Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

48 files changed, 61047 insertions, 0 deletions

diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
new file mode 100644
index 000000000..86699c8ca
--- /dev/null
+++ b/fs/ext4/Kconfig
@@ -0,0 +1,119 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# Ext3 configs are here for backward compatibility with old configs which may
+# have EXT3_FS set but not EXT4_FS set and thus would result in non-bootable
+# kernels after the removal of ext3 driver.
+config EXT3_FS
+	tristate "The Extended 3 (ext3) filesystem"
+	select EXT4_FS
+	help
+	  This config option is here only for backward compatibility. ext3
+	  filesystem is now handled by the ext4 driver.
+
+config EXT3_FS_POSIX_ACL
+	bool "Ext3 POSIX Access Control Lists"
+	depends on EXT3_FS
+	select EXT4_FS_POSIX_ACL
+	select FS_POSIX_ACL
+	help
+	  This config option is here only for backward compatibility. ext3
+	  filesystem is now handled by the ext4 driver.
+
+config EXT3_FS_SECURITY
+	bool "Ext3 Security Labels"
+	depends on EXT3_FS
+	select EXT4_FS_SECURITY
+	help
+	  This config option is here only for backward compatibility. ext3
+	  filesystem is now handled by the ext4 driver.
+
+config EXT4_FS
+	tristate "The Extended 4 (ext4) filesystem"
+	select JBD2
+	select CRC16
+	select CRYPTO
+	select CRYPTO_CRC32C
+	select FS_IOMAP
+	select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
+	help
+	  This is the next generation of the ext3 filesystem.
+
+	  Unlike the change from ext2 filesystem to ext3 filesystem,
+	  the on-disk format of ext4 is not forwards compatible with
+	  ext3; it is based on extent maps and it supports 48-bit
+	  physical block numbers.  The ext4 filesystem also supports delayed
+	  allocation, persistent preallocation, high resolution time stamps,
+	  and a number of other features to improve performance and speed
+	  up fsck time.  For more information, please see the web pages at
+	  http://ext4.wiki.kernel.org.
+
+	  The ext4 filesystem supports mounting an ext3 filesystem; while there
+	  are some performance gains from the delayed allocation and inode
+	  table readahead, the best performance gains require enabling ext4
+	  features in the filesystem using tune2fs, or formatting a new
+	  filesystem as an ext4 filesystem initially. Without explicit enabling
+	  of ext4 features, the on disk filesystem format stays fully backward
+	  compatible.
+
+	  To compile this file system support as a module, choose M here. The
+	  module will be called ext4.
+
+	  If unsure, say N.
+
+config EXT4_USE_FOR_EXT2
+	bool "Use ext4 for ext2 file systems"
+	depends on EXT4_FS
+	depends on EXT2_FS=n
+	default y
+	help
+	  Allow the ext4 file system driver code to be used for ext2
+	  file system mounts.  This allows users to reduce their
+	  compiled kernel size by using one file system driver for
+	  ext2, ext3, and ext4 file systems.
+
+config EXT4_FS_POSIX_ACL
+	bool "Ext4 POSIX Access Control Lists"
+	depends on EXT4_FS
+	select FS_POSIX_ACL
+	help
+	  POSIX Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  If you don't know what Access Control Lists are, say N
+
+config EXT4_FS_SECURITY
+	bool "Ext4 Security Labels"
+	depends on EXT4_FS
+	help
+	  Security labels support alternative access control models
+	  implemented by security modules like SELinux.  This option
+	  enables an extended attribute handler for file security
+	  labels in the ext4 filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.
+
+config EXT4_DEBUG
+	bool "Ext4 debugging support"
+	depends on EXT4_FS
+	help
+	  Enables run-time debugging support for the ext4 filesystem.
+
+	  If you select Y here, then you will be able to turn on debugging
+	  using dynamic debug control for mb_debug() / ext_debug() msgs.
+
+config EXT4_KUNIT_TESTS
+	tristate "KUnit tests for ext4" if !KUNIT_ALL_TESTS
+	depends on EXT4_FS && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the ext4 KUnit tests.
+
+	  KUnit tests run during boot and output the results to the debug log
+	  in TAP format (https://testanything.org/). Only useful for kernel devs
+	  running KUnit test harness and are not for inclusion into a production
+	  build.
+
+	  For more information on KUnit and unit tests in general please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
new file mode 100644
index 000000000..49e7af6cc
--- /dev/null
+++ b/fs/ext4/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux ext4-filesystem routines.
+#
+
+obj-$(CONFIG_EXT4_FS) += ext4.o
+
+ext4-y	:= balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \
+		extents_status.o file.o fsmap.o fsync.o hash.o ialloc.o \
+		indirect.o inline.o inode.o ioctl.o mballoc.o migrate.o \
+		mmp.o move_extent.o namei.o page-io.o readpage.o resize.o \
+		super.o symlink.o sysfs.o xattr.o xattr_hurd.o xattr_trusted.o \
+		xattr_user.o fast_commit.o
+
+ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
+ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o
+ext4-inode-test-objs			+= inode-test.o
+obj-$(CONFIG_EXT4_KUNIT_TESTS)		+= ext4-inode-test.o
+ext4-$(CONFIG_FS_VERITY)		+= verity.o
diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
new file mode 100644
index 000000000..76f634d18
--- /dev/null
+++ b/fs/ext4/acl.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/acl.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ */
+
+#include <linux/quotaops.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Convert from filesystem to in-memory representation.
+ */
+static struct posix_acl *
+ext4_acl_from_disk(const void *value, size_t size)
+{
+	const char *end = (char *)value + size;
+	int n, count;
+	struct posix_acl *acl;
+
+	if (!value)
+		return NULL;
+	if (size < sizeof(ext4_acl_header))
+		 return ERR_PTR(-EINVAL);
+	if (((ext4_acl_header *)value)->a_version !=
+	    cpu_to_le32(EXT4_ACL_VERSION))
+		return ERR_PTR(-EINVAL);
+	value = (char *)value + sizeof(ext4_acl_header);
+	count = ext4_acl_count(size);
+	if (count < 0)
+		return ERR_PTR(-EINVAL);
+	if (count == 0)
+		return NULL;
+	acl = posix_acl_alloc(count, GFP_NOFS);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+	for (n = 0; n < count; n++) {
+		ext4_acl_entry *entry =
+			(ext4_acl_entry *)value;
+		if ((char *)value + sizeof(ext4_acl_entry_short) > end)
+			goto fail;
+		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
+		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
+
+		switch (acl->a_entries[n].e_tag) {
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			value = (char *)value +
+				sizeof(ext4_acl_entry_short);
+			break;
+
+		case ACL_USER:
+			value = (char *)value + sizeof(ext4_acl_entry);
+			if ((char *)value > end)
+				goto fail;
+			acl->a_entries[n].e_uid =
+				make_kuid(&init_user_ns,
+					  le32_to_cpu(entry->e_id));
+			break;
+		case ACL_GROUP:
+			value = (char *)value + sizeof(ext4_acl_entry);
+			if ((char *)value > end)
+				goto fail;
+			acl->a_entries[n].e_gid =
+				make_kgid(&init_user_ns,
+					  le32_to_cpu(entry->e_id));
+			break;
+
+		default:
+			goto fail;
+		}
+	}
+	if (value != end)
+		goto fail;
+	return acl;
+
+fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+
+/*
+ * Convert from in-memory to filesystem representation.
+ */
+static void *
+ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
+{
+	ext4_acl_header *ext_acl;
+	char *e;
+	size_t n;
+
+	*size = ext4_acl_size(acl->a_count);
+	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
+			sizeof(ext4_acl_entry), GFP_NOFS);
+	if (!ext_acl)
+		return ERR_PTR(-ENOMEM);
+	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
+	e = (char *)ext_acl + sizeof(ext4_acl_header);
+	for (n = 0; n < acl->a_count; n++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
+		ext4_acl_entry *entry = (ext4_acl_entry *)e;
+		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch (acl_e->e_tag) {
+		case ACL_USER:
+			entry->e_id = cpu_to_le32(
+				from_kuid(&init_user_ns, acl_e->e_uid));
+			e += sizeof(ext4_acl_entry);
+			break;
+		case ACL_GROUP:
+			entry->e_id = cpu_to_le32(
+				from_kgid(&init_user_ns, acl_e->e_gid));
+			e += sizeof(ext4_acl_entry);
+			break;
+
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			e += sizeof(ext4_acl_entry_short);
+			break;
+
+		default:
+			goto fail;
+		}
+	}
+	return (char *)ext_acl;
+
+fail:
+	kfree(ext_acl);
+	return ERR_PTR(-EINVAL);
+}
+
+/*
+ * Inode operation get_posix_acl().
+ *
+ * inode->i_mutex: don't care
+ */
+struct posix_acl *
+ext4_get_acl(struct inode *inode, int type)
+{
+	int name_index;
+	char *value = NULL;
+	struct posix_acl *acl;
+	int retval;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
+	if (retval > 0) {
+		value = kmalloc(retval, GFP_NOFS);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		retval = ext4_xattr_get(inode, name_index, "", value, retval);
+	}
+	if (retval > 0)
+		acl = ext4_acl_from_disk(value, retval);
+	else if (retval == -ENODATA || retval == -ENOSYS)
+		acl = NULL;
+	else
+		acl = ERR_PTR(retval);
+	kfree(value);
+
+	return acl;
+}
+
+/*
+ * Set the access or default ACL of an inode.
+ *
+ * inode->i_mutex: down unless called from ext4_new_inode
+ */
+static int
+__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
+	     struct posix_acl *acl, int xattr_flags)
+{
+	int name_index;
+	void *value = NULL;
+	size_t size = 0;
+	int error;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	if (acl) {
+		value = ext4_acl_to_disk(acl, &size);
+		if (IS_ERR(value))
+			return (int)PTR_ERR(value);
+	}
+
+	error = ext4_xattr_set_handle(handle, inode, name_index, "",
+				      value, size, xattr_flags);
+
+	kfree(value);
+	if (!error)
+		set_cached_acl(inode, type, acl);
+
+	return error;
+}
+
+int
+ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	handle_t *handle;
+	int error, credits, retries = 0;
+	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
+	umode_t mode = inode->i_mode;
+	int update_mode = 0;
+
+	error = dquot_initialize(inode);
+	if (error)
+		return error;
+retry:
+	error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
+				       &credits);
+	if (error)
+		return error;
+
+	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if ((type == ACL_TYPE_ACCESS) && acl) {
+		error = posix_acl_update_mode(inode, &mode, &acl);
+		if (error)
+			goto out_stop;
+		if (mode != inode->i_mode)
+			update_mode = 1;
+	}
+
+	error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
+	if (!error && update_mode) {
+		inode->i_mode = mode;
+		inode->i_ctime = current_time(inode);
+		error = ext4_mark_inode_dirty(handle, inode);
+	}
+out_stop:
+	ext4_journal_stop(handle);
+	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+	return error;
+}
+
+/*
+ * Initialize the ACLs of a new inode. Called from ext4_new_inode.
+ *
+ * dir->i_mutex: down
+ * inode->i_mutex: up (access to inode is still exclusive)
+ */
+int
+ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	struct posix_acl *default_acl, *acl;
+	int error;
+
+	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
+	if (error)
+		return error;
+
+	if (default_acl) {
+		error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
+				       default_acl, XATTR_CREATE);
+		posix_acl_release(default_acl);
+	} else {
+		inode->i_default_acl = NULL;
+	}
+	if (acl) {
+		if (!error)
+			error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
+					       acl, XATTR_CREATE);
+		posix_acl_release(acl);
+	} else {
+		inode->i_acl = NULL;
+	}
+	return error;
+}
diff --git a/fs/ext4/acl.h b/fs/ext4/acl.h
new file mode 100644
index 000000000..7f3b25b3f
--- /dev/null
+++ b/fs/ext4/acl.h
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+  File: fs/ext4/acl.h
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/posix_acl_xattr.h>
+
+#define EXT4_ACL_VERSION	0x0001
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+	__le32		e_id;
+} ext4_acl_entry;
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+} ext4_acl_entry_short;
+
+typedef struct {
+	__le32		a_version;
+} ext4_acl_header;
+
+static inline size_t ext4_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(ext4_acl_header) +
+		       count * sizeof(ext4_acl_entry_short);
+	} else {
+		return sizeof(ext4_acl_header) +
+		       4 * sizeof(ext4_acl_entry_short) +
+		       (count - 4) * sizeof(ext4_acl_entry);
+	}
+}
+
+static inline int ext4_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(ext4_acl_header);
+	s = size - 4 * sizeof(ext4_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(ext4_acl_entry_short))
+			return -1;
+		return size / sizeof(ext4_acl_entry_short);
+	} else {
+		if (s % sizeof(ext4_acl_entry))
+			return -1;
+		return s / sizeof(ext4_acl_entry) + 4;
+	}
+}
+
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+
+/* acl.c */
+struct posix_acl *ext4_get_acl(struct inode *inode, int type);
+int ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+extern int ext4_init_acl(handle_t *, struct inode *, struct inode *);
+
+#else  /* CONFIG_EXT4_FS_POSIX_ACL */
+#include <linux/sched.h>
+#define ext4_get_acl NULL
+#define ext4_set_acl NULL
+
+static inline int
+ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	/* usually, the umask is applied by posix_acl_create(), but if
+	   ext4 ACL support is disabled at compile time, we need to do
+	   it here, because posix_acl_create() will never be called */
+	inode->i_mode &= ~current_umask();
+
+	return 0;
+}
+#endif  /* CONFIG_EXT4_FS_POSIX_ACL */
+
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
new file mode 100644
index 000000000..bdbf13041
--- /dev/null
+++ b/fs/ext4/balloc.c
@@ -0,0 +1,985 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/balloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/time.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "mballoc.h"
+
+#include <trace/events/ext4.h>
+
+static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
+					    ext4_group_t block_group);
+/*
+ * balloc.c contains the blocks allocation and deallocation routines
+ */
+
+/*
+ * Calculate block group number for a given block number
+ */
+ext4_group_t ext4_get_group_number(struct super_block *sb,
+				   ext4_fsblk_t block)
+{
+	ext4_group_t group;
+
+	if (test_opt2(sb, STD_GROUP_SIZE))
+		group = (block -
+			 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >>
+			(EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3);
+	else
+		ext4_get_group_no_and_offset(sb, block, &group, NULL);
+	return group;
+}
+
+/*
+ * Calculate the block group number and offset into the block/cluster
+ * allocation bitmap, given a block number
+ */
+void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
+		ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	ext4_grpblk_t offset;
+
+	blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
+	offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
+		EXT4_SB(sb)->s_cluster_bits;
+	if (offsetp)
+		*offsetp = offset;
+	if (blockgrpp)
+		*blockgrpp = blocknr;
+
+}
+
+/*
+ * Check whether the 'block' lives within the 'block_group'. Returns 1 if so
+ * and 0 otherwise.
+ */
+static inline int ext4_block_in_group(struct super_block *sb,
+				      ext4_fsblk_t block,
+				      ext4_group_t block_group)
+{
+	ext4_group_t actual_group;
+
+	actual_group = ext4_get_group_number(sb, block);
+	return (actual_group == block_group) ? 1 : 0;
+}
+
+/* Return the number of clusters used for file system metadata; this
+ * represents the overhead needed by the file system.
+ */
+static unsigned ext4_num_overhead_clusters(struct super_block *sb,
+					   ext4_group_t block_group,
+					   struct ext4_group_desc *gdp)
+{
+	unsigned num_clusters;
+	int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;
+	ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);
+	ext4_fsblk_t itbl_blk;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	/* This is the number of clusters used by the superblock,
+	 * block group descriptors, and reserved block group
+	 * descriptor blocks */
+	num_clusters = ext4_num_base_meta_clusters(sb, block_group);
+
+	/*
+	 * For the allocation bitmaps and inode table, we first need
+	 * to check to see if the block is in the block group.  If it
+	 * is, then check to see if the cluster is already accounted
+	 * for in the clusters used for the base metadata cluster, or
+	 * if we can increment the base metadata cluster to include
+	 * that block.  Otherwise, we will have to track the cluster
+	 * used for the allocation bitmap or inode table explicitly.
+	 * Normally all of these blocks are contiguous, so the special
+	 * case handling shouldn't be necessary except for *very*
+	 * unusual file system layouts.
+	 */
+	if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
+		block_cluster = EXT4_B2C(sbi,
+					 ext4_block_bitmap(sb, gdp) - start);
+		if (block_cluster < num_clusters)
+			block_cluster = -1;
+		else if (block_cluster == num_clusters) {
+			num_clusters++;
+			block_cluster = -1;
+		}
+	}
+
+	if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
+		inode_cluster = EXT4_B2C(sbi,
+					 ext4_inode_bitmap(sb, gdp) - start);
+		if (inode_cluster < num_clusters)
+			inode_cluster = -1;
+		else if (inode_cluster == num_clusters) {
+			num_clusters++;
+			inode_cluster = -1;
+		}
+	}
+
+	itbl_blk = ext4_inode_table(sb, gdp);
+	for (i = 0; i < sbi->s_itb_per_group; i++) {
+		if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
+			c = EXT4_B2C(sbi, itbl_blk + i - start);
+			if ((c < num_clusters) || (c == inode_cluster) ||
+			    (c == block_cluster) || (c == itbl_cluster))
+				continue;
+			if (c == num_clusters) {
+				num_clusters++;
+				continue;
+			}
+			num_clusters++;
+			itbl_cluster = c;
+		}
+	}
+
+	if (block_cluster != -1)
+		num_clusters++;
+	if (inode_cluster != -1)
+		num_clusters++;
+
+	return num_clusters;
+}
+
+static unsigned int num_clusters_in_group(struct super_block *sb,
+					  ext4_group_t block_group)
+{
+	unsigned int blocks;
+
+	if (block_group == ext4_get_groups_count(sb) - 1) {
+		/*
+		 * Even though mke2fs always initializes the first and
+		 * last group, just in case some other tool was used,
+		 * we need to make sure we calculate the right free
+		 * blocks.
+		 */
+		blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -
+			ext4_group_first_block_no(sb, block_group);
+	} else
+		blocks = EXT4_BLOCKS_PER_GROUP(sb);
+	return EXT4_NUM_B2C(EXT4_SB(sb), blocks);
+}
+
+/* Initializes an uninitialized block bitmap */
+static int ext4_init_block_bitmap(struct super_block *sb,
+				   struct buffer_head *bh,
+				   ext4_group_t block_group,
+				   struct ext4_group_desc *gdp)
+{
+	unsigned int bit, bit_max;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_fsblk_t start, tmp;
+
+	J_ASSERT_BH(bh, buffer_locked(bh));
+
+	/* If checksum is bad mark all blocks used to prevent allocation
+	 * essentially implementing a per-group read-only flag. */
+	if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT |
+					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
+		return -EFSBADCRC;
+	}
+	memset(bh->b_data, 0, sb->s_blocksize);
+
+	bit_max = ext4_num_base_meta_clusters(sb, block_group);
+	if ((bit_max >> 3) >= bh->b_size)
+		return -EFSCORRUPTED;
+
+	for (bit = 0; bit < bit_max; bit++)
+		ext4_set_bit(bit, bh->b_data);
+
+	start = ext4_group_first_block_no(sb, block_group);
+
+	/* Set bits for block and inode bitmaps, and inode table */
+	tmp = ext4_block_bitmap(sb, gdp);
+	if (ext4_block_in_group(sb, tmp, block_group))
+		ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
+
+	tmp = ext4_inode_bitmap(sb, gdp);
+	if (ext4_block_in_group(sb, tmp, block_group))
+		ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
+
+	tmp = ext4_inode_table(sb, gdp);
+	for (; tmp < ext4_inode_table(sb, gdp) +
+		     sbi->s_itb_per_group; tmp++) {
+		if (ext4_block_in_group(sb, tmp, block_group))
+			ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
+	}
+
+	/*
+	 * Also if the number of blocks within the group is less than
+	 * the blocksize * 8 ( which is the size of bitmap ), set rest
+	 * of the block bitmap to 1
+	 */
+	ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
+			     sb->s_blocksize * 8, bh->b_data);
+	return 0;
+}
+
+/* Return the number of free blocks in a block group.  It is used when
+ * the block bitmap is uninitialized, so we can't just count the bits
+ * in the bitmap. */
+unsigned ext4_free_clusters_after_init(struct super_block *sb,
+				       ext4_group_t block_group,
+				       struct ext4_group_desc *gdp)
+{
+	return num_clusters_in_group(sb, block_group) - 
+		ext4_num_overhead_clusters(sb, block_group, gdp);
+}
+
+/*
+ * The free blocks are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.  The descriptors are loaded in memory
+ * when a file system is mounted (see ext4_fill_super).
+ */
+
+/**
+ * ext4_get_group_desc() -- load group descriptor from disk
+ * @sb:			super block
+ * @block_group:	given block group
+ * @bh:			pointer to the buffer head to store the block
+ *			group descriptor
+ */
+struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
+					     ext4_group_t block_group,
+					     struct buffer_head **bh)
+{
+	unsigned int group_desc;
+	unsigned int offset;
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	struct ext4_group_desc *desc;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct buffer_head *bh_p;
+
+	if (block_group >= ngroups) {
+		ext4_error(sb, "block_group >= groups_count - block_group = %u,"
+			   " groups_count = %u", block_group, ngroups);
+
+		return NULL;
+	}
+
+	group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
+	offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
+	bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc);
+	/*
+	 * sbi_array_rcu_deref returns with rcu unlocked, this is ok since
+	 * the pointer being dereferenced won't be dereferenced again. By
+	 * looking at the usage in add_new_gdb() the value isn't modified,
+	 * just the pointer, and so it remains valid.
+	 */
+	if (!bh_p) {
+		ext4_error(sb, "Group descriptor not loaded - "
+			   "block_group = %u, group_desc = %u, desc = %u",
+			   block_group, group_desc, offset);
+		return NULL;
+	}
+
+	desc = (struct ext4_group_desc *)(
+		(__u8 *)bh_p->b_data +
+		offset * EXT4_DESC_SIZE(sb));
+	if (bh)
+		*bh = bh_p;
+	return desc;
+}
+
+static ext4_fsblk_t ext4_valid_block_bitmap_padding(struct super_block *sb,
+						    ext4_group_t block_group,
+						    struct buffer_head *bh)
+{
+	ext4_grpblk_t next_zero_bit;
+	unsigned long bitmap_size = sb->s_blocksize * 8;
+	unsigned int offset = num_clusters_in_group(sb, block_group);
+
+	if (bitmap_size <= offset)
+		return 0;
+
+	next_zero_bit = ext4_find_next_zero_bit(bh->b_data, bitmap_size, offset);
+
+	return (next_zero_bit < bitmap_size ? next_zero_bit : 0);
+}
+
+struct ext4_group_info *ext4_get_group_info(struct super_block *sb,
+					    ext4_group_t group)
+{
+	struct ext4_group_info **grp_info;
+	long indexv, indexh;
+
+	if (unlikely(group >= EXT4_SB(sb)->s_groups_count))
+		return NULL;
+	indexv = group >> (EXT4_DESC_PER_BLOCK_BITS(sb));
+	indexh = group & ((EXT4_DESC_PER_BLOCK(sb)) - 1);
+	grp_info = sbi_array_rcu_deref(EXT4_SB(sb), s_group_info, indexv);
+	return grp_info[indexh];
+}
+
+/*
+ * Return the block number which was discovered to be invalid, or 0 if
+ * the block bitmap is valid.
+ */
+static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
+					    struct ext4_group_desc *desc,
+					    ext4_group_t block_group,
+					    struct buffer_head *bh)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_grpblk_t offset;
+	ext4_grpblk_t next_zero_bit;
+	ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb);
+	ext4_fsblk_t blk;
+	ext4_fsblk_t group_first_block;
+
+	if (ext4_has_feature_flex_bg(sb)) {
+		/* with FLEX_BG, the inode/block bitmaps and itable
+		 * blocks may not be in the group at all
+		 * so the bitmap validation will be skipped for those groups
+		 * or it has to also read the block group where the bitmaps
+		 * are located to verify they are set.
+		 */
+		return 0;
+	}
+	group_first_block = ext4_group_first_block_no(sb, block_group);
+
+	/* check whether block bitmap block number is set */
+	blk = ext4_block_bitmap(sb, desc);
+	offset = blk - group_first_block;
+	if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
+	    !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
+		/* bad block bitmap */
+		return blk;
+
+	/* check whether the inode bitmap block number is set */
+	blk = ext4_inode_bitmap(sb, desc);
+	offset = blk - group_first_block;
+	if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
+	    !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
+		/* bad block bitmap */
+		return blk;
+
+	/* check whether the inode table block number is set */
+	blk = ext4_inode_table(sb, desc);
+	offset = blk - group_first_block;
+	if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
+	    EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit)
+		return blk;
+	next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
+			EXT4_B2C(sbi, offset + sbi->s_itb_per_group),
+			EXT4_B2C(sbi, offset));
+	if (next_zero_bit <
+	    EXT4_B2C(sbi, offset + sbi->s_itb_per_group))
+		/* bad bitmap for inode tables */
+		return blk;
+	return 0;
+}
+
+static int ext4_validate_block_bitmap(struct super_block *sb,
+				      struct ext4_group_desc *desc,
+				      ext4_group_t block_group,
+				      struct buffer_head *bh)
+{
+	ext4_fsblk_t	blk;
+	struct ext4_group_info *grp;
+
+	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	grp = ext4_get_group_info(sb, block_group);
+
+	if (buffer_verified(bh))
+		return 0;
+	if (!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+		return -EFSCORRUPTED;
+
+	ext4_lock_group(sb, block_group);
+	if (buffer_verified(bh))
+		goto verified;
+	if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
+						    desc, bh) ||
+		     ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) {
+		ext4_unlock_group(sb, block_group);
+		ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		return -EFSBADCRC;
+	}
+	blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
+	if (unlikely(blk != 0)) {
+		ext4_unlock_group(sb, block_group);
+		ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
+			   block_group, blk);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		return -EFSCORRUPTED;
+	}
+	blk = ext4_valid_block_bitmap_padding(sb, block_group, bh);
+	if (unlikely(blk != 0)) {
+		ext4_unlock_group(sb, block_group);
+		ext4_error(sb, "bg %u: block %llu: padding at end of block bitmap is not set",
+			   block_group, blk);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+						 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		return -EFSCORRUPTED;
+	}
+	set_buffer_verified(bh);
+verified:
+	ext4_unlock_group(sb, block_group);
+	return 0;
+}
+
+/**
+ * ext4_read_block_bitmap_nowait()
+ * @sb:			super block
+ * @block_group:	given block group
+ *
+ * Read the bitmap for a given block_group,and validate the
+ * bits for block/inode/inode tables are set in the bitmaps
+ *
+ * Return buffer_head on success or an ERR_PTR in case of failure.
+ */
+struct buffer_head *
+ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group,
+			      bool ignore_locked)
+{
+	struct ext4_group_desc *desc;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct buffer_head *bh;
+	ext4_fsblk_t bitmap_blk;
+	int err;
+
+	desc = ext4_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		return ERR_PTR(-EFSCORRUPTED);
+	bitmap_blk = ext4_block_bitmap(sb, desc);
+	if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
+	    (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
+		ext4_error(sb, "Invalid block bitmap block %llu in "
+			   "block_group %u", bitmap_blk, block_group);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+	bh = sb_getblk(sb, bitmap_blk);
+	if (unlikely(!bh)) {
+		ext4_warning(sb, "Cannot get buffer for block bitmap - "
+			     "block_group = %u, block_bitmap = %llu",
+			     block_group, bitmap_blk);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	if (ignore_locked && buffer_locked(bh)) {
+		/* buffer under IO already, return if called for prefetching */
+		put_bh(bh);
+		return NULL;
+	}
+
+	if (bitmap_uptodate(bh))
+		goto verify;
+
+	lock_buffer(bh);
+	if (bitmap_uptodate(bh)) {
+		unlock_buffer(bh);
+		goto verify;
+	}
+	ext4_lock_group(sb, block_group);
+	if (ext4_has_group_desc_csum(sb) &&
+	    (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+		if (block_group == 0) {
+			ext4_unlock_group(sb, block_group);
+			unlock_buffer(bh);
+			ext4_error(sb, "Block bitmap for bg 0 marked "
+				   "uninitialized");
+			err = -EFSCORRUPTED;
+			goto out;
+		}
+		err = ext4_init_block_bitmap(sb, bh, block_group, desc);
+		set_bitmap_uptodate(bh);
+		set_buffer_uptodate(bh);
+		set_buffer_verified(bh);
+		ext4_unlock_group(sb, block_group);
+		unlock_buffer(bh);
+		if (err) {
+			ext4_error(sb, "Failed to init block bitmap for group "
+				   "%u: %d", block_group, err);
+			goto out;
+		}
+		goto verify;
+	}
+	ext4_unlock_group(sb, block_group);
+	if (buffer_uptodate(bh)) {
+		/*
+		 * if not uninit if bh is uptodate,
+		 * bitmap is also uptodate
+		 */
+		set_bitmap_uptodate(bh);
+		unlock_buffer(bh);
+		goto verify;
+	}
+	/*
+	 * submit the buffer_head for reading
+	 */
+	set_buffer_new(bh);
+	trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked);
+	ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO |
+			    (ignore_locked ? REQ_RAHEAD : 0),
+			    ext4_end_bitmap_read);
+	return bh;
+verify:
+	err = ext4_validate_block_bitmap(sb, desc, block_group, bh);
+	if (err)
+		goto out;
+	return bh;
+out:
+	put_bh(bh);
+	return ERR_PTR(err);
+}
+
+/* Returns 0 on success, -errno on error */
+int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
+			   struct buffer_head *bh)
+{
+	struct ext4_group_desc *desc;
+
+	if (!buffer_new(bh))
+		return 0;
+	desc = ext4_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		return -EFSCORRUPTED;
+	wait_on_buffer(bh);
+	ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO);
+	if (!buffer_uptodate(bh)) {
+		ext4_error_err(sb, EIO, "Cannot read block bitmap - "
+			       "block_group = %u, block_bitmap = %llu",
+			       block_group, (unsigned long long) bh->b_blocknr);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		return -EIO;
+	}
+	clear_buffer_new(bh);
+	/* Panic or remount fs read-only if block bitmap is invalid */
+	return ext4_validate_block_bitmap(sb, desc, block_group, bh);
+}
+
+struct buffer_head *
+ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
+{
+	struct buffer_head *bh;
+	int err;
+
+	bh = ext4_read_block_bitmap_nowait(sb, block_group, false);
+	if (IS_ERR(bh))
+		return bh;
+	err = ext4_wait_block_bitmap(sb, block_group, bh);
+	if (err) {
+		put_bh(bh);
+		return ERR_PTR(err);
+	}
+	return bh;
+}
+
+/**
+ * ext4_has_free_clusters()
+ * @sbi:	in-core super block structure.
+ * @nclusters:	number of needed blocks
+ * @flags:	flags from ext4_mb_new_blocks()
+ *
+ * Check if filesystem has nclusters free & available for allocation.
+ * On success return 1, return 0 on failure.
+ */
+static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
+				  s64 nclusters, unsigned int flags)
+{
+	s64 free_clusters, dirty_clusters, rsv, resv_clusters;
+	struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
+	struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
+
+	free_clusters  = percpu_counter_read_positive(fcc);
+	dirty_clusters = percpu_counter_read_positive(dcc);
+	resv_clusters = atomic64_read(&sbi->s_resv_clusters);
+
+	/*
+	 * r_blocks_count should always be multiple of the cluster ratio so
+	 * we are safe to do a plane bit shift only.
+	 */
+	rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
+	      resv_clusters;
+
+	if (free_clusters - (nclusters + rsv + dirty_clusters) <
+					EXT4_FREECLUSTERS_WATERMARK) {
+		free_clusters  = percpu_counter_sum_positive(fcc);
+		dirty_clusters = percpu_counter_sum_positive(dcc);
+	}
+	/* Check whether we have space after accounting for current
+	 * dirty clusters & root reserved clusters.
+	 */
+	if (free_clusters >= (rsv + nclusters + dirty_clusters))
+		return 1;
+
+	/* Hm, nope.  Are (enough) root reserved clusters available? */
+	if (uid_eq(sbi->s_resuid, current_fsuid()) ||
+	    (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
+	    capable(CAP_SYS_RESOURCE) ||
+	    (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
+
+		if (free_clusters >= (nclusters + dirty_clusters +
+				      resv_clusters))
+			return 1;
+	}
+	/* No free blocks. Let's see if we can dip into reserved pool */
+	if (flags & EXT4_MB_USE_RESERVED) {
+		if (free_clusters >= (nclusters + dirty_clusters))
+			return 1;
+	}
+
+	return 0;
+}
+
+int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
+			     s64 nclusters, unsigned int flags)
+{
+	if (ext4_has_free_clusters(sbi, nclusters, flags)) {
+		percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
+		return 0;
+	} else
+		return -ENOSPC;
+}
+
+/**
+ * ext4_should_retry_alloc() - check if a block allocation should be retried
+ * @sb:			superblock
+ * @retries:		number of retry attempts made so far
+ *
+ * ext4_should_retry_alloc() is called when ENOSPC is returned while
+ * attempting to allocate blocks.  If there's an indication that a pending
+ * journal transaction might free some space and allow another attempt to
+ * succeed, this function will wait for the current or committing transaction
+ * to complete and then return TRUE.
+ */
+int ext4_should_retry_alloc(struct super_block *sb, int *retries)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!sbi->s_journal)
+		return 0;
+
+	if (++(*retries) > 3) {
+		percpu_counter_inc(&sbi->s_sra_exceeded_retry_limit);
+		return 0;
+	}
+
+	/*
+	 * if there's no indication that blocks are about to be freed it's
+	 * possible we just missed a transaction commit that did so
+	 */
+	smp_mb();
+	if (sbi->s_mb_free_pending == 0)
+		return ext4_has_free_clusters(sbi, 1, 0);
+
+	/*
+	 * it's possible we've just missed a transaction commit here,
+	 * so ignore the returned status
+	 */
+	jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
+	(void) jbd2_journal_force_commit_nested(sbi->s_journal);
+	return 1;
+}
+
+/*
+ * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @count:		pointer to total number of clusters needed
+ * @errp:               error code
+ *
+ * Return 1st allocated block number on success, *count stores total account
+ * error stores in errp pointer
+ */
+ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
+				  ext4_fsblk_t goal, unsigned int flags,
+				  unsigned long *count, int *errp)
+{
+	struct ext4_allocation_request ar;
+	ext4_fsblk_t ret;
+
+	memset(&ar, 0, sizeof(ar));
+	/* Fill with neighbour allocated blocks */
+	ar.inode = inode;
+	ar.goal = goal;
+	ar.len = count ? *count : 1;
+	ar.flags = flags;
+
+	ret = ext4_mb_new_blocks(handle, &ar, errp);
+	if (count)
+		*count = ar.len;
+	/*
+	 * Account for the allocated meta blocks.  We will never
+	 * fail EDQUOT for metdata, but we do account for it.
+	 */
+	if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) {
+		dquot_alloc_block_nofail(inode,
+				EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
+	}
+	return ret;
+}
+
+/**
+ * ext4_count_free_clusters() -- count filesystem free clusters
+ * @sb:		superblock
+ *
+ * Adds up the number of free clusters from each block group.
+ */
+ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
+{
+	ext4_fsblk_t desc_count;
+	struct ext4_group_desc *gdp;
+	ext4_group_t i;
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	struct ext4_group_info *grp;
+#ifdef EXT4FS_DEBUG
+	struct ext4_super_block *es;
+	ext4_fsblk_t bitmap_count;
+	unsigned int x;
+	struct buffer_head *bitmap_bh = NULL;
+
+	es = EXT4_SB(sb)->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		grp = NULL;
+		if (EXT4_SB(sb)->s_group_info)
+			grp = ext4_get_group_info(sb, i);
+		if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+			desc_count += ext4_free_group_clusters(sb, gdp);
+		brelse(bitmap_bh);
+		bitmap_bh = ext4_read_block_bitmap(sb, i);
+		if (IS_ERR(bitmap_bh)) {
+			bitmap_bh = NULL;
+			continue;
+		}
+
+		x = ext4_count_free(bitmap_bh->b_data,
+				    EXT4_CLUSTERS_PER_GROUP(sb) / 8);
+		printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
+			i, ext4_free_group_clusters(sb, gdp), x);
+		bitmap_count += x;
+	}
+	brelse(bitmap_bh);
+	printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
+	       ", computed = %llu, %llu\n",
+	       EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
+	       desc_count, bitmap_count);
+	return bitmap_count;
+#else
+	desc_count = 0;
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		grp = NULL;
+		if (EXT4_SB(sb)->s_group_info)
+			grp = ext4_get_group_info(sb, i);
+		if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
+			desc_count += ext4_free_group_clusters(sb, gdp);
+	}
+
+	return desc_count;
+#endif
+}
+
+static inline int test_root(ext4_group_t a, int b)
+{
+	while (1) {
+		if (a < b)
+			return 0;
+		if (a == b)
+			return 1;
+		if ((a % b) != 0)
+			return 0;
+		a = a / b;
+	}
+}
+
+/**
+ *	ext4_bg_has_super - number of blocks used by the superblock in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the superblock (primary or backup)
+ *	in this group.  Currently this will be only 0 or 1.
+ */
+int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	if (group == 0)
+		return 1;
+	if (ext4_has_feature_sparse_super2(sb)) {
+		if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
+		    group == le32_to_cpu(es->s_backup_bgs[1]))
+			return 1;
+		return 0;
+	}
+	if ((group <= 1) || !ext4_has_feature_sparse_super(sb))
+		return 1;
+	if (!(group & 1))
+		return 0;
+	if (test_root(group, 3) || (test_root(group, 5)) ||
+	    test_root(group, 7))
+		return 1;
+
+	return 0;
+}
+
+static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
+					ext4_group_t group)
+{
+	unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
+	ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
+	ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
+
+	if (group == first || group == first + 1 || group == last)
+		return 1;
+	return 0;
+}
+
+static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
+					ext4_group_t group)
+{
+	if (!ext4_bg_has_super(sb, group))
+		return 0;
+
+	if (ext4_has_feature_meta_bg(sb))
+		return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
+	else
+		return EXT4_SB(sb)->s_gdb_count;
+}
+
+/**
+ *	ext4_bg_num_gdb - number of blocks used by the group table in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the group descriptor table
+ *	(primary or backup) in this group.  In the future there may be a
+ *	different number of descriptor blocks in each group.
+ */
+unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
+{
+	unsigned long first_meta_bg =
+			le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
+	unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
+
+	if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg)
+		return ext4_bg_num_gdb_nometa(sb, group);
+
+	return ext4_bg_num_gdb_meta(sb,group);
+
+}
+
+/*
+ * This function returns the number of file system metadata blocks at
+ * the beginning of a block group, including the reserved gdt blocks.
+ */
+unsigned int ext4_num_base_meta_blocks(struct super_block *sb,
+				       ext4_group_t block_group)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	unsigned num;
+
+	/* Check for superblock and gdt backups in this group */
+	num = ext4_bg_has_super(sb, block_group);
+
+	if (!ext4_has_feature_meta_bg(sb) ||
+	    block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
+			  sbi->s_desc_per_block) {
+		if (num) {
+			num += ext4_bg_num_gdb(sb, block_group);
+			num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
+		}
+	} else { /* For META_BG_BLOCK_GROUPS */
+		num += ext4_bg_num_gdb(sb, block_group);
+	}
+	return num;
+}
+
+static unsigned int ext4_num_base_meta_clusters(struct super_block *sb,
+						ext4_group_t block_group)
+{
+	return EXT4_NUM_B2C(EXT4_SB(sb), ext4_num_base_meta_blocks(sb, block_group));
+}
+
+/**
+ *	ext4_inode_to_goal_block - return a hint for block allocation
+ *	@inode: inode for block allocation
+ *
+ *	Return the ideal location to start allocating blocks for a
+ *	newly created inode.
+ */
+ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	ext4_group_t block_group;
+	ext4_grpblk_t colour;
+	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
+	ext4_fsblk_t bg_start;
+	ext4_fsblk_t last_block;
+
+	block_group = ei->i_block_group;
+	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
+		/*
+		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
+		 * block groups per flexgroup, reserve the first block
+		 * group for directories and special files.  Regular
+		 * files will start at the second block group.  This
+		 * tends to speed up directory access and improves
+		 * fsck times.
+		 */
+		block_group &= ~(flex_size-1);
+		if (S_ISREG(inode->i_mode))
+			block_group++;
+	}
+	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
+	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
+
+	/*
+	 * If we are doing delayed allocation, we don't need take
+	 * colour into account.
+	 */
+	if (test_opt(inode->i_sb, DELALLOC))
+		return bg_start;
+
+	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
+		colour = (task_pid_nr(current) % 16) *
+			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+	else
+		colour = (task_pid_nr(current) % 16) *
+			((last_block - bg_start) / 16);
+	return bg_start + colour;
+}
+
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
new file mode 100644
index 000000000..f63e028c6
--- /dev/null
+++ b/fs/ext4/bitmap.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/bitmap.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/buffer_head.h>
+#include "ext4.h"
+
+unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
+{
+	return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
+}
+
+int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh, int sz)
+{
+	__u32 hi;
+	__u32 provided, calculated;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!ext4_has_metadata_csum(sb))
+		return 1;
+
+	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
+	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
+		hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
+		provided |= (hi << 16);
+	} else
+		calculated &= 0xFFFF;
+
+	return provided == calculated;
+}
+
+void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh, int sz)
+{
+	__u32 csum;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!ext4_has_metadata_csum(sb))
+		return;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
+		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}
+
+int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh)
+{
+	__u32 hi;
+	__u32 provided, calculated;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
+
+	if (!ext4_has_metadata_csum(sb))
+		return 1;
+
+	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
+	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
+		hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
+		provided |= (hi << 16);
+	} else
+		calculated &= 0xFFFF;
+
+	if (provided == calculated)
+		return 1;
+
+	return 0;
+}
+
+void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh)
+{
+	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
+	__u32 csum;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!ext4_has_metadata_csum(sb))
+		return;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
+		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}
diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
new file mode 100644
index 000000000..295e89d93
--- /dev/null
+++ b/fs/ext4/block_validity.c
@@ -0,0 +1,373 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/block_validity.c
+ *
+ * Copyright (C) 2009
+ * Theodore Ts'o (tytso@mit.edu)
+ *
+ * Track which blocks in the filesystem are metadata blocks that
+ * should never be used as data blocks by files or directories.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include "ext4.h"
+
+struct ext4_system_zone {
+	struct rb_node	node;
+	ext4_fsblk_t	start_blk;
+	unsigned int	count;
+	u32		ino;
+};
+
+static struct kmem_cache *ext4_system_zone_cachep;
+
+int __init ext4_init_system_zone(void)
+{
+	ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
+	if (ext4_system_zone_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+void ext4_exit_system_zone(void)
+{
+	rcu_barrier();
+	kmem_cache_destroy(ext4_system_zone_cachep);
+}
+
+static inline int can_merge(struct ext4_system_zone *entry1,
+		     struct ext4_system_zone *entry2)
+{
+	if ((entry1->start_blk + entry1->count) == entry2->start_blk &&
+	    entry1->ino == entry2->ino)
+		return 1;
+	return 0;
+}
+
+static void release_system_zone(struct ext4_system_blocks *system_blks)
+{
+	struct ext4_system_zone	*entry, *n;
+
+	rbtree_postorder_for_each_entry_safe(entry, n,
+				&system_blks->root, node)
+		kmem_cache_free(ext4_system_zone_cachep, entry);
+}
+
+/*
+ * Mark a range of blocks as belonging to the "system zone" --- that
+ * is, filesystem metadata blocks which should never be used by
+ * inodes.
+ */
+static int add_system_zone(struct ext4_system_blocks *system_blks,
+			   ext4_fsblk_t start_blk,
+			   unsigned int count, u32 ino)
+{
+	struct ext4_system_zone *new_entry, *entry;
+	struct rb_node **n = &system_blks->root.rb_node, *node;
+	struct rb_node *parent = NULL, *new_node = NULL;
+
+	while (*n) {
+		parent = *n;
+		entry = rb_entry(parent, struct ext4_system_zone, node);
+		if (start_blk < entry->start_blk)
+			n = &(*n)->rb_left;
+		else if (start_blk >= (entry->start_blk + entry->count))
+			n = &(*n)->rb_right;
+		else	/* Unexpected overlap of system zones. */
+			return -EFSCORRUPTED;
+	}
+
+	new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
+				     GFP_KERNEL);
+	if (!new_entry)
+		return -ENOMEM;
+	new_entry->start_blk = start_blk;
+	new_entry->count = count;
+	new_entry->ino = ino;
+	new_node = &new_entry->node;
+
+	rb_link_node(new_node, parent, n);
+	rb_insert_color(new_node, &system_blks->root);
+
+	/* Can we merge to the left? */
+	node = rb_prev(new_node);
+	if (node) {
+		entry = rb_entry(node, struct ext4_system_zone, node);
+		if (can_merge(entry, new_entry)) {
+			new_entry->start_blk = entry->start_blk;
+			new_entry->count += entry->count;
+			rb_erase(node, &system_blks->root);
+			kmem_cache_free(ext4_system_zone_cachep, entry);
+		}
+	}
+
+	/* Can we merge to the right? */
+	node = rb_next(new_node);
+	if (node) {
+		entry = rb_entry(node, struct ext4_system_zone, node);
+		if (can_merge(new_entry, entry)) {
+			new_entry->count += entry->count;
+			rb_erase(node, &system_blks->root);
+			kmem_cache_free(ext4_system_zone_cachep, entry);
+		}
+	}
+	return 0;
+}
+
+static void debug_print_tree(struct ext4_sb_info *sbi)
+{
+	struct rb_node *node;
+	struct ext4_system_zone *entry;
+	struct ext4_system_blocks *system_blks;
+	int first = 1;
+
+	printk(KERN_INFO "System zones: ");
+	rcu_read_lock();
+	system_blks = rcu_dereference(sbi->s_system_blks);
+	node = rb_first(&system_blks->root);
+	while (node) {
+		entry = rb_entry(node, struct ext4_system_zone, node);
+		printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ",
+		       entry->start_blk, entry->start_blk + entry->count - 1);
+		first = 0;
+		node = rb_next(node);
+	}
+	rcu_read_unlock();
+	printk(KERN_CONT "\n");
+}
+
+static int ext4_protect_reserved_inode(struct super_block *sb,
+				       struct ext4_system_blocks *system_blks,
+				       u32 ino)
+{
+	struct inode *inode;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_map_blocks map;
+	u32 i = 0, num;
+	int err = 0, n;
+
+	if ((ino < EXT4_ROOT_INO) ||
+	    (ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
+		return -EINVAL;
+	inode = ext4_iget(sb, ino, EXT4_IGET_SPECIAL);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+	num = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+	while (i < num) {
+		cond_resched();
+		map.m_lblk = i;
+		map.m_len = num - i;
+		n = ext4_map_blocks(NULL, inode, &map, 0);
+		if (n < 0) {
+			err = n;
+			break;
+		}
+		if (n == 0) {
+			i++;
+		} else {
+			err = add_system_zone(system_blks, map.m_pblk, n, ino);
+			if (err < 0) {
+				if (err == -EFSCORRUPTED) {
+					__ext4_error(sb, __func__, __LINE__,
+						     -err, map.m_pblk,
+						     "blocks %llu-%llu from inode %u overlap system zone",
+						     map.m_pblk,
+						     map.m_pblk + map.m_len - 1,
+						     ino);
+				}
+				break;
+			}
+			i += n;
+		}
+	}
+	iput(inode);
+	return err;
+}
+
+static void ext4_destroy_system_zone(struct rcu_head *rcu)
+{
+	struct ext4_system_blocks *system_blks;
+
+	system_blks = container_of(rcu, struct ext4_system_blocks, rcu);
+	release_system_zone(system_blks);
+	kfree(system_blks);
+}
+
+/*
+ * Build system zone rbtree which is used for block validity checking.
+ *
+ * The update of system_blks pointer in this function is protected by
+ * sb->s_umount semaphore. However we have to be careful as we can be
+ * racing with ext4_data_block_valid() calls reading system_blks rbtree
+ * protected only by RCU. That's why we first build the rbtree and then
+ * swap it in place.
+ */
+int ext4_setup_system_zone(struct super_block *sb)
+{
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_system_blocks *system_blks;
+	struct ext4_group_desc *gdp;
+	ext4_group_t i;
+	int ret;
+
+	system_blks = kzalloc(sizeof(*system_blks), GFP_KERNEL);
+	if (!system_blks)
+		return -ENOMEM;
+
+	for (i=0; i < ngroups; i++) {
+		unsigned int meta_blks = ext4_num_base_meta_blocks(sb, i);
+
+		cond_resched();
+		if (meta_blks != 0) {
+			ret = add_system_zone(system_blks,
+					ext4_group_first_block_no(sb, i),
+					meta_blks, 0);
+			if (ret)
+				goto err;
+		}
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		ret = add_system_zone(system_blks,
+				ext4_block_bitmap(sb, gdp), 1, 0);
+		if (ret)
+			goto err;
+		ret = add_system_zone(system_blks,
+				ext4_inode_bitmap(sb, gdp), 1, 0);
+		if (ret)
+			goto err;
+		ret = add_system_zone(system_blks,
+				ext4_inode_table(sb, gdp),
+				sbi->s_itb_per_group, 0);
+		if (ret)
+			goto err;
+	}
+	if (ext4_has_feature_journal(sb) && sbi->s_es->s_journal_inum) {
+		ret = ext4_protect_reserved_inode(sb, system_blks,
+				le32_to_cpu(sbi->s_es->s_journal_inum));
+		if (ret)
+			goto err;
+	}
+
+	/*
+	 * System blks rbtree complete, announce it once to prevent racing
+	 * with ext4_data_block_valid() accessing the rbtree at the same
+	 * time.
+	 */
+	rcu_assign_pointer(sbi->s_system_blks, system_blks);
+
+	if (test_opt(sb, DEBUG))
+		debug_print_tree(sbi);
+	return 0;
+err:
+	release_system_zone(system_blks);
+	kfree(system_blks);
+	return ret;
+}
+
+/*
+ * Called when the filesystem is unmounted or when remounting it with
+ * noblock_validity specified.
+ *
+ * The update of system_blks pointer in this function is protected by
+ * sb->s_umount semaphore. However we have to be careful as we can be
+ * racing with ext4_data_block_valid() calls reading system_blks rbtree
+ * protected only by RCU. So we first clear the system_blks pointer and
+ * then free the rbtree only after RCU grace period expires.
+ */
+void ext4_release_system_zone(struct super_block *sb)
+{
+	struct ext4_system_blocks *system_blks;
+
+	system_blks = rcu_dereference_protected(EXT4_SB(sb)->s_system_blks,
+					lockdep_is_held(&sb->s_umount));
+	rcu_assign_pointer(EXT4_SB(sb)->s_system_blks, NULL);
+
+	if (system_blks)
+		call_rcu(&system_blks->rcu, ext4_destroy_system_zone);
+}
+
+int ext4_sb_block_valid(struct super_block *sb, struct inode *inode,
+				ext4_fsblk_t start_blk, unsigned int count)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_system_blocks *system_blks;
+	struct ext4_system_zone *entry;
+	struct rb_node *n;
+	int ret = 1;
+
+	if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
+	    (start_blk + count < start_blk) ||
+	    (start_blk + count > ext4_blocks_count(sbi->s_es)))
+		return 0;
+
+	/*
+	 * Lock the system zone to prevent it being released concurrently
+	 * when doing a remount which inverse current "[no]block_validity"
+	 * mount option.
+	 */
+	rcu_read_lock();
+	system_blks = rcu_dereference(sbi->s_system_blks);
+	if (system_blks == NULL)
+		goto out_rcu;
+
+	n = system_blks->root.rb_node;
+	while (n) {
+		entry = rb_entry(n, struct ext4_system_zone, node);
+		if (start_blk + count - 1 < entry->start_blk)
+			n = n->rb_left;
+		else if (start_blk >= (entry->start_blk + entry->count))
+			n = n->rb_right;
+		else {
+			ret = 0;
+			if (inode)
+				ret = (entry->ino == inode->i_ino);
+			break;
+		}
+	}
+out_rcu:
+	rcu_read_unlock();
+	return ret;
+}
+
+/*
+ * Returns 1 if the passed-in block region (start_blk,
+ * start_blk+count) is valid; 0 if some part of the block region
+ * overlaps with some other filesystem metadata blocks.
+ */
+int ext4_inode_block_valid(struct inode *inode, ext4_fsblk_t start_blk,
+			  unsigned int count)
+{
+	return ext4_sb_block_valid(inode->i_sb, inode, start_blk, count);
+}
+
+int ext4_check_blockref(const char *function, unsigned int line,
+			struct inode *inode, __le32 *p, unsigned int max)
+{
+	__le32 *bref = p;
+	unsigned int blk;
+
+	if (ext4_has_feature_journal(inode->i_sb) &&
+	    (inode->i_ino ==
+	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
+		return 0;
+
+	while (bref < p+max) {
+		blk = le32_to_cpu(*bref++);
+		if (blk &&
+		    unlikely(!ext4_inode_block_valid(inode, blk, 1))) {
+			ext4_error_inode(inode, function, line, blk,
+					 "invalid block");
+			return -EFSCORRUPTED;
+		}
+	}
+	return 0;
+}
+
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
new file mode 100644
index 000000000..70a0f5e56
--- /dev/null
+++ b/fs/ext4/dir.c
@@ -0,0 +1,676 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/dir.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 directory handling functions
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * Hash Tree Directory indexing (c) 2001  Daniel Phillips
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/iversion.h>
+#include <linux/unicode.h>
+#include "ext4.h"
+#include "xattr.h"
+
+static int ext4_dx_readdir(struct file *, struct dir_context *);
+
+/**
+ * is_dx_dir() - check if a directory is using htree indexing
+ * @inode: directory inode
+ *
+ * Check if the given dir-inode refers to an htree-indexed directory
+ * (or a directory which could potentially get converted to use htree
+ * indexing).
+ *
+ * Return 1 if it is a dx dir, 0 if not
+ */
+static int is_dx_dir(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	if (ext4_has_feature_dir_index(inode->i_sb) &&
+	    ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
+	     ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
+	     ext4_has_inline_data(inode)))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Return 0 if the directory entry is OK, and 1 if there is a problem
+ *
+ * Note: this is the opposite of what ext2 and ext3 historically returned...
+ *
+ * bh passed here can be an inode block or a dir data block, depending
+ * on the inode inline data flag.
+ */
+int __ext4_check_dir_entry(const char *function, unsigned int line,
+			   struct inode *dir, struct file *filp,
+			   struct ext4_dir_entry_2 *de,
+			   struct buffer_head *bh, char *buf, int size,
+			   unsigned int offset)
+{
+	const char *error_msg = NULL;
+	const int rlen = ext4_rec_len_from_disk(de->rec_len,
+						dir->i_sb->s_blocksize);
+	const int next_offset = ((char *) de - buf) + rlen;
+
+	if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
+		error_msg = "rec_len is smaller than minimal";
+	else if (unlikely(rlen % 4 != 0))
+		error_msg = "rec_len % 4 != 0";
+	else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
+		error_msg = "rec_len is too small for name_len";
+	else if (unlikely(next_offset > size))
+		error_msg = "directory entry overrun";
+	else if (unlikely(next_offset > size - EXT4_DIR_REC_LEN(1) &&
+			  next_offset != size))
+		error_msg = "directory entry too close to block end";
+	else if (unlikely(le32_to_cpu(de->inode) >
+			le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
+		error_msg = "inode out of bounds";
+	else
+		return 0;
+
+	if (filp)
+		ext4_error_file(filp, function, line, bh->b_blocknr,
+				"bad entry in directory: %s - offset=%u, "
+				"inode=%u, rec_len=%d, name_len=%d, size=%d",
+				error_msg, offset, le32_to_cpu(de->inode),
+				rlen, de->name_len, size);
+	else
+		ext4_error_inode(dir, function, line, bh->b_blocknr,
+				"bad entry in directory: %s - offset=%u, "
+				"inode=%u, rec_len=%d, name_len=%d, size=%d",
+				 error_msg, offset, le32_to_cpu(de->inode),
+				 rlen, de->name_len, size);
+
+	return 1;
+}
+
+static int ext4_readdir(struct file *file, struct dir_context *ctx)
+{
+	unsigned int offset;
+	int i;
+	struct ext4_dir_entry_2 *de;
+	int err;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *bh = NULL;
+	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
+
+	if (IS_ENCRYPTED(inode)) {
+		err = fscrypt_get_encryption_info(inode);
+		if (err)
+			return err;
+	}
+
+	if (is_dx_dir(inode)) {
+		err = ext4_dx_readdir(file, ctx);
+		if (err != ERR_BAD_DX_DIR) {
+			return err;
+		}
+		/* Can we just clear INDEX flag to ignore htree information? */
+		if (!ext4_has_metadata_csum(sb)) {
+			/*
+			 * We don't set the inode dirty flag since it's not
+			 * critical that it gets flushed back to the disk.
+			 */
+			ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
+		}
+	}
+
+	if (ext4_has_inline_data(inode)) {
+		int has_inline_data = 1;
+		err = ext4_read_inline_dir(file, ctx,
+					   &has_inline_data);
+		if (has_inline_data)
+			return err;
+	}
+
+	if (IS_ENCRYPTED(inode)) {
+		err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, &fstr);
+		if (err < 0)
+			return err;
+	}
+
+	while (ctx->pos < inode->i_size) {
+		struct ext4_map_blocks map;
+
+		if (fatal_signal_pending(current)) {
+			err = -ERESTARTSYS;
+			goto errout;
+		}
+		cond_resched();
+		offset = ctx->pos & (sb->s_blocksize - 1);
+		map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
+		map.m_len = 1;
+		err = ext4_map_blocks(NULL, inode, &map, 0);
+		if (err == 0) {
+			/* m_len should never be zero but let's avoid
+			 * an infinite loop if it somehow is */
+			if (map.m_len == 0)
+				map.m_len = 1;
+			ctx->pos += map.m_len * sb->s_blocksize;
+			continue;
+		}
+		if (err > 0) {
+			pgoff_t index = map.m_pblk >>
+					(PAGE_SHIFT - inode->i_blkbits);
+			if (!ra_has_index(&file->f_ra, index))
+				page_cache_sync_readahead(
+					sb->s_bdev->bd_inode->i_mapping,
+					&file->f_ra, file,
+					index, 1);
+			file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
+			bh = ext4_bread(NULL, inode, map.m_lblk, 0);
+			if (IS_ERR(bh)) {
+				err = PTR_ERR(bh);
+				bh = NULL;
+				goto errout;
+			}
+		}
+
+		if (!bh) {
+			/* corrupt size?  Maybe no more blocks to read */
+			if (ctx->pos > inode->i_blocks << 9)
+				break;
+			ctx->pos += sb->s_blocksize - offset;
+			continue;
+		}
+
+		/* Check the checksum */
+		if (!buffer_verified(bh) &&
+		    !ext4_dirblock_csum_verify(inode, bh)) {
+			EXT4_ERROR_FILE(file, 0, "directory fails checksum "
+					"at offset %llu",
+					(unsigned long long)ctx->pos);
+			ctx->pos += sb->s_blocksize - offset;
+			brelse(bh);
+			bh = NULL;
+			continue;
+		}
+		set_buffer_verified(bh);
+
+		/* If the dir block has changed since the last call to
+		 * readdir(2), then we might be pointing to an invalid
+		 * dirent right now.  Scan from the start of the block
+		 * to make sure. */
+		if (!inode_eq_iversion(inode, file->f_version)) {
+			for (i = 0; i < sb->s_blocksize && i < offset; ) {
+				de = (struct ext4_dir_entry_2 *)
+					(bh->b_data + i);
+				/* It's too expensive to do a full
+				 * dirent test each time round this
+				 * loop, but we do have to test at
+				 * least that it is non-zero.  A
+				 * failure will be detected in the
+				 * dirent test below. */
+				if (ext4_rec_len_from_disk(de->rec_len,
+					sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
+					break;
+				i += ext4_rec_len_from_disk(de->rec_len,
+							    sb->s_blocksize);
+			}
+			offset = i;
+			ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
+				| offset;
+			file->f_version = inode_query_iversion(inode);
+		}
+
+		while (ctx->pos < inode->i_size
+		       && offset < sb->s_blocksize) {
+			de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
+			if (ext4_check_dir_entry(inode, file, de, bh,
+						 bh->b_data, bh->b_size,
+						 offset)) {
+				/*
+				 * On error, skip to the next block
+				 */
+				ctx->pos = (ctx->pos |
+						(sb->s_blocksize - 1)) + 1;
+				break;
+			}
+			offset += ext4_rec_len_from_disk(de->rec_len,
+					sb->s_blocksize);
+			if (le32_to_cpu(de->inode)) {
+				if (!IS_ENCRYPTED(inode)) {
+					if (!dir_emit(ctx, de->name,
+					    de->name_len,
+					    le32_to_cpu(de->inode),
+					    get_dtype(sb, de->file_type)))
+						goto done;
+				} else {
+					int save_len = fstr.len;
+					struct fscrypt_str de_name =
+							FSTR_INIT(de->name,
+								de->name_len);
+
+					/* Directory is encrypted */
+					err = fscrypt_fname_disk_to_usr(inode,
+						0, 0, &de_name, &fstr);
+					de_name = fstr;
+					fstr.len = save_len;
+					if (err)
+						goto errout;
+					if (!dir_emit(ctx,
+					    de_name.name, de_name.len,
+					    le32_to_cpu(de->inode),
+					    get_dtype(sb, de->file_type)))
+						goto done;
+				}
+			}
+			ctx->pos += ext4_rec_len_from_disk(de->rec_len,
+						sb->s_blocksize);
+		}
+		if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
+			goto done;
+		brelse(bh);
+		bh = NULL;
+		offset = 0;
+	}
+done:
+	err = 0;
+errout:
+	fscrypt_fname_free_buffer(&fstr);
+	brelse(bh);
+	return err;
+}
+
+static inline int is_32bit_api(void)
+{
+#ifdef CONFIG_COMPAT
+	return in_compat_syscall();
+#else
+	return (BITS_PER_LONG == 32);
+#endif
+}
+
+/*
+ * These functions convert from the major/minor hash to an f_pos
+ * value for dx directories
+ *
+ * Upper layer (for example NFS) should specify FMODE_32BITHASH or
+ * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
+ * directly on both 32-bit and 64-bit nodes, under such case, neither
+ * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
+ */
+static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return major >> 1;
+	else
+		return ((__u64)(major >> 1) << 32) | (__u64)minor;
+}
+
+static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return (pos << 1) & 0xffffffff;
+	else
+		return ((pos >> 32) << 1) & 0xffffffff;
+}
+
+static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return 0;
+	else
+		return pos & 0xffffffff;
+}
+
+/*
+ * Return 32- or 64-bit end-of-file for dx directories
+ */
+static inline loff_t ext4_get_htree_eof(struct file *filp)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return EXT4_HTREE_EOF_32BIT;
+	else
+		return EXT4_HTREE_EOF_64BIT;
+}
+
+
+/*
+ * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
+ * directories, where the "offset" is in terms of the filename hash
+ * value instead of the byte offset.
+ *
+ * Because we may return a 64-bit hash that is well beyond offset limits,
+ * we need to pass the max hash as the maximum allowable offset in
+ * the htree directory case.
+ *
+ * For non-htree, ext4_llseek already chooses the proper max offset.
+ */
+static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	int dx_dir = is_dx_dir(inode);
+	loff_t ret, htree_max = ext4_get_htree_eof(file);
+
+	if (likely(dx_dir))
+		ret = generic_file_llseek_size(file, offset, whence,
+						    htree_max, htree_max);
+	else
+		ret = ext4_llseek(file, offset, whence);
+	file->f_version = inode_peek_iversion(inode) - 1;
+	return ret;
+}
+
+/*
+ * This structure holds the nodes of the red-black tree used to store
+ * the directory entry in hash order.
+ */
+struct fname {
+	__u32		hash;
+	__u32		minor_hash;
+	struct rb_node	rb_hash;
+	struct fname	*next;
+	__u32		inode;
+	__u8		name_len;
+	__u8		file_type;
+	char		name[];
+};
+
+/*
+ * This functoin implements a non-recursive way of freeing all of the
+ * nodes in the red-black tree.
+ */
+static void free_rb_tree_fname(struct rb_root *root)
+{
+	struct fname *fname, *next;
+
+	rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
+		while (fname) {
+			struct fname *old = fname;
+			fname = fname->next;
+			kfree(old);
+		}
+
+	*root = RB_ROOT;
+}
+
+
+static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
+							   loff_t pos)
+{
+	struct dir_private_info *p;
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return NULL;
+	p->curr_hash = pos2maj_hash(filp, pos);
+	p->curr_minor_hash = pos2min_hash(filp, pos);
+	return p;
+}
+
+void ext4_htree_free_dir_info(struct dir_private_info *p)
+{
+	free_rb_tree_fname(&p->root);
+	kfree(p);
+}
+
+/*
+ * Given a directory entry, enter it into the fname rb tree.
+ *
+ * When filename encryption is enabled, the dirent will hold the
+ * encrypted filename, while the htree will hold decrypted filename.
+ * The decrypted filename is passed in via ent_name.  parameter.
+ */
+int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
+			     __u32 minor_hash,
+			    struct ext4_dir_entry_2 *dirent,
+			    struct fscrypt_str *ent_name)
+{
+	struct rb_node **p, *parent = NULL;
+	struct fname *fname, *new_fn;
+	struct dir_private_info *info;
+	int len;
+
+	info = dir_file->private_data;
+	p = &info->root.rb_node;
+
+	/* Create and allocate the fname structure */
+	len = sizeof(struct fname) + ent_name->len + 1;
+	new_fn = kzalloc(len, GFP_KERNEL);
+	if (!new_fn)
+		return -ENOMEM;
+	new_fn->hash = hash;
+	new_fn->minor_hash = minor_hash;
+	new_fn->inode = le32_to_cpu(dirent->inode);
+	new_fn->name_len = ent_name->len;
+	new_fn->file_type = dirent->file_type;
+	memcpy(new_fn->name, ent_name->name, ent_name->len);
+
+	while (*p) {
+		parent = *p;
+		fname = rb_entry(parent, struct fname, rb_hash);
+
+		/*
+		 * If the hash and minor hash match up, then we put
+		 * them on a linked list.  This rarely happens...
+		 */
+		if ((new_fn->hash == fname->hash) &&
+		    (new_fn->minor_hash == fname->minor_hash)) {
+			new_fn->next = fname->next;
+			fname->next = new_fn;
+			return 0;
+		}
+
+		if (new_fn->hash < fname->hash)
+			p = &(*p)->rb_left;
+		else if (new_fn->hash > fname->hash)
+			p = &(*p)->rb_right;
+		else if (new_fn->minor_hash < fname->minor_hash)
+			p = &(*p)->rb_left;
+		else /* if (new_fn->minor_hash > fname->minor_hash) */
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&new_fn->rb_hash, parent, p);
+	rb_insert_color(&new_fn->rb_hash, &info->root);
+	return 0;
+}
+
+
+
+/*
+ * This is a helper function for ext4_dx_readdir.  It calls filldir
+ * for all entres on the fname linked list.  (Normally there is only
+ * one entry on the linked list, unless there are 62 bit hash collisions.)
+ */
+static int call_filldir(struct file *file, struct dir_context *ctx,
+			struct fname *fname)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+
+	if (!fname) {
+		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
+			 "called with null fname?!?", __func__, __LINE__,
+			 inode->i_ino, current->comm);
+		return 0;
+	}
+	ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
+	while (fname) {
+		if (!dir_emit(ctx, fname->name,
+				fname->name_len,
+				fname->inode,
+				get_dtype(sb, fname->file_type))) {
+			info->extra_fname = fname;
+			return 1;
+		}
+		fname = fname->next;
+	}
+	return 0;
+}
+
+static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct fname *fname;
+	int ret = 0;
+
+	if (!info) {
+		info = ext4_htree_create_dir_info(file, ctx->pos);
+		if (!info)
+			return -ENOMEM;
+		file->private_data = info;
+	}
+
+	if (ctx->pos == ext4_get_htree_eof(file))
+		return 0;	/* EOF */
+
+	/* Some one has messed with f_pos; reset the world */
+	if (info->last_pos != ctx->pos) {
+		free_rb_tree_fname(&info->root);
+		info->curr_node = NULL;
+		info->extra_fname = NULL;
+		info->curr_hash = pos2maj_hash(file, ctx->pos);
+		info->curr_minor_hash = pos2min_hash(file, ctx->pos);
+	}
+
+	/*
+	 * If there are any leftover names on the hash collision
+	 * chain, return them first.
+	 */
+	if (info->extra_fname) {
+		if (call_filldir(file, ctx, info->extra_fname))
+			goto finished;
+		info->extra_fname = NULL;
+		goto next_node;
+	} else if (!info->curr_node)
+		info->curr_node = rb_first(&info->root);
+
+	while (1) {
+		/*
+		 * Fill the rbtree if we have no more entries,
+		 * or the inode has changed since we last read in the
+		 * cached entries.
+		 */
+		if ((!info->curr_node) ||
+		    !inode_eq_iversion(inode, file->f_version)) {
+			info->curr_node = NULL;
+			free_rb_tree_fname(&info->root);
+			file->f_version = inode_query_iversion(inode);
+			ret = ext4_htree_fill_tree(file, info->curr_hash,
+						   info->curr_minor_hash,
+						   &info->next_hash);
+			if (ret < 0)
+				goto finished;
+			if (ret == 0) {
+				ctx->pos = ext4_get_htree_eof(file);
+				break;
+			}
+			info->curr_node = rb_first(&info->root);
+		}
+
+		fname = rb_entry(info->curr_node, struct fname, rb_hash);
+		info->curr_hash = fname->hash;
+		info->curr_minor_hash = fname->minor_hash;
+		if (call_filldir(file, ctx, fname))
+			break;
+	next_node:
+		info->curr_node = rb_next(info->curr_node);
+		if (info->curr_node) {
+			fname = rb_entry(info->curr_node, struct fname,
+					 rb_hash);
+			info->curr_hash = fname->hash;
+			info->curr_minor_hash = fname->minor_hash;
+		} else {
+			if (info->next_hash == ~0) {
+				ctx->pos = ext4_get_htree_eof(file);
+				break;
+			}
+			info->curr_hash = info->next_hash;
+			info->curr_minor_hash = 0;
+		}
+	}
+finished:
+	info->last_pos = ctx->pos;
+	return ret < 0 ? ret : 0;
+}
+
+static int ext4_dir_open(struct inode * inode, struct file * filp)
+{
+	if (IS_ENCRYPTED(inode))
+		return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
+	return 0;
+}
+
+static int ext4_release_dir(struct inode *inode, struct file *filp)
+{
+	if (filp->private_data)
+		ext4_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
+		      int buf_size)
+{
+	struct ext4_dir_entry_2 *de;
+	int rlen;
+	unsigned int offset = 0;
+	char *top;
+
+	de = (struct ext4_dir_entry_2 *)buf;
+	top = buf + buf_size;
+	while ((char *) de < top) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 buf, buf_size, offset))
+			return -EFSCORRUPTED;
+		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
+		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
+		offset += rlen;
+	}
+	if ((char *) de > top)
+		return -EFSCORRUPTED;
+
+	return 0;
+}
+
+const struct file_operations ext4_dir_operations = {
+	.llseek		= ext4_dir_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= ext4_readdir,
+	.unlocked_ioctl = ext4_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext4_compat_ioctl,
+#endif
+	.fsync		= ext4_sync_file,
+	.open		= ext4_dir_open,
+	.release	= ext4_release_dir,
+};
+
+#ifdef CONFIG_UNICODE
+const struct dentry_operations ext4_dentry_ops = {
+	.d_hash = generic_ci_d_hash,
+	.d_compare = generic_ci_d_compare,
+};
+#endif
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
new file mode 100644
index 000000000..fec021e6b
--- /dev/null
+++ b/fs/ext4/ext4.h
@@ -0,0 +1,3709 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  ext4.h
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/include/linux/minix_fs.h
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#ifndef _EXT4_H
+#define _EXT4_H
+
+#include <linux/types.h>
+#include <linux/blkdev.h>
+#include <linux/magic.h>
+#include <linux/jbd2.h>
+#include <linux/quota.h>
+#include <linux/rwsem.h>
+#include <linux/rbtree.h>
+#include <linux/seqlock.h>
+#include <linux/mutex.h>
+#include <linux/timer.h>
+#include <linux/wait.h>
+#include <linux/sched/signal.h>
+#include <linux/blockgroup_lock.h>
+#include <linux/percpu_counter.h>
+#include <linux/ratelimit.h>
+#include <crypto/hash.h>
+#include <linux/falloc.h>
+#include <linux/percpu-rwsem.h>
+#include <linux/fiemap.h>
+#ifdef __KERNEL__
+#include <linux/compat.h>
+#endif
+
+#include <linux/fscrypt.h>
+#include <linux/fsverity.h>
+
+#include <linux/compiler.h>
+
+/*
+ * The fourth extended filesystem constants/structures
+ */
+
+/*
+ * with AGGRESSIVE_CHECK allocator runs consistency checks over
+ * structures. these checks slow things down a lot
+ */
+#define AGGRESSIVE_CHECK__
+
+/*
+ * with DOUBLE_CHECK defined mballoc creates persistent in-core
+ * bitmaps, maintains and uses them to check for double allocations
+ */
+#define DOUBLE_CHECK__
+
+/*
+ * Define EXT4FS_DEBUG to produce debug messages
+ */
+#undef EXT4FS_DEBUG
+
+/*
+ * Debug code
+ */
+#ifdef EXT4FS_DEBUG
+#define ext4_debug(f, a...)						\
+	do {								\
+		printk(KERN_DEBUG "EXT4-fs DEBUG (%s, %d): %s:",	\
+			__FILE__, __LINE__, __func__);			\
+		printk(KERN_DEBUG f, ## a);				\
+	} while (0)
+#else
+#define ext4_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+#endif
+
+ /*
+  * Turn on EXT_DEBUG to enable ext4_ext_show_path/leaf/move in extents.c
+  */
+#define EXT_DEBUG__
+
+/*
+ * Dynamic printk for controlled extents debugging.
+ */
+#ifdef CONFIG_EXT4_DEBUG
+#define ext_debug(ino, fmt, ...)					\
+	pr_debug("[%s/%d] EXT4-fs (%s): ino %lu: (%s, %d): %s:" fmt,	\
+		 current->comm, task_pid_nr(current),			\
+		 ino->i_sb->s_id, ino->i_ino, __FILE__, __LINE__,	\
+		 __func__, ##__VA_ARGS__)
+#else
+#define ext_debug(ino, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+#endif
+
+/* data type for block offset of block group */
+typedef int ext4_grpblk_t;
+
+/* data type for filesystem-wide blocks number */
+typedef unsigned long long ext4_fsblk_t;
+
+/* data type for file logical block number */
+typedef __u32 ext4_lblk_t;
+
+/* data type for block group number */
+typedef unsigned int ext4_group_t;
+
+enum SHIFT_DIRECTION {
+	SHIFT_LEFT = 0,
+	SHIFT_RIGHT,
+};
+
+/*
+ * Flags used in mballoc's allocation_context flags field.
+ *
+ * Also used to show what's going on for debugging purposes when the
+ * flag field is exported via the traceport interface
+ */
+
+/* prefer goal again. length */
+#define EXT4_MB_HINT_MERGE		0x0001
+/* blocks already reserved */
+#define EXT4_MB_HINT_RESERVED		0x0002
+/* metadata is being allocated */
+#define EXT4_MB_HINT_METADATA		0x0004
+/* first blocks in the file */
+#define EXT4_MB_HINT_FIRST		0x0008
+/* search for the best chunk */
+#define EXT4_MB_HINT_BEST		0x0010
+/* data is being allocated */
+#define EXT4_MB_HINT_DATA		0x0020
+/* don't preallocate (for tails) */
+#define EXT4_MB_HINT_NOPREALLOC		0x0040
+/* allocate for locality group */
+#define EXT4_MB_HINT_GROUP_ALLOC	0x0080
+/* allocate goal blocks or none */
+#define EXT4_MB_HINT_GOAL_ONLY		0x0100
+/* goal is meaningful */
+#define EXT4_MB_HINT_TRY_GOAL		0x0200
+/* blocks already pre-reserved by delayed allocation */
+#define EXT4_MB_DELALLOC_RESERVED	0x0400
+/* We are doing stream allocation */
+#define EXT4_MB_STREAM_ALLOC		0x0800
+/* Use reserved root blocks if needed */
+#define EXT4_MB_USE_ROOT_BLOCKS		0x1000
+/* Use blocks from reserved pool */
+#define EXT4_MB_USE_RESERVED		0x2000
+/* Do strict check for free blocks while retrying block allocation */
+#define EXT4_MB_STRICT_CHECK		0x4000
+
+struct ext4_allocation_request {
+	/* target inode for block we're allocating */
+	struct inode *inode;
+	/* how many blocks we want to allocate */
+	unsigned int len;
+	/* logical block in target inode */
+	ext4_lblk_t logical;
+	/* the closest logical allocated block to the left */
+	ext4_lblk_t lleft;
+	/* the closest logical allocated block to the right */
+	ext4_lblk_t lright;
+	/* phys. target (a hint) */
+	ext4_fsblk_t goal;
+	/* phys. block for the closest logical allocated block to the left */
+	ext4_fsblk_t pleft;
+	/* phys. block for the closest logical allocated block to the right */
+	ext4_fsblk_t pright;
+	/* flags. see above EXT4_MB_HINT_* */
+	unsigned int flags;
+};
+
+/*
+ * Logical to physical block mapping, used by ext4_map_blocks()
+ *
+ * This structure is used to pass requests into ext4_map_blocks() as
+ * well as to store the information returned by ext4_map_blocks().  It
+ * takes less room on the stack than a struct buffer_head.
+ */
+#define EXT4_MAP_NEW		BIT(BH_New)
+#define EXT4_MAP_MAPPED		BIT(BH_Mapped)
+#define EXT4_MAP_UNWRITTEN	BIT(BH_Unwritten)
+#define EXT4_MAP_BOUNDARY	BIT(BH_Boundary)
+#define EXT4_MAP_FLAGS		(EXT4_MAP_NEW | EXT4_MAP_MAPPED |\
+				 EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY)
+
+struct ext4_map_blocks {
+	ext4_fsblk_t m_pblk;
+	ext4_lblk_t m_lblk;
+	unsigned int m_len;
+	unsigned int m_flags;
+};
+
+/*
+ * Block validity checking, system zone rbtree.
+ */
+struct ext4_system_blocks {
+	struct rb_root root;
+	struct rcu_head rcu;
+};
+
+/*
+ * Flags for ext4_io_end->flags
+ */
+#define	EXT4_IO_END_UNWRITTEN	0x0001
+
+struct ext4_io_end_vec {
+	struct list_head list;		/* list of io_end_vec */
+	loff_t offset;			/* offset in the file */
+	ssize_t size;			/* size of the extent */
+};
+
+/*
+ * For converting unwritten extents on a work queue. 'handle' is used for
+ * buffered writeback.
+ */
+typedef struct ext4_io_end {
+	struct list_head	list;		/* per-file finished IO list */
+	handle_t		*handle;	/* handle reserved for extent
+						 * conversion */
+	struct inode		*inode;		/* file being written to */
+	struct bio		*bio;		/* Linked list of completed
+						 * bios covering the extent */
+	unsigned int		flag;		/* unwritten or not */
+	atomic_t		count;		/* reference counter */
+	struct list_head	list_vec;	/* list of ext4_io_end_vec */
+} ext4_io_end_t;
+
+struct ext4_io_submit {
+	struct writeback_control *io_wbc;
+	struct bio		*io_bio;
+	ext4_io_end_t		*io_end;
+	sector_t		io_next_block;
+};
+
+/*
+ * Special inodes numbers
+ */
+#define	EXT4_BAD_INO		 1	/* Bad blocks inode */
+#define EXT4_ROOT_INO		 2	/* Root inode */
+#define EXT4_USR_QUOTA_INO	 3	/* User quota inode */
+#define EXT4_GRP_QUOTA_INO	 4	/* Group quota inode */
+#define EXT4_BOOT_LOADER_INO	 5	/* Boot loader inode */
+#define EXT4_UNDEL_DIR_INO	 6	/* Undelete directory inode */
+#define EXT4_RESIZE_INO		 7	/* Reserved group descriptors inode */
+#define EXT4_JOURNAL_INO	 8	/* Journal inode */
+
+/* First non-reserved inode for old ext4 filesystems */
+#define EXT4_GOOD_OLD_FIRST_INO	11
+
+/*
+ * Maximal count of links to a file
+ */
+#define EXT4_LINK_MAX		65000
+
+/*
+ * Macro-instructions used to manage several block sizes
+ */
+#define EXT4_MIN_BLOCK_SIZE		1024
+#define	EXT4_MAX_BLOCK_SIZE		65536
+#define EXT4_MIN_BLOCK_LOG_SIZE		10
+#define EXT4_MAX_BLOCK_LOG_SIZE		16
+#define EXT4_MAX_CLUSTER_LOG_SIZE	30
+#ifdef __KERNEL__
+# define EXT4_BLOCK_SIZE(s)		((s)->s_blocksize)
+#else
+# define EXT4_BLOCK_SIZE(s)		(EXT4_MIN_BLOCK_SIZE << (s)->s_log_block_size)
+#endif
+#define	EXT4_ADDR_PER_BLOCK(s)		(EXT4_BLOCK_SIZE(s) / sizeof(__u32))
+#define EXT4_CLUSTER_SIZE(s)		(EXT4_BLOCK_SIZE(s) << \
+					 EXT4_SB(s)->s_cluster_bits)
+#ifdef __KERNEL__
+# define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)
+# define EXT4_CLUSTER_BITS(s)		(EXT4_SB(s)->s_cluster_bits)
+#else
+# define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)
+#endif
+#ifdef __KERNEL__
+#define	EXT4_ADDR_PER_BLOCK_BITS(s)	(EXT4_SB(s)->s_addr_per_block_bits)
+#define EXT4_INODE_SIZE(s)		(EXT4_SB(s)->s_inode_size)
+#define EXT4_FIRST_INO(s)		(EXT4_SB(s)->s_first_ino)
+#else
+#define EXT4_INODE_SIZE(s)	(((s)->s_rev_level == EXT4_GOOD_OLD_REV) ? \
+				 EXT4_GOOD_OLD_INODE_SIZE : \
+				 (s)->s_inode_size)
+#define EXT4_FIRST_INO(s)	(((s)->s_rev_level == EXT4_GOOD_OLD_REV) ? \
+				 EXT4_GOOD_OLD_FIRST_INO : \
+				 (s)->s_first_ino)
+#endif
+#define EXT4_BLOCK_ALIGN(size, blkbits)		ALIGN((size), (1 << (blkbits)))
+#define EXT4_MAX_BLOCKS(size, offset, blkbits) \
+	((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
+								  blkbits))
+
+/* Translate a block number to a cluster number */
+#define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
+/* Translate a cluster number to a block number */
+#define EXT4_C2B(sbi, cluster)	((cluster) << (sbi)->s_cluster_bits)
+/* Translate # of blks to # of clusters */
+#define EXT4_NUM_B2C(sbi, blks)	(((blks) + (sbi)->s_cluster_ratio - 1) >> \
+				 (sbi)->s_cluster_bits)
+/* Mask out the low bits to get the starting block of the cluster */
+#define EXT4_PBLK_CMASK(s, pblk) ((pblk) &				\
+				  ~((ext4_fsblk_t) (s)->s_cluster_ratio - 1))
+#define EXT4_LBLK_CMASK(s, lblk) ((lblk) &				\
+				  ~((ext4_lblk_t) (s)->s_cluster_ratio - 1))
+/* Fill in the low bits to get the last block of the cluster */
+#define EXT4_LBLK_CFILL(sbi, lblk) ((lblk) |				\
+				    ((ext4_lblk_t) (sbi)->s_cluster_ratio - 1))
+/* Get the cluster offset */
+#define EXT4_PBLK_COFF(s, pblk) ((pblk) &				\
+				 ((ext4_fsblk_t) (s)->s_cluster_ratio - 1))
+#define EXT4_LBLK_COFF(s, lblk) ((lblk) &				\
+				 ((ext4_lblk_t) (s)->s_cluster_ratio - 1))
+
+/*
+ * Structure of a blocks group descriptor
+ */
+struct ext4_group_desc
+{
+	__le32	bg_block_bitmap_lo;	/* Blocks bitmap block */
+	__le32	bg_inode_bitmap_lo;	/* Inodes bitmap block */
+	__le32	bg_inode_table_lo;	/* Inodes table block */
+	__le16	bg_free_blocks_count_lo;/* Free blocks count */
+	__le16	bg_free_inodes_count_lo;/* Free inodes count */
+	__le16	bg_used_dirs_count_lo;	/* Directories count */
+	__le16	bg_flags;		/* EXT4_BG_flags (INODE_UNINIT, etc) */
+	__le32  bg_exclude_bitmap_lo;   /* Exclude bitmap for snapshots */
+	__le16  bg_block_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bbitmap) LE */
+	__le16  bg_inode_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+ibitmap) LE */
+	__le16  bg_itable_unused_lo;	/* Unused inodes count */
+	__le16  bg_checksum;		/* crc16(sb_uuid+group+desc) */
+	__le32	bg_block_bitmap_hi;	/* Blocks bitmap block MSB */
+	__le32	bg_inode_bitmap_hi;	/* Inodes bitmap block MSB */
+	__le32	bg_inode_table_hi;	/* Inodes table block MSB */
+	__le16	bg_free_blocks_count_hi;/* Free blocks count MSB */
+	__le16	bg_free_inodes_count_hi;/* Free inodes count MSB */
+	__le16	bg_used_dirs_count_hi;	/* Directories count MSB */
+	__le16  bg_itable_unused_hi;    /* Unused inodes count MSB */
+	__le32  bg_exclude_bitmap_hi;   /* Exclude bitmap block MSB */
+	__le16  bg_block_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+bbitmap) BE */
+	__le16  bg_inode_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+ibitmap) BE */
+	__u32   bg_reserved;
+};
+
+#define EXT4_BG_INODE_BITMAP_CSUM_HI_END	\
+	(offsetof(struct ext4_group_desc, bg_inode_bitmap_csum_hi) + \
+	 sizeof(__le16))
+#define EXT4_BG_BLOCK_BITMAP_CSUM_HI_END	\
+	(offsetof(struct ext4_group_desc, bg_block_bitmap_csum_hi) + \
+	 sizeof(__le16))
+
+/*
+ * Structure of a flex block group info
+ */
+
+struct flex_groups {
+	atomic64_t	free_clusters;
+	atomic_t	free_inodes;
+	atomic_t	used_dirs;
+};
+
+#define EXT4_BG_INODE_UNINIT	0x0001 /* Inode table/bitmap not in use */
+#define EXT4_BG_BLOCK_UNINIT	0x0002 /* Block bitmap not in use */
+#define EXT4_BG_INODE_ZEROED	0x0004 /* On-disk itable initialized to zero */
+
+/*
+ * Macro-instructions used to manage group descriptors
+ */
+#define EXT4_MIN_DESC_SIZE		32
+#define EXT4_MIN_DESC_SIZE_64BIT	64
+#define	EXT4_MAX_DESC_SIZE		EXT4_MIN_BLOCK_SIZE
+#define EXT4_DESC_SIZE(s)		(EXT4_SB(s)->s_desc_size)
+#ifdef __KERNEL__
+# define EXT4_BLOCKS_PER_GROUP(s)	(EXT4_SB(s)->s_blocks_per_group)
+# define EXT4_CLUSTERS_PER_GROUP(s)	(EXT4_SB(s)->s_clusters_per_group)
+# define EXT4_DESC_PER_BLOCK(s)		(EXT4_SB(s)->s_desc_per_block)
+# define EXT4_INODES_PER_GROUP(s)	(EXT4_SB(s)->s_inodes_per_group)
+# define EXT4_DESC_PER_BLOCK_BITS(s)	(EXT4_SB(s)->s_desc_per_block_bits)
+#else
+# define EXT4_BLOCKS_PER_GROUP(s)	((s)->s_blocks_per_group)
+# define EXT4_DESC_PER_BLOCK(s)		(EXT4_BLOCK_SIZE(s) / EXT4_DESC_SIZE(s))
+# define EXT4_INODES_PER_GROUP(s)	((s)->s_inodes_per_group)
+#endif
+
+/*
+ * Constants relative to the data blocks
+ */
+#define	EXT4_NDIR_BLOCKS		12
+#define	EXT4_IND_BLOCK			EXT4_NDIR_BLOCKS
+#define	EXT4_DIND_BLOCK			(EXT4_IND_BLOCK + 1)
+#define	EXT4_TIND_BLOCK			(EXT4_DIND_BLOCK + 1)
+#define	EXT4_N_BLOCKS			(EXT4_TIND_BLOCK + 1)
+
+/*
+ * Inode flags
+ */
+#define	EXT4_SECRM_FL			0x00000001 /* Secure deletion */
+#define	EXT4_UNRM_FL			0x00000002 /* Undelete */
+#define	EXT4_COMPR_FL			0x00000004 /* Compress file */
+#define EXT4_SYNC_FL			0x00000008 /* Synchronous updates */
+#define EXT4_IMMUTABLE_FL		0x00000010 /* Immutable file */
+#define EXT4_APPEND_FL			0x00000020 /* writes to file may only append */
+#define EXT4_NODUMP_FL			0x00000040 /* do not dump file */
+#define EXT4_NOATIME_FL			0x00000080 /* do not update atime */
+/* Reserved for compression usage... */
+#define EXT4_DIRTY_FL			0x00000100
+#define EXT4_COMPRBLK_FL		0x00000200 /* One or more compressed clusters */
+#define EXT4_NOCOMPR_FL			0x00000400 /* Don't compress */
+	/* nb: was previously EXT2_ECOMPR_FL */
+#define EXT4_ENCRYPT_FL			0x00000800 /* encrypted file */
+/* End compression flags --- maybe not all used */
+#define EXT4_INDEX_FL			0x00001000 /* hash-indexed directory */
+#define EXT4_IMAGIC_FL			0x00002000 /* AFS directory */
+#define EXT4_JOURNAL_DATA_FL		0x00004000 /* file data should be journaled */
+#define EXT4_NOTAIL_FL			0x00008000 /* file tail should not be merged */
+#define EXT4_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
+#define EXT4_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/
+#define EXT4_HUGE_FILE_FL               0x00040000 /* Set to each huge file */
+#define EXT4_EXTENTS_FL			0x00080000 /* Inode uses extents */
+#define EXT4_VERITY_FL			0x00100000 /* Verity protected inode */
+#define EXT4_EA_INODE_FL	        0x00200000 /* Inode used for large EA */
+/* 0x00400000 was formerly EXT4_EOFBLOCKS_FL */
+
+#define EXT4_DAX_FL			0x02000000 /* Inode is DAX */
+
+#define EXT4_INLINE_DATA_FL		0x10000000 /* Inode has inline data. */
+#define EXT4_PROJINHERIT_FL		0x20000000 /* Create with parents projid */
+#define EXT4_CASEFOLD_FL		0x40000000 /* Casefolded directory */
+#define EXT4_RESERVED_FL		0x80000000 /* reserved for ext4 lib */
+
+/* User modifiable flags */
+#define EXT4_FL_USER_MODIFIABLE		(EXT4_SECRM_FL | \
+					 EXT4_UNRM_FL | \
+					 EXT4_COMPR_FL | \
+					 EXT4_SYNC_FL | \
+					 EXT4_IMMUTABLE_FL | \
+					 EXT4_APPEND_FL | \
+					 EXT4_NODUMP_FL | \
+					 EXT4_NOATIME_FL | \
+					 EXT4_JOURNAL_DATA_FL | \
+					 EXT4_NOTAIL_FL | \
+					 EXT4_DIRSYNC_FL | \
+					 EXT4_TOPDIR_FL | \
+					 EXT4_EXTENTS_FL | \
+					 0x00400000 /* EXT4_EOFBLOCKS_FL */ | \
+					 EXT4_DAX_FL | \
+					 EXT4_PROJINHERIT_FL | \
+					 EXT4_CASEFOLD_FL)
+
+/* User visible flags */
+#define EXT4_FL_USER_VISIBLE		(EXT4_FL_USER_MODIFIABLE | \
+					 EXT4_DIRTY_FL | \
+					 EXT4_COMPRBLK_FL | \
+					 EXT4_NOCOMPR_FL | \
+					 EXT4_ENCRYPT_FL | \
+					 EXT4_INDEX_FL | \
+					 EXT4_VERITY_FL | \
+					 EXT4_INLINE_DATA_FL)
+
+/* Flags we can manipulate with through FS_IOC_FSSETXATTR */
+#define EXT4_FL_XFLAG_VISIBLE		(EXT4_SYNC_FL | \
+					 EXT4_IMMUTABLE_FL | \
+					 EXT4_APPEND_FL | \
+					 EXT4_NODUMP_FL | \
+					 EXT4_NOATIME_FL | \
+					 EXT4_PROJINHERIT_FL | \
+					 EXT4_DAX_FL)
+
+/* Flags that should be inherited by new inodes from their parent. */
+#define EXT4_FL_INHERITED (EXT4_SECRM_FL | EXT4_UNRM_FL | EXT4_COMPR_FL |\
+			   EXT4_SYNC_FL | EXT4_NODUMP_FL | EXT4_NOATIME_FL |\
+			   EXT4_NOCOMPR_FL | EXT4_JOURNAL_DATA_FL |\
+			   EXT4_NOTAIL_FL | EXT4_DIRSYNC_FL |\
+			   EXT4_PROJINHERIT_FL | EXT4_CASEFOLD_FL |\
+			   EXT4_DAX_FL)
+
+/* Flags that are appropriate for regular files (all but dir-specific ones). */
+#define EXT4_REG_FLMASK (~(EXT4_DIRSYNC_FL | EXT4_TOPDIR_FL | EXT4_CASEFOLD_FL |\
+			   EXT4_PROJINHERIT_FL))
+
+/* Flags that are appropriate for non-directories/regular files. */
+#define EXT4_OTHER_FLMASK (EXT4_NODUMP_FL | EXT4_NOATIME_FL)
+
+/* The only flags that should be swapped */
+#define EXT4_FL_SHOULD_SWAP (EXT4_HUGE_FILE_FL | EXT4_EXTENTS_FL)
+
+/* Flags which are mutually exclusive to DAX */
+#define EXT4_DAX_MUT_EXCL (EXT4_VERITY_FL | EXT4_ENCRYPT_FL |\
+			   EXT4_JOURNAL_DATA_FL | EXT4_INLINE_DATA_FL)
+
+/* Mask out flags that are inappropriate for the given type of inode. */
+static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
+{
+	if (S_ISDIR(mode))
+		return flags;
+	else if (S_ISREG(mode))
+		return flags & EXT4_REG_FLMASK;
+	else
+		return flags & EXT4_OTHER_FLMASK;
+}
+
+/*
+ * Inode flags used for atomic set/get
+ */
+enum {
+	EXT4_INODE_SECRM	= 0,	/* Secure deletion */
+	EXT4_INODE_UNRM		= 1,	/* Undelete */
+	EXT4_INODE_COMPR	= 2,	/* Compress file */
+	EXT4_INODE_SYNC		= 3,	/* Synchronous updates */
+	EXT4_INODE_IMMUTABLE	= 4,	/* Immutable file */
+	EXT4_INODE_APPEND	= 5,	/* writes to file may only append */
+	EXT4_INODE_NODUMP	= 6,	/* do not dump file */
+	EXT4_INODE_NOATIME	= 7,	/* do not update atime */
+/* Reserved for compression usage... */
+	EXT4_INODE_DIRTY	= 8,
+	EXT4_INODE_COMPRBLK	= 9,	/* One or more compressed clusters */
+	EXT4_INODE_NOCOMPR	= 10,	/* Don't compress */
+	EXT4_INODE_ENCRYPT	= 11,	/* Encrypted file */
+/* End compression flags --- maybe not all used */
+	EXT4_INODE_INDEX	= 12,	/* hash-indexed directory */
+	EXT4_INODE_IMAGIC	= 13,	/* AFS directory */
+	EXT4_INODE_JOURNAL_DATA	= 14,	/* file data should be journaled */
+	EXT4_INODE_NOTAIL	= 15,	/* file tail should not be merged */
+	EXT4_INODE_DIRSYNC	= 16,	/* dirsync behaviour (directories only) */
+	EXT4_INODE_TOPDIR	= 17,	/* Top of directory hierarchies*/
+	EXT4_INODE_HUGE_FILE	= 18,	/* Set to each huge file */
+	EXT4_INODE_EXTENTS	= 19,	/* Inode uses extents */
+	EXT4_INODE_VERITY	= 20,	/* Verity protected inode */
+	EXT4_INODE_EA_INODE	= 21,	/* Inode used for large EA */
+/* 22 was formerly EXT4_INODE_EOFBLOCKS */
+	EXT4_INODE_DAX		= 25,	/* Inode is DAX */
+	EXT4_INODE_INLINE_DATA	= 28,	/* Data in inode. */
+	EXT4_INODE_PROJINHERIT	= 29,	/* Create with parents projid */
+	EXT4_INODE_CASEFOLD	= 30,	/* Casefolded directory */
+	EXT4_INODE_RESERVED	= 31,	/* reserved for ext4 lib */
+};
+
+/*
+ * Since it's pretty easy to mix up bit numbers and hex values, we use a
+ * build-time check to make sure that EXT4_XXX_FL is consistent with respect to
+ * EXT4_INODE_XXX. If all is well, the macros will be dropped, so, it won't cost
+ * any extra space in the compiled kernel image, otherwise, the build will fail.
+ * It's important that these values are the same, since we are using
+ * EXT4_INODE_XXX to test for flag values, but EXT4_XXX_FL must be consistent
+ * with the values of FS_XXX_FL defined in include/linux/fs.h and the on-disk
+ * values found in ext2, ext3 and ext4 filesystems, and of course the values
+ * defined in e2fsprogs.
+ *
+ * It's not paranoia if the Murphy's Law really *is* out to get you.  :-)
+ */
+#define TEST_FLAG_VALUE(FLAG) (EXT4_##FLAG##_FL == (1U << EXT4_INODE_##FLAG))
+#define CHECK_FLAG_VALUE(FLAG) BUILD_BUG_ON(!TEST_FLAG_VALUE(FLAG))
+
+static inline void ext4_check_flag_values(void)
+{
+	CHECK_FLAG_VALUE(SECRM);
+	CHECK_FLAG_VALUE(UNRM);
+	CHECK_FLAG_VALUE(COMPR);
+	CHECK_FLAG_VALUE(SYNC);
+	CHECK_FLAG_VALUE(IMMUTABLE);
+	CHECK_FLAG_VALUE(APPEND);
+	CHECK_FLAG_VALUE(NODUMP);
+	CHECK_FLAG_VALUE(NOATIME);
+	CHECK_FLAG_VALUE(DIRTY);
+	CHECK_FLAG_VALUE(COMPRBLK);
+	CHECK_FLAG_VALUE(NOCOMPR);
+	CHECK_FLAG_VALUE(ENCRYPT);
+	CHECK_FLAG_VALUE(INDEX);
+	CHECK_FLAG_VALUE(IMAGIC);
+	CHECK_FLAG_VALUE(JOURNAL_DATA);
+	CHECK_FLAG_VALUE(NOTAIL);
+	CHECK_FLAG_VALUE(DIRSYNC);
+	CHECK_FLAG_VALUE(TOPDIR);
+	CHECK_FLAG_VALUE(HUGE_FILE);
+	CHECK_FLAG_VALUE(EXTENTS);
+	CHECK_FLAG_VALUE(VERITY);
+	CHECK_FLAG_VALUE(EA_INODE);
+	CHECK_FLAG_VALUE(INLINE_DATA);
+	CHECK_FLAG_VALUE(PROJINHERIT);
+	CHECK_FLAG_VALUE(CASEFOLD);
+	CHECK_FLAG_VALUE(RESERVED);
+}
+
+/* Used to pass group descriptor data when online resize is done */
+struct ext4_new_group_input {
+	__u32 group;		/* Group number for this data */
+	__u64 block_bitmap;	/* Absolute block number of block bitmap */
+	__u64 inode_bitmap;	/* Absolute block number of inode bitmap */
+	__u64 inode_table;	/* Absolute block number of inode table start */
+	__u32 blocks_count;	/* Total number of blocks in this group */
+	__u16 reserved_blocks;	/* Number of reserved blocks in this group */
+	__u16 unused;
+};
+
+#if defined(__KERNEL__) && defined(CONFIG_COMPAT)
+struct compat_ext4_new_group_input {
+	u32 group;
+	compat_u64 block_bitmap;
+	compat_u64 inode_bitmap;
+	compat_u64 inode_table;
+	u32 blocks_count;
+	u16 reserved_blocks;
+	u16 unused;
+};
+#endif
+
+/* The struct ext4_new_group_input in kernel space, with free_blocks_count */
+struct ext4_new_group_data {
+	__u32 group;
+	__u64 block_bitmap;
+	__u64 inode_bitmap;
+	__u64 inode_table;
+	__u32 blocks_count;
+	__u16 reserved_blocks;
+	__u16 mdata_blocks;
+	__u32 free_clusters_count;
+};
+
+/* Indexes used to index group tables in ext4_new_group_data */
+enum {
+	BLOCK_BITMAP = 0,	/* block bitmap */
+	INODE_BITMAP,		/* inode bitmap */
+	INODE_TABLE,		/* inode tables */
+	GROUP_TABLE_COUNT,
+};
+
+/*
+ * Flags used by ext4_map_blocks()
+ */
+	/* Allocate any needed blocks and/or convert an unwritten
+	   extent to be an initialized ext4 */
+#define EXT4_GET_BLOCKS_CREATE			0x0001
+	/* Request the creation of an unwritten extent */
+#define EXT4_GET_BLOCKS_UNWRIT_EXT		0x0002
+#define EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT	(EXT4_GET_BLOCKS_UNWRIT_EXT|\
+						 EXT4_GET_BLOCKS_CREATE)
+	/* Caller is from the delayed allocation writeout path
+	 * finally doing the actual allocation of delayed blocks */
+#define EXT4_GET_BLOCKS_DELALLOC_RESERVE	0x0004
+	/* caller is from the direct IO path, request to creation of an
+	unwritten extents if not allocated, split the unwritten
+	extent if blocks has been preallocated already*/
+#define EXT4_GET_BLOCKS_PRE_IO			0x0008
+#define EXT4_GET_BLOCKS_CONVERT			0x0010
+#define EXT4_GET_BLOCKS_IO_CREATE_EXT		(EXT4_GET_BLOCKS_PRE_IO|\
+					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)
+	/* Convert extent to initialized after IO complete */
+#define EXT4_GET_BLOCKS_IO_CONVERT_EXT		(EXT4_GET_BLOCKS_CONVERT|\
+					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)
+	/* Eventual metadata allocation (due to growing extent tree)
+	 * should not fail, so try to use reserved blocks for that.*/
+#define EXT4_GET_BLOCKS_METADATA_NOFAIL		0x0020
+	/* Don't normalize allocation size (used for fallocate) */
+#define EXT4_GET_BLOCKS_NO_NORMALIZE		0x0040
+	/* Convert written extents to unwritten */
+#define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN	0x0100
+	/* Write zeros to newly created written extents */
+#define EXT4_GET_BLOCKS_ZERO			0x0200
+#define EXT4_GET_BLOCKS_CREATE_ZERO		(EXT4_GET_BLOCKS_CREATE |\
+					EXT4_GET_BLOCKS_ZERO)
+	/* Caller will submit data before dropping transaction handle. This
+	 * allows jbd2 to avoid submitting data before commit. */
+#define EXT4_GET_BLOCKS_IO_SUBMIT		0x0400
+
+/*
+ * The bit position of these flags must not overlap with any of the
+ * EXT4_GET_BLOCKS_*.  They are used by ext4_find_extent(),
+ * read_extent_tree_block(), ext4_split_extent_at(),
+ * ext4_ext_insert_extent(), and ext4_ext_create_new_leaf().
+ * EXT4_EX_NOCACHE is used to indicate that the we shouldn't be
+ * caching the extents when reading from the extent tree while a
+ * truncate or punch hole operation is in progress.
+ */
+#define EXT4_EX_NOCACHE				0x40000000
+#define EXT4_EX_FORCE_CACHE			0x20000000
+#define EXT4_EX_NOFAIL				0x10000000
+
+/*
+ * Flags used by ext4_free_blocks
+ */
+#define EXT4_FREE_BLOCKS_METADATA		0x0001
+#define EXT4_FREE_BLOCKS_FORGET			0x0002
+#define EXT4_FREE_BLOCKS_VALIDATED		0x0004
+#define EXT4_FREE_BLOCKS_NO_QUOT_UPDATE		0x0008
+#define EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER	0x0010
+#define EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER	0x0020
+#define EXT4_FREE_BLOCKS_RERESERVE_CLUSTER      0x0040
+
+/*
+ * ioctl commands
+ */
+#define	EXT4_IOC_GETVERSION		_IOR('f', 3, long)
+#define	EXT4_IOC_SETVERSION		_IOW('f', 4, long)
+#define	EXT4_IOC_GETVERSION_OLD		FS_IOC_GETVERSION
+#define	EXT4_IOC_SETVERSION_OLD		FS_IOC_SETVERSION
+#define EXT4_IOC_GETRSVSZ		_IOR('f', 5, long)
+#define EXT4_IOC_SETRSVSZ		_IOW('f', 6, long)
+#define EXT4_IOC_GROUP_EXTEND		_IOW('f', 7, unsigned long)
+#define EXT4_IOC_GROUP_ADD		_IOW('f', 8, struct ext4_new_group_input)
+#define EXT4_IOC_MIGRATE		_IO('f', 9)
+ /* note ioctl 10 reserved for an early version of the FIEMAP ioctl */
+ /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
+#define EXT4_IOC_ALLOC_DA_BLKS		_IO('f', 12)
+#define EXT4_IOC_MOVE_EXT		_IOWR('f', 15, struct move_extent)
+#define EXT4_IOC_RESIZE_FS		_IOW('f', 16, __u64)
+#define EXT4_IOC_SWAP_BOOT		_IO('f', 17)
+#define EXT4_IOC_PRECACHE_EXTENTS	_IO('f', 18)
+/* ioctl codes 19--39 are reserved for fscrypt */
+#define EXT4_IOC_CLEAR_ES_CACHE		_IO('f', 40)
+#define EXT4_IOC_GETSTATE		_IOW('f', 41, __u32)
+#define EXT4_IOC_GET_ES_CACHE		_IOWR('f', 42, struct fiemap)
+
+#define EXT4_IOC_SHUTDOWN _IOR ('X', 125, __u32)
+
+/*
+ * Flags for going down operation
+ */
+#define EXT4_GOING_FLAGS_DEFAULT		0x0	/* going down */
+#define EXT4_GOING_FLAGS_LOGFLUSH		0x1	/* flush log but not data */
+#define EXT4_GOING_FLAGS_NOLOGFLUSH		0x2	/* don't flush log nor data */
+
+/*
+ * Flags returned by EXT4_IOC_GETSTATE
+ *
+ * We only expose to userspace a subset of the state flags in
+ * i_state_flags
+ */
+#define EXT4_STATE_FLAG_EXT_PRECACHED	0x00000001
+#define EXT4_STATE_FLAG_NEW		0x00000002
+#define EXT4_STATE_FLAG_NEWENTRY	0x00000004
+#define EXT4_STATE_FLAG_DA_ALLOC_CLOSE	0x00000008
+
+#if defined(__KERNEL__) && defined(CONFIG_COMPAT)
+/*
+ * ioctl commands in 32 bit emulation
+ */
+#define EXT4_IOC32_GETVERSION		_IOR('f', 3, int)
+#define EXT4_IOC32_SETVERSION		_IOW('f', 4, int)
+#define EXT4_IOC32_GETRSVSZ		_IOR('f', 5, int)
+#define EXT4_IOC32_SETRSVSZ		_IOW('f', 6, int)
+#define EXT4_IOC32_GROUP_EXTEND		_IOW('f', 7, unsigned int)
+#define EXT4_IOC32_GROUP_ADD		_IOW('f', 8, struct compat_ext4_new_group_input)
+#define EXT4_IOC32_GETVERSION_OLD	FS_IOC32_GETVERSION
+#define EXT4_IOC32_SETVERSION_OLD	FS_IOC32_SETVERSION
+#endif
+
+/*
+ * Returned by EXT4_IOC_GET_ES_CACHE as an additional possible flag.
+ * It indicates that the entry in extent status cache is for a hole.
+ */
+#define EXT4_FIEMAP_EXTENT_HOLE		0x08000000
+
+/* Max physical block we can address w/o extents */
+#define EXT4_MAX_BLOCK_FILE_PHYS	0xFFFFFFFF
+
+/* Max logical block we can support */
+#define EXT4_MAX_LOGICAL_BLOCK		0xFFFFFFFE
+
+/*
+ * Structure of an inode on the disk
+ */
+struct ext4_inode {
+	__le16	i_mode;		/* File mode */
+	__le16	i_uid;		/* Low 16 bits of Owner Uid */
+	__le32	i_size_lo;	/* Size in bytes */
+	__le32	i_atime;	/* Access time */
+	__le32	i_ctime;	/* Inode Change time */
+	__le32	i_mtime;	/* Modification time */
+	__le32	i_dtime;	/* Deletion Time */
+	__le16	i_gid;		/* Low 16 bits of Group Id */
+	__le16	i_links_count;	/* Links count */
+	__le32	i_blocks_lo;	/* Blocks count */
+	__le32	i_flags;	/* File flags */
+	union {
+		struct {
+			__le32  l_i_version;
+		} linux1;
+		struct {
+			__u32  h_i_translator;
+		} hurd1;
+		struct {
+			__u32  m_i_reserved1;
+		} masix1;
+	} osd1;				/* OS dependent 1 */
+	__le32	i_block[EXT4_N_BLOCKS];/* Pointers to blocks */
+	__le32	i_generation;	/* File version (for NFS) */
+	__le32	i_file_acl_lo;	/* File ACL */
+	__le32	i_size_high;
+	__le32	i_obso_faddr;	/* Obsoleted fragment address */
+	union {
+		struct {
+			__le16	l_i_blocks_high; /* were l_i_reserved1 */
+			__le16	l_i_file_acl_high;
+			__le16	l_i_uid_high;	/* these 2 fields */
+			__le16	l_i_gid_high;	/* were reserved2[0] */
+			__le16	l_i_checksum_lo;/* crc32c(uuid+inum+inode) LE */
+			__le16	l_i_reserved;
+		} linux2;
+		struct {
+			__le16	h_i_reserved1;	/* Obsoleted fragment number/size which are removed in ext4 */
+			__u16	h_i_mode_high;
+			__u16	h_i_uid_high;
+			__u16	h_i_gid_high;
+			__u32	h_i_author;
+		} hurd2;
+		struct {
+			__le16	h_i_reserved1;	/* Obsoleted fragment number/size which are removed in ext4 */
+			__le16	m_i_file_acl_high;
+			__u32	m_i_reserved2[2];
+		} masix2;
+	} osd2;				/* OS dependent 2 */
+	__le16	i_extra_isize;
+	__le16	i_checksum_hi;	/* crc32c(uuid+inum+inode) BE */
+	__le32  i_ctime_extra;  /* extra Change time      (nsec << 2 | epoch) */
+	__le32  i_mtime_extra;  /* extra Modification time(nsec << 2 | epoch) */
+	__le32  i_atime_extra;  /* extra Access time      (nsec << 2 | epoch) */
+	__le32  i_crtime;       /* File Creation time */
+	__le32  i_crtime_extra; /* extra FileCreationtime (nsec << 2 | epoch) */
+	__le32  i_version_hi;	/* high 32 bits for 64-bit version */
+	__le32	i_projid;	/* Project ID */
+};
+
+struct move_extent {
+	__u32 reserved;		/* should be zero */
+	__u32 donor_fd;		/* donor file descriptor */
+	__u64 orig_start;	/* logical start offset in block for orig */
+	__u64 donor_start;	/* logical start offset in block for donor */
+	__u64 len;		/* block length to be moved */
+	__u64 moved_len;	/* moved block length */
+};
+
+#define EXT4_EPOCH_BITS 2
+#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
+#define EXT4_NSEC_MASK  (~0UL << EXT4_EPOCH_BITS)
+
+/*
+ * Extended fields will fit into an inode if the filesystem was formatted
+ * with large inodes (-I 256 or larger) and there are not currently any EAs
+ * consuming all of the available space. For new inodes we always reserve
+ * enough space for the kernel's known extended fields, but for inodes
+ * created with an old kernel this might not have been the case. None of
+ * the extended inode fields is critical for correct filesystem operation.
+ * This macro checks if a certain field fits in the inode. Note that
+ * inode-size = GOOD_OLD_INODE_SIZE + i_extra_isize
+ */
+#define EXT4_FITS_IN_INODE(ext4_inode, einode, field)	\
+	((offsetof(typeof(*ext4_inode), field) +	\
+	  sizeof((ext4_inode)->field))			\
+	<= (EXT4_GOOD_OLD_INODE_SIZE +			\
+	    (einode)->i_extra_isize))			\
+
+/*
+ * We use an encoding that preserves the times for extra epoch "00":
+ *
+ * extra  msb of                         adjust for signed
+ * epoch  32-bit                         32-bit tv_sec to
+ * bits   time    decoded 64-bit tv_sec  64-bit tv_sec      valid time range
+ * 0 0    1    -0x80000000..-0x00000001  0x000000000 1901-12-13..1969-12-31
+ * 0 0    0    0x000000000..0x07fffffff  0x000000000 1970-01-01..2038-01-19
+ * 0 1    1    0x080000000..0x0ffffffff  0x100000000 2038-01-19..2106-02-07
+ * 0 1    0    0x100000000..0x17fffffff  0x100000000 2106-02-07..2174-02-25
+ * 1 0    1    0x180000000..0x1ffffffff  0x200000000 2174-02-25..2242-03-16
+ * 1 0    0    0x200000000..0x27fffffff  0x200000000 2242-03-16..2310-04-04
+ * 1 1    1    0x280000000..0x2ffffffff  0x300000000 2310-04-04..2378-04-22
+ * 1 1    0    0x300000000..0x37fffffff  0x300000000 2378-04-22..2446-05-10
+ *
+ * Note that previous versions of the kernel on 64-bit systems would
+ * incorrectly use extra epoch bits 1,1 for dates between 1901 and
+ * 1970.  e2fsck will correct this, assuming that it is run on the
+ * affected filesystem before 2242.
+ */
+
+static inline __le32 ext4_encode_extra_time(struct timespec64 *time)
+{
+	u32 extra =((time->tv_sec - (s32)time->tv_sec) >> 32) & EXT4_EPOCH_MASK;
+	return cpu_to_le32(extra | (time->tv_nsec << EXT4_EPOCH_BITS));
+}
+
+static inline void ext4_decode_extra_time(struct timespec64 *time,
+					  __le32 extra)
+{
+	if (unlikely(extra & cpu_to_le32(EXT4_EPOCH_MASK)))
+		time->tv_sec += (u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK) << 32;
+	time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> EXT4_EPOCH_BITS;
+}
+
+#define EXT4_INODE_SET_XTIME(xtime, inode, raw_inode)				\
+do {										\
+	if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra))     {\
+		(raw_inode)->xtime = cpu_to_le32((inode)->xtime.tv_sec);	\
+		(raw_inode)->xtime ## _extra =					\
+				ext4_encode_extra_time(&(inode)->xtime);	\
+		}								\
+	else	\
+		(raw_inode)->xtime = cpu_to_le32(clamp_t(int32_t, (inode)->xtime.tv_sec, S32_MIN, S32_MAX));	\
+} while (0)
+
+#define EXT4_EINODE_SET_XTIME(xtime, einode, raw_inode)			       \
+do {									       \
+	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime))		       \
+		(raw_inode)->xtime = cpu_to_le32((einode)->xtime.tv_sec);      \
+	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra))	       \
+		(raw_inode)->xtime ## _extra =				       \
+				ext4_encode_extra_time(&(einode)->xtime);      \
+} while (0)
+
+#define EXT4_INODE_GET_XTIME(xtime, inode, raw_inode)				\
+do {										\
+	(inode)->xtime.tv_sec = (signed)le32_to_cpu((raw_inode)->xtime);	\
+	if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra)) {	\
+		ext4_decode_extra_time(&(inode)->xtime,				\
+				       raw_inode->xtime ## _extra);		\
+		}								\
+	else									\
+		(inode)->xtime.tv_nsec = 0;					\
+} while (0)
+
+
+#define EXT4_EINODE_GET_XTIME(xtime, einode, raw_inode)			       \
+do {									       \
+	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime))		       \
+		(einode)->xtime.tv_sec = 				       \
+			(signed)le32_to_cpu((raw_inode)->xtime);	       \
+	else								       \
+		(einode)->xtime.tv_sec = 0;				       \
+	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra))	       \
+		ext4_decode_extra_time(&(einode)->xtime,		       \
+				       raw_inode->xtime ## _extra);	       \
+	else								       \
+		(einode)->xtime.tv_nsec = 0;				       \
+} while (0)
+
+#define i_disk_version osd1.linux1.l_i_version
+
+#if defined(__KERNEL__) || defined(__linux__)
+#define i_reserved1	osd1.linux1.l_i_reserved1
+#define i_file_acl_high	osd2.linux2.l_i_file_acl_high
+#define i_blocks_high	osd2.linux2.l_i_blocks_high
+#define i_uid_low	i_uid
+#define i_gid_low	i_gid
+#define i_uid_high	osd2.linux2.l_i_uid_high
+#define i_gid_high	osd2.linux2.l_i_gid_high
+#define i_checksum_lo	osd2.linux2.l_i_checksum_lo
+
+#elif defined(__GNU__)
+
+#define i_translator	osd1.hurd1.h_i_translator
+#define i_uid_high	osd2.hurd2.h_i_uid_high
+#define i_gid_high	osd2.hurd2.h_i_gid_high
+#define i_author	osd2.hurd2.h_i_author
+
+#elif defined(__masix__)
+
+#define i_reserved1	osd1.masix1.m_i_reserved1
+#define i_file_acl_high	osd2.masix2.m_i_file_acl_high
+#define i_reserved2	osd2.masix2.m_i_reserved2
+
+#endif /* defined(__KERNEL__) || defined(__linux__) */
+
+#include "extents_status.h"
+#include "fast_commit.h"
+
+/*
+ * Lock subclasses for i_data_sem in the ext4_inode_info structure.
+ *
+ * These are needed to avoid lockdep false positives when we need to
+ * allocate blocks to the quota inode during ext4_map_blocks(), while
+ * holding i_data_sem for a normal (non-quota) inode.  Since we don't
+ * do quota tracking for the quota inode, this avoids deadlock (as
+ * well as infinite recursion, since it isn't turtles all the way
+ * down...)
+ *
+ *  I_DATA_SEM_NORMAL - Used for most inodes
+ *  I_DATA_SEM_OTHER  - Used by move_inode.c for the second normal inode
+ *			  where the second inode has larger inode number
+ *			  than the first
+ *  I_DATA_SEM_QUOTA  - Used for quota inodes only
+ *  I_DATA_SEM_EA     - Used for ea_inodes only
+ */
+enum {
+	I_DATA_SEM_NORMAL = 0,
+	I_DATA_SEM_OTHER,
+	I_DATA_SEM_QUOTA,
+	I_DATA_SEM_EA
+};
+
+
+/*
+ * fourth extended file system inode data in memory
+ */
+struct ext4_inode_info {
+	__le32	i_data[15];	/* unconverted */
+	__u32	i_dtime;
+	ext4_fsblk_t	i_file_acl;
+
+	/*
+	 * i_block_group is the number of the block group which contains
+	 * this file's inode.  Constant across the lifetime of the inode,
+	 * it is used for making block allocation decisions - we try to
+	 * place a file's data blocks near its inode block, and new inodes
+	 * near to their parent directory's inode.
+	 */
+	ext4_group_t	i_block_group;
+	ext4_lblk_t	i_dir_start_lookup;
+#if (BITS_PER_LONG < 64)
+	unsigned long	i_state_flags;		/* Dynamic state flags */
+#endif
+	unsigned long	i_flags;
+
+	/*
+	 * Extended attributes can be read independently of the main file
+	 * data. Taking i_mutex even when reading would cause contention
+	 * between readers of EAs and writers of regular file data, so
+	 * instead we synchronize on xattr_sem when reading or changing
+	 * EAs.
+	 */
+	struct rw_semaphore xattr_sem;
+
+	struct list_head i_orphan;	/* unlinked but open inodes */
+
+	/* Fast commit related info */
+
+	struct list_head i_fc_list;	/*
+					 * inodes that need fast commit
+					 * protected by sbi->s_fc_lock.
+					 */
+
+	/* Start of lblk range that needs to be committed in this fast commit */
+	ext4_lblk_t i_fc_lblk_start;
+
+	/* End of lblk range that needs to be committed in this fast commit */
+	ext4_lblk_t i_fc_lblk_len;
+
+	/* Number of ongoing updates on this inode */
+	atomic_t  i_fc_updates;
+
+	/* Fast commit wait queue for this inode */
+	wait_queue_head_t i_fc_wait;
+
+	/* Protect concurrent accesses on i_fc_lblk_start, i_fc_lblk_len */
+	struct mutex i_fc_lock;
+
+	/*
+	 * i_disksize keeps track of what the inode size is ON DISK, not
+	 * in memory.  During truncate, i_size is set to the new size by
+	 * the VFS prior to calling ext4_truncate(), but the filesystem won't
+	 * set i_disksize to 0 until the truncate is actually under way.
+	 *
+	 * The intent is that i_disksize always represents the blocks which
+	 * are used by this file.  This allows recovery to restart truncate
+	 * on orphans if we crash during truncate.  We actually write i_disksize
+	 * into the on-disk inode when writing inodes out, instead of i_size.
+	 *
+	 * The only time when i_disksize and i_size may be different is when
+	 * a truncate is in progress.  The only things which change i_disksize
+	 * are ext4_get_block (growth) and ext4_truncate (shrinkth).
+	 */
+	loff_t	i_disksize;
+
+	/*
+	 * i_data_sem is for serialising ext4_truncate() against
+	 * ext4_getblock().  In the 2.4 ext2 design, great chunks of inode's
+	 * data tree are chopped off during truncate. We can't do that in
+	 * ext4 because whenever we perform intermediate commits during
+	 * truncate, the inode and all the metadata blocks *must* be in a
+	 * consistent state which allows truncation of the orphans to restart
+	 * during recovery.  Hence we must fix the get_block-vs-truncate race
+	 * by other means, so we have i_data_sem.
+	 */
+	struct rw_semaphore i_data_sem;
+	/*
+	 * i_mmap_sem is for serializing page faults with truncate / punch hole
+	 * operations. We have to make sure that new page cannot be faulted in
+	 * a section of the inode that is being punched. We cannot easily use
+	 * i_data_sem for this since we need protection for the whole punch
+	 * operation and i_data_sem ranks below transaction start so we have
+	 * to occasionally drop it.
+	 */
+	struct rw_semaphore i_mmap_sem;
+	struct inode vfs_inode;
+	struct jbd2_inode *jinode;
+
+	spinlock_t i_raw_lock;	/* protects updates to the raw inode */
+
+	/*
+	 * File creation time. Its function is same as that of
+	 * struct timespec64 i_{a,c,m}time in the generic inode.
+	 */
+	struct timespec64 i_crtime;
+
+	/* mballoc */
+	atomic_t i_prealloc_active;
+	struct list_head i_prealloc_list;
+	spinlock_t i_prealloc_lock;
+
+	/* extents status tree */
+	struct ext4_es_tree i_es_tree;
+	rwlock_t i_es_lock;
+	struct list_head i_es_list;
+	unsigned int i_es_all_nr;	/* protected by i_es_lock */
+	unsigned int i_es_shk_nr;	/* protected by i_es_lock */
+	ext4_lblk_t i_es_shrink_lblk;	/* Offset where we start searching for
+					   extents to shrink. Protected by
+					   i_es_lock  */
+
+	/* ialloc */
+	ext4_group_t	i_last_alloc_group;
+
+	/* allocation reservation info for delalloc */
+	/* In case of bigalloc, this refer to clusters rather than blocks */
+	unsigned int i_reserved_data_blocks;
+
+	/* pending cluster reservations for bigalloc file systems */
+	struct ext4_pending_tree i_pending_tree;
+
+	/* on-disk additional length */
+	__u16 i_extra_isize;
+
+	/* Indicate the inline data space. */
+	u16 i_inline_off;
+	u16 i_inline_size;
+
+#ifdef CONFIG_QUOTA
+	/* quota space reservation, managed internally by quota code */
+	qsize_t i_reserved_quota;
+#endif
+
+	/* Lock protecting lists below */
+	spinlock_t i_completed_io_lock;
+	/*
+	 * Completed IOs that need unwritten extents handling and have
+	 * transaction reserved
+	 */
+	struct list_head i_rsv_conversion_list;
+	struct work_struct i_rsv_conversion_work;
+	atomic_t i_unwritten; /* Nr. of inflight conversions pending */
+
+	spinlock_t i_block_reservation_lock;
+
+	/*
+	 * Transactions that contain inode's metadata needed to complete
+	 * fsync and fdatasync, respectively.
+	 */
+	tid_t i_sync_tid;
+	tid_t i_datasync_tid;
+
+#ifdef CONFIG_QUOTA
+	struct dquot *i_dquot[MAXQUOTAS];
+#endif
+
+	/* Precomputed uuid+inum+igen checksum for seeding inode checksums */
+	__u32 i_csum_seed;
+
+	kprojid_t i_projid;
+};
+
+/*
+ * File system states
+ */
+#define	EXT4_VALID_FS			0x0001	/* Unmounted cleanly */
+#define	EXT4_ERROR_FS			0x0002	/* Errors detected */
+#define	EXT4_ORPHAN_FS			0x0004	/* Orphans being recovered */
+#define EXT4_FC_REPLAY			0x0020	/* Fast commit replay ongoing */
+
+/*
+ * Misc. filesystem flags
+ */
+#define EXT2_FLAGS_SIGNED_HASH		0x0001  /* Signed dirhash in use */
+#define EXT2_FLAGS_UNSIGNED_HASH	0x0002  /* Unsigned dirhash in use */
+#define EXT2_FLAGS_TEST_FILESYS		0x0004	/* to test development code */
+
+/*
+ * Mount flags set via mount options or defaults
+ */
+#define EXT4_MOUNT_NO_MBCACHE		0x00001 /* Do not use mbcache */
+#define EXT4_MOUNT_GRPID		0x00004	/* Create files with directory's group */
+#define EXT4_MOUNT_DEBUG		0x00008	/* Some debugging messages */
+#define EXT4_MOUNT_ERRORS_CONT		0x00010	/* Continue on errors */
+#define EXT4_MOUNT_ERRORS_RO		0x00020	/* Remount fs ro on errors */
+#define EXT4_MOUNT_ERRORS_PANIC		0x00040	/* Panic on errors */
+#define EXT4_MOUNT_ERRORS_MASK		0x00070
+#define EXT4_MOUNT_MINIX_DF		0x00080	/* Mimics the Minix statfs */
+#define EXT4_MOUNT_NOLOAD		0x00100	/* Don't use existing journal*/
+#ifdef CONFIG_FS_DAX
+#define EXT4_MOUNT_DAX_ALWAYS		0x00200	/* Direct Access */
+#else
+#define EXT4_MOUNT_DAX_ALWAYS		0
+#endif
+#define EXT4_MOUNT_DATA_FLAGS		0x00C00	/* Mode for data writes: */
+#define EXT4_MOUNT_JOURNAL_DATA		0x00400	/* Write data to journal */
+#define EXT4_MOUNT_ORDERED_DATA		0x00800	/* Flush data before commit */
+#define EXT4_MOUNT_WRITEBACK_DATA	0x00C00	/* No data ordering */
+#define EXT4_MOUNT_UPDATE_JOURNAL	0x01000	/* Update the journal format */
+#define EXT4_MOUNT_NO_UID32		0x02000  /* Disable 32-bit UIDs */
+#define EXT4_MOUNT_XATTR_USER		0x04000	/* Extended user attributes */
+#define EXT4_MOUNT_POSIX_ACL		0x08000	/* POSIX Access Control Lists */
+#define EXT4_MOUNT_NO_AUTO_DA_ALLOC	0x10000	/* No auto delalloc mapping */
+#define EXT4_MOUNT_BARRIER		0x20000 /* Use block barriers */
+#define EXT4_MOUNT_QUOTA		0x40000 /* Some quota option set */
+#define EXT4_MOUNT_USRQUOTA		0x80000 /* "old" user quota,
+						 * enable enforcement for hidden
+						 * quota files */
+#define EXT4_MOUNT_GRPQUOTA		0x100000 /* "old" group quota, enable
+						  * enforcement for hidden quota
+						  * files */
+#define EXT4_MOUNT_PRJQUOTA		0x200000 /* Enable project quota
+						  * enforcement */
+#define EXT4_MOUNT_DIOREAD_NOLOCK	0x400000 /* Enable support for dio read nolocking */
+#define EXT4_MOUNT_JOURNAL_CHECKSUM	0x800000 /* Journal checksums */
+#define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT	0x1000000 /* Journal Async Commit */
+#define EXT4_MOUNT_WARN_ON_ERROR	0x2000000 /* Trigger WARN_ON on error */
+#define EXT4_MOUNT_PREFETCH_BLOCK_BITMAPS 0x4000000
+#define EXT4_MOUNT_DELALLOC		0x8000000 /* Delalloc support */
+#define EXT4_MOUNT_DATA_ERR_ABORT	0x10000000 /* Abort on file data write */
+#define EXT4_MOUNT_BLOCK_VALIDITY	0x20000000 /* Block validity checking */
+#define EXT4_MOUNT_DISCARD		0x40000000 /* Issue DISCARD requests */
+#define EXT4_MOUNT_INIT_INODE_TABLE	0x80000000 /* Initialize uninitialized itables */
+
+/*
+ * Mount flags set either automatically (could not be set by mount option)
+ * based on per file system feature or property or in special cases such as
+ * distinguishing between explicit mount option definition and default.
+ */
+#define EXT4_MOUNT2_EXPLICIT_DELALLOC	0x00000001 /* User explicitly
+						      specified delalloc */
+#define EXT4_MOUNT2_STD_GROUP_SIZE	0x00000002 /* We have standard group
+						      size of blocksize * 8
+						      blocks */
+#define EXT4_MOUNT2_HURD_COMPAT		0x00000004 /* Support HURD-castrated
+						      file systems */
+#define EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM	0x00000008 /* User explicitly
+						specified journal checksum */
+
+#define EXT4_MOUNT2_JOURNAL_FAST_COMMIT	0x00000010 /* Journal fast commit */
+#define EXT4_MOUNT2_DAX_NEVER		0x00000020 /* Do not allow Direct Access */
+#define EXT4_MOUNT2_DAX_INODE		0x00000040 /* For printing options only */
+
+
+#define clear_opt(sb, opt)		EXT4_SB(sb)->s_mount_opt &= \
+						~EXT4_MOUNT_##opt
+#define set_opt(sb, opt)		EXT4_SB(sb)->s_mount_opt |= \
+						EXT4_MOUNT_##opt
+#define test_opt(sb, opt)		(EXT4_SB(sb)->s_mount_opt & \
+					 EXT4_MOUNT_##opt)
+
+#define clear_opt2(sb, opt)		EXT4_SB(sb)->s_mount_opt2 &= \
+						~EXT4_MOUNT2_##opt
+#define set_opt2(sb, opt)		EXT4_SB(sb)->s_mount_opt2 |= \
+						EXT4_MOUNT2_##opt
+#define test_opt2(sb, opt)		(EXT4_SB(sb)->s_mount_opt2 & \
+					 EXT4_MOUNT2_##opt)
+
+#define ext4_test_and_set_bit		__test_and_set_bit_le
+#define ext4_set_bit			__set_bit_le
+#define ext4_set_bit_atomic		ext2_set_bit_atomic
+#define ext4_test_and_clear_bit		__test_and_clear_bit_le
+#define ext4_clear_bit			__clear_bit_le
+#define ext4_clear_bit_atomic		ext2_clear_bit_atomic
+#define ext4_test_bit			test_bit_le
+#define ext4_find_next_zero_bit		find_next_zero_bit_le
+#define ext4_find_next_bit		find_next_bit_le
+
+extern void ext4_set_bits(void *bm, int cur, int len);
+
+/*
+ * Maximal mount counts between two filesystem checks
+ */
+#define EXT4_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
+#define EXT4_DFL_CHECKINTERVAL		0	/* Don't use interval check */
+
+/*
+ * Behaviour when detecting errors
+ */
+#define EXT4_ERRORS_CONTINUE		1	/* Continue execution */
+#define EXT4_ERRORS_RO			2	/* Remount fs read-only */
+#define EXT4_ERRORS_PANIC		3	/* Panic */
+#define EXT4_ERRORS_DEFAULT		EXT4_ERRORS_CONTINUE
+
+/* Metadata checksum algorithm codes */
+#define EXT4_CRC32C_CHKSUM		1
+
+/*
+ * Structure of the super block
+ */
+struct ext4_super_block {
+/*00*/	__le32	s_inodes_count;		/* Inodes count */
+	__le32	s_blocks_count_lo;	/* Blocks count */
+	__le32	s_r_blocks_count_lo;	/* Reserved blocks count */
+	__le32	s_free_blocks_count_lo;	/* Free blocks count */
+/*10*/	__le32	s_free_inodes_count;	/* Free inodes count */
+	__le32	s_first_data_block;	/* First Data Block */
+	__le32	s_log_block_size;	/* Block size */
+	__le32	s_log_cluster_size;	/* Allocation cluster size */
+/*20*/	__le32	s_blocks_per_group;	/* # Blocks per group */
+	__le32	s_clusters_per_group;	/* # Clusters per group */
+	__le32	s_inodes_per_group;	/* # Inodes per group */
+	__le32	s_mtime;		/* Mount time */
+/*30*/	__le32	s_wtime;		/* Write time */
+	__le16	s_mnt_count;		/* Mount count */
+	__le16	s_max_mnt_count;	/* Maximal mount count */
+	__le16	s_magic;		/* Magic signature */
+	__le16	s_state;		/* File system state */
+	__le16	s_errors;		/* Behaviour when detecting errors */
+	__le16	s_minor_rev_level;	/* minor revision level */
+/*40*/	__le32	s_lastcheck;		/* time of last check */
+	__le32	s_checkinterval;	/* max. time between checks */
+	__le32	s_creator_os;		/* OS */
+	__le32	s_rev_level;		/* Revision level */
+/*50*/	__le16	s_def_resuid;		/* Default uid for reserved blocks */
+	__le16	s_def_resgid;		/* Default gid for reserved blocks */
+	/*
+	 * These fields are for EXT4_DYNAMIC_REV superblocks only.
+	 *
+	 * Note: the difference between the compatible feature set and
+	 * the incompatible feature set is that if there is a bit set
+	 * in the incompatible feature set that the kernel doesn't
+	 * know about, it should refuse to mount the filesystem.
+	 *
+	 * e2fsck's requirements are more strict; if it doesn't know
+	 * about a feature in either the compatible or incompatible
+	 * feature set, it must abort and not try to meddle with
+	 * things it doesn't understand...
+	 */
+	__le32	s_first_ino;		/* First non-reserved inode */
+	__le16  s_inode_size;		/* size of inode structure */
+	__le16	s_block_group_nr;	/* block group # of this superblock */
+	__le32	s_feature_compat;	/* compatible feature set */
+/*60*/	__le32	s_feature_incompat;	/* incompatible feature set */
+	__le32	s_feature_ro_compat;	/* readonly-compatible feature set */
+/*68*/	__u8	s_uuid[16];		/* 128-bit uuid for volume */
+/*78*/	char	s_volume_name[16];	/* volume name */
+/*88*/	char	s_last_mounted[64] __nonstring;	/* directory where last mounted */
+/*C8*/	__le32	s_algorithm_usage_bitmap; /* For compression */
+	/*
+	 * Performance hints.  Directory preallocation should only
+	 * happen if the EXT4_FEATURE_COMPAT_DIR_PREALLOC flag is on.
+	 */
+	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
+	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
+	__le16	s_reserved_gdt_blocks;	/* Per group desc for online growth */
+	/*
+	 * Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.
+	 */
+/*D0*/	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
+/*E0*/	__le32	s_journal_inum;		/* inode number of journal file */
+	__le32	s_journal_dev;		/* device number of journal file */
+	__le32	s_last_orphan;		/* start of list of inodes to delete */
+	__le32	s_hash_seed[4];		/* HTREE hash seed */
+	__u8	s_def_hash_version;	/* Default hash version to use */
+	__u8	s_jnl_backup_type;
+	__le16  s_desc_size;		/* size of group descriptor */
+/*100*/	__le32	s_default_mount_opts;
+	__le32	s_first_meta_bg;	/* First metablock block group */
+	__le32	s_mkfs_time;		/* When the filesystem was created */
+	__le32	s_jnl_blocks[17];	/* Backup of the journal inode */
+	/* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
+/*150*/	__le32	s_blocks_count_hi;	/* Blocks count */
+	__le32	s_r_blocks_count_hi;	/* Reserved blocks count */
+	__le32	s_free_blocks_count_hi;	/* Free blocks count */
+	__le16	s_min_extra_isize;	/* All inodes have at least # bytes */
+	__le16	s_want_extra_isize; 	/* New inodes should reserve # bytes */
+	__le32	s_flags;		/* Miscellaneous flags */
+	__le16  s_raid_stride;		/* RAID stride */
+	__le16  s_mmp_update_interval;  /* # seconds to wait in MMP checking */
+	__le64  s_mmp_block;            /* Block for multi-mount protection */
+	__le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
+	__u8	s_log_groups_per_flex;  /* FLEX_BG group size */
+	__u8	s_checksum_type;	/* metadata checksum algorithm used */
+	__u8	s_encryption_level;	/* versioning level for encryption */
+	__u8	s_reserved_pad;		/* Padding to next 32bits */
+	__le64	s_kbytes_written;	/* nr of lifetime kilobytes written */
+	__le32	s_snapshot_inum;	/* Inode number of active snapshot */
+	__le32	s_snapshot_id;		/* sequential ID of active snapshot */
+	__le64	s_snapshot_r_blocks_count; /* reserved blocks for active
+					      snapshot's future use */
+	__le32	s_snapshot_list;	/* inode number of the head of the
+					   on-disk snapshot list */
+#define EXT4_S_ERR_START offsetof(struct ext4_super_block, s_error_count)
+	__le32	s_error_count;		/* number of fs errors */
+	__le32	s_first_error_time;	/* first time an error happened */
+	__le32	s_first_error_ino;	/* inode involved in first error */
+	__le64	s_first_error_block;	/* block involved of first error */
+	__u8	s_first_error_func[32] __nonstring;	/* function where the error happened */
+	__le32	s_first_error_line;	/* line number where error happened */
+	__le32	s_last_error_time;	/* most recent time of an error */
+	__le32	s_last_error_ino;	/* inode involved in last error */
+	__le32	s_last_error_line;	/* line number where error happened */
+	__le64	s_last_error_block;	/* block involved of last error */
+	__u8	s_last_error_func[32] __nonstring;	/* function where the error happened */
+#define EXT4_S_ERR_END offsetof(struct ext4_super_block, s_mount_opts)
+	__u8	s_mount_opts[64];
+	__le32	s_usr_quota_inum;	/* inode for tracking user quota */
+	__le32	s_grp_quota_inum;	/* inode for tracking group quota */
+	__le32	s_overhead_clusters;	/* overhead blocks/clusters in fs */
+	__le32	s_backup_bgs[2];	/* groups with sparse_super2 SBs */
+	__u8	s_encrypt_algos[4];	/* Encryption algorithms in use  */
+	__u8	s_encrypt_pw_salt[16];	/* Salt used for string2key algorithm */
+	__le32	s_lpf_ino;		/* Location of the lost+found inode */
+	__le32	s_prj_quota_inum;	/* inode for tracking project quota */
+	__le32	s_checksum_seed;	/* crc32c(uuid) if csum_seed set */
+	__u8	s_wtime_hi;
+	__u8	s_mtime_hi;
+	__u8	s_mkfs_time_hi;
+	__u8	s_lastcheck_hi;
+	__u8	s_first_error_time_hi;
+	__u8	s_last_error_time_hi;
+	__u8	s_first_error_errcode;
+	__u8    s_last_error_errcode;
+	__le16  s_encoding;		/* Filename charset encoding */
+	__le16  s_encoding_flags;	/* Filename charset encoding flags */
+	__le32	s_reserved[95];		/* Padding to the end of the block */
+	__le32	s_checksum;		/* crc32c(superblock) */
+};
+
+#define EXT4_S_ERR_LEN (EXT4_S_ERR_END - EXT4_S_ERR_START)
+
+#ifdef __KERNEL__
+
+/* Number of quota types we support */
+#define EXT4_MAXQUOTAS 3
+
+#define EXT4_ENC_UTF8_12_1	1
+
+/*
+ * fourth extended-fs super-block data in memory
+ */
+struct ext4_sb_info {
+	unsigned long s_desc_size;	/* Size of a group descriptor in bytes */
+	unsigned long s_inodes_per_block;/* Number of inodes per block */
+	unsigned long s_blocks_per_group;/* Number of blocks in a group */
+	unsigned long s_clusters_per_group; /* Number of clusters in a group */
+	unsigned long s_inodes_per_group;/* Number of inodes in a group */
+	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
+	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
+	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
+	ext4_group_t s_groups_count;	/* Number of groups in the fs */
+	ext4_group_t s_blockfile_groups;/* Groups acceptable for non-extent files */
+	unsigned long s_overhead;  /* # of fs overhead clusters */
+	unsigned int s_cluster_ratio;	/* Number of blocks per cluster */
+	unsigned int s_cluster_bits;	/* log2 of s_cluster_ratio */
+	loff_t s_bitmap_maxbytes;	/* max bytes for bitmap files */
+	struct buffer_head * s_sbh;	/* Buffer containing the super block */
+	struct ext4_super_block *s_es;	/* Pointer to the super block in the buffer */
+	struct buffer_head * __rcu *s_group_desc;
+	unsigned int s_mount_opt;
+	unsigned int s_mount_opt2;
+	unsigned long s_mount_flags;
+	unsigned int s_def_mount_opt;
+	ext4_fsblk_t s_sb_block;
+	atomic64_t s_resv_clusters;
+	kuid_t s_resuid;
+	kgid_t s_resgid;
+	unsigned short s_mount_state;
+	unsigned short s_pad;
+	int s_addr_per_block_bits;
+	int s_desc_per_block_bits;
+	int s_inode_size;
+	int s_first_ino;
+	unsigned int s_inode_readahead_blks;
+	unsigned int s_inode_goal;
+	u32 s_hash_seed[4];
+	int s_def_hash_version;
+	int s_hash_unsigned;	/* 3 if hash should be signed, 0 if not */
+	struct percpu_counter s_freeclusters_counter;
+	struct percpu_counter s_freeinodes_counter;
+	struct percpu_counter s_dirs_counter;
+	struct percpu_counter s_dirtyclusters_counter;
+	struct percpu_counter s_sra_exceeded_retry_limit;
+	struct blockgroup_lock *s_blockgroup_lock;
+	struct proc_dir_entry *s_proc;
+	struct kobject s_kobj;
+	struct completion s_kobj_unregister;
+	struct super_block *s_sb;
+	struct buffer_head *s_mmp_bh;
+
+	/* Journaling */
+	struct journal_s *s_journal;
+	struct list_head s_orphan;
+	struct mutex s_orphan_lock;
+	unsigned long s_ext4_flags;		/* Ext4 superblock flags */
+	unsigned long s_commit_interval;
+	u32 s_max_batch_time;
+	u32 s_min_batch_time;
+	struct block_device *s_journal_bdev;
+#ifdef CONFIG_QUOTA
+	/* Names of quota files with journalled quota */
+	char __rcu *s_qf_names[EXT4_MAXQUOTAS];
+	int s_jquota_fmt;			/* Format of quota to use */
+#endif
+	unsigned int s_want_extra_isize; /* New inodes should reserve # bytes */
+	struct ext4_system_blocks __rcu *s_system_blks;
+
+#ifdef EXTENTS_STATS
+	/* ext4 extents stats */
+	unsigned long s_ext_min;
+	unsigned long s_ext_max;
+	unsigned long s_depth_max;
+	spinlock_t s_ext_stats_lock;
+	unsigned long s_ext_blocks;
+	unsigned long s_ext_extents;
+#endif
+
+	/* for buddy allocator */
+	struct ext4_group_info ** __rcu *s_group_info;
+	struct inode *s_buddy_cache;
+	spinlock_t s_md_lock;
+	unsigned short *s_mb_offsets;
+	unsigned int *s_mb_maxs;
+	unsigned int s_group_info_size;
+	unsigned int s_mb_free_pending;
+	struct list_head s_freed_data_list;	/* List of blocks to be freed
+						   after commit completed */
+
+	/* tunables */
+	unsigned long s_stripe;
+	unsigned int s_mb_stream_request;
+	unsigned int s_mb_max_to_scan;
+	unsigned int s_mb_min_to_scan;
+	unsigned int s_mb_stats;
+	unsigned int s_mb_order2_reqs;
+	unsigned int s_mb_group_prealloc;
+	unsigned int s_mb_max_inode_prealloc;
+	unsigned int s_max_dir_size_kb;
+	/* where last allocation was done - for stream allocation */
+	unsigned long s_mb_last_group;
+	unsigned long s_mb_last_start;
+	unsigned int s_mb_prefetch;
+	unsigned int s_mb_prefetch_limit;
+
+	/* stats for buddy allocator */
+	atomic_t s_bal_reqs;	/* number of reqs with len > 1 */
+	atomic_t s_bal_success;	/* we found long enough chunks */
+	atomic_t s_bal_allocated;	/* in blocks */
+	atomic_t s_bal_ex_scanned;	/* total extents scanned */
+	atomic_t s_bal_groups_scanned;	/* number of groups scanned */
+	atomic_t s_bal_goals;	/* goal hits */
+	atomic_t s_bal_breaks;	/* too long searches */
+	atomic_t s_bal_2orders;	/* 2^order hits */
+	atomic64_t s_bal_cX_groups_considered[4];
+	atomic64_t s_bal_cX_hits[4];
+	atomic64_t s_bal_cX_failed[4];		/* cX loop didn't find blocks */
+	atomic_t s_mb_buddies_generated;	/* number of buddies generated */
+	atomic64_t s_mb_generation_time;
+	atomic_t s_mb_lost_chunks;
+	atomic_t s_mb_preallocated;
+	atomic_t s_mb_discarded;
+	atomic_t s_lock_busy;
+
+	/* locality groups */
+	struct ext4_locality_group __percpu *s_locality_groups;
+
+	/* for write statistics */
+	unsigned long s_sectors_written_start;
+	u64 s_kbytes_written;
+
+	/* the size of zero-out chunk */
+	unsigned int s_extent_max_zeroout_kb;
+
+	unsigned int s_log_groups_per_flex;
+	struct flex_groups * __rcu *s_flex_groups;
+	ext4_group_t s_flex_groups_allocated;
+
+	/* workqueue for reserved extent conversions (buffered io) */
+	struct workqueue_struct *rsv_conversion_wq;
+
+	/* timer for periodic error stats printing */
+	struct timer_list s_err_report;
+
+	/* Lazy inode table initialization info */
+	struct ext4_li_request *s_li_request;
+	/* Wait multiplier for lazy initialization thread */
+	unsigned int s_li_wait_mult;
+
+	/* Kernel thread for multiple mount protection */
+	struct task_struct *s_mmp_tsk;
+
+	/* record the last minlen when FITRIM is called. */
+	unsigned long s_last_trim_minblks;
+
+	/* Reference to checksum algorithm driver via cryptoapi */
+	struct crypto_shash *s_chksum_driver;
+
+	/* Precomputed FS UUID checksum for seeding other checksums */
+	__u32 s_csum_seed;
+
+	/* Reclaim extents from extent status tree */
+	struct shrinker s_es_shrinker;
+	struct list_head s_es_list;	/* List of inodes with reclaimable extents */
+	long s_es_nr_inode;
+	struct ext4_es_stats s_es_stats;
+	struct mb_cache *s_ea_block_cache;
+	struct mb_cache *s_ea_inode_cache;
+	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
+
+	/* Ratelimit ext4 messages. */
+	struct ratelimit_state s_err_ratelimit_state;
+	struct ratelimit_state s_warning_ratelimit_state;
+	struct ratelimit_state s_msg_ratelimit_state;
+	atomic_t s_warning_count;
+	atomic_t s_msg_count;
+
+	/* Encryption policy for '-o test_dummy_encryption' */
+	struct fscrypt_dummy_policy s_dummy_enc_policy;
+
+	/*
+	 * Barrier between writepages ops and changing any inode's JOURNAL_DATA
+	 * or EXTENTS flag.
+	 */
+	struct percpu_rw_semaphore s_writepages_rwsem;
+	struct dax_device *s_daxdev;
+#ifdef CONFIG_EXT4_DEBUG
+	unsigned long s_simulate_fail;
+#endif
+	/* Record the errseq of the backing block device */
+	errseq_t s_bdev_wb_err;
+	spinlock_t s_bdev_wb_lock;
+
+	/* Ext4 fast commit stuff */
+	atomic_t s_fc_subtid;
+	atomic_t s_fc_ineligible_updates;
+	/*
+	 * After commit starts, the main queue gets locked, and the further
+	 * updates get added in the staging queue.
+	 */
+#define FC_Q_MAIN	0
+#define FC_Q_STAGING	1
+	struct list_head s_fc_q[2];	/* Inodes staged for fast commit
+					 * that have data changes in them.
+					 */
+	struct list_head s_fc_dentry_q[2];	/* directory entry updates */
+	unsigned int s_fc_bytes;
+	/*
+	 * Main fast commit lock. This lock protects accesses to the
+	 * following fields:
+	 * ei->i_fc_list, s_fc_dentry_q, s_fc_q, s_fc_bytes, s_fc_bh.
+	 */
+	spinlock_t s_fc_lock;
+	struct buffer_head *s_fc_bh;
+	struct ext4_fc_stats s_fc_stats;
+	u64 s_fc_avg_commit_time;
+#ifdef CONFIG_EXT4_DEBUG
+	int s_fc_debug_max_replay;
+#endif
+	struct ext4_fc_replay_state s_fc_replay_state;
+};
+
+static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+static inline struct ext4_inode_info *EXT4_I(struct inode *inode)
+{
+	return container_of(inode, struct ext4_inode_info, vfs_inode);
+}
+
+static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
+{
+	return ino == EXT4_ROOT_INO ||
+		(ino >= EXT4_FIRST_INO(sb) &&
+		 ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
+}
+
+/*
+ * Returns: sbi->field[index]
+ * Used to access an array element from the following sbi fields which require
+ * rcu protection to avoid dereferencing an invalid pointer due to reassignment
+ * - s_group_desc
+ * - s_group_info
+ * - s_flex_group
+ */
+#define sbi_array_rcu_deref(sbi, field, index)				   \
+({									   \
+	typeof(*((sbi)->field)) _v;					   \
+	rcu_read_lock();						   \
+	_v = ((typeof(_v)*)rcu_dereference((sbi)->field))[index];	   \
+	rcu_read_unlock();						   \
+	_v;								   \
+})
+
+/*
+ * run-time mount flags
+ */
+enum {
+	EXT4_MF_MNTDIR_SAMPLED,
+	EXT4_MF_FS_ABORTED,	/* Fatal error detected */
+	EXT4_MF_FC_INELIGIBLE,	/* Fast commit ineligible */
+	EXT4_MF_FC_COMMITTING	/* File system underoing a fast
+				 * commit.
+				 */
+};
+
+static inline void ext4_set_mount_flag(struct super_block *sb, int bit)
+{
+	set_bit(bit, &EXT4_SB(sb)->s_mount_flags);
+}
+
+static inline void ext4_clear_mount_flag(struct super_block *sb, int bit)
+{
+	clear_bit(bit, &EXT4_SB(sb)->s_mount_flags);
+}
+
+static inline int ext4_test_mount_flag(struct super_block *sb, int bit)
+{
+	return test_bit(bit, &EXT4_SB(sb)->s_mount_flags);
+}
+
+
+/*
+ * Simulate_fail codes
+ */
+#define EXT4_SIM_BBITMAP_EIO	1
+#define EXT4_SIM_BBITMAP_CRC	2
+#define EXT4_SIM_IBITMAP_EIO	3
+#define EXT4_SIM_IBITMAP_CRC	4
+#define EXT4_SIM_INODE_EIO	5
+#define EXT4_SIM_INODE_CRC	6
+#define EXT4_SIM_DIRBLOCK_EIO	7
+#define EXT4_SIM_DIRBLOCK_CRC	8
+
+static inline bool ext4_simulate_fail(struct super_block *sb,
+				     unsigned long code)
+{
+#ifdef CONFIG_EXT4_DEBUG
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (unlikely(sbi->s_simulate_fail == code)) {
+		sbi->s_simulate_fail = 0;
+		return true;
+	}
+#endif
+	return false;
+}
+
+static inline void ext4_simulate_fail_bh(struct super_block *sb,
+					 struct buffer_head *bh,
+					 unsigned long code)
+{
+	if (!IS_ERR(bh) && ext4_simulate_fail(sb, code))
+		clear_buffer_uptodate(bh);
+}
+
+/*
+ * Error number codes for s_{first,last}_error_errno
+ *
+ * Linux errno numbers are architecture specific, so we need to translate
+ * them into something which is architecture independent.   We don't define
+ * codes for all errno's; just the ones which are most likely to be the cause
+ * of an ext4_error() call.
+ */
+#define EXT4_ERR_UNKNOWN	 1
+#define EXT4_ERR_EIO		 2
+#define EXT4_ERR_ENOMEM		 3
+#define EXT4_ERR_EFSBADCRC	 4
+#define EXT4_ERR_EFSCORRUPTED	 5
+#define EXT4_ERR_ENOSPC		 6
+#define EXT4_ERR_ENOKEY		 7
+#define EXT4_ERR_EROFS		 8
+#define EXT4_ERR_EFBIG		 9
+#define EXT4_ERR_EEXIST		10
+#define EXT4_ERR_ERANGE		11
+#define EXT4_ERR_EOVERFLOW	12
+#define EXT4_ERR_EBUSY		13
+#define EXT4_ERR_ENOTDIR	14
+#define EXT4_ERR_ENOTEMPTY	15
+#define EXT4_ERR_ESHUTDOWN	16
+#define EXT4_ERR_EFAULT		17
+
+/*
+ * Inode dynamic state flags
+ */
+enum {
+	EXT4_STATE_JDATA,		/* journaled data exists */
+	EXT4_STATE_NEW,			/* inode is newly created */
+	EXT4_STATE_XATTR,		/* has in-inode xattrs */
+	EXT4_STATE_NO_EXPAND,		/* No space for expansion */
+	EXT4_STATE_DA_ALLOC_CLOSE,	/* Alloc DA blks on close */
+	EXT4_STATE_EXT_MIGRATE,		/* Inode is migrating */
+	EXT4_STATE_NEWENTRY,		/* File just added to dir */
+	EXT4_STATE_MAY_INLINE_DATA,	/* may have in-inode data */
+	EXT4_STATE_EXT_PRECACHED,	/* extents have been precached */
+	EXT4_STATE_LUSTRE_EA_INODE,	/* Lustre-style ea_inode */
+	EXT4_STATE_VERITY_IN_PROGRESS,	/* building fs-verity Merkle tree */
+	EXT4_STATE_FC_COMMITTING,	/* Fast commit ongoing */
+};
+
+#define EXT4_INODE_BIT_FNS(name, field, offset)				\
+static inline int ext4_test_inode_##name(struct inode *inode, int bit)	\
+{									\
+	return test_bit(bit + (offset), &EXT4_I(inode)->i_##field);	\
+}									\
+static inline void ext4_set_inode_##name(struct inode *inode, int bit)	\
+{									\
+	set_bit(bit + (offset), &EXT4_I(inode)->i_##field);		\
+}									\
+static inline void ext4_clear_inode_##name(struct inode *inode, int bit) \
+{									\
+	clear_bit(bit + (offset), &EXT4_I(inode)->i_##field);		\
+}
+
+/* Add these declarations here only so that these functions can be
+ * found by name.  Otherwise, they are very hard to locate. */
+static inline int ext4_test_inode_flag(struct inode *inode, int bit);
+static inline void ext4_set_inode_flag(struct inode *inode, int bit);
+static inline void ext4_clear_inode_flag(struct inode *inode, int bit);
+EXT4_INODE_BIT_FNS(flag, flags, 0)
+
+/* Add these declarations here only so that these functions can be
+ * found by name.  Otherwise, they are very hard to locate. */
+static inline int ext4_test_inode_state(struct inode *inode, int bit);
+static inline void ext4_set_inode_state(struct inode *inode, int bit);
+static inline void ext4_clear_inode_state(struct inode *inode, int bit);
+#if (BITS_PER_LONG < 64)
+EXT4_INODE_BIT_FNS(state, state_flags, 0)
+
+static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
+{
+	(ei)->i_state_flags = 0;
+}
+#else
+EXT4_INODE_BIT_FNS(state, flags, 32)
+
+static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
+{
+	/* We depend on the fact that callers will set i_flags */
+}
+#endif
+#else
+/* Assume that user mode programs are passing in an ext4fs superblock, not
+ * a kernel struct super_block.  This will allow us to call the feature-test
+ * macros from user land. */
+#define EXT4_SB(sb)	(sb)
+#endif
+
+static inline bool ext4_verity_in_progress(struct inode *inode)
+{
+	return IS_ENABLED(CONFIG_FS_VERITY) &&
+	       ext4_test_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS);
+}
+
+#define NEXT_ORPHAN(inode) EXT4_I(inode)->i_dtime
+
+/*
+ * Codes for operating systems
+ */
+#define EXT4_OS_LINUX		0
+#define EXT4_OS_HURD		1
+#define EXT4_OS_MASIX		2
+#define EXT4_OS_FREEBSD		3
+#define EXT4_OS_LITES		4
+
+/*
+ * Revision levels
+ */
+#define EXT4_GOOD_OLD_REV	0	/* The good old (original) format */
+#define EXT4_DYNAMIC_REV	1	/* V2 format w/ dynamic inode sizes */
+
+#define EXT4_CURRENT_REV	EXT4_GOOD_OLD_REV
+#define EXT4_MAX_SUPP_REV	EXT4_DYNAMIC_REV
+
+#define EXT4_GOOD_OLD_INODE_SIZE 128
+
+#define EXT4_EXTRA_TIMESTAMP_MAX	(((s64)1 << 34) - 1  + S32_MIN)
+#define EXT4_NON_EXTRA_TIMESTAMP_MAX	S32_MAX
+#define EXT4_TIMESTAMP_MIN		S32_MIN
+
+/*
+ * Feature set definitions
+ */
+
+#define EXT4_FEATURE_COMPAT_DIR_PREALLOC	0x0001
+#define EXT4_FEATURE_COMPAT_IMAGIC_INODES	0x0002
+#define EXT4_FEATURE_COMPAT_HAS_JOURNAL		0x0004
+#define EXT4_FEATURE_COMPAT_EXT_ATTR		0x0008
+#define EXT4_FEATURE_COMPAT_RESIZE_INODE	0x0010
+#define EXT4_FEATURE_COMPAT_DIR_INDEX		0x0020
+#define EXT4_FEATURE_COMPAT_SPARSE_SUPER2	0x0200
+/*
+ * The reason why "FAST_COMMIT" is a compat feature is that, FS becomes
+ * incompatible only if fast commit blocks are present in the FS. Since we
+ * clear the journal (and thus the fast commit blocks), we don't mark FS as
+ * incompatible. We also have a JBD2 incompat feature, which gets set when
+ * there are fast commit blocks present in the journal.
+ */
+#define EXT4_FEATURE_COMPAT_FAST_COMMIT		0x0400
+#define EXT4_FEATURE_COMPAT_STABLE_INODES	0x0800
+
+#define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
+#define EXT4_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
+#define EXT4_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
+#define EXT4_FEATURE_RO_COMPAT_HUGE_FILE        0x0008
+#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010
+#define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020
+#define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040
+#define EXT4_FEATURE_RO_COMPAT_QUOTA		0x0100
+#define EXT4_FEATURE_RO_COMPAT_BIGALLOC		0x0200
+/*
+ * METADATA_CSUM also enables group descriptor checksums (GDT_CSUM).  When
+ * METADATA_CSUM is set, group descriptor checksums use the same algorithm as
+ * all other data structures' checksums.  However, the METADATA_CSUM and
+ * GDT_CSUM bits are mutually exclusive.
+ */
+#define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM	0x0400
+#define EXT4_FEATURE_RO_COMPAT_READONLY		0x1000
+#define EXT4_FEATURE_RO_COMPAT_PROJECT		0x2000
+#define EXT4_FEATURE_RO_COMPAT_VERITY		0x8000
+
+#define EXT4_FEATURE_INCOMPAT_COMPRESSION	0x0001
+#define EXT4_FEATURE_INCOMPAT_FILETYPE		0x0002
+#define EXT4_FEATURE_INCOMPAT_RECOVER		0x0004 /* Needs recovery */
+#define EXT4_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008 /* Journal device */
+#define EXT4_FEATURE_INCOMPAT_META_BG		0x0010
+#define EXT4_FEATURE_INCOMPAT_EXTENTS		0x0040 /* extents support */
+#define EXT4_FEATURE_INCOMPAT_64BIT		0x0080
+#define EXT4_FEATURE_INCOMPAT_MMP               0x0100
+#define EXT4_FEATURE_INCOMPAT_FLEX_BG		0x0200
+#define EXT4_FEATURE_INCOMPAT_EA_INODE		0x0400 /* EA in inode */
+#define EXT4_FEATURE_INCOMPAT_DIRDATA		0x1000 /* data in dirent */
+#define EXT4_FEATURE_INCOMPAT_CSUM_SEED		0x2000
+#define EXT4_FEATURE_INCOMPAT_LARGEDIR		0x4000 /* >2GB or 3-lvl htree */
+#define EXT4_FEATURE_INCOMPAT_INLINE_DATA	0x8000 /* data in inode */
+#define EXT4_FEATURE_INCOMPAT_ENCRYPT		0x10000
+#define EXT4_FEATURE_INCOMPAT_CASEFOLD		0x20000
+
+extern void ext4_update_dynamic_rev(struct super_block *sb);
+
+#define EXT4_FEATURE_COMPAT_FUNCS(name, flagname) \
+static inline bool ext4_has_feature_##name(struct super_block *sb) \
+{ \
+	return ((EXT4_SB(sb)->s_es->s_feature_compat & \
+		cpu_to_le32(EXT4_FEATURE_COMPAT_##flagname)) != 0); \
+} \
+static inline void ext4_set_feature_##name(struct super_block *sb) \
+{ \
+	ext4_update_dynamic_rev(sb); \
+	EXT4_SB(sb)->s_es->s_feature_compat |= \
+		cpu_to_le32(EXT4_FEATURE_COMPAT_##flagname); \
+} \
+static inline void ext4_clear_feature_##name(struct super_block *sb) \
+{ \
+	EXT4_SB(sb)->s_es->s_feature_compat &= \
+		~cpu_to_le32(EXT4_FEATURE_COMPAT_##flagname); \
+}
+
+#define EXT4_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
+static inline bool ext4_has_feature_##name(struct super_block *sb) \
+{ \
+	return ((EXT4_SB(sb)->s_es->s_feature_ro_compat & \
+		cpu_to_le32(EXT4_FEATURE_RO_COMPAT_##flagname)) != 0); \
+} \
+static inline void ext4_set_feature_##name(struct super_block *sb) \
+{ \
+	ext4_update_dynamic_rev(sb); \
+	EXT4_SB(sb)->s_es->s_feature_ro_compat |= \
+		cpu_to_le32(EXT4_FEATURE_RO_COMPAT_##flagname); \
+} \
+static inline void ext4_clear_feature_##name(struct super_block *sb) \
+{ \
+	EXT4_SB(sb)->s_es->s_feature_ro_compat &= \
+		~cpu_to_le32(EXT4_FEATURE_RO_COMPAT_##flagname); \
+}
+
+#define EXT4_FEATURE_INCOMPAT_FUNCS(name, flagname) \
+static inline bool ext4_has_feature_##name(struct super_block *sb) \
+{ \
+	return ((EXT4_SB(sb)->s_es->s_feature_incompat & \
+		cpu_to_le32(EXT4_FEATURE_INCOMPAT_##flagname)) != 0); \
+} \
+static inline void ext4_set_feature_##name(struct super_block *sb) \
+{ \
+	ext4_update_dynamic_rev(sb); \
+	EXT4_SB(sb)->s_es->s_feature_incompat |= \
+		cpu_to_le32(EXT4_FEATURE_INCOMPAT_##flagname); \
+} \
+static inline void ext4_clear_feature_##name(struct super_block *sb) \
+{ \
+	EXT4_SB(sb)->s_es->s_feature_incompat &= \
+		~cpu_to_le32(EXT4_FEATURE_INCOMPAT_##flagname); \
+}
+
+EXT4_FEATURE_COMPAT_FUNCS(dir_prealloc,		DIR_PREALLOC)
+EXT4_FEATURE_COMPAT_FUNCS(imagic_inodes,	IMAGIC_INODES)
+EXT4_FEATURE_COMPAT_FUNCS(journal,		HAS_JOURNAL)
+EXT4_FEATURE_COMPAT_FUNCS(xattr,		EXT_ATTR)
+EXT4_FEATURE_COMPAT_FUNCS(resize_inode,		RESIZE_INODE)
+EXT4_FEATURE_COMPAT_FUNCS(dir_index,		DIR_INDEX)
+EXT4_FEATURE_COMPAT_FUNCS(sparse_super2,	SPARSE_SUPER2)
+EXT4_FEATURE_COMPAT_FUNCS(fast_commit,		FAST_COMMIT)
+EXT4_FEATURE_COMPAT_FUNCS(stable_inodes,	STABLE_INODES)
+
+EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super,	SPARSE_SUPER)
+EXT4_FEATURE_RO_COMPAT_FUNCS(large_file,	LARGE_FILE)
+EXT4_FEATURE_RO_COMPAT_FUNCS(btree_dir,		BTREE_DIR)
+EXT4_FEATURE_RO_COMPAT_FUNCS(huge_file,		HUGE_FILE)
+EXT4_FEATURE_RO_COMPAT_FUNCS(gdt_csum,		GDT_CSUM)
+EXT4_FEATURE_RO_COMPAT_FUNCS(dir_nlink,		DIR_NLINK)
+EXT4_FEATURE_RO_COMPAT_FUNCS(extra_isize,	EXTRA_ISIZE)
+EXT4_FEATURE_RO_COMPAT_FUNCS(quota,		QUOTA)
+EXT4_FEATURE_RO_COMPAT_FUNCS(bigalloc,		BIGALLOC)
+EXT4_FEATURE_RO_COMPAT_FUNCS(metadata_csum,	METADATA_CSUM)
+EXT4_FEATURE_RO_COMPAT_FUNCS(readonly,		READONLY)
+EXT4_FEATURE_RO_COMPAT_FUNCS(project,		PROJECT)
+EXT4_FEATURE_RO_COMPAT_FUNCS(verity,		VERITY)
+
+EXT4_FEATURE_INCOMPAT_FUNCS(compression,	COMPRESSION)
+EXT4_FEATURE_INCOMPAT_FUNCS(filetype,		FILETYPE)
+EXT4_FEATURE_INCOMPAT_FUNCS(journal_needs_recovery,	RECOVER)
+EXT4_FEATURE_INCOMPAT_FUNCS(journal_dev,	JOURNAL_DEV)
+EXT4_FEATURE_INCOMPAT_FUNCS(meta_bg,		META_BG)
+EXT4_FEATURE_INCOMPAT_FUNCS(extents,		EXTENTS)
+EXT4_FEATURE_INCOMPAT_FUNCS(64bit,		64BIT)
+EXT4_FEATURE_INCOMPAT_FUNCS(mmp,		MMP)
+EXT4_FEATURE_INCOMPAT_FUNCS(flex_bg,		FLEX_BG)
+EXT4_FEATURE_INCOMPAT_FUNCS(ea_inode,		EA_INODE)
+EXT4_FEATURE_INCOMPAT_FUNCS(dirdata,		DIRDATA)
+EXT4_FEATURE_INCOMPAT_FUNCS(csum_seed,		CSUM_SEED)
+EXT4_FEATURE_INCOMPAT_FUNCS(largedir,		LARGEDIR)
+EXT4_FEATURE_INCOMPAT_FUNCS(inline_data,	INLINE_DATA)
+EXT4_FEATURE_INCOMPAT_FUNCS(encrypt,		ENCRYPT)
+EXT4_FEATURE_INCOMPAT_FUNCS(casefold,		CASEFOLD)
+
+#define EXT2_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
+#define EXT2_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \
+					 EXT4_FEATURE_INCOMPAT_META_BG)
+#define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
+					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR)
+
+#define EXT3_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
+#define EXT3_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \
+					 EXT4_FEATURE_INCOMPAT_RECOVER| \
+					 EXT4_FEATURE_INCOMPAT_META_BG)
+#define EXT3_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
+					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR)
+
+#define EXT4_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
+#define EXT4_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \
+					 EXT4_FEATURE_INCOMPAT_RECOVER| \
+					 EXT4_FEATURE_INCOMPAT_META_BG| \
+					 EXT4_FEATURE_INCOMPAT_EXTENTS| \
+					 EXT4_FEATURE_INCOMPAT_64BIT| \
+					 EXT4_FEATURE_INCOMPAT_FLEX_BG| \
+					 EXT4_FEATURE_INCOMPAT_EA_INODE| \
+					 EXT4_FEATURE_INCOMPAT_MMP | \
+					 EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
+					 EXT4_FEATURE_INCOMPAT_ENCRYPT | \
+					 EXT4_FEATURE_INCOMPAT_CASEFOLD | \
+					 EXT4_FEATURE_INCOMPAT_CSUM_SEED | \
+					 EXT4_FEATURE_INCOMPAT_LARGEDIR)
+#define EXT4_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
+					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
+					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \
+					 EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE | \
+					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR |\
+					 EXT4_FEATURE_RO_COMPAT_HUGE_FILE |\
+					 EXT4_FEATURE_RO_COMPAT_BIGALLOC |\
+					 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM|\
+					 EXT4_FEATURE_RO_COMPAT_QUOTA |\
+					 EXT4_FEATURE_RO_COMPAT_PROJECT |\
+					 EXT4_FEATURE_RO_COMPAT_VERITY)
+
+#define EXTN_FEATURE_FUNCS(ver) \
+static inline bool ext4_has_unknown_ext##ver##_compat_features(struct super_block *sb) \
+{ \
+	return ((EXT4_SB(sb)->s_es->s_feature_compat & \
+		cpu_to_le32(~EXT##ver##_FEATURE_COMPAT_SUPP)) != 0); \
+} \
+static inline bool ext4_has_unknown_ext##ver##_ro_compat_features(struct super_block *sb) \
+{ \
+	return ((EXT4_SB(sb)->s_es->s_feature_ro_compat & \
+		cpu_to_le32(~EXT##ver##_FEATURE_RO_COMPAT_SUPP)) != 0); \
+} \
+static inline bool ext4_has_unknown_ext##ver##_incompat_features(struct super_block *sb) \
+{ \
+	return ((EXT4_SB(sb)->s_es->s_feature_incompat & \
+		cpu_to_le32(~EXT##ver##_FEATURE_INCOMPAT_SUPP)) != 0); \
+}
+
+EXTN_FEATURE_FUNCS(2)
+EXTN_FEATURE_FUNCS(3)
+EXTN_FEATURE_FUNCS(4)
+
+static inline bool ext4_has_compat_features(struct super_block *sb)
+{
+	return (EXT4_SB(sb)->s_es->s_feature_compat != 0);
+}
+static inline bool ext4_has_ro_compat_features(struct super_block *sb)
+{
+	return (EXT4_SB(sb)->s_es->s_feature_ro_compat != 0);
+}
+static inline bool ext4_has_incompat_features(struct super_block *sb)
+{
+	return (EXT4_SB(sb)->s_es->s_feature_incompat != 0);
+}
+
+/*
+ * Superblock flags
+ */
+#define EXT4_FLAGS_RESIZING	0
+#define EXT4_FLAGS_SHUTDOWN	1
+#define EXT4_FLAGS_BDEV_IS_DAX	2
+
+static inline int ext4_forced_shutdown(struct ext4_sb_info *sbi)
+{
+	return test_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
+}
+
+
+/*
+ * Default values for user and/or group using reserved blocks
+ */
+#define	EXT4_DEF_RESUID		0
+#define	EXT4_DEF_RESGID		0
+
+/*
+ * Default project ID
+ */
+#define	EXT4_DEF_PROJID		0
+
+#define EXT4_DEF_INODE_READAHEAD_BLKS	32
+
+/*
+ * Default mount options
+ */
+#define EXT4_DEFM_DEBUG		0x0001
+#define EXT4_DEFM_BSDGROUPS	0x0002
+#define EXT4_DEFM_XATTR_USER	0x0004
+#define EXT4_DEFM_ACL		0x0008
+#define EXT4_DEFM_UID16		0x0010
+#define EXT4_DEFM_JMODE		0x0060
+#define EXT4_DEFM_JMODE_DATA	0x0020
+#define EXT4_DEFM_JMODE_ORDERED	0x0040
+#define EXT4_DEFM_JMODE_WBACK	0x0060
+#define EXT4_DEFM_NOBARRIER	0x0100
+#define EXT4_DEFM_BLOCK_VALIDITY 0x0200
+#define EXT4_DEFM_DISCARD	0x0400
+#define EXT4_DEFM_NODELALLOC	0x0800
+
+/*
+ * Default journal batch times
+ */
+#define EXT4_DEF_MIN_BATCH_TIME	0
+#define EXT4_DEF_MAX_BATCH_TIME	15000 /* 15ms */
+
+/*
+ * Minimum number of groups in a flexgroup before we separate out
+ * directories into the first block group of a flexgroup
+ */
+#define EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME	4
+
+/*
+ * Structure of a directory entry
+ */
+#define EXT4_NAME_LEN 255
+/*
+ * Base length of the ext4 directory entry excluding the name length
+ */
+#define EXT4_BASE_DIR_LEN (sizeof(struct ext4_dir_entry_2) - EXT4_NAME_LEN)
+
+struct ext4_dir_entry {
+	__le32	inode;			/* Inode number */
+	__le16	rec_len;		/* Directory entry length */
+	__le16	name_len;		/* Name length */
+	char	name[EXT4_NAME_LEN];	/* File name */
+};
+
+/*
+ * The new version of the directory entry.  Since EXT4 structures are
+ * stored in intel byte order, and the name_len field could never be
+ * bigger than 255 chars, it's safe to reclaim the extra byte for the
+ * file_type field.
+ */
+struct ext4_dir_entry_2 {
+	__le32	inode;			/* Inode number */
+	__le16	rec_len;		/* Directory entry length */
+	__u8	name_len;		/* Name length */
+	__u8	file_type;		/* See file type macros EXT4_FT_* below */
+	char	name[EXT4_NAME_LEN];	/* File name */
+};
+
+/*
+ * This is a bogus directory entry at the end of each leaf block that
+ * records checksums.
+ */
+struct ext4_dir_entry_tail {
+	__le32	det_reserved_zero1;	/* Pretend to be unused */
+	__le16	det_rec_len;		/* 12 */
+	__u8	det_reserved_zero2;	/* Zero name length */
+	__u8	det_reserved_ft;	/* 0xDE, fake file type */
+	__le32	det_checksum;		/* crc32c(uuid+inum+dirblock) */
+};
+
+#define EXT4_DIRENT_TAIL(block, blocksize) \
+	((struct ext4_dir_entry_tail *)(((void *)(block)) + \
+					((blocksize) - \
+					 sizeof(struct ext4_dir_entry_tail))))
+
+/*
+ * Ext4 directory file types.  Only the low 3 bits are used.  The
+ * other bits are reserved for now.
+ */
+#define EXT4_FT_UNKNOWN		0
+#define EXT4_FT_REG_FILE	1
+#define EXT4_FT_DIR		2
+#define EXT4_FT_CHRDEV		3
+#define EXT4_FT_BLKDEV		4
+#define EXT4_FT_FIFO		5
+#define EXT4_FT_SOCK		6
+#define EXT4_FT_SYMLINK		7
+
+#define EXT4_FT_MAX		8
+
+#define EXT4_FT_DIR_CSUM	0xDE
+
+/*
+ * EXT4_DIR_PAD defines the directory entries boundaries
+ *
+ * NOTE: It must be a multiple of 4
+ */
+#define EXT4_DIR_PAD			4
+#define EXT4_DIR_ROUND			(EXT4_DIR_PAD - 1)
+#define EXT4_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT4_DIR_ROUND) & \
+					 ~EXT4_DIR_ROUND)
+#define EXT4_MAX_REC_LEN		((1<<16)-1)
+
+/*
+ * If we ever get support for fs block sizes > page_size, we'll need
+ * to remove the #if statements in the next two functions...
+ */
+static inline unsigned int
+ext4_rec_len_from_disk(__le16 dlen, unsigned blocksize)
+{
+	unsigned len = le16_to_cpu(dlen);
+
+#if (PAGE_SIZE >= 65536)
+	if (len == EXT4_MAX_REC_LEN || len == 0)
+		return blocksize;
+	return (len & 65532) | ((len & 3) << 16);
+#else
+	return len;
+#endif
+}
+
+static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize)
+{
+	if ((len > blocksize) || (blocksize > (1 << 18)) || (len & 3))
+		BUG();
+#if (PAGE_SIZE >= 65536)
+	if (len < 65536)
+		return cpu_to_le16(len);
+	if (len == blocksize) {
+		if (blocksize == 65536)
+			return cpu_to_le16(EXT4_MAX_REC_LEN);
+		else
+			return cpu_to_le16(0);
+	}
+	return cpu_to_le16((len & 65532) | ((len >> 16) & 3));
+#else
+	return cpu_to_le16(len);
+#endif
+}
+
+/*
+ * Hash Tree Directory indexing
+ * (c) Daniel Phillips, 2001
+ */
+
+#define is_dx(dir) (ext4_has_feature_dir_index((dir)->i_sb) && \
+		    ext4_test_inode_flag((dir), EXT4_INODE_INDEX))
+#define EXT4_DIR_LINK_MAX(dir) unlikely((dir)->i_nlink >= EXT4_LINK_MAX && \
+		    !(ext4_has_feature_dir_nlink((dir)->i_sb) && is_dx(dir)))
+#define EXT4_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1)
+
+/* Legal values for the dx_root hash_version field: */
+
+#define DX_HASH_LEGACY			0
+#define DX_HASH_HALF_MD4		1
+#define DX_HASH_TEA			2
+#define DX_HASH_LEGACY_UNSIGNED		3
+#define DX_HASH_HALF_MD4_UNSIGNED	4
+#define DX_HASH_TEA_UNSIGNED		5
+
+static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc,
+			      const void *address, unsigned int length)
+{
+	struct {
+		struct shash_desc shash;
+		char ctx[4];
+	} desc;
+
+	BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver)!=sizeof(desc.ctx));
+
+	desc.shash.tfm = sbi->s_chksum_driver;
+	*(u32 *)desc.ctx = crc;
+
+	BUG_ON(crypto_shash_update(&desc.shash, address, length));
+
+	return *(u32 *)desc.ctx;
+}
+
+#ifdef __KERNEL__
+
+/* hash info structure used by the directory hash */
+struct dx_hash_info
+{
+	u32		hash;
+	u32		minor_hash;
+	int		hash_version;
+	u32		*seed;
+};
+
+
+/* 32 and 64 bit signed EOF for dx directories */
+#define EXT4_HTREE_EOF_32BIT   ((1UL  << (32 - 1)) - 1)
+#define EXT4_HTREE_EOF_64BIT   ((1ULL << (64 - 1)) - 1)
+
+
+/*
+ * Control parameters used by ext4_htree_next_block
+ */
+#define HASH_NB_ALWAYS		1
+
+struct ext4_filename {
+	const struct qstr *usr_fname;
+	struct fscrypt_str disk_name;
+	struct dx_hash_info hinfo;
+#ifdef CONFIG_FS_ENCRYPTION
+	struct fscrypt_str crypto_buf;
+#endif
+#ifdef CONFIG_UNICODE
+	struct fscrypt_str cf_name;
+#endif
+};
+
+#define fname_name(p) ((p)->disk_name.name)
+#define fname_len(p)  ((p)->disk_name.len)
+
+/*
+ * Describe an inode's exact location on disk and in memory
+ */
+struct ext4_iloc
+{
+	struct buffer_head *bh;
+	unsigned long offset;
+	ext4_group_t block_group;
+};
+
+static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
+{
+	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
+}
+
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
+
+/*
+ * This structure is stuffed into the struct file's private_data field
+ * for directories.  It is where we put information so that we can do
+ * readdir operations in hash tree order.
+ */
+struct dir_private_info {
+	struct rb_root	root;
+	struct rb_node	*curr_node;
+	struct fname	*extra_fname;
+	loff_t		last_pos;
+	__u32		curr_hash;
+	__u32		curr_minor_hash;
+	__u32		next_hash;
+};
+
+/* calculate the first block number of the group */
+static inline ext4_fsblk_t
+ext4_group_first_block_no(struct super_block *sb, ext4_group_t group_no)
+{
+	return group_no * (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
+}
+
+/*
+ * Special error return code only used by dx_probe() and its callers.
+ */
+#define ERR_BAD_DX_DIR	(-(MAX_ERRNO - 1))
+
+/* htree levels for ext4 */
+#define	EXT4_HTREE_LEVEL_COMPAT	2
+#define	EXT4_HTREE_LEVEL	3
+
+static inline int ext4_dir_htree_level(struct super_block *sb)
+{
+	return ext4_has_feature_largedir(sb) ?
+		EXT4_HTREE_LEVEL : EXT4_HTREE_LEVEL_COMPAT;
+}
+
+/*
+ * Timeout and state flag for lazy initialization inode thread.
+ */
+#define EXT4_DEF_LI_WAIT_MULT			10
+#define EXT4_DEF_LI_MAX_START_DELAY		5
+#define EXT4_LAZYINIT_QUIT			0x0001
+#define EXT4_LAZYINIT_RUNNING			0x0002
+
+/*
+ * Lazy inode table initialization info
+ */
+struct ext4_lazy_init {
+	unsigned long		li_state;
+	struct list_head	li_request_list;
+	struct mutex		li_list_mtx;
+};
+
+enum ext4_li_mode {
+	EXT4_LI_MODE_PREFETCH_BBITMAP,
+	EXT4_LI_MODE_ITABLE,
+};
+
+struct ext4_li_request {
+	struct super_block	*lr_super;
+	enum ext4_li_mode	lr_mode;
+	ext4_group_t		lr_first_not_zeroed;
+	ext4_group_t		lr_next_group;
+	struct list_head	lr_request;
+	unsigned long		lr_next_sched;
+	unsigned long		lr_timeout;
+};
+
+struct ext4_features {
+	struct kobject f_kobj;
+	struct completion f_kobj_unregister;
+};
+
+/*
+ * This structure will be used for multiple mount protection. It will be
+ * written into the block number saved in the s_mmp_block field in the
+ * superblock. Programs that check MMP should assume that if
+ * SEQ_FSCK (or any unknown code above SEQ_MAX) is present then it is NOT safe
+ * to use the filesystem, regardless of how old the timestamp is.
+ */
+#define EXT4_MMP_MAGIC     0x004D4D50U /* ASCII for MMP */
+#define EXT4_MMP_SEQ_CLEAN 0xFF4D4D50U /* mmp_seq value for clean unmount */
+#define EXT4_MMP_SEQ_FSCK  0xE24D4D50U /* mmp_seq value when being fscked */
+#define EXT4_MMP_SEQ_MAX   0xE24D4D4FU /* maximum valid mmp_seq value */
+
+struct mmp_struct {
+	__le32	mmp_magic;		/* Magic number for MMP */
+	__le32	mmp_seq;		/* Sequence no. updated periodically */
+
+	/*
+	 * mmp_time, mmp_nodename & mmp_bdevname are only used for information
+	 * purposes and do not affect the correctness of the algorithm
+	 */
+	__le64	mmp_time;		/* Time last updated */
+	char	mmp_nodename[64];	/* Node which last updated MMP block */
+	char	mmp_bdevname[32];	/* Bdev which last updated MMP block */
+
+	/*
+	 * mmp_check_interval is used to verify if the MMP block has been
+	 * updated on the block device. The value is updated based on the
+	 * maximum time to write the MMP block during an update cycle.
+	 */
+	__le16	mmp_check_interval;
+
+	__le16	mmp_pad1;
+	__le32	mmp_pad2[226];
+	__le32	mmp_checksum;		/* crc32c(uuid+mmp_block) */
+};
+
+/* arguments passed to the mmp thread */
+struct mmpd_data {
+	struct buffer_head *bh; /* bh from initial read_mmp_block() */
+	struct super_block *sb;  /* super block of the fs */
+};
+
+/*
+ * Check interval multiplier
+ * The MMP block is written every update interval and initially checked every
+ * update interval x the multiplier (the value is then adapted based on the
+ * write latency). The reason is that writes can be delayed under load and we
+ * don't want readers to incorrectly assume that the filesystem is no longer
+ * in use.
+ */
+#define EXT4_MMP_CHECK_MULT		2UL
+
+/*
+ * Minimum interval for MMP checking in seconds.
+ */
+#define EXT4_MMP_MIN_CHECK_INTERVAL	5UL
+
+/*
+ * Maximum interval for MMP checking in seconds.
+ */
+#define EXT4_MMP_MAX_CHECK_INTERVAL	300UL
+
+/*
+ * Function prototypes
+ */
+
+/*
+ * Ok, these declarations are also in <linux/kernel.h> but none of the
+ * ext4 source programs needs to include it so they are duplicated here.
+ */
+# define NORET_TYPE	/**/
+# define ATTRIB_NORET	__attribute__((noreturn))
+# define NORET_AND	noreturn,
+
+/* bitmap.c */
+extern unsigned int ext4_count_free(char *bitmap, unsigned numchars);
+void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh, int sz);
+int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh, int sz);
+void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh);
+int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh);
+
+/* balloc.c */
+extern void ext4_get_group_no_and_offset(struct super_block *sb,
+					 ext4_fsblk_t blocknr,
+					 ext4_group_t *blockgrpp,
+					 ext4_grpblk_t *offsetp);
+extern ext4_group_t ext4_get_group_number(struct super_block *sb,
+					  ext4_fsblk_t block);
+
+extern unsigned int ext4_block_group(struct super_block *sb,
+			ext4_fsblk_t blocknr);
+extern ext4_grpblk_t ext4_block_group_offset(struct super_block *sb,
+			ext4_fsblk_t blocknr);
+extern int ext4_bg_has_super(struct super_block *sb, ext4_group_t group);
+extern unsigned long ext4_bg_num_gdb(struct super_block *sb,
+			ext4_group_t group);
+extern ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
+					 ext4_fsblk_t goal,
+					 unsigned int flags,
+					 unsigned long *count,
+					 int *errp);
+extern int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
+				    s64 nclusters, unsigned int flags);
+extern ext4_fsblk_t ext4_count_free_clusters(struct super_block *);
+extern void ext4_check_blocks_bitmap(struct super_block *);
+extern struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,
+						    ext4_group_t block_group,
+						    struct buffer_head ** bh);
+extern struct ext4_group_info *ext4_get_group_info(struct super_block *sb,
+						   ext4_group_t group);
+extern int ext4_should_retry_alloc(struct super_block *sb, int *retries);
+
+extern struct buffer_head *ext4_read_block_bitmap_nowait(struct super_block *sb,
+						ext4_group_t block_group,
+						bool ignore_locked);
+extern int ext4_wait_block_bitmap(struct super_block *sb,
+				  ext4_group_t block_group,
+				  struct buffer_head *bh);
+extern struct buffer_head *ext4_read_block_bitmap(struct super_block *sb,
+						  ext4_group_t block_group);
+extern unsigned ext4_free_clusters_after_init(struct super_block *sb,
+					      ext4_group_t block_group,
+					      struct ext4_group_desc *gdp);
+ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
+
+#ifdef CONFIG_UNICODE
+extern void ext4_fname_setup_ci_filename(struct inode *dir,
+					 const struct qstr *iname,
+					 struct fscrypt_str *fname);
+#endif
+
+#ifdef CONFIG_FS_ENCRYPTION
+static inline void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
+						const struct fscrypt_name *src)
+{
+	memset(dst, 0, sizeof(*dst));
+
+	dst->usr_fname = src->usr_fname;
+	dst->disk_name = src->disk_name;
+	dst->hinfo.hash = src->hash;
+	dst->hinfo.minor_hash = src->minor_hash;
+	dst->crypto_buf = src->crypto_buf;
+}
+
+static inline int ext4_fname_setup_filename(struct inode *dir,
+					    const struct qstr *iname,
+					    int lookup,
+					    struct ext4_filename *fname)
+{
+	struct fscrypt_name name;
+	int err;
+
+	err = fscrypt_setup_filename(dir, iname, lookup, &name);
+	if (err)
+		return err;
+
+	ext4_fname_from_fscrypt_name(fname, &name);
+
+#ifdef CONFIG_UNICODE
+	ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name);
+#endif
+	return 0;
+}
+
+static inline int ext4_fname_prepare_lookup(struct inode *dir,
+					    struct dentry *dentry,
+					    struct ext4_filename *fname)
+{
+	struct fscrypt_name name;
+	int err;
+
+	err = fscrypt_prepare_lookup(dir, dentry, &name);
+	if (err)
+		return err;
+
+	ext4_fname_from_fscrypt_name(fname, &name);
+
+#ifdef CONFIG_UNICODE
+	ext4_fname_setup_ci_filename(dir, &dentry->d_name, &fname->cf_name);
+#endif
+	return 0;
+}
+
+static inline void ext4_fname_free_filename(struct ext4_filename *fname)
+{
+	struct fscrypt_name name;
+
+	name.crypto_buf = fname->crypto_buf;
+	fscrypt_free_filename(&name);
+
+	fname->crypto_buf.name = NULL;
+	fname->usr_fname = NULL;
+	fname->disk_name.name = NULL;
+
+#ifdef CONFIG_UNICODE
+	kfree(fname->cf_name.name);
+	fname->cf_name.name = NULL;
+#endif
+}
+#else /* !CONFIG_FS_ENCRYPTION */
+static inline int ext4_fname_setup_filename(struct inode *dir,
+					    const struct qstr *iname,
+					    int lookup,
+					    struct ext4_filename *fname)
+{
+	fname->usr_fname = iname;
+	fname->disk_name.name = (unsigned char *) iname->name;
+	fname->disk_name.len = iname->len;
+
+#ifdef CONFIG_UNICODE
+	ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name);
+#endif
+
+	return 0;
+}
+
+static inline int ext4_fname_prepare_lookup(struct inode *dir,
+					    struct dentry *dentry,
+					    struct ext4_filename *fname)
+{
+	return ext4_fname_setup_filename(dir, &dentry->d_name, 1, fname);
+}
+
+static inline void ext4_fname_free_filename(struct ext4_filename *fname)
+{
+#ifdef CONFIG_UNICODE
+	kfree(fname->cf_name.name);
+	fname->cf_name.name = NULL;
+#endif
+}
+#endif /* !CONFIG_FS_ENCRYPTION */
+
+/* dir.c */
+extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
+				  struct file *,
+				  struct ext4_dir_entry_2 *,
+				  struct buffer_head *, char *, int,
+				  unsigned int);
+#define ext4_check_dir_entry(dir, filp, de, bh, buf, size, offset)	\
+	unlikely(__ext4_check_dir_entry(__func__, __LINE__, (dir), (filp), \
+					(de), (bh), (buf), (size), (offset)))
+extern int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
+				__u32 minor_hash,
+				struct ext4_dir_entry_2 *dirent,
+				struct fscrypt_str *ent_name);
+extern void ext4_htree_free_dir_info(struct dir_private_info *p);
+extern int ext4_find_dest_de(struct inode *dir, struct inode *inode,
+			     struct buffer_head *bh,
+			     void *buf, int buf_size,
+			     struct ext4_filename *fname,
+			     struct ext4_dir_entry_2 **dest_de);
+void ext4_insert_dentry(struct inode *inode,
+			struct ext4_dir_entry_2 *de,
+			int buf_size,
+			struct ext4_filename *fname);
+static inline void ext4_update_dx_flag(struct inode *inode)
+{
+	if (!ext4_has_feature_dir_index(inode->i_sb) &&
+	    ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
+		/* ext4_iget() should have caught this... */
+		WARN_ON_ONCE(ext4_has_feature_metadata_csum(inode->i_sb));
+		ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
+	}
+}
+static const unsigned char ext4_filetype_table[] = {
+	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
+};
+
+static inline  unsigned char get_dtype(struct super_block *sb, int filetype)
+{
+	if (!ext4_has_feature_filetype(sb) || filetype >= EXT4_FT_MAX)
+		return DT_UNKNOWN;
+
+	return ext4_filetype_table[filetype];
+}
+extern int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
+			     void *buf, int buf_size);
+
+/* fsync.c */
+extern int ext4_sync_file(struct file *, loff_t, loff_t, int);
+
+/* hash.c */
+extern int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
+			  struct dx_hash_info *hinfo);
+
+/* ialloc.c */
+extern int ext4_mark_inode_used(struct super_block *sb, int ino);
+extern struct inode *__ext4_new_inode(handle_t *, struct inode *, umode_t,
+				      const struct qstr *qstr, __u32 goal,
+				      uid_t *owner, __u32 i_flags,
+				      int handle_type, unsigned int line_no,
+				      int nblocks);
+
+#define ext4_new_inode(handle, dir, mode, qstr, goal, owner, i_flags) \
+	__ext4_new_inode((handle), (dir), (mode), (qstr), (goal), (owner), \
+			 i_flags, 0, 0, 0)
+#define ext4_new_inode_start_handle(dir, mode, qstr, goal, owner, \
+				    type, nblocks)		    \
+	__ext4_new_inode(NULL, (dir), (mode), (qstr), (goal), (owner), \
+			 0, (type), __LINE__, (nblocks))
+
+
+extern void ext4_free_inode(handle_t *, struct inode *);
+extern struct inode * ext4_orphan_get(struct super_block *, unsigned long);
+extern unsigned long ext4_count_free_inodes(struct super_block *);
+extern unsigned long ext4_count_dirs(struct super_block *);
+extern void ext4_check_inodes_bitmap(struct super_block *);
+extern void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap);
+extern int ext4_init_inode_table(struct super_block *sb,
+				 ext4_group_t group, int barrier);
+extern void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate);
+
+/* fast_commit.c */
+int ext4_fc_info_show(struct seq_file *seq, void *v);
+void ext4_fc_init(struct super_block *sb, journal_t *journal);
+void ext4_fc_init_inode(struct inode *inode);
+void ext4_fc_track_range(handle_t *handle, struct inode *inode, ext4_lblk_t start,
+			 ext4_lblk_t end);
+void __ext4_fc_track_unlink(handle_t *handle, struct inode *inode,
+	struct dentry *dentry);
+void __ext4_fc_track_link(handle_t *handle, struct inode *inode,
+	struct dentry *dentry);
+void ext4_fc_track_unlink(handle_t *handle, struct dentry *dentry);
+void ext4_fc_track_link(handle_t *handle, struct dentry *dentry);
+void __ext4_fc_track_create(handle_t *handle, struct inode *inode,
+			    struct dentry *dentry);
+void ext4_fc_track_create(handle_t *handle, struct dentry *dentry);
+void ext4_fc_track_inode(handle_t *handle, struct inode *inode);
+void ext4_fc_mark_ineligible(struct super_block *sb, int reason);
+void ext4_fc_start_ineligible(struct super_block *sb, int reason);
+void ext4_fc_stop_ineligible(struct super_block *sb);
+void ext4_fc_start_update(struct inode *inode);
+void ext4_fc_stop_update(struct inode *inode);
+void ext4_fc_del(struct inode *inode);
+bool ext4_fc_replay_check_excluded(struct super_block *sb, ext4_fsblk_t block);
+void ext4_fc_replay_cleanup(struct super_block *sb);
+int ext4_fc_commit(journal_t *journal, tid_t commit_tid);
+int __init ext4_fc_init_dentry_cache(void);
+void ext4_fc_destroy_dentry_cache(void);
+int ext4_fc_record_regions(struct super_block *sb, int ino,
+			   ext4_lblk_t lblk, ext4_fsblk_t pblk,
+			   int len, int replay);
+
+/* mballoc.c */
+extern const struct seq_operations ext4_mb_seq_groups_ops;
+extern long ext4_mb_stats;
+extern long ext4_mb_max_to_scan;
+extern int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset);
+extern int ext4_mb_init(struct super_block *);
+extern int ext4_mb_release(struct super_block *);
+extern ext4_fsblk_t ext4_mb_new_blocks(handle_t *,
+				struct ext4_allocation_request *, int *);
+extern int ext4_mb_reserve_blocks(struct super_block *, int);
+extern void ext4_discard_preallocations(struct inode *, unsigned int);
+extern int __init ext4_init_mballoc(void);
+extern void ext4_exit_mballoc(void);
+extern ext4_group_t ext4_mb_prefetch(struct super_block *sb,
+				     ext4_group_t group,
+				     unsigned int nr, int *cnt);
+extern void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
+				  unsigned int nr);
+
+extern void ext4_free_blocks(handle_t *handle, struct inode *inode,
+			     struct buffer_head *bh, ext4_fsblk_t block,
+			     unsigned long count, int flags);
+extern int ext4_mb_alloc_groupinfo(struct super_block *sb,
+				   ext4_group_t ngroups);
+extern int ext4_mb_add_groupinfo(struct super_block *sb,
+		ext4_group_t i, struct ext4_group_desc *desc);
+extern int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
+				ext4_fsblk_t block, unsigned long count);
+extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
+extern void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid);
+extern void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
+		       int len, int state);
+
+/* inode.c */
+void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
+			 struct ext4_inode_info *ei);
+int ext4_inode_is_fast_symlink(struct inode *inode);
+struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
+struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int);
+int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
+		     bool wait, struct buffer_head **bhs);
+int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
+			     struct buffer_head *bh_result, int create);
+int ext4_get_block(struct inode *inode, sector_t iblock,
+		   struct buffer_head *bh_result, int create);
+int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
+			   struct buffer_head *bh, int create);
+int ext4_walk_page_buffers(handle_t *handle,
+			   struct buffer_head *head,
+			   unsigned from,
+			   unsigned to,
+			   int *partial,
+			   int (*fn)(handle_t *handle,
+				     struct buffer_head *bh));
+int do_journal_get_write_access(handle_t *handle,
+				struct buffer_head *bh);
+#define FALL_BACK_TO_NONDELALLOC 1
+#define CONVERT_INLINE_DATA	 2
+
+typedef enum {
+	EXT4_IGET_NORMAL =	0,
+	EXT4_IGET_SPECIAL =	0x0001, /* OK to iget a system inode */
+	EXT4_IGET_HANDLE = 	0x0002,	/* Inode # is from a handle */
+	EXT4_IGET_BAD =		0x0004, /* Allow to iget a bad inode */
+	EXT4_IGET_EA_INODE =	0x0008	/* Inode should contain an EA value */
+} ext4_iget_flags;
+
+extern struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
+				 ext4_iget_flags flags, const char *function,
+				 unsigned int line);
+
+#define ext4_iget(sb, ino, flags) \
+	__ext4_iget((sb), (ino), (flags), __func__, __LINE__)
+
+extern int  ext4_write_inode(struct inode *, struct writeback_control *);
+extern int  ext4_setattr(struct dentry *, struct iattr *);
+extern int  ext4_getattr(const struct path *, struct kstat *, u32, unsigned int);
+extern void ext4_evict_inode(struct inode *);
+extern void ext4_clear_inode(struct inode *);
+extern int  ext4_file_getattr(const struct path *, struct kstat *, u32, unsigned int);
+extern int  ext4_sync_inode(handle_t *, struct inode *);
+extern void ext4_dirty_inode(struct inode *, int);
+extern int ext4_change_inode_journal_flag(struct inode *, int);
+extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *);
+extern int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
+			  struct ext4_iloc *iloc);
+extern int ext4_inode_attach_jinode(struct inode *inode);
+extern int ext4_can_truncate(struct inode *inode);
+extern int ext4_truncate(struct inode *);
+extern int ext4_break_layouts(struct inode *);
+extern int ext4_punch_hole(struct file *file, loff_t offset, loff_t length);
+extern void ext4_set_inode_flags(struct inode *, bool init);
+extern int ext4_alloc_da_blocks(struct inode *inode);
+extern void ext4_set_aops(struct inode *inode);
+extern int ext4_writepage_trans_blocks(struct inode *);
+extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
+extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
+			     loff_t lstart, loff_t lend);
+extern vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf);
+extern vm_fault_t ext4_filemap_fault(struct vm_fault *vmf);
+extern qsize_t *ext4_get_reserved_space(struct inode *inode);
+extern int ext4_get_projid(struct inode *inode, kprojid_t *projid);
+extern void ext4_da_release_space(struct inode *inode, int to_free);
+extern void ext4_da_update_reserve_space(struct inode *inode,
+					int used, int quota_claim);
+extern int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk,
+			      ext4_fsblk_t pblk, ext4_lblk_t len);
+
+/* indirect.c */
+extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
+				struct ext4_map_blocks *map, int flags);
+extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks);
+extern void ext4_ind_truncate(handle_t *, struct inode *inode);
+extern int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
+				 ext4_lblk_t start, ext4_lblk_t end);
+
+/* ioctl.c */
+extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
+extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);
+extern void ext4_reset_inode_seed(struct inode *inode);
+
+/* migrate.c */
+extern int ext4_ext_migrate(struct inode *);
+extern int ext4_ind_migrate(struct inode *inode);
+
+/* namei.c */
+extern int ext4_init_new_dir(handle_t *handle, struct inode *dir,
+			     struct inode *inode);
+extern int ext4_dirblock_csum_verify(struct inode *inode,
+				     struct buffer_head *bh);
+extern int ext4_orphan_add(handle_t *, struct inode *);
+extern int ext4_orphan_del(handle_t *, struct inode *);
+extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
+				__u32 start_minor_hash, __u32 *next_hash);
+extern int ext4_search_dir(struct buffer_head *bh,
+			   char *search_buf,
+			   int buf_size,
+			   struct inode *dir,
+			   struct ext4_filename *fname,
+			   unsigned int offset,
+			   struct ext4_dir_entry_2 **res_dir);
+extern int ext4_generic_delete_entry(struct inode *dir,
+				     struct ext4_dir_entry_2 *de_del,
+				     struct buffer_head *bh,
+				     void *entry_buf,
+				     int buf_size,
+				     int csum_size);
+extern bool ext4_empty_dir(struct inode *inode);
+
+/* resize.c */
+extern void ext4_kvfree_array_rcu(void *to_free);
+extern int ext4_group_add(struct super_block *sb,
+				struct ext4_new_group_data *input);
+extern int ext4_group_extend(struct super_block *sb,
+				struct ext4_super_block *es,
+				ext4_fsblk_t n_blocks_count);
+extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);
+
+/* super.c */
+extern struct buffer_head *ext4_sb_bread(struct super_block *sb,
+					 sector_t block, int op_flags);
+extern struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,
+						   sector_t block);
+extern void ext4_read_bh_nowait(struct buffer_head *bh, int op_flags,
+				bh_end_io_t *end_io);
+extern int ext4_read_bh(struct buffer_head *bh, int op_flags,
+			bh_end_io_t *end_io);
+extern int ext4_read_bh_lock(struct buffer_head *bh, int op_flags, bool wait);
+extern void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block);
+extern int ext4_seq_options_show(struct seq_file *seq, void *offset);
+extern int ext4_calculate_overhead(struct super_block *sb);
+extern void ext4_superblock_csum_set(struct super_block *sb);
+extern int ext4_alloc_flex_bg_array(struct super_block *sb,
+				    ext4_group_t ngroup);
+extern const char *ext4_decode_error(struct super_block *sb, int errno,
+				     char nbuf[16]);
+extern void ext4_mark_group_bitmap_corrupted(struct super_block *sb,
+					     ext4_group_t block_group,
+					     unsigned int flags);
+extern unsigned int ext4_num_base_meta_blocks(struct super_block *sb,
+					      ext4_group_t block_group);
+
+extern __printf(6, 7)
+void __ext4_error(struct super_block *, const char *, unsigned int, int, __u64,
+		  const char *, ...);
+extern __printf(6, 7)
+void __ext4_error_inode(struct inode *, const char *, unsigned int,
+			ext4_fsblk_t, int, const char *, ...);
+extern __printf(5, 6)
+void __ext4_error_file(struct file *, const char *, unsigned int, ext4_fsblk_t,
+		     const char *, ...);
+extern void __ext4_std_error(struct super_block *, const char *,
+			     unsigned int, int);
+extern __printf(5, 6)
+void __ext4_abort(struct super_block *, const char *, unsigned int, int,
+		  const char *, ...);
+extern __printf(4, 5)
+void __ext4_warning(struct super_block *, const char *, unsigned int,
+		    const char *, ...);
+extern __printf(4, 5)
+void __ext4_warning_inode(const struct inode *inode, const char *function,
+			  unsigned int line, const char *fmt, ...);
+extern __printf(3, 4)
+void __ext4_msg(struct super_block *, const char *, const char *, ...);
+extern void __dump_mmp_msg(struct super_block *, struct mmp_struct *mmp,
+			   const char *, unsigned int, const char *);
+extern __printf(7, 8)
+void __ext4_grp_locked_error(const char *, unsigned int,
+			     struct super_block *, ext4_group_t,
+			     unsigned long, ext4_fsblk_t,
+			     const char *, ...);
+
+#define EXT4_ERROR_INODE(inode, fmt, a...) \
+	ext4_error_inode((inode), __func__, __LINE__, 0, (fmt), ## a)
+
+#define EXT4_ERROR_INODE_ERR(inode, err, fmt, a...)			\
+	__ext4_error_inode((inode), __func__, __LINE__, 0, (err), (fmt), ## a)
+
+#define ext4_error_inode_block(inode, block, err, fmt, a...)		\
+	__ext4_error_inode((inode), __func__, __LINE__, (block), (err),	\
+			   (fmt), ## a)
+
+#define EXT4_ERROR_FILE(file, block, fmt, a...)				\
+	ext4_error_file((file), __func__, __LINE__, (block), (fmt), ## a)
+
+#ifdef CONFIG_PRINTK
+
+#define ext4_error_inode(inode, func, line, block, fmt, ...)		\
+	__ext4_error_inode(inode, func, line, block, 0, fmt, ##__VA_ARGS__)
+#define ext4_error_inode_err(inode, func, line, block, err, fmt, ...)	\
+	__ext4_error_inode((inode), (func), (line), (block), 		\
+			   (err), (fmt), ##__VA_ARGS__)
+#define ext4_error_file(file, func, line, block, fmt, ...)		\
+	__ext4_error_file(file, func, line, block, fmt, ##__VA_ARGS__)
+#define ext4_error(sb, fmt, ...)					\
+	__ext4_error((sb), __func__, __LINE__, 0, 0, (fmt), ##__VA_ARGS__)
+#define ext4_error_err(sb, err, fmt, ...)				\
+	__ext4_error((sb), __func__, __LINE__, (err), 0, (fmt), ##__VA_ARGS__)
+#define ext4_abort(sb, err, fmt, ...)					\
+	__ext4_abort((sb), __func__, __LINE__, (err), (fmt), ##__VA_ARGS__)
+#define ext4_warning(sb, fmt, ...)					\
+	__ext4_warning(sb, __func__, __LINE__, fmt, ##__VA_ARGS__)
+#define ext4_warning_inode(inode, fmt, ...)				\
+	__ext4_warning_inode(inode, __func__, __LINE__, fmt, ##__VA_ARGS__)
+#define ext4_msg(sb, level, fmt, ...)				\
+	__ext4_msg(sb, level, fmt, ##__VA_ARGS__)
+#define dump_mmp_msg(sb, mmp, msg)					\
+	__dump_mmp_msg(sb, mmp, __func__, __LINE__, msg)
+#define ext4_grp_locked_error(sb, grp, ino, block, fmt, ...)		\
+	__ext4_grp_locked_error(__func__, __LINE__, sb, grp, ino, block, \
+				fmt, ##__VA_ARGS__)
+
+#else
+
+#define ext4_error_inode(inode, func, line, block, fmt, ...)		\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_error_inode(inode, "", 0, block, 0, " ");		\
+} while (0)
+#define ext4_error_inode_err(inode, func, line, block, err, fmt, ...)	\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_error_inode(inode, "", 0, block, err, " ");		\
+} while (0)
+#define ext4_error_file(file, func, line, block, fmt, ...)		\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_error_file(file, "", 0, block, " ");			\
+} while (0)
+#define ext4_error(sb, fmt, ...)					\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_error(sb, "", 0, 0, 0, " ");				\
+} while (0)
+#define ext4_error_err(sb, err, fmt, ...)				\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_error(sb, "", 0, err, 0, " ");				\
+} while (0)
+#define ext4_abort(sb, err, fmt, ...)					\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_abort(sb, "", 0, err, " ");				\
+} while (0)
+#define ext4_warning(sb, fmt, ...)					\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_warning(sb, "", 0, " ");					\
+} while (0)
+#define ext4_warning_inode(inode, fmt, ...)				\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_warning_inode(inode, "", 0, " ");			\
+} while (0)
+#define ext4_msg(sb, level, fmt, ...)					\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);					\
+	__ext4_msg(sb, "", " ");					\
+} while (0)
+#define dump_mmp_msg(sb, mmp, msg)					\
+	__dump_mmp_msg(sb, mmp, "", 0, "")
+#define ext4_grp_locked_error(sb, grp, ino, block, fmt, ...)		\
+do {									\
+	no_printk(fmt, ##__VA_ARGS__);				\
+	__ext4_grp_locked_error("", 0, sb, grp, ino, block, " ");	\
+} while (0)
+
+#endif
+
+extern ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
+				      struct ext4_group_desc *bg);
+extern ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
+				      struct ext4_group_desc *bg);
+extern ext4_fsblk_t ext4_inode_table(struct super_block *sb,
+				     struct ext4_group_desc *bg);
+extern __u32 ext4_free_group_clusters(struct super_block *sb,
+				      struct ext4_group_desc *bg);
+extern __u32 ext4_free_inodes_count(struct super_block *sb,
+				 struct ext4_group_desc *bg);
+extern __u32 ext4_used_dirs_count(struct super_block *sb,
+				struct ext4_group_desc *bg);
+extern __u32 ext4_itable_unused_count(struct super_block *sb,
+				   struct ext4_group_desc *bg);
+extern void ext4_block_bitmap_set(struct super_block *sb,
+				  struct ext4_group_desc *bg, ext4_fsblk_t blk);
+extern void ext4_inode_bitmap_set(struct super_block *sb,
+				  struct ext4_group_desc *bg, ext4_fsblk_t blk);
+extern void ext4_inode_table_set(struct super_block *sb,
+				 struct ext4_group_desc *bg, ext4_fsblk_t blk);
+extern void ext4_free_group_clusters_set(struct super_block *sb,
+					 struct ext4_group_desc *bg,
+					 __u32 count);
+extern void ext4_free_inodes_set(struct super_block *sb,
+				struct ext4_group_desc *bg, __u32 count);
+extern void ext4_used_dirs_set(struct super_block *sb,
+				struct ext4_group_desc *bg, __u32 count);
+extern void ext4_itable_unused_set(struct super_block *sb,
+				   struct ext4_group_desc *bg, __u32 count);
+extern int ext4_group_desc_csum_verify(struct super_block *sb, __u32 group,
+				       struct ext4_group_desc *gdp);
+extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
+				     struct ext4_group_desc *gdp);
+extern int ext4_register_li_request(struct super_block *sb,
+				    ext4_group_t first_not_zeroed);
+
+static inline int ext4_has_metadata_csum(struct super_block *sb)
+{
+	WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
+		     !EXT4_SB(sb)->s_chksum_driver);
+
+	return ext4_has_feature_metadata_csum(sb) &&
+	       (EXT4_SB(sb)->s_chksum_driver != NULL);
+}
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+	return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
+#define ext4_read_incompat_64bit_val(es, name) \
+	(((es)->s_feature_incompat & cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT) \
+		? (ext4_fsblk_t)le32_to_cpu(es->name##_hi) << 32 : 0) | \
+		le32_to_cpu(es->name##_lo))
+
+static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
+{
+	return ext4_read_incompat_64bit_val(es, s_blocks_count);
+}
+
+static inline ext4_fsblk_t ext4_r_blocks_count(struct ext4_super_block *es)
+{
+	return ext4_read_incompat_64bit_val(es, s_r_blocks_count);
+}
+
+static inline ext4_fsblk_t ext4_free_blocks_count(struct ext4_super_block *es)
+{
+	return ext4_read_incompat_64bit_val(es, s_free_blocks_count);
+}
+
+static inline void ext4_blocks_count_set(struct ext4_super_block *es,
+					 ext4_fsblk_t blk)
+{
+	es->s_blocks_count_lo = cpu_to_le32((u32)blk);
+	es->s_blocks_count_hi = cpu_to_le32(blk >> 32);
+}
+
+static inline void ext4_free_blocks_count_set(struct ext4_super_block *es,
+					      ext4_fsblk_t blk)
+{
+	es->s_free_blocks_count_lo = cpu_to_le32((u32)blk);
+	es->s_free_blocks_count_hi = cpu_to_le32(blk >> 32);
+}
+
+static inline void ext4_r_blocks_count_set(struct ext4_super_block *es,
+					   ext4_fsblk_t blk)
+{
+	es->s_r_blocks_count_lo = cpu_to_le32((u32)blk);
+	es->s_r_blocks_count_hi = cpu_to_le32(blk >> 32);
+}
+
+static inline loff_t ext4_isize(struct super_block *sb,
+				struct ext4_inode *raw_inode)
+{
+	if (ext4_has_feature_largedir(sb) ||
+	    S_ISREG(le16_to_cpu(raw_inode->i_mode)))
+		return ((loff_t)le32_to_cpu(raw_inode->i_size_high) << 32) |
+			le32_to_cpu(raw_inode->i_size_lo);
+
+	return (loff_t) le32_to_cpu(raw_inode->i_size_lo);
+}
+
+static inline void ext4_isize_set(struct ext4_inode *raw_inode, loff_t i_size)
+{
+	raw_inode->i_size_lo = cpu_to_le32(i_size);
+	raw_inode->i_size_high = cpu_to_le32(i_size >> 32);
+}
+
+/*
+ * Reading s_groups_count requires using smp_rmb() afterwards.  See
+ * the locking protocol documented in the comments of ext4_group_add()
+ * in resize.c
+ */
+static inline ext4_group_t ext4_get_groups_count(struct super_block *sb)
+{
+	ext4_group_t	ngroups = EXT4_SB(sb)->s_groups_count;
+
+	smp_rmb();
+	return ngroups;
+}
+
+static inline ext4_group_t ext4_flex_group(struct ext4_sb_info *sbi,
+					     ext4_group_t block_group)
+{
+	return block_group >> sbi->s_log_groups_per_flex;
+}
+
+static inline unsigned int ext4_flex_bg_size(struct ext4_sb_info *sbi)
+{
+	return 1 << sbi->s_log_groups_per_flex;
+}
+
+#define ext4_std_error(sb, errno)				\
+do {								\
+	if ((errno))						\
+		__ext4_std_error((sb), __func__, __LINE__, (errno));	\
+} while (0)
+
+#ifdef CONFIG_SMP
+/* Each CPU can accumulate percpu_counter_batch clusters in their local
+ * counters. So we need to make sure we have free clusters more
+ * than percpu_counter_batch  * nr_cpu_ids. Also add a window of 4 times.
+ */
+#define EXT4_FREECLUSTERS_WATERMARK (4 * (percpu_counter_batch * nr_cpu_ids))
+#else
+#define EXT4_FREECLUSTERS_WATERMARK 0
+#endif
+
+/* Update i_disksize. Requires i_mutex to avoid races with truncate */
+static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)
+{
+	WARN_ON_ONCE(S_ISREG(inode->i_mode) &&
+		     !inode_is_locked(inode));
+	down_write(&EXT4_I(inode)->i_data_sem);
+	if (newsize > EXT4_I(inode)->i_disksize)
+		WRITE_ONCE(EXT4_I(inode)->i_disksize, newsize);
+	up_write(&EXT4_I(inode)->i_data_sem);
+}
+
+/* Update i_size, i_disksize. Requires i_mutex to avoid races with truncate */
+static inline int ext4_update_inode_size(struct inode *inode, loff_t newsize)
+{
+	int changed = 0;
+
+	if (newsize > inode->i_size) {
+		i_size_write(inode, newsize);
+		changed = 1;
+	}
+	if (newsize > EXT4_I(inode)->i_disksize) {
+		ext4_update_i_disksize(inode, newsize);
+		changed |= 2;
+	}
+	return changed;
+}
+
+int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
+				      loff_t len);
+
+struct ext4_group_info {
+	unsigned long   bb_state;
+#ifdef AGGRESSIVE_CHECK
+	unsigned long	bb_check_counter;
+#endif
+	struct rb_root  bb_free_root;
+	ext4_grpblk_t	bb_first_free;	/* first free block */
+	ext4_grpblk_t	bb_free;	/* total free blocks */
+	ext4_grpblk_t	bb_fragments;	/* nr of freespace fragments */
+	ext4_grpblk_t	bb_largest_free_order;/* order of largest frag in BG */
+	struct          list_head bb_prealloc_list;
+#ifdef DOUBLE_CHECK
+	void            *bb_bitmap;
+#endif
+	struct rw_semaphore alloc_sem;
+	ext4_grpblk_t	bb_counters[];	/* Nr of free power-of-two-block
+					 * regions, index is order.
+					 * bb_counters[3] = 5 means
+					 * 5 free 8-block regions. */
+};
+
+#define EXT4_GROUP_INFO_NEED_INIT_BIT		0
+#define EXT4_GROUP_INFO_WAS_TRIMMED_BIT		1
+#define EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT	2
+#define EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT	3
+#define EXT4_GROUP_INFO_BBITMAP_CORRUPT		\
+	(1 << EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT)
+#define EXT4_GROUP_INFO_IBITMAP_CORRUPT		\
+	(1 << EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT)
+#define EXT4_GROUP_INFO_BBITMAP_READ_BIT	4
+
+#define EXT4_MB_GRP_NEED_INIT(grp)	\
+	(test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_BBITMAP_CORRUPT(grp)	\
+	(test_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_IBITMAP_CORRUPT(grp)	\
+	(test_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &((grp)->bb_state)))
+
+#define EXT4_MB_GRP_WAS_TRIMMED(grp)	\
+	(test_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_SET_TRIMMED(grp)	\
+	(set_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_CLEAR_TRIMMED(grp)	\
+	(clear_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_TEST_AND_SET_READ(grp)	\
+	(test_and_set_bit(EXT4_GROUP_INFO_BBITMAP_READ_BIT, &((grp)->bb_state)))
+
+#define EXT4_MAX_CONTENTION		8
+#define EXT4_CONTENTION_THRESHOLD	2
+
+static inline spinlock_t *ext4_group_lock_ptr(struct super_block *sb,
+					      ext4_group_t group)
+{
+	return bgl_lock_ptr(EXT4_SB(sb)->s_blockgroup_lock, group);
+}
+
+/*
+ * Returns true if the filesystem is busy enough that attempts to
+ * access the block group locks has run into contention.
+ */
+static inline int ext4_fs_is_busy(struct ext4_sb_info *sbi)
+{
+	return (atomic_read(&sbi->s_lock_busy) > EXT4_CONTENTION_THRESHOLD);
+}
+
+static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
+{
+	spinlock_t *lock = ext4_group_lock_ptr(sb, group);
+	if (spin_trylock(lock))
+		/*
+		 * We're able to grab the lock right away, so drop the
+		 * lock contention counter.
+		 */
+		atomic_add_unless(&EXT4_SB(sb)->s_lock_busy, -1, 0);
+	else {
+		/*
+		 * The lock is busy, so bump the contention counter,
+		 * and then wait on the spin lock.
+		 */
+		atomic_add_unless(&EXT4_SB(sb)->s_lock_busy, 1,
+				  EXT4_MAX_CONTENTION);
+		spin_lock(lock);
+	}
+}
+
+static inline void ext4_unlock_group(struct super_block *sb,
+					ext4_group_t group)
+{
+	spin_unlock(ext4_group_lock_ptr(sb, group));
+}
+
+/*
+ * Block validity checking
+ */
+#define ext4_check_indirect_blockref(inode, bh)				\
+	ext4_check_blockref(__func__, __LINE__, inode,			\
+			    (__le32 *)(bh)->b_data,			\
+			    EXT4_ADDR_PER_BLOCK((inode)->i_sb))
+
+#define ext4_ind_check_inode(inode)					\
+	ext4_check_blockref(__func__, __LINE__, inode,			\
+			    EXT4_I(inode)->i_data,			\
+			    EXT4_NDIR_BLOCKS)
+
+/*
+ * Inodes and files operations
+ */
+
+/* dir.c */
+extern const struct file_operations ext4_dir_operations;
+
+#ifdef CONFIG_UNICODE
+extern const struct dentry_operations ext4_dentry_ops;
+#endif
+
+/* file.c */
+extern const struct inode_operations ext4_file_inode_operations;
+extern const struct file_operations ext4_file_operations;
+extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);
+
+/* inline.c */
+extern int ext4_get_max_inline_size(struct inode *inode);
+extern int ext4_find_inline_data_nolock(struct inode *inode);
+extern int ext4_init_inline_data(handle_t *handle, struct inode *inode,
+				 unsigned int len);
+extern int ext4_destroy_inline_data(handle_t *handle, struct inode *inode);
+
+extern int ext4_readpage_inline(struct inode *inode, struct page *page);
+extern int ext4_try_to_write_inline_data(struct address_space *mapping,
+					 struct inode *inode,
+					 loff_t pos, unsigned len,
+					 unsigned flags,
+					 struct page **pagep);
+extern int ext4_write_inline_data_end(struct inode *inode,
+				      loff_t pos, unsigned len,
+				      unsigned copied,
+				      struct page *page);
+extern struct buffer_head *
+ext4_journalled_write_inline_data(struct inode *inode,
+				  unsigned len,
+				  struct page *page);
+extern int ext4_da_write_inline_data_begin(struct address_space *mapping,
+					   struct inode *inode,
+					   loff_t pos, unsigned len,
+					   unsigned flags,
+					   struct page **pagep,
+					   void **fsdata);
+extern int ext4_da_write_inline_data_end(struct inode *inode, loff_t pos,
+					 unsigned len, unsigned copied,
+					 struct page *page);
+extern int ext4_try_add_inline_entry(handle_t *handle,
+				     struct ext4_filename *fname,
+				     struct inode *dir, struct inode *inode);
+extern int ext4_try_create_inline_dir(handle_t *handle,
+				      struct inode *parent,
+				      struct inode *inode);
+extern int ext4_read_inline_dir(struct file *filp,
+				struct dir_context *ctx,
+				int *has_inline_data);
+extern int ext4_inlinedir_to_tree(struct file *dir_file,
+				  struct inode *dir, ext4_lblk_t block,
+				  struct dx_hash_info *hinfo,
+				  __u32 start_hash, __u32 start_minor_hash,
+				  int *has_inline_data);
+extern struct buffer_head *ext4_find_inline_entry(struct inode *dir,
+					struct ext4_filename *fname,
+					struct ext4_dir_entry_2 **res_dir,
+					int *has_inline_data);
+extern int ext4_delete_inline_entry(handle_t *handle,
+				    struct inode *dir,
+				    struct ext4_dir_entry_2 *de_del,
+				    struct buffer_head *bh,
+				    int *has_inline_data);
+extern bool empty_inline_dir(struct inode *dir, int *has_inline_data);
+extern struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
+					struct ext4_dir_entry_2 **parent_de,
+					int *retval);
+extern int ext4_inline_data_fiemap(struct inode *inode,
+				   struct fiemap_extent_info *fieinfo,
+				   int *has_inline, __u64 start, __u64 len);
+
+struct iomap;
+extern int ext4_inline_data_iomap(struct inode *inode, struct iomap *iomap);
+
+extern int ext4_inline_data_truncate(struct inode *inode, int *has_inline);
+
+extern int ext4_convert_inline_data(struct inode *inode);
+
+static inline int ext4_has_inline_data(struct inode *inode)
+{
+	return ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA) &&
+	       EXT4_I(inode)->i_inline_off;
+}
+
+/* namei.c */
+extern const struct inode_operations ext4_dir_inode_operations;
+extern const struct inode_operations ext4_special_inode_operations;
+extern struct dentry *ext4_get_parent(struct dentry *child);
+extern struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
+				 struct ext4_dir_entry_2 *de,
+				 int blocksize, int csum_size,
+				 unsigned int parent_ino, int dotdot_real_len);
+extern void ext4_initialize_dirent_tail(struct buffer_head *bh,
+					unsigned int blocksize);
+extern int ext4_handle_dirty_dirblock(handle_t *handle, struct inode *inode,
+				      struct buffer_head *bh);
+extern int ext4_ci_compare(const struct inode *parent,
+			   const struct qstr *fname,
+			   const struct qstr *entry, bool quick);
+extern int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
+			 struct inode *inode, struct dentry *dentry);
+extern int __ext4_link(struct inode *dir, struct inode *inode,
+		       struct dentry *dentry);
+
+#define S_SHIFT 12
+static const unsigned char ext4_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = {
+	[S_IFREG >> S_SHIFT]	= EXT4_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= EXT4_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= EXT4_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= EXT4_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= EXT4_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= EXT4_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= EXT4_FT_SYMLINK,
+};
+
+static inline void ext4_set_de_type(struct super_block *sb,
+				struct ext4_dir_entry_2 *de,
+				umode_t mode) {
+	if (ext4_has_feature_filetype(sb))
+		de->file_type = ext4_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
+}
+
+/* readpages.c */
+extern int ext4_mpage_readpages(struct inode *inode,
+		struct readahead_control *rac, struct page *page);
+extern int __init ext4_init_post_read_processing(void);
+extern void ext4_exit_post_read_processing(void);
+
+/* symlink.c */
+extern const struct inode_operations ext4_encrypted_symlink_inode_operations;
+extern const struct inode_operations ext4_symlink_inode_operations;
+extern const struct inode_operations ext4_fast_symlink_inode_operations;
+
+/* sysfs.c */
+extern int ext4_register_sysfs(struct super_block *sb);
+extern void ext4_unregister_sysfs(struct super_block *sb);
+extern int __init ext4_init_sysfs(void);
+extern void ext4_exit_sysfs(void);
+
+/* block_validity */
+extern void ext4_release_system_zone(struct super_block *sb);
+extern int ext4_setup_system_zone(struct super_block *sb);
+extern int __init ext4_init_system_zone(void);
+extern void ext4_exit_system_zone(void);
+extern int ext4_inode_block_valid(struct inode *inode,
+				  ext4_fsblk_t start_blk,
+				  unsigned int count);
+extern int ext4_check_blockref(const char *, unsigned int,
+			       struct inode *, __le32 *, unsigned int);
+extern int ext4_sb_block_valid(struct super_block *sb, struct inode *inode,
+				ext4_fsblk_t start_blk, unsigned int count);
+
+
+/* extents.c */
+struct ext4_ext_path;
+struct ext4_extent;
+
+/*
+ * Maximum number of logical blocks in a file; ext4_extent's ee_block is
+ * __le32.
+ */
+#define EXT_MAX_BLOCKS	0xffffffff
+
+extern void ext4_ext_tree_init(handle_t *handle, struct inode *inode);
+extern int ext4_ext_index_trans_blocks(struct inode *inode, int extents);
+extern int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
+			       struct ext4_map_blocks *map, int flags);
+extern int ext4_ext_truncate(handle_t *, struct inode *);
+extern int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
+				 ext4_lblk_t end);
+extern void ext4_ext_init(struct super_block *);
+extern void ext4_ext_release(struct super_block *);
+extern long ext4_fallocate(struct file *file, int mode, loff_t offset,
+			  loff_t len);
+extern int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
+					  loff_t offset, ssize_t len);
+extern int ext4_convert_unwritten_io_end_vec(handle_t *handle,
+					     ext4_io_end_t *io_end);
+extern int ext4_map_blocks(handle_t *handle, struct inode *inode,
+			   struct ext4_map_blocks *map, int flags);
+extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
+						   int num,
+						   struct ext4_ext_path *path);
+extern int ext4_ext_insert_extent(handle_t *, struct inode *,
+				  struct ext4_ext_path **,
+				  struct ext4_extent *, int);
+extern struct ext4_ext_path *ext4_find_extent(struct inode *, ext4_lblk_t,
+					      struct ext4_ext_path **,
+					      int flags);
+extern void ext4_ext_drop_refs(struct ext4_ext_path *);
+extern int ext4_ext_check_inode(struct inode *inode);
+extern ext4_lblk_t ext4_ext_next_allocated_block(struct ext4_ext_path *path);
+extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+			__u64 start, __u64 len);
+extern int ext4_get_es_cache(struct inode *inode,
+			     struct fiemap_extent_info *fieinfo,
+			     __u64 start, __u64 len);
+extern int ext4_ext_precache(struct inode *inode);
+extern int ext4_swap_extents(handle_t *handle, struct inode *inode1,
+				struct inode *inode2, ext4_lblk_t lblk1,
+			     ext4_lblk_t lblk2,  ext4_lblk_t count,
+			     int mark_unwritten,int *err);
+extern int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu);
+extern int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
+				       int check_cred, int restart_cred,
+				       int revoke_cred);
+extern void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end);
+extern int ext4_ext_replay_set_iblocks(struct inode *inode);
+extern int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
+		int len, int unwritten, ext4_fsblk_t pblk);
+extern int ext4_ext_clear_bb(struct inode *inode);
+
+
+/* move_extent.c */
+extern void ext4_double_down_write_data_sem(struct inode *first,
+					    struct inode *second);
+extern void ext4_double_up_write_data_sem(struct inode *orig_inode,
+					  struct inode *donor_inode);
+extern int ext4_move_extents(struct file *o_filp, struct file *d_filp,
+			     __u64 start_orig, __u64 start_donor,
+			     __u64 len, __u64 *moved_len);
+
+/* page-io.c */
+extern int __init ext4_init_pageio(void);
+extern void ext4_exit_pageio(void);
+extern ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags);
+extern ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end);
+extern int ext4_put_io_end(ext4_io_end_t *io_end);
+extern void ext4_put_io_end_defer(ext4_io_end_t *io_end);
+extern void ext4_io_submit_init(struct ext4_io_submit *io,
+				struct writeback_control *wbc);
+extern void ext4_end_io_rsv_work(struct work_struct *work);
+extern void ext4_io_submit(struct ext4_io_submit *io);
+extern int ext4_bio_write_page(struct ext4_io_submit *io,
+			       struct page *page,
+			       int len,
+			       struct writeback_control *wbc,
+			       bool keep_towrite);
+extern struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end);
+extern struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end);
+
+/* mmp.c */
+extern int ext4_multi_mount_protect(struct super_block *, ext4_fsblk_t);
+
+/* mmp.c */
+extern void ext4_stop_mmpd(struct ext4_sb_info *sbi);
+
+/* verity.c */
+extern const struct fsverity_operations ext4_verityops;
+
+/*
+ * Add new method to test whether block and inode bitmaps are properly
+ * initialized. With uninit_bg reading the block from disk is not enough
+ * to mark the bitmap uptodate. We need to also zero-out the bitmap
+ */
+#define BH_BITMAP_UPTODATE BH_JBDPrivateStart
+
+static inline int bitmap_uptodate(struct buffer_head *bh)
+{
+	return (buffer_uptodate(bh) &&
+			test_bit(BH_BITMAP_UPTODATE, &(bh)->b_state));
+}
+static inline void set_bitmap_uptodate(struct buffer_head *bh)
+{
+	set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
+}
+
+#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
+
+/* For ioend & aio unwritten conversion wait queues */
+#define EXT4_WQ_HASH_SZ		37
+#define ext4_ioend_wq(v)   (&ext4__ioend_wq[((unsigned long)(v)) %\
+					    EXT4_WQ_HASH_SZ])
+extern wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
+
+extern int ext4_resize_begin(struct super_block *sb);
+extern void ext4_resize_end(struct super_block *sb);
+
+static inline void ext4_set_io_unwritten_flag(struct inode *inode,
+					      struct ext4_io_end *io_end)
+{
+	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
+		io_end->flag |= EXT4_IO_END_UNWRITTEN;
+		atomic_inc(&EXT4_I(inode)->i_unwritten);
+	}
+}
+
+static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
+{
+	struct inode *inode = io_end->inode;
+
+	if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+		io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
+		/* Wake up anyone waiting on unwritten extent conversion */
+		if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
+			wake_up_all(ext4_ioend_wq(inode));
+	}
+}
+
+extern const struct iomap_ops ext4_iomap_ops;
+extern const struct iomap_ops ext4_iomap_overwrite_ops;
+extern const struct iomap_ops ext4_iomap_report_ops;
+
+static inline int ext4_buffer_uptodate(struct buffer_head *bh)
+{
+	/*
+	 * If the buffer has the write error flag, we have failed
+	 * to write out data in the block.  In this  case, we don't
+	 * have to read the block because we may read the old data
+	 * successfully.
+	 */
+	if (!buffer_uptodate(bh) && buffer_write_io_error(bh))
+		set_buffer_uptodate(bh);
+	return buffer_uptodate(bh);
+}
+
+#endif	/* __KERNEL__ */
+
+#define EFSBADCRC	EBADMSG		/* Bad CRC detected */
+#define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */
+
+#endif	/* _EXT4_H */
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
new file mode 100644
index 000000000..44e59881a
--- /dev/null
+++ b/fs/ext4/ext4_extents.h
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
+ * Written by Alex Tomas <alex@clusterfs.com>
+ */
+
+#ifndef _EXT4_EXTENTS
+#define _EXT4_EXTENTS
+
+#include "ext4.h"
+
+/*
+ * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
+ * becomes very small, so index split, in-depth growing and
+ * other hard changes happen much more often.
+ * This is for debug purposes only.
+ */
+#define AGGRESSIVE_TEST_
+
+/*
+ * With EXTENTS_STATS defined, the number of blocks and extents
+ * are collected in the truncate path. They'll be shown at
+ * umount time.
+ */
+#define EXTENTS_STATS__
+
+/*
+ * If CHECK_BINSEARCH is defined, then the results of the binary search
+ * will also be checked by linear search.
+ */
+#define CHECK_BINSEARCH__
+
+/*
+ * If EXT_STATS is defined then stats numbers are collected.
+ * These number will be displayed at umount time.
+ */
+#define EXT_STATS_
+
+
+/*
+ * ext4_inode has i_block array (60 bytes total).
+ * The first 12 bytes store ext4_extent_header;
+ * the remainder stores an array of ext4_extent.
+ * For non-inode extent blocks, ext4_extent_tail
+ * follows the array.
+ */
+
+/*
+ * This is the extent tail on-disk structure.
+ * All other extent structures are 12 bytes long.  It turns out that
+ * block_size % 12 >= 4 for at least all powers of 2 greater than 512, which
+ * covers all valid ext4 block sizes.  Therefore, this tail structure can be
+ * crammed into the end of the block without having to rebalance the tree.
+ */
+struct ext4_extent_tail {
+	__le32	et_checksum;	/* crc32c(uuid+inum+extent_block) */
+};
+
+/*
+ * This is the extent on-disk structure.
+ * It's used at the bottom of the tree.
+ */
+struct ext4_extent {
+	__le32	ee_block;	/* first logical block extent covers */
+	__le16	ee_len;		/* number of blocks covered by extent */
+	__le16	ee_start_hi;	/* high 16 bits of physical block */
+	__le32	ee_start_lo;	/* low 32 bits of physical block */
+};
+
+/*
+ * This is index on-disk structure.
+ * It's used at all the levels except the bottom.
+ */
+struct ext4_extent_idx {
+	__le32	ei_block;	/* index covers logical blocks from 'block' */
+	__le32	ei_leaf_lo;	/* pointer to the physical block of the next *
+				 * level. leaf or next index could be there */
+	__le16	ei_leaf_hi;	/* high 16 bits of physical block */
+	__u16	ei_unused;
+};
+
+/*
+ * Each block (leaves and indexes), even inode-stored has header.
+ */
+struct ext4_extent_header {
+	__le16	eh_magic;	/* probably will support different formats */
+	__le16	eh_entries;	/* number of valid entries */
+	__le16	eh_max;		/* capacity of store in entries */
+	__le16	eh_depth;	/* has tree real underlying blocks? */
+	__le32	eh_generation;	/* generation of the tree */
+};
+
+#define EXT4_EXT_MAGIC		cpu_to_le16(0xf30a)
+#define EXT4_MAX_EXTENT_DEPTH 5
+
+#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
+	(sizeof(struct ext4_extent_header) + \
+	 (sizeof(struct ext4_extent) * le16_to_cpu((hdr)->eh_max)))
+
+static inline struct ext4_extent_tail *
+find_ext4_extent_tail(struct ext4_extent_header *eh)
+{
+	return (struct ext4_extent_tail *)(((void *)eh) +
+					   EXT4_EXTENT_TAIL_OFFSET(eh));
+}
+
+/*
+ * Array of ext4_ext_path contains path to some extent.
+ * Creation/lookup routines use it for traversal/splitting/etc.
+ * Truncate uses it to simulate recursive walking.
+ */
+struct ext4_ext_path {
+	ext4_fsblk_t			p_block;
+	__u16				p_depth;
+	__u16				p_maxdepth;
+	struct ext4_extent		*p_ext;
+	struct ext4_extent_idx		*p_idx;
+	struct ext4_extent_header	*p_hdr;
+	struct buffer_head		*p_bh;
+};
+
+/*
+ * Used to record a portion of a cluster found at the beginning or end
+ * of an extent while traversing the extent tree during space removal.
+ * A partial cluster may be removed if it does not contain blocks shared
+ * with extents that aren't being deleted (tofree state).  Otherwise,
+ * it cannot be removed (nofree state).
+ */
+struct partial_cluster {
+	ext4_fsblk_t pclu;  /* physical cluster number */
+	ext4_lblk_t lblk;   /* logical block number within logical cluster */
+	enum {initial, tofree, nofree} state;
+};
+
+/*
+ * structure for external API
+ */
+
+/*
+ * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
+ * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
+ * MSB of ee_len field in the extent datastructure to signify if this
+ * particular extent is an initialized extent or an unwritten (i.e.
