Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 6229 insertions, 0 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
new file mode 100644
index 000000000..bf120842a
--- /dev/null
+++ b/fs/ext4/super.c
@@ -0,0 +1,6229 @@
+// 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/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_sem -> sb_start_pagefault -> i_mmap_sem (r) -> transaction start ->
+ *   page lock -> i_data_sem (rw)
+ *
+ * buffered write path:
+ * sb_start_write -> i_mutex -> mmap_sem
+ * 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_sem
+ * 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)
+
+/*
+ * This works like sb_bread() 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.
+ */
+struct buffer_head *
+ext4_sb_bread(struct super_block *sb, sector_t block, int op_flags)
+{
+	struct buffer_head *bh = sb_getblk(sb, block);
+
+	if (bh == NULL)
+		return ERR_PTR(-ENOMEM);
+	if (buffer_uptodate(bh))
+		return bh;
+	ll_rw_block(REQ_OP_READ, REQ_META | op_flags, 1, &bh);
+	wait_on_buffer(bh);
+	if (buffer_uptodate(bh))
+		return bh;
+	put_bh(bh);
+	return ERR_PTR(-EIO);
+}
+
+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);
+}
+
+void *ext4_kvmalloc(size_t size, gfp_t flags)
+{
+	void *ret;
+
+	ret = kmalloc(size, flags | __GFP_NOWARN);
+	if (!ret)
+		ret = __vmalloc(size, flags, PAGE_KERNEL);
+	return ret;
+}
+
+void *ext4_kvzalloc(size_t size, gfp_t flags)
+{
+	void *ret;
+
+	ret = kzalloc(size, flags | __GFP_NOWARN);
+	if (!ret)
+		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
+	return ret;
+}
+
+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)
+
+static void __save_error_info(struct super_block *sb, 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;
+	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);
+	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;
+	}
+	/*
+	 * 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, const char *func,
+			    unsigned int line)
+{
+	__save_error_info(sb, func, line);
+	if (!bdev_read_only(sb->s_bdev))
+		ext4_commit_super(sb, 1);
+}
+
+/*
+ * 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);
+}
+
+static bool system_going_down(void)
+{
+	return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
+		|| system_state == SYSTEM_RESTART;
+}
+
+/* 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_SB(sb)->s_mount_flags |= 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)) {
+		if (EXT4_SB(sb)->s_journal &&
+		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR))
+			return;
+		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, 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, function, line);
+	ext4_handle_error(sb);
+}
+
+void __ext4_error_inode(struct inode *inode, const char *function,
+			unsigned int line, ext4_fsblk_t block,
+			const char *fmt, ...)
+{
+	va_list args;
+	struct va_format vaf;
+	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return;
+
+	trace_ext4_error(inode->i_sb, function, line);
+	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
+	es->s_last_error_block = cpu_to_le64(block);
+	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, 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 ext4_super_block *es;
+	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);
+	es = EXT4_SB(inode->i_sb)->s_es;
+	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
+	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, 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, 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, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
+		return;
+
+	save_error_info(sb, 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_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
+		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
+		/*
+		 * Make sure updated value of ->s_mount_flags will be visible
+		 * before ->s_flags update
+		 */
+		smp_wmb();
+		sb->s_flags |= SB_RDONLY;
+		if (EXT4_SB(sb)->s_journal)
+			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
+		save_error_info(sb, function, line);
+	}
+	if (test_opt(sb, ERRORS_PANIC) && !system_going_down()) {
+		if (EXT4_SB(sb)->s_journal &&
+		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR))
+			return;
+		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;
+
+	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);
+}
+
+#define ext4_warning_ratelimit(sb)					\
+		___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;
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
+		return;
+
+	trace_ext4_error(sb, function, line);
+	es->s_last_error_ino = cpu_to_le32(ino);
+	es->s_last_error_block = cpu_to_le64(block);
+	__save_error_info(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: 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 (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;
+	char b[BDEVNAME_SIZE];
+
+	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 %s: %ld",
+			__bdevname(dev, b), 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->journal_bdev;
+	if (bdev) {
+		ext4_blkdev_put(bdev);
+		sbi->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;
+
+	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, "Couldn't clean up the journal");
+	}
+
+	ext4_unregister_sysfs(sb);
+	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_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->journal_bdev && sbi->journal_bdev != sb->s_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.