+ * preallocated).
+ * EXT_UNWRITTEN_MAX_LEN is the maximum number of blocks we can have in an
+ * unwritten extent.
+ * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
+ * unwritten one. In other words, if MSB of ee_len is set, it is an
+ * unwritten extent with only one special scenario when ee_len = 0x8000.
+ * In this case we can not have an unwritten extent of zero length and
+ * thus we make it as a special case of initialized extent with 0x8000 length.
+ * This way we get better extent-to-group alignment for initialized extents.
+ * Hence, the maximum number of blocks we can have in an *initialized*
+ * extent is 2^15 (32768) and in an *unwritten* extent is 2^15-1 (32767).
+ */
+#define EXT_INIT_MAX_LEN	(1UL << 15)
+#define EXT_UNWRITTEN_MAX_LEN	(EXT_INIT_MAX_LEN - 1)
+
+
+#define EXT_FIRST_EXTENT(__hdr__) \
+	((struct ext4_extent *) (((char *) (__hdr__)) +		\
+				 sizeof(struct ext4_extent_header)))
+#define EXT_FIRST_INDEX(__hdr__) \
+	((struct ext4_extent_idx *) (((char *) (__hdr__)) +	\
+				     sizeof(struct ext4_extent_header)))
+#define EXT_HAS_FREE_INDEX(__path__) \
+	(le16_to_cpu((__path__)->p_hdr->eh_entries) \
+				     < le16_to_cpu((__path__)->p_hdr->eh_max))
+#define EXT_LAST_EXTENT(__hdr__) \
+	(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
+#define EXT_LAST_INDEX(__hdr__) \
+	(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
+#define EXT_MAX_EXTENT(__hdr__)	\
+	((le16_to_cpu((__hdr__)->eh_max)) ? \
+	((EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)) \
+					: 0)
+#define EXT_MAX_INDEX(__hdr__) \
+	((le16_to_cpu((__hdr__)->eh_max)) ? \
+	((EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)) : 0)
+
+static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
+{
+	return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
+}
+
+static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
+{
+	return (struct ext4_extent_header *) bh->b_data;
+}
+
+static inline unsigned short ext_depth(struct inode *inode)
+{
+	return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
+}
+
+static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext)
+{
+	/* We can not have an unwritten extent of zero length! */
+	BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
+	ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
+}
+
+static inline int ext4_ext_is_unwritten(struct ext4_extent *ext)
+{
+	/* Extent with ee_len of 0x8000 is treated as an initialized extent */
+	return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
+}
+
+static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
+{
+	return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
+		le16_to_cpu(ext->ee_len) :
+		(le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
+}
+
+static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
+{
+	ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
+}
+
+/*
+ * ext4_ext_pblock:
+ * combine low and high parts of physical block number into ext4_fsblk_t
+ */
+static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
+{
+	ext4_fsblk_t block;
+
+	block = le32_to_cpu(ex->ee_start_lo);
+	block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
+	return block;
+}
+
+/*
+ * ext4_idx_pblock:
+ * combine low and high parts of a leaf physical block number into ext4_fsblk_t
+ */
+static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
+{
+	ext4_fsblk_t block;
+
+	block = le32_to_cpu(ix->ei_leaf_lo);
+	block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
+	return block;
+}
+
+/*
+ * ext4_ext_store_pblock:
+ * stores a large physical block number into an extent struct,
+ * breaking it into parts
+ */
+static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
+					 ext4_fsblk_t pb)
+{
+	ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+	ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
+				      0xffff);
+}
+
+/*
+ * ext4_idx_store_pblock:
+ * stores a large physical block number into an index struct,
+ * breaking it into parts
+ */
+static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
+					 ext4_fsblk_t pb)
+{
+	ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+	ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
+				     0xffff);
+}
+
+#endif /* _EXT4_EXTENTS */
+
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
new file mode 100644
index 000000000..6ff7b4020
--- /dev/null
+++ b/fs/ext4/ext4_jbd2.c
@@ -0,0 +1,393 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Interface between ext4 and JBD
+ */
+
+#include "ext4_jbd2.h"
+
+#include <trace/events/ext4.h>
+
+int ext4_inode_journal_mode(struct inode *inode)
+{
+	if (EXT4_JOURNAL(inode) == NULL)
+		return EXT4_INODE_WRITEBACK_DATA_MODE;	/* writeback */
+	/* We do not support data journalling with delayed allocation */
+	if (!S_ISREG(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE) ||
+	    test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
+	    (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA) &&
+	    !test_opt(inode->i_sb, DELALLOC))) {
+		/* We do not support data journalling for encrypted data */
+		if (S_ISREG(inode->i_mode) && IS_ENCRYPTED(inode))
+			return EXT4_INODE_ORDERED_DATA_MODE;  /* ordered */
+		return EXT4_INODE_JOURNAL_DATA_MODE;	/* journal data */
+	}
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
+		return EXT4_INODE_ORDERED_DATA_MODE;	/* ordered */
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
+		return EXT4_INODE_WRITEBACK_DATA_MODE;	/* writeback */
+	BUG();
+}
+
+/* Just increment the non-pointer handle value */
+static handle_t *ext4_get_nojournal(void)
+{
+	handle_t *handle = current->journal_info;
+	unsigned long ref_cnt = (unsigned long)handle;
+
+	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
+
+	ref_cnt++;
+	handle = (handle_t *)ref_cnt;
+
+	current->journal_info = handle;
+	return handle;
+}
+
+
+/* Decrement the non-pointer handle value */
+static void ext4_put_nojournal(handle_t *handle)
+{
+	unsigned long ref_cnt = (unsigned long)handle;
+
+	BUG_ON(ref_cnt == 0);
+
+	ref_cnt--;
+	handle = (handle_t *)ref_cnt;
+
+	current->journal_info = handle;
+}
+
+/*
+ * Wrappers for jbd2_journal_start/end.
+ */
+static int ext4_journal_check_start(struct super_block *sb)
+{
+	journal_t *journal;
+
+	might_sleep();
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
+		return -EIO;
+
+	if (sb_rdonly(sb))
+		return -EROFS;
+	WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
+	journal = EXT4_SB(sb)->s_journal;
+	/*
+	 * Special case here: if the journal has aborted behind our
+	 * backs (eg. EIO in the commit thread), then we still need to
+	 * take the FS itself readonly cleanly.
+	 */
+	if (journal && is_journal_aborted(journal)) {
+		ext4_abort(sb, -journal->j_errno, "Detected aborted journal");
+		return -EROFS;
+	}
+	return 0;
+}
+
+handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
+				  int type, int blocks, int rsv_blocks,
+				  int revoke_creds)
+{
+	journal_t *journal;
+	int err;
+
+	trace_ext4_journal_start(sb, blocks, rsv_blocks, revoke_creds,
+				 _RET_IP_);
+	err = ext4_journal_check_start(sb);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	journal = EXT4_SB(sb)->s_journal;
+	if (!journal || (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
+		return ext4_get_nojournal();
+	return jbd2__journal_start(journal, blocks, rsv_blocks, revoke_creds,
+				   GFP_NOFS, type, line);
+}
+
+int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
+{
+	struct super_block *sb;
+	int err;
+	int rc;
+
+	if (!ext4_handle_valid(handle)) {
+		ext4_put_nojournal(handle);
+		return 0;
+	}
+
+	err = handle->h_err;
+	if (!handle->h_transaction) {
+		rc = jbd2_journal_stop(handle);
+		return err ? err : rc;
+	}
+
+	sb = handle->h_transaction->t_journal->j_private;
+	rc = jbd2_journal_stop(handle);
+
+	if (!err)
+		err = rc;
+	if (err)
+		__ext4_std_error(sb, where, line, err);
+	return err;
+}
+
+handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
+					int type)
+{
+	struct super_block *sb;
+	int err;
+
+	if (!ext4_handle_valid(handle))
+		return ext4_get_nojournal();
+
+	sb = handle->h_journal->j_private;
+	trace_ext4_journal_start_reserved(sb,
+				jbd2_handle_buffer_credits(handle), _RET_IP_);
+	err = ext4_journal_check_start(sb);
+	if (err < 0) {
+		jbd2_journal_free_reserved(handle);
+		return ERR_PTR(err);
+	}
+
+	err = jbd2_journal_start_reserved(handle, type, line);
+	if (err < 0)
+		return ERR_PTR(err);
+	return handle;
+}
+
+int __ext4_journal_ensure_credits(handle_t *handle, int check_cred,
+				  int extend_cred, int revoke_cred)
+{
+	if (!ext4_handle_valid(handle))
+		return 0;
+	if (is_handle_aborted(handle))
+		return -EROFS;
+	if (jbd2_handle_buffer_credits(handle) >= check_cred &&
+	    handle->h_revoke_credits >= revoke_cred)
+		return 0;
+	extend_cred = max(0, extend_cred - jbd2_handle_buffer_credits(handle));
+	revoke_cred = max(0, revoke_cred - handle->h_revoke_credits);
+	return ext4_journal_extend(handle, extend_cred, revoke_cred);
+}
+
+static void ext4_journal_abort_handle(const char *caller, unsigned int line,
+				      const char *err_fn,
+				      struct buffer_head *bh,
+				      handle_t *handle, int err)
+{
+	char nbuf[16];
+	const char *errstr = ext4_decode_error(NULL, err, nbuf);
+
+	BUG_ON(!ext4_handle_valid(handle));
+
+	if (bh)
+		BUFFER_TRACE(bh, "abort");
+
+	if (!handle->h_err)
+		handle->h_err = err;
+
+	if (is_handle_aborted(handle))
+		return;
+
+	printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n",
+	       caller, line, errstr, err_fn);
+
+	jbd2_journal_abort_handle(handle);
+}
+
+static void ext4_check_bdev_write_error(struct super_block *sb)
+{
+	struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int err;
+
+	/*
+	 * If the block device has write error flag, it may have failed to
+	 * async write out metadata buffers in the background. In this case,
+	 * we could read old data from disk and write it out again, which
+	 * may lead to on-disk filesystem inconsistency.
+	 */
+	if (errseq_check(&mapping->wb_err, READ_ONCE(sbi->s_bdev_wb_err))) {
+		spin_lock(&sbi->s_bdev_wb_lock);
+		err = errseq_check_and_advance(&mapping->wb_err, &sbi->s_bdev_wb_err);
+		spin_unlock(&sbi->s_bdev_wb_lock);
+		if (err)
+			ext4_error_err(sb, -err,
+				       "Error while async write back metadata");
+	}
+}
+
+int __ext4_journal_get_write_access(const char *where, unsigned int line,
+				    handle_t *handle, struct buffer_head *bh)
+{
+	int err = 0;
+
+	might_sleep();
+
+	if (bh->b_bdev->bd_super)
+		ext4_check_bdev_write_error(bh->b_bdev->bd_super);
+
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_get_write_access(handle, bh);
+		if (err)
+			ext4_journal_abort_handle(where, line, __func__, bh,
+						  handle, err);
+	}
+	return err;
+}
+
+/*
+ * The ext4 forget function must perform a revoke if we are freeing data
+ * which has been journaled.  Metadata (eg. indirect blocks) must be
+ * revoked in all cases.
+ *
+ * "bh" may be NULL: a metadata block may have been freed from memory
+ * but there may still be a record of it in the journal, and that record
+ * still needs to be revoked.
+ *
+ * If the handle isn't valid we're not journaling, but we still need to
+ * call into ext4_journal_revoke() to put the buffer head.
+ */
+int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
+		  int is_metadata, struct inode *inode,
+		  struct buffer_head *bh, ext4_fsblk_t blocknr)
+{
+	int err;
+
+	might_sleep();
+
+	trace_ext4_forget(inode, is_metadata, blocknr);
+	BUFFER_TRACE(bh, "enter");
+
+	jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
+		  "data mode %x\n",
+		  bh, is_metadata, inode->i_mode,
+		  test_opt(inode->i_sb, DATA_FLAGS));
+
+	/* In the no journal case, we can just do a bforget and return */
+	if (!ext4_handle_valid(handle)) {
+		bforget(bh);
+		return 0;
+	}
+
+	/* Never use the revoke function if we are doing full data
+	 * journaling: there is no need to, and a V1 superblock won't
+	 * support it.  Otherwise, only skip the revoke on un-journaled
+	 * data blocks. */
+
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
+	    (!is_metadata && !ext4_should_journal_data(inode))) {
+		if (bh) {
+			BUFFER_TRACE(bh, "call jbd2_journal_forget");
+			err = jbd2_journal_forget(handle, bh);
+			if (err)
+				ext4_journal_abort_handle(where, line, __func__,
+							  bh, handle, err);
+			return err;
+		}
+		return 0;
+	}
+
+	/*
+	 * data!=journal && (is_metadata || should_journal_data(inode))
+	 */
+	BUFFER_TRACE(bh, "call jbd2_journal_revoke");
+	err = jbd2_journal_revoke(handle, blocknr, bh);
+	if (err) {
+		ext4_journal_abort_handle(where, line, __func__,
+					  bh, handle, err);
+		__ext4_abort(inode->i_sb, where, line, -err,
+			   "error %d when attempting revoke", err);
+	}
+	BUFFER_TRACE(bh, "exit");
+	return err;
+}
+
+int __ext4_journal_get_create_access(const char *where, unsigned int line,
+				handle_t *handle, struct buffer_head *bh)
+{
+	int err = 0;
+
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_get_create_access(handle, bh);
+		if (err)
+			ext4_journal_abort_handle(where, line, __func__,
+						  bh, handle, err);
+	}
+	return err;
+}
+
+int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
+				 handle_t *handle, struct inode *inode,
+				 struct buffer_head *bh)
+{
+	int err = 0;
+
+	might_sleep();
+
+	set_buffer_meta(bh);
+	set_buffer_prio(bh);
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_dirty_metadata(handle, bh);
+		/* Errors can only happen due to aborted journal or a nasty bug */
+		if (!is_handle_aborted(handle) && WARN_ON_ONCE(err)) {
+			ext4_journal_abort_handle(where, line, __func__, bh,
+						  handle, err);
+			if (inode == NULL) {
+				pr_err("EXT4: jbd2_journal_dirty_metadata "
+				       "failed: handle type %u started at "
+				       "line %u, credits %u/%u, errcode %d",
+				       handle->h_type,
+				       handle->h_line_no,
+				       handle->h_requested_credits,
+				       jbd2_handle_buffer_credits(handle), err);
+				return err;
+			}
+			ext4_error_inode(inode, where, line,
+					 bh->b_blocknr,
+					 "journal_dirty_metadata failed: "
+					 "handle type %u started at line %u, "
+					 "credits %u/%u, errcode %d",
+					 handle->h_type,
+					 handle->h_line_no,
+					 handle->h_requested_credits,
+					 jbd2_handle_buffer_credits(handle),
+					 err);
+		}
+	} else {
+		set_buffer_uptodate(bh);
+		if (inode)
+			mark_buffer_dirty_inode(bh, inode);
+		else
+			mark_buffer_dirty(bh);
+		if (inode && inode_needs_sync(inode)) {
+			sync_dirty_buffer(bh);
+			if (buffer_req(bh) && !buffer_uptodate(bh)) {
+				ext4_error_inode_err(inode, where, line,
+						     bh->b_blocknr, EIO,
+					"IO error syncing itable block");
+				err = -EIO;
+			}
+		}
+	}
+	return err;
+}
+
+int __ext4_handle_dirty_super(const char *where, unsigned int line,
+			      handle_t *handle, struct super_block *sb)
+{
+	struct buffer_head *bh = EXT4_SB(sb)->s_sbh;
+	int err = 0;
+
+	ext4_superblock_csum_set(sb);
+	if (ext4_handle_valid(handle)) {
+		err = jbd2_journal_dirty_metadata(handle, bh);
+		if (err)
+			ext4_journal_abort_handle(where, line, __func__,
+						  bh, handle, err);
+	} else
+		mark_buffer_dirty(bh);
+	return err;
+}
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
new file mode 100644
index 000000000..00dc668e0
--- /dev/null
+++ b/fs/ext4/ext4_jbd2.h
@@ -0,0 +1,518 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ext4_jbd2.h
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
+ *
+ * Copyright 1998--1999 Red Hat corp --- All Rights Reserved
+ *
+ * Ext4-specific journaling extensions.
+ */
+
+#ifndef _EXT4_JBD2_H
+#define _EXT4_JBD2_H
+
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include "ext4.h"
+
+#define EXT4_JOURNAL(inode)	(EXT4_SB((inode)->i_sb)->s_journal)
+
+/* Define the number of blocks we need to account to a transaction to
+ * modify one block of data.
+ *
+ * We may have to touch one inode, one bitmap buffer, up to three
+ * indirection blocks, the group and superblock summaries, and the data
+ * block to complete the transaction.
+ *
+ * For extents-enabled fs we may have to allocate and modify up to
+ * 5 levels of tree, data block (for each of these we need bitmap + group
+ * summaries), root which is stored in the inode, sb
+ */
+
+#define EXT4_SINGLEDATA_TRANS_BLOCKS(sb)				\
+	(ext4_has_feature_extents(sb) ? 20U : 8U)
+
+/* Extended attribute operations touch at most two data buffers,
+ * two bitmap buffers, and two group summaries, in addition to the inode
+ * and the superblock, which are already accounted for. */
+
+#define EXT4_XATTR_TRANS_BLOCKS		6U
+
+/* Define the minimum size for a transaction which modifies data.  This
+ * needs to take into account the fact that we may end up modifying two
+ * quota files too (one for the group, one for the user quota).  The
+ * superblock only gets updated once, of course, so don't bother
+ * counting that again for the quota updates. */
+
+#define EXT4_DATA_TRANS_BLOCKS(sb)	(EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + \
+					 EXT4_XATTR_TRANS_BLOCKS - 2 + \
+					 EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
+
+/*
+ * Define the number of metadata blocks we need to account to modify data.
+ *
+ * This include super block, inode block, quota blocks and xattr blocks
+ */
+#define EXT4_META_TRANS_BLOCKS(sb)	(EXT4_XATTR_TRANS_BLOCKS + \
+					EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
+
+/* Define an arbitrary limit for the amount of data we will anticipate
+ * writing to any given transaction.  For unbounded transactions such as
+ * write(2) and truncate(2) we can write more than this, but we always
+ * start off at the maximum transaction size and grow the transaction
+ * optimistically as we go. */
+
+#define EXT4_MAX_TRANS_DATA		64U
+
+/* We break up a large truncate or write transaction once the handle's
+ * buffer credits gets this low, we need either to extend the
+ * transaction or to start a new one.  Reserve enough space here for
+ * inode, bitmap, superblock, group and indirection updates for at least
+ * one block, plus two quota updates.  Quota allocations are not
+ * needed. */
+
+#define EXT4_RESERVE_TRANS_BLOCKS	12U
+
+/*
+ * Number of credits needed if we need to insert an entry into a
+ * directory.  For each new index block, we need 4 blocks (old index
+ * block, new index block, bitmap block, bg summary).  For normal
+ * htree directories there are 2 levels; if the largedir feature
+ * enabled it's 3 levels.
+ */
+#define EXT4_INDEX_EXTRA_TRANS_BLOCKS	12U
+
+#ifdef CONFIG_QUOTA
+/* Amount of blocks needed for quota update - we know that the structure was
+ * allocated so we need to update only data block */
+#define EXT4_QUOTA_TRANS_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
+		ext4_has_feature_quota(sb)) ? 1 : 0)
+/* Amount of blocks needed for quota insert/delete - we do some block writes
+ * but inode, sb and group updates are done only once */
+#define EXT4_QUOTA_INIT_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
+		ext4_has_feature_quota(sb)) ?\
+		(DQUOT_INIT_ALLOC*(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)\
+		 +3+DQUOT_INIT_REWRITE) : 0)
+
+#define EXT4_QUOTA_DEL_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
+		ext4_has_feature_quota(sb)) ?\
+		(DQUOT_DEL_ALLOC*(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)\
+		 +3+DQUOT_DEL_REWRITE) : 0)
+#else
+#define EXT4_QUOTA_TRANS_BLOCKS(sb) 0
+#define EXT4_QUOTA_INIT_BLOCKS(sb) 0
+#define EXT4_QUOTA_DEL_BLOCKS(sb) 0
+#endif
+#define EXT4_MAXQUOTAS_TRANS_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_TRANS_BLOCKS(sb))
+#define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
+#define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
+
+/*
+ * Ext4 handle operation types -- for logging purposes
+ */
+#define EXT4_HT_MISC             0
+#define EXT4_HT_INODE            1
+#define EXT4_HT_WRITE_PAGE       2
+#define EXT4_HT_MAP_BLOCKS       3
+#define EXT4_HT_DIR              4
+#define EXT4_HT_TRUNCATE         5
+#define EXT4_HT_QUOTA            6
+#define EXT4_HT_RESIZE           7
+#define EXT4_HT_MIGRATE          8
+#define EXT4_HT_MOVE_EXTENTS     9
+#define EXT4_HT_XATTR           10
+#define EXT4_HT_EXT_CONVERT     11
+#define EXT4_HT_MAX             12
+
+/**
+ *   struct ext4_journal_cb_entry - Base structure for callback information.
+ *
+ *   This struct is a 'seed' structure for a using with your own callback
+ *   structs. If you are using callbacks you must allocate one of these
+ *   or another struct of your own definition which has this struct
+ *   as it's first element and pass it to ext4_journal_callback_add().
+ */
+struct ext4_journal_cb_entry {
+	/* list information for other callbacks attached to the same handle */
+	struct list_head jce_list;
+
+	/*  Function to call with this callback structure */
+	void (*jce_func)(struct super_block *sb,
+			 struct ext4_journal_cb_entry *jce, int error);
+
+	/* user data goes here */
+};
+
+/**
+ * ext4_journal_callback_add: add a function to call after transaction commit
+ * @handle: active journal transaction handle to register callback on
+ * @func: callback function to call after the transaction has committed:
+ *        @sb: superblock of current filesystem for transaction
+ *        @jce: returned journal callback data
+ *        @rc: journal state at commit (0 = transaction committed properly)
+ * @jce: journal callback data (internal and function private data struct)
+ *
+ * The registered function will be called in the context of the journal thread
+ * after the transaction for which the handle was created has completed.
+ *
+ * No locks are held when the callback function is called, so it is safe to
+ * call blocking functions from within the callback, but the callback should
+ * not block or run for too long, or the filesystem will be blocked waiting for
+ * the next transaction to commit. No journaling functions can be used, or
+ * there is a risk of deadlock.
+ *
+ * There is no guaranteed calling order of multiple registered callbacks on
+ * the same transaction.
+ */
+static inline void _ext4_journal_callback_add(handle_t *handle,
+			struct ext4_journal_cb_entry *jce)
+{
+	/* Add the jce to transaction's private list */
+	list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);
+}
+
+static inline void ext4_journal_callback_add(handle_t *handle,
+			void (*func)(struct super_block *sb,
+				     struct ext4_journal_cb_entry *jce,
+				     int rc),
+			struct ext4_journal_cb_entry *jce)
+{
+	struct ext4_sb_info *sbi =
+			EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+	/* Add the jce to transaction's private list */
+	jce->jce_func = func;
+	spin_lock(&sbi->s_md_lock);
+	_ext4_journal_callback_add(handle, jce);
+	spin_unlock(&sbi->s_md_lock);
+}
+
+
+/**
+ * ext4_journal_callback_del: delete a registered callback
+ * @handle: active journal transaction handle on which callback was registered
+ * @jce: registered journal callback entry to unregister
+ * Return true if object was successfully removed
+ */
+static inline bool ext4_journal_callback_try_del(handle_t *handle,
+					     struct ext4_journal_cb_entry *jce)
+{
+	bool deleted;
+	struct ext4_sb_info *sbi =
+			EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+	spin_lock(&sbi->s_md_lock);
+	deleted = !list_empty(&jce->jce_list);
+	list_del_init(&jce->jce_list);
+	spin_unlock(&sbi->s_md_lock);
+	return deleted;
+}
+
+int
+ext4_mark_iloc_dirty(handle_t *handle,
+		     struct inode *inode,
+		     struct ext4_iloc *iloc);
+
+/*
+ * On success, We end up with an outstanding reference count against
+ * iloc->bh.  This _must_ be cleaned up later.
+ */
+
+int ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
+			struct ext4_iloc *iloc);
+
+#define ext4_mark_inode_dirty(__h, __i)					\
+		__ext4_mark_inode_dirty((__h), (__i), __func__, __LINE__)
+int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
+				const char *func, unsigned int line);
+
+int ext4_expand_extra_isize(struct inode *inode,
+			    unsigned int new_extra_isize,
+			    struct ext4_iloc *iloc);
+/*
+ * Wrapper functions with which ext4 calls into JBD.
+ */
+int __ext4_journal_get_write_access(const char *where, unsigned int line,
+				    handle_t *handle, struct buffer_head *bh);
+
+int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
+		  int is_metadata, struct inode *inode,
+		  struct buffer_head *bh, ext4_fsblk_t blocknr);
+
+int __ext4_journal_get_create_access(const char *where, unsigned int line,
+				handle_t *handle, struct buffer_head *bh);
+
+int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
+				 handle_t *handle, struct inode *inode,
+				 struct buffer_head *bh);
+
+int __ext4_handle_dirty_super(const char *where, unsigned int line,
+			      handle_t *handle, struct super_block *sb);
+
+#define ext4_journal_get_write_access(handle, bh) \
+	__ext4_journal_get_write_access(__func__, __LINE__, (handle), (bh))
+#define ext4_forget(handle, is_metadata, inode, bh, block_nr) \
+	__ext4_forget(__func__, __LINE__, (handle), (is_metadata), (inode), \
+		      (bh), (block_nr))
+#define ext4_journal_get_create_access(handle, bh) \
+	__ext4_journal_get_create_access(__func__, __LINE__, (handle), (bh))
+#define ext4_handle_dirty_metadata(handle, inode, bh) \
+	__ext4_handle_dirty_metadata(__func__, __LINE__, (handle), (inode), \
+				     (bh))
+#define ext4_handle_dirty_super(handle, sb) \
+	__ext4_handle_dirty_super(__func__, __LINE__, (handle), (sb))
+
+handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
+				  int type, int blocks, int rsv_blocks,
+				  int revoke_creds);
+int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle);
+
+#define EXT4_NOJOURNAL_MAX_REF_COUNT ((unsigned long) 4096)
+
+/* Note:  Do not use this for NULL handles.  This is only to determine if
+ * a properly allocated handle is using a journal or not. */
+static inline int ext4_handle_valid(handle_t *handle)
+{
+	if ((unsigned long)handle < EXT4_NOJOURNAL_MAX_REF_COUNT)
+		return 0;
+	return 1;
+}
+
+static inline void ext4_handle_sync(handle_t *handle)
+{
+	if (ext4_handle_valid(handle))
+		handle->h_sync = 1;
+}
+
+static inline int ext4_handle_is_aborted(handle_t *handle)
+{
+	if (ext4_handle_valid(handle))
+		return is_handle_aborted(handle);
+	return 0;
+}
+
+static inline int ext4_free_metadata_revoke_credits(struct super_block *sb,
+						    int blocks)
+{
+	/* Freeing each metadata block can result in freeing one cluster */
+	return blocks * EXT4_SB(sb)->s_cluster_ratio;
+}
+
+static inline int ext4_trans_default_revoke_credits(struct super_block *sb)
+{
+	return ext4_free_metadata_revoke_credits(sb, 8);
+}
+
+#define ext4_journal_start_sb(sb, type, nblocks)			\
+	__ext4_journal_start_sb((sb), __LINE__, (type), (nblocks), 0,	\
+				ext4_trans_default_revoke_credits(sb))
+
+#define ext4_journal_start(inode, type, nblocks)			\
+	__ext4_journal_start((inode), __LINE__, (type), (nblocks), 0,	\
+			     ext4_trans_default_revoke_credits((inode)->i_sb))
+
+#define ext4_journal_start_with_reserve(inode, type, blocks, rsv_blocks)\
+	__ext4_journal_start((inode), __LINE__, (type), (blocks), (rsv_blocks),\
+			     ext4_trans_default_revoke_credits((inode)->i_sb))
+
+#define ext4_journal_start_with_revoke(inode, type, blocks, revoke_creds) \
+	__ext4_journal_start((inode), __LINE__, (type), (blocks), 0,	\
+			     (revoke_creds))
+
+static inline handle_t *__ext4_journal_start(struct inode *inode,
+					     unsigned int line, int type,
+					     int blocks, int rsv_blocks,
+					     int revoke_creds)
+{
+	return __ext4_journal_start_sb(inode->i_sb, line, type, blocks,
+				       rsv_blocks, revoke_creds);
+}
+
+#define ext4_journal_stop(handle) \
+	__ext4_journal_stop(__func__, __LINE__, (handle))
+
+#define ext4_journal_start_reserved(handle, type) \
+	__ext4_journal_start_reserved((handle), __LINE__, (type))
+
+handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
+					int type);
+
+static inline handle_t *ext4_journal_current_handle(void)
+{
+	return journal_current_handle();
+}
+
+static inline int ext4_journal_extend(handle_t *handle, int nblocks, int revoke)
+{
+	if (ext4_handle_valid(handle))
+		return jbd2_journal_extend(handle, nblocks, revoke);
+	return 0;
+}
+
+static inline int ext4_journal_restart(handle_t *handle, int nblocks,
+				       int revoke)
+{
+	if (ext4_handle_valid(handle))
+		return jbd2__journal_restart(handle, nblocks, revoke, GFP_NOFS);
+	return 0;
+}
+
+int __ext4_journal_ensure_credits(handle_t *handle, int check_cred,
+				  int extend_cred, int revoke_cred);
+
+
+/*
+ * Ensure @handle has at least @check_creds credits available. If not,
+ * transaction will be extended or restarted to contain at least @extend_cred
+ * credits. Before restarting transaction @fn is executed to allow for cleanup
+ * before the transaction is restarted.
+ *
+ * The return value is < 0 in case of error, 0 in case the handle has enough
+ * credits or transaction extension succeeded, 1 in case transaction had to be
+ * restarted.
+ */
+#define ext4_journal_ensure_credits_fn(handle, check_cred, extend_cred,	\
+				       revoke_cred, fn) \
+({									\
+	__label__ __ensure_end;						\
+	int err = __ext4_journal_ensure_credits((handle), (check_cred),	\
+					(extend_cred), (revoke_cred));	\
+									\
+	if (err <= 0)							\
+		goto __ensure_end;					\
+	err = (fn);							\
+	if (err < 0)							\
+		goto __ensure_end;					\
+	err = ext4_journal_restart((handle), (extend_cred), (revoke_cred)); \
+	if (err == 0)							\
+		err = 1;						\
+__ensure_end:								\
+	err;								\
+})
+
+/*
+ * Ensure given handle has at least requested amount of credits available,
+ * possibly restarting transaction if needed. We also make sure the transaction
+ * has space for at least ext4_trans_default_revoke_credits(sb) revoke records
+ * as freeing one or two blocks is very common pattern and requesting this is
+ * very cheap.
+ */
+static inline int ext4_journal_ensure_credits(handle_t *handle, int credits,
+					      int revoke_creds)
+{
+	return ext4_journal_ensure_credits_fn(handle, credits, credits,
+				revoke_creds, 0);
+}
+
+static inline int ext4_journal_blocks_per_page(struct inode *inode)
+{
+	if (EXT4_JOURNAL(inode) != NULL)
+		return jbd2_journal_blocks_per_page(inode);
+	return 0;
+}
+
+static inline int ext4_journal_force_commit(journal_t *journal)
+{
+	if (journal)
+		return jbd2_journal_force_commit(journal);
+	return 0;
+}
+
+static inline int ext4_jbd2_inode_add_write(handle_t *handle,
+		struct inode *inode, loff_t start_byte, loff_t length)
+{
+	if (ext4_handle_valid(handle))
+		return jbd2_journal_inode_ranged_write(handle,
+				EXT4_I(inode)->jinode, start_byte, length);
+	return 0;
+}
+
+static inline int ext4_jbd2_inode_add_wait(handle_t *handle,
+		struct inode *inode, loff_t start_byte, loff_t length)
+{
+	if (ext4_handle_valid(handle))
+		return jbd2_journal_inode_ranged_wait(handle,
+				EXT4_I(inode)->jinode, start_byte, length);
+	return 0;
+}
+
+static inline void ext4_update_inode_fsync_trans(handle_t *handle,
+						 struct inode *inode,
+						 int datasync)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (ext4_handle_valid(handle) && !is_handle_aborted(handle)) {
+		ei->i_sync_tid = handle->h_transaction->t_tid;
+		if (datasync)
+			ei->i_datasync_tid = handle->h_transaction->t_tid;
+	}
+}
+
+/* super.c */
+int ext4_force_commit(struct super_block *sb);
+
+/*
+ * Ext4 inode journal modes
+ */
+#define EXT4_INODE_JOURNAL_DATA_MODE	0x01 /* journal data mode */
+#define EXT4_INODE_ORDERED_DATA_MODE	0x02 /* ordered data mode */
+#define EXT4_INODE_WRITEBACK_DATA_MODE	0x04 /* writeback data mode */
+
+int ext4_inode_journal_mode(struct inode *inode);
+
+static inline int ext4_should_journal_data(struct inode *inode)
+{
+	return ext4_inode_journal_mode(inode) & EXT4_INODE_JOURNAL_DATA_MODE;
+}
+
+static inline int ext4_should_order_data(struct inode *inode)
+{
+	return ext4_inode_journal_mode(inode) & EXT4_INODE_ORDERED_DATA_MODE;
+}
+
+static inline int ext4_should_writeback_data(struct inode *inode)
+{
+	return ext4_inode_journal_mode(inode) & EXT4_INODE_WRITEBACK_DATA_MODE;
+}
+
+static inline int ext4_free_data_revoke_credits(struct inode *inode, int blocks)
+{
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
+		return 0;
+	if (!ext4_should_journal_data(inode))
+		return 0;
+	/*
+	 * Data blocks in one extent are contiguous, just account for partial
+	 * clusters at extent boundaries
+	 */
+	return blocks + 2*(EXT4_SB(inode->i_sb)->s_cluster_ratio - 1);
+}
+
+/*
+ * This function controls whether or not we should try to go down the
+ * dioread_nolock code paths, which makes it safe to avoid taking
+ * i_mutex for direct I/O reads.  This only works for extent-based
+ * files, and it doesn't work if data journaling is enabled, since the
+ * dioread_nolock code uses b_private to pass information back to the
+ * I/O completion handler, and this conflicts with the jbd's use of
+ * b_private.
+ */
+static inline int ext4_should_dioread_nolock(struct inode *inode)
+{
+	if (!test_opt(inode->i_sb, DIOREAD_NOLOCK))
+		return 0;
+	if (!S_ISREG(inode->i_mode))
+		return 0;
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		return 0;
+	if (ext4_should_journal_data(inode))
+		return 0;
+	/* temporary fix to prevent generic/422 test failures */
+	if (!test_opt(inode->i_sb, DELALLOC))
+		return 0;
+	return 1;
+}
+
+#endif	/* _EXT4_JBD2_H */
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
new file mode 100644
index 000000000..193b13630
--- /dev/null
+++ b/fs/ext4/extents.c
@@ -0,0 +1,6143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
+ * Written by Alex Tomas <alex@clusterfs.com>
+ *
+ * Architecture independence:
+ *   Copyright (c) 2005, Bull S.A.
+ *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
+ */
+
+/*
+ * Extents support for EXT4
+ *
+ * TODO:
+ *   - ext4*_error() should be used in some situations
+ *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
+ *   - smart tree reduction
+ */
+
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/jbd2.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/fiemap.h>
+#include <linux/backing-dev.h>
+#include <linux/iomap.h>
+#include "ext4_jbd2.h"
+#include "ext4_extents.h"
+#include "xattr.h"
+
+#include <trace/events/ext4.h>
+
+/*
+ * used by extent splitting.
+ */
+#define EXT4_EXT_MAY_ZEROOUT	0x1  /* safe to zeroout if split fails \
+					due to ENOSPC */
+#define EXT4_EXT_MARK_UNWRIT1	0x2  /* mark first half unwritten */
+#define EXT4_EXT_MARK_UNWRIT2	0x4  /* mark second half unwritten */
+
+#define EXT4_EXT_DATA_VALID1	0x8  /* first half contains valid data */
+#define EXT4_EXT_DATA_VALID2	0x10 /* second half contains valid data */
+
+static __le32 ext4_extent_block_csum(struct inode *inode,
+				     struct ext4_extent_header *eh)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	__u32 csum;
+
+	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
+			   EXT4_EXTENT_TAIL_OFFSET(eh));
+	return cpu_to_le32(csum);
+}
+
+static int ext4_extent_block_csum_verify(struct inode *inode,
+					 struct ext4_extent_header *eh)
+{
+	struct ext4_extent_tail *et;
+
+	if (!ext4_has_metadata_csum(inode->i_sb))
+		return 1;
+
+	et = find_ext4_extent_tail(eh);
+	if (et->et_checksum != ext4_extent_block_csum(inode, eh))
+		return 0;
+	return 1;
+}
+
+static void ext4_extent_block_csum_set(struct inode *inode,
+				       struct ext4_extent_header *eh)
+{
+	struct ext4_extent_tail *et;
+
+	if (!ext4_has_metadata_csum(inode->i_sb))
+		return;
+
+	et = find_ext4_extent_tail(eh);
+	et->et_checksum = ext4_extent_block_csum(inode, eh);
+}
+
+static int ext4_split_extent_at(handle_t *handle,
+			     struct inode *inode,
+			     struct ext4_ext_path **ppath,
+			     ext4_lblk_t split,
+			     int split_flag,
+			     int flags);
+
+static int ext4_ext_trunc_restart_fn(struct inode *inode, int *dropped)
+{
+	/*
+	 * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
+	 * moment, get_block can be called only for blocks inside i_size since
+	 * page cache has been already dropped and writes are blocked by
+	 * i_mutex. So we can safely drop the i_data_sem here.
+	 */
+	BUG_ON(EXT4_JOURNAL(inode) == NULL);
+	ext4_discard_preallocations(inode, 0);
+	up_write(&EXT4_I(inode)->i_data_sem);
+	*dropped = 1;
+	return 0;
+}
+
+/*
+ * Make sure 'handle' has at least 'check_cred' credits. If not, restart
+ * transaction with 'restart_cred' credits. The function drops i_data_sem
+ * when restarting transaction and gets it after transaction is restarted.
+ *
+ * The function returns 0 on success, 1 if transaction had to be restarted,
+ * and < 0 in case of fatal error.
+ */
+int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
+				int check_cred, int restart_cred,
+				int revoke_cred)
+{
+	int ret;
+	int dropped = 0;
+
+	ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,
+		revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));
+	if (dropped)
+		down_write(&EXT4_I(inode)->i_data_sem);
+	return ret;
+}
+
+/*
+ * could return:
+ *  - EROFS
+ *  - ENOMEM
+ */
+static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
+				struct ext4_ext_path *path)
+{
+	int err = 0;
+
+	if (path->p_bh) {
+		/* path points to block */
+		BUFFER_TRACE(path->p_bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, path->p_bh);
+		/*
+		 * The extent buffer's verified bit will be set again in
+		 * __ext4_ext_dirty(). We could leave an inconsistent
+		 * buffer if the extents updating procudure break off du
+		 * to some error happens, force to check it again.
+		 */
+		if (!err)
+			clear_buffer_verified(path->p_bh);
+	}
+	/* path points to leaf/index in inode body */
+	/* we use in-core data, no need to protect them */
+	return err;
+}
+
+/*
+ * could return:
+ *  - EROFS
+ *  - ENOMEM
+ *  - EIO
+ */
+static int __ext4_ext_dirty(const char *where, unsigned int line,
+			    handle_t *handle, struct inode *inode,
+			    struct ext4_ext_path *path)
+{
+	int err;
+
+	WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
+	if (path->p_bh) {
+		ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
+		/* path points to block */
+		err = __ext4_handle_dirty_metadata(where, line, handle,
+						   inode, path->p_bh);
+		/* Extents updating done, re-set verified flag */
+		if (!err)
+			set_buffer_verified(path->p_bh);
+	} else {
+		/* path points to leaf/index in inode body */
+		err = ext4_mark_inode_dirty(handle, inode);
+	}
+	return err;
+}
+
+#define ext4_ext_dirty(handle, inode, path) \
+		__ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
+
+static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
+			      struct ext4_ext_path *path,
+			      ext4_lblk_t block)
+{
+	if (path) {
+		int depth = path->p_depth;
+		struct ext4_extent *ex;
+
+		/*
+		 * Try to predict block placement assuming that we are
+		 * filling in a file which will eventually be
+		 * non-sparse --- i.e., in the case of libbfd writing
+		 * an ELF object sections out-of-order but in a way
+		 * the eventually results in a contiguous object or
+		 * executable file, or some database extending a table
+		 * space file.  However, this is actually somewhat
+		 * non-ideal if we are writing a sparse file such as
+		 * qemu or KVM writing a raw image file that is going
+		 * to stay fairly sparse, since it will end up
+		 * fragmenting the file system's free space.  Maybe we
+		 * should have some hueristics or some way to allow
+		 * userspace to pass a hint to file system,
+		 * especially if the latter case turns out to be
+		 * common.
+		 */
+		ex = path[depth].p_ext;
+		if (ex) {
+			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
+			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
+
+			if (block > ext_block)
+				return ext_pblk + (block - ext_block);
+			else
+				return ext_pblk - (ext_block - block);
+		}
+
+		/* it looks like index is empty;
+		 * try to find starting block from index itself */
+		if (path[depth].p_bh)
+			return path[depth].p_bh->b_blocknr;
+	}
+
+	/* OK. use inode's group */
+	return ext4_inode_to_goal_block(inode);
+}
+
+/*
+ * Allocation for a meta data block
+ */
+static ext4_fsblk_t
+ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
+			struct ext4_ext_path *path,
+			struct ext4_extent *ex, int *err, unsigned int flags)
+{
+	ext4_fsblk_t goal, newblock;
+
+	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
+	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
+					NULL, err);
+	return newblock;
+}
+
+static inline int ext4_ext_space_block(struct inode *inode, int check)
+{
+	int size;
+
+	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
+			/ sizeof(struct ext4_extent);
+#ifdef AGGRESSIVE_TEST
+	if (!check && size > 6)
+		size = 6;
+#endif
+	return size;
+}
+
+static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
+{
+	int size;
+
+	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
+			/ sizeof(struct ext4_extent_idx);
+#ifdef AGGRESSIVE_TEST
+	if (!check && size > 5)
+		size = 5;
+#endif
+	return size;
+}
+
+static inline int ext4_ext_space_root(struct inode *inode, int check)
+{
+	int size;
+
+	size = sizeof(EXT4_I(inode)->i_data);
+	size -= sizeof(struct ext4_extent_header);
+	size /= sizeof(struct ext4_extent);
+#ifdef AGGRESSIVE_TEST
+	if (!check && size > 3)
+		size = 3;
+#endif
+	return size;
+}
+
+static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
+{
+	int size;
+
+	size = sizeof(EXT4_I(inode)->i_data);
+	size -= sizeof(struct ext4_extent_header);
+	size /= sizeof(struct ext4_extent_idx);
+#ifdef AGGRESSIVE_TEST
+	if (!check && size > 4)
+		size = 4;
+#endif
+	return size;
+}
+
+static inline int
+ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
+			   struct ext4_ext_path **ppath, ext4_lblk_t lblk,
+			   int nofail)
+{
+	struct ext4_ext_path *path = *ppath;
+	int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
+	int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
+
+	if (nofail)
+		flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
+
+	return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
+			EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
+			flags);
+}
+
+static int
+ext4_ext_max_entries(struct inode *inode, int depth)
+{
+	int max;
+
+	if (depth == ext_depth(inode)) {
+		if (depth == 0)
+			max = ext4_ext_space_root(inode, 1);
+		else
+			max = ext4_ext_space_root_idx(inode, 1);
+	} else {
+		if (depth == 0)
+			max = ext4_ext_space_block(inode, 1);
+		else
+			max = ext4_ext_space_block_idx(inode, 1);
+	}
+
+	return max;
+}
+
+static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
+{
+	ext4_fsblk_t block = ext4_ext_pblock(ext);
+	int len = ext4_ext_get_actual_len(ext);
+	ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
+
+	/*
+	 * We allow neither:
+	 *  - zero length
+	 *  - overflow/wrap-around
+	 */
+	if (lblock + len <= lblock)
+		return 0;
+	return ext4_inode_block_valid(inode, block, len);
+}
+
+static int ext4_valid_extent_idx(struct inode *inode,
+				struct ext4_extent_idx *ext_idx)
+{
+	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
+
+	return ext4_inode_block_valid(inode, block, 1);
+}
+
+static int ext4_valid_extent_entries(struct inode *inode,
+				     struct ext4_extent_header *eh,
+				     ext4_lblk_t lblk, ext4_fsblk_t *pblk,
+				     int depth)
+{
+	unsigned short entries;
+	ext4_lblk_t lblock = 0;
+	ext4_lblk_t cur = 0;
+
+	if (eh->eh_entries == 0)
+		return 1;
+
+	entries = le16_to_cpu(eh->eh_entries);
+
+	if (depth == 0) {
+		/* leaf entries */
+		struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
+
+		/*
+		 * The logical block in the first entry should equal to
+		 * the number in the index block.
+		 */
+		if (depth != ext_depth(inode) &&
+		    lblk != le32_to_cpu(ext->ee_block))
+			return 0;
+		while (entries) {
+			if (!ext4_valid_extent(inode, ext))
+				return 0;
+
+			/* Check for overlapping extents */
+			lblock = le32_to_cpu(ext->ee_block);
+			if (lblock < cur) {
+				*pblk = ext4_ext_pblock(ext);
+				return 0;
+			}
+			cur = lblock + ext4_ext_get_actual_len(ext);
+			ext++;
+			entries--;
+		}
+	} else {
+		struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
+
+		/*
+		 * The logical block in the first entry should equal to
+		 * the number in the parent index block.
+		 */
+		if (depth != ext_depth(inode) &&
+		    lblk != le32_to_cpu(ext_idx->ei_block))
+			return 0;
+		while (entries) {
+			if (!ext4_valid_extent_idx(inode, ext_idx))
+				return 0;
+
+			/* Check for overlapping index extents */
+			lblock = le32_to_cpu(ext_idx->ei_block);
+			if (lblock < cur) {
+				*pblk = ext4_idx_pblock(ext_idx);
+				return 0;
+			}
+			ext_idx++;
+			entries--;
+			cur = lblock + 1;
+		}
+	}
+	return 1;
+}
+
+static int __ext4_ext_check(const char *function, unsigned int line,
+			    struct inode *inode, struct ext4_extent_header *eh,
+			    int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
+{
+	const char *error_msg;
+	int max = 0, err = -EFSCORRUPTED;
+
+	if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
+		error_msg = "invalid magic";
+		goto corrupted;
+	}
+	if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
+		error_msg = "unexpected eh_depth";
+		goto corrupted;
+	}
+	if (unlikely(eh->eh_max == 0)) {
+		error_msg = "invalid eh_max";
+		goto corrupted;
+	}
+	max = ext4_ext_max_entries(inode, depth);
+	if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
+		error_msg = "too large eh_max";
+		goto corrupted;
+	}
+	if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
+		error_msg = "invalid eh_entries";
+		goto corrupted;
+	}
+	if (unlikely((eh->eh_entries == 0) && (depth > 0))) {
+		error_msg = "eh_entries is 0 but eh_depth is > 0";
+		goto corrupted;
+	}
+	if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
+		error_msg = "invalid extent entries";
+		goto corrupted;
+	}
+	if (unlikely(depth > 32)) {
+		error_msg = "too large eh_depth";
+		goto corrupted;
+	}
+	/* Verify checksum on non-root extent tree nodes */
+	if (ext_depth(inode) != depth &&
+	    !ext4_extent_block_csum_verify(inode, eh)) {
+		error_msg = "extent tree corrupted";
+		err = -EFSBADCRC;
+		goto corrupted;
+	}
+	return 0;
+
+corrupted:
+	ext4_error_inode_err(inode, function, line, 0, -err,
+			     "pblk %llu bad header/extent: %s - magic %x, "
+			     "entries %u, max %u(%u), depth %u(%u)",
+			     (unsigned long long) pblk, error_msg,
+			     le16_to_cpu(eh->eh_magic),
+			     le16_to_cpu(eh->eh_entries),
+			     le16_to_cpu(eh->eh_max),
+			     max, le16_to_cpu(eh->eh_depth), depth);
+	return err;
+}
+
+#define ext4_ext_check(inode, eh, depth, pblk)			\
+	__ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
+
+int ext4_ext_check_inode(struct inode *inode)
+{
+	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
+}
+
+static void ext4_cache_extents(struct inode *inode,
+			       struct ext4_extent_header *eh)
+{
+	struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
+	ext4_lblk_t prev = 0;
+	int i;
+
+	for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
+		unsigned int status = EXTENT_STATUS_WRITTEN;
+		ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
+		int len = ext4_ext_get_actual_len(ex);
+
+		if (prev && (prev != lblk))
+			ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
+					     EXTENT_STATUS_HOLE);
+
+		if (ext4_ext_is_unwritten(ex))
+			status = EXTENT_STATUS_UNWRITTEN;
+		ext4_es_cache_extent(inode, lblk, len,
+				     ext4_ext_pblock(ex), status);
+		prev = lblk + len;
+	}
+}
+
+static struct buffer_head *
+__read_extent_tree_block(const char *function, unsigned int line,
+			 struct inode *inode, struct ext4_extent_idx *idx,
+			 int depth, int flags)
+{
+	struct buffer_head		*bh;
+	int				err;
+	gfp_t				gfp_flags = __GFP_MOVABLE | GFP_NOFS;
+	ext4_fsblk_t			pblk;
+
+	if (flags & EXT4_EX_NOFAIL)
+		gfp_flags |= __GFP_NOFAIL;
+
+	pblk = ext4_idx_pblock(idx);
+	bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
+	if (unlikely(!bh))
+		return ERR_PTR(-ENOMEM);
+
+	if (!bh_uptodate_or_lock(bh)) {
+		trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
+		err = ext4_read_bh(bh, 0, NULL);
+		if (err < 0)
+			goto errout;
+	}
+	if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
+		return bh;
+	err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
+			       depth, pblk, le32_to_cpu(idx->ei_block));
+	if (err)
+		goto errout;
+	set_buffer_verified(bh);
+	/*
+	 * If this is a leaf block, cache all of its entries
+	 */
+	if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
+		struct ext4_extent_header *eh = ext_block_hdr(bh);
+		ext4_cache_extents(inode, eh);
+	}
+	return bh;
+errout:
+	put_bh(bh);
+	return ERR_PTR(err);
+
+}
+
+#define read_extent_tree_block(inode, idx, depth, flags)		\
+	__read_extent_tree_block(__func__, __LINE__, (inode), (idx),	\
+				 (depth), (flags))
+
+/*
+ * This function is called to cache a file's extent information in the
+ * extent status tree
+ */
+int ext4_ext_precache(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_ext_path *path = NULL;
+	struct buffer_head *bh;
+	int i = 0, depth, ret = 0;
+
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		return 0;	/* not an extent-mapped inode */
+
+	down_read(&ei->i_data_sem);
+	depth = ext_depth(inode);
+
+	/* Don't cache anything if there are no external extent blocks */
+	if (!depth) {
+		up_read(&ei->i_data_sem);
+		return ret;
+	}
+
+	path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
+		       GFP_NOFS);
+	if (path == NULL) {
+		up_read(&ei->i_data_sem);
+		return -ENOMEM;
+	}
+
+	path[0].p_hdr = ext_inode_hdr(inode);
+	ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
+	if (ret)
+		goto out;
+	path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
+	while (i >= 0) {
+		/*
+		 * If this is a leaf block or we've reached the end of
+		 * the index block, go up
+		 */
+		if ((i == depth) ||
+		    path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
+			brelse(path[i].p_bh);
+			path[i].p_bh = NULL;
+			i--;
+			continue;
+		}
+		bh = read_extent_tree_block(inode, path[i].p_idx++,
+					    depth - i - 1,
+					    EXT4_EX_FORCE_CACHE);
+		if (IS_ERR(bh)) {
+			ret = PTR_ERR(bh);
+			break;
+		}
+		i++;
+		path[i].p_bh = bh;
+		path[i].p_hdr = ext_block_hdr(bh);
+		path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
+	}
+	ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
+out:
+	up_read(&ei->i_data_sem);
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	return ret;
+}
+
+#ifdef EXT_DEBUG
+static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
+{
+	int k, l = path->p_depth;
+
+	ext_debug(inode, "path:");
+	for (k = 0; k <= l; k++, path++) {
+		if (path->p_idx) {
+			ext_debug(inode, "  %d->%llu",
+				  le32_to_cpu(path->p_idx->ei_block),
+				  ext4_idx_pblock(path->p_idx));
+		} else if (path->p_ext) {
+			ext_debug(inode, "  %d:[%d]%d:%llu ",
+				  le32_to_cpu(path->p_ext->ee_block),
+				  ext4_ext_is_unwritten(path->p_ext),
+				  ext4_ext_get_actual_len(path->p_ext),
+				  ext4_ext_pblock(path->p_ext));
+		} else
+			ext_debug(inode, "  []");
+	}
+	ext_debug(inode, "\n");
+}
+
+static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
+{
+	int depth = ext_depth(inode);
+	struct ext4_extent_header *eh;
+	struct ext4_extent *ex;
+	int i;
+
+	if (!path)
+		return;
+
+	eh = path[depth].p_hdr;
+	ex = EXT_FIRST_EXTENT(eh);
+
+	ext_debug(inode, "Displaying leaf extents\n");
+
+	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
+		ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
+			  ext4_ext_is_unwritten(ex),
+			  ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
+	}
+	ext_debug(inode, "\n");
+}
+
+static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
+			ext4_fsblk_t newblock, int level)
+{
+	int depth = ext_depth(inode);
+	struct ext4_extent *ex;
+
+	if (depth != level) {
+		struct ext4_extent_idx *idx;
+		idx = path[level].p_idx;
+		while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
+			ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
+				  level, le32_to_cpu(idx->ei_block),
+				  ext4_idx_pblock(idx), newblock);
+			idx++;
+		}
+
+		return;
+	}
+
+	ex = path[depth].p_ext;
+	while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
+		ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
+				le32_to_cpu(ex->ee_block),
+				ext4_ext_pblock(ex),
+				ext4_ext_is_unwritten(ex),
+				ext4_ext_get_actual_len(ex),
+				newblock);
+		ex++;
+	}
+}
+
+#else
+#define ext4_ext_show_path(inode, path)
+#define ext4_ext_show_leaf(inode, path)
+#define ext4_ext_show_move(inode, path, newblock, level)
+#endif
+
+void ext4_ext_drop_refs(struct ext4_ext_path *path)
+{
+	int depth, i;
+
+	if (!path)
+		return;
+	depth = path->p_depth;
+	for (i = 0; i <= depth; i++, path++) {
+		brelse(path->p_bh);
+		path->p_bh = NULL;
+	}
+}
+
+/*
+ * ext4_ext_binsearch_idx:
+ * binary search for the closest index of the given block
+ * the header must be checked before calling this
+ */
+static void
+ext4_ext_binsearch_idx(struct inode *inode,
+			struct ext4_ext_path *path, ext4_lblk_t block)
+{
+	struct ext4_extent_header *eh = path->p_hdr;
+	struct ext4_extent_idx *r, *l, *m;
+
+
+	ext_debug(inode, "binsearch for %u(idx):  ", block);
+
+	l = EXT_FIRST_INDEX(eh) + 1;
+	r = EXT_LAST_INDEX(eh);
+	while (l <= r) {
+		m = l + (r - l) / 2;
+		if (block < le32_to_cpu(m->ei_block))
+			r = m - 1;
+		else
+			l = m + 1;
+		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
+			  le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
+			  r, le32_to_cpu(r->ei_block));
+	}
+
+	path->p_idx = l - 1;
+	ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
+		  ext4_idx_pblock(path->p_idx));
+
+#ifdef CHECK_BINSEARCH
+	{
+		struct ext4_extent_idx *chix, *ix;
+		int k;
+
+		chix = ix = EXT_FIRST_INDEX(eh);
+		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
+			if (k != 0 && le32_to_cpu(ix->ei_block) <=
+			    le32_to_cpu(ix[-1].ei_block)) {
+				printk(KERN_DEBUG "k=%d, ix=0x%p, "
+				       "first=0x%p\n", k,
+				       ix, EXT_FIRST_INDEX(eh));
+				printk(KERN_DEBUG "%u <= %u\n",
+				       le32_to_cpu(ix->ei_block),
+				       le32_to_cpu(ix[-1].ei_block));
+			}
+			BUG_ON(k && le32_to_cpu(ix->ei_block)
+					   <= le32_to_cpu(ix[-1].ei_block));
+			if (block < le32_to_cpu(ix->ei_block))
+				break;
+			chix = ix;
+		}
+		BUG_ON(chix != path->p_idx);
+	}
+#endif
+
+}
+
+/*
+ * ext4_ext_binsearch:
+ * binary search for closest extent of the given block
+ * the header must be checked before calling this
+ */
+static void
+ext4_ext_binsearch(struct inode *inode,
+		struct ext4_ext_path *path, ext4_lblk_t block)
+{
+	struct ext4_extent_header *eh = path->p_hdr;
+	struct ext4_extent *r, *l, *m;
+
+	if (eh->eh_entries == 0) {
+		/*
+		 * this leaf is empty:
+		 * we get such a leaf in split/add case
+		 */
+		return;
+	}
+
+	ext_debug(inode, "binsearch for %u:  ", block);
+
+	l = EXT_FIRST_EXTENT(eh) + 1;
+	r = EXT_LAST_EXTENT(eh);
+
+	while (l <= r) {
+		m = l + (r - l) / 2;
+		if (block < le32_to_cpu(m->ee_block))
+			r = m - 1;
+		else
+			l = m + 1;
+		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
+			  le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
+			  r, le32_to_cpu(r->ee_block));
+	}
+
+	path->p_ext = l - 1;
+	ext_debug(inode, "  -> %d:%llu:[%d]%d ",
+			le32_to_cpu(path->p_ext->ee_block),
+			ext4_ext_pblock(path->p_ext),
+			ext4_ext_is_unwritten(path->p_ext),
+			ext4_ext_get_actual_len(path->p_ext));
+
+#ifdef CHECK_BINSEARCH
+	{
+		struct ext4_extent *chex, *ex;
+		int k;
+
+		chex = ex = EXT_FIRST_EXTENT(eh);
+		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
+			BUG_ON(k && le32_to_cpu(ex->ee_block)
+					  <= le32_to_cpu(ex[-1].ee_block));
+			if (block < le32_to_cpu(ex->ee_block))
+				break;
+			chex = ex;
+		}
+		BUG_ON(chex != path->p_ext);
+	}
+#endif
+
+}
+
+void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
+{
+	struct ext4_extent_header *eh;
+
+	eh = ext_inode_hdr(inode);
+	eh->eh_depth = 0;
+	eh->eh_entries = 0;
+	eh->eh_magic = EXT4_EXT_MAGIC;
+	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
+	eh->eh_generation = 0;
+	ext4_mark_inode_dirty(handle, inode);
+}
+
+struct ext4_ext_path *
+ext4_find_extent(struct inode *inode, ext4_lblk_t block,
+		 struct ext4_ext_path **orig_path, int flags)
+{
+	struct ext4_extent_header *eh;
+	struct buffer_head *bh;
+	struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
+	short int depth, i, ppos = 0;
+	int ret;
+	gfp_t gfp_flags = GFP_NOFS;
+
+	if (flags & EXT4_EX_NOFAIL)
+		gfp_flags |= __GFP_NOFAIL;
+
+	eh = ext_inode_hdr(inode);
+	depth = ext_depth(inode);
+	if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
+		EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
+				 depth);
+		ret = -EFSCORRUPTED;
+		goto err;
+	}
+
+	if (path) {
+		ext4_ext_drop_refs(path);
+		if (depth > path[0].p_maxdepth) {
+			kfree(path);
+			*orig_path = path = NULL;
+		}
+	}
+	if (!path) {
+		/* account possible depth increase */
+		path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
+				gfp_flags);
+		if (unlikely(!path))
+			return ERR_PTR(-ENOMEM);
+		path[0].p_maxdepth = depth + 1;
+	}
+	path[0].p_hdr = eh;
+	path[0].p_bh = NULL;
+
+	i = depth;
+	if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
+		ext4_cache_extents(inode, eh);
+	/* walk through the tree */
+	while (i) {
+		ext_debug(inode, "depth %d: num %d, max %d\n",
+			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
+
+		ext4_ext_binsearch_idx(inode, path + ppos, block);
+		path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
+		path[ppos].p_depth = i;
+		path[ppos].p_ext = NULL;
+
+		bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
+		if (IS_ERR(bh)) {
+			ret = PTR_ERR(bh);
+			goto err;
+		}
+
+		eh = ext_block_hdr(bh);
+		ppos++;
+		path[ppos].p_bh = bh;
+		path[ppos].p_hdr = eh;
+	}
+
+	path[ppos].p_depth = i;
+	path[ppos].p_ext = NULL;
+	path[ppos].p_idx = NULL;
+
+	/* find extent */
+	ext4_ext_binsearch(inode, path + ppos, block);
+	/* if not an empty leaf */
+	if (path[ppos].p_ext)
+		path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
+
+	ext4_ext_show_path(inode, path);
+
+	return path;
+
+err:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	if (orig_path)
+		*orig_path = NULL;
+	return ERR_PTR(ret);
+}
+
+/*
+ * ext4_ext_insert_index:
+ * insert new index [@logical;@ptr] into the block at @curp;
+ * check where to insert: before @curp or after @curp
+ */
+static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
+				 struct ext4_ext_path *curp,
+				 int logical, ext4_fsblk_t ptr)
+{
+	struct ext4_extent_idx *ix;
+	int len, err;
+
+	err = ext4_ext_get_access(handle, inode, curp);
+	if (err)
+		return err;
+
+	if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
+		EXT4_ERROR_INODE(inode,
+				 "logical %d == ei_block %d!",
+				 logical, le32_to_cpu(curp->p_idx->ei_block));
+		return -EFSCORRUPTED;
+	}
+
+	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
+			     >= le16_to_cpu(curp->p_hdr->eh_max))) {
+		EXT4_ERROR_INODE(inode,
+				 "eh_entries %d >= eh_max %d!",
+				 le16_to_cpu(curp->p_hdr->eh_entries),
+				 le16_to_cpu(curp->p_hdr->eh_max));
+		return -EFSCORRUPTED;
+	}
+
+	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
+		/* insert after */
+		ext_debug(inode, "insert new index %d after: %llu\n",
+			  logical, ptr);
+		ix = curp->p_idx + 1;
+	} else {
+		/* insert before */
+		ext_debug(inode, "insert new index %d before: %llu\n",
+			  logical, ptr);
+		ix = curp->p_idx;
+	}
+
+	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
+		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
+		return -EFSCORRUPTED;
+	}
+
+	len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
+	BUG_ON(len < 0);
+	if (len > 0) {
+		ext_debug(inode, "insert new index %d: "
+				"move %d indices from 0x%p to 0x%p\n",
+				logical, len, ix, ix + 1);
+		memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
+	}
+
+	ix->ei_block = cpu_to_le32(logical);
+	ext4_idx_store_pblock(ix, ptr);
+	le16_add_cpu(&curp->p_hdr->eh_entries, 1);
+
+	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
+		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
+		return -EFSCORRUPTED;
+	}
+
+	err = ext4_ext_dirty(handle, inode, curp);
+	ext4_std_error(inode->i_sb, err);
+
+	return err;
+}
+
+/*
+ * ext4_ext_split:
+ * inserts new subtree into the path, using free index entry
+ * at depth @at:
+ * - allocates all needed blocks (new leaf and all intermediate index blocks)
+ * - makes decision where to split
+ * - moves remaining extents and index entries (right to the split point)
+ *   into the newly allocated blocks
+ * - initializes subtree
+ */
+static int ext4_ext_split(handle_t *handle, struct inode *inode,
+			  unsigned int flags,
+			  struct ext4_ext_path *path,
+			  struct ext4_extent *newext, int at)
+{
+	struct buffer_head *bh = NULL;
+	int depth = ext_depth(inode);
+	struct ext4_extent_header *neh;
+	struct ext4_extent_idx *fidx;
+	int i = at, k, m, a;
+	ext4_fsblk_t newblock, oldblock;
+	__le32 border;
+	ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
+	gfp_t gfp_flags = GFP_NOFS;
+	int err = 0;
+	size_t ext_size = 0;
+
+	if (flags & EXT4_EX_NOFAIL)
+		gfp_flags |= __GFP_NOFAIL;
+
+	/* make decision: where to split? */
+	/* FIXME: now decision is simplest: at current extent */
+
+	/* if current leaf will be split, then we should use
+	 * border from split point */
+	if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
+		EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
+		return -EFSCORRUPTED;
+	}
+	if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
+		border = path[depth].p_ext[1].ee_block;
+		ext_debug(inode, "leaf will be split."
+				" next leaf starts at %d\n",
+				  le32_to_cpu(border));
+	} else {
+		border = newext->ee_block;
+		ext_debug(inode, "leaf will be added."
+				" next leaf starts at %d\n",
+				le32_to_cpu(border));
+	}
+
+	/*
+	 * If error occurs, then we break processing
+	 * and mark filesystem read-only. index won't
+	 * be inserted and tree will be in consistent
+	 * state. Next mount will repair buffers too.
+	 */
+
+	/*
+	 * Get array to track all allocated blocks.
+	 * We need this to handle errors and free blocks
+	 * upon them.
+	 */
+	ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);
+	if (!ablocks)
+		return -ENOMEM;
+
+	/* allocate all needed blocks */
+	ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);
+	for (a = 0; a < depth - at; a++) {
+		newblock = ext4_ext_new_meta_block(handle, inode, path,
+						   newext, &err, flags);
+		if (newblock == 0)
+			goto cleanup;
+		ablocks[a] = newblock;
+	}
+
+	/* initialize new leaf */
+	newblock = ablocks[--a];
+	if (unlikely(newblock == 0)) {
+		EXT4_ERROR_INODE(inode, "newblock == 0!");
+		err = -EFSCORRUPTED;
+		goto cleanup;
+	}
+	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
+	if (unlikely(!bh)) {
+		err = -ENOMEM;
+		goto cleanup;
+	}
+	lock_buffer(bh);
+
+	err = ext4_journal_get_create_access(handle, bh);
+	if (err)
+		goto cleanup;
+
+	neh = ext_block_hdr(bh);
+	neh->eh_entries = 0;
+	neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
+	neh->eh_magic = EXT4_EXT_MAGIC;
+	neh->eh_depth = 0;
+	neh->eh_generation = 0;
+
+	/* move remainder of path[depth] to the new leaf */
+	if (unlikely(path[depth].p_hdr->eh_entries !=
+		     path[depth].p_hdr->eh_max)) {
+		EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
+				 path[depth].p_hdr->eh_entries,
+				 path[depth].p_hdr->eh_max);
+		err = -EFSCORRUPTED;
+		goto cleanup;
+	}
+	/* start copy from next extent */
+	m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
+	ext4_ext_show_move(inode, path, newblock, depth);
+	if (m) {
+		struct ext4_extent *ex;
+		ex = EXT_FIRST_EXTENT(neh);
+		memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
+		le16_add_cpu(&neh->eh_entries, m);
+	}
+
+	/* zero out unused area in the extent block */
+	ext_size = sizeof(struct ext4_extent_header) +
+		sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
+	memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
+	ext4_extent_block_csum_set(inode, neh);
+	set_buffer_uptodate(bh);
+	unlock_buffer(bh);
+
+	err = ext4_handle_dirty_metadata(handle, inode, bh);
+	if (err)
+		goto cleanup;
+	brelse(bh);
+	bh = NULL;
+
+	/* correct old leaf */
+	if (m) {
+		err = ext4_ext_get_access(handle, inode, path + depth);
+		if (err)
+			goto cleanup;
+		le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
+		err = ext4_ext_dirty(handle, inode, path + depth);
+		if (err)
+			goto cleanup;
+
+	}
+
+	/* create intermediate indexes */
+	k = depth - at - 1;
+	if (unlikely(k < 0)) {
+		EXT4_ERROR_INODE(inode, "k %d < 0!", k);
+		err = -EFSCORRUPTED;
+		goto cleanup;
+	}
+	if (k)
+		ext_debug(inode, "create %d intermediate indices\n", k);
+	/* insert new index into current index block */
+	/* current depth stored in i var */
+	i = depth - 1;
+	while (k--) {
+		oldblock = newblock;
+		newblock = ablocks[--a];
+		bh = sb_getblk(inode->i_sb, newblock);
+		if (unlikely(!bh)) {
+			err = -ENOMEM;
+			goto cleanup;
+		}
+		lock_buffer(bh);
+
+		err = ext4_journal_get_create_access(handle, bh);
+		if (err)
+			goto cleanup;
+
+		neh = ext_block_hdr(bh);
+		neh->eh_entries = cpu_to_le16(1);
+		neh->eh_magic = EXT4_EXT_MAGIC;
+		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
+		neh->eh_depth = cpu_to_le16(depth - i);
+		neh->eh_generation = 0;
+		fidx = EXT_FIRST_INDEX(neh);
+		fidx->ei_block = border;
+		ext4_idx_store_pblock(fidx, oldblock);
+
+		ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",
+				i, newblock, le32_to_cpu(border), oldblock);
+
+		/* move remainder of path[i] to the new index block */
+		if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
+					EXT_LAST_INDEX(path[i].p_hdr))) {
+			EXT4_ERROR_INODE(inode,
+					 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
+					 le32_to_cpu(path[i].p_ext->ee_block));
+			err = -EFSCORRUPTED;
+			goto cleanup;
+		}
+		/* start copy indexes */
+		m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
+		ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
+				EXT_MAX_INDEX(path[i].p_hdr));
+		ext4_ext_show_move(inode, path, newblock, i);
+		if (m) {
+			memmove(++fidx, path[i].p_idx,
+				sizeof(struct ext4_extent_idx) * m);
+			le16_add_cpu(&neh->eh_entries, m);
+		}
+		/* zero out unused area in the extent block */
+		ext_size = sizeof(struct ext4_extent_header) +
+		   (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
+		memset(bh->b_data + ext_size, 0,
+			inode->i_sb->s_blocksize - ext_size);
+		ext4_extent_block_csum_set(inode, neh);
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+
+		err = ext4_handle_dirty_metadata(handle, inode, bh);
+		if (err)
+			goto cleanup;
+		brelse(bh);
+		bh = NULL;
+
+		/* correct old index */
+		if (m) {
+			err = ext4_ext_get_access(handle, inode, path + i);
+			if (err)
+				goto cleanup;
+			le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
+			err = ext4_ext_dirty(handle, inode, path + i);
+			if (err)
+				goto cleanup;
+		}
+
+		i--;
+	}
+
+	/* insert new index */
+	err = ext4_ext_insert_index(handle, inode, path + at,
+				    le32_to_cpu(border), newblock);
+
+cleanup:
+	if (bh) {
+		if (buffer_locked(bh))
+			unlock_buffer(bh);
+		brelse(bh);
+	}
+
+	if (err) {
+		/* free all allocated blocks in error case */
+		for (i = 0; i < depth; i++) {
+			if (!ablocks[i])
+				continue;
+			ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
+					 EXT4_FREE_BLOCKS_METADATA);
+		}
+	}
+	kfree(ablocks);
+
+	return err;
+}
+
+/*
+ * ext4_ext_grow_indepth:
+ * implements tree growing procedure:
+ * - allocates new block
+ * - moves top-level data (index block or leaf) into the new block
+ * - initializes new top-level, creating index that points to the
+ *   just created block
+ */
+static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
+				 unsigned int flags)
+{
+	struct ext4_extent_header *neh;
+	struct buffer_head *bh;
+	ext4_fsblk_t newblock, goal = 0;
+	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
+	int err = 0;
+	size_t ext_size = 0;
+
+	/* Try to prepend new index to old one */
+	if (ext_depth(inode))
+		goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
+	if (goal > le32_to_cpu(es->s_first_data_block)) {
+		flags |= EXT4_MB_HINT_TRY_GOAL;
+		goal--;
+	} else
+		goal = ext4_inode_to_goal_block(inode);
+	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
+					NULL, &err);
+	if (newblock == 0)
+		return err;
+
+	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
+	if (unlikely(!bh))
+		return -ENOMEM;
+	lock_buffer(bh);
+
+	err = ext4_journal_get_create_access(handle, bh);
+	if (err) {
+		unlock_buffer(bh);
+		goto out;
+	}
+
+	ext_size = sizeof(EXT4_I(inode)->i_data);
+	/* move top-level index/leaf into new block */
+	memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
+	/* zero out unused area in the extent block */
+	memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
+
+	/* set size of new block */
+	neh = ext_block_hdr(bh);
+	/* old root could have indexes or leaves
+	 * so calculate e_max right way */
+	if (ext_depth(inode))
+		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
+	else
+		neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
+	neh->eh_magic = EXT4_EXT_MAGIC;
+	ext4_extent_block_csum_set(inode, neh);
+	set_buffer_uptodate(bh);
+	unlock_buffer(bh);
+
+	err = ext4_handle_dirty_metadata(handle, inode, bh);
+	if (err)
+		goto out;
+
+	/* Update top-level index: num,max,pointer */
+	neh = ext_inode_hdr(inode);
+	neh->eh_entries = cpu_to_le16(1);
+	ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
+	if (neh->eh_depth == 0) {
+		/* Root extent block becomes index block */
+		neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
+		EXT_FIRST_INDEX(neh)->ei_block =
+			EXT_FIRST_EXTENT(neh)->ee_block;
+	}
+	ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",
+		  le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
+		  le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
+		  ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
+
+	le16_add_cpu(&neh->eh_depth, 1);
+	err = ext4_mark_inode_dirty(handle, inode);
+out:
+	brelse(bh);
+
+	return err;
+}
+
+/*
+ * ext4_ext_create_new_leaf:
+ * finds empty index and adds new leaf.
+ * if no free index is found, then it requests in-depth growing.
+ */
+static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
+				    unsigned int mb_flags,
+				    unsigned int gb_flags,
+				    struct ext4_ext_path **ppath,
+				    struct ext4_extent *newext)
+{
+	struct ext4_ext_path *path = *ppath;
+	struct ext4_ext_path *curp;
+	int depth, i, err = 0;
+
+repeat:
+	i = depth = ext_depth(inode);
+
+	/* walk up to the tree and look for free index entry */
+	curp = path + depth;
+	while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
+		i--;
+		curp--;
+	}
+
+	/* we use already allocated block for index block,
+	 * so subsequent data blocks should be contiguous */
+	if (EXT_HAS_FREE_INDEX(curp)) {
+		/* if we found index with free entry, then use that
+		 * entry: create all needed subtree and add new leaf */
+		err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
+		if (err)
+			goto out;
+
+		/* refill path */
+		path = ext4_find_extent(inode,
+				    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
+				    ppath, gb_flags);
+		if (IS_ERR(path))
+			err = PTR_ERR(path);
+	} else {
+		/* tree is full, time to grow in depth */
+		err = ext4_ext_grow_indepth(handle, inode, mb_flags);
+		if (err)
+			goto out;
+
+		/* refill path */
+		path = ext4_find_extent(inode,
+				   (ext4_lblk_t)le32_to_cpu(newext->ee_block),
+				    ppath, gb_flags);
+		if (IS_ERR(path)) {
+			err = PTR_ERR(path);
+			goto out;
+		}
+
+		/*
+		 * only first (depth 0 -> 1) produces free space;
+		 * in all other cases we have to split the grown tree
+		 */
+		depth = ext_depth(inode);
+		if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
+			/* now we need to split */
+			goto repeat;
+		}
+	}
+
+out:
+	return err;
+}
+
+/*
+ * search the closest allocated block to the left for *logical
+ * and returns it at @logical + it's physical address at @phys
+ * if *logical is the smallest allocated block, the function
+ * returns 0 at @phys
+ * return value contains 0 (success) or error code
+ */
+static int ext4_ext_search_left(struct inode *inode,
+				struct ext4_ext_path *path,
+				ext4_lblk_t *logical, ext4_fsblk_t *phys)
+{
+	struct ext4_extent_idx *ix;
+	struct ext4_extent *ex;
+	int depth, ee_len;
+
+	if (unlikely(path == NULL)) {
+		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
+		return -EFSCORRUPTED;
+	}
+	depth = path->p_depth;
+	*phys = 0;
+
+	if (depth == 0 && path->p_ext == NULL)
+		return 0;
+
+	/* usually extent in the path covers blocks smaller
+	 * then *logical, but it can be that extent is the
+	 * first one in the file */
+
+	ex = path[depth].p_ext;
+	ee_len = ext4_ext_get_actual_len(ex);
+	if (*logical < le32_to_cpu(ex->ee_block)) {
+		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
+			EXT4_ERROR_INODE(inode,
+					 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
+					 *logical, le32_to_cpu(ex->ee_block));
+			return -EFSCORRUPTED;
+		}
+		while (--depth >= 0) {
+			ix = path[depth].p_idx;
+			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
+				EXT4_ERROR_INODE(inode,
+				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
+				  ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
+				  EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
+		le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
+				  depth);
+				return -EFSCORRUPTED;
+			}
+		}
+		return 0;
+	}
+
+	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
+		EXT4_ERROR_INODE(inode,
+				 "logical %d < ee_block %d + ee_len %d!",
+				 *logical, le32_to_cpu(ex->ee_block), ee_len);
+		return -EFSCORRUPTED;
+	}
+
+	*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
+	*phys = ext4_ext_pblock(ex) + ee_len - 1;
+	return 0;
+}
+
+/*
+ * Search the closest allocated block to the right for *logical
+ * and returns it at @logical + it's physical address at @phys.
+ * If not exists, return 0 and @phys is set to 0. We will return
+ * 1 which means we found an allocated block and ret_ex is valid.
+ * Or return a (< 0) error code.
+ */
+static int ext4_ext_search_right(struct inode *inode,
+				 struct ext4_ext_path *path,
+				 ext4_lblk_t *logical, ext4_fsblk_t *phys,
+				 struct ext4_extent *ret_ex)
+{
+	struct buffer_head *bh = NULL;
+	struct ext4_extent_header *eh;
+	struct ext4_extent_idx *ix;
+	struct ext4_extent *ex;
+	int depth;	/* Note, NOT eh_depth; depth from top of tree */
+	int ee_len;
+
+	if (unlikely(path == NULL)) {
+		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
+		return -EFSCORRUPTED;
+	}
+	depth = path->p_depth;
+	*phys = 0;
+
+	if (depth == 0 && path->p_ext == NULL)
+		return 0;
+
+	/* usually extent in the path covers blocks smaller
+	 * then *logical, but it can be that extent is the
+	 * first one in the file */
+
+	ex = path[depth].p_ext;
+	ee_len = ext4_ext_get_actual_len(ex);
+	if (*logical < le32_to_cpu(ex->ee_block)) {
+		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
+			EXT4_ERROR_INODE(inode,
+					 "first_extent(path[%d].p_hdr) != ex",
+					 depth);
+			return -EFSCORRUPTED;
+		}
+		while (--depth >= 0) {
+			ix = path[depth].p_idx;
+			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
+				EXT4_ERROR_INODE(inode,
+						 "ix != EXT_FIRST_INDEX *logical %d!",
+						 *logical);
+				return -EFSCORRUPTED;
+			}
+		}
+		goto found_extent;
+	}
+
+	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
+		EXT4_ERROR_INODE(inode,
+				 "logical %d < ee_block %d + ee_len %d!",
+				 *logical, le32_to_cpu(ex->ee_block), ee_len);
+		return -EFSCORRUPTED;
+	}
+
+	if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
+		/* next allocated block in this leaf */
+		ex++;
+		goto found_extent;
+	}
+
+	/* go up and search for index to the right */
+	while (--depth >= 0) {
+		ix = path[depth].p_idx;
+		if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
+			goto got_index;
+	}
+
+	/* we've gone up to the root and found no index to the right */
+	return 0;
+
+got_index:
+	/* we've found index to the right, let's
+	 * follow it and find the closest allocated
+	 * block to the right */
+	ix++;
+	while (++depth < path->p_depth) {
+		/* subtract from p_depth to get proper eh_depth */
+		bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
+		if (IS_ERR(bh))
+			return PTR_ERR(bh);
+		eh = ext_block_hdr(bh);
+		ix = EXT_FIRST_INDEX(eh);
+		put_bh(bh);
+	}
+
+	bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+	eh = ext_block_hdr(bh);
+	ex = EXT_FIRST_EXTENT(eh);
+found_extent:
+	*logical = le32_to_cpu(ex->ee_block);
+	*phys = ext4_ext_pblock(ex);
+	if (ret_ex)
+		*ret_ex = *ex;
+	if (bh)
+		put_bh(bh);
+	return 1;
+}
+
+/*
+ * ext4_ext_next_allocated_block:
+ * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
+ * NOTE: it considers block number from index entry as
+ * allocated block. Thus, index entries have to be consistent
+ * with leaves.
+ */
+ext4_lblk_t
+ext4_ext_next_allocated_block(struct ext4_ext_path *path)
+{
+	int depth;
+
+	BUG_ON(path == NULL);
+	depth = path->p_depth;
+
+	if (depth == 0 && path->p_ext == NULL)
+		return EXT_MAX_BLOCKS;
+
+	while (depth >= 0) {
+		struct ext4_ext_path *p = &path[depth];
+
+		if (depth == path->p_depth) {
+			/* leaf */
+			if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
+				return le32_to_cpu(p->p_ext[1].ee_block);
+		} else {
+			/* index */
+			if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
+				return le32_to_cpu(p->p_idx[1].ei_block);
+		}
+		depth--;
+	}
+
+	return EXT_MAX_BLOCKS;
+}
+
+/*
+ * ext4_ext_next_leaf_block:
+ * returns first allocated block from next leaf or EXT_MAX_BLOCKS
+ */
+static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
+{
+	int depth;
+
+	BUG_ON(path == NULL);
+	depth = path->p_depth;
+
+	/* zero-tree has no leaf blocks at all */
+	if (depth == 0)
+		return EXT_MAX_BLOCKS;
+
+	/* go to index block */
+	depth--;
+
+	while (depth >= 0) {
+		if (path[depth].p_idx !=
+				EXT_LAST_INDEX(path[depth].p_hdr))
+			return (ext4_lblk_t)
+				le32_to_cpu(path[depth].p_idx[1].ei_block);
+		depth--;
+	}
+
+	return EXT_MAX_BLOCKS;
+}
+
+/*
+ * ext4_ext_correct_indexes:
+ * if leaf gets modified and modified extent is first in the leaf,
+ * then we have to correct all indexes above.
+ * TODO: do we need to correct tree in all cases?
+ */
+static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
+				struct ext4_ext_path *path)
+{
+	struct ext4_extent_header *eh;
+	int depth = ext_depth(inode);
+	struct ext4_extent *ex;
+	__le32 border;
+	int k, err = 0;
+
+	eh = path[depth].p_hdr;
+	ex = path[depth].p_ext;
+
+	if (unlikely(ex == NULL || eh == NULL)) {
+		EXT4_ERROR_INODE(inode,
+				 "ex %p == NULL or eh %p == NULL", ex, eh);
+		return -EFSCORRUPTED;
+	}
+
+	if (depth == 0) {
+		/* there is no tree at all */
+		return 0;
+	}
+
+	if (ex != EXT_FIRST_EXTENT(eh)) {
+		/* we correct tree if first leaf got modified only */
+		return 0;
+	}
+
+	/*
+	 * TODO: we need correction if border is smaller than current one
+	 */
+	k = depth - 1;
+	border = path[depth].p_ext->ee_block;
+	err = ext4_ext_get_access(handle, inode, path + k);
+	if (err)
+		return err;
+	path[k].p_idx->ei_block = border;
+	err = ext4_ext_dirty(handle, inode, path + k);
+	if (err)
+		return err;
+
+	while (k--) {
+		/* change all left-side indexes */
+		if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
+			break;
+		err = ext4_ext_get_access(handle, inode, path + k);
+		if (err)
+			break;
+		path[k].p_idx->ei_block = border;
+		err = ext4_ext_dirty(handle, inode, path + k);
+		if (err)
+			break;
+	}
+
+	return err;
+}
+
+static int ext4_can_extents_be_merged(struct inode *inode,
+				      struct ext4_extent *ex1,
+				      struct ext4_extent *ex2)
+{
+	unsigned short ext1_ee_len, ext2_ee_len;
+
+	if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
+		return 0;
+
+	ext1_ee_len = ext4_ext_get_actual_len(ex1);
+	ext2_ee_len = ext4_ext_get_actual_len(ex2);
+
+	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
+			le32_to_cpu(ex2->ee_block))
+		return 0;
+
+	if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
+		return 0;
+
+	if (ext4_ext_is_unwritten(ex1) &&
+	    ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
+		return 0;
+#ifdef AGGRESSIVE_TEST
+	if (ext1_ee_len >= 4)
+		return 0;
+#endif
+
+	if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
+		return 1;
+	return 0;
+}
+
+/*
+ * This function tries to merge the "ex" extent to the next extent in the tree.
+ * It always tries to merge towards right. If you want to merge towards
+ * left, pass "ex - 1" as argument instead of "ex".
+ * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
+ * 1 if they got merged.
+ */
+static int ext4_ext_try_to_merge_right(struct inode *inode,
+				 struct ext4_ext_path *path,
+				 struct ext4_extent *ex)
+{
+	struct ext4_extent_header *eh;
+	unsigned int depth, len;
+	int merge_done = 0, unwritten;
+
+	depth = ext_depth(inode);
+	BUG_ON(path[depth].p_hdr == NULL);
+	eh = path[depth].p_hdr;
+
+	while (ex < EXT_LAST_EXTENT(eh)) {
+		if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
+			break;
+		/* merge with next extent! */
+		unwritten = ext4_ext_is_unwritten(ex);
+		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+				+ ext4_ext_get_actual_len(ex + 1));
+		if (unwritten)
+			ext4_ext_mark_unwritten(ex);
+
+		if (ex + 1 < EXT_LAST_EXTENT(eh)) {
+			len = (EXT_LAST_EXTENT(eh) - ex - 1)
+				* sizeof(struct ext4_extent);
+			memmove(ex + 1, ex + 2, len);
+		}
+		le16_add_cpu(&eh->eh_entries, -1);
+		merge_done = 1;
+		WARN_ON(eh->eh_entries == 0);
+		if (!eh->eh_entries)
+			EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
+	}
+
+	return merge_done;
+}
+
+/*
+ * This function does a very simple check to see if we can collapse
+ * an extent tree with a single extent tree leaf block into the inode.
+ */
+static void ext4_ext_try_to_merge_up(handle_t *handle,
+				     struct inode *inode,
+				     struct ext4_ext_path *path)
+{
+	size_t s;
+	unsigned max_root = ext4_ext_space_root(inode, 0);
+	ext4_fsblk_t blk;
+
+	if ((path[0].p_depth != 1) ||
+	    (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
+	    (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
+		return;
+
+	/*
+	 * We need to modify the block allocation bitmap and the block
+	 * group descriptor to release the extent tree block.  If we
+	 * can't get the journal credits, give up.
+	 */
+	if (ext4_journal_extend(handle, 2,
+			ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
+		return;
+
+	/*
+	 * Copy the extent data up to the inode
+	 */
+	blk = ext4_idx_pblock(path[0].p_idx);
+	s = le16_to_cpu(path[1].p_hdr->eh_entries) *
+		sizeof(struct ext4_extent_idx);
+	s += sizeof(struct ext4_extent_header);
+
+	path[1].p_maxdepth = path[0].p_maxdepth;
+	memcpy(path[0].p_hdr, path[1].p_hdr, s);
+	path[0].p_depth = 0;
+	path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
+		(path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
+	path[0].p_hdr->eh_max = cpu_to_le16(max_root);
+
+	brelse(path[1].p_bh);
+	ext4_free_blocks(handle, inode, NULL, blk, 1,
+			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
+}
+
+/*
+ * This function tries to merge the @ex extent to neighbours in the tree, then
+ * tries to collapse the extent tree into the inode.
+ */
+static void ext4_ext_try_to_merge(handle_t *handle,
+				  struct inode *inode,
+				  struct ext4_ext_path *path,
+				  struct ext4_extent *ex)
+{
+	struct ext4_extent_header *eh;
+	unsigned int depth;
+	int merge_done = 0;
+
+	depth = ext_depth(inode);
+	BUG_ON(path[depth].p_hdr == NULL);
+	eh = path[depth].p_hdr;
+
+	if (ex > EXT_FIRST_EXTENT(eh))
+		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
+
+	if (!merge_done)
+		(void) ext4_ext_try_to_merge_right(inode, path, ex);
+
+	ext4_ext_try_to_merge_up(handle, inode, path);
+}
+
+/*
+ * check if a portion of the "newext" extent overlaps with an
+ * existing extent.
+ *
+ * If there is an overlap discovered, it updates the length of the newext
+ * such that there will be no overlap, and then returns 1.
+ * If there is no overlap found, it returns 0.
+ */
+static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
+					   struct inode *inode,
+					   struct ext4_extent *newext,
+					   struct ext4_ext_path *path)
+{
+	ext4_lblk_t b1, b2;
+	unsigned int depth, len1;
+	unsigned int ret = 0;
+
+	b1 = le32_to_cpu(newext->ee_block);
+	len1 = ext4_ext_get_actual_len(newext);
+	depth = ext_depth(inode);
+	if (!path[depth].p_ext)
+		goto out;
+	b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
+
+	/*
+	 * get the next allocated block if the extent in the path
+	 * is before the requested block(s)
+	 */
+	if (b2 < b1) {
+		b2 = ext4_ext_next_allocated_block(path);
+		if (b2 == EXT_MAX_BLOCKS)
+			goto out;
+		b2 = EXT4_LBLK_CMASK(sbi, b2);
+	}
+
+	/* check for wrap through zero on extent logical start block*/
+	if (b1 + len1 < b1) {
+		len1 = EXT_MAX_BLOCKS - b1;
+		newext->ee_len = cpu_to_le16(len1);
+		ret = 1;
+	}
+
+	/* check for overlap */
+	if (b1 + len1 > b2) {
+		newext->ee_len = cpu_to_le16(b2 - b1);
+		ret = 1;
+	}
+out:
+	return ret;
+}
+
+/*
+ * ext4_ext_insert_extent:
+ * tries to merge requested extent into the existing extent or
+ * inserts requested extent as new one into the tree,
+ * creating new leaf in the no-space case.
+ */
+int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
+				struct ext4_ext_path **ppath,
+				struct ext4_extent *newext, int gb_flags)
+{
+	struct ext4_ext_path *path = *ppath;
+	struct ext4_extent_header *eh;
+	struct ext4_extent *ex, *fex;
+	struct ext4_extent *nearex; /* nearest extent */
+	struct ext4_ext_path *npath = NULL;
+	int depth, len, err;
+	ext4_lblk_t next;
+	int mb_flags = 0, unwritten;
+
+	if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+		mb_flags |= EXT4_MB_DELALLOC_RESERVED;
+	if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
+		EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
+		return -EFSCORRUPTED;
+	}
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+	eh = path[depth].p_hdr;
+	if (unlikely(path[depth].p_hdr == NULL)) {
+		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
+		return -EFSCORRUPTED;
+	}
+
+	/* try to insert block into found extent and return */
+	if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
+
+		/*
+		 * Try to see whether we should rather test the extent on
+		 * right from ex, or from the left of ex. This is because
+		 * ext4_find_extent() can return either extent on the
+		 * left, or on the right from the searched position. This
+		 * will make merging more effective.
+		 */
+		if (ex < EXT_LAST_EXTENT(eh) &&
+		    (le32_to_cpu(ex->ee_block) +
+		    ext4_ext_get_actual_len(ex) <
+		    le32_to_cpu(newext->ee_block))) {
+			ex += 1;
+			goto prepend;
+		} else if ((ex > EXT_FIRST_EXTENT(eh)) &&
+			   (le32_to_cpu(newext->ee_block) +
+			   ext4_ext_get_actual_len(newext) <
+			   le32_to_cpu(ex->ee_block)))
+			ex -= 1;
+
+		/* Try to append newex to the ex */
+		if (ext4_can_extents_be_merged(inode, ex, newext)) {
+			ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
+				  "(from %llu)\n",
+				  ext4_ext_is_unwritten(newext),
+				  ext4_ext_get_actual_len(newext),
+				  le32_to_cpu(ex->ee_block),
+				  ext4_ext_is_unwritten(ex),
+				  ext4_ext_get_actual_len(ex),
+				  ext4_ext_pblock(ex));
+			err = ext4_ext_get_access(handle, inode,
+						  path + depth);
+			if (err)
+				return err;
+			unwritten = ext4_ext_is_unwritten(ex);
+			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+					+ ext4_ext_get_actual_len(newext));
+			if (unwritten)
+				ext4_ext_mark_unwritten(ex);
+			eh = path[depth].p_hdr;
+			nearex = ex;
+			goto merge;
+		}
+
+prepend:
+		/* Try to prepend newex to the ex */
+		if (ext4_can_extents_be_merged(inode, newext, ex)) {
+			ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
+				  "(from %llu)\n",
+				  le32_to_cpu(newext->ee_block),
+				  ext4_ext_is_unwritten(newext),
+				  ext4_ext_get_actual_len(newext),
+				  le32_to_cpu(ex->ee_block),
+				  ext4_ext_is_unwritten(ex),
+				  ext4_ext_get_actual_len(ex),
+				  ext4_ext_pblock(ex));
+			err = ext4_ext_get_access(handle, inode,
+						  path + depth);
+			if (err)
+				return err;
+
+			unwritten = ext4_ext_is_unwritten(ex);
+			ex->ee_block = newext->ee_block;
+			ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
+			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+					+ ext4_ext_get_actual_len(newext));
+			if (unwritten)
+				ext4_ext_mark_unwritten(ex);
+			eh = path[depth].p_hdr;
+			nearex = ex;
+			goto merge;
+		}
+	}
+
+	depth = ext_depth(inode);
+	eh = path[depth].p_hdr;
+	if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
+		goto has_space;
+
+	/* probably next leaf has space for us? */
+	fex = EXT_LAST_EXTENT(eh);
+	next = EXT_MAX_BLOCKS;
+	if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
+		next = ext4_ext_next_leaf_block(path);
+	if (next != EXT_MAX_BLOCKS) {
+		ext_debug(inode, "next leaf block - %u\n", next);
+		BUG_ON(npath != NULL);
+		npath = ext4_find_extent(inode, next, NULL, gb_flags);
+		if (IS_ERR(npath))
+			return PTR_ERR(npath);
+		BUG_ON(npath->p_depth != path->p_depth);
+		eh = npath[depth].p_hdr;
+		if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
+			ext_debug(inode, "next leaf isn't full(%d)\n",
+				  le16_to_cpu(eh->eh_entries));
+			path = npath;
+			goto has_space;
+		}
+		ext_debug(inode, "next leaf has no free space(%d,%d)\n",
+			  le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
+	}
+
+	/*
+	 * There is no free space in the found leaf.
+	 * We're gonna add a new leaf in the tree.
+	 */
+	if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
+		mb_flags |= EXT4_MB_USE_RESERVED;
+	err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
+				       ppath, newext);
+	if (err)
+		goto cleanup;
+	depth = ext_depth(inode);
+	eh = path[depth].p_hdr;
+
+has_space:
+	nearex = path[depth].p_ext;
+
+	err = ext4_ext_get_access(handle, inode, path + depth);
+	if (err)
+		goto cleanup;
+
+	if (!nearex) {
+		/* there is no extent in this leaf, create first one */
+		ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",
+				le32_to_cpu(newext->ee_block),
+				ext4_ext_pblock(newext),
+				ext4_ext_is_unwritten(newext),
+				ext4_ext_get_actual_len(newext));
+		nearex = EXT_FIRST_EXTENT(eh);
+	} else {
+		if (le32_to_cpu(newext->ee_block)
+			   > le32_to_cpu(nearex->ee_block)) {
+			/* Insert after */
+			ext_debug(inode, "insert %u:%llu:[%d]%d before: "
+					"nearest %p\n",
+					le32_to_cpu(newext->ee_block),
+					ext4_ext_pblock(newext),
+					ext4_ext_is_unwritten(newext),
+					ext4_ext_get_actual_len(newext),
+					nearex);
+			nearex++;
+		} else {
+			/* Insert before */
+			BUG_ON(newext->ee_block == nearex->ee_block);
+			ext_debug(inode, "insert %u:%llu:[%d]%d after: "
+					"nearest %p\n",
+					le32_to_cpu(newext->ee_block),
+					ext4_ext_pblock(newext),
+					ext4_ext_is_unwritten(newext),
+					ext4_ext_get_actual_len(newext),
+					nearex);
+		}
+		len = EXT_LAST_EXTENT(eh) - nearex + 1;
+		if (len > 0) {
+			ext_debug(inode, "insert %u:%llu:[%d]%d: "
+					"move %d extents from 0x%p to 0x%p\n",
+					le32_to_cpu(newext->ee_block),
+					ext4_ext_pblock(newext),
+					ext4_ext_is_unwritten(newext),
+					ext4_ext_get_actual_len(newext),
+					len, nearex, nearex + 1);
+			memmove(nearex + 1, nearex,
+				len * sizeof(struct ext4_extent));
+		}
+	}
+
+	le16_add_cpu(&eh->eh_entries, 1);
+	path[depth].p_ext = nearex;
+	nearex->ee_block = newext->ee_block;
+	ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
+	nearex->ee_len = newext->ee_len;
+
+merge:
+	/* try to merge extents */
+	if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
+		ext4_ext_try_to_merge(handle, inode, path, nearex);
+
+
+	/* time to correct all indexes above */
+	err = ext4_ext_correct_indexes(handle, inode, path);
+	if (err)
+		goto cleanup;
+
+	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
+
+cleanup:
+	ext4_ext_drop_refs(npath);
+	kfree(npath);
+	return err;
+}
+
+static int ext4_fill_es_cache_info(struct inode *inode,
+				   ext4_lblk_t block, ext4_lblk_t num,
+				   struct fiemap_extent_info *fieinfo)
+{
+	ext4_lblk_t next, end = block + num - 1;
+	struct extent_status es;
+	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
+	unsigned int flags;
+	int err;
+
+	while (block <= end) {
+		next = 0;
+		flags = 0;
+		if (!ext4_es_lookup_extent(inode, block, &next, &es))
+			break;
+		if (ext4_es_is_unwritten(&es))
+			flags |= FIEMAP_EXTENT_UNWRITTEN;
+		if (ext4_es_is_delayed(&es))
+			flags |= (FIEMAP_EXTENT_DELALLOC |
+				  FIEMAP_EXTENT_UNKNOWN);
+		if (ext4_es_is_hole(&es))
+			flags |= EXT4_FIEMAP_EXTENT_HOLE;
+		if (next == 0)
+			flags |= FIEMAP_EXTENT_LAST;
+		if (flags & (FIEMAP_EXTENT_DELALLOC|
+			     EXT4_FIEMAP_EXTENT_HOLE))
+			es.es_pblk = 0;
+		else
+			es.es_pblk = ext4_es_pblock(&es);
+		err = fiemap_fill_next_extent(fieinfo,
+				(__u64)es.es_lblk << blksize_bits,
+				(__u64)es.es_pblk << blksize_bits,
+				(__u64)es.es_len << blksize_bits,
+				flags);
+		if (next == 0)
+			break;
+		block = next;
+		if (err < 0)
+			return err;
+		if (err == 1)
+			return 0;
+	}
+	return 0;
+}
+
+
+/*
+ * ext4_ext_determine_hole - determine hole around given block
+ * @inode:	inode we lookup in
+ * @path:	path in extent tree to @lblk
+ * @lblk:	pointer to logical block around which we want to determine hole
+ *
+ * Determine hole length (and start if easily possible) around given logical
+ * block. We don't try too hard to find the beginning of the hole but @path
+ * actually points to extent before @lblk, we provide it.
+ *
+ * The function returns the length of a hole starting at @lblk. We update @lblk
+ * to the beginning of the hole if we managed to find it.
+ */
+static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
+					   struct ext4_ext_path *path,
+					   ext4_lblk_t *lblk)
+{
+	int depth = ext_depth(inode);
+	struct ext4_extent *ex;
+	ext4_lblk_t len;
+
+	ex = path[depth].p_ext;
+	if (ex == NULL) {
+		/* there is no extent yet, so gap is [0;-] */
+		*lblk = 0;
+		len = EXT_MAX_BLOCKS;
+	} else if (*lblk < le32_to_cpu(ex->ee_block)) {
+		len = le32_to_cpu(ex->ee_block) - *lblk;
+	} else if (*lblk >= le32_to_cpu(ex->ee_block)
+			+ ext4_ext_get_actual_len(ex)) {
+		ext4_lblk_t next;
+
+		*lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
+		next = ext4_ext_next_allocated_block(path);
+		BUG_ON(next == *lblk);
+		len = next - *lblk;
+	} else {
+		BUG();
+	}
+	return len;
+}
+
+/*
+ * ext4_ext_put_gap_in_cache:
+ * calculate boundaries of the gap that the requested block fits into
+ * and cache this gap
+ */
+static void
+ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
+			  ext4_lblk_t hole_len)
+{
+	struct extent_status es;
+
+	ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
+				  hole_start + hole_len - 1, &es);
+	if (es.es_len) {
+		/* There's delayed extent containing lblock? */
+		if (es.es_lblk <= hole_start)
+			return;
+		hole_len = min(es.es_lblk - hole_start, hole_len);
+	}
+	ext_debug(inode, " -> %u:%u\n", hole_start, hole_len);
+	ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
+			      EXTENT_STATUS_HOLE);
+}
+
+/*
+ * ext4_ext_rm_idx:
+ * removes index from the index block.
+ */
+static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
+			struct ext4_ext_path *path, int depth)
+{
+	int err;
+	ext4_fsblk_t leaf;
+
+	/* free index block */
+	depth--;
+	path = path + depth;
+	leaf = ext4_idx_pblock(path->p_idx);
+	if (unlikely(path->p_hdr->eh_entries == 0)) {
+		EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
+		return -EFSCORRUPTED;
+	}
+	err = ext4_ext_get_access(handle, inode, path);
+	if (err)
+		return err;
+
+	if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
+		int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
+		len *= sizeof(struct ext4_extent_idx);
+		memmove(path->p_idx, path->p_idx + 1, len);
+	}
+
+	le16_add_cpu(&path->p_hdr->eh_entries, -1);
+	err = ext4_ext_dirty(handle, inode, path);
+	if (err)
+		return err;
+	ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
+	trace_ext4_ext_rm_idx(inode, leaf);
+
+	ext4_free_blocks(handle, inode, NULL, leaf, 1,
+			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
+
+	while (--depth >= 0) {
+		if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
+			break;
+		path--;
+		err = ext4_ext_get_access(handle, inode, path);
+		if (err)
+			break;
+		path->p_idx->ei_block = (path+1)->p_idx->ei_block;
+		err = ext4_ext_dirty(handle, inode, path);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+/*
+ * ext4_ext_calc_credits_for_single_extent:
+ * This routine returns max. credits that needed to insert an extent
+ * to the extent tree.
+ * When pass the actual path, the caller should calculate credits
+ * under i_data_sem.
+ */
+int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
+						struct ext4_ext_path *path)
+{
+	if (path) {
+		int depth = ext_depth(inode);
+		int ret = 0;
+
+		/* probably there is space in leaf? */
+		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
+				< le16_to_cpu(path[depth].p_hdr->eh_max)) {
+
+			/*
+			 *  There are some space in the leaf tree, no
+			 *  need to account for leaf block credit
+			 *
+			 *  bitmaps and block group descriptor blocks
+			 *  and other metadata blocks still need to be
+			 *  accounted.
+			 */
+			/* 1 bitmap, 1 block group descriptor */
+			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
+			return ret;
+		}
+	}
+
+	return ext4_chunk_trans_blocks(inode, nrblocks);
+}
+
+/*
+ * How many index/leaf blocks need to change/allocate to add @extents extents?
+ *
+ * If we add a single extent, then in the worse case, each tree level
+ * index/leaf need to be changed in case of the tree split.
+ *
+ * If more extents are inserted, they could cause the whole tree split more
+ * than once, but this is really rare.
+ */
+int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
+{
+	int index;
+	int depth;
+
+	/* If we are converting the inline data, only one is needed here. */
+	if (ext4_has_inline_data(inode))
+		return 1;
+
+	depth = ext_depth(inode);
+
+	if (extents <= 1)
+		index = depth * 2;
+	else
+		index = depth * 3;
+
+	return index;
+}
+
+static inline int get_default_free_blocks_flags(struct inode *inode)
+{
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
+		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
+	else if (ext4_should_journal_data(inode))
+		return EXT4_FREE_BLOCKS_FORGET;
+	return 0;
+}
+
+/*
+ * ext4_rereserve_cluster - increment the reserved cluster count when
+ *                          freeing a cluster with a pending reservation
+ *
+ * @inode - file containing the cluster
+ * @lblk - logical block in cluster to be reserved
+ *
+ * Increments the reserved cluster count and adjusts quota in a bigalloc
+ * file system when freeing a partial cluster containing at least one
+ * delayed and unwritten block.  A partial cluster meeting that
+ * requirement will have a pending reservation.  If so, the
+ * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
+ * defer reserved and allocated space accounting to a subsequent call
+ * to this function.
+ */
+static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
+
+	spin_lock(&ei->i_block_reservation_lock);
+	ei->i_reserved_data_blocks++;
+	percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
+	spin_unlock(&ei->i_block_reservation_lock);
+
+	percpu_counter_add(&sbi->s_freeclusters_counter, 1);
+	ext4_remove_pending(inode, lblk);
+}
+
+static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
+			      struct ext4_extent *ex,
+			      struct partial_cluster *partial,
+			      ext4_lblk_t from, ext4_lblk_t to)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	unsigned short ee_len = ext4_ext_get_actual_len(ex);
+	ext4_fsblk_t last_pblk, pblk;
+	ext4_lblk_t num;
+	int flags;
+
+	/* only extent tail removal is allowed */
+	if (from < le32_to_cpu(ex->ee_block) ||
+	    to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
+		ext4_error(sbi->s_sb,
+			   "strange request: removal(2) %u-%u from %u:%u",
+			   from, to, le32_to_cpu(ex->ee_block), ee_len);
+		return 0;
+	}
+
+#ifdef EXTENTS_STATS
+	spin_lock(&sbi->s_ext_stats_lock);
+	sbi->s_ext_blocks += ee_len;
+	sbi->s_ext_extents++;
+	if (ee_len < sbi->s_ext_min)
+		sbi->s_ext_min = ee_len;
+	if (ee_len > sbi->s_ext_max)
+		sbi->s_ext_max = ee_len;
+	if (ext_depth(inode) > sbi->s_depth_max)
+		sbi->s_depth_max = ext_depth(inode);
+	spin_unlock(&sbi->s_ext_stats_lock);
+#endif
+
+	trace_ext4_remove_blocks(inode, ex, from, to, partial);
+
+	/*
+	 * if we have a partial cluster, and it's different from the
+	 * cluster of the last block in the extent, we free it
+	 */
+	last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
+
+	if (partial->state != initial &&
+	    partial->pclu != EXT4_B2C(sbi, last_pblk)) {
+		if (partial->state == tofree) {
+			flags = get_default_free_blocks_flags(inode);
+			if (ext4_is_pending(inode, partial->lblk))
+				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
+			ext4_free_blocks(handle, inode, NULL,
+					 EXT4_C2B(sbi, partial->pclu),
+					 sbi->s_cluster_ratio, flags);
+			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
+				ext4_rereserve_cluster(inode, partial->lblk);
+		}
+		partial->state = initial;
+	}
+
+	num = le32_to_cpu(ex->ee_block) + ee_len - from;
+	pblk = ext4_ext_pblock(ex) + ee_len - num;
+
+	/*
+	 * We free the partial cluster at the end of the extent (if any),
+	 * unless the cluster is used by another extent (partial_cluster
+	 * state is nofree).  If a partial cluster exists here, it must be
+	 * shared with the last block in the extent.
+	 */
+	flags = get_default_free_blocks_flags(inode);
+
+	/* partial, left end cluster aligned, right end unaligned */
+	if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
+	    (EXT4_LBLK_CMASK(sbi, to) >= from) &&
+	    (partial->state != nofree)) {
+		if (ext4_is_pending(inode, to))
+			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
+		ext4_free_blocks(handle, inode, NULL,
+				 EXT4_PBLK_CMASK(sbi, last_pblk),
+				 sbi->s_cluster_ratio, flags);
+		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
+			ext4_rereserve_cluster(inode, to);
+		partial->state = initial;
+		flags = get_default_free_blocks_flags(inode);
+	}
+
+	flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
+
+	/*
+	 * For bigalloc file systems, we never free a partial cluster
+	 * at the beginning of the extent.  Instead, we check to see if we
+	 * need to free it on a subsequent call to ext4_remove_blocks,
+	 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
+	 */
+	flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
+	ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
+
+	/* reset the partial cluster if we've freed past it */
+	if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
+		partial->state = initial;
+
+	/*
+	 * If we've freed the entire extent but the beginning is not left
+	 * cluster aligned and is not marked as ineligible for freeing we
+	 * record the partial cluster at the beginning of the extent.  It
+	 * wasn't freed by the preceding ext4_free_blocks() call, and we
+	 * need to look farther to the left to determine if it's to be freed
+	 * (not shared with another extent). Else, reset the partial
+	 * cluster - we're either  done freeing or the beginning of the
+	 * extent is left cluster aligned.
+	 */
+	if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
+		if (partial->state == initial) {
+			partial->pclu = EXT4_B2C(sbi, pblk);
+			partial->lblk = from;
+			partial->state = tofree;
+		}
+	} else {
+		partial->state = initial;
+	}
+
+	return 0;
+}
+
+/*
+ * ext4_ext_rm_leaf() Removes the extents associated with the
+ * blocks appearing between "start" and "end".  Both "start"
+ * and "end" must appear in the same extent or EIO is returned.
+ *
+ * @handle: The journal handle
+ * @inode:  The files inode
+ * @path:   The path to the leaf
+ * @partial_cluster: The cluster which we'll have to free if all extents
+ *                   has been released from it.  However, if this value is
+ *                   negative, it's a cluster just to the right of the
+ *                   punched region and it must not be freed.
+ * @start:  The first block to remove
+ * @end:   The last block to remove
+ */
+static int
+ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
+		 struct ext4_ext_path *path,
+		 struct partial_cluster *partial,
+		 ext4_lblk_t start, ext4_lblk_t end)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int err = 0, correct_index = 0;
+	int depth = ext_depth(inode), credits, revoke_credits;
+	struct ext4_extent_header *eh;
+	ext4_lblk_t a, b;
+	unsigned num;
+	ext4_lblk_t ex_ee_block;
+	unsigned short ex_ee_len;
+	unsigned unwritten = 0;
+	struct ext4_extent *ex;
+	ext4_fsblk_t pblk;
+
+	/* the header must be checked already in ext4_ext_remove_space() */
+	ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
+	if (!path[depth].p_hdr)
+		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
+	eh = path[depth].p_hdr;
+	if (unlikely(path[depth].p_hdr == NULL)) {
+		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
+		return -EFSCORRUPTED;
+	}
+	/* find where to start removing */
+	ex = path[depth].p_ext;
+	if (!ex)
+		ex = EXT_LAST_EXTENT(eh);
+
+	ex_ee_block = le32_to_cpu(ex->ee_block);
+	ex_ee_len = ext4_ext_get_actual_len(ex);
+
+	trace_ext4_ext_rm_leaf(inode, start, ex, partial);
+
+	while (ex >= EXT_FIRST_EXTENT(eh) &&
+			ex_ee_block + ex_ee_len > start) {
+
+		if (ext4_ext_is_unwritten(ex))
+			unwritten = 1;
+		else
+			unwritten = 0;
+
+		ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
+			  unwritten, ex_ee_len);
+		path[depth].p_ext = ex;
+
+		a = ex_ee_block > start ? ex_ee_block : start;
+		b = ex_ee_block+ex_ee_len - 1 < end ?
+			ex_ee_block+ex_ee_len - 1 : end;
+
+		ext_debug(inode, "  border %u:%u\n", a, b);
+
+		/* If this extent is beyond the end of the hole, skip it */
+		if (end < ex_ee_block) {
+			/*
+			 * We're going to skip this extent and move to another,
+			 * so note that its first cluster is in use to avoid
+			 * freeing it when removing blocks.  Eventually, the
+			 * right edge of the truncated/punched region will
+			 * be just to the left.
+			 */
+			if (sbi->s_cluster_ratio > 1) {
+				pblk = ext4_ext_pblock(ex);
+				partial->pclu = EXT4_B2C(sbi, pblk);
+				partial->state = nofree;
+			}
+			ex--;
+			ex_ee_block = le32_to_cpu(ex->ee_block);
+			ex_ee_len = ext4_ext_get_actual_len(ex);
+			continue;
+		} else if (b != ex_ee_block + ex_ee_len - 1) {
+			EXT4_ERROR_INODE(inode,
+					 "can not handle truncate %u:%u "
+					 "on extent %u:%u",
+					 start, end, ex_ee_block,
+					 ex_ee_block + ex_ee_len - 1);
+			err = -EFSCORRUPTED;
+			goto out;
+		} else if (a != ex_ee_block) {
+			/* remove tail of the extent */
+			num = a - ex_ee_block;
+		} else {
+			/* remove whole extent: excellent! */
+			num = 0;
+		}
+		/*
+		 * 3 for leaf, sb, and inode plus 2 (bmap and group
+		 * descriptor) for each block group; assume two block
+		 * groups plus ex_ee_len/blocks_per_block_group for
+		 * the worst case
+		 */
+		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
+		if (ex == EXT_FIRST_EXTENT(eh)) {
+			correct_index = 1;
+			credits += (ext_depth(inode)) + 1;
+		}
+		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
+		/*
+		 * We may end up freeing some index blocks and data from the
+		 * punched range. Note that partial clusters are accounted for
+		 * by ext4_free_data_revoke_credits().
+		 */
+		revoke_credits =
+			ext4_free_metadata_revoke_credits(inode->i_sb,
+							  ext_depth(inode)) +
+			ext4_free_data_revoke_credits(inode, b - a + 1);
+
+		err = ext4_datasem_ensure_credits(handle, inode, credits,
+						  credits, revoke_credits);
+		if (err) {
+			if (err > 0)
+				err = -EAGAIN;
+			goto out;
+		}
+
+		err = ext4_ext_get_access(handle, inode, path + depth);
+		if (err)
+			goto out;
+
+		err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
+		if (err)
+			goto out;
+
+		if (num == 0)
+			/* this extent is removed; mark slot entirely unused */
+			ext4_ext_store_pblock(ex, 0);
+
+		ex->ee_len = cpu_to_le16(num);
+		/*
+		 * Do not mark unwritten if all the blocks in the
+		 * extent have been removed.
+		 */
+		if (unwritten && num)
+			ext4_ext_mark_unwritten(ex);
+		/*
+		 * If the extent was completely released,
+		 * we need to remove it from the leaf
+		 */
+		if (num == 0) {
+			if (end != EXT_MAX_BLOCKS - 1) {
+				/*
+				 * For hole punching, we need to scoot all the
+				 * extents up when an extent is removed so that
+				 * we dont have blank extents in the middle
+				 */
+				memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
+					sizeof(struct ext4_extent));
+
+				/* Now get rid of the one at the end */
+				memset(EXT_LAST_EXTENT(eh), 0,
+					sizeof(struct ext4_extent));
+			}
+			le16_add_cpu(&eh->eh_entries, -1);
+		}
+
+		err = ext4_ext_dirty(handle, inode, path + depth);
+		if (err)
+			goto out;
+
+		ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
+				ext4_ext_pblock(ex));
+		ex--;
+		ex_ee_block = le32_to_cpu(ex->ee_block);
+		ex_ee_len = ext4_ext_get_actual_len(ex);
+	}
+
+	if (correct_index && eh->eh_entries)
+		err = ext4_ext_correct_indexes(handle, inode, path);
+
+	/*
+	 * If there's a partial cluster and at least one extent remains in
+	 * the leaf, free the partial cluster if it isn't shared with the
+	 * current extent.  If it is shared with the current extent
+	 * we reset the partial cluster because we've reached the start of the
+	 * truncated/punched region and we're done removing blocks.
+	 */
+	if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
+		pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
+		if (partial->pclu != EXT4_B2C(sbi, pblk)) {
+			int flags = get_default_free_blocks_flags(inode);
+
+			if (ext4_is_pending(inode, partial->lblk))
+				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
+			ext4_free_blocks(handle, inode, NULL,
+					 EXT4_C2B(sbi, partial->pclu),
+					 sbi->s_cluster_ratio, flags);
+			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
+				ext4_rereserve_cluster(inode, partial->lblk);
+		}
+		partial->state = initial;
+	}
+
+	/* if this leaf is free, then we should
+	 * remove it from index block above */
+	if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
+		err = ext4_ext_rm_idx(handle, inode, path, depth);
+
+out:
+	return err;
+}
+
+/*
+ * ext4_ext_more_to_rm:
+ * returns 1 if current index has to be freed (even partial)
+ */
+static int
+ext4_ext_more_to_rm(struct ext4_ext_path *path)
+{
+	BUG_ON(path->p_idx == NULL);
+
+	if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
+		return 0;
+
+	/*
+	 * if truncate on deeper level happened, it wasn't partial,
+	 * so we have to consider current index for truncation
+	 */
+	if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
+		return 0;
+	return 1;
+}
+
+int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
+			  ext4_lblk_t end)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int depth = ext_depth(inode);
+	struct ext4_ext_path *path = NULL;
+	struct partial_cluster partial;
+	handle_t *handle;
+	int i = 0, err = 0;
+
+	partial.pclu = 0;
+	partial.lblk = 0;
+	partial.state = initial;
+
+	ext_debug(inode, "truncate since %u to %u\n", start, end);
+
+	/* probably first extent we're gonna free will be last in block */
+	handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
+			depth + 1,
+			ext4_free_metadata_revoke_credits(inode->i_sb, depth));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+again:
+	trace_ext4_ext_remove_space(inode, start, end, depth);
+
+	/*
+	 * Check if we are removing extents inside the extent tree. If that
+	 * is the case, we are going to punch a hole inside the extent tree
+	 * so we have to check whether we need to split the extent covering
+	 * the last block to remove so we can easily remove the part of it
+	 * in ext4_ext_rm_leaf().
+	 */
+	if (end < EXT_MAX_BLOCKS - 1) {
+		struct ext4_extent *ex;
+		ext4_lblk_t ee_block, ex_end, lblk;
+		ext4_fsblk_t pblk;
+
+		/* find extent for or closest extent to this block */
+		path = ext4_find_extent(inode, end, NULL,
+					EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
+		if (IS_ERR(path)) {
+			ext4_journal_stop(handle);
+			return PTR_ERR(path);
+		}
+		depth = ext_depth(inode);
+		/* Leaf not may not exist only if inode has no blocks at all */
+		ex = path[depth].p_ext;
+		if (!ex) {
+			if (depth) {
+				EXT4_ERROR_INODE(inode,
+						 "path[%d].p_hdr == NULL",
+						 depth);
+				err = -EFSCORRUPTED;
+			}
+			goto out;
+		}
+
+		ee_block = le32_to_cpu(ex->ee_block);
+		ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
+
+		/*
+		 * See if the last block is inside the extent, if so split
+		 * the extent at 'end' block so we can easily remove the
+		 * tail of the first part of the split extent in
+		 * ext4_ext_rm_leaf().
+		 */
+		if (end >= ee_block && end < ex_end) {
+
+			/*
+			 * If we're going to split the extent, note that
+			 * the cluster containing the block after 'end' is
+			 * in use to avoid freeing it when removing blocks.
+			 */
+			if (sbi->s_cluster_ratio > 1) {
+				pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
+				partial.pclu = EXT4_B2C(sbi, pblk);
+				partial.state = nofree;
+			}
+
+			/*
+			 * Split the extent in two so that 'end' is the last
+			 * block in the first new extent. Also we should not
+			 * fail removing space due to ENOSPC so try to use
+			 * reserved block if that happens.
+			 */
+			err = ext4_force_split_extent_at(handle, inode, &path,
+							 end + 1, 1);
+			if (err < 0)
+				goto out;
+
+		} else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
+			   partial.state == initial) {
+			/*
+			 * If we're punching, there's an extent to the right.
+			 * If the partial cluster hasn't been set, set it to
+			 * that extent's first cluster and its state to nofree
+			 * so it won't be freed should it contain blocks to be
+			 * removed. If it's already set (tofree/nofree), we're
+			 * retrying and keep the original partial cluster info
+			 * so a cluster marked tofree as a result of earlier
+			 * extent removal is not lost.
+			 */
+			lblk = ex_end + 1;
+			err = ext4_ext_search_right(inode, path, &lblk, &pblk,
+						    NULL);
+			if (err < 0)
+				goto out;
+			if (pblk) {
+				partial.pclu = EXT4_B2C(sbi, pblk);
+				partial.state = nofree;
+			}
+		}
+	}
+	/*
+	 * We start scanning from right side, freeing all the blocks
+	 * after i_size and walking into the tree depth-wise.
+	 */
+	depth = ext_depth(inode);
+	if (path) {
+		int k = i = depth;
+		while (--k > 0)
+			path[k].p_block =
+				le16_to_cpu(path[k].p_hdr->eh_entries)+1;
+	} else {
+		path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
+			       GFP_NOFS | __GFP_NOFAIL);
+		if (path == NULL) {
+			ext4_journal_stop(handle);
+			return -ENOMEM;
+		}
+		path[0].p_maxdepth = path[0].p_depth = depth;
+		path[0].p_hdr = ext_inode_hdr(inode);
+		i = 0;
+
+		if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
+			err = -EFSCORRUPTED;
+			goto out;
+		}
+	}
+	err = 0;
+
+	while (i >= 0 && err == 0) {
+		if (i == depth) {
+			/* this is leaf block */
+			err = ext4_ext_rm_leaf(handle, inode, path,
+					       &partial, start, end);
+			/* root level has p_bh == NULL, brelse() eats this */
+			brelse(path[i].p_bh);
+			path[i].p_bh = NULL;
+			i--;
+			continue;
+		}
+
+		/* this is index block */
+		if (!path[i].p_hdr) {
+			ext_debug(inode, "initialize header\n");
+			path[i].p_hdr = ext_block_hdr(path[i].p_bh);
+		}
+
+		if (!path[i].p_idx) {
+			/* this level hasn't been touched yet */
+			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
+			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
+			ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
+				  path[i].p_hdr,
+				  le16_to_cpu(path[i].p_hdr->eh_entries));
+		} else {
+			/* we were already here, see at next index */
+			path[i].p_idx--;
+		}
+
+		ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
+				i, EXT_FIRST_INDEX(path[i].p_hdr),
+				path[i].p_idx);
+		if (ext4_ext_more_to_rm(path + i)) {
+			struct buffer_head *bh;
+			/* go to the next level */
+			ext_debug(inode, "move to level %d (block %llu)\n",
+				  i + 1, ext4_idx_pblock(path[i].p_idx));
+			memset(path + i + 1, 0, sizeof(*path));
+			bh = read_extent_tree_block(inode, path[i].p_idx,
+						    depth - i - 1,
+						    EXT4_EX_NOCACHE);
+			if (IS_ERR(bh)) {
+				/* should we reset i_size? */
+				err = PTR_ERR(bh);
+				break;
+			}
+			/* Yield here to deal with large extent trees.
+			 * Should be a no-op if we did IO above. */
+			cond_resched();
+			if (WARN_ON(i + 1 > depth)) {
+				err = -EFSCORRUPTED;
+				break;
+			}
+			path[i + 1].p_bh = bh;
+
+			/* save actual number of indexes since this
+			 * number is changed at the next iteration */
+			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
+			i++;
+		} else {
+			/* we finished processing this index, go up */
+			if (path[i].p_hdr->eh_entries == 0 && i > 0) {
+				/* index is empty, remove it;
+				 * handle must be already prepared by the
+				 * truncatei_leaf() */
+				err = ext4_ext_rm_idx(handle, inode, path, i);
+			}
+			/* root level has p_bh == NULL, brelse() eats this */
+			brelse(path[i].p_bh);
+			path[i].p_bh = NULL;
+			i--;
+			ext_debug(inode, "return to level %d\n", i);
+		}
+	}
+
+	trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
+					 path->p_hdr->eh_entries);
+
+	/*
+	 * if there's a partial cluster and we have removed the first extent
+	 * in the file, then we also free the partial cluster, if any
+	 */
+	if (partial.state == tofree && err == 0) {
+		int flags = get_default_free_blocks_flags(inode);
+
+		if (ext4_is_pending(inode, partial.lblk))
+			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
+		ext4_free_blocks(handle, inode, NULL,
+				 EXT4_C2B(sbi, partial.pclu),
+				 sbi->s_cluster_ratio, flags);
+		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
+			ext4_rereserve_cluster(inode, partial.lblk);
+		partial.state = initial;
+	}
+
+	/* TODO: flexible tree reduction should be here */
+	if (path->p_hdr->eh_entries == 0) {
+		/*
+		 * truncate to zero freed all the tree,
+		 * so we need to correct eh_depth
+		 */
+		err = ext4_ext_get_access(handle, inode, path);
+		if (err == 0) {
+			ext_inode_hdr(inode)->eh_depth = 0;
+			ext_inode_hdr(inode)->eh_max =
+				cpu_to_le16(ext4_ext_space_root(inode, 0));
+			err = ext4_ext_dirty(handle, inode, path);
+		}
+	}
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	path = NULL;
+	if (err == -EAGAIN)
+		goto again;
+	ext4_journal_stop(handle);
+
+	return err;
+}
+
+/*
+ * called at mount time
+ */
+void ext4_ext_init(struct super_block *sb)
+{
+	/*
+	 * possible initialization would be here
+	 */
+
+	if (ext4_has_feature_extents(sb)) {
+#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
+		printk(KERN_INFO "EXT4-fs: file extents enabled"
+#ifdef AGGRESSIVE_TEST
+		       ", aggressive tests"
+#endif
+#ifdef CHECK_BINSEARCH
+		       ", check binsearch"
+#endif
+#ifdef EXTENTS_STATS
+		       ", stats"
+#endif
+		       "\n");
+#endif
+#ifdef EXTENTS_STATS
+		spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
+		EXT4_SB(sb)->s_ext_min = 1 << 30;
+		EXT4_SB(sb)->s_ext_max = 0;
+#endif
+	}
+}
+
+/*
+ * called at umount time
+ */
+void ext4_ext_release(struct super_block *sb)
+{
+	if (!ext4_has_feature_extents(sb))
+		return;
+
+#ifdef EXTENTS_STATS
+	if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
+		struct ext4_sb_info *sbi = EXT4_SB(sb);
+		printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
+			sbi->s_ext_blocks, sbi->s_ext_extents,
+			sbi->s_ext_blocks / sbi->s_ext_extents);
+		printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
+			sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
+	}
+#endif
+}
+
+static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
+{
+	ext4_lblk_t  ee_block;
+	ext4_fsblk_t ee_pblock;
+	unsigned int ee_len;
+
+	ee_block  = le32_to_cpu(ex->ee_block);
+	ee_len    = ext4_ext_get_actual_len(ex);
+	ee_pblock = ext4_ext_pblock(ex);
+
+	if (ee_len == 0)
+		return 0;
+
+	return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
+				     EXTENT_STATUS_WRITTEN);
+}
+
+/* FIXME!! we need to try to merge to left or right after zero-out  */
+static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
+{
+	ext4_fsblk_t ee_pblock;
+	unsigned int ee_len;
+
+	ee_len    = ext4_ext_get_actual_len(ex);
+	ee_pblock = ext4_ext_pblock(ex);
+	return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
+				  ee_len);
+}
+
+/*
+ * ext4_split_extent_at() splits an extent at given block.
+ *
+ * @handle: the journal handle
+ * @inode: the file inode
+ * @path: the path to the extent
+ * @split: the logical block where the extent is splitted.
+ * @split_flags: indicates if the extent could be zeroout if split fails, and
+ *		 the states(init or unwritten) of new extents.
+ * @flags: flags used to insert new extent to extent tree.
+ *
+ *
+ * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
+ * of which are determined by split_flag.
+ *
+ * There are two cases:
+ *  a> the extent are splitted into two extent.
+ *  b> split is not needed, and just mark the extent.
+ *
+ * return 0 on success.
+ */
+static int ext4_split_extent_at(handle_t *handle,
+			     struct inode *inode,
+			     struct ext4_ext_path **ppath,
+			     ext4_lblk_t split,
+			     int split_flag,
+			     int flags)
+{
+	struct ext4_ext_path *path = *ppath;
+	ext4_fsblk_t newblock;
+	ext4_lblk_t ee_block;
+	struct ext4_extent *ex, newex, orig_ex, zero_ex;
+	struct ext4_extent *ex2 = NULL;
+	unsigned int ee_len, depth;
+	int err = 0;
+
+	BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
+	       (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
+
+	ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
+
+	ext4_ext_show_leaf(inode, path);
+
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+	ee_block = le32_to_cpu(ex->ee_block);
+	ee_len = ext4_ext_get_actual_len(ex);
+	newblock = split - ee_block + ext4_ext_pblock(ex);
+
+	BUG_ON(split < ee_block || split >= (ee_block + ee_len));
+	BUG_ON(!ext4_ext_is_unwritten(ex) &&
+	       split_flag & (EXT4_EXT_MAY_ZEROOUT |
+			     EXT4_EXT_MARK_UNWRIT1 |
+			     EXT4_EXT_MARK_UNWRIT2));
+
+	err = ext4_ext_get_access(handle, inode, path + depth);
+	if (err)
+		goto out;
+
+	if (split == ee_block) {
+		/*
+		 * case b: block @split is the block that the extent begins with
+		 * then we just change the state of the extent, and splitting
+		 * is not needed.
+		 */
+		if (split_flag & EXT4_EXT_MARK_UNWRIT2)
+			ext4_ext_mark_unwritten(ex);
+		else
+			ext4_ext_mark_initialized(ex);
+
+		if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
+			ext4_ext_try_to_merge(handle, inode, path, ex);
+
+		err = ext4_ext_dirty(handle, inode, path + path->p_depth);
+		goto out;
+	}
+
+	/* case a */
+	memcpy(&orig_ex, ex, sizeof(orig_ex));
+	ex->ee_len = cpu_to_le16(split - ee_block);
+	if (split_flag & EXT4_EXT_MARK_UNWRIT1)
+		ext4_ext_mark_unwritten(ex);
+
+	/*
+	 * path may lead to new leaf, not to original leaf any more
+	 * after ext4_ext_insert_extent() returns,
+	 */
+	err = ext4_ext_dirty(handle, inode, path + depth);
+	if (err)
+		goto fix_extent_len;
+
+	ex2 = &newex;
+	ex2->ee_block = cpu_to_le32(split);
+	ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
+	ext4_ext_store_pblock(ex2, newblock);
+	if (split_flag & EXT4_EXT_MARK_UNWRIT2)
+		ext4_ext_mark_unwritten(ex2);
+
+	err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
+	if (err != -ENOSPC && err != -EDQUOT)
+		goto out;
+
+	if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
+		if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
+			if (split_flag & EXT4_EXT_DATA_VALID1) {
+				err = ext4_ext_zeroout(inode, ex2);
+				zero_ex.ee_block = ex2->ee_block;
+				zero_ex.ee_len = cpu_to_le16(
+						ext4_ext_get_actual_len(ex2));
+				ext4_ext_store_pblock(&zero_ex,
+						      ext4_ext_pblock(ex2));
+			} else {
+				err = ext4_ext_zeroout(inode, ex);
+				zero_ex.ee_block = ex->ee_block;
+				zero_ex.ee_len = cpu_to_le16(
+						ext4_ext_get_actual_len(ex));
+				ext4_ext_store_pblock(&zero_ex,
+						      ext4_ext_pblock(ex));
+			}
+		} else {
+			err = ext4_ext_zeroout(inode, &orig_ex);
+			zero_ex.ee_block = orig_ex.ee_block;
+			zero_ex.ee_len = cpu_to_le16(
+						ext4_ext_get_actual_len(&orig_ex));
+			ext4_ext_store_pblock(&zero_ex,
+					      ext4_ext_pblock(&orig_ex));
+		}
+
+		if (!err) {
+			/* update the extent length and mark as initialized */
+			ex->ee_len = cpu_to_le16(ee_len);
+			ext4_ext_try_to_merge(handle, inode, path, ex);
+			err = ext4_ext_dirty(handle, inode, path + path->p_depth);
+			if (!err)
+				/* update extent status tree */
+				err = ext4_zeroout_es(inode, &zero_ex);
+			/* If we failed at this point, we don't know in which
+			 * state the extent tree exactly is so don't try to fix
+			 * length of the original extent as it may do even more
+			 * damage.
+			 */
+			goto out;
+		}
+	}
+
+fix_extent_len:
+	ex->ee_len = orig_ex.ee_len;
+	/*
+	 * Ignore ext4_ext_dirty return value since we are already in error path
+	 * and err is a non-zero error code.
+	 */
+	ext4_ext_dirty(handle, inode, path + path->p_depth);
+	return err;
+out:
+	ext4_ext_show_leaf(inode, path);
+	return err;
+}
+
+/*
+ * ext4_split_extents() splits an extent and mark extent which is covered
+ * by @map as split_flags indicates
+ *
+ * It may result in splitting the extent into multiple extents (up to three)
+ * There are three possibilities:
+ *   a> There is no split required
+ *   b> Splits in two extents: Split is happening at either end of the extent
+ *   c> Splits in three extents: Somone is splitting in middle of the extent
+ *
+ */
+static int ext4_split_extent(handle_t *handle,
+			      struct inode *inode,
+			      struct ext4_ext_path **ppath,
+			      struct ext4_map_blocks *map,
+			      int split_flag,
+			      int flags)
+{
+	struct ext4_ext_path *path = *ppath;
+	ext4_lblk_t ee_block;
+	struct ext4_extent *ex;
+	unsigned int ee_len, depth;
+	int err = 0;
+	int unwritten;
+	int split_flag1, flags1;
+	int allocated = map->m_len;
+
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+	ee_block = le32_to_cpu(ex->ee_block);
+	ee_len = ext4_ext_get_actual_len(ex);
+	unwritten = ext4_ext_is_unwritten(ex);
+
+	if (map->m_lblk + map->m_len < ee_block + ee_len) {
+		split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
+		flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
+		if (unwritten)
+			split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
+				       EXT4_EXT_MARK_UNWRIT2;
+		if (split_flag & EXT4_EXT_DATA_VALID2)
+			split_flag1 |= EXT4_EXT_DATA_VALID1;
+		err = ext4_split_extent_at(handle, inode, ppath,
+				map->m_lblk + map->m_len, split_flag1, flags1);
+		if (err)
+			goto out;
+	} else {
+		allocated = ee_len - (map->m_lblk - ee_block);
+	}
+	/*
+	 * Update path is required because previous ext4_split_extent_at() may
+	 * result in split of original leaf or extent zeroout.
+	 */
+	path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+	if (!ex) {
+		EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
+				 (unsigned long) map->m_lblk);
+		return -EFSCORRUPTED;
+	}
+	unwritten = ext4_ext_is_unwritten(ex);
+	split_flag1 = 0;
+
+	if (map->m_lblk >= ee_block) {
+		split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
+		if (unwritten) {
+			split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
+			split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
+						     EXT4_EXT_MARK_UNWRIT2);
+		}
+		err = ext4_split_extent_at(handle, inode, ppath,
+				map->m_lblk, split_flag1, flags);
+		if (err)
+			goto out;
+	}
+
+	ext4_ext_show_leaf(inode, path);
+out:
+	return err ? err : allocated;
+}
+
+/*
+ * This function is called by ext4_ext_map_blocks() if someone tries to write
+ * to an unwritten extent. It may result in splitting the unwritten
+ * extent into multiple extents (up to three - one initialized and two
+ * unwritten).
+ * There are three possibilities:
+ *   a> There is no split required: Entire extent should be initialized
+ *   b> Splits in two extents: Write is happening at either end of the extent
+ *   c> Splits in three extents: Somone is writing in middle of the extent
+ *
+ * Pre-conditions:
+ *  - The extent pointed to by 'path' is unwritten.
+ *  - The extent pointed to by 'path' contains a superset
+ *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
+ *
+ * Post-conditions on success:
+ *  - the returned value is the number of blocks beyond map->l_lblk
+ *    that are allocated and initialized.
+ *    It is guaranteed to be >= map->m_len.
+ */
+static int ext4_ext_convert_to_initialized(handle_t *handle,
+					   struct inode *inode,
+					   struct ext4_map_blocks *map,
+					   struct ext4_ext_path **ppath,
+					   int flags)
+{
+	struct ext4_ext_path *path = *ppath;
+	struct ext4_sb_info *sbi;
+	struct ext4_extent_header *eh;
+	struct ext4_map_blocks split_map;
+	struct ext4_extent zero_ex1, zero_ex2;
+	struct ext4_extent *ex, *abut_ex;
+	ext4_lblk_t ee_block, eof_block;
+	unsigned int ee_len, depth, map_len = map->m_len;
+	int allocated = 0, max_zeroout = 0;
+	int err = 0;
+	int split_flag = EXT4_EXT_DATA_VALID2;
+
+	ext_debug(inode, "logical block %llu, max_blocks %u\n",
+		  (unsigned long long)map->m_lblk, map_len);
+
+	sbi = EXT4_SB(inode->i_sb);
+	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
+			>> inode->i_sb->s_blocksize_bits;
+	if (eof_block < map->m_lblk + map_len)
+		eof_block = map->m_lblk + map_len;
+
+	depth = ext_depth(inode);
+	eh = path[depth].p_hdr;
+	ex = path[depth].p_ext;
+	ee_block = le32_to_cpu(ex->ee_block);
+	ee_len = ext4_ext_get_actual_len(ex);
+	zero_ex1.ee_len = 0;
+	zero_ex2.ee_len = 0;
+
+	trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
+
+	/* Pre-conditions */
+	BUG_ON(!ext4_ext_is_unwritten(ex));
+	BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
+
+	/*
+	 * Attempt to transfer newly initialized blocks from the currently
+	 * unwritten extent to its neighbor. This is much cheaper
+	 * than an insertion followed by a merge as those involve costly
+	 * memmove() calls. Transferring to the left is the common case in
+	 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
+	 * followed by append writes.
+	 *
+	 * Limitations of the current logic:
+	 *  - L1: we do not deal with writes covering the whole extent.
+	 *    This would require removing the extent if the transfer
+	 *    is possible.
+	 *  - L2: we only attempt to merge with an extent stored in the
+	 *    same extent tree node.
+	 */
+	if ((map->m_lblk == ee_block) &&
+		/* See if we can merge left */
+		(map_len < ee_len) &&		/*L1*/
+		(ex > EXT_FIRST_EXTENT(eh))) {	/*L2*/
+		ext4_lblk_t prev_lblk;
+		ext4_fsblk_t prev_pblk, ee_pblk;
+		unsigned int prev_len;
+
+		abut_ex = ex - 1;
+		prev_lblk = le32_to_cpu(abut_ex->ee_block);
+		prev_len = ext4_ext_get_actual_len(abut_ex);
+		prev_pblk = ext4_ext_pblock(abut_ex);
+		ee_pblk = ext4_ext_pblock(ex);
+
+		/*
+		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
+		 * upon those conditions:
+		 * - C1: abut_ex is initialized,
+		 * - C2: abut_ex is logically abutting ex,
+		 * - C3: abut_ex is physically abutting ex,
+		 * - C4: abut_ex can receive the additional blocks without
+		 *   overflowing the (initialized) length limit.
+		 */
+		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
+			((prev_lblk + prev_len) == ee_block) &&		/*C2*/
+			((prev_pblk + prev_len) == ee_pblk) &&		/*C3*/
+			(prev_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
+			err = ext4_ext_get_access(handle, inode, path + depth);
+			if (err)
+				goto out;
+
+			trace_ext4_ext_convert_to_initialized_fastpath(inode,
+				map, ex, abut_ex);
+
+			/* Shift the start of ex by 'map_len' blocks */
+			ex->ee_block = cpu_to_le32(ee_block + map_len);
+			ext4_ext_store_pblock(ex, ee_pblk + map_len);
+			ex->ee_len = cpu_to_le16(ee_len - map_len);
+			ext4_ext_mark_unwritten(ex); /* Restore the flag */
+
+			/* Extend abut_ex by 'map_len' blocks */
+			abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
+
+			/* Result: number of initialized blocks past m_lblk */
+			allocated = map_len;
+		}
+	} else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
+		   (map_len < ee_len) &&	/*L1*/
+		   ex < EXT_LAST_EXTENT(eh)) {	/*L2*/
+		/* See if we can merge right */
+		ext4_lblk_t next_lblk;
+		ext4_fsblk_t next_pblk, ee_pblk;
+		unsigned int next_len;
+
+		abut_ex = ex + 1;
+		next_lblk = le32_to_cpu(abut_ex->ee_block);
+		next_len = ext4_ext_get_actual_len(abut_ex);
+		next_pblk = ext4_ext_pblock(abut_ex);
+		ee_pblk = ext4_ext_pblock(ex);
+
+		/*
+		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
+		 * upon those conditions:
+		 * - C1: abut_ex is initialized,
+		 * - C2: abut_ex is logically abutting ex,
+		 * - C3: abut_ex is physically abutting ex,
+		 * - C4: abut_ex can receive the additional blocks without
+		 *   overflowing the (initialized) length limit.
+		 */
+		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
+		    ((map->m_lblk + map_len) == next_lblk) &&		/*C2*/
+		    ((ee_pblk + ee_len) == next_pblk) &&		/*C3*/
+		    (next_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
+			err = ext4_ext_get_access(handle, inode, path + depth);
+			if (err)
+				goto out;
+
+			trace_ext4_ext_convert_to_initialized_fastpath(inode,
+				map, ex, abut_ex);
+
+			/* Shift the start of abut_ex by 'map_len' blocks */
+			abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
+			ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
+			ex->ee_len = cpu_to_le16(ee_len - map_len);
+			ext4_ext_mark_unwritten(ex); /* Restore the flag */
+
+			/* Extend abut_ex by 'map_len' blocks */
+			abut_ex->ee_len = cpu_to_le16(next_len + map_len);
+
+			/* Result: number of initialized blocks past m_lblk */
+			allocated = map_len;
+		}
+	}
+	if (allocated) {
+		/* Mark the block containing both extents as dirty */
+		err = ext4_ext_dirty(handle, inode, path + depth);
+
+		/* Update path to point to the right extent */
+		path[depth].p_ext = abut_ex;
+		goto out;
+	} else
+		allocated = ee_len - (map->m_lblk - ee_block);
+
+	WARN_ON(map->m_lblk < ee_block);
+	/*
+	 * It is safe to convert extent to initialized via explicit
+	 * zeroout only if extent is fully inside i_size or new_size.
+	 */
+	split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
+
+	if (EXT4_EXT_MAY_ZEROOUT & split_flag)
+		max_zeroout = sbi->s_extent_max_zeroout_kb >>
+			(inode->i_sb->s_blocksize_bits - 10);
+
+	/*
+	 * five cases:
+	 * 1. split the extent into three extents.
+	 * 2. split the extent into two extents, zeroout the head of the first
+	 *    extent.
+	 * 3. split the extent into two extents, zeroout the tail of the second
+	 *    extent.
+	 * 4. split the extent into two extents with out zeroout.
+	 * 5. no splitting needed, just possibly zeroout the head and / or the
+	 *    tail of the extent.
+	 */
+	split_map.m_lblk = map->m_lblk;
+	split_map.m_len = map->m_len;
+
+	if (max_zeroout && (allocated > split_map.m_len)) {
+		if (allocated <= max_zeroout) {
+			/* case 3 or 5 */
+			zero_ex1.ee_block =
+				 cpu_to_le32(split_map.m_lblk +
+					     split_map.m_len);
+			zero_ex1.ee_len =
+				cpu_to_le16(allocated - split_map.m_len);
+			ext4_ext_store_pblock(&zero_ex1,
+				ext4_ext_pblock(ex) + split_map.m_lblk +
+				split_map.m_len - ee_block);
+			err = ext4_ext_zeroout(inode, &zero_ex1);
+			if (err)
+				goto out;
+			split_map.m_len = allocated;
+		}
+		if (split_map.m_lblk - ee_block + split_map.m_len <
+								max_zeroout) {
+			/* case 2 or 5 */
+			if (split_map.m_lblk != ee_block) {
+				zero_ex2.ee_block = ex->ee_block;
+				zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
+							ee_block);
+				ext4_ext_store_pblock(&zero_ex2,
+						      ext4_ext_pblock(ex));
+				err = ext4_ext_zeroout(inode, &zero_ex2);
+				if (err)
+					goto out;
+			}
+
+			split_map.m_len += split_map.m_lblk - ee_block;
+			split_map.m_lblk = ee_block;
+			allocated = map->m_len;
+		}
+	}
+
+	err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
+				flags);
+	if (err > 0)
+		err = 0;
+out:
+	/* If we have gotten a failure, don't zero out status tree */
+	if (!err) {
+		err = ext4_zeroout_es(inode, &zero_ex1);
+		if (!err)
+			err = ext4_zeroout_es(inode, &zero_ex2);
+	}
+	return err ? err : allocated;
+}
+
+/*
+ * This function is called by ext4_ext_map_blocks() from
+ * ext4_get_blocks_dio_write() when DIO to write
+ * to an unwritten extent.
+ *
+ * Writing to an unwritten extent may result in splitting the unwritten
+ * extent into multiple initialized/unwritten extents (up to three)
+ * There are three possibilities:
+ *   a> There is no split required: Entire extent should be unwritten
+ *   b> Splits in two extents: Write is happening at either end of the extent
+ *   c> Splits in three extents: Somone is writing in middle of the extent
+ *
+ * This works the same way in the case of initialized -> unwritten conversion.
+ *
+ * One of more index blocks maybe needed if the extent tree grow after
+ * the unwritten extent split. To prevent ENOSPC occur at the IO
+ * complete, we need to split the unwritten extent before DIO submit
+ * the IO. The unwritten extent called at this time will be split
+ * into three unwritten extent(at most). After IO complete, the part
+ * being filled will be convert to initialized by the end_io callback function
+ * via ext4_convert_unwritten_extents().
+ *
+ * Returns the size of unwritten extent to be written on success.
+ */
+static int ext4_split_convert_extents(handle_t *handle,
+					struct inode *inode,
+					struct ext4_map_blocks *map,
+					struct ext4_ext_path **ppath,
+					int flags)
+{
+	struct ext4_ext_path *path = *ppath;
+	ext4_lblk_t eof_block;
+	ext4_lblk_t ee_block;
+	struct ext4_extent *ex;
+	unsigned int ee_len;
+	int split_flag = 0, depth;
+
+	ext_debug(inode, "logical block %llu, max_blocks %u\n",
+		  (unsigned long long)map->m_lblk, map->m_len);
+
+	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
+			>> inode->i_sb->s_blocksize_bits;
+	if (eof_block < map->m_lblk + map->m_len)
+		eof_block = map->m_lblk + map->m_len;
+	/*
+	 * It is safe to convert extent to initialized via explicit
+	 * zeroout only if extent is fully inside i_size or new_size.
+	 */
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+	ee_block = le32_to_cpu(ex->ee_block);
+	ee_len = ext4_ext_get_actual_len(ex);
+
+	/* Convert to unwritten */
+	if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
+		split_flag |= EXT4_EXT_DATA_VALID1;
+	/* Convert to initialized */
+	} else if (flags & EXT4_GET_BLOCKS_CONVERT) {
+		split_flag |= ee_block + ee_len <= eof_block ?
+			      EXT4_EXT_MAY_ZEROOUT : 0;
+		split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
+	}
+	flags |= EXT4_GET_BLOCKS_PRE_IO;
+	return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
+}
+
+static int ext4_convert_unwritten_extents_endio(handle_t *handle,
+						struct inode *inode,
+						struct ext4_map_blocks *map,
+						struct ext4_ext_path **ppath)
+{
+	struct ext4_ext_path *path = *ppath;
+	struct ext4_extent *ex;
+	ext4_lblk_t ee_block;
+	unsigned int ee_len;
+	int depth;
+	int err = 0;
+
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+	ee_block = le32_to_cpu(ex->ee_block);
+	ee_len = ext4_ext_get_actual_len(ex);
+
+	ext_debug(inode, "logical block %llu, max_blocks %u\n",
+		  (unsigned long long)ee_block, ee_len);
+
+	/* If extent is larger than requested it is a clear sign that we still
+	 * have some extent state machine issues left. So extent_split is still
+	 * required.
+	 * TODO: Once all related issues will be fixed this situation should be
+	 * illegal.
+	 */
+	if (ee_block != map->m_lblk || ee_len > map->m_len) {
+#ifdef CONFIG_EXT4_DEBUG
+		ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
+			     " len %u; IO logical block %llu, len %u",
+			     inode->i_ino, (unsigned long long)ee_block, ee_len,
+			     (unsigned long long)map->m_lblk, map->m_len);
+#endif
+		err = ext4_split_convert_extents(handle, inode, map, ppath,
+						 EXT4_GET_BLOCKS_CONVERT);
+		if (err < 0)
+			return err;
+		path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
+		if (IS_ERR(path))
+			return PTR_ERR(path);
+		depth = ext_depth(inode);
+		ex = path[depth].p_ext;
+	}
+
+	err = ext4_ext_get_access(handle, inode, path + depth);
+	if (err)
+		goto out;
+	/* first mark the extent as initialized */
+	ext4_ext_mark_initialized(ex);
+
+	/* note: ext4_ext_correct_indexes() isn't needed here because
+	 * borders are not changed
+	 */
+	ext4_ext_try_to_merge(handle, inode, path, ex);
+
+	/* Mark modified extent as dirty */
+	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
+out:
+	ext4_ext_show_leaf(inode, path);
+	return err;
+}
+
+static int
+convert_initialized_extent(handle_t *handle, struct inode *inode,
+			   struct ext4_map_blocks *map,
+			   struct ext4_ext_path **ppath,
+			   unsigned int *allocated)
+{
+	struct ext4_ext_path *path = *ppath;
+	struct ext4_extent *ex;
+	ext4_lblk_t ee_block;
+	unsigned int ee_len;
+	int depth;
+	int err = 0;
+
+	/*
+	 * Make sure that the extent is no bigger than we support with
+	 * unwritten extent
+	 */
+	if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
+		map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
+
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+	ee_block = le32_to_cpu(ex->ee_block);
+	ee_len = ext4_ext_get_actual_len(ex);
+
+	ext_debug(inode, "logical block %llu, max_blocks %u\n",
+		  (unsigned long long)ee_block, ee_len);
+
+	if (ee_block != map->m_lblk || ee_len > map->m_len) {
+		err = ext4_split_convert_extents(handle, inode, map, ppath,
+				EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
+		if (err < 0)
+			return err;
+		path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
+		if (IS_ERR(path))
+			return PTR_ERR(path);
+		depth = ext_depth(inode);
+		ex = path[depth].p_ext;
+		if (!ex) {
+			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
+					 (unsigned long) map->m_lblk);
+			return -EFSCORRUPTED;
+		}
+	}
+
+	err = ext4_ext_get_access(handle, inode, path + depth);
+	if (err)
+		return err;
+	/* first mark the extent as unwritten */
+	ext4_ext_mark_unwritten(ex);
+
+	/* note: ext4_ext_correct_indexes() isn't needed here because
+	 * borders are not changed
+	 */
+	ext4_ext_try_to_merge(handle, inode, path, ex);
+
+	/* Mark modified extent as dirty */
+	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
+	if (err)
+		return err;
+	ext4_ext_show_leaf(inode, path);
+
+	ext4_update_inode_fsync_trans(handle, inode, 1);
+
+	map->m_flags |= EXT4_MAP_UNWRITTEN;
+	if (*allocated > map->m_len)
+		*allocated = map->m_len;
+	map->m_len = *allocated;
+	return 0;
+}
+
+static int
+ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
+			struct ext4_map_blocks *map,
+			struct ext4_ext_path **ppath, int flags,
+			unsigned int allocated, ext4_fsblk_t newblock)
+{
+	struct ext4_ext_path __maybe_unused *path = *ppath;
+	int ret = 0;
+	int err = 0;
+
+	ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
+		  (unsigned long long)map->m_lblk, map->m_len, flags,
+		  allocated);
+	ext4_ext_show_leaf(inode, path);
+
+	/*
+	 * When writing into unwritten space, we should not fail to
+	 * allocate metadata blocks for the new extent block if needed.
+	 */
+	flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
+
+	trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
+						    allocated, newblock);
+
+	/* get_block() before submitting IO, split the extent */
+	if (flags & EXT4_GET_BLOCKS_PRE_IO) {
+		ret = ext4_split_convert_extents(handle, inode, map, ppath,
+					 flags | EXT4_GET_BLOCKS_CONVERT);
+		if (ret < 0) {
+			err = ret;
+			goto out2;
+		}
+		/*
+		 * shouldn't get a 0 return when splitting an extent unless
+		 * m_len is 0 (bug) or extent has been corrupted
+		 */
+		if (unlikely(ret == 0)) {
+			EXT4_ERROR_INODE(inode,
+					 "unexpected ret == 0, m_len = %u",
+					 map->m_len);
+			err = -EFSCORRUPTED;
+			goto out2;
+		}
+		map->m_flags |= EXT4_MAP_UNWRITTEN;
+		goto out;
+	}
+	/* IO end_io complete, convert the filled extent to written */
+	if (flags & EXT4_GET_BLOCKS_CONVERT) {
+		err = ext4_convert_unwritten_extents_endio(handle, inode, map,
+							   ppath);
+		if (err < 0)
+			goto out2;
+		ext4_update_inode_fsync_trans(handle, inode, 1);
+		goto map_out;
+	}
+	/* buffered IO cases */
+	/*
+	 * repeat fallocate creation request
+	 * we already have an unwritten extent
+	 */
+	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
+		map->m_flags |= EXT4_MAP_UNWRITTEN;
+		goto map_out;
+	}
+
+	/* buffered READ or buffered write_begin() lookup */
+	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
+		/*
+		 * We have blocks reserved already.  We
+		 * return allocated blocks so that delalloc
+		 * won't do block reservation for us.  But
+		 * the buffer head will be unmapped so that
+		 * a read from the block returns 0s.
+		 */
+		map->m_flags |= EXT4_MAP_UNWRITTEN;
+		goto out1;
+	}
+
+	/*
+	 * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
+	 * For buffered writes, at writepage time, etc.  Convert a
+	 * discovered unwritten extent to written.
+	 */
+	ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
+	if (ret < 0) {
+		err = ret;
+		goto out2;
+	}
+	ext4_update_inode_fsync_trans(handle, inode, 1);
+	/*
+	 * shouldn't get a 0 return when converting an unwritten extent
+	 * unless m_len is 0 (bug) or extent has been corrupted
+	 */
+	if (unlikely(ret == 0)) {
+		EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
+				 map->m_len);
+		err = -EFSCORRUPTED;
+		goto out2;
+	}
+
+out:
+	allocated = ret;
+	map->m_flags |= EXT4_MAP_NEW;
+map_out:
+	map->m_flags |= EXT4_MAP_MAPPED;
+out1:
+	map->m_pblk = newblock;
+	if (allocated > map->m_len)
+		allocated = map->m_len;
+	map->m_len = allocated;
+	ext4_ext_show_leaf(inode, path);
+out2:
+	return err ? err : allocated;
+}
+
+/*
+ * get_implied_cluster_alloc - check to see if the requested
+ * allocation (in the map structure) overlaps with a cluster already
+ * allocated in an extent.
+ *	@sb	The filesystem superblock structure
+ *	@map	The requested lblk->pblk mapping
+ *	@ex	The extent structure which might contain an implied
+ *			cluster allocation
+ *
+ * This function is called by ext4_ext_map_blocks() after we failed to
+ * find blocks that were already in the inode's extent tree.  Hence,
+ * we know that the beginning of the requested region cannot overlap
+ * the extent from the inode's extent tree.  There are three cases we
+ * want to catch.  The first is this case:
+ *
+ *		 |--- cluster # N--|
+ *    |--- extent ---|	|---- requested region ---|
+ *			|==========|
+ *
+ * The second case that we need to test for is this one:
+ *
+ *   |--------- cluster # N ----------------|
+ *	   |--- requested region --|   |------- extent ----|
+ *	   |=======================|
+ *
+ * The third case is when the requested region lies between two extents
+ * within the same cluster:
+ *          |------------- cluster # N-------------|
+ * |----- ex -----|                  |---- ex_right ----|
+ *                  |------ requested region ------|
+ *                  |================|
+ *
+ * In each of the above cases, we need to set the map->m_pblk and
+ * map->m_len so it corresponds to the return the extent labelled as
+ * "|====|" from cluster #N, since it is already in use for data in
+ * cluster EXT4_B2C(sbi, map->m_lblk).	We will then return 1 to
+ * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
+ * as a new "allocated" block region.  Otherwise, we will return 0 and
+ * ext4_ext_map_blocks() will then allocate one or more new clusters
+ * by calling ext4_mb_new_blocks().
+ */
+static int get_implied_cluster_alloc(struct super_block *sb,
+				     struct ext4_map_blocks *map,
+				     struct ext4_extent *ex,
+				     struct ext4_ext_path *path)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
+	ext4_lblk_t ex_cluster_start, ex_cluster_end;
+	ext4_lblk_t rr_cluster_start;
+	ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
+	ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
+	unsigned short ee_len = ext4_ext_get_actual_len(ex);
+
+	/* The extent passed in that we are trying to match */
+	ex_cluster_start = EXT4_B2C(sbi, ee_block);
+	ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
+
+	/* The requested region passed into ext4_map_blocks() */
+	rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
+
+	if ((rr_cluster_start == ex_cluster_end) ||
+	    (rr_cluster_start == ex_cluster_start)) {
+		if (rr_cluster_start == ex_cluster_end)
+			ee_start += ee_len - 1;
+		map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
+		map->m_len = min(map->m_len,
+				 (unsigned) sbi->s_cluster_ratio - c_offset);
+		/*
+		 * Check for and handle this case:
+		 *
+		 *   |--------- cluster # N-------------|
+		 *		       |------- extent ----|
+		 *	   |--- requested region ---|
+		 *	   |===========|
+		 */
+
+		if (map->m_lblk < ee_block)
+			map->m_len = min(map->m_len, ee_block - map->m_lblk);
+
+		/*
+		 * Check for the case where there is already another allocated
+		 * block to the right of 'ex' but before the end of the cluster.
+		 *
+		 *          |------------- cluster # N-------------|
+		 * |----- ex -----|                  |---- ex_right ----|
+		 *                  |------ requested region ------|
+		 *                  |================|
+		 */
+		if (map->m_lblk > ee_block) {
+			ext4_lblk_t next = ext4_ext_next_allocated_block(path);
+			map->m_len = min(map->m_len, next - map->m_lblk);
+		}
+
+		trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
+		return 1;
+	}
+
+	trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
+	return 0;
+}
+
+
+/*
+ * Block allocation/map/preallocation routine for extents based files
+ *
+ *
+ * Need to be called with
+ * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
+ * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
+ *
+ * return > 0, number of blocks already mapped/allocated
+ *          if create == 0 and these are pre-allocated blocks
+ *          	buffer head is unmapped
+ *          otherwise blocks are mapped
+ *
+ * return = 0, if plain look up failed (blocks have not been allocated)
+ *          buffer head is unmapped
+ *
+ * return < 0, error case.
+ */
+int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
+			struct ext4_map_blocks *map, int flags)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent newex, *ex, ex2;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	ext4_fsblk_t newblock = 0, pblk;
+	int err = 0, depth, ret;
+	unsigned int allocated = 0, offset = 0;
+	unsigned int allocated_clusters = 0;
+	struct ext4_allocation_request ar;
+	ext4_lblk_t cluster_offset;
+
+	ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
+	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
+
+	/* find extent for this block */
+	path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
+	if (IS_ERR(path)) {
+		err = PTR_ERR(path);
+		path = NULL;
+		goto out;
+	}
+
+	depth = ext_depth(inode);
+
+	/*
+	 * consistent leaf must not be empty;
+	 * this situation is possible, though, _during_ tree modification;
+	 * this is why assert can't be put in ext4_find_extent()
+	 */
+	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
+		EXT4_ERROR_INODE(inode, "bad extent address "
+				 "lblock: %lu, depth: %d pblock %lld",
+				 (unsigned long) map->m_lblk, depth,
+				 path[depth].p_block);
+		err = -EFSCORRUPTED;
+		goto out;
+	}
+
+	ex = path[depth].p_ext;
+	if (ex) {
+		ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
+		ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
+		unsigned short ee_len;
+
+
+		/*
+		 * unwritten extents are treated as holes, except that
+		 * we split out initialized portions during a write.
+		 */
+		ee_len = ext4_ext_get_actual_len(ex);
+
+		trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
+
+		/* if found extent covers block, simply return it */
+		if (in_range(map->m_lblk, ee_block, ee_len)) {
+			newblock = map->m_lblk - ee_block + ee_start;
+			/* number of remaining blocks in the extent */
+			allocated = ee_len - (map->m_lblk - ee_block);
+			ext_debug(inode, "%u fit into %u:%d -> %llu\n",
+				  map->m_lblk, ee_block, ee_len, newblock);
+
+			/*
+			 * If the extent is initialized check whether the
+			 * caller wants to convert it to unwritten.
+			 */
+			if ((!ext4_ext_is_unwritten(ex)) &&
+			    (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
+				err = convert_initialized_extent(handle,
+					inode, map, &path, &allocated);
+				goto out;
+			} else if (!ext4_ext_is_unwritten(ex)) {
+				map->m_flags |= EXT4_MAP_MAPPED;
+				map->m_pblk = newblock;
+				if (allocated > map->m_len)
+					allocated = map->m_len;
+				map->m_len = allocated;
+				ext4_ext_show_leaf(inode, path);
+				goto out;
+			}
+
+			ret = ext4_ext_handle_unwritten_extents(
+				handle, inode, map, &path, flags,
+				allocated, newblock);
+			if (ret < 0)
+				err = ret;
+			else
+				allocated = ret;
+			goto out;
+		}
+	}
+
+	/*
+	 * requested block isn't allocated yet;
+	 * we couldn't try to create block if create flag is zero
+	 */
+	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
+		ext4_lblk_t hole_start, hole_len;
+
+		hole_start = map->m_lblk;
+		hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
+		/*
+		 * put just found gap into cache to speed up
+		 * subsequent requests
+		 */
+		ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
+
+		/* Update hole_len to reflect hole size after map->m_lblk */
+		if (hole_start != map->m_lblk)
+			hole_len -= map->m_lblk - hole_start;
+		map->m_pblk = 0;
+		map->m_len = min_t(unsigned int, map->m_len, hole_len);
+
+		goto out;
+	}
+
+	/*
+	 * Okay, we need to do block allocation.
+	 */
+	newex.ee_block = cpu_to_le32(map->m_lblk);
+	cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
+
+	/*
+	 * If we are doing bigalloc, check to see if the extent returned
+	 * by ext4_find_extent() implies a cluster we can use.
+	 */
+	if (cluster_offset && ex &&
+	    get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
+		ar.len = allocated = map->m_len;
+		newblock = map->m_pblk;
+		goto got_allocated_blocks;
+	}
+
+	/* find neighbour allocated blocks */
+	ar.lleft = map->m_lblk;
+	err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
+	if (err)
+		goto out;
+	ar.lright = map->m_lblk;
+	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
+	if (err < 0)
+		goto out;
+
+	/* Check if the extent after searching to the right implies a
+	 * cluster we can use. */
+	if ((sbi->s_cluster_ratio > 1) && err &&
+	    get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
+		ar.len = allocated = map->m_len;
+		newblock = map->m_pblk;
+		goto got_allocated_blocks;
+	}
+
+	/*
+	 * See if request is beyond maximum number of blocks we can have in
+	 * a single extent. For an initialized extent this limit is
+	 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
+	 * EXT_UNWRITTEN_MAX_LEN.
+	 */
+	if (map->m_len > EXT_INIT_MAX_LEN &&
+	    !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
+		map->m_len = EXT_INIT_MAX_LEN;
+	else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
+		 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
+		map->m_len = EXT_UNWRITTEN_MAX_LEN;
+
+	/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
+	newex.ee_len = cpu_to_le16(map->m_len);
+	err = ext4_ext_check_overlap(sbi, inode, &newex, path);
+	if (err)
+		allocated = ext4_ext_get_actual_len(&newex);
+	else
+		allocated = map->m_len;
+
+	/* allocate new block */
+	ar.inode = inode;
+	ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
+	ar.logical = map->m_lblk;
+	/*
+	 * We calculate the offset from the beginning of the cluster
+	 * for the logical block number, since when we allocate a
+	 * physical cluster, the physical block should start at the
+	 * same offset from the beginning of the cluster.  This is
+	 * needed so that future calls to get_implied_cluster_alloc()
+	 * work correctly.
+	 */
+	offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
+	ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
+	ar.goal -= offset;
+	ar.logical -= offset;
+	if (S_ISREG(inode->i_mode))
+		ar.flags = EXT4_MB_HINT_DATA;
+	else
+		/* disable in-core preallocation for non-regular files */
+		ar.flags = 0;
+	if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
+		ar.flags |= EXT4_MB_HINT_NOPREALLOC;
+	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+		ar.flags |= EXT4_MB_DELALLOC_RESERVED;
+	if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
+		ar.flags |= EXT4_MB_USE_RESERVED;
+	newblock = ext4_mb_new_blocks(handle, &ar, &err);
+	if (!newblock)
+		goto out;
+	allocated_clusters = ar.len;
+	ar.len = EXT4_C2B(sbi, ar.len) - offset;
+	ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
+		  ar.goal, newblock, ar.len, allocated);
+	if (ar.len > allocated)
+		ar.len = allocated;
+
+got_allocated_blocks:
+	/* try to insert new extent into found leaf and return */
+	pblk = newblock + offset;
+	ext4_ext_store_pblock(&newex, pblk);
+	newex.ee_len = cpu_to_le16(ar.len);
+	/* Mark unwritten */
+	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
+		ext4_ext_mark_unwritten(&newex);
+		map->m_flags |= EXT4_MAP_UNWRITTEN;
+	}
+
+	err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
+	if (err) {
+		if (allocated_clusters) {
+			int fb_flags = 0;
+
+			/*
+			 * free data blocks we just allocated.
+			 * not a good idea to call discard here directly,
+			 * but otherwise we'd need to call it every free().
+			 */
+			ext4_discard_preallocations(inode, 0);
+			if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+				fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
+			ext4_free_blocks(handle, inode, NULL, newblock,
+					 EXT4_C2B(sbi, allocated_clusters),
+					 fb_flags);
+		}
+		goto out;
+	}
+
+	/*
+	 * Reduce the reserved cluster count to reflect successful deferred
+	 * allocation of delayed allocated clusters or direct allocation of
+	 * clusters discovered to be delayed allocated.  Once allocated, a
+	 * cluster is not included in the reserved count.
+	 */
+	if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
+		if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
+			/*
+			 * When allocating delayed allocated clusters, simply
+			 * reduce the reserved cluster count and claim quota
+			 */
+			ext4_da_update_reserve_space(inode, allocated_clusters,
+							1);
+		} else {
+			ext4_lblk_t lblk, len;
+			unsigned int n;
+
+			/*
+			 * When allocating non-delayed allocated clusters
+			 * (from fallocate, filemap, DIO, or clusters
+			 * allocated when delalloc has been disabled by
+			 * ext4_nonda_switch), reduce the reserved cluster
+			 * count by the number of allocated clusters that
+			 * have previously been delayed allocated.  Quota
+			 * has been claimed by ext4_mb_new_blocks() above,
+			 * so release the quota reservations made for any
+			 * previously delayed allocated clusters.
+			 */
+			lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
+			len = allocated_clusters << sbi->s_cluster_bits;
+			n = ext4_es_delayed_clu(inode, lblk, len);
+			if (n > 0)
+				ext4_da_update_reserve_space(inode, (int) n, 0);
+		}
+	}
+
+	/*
+	 * Cache the extent and update transaction to commit on fdatasync only
+	 * when it is _not_ an unwritten extent.
+	 */
+	if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
+		ext4_update_inode_fsync_trans(handle, inode, 1);
+	else
+		ext4_update_inode_fsync_trans(handle, inode, 0);
+
+	map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
+	map->m_pblk = pblk;
+	map->m_len = ar.len;
+	allocated = map->m_len;
+	ext4_ext_show_leaf(inode, path);
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+
+	trace_ext4_ext_map_blocks_exit(inode, flags, map,
+				       err ? err : allocated);
+	return err ? err : allocated;
+}
+
+int ext4_ext_truncate(handle_t *handle, struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	ext4_lblk_t last_block;
+	int err = 0;
+
+	/*
+	 * TODO: optimization is possible here.
+	 * Probably we need not scan at all,
+	 * because page truncation is enough.
+	 */
+
+	/* we have to know where to truncate from in crash case */
+	EXT4_I(inode)->i_disksize = inode->i_size;
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (err)
+		return err;
+
+	last_block = (inode->i_size + sb->s_blocksize - 1)
+			>> EXT4_BLOCK_SIZE_BITS(sb);
+retry:
+	err = ext4_es_remove_extent(inode, last_block,
+				    EXT_MAX_BLOCKS - last_block);
+	if (err == -ENOMEM) {
+		cond_resched();
+		congestion_wait(BLK_RW_ASYNC, HZ/50);
+		goto retry;
+	}
+	if (err)
+		return err;
+retry_remove_space:
+	err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
+	if (err == -ENOMEM) {
+		cond_resched();
+		congestion_wait(BLK_RW_ASYNC, HZ/50);
+		goto retry_remove_space;
+	}
+	return err;
+}
+
+static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
+				  ext4_lblk_t len, loff_t new_size,
+				  int flags)
+{
+	struct inode *inode = file_inode(file);
+	handle_t *handle;
+	int ret = 0;
+	int ret2 = 0, ret3 = 0;
+	int retries = 0;
+	int depth = 0;
+	struct ext4_map_blocks map;
+	unsigned int credits;
+	loff_t epos;
+
+	BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
+	map.m_lblk = offset;
+	map.m_len = len;
+	/*
+	 * Don't normalize the request if it can fit in one extent so
+	 * that it doesn't get unnecessarily split into multiple
+	 * extents.
+	 */
+	if (len <= EXT_UNWRITTEN_MAX_LEN)
+		flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
+
+	/*
+	 * credits to insert 1 extent into extent tree
+	 */
+	credits = ext4_chunk_trans_blocks(inode, len);
+	depth = ext_depth(inode);
+
+retry:
+	while (ret >= 0 && len) {
+		/*
+		 * Recalculate credits when extent tree depth changes.
+		 */
+		if (depth != ext_depth(inode)) {
+			credits = ext4_chunk_trans_blocks(inode, len);
+			depth = ext_depth(inode);
+		}
+
+		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
+					    credits);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			break;
+		}
+		ret = ext4_map_blocks(handle, inode, &map, flags);
+		if (ret <= 0) {
+			ext4_debug("inode #%lu: block %u: len %u: "
+				   "ext4_ext_map_blocks returned %d",
+				   inode->i_ino, map.m_lblk,
+				   map.m_len, ret);
+			ext4_mark_inode_dirty(handle, inode);
+			ret2 = ext4_journal_stop(handle);
+			break;
+		}
+		map.m_lblk += ret;
+		map.m_len = len = len - ret;
+		epos = (loff_t)map.m_lblk << inode->i_blkbits;
+		inode->i_ctime = current_time(inode);
+		if (new_size) {
+			if (epos > new_size)
+				epos = new_size;
+			if (ext4_update_inode_size(inode, epos) & 0x1)
+				inode->i_mtime = inode->i_ctime;
+		}
+		ret2 = ext4_mark_inode_dirty(handle, inode);
+		ext4_update_inode_fsync_trans(handle, inode, 1);
+		ret3 = ext4_journal_stop(handle);
+		ret2 = ret3 ? ret3 : ret2;
+		if (unlikely(ret2))
+			break;
+	}
+	if (ret == -ENOSPC &&
+			ext4_should_retry_alloc(inode->i_sb, &retries)) {
+		ret = 0;
+		goto retry;
+	}
+
+	return ret > 0 ? ret2 : ret;
+}
+
+static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
+
+static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
+
+static long ext4_zero_range(struct file *file, loff_t offset,
+			    loff_t len, int mode)
+{
+	struct inode *inode = file_inode(file);
+	handle_t *handle = NULL;
+	unsigned int max_blocks;
+	loff_t new_size = 0;
+	int ret = 0;
+	int flags;
+	int credits;
+	int partial_begin, partial_end;
+	loff_t start, end;
+	ext4_lblk_t lblk;
+	unsigned int blkbits = inode->i_blkbits;
+
+	trace_ext4_zero_range(inode, offset, len, mode);
+
+	/* Call ext4_force_commit to flush all data in case of data=journal. */
+	if (ext4_should_journal_data(inode)) {
+		ret = ext4_force_commit(inode->i_sb);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * Round up offset. This is not fallocate, we need to zero out
+	 * blocks, so convert interior block aligned part of the range to
+	 * unwritten and possibly manually zero out unaligned parts of the
+	 * range.
+	 */
+	start = round_up(offset, 1 << blkbits);
+	end = round_down((offset + len), 1 << blkbits);
+
+	if (start < offset || end > offset + len)
+		return -EINVAL;
+	partial_begin = offset & ((1 << blkbits) - 1);
+	partial_end = (offset + len) & ((1 << blkbits) - 1);
+
+	lblk = start >> blkbits;
+	max_blocks = (end >> blkbits);
+	if (max_blocks < lblk)
+		max_blocks = 0;
+	else
+		max_blocks -= lblk;
+
+	inode_lock(inode);
+
+	/*
+	 * Indirect files do not support unwritten extents
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		ret = -EOPNOTSUPP;
+		goto out_mutex;
+	}
+
+	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+	    (offset + len > inode->i_size ||
+	     offset + len > EXT4_I(inode)->i_disksize)) {
+		new_size = offset + len;
+		ret = inode_newsize_ok(inode, new_size);
+		if (ret)
+			goto out_mutex;
+	}
+
+	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
+
+	/* Wait all existing dio workers, newcomers will block on i_mutex */
+	inode_dio_wait(inode);
+
+	ret = file_modified(file);
+	if (ret)
+		goto out_mutex;
+
+	/* Preallocate the range including the unaligned edges */
+	if (partial_begin || partial_end) {
+		ret = ext4_alloc_file_blocks(file,
+				round_down(offset, 1 << blkbits) >> blkbits,
+				(round_up((offset + len), 1 << blkbits) -
+				 round_down(offset, 1 << blkbits)) >> blkbits,
+				new_size, flags);
+		if (ret)
+			goto out_mutex;
+
+	}
+
+	/* Zero range excluding the unaligned edges */
+	if (max_blocks > 0) {
+		flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
+			  EXT4_EX_NOCACHE);
+
+		/*
+		 * Prevent page faults from reinstantiating pages we have
+		 * released from page cache.
+		 */
+		down_write(&EXT4_I(inode)->i_mmap_sem);
+
+		ret = ext4_break_layouts(inode);
+		if (ret) {
+			up_write(&EXT4_I(inode)->i_mmap_sem);
+			goto out_mutex;
+		}
+
+		ret = ext4_update_disksize_before_punch(inode, offset, len);
+		if (ret) {
+			up_write(&EXT4_I(inode)->i_mmap_sem);
+			goto out_mutex;
+		}
+		/* Now release the pages and zero block aligned part of pages */
+		truncate_pagecache_range(inode, start, end - 1);
+		inode->i_mtime = inode->i_ctime = current_time(inode);
+
+		ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
+					     flags);
+		up_write(&EXT4_I(inode)->i_mmap_sem);
+		if (ret)
+			goto out_mutex;
+	}
+	if (!partial_begin && !partial_end)
+		goto out_mutex;
+
+	/*
+	 * In worst case we have to writeout two nonadjacent unwritten
+	 * blocks and update the inode
+	 */
+	credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
+	if (ext4_should_journal_data(inode))
+		credits += 2;
+	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		ext4_std_error(inode->i_sb, ret);
+		goto out_mutex;
+	}
+
+	inode->i_mtime = inode->i_ctime = current_time(inode);
+	if (new_size)
+		ext4_update_inode_size(inode, new_size);
+	ret = ext4_mark_inode_dirty(handle, inode);
+	if (unlikely(ret))
+		goto out_handle;
+	/* Zero out partial block at the edges of the range */
+	ret = ext4_zero_partial_blocks(handle, inode, offset, len);
+	if (ret >= 0)
+		ext4_update_inode_fsync_trans(handle, inode, 1);
+
+	if (file->f_flags & O_SYNC)
+		ext4_handle_sync(handle);
+
+out_handle:
+	ext4_journal_stop(handle);
+out_mutex:
+	inode_unlock(inode);
+	return ret;
+}
+
+/*
+ * preallocate space for a file. This implements ext4's fallocate file
+ * operation, which gets called from sys_fallocate system call.
+ * For block-mapped files, posix_fallocate should fall back to the method
+ * of writing zeroes to the required new blocks (the same behavior which is
+ * expected for file systems which do not support fallocate() system call).
+ */
+long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
+{
+	struct inode *inode = file_inode(file);
+	loff_t new_size = 0;
+	unsigned int max_blocks;
+	int ret = 0;
+	int flags;
+	ext4_lblk_t lblk;
+	unsigned int blkbits = inode->i_blkbits;
+
+	/*
+	 * Encrypted inodes can't handle collapse range or insert
+	 * range since we would need to re-encrypt blocks with a
+	 * different IV or XTS tweak (which are based on the logical
+	 * block number).
+	 */
+	if (IS_ENCRYPTED(inode) &&
+	    (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
+		return -EOPNOTSUPP;
+
+	/* Return error if mode is not supported */
+	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
+		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
+		     FALLOC_FL_INSERT_RANGE))
+		return -EOPNOTSUPP;
+
+	inode_lock(inode);
+	ret = ext4_convert_inline_data(inode);
+	inode_unlock(inode);
+	if (ret)
+		goto exit;
+
+	if (mode & FALLOC_FL_PUNCH_HOLE) {
+		ret = ext4_punch_hole(file, offset, len);
+		goto exit;
+	}
+
+	if (mode & FALLOC_FL_COLLAPSE_RANGE) {
+		ret = ext4_collapse_range(file, offset, len);
+		goto exit;
+	}
+
+	if (mode & FALLOC_FL_INSERT_RANGE) {
+		ret = ext4_insert_range(file, offset, len);
+		goto exit;
+	}
+
+	if (mode & FALLOC_FL_ZERO_RANGE) {
+		ret = ext4_zero_range(file, offset, len, mode);
+		goto exit;
+	}
+	trace_ext4_fallocate_enter(inode, offset, len, mode);
+	lblk = offset >> blkbits;
+
+	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
+	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
+
+	inode_lock(inode);
+
+	/*
+	 * We only support preallocation for extent-based files only
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+	    (offset + len > inode->i_size ||
+	     offset + len > EXT4_I(inode)->i_disksize)) {
+		new_size = offset + len;
+		ret = inode_newsize_ok(inode, new_size);
+		if (ret)
+			goto out;
+	}
+
+	/* Wait all existing dio workers, newcomers will block on i_mutex */
+	inode_dio_wait(inode);
+
+	ret = file_modified(file);
+	if (ret)
+		goto out;
+
+	ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
+	if (ret)
+		goto out;
+
+	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
+		ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
+					EXT4_I(inode)->i_sync_tid);
+	}
+out:
+	inode_unlock(inode);
+	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
+exit:
+	return ret;
+}
+
+/*
+ * This function convert a range of blocks to written extents
+ * The caller of this function will pass the start offset and the size.
+ * all unwritten extents within this range will be converted to
+ * written extents.
+ *
+ * This function is called from the direct IO end io call back
+ * function, to convert the fallocated extents after IO is completed.
+ * Returns 0 on success.
+ */
+int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
+				   loff_t offset, ssize_t len)
+{
+	unsigned int max_blocks;
+	int ret = 0, ret2 = 0, ret3 = 0;
+	struct ext4_map_blocks map;
+	unsigned int blkbits = inode->i_blkbits;
+	unsigned int credits = 0;
+
+	map.m_lblk = offset >> blkbits;
+	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
+
+	if (!handle) {
+		/*
+		 * credits to insert 1 extent into extent tree
+		 */
+		credits = ext4_chunk_trans_blocks(inode, max_blocks);
+	}
+	while (ret >= 0 && ret < max_blocks) {
+		map.m_lblk += ret;
+		map.m_len = (max_blocks -= ret);
+		if (credits) {
+			handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
+						    credits);
+			if (IS_ERR(handle)) {
+				ret = PTR_ERR(handle);
+				break;
+			}
+		}
+		ret = ext4_map_blocks(handle, inode, &map,
+				      EXT4_GET_BLOCKS_IO_CONVERT_EXT);
+		if (ret <= 0)
+			ext4_warning(inode->i_sb,
+				     "inode #%lu: block %u: len %u: "
+				     "ext4_ext_map_blocks returned %d",
+				     inode->i_ino, map.m_lblk,
+				     map.m_len, ret);
+		ret2 = ext4_mark_inode_dirty(handle, inode);
+		if (credits) {
+			ret3 = ext4_journal_stop(handle);
+			if (unlikely(ret3))
+				ret2 = ret3;
+		}
+
+		if (ret <= 0 || ret2)
+			break;
+	}
+	return ret > 0 ? ret2 : ret;
+}
+
+int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
+{
+	int ret = 0, err = 0;
+	struct ext4_io_end_vec *io_end_vec;
+
+	/*
+	 * This is somewhat ugly but the idea is clear: When transaction is
+	 * reserved, everything goes into it. Otherwise we rather start several
+	 * smaller transactions for conversion of each extent separately.
+	 */
+	if (handle) {
+		handle = ext4_journal_start_reserved(handle,
+						     EXT4_HT_EXT_CONVERT);
+		if (IS_ERR(handle))
+			return PTR_ERR(handle);
+	}
+
+	list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
+		ret = ext4_convert_unwritten_extents(handle, io_end->inode,
+						     io_end_vec->offset,
+						     io_end_vec->size);
+		if (ret)
+			break;
+	}
+
+	if (handle)
+		err = ext4_journal_stop(handle);
+
+	return ret < 0 ? ret : err;
+}
+
+static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
+{
+	__u64 physical = 0;
+	__u64 length = 0;
+	int blockbits = inode->i_sb->s_blocksize_bits;
+	int error = 0;
+	u16 iomap_type;
+
+	/* in-inode? */
+	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
+		struct ext4_iloc iloc;
+		int offset;	/* offset of xattr in inode */
+
+		error = ext4_get_inode_loc(inode, &iloc);
+		if (error)
+			return error;
+		physical = (__u64)iloc.bh->b_blocknr << blockbits;
+		offset = EXT4_GOOD_OLD_INODE_SIZE +
+				EXT4_I(inode)->i_extra_isize;
+		physical += offset;
+		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
+		brelse(iloc.bh);
+		iomap_type = IOMAP_INLINE;
+	} else if (EXT4_I(inode)->i_file_acl) { /* external block */
+		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
+		length = inode->i_sb->s_blocksize;
+		iomap_type = IOMAP_MAPPED;
+	} else {
+		/* no in-inode or external block for xattr, so return -ENOENT */
+		error = -ENOENT;
+		goto out;
+	}
+
+	iomap->addr = physical;
+	iomap->offset = 0;
+	iomap->length = length;
+	iomap->type = iomap_type;
+	iomap->flags = 0;
+out:
+	return error;
+}
+
+static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
+				  loff_t length, unsigned flags,
+				  struct iomap *iomap, struct iomap *srcmap)
+{
+	int error;
+
+	error = ext4_iomap_xattr_fiemap(inode, iomap);
+	if (error == 0 && (offset >= iomap->length))
+		error = -ENOENT;
+	return error;
+}
+
+static const struct iomap_ops ext4_iomap_xattr_ops = {
+	.iomap_begin		= ext4_iomap_xattr_begin,
+};
+
+static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
+{
+	u64 maxbytes;
+
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		maxbytes = inode->i_sb->s_maxbytes;
+	else
+		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
+
+	if (*len == 0)
+		return -EINVAL;
+	if (start > maxbytes)
+		return -EFBIG;
+
+	/*
+	 * Shrink request scope to what the fs can actually handle.
+	 */
+	if (*len > maxbytes || (maxbytes - *len) < start)
+		*len = maxbytes - start;
+	return 0;
+}
+
+int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+		u64 start, u64 len)
+{
+	int error = 0;
+
+	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
+		error = ext4_ext_precache(inode);
+		if (error)
+			return error;
+		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
+	}
+
+	/*
+	 * For bitmap files the maximum size limit could be smaller than
+	 * s_maxbytes, so check len here manually instead of just relying on the
+	 * generic check.
+	 */
+	error = ext4_fiemap_check_ranges(inode, start, &len);
+	if (error)
+		return error;
+
+	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
+		fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
+		return iomap_fiemap(inode, fieinfo, start, len,
+				    &ext4_iomap_xattr_ops);
+	}
+
+	return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
+}
+
+int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
+		      __u64 start, __u64 len)
+{
+	ext4_lblk_t start_blk, len_blks;
+	__u64 last_blk;
+	int error = 0;
+
+	if (ext4_has_inline_data(inode)) {
+		int has_inline;
+
+		down_read(&EXT4_I(inode)->xattr_sem);
+		has_inline = ext4_has_inline_data(inode);
+		up_read(&EXT4_I(inode)->xattr_sem);
+		if (has_inline)
+			return 0;
+	}
+
+	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
+		error = ext4_ext_precache(inode);
+		if (error)
+			return error;
+		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
+	}
+
+	error = fiemap_prep(inode, fieinfo, start, &len, 0);
+	if (error)
+		return error;
+
+	error = ext4_fiemap_check_ranges(inode, start, &len);
+	if (error)
+		return error;
+
+	start_blk = start >> inode->i_sb->s_blocksize_bits;
+	last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
+	if (last_blk >= EXT_MAX_BLOCKS)
+		last_blk = EXT_MAX_BLOCKS-1;
+	len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
+
+	/*
+	 * Walk the extent tree gathering extent information
+	 * and pushing extents back to the user.
+	 */
+	return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
+}
+
+/*
+ * ext4_ext_shift_path_extents:
+ * Shift the extents of a path structure lying between path[depth].p_ext
+ * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
+ * if it is right shift or left shift operation.
+ */
+static int
+ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
+			    struct inode *inode, handle_t *handle,
+			    enum SHIFT_DIRECTION SHIFT)
+{
+	int depth, err = 0;
+	struct ext4_extent *ex_start, *ex_last;
+	bool update = false;
+	int credits, restart_credits;
+	depth = path->p_depth;
+
+	while (depth >= 0) {
+		if (depth == path->p_depth) {
+			ex_start = path[depth].p_ext;
+			if (!ex_start)
+				return -EFSCORRUPTED;
+
+			ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
+			/* leaf + sb + inode */
+			credits = 3;
+			if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
+				update = true;
+				/* extent tree + sb + inode */
+				credits = depth + 2;
+			}
+
+			restart_credits = ext4_writepage_trans_blocks(inode);
+			err = ext4_datasem_ensure_credits(handle, inode, credits,
+					restart_credits, 0);
+			if (err) {
+				if (err > 0)
+					err = -EAGAIN;
+				goto out;
+			}
+
+			err = ext4_ext_get_access(handle, inode, path + depth);
+			if (err)
+				goto out;
+
+			while (ex_start <= ex_last) {
+				if (SHIFT == SHIFT_LEFT) {
+					le32_add_cpu(&ex_start->ee_block,
+						-shift);
+					/* Try to merge to the left. */
+					if ((ex_start >
+					    EXT_FIRST_EXTENT(path[depth].p_hdr))
+					    &&
+					    ext4_ext_try_to_merge_right(inode,
+					    path, ex_start - 1))
+						ex_last--;
+					else
+						ex_start++;
+				} else {
+					le32_add_cpu(&ex_last->ee_block, shift);
+					ext4_ext_try_to_merge_right(inode, path,
+						ex_last);
+					ex_last--;
+				}
+			}
+			err = ext4_ext_dirty(handle, inode, path + depth);
+			if (err)
+				goto out;
+
+			if (--depth < 0 || !update)
+				break;
+		}
+
+		/* Update index too */
+		err = ext4_ext_get_access(handle, inode, path + depth);
+		if (err)
+			goto out;
+
+		if (SHIFT == SHIFT_LEFT)
+			le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
+		else
+			le32_add_cpu(&path[depth].p_idx->ei_block, shift);
+		err = ext4_ext_dirty(handle, inode, path + depth);
+		if (err)
+			goto out;
+
+		/* we are done if current index is not a starting index */
+		if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
+			break;
+
+		depth--;
+	}
+
+out:
+	return err;
+}
+
+/*
+ * ext4_ext_shift_extents:
+ * All the extents which lies in the range from @start to the last allocated
+ * block for the @inode are shifted either towards left or right (depending
+ * upon @SHIFT) by @shift blocks.
+ * On success, 0 is returned, error otherwise.
+ */
+static int
+ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
+		       ext4_lblk_t start, ext4_lblk_t shift,
+		       enum SHIFT_DIRECTION SHIFT)
+{
+	struct ext4_ext_path *path;
+	int ret = 0, depth;
+	struct ext4_extent *extent;
+	ext4_lblk_t stop, *iterator, ex_start, ex_end;
+	ext4_lblk_t tmp = EXT_MAX_BLOCKS;
+
+	/* Let path point to the last extent */
+	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
+				EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	depth = path->p_depth;
+	extent = path[depth].p_ext;
+	if (!extent)
+		goto out;
+
+	stop = le32_to_cpu(extent->ee_block);
+
+       /*
+	* For left shifts, make sure the hole on the left is big enough to
+	* accommodate the shift.  For right shifts, make sure the last extent
+	* won't be shifted beyond EXT_MAX_BLOCKS.
+	*/
+	if (SHIFT == SHIFT_LEFT) {
+		path = ext4_find_extent(inode, start - 1, &path,
+					EXT4_EX_NOCACHE);
+		if (IS_ERR(path))
+			return PTR_ERR(path);
+		depth = path->p_depth;
+		extent =  path[depth].p_ext;
+		if (extent) {
+			ex_start = le32_to_cpu(extent->ee_block);
+			ex_end = le32_to_cpu(extent->ee_block) +
+				ext4_ext_get_actual_len(extent);
+		} else {
+			ex_start = 0;
+			ex_end = 0;
+		}
+
+		if ((start == ex_start && shift > ex_start) ||
+		    (shift > start - ex_end)) {
+			ret = -EINVAL;
+			goto out;
+		}
+	} else {
+		if (shift > EXT_MAX_BLOCKS -
+		    (stop + ext4_ext_get_actual_len(extent))) {
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	/*
+	 * In case of left shift, iterator points to start and it is increased
+	 * till we reach stop. In case of right shift, iterator points to stop
+	 * and it is decreased till we reach start.
+	 */
+again:
+	ret = 0;
+	if (SHIFT == SHIFT_LEFT)
+		iterator = &start;
+	else
+		iterator = &stop;
+
+	if (tmp != EXT_MAX_BLOCKS)
+		*iterator = tmp;
+
+	/*
+	 * Its safe to start updating extents.  Start and stop are unsigned, so
+	 * in case of right shift if extent with 0 block is reached, iterator
+	 * becomes NULL to indicate the end of the loop.
+	 */
+	while (iterator && start <= stop) {
+		path = ext4_find_extent(inode, *iterator, &path,
+					EXT4_EX_NOCACHE);
+		if (IS_ERR(path))
+			return PTR_ERR(path);
+		depth = path->p_depth;
+		extent = path[depth].p_ext;
+		if (!extent) {
+			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
+					 (unsigned long) *iterator);
+			return -EFSCORRUPTED;
+		}
+		if (SHIFT == SHIFT_LEFT && *iterator >
+		    le32_to_cpu(extent->ee_block)) {
+			/* Hole, move to the next extent */
+			if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
+				path[depth].p_ext++;
+			} else {
+				*iterator = ext4_ext_next_allocated_block(path);
+				continue;
+			}
+		}
+
+		tmp = *iterator;
+		if (SHIFT == SHIFT_LEFT) {
+			extent = EXT_LAST_EXTENT(path[depth].p_hdr);
+			*iterator = le32_to_cpu(extent->ee_block) +
+					ext4_ext_get_actual_len(extent);
+		} else {
+			extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
+			if (le32_to_cpu(extent->ee_block) > start)
+				*iterator = le32_to_cpu(extent->ee_block) - 1;
+			else if (le32_to_cpu(extent->ee_block) == start)
+				iterator = NULL;
+			else {
+				extent = EXT_LAST_EXTENT(path[depth].p_hdr);
+				while (le32_to_cpu(extent->ee_block) >= start)
+					extent--;
+
+				if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))
+					break;
+
+				extent++;
+				iterator = NULL;
+			}
+			path[depth].p_ext = extent;
+		}
+		ret = ext4_ext_shift_path_extents(path, shift, inode,
+				handle, SHIFT);
+		/* iterator can be NULL which means we should break */
+		if (ret == -EAGAIN)
+			goto again;
+		if (ret)
+			break;
+	}
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	return ret;
+}
+
+/*
+ * ext4_collapse_range:
+ * This implements the fallocate's collapse range functionality for ext4
+ * Returns: 0 and non-zero on error.
+ */
+static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
+{
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	ext4_lblk_t punch_start, punch_stop;
+	handle_t *handle;
+	unsigned int credits;
+	loff_t new_size, ioffset;
+	int ret;
+
+	/*
+	 * We need to test this early because xfstests assumes that a
+	 * collapse range of (0, 1) will return EOPNOTSUPP if the file
+	 * system does not support collapse range.
+	 */
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		return -EOPNOTSUPP;
+
+	/* Collapse range works only on fs cluster size aligned regions. */
+	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
+		return -EINVAL;
+
+	trace_ext4_collapse_range(inode, offset, len);
+
+	punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
+	punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
+
+	/* Call ext4_force_commit to flush all data in case of data=journal. */
+	if (ext4_should_journal_data(inode)) {
+		ret = ext4_force_commit(inode->i_sb);
+		if (ret)
+			return ret;
+	}
+
+	inode_lock(inode);
+	/*
+	 * There is no need to overlap collapse range with EOF, in which case
+	 * it is effectively a truncate operation
+	 */
+	if (offset + len >= inode->i_size) {
+		ret = -EINVAL;
+		goto out_mutex;
+	}
+
+	/* Currently just for extent based files */
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		ret = -EOPNOTSUPP;
+		goto out_mutex;
+	}
+
+	/* Wait for existing dio to complete */
+	inode_dio_wait(inode);
+
+	ret = file_modified(file);
+	if (ret)
+		goto out_mutex;
+
+	/*
+	 * Prevent page faults from reinstantiating pages we have released from
+	 * page cache.
+	 */
+	down_write(&EXT4_I(inode)->i_mmap_sem);
+
+	ret = ext4_break_layouts(inode);
+	if (ret)
+		goto out_mmap;
+
+	/*
+	 * Need to round down offset to be aligned with page size boundary
+	 * for page size > block size.
+	 */
+	ioffset = round_down(offset, PAGE_SIZE);
+	/*
+	 * Write tail of the last page before removed range since it will get
+	 * removed from the page cache below.
+	 */
+	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
+	if (ret)
+		goto out_mmap;
+	/*
+	 * Write data that will be shifted to preserve them when discarding
+	 * page cache below. We are also protected from pages becoming dirty
+	 * by i_mmap_sem.
+	 */
+	ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
+					   LLONG_MAX);
+	if (ret)
+		goto out_mmap;
+	truncate_pagecache(inode, ioffset);
+
+	credits = ext4_writepage_trans_blocks(inode);
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out_mmap;
+	}
+	ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	ext4_discard_preallocations(inode, 0);
+
+	ret = ext4_es_remove_extent(inode, punch_start,
+				    EXT_MAX_BLOCKS - punch_start);
+	if (ret) {
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto out_stop;
+	}
+
+	ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
+	if (ret) {
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto out_stop;
+	}
+	ext4_discard_preallocations(inode, 0);
+
+	ret = ext4_ext_shift_extents(inode, handle, punch_stop,
+				     punch_stop - punch_start, SHIFT_LEFT);
+	if (ret) {
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto out_stop;
+	}
+
+	new_size = inode->i_size - len;
+	i_size_write(inode, new_size);
+	EXT4_I(inode)->i_disksize = new_size;
+
+	up_write(&EXT4_I(inode)->i_data_sem);
+	if (IS_SYNC(inode))
+		ext4_handle_sync(handle);
+	inode->i_mtime = inode->i_ctime = current_time(inode);
+	ret = ext4_mark_inode_dirty(handle, inode);
+	ext4_update_inode_fsync_trans(handle, inode, 1);
+
+out_stop:
+	ext4_journal_stop(handle);
+	ext4_fc_stop_ineligible(sb);
+out_mmap:
+	up_write(&EXT4_I(inode)->i_mmap_sem);
+out_mutex:
+	inode_unlock(inode);
+	return ret;
+}
+
+/*
+ * ext4_insert_range:
+ * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
+ * The data blocks starting from @offset to the EOF are shifted by @len
+ * towards right to create a hole in the @inode. Inode size is increased
+ * by len bytes.
+ * Returns 0 on success, error otherwise.
+ */
+static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
+{
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	handle_t *handle;
+	struct ext4_ext_path *path;
+	struct ext4_extent *extent;
+	ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
+	unsigned int credits, ee_len;
+	int ret = 0, depth, split_flag = 0;
+	loff_t ioffset;
+
+	/*
+	 * We need to test this early because xfstests assumes that an
+	 * insert range of (0, 1) will return EOPNOTSUPP if the file
+	 * system does not support insert range.
+	 */
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		return -EOPNOTSUPP;
+
+	/* Insert range works only on fs cluster size aligned regions. */
+	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
+		return -EINVAL;
+
+	trace_ext4_insert_range(inode, offset, len);
+
+	offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
+	len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
+
+	/* Call ext4_force_commit to flush all data in case of data=journal */
+	if (ext4_should_journal_data(inode)) {
+		ret = ext4_force_commit(inode->i_sb);
+		if (ret)
+			return ret;
+	}
+
+	inode_lock(inode);
+	/* Currently just for extent based files */
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		ret = -EOPNOTSUPP;
+		goto out_mutex;
+	}
+
+	/* Check whether the maximum file size would be exceeded */
+	if (len > inode->i_sb->s_maxbytes - inode->i_size) {
+		ret = -EFBIG;
+		goto out_mutex;
+	}
+
+	/* Offset must be less than i_size */
+	if (offset >= inode->i_size) {
+		ret = -EINVAL;
+		goto out_mutex;
+	}
+
+	/* Wait for existing dio to complete */
+	inode_dio_wait(inode);
+
+	ret = file_modified(file);
+	if (ret)
+		goto out_mutex;
+
+	/*
+	 * Prevent page faults from reinstantiating pages we have released from
+	 * page cache.
+	 */
+	down_write(&EXT4_I(inode)->i_mmap_sem);
+
+	ret = ext4_break_layouts(inode);
+	if (ret)
+		goto out_mmap;
+
+	/*
+	 * Need to round down to align start offset to page size boundary
+	 * for page size > block size.
+	 */
+	ioffset = round_down(offset, PAGE_SIZE);
+	/* Write out all dirty pages */
+	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
+			LLONG_MAX);
+	if (ret)
+		goto out_mmap;
+	truncate_pagecache(inode, ioffset);
+
+	credits = ext4_writepage_trans_blocks(inode);
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out_mmap;
+	}
+	ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
+
+	/* Expand file to avoid data loss if there is error while shifting */
+	inode->i_size += len;
+	EXT4_I(inode)->i_disksize += len;
+	inode->i_mtime = inode->i_ctime = current_time(inode);
+	ret = ext4_mark_inode_dirty(handle, inode);
+	if (ret)
+		goto out_stop;
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	ext4_discard_preallocations(inode, 0);
+
+	path = ext4_find_extent(inode, offset_lblk, NULL, 0);
+	if (IS_ERR(path)) {
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto out_stop;
+	}
+
+	depth = ext_depth(inode);
+	extent = path[depth].p_ext;
+	if (extent) {
+		ee_start_lblk = le32_to_cpu(extent->ee_block);
+		ee_len = ext4_ext_get_actual_len(extent);
+
+		/*
+		 * If offset_lblk is not the starting block of extent, split
+		 * the extent @offset_lblk
+		 */
+		if ((offset_lblk > ee_start_lblk) &&
+				(offset_lblk < (ee_start_lblk + ee_len))) {
+			if (ext4_ext_is_unwritten(extent))
+				split_flag = EXT4_EXT_MARK_UNWRIT1 |
+					EXT4_EXT_MARK_UNWRIT2;
+			ret = ext4_split_extent_at(handle, inode, &path,
+					offset_lblk, split_flag,
+					EXT4_EX_NOCACHE |
+					EXT4_GET_BLOCKS_PRE_IO |
+					EXT4_GET_BLOCKS_METADATA_NOFAIL);
+		}
+
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		if (ret < 0) {
+			up_write(&EXT4_I(inode)->i_data_sem);
+			goto out_stop;
+		}
+	} else {
+		ext4_ext_drop_refs(path);
+		kfree(path);
+	}
+
+	ret = ext4_es_remove_extent(inode, offset_lblk,
+			EXT_MAX_BLOCKS - offset_lblk);
+	if (ret) {
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto out_stop;
+	}
+
+	/*
+	 * if offset_lblk lies in a hole which is at start of file, use
+	 * ee_start_lblk to shift extents
+	 */
+	ret = ext4_ext_shift_extents(inode, handle,
+		ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
+		len_lblk, SHIFT_RIGHT);
+
+	up_write(&EXT4_I(inode)->i_data_sem);
+	if (IS_SYNC(inode))
+		ext4_handle_sync(handle);
+	if (ret >= 0)
+		ext4_update_inode_fsync_trans(handle, inode, 1);
+
+out_stop:
+	ext4_journal_stop(handle);
+	ext4_fc_stop_ineligible(sb);
+out_mmap:
+	up_write(&EXT4_I(inode)->i_mmap_sem);
+out_mutex:
+	inode_unlock(inode);
+	return ret;
+}
+
+/**
+ * ext4_swap_extents() - Swap extents between two inodes
+ * @handle: handle for this transaction
+ * @inode1:	First inode
+ * @inode2:	Second inode
+ * @lblk1:	Start block for first inode
+ * @lblk2:	Start block for second inode
+ * @count:	Number of blocks to swap
+ * @unwritten: Mark second inode's extents as unwritten after swap
+ * @erp:	Pointer to save error value
+ *
+ * This helper routine does exactly what is promise "swap extents". All other
+ * stuff such as page-cache locking consistency, bh mapping consistency or
+ * extent's data copying must be performed by caller.
+ * Locking:
+ * 		i_mutex is held for both inodes
+ * 		i_data_sem is locked for write for both inodes
+ * Assumptions:
+ *		All pages from requested range are locked for both inodes
+ */
+int
+ext4_swap_extents(handle_t *handle, struct inode *inode1,
+		  struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
+		  ext4_lblk_t count, int unwritten, int *erp)
+{
+	struct ext4_ext_path *path1 = NULL;
+	struct ext4_ext_path *path2 = NULL;
+	int replaced_count = 0;
+
+	BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
+	BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
+	BUG_ON(!inode_is_locked(inode1));
+	BUG_ON(!inode_is_locked(inode2));
+
+	*erp = ext4_es_remove_extent(inode1, lblk1, count);
+	if (unlikely(*erp))
+		return 0;
+	*erp = ext4_es_remove_extent(inode2, lblk2, count);
+	if (unlikely(*erp))
+		return 0;
+
+	while (count) {
+		struct ext4_extent *ex1, *ex2, tmp_ex;
+		ext4_lblk_t e1_blk, e2_blk;
+		int e1_len, e2_len, len;
+		int split = 0;
+
+		path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
+		if (IS_ERR(path1)) {
+			*erp = PTR_ERR(path1);
+			path1 = NULL;
+		finish:
+			count = 0;
+			goto repeat;
+		}
+		path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
+		if (IS_ERR(path2)) {
+			*erp = PTR_ERR(path2);
+			path2 = NULL;
+			goto finish;
+		}
+		ex1 = path1[path1->p_depth].p_ext;
+		ex2 = path2[path2->p_depth].p_ext;
+		/* Do we have something to swap ? */
+		if (unlikely(!ex2 || !ex1))
+			goto finish;
+
+		e1_blk = le32_to_cpu(ex1->ee_block);
+		e2_blk = le32_to_cpu(ex2->ee_block);
+		e1_len = ext4_ext_get_actual_len(ex1);
+		e2_len = ext4_ext_get_actual_len(ex2);
+
+		/* Hole handling */
+		if (!in_range(lblk1, e1_blk, e1_len) ||
+		    !in_range(lblk2, e2_blk, e2_len)) {
+			ext4_lblk_t next1, next2;
+
+			/* if hole after extent, then go to next extent */
+			next1 = ext4_ext_next_allocated_block(path1);
+			next2 = ext4_ext_next_allocated_block(path2);
+			/* If hole before extent, then shift to that extent */
+			if (e1_blk > lblk1)
+				next1 = e1_blk;
+			if (e2_blk > lblk2)
+				next2 = e2_blk;
+			/* Do we have something to swap */
+			if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
+				goto finish;
+			/* Move to the rightest boundary */
+			len = next1 - lblk1;
+			if (len < next2 - lblk2)
+				len = next2 - lblk2;
+			if (len > count)
+				len = count;
+			lblk1 += len;
+			lblk2 += len;
+			count -= len;
+			goto repeat;
+		}
+
+		/* Prepare left boundary */
+		if (e1_blk < lblk1) {
+			split = 1;
+			*erp = ext4_force_split_extent_at(handle, inode1,
+						&path1, lblk1, 0);
+			if (unlikely(*erp))
+				goto finish;
+		}
+		if (e2_blk < lblk2) {
+			split = 1;
+			*erp = ext4_force_split_extent_at(handle, inode2,
+						&path2,  lblk2, 0);
+			if (unlikely(*erp))
+				goto finish;
+		}
+		/* ext4_split_extent_at() may result in leaf extent split,
+		 * path must to be revalidated. */
+		if (split)
+			goto repeat;
+
+		/* Prepare right boundary */
+		len = count;
+		if (len > e1_blk + e1_len - lblk1)
+			len = e1_blk + e1_len - lblk1;
+		if (len > e2_blk + e2_len - lblk2)
+			len = e2_blk + e2_len - lblk2;
+
+		if (len != e1_len) {
+			split = 1;
+			*erp = ext4_force_split_extent_at(handle, inode1,
+						&path1, lblk1 + len, 0);
+			if (unlikely(*erp))
+				goto finish;
+		}
+		if (len != e2_len) {
+			split = 1;
+			*erp = ext4_force_split_extent_at(handle, inode2,
+						&path2, lblk2 + len, 0);
+			if (*erp)
+				goto finish;
+		}
+		/* ext4_split_extent_at() may result in leaf extent split,
+		 * path must to be revalidated. */
+		if (split)
+			goto repeat;
+
+		BUG_ON(e2_len != e1_len);
+		*erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
+		if (unlikely(*erp))
+			goto finish;
+		*erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
+		if (unlikely(*erp))
+			goto finish;
+
+		/* Both extents are fully inside boundaries. Swap it now */
+		tmp_ex = *ex1;
+		ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
+		ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
+		ex1->ee_len = cpu_to_le16(e2_len);
+		ex2->ee_len = cpu_to_le16(e1_len);
+		if (unwritten)
+			ext4_ext_mark_unwritten(ex2);
+		if (ext4_ext_is_unwritten(&tmp_ex))
+			ext4_ext_mark_unwritten(ex1);
+
+		ext4_ext_try_to_merge(handle, inode2, path2, ex2);
+		ext4_ext_try_to_merge(handle, inode1, path1, ex1);
+		*erp = ext4_ext_dirty(handle, inode2, path2 +
+				      path2->p_depth);
+		if (unlikely(*erp))
+			goto finish;
+		*erp = ext4_ext_dirty(handle, inode1, path1 +
+				      path1->p_depth);
+		/*
+		 * Looks scarry ah..? second inode already points to new blocks,
+		 * and it was successfully dirtied. But luckily error may happen
+		 * only due to journal error, so full transaction will be
+		 * aborted anyway.
+		 */
+		if (unlikely(*erp))
+			goto finish;
+		lblk1 += len;
+		lblk2 += len;
+		replaced_count += len;
+		count -= len;
+
+	repeat:
+		ext4_ext_drop_refs(path1);
+		kfree(path1);
+		ext4_ext_drop_refs(path2);
+		kfree(path2);
+		path1 = path2 = NULL;
+	}
+	return replaced_count;
+}
+
+/*
+ * ext4_clu_mapped - determine whether any block in a logical cluster has
+ *                   been mapped to a physical cluster
+ *
+ * @inode - file containing the logical cluster
+ * @lclu - logical cluster of interest
+ *
+ * Returns 1 if any block in the logical cluster is mapped, signifying
+ * that a physical cluster has been allocated for it.  Otherwise,
+ * returns 0.  Can also return negative error codes.  Derived from
+ * ext4_ext_map_blocks().
+ */
+int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_ext_path *path;
+	int depth, mapped = 0, err = 0;
+	struct ext4_extent *extent;
+	ext4_lblk_t first_lblk, first_lclu, last_lclu;
+
+	/*
+	 * if data can be stored inline, the logical cluster isn't
+	 * mapped - no physical clusters have been allocated, and the
+	 * file has no extents
+	 */
+	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ||
+	    ext4_has_inline_data(inode))
+		return 0;
+
+	/* search for the extent closest to the first block in the cluster */
+	path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
+	if (IS_ERR(path)) {
+		err = PTR_ERR(path);
+		path = NULL;
+		goto out;
+	}
+
+	depth = ext_depth(inode);
+
+	/*
+	 * A consistent leaf must not be empty.  This situation is possible,
+	 * though, _during_ tree modification, and it's why an assert can't
+	 * be put in ext4_find_extent().
+	 */
+	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
+		EXT4_ERROR_INODE(inode,
+		    "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
+				 (unsigned long) EXT4_C2B(sbi, lclu),
+				 depth, path[depth].p_block);
+		err = -EFSCORRUPTED;
+		goto out;
+	}
+
+	extent = path[depth].p_ext;
+
+	/* can't be mapped if the extent tree is empty */
+	if (extent == NULL)
+		goto out;
+
+	first_lblk = le32_to_cpu(extent->ee_block);
+	first_lclu = EXT4_B2C(sbi, first_lblk);
+
+	/*
+	 * Three possible outcomes at this point - found extent spanning
+	 * the target cluster, to the left of the target cluster, or to the
+	 * right of the target cluster.  The first two cases are handled here.
+	 * The last case indicates the target cluster is not mapped.
+	 */
+	if (lclu >= first_lclu) {
+		last_lclu = EXT4_B2C(sbi, first_lblk +
+				     ext4_ext_get_actual_len(extent) - 1);
+		if (lclu <= last_lclu) {
+			mapped = 1;
+		} else {
+			first_lblk = ext4_ext_next_allocated_block(path);
+			first_lclu = EXT4_B2C(sbi, first_lblk);
+			if (lclu == first_lclu)
+				mapped = 1;
+		}
+	}
+
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+
+	return err ? err : mapped;
+}
+
+/*
+ * Updates physical block address and unwritten status of extent
+ * starting at lblk start and of len. If such an extent doesn't exist,
+ * this function splits the extent tree appropriately to create an
+ * extent like this.  This function is called in the fast commit
+ * replay path.  Returns 0 on success and error on failure.
+ */
+int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
+			      int len, int unwritten, ext4_fsblk_t pblk)
+{
+	struct ext4_ext_path *path = NULL, *ppath;
+	struct ext4_extent *ex;
+	int ret;
+
+	path = ext4_find_extent(inode, start, NULL, 0);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	ex = path[path->p_depth].p_ext;
+	if (!ex) {
+		ret = -EFSCORRUPTED;
+		goto out;
+	}
+
+	if (le32_to_cpu(ex->ee_block) != start ||
+		ext4_ext_get_actual_len(ex) != len) {
+		/* We need to split this extent to match our extent first */
+		ppath = path;
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
+		up_write(&EXT4_I(inode)->i_data_sem);
+		if (ret)
+			goto out;
+		kfree(path);
+		path = ext4_find_extent(inode, start, NULL, 0);
+		if (IS_ERR(path))
+			return -1;
+		ppath = path;
+		ex = path[path->p_depth].p_ext;
+		WARN_ON(le32_to_cpu(ex->ee_block) != start);
+		if (ext4_ext_get_actual_len(ex) != len) {
+			down_write(&EXT4_I(inode)->i_data_sem);
+			ret = ext4_force_split_extent_at(NULL, inode, &ppath,
+							 start + len, 1);
+			up_write(&EXT4_I(inode)->i_data_sem);
+			if (ret)
+				goto out;
+			kfree(path);
+			path = ext4_find_extent(inode, start, NULL, 0);
+			if (IS_ERR(path))
+				return -EINVAL;
+			ex = path[path->p_depth].p_ext;
+		}
+	}
+	if (unwritten)
+		ext4_ext_mark_unwritten(ex);
+	else
+		ext4_ext_mark_initialized(ex);
+	ext4_ext_store_pblock(ex, pblk);
+	down_write(&EXT4_I(inode)->i_data_sem);
+	ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
+	up_write(&EXT4_I(inode)->i_data_sem);
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	ext4_mark_inode_dirty(NULL, inode);
+	return ret;
+}
+
+/* Try to shrink the extent tree */
+void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent *ex;
+	ext4_lblk_t old_cur, cur = 0;
+
+	while (cur < end) {
+		path = ext4_find_extent(inode, cur, NULL, 0);
+		if (IS_ERR(path))
+			return;
+		ex = path[path->p_depth].p_ext;
+		if (!ex) {
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			ext4_mark_inode_dirty(NULL, inode);
+			return;
+		}
+		old_cur = cur;
+		cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
+		if (cur <= old_cur)
+			cur = old_cur + 1;
+		ext4_ext_try_to_merge(NULL, inode, path, ex);
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
+		up_write(&EXT4_I(inode)->i_data_sem);
+		ext4_mark_inode_dirty(NULL, inode);
+		ext4_ext_drop_refs(path);
+		kfree(path);
+	}
+}
+
+/* Check if *cur is a hole and if it is, skip it */
+static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
+{
+	int ret;
+	struct ext4_map_blocks map;
+
+	map.m_lblk = *cur;
+	map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
+
+	ret = ext4_map_blocks(NULL, inode, &map, 0);
+	if (ret < 0)
+		return ret;
+	if (ret != 0)
+		return 0;
+	*cur = *cur + map.m_len;
+	return 0;
+}
+
+/* Count number of blocks used by this inode and update i_blocks */
+int ext4_ext_replay_set_iblocks(struct inode *inode)
+{
+	struct ext4_ext_path *path = NULL, *path2 = NULL;
+	struct ext4_extent *ex;
+	ext4_lblk_t cur = 0, end;
+	int numblks = 0, i, ret = 0;
+	ext4_fsblk_t cmp1, cmp2;
+	struct ext4_map_blocks map;
+
+	/* Determin the size of the file first */
+	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
+					EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	ex = path[path->p_depth].p_ext;
+	if (!ex) {
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		goto out;
+	}
+	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
+	ext4_ext_drop_refs(path);
+	kfree(path);
+
+	/* Count the number of data blocks */
+	cur = 0;
+	while (cur < end) {
+		map.m_lblk = cur;
+		map.m_len = end - cur;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0)
+			break;
+		if (ret > 0)
+			numblks += ret;
+		cur = cur + map.m_len;
+	}
+
+	/*
+	 * Count the number of extent tree blocks. We do it by looking up
+	 * two successive extents and determining the difference between
+	 * their paths. When path is different for 2 successive extents
+	 * we compare the blocks in the path at each level and increment
+	 * iblocks by total number of differences found.
+	 */
+	cur = 0;
+	ret = skip_hole(inode, &cur);
+	if (ret < 0)
+		goto out;
+	path = ext4_find_extent(inode, cur, NULL, 0);
+	if (IS_ERR(path))
+		goto out;
+	numblks += path->p_depth;
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	while (cur < end) {
+		path = ext4_find_extent(inode, cur, NULL, 0);
+		if (IS_ERR(path))
+			break;
+		ex = path[path->p_depth].p_ext;
+		if (!ex) {
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			return 0;
+		}
+		cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
+					ext4_ext_get_actual_len(ex));
+		ret = skip_hole(inode, &cur);
+		if (ret < 0) {
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			break;
+		}
+		path2 = ext4_find_extent(inode, cur, NULL, 0);
+		if (IS_ERR(path2)) {
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			break;
+		}
+		ex = path2[path2->p_depth].p_ext;
+		for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
+			cmp1 = cmp2 = 0;
+			if (i <= path->p_depth)
+				cmp1 = path[i].p_bh ?
+					path[i].p_bh->b_blocknr : 0;
+			if (i <= path2->p_depth)
+				cmp2 = path2[i].p_bh ?
+					path2[i].p_bh->b_blocknr : 0;
+			if (cmp1 != cmp2 && cmp2 != 0)
+				numblks++;
+		}
+		ext4_ext_drop_refs(path);
+		ext4_ext_drop_refs(path2);
+		kfree(path);
+		kfree(path2);
+	}
+
+out:
+	inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
+	ext4_mark_inode_dirty(NULL, inode);
+	return 0;
+}
+
+int ext4_ext_clear_bb(struct inode *inode)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent *ex;
+	ext4_lblk_t cur = 0, end;
+	int j, ret = 0;
+	struct ext4_map_blocks map;
+
+	/* Determin the size of the file first */
+	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
+					EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	ex = path[path->p_depth].p_ext;
+	if (!ex) {
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		return 0;
+	}
+	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
+	ext4_ext_drop_refs(path);
+	kfree(path);
+
+	cur = 0;
+	while (cur < end) {
+		map.m_lblk = cur;
+		map.m_len = end - cur;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0)
+			break;
+		if (ret > 0) {
+			path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
+			if (!IS_ERR_OR_NULL(path)) {
+				for (j = 0; j < path->p_depth; j++) {
+
+					ext4_mb_mark_bb(inode->i_sb,
+							path[j].p_block, 1, 0);
+					ext4_fc_record_regions(inode->i_sb, inode->i_ino,
+							0, path[j].p_block, 1, 1);
+				}
+				ext4_ext_drop_refs(path);
+				kfree(path);
+			}
+			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
+			ext4_fc_record_regions(inode->i_sb, inode->i_ino,
+					map.m_lblk, map.m_pblk, map.m_len, 1);
+		}
+		cur = cur + map.m_len;
+	}
+
+	return 0;
+}
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
new file mode 100644
index 000000000..cccbdfd49
--- /dev/null
+++ b/fs/ext4/extents_status.c
@@ -0,0 +1,2317 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  fs/ext4/extents_status.c
+ *
+ * Written by Yongqiang Yang <xiaoqiangnk@gmail.com>
+ * Modified by
+ *	Allison Henderson <achender@linux.vnet.ibm.com>
+ *	Hugh Dickins <hughd@google.com>
+ *	Zheng Liu <wenqing.lz@taobao.com>
+ *
+ * Ext4 extents status tree core functions.
+ */
+#include <linux/list_sort.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "ext4.h"
+
+#include <trace/events/ext4.h>
+
+/*
+ * According to previous discussion in Ext4 Developer Workshop, we
+ * will introduce a new structure called io tree to track all extent
+ * status in order to solve some problems that we have met
+ * (e.g. Reservation space warning), and provide extent-level locking.
+ * Delay extent tree is the first step to achieve this goal.  It is
+ * original built by Yongqiang Yang.  At that time it is called delay
+ * extent tree, whose goal is only track delayed extents in memory to
+ * simplify the implementation of fiemap and bigalloc, and introduce
+ * lseek SEEK_DATA/SEEK_HOLE support.  That is why it is still called
+ * delay extent tree at the first commit.  But for better understand
+ * what it does, it has been rename to extent status tree.
+ *
+ * Step1:
+ * Currently the first step has been done.  All delayed extents are
+ * tracked in the tree.  It maintains the delayed extent when a delayed
+ * allocation is issued, and the delayed extent is written out or
+ * invalidated.  Therefore the implementation of fiemap and bigalloc
+ * are simplified, and SEEK_DATA/SEEK_HOLE are introduced.
+ *
+ * The following comment describes the implemenmtation of extent
+ * status tree and future works.
+ *
+ * Step2:
+ * In this step all extent status are tracked by extent status tree.
+ * Thus, we can first try to lookup a block mapping in this tree before
+ * finding it in extent tree.  Hence, single extent cache can be removed
+ * because extent status tree can do a better job.  Extents in status
+ * tree are loaded on-demand.  Therefore, the extent status tree may not
+ * contain all of the extents in a file.  Meanwhile we define a shrinker
+ * to reclaim memory from extent status tree because fragmented extent
+ * tree will make status tree cost too much memory.  written/unwritten/-
+ * hole extents in the tree will be reclaimed by this shrinker when we
+ * are under high memory pressure.  Delayed extents will not be
+ * reclimed because fiemap, bigalloc, and seek_data/hole need it.
+ */
+
+/*
+ * Extent status tree implementation for ext4.
+ *
+ *
+ * ==========================================================================
+ * Extent status tree tracks all extent status.
+ *
+ * 1. Why we need to implement extent status tree?
+ *
+ * Without extent status tree, ext4 identifies a delayed extent by looking
+ * up page cache, this has several deficiencies - complicated, buggy,
+ * and inefficient code.
+ *
+ * FIEMAP, SEEK_HOLE/DATA, bigalloc, and writeout all need to know if a
+ * block or a range of blocks are belonged to a delayed extent.
+ *
+ * Let us have a look at how they do without extent status tree.
+ *   --	FIEMAP
+ *	FIEMAP looks up page cache to identify delayed allocations from holes.
+ *
+ *   --	SEEK_HOLE/DATA
+ *	SEEK_HOLE/DATA has the same problem as FIEMAP.
+ *
+ *   --	bigalloc
+ *	bigalloc looks up page cache to figure out if a block is
+ *	already under delayed allocation or not to determine whether
+ *	quota reserving is needed for the cluster.
+ *
+ *   --	writeout
+ *	Writeout looks up whole page cache to see if a buffer is
+ *	mapped, If there are not very many delayed buffers, then it is
+ *	time consuming.
+ *
+ * With extent status tree implementation, FIEMAP, SEEK_HOLE/DATA,
+ * bigalloc and writeout can figure out if a block or a range of
+ * blocks is under delayed allocation(belonged to a delayed extent) or
+ * not by searching the extent tree.
+ *
+ *
+ * ==========================================================================
+ * 2. Ext4 extent status tree impelmentation
+ *
+ *   --	extent
+ *	A extent is a range of blocks which are contiguous logically and
+ *	physically.  Unlike extent in extent tree, this extent in ext4 is
+ *	a in-memory struct, there is no corresponding on-disk data.  There
+ *	is no limit on length of extent, so an extent can contain as many
+ *	blocks as they are contiguous logically and physically.
+ *
+ *   --	extent status tree
+ *	Every inode has an extent status tree and all allocation blocks
+ *	are added to the tree with different status.  The extent in the
+ *	tree are ordered by logical block no.
+ *
+ *   --	operations on a extent status tree
+ *	There are three important operations on a delayed extent tree: find
+ *	next extent, adding a extent(a range of blocks) and removing a extent.
+ *
+ *   --	race on a extent status tree
+ *	Extent status tree is protected by inode->i_es_lock.
+ *
+ *   --	memory consumption
+ *      Fragmented extent tree will make extent status tree cost too much
+ *      memory.  Hence, we will reclaim written/unwritten/hole extents from
+ *      the tree under a heavy memory pressure.
+ *
+ *
+ * ==========================================================================
+ * 3. Performance analysis
+ *
+ *   --	overhead
+ *	1. There is a cache extent for write access, so if writes are
+ *	not very random, adding space operaions are in O(1) time.
+ *
+ *   --	gain
+ *	2. Code is much simpler, more readable, more maintainable and
+ *	more efficient.
+ *
+ *
+ * ==========================================================================
+ * 4. TODO list
+ *
+ *   -- Refactor delayed space reservation
+ *
+ *   -- Extent-level locking
+ */
+
+static struct kmem_cache *ext4_es_cachep;
+static struct kmem_cache *ext4_pending_cachep;
+
+static int __es_insert_extent(struct inode *inode, struct extent_status *newes,
+			      struct extent_status *prealloc);
+static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
+			      ext4_lblk_t end, int *reserved,
+			      struct extent_status *prealloc);
+static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan);
+static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan,
+		       struct ext4_inode_info *locked_ei);
+static int __revise_pending(struct inode *inode, ext4_lblk_t lblk,
+			    ext4_lblk_t len,
+			    struct pending_reservation **prealloc);
+
+int __init ext4_init_es(void)
+{
+	ext4_es_cachep = kmem_cache_create("ext4_extent_status",
+					   sizeof(struct extent_status),
+					   0, (SLAB_RECLAIM_ACCOUNT), NULL);
+	if (ext4_es_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+void ext4_exit_es(void)
+{
+	kmem_cache_destroy(ext4_es_cachep);
+}
+
+void ext4_es_init_tree(struct ext4_es_tree *tree)
+{
+	tree->root = RB_ROOT;
+	tree->cache_es = NULL;
+}
+
+#ifdef ES_DEBUG__
+static void ext4_es_print_tree(struct inode *inode)
+{
+	struct ext4_es_tree *tree;
+	struct rb_node *node;
+
+	printk(KERN_DEBUG "status extents for inode %lu:", inode->i_ino);
+	tree = &EXT4_I(inode)->i_es_tree;
+	node = rb_first(&tree->root);
+	while (node) {
+		struct extent_status *es;
+		es = rb_entry(node, struct extent_status, rb_node);
+		printk(KERN_DEBUG " [%u/%u) %llu %x",
+		       es->es_lblk, es->es_len,
+		       ext4_es_pblock(es), ext4_es_status(es));
+		node = rb_next(node);
+	}
+	printk(KERN_DEBUG "\n");
+}
+#else
+#define ext4_es_print_tree(inode)
+#endif
+
+static inline ext4_lblk_t ext4_es_end(struct extent_status *es)
+{
+	BUG_ON(es->es_lblk + es->es_len < es->es_lblk);
+	return es->es_lblk + es->es_len - 1;
+}
+
+/*
+ * search through the tree for an delayed extent with a given offset.  If
+ * it can't be found, try to find next extent.
+ */
+static struct extent_status *__es_tree_search(struct rb_root *root,
+					      ext4_lblk_t lblk)
+{
+	struct rb_node *node = root->rb_node;
+	struct extent_status *es = NULL;
+
+	while (node) {
+		es = rb_entry(node, struct extent_status, rb_node);
+		if (lblk < es->es_lblk)
+			node = node->rb_left;
+		else if (lblk > ext4_es_end(es))
+			node = node->rb_right;
+		else
+			return es;
+	}
+
+	if (es && lblk < es->es_lblk)
+		return es;
+
+	if (es && lblk > ext4_es_end(es)) {
+		node = rb_next(&es->rb_node);
+		return node ? rb_entry(node, struct extent_status, rb_node) :
+			      NULL;
+	}
+
+	return NULL;
+}
+
+/*
+ * ext4_es_find_extent_range - find extent with specified status within block
+ *                             range or next extent following block range in
+ *                             extents status tree
+ *
+ * @inode - file containing the range
+ * @matching_fn - pointer to function that matches extents with desired status
+ * @lblk - logical block defining start of range
+ * @end - logical block defining end of range
+ * @es - extent found, if any
+ *
+ * Find the first extent within the block range specified by @lblk and @end
+ * in the extents status tree that satisfies @matching_fn.  If a match
+ * is found, it's returned in @es.  If not, and a matching extent is found
+ * beyond the block range, it's returned in @es.  If no match is found, an
+ * extent is returned in @es whose es_lblk, es_len, and es_pblk components
+ * are 0.
+ */
+static void __es_find_extent_range(struct inode *inode,
+				   int (*matching_fn)(struct extent_status *es),
+				   ext4_lblk_t lblk, ext4_lblk_t end,
+				   struct extent_status *es)
+{
+	struct ext4_es_tree *tree = NULL;
+	struct extent_status *es1 = NULL;
+	struct rb_node *node;
+
+	WARN_ON(es == NULL);
+	WARN_ON(end < lblk);
+
+	tree = &EXT4_I(inode)->i_es_tree;
+
+	/* see if the extent has been cached */
+	es->es_lblk = es->es_len = es->es_pblk = 0;
+	es1 = READ_ONCE(tree->cache_es);
+	if (es1 && in_range(lblk, es1->es_lblk, es1->es_len)) {
+		es_debug("%u cached by [%u/%u) %llu %x\n",
+			 lblk, es1->es_lblk, es1->es_len,
+			 ext4_es_pblock(es1), ext4_es_status(es1));
+		goto out;
+	}
+
+	es1 = __es_tree_search(&tree->root, lblk);
+
+out:
+	if (es1 && !matching_fn(es1)) {
+		while ((node = rb_next(&es1->rb_node)) != NULL) {
+			es1 = rb_entry(node, struct extent_status, rb_node);
+			if (es1->es_lblk > end) {
+				es1 = NULL;
+				break;
+			}
+			if (matching_fn(es1))
+				break;
+		}
+	}
+
+	if (es1 && matching_fn(es1)) {
+		WRITE_ONCE(tree->cache_es, es1);
+		es->es_lblk = es1->es_lblk;
+		es->es_len = es1->es_len;
+		es->es_pblk = es1->es_pblk;
+	}
+
+}
+
+/*
+ * Locking for __es_find_extent_range() for external use
+ */
+void ext4_es_find_extent_range(struct inode *inode,
+			       int (*matching_fn)(struct extent_status *es),
+			       ext4_lblk_t lblk, ext4_lblk_t end,
+			       struct extent_status *es)
+{
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return;
+
+	trace_ext4_es_find_extent_range_enter(inode, lblk);
+
+	read_lock(&EXT4_I(inode)->i_es_lock);
+	__es_find_extent_range(inode, matching_fn, lblk, end, es);
+	read_unlock(&EXT4_I(inode)->i_es_lock);
+
+	trace_ext4_es_find_extent_range_exit(inode, es);
+}
+
+/*
+ * __es_scan_range - search block range for block with specified status
+ *                   in extents status tree
+ *
+ * @inode - file containing the range
+ * @matching_fn - pointer to function that matches extents with desired status
+ * @lblk - logical block defining start of range
+ * @end - logical block defining end of range
+ *
+ * Returns true if at least one block in the specified block range satisfies
+ * the criterion specified by @matching_fn, and false if not.  If at least
+ * one extent has the specified status, then there is at least one block
+ * in the cluster with that status.  Should only be called by code that has
+ * taken i_es_lock.
+ */
+static bool __es_scan_range(struct inode *inode,
+			    int (*matching_fn)(struct extent_status *es),
+			    ext4_lblk_t start, ext4_lblk_t end)
+{
+	struct extent_status es;
+
+	__es_find_extent_range(inode, matching_fn, start, end, &es);
+	if (es.es_len == 0)
+		return false;   /* no matching extent in the tree */
+	else if (es.es_lblk <= start &&
+		 start < es.es_lblk + es.es_len)
+		return true;
+	else if (start <= es.es_lblk && es.es_lblk <= end)
+		return true;
+	else
+		return false;
+}
+/*
+ * Locking for __es_scan_range() for external use
+ */
+bool ext4_es_scan_range(struct inode *inode,
+			int (*matching_fn)(struct extent_status *es),
+			ext4_lblk_t lblk, ext4_lblk_t end)
+{
+	bool ret;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return false;
+
+	read_lock(&EXT4_I(inode)->i_es_lock);
+	ret = __es_scan_range(inode, matching_fn, lblk, end);
+	read_unlock(&EXT4_I(inode)->i_es_lock);
+
+	return ret;
+}
+
+/*
+ * __es_scan_clu - search cluster for block with specified status in
+ *                 extents status tree
+ *
+ * @inode - file containing the cluster
+ * @matching_fn - pointer to function that matches extents with desired status
+ * @lblk - logical block in cluster to be searched
+ *
+ * Returns true if at least one extent in the cluster containing @lblk
+ * satisfies the criterion specified by @matching_fn, and false if not.  If at
+ * least one extent has the specified status, then there is at least one block
+ * in the cluster with that status.  Should only be called by code that has
+ * taken i_es_lock.
+ */
+static bool __es_scan_clu(struct inode *inode,
+			  int (*matching_fn)(struct extent_status *es),
+			  ext4_lblk_t lblk)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	ext4_lblk_t lblk_start, lblk_end;
+
+	lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
+	lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
+
+	return __es_scan_range(inode, matching_fn, lblk_start, lblk_end);
+}
+
+/*
+ * Locking for __es_scan_clu() for external use
+ */
+bool ext4_es_scan_clu(struct inode *inode,
+		      int (*matching_fn)(struct extent_status *es),
+		      ext4_lblk_t lblk)
+{
+	bool ret;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return false;
+
+	read_lock(&EXT4_I(inode)->i_es_lock);
+	ret = __es_scan_clu(inode, matching_fn, lblk);
+	read_unlock(&EXT4_I(inode)->i_es_lock);
+
+	return ret;
+}
+
+static void ext4_es_list_add(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+	if (!list_empty(&ei->i_es_list))
+		return;
+
+	spin_lock(&sbi->s_es_lock);
+	if (list_empty(&ei->i_es_list)) {
+		list_add_tail(&ei->i_es_list, &sbi->s_es_list);
+		sbi->s_es_nr_inode++;
+	}
+	spin_unlock(&sbi->s_es_lock);
+}
+
+static void ext4_es_list_del(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+	spin_lock(&sbi->s_es_lock);
+	if (!list_empty(&ei->i_es_list)) {
+		list_del_init(&ei->i_es_list);
+		sbi->s_es_nr_inode--;
+		WARN_ON_ONCE(sbi->s_es_nr_inode < 0);
+	}
+	spin_unlock(&sbi->s_es_lock);
+}
+
+static inline struct pending_reservation *__alloc_pending(bool nofail)
+{
+	if (!nofail)
+		return kmem_cache_alloc(ext4_pending_cachep, GFP_ATOMIC);
+
+	return kmem_cache_zalloc(ext4_pending_cachep, GFP_KERNEL | __GFP_NOFAIL);
+}
+
+static inline void __free_pending(struct pending_reservation *pr)
+{
+	kmem_cache_free(ext4_pending_cachep, pr);
+}
+
+/*
+ * Returns true if we cannot fail to allocate memory for this extent_status
+ * entry and cannot reclaim it until its status changes.
+ */
+static inline bool ext4_es_must_keep(struct extent_status *es)
+{
+	/* fiemap, bigalloc, and seek_data/hole need to use it. */
+	if (ext4_es_is_delayed(es))
+		return true;
+
+	return false;
+}
+
+static inline struct extent_status *__es_alloc_extent(bool nofail)
+{
+	if (!nofail)
+		return kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC);
+
+	return kmem_cache_zalloc(ext4_es_cachep, GFP_KERNEL | __GFP_NOFAIL);
+}
+
+static void ext4_es_init_extent(struct inode *inode, struct extent_status *es,
+		ext4_lblk_t lblk, ext4_lblk_t len, ext4_fsblk_t pblk)
+{
+	es->es_lblk = lblk;
+	es->es_len = len;
+	es->es_pblk = pblk;
+
+	/* We never try to reclaim a must kept extent, so we don't count it. */
+	if (!ext4_es_must_keep(es)) {
+		if (!EXT4_I(inode)->i_es_shk_nr++)
+			ext4_es_list_add(inode);
+		percpu_counter_inc(&EXT4_SB(inode->i_sb)->
+					s_es_stats.es_stats_shk_cnt);
+	}
+
+	EXT4_I(inode)->i_es_all_nr++;
+	percpu_counter_inc(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt);
+}
+
+static inline void __es_free_extent(struct extent_status *es)
+{
+	kmem_cache_free(ext4_es_cachep, es);
+}
+
+static void ext4_es_free_extent(struct inode *inode, struct extent_status *es)
+{
+	EXT4_I(inode)->i_es_all_nr--;
+	percpu_counter_dec(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt);
+
+	/* Decrease the shrink counter when we can reclaim the extent. */
+	if (!ext4_es_must_keep(es)) {
+		BUG_ON(EXT4_I(inode)->i_es_shk_nr == 0);
+		if (!--EXT4_I(inode)->i_es_shk_nr)
+			ext4_es_list_del(inode);
+		percpu_counter_dec(&EXT4_SB(inode->i_sb)->
+					s_es_stats.es_stats_shk_cnt);
+	}
+
+	__es_free_extent(es);
+}
+
+/*
+ * Check whether or not two extents can be merged
+ * Condition:
+ *  - logical block number is contiguous
+ *  - physical block number is contiguous
+ *  - status is equal
+ */
+static int ext4_es_can_be_merged(struct extent_status *es1,
+				 struct extent_status *es2)
+{
+	if (ext4_es_type(es1) != ext4_es_type(es2))
+		return 0;
+
+	if (((__u64) es1->es_len) + es2->es_len > EXT_MAX_BLOCKS) {
+		pr_warn("ES assertion failed when merging extents. "
+			"The sum of lengths of es1 (%d) and es2 (%d) "
+			"is bigger than allowed file size (%d)\n",
+			es1->es_len, es2->es_len, EXT_MAX_BLOCKS);
+		WARN_ON(1);
+		return 0;
+	}
+
+	if (((__u64) es1->es_lblk) + es1->es_len != es2->es_lblk)
+		return 0;
+
+	if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) &&
+	    (ext4_es_pblock(es1) + es1->es_len == ext4_es_pblock(es2)))
+		return 1;
+
+	if (ext4_es_is_hole(es1))
+		return 1;
+
+	/* we need to check delayed extent is without unwritten status */
+	if (ext4_es_is_delayed(es1) && !ext4_es_is_unwritten(es1))
+		return 1;
+
+	return 0;
+}
+
+static struct extent_status *
+ext4_es_try_to_merge_left(struct inode *inode, struct extent_status *es)
+{
+	struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
+	struct extent_status *es1;
+	struct rb_node *node;
+
+	node = rb_prev(&es->rb_node);
+	if (!node)
+		return es;
+
+	es1 = rb_entry(node, struct extent_status, rb_node);
+	if (ext4_es_can_be_merged(es1, es)) {
+		es1->es_len += es->es_len;
+		if (ext4_es_is_referenced(es))
+			ext4_es_set_referenced(es1);
+		rb_erase(&es->rb_node, &tree->root);
+		ext4_es_free_extent(inode, es);
+		es = es1;
+	}
+
+	return es;
+}
+
+static struct extent_status *
+ext4_es_try_to_merge_right(struct inode *inode, struct extent_status *es)
+{
+	struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
+	struct extent_status *es1;
+	struct rb_node *node;
+
+	node = rb_next(&es->rb_node);
+	if (!node)
+		return es;
+
+	es1 = rb_entry(node, struct extent_status, rb_node);
+	if (ext4_es_can_be_merged(es, es1)) {
+		es->es_len += es1->es_len;
+		if (ext4_es_is_referenced(es1))
+			ext4_es_set_referenced(es);
+		rb_erase(node, &tree->root);
+		ext4_es_free_extent(inode, es1);
+	}
+
+	return es;
+}
+
+#ifdef ES_AGGRESSIVE_TEST
+#include "ext4_extents.h"	/* Needed when ES_AGGRESSIVE_TEST is defined */
+
+static void ext4_es_insert_extent_ext_check(struct inode *inode,
+					    struct extent_status *es)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent *ex;
+	ext4_lblk_t ee_block;
+	ext4_fsblk_t ee_start;
+	unsigned short ee_len;
+	int depth, ee_status, es_status;
+
+	path = ext4_find_extent(inode, es->es_lblk, NULL, EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return;
+
+	depth = ext_depth(inode);
+	ex = path[depth].p_ext;
+
+	if (ex) {
+
+		ee_block = le32_to_cpu(ex->ee_block);
+		ee_start = ext4_ext_pblock(ex);
+		ee_len = ext4_ext_get_actual_len(ex);
+
+		ee_status = ext4_ext_is_unwritten(ex) ? 1 : 0;
+		es_status = ext4_es_is_unwritten(es) ? 1 : 0;
+
+		/*
+		 * Make sure ex and es are not overlap when we try to insert
+		 * a delayed/hole extent.
+		 */
+		if (!ext4_es_is_written(es) && !ext4_es_is_unwritten(es)) {
+			if (in_range(es->es_lblk, ee_block, ee_len)) {
+				pr_warn("ES insert assertion failed for "
+					"inode: %lu we can find an extent "
+					"at block [%d/%d/%llu/%c], but we "
+					"want to add a delayed/hole extent "
+					"[%d/%d/%llu/%x]\n",
+					inode->i_ino, ee_block, ee_len,
+					ee_start, ee_status ? 'u' : 'w',
+					es->es_lblk, es->es_len,
+					ext4_es_pblock(es), ext4_es_status(es));
+			}
+			goto out;
+		}
+
+		/*
+		 * We don't check ee_block == es->es_lblk, etc. because es
+		 * might be a part of whole extent, vice versa.
+		 */
+		if (es->es_lblk < ee_block ||
+		    ext4_es_pblock(es) != ee_start + es->es_lblk - ee_block) {
+			pr_warn("ES insert assertion failed for inode: %lu "
+				"ex_status [%d/%d/%llu/%c] != "
+				"es_status [%d/%d/%llu/%c]\n", inode->i_ino,
+				ee_block, ee_len, ee_start,
+				ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
+				ext4_es_pblock(es), es_status ? 'u' : 'w');
+			goto out;
+		}
+
+		if (ee_status ^ es_status) {
+			pr_warn("ES insert assertion failed for inode: %lu "
+				"ex_status [%d/%d/%llu/%c] != "
+				"es_status [%d/%d/%llu/%c]\n", inode->i_ino,
+				ee_block, ee_len, ee_start,
+				ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
+				ext4_es_pblock(es), es_status ? 'u' : 'w');
+		}
+	} else {
+		/*
+		 * We can't find an extent on disk.  So we need to make sure
+		 * that we don't want to add an written/unwritten extent.
+		 */
+		if (!ext4_es_is_delayed(es) && !ext4_es_is_hole(es)) {
+			pr_warn("ES insert assertion failed for inode: %lu "
+				"can't find an extent at block %d but we want "
+				"to add a written/unwritten extent "
+				"[%d/%d/%llu/%x]\n", inode->i_ino,
+				es->es_lblk, es->es_lblk, es->es_len,
+				ext4_es_pblock(es), ext4_es_status(es));
+		}
+	}
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+}
+
+static void ext4_es_insert_extent_ind_check(struct inode *inode,
+					    struct extent_status *es)
+{
+	struct ext4_map_blocks map;
+	int retval;
+
+	/*
+	 * Here we call ext4_ind_map_blocks to lookup a block mapping because
+	 * 'Indirect' structure is defined in indirect.c.  So we couldn't
+	 * access direct/indirect tree from outside.  It is too dirty to define
+	 * this function in indirect.c file.
+	 */
+
+	map.m_lblk = es->es_lblk;
+	map.m_len = es->es_len;
+
+	retval = ext4_ind_map_blocks(NULL, inode, &map, 0);
+	if (retval > 0) {
+		if (ext4_es_is_delayed(es) || ext4_es_is_hole(es)) {
+			/*
+			 * We want to add a delayed/hole extent but this
+			 * block has been allocated.
+			 */
+			pr_warn("ES insert assertion failed for inode: %lu "
+				"We can find blocks but we want to add a "
+				"delayed/hole extent [%d/%d/%llu/%x]\n",
+				inode->i_ino, es->es_lblk, es->es_len,
+				ext4_es_pblock(es), ext4_es_status(es));
+			return;
+		} else if (ext4_es_is_written(es)) {
+			if (retval != es->es_len) {
+				pr_warn("ES insert assertion failed for "
+					"inode: %lu retval %d != es_len %d\n",
+					inode->i_ino, retval, es->es_len);
+				return;
+			}
+			if (map.m_pblk != ext4_es_pblock(es)) {
+				pr_warn("ES insert assertion failed for "
+					"inode: %lu m_pblk %llu != "
+					"es_pblk %llu\n",
+					inode->i_ino, map.m_pblk,
+					ext4_es_pblock(es));
+				return;
+			}
+		} else {
+			/*
+			 * We don't need to check unwritten extent because
+			 * indirect-based file doesn't have it.
+			 */
+			BUG();
+		}
+	} else if (retval == 0) {
+		if (ext4_es_is_written(es)) {
+			pr_warn("ES insert assertion failed for inode: %lu "
+				"We can't find the block but we want to add "
+				"a written extent [%d/%d/%llu/%x]\n",
+				inode->i_ino, es->es_lblk, es->es_len,
+				ext4_es_pblock(es), ext4_es_status(es));
+			return;
+		}
+	}
+}
+
+static inline void ext4_es_insert_extent_check(struct inode *inode,
+					       struct extent_status *es)
+{
+	/*
+	 * We don't need to worry about the race condition because
+	 * caller takes i_data_sem locking.
+	 */
+	BUG_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		ext4_es_insert_extent_ext_check(inode, es);
+	else
+		ext4_es_insert_extent_ind_check(inode, es);
+}
+#else
+static inline void ext4_es_insert_extent_check(struct inode *inode,
+					       struct extent_status *es)
+{
+}
+#endif
+
+static int __es_insert_extent(struct inode *inode, struct extent_status *newes,
+			      struct extent_status *prealloc)
+{
+	struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
+	struct rb_node **p = &tree->root.rb_node;
+	struct rb_node *parent = NULL;
+	struct extent_status *es;
+
+	while (*p) {
+		parent = *p;
+		es = rb_entry(parent, struct extent_status, rb_node);
+
+		if (newes->es_lblk < es->es_lblk) {
+			if (ext4_es_can_be_merged(newes, es)) {
+				/*
+				 * Here we can modify es_lblk directly
+				 * because it isn't overlapped.
+				 */
+				es->es_lblk = newes->es_lblk;
+				es->es_len += newes->es_len;
+				if (ext4_es_is_written(es) ||
+				    ext4_es_is_unwritten(es))
+					ext4_es_store_pblock(es,
+							     newes->es_pblk);
+				es = ext4_es_try_to_merge_left(inode, es);
+				goto out;
+			}
+			p = &(*p)->rb_left;
+		} else if (newes->es_lblk > ext4_es_end(es)) {
+			if (ext4_es_can_be_merged(es, newes)) {
+				es->es_len += newes->es_len;
+				es = ext4_es_try_to_merge_right(inode, es);
+				goto out;
+			}
+			p = &(*p)->rb_right;
+		} else {
+			BUG();
+			return -EINVAL;
+		}
+	}
+
+	if (prealloc)
+		es = prealloc;
+	else
+		es = __es_alloc_extent(false);
+	if (!es)
+		return -ENOMEM;
+	ext4_es_init_extent(inode, es, newes->es_lblk, newes->es_len,
+			    newes->es_pblk);
+
+	rb_link_node(&es->rb_node, parent, p);
+	rb_insert_color(&es->rb_node, &tree->root);
+
+out:
+	tree->cache_es = es;
+	return 0;
+}
+
+/*
+ * ext4_es_insert_extent() adds information to an inode's extent
+ * status tree.
+ *
+ * Return 0 on success, error code on failure.
+ */
+int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
+			  ext4_lblk_t len, ext4_fsblk_t pblk,
+			  unsigned int status)
+{
+	struct extent_status newes;
+	ext4_lblk_t end = lblk + len - 1;
+	int err1 = 0, err2 = 0, err3 = 0;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct extent_status *es1 = NULL;
+	struct extent_status *es2 = NULL;
+	struct pending_reservation *pr = NULL;
+	bool revise_pending = false;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	es_debug("add [%u/%u) %llu %x to extent status tree of inode %lu\n",
+		 lblk, len, pblk, status, inode->i_ino);
+
+	if (!len)
+		return 0;
+
+	BUG_ON(end < lblk);
+
+	if ((status & EXTENT_STATUS_DELAYED) &&
+	    (status & EXTENT_STATUS_WRITTEN)) {
+		ext4_warning(inode->i_sb, "Inserting extent [%u/%u] as "
+				" delayed and written which can potentially "
+				" cause data loss.", lblk, len);
+		WARN_ON(1);
+	}
+
+	newes.es_lblk = lblk;
+	newes.es_len = len;
+	ext4_es_store_pblock_status(&newes, pblk, status);
+	trace_ext4_es_insert_extent(inode, &newes);
+
+	ext4_es_insert_extent_check(inode, &newes);
+
+	revise_pending = sbi->s_cluster_ratio > 1 &&
+			 test_opt(inode->i_sb, DELALLOC) &&
+			 (status & (EXTENT_STATUS_WRITTEN |
+				    EXTENT_STATUS_UNWRITTEN));
+retry:
+	if (err1 && !es1)
+		es1 = __es_alloc_extent(true);
+	if ((err1 || err2) && !es2)
+		es2 = __es_alloc_extent(true);
+	if ((err1 || err2 || err3) && revise_pending && !pr)
+		pr = __alloc_pending(true);
+	write_lock(&EXT4_I(inode)->i_es_lock);
+
+	err1 = __es_remove_extent(inode, lblk, end, NULL, es1);
+	if (err1 != 0)
+		goto error;
+	/* Free preallocated extent if it didn't get used. */
+	if (es1) {
+		if (!es1->es_len)
+			__es_free_extent(es1);
+		es1 = NULL;
+	}
+
+	err2 = __es_insert_extent(inode, &newes, es2);
+	if (err2 == -ENOMEM && !ext4_es_must_keep(&newes))
+		err2 = 0;
+	if (err2 != 0)
+		goto error;
+	/* Free preallocated extent if it didn't get used. */
+	if (es2) {
+		if (!es2->es_len)
+			__es_free_extent(es2);
+		es2 = NULL;
+	}
+
+	if (revise_pending) {
+		err3 = __revise_pending(inode, lblk, len, &pr);
+		if (err3 != 0)
+			goto error;
+		if (pr) {
+			__free_pending(pr);
+			pr = NULL;
+		}
+	}
+error:
+	write_unlock(&EXT4_I(inode)->i_es_lock);
+	if (err1 || err2 || err3)
+		goto retry;
+
+	ext4_es_print_tree(inode);
+	return 0;
+}
+
+/*
+ * ext4_es_cache_extent() inserts information into the extent status
+ * tree if and only if there isn't information about the range in
+ * question already.
+ */
+void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
+			  ext4_lblk_t len, ext4_fsblk_t pblk,
+			  unsigned int status)
+{
+	struct extent_status *es;
+	struct extent_status newes;
+	ext4_lblk_t end = lblk + len - 1;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return;
+
+	newes.es_lblk = lblk;
+	newes.es_len = len;
+	ext4_es_store_pblock_status(&newes, pblk, status);
+	trace_ext4_es_cache_extent(inode, &newes);
+
+	if (!len)
+		return;
+
+	BUG_ON(end < lblk);
+
+	write_lock(&EXT4_I(inode)->i_es_lock);
+
+	es = __es_tree_search(&EXT4_I(inode)->i_es_tree.root, lblk);
+	if (!es || es->es_lblk > end)
+		__es_insert_extent(inode, &newes, NULL);
+	write_unlock(&EXT4_I(inode)->i_es_lock);
+}
+
+/*
+ * ext4_es_lookup_extent() looks up an extent in extent status tree.
+ *
+ * ext4_es_lookup_extent is called by ext4_map_blocks/ext4_da_map_blocks.
+ *
+ * Return: 1 on found, 0 on not
+ */
+int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
+			  ext4_lblk_t *next_lblk,
+			  struct extent_status *es)
+{
+	struct ext4_es_tree *tree;
+	struct ext4_es_stats *stats;
+	struct extent_status *es1 = NULL;
+	struct rb_node *node;
+	int found = 0;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	trace_ext4_es_lookup_extent_enter(inode, lblk);
+	es_debug("lookup extent in block %u\n", lblk);
+
+	tree = &EXT4_I(inode)->i_es_tree;
+	read_lock(&EXT4_I(inode)->i_es_lock);
+
+	/* find extent in cache firstly */
+	es->es_lblk = es->es_len = es->es_pblk = 0;
+	es1 = READ_ONCE(tree->cache_es);
+	if (es1 && in_range(lblk, es1->es_lblk, es1->es_len)) {
+		es_debug("%u cached by [%u/%u)\n",
+			 lblk, es1->es_lblk, es1->es_len);
+		found = 1;
+		goto out;
+	}
+
+	node = tree->root.rb_node;
+	while (node) {
+		es1 = rb_entry(node, struct extent_status, rb_node);
+		if (lblk < es1->es_lblk)
+			node = node->rb_left;
+		else if (lblk > ext4_es_end(es1))
+			node = node->rb_right;
+		else {
+			found = 1;
+			break;
+		}
+	}
+
+out:
+	stats = &EXT4_SB(inode->i_sb)->s_es_stats;
+	if (found) {
+		BUG_ON(!es1);
+		es->es_lblk = es1->es_lblk;
+		es->es_len = es1->es_len;
+		es->es_pblk = es1->es_pblk;
+		if (!ext4_es_is_referenced(es1))
+			ext4_es_set_referenced(es1);
+		percpu_counter_inc(&stats->es_stats_cache_hits);
+		if (next_lblk) {
+			node = rb_next(&es1->rb_node);
+			if (node) {
+				es1 = rb_entry(node, struct extent_status,
+					       rb_node);
+				*next_lblk = es1->es_lblk;
+			} else
+				*next_lblk = 0;
+		}
+	} else {
+		percpu_counter_inc(&stats->es_stats_cache_misses);
+	}
+
+	read_unlock(&EXT4_I(inode)->i_es_lock);
+
+	trace_ext4_es_lookup_extent_exit(inode, es, found);
+	return found;
+}
+
+struct rsvd_count {
+	int ndelonly;
+	bool first_do_lblk_found;
+	ext4_lblk_t first_do_lblk;
+	ext4_lblk_t last_do_lblk;
+	struct extent_status *left_es;
+	bool partial;
+	ext4_lblk_t lclu;
+};
+
+/*
+ * init_rsvd - initialize reserved count data before removing block range
+ *	       in file from extent status tree
+ *
+ * @inode - file containing range
+ * @lblk - first block in range
+ * @es - pointer to first extent in range
+ * @rc - pointer to reserved count data
+ *
+ * Assumes es is not NULL
+ */
+static void init_rsvd(struct inode *inode, ext4_lblk_t lblk,
+		      struct extent_status *es, struct rsvd_count *rc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct rb_node *node;
+
+	rc->ndelonly = 0;
+
+	/*
+	 * for bigalloc, note the first delonly block in the range has not
+	 * been found, record the extent containing the block to the left of
+	 * the region to be removed, if any, and note that there's no partial
+	 * cluster to track
+	 */
+	if (sbi->s_cluster_ratio > 1) {
+		rc->first_do_lblk_found = false;
+		if (lblk > es->es_lblk) {
+			rc->left_es = es;
+		} else {
+			node = rb_prev(&es->rb_node);
+			rc->left_es = node ? rb_entry(node,
+						      struct extent_status,
+						      rb_node) : NULL;
+		}
+		rc->partial = false;
+	}
+}
+
+/*
+ * count_rsvd - count the clusters containing delayed and not unwritten
+ *		(delonly) blocks in a range within an extent and add to
+ *	        the running tally in rsvd_count
+ *
+ * @inode - file containing extent
+ * @lblk - first block in range
+ * @len - length of range in blocks
+ * @es - pointer to extent containing clusters to be counted
+ * @rc - pointer to reserved count data
+ *
+ * Tracks partial clusters found at the beginning and end of extents so
+ * they aren't overcounted when they span adjacent extents
+ */
+static void count_rsvd(struct inode *inode, ext4_lblk_t lblk, long len,
+		       struct extent_status *es, struct rsvd_count *rc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	ext4_lblk_t i, end, nclu;
+
+	if (!ext4_es_is_delonly(es))
+		return;
+
+	WARN_ON(len <= 0);
+
+	if (sbi->s_cluster_ratio == 1) {
+		rc->ndelonly += (int) len;
+		return;
+	}
+
+	/* bigalloc */
+
+	i = (lblk < es->es_lblk) ? es->es_lblk : lblk;
+	end = lblk + (ext4_lblk_t) len - 1;
+	end = (end > ext4_es_end(es)) ? ext4_es_end(es) : end;
+
+	/* record the first block of the first delonly extent seen */
+	if (!rc->first_do_lblk_found) {
+		rc->first_do_lblk = i;
+		rc->first_do_lblk_found = true;
+	}
+
+	/* update the last lblk in the region seen so far */
+	rc->last_do_lblk = end;
+
+	/*
+	 * if we're tracking a partial cluster and the current extent
+	 * doesn't start with it, count it and stop tracking
+	 */
+	if (rc->partial && (rc->lclu != EXT4_B2C(sbi, i))) {
+		rc->ndelonly++;
+		rc->partial = false;
+	}
+
+	/*
+	 * if the first cluster doesn't start on a cluster boundary but
+	 * ends on one, count it
+	 */
+	if (EXT4_LBLK_COFF(sbi, i) != 0) {
+		if (end >= EXT4_LBLK_CFILL(sbi, i)) {
+			rc->ndelonly++;
+			rc->partial = false;
+			i = EXT4_LBLK_CFILL(sbi, i) + 1;
+		}
+	}
+
+	/*
+	 * if the current cluster starts on a cluster boundary, count the
+	 * number of whole delonly clusters in the extent
+	 */
+	if ((i + sbi->s_cluster_ratio - 1) <= end) {
+		nclu = (end - i + 1) >> sbi->s_cluster_bits;
+		rc->ndelonly += nclu;
+		i += nclu << sbi->s_cluster_bits;
+	}
+
+	/*
+	 * start tracking a partial cluster if there's a partial at the end
+	 * of the current extent and we're not already tracking one
+	 */
+	if (!rc->partial && i <= end) {
+		rc->partial = true;
+		rc->lclu = EXT4_B2C(sbi, i);
+	}
+}
+
+/*
+ * __pr_tree_search - search for a pending cluster reservation
+ *
+ * @root - root of pending reservation tree
+ * @lclu - logical cluster to search for
+ *
+ * Returns the pending reservation for the cluster identified by @lclu
+ * if found.  If not, returns a reservation for the next cluster if any,
+ * and if not, returns NULL.
+ */
+static struct pending_reservation *__pr_tree_search(struct rb_root *root,
+						    ext4_lblk_t lclu)
+{
+	struct rb_node *node = root->rb_node;
+	struct pending_reservation *pr = NULL;
+
+	while (node) {
+		pr = rb_entry(node, struct pending_reservation, rb_node);
+		if (lclu < pr->lclu)
+			node = node->rb_left;
+		else if (lclu > pr->lclu)
+			node = node->rb_right;
+		else
+			return pr;
+	}
+	if (pr && lclu < pr->lclu)
+		return pr;
+	if (pr && lclu > pr->lclu) {
+		node = rb_next(&pr->rb_node);
+		return node ? rb_entry(node, struct pending_reservation,
+				       rb_node) : NULL;
+	}
+	return NULL;
+}
+
+/*
+ * get_rsvd - calculates and returns the number of cluster reservations to be
+ *	      released when removing a block range from the extent status tree
+ *	      and releases any pending reservations within the range
+ *
+ * @inode - file containing block range
+ * @end - last block in range
+ * @right_es - pointer to extent containing next block beyond end or NULL
+ * @rc - pointer to reserved count data
+ *
+ * The number of reservations to be released is equal to the number of
+ * clusters containing delayed and not unwritten (delonly) blocks within
+ * the range, minus the number of clusters still containing delonly blocks
+ * at the ends of the range, and minus the number of pending reservations
+ * within the range.
+ */
+static unsigned int get_rsvd(struct inode *inode, ext4_lblk_t end,
+			     struct extent_status *right_es,
+			     struct rsvd_count *rc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct pending_reservation *pr;
+	struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree;
+	struct rb_node *node;
+	ext4_lblk_t first_lclu, last_lclu;
+	bool left_delonly, right_delonly, count_pending;
+	struct extent_status *es;
+
+	if (sbi->s_cluster_ratio > 1) {
+		/* count any remaining partial cluster */
+		if (rc->partial)
+			rc->ndelonly++;
+
+		if (rc->ndelonly == 0)
+			return 0;
+
+		first_lclu = EXT4_B2C(sbi, rc->first_do_lblk);
+		last_lclu = EXT4_B2C(sbi, rc->last_do_lblk);
+
+		/*
+		 * decrease the delonly count by the number of clusters at the
+		 * ends of the range that still contain delonly blocks -
+		 * these clusters still need to be reserved
+		 */
+		left_delonly = right_delonly = false;
+
+		es = rc->left_es;
+		while (es && ext4_es_end(es) >=
+		       EXT4_LBLK_CMASK(sbi, rc->first_do_lblk)) {
+			if (ext4_es_is_delonly(es)) {
+				rc->ndelonly--;
+				left_delonly = true;
+				break;
+			}
+			node = rb_prev(&es->rb_node);
+			if (!node)
+				break;
+			es = rb_entry(node, struct extent_status, rb_node);
+		}
+		if (right_es && (!left_delonly || first_lclu != last_lclu)) {
+			if (end < ext4_es_end(right_es)) {
+				es = right_es;
+			} else {
+				node = rb_next(&right_es->rb_node);
+				es = node ? rb_entry(node, struct extent_status,
+						     rb_node) : NULL;
+			}
+			while (es && es->es_lblk <=
+			       EXT4_LBLK_CFILL(sbi, rc->last_do_lblk)) {
+				if (ext4_es_is_delonly(es)) {
+					rc->ndelonly--;
+					right_delonly = true;
+					break;
+				}
+				node = rb_next(&es->rb_node);
+				if (!node)
+					break;
+				es = rb_entry(node, struct extent_status,
+					      rb_node);
+			}
+		}
+
+		/*
+		 * Determine the block range that should be searched for
+		 * pending reservations, if any.  Clusters on the ends of the
+		 * original removed range containing delonly blocks are
+		 * excluded.  They've already been accounted for and it's not
+		 * possible to determine if an associated pending reservation
+		 * should be released with the information available in the
+		 * extents status tree.
+		 */
+		if (first_lclu == last_lclu) {
+			if (left_delonly | right_delonly)
+				count_pending = false;
+			else
+				count_pending = true;
+		} else {
+			if (left_delonly)
+				first_lclu++;
+			if (right_delonly)
+				last_lclu--;
+			if (first_lclu <= last_lclu)
+				count_pending = true;
+			else
+				count_pending = false;
+		}
+
+		/*
+		 * a pending reservation found between first_lclu and last_lclu
+		 * represents an allocated cluster that contained at least one
+		 * delonly block, so the delonly total must be reduced by one
+		 * for each pending reservation found and released
+		 */
+		if (count_pending) {
+			pr = __pr_tree_search(&tree->root, first_lclu);
+			while (pr && pr->lclu <= last_lclu) {
+				rc->ndelonly--;
+				node = rb_next(&pr->rb_node);
+				rb_erase(&pr->rb_node, &tree->root);
+				__free_pending(pr);
+				if (!node)
+					break;
+				pr = rb_entry(node, struct pending_reservation,
+					      rb_node);
+			}
+		}
+	}
+	return rc->ndelonly;
+}
+
+
+/*
+ * __es_remove_extent - removes block range from extent status tree
+ *
+ * @inode - file containing range
+ * @lblk - first block in range
+ * @end - last block in range
+ * @reserved - number of cluster reservations released
+ * @prealloc - pre-allocated es to avoid memory allocation failures
+ *
+ * If @reserved is not NULL and delayed allocation is enabled, counts
+ * block/cluster reservations freed by removing range and if bigalloc
+ * enabled cancels pending reservations as needed. Returns 0 on success,
+ * error code on failure.
+ */
+static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
+			      ext4_lblk_t end, int *reserved,
+			      struct extent_status *prealloc)
+{
+	struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
+	struct rb_node *node;
+	struct extent_status *es;
+	struct extent_status orig_es;
+	ext4_lblk_t len1, len2;
+	ext4_fsblk_t block;
+	int err = 0;
+	bool count_reserved = true;
+	struct rsvd_count rc;
+
+	if (reserved == NULL || !test_opt(inode->i_sb, DELALLOC))
+		count_reserved = false;
+
+	es = __es_tree_search(&tree->root, lblk);
+	if (!es)
+		goto out;
+	if (es->es_lblk > end)
+		goto out;
+
+	/* Simply invalidate cache_es. */
+	tree->cache_es = NULL;
+	if (count_reserved)
+		init_rsvd(inode, lblk, es, &rc);
+
+	orig_es.es_lblk = es->es_lblk;
+	orig_es.es_len = es->es_len;
+	orig_es.es_pblk = es->es_pblk;
+
+	len1 = lblk > es->es_lblk ? lblk - es->es_lblk : 0;
+	len2 = ext4_es_end(es) > end ? ext4_es_end(es) - end : 0;
+	if (len1 > 0)
+		es->es_len = len1;
+	if (len2 > 0) {
+		if (len1 > 0) {
+			struct extent_status newes;
+
+			newes.es_lblk = end + 1;
+			newes.es_len = len2;
+			block = 0x7FDEADBEEFULL;
+			if (ext4_es_is_written(&orig_es) ||
+			    ext4_es_is_unwritten(&orig_es))
+				block = ext4_es_pblock(&orig_es) +
+					orig_es.es_len - len2;
+			ext4_es_store_pblock_status(&newes, block,
+						    ext4_es_status(&orig_es));
+			err = __es_insert_extent(inode, &newes, prealloc);
+			if (err) {
+				if (!ext4_es_must_keep(&newes))
+					return 0;
+
+				es->es_lblk = orig_es.es_lblk;
+				es->es_len = orig_es.es_len;
+				goto out;
+			}
+		} else {
+			es->es_lblk = end + 1;
+			es->es_len = len2;
+			if (ext4_es_is_written(es) ||
+			    ext4_es_is_unwritten(es)) {
+				block = orig_es.es_pblk + orig_es.es_len - len2;
+				ext4_es_store_pblock(es, block);
+			}
+		}
+		if (count_reserved)
+			count_rsvd(inode, orig_es.es_lblk + len1,
+				   orig_es.es_len - len1 - len2, &orig_es, &rc);
+		goto out_get_reserved;
+	}
+
+	if (len1 > 0) {
+		if (count_reserved)
+			count_rsvd(inode, lblk, orig_es.es_len - len1,
+				   &orig_es, &rc);
+		node = rb_next(&es->rb_node);
+		if (node)
+			es = rb_entry(node, struct extent_status, rb_node);
+		else
+			es = NULL;
+	}
+
+	while (es && ext4_es_end(es) <= end) {
+		if (count_reserved)
+			count_rsvd(inode, es->es_lblk, es->es_len, es, &rc);
+		node = rb_next(&es->rb_node);
+		rb_erase(&es->rb_node, &tree->root);
+		ext4_es_free_extent(inode, es);
+		if (!node) {
+			es = NULL;
+			break;
+		}
+		es = rb_entry(node, struct extent_status, rb_node);
+	}
+
+	if (es && es->es_lblk < end + 1) {
+		ext4_lblk_t orig_len = es->es_len;
+
+		len1 = ext4_es_end(es) - end;
+		if (count_reserved)
+			count_rsvd(inode, es->es_lblk, orig_len - len1,
+				   es, &rc);
+		es->es_lblk = end + 1;
+		es->es_len = len1;
+		if (ext4_es_is_written(es) || ext4_es_is_unwritten(es)) {
+			block = es->es_pblk + orig_len - len1;
+			ext4_es_store_pblock(es, block);
+		}
+	}
+
+out_get_reserved:
+	if (count_reserved)
+		*reserved = get_rsvd(inode, end, es, &rc);
+out:
+	return err;
+}
+
+/*
+ * ext4_es_remove_extent - removes block range from extent status tree
+ *
+ * @inode - file containing range
+ * @lblk - first block in range
+ * @len - number of blocks to remove
+ *
+ * Reduces block/cluster reservation count and for bigalloc cancels pending
+ * reservations as needed. Returns 0 on success, error code on failure.
+ */
+int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
+			  ext4_lblk_t len)
+{
+	ext4_lblk_t end;
+	int err = 0;
+	int reserved = 0;
+	struct extent_status *es = NULL;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	trace_ext4_es_remove_extent(inode, lblk, len);
+	es_debug("remove [%u/%u) from extent status tree of inode %lu\n",
+		 lblk, len, inode->i_ino);
+
+	if (!len)
+		return err;
+
+	end = lblk + len - 1;
+	BUG_ON(end < lblk);
+
+retry:
+	if (err && !es)
+		es = __es_alloc_extent(true);
+	/*
+	 * ext4_clear_inode() depends on us taking i_es_lock unconditionally
+	 * so that we are sure __es_shrink() is done with the inode before it
+	 * is reclaimed.
+	 */
+	write_lock(&EXT4_I(inode)->i_es_lock);
+	err = __es_remove_extent(inode, lblk, end, &reserved, es);
+	/* Free preallocated extent if it didn't get used. */
+	if (es) {
+		if (!es->es_len)
+			__es_free_extent(es);
+		es = NULL;
+	}
+	write_unlock(&EXT4_I(inode)->i_es_lock);
+	if (err)
+		goto retry;
+
+	ext4_es_print_tree(inode);
+	ext4_da_release_space(inode, reserved);
+	return 0;
+}
+
+static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan,
+		       struct ext4_inode_info *locked_ei)
+{
+	struct ext4_inode_info *ei;
+	struct ext4_es_stats *es_stats;
+	ktime_t start_time;
+	u64 scan_time;
+	int nr_to_walk;
+	int nr_shrunk = 0;
+	int retried = 0, nr_skipped = 0;
+
+	es_stats = &sbi->s_es_stats;
+	start_time = ktime_get();
+
+retry:
+	spin_lock(&sbi->s_es_lock);
+	nr_to_walk = sbi->s_es_nr_inode;
+	while (nr_to_walk-- > 0) {
+		if (list_empty(&sbi->s_es_list)) {
+			spin_unlock(&sbi->s_es_lock);
+			goto out;
+		}
+		ei = list_first_entry(&sbi->s_es_list, struct ext4_inode_info,
+				      i_es_list);
+		/* Move the inode to the tail */
+		list_move_tail(&ei->i_es_list, &sbi->s_es_list);
+
+		/*
+		 * Normally we try hard to avoid shrinking precached inodes,
+		 * but we will as a last resort.
+		 */
+		if (!retried && ext4_test_inode_state(&ei->vfs_inode,
+						EXT4_STATE_EXT_PRECACHED)) {
+			nr_skipped++;
+			continue;
+		}
+
+		if (ei == locked_ei || !write_trylock(&ei->i_es_lock)) {
+			nr_skipped++;
+			continue;
+		}
+		/*
+		 * Now we hold i_es_lock which protects us from inode reclaim
+		 * freeing inode under us
+		 */
+		spin_unlock(&sbi->s_es_lock);
+
+		nr_shrunk += es_reclaim_extents(ei, &nr_to_scan);
+		write_unlock(&ei->i_es_lock);
+
+		if (nr_to_scan <= 0)
+			goto out;
+		spin_lock(&sbi->s_es_lock);
+	}
+	spin_unlock(&sbi->s_es_lock);
+
+	/*
+	 * If we skipped any inodes, and we weren't able to make any
+	 * forward progress, try again to scan precached inodes.
+	 */
+	if ((nr_shrunk == 0) && nr_skipped && !retried) {
+		retried++;
+		goto retry;
+	}
+
+	if (locked_ei && nr_shrunk == 0)
+		nr_shrunk = es_reclaim_extents(locked_ei, &nr_to_scan);
+
+out:
+	scan_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
+	if (likely(es_stats->es_stats_scan_time))
+		es_stats->es_stats_scan_time = (scan_time +
+				es_stats->es_stats_scan_time*3) / 4;
+	else
+		es_stats->es_stats_scan_time = scan_time;
+	if (scan_time > es_stats->es_stats_max_scan_time)
+		es_stats->es_stats_max_scan_time = scan_time;
+	if (likely(es_stats->es_stats_shrunk))
+		es_stats->es_stats_shrunk = (nr_shrunk +
+				es_stats->es_stats_shrunk*3) / 4;
+	else
+		es_stats->es_stats_shrunk = nr_shrunk;
+
+	trace_ext4_es_shrink(sbi->s_sb, nr_shrunk, scan_time,
+			     nr_skipped, retried);
+	return nr_shrunk;
+}
+
+static unsigned long ext4_es_count(struct shrinker *shrink,
+				   struct shrink_control *sc)
+{
+	unsigned long nr;
+	struct ext4_sb_info *sbi;
+
+	sbi = container_of(shrink, struct ext4_sb_info, s_es_shrinker);
+	nr = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
+	trace_ext4_es_shrink_count(sbi->s_sb, sc->nr_to_scan, nr);
+	return nr;
+}
+
+static unsigned long ext4_es_scan(struct shrinker *shrink,
+				  struct shrink_control *sc)
+{
+	struct ext4_sb_info *sbi = container_of(shrink,
+					struct ext4_sb_info, s_es_shrinker);
+	int nr_to_scan = sc->nr_to_scan;
+	int ret, nr_shrunk;
+
+	ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
+	trace_ext4_es_shrink_scan_enter(sbi->s_sb, nr_to_scan, ret);
+
+	nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
+
+	ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
+	trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
+	return nr_shrunk;
+}
+
+int ext4_seq_es_shrinker_info_show(struct seq_file *seq, void *v)
+{
+	struct ext4_sb_info *sbi = EXT4_SB((struct super_block *) seq->private);
+	struct ext4_es_stats *es_stats = &sbi->s_es_stats;
+	struct ext4_inode_info *ei, *max = NULL;
+	unsigned int inode_cnt = 0;
+
+	if (v != SEQ_START_TOKEN)
+		return 0;
+
+	/* here we just find an inode that has the max nr. of objects */
+	spin_lock(&sbi->s_es_lock);
+	list_for_each_entry(ei, &sbi->s_es_list, i_es_list) {
+		inode_cnt++;
+		if (max && max->i_es_all_nr < ei->i_es_all_nr)
+			max = ei;
+		else if (!max)
+			max = ei;
+	}
+	spin_unlock(&sbi->s_es_lock);
+
+	seq_printf(seq, "stats:\n  %lld objects\n  %lld reclaimable objects\n",
+		   percpu_counter_sum_positive(&es_stats->es_stats_all_cnt),
+		   percpu_counter_sum_positive(&es_stats->es_stats_shk_cnt));
+	seq_printf(seq, "  %lld/%lld cache hits/misses\n",
+		   percpu_counter_sum_positive(&es_stats->es_stats_cache_hits),
+		   percpu_counter_sum_positive(&es_stats->es_stats_cache_misses));
+	if (inode_cnt)
+		seq_printf(seq, "  %d inodes on list\n", inode_cnt);
+
+	seq_printf(seq, "average:\n  %llu us scan time\n",
+	    div_u64(es_stats->es_stats_scan_time, 1000));
+	seq_printf(seq, "  %lu shrunk objects\n", es_stats->es_stats_shrunk);
+	if (inode_cnt)
+		seq_printf(seq,
+		    "maximum:\n  %lu inode (%u objects, %u reclaimable)\n"
+		    "  %llu us max scan time\n",
+		    max->vfs_inode.i_ino, max->i_es_all_nr, max->i_es_shk_nr,
+		    div_u64(es_stats->es_stats_max_scan_time, 1000));
+
+	return 0;
+}
+
+int ext4_es_register_shrinker(struct ext4_sb_info *sbi)
+{
+	int err;
+
+	/* Make sure we have enough bits for physical block number */
+	BUILD_BUG_ON(ES_SHIFT < 48);
+	INIT_LIST_HEAD(&sbi->s_es_list);
+	sbi->s_es_nr_inode = 0;
+	spin_lock_init(&sbi->s_es_lock);
+	sbi->s_es_stats.es_stats_shrunk = 0;
+	err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_hits, 0,
+				  GFP_KERNEL);
+	if (err)
+		return err;
+	err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_misses, 0,
+				  GFP_KERNEL);
+	if (err)
+		goto err1;
+	sbi->s_es_stats.es_stats_scan_time = 0;
+	sbi->s_es_stats.es_stats_max_scan_time = 0;
+	err = percpu_counter_init(&sbi->s_es_stats.es_stats_all_cnt, 0, GFP_KERNEL);
+	if (err)
+		goto err2;
+	err = percpu_counter_init(&sbi->s_es_stats.es_stats_shk_cnt, 0, GFP_KERNEL);
+	if (err)
+		goto err3;
+
+	sbi->s_es_shrinker.scan_objects = ext4_es_scan;
+	sbi->s_es_shrinker.count_objects = ext4_es_count;
+	sbi->s_es_shrinker.seeks = DEFAULT_SEEKS;
+	err = register_shrinker(&sbi->s_es_shrinker);
+	if (err)
+		goto err4;
+
+	return 0;
+err4:
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt);
+err3:
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt);
+err2:
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses);
+err1:
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits);
+	return err;
+}
+
+void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi)
+{
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits);
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses);
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt);
+	percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt);
+	unregister_shrinker(&sbi->s_es_shrinker);
+}
+
+/*
+ * Shrink extents in given inode from ei->i_es_shrink_lblk till end. Scan at
+ * most *nr_to_scan extents, update *nr_to_scan accordingly.
+ *
+ * Return 0 if we hit end of tree / interval, 1 if we exhausted nr_to_scan.
+ * Increment *nr_shrunk by the number of reclaimed extents. Also update
+ * ei->i_es_shrink_lblk to where we should continue scanning.
+ */
+static int es_do_reclaim_extents(struct ext4_inode_info *ei, ext4_lblk_t end,
+				 int *nr_to_scan, int *nr_shrunk)
+{
+	struct inode *inode = &ei->vfs_inode;
+	struct ext4_es_tree *tree = &ei->i_es_tree;
+	struct extent_status *es;
+	struct rb_node *node;
+
+	es = __es_tree_search(&tree->root, ei->i_es_shrink_lblk);
+	if (!es)
+		goto out_wrap;
+
+	while (*nr_to_scan > 0) {
+		if (es->es_lblk > end) {
+			ei->i_es_shrink_lblk = end + 1;
+			return 0;
+		}
+
+		(*nr_to_scan)--;
+		node = rb_next(&es->rb_node);
+
+		if (ext4_es_must_keep(es))
+			goto next;
+		if (ext4_es_is_referenced(es)) {
+			ext4_es_clear_referenced(es);
+			goto next;
+		}
+
+		rb_erase(&es->rb_node, &tree->root);
+		ext4_es_free_extent(inode, es);
+		(*nr_shrunk)++;
+next:
+		if (!node)
+			goto out_wrap;
+		es = rb_entry(node, struct extent_status, rb_node);
+	}
+	ei->i_es_shrink_lblk = es->es_lblk;
+	return 1;
+out_wrap:
+	ei->i_es_shrink_lblk = 0;
+	return 0;
+}
+
+static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan)
+{
+	struct inode *inode = &ei->vfs_inode;
+	int nr_shrunk = 0;
+	ext4_lblk_t start = ei->i_es_shrink_lblk;
+	static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
+				      DEFAULT_RATELIMIT_BURST);
+
+	if (ei->i_es_shk_nr == 0)
+		return 0;
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_EXT_PRECACHED) &&
+	    __ratelimit(&_rs))
+		ext4_warning(inode->i_sb, "forced shrink of precached extents");
+
+	if (!es_do_reclaim_extents(ei, EXT_MAX_BLOCKS, nr_to_scan, &nr_shrunk) &&
+	    start != 0)
+		es_do_reclaim_extents(ei, start - 1, nr_to_scan, &nr_shrunk);
+
+	ei->i_es_tree.cache_es = NULL;
+	return nr_shrunk;
+}
+
+/*
+ * Called to support EXT4_IOC_CLEAR_ES_CACHE.  We can only remove
+ * discretionary entries from the extent status cache.  (Some entries
+ * must be present for proper operations.)
+ */
+void ext4_clear_inode_es(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct extent_status *es;
+	struct ext4_es_tree *tree;
+	struct rb_node *node;
+
+	write_lock(&ei->i_es_lock);
+	tree = &EXT4_I(inode)->i_es_tree;
+	tree->cache_es = NULL;
+	node = rb_first(&tree->root);
+	while (node) {
+		es = rb_entry(node, struct extent_status, rb_node);
+		node = rb_next(node);
+		if (!ext4_es_must_keep(es)) {
+			rb_erase(&es->rb_node, &tree->root);
+			ext4_es_free_extent(inode, es);
+		}
+	}
+	ext4_clear_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
+	write_unlock(&ei->i_es_lock);
+}
+
+#ifdef ES_DEBUG__
+static void ext4_print_pending_tree(struct inode *inode)
+{
+	struct ext4_pending_tree *tree;
+	struct rb_node *node;
+	struct pending_reservation *pr;
+
+	printk(KERN_DEBUG "pending reservations for inode %lu:", inode->i_ino);
+	tree = &EXT4_I(inode)->i_pending_tree;
+	node = rb_first(&tree->root);
+	while (node) {
+		pr = rb_entry(node, struct pending_reservation, rb_node);
+		printk(KERN_DEBUG " %u", pr->lclu);
+		node = rb_next(node);
+	}
+	printk(KERN_DEBUG "\n");
+}
+#else
+#define ext4_print_pending_tree(inode)
+#endif
+
+int __init ext4_init_pending(void)
+{
+	ext4_pending_cachep = kmem_cache_create("ext4_pending_reservation",
+					   sizeof(struct pending_reservation),
+					   0, (SLAB_RECLAIM_ACCOUNT), NULL);
+	if (ext4_pending_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+void ext4_exit_pending(void)
+{
+	kmem_cache_destroy(ext4_pending_cachep);
+}
+
+void ext4_init_pending_tree(struct ext4_pending_tree *tree)
+{
+	tree->root = RB_ROOT;
+}
+
+/*
+ * __get_pending - retrieve a pointer to a pending reservation
+ *
+ * @inode - file containing the pending cluster reservation
+ * @lclu - logical cluster of interest
+ *
+ * Returns a pointer to a pending reservation if it's a member of
+ * the set, and NULL if not.  Must be called holding i_es_lock.
+ */
+static struct pending_reservation *__get_pending(struct inode *inode,
+						 ext4_lblk_t lclu)
+{
+	struct ext4_pending_tree *tree;
+	struct rb_node *node;
+	struct pending_reservation *pr = NULL;
+
+	tree = &EXT4_I(inode)->i_pending_tree;
+	node = (&tree->root)->rb_node;
+
+	while (node) {
+		pr = rb_entry(node, struct pending_reservation, rb_node);
+		if (lclu < pr->lclu)
+			node = node->rb_left;
+		else if (lclu > pr->lclu)
+			node = node->rb_right;
+		else if (lclu == pr->lclu)
+			return pr;
+	}
+	return NULL;
+}
+
+/*
+ * __insert_pending - adds a pending cluster reservation to the set of
+ *                    pending reservations
+ *
+ * @inode - file containing the cluster
+ * @lblk - logical block in the cluster to be added
+ * @prealloc - preallocated pending entry
+ *
+ * Returns 0 on successful insertion and -ENOMEM on failure.  If the
+ * pending reservation is already in the set, returns successfully.
+ */
+static int __insert_pending(struct inode *inode, ext4_lblk_t lblk,
+			    struct pending_reservation **prealloc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree;
+	struct rb_node **p = &tree->root.rb_node;
+	struct rb_node *parent = NULL;
+	struct pending_reservation *pr;
+	ext4_lblk_t lclu;
+	int ret = 0;
+
+	lclu = EXT4_B2C(sbi, lblk);
+	/* search to find parent for insertion */
+	while (*p) {
+		parent = *p;
+		pr = rb_entry(parent, struct pending_reservation, rb_node);
+
+		if (lclu < pr->lclu) {
+			p = &(*p)->rb_left;
+		} else if (lclu > pr->lclu) {
+			p = &(*p)->rb_right;
+		} else {
+			/* pending reservation already inserted */
+			goto out;
+		}
+	}
+
+	if (likely(*prealloc == NULL)) {
+		pr = __alloc_pending(false);
+		if (!pr) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else {
+		pr = *prealloc;
+		*prealloc = NULL;
+	}
+	pr->lclu = lclu;
+
+	rb_link_node(&pr->rb_node, parent, p);
+	rb_insert_color(&pr->rb_node, &tree->root);
+
+out:
+	return ret;
+}
+
+/*
+ * __remove_pending - removes a pending cluster reservation from the set
+ *                    of pending reservations
+ *
+ * @inode - file containing the cluster
+ * @lblk - logical block in the pending cluster reservation to be removed
+ *
+ * Returns successfully if pending reservation is not a member of the set.
+ */
+static void __remove_pending(struct inode *inode, ext4_lblk_t lblk)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct pending_reservation *pr;
+	struct ext4_pending_tree *tree;
+
+	pr = __get_pending(inode, EXT4_B2C(sbi, lblk));
+	if (pr != NULL) {
+		tree = &EXT4_I(inode)->i_pending_tree;
+		rb_erase(&pr->rb_node, &tree->root);
+		__free_pending(pr);
+	}
+}
+
+/*
+ * ext4_remove_pending - removes a pending cluster reservation from the set
+ *                       of pending reservations
+ *
+ * @inode - file containing the cluster
+ * @lblk - logical block in the pending cluster reservation to be removed
+ *
+ * Locking for external use of __remove_pending.
+ */
+void ext4_remove_pending(struct inode *inode, ext4_lblk_t lblk)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	write_lock(&ei->i_es_lock);
+	__remove_pending(inode, lblk);
+	write_unlock(&ei->i_es_lock);
+}
+
+/*
+ * ext4_is_pending - determine whether a cluster has a pending reservation
+ *                   on it
+ *
+ * @inode - file containing the cluster
+ * @lblk - logical block in the cluster
+ *
+ * Returns true if there's a pending reservation for the cluster in the
+ * set of pending reservations, and false if not.
+ */
+bool ext4_is_pending(struct inode *inode, ext4_lblk_t lblk)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	bool ret;
+
+	read_lock(&ei->i_es_lock);
+	ret = (bool)(__get_pending(inode, EXT4_B2C(sbi, lblk)) != NULL);
+	read_unlock(&ei->i_es_lock);
+
+	return ret;
+}
+
+/*
+ * ext4_es_insert_delayed_block - adds a delayed block to the extents status
+ *                                tree, adding a pending reservation where
+ *                                needed
+ *
+ * @inode - file containing the newly added block
+ * @lblk - logical block to be added
+ * @allocated - indicates whether a physical cluster has been allocated for
+ *              the logical cluster that contains the block
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
+				 bool allocated)
+{
+	struct extent_status newes;
+	int err1 = 0, err2 = 0, err3 = 0;
+	struct extent_status *es1 = NULL;
+	struct extent_status *es2 = NULL;
+	struct pending_reservation *pr = NULL;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	es_debug("add [%u/1) delayed to extent status tree of inode %lu\n",
+		 lblk, inode->i_ino);
+
+	newes.es_lblk = lblk;
+	newes.es_len = 1;
+	ext4_es_store_pblock_status(&newes, ~0, EXTENT_STATUS_DELAYED);
+	trace_ext4_es_insert_delayed_block(inode, &newes, allocated);
+
+	ext4_es_insert_extent_check(inode, &newes);
+
+retry:
+	if (err1 && !es1)
+		es1 = __es_alloc_extent(true);
+	if ((err1 || err2) && !es2)
+		es2 = __es_alloc_extent(true);
+	if ((err1 || err2 || err3) && allocated && !pr)
+		pr = __alloc_pending(true);
+	write_lock(&EXT4_I(inode)->i_es_lock);
+
+	err1 = __es_remove_extent(inode, lblk, lblk, NULL, es1);
+	if (err1 != 0)
+		goto error;
+	/* Free preallocated extent if it didn't get used. */
+	if (es1) {
+		if (!es1->es_len)
+			__es_free_extent(es1);
+		es1 = NULL;
+	}
+
+	err2 = __es_insert_extent(inode, &newes, es2);
+	if (err2 != 0)
+		goto error;
+	/* Free preallocated extent if it didn't get used. */
+	if (es2) {
+		if (!es2->es_len)
+			__es_free_extent(es2);
+		es2 = NULL;
+	}
+
+	if (allocated) {
+		err3 = __insert_pending(inode, lblk, &pr);
+		if (err3 != 0)
+			goto error;
+		if (pr) {
+			__free_pending(pr);
+			pr = NULL;
+		}
+	}
+error:
+	write_unlock(&EXT4_I(inode)->i_es_lock);
+	if (err1 || err2 || err3)
+		goto retry;
+
+	ext4_es_print_tree(inode);
+	ext4_print_pending_tree(inode);
+	return 0;
+}
+
+/*
+ * __es_delayed_clu - count number of clusters containing blocks that
+ *                    are delayed only
+ *
+ * @inode - file containing block range
+ * @start - logical block defining start of range
+ * @end - logical block defining end of range
+ *
+ * Returns the number of clusters containing only delayed (not delayed
+ * and unwritten) blocks in the range specified by @start and @end.  Any
+ * cluster or part of a cluster within the range and containing a delayed
+ * and not unwritten block within the range is counted as a whole cluster.
+ */
+static unsigned int __es_delayed_clu(struct inode *inode, ext4_lblk_t start,
+				     ext4_lblk_t end)
+{
+	struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
+	struct extent_status *es;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct rb_node *node;
+	ext4_lblk_t first_lclu, last_lclu;
+	unsigned long long last_counted_lclu;
+	unsigned int n = 0;
+
+	/* guaranteed to be unequal to any ext4_lblk_t value */
+	last_counted_lclu = ~0ULL;
+
+	es = __es_tree_search(&tree->root, start);
+
+	while (es && (es->es_lblk <= end)) {
+		if (ext4_es_is_delonly(es)) {
+			if (es->es_lblk <= start)
+				first_lclu = EXT4_B2C(sbi, start);
+			else
+				first_lclu = EXT4_B2C(sbi, es->es_lblk);
+
+			if (ext4_es_end(es) >= end)
+				last_lclu = EXT4_B2C(sbi, end);
+			else
+				last_lclu = EXT4_B2C(sbi, ext4_es_end(es));
+
+			if (first_lclu == last_counted_lclu)
+				n += last_lclu - first_lclu;
+			else
+				n += last_lclu - first_lclu + 1;
+			last_counted_lclu = last_lclu;
+		}
+		node = rb_next(&es->rb_node);
+		if (!node)
+			break;
+		es = rb_entry(node, struct extent_status, rb_node);
+	}
+
+	return n;
+}
+
+/*
+ * ext4_es_delayed_clu - count number of clusters containing blocks that
+ *                       are both delayed and unwritten
+ *
+ * @inode - file containing block range
+ * @lblk - logical block defining start of range
+ * @len - number of blocks in range
+ *
+ * Locking for external use of __es_delayed_clu().
+ */
+unsigned int ext4_es_delayed_clu(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t len)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	ext4_lblk_t end;
+	unsigned int n;
+
+	if (len == 0)
+		return 0;
+
+	end = lblk + len - 1;
+	WARN_ON(end < lblk);
+
+	read_lock(&ei->i_es_lock);
+
+	n = __es_delayed_clu(inode, lblk, end);
+
+	read_unlock(&ei->i_es_lock);
+
+	return n;
+}
+
+/*
+ * __revise_pending - makes, cancels, or leaves unchanged pending cluster
+ *                    reservations for a specified block range depending
+ *                    upon the presence or absence of delayed blocks
+ *                    outside the range within clusters at the ends of the
+ *                    range
+ *
+ * @inode - file containing the range
+ * @lblk - logical block defining the start of range
+ * @len  - length of range in blocks
+ * @prealloc - preallocated pending entry
+ *
+ * Used after a newly allocated extent is added to the extents status tree.
+ * Requires that the extents in the range have either written or unwritten
+ * status.  Must be called while holding i_es_lock.
+ */
+static int __revise_pending(struct inode *inode, ext4_lblk_t lblk,
+			    ext4_lblk_t len,
+			    struct pending_reservation **prealloc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	ext4_lblk_t end = lblk + len - 1;
+	ext4_lblk_t first, last;
+	bool f_del = false, l_del = false;
+	int ret = 0;
+
+	if (len == 0)
+		return 0;
+
+	/*
+	 * Two cases - block range within single cluster and block range
+	 * spanning two or more clusters.  Note that a cluster belonging
+	 * to a range starting and/or ending on a cluster boundary is treated
+	 * as if it does not contain a delayed extent.  The new range may
+	 * have allocated space for previously delayed blocks out to the
+	 * cluster boundary, requiring that any pre-existing pending
+	 * reservation be canceled.  Because this code only looks at blocks
+	 * outside the range, it should revise pending reservations
+	 * correctly even if the extent represented by the range can't be
+	 * inserted in the extents status tree due to ENOSPC.
+	 */
+
+	if (EXT4_B2C(sbi, lblk) == EXT4_B2C(sbi, end)) {
+		first = EXT4_LBLK_CMASK(sbi, lblk);
+		if (first != lblk)
+			f_del = __es_scan_range(inode, &ext4_es_is_delonly,
+						first, lblk - 1);
+		if (f_del) {
+			ret = __insert_pending(inode, first, prealloc);
+			if (ret < 0)
+				goto out;
+		} else {
+			last = EXT4_LBLK_CMASK(sbi, end) +
+			       sbi->s_cluster_ratio - 1;
+			if (last != end)
+				l_del = __es_scan_range(inode,
+							&ext4_es_is_delonly,
+							end + 1, last);
+			if (l_del) {
+				ret = __insert_pending(inode, last, prealloc);
+				if (ret < 0)
+					goto out;
+			} else
+				__remove_pending(inode, last);
+		}
+	} else {
+		first = EXT4_LBLK_CMASK(sbi, lblk);
+		if (first != lblk)
+			f_del = __es_scan_range(inode, &ext4_es_is_delonly,
+						first, lblk - 1);
+		if (f_del) {
+			ret = __insert_pending(inode, first, prealloc);
+			if (ret < 0)
+				goto out;
+		} else
+			__remove_pending(inode, first);
+
+		last = EXT4_LBLK_CMASK(sbi, end) + sbi->s_cluster_ratio - 1;
+		if (last != end)
+			l_del = __es_scan_range(inode, &ext4_es_is_delonly,
+						end + 1, last);
+		if (l_del) {
+			ret = __insert_pending(inode, last, prealloc);
+			if (ret < 0)
+				goto out;
+		} else
+			__remove_pending(inode, last);
+	}
+out:
+	return ret;
+}
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
new file mode 100644
index 000000000..4ec30a798
--- /dev/null
+++ b/fs/ext4/extents_status.h
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  fs/ext4/extents_status.h
+ *
+ * Written by Yongqiang Yang <xiaoqiangnk@gmail.com>
+ * Modified by
+ *	Allison Henderson <achender@linux.vnet.ibm.com>
+ *	Zheng Liu <wenqing.lz@taobao.com>
+ *
+ */
+
+#ifndef _EXT4_EXTENTS_STATUS_H
+#define _EXT4_EXTENTS_STATUS_H
+
+/*
+ * Turn on ES_DEBUG__ to get lots of info about extent status operations.
+ */
+#ifdef ES_DEBUG__
+#define es_debug(fmt, ...)	printk(fmt, ##__VA_ARGS__)
+#else
+#define es_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+#endif
+
+/*
+ * With ES_AGGRESSIVE_TEST defined, the result of es caching will be
+ * checked with old map_block's result.
+ */
+#define ES_AGGRESSIVE_TEST__
+
+/*
+ * These flags live in the high bits of extent_status.es_pblk
+ */
+enum {
+	ES_WRITTEN_B,
+	ES_UNWRITTEN_B,
+	ES_DELAYED_B,
+	ES_HOLE_B,
+	ES_REFERENCED_B,
+	ES_FLAGS
+};
+
+#define ES_SHIFT (sizeof(ext4_fsblk_t)*8 - ES_FLAGS)
+#define ES_MASK (~((ext4_fsblk_t)0) << ES_SHIFT)
+
+#define EXTENT_STATUS_WRITTEN	(1 << ES_WRITTEN_B)
+#define EXTENT_STATUS_UNWRITTEN (1 << ES_UNWRITTEN_B)
+#define EXTENT_STATUS_DELAYED	(1 << ES_DELAYED_B)
+#define EXTENT_STATUS_HOLE	(1 << ES_HOLE_B)
+#define EXTENT_STATUS_REFERENCED	(1 << ES_REFERENCED_B)
+
+#define ES_TYPE_MASK	((ext4_fsblk_t)(EXTENT_STATUS_WRITTEN | \
+			  EXTENT_STATUS_UNWRITTEN | \
+			  EXTENT_STATUS_DELAYED | \
+			  EXTENT_STATUS_HOLE) << ES_SHIFT)
+
+struct ext4_sb_info;
+struct ext4_extent;
+
+struct extent_status {
+	struct rb_node rb_node;
+	ext4_lblk_t es_lblk;	/* first logical block extent covers */
+	ext4_lblk_t es_len;	/* length of extent in block */
+	ext4_fsblk_t es_pblk;	/* first physical block */
+};
+
+struct ext4_es_tree {
+	struct rb_root root;
+	struct extent_status *cache_es;	/* recently accessed extent */
+};
+
+struct ext4_es_stats {
+	unsigned long es_stats_shrunk;
+	struct percpu_counter es_stats_cache_hits;
+	struct percpu_counter es_stats_cache_misses;
+	u64 es_stats_scan_time;
+	u64 es_stats_max_scan_time;
+	struct percpu_counter es_stats_all_cnt;
+	struct percpu_counter es_stats_shk_cnt;
+};
+
+/*
+ * Pending cluster reservations for bigalloc file systems
+ *
+ * A cluster with a pending reservation is a logical cluster shared by at
+ * least one extent in the extents status tree with delayed and unwritten
+ * status and at least one other written or unwritten extent.  The
+ * reservation is said to be pending because a cluster reservation would
+ * have to be taken in the event all blocks in the cluster shared with
+ * written or unwritten extents were deleted while the delayed and
+ * unwritten blocks remained.
+ *
+ * The set of pending cluster reservations is an auxiliary data structure
+ * used with the extents status tree to implement reserved cluster/block
+ * accounting for bigalloc file systems.  The set is kept in memory and
+ * records all pending cluster reservations.
+ *
+ * Its primary function is to avoid the need to read extents from the
+ * disk when invalidating pages as a result of a truncate, punch hole, or
+ * collapse range operation.  Page invalidation requires a decrease in the
+ * reserved cluster count if it results in the removal of all delayed
+ * and unwritten extents (blocks) from a cluster that is not shared with a
+ * written or unwritten extent, and no decrease otherwise.  Determining
+ * whether the cluster is shared can be done by searching for a pending
+ * reservation on it.
+ *
+ * Secondarily, it provides a potentially faster method for determining
+ * whether the reserved cluster count should be increased when a physical
+ * cluster is deallocated as a result of a truncate, punch hole, or
+ * collapse range operation.  The necessary information is also present
+ * in the extents status tree, but might be more rapidly accessed in
+ * the pending reservation set in many cases due to smaller size.
+ *
+ * The pending cluster reservation set is implemented as a red-black tree
+ * with the goal of minimizing per page search time overhead.
+ */
+
+struct pending_reservation {
+	struct rb_node rb_node;
+	ext4_lblk_t lclu;
+};
+
+struct ext4_pending_tree {
+	struct rb_root root;
+};
+
+extern int __init ext4_init_es(void);
+extern void ext4_exit_es(void);
+extern void ext4_es_init_tree(struct ext4_es_tree *tree);
+
+extern int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t len, ext4_fsblk_t pblk,
+				 unsigned int status);
+extern void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t len, ext4_fsblk_t pblk,
+				 unsigned int status);
+extern int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t len);
+extern void ext4_es_find_extent_range(struct inode *inode,
+				      int (*match_fn)(struct extent_status *es),
+				      ext4_lblk_t lblk, ext4_lblk_t end,
+				      struct extent_status *es);
+extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
+				 ext4_lblk_t *next_lblk,
+				 struct extent_status *es);
+extern bool ext4_es_scan_range(struct inode *inode,
+			       int (*matching_fn)(struct extent_status *es),
+			       ext4_lblk_t lblk, ext4_lblk_t end);
+extern bool ext4_es_scan_clu(struct inode *inode,
+			     int (*matching_fn)(struct extent_status *es),
+			     ext4_lblk_t lblk);
+
+static inline unsigned int ext4_es_status(struct extent_status *es)
+{
+	return es->es_pblk >> ES_SHIFT;
+}
+
+static inline unsigned int ext4_es_type(struct extent_status *es)
+{
+	return (es->es_pblk & ES_TYPE_MASK) >> ES_SHIFT;
+}
+
+static inline int ext4_es_is_written(struct extent_status *es)
+{
+	return (ext4_es_type(es) & EXTENT_STATUS_WRITTEN) != 0;
+}
+
+static inline int ext4_es_is_unwritten(struct extent_status *es)
+{
+	return (ext4_es_type(es) & EXTENT_STATUS_UNWRITTEN) != 0;
+}
+
+static inline int ext4_es_is_delayed(struct extent_status *es)
+{
+	return (ext4_es_type(es) & EXTENT_STATUS_DELAYED) != 0;
+}
+
+static inline int ext4_es_is_hole(struct extent_status *es)
+{
+	return (ext4_es_type(es) & EXTENT_STATUS_HOLE) != 0;
+}
+
+static inline int ext4_es_is_mapped(struct extent_status *es)
+{
+	return (ext4_es_is_written(es) || ext4_es_is_unwritten(es));
+}
+
+static inline int ext4_es_is_delonly(struct extent_status *es)
+{
+	return (ext4_es_is_delayed(es) && !ext4_es_is_unwritten(es));
+}
+
+static inline void ext4_es_set_referenced(struct extent_status *es)
+{
+	es->es_pblk |= ((ext4_fsblk_t)EXTENT_STATUS_REFERENCED) << ES_SHIFT;
+}
+
+static inline void ext4_es_clear_referenced(struct extent_status *es)
+{
+	es->es_pblk &= ~(((ext4_fsblk_t)EXTENT_STATUS_REFERENCED) << ES_SHIFT);
+}
+
+static inline int ext4_es_is_referenced(struct extent_status *es)
+{
+	return (ext4_es_status(es) & EXTENT_STATUS_REFERENCED) != 0;
+}
+
+static inline ext4_fsblk_t ext4_es_pblock(struct extent_status *es)
+{
+	return es->es_pblk & ~ES_MASK;
+}
+
+static inline ext4_fsblk_t ext4_es_show_pblock(struct extent_status *es)
+{
+	ext4_fsblk_t pblock = ext4_es_pblock(es);
+	return pblock == ~ES_MASK ? 0 : pblock;
+}
+
+static inline void ext4_es_store_pblock(struct extent_status *es,
+					ext4_fsblk_t pb)
+{
+	ext4_fsblk_t block;
+
+	block = (pb & ~ES_MASK) | (es->es_pblk & ES_MASK);
+	es->es_pblk = block;
+}
+
+static inline void ext4_es_store_status(struct extent_status *es,
+					unsigned int status)
+{
+	es->es_pblk = (((ext4_fsblk_t)status << ES_SHIFT) & ES_MASK) |
+		      (es->es_pblk & ~ES_MASK);
+}
+
+static inline void ext4_es_store_pblock_status(struct extent_status *es,
+					       ext4_fsblk_t pb,
+					       unsigned int status)
+{
+	es->es_pblk = (((ext4_fsblk_t)status << ES_SHIFT) & ES_MASK) |
+		      (pb & ~ES_MASK);
+}
+
+extern int ext4_es_register_shrinker(struct ext4_sb_info *sbi);
+extern void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi);
+
+extern int ext4_seq_es_shrinker_info_show(struct seq_file *seq, void *v);
+
+extern int __init ext4_init_pending(void);
+extern void ext4_exit_pending(void);
+extern void ext4_init_pending_tree(struct ext4_pending_tree *tree);
+extern void ext4_remove_pending(struct inode *inode, ext4_lblk_t lblk);
+extern bool ext4_is_pending(struct inode *inode, ext4_lblk_t lblk);
+extern int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
+					bool allocated);
+extern unsigned int ext4_es_delayed_clu(struct inode *inode, ext4_lblk_t lblk,
+					ext4_lblk_t len);
+extern void ext4_clear_inode_es(struct inode *inode);
+
+#endif /* _EXT4_EXTENTS_STATUS_H */
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
new file mode 100644
index 000000000..be768ef1f
--- /dev/null
+++ b/fs/ext4/fast_commit.c
@@ -0,0 +1,2202 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * fs/ext4/fast_commit.c
+ *
+ * Written by Harshad Shirwadkar <harshadshirwadkar@gmail.com>
+ *
+ * Ext4 fast commits routines.
+ */
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "ext4_extents.h"
+#include "mballoc.h"
+
+/*
+ * Ext4 Fast Commits
+ * -----------------
+ *
+ * Ext4 fast commits implement fine grained journalling for Ext4.
+ *
+ * Fast commits are organized as a log of tag-length-value (TLV) structs. (See
+ * struct ext4_fc_tl). Each TLV contains some delta that is replayed TLV by
+ * TLV during the recovery phase. For the scenarios for which we currently
+ * don't have replay code, fast commit falls back to full commits.
+ * Fast commits record delta in one of the following three categories.
+ *
+ * (A) Directory entry updates:
+ *
+ * - EXT4_FC_TAG_UNLINK		- records directory entry unlink
+ * - EXT4_FC_TAG_LINK		- records directory entry link
+ * - EXT4_FC_TAG_CREAT		- records inode and directory entry creation
+ *
+ * (B) File specific data range updates:
+ *
+ * - EXT4_FC_TAG_ADD_RANGE	- records addition of new blocks to an inode
+ * - EXT4_FC_TAG_DEL_RANGE	- records deletion of blocks from an inode
+ *
+ * (C) Inode metadata (mtime / ctime etc):
+ *
+ * - EXT4_FC_TAG_INODE		- record the inode that should be replayed
+ *				  during recovery. Note that iblocks field is
+ *				  not replayed and instead derived during
+ *				  replay.
+ * Commit Operation
+ * ----------------
+ * With fast commits, we maintain all the directory entry operations in the
+ * order in which they are issued in an in-memory queue. This queue is flushed
+ * to disk during the commit operation. We also maintain a list of inodes
+ * that need to be committed during a fast commit in another in memory queue of
+ * inodes. During the commit operation, we commit in the following order:
+ *
+ * [1] Lock inodes for any further data updates by setting COMMITTING state
+ * [2] Submit data buffers of all the inodes
+ * [3] Wait for [2] to complete
+ * [4] Commit all the directory entry updates in the fast commit space
+ * [5] Commit all the changed inode structures
+ * [6] Write tail tag (this tag ensures the atomicity, please read the following
+ *     section for more details).
+ * [7] Wait for [4], [5] and [6] to complete.
+ *
+ * All the inode updates must call ext4_fc_start_update() before starting an
+ * update. If such an ongoing update is present, fast commit waits for it to
+ * complete. The completion of such an update is marked by
+ * ext4_fc_stop_update().
+ *
+ * Fast Commit Ineligibility
+ * -------------------------
+ * Not all operations are supported by fast commits today (e.g extended
+ * attributes). Fast commit ineligibility is marked by calling one of the
+ * two following functions:
+ *
+ * - ext4_fc_mark_ineligible(): This makes next fast commit operation to fall
+ *   back to full commit. This is useful in case of transient errors.
+ *
+ * - ext4_fc_start_ineligible() and ext4_fc_stop_ineligible() - This makes all
+ *   the fast commits happening between ext4_fc_start_ineligible() and
+ *   ext4_fc_stop_ineligible() and one fast commit after the call to
+ *   ext4_fc_stop_ineligible() to fall back to full commits. It is important to
+ *   make one more fast commit to fall back to full commit after stop call so
+ *   that it guaranteed that the fast commit ineligible operation contained
+ *   within ext4_fc_start_ineligible() and ext4_fc_stop_ineligible() is
+ *   followed by at least 1 full commit.
+ *
+ * Atomicity of commits
+ * --------------------
+ * In order to guarantee atomicity during the commit operation, fast commit
+ * uses "EXT4_FC_TAG_TAIL" tag that marks a fast commit as complete. Tail
+ * tag contains CRC of the contents and TID of the transaction after which
+ * this fast commit should be applied. Recovery code replays fast commit
+ * logs only if there's at least 1 valid tail present. For every fast commit
+ * operation, there is 1 tail. This means, we may end up with multiple tails
+ * in the fast commit space. Here's an example:
+ *
+ * - Create a new file A and remove existing file B
+ * - fsync()
+ * - Append contents to file A
+ * - Truncate file A
+ * - fsync()
+ *
+ * The fast commit space at the end of above operations would look like this:
+ *      [HEAD] [CREAT A] [UNLINK B] [TAIL] [ADD_RANGE A] [DEL_RANGE A] [TAIL]
+ *             |<---  Fast Commit 1   --->|<---      Fast Commit 2     ---->|
+ *
+ * Replay code should thus check for all the valid tails in the FC area.
+ *
+ * TODOs
+ * -----
+ * 1) Make fast commit atomic updates more fine grained. Today, a fast commit
+ *    eligible update must be protected within ext4_fc_start_update() and
+ *    ext4_fc_stop_update(). These routines are called at much higher
+ *    routines. This can be made more fine grained by combining with
+ *    ext4_journal_start().
+ *
+ * 2) Same above for ext4_fc_start_ineligible() and ext4_fc_stop_ineligible()
+ *
+ * 3) Handle more ineligible cases.
+ */
+
+#include <trace/events/ext4.h>
+static struct kmem_cache *ext4_fc_dentry_cachep;
+
+static void ext4_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
+{
+	BUFFER_TRACE(bh, "");
+	if (uptodate) {
+		ext4_debug("%s: Block %lld up-to-date",
+			   __func__, bh->b_blocknr);
+		set_buffer_uptodate(bh);
+	} else {
+		ext4_debug("%s: Block %lld not up-to-date",
+			   __func__, bh->b_blocknr);
+		clear_buffer_uptodate(bh);
+	}
+
+	unlock_buffer(bh);
+}
+
+static inline void ext4_fc_reset_inode(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	ei->i_fc_lblk_start = 0;
+	ei->i_fc_lblk_len = 0;
+}
+
+void ext4_fc_init_inode(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	ext4_fc_reset_inode(inode);
+	ext4_clear_inode_state(inode, EXT4_STATE_FC_COMMITTING);
+	INIT_LIST_HEAD(&ei->i_fc_list);
+	init_waitqueue_head(&ei->i_fc_wait);
+	atomic_set(&ei->i_fc_updates, 0);
+}
+
+/* This function must be called with sbi->s_fc_lock held. */
+static void ext4_fc_wait_committing_inode(struct inode *inode)
+__releases(&EXT4_SB(inode->i_sb)->s_fc_lock)
+{
+	wait_queue_head_t *wq;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+#if (BITS_PER_LONG < 64)
+	DEFINE_WAIT_BIT(wait, &ei->i_state_flags,
+			EXT4_STATE_FC_COMMITTING);
+	wq = bit_waitqueue(&ei->i_state_flags,
+				EXT4_STATE_FC_COMMITTING);
+#else
+	DEFINE_WAIT_BIT(wait, &ei->i_flags,
+			EXT4_STATE_FC_COMMITTING);
+	wq = bit_waitqueue(&ei->i_flags,
+				EXT4_STATE_FC_COMMITTING);
+#endif
+	lockdep_assert_held(&EXT4_SB(inode->i_sb)->s_fc_lock);
+	prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
+	spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+	schedule();
+	finish_wait(wq, &wait.wq_entry);
+}
+
+/*
+ * Inform Ext4's fast about start of an inode update
+ *
+ * This function is called by the high level call VFS callbacks before
+ * performing any inode update. This function blocks if there's an ongoing
+ * fast commit on the inode in question.
+ */
+void ext4_fc_start_update(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+restart:
+	spin_lock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+	if (list_empty(&ei->i_fc_list))
+		goto out;
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
+		ext4_fc_wait_committing_inode(inode);
+		goto restart;
+	}
+out:
+	atomic_inc(&ei->i_fc_updates);
+	spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+}
+
+/*
+ * Stop inode update and wake up waiting fast commits if any.
+ */
+void ext4_fc_stop_update(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	if (atomic_dec_and_test(&ei->i_fc_updates))
+		wake_up_all(&ei->i_fc_wait);
+}
+
+/*
+ * Remove inode from fast commit list. If the inode is being committed
+ * we wait until inode commit is done.
+ */
+void ext4_fc_del(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+restart:
+	spin_lock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+	if (list_empty(&ei->i_fc_list)) {
+		spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+		return;
+	}
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
+		ext4_fc_wait_committing_inode(inode);
+		goto restart;
+	}
+	list_del_init(&ei->i_fc_list);
+	spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+}
+
+/*
+ * Mark file system as fast commit ineligible. This means that next commit
+ * operation would result in a full jbd2 commit.
+ */
+void ext4_fc_mark_ineligible(struct super_block *sb, int reason)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	ext4_set_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
+	WARN_ON(reason >= EXT4_FC_REASON_MAX);
+	sbi->s_fc_stats.fc_ineligible_reason_count[reason]++;
+}
+
+/*
+ * Start a fast commit ineligible update. Any commits that happen while
+ * such an operation is in progress fall back to full commits.
+ */
+void ext4_fc_start_ineligible(struct super_block *sb, int reason)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	WARN_ON(reason >= EXT4_FC_REASON_MAX);
+	sbi->s_fc_stats.fc_ineligible_reason_count[reason]++;
+	atomic_inc(&sbi->s_fc_ineligible_updates);
+}
+
+/*
+ * Stop a fast commit ineligible update. We set EXT4_MF_FC_INELIGIBLE flag here
+ * to ensure that after stopping the ineligible update, at least one full
+ * commit takes place.
+ */
+void ext4_fc_stop_ineligible(struct super_block *sb)
+{
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	ext4_set_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
+	atomic_dec(&EXT4_SB(sb)->s_fc_ineligible_updates);
+}
+
+static inline int ext4_fc_is_ineligible(struct super_block *sb)
+{
+	return (ext4_test_mount_flag(sb, EXT4_MF_FC_INELIGIBLE) ||
+		atomic_read(&EXT4_SB(sb)->s_fc_ineligible_updates));
+}
+
+/*
+ * Generic fast commit tracking function. If this is the first time this we are
+ * called after a full commit, we initialize fast commit fields and then call
+ * __fc_track_fn() with update = 0. If we have already been called after a full
+ * commit, we pass update = 1. Based on that, the track function can determine
+ * if it needs to track a field for the first time or if it needs to just
+ * update the previously tracked value.
+ *
+ * If enqueue is set, this function enqueues the inode in fast commit list.
+ */
+static int ext4_fc_track_template(
+	handle_t *handle, struct inode *inode,
+	int (*__fc_track_fn)(struct inode *, void *, bool),
+	void *args, int enqueue)
+{
+	bool update = false;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	tid_t tid = 0;
+	int ret;
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (sbi->s_mount_state & EXT4_FC_REPLAY))
+		return -EOPNOTSUPP;
+
+	if (ext4_fc_is_ineligible(inode->i_sb))
+		return -EINVAL;
+
+	tid = handle->h_transaction->t_tid;
+	mutex_lock(&ei->i_fc_lock);
+	if (tid == ei->i_sync_tid) {
+		update = true;
+	} else {
+		ext4_fc_reset_inode(inode);
+		ei->i_sync_tid = tid;
+	}
+	ret = __fc_track_fn(inode, args, update);
+	mutex_unlock(&ei->i_fc_lock);
+
+	if (!enqueue)
+		return ret;
+
+	spin_lock(&sbi->s_fc_lock);
+	if (list_empty(&EXT4_I(inode)->i_fc_list))
+		list_add_tail(&EXT4_I(inode)->i_fc_list,
+				(ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_COMMITTING)) ?
+				&sbi->s_fc_q[FC_Q_STAGING] :
+				&sbi->s_fc_q[FC_Q_MAIN]);
+	spin_unlock(&sbi->s_fc_lock);
+
+	return ret;
+}
+
+struct __track_dentry_update_args {
+	struct dentry *dentry;
+	int op;
+};
+
+/* __track_fn for directory entry updates. Called with ei->i_fc_lock. */
+static int __track_dentry_update(struct inode *inode, void *arg, bool update)
+{
+	struct ext4_fc_dentry_update *node;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct __track_dentry_update_args *dentry_update =
+		(struct __track_dentry_update_args *)arg;
+	struct dentry *dentry = dentry_update->dentry;
+	struct inode *dir = dentry->d_parent->d_inode;
+	struct super_block *sb = inode->i_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	mutex_unlock(&ei->i_fc_lock);
+
+	if (IS_ENCRYPTED(dir)) {
+		ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_ENCRYPTED_FILENAME);
+		mutex_lock(&ei->i_fc_lock);
+		return -EOPNOTSUPP;
+	}
+
+	node = kmem_cache_alloc(ext4_fc_dentry_cachep, GFP_NOFS);
+	if (!node) {
+		ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM);
+		mutex_lock(&ei->i_fc_lock);
+		return -ENOMEM;
+	}
+
+	node->fcd_op = dentry_update->op;
+	node->fcd_parent = dir->i_ino;
+	node->fcd_ino = inode->i_ino;
+	if (dentry->d_name.len > DNAME_INLINE_LEN) {
+		node->fcd_name.name = kmalloc(dentry->d_name.len, GFP_NOFS);
+		if (!node->fcd_name.name) {
+			kmem_cache_free(ext4_fc_dentry_cachep, node);
+			ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM);
+			mutex_lock(&ei->i_fc_lock);
+			return -ENOMEM;
+		}
+		memcpy((u8 *)node->fcd_name.name, dentry->d_name.name,
+			dentry->d_name.len);
+	} else {
+		memcpy(node->fcd_iname, dentry->d_name.name,
+			dentry->d_name.len);
+		node->fcd_name.name = node->fcd_iname;
+	}
+	node->fcd_name.len = dentry->d_name.len;
+
+	spin_lock(&sbi->s_fc_lock);
+	if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_COMMITTING))
+		list_add_tail(&node->fcd_list,
+				&sbi->s_fc_dentry_q[FC_Q_STAGING]);
+	else
+		list_add_tail(&node->fcd_list, &sbi->s_fc_dentry_q[FC_Q_MAIN]);
+	spin_unlock(&sbi->s_fc_lock);
+	mutex_lock(&ei->i_fc_lock);
+
+	return 0;
+}
+
+void __ext4_fc_track_unlink(handle_t *handle,
+		struct inode *inode, struct dentry *dentry)
+{
+	struct __track_dentry_update_args args;
+	int ret;
+
+	args.dentry = dentry;
+	args.op = EXT4_FC_TAG_UNLINK;
+
+	ret = ext4_fc_track_template(handle, inode, __track_dentry_update,
+					(void *)&args, 0);
+	trace_ext4_fc_track_unlink(inode, dentry, ret);
+}
+
+void ext4_fc_track_unlink(handle_t *handle, struct dentry *dentry)
+{
+	__ext4_fc_track_unlink(handle, d_inode(dentry), dentry);
+}
+
+void __ext4_fc_track_link(handle_t *handle,
+	struct inode *inode, struct dentry *dentry)
+{
+	struct __track_dentry_update_args args;
+	int ret;
+
+	args.dentry = dentry;
+	args.op = EXT4_FC_TAG_LINK;
+
+	ret = ext4_fc_track_template(handle, inode, __track_dentry_update,
+					(void *)&args, 0);
+	trace_ext4_fc_track_link(inode, dentry, ret);
+}
+
+void ext4_fc_track_link(handle_t *handle, struct dentry *dentry)
+{
+	__ext4_fc_track_link(handle, d_inode(dentry), dentry);
+}
+
+void __ext4_fc_track_create(handle_t *handle, struct inode *inode,
+			  struct dentry *dentry)
+{
+	struct __track_dentry_update_args args;
+	int ret;
+
+	args.dentry = dentry;
+	args.op = EXT4_FC_TAG_CREAT;
+
+	ret = ext4_fc_track_template(handle, inode, __track_dentry_update,
+					(void *)&args, 0);
+	trace_ext4_fc_track_create(inode, dentry, ret);
+}
+
+void ext4_fc_track_create(handle_t *handle, struct dentry *dentry)
+{
+	__ext4_fc_track_create(handle, d_inode(dentry), dentry);
+}
+
+/* __track_fn for inode tracking */
+static int __track_inode(struct inode *inode, void *arg, bool update)
+{
+	if (update)
+		return -EEXIST;
+
+	EXT4_I(inode)->i_fc_lblk_len = 0;
+
+	return 0;
+}
+
+void ext4_fc_track_inode(handle_t *handle, struct inode *inode)
+{
+	int ret;
+
+	if (S_ISDIR(inode->i_mode))
+		return;
+
+	if (ext4_should_journal_data(inode)) {
+		ext4_fc_mark_ineligible(inode->i_sb,
+					EXT4_FC_REASON_INODE_JOURNAL_DATA);
+		return;
+	}
+
+	ret = ext4_fc_track_template(handle, inode, __track_inode, NULL, 1);
+	trace_ext4_fc_track_inode(inode, ret);
+}
+
+struct __track_range_args {
+	ext4_lblk_t start, end;
+};
+
+/* __track_fn for tracking data updates */
+static int __track_range(struct inode *inode, void *arg, bool update)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	ext4_lblk_t oldstart;
+	struct __track_range_args *__arg =
+		(struct __track_range_args *)arg;
+
+	if (inode->i_ino < EXT4_FIRST_INO(inode->i_sb)) {
+		ext4_debug("Special inode %ld being modified\n", inode->i_ino);
+		return -ECANCELED;
+	}
+
+	oldstart = ei->i_fc_lblk_start;
+
+	if (update && ei->i_fc_lblk_len > 0) {
+		ei->i_fc_lblk_start = min(ei->i_fc_lblk_start, __arg->start);
+		ei->i_fc_lblk_len =
+			max(oldstart + ei->i_fc_lblk_len - 1, __arg->end) -
+				ei->i_fc_lblk_start + 1;
+	} else {
+		ei->i_fc_lblk_start = __arg->start;
+		ei->i_fc_lblk_len = __arg->end - __arg->start + 1;
+	}
+
+	return 0;
+}
+
+void ext4_fc_track_range(handle_t *handle, struct inode *inode, ext4_lblk_t start,
+			 ext4_lblk_t end)
+{
+	struct __track_range_args args;
+	int ret;
+
+	if (S_ISDIR(inode->i_mode))
+		return;
+
+	args.start = start;
+	args.end = end;
+
+	ret = ext4_fc_track_template(handle, inode,  __track_range, &args, 1);
+
+	trace_ext4_fc_track_range(inode, start, end, ret);
+}
+
+static void ext4_fc_submit_bh(struct super_block *sb)
+{
+	int write_flags = REQ_SYNC;
+	struct buffer_head *bh = EXT4_SB(sb)->s_fc_bh;
+
+	/* TODO: REQ_FUA | REQ_PREFLUSH is unnecessarily expensive. */
+	if (test_opt(sb, BARRIER))
+		write_flags |= REQ_FUA | REQ_PREFLUSH;
+	lock_buffer(bh);
+	set_buffer_dirty(bh);
+	set_buffer_uptodate(bh);
+	bh->b_end_io = ext4_end_buffer_io_sync;
+	submit_bh(REQ_OP_WRITE, write_flags, bh);
+	EXT4_SB(sb)->s_fc_bh = NULL;
+}
+
+/* Ext4 commit path routines */
+
+/* memzero and update CRC */
+static void *ext4_fc_memzero(struct super_block *sb, void *dst, int len,
+				u32 *crc)
+{
+	void *ret;
+
+	ret = memset(dst, 0, len);
+	if (crc)
+		*crc = ext4_chksum(EXT4_SB(sb), *crc, dst, len);
+	return ret;
+}
+
+/*
+ * Allocate len bytes on a fast commit buffer.
+ *
+ * During the commit time this function is used to manage fast commit
+ * block space. We don't split a fast commit log onto different
+ * blocks. So this function makes sure that if there's not enough space
+ * on the current block, the remaining space in the current block is
+ * marked as unused by adding EXT4_FC_TAG_PAD tag. In that case,
+ * new block is from jbd2 and CRC is updated to reflect the padding
+ * we added.
+ */
+static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc)
+{
+	struct ext4_fc_tl *tl;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct buffer_head *bh;
+	int bsize = sbi->s_journal->j_blocksize;
+	int ret, off = sbi->s_fc_bytes % bsize;
+	int pad_len;
+
+	/*
+	 * After allocating len, we should have space at least for a 0 byte
+	 * padding.
+	 */
+	if (len + sizeof(struct ext4_fc_tl) > bsize)
+		return NULL;
+
+	if (bsize - off - 1 > len + sizeof(struct ext4_fc_tl)) {
+		/*
+		 * Only allocate from current buffer if we have enough space for
+		 * this request AND we have space to add a zero byte padding.
+		 */
+		if (!sbi->s_fc_bh) {
+			ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh);
+			if (ret)
+				return NULL;
+			sbi->s_fc_bh = bh;
+		}
+		sbi->s_fc_bytes += len;
+		return sbi->s_fc_bh->b_data + off;
+	}
+	/* Need to add PAD tag */
+	tl = (struct ext4_fc_tl *)(sbi->s_fc_bh->b_data + off);
+	tl->fc_tag = cpu_to_le16(EXT4_FC_TAG_PAD);
+	pad_len = bsize - off - 1 - sizeof(struct ext4_fc_tl);
+	tl->fc_len = cpu_to_le16(pad_len);
+	if (crc)
+		*crc = ext4_chksum(sbi, *crc, tl, sizeof(*tl));
+	if (pad_len > 0)
+		ext4_fc_memzero(sb, tl + 1, pad_len, crc);
+	/* Don't leak uninitialized memory in the unused last byte. */
+	*((u8 *)(tl + 1) + pad_len) = 0;
+
+	ext4_fc_submit_bh(sb);
+
+	ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh);
+	if (ret)
+		return NULL;
+	sbi->s_fc_bh = bh;
+	sbi->s_fc_bytes = (sbi->s_fc_bytes / bsize + 1) * bsize + len;
+	return sbi->s_fc_bh->b_data;
+}
+
+/* memcpy to fc reserved space and update CRC */
+static void *ext4_fc_memcpy(struct super_block *sb, void *dst, const void *src,
+				int len, u32 *crc)
+{
+	if (crc)
+		*crc = ext4_chksum(EXT4_SB(sb), *crc, src, len);
+	return memcpy(dst, src, len);
+}
+
+/*
+ * Complete a fast commit by writing tail tag.
+ *
+ * Writing tail tag marks the end of a fast commit. In order to guarantee
+ * atomicity, after writing tail tag, even if there's space remaining
+ * in the block, next commit shouldn't use it. That's why tail tag
+ * has the length as that of the remaining space on the block.
+ */
+static int ext4_fc_write_tail(struct super_block *sb, u32 crc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_tl tl;
+	struct ext4_fc_tail tail;
+	int off, bsize = sbi->s_journal->j_blocksize;
+	u8 *dst;
+
+	/*
+	 * ext4_fc_reserve_space takes care of allocating an extra block if
+	 * there's no enough space on this block for accommodating this tail.
+	 */
+	dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(tail), &crc);
+	if (!dst)
+		return -ENOSPC;
+
+	off = sbi->s_fc_bytes % bsize;
+
+	tl.fc_tag = cpu_to_le16(EXT4_FC_TAG_TAIL);
+	tl.fc_len = cpu_to_le16(bsize - off - 1 + sizeof(struct ext4_fc_tail));
+	sbi->s_fc_bytes = round_up(sbi->s_fc_bytes, bsize);
+
+	ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), &crc);
+	dst += sizeof(tl);
+	tail.fc_tid = cpu_to_le32(sbi->s_journal->j_running_transaction->t_tid);
+	ext4_fc_memcpy(sb, dst, &tail.fc_tid, sizeof(tail.fc_tid), &crc);
+	dst += sizeof(tail.fc_tid);
+	tail.fc_crc = cpu_to_le32(crc);
+	ext4_fc_memcpy(sb, dst, &tail.fc_crc, sizeof(tail.fc_crc), NULL);
+	dst += sizeof(tail.fc_crc);
+	memset(dst, 0, bsize - off); /* Don't leak uninitialized memory. */
+
+	ext4_fc_submit_bh(sb);
+
+	return 0;
+}
+
+/*
+ * Adds tag, length, value and updates CRC. Returns true if tlv was added.
+ * Returns false if there's not enough space.
+ */
+static bool ext4_fc_add_tlv(struct super_block *sb, u16 tag, u16 len, u8 *val,
+			   u32 *crc)
+{
+	struct ext4_fc_tl tl;
+	u8 *dst;
+
+	dst = ext4_fc_reserve_space(sb, sizeof(tl) + len, crc);
+	if (!dst)
+		return false;
+
+	tl.fc_tag = cpu_to_le16(tag);
+	tl.fc_len = cpu_to_le16(len);
+
+	ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc);
+	ext4_fc_memcpy(sb, dst + sizeof(tl), val, len, crc);
+
+	return true;
+}
+
+/* Same as above, but adds dentry tlv. */
+static  bool ext4_fc_add_dentry_tlv(struct super_block *sb, u16 tag,
+					int parent_ino, int ino, int dlen,
+					const unsigned char *dname,
+					u32 *crc)
+{
+	struct ext4_fc_dentry_info fcd;
+	struct ext4_fc_tl tl;
+	u8 *dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(fcd) + dlen,
+					crc);
+
+	if (!dst)
+		return false;
+
+	fcd.fc_parent_ino = cpu_to_le32(parent_ino);
+	fcd.fc_ino = cpu_to_le32(ino);
+	tl.fc_tag = cpu_to_le16(tag);
+	tl.fc_len = cpu_to_le16(sizeof(fcd) + dlen);
+	ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc);
+	dst += sizeof(tl);
+	ext4_fc_memcpy(sb, dst, &fcd, sizeof(fcd), crc);
+	dst += sizeof(fcd);
+	ext4_fc_memcpy(sb, dst, dname, dlen, crc);
+	dst += dlen;
+
+	return true;
+}
+
+/*
+ * Writes inode in the fast commit space under TLV with tag @tag.
+ * Returns 0 on success, error on failure.
+ */
+static int ext4_fc_write_inode(struct inode *inode, u32 *crc)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	int inode_len = EXT4_GOOD_OLD_INODE_SIZE;
+	int ret;
+	struct ext4_iloc iloc;
+	struct ext4_fc_inode fc_inode;
+	struct ext4_fc_tl tl;
+	u8 *dst;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE)
+		inode_len += ei->i_extra_isize;
+
+	fc_inode.fc_ino = cpu_to_le32(inode->i_ino);
+	tl.fc_tag = cpu_to_le16(EXT4_FC_TAG_INODE);
+	tl.fc_len = cpu_to_le16(inode_len + sizeof(fc_inode.fc_ino));
+
+	ret = -ECANCELED;
+	dst = ext4_fc_reserve_space(inode->i_sb,
+			sizeof(tl) + inode_len + sizeof(fc_inode.fc_ino), crc);
+	if (!dst)
+		goto err;
+
+	if (!ext4_fc_memcpy(inode->i_sb, dst, &tl, sizeof(tl), crc))
+		goto err;
+	dst += sizeof(tl);
+	if (!ext4_fc_memcpy(inode->i_sb, dst, &fc_inode, sizeof(fc_inode), crc))
+		goto err;
+	dst += sizeof(fc_inode);
+	if (!ext4_fc_memcpy(inode->i_sb, dst, (u8 *)ext4_raw_inode(&iloc),
+					inode_len, crc))
+		goto err;
+	ret = 0;
+err:
+	brelse(iloc.bh);
+	return ret;
+}
+
+/*
+ * Writes updated data ranges for the inode in question. Updates CRC.
+ * Returns 0 on success, error otherwise.
+ */
+static int ext4_fc_write_inode_data(struct inode *inode, u32 *crc)
+{
+	ext4_lblk_t old_blk_size, cur_lblk_off, new_blk_size;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_map_blocks map;
+	struct ext4_fc_add_range fc_ext;
+	struct ext4_fc_del_range lrange;
+	struct ext4_extent *ex;
+	int ret;
+
+	mutex_lock(&ei->i_fc_lock);
+	if (ei->i_fc_lblk_len == 0) {
+		mutex_unlock(&ei->i_fc_lock);
+		return 0;
+	}
+	old_blk_size = ei->i_fc_lblk_start;
+	new_blk_size = ei->i_fc_lblk_start + ei->i_fc_lblk_len - 1;
+	ei->i_fc_lblk_len = 0;
+	mutex_unlock(&ei->i_fc_lock);
+
+	cur_lblk_off = old_blk_size;
+	jbd_debug(1, "%s: will try writing %d to %d for inode %ld\n",
+		  __func__, cur_lblk_off, new_blk_size, inode->i_ino);
+
+	while (cur_lblk_off <= new_blk_size) {
+		map.m_lblk = cur_lblk_off;
+		map.m_len = new_blk_size - cur_lblk_off + 1;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0)
+			return -ECANCELED;
+
+		if (map.m_len == 0) {
+			cur_lblk_off++;
+			continue;
+		}
+
+		if (ret == 0) {
+			lrange.fc_ino = cpu_to_le32(inode->i_ino);
+			lrange.fc_lblk = cpu_to_le32(map.m_lblk);
+			lrange.fc_len = cpu_to_le32(map.m_len);
+			if (!ext4_fc_add_tlv(inode->i_sb, EXT4_FC_TAG_DEL_RANGE,
+					    sizeof(lrange), (u8 *)&lrange, crc))
+				return -ENOSPC;
+		} else {
+			unsigned int max = (map.m_flags & EXT4_MAP_UNWRITTEN) ?
+				EXT_UNWRITTEN_MAX_LEN : EXT_INIT_MAX_LEN;
+
+			/* Limit the number of blocks in one extent */
+			map.m_len = min(max, map.m_len);
+
+			fc_ext.fc_ino = cpu_to_le32(inode->i_ino);
+			ex = (struct ext4_extent *)&fc_ext.fc_ex;
+			ex->ee_block = cpu_to_le32(map.m_lblk);
+			ex->ee_len = cpu_to_le16(map.m_len);
+			ext4_ext_store_pblock(ex, map.m_pblk);
+			if (map.m_flags & EXT4_MAP_UNWRITTEN)
+				ext4_ext_mark_unwritten(ex);
+			else
+				ext4_ext_mark_initialized(ex);
+			if (!ext4_fc_add_tlv(inode->i_sb, EXT4_FC_TAG_ADD_RANGE,
+					    sizeof(fc_ext), (u8 *)&fc_ext, crc))
+				return -ENOSPC;
+		}
+
+		cur_lblk_off += map.m_len;
+	}
+
+	return 0;
+}
+
+
+/* Submit data for all the fast commit inodes */
+static int ext4_fc_submit_inode_data_all(journal_t *journal)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *ei;
+	struct list_head *pos;
+	int ret = 0;
+
+	spin_lock(&sbi->s_fc_lock);
+	ext4_set_mount_flag(sb, EXT4_MF_FC_COMMITTING);
+	list_for_each(pos, &sbi->s_fc_q[FC_Q_MAIN]) {
+		ei = list_entry(pos, struct ext4_inode_info, i_fc_list);
+		ext4_set_inode_state(&ei->vfs_inode, EXT4_STATE_FC_COMMITTING);
+		while (atomic_read(&ei->i_fc_updates)) {
+			DEFINE_WAIT(wait);
+
+			prepare_to_wait(&ei->i_fc_wait, &wait,
+						TASK_UNINTERRUPTIBLE);
+			if (atomic_read(&ei->i_fc_updates)) {
+				spin_unlock(&sbi->s_fc_lock);
+				schedule();
+				spin_lock(&sbi->s_fc_lock);
+			}
+			finish_wait(&ei->i_fc_wait, &wait);
+		}
+		spin_unlock(&sbi->s_fc_lock);
+		ret = jbd2_submit_inode_data(ei->jinode);
+		if (ret)
+			return ret;
+		spin_lock(&sbi->s_fc_lock);
+	}
+	spin_unlock(&sbi->s_fc_lock);
+
+	return ret;
+}
+
+/* Wait for completion of data for all the fast commit inodes */
+static int ext4_fc_wait_inode_data_all(journal_t *journal)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *pos, *n;
+	int ret = 0;
+
+	spin_lock(&sbi->s_fc_lock);
+	list_for_each_entry_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
+		if (!ext4_test_inode_state(&pos->vfs_inode,
+					   EXT4_STATE_FC_COMMITTING))
+			continue;
+		spin_unlock(&sbi->s_fc_lock);
+
+		ret = jbd2_wait_inode_data(journal, pos->jinode);
+		if (ret)
+			return ret;
+		spin_lock(&sbi->s_fc_lock);
+	}
+	spin_unlock(&sbi->s_fc_lock);
+
+	return 0;
+}
+
+/* Commit all the directory entry updates */
+static int ext4_fc_commit_dentry_updates(journal_t *journal, u32 *crc)
+__acquires(&sbi->s_fc_lock)
+__releases(&sbi->s_fc_lock)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_dentry_update *fc_dentry;
+	struct inode *inode;
+	struct list_head *pos, *n, *fcd_pos, *fcd_n;
+	struct ext4_inode_info *ei;
+	int ret;
+
+	if (list_empty(&sbi->s_fc_dentry_q[FC_Q_MAIN]))
+		return 0;
+	list_for_each_safe(fcd_pos, fcd_n, &sbi->s_fc_dentry_q[FC_Q_MAIN]) {
+		fc_dentry = list_entry(fcd_pos, struct ext4_fc_dentry_update,
+					fcd_list);
+		if (fc_dentry->fcd_op != EXT4_FC_TAG_CREAT) {
+			spin_unlock(&sbi->s_fc_lock);
+			if (!ext4_fc_add_dentry_tlv(
+				sb, fc_dentry->fcd_op,
+				fc_dentry->fcd_parent, fc_dentry->fcd_ino,
+				fc_dentry->fcd_name.len,
+				fc_dentry->fcd_name.name, crc)) {
+				ret = -ENOSPC;
+				goto lock_and_exit;
+			}
+			spin_lock(&sbi->s_fc_lock);
+			continue;
+		}
+
+		inode = NULL;
+		list_for_each_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN]) {
+			ei = list_entry(pos, struct ext4_inode_info, i_fc_list);
+			if (ei->vfs_inode.i_ino == fc_dentry->fcd_ino) {
+				inode = &ei->vfs_inode;
+				break;
+			}
+		}
+		/*
+		 * If we don't find inode in our list, then it was deleted,
+		 * in which case, we don't need to record it's create tag.
+		 */
+		if (!inode)
+			continue;
+		spin_unlock(&sbi->s_fc_lock);
+
+		/*
+		 * We first write the inode and then the create dirent. This
+		 * allows the recovery code to create an unnamed inode first
+		 * and then link it to a directory entry. This allows us
+		 * to use namei.c routines almost as is and simplifies
+		 * the recovery code.
+		 */
+		ret = ext4_fc_write_inode(inode, crc);
+		if (ret)
+			goto lock_and_exit;
+
+		ret = ext4_fc_write_inode_data(inode, crc);
+		if (ret)
+			goto lock_and_exit;
+
+		if (!ext4_fc_add_dentry_tlv(
+			sb, fc_dentry->fcd_op,
+			fc_dentry->fcd_parent, fc_dentry->fcd_ino,
+			fc_dentry->fcd_name.len,
+			fc_dentry->fcd_name.name, crc)) {
+			ret = -ENOSPC;
+			goto lock_and_exit;
+		}
+
+		spin_lock(&sbi->s_fc_lock);
+	}
+	return 0;
+lock_and_exit:
+	spin_lock(&sbi->s_fc_lock);
+	return ret;
+}
+
+static int ext4_fc_perform_commit(journal_t *journal)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *iter;
+	struct ext4_fc_head head;
+	struct list_head *pos;
+	struct inode *inode;
+	struct blk_plug plug;
+	int ret = 0;
+	u32 crc = 0;
+
+	ret = ext4_fc_submit_inode_data_all(journal);
+	if (ret)
+		return ret;
+
+	ret = ext4_fc_wait_inode_data_all(journal);
+	if (ret)
+		return ret;
+
+	/*
+	 * If file system device is different from journal device, issue a cache
+	 * flush before we start writing fast commit blocks.
+	 */
+	if (journal->j_fs_dev != journal->j_dev)
+		blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS);
+
+	blk_start_plug(&plug);
+	if (sbi->s_fc_bytes == 0) {
+		/*
+		 * Add a head tag only if this is the first fast commit
+		 * in this TID.
+		 */
+		head.fc_features = cpu_to_le32(EXT4_FC_SUPPORTED_FEATURES);
+		head.fc_tid = cpu_to_le32(
+			sbi->s_journal->j_running_transaction->t_tid);
+		if (!ext4_fc_add_tlv(sb, EXT4_FC_TAG_HEAD, sizeof(head),
+			(u8 *)&head, &crc)) {
+			ret = -ENOSPC;
+			goto out;
+		}
+	}
+
+	spin_lock(&sbi->s_fc_lock);
+	ret = ext4_fc_commit_dentry_updates(journal, &crc);
+	if (ret) {
+		spin_unlock(&sbi->s_fc_lock);
+		goto out;
+	}
+
+	list_for_each(pos, &sbi->s_fc_q[FC_Q_MAIN]) {
+		iter = list_entry(pos, struct ext4_inode_info, i_fc_list);
+		inode = &iter->vfs_inode;
+		if (!ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING))
+			continue;
+
+		spin_unlock(&sbi->s_fc_lock);
+		ret = ext4_fc_write_inode_data(inode, &crc);
+		if (ret)
+			goto out;
+		ret = ext4_fc_write_inode(inode, &crc);
+		if (ret)
+			goto out;
+		spin_lock(&sbi->s_fc_lock);
+	}
+	spin_unlock(&sbi->s_fc_lock);
+
+	ret = ext4_fc_write_tail(sb, crc);
+
+out:
+	blk_finish_plug(&plug);
+	return ret;
+}
+
+/*
+ * The main commit entry point. Performs a fast commit for transaction
+ * commit_tid if needed. If it's not possible to perform a fast commit
+ * due to various reasons, we fall back to full commit. Returns 0
+ * on success, error otherwise.
+ */
+int ext4_fc_commit(journal_t *journal, tid_t commit_tid)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int nblks = 0, ret, bsize = journal->j_blocksize;
+	int subtid = atomic_read(&sbi->s_fc_subtid);
+	int reason = EXT4_FC_REASON_OK, fc_bufs_before = 0;
+	ktime_t start_time, commit_time;
+
+	trace_ext4_fc_commit_start(sb);
+
+	start_time = ktime_get();
+
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+		(ext4_fc_is_ineligible(sb))) {
+		reason = EXT4_FC_REASON_INELIGIBLE;
+		goto out;
+	}
+
+restart_fc:
+	ret = jbd2_fc_begin_commit(journal, commit_tid);
+	if (ret == -EALREADY) {
+		/* There was an ongoing commit, check if we need to restart */
+		if (atomic_read(&sbi->s_fc_subtid) <= subtid &&
+			commit_tid > journal->j_commit_sequence)
+			goto restart_fc;
+		reason = EXT4_FC_REASON_ALREADY_COMMITTED;
+		goto out;
+	} else if (ret) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_FC_START_FAILED;
+		goto out;
+	}
+
+	fc_bufs_before = (sbi->s_fc_bytes + bsize - 1) / bsize;
+	ret = ext4_fc_perform_commit(journal);
+	if (ret < 0) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_FC_FAILED;
+		goto out;
+	}
+	nblks = (sbi->s_fc_bytes + bsize - 1) / bsize - fc_bufs_before;
+	ret = jbd2_fc_wait_bufs(journal, nblks);
+	if (ret < 0) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_FC_FAILED;
+		goto out;
+	}
+	atomic_inc(&sbi->s_fc_subtid);
+	jbd2_fc_end_commit(journal);
+out:
+	/* Has any ineligible update happened since we started? */
+	if (reason == EXT4_FC_REASON_OK && ext4_fc_is_ineligible(sb)) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_INELIGIBLE;
+	}
+
+	spin_lock(&sbi->s_fc_lock);
+	if (reason != EXT4_FC_REASON_OK &&
+		reason != EXT4_FC_REASON_ALREADY_COMMITTED) {
+		sbi->s_fc_stats.fc_ineligible_commits++;
+	} else {
+		sbi->s_fc_stats.fc_num_commits++;
+		sbi->s_fc_stats.fc_numblks += nblks;
+	}
+	spin_unlock(&sbi->s_fc_lock);
+	nblks = (reason == EXT4_FC_REASON_OK) ? nblks : 0;
+	trace_ext4_fc_commit_stop(sb, nblks, reason);
+	commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
+	/*
+	 * weight the commit time higher than the average time so we don't
+	 * react too strongly to vast changes in the commit time
+	 */
+	if (likely(sbi->s_fc_avg_commit_time))
+		sbi->s_fc_avg_commit_time = (commit_time +
+				sbi->s_fc_avg_commit_time * 3) / 4;
+	else
+		sbi->s_fc_avg_commit_time = commit_time;
+	jbd_debug(1,
+		"Fast commit ended with blks = %d, reason = %d, subtid - %d",
+		nblks, reason, subtid);
+	if (reason == EXT4_FC_REASON_FC_FAILED)
+		return jbd2_fc_end_commit_fallback(journal);
+	if (reason == EXT4_FC_REASON_FC_START_FAILED ||
+		reason == EXT4_FC_REASON_INELIGIBLE)
+		return jbd2_complete_transaction(journal, commit_tid);
+	return 0;
+}
+
+/*
+ * Fast commit cleanup routine. This is called after every fast commit and
+ * full commit. full is true if we are called after a full commit.
+ */
+static void ext4_fc_cleanup(journal_t *journal, int full)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *iter;
+	struct ext4_fc_dentry_update *fc_dentry;
+	struct list_head *pos, *n;
+
+	if (full && sbi->s_fc_bh)
+		sbi->s_fc_bh = NULL;
+
+	jbd2_fc_release_bufs(journal);
+
+	spin_lock(&sbi->s_fc_lock);
+	list_for_each_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN]) {
+		iter = list_entry(pos, struct ext4_inode_info, i_fc_list);
+		list_del_init(&iter->i_fc_list);
+		ext4_clear_inode_state(&iter->vfs_inode,
+				       EXT4_STATE_FC_COMMITTING);
+		ext4_fc_reset_inode(&iter->vfs_inode);
+		/* Make sure EXT4_STATE_FC_COMMITTING bit is clear */
+		smp_mb();
+#if (BITS_PER_LONG < 64)
+		wake_up_bit(&iter->i_state_flags, EXT4_STATE_FC_COMMITTING);
+#else
+		wake_up_bit(&iter->i_flags, EXT4_STATE_FC_COMMITTING);
+#endif
+	}
+
+	while (!list_empty(&sbi->s_fc_dentry_q[FC_Q_MAIN])) {
+		fc_dentry = list_first_entry(&sbi->s_fc_dentry_q[FC_Q_MAIN],
+					     struct ext4_fc_dentry_update,
+					     fcd_list);
+		list_del_init(&fc_dentry->fcd_list);
+		spin_unlock(&sbi->s_fc_lock);
+
+		if (fc_dentry->fcd_name.name &&
+			fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
+			kfree(fc_dentry->fcd_name.name);
+		kmem_cache_free(ext4_fc_dentry_cachep, fc_dentry);
+		spin_lock(&sbi->s_fc_lock);
+	}
+
+	list_splice_init(&sbi->s_fc_dentry_q[FC_Q_STAGING],
+				&sbi->s_fc_dentry_q[FC_Q_MAIN]);
+	list_splice_init(&sbi->s_fc_q[FC_Q_STAGING],
+				&sbi->s_fc_q[FC_Q_MAIN]);
+
+	ext4_clear_mount_flag(sb, EXT4_MF_FC_COMMITTING);
+	ext4_clear_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
+
+	if (full)
+		sbi->s_fc_bytes = 0;
+	spin_unlock(&sbi->s_fc_lock);
+	trace_ext4_fc_stats(sb);
+}
+
+/* Ext4 Replay Path Routines */
+
+/* Helper struct for dentry replay routines */
+struct dentry_info_args {
+	int parent_ino, dname_len, ino, inode_len;
+	char *dname;
+};
+
+static inline void tl_to_darg(struct dentry_info_args *darg,
+			      struct  ext4_fc_tl *tl, u8 *val)
+{
+	struct ext4_fc_dentry_info fcd;
+
+	memcpy(&fcd, val, sizeof(fcd));
+
+	darg->parent_ino = le32_to_cpu(fcd.fc_parent_ino);
+	darg->ino = le32_to_cpu(fcd.fc_ino);
+	darg->dname = val + offsetof(struct ext4_fc_dentry_info, fc_dname);
+	darg->dname_len = le16_to_cpu(tl->fc_len) -
+		sizeof(struct ext4_fc_dentry_info);
+}
+
+/* Unlink replay function */
+static int ext4_fc_replay_unlink(struct super_block *sb, struct ext4_fc_tl *tl,
+				 u8 *val)
+{
+	struct inode *inode, *old_parent;
+	struct qstr entry;
+	struct dentry_info_args darg;
+	int ret = 0;
+
+	tl_to_darg(&darg, tl, val);
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_UNLINK, darg.ino,
+			darg.parent_ino, darg.dname_len);
+
+	entry.name = darg.dname;
+	entry.len = darg.dname_len;
+	inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
+
+	if (IS_ERR(inode)) {
+		jbd_debug(1, "Inode %d not found", darg.ino);
+		return 0;
+	}
+
+	old_parent = ext4_iget(sb, darg.parent_ino,
+				EXT4_IGET_NORMAL);
+	if (IS_ERR(old_parent)) {
+		jbd_debug(1, "Dir with inode  %d not found", darg.parent_ino);
+		iput(inode);
+		return 0;
+	}
+
+	ret = __ext4_unlink(old_parent, &entry, inode, NULL);
+	/* -ENOENT ok coz it might not exist anymore. */
+	if (ret == -ENOENT)
+		ret = 0;
+	iput(old_parent);
+	iput(inode);
+	return ret;
+}
+
+static int ext4_fc_replay_link_internal(struct super_block *sb,
+				struct dentry_info_args *darg,
+				struct inode *inode)
+{
+	struct inode *dir = NULL;
+	struct dentry *dentry_dir = NULL, *dentry_inode = NULL;
+	struct qstr qstr_dname = QSTR_INIT(darg->dname, darg->dname_len);
+	int ret = 0;
+
+	dir = ext4_iget(sb, darg->parent_ino, EXT4_IGET_NORMAL);
+	if (IS_ERR(dir)) {
+		jbd_debug(1, "Dir with inode %d not found.", darg->parent_ino);
+		dir = NULL;
+		goto out;
+	}
+
+	dentry_dir = d_obtain_alias(dir);
+	if (IS_ERR(dentry_dir)) {
+		jbd_debug(1, "Failed to obtain dentry");
+		dentry_dir = NULL;
+		goto out;
+	}
+
+	dentry_inode = d_alloc(dentry_dir, &qstr_dname);
+	if (!dentry_inode) {
+		jbd_debug(1, "Inode dentry not created.");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = __ext4_link(dir, inode, dentry_inode);
+	/*
+	 * It's possible that link already existed since data blocks
+	 * for the dir in question got persisted before we crashed OR
+	 * we replayed this tag and crashed before the entire replay
+	 * could complete.
+	 */
+	if (ret && ret != -EEXIST) {
+		jbd_debug(1, "Failed to link\n");
+		goto out;
+	}
+
+	ret = 0;
+out:
+	if (dentry_dir) {
+		d_drop(dentry_dir);
+		dput(dentry_dir);
+	} else if (dir) {
+		iput(dir);
+	}
+	if (dentry_inode) {
+		d_drop(dentry_inode);
+		dput(dentry_inode);
+	}
+
+	return ret;
+}
+
+/* Link replay function */
+static int ext4_fc_replay_link(struct super_block *sb, struct ext4_fc_tl *tl,
+			       u8 *val)
+{
+	struct inode *inode;
+	struct dentry_info_args darg;
+	int ret = 0;
+
+	tl_to_darg(&darg, tl, val);
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_LINK, darg.ino,
+			darg.parent_ino, darg.dname_len);
+
+	inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
+	if (IS_ERR(inode)) {
+		jbd_debug(1, "Inode not found.");
+		return 0;
+	}
+
+	ret = ext4_fc_replay_link_internal(sb, &darg, inode);
+	iput(inode);
+	return ret;
+}
+
+/*
+ * Record all the modified inodes during replay. We use this later to setup
+ * block bitmaps correctly.
+ */
+static int ext4_fc_record_modified_inode(struct super_block *sb, int ino)
+{
+	struct ext4_fc_replay_state *state;
+	int i;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	for (i = 0; i < state->fc_modified_inodes_used; i++)
+		if (state->fc_modified_inodes[i] == ino)
+			return 0;
+	if (state->fc_modified_inodes_used == state->fc_modified_inodes_size) {
+		int *fc_modified_inodes;
+
+		fc_modified_inodes = krealloc(state->fc_modified_inodes,
+				sizeof(int) * (state->fc_modified_inodes_size +
+				EXT4_FC_REPLAY_REALLOC_INCREMENT),
+				GFP_KERNEL);
+		if (!fc_modified_inodes)
+			return -ENOMEM;
+		state->fc_modified_inodes = fc_modified_inodes;
+		state->fc_modified_inodes_size +=
+			EXT4_FC_REPLAY_REALLOC_INCREMENT;
+	}
+	state->fc_modified_inodes[state->fc_modified_inodes_used++] = ino;
+	return 0;
+}
+
+/*
+ * Inode replay function
+ */
+static int ext4_fc_replay_inode(struct super_block *sb, struct ext4_fc_tl *tl,
+				u8 *val)
+{
+	struct ext4_fc_inode fc_inode;
+	struct ext4_inode *raw_inode;
+	struct ext4_inode *raw_fc_inode;
+	struct inode *inode = NULL;
+	struct ext4_iloc iloc;
+	int inode_len, ino, ret, tag = le16_to_cpu(tl->fc_tag);
+	struct ext4_extent_header *eh;
+
+	memcpy(&fc_inode, val, sizeof(fc_inode));
+
+	ino = le32_to_cpu(fc_inode.fc_ino);
+	trace_ext4_fc_replay(sb, tag, ino, 0, 0);
+
+	inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
+	if (!IS_ERR(inode)) {
+		ext4_ext_clear_bb(inode);
+		iput(inode);
+	}
+	inode = NULL;
+
+	ret = ext4_fc_record_modified_inode(sb, ino);
+	if (ret)
+		goto out;
+
+	raw_fc_inode = (struct ext4_inode *)
+		(val + offsetof(struct ext4_fc_inode, fc_raw_inode));
+	ret = ext4_get_fc_inode_loc(sb, ino, &iloc);
+	if (ret)
+		goto out;
+
+	inode_len = le16_to_cpu(tl->fc_len) - sizeof(struct ext4_fc_inode);
+	raw_inode = ext4_raw_inode(&iloc);
+
+	memcpy(raw_inode, raw_fc_inode, offsetof(struct ext4_inode, i_block));
+	memcpy(&raw_inode->i_generation, &raw_fc_inode->i_generation,
+		inode_len - offsetof(struct ext4_inode, i_generation));
+	if (le32_to_cpu(raw_inode->i_flags) & EXT4_EXTENTS_FL) {
+		eh = (struct ext4_extent_header *)(&raw_inode->i_block[0]);
+		if (eh->eh_magic != EXT4_EXT_MAGIC) {
+			memset(eh, 0, sizeof(*eh));
+			eh->eh_magic = EXT4_EXT_MAGIC;
+			eh->eh_max = cpu_to_le16(
+				(sizeof(raw_inode->i_block) -
+				 sizeof(struct ext4_extent_header))
+				 / sizeof(struct ext4_extent));
+		}
+	} else if (le32_to_cpu(raw_inode->i_flags) & EXT4_INLINE_DATA_FL) {
+		memcpy(raw_inode->i_block, raw_fc_inode->i_block,
+			sizeof(raw_inode->i_block));
+	}
+
+	/* Immediately update the inode on disk. */
+	ret = ext4_handle_dirty_metadata(NULL, NULL, iloc.bh);
+	if (ret)
+		goto out;
+	ret = sync_dirty_buffer(iloc.bh);
+	if (ret)
+		goto out;
+	ret = ext4_mark_inode_used(sb, ino);
+	if (ret)
+		goto out;
+
+	/* Given that we just wrote the inode on disk, this SHOULD succeed. */
+	inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
+	if (IS_ERR(inode)) {
+		jbd_debug(1, "Inode not found.");
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Our allocator could have made different decisions than before
+	 * crashing. This should be fixed but until then, we calculate
+	 * the number of blocks the inode.
+	 */
+	ext4_ext_replay_set_iblocks(inode);
+
+	inode->i_generation = le32_to_cpu(ext4_raw_inode(&iloc)->i_generation);
+	ext4_reset_inode_seed(inode);
+
+	ext4_inode_csum_set(inode, ext4_raw_inode(&iloc), EXT4_I(inode));
+	ret = ext4_handle_dirty_metadata(NULL, NULL, iloc.bh);
+	sync_dirty_buffer(iloc.bh);
+	brelse(iloc.bh);
+out:
+	iput(inode);
+	if (!ret)
+		blkdev_issue_flush(sb->s_bdev, GFP_KERNEL);
+
+	return 0;
+}
+
+/*
+ * Dentry create replay function.
+ *
+ * EXT4_FC_TAG_CREAT is preceded by EXT4_FC_TAG_INODE_FULL. Which means, the
+ * inode for which we are trying to create a dentry here, should already have
+ * been replayed before we start here.
+ */
+static int ext4_fc_replay_create(struct super_block *sb, struct ext4_fc_tl *tl,
+				 u8 *val)
+{
+	int ret = 0;
+	struct inode *inode = NULL;
+	struct inode *dir = NULL;
+	struct dentry_info_args darg;
+
+	tl_to_darg(&darg, tl, val);
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_CREAT, darg.ino,
+			darg.parent_ino, darg.dname_len);
+
+	/* This takes care of update group descriptor and other metadata */
+	ret = ext4_mark_inode_used(sb, darg.ino);
+	if (ret)
+		goto out;
+
+	inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
+	if (IS_ERR(inode)) {
+		jbd_debug(1, "inode %d not found.", darg.ino);
+		inode = NULL;
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (S_ISDIR(inode->i_mode)) {
+		/*
+		 * If we are creating a directory, we need to make sure that the
+		 * dot and dot dot dirents are setup properly.
+		 */
+		dir = ext4_iget(sb, darg.parent_ino, EXT4_IGET_NORMAL);
+		if (IS_ERR(dir)) {
+			jbd_debug(1, "Dir %d not found.", darg.ino);
+			goto out;
+		}
+		ret = ext4_init_new_dir(NULL, dir, inode);
+		iput(dir);
+		if (ret) {
+			ret = 0;
+			goto out;
+		}
+	}
+	ret = ext4_fc_replay_link_internal(sb, &darg, inode);
+	if (ret)
+		goto out;
+	set_nlink(inode, 1);
+	ext4_mark_inode_dirty(NULL, inode);
+out:
+	if (inode)
+		iput(inode);
+	return ret;
+}
+
+/*
+ * Record physical disk regions which are in use as per fast commit area,
+ * and used by inodes during replay phase. Our simple replay phase
+ * allocator excludes these regions from allocation.
+ */
+int ext4_fc_record_regions(struct super_block *sb, int ino,
+		ext4_lblk_t lblk, ext4_fsblk_t pblk, int len, int replay)
+{
+	struct ext4_fc_replay_state *state;
+	struct ext4_fc_alloc_region *region;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	/*
+	 * during replay phase, the fc_regions_valid may not same as
+	 * fc_regions_used, update it when do new additions.
+	 */
+	if (replay && state->fc_regions_used != state->fc_regions_valid)
+		state->fc_regions_used = state->fc_regions_valid;
+	if (state->fc_regions_used == state->fc_regions_size) {
+		struct ext4_fc_alloc_region *fc_regions;
+
+		fc_regions = krealloc(state->fc_regions,
+				      sizeof(struct ext4_fc_alloc_region) *
+				      (state->fc_regions_size +
+				       EXT4_FC_REPLAY_REALLOC_INCREMENT),
+				      GFP_KERNEL);
+		if (!fc_regions)
+			return -ENOMEM;
+		state->fc_regions_size +=
+			EXT4_FC_REPLAY_REALLOC_INCREMENT;
+		state->fc_regions = fc_regions;
+	}
+	region = &state->fc_regions[state->fc_regions_used++];
+	region->ino = ino;
+	region->lblk = lblk;
+	region->pblk = pblk;
+	region->len = len;
+
+	if (replay)
+		state->fc_regions_valid++;
+
+	return 0;
+}
+
+/* Replay add range tag */
+static int ext4_fc_replay_add_range(struct super_block *sb,
+				    struct ext4_fc_tl *tl, u8 *val)
+{
+	struct ext4_fc_add_range fc_add_ex;
+	struct ext4_extent newex, *ex;
+	struct inode *inode;
+	ext4_lblk_t start, cur;
+	int remaining, len;
+	ext4_fsblk_t start_pblk;
+	struct ext4_map_blocks map;
+	struct ext4_ext_path *path = NULL;
+	int ret;
+
+	memcpy(&fc_add_ex, val, sizeof(fc_add_ex));
+	ex = (struct ext4_extent *)&fc_add_ex.fc_ex;
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_ADD_RANGE,
+		le32_to_cpu(fc_add_ex.fc_ino), le32_to_cpu(ex->ee_block),
+		ext4_ext_get_actual_len(ex));
+
+	inode = ext4_iget(sb, le32_to_cpu(fc_add_ex.fc_ino), EXT4_IGET_NORMAL);
+	if (IS_ERR(inode)) {
+		jbd_debug(1, "Inode not found.");
+		return 0;
+	}
+
+	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+	if (ret)
+		goto out;
+
+	start = le32_to_cpu(ex->ee_block);
+	start_pblk = ext4_ext_pblock(ex);
+	len = ext4_ext_get_actual_len(ex);
+
+	cur = start;
+	remaining = len;
+	jbd_debug(1, "ADD_RANGE, lblk %d, pblk %lld, len %d, unwritten %d, inode %ld\n",
+		  start, start_pblk, len, ext4_ext_is_unwritten(ex),
+		  inode->i_ino);
+
+	while (remaining > 0) {
+		map.m_lblk = cur;
+		map.m_len = remaining;
+		map.m_pblk = 0;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+
+		if (ret < 0)
+			goto out;
+
+		if (ret == 0) {
+			/* Range is not mapped */
+			path = ext4_find_extent(inode, cur, NULL, 0);
+			if (IS_ERR(path))
+				goto out;
+			memset(&newex, 0, sizeof(newex));
+			newex.ee_block = cpu_to_le32(cur);
+			ext4_ext_store_pblock(
+				&newex, start_pblk + cur - start);
+			newex.ee_len = cpu_to_le16(map.m_len);
+			if (ext4_ext_is_unwritten(ex))
+				ext4_ext_mark_unwritten(&newex);
+			down_write(&EXT4_I(inode)->i_data_sem);
+			ret = ext4_ext_insert_extent(
+				NULL, inode, &path, &newex, 0);
+			up_write((&EXT4_I(inode)->i_data_sem));
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			if (ret)
+				goto out;
+			goto next;
+		}
+
+		if (start_pblk + cur - start != map.m_pblk) {
+			/*
+			 * Logical to physical mapping changed. This can happen
+			 * if this range was removed and then reallocated to
+			 * map to new physical blocks during a fast commit.
+			 */
+			ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
+					ext4_ext_is_unwritten(ex),
+					start_pblk + cur - start);
+			if (ret)
+				goto out;
+			/*
+			 * Mark the old blocks as free since they aren't used
+			 * anymore. We maintain an array of all the modified
+			 * inodes. In case these blocks are still used at either
+			 * a different logical range in the same inode or in
+			 * some different inode, we will mark them as allocated
+			 * at the end of the FC replay using our array of
+			 * modified inodes.
+			 */
+			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
+			goto next;
+		}
+
+		/* Range is mapped and needs a state change */
+		jbd_debug(1, "Converting from %ld to %d %lld",
+				map.m_flags & EXT4_MAP_UNWRITTEN,
+			ext4_ext_is_unwritten(ex), map.m_pblk);
+		ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
+					ext4_ext_is_unwritten(ex), map.m_pblk);
+		if (ret)
+			goto out;
+		/*
+		 * We may have split the extent tree while toggling the state.
+		 * Try to shrink the extent tree now.
+		 */
+		ext4_ext_replay_shrink_inode(inode, start + len);
+next:
+		cur += map.m_len;
+		remaining -= map.m_len;
+	}
+	ext4_ext_replay_shrink_inode(inode, i_size_read(inode) >>
+					sb->s_blocksize_bits);
+out:
+	iput(inode);
+	return 0;
+}
+
+/* Replay DEL_RANGE tag */
+static int
+ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl,
+			 u8 *val)
+{
+	struct inode *inode;
+	struct ext4_fc_del_range lrange;
+	struct ext4_map_blocks map;
+	ext4_lblk_t cur, remaining;
+	int ret;
+
+	memcpy(&lrange, val, sizeof(lrange));
+	cur = le32_to_cpu(lrange.fc_lblk);
+	remaining = le32_to_cpu(lrange.fc_len);
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_DEL_RANGE,
+		le32_to_cpu(lrange.fc_ino), cur, remaining);
+
+	inode = ext4_iget(sb, le32_to_cpu(lrange.fc_ino), EXT4_IGET_NORMAL);
+	if (IS_ERR(inode)) {
+		jbd_debug(1, "Inode %d not found", le32_to_cpu(lrange.fc_ino));
+		return 0;
+	}
+
+	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+	if (ret)
+		goto out;
+
+	jbd_debug(1, "DEL_RANGE, inode %ld, lblk %d, len %d\n",
+			inode->i_ino, le32_to_cpu(lrange.fc_lblk),
+			le32_to_cpu(lrange.fc_len));
+	while (remaining > 0) {
+		map.m_lblk = cur;
+		map.m_len = remaining;
+
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0)
+			goto out;
+		if (ret > 0) {
+			remaining -= ret;
+			cur += ret;
+			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
+		} else {
+			remaining -= map.m_len;
+			cur += map.m_len;
+		}
+	}
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	ret = ext4_ext_remove_space(inode, le32_to_cpu(lrange.fc_lblk),
+				le32_to_cpu(lrange.fc_lblk) +
+				le32_to_cpu(lrange.fc_len) - 1);
+	up_write(&EXT4_I(inode)->i_data_sem);
+	if (ret)
+		goto out;
+	ext4_ext_replay_shrink_inode(inode,
+		i_size_read(inode) >> sb->s_blocksize_bits);
+	ext4_mark_inode_dirty(NULL, inode);
+out:
+	iput(inode);
+	return 0;
+}
+
+static inline const char *tag2str(u16 tag)
+{
+	switch (tag) {
+	case EXT4_FC_TAG_LINK:
+		return "TAG_ADD_ENTRY";
+	case EXT4_FC_TAG_UNLINK:
+		return "TAG_DEL_ENTRY";
+	case EXT4_FC_TAG_ADD_RANGE:
+		return "TAG_ADD_RANGE";
+	case EXT4_FC_TAG_CREAT:
+		return "TAG_CREAT_DENTRY";
+	case EXT4_FC_TAG_DEL_RANGE:
+		return "TAG_DEL_RANGE";
+	case EXT4_FC_TAG_INODE:
+		return "TAG_INODE";
+	case EXT4_FC_TAG_PAD:
+		return "TAG_PAD";
+	case EXT4_FC_TAG_TAIL:
+		return "TAG_TAIL";
+	case EXT4_FC_TAG_HEAD:
+		return "TAG_HEAD";
+	default:
+		return "TAG_ERROR";
+	}
+}
+
+static void ext4_fc_set_bitmaps_and_counters(struct super_block *sb)
+{
+	struct ext4_fc_replay_state *state;
+	struct inode *inode;
+	struct ext4_ext_path *path = NULL;
+	struct ext4_map_blocks map;
+	int i, ret, j;
+	ext4_lblk_t cur, end;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	for (i = 0; i < state->fc_modified_inodes_used; i++) {
+		inode = ext4_iget(sb, state->fc_modified_inodes[i],
+			EXT4_IGET_NORMAL);
+		if (IS_ERR(inode)) {
+			jbd_debug(1, "Inode %d not found.",
+				state->fc_modified_inodes[i]);
+			continue;
+		}
+		cur = 0;
+		end = EXT_MAX_BLOCKS;
+		while (cur < end) {
+			map.m_lblk = cur;
+			map.m_len = end - cur;
+
+			ret = ext4_map_blocks(NULL, inode, &map, 0);
+			if (ret < 0)
+				break;
+
+			if (ret > 0) {
+				path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
+				if (!IS_ERR(path)) {
+					for (j = 0; j < path->p_depth; j++)
+						ext4_mb_mark_bb(inode->i_sb,
+							path[j].p_block, 1, 1);
+					ext4_ext_drop_refs(path);
+					kfree(path);
+				}
+				cur += ret;
+				ext4_mb_mark_bb(inode->i_sb, map.m_pblk,
+							map.m_len, 1);
+			} else {
+				cur = cur + (map.m_len ? map.m_len : 1);
+			}
+		}
+		iput(inode);
+	}
+}
+
+/*
+ * Check if block is in excluded regions for block allocation. The simple
+ * allocator that runs during replay phase is calls this function to see
+ * if it is okay to use a block.
+ */
+bool ext4_fc_replay_check_excluded(struct super_block *sb, ext4_fsblk_t blk)
+{
+	int i;
+	struct ext4_fc_replay_state *state;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	for (i = 0; i < state->fc_regions_valid; i++) {
+		if (state->fc_regions[i].ino == 0 ||
+			state->fc_regions[i].len == 0)
+			continue;
+		if (blk >= state->fc_regions[i].pblk &&
+		    blk < state->fc_regions[i].pblk + state->fc_regions[i].len)
+			return true;
+	}
+	return false;
+}
+
+/* Cleanup function called after replay */
+void ext4_fc_replay_cleanup(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	sbi->s_mount_state &= ~EXT4_FC_REPLAY;
+	kfree(sbi->s_fc_replay_state.fc_regions);
+	kfree(sbi->s_fc_replay_state.fc_modified_inodes);
+}
+
+/*
+ * Recovery Scan phase handler
+ *
+ * This function is called during the scan phase and is responsible
+ * for doing following things:
+ * - Make sure the fast commit area has valid tags for replay
+ * - Count number of tags that need to be replayed by the replay handler
+ * - Verify CRC
+ * - Create a list of excluded blocks for allocation during replay phase
+ *
+ * This function returns JBD2_FC_REPLAY_CONTINUE to indicate that SCAN is
+ * incomplete and JBD2 should send more blocks. It returns JBD2_FC_REPLAY_STOP
+ * to indicate that scan has finished and JBD2 can now start replay phase.
+ * It returns a negative error to indicate that there was an error. At the end
+ * of a successful scan phase, sbi->s_fc_replay_state.fc_replay_num_tags is set
+ * to indicate the number of tags that need to replayed during the replay phase.
+ */
+static int ext4_fc_replay_scan(journal_t *journal,
+				struct buffer_head *bh, int off,
+				tid_t expected_tid)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_replay_state *state;
+	int ret = JBD2_FC_REPLAY_CONTINUE;
+	struct ext4_fc_add_range ext;
+	struct ext4_fc_tl tl;
+	struct ext4_fc_tail tail;
+	__u8 *start, *end, *cur, *val;
+	struct ext4_fc_head head;
+	struct ext4_extent *ex;
+
+	state = &sbi->s_fc_replay_state;
+
+	start = (u8 *)bh->b_data;
+	end = (__u8 *)bh->b_data + journal->j_blocksize - 1;
+
+	if (state->fc_replay_expected_off == 0) {
+		state->fc_cur_tag = 0;
+		state->fc_replay_num_tags = 0;
+		state->fc_crc = 0;
+		state->fc_regions = NULL;
+		state->fc_regions_valid = state->fc_regions_used =
+			state->fc_regions_size = 0;
+		/* Check if we can stop early */
+		if (le16_to_cpu(((struct ext4_fc_tl *)start)->fc_tag)
+			!= EXT4_FC_TAG_HEAD)
+			return 0;
+	}
+
+	if (off != state->fc_replay_expected_off) {
+		ret = -EFSCORRUPTED;
+		goto out_err;
+	}
+
+	state->fc_replay_expected_off++;
+	for (cur = start; cur < end; cur = cur + sizeof(tl) + le16_to_cpu(tl.fc_len)) {
+		memcpy(&tl, cur, sizeof(tl));
+		val = cur + sizeof(tl);
+		jbd_debug(3, "Scan phase, tag:%s, blk %lld\n",
+			  tag2str(le16_to_cpu(tl.fc_tag)), bh->b_blocknr);
+		switch (le16_to_cpu(tl.fc_tag)) {
+		case EXT4_FC_TAG_ADD_RANGE:
+			memcpy(&ext, val, sizeof(ext));
+			ex = (struct ext4_extent *)&ext.fc_ex;
+			ret = ext4_fc_record_regions(sb,
+				le32_to_cpu(ext.fc_ino),
+				le32_to_cpu(ex->ee_block), ext4_ext_pblock(ex),
+				ext4_ext_get_actual_len(ex), 0);
+			if (ret < 0)
+				break;
+			ret = JBD2_FC_REPLAY_CONTINUE;
+			fallthrough;
+		case EXT4_FC_TAG_DEL_RANGE:
+		case EXT4_FC_TAG_LINK:
+		case EXT4_FC_TAG_UNLINK:
+		case EXT4_FC_TAG_CREAT:
+		case EXT4_FC_TAG_INODE:
+		case EXT4_FC_TAG_PAD:
+			state->fc_cur_tag++;
+			state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
+					sizeof(tl) + le16_to_cpu(tl.fc_len));
+			break;
+		case EXT4_FC_TAG_TAIL:
+			state->fc_cur_tag++;
+			memcpy(&tail, val, sizeof(tail));
+			state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
+						sizeof(tl) +
+						offsetof(struct ext4_fc_tail,
+						fc_crc));
+			if (le32_to_cpu(tail.fc_tid) == expected_tid &&
+				le32_to_cpu(tail.fc_crc) == state->fc_crc) {
+				state->fc_replay_num_tags = state->fc_cur_tag;
+				state->fc_regions_valid =
+					state->fc_regions_used;
+			} else {
+				ret = state->fc_replay_num_tags ?
+					JBD2_FC_REPLAY_STOP : -EFSBADCRC;
+			}
+			state->fc_crc = 0;
+			break;
+		case EXT4_FC_TAG_HEAD:
+			memcpy(&head, val, sizeof(head));
+			if (le32_to_cpu(head.fc_features) &
+				~EXT4_FC_SUPPORTED_FEATURES) {
+				ret = -EOPNOTSUPP;
+				break;
+			}
+			if (le32_to_cpu(head.fc_tid) != expected_tid) {
+				ret = JBD2_FC_REPLAY_STOP;
+				break;
+			}
+			state->fc_cur_tag++;
+			state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
+					    sizeof(tl) + le16_to_cpu(tl.fc_len));
+			break;
+		default:
+			ret = state->fc_replay_num_tags ?
+				JBD2_FC_REPLAY_STOP : -ECANCELED;
+		}
+		if (ret < 0 || ret == JBD2_FC_REPLAY_STOP)
+			break;
+	}
+
+out_err:
+	trace_ext4_fc_replay_scan(sb, ret, off);
+	return ret;
+}
+
+/*
+ * Main recovery path entry point.
+ * The meaning of return codes is similar as above.
+ */
+static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
+				enum passtype pass, int off, tid_t expected_tid)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_tl tl;
+	__u8 *start, *end, *cur, *val;
+	int ret = JBD2_FC_REPLAY_CONTINUE;
+	struct ext4_fc_replay_state *state = &sbi->s_fc_replay_state;
+	struct ext4_fc_tail tail;
+
+	if (pass == PASS_SCAN) {
+		state->fc_current_pass = PASS_SCAN;
+		return ext4_fc_replay_scan(journal, bh, off, expected_tid);
+	}
+
+	if (state->fc_current_pass != pass) {
+		state->fc_current_pass = pass;
+		sbi->s_mount_state |= EXT4_FC_REPLAY;
+	}
+	if (!sbi->s_fc_replay_state.fc_replay_num_tags) {
+		jbd_debug(1, "Replay stops\n");
+		ext4_fc_set_bitmaps_and_counters(sb);
+		return 0;
+	}
+
+#ifdef CONFIG_EXT4_DEBUG
+	if (sbi->s_fc_debug_max_replay && off >= sbi->s_fc_debug_max_replay) {
+		pr_warn("Dropping fc block %d because max_replay set\n", off);
+		return JBD2_FC_REPLAY_STOP;
+	}
+#endif
+
+	start = (u8 *)bh->b_data;
+	end = (__u8 *)bh->b_data + journal->j_blocksize - 1;
+
+	for (cur = start; cur < end; cur = cur + sizeof(tl) + le16_to_cpu(tl.fc_len)) {
+		memcpy(&tl, cur, sizeof(tl));
+		val = cur + sizeof(tl);
+
+		if (state->fc_replay_num_tags == 0) {
+			ret = JBD2_FC_REPLAY_STOP;
+			ext4_fc_set_bitmaps_and_counters(sb);
+			break;
+		}
+		jbd_debug(3, "Replay phase, tag:%s\n",
+				tag2str(le16_to_cpu(tl.fc_tag)));
+		state->fc_replay_num_tags--;
+		switch (le16_to_cpu(tl.fc_tag)) {
+		case EXT4_FC_TAG_LINK:
+			ret = ext4_fc_replay_link(sb, &tl, val);
+			break;
+		case EXT4_FC_TAG_UNLINK:
+			ret = ext4_fc_replay_unlink(sb, &tl, val);
+			break;
+		case EXT4_FC_TAG_ADD_RANGE:
+			ret = ext4_fc_replay_add_range(sb, &tl, val);
+			break;
+		case EXT4_FC_TAG_CREAT:
+			ret = ext4_fc_replay_create(sb, &tl, val);
+			break;
+		case EXT4_FC_TAG_DEL_RANGE:
+			ret = ext4_fc_replay_del_range(sb, &tl, val);
+			break;
+		case EXT4_FC_TAG_INODE:
+			ret = ext4_fc_replay_inode(sb, &tl, val);
+			break;
+		case EXT4_FC_TAG_PAD:
+			trace_ext4_fc_replay(sb, EXT4_FC_TAG_PAD, 0,
+					     le16_to_cpu(tl.fc_len), 0);
+			break;
+		case EXT4_FC_TAG_TAIL:
+			trace_ext4_fc_replay(sb, EXT4_FC_TAG_TAIL, 0,
+					     le16_to_cpu(tl.fc_len), 0);
+			memcpy(&tail, val, sizeof(tail));
+			WARN_ON(le32_to_cpu(tail.fc_tid) != expected_tid);
+			break;
+		case EXT4_FC_TAG_HEAD:
+			break;
+		default:
+			trace_ext4_fc_replay(sb, le16_to_cpu(tl.fc_tag), 0,
+					     le16_to_cpu(tl.fc_len), 0);
+			ret = -ECANCELED;
+			break;
+		}
+		if (ret < 0)
+			break;
+		ret = JBD2_FC_REPLAY_CONTINUE;
+	}
+	return ret;
+}
+
+void ext4_fc_init(struct super_block *sb, journal_t *journal)
+{
+	/*
+	 * We set replay callback even if fast commit disabled because we may
+	 * could still have fast commit blocks that need to be replayed even if
+	 * fast commit has now been turned off.
+	 */
+	journal->j_fc_replay_callback = ext4_fc_replay;
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
+		return;
+	journal->j_fc_cleanup_callback = ext4_fc_cleanup;
+}
+
+static const char * const fc_ineligible_reasons[] = {
+	[EXT4_FC_REASON_XATTR] = "Extended attributes changed",
+	[EXT4_FC_REASON_CROSS_RENAME] = "Cross rename",
+	[EXT4_FC_REASON_JOURNAL_FLAG_CHANGE] = "Journal flag changed",
+	[EXT4_FC_REASON_NOMEM] = "Insufficient memory",
+	[EXT4_FC_REASON_SWAP_BOOT] = "Swap boot",
+	[EXT4_FC_REASON_RESIZE] = "Resize",
+	[EXT4_FC_REASON_RENAME_DIR] = "Dir renamed",
+	[EXT4_FC_REASON_FALLOC_RANGE] = "Falloc range op",
+	[EXT4_FC_REASON_INODE_JOURNAL_DATA] = "Data journalling",
+	[EXT4_FC_REASON_ENCRYPTED_FILENAME] = "Encrypted filename",
+};
+
+int ext4_fc_info_show(struct seq_file *seq, void *v)
+{
+	struct ext4_sb_info *sbi = EXT4_SB((struct super_block *)seq->private);
+	struct ext4_fc_stats *stats = &sbi->s_fc_stats;
+	int i;
+
+	if (v != SEQ_START_TOKEN)
+		return 0;
+
+	seq_printf(seq,
+		"fc stats:\n%ld commits\n%ld ineligible\n%ld numblks\n%lluus avg_commit_time\n",
+		   stats->fc_num_commits, stats->fc_ineligible_commits,
+		   stats->fc_numblks,
+		   div_u64(sbi->s_fc_avg_commit_time, 1000));
+	seq_puts(seq, "Ineligible reasons:\n");
+	for (i = 0; i < EXT4_FC_REASON_MAX; i++)
+		seq_printf(seq, "\"%s\":\t%d\n", fc_ineligible_reasons[i],
+			stats->fc_ineligible_reason_count[i]);
+
+	return 0;
+}
+
+int __init ext4_fc_init_dentry_cache(void)
+{
+	ext4_fc_dentry_cachep = KMEM_CACHE(ext4_fc_dentry_update,
+					   SLAB_RECLAIM_ACCOUNT);
+
+	if (ext4_fc_dentry_cachep == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void ext4_fc_destroy_dentry_cache(void)
+{
+	kmem_cache_destroy(ext4_fc_dentry_cachep);
+}
diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h
new file mode 100644
index 000000000..4a5f96a9c
--- /dev/null
+++ b/fs/ext4/fast_commit.h
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __FAST_COMMIT_H__
+#define __FAST_COMMIT_H__
+
+/* Fast commit tags */
+#define EXT4_FC_TAG_ADD_RANGE		0x0001
+#define EXT4_FC_TAG_DEL_RANGE		0x0002
+#define EXT4_FC_TAG_CREAT		0x0003
+#define EXT4_FC_TAG_LINK		0x0004
+#define EXT4_FC_TAG_UNLINK		0x0005
+#define EXT4_FC_TAG_INODE		0x0006
+#define EXT4_FC_TAG_PAD			0x0007
+#define EXT4_FC_TAG_TAIL		0x0008
+#define EXT4_FC_TAG_HEAD		0x0009
+
+#define EXT4_FC_SUPPORTED_FEATURES	0x0
+
+/* On disk fast commit tlv value structures */
+
+/* Fast commit on disk tag length structure */
+struct ext4_fc_tl {
+	__le16 fc_tag;
+	__le16 fc_len;
+};
+
+/* Value structure for tag EXT4_FC_TAG_HEAD. */
+struct ext4_fc_head {
+	__le32 fc_features;
+	__le32 fc_tid;
+};
+
+/* Value structure for EXT4_FC_TAG_ADD_RANGE. */
+struct ext4_fc_add_range {
+	__le32 fc_ino;
+	__u8 fc_ex[12];
+};
+
+/* Value structure for tag EXT4_FC_TAG_DEL_RANGE. */
+struct ext4_fc_del_range {
+	__le32 fc_ino;
+	__le32 fc_lblk;
+	__le32 fc_len;
+};
+
+/*
+ * This is the value structure for tags EXT4_FC_TAG_CREAT, EXT4_FC_TAG_LINK
+ * and EXT4_FC_TAG_UNLINK.
+ */
+struct ext4_fc_dentry_info {
+	__le32 fc_parent_ino;
+	__le32 fc_ino;
+	u8 fc_dname[0];
+};
+
+/* Value structure for EXT4_FC_TAG_INODE and EXT4_FC_TAG_INODE_PARTIAL. */
+struct ext4_fc_inode {
+	__le32 fc_ino;
+	__u8 fc_raw_inode[0];
+};
+
+/* Value structure for tag EXT4_FC_TAG_TAIL. */
+struct ext4_fc_tail {
+	__le32 fc_tid;
+	__le32 fc_crc;
+};
+
+/*
+ * In memory list of dentry updates that are performed on the file
+ * system used by fast commit code.
+ */
+struct ext4_fc_dentry_update {
+	int fcd_op;		/* Type of update create / unlink / link */
+	int fcd_parent;		/* Parent inode number */
+	int fcd_ino;		/* Inode number */
+	struct qstr fcd_name;	/* Dirent name */
+	unsigned char fcd_iname[DNAME_INLINE_LEN];	/* Dirent name string */
+	struct list_head fcd_list;
+};
+
+/*
+ * Fast commit reason codes
+ */
+enum {
+	/*
+	 * Commit status codes:
+	 */
+	EXT4_FC_REASON_OK = 0,
+	EXT4_FC_REASON_INELIGIBLE,
+	EXT4_FC_REASON_ALREADY_COMMITTED,
+	EXT4_FC_REASON_FC_START_FAILED,
+	EXT4_FC_REASON_FC_FAILED,
+
+	/*
+	 * Fast commit ineligiblity reasons:
+	 */
+	EXT4_FC_REASON_XATTR = 0,
+	EXT4_FC_REASON_CROSS_RENAME,
+	EXT4_FC_REASON_JOURNAL_FLAG_CHANGE,
+	EXT4_FC_REASON_NOMEM,
+	EXT4_FC_REASON_SWAP_BOOT,
+	EXT4_FC_REASON_RESIZE,
+	EXT4_FC_REASON_RENAME_DIR,
+	EXT4_FC_REASON_FALLOC_RANGE,
+	EXT4_FC_REASON_INODE_JOURNAL_DATA,
+	EXT4_FC_COMMIT_FAILED,
+	EXT4_FC_REASON_ENCRYPTED_FILENAME,
+	EXT4_FC_REASON_MAX
+};
+
+struct ext4_fc_stats {
+	unsigned int fc_ineligible_reason_count[EXT4_FC_REASON_MAX];
+	unsigned long fc_num_commits;
+	unsigned long fc_ineligible_commits;
+	unsigned long fc_numblks;
+};
+
+#define EXT4_FC_REPLAY_REALLOC_INCREMENT	4
+
+/*
+ * Physical block regions added to different inodes due to fast commit
+ * recovery. These are set during the SCAN phase. During the replay phase,
+ * our allocator excludes these from its allocation. This ensures that
+ * we don't accidentally allocating a block that is going to be used by
+ * another inode.
+ */
+struct ext4_fc_alloc_region {
+	ext4_lblk_t lblk;
+	ext4_fsblk_t pblk;
+	int ino, len;
+};
+
+/*
+ * Fast commit replay state.
+ */
+struct ext4_fc_replay_state {
+	int fc_replay_num_tags;
+	int fc_replay_expected_off;
+	int fc_current_pass;
+	int fc_cur_tag;
+	int fc_crc;
+	struct ext4_fc_alloc_region *fc_regions;
+	int fc_regions_size, fc_regions_used, fc_regions_valid;
+	int *fc_modified_inodes;
+	int fc_modified_inodes_used, fc_modified_inodes_size;
+};
+
+#define region_last(__region) (((__region)->lblk) + ((__region)->len) - 1)
+
+
+#endif /* __FAST_COMMIT_H__ */
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
new file mode 100644
index 000000000..f42cc1fe0
--- /dev/null
+++ b/fs/ext4/file.c
@@ -0,0 +1,940 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/file.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/file.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 fs regular file handling primitives
+ *
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ *	(jj@sunsite.ms.mff.cuni.cz)
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/iomap.h>
+#include <linux/mount.h>
+#include <linux/path.h>
+#include <linux/dax.h>
+#include <linux/quotaops.h>
+#include <linux/pagevec.h>
+#include <linux/uio.h>
+#include <linux/mman.h>
+#include <linux/backing-dev.h>
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "truncate.h"
+
+static bool ext4_dio_supported(struct inode *inode)
+{
+	if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode))
+		return false;
+	if (fsverity_active(inode))
+		return false;
+	if (ext4_should_journal_data(inode))
+		return false;
+	if (ext4_has_inline_data(inode))
+		return false;
+	return true;
+}
+
+static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	ssize_t ret;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock_shared(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock_shared(inode);
+	}
+
+	if (!ext4_dio_supported(inode)) {
+		inode_unlock_shared(inode);
+		/*
+		 * Fallback to buffered I/O if the operation being performed on
+		 * the inode is not supported by direct I/O. The IOCB_DIRECT
+		 * flag needs to be cleared here in order to ensure that the
+		 * direct I/O path within generic_file_read_iter() is not
+		 * taken.
+		 */
+		iocb->ki_flags &= ~IOCB_DIRECT;
+		return generic_file_read_iter(iocb, to);
+	}
+
+	ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL,
+			   is_sync_kiocb(iocb));
+	inode_unlock_shared(inode);
+
+	file_accessed(iocb->ki_filp);
+	return ret;
+}
+
+#ifdef CONFIG_FS_DAX
+static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	ssize_t ret;
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock_shared(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock_shared(inode);
+	}
+	/*
+	 * Recheck under inode lock - at this point we are sure it cannot
+	 * change anymore
+	 */
+	if (!IS_DAX(inode)) {
+		inode_unlock_shared(inode);
+		/* Fallback to buffered IO in case we cannot support DAX */
+		return generic_file_read_iter(iocb, to);
+	}
+	ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
+	inode_unlock_shared(inode);
+
+	file_accessed(iocb->ki_filp);
+	return ret;
+}
+#endif
+
+static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	if (!iov_iter_count(to))
+		return 0; /* skip atime */
+
+#ifdef CONFIG_FS_DAX
+	if (IS_DAX(inode))
+		return ext4_dax_read_iter(iocb, to);
+#endif
+	if (iocb->ki_flags & IOCB_DIRECT)
+		return ext4_dio_read_iter(iocb, to);
+
+	return generic_file_read_iter(iocb, to);
+}
+
+/*
+ * Called when an inode is released. Note that this is different
+ * from ext4_file_open: open gets called at every open, but release
+ * gets called only when /all/ the files are closed.
+ */
+static int ext4_release_file(struct inode *inode, struct file *filp)
+{
+	if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
+		ext4_alloc_da_blocks(inode);
+		ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
+	}
+	/* if we are the last writer on the inode, drop the block reservation */
+	if ((filp->f_mode & FMODE_WRITE) &&
+			(atomic_read(&inode->i_writecount) == 1) &&
+			!EXT4_I(inode)->i_reserved_data_blocks) {
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ext4_discard_preallocations(inode, 0);
+		up_write(&EXT4_I(inode)->i_data_sem);
+	}
+	if (is_dx(inode) && filp->private_data)
+		ext4_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+/*
+ * This tests whether the IO in question is block-aligned or not.
+ * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
+ * are converted to written only after the IO is complete.  Until they are
+ * mapped, these blocks appear as holes, so dio_zero_block() will assume that
+ * it needs to zero out portions of the start and/or end block.  If 2 AIO
+ * threads are at work on the same unwritten block, they must be synchronized
+ * or one thread will zero the other's data, causing corruption.
+ */
+static bool
+ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned long blockmask = sb->s_blocksize - 1;
+
+	if ((pos | iov_iter_alignment(from)) & blockmask)
+		return true;
+
+	return false;
+}
+
+static bool
+ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
+{
+	if (offset + len > i_size_read(inode) ||
+	    offset + len > EXT4_I(inode)->i_disksize)
+		return true;
+	return false;
+}
+
+/* Is IO overwriting allocated and initialized blocks? */
+static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
+{
+	struct ext4_map_blocks map;
+	unsigned int blkbits = inode->i_blkbits;
+	int err, blklen;
+
+	if (pos + len > i_size_read(inode))
+		return false;
+
+	map.m_lblk = pos >> blkbits;
+	map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
+	blklen = map.m_len;
+
+	err = ext4_map_blocks(NULL, inode, &map, 0);
+	/*
+	 * 'err==len' means that all of the blocks have been preallocated,
+	 * regardless of whether they have been initialized or not. To exclude
+	 * unwritten extents, we need to check m_flags.
+	 */
+	return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
+}
+
+static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
+					 struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	ssize_t ret;
+
+	if (unlikely(IS_IMMUTABLE(inode)))
+		return -EPERM;
+
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		return ret;
+
+	/*
+	 * If we have encountered a bitmap-format file, the size limit
+	 * is smaller than s_maxbytes, which is for extent-mapped files.
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+		if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
+			return -EFBIG;
+		iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
+	}
+
+	return iov_iter_count(from);
+}
+
+static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
+{
+	ssize_t ret, count;
+
+	count = ext4_generic_write_checks(iocb, from);
+	if (count <= 0)
+		return count;
+
+	ret = file_modified(iocb->ki_filp);
+	if (ret)
+		return ret;
+	return count;
+}
+
+static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
+					struct iov_iter *from)
+{
+	ssize_t ret;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (iocb->ki_flags & IOCB_NOWAIT)
+		return -EOPNOTSUPP;
+
+	inode_lock(inode);
+	ret = ext4_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	current->backing_dev_info = inode_to_bdi(inode);
+	ret = generic_perform_write(iocb->ki_filp, from, iocb->ki_pos);
+	current->backing_dev_info = NULL;
+
+out:
+	inode_unlock(inode);
+	if (likely(ret > 0)) {
+		iocb->ki_pos += ret;
+		ret = generic_write_sync(iocb, ret);
+	}
+
+	return ret;
+}
+
+static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
+					   ssize_t written, size_t count)
+{
+	handle_t *handle;
+	bool truncate = false;
+	u8 blkbits = inode->i_blkbits;
+	ext4_lblk_t written_blk, end_blk;
+	int ret;
+
+	/*
+	 * Note that EXT4_I(inode)->i_disksize can get extended up to
+	 * inode->i_size while the I/O was running due to writeback of delalloc
+	 * blocks. But, the code in ext4_iomap_alloc() is careful to use
+	 * zeroed/unwritten extents if this is possible; thus we won't leave
+	 * uninitialized blocks in a file even if we didn't succeed in writing
+	 * as much as we intended.
+	 */
+	WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
+	if (offset + count <= EXT4_I(inode)->i_disksize) {
+		/*
+		 * We need to ensure that the inode is removed from the orphan
+		 * list if it has been added prematurely, due to writeback of
+		 * delalloc blocks.
+		 */
+		if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
+			handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+
+			if (IS_ERR(handle)) {
+				ext4_orphan_del(NULL, inode);
+				return PTR_ERR(handle);
+			}
+
+			ext4_orphan_del(handle, inode);
+			ext4_journal_stop(handle);
+		}
+
+		return written;
+	}
+
+	if (written < 0)
+		goto truncate;
+
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+	if (IS_ERR(handle)) {
+		written = PTR_ERR(handle);
+		goto truncate;
+	}
+
+	if (ext4_update_inode_size(inode, offset + written)) {
+		ret = ext4_mark_inode_dirty(handle, inode);
+		if (unlikely(ret)) {
+			written = ret;
+			ext4_journal_stop(handle);
+			goto truncate;
+		}
+	}
+
+	/*
+	 * We may need to truncate allocated but not written blocks beyond EOF.
+	 */
+	written_blk = ALIGN(offset + written, 1 << blkbits);
+	end_blk = ALIGN(offset + count, 1 << blkbits);
+	if (written_blk < end_blk && ext4_can_truncate(inode))
+		truncate = true;
+
+	/*
+	 * Remove the inode from the orphan list if it has been extended and
+	 * everything went OK.
+	 */
+	if (!truncate && inode->i_nlink)
+		ext4_orphan_del(handle, inode);
+	ext4_journal_stop(handle);
+
+	if (truncate) {
+truncate:
+		ext4_truncate_failed_write(inode);
+		/*
+		 * If the truncate operation failed early, then the inode may
+		 * still be on the orphan list. In that case, we need to try
+		 * remove the inode from the in-memory linked list.
+		 */
+		if (inode->i_nlink)
+			ext4_orphan_del(NULL, inode);
+	}
+
+	return written;
+}
+
+static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
+				 int error, unsigned int flags)
+{
+	loff_t pos = iocb->ki_pos;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (error)
+		return error;
+
+	if (size && flags & IOMAP_DIO_UNWRITTEN) {
+		error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
+		if (error < 0)
+			return error;
+	}
+	/*
+	 * If we are extending the file, we have to update i_size here before
+	 * page cache gets invalidated in iomap_dio_rw(). Otherwise racing
+	 * buffered reads could zero out too much from page cache pages. Update
+	 * of on-disk size will happen later in ext4_dio_write_iter() where
+	 * we have enough information to also perform orphan list handling etc.
+	 * Note that we perform all extending writes synchronously under
+	 * i_rwsem held exclusively so i_size update is safe here in that case.
+	 * If the write was not extending, we cannot see pos > i_size here
+	 * because operations reducing i_size like truncate wait for all
+	 * outstanding DIO before updating i_size.
+	 */
+	pos += size;
+	if (pos > i_size_read(inode))
+		i_size_write(inode, pos);
+
+	return 0;
+}
+
+static const struct iomap_dio_ops ext4_dio_write_ops = {
+	.end_io = ext4_dio_write_end_io,
+};
+
+/*
+ * The intention here is to start with shared lock acquired then see if any
+ * condition requires an exclusive inode lock. If yes, then we restart the
+ * whole operation by releasing the shared lock and acquiring exclusive lock.
+ *
+ * - For unaligned_io we never take shared lock as it may cause data corruption
+ *   when two unaligned IO tries to modify the same block e.g. while zeroing.
+ *
+ * - For extending writes case we don't take the shared lock, since it requires
+ *   updating inode i_disksize and/or orphan handling with exclusive lock.
+ *
+ * - shared locking will only be true mostly with overwrites. Otherwise we will
+ *   switch to exclusive i_rwsem lock.
+ */
+static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
+				     bool *ilock_shared, bool *extend)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+	loff_t offset;
+	size_t count;
+	ssize_t ret;
+
+restart:
+	ret = ext4_generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	offset = iocb->ki_pos;
+	count = ret;
+	if (ext4_extending_io(inode, offset, count))
+		*extend = true;
+	/*
+	 * Determine whether the IO operation will overwrite allocated
+	 * and initialized blocks.
+	 * We need exclusive i_rwsem for changing security info
+	 * in file_modified().
+	 */
+	if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
+	     !ext4_overwrite_io(inode, offset, count))) {
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
+		inode_unlock_shared(inode);
+		*ilock_shared = false;
+		inode_lock(inode);
+		goto restart;
+	}
+
+	ret = file_modified(file);
+	if (ret < 0)
+		goto out;
+
+	return count;
+out:
+	if (*ilock_shared)
+		inode_unlock_shared(inode);
+	else
+		inode_unlock(inode);
+	return ret;
+}
+
+static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	ssize_t ret;
+	handle_t *handle;
+	struct inode *inode = file_inode(iocb->ki_filp);
+	loff_t offset = iocb->ki_pos;
+	size_t count = iov_iter_count(from);
+	const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
+	bool extend = false, unaligned_io = false;
+	bool ilock_shared = true;
+
+	/*
+	 * We initially start with shared inode lock unless it is
+	 * unaligned IO which needs exclusive lock anyways.
+	 */
+	if (ext4_unaligned_io(inode, from, offset)) {
+		unaligned_io = true;
+		ilock_shared = false;
+	}
+	/*
+	 * Quick check here without any i_rwsem lock to see if it is extending
+	 * IO. A more reliable check is done in ext4_dio_write_checks() with
+	 * proper locking in place.
+	 */
+	if (offset + count > i_size_read(inode))
+		ilock_shared = false;
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (ilock_shared) {
+			if (!inode_trylock_shared(inode))
+				return -EAGAIN;
+		} else {
+			if (!inode_trylock(inode))
+				return -EAGAIN;
+		}
+	} else {
+		if (ilock_shared)
+			inode_lock_shared(inode);
+		else
+			inode_lock(inode);
+	}
+
+	/* Fallback to buffered I/O if the inode does not support direct I/O. */
+	if (!ext4_dio_supported(inode)) {
+		if (ilock_shared)
+			inode_unlock_shared(inode);
+		else
+			inode_unlock(inode);
+		return ext4_buffered_write_iter(iocb, from);
+	}
+
+	ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
+	if (ret <= 0)
+		return ret;
+
+	/* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
+	if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+	/*
+	 * Make sure inline data cannot be created anymore since we are going
+	 * to allocate blocks for DIO. We know the inode does not have any
+	 * inline data now because ext4_dio_supported() checked for that.
+	 */
+	ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+
+	offset = iocb->ki_pos;
+	count = ret;
+
+	/*
+	 * Unaligned direct IO must be serialized among each other as zeroing
+	 * of partial blocks of two competing unaligned IOs can result in data
+	 * corruption.
+	 *
+	 * So we make sure we don't allow any unaligned IO in flight.
+	 * For IOs where we need not wait (like unaligned non-AIO DIO),
+	 * below inode_dio_wait() may anyway become a no-op, since we start
+	 * with exclusive lock.
+	 */
+	if (unaligned_io)
+		inode_dio_wait(inode);
+
+	if (extend) {
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			goto out;
+		}
+
+		ret = ext4_orphan_add(handle, inode);
+		if (ret) {
+			ext4_journal_stop(handle);
+			goto out;
+		}
+
+		ext4_journal_stop(handle);
+	}
+
+	if (ilock_shared)
+		iomap_ops = &ext4_iomap_overwrite_ops;
+	ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
+			   is_sync_kiocb(iocb) || unaligned_io || extend);
+	if (ret == -ENOTBLK)
+		ret = 0;
+
+	if (extend)
+		ret = ext4_handle_inode_extension(inode, offset, ret, count);
+
+out:
+	if (ilock_shared)
+		inode_unlock_shared(inode);
+	else
+		inode_unlock(inode);
+
+	if (ret >= 0 && iov_iter_count(from)) {
+		ssize_t err;
+		loff_t endbyte;
+
+		offset = iocb->ki_pos;
+		err = ext4_buffered_write_iter(iocb, from);
+		if (err < 0)
+			return err;
+
+		/*
+		 * We need to ensure that the pages within the page cache for
+		 * the range covered by this I/O are written to disk and
+		 * invalidated. This is in attempt to preserve the expected
+		 * direct I/O semantics in the case we fallback to buffered I/O
+		 * to complete off the I/O request.
+		 */
+		ret += err;
+		endbyte = offset + err - 1;
+		err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
+						   offset, endbyte);
+		if (!err)
+			invalidate_mapping_pages(iocb->ki_filp->f_mapping,
+						 offset >> PAGE_SHIFT,
+						 endbyte >> PAGE_SHIFT);
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_FS_DAX
+static ssize_t
+ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	ssize_t ret;
+	size_t count;
+	loff_t offset;
+	handle_t *handle;
+	bool extend = false;
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock(inode);
+	}
+
+	ret = ext4_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	offset = iocb->ki_pos;
+	count = iov_iter_count(from);
+
+	if (offset + count > EXT4_I(inode)->i_disksize) {
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			goto out;
+		}
+
+		ret = ext4_orphan_add(handle, inode);
+		if (ret) {
+			ext4_journal_stop(handle);
+			goto out;
+		}
+
+		extend = true;
+		ext4_journal_stop(handle);
+	}
+
+	ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
+
+	if (extend)
+		ret = ext4_handle_inode_extension(inode, offset, ret, count);
+out:
+	inode_unlock(inode);
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
+	return ret;
+}
+#endif
+
+static ssize_t
+ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+#ifdef CONFIG_FS_DAX
+	if (IS_DAX(inode))
+		return ext4_dax_write_iter(iocb, from);
+#endif
+	if (iocb->ki_flags & IOCB_DIRECT)
+		return ext4_dio_write_iter(iocb, from);
+	else
+		return ext4_buffered_write_iter(iocb, from);
+}
+
+#ifdef CONFIG_FS_DAX
+static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
+		enum page_entry_size pe_size)
+{
+	int error = 0;
+	vm_fault_t result;
+	int retries = 0;
+	handle_t *handle = NULL;
+	struct inode *inode = file_inode(vmf->vma->vm_file);
+	struct super_block *sb = inode->i_sb;
+
+	/*
+	 * We have to distinguish real writes from writes which will result in a
+	 * COW page; COW writes should *not* poke the journal (the file will not
+	 * be changed). Doing so would cause unintended failures when mounted
+	 * read-only.
+	 *
+	 * We check for VM_SHARED rather than vmf->cow_page since the latter is
+	 * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
+	 * other sizes, dax_iomap_fault will handle splitting / fallback so that
+	 * we eventually come back with a COW page.
+	 */
+	bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
+		(vmf->vma->vm_flags & VM_SHARED);
+	pfn_t pfn;
+
+	if (write) {
+		sb_start_pagefault(sb);
+		file_update_time(vmf->vma->vm_file);
+		down_read(&EXT4_I(inode)->i_mmap_sem);
+retry:
+		handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
+					       EXT4_DATA_TRANS_BLOCKS(sb));
+		if (IS_ERR(handle)) {
+			up_read(&EXT4_I(inode)->i_mmap_sem);
+			sb_end_pagefault(sb);
+			return VM_FAULT_SIGBUS;
+		}
+	} else {
+		down_read(&EXT4_I(inode)->i_mmap_sem);
+	}
+	result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
+	if (write) {
+		ext4_journal_stop(handle);
+
+		if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
+		    ext4_should_retry_alloc(sb, &retries))
+			goto retry;
+		/* Handling synchronous page fault? */
+		if (result & VM_FAULT_NEEDDSYNC)
+			result = dax_finish_sync_fault(vmf, pe_size, pfn);
+		up_read(&EXT4_I(inode)->i_mmap_sem);
+		sb_end_pagefault(sb);
+	} else {
+		up_read(&EXT4_I(inode)->i_mmap_sem);
+	}
+
+	return result;
+}
+
+static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
+{
+	return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
+}
+
+static const struct vm_operations_struct ext4_dax_vm_ops = {
+	.fault		= ext4_dax_fault,
+	.huge_fault	= ext4_dax_huge_fault,
+	.page_mkwrite	= ext4_dax_fault,
+	.pfn_mkwrite	= ext4_dax_fault,
+};
+#else
+#define ext4_dax_vm_ops	ext4_file_vm_ops
+#endif
+
+static const struct vm_operations_struct ext4_file_vm_ops = {
+	.fault		= ext4_filemap_fault,
+	.map_pages	= filemap_map_pages,
+	.page_mkwrite   = ext4_page_mkwrite,
+};
+
+static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct dax_device *dax_dev = sbi->s_daxdev;
+
+	if (unlikely(ext4_forced_shutdown(sbi)))
+		return -EIO;
+
+	/*
+	 * We don't support synchronous mappings for non-DAX files and
+	 * for DAX files if underneath dax_device is not synchronous.
+	 */
+	if (!daxdev_mapping_supported(vma, dax_dev))
+		return -EOPNOTSUPP;
+
+	file_accessed(file);
+	if (IS_DAX(file_inode(file))) {
+		vma->vm_ops = &ext4_dax_vm_ops;
+		vma->vm_flags |= VM_HUGEPAGE;
+	} else {
+		vma->vm_ops = &ext4_file_vm_ops;
+	}
+	return 0;
+}
+
+static int ext4_sample_last_mounted(struct super_block *sb,
+				    struct vfsmount *mnt)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct path path;
+	char buf[64], *cp;
+	handle_t *handle;
+	int err;
+
+	if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
+		return 0;
+
+	if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
+		return 0;
+
+	ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
+	/*
+	 * Sample where the filesystem has been mounted and
+	 * store it in the superblock for sysadmin convenience
+	 * when trying to sort through large numbers of block
+	 * devices or filesystem images.
+	 */
+	memset(buf, 0, sizeof(buf));
+	path.mnt = mnt;
+	path.dentry = mnt->mnt_root;
+	cp = d_path(&path, buf, sizeof(buf));
+	err = 0;
+	if (IS_ERR(cp))
+		goto out;
+
+	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+	err = PTR_ERR(handle);
+	if (IS_ERR(handle))
+		goto out;
+	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+	if (err)
+		goto out_journal;
+	strncpy(sbi->s_es->s_last_mounted, cp,
+		sizeof(sbi->s_es->s_last_mounted));
+	ext4_handle_dirty_super(handle, sb);
+out_journal:
+	ext4_journal_stop(handle);
+out:
+	sb_end_intwrite(sb);
+	return err;
+}
+
+static int ext4_file_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
+	if (ret)
+		return ret;
+
+	ret = fscrypt_file_open(inode, filp);
+	if (ret)
+		return ret;
+
+	ret = fsverity_file_open(inode, filp);
+	if (ret)
+		return ret;
+
+	/*
+	 * Set up the jbd2_inode if we are opening the inode for
+	 * writing and the journal is present
+	 */
+	if (filp->f_mode & FMODE_WRITE) {
+		ret = ext4_inode_attach_jinode(inode);
+		if (ret < 0)
+			return ret;
+	}
+
+	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
+	return dquot_file_open(inode, filp);
+}
+
+/*
+ * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
+ * by calling generic_file_llseek_size() with the appropriate maxbytes
+ * value for each.
+ */
+loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	loff_t maxbytes;
+
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
+	else
+		maxbytes = inode->i_sb->s_maxbytes;
+
+	switch (whence) {
+	default:
+		return generic_file_llseek_size(file, offset, whence,
+						maxbytes, i_size_read(inode));
+	case SEEK_HOLE:
+		inode_lock_shared(inode);
+		offset = iomap_seek_hole(inode, offset,
+					 &ext4_iomap_report_ops);
+		inode_unlock_shared(inode);
+		break;
+	case SEEK_DATA:
+		inode_lock_shared(inode);
+		offset = iomap_seek_data(inode, offset,
+					 &ext4_iomap_report_ops);
+		inode_unlock_shared(inode);
+		break;
+	}
+
+	if (offset < 0)
+		return offset;
+	return vfs_setpos(file, offset, maxbytes);
+}
+
+const struct file_operations ext4_file_operations = {
+	.llseek		= ext4_llseek,
+	.read_iter	= ext4_file_read_iter,
+	.write_iter	= ext4_file_write_iter,
+	.iopoll		= iomap_dio_iopoll,
+	.unlocked_ioctl = ext4_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext4_compat_ioctl,
+#endif
+	.mmap		= ext4_file_mmap,
+	.mmap_supported_flags = MAP_SYNC,
+	.open		= ext4_file_open,
+	.release	= ext4_release_file,
+	.fsync		= ext4_sync_file,
+	.get_unmapped_area = thp_get_unmapped_area,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
+	.fallocate	= ext4_fallocate,
+};
+
+const struct inode_operations ext4_file_inode_operations = {
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_file_getattr,
+	.listxattr	= ext4_listxattr,
+	.get_acl	= ext4_get_acl,
+	.set_acl	= ext4_set_acl,
+	.fiemap		= ext4_fiemap,
+};
+
diff --git a/fs/ext4/fsmap.c b/fs/ext4/fsmap.c
new file mode 100644
index 000000000..cdf9bfe10
--- /dev/null
+++ b/fs/ext4/fsmap.c
@@ -0,0 +1,718 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#include "ext4.h"
+#include <linux/fsmap.h>
+#include "fsmap.h"
+#include "mballoc.h"
+#include <linux/sort.h>
+#include <linux/list_sort.h>
+#include <trace/events/ext4.h>
+
+/* Convert an ext4_fsmap to an fsmap. */
+void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
+			      struct ext4_fsmap *src)
+{
+	dest->fmr_device = src->fmr_device;
+	dest->fmr_flags = src->fmr_flags;
+	dest->fmr_physical = src->fmr_physical << sb->s_blocksize_bits;
+	dest->fmr_owner = src->fmr_owner;
+	dest->fmr_offset = 0;
+	dest->fmr_length = src->fmr_length << sb->s_blocksize_bits;
+	dest->fmr_reserved[0] = 0;
+	dest->fmr_reserved[1] = 0;
+	dest->fmr_reserved[2] = 0;
+}
+
+/* Convert an fsmap to an ext4_fsmap. */
+void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
+			    struct fsmap *src)
+{
+	dest->fmr_device = src->fmr_device;
+	dest->fmr_flags = src->fmr_flags;
+	dest->fmr_physical = src->fmr_physical >> sb->s_blocksize_bits;
+	dest->fmr_owner = src->fmr_owner;
+	dest->fmr_length = src->fmr_length >> sb->s_blocksize_bits;
+}
+
+/* getfsmap query state */
+struct ext4_getfsmap_info {
+	struct ext4_fsmap_head	*gfi_head;
+	ext4_fsmap_format_t	gfi_formatter;	/* formatting fn */
+	void			*gfi_format_arg;/* format buffer */
+	ext4_fsblk_t		gfi_next_fsblk;	/* next fsblock we expect */
+	u32			gfi_dev;	/* device id */
+	ext4_group_t		gfi_agno;	/* bg number, if applicable */
+	struct ext4_fsmap	gfi_low;	/* low rmap key */
+	struct ext4_fsmap	gfi_high;	/* high rmap key */
+	struct ext4_fsmap	gfi_lastfree;	/* free ext at end of last bg */
+	struct list_head	gfi_meta_list;	/* fixed metadata list */
+	bool			gfi_last;	/* last extent? */
+};
+
+/* Associate a device with a getfsmap handler. */
+struct ext4_getfsmap_dev {
+	int			(*gfd_fn)(struct super_block *sb,
+				      struct ext4_fsmap *keys,
+				      struct ext4_getfsmap_info *info);
+	u32			gfd_dev;
+};
+
+/* Compare two getfsmap device handlers. */
+static int ext4_getfsmap_dev_compare(const void *p1, const void *p2)
+{
+	const struct ext4_getfsmap_dev *d1 = p1;
+	const struct ext4_getfsmap_dev *d2 = p2;
+
+	return d1->gfd_dev - d2->gfd_dev;
+}
+
+/* Compare a record against our starting point */
+static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info,
+					     struct ext4_fsmap *rec)
+{
+	return rec->fmr_physical < info->gfi_low.fmr_physical;
+}
+
+/*
+ * Format a reverse mapping for getfsmap, having translated rm_startblock
+ * into the appropriate daddr units.
+ */
+static int ext4_getfsmap_helper(struct super_block *sb,
+				struct ext4_getfsmap_info *info,
+				struct ext4_fsmap *rec)
+{
+	struct ext4_fsmap fmr;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_fsblk_t rec_fsblk = rec->fmr_physical;
+	ext4_group_t agno;
+	ext4_grpblk_t cno;
+	int error;
+
+	if (fatal_signal_pending(current))
+		return -EINTR;
+
+	/*
+	 * Filter out records that start before our startpoint, if the
+	 * caller requested that.
+	 */
+	if (ext4_getfsmap_rec_before_low_key(info, rec)) {
+		rec_fsblk += rec->fmr_length;
+		if (info->gfi_next_fsblk < rec_fsblk)
+			info->gfi_next_fsblk = rec_fsblk;
+		return EXT4_QUERY_RANGE_CONTINUE;
+	}
+
+	/* Are we just counting mappings? */
+	if (info->gfi_head->fmh_count == 0) {
+		if (info->gfi_head->fmh_entries == UINT_MAX)
+			return EXT4_QUERY_RANGE_ABORT;
+
+		if (rec_fsblk > info->gfi_next_fsblk)
+			info->gfi_head->fmh_entries++;
+
+		if (info->gfi_last)
+			return EXT4_QUERY_RANGE_CONTINUE;
+
+		info->gfi_head->fmh_entries++;
+
+		rec_fsblk += rec->fmr_length;
+		if (info->gfi_next_fsblk < rec_fsblk)
+			info->gfi_next_fsblk = rec_fsblk;
+		return EXT4_QUERY_RANGE_CONTINUE;
+	}
+
+	/*
+	 * If the record starts past the last physical block we saw,
+	 * then we've found a gap.  Report the gap as being owned by
+	 * whatever the caller specified is the missing owner.
+	 */
+	if (rec_fsblk > info->gfi_next_fsblk) {
+		if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
+			return EXT4_QUERY_RANGE_ABORT;
+
+		ext4_get_group_no_and_offset(sb, info->gfi_next_fsblk,
+				&agno, &cno);
+		trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno,
+				EXT4_C2B(sbi, cno),
+				rec_fsblk - info->gfi_next_fsblk,
+				EXT4_FMR_OWN_UNKNOWN);
+
+		fmr.fmr_device = info->gfi_dev;
+		fmr.fmr_physical = info->gfi_next_fsblk;
+		fmr.fmr_owner = EXT4_FMR_OWN_UNKNOWN;
+		fmr.fmr_length = rec_fsblk - info->gfi_next_fsblk;
+		fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
+		error = info->gfi_formatter(&fmr, info->gfi_format_arg);
+		if (error)
+			return error;
+		info->gfi_head->fmh_entries++;
+	}
+
+	if (info->gfi_last)
+		goto out;
+
+	/* Fill out the extent we found */
+	if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
+		return EXT4_QUERY_RANGE_ABORT;
+
+	ext4_get_group_no_and_offset(sb, rec_fsblk, &agno, &cno);
+	trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, EXT4_C2B(sbi, cno),
+			rec->fmr_length, rec->fmr_owner);
+
+	fmr.fmr_device = info->gfi_dev;
+	fmr.fmr_physical = rec_fsblk;
+	fmr.fmr_owner = rec->fmr_owner;
+	fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
+	fmr.fmr_length = rec->fmr_length;
+	error = info->gfi_formatter(&fmr, info->gfi_format_arg);
+	if (error)
+		return error;
+	info->gfi_head->fmh_entries++;
+
+out:
+	rec_fsblk += rec->fmr_length;
+	if (info->gfi_next_fsblk < rec_fsblk)
+		info->gfi_next_fsblk = rec_fsblk;
+	return EXT4_QUERY_RANGE_CONTINUE;
+}
+
+static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr)
+{
+	return fmr->fmr_physical + fmr->fmr_length;
+}
+
+/* Transform a blockgroup's free record into a fsmap */
+static int ext4_getfsmap_datadev_helper(struct super_block *sb,
+					ext4_group_t agno, ext4_grpblk_t start,
+					ext4_grpblk_t len, void *priv)
+{
+	struct ext4_fsmap irec;
+	struct ext4_getfsmap_info *info = priv;
+	struct ext4_fsmap *p;
+	struct ext4_fsmap *tmp;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_fsblk_t fsb;
+	ext4_fsblk_t fslen;
+	int error;
+
+	fsb = (EXT4_C2B(sbi, start) + ext4_group_first_block_no(sb, agno));
+	fslen = EXT4_C2B(sbi, len);
+
+	/* If the retained free extent record is set... */
+	if (info->gfi_lastfree.fmr_owner) {
+		/* ...and abuts this one, lengthen it and return. */
+		if (ext4_fsmap_next_pblk(&info->gfi_lastfree) == fsb) {
+			info->gfi_lastfree.fmr_length += fslen;
+			return 0;
+		}
+
+		/*
+		 * There's a gap between the two free extents; emit the
+		 * retained extent prior to merging the meta_list.
+		 */
+		error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
+		if (error)
+			return error;
+		info->gfi_lastfree.fmr_owner = 0;
+	}
+
+	/* Merge in any relevant extents from the meta_list */
+	list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {
+		if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) {
+			list_del(&p->fmr_list);
+			kfree(p);
+		} else if (p->fmr_physical < fsb) {
+			error = ext4_getfsmap_helper(sb, info, p);
+			if (error)
+				return error;
+
+			list_del(&p->fmr_list);
+			kfree(p);
+		}
+	}
+
+	irec.fmr_device = 0;
+	irec.fmr_physical = fsb;
+	irec.fmr_length = fslen;
+	irec.fmr_owner = EXT4_FMR_OWN_FREE;
+	irec.fmr_flags = 0;
+
+	/* If this is a free extent at the end of a bg, buffer it. */
+	if (ext4_fsmap_next_pblk(&irec) ==
+			ext4_group_first_block_no(sb, agno + 1)) {
+		info->gfi_lastfree = irec;
+		return 0;
+	}
+
+	/* Otherwise, emit it */
+	return ext4_getfsmap_helper(sb, info, &irec);
+}
+
+/* Execute a getfsmap query against the log device. */
+static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys,
+				struct ext4_getfsmap_info *info)
+{
+	journal_t *journal = EXT4_SB(sb)->s_journal;
+	struct ext4_fsmap irec;
+
+	/* Set up search keys */
+	info->gfi_low = keys[0];
+	info->gfi_low.fmr_length = 0;
+
+	memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
+
+	trace_ext4_fsmap_low_key(sb, info->gfi_dev, 0,
+			info->gfi_low.fmr_physical,
+			info->gfi_low.fmr_length,
+			info->gfi_low.fmr_owner);
+
+	trace_ext4_fsmap_high_key(sb, info->gfi_dev, 0,
+			info->gfi_high.fmr_physical,
+			info->gfi_high.fmr_length,
+			info->gfi_high.fmr_owner);
+
+	if (keys[0].fmr_physical > 0)
+		return 0;
+
+	/* Fabricate an rmap entry for the external log device. */
+	irec.fmr_physical = journal->j_blk_offset;
+	irec.fmr_length = journal->j_total_len;
+	irec.fmr_owner = EXT4_FMR_OWN_LOG;
+	irec.fmr_flags = 0;
+
+	return ext4_getfsmap_helper(sb, info, &irec);
+}
+
+/* Helper to fill out an ext4_fsmap. */
+static inline int ext4_getfsmap_fill(struct list_head *meta_list,
+				     ext4_fsblk_t fsb, ext4_fsblk_t len,
+				     uint64_t owner)
+{
+	struct ext4_fsmap *fsm;
+
+	fsm = kmalloc(sizeof(*fsm), GFP_NOFS);
+	if (!fsm)
+		return -ENOMEM;
+	fsm->fmr_device = 0;
+	fsm->fmr_flags = 0;
+	fsm->fmr_physical = fsb;
+	fsm->fmr_owner = owner;
+	fsm->fmr_length = len;
+	list_add_tail(&fsm->fmr_list, meta_list);
+
+	return 0;
+}
+
+/*
+ * This function returns the number of file system metadata blocks at
+ * the beginning of a block group, including the reserved gdt blocks.
+ */
+static unsigned int ext4_getfsmap_find_sb(struct super_block *sb,
+					  ext4_group_t agno,
+					  struct list_head *meta_list)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_fsblk_t fsb = ext4_group_first_block_no(sb, agno);
+	ext4_fsblk_t len;
+	unsigned long first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
+	unsigned long metagroup = agno / EXT4_DESC_PER_BLOCK(sb);
+	int error;
+
+	/* Record the superblock. */
+	if (ext4_bg_has_super(sb, agno)) {
+		error = ext4_getfsmap_fill(meta_list, fsb, 1, EXT4_FMR_OWN_FS);
+		if (error)
+			return error;
+		fsb++;
+	}
+
+	/* Record the group descriptors. */
+	len = ext4_bg_num_gdb(sb, agno);
+	if (!len)
+		return 0;
+	error = ext4_getfsmap_fill(meta_list, fsb, len,
+				   EXT4_FMR_OWN_GDT);
+	if (error)
+		return error;
+	fsb += len;
+
+	/* Reserved GDT blocks */
+	if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) {
+		len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
+		error = ext4_getfsmap_fill(meta_list, fsb, len,
+					   EXT4_FMR_OWN_RESV_GDT);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+/* Compare two fsmap items. */
+static int ext4_getfsmap_compare(void *priv,
+				 const struct list_head *a,
+				 const struct list_head *b)
+{
+	struct ext4_fsmap *fa;
+	struct ext4_fsmap *fb;
+
+	fa = container_of(a, struct ext4_fsmap, fmr_list);
+	fb = container_of(b, struct ext4_fsmap, fmr_list);
+	if (fa->fmr_physical < fb->fmr_physical)
+		return -1;
+	else if (fa->fmr_physical > fb->fmr_physical)
+		return 1;
+	return 0;
+}
+
+/* Merge adjacent extents of fixed metadata. */
+static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list)
+{
+	struct ext4_fsmap *p;
+	struct ext4_fsmap *prev = NULL;
+	struct ext4_fsmap *tmp;
+
+	list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
+		if (!prev) {
+			prev = p;
+			continue;
+		}
+
+		if (prev->fmr_owner == p->fmr_owner &&
+		    prev->fmr_physical + prev->fmr_length == p->fmr_physical) {
+			prev->fmr_length += p->fmr_length;
+			list_del(&p->fmr_list);
+			kfree(p);
+		} else
+			prev = p;
+	}
+}
+
+/* Free a list of fixed metadata. */
+static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list)
+{
+	struct ext4_fsmap *p;
+	struct ext4_fsmap *tmp;
+
+	list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
+		list_del(&p->fmr_list);
+		kfree(p);
+	}
+}
+
+/* Find all the fixed metadata in the filesystem. */
+static int ext4_getfsmap_find_fixed_metadata(struct super_block *sb,
+					     struct list_head *meta_list)
+{
+	struct ext4_group_desc *gdp;
+	ext4_group_t agno;
+	int error;
+
+	INIT_LIST_HEAD(meta_list);
+
+	/* Collect everything. */
+	for (agno = 0; agno < EXT4_SB(sb)->s_groups_count; agno++) {
+		gdp = ext4_get_group_desc(sb, agno, NULL);
+		if (!gdp) {
+			error = -EFSCORRUPTED;
+			goto err;
+		}
+
+		/* Superblock & GDT */
+		error = ext4_getfsmap_find_sb(sb, agno, meta_list);
+		if (error)
+			goto err;
+
+		/* Block bitmap */
+		error = ext4_getfsmap_fill(meta_list,
+					   ext4_block_bitmap(sb, gdp), 1,
+					   EXT4_FMR_OWN_BLKBM);
+		if (error)
+			goto err;
+
+		/* Inode bitmap */
+		error = ext4_getfsmap_fill(meta_list,
+					   ext4_inode_bitmap(sb, gdp), 1,
+					   EXT4_FMR_OWN_INOBM);
+		if (error)
+			goto err;
+
+		/* Inodes */
+		error = ext4_getfsmap_fill(meta_list,
+					   ext4_inode_table(sb, gdp),
+					   EXT4_SB(sb)->s_itb_per_group,
+					   EXT4_FMR_OWN_INODES);
+		if (error)
+			goto err;
+	}
+
+	/* Sort the list */
+	list_sort(NULL, meta_list, ext4_getfsmap_compare);
+
+	/* Merge adjacent extents */
+	ext4_getfsmap_merge_fixed_metadata(meta_list);
+
+	return 0;
+err:
+	ext4_getfsmap_free_fixed_metadata(meta_list);
+	return error;
+}
+
+/* Execute a getfsmap query against the buddy bitmaps */
+static int ext4_getfsmap_datadev(struct super_block *sb,
+				 struct ext4_fsmap *keys,
+				 struct ext4_getfsmap_info *info)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_fsblk_t start_fsb;
+	ext4_fsblk_t end_fsb;
+	ext4_fsblk_t bofs;
+	ext4_fsblk_t eofs;
+	ext4_group_t start_ag;
+	ext4_group_t end_ag;
+	ext4_grpblk_t first_cluster;
+	ext4_grpblk_t last_cluster;
+	int error = 0;
+
+	bofs = le32_to_cpu(sbi->s_es->s_first_data_block);
+	eofs = ext4_blocks_count(sbi->s_es);
+	if (keys[0].fmr_physical >= eofs)
+		return 0;
+	else if (keys[0].fmr_physical < bofs)
+		keys[0].fmr_physical = bofs;
+	if (keys[1].fmr_physical >= eofs)
+		keys[1].fmr_physical = eofs - 1;
+	if (keys[1].fmr_physical < keys[0].fmr_physical)
+		return 0;
+	start_fsb = keys[0].fmr_physical;
+	end_fsb = keys[1].fmr_physical;
+
+	/* Determine first and last group to examine based on start and end */
+	ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster);
+	ext4_get_group_no_and_offset(sb, end_fsb, &end_ag, &last_cluster);
+
+	/*
+	 * Convert the fsmap low/high keys to bg based keys.  Initialize
+	 * low to the fsmap low key and max out the high key to the end
+	 * of the bg.
+	 */
+	info->gfi_low = keys[0];
+	info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster);
+	info->gfi_low.fmr_length = 0;
+
+	memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
+
+	/* Assemble a list of all the fixed-location metadata. */
+	error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list);
+	if (error)
+		goto err;
+
+	/* Query each bg */
+	for (info->gfi_agno = start_ag;
+	     info->gfi_agno <= end_ag;
+	     info->gfi_agno++) {
+		/*
+		 * Set the bg high key from the fsmap high key if this
+		 * is the last bg that we're querying.
+		 */
+		if (info->gfi_agno == end_ag) {
+			info->gfi_high = keys[1];
+			info->gfi_high.fmr_physical = EXT4_C2B(sbi,
+					last_cluster);
+			info->gfi_high.fmr_length = 0;
+		}
+
+		trace_ext4_fsmap_low_key(sb, info->gfi_dev, info->gfi_agno,
+				info->gfi_low.fmr_physical,
+				info->gfi_low.fmr_length,
+				info->gfi_low.fmr_owner);
+
+		trace_ext4_fsmap_high_key(sb, info->gfi_dev, info->gfi_agno,
+				info->gfi_high.fmr_physical,
+				info->gfi_high.fmr_length,
+				info->gfi_high.fmr_owner);
+
+		error = ext4_mballoc_query_range(sb, info->gfi_agno,
+				EXT4_B2C(sbi, info->gfi_low.fmr_physical),
+				EXT4_B2C(sbi, info->gfi_high.fmr_physical),
+				ext4_getfsmap_datadev_helper, info);
+		if (error)
+			goto err;
+
+		/*
+		 * Set the bg low key to the start of the bg prior to
+		 * moving on to the next bg.
+		 */
+		if (info->gfi_agno == start_ag)
+			memset(&info->gfi_low, 0, sizeof(info->gfi_low));
+	}
+
+	/* Do we have a retained free extent? */
+	if (info->gfi_lastfree.fmr_owner) {
+		error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
+		if (error)
+			goto err;
+	}
+
+	/* Report any gaps at the end of the bg */
+	info->gfi_last = true;
+	error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info);
+	if (error)
+		goto err;
+
+err:
+	ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list);
+	return error;
+}
+
+/* Do we recognize the device? */
+static bool ext4_getfsmap_is_valid_device(struct super_block *sb,
+					  struct ext4_fsmap *fm)
+{
+	if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
+	    fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev))
+		return true;
+	if (EXT4_SB(sb)->s_journal_bdev &&
+	    fm->fmr_device == new_encode_dev(EXT4_SB(sb)->s_journal_bdev->bd_dev))
+		return true;
+	return false;
+}
+
+/* Ensure that the low key is less than the high key. */
+static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key,
+				     struct ext4_fsmap *high_key)
+{
+	if (low_key->fmr_device > high_key->fmr_device)
+		return false;
+	if (low_key->fmr_device < high_key->fmr_device)
+		return true;
+
+	if (low_key->fmr_physical > high_key->fmr_physical)
+		return false;
+	if (low_key->fmr_physical < high_key->fmr_physical)
+		return true;
+
+	if (low_key->fmr_owner > high_key->fmr_owner)
+		return false;
+	if (low_key->fmr_owner < high_key->fmr_owner)
+		return true;
+
+	return false;
+}
+
+#define EXT4_GETFSMAP_DEVS	2
+/*
+ * Get filesystem's extents as described in head, and format for
+ * output.  Calls formatter to fill the user's buffer until all
+ * extents are mapped, until the passed-in head->fmh_count slots have
+ * been filled, or until the formatter short-circuits the loop, if it
+ * is tracking filled-in extents on its own.
+ *
+ * Key to Confusion
+ * ----------------
+ * There are multiple levels of keys and counters at work here:
+ * _fsmap_head.fmh_keys		-- low and high fsmap keys passed in;
+ * 				   these reflect fs-wide block addrs.
+ * dkeys			-- fmh_keys used to query each device;
+ * 				   these are fmh_keys but w/ the low key
+ * 				   bumped up by fmr_length.
+ * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this
+ *				   is how we detect gaps in the fsmap
+ *				   records and report them.
+ * _getfsmap_info.gfi_low/high	-- per-bg low/high keys computed from
+ * 				   dkeys; used to query the free space.
+ */
+int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
+		  ext4_fsmap_format_t formatter, void *arg)
+{
+	struct ext4_fsmap dkeys[2];	/* per-dev keys */
+	struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS];
+	struct ext4_getfsmap_info info = { NULL };
+	int i;
+	int error = 0;
+
+	if (head->fmh_iflags & ~FMH_IF_VALID)
+		return -EINVAL;
+	if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) ||
+	    !ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1]))
+		return -EINVAL;
+
+	head->fmh_entries = 0;
+
+	/* Set up our device handlers. */
+	memset(handlers, 0, sizeof(handlers));
+	handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev);
+	handlers[0].gfd_fn = ext4_getfsmap_datadev;
+	if (EXT4_SB(sb)->s_journal_bdev) {
+		handlers[1].gfd_dev = new_encode_dev(
+				EXT4_SB(sb)->s_journal_bdev->bd_dev);
+		handlers[1].gfd_fn = ext4_getfsmap_logdev;
+	}
+
+	sort(handlers, EXT4_GETFSMAP_DEVS, sizeof(struct ext4_getfsmap_dev),
+			ext4_getfsmap_dev_compare, NULL);
+
+	/*
+	 * To continue where we left off, we allow userspace to use the
+	 * last mapping from a previous call as the low key of the next.
+	 * This is identified by a non-zero length in the low key. We
+	 * have to increment the low key in this scenario to ensure we
+	 * don't return the same mapping again, and instead return the
+	 * very next mapping.
+	 *
+	 * Bump the physical offset as there can be no other mapping for
+	 * the same physical block range.
+	 */
+	dkeys[0] = head->fmh_keys[0];
+	dkeys[0].fmr_physical += dkeys[0].fmr_length;
+	dkeys[0].fmr_owner = 0;
+	dkeys[0].fmr_length = 0;
+	memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap));
+
+	if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1]))
+		return -EINVAL;
+
+	info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical +
+			  head->fmh_keys[0].fmr_length;
+	info.gfi_formatter = formatter;
+	info.gfi_format_arg = arg;
+	info.gfi_head = head;
+
+	/* For each device we support... */
+	for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) {
+		/* Is this device within the range the user asked for? */
+		if (!handlers[i].gfd_fn)
+			continue;
+		if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev)
+			continue;
+		if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev)
+			break;
+
+		/*
+		 * If this device number matches the high key, we have
+		 * to pass the high key to the handler to limit the
+		 * query results.  If the device number exceeds the
+		 * low key, zero out the low key so that we get
+		 * everything from the beginning.
+		 */
+		if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device)
+			dkeys[1] = head->fmh_keys[1];
+		if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device)
+			memset(&dkeys[0], 0, sizeof(struct ext4_fsmap));
+
+		info.gfi_dev = handlers[i].gfd_dev;
+		info.gfi_last = false;
+		info.gfi_agno = -1;
+		error = handlers[i].gfd_fn(sb, dkeys, &info);
+		if (error)
+			break;
+		info.gfi_next_fsblk = 0;
+	}
+
+	head->fmh_oflags = FMH_OF_DEV_T;
+	return error;
+}
diff --git a/fs/ext4/fsmap.h b/fs/ext4/fsmap.h
new file mode 100644
index 000000000..68c8001fe
--- /dev/null
+++ b/fs/ext4/fsmap.h
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#ifndef __EXT4_FSMAP_H__
+#define	__EXT4_FSMAP_H__
+
+struct fsmap;
+
+/* internal fsmap representation */
+struct ext4_fsmap {
+	struct list_head	fmr_list;
+	dev_t		fmr_device;	/* device id */
+	uint32_t	fmr_flags;	/* mapping flags */
+	uint64_t	fmr_physical;	/* device offset of segment */
+	uint64_t	fmr_owner;	/* owner id */
+	uint64_t	fmr_length;	/* length of segment, blocks */
+};
+
+struct ext4_fsmap_head {
+	uint32_t	fmh_iflags;	/* control flags */
+	uint32_t	fmh_oflags;	/* output flags */
+	unsigned int	fmh_count;	/* # of entries in array incl. input */
+	unsigned int	fmh_entries;	/* # of entries filled in (output). */
+
+	struct ext4_fsmap fmh_keys[2];	/* low and high keys */
+};
+
+void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
+		struct ext4_fsmap *src);
+void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
+		struct fsmap *src);
+
+/* fsmap to userspace formatter - copy to user & advance pointer */
+typedef int (*ext4_fsmap_format_t)(struct ext4_fsmap *, void *);
+
+int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
+		ext4_fsmap_format_t formatter, void *arg);
+
+#define EXT4_QUERY_RANGE_ABORT		1
+#define EXT4_QUERY_RANGE_CONTINUE	0
+
+/*	fmr_owner special values for FS_IOC_GETFSMAP; some share w/ XFS */
+#define EXT4_FMR_OWN_FREE	FMR_OWN_FREE      /* free space */
+#define EXT4_FMR_OWN_UNKNOWN	FMR_OWN_UNKNOWN   /* unknown owner */
+#define EXT4_FMR_OWN_FS		FMR_OWNER('X', 1) /* static fs metadata */
+#define EXT4_FMR_OWN_LOG	FMR_OWNER('X', 2) /* journalling log */
+#define EXT4_FMR_OWN_INODES	FMR_OWNER('X', 5) /* inodes */
+#define EXT4_FMR_OWN_GDT	FMR_OWNER('f', 1) /* group descriptors */
+#define EXT4_FMR_OWN_RESV_GDT	FMR_OWNER('f', 2) /* reserved gdt blocks */
+#define EXT4_FMR_OWN_BLKBM	FMR_OWNER('f', 3) /* inode bitmap */
+#define EXT4_FMR_OWN_INOBM	FMR_OWNER('f', 4) /* block bitmap */
+
+#endif /* __EXT4_FSMAP_H__ */
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
new file mode 100644
index 000000000..a42ca9584
--- /dev/null
+++ b/fs/ext4/fsync.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/fsync.c
+ *
+ *  Copyright (C) 1993  Stephen Tweedie (sct@redhat.com)
+ *  from
+ *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
+ *                      Laboratoire MASI - Institut Blaise Pascal
+ *                      Universite Pierre et Marie Curie (Paris VI)
+ *  from
+ *  linux/fs/minix/truncate.c   Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4fs fsync primitive
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ *  Removed unnecessary code duplication for little endian machines
+ *  and excessive __inline__s.
+ *        Andi Kleen, 1997
+ *
+ * Major simplications and cleanup - we only need to do the metadata, because
+ * we can depend on generic_block_fdatasync() to sync the data blocks.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
+#include <linux/blkdev.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+
+#include <trace/events/ext4.h>
+
+/*
+ * If we're not journaling and this is a just-created file, we have to
+ * sync our parent directory (if it was freshly created) since
+ * otherwise it will only be written by writeback, leaving a huge
+ * window during which a crash may lose the file.  This may apply for
+ * the parent directory's parent as well, and so on recursively, if
+ * they are also freshly created.
+ */
+static int ext4_sync_parent(struct inode *inode)
+{
+	struct dentry *dentry, *next;
+	int ret = 0;
+
+	if (!ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY))
+		return 0;
+	dentry = d_find_any_alias(inode);
+	if (!dentry)
+		return 0;
+	while (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
+		ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
+
+		next = dget_parent(dentry);
+		dput(dentry);
+		dentry = next;
+		inode = dentry->d_inode;
+
+		/*
+		 * The directory inode may have gone through rmdir by now. But
+		 * the inode itself and its blocks are still allocated (we hold
+		 * a reference to the inode via its dentry), so it didn't go
+		 * through ext4_evict_inode()) and so we are safe to flush
+		 * metadata blocks and the inode.
+		 */
+		ret = sync_mapping_buffers(inode->i_mapping);
+		if (ret)
+			break;
+		ret = sync_inode_metadata(inode, 1);
+		if (ret)
+			break;
+	}
+	dput(dentry);
+	return ret;
+}
+
+static int ext4_fsync_nojournal(struct inode *inode, bool datasync,
+				bool *needs_barrier)
+{
+	int ret, err;
+
+	ret = sync_mapping_buffers(inode->i_mapping);
+	if (!(inode->i_state & I_DIRTY_ALL))
+		return ret;
+	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
+		return ret;
+
+	err = sync_inode_metadata(inode, 1);
+	if (!ret)
+		ret = err;
+
+	if (!ret)
+		ret = ext4_sync_parent(inode);
+	if (test_opt(inode->i_sb, BARRIER))
+		*needs_barrier = true;
+
+	return ret;
+}
+
+static int ext4_fsync_journal(struct inode *inode, bool datasync,
+			     bool *needs_barrier)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+	tid_t commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
+
+	if (journal->j_flags & JBD2_BARRIER &&
+	    !jbd2_trans_will_send_data_barrier(journal, commit_tid))
+		*needs_barrier = true;
+
+	return ext4_fc_commit(journal, commit_tid);
+}
+
+/*
+ * akpm: A new design for ext4_sync_file().
+ *
+ * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
+ * There cannot be a transaction open by this task.
+ * Another task could have dirtied this inode.  Its data can be in any
+ * state in the journalling system.
+ *
+ * What we do is just kick off a commit and wait on it.  This will snapshot the
+ * inode to disk.
+ */
+int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	int ret = 0, err;
+	bool needs_barrier = false;
+	struct inode *inode = file->f_mapping->host;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+	if (unlikely(ext4_forced_shutdown(sbi)))
+		return -EIO;
+
+	J_ASSERT(ext4_journal_current_handle() == NULL);
+
+	trace_ext4_sync_file_enter(file, datasync);
+
+	if (sb_rdonly(inode->i_sb)) {
+		/* Make sure that we read updated s_mount_flags value */
+		smp_rmb();
+		if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FS_ABORTED))
+			ret = -EROFS;
+		goto out;
+	}
+
+	ret = file_write_and_wait_range(file, start, end);
+	if (ret)
+		goto out;
+
+	/*
+	 * data=writeback,ordered:
+	 *  The caller's filemap_fdatawrite()/wait will sync the data.
+	 *  Metadata is in the journal, we wait for proper transaction to
+	 *  commit here.
+	 *
+	 * data=journal:
+	 *  filemap_fdatawrite won't do anything (the buffers are clean).
+	 *  ext4_force_commit will write the file data into the journal and
+	 *  will wait on that.
+	 *  filemap_fdatawait() will encounter a ton of newly-dirtied pages
+	 *  (they were dirtied by commit).  But that's OK - the blocks are
+	 *  safe in-journal, which is all fsync() needs to ensure.
+	 */
+	if (!sbi->s_journal)
+		ret = ext4_fsync_nojournal(inode, datasync, &needs_barrier);
+	else if (ext4_should_journal_data(inode))
+		ret = ext4_force_commit(inode->i_sb);
+	else
+		ret = ext4_fsync_journal(inode, datasync, &needs_barrier);
+
+	if (needs_barrier) {
+		err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL);
+		if (!ret)
+			ret = err;
+	}
+out:
+	err = file_check_and_advance_wb_err(file);
+	if (ret == 0)
+		ret = err;
+	trace_ext4_sync_file_exit(inode, ret);
+	return ret;
+}
diff --git a/fs/ext4/hash.c b/fs/ext4/hash.c
new file mode 100644
index 000000000..a92eb79de
--- /dev/null
+++ b/fs/ext4/hash.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/hash.c
+ *
+ * Copyright (C) 2002 by Theodore Ts'o
+ */
+
+#include <linux/fs.h>
+#include <linux/unicode.h>
+#include <linux/compiler.h>
+#include <linux/bitops.h>
+#include "ext4.h"
+
+#define DELTA 0x9E3779B9
+
+static void TEA_transform(__u32 buf[4], __u32 const in[])
+{
+	__u32	sum = 0;
+	__u32	b0 = buf[0], b1 = buf[1];
+	__u32	a = in[0], b = in[1], c = in[2], d = in[3];
+	int	n = 16;
+
+	do {
+		sum += DELTA;
+		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
+		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
+	} while (--n);
+
+	buf[0] += b0;
+	buf[1] += b1;
+}
+
+/* F, G and H are basic MD4 functions: selection, majority, parity */
+#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
+#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
+#define H(x, y, z) ((x) ^ (y) ^ (z))
+
+/*
+ * The generic round function.  The application is so specific that
+ * we don't bother protecting all the arguments with parens, as is generally
+ * good macro practice, in favor of extra legibility.
+ * Rotation is separate from addition to prevent recomputation
+ */
+#define ROUND(f, a, b, c, d, x, s)	\
+	(a += f(b, c, d) + x, a = rol32(a, s))
+#define K1 0
+#define K2 013240474631UL
+#define K3 015666365641UL
+
+/*
+ * Basic cut-down MD4 transform.  Returns only 32 bits of result.
+ */
+static __u32 half_md4_transform(__u32 buf[4], __u32 const in[8])
+{
+	__u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
+
+	/* Round 1 */
+	ROUND(F, a, b, c, d, in[0] + K1,  3);
+	ROUND(F, d, a, b, c, in[1] + K1,  7);
+	ROUND(F, c, d, a, b, in[2] + K1, 11);
+	ROUND(F, b, c, d, a, in[3] + K1, 19);
+	ROUND(F, a, b, c, d, in[4] + K1,  3);
+	ROUND(F, d, a, b, c, in[5] + K1,  7);
+	ROUND(F, c, d, a, b, in[6] + K1, 11);
+	ROUND(F, b, c, d, a, in[7] + K1, 19);
+
+	/* Round 2 */
+	ROUND(G, a, b, c, d, in[1] + K2,  3);
+	ROUND(G, d, a, b, c, in[3] + K2,  5);
+	ROUND(G, c, d, a, b, in[5] + K2,  9);
+	ROUND(G, b, c, d, a, in[7] + K2, 13);
+	ROUND(G, a, b, c, d, in[0] + K2,  3);
+	ROUND(G, d, a, b, c, in[2] + K2,  5);
+	ROUND(G, c, d, a, b, in[4] + K2,  9);
+	ROUND(G, b, c, d, a, in[6] + K2, 13);
+
+	/* Round 3 */
+	ROUND(H, a, b, c, d, in[3] + K3,  3);
+	ROUND(H, d, a, b, c, in[7] + K3,  9);
+	ROUND(H, c, d, a, b, in[2] + K3, 11);
+	ROUND(H, b, c, d, a, in[6] + K3, 15);
+	ROUND(H, a, b, c, d, in[1] + K3,  3);
+	ROUND(H, d, a, b, c, in[5] + K3,  9);
+	ROUND(H, c, d, a, b, in[0] + K3, 11);
+	ROUND(H, b, c, d, a, in[4] + K3, 15);
+
+	buf[0] += a;
+	buf[1] += b;
+	buf[2] += c;
+	buf[3] += d;
+
+	return buf[1]; /* "most hashed" word */
+}
+#undef ROUND
+#undef K1
+#undef K2
+#undef K3
+#undef F
+#undef G
+#undef H
+
+/* The old legacy hash */
+static __u32 dx_hack_hash_unsigned(const char *name, int len)
+{
+	__u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+	const unsigned char *ucp = (const unsigned char *) name;
+
+	while (len--) {
+		hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
+
+		if (hash & 0x80000000)
+			hash -= 0x7fffffff;
+		hash1 = hash0;
+		hash0 = hash;
+	}
+	return hash0 << 1;
+}
+
+static __u32 dx_hack_hash_signed(const char *name, int len)
+{
+	__u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+	const signed char *scp = (const signed char *) name;
+
+	while (len--) {
+		hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
+
+		if (hash & 0x80000000)
+			hash -= 0x7fffffff;
+		hash1 = hash0;
+		hash0 = hash;
+	}
+	return hash0 << 1;
+}
+
+static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
+{
+	__u32	pad, val;
+	int	i;
+	const signed char *scp = (const signed char *) msg;
+
+	pad = (__u32)len | ((__u32)len << 8);
+	pad |= pad << 16;
+
+	val = pad;
+	if (len > num*4)
+		len = num * 4;
+	for (i = 0; i < len; i++) {
+		val = ((int) scp[i]) + (val << 8);
+		if ((i % 4) == 3) {
+			*buf++ = val;
+			val = pad;
+			num--;
+		}
+	}
+	if (--num >= 0)
+		*buf++ = val;
+	while (--num >= 0)
+		*buf++ = pad;
+}
+
+static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
+{
+	__u32	pad, val;
+	int	i;
+	const unsigned char *ucp = (const unsigned char *) msg;
+
+	pad = (__u32)len | ((__u32)len << 8);
+	pad |= pad << 16;
+
+	val = pad;
+	if (len > num*4)
+		len = num * 4;
+	for (i = 0; i < len; i++) {
+		val = ((int) ucp[i]) + (val << 8);
+		if ((i % 4) == 3) {
+			*buf++ = val;
+			val = pad;
+			num--;
+		}
+	}
+	if (--num >= 0)
+		*buf++ = val;
+	while (--num >= 0)
+		*buf++ = pad;
+}
+
+/*
+ * Returns the hash of a filename.  If len is 0 and name is NULL, then
+ * this function can be used to test whether or not a hash version is
+ * supported.
+ *
+ * The seed is an 4 longword (32 bits) "secret" which can be used to
+ * uniquify a hash.  If the seed is all zero's, then some default seed
+ * may be used.
+ *
+ * A particular hash version specifies whether or not the seed is
+ * represented, and whether or not the returned hash is 32 bits or 64
+ * bits.  32 bit hashes will return 0 for the minor hash.
+ */
+static int __ext4fs_dirhash(const char *name, int len,
+			    struct dx_hash_info *hinfo)
+{
+	__u32	hash;
+	__u32	minor_hash = 0;
+	const char	*p;
+	int		i;
+	__u32		in[8], buf[4];
+	void		(*str2hashbuf)(const char *, int, __u32 *, int) =
+				str2hashbuf_signed;
+
+	/* Initialize the default seed for the hash checksum functions */
+	buf[0] = 0x67452301;
+	buf[1] = 0xefcdab89;
+	buf[2] = 0x98badcfe;
+	buf[3] = 0x10325476;
+
+	/* Check to see if the seed is all zero's */
+	if (hinfo->seed) {
+		for (i = 0; i < 4; i++) {
+			if (hinfo->seed[i]) {
+				memcpy(buf, hinfo->seed, sizeof(buf));
+				break;
+			}
+		}
+	}
+
+	switch (hinfo->hash_version) {
+	case DX_HASH_LEGACY_UNSIGNED:
+		hash = dx_hack_hash_unsigned(name, len);
+		break;
+	case DX_HASH_LEGACY:
+		hash = dx_hack_hash_signed(name, len);
+		break;
+	case DX_HASH_HALF_MD4_UNSIGNED:
+		str2hashbuf = str2hashbuf_unsigned;
+		fallthrough;
+	case DX_HASH_HALF_MD4:
+		p = name;
+		while (len > 0) {
+			(*str2hashbuf)(p, len, in, 8);
+			half_md4_transform(buf, in);
+			len -= 32;
+			p += 32;
+		}
+		minor_hash = buf[2];
+		hash = buf[1];
+		break;
+	case DX_HASH_TEA_UNSIGNED:
+		str2hashbuf = str2hashbuf_unsigned;
+		fallthrough;
+	case DX_HASH_TEA:
+		p = name;
+		while (len > 0) {
+			(*str2hashbuf)(p, len, in, 4);
+			TEA_transform(buf, in);
+			len -= 16;
+			p += 16;
+		}
+		hash = buf[0];
+		minor_hash = buf[1];
+		break;
+	default:
+		hinfo->hash = 0;
+		return -1;
+	}
+	hash = hash & ~1;
+	if (hash == (EXT4_HTREE_EOF_32BIT << 1))
+		hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
+	hinfo->hash = hash;
+	hinfo->minor_hash = minor_hash;
+	return 0;
+}
+
+int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
+		   struct dx_hash_info *hinfo)
+{
+#ifdef CONFIG_UNICODE
+	const struct unicode_map *um = dir->i_sb->s_encoding;
+	int r, dlen;
+	unsigned char *buff;
+	struct qstr qstr = {.name = name, .len = len };
+
+	if (len && IS_CASEFOLDED(dir) && um) {
+		buff = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL);
+		if (!buff)
+			return -ENOMEM;
+
+		dlen = utf8_casefold(um, &qstr, buff, PATH_MAX);
+		if (dlen < 0) {
+			kfree(buff);
+			goto opaque_seq;
+		}
+
+		r = __ext4fs_dirhash(buff, dlen, hinfo);
+
+		kfree(buff);
+		return r;
+	}
+opaque_seq:
+#endif
+	return __ext4fs_dirhash(name, len, hinfo);
+}
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
new file mode 100644
index 000000000..d178543ca
--- /dev/null
+++ b/fs/ext4/ialloc.c
@@ -0,0 +1,1626 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/ialloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  BSD ufs-inspired inode and directory allocation by
+ *  Stephen Tweedie (sct@redhat.com), 1993
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/random.h>
+#include <linux/bitops.h>
+#include <linux/blkdev.h>
+#include <linux/cred.h>
+
+#include <asm/byteorder.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+
+#include <trace/events/ext4.h>
+
+/*
+ * ialloc.c contains the inodes allocation and deallocation routines
+ */
+
+/*
+ * The free inodes are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.
+ */
+
+/*
+ * To avoid calling the atomic setbit hundreds or thousands of times, we only
+ * need to use it within a single byte (to ensure we get endianness right).
+ * We can use memset for the rest of the bitmap as there are no other users.
+ */
+void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
+{
+	int i;
+
+	if (start_bit >= end_bit)
+		return;
+
+	ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
+	for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
+		ext4_set_bit(i, bitmap);
+	if (i < end_bit)
+		memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
+}
+
+void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
+{
+	if (uptodate) {
+		set_buffer_uptodate(bh);
+		set_bitmap_uptodate(bh);
+	}
+	unlock_buffer(bh);
+	put_bh(bh);
+}
+
+static int ext4_validate_inode_bitmap(struct super_block *sb,
+				      struct ext4_group_desc *desc,
+				      ext4_group_t block_group,
+				      struct buffer_head *bh)
+{
+	ext4_fsblk_t	blk;
+	struct ext4_group_info *grp;
+
+	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	grp = ext4_get_group_info(sb, block_group);
+
+	if (buffer_verified(bh))
+		return 0;
+	if (!grp || EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
+		return -EFSCORRUPTED;
+
+	ext4_lock_group(sb, block_group);
+	if (buffer_verified(bh))
+		goto verified;
+	blk = ext4_inode_bitmap(sb, desc);
+	if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
+					   EXT4_INODES_PER_GROUP(sb) / 8) ||
+	    ext4_simulate_fail(sb, EXT4_SIM_IBITMAP_CRC)) {
+		ext4_unlock_group(sb, block_group);
+		ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
+			   "inode_bitmap = %llu", block_group, blk);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
+		return -EFSBADCRC;
+	}
+	set_buffer_verified(bh);
+verified:
+	ext4_unlock_group(sb, block_group);
+	return 0;
+}
+
+/*
+ * Read the inode allocation bitmap for a given block_group, reading
+ * into the specified slot in the superblock's bitmap cache.
+ *
+ * Return buffer_head of bitmap on success, or an ERR_PTR on error.
+ */
+static struct buffer_head *
+ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
+{
+	struct ext4_group_desc *desc;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct buffer_head *bh = NULL;
+	ext4_fsblk_t bitmap_blk;
+	int err;
+
+	desc = ext4_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		return ERR_PTR(-EFSCORRUPTED);
+
+	bitmap_blk = ext4_inode_bitmap(sb, desc);
+	if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
+	    (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
+		ext4_error(sb, "Invalid inode bitmap blk %llu in "
+			   "block_group %u", bitmap_blk, block_group);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+	bh = sb_getblk(sb, bitmap_blk);
+	if (unlikely(!bh)) {
+		ext4_warning(sb, "Cannot read inode bitmap - "
+			     "block_group = %u, inode_bitmap = %llu",
+			     block_group, bitmap_blk);
+		return ERR_PTR(-ENOMEM);
+	}
+	if (bitmap_uptodate(bh))
+		goto verify;
+
+	lock_buffer(bh);
+	if (bitmap_uptodate(bh)) {
+		unlock_buffer(bh);
+		goto verify;
+	}
+
+	ext4_lock_group(sb, block_group);
+	if (ext4_has_group_desc_csum(sb) &&
+	    (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
+		if (block_group == 0) {
+			ext4_unlock_group(sb, block_group);
+			unlock_buffer(bh);
+			ext4_error(sb, "Inode bitmap for bg 0 marked "
+				   "uninitialized");
+			err = -EFSCORRUPTED;
+			goto out;
+		}
+		memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
+		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
+				     sb->s_blocksize * 8, bh->b_data);
+		set_bitmap_uptodate(bh);
+		set_buffer_uptodate(bh);
+		set_buffer_verified(bh);
+		ext4_unlock_group(sb, block_group);
+		unlock_buffer(bh);
+		return bh;
+	}
+	ext4_unlock_group(sb, block_group);
+
+	if (buffer_uptodate(bh)) {
+		/*
+		 * if not uninit if bh is uptodate,
+		 * bitmap is also uptodate
+		 */
+		set_bitmap_uptodate(bh);
+		unlock_buffer(bh);
+		goto verify;
+	}
+	/*
+	 * submit the buffer_head for reading
+	 */
+	trace_ext4_load_inode_bitmap(sb, block_group);
+	ext4_read_bh(bh, REQ_META | REQ_PRIO, ext4_end_bitmap_read);
+	ext4_simulate_fail_bh(sb, bh, EXT4_SIM_IBITMAP_EIO);
+	if (!buffer_uptodate(bh)) {
+		put_bh(bh);
+		ext4_error_err(sb, EIO, "Cannot read inode bitmap - "
+			       "block_group = %u, inode_bitmap = %llu",
+			       block_group, bitmap_blk);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+				EXT4_GROUP_INFO_IBITMAP_CORRUPT);
+		return ERR_PTR(-EIO);
+	}
+
+verify:
+	err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
+	if (err)
+		goto out;
+	return bh;
+out:
+	put_bh(bh);
+	return ERR_PTR(err);
+}
+
+/*
+ * NOTE! When we get the inode, we're the only people
+ * that have access to it, and as such there are no
+ * race conditions we have to worry about. The inode
+ * is not on the hash-lists, and it cannot be reached
+ * through the filesystem because the directory entry
+ * has been deleted earlier.
+ *
+ * HOWEVER: we must make sure that we get no aliases,
+ * which means that we have to call "clear_inode()"
+ * _before_ we mark the inode not in use in the inode
+ * bitmaps. Otherwise a newly created file might use
+ * the same inode number (not actually the same pointer
+ * though), and then we'd have two inodes sharing the
+ * same inode number and space on the harddisk.
+ */
+void ext4_free_inode(handle_t *handle, struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	int is_directory;
+	unsigned long ino;
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *bh2;
+	ext4_group_t block_group;
+	unsigned long bit;
+	struct ext4_group_desc *gdp;
+	struct ext4_super_block *es;
+	struct ext4_sb_info *sbi;
+	int fatal = 0, err, count, cleared;
+	struct ext4_group_info *grp;
+
+	if (!sb) {
+		printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
+		       "nonexistent device\n", __func__, __LINE__);
+		return;
+	}
+	if (atomic_read(&inode->i_count) > 1) {
+		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
+			 __func__, __LINE__, inode->i_ino,
+			 atomic_read(&inode->i_count));
+		return;
+	}
+	if (inode->i_nlink) {
+		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
+			 __func__, __LINE__, inode->i_ino, inode->i_nlink);
+		return;
+	}
+	sbi = EXT4_SB(sb);
+
+	ino = inode->i_ino;
+	ext4_debug("freeing inode %lu\n", ino);
+	trace_ext4_free_inode(inode);
+
+	dquot_initialize(inode);
+	dquot_free_inode(inode);
+
+	is_directory = S_ISDIR(inode->i_mode);
+
+	/* Do this BEFORE marking the inode not in use or returning an error */
+	ext4_clear_inode(inode);
+
+	es = sbi->s_es;
+	if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
+		ext4_error(sb, "reserved or nonexistent inode %lu", ino);
+		goto error_return;
+	}
+	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
+	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
+	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
+	/* Don't bother if the inode bitmap is corrupt. */
+	if (IS_ERR(bitmap_bh)) {
+		fatal = PTR_ERR(bitmap_bh);
+		bitmap_bh = NULL;
+		goto error_return;
+	}
+	if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+		grp = ext4_get_group_info(sb, block_group);
+		if (!grp || unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
+			fatal = -EFSCORRUPTED;
+			goto error_return;
+		}
+	}
+
+	BUFFER_TRACE(bitmap_bh, "get_write_access");
+	fatal = ext4_journal_get_write_access(handle, bitmap_bh);
+	if (fatal)
+		goto error_return;
+
+	fatal = -ESRCH;
+	gdp = ext4_get_group_desc(sb, block_group, &bh2);
+	if (gdp) {
+		BUFFER_TRACE(bh2, "get_write_access");
+		fatal = ext4_journal_get_write_access(handle, bh2);
+	}
+	ext4_lock_group(sb, block_group);
+	cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
+	if (fatal || !cleared) {
+		ext4_unlock_group(sb, block_group);
+		goto out;
+	}
+
+	count = ext4_free_inodes_count(sb, gdp) + 1;
+	ext4_free_inodes_set(sb, gdp, count);
+	if (is_directory) {
+		count = ext4_used_dirs_count(sb, gdp) - 1;
+		ext4_used_dirs_set(sb, gdp, count);
+		if (percpu_counter_initialized(&sbi->s_dirs_counter))
+			percpu_counter_dec(&sbi->s_dirs_counter);
+	}
+	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
+				   EXT4_INODES_PER_GROUP(sb) / 8);
+	ext4_group_desc_csum_set(sb, block_group, gdp);
+	ext4_unlock_group(sb, block_group);
+
+	if (percpu_counter_initialized(&sbi->s_freeinodes_counter))
+		percpu_counter_inc(&sbi->s_freeinodes_counter);
+	if (sbi->s_log_groups_per_flex) {
+		struct flex_groups *fg;
+
+		fg = sbi_array_rcu_deref(sbi, s_flex_groups,
+					 ext4_flex_group(sbi, block_group));
+		atomic_inc(&fg->free_inodes);
+		if (is_directory)
+			atomic_dec(&fg->used_dirs);
+	}
+	BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
+	fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
+out:
+	if (cleared) {
+		BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
+		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+		if (!fatal)
+			fatal = err;
+	} else {
+		ext4_error(sb, "bit already cleared for inode %lu", ino);
+		ext4_mark_group_bitmap_corrupted(sb, block_group,
+					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
+	}
+
+error_return:
+	brelse(bitmap_bh);
+	ext4_std_error(sb, fatal);
+}
+
+struct orlov_stats {
+	__u64 free_clusters;
+	__u32 free_inodes;
+	__u32 used_dirs;
+};
+
+/*
+ * Helper function for Orlov's allocator; returns critical information
+ * for a particular block group or flex_bg.  If flex_size is 1, then g
+ * is a block group number; otherwise it is flex_bg number.
+ */
+static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
+			    int flex_size, struct orlov_stats *stats)
+{
+	struct ext4_group_desc *desc;
+
+	if (flex_size > 1) {
+		struct flex_groups *fg = sbi_array_rcu_deref(EXT4_SB(sb),
+							     s_flex_groups, g);
+		stats->free_inodes = atomic_read(&fg->free_inodes);
+		stats->free_clusters = atomic64_read(&fg->free_clusters);
+		stats->used_dirs = atomic_read(&fg->used_dirs);
+		return;
+	}
+
+	desc = ext4_get_group_desc(sb, g, NULL);
+	if (desc) {
+		stats->free_inodes = ext4_free_inodes_count(sb, desc);
+		stats->free_clusters = ext4_free_group_clusters(sb, desc);
+		stats->used_dirs = ext4_used_dirs_count(sb, desc);
+	} else {
+		stats->free_inodes = 0;
+		stats->free_clusters = 0;
+		stats->used_dirs = 0;
+	}
+}
+
+/*
+ * Orlov's allocator for directories.
+ *
+ * We always try to spread first-level directories.
+ *
+ * If there are blockgroups with both free inodes and free clusters counts
+ * not worse than average we return one with smallest directory count.
+ * Otherwise we simply return a random group.
+ *
+ * For the rest rules look so:
+ *
+ * It's OK to put directory into a group unless
+ * it has too many directories already (max_dirs) or
+ * it has too few free inodes left (min_inodes) or
+ * it has too few free clusters left (min_clusters) or
+ * Parent's group is preferred, if it doesn't satisfy these
+ * conditions we search cyclically through the rest. If none
+ * of the groups look good we just look for a group with more
+ * free inodes than average (starting at parent's group).
+ */
+
+static int find_group_orlov(struct super_block *sb, struct inode *parent,
+			    ext4_group_t *group, umode_t mode,
+			    const struct qstr *qstr)
+{
+	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_group_t real_ngroups = ext4_get_groups_count(sb);
+	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
+	unsigned int freei, avefreei, grp_free;
+	ext4_fsblk_t freec, avefreec;
+	unsigned int ndirs;
+	int max_dirs, min_inodes;
+	ext4_grpblk_t min_clusters;
+	ext4_group_t i, grp, g, ngroups;
+	struct ext4_group_desc *desc;
+	struct orlov_stats stats;
+	int flex_size = ext4_flex_bg_size(sbi);
+	struct dx_hash_info hinfo;
+
+	ngroups = real_ngroups;
+	if (flex_size > 1) {
+		ngroups = (real_ngroups + flex_size - 1) >>
+			sbi->s_log_groups_per_flex;
+		parent_group >>= sbi->s_log_groups_per_flex;
+	}
+
+	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
+	avefreei = freei / ngroups;
+	freec = percpu_counter_read_positive(&sbi->s_freeclusters_counter);
+	avefreec = freec;
+	do_div(avefreec, ngroups);
+	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
+
+	if (S_ISDIR(mode) &&
+	    ((parent == d_inode(sb->s_root)) ||
+	     (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
+		int best_ndir = inodes_per_group;
+		int ret = -1;
+
+		if (qstr) {
+			hinfo.hash_version = DX_HASH_HALF_MD4;
+			hinfo.seed = sbi->s_hash_seed;
+			ext4fs_dirhash(parent, qstr->name, qstr->len, &hinfo);
+			grp = hinfo.hash;
+		} else
+			grp = prandom_u32();
+		parent_group = (unsigned)grp % ngroups;
+		for (i = 0; i < ngroups; i++) {
+			g = (parent_group + i) % ngroups;
+			get_orlov_stats(sb, g, flex_size, &stats);
+			if (!stats.free_inodes)
+				continue;
+			if (stats.used_dirs >= best_ndir)
+				continue;
+			if (stats.free_inodes < avefreei)
+				continue;
+			if (stats.free_clusters < avefreec)
+				continue;
+			grp = g;
+			ret = 0;
+			best_ndir = stats.used_dirs;
+		}
+		if (ret)
+			goto fallback;
+	found_flex_bg:
+		if (flex_size == 1) {
+			*group = grp;
+			return 0;
+		}
+
+		/*
+		 * We pack inodes at the beginning of the flexgroup's
+		 * inode tables.  Block allocation decisions will do
+		 * something similar, although regular files will
+		 * start at 2nd block group of the flexgroup.  See
+		 * ext4_ext_find_goal() and ext4_find_near().
+		 */
+		grp *= flex_size;
+		for (i = 0; i < flex_size; i++) {
+			if (grp+i >= real_ngroups)
+				break;
+			desc = ext4_get_group_desc(sb, grp+i, NULL);
+			if (desc && ext4_free_inodes_count(sb, desc)) {
+				*group = grp+i;
+				return 0;
+			}
+		}
+		goto fallback;
+	}
+
+	max_dirs = ndirs / ngroups + inodes_per_group*flex_size / 16;
+	min_inodes = avefreei - inodes_per_group*flex_size / 4;
+	if (min_inodes < 1)
+		min_inodes = 1;
+	min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
+
+	/*
+	 * Start looking in the flex group where we last allocated an
+	 * inode for this parent directory
+	 */
+	if (EXT4_I(parent)->i_last_alloc_group != ~0) {
+		parent_group = EXT4_I(parent)->i_last_alloc_group;
+		if (flex_size > 1)
+			parent_group >>= sbi->s_log_groups_per_flex;
+	}
+
+	for (i = 0; i < ngroups; i++) {
+		grp = (parent_group + i) % ngroups;
+		get_orlov_stats(sb, grp, flex_size, &stats);
+		if (stats.used_dirs >= max_dirs)
+			continue;
+		if (stats.free_inodes < min_inodes)
+			continue;
+		if (stats.free_clusters < min_clusters)
+			continue;
+		goto found_flex_bg;
+	}
+
+fallback:
+	ngroups = real_ngroups;
+	avefreei = freei / ngroups;
+fallback_retry:
+	parent_group = EXT4_I(parent)->i_block_group;
+	for (i = 0; i < ngroups; i++) {
+		grp = (parent_group + i) % ngroups;
+		desc = ext4_get_group_desc(sb, grp, NULL);
+		if (desc) {
+			grp_free = ext4_free_inodes_count(sb, desc);
+			if (grp_free && grp_free >= avefreei) {
+				*group = grp;
+				return 0;
+			}
+		}
+	}
+
+	if (avefreei) {
+		/*
+		 * The free-inodes counter is approximate, and for really small
+		 * filesystems the above test can fail to find any blockgroups
+		 */
+		avefreei = 0;
+		goto fallback_retry;
+	}
+
+	return -1;
+}
+
+static int find_group_other(struct super_block *sb, struct inode *parent,
+			    ext4_group_t *group, umode_t mode)
+{
+	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
+	ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
+	struct ext4_group_desc *desc;
+	int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
+
+	/*
+	 * Try to place the inode is the same flex group as its
+	 * parent.  If we can't find space, use the Orlov algorithm to
+	 * find another flex group, and store that information in the
+	 * parent directory's inode information so that use that flex
+	 * group for future allocations.
+	 */
+	if (flex_size > 1) {
+		int retry = 0;
+
+	try_again:
+		parent_group &= ~(flex_size-1);
+		last = parent_group + flex_size;
+		if (last > ngroups)
+			last = ngroups;
+		for  (i = parent_group; i < last; i++) {
+			desc = ext4_get_group_desc(sb, i, NULL);
+			if (desc && ext4_free_inodes_count(sb, desc)) {
+				*group = i;
+				return 0;
+			}
+		}
+		if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
+			retry = 1;
+			parent_group = EXT4_I(parent)->i_last_alloc_group;
+			goto try_again;
+		}
+		/*
+		 * If this didn't work, use the Orlov search algorithm
+		 * to find a new flex group; we pass in the mode to
+		 * avoid the topdir algorithms.
+		 */
+		*group = parent_group + flex_size;
+		if (*group > ngroups)
+			*group = 0;
+		return find_group_orlov(sb, parent, group, mode, NULL);
+	}
+
+	/*
+	 * Try to place the inode in its parent directory
+	 */
+	*group = parent_group;
+	desc = ext4_get_group_desc(sb, *group, NULL);
+	if (desc && ext4_free_inodes_count(sb, desc) &&
+	    ext4_free_group_clusters(sb, desc))
+		return 0;
+
+	/*
+	 * We're going to place this inode in a different blockgroup from its
+	 * parent.  We want to cause files in a common directory to all land in
+	 * the same blockgroup.  But we want files which are in a different
+	 * directory which shares a blockgroup with our parent to land in a
+	 * different blockgroup.
+	 *
+	 * So add our directory's i_ino into the starting point for the hash.
+	 */
+	*group = (*group + parent->i_ino) % ngroups;
+
+	/*
+	 * Use a quadratic hash to find a group with a free inode and some free
+	 * blocks.
+	 */
+	for (i = 1; i < ngroups; i <<= 1) {
+		*group += i;
+		if (*group >= ngroups)
+			*group -= ngroups;
+		desc = ext4_get_group_desc(sb, *group, NULL);
+		if (desc && ext4_free_inodes_count(sb, desc) &&
+		    ext4_free_group_clusters(sb, desc))
+			return 0;
+	}
+
+	/*
+	 * That failed: try linear search for a free inode, even if that group
+	 * has no free blocks.
+	 */
+	*group = parent_group;
+	for (i = 0; i < ngroups; i++) {
+		if (++*group >= ngroups)
+			*group = 0;
+		desc = ext4_get_group_desc(sb, *group, NULL);
+		if (desc && ext4_free_inodes_count(sb, desc))
+			return 0;
+	}
+
+	return -1;
+}
+
+/*
+ * In no journal mode, if an inode has recently been deleted, we want
+ * to avoid reusing it until we're reasonably sure the inode table
+ * block has been written back to disk.  (Yes, these values are
+ * somewhat arbitrary...)
+ */
+#define RECENTCY_MIN	60
+#define RECENTCY_DIRTY	300
+
+static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
+{
+	struct ext4_group_desc	*gdp;
+	struct ext4_inode	*raw_inode;
+	struct buffer_head	*bh;
+	int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
+	int offset, ret = 0;
+	int recentcy = RECENTCY_MIN;
+	u32 dtime, now;
+
+	gdp = ext4_get_group_desc(sb, group, NULL);
+	if (unlikely(!gdp))
+		return 0;
+
+	bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
+		       (ino / inodes_per_block));
+	if (!bh || !buffer_uptodate(bh))
+		/*
+		 * If the block is not in the buffer cache, then it
+		 * must have been written out.
+		 */
+		goto out;
+
+	offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
+	raw_inode = (struct ext4_inode *) (bh->b_data + offset);
+
+	/* i_dtime is only 32 bits on disk, but we only care about relative
+	 * times in the range of a few minutes (i.e. long enough to sync a
+	 * recently-deleted inode to disk), so using the low 32 bits of the
+	 * clock (a 68 year range) is enough, see time_before32() */
+	dtime = le32_to_cpu(raw_inode->i_dtime);
+	now = ktime_get_real_seconds();
+	if (buffer_dirty(bh))
+		recentcy += RECENTCY_DIRTY;
+
+	if (dtime && time_before32(dtime, now) &&
+	    time_before32(now, dtime + recentcy))
+		ret = 1;
+out:
+	brelse(bh);
+	return ret;
+}
+
+static int find_inode_bit(struct super_block *sb, ext4_group_t group,
+			  struct buffer_head *bitmap, unsigned long *ino)
+{
+	bool check_recently_deleted = EXT4_SB(sb)->s_journal == NULL;
+	unsigned long recently_deleted_ino = EXT4_INODES_PER_GROUP(sb);
+
+next:
+	*ino = ext4_find_next_zero_bit((unsigned long *)
+				       bitmap->b_data,
+				       EXT4_INODES_PER_GROUP(sb), *ino);
+	if (*ino >= EXT4_INODES_PER_GROUP(sb))
+		goto not_found;
+
+	if (check_recently_deleted && recently_deleted(sb, group, *ino)) {
+		recently_deleted_ino = *ino;
+		*ino = *ino + 1;
+		if (*ino < EXT4_INODES_PER_GROUP(sb))
+			goto next;
+		goto not_found;
+	}
+	return 1;
+not_found:
+	if (recently_deleted_ino >= EXT4_INODES_PER_GROUP(sb))
+		return 0;
+	/*
+	 * Not reusing recently deleted inodes is mostly a preference. We don't
+	 * want to report ENOSPC or skew allocation patterns because of that.
+	 * So return even recently deleted inode if we could find better in the
+	 * given range.