+		 */
+		sync_blockdev(sbi->journal_bdev);
+		invalidate_bdev(sbi->journal_bdev);
+		ext4_blkdev_remove(sbi);
+	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
+	if (sbi->s_ea_block_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_block_cache);
+		sbi->s_ea_block_cache = NULL;
+	}
+	if (sbi->s_mmp_tsk)
+		kthread_stop(sbi->s_mmp_tsk);
+	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);
+	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);
+	spin_lock_init(&ei->i_raw_lock);
+	INIT_LIST_HEAD(&ei->i_prealloc_list);
+	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;
+	ei->i_da_metadata_calc_len = 0;
+	ei->i_da_metadata_calc_last_lblock = 0;
+	spin_lock_init(&(ei->i_block_reservation_lock));
+#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);
+	return &ei->vfs_inode;
+}
+
+static int ext4_drop_inode(struct inode *inode)
+{
+	int drop = generic_drop_inode(inode);
+
+	trace_ext4_drop_inode(inode, drop);
+	return drop;
+}
+
+static void ext4_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	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();
+	}
+	call_rcu(&inode->i_rcu, ext4_i_callback);
+}
+
+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);
+}
+
+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)
+{
+	invalidate_inode_buffers(inode);
+	clear_inode(inode);
+	dquot_drop(inode);
+	ext4_discard_preallocations(inode);
+	ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
+	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);
+}
+
+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,
+						wait & ~__GFP_DIRECT_RECLAIM);
+	return try_to_free_buffers(page);
+}
+
+#ifdef CONFIG_EXT4_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;
+
+	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);
+		}
+		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);
+		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 bool ext4_dummy_context(struct inode *inode)
+{
+	return DUMMY_ENCRYPTION_ENABLED(EXT4_SB(inode->i_sb));
+}
+
+static const struct fscrypt_operations ext4_cryptops = {
+	.key_prefix		= "ext4:",
+	.get_context		= ext4_get_context,
+	.set_context		= ext4_set_context,
+	.dummy_context		= ext4_dummy_context,
+	.empty_dir		= ext4_empty_dir,
+	.max_namelen		= EXT4_NAME_LEN,
+};
+#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 int ext4_get_next_id(struct super_block *sb, struct kqid *qid);
+
+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		= ext4_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,
+	.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_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_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,
+};
+
+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_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, "dioread_lock"},
+	{Opt_discard, "discard"},
+	{Opt_nodiscard, "nodiscard"},
+	{Opt_init_itable, "init_itable=%u"},
+	{Opt_init_itable, "init_itable"},
+	{Opt_noinit_itable, "noinit_itable"},
+	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
+	{Opt_test_dummy_encryption, "test_dummy_encryption"},
+	{Opt_nombcache, "nombcache"},
+	{Opt_nombcache, "no_mbcache"},	/* for backward compatibility */
+	{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
+
+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, MOPT_SET},
+	{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_GTE0},
+	{Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
+	{Opt_err, 0, 0}
+};
+
+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:
+		sbi->s_mount_flags |= 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;
+	}
+
+	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;
+		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;
+	} 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) {
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+		sbi->s_mount_flags |= EXT4_MF_TEST_DUMMY_ENCRYPTION;
+		ext4_msg(sb, KERN_WARNING,
+			 "Test dummy encryption mode enabled");
+#else
+		ext4_msg(sb, KERN_WARNING,
+			 "Test dummy encryption mount option ignored");
+#endif
+	} 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) {
+#ifdef CONFIG_FS_DAX
+		if (is_remount && test_opt(sb, DAX)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				"both data=journal and dax");
+			return -1;
+		}
+		if (is_remount && !(sbi->s_mount_opt & EXT4_MOUNT_DAX)) {
+			ext4_msg(sb, KERN_ERR, "can't change "
+					"dax mount option while remounting");
+			return -1;
+		}
+		ext4_msg(sb, KERN_WARNING,
+		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
+			sbi->s_mount_opt |= m->mount_opt;
+#else
+		ext4_msg(sb, KERN_INFO, "dax option not supported");
+		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 (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 *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_ERR, "can't mount with "
+				 "dioread_nolock if block size != PAGE_SIZE");
+			return 0;
+		}
+	}
+	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))
+			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");
+	if (DUMMY_ENCRYPTION_ENABLED(sbi))
+		SEQ_OPTS_PUTS("test_dummy_encryption");
+
+	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 < le16_to_cpu(sbi->s_es->s_desc_size))
+		crc = crc16(crc, (__u8 *)gdp + offset,
+			    le16_to_cpu(sbi->s_es->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;
+
+	/* small i_blocks in vfs inode? */
+	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
+		/*
+		 * CONFIG_LBDAF is not enabled implies the inode
+		 * i_block represent total blocks in 512 bytes
+		 * 32 == size of vfs inode i_blocks * 8
+		 */
+		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)