+	 */
+	*ino = recently_deleted_ino;
+	return 1;
+}
+
+int ext4_mark_inode_used(struct super_block *sb, int ino)
+{
+	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
+	struct buffer_head *inode_bitmap_bh = NULL, *group_desc_bh = NULL;
+	struct ext4_group_desc *gdp;
+	ext4_group_t group;
+	int bit;
+	int err = -EFSCORRUPTED;
+
+	if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
+		goto out;
+
+	group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
+	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
+	inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
+	if (IS_ERR(inode_bitmap_bh))
+		return PTR_ERR(inode_bitmap_bh);
+
+	if (ext4_test_bit(bit, inode_bitmap_bh->b_data)) {
+		err = 0;
+		goto out;
+	}
+
+	gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
+	if (!gdp || !group_desc_bh) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	ext4_set_bit(bit, inode_bitmap_bh->b_data);
+
+	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_metadata(NULL, NULL, inode_bitmap_bh);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto out;
+	}
+	err = sync_dirty_buffer(inode_bitmap_bh);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto out;
+	}
+
+	/* We may have to initialize the block bitmap if it isn't already */
+	if (ext4_has_group_desc_csum(sb) &&
+	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+		struct buffer_head *block_bitmap_bh;
+
+		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (IS_ERR(block_bitmap_bh)) {
+			err = PTR_ERR(block_bitmap_bh);
+			goto out;
+		}
+
+		BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
+		err = ext4_handle_dirty_metadata(NULL, NULL, block_bitmap_bh);
+		sync_dirty_buffer(block_bitmap_bh);
+
+		/* recheck and clear flag under lock if we still need to */
+		ext4_lock_group(sb, group);
+		if (ext4_has_group_desc_csum(sb) &&
+		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+			ext4_free_group_clusters_set(sb, gdp,
+				ext4_free_clusters_after_init(sb, group, gdp));
+			ext4_block_bitmap_csum_set(sb, group, gdp,
+						   block_bitmap_bh);
+			ext4_group_desc_csum_set(sb, group, gdp);
+		}
+		ext4_unlock_group(sb, group);
+		brelse(block_bitmap_bh);
+
+		if (err) {
+			ext4_std_error(sb, err);
+			goto out;
+		}
+	}
+
+	/* Update the relevant bg descriptor fields */
+	if (ext4_has_group_desc_csum(sb)) {
+		int free;
+
+		ext4_lock_group(sb, group); /* while we modify the bg desc */
+		free = EXT4_INODES_PER_GROUP(sb) -
+			ext4_itable_unused_count(sb, gdp);
+		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
+			free = 0;
+		}
+
+		/*
+		 * Check the relative inode number against the last used
+		 * relative inode number in this group. if it is greater
+		 * we need to update the bg_itable_unused count
+		 */
+		if (bit >= free)
+			ext4_itable_unused_set(sb, gdp,
+					(EXT4_INODES_PER_GROUP(sb) - bit - 1));
+	} else {
+		ext4_lock_group(sb, group);
+	}
+
+	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
+	if (ext4_has_group_desc_csum(sb)) {
+		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
+					   EXT4_INODES_PER_GROUP(sb) / 8);
+		ext4_group_desc_csum_set(sb, group, gdp);
+	}
+
+	ext4_unlock_group(sb, group);
+	err = ext4_handle_dirty_metadata(NULL, NULL, group_desc_bh);
+	sync_dirty_buffer(group_desc_bh);
+out:
+	return err;
+}
+
+static int ext4_xattr_credits_for_new_inode(struct inode *dir, mode_t mode,
+					    bool encrypt)
+{
+	struct super_block *sb = dir->i_sb;
+	int nblocks = 0;
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+	struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
+
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+	if (p) {
+		int acl_size = p->a_count * sizeof(ext4_acl_entry);
+
+		nblocks += (S_ISDIR(mode) ? 2 : 1) *
+			__ext4_xattr_set_credits(sb, NULL /* inode */,
+						 NULL /* block_bh */, acl_size,
+						 true /* is_create */);
+		posix_acl_release(p);
+	}
+#endif
+
+#ifdef CONFIG_SECURITY
+	{
+		int num_security_xattrs = 1;
+
+#ifdef CONFIG_INTEGRITY
+		num_security_xattrs++;
+#endif
+		/*
+		 * We assume that security xattrs are never more than 1k.
+		 * In practice they are under 128 bytes.
+		 */
+		nblocks += num_security_xattrs *
+			__ext4_xattr_set_credits(sb, NULL /* inode */,
+						 NULL /* block_bh */, 1024,
+						 true /* is_create */);
+	}
+#endif
+	if (encrypt)
+		nblocks += __ext4_xattr_set_credits(sb,
+						    NULL /* inode */,
+						    NULL /* block_bh */,
+						    FSCRYPT_SET_CONTEXT_MAX_SIZE,
+						    true /* is_create */);
+	return nblocks;
+}
+
+/*
+ * There are two policies for allocating an inode.  If the new inode is
+ * a directory, then a forward search is made for a block group with both
+ * free space and a low directory-to-inode ratio; if that fails, then of
+ * the groups with above-average free space, that group with the fewest
+ * directories already is chosen.
+ *
+ * For other inodes, search forward from the parent directory's block
+ * group to find a free inode.
+ */
+struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
+			       umode_t mode, const struct qstr *qstr,
+			       __u32 goal, uid_t *owner, __u32 i_flags,
+			       int handle_type, unsigned int line_no,
+			       int nblocks)
+{
+	struct super_block *sb;
+	struct buffer_head *inode_bitmap_bh = NULL;
+	struct buffer_head *group_desc_bh;
+	ext4_group_t ngroups, group = 0;
+	unsigned long ino = 0;
+	struct inode *inode;
+	struct ext4_group_desc *gdp = NULL;
+	struct ext4_inode_info *ei;
+	struct ext4_sb_info *sbi;
+	int ret2, err;
+	struct inode *ret;
+	ext4_group_t i;
+	ext4_group_t flex_group;
+	struct ext4_group_info *grp = NULL;
+	bool encrypt = false;
+
+	/* Cannot create files in a deleted directory */
+	if (!dir || !dir->i_nlink)
+		return ERR_PTR(-EPERM);
+
+	sb = dir->i_sb;
+	sbi = EXT4_SB(sb);
+
+	if (unlikely(ext4_forced_shutdown(sbi)))
+		return ERR_PTR(-EIO);
+
+	ngroups = ext4_get_groups_count(sb);
+	trace_ext4_request_inode(dir, mode);
+	inode = new_inode(sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	ei = EXT4_I(inode);
+
+	/*
+	 * Initialize owners and quota early so that we don't have to account
+	 * for quota initialization worst case in standard inode creating
+	 * transaction
+	 */
+	if (owner) {
+		inode->i_mode = mode;
+		i_uid_write(inode, owner[0]);
+		i_gid_write(inode, owner[1]);
+	} else if (test_opt(sb, GRPID)) {
+		inode->i_mode = mode;
+		inode->i_uid = current_fsuid();
+		inode->i_gid = dir->i_gid;
+	} else
+		inode_init_owner(inode, dir, mode);
+
+	if (ext4_has_feature_project(sb) &&
+	    ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
+		ei->i_projid = EXT4_I(dir)->i_projid;
+	else
+		ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
+
+	if (!(i_flags & EXT4_EA_INODE_FL)) {
+		err = fscrypt_prepare_new_inode(dir, inode, &encrypt);
+		if (err)
+			goto out;
+	}
+
+	err = dquot_initialize(inode);
+	if (err)
+		goto out;
+
+	if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
+		ret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt);
+		if (ret2 < 0) {
+			err = ret2;
+			goto out;
+		}
+		nblocks += ret2;
+	}
+
+	if (!goal)
+		goal = sbi->s_inode_goal;
+
+	if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
+		group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
+		ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
+		ret2 = 0;
+		goto got_group;
+	}
+
+	if (S_ISDIR(mode))
+		ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
+	else
+		ret2 = find_group_other(sb, dir, &group, mode);
+
+got_group:
+	EXT4_I(dir)->i_last_alloc_group = group;
+	err = -ENOSPC;
+	if (ret2 == -1)
+		goto out;
+
+	/*
+	 * Normally we will only go through one pass of this loop,
+	 * unless we get unlucky and it turns out the group we selected
+	 * had its last inode grabbed by someone else.
+	 */
+	for (i = 0; i < ngroups; i++, ino = 0) {
+		err = -EIO;
+
+		gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
+		if (!gdp)
+			goto out;
+
+		/*
+		 * Check free inodes count before loading bitmap.
+		 */
+		if (ext4_free_inodes_count(sb, gdp) == 0)
+			goto next_group;
+
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+			grp = ext4_get_group_info(sb, group);
+			/*
+			 * Skip groups with already-known suspicious inode
+			 * tables
+			 */
+			if (!grp || EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
+				goto next_group;
+		}
+
+		brelse(inode_bitmap_bh);
+		inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
+		/* Skip groups with suspicious inode tables */
+		if (((!(sbi->s_mount_state & EXT4_FC_REPLAY))
+		     && EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) ||
+		    IS_ERR(inode_bitmap_bh)) {
+			inode_bitmap_bh = NULL;
+			goto next_group;
+		}
+
+repeat_in_this_group:
+		ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
+		if (!ret2)
+			goto next_group;
+
+		if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
+			ext4_error(sb, "reserved inode found cleared - "
+				   "inode=%lu", ino + 1);
+			ext4_mark_group_bitmap_corrupted(sb, group,
+					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
+			goto next_group;
+		}
+
+		if ((!(sbi->s_mount_state & EXT4_FC_REPLAY)) && !handle) {
+			BUG_ON(nblocks <= 0);
+			handle = __ext4_journal_start_sb(dir->i_sb, line_no,
+				 handle_type, nblocks, 0,
+				 ext4_trans_default_revoke_credits(sb));
+			if (IS_ERR(handle)) {
+				err = PTR_ERR(handle);
+				ext4_std_error(sb, err);
+				goto out;
+			}
+		}
+		BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
+		if (err) {
+			ext4_std_error(sb, err);
+			goto out;
+		}
+		ext4_lock_group(sb, group);
+		ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
+		if (ret2) {
+			/* Someone already took the bit. Repeat the search
+			 * with lock held.
+			 */
+			ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
+			if (ret2) {
+				ext4_set_bit(ino, inode_bitmap_bh->b_data);
+				ret2 = 0;
+			} else {
+				ret2 = 1; /* we didn't grab the inode */
+			}
+		}
+		ext4_unlock_group(sb, group);
+		ino++;		/* the inode bitmap is zero-based */
+		if (!ret2)
+			goto got; /* we grabbed the inode! */
+
+		if (ino < EXT4_INODES_PER_GROUP(sb))
+			goto repeat_in_this_group;
+next_group:
+		if (++group == ngroups)
+			group = 0;
+	}
+	err = -ENOSPC;
+	goto out;
+
+got:
+	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto out;
+	}
+
+	BUFFER_TRACE(group_desc_bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, group_desc_bh);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto out;
+	}
+
+	/* We may have to initialize the block bitmap if it isn't already */
+	if (ext4_has_group_desc_csum(sb) &&
+	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+		struct buffer_head *block_bitmap_bh;
+
+		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (IS_ERR(block_bitmap_bh)) {
+			err = PTR_ERR(block_bitmap_bh);
+			goto out;
+		}
+		BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
+		err = ext4_journal_get_write_access(handle, block_bitmap_bh);
+		if (err) {
+			brelse(block_bitmap_bh);
+			ext4_std_error(sb, err);
+			goto out;
+		}
+
+		BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
+		err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
+
+		/* recheck and clear flag under lock if we still need to */
+		ext4_lock_group(sb, group);
+		if (ext4_has_group_desc_csum(sb) &&
+		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+			ext4_free_group_clusters_set(sb, gdp,
+				ext4_free_clusters_after_init(sb, group, gdp));
+			ext4_block_bitmap_csum_set(sb, group, gdp,
+						   block_bitmap_bh);
+			ext4_group_desc_csum_set(sb, group, gdp);
+		}
+		ext4_unlock_group(sb, group);
+		brelse(block_bitmap_bh);
+
+		if (err) {
+			ext4_std_error(sb, err);
+			goto out;
+		}
+	}
+
+	/* Update the relevant bg descriptor fields */
+	if (ext4_has_group_desc_csum(sb)) {
+		int free;
+		struct ext4_group_info *grp = NULL;
+
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+			grp = ext4_get_group_info(sb, group);
+			if (!grp) {
+				err = -EFSCORRUPTED;
+				goto out;
+			}
+			down_read(&grp->alloc_sem); /*
+						     * protect vs itable
+						     * lazyinit
+						     */
+		}
+		ext4_lock_group(sb, group); /* while we modify the bg desc */
+		free = EXT4_INODES_PER_GROUP(sb) -
+			ext4_itable_unused_count(sb, gdp);
+		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
+			free = 0;
+		}
+		/*
+		 * Check the relative inode number against the last used
+		 * relative inode number in this group. if it is greater
+		 * we need to update the bg_itable_unused count
+		 */
+		if (ino > free)
+			ext4_itable_unused_set(sb, gdp,
+					(EXT4_INODES_PER_GROUP(sb) - ino));
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY))
+			up_read(&grp->alloc_sem);
+	} else {
+		ext4_lock_group(sb, group);
+	}
+
+	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
+	if (S_ISDIR(mode)) {
+		ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
+		if (sbi->s_log_groups_per_flex) {
+			ext4_group_t f = ext4_flex_group(sbi, group);
+
+			atomic_inc(&sbi_array_rcu_deref(sbi, s_flex_groups,
+							f)->used_dirs);
+		}
+	}
+	if (ext4_has_group_desc_csum(sb)) {
+		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
+					   EXT4_INODES_PER_GROUP(sb) / 8);
+		ext4_group_desc_csum_set(sb, group, gdp);
+	}
+	ext4_unlock_group(sb, group);
+
+	BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto out;
+	}
+
+	percpu_counter_dec(&sbi->s_freeinodes_counter);
+	if (S_ISDIR(mode))
+		percpu_counter_inc(&sbi->s_dirs_counter);
+
+	if (sbi->s_log_groups_per_flex) {
+		flex_group = ext4_flex_group(sbi, group);
+		atomic_dec(&sbi_array_rcu_deref(sbi, s_flex_groups,
+						flex_group)->free_inodes);
+	}
+
+	inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
+	/* This is the optimal IO size (for stat), not the fs block size */
+	inode->i_blocks = 0;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	ei->i_crtime = inode->i_mtime;
+
+	memset(ei->i_data, 0, sizeof(ei->i_data));
+	ei->i_dir_start_lookup = 0;
+	ei->i_disksize = 0;
+
+	/* Don't inherit extent flag from directory, amongst others. */
+	ei->i_flags =
+		ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
+	ei->i_flags |= i_flags;
+	ei->i_file_acl = 0;
+	ei->i_dtime = 0;
+	ei->i_block_group = group;
+	ei->i_last_alloc_group = ~0;
+
+	ext4_set_inode_flags(inode, true);
+	if (IS_DIRSYNC(inode))
+		ext4_handle_sync(handle);
+	if (insert_inode_locked(inode) < 0) {
+		/*
+		 * Likely a bitmap corruption causing inode to be allocated
+		 * twice.
+		 */
+		err = -EIO;
+		ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
+			   inode->i_ino);
+		ext4_mark_group_bitmap_corrupted(sb, group,
+					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
+		goto out;
+	}
+	inode->i_generation = prandom_u32();
+
+	/* Precompute checksum seed for inode metadata */
+	if (ext4_has_metadata_csum(sb)) {
+		__u32 csum;
+		__le32 inum = cpu_to_le32(inode->i_ino);
+		__le32 gen = cpu_to_le32(inode->i_generation);
+		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
+				   sizeof(inum));
+		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
+					      sizeof(gen));
+	}
+
+	ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
+	ext4_set_inode_state(inode, EXT4_STATE_NEW);
+
+	ei->i_extra_isize = sbi->s_want_extra_isize;
+	ei->i_inline_off = 0;
+	if (ext4_has_feature_inline_data(sb) &&
+	    (!(ei->i_flags & EXT4_DAX_FL) || S_ISDIR(mode)))
+		ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+	ret = inode;
+	err = dquot_alloc_inode(inode);
+	if (err)
+		goto fail_drop;
+
+	/*
+	 * Since the encryption xattr will always be unique, create it first so
+	 * that it's less likely to end up in an external xattr block and
+	 * prevent its deduplication.
+	 */
+	if (encrypt) {
+		err = fscrypt_set_context(inode, handle);
+		if (err)
+			goto fail_free_drop;
+	}
+
+	if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
+		err = ext4_init_acl(handle, inode, dir);
+		if (err)
+			goto fail_free_drop;
+
+		err = ext4_init_security(handle, inode, dir, qstr);
+		if (err)
+			goto fail_free_drop;
+	}
+
+	if (ext4_has_feature_extents(sb)) {
+		/* set extent flag only for directory, file and normal symlink*/
+		if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
+			ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
+			ext4_ext_tree_init(handle, inode);
+		}
+	}
+
+	if (ext4_handle_valid(handle)) {
+		ei->i_sync_tid = handle->h_transaction->t_tid;
+		ei->i_datasync_tid = handle->h_transaction->t_tid;
+	}
+
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto fail_free_drop;
+	}
+
+	ext4_debug("allocating inode %lu\n", inode->i_ino);
+	trace_ext4_allocate_inode(inode, dir, mode);
+	brelse(inode_bitmap_bh);
+	return ret;
+
+fail_free_drop:
+	dquot_free_inode(inode);
+fail_drop:
+	clear_nlink(inode);
+	unlock_new_inode(inode);
+out:
+	dquot_drop(inode);
+	inode->i_flags |= S_NOQUOTA;
+	iput(inode);
+	brelse(inode_bitmap_bh);
+	return ERR_PTR(err);
+}
+
+/* Verify that we are loading a valid orphan from disk */
+struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
+{
+	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
+	ext4_group_t block_group;
+	int bit;
+	struct buffer_head *bitmap_bh = NULL;
+	struct inode *inode = NULL;
+	int err = -EFSCORRUPTED;
+
+	if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
+		goto bad_orphan;
+
+	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
+	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
+	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
+	if (IS_ERR(bitmap_bh))
+		return ERR_CAST(bitmap_bh);
+
+	/* Having the inode bit set should be a 100% indicator that this
+	 * is a valid orphan (no e2fsck run on fs).  Orphans also include
+	 * inodes that were being truncated, so we can't check i_nlink==0.
+	 */
+	if (!ext4_test_bit(bit, bitmap_bh->b_data))
+		goto bad_orphan;
+
+	inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		ext4_error_err(sb, -err,
+			       "couldn't read orphan inode %lu (err %d)",
+			       ino, err);
+		brelse(bitmap_bh);
+		return inode;
+	}
+
+	/*
+	 * If the orphans has i_nlinks > 0 then it should be able to
+	 * be truncated, otherwise it won't be removed from the orphan
+	 * list during processing and an infinite loop will result.
+	 * Similarly, it must not be a bad inode.
+	 */
+	if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
+	    is_bad_inode(inode))
+		goto bad_orphan;
+
+	if (NEXT_ORPHAN(inode) > max_ino)
+		goto bad_orphan;
+	brelse(bitmap_bh);
+	return inode;
+
+bad_orphan:
+	ext4_error(sb, "bad orphan inode %lu", ino);
+	if (bitmap_bh)
+		printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
+		       bit, (unsigned long long)bitmap_bh->b_blocknr,
+		       ext4_test_bit(bit, bitmap_bh->b_data));
+	if (inode) {
+		printk(KERN_ERR "is_bad_inode(inode)=%d\n",
+		       is_bad_inode(inode));
+		printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
+		       NEXT_ORPHAN(inode));
+		printk(KERN_ERR "max_ino=%lu\n", max_ino);
+		printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
+		/* Avoid freeing blocks if we got a bad deleted inode */
+		if (inode->i_nlink == 0)
+			inode->i_blocks = 0;
+		iput(inode);
+	}
+	brelse(bitmap_bh);
+	return ERR_PTR(err);
+}
+
+unsigned long ext4_count_free_inodes(struct super_block *sb)
+{
+	unsigned long desc_count;
+	struct ext4_group_desc *gdp;
+	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
+#ifdef EXT4FS_DEBUG
+	struct ext4_super_block *es;
+	unsigned long bitmap_count, x;
+	struct buffer_head *bitmap_bh = NULL;
+
+	es = EXT4_SB(sb)->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		desc_count += ext4_free_inodes_count(sb, gdp);
+		brelse(bitmap_bh);
+		bitmap_bh = ext4_read_inode_bitmap(sb, i);
+		if (IS_ERR(bitmap_bh)) {
+			bitmap_bh = NULL;
+			continue;
+		}
+
+		x = ext4_count_free(bitmap_bh->b_data,
+				    EXT4_INODES_PER_GROUP(sb) / 8);
+		printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
+			(unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
+		bitmap_count += x;
+	}
+	brelse(bitmap_bh);
+	printk(KERN_DEBUG "ext4_count_free_inodes: "
+	       "stored = %u, computed = %lu, %lu\n",
+	       le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
+	return desc_count;
+#else
+	desc_count = 0;
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		desc_count += ext4_free_inodes_count(sb, gdp);
+		cond_resched();
+	}
+	return desc_count;
+#endif
+}
+
+/* Called at mount-time, super-block is locked */
+unsigned long ext4_count_dirs(struct super_block * sb)
+{
+	unsigned long count = 0;
+	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
+
+	for (i = 0; i < ngroups; i++) {
+		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		count += ext4_used_dirs_count(sb, gdp);
+	}
+	return count;
+}
+
+/*
+ * Zeroes not yet zeroed inode table - just write zeroes through the whole
+ * inode table. Must be called without any spinlock held. The only place
+ * where it is called from on active part of filesystem is ext4lazyinit
+ * thread, so we do not need any special locks, however we have to prevent
+ * inode allocation from the current group, so we take alloc_sem lock, to
+ * block ext4_new_inode() until we are finished.
+ */
+int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
+				 int barrier)
+{
+	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_desc *gdp = NULL;
+	struct buffer_head *group_desc_bh;
+	handle_t *handle;
+	ext4_fsblk_t blk;
+	int num, ret = 0, used_blks = 0;
+	unsigned long used_inos = 0;
+
+	/* This should not happen, but just to be sure check this */
+	if (sb_rdonly(sb)) {
+		ret = 1;
+		goto out;
+	}
+
+	gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
+	if (!gdp || !grp)
+		goto out;
+
+	/*
+	 * We do not need to lock this, because we are the only one
+	 * handling this flag.
+	 */
+	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
+		goto out;
+
+	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out;
+	}
+
+	down_write(&grp->alloc_sem);
+	/*
+	 * If inode bitmap was already initialized there may be some
+	 * used inodes so we need to skip blocks with used inodes in
+	 * inode table.
+	 */
+	if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
+		used_inos = EXT4_INODES_PER_GROUP(sb) -
+			    ext4_itable_unused_count(sb, gdp);
+		used_blks = DIV_ROUND_UP(used_inos, sbi->s_inodes_per_block);
+
+		/* Bogus inode unused count? */
+		if (used_blks < 0 || used_blks > sbi->s_itb_per_group) {
+			ext4_error(sb, "Something is wrong with group %u: "
+				   "used itable blocks: %d; "
+				   "itable unused count: %u",
+				   group, used_blks,
+				   ext4_itable_unused_count(sb, gdp));
+			ret = 1;
+			goto err_out;
+		}
+
+		used_inos += group * EXT4_INODES_PER_GROUP(sb);
+		/*
+		 * Are there some uninitialized inodes in the inode table
+		 * before the first normal inode?
+		 */
+		if ((used_blks != sbi->s_itb_per_group) &&
+		     (used_inos < EXT4_FIRST_INO(sb))) {
+			ext4_error(sb, "Something is wrong with group %u: "
+				   "itable unused count: %u; "
+				   "itables initialized count: %ld",
+				   group, ext4_itable_unused_count(sb, gdp),
+				   used_inos);
+			ret = 1;
+			goto err_out;
+		}
+	}
+
+	blk = ext4_inode_table(sb, gdp) + used_blks;
+	num = sbi->s_itb_per_group - used_blks;
+
+	BUFFER_TRACE(group_desc_bh, "get_write_access");
+	ret = ext4_journal_get_write_access(handle,
+					    group_desc_bh);
+	if (ret)
+		goto err_out;
+
+	/*
+	 * Skip zeroout if the inode table is full. But we set the ZEROED
+	 * flag anyway, because obviously, when it is full it does not need
+	 * further zeroing.
+	 */
+	if (unlikely(num == 0))
+		goto skip_zeroout;
+
+	ext4_debug("going to zero out inode table in group %d\n",
+		   group);
+	ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
+	if (ret < 0)
+		goto err_out;
+	if (barrier)
+		blkdev_issue_flush(sb->s_bdev, GFP_NOFS);
+
+skip_zeroout:
+	ext4_lock_group(sb, group);
+	gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
+	ext4_group_desc_csum_set(sb, group, gdp);
+	ext4_unlock_group(sb, group);
+
+	BUFFER_TRACE(group_desc_bh,
+		     "call ext4_handle_dirty_metadata");
+	ret = ext4_handle_dirty_metadata(handle, NULL,
+					 group_desc_bh);
+
+err_out:
+	up_write(&grp->alloc_sem);
+	ext4_journal_stop(handle);
+out:
+	return ret;
+}
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
new file mode 100644
index 000000000..c2bb2ff3f
--- /dev/null
+++ b/fs/ext4/indirect.c
@@ -0,0 +1,1476 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/indirect.c
+ *
+ *  from
+ *
+ *  linux/fs/ext4/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Goal-directed block allocation by Stephen Tweedie
+ *	(sct@redhat.com), 1993, 1998
+ */
+
+#include "ext4_jbd2.h"
+#include "truncate.h"
+#include <linux/dax.h>
+#include <linux/uio.h>
+
+#include <trace/events/ext4.h>
+
+typedef struct {
+	__le32	*p;
+	__le32	key;
+	struct buffer_head *bh;
+} Indirect;
+
+static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
+{
+	p->key = *(p->p = v);
+	p->bh = bh;
+}
+
+/**
+ *	ext4_block_to_path - parse the block number into array of offsets
+ *	@inode: inode in question (we are only interested in its superblock)
+ *	@i_block: block number to be parsed
+ *	@offsets: array to store the offsets in
+ *	@boundary: set this non-zero if the referred-to block is likely to be
+ *	       followed (on disk) by an indirect block.
+ *
+ *	To store the locations of file's data ext4 uses a data structure common
+ *	for UNIX filesystems - tree of pointers anchored in the inode, with
+ *	data blocks at leaves and indirect blocks in intermediate nodes.
+ *	This function translates the block number into path in that tree -
+ *	return value is the path length and @offsets[n] is the offset of
+ *	pointer to (n+1)th node in the nth one. If @block is out of range
+ *	(negative or too large) warning is printed and zero returned.
+ *
+ *	Note: function doesn't find node addresses, so no IO is needed. All
+ *	we need to know is the capacity of indirect blocks (taken from the
+ *	inode->i_sb).
+ */
+
+/*
+ * Portability note: the last comparison (check that we fit into triple
+ * indirect block) is spelled differently, because otherwise on an
+ * architecture with 32-bit longs and 8Kb pages we might get into trouble
+ * if our filesystem had 8Kb blocks. We might use long long, but that would
+ * kill us on x86. Oh, well, at least the sign propagation does not matter -
+ * i_block would have to be negative in the very beginning, so we would not
+ * get there at all.
+ */
+
+static int ext4_block_to_path(struct inode *inode,
+			      ext4_lblk_t i_block,
+			      ext4_lblk_t offsets[4], int *boundary)
+{
+	int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+	int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
+	const long direct_blocks = EXT4_NDIR_BLOCKS,
+		indirect_blocks = ptrs,
+		double_blocks = (1 << (ptrs_bits * 2));
+	int n = 0;
+	int final = 0;
+
+	if (i_block < direct_blocks) {
+		offsets[n++] = i_block;
+		final = direct_blocks;
+	} else if ((i_block -= direct_blocks) < indirect_blocks) {
+		offsets[n++] = EXT4_IND_BLOCK;
+		offsets[n++] = i_block;
+		final = ptrs;
+	} else if ((i_block -= indirect_blocks) < double_blocks) {
+		offsets[n++] = EXT4_DIND_BLOCK;
+		offsets[n++] = i_block >> ptrs_bits;
+		offsets[n++] = i_block & (ptrs - 1);
+		final = ptrs;
+	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
+		offsets[n++] = EXT4_TIND_BLOCK;
+		offsets[n++] = i_block >> (ptrs_bits * 2);
+		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
+		offsets[n++] = i_block & (ptrs - 1);
+		final = ptrs;
+	} else {
+		ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
+			     i_block + direct_blocks +
+			     indirect_blocks + double_blocks, inode->i_ino);
+	}
+	if (boundary)
+		*boundary = final - 1 - (i_block & (ptrs - 1));
+	return n;
+}
+
+/**
+ *	ext4_get_branch - read the chain of indirect blocks leading to data
+ *	@inode: inode in question
+ *	@depth: depth of the chain (1 - direct pointer, etc.)
+ *	@offsets: offsets of pointers in inode/indirect blocks
+ *	@chain: place to store the result
+ *	@err: here we store the error value
+ *
+ *	Function fills the array of triples <key, p, bh> and returns %NULL
+ *	if everything went OK or the pointer to the last filled triple
+ *	(incomplete one) otherwise. Upon the return chain[i].key contains
+ *	the number of (i+1)-th block in the chain (as it is stored in memory,
+ *	i.e. little-endian 32-bit), chain[i].p contains the address of that
+ *	number (it points into struct inode for i==0 and into the bh->b_data
+ *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
+ *	block for i>0 and NULL for i==0. In other words, it holds the block
+ *	numbers of the chain, addresses they were taken from (and where we can
+ *	verify that chain did not change) and buffer_heads hosting these
+ *	numbers.
+ *
+ *	Function stops when it stumbles upon zero pointer (absent block)
+ *		(pointer to last triple returned, *@err == 0)
+ *	or when it gets an IO error reading an indirect block
+ *		(ditto, *@err == -EIO)
+ *	or when it reads all @depth-1 indirect blocks successfully and finds
+ *	the whole chain, all way to the data (returns %NULL, *err == 0).
+ *
+ *      Need to be called with
+ *      down_read(&EXT4_I(inode)->i_data_sem)
+ */
+static Indirect *ext4_get_branch(struct inode *inode, int depth,
+				 ext4_lblk_t  *offsets,
+				 Indirect chain[4], int *err)
+{
+	struct super_block *sb = inode->i_sb;
+	Indirect *p = chain;
+	struct buffer_head *bh;
+	unsigned int key;
+	int ret = -EIO;
+
+	*err = 0;
+	/* i_data is not going away, no lock needed */
+	add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
+	if (!p->key)
+		goto no_block;
+	while (--depth) {
+		key = le32_to_cpu(p->key);
+		if (key > ext4_blocks_count(EXT4_SB(sb)->s_es)) {
+			/* the block was out of range */
+			ret = -EFSCORRUPTED;
+			goto failure;
+		}
+		bh = sb_getblk(sb, key);
+		if (unlikely(!bh)) {
+			ret = -ENOMEM;
+			goto failure;
+		}
+
+		if (!bh_uptodate_or_lock(bh)) {
+			if (ext4_read_bh(bh, 0, NULL) < 0) {
+				put_bh(bh);
+				goto failure;
+			}
+			/* validate block references */
+			if (ext4_check_indirect_blockref(inode, bh)) {
+				put_bh(bh);
+				goto failure;
+			}
+		}
+
+		add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
+		/* Reader: end */
+		if (!p->key)
+			goto no_block;
+	}
+	return NULL;
+
+failure:
+	*err = ret;
+no_block:
+	return p;
+}
+
+/**
+ *	ext4_find_near - find a place for allocation with sufficient locality
+ *	@inode: owner
+ *	@ind: descriptor of indirect block.
+ *
+ *	This function returns the preferred place for block allocation.
+ *	It is used when heuristic for sequential allocation fails.
+ *	Rules are:
+ *	  + if there is a block to the left of our position - allocate near it.
+ *	  + if pointer will live in indirect block - allocate near that block.
+ *	  + if pointer will live in inode - allocate in the same
+ *	    cylinder group.
+ *
+ * In the latter case we colour the starting block by the callers PID to
+ * prevent it from clashing with concurrent allocations for a different inode
+ * in the same block group.   The PID is used here so that functionally related
+ * files will be close-by on-disk.
+ *
+ *	Caller must make sure that @ind is valid and will stay that way.
+ */
+static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
+	__le32 *p;
+
+	/* Try to find previous block */
+	for (p = ind->p - 1; p >= start; p--) {
+		if (*p)
+			return le32_to_cpu(*p);
+	}
+
+	/* No such thing, so let's try location of indirect block */
+	if (ind->bh)
+		return ind->bh->b_blocknr;
+
+	/*
+	 * It is going to be referred to from the inode itself? OK, just put it
+	 * into the same cylinder group then.
+	 */
+	return ext4_inode_to_goal_block(inode);
+}
+
+/**
+ *	ext4_find_goal - find a preferred place for allocation.
+ *	@inode: owner
+ *	@block:  block we want
+ *	@partial: pointer to the last triple within a chain
+ *
+ *	Normally this function find the preferred place for block allocation,
+ *	returns it.
+ *	Because this is only used for non-extent files, we limit the block nr
+ *	to 32 bits.
+ */
+static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
+				   Indirect *partial)
+{
+	ext4_fsblk_t goal;
+
+	/*
+	 * XXX need to get goal block from mballoc's data structures
+	 */
+
+	goal = ext4_find_near(inode, partial);
+	goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
+	return goal;
+}
+
+/**
+ *	ext4_blks_to_allocate - Look up the block map and count the number
+ *	of direct blocks need to be allocated for the given branch.
+ *
+ *	@branch: chain of indirect blocks
+ *	@k: number of blocks need for indirect blocks
+ *	@blks: number of data blocks to be mapped.
+ *	@blocks_to_boundary:  the offset in the indirect block
+ *
+ *	return the total number of blocks to be allocate, including the
+ *	direct and indirect blocks.
+ */
+static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
+				 int blocks_to_boundary)
+{
+	unsigned int count = 0;
+
+	/*
+	 * Simple case, [t,d]Indirect block(s) has not allocated yet
+	 * then it's clear blocks on that path have not allocated
+	 */
+	if (k > 0) {
+		/* right now we don't handle cross boundary allocation */
+		if (blks < blocks_to_boundary + 1)
+			count += blks;
+		else
+			count += blocks_to_boundary + 1;
+		return count;
+	}
+
+	count++;
+	while (count < blks && count <= blocks_to_boundary &&
+		le32_to_cpu(*(branch[0].p + count)) == 0) {
+		count++;
+	}
+	return count;
+}
+
+/**
+ * ext4_alloc_branch() - allocate and set up a chain of blocks
+ * @handle: handle for this transaction
+ * @ar: structure describing the allocation request
+ * @indirect_blks: number of allocated indirect blocks
+ * @offsets: offsets (in the blocks) to store the pointers to next.
+ * @branch: place to store the chain in.
+ *
+ *	This function allocates blocks, zeroes out all but the last one,
+ *	links them into chain and (if we are synchronous) writes them to disk.
+ *	In other words, it prepares a branch that can be spliced onto the
+ *	inode. It stores the information about that chain in the branch[], in
+ *	the same format as ext4_get_branch() would do. We are calling it after
+ *	we had read the existing part of chain and partial points to the last
+ *	triple of that (one with zero ->key). Upon the exit we have the same
+ *	picture as after the successful ext4_get_block(), except that in one
+ *	place chain is disconnected - *branch->p is still zero (we did not
+ *	set the last link), but branch->key contains the number that should
+ *	be placed into *branch->p to fill that gap.
+ *
+ *	If allocation fails we free all blocks we've allocated (and forget
+ *	their buffer_heads) and return the error value the from failed
+ *	ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
+ *	as described above and return 0.
+ */
+static int ext4_alloc_branch(handle_t *handle,
+			     struct ext4_allocation_request *ar,
+			     int indirect_blks, ext4_lblk_t *offsets,
+			     Indirect *branch)
+{
+	struct buffer_head *		bh;
+	ext4_fsblk_t			b, new_blocks[4];
+	__le32				*p;
+	int				i, j, err, len = 1;
+
+	for (i = 0; i <= indirect_blks; i++) {
+		if (i == indirect_blks) {
+			new_blocks[i] = ext4_mb_new_blocks(handle, ar, &err);
+		} else {
+			ar->goal = new_blocks[i] = ext4_new_meta_blocks(handle,
+					ar->inode, ar->goal,
+					ar->flags & EXT4_MB_DELALLOC_RESERVED,
+					NULL, &err);
+			/* Simplify error cleanup... */
+			branch[i+1].bh = NULL;
+		}
+		if (err) {
+			i--;
+			goto failed;
+		}
+		branch[i].key = cpu_to_le32(new_blocks[i]);
+		if (i == 0)
+			continue;
+
+		bh = branch[i].bh = sb_getblk(ar->inode->i_sb, new_blocks[i-1]);
+		if (unlikely(!bh)) {
+			err = -ENOMEM;
+			goto failed;
+		}
+		lock_buffer(bh);
+		BUFFER_TRACE(bh, "call get_create_access");
+		err = ext4_journal_get_create_access(handle, bh);
+		if (err) {
+			unlock_buffer(bh);
+			goto failed;
+		}
+
+		memset(bh->b_data, 0, bh->b_size);
+		p = branch[i].p = (__le32 *) bh->b_data + offsets[i];
+		b = new_blocks[i];
+
+		if (i == indirect_blks)
+			len = ar->len;
+		for (j = 0; j < len; j++)
+			*p++ = cpu_to_le32(b++);
+
+		BUFFER_TRACE(bh, "marking uptodate");
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+
+		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+		err = ext4_handle_dirty_metadata(handle, ar->inode, bh);
+		if (err)
+			goto failed;
+	}
+	return 0;
+failed:
+	if (i == indirect_blks) {
+		/* Free data blocks */
+		ext4_free_blocks(handle, ar->inode, NULL, new_blocks[i],
+				 ar->len, 0);
+		i--;
+	}
+	for (; i >= 0; i--) {
+		/*
+		 * We want to ext4_forget() only freshly allocated indirect
+		 * blocks. Buffer for new_blocks[i] is at branch[i+1].bh
+		 * (buffer at branch[0].bh is indirect block / inode already
+		 * existing before ext4_alloc_branch() was called). Also
+		 * because blocks are freshly allocated, we don't need to
+		 * revoke them which is why we don't set
+		 * EXT4_FREE_BLOCKS_METADATA.
+		 */
+		ext4_free_blocks(handle, ar->inode, branch[i+1].bh,
+				 new_blocks[i], 1,
+				 branch[i+1].bh ? EXT4_FREE_BLOCKS_FORGET : 0);
+	}
+	return err;
+}
+
+/**
+ * ext4_splice_branch() - splice the allocated branch onto inode.
+ * @handle: handle for this transaction
+ * @ar: structure describing the allocation request
+ * @where: location of missing link
+ * @num:   number of indirect blocks we are adding
+ *
+ * This function fills the missing link and does all housekeeping needed in
+ * inode (->i_blocks, etc.). In case of success we end up with the full
+ * chain to new block and return 0.
+ */
+static int ext4_splice_branch(handle_t *handle,
+			      struct ext4_allocation_request *ar,
+			      Indirect *where, int num)
+{
+	int i;
+	int err = 0;
+	ext4_fsblk_t current_block;
+
+	/*
+	 * If we're splicing into a [td]indirect block (as opposed to the
+	 * inode) then we need to get write access to the [td]indirect block
+	 * before the splice.
+	 */
+	if (where->bh) {
+		BUFFER_TRACE(where->bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, where->bh);
+		if (err)
+			goto err_out;
+	}
+	/* That's it */
+
+	*where->p = where->key;
+
+	/*
+	 * Update the host buffer_head or inode to point to more just allocated
+	 * direct blocks blocks
+	 */
+	if (num == 0 && ar->len > 1) {
+		current_block = le32_to_cpu(where->key) + 1;
+		for (i = 1; i < ar->len; i++)
+			*(where->p + i) = cpu_to_le32(current_block++);
+	}
+
+	/* We are done with atomic stuff, now do the rest of housekeeping */
+	/* had we spliced it onto indirect block? */
+	if (where->bh) {
+		/*
+		 * If we spliced it onto an indirect block, we haven't
+		 * altered the inode.  Note however that if it is being spliced
+		 * onto an indirect block at the very end of the file (the
+		 * file is growing) then we *will* alter the inode to reflect
+		 * the new i_size.  But that is not done here - it is done in
+		 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
+		 */
+		jbd_debug(5, "splicing indirect only\n");
+		BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
+		err = ext4_handle_dirty_metadata(handle, ar->inode, where->bh);
+		if (err)
+			goto err_out;
+	} else {
+		/*
+		 * OK, we spliced it into the inode itself on a direct block.
+		 */
+		err = ext4_mark_inode_dirty(handle, ar->inode);
+		if (unlikely(err))
+			goto err_out;
+		jbd_debug(5, "splicing direct\n");
+	}
+	return err;
+
+err_out:
+	for (i = 1; i <= num; i++) {
+		/*
+		 * branch[i].bh is newly allocated, so there is no
+		 * need to revoke the block, which is why we don't
+		 * need to set EXT4_FREE_BLOCKS_METADATA.
+		 */
+		ext4_free_blocks(handle, ar->inode, where[i].bh, 0, 1,
+				 EXT4_FREE_BLOCKS_FORGET);
+	}
+	ext4_free_blocks(handle, ar->inode, NULL, le32_to_cpu(where[num].key),
+			 ar->len, 0);
+
+	return err;
+}
+
+/*
+ * The ext4_ind_map_blocks() function handles non-extents inodes
+ * (i.e., using the traditional indirect/double-indirect i_blocks
+ * scheme) for ext4_map_blocks().
+ *
+ * Allocation strategy is simple: if we have to allocate something, we will
+ * have to go the whole way to leaf. So let's do it before attaching anything
+ * to tree, set linkage between the newborn blocks, write them if sync is
+ * required, recheck the path, free and repeat if check fails, otherwise
+ * set the last missing link (that will protect us from any truncate-generated
+ * removals - all blocks on the path are immune now) and possibly force the
+ * write on the parent block.
+ * That has a nice additional property: no special recovery from the failed
+ * allocations is needed - we simply release blocks and do not touch anything
+ * reachable from inode.
+ *
+ * `handle' can be NULL if create == 0.
+ *
+ * return > 0, # of blocks mapped or allocated.
+ * return = 0, if plain lookup failed.
+ * return < 0, error case.
+ *
+ * The ext4_ind_get_blocks() function should be called with
+ * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
+ * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
+ * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
+ * blocks.
+ */
+int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
+			struct ext4_map_blocks *map,
+			int flags)
+{
+	struct ext4_allocation_request ar;
+	int err = -EIO;
+	ext4_lblk_t offsets[4];
+	Indirect chain[4];
+	Indirect *partial;
+	int indirect_blks;
+	int blocks_to_boundary = 0;
+	int depth;
+	int count = 0;
+	ext4_fsblk_t first_block = 0;
+
+	trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
+	J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
+	J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
+	depth = ext4_block_to_path(inode, map->m_lblk, offsets,
+				   &blocks_to_boundary);
+
+	if (depth == 0)
+		goto out;
+
+	partial = ext4_get_branch(inode, depth, offsets, chain, &err);
+
+	/* Simplest case - block found, no allocation needed */
+	if (!partial) {
+		first_block = le32_to_cpu(chain[depth - 1].key);
+		count++;
+		/*map more blocks*/
+		while (count < map->m_len && count <= blocks_to_boundary) {
+			ext4_fsblk_t blk;
+
+			blk = le32_to_cpu(*(chain[depth-1].p + count));
+
+			if (blk == first_block + count)
+				count++;
+			else
+				break;
+		}
+		goto got_it;
+	}
+
+	/* Next simple case - plain lookup failed */
+	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
+		unsigned epb = inode->i_sb->s_blocksize / sizeof(u32);
+		int i;
+
+		/*
+		 * Count number blocks in a subtree under 'partial'. At each
+		 * level we count number of complete empty subtrees beyond
+		 * current offset and then descend into the subtree only
+		 * partially beyond current offset.
+		 */
+		count = 0;
+		for (i = partial - chain + 1; i < depth; i++)
+			count = count * epb + (epb - offsets[i] - 1);
+		count++;
+		/* Fill in size of a hole we found */
+		map->m_pblk = 0;
+		map->m_len = min_t(unsigned int, map->m_len, count);
+		goto cleanup;
+	}
+
+	/* Failed read of indirect block */
+	if (err == -EIO)
+		goto cleanup;
+
+	/*
+	 * Okay, we need to do block allocation.
+	*/
+	if (ext4_has_feature_bigalloc(inode->i_sb)) {
+		EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
+				 "non-extent mapped inodes with bigalloc");
+		err = -EFSCORRUPTED;
+		goto out;
+	}
+
+	/* Set up for the direct block allocation */
+	memset(&ar, 0, sizeof(ar));
+	ar.inode = inode;
+	ar.logical = map->m_lblk;
+	if (S_ISREG(inode->i_mode))
+		ar.flags = EXT4_MB_HINT_DATA;
+	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+		ar.flags |= EXT4_MB_DELALLOC_RESERVED;
+	if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
+		ar.flags |= EXT4_MB_USE_RESERVED;
+
+	ar.goal = ext4_find_goal(inode, map->m_lblk, partial);
+
+	/* the number of blocks need to allocate for [d,t]indirect blocks */
+	indirect_blks = (chain + depth) - partial - 1;
+
+	/*
+	 * Next look up the indirect map to count the totoal number of
+	 * direct blocks to allocate for this branch.
+	 */
+	ar.len = ext4_blks_to_allocate(partial, indirect_blks,
+				       map->m_len, blocks_to_boundary);
+
+	/*
+	 * Block out ext4_truncate while we alter the tree
+	 */
+	err = ext4_alloc_branch(handle, &ar, indirect_blks,
+				offsets + (partial - chain), partial);
+
+	/*
+	 * The ext4_splice_branch call will free and forget any buffers
+	 * on the new chain if there is a failure, but that risks using
+	 * up transaction credits, especially for bitmaps where the
+	 * credits cannot be returned.  Can we handle this somehow?  We
+	 * may need to return -EAGAIN upwards in the worst case.  --sct
+	 */
+	if (!err)
+		err = ext4_splice_branch(handle, &ar, partial, indirect_blks);
+	if (err)
+		goto cleanup;
+
+	map->m_flags |= EXT4_MAP_NEW;
+
+	ext4_update_inode_fsync_trans(handle, inode, 1);
+	count = ar.len;
+
+	/*
+	 * Update reserved blocks/metadata blocks after successful block
+	 * allocation which had been deferred till now.
+	 */
+	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+		ext4_da_update_reserve_space(inode, count, 1);
+
+got_it:
+	map->m_flags |= EXT4_MAP_MAPPED;
+	map->m_pblk = le32_to_cpu(chain[depth-1].key);
+	map->m_len = count;
+	if (count > blocks_to_boundary)
+		map->m_flags |= EXT4_MAP_BOUNDARY;
+	err = count;
+	/* Clean up and exit */
+	partial = chain + depth - 1;	/* the whole chain */
+cleanup:
+	while (partial > chain) {
+		BUFFER_TRACE(partial->bh, "call brelse");
+		brelse(partial->bh);
+		partial--;
+	}
+out:
+	trace_ext4_ind_map_blocks_exit(inode, flags, map, err);
+	return err;
+}
+
+/*
+ * Calculate number of indirect blocks touched by mapping @nrblocks logically
+ * contiguous blocks
+ */
+int ext4_ind_trans_blocks(struct inode *inode, int nrblocks)
+{
+	/*
+	 * With N contiguous data blocks, we need at most
+	 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
+	 * 2 dindirect blocks, and 1 tindirect block
+	 */
+	return DIV_ROUND_UP(nrblocks, EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
+}
+
+static int ext4_ind_trunc_restart_fn(handle_t *handle, struct inode *inode,
+				     struct buffer_head *bh, int *dropped)
+{
+	int err;
+
+	if (bh) {
+		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+		err = ext4_handle_dirty_metadata(handle, inode, bh);
+		if (unlikely(err))
+			return err;
+	}
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (unlikely(err))
+		return err;
+	/*
+	 * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
+	 * moment, get_block can be called only for blocks inside i_size since
+	 * page cache has been already dropped and writes are blocked by
+	 * i_mutex. So we can safely drop the i_data_sem here.
+	 */
+	BUG_ON(EXT4_JOURNAL(inode) == NULL);
+	ext4_discard_preallocations(inode, 0);
+	up_write(&EXT4_I(inode)->i_data_sem);
+	*dropped = 1;
+	return 0;
+}
+
+/*
+ * Truncate transactions can be complex and absolutely huge.  So we need to
+ * be able to restart the transaction at a convenient checkpoint to make
+ * sure we don't overflow the journal.
+ *
+ * Try to extend this transaction for the purposes of truncation.  If
+ * extend fails, we restart transaction.
+ */
+static int ext4_ind_truncate_ensure_credits(handle_t *handle,
+					    struct inode *inode,
+					    struct buffer_head *bh,
+					    int revoke_creds)
+{
+	int ret;
+	int dropped = 0;
+
+	ret = ext4_journal_ensure_credits_fn(handle, EXT4_RESERVE_TRANS_BLOCKS,
+			ext4_blocks_for_truncate(inode), revoke_creds,
+			ext4_ind_trunc_restart_fn(handle, inode, bh, &dropped));
+	if (dropped)
+		down_write(&EXT4_I(inode)->i_data_sem);
+	if (ret <= 0)
+		return ret;
+	if (bh) {
+		BUFFER_TRACE(bh, "retaking write access");
+		ret = ext4_journal_get_write_access(handle, bh);
+		if (unlikely(ret))
+			return ret;
+	}
+	return 0;
+}
+
+/*
+ * Probably it should be a library function... search for first non-zero word
+ * or memcmp with zero_page, whatever is better for particular architecture.
+ * Linus?
+ */
+static inline int all_zeroes(__le32 *p, __le32 *q)
+{
+	while (p < q)
+		if (*p++)
+			return 0;
+	return 1;
+}
+
+/**
+ *	ext4_find_shared - find the indirect blocks for partial truncation.
+ *	@inode:	  inode in question
+ *	@depth:	  depth of the affected branch
+ *	@offsets: offsets of pointers in that branch (see ext4_block_to_path)
+ *	@chain:	  place to store the pointers to partial indirect blocks
+ *	@top:	  place to the (detached) top of branch
+ *
+ *	This is a helper function used by ext4_truncate().
+ *
+ *	When we do truncate() we may have to clean the ends of several
+ *	indirect blocks but leave the blocks themselves alive. Block is
+ *	partially truncated if some data below the new i_size is referred
+ *	from it (and it is on the path to the first completely truncated
+ *	data block, indeed).  We have to free the top of that path along
+ *	with everything to the right of the path. Since no allocation
+ *	past the truncation point is possible until ext4_truncate()
+ *	finishes, we may safely do the latter, but top of branch may
+ *	require special attention - pageout below the truncation point
+ *	might try to populate it.
+ *
+ *	We atomically detach the top of branch from the tree, store the
+ *	block number of its root in *@top, pointers to buffer_heads of
+ *	partially truncated blocks - in @chain[].bh and pointers to
+ *	their last elements that should not be removed - in
+ *	@chain[].p. Return value is the pointer to last filled element
+ *	of @chain.
+ *
+ *	The work left to caller to do the actual freeing of subtrees:
+ *		a) free the subtree starting from *@top
+ *		b) free the subtrees whose roots are stored in
+ *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
+ *		c) free the subtrees growing from the inode past the @chain[0].
+ *			(no partially truncated stuff there).  */
+
+static Indirect *ext4_find_shared(struct inode *inode, int depth,
+				  ext4_lblk_t offsets[4], Indirect chain[4],
+				  __le32 *top)
+{
+	Indirect *partial, *p;
+	int k, err;
+
+	*top = 0;
+	/* Make k index the deepest non-null offset + 1 */
+	for (k = depth; k > 1 && !offsets[k-1]; k--)
+		;
+	partial = ext4_get_branch(inode, k, offsets, chain, &err);
+	/* Writer: pointers */
+	if (!partial)
+		partial = chain + k-1;
+	/*
+	 * If the branch acquired continuation since we've looked at it -
+	 * fine, it should all survive and (new) top doesn't belong to us.
+	 */
+	if (!partial->key && *partial->p)
+		/* Writer: end */
+		goto no_top;
+	for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
+		;
+	/*
+	 * OK, we've found the last block that must survive. The rest of our
+	 * branch should be detached before unlocking. However, if that rest
+	 * of branch is all ours and does not grow immediately from the inode
+	 * it's easier to cheat and just decrement partial->p.
+	 */
+	if (p == chain + k - 1 && p > chain) {
+		p->p--;
+	} else {
+		*top = *p->p;
+		/* Nope, don't do this in ext4.  Must leave the tree intact */
+#if 0
+		*p->p = 0;
+#endif
+	}
+	/* Writer: end */
+
+	while (partial > p) {
+		brelse(partial->bh);
+		partial--;
+	}
+no_top:
+	return partial;
+}
+
+/*
+ * Zero a number of block pointers in either an inode or an indirect block.
+ * If we restart the transaction we must again get write access to the
+ * indirect block for further modification.
+ *
+ * We release `count' blocks on disk, but (last - first) may be greater
+ * than `count' because there can be holes in there.
+ *
+ * Return 0 on success, 1 on invalid block range
+ * and < 0 on fatal error.
+ */
+static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
+			     struct buffer_head *bh,
+			     ext4_fsblk_t block_to_free,
+			     unsigned long count, __le32 *first,
+			     __le32 *last)
+{
+	__le32 *p;
+	int	flags = EXT4_FREE_BLOCKS_VALIDATED;
+	int	err;
+
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
+		flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
+	else if (ext4_should_journal_data(inode))
+		flags |= EXT4_FREE_BLOCKS_FORGET;
+
+	if (!ext4_inode_block_valid(inode, block_to_free, count)) {
+		EXT4_ERROR_INODE(inode, "attempt to clear invalid "
+				 "blocks %llu len %lu",
+				 (unsigned long long) block_to_free, count);
+		return 1;
+	}
+
+	err = ext4_ind_truncate_ensure_credits(handle, inode, bh,
+				ext4_free_data_revoke_credits(inode, count));
+	if (err < 0)
+		goto out_err;
+
+	for (p = first; p < last; p++)
+		*p = 0;
+
+	ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
+	return 0;
+out_err:
+	ext4_std_error(inode->i_sb, err);
+	return err;
+}
+
+/**
+ * ext4_free_data - free a list of data blocks
+ * @handle:	handle for this transaction
+ * @inode:	inode we are dealing with
+ * @this_bh:	indirect buffer_head which contains *@first and *@last
+ * @first:	array of block numbers
+ * @last:	points immediately past the end of array
+ *
+ * We are freeing all blocks referred from that array (numbers are stored as
+ * little-endian 32-bit) and updating @inode->i_blocks appropriately.
+ *
+ * We accumulate contiguous runs of blocks to free.  Conveniently, if these
+ * blocks are contiguous then releasing them at one time will only affect one
+ * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
+ * actually use a lot of journal space.
+ *
+ * @this_bh will be %NULL if @first and @last point into the inode's direct
+ * block pointers.
+ */
+static void ext4_free_data(handle_t *handle, struct inode *inode,
+			   struct buffer_head *this_bh,
+			   __le32 *first, __le32 *last)
+{
+	ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
+	unsigned long count = 0;	    /* Number of blocks in the run */
+	__le32 *block_to_free_p = NULL;	    /* Pointer into inode/ind
+					       corresponding to
+					       block_to_free */
+	ext4_fsblk_t nr;		    /* Current block # */
+	__le32 *p;			    /* Pointer into inode/ind
+					       for current block */
+	int err = 0;
+
+	if (this_bh) {				/* For indirect block */
+		BUFFER_TRACE(this_bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, this_bh);
+		/* Important: if we can't update the indirect pointers
+		 * to the blocks, we can't free them. */
+		if (err)
+			return;
+	}
+
+	for (p = first; p < last; p++) {
+		nr = le32_to_cpu(*p);
+		if (nr) {
+			/* accumulate blocks to free if they're contiguous */
+			if (count == 0) {
+				block_to_free = nr;
+				block_to_free_p = p;
+				count = 1;
+			} else if (nr == block_to_free + count) {
+				count++;
+			} else {
+				err = ext4_clear_blocks(handle, inode, this_bh,
+						        block_to_free, count,
+						        block_to_free_p, p);
+				if (err)
+					break;
+				block_to_free = nr;
+				block_to_free_p = p;
+				count = 1;
+			}
+		}
+	}
+
+	if (!err && count > 0)
+		err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
+					count, block_to_free_p, p);
+	if (err < 0)
+		/* fatal error */
+		return;
+
+	if (this_bh) {
+		BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
+
+		/*
+		 * The buffer head should have an attached journal head at this
+		 * point. However, if the data is corrupted and an indirect
+		 * block pointed to itself, it would have been detached when
+		 * the block was cleared. Check for this instead of OOPSing.
+		 */
+		if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
+			ext4_handle_dirty_metadata(handle, inode, this_bh);
+		else
+			EXT4_ERROR_INODE(inode,
+					 "circular indirect block detected at "
+					 "block %llu",
+				(unsigned long long) this_bh->b_blocknr);
+	}
+}
+
+/**
+ *	ext4_free_branches - free an array of branches
+ *	@handle: JBD handle for this transaction
+ *	@inode:	inode we are dealing with
+ *	@parent_bh: the buffer_head which contains *@first and *@last
+ *	@first:	array of block numbers
+ *	@last:	pointer immediately past the end of array
+ *	@depth:	depth of the branches to free
+ *
+ *	We are freeing all blocks referred from these branches (numbers are
+ *	stored as little-endian 32-bit) and updating @inode->i_blocks
+ *	appropriately.
+ */
+static void ext4_free_branches(handle_t *handle, struct inode *inode,
+			       struct buffer_head *parent_bh,
+			       __le32 *first, __le32 *last, int depth)
+{
+	ext4_fsblk_t nr;
+	__le32 *p;
+
+	if (ext4_handle_is_aborted(handle))
+		return;
+
+	if (depth--) {
+		struct buffer_head *bh;
+		int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+		p = last;
+		while (--p >= first) {
+			nr = le32_to_cpu(*p);
+			if (!nr)
+				continue;		/* A hole */
+
+			if (!ext4_inode_block_valid(inode, nr, 1)) {
+				EXT4_ERROR_INODE(inode,
+						 "invalid indirect mapped "
+						 "block %lu (level %d)",
+						 (unsigned long) nr, depth);
+				break;
+			}
+
+			/* Go read the buffer for the next level down */
+			bh = ext4_sb_bread(inode->i_sb, nr, 0);
+
+			/*
+			 * A read failure? Report error and clear slot
+			 * (should be rare).
+			 */
+			if (IS_ERR(bh)) {
+				ext4_error_inode_block(inode, nr, -PTR_ERR(bh),
+						       "Read failure");
+				continue;
+			}
+
+			/* This zaps the entire block.  Bottom up. */
+			BUFFER_TRACE(bh, "free child branches");
+			ext4_free_branches(handle, inode, bh,
+					(__le32 *) bh->b_data,
+					(__le32 *) bh->b_data + addr_per_block,
+					depth);
+			brelse(bh);
+
+			/*
+			 * Everything below this pointer has been
+			 * released.  Now let this top-of-subtree go.
+			 *
+			 * We want the freeing of this indirect block to be
+			 * atomic in the journal with the updating of the
+			 * bitmap block which owns it.  So make some room in
+			 * the journal.
+			 *
+			 * We zero the parent pointer *after* freeing its
+			 * pointee in the bitmaps, so if extend_transaction()
+			 * for some reason fails to put the bitmap changes and
+			 * the release into the same transaction, recovery
+			 * will merely complain about releasing a free block,
+			 * rather than leaking blocks.
+			 */
+			if (ext4_handle_is_aborted(handle))
+				return;
+			if (ext4_ind_truncate_ensure_credits(handle, inode,
+					NULL,
+					ext4_free_metadata_revoke_credits(
+							inode->i_sb, 1)) < 0)
+				return;
+
+			/*
+			 * The forget flag here is critical because if
+			 * we are journaling (and not doing data
+			 * journaling), we have to make sure a revoke
+			 * record is written to prevent the journal
+			 * replay from overwriting the (former)
+			 * indirect block if it gets reallocated as a
+			 * data block.  This must happen in the same
+			 * transaction where the data blocks are
+			 * actually freed.
+			 */
+			ext4_free_blocks(handle, inode, NULL, nr, 1,
+					 EXT4_FREE_BLOCKS_METADATA|
+					 EXT4_FREE_BLOCKS_FORGET);
+
+			if (parent_bh) {
+				/*
+				 * The block which we have just freed is
+				 * pointed to by an indirect block: journal it
+				 */
+				BUFFER_TRACE(parent_bh, "get_write_access");
+				if (!ext4_journal_get_write_access(handle,
+								   parent_bh)){
+					*p = 0;
+					BUFFER_TRACE(parent_bh,
+					"call ext4_handle_dirty_metadata");
+					ext4_handle_dirty_metadata(handle,
+								   inode,
+								   parent_bh);
+				}
+			}
+		}
+	} else {
+		/* We have reached the bottom of the tree. */
+		BUFFER_TRACE(parent_bh, "free data blocks");
+		ext4_free_data(handle, inode, parent_bh, first, last);
+	}
+}
+
+void ext4_ind_truncate(handle_t *handle, struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	__le32 *i_data = ei->i_data;
+	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+	ext4_lblk_t offsets[4];
+	Indirect chain[4];
+	Indirect *partial;
+	__le32 nr = 0;
+	int n = 0;
+	ext4_lblk_t last_block, max_block;
+	unsigned blocksize = inode->i_sb->s_blocksize;
+
+	last_block = (inode->i_size + blocksize-1)
+					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
+	max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
+					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
+
+	if (last_block != max_block) {
+		n = ext4_block_to_path(inode, last_block, offsets, NULL);
+		if (n == 0)
+			return;
+	}
+
+	ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
+
+	/*
+	 * The orphan list entry will now protect us from any crash which
+	 * occurs before the truncate completes, so it is now safe to propagate
+	 * the new, shorter inode size (held for now in i_size) into the
+	 * on-disk inode. We do this via i_disksize, which is the value which
+	 * ext4 *really* writes onto the disk inode.
+	 */
+	ei->i_disksize = inode->i_size;
+
+	if (last_block == max_block) {
+		/*
+		 * It is unnecessary to free any data blocks if last_block is
+		 * equal to the indirect block limit.
+		 */
+		return;
+	} else if (n == 1) {		/* direct blocks */
+		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
+			       i_data + EXT4_NDIR_BLOCKS);
+		goto do_indirects;
+	}
+
+	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
+	/* Kill the top of shared branch (not detached) */
+	if (nr) {
+		if (partial == chain) {
+			/* Shared branch grows from the inode */
+			ext4_free_branches(handle, inode, NULL,
+					   &nr, &nr+1, (chain+n-1) - partial);
+			*partial->p = 0;
+			/*
+			 * We mark the inode dirty prior to restart,
+			 * and prior to stop.  No need for it here.
+			 */
+		} else {
+			/* Shared branch grows from an indirect block */
+			BUFFER_TRACE(partial->bh, "get_write_access");
+			ext4_free_branches(handle, inode, partial->bh,
+					partial->p,
+					partial->p+1, (chain+n-1) - partial);
+		}
+	}
+	/* Clear the ends of indirect blocks on the shared branch */
+	while (partial > chain) {
+		ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
+				   (__le32*)partial->bh->b_data+addr_per_block,
+				   (chain+n-1) - partial);
+		BUFFER_TRACE(partial->bh, "call brelse");
+		brelse(partial->bh);
+		partial--;
+	}
+do_indirects:
+	/* Kill the remaining (whole) subtrees */
+	switch (offsets[0]) {
+	default:
+		nr = i_data[EXT4_IND_BLOCK];
+		if (nr) {
+			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
+			i_data[EXT4_IND_BLOCK] = 0;
+		}
+		fallthrough;
+	case EXT4_IND_BLOCK:
+		nr = i_data[EXT4_DIND_BLOCK];
+		if (nr) {
+			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
+			i_data[EXT4_DIND_BLOCK] = 0;
+		}
+		fallthrough;
+	case EXT4_DIND_BLOCK:
+		nr = i_data[EXT4_TIND_BLOCK];
+		if (nr) {
+			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
+			i_data[EXT4_TIND_BLOCK] = 0;
+		}
+		fallthrough;
+	case EXT4_TIND_BLOCK:
+		;
+	}
+}
+
+/**
+ *	ext4_ind_remove_space - remove space from the range
+ *	@handle: JBD handle for this transaction
+ *	@inode:	inode we are dealing with
+ *	@start:	First block to remove
+ *	@end:	One block after the last block to remove (exclusive)
+ *
+ *	Free the blocks in the defined range (end is exclusive endpoint of
+ *	range). This is used by ext4_punch_hole().
+ */
+int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
+			  ext4_lblk_t start, ext4_lblk_t end)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	__le32 *i_data = ei->i_data;
+	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+	ext4_lblk_t offsets[4], offsets2[4];
+	Indirect chain[4], chain2[4];
+	Indirect *partial, *partial2;
+	Indirect *p = NULL, *p2 = NULL;
+	ext4_lblk_t max_block;
+	__le32 nr = 0, nr2 = 0;
+	int n = 0, n2 = 0;
+	unsigned blocksize = inode->i_sb->s_blocksize;
+
+	max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
+					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
+	if (end >= max_block)
+		end = max_block;
+	if ((start >= end) || (start > max_block))
+		return 0;
+
+	n = ext4_block_to_path(inode, start, offsets, NULL);
+	n2 = ext4_block_to_path(inode, end, offsets2, NULL);
+
+	BUG_ON(n > n2);
+
+	if ((n == 1) && (n == n2)) {
+		/* We're punching only within direct block range */
+		ext4_free_data(handle, inode, NULL, i_data + offsets[0],
+			       i_data + offsets2[0]);
+		return 0;
+	} else if (n2 > n) {
+		/*
+		 * Start and end are on a different levels so we're going to
+		 * free partial block at start, and partial block at end of
+		 * the range. If there are some levels in between then
+		 * do_indirects label will take care of that.
+		 */
+
+		if (n == 1) {
+			/*
+			 * Start is at the direct block level, free
+			 * everything to the end of the level.
+			 */
+			ext4_free_data(handle, inode, NULL, i_data + offsets[0],
+				       i_data + EXT4_NDIR_BLOCKS);
+			goto end_range;
+		}
+
+
+		partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
+		if (nr) {
+			if (partial == chain) {
+				/* Shared branch grows from the inode */
+				ext4_free_branches(handle, inode, NULL,
+					   &nr, &nr+1, (chain+n-1) - partial);
+				*partial->p = 0;
+			} else {
+				/* Shared branch grows from an indirect block */
+				BUFFER_TRACE(partial->bh, "get_write_access");
+				ext4_free_branches(handle, inode, partial->bh,
+					partial->p,
+					partial->p+1, (chain+n-1) - partial);
+			}
+		}
+
+		/*
+		 * Clear the ends of indirect blocks on the shared branch
+		 * at the start of the range
+		 */
+		while (partial > chain) {
+			ext4_free_branches(handle, inode, partial->bh,
+				partial->p + 1,
+				(__le32 *)partial->bh->b_data+addr_per_block,
+				(chain+n-1) - partial);
+			partial--;
+		}
+
+end_range:
+		partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
+		if (nr2) {
+			if (partial2 == chain2) {
+				/*
+				 * Remember, end is exclusive so here we're at
+				 * the start of the next level we're not going
+				 * to free. Everything was covered by the start
+				 * of the range.
+				 */
+				goto do_indirects;
+			}
+		} else {
+			/*
+			 * ext4_find_shared returns Indirect structure which
+			 * points to the last element which should not be
+			 * removed by truncate. But this is end of the range
+			 * in punch_hole so we need to point to the next element
+			 */
+			partial2->p++;
+		}
+
+		/*
+		 * Clear the ends of indirect blocks on the shared branch
+		 * at the end of the range
+		 */
+		while (partial2 > chain2) {
+			ext4_free_branches(handle, inode, partial2->bh,
+					   (__le32 *)partial2->bh->b_data,
+					   partial2->p,
+					   (chain2+n2-1) - partial2);
+			partial2--;
+		}
+		goto do_indirects;
+	}
+
+	/* Punch happened within the same level (n == n2) */
+	partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
+	partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
+
+	/* Free top, but only if partial2 isn't its subtree. */
+	if (nr) {
+		int level = min(partial - chain, partial2 - chain2);
+		int i;
+		int subtree = 1;
+
+		for (i = 0; i <= level; i++) {
+			if (offsets[i] != offsets2[i]) {
+				subtree = 0;
+				break;
+			}
+		}
+
+		if (!subtree) {
+			if (partial == chain) {
+				/* Shared branch grows from the inode */
+				ext4_free_branches(handle, inode, NULL,
+						   &nr, &nr+1,
+						   (chain+n-1) - partial);
+				*partial->p = 0;
+			} else {
+				/* Shared branch grows from an indirect block */
+				BUFFER_TRACE(partial->bh, "get_write_access");
+				ext4_free_branches(handle, inode, partial->bh,
+						   partial->p,
+						   partial->p+1,
+						   (chain+n-1) - partial);
+			}
+		}
+	}
+
+	if (!nr2) {
+		/*
+		 * ext4_find_shared returns Indirect structure which
+		 * points to the last element which should not be
+		 * removed by truncate. But this is end of the range
+		 * in punch_hole so we need to point to the next element
+		 */
+		partial2->p++;
+	}
+
+	while (partial > chain || partial2 > chain2) {
+		int depth = (chain+n-1) - partial;
+		int depth2 = (chain2+n2-1) - partial2;
+
+		if (partial > chain && partial2 > chain2 &&
+		    partial->bh->b_blocknr == partial2->bh->b_blocknr) {
+			/*
+			 * We've converged on the same block. Clear the range,
+			 * then we're done.
+			 */
+			ext4_free_branches(handle, inode, partial->bh,
+					   partial->p + 1,
+					   partial2->p,
+					   (chain+n-1) - partial);
+			goto cleanup;
+		}
+
+		/*
+		 * The start and end partial branches may not be at the same
+		 * level even though the punch happened within one level. So, we
+		 * give them a chance to arrive at the same level, then walk
+		 * them in step with each other until we converge on the same
+		 * block.
+		 */
+		if (partial > chain && depth <= depth2) {
+			ext4_free_branches(handle, inode, partial->bh,
+					   partial->p + 1,
+					   (__le32 *)partial->bh->b_data+addr_per_block,
+					   (chain+n-1) - partial);
+			partial--;
+		}
+		if (partial2 > chain2 && depth2 <= depth) {
+			ext4_free_branches(handle, inode, partial2->bh,
+					   (__le32 *)partial2->bh->b_data,
+					   partial2->p,
+					   (chain2+n2-1) - partial2);
+			partial2--;
+		}
+	}
+
+cleanup:
+	while (p && p > chain) {
+		BUFFER_TRACE(p->bh, "call brelse");
+		brelse(p->bh);
+		p--;
+	}
+	while (p2 && p2 > chain2) {
+		BUFFER_TRACE(p2->bh, "call brelse");
+		brelse(p2->bh);
+		p2--;
+	}
+	return 0;
+
+do_indirects:
+	/* Kill the remaining (whole) subtrees */
+	switch (offsets[0]) {
+	default:
+		if (++n >= n2)
+			break;
+		nr = i_data[EXT4_IND_BLOCK];
+		if (nr) {
+			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
+			i_data[EXT4_IND_BLOCK] = 0;
+		}
+		fallthrough;
+	case EXT4_IND_BLOCK:
+		if (++n >= n2)
+			break;
+		nr = i_data[EXT4_DIND_BLOCK];
+		if (nr) {
+			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
+			i_data[EXT4_DIND_BLOCK] = 0;
+		}
+		fallthrough;
+	case EXT4_DIND_BLOCK:
+		if (++n >= n2)
+			break;
+		nr = i_data[EXT4_TIND_BLOCK];
+		if (nr) {
+			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
+			i_data[EXT4_TIND_BLOCK] = 0;
+		}
+		fallthrough;
+	case EXT4_TIND_BLOCK:
+		;
+	}
+	goto cleanup;
+}
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
new file mode 100644
index 000000000..979935c07
--- /dev/null
+++ b/fs/ext4/inline.c
@@ -0,0 +1,2024 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (c) 2012 Taobao.
+ * Written by Tao Ma <boyu.mt@taobao.com>
+ */
+
+#include <linux/iomap.h>
+#include <linux/fiemap.h>
+#include <linux/iversion.h>
+
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+#include "truncate.h"
+
+#define EXT4_XATTR_SYSTEM_DATA	"data"
+#define EXT4_MIN_INLINE_DATA_SIZE	((sizeof(__le32) * EXT4_N_BLOCKS))
+#define EXT4_INLINE_DOTDOT_OFFSET	2
+#define EXT4_INLINE_DOTDOT_SIZE		4
+
+static int ext4_get_inline_size(struct inode *inode)
+{
+	if (EXT4_I(inode)->i_inline_off)
+		return EXT4_I(inode)->i_inline_size;
+
+	return 0;
+}
+
+static int get_max_inline_xattr_value_size(struct inode *inode,
+					   struct ext4_iloc *iloc)
+{
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_xattr_entry *entry;
+	struct ext4_inode *raw_inode;
+	void *end;
+	int free, min_offs;
+
+	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
+		return 0;
+
+	min_offs = EXT4_SB(inode->i_sb)->s_inode_size -
+			EXT4_GOOD_OLD_INODE_SIZE -
+			EXT4_I(inode)->i_extra_isize -
+			sizeof(struct ext4_xattr_ibody_header);
+
+	/*
+	 * We need to subtract another sizeof(__u32) since an in-inode xattr
+	 * needs an empty 4 bytes to indicate the gap between the xattr entry
+	 * and the name/value pair.
+	 */
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
+		return EXT4_XATTR_SIZE(min_offs -
+			EXT4_XATTR_LEN(strlen(EXT4_XATTR_SYSTEM_DATA)) -
+			EXT4_XATTR_ROUND - sizeof(__u32));
+
+	raw_inode = ext4_raw_inode(iloc);
+	header = IHDR(inode, raw_inode);
+	entry = IFIRST(header);
+	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+
+	/* Compute min_offs. */
+	while (!IS_LAST_ENTRY(entry)) {
+		void *next = EXT4_XATTR_NEXT(entry);
+
+		if (next >= end) {
+			EXT4_ERROR_INODE(inode,
+					 "corrupt xattr in inline inode");
+			return 0;
+		}
+		if (!entry->e_value_inum && entry->e_value_size) {
+			size_t offs = le16_to_cpu(entry->e_value_offs);
+			if (offs < min_offs)
+				min_offs = offs;
+		}
+		entry = next;
+	}
+	free = min_offs -
+		((void *)entry - (void *)IFIRST(header)) - sizeof(__u32);
+
+	if (EXT4_I(inode)->i_inline_off) {
+		entry = (struct ext4_xattr_entry *)
+			((void *)raw_inode + EXT4_I(inode)->i_inline_off);
+
+		free += EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
+		goto out;
+	}
+
+	free -= EXT4_XATTR_LEN(strlen(EXT4_XATTR_SYSTEM_DATA));
+
+	if (free > EXT4_XATTR_ROUND)
+		free = EXT4_XATTR_SIZE(free - EXT4_XATTR_ROUND);
+	else
+		free = 0;
+
+out:
+	return free;
+}
+
+/*
+ * Get the maximum size we now can store in an inode.
+ * If we can't find the space for a xattr entry, don't use the space
+ * of the extents since we have no space to indicate the inline data.
+ */
+int ext4_get_max_inline_size(struct inode *inode)
+{
+	int error, max_inline_size;
+	struct ext4_iloc iloc;
+
+	if (EXT4_I(inode)->i_extra_isize == 0)
+		return 0;
+
+	error = ext4_get_inode_loc(inode, &iloc);
+	if (error) {
+		ext4_error_inode_err(inode, __func__, __LINE__, 0, -error,
+				     "can't get inode location %lu",
+				     inode->i_ino);
+		return 0;
+	}
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	max_inline_size = get_max_inline_xattr_value_size(inode, &iloc);
+	up_read(&EXT4_I(inode)->xattr_sem);
+
+	brelse(iloc.bh);
+
+	if (!max_inline_size)
+		return 0;
+
+	return max_inline_size + EXT4_MIN_INLINE_DATA_SIZE;
+}
+
+/*
+ * this function does not take xattr_sem, which is OK because it is
+ * currently only used in a code path coming form ext4_iget, before
+ * the new inode has been unlocked
+ */
+int ext4_find_inline_data_nolock(struct inode *inode)
+{
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext4_xattr_info i = {
+		.name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_DATA,
+	};
+	int error;
+
+	if (EXT4_I(inode)->i_extra_isize == 0)
+		return 0;
+
+	error = ext4_get_inode_loc(inode, &is.iloc);
+	if (error)
+		return error;
+
+	error = ext4_xattr_ibody_find(inode, &i, &is);
+	if (error)
+		goto out;
+
+	if (!is.s.not_found) {
+		if (is.s.here->e_value_inum) {
+			EXT4_ERROR_INODE(inode, "inline data xattr refers "
+					 "to an external xattr inode");
+			error = -EFSCORRUPTED;
+			goto out;
+		}
+		EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
+					(void *)ext4_raw_inode(&is.iloc));
+		EXT4_I(inode)->i_inline_size = EXT4_MIN_INLINE_DATA_SIZE +
+				le32_to_cpu(is.s.here->e_value_size);
+	}
+out:
+	brelse(is.iloc.bh);
+	return error;
+}
+
+static int ext4_read_inline_data(struct inode *inode, void *buffer,
+				 unsigned int len,
+				 struct ext4_iloc *iloc)
+{
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_ibody_header *header;
+	int cp_len = 0;
+	struct ext4_inode *raw_inode;
+
+	if (!len)
+		return 0;
+
+	BUG_ON(len > EXT4_I(inode)->i_inline_size);
+
+	cp_len = len < EXT4_MIN_INLINE_DATA_SIZE ?
+			len : EXT4_MIN_INLINE_DATA_SIZE;
+
+	raw_inode = ext4_raw_inode(iloc);
+	memcpy(buffer, (void *)(raw_inode->i_block), cp_len);
+
+	len -= cp_len;
+	buffer += cp_len;
+
+	if (!len)
+		goto out;
+
+	header = IHDR(inode, raw_inode);
+	entry = (struct ext4_xattr_entry *)((void *)raw_inode +
+					    EXT4_I(inode)->i_inline_off);
+	len = min_t(unsigned int, len,
+		    (unsigned int)le32_to_cpu(entry->e_value_size));
+
+	memcpy(buffer,
+	       (void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs), len);
+	cp_len += len;
+
+out:
+	return cp_len;
+}
+
+/*
+ * write the buffer to the inline inode.
+ * If 'create' is set, we don't need to do the extra copy in the xattr
+ * value since it is already handled by ext4_xattr_ibody_set.
+ * That saves us one memcpy.
+ */
+static void ext4_write_inline_data(struct inode *inode, struct ext4_iloc *iloc,
+				   void *buffer, loff_t pos, unsigned int len)
+{
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_inode *raw_inode;
+	int cp_len = 0;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return;
+
+	BUG_ON(!EXT4_I(inode)->i_inline_off);
+	BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);
+
+	raw_inode = ext4_raw_inode(iloc);
+	buffer += pos;
+
+	if (pos < EXT4_MIN_INLINE_DATA_SIZE) {
+		cp_len = pos + len > EXT4_MIN_INLINE_DATA_SIZE ?
+			 EXT4_MIN_INLINE_DATA_SIZE - pos : len;
+		memcpy((void *)raw_inode->i_block + pos, buffer, cp_len);
+
+		len -= cp_len;
+		buffer += cp_len;
+		pos += cp_len;
+	}
+
+	if (!len)
+		return;
+
+	pos -= EXT4_MIN_INLINE_DATA_SIZE;
+	header = IHDR(inode, raw_inode);
+	entry = (struct ext4_xattr_entry *)((void *)raw_inode +
+					    EXT4_I(inode)->i_inline_off);
+
+	memcpy((void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs) + pos,
+	       buffer, len);
+}
+
+static int ext4_create_inline_data(handle_t *handle,
+				   struct inode *inode, unsigned len)
+{
+	int error;
+	void *value = NULL;
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext4_xattr_info i = {
+		.name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_DATA,
+	};
+
+	error = ext4_get_inode_loc(inode, &is.iloc);
+	if (error)
+		return error;
+
+	BUFFER_TRACE(is.iloc.bh, "get_write_access");
+	error = ext4_journal_get_write_access(handle, is.iloc.bh);
+	if (error)
+		goto out;
+
+	if (len > EXT4_MIN_INLINE_DATA_SIZE) {
+		value = EXT4_ZERO_XATTR_VALUE;
+		len -= EXT4_MIN_INLINE_DATA_SIZE;
+	} else {
+		value = "";
+		len = 0;
+	}
+
+	/* Insert the xttr entry. */
+	i.value = value;
+	i.value_len = len;
+
+	error = ext4_xattr_ibody_find(inode, &i, &is);
+	if (error)
+		goto out;
+
+	BUG_ON(!is.s.not_found);
+
+	error = ext4_xattr_ibody_set(handle, inode, &i, &is);
+	if (error) {
+		if (error == -ENOSPC)
+			ext4_clear_inode_state(inode,
+					       EXT4_STATE_MAY_INLINE_DATA);
+		goto out;
+	}
+
+	memset((void *)ext4_raw_inode(&is.iloc)->i_block,
+		0, EXT4_MIN_INLINE_DATA_SIZE);
+
+	EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
+				      (void *)ext4_raw_inode(&is.iloc));
+	EXT4_I(inode)->i_inline_size = len + EXT4_MIN_INLINE_DATA_SIZE;
+	ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
+	ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA);
+	get_bh(is.iloc.bh);
+	error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
+
+out:
+	brelse(is.iloc.bh);
+	return error;
+}
+
+static int ext4_update_inline_data(handle_t *handle, struct inode *inode,
+				   unsigned int len)
+{
+	int error;
+	void *value = NULL;
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext4_xattr_info i = {
+		.name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_DATA,
+	};
+
+	/* If the old space is ok, write the data directly. */
+	if (len <= EXT4_I(inode)->i_inline_size)
+		return 0;
+
+	error = ext4_get_inode_loc(inode, &is.iloc);
+	if (error)
+		return error;
+
+	error = ext4_xattr_ibody_find(inode, &i, &is);
+	if (error)
+		goto out;
+
+	BUG_ON(is.s.not_found);
+
+	len -= EXT4_MIN_INLINE_DATA_SIZE;
+	value = kzalloc(len, GFP_NOFS);
+	if (!value) {
+		error = -ENOMEM;
+		goto out;
+	}
+
+	error = ext4_xattr_ibody_get(inode, i.name_index, i.name,
+				     value, len);
+	if (error < 0)
+		goto out;
+
+	BUFFER_TRACE(is.iloc.bh, "get_write_access");
+	error = ext4_journal_get_write_access(handle, is.iloc.bh);
+	if (error)
+		goto out;
+
+	/* Update the xattr entry. */
+	i.value = value;
+	i.value_len = len;
+
+	error = ext4_xattr_ibody_set(handle, inode, &i, &is);
+	if (error)
+		goto out;
+
+	EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
+				      (void *)ext4_raw_inode(&is.iloc));
+	EXT4_I(inode)->i_inline_size = EXT4_MIN_INLINE_DATA_SIZE +
+				le32_to_cpu(is.s.here->e_value_size);
+	ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+	get_bh(is.iloc.bh);
+	error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
+
+out:
+	kfree(value);
+	brelse(is.iloc.bh);
+	return error;
+}
+
+static int ext4_prepare_inline_data(handle_t *handle, struct inode *inode,
+				    unsigned int len)
+{
+	int ret, size, no_expand;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))
+		return -ENOSPC;
+
+	size = ext4_get_max_inline_size(inode);
+	if (size < len)
+		return -ENOSPC;
+
+	ext4_write_lock_xattr(inode, &no_expand);
+
+	if (ei->i_inline_off)
+		ret = ext4_update_inline_data(handle, inode, len);
+	else
+		ret = ext4_create_inline_data(handle, inode, len);
+
+	ext4_write_unlock_xattr(inode, &no_expand);
+	return ret;
+}
+
+static int ext4_destroy_inline_data_nolock(handle_t *handle,
+					   struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = 0, },
+	};
+	struct ext4_xattr_info i = {
+		.name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_DATA,
+		.value = NULL,
+		.value_len = 0,
+	};
+	int error;
+
+	if (!ei->i_inline_off)
+		return 0;
+
+	error = ext4_get_inode_loc(inode, &is.iloc);
+	if (error)
+		return error;
+
+	error = ext4_xattr_ibody_find(inode, &i, &is);
+	if (error)
+		goto out;
+
+	BUFFER_TRACE(is.iloc.bh, "get_write_access");
+	error = ext4_journal_get_write_access(handle, is.iloc.bh);
+	if (error)
+		goto out;
+
+	error = ext4_xattr_ibody_set(handle, inode, &i, &is);
+	if (error)
+		goto out;
+
+	memset((void *)ext4_raw_inode(&is.iloc)->i_block,
+		0, EXT4_MIN_INLINE_DATA_SIZE);
+	memset(ei->i_data, 0, EXT4_MIN_INLINE_DATA_SIZE);
+
+	if (ext4_has_feature_extents(inode->i_sb)) {
+		if (S_ISDIR(inode->i_mode) ||
+		    S_ISREG(inode->i_mode) || S_ISLNK(inode->i_mode)) {
+			ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
+			ext4_ext_tree_init(handle, inode);
+		}
+	}
+	ext4_clear_inode_flag(inode, EXT4_INODE_INLINE_DATA);
+
+	get_bh(is.iloc.bh);
+	error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
+
+	EXT4_I(inode)->i_inline_off = 0;
+	EXT4_I(inode)->i_inline_size = 0;
+	ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+out:
+	brelse(is.iloc.bh);
+	if (error == -ENODATA)
+		error = 0;
+	return error;
+}
+
+static int ext4_read_inline_page(struct inode *inode, struct page *page)
+{
+	void *kaddr;
+	int ret = 0;
+	size_t len;
+	struct ext4_iloc iloc;
+
+	BUG_ON(!PageLocked(page));
+	BUG_ON(!ext4_has_inline_data(inode));
+	BUG_ON(page->index);
+
+	if (!EXT4_I(inode)->i_inline_off) {
+		ext4_warning(inode->i_sb, "inode %lu doesn't have inline data.",
+			     inode->i_ino);
+		goto out;
+	}
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		goto out;
+
+	len = min_t(size_t, ext4_get_inline_size(inode), i_size_read(inode));
+	kaddr = kmap_atomic(page);
+	ret = ext4_read_inline_data(inode, kaddr, len, &iloc);
+	flush_dcache_page(page);
+	kunmap_atomic(kaddr);
+	zero_user_segment(page, len, PAGE_SIZE);
+	SetPageUptodate(page);
+	brelse(iloc.bh);
+
+out:
+	return ret;
+}
+
+int ext4_readpage_inline(struct inode *inode, struct page *page)
+{
+	int ret = 0;
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	if (!ext4_has_inline_data(inode)) {
+		up_read(&EXT4_I(inode)->xattr_sem);
+		return -EAGAIN;
+	}
+
+	/*
+	 * Current inline data can only exist in the 1st page,
+	 * So for all the other pages, just set them uptodate.
+	 */
+	if (!page->index)
+		ret = ext4_read_inline_page(inode, page);
+	else if (!PageUptodate(page)) {
+		zero_user_segment(page, 0, PAGE_SIZE);
+		SetPageUptodate(page);
+	}
+
+	up_read(&EXT4_I(inode)->xattr_sem);
+
+	unlock_page(page);
+	return ret >= 0 ? 0 : ret;
+}
+
+static int ext4_convert_inline_data_to_extent(struct address_space *mapping,
+					      struct inode *inode,
+					      unsigned flags)
+{
+	int ret, needed_blocks, no_expand;
+	handle_t *handle = NULL;
+	int retries = 0, sem_held = 0;
+	struct page *page = NULL;
+	unsigned from, to;
+	struct ext4_iloc iloc;
+
+	if (!ext4_has_inline_data(inode)) {
+		/*
+		 * clear the flag so that no new write
+		 * will trap here again.
+		 */
+		ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+		return 0;
+	}
+
+	needed_blocks = ext4_writepage_trans_blocks(inode);
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+retry:
+	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		handle = NULL;
+		goto out;
+	}
+
+	/* We cannot recurse into the filesystem as the transaction is already
+	 * started */
+	flags |= AOP_FLAG_NOFS;
+
+	page = grab_cache_page_write_begin(mapping, 0, flags);
+	if (!page) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ext4_write_lock_xattr(inode, &no_expand);
+	sem_held = 1;
+	/* If some one has already done this for us, just exit. */
+	if (!ext4_has_inline_data(inode)) {
+		ret = 0;
+		goto out;
+	}
+
+	from = 0;
+	to = ext4_get_inline_size(inode);
+	if (!PageUptodate(page)) {
+		ret = ext4_read_inline_page(inode, page);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = ext4_destroy_inline_data_nolock(handle, inode);
+	if (ret)
+		goto out;
+
+	if (ext4_should_dioread_nolock(inode)) {
+		ret = __block_write_begin(page, from, to,
+					  ext4_get_block_unwritten);
+	} else
+		ret = __block_write_begin(page, from, to, ext4_get_block);
+
+	if (!ret && ext4_should_journal_data(inode)) {
+		ret = ext4_walk_page_buffers(handle, page_buffers(page),
+					     from, to, NULL,
+					     do_journal_get_write_access);
+	}
+
+	if (ret) {
+		unlock_page(page);
+		put_page(page);
+		page = NULL;
+		ext4_orphan_add(handle, inode);
+		ext4_write_unlock_xattr(inode, &no_expand);
+		sem_held = 0;
+		ext4_journal_stop(handle);
+		handle = NULL;
+		ext4_truncate_failed_write(inode);
+		/*
+		 * If truncate failed early the inode might
+		 * still be on the orphan list; we need to
+		 * make sure the inode is removed from the
+		 * orphan list in that case.
+		 */
+		if (inode->i_nlink)
+			ext4_orphan_del(NULL, inode);
+	}
+
+	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+
+	if (page)
+		block_commit_write(page, from, to);
+out:
+	if (page) {
+		unlock_page(page);
+		put_page(page);
+	}
+	if (sem_held)
+		ext4_write_unlock_xattr(inode, &no_expand);
+	if (handle)
+		ext4_journal_stop(handle);
+	brelse(iloc.bh);
+	return ret;
+}
+
+/*
+ * Try to write data in the inode.
+ * If the inode has inline data, check whether the new write can be
+ * in the inode also. If not, create the page the handle, move the data
+ * to the page make it update and let the later codes create extent for it.
+ */
+int ext4_try_to_write_inline_data(struct address_space *mapping,
+				  struct inode *inode,
+				  loff_t pos, unsigned len,
+				  unsigned flags,
+				  struct page **pagep)
+{
+	int ret;
+	handle_t *handle;
+	struct page *page;
+	struct ext4_iloc iloc;
+
+	if (pos + len > ext4_get_max_inline_size(inode))
+		goto convert;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+	/*
+	 * The possible write could happen in the inode,
+	 * so try to reserve the space in inode first.
+	 */
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		handle = NULL;
+		goto out;
+	}
+
+	ret = ext4_prepare_inline_data(handle, inode, pos + len);
+	if (ret && ret != -ENOSPC)
+		goto out;
+
+	/* We don't have space in inline inode, so convert it to extent. */
+	if (ret == -ENOSPC) {
+		ext4_journal_stop(handle);
+		brelse(iloc.bh);
+		goto convert;
+	}
+
+	ret = ext4_journal_get_write_access(handle, iloc.bh);
+	if (ret)
+		goto out;
+
+	flags |= AOP_FLAG_NOFS;
+
+	page = grab_cache_page_write_begin(mapping, 0, flags);
+	if (!page) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	*pagep = page;
+	down_read(&EXT4_I(inode)->xattr_sem);
+	if (!ext4_has_inline_data(inode)) {
+		ret = 0;
+		unlock_page(page);
+		put_page(page);
+		goto out_up_read;
+	}
+
+	if (!PageUptodate(page)) {
+		ret = ext4_read_inline_page(inode, page);
+		if (ret < 0) {
+			unlock_page(page);
+			put_page(page);
+			goto out_up_read;
+		}
+	}
+
+	ret = 1;
+	handle = NULL;
+out_up_read:
+	up_read(&EXT4_I(inode)->xattr_sem);
+out:
+	if (handle && (ret != 1))
+		ext4_journal_stop(handle);
+	brelse(iloc.bh);
+	return ret;
+convert:
+	return ext4_convert_inline_data_to_extent(mapping,
+						  inode, flags);
+}
+
+int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len,
+			       unsigned copied, struct page *page)
+{
+	int ret, no_expand;
+	void *kaddr;
+	struct ext4_iloc iloc;
+
+	if (unlikely(copied < len) && !PageUptodate(page))
+		return 0;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret) {
+		ext4_std_error(inode->i_sb, ret);
+		return ret;
+	}
+
+	ext4_write_lock_xattr(inode, &no_expand);
+	BUG_ON(!ext4_has_inline_data(inode));
+
+	/*
+	 * ei->i_inline_off may have changed since ext4_write_begin()
+	 * called ext4_try_to_write_inline_data()
+	 */
+	(void) ext4_find_inline_data_nolock(inode);
+
+	kaddr = kmap_atomic(page);
+	ext4_write_inline_data(inode, &iloc, kaddr, pos, copied);
+	kunmap_atomic(kaddr);
+	SetPageUptodate(page);
+	/* clear page dirty so that writepages wouldn't work for us. */
+	ClearPageDirty(page);
+
+	ext4_write_unlock_xattr(inode, &no_expand);
+	brelse(iloc.bh);
+	mark_inode_dirty(inode);
+
+	return copied;
+}
+
+struct buffer_head *
+ext4_journalled_write_inline_data(struct inode *inode,
+				  unsigned len,
+				  struct page *page)
+{
+	int ret, no_expand;
+	void *kaddr;
+	struct ext4_iloc iloc;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret) {
+		ext4_std_error(inode->i_sb, ret);
+		return NULL;
+	}
+
+	ext4_write_lock_xattr(inode, &no_expand);
+	kaddr = kmap_atomic(page);
+	ext4_write_inline_data(inode, &iloc, kaddr, 0, len);
+	kunmap_atomic(kaddr);
+	ext4_write_unlock_xattr(inode, &no_expand);
+
+	return iloc.bh;
+}
+
+/*
+ * Try to make the page cache and handle ready for the inline data case.
+ * We can call this function in 2 cases:
+ * 1. The inode is created and the first write exceeds inline size. We can
+ *    clear the inode state safely.
+ * 2. The inode has inline data, then we need to read the data, make it
+ *    update and dirty so that ext4_da_writepages can handle it. We don't
+ *    need to start the journal since the file's metadata isn't changed now.
+ */
+static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
+						 struct inode *inode,
+						 unsigned flags,
+						 void **fsdata)
+{
+	int ret = 0, inline_size;
+	struct page *page;
+
+	page = grab_cache_page_write_begin(mapping, 0, flags);
+	if (!page)
+		return -ENOMEM;
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	if (!ext4_has_inline_data(inode)) {
+		ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+		goto out;
+	}
+
+	inline_size = ext4_get_inline_size(inode);
+
+	if (!PageUptodate(page)) {
+		ret = ext4_read_inline_page(inode, page);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = __block_write_begin(page, 0, inline_size,
+				  ext4_da_get_block_prep);
+	if (ret) {
+		up_read(&EXT4_I(inode)->xattr_sem);
+		unlock_page(page);
+		put_page(page);
+		ext4_truncate_failed_write(inode);
+		return ret;
+	}
+
+	SetPageDirty(page);
+	SetPageUptodate(page);
+	ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+	*fsdata = (void *)CONVERT_INLINE_DATA;
+
+out:
+	up_read(&EXT4_I(inode)->xattr_sem);
+	if (page) {
+		unlock_page(page);
+		put_page(page);
+	}
+	return ret;
+}
+
+/*
+ * Prepare the write for the inline data.
+ * If the data can be written into the inode, we just read
+ * the page and make it uptodate, and start the journal.
+ * Otherwise read the page, makes it dirty so that it can be
+ * handle in writepages(the i_disksize update is left to the
+ * normal ext4_da_write_end).
+ */
+int ext4_da_write_inline_data_begin(struct address_space *mapping,
+				    struct inode *inode,
+				    loff_t pos, unsigned len,
+				    unsigned flags,
+				    struct page **pagep,
+				    void **fsdata)
+{
+	int ret, inline_size;
+	handle_t *handle;
+	struct page *page;
+	struct ext4_iloc iloc;
+	int retries = 0;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+retry_journal:
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out;
+	}
+
+	inline_size = ext4_get_max_inline_size(inode);
+
+	ret = -ENOSPC;
+	if (inline_size >= pos + len) {
+		ret = ext4_prepare_inline_data(handle, inode, pos + len);
+		if (ret && ret != -ENOSPC)
+			goto out_journal;
+	}
+
+	/*
+	 * We cannot recurse into the filesystem as the transaction
+	 * is already started.
+	 */
+	flags |= AOP_FLAG_NOFS;
+
+	if (ret == -ENOSPC) {
+		ext4_journal_stop(handle);
+		ret = ext4_da_convert_inline_data_to_extent(mapping,
+							    inode,
+							    flags,
+							    fsdata);
+		if (ret == -ENOSPC &&
+		    ext4_should_retry_alloc(inode->i_sb, &retries))
+			goto retry_journal;
+		goto out;
+	}
+
+	page = grab_cache_page_write_begin(mapping, 0, flags);
+	if (!page) {
+		ret = -ENOMEM;
+		goto out_journal;
+	}
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	if (!ext4_has_inline_data(inode)) {
+		ret = 0;
+		goto out_release_page;
+	}
+
+	if (!PageUptodate(page)) {
+		ret = ext4_read_inline_page(inode, page);
+		if (ret < 0)
+			goto out_release_page;
+	}
+	ret = ext4_journal_get_write_access(handle, iloc.bh);
+	if (ret)
+		goto out_release_page;
+
+	up_read(&EXT4_I(inode)->xattr_sem);
+	*pagep = page;
+	brelse(iloc.bh);
+	return 1;
+out_release_page:
+	up_read(&EXT4_I(inode)->xattr_sem);
+	unlock_page(page);
+	put_page(page);
+out_journal:
+	ext4_journal_stop(handle);
+out:
+	brelse(iloc.bh);
+	return ret;
+}
+
+int ext4_da_write_inline_data_end(struct inode *inode, loff_t pos,
+				  unsigned len, unsigned copied,
+				  struct page *page)
+{
+	int ret;
+
+	ret = ext4_write_inline_data_end(inode, pos, len, copied, page);
+	if (ret < 0) {
+		unlock_page(page);
+		put_page(page);
+		return ret;
+	}
+	copied = ret;
+
+	/*
+	 * No need to use i_size_read() here, the i_size
+	 * cannot change under us because we hold i_mutex.
+	 *
+	 * But it's important to update i_size while still holding page lock:
+	 * page writeout could otherwise come in and zero beyond i_size.
+	 */
+	if (pos+copied > inode->i_size)
+		i_size_write(inode, pos+copied);
+	unlock_page(page);
+	put_page(page);
+
+	/*
+	 * Don't mark the inode dirty under page lock. First, it unnecessarily
+	 * makes the holding time of page lock longer. Second, it forces lock
+	 * ordering of page lock and transaction start for journaling
+	 * filesystems.
+	 */
+	mark_inode_dirty(inode);
+
+	return copied;
+}
+
+#ifdef INLINE_DIR_DEBUG
+void ext4_show_inline_dir(struct inode *dir, struct buffer_head *bh,
+			  void *inline_start, int inline_size)
+{
+	int offset;
+	unsigned short de_len;
+	struct ext4_dir_entry_2 *de = inline_start;
+	void *dlimit = inline_start + inline_size;
+
+	trace_printk("inode %lu\n", dir->i_ino);
+	offset = 0;
+	while ((void *)de < dlimit) {
+		de_len = ext4_rec_len_from_disk(de->rec_len, inline_size);
+		trace_printk("de: off %u rlen %u name %.*s nlen %u ino %u\n",
+			     offset, de_len, de->name_len, de->name,
+			     de->name_len, le32_to_cpu(de->inode));
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 inline_start, inline_size, offset))
+			BUG();
+
+		offset += de_len;
+		de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
+	}
+}
+#else
+#define ext4_show_inline_dir(dir, bh, inline_start, inline_size)
+#endif
+
+/*
+ * Add a new entry into a inline dir.
+ * It will return -ENOSPC if no space is available, and -EIO
+ * and -EEXIST if directory entry already exists.
+ */
+static int ext4_add_dirent_to_inline(handle_t *handle,
+				     struct ext4_filename *fname,
+				     struct inode *dir,
+				     struct inode *inode,
+				     struct ext4_iloc *iloc,
+				     void *inline_start, int inline_size)
+{
+	int		err;
+	struct ext4_dir_entry_2 *de;
+
+	err = ext4_find_dest_de(dir, inode, iloc->bh, inline_start,
+				inline_size, fname, &de);
+	if (err)
+		return err;
+
+	BUFFER_TRACE(iloc->bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, iloc->bh);
+	if (err)
+		return err;
+	ext4_insert_dentry(inode, de, inline_size, fname);
+
+	ext4_show_inline_dir(dir, iloc->bh, inline_start, inline_size);
+
+	/*
+	 * XXX shouldn't update any times until successful
+	 * completion of syscall, but too many callers depend
+	 * on this.
+	 *
+	 * XXX similarly, too many callers depend on
+	 * ext4_new_inode() setting the times, but error
+	 * recovery deletes the inode, so the worst that can
+	 * happen is that the times are slightly out of date
+	 * and/or different from the directory change time.
+	 */
+	dir->i_mtime = dir->i_ctime = current_time(dir);
+	ext4_update_dx_flag(dir);
+	inode_inc_iversion(dir);
+	return 1;
+}
+
+static void *ext4_get_inline_xattr_pos(struct inode *inode,
+				       struct ext4_iloc *iloc)
+{
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_ibody_header *header;
+
+	BUG_ON(!EXT4_I(inode)->i_inline_off);
+
+	header = IHDR(inode, ext4_raw_inode(iloc));
+	entry = (struct ext4_xattr_entry *)((void *)ext4_raw_inode(iloc) +
+					    EXT4_I(inode)->i_inline_off);
+
+	return (void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs);
+}
+
+/* Set the final de to cover the whole block. */
+static void ext4_update_final_de(void *de_buf, int old_size, int new_size)
+{
+	struct ext4_dir_entry_2 *de, *prev_de;
+	void *limit;
+	int de_len;
+
+	de = (struct ext4_dir_entry_2 *)de_buf;
+	if (old_size) {
+		limit = de_buf + old_size;
+		do {
+			prev_de = de;
+			de_len = ext4_rec_len_from_disk(de->rec_len, old_size);
+			de_buf += de_len;
+			de = (struct ext4_dir_entry_2 *)de_buf;
+		} while (de_buf < limit);
+
+		prev_de->rec_len = ext4_rec_len_to_disk(de_len + new_size -
+							old_size, new_size);
+	} else {
+		/* this is just created, so create an empty entry. */
+		de->inode = 0;
+		de->rec_len = ext4_rec_len_to_disk(new_size, new_size);
+	}
+}
+
+static int ext4_update_inline_dir(handle_t *handle, struct inode *dir,
+				  struct ext4_iloc *iloc)
+{
+	int ret;
+	int old_size = EXT4_I(dir)->i_inline_size - EXT4_MIN_INLINE_DATA_SIZE;
+	int new_size = get_max_inline_xattr_value_size(dir, iloc);
+
+	if (new_size - old_size <= EXT4_DIR_REC_LEN(1))
+		return -ENOSPC;
+
+	ret = ext4_update_inline_data(handle, dir,
+				      new_size + EXT4_MIN_INLINE_DATA_SIZE);
+	if (ret)
+		return ret;
+
+	ext4_update_final_de(ext4_get_inline_xattr_pos(dir, iloc), old_size,
+			     EXT4_I(dir)->i_inline_size -
+						EXT4_MIN_INLINE_DATA_SIZE);
+	dir->i_size = EXT4_I(dir)->i_disksize = EXT4_I(dir)->i_inline_size;
+	return 0;
+}
+
+static void ext4_restore_inline_data(handle_t *handle, struct inode *inode,
+				     struct ext4_iloc *iloc,
+				     void *buf, int inline_size)
+{
+	int ret;
+
+	ret = ext4_create_inline_data(handle, inode, inline_size);
+	if (ret) {
+		ext4_msg(inode->i_sb, KERN_EMERG,
+			"error restoring inline_data for inode -- potential data loss! (inode %lu, error %d)",
+			inode->i_ino, ret);
+		return;
+	}
+	ext4_write_inline_data(inode, iloc, buf, 0, inline_size);
+	ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+}
+
+static int ext4_finish_convert_inline_dir(handle_t *handle,
+					  struct inode *inode,
+					  struct buffer_head *dir_block,
+					  void *buf,
+					  int inline_size)
+{
+	int err, csum_size = 0, header_size = 0;
+	struct ext4_dir_entry_2 *de;
+	void *target = dir_block->b_data;
+
+	/*
+	 * First create "." and ".." and then copy the dir information
+	 * back to the block.
+	 */
+	de = (struct ext4_dir_entry_2 *)target;
+	de = ext4_init_dot_dotdot(inode, de,
+		inode->i_sb->s_blocksize, csum_size,
+		le32_to_cpu(((struct ext4_dir_entry_2 *)buf)->inode), 1);
+	header_size = (void *)de - target;
+
+	memcpy((void *)de, buf + EXT4_INLINE_DOTDOT_SIZE,
+		inline_size - EXT4_INLINE_DOTDOT_SIZE);
+
+	if (ext4_has_metadata_csum(inode->i_sb))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	inode->i_size = inode->i_sb->s_blocksize;
+	i_size_write(inode, inode->i_sb->s_blocksize);
+	EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
+	ext4_update_final_de(dir_block->b_data,
+			inline_size - EXT4_INLINE_DOTDOT_SIZE + header_size,
+			inode->i_sb->s_blocksize - csum_size);
+
+	if (csum_size)
+		ext4_initialize_dirent_tail(dir_block,
+					    inode->i_sb->s_blocksize);
+	set_buffer_uptodate(dir_block);
+	unlock_buffer(dir_block);
+	err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
+	if (err)
+		return err;
+	set_buffer_verified(dir_block);
+	return ext4_mark_inode_dirty(handle, inode);
+}
+
+static int ext4_convert_inline_data_nolock(handle_t *handle,
+					   struct inode *inode,
+					   struct ext4_iloc *iloc)
+{
+	int error;
+	void *buf = NULL;
+	struct buffer_head *data_bh = NULL;
+	struct ext4_map_blocks map;
+	int inline_size;
+
+	inline_size = ext4_get_inline_size(inode);
+	buf = kmalloc(inline_size, GFP_NOFS);
+	if (!buf) {
+		error = -ENOMEM;
+		goto out;
+	}
+
+	error = ext4_read_inline_data(inode, buf, inline_size, iloc);
+	if (error < 0)
+		goto out;
+
+	/*
+	 * Make sure the inline directory entries pass checks before we try to
+	 * convert them, so that we avoid touching stuff that needs fsck.
+	 */
+	if (S_ISDIR(inode->i_mode)) {
+		error = ext4_check_all_de(inode, iloc->bh,
+					buf + EXT4_INLINE_DOTDOT_SIZE,
+					inline_size - EXT4_INLINE_DOTDOT_SIZE);
+		if (error)
+			goto out;
+	}
+
+	error = ext4_destroy_inline_data_nolock(handle, inode);
+	if (error)
+		goto out;
+
+	map.m_lblk = 0;
+	map.m_len = 1;
+	map.m_flags = 0;
+	error = ext4_map_blocks(handle, inode, &map, EXT4_GET_BLOCKS_CREATE);
+	if (error < 0)
+		goto out_restore;
+	if (!(map.m_flags & EXT4_MAP_MAPPED)) {
+		error = -EIO;
+		goto out_restore;
+	}
+
+	data_bh = sb_getblk(inode->i_sb, map.m_pblk);
+	if (!data_bh) {
+		error = -ENOMEM;
+		goto out_restore;
+	}
+
+	lock_buffer(data_bh);
+	error = ext4_journal_get_create_access(handle, data_bh);
+	if (error) {
+		unlock_buffer(data_bh);
+		error = -EIO;
+		goto out_restore;
+	}
+	memset(data_bh->b_data, 0, inode->i_sb->s_blocksize);
+
+	if (!S_ISDIR(inode->i_mode)) {
+		memcpy(data_bh->b_data, buf, inline_size);
+		set_buffer_uptodate(data_bh);
+		unlock_buffer(data_bh);
+		error = ext4_handle_dirty_metadata(handle,
+						   inode, data_bh);
+	} else {
+		error = ext4_finish_convert_inline_dir(handle, inode, data_bh,
+						       buf, inline_size);
+	}
+
+out_restore:
+	if (error)
+		ext4_restore_inline_data(handle, inode, iloc, buf, inline_size);
+
+out:
+	brelse(data_bh);
+	kfree(buf);
+	return error;
+}
+
+/*
+ * Try to add the new entry to the inline data.
+ * If succeeds, return 0. If not, extended the inline dir and copied data to
+ * the new created block.
+ */
+int ext4_try_add_inline_entry(handle_t *handle, struct ext4_filename *fname,
+			      struct inode *dir, struct inode *inode)
+{
+	int ret, ret2, inline_size, no_expand;
+	void *inline_start;
+	struct ext4_iloc iloc;
+
+	ret = ext4_get_inode_loc(dir, &iloc);
+	if (ret)
+		return ret;
+
+	ext4_write_lock_xattr(dir, &no_expand);
+	if (!ext4_has_inline_data(dir))
+		goto out;
+
+	inline_start = (void *)ext4_raw_inode(&iloc)->i_block +
+						 EXT4_INLINE_DOTDOT_SIZE;
+	inline_size = EXT4_MIN_INLINE_DATA_SIZE - EXT4_INLINE_DOTDOT_SIZE;
+
+	ret = ext4_add_dirent_to_inline(handle, fname, dir, inode, &iloc,
+					inline_start, inline_size);
+	if (ret != -ENOSPC)
+		goto out;
+
+	/* check whether it can be inserted to inline xattr space. */
+	inline_size = EXT4_I(dir)->i_inline_size -
+			EXT4_MIN_INLINE_DATA_SIZE;
+	if (!inline_size) {
+		/* Try to use the xattr space.*/
+		ret = ext4_update_inline_dir(handle, dir, &iloc);
+		if (ret && ret != -ENOSPC)
+			goto out;
+
+		inline_size = EXT4_I(dir)->i_inline_size -
+				EXT4_MIN_INLINE_DATA_SIZE;
+	}
+
+	if (inline_size) {
+		inline_start = ext4_get_inline_xattr_pos(dir, &iloc);
+
+		ret = ext4_add_dirent_to_inline(handle, fname, dir,
+						inode, &iloc, inline_start,
+						inline_size);
+
+		if (ret != -ENOSPC)
+			goto out;
+	}
+
+	/*
+	 * The inline space is filled up, so create a new block for it.
+	 * As the extent tree will be created, we have to save the inline
+	 * dir first.
+	 */
+	ret = ext4_convert_inline_data_nolock(handle, dir, &iloc);
+
+out:
+	ext4_write_unlock_xattr(dir, &no_expand);
+	ret2 = ext4_mark_inode_dirty(handle, dir);
+	if (unlikely(ret2 && !ret))
+		ret = ret2;
+	brelse(iloc.bh);
+	return ret;
+}
+
+/*
+ * This function fills a red-black tree with information from an
+ * inlined dir.  It returns the number directory entries loaded
+ * into the tree.  If there is an error it is returned in err.
+ */
+int ext4_inlinedir_to_tree(struct file *dir_file,
+			   struct inode *dir, ext4_lblk_t block,
+			   struct dx_hash_info *hinfo,
+			   __u32 start_hash, __u32 start_minor_hash,
+			   int *has_inline_data)
+{
+	int err = 0, count = 0;
+	unsigned int parent_ino;
+	int pos;
+	struct ext4_dir_entry_2 *de;
+	struct inode *inode = file_inode(dir_file);
+	int ret, inline_size = 0;
+	struct ext4_iloc iloc;
+	void *dir_buf = NULL;
+	struct ext4_dir_entry_2 fake;
+	struct fscrypt_str tmp_str;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	if (!ext4_has_inline_data(inode)) {
+		up_read(&EXT4_I(inode)->xattr_sem);
+		*has_inline_data = 0;
+		goto out;
+	}
+
+	inline_size = ext4_get_inline_size(inode);
+	dir_buf = kmalloc(inline_size, GFP_NOFS);
+	if (!dir_buf) {
+		ret = -ENOMEM;
+		up_read(&EXT4_I(inode)->xattr_sem);
+		goto out;
+	}
+
+	ret = ext4_read_inline_data(inode, dir_buf, inline_size, &iloc);
+	up_read(&EXT4_I(inode)->xattr_sem);
+	if (ret < 0)
+		goto out;
+
+	pos = 0;
+	parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);
+	while (pos < inline_size) {
+		/*
+		 * As inlined dir doesn't store any information about '.' and
+		 * only the inode number of '..' is stored, we have to handle
+		 * them differently.
+		 */
+		if (pos == 0) {
+			fake.inode = cpu_to_le32(inode->i_ino);
+			fake.name_len = 1;
+			strcpy(fake.name, ".");
+			fake.rec_len = ext4_rec_len_to_disk(
+						EXT4_DIR_REC_LEN(fake.name_len),
+						inline_size);
+			ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
+			de = &fake;
+			pos = EXT4_INLINE_DOTDOT_OFFSET;
+		} else if (pos == EXT4_INLINE_DOTDOT_OFFSET) {
+			fake.inode = cpu_to_le32(parent_ino);
+			fake.name_len = 2;
+			strcpy(fake.name, "..");
+			fake.rec_len = ext4_rec_len_to_disk(
+						EXT4_DIR_REC_LEN(fake.name_len),
+						inline_size);
+			ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
+			de = &fake;
+			pos = EXT4_INLINE_DOTDOT_SIZE;
+		} else {
+			de = (struct ext4_dir_entry_2 *)(dir_buf + pos);
+			pos += ext4_rec_len_from_disk(de->rec_len, inline_size);
+			if (ext4_check_dir_entry(inode, dir_file, de,
+					 iloc.bh, dir_buf,
+					 inline_size, pos)) {
+				ret = count;
+				goto out;
+			}
+		}
+
+		ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
+		if ((hinfo->hash < start_hash) ||
+		    ((hinfo->hash == start_hash) &&
+		     (hinfo->minor_hash < start_minor_hash)))
+			continue;
+		if (de->inode == 0)
+			continue;
+		tmp_str.name = de->name;
+		tmp_str.len = de->name_len;
+		err = ext4_htree_store_dirent(dir_file, hinfo->hash,
+					      hinfo->minor_hash, de, &tmp_str);
+		if (err) {
+			ret = err;
+			goto out;
+		}
+		count++;
+	}
+	ret = count;
+out:
+	kfree(dir_buf);
+	brelse(iloc.bh);
+	return ret;
+}
+
+/*
+ * So this function is called when the volume is mkfsed with
+ * dir_index disabled. In order to keep f_pos persistent
+ * after we convert from an inlined dir to a blocked based,
+ * we just pretend that we are a normal dir and return the
+ * offset as if '.' and '..' really take place.
+ *
+ */
+int ext4_read_inline_dir(struct file *file,
+			 struct dir_context *ctx,
+			 int *has_inline_data)
+{
+	unsigned int offset, parent_ino;
+	int i;
+	struct ext4_dir_entry_2 *de;
+	struct super_block *sb;
+	struct inode *inode = file_inode(file);
+	int ret, inline_size = 0;
+	struct ext4_iloc iloc;
+	void *dir_buf = NULL;
+	int dotdot_offset, dotdot_size, extra_offset, extra_size;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	if (!ext4_has_inline_data(inode)) {
+		up_read(&EXT4_I(inode)->xattr_sem);
+		*has_inline_data = 0;
+		goto out;
+	}
+
+	inline_size = ext4_get_inline_size(inode);
+	dir_buf = kmalloc(inline_size, GFP_NOFS);
+	if (!dir_buf) {
+		ret = -ENOMEM;
+		up_read(&EXT4_I(inode)->xattr_sem);
+		goto out;
+	}
+
+	ret = ext4_read_inline_data(inode, dir_buf, inline_size, &iloc);
+	up_read(&EXT4_I(inode)->xattr_sem);
+	if (ret < 0)
+		goto out;
+
+	ret = 0;
+	sb = inode->i_sb;
+	parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);
+	offset = ctx->pos;
+
+	/*
+	 * dotdot_offset and dotdot_size is the real offset and
+	 * size for ".." and "." if the dir is block based while
+	 * the real size for them are only EXT4_INLINE_DOTDOT_SIZE.
+	 * So we will use extra_offset and extra_size to indicate them
+	 * during the inline dir iteration.
+	 */
+	dotdot_offset = EXT4_DIR_REC_LEN(1);
+	dotdot_size = dotdot_offset + EXT4_DIR_REC_LEN(2);
+	extra_offset = dotdot_size - EXT4_INLINE_DOTDOT_SIZE;
+	extra_size = extra_offset + inline_size;
+
+	/*
+	 * If the version has changed since the last call to
+	 * readdir(2), then we might be pointing to an invalid
+	 * dirent right now.  Scan from the start of the inline
+	 * dir to make sure.
+	 */
+	if (!inode_eq_iversion(inode, file->f_version)) {
+		for (i = 0; i < extra_size && i < offset;) {
+			/*
+			 * "." is with offset 0 and
+			 * ".." is dotdot_offset.
+			 */
+			if (!i) {
+				i = dotdot_offset;
+				continue;
+			} else if (i == dotdot_offset) {
+				i = dotdot_size;
+				continue;
+			}
+			/* for other entry, the real offset in
+			 * the buf has to be tuned accordingly.
+			 */
+			de = (struct ext4_dir_entry_2 *)
+				(dir_buf + i - extra_offset);
+			/* It's too expensive to do a full
+			 * dirent test each time round this
+			 * loop, but we do have to test at
+			 * least that it is non-zero.  A
+			 * failure will be detected in the
+			 * dirent test below. */
+			if (ext4_rec_len_from_disk(de->rec_len, extra_size)
+				< EXT4_DIR_REC_LEN(1))
+				break;
+			i += ext4_rec_len_from_disk(de->rec_len,
+						    extra_size);
+		}
+		offset = i;
+		ctx->pos = offset;
+		file->f_version = inode_query_iversion(inode);
+	}
+
+	while (ctx->pos < extra_size) {
+		if (ctx->pos == 0) {
+			if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
+				goto out;
+			ctx->pos = dotdot_offset;
+			continue;
+		}
+
+		if (ctx->pos == dotdot_offset) {
+			if (!dir_emit(ctx, "..", 2, parent_ino, DT_DIR))
+				goto out;
+			ctx->pos = dotdot_size;
+			continue;
+		}
+
+		de = (struct ext4_dir_entry_2 *)
+			(dir_buf + ctx->pos - extra_offset);
+		if (ext4_check_dir_entry(inode, file, de, iloc.bh, dir_buf,
+					 extra_size, ctx->pos))
+			goto out;
+		if (le32_to_cpu(de->inode)) {
+			if (!dir_emit(ctx, de->name, de->name_len,
+				      le32_to_cpu(de->inode),
+				      get_dtype(sb, de->file_type)))
+				goto out;
+		}
+		ctx->pos += ext4_rec_len_from_disk(de->rec_len, extra_size);
+	}
+out:
+	kfree(dir_buf);
+	brelse(iloc.bh);
+	return ret;
+}
+
+struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
+					struct ext4_dir_entry_2 **parent_de,
+					int *retval)
+{
+	struct ext4_iloc iloc;
+
+	*retval = ext4_get_inode_loc(inode, &iloc);
+	if (*retval)
+		return NULL;
+
+	*parent_de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;
+
+	return iloc.bh;
+}
+
+/*
+ * Try to create the inline data for the new dir.
+ * If it succeeds, return 0, otherwise return the error.
+ * In case of ENOSPC, the caller should create the normal disk layout dir.
+ */
+int ext4_try_create_inline_dir(handle_t *handle, struct inode *parent,
+			       struct inode *inode)
+{
+	int ret, inline_size = EXT4_MIN_INLINE_DATA_SIZE;
+	struct ext4_iloc iloc;
+	struct ext4_dir_entry_2 *de;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+	ret = ext4_prepare_inline_data(handle, inode, inline_size);
+	if (ret)
+		goto out;
+
+	/*
+	 * For inline dir, we only save the inode information for the ".."
+	 * and create a fake dentry to cover the left space.
+	 */
+	de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;
+	de->inode = cpu_to_le32(parent->i_ino);
+	de = (struct ext4_dir_entry_2 *)((void *)de + EXT4_INLINE_DOTDOT_SIZE);
+	de->inode = 0;
+	de->rec_len = ext4_rec_len_to_disk(
+				inline_size - EXT4_INLINE_DOTDOT_SIZE,
+				inline_size);
+	set_nlink(inode, 2);
+	inode->i_size = EXT4_I(inode)->i_disksize = inline_size;
+out:
+	brelse(iloc.bh);
+	return ret;
+}
+
+struct buffer_head *ext4_find_inline_entry(struct inode *dir,
+					struct ext4_filename *fname,
+					struct ext4_dir_entry_2 **res_dir,
+					int *has_inline_data)
+{
+	int ret;
+	struct ext4_iloc iloc;
+	void *inline_start;
+	int inline_size;
+
+	if (ext4_get_inode_loc(dir, &iloc))
+		return NULL;
+
+	down_read(&EXT4_I(dir)->xattr_sem);
+	if (!ext4_has_inline_data(dir)) {
+		*has_inline_data = 0;
+		goto out;
+	}
+
+	inline_start = (void *)ext4_raw_inode(&iloc)->i_block +
+						EXT4_INLINE_DOTDOT_SIZE;
+	inline_size = EXT4_MIN_INLINE_DATA_SIZE - EXT4_INLINE_DOTDOT_SIZE;
+	ret = ext4_search_dir(iloc.bh, inline_start, inline_size,
+			      dir, fname, 0, res_dir);
+	if (ret == 1)
+		goto out_find;
+	if (ret < 0)
+		goto out;
+
+	if (ext4_get_inline_size(dir) == EXT4_MIN_INLINE_DATA_SIZE)
+		goto out;
+
+	inline_start = ext4_get_inline_xattr_pos(dir, &iloc);
+	inline_size = ext4_get_inline_size(dir) - EXT4_MIN_INLINE_DATA_SIZE;
+
+	ret = ext4_search_dir(iloc.bh, inline_start, inline_size,
+			      dir, fname, 0, res_dir);
+	if (ret == 1)
+		goto out_find;
+
+out:
+	brelse(iloc.bh);
+	iloc.bh = NULL;
+out_find:
+	up_read(&EXT4_I(dir)->xattr_sem);
+	return iloc.bh;
+}
+
+int ext4_delete_inline_entry(handle_t *handle,
+			     struct inode *dir,
+			     struct ext4_dir_entry_2 *de_del,
+			     struct buffer_head *bh,
+			     int *has_inline_data)
+{
+	int err, inline_size, no_expand;
+	struct ext4_iloc iloc;
+	void *inline_start;
+
+	err = ext4_get_inode_loc(dir, &iloc);
+	if (err)
+		return err;
+
+	ext4_write_lock_xattr(dir, &no_expand);
+	if (!ext4_has_inline_data(dir)) {
+		*has_inline_data = 0;
+		goto out;
+	}
+
+	if ((void *)de_del - ((void *)ext4_raw_inode(&iloc)->i_block) <
+		EXT4_MIN_INLINE_DATA_SIZE) {
+		inline_start = (void *)ext4_raw_inode(&iloc)->i_block +
+					EXT4_INLINE_DOTDOT_SIZE;
+		inline_size = EXT4_MIN_INLINE_DATA_SIZE -
+				EXT4_INLINE_DOTDOT_SIZE;
+	} else {
+		inline_start = ext4_get_inline_xattr_pos(dir, &iloc);
+		inline_size = ext4_get_inline_size(dir) -
+				EXT4_MIN_INLINE_DATA_SIZE;
+	}
+
+	BUFFER_TRACE(bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, bh);
+	if (err)
+		goto out;
+
+	err = ext4_generic_delete_entry(dir, de_del, bh,
+					inline_start, inline_size, 0);
+	if (err)
+		goto out;
+
+	ext4_show_inline_dir(dir, iloc.bh, inline_start, inline_size);
+out:
+	ext4_write_unlock_xattr(dir, &no_expand);
+	if (likely(err == 0))
+		err = ext4_mark_inode_dirty(handle, dir);
+	brelse(iloc.bh);
+	if (err != -ENOENT)
+		ext4_std_error(dir->i_sb, err);
+	return err;
+}
+
+/*
+ * Get the inline dentry at offset.
+ */
+static inline struct ext4_dir_entry_2 *
+ext4_get_inline_entry(struct inode *inode,
+		      struct ext4_iloc *iloc,
+		      unsigned int offset,
+		      void **inline_start,
+		      int *inline_size)
+{
+	void *inline_pos;
+
+	BUG_ON(offset > ext4_get_inline_size(inode));
+
+	if (offset < EXT4_MIN_INLINE_DATA_SIZE) {
+		inline_pos = (void *)ext4_raw_inode(iloc)->i_block;
+		*inline_size = EXT4_MIN_INLINE_DATA_SIZE;
+	} else {
+		inline_pos = ext4_get_inline_xattr_pos(inode, iloc);
+		offset -= EXT4_MIN_INLINE_DATA_SIZE;
+		*inline_size = ext4_get_inline_size(inode) -
+				EXT4_MIN_INLINE_DATA_SIZE;
+	}
+
+	if (inline_start)
+		*inline_start = inline_pos;
+	return (struct ext4_dir_entry_2 *)(inline_pos + offset);
+}
+
+bool empty_inline_dir(struct inode *dir, int *has_inline_data)
+{
+	int err, inline_size;
+	struct ext4_iloc iloc;
+	size_t inline_len;
+	void *inline_pos;
+	unsigned int offset;
+	struct ext4_dir_entry_2 *de;
+	bool ret = false;
+
+	err = ext4_get_inode_loc(dir, &iloc);
+	if (err) {
+		EXT4_ERROR_INODE_ERR(dir, -err,
+				     "error %d getting inode %lu block",
+				     err, dir->i_ino);
+		return false;
+	}
+
+	down_read(&EXT4_I(dir)->xattr_sem);
+	if (!ext4_has_inline_data(dir)) {
+		*has_inline_data = 0;
+		ret = true;
+		goto out;
+	}
+
+	de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;
+	if (!le32_to_cpu(de->inode)) {
+		ext4_warning(dir->i_sb,
+			     "bad inline directory (dir #%lu) - no `..'",
+			     dir->i_ino);
+		goto out;
+	}
+
+	inline_len = ext4_get_inline_size(dir);
+	offset = EXT4_INLINE_DOTDOT_SIZE;
+	while (offset < inline_len) {
+		de = ext4_get_inline_entry(dir, &iloc, offset,
+					   &inline_pos, &inline_size);
+		if (ext4_check_dir_entry(dir, NULL, de,
+					 iloc.bh, inline_pos,
+					 inline_size, offset)) {
+			ext4_warning(dir->i_sb,
+				     "bad inline directory (dir #%lu) - "
+				     "inode %u, rec_len %u, name_len %d"
+				     "inline size %d",
+				     dir->i_ino, le32_to_cpu(de->inode),
+				     le16_to_cpu(de->rec_len), de->name_len,
+				     inline_size);
+			goto out;
+		}
+		if (le32_to_cpu(de->inode)) {
+			goto out;
+		}
+		offset += ext4_rec_len_from_disk(de->rec_len, inline_size);
+	}
+
+	ret = true;
+out:
+	up_read(&EXT4_I(dir)->xattr_sem);
+	brelse(iloc.bh);
+	return ret;
+}
+
+int ext4_destroy_inline_data(handle_t *handle, struct inode *inode)
+{
+	int ret, no_expand;
+
+	ext4_write_lock_xattr(inode, &no_expand);
+	ret = ext4_destroy_inline_data_nolock(handle, inode);
+	ext4_write_unlock_xattr(inode, &no_expand);
+
+	return ret;
+}
+
+int ext4_inline_data_iomap(struct inode *inode, struct iomap *iomap)
+{
+	__u64 addr;
+	int error = -EAGAIN;
+	struct ext4_iloc iloc;
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	if (!ext4_has_inline_data(inode))
+		goto out;
+
+	error = ext4_get_inode_loc(inode, &iloc);
+	if (error)
+		goto out;
+
+	addr = (__u64)iloc.bh->b_blocknr << inode->i_sb->s_blocksize_bits;
+	addr += (char *)ext4_raw_inode(&iloc) - iloc.bh->b_data;
+	addr += offsetof(struct ext4_inode, i_block);
+
+	brelse(iloc.bh);
+
+	iomap->addr = addr;
+	iomap->offset = 0;
+	iomap->length = min_t(loff_t, ext4_get_inline_size(inode),
+			      i_size_read(inode));
+	iomap->type = IOMAP_INLINE;
+	iomap->flags = 0;
+
+out:
+	up_read(&EXT4_I(inode)->xattr_sem);
+	return error;
+}
+
+int ext4_inline_data_truncate(struct inode *inode, int *has_inline)
+{
+	handle_t *handle;
+	int inline_size, value_len, needed_blocks, no_expand, err = 0;
+	size_t i_size;
+	void *value = NULL;
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext4_xattr_info i = {
+		.name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_DATA,
+	};
+
+
+	needed_blocks = ext4_writepage_trans_blocks(inode);
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, needed_blocks);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	ext4_write_lock_xattr(inode, &no_expand);
+	if (!ext4_has_inline_data(inode)) {
+		ext4_write_unlock_xattr(inode, &no_expand);
+		*has_inline = 0;
+		ext4_journal_stop(handle);
+		return 0;
+	}
+
+	if ((err = ext4_orphan_add(handle, inode)) != 0)
+		goto out;
+
+	if ((err = ext4_get_inode_loc(inode, &is.iloc)) != 0)
+		goto out;
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	i_size = inode->i_size;
+	inline_size = ext4_get_inline_size(inode);
+	EXT4_I(inode)->i_disksize = i_size;
+
+	if (i_size < inline_size) {
+		/* Clear the content in the xattr space. */
+		if (inline_size > EXT4_MIN_INLINE_DATA_SIZE) {
+			if ((err = ext4_xattr_ibody_find(inode, &i, &is)) != 0)
+				goto out_error;
+
+			BUG_ON(is.s.not_found);
+
+			value_len = le32_to_cpu(is.s.here->e_value_size);
+			value = kmalloc(value_len, GFP_NOFS);
+			if (!value) {
+				err = -ENOMEM;
+				goto out_error;
+			}
+
+			err = ext4_xattr_ibody_get(inode, i.name_index,
+						   i.name, value, value_len);
+			if (err <= 0)
+				goto out_error;
+
+			i.value = value;
+			i.value_len = i_size > EXT4_MIN_INLINE_DATA_SIZE ?
+					i_size - EXT4_MIN_INLINE_DATA_SIZE : 0;
+			err = ext4_xattr_ibody_set(handle, inode, &i, &is);
+			if (err)
+				goto out_error;
+		}
+
+		/* Clear the content within i_blocks. */
+		if (i_size < EXT4_MIN_INLINE_DATA_SIZE) {
+			void *p = (void *) ext4_raw_inode(&is.iloc)->i_block;
+			memset(p + i_size, 0,
+			       EXT4_MIN_INLINE_DATA_SIZE - i_size);
+		}
+
+		EXT4_I(inode)->i_inline_size = i_size <
+					EXT4_MIN_INLINE_DATA_SIZE ?
+					EXT4_MIN_INLINE_DATA_SIZE : i_size;
+	}
+
+out_error:
+	up_write(&EXT4_I(inode)->i_data_sem);
+out:
+	brelse(is.iloc.bh);
+	ext4_write_unlock_xattr(inode, &no_expand);
+	kfree(value);
+	if (inode->i_nlink)
+		ext4_orphan_del(handle, inode);
+
+	if (err == 0) {
+		inode->i_mtime = inode->i_ctime = current_time(inode);
+		err = ext4_mark_inode_dirty(handle, inode);
+		if (IS_SYNC(inode))
+			ext4_handle_sync(handle);
+	}
+	ext4_journal_stop(handle);
+	return err;
+}
+
+int ext4_convert_inline_data(struct inode *inode)
+{
+	int error, needed_blocks, no_expand;
+	handle_t *handle;
+	struct ext4_iloc iloc;
+
+	if (!ext4_has_inline_data(inode)) {
+		ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+		return 0;
+	} else if (!ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
+		/*
+		 * Inode has inline data but EXT4_STATE_MAY_INLINE_DATA is
+		 * cleared. This means we are in the middle of moving of
+		 * inline data to delay allocated block. Just force writeout
+		 * here to finish conversion.
+		 */
+		error = filemap_flush(inode->i_mapping);
+		if (error)
+			return error;
+		if (!ext4_has_inline_data(inode))
+			return 0;
+	}
+
+	needed_blocks = ext4_writepage_trans_blocks(inode);
+
+	iloc.bh = NULL;
+	error = ext4_get_inode_loc(inode, &iloc);
+	if (error)
+		return error;
+
+	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
+	if (IS_ERR(handle)) {
+		error = PTR_ERR(handle);
+		goto out_free;
+	}
+
+	ext4_write_lock_xattr(inode, &no_expand);
+	if (ext4_has_inline_data(inode))
+		error = ext4_convert_inline_data_nolock(handle, inode, &iloc);
+	ext4_write_unlock_xattr(inode, &no_expand);
+	ext4_journal_stop(handle);
+out_free:
+	brelse(iloc.bh);
+	return error;
+}
diff --git a/fs/ext4/inode-test.c b/fs/ext4/inode-test.c
new file mode 100644
index 000000000..d62d802c9
--- /dev/null
+++ b/fs/ext4/inode-test.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test of ext4 inode that verify the seconds part of [a/c/m]
+ * timestamps in ext4 inode structs are decoded correctly.
+ */
+
+#include <kunit/test.h>
+#include <linux/kernel.h>
+#include <linux/time64.h>
+
+#include "ext4.h"
+
+/*
+ * For constructing the nonnegative timestamp lower bound value.
+ * binary: 00000000 00000000 00000000 00000000
+ */
+#define LOWER_MSB_0 0L
+/*
+ * For constructing the nonnegative timestamp upper bound value.
+ * binary: 01111111 11111111 11111111 11111111
+ *
+ */
+#define UPPER_MSB_0 0x7fffffffL
+/*
+ * For constructing the negative timestamp lower bound value.
+ * binary: 10000000 00000000 00000000 00000000
+ */
+#define LOWER_MSB_1 (-(UPPER_MSB_0) - 1L)  /* avoid overflow */
+/*
+ * For constructing the negative timestamp upper bound value.
+ * binary: 11111111 11111111 11111111 11111111
+ */
+#define UPPER_MSB_1 (-1L)
+/*
+ * Upper bound for nanoseconds value supported by the encoding.
+ * binary: 00111111 11111111 11111111 11111111
+ */
+#define MAX_NANOSECONDS ((1L << 30) - 1)
+
+#define CASE_NAME_FORMAT "%s: msb:%x lower_bound:%x extra_bits: %x"
+
+#define LOWER_BOUND_NEG_NO_EXTRA_BITS_CASE\
+	"1901-12-13 Lower bound of 32bit < 0 timestamp, no extra bits"
+#define UPPER_BOUND_NEG_NO_EXTRA_BITS_CASE\
+	"1969-12-31 Upper bound of 32bit < 0 timestamp, no extra bits"
+#define LOWER_BOUND_NONNEG_NO_EXTRA_BITS_CASE\
+	"1970-01-01 Lower bound of 32bit >=0 timestamp, no extra bits"
+#define UPPER_BOUND_NONNEG_NO_EXTRA_BITS_CASE\
+	"2038-01-19 Upper bound of 32bit >=0 timestamp, no extra bits"
+#define LOWER_BOUND_NEG_LO_1_CASE\
+	"2038-01-19 Lower bound of 32bit <0 timestamp, lo extra sec bit on"
+#define UPPER_BOUND_NEG_LO_1_CASE\
+	"2106-02-07 Upper bound of 32bit <0 timestamp, lo extra sec bit on"
+#define LOWER_BOUND_NONNEG_LO_1_CASE\
+	"2106-02-07 Lower bound of 32bit >=0 timestamp, lo extra sec bit on"
+#define UPPER_BOUND_NONNEG_LO_1_CASE\
+	"2174-02-25 Upper bound of 32bit >=0 timestamp, lo extra sec bit on"
+#define LOWER_BOUND_NEG_HI_1_CASE\
+	"2174-02-25 Lower bound of 32bit <0 timestamp, hi extra sec bit on"
+#define UPPER_BOUND_NEG_HI_1_CASE\
+	"2242-03-16 Upper bound of 32bit <0 timestamp, hi extra sec bit on"
+#define LOWER_BOUND_NONNEG_HI_1_CASE\
+	"2242-03-16 Lower bound of 32bit >=0 timestamp, hi extra sec bit on"
+#define UPPER_BOUND_NONNEG_HI_1_CASE\
+	"2310-04-04 Upper bound of 32bit >=0 timestamp, hi extra sec bit on"
+#define UPPER_BOUND_NONNEG_HI_1_NS_1_CASE\
+	"2310-04-04 Upper bound of 32bit>=0 timestamp, hi extra sec bit 1. 1 ns"
+#define LOWER_BOUND_NONNEG_HI_1_NS_MAX_CASE\
+	"2378-04-22 Lower bound of 32bit>= timestamp. Extra sec bits 1. Max ns"
+#define LOWER_BOUND_NONNEG_EXTRA_BITS_1_CASE\
+	"2378-04-22 Lower bound of 32bit >=0 timestamp. All extra sec bits on"
+#define UPPER_BOUND_NONNEG_EXTRA_BITS_1_CASE\
+	"2446-05-10 Upper bound of 32bit >=0 timestamp. All extra sec bits on"
+
+struct timestamp_expectation {
+	const char *test_case_name;
+	struct timespec64 expected;
+	u32 extra_bits;
+	bool msb_set;
+	bool lower_bound;
+};
+
+static time64_t get_32bit_time(const struct timestamp_expectation * const test)
+{
+	if (test->msb_set) {
+		if (test->lower_bound)
+			return LOWER_MSB_1;
+
+		return UPPER_MSB_1;
+	}
+
+	if (test->lower_bound)
+		return LOWER_MSB_0;
+	return UPPER_MSB_0;
+}
+
+
+/*
+ *  Test data is derived from the table in the Inode Timestamps section of
+ *  Documentation/filesystems/ext4/inodes.rst.
+ */
+static void inode_test_xtimestamp_decoding(struct kunit *test)
+{
+	const struct timestamp_expectation test_data[] = {
+		{
+			.test_case_name = LOWER_BOUND_NEG_NO_EXTRA_BITS_CASE,
+			.msb_set = true,
+			.lower_bound = true,
+			.extra_bits = 0,
+			.expected = {.tv_sec = -0x80000000LL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NEG_NO_EXTRA_BITS_CASE,
+			.msb_set = true,
+			.lower_bound = false,
+			.extra_bits = 0,
+			.expected = {.tv_sec = -1LL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = LOWER_BOUND_NONNEG_NO_EXTRA_BITS_CASE,
+			.msb_set = false,
+			.lower_bound = true,
+			.extra_bits = 0,
+			.expected = {0LL, 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NONNEG_NO_EXTRA_BITS_CASE,
+			.msb_set = false,
+			.lower_bound = false,
+			.extra_bits = 0,
+			.expected = {.tv_sec = 0x7fffffffLL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = LOWER_BOUND_NEG_LO_1_CASE,
+			.msb_set = true,
+			.lower_bound = true,
+			.extra_bits = 1,
+			.expected = {.tv_sec = 0x80000000LL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NEG_LO_1_CASE,
+			.msb_set = true,
+			.lower_bound = false,
+			.extra_bits = 1,
+			.expected = {.tv_sec = 0xffffffffLL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = LOWER_BOUND_NONNEG_LO_1_CASE,
+			.msb_set = false,
+			.lower_bound = true,
+			.extra_bits = 1,
+			.expected = {.tv_sec = 0x100000000LL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NONNEG_LO_1_CASE,
+			.msb_set = false,
+			.lower_bound = false,
+			.extra_bits = 1,
+			.expected = {.tv_sec = 0x17fffffffLL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = LOWER_BOUND_NEG_HI_1_CASE,
+			.msb_set = true,
+			.lower_bound = true,
+			.extra_bits =  2,
+			.expected = {.tv_sec = 0x180000000LL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NEG_HI_1_CASE,
+			.msb_set = true,
+			.lower_bound = false,
+			.extra_bits = 2,
+			.expected = {.tv_sec = 0x1ffffffffLL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = LOWER_BOUND_NONNEG_HI_1_CASE,
+			.msb_set = false,
+			.lower_bound = true,
+			.extra_bits = 2,
+			.expected = {.tv_sec = 0x200000000LL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NONNEG_HI_1_CASE,
+			.msb_set = false,
+			.lower_bound = false,
+			.extra_bits = 2,
+			.expected = {.tv_sec = 0x27fffffffLL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NONNEG_HI_1_NS_1_CASE,
+			.msb_set = false,
+			.lower_bound = false,
+			.extra_bits = 6,
+			.expected = {.tv_sec = 0x27fffffffLL, .tv_nsec = 1L},
+		},
+
+		{
+			.test_case_name = LOWER_BOUND_NONNEG_HI_1_NS_MAX_CASE,
+			.msb_set = false,
+			.lower_bound = true,
+			.extra_bits = 0xFFFFFFFF,
+			.expected = {.tv_sec = 0x300000000LL,
+				     .tv_nsec = MAX_NANOSECONDS},
+		},
+
+		{
+			.test_case_name = LOWER_BOUND_NONNEG_EXTRA_BITS_1_CASE,
+			.msb_set = false,
+			.lower_bound = true,
+			.extra_bits = 3,
+			.expected = {.tv_sec = 0x300000000LL, .tv_nsec = 0L},
+		},
+
+		{
+			.test_case_name = UPPER_BOUND_NONNEG_EXTRA_BITS_1_CASE,
+			.msb_set = false,
+			.lower_bound = false,
+			.extra_bits = 3,
+			.expected = {.tv_sec = 0x37fffffffLL, .tv_nsec = 0L},
+		}
+	};
+
+	struct timespec64 timestamp;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(test_data); ++i) {
+		timestamp.tv_sec = get_32bit_time(&test_data[i]);
+		ext4_decode_extra_time(&timestamp,
+				       cpu_to_le32(test_data[i].extra_bits));
+
+		KUNIT_EXPECT_EQ_MSG(test,
+				    test_data[i].expected.tv_sec,
+				    timestamp.tv_sec,
+				    CASE_NAME_FORMAT,
+				    test_data[i].test_case_name,
+				    test_data[i].msb_set,
+				    test_data[i].lower_bound,
+				    test_data[i].extra_bits);
+		KUNIT_EXPECT_EQ_MSG(test,
+				    test_data[i].expected.tv_nsec,
+				    timestamp.tv_nsec,
+				    CASE_NAME_FORMAT,
+				    test_data[i].test_case_name,
+				    test_data[i].msb_set,
+				    test_data[i].lower_bound,
+				    test_data[i].extra_bits);
+	}
+}
+
+static struct kunit_case ext4_inode_test_cases[] = {
+	KUNIT_CASE(inode_test_xtimestamp_decoding),
+	{}
+};
+
+static struct kunit_suite ext4_inode_test_suite = {
+	.name = "ext4_inode_test",
+	.test_cases = ext4_inode_test_cases,
+};
+
+kunit_test_suites(&ext4_inode_test_suite);
+
+MODULE_LICENSE("GPL v2");
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
new file mode 100644
index 000000000..365c4d3a4
--- /dev/null
+++ b/fs/ext4/inode.c
@@ -0,0 +1,6319 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ *	(jj@sunsite.ms.mff.cuni.cz)
+ *
+ *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
+ */
+
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/dax.h>
+#include <linux/quotaops.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include <linux/mpage.h>
+#include <linux/namei.h>
+#include <linux/uio.h>
+#include <linux/bio.h>
+#include <linux/workqueue.h>
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/iomap.h>
+#include <linux/iversion.h>
+
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "truncate.h"
+
+#include <trace/events/ext4.h>
+
+static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
+			      struct ext4_inode_info *ei)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	__u32 csum;
+	__u16 dummy_csum = 0;
+	int offset = offsetof(struct ext4_inode, i_checksum_lo);
+	unsigned int csum_size = sizeof(dummy_csum);
+
+	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
+	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
+	offset += csum_size;
+	csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
+			   EXT4_GOOD_OLD_INODE_SIZE - offset);
+
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+		offset = offsetof(struct ext4_inode, i_checksum_hi);
+		csum = ext4_chksum(sbi, csum, (__u8 *)raw +
+				   EXT4_GOOD_OLD_INODE_SIZE,
+				   offset - EXT4_GOOD_OLD_INODE_SIZE);
+		if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
+			csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
+					   csum_size);
+			offset += csum_size;
+		}
+		csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
+				   EXT4_INODE_SIZE(inode->i_sb) - offset);
+	}
+
+	return csum;
+}
+
+static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
+				  struct ext4_inode_info *ei)
+{
+	__u32 provided, calculated;
+
+	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
+	    cpu_to_le32(EXT4_OS_LINUX) ||
+	    !ext4_has_metadata_csum(inode->i_sb))
+		return 1;
+
+	provided = le16_to_cpu(raw->i_checksum_lo);
+	calculated = ext4_inode_csum(inode, raw, ei);
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
+	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
+		provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
+	else
+		calculated &= 0xFFFF;
+
+	return provided == calculated;
+}
+
+void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
+			 struct ext4_inode_info *ei)
+{
+	__u32 csum;
+
+	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
+	    cpu_to_le32(EXT4_OS_LINUX) ||
+	    !ext4_has_metadata_csum(inode->i_sb))
+		return;
+
+	csum = ext4_inode_csum(inode, raw, ei);
+	raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
+	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
+		raw->i_checksum_hi = cpu_to_le16(csum >> 16);
+}
+
+static inline int ext4_begin_ordered_truncate(struct inode *inode,
+					      loff_t new_size)
+{
+	trace_ext4_begin_ordered_truncate(inode, new_size);
+	/*
+	 * If jinode is zero, then we never opened the file for
+	 * writing, so there's no need to call
+	 * jbd2_journal_begin_ordered_truncate() since there's no
+	 * outstanding writes we need to flush.
+	 */
+	if (!EXT4_I(inode)->jinode)
+		return 0;
+	return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
+						   EXT4_I(inode)->jinode,
+						   new_size);
+}
+
+static void ext4_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length);
+static int __ext4_journalled_writepage(struct page *page, unsigned int len);
+static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+				  int pextents);
+
+/*
+ * Test whether an inode is a fast symlink.
+ * A fast symlink has its symlink data stored in ext4_inode_info->i_data.
+ */
+int ext4_inode_is_fast_symlink(struct inode *inode)
+{
+	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
+		int ea_blocks = EXT4_I(inode)->i_file_acl ?
+				EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
+
+		if (ext4_has_inline_data(inode))
+			return 0;
+
+		return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
+	}
+	return S_ISLNK(inode->i_mode) && inode->i_size &&
+	       (inode->i_size < EXT4_N_BLOCKS * 4);
+}
+
+/*
+ * Called at the last iput() if i_nlink is zero.
+ */
+void ext4_evict_inode(struct inode *inode)
+{
+	handle_t *handle;
+	int err;
+	/*
+	 * Credits for final inode cleanup and freeing:
+	 * sb + inode (ext4_orphan_del()), block bitmap, group descriptor
+	 * (xattr block freeing), bitmap, group descriptor (inode freeing)
+	 */
+	int extra_credits = 6;
+	struct ext4_xattr_inode_array *ea_inode_array = NULL;
+	bool freeze_protected = false;
+
+	trace_ext4_evict_inode(inode);
+
+	if (EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)
+		ext4_evict_ea_inode(inode);
+	if (inode->i_nlink) {
+		/*
+		 * When journalling data dirty buffers are tracked only in the
+		 * journal. So although mm thinks everything is clean and
+		 * ready for reaping the inode might still have some pages to
+		 * write in the running transaction or waiting to be
+		 * checkpointed. Thus calling jbd2_journal_invalidatepage()
+		 * (via truncate_inode_pages()) to discard these buffers can
+		 * cause data loss. Also even if we did not discard these
+		 * buffers, we would have no way to find them after the inode
+		 * is reaped and thus user could see stale data if he tries to
+		 * read them before the transaction is checkpointed. So be
+		 * careful and force everything to disk here... We use
+		 * ei->i_datasync_tid to store the newest transaction
+		 * containing inode's data.
+		 *
+		 * Note that directories do not have this problem because they
+		 * don't use page cache.
+		 */
+		if (inode->i_ino != EXT4_JOURNAL_INO &&
+		    ext4_should_journal_data(inode) &&
+		    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
+		    inode->i_data.nrpages) {
+			journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+			tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
+
+			jbd2_complete_transaction(journal, commit_tid);
+			filemap_write_and_wait(&inode->i_data);
+		}
+		truncate_inode_pages_final(&inode->i_data);
+
+		goto no_delete;
+	}
+
+	if (is_bad_inode(inode))
+		goto no_delete;
+	dquot_initialize(inode);
+
+	if (ext4_should_order_data(inode))
+		ext4_begin_ordered_truncate(inode, 0);
+	truncate_inode_pages_final(&inode->i_data);
+
+	/*
+	 * For inodes with journalled data, transaction commit could have
+	 * dirtied the inode. And for inodes with dioread_nolock, unwritten
+	 * extents converting worker could merge extents and also have dirtied
+	 * the inode. Flush worker is ignoring it because of I_FREEING flag but
+	 * we still need to remove the inode from the writeback lists.
+	 */
+	if (!list_empty_careful(&inode->i_io_list))
+		inode_io_list_del(inode);
+
+	/*
+	 * Protect us against freezing - iput() caller didn't have to have any
+	 * protection against it. When we are in a running transaction though,
+	 * we are already protected against freezing and we cannot grab further
+	 * protection due to lock ordering constraints.
+	 */
+	if (!ext4_journal_current_handle()) {
+		sb_start_intwrite(inode->i_sb);
+		freeze_protected = true;
+	}
+
+	if (!IS_NOQUOTA(inode))
+		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
+
+	/*
+	 * Block bitmap, group descriptor, and inode are accounted in both
+	 * ext4_blocks_for_truncate() and extra_credits. So subtract 3.
+	 */
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
+			 ext4_blocks_for_truncate(inode) + extra_credits - 3);
+	if (IS_ERR(handle)) {
+		ext4_std_error(inode->i_sb, PTR_ERR(handle));
+		/*
+		 * If we're going to skip the normal cleanup, we still need to
+		 * make sure that the in-core orphan linked list is properly
+		 * cleaned up.
+		 */
+		ext4_orphan_del(NULL, inode);
+		if (freeze_protected)
+			sb_end_intwrite(inode->i_sb);
+		goto no_delete;
+	}
+
+	if (IS_SYNC(inode))
+		ext4_handle_sync(handle);
+
+	/*
+	 * Set inode->i_size to 0 before calling ext4_truncate(). We need
+	 * special handling of symlinks here because i_size is used to
+	 * determine whether ext4_inode_info->i_data contains symlink data or
+	 * block mappings. Setting i_size to 0 will remove its fast symlink
+	 * status. Erase i_data so that it becomes a valid empty block map.
+	 */
+	if (ext4_inode_is_fast_symlink(inode))
+		memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
+	inode->i_size = 0;
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (err) {
+		ext4_warning(inode->i_sb,
+			     "couldn't mark inode dirty (err %d)", err);
+		goto stop_handle;
+	}
+	if (inode->i_blocks) {
+		err = ext4_truncate(inode);
+		if (err) {
+			ext4_error_err(inode->i_sb, -err,
+				       "couldn't truncate inode %lu (err %d)",
+				       inode->i_ino, err);
+			goto stop_handle;
+		}
+	}
+
+	/* Remove xattr references. */
+	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
+				      extra_credits);
+	if (err) {
+		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
+stop_handle:
+		ext4_journal_stop(handle);
+		ext4_orphan_del(NULL, inode);
+		if (freeze_protected)
+			sb_end_intwrite(inode->i_sb);
+		ext4_xattr_inode_array_free(ea_inode_array);
+		goto no_delete;
+	}
+
+	/*
+	 * Kill off the orphan record which ext4_truncate created.
+	 * AKPM: I think this can be inside the above `if'.
+	 * Note that ext4_orphan_del() has to be able to cope with the
+	 * deletion of a non-existent orphan - this is because we don't
+	 * know if ext4_truncate() actually created an orphan record.
+	 * (Well, we could do this if we need to, but heck - it works)
+	 */
+	ext4_orphan_del(handle, inode);
+	EXT4_I(inode)->i_dtime	= (__u32)ktime_get_real_seconds();
+
+	/*
+	 * One subtle ordering requirement: if anything has gone wrong
+	 * (transaction abort, IO errors, whatever), then we can still
+	 * do these next steps (the fs will already have been marked as
+	 * having errors), but we can't free the inode if the mark_dirty
+	 * fails.
+	 */
+	if (ext4_mark_inode_dirty(handle, inode))
+		/* If that failed, just do the required in-core inode clear. */
+		ext4_clear_inode(inode);
+	else
+		ext4_free_inode(handle, inode);
+	ext4_journal_stop(handle);
+	if (freeze_protected)
+		sb_end_intwrite(inode->i_sb);
+	ext4_xattr_inode_array_free(ea_inode_array);
+	return;
+no_delete:
+	/*
+	 * Check out some where else accidentally dirty the evicting inode,
+	 * which may probably cause inode use-after-free issues later.
+	 */
+	WARN_ON_ONCE(!list_empty_careful(&inode->i_io_list));
+
+	if (!list_empty(&EXT4_I(inode)->i_fc_list))
+		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM);
+	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
+}
+
+#ifdef CONFIG_QUOTA
+qsize_t *ext4_get_reserved_space(struct inode *inode)
+{
+	return &EXT4_I(inode)->i_reserved_quota;
+}
+#endif
+
+/*
+ * Called with i_data_sem down, which is important since we can call
+ * ext4_discard_preallocations() from here.
+ */
+void ext4_da_update_reserve_space(struct inode *inode,
+					int used, int quota_claim)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	spin_lock(&ei->i_block_reservation_lock);
+	trace_ext4_da_update_reserve_space(inode, used, quota_claim);
+	if (unlikely(used > ei->i_reserved_data_blocks)) {
+		ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
+			 "with only %d reserved data blocks",
+			 __func__, inode->i_ino, used,
+			 ei->i_reserved_data_blocks);
+		WARN_ON(1);
+		used = ei->i_reserved_data_blocks;
+	}
+
+	/* Update per-inode reservations */
+	ei->i_reserved_data_blocks -= used;
+	percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
+
+	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
+	/* Update quota subsystem for data blocks */
+	if (quota_claim)
+		dquot_claim_block(inode, EXT4_C2B(sbi, used));
+	else {
+		/*
+		 * We did fallocate with an offset that is already delayed
+		 * allocated. So on delayed allocated writeback we should
+		 * not re-claim the quota for fallocated blocks.
+		 */
+		dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
+	}
+
+	/*
+	 * If we have done all the pending block allocations and if
+	 * there aren't any writers on the inode, we can discard the
+	 * inode's preallocations.
+	 */
+	if ((ei->i_reserved_data_blocks == 0) &&
+	    !inode_is_open_for_write(inode))
+		ext4_discard_preallocations(inode, 0);
+}
+
+static int __check_block_validity(struct inode *inode, const char *func,
+				unsigned int line,
+				struct ext4_map_blocks *map)
+{
+	if (ext4_has_feature_journal(inode->i_sb) &&
+	    (inode->i_ino ==
+	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
+		return 0;
+	if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
+		ext4_error_inode(inode, func, line, map->m_pblk,
+				 "lblock %lu mapped to illegal pblock %llu "
+				 "(length %d)", (unsigned long) map->m_lblk,
+				 map->m_pblk, map->m_len);
+		return -EFSCORRUPTED;
+	}
+	return 0;
+}
+
+int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
+		       ext4_lblk_t len)
+{
+	int ret;
+
+	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
+		return fscrypt_zeroout_range(inode, lblk, pblk, len);
+
+	ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
+	if (ret > 0)
+		ret = 0;
+
+	return ret;
+}
+
+#define check_block_validity(inode, map)	\
+	__check_block_validity((inode), __func__, __LINE__, (map))
+
+#ifdef ES_AGGRESSIVE_TEST
+static void ext4_map_blocks_es_recheck(handle_t *handle,
+				       struct inode *inode,
+				       struct ext4_map_blocks *es_map,
+				       struct ext4_map_blocks *map,
+				       int flags)
+{
+	int retval;
+
+	map->m_flags = 0;
+	/*
+	 * There is a race window that the result is not the same.
+	 * e.g. xfstests #223 when dioread_nolock enables.  The reason
+	 * is that we lookup a block mapping in extent status tree with
+	 * out taking i_data_sem.  So at the time the unwritten extent
+	 * could be converted.
+	 */
+	down_read(&EXT4_I(inode)->i_data_sem);
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		retval = ext4_ext_map_blocks(handle, inode, map, 0);
+	} else {
+		retval = ext4_ind_map_blocks(handle, inode, map, 0);
+	}
+	up_read((&EXT4_I(inode)->i_data_sem));
+
+	/*
+	 * We don't check m_len because extent will be collpased in status
+	 * tree.  So the m_len might not equal.
+	 */
+	if (es_map->m_lblk != map->m_lblk ||
+	    es_map->m_flags != map->m_flags ||
+	    es_map->m_pblk != map->m_pblk) {
+		printk("ES cache assertion failed for inode: %lu "
+		       "es_cached ex [%d/%d/%llu/%x] != "
+		       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
+		       inode->i_ino, es_map->m_lblk, es_map->m_len,
+		       es_map->m_pblk, es_map->m_flags, map->m_lblk,
+		       map->m_len, map->m_pblk, map->m_flags,
+		       retval, flags);
+	}
+}
+#endif /* ES_AGGRESSIVE_TEST */
+
+/*
+ * The ext4_map_blocks() function tries to look up the requested blocks,
+ * and returns if the blocks are already mapped.
+ *
+ * Otherwise it takes the write lock of the i_data_sem and allocate blocks
+ * and store the allocated blocks in the result buffer head and mark it
+ * mapped.
+ *
+ * If file type is extents based, it will call ext4_ext_map_blocks(),
+ * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
+ * based files
+ *
+ * On success, it returns the number of blocks being mapped or allocated.  if
+ * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
+ * is marked as unwritten. If the create == 1, it will mark @map as mapped.
+ *
+ * It returns 0 if plain look up failed (blocks have not been allocated), in
+ * that case, @map is returned as unmapped but we still do fill map->m_len to
+ * indicate the length of a hole starting at map->m_lblk.
+ *
+ * It returns the error in case of allocation failure.
+ */
+int ext4_map_blocks(handle_t *handle, struct inode *inode,
+		    struct ext4_map_blocks *map, int flags)
+{
+	struct extent_status es;
+	int retval;
+	int ret = 0;
+#ifdef ES_AGGRESSIVE_TEST
+	struct ext4_map_blocks orig_map;
+
+	memcpy(&orig_map, map, sizeof(*map));
+#endif
+
+	map->m_flags = 0;
+	ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
+		  flags, map->m_len, (unsigned long) map->m_lblk);
+
+	/*
+	 * ext4_map_blocks returns an int, and m_len is an unsigned int
+	 */
+	if (unlikely(map->m_len > INT_MAX))
+		map->m_len = INT_MAX;
+
+	/* We can handle the block number less than EXT_MAX_BLOCKS */
+	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
+		return -EFSCORRUPTED;
+
+	/* Lookup extent status tree firstly */
+	if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
+	    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
+		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
+			map->m_pblk = ext4_es_pblock(&es) +
+					map->m_lblk - es.es_lblk;
+			map->m_flags |= ext4_es_is_written(&es) ?
+					EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
+			retval = es.es_len - (map->m_lblk - es.es_lblk);
+			if (retval > map->m_len)
+				retval = map->m_len;
+			map->m_len = retval;
+		} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
+			map->m_pblk = 0;
+			retval = es.es_len - (map->m_lblk - es.es_lblk);
+			if (retval > map->m_len)
+				retval = map->m_len;
+			map->m_len = retval;
+			retval = 0;
+		} else {
+			BUG();
+		}
+#ifdef ES_AGGRESSIVE_TEST
+		ext4_map_blocks_es_recheck(handle, inode, map,
+					   &orig_map, flags);
+#endif
+		goto found;
+	}
+
+	/*
+	 * Try to see if we can get the block without requesting a new
+	 * file system block.
+	 */
+	down_read(&EXT4_I(inode)->i_data_sem);
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		retval = ext4_ext_map_blocks(handle, inode, map, 0);
+	} else {
+		retval = ext4_ind_map_blocks(handle, inode, map, 0);
+	}
+	if (retval > 0) {
+		unsigned int status;
+
+		if (unlikely(retval != map->m_len)) {
+			ext4_warning(inode->i_sb,
+				     "ES len assertion failed for inode "
+				     "%lu: retval %d != map->m_len %d",
+				     inode->i_ino, retval, map->m_len);
+			WARN_ON(1);
+		}
+
+		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
+		    !(status & EXTENT_STATUS_WRITTEN) &&
+		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
+				       map->m_lblk + map->m_len - 1))
+			status |= EXTENT_STATUS_DELAYED;
+		ret = ext4_es_insert_extent(inode, map->m_lblk,
+					    map->m_len, map->m_pblk, status);
+		if (ret < 0)
+			retval = ret;
+	}
+	up_read((&EXT4_I(inode)->i_data_sem));
+
+found:
+	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
+		ret = check_block_validity(inode, map);
+		if (ret != 0)
+			return ret;
+	}
+
+	/* If it is only a block(s) look up */
+	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
+		return retval;
+
+	/*
+	 * Returns if the blocks have already allocated
+	 *
+	 * Note that if blocks have been preallocated
+	 * ext4_ext_get_block() returns the create = 0
+	 * with buffer head unmapped.
+	 */
+	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
+		/*
+		 * If we need to convert extent to unwritten
+		 * we continue and do the actual work in
+		 * ext4_ext_map_blocks()
+		 */
+		if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
+			return retval;
+
+	/*
+	 * Here we clear m_flags because after allocating an new extent,
+	 * it will be set again.
+	 */
+	map->m_flags &= ~EXT4_MAP_FLAGS;
+
+	/*
+	 * New blocks allocate and/or writing to unwritten extent
+	 * will possibly result in updating i_data, so we take
+	 * the write lock of i_data_sem, and call get_block()
+	 * with create == 1 flag.
+	 */
+	down_write(&EXT4_I(inode)->i_data_sem);
+
+	/*
+	 * We need to check for EXT4 here because migrate
+	 * could have changed the inode type in between
+	 */
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		retval = ext4_ext_map_blocks(handle, inode, map, flags);
+	} else {
+		retval = ext4_ind_map_blocks(handle, inode, map, flags);
+
+		if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
+			/*
+			 * We allocated new blocks which will result in
+			 * i_data's format changing.  Force the migrate
+			 * to fail by clearing migrate flags
+			 */
+			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
+		}
+	}
+
+	if (retval > 0) {
+		unsigned int status;
+
+		if (unlikely(retval != map->m_len)) {
+			ext4_warning(inode->i_sb,
+				     "ES len assertion failed for inode "
+				     "%lu: retval %d != map->m_len %d",
+				     inode->i_ino, retval, map->m_len);
+			WARN_ON(1);
+		}
+
+		/*
+		 * We have to zeroout blocks before inserting them into extent
+		 * status tree. Otherwise someone could look them up there and
+		 * use them before they are really zeroed. We also have to
+		 * unmap metadata before zeroing as otherwise writeback can
+		 * overwrite zeros with stale data from block device.
+		 */
+		if (flags & EXT4_GET_BLOCKS_ZERO &&
+		    map->m_flags & EXT4_MAP_MAPPED &&
+		    map->m_flags & EXT4_MAP_NEW) {
+			ret = ext4_issue_zeroout(inode, map->m_lblk,
+						 map->m_pblk, map->m_len);
+			if (ret) {
+				retval = ret;
+				goto out_sem;
+			}
+		}
+
+		/*
+		 * If the extent has been zeroed out, we don't need to update
+		 * extent status tree.
+		 */
+		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
+		    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
+			if (ext4_es_is_written(&es))
+				goto out_sem;
+		}
+		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
+		    !(status & EXTENT_STATUS_WRITTEN) &&
+		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
+				       map->m_lblk + map->m_len - 1))
+			status |= EXTENT_STATUS_DELAYED;
+		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+					    map->m_pblk, status);
+		if (ret < 0) {
+			retval = ret;
+			goto out_sem;
+		}
+	}
+
+out_sem:
+	up_write((&EXT4_I(inode)->i_data_sem));
+	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
+		ret = check_block_validity(inode, map);
+		if (ret != 0)
+			return ret;
+
+		/*
+		 * Inodes with freshly allocated blocks where contents will be
+		 * visible after transaction commit must be on transaction's
+		 * ordered data list.
+		 */
+		if (map->m_flags & EXT4_MAP_NEW &&
+		    !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
+		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
+		    !ext4_is_quota_file(inode) &&
+		    ext4_should_order_data(inode)) {
+			loff_t start_byte =
+				(loff_t)map->m_lblk << inode->i_blkbits;
+			loff_t length = (loff_t)map->m_len << inode->i_blkbits;
+
+			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
+				ret = ext4_jbd2_inode_add_wait(handle, inode,
+						start_byte, length);
+			else
+				ret = ext4_jbd2_inode_add_write(handle, inode,
+						start_byte, length);
+			if (ret)
+				return ret;
+		}
+	}
+	if (retval > 0 && (map->m_flags & EXT4_MAP_UNWRITTEN ||
+				map->m_flags & EXT4_MAP_MAPPED))
+		ext4_fc_track_range(handle, inode, map->m_lblk,
+					map->m_lblk + map->m_len - 1);
+	if (retval < 0)
+		ext_debug(inode, "failed with err %d\n", retval);
+	return retval;
+}
+
+/*
+ * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
+ * we have to be careful as someone else may be manipulating b_state as well.
+ */
+static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
+{
+	unsigned long old_state;
+	unsigned long new_state;
+
+	flags &= EXT4_MAP_FLAGS;
+
+	/* Dummy buffer_head? Set non-atomically. */
+	if (!bh->b_page) {
+		bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
+		return;
+	}
+	/*
+	 * Someone else may be modifying b_state. Be careful! This is ugly but
+	 * once we get rid of using bh as a container for mapping information
+	 * to pass to / from get_block functions, this can go away.
+	 */
+	do {
+		old_state = READ_ONCE(bh->b_state);
+		new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
+	} while (unlikely(
+		 cmpxchg(&bh->b_state, old_state, new_state) != old_state));
+}
+
+static int _ext4_get_block(struct inode *inode, sector_t iblock,
+			   struct buffer_head *bh, int flags)
+{
+	struct ext4_map_blocks map;
+	int ret = 0;
+
+	if (ext4_has_inline_data(inode))
+		return -ERANGE;
+
+	map.m_lblk = iblock;
+	map.m_len = bh->b_size >> inode->i_blkbits;
+
+	ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
+			      flags);
+	if (ret > 0) {
+		map_bh(bh, inode->i_sb, map.m_pblk);
+		ext4_update_bh_state(bh, map.m_flags);
+		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
+		ret = 0;
+	} else if (ret == 0) {
+		/* hole case, need to fill in bh->b_size */
+		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
+	}
+	return ret;
+}
+
+int ext4_get_block(struct inode *inode, sector_t iblock,
+		   struct buffer_head *bh, int create)
+{
+	return _ext4_get_block(inode, iblock, bh,
+			       create ? EXT4_GET_BLOCKS_CREATE : 0);
+}
+
+/*
+ * Get block function used when preparing for buffered write if we require
+ * creating an unwritten extent if blocks haven't been allocated.  The extent
+ * will be converted to written after the IO is complete.
+ */
+int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
+			     struct buffer_head *bh_result, int create)
+{
+	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
+		   inode->i_ino, create);
+	return _ext4_get_block(inode, iblock, bh_result,
+			       EXT4_GET_BLOCKS_IO_CREATE_EXT);
+}
+
+/* Maximum number of blocks we map for direct IO at once. */
+#define DIO_MAX_BLOCKS 4096
+
+/*
+ * `handle' can be NULL if create is zero
+ */
+struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
+				ext4_lblk_t block, int map_flags)
+{
+	struct ext4_map_blocks map;
+	struct buffer_head *bh;
+	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
+	int err;
+
+	J_ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		 || handle != NULL || create == 0);
+
+	map.m_lblk = block;
+	map.m_len = 1;
+	err = ext4_map_blocks(handle, inode, &map, map_flags);
+
+	if (err == 0)
+		return create ? ERR_PTR(-ENOSPC) : NULL;
+	if (err < 0)
+		return ERR_PTR(err);
+
+	bh = sb_getblk(inode->i_sb, map.m_pblk);
+	if (unlikely(!bh))
+		return ERR_PTR(-ENOMEM);
+	if (map.m_flags & EXT4_MAP_NEW) {
+		J_ASSERT(create != 0);
+		J_ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+			 || (handle != NULL));
+
+		/*
+		 * Now that we do not always journal data, we should
+		 * keep in mind whether this should always journal the
+		 * new buffer as metadata.  For now, regular file
+		 * writes use ext4_get_block instead, so it's not a
+		 * problem.
+		 */
+		lock_buffer(bh);
+		BUFFER_TRACE(bh, "call get_create_access");
+		err = ext4_journal_get_create_access(handle, bh);
+		if (unlikely(err)) {
+			unlock_buffer(bh);
+			goto errout;
+		}
+		if (!buffer_uptodate(bh)) {
+			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
+			set_buffer_uptodate(bh);
+		}
+		unlock_buffer(bh);
+		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+		err = ext4_handle_dirty_metadata(handle, inode, bh);
+		if (unlikely(err))
+			goto errout;
+	} else
+		BUFFER_TRACE(bh, "not a new buffer");
+	return bh;
+errout:
+	brelse(bh);
+	return ERR_PTR(err);
+}
+
+struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
+			       ext4_lblk_t block, int map_flags)
+{
+	struct buffer_head *bh;
+	int ret;
+
+	bh = ext4_getblk(handle, inode, block, map_flags);
+	if (IS_ERR(bh))
+		return bh;
+	if (!bh || ext4_buffer_uptodate(bh))
+		return bh;
+
+	ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
+	if (ret) {
+		put_bh(bh);
+		return ERR_PTR(ret);
+	}
+	return bh;
+}
+
+/* Read a contiguous batch of blocks. */
+int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
+		     bool wait, struct buffer_head **bhs)
+{
+	int i, err;
+
+	for (i = 0; i < bh_count; i++) {
+		bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
+		if (IS_ERR(bhs[i])) {
+			err = PTR_ERR(bhs[i]);
+			bh_count = i;
+			goto out_brelse;
+		}
+	}
+
+	for (i = 0; i < bh_count; i++)
+		/* Note that NULL bhs[i] is valid because of holes. */
+		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
+			ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
+
+	if (!wait)
+		return 0;
+
+	for (i = 0; i < bh_count; i++)
+		if (bhs[i])
+			wait_on_buffer(bhs[i]);
+
+	for (i = 0; i < bh_count; i++) {
+		if (bhs[i] && !buffer_uptodate(bhs[i])) {
+			err = -EIO;
+			goto out_brelse;
+		}
+	}
+	return 0;
+
+out_brelse:
+	for (i = 0; i < bh_count; i++) {
+		brelse(bhs[i]);
+		bhs[i] = NULL;
+	}
+	return err;
+}
+
+int ext4_walk_page_buffers(handle_t *handle,
+			   struct buffer_head *head,
+			   unsigned from,
+			   unsigned to,
+			   int *partial,
+			   int (*fn)(handle_t *handle,
+				     struct buffer_head *bh))
+{
+	struct buffer_head *bh;
+	unsigned block_start, block_end;
+	unsigned blocksize = head->b_size;
+	int err, ret = 0;
+	struct buffer_head *next;
+
+	for (bh = head, block_start = 0;
+	     ret == 0 && (bh != head || !block_start);
+	     block_start = block_end, bh = next) {
+		next = bh->b_this_page;
+		block_end = block_start + blocksize;
+		if (block_end <= from || block_start >= to) {
+			if (partial && !buffer_uptodate(bh))
+				*partial = 1;
+			continue;
+		}
+		err = (*fn)(handle, bh);
+		if (!ret)
+			ret = err;
+	}
+	return ret;
+}
+
+/*
+ * To preserve ordering, it is essential that the hole instantiation and
+ * the data write be encapsulated in a single transaction.  We cannot
+ * close off a transaction and start a new one between the ext4_get_block()
+ * and the commit_write().  So doing the jbd2_journal_start at the start of
+ * prepare_write() is the right place.
+ *
+ * Also, this function can nest inside ext4_writepage().  In that case, we
+ * *know* that ext4_writepage() has generated enough buffer credits to do the
+ * whole page.  So we won't block on the journal in that case, which is good,
+ * because the caller may be PF_MEMALLOC.
+ *
+ * By accident, ext4 can be reentered when a transaction is open via
+ * quota file writes.  If we were to commit the transaction while thus
+ * reentered, there can be a deadlock - we would be holding a quota
+ * lock, and the commit would never complete if another thread had a
+ * transaction open and was blocking on the quota lock - a ranking
+ * violation.
+ *
+ * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
+ * will _not_ run commit under these circumstances because handle->h_ref
+ * is elevated.  We'll still have enough credits for the tiny quotafile
+ * write.
+ */
+int do_journal_get_write_access(handle_t *handle,
+				struct buffer_head *bh)
+{
+	int dirty = buffer_dirty(bh);
+	int ret;
+
+	if (!buffer_mapped(bh) || buffer_freed(bh))
+		return 0;
+	/*
+	 * __block_write_begin() could have dirtied some buffers. Clean
+	 * the dirty bit as jbd2_journal_get_write_access() could complain
+	 * otherwise about fs integrity issues. Setting of the dirty bit
+	 * by __block_write_begin() isn't a real problem here as we clear
+	 * the bit before releasing a page lock and thus writeback cannot
+	 * ever write the buffer.
+	 */
+	if (dirty)
+		clear_buffer_dirty(bh);
+	BUFFER_TRACE(bh, "get write access");
+	ret = ext4_journal_get_write_access(handle, bh);
+	if (!ret && dirty)
+		ret = ext4_handle_dirty_metadata(handle, NULL, bh);
+	return ret;
+}
+
+#ifdef CONFIG_FS_ENCRYPTION
+static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
+				  get_block_t *get_block)
+{
+	unsigned from = pos & (PAGE_SIZE - 1);
+	unsigned to = from + len;
+	struct inode *inode = page->mapping->host;
+	unsigned block_start, block_end;
+	sector_t block;
+	int err = 0;
+	unsigned blocksize = inode->i_sb->s_blocksize;
+	unsigned bbits;
+	struct buffer_head *bh, *head, *wait[2];
+	int nr_wait = 0;
+	int i;
+
+	BUG_ON(!PageLocked(page));
+	BUG_ON(from > PAGE_SIZE);
+	BUG_ON(to > PAGE_SIZE);
+	BUG_ON(from > to);
+
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, blocksize, 0);
+	head = page_buffers(page);
+	bbits = ilog2(blocksize);
+	block = (sector_t)page->index << (PAGE_SHIFT - bbits);
+
+	for (bh = head, block_start = 0; bh != head || !block_start;
+	    block++, block_start = block_end, bh = bh->b_this_page) {
+		block_end = block_start + blocksize;
+		if (block_end <= from || block_start >= to) {
+			if (PageUptodate(page)) {
+				if (!buffer_uptodate(bh))
+					set_buffer_uptodate(bh);
+			}
+			continue;
+		}
+		if (buffer_new(bh))
+			clear_buffer_new(bh);
+		if (!buffer_mapped(bh)) {
+			WARN_ON(bh->b_size != blocksize);
+			err = get_block(inode, block, bh, 1);
+			if (err)
+				break;
+			if (buffer_new(bh)) {
+				if (PageUptodate(page)) {
+					clear_buffer_new(bh);
+					set_buffer_uptodate(bh);
+					mark_buffer_dirty(bh);
+					continue;
+				}
+				if (block_end > to || block_start < from)
+					zero_user_segments(page, to, block_end,
+							   block_start, from);
+				continue;
+			}
+		}
+		if (PageUptodate(page)) {
+			if (!buffer_uptodate(bh))
+				set_buffer_uptodate(bh);
+			continue;
+		}
+		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
+		    !buffer_unwritten(bh) &&
+		    (block_start < from || block_end > to)) {
+			ext4_read_bh_lock(bh, 0, false);
+			wait[nr_wait++] = bh;
+		}
+	}
+	/*
+	 * If we issued read requests, let them complete.
+	 */
+	for (i = 0; i < nr_wait; i++) {
+		wait_on_buffer(wait[i]);
+		if (!buffer_uptodate(wait[i]))
+			err = -EIO;
+	}
+	if (unlikely(err)) {
+		page_zero_new_buffers(page, from, to);
+	} else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
+		for (i = 0; i < nr_wait; i++) {
+			int err2;
+
+			err2 = fscrypt_decrypt_pagecache_blocks(page, blocksize,
+								bh_offset(wait[i]));
+			if (err2) {
+				clear_buffer_uptodate(wait[i]);
+				err = err2;
+			}
+		}
+	}
+
+	return err;
+}
+#endif
+
+static int ext4_write_begin(struct file *file, struct address_space *mapping,
+			    loff_t pos, unsigned len, unsigned flags,
+			    struct page **pagep, void **fsdata)
+{
+	struct inode *inode = mapping->host;
+	int ret, needed_blocks;
+	handle_t *handle;
+	int retries = 0;
+	struct page *page;
+	pgoff_t index;
+	unsigned from, to;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	trace_ext4_write_begin(inode, pos, len, flags);
+	/*
+	 * Reserve one block more for addition to orphan list in case
+	 * we allocate blocks but write fails for some reason
+	 */
+	needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
+	index = pos >> PAGE_SHIFT;
+	from = pos & (PAGE_SIZE - 1);
+	to = from + len;
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
+		ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
+						    flags, pagep);
+		if (ret < 0)
+			return ret;
+		if (ret == 1)
+			return 0;
+	}
+
+	/*
+	 * grab_cache_page_write_begin() can take a long time if the
+	 * system is thrashing due to memory pressure, or if the page
+	 * is being written back.  So grab it first before we start
+	 * the transaction handle.  This also allows us to allocate
+	 * the page (if needed) without using GFP_NOFS.
+	 */
+retry_grab:
+	page = grab_cache_page_write_begin(mapping, index, flags);
+	if (!page)
+		return -ENOMEM;
+	/*
+	 * The same as page allocation, we prealloc buffer heads before
+	 * starting the handle.
+	 */
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, inode->i_sb->s_blocksize, 0);
+
+	unlock_page(page);
+
+retry_journal:
+	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
+	if (IS_ERR(handle)) {
+		put_page(page);
+		return PTR_ERR(handle);
+	}
+
+	lock_page(page);
+	if (page->mapping != mapping) {
+		/* The page got truncated from under us */
+		unlock_page(page);
+		put_page(page);
+		ext4_journal_stop(handle);
+		goto retry_grab;
+	}
+	/* In case writeback began while the page was unlocked */
+	wait_for_stable_page(page);
+
+#ifdef CONFIG_FS_ENCRYPTION
+	if (ext4_should_dioread_nolock(inode))
+		ret = ext4_block_write_begin(page, pos, len,
+					     ext4_get_block_unwritten);
+	else
+		ret = ext4_block_write_begin(page, pos, len,
+					     ext4_get_block);
+#else
+	if (ext4_should_dioread_nolock(inode))
+		ret = __block_write_begin(page, pos, len,
+					  ext4_get_block_unwritten);
+	else
+		ret = __block_write_begin(page, pos, len, ext4_get_block);
+#endif
+	if (!ret && ext4_should_journal_data(inode)) {
+		ret = ext4_walk_page_buffers(handle, page_buffers(page),
+					     from, to, NULL,
+					     do_journal_get_write_access);
+	}
+
+	if (ret) {
+		bool extended = (pos + len > inode->i_size) &&
+				!ext4_verity_in_progress(inode);
+
+		unlock_page(page);
+		/*
+		 * __block_write_begin may have instantiated a few blocks
+		 * outside i_size.  Trim these off again. Don't need
+		 * i_size_read because we hold i_mutex.
+		 *
+		 * Add inode to orphan list in case we crash before
+		 * truncate finishes
+		 */
+		if (extended && ext4_can_truncate(inode))
+			ext4_orphan_add(handle, inode);
+
+		ext4_journal_stop(handle);
+		if (extended) {
+			ext4_truncate_failed_write(inode);
+			/*
+			 * If truncate failed early the inode might
+			 * still be on the orphan list; we need to
+			 * make sure the inode is removed from the
+			 * orphan list in that case.
+			 */
+			if (inode->i_nlink)
+				ext4_orphan_del(NULL, inode);
+		}
+
+		if (ret == -ENOSPC &&
+		    ext4_should_retry_alloc(inode->i_sb, &retries))
+			goto retry_journal;
+		put_page(page);
+		return ret;
+	}
+	*pagep = page;
+	return ret;
+}
+
+/* For write_end() in data=journal mode */
+static int write_end_fn(handle_t *handle, struct buffer_head *bh)
+{
+	int ret;
+	if (!buffer_mapped(bh) || buffer_freed(bh))
+		return 0;
+	set_buffer_uptodate(bh);
+	ret = ext4_handle_dirty_metadata(handle, NULL, bh);
+	clear_buffer_meta(bh);
+	clear_buffer_prio(bh);
+	return ret;
+}
+
+/*
+ * We need to pick up the new inode size which generic_commit_write gave us
+ * `file' can be NULL - eg, when called from page_symlink().
+ *
+ * ext4 never places buffers on inode->i_mapping->private_list.  metadata
+ * buffers are managed internally.
+ */
+static int ext4_write_end(struct file *file,
+			  struct address_space *mapping,
+			  loff_t pos, unsigned len, unsigned copied,
+			  struct page *page, void *fsdata)
+{
+	handle_t *handle = ext4_journal_current_handle();
+	struct inode *inode = mapping->host;
+	loff_t old_size = inode->i_size;
+	int ret = 0, ret2;
+	int i_size_changed = 0;
+	int inline_data = ext4_has_inline_data(inode);
+	bool verity = ext4_verity_in_progress(inode);
+
+	trace_ext4_write_end(inode, pos, len, copied);
+	if (inline_data &&
+	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
+		ret = ext4_write_inline_data_end(inode, pos, len,
+						 copied, page);
+		if (ret < 0) {
+			unlock_page(page);
+			put_page(page);
+			goto errout;
+		}
+		copied = ret;
+		ret = 0;
+	} else
+		copied = block_write_end(file, mapping, pos,
+					 len, copied, page, fsdata);
+	/*
+	 * it's important to update i_size while still holding page lock:
+	 * page writeout could otherwise come in and zero beyond i_size.
+	 *
+	 * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
+	 * blocks are being written past EOF, so skip the i_size update.
+	 */
+	if (!verity)
+		i_size_changed = ext4_update_inode_size(inode, pos + copied);
+	unlock_page(page);
+	put_page(page);
+
+	if (old_size < pos && !verity)
+		pagecache_isize_extended(inode, old_size, pos);
+	/*
+	 * Don't mark the inode dirty under page lock. First, it unnecessarily
+	 * makes the holding time of page lock longer. Second, it forces lock
+	 * ordering of page lock and transaction start for journaling
+	 * filesystems.
+	 */
+	if (i_size_changed || inline_data)
+		ret = ext4_mark_inode_dirty(handle, inode);
+
+errout:
+	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
+		/* if we have allocated more blocks and copied
+		 * less. We will have blocks allocated outside
+		 * inode->i_size. So truncate them
+		 */
+		ext4_orphan_add(handle, inode);
+
+	ret2 = ext4_journal_stop(handle);
+	if (!ret)
+		ret = ret2;
+
+	if (pos + len > inode->i_size && !verity) {
+		ext4_truncate_failed_write(inode);
+		/*
+		 * If truncate failed early the inode might still be
+		 * on the orphan list; we need to make sure the inode
+		 * is removed from the orphan list in that case.
+		 */
+		if (inode->i_nlink)
+			ext4_orphan_del(NULL, inode);
+	}
+
+	return ret ? ret : copied;
+}
+
+/*
+ * This is a private version of page_zero_new_buffers() which doesn't
+ * set the buffer to be dirty, since in data=journalled mode we need
+ * to call ext4_handle_dirty_metadata() instead.
+ */
+static void ext4_journalled_zero_new_buffers(handle_t *handle,
+					    struct page *page,
+					    unsigned from, unsigned to)
+{
+	unsigned int block_start = 0, block_end;
+	struct buffer_head *head, *bh;
+
+	bh = head = page_buffers(page);
+	do {
+		block_end = block_start + bh->b_size;
+		if (buffer_new(bh)) {
+			if (block_end > from && block_start < to) {
+				if (!PageUptodate(page)) {
+					unsigned start, size;
+
+					start = max(from, block_start);
+					size = min(to, block_end) - start;
+
+					zero_user(page, start, size);
+					write_end_fn(handle, bh);
+				}
+				clear_buffer_new(bh);
+			}
+		}
+		block_start = block_end;
+		bh = bh->b_this_page;
+	} while (bh != head);
+}
+
+static int ext4_journalled_write_end(struct file *file,
+				     struct address_space *mapping,
+				     loff_t pos, unsigned len, unsigned copied,
+				     struct page *page, void *fsdata)
+{
+	handle_t *handle = ext4_journal_current_handle();
+	struct inode *inode = mapping->host;
+	loff_t old_size = inode->i_size;
+	int ret = 0, ret2;
+	int partial = 0;
+	unsigned from, to;
+	int size_changed = 0;
+	int inline_data = ext4_has_inline_data(inode);
+	bool verity = ext4_verity_in_progress(inode);
+
+	trace_ext4_journalled_write_end(inode, pos, len, copied);
+	from = pos & (PAGE_SIZE - 1);
+	to = from + len;
+
+	BUG_ON(!ext4_handle_valid(handle));
+
+	if (inline_data) {
+		ret = ext4_write_inline_data_end(inode, pos, len,
+						 copied, page);
+		if (ret < 0) {
+			unlock_page(page);
+			put_page(page);
+			goto errout;
+		}
+		copied = ret;
+		ret = 0;
+	} else if (unlikely(copied < len) && !PageUptodate(page)) {
+		copied = 0;
+		ext4_journalled_zero_new_buffers(handle, page, from, to);
+	} else {
+		if (unlikely(copied < len))
+			ext4_journalled_zero_new_buffers(handle, page,
+							 from + copied, to);
+		ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
+					     from + copied, &partial,
+					     write_end_fn);
+		if (!partial)
+			SetPageUptodate(page);
+	}
+	if (!verity)
+		size_changed = ext4_update_inode_size(inode, pos + copied);
+	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
+	unlock_page(page);
+	put_page(page);
+
+	if (old_size < pos && !verity)
+		pagecache_isize_extended(inode, old_size, pos);
+
+	if (size_changed || inline_data) {
+		ret2 = ext4_mark_inode_dirty(handle, inode);
+		if (!ret)
+			ret = ret2;
+	}
+
+errout:
+	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
+		/* if we have allocated more blocks and copied
+		 * less. We will have blocks allocated outside
+		 * inode->i_size. So truncate them
+		 */
+		ext4_orphan_add(handle, inode);
+
+	ret2 = ext4_journal_stop(handle);
+	if (!ret)
+		ret = ret2;
+	if (pos + len > inode->i_size && !verity) {
+		ext4_truncate_failed_write(inode);
+		/*
+		 * If truncate failed early the inode might still be
+		 * on the orphan list; we need to make sure the inode
+		 * is removed from the orphan list in that case.
+		 */
+		if (inode->i_nlink)
+			ext4_orphan_del(NULL, inode);
+	}
+
+	return ret ? ret : copied;
+}
+
+/*
+ * Reserve space for a single cluster
+ */
+static int ext4_da_reserve_space(struct inode *inode)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	int ret;
+
+	/*
+	 * We will charge metadata quota at writeout time; this saves
+	 * us from metadata over-estimation, though we may go over by
+	 * a small amount in the end.  Here we just reserve for data.
+	 */
+	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
+	if (ret)
+		return ret;
+
+	spin_lock(&ei->i_block_reservation_lock);
+	if (ext4_claim_free_clusters(sbi, 1, 0)) {
+		spin_unlock(&ei->i_block_reservation_lock);
+		dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
+		return -ENOSPC;
+	}
+	ei->i_reserved_data_blocks++;
+	trace_ext4_da_reserve_space(inode);
+	spin_unlock(&ei->i_block_reservation_lock);
+
+	return 0;       /* success */
+}
+
+void ext4_da_release_space(struct inode *inode, int to_free)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!to_free)
+		return;		/* Nothing to release, exit */
+
+	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+
+	trace_ext4_da_release_space(inode, to_free);
+	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
+		/*
+		 * if there aren't enough reserved blocks, then the
+		 * counter is messed up somewhere.  Since this
+		 * function is called from invalidate page, it's
+		 * harmless to return without any action.
+		 */
+		ext4_warning(inode->i_sb, "ext4_da_release_space: "
+			 "ino %lu, to_free %d with only %d reserved "
+			 "data blocks", inode->i_ino, to_free,
+			 ei->i_reserved_data_blocks);
+		WARN_ON(1);
+		to_free = ei->i_reserved_data_blocks;
+	}
+	ei->i_reserved_data_blocks -= to_free;
+
+	/* update fs dirty data blocks counter */
+	percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
+
+	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
+	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
+}
+
+/*
+ * Delayed allocation stuff
+ */
+
+struct mpage_da_data {
+	struct inode *inode;
+	struct writeback_control *wbc;
+
+	pgoff_t first_page;	/* The first page to write */
+	pgoff_t next_page;	/* Current page to examine */
+	pgoff_t last_page;	/* Last page to examine */
+	/*
+	 * Extent to map - this can be after first_page because that can be
+	 * fully mapped. We somewhat abuse m_flags to store whether the extent
+	 * is delalloc or unwritten.
+	 */
+	struct ext4_map_blocks map;
+	struct ext4_io_submit io_submit;	/* IO submission data */
+	unsigned int do_map:1;
+	unsigned int scanned_until_end:1;
+};
+
+static void mpage_release_unused_pages(struct mpage_da_data *mpd,
+				       bool invalidate)
+{
+	int nr_pages, i;
+	pgoff_t index, end;
+	struct pagevec pvec;
+	struct inode *inode = mpd->inode;
+	struct address_space *mapping = inode->i_mapping;
+
+	/* This is necessary when next_page == 0. */
+	if (mpd->first_page >= mpd->next_page)
+		return;
+
+	mpd->scanned_until_end = 0;
+	index = mpd->first_page;
+	end   = mpd->next_page - 1;
+	if (invalidate) {
+		ext4_lblk_t start, last;
+		start = index << (PAGE_SHIFT - inode->i_blkbits);
+		last = end << (PAGE_SHIFT - inode->i_blkbits);
+
+		/*
+		 * avoid racing with extent status tree scans made by
+		 * ext4_insert_delayed_block()
+		 */
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ext4_es_remove_extent(inode, start, last - start + 1);
+		up_write(&EXT4_I(inode)->i_data_sem);
+	}
+
+	pagevec_init(&pvec);
+	while (index <= end) {
+		nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end);
+		if (nr_pages == 0)
+			break;
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			BUG_ON(!PageLocked(page));
+			BUG_ON(PageWriteback(page));
+			if (invalidate) {
+				if (page_mapped(page))
+					clear_page_dirty_for_io(page);
+				block_invalidatepage(page, 0, PAGE_SIZE);
+				ClearPageUptodate(page);
+			}
+			unlock_page(page);
+		}
+		pagevec_release(&pvec);
+	}
+}
+
+static void ext4_print_free_blocks(struct inode *inode)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct super_block *sb = inode->i_sb;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
+	       EXT4_C2B(EXT4_SB(inode->i_sb),
+			ext4_count_free_clusters(sb)));
+	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
+	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
+	       (long long) EXT4_C2B(EXT4_SB(sb),
+		percpu_counter_sum(&sbi->s_freeclusters_counter)));
+	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
+	       (long long) EXT4_C2B(EXT4_SB(sb),
+		percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
+	ext4_msg(sb, KERN_CRIT, "Block reservation details");
+	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
+		 ei->i_reserved_data_blocks);
+	return;
+}
+
+static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
+{
+	return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
+}
+
+/*
+ * ext4_insert_delayed_block - adds a delayed block to the extents status
+ *                             tree, incrementing the reserved cluster/block
+ *                             count or making a pending reservation
+ *                             where needed
+ *
+ * @inode - file containing the newly added block
+ * @lblk - logical block to be added
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int ret;
+	bool allocated = false;
+	bool reserved = false;
+
+	/*
+	 * If the cluster containing lblk is shared with a delayed,
+	 * written, or unwritten extent in a bigalloc file system, it's
+	 * already been accounted for and does not need to be reserved.
+	 * A pending reservation must be made for the cluster if it's
+	 * shared with a written or unwritten extent and doesn't already
+	 * have one.  Written and unwritten extents can be purged from the
+	 * extents status tree if the system is under memory pressure, so
+	 * it's necessary to examine the extent tree if a search of the
+	 * extents status tree doesn't get a match.
+	 */
+	if (sbi->s_cluster_ratio == 1) {
+		ret = ext4_da_reserve_space(inode);
+		if (ret != 0)   /* ENOSPC */
+			goto errout;
+		reserved = true;
+	} else {   /* bigalloc */
+		if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
+			if (!ext4_es_scan_clu(inode,
+					      &ext4_es_is_mapped, lblk)) {
+				ret = ext4_clu_mapped(inode,
+						      EXT4_B2C(sbi, lblk));
+				if (ret < 0)
+					goto errout;
+				if (ret == 0) {
+					ret = ext4_da_reserve_space(inode);
+					if (ret != 0)   /* ENOSPC */
+						goto errout;
+					reserved = true;
+				} else {
+					allocated = true;
+				}
+			} else {
+				allocated = true;
+			}
+		}
+	}
+
+	ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
+	if (ret && reserved)
+		ext4_da_release_space(inode, 1);
+
+errout:
+	return ret;
+}
+
+/*
+ * This function is grabs code from the very beginning of
+ * ext4_map_blocks, but assumes that the caller is from delayed write
+ * time. This function looks up the requested blocks and sets the
+ * buffer delay bit under the protection of i_data_sem.
+ */
+static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
+			      struct ext4_map_blocks *map,
+			      struct buffer_head *bh)
+{
+	struct extent_status es;
+	int retval;
+	sector_t invalid_block = ~((sector_t) 0xffff);
+#ifdef ES_AGGRESSIVE_TEST
+	struct ext4_map_blocks orig_map;
+
+	memcpy(&orig_map, map, sizeof(*map));
+#endif
+
+	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
+		invalid_block = ~0;
+
+	map->m_flags = 0;
+	ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
+		  (unsigned long) map->m_lblk);
+
+	/* Lookup extent status tree firstly */
+	if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
+		if (ext4_es_is_hole(&es)) {
+			retval = 0;
+			down_read(&EXT4_I(inode)->i_data_sem);
+			goto add_delayed;
+		}
+
+		/*
+		 * Delayed extent could be allocated by fallocate.
+		 * So we need to check it.
+		 */
+		if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
+			map_bh(bh, inode->i_sb, invalid_block);
+			set_buffer_new(bh);
+			set_buffer_delay(bh);
+			return 0;
+		}
+
+		map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
+		retval = es.es_len - (iblock - es.es_lblk);
+		if (retval > map->m_len)
+			retval = map->m_len;
+		map->m_len = retval;
+		if (ext4_es_is_written(&es))
+			map->m_flags |= EXT4_MAP_MAPPED;
+		else if (ext4_es_is_unwritten(&es))
+			map->m_flags |= EXT4_MAP_UNWRITTEN;
+		else
+			BUG();
+
+#ifdef ES_AGGRESSIVE_TEST
+		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
+#endif
+		return retval;
+	}
+
+	/*
+	 * Try to see if we can get the block without requesting a new
+	 * file system block.
+	 */
+	down_read(&EXT4_I(inode)->i_data_sem);
+	if (ext4_has_inline_data(inode))
+		retval = 0;
+	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		retval = ext4_ext_map_blocks(NULL, inode, map, 0);
+	else
+		retval = ext4_ind_map_blocks(NULL, inode, map, 0);
+
+add_delayed:
+	if (retval == 0) {
+		int ret;
+
+		/*
+		 * XXX: __block_prepare_write() unmaps passed block,
+		 * is it OK?
+		 */
+
+		ret = ext4_insert_delayed_block(inode, map->m_lblk);
+		if (ret != 0) {
+			retval = ret;
+			goto out_unlock;
+		}
+
+		map_bh(bh, inode->i_sb, invalid_block);
+		set_buffer_new(bh);
+		set_buffer_delay(bh);
+	} else if (retval > 0) {
+		int ret;
+		unsigned int status;
+
+		if (unlikely(retval != map->m_len)) {
+			ext4_warning(inode->i_sb,
+				     "ES len assertion failed for inode "
+				     "%lu: retval %d != map->m_len %d",
+				     inode->i_ino, retval, map->m_len);
+			WARN_ON(1);
+		}
+
+		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+					    map->m_pblk, status);
+		if (ret != 0)
+			retval = ret;
+	}
+
+out_unlock:
+	up_read((&EXT4_I(inode)->i_data_sem));
+
+	return retval;
+}
+
+/*
+ * This is a special get_block_t callback which is used by
+ * ext4_da_write_begin().  It will either return mapped block or
+ * reserve space for a single block.
+ *
+ * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
+ * We also have b_blocknr = -1 and b_bdev initialized properly
+ *
+ * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
+ * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
+ * initialized properly.
+ */
+int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
+			   struct buffer_head *bh, int create)
+{
+	struct ext4_map_blocks map;
+	int ret = 0;
+
+	BUG_ON(create == 0);
+	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
+
+	map.m_lblk = iblock;
+	map.m_len = 1;
+
+	/*
+	 * first, we need to know whether the block is allocated already
+	 * preallocated blocks are unmapped but should treated
+	 * the same as allocated blocks.
+	 */
+	ret = ext4_da_map_blocks(inode, iblock, &map, bh);
+	if (ret <= 0)
+		return ret;
+
+	map_bh(bh, inode->i_sb, map.m_pblk);
+	ext4_update_bh_state(bh, map.m_flags);
+
+	if (buffer_unwritten(bh)) {
+		/* A delayed write to unwritten bh should be marked
+		 * new and mapped.  Mapped ensures that we don't do
+		 * get_block multiple times when we write to the same
+		 * offset and new ensures that we do proper zero out
+		 * for partial write.
+		 */
+		set_buffer_new(bh);
+		set_buffer_mapped(bh);
+	}
+	return 0;
+}
+
+static int bget_one(handle_t *handle, struct buffer_head *bh)
+{
+	get_bh(bh);
+	return 0;
+}
+
+static int bput_one(handle_t *handle, struct buffer_head *bh)
+{
+	put_bh(bh);
+	return 0;
+}
+
+static int __ext4_journalled_writepage(struct page *page,
+				       unsigned int len)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct buffer_head *page_bufs = NULL;
+	handle_t *handle = NULL;
+	int ret = 0, err = 0;
+	int inline_data = ext4_has_inline_data(inode);
+	struct buffer_head *inode_bh = NULL;
+
+	ClearPageChecked(page);
+
+	if (inline_data) {
+		BUG_ON(page->index != 0);
+		BUG_ON(len > ext4_get_max_inline_size(inode));
+		inode_bh = ext4_journalled_write_inline_data(inode, len, page);
+		if (inode_bh == NULL)
+			goto out;
+	} else {
+		page_bufs = page_buffers(page);
+		if (!page_bufs) {
+			BUG();
+			goto out;
+		}
+		ext4_walk_page_buffers(handle, page_bufs, 0, len,
+				       NULL, bget_one);
+	}
+	/*
+	 * We need to release the page lock before we start the
+	 * journal, so grab a reference so the page won't disappear
+	 * out from under us.
+	 */
+	get_page(page);
+	unlock_page(page);
+
+	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
+				    ext4_writepage_trans_blocks(inode));
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		put_page(page);
+		goto out_no_pagelock;
+	}
+	BUG_ON(!ext4_handle_valid(handle));
+
+	lock_page(page);
+	put_page(page);
+	if (page->mapping != mapping) {
+		/* The page got truncated from under us */
+		ext4_journal_stop(handle);
+		ret = 0;
+		goto out;
+	}
+
+	if (inline_data) {
+		ret = ext4_mark_inode_dirty(handle, inode);
+	} else {
+		ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
+					     do_journal_get_write_access);
+
+		err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
+					     write_end_fn);
+	}
+	if (ret == 0)
+		ret = err;
+	err = ext4_jbd2_inode_add_write(handle, inode, page_offset(page), len);
+	if (ret == 0)
+		ret = err;
+	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
+	err = ext4_journal_stop(handle);
+	if (!ret)
+		ret = err;
+
+	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+out:
+	unlock_page(page);
+out_no_pagelock:
+	if (!inline_data && page_bufs)
+		ext4_walk_page_buffers(NULL, page_bufs, 0, len,
+				       NULL, bput_one);
+	brelse(inode_bh);
+	return ret;
+}
+
+/*
+ * Note that we don't need to start a transaction unless we're journaling data
+ * because we should have holes filled from ext4_page_mkwrite(). We even don't
+ * need to file the inode to the transaction's list in ordered mode because if
+ * we are writing back data added by write(), the inode is already there and if
+ * we are writing back data modified via mmap(), no one guarantees in which
+ * transaction the data will hit the disk. In case we are journaling data, we
+ * cannot start transaction directly because transaction start ranks above page
+ * lock so we have to do some magic.
+ *
+ * This function can get called via...
+ *   - ext4_writepages after taking page lock (have journal handle)
+ *   - journal_submit_inode_data_buffers (no journal handle)
+ *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
+ *   - grab_page_cache when doing write_begin (have journal handle)
+ *
+ * We don't do any block allocation in this function. If we have page with
+ * multiple blocks we need to write those buffer_heads that are mapped. This
+ * is important for mmaped based write. So if we do with blocksize 1K
+ * truncate(f, 1024);
+ * a = mmap(f, 0, 4096);
+ * a[0] = 'a';
+ * truncate(f, 4096);
+ * we have in the page first buffer_head mapped via page_mkwrite call back
+ * but other buffer_heads would be unmapped but dirty (dirty done via the
+ * do_wp_page). So writepage should write the first block. If we modify
+ * the mmap area beyond 1024 we will again get a page_fault and the
+ * page_mkwrite callback will do the block allocation and mark the
+ * buffer_heads mapped.
+ *
+ * We redirty the page if we have any buffer_heads that is either delay or
+ * unwritten in the page.
+ *
+ * We can get recursively called as show below.
+ *
+ *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
+ *		ext4_writepage()
+ *
+ * But since we don't do any block allocation we should not deadlock.
+ * Page also have the dirty flag cleared so we don't get recurive page_lock.
+ */
+static int ext4_writepage(struct page *page,
+			  struct writeback_control *wbc)
+{
+	int ret = 0;
+	loff_t size;
+	unsigned int len;
+	struct buffer_head *page_bufs = NULL;
+	struct inode *inode = page->mapping->host;
+	struct ext4_io_submit io_submit;
+	bool keep_towrite = false;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
+		inode->i_mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
+		unlock_page(page);
+		return -EIO;
+	}
+
+	trace_ext4_writepage(page);
+	size = i_size_read(inode);
+	if (page->index == size >> PAGE_SHIFT &&
+	    !ext4_verity_in_progress(inode))
+		len = size & ~PAGE_MASK;
+	else
+		len = PAGE_SIZE;
+
+	/* Should never happen but for bugs in other kernel subsystems */
+	if (!page_has_buffers(page)) {
+		ext4_warning_inode(inode,
+		   "page %lu does not have buffers attached", page->index);
+		ClearPageDirty(page);
+		unlock_page(page);
+		return 0;
+	}
+
+	page_bufs = page_buffers(page);
+	/*
+	 * We cannot do block allocation or other extent handling in this
+	 * function. If there are buffers needing that, we have to redirty
+	 * the page. But we may reach here when we do a journal commit via
+	 * journal_submit_inode_data_buffers() and in that case we must write
+	 * allocated buffers to achieve data=ordered mode guarantees.
+	 *
+	 * Also, if there is only one buffer per page (the fs block
+	 * size == the page size), if one buffer needs block
+	 * allocation or needs to modify the extent tree to clear the
+	 * unwritten flag, we know that the page can't be written at
+	 * all, so we might as well refuse the write immediately.
+	 * Unfortunately if the block size != page size, we can't as
+	 * easily detect this case using ext4_walk_page_buffers(), but
+	 * for the extremely common case, this is an optimization that
+	 * skips a useless round trip through ext4_bio_write_page().
+	 */
+	if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
+				   ext4_bh_delay_or_unwritten)) {
+		redirty_page_for_writepage(wbc, page);
+		if ((current->flags & PF_MEMALLOC) ||
+		    (inode->i_sb->s_blocksize == PAGE_SIZE)) {
+			/*
+			 * For memory cleaning there's no point in writing only
+			 * some buffers. So just bail out. Warn if we came here
+			 * from direct reclaim.
+			 */
+			WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
+							== PF_MEMALLOC);
+			unlock_page(page);
+			return 0;
+		}
+		keep_towrite = true;
+	}
+
+	if (PageChecked(page) && ext4_should_journal_data(inode))
+		/*
+		 * It's mmapped pagecache.  Add buffers and journal it.  There
+		 * doesn't seem much point in redirtying the page here.
+		 */
+		return __ext4_journalled_writepage(page, len);
+
+	ext4_io_submit_init(&io_submit, wbc);
+	io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
+	if (!io_submit.io_end) {
+		redirty_page_for_writepage(wbc, page);
+		unlock_page(page);
+		return -ENOMEM;
+	}
+	ret = ext4_bio_write_page(&io_submit, page, len, wbc, keep_towrite);
+	ext4_io_submit(&io_submit);
+	/* Drop io_end reference we got from init */
+	ext4_put_io_end_defer(io_submit.io_end);
+	return ret;
+}
+
+static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
+{
+	int len;
+	loff_t size;
+	int err;
+
+	BUG_ON(page->index != mpd->first_page);
+	clear_page_dirty_for_io(page);
+	/*
+	 * We have to be very careful here!  Nothing protects writeback path
+	 * against i_size changes and the page can be writeably mapped into
+	 * page tables. So an application can be growing i_size and writing
+	 * data through mmap while writeback runs. clear_page_dirty_for_io()
+	 * write-protects our page in page tables and the page cannot get
+	 * written to again until we release page lock. So only after
+	 * clear_page_dirty_for_io() we are safe to sample i_size for
+	 * ext4_bio_write_page() to zero-out tail of the written page. We rely
+	 * on the barrier provided by TestClearPageDirty in
+	 * clear_page_dirty_for_io() to make sure i_size is really sampled only
+	 * after page tables are updated.
+	 */
+	size = i_size_read(mpd->inode);
+	if (page->index == size >> PAGE_SHIFT &&
+	    !ext4_verity_in_progress(mpd->inode))
+		len = size & ~PAGE_MASK;
+	else
+		len = PAGE_SIZE;
+	err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false);
+	if (!err)
+		mpd->wbc->nr_to_write--;
+	mpd->first_page++;
+
+	return err;
+}
+
+#define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
+
+/*
+ * mballoc gives us at most this number of blocks...
+ * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
+ * The rest of mballoc seems to handle chunks up to full group size.
+ */
+#define MAX_WRITEPAGES_EXTENT_LEN 2048
+
+/*
+ * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
+ *
+ * @mpd - extent of blocks
+ * @lblk - logical number of the block in the file
+ * @bh - buffer head we want to add to the extent
+ *
+ * The function is used to collect contig. blocks in the same state. If the
+ * buffer doesn't require mapping for writeback and we haven't started the
+ * extent of buffers to map yet, the function returns 'true' immediately - the
+ * caller can write the buffer right away. Otherwise the function returns true
+ * if the block has been added to the extent, false if the block couldn't be
+ * added.
+ */
+static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
+				   struct buffer_head *bh)
+{
+	struct ext4_map_blocks *map = &mpd->map;
+
+	/* Buffer that doesn't need mapping for writeback? */
+	if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
+	    (!buffer_delay(bh) && !buffer_unwritten(bh))) {
+		/* So far no extent to map => we write the buffer right away */
+		if (map->m_len == 0)
+			return true;
+		return false;
+	}
+
+	/* First block in the extent? */
+	if (map->m_len == 0) {
+		/* We cannot map unless handle is started... */
+		if (!mpd->do_map)
+			return false;
+		map->m_lblk = lblk;
+		map->m_len = 1;
+		map->m_flags = bh->b_state & BH_FLAGS;
+		return true;
+	}
+
+	/* Don't go larger than mballoc is willing to allocate */
+	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
+		return false;
+
+	/* Can we merge the block to our big extent? */
+	if (lblk == map->m_lblk + map->m_len &&
+	    (bh->b_state & BH_FLAGS) == map->m_flags) {
+		map->m_len++;
+		return true;
+	}
+	return false;
+}
+
+/*
+ * mpage_process_page_bufs - submit page buffers for IO or add them to extent
+ *
+ * @mpd - extent of blocks for mapping
+ * @head - the first buffer in the page
+ * @bh - buffer we should start processing from
+ * @lblk - logical number of the block in the file corresponding to @bh
+ *
+ * Walk through page buffers from @bh upto @head (exclusive) and either submit
+ * the page for IO if all buffers in this page were mapped and there's no
+ * accumulated extent of buffers to map or add buffers in the page to the
+ * extent of buffers to map. The function returns 1 if the caller can continue
+ * by processing the next page, 0 if it should stop adding buffers to the
+ * extent to map because we cannot extend it anymore. It can also return value
+ * < 0 in case of error during IO submission.
+ */
+static int mpage_process_page_bufs(struct mpage_da_data *mpd,
+				   struct buffer_head *head,
+				   struct buffer_head *bh,
+				   ext4_lblk_t lblk)
+{
+	struct inode *inode = mpd->inode;
+	int err;
+	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
+							>> inode->i_blkbits;
+
+	if (ext4_verity_in_progress(inode))
+		blocks = EXT_MAX_BLOCKS;
+
+	do {
+		BUG_ON(buffer_locked(bh));
+
+		if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
+			/* Found extent to map? */
+			if (mpd->map.m_len)
+				return 0;
+			/* Buffer needs mapping and handle is not started? */
+			if (!mpd->do_map)
+				return 0;
+			/* Everything mapped so far and we hit EOF */
+			break;
+		}
+	} while (lblk++, (bh = bh->b_this_page) != head);
+	/* So far everything mapped? Submit the page for IO. */
+	if (mpd->map.m_len == 0) {
+		err = mpage_submit_page(mpd, head->b_page);
+		if (err < 0)
+			return err;
+	}
+	if (lblk >= blocks) {
+		mpd->scanned_until_end = 1;
+		return 0;
+	}
+	return 1;
+}
+
+/*
+ * mpage_process_page - update page buffers corresponding to changed extent and
+ *		       may submit fully mapped page for IO
+ *
+ * @mpd		- description of extent to map, on return next extent to map
+ * @m_lblk	- logical block mapping.
+ * @m_pblk	- corresponding physical mapping.
+ * @map_bh	- determines on return whether this page requires any further
+ *		  mapping or not.
+ * Scan given page buffers corresponding to changed extent and update buffer
+ * state according to new extent state.
+ * We map delalloc buffers to their physical location, clear unwritten bits.
+ * If the given page is not fully mapped, we update @map to the next extent in
+ * the given page that needs mapping & return @map_bh as true.
+ */
+static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
+			      ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
+			      bool *map_bh)
+{
+	struct buffer_head *head, *bh;
+	ext4_io_end_t *io_end = mpd->io_submit.io_end;
+	ext4_lblk_t lblk = *m_lblk;
+	ext4_fsblk_t pblock = *m_pblk;
+	int err = 0;
+	int blkbits = mpd->inode->i_blkbits;
+	ssize_t io_end_size = 0;
+	struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
+
+	bh = head = page_buffers(page);
+	do {
+		if (lblk < mpd->map.m_lblk)
+			continue;
+		if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
+			/*
+			 * Buffer after end of mapped extent.
+			 * Find next buffer in the page to map.
+			 */
+			mpd->map.m_len = 0;
+			mpd->map.m_flags = 0;
+			io_end_vec->size += io_end_size;
+			io_end_size = 0;
+
+			err = mpage_process_page_bufs(mpd, head, bh, lblk);
+			if (err > 0)
+				err = 0;
+			if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
+				io_end_vec = ext4_alloc_io_end_vec(io_end);
+				if (IS_ERR(io_end_vec)) {
+					err = PTR_ERR(io_end_vec);
+					goto out;
+				}
+				io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
+			}
+			*map_bh = true;
+			goto out;
+		}
+		if (buffer_delay(bh)) {
+			clear_buffer_delay(bh);
+			bh->b_blocknr = pblock++;
+		}
+		clear_buffer_unwritten(bh);
+		io_end_size += (1 << blkbits);
+	} while (lblk++, (bh = bh->b_this_page) != head);
+
+	io_end_vec->size += io_end_size;
+	io_end_size = 0;
+	*map_bh = false;
+out:
+	*m_lblk = lblk;
+	*m_pblk = pblock;
+	return err;
+}
+
+/*
+ * mpage_map_buffers - update buffers corresponding to changed extent and
+ *		       submit fully mapped pages for IO
+ *
+ * @mpd - description of extent to map, on return next extent to map
+ *
+ * Scan buffers corresponding to changed extent (we expect corresponding pages
+ * to be already locked) and update buffer state according to new extent state.
+ * We map delalloc buffers to their physical location, clear unwritten bits,
+ * and mark buffers as uninit when we perform writes to unwritten extents
+ * and do extent conversion after IO is finished. If the last page is not fully
+ * mapped, we update @map to the next extent in the last page that needs
+ * mapping. Otherwise we submit the page for IO.
+ */
+static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
+{
+	struct pagevec pvec;
+	int nr_pages, i;
+	struct inode *inode = mpd->inode;
+	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
+	pgoff_t start, end;
+	ext4_lblk_t lblk;
+	ext4_fsblk_t pblock;
+	int err;
+	bool map_bh = false;
+
+	start = mpd->map.m_lblk >> bpp_bits;
+	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
+	lblk = start << bpp_bits;
+	pblock = mpd->map.m_pblk;
+
+	pagevec_init(&pvec);
+	while (start <= end) {
+		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
+						&start, end);
+		if (nr_pages == 0)
+			break;
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			err = mpage_process_page(mpd, page, &lblk, &pblock,
+						 &map_bh);
+			/*
+			 * If map_bh is true, means page may require further bh
+			 * mapping, or maybe the page was submitted for IO.
+			 * So we return to call further extent mapping.
+			 */
+			if (err < 0 || map_bh)
+				goto out;
+			/* Page fully mapped - let IO run! */
+			err = mpage_submit_page(mpd, page);
+			if (err < 0)
+				goto out;
+		}
+		pagevec_release(&pvec);
+	}
+	/* Extent fully mapped and matches with page boundary. We are done. */
+	mpd->map.m_len = 0;
+	mpd->map.m_flags = 0;
+	return 0;
+out:
+	pagevec_release(&pvec);
+	return err;
+}
+
+static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
+{
+	struct inode *inode = mpd->inode;
+	struct ext4_map_blocks *map = &mpd->map;
+	int get_blocks_flags;
+	int err, dioread_nolock;
+
+	trace_ext4_da_write_pages_extent(inode, map);
+	/*
+	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
+	 * to convert an unwritten extent to be initialized (in the case
+	 * where we have written into one or more preallocated blocks).  It is
+	 * possible that we're going to need more metadata blocks than
+	 * previously reserved. However we must not fail because we're in
+	 * writeback and there is nothing we can do about it so it might result
+	 * in data loss.  So use reserved blocks to allocate metadata if
+	 * possible.
+	 *
+	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
+	 * the blocks in question are delalloc blocks.  This indicates
+	 * that the blocks and quotas has already been checked when
+	 * the data was copied into the page cache.
+	 */
+	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
+			   EXT4_GET_BLOCKS_METADATA_NOFAIL |
+			   EXT4_GET_BLOCKS_IO_SUBMIT;
+	dioread_nolock = ext4_should_dioread_nolock(inode);
+	if (dioread_nolock)
+		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
+	if (map->m_flags & BIT(BH_Delay))
+		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
+
+	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
+	if (err < 0)
+		return err;
+	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
+		if (!mpd->io_submit.io_end->handle &&
+		    ext4_handle_valid(handle)) {
+			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
+			handle->h_rsv_handle = NULL;
+		}
+		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
+	}
+
+	BUG_ON(map->m_len == 0);
+	return 0;
+}
+
+/*
+ * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
+ *				 mpd->len and submit pages underlying it for IO
+ *
+ * @handle - handle for journal operations
+ * @mpd - extent to map
+ * @give_up_on_write - we set this to true iff there is a fatal error and there
+ *                     is no hope of writing the data. The caller should discard
+ *                     dirty pages to avoid infinite loops.
+ *
+ * The function maps extent starting at mpd->lblk of length mpd->len. If it is
+ * delayed, blocks are allocated, if it is unwritten, we may need to convert
+ * them to initialized or split the described range from larger unwritten
+ * extent. Note that we need not map all the described range since allocation
+ * can return less blocks or the range is covered by more unwritten extents. We
+ * cannot map more because we are limited by reserved transaction credits. On
+ * the other hand we always make sure that the last touched page is fully
+ * mapped so that it can be written out (and thus forward progress is
+ * guaranteed). After mapping we submit all mapped pages for IO.
+ */
+static int mpage_map_and_submit_extent(handle_t *handle,
+				       struct mpage_da_data *mpd,
+				       bool *give_up_on_write)
+{
+	struct inode *inode = mpd->inode;
+	struct ext4_map_blocks *map = &mpd->map;
+	int err;
+	loff_t disksize;
+	int progress = 0;
+	ext4_io_end_t *io_end = mpd->io_submit.io_end;
+	struct ext4_io_end_vec *io_end_vec;
+
+	io_end_vec = ext4_alloc_io_end_vec(io_end);
+	if (IS_ERR(io_end_vec))
+		return PTR_ERR(io_end_vec);
+	io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
+	do {
+		err = mpage_map_one_extent(handle, mpd);
+		if (err < 0) {
+			struct super_block *sb = inode->i_sb;
+
+			if (ext4_forced_shutdown(EXT4_SB(sb)) ||
+			    ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
+				goto invalidate_dirty_pages;
+			/*
+			 * Let the uper layers retry transient errors.
+			 * In the case of ENOSPC, if ext4_count_free_blocks()
+			 * is non-zero, a commit should free up blocks.
+			 */
+			if ((err == -ENOMEM) ||
+			    (err == -ENOSPC && ext4_count_free_clusters(sb))) {
+				if (progress)
+					goto update_disksize;
+				return err;
+			}
+			ext4_msg(sb, KERN_CRIT,
+				 "Delayed block allocation failed for "
+				 "inode %lu at logical offset %llu with"
+				 " max blocks %u with error %d",
+				 inode->i_ino,
+				 (unsigned long long)map->m_lblk,
+				 (unsigned)map->m_len, -err);
+			ext4_msg(sb, KERN_CRIT,
+				 "This should not happen!! Data will "
+				 "be lost\n");
+			if (err == -ENOSPC)
+				ext4_print_free_blocks(inode);
+		invalidate_dirty_pages:
+			*give_up_on_write = true;
+			return err;
+		}
+		progress = 1;
+		/*
+		 * Update buffer state, submit mapped pages, and get us new
+		 * extent to map
+		 */
+		err = mpage_map_and_submit_buffers(mpd);
+		if (err < 0)
+			goto update_disksize;
+	} while (map->m_len);
+
+update_disksize:
+	/*
+	 * Update on-disk size after IO is submitted.  Races with
+	 * truncate are avoided by checking i_size under i_data_sem.
+	 */
+	disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
+	if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
+		int err2;
+		loff_t i_size;
+
+		down_write(&EXT4_I(inode)->i_data_sem);
+		i_size = i_size_read(inode);
+		if (disksize > i_size)
+			disksize = i_size;
+		if (disksize > EXT4_I(inode)->i_disksize)
+			EXT4_I(inode)->i_disksize = disksize;
+		up_write(&EXT4_I(inode)->i_data_sem);
+		err2 = ext4_mark_inode_dirty(handle, inode);
+		if (err2) {
+			ext4_error_err(inode->i_sb, -err2,
+				       "Failed to mark inode %lu dirty",
+				       inode->i_ino);
+		}
+		if (!err)
+			err = err2;
+	}
+	return err;
+}
+
+/*
+ * Calculate the total number of credits to reserve for one writepages
+ * iteration. This is called from ext4_writepages(). We map an extent of
+ * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
+ * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
+ * bpp - 1 blocks in bpp different extents.
+ */
+static int ext4_da_writepages_trans_blocks(struct inode *inode)
+{
+	int bpp = ext4_journal_blocks_per_page(inode);
+
+	return ext4_meta_trans_blocks(inode,
+				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
+}
+
+/*
+ * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
+ * 				 and underlying extent to map
+ *
+ * @mpd - where to look for pages
+ *
+ * Walk dirty pages in the mapping. If they are fully mapped, submit them for
+ * IO immediately. When we find a page which isn't mapped we start accumulating
+ * extent of buffers underlying these pages that needs mapping (formed by
+ * either delayed or unwritten buffers). We also lock the pages containing
+ * these buffers. The extent found is returned in @mpd structure (starting at
+ * mpd->lblk with length mpd->len blocks).
+ *
+ * Note that this function can attach bios to one io_end structure which are
+ * neither logically nor physically contiguous. Although it may seem as an
+ * unnecessary complication, it is actually inevitable in blocksize < pagesize
+ * case as we need to track IO to all buffers underlying a page in one io_end.
+ */
+static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
+{
+	struct address_space *mapping = mpd->inode->i_mapping;
+	struct pagevec pvec;
+	unsigned int nr_pages;
+	long left = mpd->wbc->nr_to_write;
+	pgoff_t index = mpd->first_page;
+	pgoff_t end = mpd->last_page;
+	xa_mark_t tag;
+	int i, err = 0;
+	int blkbits = mpd->inode->i_blkbits;
+	ext4_lblk_t lblk;
+	struct buffer_head *head;
+
+	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
+		tag = PAGECACHE_TAG_TOWRITE;
+	else
+		tag = PAGECACHE_TAG_DIRTY;
+
+	pagevec_init(&pvec);
+	mpd->map.m_len = 0;
+	mpd->next_page = index;
+	while (index <= end) {
+		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
+				tag);
+		if (nr_pages == 0)
+			break;
+
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			/*
+			 * Accumulated enough dirty pages? This doesn't apply
+			 * to WB_SYNC_ALL mode. For integrity sync we have to
+			 * keep going because someone may be concurrently
+			 * dirtying pages, and we might have synced a lot of
+			 * newly appeared dirty pages, but have not synced all
+			 * of the old dirty pages.
+			 */
+			if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
+				goto out;
+
+			/* If we can't merge this page, we are done. */
+			if (mpd->map.m_len > 0 && mpd->next_page != page->index)
+				goto out;
+
+			lock_page(page);
+			/*
+			 * If the page is no longer dirty, or its mapping no
+			 * longer corresponds to inode we are writing (which
+			 * means it has been truncated or invalidated), or the
+			 * page is already under writeback and we are not doing
+			 * a data integrity writeback, skip the page
+			 */
+			if (!PageDirty(page) ||
+			    (PageWriteback(page) &&
+			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
+			    unlikely(page->mapping != mapping)) {
+				unlock_page(page);
+				continue;
+			}
+
+			wait_on_page_writeback(page);
+			BUG_ON(PageWriteback(page));
+
+			/*
+			 * Should never happen but for buggy code in
+			 * other subsystems that call
+			 * set_page_dirty() without properly warning
+			 * the file system first.  See [1] for more
+			 * information.
+			 *
+			 * [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
+			 */
+			if (!page_has_buffers(page)) {
+				ext4_warning_inode(mpd->inode, "page %lu does not have buffers attached", page->index);
+				ClearPageDirty(page);
+				unlock_page(page);
+				continue;
+			}
+
+			if (mpd->map.m_len == 0)
+				mpd->first_page = page->index;
+			mpd->next_page = page->index + 1;
+			/* Add all dirty buffers to mpd */
+			lblk = ((ext4_lblk_t)page->index) <<
+				(PAGE_SHIFT - blkbits);
+			head = page_buffers(page);
+			err = mpage_process_page_bufs(mpd, head, head, lblk);
+			if (err <= 0)
+				goto out;
+			err = 0;
+			left--;
+		}
+		pagevec_release(&pvec);
+		cond_resched();
+	}
+	mpd->scanned_until_end = 1;
+	return 0;
+out:
+	pagevec_release(&pvec);
+	return err;
+}
+
+static int ext4_writepages(struct address_space *mapping,
+			   struct writeback_control *wbc)
+{
+	pgoff_t	writeback_index = 0;
+	long nr_to_write = wbc->nr_to_write;
+	int range_whole = 0;
+	int cycled = 1;
+	handle_t *handle = NULL;
+	struct mpage_da_data mpd;
+	struct inode *inode = mapping->host;
+	int needed_blocks, rsv_blocks = 0, ret = 0;
+	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
+	struct blk_plug plug;
+	bool give_up_on_write = false;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	percpu_down_read(&sbi->s_writepages_rwsem);
+	trace_ext4_writepages(inode, wbc);
+
+	/*
+	 * No pages to write? This is mainly a kludge to avoid starting
+	 * a transaction for special inodes like journal inode on last iput()
+	 * because that could violate lock ordering on umount
+	 */
+	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
+		goto out_writepages;
+
+	if (ext4_should_journal_data(inode)) {
+		ret = generic_writepages(mapping, wbc);
+		goto out_writepages;
+	}
+
+	/*
+	 * If the filesystem has aborted, it is read-only, so return
+	 * right away instead of dumping stack traces later on that
+	 * will obscure the real source of the problem.  We test
+	 * EXT4_MF_FS_ABORTED instead of sb->s_flag's SB_RDONLY because
+	 * the latter could be true if the filesystem is mounted
+	 * read-only, and in that case, ext4_writepages should
+	 * *never* be called, so if that ever happens, we would want
+	 * the stack trace.
+	 */
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(mapping->host->i_sb)) ||
+		     ext4_test_mount_flag(inode->i_sb, EXT4_MF_FS_ABORTED))) {
+		ret = -EROFS;
+		goto out_writepages;
+	}
+
+	/*
+	 * If we have inline data and arrive here, it means that
+	 * we will soon create the block for the 1st page, so
+	 * we'd better clear the inline data here.
+	 */
+	if (ext4_has_inline_data(inode)) {
+		/* Just inode will be modified... */
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			goto out_writepages;
+		}
+		BUG_ON(ext4_test_inode_state(inode,
+				EXT4_STATE_MAY_INLINE_DATA));
+		ext4_destroy_inline_data(handle, inode);
+		ext4_journal_stop(handle);
+	}
+
+	if (ext4_should_dioread_nolock(inode)) {
+		/*
+		 * We may need to convert up to one extent per block in
+		 * the page and we may dirty the inode.
+		 */
+		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
+						PAGE_SIZE >> inode->i_blkbits);
+	}
+
+	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+		range_whole = 1;
+
+	if (wbc->range_cyclic) {
+		writeback_index = mapping->writeback_index;
+		if (writeback_index)
+			cycled = 0;
+		mpd.first_page = writeback_index;
+		mpd.last_page = -1;
+	} else {
+		mpd.first_page = wbc->range_start >> PAGE_SHIFT;
+		mpd.last_page = wbc->range_end >> PAGE_SHIFT;
+	}
+
+	mpd.inode = inode;
+	mpd.wbc = wbc;
+	ext4_io_submit_init(&mpd.io_submit, wbc);
+retry:
+	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
+		tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
+	blk_start_plug(&plug);
+
+	/*
+	 * First writeback pages that don't need mapping - we can avoid
+	 * starting a transaction unnecessarily and also avoid being blocked
+	 * in the block layer on device congestion while having transaction
+	 * started.
+	 */
+	mpd.do_map = 0;
+	mpd.scanned_until_end = 0;
+	mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
+	if (!mpd.io_submit.io_end) {
+		ret = -ENOMEM;
+		goto unplug;
+	}
+	ret = mpage_prepare_extent_to_map(&mpd);
+	/* Unlock pages we didn't use */
+	mpage_release_unused_pages(&mpd, false);
+	/* Submit prepared bio */
+	ext4_io_submit(&mpd.io_submit);
+	ext4_put_io_end_defer(mpd.io_submit.io_end);
+	mpd.io_submit.io_end = NULL;
+	if (ret < 0)
+		goto unplug;
+
+	while (!mpd.scanned_until_end && wbc->nr_to_write > 0) {
+		/* For each extent of pages we use new io_end */
+		mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
+		if (!mpd.io_submit.io_end) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		/*
+		 * We have two constraints: We find one extent to map and we
+		 * must always write out whole page (makes a difference when
+		 * blocksize < pagesize) so that we don't block on IO when we
+		 * try to write out the rest of the page. Journalled mode is
+		 * not supported by delalloc.
+		 */
+		BUG_ON(ext4_should_journal_data(inode));
+		needed_blocks = ext4_da_writepages_trans_blocks(inode);
+
+		/* start a new transaction */
+		handle = ext4_journal_start_with_reserve(inode,
+				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
+			       "%ld pages, ino %lu; err %d", __func__,
+				wbc->nr_to_write, inode->i_ino, ret);
+			/* Release allocated io_end */
+			ext4_put_io_end(mpd.io_submit.io_end);
+			mpd.io_submit.io_end = NULL;
+			break;
+		}
+		mpd.do_map = 1;
+
+		trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
+		ret = mpage_prepare_extent_to_map(&mpd);
+		if (!ret && mpd.map.m_len)
+			ret = mpage_map_and_submit_extent(handle, &mpd,
+					&give_up_on_write);
+		/*
+		 * Caution: If the handle is synchronous,
+		 * ext4_journal_stop() can wait for transaction commit
+		 * to finish which may depend on writeback of pages to
+		 * complete or on page lock to be released.  In that
+		 * case, we have to wait until after we have
+		 * submitted all the IO, released page locks we hold,
+		 * and dropped io_end reference (for extent conversion
+		 * to be able to complete) before stopping the handle.
+		 */
+		if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
+			ext4_journal_stop(handle);
+			handle = NULL;
+			mpd.do_map = 0;
+		}
+		/* Unlock pages we didn't use */
+		mpage_release_unused_pages(&mpd, give_up_on_write);
+		/* Submit prepared bio */
+		ext4_io_submit(&mpd.io_submit);
+
+		/*
+		 * Drop our io_end reference we got from init. We have
+		 * to be careful and use deferred io_end finishing if
+		 * we are still holding the transaction as we can
+		 * release the last reference to io_end which may end
+		 * up doing unwritten extent conversion.
+		 */
+		if (handle) {
+			ext4_put_io_end_defer(mpd.io_submit.io_end);
+			ext4_journal_stop(handle);
+		} else
+			ext4_put_io_end(mpd.io_submit.io_end);
+		mpd.io_submit.io_end = NULL;
+
+		if (ret == -ENOSPC && sbi->s_journal) {
+			/*
+			 * Commit the transaction which would
+			 * free blocks released in the transaction
+			 * and try again
+			 */
+			jbd2_journal_force_commit_nested(sbi->s_journal);
+			ret = 0;
+			continue;
+		}
+		/* Fatal error - ENOMEM, EIO... */
+		if (ret)
+			break;
+	}
+unplug:
+	blk_finish_plug(&plug);
+	if (!ret && !cycled && wbc->nr_to_write > 0) {
+		cycled = 1;
+		mpd.last_page = writeback_index - 1;
+		mpd.first_page = 0;
+		goto retry;
+	}
+
+	/* Update index */
+	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+		/*
+		 * Set the writeback_index so that range_cyclic
+		 * mode will write it back later
+		 */
+		mapping->writeback_index = mpd.first_page;
+
+out_writepages:
+	trace_ext4_writepages_result(inode, wbc, ret,
+				     nr_to_write - wbc->nr_to_write);
+	percpu_up_read(&sbi->s_writepages_rwsem);
+	return ret;
+}
+
+static int ext4_dax_writepages(struct address_space *mapping,
+			       struct writeback_control *wbc)
+{
+	int ret;
+	long nr_to_write = wbc->nr_to_write;
+	struct inode *inode = mapping->host;
+	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	percpu_down_read(&sbi->s_writepages_rwsem);
+	trace_ext4_writepages(inode, wbc);
+
+	ret = dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
+	trace_ext4_writepages_result(inode, wbc, ret,
+				     nr_to_write - wbc->nr_to_write);
+	percpu_up_read(&sbi->s_writepages_rwsem);
+	return ret;
+}
+
+static int ext4_nonda_switch(struct super_block *sb)
+{
+	s64 free_clusters, dirty_clusters;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	/*
+	 * switch to non delalloc mode if we are running low
+	 * on free block. The free block accounting via percpu
+	 * counters can get slightly wrong with percpu_counter_batch getting
+	 * accumulated on each CPU without updating global counters
+	 * Delalloc need an accurate free block accounting. So switch
+	 * to non delalloc when we are near to error range.
+	 */
+	free_clusters =
+		percpu_counter_read_positive(&sbi->s_freeclusters_counter);
+	dirty_clusters =
+		percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
+	/*
+	 * Start pushing delalloc when 1/2 of free blocks are dirty.
+	 */
+	if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
+		try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
+
+	if (2 * free_clusters < 3 * dirty_clusters ||
+	    free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
+		/*
+		 * free block count is less than 150% of dirty blocks
+		 * or free blocks is less than watermark
+		 */
+		return 1;
+	}
+	return 0;
+}
+
+/* We always reserve for an inode update; the superblock could be there too */
+static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
+{
+	if (likely(ext4_has_feature_large_file(inode->i_sb)))
+		return 1;
+
+	if (pos + len <= 0x7fffffffULL)
+		return 1;
+
+	/* We might need to update the superblock to set LARGE_FILE */
+	return 2;
+}
+
+static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
+			       loff_t pos, unsigned len, unsigned flags,
+			       struct page **pagep, void **fsdata)
+{
+	int ret, retries = 0;
+	struct page *page;
+	pgoff_t index;
+	struct inode *inode = mapping->host;
+	handle_t *handle;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	index = pos >> PAGE_SHIFT;
+
+	if (ext4_nonda_switch(inode->i_sb) || S_ISLNK(inode->i_mode) ||
+	    ext4_verity_in_progress(inode)) {
+		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
+		return ext4_write_begin(file, mapping, pos,
+					len, flags, pagep, fsdata);
+	}
+	*fsdata = (void *)0;
+	trace_ext4_da_write_begin(inode, pos, len, flags);
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
+		ret = ext4_da_write_inline_data_begin(mapping, inode,
+						      pos, len, flags,
+						      pagep, fsdata);
+		if (ret < 0)
+			return ret;
+		if (ret == 1)
+			return 0;
+	}
+
+	/*
+	 * grab_cache_page_write_begin() can take a long time if the
+	 * system is thrashing due to memory pressure, or if the page
+	 * is being written back.  So grab it first before we start
+	 * the transaction handle.  This also allows us to allocate
+	 * the page (if needed) without using GFP_NOFS.
+	 */
+retry_grab:
+	page = grab_cache_page_write_begin(mapping, index, flags);
+	if (!page)
+		return -ENOMEM;
+	unlock_page(page);
+
+	/*
+	 * With delayed allocation, we don't log the i_disksize update
+	 * if there is delayed block allocation. But we still need
+	 * to journalling the i_disksize update if writes to the end
+	 * of file which has an already mapped buffer.
+	 */
+retry_journal:
+	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
+				ext4_da_write_credits(inode, pos, len));
+	if (IS_ERR(handle)) {
+		put_page(page);
+		return PTR_ERR(handle);
+	}
+
+	lock_page(page);
+	if (page->mapping != mapping) {
+		/* The page got truncated from under us */
+		unlock_page(page);
+		put_page(page);
+		ext4_journal_stop(handle);
+		goto retry_grab;
+	}
+	/* In case writeback began while the page was unlocked */
+	wait_for_stable_page(page);
+
+#ifdef CONFIG_FS_ENCRYPTION
+	ret = ext4_block_write_begin(page, pos, len,
+				     ext4_da_get_block_prep);
+#else
+	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
+#endif
+	if (ret < 0) {
+		unlock_page(page);
+		ext4_journal_stop(handle);
+		/*
+		 * block_write_begin may have instantiated a few blocks
+		 * outside i_size.  Trim these off again. Don't need
+		 * i_size_read because we hold i_mutex.
+		 */
+		if (pos + len > inode->i_size)
+			ext4_truncate_failed_write(inode);
+
+		if (ret == -ENOSPC &&
+		    ext4_should_retry_alloc(inode->i_sb, &retries))
+			goto retry_journal;
+
+		put_page(page);
+		return ret;
+	}
+
+	*pagep = page;
+	return ret;
+}
+
+/*
+ * Check if we should update i_disksize
+ * when write to the end of file but not require block allocation
+ */
+static int ext4_da_should_update_i_disksize(struct page *page,
+					    unsigned long offset)
+{
+	struct buffer_head *bh;
+	struct inode *inode = page->mapping->host;
+	unsigned int idx;
+	int i;
+
+	bh = page_buffers(page);
+	idx = offset >> inode->i_blkbits;
+
+	for (i = 0; i < idx; i++)
+		bh = bh->b_this_page;
+
+	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
+		return 0;
+	return 1;
+}
+
+static int ext4_da_write_end(struct file *file,
+			     struct address_space *mapping,
+			     loff_t pos, unsigned len, unsigned copied,
+			     struct page *page, void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	int ret = 0, ret2;
+	handle_t *handle = ext4_journal_current_handle();
+	loff_t new_i_size;
+	unsigned long start, end;
+	int write_mode = (int)(unsigned long)fsdata;
+
+	if (write_mode == FALL_BACK_TO_NONDELALLOC)
+		return ext4_write_end(file, mapping, pos,
+				      len, copied, page, fsdata);
+
+	trace_ext4_da_write_end(inode, pos, len, copied);
+	start = pos & (PAGE_SIZE - 1);
+	end = start + copied - 1;
+
+	/*
+	 * Since we are holding inode lock, we are sure i_disksize <=
+	 * i_size. We also know that if i_disksize < i_size, there are
+	 * delalloc writes pending in the range upto i_size. If the end of
+	 * the current write is <= i_size, there's no need to touch
+	 * i_disksize since writeback will push i_disksize upto i_size
+	 * eventually. If the end of the current write is > i_size and
+	 * inside an allocated block (ext4_da_should_update_i_disksize()
+	 * check), we need to update i_disksize here as neither
+	 * ext4_writepage() nor certain ext4_writepages() paths not
+	 * allocating blocks update i_disksize.
+	 *
+	 * Note that we defer inode dirtying to generic_write_end() /
+	 * ext4_da_write_inline_data_end().
+	 */
+	new_i_size = pos + copied;
+	if (copied && new_i_size > inode->i_size) {
+		if (ext4_has_inline_data(inode) ||
+		    ext4_da_should_update_i_disksize(page, end))
+			ext4_update_i_disksize(inode, new_i_size);
+	}
+
+	if (write_mode != CONVERT_INLINE_DATA &&
+	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
+	    ext4_has_inline_data(inode))
+		ret = ext4_da_write_inline_data_end(inode, pos, len, copied,
+						     page);
+	else
+		ret = generic_write_end(file, mapping, pos, len, copied,
+							page, fsdata);
+
+	copied = ret;
+	ret2 = ext4_journal_stop(handle);
+	if (unlikely(ret2 && !ret))
+		ret = ret2;
+
+	return ret ? ret : copied;
+}
+
+/*
+ * Force all delayed allocation blocks to be allocated for a given inode.
+ */
+int ext4_alloc_da_blocks(struct inode *inode)
+{
+	trace_ext4_alloc_da_blocks(inode);
+
+	if (!EXT4_I(inode)->i_reserved_data_blocks)
+		return 0;
+
+	/*
+	 * We do something simple for now.  The filemap_flush() will
+	 * also start triggering a write of the data blocks, which is
+	 * not strictly speaking necessary (and for users of
+	 * laptop_mode, not even desirable).  However, to do otherwise
+	 * would require replicating code paths in:
+	 *
+	 * ext4_writepages() ->
+	 *    write_cache_pages() ---> (via passed in callback function)
+	 *        __mpage_da_writepage() -->
+	 *           mpage_add_bh_to_extent()
+	 *           mpage_da_map_blocks()
+	 *
+	 * The problem is that write_cache_pages(), located in
+	 * mm/page-writeback.c, marks pages clean in preparation for
+	 * doing I/O, which is not desirable if we're not planning on
+	 * doing I/O at all.
+	 *
+	 * We could call write_cache_pages(), and then redirty all of
+	 * the pages by calling redirty_page_for_writepage() but that
+	 * would be ugly in the extreme.  So instead we would need to
+	 * replicate parts of the code in the above functions,
+	 * simplifying them because we wouldn't actually intend to
+	 * write out the pages, but rather only collect contiguous
+	 * logical block extents, call the multi-block allocator, and
+	 * then update the buffer heads with the block allocations.
+	 *
+	 * For now, though, we'll cheat by calling filemap_flush(),
+	 * which will map the blocks, and start the I/O, but not
+	 * actually wait for the I/O to complete.
+	 */
+	return filemap_flush(inode->i_mapping);
+}
+
+/*
+ * bmap() is special.  It gets used by applications such as lilo and by
+ * the swapper to find the on-disk block of a specific piece of data.
+ *
+ * Naturally, this is dangerous if the block concerned is still in the
+ * journal.  If somebody makes a swapfile on an ext4 data-journaling
+ * filesystem and enables swap, then they may get a nasty shock when the
+ * data getting swapped to that swapfile suddenly gets overwritten by
+ * the original zero's written out previously to the journal and
+ * awaiting writeback in the kernel's buffer cache.
+ *
+ * So, if we see any bmap calls here on a modified, data-journaled file,
+ * take extra steps to flush any blocks which might be in the cache.
+ */
+static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
+{
+	struct inode *inode = mapping->host;
+	journal_t *journal;
+	sector_t ret = 0;
+	int err;
+
+	inode_lock_shared(inode);
+	/*
+	 * We can get here for an inline file via the FIBMAP ioctl
+	 */
+	if (ext4_has_inline_data(inode))
+		goto out;
+
+	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
+			test_opt(inode->i_sb, DELALLOC)) {
+		/*
+		 * With delalloc we want to sync the file
+		 * so that we can make sure we allocate
+		 * blocks for file
+		 */
+		filemap_write_and_wait(mapping);
+	}
+
+	if (EXT4_JOURNAL(inode) &&
+	    ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
+		/*
+		 * This is a REALLY heavyweight approach, but the use of
+		 * bmap on dirty files is expected to be extremely rare:
+		 * only if we run lilo or swapon on a freshly made file
+		 * do we expect this to happen.
+		 *
+		 * (bmap requires CAP_SYS_RAWIO so this does not
+		 * represent an unprivileged user DOS attack --- we'd be
+		 * in trouble if mortal users could trigger this path at
+		 * will.)
+		 *
+		 * NB. EXT4_STATE_JDATA is not set on files other than
+		 * regular files.  If somebody wants to bmap a directory
+		 * or symlink and gets confused because the buffer
+		 * hasn't yet been flushed to disk, they deserve
+		 * everything they get.
+		 */
+
+		ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
+		journal = EXT4_JOURNAL(inode);
+		jbd2_journal_lock_updates(journal);
+		err = jbd2_journal_flush(journal);
+		jbd2_journal_unlock_updates(journal);
+
+		if (err)
+			goto out;
+	}
+
+	ret = iomap_bmap(mapping, block, &ext4_iomap_ops);
+
+out:
+	inode_unlock_shared(inode);
+	return ret;
+}
+
+static int ext4_readpage(struct file *file, struct page *page)
+{
+	int ret = -EAGAIN;
+	struct inode *inode = page->mapping->host;
+
+	trace_ext4_readpage(page);
+
+	if (ext4_has_inline_data(inode))
+		ret = ext4_readpage_inline(inode, page);
+
+	if (ret == -EAGAIN)
+		return ext4_mpage_readpages(inode, NULL, page);
+
+	return ret;
+}
+
+static void ext4_readahead(struct readahead_control *rac)
+{
+	struct inode *inode = rac->mapping->host;
+
+	/* If the file has inline data, no need to do readahead. */
+	if (ext4_has_inline_data(inode))
+		return;
+
+	ext4_mpage_readpages(inode, rac, NULL);
+}
+
+static void ext4_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length)
+{
+	trace_ext4_invalidatepage(page, offset, length);
+
+	/* No journalling happens on data buffers when this function is used */
+	WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
+
+	block_invalidatepage(page, offset, length);
+}
+
+static int __ext4_journalled_invalidatepage(struct page *page,
+					    unsigned int offset,
+					    unsigned int length)
+{
+	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
+
+	trace_ext4_journalled_invalidatepage(page, offset, length);
+
+	/*
+	 * If it's a full truncate we just forget about the pending dirtying
+	 */
+	if (offset == 0 && length == PAGE_SIZE)
+		ClearPageChecked(page);
+
+	return jbd2_journal_invalidatepage(journal, page, offset, length);
+}
+
+/* Wrapper for aops... */
+static void ext4_journalled_invalidatepage(struct page *page,
+					   unsigned int offset,
+					   unsigned int length)
+{
+	WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
+}
+
+static int ext4_releasepage(struct page *page, gfp_t wait)
+{
+	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
+
+	trace_ext4_releasepage(page);
+
+	/* Page has dirty journalled data -> cannot release */
+	if (PageChecked(page))
+		return 0;
+	if (journal)
+		return jbd2_journal_try_to_free_buffers(journal, page);
+	else
+		return try_to_free_buffers(page);
+}
+
+static bool ext4_inode_datasync_dirty(struct inode *inode)
+{
+	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+
+	if (journal) {
+		if (jbd2_transaction_committed(journal,
+			EXT4_I(inode)->i_datasync_tid))
+			return false;
+		if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
+			return !list_empty(&EXT4_I(inode)->i_fc_list);
+		return true;
+	}
+
+	/* Any metadata buffers to write? */
+	if (!list_empty(&inode->i_mapping->private_list))
+		return true;
+	return inode->i_state & I_DIRTY_DATASYNC;
+}
+
+static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
+			   struct ext4_map_blocks *map, loff_t offset,
+			   loff_t length)
+{
+	u8 blkbits = inode->i_blkbits;
+
+	/*
+	 * Writes that span EOF might trigger an I/O size update on completion,
+	 * so consider them to be dirty for the purpose of O_DSYNC, even if
+	 * there is no other metadata changes being made or are pending.
+	 */
+	iomap->flags = 0;
+	if (ext4_inode_datasync_dirty(inode) ||
+	    offset + length > i_size_read(inode))
+		iomap->flags |= IOMAP_F_DIRTY;
+
+	if (map->m_flags & EXT4_MAP_NEW)
+		iomap->flags |= IOMAP_F_NEW;
+
+	iomap->bdev = inode->i_sb->s_bdev;
+	iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
+	iomap->offset = (u64) map->m_lblk << blkbits;
+	iomap->length = (u64) map->m_len << blkbits;
+
+	if ((map->m_flags & EXT4_MAP_MAPPED) &&
+	    !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		iomap->flags |= IOMAP_F_MERGED;
+
+	/*
+	 * Flags passed to ext4_map_blocks() for direct I/O writes can result
+	 * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
+	 * set. In order for any allocated unwritten extents to be converted
+	 * into written extents correctly within the ->end_io() handler, we
+	 * need to ensure that the iomap->type is set appropriately. Hence, the
+	 * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
+	 * been set first.
+	 */
+	if (map->m_flags & EXT4_MAP_UNWRITTEN) {
+		iomap->type = IOMAP_UNWRITTEN;
+		iomap->addr = (u64) map->m_pblk << blkbits;
+	} else if (map->m_flags & EXT4_MAP_MAPPED) {
+		iomap->type = IOMAP_MAPPED;
+		iomap->addr = (u64) map->m_pblk << blkbits;
+	} else {
+		iomap->type = IOMAP_HOLE;
+		iomap->addr = IOMAP_NULL_ADDR;
+	}
+}
+
+static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
+			    unsigned int flags)
+{
+	handle_t *handle;
+	u8 blkbits = inode->i_blkbits;
+	int ret, dio_credits, m_flags = 0, retries = 0;
+
+	/*
+	 * Trim the mapping request to the maximum value that we can map at
+	 * once for direct I/O.
+	 */
+	if (map->m_len > DIO_MAX_BLOCKS)
+		map->m_len = DIO_MAX_BLOCKS;
+	dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
+
+retry:
+	/*
+	 * Either we allocate blocks and then don't get an unwritten extent, so
+	 * in that case we have reserved enough credits. Or, the blocks are
+	 * already allocated and unwritten. In that case, the extent conversion
+	 * fits into the credits as well.
+	 */
+	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	/*
+	 * DAX and direct I/O are the only two operations that are currently
+	 * supported with IOMAP_WRITE.
+	 */
+	WARN_ON(!IS_DAX(inode) && !(flags & IOMAP_DIRECT));
+	if (IS_DAX(inode))
+		m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
+	/*
+	 * We use i_size instead of i_disksize here because delalloc writeback
+	 * can complete at any point during the I/O and subsequently push the
+	 * i_disksize out to i_size. This could be beyond where direct I/O is
+	 * happening and thus expose allocated blocks to direct I/O reads.
+	 */
+	else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
+		m_flags = EXT4_GET_BLOCKS_CREATE;
+	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
+
+	ret = ext4_map_blocks(handle, inode, map, m_flags);
+
+	/*
+	 * We cannot fill holes in indirect tree based inodes as that could
+	 * expose stale data in the case of a crash. Use the magic error code
+	 * to fallback to buffered I/O.
+	 */
+	if (!m_flags && !ret)
+		ret = -ENOTBLK;
+
+	ext4_journal_stop(handle);
+	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+
+	return ret;
+}
+
+
+static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+		unsigned flags, struct iomap *iomap, struct iomap *srcmap)
+{
+	int ret;
+	struct ext4_map_blocks map;
+	u8 blkbits = inode->i_blkbits;
+
+	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
+		return -ERANGE;
+
+	/*
+	 * Calculate the first and last logical blocks respectively.
+	 */
+	map.m_lblk = offset >> blkbits;
+	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
+			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
+
+	if (flags & IOMAP_WRITE) {
+		/*
+		 * We check here if the blocks are already allocated, then we
+		 * don't need to start a journal txn and we can directly return
+		 * the mapping information. This could boost performance
+		 * especially in multi-threaded overwrite requests.
+		 */
+		if (offset + length <= i_size_read(inode)) {
+			ret = ext4_map_blocks(NULL, inode, &map, 0);
+			if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
+				goto out;
+		}
+		ret = ext4_iomap_alloc(inode, &map, flags);
+	} else {
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+	}
+
+	if (ret < 0)
+		return ret;
+out:
+	ext4_set_iomap(inode, iomap, &map, offset, length);
+
+	return 0;
+}
+
+static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
+		loff_t length, unsigned flags, struct iomap *iomap,
+		struct iomap *srcmap)
+{
+	int ret;
+
+	/*
+	 * Even for writes we don't need to allocate blocks, so just pretend
+	 * we are reading to save overhead of starting a transaction.
+	 */
+	flags &= ~IOMAP_WRITE;
+	ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
+	WARN_ON_ONCE(!ret && iomap->type != IOMAP_MAPPED);
+	return ret;
+}
+
+static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
+			  ssize_t written, unsigned flags, struct iomap *iomap)
+{
+	/*
+	 * Check to see whether an error occurred while writing out the data to
+	 * the allocated blocks. If so, return the magic error code so that we
+	 * fallback to buffered I/O and attempt to complete the remainder of
+	 * the I/O. Any blocks that may have been allocated in preparation for
+	 * the direct I/O will be reused during buffered I/O.
+	 */
+	if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
+		return -ENOTBLK;
+
+	return 0;
+}
+
+const struct iomap_ops ext4_iomap_ops = {
+	.iomap_begin		= ext4_iomap_begin,
+	.iomap_end		= ext4_iomap_end,
+};
+
+const struct iomap_ops ext4_iomap_overwrite_ops = {
+	.iomap_begin		= ext4_iomap_overwrite_begin,
+	.iomap_end		= ext4_iomap_end,
+};
+
+static bool ext4_iomap_is_delalloc(struct inode *inode,
+				   struct ext4_map_blocks *map)
+{
+	struct extent_status es;
+	ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1;
+
+	ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
+				  map->m_lblk, end, &es);
+
+	if (!es.es_len || es.es_lblk > end)
+		return false;
+
+	if (es.es_lblk > map->m_lblk) {
+		map->m_len = es.es_lblk - map->m_lblk;
+		return false;
+	}
+
+	offset = map->m_lblk - es.es_lblk;
+	map->m_len = es.es_len - offset;
+
+	return true;
+}
+
+static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
+				   loff_t length, unsigned int flags,
+				   struct iomap *iomap, struct iomap *srcmap)
+{
+	int ret;
+	bool delalloc = false;
+	struct ext4_map_blocks map;
+	u8 blkbits = inode->i_blkbits;
+
+	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
+		return -EINVAL;
+
+	if (ext4_has_inline_data(inode)) {
+		ret = ext4_inline_data_iomap(inode, iomap);
+		if (ret != -EAGAIN) {
+			if (ret == 0 && offset >= iomap->length)
+				ret = -ENOENT;
+			return ret;
+		}
+	}
+
+	/*
+	 * Calculate the first and last logical block respectively.
+	 */
+	map.m_lblk = offset >> blkbits;
+	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
+			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
+
+	/*
+	 * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
+	 * So handle it here itself instead of querying ext4_map_blocks().
+	 * Since ext4_map_blocks() will warn about it and will return
+	 * -EIO error.
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+		if (offset >= sbi->s_bitmap_maxbytes) {
+			map.m_flags = 0;
+			goto set_iomap;
+		}
+	}
+
+	ret = ext4_map_blocks(NULL, inode, &map, 0);
+	if (ret < 0)
+		return ret;
+	if (ret == 0)
+		delalloc = ext4_iomap_is_delalloc(inode, &map);
+
+set_iomap:
+	ext4_set_iomap(inode, iomap, &map, offset, length);
+	if (delalloc && iomap->type == IOMAP_HOLE)
+		iomap->type = IOMAP_DELALLOC;
+
+	return 0;
+}
+
+const struct iomap_ops ext4_iomap_report_ops = {
+	.iomap_begin = ext4_iomap_begin_report,
+};
+
+/*
+ * Pages can be marked dirty completely asynchronously from ext4's journalling
+ * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
+ * much here because ->set_page_dirty is called under VFS locks.  The page is
+ * not necessarily locked.
+ *
+ * We cannot just dirty the page and leave attached buffers clean, because the
+ * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
+ * or jbddirty because all the journalling code will explode.
+ *
+ * So what we do is to mark the page "pending dirty" and next time writepage
+ * is called, propagate that into the buffers appropriately.
+ */
+static int ext4_journalled_set_page_dirty(struct page *page)
+{
+	SetPageChecked(page);
+	return __set_page_dirty_nobuffers(page);
+}
+
+static int ext4_set_page_dirty(struct page *page)
+{
+	WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page));
+	WARN_ON_ONCE(!page_has_buffers(page));
+	return __set_page_dirty_buffers(page);
+}
+
+static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
+				    struct file *file, sector_t *span)
+{
+	return iomap_swapfile_activate(sis, file, span,
+				       &ext4_iomap_report_ops);
+}
+
+static const struct address_space_operations ext4_aops = {
+	.readpage		= ext4_readpage,
+	.readahead		= ext4_readahead,
+	.writepage		= ext4_writepage,
+	.writepages		= ext4_writepages,
+	.write_begin		= ext4_write_begin,
+	.write_end		= ext4_write_end,
+	.set_page_dirty		= ext4_set_page_dirty,
+	.bmap			= ext4_bmap,
+	.invalidatepage		= ext4_invalidatepage,
+	.releasepage		= ext4_releasepage,
+	.direct_IO		= noop_direct_IO,
+	.migratepage		= buffer_migrate_page,
+	.is_partially_uptodate  = block_is_partially_uptodate,
+	.error_remove_page	= generic_error_remove_page,
+	.swap_activate		= ext4_iomap_swap_activate,
+};
+
+static const struct address_space_operations ext4_journalled_aops = {
+	.readpage		= ext4_readpage,
+	.readahead		= ext4_readahead,
+	.writepage		= ext4_writepage,
+	.writepages		= ext4_writepages,
+	.write_begin		= ext4_write_begin,
+	.write_end		= ext4_journalled_write_end,
+	.set_page_dirty		= ext4_journalled_set_page_dirty,
+	.bmap			= ext4_bmap,
+	.invalidatepage		= ext4_journalled_invalidatepage,
+	.releasepage		= ext4_releasepage,
+	.direct_IO		= noop_direct_IO,
+	.is_partially_uptodate  = block_is_partially_uptodate,
+	.error_remove_page	= generic_error_remove_page,
+	.swap_activate		= ext4_iomap_swap_activate,
+};
+
+static const struct address_space_operations ext4_da_aops = {
+	.readpage		= ext4_readpage,
+	.readahead		= ext4_readahead,
+	.writepage		= ext4_writepage,
+	.writepages		= ext4_writepages,
+	.write_begin		= ext4_da_write_begin,
+	.write_end		= ext4_da_write_end,
+	.set_page_dirty		= ext4_set_page_dirty,
+	.bmap			= ext4_bmap,
+	.invalidatepage		= ext4_invalidatepage,
+	.releasepage		= ext4_releasepage,
+	.direct_IO		= noop_direct_IO,
+	.migratepage		= buffer_migrate_page,
+	.is_partially_uptodate  = block_is_partially_uptodate,
+	.error_remove_page	= generic_error_remove_page,
+	.swap_activate		= ext4_iomap_swap_activate,
+};
+
+static const struct address_space_operations ext4_dax_aops = {
+	.writepages		= ext4_dax_writepages,
+	.direct_IO		= noop_direct_IO,
+	.set_page_dirty		= noop_set_page_dirty,
+	.bmap			= ext4_bmap,
+	.invalidatepage		= noop_invalidatepage,
+	.swap_activate		= ext4_iomap_swap_activate,
+};
+
+void ext4_set_aops(struct inode *inode)
+{
+	switch (ext4_inode_journal_mode(inode)) {
+	case EXT4_INODE_ORDERED_DATA_MODE:
+	case EXT4_INODE_WRITEBACK_DATA_MODE:
+		break;
+	case EXT4_INODE_JOURNAL_DATA_MODE:
+		inode->i_mapping->a_ops = &ext4_journalled_aops;
+		return;
+	default:
+		BUG();
+	}
+	if (IS_DAX(inode))
+		inode->i_mapping->a_ops = &ext4_dax_aops;
+	else if (test_opt(inode->i_sb, DELALLOC))
+		inode->i_mapping->a_ops = &ext4_da_aops;
+	else
+		inode->i_mapping->a_ops = &ext4_aops;
+}
+
+static int __ext4_block_zero_page_range(handle_t *handle,
+		struct address_space *mapping, loff_t from, loff_t length)
+{
+	ext4_fsblk_t index = from >> PAGE_SHIFT;
+	unsigned offset = from & (PAGE_SIZE-1);
+	unsigned blocksize, pos;
+	ext4_lblk_t iblock;
+	struct inode *inode = mapping->host;
+	struct buffer_head *bh;
+	struct page *page;
+	int err = 0;
+
+	page = find_or_create_page(mapping, from >> PAGE_SHIFT,
+				   mapping_gfp_constraint(mapping, ~__GFP_FS));
+	if (!page)
+		return -ENOMEM;
+
+	blocksize = inode->i_sb->s_blocksize;
+
+	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
+
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, blocksize, 0);
+
+	/* Find the buffer that contains "offset" */
+	bh = page_buffers(page);
+	pos = blocksize;
+	while (offset >= pos) {
+		bh = bh->b_this_page;
+		iblock++;
+		pos += blocksize;
+	}
+	if (buffer_freed(bh)) {
+		BUFFER_TRACE(bh, "freed: skip");
+		goto unlock;
+	}
+	if (!buffer_mapped(bh)) {
+		BUFFER_TRACE(bh, "unmapped");
+		ext4_get_block(inode, iblock, bh, 0);
+		/* unmapped? It's a hole - nothing to do */
+		if (!buffer_mapped(bh)) {
+			BUFFER_TRACE(bh, "still unmapped");
+			goto unlock;
+		}
+	}
+
+	/* Ok, it's mapped. Make sure it's up-to-date */
+	if (PageUptodate(page))
+		set_buffer_uptodate(bh);
+
+	if (!buffer_uptodate(bh)) {
+		err = ext4_read_bh_lock(bh, 0, true);
+		if (err)
+			goto unlock;
+		if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
+			/* We expect the key to be set. */
+			BUG_ON(!fscrypt_has_encryption_key(inode));
+			err = fscrypt_decrypt_pagecache_blocks(page, blocksize,
+							       bh_offset(bh));
+			if (err) {
+				clear_buffer_uptodate(bh);
+				goto unlock;
+			}
+		}
+	}
+	if (ext4_should_journal_data(inode)) {
+		BUFFER_TRACE(bh, "get write access");
+		err = ext4_journal_get_write_access(handle, bh);
+		if (err)
+			goto unlock;
+	}
+	zero_user(page, offset, length);
+	BUFFER_TRACE(bh, "zeroed end of block");
+
+	if (ext4_should_journal_data(inode)) {
+		err = ext4_handle_dirty_metadata(handle, inode, bh);
+	} else {
+		err = 0;
+		mark_buffer_dirty(bh);
+		if (ext4_should_order_data(inode))
+			err = ext4_jbd2_inode_add_write(handle, inode, from,
+					length);
+	}
+
+unlock:
+	unlock_page(page);
+	put_page(page);
+	return err;
+}
+
+/*
+ * ext4_block_zero_page_range() zeros out a mapping of length 'length'
+ * starting from file offset 'from'.  The range to be zero'd must
+ * be contained with in one block.  If the specified range exceeds
+ * the end of the block it will be shortened to end of the block
+ * that corresponds to 'from'
+ */
+static int ext4_block_zero_page_range(handle_t *handle,
+		struct address_space *mapping, loff_t from, loff_t length)
+{
+	struct inode *inode = mapping->host;
+	unsigned offset = from & (PAGE_SIZE-1);
+	unsigned blocksize = inode->i_sb->s_blocksize;
+	unsigned max = blocksize - (offset & (blocksize - 1));
+
+	/*
+	 * correct length if it does not fall between
+	 * 'from' and the end of the block
+	 */
+	if (length > max || length < 0)
+		length = max;
+
+	if (IS_DAX(inode)) {
+		return iomap_zero_range(inode, from, length, NULL,
+					&ext4_iomap_ops);
+	}
+	return __ext4_block_zero_page_range(handle, mapping, from, length);
+}
+
+/*
+ * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
+ * up to the end of the block which corresponds to `from'.
+ * This required during truncate. We need to physically zero the tail end
+ * of that block so it doesn't yield old data if the file is later grown.
+ */
+static int ext4_block_truncate_page(handle_t *handle,
+		struct address_space *mapping, loff_t from)
+{
+	unsigned offset = from & (PAGE_SIZE-1);
+	unsigned length;
+	unsigned blocksize;
+	struct inode *inode = mapping->host;
+
+	/* If we are processing an encrypted inode during orphan list handling */
+	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
+		return 0;
+
+	blocksize = inode->i_sb->s_blocksize;
+	length = blocksize - (offset & (blocksize - 1));
+
+	return ext4_block_zero_page_range(handle, mapping, from, length);
+}
+
+int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
+			     loff_t lstart, loff_t length)
+{
+	struct super_block *sb = inode->i_sb;
+	struct address_space *mapping = inode->i_mapping;
+	unsigned partial_start, partial_end;
+	ext4_fsblk_t start, end;
+	loff_t byte_end = (lstart + length - 1);
+	int err = 0;
+
+	partial_start = lstart & (sb->s_blocksize - 1);
+	partial_end = byte_end & (sb->s_blocksize - 1);
+
+	start = lstart >> sb->s_blocksize_bits;
+	end = byte_end >> sb->s_blocksize_bits;
+
+	/* Handle partial zero within the single block */
+	if (start == end &&
+	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
+		err = ext4_block_zero_page_range(handle, mapping,
+						 lstart, length);
+		return err;
+	}
+	/* Handle partial zero out on the start of the range */
+	if (partial_start) {
+		err = ext4_block_zero_page_range(handle, mapping,
+						 lstart, sb->s_blocksize);
+		if (err)
+			return err;
+	}
+	/* Handle partial zero out on the end of the range */
+	if (partial_end != sb->s_blocksize - 1)
+		err = ext4_block_zero_page_range(handle, mapping,
+						 byte_end - partial_end,
+						 partial_end + 1);
+	return err;
+}
+
+int ext4_can_truncate(struct inode *inode)
+{
+	if (S_ISREG(inode->i_mode))
+		return 1;
+	if (S_ISDIR(inode->i_mode))
+		return 1;
+	if (S_ISLNK(inode->i_mode))
+		return !ext4_inode_is_fast_symlink(inode);
+	return 0;
+}
+
+/*
+ * We have to make sure i_disksize gets properly updated before we truncate
+ * page cache due to hole punching or zero range. Otherwise i_disksize update
+ * can get lost as it may have been postponed to submission of writeback but
+ * that will never happen after we truncate page cache.
+ */
+int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
+				      loff_t len)
+{
+	handle_t *handle;
+	int ret;
+
+	loff_t size = i_size_read(inode);
+
+	WARN_ON(!inode_is_locked(inode));
+	if (offset > size || offset + len < size)
+		return 0;
+
+	if (EXT4_I(inode)->i_disksize >= size)
+		return 0;
+
+	handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ext4_update_i_disksize(inode, size);
+	ret = ext4_mark_inode_dirty(handle, inode);
+	ext4_journal_stop(handle);
+
+	return ret;
+}
+
+static void ext4_wait_dax_page(struct ext4_inode_info *ei)
+{
+	up_write(&ei->i_mmap_sem);
+	schedule();
+	down_write(&ei->i_mmap_sem);
+}
+
+int ext4_break_layouts(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct page *page;
+	int error;
+
+	if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem)))
+		return -EINVAL;
+
+	do {
+		page = dax_layout_busy_page(inode->i_mapping);
+		if (!page)
+			return 0;
+
+		error = ___wait_var_event(&page->_refcount,
+				atomic_read(&page->_refcount) == 1,
+				TASK_INTERRUPTIBLE, 0, 0,
+				ext4_wait_dax_page(ei));
+	} while (error == 0);
+
+	return error;
+}
+
+/*
+ * ext4_punch_hole: punches a hole in a file by releasing the blocks
+ * associated with the given offset and length
+ *
+ * @inode:  File inode
+ * @offset: The offset where the hole will begin
+ * @len:    The length of the hole
+ *
+ * Returns: 0 on success or negative on failure
+ */
+
+int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
+{
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	ext4_lblk_t first_block, stop_block;
+	struct address_space *mapping = inode->i_mapping;
+	loff_t first_block_offset, last_block_offset, max_length;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	handle_t *handle;
+	unsigned int credits;
+	int ret = 0, ret2 = 0;
+
+	trace_ext4_punch_hole(inode, offset, length, 0);
+
+	/*
+	 * Write out all dirty pages to avoid race conditions
+	 * Then release them.
+	 */
+	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
+		ret = filemap_write_and_wait_range(mapping, offset,
+						   offset + length - 1);
+		if (ret)
+			return ret;
+	}
+
+	inode_lock(inode);
+
+	/* No need to punch hole beyond i_size */
+	if (offset >= inode->i_size)
+		goto out_mutex;
+
+	/*
+	 * If the hole extends beyond i_size, set the hole
+	 * to end after the page that contains i_size
+	 */
+	if (offset + length > inode->i_size) {
+		length = inode->i_size +
+		   PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
+		   offset;
+	}
+
+	/*
+	 * For punch hole the length + offset needs to be within one block
+	 * before last range. Adjust the length if it goes beyond that limit.
+	 */
+	max_length = sbi->s_bitmap_maxbytes - inode->i_sb->s_blocksize;
+	if (offset + length > max_length)
+		length = max_length - offset;
+
+	if (offset & (sb->s_blocksize - 1) ||
+	    (offset + length) & (sb->s_blocksize - 1)) {
+		/*
+		 * Attach jinode to inode for jbd2 if we do any zeroing of
+		 * partial block
+		 */
+		ret = ext4_inode_attach_jinode(inode);
+		if (ret < 0)
+			goto out_mutex;
+
+	}
+
+	/* Wait all existing dio workers, newcomers will block on i_mutex */
+	inode_dio_wait(inode);
+
+	ret = file_modified(file);
+	if (ret)
+		goto out_mutex;
+
+	/*
+	 * Prevent page faults from reinstantiating pages we have released from
+	 * page cache.
+	 */
+	down_write(&EXT4_I(inode)->i_mmap_sem);
+
+	ret = ext4_break_layouts(inode);
+	if (ret)
+		goto out_dio;
+
+	first_block_offset = round_up(offset, sb->s_blocksize);
+	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
+
+	/* Now release the pages and zero block aligned part of pages*/
+	if (last_block_offset > first_block_offset) {
+		ret = ext4_update_disksize_before_punch(inode, offset, length);
+		if (ret)
+			goto out_dio;
+		truncate_pagecache_range(inode, first_block_offset,
+					 last_block_offset);
+	}
+
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		credits = ext4_writepage_trans_blocks(inode);
+	else
+		credits = ext4_blocks_for_truncate(inode);
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		ext4_std_error(sb, ret);
+		goto out_dio;
+	}
+
+	ret = ext4_zero_partial_blocks(handle, inode, offset,
+				       length);
+	if (ret)
+		goto out_stop;
+
+	first_block = (offset + sb->s_blocksize - 1) >>
+		EXT4_BLOCK_SIZE_BITS(sb);
+	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
+
+	/* If there are blocks to remove, do it */
+	if (stop_block > first_block) {
+
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ext4_discard_preallocations(inode, 0);
+
+		ret = ext4_es_remove_extent(inode, first_block,
+					    stop_block - first_block);
+		if (ret) {
+			up_write(&EXT4_I(inode)->i_data_sem);
+			goto out_stop;
+		}
+
+		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+			ret = ext4_ext_remove_space(inode, first_block,
+						    stop_block - 1);
+		else
+			ret = ext4_ind_remove_space(handle, inode, first_block,
+						    stop_block);
+
+		up_write(&EXT4_I(inode)->i_data_sem);
+	}
+	ext4_fc_track_range(handle, inode, first_block, stop_block);
+	if (IS_SYNC(inode))
+		ext4_handle_sync(handle);
+
+	inode->i_mtime = inode->i_ctime = current_time(inode);
+	ret2 = ext4_mark_inode_dirty(handle, inode);
+	if (unlikely(ret2))
+		ret = ret2;
+	if (ret >= 0)
+		ext4_update_inode_fsync_trans(handle, inode, 1);
+out_stop:
+	ext4_journal_stop(handle);
+out_dio:
+	up_write(&EXT4_I(inode)->i_mmap_sem);
+out_mutex:
+	inode_unlock(inode);
+	return ret;
+}
+
+int ext4_inode_attach_jinode(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct jbd2_inode *jinode;
+
+	if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
+		return 0;
+
+	jinode = jbd2_alloc_inode(GFP_KERNEL);
+	spin_lock(&inode->i_lock);
+	if (!ei->jinode) {
+		if (!jinode) {
+			spin_unlock(&inode->i_lock);
+			return -ENOMEM;
+		}
+		ei->jinode = jinode;
+		jbd2_journal_init_jbd_inode(ei->jinode, inode);
+		jinode = NULL;
+	}
+	spin_unlock(&inode->i_lock);
+	if (unlikely(jinode != NULL))
+		jbd2_free_inode(jinode);
+	return 0;
+}
+
+/*
+ * ext4_truncate()
+ *
+ * We block out ext4_get_block() block instantiations across the entire
+ * transaction, and VFS/VM ensures that ext4_truncate() cannot run
+ * simultaneously on behalf of the same inode.
+ *
+ * As we work through the truncate and commit bits of it to the journal there
+ * is one core, guiding principle: the file's tree must always be consistent on
+ * disk.  We must be able to restart the truncate after a crash.
+ *
+ * The file's tree may be transiently inconsistent in memory (although it
+ * probably isn't), but whenever we close off and commit a journal transaction,
+ * the contents of (the filesystem + the journal) must be consistent and
+ * restartable.  It's pretty simple, really: bottom up, right to left (although
+ * left-to-right works OK too).
+ *
+ * Note that at recovery time, journal replay occurs *before* the restart of
+ * truncate against the orphan inode list.
+ *
+ * The committed inode has the new, desired i_size (which is the same as
+ * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
+ * that this inode's truncate did not complete and it will again call
+ * ext4_truncate() to have another go.  So there will be instantiated blocks
+ * to the right of the truncation point in a crashed ext4 filesystem.  But
+ * that's fine - as long as they are linked from the inode, the post-crash
+ * ext4_truncate() run will find them and release them.
+ */
+int ext4_truncate(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	unsigned int credits;
+	int err = 0, err2;
+	handle_t *handle;
+	struct address_space *mapping = inode->i_mapping;
+
+	/*
+	 * There is a possibility that we're either freeing the inode
+	 * or it's a completely new inode. In those cases we might not
+	 * have i_mutex locked because it's not necessary.
+	 */
+	if (!(inode->i_state & (I_NEW|I_FREEING)))
+		WARN_ON(!inode_is_locked(inode));
+	trace_ext4_truncate_enter(inode);
+
+	if (!ext4_can_truncate(inode))
+		goto out_trace;
+
+	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
+		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
+
+	if (ext4_has_inline_data(inode)) {
+		int has_inline = 1;
+
+		err = ext4_inline_data_truncate(inode, &has_inline);
+		if (err || has_inline)
+			goto out_trace;
+	}
+
+	/* If we zero-out tail of the page, we have to create jinode for jbd2 */
+	if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
+		err = ext4_inode_attach_jinode(inode);
+		if (err)
+			goto out_trace;
+	}
+
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		credits = ext4_writepage_trans_blocks(inode);
+	else
+		credits = ext4_blocks_for_truncate(inode);
+
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		goto out_trace;
+	}
+
+	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
+		ext4_block_truncate_page(handle, mapping, inode->i_size);
+
+	/*
+	 * We add the inode to the orphan list, so that if this
+	 * truncate spans multiple transactions, and we crash, we will
+	 * resume the truncate when the filesystem recovers.  It also
+	 * marks the inode dirty, to catch the new size.
+	 *
+	 * Implication: the file must always be in a sane, consistent
+	 * truncatable state while each transaction commits.
+	 */
+	err = ext4_orphan_add(handle, inode);
+	if (err)
+		goto out_stop;
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+
+	ext4_discard_preallocations(inode, 0);
+
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		err = ext4_ext_truncate(handle, inode);
+	else
+		ext4_ind_truncate(handle, inode);
+
+	up_write(&ei->i_data_sem);
+	if (err)
+		goto out_stop;
+
+	if (IS_SYNC(inode))
+		ext4_handle_sync(handle);
+
+out_stop:
+	/*
+	 * If this was a simple ftruncate() and the file will remain alive,
+	 * then we need to clear up the orphan record which we created above.
+	 * However, if this was a real unlink then we were called by
+	 * ext4_evict_inode(), and we allow that function to clean up the
+	 * orphan info for us.
+	 */
+	if (inode->i_nlink)
+		ext4_orphan_del(handle, inode);
+
+	inode->i_mtime = inode->i_ctime = current_time(inode);
+	err2 = ext4_mark_inode_dirty(handle, inode);
+	if (unlikely(err2 && !err))
+		err = err2;
+	ext4_journal_stop(handle);
+
+out_trace:
+	trace_ext4_truncate_exit(inode);
+	return err;
+}
+
+/*
+ * ext4_get_inode_loc returns with an extra refcount against the inode's
+ * underlying buffer_head on success. If 'in_mem' is true, we have all
+ * data in memory that is needed to recreate the on-disk version of this
+ * inode.
+ */
+static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
+				struct ext4_iloc *iloc, int in_mem,
+				ext4_fsblk_t *ret_block)
+{
+	struct ext4_group_desc	*gdp;
+	struct buffer_head	*bh;
+	ext4_fsblk_t		block;
+	struct blk_plug		plug;
+	int			inodes_per_block, inode_offset;
+
+	iloc->bh = NULL;
+	if (ino < EXT4_ROOT_INO ||
+	    ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
+		return -EFSCORRUPTED;
+
+	iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
+	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
+	if (!gdp)
+		return -EIO;
+
+	/*
+	 * Figure out the offset within the block group inode table
+	 */
+	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
+	inode_offset = ((ino - 1) %
+			EXT4_INODES_PER_GROUP(sb));
+	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
+
+	block = ext4_inode_table(sb, gdp);
+	if ((block <= le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) ||
+	    (block >= ext4_blocks_count(EXT4_SB(sb)->s_es))) {
+		ext4_error(sb, "Invalid inode table block %llu in "
+			   "block_group %u", block, iloc->block_group);
+		return -EFSCORRUPTED;
+	}
+	block += (inode_offset / inodes_per_block);
+
+	bh = sb_getblk(sb, block);
+	if (unlikely(!bh))
+		return -ENOMEM;
+	if (ext4_simulate_fail(sb, EXT4_SIM_INODE_EIO))
+		goto simulate_eio;
+	if (!buffer_uptodate(bh)) {
+		lock_buffer(bh);
+
+		if (ext4_buffer_uptodate(bh)) {
+			/* someone brought it uptodate while we waited */
+			unlock_buffer(bh);
+			goto has_buffer;
+		}
+
+		/*
+		 * If we have all information of the inode in memory and this
+		 * is the only valid inode in the block, we need not read the
+		 * block.
+		 */
+		if (in_mem) {
+			struct buffer_head *bitmap_bh;
+			int i, start;
+
+			start = inode_offset & ~(inodes_per_block - 1);
+
+			/* Is the inode bitmap in cache? */
+			bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
+			if (unlikely(!bitmap_bh))
+				goto make_io;
+
+			/*
+			 * If the inode bitmap isn't in cache then the
+			 * optimisation may end up performing two reads instead
+			 * of one, so skip it.
+			 */
+			if (!buffer_uptodate(bitmap_bh)) {
+				brelse(bitmap_bh);
+				goto make_io;
+			}
+			for (i = start; i < start + inodes_per_block; i++) {
+				if (i == inode_offset)
+					continue;
+				if (ext4_test_bit(i, bitmap_bh->b_data))
+					break;
+			}
+			brelse(bitmap_bh);
+			if (i == start + inodes_per_block) {
+				/* all other inodes are free, so skip I/O */
+				memset(bh->b_data, 0, bh->b_size);
+				set_buffer_uptodate(bh);
+				unlock_buffer(bh);
+				goto has_buffer;
+			}
+		}
+
+make_io:
+		/*
+		 * If we need to do any I/O, try to pre-readahead extra
+		 * blocks from the inode table.
+		 */
+		blk_start_plug(&plug);
+		if (EXT4_SB(sb)->s_inode_readahead_blks) {
+			ext4_fsblk_t b, end, table;
+			unsigned num;
+			__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
+
+			table = ext4_inode_table(sb, gdp);
+			/* s_inode_readahead_blks is always a power of 2 */
+			b = block & ~((ext4_fsblk_t) ra_blks - 1);
+			if (table > b)
+				b = table;
+			end = b + ra_blks;
+			num = EXT4_INODES_PER_GROUP(sb);
+			if (ext4_has_group_desc_csum(sb))
+				num -= ext4_itable_unused_count(sb, gdp);
+			table += num / inodes_per_block;
+			if (end > table)
+				end = table;
+			while (b <= end)
+				ext4_sb_breadahead_unmovable(sb, b++);
+		}
+
+		/*
+		 * There are other valid inodes in the buffer, this inode
+		 * has in-inode xattrs, or we don't have this inode in memory.
+		 * Read the block from disk.
+		 */
+		trace_ext4_load_inode(sb, ino);
+		ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
+		blk_finish_plug(&plug);
+		wait_on_buffer(bh);
+		if (!buffer_uptodate(bh)) {
+		simulate_eio:
+			if (ret_block)
+				*ret_block = block;
+			brelse(bh);
+			return -EIO;
+		}
+	}
+has_buffer:
+	iloc->bh = bh;
+	return 0;
+}
+
+static int __ext4_get_inode_loc_noinmem(struct inode *inode,
+					struct ext4_iloc *iloc)
+{
+	ext4_fsblk_t err_blk = 0;
+	int ret;
+
+	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, 0,
+					&err_blk);
+
+	if (ret == -EIO)
+		ext4_error_inode_block(inode, err_blk, EIO,
+					"unable to read itable block");
+
+	return ret;
+}
+
+int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
+{
+	ext4_fsblk_t err_blk = 0;
+	int ret;
+
+	/* We have all inode data except xattrs in memory here. */
+	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc,
+		!ext4_test_inode_state(inode, EXT4_STATE_XATTR), &err_blk);
+
+	if (ret == -EIO)
+		ext4_error_inode_block(inode, err_blk, EIO,
+					"unable to read itable block");
+
+	return ret;
+}
+
+
+int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
+			  struct ext4_iloc *iloc)
+{
+	return __ext4_get_inode_loc(sb, ino, iloc, 0, NULL);
+}
+
+static bool ext4_should_enable_dax(struct inode *inode)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+	if (test_opt2(inode->i_sb, DAX_NEVER))
+		return false;
+	if (!S_ISREG(inode->i_mode))
+		return false;
+	if (ext4_should_journal_data(inode))
+		return false;
+	if (ext4_has_inline_data(inode))
+		return false;
+	if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
+		return false;
+	if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
+		return false;
+	if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
+		return false;
+	if (test_opt(inode->i_sb, DAX_ALWAYS))
+		return true;
+
+	return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
+}
+
+void ext4_set_inode_flags(struct inode *inode, bool init)
+{
+	unsigned int flags = EXT4_I(inode)->i_flags;
+	unsigned int new_fl = 0;
+
+	WARN_ON_ONCE(IS_DAX(inode) && init);
+
+	if (flags & EXT4_SYNC_FL)
+		new_fl |= S_SYNC;
+	if (flags & EXT4_APPEND_FL)
+		new_fl |= S_APPEND;
+	if (flags & EXT4_IMMUTABLE_FL)
+		new_fl |= S_IMMUTABLE;
+	if (flags & EXT4_NOATIME_FL)
+		new_fl |= S_NOATIME;
+	if (flags & EXT4_DIRSYNC_FL)
+		new_fl |= S_DIRSYNC;
+
+	/* Because of the way inode_set_flags() works we must preserve S_DAX
+	 * here if already set. */
+	new_fl |= (inode->i_flags & S_DAX);
+	if (init && ext4_should_enable_dax(inode))
+		new_fl |= S_DAX;
+
+	if (flags & EXT4_ENCRYPT_FL)
+		new_fl |= S_ENCRYPTED;
+	if (flags & EXT4_CASEFOLD_FL)
+		new_fl |= S_CASEFOLD;
+	if (flags & EXT4_VERITY_FL)
+		new_fl |= S_VERITY;
+	inode_set_flags(inode, new_fl,
+			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
+			S_ENCRYPTED|S_CASEFOLD|S_VERITY);
+}
+
+static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
+				  struct ext4_inode_info *ei)
+{
+	blkcnt_t i_blocks ;
+	struct inode *inode = &(ei->vfs_inode);
+	struct super_block *sb = inode->i_sb;
+
+	if (ext4_has_feature_huge_file(sb)) {
+		/* we are using combined 48 bit field */
+		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
+					le32_to_cpu(raw_inode->i_blocks_lo);
+		if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
+			/* i_blocks represent file system block size */
+			return i_blocks  << (inode->i_blkbits - 9);
+		} else {
+			return i_blocks;
+		}
+	} else {
+		return le32_to_cpu(raw_inode->i_blocks_lo);
+	}
+}
+
+static inline int ext4_iget_extra_inode(struct inode *inode,
+					 struct ext4_inode *raw_inode,
+					 struct ext4_inode_info *ei)
+{
+	__le32 *magic = (void *)raw_inode +
+			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
+
+	if (EXT4_INODE_HAS_XATTR_SPACE(inode)  &&
+	    *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
+		int err;
+
+		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
+		err = ext4_find_inline_data_nolock(inode);
+		if (!err && ext4_has_inline_data(inode))
+			ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
+		return err;
+	} else
+		EXT4_I(inode)->i_inline_off = 0;
+	return 0;
+}
+
+int ext4_get_projid(struct inode *inode, kprojid_t *projid)
+{
+	if (!ext4_has_feature_project(inode->i_sb))
+		return -EOPNOTSUPP;
+	*projid = EXT4_I(inode)->i_projid;
+	return 0;
+}
+
+/*
+ * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
+ * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
+ * set.
+ */
+static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
+{
+	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
+		inode_set_iversion_raw(inode, val);
+	else
+		inode_set_iversion_queried(inode, val);
+}
+static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
+{
+	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
+		return inode_peek_iversion_raw(inode);
+	else
+		return inode_peek_iversion(inode);
+}
+
+static const char *check_igot_inode(struct inode *inode, ext4_iget_flags flags)
+
+{
+	if (flags & EXT4_IGET_EA_INODE) {
+		if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
+			return "missing EA_INODE flag";
+		if (ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
+		    EXT4_I(inode)->i_file_acl)
+			return "ea_inode with extended attributes";
+	} else {
+		if ((EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
+			return "unexpected EA_INODE flag";
+	}
+	if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD))
+		return "unexpected bad inode w/o EXT4_IGET_BAD";
+	return NULL;
+}
+
+struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
+			  ext4_iget_flags flags, const char *function,
+			  unsigned int line)
+{
+	struct ext4_iloc iloc;
+	struct ext4_inode *raw_inode;
+	struct ext4_inode_info *ei;
+	struct inode *inode;
+	const char *err_str;
+	journal_t *journal = EXT4_SB(sb)->s_journal;
+	long ret;
+	loff_t size;
+	int block;
+	uid_t i_uid;
+	gid_t i_gid;
+	projid_t i_projid;
+
+	if ((!(flags & EXT4_IGET_SPECIAL) &&
+	     (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)) ||
+	    (ino < EXT4_ROOT_INO) ||
+	    (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))) {
+		if (flags & EXT4_IGET_HANDLE)
+			return ERR_PTR(-ESTALE);
+		__ext4_error(sb, function, line, EFSCORRUPTED, 0,
+			     "inode #%lu: comm %s: iget: illegal inode #",
+			     ino, current->comm);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW)) {
+		if ((err_str = check_igot_inode(inode, flags)) != NULL) {
+			ext4_error_inode(inode, function, line, 0, err_str);
+			iput(inode);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+		return inode;
+	}
+
+	ei = EXT4_I(inode);
+	iloc.bh = NULL;
+
+	ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
+	if (ret < 0)
+		goto bad_inode;
+	raw_inode = ext4_raw_inode(&iloc);
+
+	if ((flags & EXT4_IGET_HANDLE) &&
+	    (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
+		ret = -ESTALE;
+		goto bad_inode;
+	}
+
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
+		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
+			EXT4_INODE_SIZE(inode->i_sb) ||
+		    (ei->i_extra_isize & 3)) {
+			ext4_error_inode(inode, function, line, 0,
+					 "iget: bad extra_isize %u "
+					 "(inode size %u)",
+					 ei->i_extra_isize,
+					 EXT4_INODE_SIZE(inode->i_sb));
+			ret = -EFSCORRUPTED;
+			goto bad_inode;
+		}
+	} else
+		ei->i_extra_isize = 0;
+
+	/* Precompute checksum seed for inode metadata */
+	if (ext4_has_metadata_csum(sb)) {
+		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+		__u32 csum;
+		__le32 inum = cpu_to_le32(inode->i_ino);
+		__le32 gen = raw_inode->i_generation;
+		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
+				   sizeof(inum));
+		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
+					      sizeof(gen));
+	}
+
+	if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
+	    ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
+	     (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
+		ext4_error_inode_err(inode, function, line, 0,
+				EFSBADCRC, "iget: checksum invalid");
+		ret = -EFSBADCRC;
+		goto bad_inode;
+	}
+
+	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
+	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
+	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
+	if (ext4_has_feature_project(sb) &&
+	    EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
+	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
+		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
+	else
+		i_projid = EXT4_DEF_PROJID;
+
+	if (!(test_opt(inode->i_sb, NO_UID32))) {
+		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
+		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
+	}
+	i_uid_write(inode, i_uid);
+	i_gid_write(inode, i_gid);
+	ei->i_projid = make_kprojid(&init_user_ns, i_projid);
+	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
+
+	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
+	ei->i_inline_off = 0;
+	ei->i_dir_start_lookup = 0;
+	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
+	/* We now have enough fields to check if the inode was active or not.
+	 * This is needed because nfsd might try to access dead inodes
+	 * the test is that same one that e2fsck uses
+	 * NeilBrown 1999oct15
+	 */
+	if (inode->i_nlink == 0) {
+		if ((inode->i_mode == 0 || flags & EXT4_IGET_SPECIAL ||
+		     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
+		    ino != EXT4_BOOT_LOADER_INO) {
+			/* this inode is deleted or unallocated */
+			if (flags & EXT4_IGET_SPECIAL) {
+				ext4_error_inode(inode, function, line, 0,
+						 "iget: special inode unallocated");
+				ret = -EFSCORRUPTED;
+			} else
+				ret = -ESTALE;
+			goto bad_inode;
+		}
+		/* The only unlinked inodes we let through here have
+		 * valid i_mode and are being read by the orphan
+		 * recovery code: that's fine, we're about to complete
+		 * the process of deleting those.
+		 * OR it is the EXT4_BOOT_LOADER_INO which is
+		 * not initialized on a new filesystem. */
+	}
+	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
+	ext4_set_inode_flags(inode, true);
+	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
+	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
+	if (ext4_has_feature_64bit(sb))
+		ei->i_file_acl |=
+			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
+	inode->i_size = ext4_isize(sb, raw_inode);
+	if ((size = i_size_read(inode)) < 0) {
+		ext4_error_inode(inode, function, line, 0,
+				 "iget: bad i_size value: %lld", size);
+		ret = -EFSCORRUPTED;
+		goto bad_inode;
+	}
+	/*
+	 * If dir_index is not enabled but there's dir with INDEX flag set,
+	 * we'd normally treat htree data as empty space. But with metadata
+	 * checksumming that corrupts checksums so forbid that.
+	 */
+	if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
+	    ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
+		ext4_error_inode(inode, function, line, 0,
+			 "iget: Dir with htree data on filesystem without dir_index feature.");
+		ret = -EFSCORRUPTED;
+		goto bad_inode;
+	}
+	ei->i_disksize = inode->i_size;
+#ifdef CONFIG_QUOTA
+	ei->i_reserved_quota = 0;
+#endif
+	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
+	ei->i_block_group = iloc.block_group;
+	ei->i_last_alloc_group = ~0;
+	/*
+	 * NOTE! The in-memory inode i_data array is in little-endian order
+	 * even on big-endian machines: we do NOT byteswap the block numbers!
+	 */
+	for (block = 0; block < EXT4_N_BLOCKS; block++)
+		ei->i_data[block] = raw_inode->i_block[block];
+	INIT_LIST_HEAD(&ei->i_orphan);
+	ext4_fc_init_inode(&ei->vfs_inode);
+
+	/*
+	 * Set transaction id's of transactions that have to be committed
+	 * to finish f[data]sync. We set them to currently running transaction
+	 * as we cannot be sure that the inode or some of its metadata isn't
+	 * part of the transaction - the inode could have been reclaimed and
+	 * now it is reread from disk.
+	 */
+	if (journal) {
+		transaction_t *transaction;
+		tid_t tid;
+
+		read_lock(&journal->j_state_lock);
+		if (journal->j_running_transaction)
+			transaction = journal->j_running_transaction;
+		else
+			transaction = journal->j_committing_transaction;
+		if (transaction)
+			tid = transaction->t_tid;
+		else
+			tid = journal->j_commit_sequence;
+		read_unlock(&journal->j_state_lock);
+		ei->i_sync_tid = tid;
+		ei->i_datasync_tid = tid;
+	}
+
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+		if (ei->i_extra_isize == 0) {
+			/* The extra space is currently unused. Use it. */
+			BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
+			ei->i_extra_isize = sizeof(struct ext4_inode) -
+					    EXT4_GOOD_OLD_INODE_SIZE;
+		} else {
+			ret = ext4_iget_extra_inode(inode, raw_inode, ei);
+			if (ret)
+				goto bad_inode;
+		}
+	}
+
+	EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
+	EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
+	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
+	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
+
+	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
+		u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
+
+		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+				ivers |=
+		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
+		}
+		ext4_inode_set_iversion_queried(inode, ivers);
+	}
+
+	ret = 0;
+	if (ei->i_file_acl &&
+	    !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
+		ext4_error_inode(inode, function, line, 0,
+				 "iget: bad extended attribute block %llu",
+				 ei->i_file_acl);
+		ret = -EFSCORRUPTED;
+		goto bad_inode;
+	} else if (!ext4_has_inline_data(inode)) {
+		/* validate the block references in the inode */
+		if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
+			(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+			(S_ISLNK(inode->i_mode) &&
+			!ext4_inode_is_fast_symlink(inode)))) {
+			if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+				ret = ext4_ext_check_inode(inode);
+			else
+				ret = ext4_ind_check_inode(inode);
+		}
+	}
+	if (ret)
+		goto bad_inode;
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = &ext4_file_inode_operations;
+		inode->i_fop = &ext4_file_operations;
+		ext4_set_aops(inode);
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = &ext4_dir_inode_operations;
+		inode->i_fop = &ext4_dir_operations;
+	} else if (S_ISLNK(inode->i_mode)) {
+		/* VFS does not allow setting these so must be corruption */
+		if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
+			ext4_error_inode(inode, function, line, 0,
+					 "iget: immutable or append flags "
+					 "not allowed on symlinks");
+			ret = -EFSCORRUPTED;
+			goto bad_inode;
+		}
+		if (IS_ENCRYPTED(inode)) {
+			inode->i_op = &ext4_encrypted_symlink_inode_operations;
+			ext4_set_aops(inode);
+		} else if (ext4_inode_is_fast_symlink(inode)) {
+			inode->i_link = (char *)ei->i_data;
+			inode->i_op = &ext4_fast_symlink_inode_operations;
+			nd_terminate_link(ei->i_data, inode->i_size,
+				sizeof(ei->i_data) - 1);
+		} else {
+			inode->i_op = &ext4_symlink_inode_operations;
+			ext4_set_aops(inode);
+		}
+		inode_nohighmem(inode);
+	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
+		inode->i_op = &ext4_special_inode_operations;
+		if (raw_inode->i_block[0])
+			init_special_inode(inode, inode->i_mode,
+			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
+		else
+			init_special_inode(inode, inode->i_mode,
+			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
+	} else if (ino == EXT4_BOOT_LOADER_INO) {
+		make_bad_inode(inode);
+	} else {
+		ret = -EFSCORRUPTED;
+		ext4_error_inode(inode, function, line, 0,
+				 "iget: bogus i_mode (%o)", inode->i_mode);
+		goto bad_inode;
+	}
+	if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb))
+		ext4_error_inode(inode, function, line, 0,
+				 "casefold flag without casefold feature");
+	if ((err_str = check_igot_inode(inode, flags)) != NULL) {
+		ext4_error_inode(inode, function, line, 0, err_str);
+		ret = -EFSCORRUPTED;
+		goto bad_inode;
+	}
+
+	brelse(iloc.bh);
+	unlock_new_inode(inode);
+	return inode;
+
+bad_inode:
+	brelse(iloc.bh);
+	iget_failed(inode);
+	return ERR_PTR(ret);
+}
+
+static int ext4_inode_blocks_set(handle_t *handle,
+				struct ext4_inode *raw_inode,
+				struct ext4_inode_info *ei)
+{
+	struct inode *inode = &(ei->vfs_inode);
+	u64 i_blocks = READ_ONCE(inode->i_blocks);
+	struct super_block *sb = inode->i_sb;
+
+	if (i_blocks <= ~0U) {
+		/*
+		 * i_blocks can be represented in a 32 bit variable
+		 * as multiple of 512 bytes
+		 */
+		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
+		raw_inode->i_blocks_high = 0;
+		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
+		return 0;
+	}
+	if (!ext4_has_feature_huge_file(sb))
+		return -EFBIG;
+
+	if (i_blocks <= 0xffffffffffffULL) {
+		/*
+		 * i_blocks can be represented in a 48 bit variable
+		 * as multiple of 512 bytes
+		 */
+		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
+		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
+		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
+	} else {
+		ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
+		/* i_block is stored in file system block size */
+		i_blocks = i_blocks >> (inode->i_blkbits - 9);
+		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
+		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
+	}
+	return 0;
+}
+
+static void __ext4_update_other_inode_time(struct super_block *sb,
+					   unsigned long orig_ino,
+					   unsigned long ino,
+					   struct ext4_inode *raw_inode)
+{
+	struct inode *inode;
+
+	inode = find_inode_by_ino_rcu(sb, ino);
+	if (!inode)
+		return;
+
+	if ((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
+			       I_DIRTY_INODE)) ||
+	    ((inode->i_state & I_DIRTY_TIME) == 0))
+		return;
+
+	spin_lock(&inode->i_lock);
+	if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
+				I_DIRTY_INODE)) == 0) &&
+	    (inode->i_state & I_DIRTY_TIME)) {
+		struct ext4_inode_info	*ei = EXT4_I(inode);
+
+		inode->i_state &= ~I_DIRTY_TIME;
+		spin_unlock(&inode->i_lock);
+
+		spin_lock(&ei->i_raw_lock);
+		EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
+		EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
+		EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
+		ext4_inode_csum_set(inode, raw_inode, ei);
+		spin_unlock(&ei->i_raw_lock);
+		trace_ext4_other_inode_update_time(inode, orig_ino);
+		return;
+	}
+	spin_unlock(&inode->i_lock);
+}
+
+/*
+ * Opportunistically update the other time fields for other inodes in
+ * the same inode table block.
+ */
+static void ext4_update_other_inodes_time(struct super_block *sb,
+					  unsigned long orig_ino, char *buf)
+{
+	unsigned long ino;
+	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
+	int inode_size = EXT4_INODE_SIZE(sb);
+
+	/*
+	 * Calculate the first inode in the inode table block.  Inode
+	 * numbers are one-based.  That is, the first inode in a block
+	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
+	 */
+	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
+	rcu_read_lock();
+	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
+		if (ino == orig_ino)
+			continue;
+		__ext4_update_other_inode_time(sb, orig_ino, ino,
+					       (struct ext4_inode *)buf);
+	}
+	rcu_read_unlock();
+}
+
+/*
+ * Post the struct inode info into an on-disk inode location in the
+ * buffer-cache.  This gobbles the caller's reference to the
+ * buffer_head in the inode location struct.
+ *
+ * The caller must have write access to iloc->bh.
+ */
+static int ext4_do_update_inode(handle_t *handle,
+				struct inode *inode,
+				struct ext4_iloc *iloc)
+{
+	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct buffer_head *bh = iloc->bh;
+	struct super_block *sb = inode->i_sb;
+	int err = 0, block;
+	int need_datasync = 0, set_large_file = 0;
+	uid_t i_uid;
+	gid_t i_gid;
+	projid_t i_projid;
+
+	spin_lock(&ei->i_raw_lock);
+
+	/* For fields not tracked in the in-memory inode,
+	 * initialise them to zero for new inodes. */
+	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
+		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
+
+	err = ext4_inode_blocks_set(handle, raw_inode, ei);
+	if (err) {
+		spin_unlock(&ei->i_raw_lock);
+		goto out_brelse;
+	}
+
+	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
+	i_uid = i_uid_read(inode);
+	i_gid = i_gid_read(inode);
+	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
+	if (!(test_opt(inode->i_sb, NO_UID32))) {
+		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
+		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
+/*
+ * Fix up interoperability with old kernels. Otherwise, old inodes get
+ * re-used with the upper 16 bits of the uid/gid intact
+ */
+		if (ei->i_dtime && list_empty(&ei->i_orphan)) {
+			raw_inode->i_uid_high = 0;
+			raw_inode->i_gid_high = 0;
+		} else {
+			raw_inode->i_uid_high =
+				cpu_to_le16(high_16_bits(i_uid));
+			raw_inode->i_gid_high =
+				cpu_to_le16(high_16_bits(i_gid));
+		}
+	} else {
+		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
+		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
+		raw_inode->i_uid_high = 0;
+		raw_inode->i_gid_high = 0;
+	}
+	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
+
+	EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
+	EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
+	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
+	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
+
+	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
+	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
+	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
+		raw_inode->i_file_acl_high =
+			cpu_to_le16(ei->i_file_acl >> 32);
+	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
+	if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode)) {
+		ext4_isize_set(raw_inode, ei->i_disksize);
+		need_datasync = 1;
+	}
+	if (ei->i_disksize > 0x7fffffffULL) {
+		if (!ext4_has_feature_large_file(sb) ||
+				EXT4_SB(sb)->s_es->s_rev_level ==
+		    cpu_to_le32(EXT4_GOOD_OLD_REV))
+			set_large_file = 1;
+	}
+	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
+	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+		if (old_valid_dev(inode->i_rdev)) {
+			raw_inode->i_block[0] =
+				cpu_to_le32(old_encode_dev(inode->i_rdev));
+			raw_inode->i_block[1] = 0;
+		} else {
+			raw_inode->i_block[0] = 0;
+			raw_inode->i_block[1] =
+				cpu_to_le32(new_encode_dev(inode->i_rdev));
+			raw_inode->i_block[2] = 0;
+		}
+	} else if (!ext4_has_inline_data(inode)) {
+		for (block = 0; block < EXT4_N_BLOCKS; block++)
+			raw_inode->i_block[block] = ei->i_data[block];
+	}
+
+	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
+		u64 ivers = ext4_inode_peek_iversion(inode);
+
+		raw_inode->i_disk_version = cpu_to_le32(ivers);
+		if (ei->i_extra_isize) {
+			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+				raw_inode->i_version_hi =
+					cpu_to_le32(ivers >> 32);
+			raw_inode->i_extra_isize =
+				cpu_to_le16(ei->i_extra_isize);
+		}
+	}
+
+	BUG_ON(!ext4_has_feature_project(inode->i_sb) &&
+	       i_projid != EXT4_DEF_PROJID);
+
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
+	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
+		raw_inode->i_projid = cpu_to_le32(i_projid);
+
+	ext4_inode_csum_set(inode, raw_inode, ei);
+	spin_unlock(&ei->i_raw_lock);
+	if (inode->i_sb->s_flags & SB_LAZYTIME)
+		ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
+					      bh->b_data);
+
+	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_metadata(handle, NULL, bh);
+	if (err)
+		goto out_brelse;
+	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
+	if (set_large_file) {
+		BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
+		err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
+		if (err)
+			goto out_brelse;
+		ext4_set_feature_large_file(sb);
+		ext4_handle_sync(handle);
+		err = ext4_handle_dirty_super(handle, sb);
+	}
+	ext4_update_inode_fsync_trans(handle, inode, need_datasync);
+out_brelse:
+	brelse(bh);
+	ext4_std_error(inode->i_sb, err);
+	return err;
+}
+
+/*
+ * ext4_write_inode()
+ *
+ * We are called from a few places:
+ *
+ * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
+ *   Here, there will be no transaction running. We wait for any running
+ *   transaction to commit.
+ *
+ * - Within flush work (sys_sync(), kupdate and such).
+ *   We wait on commit, if told to.
+ *
+ * - Within iput_final() -> write_inode_now()
+ *   We wait on commit, if told to.
+ *
+ * In all cases it is actually safe for us to return without doing anything,
+ * because the inode has been copied into a raw inode buffer in
+ * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
+ * writeback.
+ *
+ * Note that we are absolutely dependent upon all inode dirtiers doing the
+ * right thing: they *must* call mark_inode_dirty() after dirtying info in
+ * which we are interested.
+ *
+ * It would be a bug for them to not do this.  The code:
+ *
+ *	mark_inode_dirty(inode)
+ *	stuff();
+ *	inode->i_size = expr;
+ *
+ * is in error because write_inode() could occur while `stuff()' is running,
+ * and the new i_size will be lost.  Plus the inode will no longer be on the
+ * superblock's dirty inode list.
+ */
+int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	int err;
+
+	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC) ||
+	    sb_rdonly(inode->i_sb))
+		return 0;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	if (EXT4_SB(inode->i_sb)->s_journal) {
+		if (ext4_journal_current_handle()) {
+			jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
+			dump_stack();
+			return -EIO;
+		}
+
+		/*
+		 * No need to force transaction in WB_SYNC_NONE mode. Also
+		 * ext4_sync_fs() will force the commit after everything is
+		 * written.
+		 */
+		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
+			return 0;
+
+		err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
+						EXT4_I(inode)->i_sync_tid);
+	} else {
+		struct ext4_iloc iloc;
+
+		err = __ext4_get_inode_loc_noinmem(inode, &iloc);
+		if (err)
+			return err;
+		/*
+		 * sync(2) will flush the whole buffer cache. No need to do
+		 * it here separately for each inode.
+		 */
+		if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
+			sync_dirty_buffer(iloc.bh);
+		if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
+			ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
+					       "IO error syncing inode");
+			err = -EIO;
+		}
+		brelse(iloc.bh);
+	}
+	return err;
+}
+
+/*
+ * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
+ * buffers that are attached to a page stradding i_size and are undergoing
+ * commit. In that case we have to wait for commit to finish and try again.
+ */
+static void ext4_wait_for_tail_page_commit(struct inode *inode)
+{
+	struct page *page;
+	unsigned offset;
+	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+	tid_t commit_tid = 0;
+	int ret;
+
+	offset = inode->i_size & (PAGE_SIZE - 1);
+	/*
+	 * If the page is fully truncated, we don't need to wait for any commit
+	 * (and we even should not as __ext4_journalled_invalidatepage() may
+	 * strip all buffers from the page but keep the page dirty which can then
+	 * confuse e.g. concurrent ext4_writepage() seeing dirty page without
+	 * buffers). Also we don't need to wait for any commit if all buffers in
+	 * the page remain valid. This is most beneficial for the common case of
+	 * blocksize == PAGESIZE.
+	 */
+	if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
+		return;
+	while (1) {
+		page = find_lock_page(inode->i_mapping,
+				      inode->i_size >> PAGE_SHIFT);
+		if (!page)
+			return;
+		ret = __ext4_journalled_invalidatepage(page, offset,
+						PAGE_SIZE - offset);
+		unlock_page(page);
+		put_page(page);
+		if (ret != -EBUSY)
+			return;
+		commit_tid = 0;
+		read_lock(&journal->j_state_lock);
+		if (journal->j_committing_transaction)
+			commit_tid = journal->j_committing_transaction->t_tid;
+		read_unlock(&journal->j_state_lock);
+		if (commit_tid)
+			jbd2_log_wait_commit(journal, commit_tid);
+	}
+}
+
+/*
+ * ext4_setattr()
+ *
+ * Called from notify_change.
+ *
+ * We want to trap VFS attempts to truncate the file as soon as
+ * possible.  In particular, we want to make sure that when the VFS
+ * shrinks i_size, we put the inode on the orphan list and modify
+ * i_disksize immediately, so that during the subsequent flushing of
+ * dirty pages and freeing of disk blocks, we can guarantee that any
+ * commit will leave the blocks being flushed in an unused state on
+ * disk.  (On recovery, the inode will get truncated and the blocks will
+ * be freed, so we have a strong guarantee that no future commit will
+ * leave these blocks visible to the user.)
+ *
+ * Another thing we have to assure is that if we are in ordered mode
+ * and inode is still attached to the committing transaction, we must
+ * we start writeout of all the dirty pages which are being truncated.
+ * This way we are sure that all the data written in the previous
+ * transaction are already on disk (truncate waits for pages under
+ * writeback).
+ *
+ * Called with inode->i_mutex down.
+ */
+int ext4_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = d_inode(dentry);
+	int error, rc = 0;
+	int orphan = 0;
+	const unsigned int ia_valid = attr->ia_valid;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	if (unlikely(IS_IMMUTABLE(inode)))
+		return -EPERM;
+
+	if (unlikely(IS_APPEND(inode) &&
+		     (ia_valid & (ATTR_MODE | ATTR_UID |
+				  ATTR_GID | ATTR_TIMES_SET))))
+		return -EPERM;
+
+	error = setattr_prepare(dentry, attr);
+	if (error)
+		return error;
+
+	error = fscrypt_prepare_setattr(dentry, attr);
+	if (error)
+		return error;
+
+	error = fsverity_prepare_setattr(dentry, attr);
+	if (error)
+		return error;
+
+	if (is_quota_modification(inode, attr)) {
+		error = dquot_initialize(inode);
+		if (error)
+			return error;
+	}
+
+	if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
+	    (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
+		handle_t *handle;
+
+		/* (user+group)*(old+new) structure, inode write (sb,
+		 * inode block, ? - but truncate inode update has it) */
+		handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
+			(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
+			 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
+		if (IS_ERR(handle)) {
+			error = PTR_ERR(handle);
+			goto err_out;
+		}
+
+		/* dquot_transfer() calls back ext4_get_inode_usage() which
+		 * counts xattr inode references.
+		 */
+		down_read(&EXT4_I(inode)->xattr_sem);
+		error = dquot_transfer(inode, attr);
+		up_read(&EXT4_I(inode)->xattr_sem);
+
+		if (error) {
+			ext4_journal_stop(handle);
+			return error;
+		}
+		/* Update corresponding info in inode so that everything is in
+		 * one transaction */
+		if (attr->ia_valid & ATTR_UID)
+			inode->i_uid = attr->ia_uid;
+		if (attr->ia_valid & ATTR_GID)
+			inode->i_gid = attr->ia_gid;
+		error = ext4_mark_inode_dirty(handle, inode);
+		ext4_journal_stop(handle);
+		if (unlikely(error)) {
+			return error;
+		}
+	}
+
+	if (attr->ia_valid & ATTR_SIZE) {
+		handle_t *handle;
+		loff_t oldsize = inode->i_size;
+		loff_t old_disksize;
+		int shrink = (attr->ia_size < inode->i_size);
+
+		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+			if (attr->ia_size > sbi->s_bitmap_maxbytes) {
+				return -EFBIG;
+			}
+		}
+		if (!S_ISREG(inode->i_mode)) {
+			return -EINVAL;
+		}
+
+		if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
+			inode_inc_iversion(inode);
+
+		if (shrink) {
+			if (ext4_should_order_data(inode)) {
+				error = ext4_begin_ordered_truncate(inode,
+							    attr->ia_size);
+				if (error)
+					goto err_out;
+			}
+			/*
+			 * Blocks are going to be removed from the inode. Wait
+			 * for dio in flight.
+			 */
+			inode_dio_wait(inode);
+		}
+
+		down_write(&EXT4_I(inode)->i_mmap_sem);
+
+		rc = ext4_break_layouts(inode);
+		if (rc) {
+			up_write(&EXT4_I(inode)->i_mmap_sem);
+			goto err_out;
+		}
+
+		if (attr->ia_size != inode->i_size) {
+			handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
+			if (IS_ERR(handle)) {
+				error = PTR_ERR(handle);
+				goto out_mmap_sem;
+			}
+			if (ext4_handle_valid(handle) && shrink) {
+				error = ext4_orphan_add(handle, inode);
+				orphan = 1;
+			}
+			/*
+			 * Update c/mtime on truncate up, ext4_truncate() will
+			 * update c/mtime in shrink case below
+			 */
+			if (!shrink) {
+				inode->i_mtime = current_time(inode);
+				inode->i_ctime = inode->i_mtime;
+			}
+
+			if (shrink)
+				ext4_fc_track_range(handle, inode,
+					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
+					inode->i_sb->s_blocksize_bits,
+					EXT_MAX_BLOCKS - 1);
+			else
+				ext4_fc_track_range(
+					handle, inode,
+					(oldsize > 0 ? oldsize - 1 : oldsize) >>
+					inode->i_sb->s_blocksize_bits,
+					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
+					inode->i_sb->s_blocksize_bits);
+
+			down_write(&EXT4_I(inode)->i_data_sem);
+			old_disksize = EXT4_I(inode)->i_disksize;
+			EXT4_I(inode)->i_disksize = attr->ia_size;
+			rc = ext4_mark_inode_dirty(handle, inode);
+			if (!error)
+				error = rc;
+			/*
+			 * We have to update i_size under i_data_sem together
+			 * with i_disksize to avoid races with writeback code
+			 * running ext4_wb_update_i_disksize().
+			 */
+			if (!error)
+				i_size_write(inode, attr->ia_size);
+			else
+				EXT4_I(inode)->i_disksize = old_disksize;
+			up_write(&EXT4_I(inode)->i_data_sem);
+			ext4_journal_stop(handle);
+			if (error)
+				goto out_mmap_sem;
+			if (!shrink) {
+				pagecache_isize_extended(inode, oldsize,
+							 inode->i_size);
+			} else if (ext4_should_journal_data(inode)) {
+				ext4_wait_for_tail_page_commit(inode);
+			}
+		}
+
+		/*
+		 * Truncate pagecache after we've waited for commit
+		 * in data=journal mode to make pages freeable.
+		 */
+		truncate_pagecache(inode, inode->i_size);
+		/*
+		 * Call ext4_truncate() even if i_size didn't change to
+		 * truncate possible preallocated blocks.
+		 */
+		if (attr->ia_size <= oldsize) {
+			rc = ext4_truncate(inode);
+			if (rc)
+				error = rc;
+		}
+out_mmap_sem:
+		up_write(&EXT4_I(inode)->i_mmap_sem);
+	}
+
+	if (!error) {
+		setattr_copy(inode, attr);
+		mark_inode_dirty(inode);
+	}
+
+	/*
+	 * If the call to ext4_truncate failed to get a transaction handle at
+	 * all, we need to clean up the in-core orphan list manually.
+	 */
+	if (orphan && inode->i_nlink)
+		ext4_orphan_del(NULL, inode);
+
+	if (!error && (ia_valid & ATTR_MODE))
+		rc = posix_acl_chmod(inode, inode->i_mode);
+
+err_out:
+	if  (error)
+		ext4_std_error(inode->i_sb, error);
+	if (!error)
+		error = rc;
+	return error;
+}
+
+int ext4_getattr(const struct path *path, struct kstat *stat,
+		 u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct ext4_inode *raw_inode;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	unsigned int flags;
+
+	if ((request_mask & STATX_BTIME) &&
+	    EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
+		stat->result_mask |= STATX_BTIME;
+		stat->btime.tv_sec = ei->i_crtime.tv_sec;
+		stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
+	}
+
+	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
+	if (flags & EXT4_APPEND_FL)
+		stat->attributes |= STATX_ATTR_APPEND;
+	if (flags & EXT4_COMPR_FL)
+		stat->attributes |= STATX_ATTR_COMPRESSED;
+	if (flags & EXT4_ENCRYPT_FL)
+		stat->attributes |= STATX_ATTR_ENCRYPTED;
+	if (flags & EXT4_IMMUTABLE_FL)
+		stat->attributes |= STATX_ATTR_IMMUTABLE;
+	if (flags & EXT4_NODUMP_FL)
+		stat->attributes |= STATX_ATTR_NODUMP;
+	if (flags & EXT4_VERITY_FL)
+		stat->attributes |= STATX_ATTR_VERITY;
+
+	stat->attributes_mask |= (STATX_ATTR_APPEND |
+				  STATX_ATTR_COMPRESSED |
+				  STATX_ATTR_ENCRYPTED |
+				  STATX_ATTR_IMMUTABLE |
+				  STATX_ATTR_NODUMP |
+				  STATX_ATTR_VERITY);
+
+	generic_fillattr(inode, stat);
+	return 0;
+}
+
+int ext4_file_getattr(const struct path *path, struct kstat *stat,
+		      u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	u64 delalloc_blocks;
+
+	ext4_getattr(path, stat, request_mask, query_flags);
+
+	/*
+	 * If there is inline data in the inode, the inode will normally not
+	 * have data blocks allocated (it may have an external xattr block).
+	 * Report at least one sector for such files, so tools like tar, rsync,
+	 * others don't incorrectly think the file is completely sparse.
+	 */
+	if (unlikely(ext4_has_inline_data(inode)))
+		stat->blocks += (stat->size + 511) >> 9;
+
+	/*
+	 * We can't update i_blocks if the block allocation is delayed
+	 * otherwise in the case of system crash before the real block
+	 * allocation is done, we will have i_blocks inconsistent with
+	 * on-disk file blocks.
+	 * We always keep i_blocks updated together with real
+	 * allocation. But to not confuse with user, stat
+	 * will return the blocks that include the delayed allocation
+	 * blocks for this file.
+	 */
+	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
+				   EXT4_I(inode)->i_reserved_data_blocks);
+	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
+	return 0;
+}
+
+static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
+				   int pextents)
+{
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		return ext4_ind_trans_blocks(inode, lblocks);
+	return ext4_ext_index_trans_blocks(inode, pextents);
+}
+
+/*
+ * Account for index blocks, block groups bitmaps and block group
+ * descriptor blocks if modify datablocks and index blocks
+ * worse case, the indexs blocks spread over different block groups
+ *
+ * If datablocks are discontiguous, they are possible to spread over
+ * different block groups too. If they are contiguous, with flexbg,
+ * they could still across block group boundary.
+ *
+ * Also account for superblock, inode, quota and xattr blocks
+ */
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+				  int pextents)
+{
+	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
+	int gdpblocks;
+	int idxblocks;
+	int ret = 0;
+
+	/*
+	 * How many index blocks need to touch to map @lblocks logical blocks
+	 * to @pextents physical extents?
+	 */
+	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
+
+	ret = idxblocks;
+
+	/*
+	 * Now let's see how many group bitmaps and group descriptors need
+	 * to account
+	 */
+	groups = idxblocks + pextents;
+	gdpblocks = groups;
+	if (groups > ngroups)
+		groups = ngroups;
+	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
+		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
+
+	/* bitmaps and block group descriptor blocks */
+	ret += groups + gdpblocks;
+
+	/* Blocks for super block, inode, quota and xattr blocks */
+	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
+
+	return ret;
+}
+
+/*
+ * Calculate the total number of credits to reserve to fit
+ * the modification of a single pages into a single transaction,
+ * which may include multiple chunks of block allocations.
+ *
+ * This could be called via ext4_write_begin()
+ *
+ * We need to consider the worse case, when
+ * one new block per extent.
+ */
+int ext4_writepage_trans_blocks(struct inode *inode)
+{
+	int bpp = ext4_journal_blocks_per_page(inode);
+	int ret;
+
+	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
+
+	/* Account for data blocks for journalled mode */
+	if (ext4_should_journal_data(inode))
+		ret += bpp;
+	return ret;
+}
+
+/*
+ * Calculate the journal credits for a chunk of data modification.
+ *
+ * This is called from DIO, fallocate or whoever calling
+ * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
+ *
+ * journal buffers for data blocks are not included here, as DIO
+ * and fallocate do no need to journal data buffers.
+ */
+int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
+{
+	return ext4_meta_trans_blocks(inode, nrblocks, 1);
+}
+
+/*
+ * The caller must have previously called ext4_reserve_inode_write().
+ * Give this, we know that the caller already has write access to iloc->bh.
+ */
+int ext4_mark_iloc_dirty(handle_t *handle,
+			 struct inode *inode, struct ext4_iloc *iloc)
+{
+	int err = 0;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
+		put_bh(iloc->bh);
+		return -EIO;
+	}
+	ext4_fc_track_inode(handle, inode);
+
+	/*
+	 * ea_inodes are using i_version for storing reference count, don't
+	 * mess with it
+	 */
+	if (IS_I_VERSION(inode) &&
+	    !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
+		inode_inc_iversion(inode);
+
+	/* the do_update_inode consumes one bh->b_count */
+	get_bh(iloc->bh);
+
+	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
+	err = ext4_do_update_inode(handle, inode, iloc);
+	put_bh(iloc->bh);
+	return err;
+}
+
+/*
+ * On success, We end up with an outstanding reference count against
+ * iloc->bh.  This _must_ be cleaned up later.
+ */
+
+int
+ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
+			 struct ext4_iloc *iloc)
+{
+	int err;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	err = ext4_get_inode_loc(inode, iloc);
+	if (!err) {
+		BUFFER_TRACE(iloc->bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, iloc->bh);
+		if (err) {
+			brelse(iloc->bh);
+			iloc->bh = NULL;
+		}
+	}
+	ext4_std_error(inode->i_sb, err);
+	return err;
+}
+
+static int __ext4_expand_extra_isize(struct inode *inode,
+				     unsigned int new_extra_isize,
+				     struct ext4_iloc *iloc,
+				     handle_t *handle, int *no_expand)
+{
+	struct ext4_inode *raw_inode;
+	struct ext4_xattr_ibody_header *header;
+	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	int error;
+
+	/* this was checked at iget time, but double check for good measure */
+	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
+	    (ei->i_extra_isize & 3)) {
+		EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
+				 ei->i_extra_isize,
+				 EXT4_INODE_SIZE(inode->i_sb));
+		return -EFSCORRUPTED;
+	}
+	if ((new_extra_isize < ei->i_extra_isize) ||
+	    (new_extra_isize < 4) ||
+	    (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
+		return -EINVAL;	/* Should never happen */
+
+	raw_inode = ext4_raw_inode(iloc);
+
+	header = IHDR(inode, raw_inode);
+
+	/* No extended attributes present */
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
+	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
+		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
+		       EXT4_I(inode)->i_extra_isize, 0,
+		       new_extra_isize - EXT4_I(inode)->i_extra_isize);
+		EXT4_I(inode)->i_extra_isize = new_extra_isize;
+		return 0;
+	}
+
+	/*
+	 * We may need to allocate external xattr block so we need quotas
+	 * initialized. Here we can be called with various locks held so we
+	 * cannot affort to initialize quotas ourselves. So just bail.
+	 */
+	if (dquot_initialize_needed(inode))
+		return -EAGAIN;
+
+	/* try to expand with EAs present */
+	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
+					   raw_inode, handle);
+	if (error) {
+		/*
+		 * Inode size expansion failed; don't try again
+		 */
+		*no_expand = 1;
+	}
+
+	return error;
+}
+
+/*
+ * Expand an inode by new_extra_isize bytes.
+ * Returns 0 on success or negative error number on failure.
+ */
+static int ext4_try_to_expand_extra_isize(struct inode *inode,
+					  unsigned int new_extra_isize,
+					  struct ext4_iloc iloc,
+					  handle_t *handle)
+{
+	int no_expand;
+	int error;
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
+		return -EOVERFLOW;
+
+	/*
+	 * In nojournal mode, we can immediately attempt to expand
+	 * the inode.  When journaled, we first need to obtain extra
+	 * buffer credits since we may write into the EA block
+	 * with this same handle. If journal_extend fails, then it will
+	 * only result in a minor loss of functionality for that inode.
+	 * If this is felt to be critical, then e2fsck should be run to
+	 * force a large enough s_min_extra_isize.
+	 */
+	if (ext4_journal_extend(handle,
+				EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
+		return -ENOSPC;
+
+	if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
+		return -EBUSY;
+
+	error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
+					  handle, &no_expand);
+	ext4_write_unlock_xattr(inode, &no_expand);
+
+	return error;
+}
+
+int ext4_expand_extra_isize(struct inode *inode,
+			    unsigned int new_extra_isize,
+			    struct ext4_iloc *iloc)
+{
+	handle_t *handle;
+	int no_expand;
+	int error, rc;
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
+		brelse(iloc->bh);
+		return -EOVERFLOW;
+	}
+
+	handle = ext4_journal_start(inode, EXT4_HT_INODE,
+				    EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
+	if (IS_ERR(handle)) {
+		error = PTR_ERR(handle);
+		brelse(iloc->bh);
+		return error;
+	}
+
+	ext4_write_lock_xattr(inode, &no_expand);
+
+	BUFFER_TRACE(iloc->bh, "get_write_access");
+	error = ext4_journal_get_write_access(handle, iloc->bh);
+	if (error) {
+		brelse(iloc->bh);
+		goto out_unlock;
+	}
+
+	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
+					  handle, &no_expand);
+
+	rc = ext4_mark_iloc_dirty(handle, inode, iloc);
+	if (!error)
+		error = rc;
+
+out_unlock:
+	ext4_write_unlock_xattr(inode, &no_expand);
+	ext4_journal_stop(handle);
+	return error;
+}
+
+/*
+ * What we do here is to mark the in-core inode as clean with respect to inode
+ * dirtiness (it may still be data-dirty).
+ * This means that the in-core inode may be reaped by prune_icache
+ * without having to perform any I/O.  This is a very good thing,
+ * because *any* task may call prune_icache - even ones which
+ * have a transaction open against a different journal.
+ *
+ * Is this cheating?  Not really.  Sure, we haven't written the
+ * inode out, but prune_icache isn't a user-visible syncing function.
+ * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
+ * we start and wait on commits.
+ */
+int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
+				const char *func, unsigned int line)
+{
+	struct ext4_iloc iloc;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int err;
+
+	might_sleep();
+	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
+	err = ext4_reserve_inode_write(handle, inode, &iloc);
+	if (err)
+		goto out;
+
+	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
+		ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
+					       iloc, handle);
+
+	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+out:
+	if (unlikely(err))
+		ext4_error_inode_err(inode, func, line, 0, err,
+					"mark_inode_dirty error");
+	return err;
+}
+
+/*
+ * ext4_dirty_inode() is called from __mark_inode_dirty()
+ *
+ * We're really interested in the case where a file is being extended.
+ * i_size has been changed by generic_commit_write() and we thus need
+ * to include the updated inode in the current transaction.
+ *
+ * Also, dquot_alloc_block() will always dirty the inode when blocks
+ * are allocated to the file.
+ *
+ * If the inode is marked synchronous, we don't honour that here - doing
+ * so would cause a commit on atime updates, which we don't bother doing.
+ * We handle synchronous inodes at the highest possible level.
+ *
+ * If only the I_DIRTY_TIME flag is set, we can skip everything.  If
+ * I_DIRTY_TIME and I_DIRTY_SYNC is set, the only inode fields we need
+ * to copy into the on-disk inode structure are the timestamp files.
+ */
+void ext4_dirty_inode(struct inode *inode, int flags)
+{
+	handle_t *handle;
+
+	if (flags == I_DIRTY_TIME)
+		return;
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+	if (IS_ERR(handle))
+		goto out;
+
+	ext4_mark_inode_dirty(handle, inode);
+
+	ext4_journal_stop(handle);
+out:
+	return;
+}
+
+int ext4_change_inode_journal_flag(struct inode *inode, int val)
+{
+	journal_t *journal;
+	handle_t *handle;
+	int err;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+	/*
+	 * We have to be very careful here: changing a data block's
+	 * journaling status dynamically is dangerous.  If we write a
+	 * data block to the journal, change the status and then delete
+	 * that block, we risk forgetting to revoke the old log record
+	 * from the journal and so a subsequent replay can corrupt data.
+	 * So, first we make sure that the journal is empty and that
+	 * nobody is changing anything.
+	 */
+
+	journal = EXT4_JOURNAL(inode);
+	if (!journal)
+		return 0;
+	if (is_journal_aborted(journal))
+		return -EROFS;
+
+	/* Wait for all existing dio workers */
+	inode_dio_wait(inode);
+
+	/*
+	 * Before flushing the journal and switching inode's aops, we have
+	 * to flush all dirty data the inode has. There can be outstanding
+	 * delayed allocations, there can be unwritten extents created by
+	 * fallocate or buffered writes in dioread_nolock mode covered by
+	 * dirty data which can be converted only after flushing the dirty
+	 * data (and journalled aops don't know how to handle these cases).
+	 */
+	if (val) {
+		down_write(&EXT4_I(inode)->i_mmap_sem);
+		err = filemap_write_and_wait(inode->i_mapping);
+		if (err < 0) {
+			up_write(&EXT4_I(inode)->i_mmap_sem);
+			return err;
+		}
+	}
+
+	percpu_down_write(&sbi->s_writepages_rwsem);
+	jbd2_journal_lock_updates(journal);
+
+	/*
+	 * OK, there are no updates running now, and all cached data is
+	 * synced to disk.  We are now in a completely consistent state
+	 * which doesn't have anything in the journal, and we know that
+	 * no filesystem updates are running, so it is safe to modify
+	 * the inode's in-core data-journaling state flag now.
+	 */
+
+	if (val)
+		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
+	else {
+		err = jbd2_journal_flush(journal);
+		if (err < 0) {
+			jbd2_journal_unlock_updates(journal);
+			percpu_up_write(&sbi->s_writepages_rwsem);
+			return err;
+		}
+		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
+	}
+	ext4_set_aops(inode);
+
+	jbd2_journal_unlock_updates(journal);
+	percpu_up_write(&sbi->s_writepages_rwsem);
+
+	if (val)
+		up_write(&EXT4_I(inode)->i_mmap_sem);
+
+	/* Finally we can mark the inode as dirty. */
+
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	ext4_fc_mark_ineligible(inode->i_sb,
+		EXT4_FC_REASON_JOURNAL_FLAG_CHANGE);
+	err = ext4_mark_inode_dirty(handle, inode);
+	ext4_handle_sync(handle);
+	ext4_journal_stop(handle);
+	ext4_std_error(inode->i_sb, err);
+
+	return err;
+}
+
+static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
+{
+	return !buffer_mapped(bh);
+}
+
+vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct page *page = vmf->page;
+	loff_t size;
+	unsigned long len;
+	int err;
+	vm_fault_t ret;
+	struct file *file = vma->vm_file;
+	struct inode *inode = file_inode(file);
+	struct address_space *mapping = inode->i_mapping;
+	handle_t *handle;
+	get_block_t *get_block;
+	int retries = 0;
+
+	if (unlikely(IS_IMMUTABLE(inode)))
+		return VM_FAULT_SIGBUS;
+
+	sb_start_pagefault(inode->i_sb);
+	file_update_time(vma->vm_file);
+
+	down_read(&EXT4_I(inode)->i_mmap_sem);
+
+	err = ext4_convert_inline_data(inode);
+	if (err)
+		goto out_ret;
+
+	/*
+	 * On data journalling we skip straight to the transaction handle:
+	 * there's no delalloc; page truncated will be checked later; the
+	 * early return w/ all buffers mapped (calculates size/len) can't
+	 * be used; and there's no dioread_nolock, so only ext4_get_block.
+	 */
+	if (ext4_should_journal_data(inode))
+		goto retry_alloc;
+
+	/* Delalloc case is easy... */
+	if (test_opt(inode->i_sb, DELALLOC) &&
+	    !ext4_nonda_switch(inode->i_sb)) {
+		do {
+			err = block_page_mkwrite(vma, vmf,
+						   ext4_da_get_block_prep);
+		} while (err == -ENOSPC &&
+		       ext4_should_retry_alloc(inode->i_sb, &retries));
+		goto out_ret;
+	}
+
+	lock_page(page);
+	size = i_size_read(inode);
+	/* Page got truncated from under us? */
+	if (page->mapping != mapping || page_offset(page) > size) {
+		unlock_page(page);
+		ret = VM_FAULT_NOPAGE;
+		goto out;
+	}
+
+	if (page->index == size >> PAGE_SHIFT)
+		len = size & ~PAGE_MASK;
+	else
+		len = PAGE_SIZE;
+	/*
+	 * Return if we have all the buffers mapped. This avoids the need to do
+	 * journal_start/journal_stop which can block and take a long time
+	 *
+	 * This cannot be done for data journalling, as we have to add the
+	 * inode to the transaction's list to writeprotect pages on commit.
+	 */
+	if (page_has_buffers(page)) {
+		if (!ext4_walk_page_buffers(NULL, page_buffers(page),
+					    0, len, NULL,
+					    ext4_bh_unmapped)) {
+			/* Wait so that we don't change page under IO */
+			wait_for_stable_page(page);
+			ret = VM_FAULT_LOCKED;
+			goto out;
+		}
+	}
+	unlock_page(page);
+	/* OK, we need to fill the hole... */
+	if (ext4_should_dioread_nolock(inode))
+		get_block = ext4_get_block_unwritten;
+	else
+		get_block = ext4_get_block;
+retry_alloc:
+	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
+				    ext4_writepage_trans_blocks(inode));
+	if (IS_ERR(handle)) {
+		ret = VM_FAULT_SIGBUS;
+		goto out;
+	}
+	/*
+	 * Data journalling can't use block_page_mkwrite() because it
+	 * will set_buffer_dirty() before do_journal_get_write_access()
+	 * thus might hit warning messages for dirty metadata buffers.
+	 */
+	if (!ext4_should_journal_data(inode)) {
+		err = block_page_mkwrite(vma, vmf, get_block);
+	} else {
+		lock_page(page);
+		size = i_size_read(inode);
+		/* Page got truncated from under us? */
+		if (page->mapping != mapping || page_offset(page) > size) {
+			ret = VM_FAULT_NOPAGE;
+			goto out_error;
+		}
+
+		if (page->index == size >> PAGE_SHIFT)
+			len = size & ~PAGE_MASK;
+		else
+			len = PAGE_SIZE;
+
+		err = __block_write_begin(page, 0, len, ext4_get_block);
+		if (!err) {
+			ret = VM_FAULT_SIGBUS;
+			if (ext4_walk_page_buffers(handle, page_buffers(page),
+					0, len, NULL, do_journal_get_write_access))
+				goto out_error;
+			if (ext4_walk_page_buffers(handle, page_buffers(page),
+					0, len, NULL, write_end_fn))
+				goto out_error;
+			if (ext4_jbd2_inode_add_write(handle, inode,
+						      page_offset(page), len))
+				goto out_error;
+			ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+		} else {
+			unlock_page(page);
+		}
+	}
+	ext4_journal_stop(handle);
+	if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry_alloc;
+out_ret:
+	ret = block_page_mkwrite_return(err);
+out:
+	up_read(&EXT4_I(inode)->i_mmap_sem);
+	sb_end_pagefault(inode->i_sb);
+	return ret;
+out_error:
+	unlock_page(page);
+	ext4_journal_stop(handle);
+	goto out;
+}
+
+vm_fault_t ext4_filemap_fault(struct vm_fault *vmf)
+{
+	struct inode *inode = file_inode(vmf->vma->vm_file);
+	vm_fault_t ret;
+
+	down_read(&EXT4_I(inode)->i_mmap_sem);
+	ret = filemap_fault(vmf);
+	up_read(&EXT4_I(inode)->i_mmap_sem);
+
+	return ret;
+}
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
new file mode 100644
index 000000000..56829507e
--- /dev/null
+++ b/fs/ext4/ioctl.c
@@ -0,0 +1,1408 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/ioctl.c
+ *
+ * Copyright (C) 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/fs.h>
+#include <linux/capability.h>
+#include <linux/time.h>
+#include <linux/compat.h>
+#include <linux/mount.h>
+#include <linux/file.h>
+#include <linux/quotaops.h>
+#include <linux/random.h>
+#include <linux/uuid.h>
+#include <linux/uaccess.h>
+#include <linux/delay.h>
+#include <linux/iversion.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include <linux/fsmap.h>
+#include "fsmap.h"
+#include <trace/events/ext4.h>
+
+/**
+ * Swap memory between @a and @b for @len bytes.
+ *
+ * @a:          pointer to first memory area
+ * @b:          pointer to second memory area
+ * @len:        number of bytes to swap
+ *
+ */
+static void memswap(void *a, void *b, size_t len)
+{
+	unsigned char *ap, *bp;
+
+	ap = (unsigned char *)a;
+	bp = (unsigned char *)b;
+	while (len-- > 0) {
+		swap(*ap, *bp);
+		ap++;
+		bp++;
+	}
+}
+
+/**
+ * Swap i_data and associated attributes between @inode1 and @inode2.
+ * This function is used for the primary swap between inode1 and inode2
+ * and also to revert this primary swap in case of errors.
+ *
+ * Therefore you have to make sure, that calling this method twice
+ * will revert all changes.
+ *
+ * @inode1:     pointer to first inode
+ * @inode2:     pointer to second inode
+ */
+static void swap_inode_data(struct inode *inode1, struct inode *inode2)
+{
+	loff_t isize;
+	struct ext4_inode_info *ei1;
+	struct ext4_inode_info *ei2;
+	unsigned long tmp;
+
+	ei1 = EXT4_I(inode1);
+	ei2 = EXT4_I(inode2);
+
+	swap(inode1->i_version, inode2->i_version);
+	swap(inode1->i_atime, inode2->i_atime);
+	swap(inode1->i_mtime, inode2->i_mtime);
+
+	memswap(ei1->i_data, ei2->i_data, sizeof(ei1->i_data));
+	tmp = ei1->i_flags & EXT4_FL_SHOULD_SWAP;
+	ei1->i_flags = (ei2->i_flags & EXT4_FL_SHOULD_SWAP) |
+		(ei1->i_flags & ~EXT4_FL_SHOULD_SWAP);
+	ei2->i_flags = tmp | (ei2->i_flags & ~EXT4_FL_SHOULD_SWAP);
+	swap(ei1->i_disksize, ei2->i_disksize);
+	ext4_es_remove_extent(inode1, 0, EXT_MAX_BLOCKS);
+	ext4_es_remove_extent(inode2, 0, EXT_MAX_BLOCKS);
+
+	isize = i_size_read(inode1);
+	i_size_write(inode1, i_size_read(inode2));
+	i_size_write(inode2, isize);
+}
+
+void ext4_reset_inode_seed(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	__le32 inum = cpu_to_le32(inode->i_ino);
+	__le32 gen = cpu_to_le32(inode->i_generation);
+	__u32 csum;
+
+	if (!ext4_has_metadata_csum(inode->i_sb))
+		return;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum, sizeof(inum));
+	ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen, sizeof(gen));
+}
+
+/**
+ * Swap the information from the given @inode and the inode
+ * EXT4_BOOT_LOADER_INO. It will basically swap i_data and all other
+ * important fields of the inodes.
+ *
+ * @sb:         the super block of the filesystem
+ * @inode:      the inode to swap with EXT4_BOOT_LOADER_INO
+ *
+ */
+static long swap_inode_boot_loader(struct super_block *sb,
+				struct inode *inode)
+{
+	handle_t *handle;
+	int err;
+	struct inode *inode_bl;
+	struct ext4_inode_info *ei_bl;
+	qsize_t size, size_bl, diff;
+	blkcnt_t blocks;
+	unsigned short bytes;
+
+	inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO,
+			EXT4_IGET_SPECIAL | EXT4_IGET_BAD);
+	if (IS_ERR(inode_bl))
+		return PTR_ERR(inode_bl);
+	ei_bl = EXT4_I(inode_bl);
+
+	/* Protect orig inodes against a truncate and make sure,
+	 * that only 1 swap_inode_boot_loader is running. */
+	lock_two_nondirectories(inode, inode_bl);
+
+	if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode) ||
+	    IS_SWAPFILE(inode) || IS_ENCRYPTED(inode) ||
+	    (EXT4_I(inode)->i_flags & EXT4_JOURNAL_DATA_FL) ||
+	    ext4_has_inline_data(inode)) {
+		err = -EINVAL;
+		goto journal_err_out;
+	}
+
+	if (IS_RDONLY(inode) || IS_APPEND(inode) || IS_IMMUTABLE(inode) ||
+	    !inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN)) {
+		err = -EPERM;
+		goto journal_err_out;
+	}
+
+	down_write(&EXT4_I(inode)->i_mmap_sem);
+	err = filemap_write_and_wait(inode->i_mapping);
+	if (err)
+		goto err_out;
+
+	err = filemap_write_and_wait(inode_bl->i_mapping);
+	if (err)
+		goto err_out;
+
+	/* Wait for all existing dio workers */
+	inode_dio_wait(inode);
+	inode_dio_wait(inode_bl);
+
+	truncate_inode_pages(&inode->i_data, 0);
+	truncate_inode_pages(&inode_bl->i_data, 0);
+
+	handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2);
+	if (IS_ERR(handle)) {
+		err = -EINVAL;
+		goto err_out;
+	}
+	ext4_fc_start_ineligible(sb, EXT4_FC_REASON_SWAP_BOOT);
+
+	/* Protect extent tree against block allocations via delalloc */
+	ext4_double_down_write_data_sem(inode, inode_bl);
+
+	if (is_bad_inode(inode_bl) || !S_ISREG(inode_bl->i_mode)) {
+		/* this inode has never been used as a BOOT_LOADER */
+		set_nlink(inode_bl, 1);
+		i_uid_write(inode_bl, 0);
+		i_gid_write(inode_bl, 0);
+		inode_bl->i_flags = 0;
+		ei_bl->i_flags = 0;
+		inode_set_iversion(inode_bl, 1);
+		i_size_write(inode_bl, 0);
+		EXT4_I(inode_bl)->i_disksize = inode_bl->i_size;
+		inode_bl->i_mode = S_IFREG;
+		if (ext4_has_feature_extents(sb)) {
+			ext4_set_inode_flag(inode_bl, EXT4_INODE_EXTENTS);
+			ext4_ext_tree_init(handle, inode_bl);
+		} else
+			memset(ei_bl->i_data, 0, sizeof(ei_bl->i_data));
+	}
+
+	err = dquot_initialize(inode);
+	if (err)
+		goto err_out1;
+
+	size = (qsize_t)(inode->i_blocks) * (1 << 9) + inode->i_bytes;
+	size_bl = (qsize_t)(inode_bl->i_blocks) * (1 << 9) + inode_bl->i_bytes;
+	diff = size - size_bl;
+	swap_inode_data(inode, inode_bl);
+
+	inode->i_ctime = inode_bl->i_ctime = current_time(inode);
+
+	inode->i_generation = prandom_u32();
+	inode_bl->i_generation = prandom_u32();
+	ext4_reset_inode_seed(inode);
+	ext4_reset_inode_seed(inode_bl);
+
+	ext4_discard_preallocations(inode, 0);
+
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (err < 0) {
+		/* No need to update quota information. */
+		ext4_warning(inode->i_sb,
+			"couldn't mark inode #%lu dirty (err %d)",
+			inode->i_ino, err);
+		/* Revert all changes: */
+		swap_inode_data(inode, inode_bl);
+		ext4_mark_inode_dirty(handle, inode);
+		goto err_out1;
+	}
+
+	blocks = inode_bl->i_blocks;
+	bytes = inode_bl->i_bytes;
+	inode_bl->i_blocks = inode->i_blocks;
+	inode_bl->i_bytes = inode->i_bytes;
+	err = ext4_mark_inode_dirty(handle, inode_bl);
+	if (err < 0) {
+		/* No need to update quota information. */
+		ext4_warning(inode_bl->i_sb,
+			"couldn't mark inode #%lu dirty (err %d)",
+			inode_bl->i_ino, err);
+		goto revert;
+	}
+
+	/* Bootloader inode should not be counted into quota information. */
+	if (diff > 0)
+		dquot_free_space(inode, diff);
+	else
+		err = dquot_alloc_space(inode, -1 * diff);
+
+	if (err < 0) {
+revert:
+		/* Revert all changes: */
+		inode_bl->i_blocks = blocks;
+		inode_bl->i_bytes = bytes;
+		swap_inode_data(inode, inode_bl);
+		ext4_mark_inode_dirty(handle, inode);
+		ext4_mark_inode_dirty(handle, inode_bl);
+	}
+
+err_out1:
+	ext4_journal_stop(handle);
+	ext4_fc_stop_ineligible(sb);
+	ext4_double_up_write_data_sem(inode, inode_bl);
+
+err_out:
+	up_write(&EXT4_I(inode)->i_mmap_sem);
+journal_err_out:
+	unlock_two_nondirectories(inode, inode_bl);
+	iput(inode_bl);
+	return err;
+}
+
+#ifdef CONFIG_FS_ENCRYPTION
+static int uuid_is_zero(__u8 u[16])
+{
+	int	i;
+
+	for (i = 0; i < 16; i++)
+		if (u[i])
+			return 0;
+	return 1;
+}
+#endif
+
+/*
+ * If immutable is set and we are not clearing it, we're not allowed to change
+ * anything else in the inode.  Don't error out if we're only trying to set
+ * immutable on an immutable file.
+ */
+static int ext4_ioctl_check_immutable(struct inode *inode, __u32 new_projid,
+				      unsigned int flags)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	unsigned int oldflags = ei->i_flags;
+
+	if (!(oldflags & EXT4_IMMUTABLE_FL) || !(flags & EXT4_IMMUTABLE_FL))
+		return 0;
+
+	if ((oldflags & ~EXT4_IMMUTABLE_FL) != (flags & ~EXT4_IMMUTABLE_FL))
+		return -EPERM;
+	if (ext4_has_feature_project(inode->i_sb) &&
+	    __kprojid_val(ei->i_projid) != new_projid)
+		return -EPERM;
+
+	return 0;
+}
+
+static void ext4_dax_dontcache(struct inode *inode, unsigned int flags)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (S_ISDIR(inode->i_mode))
+		return;
+
+	if (test_opt2(inode->i_sb, DAX_NEVER) ||
+	    test_opt(inode->i_sb, DAX_ALWAYS))
+		return;
+
+	if ((ei->i_flags ^ flags) & EXT4_DAX_FL)
+		d_mark_dontcache(inode);
+}
+
+static bool dax_compatible(struct inode *inode, unsigned int oldflags,
+			   unsigned int flags)
+{
+	/* Allow the DAX flag to be changed on inline directories */
+	if (S_ISDIR(inode->i_mode)) {
+		flags &= ~EXT4_INLINE_DATA_FL;
+		oldflags &= ~EXT4_INLINE_DATA_FL;
+	}
+
+	if (flags & EXT4_DAX_FL) {
+		if ((oldflags & EXT4_DAX_MUT_EXCL) ||
+		     ext4_test_inode_state(inode,
+					  EXT4_STATE_VERITY_IN_PROGRESS)) {
+			return false;
+		}
+	}
+
+	if ((flags & EXT4_DAX_MUT_EXCL) && (oldflags & EXT4_DAX_FL))
+			return false;
+
+	return true;
+}
+
+static int ext4_ioctl_setflags(struct inode *inode,
+			       unsigned int flags)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	handle_t *handle = NULL;
+	int err = -EPERM, migrate = 0;
+	struct ext4_iloc iloc;
+	unsigned int oldflags, mask, i;
+	struct super_block *sb = inode->i_sb;
+
+	/* Is it quota file? Do not allow user to mess with it */
+	if (ext4_is_quota_file(inode))
+		goto flags_out;
+
+	oldflags = ei->i_flags;
+
+	err = vfs_ioc_setflags_prepare(inode, oldflags, flags);
+	if (err)
+		goto flags_out;
+
+	/*
+	 * The JOURNAL_DATA flag can only be changed by
+	 * the relevant capability.
+	 */
+	if ((flags ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) {
+		if (!capable(CAP_SYS_RESOURCE))
+			goto flags_out;
+	}
+
+	if (!dax_compatible(inode, oldflags, flags)) {
+		err = -EOPNOTSUPP;
+		goto flags_out;
+	}
+
+	if ((flags ^ oldflags) & EXT4_EXTENTS_FL)
+		migrate = 1;
+
+	if ((flags ^ oldflags) & EXT4_CASEFOLD_FL) {
+		if (!ext4_has_feature_casefold(sb)) {
+			err = -EOPNOTSUPP;
+			goto flags_out;
+		}
+
+		if (!S_ISDIR(inode->i_mode)) {
+			err = -ENOTDIR;
+			goto flags_out;
+		}
+
+		if (!ext4_empty_dir(inode)) {
+			err = -ENOTEMPTY;
+			goto flags_out;
+		}
+	}
+
+	/*
+	 * Wait for all pending directio and then flush all the dirty pages
+	 * for this file.  The flush marks all the pages readonly, so any
+	 * subsequent attempt to write to the file (particularly mmap pages)
+	 * will come through the filesystem and fail.
+	 */
+	if (S_ISREG(inode->i_mode) && !IS_IMMUTABLE(inode) &&
+	    (flags & EXT4_IMMUTABLE_FL)) {
+		inode_dio_wait(inode);
+		err = filemap_write_and_wait(inode->i_mapping);
+		if (err)
+			goto flags_out;
+	}
+
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		goto flags_out;
+	}
+	if (IS_SYNC(inode))
+		ext4_handle_sync(handle);
+	err = ext4_reserve_inode_write(handle, inode, &iloc);
+	if (err)
+		goto flags_err;
+
+	ext4_dax_dontcache(inode, flags);
+
+	for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
+		if (!(mask & EXT4_FL_USER_MODIFIABLE))
+			continue;
+		/* These flags get special treatment later */
+		if (mask == EXT4_JOURNAL_DATA_FL || mask == EXT4_EXTENTS_FL)
+			continue;
+		if (mask & flags)
+			ext4_set_inode_flag(inode, i);
+		else
+			ext4_clear_inode_flag(inode, i);
+	}
+
+	ext4_set_inode_flags(inode, false);
+
+	inode->i_ctime = current_time(inode);
+
+	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+flags_err:
+	ext4_journal_stop(handle);
+	if (err)
+		goto flags_out;
+
+	if ((flags ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) {
+		/*
+		 * Changes to the journaling mode can cause unsafe changes to
+		 * S_DAX if the inode is DAX
+		 */
+		if (IS_DAX(inode)) {
+			err = -EBUSY;
+			goto flags_out;
+		}
+
+		err = ext4_change_inode_journal_flag(inode,
+						     flags & EXT4_JOURNAL_DATA_FL);
+		if (err)
+			goto flags_out;
+	}
+	if (migrate) {
+		if (flags & EXT4_EXTENTS_FL)
+			err = ext4_ext_migrate(inode);
+		else
+			err = ext4_ind_migrate(inode);
+	}
+
+flags_out:
+	return err;
+}
+
+#ifdef CONFIG_QUOTA
+static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
+{
+	struct inode *inode = file_inode(filp);
+	struct super_block *sb = inode->i_sb;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	int err, rc;
+	handle_t *handle;
+	kprojid_t kprojid;
+	struct ext4_iloc iloc;
+	struct ext4_inode *raw_inode;
+	struct dquot *transfer_to[MAXQUOTAS] = { };
+
+	if (!ext4_has_feature_project(sb)) {
+		if (projid != EXT4_DEF_PROJID)
+			return -EOPNOTSUPP;
+		else
+			return 0;
+	}
+
+	if (EXT4_INODE_SIZE(sb) <= EXT4_GOOD_OLD_INODE_SIZE)
+		return -EOPNOTSUPP;
+
+	kprojid = make_kprojid(&init_user_ns, (projid_t)projid);
+
+	if (projid_eq(kprojid, EXT4_I(inode)->i_projid))
+		return 0;
+
+	err = -EPERM;
+	/* Is it quota file? Do not allow user to mess with it */
+	if (ext4_is_quota_file(inode))
+		return err;
+
+	err = dquot_initialize(inode);
+	if (err)
+		return err;
+
+	err = ext4_get_inode_loc(inode, &iloc);
+	if (err)
+		return err;
+
+	raw_inode = ext4_raw_inode(&iloc);
+	if (!EXT4_FITS_IN_INODE(raw_inode, ei, i_projid)) {
+		err = ext4_expand_extra_isize(inode,
+					      EXT4_SB(sb)->s_want_extra_isize,
+					      &iloc);
+		if (err)
+			return err;
+	} else {
+		brelse(iloc.bh);
+	}
+
+	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
+		EXT4_QUOTA_INIT_BLOCKS(sb) +
+		EXT4_QUOTA_DEL_BLOCKS(sb) + 3);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	err = ext4_reserve_inode_write(handle, inode, &iloc);
+	if (err)
+		goto out_stop;
+
+	transfer_to[PRJQUOTA] = dqget(sb, make_kqid_projid(kprojid));
+	if (!IS_ERR(transfer_to[PRJQUOTA])) {
+
+		/* __dquot_transfer() calls back ext4_get_inode_usage() which
+		 * counts xattr inode references.
+		 */
+		down_read(&EXT4_I(inode)->xattr_sem);
+		err = __dquot_transfer(inode, transfer_to);
+		up_read(&EXT4_I(inode)->xattr_sem);
+		dqput(transfer_to[PRJQUOTA]);
+		if (err)
+			goto out_dirty;
+	}
+
+	EXT4_I(inode)->i_projid = kprojid;
+	inode->i_ctime = current_time(inode);
+out_dirty:
+	rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
+	if (!err)
+		err = rc;
+out_stop:
+	ext4_journal_stop(handle);
+	return err;
+}
+#else
+static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
+{
+	if (projid != EXT4_DEF_PROJID)
+		return -EOPNOTSUPP;
+	return 0;
+}
+#endif
+
+/* Transfer internal flags to xflags */
+static inline __u32 ext4_iflags_to_xflags(unsigned long iflags)
+{
+	__u32 xflags = 0;
+
+	if (iflags & EXT4_SYNC_FL)
+		xflags |= FS_XFLAG_SYNC;
+	if (iflags & EXT4_IMMUTABLE_FL)
+		xflags |= FS_XFLAG_IMMUTABLE;
+	if (iflags & EXT4_APPEND_FL)
+		xflags |= FS_XFLAG_APPEND;
+	if (iflags & EXT4_NODUMP_FL)
+		xflags |= FS_XFLAG_NODUMP;
+	if (iflags & EXT4_NOATIME_FL)
+		xflags |= FS_XFLAG_NOATIME;
+	if (iflags & EXT4_PROJINHERIT_FL)
+		xflags |= FS_XFLAG_PROJINHERIT;
+	if (iflags & EXT4_DAX_FL)
+		xflags |= FS_XFLAG_DAX;
+	return xflags;
+}
+
+#define EXT4_SUPPORTED_FS_XFLAGS (FS_XFLAG_SYNC | FS_XFLAG_IMMUTABLE | \
+				  FS_XFLAG_APPEND | FS_XFLAG_NODUMP | \
+				  FS_XFLAG_NOATIME | FS_XFLAG_PROJINHERIT | \
+				  FS_XFLAG_DAX)
+
+/* Transfer xflags flags to internal */
+static inline unsigned long ext4_xflags_to_iflags(__u32 xflags)
+{
+	unsigned long iflags = 0;
+
+	if (xflags & FS_XFLAG_SYNC)
+		iflags |= EXT4_SYNC_FL;
+	if (xflags & FS_XFLAG_IMMUTABLE)
+		iflags |= EXT4_IMMUTABLE_FL;
+	if (xflags & FS_XFLAG_APPEND)
+		iflags |= EXT4_APPEND_FL;
+	if (xflags & FS_XFLAG_NODUMP)
+		iflags |= EXT4_NODUMP_FL;
+	if (xflags & FS_XFLAG_NOATIME)
+		iflags |= EXT4_NOATIME_FL;
+	if (xflags & FS_XFLAG_PROJINHERIT)
+		iflags |= EXT4_PROJINHERIT_FL;
+	if (xflags & FS_XFLAG_DAX)
+		iflags |= EXT4_DAX_FL;
+
+	return iflags;
+}
+
+static int ext4_shutdown(struct super_block *sb, unsigned long arg)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	__u32 flags;
+	struct super_block *ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (get_user(flags, (__u32 __user *)arg))
+		return -EFAULT;
+
+	if (flags > EXT4_GOING_FLAGS_NOLOGFLUSH)
+		return -EINVAL;
+
+	if (ext4_forced_shutdown(sbi))
+		return 0;
+
+	ext4_msg(sb, KERN_ALERT, "shut down requested (%d)", flags);
+	trace_ext4_shutdown(sb, flags);
+
+	switch (flags) {
+	case EXT4_GOING_FLAGS_DEFAULT:
+		ret = freeze_bdev(sb->s_bdev);
+		if (IS_ERR(ret))
+			return PTR_ERR(ret);
+		set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
+		thaw_bdev(sb->s_bdev, sb);
+		break;
+	case EXT4_GOING_FLAGS_LOGFLUSH:
+		set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
+		if (sbi->s_journal && !is_journal_aborted(sbi->s_journal)) {
+			(void) ext4_force_commit(sb);
+			jbd2_journal_abort(sbi->s_journal, -ESHUTDOWN);
+		}
+		break;
+	case EXT4_GOING_FLAGS_NOLOGFLUSH:
+		set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
+		if (sbi->s_journal && !is_journal_aborted(sbi->s_journal))
+			jbd2_journal_abort(sbi->s_journal, -ESHUTDOWN);
+		break;
+	default:
+		return -EINVAL;
+	}
+	clear_opt(sb, DISCARD);
+	return 0;
+}
+
+struct getfsmap_info {
+	struct super_block	*gi_sb;
+	struct fsmap_head __user *gi_data;
+	unsigned int		gi_idx;
+	__u32			gi_last_flags;
+};
+
+static int ext4_getfsmap_format(struct ext4_fsmap *xfm, void *priv)
+{
+	struct getfsmap_info *info = priv;
+	struct fsmap fm;
+
+	trace_ext4_getfsmap_mapping(info->gi_sb, xfm);
+
+	info->gi_last_flags = xfm->fmr_flags;
+	ext4_fsmap_from_internal(info->gi_sb, &fm, xfm);
+	if (copy_to_user(&info->gi_data->fmh_recs[info->gi_idx++], &fm,
+			sizeof(struct fsmap)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int ext4_ioc_getfsmap(struct super_block *sb,
+			     struct fsmap_head __user *arg)
+{
+	struct getfsmap_info info = { NULL };
+	struct ext4_fsmap_head xhead = {0};
+	struct fsmap_head head;
+	bool aborted = false;
+	int error;
+
+	if (copy_from_user(&head, arg, sizeof(struct fsmap_head)))
+		return -EFAULT;
+	if (memchr_inv(head.fmh_reserved, 0, sizeof(head.fmh_reserved)) ||
+	    memchr_inv(head.fmh_keys[0].fmr_reserved, 0,
+		       sizeof(head.fmh_keys[0].fmr_reserved)) ||
+	    memchr_inv(head.fmh_keys[1].fmr_reserved, 0,
+		       sizeof(head.fmh_keys[1].fmr_reserved)))
+		return -EINVAL;
+	/*
+	 * ext4 doesn't report file extents at all, so the only valid
+	 * file offsets are the magic ones (all zeroes or all ones).
+	 */
+	if (head.fmh_keys[0].fmr_offset ||
+	    (head.fmh_keys[1].fmr_offset != 0 &&
+	     head.fmh_keys[1].fmr_offset != -1ULL))
+		return -EINVAL;
+
+	xhead.fmh_iflags = head.fmh_iflags;
+	xhead.fmh_count = head.fmh_count;
+	ext4_fsmap_to_internal(sb, &xhead.fmh_keys[0], &head.fmh_keys[0]);
+	ext4_fsmap_to_internal(sb, &xhead.fmh_keys[1], &head.fmh_keys[1]);
+
+	trace_ext4_getfsmap_low_key(sb, &xhead.fmh_keys[0]);
+	trace_ext4_getfsmap_high_key(sb, &xhead.fmh_keys[1]);
+
+	info.gi_sb = sb;
+	info.gi_data = arg;
+	error = ext4_getfsmap(sb, &xhead, ext4_getfsmap_format, &info);
+	if (error == EXT4_QUERY_RANGE_ABORT) {
+		error = 0;
+		aborted = true;
+	} else if (error)
+		return error;
+
+	/* If we didn't abort, set the "last" flag in the last fmx */
+	if (!aborted && info.gi_idx) {
+		info.gi_last_flags |= FMR_OF_LAST;
+		if (copy_to_user(&info.gi_data->fmh_recs[info.gi_idx - 1].fmr_flags,
+				 &info.gi_last_flags,
+				 sizeof(info.gi_last_flags)))
+			return -EFAULT;
+	}
+
+	/* copy back header */
+	head.fmh_entries = xhead.fmh_entries;
+	head.fmh_oflags = xhead.fmh_oflags;
+	if (copy_to_user(arg, &head, sizeof(struct fsmap_head)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ext4_ioctl_group_add(struct file *file,
+				 struct ext4_new_group_data *input)
+{
+	struct super_block *sb = file_inode(file)->i_sb;
+	int err, err2=0;
+
+	err = ext4_resize_begin(sb);
+	if (err)
+		return err;
+
+	if (ext4_has_feature_bigalloc(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Online resizing not supported with bigalloc");
+		err = -EOPNOTSUPP;
+		goto group_add_out;
+	}
+
+	err = mnt_want_write_file(file);
+	if (err)
+		goto group_add_out;
+
+	err = ext4_group_add(sb, input);
+	if (EXT4_SB(sb)->s_journal) {
+		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+		err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+	}
+	if (err == 0)
+		err = err2;
+	mnt_drop_write_file(file);
+	if (!err && ext4_has_group_desc_csum(sb) &&
+	    test_opt(sb, INIT_INODE_TABLE))
+		err = ext4_register_li_request(sb, input->group);
+group_add_out:
+	ext4_resize_end(sb);
+	return err;
+}
+
+static void ext4_fill_fsxattr(struct inode *inode, struct fsxattr *fa)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	simple_fill_fsxattr(fa, ext4_iflags_to_xflags(ei->i_flags &
+						      EXT4_FL_USER_VISIBLE));
+
+	if (ext4_has_feature_project(inode->i_sb))
+		fa->fsx_projid = from_kprojid(&init_user_ns, ei->i_projid);
+}
+
+/* So that the fiemap access checks can't overflow on 32 bit machines. */
+#define FIEMAP_MAX_EXTENTS	(UINT_MAX / sizeof(struct fiemap_extent))
+
+static int ext4_ioctl_get_es_cache(struct file *filp, unsigned long arg)
+{
+	struct fiemap fiemap;
+	struct fiemap __user *ufiemap = (struct fiemap __user *) arg;
+	struct fiemap_extent_info fieinfo = { 0, };
+	struct inode *inode = file_inode(filp);
+	int error;
+
+	if (copy_from_user(&fiemap, ufiemap, sizeof(fiemap)))
+		return -EFAULT;
+
+	if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
+		return -EINVAL;
+
+	fieinfo.fi_flags = fiemap.fm_flags;
+	fieinfo.fi_extents_max = fiemap.fm_extent_count;
+	fieinfo.fi_extents_start = ufiemap->fm_extents;
+
+	error = ext4_get_es_cache(inode, &fieinfo, fiemap.fm_start,
+			fiemap.fm_length);
+	fiemap.fm_flags = fieinfo.fi_flags;
+	fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
+	if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap)))
+		error = -EFAULT;
+
+	return error;
+}
+
+static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	struct super_block *sb = inode->i_sb;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	unsigned int flags;
+
+	ext4_debug("cmd = %u, arg = %lu\n", cmd, arg);
+
+	switch (cmd) {
+	case FS_IOC_GETFSMAP:
+		return ext4_ioc_getfsmap(sb, (void __user *)arg);
+	case FS_IOC_GETFLAGS:
+		flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
+		if (S_ISREG(inode->i_mode))
+			flags &= ~EXT4_PROJINHERIT_FL;
+		return put_user(flags, (int __user *) arg);
+	case FS_IOC_SETFLAGS: {
+		int err;
+
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		if (get_user(flags, (int __user *) arg))
+			return -EFAULT;
+
+		if (flags & ~EXT4_FL_USER_VISIBLE)
+			return -EOPNOTSUPP;
+		/*
+		 * chattr(1) grabs flags via GETFLAGS, modifies the result and
+		 * passes that to SETFLAGS. So we cannot easily make SETFLAGS
+		 * more restrictive than just silently masking off visible but
+		 * not settable flags as we always did.
+		 */
+		flags &= EXT4_FL_USER_MODIFIABLE;
+		if (ext4_mask_flags(inode->i_mode, flags) != flags)
+			return -EOPNOTSUPP;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+
+		inode_lock(inode);
+		err = ext4_ioctl_check_immutable(inode,
+				from_kprojid(&init_user_ns, ei->i_projid),
+				flags);
+		if (!err)
+			err = ext4_ioctl_setflags(inode, flags);
+		inode_unlock(inode);
+		mnt_drop_write_file(filp);
+		return err;
+	}
+	case EXT4_IOC_GETVERSION:
+	case EXT4_IOC_GETVERSION_OLD:
+		return put_user(inode->i_generation, (int __user *) arg);
+	case EXT4_IOC_SETVERSION:
+	case EXT4_IOC_SETVERSION_OLD: {
+		handle_t *handle;
+		struct ext4_iloc iloc;
+		__u32 generation;
+		int err;
+
+		if (!inode_owner_or_capable(inode))
+			return -EPERM;
+
+		if (ext4_has_metadata_csum(inode->i_sb)) {
+			ext4_warning(sb, "Setting inode version is not "
+				     "supported with metadata_csum enabled.");
+			return -ENOTTY;
+		}
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		if (get_user(generation, (int __user *) arg)) {
+			err = -EFAULT;
+			goto setversion_out;
+		}
+
+		inode_lock(inode);
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+		if (IS_ERR(handle)) {
+			err = PTR_ERR(handle);
+			goto unlock_out;
+		}
+		err = ext4_reserve_inode_write(handle, inode, &iloc);
+		if (err == 0) {
+			inode->i_ctime = current_time(inode);
+			inode->i_generation = generation;
+			err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+		}
+		ext4_journal_stop(handle);
+
+unlock_out:
+		inode_unlock(inode);
+setversion_out:
+		mnt_drop_write_file(filp);
+		return err;
+	}
+	case EXT4_IOC_GROUP_EXTEND: {
+		ext4_fsblk_t n_blocks_count;
+		int err, err2=0;
+
+		err = ext4_resize_begin(sb);
+		if (err)
+			return err;
+
+		if (get_user(n_blocks_count, (__u32 __user *)arg)) {
+			err = -EFAULT;
+			goto group_extend_out;
+		}
+
+		if (ext4_has_feature_bigalloc(sb)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online resizing not supported with bigalloc");
+			err = -EOPNOTSUPP;
+			goto group_extend_out;
+		}
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			goto group_extend_out;
+
+		err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count);
+		if (EXT4_SB(sb)->s_journal) {
+			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+		}
+		if (err == 0)
+			err = err2;
+		mnt_drop_write_file(filp);
+group_extend_out:
+		ext4_resize_end(sb);
+		return err;
+	}
+
+	case EXT4_IOC_MOVE_EXT: {
+		struct move_extent me;
+		struct fd donor;
+		int err;
+
+		if (!(filp->f_mode & FMODE_READ) ||
+		    !(filp->f_mode & FMODE_WRITE))
+			return -EBADF;
+
+		if (copy_from_user(&me,
+			(struct move_extent __user *)arg, sizeof(me)))
+			return -EFAULT;
+		me.moved_len = 0;
+
+		donor = fdget(me.donor_fd);
+		if (!donor.file)
+			return -EBADF;
+
+		if (!(donor.file->f_mode & FMODE_WRITE)) {
+			err = -EBADF;
+			goto mext_out;
+		}
+
+		if (ext4_has_feature_bigalloc(sb)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online defrag not supported with bigalloc");
+			err = -EOPNOTSUPP;
+			goto mext_out;
+		} else if (IS_DAX(inode)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online defrag not supported with DAX");
+			err = -EOPNOTSUPP;
+			goto mext_out;
+		}
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			goto mext_out;
+
+		err = ext4_move_extents(filp, donor.file, me.orig_start,
+					me.donor_start, me.len, &me.moved_len);
+		mnt_drop_write_file(filp);
+
+		if (copy_to_user((struct move_extent __user *)arg,
+				 &me, sizeof(me)))
+			err = -EFAULT;
+mext_out:
+		fdput(donor);
+		return err;
+	}
+
+	case EXT4_IOC_GROUP_ADD: {
+		struct ext4_new_group_data input;
+
+		if (copy_from_user(&input, (struct ext4_new_group_input __user *)arg,
+				sizeof(input)))
+			return -EFAULT;
+
+		return ext4_ioctl_group_add(filp, &input);
+	}
+
+	case EXT4_IOC_MIGRATE:
+	{
+		int err;
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		/*
+		 * inode_mutex prevent write and truncate on the file.
+		 * Read still goes through. We take i_data_sem in
+		 * ext4_ext_swap_inode_data before we switch the
+		 * inode format to prevent read.
+		 */
+		inode_lock((inode));
+		err = ext4_ext_migrate(inode);
+		inode_unlock((inode));
+		mnt_drop_write_file(filp);
+		return err;
+	}
+
+	case EXT4_IOC_ALLOC_DA_BLKS:
+	{
+		int err;
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		err = ext4_alloc_da_blocks(inode);
+		mnt_drop_write_file(filp);
+		return err;
+	}
+
+	case EXT4_IOC_SWAP_BOOT:
+	{
+		int err;
+		if (!(filp->f_mode & FMODE_WRITE))
+			return -EBADF;
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		err = swap_inode_boot_loader(sb, inode);
+		mnt_drop_write_file(filp);
+		return err;
+	}
+
+	case EXT4_IOC_RESIZE_FS: {
+		ext4_fsblk_t n_blocks_count;
+		int err = 0, err2 = 0;
+		ext4_group_t o_group = EXT4_SB(sb)->s_groups_count;
+
+		if (copy_from_user(&n_blocks_count, (__u64 __user *)arg,
+				   sizeof(__u64))) {
+			return -EFAULT;
+		}
+
+		err = ext4_resize_begin(sb);
+		if (err)
+			return err;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			goto resizefs_out;
+
+		err = ext4_resize_fs(sb, n_blocks_count);
+		if (EXT4_SB(sb)->s_journal) {
+			ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_RESIZE);
+			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+		}
+		if (err == 0)
+			err = err2;
+		mnt_drop_write_file(filp);
+		if (!err && (o_group < EXT4_SB(sb)->s_groups_count) &&
+		    ext4_has_group_desc_csum(sb) &&
+		    test_opt(sb, INIT_INODE_TABLE))
+			err = ext4_register_li_request(sb, o_group);
+
+resizefs_out:
+		ext4_resize_end(sb);
+		return err;
+	}
+
+	case FITRIM:
+	{
+		struct request_queue *q = bdev_get_queue(sb->s_bdev);
+		struct fstrim_range range;
+		int ret = 0;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		if (!blk_queue_discard(q))
+			return -EOPNOTSUPP;
+
+		/*
+		 * We haven't replayed the journal, so we cannot use our
+		 * block-bitmap-guided storage zapping commands.
+		 */
+		if (test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb))
+			return -EROFS;
+
+		if (copy_from_user(&range, (struct fstrim_range __user *)arg,
+		    sizeof(range)))
+			return -EFAULT;
+
+		ret = ext4_trim_fs(sb, &range);
+		if (ret < 0)
+			return ret;
+
+		if (copy_to_user((struct fstrim_range __user *)arg, &range,
+		    sizeof(range)))
+			return -EFAULT;
+
+		return 0;
+	}
+	case EXT4_IOC_PRECACHE_EXTENTS:
+		return ext4_ext_precache(inode);
+
+	case FS_IOC_SET_ENCRYPTION_POLICY:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_set_policy(filp, (const void __user *)arg);
+
+	case FS_IOC_GET_ENCRYPTION_PWSALT: {
+#ifdef CONFIG_FS_ENCRYPTION
+		int err, err2;
+		struct ext4_sb_info *sbi = EXT4_SB(sb);
+		handle_t *handle;
+
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
+			err = mnt_want_write_file(filp);
+			if (err)
+				return err;
+			handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+			if (IS_ERR(handle)) {
+				err = PTR_ERR(handle);
+				goto pwsalt_err_exit;
+			}
+			err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+			if (err)
+				goto pwsalt_err_journal;
+			lock_buffer(sbi->s_sbh);
+			generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);
+			ext4_superblock_csum_set(sb);
+			unlock_buffer(sbi->s_sbh);
+			err = ext4_handle_dirty_metadata(handle, NULL,
+							 sbi->s_sbh);
+		pwsalt_err_journal:
+			err2 = ext4_journal_stop(handle);
+			if (err2 && !err)
+				err = err2;
+		pwsalt_err_exit:
+			mnt_drop_write_file(filp);
+			if (err)
+				return err;
+		}
+		if (copy_to_user((void __user *) arg,
+				 sbi->s_es->s_encrypt_pw_salt, 16))
+			return -EFAULT;
+		return 0;
+#else
+		return -EOPNOTSUPP;
+#endif
+	}
+	case FS_IOC_GET_ENCRYPTION_POLICY:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
+
+	case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_get_policy_ex(filp, (void __user *)arg);
+
+	case FS_IOC_ADD_ENCRYPTION_KEY:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_add_key(filp, (void __user *)arg);
+
+	case FS_IOC_REMOVE_ENCRYPTION_KEY:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_remove_key(filp, (void __user *)arg);
+
+	case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_remove_key_all_users(filp,
+							  (void __user *)arg);
+	case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_get_key_status(filp, (void __user *)arg);
+
+	case FS_IOC_GET_ENCRYPTION_NONCE:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_get_nonce(filp, (void __user *)arg);
+
+	case EXT4_IOC_CLEAR_ES_CACHE:
+	{
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+		ext4_clear_inode_es(inode);
+		return 0;
+	}
+
+	case EXT4_IOC_GETSTATE:
+	{
+		__u32	state = 0;
+
+		if (ext4_test_inode_state(inode, EXT4_STATE_EXT_PRECACHED))
+			state |= EXT4_STATE_FLAG_EXT_PRECACHED;
+		if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
+			state |= EXT4_STATE_FLAG_NEW;
+		if (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY))
+			state |= EXT4_STATE_FLAG_NEWENTRY;
+		if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE))
+			state |= EXT4_STATE_FLAG_DA_ALLOC_CLOSE;
+
+		return put_user(state, (__u32 __user *) arg);
+	}
+
+	case EXT4_IOC_GET_ES_CACHE:
+		return ext4_ioctl_get_es_cache(filp, arg);
+
+	case FS_IOC_FSGETXATTR:
+	{
+		struct fsxattr fa;
+
+		ext4_fill_fsxattr(inode, &fa);
+
+		if (copy_to_user((struct fsxattr __user *)arg,
+				 &fa, sizeof(fa)))
+			return -EFAULT;
+		return 0;
+	}
+	case FS_IOC_FSSETXATTR:
+	{
+		struct fsxattr fa, old_fa;
+		int err;
+
+		if (copy_from_user(&fa, (struct fsxattr __user *)arg,
+				   sizeof(fa)))
+			return -EFAULT;
+
+		/* Make sure caller has proper permission */
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		if (fa.fsx_xflags & ~EXT4_SUPPORTED_FS_XFLAGS)
+			return -EOPNOTSUPP;
+
+		flags = ext4_xflags_to_iflags(fa.fsx_xflags);
+		if (ext4_mask_flags(inode->i_mode, flags) != flags)
+			return -EOPNOTSUPP;
+
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+
+		inode_lock(inode);
+		ext4_fill_fsxattr(inode, &old_fa);
+		err = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
+		if (err)
+			goto out;
+		flags = (ei->i_flags & ~EXT4_FL_XFLAG_VISIBLE) |
+			 (flags & EXT4_FL_XFLAG_VISIBLE);
+		err = ext4_ioctl_check_immutable(inode, fa.fsx_projid, flags);
+		if (err)
+			goto out;
+		err = ext4_ioctl_setflags(inode, flags);
+		if (err)
+			goto out;
+		err = ext4_ioctl_setproject(filp, fa.fsx_projid);
+out:
+		inode_unlock(inode);
+		mnt_drop_write_file(filp);
+		return err;
+	}
+	case EXT4_IOC_SHUTDOWN:
+		return ext4_shutdown(sb, arg);
+
+	case FS_IOC_ENABLE_VERITY:
+		if (!ext4_has_feature_verity(sb))
+			return -EOPNOTSUPP;
+		return fsverity_ioctl_enable(filp, (const void __user *)arg);
+
+	case FS_IOC_MEASURE_VERITY:
+		if (!ext4_has_feature_verity(sb))
+			return -EOPNOTSUPP;
+		return fsverity_ioctl_measure(filp, (void __user *)arg);
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	return __ext4_ioctl(filp, cmd, arg);
+}
+
+#ifdef CONFIG_COMPAT
+long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	/* These are just misnamed, they actually get/put from/to user an int */
+	switch (cmd) {
+	case FS_IOC32_GETFLAGS:
+		cmd = FS_IOC_GETFLAGS;
+		break;
+	case FS_IOC32_SETFLAGS:
+		cmd = FS_IOC_SETFLAGS;
+		break;
+	case EXT4_IOC32_GETVERSION:
+		cmd = EXT4_IOC_GETVERSION;
+		break;
+	case EXT4_IOC32_SETVERSION:
+		cmd = EXT4_IOC_SETVERSION;
+		break;
+	case EXT4_IOC32_GROUP_EXTEND:
+		cmd = EXT4_IOC_GROUP_EXTEND;
+		break;
+	case EXT4_IOC32_GETVERSION_OLD:
+		cmd = EXT4_IOC_GETVERSION_OLD;
+		break;
+	case EXT4_IOC32_SETVERSION_OLD:
+		cmd = EXT4_IOC_SETVERSION_OLD;
+		break;
+	case EXT4_IOC32_GETRSVSZ:
+		cmd = EXT4_IOC_GETRSVSZ;
+		break;
+	case EXT4_IOC32_SETRSVSZ:
+		cmd = EXT4_IOC_SETRSVSZ;
+		break;
+	case EXT4_IOC32_GROUP_ADD: {
+		struct compat_ext4_new_group_input __user *uinput;
+		struct ext4_new_group_data input;
+		int err;
+
+		uinput = compat_ptr(arg);
+		err = get_user(input.group, &uinput->group);
+		err |= get_user(input.block_bitmap, &uinput->block_bitmap);
+		err |= get_user(input.inode_bitmap, &uinput->inode_bitmap);
+		err |= get_user(input.inode_table, &uinput->inode_table);
+		err |= get_user(input.blocks_count, &uinput->blocks_count);
+		err |= get_user(input.reserved_blocks,
+				&uinput->reserved_blocks);
+		if (err)
+			return -EFAULT;
+		return ext4_ioctl_group_add(file, &input);
+	}
+	case EXT4_IOC_MOVE_EXT:
+	case EXT4_IOC_RESIZE_FS:
+	case FITRIM:
+	case EXT4_IOC_PRECACHE_EXTENTS:
+	case FS_IOC_SET_ENCRYPTION_POLICY:
+	case FS_IOC_GET_ENCRYPTION_PWSALT:
+	case FS_IOC_GET_ENCRYPTION_POLICY:
+	case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+	case FS_IOC_ADD_ENCRYPTION_KEY:
+	case FS_IOC_REMOVE_ENCRYPTION_KEY:
+	case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+	case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
+	case FS_IOC_GET_ENCRYPTION_NONCE:
+	case EXT4_IOC_SHUTDOWN:
+	case FS_IOC_GETFSMAP:
+	case FS_IOC_ENABLE_VERITY:
+	case FS_IOC_MEASURE_VERITY:
+	case EXT4_IOC_CLEAR_ES_CACHE:
+	case EXT4_IOC_GETSTATE:
+	case EXT4_IOC_GET_ES_CACHE:
+	case FS_IOC_FSGETXATTR:
+	case FS_IOC_FSSETXATTR:
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+	return ext4_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
+}
+#endif
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
new file mode 100644
index 000000000..3babc07ae
--- /dev/null
+++ b/fs/ext4/mballoc.c
@@ -0,0 +1,6160 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
+ * Written by Alex Tomas <alex@clusterfs.com>
+ */
+
+
+/*
+ * mballoc.c contains the multiblocks allocation routines
+ */
+
+#include "ext4_jbd2.h"
+#include "mballoc.h"
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/nospec.h>
+#include <linux/backing-dev.h>
+#include <linux/freezer.h>
+#include <trace/events/ext4.h>
+
+/*
+ * MUSTDO:
+ *   - test ext4_ext_search_left() and ext4_ext_search_right()
+ *   - search for metadata in few groups
+ *
+ * TODO v4:
+ *   - normalization should take into account whether file is still open
+ *   - discard preallocations if no free space left (policy?)
+ *   - don't normalize tails
+ *   - quota
+ *   - reservation for superuser
+ *
+ * TODO v3:
+ *   - bitmap read-ahead (proposed by Oleg Drokin aka green)
+ *   - track min/max extents in each group for better group selection
+ *   - mb_mark_used() may allocate chunk right after splitting buddy
+ *   - tree of groups sorted by number of free blocks
+ *   - error handling
+ */
+
+/*
+ * The allocation request involve request for multiple number of blocks
+ * near to the goal(block) value specified.
+ *
+ * During initialization phase of the allocator we decide to use the
+ * group preallocation or inode preallocation depending on the size of
+ * the file. The size of the file could be the resulting file size we
+ * would have after allocation, or the current file size, which ever
+ * is larger. If the size is less than sbi->s_mb_stream_request we
+ * select to use the group preallocation. The default value of
+ * s_mb_stream_request is 16 blocks. This can also be tuned via
+ * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
+ * terms of number of blocks.
+ *
+ * The main motivation for having small file use group preallocation is to
+ * ensure that we have small files closer together on the disk.
+ *
+ * First stage the allocator looks at the inode prealloc list,
+ * ext4_inode_info->i_prealloc_list, which contains list of prealloc
+ * spaces for this particular inode. The inode prealloc space is
+ * represented as:
+ *
+ * pa_lstart -> the logical start block for this prealloc space
+ * pa_pstart -> the physical start block for this prealloc space
+ * pa_len    -> length for this prealloc space (in clusters)
+ * pa_free   ->  free space available in this prealloc space (in clusters)
+ *
+ * The inode preallocation space is used looking at the _logical_ start
+ * block. If only the logical file block falls within the range of prealloc
+ * space we will consume the particular prealloc space. This makes sure that
+ * we have contiguous physical blocks representing the file blocks
+ *
+ * The important thing to be noted in case of inode prealloc space is that
+ * we don't modify the values associated to inode prealloc space except
+ * pa_free.
+ *
+ * If we are not able to find blocks in the inode prealloc space and if we
+ * have the group allocation flag set then we look at the locality group
+ * prealloc space. These are per CPU prealloc list represented as
+ *
+ * ext4_sb_info.s_locality_groups[smp_processor_id()]
+ *
+ * The reason for having a per cpu locality group is to reduce the contention
+ * between CPUs. It is possible to get scheduled at this point.
+ *
+ * The locality group prealloc space is used looking at whether we have
+ * enough free space (pa_free) within the prealloc space.
+ *
+ * If we can't allocate blocks via inode prealloc or/and locality group
+ * prealloc then we look at the buddy cache. The buddy cache is represented
+ * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
+ * mapped to the buddy and bitmap information regarding different
+ * groups. The buddy information is attached to buddy cache inode so that
+ * we can access them through the page cache. The information regarding
+ * each group is loaded via ext4_mb_load_buddy.  The information involve
+ * block bitmap and buddy information. The information are stored in the
+ * inode as:
+ *
+ *  {                        page                        }
+ *  [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
+ *
+ *
+ * one block each for bitmap and buddy information.  So for each group we
+ * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
+ * blocksize) blocks.  So it can have information regarding groups_per_page
+ * which is blocks_per_page/2
+ *
+ * The buddy cache inode is not stored on disk. The inode is thrown
+ * away when the filesystem is unmounted.
+ *
+ * We look for count number of blocks in the buddy cache. If we were able
+ * to locate that many free blocks we return with additional information
+ * regarding rest of the contiguous physical block available
+ *
+ * Before allocating blocks via buddy cache we normalize the request
+ * blocks. This ensure we ask for more blocks that we needed. The extra
+ * blocks that we get after allocation is added to the respective prealloc
+ * list. In case of inode preallocation we follow a list of heuristics
+ * based on file size. This can be found in ext4_mb_normalize_request. If
+ * we are doing a group prealloc we try to normalize the request to
+ * sbi->s_mb_group_prealloc.  The default value of s_mb_group_prealloc is
+ * dependent on the cluster size; for non-bigalloc file systems, it is
+ * 512 blocks. This can be tuned via
+ * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
+ * terms of number of blocks. If we have mounted the file system with -O
+ * stripe=<value> option the group prealloc request is normalized to the
+ * smallest multiple of the stripe value (sbi->s_stripe) which is
+ * greater than the default mb_group_prealloc.
+ *
+ * The regular allocator (using the buddy cache) supports a few tunables.
+ *
+ * /sys/fs/ext4/<partition>/mb_min_to_scan
+ * /sys/fs/ext4/<partition>/mb_max_to_scan
+ * /sys/fs/ext4/<partition>/mb_order2_req
+ *
+ * The regular allocator uses buddy scan only if the request len is power of
+ * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
+ * value of s_mb_order2_reqs can be tuned via
+ * /sys/fs/ext4/<partition>/mb_order2_req.  If the request len is equal to
+ * stripe size (sbi->s_stripe), we try to search for contiguous block in
+ * stripe size. This should result in better allocation on RAID setups. If
+ * not, we search in the specific group using bitmap for best extents. The
+ * tunable min_to_scan and max_to_scan control the behaviour here.
+ * min_to_scan indicate how long the mballoc __must__ look for a best
+ * extent and max_to_scan indicates how long the mballoc __can__ look for a
+ * best extent in the found extents. Searching for the blocks starts with
+ * the group specified as the goal value in allocation context via
+ * ac_g_ex. Each group is first checked based on the criteria whether it
+ * can be used for allocation. ext4_mb_good_group explains how the groups are
+ * checked.
+ *
+ * Both the prealloc space are getting populated as above. So for the first
+ * request we will hit the buddy cache which will result in this prealloc
+ * space getting filled. The prealloc space is then later used for the
+ * subsequent request.
+ */
+
+/*
+ * mballoc operates on the following data:
+ *  - on-disk bitmap
+ *  - in-core buddy (actually includes buddy and bitmap)
+ *  - preallocation descriptors (PAs)
+ *
+ * there are two types of preallocations:
+ *  - inode
+ *    assiged to specific inode and can be used for this inode only.
+ *    it describes part of inode's space preallocated to specific
+ *    physical blocks. any block from that preallocated can be used
+ *    independent. the descriptor just tracks number of blocks left
+ *    unused. so, before taking some block from descriptor, one must
+ *    make sure corresponded logical block isn't allocated yet. this
+ *    also means that freeing any block within descriptor's range
+ *    must discard all preallocated blocks.
+ *  - locality group
+ *    assigned to specific locality group which does not translate to
+ *    permanent set of inodes: inode can join and leave group. space
+ *    from this type of preallocation can be used for any inode. thus
+ *    it's consumed from the beginning to the end.
+ *
+ * relation between them can be expressed as:
+ *    in-core buddy = on-disk bitmap + preallocation descriptors
+ *
+ * this mean blocks mballoc considers used are:
+ *  - allocated blocks (persistent)
+ *  - preallocated blocks (non-persistent)
+ *
+ * consistency in mballoc world means that at any time a block is either
+ * free or used in ALL structures. notice: "any time" should not be read
+ * literally -- time is discrete and delimited by locks.
+ *
+ *  to keep it simple, we don't use block numbers, instead we count number of
+ *  blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
+ *
+ * all operations can be expressed as:
+ *  - init buddy:			buddy = on-disk + PAs
+ *  - new PA:				buddy += N; PA = N
+ *  - use inode PA:			on-disk += N; PA -= N
+ *  - discard inode PA			buddy -= on-disk - PA; PA = 0
+ *  - use locality group PA		on-disk += N; PA -= N
+ *  - discard locality group PA		buddy -= PA; PA = 0
+ *  note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
+ *        is used in real operation because we can't know actual used
+ *        bits from PA, only from on-disk bitmap
+ *
+ * if we follow this strict logic, then all operations above should be atomic.
+ * given some of them can block, we'd have to use something like semaphores
+ * killing performance on high-end SMP hardware. let's try to relax it using
+ * the following knowledge:
+ *  1) if buddy is referenced, it's already initialized
+ *  2) while block is used in buddy and the buddy is referenced,
+ *     nobody can re-allocate that block
+ *  3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
+ *     bit set and PA claims same block, it's OK. IOW, one can set bit in
+ *     on-disk bitmap if buddy has same bit set or/and PA covers corresponded
+ *     block
+ *
+ * so, now we're building a concurrency table:
+ *  - init buddy vs.
+ *    - new PA
+ *      blocks for PA are allocated in the buddy, buddy must be referenced
+ *      until PA is linked to allocation group to avoid concurrent buddy init
+ *    - use inode PA
+ *      we need to make sure that either on-disk bitmap or PA has uptodate data
+ *      given (3) we care that PA-=N operation doesn't interfere with init
+ *    - discard inode PA
+ *      the simplest way would be to have buddy initialized by the discard
+ *    - use locality group PA
+ *      again PA-=N must be serialized with init
+ *    - discard locality group PA
+ *      the simplest way would be to have buddy initialized by the discard
+ *  - new PA vs.
+ *    - use inode PA
+ *      i_data_sem serializes them
+ *    - discard inode PA
+ *      discard process must wait until PA isn't used by another process
+ *    - use locality group PA
+ *      some mutex should serialize them
+ *    - discard locality group PA
+ *      discard process must wait until PA isn't used by another process
+ *  - use inode PA
+ *    - use inode PA
+ *      i_data_sem or another mutex should serializes them
+ *    - discard inode PA
+ *      discard process must wait until PA isn't used by another process
+ *    - use locality group PA
+ *      nothing wrong here -- they're different PAs covering different blocks
+ *    - discard locality group PA
+ *      discard process must wait until PA isn't used by another process
+ *
+ * now we're ready to make few consequences:
+ *  - PA is referenced and while it is no discard is possible
+ *  - PA is referenced until block isn't marked in on-disk bitmap
+ *  - PA changes only after on-disk bitmap
+ *  - discard must not compete with init. either init is done before
+ *    any discard or they're serialized somehow
+ *  - buddy init as sum of on-disk bitmap and PAs is done atomically
+ *
+ * a special case when we've used PA to emptiness. no need to modify buddy
+ * in this case, but we should care about concurrent init
+ *
+ */
+
+ /*
+ * Logic in few words:
+ *
+ *  - allocation:
+ *    load group
+ *    find blocks
+ *    mark bits in on-disk bitmap
+ *    release group
+ *
+ *  - use preallocation:
+ *    find proper PA (per-inode or group)
+ *    load group
+ *    mark bits in on-disk bitmap
+ *    release group
+ *    release PA
+ *
+ *  - free:
+ *    load group
+ *    mark bits in on-disk bitmap
+ *    release group
+ *
+ *  - discard preallocations in group:
+ *    mark PAs deleted
+ *    move them onto local list
+ *    load on-disk bitmap
+ *    load group
+ *    remove PA from object (inode or locality group)
+ *    mark free blocks in-core
+ *
+ *  - discard inode's preallocations:
+ */
+
+/*
+ * Locking rules
+ *
+ * Locks:
+ *  - bitlock on a group	(group)
+ *  - object (inode/locality)	(object)
+ *  - per-pa lock		(pa)
+ *
+ * Paths:
+ *  - new pa
+ *    object
+ *    group
+ *
+ *  - find and use pa:
+ *    pa
+ *
+ *  - release consumed pa:
+ *    pa
+ *    group
+ *    object
+ *
+ *  - generate in-core bitmap:
+ *    group
+ *        pa
+ *
+ *  - discard all for given object (inode, locality group):
+ *    object
+ *        pa
+ *    group
+ *
+ *  - discard all for given group:
+ *    group
+ *        pa
+ *    group
+ *        object
+ *
+ */
+static struct kmem_cache *ext4_pspace_cachep;
+static struct kmem_cache *ext4_ac_cachep;
+static struct kmem_cache *ext4_free_data_cachep;
+
+/* We create slab caches for groupinfo data structures based on the
+ * superblock block size.  There will be one per mounted filesystem for
+ * each unique s_blocksize_bits */
+#define NR_GRPINFO_CACHES 8
+static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
+
+static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
+	"ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
+	"ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
+	"ext4_groupinfo_64k", "ext4_groupinfo_128k"
+};
+
+static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
+					ext4_group_t group);
+static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
+						ext4_group_t group);
+static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac);
+
+/*
+ * The algorithm using this percpu seq counter goes below:
+ * 1. We sample the percpu discard_pa_seq counter before trying for block
+ *    allocation in ext4_mb_new_blocks().
+ * 2. We increment this percpu discard_pa_seq counter when we either allocate
+ *    or free these blocks i.e. while marking those blocks as used/free in
+ *    mb_mark_used()/mb_free_blocks().
+ * 3. We also increment this percpu seq counter when we successfully identify
+ *    that the bb_prealloc_list is not empty and hence proceed for discarding
+ *    of those PAs inside ext4_mb_discard_group_preallocations().
+ *
+ * Now to make sure that the regular fast path of block allocation is not
+ * affected, as a small optimization we only sample the percpu seq counter
+ * on that cpu. Only when the block allocation fails and when freed blocks
+ * found were 0, that is when we sample percpu seq counter for all cpus using
+ * below function ext4_get_discard_pa_seq_sum(). This happens after making
+ * sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty.
+ */
+static DEFINE_PER_CPU(u64, discard_pa_seq);
+static inline u64 ext4_get_discard_pa_seq_sum(void)
+{
+	int __cpu;
+	u64 __seq = 0;
+
+	for_each_possible_cpu(__cpu)
+		__seq += per_cpu(discard_pa_seq, __cpu);
+	return __seq;
+}
+
+static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
+{
+#if BITS_PER_LONG == 64
+	*bit += ((unsigned long) addr & 7UL) << 3;
+	addr = (void *) ((unsigned long) addr & ~7UL);
+#elif BITS_PER_LONG == 32
+	*bit += ((unsigned long) addr & 3UL) << 3;
+	addr = (void *) ((unsigned long) addr & ~3UL);
+#else
+#error "how many bits you are?!"
+#endif
+	return addr;
+}
+
+static inline int mb_test_bit(int bit, void *addr)
+{
+	/*
+	 * ext4_test_bit on architecture like powerpc
+	 * needs unsigned long aligned address
+	 */
+	addr = mb_correct_addr_and_bit(&bit, addr);
+	return ext4_test_bit(bit, addr);
+}
+
+static inline void mb_set_bit(int bit, void *addr)
+{
+	addr = mb_correct_addr_and_bit(&bit, addr);
+	ext4_set_bit(bit, addr);
+}
+
+static inline void mb_clear_bit(int bit, void *addr)
+{
+	addr = mb_correct_addr_and_bit(&bit, addr);
+	ext4_clear_bit(bit, addr);
+}
+
+static inline int mb_test_and_clear_bit(int bit, void *addr)
+{
+	addr = mb_correct_addr_and_bit(&bit, addr);
+	return ext4_test_and_clear_bit(bit, addr);
+}
+
+static inline int mb_find_next_zero_bit(void *addr, int max, int start)
+{
+	int fix = 0, ret, tmpmax;
+	addr = mb_correct_addr_and_bit(&fix, addr);
+	tmpmax = max + fix;
+	start += fix;
+
+	ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
+	if (ret > max)
+		return max;
+	return ret;
+}
+
+static inline int mb_find_next_bit(void *addr, int max, int start)
+{
+	int fix = 0, ret, tmpmax;
+	addr = mb_correct_addr_and_bit(&fix, addr);
+	tmpmax = max + fix;
+	start += fix;
+
+	ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
+	if (ret > max)
+		return max;
+	return ret;
+}
+
+static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
+{
+	char *bb;
+
+	BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
+	BUG_ON(max == NULL);
+
+	if (order > e4b->bd_blkbits + 1) {
+		*max = 0;
+		return NULL;
+	}
+
+	/* at order 0 we see each particular block */
+	if (order == 0) {
+		*max = 1 << (e4b->bd_blkbits + 3);
+		return e4b->bd_bitmap;
+	}
+
+	bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
+	*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
+
+	return bb;
+}
+
+#ifdef DOUBLE_CHECK
+static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
+			   int first, int count)
+{
+	int i;
+	struct super_block *sb = e4b->bd_sb;
+
+	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
+		return;
+	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
+	for (i = 0; i < count; i++) {
+		if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
+			ext4_fsblk_t blocknr;
+
+			blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
+			blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
+			ext4_grp_locked_error(sb, e4b->bd_group,
+					      inode ? inode->i_ino : 0,
+					      blocknr,
+					      "freeing block already freed "
+					      "(bit %u)",
+					      first + i);
+			ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		}
+		mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
+	}
+}
+
+static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
+{
+	int i;
+
+	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
+		return;
+	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
+	for (i = 0; i < count; i++) {
+		BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
+		mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
+	}
+}
+
+static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
+{
+	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
+		return;
+	if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
+		unsigned char *b1, *b2;
+		int i;
+		b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
+		b2 = (unsigned char *) bitmap;
+		for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
+			if (b1[i] != b2[i]) {
+				ext4_msg(e4b->bd_sb, KERN_ERR,
+					 "corruption in group %u "
+					 "at byte %u(%u): %x in copy != %x "
+					 "on disk/prealloc",
+					 e4b->bd_group, i, i * 8, b1[i], b2[i]);
+				BUG();
+			}
+		}
+	}
+}
+
+static void mb_group_bb_bitmap_alloc(struct super_block *sb,
+			struct ext4_group_info *grp, ext4_group_t group)
+{
+	struct buffer_head *bh;
+
+	grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS);
+	if (!grp->bb_bitmap)
+		return;
+
+	bh = ext4_read_block_bitmap(sb, group);
+	if (IS_ERR_OR_NULL(bh)) {
+		kfree(grp->bb_bitmap);
+		grp->bb_bitmap = NULL;
+		return;
+	}
+
+	memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize);
+	put_bh(bh);
+}
+
+static void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
+{
+	kfree(grp->bb_bitmap);
+}
+
+#else
+static inline void mb_free_blocks_double(struct inode *inode,
+				struct ext4_buddy *e4b, int first, int count)
+{
+	return;
+}
+static inline void mb_mark_used_double(struct ext4_buddy *e4b,
+						int first, int count)
+{
+	return;
+}
+static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
+{
+	return;
+}
+
+static inline void mb_group_bb_bitmap_alloc(struct super_block *sb,
+			struct ext4_group_info *grp, ext4_group_t group)
+{
+	return;
+}
+
+static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
+{
+	return;
+}
+#endif
+
+#ifdef AGGRESSIVE_CHECK
+
+#define MB_CHECK_ASSERT(assert)						\
+do {									\
+	if (!(assert)) {						\
+		printk(KERN_EMERG					\
+			"Assertion failure in %s() at %s:%d: \"%s\"\n",	\
+			function, file, line, # assert);		\
+		BUG();							\
+	}								\
+} while (0)
+
+static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
+				const char *function, int line)
+{
+	struct super_block *sb = e4b->bd_sb;
+	int order = e4b->bd_blkbits + 1;
+	int max;
+	int max2;
+	int i;
+	int j;
+	int k;
+	int count;
+	struct ext4_group_info *grp;
+	int fragments = 0;
+	int fstart;
+	struct list_head *cur;
+	void *buddy;
+	void *buddy2;
+
+	if (e4b->bd_info->bb_check_counter++ % 10)
+		return 0;
+
+	while (order > 1) {
+		buddy = mb_find_buddy(e4b, order, &max);
+		MB_CHECK_ASSERT(buddy);
+		buddy2 = mb_find_buddy(e4b, order - 1, &max2);
+		MB_CHECK_ASSERT(buddy2);
+		MB_CHECK_ASSERT(buddy != buddy2);
+		MB_CHECK_ASSERT(max * 2 == max2);
+
+		count = 0;
+		for (i = 0; i < max; i++) {
+
+			if (mb_test_bit(i, buddy)) {
+				/* only single bit in buddy2 may be 1 */
+				if (!mb_test_bit(i << 1, buddy2)) {
+					MB_CHECK_ASSERT(
+						mb_test_bit((i<<1)+1, buddy2));
+				} else if (!mb_test_bit((i << 1) + 1, buddy2)) {
+					MB_CHECK_ASSERT(
+						mb_test_bit(i << 1, buddy2));
+				}
+				continue;
+			}
+
+			/* both bits in buddy2 must be 1 */
+			MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
+			MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
+
+			for (j = 0; j < (1 << order); j++) {
+				k = (i * (1 << order)) + j;
+				MB_CHECK_ASSERT(
+					!mb_test_bit(k, e4b->bd_bitmap));
+			}
+			count++;
+		}
+		MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
+		order--;
+	}
+
+	fstart = -1;
+	buddy = mb_find_buddy(e4b, 0, &max);
+	for (i = 0; i < max; i++) {
+		if (!mb_test_bit(i, buddy)) {
+			MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
+			if (fstart == -1) {
+				fragments++;
+				fstart = i;
+			}
+			continue;
+		}
+		fstart = -1;
+		/* check used bits only */
+		for (j = 0; j < e4b->bd_blkbits + 1; j++) {
+			buddy2 = mb_find_buddy(e4b, j, &max2);
+			k = i >> j;
+			MB_CHECK_ASSERT(k < max2);
+			MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
+		}
+	}
+	MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
+	MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
+
+	grp = ext4_get_group_info(sb, e4b->bd_group);
+	if (!grp)
+		return NULL;
+	list_for_each(cur, &grp->bb_prealloc_list) {
+		ext4_group_t groupnr;
+		struct ext4_prealloc_space *pa;
+		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
+		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
+		MB_CHECK_ASSERT(groupnr == e4b->bd_group);
+		for (i = 0; i < pa->pa_len; i++)
+			MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
+	}
+	return 0;
+}
+#undef MB_CHECK_ASSERT
+#define mb_check_buddy(e4b) __mb_check_buddy(e4b,	\
+					__FILE__, __func__, __LINE__)
+#else
+#define mb_check_buddy(e4b)
+#endif
+
+/*
+ * Divide blocks started from @first with length @len into
+ * smaller chunks with power of 2 blocks.
+ * Clear the bits in bitmap which the blocks of the chunk(s) covered,
+ * then increase bb_counters[] for corresponded chunk size.
+ */
+static void ext4_mb_mark_free_simple(struct super_block *sb,
+				void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
+					struct ext4_group_info *grp)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_grpblk_t min;
+	ext4_grpblk_t max;
+	ext4_grpblk_t chunk;
+	unsigned int border;
+
+	BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
+
+	border = 2 << sb->s_blocksize_bits;
+
+	while (len > 0) {
+		/* find how many blocks can be covered since this position */
+		max = ffs(first | border) - 1;
+
+		/* find how many blocks of power 2 we need to mark */
+		min = fls(len) - 1;
+
+		if (max < min)
+			min = max;
+		chunk = 1 << min;
+
+		/* mark multiblock chunks only */
+		grp->bb_counters[min]++;
+		if (min > 0)
+			mb_clear_bit(first >> min,
+				     buddy + sbi->s_mb_offsets[min]);
+
+		len -= chunk;
+		first += chunk;
+	}
+}
+
+/*
+ * Cache the order of the largest free extent we have available in this block
+ * group.
+ */
+static void
+mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
+{
+	int i;
+	int bits;
+
+	grp->bb_largest_free_order = -1; /* uninit */
+
+	bits = sb->s_blocksize_bits + 1;
+	for (i = bits; i >= 0; i--) {
+		if (grp->bb_counters[i] > 0) {
+			grp->bb_largest_free_order = i;
+			break;
+		}
+	}
+}
+
+static noinline_for_stack
+void ext4_mb_generate_buddy(struct super_block *sb,
+			    void *buddy, void *bitmap, ext4_group_t group,
+			    struct ext4_group_info *grp)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
+	ext4_grpblk_t i = 0;
+	ext4_grpblk_t first;
+	ext4_grpblk_t len;
+	unsigned free = 0;
+	unsigned fragments = 0;
+	unsigned long long period = get_cycles();
+
+	/* initialize buddy from bitmap which is aggregation
+	 * of on-disk bitmap and preallocations */
+	i = mb_find_next_zero_bit(bitmap, max, 0);
+	grp->bb_first_free = i;
+	while (i < max) {
+		fragments++;
+		first = i;
+		i = mb_find_next_bit(bitmap, max, i);
+		len = i - first;
+		free += len;
+		if (len > 1)
+			ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
+		else
+			grp->bb_counters[0]++;
+		if (i < max)
+			i = mb_find_next_zero_bit(bitmap, max, i);
+	}
+	grp->bb_fragments = fragments;
+
+	if (free != grp->bb_free) {
+		ext4_grp_locked_error(sb, group, 0, 0,
+				      "block bitmap and bg descriptor "
+				      "inconsistent: %u vs %u free clusters",
+				      free, grp->bb_free);
+		/*
+		 * If we intend to continue, we consider group descriptor
+		 * corrupt and update bb_free using bitmap value
+		 */
+		grp->bb_free = free;
+		ext4_mark_group_bitmap_corrupted(sb, group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+	}
+	mb_set_largest_free_order(sb, grp);
+
+	clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
+
+	period = get_cycles() - period;
+	atomic_inc(&sbi->s_mb_buddies_generated);
+	atomic64_add(period, &sbi->s_mb_generation_time);
+}
+
+/* The buddy information is attached the buddy cache inode
+ * for convenience. The information regarding each group
+ * is loaded via ext4_mb_load_buddy. The information involve
+ * block bitmap and buddy information. The information are
+ * stored in the inode as
+ *
+ * {                        page                        }
+ * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
+ *
+ *
+ * one block each for bitmap and buddy information.
+ * So for each group we take up 2 blocks. A page can
+ * contain blocks_per_page (PAGE_SIZE / blocksize)  blocks.
+ * So it can have information regarding groups_per_page which
+ * is blocks_per_page/2
+ *
+ * Locking note:  This routine takes the block group lock of all groups
+ * for this page; do not hold this lock when calling this routine!
+ */
+
+static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
+{
+	ext4_group_t ngroups;
+	int blocksize;
+	int blocks_per_page;
+	int groups_per_page;
+	int err = 0;
+	int i;
+	ext4_group_t first_group, group;
+	int first_block;
+	struct super_block *sb;
+	struct buffer_head *bhs;
+	struct buffer_head **bh = NULL;
+	struct inode *inode;
+	char *data;
+	char *bitmap;
+	struct ext4_group_info *grinfo;
+
+	inode = page->mapping->host;
+	sb = inode->i_sb;
+	ngroups = ext4_get_groups_count(sb);
+	blocksize = i_blocksize(inode);
+	blocks_per_page = PAGE_SIZE / blocksize;
+
+	mb_debug(sb, "init page %lu\n", page->index);
+
+	groups_per_page = blocks_per_page >> 1;
+	if (groups_per_page == 0)
+		groups_per_page = 1;
+
+	/* allocate buffer_heads to read bitmaps */
+	if (groups_per_page > 1) {
+		i = sizeof(struct buffer_head *) * groups_per_page;
+		bh = kzalloc(i, gfp);
+		if (bh == NULL) {
+			err = -ENOMEM;
+			goto out;
+		}
+	} else
+		bh = &bhs;
+
+	first_group = page->index * blocks_per_page / 2;
+
+	/* read all groups the page covers into the cache */
+	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
+		if (group >= ngroups)
+			break;
+
+		grinfo = ext4_get_group_info(sb, group);
+		if (!grinfo)
+			continue;
+		/*
+		 * If page is uptodate then we came here after online resize
+		 * which added some new uninitialized group info structs, so
+		 * we must skip all initialized uptodate buddies on the page,
+		 * which may be currently in use by an allocating task.
+		 */
+		if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
+			bh[i] = NULL;
+			continue;
+		}
+		bh[i] = ext4_read_block_bitmap_nowait(sb, group, false);
+		if (IS_ERR(bh[i])) {
+			err = PTR_ERR(bh[i]);
+			bh[i] = NULL;
+			goto out;
+		}
+		mb_debug(sb, "read bitmap for group %u\n", group);
+	}
+
+	/* wait for I/O completion */
+	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
+		int err2;
+
+		if (!bh[i])
+			continue;
+		err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
+		if (!err)
+			err = err2;
+	}
+
+	first_block = page->index * blocks_per_page;
+	for (i = 0; i < blocks_per_page; i++) {
+		group = (first_block + i) >> 1;
+		if (group >= ngroups)
+			break;
+
+		if (!bh[group - first_group])
+			/* skip initialized uptodate buddy */
+			continue;
+
+		if (!buffer_verified(bh[group - first_group]))
+			/* Skip faulty bitmaps */
+			continue;
+		err = 0;
+
+		/*
+		 * data carry information regarding this
+		 * particular group in the format specified
+		 * above
+		 *
+		 */
+		data = page_address(page) + (i * blocksize);
+		bitmap = bh[group - first_group]->b_data;
+
+		/*
+		 * We place the buddy block and bitmap block
+		 * close together
+		 */
+		if ((first_block + i) & 1) {
+			/* this is block of buddy */
+			BUG_ON(incore == NULL);
+			mb_debug(sb, "put buddy for group %u in page %lu/%x\n",
+				group, page->index, i * blocksize);
+			trace_ext4_mb_buddy_bitmap_load(sb, group);
+			grinfo = ext4_get_group_info(sb, group);
+			if (!grinfo) {
+				err = -EFSCORRUPTED;
+				goto out;
+			}
+			grinfo->bb_fragments = 0;
+			memset(grinfo->bb_counters, 0,
+			       sizeof(*grinfo->bb_counters) *
+				(sb->s_blocksize_bits+2));
+			/*
+			 * incore got set to the group block bitmap below
+			 */
+			ext4_lock_group(sb, group);
+			/* init the buddy */
+			memset(data, 0xff, blocksize);
+			ext4_mb_generate_buddy(sb, data, incore, group, grinfo);
+			ext4_unlock_group(sb, group);
+			incore = NULL;
+		} else {
+			/* this is block of bitmap */
+			BUG_ON(incore != NULL);
+			mb_debug(sb, "put bitmap for group %u in page %lu/%x\n",
+				group, page->index, i * blocksize);
+			trace_ext4_mb_bitmap_load(sb, group);
+
+			/* see comments in ext4_mb_put_pa() */
+			ext4_lock_group(sb, group);
+			memcpy(data, bitmap, blocksize);
+
+			/* mark all preallocated blks used in in-core bitmap */
+			ext4_mb_generate_from_pa(sb, data, group);
+			ext4_mb_generate_from_freelist(sb, data, group);
+			ext4_unlock_group(sb, group);
+
+			/* set incore so that the buddy information can be
+			 * generated using this
+			 */
+			incore = data;
+		}
+	}
+	SetPageUptodate(page);
+
+out:
+	if (bh) {
+		for (i = 0; i < groups_per_page; i++)
+			brelse(bh[i]);
+		if (bh != &bhs)
+			kfree(bh);
+	}
+	return err;
+}
+
+/*
+ * Lock the buddy and bitmap pages. This make sure other parallel init_group
+ * on the same buddy page doesn't happen whild holding the buddy page lock.
+ * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
+ * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
+ */
+static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
+		ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
+{
+	struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
+	int block, pnum, poff;
+	int blocks_per_page;
+	struct page *page;
+
+	e4b->bd_buddy_page = NULL;
+	e4b->bd_bitmap_page = NULL;
+
+	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
+	/*
+	 * the buddy cache inode stores the block bitmap
+	 * and buddy information in consecutive blocks.
+	 * So for each group we need two blocks.
+	 */
+	block = group * 2;
+	pnum = block / blocks_per_page;
+	poff = block % blocks_per_page;
+	page = find_or_create_page(inode->i_mapping, pnum, gfp);
+	if (!page)
+		return -ENOMEM;
+	BUG_ON(page->mapping != inode->i_mapping);
+	e4b->bd_bitmap_page = page;
+	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
+
+	if (blocks_per_page >= 2) {
+		/* buddy and bitmap are on the same page */
+		return 0;
+	}
+
+	block++;
+	pnum = block / blocks_per_page;
+	page = find_or_create_page(inode->i_mapping, pnum, gfp);
+	if (!page)
+		return -ENOMEM;
+	BUG_ON(page->mapping != inode->i_mapping);
+	e4b->bd_buddy_page = page;
+	return 0;
+}
+
+static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
+{
+	if (e4b->bd_bitmap_page) {
+		unlock_page(e4b->bd_bitmap_page);
+		put_page(e4b->bd_bitmap_page);
+	}
+	if (e4b->bd_buddy_page) {
+		unlock_page(e4b->bd_buddy_page);
+		put_page(e4b->bd_buddy_page);
+	}
+}
+
+/*
+ * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
+ * block group lock of all groups for this page; do not hold the BG lock when
+ * calling this routine!
+ */
+static noinline_for_stack
+int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
+{
+
+	struct ext4_group_info *this_grp;
+	struct ext4_buddy e4b;
+	struct page *page;
+	int ret = 0;
+
+	might_sleep();
+	mb_debug(sb, "init group %u\n", group);
+	this_grp = ext4_get_group_info(sb, group);
+	if (!this_grp)
+		return -EFSCORRUPTED;
+
+	/*
+	 * This ensures that we don't reinit the buddy cache
+	 * page which map to the group from which we are already
+	 * allocating. If we are looking at the buddy cache we would
+	 * have taken a reference using ext4_mb_load_buddy and that
+	 * would have pinned buddy page to page cache.
+	 * The call to ext4_mb_get_buddy_page_lock will mark the
+	 * page accessed.
+	 */
+	ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
+	if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
+		/*
+		 * somebody initialized the group
+		 * return without doing anything
+		 */
+		goto err;
+	}
+
+	page = e4b.bd_bitmap_page;
+	ret = ext4_mb_init_cache(page, NULL, gfp);
+	if (ret)
+		goto err;
+	if (!PageUptodate(page)) {
+		ret = -EIO;
+		goto err;
+	}
+
+	if (e4b.bd_buddy_page == NULL) {
+		/*
+		 * If both the bitmap and buddy are in
+		 * the same page we don't need to force
+		 * init the buddy
+		 */
+		ret = 0;
+		goto err;
+	}
+	/* init buddy cache */
+	page = e4b.bd_buddy_page;
+	ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
+	if (ret)
+		goto err;
+	if (!PageUptodate(page)) {
+		ret = -EIO;
+		goto err;
+	}
+err:
+	ext4_mb_put_buddy_page_lock(&e4b);
+	return ret;
+}
+
+/*
+ * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
+ * block group lock of all groups for this page; do not hold the BG lock when
+ * calling this routine!
+ */
+static noinline_for_stack int
+ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
+		       struct ext4_buddy *e4b, gfp_t gfp)
+{
+	int blocks_per_page;
+	int block;
+	int pnum;
+	int poff;
+	struct page *page;
+	int ret;
+	struct ext4_group_info *grp;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct inode *inode = sbi->s_buddy_cache;
+
+	might_sleep();
+	mb_debug(sb, "load group %u\n", group);
+
+	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
+	grp = ext4_get_group_info(sb, group);
+	if (!grp)
+		return -EFSCORRUPTED;
+
+	e4b->bd_blkbits = sb->s_blocksize_bits;
+	e4b->bd_info = grp;
+	e4b->bd_sb = sb;
+	e4b->bd_group = group;
+	e4b->bd_buddy_page = NULL;
+	e4b->bd_bitmap_page = NULL;
+
+	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
+		/*
+		 * we need full data about the group
+		 * to make a good selection
+		 */
+		ret = ext4_mb_init_group(sb, group, gfp);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * the buddy cache inode stores the block bitmap
+	 * and buddy information in consecutive blocks.
+	 * So for each group we need two blocks.
+	 */
+	block = group * 2;
+	pnum = block / blocks_per_page;
+	poff = block % blocks_per_page;
+
+	/* we could use find_or_create_page(), but it locks page
+	 * what we'd like to avoid in fast path ... */
+	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
+	if (page == NULL || !PageUptodate(page)) {
+		if (page)
+			/*
+			 * drop the page reference and try
+			 * to get the page with lock. If we
+			 * are not uptodate that implies
+			 * somebody just created the page but
+			 * is yet to initialize the same. So
+			 * wait for it to initialize.
+			 */
+			put_page(page);
+		page = find_or_create_page(inode->i_mapping, pnum, gfp);
+		if (page) {
+			BUG_ON(page->mapping != inode->i_mapping);
+			if (!PageUptodate(page)) {
+				ret = ext4_mb_init_cache(page, NULL, gfp);
+				if (ret) {
+					unlock_page(page);
+					goto err;
+				}
+				mb_cmp_bitmaps(e4b, page_address(page) +
+					       (poff * sb->s_blocksize));
+			}
+			unlock_page(page);
+		}
+	}
+	if (page == NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+	if (!PageUptodate(page)) {
+		ret = -EIO;
+		goto err;
+	}
+
+	/* Pages marked accessed already */
+	e4b->bd_bitmap_page = page;
+	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
+
+	block++;
+	pnum = block / blocks_per_page;
+	poff = block % blocks_per_page;
+
+	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
+	if (page == NULL || !PageUptodate(page)) {
+		if (page)
+			put_page(page);
+		page = find_or_create_page(inode->i_mapping, pnum, gfp);
+		if (page) {
+			BUG_ON(page->mapping != inode->i_mapping);
+			if (!PageUptodate(page)) {
+				ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
+							 gfp);
+				if (ret) {
+					unlock_page(page);
+					goto err;
+				}
+			}
+			unlock_page(page);
+		}
+	}
+	if (page == NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+	if (!PageUptodate(page)) {
+		ret = -EIO;
+		goto err;
+	}
+
+	/* Pages marked accessed already */
+	e4b->bd_buddy_page = page;
+	e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
+
+	return 0;
+
+err:
+	if (page)
+		put_page(page);
+	if (e4b->bd_bitmap_page)
+		put_page(e4b->bd_bitmap_page);
+	if (e4b->bd_buddy_page)
+		put_page(e4b->bd_buddy_page);
+	e4b->bd_buddy = NULL;
+	e4b->bd_bitmap = NULL;
+	return ret;
+}
+
+static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
+			      struct ext4_buddy *e4b)
+{
+	return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS);
+}
+
+static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
+{
+	if (e4b->bd_bitmap_page)
+		put_page(e4b->bd_bitmap_page);
+	if (e4b->bd_buddy_page)
+		put_page(e4b->bd_buddy_page);
+}
+
+
+static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
+{
+	int order = 1;
+	int bb_incr = 1 << (e4b->bd_blkbits - 1);
+	void *bb;
+
+	BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
+	BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
+
+	bb = e4b->bd_buddy;
+	while (order <= e4b->bd_blkbits + 1) {
+		block = block >> 1;
+		if (!mb_test_bit(block, bb)) {
+			/* this block is part of buddy of order 'order' */
+			return order;
+		}
+		bb += bb_incr;
+		bb_incr >>= 1;
+		order++;
+	}
+	return 0;
+}
+
+static void mb_clear_bits(void *bm, int cur, int len)
+{
+	__u32 *addr;
+
+	len = cur + len;
+	while (cur < len) {
+		if ((cur & 31) == 0 && (len - cur) >= 32) {
+			/* fast path: clear whole word at once */
+			addr = bm + (cur >> 3);
+			*addr = 0;
+			cur += 32;
+			continue;
+		}
+		mb_clear_bit(cur, bm);
+		cur++;
+	}
+}
+
+/* clear bits in given range
+ * will return first found zero bit if any, -1 otherwise
+ */
+static int mb_test_and_clear_bits(void *bm, int cur, int len)
+{
+	__u32 *addr;
+	int zero_bit = -1;
+
+	len = cur + len;
+	while (cur < len) {
+		if ((cur & 31) == 0 && (len - cur) >= 32) {
+			/* fast path: clear whole word at once */
+			addr = bm + (cur >> 3);
+			if (*addr != (__u32)(-1) && zero_bit == -1)
+				zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
+			*addr = 0;
+			cur += 32;
+			continue;
+		}
+		if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
+			zero_bit = cur;
+		cur++;
+	}
+
+	return zero_bit;
+}
+
+void ext4_set_bits(void *bm, int cur, int len)
+{
+	__u32 *addr;
+
+	len = cur + len;
+	while (cur < len) {
+		if ((cur & 31) == 0 && (len - cur) >= 32) {
+			/* fast path: set whole word at once */
+			addr = bm + (cur >> 3);
+			*addr = 0xffffffff;
+			cur += 32;
+			continue;
+		}
+		mb_set_bit(cur, bm);
+		cur++;
+	}
+}
+
+static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
+{
+	if (mb_test_bit(*bit + side, bitmap)) {
+		mb_clear_bit(*bit, bitmap);
+		(*bit) -= side;
+		return 1;
+	}
+	else {
+		(*bit) += side;
+		mb_set_bit(*bit, bitmap);
+		return -1;
+	}
+}
+
+static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
+{
+	int max;
+	int order = 1;
+	void *buddy = mb_find_buddy(e4b, order, &max);
+
+	while (buddy) {
+		void *buddy2;
+
+		/* Bits in range [first; last] are known to be set since
+		 * corresponding blocks were allocated. Bits in range
+		 * (first; last) will stay set because they form buddies on
+		 * upper layer. We just deal with borders if they don't
+		 * align with upper layer and then go up.
+		 * Releasing entire group is all about clearing
+		 * single bit of highest order buddy.
+		 */
+
+		/* Example:
+		 * ---------------------------------
+		 * |   1   |   1   |   1   |   1   |
+		 * ---------------------------------
+		 * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
+		 * ---------------------------------
+		 *   0   1   2   3   4   5   6   7
+		 *      \_____________________/
+		 *
+		 * Neither [1] nor [6] is aligned to above layer.
+		 * Left neighbour [0] is free, so mark it busy,
+		 * decrease bb_counters and extend range to
+		 * [0; 6]
+		 * Right neighbour [7] is busy. It can't be coaleasced with [6], so
+		 * mark [6] free, increase bb_counters and shrink range to
+		 * [0; 5].
+		 * Then shift range to [0; 2], go up and do the same.
+		 */
+
+
+		if (first & 1)
+			e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
+		if (!(last & 1))
+			e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
+		if (first > last)
+			break;
+		order++;
+
+		if (first == last || !(buddy2 = mb_find_buddy(e4b, order, &max))) {
+			mb_clear_bits(buddy, first, last - first + 1);
+			e4b->bd_info->bb_counters[order - 1] += last - first + 1;
+			break;
+		}
+		first >>= 1;
+		last >>= 1;
+		buddy = buddy2;
+	}
+}
+
+static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
+			   int first, int count)
+{
+	int left_is_free = 0;
+	int right_is_free = 0;
+	int block;
+	int last = first + count - 1;
+	struct super_block *sb = e4b->bd_sb;
+
+	if (WARN_ON(count == 0))
+		return;
+	BUG_ON(last >= (sb->s_blocksize << 3));
+	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
+	/* Don't bother if the block group is corrupt. */
+	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
+		return;
+
+	mb_check_buddy(e4b);
+	mb_free_blocks_double(inode, e4b, first, count);
+
+	this_cpu_inc(discard_pa_seq);
+	e4b->bd_info->bb_free += count;
+	if (first < e4b->bd_info->bb_first_free)
+		e4b->bd_info->bb_first_free = first;
+
+	/* access memory sequentially: check left neighbour,
+	 * clear range and then check right neighbour
+	 */
+	if (first != 0)
+		left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
+	block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
+	if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
+		right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
+
+	if (unlikely(block != -1)) {
+		struct ext4_sb_info *sbi = EXT4_SB(sb);
+		ext4_fsblk_t blocknr;
+
+		blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
+		blocknr += EXT4_C2B(sbi, block);
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+			ext4_grp_locked_error(sb, e4b->bd_group,
+					      inode ? inode->i_ino : 0,
+					      blocknr,
+					      "freeing already freed block (bit %u); block bitmap corrupt.",
+					      block);
+			ext4_mark_group_bitmap_corrupted(
+				sb, e4b->bd_group,
+				EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		}
+		goto done;
+	}
+
+	/* let's maintain fragments counter */
+	if (left_is_free && right_is_free)
+		e4b->bd_info->bb_fragments--;
+	else if (!left_is_free && !right_is_free)
+		e4b->bd_info->bb_fragments++;
+
+	/* buddy[0] == bd_bitmap is a special case, so handle
+	 * it right away and let mb_buddy_mark_free stay free of
+	 * zero order checks.
+	 * Check if neighbours are to be coaleasced,
+	 * adjust bitmap bb_counters and borders appropriately.
+	 */
+	if (first & 1) {
+		first += !left_is_free;
+		e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
+	}
+	if (!(last & 1)) {
+		last -= !right_is_free;
+		e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
+	}
+
+	if (first <= last)
+		mb_buddy_mark_free(e4b, first >> 1, last >> 1);
+
+done:
+	mb_set_largest_free_order(sb, e4b->bd_info);
+	mb_check_buddy(e4b);
+}
+
+static int mb_find_extent(struct ext4_buddy *e4b, int block,
+				int needed, struct ext4_free_extent *ex)
+{
+	int next = block;
+	int max, order;
+	void *buddy;
+
+	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
+	BUG_ON(ex == NULL);
+
+	buddy = mb_find_buddy(e4b, 0, &max);
+	BUG_ON(buddy == NULL);
+	BUG_ON(block >= max);
+	if (mb_test_bit(block, buddy)) {
+		ex->fe_len = 0;
+		ex->fe_start = 0;
+		ex->fe_group = 0;
+		return 0;
+	}
+
+	/* find actual order */
+	order = mb_find_order_for_block(e4b, block);
+	block = block >> order;
+
+	ex->fe_len = 1 << order;
+	ex->fe_start = block << order;
+	ex->fe_group = e4b->bd_group;
+
+	/* calc difference from given start */
+	next = next - ex->fe_start;
+	ex->fe_len -= next;
+	ex->fe_start += next;
+
+	while (needed > ex->fe_len &&
+	       mb_find_buddy(e4b, order, &max)) {
+
+		if (block + 1 >= max)
+			break;
+
+		next = (block + 1) * (1 << order);
+		if (mb_test_bit(next, e4b->bd_bitmap))
+			break;
+
+		order = mb_find_order_for_block(e4b, next);
+
+		block = next >> order;
+		ex->fe_len += 1 << order;
+	}
+
+	if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) {
+		/* Should never happen! (but apparently sometimes does?!?) */
+		WARN_ON(1);
+		ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0,
+			"corruption or bug in mb_find_extent "
+			"block=%d, order=%d needed=%d ex=%u/%d/%d@%u",
+			block, order, needed, ex->fe_group, ex->fe_start,
+			ex->fe_len, ex->fe_logical);
+		ex->fe_len = 0;
+		ex->fe_start = 0;
+		ex->fe_group = 0;
+	}
+	return ex->fe_len;
+}
+
+static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
+{
+	int ord;
+	int mlen = 0;
+	int max = 0;
+	int cur;
+	int start = ex->fe_start;
+	int len = ex->fe_len;
+	unsigned ret = 0;
+	int len0 = len;
+	void *buddy;
+
+	BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
+	BUG_ON(e4b->bd_group != ex->fe_group);
+	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
+	mb_check_buddy(e4b);
+	mb_mark_used_double(e4b, start, len);
+
+	this_cpu_inc(discard_pa_seq);
+	e4b->bd_info->bb_free -= len;
+	if (e4b->bd_info->bb_first_free == start)
+		e4b->bd_info->bb_first_free += len;
+
+	/* let's maintain fragments counter */
+	if (start != 0)
+		mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
+	if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
+		max = !mb_test_bit(start + len, e4b->bd_bitmap);
+	if (mlen && max)
+		e4b->bd_info->bb_fragments++;
+	else if (!mlen && !max)
+		e4b->bd_info->bb_fragments--;
+
+	/* let's maintain buddy itself */
+	while (len) {
+		ord = mb_find_order_for_block(e4b, start);
+
+		if (((start >> ord) << ord) == start && len >= (1 << ord)) {
+			/* the whole chunk may be allocated at once! */
+			mlen = 1 << ord;
+			buddy = mb_find_buddy(e4b, ord, &max);
+			BUG_ON((start >> ord) >= max);
+			mb_set_bit(start >> ord, buddy);
+			e4b->bd_info->bb_counters[ord]--;
+			start += mlen;
+			len -= mlen;
+			BUG_ON(len < 0);
+			continue;
+		}
+
+		/* store for history */
+		if (ret == 0)
+			ret = len | (ord << 16);
+
+		/* we have to split large buddy */
+		BUG_ON(ord <= 0);
+		buddy = mb_find_buddy(e4b, ord, &max);
+		mb_set_bit(start >> ord, buddy);
+		e4b->bd_info->bb_counters[ord]--;
+
+		ord--;
+		cur = (start >> ord) & ~1U;
+		buddy = mb_find_buddy(e4b, ord, &max);
+		mb_clear_bit(cur, buddy);
+		mb_clear_bit(cur + 1, buddy);
+		e4b->bd_info->bb_counters[ord]++;
+		e4b->bd_info->bb_counters[ord]++;
+	}
+	mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
+
+	ext4_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
+	mb_check_buddy(e4b);
+
+	return ret;
+}
+
+/*
+ * Must be called under group lock!
+ */
+static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
+					struct ext4_buddy *e4b)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	int ret;
+
+	BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
+	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
+
+	ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
+	ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
+	ret = mb_mark_used(e4b, &ac->ac_b_ex);
+
+	/* preallocation can change ac_b_ex, thus we store actually
+	 * allocated blocks for history */
+	ac->ac_f_ex = ac->ac_b_ex;
+
+	ac->ac_status = AC_STATUS_FOUND;
+	ac->ac_tail = ret & 0xffff;
+	ac->ac_buddy = ret >> 16;
+
+	/*
+	 * take the page reference. We want the page to be pinned
+	 * so that we don't get a ext4_mb_init_cache_call for this
+	 * group until we update the bitmap. That would mean we
+	 * double allocate blocks. The reference is dropped
+	 * in ext4_mb_release_context
+	 */
+	ac->ac_bitmap_page = e4b->bd_bitmap_page;
+	get_page(ac->ac_bitmap_page);
+	ac->ac_buddy_page = e4b->bd_buddy_page;
+	get_page(ac->ac_buddy_page);
+	/* store last allocated for subsequent stream allocation */
+	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
+		spin_lock(&sbi->s_md_lock);
+		sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
+		sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
+		spin_unlock(&sbi->s_md_lock);
+	}
+	/*
+	 * As we've just preallocated more space than
+	 * user requested originally, we store allocated
+	 * space in a special descriptor.
+	 */
+	if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
+		ext4_mb_new_preallocation(ac);
+
+}
+
+static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
+					struct ext4_buddy *e4b,
+					int finish_group)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	struct ext4_free_extent *bex = &ac->ac_b_ex;
+	struct ext4_free_extent *gex = &ac->ac_g_ex;
+	struct ext4_free_extent ex;
+	int max;
+
+	if (ac->ac_status == AC_STATUS_FOUND)
+		return;
+	/*
+	 * We don't want to scan for a whole year
+	 */
+	if (ac->ac_found > sbi->s_mb_max_to_scan &&
+			!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
+		ac->ac_status = AC_STATUS_BREAK;
+		return;
+	}
+
+	/*
+	 * Haven't found good chunk so far, let's continue
+	 */
+	if (bex->fe_len < gex->fe_len)
+		return;
+
+	if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
+			&& bex->fe_group == e4b->bd_group) {
+		/* recheck chunk's availability - we don't know
+		 * when it was found (within this lock-unlock
+		 * period or not) */
+		max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
+		if (max >= gex->fe_len) {
+			ext4_mb_use_best_found(ac, e4b);
+			return;
+		}
+	}
+}
+
+/*
+ * The routine checks whether found extent is good enough. If it is,
+ * then the extent gets marked used and flag is set to the context
+ * to stop scanning. Otherwise, the extent is compared with the
+ * previous found extent and if new one is better, then it's stored
+ * in the context. Later, the best found extent will be used, if
+ * mballoc can't find good enough extent.
+ *
+ * FIXME: real allocation policy is to be designed yet!
+ */
+static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
+					struct ext4_free_extent *ex,
+					struct ext4_buddy *e4b)
+{
+	struct ext4_free_extent *bex = &ac->ac_b_ex;
+	struct ext4_free_extent *gex = &ac->ac_g_ex;
+
+	BUG_ON(ex->fe_len <= 0);
+	BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
+	BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
+	BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
+
+	ac->ac_found++;
+
+	/*
+	 * The special case - take what you catch first
+	 */
+	if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
+		*bex = *ex;
+		ext4_mb_use_best_found(ac, e4b);
+		return;
+	}
+
+	/*
+	 * Let's check whether the chuck is good enough
+	 */
+	if (ex->fe_len == gex->fe_len) {
+		*bex = *ex;
+		ext4_mb_use_best_found(ac, e4b);
+		return;
+	}
+
+	/*
+	 * If this is first found extent, just store it in the context
+	 */
+	if (bex->fe_len == 0) {
+		*bex = *ex;
+		return;
+	}
+
+	/*
+	 * If new found extent is better, store it in the context
+	 */
+	if (bex->fe_len < gex->fe_len) {
+		/* if the request isn't satisfied, any found extent
+		 * larger than previous best one is better */
+		if (ex->fe_len > bex->fe_len)
+			*bex = *ex;
+	} else if (ex->fe_len > gex->fe_len) {
+		/* if the request is satisfied, then we try to find
+		 * an extent that still satisfy the request, but is
+		 * smaller than previous one */
+		if (ex->fe_len < bex->fe_len)
+			*bex = *ex;
+	}
+
+	ext4_mb_check_limits(ac, e4b, 0);
+}
+
+static noinline_for_stack
+int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
+					struct ext4_buddy *e4b)
+{
+	struct ext4_free_extent ex = ac->ac_b_ex;
+	ext4_group_t group = ex.fe_group;
+	int max;
+	int err;
+
+	BUG_ON(ex.fe_len <= 0);
+	err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
+	if (err)
+		return err;
+
+	ext4_lock_group(ac->ac_sb, group);
+	max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
+
+	if (max > 0) {
+		ac->ac_b_ex = ex;
+		ext4_mb_use_best_found(ac, e4b);
+	}
+
+	ext4_unlock_group(ac->ac_sb, group);
+	ext4_mb_unload_buddy(e4b);
+
+	return 0;
+}
+
+static noinline_for_stack
+int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
+				struct ext4_buddy *e4b)
+{
+	ext4_group_t group = ac->ac_g_ex.fe_group;
+	int max;
+	int err;
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
+	struct ext4_free_extent ex;
+
+	if (!grp)
+		return -EFSCORRUPTED;
+	if (!(ac->ac_flags & (EXT4_MB_HINT_TRY_GOAL | EXT4_MB_HINT_GOAL_ONLY)))
+		return 0;
+	if (grp->bb_free == 0)
+		return 0;
+
+	err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
+	if (err)
+		return err;
+
+	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
+		ext4_mb_unload_buddy(e4b);
+		return 0;
+	}
+
+	ext4_lock_group(ac->ac_sb, group);
+	max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
+			     ac->ac_g_ex.fe_len, &ex);
+	ex.fe_logical = 0xDEADFA11; /* debug value */
+
+	if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
+		ext4_fsblk_t start;
+
+		start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
+			ex.fe_start;
+		/* use do_div to get remainder (would be 64-bit modulo) */
+		if (do_div(start, sbi->s_stripe) == 0) {
+			ac->ac_found++;
+			ac->ac_b_ex = ex;
+			ext4_mb_use_best_found(ac, e4b);
+		}
+	} else if (max >= ac->ac_g_ex.fe_len) {
+		BUG_ON(ex.fe_len <= 0);
+		BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
+		BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
+		ac->ac_found++;
+		ac->ac_b_ex = ex;
+		ext4_mb_use_best_found(ac, e4b);
+	} else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
+		/* Sometimes, caller may want to merge even small
+		 * number of blocks to an existing extent */
+		BUG_ON(ex.fe_len <= 0);
+		BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
+		BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
+		ac->ac_found++;
+		ac->ac_b_ex = ex;
+		ext4_mb_use_best_found(ac, e4b);
+	}
+	ext4_unlock_group(ac->ac_sb, group);
+	ext4_mb_unload_buddy(e4b);
+
+	return 0;
+}
+
+/*
+ * The routine scans buddy structures (not bitmap!) from given order
+ * to max order and tries to find big enough chunk to satisfy the req
+ */
+static noinline_for_stack
+void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
+					struct ext4_buddy *e4b)
+{
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_group_info *grp = e4b->bd_info;
+	void *buddy;
+	int i;
+	int k;
+	int max;
+
+	BUG_ON(ac->ac_2order <= 0);
+	for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
+		if (grp->bb_counters[i] == 0)
+			continue;
+
+		buddy = mb_find_buddy(e4b, i, &max);
+		BUG_ON(buddy == NULL);
+
+		k = mb_find_next_zero_bit(buddy, max, 0);
+		if (k >= max) {
+			ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0,
+				"%d free clusters of order %d. But found 0",
+				grp->bb_counters[i], i);
+			ext4_mark_group_bitmap_corrupted(ac->ac_sb,
+					 e4b->bd_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+			break;
+		}
+		ac->ac_found++;
+
+		ac->ac_b_ex.fe_len = 1 << i;
+		ac->ac_b_ex.fe_start = k << i;
+		ac->ac_b_ex.fe_group = e4b->bd_group;
+
+		ext4_mb_use_best_found(ac, e4b);
+
+		BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len);
+
+		if (EXT4_SB(sb)->s_mb_stats)
+			atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
+
+		break;
+	}
+}
+
+/*
+ * The routine scans the group and measures all found extents.
+ * In order to optimize scanning, caller must pass number of
+ * free blocks in the group, so the routine can know upper limit.
+ */
+static noinline_for_stack
+void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
+					struct ext4_buddy *e4b)
+{
+	struct super_block *sb = ac->ac_sb;
+	void *bitmap = e4b->bd_bitmap;
+	struct ext4_free_extent ex;
+	int i;
+	int free;
+
+	free = e4b->bd_info->bb_free;
+	if (WARN_ON(free <= 0))
+		return;
+
+	i = e4b->bd_info->bb_first_free;
+
+	while (free && ac->ac_status == AC_STATUS_CONTINUE) {
+		i = mb_find_next_zero_bit(bitmap,
+						EXT4_CLUSTERS_PER_GROUP(sb), i);
+		if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
+			/*
+			 * IF we have corrupt bitmap, we won't find any
+			 * free blocks even though group info says we
+			 * have free blocks
+			 */
+			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
+					"%d free clusters as per "
+					"group info. But bitmap says 0",
+					free);
+			ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+			break;
+		}
+
+		mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
+		if (WARN_ON(ex.fe_len <= 0))
+			break;
+		if (free < ex.fe_len) {
+			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
+					"%d free clusters as per "
+					"group info. But got %d blocks",
+					free, ex.fe_len);
+			ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+			/*
+			 * The number of free blocks differs. This mostly
+			 * indicate that the bitmap is corrupt. So exit
+			 * without claiming the space.
+			 */
+			break;
+		}
+		ex.fe_logical = 0xDEADC0DE; /* debug value */
+		ext4_mb_measure_extent(ac, &ex, e4b);
+
+		i += ex.fe_len;
+		free -= ex.fe_len;
+	}
+
+	ext4_mb_check_limits(ac, e4b, 1);
+}
+
+/*
+ * This is a special case for storages like raid5
+ * we try to find stripe-aligned chunks for stripe-size-multiple requests
+ */
+static noinline_for_stack
+void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
+				 struct ext4_buddy *e4b)
+{
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	void *bitmap = e4b->bd_bitmap;
+	struct ext4_free_extent ex;
+	ext4_fsblk_t first_group_block;
+	ext4_fsblk_t a;
+	ext4_grpblk_t i;
+	int max;
+
+	BUG_ON(sbi->s_stripe == 0);
+
+	/* find first stripe-aligned block in group */
+	first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
+
+	a = first_group_block + sbi->s_stripe - 1;
+	do_div(a, sbi->s_stripe);
+	i = (a * sbi->s_stripe) - first_group_block;
+
+	while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
+		if (!mb_test_bit(i, bitmap)) {
+			max = mb_find_extent(e4b, i, sbi->s_stripe, &ex);
+			if (max >= sbi->s_stripe) {
+				ac->ac_found++;
+				ex.fe_logical = 0xDEADF00D; /* debug value */
+				ac->ac_b_ex = ex;
+				ext4_mb_use_best_found(ac, e4b);
+				break;
+			}
+		}
+		i += sbi->s_stripe;
+	}
+}
+
+/*
+ * This is also called BEFORE we load the buddy bitmap.
+ * Returns either 1 or 0 indicating that the group is either suitable
+ * for the allocation or not.
+ */
+static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
+				ext4_group_t group, int cr)
+{
+	ext4_grpblk_t free, fragments;
+	int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
+	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
+
+	BUG_ON(cr < 0 || cr >= 4);
+
+	if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
+		return false;
+
+	free = grp->bb_free;
+	if (free == 0)
+		return false;
+
+	fragments = grp->bb_fragments;
+	if (fragments == 0)
+		return false;
+
+	switch (cr) {
+	case 0:
+		BUG_ON(ac->ac_2order == 0);
+
+		/* Avoid using the first bg of a flexgroup for data files */
+		if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
+		    (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
+		    ((group % flex_size) == 0))
+			return false;
+
+		if (free < ac->ac_g_ex.fe_len)
+			return false;
+
+		if (ac->ac_2order > ac->ac_sb->s_blocksize_bits+1)
+			return true;
+
+		if (grp->bb_largest_free_order < ac->ac_2order)
+			return false;
+
+		return true;
+	case 1:
+		if ((free / fragments) >= ac->ac_g_ex.fe_len)
+			return true;
+		break;
+	case 2:
+		if (free >= ac->ac_g_ex.fe_len)
+			return true;
+		break;
+	case 3:
+		return true;
+	default:
+		BUG();
+	}
+
+	return false;
+}
+
+/*
+ * This could return negative error code if something goes wrong
+ * during ext4_mb_init_group(). This should not be called with
+ * ext4_lock_group() held.
+ */
+static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
+				     ext4_group_t group, int cr)
+{
+	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK;
+	ext4_grpblk_t free;
+	int ret = 0;
+
+	if (!grp)
+		return -EFSCORRUPTED;
+	if (sbi->s_mb_stats)
+		atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]);
+	if (should_lock)
+		ext4_lock_group(sb, group);
+	free = grp->bb_free;
+	if (free == 0)
+		goto out;
+	if (cr <= 2 && free < ac->ac_g_ex.fe_len)
+		goto out;
+	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
+		goto out;
+	if (should_lock)
+		ext4_unlock_group(sb, group);
+
+	/* We only do this if the grp has never been initialized */
+	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
+		struct ext4_group_desc *gdp =
+			ext4_get_group_desc(sb, group, NULL);
+		int ret;
+
+		/* cr=0/1 is a very optimistic search to find large
+		 * good chunks almost for free.  If buddy data is not
+		 * ready, then this optimization makes no sense.  But
+		 * we never skip the first block group in a flex_bg,
+		 * since this gets used for metadata block allocation,
+		 * and we want to make sure we locate metadata blocks
+		 * in the first block group in the flex_bg if possible.
+		 */
+		if (cr < 2 &&
+		    (!sbi->s_log_groups_per_flex ||
+		     ((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) &&
+		    !(ext4_has_group_desc_csum(sb) &&
+		      (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))))
+			return 0;
+		ret = ext4_mb_init_group(sb, group, GFP_NOFS);
+		if (ret)
+			return ret;
+	}
+
+	if (should_lock)
+		ext4_lock_group(sb, group);
+	ret = ext4_mb_good_group(ac, group, cr);
+out:
+	if (should_lock)
+		ext4_unlock_group(sb, group);
+	return ret;
+}
+
+/*
+ * Start prefetching @nr block bitmaps starting at @group.
+ * Return the next group which needs to be prefetched.
+ */
+ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group,
+			      unsigned int nr, int *cnt)
+{
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	struct buffer_head *bh;
+	struct blk_plug plug;
+
+	blk_start_plug(&plug);
+	while (nr-- > 0) {
+		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
+								  NULL);
+		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+
+		/*
+		 * Prefetch block groups with free blocks; but don't
+		 * bother if it is marked uninitialized on disk, since
+		 * it won't require I/O to read.  Also only try to
+		 * prefetch once, so we avoid getblk() call, which can
+		 * be expensive.
+		 */
+		if (gdp && grp && !EXT4_MB_GRP_TEST_AND_SET_READ(grp) &&
+		    EXT4_MB_GRP_NEED_INIT(grp) &&
+		    ext4_free_group_clusters(sb, gdp) > 0 &&
+		    !(ext4_has_group_desc_csum(sb) &&
+		      (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) {
+			bh = ext4_read_block_bitmap_nowait(sb, group, true);
+			if (bh && !IS_ERR(bh)) {
+				if (!buffer_uptodate(bh) && cnt)
+					(*cnt)++;
+				brelse(bh);
+			}
+		}
+		if (++group >= ngroups)
+			group = 0;
+	}
+	blk_finish_plug(&plug);
+	return group;
+}
+
+/*
+ * Prefetching reads the block bitmap into the buffer cache; but we
+ * need to make sure that the buddy bitmap in the page cache has been
+ * initialized.  Note that ext4_mb_init_group() will block if the I/O
+ * is not yet completed, or indeed if it was not initiated by
+ * ext4_mb_prefetch did not start the I/O.
+ *
+ * TODO: We should actually kick off the buddy bitmap setup in a work
+ * queue when the buffer I/O is completed, so that we don't block
+ * waiting for the block allocation bitmap read to finish when
+ * ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator().
+ */
+void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
+			   unsigned int nr)
+{
+	while (nr-- > 0) {
+		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
+								  NULL);
+		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+
+		if (!group)
+			group = ext4_get_groups_count(sb);
+		group--;
+		grp = ext4_get_group_info(sb, group);
+
+		if (grp && gdp && EXT4_MB_GRP_NEED_INIT(grp) &&
+		    ext4_free_group_clusters(sb, gdp) > 0 &&
+		    !(ext4_has_group_desc_csum(sb) &&
+		      (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) {
+			if (ext4_mb_init_group(sb, group, GFP_NOFS))
+				break;
+		}
+	}
+}
+
+static noinline_for_stack int
+ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
+{
+	ext4_group_t prefetch_grp = 0, ngroups, group, i;
+	int cr = -1;
+	int err = 0, first_err = 0;
+	unsigned int nr = 0, prefetch_ios = 0;
+	struct ext4_sb_info *sbi;
+	struct super_block *sb;
+	struct ext4_buddy e4b;
+	int lost;
+
+	sb = ac->ac_sb;
+	sbi = EXT4_SB(sb);
+	ngroups = ext4_get_groups_count(sb);
+	/* non-extent files are limited to low blocks/groups */
+	if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
+		ngroups = sbi->s_blockfile_groups;
+
+	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
+
+	/* first, try the goal */
+	err = ext4_mb_find_by_goal(ac, &e4b);
+	if (err || ac->ac_status == AC_STATUS_FOUND)
+		goto out;
+
+	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
+		goto out;
+
+	/*
+	 * ac->ac_2order is set only if the fe_len is a power of 2
+	 * if ac->ac_2order is set we also set criteria to 0 so that we
+	 * try exact allocation using buddy.
+	 */
+	i = fls(ac->ac_g_ex.fe_len);
+	ac->ac_2order = 0;
+	/*
+	 * We search using buddy data only if the order of the request
+	 * is greater than equal to the sbi_s_mb_order2_reqs
+	 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
+	 * We also support searching for power-of-two requests only for
+	 * requests upto maximum buddy size we have constructed.
+	 */
+	if (i >= sbi->s_mb_order2_reqs && i <= sb->s_blocksize_bits + 2) {
+		/*
+		 * This should tell if fe_len is exactly power of 2
+		 */
+		if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
+			ac->ac_2order = array_index_nospec(i - 1,
+							   sb->s_blocksize_bits + 2);
+	}
+
+	/* if stream allocation is enabled, use global goal */
+	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
+		/* TBD: may be hot point */
+		spin_lock(&sbi->s_md_lock);
+		ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
+		ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
+		spin_unlock(&sbi->s_md_lock);
+	}
+
+	/* Let's just scan groups to find more-less suitable blocks */
+	cr = ac->ac_2order ? 0 : 1;
+	/*
+	 * cr == 0 try to get exact allocation,
+	 * cr == 3  try to get anything
+	 */
+repeat:
+	for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
+		ac->ac_criteria = cr;
+		/*
+		 * searching for the right group start
+		 * from the goal value specified
+		 */
+		group = ac->ac_g_ex.fe_group;
+		prefetch_grp = group;
+
+		for (i = 0; i < ngroups; group++, i++) {
+			int ret = 0;
+			cond_resched();
+			/*
+			 * Artificially restricted ngroups for non-extent
+			 * files makes group > ngroups possible on first loop.
+			 */
+			if (group >= ngroups)
+				group = 0;
+
+			/*
+			 * Batch reads of the block allocation bitmaps
+			 * to get multiple READs in flight; limit
+			 * prefetching at cr=0/1, otherwise mballoc can
+			 * spend a lot of time loading imperfect groups
+			 */
+			if ((prefetch_grp == group) &&
+			    (cr > 1 ||
+			     prefetch_ios < sbi->s_mb_prefetch_limit)) {
+				unsigned int curr_ios = prefetch_ios;
+
+				nr = sbi->s_mb_prefetch;
+				if (ext4_has_feature_flex_bg(sb)) {
+					nr = 1 << sbi->s_log_groups_per_flex;
+					nr -= group & (nr - 1);
+					nr = min(nr, sbi->s_mb_prefetch);
+				}
+				prefetch_grp = ext4_mb_prefetch(sb, group,
+							nr, &prefetch_ios);
+				if (prefetch_ios == curr_ios)
+					nr = 0;
+			}
+
+			/* This now checks without needing the buddy page */
+			ret = ext4_mb_good_group_nolock(ac, group, cr);
+			if (ret <= 0) {
+				if (!first_err)
+					first_err = ret;
+				continue;
+			}
+
+			err = ext4_mb_load_buddy(sb, group, &e4b);
+			if (err)
+				goto out;
+
+			ext4_lock_group(sb, group);
+
+			/*
+			 * We need to check again after locking the
+			 * block group
+			 */
+			ret = ext4_mb_good_group(ac, group, cr);
+			if (ret == 0) {
+				ext4_unlock_group(sb, group);
+				ext4_mb_unload_buddy(&e4b);
+				continue;
+			}
+
+			ac->ac_groups_scanned++;
+			if (cr == 0)
+				ext4_mb_simple_scan_group(ac, &e4b);
+			else if (cr == 1 && sbi->s_stripe &&
+					!(ac->ac_g_ex.fe_len % sbi->s_stripe))
+				ext4_mb_scan_aligned(ac, &e4b);
+			else
+				ext4_mb_complex_scan_group(ac, &e4b);
+
+			ext4_unlock_group(sb, group);
+			ext4_mb_unload_buddy(&e4b);
+
+			if (ac->ac_status != AC_STATUS_CONTINUE)
+				break;
+		}
+		/* Processed all groups and haven't found blocks */
+		if (sbi->s_mb_stats && i == ngroups)
+			atomic64_inc(&sbi->s_bal_cX_failed[cr]);
+	}
+
+	if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
+	    !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
+		/*
+		 * We've been searching too long. Let's try to allocate
+		 * the best chunk we've found so far
+		 */
+		ext4_mb_try_best_found(ac, &e4b);
+		if (ac->ac_status != AC_STATUS_FOUND) {
+			/*
+			 * Someone more lucky has already allocated it.
+			 * The only thing we can do is just take first
+			 * found block(s)
+			 */
+			lost = atomic_inc_return(&sbi->s_mb_lost_chunks);
+			mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n",
+				 ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start,
+				 ac->ac_b_ex.fe_len, lost);
+
+			ac->ac_b_ex.fe_group = 0;
+			ac->ac_b_ex.fe_start = 0;
+			ac->ac_b_ex.fe_len = 0;
+			ac->ac_status = AC_STATUS_CONTINUE;
+			ac->ac_flags |= EXT4_MB_HINT_FIRST;
+			cr = 3;
+			goto repeat;
+		}
+	}
+
+	if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND)
+		atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]);
+out:
+	if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
+		err = first_err;
+
+	mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n",
+		 ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status,
+		 ac->ac_flags, cr, err);
+
+	if (nr)
+		ext4_mb_prefetch_fini(sb, prefetch_grp, nr);
+
+	return err;
+}
+
+static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
+{
+	struct super_block *sb = PDE_DATA(file_inode(seq->file));
+	ext4_group_t group;
+
+	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
+		return NULL;
+	group = *pos + 1;
+	return (void *) ((unsigned long) group);
+}
+
+static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct super_block *sb = PDE_DATA(file_inode(seq->file));
+	ext4_group_t group;
+
+	++*pos;
+	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
+		return NULL;
+	group = *pos + 1;
+	return (void *) ((unsigned long) group);
+}
+
+static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
+{
+	struct super_block *sb = PDE_DATA(file_inode(seq->file));
+	ext4_group_t group = (ext4_group_t) ((unsigned long) v);
+	int i;
+	int err, buddy_loaded = 0;
+	struct ext4_buddy e4b;
+	struct ext4_group_info *grinfo;
+	unsigned char blocksize_bits = min_t(unsigned char,
+					     sb->s_blocksize_bits,
+					     EXT4_MAX_BLOCK_LOG_SIZE);
+	struct sg {
+		struct ext4_group_info info;
+		ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2];
+	} sg;
+
+	group--;
+	if (group == 0)
+		seq_puts(seq, "#group: free  frags first ["
+			      " 2^0   2^1   2^2   2^3   2^4   2^5   2^6  "
+			      " 2^7   2^8   2^9   2^10  2^11  2^12  2^13  ]\n");
+
+	i = (blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
+		sizeof(struct ext4_group_info);
+
+	grinfo = ext4_get_group_info(sb, group);
+	if (!grinfo)
+		return 0;
+	/* Load the group info in memory only if not already loaded. */
+	if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
+		err = ext4_mb_load_buddy(sb, group, &e4b);
+		if (err) {
+			seq_printf(seq, "#%-5u: I/O error\n", group);
+			return 0;
+		}
+		buddy_loaded = 1;
+	}
+
+	memcpy(&sg, grinfo, i);
+
+	if (buddy_loaded)
+		ext4_mb_unload_buddy(&e4b);
+
+	seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
+			sg.info.bb_fragments, sg.info.bb_first_free);
+	for (i = 0; i <= 13; i++)
+		seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ?
+				sg.info.bb_counters[i] : 0);
+	seq_puts(seq, " ]\n");
+
+	return 0;
+}
+
+static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
+{
+}
+
+const struct seq_operations ext4_mb_seq_groups_ops = {
+	.start  = ext4_mb_seq_groups_start,
+	.next   = ext4_mb_seq_groups_next,
+	.stop   = ext4_mb_seq_groups_stop,
+	.show   = ext4_mb_seq_groups_show,
+};
+
+int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset)
+{
+	struct super_block *sb = (struct super_block *)seq->private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	seq_puts(seq, "mballoc:\n");
+	if (!sbi->s_mb_stats) {
+		seq_puts(seq, "\tmb stats collection turned off.\n");
+		seq_puts(seq, "\tTo enable, please write \"1\" to sysfs file mb_stats.\n");
+		return 0;
+	}
+	seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs));
+	seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success));
+
+	seq_printf(seq, "\tgroups_scanned: %u\n",  atomic_read(&sbi->s_bal_groups_scanned));
+
+	seq_puts(seq, "\tcr0_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[0]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[0]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[0]));
+
+	seq_puts(seq, "\tcr1_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[1]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[1]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[1]));
+
+	seq_puts(seq, "\tcr2_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[2]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[2]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[2]));
+
+	seq_puts(seq, "\tcr3_stats:\n");
+	seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[3]));
+	seq_printf(seq, "\t\tgroups_considered: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_groups_considered[3]));
+	seq_printf(seq, "\t\tuseless_loops: %llu\n",
+		   atomic64_read(&sbi->s_bal_cX_failed[3]));
+	seq_printf(seq, "\textents_scanned: %u\n", atomic_read(&sbi->s_bal_ex_scanned));
+	seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals));
+	seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders));
+	seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks));
+	seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks));
+
+	seq_printf(seq, "\tbuddies_generated: %u/%u\n",
+		   atomic_read(&sbi->s_mb_buddies_generated),
+		   ext4_get_groups_count(sb));
+	seq_printf(seq, "\tbuddies_time_used: %llu\n",
+		   atomic64_read(&sbi->s_mb_generation_time));
+	seq_printf(seq, "\tpreallocated: %u\n",
+		   atomic_read(&sbi->s_mb_preallocated));
+	seq_printf(seq, "\tdiscarded: %u\n",
+		   atomic_read(&sbi->s_mb_discarded));
+	return 0;
+}
+
+static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
+{
+	int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
+	struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
+
+	BUG_ON(!cachep);
+	return cachep;
+}
+
+/*
+ * Allocate the top-level s_group_info array for the specified number
+ * of groups
+ */
+int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	unsigned size;
+	struct ext4_group_info ***old_groupinfo, ***new_groupinfo;
+
+	size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
+		EXT4_DESC_PER_BLOCK_BITS(sb);
+	if (size <= sbi->s_group_info_size)
+		return 0;
+
+	size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
+	new_groupinfo = kvzalloc(size, GFP_KERNEL);
+	if (!new_groupinfo) {
+		ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
+		return -ENOMEM;
+	}
+	rcu_read_lock();
+	old_groupinfo = rcu_dereference(sbi->s_group_info);
+	if (old_groupinfo)
+		memcpy(new_groupinfo, old_groupinfo,
+		       sbi->s_group_info_size * sizeof(*sbi->s_group_info));
+	rcu_read_unlock();
+	rcu_assign_pointer(sbi->s_group_info, new_groupinfo);
+	sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
+	if (old_groupinfo)
+		ext4_kvfree_array_rcu(old_groupinfo);
+	ext4_debug("allocated s_groupinfo array for %d meta_bg's\n", 
+		   sbi->s_group_info_size);
+	return 0;
+}
+
+/* Create and initialize ext4_group_info data for the given group. */
+int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
+			  struct ext4_group_desc *desc)
+{
+	int i;
+	int metalen = 0;
+	int idx = group >> EXT4_DESC_PER_BLOCK_BITS(sb);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_info **meta_group_info;
+	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
+
+	/*
+	 * First check if this group is the first of a reserved block.
+	 * If it's true, we have to allocate a new table of pointers
+	 * to ext4_group_info structures
+	 */
+	if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
+		metalen = sizeof(*meta_group_info) <<
+			EXT4_DESC_PER_BLOCK_BITS(sb);
+		meta_group_info = kmalloc(metalen, GFP_NOFS);
+		if (meta_group_info == NULL) {
+			ext4_msg(sb, KERN_ERR, "can't allocate mem "
+				 "for a buddy group");
+			goto exit_meta_group_info;
+		}
+		rcu_read_lock();
+		rcu_dereference(sbi->s_group_info)[idx] = meta_group_info;
+		rcu_read_unlock();
+	}
+
+	meta_group_info = sbi_array_rcu_deref(sbi, s_group_info, idx);
+	i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
+
+	meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
+	if (meta_group_info[i] == NULL) {
+		ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
+		goto exit_group_info;
+	}
+	set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
+		&(meta_group_info[i]->bb_state));
+
+	/*
+	 * initialize bb_free to be able to skip
+	 * empty groups without initialization
+	 */
+	if (ext4_has_group_desc_csum(sb) &&
+	    (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+		meta_group_info[i]->bb_free =
+			ext4_free_clusters_after_init(sb, group, desc);
+	} else {
+		meta_group_info[i]->bb_free =
+			ext4_free_group_clusters(sb, desc);
+	}
+
+	INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
+	init_rwsem(&meta_group_info[i]->alloc_sem);
+	meta_group_info[i]->bb_free_root = RB_ROOT;
+	meta_group_info[i]->bb_largest_free_order = -1;  /* uninit */
+
+	mb_group_bb_bitmap_alloc(sb, meta_group_info[i], group);
+	return 0;
+
+exit_group_info:
+	/* If a meta_group_info table has been allocated, release it now */
+	if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
+		struct ext4_group_info ***group_info;
+
+		rcu_read_lock();
+		group_info = rcu_dereference(sbi->s_group_info);
+		kfree(group_info[idx]);
+		group_info[idx] = NULL;
+		rcu_read_unlock();
+	}
+exit_meta_group_info:
+	return -ENOMEM;
+} /* ext4_mb_add_groupinfo */
+
+static int ext4_mb_init_backend(struct super_block *sb)
+{
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	ext4_group_t i;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int err;
+	struct ext4_group_desc *desc;
+	struct ext4_group_info ***group_info;
+	struct kmem_cache *cachep;
+
+	err = ext4_mb_alloc_groupinfo(sb, ngroups);
+	if (err)
+		return err;
+
+	sbi->s_buddy_cache = new_inode(sb);
+	if (sbi->s_buddy_cache == NULL) {
+		ext4_msg(sb, KERN_ERR, "can't get new inode");
+		goto err_freesgi;
+	}
+	/* To avoid potentially colliding with an valid on-disk inode number,
+	 * use EXT4_BAD_INO for the buddy cache inode number.  This inode is
+	 * not in the inode hash, so it should never be found by iget(), but
+	 * this will avoid confusion if it ever shows up during debugging. */
+	sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
+	EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
+	for (i = 0; i < ngroups; i++) {
+		cond_resched();
+		desc = ext4_get_group_desc(sb, i, NULL);
+		if (desc == NULL) {
+			ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
+			goto err_freebuddy;
+		}
+		if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
+			goto err_freebuddy;
+	}
+
+	if (ext4_has_feature_flex_bg(sb)) {
+		/* a single flex group is supposed to be read by a single IO.
+		 * 2 ^ s_log_groups_per_flex != UINT_MAX as s_mb_prefetch is
+		 * unsigned integer, so the maximum shift is 32.
+		 */
+		if (sbi->s_es->s_log_groups_per_flex >= 32) {
+			ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group");
+			goto err_freebuddy;
+		}
+		sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex,
+			BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9));
+		sbi->s_mb_prefetch *= 8; /* 8 prefetch IOs in flight at most */
+	} else {
+		sbi->s_mb_prefetch = 32;
+	}
+	if (sbi->s_mb_prefetch > ext4_get_groups_count(sb))
+		sbi->s_mb_prefetch = ext4_get_groups_count(sb);
+	/* now many real IOs to prefetch within a single allocation at cr=0
+	 * given cr=0 is an CPU-related optimization we shouldn't try to
+	 * load too many groups, at some point we should start to use what
+	 * we've got in memory.
+	 * with an average random access time 5ms, it'd take a second to get
+	 * 200 groups (* N with flex_bg), so let's make this limit 4
+	 */
+	sbi->s_mb_prefetch_limit = sbi->s_mb_prefetch * 4;
+	if (sbi->s_mb_prefetch_limit > ext4_get_groups_count(sb))
+		sbi->s_mb_prefetch_limit = ext4_get_groups_count(sb);
+
+	return 0;
+
+err_freebuddy:
+	cachep = get_groupinfo_cache(sb->s_blocksize_bits);
+	while (i-- > 0) {
+		struct ext4_group_info *grp = ext4_get_group_info(sb, i);
+
+		if (grp)
+			kmem_cache_free(cachep, grp);
+	}
+	i = sbi->s_group_info_size;
+	rcu_read_lock();
+	group_info = rcu_dereference(sbi->s_group_info);
+	while (i-- > 0)
+		kfree(group_info[i]);
+	rcu_read_unlock();
+	iput(sbi->s_buddy_cache);
+err_freesgi:
+	rcu_read_lock();
+	kvfree(rcu_dereference(sbi->s_group_info));
+	rcu_read_unlock();
+	return -ENOMEM;
+}
+
+static void ext4_groupinfo_destroy_slabs(void)
+{
+	int i;
+
+	for (i = 0; i < NR_GRPINFO_CACHES; i++) {
+		kmem_cache_destroy(ext4_groupinfo_caches[i]);
+		ext4_groupinfo_caches[i] = NULL;
+	}
+}
+
+static int ext4_groupinfo_create_slab(size_t size)
+{
+	static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
+	int slab_size;
+	int blocksize_bits = order_base_2(size);
+	int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
+	struct kmem_cache *cachep;
+
+	if (cache_index >= NR_GRPINFO_CACHES)
+		return -EINVAL;
+
+	if (unlikely(cache_index < 0))
+		cache_index = 0;
+
+	mutex_lock(&ext4_grpinfo_slab_create_mutex);
+	if (ext4_groupinfo_caches[cache_index]) {
+		mutex_unlock(&ext4_grpinfo_slab_create_mutex);
+		return 0;	/* Already created */
+	}
+
+	slab_size = offsetof(struct ext4_group_info,
+				bb_counters[blocksize_bits + 2]);
+
+	cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
+					slab_size, 0, SLAB_RECLAIM_ACCOUNT,
+					NULL);
+
+	ext4_groupinfo_caches[cache_index] = cachep;
+
+	mutex_unlock(&ext4_grpinfo_slab_create_mutex);
+	if (!cachep) {
+		printk(KERN_EMERG
+		       "EXT4-fs: no memory for groupinfo slab cache\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int ext4_mb_init(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	unsigned i, j;
+	unsigned offset, offset_incr;
+	unsigned max;
+	int ret;
+
+	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
+
+	sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
+	if (sbi->s_mb_offsets == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
+	sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
+	if (sbi->s_mb_maxs == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = ext4_groupinfo_create_slab(sb->s_blocksize);
+	if (ret < 0)
+		goto out;
+
+	/* order 0 is regular bitmap */
+	sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
+	sbi->s_mb_offsets[0] = 0;
+
+	i = 1;
+	offset = 0;
+	offset_incr = 1 << (sb->s_blocksize_bits - 1);
+	max = sb->s_blocksize << 2;
+	do {
+		sbi->s_mb_offsets[i] = offset;
+		sbi->s_mb_maxs[i] = max;
+		offset += offset_incr;
+		offset_incr = offset_incr >> 1;
+		max = max >> 1;
+		i++;
+	} while (i <= sb->s_blocksize_bits + 1);
+
+	spin_lock_init(&sbi->s_md_lock);
+	sbi->s_mb_free_pending = 0;
+	INIT_LIST_HEAD(&sbi->s_freed_data_list);
+
+	sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
+	sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
+	sbi->s_mb_stats = MB_DEFAULT_STATS;
+	sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
+	sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
+	sbi->s_mb_max_inode_prealloc = MB_DEFAULT_MAX_INODE_PREALLOC;
+	/*
+	 * The default group preallocation is 512, which for 4k block
+	 * sizes translates to 2 megabytes.  However for bigalloc file
+	 * systems, this is probably too big (i.e, if the cluster size
+	 * is 1 megabyte, then group preallocation size becomes half a
+	 * gigabyte!).  As a default, we will keep a two megabyte
+	 * group pralloc size for cluster sizes up to 64k, and after
+	 * that, we will force a minimum group preallocation size of
+	 * 32 clusters.  This translates to 8 megs when the cluster
+	 * size is 256k, and 32 megs when the cluster size is 1 meg,
+	 * which seems reasonable as a default.
+	 */
+	sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
+				       sbi->s_cluster_bits, 32);
+	/*
+	 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
+	 * to the lowest multiple of s_stripe which is bigger than
+	 * the s_mb_group_prealloc as determined above. We want
+	 * the preallocation size to be an exact multiple of the
+	 * RAID stripe size so that preallocations don't fragment
+	 * the stripes.
+	 */
+	if (sbi->s_stripe > 1) {
+		sbi->s_mb_group_prealloc = roundup(
+			sbi->s_mb_group_prealloc, sbi->s_stripe);
+	}
+
+	sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
+	if (sbi->s_locality_groups == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	for_each_possible_cpu(i) {
+		struct ext4_locality_group *lg;
+		lg = per_cpu_ptr(sbi->s_locality_groups, i);
+		mutex_init(&lg->lg_mutex);
+		for (j = 0; j < PREALLOC_TB_SIZE; j++)
+			INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
+		spin_lock_init(&lg->lg_prealloc_lock);
+	}
+
+	/* init file for buddy data */
+	ret = ext4_mb_init_backend(sb);
+	if (ret != 0)
+		goto out_free_locality_groups;
+
+	return 0;
+
+out_free_locality_groups:
+	free_percpu(sbi->s_locality_groups);
+	sbi->s_locality_groups = NULL;
+out:
+	kfree(sbi->s_mb_offsets);
+	sbi->s_mb_offsets = NULL;
+	kfree(sbi->s_mb_maxs);
+	sbi->s_mb_maxs = NULL;
+	return ret;
+}
+
+/* need to called with the ext4 group lock held */
+static int ext4_mb_cleanup_pa(struct ext4_group_info *grp)
+{
+	struct ext4_prealloc_space *pa;
+	struct list_head *cur, *tmp;
+	int count = 0;
+
+	list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
+		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
+		list_del(&pa->pa_group_list);
+		count++;
+		kmem_cache_free(ext4_pspace_cachep, pa);
+	}
+	return count;
+}
+
+int ext4_mb_release(struct super_block *sb)
+{
+	ext4_group_t ngroups = ext4_get_groups_count(sb);
+	ext4_group_t i;
+	int num_meta_group_infos;
+	struct ext4_group_info *grinfo, ***group_info;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
+	int count;
+
+	if (sbi->s_group_info) {
+		for (i = 0; i < ngroups; i++) {
+			cond_resched();
+			grinfo = ext4_get_group_info(sb, i);
+			if (!grinfo)
+				continue;
+			mb_group_bb_bitmap_free(grinfo);
+			ext4_lock_group(sb, i);
+			count = ext4_mb_cleanup_pa(grinfo);
+			if (count)
+				mb_debug(sb, "mballoc: %d PAs left\n",
+					 count);
+			ext4_unlock_group(sb, i);
+			kmem_cache_free(cachep, grinfo);
+		}
+		num_meta_group_infos = (ngroups +
+				EXT4_DESC_PER_BLOCK(sb) - 1) >>
+			EXT4_DESC_PER_BLOCK_BITS(sb);
+		rcu_read_lock();
+		group_info = rcu_dereference(sbi->s_group_info);
+		for (i = 0; i < num_meta_group_infos; i++)
+			kfree(group_info[i]);
+		kvfree(group_info);
+		rcu_read_unlock();
+	}
+	kfree(sbi->s_mb_offsets);
+	kfree(sbi->s_mb_maxs);
+	iput(sbi->s_buddy_cache);
+	if (sbi->s_mb_stats) {
+		ext4_msg(sb, KERN_INFO,
+		       "mballoc: %u blocks %u reqs (%u success)",
+				atomic_read(&sbi->s_bal_allocated),
+				atomic_read(&sbi->s_bal_reqs),
+				atomic_read(&sbi->s_bal_success));
+		ext4_msg(sb, KERN_INFO,
+		      "mballoc: %u extents scanned, %u groups scanned, %u goal hits, "
+				"%u 2^N hits, %u breaks, %u lost",
+				atomic_read(&sbi->s_bal_ex_scanned),
+				atomic_read(&sbi->s_bal_groups_scanned),
+				atomic_read(&sbi->s_bal_goals),
+				atomic_read(&sbi->s_bal_2orders),
+				atomic_read(&sbi->s_bal_breaks),
+				atomic_read(&sbi->s_mb_lost_chunks));
+		ext4_msg(sb, KERN_INFO,
+		       "mballoc: %u generated and it took %llu",
+				atomic_read(&sbi->s_mb_buddies_generated),
+				atomic64_read(&sbi->s_mb_generation_time));
+		ext4_msg(sb, KERN_INFO,
+		       "mballoc: %u preallocated, %u discarded",
+				atomic_read(&sbi->s_mb_preallocated),
+				atomic_read(&sbi->s_mb_discarded));
+	}
+
+	free_percpu(sbi->s_locality_groups);
+
+	return 0;
+}
+
+static inline int ext4_issue_discard(struct super_block *sb,
+		ext4_group_t block_group, ext4_grpblk_t cluster, int count,
+		struct bio **biop)
+{
+	ext4_fsblk_t discard_block;
+
+	discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
+			 ext4_group_first_block_no(sb, block_group));
+	count = EXT4_C2B(EXT4_SB(sb), count);
+	trace_ext4_discard_blocks(sb,
+			(unsigned long long) discard_block, count);
+	if (biop) {
+		return __blkdev_issue_discard(sb->s_bdev,
+			(sector_t)discard_block << (sb->s_blocksize_bits - 9),
+			(sector_t)count << (sb->s_blocksize_bits - 9),
+			GFP_NOFS, 0, biop);
+	} else
+		return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
+}
+
+static void ext4_free_data_in_buddy(struct super_block *sb,
+				    struct ext4_free_data *entry)
+{
+	struct ext4_buddy e4b;
+	struct ext4_group_info *db;
+	int err, count = 0, count2 = 0;
+
+	mb_debug(sb, "gonna free %u blocks in group %u (0x%p):",
+		 entry->efd_count, entry->efd_group, entry);
+
+	err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
+	/* we expect to find existing buddy because it's pinned */
+	BUG_ON(err != 0);
+
+	spin_lock(&EXT4_SB(sb)->s_md_lock);
+	EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count;
+	spin_unlock(&EXT4_SB(sb)->s_md_lock);
+
+	db = e4b.bd_info;
+	/* there are blocks to put in buddy to make them really free */
+	count += entry->efd_count;
+	count2++;
+	ext4_lock_group(sb, entry->efd_group);
+	/* Take it out of per group rb tree */
+	rb_erase(&entry->efd_node, &(db->bb_free_root));
+	mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
+
+	/*
+	 * Clear the trimmed flag for the group so that the next
+	 * ext4_trim_fs can trim it.
+	 * If the volume is mounted with -o discard, online discard
+	 * is supported and the free blocks will be trimmed online.
+	 */
+	if (!test_opt(sb, DISCARD))
+		EXT4_MB_GRP_CLEAR_TRIMMED(db);
+
+	if (!db->bb_free_root.rb_node) {
+		/* No more items in the per group rb tree
+		 * balance refcounts from ext4_mb_free_metadata()
+		 */
+		put_page(e4b.bd_buddy_page);
+		put_page(e4b.bd_bitmap_page);
+	}
+	ext4_unlock_group(sb, entry->efd_group);
+	kmem_cache_free(ext4_free_data_cachep, entry);
+	ext4_mb_unload_buddy(&e4b);
+
+	mb_debug(sb, "freed %d blocks in %d structures\n", count,
+		 count2);
+}
+
+/*
+ * This function is called by the jbd2 layer once the commit has finished,
+ * so we know we can free the blocks that were released with that commit.
+ */
+void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_free_data *entry, *tmp;
+	struct bio *discard_bio = NULL;
+	struct list_head freed_data_list;
+	struct list_head *cut_pos = NULL;
+	int err;
+
+	INIT_LIST_HEAD(&freed_data_list);
+
+	spin_lock(&sbi->s_md_lock);
+	list_for_each_entry(entry, &sbi->s_freed_data_list, efd_list) {
+		if (entry->efd_tid != commit_tid)
+			break;
+		cut_pos = &entry->efd_list;
+	}
+	if (cut_pos)
+		list_cut_position(&freed_data_list, &sbi->s_freed_data_list,
+				  cut_pos);
+	spin_unlock(&sbi->s_md_lock);
+
+	if (test_opt(sb, DISCARD)) {
+		list_for_each_entry(entry, &freed_data_list, efd_list) {
+			err = ext4_issue_discard(sb, entry->efd_group,
+						 entry->efd_start_cluster,
+						 entry->efd_count,
+						 &discard_bio);
+			if (err && err != -EOPNOTSUPP) {
+				ext4_msg(sb, KERN_WARNING, "discard request in"
+					 " group:%d block:%d count:%d failed"
+					 " with %d", entry->efd_group,
+					 entry->efd_start_cluster,
+					 entry->efd_count, err);
+			} else if (err == -EOPNOTSUPP)
+				break;
+		}
+
+		if (discard_bio) {
+			submit_bio_wait(discard_bio);
+			bio_put(discard_bio);
+		}
+	}
+
+	list_for_each_entry_safe(entry, tmp, &freed_data_list, efd_list)
+		ext4_free_data_in_buddy(sb, entry);
+}
+
+int __init ext4_init_mballoc(void)
+{
+	ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
+					SLAB_RECLAIM_ACCOUNT);
+	if (ext4_pspace_cachep == NULL)
+		goto out;
+
+	ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
+				    SLAB_RECLAIM_ACCOUNT);
+	if (ext4_ac_cachep == NULL)
+		goto out_pa_free;
+
+	ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
+					   SLAB_RECLAIM_ACCOUNT);
+	if (ext4_free_data_cachep == NULL)
+		goto out_ac_free;
+
+	return 0;
+
+out_ac_free:
+	kmem_cache_destroy(ext4_ac_cachep);
+out_pa_free:
+	kmem_cache_destroy(ext4_pspace_cachep);
+out:
+	return -ENOMEM;
+}
+
+void ext4_exit_mballoc(void)
+{
+	/*
+	 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
+	 * before destroying the slab cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(ext4_pspace_cachep);
+	kmem_cache_destroy(ext4_ac_cachep);
+	kmem_cache_destroy(ext4_free_data_cachep);
+	ext4_groupinfo_destroy_slabs();
+}
+
+
+/*
+ * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
+ * Returns 0 if success or error code
+ */
+static noinline_for_stack int
+ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
+				handle_t *handle, unsigned int reserv_clstrs)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct ext4_group_desc *gdp;
+	struct buffer_head *gdp_bh;
+	struct ext4_sb_info *sbi;
+	struct super_block *sb;
+	ext4_fsblk_t block;
+	int err, len;
+
+	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
+	BUG_ON(ac->ac_b_ex.fe_len <= 0);
+
+	sb = ac->ac_sb;
+	sbi = EXT4_SB(sb);
+
+	bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
+	if (IS_ERR(bitmap_bh)) {
+		err = PTR_ERR(bitmap_bh);
+		bitmap_bh = NULL;
+		goto out_err;
+	}
+
+	BUFFER_TRACE(bitmap_bh, "getting write access");
+	err = ext4_journal_get_write_access(handle, bitmap_bh);
+	if (err)
+		goto out_err;
+
+	err = -EIO;
+	gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
+	if (!gdp)
+		goto out_err;
+
+	ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
+			ext4_free_group_clusters(sb, gdp));
+
+	BUFFER_TRACE(gdp_bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, gdp_bh);
+	if (err)
+		goto out_err;
+
+	block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+
+	len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+	if (!ext4_inode_block_valid(ac->ac_inode, block, len)) {
+		ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
+			   "fs metadata", block, block+len);
+		/* File system mounted not to panic on error
+		 * Fix the bitmap and return EFSCORRUPTED
+		 * We leak some of the blocks here.
+		 */
+		ext4_lock_group(sb, ac->ac_b_ex.fe_group);
+		ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
+			      ac->ac_b_ex.fe_len);
+		ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
+		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+		if (!err)
+			err = -EFSCORRUPTED;
+		goto out_err;
+	}
+
+	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
+#ifdef AGGRESSIVE_CHECK
+	{
+		int i;
+		for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
+			BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
+						bitmap_bh->b_data));
+		}
+	}
+#endif
+	ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
+		      ac->ac_b_ex.fe_len);
+	if (ext4_has_group_desc_csum(sb) &&
+	    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+		ext4_free_group_clusters_set(sb, gdp,
+					     ext4_free_clusters_after_init(sb,
+						ac->ac_b_ex.fe_group, gdp));
+	}
+	len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
+	ext4_free_group_clusters_set(sb, gdp, len);
+	ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh);
+	ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
+
+	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
+	percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
+	/*
+	 * Now reduce the dirty block count also. Should not go negative
+	 */
+	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
+		/* release all the reserved blocks if non delalloc */
+		percpu_counter_sub(&sbi->s_dirtyclusters_counter,
+				   reserv_clstrs);
+
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi,
+							  ac->ac_b_ex.fe_group);
+		atomic64_sub(ac->ac_b_ex.fe_len,
+			     &sbi_array_rcu_deref(sbi, s_flex_groups,
+						  flex_group)->free_clusters);
+	}
+
+	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+	if (err)
+		goto out_err;
+	err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
+
+out_err:
+	brelse(bitmap_bh);
+	return err;
+}
+
+/*
+ * Idempotent helper for Ext4 fast commit replay path to set the state of
+ * blocks in bitmaps and update counters.
+ */
+void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
+			int len, int state)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct ext4_group_desc *gdp;
+	struct buffer_head *gdp_bh;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_group_t group;
+	ext4_grpblk_t blkoff;
+	int i, err;
+	int already;
+	unsigned int clen, clen_changed, thisgrp_len;
+
+	while (len > 0) {
+		ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
+
+		/*
+		 * Check to see if we are freeing blocks across a group
+		 * boundary.
+		 * In case of flex_bg, this can happen that (block, len) may
+		 * span across more than one group. In that case we need to
+		 * get the corresponding group metadata to work with.
+		 * For this we have goto again loop.
+		 */
+		thisgrp_len = min_t(unsigned int, (unsigned int)len,
+			EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
+		clen = EXT4_NUM_B2C(sbi, thisgrp_len);
+
+		bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (IS_ERR(bitmap_bh)) {
+			err = PTR_ERR(bitmap_bh);
+			bitmap_bh = NULL;
+			break;
+		}
+
+		err = -EIO;
+		gdp = ext4_get_group_desc(sb, group, &gdp_bh);
+		if (!gdp)
+			break;
+
+		ext4_lock_group(sb, group);
+		already = 0;
+		for (i = 0; i < clen; i++)
+			if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
+					 !state)
+				already++;
+
+		clen_changed = clen - already;
+		if (state)
+			ext4_set_bits(bitmap_bh->b_data, blkoff, clen);
+		else
+			mb_test_and_clear_bits(bitmap_bh->b_data, blkoff, clen);
+		if (ext4_has_group_desc_csum(sb) &&
+		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+			ext4_free_group_clusters_set(sb, gdp,
+			     ext4_free_clusters_after_init(sb, group, gdp));
+		}
+		if (state)
+			clen = ext4_free_group_clusters(sb, gdp) - clen_changed;
+		else
+			clen = ext4_free_group_clusters(sb, gdp) + clen_changed;
+
+		ext4_free_group_clusters_set(sb, gdp, clen);
+		ext4_block_bitmap_csum_set(sb, group, gdp, bitmap_bh);
+		ext4_group_desc_csum_set(sb, group, gdp);
+
+		ext4_unlock_group(sb, group);
+
+		if (sbi->s_log_groups_per_flex) {
+			ext4_group_t flex_group = ext4_flex_group(sbi, group);
+			struct flex_groups *fg = sbi_array_rcu_deref(sbi,
+						   s_flex_groups, flex_group);
+
+			if (state)
+				atomic64_sub(clen_changed, &fg->free_clusters);
+			else
+				atomic64_add(clen_changed, &fg->free_clusters);
+
+		}
+
+		err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
+		if (err)
+			break;
+		sync_dirty_buffer(bitmap_bh);
+		err = ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
+		sync_dirty_buffer(gdp_bh);
+		if (err)
+			break;
+
+		block += thisgrp_len;
+		len -= thisgrp_len;
+		brelse(bitmap_bh);
+		BUG_ON(len < 0);
+	}
+
+	if (err)
+		brelse(bitmap_bh);
+}
+
+/*
+ * here we normalize request for locality group
+ * Group request are normalized to s_mb_group_prealloc, which goes to
+ * s_strip if we set the same via mount option.
+ * s_mb_group_prealloc can be configured via
+ * /sys/fs/ext4/<partition>/mb_group_prealloc
+ *
+ * XXX: should we try to preallocate more than the group has now?
+ */
+static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
+{
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_locality_group *lg = ac->ac_lg;
+
+	BUG_ON(lg == NULL);
+	ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
+	mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len);
+}
+
+/*
+ * Normalization means making request better in terms of
+ * size and alignment
+ */
+static noinline_for_stack void
+ext4_mb_normalize_request(struct ext4_allocation_context *ac,
+				struct ext4_allocation_request *ar)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	struct ext4_super_block *es = sbi->s_es;
+	int bsbits, max;
+	loff_t size, start_off, end;
+	loff_t orig_size __maybe_unused;
+	ext4_lblk_t start;
+	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
+	struct ext4_prealloc_space *pa;
+
+	/* do normalize only data requests, metadata requests
+	   do not need preallocation */
+	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
+		return;
+
+	/* sometime caller may want exact blocks */
+	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
+		return;
+
+	/* caller may indicate that preallocation isn't
+	 * required (it's a tail, for example) */
+	if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
+		return;
+
+	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
+		ext4_mb_normalize_group_request(ac);
+		return ;
+	}
+
+	bsbits = ac->ac_sb->s_blocksize_bits;
+
+	/* first, let's learn actual file size
+	 * given current request is allocated */
+	size = extent_logical_end(sbi, &ac->ac_o_ex);
+	size = size << bsbits;
+	if (size < i_size_read(ac->ac_inode))
+		size = i_size_read(ac->ac_inode);
+	orig_size = size;
+
+	/* max size of free chunks */
+	max = 2 << bsbits;
+
+#define NRL_CHECK_SIZE(req, size, max, chunk_size)	\
+		(req <= (size) || max <= (chunk_size))
+
+	/* first, try to predict filesize */
+	/* XXX: should this table be tunable? */
+	start_off = 0;
+	if (size <= 16 * 1024) {
+		size = 16 * 1024;
+	} else if (size <= 32 * 1024) {
+		size = 32 * 1024;
+	} else if (size <= 64 * 1024) {
+		size = 64 * 1024;
+	} else if (size <= 128 * 1024) {
+		size = 128 * 1024;
+	} else if (size <= 256 * 1024) {
+		size = 256 * 1024;
+	} else if (size <= 512 * 1024) {
+		size = 512 * 1024;
+	} else if (size <= 1024 * 1024) {
+		size = 1024 * 1024;
+	} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
+		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
+						(21 - bsbits)) << 21;
+		size = 2 * 1024 * 1024;
+	} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
+		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
+							(22 - bsbits)) << 22;
+		size = 4 * 1024 * 1024;
+	} else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
+					(8<<20)>>bsbits, max, 8 * 1024)) {
+		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
+							(23 - bsbits)) << 23;
+		size = 8 * 1024 * 1024;
+	} else {
+		start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
+		size	  = (loff_t) EXT4_C2B(EXT4_SB(ac->ac_sb),
+					      ac->ac_o_ex.fe_len) << bsbits;
+	}
+	size = size >> bsbits;
+	start = start_off >> bsbits;
+
+	/*
+	 * For tiny groups (smaller than 8MB) the chosen allocation
+	 * alignment may be larger than group size. Make sure the
+	 * alignment does not move allocation to a different group which
+	 * makes mballoc fail assertions later.
+	 */
+	start = max(start, rounddown(ac->ac_o_ex.fe_logical,
+			(ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb)));
+
+	/* avoid unnecessary preallocation that may trigger assertions */
+	if (start + size > EXT_MAX_BLOCKS)
+		size = EXT_MAX_BLOCKS - start;
+
+	/* don't cover already allocated blocks in selected range */
+	if (ar->pleft && start <= ar->lleft) {
+		size -= ar->lleft + 1 - start;
+		start = ar->lleft + 1;
+	}
+	if (ar->pright && start + size - 1 >= ar->lright)
+		size -= start + size - ar->lright;
+
+	/*
+	 * Trim allocation request for filesystems with artificially small
+	 * groups.
+	 */
+	if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
+		size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
+
+	end = start + size;
+
+	/* check we don't cross already preallocated blocks */
+	rcu_read_lock();
+	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
+		loff_t pa_end;
+
+		if (pa->pa_deleted)
+			continue;
+		spin_lock(&pa->pa_lock);
+		if (pa->pa_deleted) {
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+
+		pa_end = pa_logical_end(EXT4_SB(ac->ac_sb), pa);
+
+		/* PA must not overlap original request */
+		BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
+			ac->ac_o_ex.fe_logical < pa->pa_lstart));
+
+		/* skip PAs this normalized request doesn't overlap with */
+		if (pa->pa_lstart >= end || pa_end <= start) {
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+		BUG_ON(pa->pa_lstart <= start && pa_end >= end);
+
+		/* adjust start or end to be adjacent to this pa */
+		if (pa_end <= ac->ac_o_ex.fe_logical) {
+			BUG_ON(pa_end < start);
+			start = pa_end;
+		} else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
+			BUG_ON(pa->pa_lstart > end);
+			end = pa->pa_lstart;
+		}
+		spin_unlock(&pa->pa_lock);
+	}
+	rcu_read_unlock();
+	size = end - start;
+
+	/* XXX: extra loop to check we really don't overlap preallocations */
+	rcu_read_lock();
+	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
+		loff_t pa_end;
+
+		spin_lock(&pa->pa_lock);
+		if (pa->pa_deleted == 0) {
+			pa_end = pa_logical_end(EXT4_SB(ac->ac_sb), pa);
+			BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
+		}
+		spin_unlock(&pa->pa_lock);
+	}
+	rcu_read_unlock();
+
+	if (start + size <= ac->ac_o_ex.fe_logical &&
+			start > ac->ac_o_ex.fe_logical) {
+		ext4_msg(ac->ac_sb, KERN_ERR,
+			 "start %lu, size %lu, fe_logical %lu",
+			 (unsigned long) start, (unsigned long) size,
+			 (unsigned long) ac->ac_o_ex.fe_logical);
+		BUG();
+	}
+	BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
+
+	/* now prepare goal request */
+
+	/* XXX: is it better to align blocks WRT to logical
+	 * placement or satisfy big request as is */
+	ac->ac_g_ex.fe_logical = start;
+	ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
+
+	/* define goal start in order to merge */
+	if (ar->pright && (ar->lright == (start + size)) &&
+	    ar->pright >= size &&
+	    ar->pright - size >= le32_to_cpu(es->s_first_data_block)) {
+		/* merge to the right */
+		ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
+						&ac->ac_g_ex.fe_group,
+						&ac->ac_g_ex.fe_start);
+		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
+	}
+	if (ar->pleft && (ar->lleft + 1 == start) &&
+	    ar->pleft + 1 < ext4_blocks_count(es)) {
+		/* merge to the left */
+		ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
+						&ac->ac_g_ex.fe_group,
+						&ac->ac_g_ex.fe_start);
+		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
+	}
+
+	mb_debug(ac->ac_sb, "goal: %lld(was %lld) blocks at %u\n", size,
+		 orig_size, start);
+}
+
+static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+
+	if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) {
+		atomic_inc(&sbi->s_bal_reqs);
+		atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
+		if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
+			atomic_inc(&sbi->s_bal_success);
+		atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
+		atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned);
+		if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
+				ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
+			atomic_inc(&sbi->s_bal_goals);
+		if (ac->ac_found > sbi->s_mb_max_to_scan)
+			atomic_inc(&sbi->s_bal_breaks);
+	}
+
+	if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
+		trace_ext4_mballoc_alloc(ac);
+	else
+		trace_ext4_mballoc_prealloc(ac);
+}
+
+/*
+ * Called on failure; free up any blocks from the inode PA for this
+ * context.  We don't need this for MB_GROUP_PA because we only change
+ * pa_free in ext4_mb_release_context(), but on failure, we've already
+ * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
+ */
+static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
+{
+	struct ext4_prealloc_space *pa = ac->ac_pa;
+	struct ext4_buddy e4b;
+	int err;
+
+	if (pa == NULL) {
+		if (ac->ac_f_ex.fe_len == 0)
+			return;
+		err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
+		if (err) {
+			/*
+			 * This should never happen since we pin the
+			 * pages in the ext4_allocation_context so
+			 * ext4_mb_load_buddy() should never fail.
+			 */
+			WARN(1, "mb_load_buddy failed (%d)", err);
+			return;
+		}
+		ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
+		mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
+			       ac->ac_f_ex.fe_len);
+		ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
+		ext4_mb_unload_buddy(&e4b);
+		return;
+	}
+	if (pa->pa_type == MB_INODE_PA)
+		pa->pa_free += ac->ac_b_ex.fe_len;
+}
+
+/*
+ * use blocks preallocated to inode
+ */
+static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
+				struct ext4_prealloc_space *pa)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	ext4_fsblk_t start;
+	ext4_fsblk_t end;
+	int len;
+
+	/* found preallocated blocks, use them */
+	start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
+	end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
+		  start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
+	len = EXT4_NUM_B2C(sbi, end - start);
+	ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
+					&ac->ac_b_ex.fe_start);
+	ac->ac_b_ex.fe_len = len;
+	ac->ac_status = AC_STATUS_FOUND;
+	ac->ac_pa = pa;
+
+	BUG_ON(start < pa->pa_pstart);
+	BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
+	BUG_ON(pa->pa_free < len);
+	BUG_ON(ac->ac_b_ex.fe_len <= 0);
+	pa->pa_free -= len;
+
+	mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa);
+}
+
+/*
+ * use blocks preallocated to locality group
+ */
+static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
+				struct ext4_prealloc_space *pa)
+{
+	unsigned int len = ac->ac_o_ex.fe_len;
+
+	ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
+					&ac->ac_b_ex.fe_group,
+					&ac->ac_b_ex.fe_start);
+	ac->ac_b_ex.fe_len = len;
+	ac->ac_status = AC_STATUS_FOUND;
+	ac->ac_pa = pa;
+
+	/* we don't correct pa_pstart or pa_plen here to avoid
+	 * possible race when the group is being loaded concurrently
+	 * instead we correct pa later, after blocks are marked
+	 * in on-disk bitmap -- see ext4_mb_release_context()
+	 * Other CPUs are prevented from allocating from this pa by lg_mutex
+	 */
+	mb_debug(ac->ac_sb, "use %u/%u from group pa %p\n",
+		 pa->pa_lstart-len, len, pa);
+}
+
+/*
+ * Return the prealloc space that have minimal distance
+ * from the goal block. @cpa is the prealloc
+ * space that is having currently known minimal distance
+ * from the goal block.
+ */
+static struct ext4_prealloc_space *
+ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
+			struct ext4_prealloc_space *pa,
+			struct ext4_prealloc_space *cpa)
+{
+	ext4_fsblk_t cur_distance, new_distance;
+
+	if (cpa == NULL) {
+		atomic_inc(&pa->pa_count);
+		return pa;
+	}
+	cur_distance = abs(goal_block - cpa->pa_pstart);
+	new_distance = abs(goal_block - pa->pa_pstart);
+
+	if (cur_distance <= new_distance)
+		return cpa;
+
+	/* drop the previous reference */
+	atomic_dec(&cpa->pa_count);
+	atomic_inc(&pa->pa_count);
+	return pa;
+}
+
+/*
+ * search goal blocks in preallocated space
+ */
+static noinline_for_stack bool
+ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	int order, i;
+	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
+	struct ext4_locality_group *lg;
+	struct ext4_prealloc_space *pa, *cpa = NULL;
+	ext4_fsblk_t goal_block;
+
+	/* only data can be preallocated */
+	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
+		return false;
+
+	/* first, try per-file preallocation */
+	rcu_read_lock();
+	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
+
+		/* all fields in this condition don't change,
+		 * so we can skip locking for them */
+		if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
+		    ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, pa))
+			continue;
+
+		/* non-extent files can't have physical blocks past 2^32 */
+		if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
+		    (pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len) >
+		     EXT4_MAX_BLOCK_FILE_PHYS))
+			continue;
+
+		/* found preallocated blocks, use them */
+		spin_lock(&pa->pa_lock);
+		if (pa->pa_deleted == 0 && pa->pa_free) {
+			atomic_inc(&pa->pa_count);
+			ext4_mb_use_inode_pa(ac, pa);
+			spin_unlock(&pa->pa_lock);
+			ac->ac_criteria = 10;
+			rcu_read_unlock();
+			return true;
+		}
+		spin_unlock(&pa->pa_lock);
+	}
+	rcu_read_unlock();
+
+	/* can we use group allocation? */
+	if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
+		return false;
+
+	/* inode may have no locality group for some reason */
+	lg = ac->ac_lg;
+	if (lg == NULL)
+		return false;
+	order  = fls(ac->ac_o_ex.fe_len) - 1;
+	if (order > PREALLOC_TB_SIZE - 1)
+		/* The max size of hash table is PREALLOC_TB_SIZE */
+		order = PREALLOC_TB_SIZE - 1;
+
+	goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
+	/*
+	 * search for the prealloc space that is having
+	 * minimal distance from the goal block.
+	 */
+	for (i = order; i < PREALLOC_TB_SIZE; i++) {
+		rcu_read_lock();
+		list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
+					pa_inode_list) {
+			spin_lock(&pa->pa_lock);
+			if (pa->pa_deleted == 0 &&
+					pa->pa_free >= ac->ac_o_ex.fe_len) {
+
+				cpa = ext4_mb_check_group_pa(goal_block,
+								pa, cpa);
+			}
+			spin_unlock(&pa->pa_lock);
+		}
+		rcu_read_unlock();
+	}
+	if (cpa) {
+		ext4_mb_use_group_pa(ac, cpa);
+		ac->ac_criteria = 20;
+		return true;
+	}
+	return false;
+}
+
+/*
+ * the function goes through all block freed in the group
+ * but not yet committed and marks them used in in-core bitmap.
+ * buddy must be generated from this bitmap
+ * Need to be called with the ext4 group lock held
+ */
+static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
+						ext4_group_t group)
+{
+	struct rb_node *n;
+	struct ext4_group_info *grp;
+	struct ext4_free_data *entry;
+
+	grp = ext4_get_group_info(sb, group);
+	if (!grp)
+		return;
+	n = rb_first(&(grp->bb_free_root));
+
+	while (n) {
+		entry = rb_entry(n, struct ext4_free_data, efd_node);
+		ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
+		n = rb_next(n);
+	}
+	return;
+}
+
+/*
+ * the function goes through all preallocation in this group and marks them
+ * used in in-core bitmap. buddy must be generated from this bitmap
+ * Need to be called with ext4 group lock held
+ */
+static noinline_for_stack
+void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
+					ext4_group_t group)
+{
+	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+	struct ext4_prealloc_space *pa;
+	struct list_head *cur;
+	ext4_group_t groupnr;
+	ext4_grpblk_t start;
+	int preallocated = 0;
+	int len;
+
+	if (!grp)
+		return;
+
+	/* all form of preallocation discards first load group,
+	 * so the only competing code is preallocation use.
+	 * we don't need any locking here
+	 * notice we do NOT ignore preallocations with pa_deleted
+	 * otherwise we could leave used blocks available for
+	 * allocation in buddy when concurrent ext4_mb_put_pa()
+	 * is dropping preallocation
+	 */
+	list_for_each(cur, &grp->bb_prealloc_list) {
+		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
+		spin_lock(&pa->pa_lock);
+		ext4_get_group_no_and_offset(sb, pa->pa_pstart,
+					     &groupnr, &start);
+		len = pa->pa_len;
+		spin_unlock(&pa->pa_lock);
+		if (unlikely(len == 0))
+			continue;
+		BUG_ON(groupnr != group);
+		ext4_set_bits(bitmap, start, len);
+		preallocated += len;
+	}
+	mb_debug(sb, "preallocated %d for group %u\n", preallocated, group);
+}
+
+static void ext4_mb_mark_pa_deleted(struct super_block *sb,
+				    struct ext4_prealloc_space *pa)
+{
+	struct ext4_inode_info *ei;
+
+	if (pa->pa_deleted) {
+		ext4_warning(sb, "deleted pa, type:%d, pblk:%llu, lblk:%u, len:%d\n",
+			     pa->pa_type, pa->pa_pstart, pa->pa_lstart,
+			     pa->pa_len);
+		return;
+	}
+
+	pa->pa_deleted = 1;
+
+	if (pa->pa_type == MB_INODE_PA) {
+		ei = EXT4_I(pa->pa_inode);
+		atomic_dec(&ei->i_prealloc_active);
+	}
+}
+
+static void ext4_mb_pa_callback(struct rcu_head *head)
+{
+	struct ext4_prealloc_space *pa;
+	pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
+
+	BUG_ON(atomic_read(&pa->pa_count));
+	BUG_ON(pa->pa_deleted == 0);
+	kmem_cache_free(ext4_pspace_cachep, pa);
+}
+
+/*
+ * drops a reference to preallocated space descriptor
+ * if this was the last reference and the space is consumed
+ */
+static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
+			struct super_block *sb, struct ext4_prealloc_space *pa)
+{
+	ext4_group_t grp;
+	ext4_fsblk_t grp_blk;
+
+	/* in this short window concurrent discard can set pa_deleted */
+	spin_lock(&pa->pa_lock);
+	if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
+		spin_unlock(&pa->pa_lock);
+		return;
+	}
+
+	if (pa->pa_deleted == 1) {
+		spin_unlock(&pa->pa_lock);
+		return;
+	}
+
+	ext4_mb_mark_pa_deleted(sb, pa);
+	spin_unlock(&pa->pa_lock);
+
+	grp_blk = pa->pa_pstart;
+	/*
+	 * If doing group-based preallocation, pa_pstart may be in the
+	 * next group when pa is used up
+	 */
+	if (pa->pa_type == MB_GROUP_PA)
+		grp_blk--;
+
+	grp = ext4_get_group_number(sb, grp_blk);
+
+	/*
+	 * possible race:
+	 *
+	 *  P1 (buddy init)			P2 (regular allocation)
+	 *					find block B in PA
+	 *  copy on-disk bitmap to buddy
+	 *  					mark B in on-disk bitmap
+	 *					drop PA from group
+	 *  mark all PAs in buddy
+	 *
+	 * thus, P1 initializes buddy with B available. to prevent this
+	 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
+	 * against that pair
+	 */
+	ext4_lock_group(sb, grp);
+	list_del(&pa->pa_group_list);
+	ext4_unlock_group(sb, grp);
+
+	spin_lock(pa->pa_obj_lock);
+	list_del_rcu(&pa->pa_inode_list);
+	spin_unlock(pa->pa_obj_lock);
+
+	call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+}
+
+/*
+ * creates new preallocated space for given inode
+ */
+static noinline_for_stack void
+ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
+{
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_prealloc_space *pa;
+	struct ext4_group_info *grp;
+	struct ext4_inode_info *ei;
+
+	/* preallocate only when found space is larger then requested */
+	BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
+	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
+	BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
+	BUG_ON(ac->ac_pa == NULL);
+
+	pa = ac->ac_pa;
+
+	if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
+		struct ext4_free_extent ex = {
+			.fe_logical = ac->ac_g_ex.fe_logical,
+			.fe_len = ac->ac_g_ex.fe_len,
+		};
+		loff_t orig_goal_end = extent_logical_end(sbi, &ex);
+
+		/* we can't allocate as much as normalizer wants.
+		 * so, found space must get proper lstart
+		 * to cover original request */
+		BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
+		BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
+
+		/*
+		 * Use the below logic for adjusting best extent as it keeps
+		 * fragmentation in check while ensuring logical range of best
+		 * extent doesn't overflow out of goal extent:
+		 *
+		 * 1. Check if best ex can be kept at end of goal and still
+		 *    cover original start
+		 * 2. Else, check if best ex can be kept at start of goal and
+		 *    still cover original start
+		 * 3. Else, keep the best ex at start of original request.
+		 */
+		ex.fe_len = ac->ac_b_ex.fe_len;
+
+		ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len);
+		if (ac->ac_o_ex.fe_logical >= ex.fe_logical)
+			goto adjust_bex;
+
+		ex.fe_logical = ac->ac_g_ex.fe_logical;
+		if (ac->ac_o_ex.fe_logical < extent_logical_end(sbi, &ex))
+			goto adjust_bex;
+
+		ex.fe_logical = ac->ac_o_ex.fe_logical;
+adjust_bex:
+		ac->ac_b_ex.fe_logical = ex.fe_logical;
+
+		BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
+		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
+		BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end);
+	}
+
+	/* preallocation can change ac_b_ex, thus we store actually
+	 * allocated blocks for history */
+	ac->ac_f_ex = ac->ac_b_ex;
+
+	pa->pa_lstart = ac->ac_b_ex.fe_logical;
+	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+	pa->pa_len = ac->ac_b_ex.fe_len;
+	pa->pa_free = pa->pa_len;
+	spin_lock_init(&pa->pa_lock);
+	INIT_LIST_HEAD(&pa->pa_inode_list);
+	INIT_LIST_HEAD(&pa->pa_group_list);
+	pa->pa_deleted = 0;
+	pa->pa_type = MB_INODE_PA;
+
+	mb_debug(sb, "new inode pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
+		 pa->pa_len, pa->pa_lstart);
+	trace_ext4_mb_new_inode_pa(ac, pa);
+
+	ext4_mb_use_inode_pa(ac, pa);
+	atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
+
+	ei = EXT4_I(ac->ac_inode);
+	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
+	if (!grp)
+		return;
+
+	pa->pa_obj_lock = &ei->i_prealloc_lock;
+	pa->pa_inode = ac->ac_inode;
+
+	list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
+
+	spin_lock(pa->pa_obj_lock);
+	list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
+	spin_unlock(pa->pa_obj_lock);
+	atomic_inc(&ei->i_prealloc_active);
+}
+
+/*
+ * creates new preallocated space for locality group inodes belongs to
+ */
+static noinline_for_stack void
+ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
+{
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_locality_group *lg;
+	struct ext4_prealloc_space *pa;
+	struct ext4_group_info *grp;
+
+	/* preallocate only when found space is larger then requested */
+	BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
+	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
+	BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
+	BUG_ON(ac->ac_pa == NULL);
+
+	pa = ac->ac_pa;
+
+	/* preallocation can change ac_b_ex, thus we store actually
+	 * allocated blocks for history */
+	ac->ac_f_ex = ac->ac_b_ex;
+
+	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+	pa->pa_lstart = pa->pa_pstart;
+	pa->pa_len = ac->ac_b_ex.fe_len;
+	pa->pa_free = pa->pa_len;
+	spin_lock_init(&pa->pa_lock);
+	INIT_LIST_HEAD(&pa->pa_inode_list);
+	INIT_LIST_HEAD(&pa->pa_group_list);
+	pa->pa_deleted = 0;
+	pa->pa_type = MB_GROUP_PA;
+
+	mb_debug(sb, "new group pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
+		 pa->pa_len, pa->pa_lstart);
+	trace_ext4_mb_new_group_pa(ac, pa);
+
+	ext4_mb_use_group_pa(ac, pa);
+	atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
+
+	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
+	if (!grp)
+		return;
+	lg = ac->ac_lg;
+	BUG_ON(lg == NULL);
+
+	pa->pa_obj_lock = &lg->lg_prealloc_lock;
+	pa->pa_inode = NULL;
+
+	list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
+
+	/*
+	 * We will later add the new pa to the right bucket
+	 * after updating the pa_free in ext4_mb_release_context
+	 */
+}
+
+static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
+{
+	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
+		ext4_mb_new_group_pa(ac);
+	else
+		ext4_mb_new_inode_pa(ac);
+}
+
+/*
+ * finds all unused blocks in on-disk bitmap, frees them in
+ * in-core bitmap and buddy.
+ * @pa must be unlinked from inode and group lists, so that
+ * nobody else can find/use it.
+ * the caller MUST hold group/inode locks.
+ * TODO: optimize the case when there are no in-core structures yet
+ */
+static noinline_for_stack int
+ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
+			struct ext4_prealloc_space *pa)
+{
+	struct super_block *sb = e4b->bd_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	unsigned int end;
+	unsigned int next;
+	ext4_group_t group;
+	ext4_grpblk_t bit;
+	unsigned long long grp_blk_start;
+	int free = 0;
+
+	BUG_ON(pa->pa_deleted == 0);
+	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
+	grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
+	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
+	end = bit + pa->pa_len;
+
+	while (bit < end) {
+		bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
+		if (bit >= end)
+			break;
+		next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
+		mb_debug(sb, "free preallocated %u/%u in group %u\n",
+			 (unsigned) ext4_group_first_block_no(sb, group) + bit,
+			 (unsigned) next - bit, (unsigned) group);
+		free += next - bit;
+
+		trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
+		trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
+						    EXT4_C2B(sbi, bit)),
+					       next - bit);
+		mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
+		bit = next + 1;
+	}
+	if (free != pa->pa_free) {
+		ext4_msg(e4b->bd_sb, KERN_CRIT,
+			 "pa %p: logic %lu, phys. %lu, len %d",
+			 pa, (unsigned long) pa->pa_lstart,
+			 (unsigned long) pa->pa_pstart,
+			 pa->pa_len);
+		ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
+					free, pa->pa_free);
+		/*
+		 * pa is already deleted so we use the value obtained
+		 * from the bitmap and continue.
+		 */
+	}
+	atomic_add(free, &sbi->s_mb_discarded);
+
+	return 0;
+}
+
+static noinline_for_stack int
+ext4_mb_release_group_pa(struct ext4_buddy *e4b,
+				struct ext4_prealloc_space *pa)
+{
+	struct super_block *sb = e4b->bd_sb;
+	ext4_group_t group;
+	ext4_grpblk_t bit;
+
+	trace_ext4_mb_release_group_pa(sb, pa);
+	BUG_ON(pa->pa_deleted == 0);
+	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
+	if (unlikely(group != e4b->bd_group && pa->pa_len != 0)) {
+		ext4_warning(sb, "bad group: expected %u, group %u, pa_start %llu",
+			     e4b->bd_group, group, pa->pa_pstart);
+		return 0;
+	}
+	mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
+	atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
+	trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
+
+	return 0;
+}
+
+/*
+ * releases all preallocations in given group
+ *
+ * first, we need to decide discard policy:
+ * - when do we discard
+ *   1) ENOSPC
+ * - how many do we discard
+ *   1) how many requested
+ */
+static noinline_for_stack int
+ext4_mb_discard_group_preallocations(struct super_block *sb,
+				     ext4_group_t group, int *busy)
+{
+	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+	struct buffer_head *bitmap_bh = NULL;
+	struct ext4_prealloc_space *pa, *tmp;
+	struct list_head list;
+	struct ext4_buddy e4b;
+	int err;
+	int free = 0;
+
+	if (!grp)
+		return 0;
+	mb_debug(sb, "discard preallocation for group %u\n", group);
+	if (list_empty(&grp->bb_prealloc_list))
+		goto out_dbg;
+
+	bitmap_bh = ext4_read_block_bitmap(sb, group);
+	if (IS_ERR(bitmap_bh)) {
+		err = PTR_ERR(bitmap_bh);
+		ext4_error_err(sb, -err,
+			       "Error %d reading block bitmap for %u",
+			       err, group);
+		goto out_dbg;
+	}
+
+	err = ext4_mb_load_buddy(sb, group, &e4b);
+	if (err) {
+		ext4_warning(sb, "Error %d loading buddy information for %u",
+			     err, group);
+		put_bh(bitmap_bh);
+		goto out_dbg;
+	}
+
+	INIT_LIST_HEAD(&list);
+	ext4_lock_group(sb, group);
+	list_for_each_entry_safe(pa, tmp,
+				&grp->bb_prealloc_list, pa_group_list) {
+		spin_lock(&pa->pa_lock);
+		if (atomic_read(&pa->pa_count)) {
+			spin_unlock(&pa->pa_lock);
+			*busy = 1;
+			continue;
+		}
+		if (pa->pa_deleted) {
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+
+		/* seems this one can be freed ... */
+		ext4_mb_mark_pa_deleted(sb, pa);
+
+		if (!free)
+			this_cpu_inc(discard_pa_seq);
+
+		/* we can trust pa_free ... */
+		free += pa->pa_free;
+
+		spin_unlock(&pa->pa_lock);
+
+		list_del(&pa->pa_group_list);
+		list_add(&pa->u.pa_tmp_list, &list);
+	}
+
+	/* now free all selected PAs */
+	list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
+
+		/* remove from object (inode or locality group) */
+		spin_lock(pa->pa_obj_lock);
+		list_del_rcu(&pa->pa_inode_list);
+		spin_unlock(pa->pa_obj_lock);
+
+		if (pa->pa_type == MB_GROUP_PA)
+			ext4_mb_release_group_pa(&e4b, pa);
+		else
+			ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
+
+		list_del(&pa->u.pa_tmp_list);
+		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+	}
+
+	ext4_unlock_group(sb, group);
+	ext4_mb_unload_buddy(&e4b);
+	put_bh(bitmap_bh);
+out_dbg:
+	mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n",
+		 free, group, grp->bb_free);
+	return free;
+}
+
+/*
+ * releases all non-used preallocated blocks for given inode
+ *
+ * It's important to discard preallocations under i_data_sem
+ * We don't want another block to be served from the prealloc
+ * space when we are discarding the inode prealloc space.
+ *
+ * FIXME!! Make sure it is valid at all the call sites
+ */
+void ext4_discard_preallocations(struct inode *inode, unsigned int needed)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *bitmap_bh = NULL;
+	struct ext4_prealloc_space *pa, *tmp;
+	ext4_group_t group = 0;
+	struct list_head list;
+	struct ext4_buddy e4b;
+	int err;
+
+	if (!S_ISREG(inode->i_mode)) {
+		/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
+		return;
+	}
+
+	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
+		return;
+
+	mb_debug(sb, "discard preallocation for inode %lu\n",
+		 inode->i_ino);
+	trace_ext4_discard_preallocations(inode,
+			atomic_read(&ei->i_prealloc_active), needed);
+
+	INIT_LIST_HEAD(&list);
+
+	if (needed == 0)
+		needed = UINT_MAX;
+
+repeat:
+	/* first, collect all pa's in the inode */
+	spin_lock(&ei->i_prealloc_lock);
+	while (!list_empty(&ei->i_prealloc_list) && needed) {
+		pa = list_entry(ei->i_prealloc_list.prev,
+				struct ext4_prealloc_space, pa_inode_list);
+		BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
+		spin_lock(&pa->pa_lock);
+		if (atomic_read(&pa->pa_count)) {
+			/* this shouldn't happen often - nobody should
+			 * use preallocation while we're discarding it */
+			spin_unlock(&pa->pa_lock);
+			spin_unlock(&ei->i_prealloc_lock);
+			ext4_msg(sb, KERN_ERR,
+				 "uh-oh! used pa while discarding");
+			WARN_ON(1);
+			schedule_timeout_uninterruptible(HZ);
+			goto repeat;
+
+		}
+		if (pa->pa_deleted == 0) {
+			ext4_mb_mark_pa_deleted(sb, pa);
+			spin_unlock(&pa->pa_lock);
+			list_del_rcu(&pa->pa_inode_list);
+			list_add(&pa->u.pa_tmp_list, &list);
+			needed--;
+			continue;
+		}
+
+		/* someone is deleting pa right now */
+		spin_unlock(&pa->pa_lock);
+		spin_unlock(&ei->i_prealloc_lock);
+
+		/* we have to wait here because pa_deleted
+		 * doesn't mean pa is already unlinked from
+		 * the list. as we might be called from
+		 * ->clear_inode() the inode will get freed
+		 * and concurrent thread which is unlinking
+		 * pa from inode's list may access already
+		 * freed memory, bad-bad-bad */
+
+		/* XXX: if this happens too often, we can
+		 * add a flag to force wait only in case
+		 * of ->clear_inode(), but not in case of
+		 * regular truncate */
+		schedule_timeout_uninterruptible(HZ);
+		goto repeat;
+	}
+	spin_unlock(&ei->i_prealloc_lock);
+
+	list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
+		BUG_ON(pa->pa_type != MB_INODE_PA);
+		group = ext4_get_group_number(sb, pa->pa_pstart);
+
+		err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
+					     GFP_NOFS|__GFP_NOFAIL);
+		if (err) {
+			ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
+				       err, group);
+			continue;
+		}
+
+		bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (IS_ERR(bitmap_bh)) {
+			err = PTR_ERR(bitmap_bh);
+			ext4_error_err(sb, -err, "Error %d reading block bitmap for %u",
+				       err, group);
+			ext4_mb_unload_buddy(&e4b);
+			continue;
+		}
+
+		ext4_lock_group(sb, group);
+		list_del(&pa->pa_group_list);
+		ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
+		ext4_unlock_group(sb, group);
+
+		ext4_mb_unload_buddy(&e4b);
+		put_bh(bitmap_bh);
+
+		list_del(&pa->u.pa_tmp_list);
+		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+	}
+}
+
+static int ext4_mb_pa_alloc(struct ext4_allocation_context *ac)
+{
+	struct ext4_prealloc_space *pa;
+
+	BUG_ON(ext4_pspace_cachep == NULL);
+	pa = kmem_cache_zalloc(ext4_pspace_cachep, GFP_NOFS);
+	if (!pa)
+		return -ENOMEM;
+	atomic_set(&pa->pa_count, 1);
+	ac->ac_pa = pa;
+	return 0;
+}
+
+static void ext4_mb_pa_free(struct ext4_allocation_context *ac)
+{
+	struct ext4_prealloc_space *pa = ac->ac_pa;
+
+	BUG_ON(!pa);
+	ac->ac_pa = NULL;
+	WARN_ON(!atomic_dec_and_test(&pa->pa_count));
+	kmem_cache_free(ext4_pspace_cachep, pa);
+}
+
+#ifdef CONFIG_EXT4_DEBUG
+static inline void ext4_mb_show_pa(struct super_block *sb)
+{
+	ext4_group_t i, ngroups;
+
+	if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
+		return;
+
+	ngroups = ext4_get_groups_count(sb);
+	mb_debug(sb, "groups: ");
+	for (i = 0; i < ngroups; i++) {
+		struct ext4_group_info *grp = ext4_get_group_info(sb, i);
+		struct ext4_prealloc_space *pa;
+		ext4_grpblk_t start;
+		struct list_head *cur;
+
+		if (!grp)
+			continue;
+		ext4_lock_group(sb, i);
+		list_for_each(cur, &grp->bb_prealloc_list) {
+			pa = list_entry(cur, struct ext4_prealloc_space,
+					pa_group_list);
+			spin_lock(&pa->pa_lock);
+			ext4_get_group_no_and_offset(sb, pa->pa_pstart,
+						     NULL, &start);
+			spin_unlock(&pa->pa_lock);
+			mb_debug(sb, "PA:%u:%d:%d\n", i, start,
+				 pa->pa_len);
+		}
+		ext4_unlock_group(sb, i);
+		mb_debug(sb, "%u: %d/%d\n", i, grp->bb_free,
+			 grp->bb_fragments);
+	}
+}
+
+static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
+{
+	struct super_block *sb = ac->ac_sb;
+
+	if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
+		return;
+
+	mb_debug(sb, "Can't allocate:"
+			" Allocation context details:");
+	mb_debug(sb, "status %u flags 0x%x",
+			ac->ac_status, ac->ac_flags);
+	mb_debug(sb, "orig %lu/%lu/%lu@%lu, "
+			"goal %lu/%lu/%lu@%lu, "
+			"best %lu/%lu/%lu@%lu cr %d",
+			(unsigned long)ac->ac_o_ex.fe_group,
+			(unsigned long)ac->ac_o_ex.fe_start,
+			(unsigned long)ac->ac_o_ex.fe_len,
+			(unsigned long)ac->ac_o_ex.fe_logical,
+			(unsigned long)ac->ac_g_ex.fe_group,
+			(unsigned long)ac->ac_g_ex.fe_start,
+			(unsigned long)ac->ac_g_ex.fe_len,
+			(unsigned long)ac->ac_g_ex.fe_logical,
+			(unsigned long)ac->ac_b_ex.fe_group,
+			(unsigned long)ac->ac_b_ex.fe_start,
+			(unsigned long)ac->ac_b_ex.fe_len,
+			(unsigned long)ac->ac_b_ex.fe_logical,
+			(int)ac->ac_criteria);
+	mb_debug(sb, "%u found", ac->ac_found);
+	ext4_mb_show_pa(sb);
+}
+#else
+static inline void ext4_mb_show_pa(struct super_block *sb)
+{
+	return;
+}
+static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
+{
+	ext4_mb_show_pa(ac->ac_sb);
+	return;
+}
+#endif
+
+/*
+ * We use locality group preallocation for small size file. The size of the
+ * file is determined by the current size or the resulting size after
+ * allocation which ever is larger
+ *
+ * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
+ */
+static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	int bsbits = ac->ac_sb->s_blocksize_bits;
+	loff_t size, isize;
+
+	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
+		return;
+
+	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
+		return;
+
+	size = extent_logical_end(sbi, &ac->ac_o_ex);
+	isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
+		>> bsbits;
+
+	if ((size == isize) && !ext4_fs_is_busy(sbi) &&
+	    !inode_is_open_for_write(ac->ac_inode)) {
+		ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
+		return;
+	}
+
+	if (sbi->s_mb_group_prealloc <= 0) {
+		ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
+		return;
+	}
+
+	/* don't use group allocation for large files */
+	size = max(size, isize);
+	if (size > sbi->s_mb_stream_request) {
+		ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
+		return;
+	}
+
+	BUG_ON(ac->ac_lg != NULL);
+	/*
+	 * locality group prealloc space are per cpu. The reason for having
+	 * per cpu locality group is to reduce the contention between block
+	 * request from multiple CPUs.
+	 */
+	ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
+
+	/* we're going to use group allocation */
+	ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
+
+	/* serialize all allocations in the group */
+	mutex_lock(&ac->ac_lg->lg_mutex);
+}
+
+static noinline_for_stack int
+ext4_mb_initialize_context(struct ext4_allocation_context *ac,
+				struct ext4_allocation_request *ar)
+{
+	struct super_block *sb = ar->inode->i_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	ext4_group_t group;
+	unsigned int len;
+	ext4_fsblk_t goal;
+	ext4_grpblk_t block;
+
+	/* we can't allocate > group size */
+	len = ar->len;
+
+	/* just a dirty hack to filter too big requests  */
+	if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
+		len = EXT4_CLUSTERS_PER_GROUP(sb);
+
+	/* start searching from the goal */
+	goal = ar->goal;
+	if (goal < le32_to_cpu(es->s_first_data_block) ||
+			goal >= ext4_blocks_count(es))
+		goal = le32_to_cpu(es->s_first_data_block);
+	ext4_get_group_no_and_offset(sb, goal, &group, &block);
+
+	/* set up allocation goals */
+	ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
+	ac->ac_status = AC_STATUS_CONTINUE;
+	ac->ac_sb = sb;
+	ac->ac_inode = ar->inode;
+	ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
+	ac->ac_o_ex.fe_group = group;
+	ac->ac_o_ex.fe_start = block;
+	ac->ac_o_ex.fe_len = len;
+	ac->ac_g_ex = ac->ac_o_ex;
+	ac->ac_flags = ar->flags;
+
+	/* we have to define context: we'll work with a file or
+	 * locality group. this is a policy, actually */
+	ext4_mb_group_or_file(ac);
+
+	mb_debug(sb, "init ac: %u blocks @ %u, goal %u, flags 0x%x, 2^%d, "
+			"left: %u/%u, right %u/%u to %swritable\n",
+			(unsigned) ar->len, (unsigned) ar->logical,
+			(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
+			(unsigned) ar->lleft, (unsigned) ar->pleft,
+			(unsigned) ar->lright, (unsigned) ar->pright,
+			inode_is_open_for_write(ar->inode) ? "" : "non-");
+	return 0;
+
+}
+
+static noinline_for_stack void
+ext4_mb_discard_lg_preallocations(struct super_block *sb,
+					struct ext4_locality_group *lg,
+					int order, int total_entries)
+{
+	ext4_group_t group = 0;
+	struct ext4_buddy e4b;
+	struct list_head discard_list;
+	struct ext4_prealloc_space *pa, *tmp;
+
+	mb_debug(sb, "discard locality group preallocation\n");
+
+	INIT_LIST_HEAD(&discard_list);
+
+	spin_lock(&lg->lg_prealloc_lock);
+	list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
+				pa_inode_list,
+				lockdep_is_held(&lg->lg_prealloc_lock)) {
+		spin_lock(&pa->pa_lock);
+		if (atomic_read(&pa->pa_count)) {
+			/*
+			 * This is the pa that we just used
+			 * for block allocation. So don't
+			 * free that
+			 */
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+		if (pa->pa_deleted) {
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+		/* only lg prealloc space */
+		BUG_ON(pa->pa_type != MB_GROUP_PA);
+
+		/* seems this one can be freed ... */
+		ext4_mb_mark_pa_deleted(sb, pa);
+		spin_unlock(&pa->pa_lock);
+
+		list_del_rcu(&pa->pa_inode_list);
+		list_add(&pa->u.pa_tmp_list, &discard_list);
+
+		total_entries--;
+		if (total_entries <= 5) {
+			/*
+			 * we want to keep only 5 entries
+			 * allowing it to grow to 8. This
+			 * mak sure we don't call discard
+			 * soon for this list.
+			 */
+			break;
+		}
+	}
+	spin_unlock(&lg->lg_prealloc_lock);
+
+	list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
+		int err;
+
+		group = ext4_get_group_number(sb, pa->pa_pstart);
+		err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
+					     GFP_NOFS|__GFP_NOFAIL);
+		if (err) {
+			ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
+				       err, group);
+			continue;
+		}
+		ext4_lock_group(sb, group);
+		list_del(&pa->pa_group_list);
+		ext4_mb_release_group_pa(&e4b, pa);
+		ext4_unlock_group(sb, group);
+
+		ext4_mb_unload_buddy(&e4b);
+		list_del(&pa->u.pa_tmp_list);
+		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+	}
+}
+
+/*
+ * We have incremented pa_count. So it cannot be freed at this
+ * point. Also we hold lg_mutex. So no parallel allocation is
+ * possible from this lg. That means pa_free cannot be updated.
+ *
+ * A parallel ext4_mb_discard_group_preallocations is possible.
+ * which can cause the lg_prealloc_list to be updated.
+ */
+
+static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
+{
+	int order, added = 0, lg_prealloc_count = 1;
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_locality_group *lg = ac->ac_lg;
+	struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
+
+	order = fls(pa->pa_free) - 1;
+	if (order > PREALLOC_TB_SIZE - 1)
+		/* The max size of hash table is PREALLOC_TB_SIZE */
+		order = PREALLOC_TB_SIZE - 1;
+	/* Add the prealloc space to lg */
+	spin_lock(&lg->lg_prealloc_lock);
+	list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
+				pa_inode_list,
+				lockdep_is_held(&lg->lg_prealloc_lock)) {
+		spin_lock(&tmp_pa->pa_lock);
+		if (tmp_pa->pa_deleted) {
+			spin_unlock(&tmp_pa->pa_lock);
+			continue;
+		}
+		if (!added && pa->pa_free < tmp_pa->pa_free) {
+			/* Add to the tail of the previous entry */
+			list_add_tail_rcu(&pa->pa_inode_list,
+						&tmp_pa->pa_inode_list);
+			added = 1;
+			/*
+			 * we want to count the total
+			 * number of entries in the list
+			 */
+		}
+		spin_unlock(&tmp_pa->pa_lock);
+		lg_prealloc_count++;
+	}
+	if (!added)
+		list_add_tail_rcu(&pa->pa_inode_list,
+					&lg->lg_prealloc_list[order]);
+	spin_unlock(&lg->lg_prealloc_lock);
+
+	/* Now trim the list to be not more than 8 elements */
+	if (lg_prealloc_count > 8) {
+		ext4_mb_discard_lg_preallocations(sb, lg,
+						  order, lg_prealloc_count);
+		return;
+	}
+	return ;
+}
+
+/*
+ * if per-inode prealloc list is too long, trim some PA
+ */
+static void ext4_mb_trim_inode_pa(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int count, delta;
+
+	count = atomic_read(&ei->i_prealloc_active);
+	delta = (sbi->s_mb_max_inode_prealloc >> 2) + 1;
+	if (count > sbi->s_mb_max_inode_prealloc + delta) {
+		count -= sbi->s_mb_max_inode_prealloc;
+		ext4_discard_preallocations(inode, count);
+	}
+}
+
+/*
+ * release all resource we used in allocation
+ */
+static int ext4_mb_release_context(struct ext4_allocation_context *ac)
+{
+	struct inode *inode = ac->ac_inode;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+	struct ext4_prealloc_space *pa = ac->ac_pa;
+	if (pa) {
+		if (pa->pa_type == MB_GROUP_PA) {
+			/* see comment in ext4_mb_use_group_pa() */
+			spin_lock(&pa->pa_lock);
+			pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+			pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+			pa->pa_free -= ac->ac_b_ex.fe_len;
+			pa->pa_len -= ac->ac_b_ex.fe_len;
+			spin_unlock(&pa->pa_lock);
+
+			/*
+			 * We want to add the pa to the right bucket.
+			 * Remove it from the list and while adding
+			 * make sure the list to which we are adding
+			 * doesn't grow big.
+			 */
+			if (likely(pa->pa_free)) {
+				spin_lock(pa->pa_obj_lock);
+				list_del_rcu(&pa->pa_inode_list);
+				spin_unlock(pa->pa_obj_lock);
+				ext4_mb_add_n_trim(ac);
+			}
+		}
+
+		if (pa->pa_type == MB_INODE_PA) {
+			/*
+			 * treat per-inode prealloc list as a lru list, then try
+			 * to trim the least recently used PA.
+			 */
+			spin_lock(pa->pa_obj_lock);
+			list_move(&pa->pa_inode_list, &ei->i_prealloc_list);
+			spin_unlock(pa->pa_obj_lock);
+		}
+
+		ext4_mb_put_pa(ac, ac->ac_sb, pa);
+	}
+	if (ac->ac_bitmap_page)
+		put_page(ac->ac_bitmap_page);
+	if (ac->ac_buddy_page)
+		put_page(ac->ac_buddy_page);
+	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
+		mutex_unlock(&ac->ac_lg->lg_mutex);
+	ext4_mb_collect_stats(ac);
+	ext4_mb_trim_inode_pa(inode);
+	return 0;
+}
+
+static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
+{
+	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
+	int ret;
+	int freed = 0, busy = 0;
+	int retry = 0;
+
+	trace_ext4_mb_discard_preallocations(sb, needed);
+
+	if (needed == 0)
+		needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
+ repeat:
+	for (i = 0; i < ngroups && needed > 0; i++) {
+		ret = ext4_mb_discard_group_preallocations(sb, i, &busy);
+		freed += ret;
+		needed -= ret;
+		cond_resched();
+	}
+
+	if (needed > 0 && busy && ++retry < 3) {
+		busy = 0;
+		goto repeat;
+	}
+
+	return freed;
+}
+
+static bool ext4_mb_discard_preallocations_should_retry(struct super_block *sb,
+			struct ext4_allocation_context *ac, u64 *seq)
+{
+	int freed;
+	u64 seq_retry = 0;
+	bool ret = false;
+
+	freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
+	if (freed) {
+		ret = true;
+		goto out_dbg;
+	}
+	seq_retry = ext4_get_discard_pa_seq_sum();
+	if (!(ac->ac_flags & EXT4_MB_STRICT_CHECK) || seq_retry != *seq) {
+		ac->ac_flags |= EXT4_MB_STRICT_CHECK;
+		*seq = seq_retry;
+		ret = true;
+	}
+
+out_dbg:
+	mb_debug(sb, "freed %d, retry ? %s\n", freed, ret ? "yes" : "no");
+	return ret;
+}
+
+static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
+				struct ext4_allocation_request *ar, int *errp);
+
+/*
+ * Main entry point into mballoc to allocate blocks
+ * it tries to use preallocation first, then falls back
+ * to usual allocation
+ */
+ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
+				struct ext4_allocation_request *ar, int *errp)
+{
+	struct ext4_allocation_context *ac = NULL;
+	struct ext4_sb_info *sbi;
+	struct super_block *sb;
+	ext4_fsblk_t block = 0;
+	unsigned int inquota = 0;
+	unsigned int reserv_clstrs = 0;
+	int retries = 0;
+	u64 seq;
+
+	might_sleep();
+	sb = ar->inode->i_sb;
+	sbi = EXT4_SB(sb);
+
+	trace_ext4_request_blocks(ar);
+	if (sbi->s_mount_state & EXT4_FC_REPLAY)
+		return ext4_mb_new_blocks_simple(handle, ar, errp);
+
+	/* Allow to use superuser reservation for quota file */
+	if (ext4_is_quota_file(ar->inode))
+		ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
+
+	if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
+		/* Without delayed allocation we need to verify
+		 * there is enough free blocks to do block allocation
+		 * and verify allocation doesn't exceed the quota limits.
+		 */
+		while (ar->len &&
+			ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
+
+			/* let others to free the space */
+			cond_resched();
+			ar->len = ar->len >> 1;
+		}
+		if (!ar->len) {
+			ext4_mb_show_pa(sb);
+			*errp = -ENOSPC;
+			return 0;
+		}
+		reserv_clstrs = ar->len;
+		if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
+			dquot_alloc_block_nofail(ar->inode,
+						 EXT4_C2B(sbi, ar->len));
+		} else {
+			while (ar->len &&
+				dquot_alloc_block(ar->inode,
+						  EXT4_C2B(sbi, ar->len))) {
+
+				ar->flags |= EXT4_MB_HINT_NOPREALLOC;
+				ar->len--;
+			}
+		}
+		inquota = ar->len;
+		if (ar->len == 0) {
+			*errp = -EDQUOT;
+			goto out;
+		}
+	}
+
+	ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
+	if (!ac) {
+		ar->len = 0;
+		*errp = -ENOMEM;
+		goto out;
+	}
+
+	*errp = ext4_mb_initialize_context(ac, ar);
+	if (*errp) {
+		ar->len = 0;
+		goto out;
+	}
+
+	ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
+	seq = this_cpu_read(discard_pa_seq);
+	if (!ext4_mb_use_preallocated(ac)) {
+		ac->ac_op = EXT4_MB_HISTORY_ALLOC;
+		ext4_mb_normalize_request(ac, ar);
+
+		*errp = ext4_mb_pa_alloc(ac);
+		if (*errp)
+			goto errout;
+repeat:
+		/* allocate space in core */
+		*errp = ext4_mb_regular_allocator(ac);
+		/*
+		 * pa allocated above is added to grp->bb_prealloc_list only
+		 * when we were able to allocate some block i.e. when
+		 * ac->ac_status == AC_STATUS_FOUND.
+		 * And error from above mean ac->ac_status != AC_STATUS_FOUND
+		 * So we have to free this pa here itself.
+		 */
+		if (*errp) {
+			ext4_mb_pa_free(ac);
+			ext4_discard_allocated_blocks(ac);
+			goto errout;
+		}
+		if (ac->ac_status == AC_STATUS_FOUND &&
+			ac->ac_o_ex.fe_len >= ac->ac_f_ex.fe_len)
+			ext4_mb_pa_free(ac);
+	}
+	if (likely(ac->ac_status == AC_STATUS_FOUND)) {
+		*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
+		if (*errp) {
+			ext4_discard_allocated_blocks(ac);
+			goto errout;
+		} else {
+			block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+			ar->len = ac->ac_b_ex.fe_len;
+		}
+	} else {
+		if (++retries < 3 &&
+		    ext4_mb_discard_preallocations_should_retry(sb, ac, &seq))
+			goto repeat;
+		/*
+		 * If block allocation fails then the pa allocated above
+		 * needs to be freed here itself.
+		 */
+		ext4_mb_pa_free(ac);
+		*errp = -ENOSPC;
+	}
+
+errout:
+	if (*errp) {
+		ac->ac_b_ex.fe_len = 0;
+		ar->len = 0;
+		ext4_mb_show_ac(ac);
+	}
+	ext4_mb_release_context(ac);
+out:
+	if (ac)
+		kmem_cache_free(ext4_ac_cachep, ac);
+	if (inquota && ar->len < inquota)
+		dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
+	if (!ar->len) {
+		if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
+			/* release all the reserved blocks if non delalloc */
+			percpu_counter_sub(&sbi->s_dirtyclusters_counter,
+						reserv_clstrs);
+	}
+
+	trace_ext4_allocate_blocks(ar, (unsigned long long)block);
+
+	return block;
+}
+
+/*
+ * We can merge two free data extents only if the physical blocks
+ * are contiguous, AND the extents were freed by the same transaction,
+ * AND the blocks are associated with the same group.
+ */
+static void ext4_try_merge_freed_extent(struct ext4_sb_info *sbi,
+					struct ext4_free_data *entry,
+					struct ext4_free_data *new_entry,
+					struct rb_root *entry_rb_root)
+{
+	if ((entry->efd_tid != new_entry->efd_tid) ||
+	    (entry->efd_group != new_entry->efd_group))
+		return;
+	if (entry->efd_start_cluster + entry->efd_count ==
+	    new_entry->efd_start_cluster) {
+		new_entry->efd_start_cluster = entry->efd_start_cluster;
+		new_entry->efd_count += entry->efd_count;
+	} else if (new_entry->efd_start_cluster + new_entry->efd_count ==
+		   entry->efd_start_cluster) {
+		new_entry->efd_count += entry->efd_count;
+	} else
+		return;
+	spin_lock(&sbi->s_md_lock);
+	list_del(&entry->efd_list);
+	spin_unlock(&sbi->s_md_lock);
+	rb_erase(&entry->efd_node, entry_rb_root);
+	kmem_cache_free(ext4_free_data_cachep, entry);
+}
+
+static noinline_for_stack int
+ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
+		      struct ext4_free_data *new_entry)
+{
+	ext4_group_t group = e4b->bd_group;
+	ext4_grpblk_t cluster;
+	ext4_grpblk_t clusters = new_entry->efd_count;
+	struct ext4_free_data *entry;
+	struct ext4_group_info *db = e4b->bd_info;
+	struct super_block *sb = e4b->bd_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct rb_node **n = &db->bb_free_root.rb_node, *node;
+	struct rb_node *parent = NULL, *new_node;
+
+	BUG_ON(!ext4_handle_valid(handle));
+	BUG_ON(e4b->bd_bitmap_page == NULL);
+	BUG_ON(e4b->bd_buddy_page == NULL);
+
+	new_node = &new_entry->efd_node;
+	cluster = new_entry->efd_start_cluster;
+
+	if (!*n) {
+		/* first free block exent. We need to
+		   protect buddy cache from being freed,
+		 * otherwise we'll refresh it from
+		 * on-disk bitmap and lose not-yet-available
+		 * blocks */
+		get_page(e4b->bd_buddy_page);
+		get_page(e4b->bd_bitmap_page);
+	}
+	while (*n) {
+		parent = *n;
+		entry = rb_entry(parent, struct ext4_free_data, efd_node);
+		if (cluster < entry->efd_start_cluster)
+			n = &(*n)->rb_left;
+		else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
+			n = &(*n)->rb_right;
+		else {
+			ext4_grp_locked_error(sb, group, 0,
+				ext4_group_first_block_no(sb, group) +
+				EXT4_C2B(sbi, cluster),
+				"Block already on to-be-freed list");
+			kmem_cache_free(ext4_free_data_cachep, new_entry);
+			return 0;
+		}
+	}
+
+	rb_link_node(new_node, parent, n);
+	rb_insert_color(new_node, &db->bb_free_root);
+
+	/* Now try to see the extent can be merged to left and right */
+	node = rb_prev(new_node);
+	if (node) {
+		entry = rb_entry(node, struct ext4_free_data, efd_node);
+		ext4_try_merge_freed_extent(sbi, entry, new_entry,
+					    &(db->bb_free_root));
+	}
+
+	node = rb_next(new_node);
+	if (node) {
+		entry = rb_entry(node, struct ext4_free_data, efd_node);
+		ext4_try_merge_freed_extent(sbi, entry, new_entry,
+					    &(db->bb_free_root));
+	}
+
+	spin_lock(&sbi->s_md_lock);
+	list_add_tail(&new_entry->efd_list, &sbi->s_freed_data_list);
+	sbi->s_mb_free_pending += clusters;
+	spin_unlock(&sbi->s_md_lock);
+	return 0;
+}
+
+/*
+ * Simple allocator for Ext4 fast commit replay path. It searches for blocks
+ * linearly starting at the goal block and also excludes the blocks which
+ * are going to be in use after fast commit replay.
+ */
+static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
+				struct ext4_allocation_request *ar, int *errp)
+{
+	struct buffer_head *bitmap_bh;
+	struct super_block *sb = ar->inode->i_sb;
+	ext4_group_t group;
+	ext4_grpblk_t blkoff;
+	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
+	ext4_grpblk_t i = 0;
+	ext4_fsblk_t goal, block;
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	goal = ar->goal;
+	if (goal < le32_to_cpu(es->s_first_data_block) ||
+			goal >= ext4_blocks_count(es))
+		goal = le32_to_cpu(es->s_first_data_block);
+
+	ar->len = 0;
+	ext4_get_group_no_and_offset(sb, goal, &group, &blkoff);
+	for (; group < ext4_get_groups_count(sb); group++) {
+		bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (IS_ERR(bitmap_bh)) {
+			*errp = PTR_ERR(bitmap_bh);
+			pr_warn("Failed to read block bitmap\n");
+			return 0;
+		}
+
+		ext4_get_group_no_and_offset(sb,
+			max(ext4_group_first_block_no(sb, group), goal),
+			NULL, &blkoff);
+		while (1) {
+			i = mb_find_next_zero_bit(bitmap_bh->b_data, max,
+						blkoff);
+			if (i >= max)
+				break;
+			if (ext4_fc_replay_check_excluded(sb,
+				ext4_group_first_block_no(sb, group) + i)) {
+				blkoff = i + 1;
+			} else
+				break;
+		}
+		brelse(bitmap_bh);
+		if (i < max)
+			break;
+	}
+
+	if (group >= ext4_get_groups_count(sb) || i >= max) {
+		*errp = -ENOSPC;
+		return 0;
+	}
+
+	block = ext4_group_first_block_no(sb, group) + i;
+	ext4_mb_mark_bb(sb, block, 1, 1);
+	ar->len = 1;
+
+	return block;
+}
+
+static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
+					unsigned long count)
+{
+	struct buffer_head *bitmap_bh;
+	struct super_block *sb = inode->i_sb;
+	struct ext4_group_desc *gdp;
+	struct buffer_head *gdp_bh;
+	ext4_group_t group;
+	ext4_grpblk_t blkoff;
+	int already_freed = 0, err, i;
+
+	ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
+	bitmap_bh = ext4_read_block_bitmap(sb, group);
+	if (IS_ERR(bitmap_bh)) {
+		err = PTR_ERR(bitmap_bh);
+		pr_warn("Failed to read block bitmap\n");
+		return;
+	}
+	gdp = ext4_get_group_desc(sb, group, &gdp_bh);
+	if (!gdp)
+		return;
+
+	for (i = 0; i < count; i++) {
+		if (!mb_test_bit(blkoff + i, bitmap_bh->b_data))
+			already_freed++;
+	}
+	mb_clear_bits(bitmap_bh->b_data, blkoff, count);
+	err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
+	if (err)
+		return;
+	ext4_free_group_clusters_set(
+		sb, gdp, ext4_free_group_clusters(sb, gdp) +
+		count - already_freed);
+	ext4_block_bitmap_csum_set(sb, group, gdp, bitmap_bh);
+	ext4_group_desc_csum_set(sb, group, gdp);
+	ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
+	sync_dirty_buffer(bitmap_bh);
+	sync_dirty_buffer(gdp_bh);
+	brelse(bitmap_bh);
+}
+
+/**
+ * ext4_mb_clear_bb() -- helper function for freeing blocks.
+ *			Used by ext4_free_blocks()
+ * @handle:		handle for this transaction
+ * @inode:		inode
+ * @bh:			optional buffer of the block to be freed
+ * @block:		starting physical block to be freed
+ * @count:		number of blocks to be freed
+ * @flags:		flags used by ext4_free_blocks
+ */
+static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode,
+			       ext4_fsblk_t block, unsigned long count,
+			       int flags)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct super_block *sb = inode->i_sb;
+	struct ext4_group_desc *gdp;
+	struct ext4_group_info *grp;
+	unsigned int overflow;
+	ext4_grpblk_t bit;
+	struct buffer_head *gd_bh;
+	ext4_group_t block_group;
+	struct ext4_sb_info *sbi;
+	struct ext4_buddy e4b;
+	unsigned int count_clusters;
+	int err = 0;
+	int ret;
+
+	sbi = EXT4_SB(sb);
+
+	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+	    !ext4_inode_block_valid(inode, block, count)) {
+		ext4_error(sb, "Freeing blocks in system zone - "
+			   "Block = %llu, count = %lu", block, count);
+		/* err = 0. ext4_std_error should be a no op */
+		goto error_return;
+	}
+	flags |= EXT4_FREE_BLOCKS_VALIDATED;
+
+do_more:
+	overflow = 0;
+	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
+
+	grp = ext4_get_group_info(sb, block_group);
+	if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
+		return;
+
+	/*
+	 * Check to see if we are freeing blocks across a group
+	 * boundary.
+	 */
+	if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
+		overflow = EXT4_C2B(sbi, bit) + count -
+			EXT4_BLOCKS_PER_GROUP(sb);
+		count -= overflow;
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+	}
+	count_clusters = EXT4_NUM_B2C(sbi, count);
+	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
+	if (IS_ERR(bitmap_bh)) {
+		err = PTR_ERR(bitmap_bh);
+		bitmap_bh = NULL;
+		goto error_return;
+	}
+	gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
+	if (!gdp) {
+		err = -EIO;
+		goto error_return;
+	}
+
+	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+	    !ext4_inode_block_valid(inode, block, count)) {
+		ext4_error(sb, "Freeing blocks in system zone - "
+			   "Block = %llu, count = %lu", block, count);
+		/* err = 0. ext4_std_error should be a no op */
+		goto error_return;
+	}
+
+	BUFFER_TRACE(bitmap_bh, "getting write access");
+	err = ext4_journal_get_write_access(handle, bitmap_bh);
+	if (err)
+		goto error_return;
+
+	/*
+	 * We are about to modify some metadata.  Call the journal APIs
+	 * to unshare ->b_data if a currently-committing transaction is
+	 * using it
+	 */
+	BUFFER_TRACE(gd_bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, gd_bh);
+	if (err)
+		goto error_return;
+#ifdef AGGRESSIVE_CHECK
+	{
+		int i;
+		for (i = 0; i < count_clusters; i++)
+			BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
+	}
+#endif
+	trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
+
+	/* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */
+	err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b,
+				     GFP_NOFS|__GFP_NOFAIL);
+	if (err)
+		goto error_return;
+
+	/*
+	 * We need to make sure we don't reuse the freed block until after the
+	 * transaction is committed. We make an exception if the inode is to be
+	 * written in writeback mode since writeback mode has weak data
+	 * consistency guarantees.
+	 */
+	if (ext4_handle_valid(handle) &&
+	    ((flags & EXT4_FREE_BLOCKS_METADATA) ||
+	     !ext4_should_writeback_data(inode))) {
+		struct ext4_free_data *new_entry;
+		/*
+		 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
+		 * to fail.
+		 */
+		new_entry = kmem_cache_alloc(ext4_free_data_cachep,
+				GFP_NOFS|__GFP_NOFAIL);
+		new_entry->efd_start_cluster = bit;
+		new_entry->efd_group = block_group;
+		new_entry->efd_count = count_clusters;
+		new_entry->efd_tid = handle->h_transaction->t_tid;
+
+		ext4_lock_group(sb, block_group);
+		mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
+		ext4_mb_free_metadata(handle, &e4b, new_entry);
+	} else {
+		/* need to update group_info->bb_free and bitmap
+		 * with group lock held. generate_buddy look at
+		 * them with group lock_held
+		 */
+		if (test_opt(sb, DISCARD)) {
+			err = ext4_issue_discard(sb, block_group, bit,
+						 count_clusters, NULL);
+			if (err && err != -EOPNOTSUPP)
+				ext4_msg(sb, KERN_WARNING, "discard request in"
+					 " group:%u block:%d count:%lu failed"
+					 " with %d", block_group, bit, count,
+					 err);
+		} else
+			EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
+
+		ext4_lock_group(sb, block_group);
+		mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
+		mb_free_blocks(inode, &e4b, bit, count_clusters);
+	}
+
+	ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
+	ext4_free_group_clusters_set(sb, gdp, ret);
+	ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
+	ext4_group_desc_csum_set(sb, block_group, gdp);
+	ext4_unlock_group(sb, block_group);
+
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
+		atomic64_add(count_clusters,
+			     &sbi_array_rcu_deref(sbi, s_flex_groups,
+						  flex_group)->free_clusters);
+	}
+
+	/*
+	 * on a bigalloc file system, defer the s_freeclusters_counter
+	 * update to the caller (ext4_remove_space and friends) so they
+	 * can determine if a cluster freed here should be rereserved
+	 */
+	if (!(flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)) {
+		if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
+			dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
+		percpu_counter_add(&sbi->s_freeclusters_counter,
+				   count_clusters);
+	}
+
+	ext4_mb_unload_buddy(&e4b);
+
+	/* We dirtied the bitmap block */
+	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
+	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+
+	/* And the group descriptor block */
+	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
+	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
+	if (!err)
+		err = ret;
+
+	if (overflow && !err) {
+		block += count;
+		count = overflow;
+		put_bh(bitmap_bh);
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+		goto do_more;
+	}
+error_return:
+	brelse(bitmap_bh);
+	ext4_std_error(sb, err);
+	return;
+}
+
+/**
+ * ext4_free_blocks() -- Free given blocks and update quota
+ * @handle:		handle for this transaction
+ * @inode:		inode
+ * @bh:			optional buffer of the block to be freed
+ * @block:		starting physical block to be freed
+ * @count:		number of blocks to be freed
+ * @flags:		flags used by ext4_free_blocks
+ */
+void ext4_free_blocks(handle_t *handle, struct inode *inode,
+		      struct buffer_head *bh, ext4_fsblk_t block,
+		      unsigned long count, int flags)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned int overflow;
+	struct ext4_sb_info *sbi;
+
+	sbi = EXT4_SB(sb);
+
+	if (bh) {
+		if (block)
+			BUG_ON(block != bh->b_blocknr);
+		else
+			block = bh->b_blocknr;
+	}
+
+	if (sbi->s_mount_state & EXT4_FC_REPLAY) {
+		ext4_free_blocks_simple(inode, block, EXT4_NUM_B2C(sbi, count));
+		return;
+	}
+
+	might_sleep();
+
+	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+	    !ext4_inode_block_valid(inode, block, count)) {
+		ext4_error(sb, "Freeing blocks not in datazone - "
+			   "block = %llu, count = %lu", block, count);
+		return;
+	}
+	flags |= EXT4_FREE_BLOCKS_VALIDATED;
+
+	ext4_debug("freeing block %llu\n", block);
+	trace_ext4_free_blocks(inode, block, count, flags);
+
+	if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
+		BUG_ON(count > 1);
+
+		ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
+			    inode, bh, block);
+	}
+
+	/*
+	 * If the extent to be freed does not begin on a cluster
+	 * boundary, we need to deal with partial clusters at the
+	 * beginning and end of the extent.  Normally we will free
+	 * blocks at the beginning or the end unless we are explicitly
+	 * requested to avoid doing so.
+	 */
+	overflow = EXT4_PBLK_COFF(sbi, block);
+	if (overflow) {
+		if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
+			overflow = sbi->s_cluster_ratio - overflow;
+			block += overflow;
+			if (count > overflow)
+				count -= overflow;
+			else
+				return;
+		} else {
+			block -= overflow;
+			count += overflow;
+		}
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+	}
+	overflow = EXT4_LBLK_COFF(sbi, count);
+	if (overflow) {
+		if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
+			if (count > overflow)
+				count -= overflow;
+			else
+				return;
+		} else
+			count += sbi->s_cluster_ratio - overflow;
+		/* The range changed so it's no longer validated */
+		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+	}
+
+	if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
+		int i;
+		int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
+
+		for (i = 0; i < count; i++) {
+			cond_resched();
+			if (is_metadata)
+				bh = sb_find_get_block(inode->i_sb, block + i);
+			ext4_forget(handle, is_metadata, inode, bh, block + i);
+		}
+	}
+
+	ext4_mb_clear_bb(handle, inode, block, count, flags);
+	return;
+}
+
+/**
+ * ext4_group_add_blocks() -- Add given blocks to an existing group
+ * @handle:			handle to this transaction
+ * @sb:				super block
+ * @block:			start physical block to add to the block group
+ * @count:			number of blocks to free
+ *
+ * This marks the blocks as free in the bitmap and buddy.
+ */
+int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
+			 ext4_fsblk_t block, unsigned long count)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *gd_bh;
+	ext4_group_t block_group;
+	ext4_grpblk_t bit;
+	unsigned int i;
+	struct ext4_group_desc *desc;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_buddy e4b;
+	int err = 0, ret, free_clusters_count;
+	ext4_grpblk_t clusters_freed;
+	ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block);
+	ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1);
+	unsigned long cluster_count = last_cluster - first_cluster + 1;
+
+	ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
+
+	if (count == 0)
+		return 0;
+
+	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
+	/*
+	 * Check to see if we are freeing blocks across a group
+	 * boundary.
+	 */
+	if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) {
+		ext4_warning(sb, "too many blocks added to group %u",
+			     block_group);
+		err = -EINVAL;
+		goto error_return;
+	}
+
+	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
+	if (IS_ERR(bitmap_bh)) {
+		err = PTR_ERR(bitmap_bh);
+		bitmap_bh = NULL;
+		goto error_return;
+	}
+
+	desc = ext4_get_group_desc(sb, block_group, &gd_bh);
+	if (!desc) {
+		err = -EIO;
+		goto error_return;
+	}
+
+	if (!ext4_sb_block_valid(sb, NULL, block, count)) {
+		ext4_error(sb, "Adding blocks in system zones - "
+			   "Block = %llu, count = %lu",
+			   block, count);
+		err = -EINVAL;
+		goto error_return;
+	}
+
+	BUFFER_TRACE(bitmap_bh, "getting write access");
+	err = ext4_journal_get_write_access(handle, bitmap_bh);
+	if (err)
+		goto error_return;
+
+	/*
+	 * We are about to modify some metadata.  Call the journal APIs
+	 * to unshare ->b_data if a currently-committing transaction is
+	 * using it
+	 */
+	BUFFER_TRACE(gd_bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, gd_bh);
+	if (err)
+		goto error_return;
+
+	for (i = 0, clusters_freed = 0; i < cluster_count; i++) {
+		BUFFER_TRACE(bitmap_bh, "clear bit");
+		if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
+			ext4_error(sb, "bit already cleared for block %llu",
+				   (ext4_fsblk_t)(block + i));
+			BUFFER_TRACE(bitmap_bh, "bit already cleared");
+		} else {
+			clusters_freed++;
+		}
+	}
+
+	err = ext4_mb_load_buddy(sb, block_group, &e4b);
+	if (err)
+		goto error_return;
+
+	/*
+	 * need to update group_info->bb_free and bitmap
+	 * with group lock held. generate_buddy look at
+	 * them with group lock_held
+	 */
+	ext4_lock_group(sb, block_group);
+	mb_clear_bits(bitmap_bh->b_data, bit, cluster_count);
+	mb_free_blocks(NULL, &e4b, bit, cluster_count);
+	free_clusters_count = clusters_freed +
+		ext4_free_group_clusters(sb, desc);
+	ext4_free_group_clusters_set(sb, desc, free_clusters_count);
+	ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh);
+	ext4_group_desc_csum_set(sb, block_group, desc);
+	ext4_unlock_group(sb, block_group);
+	percpu_counter_add(&sbi->s_freeclusters_counter,
+			   clusters_freed);
+
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
+		atomic64_add(clusters_freed,
+			     &sbi_array_rcu_deref(sbi, s_flex_groups,
+						  flex_group)->free_clusters);
+	}
+
+	ext4_mb_unload_buddy(&e4b);
+
+	/* We dirtied the bitmap block */
+	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
+	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+
+	/* And the group descriptor block */
+	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
+	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
+	if (!err)
+		err = ret;
+
+error_return:
+	brelse(bitmap_bh);
+	ext4_std_error(sb, err);
+	return err;
+}
+
+/**
+ * ext4_trim_extent -- function to TRIM one single free extent in the group
+ * @sb:		super block for the file system
+ * @start:	starting block of the free extent in the alloc. group
+ * @count:	number of blocks to TRIM
+ * @e4b:	ext4 buddy for the group
+ *
+ * Trim "count" blocks starting at "start" in the "group". To assure that no
+ * one will allocate those blocks, mark it as used in buddy bitmap. This must
+ * be called with under the group lock.
+ */
+static int ext4_trim_extent(struct super_block *sb,
+		int start, int count, struct ext4_buddy *e4b)
+__releases(bitlock)
+__acquires(bitlock)
+{
+	struct ext4_free_extent ex;
+	ext4_group_t group = e4b->bd_group;
+	int ret = 0;
+
+	trace_ext4_trim_extent(sb, group, start, count);
+
+	assert_spin_locked(ext4_group_lock_ptr(sb, group));
+
+	ex.fe_start = start;
+	ex.fe_group = group;
+	ex.fe_len = count;
+
+	/*
+	 * Mark blocks used, so no one can reuse them while
+	 * being trimmed.
+	 */
+	mb_mark_used(e4b, &ex);
+	ext4_unlock_group(sb, group);
+	ret = ext4_issue_discard(sb, group, start, count, NULL);
+	ext4_lock_group(sb, group);
+	mb_free_blocks(NULL, e4b, start, ex.fe_len);
+	return ret;
+}
+
+static ext4_grpblk_t ext4_last_grp_cluster(struct super_block *sb,
+					   ext4_group_t grp)
+{
+	if (grp < ext4_get_groups_count(sb))
+		return EXT4_CLUSTERS_PER_GROUP(sb) - 1;
+	return (ext4_blocks_count(EXT4_SB(sb)->s_es) -
+		ext4_group_first_block_no(sb, grp) - 1) >>
+					EXT4_CLUSTER_BITS(sb);
+}
+
+static bool ext4_trim_interrupted(void)
+{
+	return fatal_signal_pending(current) || freezing(current);
+}
+
+static int ext4_try_to_trim_range(struct super_block *sb,
+		struct ext4_buddy *e4b, ext4_grpblk_t start,
+		ext4_grpblk_t max, ext4_grpblk_t minblocks)
+{
+	ext4_grpblk_t next, count, free_count;
+	bool set_trimmed = false;
+	void *bitmap;
+
+	bitmap = e4b->bd_bitmap;
+	if (start == 0 && max >= ext4_last_grp_cluster(sb, e4b->bd_group))
+		set_trimmed = true;
+	start = max(e4b->bd_info->bb_first_free, start);
+	count = 0;
+	free_count = 0;
+
+	while (start <= max) {
+		start = mb_find_next_zero_bit(bitmap, max + 1, start);
+		if (start > max)
+			break;
+		next = mb_find_next_bit(bitmap, max + 1, start);
+
+		if ((next - start) >= minblocks) {
+			int ret = ext4_trim_extent(sb, start, next - start, e4b);
+
+			if (ret && ret != -EOPNOTSUPP)
+				return count;
+			count += next - start;
+		}
+		free_count += next - start;
+		start = next + 1;
+
+		if (ext4_trim_interrupted())
+			return count;
+
+		if (need_resched()) {
+			ext4_unlock_group(sb, e4b->bd_group);
+			cond_resched();
+			ext4_lock_group(sb, e4b->bd_group);
+		}
+
+		if ((e4b->bd_info->bb_free - free_count) < minblocks)
+			break;
+	}
+
+	if (set_trimmed)
+		EXT4_MB_GRP_SET_TRIMMED(e4b->bd_info);
+
+	return count;
+}
+
+/**
+ * ext4_trim_all_free -- function to trim all free space in alloc. group
+ * @sb:			super block for file system
+ * @group:		group to be trimmed
+ * @start:		first group block to examine
+ * @max:		last group block to examine
+ * @minblocks:		minimum extent block count
+ *
+ * ext4_trim_all_free walks through group's buddy bitmap searching for free
+ * extents. When the free block is found, ext4_trim_extent is called to TRIM
+ * the extent.
+ *
+ *
+ * ext4_trim_all_free walks through group's block bitmap searching for free
+ * extents. When the free extent is found, mark it as used in group buddy
+ * bitmap. Then issue a TRIM command on this extent and free the extent in
+ * the group buddy bitmap. This is done until whole group is scanned.
+ */
+static ext4_grpblk_t
+ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
+		   ext4_grpblk_t start, ext4_grpblk_t max,
+		   ext4_grpblk_t minblocks)
+{
+	struct ext4_buddy e4b;
+	int ret;
+
+	trace_ext4_trim_all_free(sb, group, start, max);
+
+	ret = ext4_mb_load_buddy(sb, group, &e4b);
+	if (ret) {
+		ext4_warning(sb, "Error %d loading buddy information for %u",
+			     ret, group);
+		return ret;
+	}
+
+	ext4_lock_group(sb, group);
+
+	if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
+	    minblocks < EXT4_SB(sb)->s_last_trim_minblks)
+		ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
+	else
+		ret = 0;
+
+	ext4_unlock_group(sb, group);
+	ext4_mb_unload_buddy(&e4b);
+
+	ext4_debug("trimmed %d blocks in the group %d\n",
+		ret, group);
+
+	return ret;
+}
+
+/**
+ * ext4_trim_fs() -- trim ioctl handle function
+ * @sb:			superblock for filesystem
+ * @range:		fstrim_range structure
+ *
+ * start:	First Byte to trim
+ * len:		number of Bytes to trim from start
+ * minlen:	minimum extent length in Bytes
+ * ext4_trim_fs goes through all allocation groups containing Bytes from
+ * start to start+len. For each such a group ext4_trim_all_free function
+ * is invoked to trim all free space.
+ */
+int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
+{
+	struct request_queue *q = bdev_get_queue(sb->s_bdev);
+	struct ext4_group_info *grp;
+	ext4_group_t group, first_group, last_group;
+	ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
+	uint64_t start, end, minlen, trimmed = 0;
+	ext4_fsblk_t first_data_blk =
+			le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
+	ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
+	int ret = 0;
+
+	start = range->start >> sb->s_blocksize_bits;
+	end = start + (range->len >> sb->s_blocksize_bits) - 1;
+	minlen = EXT4_NUM_B2C(EXT4_SB(sb),
+			      range->minlen >> sb->s_blocksize_bits);
+
+	if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
+	    start >= max_blks ||
+	    range->len < sb->s_blocksize)
+		return -EINVAL;
+	/* No point to try to trim less than discard granularity */
+	if (range->minlen < q->limits.discard_granularity) {
+		minlen = EXT4_NUM_B2C(EXT4_SB(sb),
+			q->limits.discard_granularity >> sb->s_blocksize_bits);
+		if (minlen > EXT4_CLUSTERS_PER_GROUP(sb))
+			goto out;
+	}
+	if (end >= max_blks - 1)
+		end = max_blks - 1;
+	if (end <= first_data_blk)
+		goto out;
+	if (start < first_data_blk)
+		start = first_data_blk;
+
+	/* Determine first and last group to examine based on start and end */
+	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
+				     &first_group, &first_cluster);
+	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
+				     &last_group, &last_cluster);
+
+	/* end now represents the last cluster to discard in this group */
+	end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
+
+	for (group = first_group; group <= last_group; group++) {
+		if (ext4_trim_interrupted())
+			break;
+		grp = ext4_get_group_info(sb, group);
+		if (!grp)
+			continue;
+		/* We only do this if the grp has never been initialized */
+		if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
+			ret = ext4_mb_init_group(sb, group, GFP_NOFS);
+			if (ret)
+				break;
+		}
+
+		/*
+		 * For all the groups except the last one, last cluster will
+		 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
+		 * change it for the last group, note that last_cluster is
+		 * already computed earlier by ext4_get_group_no_and_offset()
+		 */
+		if (group == last_group)
+			end = last_cluster;
+		if (grp->bb_free >= minlen) {
+			cnt = ext4_trim_all_free(sb, group, first_cluster,
+						 end, minlen);
+			if (cnt < 0) {
+				ret = cnt;
+				break;
+			}
+			trimmed += cnt;
+		}
+
+		/*
+		 * For every group except the first one, we are sure
+		 * that the first cluster to discard will be cluster #0.
+		 */
+		first_cluster = 0;
+	}
+
+	if (!ret)
+		EXT4_SB(sb)->s_last_trim_minblks = minlen;
+
+out:
+	range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
+	return ret;
+}
+
+/* Iterate all the free extents in the group. */
+int
+ext4_mballoc_query_range(
+	struct super_block		*sb,
+	ext4_group_t			group,
+	ext4_grpblk_t			start,
+	ext4_grpblk_t			end,
+	ext4_mballoc_query_range_fn	formatter,
+	void				*priv)
+{
+	void				*bitmap;
+	ext4_grpblk_t			next;
+	struct ext4_buddy		e4b;
+	int				error;
+
+	error = ext4_mb_load_buddy(sb, group, &e4b);
+	if (error)
+		return error;
+	bitmap = e4b.bd_bitmap;
+
+	ext4_lock_group(sb, group);
+
+	start = max(e4b.bd_info->bb_first_free, start);
+	if (end >= EXT4_CLUSTERS_PER_GROUP(sb))
+		end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
+
+	while (start <= end) {
+		start = mb_find_next_zero_bit(bitmap, end + 1, start);
+		if (start > end)
+			break;
+		next = mb_find_next_bit(bitmap, end + 1, start);
+
+		ext4_unlock_group(sb, group);
+		error = formatter(sb, group, start, next - start, priv);
+		if (error)
+			goto out_unload;
+		ext4_lock_group(sb, group);
+
+		start = next + 1;
+	}
+
+	ext4_unlock_group(sb, group);
+out_unload:
+	ext4_mb_unload_buddy(&e4b);
+
+	return error;
+}
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
new file mode 100644
index 000000000..1e9c40218
--- /dev/null
+++ b/fs/ext4/mballoc.h
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  fs/ext4/mballoc.h
+ *
+ *  Written by: Alex Tomas <alex@clusterfs.com>
+ *
+ */
+#ifndef _EXT4_MBALLOC_H
+#define _EXT4_MBALLOC_H
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/module.h>
+#include <linux/swap.h>
+#include <linux/proc_fs.h>
+#include <linux/pagemap.h>
+#include <linux/seq_file.h>
+#include <linux/blkdev.h>
+#include <linux/mutex.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+
+/*
+ * mb_debug() dynamic printk msgs could be used to debug mballoc code.
+ */
+#ifdef CONFIG_EXT4_DEBUG
+#define mb_debug(sb, fmt, ...)						\
+	pr_debug("[%s/%d] EXT4-fs (%s): (%s, %d): %s: " fmt,		\
+		current->comm, task_pid_nr(current), sb->s_id,		\
+	       __FILE__, __LINE__, __func__, ##__VA_ARGS__)
+#else
+#define mb_debug(sb, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+#endif
+
+#define EXT4_MB_HISTORY_ALLOC		1	/* allocation */
+#define EXT4_MB_HISTORY_PREALLOC	2	/* preallocated blocks used */
+
+/*
+ * How long mballoc can look for a best extent (in found extents)
+ */
+#define MB_DEFAULT_MAX_TO_SCAN		200
+
+/*
+ * How long mballoc must look for a best extent
+ */
+#define MB_DEFAULT_MIN_TO_SCAN		10
+
+/*
+ * with 'ext4_mb_stats' allocator will collect stats that will be
+ * shown at umount. The collecting costs though!
+ */
+#define MB_DEFAULT_STATS		0
+
+/*
+ * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
+ * by the stream allocator, which purpose is to pack requests
+ * as close each to other as possible to produce smooth I/O traffic
+ * We use locality group prealloc space for stream request.
+ * We can tune the same via /proc/fs/ext4/<partition>/stream_req
+ */
+#define MB_DEFAULT_STREAM_THRESHOLD	16	/* 64K */
+
+/*
+ * for which requests use 2^N search using buddies
+ */
+#define MB_DEFAULT_ORDER2_REQS		2
+
+/*
+ * default group prealloc size 512 blocks
+ */
+#define MB_DEFAULT_GROUP_PREALLOC	512
+
+/*
+ * maximum length of inode prealloc list
+ */
+#define MB_DEFAULT_MAX_INODE_PREALLOC	512
+
+struct ext4_free_data {
+	/* this links the free block information from sb_info */
+	struct list_head		efd_list;
+
+	/* this links the free block information from group_info */
+	struct rb_node			efd_node;
+
+	/* group which free block extent belongs */
+	ext4_group_t			efd_group;
+
+	/* free block extent */
+	ext4_grpblk_t			efd_start_cluster;
+	ext4_grpblk_t			efd_count;
+
+	/* transaction which freed this extent */
+	tid_t				efd_tid;
+};
+
+struct ext4_prealloc_space {
+	struct list_head	pa_inode_list;
+	struct list_head	pa_group_list;
+	union {
+		struct list_head pa_tmp_list;
+		struct rcu_head	pa_rcu;
+	} u;
+	spinlock_t		pa_lock;
+	atomic_t		pa_count;
+	unsigned		pa_deleted;
+	ext4_fsblk_t		pa_pstart;	/* phys. block */
+	ext4_lblk_t		pa_lstart;	/* log. block */
+	ext4_grpblk_t		pa_len;		/* len of preallocated chunk */
+	ext4_grpblk_t		pa_free;	/* how many blocks are free */
+	unsigned short		pa_type;	/* pa type. inode or group */
+	spinlock_t		*pa_obj_lock;
+	struct inode		*pa_inode;	/* hack, for history only */
+};
+
+enum {
+	MB_INODE_PA = 0,
+	MB_GROUP_PA = 1
+};
+
+struct ext4_free_extent {
+	ext4_lblk_t fe_logical;
+	ext4_grpblk_t fe_start;	/* In cluster units */
+	ext4_group_t fe_group;
+	ext4_grpblk_t fe_len;	/* In cluster units */
+};
+
+/*
+ * Locality group:
+ *   we try to group all related changes together
+ *   so that writeback can flush/allocate them together as well
+ *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
+ *   (512). We store prealloc space into the hash based on the pa_free blocks
+ *   order value.ie, fls(pa_free)-1;
+ */
+#define PREALLOC_TB_SIZE 10
+struct ext4_locality_group {
+	/* for allocator */
+	/* to serialize allocates */
+	struct mutex		lg_mutex;
+	/* list of preallocations */
+	struct list_head	lg_prealloc_list[PREALLOC_TB_SIZE];
+	spinlock_t		lg_prealloc_lock;
+};
+
+struct ext4_allocation_context {
+	struct inode *ac_inode;
+	struct super_block *ac_sb;
+
+	/* original request */
+	struct ext4_free_extent ac_o_ex;
+
+	/* goal request (normalized ac_o_ex) */
+	struct ext4_free_extent ac_g_ex;
+
+	/* the best found extent */
+	struct ext4_free_extent ac_b_ex;
+
+	/* copy of the best found extent taken before preallocation efforts */
+	struct ext4_free_extent ac_f_ex;
+
+	__u16 ac_groups_scanned;
+	__u16 ac_found;
+	__u16 ac_tail;
+	__u16 ac_buddy;
+	__u16 ac_flags;		/* allocation hints */
+	__u8 ac_status;
+	__u8 ac_criteria;
+	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
+				 * N > 0, the field stores N, otherwise 0 */
+	__u8 ac_op;		/* operation, for history only */
+	struct page *ac_bitmap_page;
+	struct page *ac_buddy_page;
+	struct ext4_prealloc_space *ac_pa;
+	struct ext4_locality_group *ac_lg;
+};
+
+#define AC_STATUS_CONTINUE	1
+#define AC_STATUS_FOUND		2
+#define AC_STATUS_BREAK		3
+
+struct ext4_buddy {
+	struct page *bd_buddy_page;
+	void *bd_buddy;
+	struct page *bd_bitmap_page;
+	void *bd_bitmap;
+	struct ext4_group_info *bd_info;
+	struct super_block *bd_sb;
+	__u16 bd_blkbits;
+	ext4_group_t bd_group;
+};
+
+static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
+					struct ext4_free_extent *fex)
+{
+	return ext4_group_first_block_no(sb, fex->fe_group) +
+		(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
+}
+
+static inline loff_t extent_logical_end(struct ext4_sb_info *sbi,
+					struct ext4_free_extent *fex)
+{
+	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
+	return (loff_t)fex->fe_logical + EXT4_C2B(sbi, fex->fe_len);
+}
+
+static inline loff_t pa_logical_end(struct ext4_sb_info *sbi,
+				    struct ext4_prealloc_space *pa)
+{
+	/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
+	return (loff_t)pa->pa_lstart + EXT4_C2B(sbi, pa->pa_len);
+}
+
+typedef int (*ext4_mballoc_query_range_fn)(
+	struct super_block		*sb,
+	ext4_group_t			agno,
+	ext4_grpblk_t			start,
+	ext4_grpblk_t			len,
+	void				*priv);
+
+int
+ext4_mballoc_query_range(
+	struct super_block		*sb,
+	ext4_group_t			agno,
+	ext4_grpblk_t			start,
+	ext4_grpblk_t			end,
+	ext4_mballoc_query_range_fn	formatter,
+	void				*priv);
+
+#endif
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
new file mode 100644
index 000000000..b0ea64645
--- /dev/null
+++ b/fs/ext4/migrate.c
@@ -0,0 +1,671 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright IBM Corporation, 2007
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ */
+
+#include <linux/slab.h>
+#include "ext4_jbd2.h"
+#include "ext4_extents.h"
+
+/*
+ * The contiguous blocks details which can be
+ * represented by a single extent
+ */
+struct migrate_struct {
+	ext4_lblk_t first_block, last_block, curr_block;
+	ext4_fsblk_t first_pblock, last_pblock;
+};
+
+static int finish_range(handle_t *handle, struct inode *inode,
+				struct migrate_struct *lb)
+
+{
+	int retval = 0, needed;
+	struct ext4_extent newext;
+	struct ext4_ext_path *path;
+	if (lb->first_pblock == 0)
+		return 0;
+
+	/* Add the extent to temp inode*/
+	newext.ee_block = cpu_to_le32(lb->first_block);
+	newext.ee_len   = cpu_to_le16(lb->last_block - lb->first_block + 1);
+	ext4_ext_store_pblock(&newext, lb->first_pblock);
+	/* Locking only for convenience since we are operating on temp inode */
+	down_write(&EXT4_I(inode)->i_data_sem);
+	path = ext4_find_extent(inode, lb->first_block, NULL, 0);
+	if (IS_ERR(path)) {
+		retval = PTR_ERR(path);
+		path = NULL;
+		goto err_out;
+	}
+
+	/*
+	 * Calculate the credit needed to inserting this extent
+	 * Since we are doing this in loop we may accumulate extra
+	 * credit. But below we try to not accumulate too much
+	 * of them by restarting the journal.
+	 */
+	needed = ext4_ext_calc_credits_for_single_extent(inode,
+		    lb->last_block - lb->first_block + 1, path);
+
+	retval = ext4_datasem_ensure_credits(handle, inode, needed, needed, 0);
+	if (retval < 0)
+		goto err_out;
+	retval = ext4_ext_insert_extent(handle, inode, &path, &newext, 0);
+err_out:
+	up_write((&EXT4_I(inode)->i_data_sem));
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	lb->first_pblock = 0;
+	return retval;
+}
+
+static int update_extent_range(handle_t *handle, struct inode *inode,
+			       ext4_fsblk_t pblock, struct migrate_struct *lb)
+{
+	int retval;
+	/*
+	 * See if we can add on to the existing range (if it exists)
+	 */
+	if (lb->first_pblock &&
+		(lb->last_pblock+1 == pblock) &&
+		(lb->last_block+1 == lb->curr_block)) {
+		lb->last_pblock = pblock;
+		lb->last_block = lb->curr_block;
+		lb->curr_block++;
+		return 0;
+	}
+	/*
+	 * Start a new range.
+	 */
+	retval = finish_range(handle, inode, lb);
+	lb->first_pblock = lb->last_pblock = pblock;
+	lb->first_block = lb->last_block = lb->curr_block;
+	lb->curr_block++;
+	return retval;
+}
+
+static int update_ind_extent_range(handle_t *handle, struct inode *inode,
+				   ext4_fsblk_t pblock,
+				   struct migrate_struct *lb)
+{
+	struct buffer_head *bh;
+	__le32 *i_data;
+	int i, retval = 0;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = ext4_sb_bread(inode->i_sb, pblock, 0);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	i_data = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (i_data[i]) {
+			retval = update_extent_range(handle, inode,
+						le32_to_cpu(i_data[i]), lb);
+			if (retval)
+				break;
+		} else {
+			lb->curr_block++;
+		}
+	}
+	put_bh(bh);
+	return retval;
+
+}
+
+static int update_dind_extent_range(handle_t *handle, struct inode *inode,
+				    ext4_fsblk_t pblock,
+				    struct migrate_struct *lb)
+{
+	struct buffer_head *bh;
+	__le32 *i_data;
+	int i, retval = 0;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = ext4_sb_bread(inode->i_sb, pblock, 0);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	i_data = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (i_data[i]) {
+			retval = update_ind_extent_range(handle, inode,
+						le32_to_cpu(i_data[i]), lb);
+			if (retval)
+				break;
+		} else {
+			/* Only update the file block number */
+			lb->curr_block += max_entries;
+		}
+	}
+	put_bh(bh);
+	return retval;
+
+}
+
+static int update_tind_extent_range(handle_t *handle, struct inode *inode,
+				    ext4_fsblk_t pblock,
+				    struct migrate_struct *lb)
+{
+	struct buffer_head *bh;
+	__le32 *i_data;
+	int i, retval = 0;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = ext4_sb_bread(inode->i_sb, pblock, 0);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	i_data = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (i_data[i]) {
+			retval = update_dind_extent_range(handle, inode,
+						le32_to_cpu(i_data[i]), lb);
+			if (retval)
+				break;
+		} else {
+			/* Only update the file block number */
+			lb->curr_block += max_entries * max_entries;
+		}
+	}
+	put_bh(bh);
+	return retval;
+
+}
+
+static int free_dind_blocks(handle_t *handle,
+				struct inode *inode, __le32 i_data)
+{
+	int i;
+	__le32 *tmp_idata;
+	struct buffer_head *bh;
+	struct super_block *sb = inode->i_sb;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+	int err;
+
+	bh = ext4_sb_bread(sb, le32_to_cpu(i_data), 0);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	tmp_idata = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (tmp_idata[i]) {
+			err = ext4_journal_ensure_credits(handle,
+				EXT4_RESERVE_TRANS_BLOCKS,
+				ext4_free_metadata_revoke_credits(sb, 1));
+			if (err < 0) {
+				put_bh(bh);
+				return err;
+			}
+			ext4_free_blocks(handle, inode, NULL,
+					 le32_to_cpu(tmp_idata[i]), 1,
+					 EXT4_FREE_BLOCKS_METADATA |
+					 EXT4_FREE_BLOCKS_FORGET);
+		}
+	}
+	put_bh(bh);
+	err = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
+				ext4_free_metadata_revoke_credits(sb, 1));
+	if (err < 0)
+		return err;
+	ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
+			 EXT4_FREE_BLOCKS_METADATA |
+			 EXT4_FREE_BLOCKS_FORGET);
+	return 0;
+}
+
+static int free_tind_blocks(handle_t *handle,
+				struct inode *inode, __le32 i_data)
+{
+	int i, retval = 0;
+	__le32 *tmp_idata;
+	struct buffer_head *bh;
+	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+	bh = ext4_sb_bread(inode->i_sb, le32_to_cpu(i_data), 0);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	tmp_idata = (__le32 *)bh->b_data;
+	for (i = 0; i < max_entries; i++) {
+		if (tmp_idata[i]) {
+			retval = free_dind_blocks(handle,
+					inode, tmp_idata[i]);
+			if (retval) {
+				put_bh(bh);
+				return retval;
+			}
+		}
+	}
+	put_bh(bh);
+	retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
+			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
+	if (retval < 0)
+		return retval;
+	ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
+			 EXT4_FREE_BLOCKS_METADATA |
+			 EXT4_FREE_BLOCKS_FORGET);
+	return 0;
+}
+
+static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
+{
+	int retval;
+
+	/* ei->i_data[EXT4_IND_BLOCK] */
+	if (i_data[0]) {
+		retval = ext4_journal_ensure_credits(handle,
+			EXT4_RESERVE_TRANS_BLOCKS,
+			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
+		if (retval < 0)
+			return retval;
+		ext4_free_blocks(handle, inode, NULL,
+				le32_to_cpu(i_data[0]), 1,
+				 EXT4_FREE_BLOCKS_METADATA |
+				 EXT4_FREE_BLOCKS_FORGET);
+	}
+
+	/* ei->i_data[EXT4_DIND_BLOCK] */
+	if (i_data[1]) {
+		retval = free_dind_blocks(handle, inode, i_data[1]);
+		if (retval)
+			return retval;
+	}
+
+	/* ei->i_data[EXT4_TIND_BLOCK] */
+	if (i_data[2]) {
+		retval = free_tind_blocks(handle, inode, i_data[2]);
+		if (retval)
+			return retval;
+	}
+	return 0;
+}
+
+static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
+						struct inode *tmp_inode)
+{
+	int retval, retval2 = 0;
+	__le32	i_data[3];
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
+
+	/*
+	 * One credit accounted for writing the
+	 * i_data field of the original inode
+	 */
+	retval = ext4_journal_ensure_credits(handle, 1, 0);
+	if (retval < 0)
+		goto err_out;
+
+	i_data[0] = ei->i_data[EXT4_IND_BLOCK];
+	i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
+	i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	/*
+	 * if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
+	 * happened after we started the migrate. We need to
+	 * fail the migrate
+	 */
+	if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
+		retval = -EAGAIN;
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto err_out;
+	} else
+		ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
+	/*
+	 * We have the extent map build with the tmp inode.
+	 * Now copy the i_data across
+	 */
+	ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
+	memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
+
+	/*
+	 * Update i_blocks with the new blocks that got
+	 * allocated while adding extents for extent index
+	 * blocks.
+	 *
+	 * While converting to extents we need not
+	 * update the original inode i_blocks for extent blocks
+	 * via quota APIs. The quota update happened via tmp_inode already.
+	 */
+	spin_lock(&inode->i_lock);
+	inode->i_blocks += tmp_inode->i_blocks;
+	spin_unlock(&inode->i_lock);
+	up_write(&EXT4_I(inode)->i_data_sem);
+
+	/*
+	 * We mark the inode dirty after, because we decrement the
+	 * i_blocks when freeing the indirect meta-data blocks
+	 */
+	retval = free_ind_block(handle, inode, i_data);
+	retval2 = ext4_mark_inode_dirty(handle, inode);
+	if (unlikely(retval2 && !retval))
+		retval = retval2;
+
+err_out:
+	return retval;
+}
+
+static int free_ext_idx(handle_t *handle, struct inode *inode,
+					struct ext4_extent_idx *ix)
+{
+	int i, retval = 0;
+	ext4_fsblk_t block;
+	struct buffer_head *bh;
+	struct ext4_extent_header *eh;
+
+	block = ext4_idx_pblock(ix);
+	bh = ext4_sb_bread(inode->i_sb, block, 0);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	eh = (struct ext4_extent_header *)bh->b_data;
+	if (eh->eh_depth != 0) {
+		ix = EXT_FIRST_INDEX(eh);
+		for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
+			retval = free_ext_idx(handle, inode, ix);
+			if (retval) {
+				put_bh(bh);
+				return retval;
+			}
+		}
+	}
+	put_bh(bh);
+	retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
+			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
+	if (retval < 0)
+		return retval;
+	ext4_free_blocks(handle, inode, NULL, block, 1,
+			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
+	return 0;
+}
+
+/*
+ * Free the extent meta data blocks only
+ */
+static int free_ext_block(handle_t *handle, struct inode *inode)
+{
+	int i, retval = 0;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
+	struct ext4_extent_idx *ix;
+	if (eh->eh_depth == 0)
+		/*
+		 * No extra blocks allocated for extent meta data
+		 */
+		return 0;
+	ix = EXT_FIRST_INDEX(eh);
+	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
+		retval = free_ext_idx(handle, inode, ix);
+		if (retval)
+			return retval;
+	}
+	return retval;
+}
+
+int ext4_ext_migrate(struct inode *inode)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	handle_t *handle;
+	int retval = 0, i;
+	__le32 *i_data;
+	struct ext4_inode_info *ei;
+	struct inode *tmp_inode = NULL;
+	struct migrate_struct lb;
+	unsigned long max_entries;
+	__u32 goal, tmp_csum_seed;
+	uid_t owner[2];
+
+	/*
+	 * If the filesystem does not support extents, or the inode
+	 * already is extent-based, error out.
+	 */
+	if (!ext4_has_feature_extents(inode->i_sb) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) ||
+	    ext4_has_inline_data(inode))
+		return -EINVAL;
+
+	if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
+		/*
+		 * don't migrate fast symlink
+		 */
+		return retval;
+
+	percpu_down_write(&sbi->s_writepages_rwsem);
+
+	/*
+	 * Worst case we can touch the allocation bitmaps and a block
+	 * group descriptor block.  We do need need to worry about
+	 * credits for modifying the quota inode.
+	 */
+	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE,
+		3 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
+
+	if (IS_ERR(handle)) {
+		retval = PTR_ERR(handle);
+		goto out_unlock;
+	}
+	goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
+		EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
+	owner[0] = i_uid_read(inode);
+	owner[1] = i_gid_read(inode);
+	tmp_inode = ext4_new_inode(handle, d_inode(inode->i_sb->s_root),
+				   S_IFREG, NULL, goal, owner, 0);
+	if (IS_ERR(tmp_inode)) {
+		retval = PTR_ERR(tmp_inode);
+		ext4_journal_stop(handle);
+		goto out_unlock;
+	}
+	/*
+	 * Use the correct seed for checksum (i.e. the seed from 'inode').  This
+	 * is so that the metadata blocks will have the correct checksum after
+	 * the migration.
+	 */
+	ei = EXT4_I(inode);
+	tmp_csum_seed = EXT4_I(tmp_inode)->i_csum_seed;
+	EXT4_I(tmp_inode)->i_csum_seed = ei->i_csum_seed;
+	i_size_write(tmp_inode, i_size_read(inode));
+	/*
+	 * Set the i_nlink to zero so it will be deleted later
+	 * when we drop inode reference.
+	 */
+	clear_nlink(tmp_inode);
+
+	ext4_ext_tree_init(handle, tmp_inode);
+	ext4_journal_stop(handle);
+
+	/*
+	 * start with one credit accounted for
+	 * superblock modification.
+	 *
+	 * For the tmp_inode we already have committed the
+	 * transaction that created the inode. Later as and
+	 * when we add extents we extent the journal
+	 */
+	/*
+	 * Even though we take i_mutex we can still cause block
+	 * allocation via mmap write to holes. If we have allocated
+	 * new blocks we fail migrate.  New block allocation will
+	 * clear EXT4_STATE_EXT_MIGRATE flag.  The flag is updated
+	 * with i_data_sem held to prevent racing with block
+	 * allocation.
+	 */
+	down_read(&EXT4_I(inode)->i_data_sem);
+	ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
+	up_read((&EXT4_I(inode)->i_data_sem));
+
+	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
+	if (IS_ERR(handle)) {
+		retval = PTR_ERR(handle);
+		goto out_tmp_inode;
+	}
+
+	i_data = ei->i_data;
+	memset(&lb, 0, sizeof(lb));
+
+	/* 32 bit block address 4 bytes */
+	max_entries = inode->i_sb->s_blocksize >> 2;
+	for (i = 0; i < EXT4_NDIR_BLOCKS; i++) {
+		if (i_data[i]) {
+			retval = update_extent_range(handle, tmp_inode,
+						le32_to_cpu(i_data[i]), &lb);
+			if (retval)
+				goto err_out;
+		} else
+			lb.curr_block++;
+	}
+	if (i_data[EXT4_IND_BLOCK]) {
+		retval = update_ind_extent_range(handle, tmp_inode,
+				le32_to_cpu(i_data[EXT4_IND_BLOCK]), &lb);
+		if (retval)
+			goto err_out;
+	} else
+		lb.curr_block += max_entries;
+	if (i_data[EXT4_DIND_BLOCK]) {
+		retval = update_dind_extent_range(handle, tmp_inode,
+				le32_to_cpu(i_data[EXT4_DIND_BLOCK]), &lb);
+		if (retval)
+			goto err_out;
+	} else
+		lb.curr_block += max_entries * max_entries;
+	if (i_data[EXT4_TIND_BLOCK]) {
+		retval = update_tind_extent_range(handle, tmp_inode,
+				le32_to_cpu(i_data[EXT4_TIND_BLOCK]), &lb);
+		if (retval)
+			goto err_out;
+	}
+	/*
+	 * Build the last extent
+	 */
+	retval = finish_range(handle, tmp_inode, &lb);
+err_out:
+	if (retval)
+		/*
+		 * Failure case delete the extent information with the
+		 * tmp_inode
+		 */
+		free_ext_block(handle, tmp_inode);
+	else {
+		retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
+		if (retval)
+			/*
+			 * if we fail to swap inode data free the extent
+			 * details of the tmp inode
+			 */
+			free_ext_block(handle, tmp_inode);
+	}
+
+	/* We mark the tmp_inode dirty via ext4_ext_tree_init. */
+	retval = ext4_journal_ensure_credits(handle, 1, 0);
+	if (retval < 0)
+		goto out_stop;
+	/*
+	 * Mark the tmp_inode as of size zero
+	 */
+	i_size_write(tmp_inode, 0);
+
+	/*
+	 * set the  i_blocks count to zero
+	 * so that the ext4_evict_inode() does the
+	 * right job
+	 *
+	 * We don't need to take the i_lock because
+	 * the inode is not visible to user space.
+	 */
+	tmp_inode->i_blocks = 0;
+	EXT4_I(tmp_inode)->i_csum_seed = tmp_csum_seed;
+
+	/* Reset the extent details */
+	ext4_ext_tree_init(handle, tmp_inode);
+out_stop:
+	ext4_journal_stop(handle);
+out_tmp_inode:
+	unlock_new_inode(tmp_inode);
+	iput(tmp_inode);
+out_unlock:
+	percpu_up_write(&sbi->s_writepages_rwsem);
+	return retval;
+}
+
+/*
+ * Migrate a simple extent-based inode to use the i_blocks[] array
+ */
+int ext4_ind_migrate(struct inode *inode)
+{
+	struct ext4_extent_header	*eh;
+	struct ext4_sb_info		*sbi = EXT4_SB(inode->i_sb);
+	struct ext4_super_block		*es = sbi->s_es;
+	struct ext4_inode_info		*ei = EXT4_I(inode);
+	struct ext4_extent		*ex;
+	unsigned int			i, len;
+	ext4_lblk_t			start, end;
+	ext4_fsblk_t			blk;
+	handle_t			*handle;
+	int				ret, ret2 = 0;
+
+	if (!ext4_has_feature_extents(inode->i_sb) ||
+	    (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		return -EINVAL;
+
+	if (ext4_has_feature_bigalloc(inode->i_sb))
+		return -EOPNOTSUPP;
+
+	/*
+	 * In order to get correct extent info, force all delayed allocation
+	 * blocks to be allocated, otherwise delayed allocation blocks may not
+	 * be reflected and bypass the checks on extent header.
+	 */
+	if (test_opt(inode->i_sb, DELALLOC))
+		ext4_alloc_da_blocks(inode);
+
+	percpu_down_write(&sbi->s_writepages_rwsem);
+
+	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out_unlock;
+	}
+
+	down_write(&EXT4_I(inode)->i_data_sem);
+	ret = ext4_ext_check_inode(inode);
+	if (ret)
+		goto errout;
+
+	eh = ext_inode_hdr(inode);
+	ex  = EXT_FIRST_EXTENT(eh);
+	if (ext4_blocks_count(es) > EXT4_MAX_BLOCK_FILE_PHYS ||
+	    eh->eh_depth != 0 || le16_to_cpu(eh->eh_entries) > 1) {
+		ret = -EOPNOTSUPP;
+		goto errout;
+	}
+	if (eh->eh_entries == 0)
+		blk = len = start = end = 0;
+	else {
+		len = le16_to_cpu(ex->ee_len);
+		blk = ext4_ext_pblock(ex);
+		start = le32_to_cpu(ex->ee_block);
+		end = start + len - 1;
+		if (end >= EXT4_NDIR_BLOCKS) {
+			ret = -EOPNOTSUPP;
+			goto errout;
+		}
+	}
+
+	ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
+	memset(ei->i_data, 0, sizeof(ei->i_data));
+	for (i = start; i <= end; i++)
+		ei->i_data[i] = cpu_to_le32(blk++);
+	ret2 = ext4_mark_inode_dirty(handle, inode);
+	if (unlikely(ret2 && !ret))
+		ret = ret2;
+errout:
+	ext4_journal_stop(handle);
+	up_write(&EXT4_I(inode)->i_data_sem);
+out_unlock:
+	percpu_up_write(&sbi->s_writepages_rwsem);
+	return ret;
+}
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
new file mode 100644
index 000000000..7a9a8ed1d
--- /dev/null
+++ b/fs/ext4/mmp.c
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/random.h>
+#include <linux/buffer_head.h>
+#include <linux/utsname.h>
+#include <linux/kthread.h>
+
+#include "ext4.h"
+
+/* Checksumming functions */
+static __le32 ext4_mmp_csum(struct super_block *sb, struct mmp_struct *mmp)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int offset = offsetof(struct mmp_struct, mmp_checksum);
+	__u32 csum;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (char *)mmp, offset);
+
+	return cpu_to_le32(csum);
+}
+
+static int ext4_mmp_csum_verify(struct super_block *sb, struct mmp_struct *mmp)
+{
+	if (!ext4_has_metadata_csum(sb))
+		return 1;
+
+	return mmp->mmp_checksum == ext4_mmp_csum(sb, mmp);
+}
+
+static void ext4_mmp_csum_set(struct super_block *sb, struct mmp_struct *mmp)
+{
+	if (!ext4_has_metadata_csum(sb))
+		return;
+
+	mmp->mmp_checksum = ext4_mmp_csum(sb, mmp);
+}
+
+/*
+ * Write the MMP block using REQ_SYNC to try to get the block on-disk
+ * faster.
+ */
+static int write_mmp_block_thawed(struct super_block *sb,
+				  struct buffer_head *bh)
+{
+	struct mmp_struct *mmp = (struct mmp_struct *)(bh->b_data);
+
+	ext4_mmp_csum_set(sb, mmp);
+	lock_buffer(bh);
+	bh->b_end_io = end_buffer_write_sync;
+	get_bh(bh);
+	submit_bh(REQ_OP_WRITE, REQ_SYNC | REQ_META | REQ_PRIO, bh);
+	wait_on_buffer(bh);
+	if (unlikely(!buffer_uptodate(bh)))
+		return -EIO;
+	return 0;
+}
+
+static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
+{
+	int err;
+
+	/*
+	 * We protect against freezing so that we don't create dirty buffers
+	 * on frozen filesystem.
+	 */
+	sb_start_write(sb);
+	err = write_mmp_block_thawed(sb, bh);
+	sb_end_write(sb);
+	return err;
+}
+
+/*
+ * Read the MMP block. It _must_ be read from disk and hence we clear the
+ * uptodate flag on the buffer.
+ */
+static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
+			  ext4_fsblk_t mmp_block)
+{
+	struct mmp_struct *mmp;
+	int ret;
+
+	if (*bh)
+		clear_buffer_uptodate(*bh);
+
+	/* This would be sb_bread(sb, mmp_block), except we need to be sure
+	 * that the MD RAID device cache has been bypassed, and that the read
+	 * is not blocked in the elevator. */
+	if (!*bh) {
+		*bh = sb_getblk(sb, mmp_block);
+		if (!*bh) {
+			ret = -ENOMEM;
+			goto warn_exit;
+		}
+	}
+
+	lock_buffer(*bh);
+	ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL);
+	if (ret)
+		goto warn_exit;
+
+	mmp = (struct mmp_struct *)((*bh)->b_data);
+	if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC) {
+		ret = -EFSCORRUPTED;
+		goto warn_exit;
+	}
+	if (!ext4_mmp_csum_verify(sb, mmp)) {
+		ret = -EFSBADCRC;
+		goto warn_exit;
+	}
+	return 0;
+warn_exit:
+	brelse(*bh);
+	*bh = NULL;
+	ext4_warning(sb, "Error %d while reading MMP block %llu",
+		     ret, mmp_block);
+	return ret;
+}
+
+/*
+ * Dump as much information as possible to help the admin.
+ */
+void __dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
+		    const char *function, unsigned int line, const char *msg)
+{
+	__ext4_warning(sb, function, line, "%s", msg);
+	__ext4_warning(sb, function, line,
+		       "MMP failure info: last update time: %llu, last update node: %.*s, last update device: %.*s",
+		       (unsigned long long)le64_to_cpu(mmp->mmp_time),
+		       (int)sizeof(mmp->mmp_nodename), mmp->mmp_nodename,
+		       (int)sizeof(mmp->mmp_bdevname), mmp->mmp_bdevname);
+}
+
+/*
+ * kmmpd will update the MMP sequence every s_mmp_update_interval seconds
+ */
+static int kmmpd(void *data)
+{
+	struct super_block *sb = (struct super_block *) data;
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	struct buffer_head *bh = EXT4_SB(sb)->s_mmp_bh;
+	struct mmp_struct *mmp;
+	ext4_fsblk_t mmp_block;
+	u32 seq = 0;
+	unsigned long failed_writes = 0;
+	int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
+	unsigned mmp_check_interval;
+	unsigned long last_update_time;
+	unsigned long diff;
+	int retval;
+
+	mmp_block = le64_to_cpu(es->s_mmp_block);
+	mmp = (struct mmp_struct *)(bh->b_data);
+	mmp->mmp_time = cpu_to_le64(ktime_get_real_seconds());
+	/*
+	 * Start with the higher mmp_check_interval and reduce it if
+	 * the MMP block is being updated on time.
+	 */
+	mmp_check_interval = max(EXT4_MMP_CHECK_MULT * mmp_update_interval,
+				 EXT4_MMP_MIN_CHECK_INTERVAL);
+	mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
+	BUILD_BUG_ON(sizeof(mmp->mmp_bdevname) < BDEVNAME_SIZE);
+	bdevname(bh->b_bdev, mmp->mmp_bdevname);
+
+	memcpy(mmp->mmp_nodename, init_utsname()->nodename,
+	       sizeof(mmp->mmp_nodename));
+
+	while (!kthread_should_stop() && !sb_rdonly(sb)) {
+		if (!ext4_has_feature_mmp(sb)) {
+			ext4_warning(sb, "kmmpd being stopped since MMP feature"
+				     " has been disabled.");
+			goto wait_to_exit;
+		}
+		if (++seq > EXT4_MMP_SEQ_MAX)
+			seq = 1;
+
+		mmp->mmp_seq = cpu_to_le32(seq);
+		mmp->mmp_time = cpu_to_le64(ktime_get_real_seconds());
+		last_update_time = jiffies;
+
+		retval = write_mmp_block(sb, bh);
+		/*
+		 * Don't spew too many error messages. Print one every
+		 * (s_mmp_update_interval * 60) seconds.
+		 */
+		if (retval) {
+			if ((failed_writes % 60) == 0) {
+				ext4_error_err(sb, -retval,
+					       "Error writing to MMP block");
+			}
+			failed_writes++;
+		}
+
+		diff = jiffies - last_update_time;
+		if (diff < mmp_update_interval * HZ)
+			schedule_timeout_interruptible(mmp_update_interval *
+						       HZ - diff);
+
+		/*
+		 * We need to make sure that more than mmp_check_interval
+		 * seconds have not passed since writing. If that has happened
+		 * we need to check if the MMP block is as we left it.
+		 */
+		diff = jiffies - last_update_time;
+		if (diff > mmp_check_interval * HZ) {
+			struct buffer_head *bh_check = NULL;
+			struct mmp_struct *mmp_check;
+
+			retval = read_mmp_block(sb, &bh_check, mmp_block);
+			if (retval) {
+				ext4_error_err(sb, -retval,
+					       "error reading MMP data: %d",
+					       retval);
+				goto wait_to_exit;
+			}
+
+			mmp_check = (struct mmp_struct *)(bh_check->b_data);
+			if (mmp->mmp_seq != mmp_check->mmp_seq ||
+			    memcmp(mmp->mmp_nodename, mmp_check->mmp_nodename,
+				   sizeof(mmp->mmp_nodename))) {
+				dump_mmp_msg(sb, mmp_check,
+					     "Error while updating MMP info. "
+					     "The filesystem seems to have been"
+					     " multiply mounted.");
+				ext4_error_err(sb, EBUSY, "abort");
+				put_bh(bh_check);
+				retval = -EBUSY;
+				goto wait_to_exit;
+			}
+			put_bh(bh_check);
+		}
+
+		 /*
+		 * Adjust the mmp_check_interval depending on how much time
+		 * it took for the MMP block to be written.
+		 */
+		mmp_check_interval = max(min(EXT4_MMP_CHECK_MULT * diff / HZ,
+					     EXT4_MMP_MAX_CHECK_INTERVAL),
+					 EXT4_MMP_MIN_CHECK_INTERVAL);
+		mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
+	}
+
+	/*
+	 * Unmount seems to be clean.
+	 */
+	mmp->mmp_seq = cpu_to_le32(EXT4_MMP_SEQ_CLEAN);
+	mmp->mmp_time = cpu_to_le64(ktime_get_real_seconds());
+
+	retval = write_mmp_block(sb, bh);
+
+wait_to_exit:
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (!kthread_should_stop())
+			schedule();
+	}
+	set_current_state(TASK_RUNNING);
+	return retval;
+}
+
+void ext4_stop_mmpd(struct ext4_sb_info *sbi)
+{
+	if (sbi->s_mmp_tsk) {
+		kthread_stop(sbi->s_mmp_tsk);
+		brelse(sbi->s_mmp_bh);
+		sbi->s_mmp_tsk = NULL;
+	}
+}
+
+/*
+ * Get a random new sequence number but make sure it is not greater than
+ * EXT4_MMP_SEQ_MAX.
+ */
+static unsigned int mmp_new_seq(void)
+{
+	u32 new_seq;
+
+	do {
+		new_seq = prandom_u32();
+	} while (new_seq > EXT4_MMP_SEQ_MAX);
+
+	return new_seq;
+}
+
+/*
+ * Protect the filesystem from being mounted more than once.
+ */
+int ext4_multi_mount_protect(struct super_block *sb,
+				    ext4_fsblk_t mmp_block)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	struct buffer_head *bh = NULL;
+	struct mmp_struct *mmp = NULL;
+	u32 seq;
+	unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
+	unsigned int wait_time = 0;
+	int retval;
+
+	if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
+	    mmp_block >= ext4_blocks_count(es)) {
+		ext4_warning(sb, "Invalid MMP block in superblock");
+		retval = -EINVAL;
+		goto failed;
+	}
+
+	retval = read_mmp_block(sb, &bh, mmp_block);
+	if (retval)
+		goto failed;
+
+	mmp = (struct mmp_struct *)(bh->b_data);
+
+	if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL)
+		mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL;
+
+	/*
+	 * If check_interval in MMP block is larger, use that instead of
+	 * update_interval from the superblock.
+	 */
+	if (le16_to_cpu(mmp->mmp_check_interval) > mmp_check_interval)
+		mmp_check_interval = le16_to_cpu(mmp->mmp_check_interval);
+
+	seq = le32_to_cpu(mmp->mmp_seq);
+	if (seq == EXT4_MMP_SEQ_CLEAN)
+		goto skip;
+
+	if (seq == EXT4_MMP_SEQ_FSCK) {
+		dump_mmp_msg(sb, mmp, "fsck is running on the filesystem");
+		retval = -EBUSY;
+		goto failed;
+	}
+
+	wait_time = min(mmp_check_interval * 2 + 1,
+			mmp_check_interval + 60);
+
+	/* Print MMP interval if more than 20 secs. */
+	if (wait_time > EXT4_MMP_MIN_CHECK_INTERVAL * 4)
+		ext4_warning(sb, "MMP interval %u higher than expected, please"
+			     " wait.\n", wait_time * 2);
+
+	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
+		ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+		retval = -ETIMEDOUT;
+		goto failed;
+	}
+
+	retval = read_mmp_block(sb, &bh, mmp_block);
+	if (retval)
+		goto failed;
+	mmp = (struct mmp_struct *)(bh->b_data);
+	if (seq != le32_to_cpu(mmp->mmp_seq)) {
+		dump_mmp_msg(sb, mmp,
+			     "Device is already active on another node.");
+		retval = -EBUSY;
+		goto failed;
+	}
+
+skip:
+	/*
+	 * write a new random sequence number.
+	 */
+	seq = mmp_new_seq();
+	mmp->mmp_seq = cpu_to_le32(seq);
+
+	/*
+	 * On mount / remount we are protected against fs freezing (by s_umount
+	 * semaphore) and grabbing freeze protection upsets lockdep
+	 */
+	retval = write_mmp_block_thawed(sb, bh);
+	if (retval)
+		goto failed;
+
+	/*
+	 * wait for MMP interval and check mmp_seq.
+	 */
+	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
+		ext4_warning(sb, "MMP startup interrupted, failing mount");
+		retval = -ETIMEDOUT;
+		goto failed;
+	}
+
+	retval = read_mmp_block(sb, &bh, mmp_block);
+	if (retval)
+		goto failed;
+	mmp = (struct mmp_struct *)(bh->b_data);
+	if (seq != le32_to_cpu(mmp->mmp_seq)) {
+		dump_mmp_msg(sb, mmp,
+			     "Device is already active on another node.");
+		retval = -EBUSY;
+		goto failed;
+	}
+
+	EXT4_SB(sb)->s_mmp_bh = bh;
+
+	/*
+	 * Start a kernel thread to update the MMP block periodically.
+	 */
+	EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, sb, "kmmpd-%.*s",
+					     (int)sizeof(mmp->mmp_bdevname),
+					     bdevname(bh->b_bdev,
+						      mmp->mmp_bdevname));
+	if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
+		EXT4_SB(sb)->s_mmp_tsk = NULL;
+		ext4_warning(sb, "Unable to create kmmpd thread for %s.",
+			     sb->s_id);
+		retval = -ENOMEM;
+		goto failed;
+	}
+
+	return 0;
+
+failed:
+	brelse(bh);
+	return retval;
+}
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
new file mode 100644
index 000000000..64a579734
--- /dev/null
+++ b/fs/ext4/move_extent.c
@@ -0,0 +1,699 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
+ * Written by Takashi Sato <t-sato@yk.jp.nec.com>
+ *            Akira Fujita <a-fujita@rs.jp.nec.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include <linux/slab.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "ext4_extents.h"
+
+/**
+ * get_ext_path() - Find an extent path for designated logical block number.
+ * @inode:	inode to be searched
+ * @lblock:	logical block number to find an extent path
+ * @ppath:	pointer to an extent path pointer (for output)
+ *
+ * ext4_find_extent wrapper. Return 0 on success, or a negative error value
+ * on failure.
+ */
+static inline int
+get_ext_path(struct inode *inode, ext4_lblk_t lblock,
+		struct ext4_ext_path **ppath)
+{
+	struct ext4_ext_path *path;
+
+	path = ext4_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	if (path[ext_depth(inode)].p_ext == NULL) {
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		*ppath = NULL;
+		return -ENODATA;
+	}
+	*ppath = path;
+	return 0;
+}
+
+/**
+ * ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem
+ * @first: inode to be locked
+ * @second: inode to be locked
+ *
+ * Acquire write lock of i_data_sem of the two inodes
+ */
+void
+ext4_double_down_write_data_sem(struct inode *first, struct inode *second)
+{
+	if (first < second) {
+		down_write(&EXT4_I(first)->i_data_sem);
+		down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER);
+	} else {
+		down_write(&EXT4_I(second)->i_data_sem);
+		down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER);
+
+	}
+}
+
+/**
+ * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem
+ *
+ * @orig_inode:		original inode structure to be released its lock first
+ * @donor_inode:	donor inode structure to be released its lock second
+ * Release write lock of i_data_sem of two inodes (orig and donor).
+ */
+void
+ext4_double_up_write_data_sem(struct inode *orig_inode,
+			      struct inode *donor_inode)
+{
+	up_write(&EXT4_I(orig_inode)->i_data_sem);
+	up_write(&EXT4_I(donor_inode)->i_data_sem);
+}
+
+/**
+ * mext_check_coverage - Check that all extents in range has the same type
+ *
+ * @inode:		inode in question
+ * @from:		block offset of inode
+ * @count:		block count to be checked
+ * @unwritten:		extents expected to be unwritten
+ * @err:		pointer to save error value
+ *
+ * Return 1 if all extents in range has expected type, and zero otherwise.
+ */
+static int
+mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
+		    int unwritten, int *err)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent *ext;
+	int ret = 0;
+	ext4_lblk_t last = from + count;
+	while (from < last) {
+		*err = get_ext_path(inode, from, &path);
+		if (*err)
+			goto out;
+		ext = path[ext_depth(inode)].p_ext;
+		if (unwritten != ext4_ext_is_unwritten(ext))
+			goto out;
+		from += ext4_ext_get_actual_len(ext);
+		ext4_ext_drop_refs(path);
+	}
+	ret = 1;
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	return ret;
+}
+
+/**
+ * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2
+ *
+ * @inode1:	the inode structure
+ * @inode2:	the inode structure
+ * @index1:	page index
+ * @index2:	page index
+ * @page:	result page vector
+ *
+ * Grab two locked pages for inode's by inode order
+ */
+static int
+mext_page_double_lock(struct inode *inode1, struct inode *inode2,
+		      pgoff_t index1, pgoff_t index2, struct page *page[2])
+{
+	struct address_space *mapping[2];
+	unsigned fl = AOP_FLAG_NOFS;
+
+	BUG_ON(!inode1 || !inode2);
+	if (inode1 < inode2) {
+		mapping[0] = inode1->i_mapping;
+		mapping[1] = inode2->i_mapping;
+	} else {
+		swap(index1, index2);
+		mapping[0] = inode2->i_mapping;
+		mapping[1] = inode1->i_mapping;
+	}
+
+	page[0] = grab_cache_page_write_begin(mapping[0], index1, fl);
+	if (!page[0])
+		return -ENOMEM;
+
+	page[1] = grab_cache_page_write_begin(mapping[1], index2, fl);
+	if (!page[1]) {
+		unlock_page(page[0]);
+		put_page(page[0]);
+		return -ENOMEM;
+	}
+	/*
+	 * grab_cache_page_write_begin() may not wait on page's writeback if
+	 * BDI not demand that. But it is reasonable to be very conservative
+	 * here and explicitly wait on page's writeback
+	 */
+	wait_on_page_writeback(page[0]);
+	wait_on_page_writeback(page[1]);
+	if (inode1 > inode2)
+		swap(page[0], page[1]);
+
+	return 0;
+}
+
+/* Force page buffers uptodate w/o dropping page's lock */
+static int
+mext_page_mkuptodate(struct page *page, unsigned from, unsigned to)
+{
+	struct inode *inode = page->mapping->host;
+	sector_t block;
+	struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
+	unsigned int blocksize, block_start, block_end;
+	int i, err,  nr = 0, partial = 0;
+	BUG_ON(!PageLocked(page));
+	BUG_ON(PageWriteback(page));
+
+	if (PageUptodate(page))
+		return 0;
+
+	blocksize = i_blocksize(inode);
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, blocksize, 0);
+
+	head = page_buffers(page);
+	block = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits);
+	for (bh = head, block_start = 0; bh != head || !block_start;
+	     block++, block_start = block_end, bh = bh->b_this_page) {
+		block_end = block_start + blocksize;
+		if (block_end <= from || block_start >= to) {
+			if (!buffer_uptodate(bh))
+				partial = 1;
+			continue;
+		}
+		if (buffer_uptodate(bh))
+			continue;
+		if (!buffer_mapped(bh)) {
+			err = ext4_get_block(inode, block, bh, 0);
+			if (err) {
+				SetPageError(page);
+				return err;
+			}
+			if (!buffer_mapped(bh)) {
+				zero_user(page, block_start, blocksize);
+				set_buffer_uptodate(bh);
+				continue;
+			}
+		}
+		BUG_ON(nr >= MAX_BUF_PER_PAGE);
+		arr[nr++] = bh;
+	}
+	/* No io required */
+	if (!nr)
+		goto out;
+
+	for (i = 0; i < nr; i++) {
+		bh = arr[i];
+		if (!bh_uptodate_or_lock(bh)) {
+			err = ext4_read_bh(bh, 0, NULL);
+			if (err)
+				return err;
+		}
+	}
+out:
+	if (!partial)
+		SetPageUptodate(page);
+	return 0;
+}
+
+/**
+ * move_extent_per_page - Move extent data per page
+ *
+ * @o_filp:			file structure of original file
+ * @donor_inode:		donor inode
+ * @orig_page_offset:		page index on original file
+ * @donor_page_offset:		page index on donor file
+ * @data_offset_in_page:	block index where data swapping starts
+ * @block_len_in_page:		the number of blocks to be swapped
+ * @unwritten:			orig extent is unwritten or not
+ * @err:			pointer to save return value
+ *
+ * Save the data in original inode blocks and replace original inode extents
+ * with donor inode extents by calling ext4_swap_extents().
+ * Finally, write out the saved data in new original inode blocks. Return
+ * replaced block count.
+ */
+static int
+move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
+		     pgoff_t orig_page_offset, pgoff_t donor_page_offset,
+		     int data_offset_in_page,
+		     int block_len_in_page, int unwritten, int *err)
+{
+	struct inode *orig_inode = file_inode(o_filp);
+	struct page *pagep[2] = {NULL, NULL};
+	handle_t *handle;
+	ext4_lblk_t orig_blk_offset, donor_blk_offset;
+	unsigned long blocksize = orig_inode->i_sb->s_blocksize;
+	unsigned int tmp_data_size, data_size, replaced_size;
+	int i, err2, jblocks, retries = 0;
+	int replaced_count = 0;
+	int from = data_offset_in_page << orig_inode->i_blkbits;
+	int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
+	struct super_block *sb = orig_inode->i_sb;
+	struct buffer_head *bh = NULL;
+
+	/*
+	 * It needs twice the amount of ordinary journal buffers because
+	 * inode and donor_inode may change each different metadata blocks.
+	 */
+again:
+	*err = 0;
+	jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
+	handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks);
+	if (IS_ERR(handle)) {
+		*err = PTR_ERR(handle);
+		return 0;
+	}
+
+	orig_blk_offset = orig_page_offset * blocks_per_page +
+		data_offset_in_page;
+
+	donor_blk_offset = donor_page_offset * blocks_per_page +
+		data_offset_in_page;
+
+	/* Calculate data_size */
+	if ((orig_blk_offset + block_len_in_page - 1) ==
+	    ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
+		/* Replace the last block */
+		tmp_data_size = orig_inode->i_size & (blocksize - 1);
+		/*
+		 * If data_size equal zero, it shows data_size is multiples of
+		 * blocksize. So we set appropriate value.
+		 */
+		if (tmp_data_size == 0)
+			tmp_data_size = blocksize;
+
+		data_size = tmp_data_size +
+			((block_len_in_page - 1) << orig_inode->i_blkbits);
+	} else
+		data_size = block_len_in_page << orig_inode->i_blkbits;
+
+	replaced_size = data_size;
+
+	*err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset,
+				     donor_page_offset, pagep);
+	if (unlikely(*err < 0))
+		goto stop_journal;
+	/*
+	 * If orig extent was unwritten it can become initialized
+	 * at any time after i_data_sem was dropped, in order to
+	 * serialize with delalloc we have recheck extent while we
+	 * hold page's lock, if it is still the case data copy is not
+	 * necessary, just swap data blocks between orig and donor.
+	 */
+	if (unwritten) {
+		ext4_double_down_write_data_sem(orig_inode, donor_inode);
+		/* If any of extents in range became initialized we have to
+		 * fallback to data copying */
+		unwritten = mext_check_coverage(orig_inode, orig_blk_offset,
+						block_len_in_page, 1, err);
+		if (*err)
+			goto drop_data_sem;
+
+		unwritten &= mext_check_coverage(donor_inode, donor_blk_offset,
+						 block_len_in_page, 1, err);
+		if (*err)
+			goto drop_data_sem;
+
+		if (!unwritten) {
+			ext4_double_up_write_data_sem(orig_inode, donor_inode);
+			goto data_copy;
+		}
+		if ((page_has_private(pagep[0]) &&
+		     !try_to_release_page(pagep[0], 0)) ||
+		    (page_has_private(pagep[1]) &&
+		     !try_to_release_page(pagep[1], 0))) {
+			*err = -EBUSY;
+			goto drop_data_sem;
+		}
+		replaced_count = ext4_swap_extents(handle, orig_inode,
+						   donor_inode, orig_blk_offset,
+						   donor_blk_offset,
+						   block_len_in_page, 1, err);
+	drop_data_sem:
+		ext4_double_up_write_data_sem(orig_inode, donor_inode);
+		goto unlock_pages;
+	}
+data_copy:
+	*err = mext_page_mkuptodate(pagep[0], from, from + replaced_size);
+	if (*err)
+		goto unlock_pages;
+
+	/* At this point all buffers in range are uptodate, old mapping layout
+	 * is no longer required, try to drop it now. */
+	if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) ||
+	    (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) {
+		*err = -EBUSY;
+		goto unlock_pages;
+	}
+	ext4_double_down_write_data_sem(orig_inode, donor_inode);
+	replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode,
+					       orig_blk_offset, donor_blk_offset,
+					   block_len_in_page, 1, err);
+	ext4_double_up_write_data_sem(orig_inode, donor_inode);
+	if (*err) {
+		if (replaced_count) {
+			block_len_in_page = replaced_count;
+			replaced_size =
+				block_len_in_page << orig_inode->i_blkbits;
+		} else
+			goto unlock_pages;
+	}
+	/* Perform all necessary steps similar write_begin()/write_end()
+	 * but keeping in mind that i_size will not change */
+	if (!page_has_buffers(pagep[0]))
+		create_empty_buffers(pagep[0], 1 << orig_inode->i_blkbits, 0);
+	bh = page_buffers(pagep[0]);
+	for (i = 0; i < data_offset_in_page; i++)
+		bh = bh->b_this_page;
+	for (i = 0; i < block_len_in_page; i++) {
+		*err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0);
+		if (*err < 0)
+			break;
+		bh = bh->b_this_page;
+	}
+	if (!*err)
+		*err = block_commit_write(pagep[0], from, from + replaced_size);
+
+	if (unlikely(*err < 0))
+		goto repair_branches;
+
+	/* Even in case of data=writeback it is reasonable to pin
+	 * inode to transaction, to prevent unexpected data loss */
+	*err = ext4_jbd2_inode_add_write(handle, orig_inode,
+			(loff_t)orig_page_offset << PAGE_SHIFT, replaced_size);
+
+unlock_pages:
+	unlock_page(pagep[0]);
+	put_page(pagep[0]);
+	unlock_page(pagep[1]);
+	put_page(pagep[1]);
+stop_journal:
+	ext4_journal_stop(handle);
+	if (*err == -ENOSPC &&
+	    ext4_should_retry_alloc(sb, &retries))
+		goto again;
+	/* Buffer was busy because probably is pinned to journal transaction,
+	 * force transaction commit may help to free it. */
+	if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal &&
+	    jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal))
+		goto again;
+	return replaced_count;
+
+repair_branches:
+	/*
+	 * This should never ever happen!
+	 * Extents are swapped already, but we are not able to copy data.
+	 * Try to swap extents to it's original places
+	 */
+	ext4_double_down_write_data_sem(orig_inode, donor_inode);
+	replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode,
+					       orig_blk_offset, donor_blk_offset,
+					   block_len_in_page, 0, &err2);
+	ext4_double_up_write_data_sem(orig_inode, donor_inode);
+	if (replaced_count != block_len_in_page) {
+		ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset),
+				       EIO, "Unable to copy data block,"
+				       " data will be lost.");
+		*err = -EIO;
+	}
+	replaced_count = 0;
+	goto unlock_pages;
+}
+
+/**
+ * mext_check_arguments - Check whether move extent can be done
+ *
+ * @orig_inode:		original inode
+ * @donor_inode:	donor inode
+ * @orig_start:		logical start offset in block for orig
+ * @donor_start:	logical start offset in block for donor
+ * @len:		the number of blocks to be moved
+ *
+ * Check the arguments of ext4_move_extents() whether the files can be
+ * exchanged with each other.
+ * Return 0 on success, or a negative error value on failure.
+ */
+static int
+mext_check_arguments(struct inode *orig_inode,
+		     struct inode *donor_inode, __u64 orig_start,
+		     __u64 donor_start, __u64 *len)
+{
+	__u64 orig_eof, donor_eof;
+	unsigned int blkbits = orig_inode->i_blkbits;
+	unsigned int blocksize = 1 << blkbits;
+
+	orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits;
+	donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits;
+
+
+	if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
+		ext4_debug("ext4 move extent: suid or sgid is set"
+			   " to donor file [ino:orig %lu, donor %lu]\n",
+			   orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
+		return -EPERM;
+
+	/* Ext4 move extent does not support swapfile */
+	if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
+		ext4_debug("ext4 move extent: The argument files should "
+			"not be swapfile [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EBUSY;
+	}
+
+	if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) {
+		ext4_debug("ext4 move extent: The argument files should "
+			"not be quota files [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EBUSY;
+	}
+
+	/* Ext4 move extent supports only extent based file */
+	if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
+		ext4_debug("ext4 move extent: orig file is not extents "
+			"based file [ino:orig %lu]\n", orig_inode->i_ino);
+		return -EOPNOTSUPP;
+	} else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
+		ext4_debug("ext4 move extent: donor file is not extents "
+			"based file [ino:donor %lu]\n", donor_inode->i_ino);
+		return -EOPNOTSUPP;
+	}
+
+	if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
+		ext4_debug("ext4 move extent: File size is 0 byte\n");
+		return -EINVAL;
+	}
+
+	/* Start offset should be same */
+	if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) !=
+	    (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) {
+		ext4_debug("ext4 move extent: orig and donor's start "
+			"offsets are not aligned [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	if ((orig_start >= EXT_MAX_BLOCKS) ||
+	    (donor_start >= EXT_MAX_BLOCKS) ||
+	    (*len > EXT_MAX_BLOCKS) ||
+	    (donor_start + *len >= EXT_MAX_BLOCKS) ||
+	    (orig_start + *len >= EXT_MAX_BLOCKS))  {
+		ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
+			"[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+	if (orig_eof <= orig_start)
+		*len = 0;
+	else if (orig_eof < orig_start + *len - 1)
+		*len = orig_eof - orig_start;
+	if (donor_eof <= donor_start)
+		*len = 0;
+	else if (donor_eof < donor_start + *len - 1)
+		*len = donor_eof - donor_start;
+	if (!*len) {
+		ext4_debug("ext4 move extent: len should not be 0 "
+			"[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
+			donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * ext4_move_extents - Exchange the specified range of a file
+ *
+ * @o_filp:		file structure of the original file
+ * @d_filp:		file structure of the donor file
+ * @orig_blk:		start offset in block for orig
+ * @donor_blk:		start offset in block for donor
+ * @len:		the number of blocks to be moved
+ * @moved_len:		moved block length
+ *
+ * This function returns 0 and moved block length is set in moved_len
+ * if succeed, otherwise returns error value.
+ *
+ */
+int
+ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
+		  __u64 donor_blk, __u64 len, __u64 *moved_len)
+{
+	struct inode *orig_inode = file_inode(o_filp);
+	struct inode *donor_inode = file_inode(d_filp);
+	struct ext4_ext_path *path = NULL;
+	int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
+	ext4_lblk_t o_end, o_start = orig_blk;
+	ext4_lblk_t d_start = donor_blk;
+	int ret;
+
+	if (orig_inode->i_sb != donor_inode->i_sb) {
+		ext4_debug("ext4 move extent: The argument files "
+			"should be in same FS [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	/* orig and donor should be different inodes */
+	if (orig_inode == donor_inode) {
+		ext4_debug("ext4 move extent: The argument files should not "
+			"be same inode [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	/* Regular file check */
+	if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
+		ext4_debug("ext4 move extent: The argument files should be "
+			"regular file [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
+	/* TODO: it's not obvious how to swap blocks for inodes with full
+	   journaling enabled */
+	if (ext4_should_journal_data(orig_inode) ||
+	    ext4_should_journal_data(donor_inode)) {
+		ext4_msg(orig_inode->i_sb, KERN_ERR,
+			 "Online defrag not supported with data journaling");
+		return -EOPNOTSUPP;
+	}
+
+	if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) {
+		ext4_msg(orig_inode->i_sb, KERN_ERR,
+			 "Online defrag not supported for encrypted files");
+		return -EOPNOTSUPP;
+	}
+
+	/* Protect orig and donor inodes against a truncate */
+	lock_two_nondirectories(orig_inode, donor_inode);
+
+	/* Wait for all existing dio workers */
+	inode_dio_wait(orig_inode);
+	inode_dio_wait(donor_inode);
+
+	/* Protect extent tree against block allocations via delalloc */
+	ext4_double_down_write_data_sem(orig_inode, donor_inode);
+	/* Check the filesystem environment whether move_extent can be done */
+	ret = mext_check_arguments(orig_inode, donor_inode, orig_blk,
+				    donor_blk, &len);
+	if (ret)
+		goto out;
+	o_end = o_start + len;
+
+	while (o_start < o_end) {
+		struct ext4_extent *ex;
+		ext4_lblk_t cur_blk, next_blk;
+		pgoff_t orig_page_index, donor_page_index;
+		int offset_in_page;
+		int unwritten, cur_len;
+
+		ret = get_ext_path(orig_inode, o_start, &path);
+		if (ret)
+			goto out;
+		ex = path[path->p_depth].p_ext;
+		next_blk = ext4_ext_next_allocated_block(path);
+		cur_blk = le32_to_cpu(ex->ee_block);
+		cur_len = ext4_ext_get_actual_len(ex);
+		/* Check hole before the start pos */
+		if (cur_blk + cur_len - 1 < o_start) {
+			if (next_blk == EXT_MAX_BLOCKS) {
+				o_start = o_end;
+				ret = -ENODATA;
+				goto out;
+			}
+			d_start += next_blk - o_start;
+			o_start = next_blk;
+			continue;
+		/* Check hole after the start pos */
+		} else if (cur_blk > o_start) {
+			/* Skip hole */
+			d_start += cur_blk - o_start;
+			o_start = cur_blk;
+			/* Extent inside requested range ?*/
+			if (cur_blk >= o_end)
+				goto out;
+		} else { /* in_range(o_start, o_blk, o_len) */
+			cur_len += cur_blk - o_start;
+		}
+		unwritten = ext4_ext_is_unwritten(ex);
+		if (o_end - o_start < cur_len)
+			cur_len = o_end - o_start;
+
+		orig_page_index = o_start >> (PAGE_SHIFT -
+					       orig_inode->i_blkbits);
+		donor_page_index = d_start >> (PAGE_SHIFT -
+					       donor_inode->i_blkbits);
+		offset_in_page = o_start % blocks_per_page;
+		if (cur_len > blocks_per_page- offset_in_page)
+			cur_len = blocks_per_page - offset_in_page;
+		/*
+		 * Up semaphore to avoid following problems:
+		 * a. transaction deadlock among ext4_journal_start,
+		 *    ->write_begin via pagefault, and jbd2_journal_commit
+		 * b. racing with ->readpage, ->write_begin, and ext4_get_block
+		 *    in move_extent_per_page
+		 */
+		ext4_double_up_write_data_sem(orig_inode, donor_inode);
+		/* Swap original branches with new branches */
+		move_extent_per_page(o_filp, donor_inode,
+				     orig_page_index, donor_page_index,
+				     offset_in_page, cur_len,
+				     unwritten, &ret);
+		ext4_double_down_write_data_sem(orig_inode, donor_inode);
+		if (ret < 0)
+			break;
+		o_start += cur_len;
+		d_start += cur_len;
+	}
+	*moved_len = o_start - orig_blk;
+	if (*moved_len > len)
+		*moved_len = len;
+
+out:
+	if (*moved_len) {
+		ext4_discard_preallocations(orig_inode, 0);
+		ext4_discard_preallocations(donor_inode, 0);
+	}
+
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	ext4_double_up_write_data_sem(orig_inode, donor_inode);
+	unlock_two_nondirectories(orig_inode, donor_inode);
+
+	return ret;
+}
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
new file mode 100644
index 000000000..a50eb4c61
--- /dev/null
+++ b/fs/ext4/namei.c
@@ -0,0 +1,4264 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/namei.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/namei.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *  Directory entry file type support and forward compatibility hooks
+ *	for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
+ *  Hash Tree Directory indexing (c)
+ *	Daniel Phillips, 2001
+ *  Hash Tree Directory indexing porting
+ *	Christopher Li, 2002
+ *  Hash Tree Directory indexing cleanup
+ *	Theodore Ts'o, 2002
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/time.h>
+#include <linux/fcntl.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/bio.h>
+#include <linux/iversion.h>
+#include <linux/unicode.h>
+#include "ext4.h"
+#include "ext4_jbd2.h"
+
+#include "xattr.h"
+#include "acl.h"
+
+#include <trace/events/ext4.h>
+/*
+ * define how far ahead to read directories while searching them.
+ */
+#define NAMEI_RA_CHUNKS  2
+#define NAMEI_RA_BLOCKS  4
+#define NAMEI_RA_SIZE	     (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
+
+static struct buffer_head *ext4_append(handle_t *handle,
+					struct inode *inode,
+					ext4_lblk_t *block)
+{
+	struct ext4_map_blocks map;
+	struct buffer_head *bh;
+	int err;
+
+	if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
+		     ((inode->i_size >> 10) >=
+		      EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
+		return ERR_PTR(-ENOSPC);
+
+	*block = inode->i_size >> inode->i_sb->s_blocksize_bits;
+	map.m_lblk = *block;
+	map.m_len = 1;
+
+	/*
+	 * We're appending new directory block. Make sure the block is not
+	 * allocated yet, otherwise we will end up corrupting the
+	 * directory.
+	 */
+	err = ext4_map_blocks(NULL, inode, &map, 0);
+	if (err < 0)
+		return ERR_PTR(err);
+	if (err) {
+		EXT4_ERROR_INODE(inode, "Logical block already allocated");
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+
+	bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
+	if (IS_ERR(bh))
+		return bh;
+	inode->i_size += inode->i_sb->s_blocksize;
+	EXT4_I(inode)->i_disksize = inode->i_size;
+	BUFFER_TRACE(bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, bh);
+	if (err) {
+		brelse(bh);
+		ext4_std_error(inode->i_sb, err);
+		return ERR_PTR(err);
+	}
+	return bh;
+}
+
+static int ext4_dx_csum_verify(struct inode *inode,
+			       struct ext4_dir_entry *dirent);
+
+/*
+ * Hints to ext4_read_dirblock regarding whether we expect a directory
+ * block being read to be an index block, or a block containing
+ * directory entries (and if the latter, whether it was found via a
+ * logical block in an htree index block).  This is used to control
+ * what sort of sanity checkinig ext4_read_dirblock() will do on the
+ * directory block read from the storage device.  EITHER will means
+ * the caller doesn't know what kind of directory block will be read,
+ * so no specific verification will be done.
+ */
+typedef enum {
+	EITHER, INDEX, DIRENT, DIRENT_HTREE
+} dirblock_type_t;
+
+#define ext4_read_dirblock(inode, block, type) \
+	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
+
+static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
+						ext4_lblk_t block,
+						dirblock_type_t type,
+						const char *func,
+						unsigned int line)
+{
+	struct buffer_head *bh;
+	struct ext4_dir_entry *dirent;
+	int is_dx_block = 0;
+
+	if (block >= inode->i_size >> inode->i_blkbits) {
+		ext4_error_inode(inode, func, line, block,
+		       "Attempting to read directory block (%u) that is past i_size (%llu)",
+		       block, inode->i_size);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+
+	if (ext4_simulate_fail(inode->i_sb, EXT4_SIM_DIRBLOCK_EIO))
+		bh = ERR_PTR(-EIO);
+	else
+		bh = ext4_bread(NULL, inode, block, 0);
+	if (IS_ERR(bh)) {
+		__ext4_warning(inode->i_sb, func, line,
+			       "inode #%lu: lblock %lu: comm %s: "
+			       "error %ld reading directory block",
+			       inode->i_ino, (unsigned long)block,
+			       current->comm, PTR_ERR(bh));
+
+		return bh;
+	}
+	if (!bh && (type == INDEX || type == DIRENT_HTREE)) {
+		ext4_error_inode(inode, func, line, block,
+				 "Directory hole found for htree %s block",
+				 (type == INDEX) ? "index" : "leaf");
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+	if (!bh)
+		return NULL;
+	dirent = (struct ext4_dir_entry *) bh->b_data;
+	/* Determine whether or not we have an index block */
+	if (is_dx(inode)) {
+		if (block == 0)
+			is_dx_block = 1;
+		else if (ext4_rec_len_from_disk(dirent->rec_len,
+						inode->i_sb->s_blocksize) ==
+			 inode->i_sb->s_blocksize)
+			is_dx_block = 1;
+	}
+	if (!is_dx_block && type == INDEX) {
+		ext4_error_inode(inode, func, line, block,
+		       "directory leaf block found instead of index block");
+		brelse(bh);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+	if (!ext4_has_metadata_csum(inode->i_sb) ||
+	    buffer_verified(bh))
+		return bh;
+
+	/*
+	 * An empty leaf block can get mistaken for a index block; for
+	 * this reason, we can only check the index checksum when the
+	 * caller is sure it should be an index block.
+	 */
+	if (is_dx_block && type == INDEX) {
+		if (ext4_dx_csum_verify(inode, dirent) &&
+		    !ext4_simulate_fail(inode->i_sb, EXT4_SIM_DIRBLOCK_CRC))
+			set_buffer_verified(bh);
+		else {
+			ext4_error_inode_err(inode, func, line, block,
+					     EFSBADCRC,
+					     "Directory index failed checksum");
+			brelse(bh);
+			return ERR_PTR(-EFSBADCRC);
+		}
+	}
+	if (!is_dx_block) {
+		if (ext4_dirblock_csum_verify(inode, bh) &&
+		    !ext4_simulate_fail(inode->i_sb, EXT4_SIM_DIRBLOCK_CRC))
+			set_buffer_verified(bh);
+		else {
+			ext4_error_inode_err(inode, func, line, block,
+					     EFSBADCRC,
+					     "Directory block failed checksum");
+			brelse(bh);
+			return ERR_PTR(-EFSBADCRC);
+		}
+	}
+	return bh;
+}
+
+#ifndef assert
+#define assert(test) J_ASSERT(test)
+#endif
+
+#ifdef DX_DEBUG
+#define dxtrace(command) command
+#else
+#define dxtrace(command)
+#endif
+
+struct fake_dirent
+{
+	__le32 inode;
+	__le16 rec_len;
+	u8 name_len;
+	u8 file_type;
+};
+
+struct dx_countlimit
+{
+	__le16 limit;
+	__le16 count;
+};
+
+struct dx_entry
+{
+	__le32 hash;
+	__le32 block;
+};
+
+/*
+ * dx_root_info is laid out so that if it should somehow get overlaid by a
+ * dirent the two low bits of the hash version will be zero.  Therefore, the
+ * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
+ */
+
+struct dx_root
+{
+	struct fake_dirent dot;
+	char dot_name[4];
+	struct fake_dirent dotdot;
+	char dotdot_name[4];
+	struct dx_root_info
+	{
+		__le32 reserved_zero;
+		u8 hash_version;
+		u8 info_length; /* 8 */
+		u8 indirect_levels;
+		u8 unused_flags;
+	}
+	info;
+	struct dx_entry	entries[];
+};
+
+struct dx_node
+{
+	struct fake_dirent fake;
+	struct dx_entry	entries[];
+};
+
+
+struct dx_frame
+{
+	struct buffer_head *bh;
+	struct dx_entry *entries;
+	struct dx_entry *at;
+};
+
+struct dx_map_entry
+{
+	u32 hash;
+	u16 offs;
+	u16 size;
+};
+
+/*
+ * This goes at the end of each htree block.
+ */
+struct dx_tail {
+	u32 dt_reserved;
+	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
+};
+
+static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
+static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
+static inline unsigned dx_get_hash(struct dx_entry *entry);
+static void dx_set_hash(struct dx_entry *entry, unsigned value);
+static unsigned dx_get_count(struct dx_entry *entries);
+static unsigned dx_get_limit(struct dx_entry *entries);
+static void dx_set_count(struct dx_entry *entries, unsigned value);
+static void dx_set_limit(struct dx_entry *entries, unsigned value);
+static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
+static unsigned dx_node_limit(struct inode *dir);
+static struct dx_frame *dx_probe(struct ext4_filename *fname,
+				 struct inode *dir,
+				 struct dx_hash_info *hinfo,
+				 struct dx_frame *frame);
+static void dx_release(struct dx_frame *frames);
+static int dx_make_map(struct inode *dir, struct buffer_head *bh,
+		       struct dx_hash_info *hinfo,
+		       struct dx_map_entry *map_tail);
+static void dx_sort_map(struct dx_map_entry *map, unsigned count);
+static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
+		struct dx_map_entry *offsets, int count, unsigned blocksize);
+static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
+static void dx_insert_block(struct dx_frame *frame,
+					u32 hash, ext4_lblk_t block);
+static int ext4_htree_next_block(struct inode *dir, __u32 hash,
+				 struct dx_frame *frame,
+				 struct dx_frame *frames,
+				 __u32 *start_hash);
+static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
+		struct ext4_filename *fname,
+		struct ext4_dir_entry_2 **res_dir);
+static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
+			     struct inode *dir, struct inode *inode);
+
+/* checksumming functions */
+void ext4_initialize_dirent_tail(struct buffer_head *bh,
+				 unsigned int blocksize)
+{
+	struct ext4_dir_entry_tail *t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
+
+	memset(t, 0, sizeof(struct ext4_dir_entry_tail));
+	t->det_rec_len = ext4_rec_len_to_disk(
+			sizeof(struct ext4_dir_entry_tail), blocksize);
+	t->det_reserved_ft = EXT4_FT_DIR_CSUM;
+}
+
+/* Walk through a dirent block to find a checksum "dirent" at the tail */
+static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
+						   struct buffer_head *bh)
+{
+	struct ext4_dir_entry_tail *t;
+	int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
+
+#ifdef PARANOID
+	struct ext4_dir_entry *d, *top;
+
+	d = (struct ext4_dir_entry *)bh->b_data;
+	top = (struct ext4_dir_entry *)(bh->b_data +
+		(blocksize - sizeof(struct ext4_dir_entry_tail)));
+	while (d < top && ext4_rec_len_from_disk(d->rec_len, blocksize))
+		d = (struct ext4_dir_entry *)(((void *)d) +
+		    ext4_rec_len_from_disk(d->rec_len, blocksize));
+
+	if (d != top)
+		return NULL;
+
+	t = (struct ext4_dir_entry_tail *)d;
+#else
+	t = EXT4_DIRENT_TAIL(bh->b_data, EXT4_BLOCK_SIZE(inode->i_sb));
+#endif
+
+	if (t->det_reserved_zero1 ||
+	    (ext4_rec_len_from_disk(t->det_rec_len, blocksize) !=
+	     sizeof(struct ext4_dir_entry_tail)) ||
+	    t->det_reserved_zero2 ||
+	    t->det_reserved_ft != EXT4_FT_DIR_CSUM)
+		return NULL;
+
+	return t;
+}
+
+static __le32 ext4_dirblock_csum(struct inode *inode, void *dirent, int size)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	__u32 csum;
+
+	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
+	return cpu_to_le32(csum);
+}
+
+#define warn_no_space_for_csum(inode)					\
+	__warn_no_space_for_csum((inode), __func__, __LINE__)
+
+static void __warn_no_space_for_csum(struct inode *inode, const char *func,
+				     unsigned int line)
+{
+	__ext4_warning_inode(inode, func, line,
+		"No space for directory leaf checksum. Please run e2fsck -D.");
+}
+
+int ext4_dirblock_csum_verify(struct inode *inode, struct buffer_head *bh)
+{
+	struct ext4_dir_entry_tail *t;
+
+	if (!ext4_has_metadata_csum(inode->i_sb))
+		return 1;
+
+	t = get_dirent_tail(inode, bh);
+	if (!t) {
+		warn_no_space_for_csum(inode);
+		return 0;
+	}
+
+	if (t->det_checksum != ext4_dirblock_csum(inode, bh->b_data,
+						  (char *)t - bh->b_data))
+		return 0;
+
+	return 1;
+}
+
+static void ext4_dirblock_csum_set(struct inode *inode,
+				 struct buffer_head *bh)
+{
+	struct ext4_dir_entry_tail *t;
+
+	if (!ext4_has_metadata_csum(inode->i_sb))
+		return;
+
+	t = get_dirent_tail(inode, bh);
+	if (!t) {
+		warn_no_space_for_csum(inode);
+		return;
+	}
+
+	t->det_checksum = ext4_dirblock_csum(inode, bh->b_data,
+					     (char *)t - bh->b_data);
+}
+
+int ext4_handle_dirty_dirblock(handle_t *handle,
+			       struct inode *inode,
+			       struct buffer_head *bh)
+{
+	ext4_dirblock_csum_set(inode, bh);
+	return ext4_handle_dirty_metadata(handle, inode, bh);
+}
+
+static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
+					       struct ext4_dir_entry *dirent,
+					       int *offset)
+{
+	struct ext4_dir_entry *dp;
+	struct dx_root_info *root;
+	int count_offset;
+	int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
+	unsigned int rlen = ext4_rec_len_from_disk(dirent->rec_len, blocksize);
+
+	if (rlen == blocksize)
+		count_offset = 8;
+	else if (rlen == 12) {
+		dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
+		if (ext4_rec_len_from_disk(dp->rec_len, blocksize) != blocksize - 12)
+			return NULL;
+		root = (struct dx_root_info *)(((void *)dp + 12));
+		if (root->reserved_zero ||
+		    root->info_length != sizeof(struct dx_root_info))
+			return NULL;
+		count_offset = 32;
+	} else
+		return NULL;
+
+	if (offset)
+		*offset = count_offset;
+	return (struct dx_countlimit *)(((void *)dirent) + count_offset);
+}
+
+static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
+			   int count_offset, int count, struct dx_tail *t)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	__u32 csum;
+	int size;
+	__u32 dummy_csum = 0;
+	int offset = offsetof(struct dx_tail, dt_checksum);
+
+	size = count_offset + (count * sizeof(struct dx_entry));
+	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
+	csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
+	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
+
+	return cpu_to_le32(csum);
+}
+
+static int ext4_dx_csum_verify(struct inode *inode,
+			       struct ext4_dir_entry *dirent)
+{
+	struct dx_countlimit *c;
+	struct dx_tail *t;
+	int count_offset, limit, count;
+
+	if (!ext4_has_metadata_csum(inode->i_sb))
+		return 1;
+
+	c = get_dx_countlimit(inode, dirent, &count_offset);
+	if (!c) {
+		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
+		return 0;
+	}
+	limit = le16_to_cpu(c->limit);
+	count = le16_to_cpu(c->count);
+	if (count_offset + (limit * sizeof(struct dx_entry)) >
+	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
+		warn_no_space_for_csum(inode);
+		return 0;
+	}
+	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
+
+	if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
+					    count, t))
+		return 0;
+	return 1;
+}
+
+static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
+{
+	struct dx_countlimit *c;
+	struct dx_tail *t;
+	int count_offset, limit, count;
+
+	if (!ext4_has_metadata_csum(inode->i_sb))
+		return;
+
+	c = get_dx_countlimit(inode, dirent, &count_offset);
+	if (!c) {
+		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
+		return;
+	}
+	limit = le16_to_cpu(c->limit);
+	count = le16_to_cpu(c->count);
+	if (count_offset + (limit * sizeof(struct dx_entry)) >
+	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
+		warn_no_space_for_csum(inode);
+		return;
+	}
+	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
+
+	t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
+}
+
+static inline int ext4_handle_dirty_dx_node(handle_t *handle,
+					    struct inode *inode,
+					    struct buffer_head *bh)
+{
+	ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
+	return ext4_handle_dirty_metadata(handle, inode, bh);
+}
+
+/*
+ * p is at least 6 bytes before the end of page
+ */
+static inline struct ext4_dir_entry_2 *
+ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
+{
+	return (struct ext4_dir_entry_2 *)((char *)p +
+		ext4_rec_len_from_disk(p->rec_len, blocksize));
+}
+
+/*
+ * Future: use high four bits of block for coalesce-on-delete flags
+ * Mask them off for now.
+ */
+
+static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
+{
+	return le32_to_cpu(entry->block) & 0x0fffffff;
+}
+
+static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
+{
+	entry->block = cpu_to_le32(value);
+}
+
+static inline unsigned dx_get_hash(struct dx_entry *entry)
+{
+	return le32_to_cpu(entry->hash);
+}
+
+static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
+{
+	entry->hash = cpu_to_le32(value);
+}
+
+static inline unsigned dx_get_count(struct dx_entry *entries)
+{
+	return le16_to_cpu(((struct dx_countlimit *) entries)->count);
+}
+
+static inline unsigned dx_get_limit(struct dx_entry *entries)
+{
+	return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
+}
+
+static inline void dx_set_count(struct dx_entry *entries, unsigned value)
+{
+	((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
+}
+
+static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
+{
+	((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
+}
+
+static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
+{
+	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
+		EXT4_DIR_REC_LEN(2) - infosize;
+
+	if (ext4_has_metadata_csum(dir->i_sb))
+		entry_space -= sizeof(struct dx_tail);
+	return entry_space / sizeof(struct dx_entry);
+}
+
+static inline unsigned dx_node_limit(struct inode *dir)
+{
+	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
+
+	if (ext4_has_metadata_csum(dir->i_sb))
+		entry_space -= sizeof(struct dx_tail);
+	return entry_space / sizeof(struct dx_entry);
+}
+
+/*
+ * Debug
+ */
+#ifdef DX_DEBUG
+static void dx_show_index(char * label, struct dx_entry *entries)
+{
+	int i, n = dx_get_count (entries);
+	printk(KERN_DEBUG "%s index", label);
+	for (i = 0; i < n; i++) {
+		printk(KERN_CONT " %x->%lu",
+		       i ? dx_get_hash(entries + i) : 0,
+		       (unsigned long)dx_get_block(entries + i));
+	}
+	printk(KERN_CONT "\n");
+}
+
+struct stats
+{
+	unsigned names;
+	unsigned space;
+	unsigned bcount;
+};
+
+static struct stats dx_show_leaf(struct inode *dir,
+				struct dx_hash_info *hinfo,
+				struct ext4_dir_entry_2 *de,
+				int size, int show_names)
+{
+	unsigned names = 0, space = 0;
+	char *base = (char *) de;
+	struct dx_hash_info h = *hinfo;
+
+	printk("names: ");
+	while ((char *) de < base + size)
+	{
+		if (de->inode)
+		{
+			if (show_names)
+			{
+#ifdef CONFIG_FS_ENCRYPTION
+				int len;
+				char *name;
+				struct fscrypt_str fname_crypto_str =
+					FSTR_INIT(NULL, 0);
+				int res = 0;
+
+				name  = de->name;
+				len = de->name_len;
+				if (IS_ENCRYPTED(dir))
+					res = fscrypt_get_encryption_info(dir);
+				if (res) {
+					printk(KERN_WARNING "Error setting up"
+					       " fname crypto: %d\n", res);
+				}
+				if (!fscrypt_has_encryption_key(dir)) {
+					/* Directory is not encrypted */
+					ext4fs_dirhash(dir, de->name,
+						de->name_len, &h);
+					printk("%*.s:(U)%x.%u ", len,
+					       name, h.hash,
+					       (unsigned) ((char *) de
+							   - base));
+				} else {
+					struct fscrypt_str de_name =
+						FSTR_INIT(name, len);
+
+					/* Directory is encrypted */
+					res = fscrypt_fname_alloc_buffer(
+						len, &fname_crypto_str);
+					if (res)
+						printk(KERN_WARNING "Error "
+							"allocating crypto "
+							"buffer--skipping "
+							"crypto\n");
+					res = fscrypt_fname_disk_to_usr(dir,
+						0, 0, &de_name,
+						&fname_crypto_str);
+					if (res) {
+						printk(KERN_WARNING "Error "
+							"converting filename "
+							"from disk to usr"
+							"\n");
+						name = "??";
+						len = 2;
+					} else {
+						name = fname_crypto_str.name;
+						len = fname_crypto_str.len;
+					}
+					ext4fs_dirhash(dir, de->name,
+						       de->name_len, &h);
+					printk("%*.s:(E)%x.%u ", len, name,
+					       h.hash, (unsigned) ((char *) de
+								   - base));
+					fscrypt_fname_free_buffer(
+							&fname_crypto_str);
+				}
+#else
+				int len = de->name_len;
+				char *name = de->name;
+				ext4fs_dirhash(dir, de->name, de->name_len, &h);
+				printk("%*.s:%x.%u ", len, name, h.hash,
+				       (unsigned) ((char *) de - base));
+#endif
+			}
+			space += EXT4_DIR_REC_LEN(de->name_len);
+			names++;
+		}
+		de = ext4_next_entry(de, size);
+	}
+	printk(KERN_CONT "(%i)\n", names);
+	return (struct stats) { names, space, 1 };
+}
+
+struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
+			     struct dx_entry *entries, int levels)
+{
+	unsigned blocksize = dir->i_sb->s_blocksize;
+	unsigned count = dx_get_count(entries), names = 0, space = 0, i;
+	unsigned bcount = 0;
+	struct buffer_head *bh;
+	printk("%i indexed blocks...\n", count);
+	for (i = 0; i < count; i++, entries++)
+	{
+		ext4_lblk_t block = dx_get_block(entries);
+		ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
+		u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
+		struct stats stats;
+		printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
+		bh = ext4_bread(NULL,dir, block, 0);
+		if (!bh || IS_ERR(bh))
+			continue;
+		stats = levels?
+		   dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
+		   dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
+			bh->b_data, blocksize, 0);
+		names += stats.names;
+		space += stats.space;
+		bcount += stats.bcount;
+		brelse(bh);
+	}
+	if (bcount)
+		printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
+		       levels ? "" : "   ", names, space/bcount,
+		       (space/bcount)*100/blocksize);
+	return (struct stats) { names, space, bcount};
+}
+#endif /* DX_DEBUG */
+
+/*
+ * Probe for a directory leaf block to search.
+ *
+ * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
+ * error in the directory index, and the caller should fall back to
+ * searching the directory normally.  The callers of dx_probe **MUST**
+ * check for this error code, and make sure it never gets reflected
+ * back to userspace.
+ */
+static struct dx_frame *
+dx_probe(struct ext4_filename *fname, struct inode *dir,
+	 struct dx_hash_info *hinfo, struct dx_frame *frame_in)
+{
+	unsigned count, indirect, level, i;
+	struct dx_entry *at, *entries, *p, *q, *m;
+	struct dx_root *root;
+	struct dx_frame *frame = frame_in;
+	struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
+	u32 hash;
+	ext4_lblk_t block;
+	ext4_lblk_t blocks[EXT4_HTREE_LEVEL];
+
+	memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
+	frame->bh = ext4_read_dirblock(dir, 0, INDEX);
+	if (IS_ERR(frame->bh))
+		return (struct dx_frame *) frame->bh;
+
+	root = (struct dx_root *) frame->bh->b_data;
+	if (root->info.hash_version != DX_HASH_TEA &&
+	    root->info.hash_version != DX_HASH_HALF_MD4 &&
+	    root->info.hash_version != DX_HASH_LEGACY) {
+		ext4_warning_inode(dir, "Unrecognised inode hash code %u",
+				   root->info.hash_version);
+		goto fail;
+	}
+	if (fname)
+		hinfo = &fname->hinfo;
+	hinfo->hash_version = root->info.hash_version;
+	if (hinfo->hash_version <= DX_HASH_TEA)
+		hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
+	hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+	if (fname && fname_name(fname))
+		ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo);
+	hash = hinfo->hash;
+
+	if (root->info.unused_flags & 1) {
+		ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
+				   root->info.unused_flags);
+		goto fail;
+	}
+
+	indirect = root->info.indirect_levels;
+	if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
+		ext4_warning(dir->i_sb,
+			     "Directory (ino: %lu) htree depth %#06x exceed"
+			     "supported value", dir->i_ino,
+			     ext4_dir_htree_level(dir->i_sb));
+		if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
+			ext4_warning(dir->i_sb, "Enable large directory "
+						"feature to access it");
+		}
+		goto fail;
+	}
+
+	entries = (struct dx_entry *)(((char *)&root->info) +
+				      root->info.info_length);
+
+	if (dx_get_limit(entries) != dx_root_limit(dir,
+						   root->info.info_length)) {
+		ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
+				   dx_get_limit(entries),
+				   dx_root_limit(dir, root->info.info_length));
+		goto fail;
+	}
+
+	dxtrace(printk("Look up %x", hash));
+	level = 0;
+	blocks[0] = 0;
+	while (1) {
+		count = dx_get_count(entries);
+		if (!count || count > dx_get_limit(entries)) {
+			ext4_warning_inode(dir,
+					   "dx entry: count %u beyond limit %u",
+					   count, dx_get_limit(entries));
+			goto fail;
+		}
+
+		p = entries + 1;
+		q = entries + count - 1;
+		while (p <= q) {
+			m = p + (q - p) / 2;
+			dxtrace(printk(KERN_CONT "."));
+			if (dx_get_hash(m) > hash)
+				q = m - 1;
+			else
+				p = m + 1;
+		}
+
+		if (0) { // linear search cross check
+			unsigned n = count - 1;
+			at = entries;
+			while (n--)
+			{
+				dxtrace(printk(KERN_CONT ","));
+				if (dx_get_hash(++at) > hash)
+				{
+					at--;
+					break;
+				}
+			}
+			assert (at == p - 1);
+		}
+
+		at = p - 1;
+		dxtrace(printk(KERN_CONT " %x->%u\n",
+			       at == entries ? 0 : dx_get_hash(at),
+			       dx_get_block(at)));
+		frame->entries = entries;
+		frame->at = at;
+
+		block = dx_get_block(at);
+		for (i = 0; i <= level; i++) {
+			if (blocks[i] == block) {
+				ext4_warning_inode(dir,
+					"dx entry: tree cycle block %u points back to block %u",
+					blocks[level], block);
+				goto fail;
+			}
+		}
+		if (++level > indirect)
+			return frame;
+		blocks[level] = block;
+		frame++;
+		frame->bh = ext4_read_dirblock(dir, block, INDEX);
+		if (IS_ERR(frame->bh)) {
+			ret_err = (struct dx_frame *) frame->bh;
+			frame->bh = NULL;
+			goto fail;
+		}
+
+		entries = ((struct dx_node *) frame->bh->b_data)->entries;
+
+		if (dx_get_limit(entries) != dx_node_limit(dir)) {
+			ext4_warning_inode(dir,
+				"dx entry: limit %u != node limit %u",
+				dx_get_limit(entries), dx_node_limit(dir));
+			goto fail;
+		}
+	}
+fail:
+	while (frame >= frame_in) {
+		brelse(frame->bh);
+		frame--;
+	}
+
+	if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
+		ext4_warning_inode(dir,
+			"Corrupt directory, running e2fsck is recommended");
+	return ret_err;
+}
+
+static void dx_release(struct dx_frame *frames)
+{
+	struct dx_root_info *info;
+	int i;
+	unsigned int indirect_levels;
+
+	if (frames[0].bh == NULL)
+		return;
+
+	info = &((struct dx_root *)frames[0].bh->b_data)->info;
+	/* save local copy, "info" may be freed after brelse() */
+	indirect_levels = info->indirect_levels;
+	for (i = 0; i <= indirect_levels; i++) {
+		if (frames[i].bh == NULL)
+			break;
+		brelse(frames[i].bh);
+		frames[i].bh = NULL;
+	}
+}
+
+/*
+ * This function increments the frame pointer to search the next leaf
+ * block, and reads in the necessary intervening nodes if the search
+ * should be necessary.  Whether or not the search is necessary is
+ * controlled by the hash parameter.  If the hash value is even, then
+ * the search is only continued if the next block starts with that
+ * hash value.  This is used if we are searching for a specific file.
+ *
+ * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
+ *
+ * This function returns 1 if the caller should continue to search,
+ * or 0 if it should not.  If there is an error reading one of the
+ * index blocks, it will a negative error code.
+ *
+ * If start_hash is non-null, it will be filled in with the starting
+ * hash of the next page.
+ */
+static int ext4_htree_next_block(struct inode *dir, __u32 hash,
+				 struct dx_frame *frame,
+				 struct dx_frame *frames,
+				 __u32 *start_hash)
+{
+	struct dx_frame *p;
+	struct buffer_head *bh;
+	int num_frames = 0;
+	__u32 bhash;
+
+	p = frame;
+	/*
+	 * Find the next leaf page by incrementing the frame pointer.
+	 * If we run out of entries in the interior node, loop around and
+	 * increment pointer in the parent node.  When we break out of
+	 * this loop, num_frames indicates the number of interior
+	 * nodes need to be read.
+	 */
+	while (1) {
+		if (++(p->at) < p->entries + dx_get_count(p->entries))
+			break;
+		if (p == frames)
+			return 0;
+		num_frames++;
+		p--;
+	}
+
+	/*
+	 * If the hash is 1, then continue only if the next page has a
+	 * continuation hash of any value.  This is used for readdir
+	 * handling.  Otherwise, check to see if the hash matches the
+	 * desired continuation hash.  If it doesn't, return since
+	 * there's no point to read in the successive index pages.
+	 */
+	bhash = dx_get_hash(p->at);
+	if (start_hash)
+		*start_hash = bhash;
+	if ((hash & 1) == 0) {
+		if ((bhash & ~1) != hash)
+			return 0;
+	}
+	/*
+	 * If the hash is HASH_NB_ALWAYS, we always go to the next
+	 * block so no check is necessary
+	 */
+	while (num_frames--) {
+		bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
+		if (IS_ERR(bh))
+			return PTR_ERR(bh);
+		p++;
+		brelse(p->bh);
+		p->bh = bh;
+		p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
+	}
+	return 1;
+}
+
+
+/*
+ * This function fills a red-black tree with information from a
+ * directory block.  It returns the number directory entries loaded
+ * into the tree.  If there is an error it is returned in err.
+ */
+static int htree_dirblock_to_tree(struct file *dir_file,
+				  struct inode *dir, ext4_lblk_t block,
+				  struct dx_hash_info *hinfo,
+				  __u32 start_hash, __u32 start_minor_hash)
+{
+	struct buffer_head *bh;
+	struct ext4_dir_entry_2 *de, *top;
+	int err = 0, count = 0;
+	struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
+
+	dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
+							(unsigned long)block));
+	bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	de = (struct ext4_dir_entry_2 *) bh->b_data;
+	top = (struct ext4_dir_entry_2 *) ((char *) de +
+					   dir->i_sb->s_blocksize -
+					   EXT4_DIR_REC_LEN(0));
+	/* Check if the directory is encrypted */
+	if (IS_ENCRYPTED(dir)) {
+		err = fscrypt_get_encryption_info(dir);
+		if (err < 0) {
+			brelse(bh);
+			return err;
+		}
+		err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN,
+						 &fname_crypto_str);
+		if (err < 0) {
+			brelse(bh);
+			return err;
+		}
+	}
+
+	for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+				bh->b_data, bh->b_size,
+				(block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
+					 + ((char *)de - bh->b_data))) {
+			/* silently ignore the rest of the block */
+			break;
+		}
+		ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
+		if ((hinfo->hash < start_hash) ||
+		    ((hinfo->hash == start_hash) &&
+		     (hinfo->minor_hash < start_minor_hash)))
+			continue;
+		if (de->inode == 0)
+			continue;
+		if (!IS_ENCRYPTED(dir)) {
+			tmp_str.name = de->name;
+			tmp_str.len = de->name_len;
+			err = ext4_htree_store_dirent(dir_file,
+				   hinfo->hash, hinfo->minor_hash, de,
+				   &tmp_str);
+		} else {
+			int save_len = fname_crypto_str.len;
+			struct fscrypt_str de_name = FSTR_INIT(de->name,
+								de->name_len);
+
+			/* Directory is encrypted */
+			err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
+					hinfo->minor_hash, &de_name,
+					&fname_crypto_str);
+			if (err) {
+				count = err;
+				goto errout;
+			}
+			err = ext4_htree_store_dirent(dir_file,
+				   hinfo->hash, hinfo->minor_hash, de,
+					&fname_crypto_str);
+			fname_crypto_str.len = save_len;
+		}
+		if (err != 0) {
+			count = err;
+			goto errout;
+		}
+		count++;
+	}
+errout:
+	brelse(bh);
+	fscrypt_fname_free_buffer(&fname_crypto_str);
+	return count;
+}
+
+
+/*
+ * This function fills a red-black tree with information from a
+ * directory.  We start scanning the directory in hash order, starting
+ * at start_hash and start_minor_hash.
+ *
+ * This function returns the number of entries inserted into the tree,
+ * or a negative error code.
+ */
+int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
+			 __u32 start_minor_hash, __u32 *next_hash)
+{
+	struct dx_hash_info hinfo;
+	struct ext4_dir_entry_2 *de;
+	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+	struct inode *dir;
+	ext4_lblk_t block;
+	int count = 0;
+	int ret, err;
+	__u32 hashval;
+	struct fscrypt_str tmp_str;
+
+	dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
+		       start_hash, start_minor_hash));
+	dir = file_inode(dir_file);
+	if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
+		hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
+		if (hinfo.hash_version <= DX_HASH_TEA)
+			hinfo.hash_version +=
+				EXT4_SB(dir->i_sb)->s_hash_unsigned;
+		hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+		if (ext4_has_inline_data(dir)) {
+			int has_inline_data = 1;
+			count = ext4_inlinedir_to_tree(dir_file, dir, 0,
+						       &hinfo, start_hash,
+						       start_minor_hash,
+						       &has_inline_data);
+			if (has_inline_data) {
+				*next_hash = ~0;
+				return count;
+			}
+		}
+		count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
+					       start_hash, start_minor_hash);
+		*next_hash = ~0;
+		return count;
+	}
+	hinfo.hash = start_hash;
+	hinfo.minor_hash = 0;
+	frame = dx_probe(NULL, dir, &hinfo, frames);
+	if (IS_ERR(frame))
+		return PTR_ERR(frame);
+
+	/* Add '.' and '..' from the htree header */
+	if (!start_hash && !start_minor_hash) {
+		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
+		tmp_str.name = de->name;
+		tmp_str.len = de->name_len;
+		err = ext4_htree_store_dirent(dir_file, 0, 0,
+					      de, &tmp_str);
+		if (err != 0)
+			goto errout;
+		count++;
+	}
+	if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
+		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
+		de = ext4_next_entry(de, dir->i_sb->s_blocksize);
+		tmp_str.name = de->name;
+		tmp_str.len = de->name_len;
+		err = ext4_htree_store_dirent(dir_file, 2, 0,
+					      de, &tmp_str);
+		if (err != 0)
+			goto errout;
+		count++;
+	}
+
+	while (1) {
+		if (fatal_signal_pending(current)) {
+			err = -ERESTARTSYS;
+			goto errout;
+		}
+		cond_resched();
+		block = dx_get_block(frame->at);
+		ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
+					     start_hash, start_minor_hash);
+		if (ret < 0) {
+			err = ret;
+			goto errout;
+		}
+		count += ret;
+		hashval = ~0;
+		ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
+					    frame, frames, &hashval);
+		*next_hash = hashval;
+		if (ret < 0) {
+			err = ret;
+			goto errout;
+		}
+		/*
+		 * Stop if:  (a) there are no more entries, or
+		 * (b) we have inserted at least one entry and the
+		 * next hash value is not a continuation
+		 */
+		if ((ret == 0) ||
+		    (count && ((hashval & 1) == 0)))
+			break;
+	}
+	dx_release(frames);
+	dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
+		       "next hash: %x\n", count, *next_hash));
+	return count;
+errout:
+	dx_release(frames);
+	return (err);
+}
+
+static inline int search_dirblock(struct buffer_head *bh,
+				  struct inode *dir,
+				  struct ext4_filename *fname,
+				  unsigned int offset,
+				  struct ext4_dir_entry_2 **res_dir)
+{
+	return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
+			       fname, offset, res_dir);
+}
+
+/*
+ * Directory block splitting, compacting
+ */
+
+/*
+ * Create map of hash values, offsets, and sizes, stored at end of block.
+ * Returns number of entries mapped.
+ */
+static int dx_make_map(struct inode *dir, struct buffer_head *bh,
+		       struct dx_hash_info *hinfo,
+		       struct dx_map_entry *map_tail)
+{
+	int count = 0;
+	struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)bh->b_data;
+	unsigned int buflen = bh->b_size;
+	char *base = bh->b_data;
+	struct dx_hash_info h = *hinfo;
+	int blocksize = EXT4_BLOCK_SIZE(dir->i_sb);
+
+	if (ext4_has_metadata_csum(dir->i_sb))
+		buflen -= sizeof(struct ext4_dir_entry_tail);
+
+	while ((char *) de < base + buflen) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh, base, buflen,
+					 ((char *)de) - base))
+			return -EFSCORRUPTED;
+		if (de->name_len && de->inode) {
+			ext4fs_dirhash(dir, de->name, de->name_len, &h);
+			map_tail--;
+			map_tail->hash = h.hash;
+			map_tail->offs = ((char *) de - base)>>2;
+			map_tail->size = ext4_rec_len_from_disk(de->rec_len,
+								blocksize);
+			count++;
+			cond_resched();
+		}
+		de = ext4_next_entry(de, blocksize);
+	}
+	return count;
+}
+
+/* Sort map by hash value */
+static void dx_sort_map (struct dx_map_entry *map, unsigned count)
+{
+	struct dx_map_entry *p, *q, *top = map + count - 1;
+	int more;
+	/* Combsort until bubble sort doesn't suck */
+	while (count > 2) {
+		count = count*10/13;
+		if (count - 9 < 2) /* 9, 10 -> 11 */
+			count = 11;
+		for (p = top, q = p - count; q >= map; p--, q--)
+			if (p->hash < q->hash)
+				swap(*p, *q);
+	}
+	/* Garden variety bubble sort */
+	do {
+		more = 0;
+		q = top;
+		while (q-- > map) {
+			if (q[1].hash >= q[0].hash)
+				continue;
+			swap(*(q+1), *q);
+			more = 1;
+		}
+	} while(more);
+}
+
+static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
+{
+	struct dx_entry *entries = frame->entries;
+	struct dx_entry *old = frame->at, *new = old + 1;
+	int count = dx_get_count(entries);
+
+	assert(count < dx_get_limit(entries));
+	assert(old < entries + count);
+	memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
+	dx_set_hash(new, hash);
+	dx_set_block(new, block);
+	dx_set_count(entries, count + 1);
+}
+
+#ifdef CONFIG_UNICODE
+/*
+ * Test whether a case-insensitive directory entry matches the filename
+ * being searched for.  If quick is set, assume the name being looked up
+ * is already in the casefolded form.
+ *
+ * Returns: 0 if the directory entry matches, more than 0 if it
+ * doesn't match or less than zero on error.
+ */
+int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
+		    const struct qstr *entry, bool quick)
+{
+	const struct super_block *sb = parent->i_sb;
+	const struct unicode_map *um = sb->s_encoding;
+	int ret;
+
+	if (quick)
+		ret = utf8_strncasecmp_folded(um, name, entry);
+	else
+		ret = utf8_strncasecmp(um, name, entry);
+
+	if (ret < 0) {
+		/* Handle invalid character sequence as either an error
+		 * or as an opaque byte sequence.
+		 */
+		if (sb_has_strict_encoding(sb))
+			return -EINVAL;
+
+		if (name->len != entry->len)
+			return 1;
+
+		return !!memcmp(name->name, entry->name, name->len);
+	}
+
+	return ret;
+}
+
+void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
+				  struct fscrypt_str *cf_name)
+{
+	int len;
+
+	if (!IS_CASEFOLDED(dir) || !dir->i_sb->s_encoding) {
+		cf_name->name = NULL;
+		return;
+	}
+
+	cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
+	if (!cf_name->name)
+		return;
+
+	len = utf8_casefold(dir->i_sb->s_encoding,
+			    iname, cf_name->name,
+			    EXT4_NAME_LEN);
+	if (len <= 0) {
+		kfree(cf_name->name);
+		cf_name->name = NULL;
+		return;
+	}
+	cf_name->len = (unsigned) len;
+
+}
+#endif
+
+/*
+ * Test whether a directory entry matches the filename being searched for.
+ *
+ * Return: %true if the directory entry matches, otherwise %false.
+ */
+static inline bool ext4_match(const struct inode *parent,
+			      const struct ext4_filename *fname,
+			      const struct ext4_dir_entry_2 *de)
+{
+	struct fscrypt_name f;
+#ifdef CONFIG_UNICODE
+	const struct qstr entry = {.name = de->name, .len = de->name_len};
+#endif
+
+	if (!de->inode)
+		return false;
+
+	f.usr_fname = fname->usr_fname;
+	f.disk_name = fname->disk_name;
+#ifdef CONFIG_FS_ENCRYPTION
+	f.crypto_buf = fname->crypto_buf;
+#endif
+
+#ifdef CONFIG_UNICODE
+	if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent)) {
+		if (fname->cf_name.name) {
+			struct qstr cf = {.name = fname->cf_name.name,
+					  .len = fname->cf_name.len};
+			return !ext4_ci_compare(parent, &cf, &entry, true);
+		}
+		return !ext4_ci_compare(parent, fname->usr_fname, &entry,
+					false);
+	}
+#endif
+
+	return fscrypt_match_name(&f, de->name, de->name_len);
+}
+
+/*
+ * Returns 0 if not found, -1 on failure, and 1 on success
+ */
+int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
+		    struct inode *dir, struct ext4_filename *fname,
+		    unsigned int offset, struct ext4_dir_entry_2 **res_dir)
+{
+	struct ext4_dir_entry_2 * de;
+	char * dlimit;
+	int de_len;
+
+	de = (struct ext4_dir_entry_2 *)search_buf;
+	dlimit = search_buf + buf_size;
+	while ((char *) de < dlimit - EXT4_BASE_DIR_LEN) {
+		/* this code is executed quadratically often */
+		/* do minimal checking `by hand' */
+		if (de->name + de->name_len <= dlimit &&
+		    ext4_match(dir, fname, de)) {
+			/* found a match - just to be sure, do
+			 * a full check */
+			if (ext4_check_dir_entry(dir, NULL, de, bh, search_buf,
+						 buf_size, offset))
+				return -1;
+			*res_dir = de;
+			return 1;
+		}
+		/* prevent looping on a bad block */
+		de_len = ext4_rec_len_from_disk(de->rec_len,
+						dir->i_sb->s_blocksize);
+		if (de_len <= 0)
+			return -1;
+		offset += de_len;
+		de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
+	}
+	return 0;
+}
+
+static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
+			       struct ext4_dir_entry *de)
+{
+	struct super_block *sb = dir->i_sb;
+
+	if (!is_dx(dir))
+		return 0;
+	if (block == 0)
+		return 1;
+	if (de->inode == 0 &&
+	    ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
+			sb->s_blocksize)
+		return 1;
+	return 0;
+}
+
+/*
+ *	__ext4_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the cache buffer in which the entry was found, and the entry
+ * itself (as a parameter - res_dir). It does NOT read the inode of the
+ * entry - you'll have to do that yourself if you want to.
+ *
+ * The returned buffer_head has ->b_count elevated.  The caller is expected
+ * to brelse() it when appropriate.
+ */
+static struct buffer_head *__ext4_find_entry(struct inode *dir,
+					     struct ext4_filename *fname,
+					     struct ext4_dir_entry_2 **res_dir,
+					     int *inlined)
+{
+	struct super_block *sb;
+	struct buffer_head *bh_use[NAMEI_RA_SIZE];
+	struct buffer_head *bh, *ret = NULL;
+	ext4_lblk_t start, block;
+	const u8 *name = fname->usr_fname->name;
+	size_t ra_max = 0;	/* Number of bh's in the readahead
+				   buffer, bh_use[] */
+	size_t ra_ptr = 0;	/* Current index into readahead
+				   buffer */
+	ext4_lblk_t  nblocks;
+	int i, namelen, retval;
+
+	*res_dir = NULL;
+	sb = dir->i_sb;
+	namelen = fname->usr_fname->len;
+	if (namelen > EXT4_NAME_LEN)
+		return NULL;
+
+	if (ext4_has_inline_data(dir)) {
+		int has_inline_data = 1;
+		ret = ext4_find_inline_entry(dir, fname, res_dir,
+					     &has_inline_data);
+		if (inlined)
+			*inlined = has_inline_data;
+		if (has_inline_data)
+			goto cleanup_and_exit;
+	}
+
+	if ((namelen <= 2) && (name[0] == '.') &&
+	    (name[1] == '.' || name[1] == '\0')) {
+		/*
+		 * "." or ".." will only be in the first block
+		 * NFS may look up ".."; "." should be handled by the VFS
+		 */
+		block = start = 0;
+		nblocks = 1;
+		goto restart;
+	}
+	if (is_dx(dir)) {
+		ret = ext4_dx_find_entry(dir, fname, res_dir);
+		/*
+		 * On success, or if the error was file not found,
+		 * return.  Otherwise, fall back to doing a search the
+		 * old fashioned way.
+		 */
+		if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
+			goto cleanup_and_exit;
+		dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
+			       "falling back\n"));
+		ret = NULL;
+	}
+	nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
+	if (!nblocks) {
+		ret = NULL;
+		goto cleanup_and_exit;
+	}
+	start = EXT4_I(dir)->i_dir_start_lookup;
+	if (start >= nblocks)
+		start = 0;
+	block = start;
+restart:
+	do {
+		/*
+		 * We deal with the read-ahead logic here.
+		 */
+		cond_resched();
+		if (ra_ptr >= ra_max) {
+			/* Refill the readahead buffer */
+			ra_ptr = 0;
+			if (block < start)
+				ra_max = start - block;
+			else
+				ra_max = nblocks - block;
+			ra_max = min(ra_max, ARRAY_SIZE(bh_use));
+			retval = ext4_bread_batch(dir, block, ra_max,
+						  false /* wait */, bh_use);
+			if (retval) {
+				ret = ERR_PTR(retval);
+				ra_max = 0;
+				goto cleanup_and_exit;
+			}
+		}
+		if ((bh = bh_use[ra_ptr++]) == NULL)
+			goto next;
+		wait_on_buffer(bh);
+		if (!buffer_uptodate(bh)) {
+			EXT4_ERROR_INODE_ERR(dir, EIO,
+					     "reading directory lblock %lu",
+					     (unsigned long) block);
+			brelse(bh);
+			ret = ERR_PTR(-EIO);
+			goto cleanup_and_exit;
+		}
+		if (!buffer_verified(bh) &&
+		    !is_dx_internal_node(dir, block,
+					 (struct ext4_dir_entry *)bh->b_data) &&
+		    !ext4_dirblock_csum_verify(dir, bh)) {
+			EXT4_ERROR_INODE_ERR(dir, EFSBADCRC,
+					     "checksumming directory "
+					     "block %lu", (unsigned long)block);
+			brelse(bh);
+			ret = ERR_PTR(-EFSBADCRC);
+			goto cleanup_and_exit;
+		}
+		set_buffer_verified(bh);
+		i = search_dirblock(bh, dir, fname,
+			    block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
+		if (i == 1) {
+			EXT4_I(dir)->i_dir_start_lookup = block;
+			ret = bh;
+			goto cleanup_and_exit;
+		} else {
+			brelse(bh);
+			if (i < 0)
+				goto cleanup_and_exit;
+		}
+	next:
+		if (++block >= nblocks)
+			block = 0;
+	} while (block != start);
+
+	/*
+	 * If the directory has grown while we were searching, then
+	 * search the last part of the directory before giving up.
+	 */
+	block = nblocks;
+	nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
+	if (block < nblocks) {
+		start = 0;
+		goto restart;
+	}
+
+cleanup_and_exit:
+	/* Clean up the read-ahead blocks */
+	for (; ra_ptr < ra_max; ra_ptr++)
+		brelse(bh_use[ra_ptr]);
+	return ret;
+}
+
+static struct buffer_head *ext4_find_entry(struct inode *dir,
+					   const struct qstr *d_name,
+					   struct ext4_dir_entry_2 **res_dir,
+					   int *inlined)
+{
+	int err;
+	struct ext4_filename fname;
+	struct buffer_head *bh;
+
+	err = ext4_fname_setup_filename(dir, d_name, 1, &fname);
+	if (err == -ENOENT)
+		return NULL;
+	if (err)
+		return ERR_PTR(err);
+
+	bh = __ext4_find_entry(dir, &fname, res_dir, inlined);
+
+	ext4_fname_free_filename(&fname);
+	return bh;
+}
+
+static struct buffer_head *ext4_lookup_entry(struct inode *dir,
+					     struct dentry *dentry,
+					     struct ext4_dir_entry_2 **res_dir)
+{
+	int err;
+	struct ext4_filename fname;
+	struct buffer_head *bh;
+
+	err = ext4_fname_prepare_lookup(dir, dentry, &fname);
+	if (err == -ENOENT)
+		return NULL;
+	if (err)
+		return ERR_PTR(err);
+
+	bh = __ext4_find_entry(dir, &fname, res_dir, NULL);
+
+	ext4_fname_free_filename(&fname);
+	return bh;
+}
+
+static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
+			struct ext4_filename *fname,
+			struct ext4_dir_entry_2 **res_dir)
+{
+	struct super_block * sb = dir->i_sb;
+	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+	struct buffer_head *bh;
+	ext4_lblk_t block;
+	int retval;
+
+#ifdef CONFIG_FS_ENCRYPTION
+	*res_dir = NULL;
+#endif
+	frame = dx_probe(fname, dir, NULL, frames);
+	if (IS_ERR(frame))
+		return (struct buffer_head *) frame;
+	do {
+		block = dx_get_block(frame->at);
+		bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
+		if (IS_ERR(bh))
+			goto errout;
+
+		retval = search_dirblock(bh, dir, fname,
+					 block << EXT4_BLOCK_SIZE_BITS(sb),
+					 res_dir);
+		if (retval == 1)
+			goto success;
+		brelse(bh);
+		if (retval == -1) {
+			bh = ERR_PTR(ERR_BAD_DX_DIR);
+			goto errout;
+		}
+
+		/* Check to see if we should continue to search */
+		retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
+					       frames, NULL);
+		if (retval < 0) {
+			ext4_warning_inode(dir,
+				"error %d reading directory index block",
+				retval);
+			bh = ERR_PTR(retval);
+			goto errout;
+		}
+	} while (retval == 1);
+
+	bh = NULL;
+errout:
+	dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
+success:
+	dx_release(frames);
+	return bh;
+}
+
+static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	struct inode *inode;
+	struct ext4_dir_entry_2 *de;
+	struct buffer_head *bh;
+
+	if (dentry->d_name.len > EXT4_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	bh = ext4_lookup_entry(dir, dentry, &de);
+	if (IS_ERR(bh))
+		return ERR_CAST(bh);
+	inode = NULL;
+	if (bh) {
+		__u32 ino = le32_to_cpu(de->inode);
+		brelse(bh);
+		if (!ext4_valid_inum(dir->i_sb, ino)) {
+			EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+		if (unlikely(ino == dir->i_ino)) {
+			EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
+					 dentry);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+		inode = ext4_iget(dir->i_sb, ino, EXT4_IGET_NORMAL);
+		if (inode == ERR_PTR(-ESTALE)) {
+			EXT4_ERROR_INODE(dir,
+					 "deleted inode referenced: %u",
+					 ino);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+		if (!IS_ERR(inode) && IS_ENCRYPTED(dir) &&
+		    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
+		    !fscrypt_has_permitted_context(dir, inode)) {
+			ext4_warning(inode->i_sb,
+				     "Inconsistent encryption contexts: %lu/%lu",
+				     dir->i_ino, inode->i_ino);
+			iput(inode);
+			return ERR_PTR(-EPERM);
+		}
+	}
+
+#ifdef CONFIG_UNICODE
+	if (!inode && IS_CASEFOLDED(dir)) {
+		/* Eventually we want to call d_add_ci(dentry, NULL)
+		 * for negative dentries in the encoding case as
+		 * well.  For now, prevent the negative dentry
+		 * from being cached.
+		 */
+		return NULL;
+	}
+#endif
+	return d_splice_alias(inode, dentry);
+}
+
+
+struct dentry *ext4_get_parent(struct dentry *child)
+{
+	__u32 ino;
+	static const struct qstr dotdot = QSTR_INIT("..", 2);
+	struct ext4_dir_entry_2 * de;
+	struct buffer_head *bh;
+
+	bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
+	if (IS_ERR(bh))
+		return ERR_CAST(bh);
+	if (!bh)
+		return ERR_PTR(-ENOENT);
+	ino = le32_to_cpu(de->inode);
+	brelse(bh);
+
+	if (!ext4_valid_inum(child->d_sb, ino)) {
+		EXT4_ERROR_INODE(d_inode(child),
+				 "bad parent inode number: %u", ino);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+
+	return d_obtain_alias(ext4_iget(child->d_sb, ino, EXT4_IGET_NORMAL));
+}
+
+/*
+ * Move count entries from end of map between two memory locations.
+ * Returns pointer to last entry moved.
+ */
+static struct ext4_dir_entry_2 *
+dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
+		unsigned blocksize)
+{
+	unsigned rec_len = 0;
+
+	while (count--) {
+		struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
+						(from + (map->offs<<2));
+		rec_len = EXT4_DIR_REC_LEN(de->name_len);
+		memcpy (to, de, rec_len);
+		((struct ext4_dir_entry_2 *) to)->rec_len =
+				ext4_rec_len_to_disk(rec_len, blocksize);
+		de->inode = 0;
+		map++;
+		to += rec_len;
+	}
+	return (struct ext4_dir_entry_2 *) (to - rec_len);
+}
+
+/*
+ * Compact each dir entry in the range to the minimal rec_len.
+ * Returns pointer to last entry in range.
+ */
+static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
+{
+	struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
+	unsigned rec_len = 0;
+
+	prev = to = de;
+	while ((char*)de < base + blocksize) {
+		next = ext4_next_entry(de, blocksize);
+		if (de->inode && de->name_len) {
+			rec_len = EXT4_DIR_REC_LEN(de->name_len);
+			if (de > to)
+				memmove(to, de, rec_len);
+			to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
+			prev = to;
+			to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
+		}
+		de = next;
+	}
+	return prev;
+}
+
+/*
+ * Split a full leaf block to make room for a new dir entry.
+ * Allocate a new block, and move entries so that they are approx. equally full.
+ * Returns pointer to de in block into which the new entry will be inserted.
+ */
+static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
+			struct buffer_head **bh,struct dx_frame *frame,
+			struct dx_hash_info *hinfo)
+{
+	unsigned blocksize = dir->i_sb->s_blocksize;
+	unsigned continued;
+	int count;
+	struct buffer_head *bh2;
+	ext4_lblk_t newblock;
+	u32 hash2;
+	struct dx_map_entry *map;
+	char *data1 = (*bh)->b_data, *data2;
+	unsigned split, move, size;
+	struct ext4_dir_entry_2 *de = NULL, *de2;
+	int	csum_size = 0;
+	int	err = 0, i;
+
+	if (ext4_has_metadata_csum(dir->i_sb))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	bh2 = ext4_append(handle, dir, &newblock);
+	if (IS_ERR(bh2)) {
+		brelse(*bh);
+		*bh = NULL;
+		return (struct ext4_dir_entry_2 *) bh2;
+	}
+
+	BUFFER_TRACE(*bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, *bh);
+	if (err)
+		goto journal_error;
+
+	BUFFER_TRACE(frame->bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, frame->bh);
+	if (err)
+		goto journal_error;
+
+	data2 = bh2->b_data;
+
+	/* create map in the end of data2 block */
+	map = (struct dx_map_entry *) (data2 + blocksize);
+	count = dx_make_map(dir, *bh, hinfo, map);
+	if (count < 0) {
+		err = count;
+		goto journal_error;
+	}
+	map -= count;
+	dx_sort_map(map, count);
+	/* Ensure that neither split block is over half full */
+	size = 0;
+	move = 0;
+	for (i = count-1; i >= 0; i--) {
+		/* is more than half of this entry in 2nd half of the block? */
+		if (size + map[i].size/2 > blocksize/2)
+			break;
+		size += map[i].size;
+		move++;
+	}
+	/*
+	 * map index at which we will split
+	 *
+	 * If the sum of active entries didn't exceed half the block size, just
+	 * split it in half by count; each resulting block will have at least
+	 * half the space free.
+	 */
+	if (i > 0)
+		split = count - move;
+	else
+		split = count/2;
+
+	hash2 = map[split].hash;
+	continued = hash2 == map[split - 1].hash;
+	dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
+			(unsigned long)dx_get_block(frame->at),
+					hash2, split, count-split));
+
+	/* Fancy dance to stay within two buffers */
+	de2 = dx_move_dirents(data1, data2, map + split, count - split,
+			      blocksize);
+	de = dx_pack_dirents(data1, blocksize);
+	de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
+					   (char *) de,
+					   blocksize);
+	de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
+					    (char *) de2,
+					    blocksize);
+	if (csum_size) {
+		ext4_initialize_dirent_tail(*bh, blocksize);
+		ext4_initialize_dirent_tail(bh2, blocksize);
+	}
+
+	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
+			blocksize, 1));
+	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
+			blocksize, 1));
+
+	/* Which block gets the new entry? */
+	if (hinfo->hash >= hash2) {
+		swap(*bh, bh2);
+		de = de2;
+	}
+	dx_insert_block(frame, hash2 + continued, newblock);
+	err = ext4_handle_dirty_dirblock(handle, dir, bh2);
+	if (err)
+		goto journal_error;
+	err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
+	if (err)
+		goto journal_error;
+	brelse(bh2);
+	dxtrace(dx_show_index("frame", frame->entries));
+	return de;
+
+journal_error:
+	brelse(*bh);
+	brelse(bh2);
+	*bh = NULL;
+	ext4_std_error(dir->i_sb, err);
+	return ERR_PTR(err);
+}
+
+int ext4_find_dest_de(struct inode *dir, struct inode *inode,
+		      struct buffer_head *bh,
+		      void *buf, int buf_size,
+		      struct ext4_filename *fname,
+		      struct ext4_dir_entry_2 **dest_de)
+{
+	struct ext4_dir_entry_2 *de;
+	unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
+	int nlen, rlen;
+	unsigned int offset = 0;
+	char *top;
+
+	de = (struct ext4_dir_entry_2 *)buf;
+	top = buf + buf_size - reclen;
+	while ((char *) de <= top) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 buf, buf_size, offset))
+			return -EFSCORRUPTED;
+		if (ext4_match(dir, fname, de))
+			return -EEXIST;
+		nlen = EXT4_DIR_REC_LEN(de->name_len);
+		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
+		if ((de->inode ? rlen - nlen : rlen) >= reclen)
+			break;
+		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
+		offset += rlen;
+	}
+	if ((char *) de > top)
+		return -ENOSPC;
+
+	*dest_de = de;
+	return 0;
+}
+
+void ext4_insert_dentry(struct inode *inode,
+			struct ext4_dir_entry_2 *de,
+			int buf_size,
+			struct ext4_filename *fname)
+{
+
+	int nlen, rlen;
+
+	nlen = EXT4_DIR_REC_LEN(de->name_len);
+	rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
+	if (de->inode) {
+		struct ext4_dir_entry_2 *de1 =
+			(struct ext4_dir_entry_2 *)((char *)de + nlen);
+		de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
+		de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
+		de = de1;
+	}
+	de->file_type = EXT4_FT_UNKNOWN;
+	de->inode = cpu_to_le32(inode->i_ino);
+	ext4_set_de_type(inode->i_sb, de, inode->i_mode);
+	de->name_len = fname_len(fname);
+	memcpy(de->name, fname_name(fname), fname_len(fname));
+}
+
+/*
+ * Add a new entry into a directory (leaf) block.  If de is non-NULL,
+ * it points to a directory entry which is guaranteed to be large
+ * enough for new directory entry.  If de is NULL, then
+ * add_dirent_to_buf will attempt search the directory block for
+ * space.  It will return -ENOSPC if no space is available, and -EIO
+ * and -EEXIST if directory entry already exists.
+ */
+static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
+			     struct inode *dir,
+			     struct inode *inode, struct ext4_dir_entry_2 *de,
+			     struct buffer_head *bh)
+{
+	unsigned int	blocksize = dir->i_sb->s_blocksize;
+	int		csum_size = 0;
+	int		err, err2;
+
+	if (ext4_has_metadata_csum(inode->i_sb))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	if (!de) {
+		err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
+					blocksize - csum_size, fname, &de);
+		if (err)
+			return err;
+	}
+	BUFFER_TRACE(bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, bh);
+	if (err) {
+		ext4_std_error(dir->i_sb, err);
+		return err;
+	}
+
+	/* By now the buffer is marked for journaling */
+	ext4_insert_dentry(inode, de, blocksize, fname);
+
+	/*
+	 * XXX shouldn't update any times until successful
+	 * completion of syscall, but too many callers depend
+	 * on this.
+	 *
+	 * XXX similarly, too many callers depend on
+	 * ext4_new_inode() setting the times, but error
+	 * recovery deletes the inode, so the worst that can
+	 * happen is that the times are slightly out of date
+	 * and/or different from the directory change time.
+	 */
+	dir->i_mtime = dir->i_ctime = current_time(dir);
+	ext4_update_dx_flag(dir);
+	inode_inc_iversion(dir);
+	err2 = ext4_mark_inode_dirty(handle, dir);
+	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_dirblock(handle, dir, bh);
+	if (err)
+		ext4_std_error(dir->i_sb, err);
+	return err ? err : err2;
+}
+
+/*
+ * This converts a one block unindexed directory to a 3 block indexed
+ * directory, and adds the dentry to the indexed directory.
+ */
+static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
+			    struct inode *dir,
+			    struct inode *inode, struct buffer_head *bh)
+{
+	struct buffer_head *bh2;
+	struct dx_root	*root;
+	struct dx_frame	frames[EXT4_HTREE_LEVEL], *frame;
+	struct dx_entry *entries;
+	struct ext4_dir_entry_2	*de, *de2;
+	char		*data2, *top;
+	unsigned	len;
+	int		retval;
+	unsigned	blocksize;
+	ext4_lblk_t  block;
+	struct fake_dirent *fde;
+	int csum_size = 0;
+
+	if (ext4_has_metadata_csum(inode->i_sb))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	blocksize =  dir->i_sb->s_blocksize;
+	dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
+	BUFFER_TRACE(bh, "get_write_access");
+	retval = ext4_journal_get_write_access(handle, bh);
+	if (retval) {
+		ext4_std_error(dir->i_sb, retval);
+		brelse(bh);
+		return retval;
+	}
+	root = (struct dx_root *) bh->b_data;
+
+	/* The 0th block becomes the root, move the dirents out */
+	fde = &root->dotdot;
+	de = (struct ext4_dir_entry_2 *)((char *)fde +
+		ext4_rec_len_from_disk(fde->rec_len, blocksize));
+	if ((char *) de >= (((char *) root) + blocksize)) {
+		EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
+		brelse(bh);
+		return -EFSCORRUPTED;
+	}
+	len = ((char *) root) + (blocksize - csum_size) - (char *) de;
+
+	/* Allocate new block for the 0th block's dirents */
+	bh2 = ext4_append(handle, dir, &block);
+	if (IS_ERR(bh2)) {
+		brelse(bh);
+		return PTR_ERR(bh2);
+	}
+	ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
+	data2 = bh2->b_data;
+
+	memcpy(data2, de, len);
+	de = (struct ext4_dir_entry_2 *) data2;
+	top = data2 + len;
+	while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh2, data2, len,
+					 (data2 + (blocksize - csum_size) -
+					  (char *) de))) {
+			brelse(bh2);
+			brelse(bh);
+			return -EFSCORRUPTED;
+		}
+		de = de2;
+	}
+	de->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
+					   (char *) de, blocksize);
+
+	if (csum_size)
+		ext4_initialize_dirent_tail(bh2, blocksize);
+
+	/* Initialize the root; the dot dirents already exist */
+	de = (struct ext4_dir_entry_2 *) (&root->dotdot);
+	de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
+					   blocksize);
+	memset (&root->info, 0, sizeof(root->info));
+	root->info.info_length = sizeof(root->info);
+	root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
+	entries = root->entries;
+	dx_set_block(entries, 1);
+	dx_set_count(entries, 1);
+	dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
+
+	/* Initialize as for dx_probe */
+	fname->hinfo.hash_version = root->info.hash_version;
+	if (fname->hinfo.hash_version <= DX_HASH_TEA)
+		fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
+	fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+	ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), &fname->hinfo);
+
+	memset(frames, 0, sizeof(frames));
+	frame = frames;
+	frame->entries = entries;
+	frame->at = entries;
+	frame->bh = bh;
+
+	retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
+	if (retval)
+		goto out_frames;	
+	retval = ext4_handle_dirty_dirblock(handle, dir, bh2);
+	if (retval)
+		goto out_frames;	
+
+	de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
+	if (IS_ERR(de)) {
+		retval = PTR_ERR(de);
+		goto out_frames;
+	}
+
+	retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
+out_frames:
+	/*
+	 * Even if the block split failed, we have to properly write
+	 * out all the changes we did so far. Otherwise we can end up
+	 * with corrupted filesystem.
+	 */
+	if (retval)
+		ext4_mark_inode_dirty(handle, dir);
+	dx_release(frames);
+	brelse(bh2);
+	return retval;
+}
+
+/*
+ *	ext4_add_entry()
+ *
+ * adds a file entry to the specified directory, using the same
+ * semantics as ext4_find_entry(). It returns NULL if it failed.
+ *
+ * NOTE!! The inode part of 'de' is left at 0 - which means you
+ * may not sleep between calling this and putting something into
+ * the entry, as someone else might have used it while you slept.
+ */
+static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
+			  struct inode *inode)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+	struct buffer_head *bh = NULL;
+	struct ext4_dir_entry_2 *de;
+	struct super_block *sb;
+	struct ext4_filename fname;
+	int	retval;
+	int	dx_fallback=0;
+	unsigned blocksize;
+	ext4_lblk_t block, blocks;
+	int	csum_size = 0;
+
+	if (ext4_has_metadata_csum(inode->i_sb))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	sb = dir->i_sb;
+	blocksize = sb->s_blocksize;
+	if (!dentry->d_name.len)
+		return -EINVAL;
+
+	if (fscrypt_is_nokey_name(dentry))
+		return -ENOKEY;
+
+#ifdef CONFIG_UNICODE
+	if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) &&
+	    sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
+		return -EINVAL;
+#endif
+
+	retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
+	if (retval)
+		return retval;
+
+	if (ext4_has_inline_data(dir)) {
+		retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
+		if (retval < 0)
+			goto out;
+		if (retval == 1) {
+			retval = 0;
+			goto out;
+		}
+	}
+
+	if (is_dx(dir)) {
+		retval = ext4_dx_add_entry(handle, &fname, dir, inode);
+		if (!retval || (retval != ERR_BAD_DX_DIR))
+			goto out;
+		/* Can we just ignore htree data? */
+		if (ext4_has_metadata_csum(sb)) {
+			EXT4_ERROR_INODE(dir,
+				"Directory has corrupted htree index.");
+			retval = -EFSCORRUPTED;
+			goto out;
+		}
+		ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
+		dx_fallback++;
+		retval = ext4_mark_inode_dirty(handle, dir);
+		if (unlikely(retval))
+			goto out;
+	}
+	blocks = dir->i_size >> sb->s_blocksize_bits;
+	for (block = 0; block < blocks; block++) {
+		bh = ext4_read_dirblock(dir, block, DIRENT);
+		if (bh == NULL) {
+			bh = ext4_bread(handle, dir, block,
+					EXT4_GET_BLOCKS_CREATE);
+			goto add_to_new_block;
+		}
+		if (IS_ERR(bh)) {
+			retval = PTR_ERR(bh);
+			bh = NULL;
+			goto out;
+		}
+		retval = add_dirent_to_buf(handle, &fname, dir, inode,
+					   NULL, bh);
+		if (retval != -ENOSPC)
+			goto out;
+
+		if (blocks == 1 && !dx_fallback &&
+		    ext4_has_feature_dir_index(sb)) {
+			retval = make_indexed_dir(handle, &fname, dir,
+						  inode, bh);
+			bh = NULL; /* make_indexed_dir releases bh */
+			goto out;
+		}
+		brelse(bh);
+	}
+	bh = ext4_append(handle, dir, &block);
+add_to_new_block:
+	if (IS_ERR(bh)) {
+		retval = PTR_ERR(bh);
+		bh = NULL;
+		goto out;
+	}
+	de = (struct ext4_dir_entry_2 *) bh->b_data;
+	de->inode = 0;
+	de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
+
+	if (csum_size)
+		ext4_initialize_dirent_tail(bh, blocksize);
+
+	retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
+out:
+	ext4_fname_free_filename(&fname);
+	brelse(bh);
+	if (retval == 0)
+		ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
+	return retval;
+}
+
+/*
+ * Returns 0 for success, or a negative error value
+ */
+static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
+			     struct inode *dir, struct inode *inode)
+{
+	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+	struct dx_entry *entries, *at;
+	struct buffer_head *bh;
+	struct super_block *sb = dir->i_sb;
+	struct ext4_dir_entry_2 *de;
+	int restart;
+	int err;
+
+again:
+	restart = 0;
+	frame = dx_probe(fname, dir, NULL, frames);
+	if (IS_ERR(frame))
+		return PTR_ERR(frame);
+	entries = frame->entries;
+	at = frame->at;
+	bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT_HTREE);
+	if (IS_ERR(bh)) {
+		err = PTR_ERR(bh);
+		bh = NULL;
+		goto cleanup;
+	}
+
+	BUFFER_TRACE(bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, bh);
+	if (err)
+		goto journal_error;
+
+	err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
+	if (err != -ENOSPC)
+		goto cleanup;
+
+	err = 0;
+	/* Block full, should compress but for now just split */
+	dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
+		       dx_get_count(entries), dx_get_limit(entries)));
+	/* Need to split index? */
+	if (dx_get_count(entries) == dx_get_limit(entries)) {
+		ext4_lblk_t newblock;
+		int levels = frame - frames + 1;
+		unsigned int icount;
+		int add_level = 1;
+		struct dx_entry *entries2;
+		struct dx_node *node2;
+		struct buffer_head *bh2;
+
+		while (frame > frames) {
+			if (dx_get_count((frame - 1)->entries) <
+			    dx_get_limit((frame - 1)->entries)) {
+				add_level = 0;
+				break;
+			}
+			frame--; /* split higher index block */
+			at = frame->at;
+			entries = frame->entries;
+			restart = 1;
+		}
+		if (add_level && levels == ext4_dir_htree_level(sb)) {
+			ext4_warning(sb, "Directory (ino: %lu) index full, "
+					 "reach max htree level :%d",
+					 dir->i_ino, levels);
+			if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
+				ext4_warning(sb, "Large directory feature is "
+						 "not enabled on this "
+						 "filesystem");
+			}
+			err = -ENOSPC;
+			goto cleanup;
+		}
+		icount = dx_get_count(entries);
+		bh2 = ext4_append(handle, dir, &newblock);
+		if (IS_ERR(bh2)) {
+			err = PTR_ERR(bh2);
+			goto cleanup;
+		}
+		node2 = (struct dx_node *)(bh2->b_data);
+		entries2 = node2->entries;
+		memset(&node2->fake, 0, sizeof(struct fake_dirent));
+		node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
+							   sb->s_blocksize);
+		BUFFER_TRACE(frame->bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, frame->bh);
+		if (err)
+			goto journal_error;
+		if (!add_level) {
+			unsigned icount1 = icount/2, icount2 = icount - icount1;
+			unsigned hash2 = dx_get_hash(entries + icount1);
+			dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
+				       icount1, icount2));
+
+			BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
+			err = ext4_journal_get_write_access(handle,
+							     (frame - 1)->bh);
+			if (err)
+				goto journal_error;
+
+			memcpy((char *) entries2, (char *) (entries + icount1),
+			       icount2 * sizeof(struct dx_entry));
+			dx_set_count(entries, icount1);
+			dx_set_count(entries2, icount2);
+			dx_set_limit(entries2, dx_node_limit(dir));
+
+			/* Which index block gets the new entry? */
+			if (at - entries >= icount1) {
+				frame->at = at = at - entries - icount1 + entries2;
+				frame->entries = entries = entries2;
+				swap(frame->bh, bh2);
+			}
+			dx_insert_block((frame - 1), hash2, newblock);
+			dxtrace(dx_show_index("node", frame->entries));
+			dxtrace(dx_show_index("node",
+			       ((struct dx_node *) bh2->b_data)->entries));
+			err = ext4_handle_dirty_dx_node(handle, dir, bh2);
+			if (err)
+				goto journal_error;
+			brelse (bh2);
+			err = ext4_handle_dirty_dx_node(handle, dir,
+						   (frame - 1)->bh);
+			if (err)
+				goto journal_error;
+			err = ext4_handle_dirty_dx_node(handle, dir,
+							frame->bh);
+			if (restart || err)
+				goto journal_error;
+		} else {
+			struct dx_root *dxroot;
+			memcpy((char *) entries2, (char *) entries,
+			       icount * sizeof(struct dx_entry));
+			dx_set_limit(entries2, dx_node_limit(dir));
+
+			/* Set up root */
+			dx_set_count(entries, 1);
+			dx_set_block(entries + 0, newblock);
+			dxroot = (struct dx_root *)frames[0].bh->b_data;
+			dxroot->info.indirect_levels += 1;
+			dxtrace(printk(KERN_DEBUG
+				       "Creating %d level index...\n",
+				       dxroot->info.indirect_levels));
+			err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
+			if (err)
+				goto journal_error;
+			err = ext4_handle_dirty_dx_node(handle, dir, bh2);
+			brelse(bh2);
+			restart = 1;
+			goto journal_error;
+		}
+	}
+	de = do_split(handle, dir, &bh, frame, &fname->hinfo);
+	if (IS_ERR(de)) {
+		err = PTR_ERR(de);
+		goto cleanup;
+	}
+	err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
+	goto cleanup;
+
+journal_error:
+	ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
+cleanup:
+	brelse(bh);
+	dx_release(frames);
+	/* @restart is true means htree-path has been changed, we need to
+	 * repeat dx_probe() to find out valid htree-path
+	 */
+	if (restart && err == 0)
+		goto again;
+	return err;
+}
+
+/*
+ * ext4_generic_delete_entry deletes a directory entry by merging it
+ * with the previous entry
+ */
+int ext4_generic_delete_entry(struct inode *dir,
+			      struct ext4_dir_entry_2 *de_del,
+			      struct buffer_head *bh,
+			      void *entry_buf,
+			      int buf_size,
+			      int csum_size)
+{
+	struct ext4_dir_entry_2 *de, *pde;
+	unsigned int blocksize = dir->i_sb->s_blocksize;
+	int i;
+
+	i = 0;
+	pde = NULL;
+	de = (struct ext4_dir_entry_2 *)entry_buf;
+	while (i < buf_size - csum_size) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 entry_buf, buf_size, i))
+			return -EFSCORRUPTED;
+		if (de == de_del)  {
+			if (pde)
+				pde->rec_len = ext4_rec_len_to_disk(
+					ext4_rec_len_from_disk(pde->rec_len,
+							       blocksize) +
+					ext4_rec_len_from_disk(de->rec_len,
+							       blocksize),
+					blocksize);
+			else
+				de->inode = 0;
+			inode_inc_iversion(dir);
+			return 0;
+		}
+		i += ext4_rec_len_from_disk(de->rec_len, blocksize);
+		pde = de;
+		de = ext4_next_entry(de, blocksize);
+	}
+	return -ENOENT;
+}
+
+static int ext4_delete_entry(handle_t *handle,
+			     struct inode *dir,
+			     struct ext4_dir_entry_2 *de_del,
+			     struct buffer_head *bh)
+{
+	int err, csum_size = 0;
+
+	if (ext4_has_inline_data(dir)) {
+		int has_inline_data = 1;
+		err = ext4_delete_inline_entry(handle, dir, de_del, bh,
+					       &has_inline_data);
+		if (has_inline_data)
+			return err;
+	}
+
+	if (ext4_has_metadata_csum(dir->i_sb))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	BUFFER_TRACE(bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, bh);
+	if (unlikely(err))
+		goto out;
+
+	err = ext4_generic_delete_entry(dir, de_del, bh, bh->b_data,
+					dir->i_sb->s_blocksize, csum_size);
+	if (err)
+		goto out;
+
+	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_dirblock(handle, dir, bh);
+	if (unlikely(err))
+		goto out;
+
+	return 0;
+out:
+	if (err != -ENOENT)
+		ext4_std_error(dir->i_sb, err);
+	return err;
+}
+
+/*
+ * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2
+ * since this indicates that nlinks count was previously 1 to avoid overflowing
+ * the 16-bit i_links_count field on disk.  Directories with i_nlink == 1 mean
+ * that subdirectory link counts are not being maintained accurately.
+ *
+ * The caller has already checked for i_nlink overflow in case the DIR_LINK
+ * feature is not enabled and returned -EMLINK.  The is_dx() check is a proxy
+ * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
+ * on regular files) and to avoid creating huge/slow non-HTREE directories.
+ */
+static void ext4_inc_count(struct inode *inode)
+{
+	inc_nlink(inode);
+	if (is_dx(inode) &&
+	    (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2))
+		set_nlink(inode, 1);
+}
+
+/*
+ * If a directory had nlink == 1, then we should let it be 1. This indicates
+ * directory has >EXT4_LINK_MAX subdirs.
+ */
+static void ext4_dec_count(struct inode *inode)
+{
+	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
+		drop_nlink(inode);
+}
+
+
+/*
+ * Add non-directory inode to a directory. On success, the inode reference is
+ * consumed by dentry is instantiation. This is also indicated by clearing of
+ * *inodep pointer. On failure, the caller is responsible for dropping the
+ * inode reference in the safe context.
+ */
+static int ext4_add_nondir(handle_t *handle,
+		struct dentry *dentry, struct inode **inodep)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+	struct inode *inode = *inodep;
+	int err = ext4_add_entry(handle, dentry, inode);
+	if (!err) {
+		err = ext4_mark_inode_dirty(handle, inode);
+		if (IS_DIRSYNC(dir))
+			ext4_handle_sync(handle);
+		d_instantiate_new(dentry, inode);
+		*inodep = NULL;
+		return err;
+	}
+	drop_nlink(inode);
+	ext4_orphan_add(handle, inode);
+	unlock_new_inode(inode);
+	return err;
+}
+
+/*
+ * By the time this is called, we already have created
+ * the directory cache entry for the new file, but it
+ * is so far negative - it has no inode.
+ *
+ * If the create succeeds, we fill in the inode information
+ * with d_instantiate().
+ */
+static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+		       bool excl)
+{
+	handle_t *handle;
+	struct inode *inode;
+	int err, credits, retries = 0;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
+retry:
+	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
+					    NULL, EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		inode->i_op = &ext4_file_inode_operations;
+		inode->i_fop = &ext4_file_operations;
+		ext4_set_aops(inode);
+		err = ext4_add_nondir(handle, dentry, &inode);
+		if (!err)
+			ext4_fc_track_create(handle, dentry);
+	}
+	if (handle)
+		ext4_journal_stop(handle);
+	if (!IS_ERR_OR_NULL(inode))
+		iput(inode);
+	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+static int ext4_mknod(struct inode *dir, struct dentry *dentry,
+		      umode_t mode, dev_t rdev)
+{
+	handle_t *handle;
+	struct inode *inode;
+	int err, credits, retries = 0;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
+retry:
+	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
+					    NULL, EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		init_special_inode(inode, inode->i_mode, rdev);
+		inode->i_op = &ext4_special_inode_operations;
+		err = ext4_add_nondir(handle, dentry, &inode);
+		if (!err)
+			ext4_fc_track_create(handle, dentry);
+	}
+	if (handle)
+		ext4_journal_stop(handle);
+	if (!IS_ERR_OR_NULL(inode))
+		iput(inode);
+	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	handle_t *handle;
+	struct inode *inode;
+	int err, retries = 0;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+retry:
+	inode = ext4_new_inode_start_handle(dir, mode,
+					    NULL, 0, NULL,
+					    EXT4_HT_DIR,
+			EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
+			  4 + EXT4_XATTR_TRANS_BLOCKS);
+	handle = ext4_journal_current_handle();
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		inode->i_op = &ext4_file_inode_operations;
+		inode->i_fop = &ext4_file_operations;
+		ext4_set_aops(inode);
+		d_tmpfile(dentry, inode);
+		err = ext4_orphan_add(handle, inode);
+		if (err)
+			goto err_unlock_inode;
+		mark_inode_dirty(inode);
+		unlock_new_inode(inode);
+	}
+	if (handle)
+		ext4_journal_stop(handle);
+	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+err_unlock_inode:
+	ext4_journal_stop(handle);
+	unlock_new_inode(inode);
+	return err;
+}
+
+struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
+			  struct ext4_dir_entry_2 *de,
+			  int blocksize, int csum_size,
+			  unsigned int parent_ino, int dotdot_real_len)
+{
+	de->inode = cpu_to_le32(inode->i_ino);
+	de->name_len = 1;
+	de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
+					   blocksize);
+	strcpy(de->name, ".");
+	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
+
+	de = ext4_next_entry(de, blocksize);
+	de->inode = cpu_to_le32(parent_ino);
+	de->name_len = 2;
+	if (!dotdot_real_len)
+		de->rec_len = ext4_rec_len_to_disk(blocksize -
+					(csum_size + EXT4_DIR_REC_LEN(1)),
+					blocksize);
+	else
+		de->rec_len = ext4_rec_len_to_disk(
+				EXT4_DIR_REC_LEN(de->name_len), blocksize);
+	strcpy(de->name, "..");
+	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
+
+	return ext4_next_entry(de, blocksize);
+}
+
+int ext4_init_new_dir(handle_t *handle, struct inode *dir,
+			     struct inode *inode)
+{
+	struct buffer_head *dir_block = NULL;
+	struct ext4_dir_entry_2 *de;
+	ext4_lblk_t block = 0;
+	unsigned int blocksize = dir->i_sb->s_blocksize;
+	int csum_size = 0;
+	int err;
+
+	if (ext4_has_metadata_csum(dir->i_sb))
+		csum_size = sizeof(struct ext4_dir_entry_tail);
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
+		err = ext4_try_create_inline_dir(handle, dir, inode);
+		if (err < 0 && err != -ENOSPC)
+			goto out;
+		if (!err)
+			goto out;
+	}
+
+	inode->i_size = 0;
+	dir_block = ext4_append(handle, inode, &block);
+	if (IS_ERR(dir_block))
+		return PTR_ERR(dir_block);
+	de = (struct ext4_dir_entry_2 *)dir_block->b_data;
+	ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
+	set_nlink(inode, 2);
+	if (csum_size)
+		ext4_initialize_dirent_tail(dir_block, blocksize);
+
+	BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
+	if (err)
+		goto out;
+	set_buffer_verified(dir_block);
+out:
+	brelse(dir_block);
+	return err;
+}
+
+static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	handle_t *handle;
+	struct inode *inode;
+	int err, err2 = 0, credits, retries = 0;
+
+	if (EXT4_DIR_LINK_MAX(dir))
+		return -EMLINK;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
+retry:
+	inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
+					    &dentry->d_name,
+					    0, NULL, EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_stop;
+
+	inode->i_op = &ext4_dir_inode_operations;
+	inode->i_fop = &ext4_dir_operations;
+	err = ext4_init_new_dir(handle, dir, inode);
+	if (err)
+		goto out_clear_inode;
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (!err)
+		err = ext4_add_entry(handle, dentry, inode);
+	if (err) {
+out_clear_inode:
+		clear_nlink(inode);
+		ext4_orphan_add(handle, inode);
+		unlock_new_inode(inode);
+		err2 = ext4_mark_inode_dirty(handle, inode);
+		if (unlikely(err2))
+			err = err2;
+		ext4_journal_stop(handle);
+		iput(inode);
+		goto out_retry;
+	}
+	ext4_inc_count(dir);
+
+	ext4_update_dx_flag(dir);
+	err = ext4_mark_inode_dirty(handle, dir);
+	if (err)
+		goto out_clear_inode;
+	d_instantiate_new(dentry, inode);
+	ext4_fc_track_create(handle, dentry);
+	if (IS_DIRSYNC(dir))
+		ext4_handle_sync(handle);
+
+out_stop:
+	if (handle)
+		ext4_journal_stop(handle);
+out_retry:
+	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+bool ext4_empty_dir(struct inode *inode)
+{
+	unsigned int offset;
+	struct buffer_head *bh;
+	struct ext4_dir_entry_2 *de;
+	struct super_block *sb;
+
+	if (ext4_has_inline_data(inode)) {
+		int has_inline_data = 1;
+		int ret;
+
+		ret = empty_inline_dir(inode, &has_inline_data);
+		if (has_inline_data)
+			return ret;
+	}
+
+	sb = inode->i_sb;
+	if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
+		EXT4_ERROR_INODE(inode, "invalid size");
+		return false;
+	}
+	/* The first directory block must not be a hole,
+	 * so treat it as DIRENT_HTREE
+	 */
+	bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
+	if (IS_ERR(bh))
+		return false;
+
+	de = (struct ext4_dir_entry_2 *) bh->b_data;
+	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
+				 0) ||
+	    le32_to_cpu(de->inode) != inode->i_ino || strcmp(".", de->name)) {
+		ext4_warning_inode(inode, "directory missing '.'");
+		brelse(bh);
+		return false;
+	}
+	offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
+	de = ext4_next_entry(de, sb->s_blocksize);
+	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
+				 offset) ||
+	    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
+		ext4_warning_inode(inode, "directory missing '..'");
+		brelse(bh);
+		return false;
+	}
+	offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
+	while (offset < inode->i_size) {
+		if (!(offset & (sb->s_blocksize - 1))) {
+			unsigned int lblock;
+			brelse(bh);
+			lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
+			bh = ext4_read_dirblock(inode, lblock, EITHER);
+			if (bh == NULL) {
+				offset += sb->s_blocksize;
+				continue;
+			}
+			if (IS_ERR(bh))
+				return false;
+		}
+		de = (struct ext4_dir_entry_2 *) (bh->b_data +
+					(offset & (sb->s_blocksize - 1)));
+		if (ext4_check_dir_entry(inode, NULL, de, bh,
+					 bh->b_data, bh->b_size, offset) ||
+		    le32_to_cpu(de->inode)) {
+			brelse(bh);
+			return false;
+		}
+		offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
+	}
+	brelse(bh);
+	return true;
+}
+
+/*
+ * ext4_orphan_add() links an unlinked or truncated inode into a list of
+ * such inodes, starting at the superblock, in case we crash before the
+ * file is closed/deleted, or in case the inode truncate spans multiple
+ * transactions and the last transaction is not recovered after a crash.
+ *
+ * At filesystem recovery time, we walk this list deleting unlinked
+ * inodes and truncating linked inodes in ext4_orphan_cleanup().
+ *
+ * Orphan list manipulation functions must be called under i_mutex unless
+ * we are just creating the inode or deleting it.
+ */
+int ext4_orphan_add(handle_t *handle, struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_iloc iloc;
+	int err = 0, rc;
+	bool dirty = false;
+
+	if (!sbi->s_journal || is_bad_inode(inode))
+		return 0;
+
+	WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
+		     !inode_is_locked(inode));
+	/*
+	 * Exit early if inode already is on orphan list. This is a big speedup
+	 * since we don't have to contend on the global s_orphan_lock.
+	 */
+	if (!list_empty(&EXT4_I(inode)->i_orphan))
+		return 0;
+
+	/*
+	 * Orphan handling is only valid for files with data blocks
+	 * being truncated, or files being unlinked. Note that we either
+	 * hold i_mutex, or the inode can not be referenced from outside,
+	 * so i_nlink should not be bumped due to race
+	 */
+	J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		  S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
+
+	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+	if (err)
+		goto out;
+
+	err = ext4_reserve_inode_write(handle, inode, &iloc);
+	if (err)
+		goto out;
+
+	mutex_lock(&sbi->s_orphan_lock);
+	/*
+	 * Due to previous errors inode may be already a part of on-disk
+	 * orphan list. If so skip on-disk list modification.
+	 */
+	if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
+	    (le32_to_cpu(sbi->s_es->s_inodes_count))) {
+		/* Insert this inode at the head of the on-disk orphan list */
+		NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
+		sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
+		dirty = true;
+	}
+	list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
+	mutex_unlock(&sbi->s_orphan_lock);
+
+	if (dirty) {
+		err = ext4_handle_dirty_super(handle, sb);
+		rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
+		if (!err)
+			err = rc;
+		if (err) {
+			/*
+			 * We have to remove inode from in-memory list if
+			 * addition to on disk orphan list failed. Stray orphan
+			 * list entries can cause panics at unmount time.
+			 */
+			mutex_lock(&sbi->s_orphan_lock);
+			list_del_init(&EXT4_I(inode)->i_orphan);
+			mutex_unlock(&sbi->s_orphan_lock);
+		}
+	} else
+		brelse(iloc.bh);
+
+	jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
+	jbd_debug(4, "orphan inode %lu will point to %d\n",
+			inode->i_ino, NEXT_ORPHAN(inode));
+out:
+	ext4_std_error(sb, err);
+	return err;
+}
+
+/*
+ * ext4_orphan_del() removes an unlinked or truncated inode from the list
+ * of such inodes stored on disk, because it is finally being cleaned up.
+ */
+int ext4_orphan_del(handle_t *handle, struct inode *inode)
+{
+	struct list_head *prev;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	__u32 ino_next;
+	struct ext4_iloc iloc;
+	int err = 0;
+
+	if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
+		return 0;
+
+	WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
+		     !inode_is_locked(inode));
+	/* Do this quick check before taking global s_orphan_lock. */
+	if (list_empty(&ei->i_orphan))
+		return 0;
+
+	if (handle) {
+		/* Grab inode buffer early before taking global s_orphan_lock */
+		err = ext4_reserve_inode_write(handle, inode, &iloc);
+	}
+
+	mutex_lock(&sbi->s_orphan_lock);
+	jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
+
+	prev = ei->i_orphan.prev;
+	list_del_init(&ei->i_orphan);
+
+	/* If we're on an error path, we may not have a valid
+	 * transaction handle with which to update the orphan list on
+	 * disk, but we still need to remove the inode from the linked
+	 * list in memory. */
+	if (!handle || err) {
+		mutex_unlock(&sbi->s_orphan_lock);
+		goto out_err;
+	}
+
+	ino_next = NEXT_ORPHAN(inode);
+	if (prev == &sbi->s_orphan) {
+		jbd_debug(4, "superblock will point to %u\n", ino_next);
+		BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+		if (err) {
+			mutex_unlock(&sbi->s_orphan_lock);
+			goto out_brelse;
+		}
+		sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
+		mutex_unlock(&sbi->s_orphan_lock);
+		err = ext4_handle_dirty_super(handle, inode->i_sb);
+	} else {
+		struct ext4_iloc iloc2;
+		struct inode *i_prev =
+			&list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
+
+		jbd_debug(4, "orphan inode %lu will point to %u\n",
+			  i_prev->i_ino, ino_next);
+		err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
+		if (err) {
+			mutex_unlock(&sbi->s_orphan_lock);
+			goto out_brelse;
+		}
+		NEXT_ORPHAN(i_prev) = ino_next;
+		err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
+		mutex_unlock(&sbi->s_orphan_lock);
+	}
+	if (err)
+		goto out_brelse;
+	NEXT_ORPHAN(inode) = 0;
+	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+out_err:
+	ext4_std_error(inode->i_sb, err);
+	return err;
+
+out_brelse:
+	brelse(iloc.bh);
+	goto out_err;
+}
+
+static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	int retval;
+	struct inode *inode;
+	struct buffer_head *bh;
+	struct ext4_dir_entry_2 *de;
+	handle_t *handle = NULL;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
+		return -EIO;
+
+	/* Initialize quotas before so that eventual writes go in
+	 * separate transaction */
+	retval = dquot_initialize(dir);
+	if (retval)
+		return retval;
+	retval = dquot_initialize(d_inode(dentry));
+	if (retval)
+		return retval;
+
+	retval = -ENOENT;
+	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+	if (!bh)
+		goto end_rmdir;
+
+	inode = d_inode(dentry);
+
+	retval = -EFSCORRUPTED;
+	if (le32_to_cpu(de->inode) != inode->i_ino)
+		goto end_rmdir;
+
+	retval = -ENOTEMPTY;
+	if (!ext4_empty_dir(inode))
+		goto end_rmdir;
+
+	handle = ext4_journal_start(dir, EXT4_HT_DIR,
+				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle)) {
+		retval = PTR_ERR(handle);
+		handle = NULL;
+		goto end_rmdir;
+	}
+
+	if (IS_DIRSYNC(dir))
+		ext4_handle_sync(handle);
+
+	retval = ext4_delete_entry(handle, dir, de, bh);
+	if (retval)
+		goto end_rmdir;
+	if (!EXT4_DIR_LINK_EMPTY(inode))
+		ext4_warning_inode(inode,
+			     "empty directory '%.*s' has too many links (%u)",
+			     dentry->d_name.len, dentry->d_name.name,
+			     inode->i_nlink);
+	inode_inc_iversion(inode);
+	clear_nlink(inode);
+	/* There's no need to set i_disksize: the fact that i_nlink is
+	 * zero will ensure that the right thing happens during any
+	 * recovery. */
+	inode->i_size = 0;
+	ext4_orphan_add(handle, inode);
+	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
+	retval = ext4_mark_inode_dirty(handle, inode);
+	if (retval)
+		goto end_rmdir;
+	ext4_dec_count(dir);
+	ext4_update_dx_flag(dir);
+	ext4_fc_track_unlink(handle, dentry);
+	retval = ext4_mark_inode_dirty(handle, dir);
+
+#ifdef CONFIG_UNICODE
+	/* VFS negative dentries are incompatible with Encoding and
+	 * Case-insensitiveness. Eventually we'll want avoid
+	 * invalidating the dentries here, alongside with returning the
+	 * negative dentries at ext4_lookup(), when it is better
+	 * supported by the VFS for the CI case.
+	 */
+	if (IS_CASEFOLDED(dir))
+		d_invalidate(dentry);
+#endif
+
+end_rmdir:
+	brelse(bh);
+	if (handle)
+		ext4_journal_stop(handle);
+	return retval;
+}
+
+int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
+		  struct inode *inode,
+		  struct dentry *dentry /* NULL during fast_commit recovery */)
+{
+	int retval = -ENOENT;
+	struct buffer_head *bh;
+	struct ext4_dir_entry_2 *de;
+	handle_t *handle;
+	int skip_remove_dentry = 0;
+
+	/*
+	 * Keep this outside the transaction; it may have to set up the
+	 * directory's encryption key, which isn't GFP_NOFS-safe.
+	 */
+	bh = ext4_find_entry(dir, d_name, &de, NULL);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+
+	if (!bh)
+		return -ENOENT;
+
+	if (le32_to_cpu(de->inode) != inode->i_ino) {
+		/*
+		 * It's okay if we find dont find dentry which matches
+		 * the inode. That's because it might have gotten
+		 * renamed to a different inode number
+		 */
+		if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+			skip_remove_dentry = 1;
+		else
+			goto out_bh;
+	}
+
+	handle = ext4_journal_start(dir, EXT4_HT_DIR,
+				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle)) {
+		retval = PTR_ERR(handle);
+		goto out_bh;
+	}
+
+	if (IS_DIRSYNC(dir))
+		ext4_handle_sync(handle);
+
+	if (!skip_remove_dentry) {
+		retval = ext4_delete_entry(handle, dir, de, bh);
+		if (retval)
+			goto out_handle;
+		dir->i_ctime = dir->i_mtime = current_time(dir);
+		ext4_update_dx_flag(dir);
+		retval = ext4_mark_inode_dirty(handle, dir);
+		if (retval)
+			goto out_handle;
+	} else {
+		retval = 0;
+	}
+	if (inode->i_nlink == 0)
+		ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
+				   d_name->len, d_name->name);
+	else
+		drop_nlink(inode);
+	if (!inode->i_nlink)
+		ext4_orphan_add(handle, inode);
+	inode->i_ctime = current_time(inode);
+	retval = ext4_mark_inode_dirty(handle, inode);
+	if (dentry && !retval)
+		ext4_fc_track_unlink(handle, dentry);
+out_handle:
+	ext4_journal_stop(handle);
+out_bh:
+	brelse(bh);
+	return retval;
+}
+
+static int ext4_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int retval;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
+		return -EIO;
+
+	trace_ext4_unlink_enter(dir, dentry);
+	/*
+	 * Initialize quotas before so that eventual writes go
+	 * in separate transaction
+	 */
+	retval = dquot_initialize(dir);
+	if (retval)
+		goto out_trace;
+	retval = dquot_initialize(d_inode(dentry));
+	if (retval)
+		goto out_trace;
+
+	retval = __ext4_unlink(dir, &dentry->d_name, d_inode(dentry), dentry);
+#ifdef CONFIG_UNICODE
+	/* VFS negative dentries are incompatible with Encoding and
+	 * Case-insensitiveness. Eventually we'll want avoid
+	 * invalidating the dentries here, alongside with returning the
+	 * negative dentries at ext4_lookup(), when it is  better
+	 * supported by the VFS for the CI case.
+	 */
+	if (IS_CASEFOLDED(dir))
+		d_invalidate(dentry);
+#endif
+
+out_trace:
+	trace_ext4_unlink_exit(dentry, retval);
+	return retval;
+}
+
+static int ext4_symlink(struct inode *dir,
+			struct dentry *dentry, const char *symname)
+{
+	handle_t *handle;
+	struct inode *inode;
+	int err, len = strlen(symname);
+	int credits;
+	struct fscrypt_str disk_link;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
+		return -EIO;
+
+	err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
+				      &disk_link);
+	if (err)
+		return err;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
+		/*
+		 * For non-fast symlinks, we just allocate inode and put it on
+		 * orphan list in the first transaction => we need bitmap,
+		 * group descriptor, sb, inode block, quota blocks, and
+		 * possibly selinux xattr blocks.
+		 */
+		credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
+			  EXT4_XATTR_TRANS_BLOCKS;
+	} else {
+		/*
+		 * Fast symlink. We have to add entry to directory
+		 * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
+		 * allocate new inode (bitmap, group descriptor, inode block,
+		 * quota blocks, sb is already counted in previous macros).
+		 */
+		credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+			  EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
+	}
+
+	inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
+					    &dentry->d_name, 0, NULL,
+					    EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
+	if (IS_ERR(inode)) {
+		if (handle)
+			ext4_journal_stop(handle);
+		return PTR_ERR(inode);
+	}
+
+	if (IS_ENCRYPTED(inode)) {
+		err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
+		if (err)
+			goto err_drop_inode;
+		inode->i_op = &ext4_encrypted_symlink_inode_operations;
+	}
+
+	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
+		if (!IS_ENCRYPTED(inode))
+			inode->i_op = &ext4_symlink_inode_operations;
+		inode_nohighmem(inode);
+		ext4_set_aops(inode);
+		/*
+		 * We cannot call page_symlink() with transaction started
+		 * because it calls into ext4_write_begin() which can wait
+		 * for transaction commit if we are running out of space
+		 * and thus we deadlock. So we have to stop transaction now
+		 * and restart it when symlink contents is written.
+		 * 
+		 * To keep fs consistent in case of crash, we have to put inode
+		 * to orphan list in the mean time.
+		 */
+		drop_nlink(inode);
+		err = ext4_orphan_add(handle, inode);
+		if (handle)
+			ext4_journal_stop(handle);
+		handle = NULL;
+		if (err)
+			goto err_drop_inode;
+		err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
+		if (err)
+			goto err_drop_inode;
+		/*
+		 * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
+		 * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
+		 */
+		handle = ext4_journal_start(dir, EXT4_HT_DIR,
+				EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+				EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
+		if (IS_ERR(handle)) {
+			err = PTR_ERR(handle);
+			handle = NULL;
+			goto err_drop_inode;
+		}
+		set_nlink(inode, 1);
+		err = ext4_orphan_del(handle, inode);
+		if (err)
+			goto err_drop_inode;
+	} else {
+		/* clear the extent format for fast symlink */
+		ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
+		if (!IS_ENCRYPTED(inode)) {
+			inode->i_op = &ext4_fast_symlink_inode_operations;
+			inode->i_link = (char *)&EXT4_I(inode)->i_data;
+		}
+		memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
+		       disk_link.len);
+		inode->i_size = disk_link.len - 1;
+	}
+	EXT4_I(inode)->i_disksize = inode->i_size;
+	err = ext4_add_nondir(handle, dentry, &inode);
+	if (handle)
+		ext4_journal_stop(handle);
+	if (inode)
+		iput(inode);
+	goto out_free_encrypted_link;
+
+err_drop_inode:
+	if (handle)
+		ext4_journal_stop(handle);
+	clear_nlink(inode);
+	unlock_new_inode(inode);
+	iput(inode);
+out_free_encrypted_link:
+	if (disk_link.name != (unsigned char *)symname)
+		kfree(disk_link.name);
+	return err;
+}
+
+int __ext4_link(struct inode *dir, struct inode *inode, struct dentry *dentry)
+{
+	handle_t *handle;
+	int err, retries = 0;
+retry:
+	handle = ext4_journal_start(dir, EXT4_HT_DIR,
+		(EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+		 EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		ext4_handle_sync(handle);
+
+	inode->i_ctime = current_time(inode);
+	ext4_inc_count(inode);
+	ihold(inode);
+
+	err = ext4_add_entry(handle, dentry, inode);
+	if (!err) {
+		err = ext4_mark_inode_dirty(handle, inode);
+		/* this can happen only for tmpfile being
+		 * linked the first time
+		 */
+		if (inode->i_nlink == 1)
+			ext4_orphan_del(handle, inode);
+		d_instantiate(dentry, inode);
+		ext4_fc_track_link(handle, dentry);
+	} else {
+		drop_nlink(inode);
+		iput(inode);
+	}
+	ext4_journal_stop(handle);
+	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+static int ext4_link(struct dentry *old_dentry,
+		     struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = d_inode(old_dentry);
+	int err;
+
+	if (inode->i_nlink >= EXT4_LINK_MAX)
+		return -EMLINK;
+
+	err = fscrypt_prepare_link(old_dentry, dir, dentry);
+	if (err)
+		return err;
+
+	if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
+	    (!projid_eq(EXT4_I(dir)->i_projid,
+			EXT4_I(old_dentry->d_inode)->i_projid)))
+		return -EXDEV;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+	return __ext4_link(dir, inode, dentry);
+}
+
+/*
+ * Try to find buffer head where contains the parent block.
+ * It should be the inode block if it is inlined or the 1st block
+ * if it is a normal dir.
+ */
+static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
+					struct inode *inode,
+					int *retval,
+					struct ext4_dir_entry_2 **parent_de,
+					int *inlined)
+{
+	struct buffer_head *bh;
+
+	if (!ext4_has_inline_data(inode)) {
+		struct ext4_dir_entry_2 *de;
+		unsigned int offset;
+
+		/* The first directory block must not be a hole, so
+		 * treat it as DIRENT_HTREE
+		 */
+		bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
+		if (IS_ERR(bh)) {
+			*retval = PTR_ERR(bh);
+			return NULL;
+		}
+
+		de = (struct ext4_dir_entry_2 *) bh->b_data;
+		if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
+					 bh->b_size, 0) ||
+		    le32_to_cpu(de->inode) != inode->i_ino ||
+		    strcmp(".", de->name)) {
+			EXT4_ERROR_INODE(inode, "directory missing '.'");
+			brelse(bh);
+			*retval = -EFSCORRUPTED;
+			return NULL;
+		}
+		offset = ext4_rec_len_from_disk(de->rec_len,
+						inode->i_sb->s_blocksize);
+		de = ext4_next_entry(de, inode->i_sb->s_blocksize);
+		if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
+					 bh->b_size, offset) ||
+		    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
+			EXT4_ERROR_INODE(inode, "directory missing '..'");
+			brelse(bh);
+			*retval = -EFSCORRUPTED;
+			return NULL;
+		}
+		*parent_de = de;
+
+		return bh;
+	}
+
+	*inlined = 1;
+	return ext4_get_first_inline_block(inode, parent_de, retval);
+}
+
+struct ext4_renament {
+	struct inode *dir;
+	struct dentry *dentry;
+	struct inode *inode;
+	bool is_dir;
+	int dir_nlink_delta;
+
+	/* entry for "dentry" */
+	struct buffer_head *bh;
+	struct ext4_dir_entry_2 *de;
+	int inlined;
+
+	/* entry for ".." in inode if it's a directory */
+	struct buffer_head *dir_bh;
+	struct ext4_dir_entry_2 *parent_de;
+	int dir_inlined;
+};
+
+static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
+{
+	int retval;
+
+	ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
+					      &retval, &ent->parent_de,
+					      &ent->dir_inlined);
+	if (!ent->dir_bh)
+		return retval;
+	if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
+		return -EFSCORRUPTED;
+	BUFFER_TRACE(ent->dir_bh, "get_write_access");
+	return ext4_journal_get_write_access(handle, ent->dir_bh);
+}
+
+static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
+				  unsigned dir_ino)
+{
+	int retval;
+
+	ent->parent_de->inode = cpu_to_le32(dir_ino);
+	BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
+	if (!ent->dir_inlined) {
+		if (is_dx(ent->inode)) {
+			retval = ext4_handle_dirty_dx_node(handle,
+							   ent->inode,
+							   ent->dir_bh);
+		} else {
+			retval = ext4_handle_dirty_dirblock(handle, ent->inode,
+							    ent->dir_bh);
+		}
+	} else {
+		retval = ext4_mark_inode_dirty(handle, ent->inode);
+	}
+	if (retval) {
+		ext4_std_error(ent->dir->i_sb, retval);
+		return retval;
+	}
+	return 0;
+}
+
+static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
+		       unsigned ino, unsigned file_type)
+{
+	int retval, retval2;
+
+	BUFFER_TRACE(ent->bh, "get write access");
+	retval = ext4_journal_get_write_access(handle, ent->bh);
+	if (retval)
+		return retval;
+	ent->de->inode = cpu_to_le32(ino);
+	if (ext4_has_feature_filetype(ent->dir->i_sb))
+		ent->de->file_type = file_type;
+	inode_inc_iversion(ent->dir);
+	ent->dir->i_ctime = ent->dir->i_mtime =
+		current_time(ent->dir);
+	retval = ext4_mark_inode_dirty(handle, ent->dir);
+	BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
+	if (!ent->inlined) {
+		retval2 = ext4_handle_dirty_dirblock(handle, ent->dir, ent->bh);
+		if (unlikely(retval2)) {
+			ext4_std_error(ent->dir->i_sb, retval2);
+			return retval2;
+		}
+	}
+	return retval;
+}
+
+static void ext4_resetent(handle_t *handle, struct ext4_renament *ent,
+			  unsigned ino, unsigned file_type)
+{
+	struct ext4_renament old = *ent;
+	int retval = 0;
+
+	/*
+	 * old->de could have moved from under us during make indexed dir,
+	 * so the old->de may no longer valid and need to find it again
+	 * before reset old inode info.
+	 */
+	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de,
+				 &old.inlined);
+	if (IS_ERR(old.bh))
+		retval = PTR_ERR(old.bh);
+	if (!old.bh)
+		retval = -ENOENT;
+	if (retval) {
+		ext4_std_error(old.dir->i_sb, retval);
+		return;
+	}
+
+	ext4_setent(handle, &old, ino, file_type);
+	brelse(old.bh);
+}
+
+static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
+				  const struct qstr *d_name)
+{
+	int retval = -ENOENT;
+	struct buffer_head *bh;
+	struct ext4_dir_entry_2 *de;
+
+	bh = ext4_find_entry(dir, d_name, &de, NULL);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+	if (bh) {
+		retval = ext4_delete_entry(handle, dir, de, bh);
+		brelse(bh);
+	}
+	return retval;
+}
+
+static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
+			       int force_reread)
+{
+	int retval;
+	/*
+	 * ent->de could have moved from under us during htree split, so make
+	 * sure that we are deleting the right entry.  We might also be pointing
+	 * to a stale entry in the unused part of ent->bh so just checking inum
+	 * and the name isn't enough.
+	 */
+	if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
+	    ent->de->name_len != ent->dentry->d_name.len ||
+	    strncmp(ent->de->name, ent->dentry->d_name.name,
+		    ent->de->name_len) ||
+	    force_reread) {
+		retval = ext4_find_delete_entry(handle, ent->dir,
+						&ent->dentry->d_name);
+	} else {
+		retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
+		if (retval == -ENOENT) {
+			retval = ext4_find_delete_entry(handle, ent->dir,
+							&ent->dentry->d_name);
+		}
+	}
+
+	if (retval) {
+		ext4_warning_inode(ent->dir,
+				   "Deleting old file: nlink %d, error=%d",
+				   ent->dir->i_nlink, retval);
+	}
+}
+
+static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
+{
+	if (ent->dir_nlink_delta) {
+		if (ent->dir_nlink_delta == -1)
+			ext4_dec_count(ent->dir);
+		else
+			ext4_inc_count(ent->dir);
+		ext4_mark_inode_dirty(handle, ent->dir);
+	}
+}
+
+static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
+					      int credits, handle_t **h)
+{
+	struct inode *wh;
+	handle_t *handle;
+	int retries = 0;
+
+	/*
+	 * for inode block, sb block, group summaries,
+	 * and inode bitmap
+	 */
+	credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
+		    EXT4_XATTR_TRANS_BLOCKS + 4);
+retry:
+	wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
+					 &ent->dentry->d_name, 0, NULL,
+					 EXT4_HT_DIR, credits);
+
+	handle = ext4_journal_current_handle();
+	if (IS_ERR(wh)) {
+		if (handle)
+			ext4_journal_stop(handle);
+		if (PTR_ERR(wh) == -ENOSPC &&
+		    ext4_should_retry_alloc(ent->dir->i_sb, &retries))
+			goto retry;
+	} else {
+		*h = handle;
+		init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
+		wh->i_op = &ext4_special_inode_operations;
+	}
+	return wh;
+}
+
+/*
+ * Anybody can rename anything with this: the permission checks are left to the
+ * higher-level routines.
+ *
+ * n.b.  old_{dentry,inode) refers to the source dentry/inode
+ * while new_{dentry,inode) refers to the destination dentry/inode
+ * This comes from rename(const char *oldpath, const char *newpath)
+ */
+static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
+		       struct inode *new_dir, struct dentry *new_dentry,
+		       unsigned int flags)
+{
+	handle_t *handle = NULL;
+	struct ext4_renament old = {
+		.dir = old_dir,
+		.dentry = old_dentry,
+		.inode = d_inode(old_dentry),
+	};
+	struct ext4_renament new = {
+		.dir = new_dir,
+		.dentry = new_dentry,
+		.inode = d_inode(new_dentry),
+	};
+	int force_reread;
+	int retval;
+	struct inode *whiteout = NULL;
+	int credits;
+	u8 old_file_type;
+
+	if (new.inode && new.inode->i_nlink == 0) {
+		EXT4_ERROR_INODE(new.inode,
+				 "target of rename is already freed");
+		return -EFSCORRUPTED;
+	}
+
+	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
+	    (!projid_eq(EXT4_I(new_dir)->i_projid,
+			EXT4_I(old_dentry->d_inode)->i_projid)))
+		return -EXDEV;
+
+	retval = dquot_initialize(old.dir);
+	if (retval)
+		return retval;
+	retval = dquot_initialize(old.inode);
+	if (retval)
+		return retval;
+	retval = dquot_initialize(new.dir);
+	if (retval)
+		return retval;
+
+	/* Initialize quotas before so that eventual writes go
+	 * in separate transaction */
+	if (new.inode) {
+		retval = dquot_initialize(new.inode);
+		if (retval)
+			return retval;
+	}
+
+	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de,
+				 &old.inlined);
+	if (IS_ERR(old.bh))
+		return PTR_ERR(old.bh);
+
+	/*
+	 *  Check for inode number is _not_ due to possible IO errors.
+	 *  We might rmdir the source, keep it as pwd of some process
+	 *  and merrily kill the link to whatever was created under the
+	 *  same name. Goodbye sticky bit ;-<
+	 */
+	retval = -ENOENT;
+	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
+		goto release_bh;
+
+	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
+				 &new.de, &new.inlined);
+	if (IS_ERR(new.bh)) {
+		retval = PTR_ERR(new.bh);
+		new.bh = NULL;
+		goto release_bh;
+	}
+	if (new.bh) {
+		if (!new.inode) {
+			brelse(new.bh);
+			new.bh = NULL;
+		}
+	}
+	if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
+		ext4_alloc_da_blocks(old.inode);
+
+	credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
+		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
+	if (!(flags & RENAME_WHITEOUT)) {
+		handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
+		if (IS_ERR(handle)) {
+			retval = PTR_ERR(handle);
+			goto release_bh;
+		}
+	} else {
+		whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
+		if (IS_ERR(whiteout)) {
+			retval = PTR_ERR(whiteout);
+			goto release_bh;
+		}
+	}
+
+	old_file_type = old.de->file_type;
+	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
+		ext4_handle_sync(handle);
+
+	if (S_ISDIR(old.inode->i_mode)) {
+		if (new.inode) {
+			retval = -ENOTEMPTY;
+			if (!ext4_empty_dir(new.inode))
+				goto end_rename;
+		} else {
+			retval = -EMLINK;
+			if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
+				goto end_rename;
+		}
+		retval = ext4_rename_dir_prepare(handle, &old);
+		if (retval)
+			goto end_rename;
+	}
+	/*
+	 * If we're renaming a file within an inline_data dir and adding or
+	 * setting the new dirent causes a conversion from inline_data to
+	 * extents/blockmap, we need to force the dirent delete code to
+	 * re-read the directory, or else we end up trying to delete a dirent
+	 * from what is now the extent tree root (or a block map).
+	 */
+	force_reread = (new.dir->i_ino == old.dir->i_ino &&
+			ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
+
+	if (whiteout) {
+		/*
+		 * Do this before adding a new entry, so the old entry is sure
+		 * to be still pointing to the valid old entry.
+		 */
+		retval = ext4_setent(handle, &old, whiteout->i_ino,
+				     EXT4_FT_CHRDEV);
+		if (retval)
+			goto end_rename;
+		retval = ext4_mark_inode_dirty(handle, whiteout);
+		if (unlikely(retval))
+			goto end_rename;
+
+	}
+	if (!new.bh) {
+		retval = ext4_add_entry(handle, new.dentry, old.inode);
+		if (retval)
+			goto end_rename;
+	} else {
+		retval = ext4_setent(handle, &new,
+				     old.inode->i_ino, old_file_type);
+		if (retval)
+			goto end_rename;
+	}
+	if (force_reread)
+		force_reread = !ext4_test_inode_flag(new.dir,
+						     EXT4_INODE_INLINE_DATA);
+
+	/*
+	 * Like most other Unix systems, set the ctime for inodes on a
+	 * rename.
+	 */
+	old.inode->i_ctime = current_time(old.inode);
+	retval = ext4_mark_inode_dirty(handle, old.inode);
+	if (unlikely(retval))
+		goto end_rename;
+
+	if (!whiteout) {
+		/*
+		 * ok, that's it
+		 */
+		ext4_rename_delete(handle, &old, force_reread);
+	}
+
+	if (new.inode) {
+		ext4_dec_count(new.inode);
+		new.inode->i_ctime = current_time(new.inode);
+	}
+	old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
+	ext4_update_dx_flag(old.dir);
+	if (old.dir_bh) {
+		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
+		if (retval)
+			goto end_rename;
+
+		ext4_dec_count(old.dir);
+		if (new.inode) {
+			/* checked ext4_empty_dir above, can't have another
+			 * parent, ext4_dec_count() won't work for many-linked
+			 * dirs */
+			clear_nlink(new.inode);
+		} else {
+			ext4_inc_count(new.dir);
+			ext4_update_dx_flag(new.dir);
+			retval = ext4_mark_inode_dirty(handle, new.dir);
+			if (unlikely(retval))
+				goto end_rename;
+		}
+	}
+	retval = ext4_mark_inode_dirty(handle, old.dir);
+	if (unlikely(retval))
+		goto end_rename;
+
+	if (S_ISDIR(old.inode->i_mode)) {
+		/*
+		 * We disable fast commits here that's because the
+		 * replay code is not yet capable of changing dot dot
+		 * dirents in directories.
+		 */
+		ext4_fc_mark_ineligible(old.inode->i_sb,
+			EXT4_FC_REASON_RENAME_DIR);
+	} else {
+		if (new.inode)
+			ext4_fc_track_unlink(handle, new.dentry);
+		__ext4_fc_track_link(handle, old.inode, new.dentry);
+		__ext4_fc_track_unlink(handle, old.inode, old.dentry);
+		if (whiteout)
+			__ext4_fc_track_create(handle, whiteout, old.dentry);
+	}
+
+	if (new.inode) {
+		retval = ext4_mark_inode_dirty(handle, new.inode);
+		if (unlikely(retval))
+			goto end_rename;
+		if (!new.inode->i_nlink)
+			ext4_orphan_add(handle, new.inode);
+	}
+	retval = 0;
+
+end_rename:
+	if (whiteout) {
+		if (retval) {
+			ext4_resetent(handle, &old,
+				      old.inode->i_ino, old_file_type);
+			drop_nlink(whiteout);
+			ext4_orphan_add(handle, whiteout);
+		}
+		unlock_new_inode(whiteout);
+		ext4_journal_stop(handle);
+		iput(whiteout);
+	} else {
+		ext4_journal_stop(handle);
+	}
+release_bh:
+	brelse(old.dir_bh);
+	brelse(old.bh);
+	brelse(new.bh);
+
+	return retval;
+}
+
+static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
+			     struct inode *new_dir, struct dentry *new_dentry)
+{
+	handle_t *handle = NULL;
+	struct ext4_renament old = {
+		.dir = old_dir,
+		.dentry = old_dentry,
+		.inode = d_inode(old_dentry),
+	};
+	struct ext4_renament new = {
+		.dir = new_dir,
+		.dentry = new_dentry,
+		.inode = d_inode(new_dentry),
+	};
+	u8 new_file_type;
+	int retval;
+	struct timespec64 ctime;
+
+	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
+	     !projid_eq(EXT4_I(new_dir)->i_projid,
+			EXT4_I(old_dentry->d_inode)->i_projid)) ||
+	    (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
+	     !projid_eq(EXT4_I(old_dir)->i_projid,
+			EXT4_I(new_dentry->d_inode)->i_projid)))
+		return -EXDEV;
+
+	retval = dquot_initialize(old.dir);
+	if (retval)
+		return retval;
+	retval = dquot_initialize(new.dir);
+	if (retval)
+		return retval;
+
+	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
+				 &old.de, &old.inlined);
+	if (IS_ERR(old.bh))
+		return PTR_ERR(old.bh);
+	/*
+	 *  Check for inode number is _not_ due to possible IO errors.
+	 *  We might rmdir the source, keep it as pwd of some process
+	 *  and merrily kill the link to whatever was created under the
+	 *  same name. Goodbye sticky bit ;-<
+	 */
+	retval = -ENOENT;
+	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
+		goto end_rename;
+
+	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
+				 &new.de, &new.inlined);
+	if (IS_ERR(new.bh)) {
+		retval = PTR_ERR(new.bh);
+		new.bh = NULL;
+		goto end_rename;
+	}
+
+	/* RENAME_EXCHANGE case: old *and* new must both exist */
+	if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
+		goto end_rename;
+
+	handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
+		(2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
+		 2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
+	if (IS_ERR(handle)) {
+		retval = PTR_ERR(handle);
+		handle = NULL;
+		goto end_rename;
+	}
+
+	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
+		ext4_handle_sync(handle);
+
+	if (S_ISDIR(old.inode->i_mode)) {
+		old.is_dir = true;
+		retval = ext4_rename_dir_prepare(handle, &old);
+		if (retval)
+			goto end_rename;
+	}
+	if (S_ISDIR(new.inode->i_mode)) {
+		new.is_dir = true;
+		retval = ext4_rename_dir_prepare(handle, &new);
+		if (retval)
+			goto end_rename;
+	}
+
+	/*
+	 * Other than the special case of overwriting a directory, parents'
+	 * nlink only needs to be modified if this is a cross directory rename.
+	 */
+	if (old.dir != new.dir && old.is_dir != new.is_dir) {
+		old.dir_nlink_delta = old.is_dir ? -1 : 1;
+		new.dir_nlink_delta = -old.dir_nlink_delta;
+		retval = -EMLINK;
+		if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
+		    (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
+			goto end_rename;
+	}
+
+	new_file_type = new.de->file_type;
+	retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
+	if (retval)
+		goto end_rename;
+
+	retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
+	if (retval)
+		goto end_rename;
+
+	/*
+	 * Like most other Unix systems, set the ctime for inodes on a
+	 * rename.
+	 */
+	ctime = current_time(old.inode);
+	old.inode->i_ctime = ctime;
+	new.inode->i_ctime = ctime;
+	retval = ext4_mark_inode_dirty(handle, old.inode);
+	if (unlikely(retval))
+		goto end_rename;
+	retval = ext4_mark_inode_dirty(handle, new.inode);
+	if (unlikely(retval))
+		goto end_rename;
+	ext4_fc_mark_ineligible(new.inode->i_sb,
+				EXT4_FC_REASON_CROSS_RENAME);
+	if (old.dir_bh) {
+		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
+		if (retval)
+			goto end_rename;
+	}
+	if (new.dir_bh) {
+		retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
+		if (retval)
+			goto end_rename;
+	}
+	ext4_update_dir_count(handle, &old);
+	ext4_update_dir_count(handle, &new);
+	retval = 0;
+
+end_rename:
+	brelse(old.dir_bh);
+	brelse(new.dir_bh);
+	brelse(old.bh);
+	brelse(new.bh);
+	if (handle)
+		ext4_journal_stop(handle);
+	return retval;
+}
+
+static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
+			struct inode *new_dir, struct dentry *new_dentry,
+			unsigned int flags)
+{
+	int err;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
+		return -EIO;
+
+	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
+		return -EINVAL;
+
+	err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
+				     flags);
+	if (err)
+		return err;
+
+	if (flags & RENAME_EXCHANGE) {
+		return ext4_cross_rename(old_dir, old_dentry,
+					 new_dir, new_dentry);
+	}
+
+	return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
+}
+
+/*
+ * directories can handle most operations...
+ */
+const struct inode_operations ext4_dir_inode_operations = {
+	.create		= ext4_create,
+	.lookup		= ext4_lookup,
+	.link		= ext4_link,
+	.unlink		= ext4_unlink,
+	.symlink	= ext4_symlink,
+	.mkdir		= ext4_mkdir,
+	.rmdir		= ext4_rmdir,
+	.mknod		= ext4_mknod,
+	.tmpfile	= ext4_tmpfile,
+	.rename		= ext4_rename2,
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_getattr,
+	.listxattr	= ext4_listxattr,
+	.get_acl	= ext4_get_acl,
+	.set_acl	= ext4_set_acl,
+	.fiemap         = ext4_fiemap,
+};
+
+const struct inode_operations ext4_special_inode_operations = {
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_getattr,
+	.listxattr	= ext4_listxattr,
+	.get_acl	= ext4_get_acl,
+	.set_acl	= ext4_set_acl,
+};
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
new file mode 100644
index 000000000..a94cc7b22
--- /dev/null
+++ b/fs/ext4/page-io.c
@@ -0,0 +1,567 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/page-io.c
+ *
+ * This contains the new page_io functions for ext4
+ *
+ * Written by Theodore Ts'o, 2010.
+ */
+
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include <linux/mpage.h>
+#include <linux/namei.h>
+#include <linux/uio.h>
+#include <linux/bio.h>
+#include <linux/workqueue.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/backing-dev.h>
+
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+
+static struct kmem_cache *io_end_cachep;
+static struct kmem_cache *io_end_vec_cachep;
+
+int __init ext4_init_pageio(void)
+{
+	io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
+	if (io_end_cachep == NULL)
+		return -ENOMEM;
+
+	io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0);
+	if (io_end_vec_cachep == NULL) {
+		kmem_cache_destroy(io_end_cachep);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void ext4_exit_pageio(void)
+{
+	kmem_cache_destroy(io_end_cachep);
+	kmem_cache_destroy(io_end_vec_cachep);
+}
+
+struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end)
+{
+	struct ext4_io_end_vec *io_end_vec;
+
+	io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS);
+	if (!io_end_vec)
+		return ERR_PTR(-ENOMEM);
+	INIT_LIST_HEAD(&io_end_vec->list);
+	list_add_tail(&io_end_vec->list, &io_end->list_vec);
+	return io_end_vec;
+}
+
+static void ext4_free_io_end_vec(ext4_io_end_t *io_end)
+{
+	struct ext4_io_end_vec *io_end_vec, *tmp;
+
+	if (list_empty(&io_end->list_vec))
+		return;
+	list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) {
+		list_del(&io_end_vec->list);
+		kmem_cache_free(io_end_vec_cachep, io_end_vec);
+	}
+}
+
+struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end)
+{
+	BUG_ON(list_empty(&io_end->list_vec));
+	return list_last_entry(&io_end->list_vec, struct ext4_io_end_vec, list);
+}
+
+/*
+ * Print an buffer I/O error compatible with the fs/buffer.c.  This
+ * provides compatibility with dmesg scrapers that look for a specific
+ * buffer I/O error message.  We really need a unified error reporting
+ * structure to userspace ala Digital Unix's uerf system, but it's
+ * probably not going to happen in my lifetime, due to LKML politics...
+ */
+static void buffer_io_error(struct buffer_head *bh)
+{
+	printk_ratelimited(KERN_ERR "Buffer I/O error on device %pg, logical block %llu\n",
+		       bh->b_bdev,
+			(unsigned long long)bh->b_blocknr);
+}
+
+static void ext4_finish_bio(struct bio *bio)
+{
+	struct bio_vec *bvec;
+	struct bvec_iter_all iter_all;
+
+	bio_for_each_segment_all(bvec, bio, iter_all) {
+		struct page *page = bvec->bv_page;
+		struct page *bounce_page = NULL;
+		struct buffer_head *bh, *head;
+		unsigned bio_start = bvec->bv_offset;
+		unsigned bio_end = bio_start + bvec->bv_len;
+		unsigned under_io = 0;
+		unsigned long flags;
+
+		if (!page)
+			continue;
+
+		if (fscrypt_is_bounce_page(page)) {
+			bounce_page = page;
+			page = fscrypt_pagecache_page(bounce_page);
+		}
+
+		if (bio->bi_status) {
+			SetPageError(page);
+			mapping_set_error(page->mapping, -EIO);
+		}
+		bh = head = page_buffers(page);
+		/*
+		 * We check all buffers in the page under b_uptodate_lock
+		 * to avoid races with other end io clearing async_write flags
+		 */
+		spin_lock_irqsave(&head->b_uptodate_lock, flags);
+		do {
+			if (bh_offset(bh) < bio_start ||
+			    bh_offset(bh) + bh->b_size > bio_end) {
+				if (buffer_async_write(bh))
+					under_io++;
+				continue;
+			}
+			clear_buffer_async_write(bh);
+			if (bio->bi_status) {
+				set_buffer_write_io_error(bh);
+				buffer_io_error(bh);
+			}
+		} while ((bh = bh->b_this_page) != head);
+		spin_unlock_irqrestore(&head->b_uptodate_lock, flags);
+		if (!under_io) {
+			fscrypt_free_bounce_page(bounce_page);
+			end_page_writeback(page);
+		}
+	}
+}
+
+static void ext4_release_io_end(ext4_io_end_t *io_end)
+{
+	struct bio *bio, *next_bio;
+
+	BUG_ON(!list_empty(&io_end->list));
+	BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
+	WARN_ON(io_end->handle);
+
+	for (bio = io_end->bio; bio; bio = next_bio) {
+		next_bio = bio->bi_private;
+		ext4_finish_bio(bio);
+		bio_put(bio);
+	}
+	ext4_free_io_end_vec(io_end);
+	kmem_cache_free(io_end_cachep, io_end);
+}
+
+/*
+ * Check a range of space and convert unwritten extents to written. Note that
+ * we are protected from truncate touching same part of extent tree by the
+ * fact that truncate code waits for all DIO to finish (thus exclusion from
+ * direct IO is achieved) and also waits for PageWriteback bits. Thus we
+ * cannot get to ext4_ext_truncate() before all IOs overlapping that range are
+ * completed (happens from ext4_free_ioend()).
+ */
+static int ext4_end_io_end(ext4_io_end_t *io_end)
+{
+	struct inode *inode = io_end->inode;
+	handle_t *handle = io_end->handle;
+	int ret = 0;
+
+	ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p,"
+		   "list->prev 0x%p\n",
+		   io_end, inode->i_ino, io_end->list.next, io_end->list.prev);
+
+	io_end->handle = NULL;	/* Following call will use up the handle */
+	ret = ext4_convert_unwritten_io_end_vec(handle, io_end);
+	if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) {
+		ext4_msg(inode->i_sb, KERN_EMERG,
+			 "failed to convert unwritten extents to written "
+			 "extents -- potential data loss!  "
+			 "(inode %lu, error %d)", inode->i_ino, ret);
+	}
+	ext4_clear_io_unwritten_flag(io_end);
+	ext4_release_io_end(io_end);
+	return ret;
+}
+
+static void dump_completed_IO(struct inode *inode, struct list_head *head)
+{
+#ifdef	EXT4FS_DEBUG
+	struct list_head *cur, *before, *after;
+	ext4_io_end_t *io_end, *io_end0, *io_end1;
+
+	if (list_empty(head))
+		return;
+
+	ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
+	list_for_each_entry(io_end, head, list) {
+		cur = &io_end->list;
+		before = cur->prev;
+		io_end0 = container_of(before, ext4_io_end_t, list);
+		after = cur->next;
+		io_end1 = container_of(after, ext4_io_end_t, list);
+
+		ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
+			    io_end, inode->i_ino, io_end0, io_end1);
+	}
+#endif
+}
+
+/* Add the io_end to per-inode completed end_io list. */
+static void ext4_add_complete_io(ext4_io_end_t *io_end)
+{
+	struct ext4_inode_info *ei = EXT4_I(io_end->inode);
+	struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
+	struct workqueue_struct *wq;
+	unsigned long flags;
+
+	/* Only reserved conversions from writeback should enter here */
+	WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
+	WARN_ON(!io_end->handle && sbi->s_journal);
+	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+	wq = sbi->rsv_conversion_wq;
+	if (list_empty(&ei->i_rsv_conversion_list))
+		queue_work(wq, &ei->i_rsv_conversion_work);
+	list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
+	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+}
+
+static int ext4_do_flush_completed_IO(struct inode *inode,
+				      struct list_head *head)
+{
+	ext4_io_end_t *io_end;
+	struct list_head unwritten;
+	unsigned long flags;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	int err, ret = 0;
+
+	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+	dump_completed_IO(inode, head);
+	list_replace_init(head, &unwritten);
+	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+
+	while (!list_empty(&unwritten)) {
+		io_end = list_entry(unwritten.next, ext4_io_end_t, list);
+		BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
+		list_del_init(&io_end->list);
+
+		err = ext4_end_io_end(io_end);
+		if (unlikely(!ret && err))
+			ret = err;
+	}
+	return ret;
+}
+
+/*
+ * work on completed IO, to convert unwritten extents to extents
+ */
+void ext4_end_io_rsv_work(struct work_struct *work)
+{
+	struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
+						  i_rsv_conversion_work);
+	ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
+}
+
+ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
+{
+	ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags);
+
+	if (io_end) {
+		io_end->inode = inode;
+		INIT_LIST_HEAD(&io_end->list);
+		INIT_LIST_HEAD(&io_end->list_vec);
+		atomic_set(&io_end->count, 1);
+	}
+	return io_end;
+}
+
+void ext4_put_io_end_defer(ext4_io_end_t *io_end)
+{
+	if (atomic_dec_and_test(&io_end->count)) {
+		if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) ||
+				list_empty(&io_end->list_vec)) {
+			ext4_release_io_end(io_end);
+			return;
+		}
+		ext4_add_complete_io(io_end);
+	}
+}
+
+int ext4_put_io_end(ext4_io_end_t *io_end)
+{
+	int err = 0;
+
+	if (atomic_dec_and_test(&io_end->count)) {
+		if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+			err = ext4_convert_unwritten_io_end_vec(io_end->handle,
+								io_end);
+			io_end->handle = NULL;
+			ext4_clear_io_unwritten_flag(io_end);
+		}
+		ext4_release_io_end(io_end);
+	}
+	return err;
+}
+
+ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
+{
+	atomic_inc(&io_end->count);
+	return io_end;
+}
+
+/* BIO completion function for page writeback */
+static void ext4_end_bio(struct bio *bio)
+{
+	ext4_io_end_t *io_end = bio->bi_private;
+	sector_t bi_sector = bio->bi_iter.bi_sector;
+	char b[BDEVNAME_SIZE];
+
+	if (WARN_ONCE(!io_end, "io_end is NULL: %s: sector %Lu len %u err %d\n",
+		      bio_devname(bio, b),
+		      (long long) bio->bi_iter.bi_sector,
+		      (unsigned) bio_sectors(bio),
+		      bio->bi_status)) {
+		ext4_finish_bio(bio);
+		bio_put(bio);
+		return;
+	}
+	bio->bi_end_io = NULL;
+
+	if (bio->bi_status) {
+		struct inode *inode = io_end->inode;
+
+		ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
+			     "starting block %llu)",
+			     bio->bi_status, inode->i_ino,
+			     (unsigned long long)
+			     bi_sector >> (inode->i_blkbits - 9));
+		mapping_set_error(inode->i_mapping,
+				blk_status_to_errno(bio->bi_status));
+	}
+
+	if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+		/*
+		 * Link bio into list hanging from io_end. We have to do it
+		 * atomically as bio completions can be racing against each
+		 * other.
+		 */
+		bio->bi_private = xchg(&io_end->bio, bio);
+		ext4_put_io_end_defer(io_end);
+	} else {
+		/*
+		 * Drop io_end reference early. Inode can get freed once
+		 * we finish the bio.
+		 */
+		ext4_put_io_end_defer(io_end);
+		ext4_finish_bio(bio);
+		bio_put(bio);
+	}
+}
+
+void ext4_io_submit(struct ext4_io_submit *io)
+{
+	struct bio *bio = io->io_bio;
+
+	if (bio) {
+		int io_op_flags = io->io_wbc->sync_mode == WB_SYNC_ALL ?
+				  REQ_SYNC : 0;
+		io->io_bio->bi_write_hint = io->io_end->inode->i_write_hint;
+		bio_set_op_attrs(io->io_bio, REQ_OP_WRITE, io_op_flags);
+		submit_bio(io->io_bio);
+	}
+	io->io_bio = NULL;
+}
+
+void ext4_io_submit_init(struct ext4_io_submit *io,
+			 struct writeback_control *wbc)
+{
+	io->io_wbc = wbc;
+	io->io_bio = NULL;
+	io->io_end = NULL;
+}
+
+static void io_submit_init_bio(struct ext4_io_submit *io,
+			       struct buffer_head *bh)
+{
+	struct bio *bio;
+
+	/*
+	 * bio_alloc will _always_ be able to allocate a bio if
+	 * __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset().
+	 */
+	bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
+	fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
+	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+	bio_set_dev(bio, bh->b_bdev);
+	bio->bi_end_io = ext4_end_bio;
+	bio->bi_private = ext4_get_io_end(io->io_end);
+	io->io_bio = bio;
+	io->io_next_block = bh->b_blocknr;
+	wbc_init_bio(io->io_wbc, bio);
+}
+
+static void io_submit_add_bh(struct ext4_io_submit *io,
+			     struct inode *inode,
+			     struct page *pagecache_page,
+			     struct page *bounce_page,
+			     struct buffer_head *bh)
+{
+	int ret;
+
+	if (io->io_bio && (bh->b_blocknr != io->io_next_block ||
+			   !fscrypt_mergeable_bio_bh(io->io_bio, bh))) {
+submit_and_retry:
+		ext4_io_submit(io);
+	}
+	if (io->io_bio == NULL) {
+		io_submit_init_bio(io, bh);
+		io->io_bio->bi_write_hint = inode->i_write_hint;
+	}
+	ret = bio_add_page(io->io_bio, bounce_page ?: pagecache_page,
+			   bh->b_size, bh_offset(bh));
+	if (ret != bh->b_size)
+		goto submit_and_retry;
+	wbc_account_cgroup_owner(io->io_wbc, pagecache_page, bh->b_size);
+	io->io_next_block++;
+}
+
+int ext4_bio_write_page(struct ext4_io_submit *io,
+			struct page *page,
+			int len,
+			struct writeback_control *wbc,
+			bool keep_towrite)
+{
+	struct page *bounce_page = NULL;
+	struct inode *inode = page->mapping->host;
+	unsigned block_start;
+	struct buffer_head *bh, *head;
+	int ret = 0;
+	int nr_submitted = 0;
+	int nr_to_submit = 0;
+
+	BUG_ON(!PageLocked(page));
+	BUG_ON(PageWriteback(page));
+
+	if (keep_towrite)
+		set_page_writeback_keepwrite(page);
+	else
+		set_page_writeback(page);
+	ClearPageError(page);
+
+	/*
+	 * Comments copied from block_write_full_page:
+	 *
+	 * The page straddles i_size.  It must be zeroed out on each and every
+	 * writepage invocation because it may be mmapped.  "A file is mapped
+	 * in multiples of the page size.  For a file that is not a multiple of
+	 * the page size, the remaining memory is zeroed when mapped, and
+	 * writes to that region are not written out to the file."
+	 */
+	if (len < PAGE_SIZE)
+		zero_user_segment(page, len, PAGE_SIZE);
+	/*
+	 * In the first loop we prepare and mark buffers to submit. We have to
+	 * mark all buffers in the page before submitting so that
+	 * end_page_writeback() cannot be called from ext4_bio_end_io() when IO
+	 * on the first buffer finishes and we are still working on submitting
+	 * the second buffer.
+	 */
+	bh = head = page_buffers(page);
+	do {
+		block_start = bh_offset(bh);
+		if (block_start >= len) {
+			clear_buffer_dirty(bh);
+			set_buffer_uptodate(bh);
+			continue;
+		}
+		if (!buffer_dirty(bh) || buffer_delay(bh) ||
+		    !buffer_mapped(bh) || buffer_unwritten(bh)) {
+			/* A hole? We can safely clear the dirty bit */
+			if (!buffer_mapped(bh))
+				clear_buffer_dirty(bh);
+			if (io->io_bio)
+				ext4_io_submit(io);
+			continue;
+		}
+		if (buffer_new(bh))
+			clear_buffer_new(bh);
+		set_buffer_async_write(bh);
+		nr_to_submit++;
+	} while ((bh = bh->b_this_page) != head);
+
+	bh = head = page_buffers(page);
+
+	/*
+	 * If any blocks are being written to an encrypted file, encrypt them
+	 * into a bounce page.  For simplicity, just encrypt until the last
+	 * block which might be needed.  This may cause some unneeded blocks
+	 * (e.g. holes) to be unnecessarily encrypted, but this is rare and
+	 * can't happen in the common case of blocksize == PAGE_SIZE.
+	 */
+	if (fscrypt_inode_uses_fs_layer_crypto(inode) && nr_to_submit) {
+		gfp_t gfp_flags = GFP_NOFS;
+		unsigned int enc_bytes = round_up(len, i_blocksize(inode));
+
+		/*
+		 * Since bounce page allocation uses a mempool, we can only use
+		 * a waiting mask (i.e. request guaranteed allocation) on the
+		 * first page of the bio.  Otherwise it can deadlock.
+		 */
+		if (io->io_bio)
+			gfp_flags = GFP_NOWAIT | __GFP_NOWARN;
+	retry_encrypt:
+		bounce_page = fscrypt_encrypt_pagecache_blocks(page, enc_bytes,
+							       0, gfp_flags);
+		if (IS_ERR(bounce_page)) {
+			ret = PTR_ERR(bounce_page);
+			if (ret == -ENOMEM &&
+			    (io->io_bio || wbc->sync_mode == WB_SYNC_ALL)) {
+				gfp_flags = GFP_NOFS;
+				if (io->io_bio)
+					ext4_io_submit(io);
+				else
+					gfp_flags |= __GFP_NOFAIL;
+				congestion_wait(BLK_RW_ASYNC, HZ/50);
+				goto retry_encrypt;
+			}
+
+			printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
+			redirty_page_for_writepage(wbc, page);
+			do {
+				clear_buffer_async_write(bh);
+				bh = bh->b_this_page;
+			} while (bh != head);
+			goto unlock;
+		}
+	}
+
+	/* Now submit buffers to write */
+	do {
+		if (!buffer_async_write(bh))
+			continue;
+		io_submit_add_bh(io, inode, page, bounce_page, bh);
+		nr_submitted++;
+		clear_buffer_dirty(bh);
+	} while ((bh = bh->b_this_page) != head);
+
+unlock:
+	unlock_page(page);
+	/* Nothing submitted - we have to end page writeback */
+	if (!nr_submitted)
+		end_page_writeback(page);
+	return ret;
+}
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
new file mode 100644
index 000000000..f014c5e47
--- /dev/null
+++ b/fs/ext4/readpage.c
@@ -0,0 +1,440 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/readpage.c
+ *
+ * Copyright (C) 2002, Linus Torvalds.
+ * Copyright (C) 2015, Google, Inc.
+ *
+ * This was originally taken from fs/mpage.c
+ *
+ * The ext4_mpage_readpages() function here is intended to
+ * replace mpage_readahead() in the general case, not just for
+ * encrypted files.  It has some limitations (see below), where it
+ * will fall back to read_block_full_page(), but these limitations
+ * should only be hit when page_size != block_size.
+ *
+ * This will allow us to attach a callback function to support ext4
+ * encryption.
+ *
+ * If anything unusual happens, such as:
+ *
+ * - encountering a page which has buffers
+ * - encountering a page which has a non-hole after a hole
+ * - encountering a page with non-contiguous blocks
+ *
+ * then this code just gives up and calls the buffer_head-based read function.
+ * It does handle a page which has holes at the end - that is a common case:
+ * the end-of-file on blocksize < PAGE_SIZE setups.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/kdev_t.h>
+#include <linux/gfp.h>
+#include <linux/bio.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/blkdev.h>
+#include <linux/highmem.h>
+#include <linux/prefetch.h>
+#include <linux/mpage.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/pagevec.h>
+#include <linux/cleancache.h>
+
+#include "ext4.h"
+
+#define NUM_PREALLOC_POST_READ_CTXS	128
+
+static struct kmem_cache *bio_post_read_ctx_cache;
+static mempool_t *bio_post_read_ctx_pool;
+
+/* postprocessing steps for read bios */
+enum bio_post_read_step {
+	STEP_INITIAL = 0,
+	STEP_DECRYPT,
+	STEP_VERITY,
+	STEP_MAX,
+};
+
+struct bio_post_read_ctx {
+	struct bio *bio;
+	struct work_struct work;
+	unsigned int cur_step;
+	unsigned int enabled_steps;
+};
+
+static void __read_end_io(struct bio *bio)
+{
+	struct page *page;
+	struct bio_vec *bv;
+	struct bvec_iter_all iter_all;
+
+	bio_for_each_segment_all(bv, bio, iter_all) {
+		page = bv->bv_page;
+
+		/* PG_error was set if any post_read step failed */
+		if (bio->bi_status || PageError(page)) {
+			ClearPageUptodate(page);
+			/* will re-read again later */
+			ClearPageError(page);
+		} else {
+			SetPageUptodate(page);
+		}
+		unlock_page(page);
+	}
+	if (bio->bi_private)
+		mempool_free(bio->bi_private, bio_post_read_ctx_pool);
+	bio_put(bio);
+}
+
+static void bio_post_read_processing(struct bio_post_read_ctx *ctx);
+
+static void decrypt_work(struct work_struct *work)
+{
+	struct bio_post_read_ctx *ctx =
+		container_of(work, struct bio_post_read_ctx, work);
+
+	fscrypt_decrypt_bio(ctx->bio);
+
+	bio_post_read_processing(ctx);
+}
+
+static void verity_work(struct work_struct *work)
+{
+	struct bio_post_read_ctx *ctx =
+		container_of(work, struct bio_post_read_ctx, work);
+	struct bio *bio = ctx->bio;
+
+	/*
+	 * fsverity_verify_bio() may call readpages() again, and although verity
+	 * will be disabled for that, decryption may still be needed, causing
+	 * another bio_post_read_ctx to be allocated.  So to guarantee that
+	 * mempool_alloc() never deadlocks we must free the current ctx first.
+	 * This is safe because verity is the last post-read step.
+	 */
+	BUILD_BUG_ON(STEP_VERITY + 1 != STEP_MAX);
+	mempool_free(ctx, bio_post_read_ctx_pool);
+	bio->bi_private = NULL;
+
+	fsverity_verify_bio(bio);
+
+	__read_end_io(bio);
+}
+
+static void bio_post_read_processing(struct bio_post_read_ctx *ctx)
+{
+	/*
+	 * We use different work queues for decryption and for verity because
+	 * verity may require reading metadata pages that need decryption, and
+	 * we shouldn't recurse to the same workqueue.
+	 */
+	switch (++ctx->cur_step) {
+	case STEP_DECRYPT:
+		if (ctx->enabled_steps & (1 << STEP_DECRYPT)) {
+			INIT_WORK(&ctx->work, decrypt_work);
+			fscrypt_enqueue_decrypt_work(&ctx->work);
+			return;
+		}
+		ctx->cur_step++;
+		fallthrough;
+	case STEP_VERITY:
+		if (ctx->enabled_steps & (1 << STEP_VERITY)) {
+			INIT_WORK(&ctx->work, verity_work);
+			fsverity_enqueue_verify_work(&ctx->work);
+			return;
+		}
+		ctx->cur_step++;
+		fallthrough;
+	default:
+		__read_end_io(ctx->bio);
+	}
+}
+
+static bool bio_post_read_required(struct bio *bio)
+{
+	return bio->bi_private && !bio->bi_status;
+}
+
+/*
+ * I/O completion handler for multipage BIOs.
+ *
+ * The mpage code never puts partial pages into a BIO (except for end-of-file).
+ * If a page does not map to a contiguous run of blocks then it simply falls
+ * back to block_read_full_page().
+ *
+ * Why is this?  If a page's completion depends on a number of different BIOs
+ * which can complete in any order (or at the same time) then determining the
+ * status of that page is hard.  See end_buffer_async_read() for the details.
+ * There is no point in duplicating all that complexity.
+ */
+static void mpage_end_io(struct bio *bio)
+{
+	if (bio_post_read_required(bio)) {
+		struct bio_post_read_ctx *ctx = bio->bi_private;
+
+		ctx->cur_step = STEP_INITIAL;
+		bio_post_read_processing(ctx);
+		return;
+	}
+	__read_end_io(bio);
+}
+
+static inline bool ext4_need_verity(const struct inode *inode, pgoff_t idx)
+{
+	return fsverity_active(inode) &&
+	       idx < DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
+}
+
+static void ext4_set_bio_post_read_ctx(struct bio *bio,
+				       const struct inode *inode,
+				       pgoff_t first_idx)
+{
+	unsigned int post_read_steps = 0;
+
+	if (fscrypt_inode_uses_fs_layer_crypto(inode))
+		post_read_steps |= 1 << STEP_DECRYPT;
+
+	if (ext4_need_verity(inode, first_idx))
+		post_read_steps |= 1 << STEP_VERITY;
+
+	if (post_read_steps) {
+		/* Due to the mempool, this never fails. */
+		struct bio_post_read_ctx *ctx =
+			mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS);
+
+		ctx->bio = bio;
+		ctx->enabled_steps = post_read_steps;
+		bio->bi_private = ctx;
+	}
+}
+
+static inline loff_t ext4_readpage_limit(struct inode *inode)
+{
+	if (IS_ENABLED(CONFIG_FS_VERITY) &&
+	    (IS_VERITY(inode) || ext4_verity_in_progress(inode)))
+		return inode->i_sb->s_maxbytes;
+
+	return i_size_read(inode);
+}
+
+int ext4_mpage_readpages(struct inode *inode,
+		struct readahead_control *rac, struct page *page)
+{
+	struct bio *bio = NULL;
+	sector_t last_block_in_bio = 0;
+
+	const unsigned blkbits = inode->i_blkbits;
+	const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
+	const unsigned blocksize = 1 << blkbits;
+	sector_t next_block;
+	sector_t block_in_file;
+	sector_t last_block;
+	sector_t last_block_in_file;
+	sector_t blocks[MAX_BUF_PER_PAGE];
+	unsigned page_block;
+	struct block_device *bdev = inode->i_sb->s_bdev;
+	int length;
+	unsigned relative_block = 0;
+	struct ext4_map_blocks map;
+	unsigned int nr_pages = rac ? readahead_count(rac) : 1;
+
+	map.m_pblk = 0;
+	map.m_lblk = 0;
+	map.m_len = 0;
+	map.m_flags = 0;
+
+	for (; nr_pages; nr_pages--) {
+		int fully_mapped = 1;
+		unsigned first_hole = blocks_per_page;
+
+		if (rac) {
+			page = readahead_page(rac);
+			prefetchw(&page->flags);
+		}
+
+		if (page_has_buffers(page))
+			goto confused;
+
+		block_in_file = next_block =
+			(sector_t)page->index << (PAGE_SHIFT - blkbits);
+		last_block = block_in_file + nr_pages * blocks_per_page;
+		last_block_in_file = (ext4_readpage_limit(inode) +
+				      blocksize - 1) >> blkbits;
+		if (last_block > last_block_in_file)
+			last_block = last_block_in_file;
+		page_block = 0;
+
+		/*
+		 * Map blocks using the previous result first.
+		 */
+		if ((map.m_flags & EXT4_MAP_MAPPED) &&
+		    block_in_file > map.m_lblk &&
+		    block_in_file < (map.m_lblk + map.m_len)) {
+			unsigned map_offset = block_in_file - map.m_lblk;
+			unsigned last = map.m_len - map_offset;
+
+			for (relative_block = 0; ; relative_block++) {
+				if (relative_block == last) {
+					/* needed? */
+					map.m_flags &= ~EXT4_MAP_MAPPED;
+					break;
+				}
+				if (page_block == blocks_per_page)
+					break;
+				blocks[page_block] = map.m_pblk + map_offset +
+					relative_block;
+				page_block++;
+				block_in_file++;
+			}
+		}
+
+		/*
+		 * Then do more ext4_map_blocks() calls until we are
+		 * done with this page.
+		 */
+		while (page_block < blocks_per_page) {
+			if (block_in_file < last_block) {
+				map.m_lblk = block_in_file;
+				map.m_len = last_block - block_in_file;
+
+				if (ext4_map_blocks(NULL, inode, &map, 0) < 0) {
+				set_error_page:
+					SetPageError(page);
+					zero_user_segment(page, 0,
+							  PAGE_SIZE);
+					unlock_page(page);
+					goto next_page;
+				}
+			}
+			if ((map.m_flags & EXT4_MAP_MAPPED) == 0) {
+				fully_mapped = 0;
+				if (first_hole == blocks_per_page)
+					first_hole = page_block;
+				page_block++;
+				block_in_file++;
+				continue;
+			}
+			if (first_hole != blocks_per_page)
+				goto confused;		/* hole -> non-hole */
+
+			/* Contiguous blocks? */
+			if (page_block && blocks[page_block-1] != map.m_pblk-1)
+				goto confused;
+			for (relative_block = 0; ; relative_block++) {
+				if (relative_block == map.m_len) {
+					/* needed? */
+					map.m_flags &= ~EXT4_MAP_MAPPED;
+					break;
+				} else if (page_block == blocks_per_page)
+					break;
+				blocks[page_block] = map.m_pblk+relative_block;
+				page_block++;
+				block_in_file++;
+			}
+		}
+		if (first_hole != blocks_per_page) {
+			zero_user_segment(page, first_hole << blkbits,
+					  PAGE_SIZE);
+			if (first_hole == 0) {
+				if (ext4_need_verity(inode, page->index) &&
+				    !fsverity_verify_page(page))
+					goto set_error_page;
+				SetPageUptodate(page);
+				unlock_page(page);
+				goto next_page;
+			}
+		} else if (fully_mapped) {
+			SetPageMappedToDisk(page);
+		}
+		if (fully_mapped && blocks_per_page == 1 &&
+		    !PageUptodate(page) && cleancache_get_page(page) == 0) {
+			SetPageUptodate(page);
+			goto confused;
+		}
+
+		/*
+		 * This page will go to BIO.  Do we need to send this
+		 * BIO off first?
+		 */
+		if (bio && (last_block_in_bio != blocks[0] - 1 ||
+			    !fscrypt_mergeable_bio(bio, inode, next_block))) {
+		submit_and_realloc:
+			submit_bio(bio);
+			bio = NULL;
+		}
+		if (bio == NULL) {
+			/*
+			 * bio_alloc will _always_ be able to allocate a bio if
+			 * __GFP_DIRECT_RECLAIM is set, see bio_alloc_bioset().
+			 */
+			bio = bio_alloc(GFP_KERNEL,
+				min_t(int, nr_pages, BIO_MAX_PAGES));
+			fscrypt_set_bio_crypt_ctx(bio, inode, next_block,
+						  GFP_KERNEL);
+			ext4_set_bio_post_read_ctx(bio, inode, page->index);
+			bio_set_dev(bio, bdev);
+			bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
+			bio->bi_end_io = mpage_end_io;
+			bio_set_op_attrs(bio, REQ_OP_READ,
+						rac ? REQ_RAHEAD : 0);
+		}
+
+		length = first_hole << blkbits;
+		if (bio_add_page(bio, page, length, 0) < length)
+			goto submit_and_realloc;
+
+		if (((map.m_flags & EXT4_MAP_BOUNDARY) &&
+		     (relative_block == map.m_len)) ||
+		    (first_hole != blocks_per_page)) {
+			submit_bio(bio);
+			bio = NULL;
+		} else
+			last_block_in_bio = blocks[blocks_per_page - 1];
+		goto next_page;
+	confused:
+		if (bio) {
+			submit_bio(bio);
+			bio = NULL;
+		}
+		if (!PageUptodate(page))
+			block_read_full_page(page, ext4_get_block);
+		else
+			unlock_page(page);
+	next_page:
+		if (rac)
+			put_page(page);
+	}
+	if (bio)
+		submit_bio(bio);
+	return 0;
+}
+
+int __init ext4_init_post_read_processing(void)
+{
+	bio_post_read_ctx_cache =
+		kmem_cache_create("ext4_bio_post_read_ctx",
+				  sizeof(struct bio_post_read_ctx), 0, 0, NULL);
+	if (!bio_post_read_ctx_cache)
+		goto fail;
+	bio_post_read_ctx_pool =
+		mempool_create_slab_pool(NUM_PREALLOC_POST_READ_CTXS,
+					 bio_post_read_ctx_cache);
+	if (!bio_post_read_ctx_pool)
+		goto fail_free_cache;
+	return 0;
+
+fail_free_cache:
+	kmem_cache_destroy(bio_post_read_ctx_cache);
+fail:
+	return -ENOMEM;
+}
+
+void ext4_exit_post_read_processing(void)
+{
+	mempool_destroy(bio_post_read_ctx_pool);
+	kmem_cache_destroy(bio_post_read_ctx_cache);
+}
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
new file mode 100644
index 000000000..9b4199a1e
--- /dev/null
+++ b/fs/ext4/resize.c
@@ -0,0 +1,2125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/resize.c
+ *
+ * Support for resizing an ext4 filesystem while it is mounted.
+ *
+ * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
+ *
+ * This could probably be made into a module, because it is not often in use.
+ */
+
+
+#define EXT4FS_DEBUG
+
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+#include "ext4_jbd2.h"
+
+struct ext4_rcu_ptr {
+	struct rcu_head rcu;
+	void *ptr;
+};
+
+static void ext4_rcu_ptr_callback(struct rcu_head *head)
+{
+	struct ext4_rcu_ptr *ptr;
+
+	ptr = container_of(head, struct ext4_rcu_ptr, rcu);
+	kvfree(ptr->ptr);
+	kfree(ptr);
+}
+
+void ext4_kvfree_array_rcu(void *to_free)
+{
+	struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
+
+	if (ptr) {
+		ptr->ptr = to_free;
+		call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
+		return;
+	}
+	synchronize_rcu();
+	kvfree(to_free);
+}
+
+int ext4_resize_begin(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int ret = 0;
+
+	if (!capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
+	/*
+	 * If the reserved GDT blocks is non-zero, the resize_inode feature
+	 * should always be set.
+	 */
+	if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
+	    !ext4_has_feature_resize_inode(sb)) {
+		ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * If we are not using the primary superblock/GDT copy don't resize,
+         * because the user tools have no way of handling this.  Probably a
+         * bad time to do it anyways.
+         */
+	if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
+	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
+		ext4_warning(sb, "won't resize using backup superblock at %llu",
+			(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
+		return -EPERM;
+	}
+
+	/*
+	 * We are not allowed to do online-resizing on a filesystem mounted
+	 * with error, because it can destroy the filesystem easily.
+	 */
+	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
+		ext4_warning(sb, "There are errors in the filesystem, "
+			     "so online resizing is not allowed");
+		return -EPERM;
+	}
+
+	if (ext4_has_feature_sparse_super2(sb)) {
+		ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
+		return -EOPNOTSUPP;
+	}
+
+	if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
+				  &EXT4_SB(sb)->s_ext4_flags))
+		ret = -EBUSY;
+
+	return ret;
+}
+
+void ext4_resize_end(struct super_block *sb)
+{
+	clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
+	smp_mb__after_atomic();
+}
+
+static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
+					     ext4_group_t group) {
+	return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
+	       EXT4_DESC_PER_BLOCK_BITS(sb);
+}
+
+static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
+					     ext4_group_t group) {
+	group = ext4_meta_bg_first_group(sb, group);
+	return ext4_group_first_block_no(sb, group);
+}
+
+static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
+						ext4_group_t group) {
+	ext4_grpblk_t overhead;
+	overhead = ext4_bg_num_gdb(sb, group);
+	if (ext4_bg_has_super(sb, group))
+		overhead += 1 +
+			  le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
+	return overhead;
+}
+
+#define outside(b, first, last)	((b) < (first) || (b) >= (last))
+#define inside(b, first, last)	((b) >= (first) && (b) < (last))
+
+static int verify_group_input(struct super_block *sb,
+			      struct ext4_new_group_data *input)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	ext4_fsblk_t start = ext4_blocks_count(es);
+	ext4_fsblk_t end = start + input->blocks_count;
+	ext4_group_t group = input->group;
+	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
+	unsigned overhead;
+	ext4_fsblk_t metaend;
+	struct buffer_head *bh = NULL;
+	ext4_grpblk_t free_blocks_count, offset;
+	int err = -EINVAL;
+
+	if (group != sbi->s_groups_count) {
+		ext4_warning(sb, "Cannot add at group %u (only %u groups)",
+			     input->group, sbi->s_groups_count);
+		return -EINVAL;
+	}
+
+	overhead = ext4_group_overhead_blocks(sb, group);
+	metaend = start + overhead;
+	input->free_clusters_count = free_blocks_count =
+		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
+		       "(%d free, %u reserved)\n",
+		       ext4_bg_has_super(sb, input->group) ? "normal" :
+		       "no-super", input->group, input->blocks_count,
+		       free_blocks_count, input->reserved_blocks);
+
+	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
+	if (offset != 0)
+			ext4_warning(sb, "Last group not full");
+	else if (input->reserved_blocks > input->blocks_count / 5)
+		ext4_warning(sb, "Reserved blocks too high (%u)",
+			     input->reserved_blocks);
+	else if (free_blocks_count < 0)
+		ext4_warning(sb, "Bad blocks count %u",
+			     input->blocks_count);
+	else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
+		err = PTR_ERR(bh);
+		bh = NULL;
+		ext4_warning(sb, "Cannot read last block (%llu)",
+			     end - 1);
+	} else if (outside(input->block_bitmap, start, end))
+		ext4_warning(sb, "Block bitmap not in group (block %llu)",
+			     (unsigned long long)input->block_bitmap);
+	else if (outside(input->inode_bitmap, start, end))
+		ext4_warning(sb, "Inode bitmap not in group (block %llu)",
+			     (unsigned long long)input->inode_bitmap);
+	else if (outside(input->inode_table, start, end) ||
+		 outside(itend - 1, start, end))
+		ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
+			     (unsigned long long)input->inode_table, itend - 1);
+	else if (input->inode_bitmap == input->block_bitmap)
+		ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
+			     (unsigned long long)input->block_bitmap);
+	else if (inside(input->block_bitmap, input->inode_table, itend))
+		ext4_warning(sb, "Block bitmap (%llu) in inode table "
+			     "(%llu-%llu)",
+			     (unsigned long long)input->block_bitmap,
+			     (unsigned long long)input->inode_table, itend - 1);
+	else if (inside(input->inode_bitmap, input->inode_table, itend))
+		ext4_warning(sb, "Inode bitmap (%llu) in inode table "
+			     "(%llu-%llu)",
+			     (unsigned long long)input->inode_bitmap,
+			     (unsigned long long)input->inode_table, itend - 1);
+	else if (inside(input->block_bitmap, start, metaend))
+		ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
+			     (unsigned long long)input->block_bitmap,
+			     start, metaend - 1);
+	else if (inside(input->inode_bitmap, start, metaend))
+		ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
+			     (unsigned long long)input->inode_bitmap,
+			     start, metaend - 1);
+	else if (inside(input->inode_table, start, metaend) ||
+		 inside(itend - 1, start, metaend))
+		ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
+			     "(%llu-%llu)",
+			     (unsigned long long)input->inode_table,
+			     itend - 1, start, metaend - 1);
+	else
+		err = 0;
+	brelse(bh);
+
+	return err;
+}
+
+/*
+ * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
+ * group each time.
+ */
+struct ext4_new_flex_group_data {
+	struct ext4_new_group_data *groups;	/* new_group_data for groups
+						   in the flex group */
+	__u16 *bg_flags;			/* block group flags of groups
+						   in @groups */
+	ext4_group_t count;			/* number of groups in @groups
+						 */
+};
+
+/*
+ * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
+ * @flexbg_size.
+ *
+ * Returns NULL on failure otherwise address of the allocated structure.
+ */
+static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
+{
+	struct ext4_new_flex_group_data *flex_gd;
+
+	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
+	if (flex_gd == NULL)
+		goto out3;
+
+	if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
+		goto out2;
+	flex_gd->count = flexbg_size;
+
+	flex_gd->groups = kmalloc_array(flexbg_size,
+					sizeof(struct ext4_new_group_data),
+					GFP_NOFS);
+	if (flex_gd->groups == NULL)
+		goto out2;
+
+	flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
+					  GFP_NOFS);
+	if (flex_gd->bg_flags == NULL)
+		goto out1;
+
+	return flex_gd;
+
+out1:
+	kfree(flex_gd->groups);
+out2:
+	kfree(flex_gd);
+out3:
+	return NULL;
+}
+
+static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
+{
+	kfree(flex_gd->bg_flags);
+	kfree(flex_gd->groups);
+	kfree(flex_gd);
+}
+
+/*
+ * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
+ * and inode tables for a flex group.
+ *
+ * This function is used by 64bit-resize.  Note that this function allocates
+ * group tables from the 1st group of groups contained by @flexgd, which may
+ * be a partial of a flex group.
+ *
+ * @sb: super block of fs to which the groups belongs
+ *
+ * Returns 0 on a successful allocation of the metadata blocks in the
+ * block group.
+ */
+static int ext4_alloc_group_tables(struct super_block *sb,
+				struct ext4_new_flex_group_data *flex_gd,
+				int flexbg_size)
+{
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	ext4_fsblk_t start_blk;
+	ext4_fsblk_t last_blk;
+	ext4_group_t src_group;
+	ext4_group_t bb_index = 0;
+	ext4_group_t ib_index = 0;
+	ext4_group_t it_index = 0;
+	ext4_group_t group;
+	ext4_group_t last_group;
+	unsigned overhead;
+	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
+	int i;
+
+	BUG_ON(flex_gd->count == 0 || group_data == NULL);
+
+	src_group = group_data[0].group;
+	last_group  = src_group + flex_gd->count - 1;
+
+	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
+	       (last_group & ~(flexbg_size - 1))));
+next_group:
+	group = group_data[0].group;
+	if (src_group >= group_data[0].group + flex_gd->count)
+		return -ENOSPC;
+	start_blk = ext4_group_first_block_no(sb, src_group);
+	last_blk = start_blk + group_data[src_group - group].blocks_count;
+
+	overhead = ext4_group_overhead_blocks(sb, src_group);
+
+	start_blk += overhead;
+
+	/* We collect contiguous blocks as much as possible. */
+	src_group++;
+	for (; src_group <= last_group; src_group++) {
+		overhead = ext4_group_overhead_blocks(sb, src_group);
+		if (overhead == 0)
+			last_blk += group_data[src_group - group].blocks_count;
+		else
+			break;
+	}
+
+	/* Allocate block bitmaps */
+	for (; bb_index < flex_gd->count; bb_index++) {
+		if (start_blk >= last_blk)
+			goto next_group;
+		group_data[bb_index].block_bitmap = start_blk++;
+		group = ext4_get_group_number(sb, start_blk - 1);
+		group -= group_data[0].group;
+		group_data[group].mdata_blocks++;
+		flex_gd->bg_flags[group] &= uninit_mask;
+	}
+
+	/* Allocate inode bitmaps */
+	for (; ib_index < flex_gd->count; ib_index++) {
+		if (start_blk >= last_blk)
+			goto next_group;
+		group_data[ib_index].inode_bitmap = start_blk++;
+		group = ext4_get_group_number(sb, start_blk - 1);
+		group -= group_data[0].group;
+		group_data[group].mdata_blocks++;
+		flex_gd->bg_flags[group] &= uninit_mask;
+	}
+
+	/* Allocate inode tables */
+	for (; it_index < flex_gd->count; it_index++) {
+		unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
+		ext4_fsblk_t next_group_start;
+
+		if (start_blk + itb > last_blk)
+			goto next_group;
+		group_data[it_index].inode_table = start_blk;
+		group = ext4_get_group_number(sb, start_blk);
+		next_group_start = ext4_group_first_block_no(sb, group + 1);
+		group -= group_data[0].group;
+
+		if (start_blk + itb > next_group_start) {
+			flex_gd->bg_flags[group + 1] &= uninit_mask;
+			overhead = start_blk + itb - next_group_start;
+			group_data[group + 1].mdata_blocks += overhead;
+			itb -= overhead;
+		}
+
+		group_data[group].mdata_blocks += itb;
+		flex_gd->bg_flags[group] &= uninit_mask;
+		start_blk += EXT4_SB(sb)->s_itb_per_group;
+	}
+
+	/* Update free clusters count to exclude metadata blocks */
+	for (i = 0; i < flex_gd->count; i++) {
+		group_data[i].free_clusters_count -=
+				EXT4_NUM_B2C(EXT4_SB(sb),
+					     group_data[i].mdata_blocks);
+	}
+
+	if (test_opt(sb, DEBUG)) {
+		int i;
+		group = group_data[0].group;
+
+		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
+		       "%d groups, flexbg size is %d:\n", flex_gd->count,
+		       flexbg_size);
+
+		for (i = 0; i < flex_gd->count; i++) {
+			ext4_debug(
+			       "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
+			       ext4_bg_has_super(sb, group + i) ? "normal" :
+			       "no-super", group + i,
+			       group_data[i].blocks_count,
+			       group_data[i].free_clusters_count,
+			       group_data[i].mdata_blocks);
+		}
+	}
+	return 0;
+}
+
+static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
+				  ext4_fsblk_t blk)
+{
+	struct buffer_head *bh;
+	int err;
+
+	bh = sb_getblk(sb, blk);
+	if (unlikely(!bh))
+		return ERR_PTR(-ENOMEM);
+	BUFFER_TRACE(bh, "get_write_access");
+	if ((err = ext4_journal_get_write_access(handle, bh))) {
+		brelse(bh);
+		bh = ERR_PTR(err);
+	} else {
+		memset(bh->b_data, 0, sb->s_blocksize);
+		set_buffer_uptodate(bh);
+	}
+
+	return bh;
+}
+
+static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
+{
+	return ext4_journal_ensure_credits_fn(handle, credits,
+		EXT4_MAX_TRANS_DATA, 0, 0);
+}
+
+/*
+ * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
+ *
+ * Helper function for ext4_setup_new_group_blocks() which set .
+ *
+ * @sb: super block
+ * @handle: journal handle
+ * @flex_gd: flex group data
+ */
+static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
+			struct ext4_new_flex_group_data *flex_gd,
+			ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_group_t count = last_cluster - first_cluster + 1;
+	ext4_group_t count2;
+
+	ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
+		   last_cluster);
+	for (count2 = count; count > 0;
+	     count -= count2, first_cluster += count2) {
+		ext4_fsblk_t start;
+		struct buffer_head *bh;
+		ext4_group_t group;
+		int err;
+
+		group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
+		start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
+		group -= flex_gd->groups[0].group;
+
+		count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
+		if (count2 > count)
+			count2 = count;
+
+		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
+			BUG_ON(flex_gd->count > 1);
+			continue;
+		}
+
+		err = ext4_resize_ensure_credits_batch(handle, 1);
+		if (err < 0)
+			return err;
+
+		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
+		if (unlikely(!bh))
+			return -ENOMEM;
+
+		BUFFER_TRACE(bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, bh);
+		if (err) {
+			brelse(bh);
+			return err;
+		}
+		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
+			   first_cluster, first_cluster - start, count2);
+		ext4_set_bits(bh->b_data, first_cluster - start, count2);
+
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		brelse(bh);
+		if (unlikely(err))
+			return err;
+	}
+
+	return 0;
+}
+
+/*
+ * Set up the block and inode bitmaps, and the inode table for the new groups.
+ * This doesn't need to be part of the main transaction, since we are only
+ * changing blocks outside the actual filesystem.  We still do journaling to
+ * ensure the recovery is correct in case of a failure just after resize.
+ * If any part of this fails, we simply abort the resize.
+ *
+ * setup_new_flex_group_blocks handles a flex group as follow:
+ *  1. copy super block and GDT, and initialize group tables if necessary.
+ *     In this step, we only set bits in blocks bitmaps for blocks taken by
+ *     super block and GDT.
+ *  2. allocate group tables in block bitmaps, that is, set bits in block
+ *     bitmap for blocks taken by group tables.
+ */
+static int setup_new_flex_group_blocks(struct super_block *sb,
+				struct ext4_new_flex_group_data *flex_gd)
+{
+	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
+	ext4_fsblk_t start;
+	ext4_fsblk_t block;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	__u16 *bg_flags = flex_gd->bg_flags;
+	handle_t *handle;
+	ext4_group_t group, count;
+	struct buffer_head *bh = NULL;
+	int reserved_gdb, i, j, err = 0, err2;
+	int meta_bg;
+
+	BUG_ON(!flex_gd->count || !group_data ||
+	       group_data[0].group != sbi->s_groups_count);
+
+	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
+	meta_bg = ext4_has_feature_meta_bg(sb);
+
+	/* This transaction may be extended/restarted along the way */
+	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	group = group_data[0].group;
+	for (i = 0; i < flex_gd->count; i++, group++) {
+		unsigned long gdblocks;
+		ext4_grpblk_t overhead;
+
+		gdblocks = ext4_bg_num_gdb(sb, group);
+		start = ext4_group_first_block_no(sb, group);
+
+		if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
+			goto handle_itb;
+
+		if (meta_bg == 1)
+			goto handle_itb;
+
+		block = start + ext4_bg_has_super(sb, group);
+		/* Copy all of the GDT blocks into the backup in this group */
+		for (j = 0; j < gdblocks; j++, block++) {
+			struct buffer_head *gdb;
+
+			ext4_debug("update backup group %#04llx\n", block);
+			err = ext4_resize_ensure_credits_batch(handle, 1);
+			if (err < 0)
+				goto out;
+
+			gdb = sb_getblk(sb, block);
+			if (unlikely(!gdb)) {
+				err = -ENOMEM;
+				goto out;
+			}
+
+			BUFFER_TRACE(gdb, "get_write_access");
+			err = ext4_journal_get_write_access(handle, gdb);
+			if (err) {
+				brelse(gdb);
+				goto out;
+			}
+			memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
+				s_group_desc, j)->b_data, gdb->b_size);
+			set_buffer_uptodate(gdb);
+
+			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
+			if (unlikely(err)) {
+				brelse(gdb);
+				goto out;
+			}
+			brelse(gdb);
+		}
+
+		/* Zero out all of the reserved backup group descriptor
+		 * table blocks
+		 */
+		if (ext4_bg_has_super(sb, group)) {
+			err = sb_issue_zeroout(sb, gdblocks + start + 1,
+					reserved_gdb, GFP_NOFS);
+			if (err)
+				goto out;
+		}
+
+handle_itb:
+		/* Initialize group tables of the grop @group */
+		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
+			goto handle_bb;
+
+		/* Zero out all of the inode table blocks */
+		block = group_data[i].inode_table;
+		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
+			   block, sbi->s_itb_per_group);
+		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
+				       GFP_NOFS);
+		if (err)
+			goto out;
+
+handle_bb:
+		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
+			goto handle_ib;
+
+		/* Initialize block bitmap of the @group */
+		block = group_data[i].block_bitmap;
+		err = ext4_resize_ensure_credits_batch(handle, 1);
+		if (err < 0)
+			goto out;
+
+		bh = bclean(handle, sb, block);
+		if (IS_ERR(bh)) {
+			err = PTR_ERR(bh);
+			goto out;
+		}
+		overhead = ext4_group_overhead_blocks(sb, group);
+		if (overhead != 0) {
+			ext4_debug("mark backup superblock %#04llx (+0)\n",
+				   start);
+			ext4_set_bits(bh->b_data, 0,
+				      EXT4_NUM_B2C(sbi, overhead));
+		}
+		ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
+				     sb->s_blocksize * 8, bh->b_data);
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		brelse(bh);
+		if (err)
+			goto out;
+
+handle_ib:
+		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
+			continue;
+
+		/* Initialize inode bitmap of the @group */
+		block = group_data[i].inode_bitmap;
+		err = ext4_resize_ensure_credits_batch(handle, 1);
+		if (err < 0)
+			goto out;
+		/* Mark unused entries in inode bitmap used */
+		bh = bclean(handle, sb, block);
+		if (IS_ERR(bh)) {
+			err = PTR_ERR(bh);
+			goto out;
+		}
+
+		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
+				     sb->s_blocksize * 8, bh->b_data);
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		brelse(bh);
+		if (err)
+			goto out;
+	}
+
+	/* Mark group tables in block bitmap */
+	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
+		count = group_table_count[j];
+		start = (&group_data[0].block_bitmap)[j];
+		block = start;
+		for (i = 1; i < flex_gd->count; i++) {
+			block += group_table_count[j];
+			if (block == (&group_data[i].block_bitmap)[j]) {
+				count += group_table_count[j];
+				continue;
+			}
+			err = set_flexbg_block_bitmap(sb, handle,
+						      flex_gd,
+						      EXT4_B2C(sbi, start),
+						      EXT4_B2C(sbi,
+							       start + count
+							       - 1));
+			if (err)
+				goto out;
+			count = group_table_count[j];
+			start = (&group_data[i].block_bitmap)[j];
+			block = start;
+		}
+
+		if (count) {
+			err = set_flexbg_block_bitmap(sb, handle,
+						      flex_gd,
+						      EXT4_B2C(sbi, start),
+						      EXT4_B2C(sbi,
+							       start + count
+							       - 1));
+			if (err)
+				goto out;
+		}
+	}
+
+out:
+	err2 = ext4_journal_stop(handle);
+	if (err2 && !err)
+		err = err2;
+
+	return err;
+}
+
+/*
+ * Iterate through the groups which hold BACKUP superblock/GDT copies in an
+ * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
+ * calling this for the first time.  In a sparse filesystem it will be the
+ * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
+ * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
+ */
+static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
+				  unsigned *five, unsigned *seven)
+{
+	unsigned *min = three;
+	int mult = 3;
+	unsigned ret;
+
+	if (!ext4_has_feature_sparse_super(sb)) {
+		ret = *min;
+		*min += 1;
+		return ret;
+	}
+
+	if (*five < *min) {
+		min = five;
+		mult = 5;
+	}
+	if (*seven < *min) {
+		min = seven;
+		mult = 7;
+	}
+
+	ret = *min;
+	*min *= mult;
+
+	return ret;
+}
+
+/*
+ * Check that all of the backup GDT blocks are held in the primary GDT block.
+ * It is assumed that they are stored in group order.  Returns the number of
+ * groups in current filesystem that have BACKUPS, or -ve error code.
+ */
+static int verify_reserved_gdb(struct super_block *sb,
+			       ext4_group_t end,
+			       struct buffer_head *primary)
+{
+	const ext4_fsblk_t blk = primary->b_blocknr;
+	unsigned three = 1;
+	unsigned five = 5;
+	unsigned seven = 7;
+	unsigned grp;
+	__le32 *p = (__le32 *)primary->b_data;
+	int gdbackups = 0;
+
+	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
+		if (le32_to_cpu(*p++) !=
+		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
+			ext4_warning(sb, "reserved GDT %llu"
+				     " missing grp %d (%llu)",
+				     blk, grp,
+				     grp *
+				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
+				     blk);
+			return -EINVAL;
+		}
+		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
+			return -EFBIG;
+	}
+
+	return gdbackups;
+}
+
+/*
+ * Called when we need to bring a reserved group descriptor table block into
+ * use from the resize inode.  The primary copy of the new GDT block currently
+ * is an indirect block (under the double indirect block in the resize inode).
+ * The new backup GDT blocks will be stored as leaf blocks in this indirect
+ * block, in group order.  Even though we know all the block numbers we need,
+ * we check to ensure that the resize inode has actually reserved these blocks.
+ *
+ * Don't need to update the block bitmaps because the blocks are still in use.
+ *
+ * We get all of the error cases out of the way, so that we are sure to not
+ * fail once we start modifying the data on disk, because JBD has no rollback.
+ */
+static int add_new_gdb(handle_t *handle, struct inode *inode,
+		       ext4_group_t group)
+{
+	struct super_block *sb = inode->i_sb;
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
+	struct buffer_head **o_group_desc, **n_group_desc = NULL;
+	struct buffer_head *dind = NULL;
+	struct buffer_head *gdb_bh = NULL;
+	int gdbackups;
+	struct ext4_iloc iloc = { .bh = NULL };
+	__le32 *data;
+	int err;
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG
+		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
+		       gdb_num);
+
+	gdb_bh = ext4_sb_bread(sb, gdblock, 0);
+	if (IS_ERR(gdb_bh))
+		return PTR_ERR(gdb_bh);
+
+	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
+	if (gdbackups < 0) {
+		err = gdbackups;
+		goto errout;
+	}
+
+	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
+	dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
+	if (IS_ERR(dind)) {
+		err = PTR_ERR(dind);
+		dind = NULL;
+		goto errout;
+	}
+
+	data = (__le32 *)dind->b_data;
+	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
+		ext4_warning(sb, "new group %u GDT block %llu not reserved",
+			     group, gdblock);
+		err = -EINVAL;
+		goto errout;
+	}
+
+	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
+	if (unlikely(err))
+		goto errout;
+
+	BUFFER_TRACE(gdb_bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, gdb_bh);
+	if (unlikely(err))
+		goto errout;
+
+	BUFFER_TRACE(dind, "get_write_access");
+	err = ext4_journal_get_write_access(handle, dind);
+	if (unlikely(err)) {
+		ext4_std_error(sb, err);
+		goto errout;
+	}
+
+	/* ext4_reserve_inode_write() gets a reference on the iloc */
+	err = ext4_reserve_inode_write(handle, inode, &iloc);
+	if (unlikely(err))
+		goto errout;
+
+	n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
+				GFP_KERNEL);
+	if (!n_group_desc) {
+		err = -ENOMEM;
+		ext4_warning(sb, "not enough memory for %lu groups",
+			     gdb_num + 1);
+		goto errout;
+	}
+
+	/*
+	 * Finally, we have all of the possible failures behind us...
+	 *
+	 * Remove new GDT block from inode double-indirect block and clear out
+	 * the new GDT block for use (which also "frees" the backup GDT blocks
+	 * from the reserved inode).  We don't need to change the bitmaps for
+	 * these blocks, because they are marked as in-use from being in the
+	 * reserved inode, and will become GDT blocks (primary and backup).
+	 */
+	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
+	err = ext4_handle_dirty_metadata(handle, NULL, dind);
+	if (unlikely(err)) {
+		ext4_std_error(sb, err);
+		goto errout;
+	}
+	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
+			   (9 - EXT4_SB(sb)->s_cluster_bits);
+	ext4_mark_iloc_dirty(handle, inode, &iloc);
+	memset(gdb_bh->b_data, 0, sb->s_blocksize);
+	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
+	if (unlikely(err)) {
+		ext4_std_error(sb, err);
+		iloc.bh = NULL;
+		goto errout;
+	}
+	brelse(dind);
+
+	rcu_read_lock();
+	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
+	memcpy(n_group_desc, o_group_desc,
+	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
+	rcu_read_unlock();
+	n_group_desc[gdb_num] = gdb_bh;
+	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
+	EXT4_SB(sb)->s_gdb_count++;
+	ext4_kvfree_array_rcu(o_group_desc);
+
+	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
+	err = ext4_handle_dirty_super(handle, sb);
+	if (err)
+		ext4_std_error(sb, err);
+	return err;
+errout:
+	kvfree(n_group_desc);
+	brelse(iloc.bh);
+	brelse(dind);
+	brelse(gdb_bh);
+
+	ext4_debug("leaving with error %d\n", err);
+	return err;
+}
+
+/*
+ * add_new_gdb_meta_bg is the sister of add_new_gdb.
+ */
+static int add_new_gdb_meta_bg(struct super_block *sb,
+			       handle_t *handle, ext4_group_t group) {
+	ext4_fsblk_t gdblock;
+	struct buffer_head *gdb_bh;
+	struct buffer_head **o_group_desc, **n_group_desc;
+	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+	int err;
+
+	gdblock = ext4_meta_bg_first_block_no(sb, group) +
+		   ext4_bg_has_super(sb, group);
+	gdb_bh = ext4_sb_bread(sb, gdblock, 0);
+	if (IS_ERR(gdb_bh))
+		return PTR_ERR(gdb_bh);
+	n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
+				GFP_KERNEL);
+	if (!n_group_desc) {
+		brelse(gdb_bh);
+		err = -ENOMEM;
+		ext4_warning(sb, "not enough memory for %lu groups",
+			     gdb_num + 1);
+		return err;
+	}
+
+	rcu_read_lock();
+	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
+	memcpy(n_group_desc, o_group_desc,
+	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
+	rcu_read_unlock();
+	n_group_desc[gdb_num] = gdb_bh;
+
+	BUFFER_TRACE(gdb_bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, gdb_bh);
+	if (err) {
+		kvfree(n_group_desc);
+		brelse(gdb_bh);
+		return err;
+	}
+
+	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
+	EXT4_SB(sb)->s_gdb_count++;
+	ext4_kvfree_array_rcu(o_group_desc);
+	return err;
+}
+
+/*
+ * Called when we are adding a new group which has a backup copy of each of
+ * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
+ * We need to add these reserved backup GDT blocks to the resize inode, so
+ * that they are kept for future resizing and not allocated to files.
+ *
+ * Each reserved backup GDT block will go into a different indirect block.
+ * The indirect blocks are actually the primary reserved GDT blocks,
+ * so we know in advance what their block numbers are.  We only get the
+ * double-indirect block to verify it is pointing to the primary reserved
+ * GDT blocks so we don't overwrite a data block by accident.  The reserved
+ * backup GDT blocks are stored in their reserved primary GDT block.
+ */
+static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
+			      ext4_group_t group)
+{
+	struct super_block *sb = inode->i_sb;
+	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
+	int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
+	struct buffer_head **primary;
+	struct buffer_head *dind;
+	struct ext4_iloc iloc;
+	ext4_fsblk_t blk;
+	__le32 *data, *end;
+	int gdbackups = 0;
+	int res, i;
+	int err;
+
+	primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
+	if (!primary)
+		return -ENOMEM;
+
+	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
+	dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
+	if (IS_ERR(dind)) {
+		err = PTR_ERR(dind);
+		dind = NULL;
+		goto exit_free;
+	}
+
+	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
+	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
+					 EXT4_ADDR_PER_BLOCK(sb));
+	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
+
+	/* Get each reserved primary GDT block and verify it holds backups */
+	for (res = 0; res < reserved_gdb; res++, blk++) {
+		if (le32_to_cpu(*data) != blk) {
+			ext4_warning(sb, "reserved block %llu"
+				     " not at offset %ld",
+				     blk,
+				     (long)(data - (__le32 *)dind->b_data));
+			err = -EINVAL;
+			goto exit_bh;
+		}
+		primary[res] = ext4_sb_bread(sb, blk, 0);
+		if (IS_ERR(primary[res])) {
+			err = PTR_ERR(primary[res]);
+			primary[res] = NULL;
+			goto exit_bh;
+		}
+		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
+		if (gdbackups < 0) {
+			brelse(primary[res]);
+			err = gdbackups;
+			goto exit_bh;
+		}
+		if (++data >= end)
+			data = (__le32 *)dind->b_data;
+	}
+
+	for (i = 0; i < reserved_gdb; i++) {
+		BUFFER_TRACE(primary[i], "get_write_access");
+		if ((err = ext4_journal_get_write_access(handle, primary[i])))
+			goto exit_bh;
+	}
+
+	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
+		goto exit_bh;
+
+	/*
+	 * Finally we can add each of the reserved backup GDT blocks from
+	 * the new group to its reserved primary GDT block.
+	 */
+	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
+	for (i = 0; i < reserved_gdb; i++) {
+		int err2;
+		data = (__le32 *)primary[i]->b_data;
+		/* printk("reserving backup %lu[%u] = %lu\n",
+		       primary[i]->b_blocknr, gdbackups,
+		       blk + primary[i]->b_blocknr); */
+		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
+		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
+		if (!err)
+			err = err2;
+	}
+
+	inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
+	ext4_mark_iloc_dirty(handle, inode, &iloc);
+
+exit_bh:
+	while (--res >= 0)
+		brelse(primary[res]);
+	brelse(dind);
+
+exit_free:
+	kfree(primary);
+
+	return err;
+}
+
+/*
+ * Update the backup copies of the ext4 metadata.  These don't need to be part
+ * of the main resize transaction, because e2fsck will re-write them if there
+ * is a problem (basically only OOM will cause a problem).  However, we
+ * _should_ update the backups if possible, in case the primary gets trashed
+ * for some reason and we need to run e2fsck from a backup superblock.  The
+ * important part is that the new block and inode counts are in the backup
+ * superblocks, and the location of the new group metadata in the GDT backups.
+ *
+ * We do not need take the s_resize_lock for this, because these
+ * blocks are not otherwise touched by the filesystem code when it is
+ * mounted.  We don't need to worry about last changing from
+ * sbi->s_groups_count, because the worst that can happen is that we
+ * do not copy the full number of backups at this time.  The resize
+ * which changed s_groups_count will backup again.
+ */
+static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
+			   int size, int meta_bg)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_group_t last;
+	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
+	unsigned three = 1;
+	unsigned five = 5;
+	unsigned seven = 7;
+	ext4_group_t group = 0;
+	int rest = sb->s_blocksize - size;
+	handle_t *handle;
+	int err = 0, err2;
+
+	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
+	if (IS_ERR(handle)) {
+		group = 1;
+		err = PTR_ERR(handle);
+		goto exit_err;
+	}
+
+	if (meta_bg == 0) {
+		group = ext4_list_backups(sb, &three, &five, &seven);
+		last = sbi->s_groups_count;
+	} else {
+		group = ext4_get_group_number(sb, blk_off) + 1;
+		last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
+	}
+
+	while (group < sbi->s_groups_count) {
+		struct buffer_head *bh;
+		ext4_fsblk_t backup_block;
+
+		/* Out of journal space, and can't get more - abort - so sad */
+		err = ext4_resize_ensure_credits_batch(handle, 1);
+		if (err < 0)
+			break;
+
+		if (meta_bg == 0)
+			backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
+		else
+			backup_block = (ext4_group_first_block_no(sb, group) +
+					ext4_bg_has_super(sb, group));
+
+		bh = sb_getblk(sb, backup_block);
+		if (unlikely(!bh)) {
+			err = -ENOMEM;
+			break;
+		}
+		ext4_debug("update metadata backup %llu(+%llu)\n",
+			   backup_block, backup_block -
+			   ext4_group_first_block_no(sb, group));
+		BUFFER_TRACE(bh, "get_write_access");
+		if ((err = ext4_journal_get_write_access(handle, bh))) {
+			brelse(bh);
+			break;
+		}
+		lock_buffer(bh);
+		memcpy(bh->b_data, data, size);
+		if (rest)
+			memset(bh->b_data + size, 0, rest);
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (unlikely(err))
+			ext4_std_error(sb, err);
+		brelse(bh);
+
+		if (meta_bg == 0)
+			group = ext4_list_backups(sb, &three, &five, &seven);
+		else if (group == last)
+			break;
+		else
+			group = last;
+	}
+	if ((err2 = ext4_journal_stop(handle)) && !err)
+		err = err2;
+
+	/*
+	 * Ugh! Need to have e2fsck write the backup copies.  It is too
+	 * late to revert the resize, we shouldn't fail just because of
+	 * the backup copies (they are only needed in case of corruption).
+	 *
+	 * However, if we got here we have a journal problem too, so we
+	 * can't really start a transaction to mark the superblock.
+	 * Chicken out and just set the flag on the hope it will be written
+	 * to disk, and if not - we will simply wait until next fsck.
+	 */
+exit_err:
+	if (err) {
+		ext4_warning(sb, "can't update backup for group %u (err %d), "
+			     "forcing fsck on next reboot", group, err);
+		sbi->s_mount_state &= ~EXT4_VALID_FS;
+		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
+		mark_buffer_dirty(sbi->s_sbh);
+	}
+}
+
+/*
+ * ext4_add_new_descs() adds @count group descriptor of groups
+ * starting at @group
+ *
+ * @handle: journal handle
+ * @sb: super block
+ * @group: the group no. of the first group desc to be added
+ * @resize_inode: the resize inode
+ * @count: number of group descriptors to be added
+ */
+static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
+			      ext4_group_t group, struct inode *resize_inode,
+			      ext4_group_t count)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct buffer_head *gdb_bh;
+	int i, gdb_off, gdb_num, err = 0;
+	int meta_bg;
+
+	meta_bg = ext4_has_feature_meta_bg(sb);
+	for (i = 0; i < count; i++, group++) {
+		int reserved_gdb = ext4_bg_has_super(sb, group) ?
+			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
+
+		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
+		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+
+		/*
+		 * We will only either add reserved group blocks to a backup group
+		 * or remove reserved blocks for the first group in a new group block.
+		 * Doing both would be mean more complex code, and sane people don't
+		 * use non-sparse filesystems anymore.  This is already checked above.
+		 */
+		if (gdb_off) {
+			gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
+						     gdb_num);
+			BUFFER_TRACE(gdb_bh, "get_write_access");
+			err = ext4_journal_get_write_access(handle, gdb_bh);
+
+			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
+				err = reserve_backup_gdb(handle, resize_inode, group);
+		} else if (meta_bg != 0) {
+			err = add_new_gdb_meta_bg(sb, handle, group);
+		} else {
+			err = add_new_gdb(handle, resize_inode, group);
+		}
+		if (err)
+			break;
+	}
+	return err;
+}
+
+static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
+{
+	struct buffer_head *bh = sb_getblk(sb, block);
+	if (unlikely(!bh))
+		return NULL;
+	if (!bh_uptodate_or_lock(bh)) {
+		if (ext4_read_bh(bh, 0, NULL) < 0) {
+			brelse(bh);
+			return NULL;
+		}
+	}
+
+	return bh;
+}
+
+static int ext4_set_bitmap_checksums(struct super_block *sb,
+				     ext4_group_t group,
+				     struct ext4_group_desc *gdp,
+				     struct ext4_new_group_data *group_data)
+{
+	struct buffer_head *bh;
+
+	if (!ext4_has_metadata_csum(sb))
+		return 0;
+
+	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
+	if (!bh)
+		return -EIO;
+	ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
+				   EXT4_INODES_PER_GROUP(sb) / 8);
+	brelse(bh);
+
+	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
+	if (!bh)
+		return -EIO;
+	ext4_block_bitmap_csum_set(sb, group, gdp, bh);
+	brelse(bh);
+
+	return 0;
+}
+
+/*
+ * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
+ */
+static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
+				struct ext4_new_flex_group_data *flex_gd)
+{
+	struct ext4_new_group_data	*group_data = flex_gd->groups;
+	struct ext4_group_desc		*gdp;
+	struct ext4_sb_info		*sbi = EXT4_SB(sb);
+	struct buffer_head		*gdb_bh;
+	ext4_group_t			group;
+	__u16				*bg_flags = flex_gd->bg_flags;
+	int				i, gdb_off, gdb_num, err = 0;
+
+
+	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
+		group = group_data->group;
+
+		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
+		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+
+		/*
+		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
+		 */
+		gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
+		/* Update group descriptor block for new group */
+		gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
+						 gdb_off * EXT4_DESC_SIZE(sb));
+
+		memset(gdp, 0, EXT4_DESC_SIZE(sb));
+		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
+		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
+		err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
+		if (err) {
+			ext4_std_error(sb, err);
+			break;
+		}
+
+		ext4_inode_table_set(sb, gdp, group_data->inode_table);
+		ext4_free_group_clusters_set(sb, gdp,
+					     group_data->free_clusters_count);
+		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
+		if (ext4_has_group_desc_csum(sb))
+			ext4_itable_unused_set(sb, gdp,
+					       EXT4_INODES_PER_GROUP(sb));
+		gdp->bg_flags = cpu_to_le16(*bg_flags);
+		ext4_group_desc_csum_set(sb, group, gdp);
+
+		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
+		if (unlikely(err)) {
+			ext4_std_error(sb, err);
+			break;
+		}
+
+		/*
+		 * We can allocate memory for mb_alloc based on the new group
+		 * descriptor
+		 */
+		err = ext4_mb_add_groupinfo(sb, group, gdp);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+/*
+ * ext4_update_super() updates the super block so that the newly added
+ * groups can be seen by the filesystem.
+ *
+ * @sb: super block
+ * @flex_gd: new added groups
+ */
+static void ext4_update_super(struct super_block *sb,
+			     struct ext4_new_flex_group_data *flex_gd)
+{
+	ext4_fsblk_t blocks_count = 0;
+	ext4_fsblk_t free_blocks = 0;
+	ext4_fsblk_t reserved_blocks = 0;
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	int i;
+
+	BUG_ON(flex_gd->count == 0 || group_data == NULL);
+	/*
+	 * Make the new blocks and inodes valid next.  We do this before
+	 * increasing the group count so that once the group is enabled,
+	 * all of its blocks and inodes are already valid.
+	 *
+	 * We always allocate group-by-group, then block-by-block or
+	 * inode-by-inode within a group, so enabling these
+	 * blocks/inodes before the group is live won't actually let us
+	 * allocate the new space yet.
+	 */
+	for (i = 0; i < flex_gd->count; i++) {
+		blocks_count += group_data[i].blocks_count;
+		free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
+	}
+
+	reserved_blocks = ext4_r_blocks_count(es) * 100;
+	reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
+	reserved_blocks *= blocks_count;
+	do_div(reserved_blocks, 100);
+
+	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
+	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
+	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
+		     flex_gd->count);
+	le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
+		     flex_gd->count);
+
+	ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
+	/*
+	 * We need to protect s_groups_count against other CPUs seeing
+	 * inconsistent state in the superblock.
+	 *
+	 * The precise rules we use are:
+	 *
+	 * * Writers must perform a smp_wmb() after updating all
+	 *   dependent data and before modifying the groups count
+	 *
+	 * * Readers must perform an smp_rmb() after reading the groups
+	 *   count and before reading any dependent data.
+	 *
+	 * NB. These rules can be relaxed when checking the group count
+	 * while freeing data, as we can only allocate from a block
+	 * group after serialising against the group count, and we can
+	 * only then free after serialising in turn against that
+	 * allocation.
+	 */
+	smp_wmb();
+
+	/* Update the global fs size fields */
+	sbi->s_groups_count += flex_gd->count;
+	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
+			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
+
+	/* Update the reserved block counts only once the new group is
+	 * active. */
+	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
+				reserved_blocks);
+
+	/* Update the free space counts */
+	percpu_counter_add(&sbi->s_freeclusters_counter,
+			   EXT4_NUM_B2C(sbi, free_blocks));
+	percpu_counter_add(&sbi->s_freeinodes_counter,
+			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
+
+	ext4_debug("free blocks count %llu",
+		   percpu_counter_read(&sbi->s_freeclusters_counter));
+	if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group;
+		struct flex_groups *fg;
+
+		flex_group = ext4_flex_group(sbi, group_data[0].group);
+		fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
+		atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
+			     &fg->free_clusters);
+		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
+			   &fg->free_inodes);
+	}
+
+	/*
+	 * Update the fs overhead information
+	 */
+	ext4_calculate_overhead(sb);
+	es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT4-fs: added group %u:"
+		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
+		       blocks_count, free_blocks, reserved_blocks);
+}
+
+/* Add a flex group to an fs. Ensure we handle all possible error conditions
+ * _before_ we start modifying the filesystem, because we cannot abort the
+ * transaction and not have it write the data to disk.
+ */
+static int ext4_flex_group_add(struct super_block *sb,
+			       struct inode *resize_inode,
+			       struct ext4_new_flex_group_data *flex_gd)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	ext4_fsblk_t o_blocks_count;
+	ext4_grpblk_t last;
+	ext4_group_t group;
+	handle_t *handle;
+	unsigned reserved_gdb;
+	int err = 0, err2 = 0, credit;
+
+	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
+
+	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
+	o_blocks_count = ext4_blocks_count(es);
+	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
+	BUG_ON(last);
+
+	err = setup_new_flex_group_blocks(sb, flex_gd);
+	if (err)
+		goto exit;
+	/*
+	 * We will always be modifying at least the superblock and  GDT
+	 * blocks.  If we are adding a group past the last current GDT block,
+	 * we will also modify the inode and the dindirect block.  If we
+	 * are adding a group with superblock/GDT backups  we will also
+	 * modify each of the reserved GDT dindirect blocks.
+	 */
+	credit = 3;	/* sb, resize inode, resize inode dindirect */
+	/* GDT blocks */
+	credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
+	credit += reserved_gdb;	/* Reserved GDT dindirect blocks */
+	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		goto exit;
+	}
+
+	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+	if (err)
+		goto exit_journal;
+
+	group = flex_gd->groups[0].group;
+	BUG_ON(group != sbi->s_groups_count);
+	err = ext4_add_new_descs(handle, sb, group,
+				resize_inode, flex_gd->count);
+	if (err)
+		goto exit_journal;
+
+	err = ext4_setup_new_descs(handle, sb, flex_gd);
+	if (err)
+		goto exit_journal;
+
+	ext4_update_super(sb, flex_gd);
+
+	err = ext4_handle_dirty_super(handle, sb);
+
+exit_journal:
+	err2 = ext4_journal_stop(handle);
+	if (!err)
+		err = err2;
+
+	if (!err) {
+		int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+		int gdb_num_end = ((group + flex_gd->count - 1) /
+				   EXT4_DESC_PER_BLOCK(sb));
+		int meta_bg = ext4_has_feature_meta_bg(sb);
+		sector_t padding_blocks = meta_bg ? 0 : sbi->s_sbh->b_blocknr -
+					 ext4_group_first_block_no(sb, 0);
+		sector_t old_gdb = 0;
+
+		update_backups(sb, ext4_group_first_block_no(sb, 0),
+			       (char *)es, sizeof(struct ext4_super_block), 0);
+		for (; gdb_num <= gdb_num_end; gdb_num++) {
+			struct buffer_head *gdb_bh;
+
+			gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
+						     gdb_num);
+			if (old_gdb == gdb_bh->b_blocknr)
+				continue;
+			update_backups(sb, gdb_bh->b_blocknr - padding_blocks,
+				       gdb_bh->b_data, gdb_bh->b_size, meta_bg);
+			old_gdb = gdb_bh->b_blocknr;
+		}
+	}
+exit:
+	return err;
+}
+
+static int ext4_setup_next_flex_gd(struct super_block *sb,
+				    struct ext4_new_flex_group_data *flex_gd,
+				    ext4_fsblk_t n_blocks_count,
+				    unsigned long flexbg_size)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	ext4_fsblk_t o_blocks_count;
+	ext4_group_t n_group;
+	ext4_group_t group;
+	ext4_group_t last_group;
+	ext4_grpblk_t last;
+	ext4_grpblk_t clusters_per_group;
+	unsigned long i;
+
+	clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
+
+	o_blocks_count = ext4_blocks_count(es);
+
+	if (o_blocks_count == n_blocks_count)
+		return 0;
+
+	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
+	BUG_ON(last);
+	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
+
+	last_group = group | (flexbg_size - 1);
+	if (last_group > n_group)
+		last_group = n_group;
+
+	flex_gd->count = last_group - group + 1;
+
+	for (i = 0; i < flex_gd->count; i++) {
+		int overhead;
+
+		group_data[i].group = group + i;
+		group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
+		overhead = ext4_group_overhead_blocks(sb, group + i);
+		group_data[i].mdata_blocks = overhead;
+		group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
+		if (ext4_has_group_desc_csum(sb)) {
+			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
+					       EXT4_BG_INODE_UNINIT;
+			if (!test_opt(sb, INIT_INODE_TABLE))
+				flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
+		} else
+			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
+	}
+
+	if (last_group == n_group && ext4_has_group_desc_csum(sb))
+		/* We need to initialize block bitmap of last group. */
+		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
+
+	if ((last_group == n_group) && (last != clusters_per_group - 1)) {
+		group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
+		group_data[i - 1].free_clusters_count -= clusters_per_group -
+						       last - 1;
+	}
+
+	return 1;
+}
+
+/* Add group descriptor data to an existing or new group descriptor block.
+ * Ensure we handle all possible error conditions _before_ we start modifying
+ * the filesystem, because we cannot abort the transaction and not have it
+ * write the data to disk.
+ *
+ * If we are on a GDT block boundary, we need to get the reserved GDT block.
+ * Otherwise, we may need to add backup GDT blocks for a sparse group.
+ *
+ * We only need to hold the superblock lock while we are actually adding
+ * in the new group's counts to the superblock.  Prior to that we have
+ * not really "added" the group at all.  We re-check that we are still
+ * adding in the last group in case things have changed since verifying.
+ */
+int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
+{
+	struct ext4_new_flex_group_data flex_gd;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
+		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
+	struct inode *inode = NULL;
+	int gdb_off;
+	int err;
+	__u16 bg_flags = 0;
+
+	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
+
+	if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
+		ext4_warning(sb, "Can't resize non-sparse filesystem further");
+		return -EPERM;
+	}
+
+	if (ext4_blocks_count(es) + input->blocks_count <
+	    ext4_blocks_count(es)) {
+		ext4_warning(sb, "blocks_count overflow");
+		return -EINVAL;
+	}
+
+	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
+	    le32_to_cpu(es->s_inodes_count)) {
+		ext4_warning(sb, "inodes_count overflow");
+		return -EINVAL;
+	}
+
+	if (reserved_gdb || gdb_off == 0) {
+		if (!ext4_has_feature_resize_inode(sb) ||
+		    !le16_to_cpu(es->s_reserved_gdt_blocks)) {
+			ext4_warning(sb,
+				     "No reserved GDT blocks, can't resize");
+			return -EPERM;
+		}
+		inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
+		if (IS_ERR(inode)) {
+			ext4_warning(sb, "Error opening resize inode");
+			return PTR_ERR(inode);
+		}
+	}
+
+
+	err = verify_group_input(sb, input);
+	if (err)
+		goto out;
+
+	err = ext4_alloc_flex_bg_array(sb, input->group + 1);
+	if (err)
+		goto out;
+
+	err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
+	if (err)
+		goto out;
+
+	flex_gd.count = 1;
+	flex_gd.groups = input;
+	flex_gd.bg_flags = &bg_flags;
+	err = ext4_flex_group_add(sb, inode, &flex_gd);
+out:
+	iput(inode);
+	return err;
+} /* ext4_group_add */
+
+/*
+ * extend a group without checking assuming that checking has been done.
+ */
+static int ext4_group_extend_no_check(struct super_block *sb,
+				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	handle_t *handle;
+	int err = 0, err2;
+
+	/* We will update the superblock, one block bitmap, and
+	 * one group descriptor via ext4_group_add_blocks().
+	 */
+	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		ext4_warning(sb, "error %d on journal start", err);
+		return err;
+	}
+
+	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
+	if (err) {
+		ext4_warning(sb, "error %d on journal write access", err);
+		goto errout;
+	}
+
+	ext4_blocks_count_set(es, o_blocks_count + add);
+	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
+	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
+		   o_blocks_count + add);
+	/* We add the blocks to the bitmap and set the group need init bit */
+	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
+	if (err)
+		goto errout;
+	ext4_handle_dirty_super(handle, sb);
+	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
+		   o_blocks_count + add);
+errout:
+	err2 = ext4_journal_stop(handle);
+	if (err2 && !err)
+		err = err2;
+
+	if (!err) {
+		if (test_opt(sb, DEBUG))
+			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
+			       "blocks\n", ext4_blocks_count(es));
+		update_backups(sb, ext4_group_first_block_no(sb, 0),
+			       (char *)es, sizeof(struct ext4_super_block), 0);
+	}
+	return err;
+}
+
+/*
+ * Extend the filesystem to the new number of blocks specified.  This entry
+ * point is only used to extend the current filesystem to the end of the last
+ * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
+ * for emergencies (because it has no dependencies on reserved blocks).
+ *
+ * If we _really_ wanted, we could use default values to call ext4_group_add()
+ * allow the "remount" trick to work for arbitrary resizing, assuming enough
+ * GDT blocks are reserved to grow to the desired size.
+ */
+int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
+		      ext4_fsblk_t n_blocks_count)
+{
+	ext4_fsblk_t o_blocks_count;
+	ext4_grpblk_t last;
+	ext4_grpblk_t add;
+	struct buffer_head *bh;
+	int err;
+	ext4_group_t group;
+
+	o_blocks_count = ext4_blocks_count(es);
+
+	if (test_opt(sb, DEBUG))
+		ext4_msg(sb, KERN_DEBUG,
+			 "extending last group from %llu to %llu blocks",
+			 o_blocks_count, n_blocks_count);
+
+	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
+		return 0;
+
+	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
+		ext4_msg(sb, KERN_ERR,
+			 "filesystem too large to resize to %llu blocks safely",
+			 n_blocks_count);
+		return -EINVAL;
+	}
+
+	if (n_blocks_count < o_blocks_count) {
+		ext4_warning(sb, "can't shrink FS - resize aborted");
+		return -EINVAL;
+	}
+
+	/* Handle the remaining blocks in the last group only. */
+	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
+
+	if (last == 0) {
+		ext4_warning(sb, "need to use ext2online to resize further");
+		return -EPERM;
+	}
+
+	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
+
+	if (o_blocks_count + add < o_blocks_count) {
+		ext4_warning(sb, "blocks_count overflow");
+		return -EINVAL;
+	}
+
+	if (o_blocks_count + add > n_blocks_count)
+		add = n_blocks_count - o_blocks_count;
+
+	if (o_blocks_count + add < n_blocks_count)
+		ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
+			     o_blocks_count + add, add);
+
+	/* See if the device is actually as big as what was requested */
+	bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
+	if (IS_ERR(bh)) {
+		ext4_warning(sb, "can't read last block, resize aborted");
+		return -ENOSPC;
+	}
+	brelse(bh);
+
+	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
+	return err;
+} /* ext4_group_extend */
+
+
+static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
+{
+	return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
+}
+
+/*
+ * Release the resize inode and drop the resize_inode feature if there
+ * are no more reserved gdt blocks, and then convert the file system
+ * to enable meta_bg
+ */
+static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
+{
+	handle_t *handle;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	ext4_fsblk_t nr;
+	int i, ret, err = 0;
+	int credits = 1;
+
+	ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
+	if (inode) {
+		if (es->s_reserved_gdt_blocks) {
+			ext4_error(sb, "Unexpected non-zero "
+				   "s_reserved_gdt_blocks");
+			return -EPERM;
+		}
+
+		/* Do a quick sanity check of the resize inode */
+		if (inode->i_blocks != 1 << (inode->i_blkbits -
+					     (9 - sbi->s_cluster_bits)))
+			goto invalid_resize_inode;
+		for (i = 0; i < EXT4_N_BLOCKS; i++) {
+			if (i == EXT4_DIND_BLOCK) {
+				if (ei->i_data[i])
+					continue;
+				else
+					goto invalid_resize_inode;
+			}
+			if (ei->i_data[i])
+				goto invalid_resize_inode;
+		}
+		credits += 3;	/* block bitmap, bg descriptor, resize inode */
+	}
+
+	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+	if (err)
+		goto errout;
+
+	ext4_clear_feature_resize_inode(sb);
+	ext4_set_feature_meta_bg(sb);
+	sbi->s_es->s_first_meta_bg =
+		cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
+
+	err = ext4_handle_dirty_super(handle, sb);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto errout;
+	}
+
+	if (inode) {
+		nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
+		ext4_free_blocks(handle, inode, NULL, nr, 1,
+				 EXT4_FREE_BLOCKS_METADATA |
+				 EXT4_FREE_BLOCKS_FORGET);
+		ei->i_data[EXT4_DIND_BLOCK] = 0;
+		inode->i_blocks = 0;
+
+		err = ext4_mark_inode_dirty(handle, inode);
+		if (err)
+			ext4_std_error(sb, err);
+	}
+
+errout:
+	ret = ext4_journal_stop(handle);
+	return err ? err : ret;
+
+invalid_resize_inode:
+	ext4_error(sb, "corrupted/inconsistent resize inode");
+	return -EINVAL;
+}
+
+/*
+ * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
+ *
+ * @sb: super block of the fs to be resized
+ * @n_blocks_count: the number of blocks resides in the resized fs
+ */
+int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
+{
+	struct ext4_new_flex_group_data *flex_gd = NULL;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct buffer_head *bh;
+	struct inode *resize_inode = NULL;
+	ext4_grpblk_t add, offset;
+	unsigned long n_desc_blocks;
+	unsigned long o_desc_blocks;
+	ext4_group_t o_group;
+	ext4_group_t n_group;
+	ext4_fsblk_t o_blocks_count;
+	ext4_fsblk_t n_blocks_count_retry = 0;
+	unsigned long last_update_time = 0;
+	int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
+	int meta_bg;
+
+	/* See if the device is actually as big as what was requested */
+	bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
+	if (IS_ERR(bh)) {
+		ext4_warning(sb, "can't read last block, resize aborted");
+		return -ENOSPC;
+	}
+	brelse(bh);
+
+	/*
+	 * For bigalloc, trim the requested size to the nearest cluster
+	 * boundary to avoid creating an unusable filesystem. We do this
+	 * silently, instead of returning an error, to avoid breaking
+	 * callers that blindly resize the filesystem to the full size of
+	 * the underlying block device.
+	 */
+	if (ext4_has_feature_bigalloc(sb))
+		n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
+
+retry:
+	o_blocks_count = ext4_blocks_count(es);
+
+	ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
+		 "to %llu blocks", o_blocks_count, n_blocks_count);
+
+	if (n_blocks_count < o_blocks_count) {
+		/* On-line shrinking not supported */
+		ext4_warning(sb, "can't shrink FS - resize aborted");
+		return -EINVAL;
+	}
+
+	if (n_blocks_count == o_blocks_count)
+		/* Nothing need to do */
+		return 0;
+
+	n_group = ext4_get_group_number(sb, n_blocks_count - 1);
+	if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
+		ext4_warning(sb, "resize would cause inodes_count overflow");
+		return -EINVAL;
+	}
+	ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
+
+	n_desc_blocks = num_desc_blocks(sb, n_group + 1);
+	o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
+
+	meta_bg = ext4_has_feature_meta_bg(sb);
+
+	if (ext4_has_feature_resize_inode(sb)) {
+		if (meta_bg) {
+			ext4_error(sb, "resize_inode and meta_bg enabled "
+				   "simultaneously");
+			return -EINVAL;
+		}
+		if (n_desc_blocks > o_desc_blocks +
+		    le16_to_cpu(es->s_reserved_gdt_blocks)) {
+			n_blocks_count_retry = n_blocks_count;
+			n_desc_blocks = o_desc_blocks +
+				le16_to_cpu(es->s_reserved_gdt_blocks);
+			n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
+			n_blocks_count = (ext4_fsblk_t)n_group *
+				EXT4_BLOCKS_PER_GROUP(sb) +
+				le32_to_cpu(es->s_first_data_block);
+			n_group--; /* set to last group number */
+		}
+
+		if (!resize_inode)
+			resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
+						 EXT4_IGET_SPECIAL);
+		if (IS_ERR(resize_inode)) {
+			ext4_warning(sb, "Error opening resize inode");
+			return PTR_ERR(resize_inode);
+		}
+	}
+
+	if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
+		err = ext4_convert_meta_bg(sb, resize_inode);
+		if (err)
+			goto out;
+		if (resize_inode) {
+			iput(resize_inode);
+			resize_inode = NULL;
+		}
+		if (n_blocks_count_retry) {
+			n_blocks_count = n_blocks_count_retry;
+			n_blocks_count_retry = 0;
+			goto retry;
+		}
+	}
+
+	/*
+	 * Make sure the last group has enough space so that it's
+	 * guaranteed to have enough space for all metadata blocks
+	 * that it might need to hold.  (We might not need to store
+	 * the inode table blocks in the last block group, but there
+	 * will be cases where this might be needed.)
+	 */
+	if ((ext4_group_first_block_no(sb, n_group) +
+	     ext4_group_overhead_blocks(sb, n_group) + 2 +
+	     sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
+		n_blocks_count = ext4_group_first_block_no(sb, n_group);
+		n_group--;
+		n_blocks_count_retry = 0;
+		if (resize_inode) {
+			iput(resize_inode);
+			resize_inode = NULL;
+		}
+		goto retry;
+	}
+
+	/* extend the last group */
+	if (n_group == o_group)
+		add = n_blocks_count - o_blocks_count;
+	else
+		add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
+	if (add > 0) {
+		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
+		if (err)
+			goto out;
+	}
+
+	if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
+		goto out;
+
+	err = ext4_alloc_flex_bg_array(sb, n_group + 1);
+	if (err)
+		goto out;
+
+	err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
+	if (err)
+		goto out;
+
+	flex_gd = alloc_flex_gd(flexbg_size);
+	if (flex_gd == NULL) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/* Add flex groups. Note that a regular group is a
+	 * flex group with 1 group.
+	 */
+	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
+					      flexbg_size)) {
+		if (jiffies - last_update_time > HZ * 10) {
+			if (last_update_time)
+				ext4_msg(sb, KERN_INFO,
+					 "resized to %llu blocks",
+					 ext4_blocks_count(es));
+			last_update_time = jiffies;
+		}
+		if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
+			break;
+		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
+		if (unlikely(err))
+			break;
+	}
+
+	if (!err && n_blocks_count_retry) {
+		n_blocks_count = n_blocks_count_retry;
+		n_blocks_count_retry = 0;
+		free_flex_gd(flex_gd);
+		flex_gd = NULL;
+		if (resize_inode) {
+			iput(resize_inode);
+			resize_inode = NULL;
+		}
+		goto retry;
+	}
+
+out:
+	if (flex_gd)
+		free_flex_gd(flex_gd);
+	if (resize_inode != NULL)
+		iput(resize_inode);
+	if (err)
+		ext4_warning(sb, "error (%d) occurred during "
+			     "file system resize", err);
+	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
+		 ext4_blocks_count(es));
+	return err;
+}
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
new file mode 100644
index 000000000..e386d67cf
--- /dev/null
+++ b/fs/ext4/super.c
@@ -0,0 +1,6811 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/super.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/parser.h>
+#include <linux/buffer_head.h>
+#include <linux/exportfs.h>
+#include <linux/vfs.h>
+#include <linux/random.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/quotaops.h>
+#include <linux/seq_file.h>
+#include <linux/ctype.h>
+#include <linux/log2.h>
+#include <linux/crc16.h>
+#include <linux/dax.h>
+#include <linux/cleancache.h>
+#include <linux/uaccess.h>
+#include <linux/iversion.h>
+#include <linux/unicode.h>
+#include <linux/part_stat.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+
+#include "ext4.h"
+#include "ext4_extents.h"	/* Needed for trace points definition */
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "mballoc.h"
+#include "fsmap.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/ext4.h>
+
+static struct ext4_lazy_init *ext4_li_info;
+static struct mutex ext4_li_mtx;
+static struct ratelimit_state ext4_mount_msg_ratelimit;
+
+static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
+			     unsigned long journal_devnum);
+static int ext4_show_options(struct seq_file *seq, struct dentry *root);
+static int ext4_commit_super(struct super_block *sb, int sync);
+static int ext4_mark_recovery_complete(struct super_block *sb,
+					struct ext4_super_block *es);
+static int ext4_clear_journal_err(struct super_block *sb,
+				  struct ext4_super_block *es);
+static int ext4_sync_fs(struct super_block *sb, int wait);
+static int ext4_remount(struct super_block *sb, int *flags, char *data);
+static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
+static int ext4_unfreeze(struct super_block *sb);
+static int ext4_freeze(struct super_block *sb);
+static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
+		       const char *dev_name, void *data);
+static inline int ext2_feature_set_ok(struct super_block *sb);
+static inline int ext3_feature_set_ok(struct super_block *sb);
+static int ext4_feature_set_ok(struct super_block *sb, int readonly);
+static void ext4_destroy_lazyinit_thread(void);
+static void ext4_unregister_li_request(struct super_block *sb);
+static void ext4_clear_request_list(void);
+static struct inode *ext4_get_journal_inode(struct super_block *sb,
+					    unsigned int journal_inum);
+
+/*
+ * Lock ordering
+ *
+ * Note the difference between i_mmap_sem (EXT4_I(inode)->i_mmap_sem) and
+ * i_mmap_rwsem (inode->i_mmap_rwsem)!
+ *
+ * page fault path:
+ * mmap_lock -> sb_start_pagefault -> i_mmap_sem (r) -> transaction start ->
+ *   page lock -> i_data_sem (rw)
+ *
+ * buffered write path:
+ * sb_start_write -> i_mutex -> mmap_lock
+ * sb_start_write -> i_mutex -> transaction start -> page lock ->
+ *   i_data_sem (rw)
+ *
+ * truncate:
+ * sb_start_write -> i_mutex -> i_mmap_sem (w) -> i_mmap_rwsem (w) -> page lock
+ * sb_start_write -> i_mutex -> i_mmap_sem (w) -> transaction start ->
+ *   i_data_sem (rw)
+ *
+ * direct IO:
+ * sb_start_write -> i_mutex -> mmap_lock
+ * sb_start_write -> i_mutex -> transaction start -> i_data_sem (rw)
+ *
+ * writepages:
+ * transaction start -> page lock(s) -> i_data_sem (rw)
+ */
+
+#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
+static struct file_system_type ext2_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ext2",
+	.mount		= ext4_mount,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("ext2");
+MODULE_ALIAS("ext2");
+#define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
+#else
+#define IS_EXT2_SB(sb) (0)
+#endif
+
+
+static struct file_system_type ext3_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ext3",
+	.mount		= ext4_mount,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("ext3");
+MODULE_ALIAS("ext3");
+#define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
+
+
+static inline void __ext4_read_bh(struct buffer_head *bh, int op_flags,
+				  bh_end_io_t *end_io)
+{
+	/*
+	 * buffer's verified bit is no longer valid after reading from
+	 * disk again due to write out error, clear it to make sure we
+	 * recheck the buffer contents.
+	 */
+	clear_buffer_verified(bh);
+
+	bh->b_end_io = end_io ? end_io : end_buffer_read_sync;
+	get_bh(bh);
+	submit_bh(REQ_OP_READ, op_flags, bh);
+}
+
+void ext4_read_bh_nowait(struct buffer_head *bh, int op_flags,
+			 bh_end_io_t *end_io)
+{
+	BUG_ON(!buffer_locked(bh));
+
+	if (ext4_buffer_uptodate(bh)) {
+		unlock_buffer(bh);
+		return;
+	}
+	__ext4_read_bh(bh, op_flags, end_io);
+}
+
+int ext4_read_bh(struct buffer_head *bh, int op_flags, bh_end_io_t *end_io)
+{
+	BUG_ON(!buffer_locked(bh));
+
+	if (ext4_buffer_uptodate(bh)) {
+		unlock_buffer(bh);
+		return 0;
+	}
+
+	__ext4_read_bh(bh, op_flags, end_io);
+
+	wait_on_buffer(bh);
+	if (buffer_uptodate(bh))
+		return 0;
+	return -EIO;
+}
+
+int ext4_read_bh_lock(struct buffer_head *bh, int op_flags, bool wait)
+{
+	lock_buffer(bh);
+	if (!wait) {
+		ext4_read_bh_nowait(bh, op_flags, NULL);
+		return 0;
+	}
+	return ext4_read_bh(bh, op_flags, NULL);
+}
+
+/*
+ * This works like __bread_gfp() except it uses ERR_PTR for error
+ * returns.  Currently with sb_bread it's impossible to distinguish
+ * between ENOMEM and EIO situations (since both result in a NULL
+ * return.
+ */
+static struct buffer_head *__ext4_sb_bread_gfp(struct super_block *sb,
+					       sector_t block, int op_flags,
+					       gfp_t gfp)
+{
+	struct buffer_head *bh;
+	int ret;
+
+	bh = sb_getblk_gfp(sb, block, gfp);
+	if (bh == NULL)
+		return ERR_PTR(-ENOMEM);
+	if (ext4_buffer_uptodate(bh))
+		return bh;
+
+	ret = ext4_read_bh_lock(bh, REQ_META | op_flags, true);
+	if (ret) {
+		put_bh(bh);
+		return ERR_PTR(ret);
+	}
+	return bh;
+}
+
+struct buffer_head *ext4_sb_bread(struct super_block *sb, sector_t block,
+				   int op_flags)
+{
+	return __ext4_sb_bread_gfp(sb, block, op_flags, __GFP_MOVABLE);
+}
+
+struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,
+					    sector_t block)
+{
+	return __ext4_sb_bread_gfp(sb, block, 0, 0);
+}
+
+void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block)
+{
+	struct buffer_head *bh = sb_getblk_gfp(sb, block, 0);
+
+	if (likely(bh)) {
+		if (trylock_buffer(bh))
+			ext4_read_bh_nowait(bh, REQ_RAHEAD, NULL);
+		brelse(bh);
+	}
+}
+
+static int ext4_verify_csum_type(struct super_block *sb,
+				 struct ext4_super_block *es)
+{
+	if (!ext4_has_feature_metadata_csum(sb))
+		return 1;
+
+	return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
+}
+
+static __le32 ext4_superblock_csum(struct super_block *sb,
+				   struct ext4_super_block *es)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int offset = offsetof(struct ext4_super_block, s_checksum);
+	__u32 csum;
+
+	csum = ext4_chksum(sbi, ~0, (char *)es, offset);
+
+	return cpu_to_le32(csum);
+}
+
+static int ext4_superblock_csum_verify(struct super_block *sb,
+				       struct ext4_super_block *es)
+{
+	if (!ext4_has_metadata_csum(sb))
+		return 1;
+
+	return es->s_checksum == ext4_superblock_csum(sb, es);
+}
+
+void ext4_superblock_csum_set(struct super_block *sb)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	if (!ext4_has_metadata_csum(sb))
+		return;
+
+	es->s_checksum = ext4_superblock_csum(sb, es);
+}
+
+ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
+			       struct ext4_group_desc *bg)
+{
+	return le32_to_cpu(bg->bg_block_bitmap_lo) |
+		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
+		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
+}
+
+ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
+			       struct ext4_group_desc *bg)
+{
+	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
+		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
+		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
+}
+
+ext4_fsblk_t ext4_inode_table(struct super_block *sb,
+			      struct ext4_group_desc *bg)
+{
+	return le32_to_cpu(bg->bg_inode_table_lo) |
+		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
+		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
+}
+
+__u32 ext4_free_group_clusters(struct super_block *sb,
+			       struct ext4_group_desc *bg)
+{
+	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
+		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
+		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
+}
+
+__u32 ext4_free_inodes_count(struct super_block *sb,
+			      struct ext4_group_desc *bg)
+{
+	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
+		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
+		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
+}
+
+__u32 ext4_used_dirs_count(struct super_block *sb,
+			      struct ext4_group_desc *bg)
+{
+	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
+		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
+		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
+}
+
+__u32 ext4_itable_unused_count(struct super_block *sb,
+			      struct ext4_group_desc *bg)
+{
+	return le16_to_cpu(bg->bg_itable_unused_lo) |
+		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
+		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
+}
+
+void ext4_block_bitmap_set(struct super_block *sb,
+			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
+{
+	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
+	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
+		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
+}
+
+void ext4_inode_bitmap_set(struct super_block *sb,
+			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
+{
+	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
+	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
+		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
+}
+
+void ext4_inode_table_set(struct super_block *sb,
+			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
+{
+	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
+	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
+		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
+}
+
+void ext4_free_group_clusters_set(struct super_block *sb,
+				  struct ext4_group_desc *bg, __u32 count)
+{
+	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
+	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
+		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
+}
+
+void ext4_free_inodes_set(struct super_block *sb,
+			  struct ext4_group_desc *bg, __u32 count)
+{
+	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
+	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
+		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
+}
+
+void ext4_used_dirs_set(struct super_block *sb,
+			  struct ext4_group_desc *bg, __u32 count)
+{
+	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
+	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
+		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
+}
+
+void ext4_itable_unused_set(struct super_block *sb,
+			  struct ext4_group_desc *bg, __u32 count)
+{
+	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
+	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
+		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
+}
+
+static void __ext4_update_tstamp(__le32 *lo, __u8 *hi)
+{
+	time64_t now = ktime_get_real_seconds();
+
+	now = clamp_val(now, 0, (1ull << 40) - 1);
+
+	*lo = cpu_to_le32(lower_32_bits(now));
+	*hi = upper_32_bits(now);
+}
+
+static time64_t __ext4_get_tstamp(__le32 *lo, __u8 *hi)
+{
+	return ((time64_t)(*hi) << 32) + le32_to_cpu(*lo);
+}
+#define ext4_update_tstamp(es, tstamp) \
+	__ext4_update_tstamp(&(es)->tstamp, &(es)->tstamp ## _hi)
+#define ext4_get_tstamp(es, tstamp) \
+	__ext4_get_tstamp(&(es)->tstamp, &(es)->tstamp ## _hi)
+
+/*
+ * The del_gendisk() function uninitializes the disk-specific data
+ * structures, including the bdi structure, without telling anyone
+ * else.  Once this happens, any attempt to call mark_buffer_dirty()
+ * (for example, by ext4_commit_super), will cause a kernel OOPS.
+ * This is a kludge to prevent these oops until we can put in a proper
+ * hook in del_gendisk() to inform the VFS and file system layers.
+ */
+static int block_device_ejected(struct super_block *sb)
+{
+	struct inode *bd_inode = sb->s_bdev->bd_inode;
+	struct backing_dev_info *bdi = inode_to_bdi(bd_inode);
+
+	return bdi->dev == NULL;
+}
+
+static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
+{
+	struct super_block		*sb = journal->j_private;
+	struct ext4_sb_info		*sbi = EXT4_SB(sb);
+	int				error = is_journal_aborted(journal);
+	struct ext4_journal_cb_entry	*jce;
+
+	BUG_ON(txn->t_state == T_FINISHED);
+
+	ext4_process_freed_data(sb, txn->t_tid);
+
+	spin_lock(&sbi->s_md_lock);
+	while (!list_empty(&txn->t_private_list)) {
+		jce = list_entry(txn->t_private_list.next,
+				 struct ext4_journal_cb_entry, jce_list);
+		list_del_init(&jce->jce_list);
+		spin_unlock(&sbi->s_md_lock);
+		jce->jce_func(sb, jce, error);
+		spin_lock(&sbi->s_md_lock);
+	}
+	spin_unlock(&sbi->s_md_lock);
+}
+
+/*
+ * This writepage callback for write_cache_pages()
+ * takes care of a few cases after page cleaning.
+ *
+ * write_cache_pages() already checks for dirty pages
+ * and calls clear_page_dirty_for_io(), which we want,
+ * to write protect the pages.
+ *
+ * However, we may have to redirty a page (see below.)
+ */
+static int ext4_journalled_writepage_callback(struct page *page,
+					      struct writeback_control *wbc,
+					      void *data)
+{
+	transaction_t *transaction = (transaction_t *) data;
+	struct buffer_head *bh, *head;
+	struct journal_head *jh;
+
+	bh = head = page_buffers(page);
+	do {
+		/*
+		 * We have to redirty a page in these cases:
+		 * 1) If buffer is dirty, it means the page was dirty because it
+		 * contains a buffer that needs checkpointing. So the dirty bit
+		 * needs to be preserved so that checkpointing writes the buffer
+		 * properly.
+		 * 2) If buffer is not part of the committing transaction
+		 * (we may have just accidentally come across this buffer because
+		 * inode range tracking is not exact) or if the currently running
+		 * transaction already contains this buffer as well, dirty bit
+		 * needs to be preserved so that the buffer gets writeprotected
+		 * properly on running transaction's commit.
+		 */
+		jh = bh2jh(bh);
+		if (buffer_dirty(bh) ||
+		    (jh && (jh->b_transaction != transaction ||
+			    jh->b_next_transaction))) {
+			redirty_page_for_writepage(wbc, page);
+			goto out;
+		}
+	} while ((bh = bh->b_this_page) != head);
+
+out:
+	return AOP_WRITEPAGE_ACTIVATE;
+}
+
+static int ext4_journalled_submit_inode_data_buffers(struct jbd2_inode *jinode)
+{
+	struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
+	struct writeback_control wbc = {
+		.sync_mode =  WB_SYNC_ALL,
+		.nr_to_write = LONG_MAX,
+		.range_start = jinode->i_dirty_start,
+		.range_end = jinode->i_dirty_end,
+        };
+
+	return write_cache_pages(mapping, &wbc,
+				 ext4_journalled_writepage_callback,
+				 jinode->i_transaction);
+}
+
+static int ext4_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
+{
+	int ret;
+
+	if (ext4_should_journal_data(jinode->i_vfs_inode))
+		ret = ext4_journalled_submit_inode_data_buffers(jinode);
+	else
+		ret = jbd2_journal_submit_inode_data_buffers(jinode);
+
+	return ret;
+}
+
+static int ext4_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
+{
+	int ret = 0;
+
+	if (!ext4_should_journal_data(jinode->i_vfs_inode))
+		ret = jbd2_journal_finish_inode_data_buffers(jinode);
+
+	return ret;
+}
+
+static bool system_going_down(void)
+{
+	return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
+		|| system_state == SYSTEM_RESTART;
+}
+
+struct ext4_err_translation {
+	int code;
+	int errno;
+};
+
+#define EXT4_ERR_TRANSLATE(err) { .code = EXT4_ERR_##err, .errno = err }
+
+static struct ext4_err_translation err_translation[] = {
+	EXT4_ERR_TRANSLATE(EIO),
+	EXT4_ERR_TRANSLATE(ENOMEM),
+	EXT4_ERR_TRANSLATE(EFSBADCRC),
+	EXT4_ERR_TRANSLATE(EFSCORRUPTED),
+	EXT4_ERR_TRANSLATE(ENOSPC),
+	EXT4_ERR_TRANSLATE(ENOKEY),
+	EXT4_ERR_TRANSLATE(EROFS),
+	EXT4_ERR_TRANSLATE(EFBIG),
+	EXT4_ERR_TRANSLATE(EEXIST),
+	EXT4_ERR_TRANSLATE(ERANGE),
+	EXT4_ERR_TRANSLATE(EOVERFLOW),
+	EXT4_ERR_TRANSLATE(EBUSY),
+	EXT4_ERR_TRANSLATE(ENOTDIR),
+	EXT4_ERR_TRANSLATE(ENOTEMPTY),
+	EXT4_ERR_TRANSLATE(ESHUTDOWN),
+	EXT4_ERR_TRANSLATE(EFAULT),
+};
+
+static int ext4_errno_to_code(int errno)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(err_translation); i++)
+		if (err_translation[i].errno == errno)
+			return err_translation[i].code;
+	return EXT4_ERR_UNKNOWN;
+}
+
+static void __save_error_info(struct super_block *sb, int error,
+			      __u32 ino, __u64 block,
+			      const char *func, unsigned int line)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
+	if (bdev_read_only(sb->s_bdev))
+		return;
+	/* We default to EFSCORRUPTED error... */
+	if (error == 0)
+		error = EFSCORRUPTED;
+	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
+	ext4_update_tstamp(es, s_last_error_time);
+	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
+	es->s_last_error_line = cpu_to_le32(line);
+	es->s_last_error_ino = cpu_to_le32(ino);
+	es->s_last_error_block = cpu_to_le64(block);
+	es->s_last_error_errcode = ext4_errno_to_code(error);
+	if (!es->s_first_error_time) {
+		es->s_first_error_time = es->s_last_error_time;
+		es->s_first_error_time_hi = es->s_last_error_time_hi;
+		strncpy(es->s_first_error_func, func,
+			sizeof(es->s_first_error_func));
+		es->s_first_error_line = cpu_to_le32(line);
+		es->s_first_error_ino = es->s_last_error_ino;
+		es->s_first_error_block = es->s_last_error_block;
+		es->s_first_error_errcode = es->s_last_error_errcode;
+	}
+	/*
+	 * Start the daily error reporting function if it hasn't been
+	 * started already
+	 */
+	if (!es->s_error_count)
+		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
+	le32_add_cpu(&es->s_error_count, 1);
+}
+
+static void save_error_info(struct super_block *sb, int error,
+			    __u32 ino, __u64 block,
+			    const char *func, unsigned int line)
+{
+	__save_error_info(sb, error, ino, block, func, line);
+	if (!bdev_read_only(sb->s_bdev))
+		ext4_commit_super(sb, 1);
+}
+
+/* Deal with the reporting of failure conditions on a filesystem such as
+ * inconsistencies detected or read IO failures.
+ *
+ * On ext2, we can store the error state of the filesystem in the
+ * superblock.  That is not possible on ext4, because we may have other
+ * write ordering constraints on the superblock which prevent us from
+ * writing it out straight away; and given that the journal is about to
+ * be aborted, we can't rely on the current, or future, transactions to
+ * write out the superblock safely.
+ *
+ * We'll just use the jbd2_journal_abort() error code to record an error in
+ * the journal instead.  On recovery, the journal will complain about
+ * that error until we've noted it down and cleared it.
+ */
+
+static void ext4_handle_error(struct super_block *sb)
+{
+	journal_t *journal = EXT4_SB(sb)->s_journal;
+
+	if (test_opt(sb, WARN_ON_ERROR))
+		WARN_ON_ONCE(1);
+
+	if (sb_rdonly(sb) || test_opt(sb, ERRORS_CONT))
+		return;
+
+	ext4_set_mount_flag(sb, EXT4_MF_FS_ABORTED);
+	if (journal)
+		jbd2_journal_abort(journal, -EIO);
+	/*
+	 * We force ERRORS_RO behavior when system is rebooting. Otherwise we
+	 * could panic during 'reboot -f' as the underlying device got already
+	 * disabled.
+	 */
+	if (test_opt(sb, ERRORS_RO) || system_going_down()) {
+		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
+		/*
+		 * Make sure updated value of ->s_mount_flags will be visible
+		 * before ->s_flags update
+		 */
+		smp_wmb();
+		sb->s_flags |= SB_RDONLY;
+	} else if (test_opt(sb, ERRORS_PANIC)) {
+		panic("EXT4-fs (device %s): panic forced after error\n",
+			sb->s_id);
+	}
+}
+
+#define ext4_error_ratelimit(sb)					\
+		___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state),	\
+			     "EXT4-fs error")
+
+void __ext4_error(struct super_block *sb, const char *function,
+		  unsigned int line, int error, __u64 block,
+		  const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
+		return;
+
+	trace_ext4_error(sb, function, line);
+	if (ext4_error_ratelimit(sb)) {
+		va_start(args, fmt);
+		vaf.fmt = fmt;
+		vaf.va = &args;
+		printk(KERN_CRIT
+		       "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
+		       sb->s_id, function, line, current->comm, &vaf);
+		va_end(args);
+	}
+	save_error_info(sb, error, 0, block, function, line);
+	ext4_handle_error(sb);
+}
+
+void __ext4_error_inode(struct inode *inode, const char *function,
+			unsigned int line, ext4_fsblk_t block, int error,
+			const char *fmt, ...)
+{
+	va_list args;
+	struct va_format vaf;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return;
+
+	trace_ext4_error(inode->i_sb, function, line);
+	if (ext4_error_ratelimit(inode->i_sb)) {
+		va_start(args, fmt);
+		vaf.fmt = fmt;
+		vaf.va = &args;
+		if (block)
+			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
+			       "inode #%lu: block %llu: comm %s: %pV\n",
+			       inode->i_sb->s_id, function, line, inode->i_ino,
+			       block, current->comm, &vaf);
+		else
+			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
+			       "inode #%lu: comm %s: %pV\n",
+			       inode->i_sb->s_id, function, line, inode->i_ino,
+			       current->comm, &vaf);
+		va_end(args);
+	}
+	save_error_info(inode->i_sb, error, inode->i_ino, block,
+			function, line);
+	ext4_handle_error(inode->i_sb);
+}
+
+void __ext4_error_file(struct file *file, const char *function,
+		       unsigned int line, ext4_fsblk_t block,
+		       const char *fmt, ...)
+{
+	va_list args;
+	struct va_format vaf;
+	struct inode *inode = file_inode(file);
+	char pathname[80], *path;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return;
+
+	trace_ext4_error(inode->i_sb, function, line);
+	if (ext4_error_ratelimit(inode->i_sb)) {
+		path = file_path(file, pathname, sizeof(pathname));
+		if (IS_ERR(path))
+			path = "(unknown)";
+		va_start(args, fmt);
+		vaf.fmt = fmt;
+		vaf.va = &args;
+		if (block)
+			printk(KERN_CRIT
+			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
+			       "block %llu: comm %s: path %s: %pV\n",
+			       inode->i_sb->s_id, function, line, inode->i_ino,
+			       block, current->comm, path, &vaf);
+		else
+			printk(KERN_CRIT
+			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
+			       "comm %s: path %s: %pV\n",
+			       inode->i_sb->s_id, function, line, inode->i_ino,
+			       current->comm, path, &vaf);
+		va_end(args);
+	}
+	save_error_info(inode->i_sb, EFSCORRUPTED, inode->i_ino, block,
+			function, line);
+	ext4_handle_error(inode->i_sb);
+}
+
+const char *ext4_decode_error(struct super_block *sb, int errno,
+			      char nbuf[16])
+{
+	char *errstr = NULL;
+
+	switch (errno) {
+	case -EFSCORRUPTED:
+		errstr = "Corrupt filesystem";
+		break;
+	case -EFSBADCRC:
+		errstr = "Filesystem failed CRC";
+		break;
+	case -EIO:
+		errstr = "IO failure";
+		break;
+	case -ENOMEM:
+		errstr = "Out of memory";
+		break;
+	case -EROFS:
+		if (!sb || (EXT4_SB(sb)->s_journal &&
+			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
+			errstr = "Journal has aborted";
+		else
+			errstr = "Readonly filesystem";
+		break;
+	default:
+		/* If the caller passed in an extra buffer for unknown
+		 * errors, textualise them now.  Else we just return
+		 * NULL. */
+		if (nbuf) {
+			/* Check for truncated error codes... */
+			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
+				errstr = nbuf;
+		}
+		break;
+	}
+
+	return errstr;
+}
+
+/* __ext4_std_error decodes expected errors from journaling functions
+ * automatically and invokes the appropriate error response.  */
+
+void __ext4_std_error(struct super_block *sb, const char *function,
+		      unsigned int line, int errno)
+{
+	char nbuf[16];
+	const char *errstr;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
+		return;
+
+	/* Special case: if the error is EROFS, and we're not already
+	 * inside a transaction, then there's really no point in logging
+	 * an error. */
+	if (errno == -EROFS && journal_current_handle() == NULL && sb_rdonly(sb))
+		return;
+
+	if (ext4_error_ratelimit(sb)) {
+		errstr = ext4_decode_error(sb, errno, nbuf);
+		printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
+		       sb->s_id, function, line, errstr);
+	}
+
+	save_error_info(sb, -errno, 0, 0, function, line);
+	ext4_handle_error(sb);
+}
+
+/*
+ * ext4_abort is a much stronger failure handler than ext4_error.  The
+ * abort function may be used to deal with unrecoverable failures such
+ * as journal IO errors or ENOMEM at a critical moment in log management.
+ *
+ * We unconditionally force the filesystem into an ABORT|READONLY state,
+ * unless the error response on the fs has been set to panic in which
+ * case we take the easy way out and panic immediately.
+ */
+
+void __ext4_abort(struct super_block *sb, const char *function,
+		  unsigned int line, int error, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
+		return;
+
+	save_error_info(sb, error, 0, 0, function, line);
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: %pV\n",
+	       sb->s_id, function, line, &vaf);
+	va_end(args);
+
+	if (sb_rdonly(sb) == 0) {
+		ext4_set_mount_flag(sb, EXT4_MF_FS_ABORTED);
+		if (EXT4_SB(sb)->s_journal)
+			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
+
+		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
+		/*
+		 * Make sure updated value of ->s_mount_flags will be visible
+		 * before ->s_flags update
+		 */
+		smp_wmb();
+		sb->s_flags |= SB_RDONLY;
+	}
+	if (test_opt(sb, ERRORS_PANIC) && !system_going_down())
+		panic("EXT4-fs panic from previous error\n");
+}
+
+void __ext4_msg(struct super_block *sb,
+		const char *prefix, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	atomic_inc(&EXT4_SB(sb)->s_msg_count);
+	if (!___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state), "EXT4-fs"))
+		return;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
+	va_end(args);
+}
+
+static int ext4_warning_ratelimit(struct super_block *sb)
+{
+	atomic_inc(&EXT4_SB(sb)->s_warning_count);
+	return ___ratelimit(&(EXT4_SB(sb)->s_warning_ratelimit_state),
+			    "EXT4-fs warning");
+}
+
+void __ext4_warning(struct super_block *sb, const char *function,
+		    unsigned int line, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	if (!ext4_warning_ratelimit(sb))
+		return;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
+	       sb->s_id, function, line, &vaf);
+	va_end(args);
+}
+
+void __ext4_warning_inode(const struct inode *inode, const char *function,
+			  unsigned int line, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	if (!ext4_warning_ratelimit(inode->i_sb))
+		return;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: "
+	       "inode #%lu: comm %s: %pV\n", inode->i_sb->s_id,
+	       function, line, inode->i_ino, current->comm, &vaf);
+	va_end(args);
+}
+
+void __ext4_grp_locked_error(const char *function, unsigned int line,
+			     struct super_block *sb, ext4_group_t grp,
+			     unsigned long ino, ext4_fsblk_t block,
+			     const char *fmt, ...)
+__releases(bitlock)
+__acquires(bitlock)
+{
+	struct va_format vaf;
+	va_list args;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
+		return;
+
+	trace_ext4_error(sb, function, line);
+	__save_error_info(sb, EFSCORRUPTED, ino, block, function, line);
+
+	if (ext4_error_ratelimit(sb)) {
+		va_start(args, fmt);
+		vaf.fmt = fmt;
+		vaf.va = &args;
+		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
+		       sb->s_id, function, line, grp);
+		if (ino)
+			printk(KERN_CONT "inode %lu: ", ino);
+		if (block)
+			printk(KERN_CONT "block %llu:",
+			       (unsigned long long) block);
+		printk(KERN_CONT "%pV\n", &vaf);
+		va_end(args);
+	}
+
+	if (test_opt(sb, WARN_ON_ERROR))
+		WARN_ON_ONCE(1);
+
+	if (test_opt(sb, ERRORS_CONT)) {
+		ext4_commit_super(sb, 0);
+		return;
+	}
+
+	ext4_unlock_group(sb, grp);
+	ext4_commit_super(sb, 1);
+	ext4_handle_error(sb);
+	/*
+	 * We only get here in the ERRORS_RO case; relocking the group
+	 * may be dangerous, but nothing bad will happen since the
+	 * filesystem will have already been marked read/only and the
+	 * journal has been aborted.  We return 1 as a hint to callers
+	 * who might what to use the return value from
+	 * ext4_grp_locked_error() to distinguish between the
+	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
+	 * aggressively from the ext4 function in question, with a
+	 * more appropriate error code.
+	 */
+	ext4_lock_group(sb, grp);
+	return;
+}
+
+void ext4_mark_group_bitmap_corrupted(struct super_block *sb,
+				     ext4_group_t group,
+				     unsigned int flags)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+	struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
+	int ret;
+
+	if (!grp || !gdp)
+		return;
+	if (flags & EXT4_GROUP_INFO_BBITMAP_CORRUPT) {
+		ret = ext4_test_and_set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
+					    &grp->bb_state);
+		if (!ret)
+			percpu_counter_sub(&sbi->s_freeclusters_counter,
+					   grp->bb_free);
+	}
+
+	if (flags & EXT4_GROUP_INFO_IBITMAP_CORRUPT) {
+		ret = ext4_test_and_set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT,
+					    &grp->bb_state);
+		if (!ret && gdp) {
+			int count;
+
+			count = ext4_free_inodes_count(sb, gdp);
+			percpu_counter_sub(&sbi->s_freeinodes_counter,
+					   count);
+		}
+	}
+}
+
+void ext4_update_dynamic_rev(struct super_block *sb)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
+		return;
+
+	ext4_warning(sb,
+		     "updating to rev %d because of new feature flag, "
+		     "running e2fsck is recommended",
+		     EXT4_DYNAMIC_REV);
+
+	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
+	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
+	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
+	/* leave es->s_feature_*compat flags alone */
+	/* es->s_uuid will be set by e2fsck if empty */
+
+	/*
+	 * The rest of the superblock fields should be zero, and if not it
+	 * means they are likely already in use, so leave them alone.  We
+	 * can leave it up to e2fsck to clean up any inconsistencies there.
+	 */
+}
+
+/*
+ * Open the external journal device
+ */
+static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
+{
+	struct block_device *bdev;
+
+	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
+	if (IS_ERR(bdev))
+		goto fail;
+	return bdev;
+
+fail:
+	ext4_msg(sb, KERN_ERR,
+		 "failed to open journal device unknown-block(%u,%u) %ld",
+		 MAJOR(dev), MINOR(dev), PTR_ERR(bdev));
+	return NULL;
+}
+
+/*
+ * Release the journal device
+ */
+static void ext4_blkdev_put(struct block_device *bdev)
+{
+	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+}
+
+static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
+{
+	struct block_device *bdev;
+	bdev = sbi->s_journal_bdev;
+	if (bdev) {
+		/*
+		 * Invalidate the journal device's buffers.  We don't want them
+		 * floating about in memory - the physical journal device may
+		 * hotswapped, and it breaks the `ro-after' testing code.
+		 */
+		invalidate_bdev(bdev);
+		ext4_blkdev_put(bdev);
+		sbi->s_journal_bdev = NULL;
+	}
+}
+
+static inline struct inode *orphan_list_entry(struct list_head *l)
+{
+	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
+}
+
+static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
+{
+	struct list_head *l;
+
+	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
+		 le32_to_cpu(sbi->s_es->s_last_orphan));
+
+	printk(KERN_ERR "sb_info orphan list:\n");
+	list_for_each(l, &sbi->s_orphan) {
+		struct inode *inode = orphan_list_entry(l);
+		printk(KERN_ERR "  "
+		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
+		       inode->i_sb->s_id, inode->i_ino, inode,
+		       inode->i_mode, inode->i_nlink,
+		       NEXT_ORPHAN(inode));
+	}
+}
+
+#ifdef CONFIG_QUOTA
+static int ext4_quota_off(struct super_block *sb, int type);
+
+static inline void ext4_quota_off_umount(struct super_block *sb)
+{
+	int type;
+
+	/* Use our quota_off function to clear inode flags etc. */
+	for (type = 0; type < EXT4_MAXQUOTAS; type++)
+		ext4_quota_off(sb, type);
+}
+
+/*
+ * This is a helper function which is used in the mount/remount
+ * codepaths (which holds s_umount) to fetch the quota file name.
+ */
+static inline char *get_qf_name(struct super_block *sb,
+				struct ext4_sb_info *sbi,
+				int type)
+{
+	return rcu_dereference_protected(sbi->s_qf_names[type],
+					 lockdep_is_held(&sb->s_umount));
+}
+#else
+static inline void ext4_quota_off_umount(struct super_block *sb)
+{
+}
+#endif
+
+static void ext4_put_super(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct buffer_head **group_desc;
+	struct flex_groups **flex_groups;
+	int aborted = 0;
+	int i, err;
+
+	/*
+	 * Unregister sysfs before destroying jbd2 journal.
+	 * Since we could still access attr_journal_task attribute via sysfs
+	 * path which could have sbi->s_journal->j_task as NULL
+	 * Unregister sysfs before flush sbi->s_error_work.
+	 * Since user may read /proc/fs/ext4/xx/mb_groups during umount, If
+	 * read metadata verify failed then will queue error work.
+	 * flush_stashed_error_work will call start_this_handle may trigger
+	 * BUG_ON.
+	 */
+	ext4_unregister_sysfs(sb);
+
+	ext4_unregister_li_request(sb);
+	ext4_quota_off_umount(sb);
+
+	destroy_workqueue(sbi->rsv_conversion_wq);
+
+	if (sbi->s_journal) {
+		aborted = is_journal_aborted(sbi->s_journal);
+		err = jbd2_journal_destroy(sbi->s_journal);
+		sbi->s_journal = NULL;
+		if ((err < 0) && !aborted) {
+			ext4_abort(sb, -err, "Couldn't clean up the journal");
+		}
+	}
+
+	ext4_es_unregister_shrinker(sbi);
+	del_timer_sync(&sbi->s_err_report);
+	ext4_release_system_zone(sb);
+	ext4_mb_release(sb);
+	ext4_ext_release(sb);
+
+	if (!sb_rdonly(sb) && !aborted) {
+		ext4_clear_feature_journal_needs_recovery(sb);
+		es->s_state = cpu_to_le16(sbi->s_mount_state);
+	}
+	if (!sb_rdonly(sb))
+		ext4_commit_super(sb, 1);
+
+	rcu_read_lock();
+	group_desc = rcu_dereference(sbi->s_group_desc);
+	for (i = 0; i < sbi->s_gdb_count; i++)
+		brelse(group_desc[i]);
+	kvfree(group_desc);
+	flex_groups = rcu_dereference(sbi->s_flex_groups);
+	if (flex_groups) {
+		for (i = 0; i < sbi->s_flex_groups_allocated; i++)
+			kvfree(flex_groups[i]);
+		kvfree(flex_groups);
+	}
+	rcu_read_unlock();
+	percpu_counter_destroy(&sbi->s_freeclusters_counter);
+	percpu_counter_destroy(&sbi->s_freeinodes_counter);
+	percpu_counter_destroy(&sbi->s_dirs_counter);
+	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
+	percpu_counter_destroy(&sbi->s_sra_exceeded_retry_limit);
+	percpu_free_rwsem(&sbi->s_writepages_rwsem);
+#ifdef CONFIG_QUOTA
+	for (i = 0; i < EXT4_MAXQUOTAS; i++)
+		kfree(get_qf_name(sb, sbi, i));
+#endif
+
+	/* Debugging code just in case the in-memory inode orphan list
+	 * isn't empty.  The on-disk one can be non-empty if we've
+	 * detected an error and taken the fs readonly, but the
+	 * in-memory list had better be clean by this point. */
+	if (!list_empty(&sbi->s_orphan))
+		dump_orphan_list(sb, sbi);
+	J_ASSERT(list_empty(&sbi->s_orphan));
+
+	sync_blockdev(sb->s_bdev);
+	invalidate_bdev(sb->s_bdev);
+	if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) {
+		sync_blockdev(sbi->s_journal_bdev);
+		ext4_blkdev_remove(sbi);
+	}
+
+	ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+	sbi->s_ea_inode_cache = NULL;
+
+	ext4_xattr_destroy_cache(sbi->s_ea_block_cache);
+	sbi->s_ea_block_cache = NULL;
+
+	ext4_stop_mmpd(sbi);
+
+	brelse(sbi->s_sbh);
+	sb->s_fs_info = NULL;
+	/*
+	 * Now that we are completely done shutting down the
+	 * superblock, we need to actually destroy the kobject.
+	 */
+	kobject_put(&sbi->s_kobj);
+	wait_for_completion(&sbi->s_kobj_unregister);
+	if (sbi->s_chksum_driver)
+		crypto_free_shash(sbi->s_chksum_driver);
+	kfree(sbi->s_blockgroup_lock);
+	fs_put_dax(sbi->s_daxdev);
+	fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
+#ifdef CONFIG_UNICODE
+	utf8_unload(sb->s_encoding);
+#endif
+	kfree(sbi);
+}
+
+static struct kmem_cache *ext4_inode_cachep;
+
+/*
+ * Called inside transaction, so use GFP_NOFS
+ */
+static struct inode *ext4_alloc_inode(struct super_block *sb)
+{
+	struct ext4_inode_info *ei;
+
+	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+
+	inode_set_iversion(&ei->vfs_inode, 1);
+	ei->i_flags = 0;
+	spin_lock_init(&ei->i_raw_lock);
+	INIT_LIST_HEAD(&ei->i_prealloc_list);
+	atomic_set(&ei->i_prealloc_active, 0);
+	spin_lock_init(&ei->i_prealloc_lock);
+	ext4_es_init_tree(&ei->i_es_tree);
+	rwlock_init(&ei->i_es_lock);
+	INIT_LIST_HEAD(&ei->i_es_list);
+	ei->i_es_all_nr = 0;
+	ei->i_es_shk_nr = 0;
+	ei->i_es_shrink_lblk = 0;
+	ei->i_reserved_data_blocks = 0;
+	spin_lock_init(&(ei->i_block_reservation_lock));
+	ext4_init_pending_tree(&ei->i_pending_tree);
+#ifdef CONFIG_QUOTA
+	ei->i_reserved_quota = 0;
+	memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
+#endif
+	ei->jinode = NULL;
+	INIT_LIST_HEAD(&ei->i_rsv_conversion_list);
+	spin_lock_init(&ei->i_completed_io_lock);
+	ei->i_sync_tid = 0;
+	ei->i_datasync_tid = 0;
+	atomic_set(&ei->i_unwritten, 0);
+	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
+	ext4_fc_init_inode(&ei->vfs_inode);
+	mutex_init(&ei->i_fc_lock);
+	return &ei->vfs_inode;
+}
+
+static int ext4_drop_inode(struct inode *inode)
+{
+	int drop = generic_drop_inode(inode);
+
+	if (!drop)
+		drop = fscrypt_drop_inode(inode);
+
+	trace_ext4_drop_inode(inode, drop);
+	return drop;
+}
+
+static void ext4_free_in_core_inode(struct inode *inode)
+{
+	fscrypt_free_inode(inode);
+	if (!list_empty(&(EXT4_I(inode)->i_fc_list))) {
+		pr_warn("%s: inode %ld still in fc list",
+			__func__, inode->i_ino);
+	}
+	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
+}
+
+static void ext4_destroy_inode(struct inode *inode)
+{
+	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
+		ext4_msg(inode->i_sb, KERN_ERR,
+			 "Inode %lu (%p): orphan list check failed!",
+			 inode->i_ino, EXT4_I(inode));
+		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
+				EXT4_I(inode), sizeof(struct ext4_inode_info),
+				true);
+		dump_stack();
+	}
+
+	if (EXT4_I(inode)->i_reserved_data_blocks)
+		ext4_msg(inode->i_sb, KERN_ERR,
+			 "Inode %lu (%p): i_reserved_data_blocks (%u) not cleared!",
+			 inode->i_ino, EXT4_I(inode),
+			 EXT4_I(inode)->i_reserved_data_blocks);
+}
+
+static void init_once(void *foo)
+{
+	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
+
+	INIT_LIST_HEAD(&ei->i_orphan);
+	init_rwsem(&ei->xattr_sem);
+	init_rwsem(&ei->i_data_sem);
+	init_rwsem(&ei->i_mmap_sem);
+	inode_init_once(&ei->vfs_inode);
+	ext4_fc_init_inode(&ei->vfs_inode);
+}
+
+static int __init init_inodecache(void)
+{
+	ext4_inode_cachep = kmem_cache_create_usercopy("ext4_inode_cache",
+				sizeof(struct ext4_inode_info), 0,
+				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
+					SLAB_ACCOUNT),
+				offsetof(struct ext4_inode_info, i_data),
+				sizeof_field(struct ext4_inode_info, i_data),
+				init_once);
+	if (ext4_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(ext4_inode_cachep);
+}
+
+void ext4_clear_inode(struct inode *inode)
+{
+	ext4_fc_del(inode);
+	invalidate_inode_buffers(inode);
+	clear_inode(inode);
+	ext4_discard_preallocations(inode, 0);
+	ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
+	dquot_drop(inode);
+	if (EXT4_I(inode)->jinode) {
+		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
+					       EXT4_I(inode)->jinode);
+		jbd2_free_inode(EXT4_I(inode)->jinode);
+		EXT4_I(inode)->jinode = NULL;
+	}
+	fscrypt_put_encryption_info(inode);
+	fsverity_cleanup_inode(inode);
+}
+
+static struct inode *ext4_nfs_get_inode(struct super_block *sb,
+					u64 ino, u32 generation)
+{
+	struct inode *inode;
+
+	/*
+	 * Currently we don't know the generation for parent directory, so
+	 * a generation of 0 means "accept any"
+	 */
+	inode = ext4_iget(sb, ino, EXT4_IGET_HANDLE);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	if (generation && inode->i_generation != generation) {
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+
+	return inode;
+}
+
+static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
+					int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    ext4_nfs_get_inode);
+}
+
+static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
+					int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    ext4_nfs_get_inode);
+}
+
+static int ext4_nfs_commit_metadata(struct inode *inode)
+{
+	struct writeback_control wbc = {
+		.sync_mode = WB_SYNC_ALL
+	};
+
+	trace_ext4_nfs_commit_metadata(inode);
+	return ext4_write_inode(inode, &wbc);
+}
+
+/*
+ * Try to release metadata pages (indirect blocks, directories) which are
+ * mapped via the block device.  Since these pages could have journal heads
+ * which would prevent try_to_free_buffers() from freeing them, we must use
+ * jbd2 layer's try_to_free_buffers() function to release them.
+ */
+static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
+				 gfp_t wait)
+{
+	journal_t *journal = EXT4_SB(sb)->s_journal;
+
+	WARN_ON(PageChecked(page));
+	if (!page_has_buffers(page))
+		return 0;
+	if (journal)
+		return jbd2_journal_try_to_free_buffers(journal, page);
+
+	return try_to_free_buffers(page);
+}
+
+#ifdef CONFIG_FS_ENCRYPTION
+static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
+{
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
+				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
+}
+
+static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
+							void *fs_data)
+{
+	handle_t *handle = fs_data;
+	int res, res2, credits, retries = 0;
+
+	/*
+	 * Encrypting the root directory is not allowed because e2fsck expects
+	 * lost+found to exist and be unencrypted, and encrypting the root
+	 * directory would imply encrypting the lost+found directory as well as
+	 * the filename "lost+found" itself.
+	 */
+	if (inode->i_ino == EXT4_ROOT_INO)
+		return -EPERM;
+
+	if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode)))
+		return -EINVAL;
+
+	if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
+		return -EOPNOTSUPP;
+
+	res = ext4_convert_inline_data(inode);
+	if (res)
+		return res;
+
+	/*
+	 * If a journal handle was specified, then the encryption context is
+	 * being set on a new inode via inheritance and is part of a larger
+	 * transaction to create the inode.  Otherwise the encryption context is
+	 * being set on an existing inode in its own transaction.  Only in the
+	 * latter case should the "retry on ENOSPC" logic be used.
+	 */
+
+	if (handle) {
+		res = ext4_xattr_set_handle(handle, inode,
+					    EXT4_XATTR_INDEX_ENCRYPTION,
+					    EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+					    ctx, len, 0);
+		if (!res) {
+			ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+			ext4_clear_inode_state(inode,
+					EXT4_STATE_MAY_INLINE_DATA);
+			/*
+			 * Update inode->i_flags - S_ENCRYPTED will be enabled,
+			 * S_DAX may be disabled
+			 */
+			ext4_set_inode_flags(inode, false);
+		}
+		return res;
+	}
+
+	res = dquot_initialize(inode);
+	if (res)
+		return res;
+retry:
+	res = ext4_xattr_set_credits(inode, len, false /* is_create */,
+				     &credits);
+	if (res)
+		return res;
+
+	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION,
+				    EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+				    ctx, len, 0);
+	if (!res) {
+		ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+		/*
+		 * Update inode->i_flags - S_ENCRYPTED will be enabled,
+		 * S_DAX may be disabled
+		 */
+		ext4_set_inode_flags(inode, false);
+		res = ext4_mark_inode_dirty(handle, inode);
+		if (res)
+			EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
+	}
+	res2 = ext4_journal_stop(handle);
+
+	if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+	if (!res)
+		res = res2;
+	return res;
+}
+
+static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb)
+{
+	return EXT4_SB(sb)->s_dummy_enc_policy.policy;
+}
+
+static bool ext4_has_stable_inodes(struct super_block *sb)
+{
+	return ext4_has_feature_stable_inodes(sb);
+}
+
+static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
+				       int *ino_bits_ret, int *lblk_bits_ret)
+{
+	*ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count);
+	*lblk_bits_ret = 8 * sizeof(ext4_lblk_t);
+}
+
+static const struct fscrypt_operations ext4_cryptops = {
+	.key_prefix		= "ext4:",
+	.get_context		= ext4_get_context,
+	.set_context		= ext4_set_context,
+	.get_dummy_policy	= ext4_get_dummy_policy,
+	.empty_dir		= ext4_empty_dir,
+	.max_namelen		= EXT4_NAME_LEN,
+	.has_stable_inodes	= ext4_has_stable_inodes,
+	.get_ino_and_lblk_bits	= ext4_get_ino_and_lblk_bits,
+};
+#endif
+
+#ifdef CONFIG_QUOTA
+static const char * const quotatypes[] = INITQFNAMES;
+#define QTYPE2NAME(t) (quotatypes[t])
+
+static int ext4_write_dquot(struct dquot *dquot);
+static int ext4_acquire_dquot(struct dquot *dquot);
+static int ext4_release_dquot(struct dquot *dquot);
+static int ext4_mark_dquot_dirty(struct dquot *dquot);
+static int ext4_write_info(struct super_block *sb, int type);
+static int ext4_quota_on(struct super_block *sb, int type, int format_id,
+			 const struct path *path);
+static int ext4_quota_on_mount(struct super_block *sb, int type);
+static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
+			       size_t len, loff_t off);
+static ssize_t ext4_quota_write(struct super_block *sb, int type,
+				const char *data, size_t len, loff_t off);
+static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
+			     unsigned int flags);
+static int ext4_enable_quotas(struct super_block *sb);
+
+static struct dquot **ext4_get_dquots(struct inode *inode)
+{
+	return EXT4_I(inode)->i_dquot;
+}
+
+static const struct dquot_operations ext4_quota_operations = {
+	.get_reserved_space	= ext4_get_reserved_space,
+	.write_dquot		= ext4_write_dquot,
+	.acquire_dquot		= ext4_acquire_dquot,
+	.release_dquot		= ext4_release_dquot,
+	.mark_dirty		= ext4_mark_dquot_dirty,
+	.write_info		= ext4_write_info,
+	.alloc_dquot		= dquot_alloc,
+	.destroy_dquot		= dquot_destroy,
+	.get_projid		= ext4_get_projid,
+	.get_inode_usage	= ext4_get_inode_usage,
+	.get_next_id		= dquot_get_next_id,
+};
+
+static const struct quotactl_ops ext4_qctl_operations = {
+	.quota_on	= ext4_quota_on,
+	.quota_off	= ext4_quota_off,
+	.quota_sync	= dquot_quota_sync,
+	.get_state	= dquot_get_state,
+	.set_info	= dquot_set_dqinfo,
+	.get_dqblk	= dquot_get_dqblk,
+	.set_dqblk	= dquot_set_dqblk,
+	.get_nextdqblk	= dquot_get_next_dqblk,
+};
+#endif
+
+static const struct super_operations ext4_sops = {
+	.alloc_inode	= ext4_alloc_inode,
+	.free_inode	= ext4_free_in_core_inode,
+	.destroy_inode	= ext4_destroy_inode,
+	.write_inode	= ext4_write_inode,
+	.dirty_inode	= ext4_dirty_inode,
+	.drop_inode	= ext4_drop_inode,
+	.evict_inode	= ext4_evict_inode,
+	.put_super	= ext4_put_super,
+	.sync_fs	= ext4_sync_fs,
+	.freeze_fs	= ext4_freeze,
+	.unfreeze_fs	= ext4_unfreeze,
+	.statfs		= ext4_statfs,
+	.remount_fs	= ext4_remount,
+	.show_options	= ext4_show_options,
+#ifdef CONFIG_QUOTA
+	.quota_read	= ext4_quota_read,
+	.quota_write	= ext4_quota_write,
+	.get_dquots	= ext4_get_dquots,
+#endif
+	.bdev_try_to_free_page = bdev_try_to_free_page,
+};
+
+static const struct export_operations ext4_export_ops = {
+	.fh_to_dentry = ext4_fh_to_dentry,
+	.fh_to_parent = ext4_fh_to_parent,
+	.get_parent = ext4_get_parent,
+	.commit_metadata = ext4_nfs_commit_metadata,
+};
+
+enum {
+	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
+	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
+	Opt_nouid32, Opt_debug, Opt_removed,
+	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
+	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
+	Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
+	Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
+	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
+	Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
+	Opt_inlinecrypt,
+	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
+	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
+	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
+	Opt_usrquota, Opt_grpquota, Opt_prjquota, Opt_i_version,
+	Opt_dax, Opt_dax_always, Opt_dax_inode, Opt_dax_never,
+	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_warn_on_error,
+	Opt_nowarn_on_error, Opt_mblk_io_submit,
+	Opt_lazytime, Opt_nolazytime, Opt_debug_want_extra_isize,
+	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
+	Opt_inode_readahead_blks, Opt_journal_ioprio,
+	Opt_dioread_nolock, Opt_dioread_lock,
+	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
+	Opt_max_dir_size_kb, Opt_nojournal_checksum, Opt_nombcache,
+	Opt_prefetch_block_bitmaps,
+#ifdef CONFIG_EXT4_DEBUG
+	Opt_fc_debug_max_replay, Opt_fc_debug_force
+#endif
+};
+
+static const match_table_t tokens = {
+	{Opt_bsd_df, "bsddf"},
+	{Opt_minix_df, "minixdf"},
+	{Opt_grpid, "grpid"},
+	{Opt_grpid, "bsdgroups"},
+	{Opt_nogrpid, "nogrpid"},
+	{Opt_nogrpid, "sysvgroups"},
+	{Opt_resgid, "resgid=%u"},
+	{Opt_resuid, "resuid=%u"},
+	{Opt_sb, "sb=%u"},
+	{Opt_err_cont, "errors=continue"},
+	{Opt_err_panic, "errors=panic"},
+	{Opt_err_ro, "errors=remount-ro"},
+	{Opt_nouid32, "nouid32"},
+	{Opt_debug, "debug"},
+	{Opt_removed, "oldalloc"},
+	{Opt_removed, "orlov"},
+	{Opt_user_xattr, "user_xattr"},
+	{Opt_nouser_xattr, "nouser_xattr"},
+	{Opt_acl, "acl"},
+	{Opt_noacl, "noacl"},
+	{Opt_noload, "norecovery"},
+	{Opt_noload, "noload"},
+	{Opt_removed, "nobh"},
+	{Opt_removed, "bh"},
+	{Opt_commit, "commit=%u"},
+	{Opt_min_batch_time, "min_batch_time=%u"},
+	{Opt_max_batch_time, "max_batch_time=%u"},
+	{Opt_journal_dev, "journal_dev=%u"},
+	{Opt_journal_path, "journal_path=%s"},
+	{Opt_journal_checksum, "journal_checksum"},
+	{Opt_nojournal_checksum, "nojournal_checksum"},
+	{Opt_journal_async_commit, "journal_async_commit"},
+	{Opt_abort, "abort"},
+	{Opt_data_journal, "data=journal"},
+	{Opt_data_ordered, "data=ordered"},
+	{Opt_data_writeback, "data=writeback"},
+	{Opt_data_err_abort, "data_err=abort"},
+	{Opt_data_err_ignore, "data_err=ignore"},
+	{Opt_offusrjquota, "usrjquota="},
+	{Opt_usrjquota, "usrjquota=%s"},
+	{Opt_offgrpjquota, "grpjquota="},
+	{Opt_grpjquota, "grpjquota=%s"},
+	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
+	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
+	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
+	{Opt_grpquota, "grpquota"},
+	{Opt_noquota, "noquota"},
+	{Opt_quota, "quota"},
+	{Opt_usrquota, "usrquota"},
+	{Opt_prjquota, "prjquota"},
+	{Opt_barrier, "barrier=%u"},
+	{Opt_barrier, "barrier"},
+	{Opt_nobarrier, "nobarrier"},
+	{Opt_i_version, "i_version"},
+	{Opt_dax, "dax"},
+	{Opt_dax_always, "dax=always"},
+	{Opt_dax_inode, "dax=inode"},
+	{Opt_dax_never, "dax=never"},
+	{Opt_stripe, "stripe=%u"},
+	{Opt_delalloc, "delalloc"},
+	{Opt_warn_on_error, "warn_on_error"},
+	{Opt_nowarn_on_error, "nowarn_on_error"},
+	{Opt_lazytime, "lazytime"},
+	{Opt_nolazytime, "nolazytime"},
+	{Opt_debug_want_extra_isize, "debug_want_extra_isize=%u"},
+	{Opt_nodelalloc, "nodelalloc"},
+	{Opt_removed, "mblk_io_submit"},
+	{Opt_removed, "nomblk_io_submit"},
+	{Opt_block_validity, "block_validity"},
+	{Opt_noblock_validity, "noblock_validity"},
+	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
+	{Opt_journal_ioprio, "journal_ioprio=%u"},
+	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
+	{Opt_auto_da_alloc, "auto_da_alloc"},
+	{Opt_noauto_da_alloc, "noauto_da_alloc"},
+	{Opt_dioread_nolock, "dioread_nolock"},
+	{Opt_dioread_lock, "nodioread_nolock"},
+	{Opt_dioread_lock, "dioread_lock"},
+	{Opt_discard, "discard"},
+	{Opt_nodiscard, "nodiscard"},
+	{Opt_init_itable, "init_itable=%u"},
+	{Opt_init_itable, "init_itable"},
+	{Opt_noinit_itable, "noinit_itable"},
+#ifdef CONFIG_EXT4_DEBUG
+	{Opt_fc_debug_force, "fc_debug_force"},
+	{Opt_fc_debug_max_replay, "fc_debug_max_replay=%u"},
+#endif
+	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
+	{Opt_test_dummy_encryption, "test_dummy_encryption=%s"},
+	{Opt_test_dummy_encryption, "test_dummy_encryption"},
+	{Opt_inlinecrypt, "inlinecrypt"},
+	{Opt_nombcache, "nombcache"},
+	{Opt_nombcache, "no_mbcache"},	/* for backward compatibility */
+	{Opt_prefetch_block_bitmaps, "prefetch_block_bitmaps"},
+	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
+	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
+	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
+	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
+	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
+	{Opt_err, NULL},
+};
+
+static ext4_fsblk_t get_sb_block(void **data)
+{
+	ext4_fsblk_t	sb_block;
+	char		*options = (char *) *data;
+
+	if (!options || strncmp(options, "sb=", 3) != 0)
+		return 1;	/* Default location */
+
+	options += 3;
+	/* TODO: use simple_strtoll with >32bit ext4 */
+	sb_block = simple_strtoul(options, &options, 0);
+	if (*options && *options != ',') {
+		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
+		       (char *) *data);
+		return 1;
+	}
+	if (*options == ',')
+		options++;
+	*data = (void *) options;
+
+	return sb_block;
+}
+
+#define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
+static const char deprecated_msg[] =
+	"Mount option \"%s\" will be removed by %s\n"
+	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
+
+#ifdef CONFIG_QUOTA
+static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	char *qname, *old_qname = get_qf_name(sb, sbi, qtype);
+	int ret = -1;
+
+	if (sb_any_quota_loaded(sb) && !old_qname) {
+		ext4_msg(sb, KERN_ERR,
+			"Cannot change journaled "
+			"quota options when quota turned on");
+		return -1;
+	}
+	if (ext4_has_feature_quota(sb)) {
+		ext4_msg(sb, KERN_INFO, "Journaled quota options "
+			 "ignored when QUOTA feature is enabled");
+		return 1;
+	}
+	qname = match_strdup(args);
+	if (!qname) {
+		ext4_msg(sb, KERN_ERR,
+			"Not enough memory for storing quotafile name");
+		return -1;
+	}
+	if (old_qname) {
+		if (strcmp(old_qname, qname) == 0)
+			ret = 1;
+		else
+			ext4_msg(sb, KERN_ERR,
+				 "%s quota file already specified",
+				 QTYPE2NAME(qtype));
+		goto errout;
+	}
+	if (strchr(qname, '/')) {
+		ext4_msg(sb, KERN_ERR,
+			"quotafile must be on filesystem root");
+		goto errout;
+	}
+	rcu_assign_pointer(sbi->s_qf_names[qtype], qname);
+	set_opt(sb, QUOTA);
+	return 1;
+errout:
+	kfree(qname);
+	return ret;
+}
+
+static int clear_qf_name(struct super_block *sb, int qtype)
+{
+
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	char *old_qname = get_qf_name(sb, sbi, qtype);
+
+	if (sb_any_quota_loaded(sb) && old_qname) {
+		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
+			" when quota turned on");
+		return -1;
+	}
+	rcu_assign_pointer(sbi->s_qf_names[qtype], NULL);
+	synchronize_rcu();
+	kfree(old_qname);
+	return 1;
+}
+#endif
+
+#define MOPT_SET	0x0001
+#define MOPT_CLEAR	0x0002
+#define MOPT_NOSUPPORT	0x0004
+#define MOPT_EXPLICIT	0x0008
+#define MOPT_CLEAR_ERR	0x0010
+#define MOPT_GTE0	0x0020
+#ifdef CONFIG_QUOTA
+#define MOPT_Q		0
+#define MOPT_QFMT	0x0040
+#else
+#define MOPT_Q		MOPT_NOSUPPORT
+#define MOPT_QFMT	MOPT_NOSUPPORT
+#endif
+#define MOPT_DATAJ	0x0080
+#define MOPT_NO_EXT2	0x0100
+#define MOPT_NO_EXT3	0x0200
+#define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
+#define MOPT_STRING	0x0400
+#define MOPT_SKIP	0x0800
+#define	MOPT_2		0x1000
+
+static const struct mount_opts {
+	int	token;
+	int	mount_opt;
+	int	flags;
+} ext4_mount_opts[] = {
+	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
+	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
+	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
+	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
+	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
+	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
+	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
+	 MOPT_EXT4_ONLY | MOPT_SET},
+	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
+	 MOPT_EXT4_ONLY | MOPT_CLEAR},
+	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
+	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
+	{Opt_delalloc, EXT4_MOUNT_DELALLOC,
+	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
+	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
+	 MOPT_EXT4_ONLY | MOPT_CLEAR},
+	{Opt_warn_on_error, EXT4_MOUNT_WARN_ON_ERROR, MOPT_SET},
+	{Opt_nowarn_on_error, EXT4_MOUNT_WARN_ON_ERROR, MOPT_CLEAR},
+	{Opt_commit, 0, MOPT_NO_EXT2},
+	{Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
+	 MOPT_EXT4_ONLY | MOPT_CLEAR},
+	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
+	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
+	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
+				    EXT4_MOUNT_JOURNAL_CHECKSUM),
+	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
+	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
+	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
+	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
+	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
+	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT,
+	 MOPT_NO_EXT2},
+	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT,
+	 MOPT_NO_EXT2},
+	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
+	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
+	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
+	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
+	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
+	{Opt_commit, 0, MOPT_GTE0},
+	{Opt_max_batch_time, 0, MOPT_GTE0},
+	{Opt_min_batch_time, 0, MOPT_GTE0},
+	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
+	{Opt_init_itable, 0, MOPT_GTE0},
+	{Opt_dax, EXT4_MOUNT_DAX_ALWAYS, MOPT_SET | MOPT_SKIP},
+	{Opt_dax_always, EXT4_MOUNT_DAX_ALWAYS,
+		MOPT_EXT4_ONLY | MOPT_SET | MOPT_SKIP},
+	{Opt_dax_inode, EXT4_MOUNT2_DAX_INODE,
+		MOPT_EXT4_ONLY | MOPT_SET | MOPT_SKIP},
+	{Opt_dax_never, EXT4_MOUNT2_DAX_NEVER,
+		MOPT_EXT4_ONLY | MOPT_SET | MOPT_SKIP},
+	{Opt_stripe, 0, MOPT_GTE0},
+	{Opt_resuid, 0, MOPT_GTE0},
+	{Opt_resgid, 0, MOPT_GTE0},
+	{Opt_journal_dev, 0, MOPT_NO_EXT2 | MOPT_GTE0},
+	{Opt_journal_path, 0, MOPT_NO_EXT2 | MOPT_STRING},
+	{Opt_journal_ioprio, 0, MOPT_NO_EXT2 | MOPT_GTE0},
+	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
+	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
+	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA,
+	 MOPT_NO_EXT2 | MOPT_DATAJ},
+	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
+	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
+	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
+#else
+	{Opt_acl, 0, MOPT_NOSUPPORT},
+	{Opt_noacl, 0, MOPT_NOSUPPORT},
+#endif
+	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
+	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
+	{Opt_debug_want_extra_isize, 0, MOPT_GTE0},
+	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
+	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
+							MOPT_SET | MOPT_Q},
+	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
+							MOPT_SET | MOPT_Q},
+	{Opt_prjquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_PRJQUOTA,
+							MOPT_SET | MOPT_Q},
+	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
+		       EXT4_MOUNT_GRPQUOTA | EXT4_MOUNT_PRJQUOTA),
+							MOPT_CLEAR | MOPT_Q},
+	{Opt_usrjquota, 0, MOPT_Q | MOPT_STRING},
+	{Opt_grpjquota, 0, MOPT_Q | MOPT_STRING},
+	{Opt_offusrjquota, 0, MOPT_Q},
+	{Opt_offgrpjquota, 0, MOPT_Q},
+	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
+	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
+	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
+	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
+	{Opt_test_dummy_encryption, 0, MOPT_STRING},
+	{Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
+	{Opt_prefetch_block_bitmaps, EXT4_MOUNT_PREFETCH_BLOCK_BITMAPS,
+	 MOPT_SET},
+#ifdef CONFIG_EXT4_DEBUG
+	{Opt_fc_debug_force, EXT4_MOUNT2_JOURNAL_FAST_COMMIT,
+	 MOPT_SET | MOPT_2 | MOPT_EXT4_ONLY},
+	{Opt_fc_debug_max_replay, 0, MOPT_GTE0},
+#endif
+	{Opt_err, 0, 0}
+};
+
+#ifdef CONFIG_UNICODE
+static const struct ext4_sb_encodings {
+	__u16 magic;
+	char *name;
+	char *version;
+} ext4_sb_encoding_map[] = {
+	{EXT4_ENC_UTF8_12_1, "utf8", "12.1.0"},
+};
+
+static int ext4_sb_read_encoding(const struct ext4_super_block *es,
+				 const struct ext4_sb_encodings **encoding,
+				 __u16 *flags)
+{
+	__u16 magic = le16_to_cpu(es->s_encoding);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ext4_sb_encoding_map); i++)
+		if (magic == ext4_sb_encoding_map[i].magic)
+			break;
+
+	if (i >= ARRAY_SIZE(ext4_sb_encoding_map))
+		return -EINVAL;
+
+	*encoding = &ext4_sb_encoding_map[i];
+	*flags = le16_to_cpu(es->s_encoding_flags);
+
+	return 0;
+}
+#endif
+
+static int ext4_set_test_dummy_encryption(struct super_block *sb,
+					  const char *opt,
+					  const substring_t *arg,
+					  bool is_remount)
+{
+#ifdef CONFIG_FS_ENCRYPTION
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int err;
+
+	if (!ext4_has_feature_encrypt(sb)) {
+		ext4_msg(sb, KERN_WARNING,
+			 "test_dummy_encryption requires encrypt feature");
+		return -1;
+	}
+
+	/*
+	 * This mount option is just for testing, and it's not worthwhile to
+	 * implement the extra complexity (e.g. RCU protection) that would be
+	 * needed to allow it to be set or changed during remount.  We do allow
+	 * it to be specified during remount, but only if there is no change.
+	 */
+	if (is_remount && !sbi->s_dummy_enc_policy.policy) {
+		ext4_msg(sb, KERN_WARNING,
+			 "Can't set test_dummy_encryption on remount");
+		return -1;
+	}
+	err = fscrypt_set_test_dummy_encryption(sb, arg->from,
+						&sbi->s_dummy_enc_policy);
+	if (err) {
+		if (err == -EEXIST)
+			ext4_msg(sb, KERN_WARNING,
+				 "Can't change test_dummy_encryption on remount");
+		else if (err == -EINVAL)
+			ext4_msg(sb, KERN_WARNING,
+				 "Value of option \"%s\" is unrecognized", opt);
+		else
+			ext4_msg(sb, KERN_WARNING,
+				 "Error processing option \"%s\" [%d]",
+				 opt, err);
+		return -1;
+	}
+	ext4_msg(sb, KERN_WARNING, "Test dummy encryption mode enabled");
+	return 1;
+#else
+	ext4_msg(sb, KERN_WARNING,
+		 "test_dummy_encryption option not supported");
+	return -1;
+
+#endif
+}
+
+static int handle_mount_opt(struct super_block *sb, char *opt, int token,
+			    substring_t *args, unsigned long *journal_devnum,
+			    unsigned int *journal_ioprio, int is_remount)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	const struct mount_opts *m;
+	kuid_t uid;
+	kgid_t gid;
+	int arg = 0;
+
+#ifdef CONFIG_QUOTA
+	if (token == Opt_usrjquota)
+		return set_qf_name(sb, USRQUOTA, &args[0]);
+	else if (token == Opt_grpjquota)
+		return set_qf_name(sb, GRPQUOTA, &args[0]);
+	else if (token == Opt_offusrjquota)
+		return clear_qf_name(sb, USRQUOTA);
+	else if (token == Opt_offgrpjquota)
+		return clear_qf_name(sb, GRPQUOTA);
+#endif
+	switch (token) {
+	case Opt_noacl:
+	case Opt_nouser_xattr:
+		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
+		break;
+	case Opt_sb:
+		return 1;	/* handled by get_sb_block() */
+	case Opt_removed:
+		ext4_msg(sb, KERN_WARNING, "Ignoring removed %s option", opt);
+		return 1;
+	case Opt_abort:
+		ext4_set_mount_flag(sb, EXT4_MF_FS_ABORTED);
+		return 1;
+	case Opt_i_version:
+		sb->s_flags |= SB_I_VERSION;
+		return 1;
+	case Opt_lazytime:
+		sb->s_flags |= SB_LAZYTIME;
+		return 1;
+	case Opt_nolazytime:
+		sb->s_flags &= ~SB_LAZYTIME;
+		return 1;
+	case Opt_inlinecrypt:
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+		sb->s_flags |= SB_INLINECRYPT;
+#else
+		ext4_msg(sb, KERN_ERR, "inline encryption not supported");
+#endif
+		return 1;
+	}
+
+	for (m = ext4_mount_opts; m->token != Opt_err; m++)
+		if (token == m->token)
+			break;
+
+	if (m->token == Opt_err) {
+		ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
+			 "or missing value", opt);
+		return -1;
+	}
+
+	if ((m->flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Mount option \"%s\" incompatible with ext2", opt);
+		return -1;
+	}
+	if ((m->flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Mount option \"%s\" incompatible with ext3", opt);
+		return -1;
+	}
+
+	if (args->from && !(m->flags & MOPT_STRING) && match_int(args, &arg))
+		return -1;
+	if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
+		return -1;
+	if (m->flags & MOPT_EXPLICIT) {
+		if (m->mount_opt & EXT4_MOUNT_DELALLOC) {
+			set_opt2(sb, EXPLICIT_DELALLOC);
+		} else if (m->mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) {
+			set_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM);
+		} else
+			return -1;
+	}
+	if (m->flags & MOPT_CLEAR_ERR)
+		clear_opt(sb, ERRORS_MASK);
+	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
+		ext4_msg(sb, KERN_ERR, "Cannot change quota "
+			 "options when quota turned on");
+		return -1;
+	}
+
+	if (m->flags & MOPT_NOSUPPORT) {
+		ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
+	} else if (token == Opt_commit) {
+		if (arg == 0)
+			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
+		else if (arg > INT_MAX / HZ) {
+			ext4_msg(sb, KERN_ERR,
+				 "Invalid commit interval %d, "
+				 "must be smaller than %d",
+				 arg, INT_MAX / HZ);
+			return -1;
+		}
+		sbi->s_commit_interval = HZ * arg;
+	} else if (token == Opt_debug_want_extra_isize) {
+		if ((arg & 1) ||
+		    (arg < 4) ||
+		    (arg > (sbi->s_inode_size - EXT4_GOOD_OLD_INODE_SIZE))) {
+			ext4_msg(sb, KERN_ERR,
+				 "Invalid want_extra_isize %d", arg);
+			return -1;
+		}
+		sbi->s_want_extra_isize = arg;
+	} else if (token == Opt_max_batch_time) {
+		sbi->s_max_batch_time = arg;
+	} else if (token == Opt_min_batch_time) {
+		sbi->s_min_batch_time = arg;
+	} else if (token == Opt_inode_readahead_blks) {
+		if (arg && (arg > (1 << 30) || !is_power_of_2(arg))) {
+			ext4_msg(sb, KERN_ERR,
+				 "EXT4-fs: inode_readahead_blks must be "
+				 "0 or a power of 2 smaller than 2^31");
+			return -1;
+		}
+		sbi->s_inode_readahead_blks = arg;
+	} else if (token == Opt_init_itable) {
+		set_opt(sb, INIT_INODE_TABLE);
+		if (!args->from)
+			arg = EXT4_DEF_LI_WAIT_MULT;
+		sbi->s_li_wait_mult = arg;
+	} else if (token == Opt_max_dir_size_kb) {
+		sbi->s_max_dir_size_kb = arg;
+#ifdef CONFIG_EXT4_DEBUG
+	} else if (token == Opt_fc_debug_max_replay) {
+		sbi->s_fc_debug_max_replay = arg;
+#endif
+	} else if (token == Opt_stripe) {
+		sbi->s_stripe = arg;
+	} else if (token == Opt_resuid) {
+		uid = make_kuid(current_user_ns(), arg);
+		if (!uid_valid(uid)) {
+			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
+			return -1;
+		}
+		sbi->s_resuid = uid;
+	} else if (token == Opt_resgid) {
+		gid = make_kgid(current_user_ns(), arg);
+		if (!gid_valid(gid)) {
+			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
+			return -1;
+		}
+		sbi->s_resgid = gid;
+	} else if (token == Opt_journal_dev) {
+		if (is_remount) {
+			ext4_msg(sb, KERN_ERR,
+				 "Cannot specify journal on remount");
+			return -1;
+		}
+		*journal_devnum = arg;
+	} else if (token == Opt_journal_path) {
+		char *journal_path;
+		struct inode *journal_inode;
+		struct path path;
+		int error;
+
+		if (is_remount) {
+			ext4_msg(sb, KERN_ERR,
+				 "Cannot specify journal on remount");
+			return -1;
+		}
+		journal_path = match_strdup(&args[0]);
+		if (!journal_path) {
+			ext4_msg(sb, KERN_ERR, "error: could not dup "
+				"journal device string");
+			return -1;
+		}
+
+		error = kern_path(journal_path, LOOKUP_FOLLOW, &path);
+		if (error) {
+			ext4_msg(sb, KERN_ERR, "error: could not find "
+				"journal device path: error %d", error);
+			kfree(journal_path);
+			return -1;
+		}
+
+		journal_inode = d_inode(path.dentry);
+		if (!S_ISBLK(journal_inode->i_mode)) {
+			ext4_msg(sb, KERN_ERR, "error: journal path %s "
+				"is not a block device", journal_path);
+			path_put(&path);
+			kfree(journal_path);
+			return -1;
+		}
+
+		*journal_devnum = new_encode_dev(journal_inode->i_rdev);
+		path_put(&path);
+		kfree(journal_path);
+	} else if (token == Opt_journal_ioprio) {
+		if (arg > 7) {
+			ext4_msg(sb, KERN_ERR, "Invalid journal IO priority"
+				 " (must be 0-7)");
+			return -1;
+		}
+		*journal_ioprio =
+			IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
+	} else if (token == Opt_test_dummy_encryption) {
+		return ext4_set_test_dummy_encryption(sb, opt, &args[0],
+						      is_remount);
+	} else if (m->flags & MOPT_DATAJ) {
+		if (is_remount) {
+			if (!sbi->s_journal)
+				ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
+			else if (test_opt(sb, DATA_FLAGS) != m->mount_opt) {
+				ext4_msg(sb, KERN_ERR,
+					 "Cannot change data mode on remount");
+				return -1;
+			}
+		} else {
+			clear_opt(sb, DATA_FLAGS);
+			sbi->s_mount_opt |= m->mount_opt;
+		}
+#ifdef CONFIG_QUOTA
+	} else if (m->flags & MOPT_QFMT) {
+		if (sb_any_quota_loaded(sb) &&
+		    sbi->s_jquota_fmt != m->mount_opt) {
+			ext4_msg(sb, KERN_ERR, "Cannot change journaled "
+				 "quota options when quota turned on");
+			return -1;
+		}
+		if (ext4_has_feature_quota(sb)) {
+			ext4_msg(sb, KERN_INFO,
+				 "Quota format mount options ignored "
+				 "when QUOTA feature is enabled");
+			return 1;
+		}
+		sbi->s_jquota_fmt = m->mount_opt;
+#endif
+	} else if (token == Opt_dax || token == Opt_dax_always ||
+		   token == Opt_dax_inode || token == Opt_dax_never) {
+#ifdef CONFIG_FS_DAX
+		switch (token) {
+		case Opt_dax:
+		case Opt_dax_always:
+			if (is_remount &&
+			    (!(sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) ||
+			     (sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER))) {
+			fail_dax_change_remount:
+				ext4_msg(sb, KERN_ERR, "can't change "
+					 "dax mount option while remounting");
+				return -1;
+			}
+			if (is_remount &&
+			    (test_opt(sb, DATA_FLAGS) ==
+			     EXT4_MOUNT_JOURNAL_DATA)) {
+				    ext4_msg(sb, KERN_ERR, "can't mount with "
+					     "both data=journal and dax");
+				    return -1;
+			}
+			ext4_msg(sb, KERN_WARNING,
+				"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
+			sbi->s_mount_opt |= EXT4_MOUNT_DAX_ALWAYS;
+			sbi->s_mount_opt2 &= ~EXT4_MOUNT2_DAX_NEVER;
+			break;
+		case Opt_dax_never:
+			if (is_remount &&
+			    (!(sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER) ||
+			     (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS)))
+				goto fail_dax_change_remount;
+			sbi->s_mount_opt2 |= EXT4_MOUNT2_DAX_NEVER;
+			sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS;
+			break;
+		case Opt_dax_inode:
+			if (is_remount &&
+			    ((sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) ||
+			     (sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER) ||
+			     !(sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_INODE)))
+				goto fail_dax_change_remount;
+			sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS;
+			sbi->s_mount_opt2 &= ~EXT4_MOUNT2_DAX_NEVER;
+			/* Strictly for printing options */
+			sbi->s_mount_opt2 |= EXT4_MOUNT2_DAX_INODE;
+			break;
+		}
+#else
+		ext4_msg(sb, KERN_INFO, "dax option not supported");
+		sbi->s_mount_opt2 |= EXT4_MOUNT2_DAX_NEVER;
+		sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS;
+		return -1;
+#endif
+	} else if (token == Opt_data_err_abort) {
+		sbi->s_mount_opt |= m->mount_opt;
+	} else if (token == Opt_data_err_ignore) {
+		sbi->s_mount_opt &= ~m->mount_opt;
+	} else {
+		if (!args->from)
+			arg = 1;
+		if (m->flags & MOPT_CLEAR)
+			arg = !arg;
+		else if (unlikely(!(m->flags & MOPT_SET))) {
+			ext4_msg(sb, KERN_WARNING,
+				 "buggy handling of option %s", opt);
+			WARN_ON(1);
+			return -1;
+		}
+		if (m->flags & MOPT_2) {
+			if (arg != 0)
+				sbi->s_mount_opt2 |= m->mount_opt;
+			else
+				sbi->s_mount_opt2 &= ~m->mount_opt;
+		} else {
+			if (arg != 0)
+				sbi->s_mount_opt |= m->mount_opt;
+			else
+				sbi->s_mount_opt &= ~m->mount_opt;
+		}
+	}
+	return 1;
+}
+
+static int parse_options(char *options, struct super_block *sb,
+			 unsigned long *journal_devnum,
+			 unsigned int *journal_ioprio,
+			 int is_remount)
+{
+	struct ext4_sb_info __maybe_unused *sbi = EXT4_SB(sb);
+	char *p, __maybe_unused *usr_qf_name, __maybe_unused *grp_qf_name;
+	substring_t args[MAX_OPT_ARGS];
+	int token;
+
+	if (!options)
+		return 1;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		if (!*p)
+			continue;
+		/*
+		 * Initialize args struct so we know whether arg was
+		 * found; some options take optional arguments.
+		 */
+		args[0].to = args[0].from = NULL;
+		token = match_token(p, tokens, args);
+		if (handle_mount_opt(sb, p, token, args, journal_devnum,
+				     journal_ioprio, is_remount) < 0)
+			return 0;
+	}
+#ifdef CONFIG_QUOTA
+	/*
+	 * We do the test below only for project quotas. 'usrquota' and
+	 * 'grpquota' mount options are allowed even without quota feature
+	 * to support legacy quotas in quota files.
+	 */
+	if (test_opt(sb, PRJQUOTA) && !ext4_has_feature_project(sb)) {
+		ext4_msg(sb, KERN_ERR, "Project quota feature not enabled. "
+			 "Cannot enable project quota enforcement.");
+		return 0;
+	}
+	usr_qf_name = get_qf_name(sb, sbi, USRQUOTA);
+	grp_qf_name = get_qf_name(sb, sbi, GRPQUOTA);
+	if (usr_qf_name || grp_qf_name) {
+		if (test_opt(sb, USRQUOTA) && usr_qf_name)
+			clear_opt(sb, USRQUOTA);
+
+		if (test_opt(sb, GRPQUOTA) && grp_qf_name)
+			clear_opt(sb, GRPQUOTA);
+
+		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
+			ext4_msg(sb, KERN_ERR, "old and new quota "
+					"format mixing");
+			return 0;
+		}
+
+		if (!sbi->s_jquota_fmt) {
+			ext4_msg(sb, KERN_ERR, "journaled quota format "
+					"not specified");
+			return 0;
+		}
+	}
+#endif
+	if (test_opt(sb, DIOREAD_NOLOCK)) {
+		int blocksize =
+			BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
+		if (blocksize < PAGE_SIZE)
+			ext4_msg(sb, KERN_WARNING, "Warning: mounting with an "
+				 "experimental mount option 'dioread_nolock' "
+				 "for blocksize < PAGE_SIZE");
+	}
+	return 1;
+}
+
+static inline void ext4_show_quota_options(struct seq_file *seq,
+					   struct super_block *sb)
+{
+#if defined(CONFIG_QUOTA)
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	char *usr_qf_name, *grp_qf_name;
+
+	if (sbi->s_jquota_fmt) {
+		char *fmtname = "";
+
+		switch (sbi->s_jquota_fmt) {
+		case QFMT_VFS_OLD:
+			fmtname = "vfsold";
+			break;
+		case QFMT_VFS_V0:
+			fmtname = "vfsv0";
+			break;
+		case QFMT_VFS_V1:
+			fmtname = "vfsv1";
+			break;
+		}
+		seq_printf(seq, ",jqfmt=%s", fmtname);
+	}
+
+	rcu_read_lock();
+	usr_qf_name = rcu_dereference(sbi->s_qf_names[USRQUOTA]);
+	grp_qf_name = rcu_dereference(sbi->s_qf_names[GRPQUOTA]);
+	if (usr_qf_name)
+		seq_show_option(seq, "usrjquota", usr_qf_name);
+	if (grp_qf_name)
+		seq_show_option(seq, "grpjquota", grp_qf_name);
+	rcu_read_unlock();
+#endif
+}
+
+static const char *token2str(int token)
+{
+	const struct match_token *t;
+
+	for (t = tokens; t->token != Opt_err; t++)
+		if (t->token == token && !strchr(t->pattern, '='))
+			break;
+	return t->pattern;
+}
+
+/*
+ * Show an option if
+ *  - it's set to a non-default value OR
+ *  - if the per-sb default is different from the global default
+ */
+static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
+			      int nodefs)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	int def_errors, def_mount_opt = sbi->s_def_mount_opt;
+	const struct mount_opts *m;
+	char sep = nodefs ? '\n' : ',';
+
+#define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
+#define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
+
+	if (sbi->s_sb_block != 1)
+		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
+
+	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
+		int want_set = m->flags & MOPT_SET;
+		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
+		    (m->flags & MOPT_CLEAR_ERR) || m->flags & MOPT_SKIP)
+			continue;
+		if (!nodefs && !(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
+			continue; /* skip if same as the default */
+		if ((want_set &&
+		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
+		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
+			continue; /* select Opt_noFoo vs Opt_Foo */
+		SEQ_OPTS_PRINT("%s", token2str(m->token));
+	}
+
+	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
+	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
+		SEQ_OPTS_PRINT("resuid=%u",
+				from_kuid_munged(&init_user_ns, sbi->s_resuid));
+	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
+	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
+		SEQ_OPTS_PRINT("resgid=%u",
+				from_kgid_munged(&init_user_ns, sbi->s_resgid));
+	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
+	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
+		SEQ_OPTS_PUTS("errors=remount-ro");
+	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
+		SEQ_OPTS_PUTS("errors=continue");
+	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
+		SEQ_OPTS_PUTS("errors=panic");
+	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
+		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
+	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
+		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
+	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
+		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
+	if (sb->s_flags & SB_I_VERSION)
+		SEQ_OPTS_PUTS("i_version");
+	if (nodefs || sbi->s_stripe)
+		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
+	if (nodefs || EXT4_MOUNT_DATA_FLAGS &
+			(sbi->s_mount_opt ^ def_mount_opt)) {
+		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
+			SEQ_OPTS_PUTS("data=journal");
+		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
+			SEQ_OPTS_PUTS("data=ordered");
+		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
+			SEQ_OPTS_PUTS("data=writeback");
+	}
+	if (nodefs ||
+	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
+		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
+			       sbi->s_inode_readahead_blks);
+
+	if (test_opt(sb, INIT_INODE_TABLE) && (nodefs ||
+		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
+		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
+	if (nodefs || sbi->s_max_dir_size_kb)
+		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
+	if (test_opt(sb, DATA_ERR_ABORT))
+		SEQ_OPTS_PUTS("data_err=abort");
+
+	fscrypt_show_test_dummy_encryption(seq, sep, sb);
+
+	if (sb->s_flags & SB_INLINECRYPT)
+		SEQ_OPTS_PUTS("inlinecrypt");
+
+	if (test_opt(sb, DAX_ALWAYS)) {
+		if (IS_EXT2_SB(sb))
+			SEQ_OPTS_PUTS("dax");
+		else
+			SEQ_OPTS_PUTS("dax=always");
+	} else if (test_opt2(sb, DAX_NEVER)) {
+		SEQ_OPTS_PUTS("dax=never");
+	} else if (test_opt2(sb, DAX_INODE)) {
+		SEQ_OPTS_PUTS("dax=inode");
+	}
+	ext4_show_quota_options(seq, sb);
+	return 0;
+}
+
+static int ext4_show_options(struct seq_file *seq, struct dentry *root)
+{
+	return _ext4_show_options(seq, root->d_sb, 0);
+}
+
+int ext4_seq_options_show(struct seq_file *seq, void *offset)
+{
+	struct super_block *sb = seq->private;
+	int rc;
+
+	seq_puts(seq, sb_rdonly(sb) ? "ro" : "rw");
+	rc = _ext4_show_options(seq, sb, 1);
+	seq_puts(seq, "\n");
+	return rc;
+}
+
+static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
+			    int read_only)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int err = 0;
+
+	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
+		ext4_msg(sb, KERN_ERR, "revision level too high, "
+			 "forcing read-only mode");
+		err = -EROFS;
+		goto done;
+	}
+	if (read_only)
+		goto done;
+	if (!(sbi->s_mount_state & EXT4_VALID_FS))
+		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
+			 "running e2fsck is recommended");
+	else if (sbi->s_mount_state & EXT4_ERROR_FS)
+		ext4_msg(sb, KERN_WARNING,
+			 "warning: mounting fs with errors, "
+			 "running e2fsck is recommended");
+	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
+		 le16_to_cpu(es->s_mnt_count) >=
+		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
+		ext4_msg(sb, KERN_WARNING,
+			 "warning: maximal mount count reached, "
+			 "running e2fsck is recommended");
+	else if (le32_to_cpu(es->s_checkinterval) &&
+		 (ext4_get_tstamp(es, s_lastcheck) +
+		  le32_to_cpu(es->s_checkinterval) <= ktime_get_real_seconds()))
+		ext4_msg(sb, KERN_WARNING,
+			 "warning: checktime reached, "
+			 "running e2fsck is recommended");
+	if (!sbi->s_journal)
+		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
+	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
+		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
+	le16_add_cpu(&es->s_mnt_count, 1);
+	ext4_update_tstamp(es, s_mtime);
+	if (sbi->s_journal)
+		ext4_set_feature_journal_needs_recovery(sb);
+
+	err = ext4_commit_super(sb, 1);
+done:
+	if (test_opt(sb, DEBUG))
+		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
+				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
+			sb->s_blocksize,
+			sbi->s_groups_count,
+			EXT4_BLOCKS_PER_GROUP(sb),
+			EXT4_INODES_PER_GROUP(sb),
+			sbi->s_mount_opt, sbi->s_mount_opt2);
+
+	cleancache_init_fs(sb);
+	return err;
+}
+
+int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct flex_groups **old_groups, **new_groups;
+	int size, i, j;
+
+	if (!sbi->s_log_groups_per_flex)
+		return 0;
+
+	size = ext4_flex_group(sbi, ngroup - 1) + 1;
+	if (size <= sbi->s_flex_groups_allocated)
+		return 0;
+
+	new_groups = kvzalloc(roundup_pow_of_two(size *
+			      sizeof(*sbi->s_flex_groups)), GFP_KERNEL);
+	if (!new_groups) {
+		ext4_msg(sb, KERN_ERR,
+			 "not enough memory for %d flex group pointers", size);
+		return -ENOMEM;
+	}
+	for (i = sbi->s_flex_groups_allocated; i < size; i++) {
+		new_groups[i] = kvzalloc(roundup_pow_of_two(
+					 sizeof(struct flex_groups)),
+					 GFP_KERNEL);
+		if (!new_groups[i]) {
+			for (j = sbi->s_flex_groups_allocated; j < i; j++)
+				kvfree(new_groups[j]);
+			kvfree(new_groups);
+			ext4_msg(sb, KERN_ERR,
+				 "not enough memory for %d flex groups", size);
+			return -ENOMEM;
+		}
+	}
+	rcu_read_lock();
+	old_groups = rcu_dereference(sbi->s_flex_groups);
+	if (old_groups)
+		memcpy(new_groups, old_groups,
+		       (sbi->s_flex_groups_allocated *
+			sizeof(struct flex_groups *)));
+	rcu_read_unlock();
+	rcu_assign_pointer(sbi->s_flex_groups, new_groups);
+	sbi->s_flex_groups_allocated = size;
+	if (old_groups)
+		ext4_kvfree_array_rcu(old_groups);
+	return 0;
+}
+
+static int ext4_fill_flex_info(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_desc *gdp = NULL;
+	struct flex_groups *fg;
+	ext4_group_t flex_group;
+	int i, err;
+
+	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
+	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
+		sbi->s_log_groups_per_flex = 0;
+		return 1;
+	}
+
+	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
+	if (err)
+		goto failed;
+
+	for (i = 0; i < sbi->s_groups_count; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+
+		flex_group = ext4_flex_group(sbi, i);
+		fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
+		atomic_add(ext4_free_inodes_count(sb, gdp), &fg->free_inodes);
+		atomic64_add(ext4_free_group_clusters(sb, gdp),
+			     &fg->free_clusters);
+		atomic_add(ext4_used_dirs_count(sb, gdp), &fg->used_dirs);
+	}
+
+	return 1;
+failed:
+	return 0;
+}
+
+static __le16 ext4_group_desc_csum(struct super_block *sb, __u32 block_group,
+				   struct ext4_group_desc *gdp)
+{
+	int offset = offsetof(struct ext4_group_desc, bg_checksum);
+	__u16 crc = 0;
+	__le32 le_group = cpu_to_le32(block_group);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (ext4_has_metadata_csum(sbi->s_sb)) {
+		/* Use new metadata_csum algorithm */
+		__u32 csum32;
+		__u16 dummy_csum = 0;
+
+		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
+				     sizeof(le_group));
+		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp, offset);
+		csum32 = ext4_chksum(sbi, csum32, (__u8 *)&dummy_csum,
+				     sizeof(dummy_csum));
+		offset += sizeof(dummy_csum);
+		if (offset < sbi->s_desc_size)
+			csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp + offset,
+					     sbi->s_desc_size - offset);
+
+		crc = csum32 & 0xFFFF;
+		goto out;
+	}
+
+	/* old crc16 code */
+	if (!ext4_has_feature_gdt_csum(sb))
+		return 0;
+
+	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
+	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
+	crc = crc16(crc, (__u8 *)gdp, offset);
+	offset += sizeof(gdp->bg_checksum); /* skip checksum */
+	/* for checksum of struct ext4_group_desc do the rest...*/
+	if (ext4_has_feature_64bit(sb) && offset < sbi->s_desc_size)
+		crc = crc16(crc, (__u8 *)gdp + offset,
+			    sbi->s_desc_size - offset);
+
+out:
+	return cpu_to_le16(crc);
+}
+
+int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
+				struct ext4_group_desc *gdp)
+{
+	if (ext4_has_group_desc_csum(sb) &&
+	    (gdp->bg_checksum != ext4_group_desc_csum(sb, block_group, gdp)))
+		return 0;
+
+	return 1;
+}
+
+void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
+			      struct ext4_group_desc *gdp)
+{
+	if (!ext4_has_group_desc_csum(sb))
+		return;
+	gdp->bg_checksum = ext4_group_desc_csum(sb, block_group, gdp);
+}
+
+/* Called at mount-time, super-block is locked */
+static int ext4_check_descriptors(struct super_block *sb,
+				  ext4_fsblk_t sb_block,
+				  ext4_group_t *first_not_zeroed)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
+	ext4_fsblk_t last_block;
+	ext4_fsblk_t last_bg_block = sb_block + ext4_bg_num_gdb(sb, 0);
+	ext4_fsblk_t block_bitmap;
+	ext4_fsblk_t inode_bitmap;
+	ext4_fsblk_t inode_table;
+	int flexbg_flag = 0;
+	ext4_group_t i, grp = sbi->s_groups_count;
+
+	if (ext4_has_feature_flex_bg(sb))
+		flexbg_flag = 1;
+
+	ext4_debug("Checking group descriptors");
+
+	for (i = 0; i < sbi->s_groups_count; i++) {
+		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
+
+		if (i == sbi->s_groups_count - 1 || flexbg_flag)
+			last_block = ext4_blocks_count(sbi->s_es) - 1;
+		else
+			last_block = first_block +
+				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
+
+		if ((grp == sbi->s_groups_count) &&
+		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
+			grp = i;
+
+		block_bitmap = ext4_block_bitmap(sb, gdp);
+		if (block_bitmap == sb_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+				 "Block bitmap for group %u overlaps "
+				 "superblock", i);
+			if (!sb_rdonly(sb))
+				return 0;
+		}
+		if (block_bitmap >= sb_block + 1 &&
+		    block_bitmap <= last_bg_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+				 "Block bitmap for group %u overlaps "
+				 "block group descriptors", i);
+			if (!sb_rdonly(sb))
+				return 0;
+		}
+		if (block_bitmap < first_block || block_bitmap > last_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+			       "Block bitmap for group %u not in group "
+			       "(block %llu)!", i, block_bitmap);
+			return 0;
+		}
+		inode_bitmap = ext4_inode_bitmap(sb, gdp);
+		if (inode_bitmap == sb_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+				 "Inode bitmap for group %u overlaps "
+				 "superblock", i);
+			if (!sb_rdonly(sb))
+				return 0;
+		}
+		if (inode_bitmap >= sb_block + 1 &&
+		    inode_bitmap <= last_bg_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+				 "Inode bitmap for group %u overlaps "
+				 "block group descriptors", i);
+			if (!sb_rdonly(sb))
+				return 0;
+		}
+		if (inode_bitmap < first_block || inode_bitmap > last_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+			       "Inode bitmap for group %u not in group "
+			       "(block %llu)!", i, inode_bitmap);
+			return 0;
+		}
+		inode_table = ext4_inode_table(sb, gdp);
+		if (inode_table == sb_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+				 "Inode table for group %u overlaps "
+				 "superblock", i);
+			if (!sb_rdonly(sb))
+				return 0;
+		}
+		if (inode_table >= sb_block + 1 &&
+		    inode_table <= last_bg_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+				 "Inode table for group %u overlaps "
+				 "block group descriptors", i);
+			if (!sb_rdonly(sb))
+				return 0;
+		}
+		if (inode_table < first_block ||
+		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+			       "Inode table for group %u not in group "
+			       "(block %llu)!", i, inode_table);
+			return 0;
+		}
+		ext4_lock_group(sb, i);
+		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
+			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
+				 "Checksum for group %u failed (%u!=%u)",
+				 i, le16_to_cpu(ext4_group_desc_csum(sb, i,
+				     gdp)), le16_to_cpu(gdp->bg_checksum));
+			if (!sb_rdonly(sb)) {
+				ext4_unlock_group(sb, i);
+				return 0;
+			}
+		}
+		ext4_unlock_group(sb, i);
+		if (!flexbg_flag)
+			first_block += EXT4_BLOCKS_PER_GROUP(sb);
+	}
+	if (NULL != first_not_zeroed)
+		*first_not_zeroed = grp;
+	return 1;
+}
+
+/* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
+ * the superblock) which were deleted from all directories, but held open by
+ * a process at the time of a crash.  We walk the list and try to delete these
+ * inodes at recovery time (only with a read-write filesystem).
+ *
+ * In order to keep the orphan inode chain consistent during traversal (in
+ * case of crash during recovery), we link each inode into the superblock
+ * orphan list_head and handle it the same way as an inode deletion during
+ * normal operation (which journals the operations for us).
+ *
+ * We only do an iget() and an iput() on each inode, which is very safe if we
+ * accidentally point at an in-use or already deleted inode.  The worst that
+ * can happen in this case is that we get a "bit already cleared" message from
+ * ext4_free_inode().  The only reason we would point at a wrong inode is if
+ * e2fsck was run on this filesystem, and it must have already done the orphan
+ * inode cleanup for us, so we can safely abort without any further action.
+ */
+static void ext4_orphan_cleanup(struct super_block *sb,
+				struct ext4_super_block *es)
+{
+	unsigned int s_flags = sb->s_flags;
+	int ret, nr_orphans = 0, nr_truncates = 0;
+#ifdef CONFIG_QUOTA
+	int quota_update = 0;
+	int i;
+#endif
+	if (!es->s_last_orphan) {
+		jbd_debug(4, "no orphan inodes to clean up\n");
+		return;
+	}
+
+	if (bdev_read_only(sb->s_bdev)) {
+		ext4_msg(sb, KERN_ERR, "write access "
+			"unavailable, skipping orphan cleanup");
+		return;
+	}
+
+	/* Check if feature set would not allow a r/w mount */
+	if (!ext4_feature_set_ok(sb, 0)) {
+		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
+			 "unknown ROCOMPAT features");
+		return;
+	}
+
+	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
+		/* don't clear list on RO mount w/ errors */
+		if (es->s_last_orphan && !(s_flags & SB_RDONLY)) {
+			ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
+				  "clearing orphan list.\n");
+			es->s_last_orphan = 0;
+		}
+		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
+		return;
+	}
+
+	if (s_flags & SB_RDONLY) {
+		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
+		sb->s_flags &= ~SB_RDONLY;
+	}
+#ifdef CONFIG_QUOTA
+	/*
+	 * Turn on quotas which were not enabled for read-only mounts if
+	 * filesystem has quota feature, so that they are updated correctly.
+	 */
+	if (ext4_has_feature_quota(sb) && (s_flags & SB_RDONLY)) {
+		int ret = ext4_enable_quotas(sb);
+
+		if (!ret)
+			quota_update = 1;
+		else
+			ext4_msg(sb, KERN_ERR,
+				"Cannot turn on quotas: error %d", ret);
+	}
+
+	/* Turn on journaled quotas used for old sytle */
+	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
+		if (EXT4_SB(sb)->s_qf_names[i]) {
+			int ret = ext4_quota_on_mount(sb, i);
+
+			if (!ret)
+				quota_update = 1;
+			else
+				ext4_msg(sb, KERN_ERR,
+					"Cannot turn on journaled "
+					"quota: type %d: error %d", i, ret);
+		}
+	}
+#endif
+
+	while (es->s_last_orphan) {
+		struct inode *inode;
+
+		/*
+		 * We may have encountered an error during cleanup; if
+		 * so, skip the rest.
+		 */
+		if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
+			jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
+			es->s_last_orphan = 0;
+			break;
+		}
+
+		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
+		if (IS_ERR(inode)) {
+			es->s_last_orphan = 0;
+			break;
+		}
+
+		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
+		dquot_initialize(inode);
+		if (inode->i_nlink) {
+			if (test_opt(sb, DEBUG))
+				ext4_msg(sb, KERN_DEBUG,
+					"%s: truncating inode %lu to %lld bytes",
+					__func__, inode->i_ino, inode->i_size);
+			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
+				  inode->i_ino, inode->i_size);
+			inode_lock(inode);
+			truncate_inode_pages(inode->i_mapping, inode->i_size);
+			ret = ext4_truncate(inode);
+			if (ret) {
+				/*
+				 * We need to clean up the in-core orphan list
+				 * manually if ext4_truncate() failed to get a
+				 * transaction handle.
+				 */
+				ext4_orphan_del(NULL, inode);
+				ext4_std_error(inode->i_sb, ret);
+			}
+			inode_unlock(inode);
+			nr_truncates++;
+		} else {
+			if (test_opt(sb, DEBUG))
+				ext4_msg(sb, KERN_DEBUG,
+					"%s: deleting unreferenced inode %lu",
+					__func__, inode->i_ino);
+			jbd_debug(2, "deleting unreferenced inode %lu\n",
+				  inode->i_ino);
+			nr_orphans++;
+		}
+		iput(inode);  /* The delete magic happens here! */
+	}
+
+#define PLURAL(x) (x), ((x) == 1) ? "" : "s"
+
+	if (nr_orphans)
+		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
+		       PLURAL(nr_orphans));
+	if (nr_truncates)
+		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
+		       PLURAL(nr_truncates));
+#ifdef CONFIG_QUOTA
+	/* Turn off quotas if they were enabled for orphan cleanup */
+	if (quota_update) {
+		for (i = 0; i < EXT4_MAXQUOTAS; i++) {
+			if (sb_dqopt(sb)->files[i])
+				dquot_quota_off(sb, i);
+		}
+	}
+#endif
+	sb->s_flags = s_flags; /* Restore SB_RDONLY status */
+}
+
+/*
+ * Maximal extent format file size.
+ * Resulting logical blkno at s_maxbytes must fit in our on-disk
+ * extent format containers, within a sector_t, and within i_blocks
+ * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
+ * so that won't be a limiting factor.
+ *
+ * However there is other limiting factor. We do store extents in the form
+ * of starting block and length, hence the resulting length of the extent
+ * covering maximum file size must fit into on-disk format containers as
+ * well. Given that length is always by 1 unit bigger than max unit (because
+ * we count 0 as well) we have to lower the s_maxbytes by one fs block.
+ *
+ * Note, this does *not* consider any metadata overhead for vfs i_blocks.
+ */
+static loff_t ext4_max_size(int blkbits, int has_huge_files)
+{
+	loff_t res;
+	loff_t upper_limit = MAX_LFS_FILESIZE;
+
+	BUILD_BUG_ON(sizeof(blkcnt_t) < sizeof(u64));
+
+	if (!has_huge_files) {
+		upper_limit = (1LL << 32) - 1;
+
+		/* total blocks in file system block size */
+		upper_limit >>= (blkbits - 9);
+		upper_limit <<= blkbits;
+	}
+
+	/*
+	 * 32-bit extent-start container, ee_block. We lower the maxbytes
+	 * by one fs block, so ee_len can cover the extent of maximum file
+	 * size
+	 */
+	res = (1LL << 32) - 1;
+	res <<= blkbits;
+
+	/* Sanity check against vm- & vfs- imposed limits */
+	if (res > upper_limit)
+		res = upper_limit;
+
+	return res;
+}
+
+/*
+ * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
+ * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
+ * We need to be 1 filesystem block less than the 2^48 sector limit.
+ */
+static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
+{
+	unsigned long long upper_limit, res = EXT4_NDIR_BLOCKS;
+	int meta_blocks;
+
+	/*
+	 * This is calculated to be the largest file size for a dense, block
+	 * mapped file such that the file's total number of 512-byte sectors,
+	 * including data and all indirect blocks, does not exceed (2^48 - 1).
+	 *
+	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
+	 * number of 512-byte sectors of the file.
+	 */
+	if (!has_huge_files) {
+		/*
+		 * !has_huge_files or implies that the inode i_block field
+		 * represents total file blocks in 2^32 512-byte sectors ==
+		 * size of vfs inode i_blocks * 8
+		 */
+		upper_limit = (1LL << 32) - 1;
+
+		/* total blocks in file system block size */
+		upper_limit >>= (bits - 9);
+
+	} else {
+		/*
+		 * We use 48 bit ext4_inode i_blocks
+		 * With EXT4_HUGE_FILE_FL set the i_blocks
+		 * represent total number of blocks in
+		 * file system block size
+		 */
+		upper_limit = (1LL << 48) - 1;
+
+	}
+
+	/* indirect blocks */
+	meta_blocks = 1;
+	/* double indirect blocks */
+	meta_blocks += 1 + (1LL << (bits-2));
+	/* tripple indirect blocks */
+	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
+
+	upper_limit -= meta_blocks;
+	upper_limit <<= bits;
+
+	res += 1LL << (bits-2);
+	res += 1LL << (2*(bits-2));
+	res += 1LL << (3*(bits-2));
+	res <<= bits;
+	if (res > upper_limit)
+		res = upper_limit;
+
+	if (res > MAX_LFS_FILESIZE)
+		res = MAX_LFS_FILESIZE;
+
+	return (loff_t)res;
+}
+
+static ext4_fsblk_t descriptor_loc(struct super_block *sb,
+				   ext4_fsblk_t logical_sb_block, int nr)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_group_t bg, first_meta_bg;
+	int has_super = 0;
+
+	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
+
+	if (!ext4_has_feature_meta_bg(sb) || nr < first_meta_bg)
+		return logical_sb_block + nr + 1;
+	bg = sbi->s_desc_per_block * nr;
+	if (ext4_bg_has_super(sb, bg))
+		has_super = 1;
+
+	/*
+	 * If we have a meta_bg fs with 1k blocks, group 0's GDT is at
+	 * block 2, not 1.  If s_first_data_block == 0 (bigalloc is enabled
+	 * on modern mke2fs or blksize > 1k on older mke2fs) then we must
+	 * compensate.
+	 */
+	if (sb->s_blocksize == 1024 && nr == 0 &&
+	    le32_to_cpu(sbi->s_es->s_first_data_block) == 0)
+		has_super++;
+
+	return (has_super + ext4_group_first_block_no(sb, bg));
+}
+
+/**
+ * ext4_get_stripe_size: Get the stripe size.
+ * @sbi: In memory super block info
+ *
+ * If we have specified it via mount option, then
+ * use the mount option value. If the value specified at mount time is
+ * greater than the blocks per group use the super block value.
+ * If the super block value is greater than blocks per group return 0.
+ * Allocator needs it be less than blocks per group.
+ *
+ */
+static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
+{
+	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
+	unsigned long stripe_width =
+			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
+	int ret;
+
+	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
+		ret = sbi->s_stripe;
+	else if (stripe_width && stripe_width <= sbi->s_blocks_per_group)
+		ret = stripe_width;
+	else if (stride && stride <= sbi->s_blocks_per_group)
+		ret = stride;
+	else
+		ret = 0;
+
+	/*
+	 * If the stripe width is 1, this makes no sense and
+	 * we set it to 0 to turn off stripe handling code.
+	 */
+	if (ret <= 1)
+		ret = 0;
+
+	return ret;
+}
+
+/*
+ * Check whether this filesystem can be mounted based on
+ * the features present and the RDONLY/RDWR mount requested.
+ * Returns 1 if this filesystem can be mounted as requested,
+ * 0 if it cannot be.
+ */
+static int ext4_feature_set_ok(struct super_block *sb, int readonly)
+{
+	if (ext4_has_unknown_ext4_incompat_features(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			"Couldn't mount because of "
+			"unsupported optional features (%x)",
+			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
+			~EXT4_FEATURE_INCOMPAT_SUPP));
+		return 0;
+	}
+
+#ifndef CONFIG_UNICODE
+	if (ext4_has_feature_casefold(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Filesystem with casefold feature cannot be "
+			 "mounted without CONFIG_UNICODE");
+		return 0;
+	}
+#endif
+
+	if (readonly)
+		return 1;
+
+	if (ext4_has_feature_readonly(sb)) {
+		ext4_msg(sb, KERN_INFO, "filesystem is read-only");
+		sb->s_flags |= SB_RDONLY;
+		return 1;
+	}
+
+	/* Check that feature set is OK for a read-write mount */
+	if (ext4_has_unknown_ext4_ro_compat_features(sb)) {
+		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
+			 "unsupported optional features (%x)",
+			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
+				~EXT4_FEATURE_RO_COMPAT_SUPP));
+		return 0;
+	}
+	if (ext4_has_feature_bigalloc(sb) && !ext4_has_feature_extents(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Can't support bigalloc feature without "
+			 "extents feature\n");
+		return 0;
+	}
+
+#if !IS_ENABLED(CONFIG_QUOTA) || !IS_ENABLED(CONFIG_QFMT_V2)
+	if (!readonly && (ext4_has_feature_quota(sb) ||
+			  ext4_has_feature_project(sb))) {
+		ext4_msg(sb, KERN_ERR,
+			 "The kernel was not built with CONFIG_QUOTA and CONFIG_QFMT_V2");
+		return 0;
+	}
+#endif  /* CONFIG_QUOTA */
+	return 1;
+}
+
+/*
+ * This function is called once a day if we have errors logged
+ * on the file system
+ */
+static void print_daily_error_info(struct timer_list *t)
+{
+	struct ext4_sb_info *sbi = from_timer(sbi, t, s_err_report);
+	struct super_block *sb = sbi->s_sb;
+	struct ext4_super_block *es = sbi->s_es;
+
+	if (es->s_error_count)
+		/* fsck newer than v1.41.13 is needed to clean this condition. */
+		ext4_msg(sb, KERN_NOTICE, "error count since last fsck: %u",
+			 le32_to_cpu(es->s_error_count));
+	if (es->s_first_error_time) {
+		printk(KERN_NOTICE "EXT4-fs (%s): initial error at time %llu: %.*s:%d",
+		       sb->s_id,
+		       ext4_get_tstamp(es, s_first_error_time),
+		       (int) sizeof(es->s_first_error_func),
+		       es->s_first_error_func,
+		       le32_to_cpu(es->s_first_error_line));
+		if (es->s_first_error_ino)
+			printk(KERN_CONT ": inode %u",
+			       le32_to_cpu(es->s_first_error_ino));
+		if (es->s_first_error_block)
+			printk(KERN_CONT ": block %llu", (unsigned long long)
+			       le64_to_cpu(es->s_first_error_block));
+		printk(KERN_CONT "\n");
+	}
+	if (es->s_last_error_time) {
+		printk(KERN_NOTICE "EXT4-fs (%s): last error at time %llu: %.*s:%d",
+		       sb->s_id,
+		       ext4_get_tstamp(es, s_last_error_time),
+		       (int) sizeof(es->s_last_error_func),
+		       es->s_last_error_func,
+		       le32_to_cpu(es->s_last_error_line));
+		if (es->s_last_error_ino)
+			printk(KERN_CONT ": inode %u",
+			       le32_to_cpu(es->s_last_error_ino));
+		if (es->s_last_error_block)
+			printk(KERN_CONT ": block %llu", (unsigned long long)
+			       le64_to_cpu(es->s_last_error_block));
+		printk(KERN_CONT "\n");
+	}
+	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
+}
+
+/* Find next suitable group and run ext4_init_inode_table */
+static int ext4_run_li_request(struct ext4_li_request *elr)
+{
+	struct ext4_group_desc *gdp = NULL;
+	struct super_block *sb = elr->lr_super;
+	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
+	ext4_group_t group = elr->lr_next_group;
+	unsigned int prefetch_ios = 0;
+	int ret = 0;
+	u64 start_time;
+
+	if (elr->lr_mode == EXT4_LI_MODE_PREFETCH_BBITMAP) {
+		elr->lr_next_group = ext4_mb_prefetch(sb, group,
+				EXT4_SB(sb)->s_mb_prefetch, &prefetch_ios);
+		if (prefetch_ios)
+			ext4_mb_prefetch_fini(sb, elr->lr_next_group,
+					      prefetch_ios);
+		trace_ext4_prefetch_bitmaps(sb, group, elr->lr_next_group,
+					    prefetch_ios);
+		if (group >= elr->lr_next_group) {
+			ret = 1;
+			if (elr->lr_first_not_zeroed != ngroups &&
+			    !sb_rdonly(sb) && test_opt(sb, INIT_INODE_TABLE)) {
+				elr->lr_next_group = elr->lr_first_not_zeroed;
+				elr->lr_mode = EXT4_LI_MODE_ITABLE;
+				ret = 0;
+			}
+		}
+		return ret;
+	}
+
+	for (; group < ngroups; group++) {
+		gdp = ext4_get_group_desc(sb, group, NULL);
+		if (!gdp) {
+			ret = 1;
+			break;
+		}
+
+		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
+			break;
+	}
+
+	if (group >= ngroups)
+		ret = 1;
+
+	if (!ret) {
+		start_time = ktime_get_real_ns();
+		ret = ext4_init_inode_table(sb, group,
+					    elr->lr_timeout ? 0 : 1);
+		trace_ext4_lazy_itable_init(sb, group);
+		if (elr->lr_timeout == 0) {
+			elr->lr_timeout = nsecs_to_jiffies((ktime_get_real_ns() - start_time) *
+				EXT4_SB(elr->lr_super)->s_li_wait_mult);
+		}
+		elr->lr_next_sched = jiffies + elr->lr_timeout;
+		elr->lr_next_group = group + 1;
+	}
+	return ret;
+}
+
+/*
+ * Remove lr_request from the list_request and free the
+ * request structure. Should be called with li_list_mtx held
+ */
+static void ext4_remove_li_request(struct ext4_li_request *elr)
+{
+	if (!elr)
+		return;
+
+	list_del(&elr->lr_request);
+	EXT4_SB(elr->lr_super)->s_li_request = NULL;
+	kfree(elr);
+}
+
+static void ext4_unregister_li_request(struct super_block *sb)
+{
+	mutex_lock(&ext4_li_mtx);
+	if (!ext4_li_info) {
+		mutex_unlock(&ext4_li_mtx);
+		return;
+	}
+
+	mutex_lock(&ext4_li_info->li_list_mtx);
+	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
+	mutex_unlock(&ext4_li_info->li_list_mtx);
+	mutex_unlock(&ext4_li_mtx);
+}
+
+static struct task_struct *ext4_lazyinit_task;
+
+/*
+ * This is the function where ext4lazyinit thread lives. It walks
+ * through the request list searching for next scheduled filesystem.
+ * When such a fs is found, run the lazy initialization request
+ * (ext4_rn_li_request) and keep track of the time spend in this
+ * function. Based on that time we compute next schedule time of
+ * the request. When walking through the list is complete, compute
+ * next waking time and put itself into sleep.
+ */
+static int ext4_lazyinit_thread(void *arg)
+{
+	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
+	struct list_head *pos, *n;
+	struct ext4_li_request *elr;
+	unsigned long next_wakeup, cur;
+
+	BUG_ON(NULL == eli);
+	set_freezable();
+
+cont_thread:
+	while (true) {
+		next_wakeup = MAX_JIFFY_OFFSET;
+
+		mutex_lock(&eli->li_list_mtx);
+		if (list_empty(&eli->li_request_list)) {
+			mutex_unlock(&eli->li_list_mtx);
+			goto exit_thread;
+		}
+		list_for_each_safe(pos, n, &eli->li_request_list) {
+			int err = 0;
+			int progress = 0;
+			elr = list_entry(pos, struct ext4_li_request,
+					 lr_request);
+
+			if (time_before(jiffies, elr->lr_next_sched)) {
+				if (time_before(elr->lr_next_sched, next_wakeup))
+					next_wakeup = elr->lr_next_sched;
+				continue;
+			}
+			if (down_read_trylock(&elr->lr_super->s_umount)) {
+				if (sb_start_write_trylock(elr->lr_super)) {
+					progress = 1;
+					/*
+					 * We hold sb->s_umount, sb can not
+					 * be removed from the list, it is
+					 * now safe to drop li_list_mtx
+					 */
+					mutex_unlock(&eli->li_list_mtx);
+					err = ext4_run_li_request(elr);
+					sb_end_write(elr->lr_super);
+					mutex_lock(&eli->li_list_mtx);
+					n = pos->next;
+				}
+				up_read((&elr->lr_super->s_umount));
+			}
+			/* error, remove the lazy_init job */
+			if (err) {
+				ext4_remove_li_request(elr);
+				continue;
+			}
+			if (!progress) {
+				elr->lr_next_sched = jiffies +
+					(prandom_u32()
+					 % (EXT4_DEF_LI_MAX_START_DELAY * HZ));
+			}
+			if (time_before(elr->lr_next_sched, next_wakeup))
+				next_wakeup = elr->lr_next_sched;
+		}
+		mutex_unlock(&eli->li_list_mtx);
+
+		try_to_freeze();
+
+		cur = jiffies;
+		if ((time_after_eq(cur, next_wakeup)) ||
+		    (MAX_JIFFY_OFFSET == next_wakeup)) {
+			cond_resched();
+			continue;
+		}
+
+		schedule_timeout_interruptible(next_wakeup - cur);
+
+		if (kthread_should_stop()) {
+			ext4_clear_request_list();
+			goto exit_thread;
+		}
+	}
+
+exit_thread:
+	/*
+	 * It looks like the request list is empty, but we need
+	 * to check it under the li_list_mtx lock, to prevent any
+	 * additions into it, and of course we should lock ext4_li_mtx
+	 * to atomically free the list and ext4_li_info, because at
+	 * this point another ext4 filesystem could be registering
+	 * new one.
+	 */
+	mutex_lock(&ext4_li_mtx);
+	mutex_lock(&eli->li_list_mtx);
+	if (!list_empty(&eli->li_request_list)) {
+		mutex_unlock(&eli->li_list_mtx);
+		mutex_unlock(&ext4_li_mtx);
+		goto cont_thread;
+	}
+	mutex_unlock(&eli->li_list_mtx);
+	kfree(ext4_li_info);
+	ext4_li_info = NULL;
+	mutex_unlock(&ext4_li_mtx);
+
+	return 0;
+}
+
+static void ext4_clear_request_list(void)
+{
+	struct list_head *pos, *n;
+	struct ext4_li_request *elr;
+
+	mutex_lock(&ext4_li_info->li_list_mtx);
+	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
+		elr = list_entry(pos, struct ext4_li_request,
+				 lr_request);
+		ext4_remove_li_request(elr);
+	}
+	mutex_unlock(&ext4_li_info->li_list_mtx);
+}
+
+static int ext4_run_lazyinit_thread(void)
+{
+	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
+					 ext4_li_info, "ext4lazyinit");
+	if (IS_ERR(ext4_lazyinit_task)) {
+		int err = PTR_ERR(ext4_lazyinit_task);
+		ext4_clear_request_list();
+		kfree(ext4_li_info);
+		ext4_li_info = NULL;
+		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
+				 "initialization thread\n",
+				 err);
+		return err;
+	}
+	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
+	return 0;
+}
+
+/*
+ * Check whether it make sense to run itable init. thread or not.
+ * If there is at least one uninitialized inode table, return
+ * corresponding group number, else the loop goes through all
+ * groups and return total number of groups.
+ */
+static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
+{
+	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
+	struct ext4_group_desc *gdp = NULL;
+
+	if (!ext4_has_group_desc_csum(sb))
+		return ngroups;
+
+	for (group = 0; group < ngroups; group++) {
+		gdp = ext4_get_group_desc(sb, group, NULL);
+		if (!gdp)
+			continue;
+
+		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
+			break;
+	}
+
+	return group;
+}
+
+static int ext4_li_info_new(void)
+{
+	struct ext4_lazy_init *eli = NULL;
+
+	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
+	if (!eli)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&eli->li_request_list);
+	mutex_init(&eli->li_list_mtx);
+
+	eli->li_state |= EXT4_LAZYINIT_QUIT;
+
+	ext4_li_info = eli;
+
+	return 0;
+}
+
+static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
+					    ext4_group_t start)
+{
+	struct ext4_li_request *elr;
+
+	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
+	if (!elr)
+		return NULL;
+
+	elr->lr_super = sb;
+	elr->lr_first_not_zeroed = start;
+	if (test_opt(sb, PREFETCH_BLOCK_BITMAPS))
+		elr->lr_mode = EXT4_LI_MODE_PREFETCH_BBITMAP;
+	else {
+		elr->lr_mode = EXT4_LI_MODE_ITABLE;
+		elr->lr_next_group = start;
+	}
+
+	/*
+	 * Randomize first schedule time of the request to
+	 * spread the inode table initialization requests
+	 * better.
+	 */
+	elr->lr_next_sched = jiffies + (prandom_u32() %
+				(EXT4_DEF_LI_MAX_START_DELAY * HZ));
+	return elr;
+}
+
+int ext4_register_li_request(struct super_block *sb,
+			     ext4_group_t first_not_zeroed)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_li_request *elr = NULL;
+	ext4_group_t ngroups = sbi->s_groups_count;
+	int ret = 0;
+
+	mutex_lock(&ext4_li_mtx);
+	if (sbi->s_li_request != NULL) {
+		/*
+		 * Reset timeout so it can be computed again, because
+		 * s_li_wait_mult might have changed.
+		 */
+		sbi->s_li_request->lr_timeout = 0;
+		goto out;
+	}
+
+	if (!test_opt(sb, PREFETCH_BLOCK_BITMAPS) &&
+	    (first_not_zeroed == ngroups || sb_rdonly(sb) ||
+	     !test_opt(sb, INIT_INODE_TABLE)))
+		goto out;
+
+	elr = ext4_li_request_new(sb, first_not_zeroed);
+	if (!elr) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (NULL == ext4_li_info) {
+		ret = ext4_li_info_new();
+		if (ret)
+			goto out;
+	}
+
+	mutex_lock(&ext4_li_info->li_list_mtx);
+	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
+	mutex_unlock(&ext4_li_info->li_list_mtx);
+
+	sbi->s_li_request = elr;
+	/*
+	 * set elr to NULL here since it has been inserted to
+	 * the request_list and the removal and free of it is
+	 * handled by ext4_clear_request_list from now on.
+	 */
+	elr = NULL;
+
+	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
+		ret = ext4_run_lazyinit_thread();
+		if (ret)
+			goto out;
+	}
+out:
+	mutex_unlock(&ext4_li_mtx);
+	if (ret)
+		kfree(elr);
+	return ret;
+}
+
+/*
+ * We do not need to lock anything since this is called on
+ * module unload.
+ */
+static void ext4_destroy_lazyinit_thread(void)
+{
+	/*
+	 * If thread exited earlier
+	 * there's nothing to be done.
+	 */
+	if (!ext4_li_info || !ext4_lazyinit_task)
+		return;
+
+	kthread_stop(ext4_lazyinit_task);
+}
+
+static int set_journal_csum_feature_set(struct super_block *sb)
+{
+	int ret = 1;
+	int compat, incompat;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (ext4_has_metadata_csum(sb)) {
+		/* journal checksum v3 */
+		compat = 0;
+		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
+	} else {
+		/* journal checksum v1 */
+		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
+		incompat = 0;
+	}
+
+	jbd2_journal_clear_features(sbi->s_journal,
+			JBD2_FEATURE_COMPAT_CHECKSUM, 0,
+			JBD2_FEATURE_INCOMPAT_CSUM_V3 |
+			JBD2_FEATURE_INCOMPAT_CSUM_V2);
+	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
+		ret = jbd2_journal_set_features(sbi->s_journal,
+				compat, 0,
+				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
+				incompat);
+	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
+		ret = jbd2_journal_set_features(sbi->s_journal,
+				compat, 0,
+				incompat);
+		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
+				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
+	} else {
+		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
+				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
+	}
+
+	return ret;
+}
+
+/*
+ * Note: calculating the overhead so we can be compatible with
+ * historical BSD practice is quite difficult in the face of
+ * clusters/bigalloc.  This is because multiple metadata blocks from
+ * different block group can end up in the same allocation cluster.
+ * Calculating the exact overhead in the face of clustered allocation
+ * requires either O(all block bitmaps) in memory or O(number of block
+ * groups**2) in time.  We will still calculate the superblock for
+ * older file systems --- and if we come across with a bigalloc file
+ * system with zero in s_overhead_clusters the estimate will be close to
+ * correct especially for very large cluster sizes --- but for newer
+ * file systems, it's better to calculate this figure once at mkfs
+ * time, and store it in the superblock.  If the superblock value is
+ * present (even for non-bigalloc file systems), we will use it.
+ */
+static int count_overhead(struct super_block *sb, ext4_group_t grp,
+			  char *buf)
+{
+	struct ext4_sb_info	*sbi = EXT4_SB(sb);
+	struct ext4_group_desc	*gdp;
+	ext4_fsblk_t		first_block, last_block, b;
+	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
+	int			s, j, count = 0;
+	int			has_super = ext4_bg_has_super(sb, grp);
+
+	if (!ext4_has_feature_bigalloc(sb))
+		return (has_super + ext4_bg_num_gdb(sb, grp) +
+			(has_super ? le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0) +
+			sbi->s_itb_per_group + 2);
+
+	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
+		(grp * EXT4_BLOCKS_PER_GROUP(sb));
+	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext4_get_group_desc(sb, i, NULL);
+		b = ext4_block_bitmap(sb, gdp);
+		if (b >= first_block && b <= last_block) {
+			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
+			count++;
+		}
+		b = ext4_inode_bitmap(sb, gdp);
+		if (b >= first_block && b <= last_block) {
+			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
+			count++;
+		}
+		b = ext4_inode_table(sb, gdp);
+		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
+			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
+				int c = EXT4_B2C(sbi, b - first_block);
+				ext4_set_bit(c, buf);
+				count++;
+			}
+		if (i != grp)
+			continue;
+		s = 0;
+		if (ext4_bg_has_super(sb, grp)) {
+			ext4_set_bit(s++, buf);
+			count++;
+		}
+		j = ext4_bg_num_gdb(sb, grp);
+		if (s + j > EXT4_BLOCKS_PER_GROUP(sb)) {
+			ext4_error(sb, "Invalid number of block group "
+				   "descriptor blocks: %d", j);
+			j = EXT4_BLOCKS_PER_GROUP(sb) - s;
+		}
+		count += j;
+		for (; j > 0; j--)
+			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
+	}
+	if (!count)
+		return 0;
+	return EXT4_CLUSTERS_PER_GROUP(sb) -
+		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
+}
+
+/*
+ * Compute the overhead and stash it in sbi->s_overhead
+ */
+int ext4_calculate_overhead(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct inode *j_inode;
+	unsigned int j_blocks, j_inum = le32_to_cpu(es->s_journal_inum);
+	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
+	ext4_fsblk_t overhead = 0;
+	char *buf = (char *) get_zeroed_page(GFP_NOFS);
+
+	if (!buf)
+		return -ENOMEM;
+
+	/*
+	 * Compute the overhead (FS structures).  This is constant
+	 * for a given filesystem unless the number of block groups
+	 * changes so we cache the previous value until it does.
+	 */
+
+	/*
+	 * All of the blocks before first_data_block are overhead
+	 */
+	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
+
+	/*
+	 * Add the overhead found in each block group
+	 */
+	for (i = 0; i < ngroups; i++) {
+		int blks;
+
+		blks = count_overhead(sb, i, buf);
+		overhead += blks;
+		if (blks)
+			memset(buf, 0, PAGE_SIZE);
+		cond_resched();
+	}
+
+	/*
+	 * Add the internal journal blocks whether the journal has been
+	 * loaded or not
+	 */
+	if (sbi->s_journal && !sbi->s_journal_bdev)
+		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_total_len);
+	else if (ext4_has_feature_journal(sb) && !sbi->s_journal && j_inum) {
+		/* j_inum for internal journal is non-zero */
+		j_inode = ext4_get_journal_inode(sb, j_inum);
+		if (j_inode) {
+			j_blocks = j_inode->i_size >> sb->s_blocksize_bits;
+			overhead += EXT4_NUM_B2C(sbi, j_blocks);
+			iput(j_inode);
+		} else {
+			ext4_msg(sb, KERN_ERR, "can't get journal size");
+		}
+	}
+	sbi->s_overhead = overhead;
+	smp_wmb();
+	free_page((unsigned long) buf);
+	return 0;
+}
+
+static void ext4_set_resv_clusters(struct super_block *sb)
+{
+	ext4_fsblk_t resv_clusters;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	/*
+	 * There's no need to reserve anything when we aren't using extents.
+	 * The space estimates are exact, there are no unwritten extents,
+	 * hole punching doesn't need new metadata... This is needed especially
+	 * to keep ext2/3 backward compatibility.
+	 */
+	if (!ext4_has_feature_extents(sb))
+		return;
+	/*
+	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
+	 * This should cover the situations where we can not afford to run
+	 * out of space like for example punch hole, or converting
+	 * unwritten extents in delalloc path. In most cases such
+	 * allocation would require 1, or 2 blocks, higher numbers are
+	 * very rare.
+	 */
+	resv_clusters = (ext4_blocks_count(sbi->s_es) >>
+			 sbi->s_cluster_bits);
+
+	do_div(resv_clusters, 50);
+	resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
+
+	atomic64_set(&sbi->s_resv_clusters, resv_clusters);
+}
+
+static int ext4_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
+	char *orig_data = kstrdup(data, GFP_KERNEL);
+	struct buffer_head *bh, **group_desc;
+	struct ext4_super_block *es = NULL;
+	struct ext4_sb_info *sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	struct flex_groups **flex_groups;
+	ext4_fsblk_t block;
+	ext4_fsblk_t sb_block = get_sb_block(&data);
+	ext4_fsblk_t logical_sb_block;
+	unsigned long offset = 0;
+	unsigned long journal_devnum = 0;
+	unsigned long def_mount_opts;
+	struct inode *root;
+	const char *descr;
+	int ret = -ENOMEM;
+	int blocksize, clustersize;
+	unsigned int db_count;
+	unsigned int i;
+	int needs_recovery, has_huge_files;
+	__u64 blocks_count;
+	int err = 0;
+	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
+	ext4_group_t first_not_zeroed;
+
+	if ((data && !orig_data) || !sbi)
+		goto out_free_base;
+
+	sbi->s_daxdev = dax_dev;
+	sbi->s_blockgroup_lock =
+		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
+	if (!sbi->s_blockgroup_lock)
+		goto out_free_base;
+
+	sb->s_fs_info = sbi;
+	sbi->s_sb = sb;
+	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
+	sbi->s_sb_block = sb_block;
+	if (sb->s_bdev->bd_part)
+		sbi->s_sectors_written_start =
+			part_stat_read(sb->s_bdev->bd_part, sectors[STAT_WRITE]);
+
+	/* Cleanup superblock name */
+	strreplace(sb->s_id, '/', '!');
+
+	/* -EINVAL is default */
+	ret = -EINVAL;
+	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
+	if (!blocksize) {
+		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
+		goto out_fail;
+	}
+
+	/*
+	 * The ext4 superblock will not be buffer aligned for other than 1kB
+	 * block sizes.  We need to calculate the offset from buffer start.
+	 */
+	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
+		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
+		offset = do_div(logical_sb_block, blocksize);
+	} else {
+		logical_sb_block = sb_block;
+	}
+
+	bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
+	if (IS_ERR(bh)) {
+		ext4_msg(sb, KERN_ERR, "unable to read superblock");
+		ret = PTR_ERR(bh);
+		bh = NULL;
+		goto out_fail;
+	}
+	/*
+	 * Note: s_es must be initialized as soon as possible because
+	 *       some ext4 macro-instructions depend on its value
+	 */
+	es = (struct ext4_super_block *) (bh->b_data + offset);
+	sbi->s_es = es;
+	sb->s_magic = le16_to_cpu(es->s_magic);
+	if (sb->s_magic != EXT4_SUPER_MAGIC)
+		goto cantfind_ext4;
+	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
+
+	/* Warn if metadata_csum and gdt_csum are both set. */
+	if (ext4_has_feature_metadata_csum(sb) &&
+	    ext4_has_feature_gdt_csum(sb))
+		ext4_warning(sb, "metadata_csum and uninit_bg are "
+			     "redundant flags; please run fsck.");
+
+	/* Check for a known checksum algorithm */
+	if (!ext4_verify_csum_type(sb, es)) {
+		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
+			 "unknown checksum algorithm.");
+		silent = 1;
+		goto cantfind_ext4;
+	}
+
+	/* Load the checksum driver */
+	sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
+	if (IS_ERR(sbi->s_chksum_driver)) {
+		ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
+		ret = PTR_ERR(sbi->s_chksum_driver);
+		sbi->s_chksum_driver = NULL;
+		goto failed_mount;
+	}
+
+	/* Check superblock checksum */
+	if (!ext4_superblock_csum_verify(sb, es)) {
+		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
+			 "invalid superblock checksum.  Run e2fsck?");
+		silent = 1;
+		ret = -EFSBADCRC;
+		goto cantfind_ext4;
+	}
+
+	/* Precompute checksum seed for all metadata */
+	if (ext4_has_feature_csum_seed(sb))
+		sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
+	else if (ext4_has_metadata_csum(sb) || ext4_has_feature_ea_inode(sb))
+		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
+					       sizeof(es->s_uuid));
+
+	/* Set defaults before we parse the mount options */
+	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+	set_opt(sb, INIT_INODE_TABLE);
+	if (def_mount_opts & EXT4_DEFM_DEBUG)
+		set_opt(sb, DEBUG);
+	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
+		set_opt(sb, GRPID);
+	if (def_mount_opts & EXT4_DEFM_UID16)
+		set_opt(sb, NO_UID32);
+	/* xattr user namespace & acls are now defaulted on */
+	set_opt(sb, XATTR_USER);
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+	set_opt(sb, POSIX_ACL);
+#endif
+	if (ext4_has_feature_fast_commit(sb))
+		set_opt2(sb, JOURNAL_FAST_COMMIT);
+	/* don't forget to enable journal_csum when metadata_csum is enabled. */
+	if (ext4_has_metadata_csum(sb))
+		set_opt(sb, JOURNAL_CHECKSUM);
+
+	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
+		set_opt(sb, JOURNAL_DATA);
+	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
+		set_opt(sb, ORDERED_DATA);
+	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
+		set_opt(sb, WRITEBACK_DATA);
+
+	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
+		set_opt(sb, ERRORS_PANIC);
+	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
+		set_opt(sb, ERRORS_CONT);
+	else
+		set_opt(sb, ERRORS_RO);
+	/* block_validity enabled by default; disable with noblock_validity */
+	set_opt(sb, BLOCK_VALIDITY);
+	if (def_mount_opts & EXT4_DEFM_DISCARD)
+		set_opt(sb, DISCARD);
+
+	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
+	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
+	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
+	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
+	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
+
+	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
+		set_opt(sb, BARRIER);
+
+	/*
+	 * enable delayed allocation by default
+	 * Use -o nodelalloc to turn it off
+	 */
+	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
+	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
+		set_opt(sb, DELALLOC);
+
+	/*
+	 * set default s_li_wait_mult for lazyinit, for the case there is
+	 * no mount option specified.
+	 */
+	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
+
+	if (le32_to_cpu(es->s_log_block_size) >
+	    (EXT4_MAX_BLOCK_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Invalid log block size: %u",
+			 le32_to_cpu(es->s_log_block_size));
+		goto failed_mount;
+	}
+	if (le32_to_cpu(es->s_log_cluster_size) >
+	    (EXT4_MAX_CLUSTER_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Invalid log cluster size: %u",
+			 le32_to_cpu(es->s_log_cluster_size));
+		goto failed_mount;
+	}
+
+	blocksize = EXT4_MIN_BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
+
+	if (blocksize == PAGE_SIZE)
+		set_opt(sb, DIOREAD_NOLOCK);
+
+	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
+		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
+		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
+	} else {
+		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
+		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
+		if (sbi->s_first_ino < EXT4_GOOD_OLD_FIRST_INO) {
+			ext4_msg(sb, KERN_ERR, "invalid first ino: %u",
+				 sbi->s_first_ino);
+			goto failed_mount;
+		}
+		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
+		    (!is_power_of_2(sbi->s_inode_size)) ||
+		    (sbi->s_inode_size > blocksize)) {
+			ext4_msg(sb, KERN_ERR,
+			       "unsupported inode size: %d",
+			       sbi->s_inode_size);
+			ext4_msg(sb, KERN_ERR, "blocksize: %d", blocksize);
+			goto failed_mount;
+		}
+		/*
+		 * i_atime_extra is the last extra field available for
+		 * [acm]times in struct ext4_inode. Checking for that
+		 * field should suffice to ensure we have extra space
+		 * for all three.
+		 */
+		if (sbi->s_inode_size >= offsetof(struct ext4_inode, i_atime_extra) +
+			sizeof(((struct ext4_inode *)0)->i_atime_extra)) {
+			sb->s_time_gran = 1;
+			sb->s_time_max = EXT4_EXTRA_TIMESTAMP_MAX;
+		} else {
+			sb->s_time_gran = NSEC_PER_SEC;
+			sb->s_time_max = EXT4_NON_EXTRA_TIMESTAMP_MAX;
+		}
+		sb->s_time_min = EXT4_TIMESTAMP_MIN;
+	}
+	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
+		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
+			EXT4_GOOD_OLD_INODE_SIZE;
+		if (ext4_has_feature_extra_isize(sb)) {
+			unsigned v, max = (sbi->s_inode_size -
+					   EXT4_GOOD_OLD_INODE_SIZE);
+
+			v = le16_to_cpu(es->s_want_extra_isize);
+			if (v > max) {
+				ext4_msg(sb, KERN_ERR,
+					 "bad s_want_extra_isize: %d", v);
+				goto failed_mount;
+			}
+			if (sbi->s_want_extra_isize < v)
+				sbi->s_want_extra_isize = v;
+
+			v = le16_to_cpu(es->s_min_extra_isize);
+			if (v > max) {
+				ext4_msg(sb, KERN_ERR,
+					 "bad s_min_extra_isize: %d", v);
+				goto failed_mount;
+			}
+			if (sbi->s_want_extra_isize < v)
+				sbi->s_want_extra_isize = v;
+		}
+	}
+
+	if (sbi->s_es->s_mount_opts[0]) {
+		char *s_mount_opts = kstrndup(sbi->s_es->s_mount_opts,
+					      sizeof(sbi->s_es->s_mount_opts),
+					      GFP_KERNEL);
+		if (!s_mount_opts)
+			goto failed_mount;
+		if (!parse_options(s_mount_opts, sb, &journal_devnum,
+				   &journal_ioprio, 0)) {
+			ext4_msg(sb, KERN_WARNING,
+				 "failed to parse options in superblock: %s",
+				 s_mount_opts);
+		}
+		kfree(s_mount_opts);
+	}
+	sbi->s_def_mount_opt = sbi->s_mount_opt;
+	if (!parse_options((char *) data, sb, &journal_devnum,
+			   &journal_ioprio, 0))
+		goto failed_mount;
+
+#ifdef CONFIG_UNICODE
+	if (ext4_has_feature_casefold(sb) && !sb->s_encoding) {
+		const struct ext4_sb_encodings *encoding_info;
+		struct unicode_map *encoding;
+		__u16 encoding_flags;
+
+		if (ext4_has_feature_encrypt(sb)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Can't mount with encoding and encryption");
+			goto failed_mount;
+		}
+
+		if (ext4_sb_read_encoding(es, &encoding_info,
+					  &encoding_flags)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Encoding requested by superblock is unknown");
+			goto failed_mount;
+		}
+
+		encoding = utf8_load(encoding_info->version);
+		if (IS_ERR(encoding)) {
+			ext4_msg(sb, KERN_ERR,
+				 "can't mount with superblock charset: %s-%s "
+				 "not supported by the kernel. flags: 0x%x.",
+				 encoding_info->name, encoding_info->version,
+				 encoding_flags);
+			goto failed_mount;
+		}
+		ext4_msg(sb, KERN_INFO,"Using encoding defined by superblock: "
+			 "%s-%s with flags 0x%hx", encoding_info->name,
+			 encoding_info->version?:"\b", encoding_flags);
+
+		sb->s_encoding = encoding;
+		sb->s_encoding_flags = encoding_flags;
+	}
+#endif
+
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
+		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting with data=journal disables delayed allocation, dioread_nolock, O_DIRECT and fast_commit support!\n");
+		/* can't mount with both data=journal and dioread_nolock. */
+		clear_opt(sb, DIOREAD_NOLOCK);
+		clear_opt2(sb, JOURNAL_FAST_COMMIT);
+		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "both data=journal and delalloc");
+			goto failed_mount;
+		}
+		if (test_opt(sb, DAX_ALWAYS)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "both data=journal and dax");
+			goto failed_mount;
+		}
+		if (ext4_has_feature_encrypt(sb)) {
+			ext4_msg(sb, KERN_WARNING,
+				 "encrypted files will use data=ordered "
+				 "instead of data journaling mode");
+		}
+		if (test_opt(sb, DELALLOC))
+			clear_opt(sb, DELALLOC);
+	} else {
+		sb->s_iflags |= SB_I_CGROUPWB;
+	}
+
+	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
+		(test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);
+
+	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
+	    (ext4_has_compat_features(sb) ||
+	     ext4_has_ro_compat_features(sb) ||
+	     ext4_has_incompat_features(sb)))
+		ext4_msg(sb, KERN_WARNING,
+		       "feature flags set on rev 0 fs, "
+		       "running e2fsck is recommended");
+
+	if (es->s_creator_os == cpu_to_le32(EXT4_OS_HURD)) {
+		set_opt2(sb, HURD_COMPAT);
+		if (ext4_has_feature_64bit(sb)) {
+			ext4_msg(sb, KERN_ERR,
+				 "The Hurd can't support 64-bit file systems");
+			goto failed_mount;
+		}
+
+		/*
+		 * ea_inode feature uses l_i_version field which is not
+		 * available in HURD_COMPAT mode.
+		 */
+		if (ext4_has_feature_ea_inode(sb)) {
+			ext4_msg(sb, KERN_ERR,
+				 "ea_inode feature is not supported for Hurd");
+			goto failed_mount;
+		}
+	}
+
+	if (IS_EXT2_SB(sb)) {
+		if (ext2_feature_set_ok(sb))
+			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
+				 "using the ext4 subsystem");
+		else {
+			/*
+			 * If we're probing be silent, if this looks like
+			 * it's actually an ext[34] filesystem.
+			 */
+			if (silent && ext4_feature_set_ok(sb, sb_rdonly(sb)))
+				goto failed_mount;
+			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
+				 "to feature incompatibilities");
+			goto failed_mount;
+		}
+	}
+
+	if (IS_EXT3_SB(sb)) {
+		if (ext3_feature_set_ok(sb))
+			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
+				 "using the ext4 subsystem");
+		else {
+			/*
+			 * If we're probing be silent, if this looks like
+			 * it's actually an ext4 filesystem.
+			 */
+			if (silent && ext4_feature_set_ok(sb, sb_rdonly(sb)))
+				goto failed_mount;
+			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
+				 "to feature incompatibilities");
+			goto failed_mount;
+		}
+	}
+
+	/*
+	 * Check feature flags regardless of the revision level, since we
+	 * previously didn't change the revision level when setting the flags,
+	 * so there is a chance incompat flags are set on a rev 0 filesystem.
+	 */
+	if (!ext4_feature_set_ok(sb, (sb_rdonly(sb))))
+		goto failed_mount;
+
+	if (le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) > (blocksize / 4)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Number of reserved GDT blocks insanely large: %d",
+			 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks));
+		goto failed_mount;
+	}
+
+	if (bdev_dax_supported(sb->s_bdev, blocksize))
+		set_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags);
+
+	if (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) {
+		if (ext4_has_feature_inline_data(sb)) {
+			ext4_msg(sb, KERN_ERR, "Cannot use DAX on a filesystem"
+					" that may contain inline data");
+			goto failed_mount;
+		}
+		if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags)) {
+			ext4_msg(sb, KERN_ERR,
+				"DAX unsupported by block device.");
+			goto failed_mount;
+		}
+	}
+
+	if (ext4_has_feature_encrypt(sb) && es->s_encryption_level) {
+		ext4_msg(sb, KERN_ERR, "Unsupported encryption level %d",
+			 es->s_encryption_level);
+		goto failed_mount;
+	}
+
+	if (sb->s_blocksize != blocksize) {
+		/*
+		 * bh must be released before kill_bdev(), otherwise
+		 * it won't be freed and its page also. kill_bdev()
+		 * is called by sb_set_blocksize().
+		 */
+		brelse(bh);
+		/* Validate the filesystem blocksize */
+		if (!sb_set_blocksize(sb, blocksize)) {
+			ext4_msg(sb, KERN_ERR, "bad block size %d",
+					blocksize);
+			bh = NULL;
+			goto failed_mount;
+		}
+
+		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
+		offset = do_div(logical_sb_block, blocksize);
+		bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
+		if (IS_ERR(bh)) {
+			ext4_msg(sb, KERN_ERR,
+			       "Can't read superblock on 2nd try");
+			ret = PTR_ERR(bh);
+			bh = NULL;
+			goto failed_mount;
+		}
+		es = (struct ext4_super_block *)(bh->b_data + offset);
+		sbi->s_es = es;
+		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
+			ext4_msg(sb, KERN_ERR,
+			       "Magic mismatch, very weird!");
+			goto failed_mount;
+		}
+	}
+
+	has_huge_files = ext4_has_feature_huge_file(sb);
+	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
+						      has_huge_files);
+	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
+
+	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
+	if (ext4_has_feature_64bit(sb)) {
+		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
+		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
+		    !is_power_of_2(sbi->s_desc_size)) {
+			ext4_msg(sb, KERN_ERR,
+			       "unsupported descriptor size %lu",
+			       sbi->s_desc_size);
+			goto failed_mount;
+		}
+	} else
+		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
+
+	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
+	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
+
+	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
+	if (sbi->s_inodes_per_block == 0)
+		goto cantfind_ext4;
+	if (sbi->s_inodes_per_group < sbi->s_inodes_per_block ||
+	    sbi->s_inodes_per_group > blocksize * 8) {
+		ext4_msg(sb, KERN_ERR, "invalid inodes per group: %lu\n",
+			 sbi->s_inodes_per_group);
+		goto failed_mount;
+	}
+	sbi->s_itb_per_group = sbi->s_inodes_per_group /
+					sbi->s_inodes_per_block;
+	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
+	sbi->s_sbh = bh;
+	sbi->s_mount_state = le16_to_cpu(es->s_state) & ~EXT4_FC_REPLAY;
+	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
+	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
+
+	for (i = 0; i < 4; i++)
+		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
+	sbi->s_def_hash_version = es->s_def_hash_version;
+	if (ext4_has_feature_dir_index(sb)) {
+		i = le32_to_cpu(es->s_flags);
+		if (i & EXT2_FLAGS_UNSIGNED_HASH)
+			sbi->s_hash_unsigned = 3;
+		else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
+#ifdef __CHAR_UNSIGNED__
+			if (!sb_rdonly(sb))
+				es->s_flags |=
+					cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
+			sbi->s_hash_unsigned = 3;
+#else
+			if (!sb_rdonly(sb))
+				es->s_flags |=
+					cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
+#endif
+		}
+	}
+
+	/* Handle clustersize */
+	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
+	if (ext4_has_feature_bigalloc(sb)) {
+		if (clustersize < blocksize) {
+			ext4_msg(sb, KERN_ERR,
+				 "cluster size (%d) smaller than "
+				 "block size (%d)", clustersize, blocksize);
+			goto failed_mount;
+		}
+		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
+			le32_to_cpu(es->s_log_block_size);
+		sbi->s_clusters_per_group =
+			le32_to_cpu(es->s_clusters_per_group);
+		if (sbi->s_clusters_per_group > blocksize * 8) {
+			ext4_msg(sb, KERN_ERR,
+				 "#clusters per group too big: %lu",
+				 sbi->s_clusters_per_group);
+			goto failed_mount;
+		}
+		if (sbi->s_blocks_per_group !=
+		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
+			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
+				 "clusters per group (%lu) inconsistent",
+				 sbi->s_blocks_per_group,
+				 sbi->s_clusters_per_group);
+			goto failed_mount;
+		}
+	} else {
+		if (clustersize != blocksize) {
+			ext4_msg(sb, KERN_ERR,
+				 "fragment/cluster size (%d) != "
+				 "block size (%d)", clustersize, blocksize);
+			goto failed_mount;
+		}
+		if (sbi->s_blocks_per_group > blocksize * 8) {
+			ext4_msg(sb, KERN_ERR,
+				 "#blocks per group too big: %lu",
+				 sbi->s_blocks_per_group);
+			goto failed_mount;
+		}
+		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
+		sbi->s_cluster_bits = 0;
+	}
+	sbi->s_cluster_ratio = clustersize / blocksize;
+
+	/* Do we have standard group size of clustersize * 8 blocks ? */
+	if (sbi->s_blocks_per_group == clustersize << 3)
+		set_opt2(sb, STD_GROUP_SIZE);
+
+	/*
+	 * Test whether we have more sectors than will fit in sector_t,
+	 * and whether the max offset is addressable by the page cache.
+	 */
+	err = generic_check_addressable(sb->s_blocksize_bits,
+					ext4_blocks_count(es));
+	if (err) {
+		ext4_msg(sb, KERN_ERR, "filesystem"
+			 " too large to mount safely on this system");
+		goto failed_mount;
+	}
+
+	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
+		goto cantfind_ext4;
+
+	/* check blocks count against device size */
+	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
+	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
+		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
+		       "exceeds size of device (%llu blocks)",
+		       ext4_blocks_count(es), blocks_count);
+		goto failed_mount;
+	}
+
+	/*
+	 * It makes no sense for the first data block to be beyond the end
+	 * of the filesystem.
+	 */
+	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
+		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
+			 "block %u is beyond end of filesystem (%llu)",
+			 le32_to_cpu(es->s_first_data_block),
+			 ext4_blocks_count(es));
+		goto failed_mount;
+	}
+	if ((es->s_first_data_block == 0) && (es->s_log_block_size == 0) &&
+	    (sbi->s_cluster_ratio == 1)) {
+		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
+			 "block is 0 with a 1k block and cluster size");
+		goto failed_mount;
+	}
+
+	blocks_count = (ext4_blocks_count(es) -
+			le32_to_cpu(es->s_first_data_block) +
+			EXT4_BLOCKS_PER_GROUP(sb) - 1);
+	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
+	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
+		ext4_msg(sb, KERN_WARNING, "groups count too large: %llu "
+		       "(block count %llu, first data block %u, "
+		       "blocks per group %lu)", blocks_count,
+		       ext4_blocks_count(es),
+		       le32_to_cpu(es->s_first_data_block),
+		       EXT4_BLOCKS_PER_GROUP(sb));
+		goto failed_mount;
+	}
+	sbi->s_groups_count = blocks_count;
+	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
+			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
+	if (((u64)sbi->s_groups_count * sbi->s_inodes_per_group) !=
+	    le32_to_cpu(es->s_inodes_count)) {
+		ext4_msg(sb, KERN_ERR, "inodes count not valid: %u vs %llu",
+			 le32_to_cpu(es->s_inodes_count),
+			 ((u64)sbi->s_groups_count * sbi->s_inodes_per_group));
+		ret = -EINVAL;
+		goto failed_mount;
+	}
+	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
+		   EXT4_DESC_PER_BLOCK(sb);
+	if (ext4_has_feature_meta_bg(sb)) {
+		if (le32_to_cpu(es->s_first_meta_bg) > db_count) {
+			ext4_msg(sb, KERN_WARNING,
+				 "first meta block group too large: %u "
+				 "(group descriptor block count %u)",
+				 le32_to_cpu(es->s_first_meta_bg), db_count);
+			goto failed_mount;
+		}
+	}
+	rcu_assign_pointer(sbi->s_group_desc,
+			   kvmalloc_array(db_count,
+					  sizeof(struct buffer_head *),
+					  GFP_KERNEL));
+	if (sbi->s_group_desc == NULL) {
+		ext4_msg(sb, KERN_ERR, "not enough memory");
+		ret = -ENOMEM;
+		goto failed_mount;
+	}
+
+	bgl_lock_init(sbi->s_blockgroup_lock);
+
+	/* Pre-read the descriptors into the buffer cache */
+	for (i = 0; i < db_count; i++) {
+		block = descriptor_loc(sb, logical_sb_block, i);
+		ext4_sb_breadahead_unmovable(sb, block);
+	}
+
+	for (i = 0; i < db_count; i++) {
+		struct buffer_head *bh;
+
+		block = descriptor_loc(sb, logical_sb_block, i);
+		bh = ext4_sb_bread_unmovable(sb, block);
+		if (IS_ERR(bh)) {
+			ext4_msg(sb, KERN_ERR,
+			       "can't read group descriptor %d", i);
+			db_count = i;
+			ret = PTR_ERR(bh);
+			bh = NULL;
+			goto failed_mount2;
+		}
+		rcu_read_lock();
+		rcu_dereference(sbi->s_group_desc)[i] = bh;
+		rcu_read_unlock();
+	}
+	sbi->s_gdb_count = db_count;
+	if (!ext4_check_descriptors(sb, logical_sb_block, &first_not_zeroed)) {
+		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
+		ret = -EFSCORRUPTED;
+		goto failed_mount2;
+	}
+
+	timer_setup(&sbi->s_err_report, print_daily_error_info, 0);
+
+	/* Register extent status tree shrinker */
+	if (ext4_es_register_shrinker(sbi))
+		goto failed_mount3;
+
+	sbi->s_stripe = ext4_get_stripe_size(sbi);
+	sbi->s_extent_max_zeroout_kb = 32;
+
+	/*
+	 * set up enough so that it can read an inode
+	 */
+	sb->s_op = &ext4_sops;
+	sb->s_export_op = &ext4_export_ops;
+	sb->s_xattr = ext4_xattr_handlers;
+#ifdef CONFIG_FS_ENCRYPTION
+	sb->s_cop = &ext4_cryptops;
+#endif
+#ifdef CONFIG_FS_VERITY
+	sb->s_vop = &ext4_verityops;
+#endif
+#ifdef CONFIG_QUOTA
+	sb->dq_op = &ext4_quota_operations;
+	if (ext4_has_feature_quota(sb))
+		sb->s_qcop = &dquot_quotactl_sysfile_ops;
+	else
+		sb->s_qcop = &ext4_qctl_operations;
+	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
+#endif
+	memcpy(&sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
+
+	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
+	mutex_init(&sbi->s_orphan_lock);
+
+	/* Initialize fast commit stuff */
+	atomic_set(&sbi->s_fc_subtid, 0);
+	atomic_set(&sbi->s_fc_ineligible_updates, 0);
+	INIT_LIST_HEAD(&sbi->s_fc_q[FC_Q_MAIN]);
+	INIT_LIST_HEAD(&sbi->s_fc_q[FC_Q_STAGING]);
+	INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_MAIN]);
+	INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_STAGING]);
+	sbi->s_fc_bytes = 0;
+	ext4_clear_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
+	ext4_clear_mount_flag(sb, EXT4_MF_FC_COMMITTING);
+	spin_lock_init(&sbi->s_fc_lock);
+	memset(&sbi->s_fc_stats, 0, sizeof(sbi->s_fc_stats));
+	sbi->s_fc_replay_state.fc_regions = NULL;
+	sbi->s_fc_replay_state.fc_regions_size = 0;
+	sbi->s_fc_replay_state.fc_regions_used = 0;
+	sbi->s_fc_replay_state.fc_regions_valid = 0;
+	sbi->s_fc_replay_state.fc_modified_inodes = NULL;
+	sbi->s_fc_replay_state.fc_modified_inodes_size = 0;
+	sbi->s_fc_replay_state.fc_modified_inodes_used = 0;
+
+	sb->s_root = NULL;
+
+	needs_recovery = (es->s_last_orphan != 0 ||
+			  ext4_has_feature_journal_needs_recovery(sb));
+
+	if (ext4_has_feature_mmp(sb) && !sb_rdonly(sb)) {
+		err = ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block));
+		if (err)
+			goto failed_mount3a;
+	}
+
+	/*
+	 * The first inode we look at is the journal inode.  Don't try
+	 * root first: it may be modified in the journal!
+	 */
+	if (!test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb)) {
+		err = ext4_load_journal(sb, es, journal_devnum);
+		if (err)
+			goto failed_mount3a;
+	} else if (test_opt(sb, NOLOAD) && !sb_rdonly(sb) &&
+		   ext4_has_feature_journal_needs_recovery(sb)) {
+		ext4_msg(sb, KERN_ERR, "required journal recovery "
+		       "suppressed and not mounted read-only");
+		goto failed_mount3a;
+	} else {
+		/* Nojournal mode, all journal mount options are illegal */
+		if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "journal_async_commit, fs mounted w/o journal");
+			goto failed_mount3a;
+		}
+
+		if (test_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "journal_checksum, fs mounted w/o journal");
+			goto failed_mount3a;
+		}
+		if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "commit=%lu, fs mounted w/o journal",
+				 sbi->s_commit_interval / HZ);
+			goto failed_mount3a;
+		}
+		if (EXT4_MOUNT_DATA_FLAGS &
+		    (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "data=, fs mounted w/o journal");
+			goto failed_mount3a;
+		}
+		sbi->s_def_mount_opt &= ~EXT4_MOUNT_JOURNAL_CHECKSUM;
+		clear_opt(sb, JOURNAL_CHECKSUM);
+		clear_opt(sb, DATA_FLAGS);
+		clear_opt2(sb, JOURNAL_FAST_COMMIT);
+		sbi->s_journal = NULL;
+		needs_recovery = 0;
+		goto no_journal;
+	}
+
+	if (ext4_has_feature_64bit(sb) &&
+	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
+				       JBD2_FEATURE_INCOMPAT_64BIT)) {
+		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
+		goto failed_mount_wq;
+	}
+
+	if (!set_journal_csum_feature_set(sb)) {
+		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
+			 "feature set");
+		goto failed_mount_wq;
+	}
+
+	if (test_opt2(sb, JOURNAL_FAST_COMMIT) &&
+		!jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
+					  JBD2_FEATURE_INCOMPAT_FAST_COMMIT)) {
+		ext4_msg(sb, KERN_ERR,
+			"Failed to set fast commit journal feature");
+		goto failed_mount_wq;
+	}
+
+	/* We have now updated the journal if required, so we can
+	 * validate the data journaling mode. */
+	switch (test_opt(sb, DATA_FLAGS)) {
+	case 0:
+		/* No mode set, assume a default based on the journal
+		 * capabilities: ORDERED_DATA if the journal can
+		 * cope, else JOURNAL_DATA
+		 */
+		if (jbd2_journal_check_available_features
+		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
+			set_opt(sb, ORDERED_DATA);
+			sbi->s_def_mount_opt |= EXT4_MOUNT_ORDERED_DATA;
+		} else {
+			set_opt(sb, JOURNAL_DATA);
+			sbi->s_def_mount_opt |= EXT4_MOUNT_JOURNAL_DATA;
+		}
+		break;
+
+	case EXT4_MOUNT_ORDERED_DATA:
+	case EXT4_MOUNT_WRITEBACK_DATA:
+		if (!jbd2_journal_check_available_features
+		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
+			ext4_msg(sb, KERN_ERR, "Journal does not support "
+			       "requested data journaling mode");
+			goto failed_mount_wq;
+		}
+	default:
+		break;
+	}
+
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA &&
+	    test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
+		ext4_msg(sb, KERN_ERR, "can't mount with "
+			"journal_async_commit in data=ordered mode");
+		goto failed_mount_wq;
+	}
+
+	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
+
+	sbi->s_journal->j_submit_inode_data_buffers =
+		ext4_journal_submit_inode_data_buffers;
+	sbi->s_journal->j_finish_inode_data_buffers =
+		ext4_journal_finish_inode_data_buffers;
+
+no_journal:
+	if (!test_opt(sb, NO_MBCACHE)) {
+		sbi->s_ea_block_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_block_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create ea_block_cache");
+			goto failed_mount_wq;
+		}
+
+		if (ext4_has_feature_ea_inode(sb)) {
+			sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+			if (!sbi->s_ea_inode_cache) {
+				ext4_msg(sb, KERN_ERR,
+					 "Failed to create ea_inode_cache");
+				goto failed_mount_wq;
+			}
+		}
+	}
+
+	if (ext4_has_feature_verity(sb) && blocksize != PAGE_SIZE) {
+		ext4_msg(sb, KERN_ERR, "Unsupported blocksize for fs-verity");
+		goto failed_mount_wq;
+	}
+
+	/*
+	 * Get the # of file system overhead blocks from the
+	 * superblock if present.
+	 */
+	sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
+	/* ignore the precalculated value if it is ridiculous */
+	if (sbi->s_overhead > ext4_blocks_count(es))
+		sbi->s_overhead = 0;
+	/*
+	 * If the bigalloc feature is not enabled recalculating the
+	 * overhead doesn't take long, so we might as well just redo
+	 * it to make sure we are using the correct value.
+	 */
+	if (!ext4_has_feature_bigalloc(sb))
+		sbi->s_overhead = 0;
+	if (sbi->s_overhead == 0) {
+		err = ext4_calculate_overhead(sb);
+		if (err)
+			goto failed_mount_wq;
+	}
+
+	/*
+	 * The maximum number of concurrent works can be high and
+	 * concurrency isn't really necessary.  Limit it to 1.
+	 */
+	EXT4_SB(sb)->rsv_conversion_wq =
+		alloc_workqueue("ext4-rsv-conversion", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
+	if (!EXT4_SB(sb)->rsv_conversion_wq) {
+		printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
+		ret = -ENOMEM;
+		goto failed_mount4;
+	}
+
+	/*
+	 * The jbd2_journal_load will have done any necessary log recovery,
+	 * so we can safely mount the rest of the filesystem now.
+	 */
+
+	root = ext4_iget(sb, EXT4_ROOT_INO, EXT4_IGET_SPECIAL);
+	if (IS_ERR(root)) {
+		ext4_msg(sb, KERN_ERR, "get root inode failed");
+		ret = PTR_ERR(root);
+		root = NULL;
+		goto failed_mount4;
+	}
+	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
+		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
+		iput(root);
+		goto failed_mount4;
+	}
+
+#ifdef CONFIG_UNICODE
+	if (sb->s_encoding)
+		sb->s_d_op = &ext4_dentry_ops;
+#endif
+
+	sb->s_root = d_make_root(root);
+	if (!sb->s_root) {
+		ext4_msg(sb, KERN_ERR, "get root dentry failed");
+		ret = -ENOMEM;
+		goto failed_mount4;
+	}
+
+	ret = ext4_setup_super(sb, es, sb_rdonly(sb));
+	if (ret == -EROFS) {
+		sb->s_flags |= SB_RDONLY;
+		ret = 0;
+	} else if (ret)
+		goto failed_mount4a;
+
+	ext4_set_resv_clusters(sb);
+
+	if (test_opt(sb, BLOCK_VALIDITY)) {
+		err = ext4_setup_system_zone(sb);
+		if (err) {
+			ext4_msg(sb, KERN_ERR, "failed to initialize system "
+				 "zone (%d)", err);
+			goto failed_mount4a;
+		}
+	}
+	ext4_fc_replay_cleanup(sb);
+
+	ext4_ext_init(sb);
+	err = ext4_mb_init(sb);
+	if (err) {
+		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
+			 err);
+		goto failed_mount5;
+	}
+
+	/*
+	 * We can only set up the journal commit callback once
+	 * mballoc is initialized
+	 */
+	if (sbi->s_journal)
+		sbi->s_journal->j_commit_callback =
+			ext4_journal_commit_callback;
+
+	block = ext4_count_free_clusters(sb);
+	ext4_free_blocks_count_set(sbi->s_es, 
+				   EXT4_C2B(sbi, block));
+	ext4_superblock_csum_set(sb);
+	err = percpu_counter_init(&sbi->s_freeclusters_counter, block,
+				  GFP_KERNEL);
+	if (!err) {
+		unsigned long freei = ext4_count_free_inodes(sb);
+		sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
+		ext4_superblock_csum_set(sb);
+		err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
+					  GFP_KERNEL);
+	}
+	if (!err)
+		err = percpu_counter_init(&sbi->s_dirs_counter,
+					  ext4_count_dirs(sb), GFP_KERNEL);
+	if (!err)
+		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
+					  GFP_KERNEL);
+	if (!err)
+		err = percpu_counter_init(&sbi->s_sra_exceeded_retry_limit, 0,
+					  GFP_KERNEL);
+	if (!err)
+		err = percpu_init_rwsem(&sbi->s_writepages_rwsem);
+
+	if (err) {
+		ext4_msg(sb, KERN_ERR, "insufficient memory");
+		goto failed_mount6;
+	}
+
+	if (ext4_has_feature_flex_bg(sb))
+		if (!ext4_fill_flex_info(sb)) {
+			ext4_msg(sb, KERN_ERR,
+			       "unable to initialize "
+			       "flex_bg meta info!");
+			ret = -ENOMEM;
+			goto failed_mount6;
+		}
+
+	err = ext4_register_li_request(sb, first_not_zeroed);
+	if (err)
+		goto failed_mount6;
+
+	err = ext4_register_sysfs(sb);
+	if (err)
+		goto failed_mount7;
+
+#ifdef CONFIG_QUOTA
+	/* Enable quota usage during mount. */
+	if (ext4_has_feature_quota(sb) && !sb_rdonly(sb)) {
+		err = ext4_enable_quotas(sb);
+		if (err)
+			goto failed_mount8;
+	}
+#endif  /* CONFIG_QUOTA */
+
+	/*
+	 * Save the original bdev mapping's wb_err value which could be
+	 * used to detect the metadata async write error.
+	 */
+	spin_lock_init(&sbi->s_bdev_wb_lock);
+	errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
+				 &sbi->s_bdev_wb_err);
+	sb->s_bdev->bd_super = sb;
+	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
+	ext4_orphan_cleanup(sb, es);
+	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
+	if (needs_recovery) {
+		ext4_msg(sb, KERN_INFO, "recovery complete");
+		err = ext4_mark_recovery_complete(sb, es);
+		if (err)
+			goto failed_mount8;
+	}
+	if (EXT4_SB(sb)->s_journal) {
+		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
+			descr = " journalled data mode";
+		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
+			descr = " ordered data mode";
+		else
+			descr = " writeback data mode";
+	} else
+		descr = "out journal";
+
+	if (test_opt(sb, DISCARD)) {
+		struct request_queue *q = bdev_get_queue(sb->s_bdev);
+		if (!blk_queue_discard(q))
+			ext4_msg(sb, KERN_WARNING,
+				 "mounting with \"discard\" option, but "
+				 "the device does not support discard");
+	}
+
+	if (___ratelimit(&ext4_mount_msg_ratelimit, "EXT4-fs mount"))
+		ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
+			 "Opts: %.*s%s%s", descr,
+			 (int) sizeof(sbi->s_es->s_mount_opts),
+			 sbi->s_es->s_mount_opts,
+			 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
+
+	if (es->s_error_count)
+		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
+
+	/* Enable message ratelimiting. Default is 10 messages per 5 secs. */
+	ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
+	ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
+	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
+	atomic_set(&sbi->s_warning_count, 0);
+	atomic_set(&sbi->s_msg_count, 0);
+
+	kfree(orig_data);
+	return 0;
+
+cantfind_ext4:
+	if (!silent)
+		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
+	goto failed_mount;
+
+failed_mount8:
+	ext4_unregister_sysfs(sb);
+	kobject_put(&sbi->s_kobj);
+failed_mount7:
+	ext4_unregister_li_request(sb);
+failed_mount6:
+	ext4_mb_release(sb);
+	rcu_read_lock();
+	flex_groups = rcu_dereference(sbi->s_flex_groups);
+	if (flex_groups) {
+		for (i = 0; i < sbi->s_flex_groups_allocated; i++)
+			kvfree(flex_groups[i]);
+		kvfree(flex_groups);
+	}
+	rcu_read_unlock();
+	percpu_counter_destroy(&sbi->s_freeclusters_counter);
+	percpu_counter_destroy(&sbi->s_freeinodes_counter);
+	percpu_counter_destroy(&sbi->s_dirs_counter);
+	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
+	percpu_counter_destroy(&sbi->s_sra_exceeded_retry_limit);
+	percpu_free_rwsem(&sbi->s_writepages_rwsem);
+failed_mount5:
+	ext4_ext_release(sb);
+	ext4_release_system_zone(sb);
+failed_mount4a:
+	dput(sb->s_root);
+	sb->s_root = NULL;
+failed_mount4:
+	ext4_msg(sb, KERN_ERR, "mount failed");
+	if (EXT4_SB(sb)->rsv_conversion_wq)
+		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
+failed_mount_wq:
+	ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+	sbi->s_ea_inode_cache = NULL;
+
+	ext4_xattr_destroy_cache(sbi->s_ea_block_cache);
+	sbi->s_ea_block_cache = NULL;
+
+	if (sbi->s_journal) {
+		jbd2_journal_destroy(sbi->s_journal);
+		sbi->s_journal = NULL;
+	}
+failed_mount3a:
+	ext4_es_unregister_shrinker(sbi);
+failed_mount3:
+	del_timer_sync(&sbi->s_err_report);
+	ext4_stop_mmpd(sbi);
+failed_mount2:
+	rcu_read_lock();
+	group_desc = rcu_dereference(sbi->s_group_desc);
+	for (i = 0; i < db_count; i++)
+		brelse(group_desc[i]);
+	kvfree(group_desc);
+	rcu_read_unlock();
+failed_mount:
+	if (sbi->s_chksum_driver)
+		crypto_free_shash(sbi->s_chksum_driver);
+
+#ifdef CONFIG_UNICODE
+	utf8_unload(sb->s_encoding);
+#endif
+
+#ifdef CONFIG_QUOTA
+	for (i = 0; i < EXT4_MAXQUOTAS; i++)
+		kfree(get_qf_name(sb, sbi, i));
+#endif
+	fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
+	/* ext4_blkdev_remove() calls kill_bdev(), release bh before it. */
+	brelse(bh);
+	ext4_blkdev_remove(sbi);
+out_fail:
+	invalidate_bdev(sb->s_bdev);
+	sb->s_fs_info = NULL;
+	kfree(sbi->s_blockgroup_lock);
+out_free_base:
+	kfree(sbi);
+	kfree(orig_data);
+	fs_put_dax(dax_dev);
+	return err ? err : ret;
+}
+
+/*
+ * Setup any per-fs journal parameters now.  We'll do this both on
+ * initial mount, once the journal has been initialised but before we've
+ * done any recovery; and again on any subsequent remount.
+ */
+static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	journal->j_commit_interval = sbi->s_commit_interval;
+	journal->j_min_batch_time = sbi->s_min_batch_time;
+	journal->j_max_batch_time = sbi->s_max_batch_time;
+	ext4_fc_init(sb, journal);
+
+	write_lock(&journal->j_state_lock);
+	if (test_opt(sb, BARRIER))
+		journal->j_flags |= JBD2_BARRIER;
+	else
+		journal->j_flags &= ~JBD2_BARRIER;
+	if (test_opt(sb, DATA_ERR_ABORT))
+		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
+	else
+		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
+	write_unlock(&journal->j_state_lock);
+}
+
+static struct inode *ext4_get_journal_inode(struct super_block *sb,
+					     unsigned int journal_inum)
+{
+	struct inode *journal_inode;
+
+	/*
+	 * Test for the existence of a valid inode on disk.  Bad things
+	 * happen if we iget() an unused inode, as the subsequent iput()
+	 * will try to delete it.
+	 */
+	journal_inode = ext4_iget(sb, journal_inum, EXT4_IGET_SPECIAL);
+	if (IS_ERR(journal_inode)) {
+		ext4_msg(sb, KERN_ERR, "no journal found");
+		return NULL;
+	}
+	if (!journal_inode->i_nlink) {
+		make_bad_inode(journal_inode);
+		iput(journal_inode);
+		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
+		return NULL;
+	}
+
+	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
+		  journal_inode, journal_inode->i_size);
+	if (!S_ISREG(journal_inode->i_mode) || IS_ENCRYPTED(journal_inode)) {
+		ext4_msg(sb, KERN_ERR, "invalid journal inode");
+		iput(journal_inode);
+		return NULL;
+	}
+	return journal_inode;
+}
+
+static journal_t *ext4_get_journal(struct super_block *sb,
+				   unsigned int journal_inum)
+{
+	struct inode *journal_inode;
+	journal_t *journal;
+
+	if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
+		return NULL;
+
+	journal_inode = ext4_get_journal_inode(sb, journal_inum);
+	if (!journal_inode)
+		return NULL;
+
+	journal = jbd2_journal_init_inode(journal_inode);
+	if (!journal) {
+		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
+		iput(journal_inode);
+		return NULL;
+	}
+	journal->j_private = sb;
+	ext4_init_journal_params(sb, journal);
+	return journal;
+}
+
+static journal_t *ext4_get_dev_journal(struct super_block *sb,
+				       dev_t j_dev)
+{
+	struct buffer_head *bh;
+	journal_t *journal;
+	ext4_fsblk_t start;
+	ext4_fsblk_t len;
+	int hblock, blocksize;
+	ext4_fsblk_t sb_block;
+	unsigned long offset;
+	struct ext4_super_block *es;
+	struct block_device *bdev;
+
+	if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
+		return NULL;
+
+	bdev = ext4_blkdev_get(j_dev, sb);
+	if (bdev == NULL)
+		return NULL;
+
+	blocksize = sb->s_blocksize;
+	hblock = bdev_logical_block_size(bdev);
+	if (blocksize < hblock) {
+		ext4_msg(sb, KERN_ERR,
+			"blocksize too small for journal device");
+		goto out_bdev;
+	}
+
+	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
+	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
+	set_blocksize(bdev, blocksize);
+	if (!(bh = __bread(bdev, sb_block, blocksize))) {
+		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
+		       "external journal");
+		goto out_bdev;
+	}
+
+	es = (struct ext4_super_block *) (bh->b_data + offset);
+	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
+	    !(le32_to_cpu(es->s_feature_incompat) &
+	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
+		ext4_msg(sb, KERN_ERR, "external journal has "
+					"bad superblock");
+		brelse(bh);
+		goto out_bdev;
+	}
+
+	if ((le32_to_cpu(es->s_feature_ro_compat) &
+	     EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+	    es->s_checksum != ext4_superblock_csum(sb, es)) {
+		ext4_msg(sb, KERN_ERR, "external journal has "
+				       "corrupt superblock");
+		brelse(bh);
+		goto out_bdev;
+	}
+
+	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
+		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
+		brelse(bh);
+		goto out_bdev;
+	}
+
+	len = ext4_blocks_count(es);
+	start = sb_block + 1;
+	brelse(bh);	/* we're done with the superblock */
+
+	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
+					start, len, blocksize);
+	if (!journal) {
+		ext4_msg(sb, KERN_ERR, "failed to create device journal");
+		goto out_bdev;
+	}
+	journal->j_private = sb;
+	if (ext4_read_bh_lock(journal->j_sb_buffer, REQ_META | REQ_PRIO, true)) {
+		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
+		goto out_journal;
+	}
+	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
+		ext4_msg(sb, KERN_ERR, "External journal has more than one "
+					"user (unsupported) - %d",
+			be32_to_cpu(journal->j_superblock->s_nr_users));
+		goto out_journal;
+	}
+	EXT4_SB(sb)->s_journal_bdev = bdev;
+	ext4_init_journal_params(sb, journal);
+	return journal;
+
+out_journal:
+	jbd2_journal_destroy(journal);
+out_bdev:
+	ext4_blkdev_put(bdev);
+	return NULL;
+}
+
+static int ext4_load_journal(struct super_block *sb,
+			     struct ext4_super_block *es,
+			     unsigned long journal_devnum)
+{
+	journal_t *journal;
+	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
+	dev_t journal_dev;
+	int err = 0;
+	int really_read_only;
+	int journal_dev_ro;
+
+	if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
+		return -EFSCORRUPTED;
+
+	if (journal_devnum &&
+	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
+		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
+			"numbers have changed");
+		journal_dev = new_decode_dev(journal_devnum);
+	} else
+		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
+
+	if (journal_inum && journal_dev) {
+		ext4_msg(sb, KERN_ERR,
+			 "filesystem has both journal inode and journal device!");
+		return -EINVAL;
+	}
+
+	if (journal_inum) {
+		journal = ext4_get_journal(sb, journal_inum);
+		if (!journal)
+			return -EINVAL;
+	} else {
+		journal = ext4_get_dev_journal(sb, journal_dev);
+		if (!journal)
+			return -EINVAL;
+	}
+
+	journal_dev_ro = bdev_read_only(journal->j_dev);
+	really_read_only = bdev_read_only(sb->s_bdev) | journal_dev_ro;
+
+	if (journal_dev_ro && !sb_rdonly(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			 "journal device read-only, try mounting with '-o ro'");
+		err = -EROFS;
+		goto err_out;
+	}
+
+	/*
+	 * Are we loading a blank journal or performing recovery after a
+	 * crash?  For recovery, we need to check in advance whether we
+	 * can get read-write access to the device.
+	 */
+	if (ext4_has_feature_journal_needs_recovery(sb)) {
+		if (sb_rdonly(sb)) {
+			ext4_msg(sb, KERN_INFO, "INFO: recovery "
+					"required on readonly filesystem");
+			if (really_read_only) {
+				ext4_msg(sb, KERN_ERR, "write access "
+					"unavailable, cannot proceed "
+					"(try mounting with noload)");
+				err = -EROFS;
+				goto err_out;
+			}
+			ext4_msg(sb, KERN_INFO, "write access will "
+			       "be enabled during recovery");
+		}
+	}
+
+	if (!(journal->j_flags & JBD2_BARRIER))
+		ext4_msg(sb, KERN_INFO, "barriers disabled");
+
+	if (!ext4_has_feature_journal_needs_recovery(sb))
+		err = jbd2_journal_wipe(journal, !really_read_only);
+	if (!err) {
+		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
+		if (save)
+			memcpy(save, ((char *) es) +
+			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
+		err = jbd2_journal_load(journal);
+		if (save)
+			memcpy(((char *) es) + EXT4_S_ERR_START,
+			       save, EXT4_S_ERR_LEN);
+		kfree(save);
+	}
+
+	if (err) {
+		ext4_msg(sb, KERN_ERR, "error loading journal");
+		goto err_out;
+	}
+
+	EXT4_SB(sb)->s_journal = journal;
+	err = ext4_clear_journal_err(sb, es);
+	if (err) {
+		EXT4_SB(sb)->s_journal = NULL;
+		jbd2_journal_destroy(journal);
+		return err;
+	}
+
+	if (!really_read_only && journal_devnum &&
+	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
+		es->s_journal_dev = cpu_to_le32(journal_devnum);
+
+		/* Make sure we flush the recovery flag to disk. */
+		ext4_commit_super(sb, 1);
+	}
+
+	return 0;
+
+err_out:
+	jbd2_journal_destroy(journal);
+	return err;
+}
+
+static int ext4_commit_super(struct super_block *sb, int sync)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
+	int error = 0;
+
+	if (!sbh)
+		return -EINVAL;
+	if (block_device_ejected(sb))
+		return -ENODEV;
+
+	/*
+	 * If the file system is mounted read-only, don't update the
+	 * superblock write time.  This avoids updating the superblock
+	 * write time when we are mounting the root file system
+	 * read/only but we need to replay the journal; at that point,
+	 * for people who are east of GMT and who make their clock
+	 * tick in localtime for Windows bug-for-bug compatibility,
+	 * the clock is set in the future, and this will cause e2fsck
+	 * to complain and force a full file system check.
+	 */
+	if (!(sb->s_flags & SB_RDONLY))
+		ext4_update_tstamp(es, s_wtime);
+	if (sb->s_bdev->bd_part)
+		es->s_kbytes_written =
+			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
+			    ((part_stat_read(sb->s_bdev->bd_part,
+					     sectors[STAT_WRITE]) -
+			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
+	else
+		es->s_kbytes_written =
+			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
+	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
+		ext4_free_blocks_count_set(es,
+			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
+				&EXT4_SB(sb)->s_freeclusters_counter)));
+	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeinodes_counter))
+		es->s_free_inodes_count =
+			cpu_to_le32(percpu_counter_sum_positive(
+				&EXT4_SB(sb)->s_freeinodes_counter));
+	BUFFER_TRACE(sbh, "marking dirty");
+	ext4_superblock_csum_set(sb);
+	if (sync)
+		lock_buffer(sbh);
+	if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {
+		/*
+		 * Oh, dear.  A previous attempt to write the
+		 * superblock failed.  This could happen because the
+		 * USB device was yanked out.  Or it could happen to
+		 * be a transient write error and maybe the block will
+		 * be remapped.  Nothing we can do but to retry the
+		 * write and hope for the best.
+		 */
+		ext4_msg(sb, KERN_ERR, "previous I/O error to "
+		       "superblock detected");
+		clear_buffer_write_io_error(sbh);
+		set_buffer_uptodate(sbh);
+	}
+	mark_buffer_dirty(sbh);
+	if (sync) {
+		unlock_buffer(sbh);
+		error = __sync_dirty_buffer(sbh,
+			REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0));
+		if (buffer_write_io_error(sbh)) {
+			ext4_msg(sb, KERN_ERR, "I/O error while writing "
+			       "superblock");
+			clear_buffer_write_io_error(sbh);
+			set_buffer_uptodate(sbh);
+		}
+	}
+	return error;
+}
+
+/*
+ * Have we just finished recovery?  If so, and if we are mounting (or
+ * remounting) the filesystem readonly, then we will end up with a
+ * consistent fs on disk.  Record that fact.
+ */
+static int ext4_mark_recovery_complete(struct super_block *sb,
+				       struct ext4_super_block *es)
+{
+	int err;
+	journal_t *journal = EXT4_SB(sb)->s_journal;
+
+	if (!ext4_has_feature_journal(sb)) {
+		if (journal != NULL) {
+			ext4_error(sb, "Journal got removed while the fs was "
+				   "mounted!");
+			return -EFSCORRUPTED;
+		}
+		return 0;
+	}
+	jbd2_journal_lock_updates(journal);
+	err = jbd2_journal_flush(journal);
+	if (err < 0)
+		goto out;
+
+	if (ext4_has_feature_journal_needs_recovery(sb) && sb_rdonly(sb)) {
+		ext4_clear_feature_journal_needs_recovery(sb);
+		ext4_commit_super(sb, 1);
+	}
+out:
+	jbd2_journal_unlock_updates(journal);
+	return err;
+}
+
+/*
+ * If we are mounting (or read-write remounting) a filesystem whose journal
+ * has recorded an error from a previous lifetime, move that error to the
+ * main filesystem now.
+ */
+static int ext4_clear_journal_err(struct super_block *sb,
+				   struct ext4_super_block *es)
+{
+	journal_t *journal;
+	int j_errno;
+	const char *errstr;
+
+	if (!ext4_has_feature_journal(sb)) {
+		ext4_error(sb, "Journal got removed while the fs was mounted!");
+		return -EFSCORRUPTED;
+	}
+
+	journal = EXT4_SB(sb)->s_journal;
+
+	/*
+	 * Now check for any error status which may have been recorded in the
+	 * journal by a prior ext4_error() or ext4_abort()
+	 */
+
+	j_errno = jbd2_journal_errno(journal);
+	if (j_errno) {
+		char nbuf[16];
+
+		errstr = ext4_decode_error(sb, j_errno, nbuf);
+		ext4_warning(sb, "Filesystem error recorded "
+			     "from previous mount: %s", errstr);
+		ext4_warning(sb, "Marking fs in need of filesystem check.");
+
+		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
+		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
+		ext4_commit_super(sb, 1);
+
+		jbd2_journal_clear_err(journal);
+		jbd2_journal_update_sb_errno(journal);
+	}
+	return 0;
+}
+
+/*
+ * Force the running and committing transactions to commit,
+ * and wait on the commit.
+ */
+int ext4_force_commit(struct super_block *sb)
+{
+	journal_t *journal;
+
+	if (sb_rdonly(sb))
+		return 0;
+
+	journal = EXT4_SB(sb)->s_journal;
+	return ext4_journal_force_commit(journal);
+}
+
+static int ext4_sync_fs(struct super_block *sb, int wait)
+{
+	int ret = 0;
+	tid_t target;
+	bool needs_barrier = false;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (unlikely(ext4_forced_shutdown(sbi)))
+		return 0;
+
+	trace_ext4_sync_fs(sb, wait);
+	flush_workqueue(sbi->rsv_conversion_wq);
+	/*
+	 * Writeback quota in non-journalled quota case - journalled quota has
+	 * no dirty dquots
+	 */
+	dquot_writeback_dquots(sb, -1);
+	/*
+	 * Data writeback is possible w/o journal transaction, so barrier must
+	 * being sent at the end of the function. But we can skip it if
+	 * transaction_commit will do it for us.
+	 */
+	if (sbi->s_journal) {
+		target = jbd2_get_latest_transaction(sbi->s_journal);
+		if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
+		    !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
+			needs_barrier = true;
+
+		if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
+			if (wait)
+				ret = jbd2_log_wait_commit(sbi->s_journal,
+							   target);
+		}
+	} else if (wait && test_opt(sb, BARRIER))
+		needs_barrier = true;
+	if (needs_barrier) {
+		int err;
+		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL);
+		if (!ret)
+			ret = err;
+	}
+
+	return ret;
+}
+
+/*
+ * LVM calls this function before a (read-only) snapshot is created.  This
+ * gives us a chance to flush the journal completely and mark the fs clean.
+ *
+ * Note that only this function cannot bring a filesystem to be in a clean
+ * state independently. It relies on upper layer to stop all data & metadata
+ * modifications.
+ */
+static int ext4_freeze(struct super_block *sb)
+{
+	int error = 0;
+	journal_t *journal;
+
+	if (sb_rdonly(sb))
+		return 0;
+
+	journal = EXT4_SB(sb)->s_journal;
+
+	if (journal) {
+		/* Now we set up the journal barrier. */
+		jbd2_journal_lock_updates(journal);
+
+		/*
+		 * Don't clear the needs_recovery flag if we failed to
+		 * flush the journal.
+		 */
+		error = jbd2_journal_flush(journal);
+		if (error < 0)
+			goto out;
+
+		/* Journal blocked and flushed, clear needs_recovery flag. */
+		ext4_clear_feature_journal_needs_recovery(sb);
+	}
+
+	error = ext4_commit_super(sb, 1);
+out:
+	if (journal)
+		/* we rely on upper layer to stop further updates */
+		jbd2_journal_unlock_updates(journal);
+	return error;
+}
+
+/*
+ * Called by LVM after the snapshot is done.  We need to reset the RECOVER
+ * flag here, even though the filesystem is not technically dirty yet.
+ */
+static int ext4_unfreeze(struct super_block *sb)
+{
+	if (sb_rdonly(sb) || ext4_forced_shutdown(EXT4_SB(sb)))
+		return 0;
+
+	if (EXT4_SB(sb)->s_journal) {
+		/* Reset the needs_recovery flag before the fs is unlocked. */
+		ext4_set_feature_journal_needs_recovery(sb);
+	}
+
+	ext4_commit_super(sb, 1);
+	return 0;
+}
+
+/*
+ * Structure to save mount options for ext4_remount's benefit
+ */
+struct ext4_mount_options {
+	unsigned long s_mount_opt;
+	unsigned long s_mount_opt2;
+	kuid_t s_resuid;
+	kgid_t s_resgid;
+	unsigned long s_commit_interval;
+	u32 s_min_batch_time, s_max_batch_time;
+#ifdef CONFIG_QUOTA
+	int s_jquota_fmt;
+	char *s_qf_names[EXT4_MAXQUOTAS];
+#endif
+};
+
+static int ext4_remount(struct super_block *sb, int *flags, char *data)
+{
+	struct ext4_super_block *es;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	unsigned long old_sb_flags, vfs_flags;
+	struct ext4_mount_options old_opts;
+	ext4_group_t g;
+	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
+	int err = 0;
+#ifdef CONFIG_QUOTA
+	int enable_quota = 0;
+	int i, j;
+	char *to_free[EXT4_MAXQUOTAS];
+#endif
+	char *orig_data = kstrdup(data, GFP_KERNEL);
+
+	if (data && !orig_data)
+		return -ENOMEM;
+
+	/* Store the original options */
+	old_sb_flags = sb->s_flags;
+	old_opts.s_mount_opt = sbi->s_mount_opt;
+	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
+	old_opts.s_resuid = sbi->s_resuid;
+	old_opts.s_resgid = sbi->s_resgid;
+	old_opts.s_commit_interval = sbi->s_commit_interval;
+	old_opts.s_min_batch_time = sbi->s_min_batch_time;
+	old_opts.s_max_batch_time = sbi->s_max_batch_time;
+#ifdef CONFIG_QUOTA
+	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
+	for (i = 0; i < EXT4_MAXQUOTAS; i++)
+		if (sbi->s_qf_names[i]) {
+			char *qf_name = get_qf_name(sb, sbi, i);
+
+			old_opts.s_qf_names[i] = kstrdup(qf_name, GFP_KERNEL);
+			if (!old_opts.s_qf_names[i]) {
+				for (j = 0; j < i; j++)
+					kfree(old_opts.s_qf_names[j]);
+				kfree(orig_data);
+				return -ENOMEM;
+			}
+		} else
+			old_opts.s_qf_names[i] = NULL;
+#endif
+	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
+		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
+
+	/*
+	 * Some options can be enabled by ext4 and/or by VFS mount flag
+	 * either way we need to make sure it matches in both *flags and
+	 * s_flags. Copy those selected flags from *flags to s_flags
+	 */
+	vfs_flags = SB_LAZYTIME | SB_I_VERSION;
+	sb->s_flags = (sb->s_flags & ~vfs_flags) | (*flags & vfs_flags);
+
+	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
+		err = -EINVAL;
+		goto restore_opts;
+	}
+
+	if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
+	    test_opt(sb, JOURNAL_CHECKSUM)) {
+		ext4_msg(sb, KERN_ERR, "changing journal_checksum "
+			 "during remount not supported; ignoring");
+		sbi->s_mount_opt ^= EXT4_MOUNT_JOURNAL_CHECKSUM;
+	}
+
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
+		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "both data=journal and delalloc");
+			err = -EINVAL;
+			goto restore_opts;
+		}
+		if (test_opt(sb, DIOREAD_NOLOCK)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "both data=journal and dioread_nolock");
+			err = -EINVAL;
+			goto restore_opts;
+		}
+	} else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA) {
+		if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				"journal_async_commit in data=ordered mode");
+			err = -EINVAL;
+			goto restore_opts;
+		}
+	}
+
+	if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_NO_MBCACHE) {
+		ext4_msg(sb, KERN_ERR, "can't enable nombcache during remount");
+		err = -EINVAL;
+		goto restore_opts;
+	}
+
+	if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
+		ext4_abort(sb, EXT4_ERR_ESHUTDOWN, "Abort forced by user");
+
+	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
+		(test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);
+
+	es = sbi->s_es;
+
+	if (sbi->s_journal) {
+		ext4_init_journal_params(sb, sbi->s_journal);
+		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
+	}
+
+	if ((bool)(*flags & SB_RDONLY) != sb_rdonly(sb)) {
+		if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED)) {
+			err = -EROFS;
+			goto restore_opts;
+		}
+
+		if (*flags & SB_RDONLY) {
+			err = sync_filesystem(sb);
+			if (err < 0)
+				goto restore_opts;
+			err = dquot_suspend(sb, -1);
+			if (err < 0)
+				goto restore_opts;
+
+			/*
+			 * First of all, the unconditional stuff we have to do
+			 * to disable replay of the journal when we next remount
+			 */
+			sb->s_flags |= SB_RDONLY;
+
+			/*
+			 * OK, test if we are remounting a valid rw partition
+			 * readonly, and if so set the rdonly flag and then
+			 * mark the partition as valid again.
+			 */
+			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
+			    (sbi->s_mount_state & EXT4_VALID_FS))
+				es->s_state = cpu_to_le16(sbi->s_mount_state);
+
+			if (sbi->s_journal) {
+				/*
+				 * We let remount-ro finish even if marking fs
+				 * as clean failed...
+				 */
+				ext4_mark_recovery_complete(sb, es);
+			}
+		} else {
+			/* Make sure we can mount this feature set readwrite */
+			if (ext4_has_feature_readonly(sb) ||
+			    !ext4_feature_set_ok(sb, 0)) {
+				err = -EROFS;
+				goto restore_opts;
+			}
+			/*
+			 * Make sure the group descriptor checksums
+			 * are sane.  If they aren't, refuse to remount r/w.
+			 */
+			for (g = 0; g < sbi->s_groups_count; g++) {
+				struct ext4_group_desc *gdp =
+					ext4_get_group_desc(sb, g, NULL);
+
+				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
+					ext4_msg(sb, KERN_ERR,
+	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
+		g, le16_to_cpu(ext4_group_desc_csum(sb, g, gdp)),
+					       le16_to_cpu(gdp->bg_checksum));
+					err = -EFSBADCRC;
+					goto restore_opts;
+				}
+			}
+
+			/*
+			 * If we have an unprocessed orphan list hanging
+			 * around from a previously readonly bdev mount,
+			 * require a full umount/remount for now.
+			 */
+			if (es->s_last_orphan) {
+				ext4_msg(sb, KERN_WARNING, "Couldn't "
+				       "remount RDWR because of unprocessed "
+				       "orphan inode list.  Please "
+				       "umount/remount instead");
+				err = -EINVAL;
+				goto restore_opts;
+			}
+
+			/*
+			 * Mounting a RDONLY partition read-write, so reread
+			 * and store the current valid flag.  (It may have
+			 * been changed by e2fsck since we originally mounted
+			 * the partition.)
+			 */
+			if (sbi->s_journal) {
+				err = ext4_clear_journal_err(sb, es);
+				if (err)
+					goto restore_opts;
+			}
+			sbi->s_mount_state = (le16_to_cpu(es->s_state) &
+					      ~EXT4_FC_REPLAY);
+
+			err = ext4_setup_super(sb, es, 0);
+			if (err)
+				goto restore_opts;
+
+			sb->s_flags &= ~SB_RDONLY;
+			if (ext4_has_feature_mmp(sb)) {
+				err = ext4_multi_mount_protect(sb,
+						le64_to_cpu(es->s_mmp_block));
+				if (err)
+					goto restore_opts;
+			}
+#ifdef CONFIG_QUOTA
+			enable_quota = 1;
+#endif
+		}
+	}
+
+	/*
+	 * Handle creation of system zone data early because it can fail.
+	 * Releasing of existing data is done when we are sure remount will
+	 * succeed.
+	 */
+	if (test_opt(sb, BLOCK_VALIDITY) && !sbi->s_system_blks) {
+		err = ext4_setup_system_zone(sb);
+		if (err)
+			goto restore_opts;
+	}
+
+	if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY)) {
+		err = ext4_commit_super(sb, 1);
+		if (err)
+			goto restore_opts;
+	}
+
+#ifdef CONFIG_QUOTA
+	if (enable_quota) {
+		if (sb_any_quota_suspended(sb))
+			dquot_resume(sb, -1);
+		else if (ext4_has_feature_quota(sb)) {
+			err = ext4_enable_quotas(sb);
+			if (err)
+				goto restore_opts;
+		}
+	}
+	/* Release old quota file names */
+	for (i = 0; i < EXT4_MAXQUOTAS; i++)
+		kfree(old_opts.s_qf_names[i]);
+#endif
+	if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks)
+		ext4_release_system_zone(sb);
+
+	/*
+	 * Reinitialize lazy itable initialization thread based on
+	 * current settings
+	 */
+	if (sb_rdonly(sb) || !test_opt(sb, INIT_INODE_TABLE))
+		ext4_unregister_li_request(sb);
+	else {
+		ext4_group_t first_not_zeroed;
+		first_not_zeroed = ext4_has_uninit_itable(sb);
+		ext4_register_li_request(sb, first_not_zeroed);
+	}
+
+	if (!ext4_has_feature_mmp(sb) || sb_rdonly(sb))
+		ext4_stop_mmpd(sbi);
+
+	/*
+	 * Some options can be enabled by ext4 and/or by VFS mount flag
+	 * either way we need to make sure it matches in both *flags and
+	 * s_flags. Copy those selected flags from s_flags to *flags
+	 */
+	*flags = (*flags & ~vfs_flags) | (sb->s_flags & vfs_flags);
+
+	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
+	kfree(orig_data);
+	return 0;
+
+restore_opts:
+	/*
+	 * If there was a failing r/w to ro transition, we may need to
+	 * re-enable quota
+	 */
+	if ((sb->s_flags & SB_RDONLY) && !(old_sb_flags & SB_RDONLY) &&
+	    sb_any_quota_suspended(sb))
+		dquot_resume(sb, -1);
+	sb->s_flags = old_sb_flags;
+	sbi->s_mount_opt = old_opts.s_mount_opt;
+	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
+	sbi->s_resuid = old_opts.s_resuid;
+	sbi->s_resgid = old_opts.s_resgid;
+	sbi->s_commit_interval = old_opts.s_commit_interval;
+	sbi->s_min_batch_time = old_opts.s_min_batch_time;
+	sbi->s_max_batch_time = old_opts.s_max_batch_time;
+	if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks)
+		ext4_release_system_zone(sb);
+#ifdef CONFIG_QUOTA
+	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
+	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
+		to_free[i] = get_qf_name(sb, sbi, i);
+		rcu_assign_pointer(sbi->s_qf_names[i], old_opts.s_qf_names[i]);
+	}
+	synchronize_rcu();
+	for (i = 0; i < EXT4_MAXQUOTAS; i++)
+		kfree(to_free[i]);
+#endif
+	if (!ext4_has_feature_mmp(sb) || sb_rdonly(sb))
+		ext4_stop_mmpd(sbi);
+	kfree(orig_data);
+	return err;
+}
+
+#ifdef CONFIG_QUOTA
+static int ext4_statfs_project(struct super_block *sb,
+			       kprojid_t projid, struct kstatfs *buf)
+{
+	struct kqid qid;
+	struct dquot *dquot;
+	u64 limit;
+	u64 curblock;
+
+	qid = make_kqid_projid(projid);
+	dquot = dqget(sb, qid);
+	if (IS_ERR(dquot))
+		return PTR_ERR(dquot);
+	spin_lock(&dquot->dq_dqb_lock);
+
+	limit = min_not_zero(dquot->dq_dqb.dqb_bsoftlimit,
+			     dquot->dq_dqb.dqb_bhardlimit);
+	limit >>= sb->s_blocksize_bits;
+
+	if (limit && buf->f_blocks > limit) {
+		curblock = (dquot->dq_dqb.dqb_curspace +
+			    dquot->dq_dqb.dqb_rsvspace) >> sb->s_blocksize_bits;
+		buf->f_blocks = limit;
+		buf->f_bfree = buf->f_bavail =
+			(buf->f_blocks > curblock) ?
+			 (buf->f_blocks - curblock) : 0;
+	}
+
+	limit = min_not_zero(dquot->dq_dqb.dqb_isoftlimit,
+			     dquot->dq_dqb.dqb_ihardlimit);
+	if (limit && buf->f_files > limit) {
+		buf->f_files = limit;
+		buf->f_ffree =
+			(buf->f_files > dquot->dq_dqb.dqb_curinodes) ?
+			 (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
+	}
+
+	spin_unlock(&dquot->dq_dqb_lock);
+	dqput(dquot);
+	return 0;
+}
+#endif
+
+static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	ext4_fsblk_t overhead = 0, resv_blocks;
+	u64 fsid;
+	s64 bfree;
+	resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
+
+	if (!test_opt(sb, MINIX_DF))
+		overhead = sbi->s_overhead;
+
+	buf->f_type = EXT4_SUPER_MAGIC;
+	buf->f_bsize = sb->s_blocksize;
+	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
+	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
+		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
+	/* prevent underflow in case that few free space is available */
+	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
+	buf->f_bavail = buf->f_bfree -
+			(ext4_r_blocks_count(es) + resv_blocks);
+	if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
+		buf->f_bavail = 0;
+	buf->f_files = le32_to_cpu(es->s_inodes_count);
+	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
+	buf->f_namelen = EXT4_NAME_LEN;
+	fsid = le64_to_cpup((void *)es->s_uuid) ^
+	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
+	buf->f_fsid = u64_to_fsid(fsid);
+
+#ifdef CONFIG_QUOTA
+	if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) &&
+	    sb_has_quota_limits_enabled(sb, PRJQUOTA))
+		ext4_statfs_project(sb, EXT4_I(dentry->d_inode)->i_projid, buf);
+#endif
+	return 0;
+}
+
+
+#ifdef CONFIG_QUOTA
+
+/*
+ * Helper functions so that transaction is started before we acquire dqio_sem
+ * to keep correct lock ordering of transaction > dqio_sem
+ */
+static inline struct inode *dquot_to_inode(struct dquot *dquot)
+{
+	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
+}
+
+static int ext4_write_dquot(struct dquot *dquot)
+{
+	int ret, err;
+	handle_t *handle;
+	struct inode *inode;
+
+	inode = dquot_to_inode(dquot);
+	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
+				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_commit(dquot);
+	err = ext4_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext4_acquire_dquot(struct dquot *dquot)
+{
+	int ret, err;
+	handle_t *handle;
+
+	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
+				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_acquire(dquot);
+	err = ext4_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext4_release_dquot(struct dquot *dquot)
+{
+	int ret, err;
+	handle_t *handle;
+
+	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
+				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
+	if (IS_ERR(handle)) {
+		/* Release dquot anyway to avoid endless cycle in dqput() */
+		dquot_release(dquot);
+		return PTR_ERR(handle);
+	}
+	ret = dquot_release(dquot);
+	err = ext4_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext4_mark_dquot_dirty(struct dquot *dquot)
+{
+	struct super_block *sb = dquot->dq_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	/* Are we journaling quotas? */
+	if (ext4_has_feature_quota(sb) ||
+	    sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
+		dquot_mark_dquot_dirty(dquot);
+		return ext4_write_dquot(dquot);
+	} else {
+		return dquot_mark_dquot_dirty(dquot);
+	}
+}
+
+static int ext4_write_info(struct super_block *sb, int type)
+{
+	int ret, err;
+	handle_t *handle;
+
+	/* Data block + inode block */
+	handle = ext4_journal_start_sb(sb, EXT4_HT_QUOTA, 2);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_commit_info(sb, type);
+	err = ext4_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+/*
+ * Turn on quotas during mount time - we need to find
+ * the quota file and such...
+ */
+static int ext4_quota_on_mount(struct super_block *sb, int type)
+{
+	return dquot_quota_on_mount(sb, get_qf_name(sb, EXT4_SB(sb), type),
+					EXT4_SB(sb)->s_jquota_fmt, type);
+}
+
+static void lockdep_set_quota_inode(struct inode *inode, int subclass)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	/* The first argument of lockdep_set_subclass has to be
+	 * *exactly* the same as the argument to init_rwsem() --- in
+	 * this case, in init_once() --- or lockdep gets unhappy
+	 * because the name of the lock is set using the
+	 * stringification of the argument to init_rwsem().
+	 */
+	(void) ei;	/* shut up clang warning if !CONFIG_LOCKDEP */
+	lockdep_set_subclass(&ei->i_data_sem, subclass);
+}
+
+/*
+ * Standard function to be called on quota_on
+ */
+static int ext4_quota_on(struct super_block *sb, int type, int format_id,
+			 const struct path *path)
+{
+	int err;
+
+	if (!test_opt(sb, QUOTA))
+		return -EINVAL;
+
+	/* Quotafile not on the same filesystem? */
+	if (path->dentry->d_sb != sb)
+		return -EXDEV;
+
+	/* Quota already enabled for this file? */
+	if (IS_NOQUOTA(d_inode(path->dentry)))
+		return -EBUSY;
+
+	/* Journaling quota? */
+	if (EXT4_SB(sb)->s_qf_names[type]) {
+		/* Quotafile not in fs root? */
+		if (path->dentry->d_parent != sb->s_root)
+			ext4_msg(sb, KERN_WARNING,
+				"Quota file not on filesystem root. "
+				"Journaled quota will not work");
+		sb_dqopt(sb)->flags |= DQUOT_NOLIST_DIRTY;
+	} else {
+		/*
+		 * Clear the flag just in case mount options changed since
+		 * last time.
+		 */
+		sb_dqopt(sb)->flags &= ~DQUOT_NOLIST_DIRTY;
+	}
+
+	/*
+	 * When we journal data on quota file, we have to flush journal to see
+	 * all updates to the file when we bypass pagecache...
+	 */
+	if (EXT4_SB(sb)->s_journal &&
+	    ext4_should_journal_data(d_inode(path->dentry))) {
+		/*
+		 * We don't need to lock updates but journal_flush() could
+		 * otherwise be livelocked...
+		 */
+		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+		if (err)
+			return err;
+	}
+
+	lockdep_set_quota_inode(path->dentry->d_inode, I_DATA_SEM_QUOTA);
+	err = dquot_quota_on(sb, type, format_id, path);
+	if (!err) {
+		struct inode *inode = d_inode(path->dentry);
+		handle_t *handle;
+
+		/*
+		 * Set inode flags to prevent userspace from messing with quota
+		 * files. If this fails, we return success anyway since quotas
+		 * are already enabled and this is not a hard failure.
+		 */
+		inode_lock(inode);
+		handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
+		if (IS_ERR(handle))
+			goto unlock_inode;
+		EXT4_I(inode)->i_flags |= EXT4_NOATIME_FL | EXT4_IMMUTABLE_FL;
+		inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
+				S_NOATIME | S_IMMUTABLE);
+		err = ext4_mark_inode_dirty(handle, inode);
+		ext4_journal_stop(handle);
+	unlock_inode:
+		inode_unlock(inode);
+		if (err)
+			dquot_quota_off(sb, type);
+	}
+	if (err)
+		lockdep_set_quota_inode(path->dentry->d_inode,
+					     I_DATA_SEM_NORMAL);
+	return err;
+}
+
+static inline bool ext4_check_quota_inum(int type, unsigned long qf_inum)
+{
+	switch (type) {
+	case USRQUOTA:
+		return qf_inum == EXT4_USR_QUOTA_INO;
+	case GRPQUOTA:
+		return qf_inum == EXT4_GRP_QUOTA_INO;
+	case PRJQUOTA:
+		return qf_inum >= EXT4_GOOD_OLD_FIRST_INO;
+	default:
+		BUG();
+	}
+}
+
+static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
+			     unsigned int flags)
+{
+	int err;
+	struct inode *qf_inode;
+	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
+	};
+
+	BUG_ON(!ext4_has_feature_quota(sb));
+
+	if (!qf_inums[type])
+		return -EPERM;
+
+	if (!ext4_check_quota_inum(type, qf_inums[type])) {
+		ext4_error(sb, "Bad quota inum: %lu, type: %d",
+				qf_inums[type], type);
+		return -EUCLEAN;
+	}
+
+	qf_inode = ext4_iget(sb, qf_inums[type], EXT4_IGET_SPECIAL);
+	if (IS_ERR(qf_inode)) {
+		ext4_error(sb, "Bad quota inode: %lu, type: %d",
+				qf_inums[type], type);
+		return PTR_ERR(qf_inode);
+	}
+
+	/* Don't account quota for quota files to avoid recursion */
+	qf_inode->i_flags |= S_NOQUOTA;
+	lockdep_set_quota_inode(qf_inode, I_DATA_SEM_QUOTA);
+	err = dquot_load_quota_inode(qf_inode, type, format_id, flags);
+	if (err)
+		lockdep_set_quota_inode(qf_inode, I_DATA_SEM_NORMAL);
+	iput(qf_inode);
+
+	return err;
+}
+
+/* Enable usage tracking for all quota types. */
+static int ext4_enable_quotas(struct super_block *sb)
+{
+	int type, err = 0;
+	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
+		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
+	};
+	bool quota_mopt[EXT4_MAXQUOTAS] = {
+		test_opt(sb, USRQUOTA),
+		test_opt(sb, GRPQUOTA),
+		test_opt(sb, PRJQUOTA),
+	};
+
+	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE | DQUOT_NOLIST_DIRTY;
+	for (type = 0; type < EXT4_MAXQUOTAS; type++) {
+		if (qf_inums[type]) {
+			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
+				DQUOT_USAGE_ENABLED |
+				(quota_mopt[type] ? DQUOT_LIMITS_ENABLED : 0));
+			if (err) {
+				ext4_warning(sb,
+					"Failed to enable quota tracking "
+					"(type=%d, err=%d, ino=%lu). "
+					"Please run e2fsck to fix.", type,
+					err, qf_inums[type]);
+				for (type--; type >= 0; type--) {
+					struct inode *inode;
+
+					inode = sb_dqopt(sb)->files[type];
+					if (inode)
+						inode = igrab(inode);
+					dquot_quota_off(sb, type);
+					if (inode) {
+						lockdep_set_quota_inode(inode,
+							I_DATA_SEM_NORMAL);
+						iput(inode);
+					}
+				}
+
+				return err;
+			}
+		}
+	}
+	return 0;
+}
+
+static int ext4_quota_off(struct super_block *sb, int type)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	handle_t *handle;
+	int err;
+
+	/* Force all delayed allocation blocks to be allocated.
+	 * Caller already holds s_umount sem */
+	if (test_opt(sb, DELALLOC))
+		sync_filesystem(sb);
+
+	if (!inode || !igrab(inode))
+		goto out;
+
+	err = dquot_quota_off(sb, type);
+	if (err || ext4_has_feature_quota(sb))
+		goto out_put;
+
+	inode_lock(inode);
+	/*
+	 * Update modification times of quota files when userspace can
+	 * start looking at them. If we fail, we return success anyway since
+	 * this is not a hard failure and quotas are already disabled.
+	 */
+	handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		goto out_unlock;
+	}
+	EXT4_I(inode)->i_flags &= ~(EXT4_NOATIME_FL | EXT4_IMMUTABLE_FL);
+	inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
+	inode->i_mtime = inode->i_ctime = current_time(inode);
+	err = ext4_mark_inode_dirty(handle, inode);
+	ext4_journal_stop(handle);
+out_unlock:
+	inode_unlock(inode);
+out_put:
+	lockdep_set_quota_inode(inode, I_DATA_SEM_NORMAL);
+	iput(inode);
+	return err;
+out:
+	return dquot_quota_off(sb, type);
+}
+
+/* Read data from quotafile - avoid pagecache and such because we cannot afford
+ * acquiring the locks... As quota files are never truncated and quota code
+ * itself serializes the operations (and no one else should touch the files)
+ * we don't have to be afraid of races */
+static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
+			       size_t len, loff_t off)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
+	int offset = off & (sb->s_blocksize - 1);
+	int tocopy;
+	size_t toread;
+	struct buffer_head *bh;
+	loff_t i_size = i_size_read(inode);
+
+	if (off > i_size)
+		return 0;
+	if (off+len > i_size)
+		len = i_size-off;
+	toread = len;
+	while (toread > 0) {
+		tocopy = sb->s_blocksize - offset < toread ?
+				sb->s_blocksize - offset : toread;
+		bh = ext4_bread(NULL, inode, blk, 0);
+		if (IS_ERR(bh))
+			return PTR_ERR(bh);
+		if (!bh)	/* A hole? */
+			memset(data, 0, tocopy);
+		else
+			memcpy(data, bh->b_data+offset, tocopy);
+		brelse(bh);
+		offset = 0;
+		toread -= tocopy;
+		data += tocopy;
+		blk++;
+	}
+	return len;
+}
+
+/* Write to quotafile (we know the transaction is already started and has
+ * enough credits) */
+static ssize_t ext4_quota_write(struct super_block *sb, int type,
+				const char *data, size_t len, loff_t off)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
+	int err = 0, err2 = 0, offset = off & (sb->s_blocksize - 1);
+	int retries = 0;
+	struct buffer_head *bh;
+	handle_t *handle = journal_current_handle();
+
+	if (!handle) {
+		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
+			" cancelled because transaction is not started",
+			(unsigned long long)off, (unsigned long long)len);
+		return -EIO;
+	}
+	/*
+	 * Since we account only one data block in transaction credits,
+	 * then it is impossible to cross a block boundary.
+	 */
+	if (sb->s_blocksize - offset < len) {
+		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
+			" cancelled because not block aligned",
+			(unsigned long long)off, (unsigned long long)len);
+		return -EIO;
+	}
+
+	do {
+		bh = ext4_bread(handle, inode, blk,
+				EXT4_GET_BLOCKS_CREATE |
+				EXT4_GET_BLOCKS_METADATA_NOFAIL);
+	} while (PTR_ERR(bh) == -ENOSPC &&
+		 ext4_should_retry_alloc(inode->i_sb, &retries));
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+	if (!bh)
+		goto out;
+	BUFFER_TRACE(bh, "get write access");
+	err = ext4_journal_get_write_access(handle, bh);
+	if (err) {
+		brelse(bh);
+		return err;
+	}
+	lock_buffer(bh);
+	memcpy(bh->b_data+offset, data, len);
+	flush_dcache_page(bh->b_page);
+	unlock_buffer(bh);
+	err = ext4_handle_dirty_metadata(handle, NULL, bh);
+	brelse(bh);
+out:
+	if (inode->i_size < off + len) {
+		i_size_write(inode, off + len);
+		EXT4_I(inode)->i_disksize = inode->i_size;
+		err2 = ext4_mark_inode_dirty(handle, inode);
+		if (unlikely(err2 && !err))
+			err = err2;
+	}
+	return err ? err : len;
+}
+#endif
+
+static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
+		       const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
+}
+
+#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
+static inline void register_as_ext2(void)
+{
+	int err = register_filesystem(&ext2_fs_type);
+	if (err)
+		printk(KERN_WARNING
+		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
+}
+
+static inline void unregister_as_ext2(void)
+{
+	unregister_filesystem(&ext2_fs_type);
+}
+
+static inline int ext2_feature_set_ok(struct super_block *sb)
+{
+	if (ext4_has_unknown_ext2_incompat_features(sb))
+		return 0;
+	if (sb_rdonly(sb))
+		return 1;
+	if (ext4_has_unknown_ext2_ro_compat_features(sb))
+		return 0;
+	return 1;
+}
+#else
+static inline void register_as_ext2(void) { }
+static inline void unregister_as_ext2(void) { }
+static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
+#endif
+
+static inline void register_as_ext3(void)
+{
+	int err = register_filesystem(&ext3_fs_type);
+	if (err)
+		printk(KERN_WARNING
+		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
+}
+
+static inline void unregister_as_ext3(void)
+{
+	unregister_filesystem(&ext3_fs_type);
+}
+
+static inline int ext3_feature_set_ok(struct super_block *sb)
+{
+	if (ext4_has_unknown_ext3_incompat_features(sb))
+		return 0;
+	if (!ext4_has_feature_journal(sb))
+		return 0;
+	if (sb_rdonly(sb))
+		return 1;
+	if (ext4_has_unknown_ext3_ro_compat_features(sb))
+		return 0;
+	return 1;
+}
+
+static struct file_system_type ext4_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ext4",
+	.mount		= ext4_mount,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("ext4");
+
+/* Shared across all ext4 file systems */
+wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
+
+static int __init ext4_init_fs(void)
+{
+	int i, err;
+
+	ratelimit_state_init(&ext4_mount_msg_ratelimit, 30 * HZ, 64);
+	ext4_li_info = NULL;
+	mutex_init(&ext4_li_mtx);
+
+	/* Build-time check for flags consistency */
+	ext4_check_flag_values();
+
+	for (i = 0; i < EXT4_WQ_HASH_SZ; i++)
+		init_waitqueue_head(&ext4__ioend_wq[i]);
+
+	err = ext4_init_es();
+	if (err)
+		return err;
+
+	err = ext4_init_pending();
+	if (err)
+		goto out7;
+
+	err = ext4_init_post_read_processing();
+	if (err)
+		goto out6;
+
+	err = ext4_init_pageio();
+	if (err)
+		goto out5;
+
+	err = ext4_init_system_zone();
+	if (err)
+		goto out4;
+
+	err = ext4_init_sysfs();
+	if (err)
+		goto out3;
+
+	err = ext4_init_mballoc();
+	if (err)
+		goto out2;
+	err = init_inodecache();
+	if (err)
+		goto out1;
+
+	err = ext4_fc_init_dentry_cache();
+	if (err)
+		goto out05;
+
+	register_as_ext3();
+	register_as_ext2();
+	err = register_filesystem(&ext4_fs_type);
+	if (err)
+		goto out;
+
+	return 0;
+out:
+	unregister_as_ext2();
+	unregister_as_ext3();
+	ext4_fc_destroy_dentry_cache();
+out05:
+	destroy_inodecache();
+out1:
+	ext4_exit_mballoc();
+out2:
+	ext4_exit_sysfs();
+out3:
+	ext4_exit_system_zone();
+out4:
+	ext4_exit_pageio();
+out5:
+	ext4_exit_post_read_processing();
+out6:
+	ext4_exit_pending();
+out7:
+	ext4_exit_es();
+
+	return err;
+}
+
+static void __exit ext4_exit_fs(void)
+{
+	ext4_destroy_lazyinit_thread();
+	unregister_as_ext2();
+	unregister_as_ext3();
+	unregister_filesystem(&ext4_fs_type);
+	ext4_fc_destroy_dentry_cache();
+	destroy_inodecache();
+	ext4_exit_mballoc();
+	ext4_exit_sysfs();
+	ext4_exit_system_zone();
+	ext4_exit_pageio();
+	ext4_exit_post_read_processing();
+	ext4_exit_es();
+	ext4_exit_pending();
+}
+
+MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
+MODULE_DESCRIPTION("Fourth Extended Filesystem");
+MODULE_LICENSE("GPL");
+MODULE_SOFTDEP("pre: crc32c");
+module_init(ext4_init_fs)
+module_exit(ext4_exit_fs)
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
new file mode 100644
index 000000000..a9457fed3
--- /dev/null
+++ b/fs/ext4/symlink.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/symlink.c
+ *
+ * Only fast symlinks left here - the rest is done by generic code. AV, 1999
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/symlink.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 symlink handling code
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include "ext4.h"
+#include "xattr.h"
+
+static const char *ext4_encrypted_get_link(struct dentry *dentry,
+					   struct inode *inode,
+					   struct delayed_call *done)
+{
+	struct page *cpage = NULL;
+	const void *caddr;
+	unsigned int max_size;
+	const char *paddr;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	if (ext4_inode_is_fast_symlink(inode)) {
+		caddr = EXT4_I(inode)->i_data;
+		max_size = sizeof(EXT4_I(inode)->i_data);
+	} else {
+		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
+		if (IS_ERR(cpage))
+			return ERR_CAST(cpage);
+		caddr = page_address(cpage);
+		max_size = inode->i_sb->s_blocksize;
+	}
+
+	paddr = fscrypt_get_symlink(inode, caddr, max_size, done);
+	if (cpage)
+		put_page(cpage);
+	return paddr;
+}
+
+static int ext4_encrypted_symlink_getattr(const struct path *path,
+					  struct kstat *stat, u32 request_mask,
+					  unsigned int query_flags)
+{
+	ext4_getattr(path, stat, request_mask, query_flags);
+
+	return fscrypt_symlink_getattr(path, stat);
+}
+
+const struct inode_operations ext4_encrypted_symlink_inode_operations = {
+	.get_link	= ext4_encrypted_get_link,
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_encrypted_symlink_getattr,
+	.listxattr	= ext4_listxattr,
+};
+
+const struct inode_operations ext4_symlink_inode_operations = {
+	.get_link	= page_get_link,
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_getattr,
+	.listxattr	= ext4_listxattr,
+};
+
+const struct inode_operations ext4_fast_symlink_inode_operations = {
+	.get_link	= simple_get_link,
+	.setattr	= ext4_setattr,
+	.getattr	= ext4_getattr,
+	.listxattr	= ext4_listxattr,
+};
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
new file mode 100644
index 000000000..b0bb4a92c
--- /dev/null
+++ b/fs/ext4/sysfs.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/sysfs.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Theodore Ts'o (tytso@mit.edu)
+ *
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/proc_fs.h>
+#include <linux/part_stat.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+
+typedef enum {
+	attr_noop,
+	attr_delayed_allocation_blocks,
+	attr_session_write_kbytes,
+	attr_lifetime_write_kbytes,
+	attr_reserved_clusters,
+	attr_sra_exceeded_retry_limit,
+	attr_inode_readahead,
+	attr_trigger_test_error,
+	attr_first_error_time,
+	attr_last_error_time,
+	attr_feature,
+	attr_pointer_ui,
+	attr_pointer_ul,
+	attr_pointer_u64,
+	attr_pointer_u8,
+	attr_pointer_string,
+	attr_pointer_atomic,
+	attr_journal_task,
+} attr_id_t;
+
+typedef enum {
+	ptr_explicit,
+	ptr_ext4_sb_info_offset,
+	ptr_ext4_super_block_offset,
+} attr_ptr_t;
+
+static const char proc_dirname[] = "fs/ext4";
+static struct proc_dir_entry *ext4_proc_root;
+
+struct ext4_attr {
+	struct attribute attr;
+	short attr_id;
+	short attr_ptr;
+	unsigned short attr_size;
+	union {
+		int offset;
+		void *explicit_ptr;
+	} u;
+};
+
+static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
+{
+	struct super_block *sb = sbi->s_buddy_cache->i_sb;
+
+	if (!sb->s_bdev->bd_part)
+		return snprintf(buf, PAGE_SIZE, "0\n");
+	return snprintf(buf, PAGE_SIZE, "%lu\n",
+			(part_stat_read(sb->s_bdev->bd_part,
+					sectors[STAT_WRITE]) -
+			 sbi->s_sectors_written_start) >> 1);
+}
+
+static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
+{
+	struct super_block *sb = sbi->s_buddy_cache->i_sb;
+
+	if (!sb->s_bdev->bd_part)
+		return snprintf(buf, PAGE_SIZE, "0\n");
+	return snprintf(buf, PAGE_SIZE, "%llu\n",
+			(unsigned long long)(sbi->s_kbytes_written +
+			((part_stat_read(sb->s_bdev->bd_part,
+					 sectors[STAT_WRITE]) -
+			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
+}
+
+static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
+					  const char *buf, size_t count)
+{
+	unsigned long t;
+	int ret;
+
+	ret = kstrtoul(skip_spaces(buf), 0, &t);
+	if (ret)
+		return ret;
+
+	if (t && (!is_power_of_2(t) || t > 0x40000000))
+		return -EINVAL;
+
+	sbi->s_inode_readahead_blks = t;
+	return count;
+}
+
+static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
+				   const char *buf, size_t count)
+{
+	unsigned long long val;
+	ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
+				 sbi->s_cluster_bits);
+	int ret;
+
+	ret = kstrtoull(skip_spaces(buf), 0, &val);
+	if (ret || val >= clusters)
+		return -EINVAL;
+
+	atomic64_set(&sbi->s_resv_clusters, val);
+	return count;
+}
+
+static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
+				  const char *buf, size_t count)
+{
+	int len = count;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (len && buf[len-1] == '\n')
+		len--;
+
+	if (len)
+		ext4_error(sbi->s_sb, "%.*s", len, buf);
+	return count;
+}
+
+static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
+{
+	if (!sbi->s_journal)
+		return snprintf(buf, PAGE_SIZE, "<none>\n");
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+			task_pid_vnr(sbi->s_journal->j_task));
+}
+
+#define EXT4_ATTR(_name,_mode,_id)					\
+static struct ext4_attr ext4_attr_##_name = {				\
+	.attr = {.name = __stringify(_name), .mode = _mode },		\
+	.attr_id = attr_##_id,						\
+}
+
+#define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
+
+#define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
+
+#define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)	\
+static struct ext4_attr ext4_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.attr_id = attr_##_id,					\
+	.attr_ptr = ptr_##_struct##_offset,			\
+	.u = {							\
+		.offset = offsetof(struct _struct, _elname),\
+	},							\
+}
+
+#define EXT4_ATTR_STRING(_name,_mode,_size,_struct,_elname)	\
+static struct ext4_attr ext4_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.attr_id = attr_pointer_string,				\
+	.attr_size = _size,					\
+	.attr_ptr = ptr_##_struct##_offset,			\
+	.u = {							\
+		.offset = offsetof(struct _struct, _elname),\
+	},							\
+}
+
+#define EXT4_RO_ATTR_ES_UI(_name,_elname)				\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
+
+#define EXT4_RO_ATTR_ES_U8(_name,_elname)				\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_u8, ext4_super_block, _elname)
+
+#define EXT4_RO_ATTR_ES_U64(_name,_elname)				\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_u64, ext4_super_block, _elname)
+
+#define EXT4_RO_ATTR_ES_STRING(_name,_elname,_size)			\
+	EXT4_ATTR_STRING(_name, 0444, _size, ext4_super_block, _elname)
+
+#define EXT4_RW_ATTR_SBI_UI(_name,_elname)	\
+	EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
+
+#define EXT4_RW_ATTR_SBI_UL(_name,_elname)	\
+	EXT4_ATTR_OFFSET(_name, 0644, pointer_ul, ext4_sb_info, _elname)
+
+#define EXT4_RO_ATTR_SBI_ATOMIC(_name,_elname)	\
+	EXT4_ATTR_OFFSET(_name, 0444, pointer_atomic, ext4_sb_info, _elname)
+
+#define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
+static struct ext4_attr ext4_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.attr_id = attr_##_id,					\
+	.attr_ptr = ptr_explicit,				\
+	.u = {							\
+		.explicit_ptr = _ptr,				\
+	},							\
+}
+
+#define ATTR_LIST(name) &ext4_attr_##name.attr
+
+EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
+EXT4_ATTR_FUNC(session_write_kbytes, 0444);
+EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
+EXT4_ATTR_FUNC(reserved_clusters, 0644);
+EXT4_ATTR_FUNC(sra_exceeded_retry_limit, 0444);
+
+EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
+		 ext4_sb_info, s_inode_readahead_blks);
+EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
+EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
+EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
+EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
+EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
+EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
+EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
+EXT4_RW_ATTR_SBI_UI(mb_max_inode_prealloc, s_mb_max_inode_prealloc);
+EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
+EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
+EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
+#ifdef CONFIG_EXT4_DEBUG
+EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail);
+#endif
+EXT4_RO_ATTR_SBI_ATOMIC(warning_count, s_warning_count);
+EXT4_RO_ATTR_SBI_ATOMIC(msg_count, s_msg_count);
+EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
+EXT4_RO_ATTR_ES_U8(first_error_errcode, s_first_error_errcode);
+EXT4_RO_ATTR_ES_U8(last_error_errcode, s_last_error_errcode);
+EXT4_RO_ATTR_ES_UI(first_error_ino, s_first_error_ino);
+EXT4_RO_ATTR_ES_UI(last_error_ino, s_last_error_ino);
+EXT4_RO_ATTR_ES_U64(first_error_block, s_first_error_block);
+EXT4_RO_ATTR_ES_U64(last_error_block, s_last_error_block);
+EXT4_RO_ATTR_ES_UI(first_error_line, s_first_error_line);
+EXT4_RO_ATTR_ES_UI(last_error_line, s_last_error_line);
+EXT4_RO_ATTR_ES_STRING(first_error_func, s_first_error_func, 32);
+EXT4_RO_ATTR_ES_STRING(last_error_func, s_last_error_func, 32);
+EXT4_ATTR(first_error_time, 0444, first_error_time);
+EXT4_ATTR(last_error_time, 0444, last_error_time);
+EXT4_ATTR(journal_task, 0444, journal_task);
+EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch);
+EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit);
+
+static unsigned int old_bump_val = 128;
+EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
+
+static struct attribute *ext4_attrs[] = {
+	ATTR_LIST(delayed_allocation_blocks),
+	ATTR_LIST(session_write_kbytes),
+	ATTR_LIST(lifetime_write_kbytes),
+	ATTR_LIST(reserved_clusters),
+	ATTR_LIST(sra_exceeded_retry_limit),
+	ATTR_LIST(inode_readahead_blks),
+	ATTR_LIST(inode_goal),
+	ATTR_LIST(mb_stats),
+	ATTR_LIST(mb_max_to_scan),
+	ATTR_LIST(mb_min_to_scan),
+	ATTR_LIST(mb_order2_req),
+	ATTR_LIST(mb_stream_req),
+	ATTR_LIST(mb_group_prealloc),
+	ATTR_LIST(mb_max_inode_prealloc),
+	ATTR_LIST(max_writeback_mb_bump),
+	ATTR_LIST(extent_max_zeroout_kb),
+	ATTR_LIST(trigger_fs_error),
+	ATTR_LIST(err_ratelimit_interval_ms),
+	ATTR_LIST(err_ratelimit_burst),
+	ATTR_LIST(warning_ratelimit_interval_ms),
+	ATTR_LIST(warning_ratelimit_burst),
+	ATTR_LIST(msg_ratelimit_interval_ms),
+	ATTR_LIST(msg_ratelimit_burst),
+	ATTR_LIST(errors_count),
+	ATTR_LIST(warning_count),
+	ATTR_LIST(msg_count),
+	ATTR_LIST(first_error_ino),
+	ATTR_LIST(last_error_ino),
+	ATTR_LIST(first_error_block),
+	ATTR_LIST(last_error_block),
+	ATTR_LIST(first_error_line),
+	ATTR_LIST(last_error_line),
+	ATTR_LIST(first_error_func),
+	ATTR_LIST(last_error_func),
+	ATTR_LIST(first_error_errcode),
+	ATTR_LIST(last_error_errcode),
+	ATTR_LIST(first_error_time),
+	ATTR_LIST(last_error_time),
+	ATTR_LIST(journal_task),
+#ifdef CONFIG_EXT4_DEBUG
+	ATTR_LIST(simulate_fail),
+#endif
+	ATTR_LIST(mb_prefetch),
+	ATTR_LIST(mb_prefetch_limit),
+	NULL,
+};
+ATTRIBUTE_GROUPS(ext4);
+
+/* Features this copy of ext4 supports */
+EXT4_ATTR_FEATURE(lazy_itable_init);
+EXT4_ATTR_FEATURE(batched_discard);
+EXT4_ATTR_FEATURE(meta_bg_resize);
+#ifdef CONFIG_FS_ENCRYPTION
+EXT4_ATTR_FEATURE(encryption);
+EXT4_ATTR_FEATURE(test_dummy_encryption_v2);
+#endif
+#ifdef CONFIG_UNICODE
+EXT4_ATTR_FEATURE(casefold);
+#endif
+#ifdef CONFIG_FS_VERITY
+EXT4_ATTR_FEATURE(verity);
+#endif
+EXT4_ATTR_FEATURE(metadata_csum_seed);
+EXT4_ATTR_FEATURE(fast_commit);
+
+static struct attribute *ext4_feat_attrs[] = {
+	ATTR_LIST(lazy_itable_init),
+	ATTR_LIST(batched_discard),
+	ATTR_LIST(meta_bg_resize),
+#ifdef CONFIG_FS_ENCRYPTION
+	ATTR_LIST(encryption),
+	ATTR_LIST(test_dummy_encryption_v2),
+#endif
+#ifdef CONFIG_UNICODE
+	ATTR_LIST(casefold),
+#endif
+#ifdef CONFIG_FS_VERITY
+	ATTR_LIST(verity),
+#endif
+	ATTR_LIST(metadata_csum_seed),
+	ATTR_LIST(fast_commit),
+	NULL,
+};
+ATTRIBUTE_GROUPS(ext4_feat);
+
+static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
+{
+	switch (a->attr_ptr) {
+	case ptr_explicit:
+		return a->u.explicit_ptr;
+	case ptr_ext4_sb_info_offset:
+		return (void *) (((char *) sbi) + a->u.offset);
+	case ptr_ext4_super_block_offset:
+		return (void *) (((char *) sbi->s_es) + a->u.offset);
+	}
+	return NULL;
+}
+
+static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
+{
+	return snprintf(buf, PAGE_SIZE, "%lld\n",
+			((time64_t)hi << 32) + le32_to_cpu(lo));
+}
+
+#define print_tstamp(buf, es, tstamp) \
+	__print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
+
+static ssize_t ext4_attr_show(struct kobject *kobj,
+			      struct attribute *attr, char *buf)
+{
+	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+						s_kobj);
+	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
+	void *ptr = calc_ptr(a, sbi);
+
+	switch (a->attr_id) {
+	case attr_delayed_allocation_blocks:
+		return snprintf(buf, PAGE_SIZE, "%llu\n",
+				(s64) EXT4_C2B(sbi,
+		       percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
+	case attr_session_write_kbytes:
+		return session_write_kbytes_show(sbi, buf);
+	case attr_lifetime_write_kbytes:
+		return lifetime_write_kbytes_show(sbi, buf);
+	case attr_reserved_clusters:
+		return snprintf(buf, PAGE_SIZE, "%llu\n",
+				(unsigned long long)
+				atomic64_read(&sbi->s_resv_clusters));
+	case attr_sra_exceeded_retry_limit:
+		return snprintf(buf, PAGE_SIZE, "%llu\n",
+				(unsigned long long)
+			percpu_counter_sum(&sbi->s_sra_exceeded_retry_limit));
+	case attr_inode_readahead:
+	case attr_pointer_ui:
+		if (!ptr)
+			return 0;
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			return snprintf(buf, PAGE_SIZE, "%u\n",
+					le32_to_cpup(ptr));
+		else
+			return snprintf(buf, PAGE_SIZE, "%u\n",
+					*((unsigned int *) ptr));
+	case attr_pointer_ul:
+		if (!ptr)
+			return 0;
+		return snprintf(buf, PAGE_SIZE, "%lu\n",
+				*((unsigned long *) ptr));
+	case attr_pointer_u8:
+		if (!ptr)
+			return 0;
+		return snprintf(buf, PAGE_SIZE, "%u\n",
+				*((unsigned char *) ptr));
+	case attr_pointer_u64:
+		if (!ptr)
+			return 0;
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			return snprintf(buf, PAGE_SIZE, "%llu\n",
+					le64_to_cpup(ptr));
+		else
+			return snprintf(buf, PAGE_SIZE, "%llu\n",
+					*((unsigned long long *) ptr));
+	case attr_pointer_string:
+		if (!ptr)
+			return 0;
+		return snprintf(buf, PAGE_SIZE, "%.*s\n", a->attr_size,
+				(char *) ptr);
+	case attr_pointer_atomic:
+		if (!ptr)
+			return 0;
+		return snprintf(buf, PAGE_SIZE, "%d\n",
+				atomic_read((atomic_t *) ptr));
+	case attr_feature:
+		return snprintf(buf, PAGE_SIZE, "supported\n");
+	case attr_first_error_time:
+		return print_tstamp(buf, sbi->s_es, s_first_error_time);
+	case attr_last_error_time:
+		return print_tstamp(buf, sbi->s_es, s_last_error_time);
+	case attr_journal_task:
+		return journal_task_show(sbi, buf);
+	}
+
+	return 0;
+}
+
+static ssize_t ext4_attr_store(struct kobject *kobj,
+			       struct attribute *attr,
+			       const char *buf, size_t len)
+{
+	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+						s_kobj);
+	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
+	void *ptr = calc_ptr(a, sbi);
+	unsigned long t;
+	int ret;
+
+	switch (a->attr_id) {
+	case attr_reserved_clusters:
+		return reserved_clusters_store(sbi, buf, len);
+	case attr_pointer_ui:
+		if (!ptr)
+			return 0;
+		ret = kstrtoul(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			*((__le32 *) ptr) = cpu_to_le32(t);
+		else
+			*((unsigned int *) ptr) = t;
+		return len;
+	case attr_pointer_ul:
+		if (!ptr)
+			return 0;
+		ret = kstrtoul(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		*((unsigned long *) ptr) = t;
+		return len;
+	case attr_inode_readahead:
+		return inode_readahead_blks_store(sbi, buf, len);
+	case attr_trigger_test_error:
+		return trigger_test_error(sbi, buf, len);
+	}
+	return 0;
+}
+
+static void ext4_sb_release(struct kobject *kobj)
+{
+	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+						s_kobj);
+	complete(&sbi->s_kobj_unregister);
+}
+
+static void ext4_feat_release(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static const struct sysfs_ops ext4_attr_ops = {
+	.show	= ext4_attr_show,
+	.store	= ext4_attr_store,
+};
+
+static struct kobj_type ext4_sb_ktype = {
+	.default_groups = ext4_groups,
+	.sysfs_ops	= &ext4_attr_ops,
+	.release	= ext4_sb_release,
+};
+
+static struct kobj_type ext4_feat_ktype = {
+	.default_groups = ext4_feat_groups,
+	.sysfs_ops	= &ext4_attr_ops,
+	.release	= ext4_feat_release,
+};
+
+static struct kobject *ext4_root;
+
+static struct kobject *ext4_feat;
+
+int ext4_register_sysfs(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int err;
+
+	init_completion(&sbi->s_kobj_unregister);
+	err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
+				   "%s", sb->s_id);
+	if (err) {
+		kobject_put(&sbi->s_kobj);
+		wait_for_completion(&sbi->s_kobj_unregister);
+		return err;
+	}
+
+	if (ext4_proc_root)
+		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
+	if (sbi->s_proc) {
+		proc_create_single_data("options", S_IRUGO, sbi->s_proc,
+				ext4_seq_options_show, sb);
+		proc_create_single_data("es_shrinker_info", S_IRUGO,
+				sbi->s_proc, ext4_seq_es_shrinker_info_show,
+				sb);
+		proc_create_single_data("fc_info", 0444, sbi->s_proc,
+					ext4_fc_info_show, sb);
+		proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
+				&ext4_mb_seq_groups_ops, sb);
+		proc_create_single_data("mb_stats", 0444, sbi->s_proc,
+				ext4_seq_mb_stats_show, sb);
+	}
+	return 0;
+}
+
+void ext4_unregister_sysfs(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (sbi->s_proc)
+		remove_proc_subtree(sb->s_id, ext4_proc_root);
+	kobject_del(&sbi->s_kobj);
+}
+
+int __init ext4_init_sysfs(void)
+{
+	int ret;
+
+	ext4_root = kobject_create_and_add("ext4", fs_kobj);
+	if (!ext4_root)
+		return -ENOMEM;
+
+	ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
+	if (!ext4_feat) {
+		ret = -ENOMEM;
+		goto root_err;
+	}
+
+	ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
+				   ext4_root, "features");
+	if (ret)
+		goto feat_err;
+
+	ext4_proc_root = proc_mkdir(proc_dirname, NULL);
+	return ret;
+
+feat_err:
+	kobject_put(ext4_feat);
+	ext4_feat = NULL;
+root_err:
+	kobject_put(ext4_root);
+	ext4_root = NULL;
+	return ret;
+}
+
+void ext4_exit_sysfs(void)
+{
+	kobject_put(ext4_feat);
+	ext4_feat = NULL;
+	kobject_put(ext4_root);
+	ext4_root = NULL;
+	remove_proc_entry(proc_dirname, NULL);
+	ext4_proc_root = NULL;
+}
+
diff --git a/fs/ext4/truncate.h b/fs/ext4/truncate.h
new file mode 100644
index 000000000..bcbe3668c
--- /dev/null
+++ b/fs/ext4/truncate.h
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/truncate.h
+ *
+ * Common inline functions needed for truncate support
+ */
+
+/*
+ * Truncate blocks that were not used by write. We have to truncate the
+ * pagecache as well so that corresponding buffers get properly unmapped.
+ */
+static inline void ext4_truncate_failed_write(struct inode *inode)
+{
+	/*
+	 * We don't need to call ext4_break_layouts() because the blocks we
+	 * are truncating were never visible to userspace.
+	 */
+	down_write(&EXT4_I(inode)->i_mmap_sem);
+	truncate_inode_pages(inode->i_mapping, inode->i_size);
+	ext4_truncate(inode);
+	up_write(&EXT4_I(inode)->i_mmap_sem);
+}
+
+/*
+ * Work out how many blocks we need to proceed with the next chunk of a
+ * truncate transaction.
+ */
+static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
+{
+	ext4_lblk_t needed;
+
+	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
+
+	/* Give ourselves just enough room to cope with inodes in which
+	 * i_blocks is corrupt: we've seen disk corruptions in the past
+	 * which resulted in random data in an inode which looked enough
+	 * like a regular file for ext4 to try to delete it.  Things
+	 * will go a bit crazy if that happens, but at least we should
+	 * try not to panic the whole kernel. */
+	if (needed < 2)
+		needed = 2;
+
+	/* But we need to bound the transaction so we don't overflow the
+	 * journal. */
+	if (needed > EXT4_MAX_TRANS_DATA)
+		needed = EXT4_MAX_TRANS_DATA;
+
+	return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
+}
+
diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c
new file mode 100644
index 000000000..e3019f920
--- /dev/null
+++ b/fs/ext4/verity.c
@@ -0,0 +1,401 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/ext4/verity.c: fs-verity support for ext4
+ *
+ * Copyright 2019 Google LLC
+ */
+
+/*
+ * Implementation of fsverity_operations for ext4.
+ *
+ * ext4 stores the verity metadata (Merkle tree and fsverity_descriptor) past
+ * the end of the file, starting at the first 64K boundary beyond i_size.  This
+ * approach works because (a) verity files are readonly, and (b) pages fully
+ * beyond i_size aren't visible to userspace but can be read/written internally
+ * by ext4 with only some relatively small changes to ext4.  This approach
+ * avoids having to depend on the EA_INODE feature and on rearchitecturing
+ * ext4's xattr support to support paging multi-gigabyte xattrs into memory, and
+ * to support encrypting xattrs.  Note that the verity metadata *must* be
+ * encrypted when the file is, since it contains hashes of the plaintext data.
+ *
+ * Using a 64K boundary rather than a 4K one keeps things ready for
+ * architectures with 64K pages, and it doesn't necessarily waste space on-disk
+ * since there can be a hole between i_size and the start of the Merkle tree.
+ */
+
+#include <linux/quotaops.h>
+
+#include "ext4.h"
+#include "ext4_extents.h"
+#include "ext4_jbd2.h"
+
+static inline loff_t ext4_verity_metadata_pos(const struct inode *inode)
+{
+	return round_up(inode->i_size, 65536);
+}
+
+/*
+ * Read some verity metadata from the inode.  __vfs_read() can't be used because
+ * we need to read beyond i_size.
+ */
+static int pagecache_read(struct inode *inode, void *buf, size_t count,
+			  loff_t pos)
+{
+	while (count) {
+		size_t n = min_t(size_t, count,
+				 PAGE_SIZE - offset_in_page(pos));
+		struct page *page;
+		void *addr;
+
+		page = read_mapping_page(inode->i_mapping, pos >> PAGE_SHIFT,
+					 NULL);
+		if (IS_ERR(page))
+			return PTR_ERR(page);
+
+		addr = kmap_atomic(page);
+		memcpy(buf, addr + offset_in_page(pos), n);
+		kunmap_atomic(addr);
+
+		put_page(page);
+
+		buf += n;
+		pos += n;
+		count -= n;
+	}
+	return 0;
+}
+
+/*
+ * Write some verity metadata to the inode for FS_IOC_ENABLE_VERITY.
+ * kernel_write() can't be used because the file descriptor is readonly.
+ */
+static int pagecache_write(struct inode *inode, const void *buf, size_t count,
+			   loff_t pos)
+{
+	if (pos + count > inode->i_sb->s_maxbytes)
+		return -EFBIG;
+
+	while (count) {
+		size_t n = min_t(size_t, count,
+				 PAGE_SIZE - offset_in_page(pos));
+		struct page *page;
+		void *fsdata = NULL;
+		int res;
+
+		res = pagecache_write_begin(NULL, inode->i_mapping, pos, n, 0,
+					    &page, &fsdata);
+		if (res)
+			return res;
+
+		memcpy_to_page(page, offset_in_page(pos), buf, n);
+
+		res = pagecache_write_end(NULL, inode->i_mapping, pos, n, n,
+					  page, fsdata);
+		if (res < 0)
+			return res;
+		if (res != n)
+			return -EIO;
+
+		buf += n;
+		pos += n;
+		count -= n;
+	}
+	return 0;
+}
+
+static int ext4_begin_enable_verity(struct file *filp)
+{
+	struct inode *inode = file_inode(filp);
+	const int credits = 2; /* superblock and inode for ext4_orphan_add() */
+	handle_t *handle;
+	int err;
+
+	if (IS_DAX(inode) || ext4_test_inode_flag(inode, EXT4_INODE_DAX))
+		return -EINVAL;
+
+	if (ext4_verity_in_progress(inode))
+		return -EBUSY;
+
+	/*
+	 * Since the file was opened readonly, we have to initialize the jbd
+	 * inode and quotas here and not rely on ->open() doing it.  This must
+	 * be done before evicting the inline data.
+	 */
+
+	err = ext4_inode_attach_jinode(inode);
+	if (err)
+		return err;
+
+	err = dquot_initialize(inode);
+	if (err)
+		return err;
+
+	err = ext4_convert_inline_data(inode);
+	if (err)
+		return err;
+
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		ext4_warning_inode(inode,
+				   "verity is only allowed on extent-based files");
+		return -EOPNOTSUPP;
+	}
+
+	/*
+	 * ext4 uses the last allocated block to find the verity descriptor, so
+	 * we must remove any other blocks past EOF which might confuse things.
+	 */
+	err = ext4_truncate(inode);
+	if (err)
+		return err;
+
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, credits);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	err = ext4_orphan_add(handle, inode);
+	if (err == 0)
+		ext4_set_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS);
+
+	ext4_journal_stop(handle);
+	return err;
+}
+
+/*
+ * ext4 stores the verity descriptor beginning on the next filesystem block
+ * boundary after the Merkle tree.  Then, the descriptor size is stored in the
+ * last 4 bytes of the last allocated filesystem block --- which is either the
+ * block in which the descriptor ends, or the next block after that if there
+ * weren't at least 4 bytes remaining.
+ *
+ * We can't simply store the descriptor in an xattr because it *must* be
+ * encrypted when ext4 encryption is used, but ext4 encryption doesn't encrypt
+ * xattrs.  Also, if the descriptor includes a large signature blob it may be
+ * too large to store in an xattr without the EA_INODE feature.
+ */
+static int ext4_write_verity_descriptor(struct inode *inode, const void *desc,
+					size_t desc_size, u64 merkle_tree_size)
+{
+	const u64 desc_pos = round_up(ext4_verity_metadata_pos(inode) +
+				      merkle_tree_size, i_blocksize(inode));
+	const u64 desc_end = desc_pos + desc_size;
+	const __le32 desc_size_disk = cpu_to_le32(desc_size);
+	const u64 desc_size_pos = round_up(desc_end + sizeof(desc_size_disk),
+					   i_blocksize(inode)) -
+				  sizeof(desc_size_disk);
+	int err;
+
+	err = pagecache_write(inode, desc, desc_size, desc_pos);
+	if (err)
+		return err;
+
+	return pagecache_write(inode, &desc_size_disk, sizeof(desc_size_disk),
+			       desc_size_pos);
+}
+
+static int ext4_end_enable_verity(struct file *filp, const void *desc,
+				  size_t desc_size, u64 merkle_tree_size)
+{
+	struct inode *inode = file_inode(filp);
+	const int credits = 2; /* superblock and inode for ext4_orphan_del() */
+	handle_t *handle;
+	struct ext4_iloc iloc;
+	int err = 0;
+
+	/*
+	 * If an error already occurred (which fs/verity/ signals by passing
+	 * desc == NULL), then only clean-up is needed.
+	 */
+	if (desc == NULL)
+		goto cleanup;
+
+	/* Append the verity descriptor. */
+	err = ext4_write_verity_descriptor(inode, desc, desc_size,
+					   merkle_tree_size);
+	if (err)
+		goto cleanup;
+
+	/*
+	 * Write all pages (both data and verity metadata).  Note that this must
+	 * happen before clearing EXT4_STATE_VERITY_IN_PROGRESS; otherwise pages
+	 * beyond i_size won't be written properly.  For crash consistency, this
+	 * also must happen before the verity inode flag gets persisted.
+	 */
+	err = filemap_write_and_wait(inode->i_mapping);
+	if (err)
+		goto cleanup;
+
+	/*
+	 * Finally, set the verity inode flag and remove the inode from the
+	 * orphan list (in a single transaction).
+	 */
+
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, credits);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		goto cleanup;
+	}
+
+	err = ext4_orphan_del(handle, inode);
+	if (err)
+		goto stop_and_cleanup;
+
+	err = ext4_reserve_inode_write(handle, inode, &iloc);
+	if (err)
+		goto stop_and_cleanup;
+
+	ext4_set_inode_flag(inode, EXT4_INODE_VERITY);
+	ext4_set_inode_flags(inode, false);
+	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+	if (err)
+		goto stop_and_cleanup;
+
+	ext4_journal_stop(handle);
+
+	ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS);
+	return 0;
+
+stop_and_cleanup:
+	ext4_journal_stop(handle);
+cleanup:
+	/*
+	 * Verity failed to be enabled, so clean up by truncating any verity
+	 * metadata that was written beyond i_size (both from cache and from
+	 * disk), removing the inode from the orphan list (if it wasn't done
+	 * already), and clearing EXT4_STATE_VERITY_IN_PROGRESS.
+	 */
+	truncate_inode_pages(inode->i_mapping, inode->i_size);
+	ext4_truncate(inode);
+	ext4_orphan_del(NULL, inode);
+	ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS);
+	return err;
+}
+
+static int ext4_get_verity_descriptor_location(struct inode *inode,
+					       size_t *desc_size_ret,
+					       u64 *desc_pos_ret)
+{
+	struct ext4_ext_path *path;
+	struct ext4_extent *last_extent;
+	u32 end_lblk;
+	u64 desc_size_pos;
+	__le32 desc_size_disk;
+	u32 desc_size;
+	u64 desc_pos;
+	int err;
+
+	/*
+	 * Descriptor size is in last 4 bytes of last allocated block.
+	 * See ext4_write_verity_descriptor().
+	 */
+
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		EXT4_ERROR_INODE(inode, "verity file doesn't use extents");
+		return -EFSCORRUPTED;
+	}
+
+	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	last_extent = path[path->p_depth].p_ext;
+	if (!last_extent) {
+		EXT4_ERROR_INODE(inode, "verity file has no extents");
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		return -EFSCORRUPTED;
+	}
+
+	end_lblk = le32_to_cpu(last_extent->ee_block) +
+		   ext4_ext_get_actual_len(last_extent);
+	desc_size_pos = (u64)end_lblk << inode->i_blkbits;
+	ext4_ext_drop_refs(path);
+	kfree(path);
+
+	if (desc_size_pos < sizeof(desc_size_disk))
+		goto bad;
+	desc_size_pos -= sizeof(desc_size_disk);
+
+	err = pagecache_read(inode, &desc_size_disk, sizeof(desc_size_disk),
+			     desc_size_pos);
+	if (err)
+		return err;
+	desc_size = le32_to_cpu(desc_size_disk);
+
+	/*
+	 * The descriptor is stored just before the desc_size_disk, but starting
+	 * on a filesystem block boundary.
+	 */
+
+	if (desc_size > INT_MAX || desc_size > desc_size_pos)
+		goto bad;
+
+	desc_pos = round_down(desc_size_pos - desc_size, i_blocksize(inode));
+	if (desc_pos < ext4_verity_metadata_pos(inode))
+		goto bad;
+
+	*desc_size_ret = desc_size;
+	*desc_pos_ret = desc_pos;
+	return 0;
+
+bad:
+	EXT4_ERROR_INODE(inode, "verity file corrupted; can't find descriptor");
+	return -EFSCORRUPTED;
+}
+
+static int ext4_get_verity_descriptor(struct inode *inode, void *buf,
+				      size_t buf_size)
+{
+	size_t desc_size = 0;
+	u64 desc_pos = 0;
+	int err;
+
+	err = ext4_get_verity_descriptor_location(inode, &desc_size, &desc_pos);
+	if (err)
+		return err;
+
+	if (buf_size) {
+		if (desc_size > buf_size)
+			return -ERANGE;
+		err = pagecache_read(inode, buf, desc_size, desc_pos);
+		if (err)
+			return err;
+	}
+	return desc_size;
+}
+
+static struct page *ext4_read_merkle_tree_page(struct inode *inode,
+					       pgoff_t index,
+					       unsigned long num_ra_pages)
+{
+	struct page *page;
+
+	index += ext4_verity_metadata_pos(inode) >> PAGE_SHIFT;
+
+	page = find_get_page_flags(inode->i_mapping, index, FGP_ACCESSED);
+	if (!page || !PageUptodate(page)) {
+		DEFINE_READAHEAD(ractl, NULL, inode->i_mapping, index);
+
+		if (page)
+			put_page(page);
+		else if (num_ra_pages > 1)
+			page_cache_ra_unbounded(&ractl, num_ra_pages, 0);
+		page = read_mapping_page(inode->i_mapping, index, NULL);
+	}
+	return page;
+}
+
+static int ext4_write_merkle_tree_block(struct inode *inode, const void *buf,
+					u64 index, int log_blocksize)
+{
+	loff_t pos = ext4_verity_metadata_pos(inode) + (index << log_blocksize);
+
+	return pagecache_write(inode, buf, 1 << log_blocksize, pos);
+}
+
+const struct fsverity_operations ext4_verityops = {
+	.begin_enable_verity	= ext4_begin_enable_verity,
+	.end_enable_verity	= ext4_end_enable_verity,
+	.get_verity_descriptor	= ext4_get_verity_descriptor,
+	.read_merkle_tree_page	= ext4_read_merkle_tree_page,
+	.write_merkle_tree_block = ext4_write_merkle_tree_block,
+};
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
new file mode 100644
index 000000000..5bf858fc2
--- /dev/null
+++ b/fs/ext4/xattr.c
@@ -0,0 +1,3154 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/xattr.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ *
+ * Fix by Harrison Xing <harrison@mountainviewdata.com>.
+ * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
+ * Extended attributes for symlinks and special files added per
+ *  suggestion of Luka Renko <luka.renko@hermes.si>.
+ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
+ *  Red Hat Inc.
+ * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
+ *  and Andreas Gruenbacher <agruen@suse.de>.
+ */
+
+/*
+ * Extended attributes are stored directly in inodes (on file systems with
+ * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
+ * field contains the block number if an inode uses an additional block. All
+ * attributes must fit in the inode and one additional block. Blocks that
+ * contain the identical set of attributes may be shared among several inodes.
+ * Identical blocks are detected by keeping a cache of blocks that have
+ * recently been accessed.
+ *
+ * The attributes in inodes and on blocks have a different header; the entries
+ * are stored in the same format:
+ *
+ *   +------------------+
+ *   | header           |
+ *   | entry 1          | |
+ *   | entry 2          | | growing downwards
+ *   | entry 3          | v
+ *   | four null bytes  |
+ *   | . . .            |
+ *   | value 1          | ^
+ *   | value 3          | | growing upwards
+ *   | value 2          | |
+ *   +------------------+
+ *
+ * The header is followed by multiple entry descriptors. In disk blocks, the
+ * entry descriptors are kept sorted. In inodes, they are unsorted. The
+ * attribute values are aligned to the end of the block in no specific order.
+ *
+ * Locking strategy
+ * ----------------
+ * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
+ * EA blocks are only changed if they are exclusive to an inode, so
+ * holding xattr_sem also means that nothing but the EA block's reference
+ * count can change. Multiple writers to the same block are synchronized
+ * by the buffer lock.
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/mbcache.h>
+#include <linux/quotaops.h>
+#include <linux/iversion.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+#include "acl.h"
+
+#ifdef EXT4_XATTR_DEBUG
+# define ea_idebug(inode, fmt, ...)					\
+	printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",			\
+	       inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
+# define ea_bdebug(bh, fmt, ...)					\
+	printk(KERN_DEBUG "block %pg:%lu: " fmt "\n",			\
+	       bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
+#else
+# define ea_idebug(inode, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+# define ea_bdebug(bh, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+#endif
+
+static void ext4_xattr_block_cache_insert(struct mb_cache *,
+					  struct buffer_head *);
+static struct buffer_head *
+ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
+			    struct mb_cache_entry **);
+static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
+				    size_t value_count);
+static void ext4_xattr_rehash(struct ext4_xattr_header *);
+
+static const struct xattr_handler * const ext4_xattr_handler_map[] = {
+	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+	[EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
+	[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
+#endif
+	[EXT4_XATTR_INDEX_TRUSTED]	     = &ext4_xattr_trusted_handler,
+#ifdef CONFIG_EXT4_FS_SECURITY
+	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
+#endif
+	[EXT4_XATTR_INDEX_HURD]		     = &ext4_xattr_hurd_handler,
+};
+
+const struct xattr_handler *ext4_xattr_handlers[] = {
+	&ext4_xattr_user_handler,
+	&ext4_xattr_trusted_handler,
+#ifdef CONFIG_EXT4_FS_POSIX_ACL
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+#endif
+#ifdef CONFIG_EXT4_FS_SECURITY
+	&ext4_xattr_security_handler,
+#endif
+	&ext4_xattr_hurd_handler,
+	NULL
+};
+
+#define EA_BLOCK_CACHE(inode)	(((struct ext4_sb_info *) \
+				inode->i_sb->s_fs_info)->s_ea_block_cache)
+
+#define EA_INODE_CACHE(inode)	(((struct ext4_sb_info *) \
+				inode->i_sb->s_fs_info)->s_ea_inode_cache)
+
+static int
+ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
+			struct inode *inode);
+
+#ifdef CONFIG_LOCKDEP
+void ext4_xattr_inode_set_class(struct inode *ea_inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(ea_inode);
+
+	lockdep_set_subclass(&ea_inode->i_rwsem, 1);
+	(void) ei;	/* shut up clang warning if !CONFIG_LOCKDEP */
+	lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
+}
+#endif
+
+static __le32 ext4_xattr_block_csum(struct inode *inode,
+				    sector_t block_nr,
+				    struct ext4_xattr_header *hdr)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	__u32 csum;
+	__le64 dsk_block_nr = cpu_to_le64(block_nr);
+	__u32 dummy_csum = 0;
+	int offset = offsetof(struct ext4_xattr_header, h_checksum);
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
+			   sizeof(dsk_block_nr));
+	csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
+	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
+	offset += sizeof(dummy_csum);
+	csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
+			   EXT4_BLOCK_SIZE(inode->i_sb) - offset);
+
+	return cpu_to_le32(csum);
+}
+
+static int ext4_xattr_block_csum_verify(struct inode *inode,
+					struct buffer_head *bh)
+{
+	struct ext4_xattr_header *hdr = BHDR(bh);
+	int ret = 1;
+
+	if (ext4_has_metadata_csum(inode->i_sb)) {
+		lock_buffer(bh);
+		ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
+							bh->b_blocknr, hdr));
+		unlock_buffer(bh);
+	}
+	return ret;
+}
+
+static void ext4_xattr_block_csum_set(struct inode *inode,
+				      struct buffer_head *bh)
+{
+	if (ext4_has_metadata_csum(inode->i_sb))
+		BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
+						bh->b_blocknr, BHDR(bh));
+}
+
+static inline const struct xattr_handler *
+ext4_xattr_handler(int name_index)
+{
+	const struct xattr_handler *handler = NULL;
+
+	if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
+		handler = ext4_xattr_handler_map[name_index];
+	return handler;
+}
+
+static int
+ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
+			 void *value_start)
+{
+	struct ext4_xattr_entry *e = entry;
+
+	/* Find the end of the names list */
+	while (!IS_LAST_ENTRY(e)) {
+		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
+		if ((void *)next >= end)
+			return -EFSCORRUPTED;
+		if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
+			return -EFSCORRUPTED;
+		e = next;
+	}
+
+	/* Check the values */
+	while (!IS_LAST_ENTRY(entry)) {
+		u32 size = le32_to_cpu(entry->e_value_size);
+
+		if (size > EXT4_XATTR_SIZE_MAX)
+			return -EFSCORRUPTED;
+
+		if (size != 0 && entry->e_value_inum == 0) {
+			u16 offs = le16_to_cpu(entry->e_value_offs);
+			void *value;
+
+			/*
+			 * The value cannot overlap the names, and the value
+			 * with padding cannot extend beyond 'end'.  Check both
+			 * the padded and unpadded sizes, since the size may
+			 * overflow to 0 when adding padding.
+			 */
+			if (offs > end - value_start)
+				return -EFSCORRUPTED;
+			value = value_start + offs;
+			if (value < (void *)e + sizeof(u32) ||
+			    size > end - value ||
+			    EXT4_XATTR_SIZE(size) > end - value)
+				return -EFSCORRUPTED;
+		}
+		entry = EXT4_XATTR_NEXT(entry);
+	}
+
+	return 0;
+}
+
+static inline int
+__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
+			 const char *function, unsigned int line)
+{
+	int error = -EFSCORRUPTED;
+
+	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
+	    BHDR(bh)->h_blocks != cpu_to_le32(1))
+		goto errout;
+	if (buffer_verified(bh))
+		return 0;
+
+	error = -EFSBADCRC;
+	if (!ext4_xattr_block_csum_verify(inode, bh))
+		goto errout;
+	error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
+					 bh->b_data);
+errout:
+	if (error)
+		__ext4_error_inode(inode, function, line, 0, -error,
+				   "corrupted xattr block %llu",
+				   (unsigned long long) bh->b_blocknr);
+	else
+		set_buffer_verified(bh);
+	return error;
+}
+
+#define ext4_xattr_check_block(inode, bh) \
+	__ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
+
+
+static int
+__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
+			 void *end, const char *function, unsigned int line)
+{
+	int error = -EFSCORRUPTED;
+
+	if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
+	    (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
+		goto errout;
+	error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
+errout:
+	if (error)
+		__ext4_error_inode(inode, function, line, 0, -error,
+				   "corrupted in-inode xattr");
+	return error;
+}
+
+#define xattr_check_inode(inode, header, end) \
+	__xattr_check_inode((inode), (header), (end), __func__, __LINE__)
+
+static int
+xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
+		 void *end, int name_index, const char *name, int sorted)
+{
+	struct ext4_xattr_entry *entry, *next;
+	size_t name_len;
+	int cmp = 1;
+
+	if (name == NULL)
+		return -EINVAL;
+	name_len = strlen(name);
+	for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
+		next = EXT4_XATTR_NEXT(entry);
+		if ((void *) next >= end) {
+			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
+			return -EFSCORRUPTED;
+		}
+		cmp = name_index - entry->e_name_index;
+		if (!cmp)
+			cmp = name_len - entry->e_name_len;
+		if (!cmp)
+			cmp = memcmp(name, entry->e_name, name_len);
+		if (cmp <= 0 && (sorted || cmp == 0))
+			break;
+	}
+	*pentry = entry;
+	return cmp ? -ENODATA : 0;
+}
+
+static u32
+ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
+{
+	return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
+}
+
+static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
+{
+	return ((u64)ea_inode->i_ctime.tv_sec << 32) |
+		(u32) inode_peek_iversion_raw(ea_inode);
+}
+
+static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
+{
+	ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
+	inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
+}
+
+static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
+{
+	return (u32)ea_inode->i_atime.tv_sec;
+}
+
+static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
+{
+	ea_inode->i_atime.tv_sec = hash;
+}
+
+/*
+ * Read the EA value from an inode.
+ */
+static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
+{
+	int blocksize = 1 << ea_inode->i_blkbits;
+	int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
+	int tail_size = (size % blocksize) ?: blocksize;
+	struct buffer_head *bhs_inline[8];
+	struct buffer_head **bhs = bhs_inline;
+	int i, ret;
+
+	if (bh_count > ARRAY_SIZE(bhs_inline)) {
+		bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
+		if (!bhs)
+			return -ENOMEM;
+	}
+
+	ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
+			       true /* wait */, bhs);
+	if (ret)
+		goto free_bhs;
+
+	for (i = 0; i < bh_count; i++) {
+		/* There shouldn't be any holes in ea_inode. */
+		if (!bhs[i]) {
+			ret = -EFSCORRUPTED;
+			goto put_bhs;
+		}
+		memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
+		       i < bh_count - 1 ? blocksize : tail_size);
+	}
+	ret = 0;
+put_bhs:
+	for (i = 0; i < bh_count; i++)
+		brelse(bhs[i]);
+free_bhs:
+	if (bhs != bhs_inline)
+		kfree(bhs);
+	return ret;
+}
+
+#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
+
+static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
+				 u32 ea_inode_hash, struct inode **ea_inode)
+{
+	struct inode *inode;
+	int err;
+
+	/*
+	 * We have to check for this corruption early as otherwise
+	 * iget_locked() could wait indefinitely for the state of our
+	 * parent inode.
+	 */
+	if (parent->i_ino == ea_ino) {
+		ext4_error(parent->i_sb,
+			   "Parent and EA inode have the same ino %lu", ea_ino);
+		return -EFSCORRUPTED;
+	}
+
+	inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		ext4_error(parent->i_sb,
+			   "error while reading EA inode %lu err=%d", ea_ino,
+			   err);
+		return err;
+	}
+	ext4_xattr_inode_set_class(inode);
+
+	/*
+	 * Check whether this is an old Lustre-style xattr inode. Lustre
+	 * implementation does not have hash validation, rather it has a
+	 * backpointer from ea_inode to the parent inode.
+	 */
+	if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
+	    EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
+	    inode->i_generation == parent->i_generation) {
+		ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
+		ext4_xattr_inode_set_ref(inode, 1);
+	} else {
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
+	*ea_inode = inode;
+	return 0;
+}
+
+/* Remove entry from mbcache when EA inode is getting evicted */
+void ext4_evict_ea_inode(struct inode *inode)
+{
+	struct mb_cache_entry *oe;
+
+	if (!EA_INODE_CACHE(inode))
+		return;
+	/* Wait for entry to get unused so that we can remove it */
+	while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
+			ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
+		mb_cache_entry_wait_unused(oe);
+		mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
+	}
+}
+
+static int
+ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
+			       struct ext4_xattr_entry *entry, void *buffer,
+			       size_t size)
+{
+	u32 hash;
+
+	/* Verify stored hash matches calculated hash. */
+	hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
+	if (hash != ext4_xattr_inode_get_hash(ea_inode))
+		return -EFSCORRUPTED;
+
+	if (entry) {
+		__le32 e_hash, tmp_data;
+
+		/* Verify entry hash. */
+		tmp_data = cpu_to_le32(hash);
+		e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
+					       &tmp_data, 1);
+		if (e_hash != entry->e_hash)
+			return -EFSCORRUPTED;
+	}
+	return 0;
+}
+
+/*
+ * Read xattr value from the EA inode.
+ */
+static int
+ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
+		     void *buffer, size_t size)
+{
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+	struct inode *ea_inode;
+	int err;
+
+	err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
+				    le32_to_cpu(entry->e_hash), &ea_inode);
+	if (err) {
+		ea_inode = NULL;
+		goto out;
+	}
+
+	if (i_size_read(ea_inode) != size) {
+		ext4_warning_inode(ea_inode,
+				   "ea_inode file size=%llu entry size=%zu",
+				   i_size_read(ea_inode), size);
+		err = -EFSCORRUPTED;
+		goto out;
+	}
+
+	err = ext4_xattr_inode_read(ea_inode, buffer, size);
+	if (err)
+		goto out;
+
+	if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
+		err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
+						     size);
+		if (err) {
+			ext4_warning_inode(ea_inode,
+					   "EA inode hash validation failed");
+			goto out;
+		}
+
+		if (ea_inode_cache)
+			mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
+					ext4_xattr_inode_get_hash(ea_inode),
+					ea_inode->i_ino, true /* reusable */);
+	}
+out:
+	iput(ea_inode);
+	return err;
+}
+
+static int
+ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
+		     void *buffer, size_t buffer_size)
+{
+	struct buffer_head *bh = NULL;
+	struct ext4_xattr_entry *entry;
+	size_t size;
+	void *end;
+	int error;
+	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
+
+	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
+		  name_index, name, buffer, (long)buffer_size);
+
+	if (!EXT4_I(inode)->i_file_acl)
+		return -ENODATA;
+	ea_idebug(inode, "reading block %llu",
+		  (unsigned long long)EXT4_I(inode)->i_file_acl);
+	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+	error = ext4_xattr_check_block(inode, bh);
+	if (error)
+		goto cleanup;
+	ext4_xattr_block_cache_insert(ea_block_cache, bh);
+	entry = BFIRST(bh);
+	end = bh->b_data + bh->b_size;
+	error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
+	if (error)
+		goto cleanup;
+	size = le32_to_cpu(entry->e_value_size);
+	error = -ERANGE;
+	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
+		goto cleanup;
+	if (buffer) {
+		if (size > buffer_size)
+			goto cleanup;
+		if (entry->e_value_inum) {
+			error = ext4_xattr_inode_get(inode, entry, buffer,
+						     size);
+			if (error)
+				goto cleanup;
+		} else {
+			u16 offset = le16_to_cpu(entry->e_value_offs);
+			void *p = bh->b_data + offset;
+
+			if (unlikely(p + size > end))
+				goto cleanup;
+			memcpy(buffer, p, size);
+		}
+	}
+	error = size;
+
+cleanup:
+	brelse(bh);
+	return error;
+}
+
+int
+ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
+		     void *buffer, size_t buffer_size)
+{
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_xattr_entry *entry;
+	struct ext4_inode *raw_inode;
+	struct ext4_iloc iloc;
+	size_t size;
+	void *end;
+	int error;
+
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
+		return -ENODATA;
+	error = ext4_get_inode_loc(inode, &iloc);
+	if (error)
+		return error;
+	raw_inode = ext4_raw_inode(&iloc);
+	header = IHDR(inode, raw_inode);
+	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+	error = xattr_check_inode(inode, header, end);
+	if (error)
+		goto cleanup;
+	entry = IFIRST(header);
+	error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
+	if (error)
+		goto cleanup;
+	size = le32_to_cpu(entry->e_value_size);
+	error = -ERANGE;
+	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
+		goto cleanup;
+	if (buffer) {
+		if (size > buffer_size)
+			goto cleanup;
+		if (entry->e_value_inum) {
+			error = ext4_xattr_inode_get(inode, entry, buffer,
+						     size);
+			if (error)
+				goto cleanup;
+		} else {
+			u16 offset = le16_to_cpu(entry->e_value_offs);
+			void *p = (void *)IFIRST(header) + offset;
+
+			if (unlikely(p + size > end))
+				goto cleanup;
+			memcpy(buffer, p, size);
+		}
+	}
+	error = size;
+
+cleanup:
+	brelse(iloc.bh);
+	return error;
+}
+
+/*
+ * ext4_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int
+ext4_xattr_get(struct inode *inode, int name_index, const char *name,
+	       void *buffer, size_t buffer_size)
+{
+	int error;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return -EIO;
+
+	if (strlen(name) > 255)
+		return -ERANGE;
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
+				     buffer_size);
+	if (error == -ENODATA)
+		error = ext4_xattr_block_get(inode, name_index, name, buffer,
+					     buffer_size);
+	up_read(&EXT4_I(inode)->xattr_sem);
+	return error;
+}
+
+static int
+ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
+			char *buffer, size_t buffer_size)
+{
+	size_t rest = buffer_size;
+
+	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
+		const struct xattr_handler *handler =
+			ext4_xattr_handler(entry->e_name_index);
+
+		if (handler && (!handler->list || handler->list(dentry))) {
+			const char *prefix = handler->prefix ?: handler->name;
+			size_t prefix_len = strlen(prefix);
+			size_t size = prefix_len + entry->e_name_len + 1;
+
+			if (buffer) {
+				if (size > rest)
+					return -ERANGE;
+				memcpy(buffer, prefix, prefix_len);
+				buffer += prefix_len;
+				memcpy(buffer, entry->e_name, entry->e_name_len);
+				buffer += entry->e_name_len;
+				*buffer++ = 0;
+			}
+			rest -= size;
+		}
+	}
+	return buffer_size - rest;  /* total size */
+}
+
+static int
+ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	struct inode *inode = d_inode(dentry);
+	struct buffer_head *bh = NULL;
+	int error;
+
+	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
+		  buffer, (long)buffer_size);
+
+	if (!EXT4_I(inode)->i_file_acl)
+		return 0;
+	ea_idebug(inode, "reading block %llu",
+		  (unsigned long long)EXT4_I(inode)->i_file_acl);
+	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+	error = ext4_xattr_check_block(inode, bh);
+	if (error)
+		goto cleanup;
+	ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
+	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
+					buffer_size);
+cleanup:
+	brelse(bh);
+	return error;
+}
+
+static int
+ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_inode *raw_inode;
+	struct ext4_iloc iloc;
+	void *end;
+	int error;
+
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
+		return 0;
+	error = ext4_get_inode_loc(inode, &iloc);
+	if (error)
+		return error;
+	raw_inode = ext4_raw_inode(&iloc);
+	header = IHDR(inode, raw_inode);
+	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+	error = xattr_check_inode(inode, header, end);
+	if (error)
+		goto cleanup;
+	error = ext4_xattr_list_entries(dentry, IFIRST(header),
+					buffer, buffer_size);
+
+cleanup:
+	brelse(iloc.bh);
+	return error;
+}
+
+/*
+ * Inode operation listxattr()
+ *
+ * d_inode(dentry)->i_rwsem: don't care
+ *
+ * Copy a list of attribute names into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+ssize_t
+ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	int ret, ret2;
+
+	down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
+	ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
+	if (ret < 0)
+		goto errout;
+	if (buffer) {
+		buffer += ret;
+		buffer_size -= ret;
+	}
+	ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
+	if (ret < 0)
+		goto errout;
+	ret += ret2;
+errout:
+	up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
+	return ret;
+}
+
+/*
+ * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
+ * not set, set it.
+ */
+static void ext4_xattr_update_super_block(handle_t *handle,
+					  struct super_block *sb)
+{
+	if (ext4_has_feature_xattr(sb))
+		return;
+
+	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
+	if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
+		ext4_set_feature_xattr(sb);
+		ext4_handle_dirty_super(handle, sb);
+	}
+}
+
+int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
+{
+	struct ext4_iloc iloc = { .bh = NULL };
+	struct buffer_head *bh = NULL;
+	struct ext4_inode *raw_inode;
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_xattr_entry *entry;
+	qsize_t ea_inode_refs = 0;
+	void *end;
+	int ret;
+
+	lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
+		ret = ext4_get_inode_loc(inode, &iloc);
+		if (ret)
+			goto out;
+		raw_inode = ext4_raw_inode(&iloc);
+		header = IHDR(inode, raw_inode);
+		end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+		ret = xattr_check_inode(inode, header, end);
+		if (ret)
+			goto out;
+
+		for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
+		     entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				ea_inode_refs++;
+	}
+
+	if (EXT4_I(inode)->i_file_acl) {
+		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+		if (IS_ERR(bh)) {
+			ret = PTR_ERR(bh);
+			bh = NULL;
+			goto out;
+		}
+
+		ret = ext4_xattr_check_block(inode, bh);
+		if (ret)
+			goto out;
+
+		for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
+		     entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				ea_inode_refs++;
+	}
+	*usage = ea_inode_refs + 1;
+	ret = 0;
+out:
+	brelse(iloc.bh);
+	brelse(bh);
+	return ret;
+}
+
+static inline size_t round_up_cluster(struct inode *inode, size_t length)
+{
+	struct super_block *sb = inode->i_sb;
+	size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
+				    inode->i_blkbits);
+	size_t mask = ~(cluster_size - 1);
+
+	return (length + cluster_size - 1) & mask;
+}
+
+static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
+{
+	int err;
+
+	err = dquot_alloc_inode(inode);
+	if (err)
+		return err;
+	err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
+	if (err)
+		dquot_free_inode(inode);
+	return err;
+}
+
+static void ext4_xattr_inode_free_quota(struct inode *parent,
+					struct inode *ea_inode,
+					size_t len)
+{
+	if (ea_inode &&
+	    ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
+		return;
+	dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
+	dquot_free_inode(parent);
+}
+
+int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
+			     struct buffer_head *block_bh, size_t value_len,
+			     bool is_create)
+{
+	int credits;
+	int blocks;
+
+	/*
+	 * 1) Owner inode update
+	 * 2) Ref count update on old xattr block
+	 * 3) new xattr block
+	 * 4) block bitmap update for new xattr block
+	 * 5) group descriptor for new xattr block
+	 * 6) block bitmap update for old xattr block
+	 * 7) group descriptor for old block
+	 *
+	 * 6 & 7 can happen if we have two racing threads T_a and T_b
+	 * which are each trying to set an xattr on inodes I_a and I_b
+	 * which were both initially sharing an xattr block.
+	 */
+	credits = 7;
+
+	/* Quota updates. */
+	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
+
+	/*
+	 * In case of inline data, we may push out the data to a block,
+	 * so we need to reserve credits for this eventuality
+	 */
+	if (inode && ext4_has_inline_data(inode))
+		credits += ext4_writepage_trans_blocks(inode) + 1;
+
+	/* We are done if ea_inode feature is not enabled. */
+	if (!ext4_has_feature_ea_inode(sb))
+		return credits;
+
+	/* New ea_inode, inode map, block bitmap, group descriptor. */
+	credits += 4;
+
+	/* Data blocks. */
+	blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+
+	/* Indirection block or one level of extent tree. */
+	blocks += 1;
+
+	/* Block bitmap and group descriptor updates for each block. */
+	credits += blocks * 2;
+
+	/* Blocks themselves. */
+	credits += blocks;
+
+	if (!is_create) {
+		/* Dereference ea_inode holding old xattr value.
+		 * Old ea_inode, inode map, block bitmap, group descriptor.
+		 */
+		credits += 4;
+
+		/* Data blocks for old ea_inode. */
+		blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
+
+		/* Indirection block or one level of extent tree for old
+		 * ea_inode.
+		 */
+		blocks += 1;
+
+		/* Block bitmap and group descriptor updates for each block. */
+		credits += blocks * 2;
+	}
+
+	/* We may need to clone the existing xattr block in which case we need
+	 * to increment ref counts for existing ea_inodes referenced by it.
+	 */
+	if (block_bh) {
+		struct ext4_xattr_entry *entry = BFIRST(block_bh);
+
+		for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				/* Ref count update on ea_inode. */
+				credits += 1;
+	}
+	return credits;
+}
+
+static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
+				       int ref_change)
+{
+	struct ext4_iloc iloc;
+	s64 ref_count;
+	int ret;
+
+	inode_lock(ea_inode);
+
+	ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
+	if (ret)
+		goto out;
+
+	ref_count = ext4_xattr_inode_get_ref(ea_inode);
+	ref_count += ref_change;
+	ext4_xattr_inode_set_ref(ea_inode, ref_count);
+
+	if (ref_change > 0) {
+		WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
+			  ea_inode->i_ino, ref_count);
+
+		if (ref_count == 1) {
+			WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
+				  ea_inode->i_ino, ea_inode->i_nlink);
+
+			set_nlink(ea_inode, 1);
+			ext4_orphan_del(handle, ea_inode);
+		}
+	} else {
+		WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
+			  ea_inode->i_ino, ref_count);
+
+		if (ref_count == 0) {
+			WARN_ONCE(ea_inode->i_nlink != 1,
+				  "EA inode %lu i_nlink=%u",
+				  ea_inode->i_ino, ea_inode->i_nlink);
+
+			clear_nlink(ea_inode);
+			ext4_orphan_add(handle, ea_inode);
+		}
+	}
+
+	ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
+	if (ret)
+		ext4_warning_inode(ea_inode,
+				   "ext4_mark_iloc_dirty() failed ret=%d", ret);
+out:
+	inode_unlock(ea_inode);
+	return ret;
+}
+
+static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
+{
+	return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
+}
+
+static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
+{
+	return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
+}
+
+static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
+					struct ext4_xattr_entry *first)
+{
+	struct inode *ea_inode;
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_entry *failed_entry;
+	unsigned int ea_ino;
+	int err, saved_err;
+
+	for (entry = first; !IS_LAST_ENTRY(entry);
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino,
+					    le32_to_cpu(entry->e_hash),
+					    &ea_inode);
+		if (err)
+			goto cleanup;
+		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode, "inc ref error %d", err);
+			iput(ea_inode);
+			goto cleanup;
+		}
+		iput(ea_inode);
+	}
+	return 0;
+
+cleanup:
+	saved_err = err;
+	failed_entry = entry;
+
+	for (entry = first; entry != failed_entry;
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino,
+					    le32_to_cpu(entry->e_hash),
+					    &ea_inode);
+		if (err) {
+			ext4_warning(parent->i_sb,
+				     "cleanup ea_ino %u iget error %d", ea_ino,
+				     err);
+			continue;
+		}
+		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (err)
+			ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
+					   err);
+		iput(ea_inode);
+	}
+	return saved_err;
+}
+
+static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
+			struct buffer_head *bh, bool block_csum, bool dirty)
+{
+	int error;
+
+	if (bh && dirty) {
+		if (block_csum)
+			ext4_xattr_block_csum_set(inode, bh);
+		error = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (error) {
+			ext4_warning(inode->i_sb, "Handle metadata (error %d)",
+				     error);
+			return error;
+		}
+	}
+	return 0;
+}
+
+static void
+ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
+			     struct buffer_head *bh,
+			     struct ext4_xattr_entry *first, bool block_csum,
+			     struct ext4_xattr_inode_array **ea_inode_array,
+			     int extra_credits, bool skip_quota)
+{
+	struct inode *ea_inode;
+	struct ext4_xattr_entry *entry;
+	bool dirty = false;
+	unsigned int ea_ino;
+	int err;
+	int credits;
+
+	/* One credit for dec ref on ea_inode, one for orphan list addition, */
+	credits = 2 + extra_credits;
+
+	for (entry = first; !IS_LAST_ENTRY(entry);
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino,
+					    le32_to_cpu(entry->e_hash),
+					    &ea_inode);
+		if (err)
+			continue;
+
+		err = ext4_expand_inode_array(ea_inode_array, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode,
+					   "Expand inode array err=%d", err);
+			iput(ea_inode);
+			continue;
+		}
+
+		err = ext4_journal_ensure_credits_fn(handle, credits, credits,
+			ext4_free_metadata_revoke_credits(parent->i_sb, 1),
+			ext4_xattr_restart_fn(handle, parent, bh, block_csum,
+					      dirty));
+		if (err < 0) {
+			ext4_warning_inode(ea_inode, "Ensure credits err=%d",
+					   err);
+			continue;
+		}
+		if (err > 0) {
+			err = ext4_journal_get_write_access(handle, bh);
+			if (err) {
+				ext4_warning_inode(ea_inode,
+						"Re-get write access err=%d",
+						err);
+				continue;
+			}
+		}
+
+		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
+					   err);
+			continue;
+		}
+
+		if (!skip_quota)
+			ext4_xattr_inode_free_quota(parent, ea_inode,
+					      le32_to_cpu(entry->e_value_size));
+
+		/*
+		 * Forget about ea_inode within the same transaction that
+		 * decrements the ref count. This avoids duplicate decrements in
+		 * case the rest of the work spills over to subsequent
+		 * transactions.
+		 */
+		entry->e_value_inum = 0;
+		entry->e_value_size = 0;
+
+		dirty = true;
+	}
+
+	if (dirty) {
+		/*
+		 * Note that we are deliberately skipping csum calculation for
+		 * the final update because we do not expect any journal
+		 * restarts until xattr block is freed.
+		 */
+
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (err)
+			ext4_warning_inode(parent,
+					   "handle dirty metadata err=%d", err);
+	}
+}
+
+/*
+ * Release the xattr block BH: If the reference count is > 1, decrement it;
+ * otherwise free the block.
+ */
+static void
+ext4_xattr_release_block(handle_t *handle, struct inode *inode,
+			 struct buffer_head *bh,
+			 struct ext4_xattr_inode_array **ea_inode_array,
+			 int extra_credits)
+{
+	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
+	u32 hash, ref;
+	int error = 0;
+
+	BUFFER_TRACE(bh, "get_write_access");
+	error = ext4_journal_get_write_access(handle, bh);
+	if (error)
+		goto out;
+
+retry_ref:
+	lock_buffer(bh);
+	hash = le32_to_cpu(BHDR(bh)->h_hash);
+	ref = le32_to_cpu(BHDR(bh)->h_refcount);
+	if (ref == 1) {
+		ea_bdebug(bh, "refcount now=0; freeing");
+		/*
+		 * This must happen under buffer lock for
+		 * ext4_xattr_block_set() to reliably detect freed block
+		 */
+		if (ea_block_cache) {
+			struct mb_cache_entry *oe;
+
+			oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
+							  bh->b_blocknr);
+			if (oe) {
+				unlock_buffer(bh);
+				mb_cache_entry_wait_unused(oe);
+				mb_cache_entry_put(ea_block_cache, oe);
+				goto retry_ref;
+			}
+		}
+		get_bh(bh);
+		unlock_buffer(bh);
+
+		if (ext4_has_feature_ea_inode(inode->i_sb))
+			ext4_xattr_inode_dec_ref_all(handle, inode, bh,
+						     BFIRST(bh),
+						     true /* block_csum */,
+						     ea_inode_array,
+						     extra_credits,
+						     true /* skip_quota */);
+		ext4_free_blocks(handle, inode, bh, 0, 1,
+				 EXT4_FREE_BLOCKS_METADATA |
+				 EXT4_FREE_BLOCKS_FORGET);
+	} else {
+		ref--;
+		BHDR(bh)->h_refcount = cpu_to_le32(ref);
+		if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
+			struct mb_cache_entry *ce;
+
+			if (ea_block_cache) {
+				ce = mb_cache_entry_get(ea_block_cache, hash,
+							bh->b_blocknr);
+				if (ce) {
+					set_bit(MBE_REUSABLE_B, &ce->e_flags);
+					mb_cache_entry_put(ea_block_cache, ce);
+				}
+			}
+		}
+
+		ext4_xattr_block_csum_set(inode, bh);
+		/*
+		 * Beware of this ugliness: Releasing of xattr block references
+		 * from different inodes can race and so we have to protect
+		 * from a race where someone else frees the block (and releases
+		 * its journal_head) before we are done dirtying the buffer. In
+		 * nojournal mode this race is harmless and we actually cannot
+		 * call ext4_handle_dirty_metadata() with locked buffer as
+		 * that function can call sync_dirty_buffer() so for that case
+		 * we handle the dirtying after unlocking the buffer.
+		 */
+		if (ext4_handle_valid(handle))
+			error = ext4_handle_dirty_metadata(handle, inode, bh);
+		unlock_buffer(bh);
+		if (!ext4_handle_valid(handle))
+			error = ext4_handle_dirty_metadata(handle, inode, bh);
+		if (IS_SYNC(inode))
+			ext4_handle_sync(handle);
+		dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
+		ea_bdebug(bh, "refcount now=%d; releasing",
+			  le32_to_cpu(BHDR(bh)->h_refcount));
+	}
+out:
+	ext4_std_error(inode->i_sb, error);
+	return;
+}
+
+/*
+ * Find the available free space for EAs. This also returns the total number of
+ * bytes used by EA entries.
+ */
+static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
+				    size_t *min_offs, void *base, int *total)
+{
+	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+		if (!last->e_value_inum && last->e_value_size) {
+			size_t offs = le16_to_cpu(last->e_value_offs);
+			if (offs < *min_offs)
+				*min_offs = offs;
+		}
+		if (total)
+			*total += EXT4_XATTR_LEN(last->e_name_len);
+	}
+	return (*min_offs - ((void *)last - base) - sizeof(__u32));
+}
+
+/*
+ * Write the value of the EA in an inode.
+ */
+static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
+				  const void *buf, int bufsize)
+{
+	struct buffer_head *bh = NULL;
+	unsigned long block = 0;
+	int blocksize = ea_inode->i_sb->s_blocksize;
+	int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
+	int csize, wsize = 0;
+	int ret = 0, ret2 = 0;
+	int retries = 0;
+
+retry:
+	while (ret >= 0 && ret < max_blocks) {
+		struct ext4_map_blocks map;
+		map.m_lblk = block += ret;
+		map.m_len = max_blocks -= ret;
+
+		ret = ext4_map_blocks(handle, ea_inode, &map,
+				      EXT4_GET_BLOCKS_CREATE);
+		if (ret <= 0) {
+			ext4_mark_inode_dirty(handle, ea_inode);
+			if (ret == -ENOSPC &&
+			    ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
+				ret = 0;
+				goto retry;
+			}
+			break;
+		}
+	}
+
+	if (ret < 0)
+		return ret;
+
+	block = 0;
+	while (wsize < bufsize) {
+		brelse(bh);
+		csize = (bufsize - wsize) > blocksize ? blocksize :
+								bufsize - wsize;
+		bh = ext4_getblk(handle, ea_inode, block, 0);
+		if (IS_ERR(bh))
+			return PTR_ERR(bh);
+		if (!bh) {
+			WARN_ON_ONCE(1);
+			EXT4_ERROR_INODE(ea_inode,
+					 "ext4_getblk() return bh = NULL");
+			return -EFSCORRUPTED;
+		}
+		ret = ext4_journal_get_write_access(handle, bh);
+		if (ret)
+			goto out;
+
+		memcpy(bh->b_data, buf, csize);
+		set_buffer_uptodate(bh);
+		ext4_handle_dirty_metadata(handle, ea_inode, bh);
+
+		buf += csize;
+		wsize += csize;
+		block += 1;
+	}
+
+	inode_lock(ea_inode);
+	i_size_write(ea_inode, wsize);
+	ext4_update_i_disksize(ea_inode, wsize);
+	inode_unlock(ea_inode);
+
+	ret2 = ext4_mark_inode_dirty(handle, ea_inode);
+	if (unlikely(ret2 && !ret))
+		ret = ret2;
+
+out:
+	brelse(bh);
+
+	return ret;
+}
+
+/*
+ * Create an inode to store the value of a large EA.
+ */
+static struct inode *ext4_xattr_inode_create(handle_t *handle,
+					     struct inode *inode, u32 hash)
+{
+	struct inode *ea_inode = NULL;
+	uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
+	int err;
+
+	if (inode->i_sb->s_root == NULL) {
+		ext4_warning(inode->i_sb,
+			     "refuse to create EA inode when umounting");
+		WARN_ON(1);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/*
+	 * Let the next inode be the goal, so we try and allocate the EA inode
+	 * in the same group, or nearby one.
+	 */
+	ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
+				  S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
+				  EXT4_EA_INODE_FL);
+	if (!IS_ERR(ea_inode)) {
+		ea_inode->i_op = &ext4_file_inode_operations;
+		ea_inode->i_fop = &ext4_file_operations;
+		ext4_set_aops(ea_inode);
+		ext4_xattr_inode_set_class(ea_inode);
+		unlock_new_inode(ea_inode);
+		ext4_xattr_inode_set_ref(ea_inode, 1);
+		ext4_xattr_inode_set_hash(ea_inode, hash);
+		err = ext4_mark_inode_dirty(handle, ea_inode);
+		if (!err)
+			err = ext4_inode_attach_jinode(ea_inode);
+		if (err) {
+			if (ext4_xattr_inode_dec_ref(handle, ea_inode))
+				ext4_warning_inode(ea_inode,
+					"cleanup dec ref error %d", err);
+			iput(ea_inode);
+			return ERR_PTR(err);
+		}
+
+		/*
+		 * Xattr inodes are shared therefore quota charging is performed
+		 * at a higher level.
+		 */
+		dquot_free_inode(ea_inode);
+		dquot_drop(ea_inode);
+		inode_lock(ea_inode);
+		ea_inode->i_flags |= S_NOQUOTA;
+		inode_unlock(ea_inode);
+	}
+
+	return ea_inode;
+}
+
+static struct inode *
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+			    size_t value_len, u32 hash)
+{
+	struct inode *ea_inode;
+	struct mb_cache_entry *ce;
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+	void *ea_data;
+
+	if (!ea_inode_cache)
+		return NULL;
+
+	ce = mb_cache_entry_find_first(ea_inode_cache, hash);
+	if (!ce)
+		return NULL;
+
+	WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
+		     !(current->flags & PF_MEMALLOC_NOFS));
+
+	ea_data = kvmalloc(value_len, GFP_KERNEL);
+	if (!ea_data) {
+		mb_cache_entry_put(ea_inode_cache, ce);
+		return NULL;
+	}
+
+	while (ce) {
+		ea_inode = ext4_iget(inode->i_sb, ce->e_value,
+				     EXT4_IGET_EA_INODE);
+		if (IS_ERR(ea_inode))
+			goto next_entry;
+		ext4_xattr_inode_set_class(ea_inode);
+		if (i_size_read(ea_inode) == value_len &&
+		    !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
+		    !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
+						    value_len) &&
+		    !memcmp(value, ea_data, value_len)) {
+			mb_cache_entry_touch(ea_inode_cache, ce);
+			mb_cache_entry_put(ea_inode_cache, ce);
+			kvfree(ea_data);
+			return ea_inode;
+		}
+		iput(ea_inode);
+	next_entry:
+		ce = mb_cache_entry_find_next(ea_inode_cache, ce);
+	}
+	kvfree(ea_data);
+	return NULL;
+}
+
+/*
+ * Add value of the EA in an inode.
+ */
+static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
+					  const void *value, size_t value_len,
+					  struct inode **ret_inode)
+{
+	struct inode *ea_inode;
+	u32 hash;
+	int err;
+
+	hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
+	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
+	if (ea_inode) {
+		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+		if (err) {
+			iput(ea_inode);
+			return err;
+		}
+
+		*ret_inode = ea_inode;
+		return 0;
+	}
+
+	/* Create an inode for the EA value */
+	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
+	if (IS_ERR(ea_inode))
+		return PTR_ERR(ea_inode);
+
+	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
+	if (err) {
+		ext4_xattr_inode_dec_ref(handle, ea_inode);
+		iput(ea_inode);
+		return err;
+	}
+
+	if (EA_INODE_CACHE(inode))
+		mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
+				      ea_inode->i_ino, true /* reusable */);
+
+	*ret_inode = ea_inode;
+	return 0;
+}
+
+/*
+ * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
+ * feature is enabled.
+ */
+#define EXT4_XATTR_BLOCK_RESERVE(inode)	min(i_blocksize(inode)/8, 1024U)
+
+static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
+				struct ext4_xattr_search *s,
+				handle_t *handle, struct inode *inode,
+				bool is_block)
+{
+	struct ext4_xattr_entry *last, *next;
+	struct ext4_xattr_entry *here = s->here;
+	size_t min_offs = s->end - s->base, name_len = strlen(i->name);
+	int in_inode = i->in_inode;
+	struct inode *old_ea_inode = NULL;
+	struct inode *new_ea_inode = NULL;
+	size_t old_size, new_size;
+	int ret;
+
+	/* Space used by old and new values. */
+	old_size = (!s->not_found && !here->e_value_inum) ?
+			EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
+	new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
+
+	/*
+	 * Optimization for the simple case when old and new values have the
+	 * same padded sizes. Not applicable if external inodes are involved.
+	 */
+	if (new_size && new_size == old_size) {
+		size_t offs = le16_to_cpu(here->e_value_offs);
+		void *val = s->base + offs;
+
+		here->e_value_size = cpu_to_le32(i->value_len);
+		if (i->value == EXT4_ZERO_XATTR_VALUE) {
+			memset(val, 0, new_size);
+		} else {
+			memcpy(val, i->value, i->value_len);
+			/* Clear padding bytes. */
+			memset(val + i->value_len, 0, new_size - i->value_len);
+		}
+		goto update_hash;
+	}
+
+	/* Compute min_offs and last. */
+	last = s->first;
+	for (; !IS_LAST_ENTRY(last); last = next) {
+		next = EXT4_XATTR_NEXT(last);
+		if ((void *)next >= s->end) {
+			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
+			ret = -EFSCORRUPTED;
+			goto out;
+		}
+		if (!last->e_value_inum && last->e_value_size) {
+			size_t offs = le16_to_cpu(last->e_value_offs);
+			if (offs < min_offs)
+				min_offs = offs;
+		}
+	}
+
+	/* Check whether we have enough space. */
+	if (i->value) {
+		size_t free;
+
+		free = min_offs - ((void *)last - s->base) - sizeof(__u32);
+		if (!s->not_found)
+			free += EXT4_XATTR_LEN(name_len) + old_size;
+
+		if (free < EXT4_XATTR_LEN(name_len) + new_size) {
+			ret = -ENOSPC;
+			goto out;
+		}
+
+		/*
+		 * If storing the value in an external inode is an option,
+		 * reserve space for xattr entries/names in the external
+		 * attribute block so that a long value does not occupy the
+		 * whole space and prevent further entries being added.
+		 */
+		if (ext4_has_feature_ea_inode(inode->i_sb) &&
+		    new_size && is_block &&
+		    (min_offs + old_size - new_size) <
+					EXT4_XATTR_BLOCK_RESERVE(inode)) {
+			ret = -ENOSPC;
+			goto out;
+		}
+	}
+
+	/*
+	 * Getting access to old and new ea inodes is subject to failures.
+	 * Finish that work before doing any modifications to the xattr data.
+	 */
+	if (!s->not_found && here->e_value_inum) {
+		ret = ext4_xattr_inode_iget(inode,
+					    le32_to_cpu(here->e_value_inum),
+					    le32_to_cpu(here->e_hash),
+					    &old_ea_inode);
+		if (ret) {
+			old_ea_inode = NULL;
+			goto out;
+		}
+	}
+	if (i->value && in_inode) {
+		WARN_ON_ONCE(!i->value_len);
+
+		ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
+		if (ret)
+			goto out;
+
+		ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
+						     i->value_len,
+						     &new_ea_inode);
+		if (ret) {
+			new_ea_inode = NULL;
+			ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
+			goto out;
+		}
+	}
+
+	if (old_ea_inode) {
+		/* We are ready to release ref count on the old_ea_inode. */
+		ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
+		if (ret) {
+			/* Release newly required ref count on new_ea_inode. */
+			if (new_ea_inode) {
+				int err;
+
+				err = ext4_xattr_inode_dec_ref(handle,
+							       new_ea_inode);
+				if (err)
+					ext4_warning_inode(new_ea_inode,
+						  "dec ref new_ea_inode err=%d",
+						  err);
+				ext4_xattr_inode_free_quota(inode, new_ea_inode,
+							    i->value_len);
+			}
+			goto out;
+		}
+
+		ext4_xattr_inode_free_quota(inode, old_ea_inode,
+					    le32_to_cpu(here->e_value_size));
+	}
+
+	/* No failures allowed past this point. */
+
+	if (!s->not_found && here->e_value_size && !here->e_value_inum) {
+		/* Remove the old value. */
+		void *first_val = s->base + min_offs;
+		size_t offs = le16_to_cpu(here->e_value_offs);
+		void *val = s->base + offs;
+
+		memmove(first_val + old_size, first_val, val - first_val);
+		memset(first_val, 0, old_size);
+		min_offs += old_size;
+
+		/* Adjust all value offsets. */
+		last = s->first;
+		while (!IS_LAST_ENTRY(last)) {
+			size_t o = le16_to_cpu(last->e_value_offs);
+
+			if (!last->e_value_inum &&
+			    last->e_value_size && o < offs)
+				last->e_value_offs = cpu_to_le16(o + old_size);
+			last = EXT4_XATTR_NEXT(last);
+		}
+	}
+
+	if (!i->value) {
+		/* Remove old name. */
+		size_t size = EXT4_XATTR_LEN(name_len);
+
+		last = ENTRY((void *)last - size);
+		memmove(here, (void *)here + size,
+			(void *)last - (void *)here + sizeof(__u32));
+		memset(last, 0, size);
+
+		/*
+		 * Update i_inline_off - moved ibody region might contain
+		 * system.data attribute.  Handling a failure here won't
+		 * cause other complications for setting an xattr.
+		 */
+		if (!is_block && ext4_has_inline_data(inode)) {
+			ret = ext4_find_inline_data_nolock(inode);
+			if (ret) {
+				ext4_warning_inode(inode,
+					"unable to update i_inline_off");
+				goto out;
+			}
+		}
+	} else if (s->not_found) {
+		/* Insert new name. */
+		size_t size = EXT4_XATTR_LEN(name_len);
+		size_t rest = (void *)last - (void *)here + sizeof(__u32);
+
+		memmove((void *)here + size, here, rest);
+		memset(here, 0, size);
+		here->e_name_index = i->name_index;
+		here->e_name_len = name_len;
+		memcpy(here->e_name, i->name, name_len);
+	} else {
+		/* This is an update, reset value info. */
+		here->e_value_inum = 0;
+		here->e_value_offs = 0;
+		here->e_value_size = 0;
+	}
+
+	if (i->value) {
+		/* Insert new value. */
+		if (in_inode) {
+			here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
+		} else if (i->value_len) {
+			void *val = s->base + min_offs - new_size;
+
+			here->e_value_offs = cpu_to_le16(min_offs - new_size);
+			if (i->value == EXT4_ZERO_XATTR_VALUE) {
+				memset(val, 0, new_size);
+			} else {
+				memcpy(val, i->value, i->value_len);
+				/* Clear padding bytes. */
+				memset(val + i->value_len, 0,
+				       new_size - i->value_len);
+			}
+		}
+		here->e_value_size = cpu_to_le32(i->value_len);
+	}
+
+update_hash:
+	if (i->value) {
+		__le32 hash = 0;
+
+		/* Entry hash calculation. */
+		if (in_inode) {
+			__le32 crc32c_hash;
+
+			/*
+			 * Feed crc32c hash instead of the raw value for entry
+			 * hash calculation. This is to avoid walking
+			 * potentially long value buffer again.
+			 */
+			crc32c_hash = cpu_to_le32(
+				       ext4_xattr_inode_get_hash(new_ea_inode));
+			hash = ext4_xattr_hash_entry(here->e_name,
+						     here->e_name_len,
+						     &crc32c_hash, 1);
+		} else if (is_block) {
+			__le32 *value = s->base + le16_to_cpu(
+							here->e_value_offs);
+
+			hash = ext4_xattr_hash_entry(here->e_name,
+						     here->e_name_len, value,
+						     new_size >> 2);
+		}
+		here->e_hash = hash;
+	}
+
+	if (is_block)
+		ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
+
+	ret = 0;
+out:
+	iput(old_ea_inode);
+	iput(new_ea_inode);
+	return ret;
+}
+
+struct ext4_xattr_block_find {
+	struct ext4_xattr_search s;
+	struct buffer_head *bh;
+};
+
+static int
+ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
+		      struct ext4_xattr_block_find *bs)
+{
+	struct super_block *sb = inode->i_sb;
+	int error;
+
+	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
+		  i->name_index, i->name, i->value, (long)i->value_len);
+
+	if (EXT4_I(inode)->i_file_acl) {
+		/* The inode already has an extended attribute block. */
+		bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+		if (IS_ERR(bs->bh)) {
+			error = PTR_ERR(bs->bh);
+			bs->bh = NULL;
+			return error;
+		}
+		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
+			atomic_read(&(bs->bh->b_count)),
+			le32_to_cpu(BHDR(bs->bh)->h_refcount));
+		error = ext4_xattr_check_block(inode, bs->bh);
+		if (error)
+			return error;
+		/* Find the named attribute. */
+		bs->s.base = BHDR(bs->bh);
+		bs->s.first = BFIRST(bs->bh);
+		bs->s.end = bs->bh->b_data + bs->bh->b_size;
+		bs->s.here = bs->s.first;
+		error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
+					 i->name_index, i->name, 1);
+		if (error && error != -ENODATA)
+			return error;
+		bs->s.not_found = error;
+	}
+	return 0;
+}
+
+static int
+ext4_xattr_block_set(handle_t *handle, struct inode *inode,
+		     struct ext4_xattr_info *i,
+		     struct ext4_xattr_block_find *bs)
+{
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *new_bh = NULL;
+	struct ext4_xattr_search s_copy = bs->s;
+	struct ext4_xattr_search *s = &s_copy;
+	struct mb_cache_entry *ce = NULL;
+	int error = 0;
+	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
+	struct inode *ea_inode = NULL, *tmp_inode;
+	size_t old_ea_inode_quota = 0;
+	unsigned int ea_ino;
+
+
+#define header(x) ((struct ext4_xattr_header *)(x))
+
+	if (s->base) {
+		int offset = (char *)s->here - bs->bh->b_data;
+
+		BUFFER_TRACE(bs->bh, "get_write_access");
+		error = ext4_journal_get_write_access(handle, bs->bh);
+		if (error)
+			goto cleanup;
+		lock_buffer(bs->bh);
+
+		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
+			__u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
+
+			/*
+			 * This must happen under buffer lock for
+			 * ext4_xattr_block_set() to reliably detect modified
+			 * block
+			 */
+			if (ea_block_cache) {
+				struct mb_cache_entry *oe;
+
+				oe = mb_cache_entry_delete_or_get(ea_block_cache,
+					hash, bs->bh->b_blocknr);
+				if (oe) {
+					/*
+					 * Xattr block is getting reused. Leave
+					 * it alone.
+					 */
+					mb_cache_entry_put(ea_block_cache, oe);
+					goto clone_block;
+				}
+			}
+			ea_bdebug(bs->bh, "modifying in-place");
+			error = ext4_xattr_set_entry(i, s, handle, inode,
+						     true /* is_block */);
+			ext4_xattr_block_csum_set(inode, bs->bh);
+			unlock_buffer(bs->bh);
+			if (error == -EFSCORRUPTED)
+				goto bad_block;
+			if (!error)
+				error = ext4_handle_dirty_metadata(handle,
+								   inode,
+								   bs->bh);
+			if (error)
+				goto cleanup;
+			goto inserted;
+		}
+clone_block:
+		unlock_buffer(bs->bh);
+		ea_bdebug(bs->bh, "cloning");
+		s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
+		error = -ENOMEM;
+		if (s->base == NULL)
+			goto cleanup;
+		s->first = ENTRY(header(s->base)+1);
+		header(s->base)->h_refcount = cpu_to_le32(1);
+		s->here = ENTRY(s->base + offset);
+		s->end = s->base + bs->bh->b_size;
+
+		/*
+		 * If existing entry points to an xattr inode, we need
+		 * to prevent ext4_xattr_set_entry() from decrementing
+		 * ref count on it because the reference belongs to the
+		 * original block. In this case, make the entry look
+		 * like it has an empty value.
+		 */
+		if (!s->not_found && s->here->e_value_inum) {
+			ea_ino = le32_to_cpu(s->here->e_value_inum);
+			error = ext4_xattr_inode_iget(inode, ea_ino,
+				      le32_to_cpu(s->here->e_hash),
+				      &tmp_inode);
+			if (error)
+				goto cleanup;
+
+			if (!ext4_test_inode_state(tmp_inode,
+					EXT4_STATE_LUSTRE_EA_INODE)) {
+				/*
+				 * Defer quota free call for previous
+				 * inode until success is guaranteed.
+				 */
+				old_ea_inode_quota = le32_to_cpu(
+						s->here->e_value_size);
+			}
+			iput(tmp_inode);
+
+			s->here->e_value_inum = 0;
+			s->here->e_value_size = 0;
+		}
+	} else {
+		/* Allocate a buffer where we construct the new block. */
+		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
+		/* assert(header == s->base) */
+		error = -ENOMEM;
+		if (s->base == NULL)
+			goto cleanup;
+		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
+		header(s->base)->h_blocks = cpu_to_le32(1);
+		header(s->base)->h_refcount = cpu_to_le32(1);
+		s->first = ENTRY(header(s->base)+1);
+		s->here = ENTRY(header(s->base)+1);
+		s->end = s->base + sb->s_blocksize;
+	}
+
+	error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
+	if (error == -EFSCORRUPTED)
+		goto bad_block;
+	if (error)
+		goto cleanup;
+
+	if (i->value && s->here->e_value_inum) {
+		/*
+		 * A ref count on ea_inode has been taken as part of the call to
+		 * ext4_xattr_set_entry() above. We would like to drop this
+		 * extra ref but we have to wait until the xattr block is
+		 * initialized and has its own ref count on the ea_inode.
+		 */
+		ea_ino = le32_to_cpu(s->here->e_value_inum);
+		error = ext4_xattr_inode_iget(inode, ea_ino,
+					      le32_to_cpu(s->here->e_hash),
+					      &ea_inode);
+		if (error) {
+			ea_inode = NULL;
+			goto cleanup;
+		}
+	}
+
+inserted:
+	if (!IS_LAST_ENTRY(s->first)) {
+		new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
+						     &ce);
+		if (new_bh) {
+			/* We found an identical block in the cache. */
+			if (new_bh == bs->bh)
+				ea_bdebug(new_bh, "keeping");
+			else {
+				u32 ref;
+
+#ifdef EXT4_XATTR_DEBUG
+				WARN_ON_ONCE(dquot_initialize_needed(inode));
+#endif
+				/* The old block is released after updating
+				   the inode. */
+				error = dquot_alloc_block(inode,
+						EXT4_C2B(EXT4_SB(sb), 1));
+				if (error)
+					goto cleanup;
+				BUFFER_TRACE(new_bh, "get_write_access");
+				error = ext4_journal_get_write_access(handle,
+								      new_bh);
+				if (error)
+					goto cleanup_dquot;
+				lock_buffer(new_bh);
+				/*
+				 * We have to be careful about races with
+				 * adding references to xattr block. Once we
+				 * hold buffer lock xattr block's state is
+				 * stable so we can check the additional
+				 * reference fits.
+				 */
+				ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
+				if (ref > EXT4_XATTR_REFCOUNT_MAX) {
+					/*
+					 * Undo everything and check mbcache
+					 * again.
+					 */
+					unlock_buffer(new_bh);
+					dquot_free_block(inode,
+							 EXT4_C2B(EXT4_SB(sb),
+								  1));
+					brelse(new_bh);
+					mb_cache_entry_put(ea_block_cache, ce);
+					ce = NULL;
+					new_bh = NULL;
+					goto inserted;
+				}
+				BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
+				if (ref == EXT4_XATTR_REFCOUNT_MAX)
+					clear_bit(MBE_REUSABLE_B, &ce->e_flags);
+				ea_bdebug(new_bh, "reusing; refcount now=%d",
+					  ref);
+				ext4_xattr_block_csum_set(inode, new_bh);
+				unlock_buffer(new_bh);
+				error = ext4_handle_dirty_metadata(handle,
+								   inode,
+								   new_bh);
+				if (error)
+					goto cleanup_dquot;
+			}
+			mb_cache_entry_touch(ea_block_cache, ce);
+			mb_cache_entry_put(ea_block_cache, ce);
+			ce = NULL;
+		} else if (bs->bh && s->base == bs->bh->b_data) {
+			/* We were modifying this block in-place. */
+			ea_bdebug(bs->bh, "keeping this block");
+			ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
+			new_bh = bs->bh;
+			get_bh(new_bh);
+		} else {
+			/* We need to allocate a new block */
+			ext4_fsblk_t goal, block;
+
+#ifdef EXT4_XATTR_DEBUG
+			WARN_ON_ONCE(dquot_initialize_needed(inode));
+#endif
+			goal = ext4_group_first_block_no(sb,
+						EXT4_I(inode)->i_block_group);
+			block = ext4_new_meta_blocks(handle, inode, goal, 0,
+						     NULL, &error);
+			if (error)
+				goto cleanup;
+
+			ea_idebug(inode, "creating block %llu",
+				  (unsigned long long)block);
+
+			new_bh = sb_getblk(sb, block);
+			if (unlikely(!new_bh)) {
+				error = -ENOMEM;
+getblk_failed:
+				ext4_free_blocks(handle, inode, NULL, block, 1,
+						 EXT4_FREE_BLOCKS_METADATA);
+				goto cleanup;
+			}
+			error = ext4_xattr_inode_inc_ref_all(handle, inode,
+						      ENTRY(header(s->base)+1));
+			if (error)
+				goto getblk_failed;
+			if (ea_inode) {
+				/* Drop the extra ref on ea_inode. */
+				error = ext4_xattr_inode_dec_ref(handle,
+								 ea_inode);
+				if (error)
+					ext4_warning_inode(ea_inode,
+							   "dec ref error=%d",
+							   error);
+				iput(ea_inode);
+				ea_inode = NULL;
+			}
+
+			lock_buffer(new_bh);
+			error = ext4_journal_get_create_access(handle, new_bh);
+			if (error) {
+				unlock_buffer(new_bh);
+				error = -EIO;
+				goto getblk_failed;
+			}
+			memcpy(new_bh->b_data, s->base, new_bh->b_size);
+			ext4_xattr_block_csum_set(inode, new_bh);
+			set_buffer_uptodate(new_bh);
+			unlock_buffer(new_bh);
+			ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
+			error = ext4_handle_dirty_metadata(handle, inode,
+							   new_bh);
+			if (error)
+				goto cleanup;
+		}
+	}
+
+	if (old_ea_inode_quota)
+		ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
+
+	/* Update the inode. */
+	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
+
+	/* Drop the previous xattr block. */
+	if (bs->bh && bs->bh != new_bh) {
+		struct ext4_xattr_inode_array *ea_inode_array = NULL;
+
+		ext4_xattr_release_block(handle, inode, bs->bh,
+					 &ea_inode_array,
+					 0 /* extra_credits */);
+		ext4_xattr_inode_array_free(ea_inode_array);
+	}
+	error = 0;
+
+cleanup:
+	if (ea_inode) {
+		int error2;
+
+		error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (error2)
+			ext4_warning_inode(ea_inode, "dec ref error=%d",
+					   error2);
+
+		/* If there was an error, revert the quota charge. */
+		if (error)
+			ext4_xattr_inode_free_quota(inode, ea_inode,
+						    i_size_read(ea_inode));
+		iput(ea_inode);
+	}
+	if (ce)
+		mb_cache_entry_put(ea_block_cache, ce);
+	brelse(new_bh);
+	if (!(bs->bh && s->base == bs->bh->b_data))
+		kfree(s->base);
+
+	return error;
+
+cleanup_dquot:
+	dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
+	goto cleanup;
+
+bad_block:
+	EXT4_ERROR_INODE(inode, "bad block %llu",
+			 EXT4_I(inode)->i_file_acl);
+	goto cleanup;
+
+#undef header
+}
+
+int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
+			  struct ext4_xattr_ibody_find *is)
+{
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_inode *raw_inode;
+	int error;
+
+	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
+		return 0;
+
+	raw_inode = ext4_raw_inode(&is->iloc);
+	header = IHDR(inode, raw_inode);
+	is->s.base = is->s.first = IFIRST(header);
+	is->s.here = is->s.first;
+	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
+		error = xattr_check_inode(inode, header, is->s.end);
+		if (error)
+			return error;
+		/* Find the named attribute. */
+		error = xattr_find_entry(inode, &is->s.here, is->s.end,
+					 i->name_index, i->name, 0);
+		if (error && error != -ENODATA)
+			return error;
+		is->s.not_found = error;
+	}
+	return 0;
+}
+
+int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
+				struct ext4_xattr_info *i,
+				struct ext4_xattr_ibody_find *is)
+{
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_xattr_search *s = &is->s;
+	int error;
+
+	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
+		return -ENOSPC;
+
+	error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
+	if (error)
+		return error;
+	header = IHDR(inode, ext4_raw_inode(&is->iloc));
+	if (!IS_LAST_ENTRY(s->first)) {
+		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
+		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
+	} else {
+		header->h_magic = cpu_to_le32(0);
+		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
+	}
+	return 0;
+}
+
+static int ext4_xattr_value_same(struct ext4_xattr_search *s,
+				 struct ext4_xattr_info *i)
+{
+	void *value;
+
+	/* When e_value_inum is set the value is stored externally. */
+	if (s->here->e_value_inum)
+		return 0;
+	if (le32_to_cpu(s->here->e_value_size) != i->value_len)
+		return 0;
+	value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
+	return !memcmp(value, i->value, i->value_len);
+}
+
+static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
+{
+	struct buffer_head *bh;
+	int error;
+
+	if (!EXT4_I(inode)->i_file_acl)
+		return NULL;
+	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+	if (IS_ERR(bh))
+		return bh;
+	error = ext4_xattr_check_block(inode, bh);
+	if (error) {
+		brelse(bh);
+		return ERR_PTR(error);
+	}
+	return bh;
+}
+
+/*
+ * ext4_xattr_set_handle()
+ *
+ * Create, replace or remove an extended attribute for this inode.  Value
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
+		      const char *name, const void *value, size_t value_len,
+		      int flags)
+{
+	struct ext4_xattr_info i = {
+		.name_index = name_index,
+		.name = name,
+		.value = value,
+		.value_len = value_len,
+		.in_inode = 0,
+	};
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext4_xattr_block_find bs = {
+		.s = { .not_found = -ENODATA, },
+	};
+	int no_expand;
+	int error;
+
+	if (!name)
+		return -EINVAL;
+	if (strlen(name) > 255)
+		return -ERANGE;
+
+	ext4_write_lock_xattr(inode, &no_expand);
+
+	/* Check journal credits under write lock. */
+	if (ext4_handle_valid(handle)) {
+		struct buffer_head *bh;
+		int credits;
+
+		bh = ext4_xattr_get_block(inode);
+		if (IS_ERR(bh)) {
+			error = PTR_ERR(bh);
+			goto cleanup;
+		}
+
+		credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
+						   value_len,
+						   flags & XATTR_CREATE);
+		brelse(bh);
+
+		if (jbd2_handle_buffer_credits(handle) < credits) {
+			error = -ENOSPC;
+			goto cleanup;
+		}
+		WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
+	}
+
+	error = ext4_reserve_inode_write(handle, inode, &is.iloc);
+	if (error)
+		goto cleanup;
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
+		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
+		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
+		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
+	}
+
+	error = ext4_xattr_ibody_find(inode, &i, &is);
+	if (error)
+		goto cleanup;
+	if (is.s.not_found)
+		error = ext4_xattr_block_find(inode, &i, &bs);
+	if (error)
+		goto cleanup;
+	if (is.s.not_found && bs.s.not_found) {
+		error = -ENODATA;
+		if (flags & XATTR_REPLACE)
+			goto cleanup;
+		error = 0;
+		if (!value)
+			goto cleanup;
+	} else {
+		error = -EEXIST;
+		if (flags & XATTR_CREATE)
+			goto cleanup;
+	}
+
+	if (!value) {
+		if (!is.s.not_found)
+			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
+		else if (!bs.s.not_found)
+			error = ext4_xattr_block_set(handle, inode, &i, &bs);
+	} else {
+		error = 0;
+		/* Xattr value did not change? Save us some work and bail out */
+		if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
+			goto cleanup;
+		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
+			goto cleanup;
+
+		if (ext4_has_feature_ea_inode(inode->i_sb) &&
+		    (EXT4_XATTR_SIZE(i.value_len) >
+			EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
+			i.in_inode = 1;
+retry_inode:
+		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
+		if (!error && !bs.s.not_found) {
+			i.value = NULL;
+			error = ext4_xattr_block_set(handle, inode, &i, &bs);
+		} else if (error == -ENOSPC) {
+			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
+				brelse(bs.bh);
+				bs.bh = NULL;
+				error = ext4_xattr_block_find(inode, &i, &bs);
+				if (error)
+					goto cleanup;
+			}
+			error = ext4_xattr_block_set(handle, inode, &i, &bs);
+			if (!error && !is.s.not_found) {
+				i.value = NULL;
+				error = ext4_xattr_ibody_set(handle, inode, &i,
+							     &is);
+			} else if (error == -ENOSPC) {
+				/*
+				 * Xattr does not fit in the block, store at
+				 * external inode if possible.
+				 */
+				if (ext4_has_feature_ea_inode(inode->i_sb) &&
+				    i.value_len && !i.in_inode) {
+					i.in_inode = 1;
+					goto retry_inode;
+				}
+			}
+		}
+	}
+	if (!error) {
+		ext4_xattr_update_super_block(handle, inode->i_sb);
+		inode->i_ctime = current_time(inode);
+		if (!value)
+			no_expand = 0;
+		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
+		/*
+		 * The bh is consumed by ext4_mark_iloc_dirty, even with
+		 * error != 0.
+		 */
+		is.iloc.bh = NULL;
+		if (IS_SYNC(inode))
+			ext4_handle_sync(handle);
+	}
+	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
+
+cleanup:
+	brelse(is.iloc.bh);
+	brelse(bs.bh);
+	ext4_write_unlock_xattr(inode, &no_expand);
+	return error;
+}
+
+int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+			   bool is_create, int *credits)
+{
+	struct buffer_head *bh;
+	int err;
+
+	*credits = 0;
+
+	if (!EXT4_SB(inode->i_sb)->s_journal)
+		return 0;
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+
+	bh = ext4_xattr_get_block(inode);
+	if (IS_ERR(bh)) {
+		err = PTR_ERR(bh);
+	} else {
+		*credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
+						    value_len, is_create);
+		brelse(bh);
+		err = 0;
+	}
+
+	up_read(&EXT4_I(inode)->xattr_sem);
+	return err;
+}
+
+/*
+ * ext4_xattr_set()
+ *
+ * Like ext4_xattr_set_handle, but start from an inode. This extended
+ * attribute modification is a filesystem transaction by itself.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext4_xattr_set(struct inode *inode, int name_index, const char *name,
+	       const void *value, size_t value_len, int flags)
+{
+	handle_t *handle;
+	struct super_block *sb = inode->i_sb;
+	int error, retries = 0;
+	int credits;
+
+	error = dquot_initialize(inode);
+	if (error)
+		return error;
+
+retry:
+	error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
+				       &credits);
+	if (error)
+		return error;
+
+	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
+	if (IS_ERR(handle)) {
+		error = PTR_ERR(handle);
+	} else {
+		int error2;
+
+		error = ext4_xattr_set_handle(handle, inode, name_index, name,
+					      value, value_len, flags);
+		error2 = ext4_journal_stop(handle);
+		if (error == -ENOSPC &&
+		    ext4_should_retry_alloc(sb, &retries))
+			goto retry;
+		if (error == 0)
+			error = error2;
+	}
+	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
+
+	return error;
+}
+
+/*
+ * Shift the EA entries in the inode to create space for the increased
+ * i_extra_isize.
+ */
+static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
+				     int value_offs_shift, void *to,
+				     void *from, size_t n)
+{
+	struct ext4_xattr_entry *last = entry;
+	int new_offs;
+
+	/* We always shift xattr headers further thus offsets get lower */
+	BUG_ON(value_offs_shift > 0);
+
+	/* Adjust the value offsets of the entries */
+	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+		if (!last->e_value_inum && last->e_value_size) {
+			new_offs = le16_to_cpu(last->e_value_offs) +
+							value_offs_shift;
+			last->e_value_offs = cpu_to_le16(new_offs);
+		}
+	}
+	/* Shift the entries by n bytes */
+	memmove(to, from, n);
+}
+
+/*
+ * Move xattr pointed to by 'entry' from inode into external xattr block
+ */
+static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
+				    struct ext4_inode *raw_inode,
+				    struct ext4_xattr_entry *entry)
+{
+	struct ext4_xattr_ibody_find *is = NULL;
+	struct ext4_xattr_block_find *bs = NULL;
+	char *buffer = NULL, *b_entry_name = NULL;
+	size_t value_size = le32_to_cpu(entry->e_value_size);
+	struct ext4_xattr_info i = {
+		.value = NULL,
+		.value_len = 0,
+		.name_index = entry->e_name_index,
+		.in_inode = !!entry->e_value_inum,
+	};
+	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
+	int needs_kvfree = 0;
+	int error;
+
+	is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
+	bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
+	b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
+	if (!is || !bs || !b_entry_name) {
+		error = -ENOMEM;
+		goto out;
+	}
+
+	is->s.not_found = -ENODATA;
+	bs->s.not_found = -ENODATA;
+	is->iloc.bh = NULL;
+	bs->bh = NULL;
+
+	/* Save the entry name and the entry value */
+	if (entry->e_value_inum) {
+		buffer = kvmalloc(value_size, GFP_NOFS);
+		if (!buffer) {
+			error = -ENOMEM;
+			goto out;
+		}
+		needs_kvfree = 1;
+		error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
+		if (error)
+			goto out;
+	} else {
+		size_t value_offs = le16_to_cpu(entry->e_value_offs);
+		buffer = (void *)IFIRST(header) + value_offs;
+	}
+
+	memcpy(b_entry_name, entry->e_name, entry->e_name_len);
+	b_entry_name[entry->e_name_len] = '\0';
+	i.name = b_entry_name;
+
+	error = ext4_get_inode_loc(inode, &is->iloc);
+	if (error)
+		goto out;
+
+	error = ext4_xattr_ibody_find(inode, &i, is);
+	if (error)
+		goto out;
+
+	i.value = buffer;
+	i.value_len = value_size;
+	error = ext4_xattr_block_find(inode, &i, bs);
+	if (error)
+		goto out;
+
+	/* Move ea entry from the inode into the block */
+	error = ext4_xattr_block_set(handle, inode, &i, bs);
+	if (error)
+		goto out;
+
+	/* Remove the chosen entry from the inode */
+	i.value = NULL;
+	i.value_len = 0;
+	error = ext4_xattr_ibody_set(handle, inode, &i, is);
+
+out:
+	kfree(b_entry_name);
+	if (needs_kvfree && buffer)
+		kvfree(buffer);
+	if (is)
+		brelse(is->iloc.bh);
+	if (bs)
+		brelse(bs->bh);
+	kfree(is);
+	kfree(bs);
+
+	return error;
+}
+
+static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
+				       struct ext4_inode *raw_inode,
+				       int isize_diff, size_t ifree,
+				       size_t bfree, int *total_ino)
+{
+	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
+	struct ext4_xattr_entry *small_entry;
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_entry *last;
+	unsigned int entry_size;	/* EA entry size */
+	unsigned int total_size;	/* EA entry size + value size */
+	unsigned int min_total_size;
+	int error;
+
+	while (isize_diff > ifree) {
+		entry = NULL;
+		small_entry = NULL;
+		min_total_size = ~0U;
+		last = IFIRST(header);
+		/* Find the entry best suited to be pushed into EA block */
+		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+			/* never move system.data out of the inode */
+			if ((last->e_name_len == 4) &&
+			    (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
+			    !memcmp(last->e_name, "data", 4))
+				continue;
+			total_size = EXT4_XATTR_LEN(last->e_name_len);
+			if (!last->e_value_inum)
+				total_size += EXT4_XATTR_SIZE(
+					       le32_to_cpu(last->e_value_size));
+			if (total_size <= bfree &&
+			    total_size < min_total_size) {
+				if (total_size + ifree < isize_diff) {
+					small_entry = last;
+				} else {
+					entry = last;
+					min_total_size = total_size;
+				}
+			}
+		}
+
+		if (entry == NULL) {
+			if (small_entry == NULL)
+				return -ENOSPC;
+			entry = small_entry;
+		}
+
+		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
+		total_size = entry_size;
+		if (!entry->e_value_inum)
+			total_size += EXT4_XATTR_SIZE(
+					      le32_to_cpu(entry->e_value_size));
+		error = ext4_xattr_move_to_block(handle, inode, raw_inode,
+						 entry);
+		if (error)
+			return error;
+
+		*total_ino -= entry_size;
+		ifree += total_size;
+		bfree -= total_size;
+	}
+
+	return 0;
+}
+
+/*
+ * Expand an inode by new_extra_isize bytes when EAs are present.
+ * Returns 0 on success or negative error number on failure.
+ */
+int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
+			       struct ext4_inode *raw_inode, handle_t *handle)
+{
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	static unsigned int mnt_count;
+	size_t min_offs;
+	size_t ifree, bfree;
+	int total_ino;
+	void *base, *end;
+	int error = 0, tried_min_extra_isize = 0;
+	int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
+	int isize_diff;	/* How much do we need to grow i_extra_isize */
+
+retry:
+	isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
+	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
+		return 0;
+
+	header = IHDR(inode, raw_inode);
+
+	/*
+	 * Check if enough free space is available in the inode to shift the
+	 * entries ahead by new_extra_isize.
+	 */
+
+	base = IFIRST(header);
+	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+	min_offs = end - base;
+	total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
+
+	error = xattr_check_inode(inode, header, end);
+	if (error)
+		goto cleanup;
+
+	ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
+	if (ifree >= isize_diff)
+		goto shift;
+
+	/*
+	 * Enough free space isn't available in the inode, check if
+	 * EA block can hold new_extra_isize bytes.
+	 */
+	if (EXT4_I(inode)->i_file_acl) {
+		struct buffer_head *bh;
+
+		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+		if (IS_ERR(bh)) {
+			error = PTR_ERR(bh);
+			goto cleanup;
+		}
+		error = ext4_xattr_check_block(inode, bh);
+		if (error) {
+			brelse(bh);
+			goto cleanup;
+		}
+		base = BHDR(bh);
+		end = bh->b_data + bh->b_size;
+		min_offs = end - base;
+		bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
+					      NULL);
+		brelse(bh);
+		if (bfree + ifree < isize_diff) {
+			if (!tried_min_extra_isize && s_min_extra_isize) {
+				tried_min_extra_isize++;
+				new_extra_isize = s_min_extra_isize;
+				goto retry;
+			}
+			error = -ENOSPC;
+			goto cleanup;
+		}
+	} else {
+		bfree = inode->i_sb->s_blocksize;
+	}
+
+	error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
+					    isize_diff, ifree, bfree,
+					    &total_ino);
+	if (error) {
+		if (error == -ENOSPC && !tried_min_extra_isize &&
+		    s_min_extra_isize) {
+			tried_min_extra_isize++;
+			new_extra_isize = s_min_extra_isize;
+			goto retry;
+		}
+		goto cleanup;
+	}
+shift:
+	/* Adjust the offsets and shift the remaining entries ahead */
+	ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
+			- new_extra_isize, (void *)raw_inode +
+			EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
+			(void *)header, total_ino);
+	EXT4_I(inode)->i_extra_isize = new_extra_isize;
+
+	if (ext4_has_inline_data(inode))
+		error = ext4_find_inline_data_nolock(inode);
+
+cleanup:
+	if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
+		ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
+			     inode->i_ino);
+		mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
+	}
+	return error;
+}
+
+#define EIA_INCR 16 /* must be 2^n */
+#define EIA_MASK (EIA_INCR - 1)
+
+/* Add the large xattr @inode into @ea_inode_array for deferred iput().
+ * If @ea_inode_array is new or full it will be grown and the old
+ * contents copied over.
+ */
+static int
+ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
+			struct inode *inode)
+{
+	if (*ea_inode_array == NULL) {
+		/*
+		 * Start with 15 inodes, so it fits into a power-of-two size.
+		 * If *ea_inode_array is NULL, this is essentially offsetof()
+		 */
+		(*ea_inode_array) =
+			kmalloc(offsetof(struct ext4_xattr_inode_array,
+					 inodes[EIA_MASK]),
+				GFP_NOFS);
+		if (*ea_inode_array == NULL)
+			return -ENOMEM;
+		(*ea_inode_array)->count = 0;
+	} else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
+		/* expand the array once all 15 + n * 16 slots are full */
+		struct ext4_xattr_inode_array *new_array = NULL;
+		int count = (*ea_inode_array)->count;
+
+		/* if new_array is NULL, this is essentially offsetof() */
+		new_array = kmalloc(
+				offsetof(struct ext4_xattr_inode_array,
+					 inodes[count + EIA_INCR]),
+				GFP_NOFS);
+		if (new_array == NULL)
+			return -ENOMEM;
+		memcpy(new_array, *ea_inode_array,
+		       offsetof(struct ext4_xattr_inode_array, inodes[count]));
+		kfree(*ea_inode_array);
+		*ea_inode_array = new_array;
+	}
+	(*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
+	return 0;
+}
+
+/*
+ * ext4_xattr_delete_inode()
+ *
+ * Free extended attribute resources associated with this inode. Traverse
+ * all entries and decrement reference on any xattr inodes associated with this
+ * inode. This is called immediately before an inode is freed. We have exclusive
+ * access to the inode. If an orphan inode is deleted it will also release its
+ * references on xattr block and xattr inodes.
+ */
+int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
+			    struct ext4_xattr_inode_array **ea_inode_array,
+			    int extra_credits)
+{
+	struct buffer_head *bh = NULL;
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_iloc iloc = { .bh = NULL };
+	struct ext4_xattr_entry *entry;
+	struct inode *ea_inode;
+	int error;
+
+	error = ext4_journal_ensure_credits(handle, extra_credits,
+			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
+	if (error < 0) {
+		EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
+		goto cleanup;
+	}
+
+	if (ext4_has_feature_ea_inode(inode->i_sb) &&
+	    ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
+
+		error = ext4_get_inode_loc(inode, &iloc);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
+			goto cleanup;
+		}
+
+		error = ext4_journal_get_write_access(handle, iloc.bh);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "write access (error %d)",
+					 error);
+			goto cleanup;
+		}
+
+		header = IHDR(inode, ext4_raw_inode(&iloc));
+		if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
+			ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
+						     IFIRST(header),
+						     false /* block_csum */,
+						     ea_inode_array,
+						     extra_credits,
+						     false /* skip_quota */);
+	}
+
+	if (EXT4_I(inode)->i_file_acl) {
+		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+		if (IS_ERR(bh)) {
+			error = PTR_ERR(bh);
+			if (error == -EIO) {
+				EXT4_ERROR_INODE_ERR(inode, EIO,
+						     "block %llu read error",
+						     EXT4_I(inode)->i_file_acl);
+			}
+			bh = NULL;
+			goto cleanup;
+		}
+		error = ext4_xattr_check_block(inode, bh);
+		if (error)
+			goto cleanup;
+
+		if (ext4_has_feature_ea_inode(inode->i_sb)) {
+			for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
+			     entry = EXT4_XATTR_NEXT(entry)) {
+				if (!entry->e_value_inum)
+					continue;
+				error = ext4_xattr_inode_iget(inode,
+					      le32_to_cpu(entry->e_value_inum),
+					      le32_to_cpu(entry->e_hash),
+					      &ea_inode);
+				if (error)
+					continue;
+				ext4_xattr_inode_free_quota(inode, ea_inode,
+					      le32_to_cpu(entry->e_value_size));
+				iput(ea_inode);
+			}
+
+		}
+
+		ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
+					 extra_credits);
+		/*
+		 * Update i_file_acl value in the same transaction that releases
+		 * block.
+		 */
+		EXT4_I(inode)->i_file_acl = 0;
+		error = ext4_mark_inode_dirty(handle, inode);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
+					 error);
+			goto cleanup;
+		}
+		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
+	}
+	error = 0;
+cleanup:
+	brelse(iloc.bh);
+	brelse(bh);
+	return error;
+}
+
+void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
+{
+	int idx;
+
+	if (ea_inode_array == NULL)
+		return;
+
+	for (idx = 0; idx < ea_inode_array->count; ++idx)
+		iput(ea_inode_array->inodes[idx]);
+	kfree(ea_inode_array);
+}
+
+/*
+ * ext4_xattr_block_cache_insert()
+ *
+ * Create a new entry in the extended attribute block cache, and insert
+ * it unless such an entry is already in the cache.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+static void
+ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
+			      struct buffer_head *bh)
+{
+	struct ext4_xattr_header *header = BHDR(bh);
+	__u32 hash = le32_to_cpu(header->h_hash);
+	int reusable = le32_to_cpu(header->h_refcount) <
+		       EXT4_XATTR_REFCOUNT_MAX;
+	int error;
+
+	if (!ea_block_cache)
+		return;
+	error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
+				      bh->b_blocknr, reusable);
+	if (error) {
+		if (error == -EBUSY)
+			ea_bdebug(bh, "already in cache");
+	} else
+		ea_bdebug(bh, "inserting [%x]", (int)hash);
+}
+
+/*
+ * ext4_xattr_cmp()
+ *
+ * Compare two extended attribute blocks for equality.
+ *
+ * Returns 0 if the blocks are equal, 1 if they differ, and
+ * a negative error number on errors.
+ */
+static int
+ext4_xattr_cmp(struct ext4_xattr_header *header1,
+	       struct ext4_xattr_header *header2)
+{
+	struct ext4_xattr_entry *entry1, *entry2;
+
+	entry1 = ENTRY(header1+1);
+	entry2 = ENTRY(header2+1);
+	while (!IS_LAST_ENTRY(entry1)) {
+		if (IS_LAST_ENTRY(entry2))
+			return 1;
+		if (entry1->e_hash != entry2->e_hash ||
+		    entry1->e_name_index != entry2->e_name_index ||
+		    entry1->e_name_len != entry2->e_name_len ||
+		    entry1->e_value_size != entry2->e_value_size ||
+		    entry1->e_value_inum != entry2->e_value_inum ||
+		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
+			return 1;
+		if (!entry1->e_value_inum &&
+		    memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
+			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
+			   le32_to_cpu(entry1->e_value_size)))
+			return 1;
+
+		entry1 = EXT4_XATTR_NEXT(entry1);
+		entry2 = EXT4_XATTR_NEXT(entry2);
+	}
+	if (!IS_LAST_ENTRY(entry2))
+		return 1;
+	return 0;
+}
+
+/*
+ * ext4_xattr_block_cache_find()
+ *
+ * Find an identical extended attribute block.
+ *
+ * Returns a pointer to the block found, or NULL if such a block was
+ * not found or an error occurred.
+ */
+static struct buffer_head *
+ext4_xattr_block_cache_find(struct inode *inode,
+			    struct ext4_xattr_header *header,
+			    struct mb_cache_entry **pce)
+{
+	__u32 hash = le32_to_cpu(header->h_hash);
+	struct mb_cache_entry *ce;
+	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
+
+	if (!ea_block_cache)
+		return NULL;
+	if (!header->h_hash)
+		return NULL;  /* never share */
+	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
+	ce = mb_cache_entry_find_first(ea_block_cache, hash);
+	while (ce) {
+		struct buffer_head *bh;
+
+		bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
+		if (IS_ERR(bh)) {
+			if (PTR_ERR(bh) == -ENOMEM)
+				return NULL;
+			bh = NULL;
+			EXT4_ERROR_INODE(inode, "block %lu read error",
+					 (unsigned long)ce->e_value);
+		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
+			*pce = ce;
+			return bh;
+		}
+		brelse(bh);
+		ce = mb_cache_entry_find_next(ea_block_cache, ce);
+	}
+	return NULL;
+}
+
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+/*
+ * ext4_xattr_hash_entry()
+ *
+ * Compute the hash of an extended attribute.
+ */
+static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
+				    size_t value_count)
+{
+	__u32 hash = 0;
+
+	while (name_len--) {
+		hash = (hash << NAME_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
+		       *name++;
+	}
+	while (value_count--) {
+		hash = (hash << VALUE_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
+		       le32_to_cpu(*value++);
+	}
+	return cpu_to_le32(hash);
+}
+
+#undef NAME_HASH_SHIFT
+#undef VALUE_HASH_SHIFT
+
+#define BLOCK_HASH_SHIFT 16
+
+/*
+ * ext4_xattr_rehash()
+ *
+ * Re-compute the extended attribute hash value after an entry has changed.
+ */
+static void ext4_xattr_rehash(struct ext4_xattr_header *header)
+{
+	struct ext4_xattr_entry *here;
+	__u32 hash = 0;
+
+	here = ENTRY(header+1);
+	while (!IS_LAST_ENTRY(here)) {
+		if (!here->e_hash) {
+			/* Block is not shared if an entry's hash value == 0 */
+			hash = 0;
+			break;
+		}
+		hash = (hash << BLOCK_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
+		       le32_to_cpu(here->e_hash);
+		here = EXT4_XATTR_NEXT(here);
+	}
+	header->h_hash = cpu_to_le32(hash);
+}
+
+#undef BLOCK_HASH_SHIFT
+
+#define	HASH_BUCKET_BITS	10
+
+struct mb_cache *
+ext4_xattr_create_cache(void)
+{
+	return mb_cache_create(HASH_BUCKET_BITS);
+}
+
+void ext4_xattr_destroy_cache(struct mb_cache *cache)
+{
+	if (cache)
+		mb_cache_destroy(cache);
+}
+
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
new file mode 100644
index 000000000..e5e36bd11
--- /dev/null
+++ b/fs/ext4/xattr.h
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+  File: fs/ext4/xattr.h
+
+  On-disk format of extended attributes for the ext4 filesystem.
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define EXT4_XATTR_MAGIC		0xEA020000
+
+/* Maximum number of references to one attribute block */
+#define EXT4_XATTR_REFCOUNT_MAX		1024
+
+/* Name indexes */
+#define EXT4_XATTR_INDEX_USER			1
+#define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS	2
+#define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT	3
+#define EXT4_XATTR_INDEX_TRUSTED		4
+#define	EXT4_XATTR_INDEX_LUSTRE			5
+#define EXT4_XATTR_INDEX_SECURITY	        6
+#define EXT4_XATTR_INDEX_SYSTEM			7
+#define EXT4_XATTR_INDEX_RICHACL		8
+#define EXT4_XATTR_INDEX_ENCRYPTION		9
+#define EXT4_XATTR_INDEX_HURD			10 /* Reserved for Hurd */
+
+struct ext4_xattr_header {
+	__le32	h_magic;	/* magic number for identification */
+	__le32	h_refcount;	/* reference count */
+	__le32	h_blocks;	/* number of disk blocks used */
+	__le32	h_hash;		/* hash value of all attributes */
+	__le32	h_checksum;	/* crc32c(uuid+id+xattrblock) */
+				/* id = inum if refcount=1, blknum otherwise */
+	__u32	h_reserved[3];	/* zero right now */
+};
+
+struct ext4_xattr_ibody_header {
+	__le32	h_magic;	/* magic number for identification */
+};
+
+struct ext4_xattr_entry {
+	__u8	e_name_len;	/* length of name */
+	__u8	e_name_index;	/* attribute name index */
+	__le16	e_value_offs;	/* offset in disk block of value */
+	__le32	e_value_inum;	/* inode in which the value is stored */
+	__le32	e_value_size;	/* size of attribute value */
+	__le32	e_hash;		/* hash value of name and value */
+	char	e_name[];	/* attribute name */
+};
+
+#define EXT4_XATTR_PAD_BITS		2
+#define EXT4_XATTR_PAD		(1<<EXT4_XATTR_PAD_BITS)
+#define EXT4_XATTR_ROUND		(EXT4_XATTR_PAD-1)
+#define EXT4_XATTR_LEN(name_len) \
+	(((name_len) + EXT4_XATTR_ROUND + \
+	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
+#define EXT4_XATTR_NEXT(entry) \
+	((struct ext4_xattr_entry *)( \
+	 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
+#define EXT4_XATTR_SIZE(size) \
+	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
+
+#define IHDR(inode, raw_inode) \
+	((struct ext4_xattr_ibody_header *) \
+		((void *)raw_inode + \
+		EXT4_GOOD_OLD_INODE_SIZE + \
+		EXT4_I(inode)->i_extra_isize))
+#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
+
+/*
+ * XATTR_SIZE_MAX is currently 64k, but for the purposes of checking
+ * for file system consistency errors, we use a somewhat bigger value.
+ * This allows XATTR_SIZE_MAX to grow in the future, but by using this
+ * instead of INT_MAX for certain consistency checks, we don't need to
+ * worry about arithmetic overflows.  (Actually XATTR_SIZE_MAX is
+ * defined in include/uapi/linux/limits.h, so changing it is going
+ * not going to be trivial....)
+ */
+#define EXT4_XATTR_SIZE_MAX (1 << 24)
+
+/*
+ * The minimum size of EA value when you start storing it in an external inode
+ * size of block - size of header - size of 1 entry - 4 null bytes
+*/
+#define EXT4_XATTR_MIN_LARGE_EA_SIZE(b)					\
+	((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)
+
+#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
+#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
+#define BFIRST(bh) ENTRY(BHDR(bh)+1)
+#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define EXT4_ZERO_XATTR_VALUE ((void *)-1)
+
+/*
+ * If we want to add an xattr to the inode, we should make sure that
+ * i_extra_isize is not 0 and that the inode size is not less than
+ * EXT4_GOOD_OLD_INODE_SIZE + extra_isize + pad.
+ *   EXT4_GOOD_OLD_INODE_SIZE   extra_isize header   entry   pad  data
+ * |--------------------------|------------|------|---------|---|-------|
+ */
+#define EXT4_INODE_HAS_XATTR_SPACE(inode)				\
+	((EXT4_I(inode)->i_extra_isize != 0) &&				\
+	 (EXT4_GOOD_OLD_INODE_SIZE + EXT4_I(inode)->i_extra_isize +	\
+	  sizeof(struct ext4_xattr_ibody_header) + EXT4_XATTR_PAD <=	\
+	  EXT4_INODE_SIZE((inode)->i_sb)))
+
+struct ext4_xattr_info {
+	const char *name;
+	const void *value;
+	size_t value_len;
+	int name_index;
+	int in_inode;
+};
+
+struct ext4_xattr_search {
+	struct ext4_xattr_entry *first;
+	void *base;
+	void *end;
+	struct ext4_xattr_entry *here;
+	int not_found;
+};
+
+struct ext4_xattr_ibody_find {
+	struct ext4_xattr_search s;
+	struct ext4_iloc iloc;
+};
+
+struct ext4_xattr_inode_array {
+	unsigned int count;		/* # of used items in the array */
+	struct inode *inodes[];
+};
+
+extern const struct xattr_handler ext4_xattr_user_handler;
+extern const struct xattr_handler ext4_xattr_trusted_handler;
+extern const struct xattr_handler ext4_xattr_security_handler;
+extern const struct xattr_handler ext4_xattr_hurd_handler;
+
+#define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
+
+/*
+ * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes.
+ * The first is to signal that there the inline xattrs and data are
+ * taking up so much space that we might as well not keep trying to
+ * expand it.  The second is that xattr_sem is taken for writing, so
+ * we shouldn't try to recurse into the inode expansion.  For this
+ * second case, we need to make sure that we take save and restore the
+ * NO_EXPAND state flag appropriately.
+ */
+static inline void ext4_write_lock_xattr(struct inode *inode, int *save)
+{
+	down_write(&EXT4_I(inode)->xattr_sem);
+	*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
+	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
+}
+
+static inline int ext4_write_trylock_xattr(struct inode *inode, int *save)
+{
+	if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)
+		return 0;
+	*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
+	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
+	return 1;
+}
+
+static inline void ext4_write_unlock_xattr(struct inode *inode, int *save)
+{
+	if (*save == 0)
+		ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
+	up_write(&EXT4_I(inode)->xattr_sem);
+}
+
+extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
+
+extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
+extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
+extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  bool is_create, int *credits);
+extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
+				struct buffer_head *block_bh, size_t value_len,
+				bool is_create);
+
+extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
+				   struct ext4_xattr_inode_array **array,
+				   int extra_credits);
+extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
+
+extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
+			    struct ext4_inode *raw_inode, handle_t *handle);
+extern void ext4_evict_ea_inode(struct inode *inode);
+
+extern const struct xattr_handler *ext4_xattr_handlers[];
+
+extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
+				 struct ext4_xattr_ibody_find *is);
+extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
+				const char *name,
+				void *buffer, size_t buffer_size);
+extern int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
+				struct ext4_xattr_info *i,
+				struct ext4_xattr_ibody_find *is);
+
+extern struct mb_cache *ext4_xattr_create_cache(void);
+extern void ext4_xattr_destroy_cache(struct mb_cache *);
+
+#ifdef CONFIG_EXT4_FS_SECURITY
+extern int ext4_init_security(handle_t *handle, struct inode *inode,
+			      struct inode *dir, const struct qstr *qstr);
+#else
+static inline int ext4_init_security(handle_t *handle, struct inode *inode,
+				     struct inode *dir, const struct qstr *qstr)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_LOCKDEP
+extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
+#else
+static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
+#endif
+
+extern int ext4_get_inode_usage(struct inode *inode, qsize_t *usage);
diff --git a/fs/ext4/xattr_hurd.c b/fs/ext4/xattr_hurd.c
new file mode 100644
index 000000000..8cfa74a56
--- /dev/null
+++ b/fs/ext4/xattr_hurd.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/xattr_hurd.c
+ * Handler for extended gnu attributes for the Hurd.
+ *
+ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ * Copyright (C) 2020 by Jan (janneke) Nieuwenhuizen, <janneke@gnu.org>
+ */
+
+#include <linux/init.h>
+#include <linux/string.h>
+#include "ext4.h"
+#include "xattr.h"
+
+static bool
+ext4_xattr_hurd_list(struct dentry *dentry)
+{
+	return test_opt(dentry->d_sb, XATTR_USER);
+}
+
+static int
+ext4_xattr_hurd_get(const struct xattr_handler *handler,
+		    struct dentry *unused, struct inode *inode,
+		    const char *name, void *buffer, size_t size)
+{
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_HURD,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_hurd_set(const struct xattr_handler *handler,
+		    struct dentry *unused, struct inode *inode,
+		    const char *name, const void *value,
+		    size_t size, int flags)
+{
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+
+	return ext4_xattr_set(inode, EXT4_XATTR_INDEX_HURD,
+			      name, value, size, flags);
+}
+
+const struct xattr_handler ext4_xattr_hurd_handler = {
+	.prefix	= XATTR_HURD_PREFIX,
+	.list	= ext4_xattr_hurd_list,
+	.get	= ext4_xattr_hurd_get,
+	.set	= ext4_xattr_hurd_set,
+};
diff --git a/fs/ext4/xattr_security.c b/fs/ext4/xattr_security.c
new file mode 100644
index 000000000..197a9d8a1
--- /dev/null
+++ b/fs/ext4/xattr_security.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/xattr_security.c
+ * Handler for storing security labels as extended attributes.
+ */
+
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+
+static int
+ext4_xattr_security_get(const struct xattr_handler *handler,
+			struct dentry *unused, struct inode *inode,
+			const char *name, void *buffer, size_t size)
+{
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_SECURITY,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_security_set(const struct xattr_handler *handler,
+			struct dentry *unused, struct inode *inode,
+			const char *name, const void *value,
+			size_t size, int flags)
+{
+	return ext4_xattr_set(inode, EXT4_XATTR_INDEX_SECURITY,
+			      name, value, size, flags);
+}
+
+static int
+ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		void *fs_info)
+{
+	const struct xattr *xattr;
+	handle_t *handle = fs_info;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = ext4_xattr_set_handle(handle, inode,
+					    EXT4_XATTR_INDEX_SECURITY,
+					    xattr->name, xattr->value,
+					    xattr->value_len, XATTR_CREATE);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
+int
+ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
+		   const struct qstr *qstr)
+{
+	return security_inode_init_security(inode, dir, qstr,
+					    &ext4_initxattrs, handle);
+}
+
+const struct xattr_handler ext4_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.get	= ext4_xattr_security_get,
+	.set	= ext4_xattr_security_set,
+};
diff --git a/fs/ext4/xattr_trusted.c b/fs/ext4/xattr_trusted.c
new file mode 100644
index 000000000..e9389e5d7
--- /dev/null
+++ b/fs/ext4/xattr_trusted.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/xattr_trusted.c
+ * Handler for trusted extended attributes.
+ *
+ * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/string.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+
+static bool
+ext4_xattr_trusted_list(struct dentry *dentry)
+{
+	return capable(CAP_SYS_ADMIN);
+}
+
+static int
+ext4_xattr_trusted_get(const struct xattr_handler *handler,
+		       struct dentry *unused, struct inode *inode,
+		       const char *name, void *buffer, size_t size)
+{
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_TRUSTED,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_trusted_set(const struct xattr_handler *handler,
+		       struct dentry *unused, struct inode *inode,
+		       const char *name, const void *value,
+		       size_t size, int flags)
+{
+	return ext4_xattr_set(inode, EXT4_XATTR_INDEX_TRUSTED,
+			      name, value, size, flags);
+}
+
+const struct xattr_handler ext4_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.list	= ext4_xattr_trusted_list,
+	.get	= ext4_xattr_trusted_get,
+	.set	= ext4_xattr_trusted_set,
+};
diff --git a/fs/ext4/xattr_user.c b/fs/ext4/xattr_user.c
new file mode 100644
index 000000000..d4546184b
--- /dev/null
+++ b/fs/ext4/xattr_user.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/xattr_user.c
+ * Handler for extended user attributes.
+ *
+ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/string.h>
+#include <linux/fs.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+
+static bool
+ext4_xattr_user_list(struct dentry *dentry)
+{
+	return test_opt(dentry->d_sb, XATTR_USER);
+}
+
+static int
+ext4_xattr_user_get(const struct xattr_handler *handler,
+		    struct dentry *unused, struct inode *inode,
+		    const char *name, void *buffer, size_t size)
+{
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_USER,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_user_set(const struct xattr_handler *handler,
+		    struct dentry *unused, struct inode *inode,
+		    const char *name, const void *value,
+		    size_t size, int flags)
+{
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+	return ext4_xattr_set(inode, EXT4_XATTR_INDEX_USER,
+			      name, value, size, flags);
+}
+
+const struct xattr_handler ext4_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.list	= ext4_xattr_user_list,
+	.get	= ext4_xattr_user_get,
+	.set	= ext4_xattr_user_set,
+};