+{
+	loff_t res = EXT4_NDIR_BLOCKS;
+	int meta_blocks;
+	loff_t upper_limit;
+	/* 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 || sizeof(blkcnt_t) < sizeof(u64)) {
+		/*
+		 * !has_huge_files or CONFIG_LBDAF not enabled 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 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;
+	}
+
+	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;
+	}
+	/*
+	 * Large file size enabled file system can only be mounted
+	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
+	 */
+	if (ext4_has_feature_huge_file(sb)) {
+		if (sizeof(blkcnt_t) < sizeof(u64)) {
+			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
+				 "cannot be mounted RDWR without "
+				 "CONFIG_LBDAF");
+			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;
+	ext4_group_t group, ngroups;
+	struct super_block *sb;
+	int ret = 0;
+	u64 start_time;
+
+	sb = elr->lr_super;
+	ngroups = EXT4_SB(sb)->s_groups_count;
+
+	for (group = elr->lr_next_group; 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);
+		if (elr->lr_timeout == 0) {
+			elr->lr_timeout = nsecs_to_jiffies((ktime_get_real_ns() - start_time) *
+				  elr->lr_sbi->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)
+{
+	struct ext4_sb_info *sbi;
+
+	if (!elr)
+		return;
+
+	sbi = elr->lr_sbi;
+
+	list_del(&elr->lr_request);
+	sbi->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);
+
+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_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_li_request *elr;
+
+	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
+	if (!elr)
+		return NULL;
+
+	elr->lr_super = sb;
+	elr->lr_sbi = sbi;
+	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 (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->journal_bdev)
+		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
+	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, has_bigalloc;
+	__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;
+	}
+
+	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {
+		ext4_msg(sb, KERN_ERR, "unable to read superblock");
+		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
+	/* 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;
+
+	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
+	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
+	    blocksize > EXT4_MAX_BLOCK_SIZE) {
+		ext4_msg(sb, KERN_ERR,
+		       "Unsupported filesystem blocksize %d (%d log_block_size)",
+			 blocksize, le32_to_cpu(es->s_log_block_size));
+		goto failed_mount;
+	}
+
+	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;
+		} else {
+			sb->s_time_gran = NSEC_PER_SEC;
+		}
+	}
+	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;
+
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
+		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
+			    "with data=journal disables delayed "
+			    "allocation and O_DIRECT support!\n");
+		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, DIOREAD_NOLOCK)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "both data=journal and dioread_nolock");
+			goto failed_mount;
+		}
+		if (test_opt(sb, DAX)) {
+			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 (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;
+	}
+
+	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 (sbi->s_mount_opt & EXT4_MOUNT_DAX) {
+		if (ext4_has_feature_inline_data(sb)) {
+			ext4_msg(sb, KERN_ERR, "Cannot use DAX on a filesystem"
+					" that may contain inline data");
+			sbi->s_mount_opt &= ~EXT4_MOUNT_DAX;
+		}
+		if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
+			ext4_msg(sb, KERN_ERR,
+				"DAX unsupported by block device. Turning off DAX.");
+			sbi->s_mount_opt &= ~EXT4_MOUNT_DAX;
+		}
+	}
+
+	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) {
+		/* Validate the filesystem blocksize */
+		if (!sb_set_blocksize(sb, blocksize)) {
+			ext4_msg(sb, KERN_ERR, "bad block size %d",
+					blocksize);
+			goto failed_mount;
+		}
+
+		brelse(bh);
+		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
+		offset = do_div(logical_sb_block, blocksize);
+		bh = sb_bread_unmovable(sb, logical_sb_block);
+		if (!bh) {
+			ext4_msg(sb, KERN_ERR,
+			       "Can't read superblock on 2nd try");
+			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);
+	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);
+	has_bigalloc = ext4_has_feature_bigalloc(sb);
+	if (has_bigalloc) {
+		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");
+		if (sizeof(sector_t) < 8)
+			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
+		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);
+		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 = sb_bread_unmovable(sb, block);
+		if (!bh) {
+			ext4_msg(sb, KERN_ERR,
+			       "can't read group descriptor %d", i);
+			db_count = i;
+			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_EXT4_FS_ENCRYPTION
+	sb->s_cop = &ext4_cryptops;
+#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);
+
+	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))
+		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
+			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_mount_wq;
+	} else {
+		/* Nojournal mode, all journal mount options are illegal */
+		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_mount_wq;
+		}
+		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_mount_wq;
+		}
+		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_mount_wq;
+		}
+		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_mount_wq;
+		}
+		sbi->s_def_mount_opt &= ~EXT4_MOUNT_JOURNAL_CHECKSUM;
+		clear_opt(sb, JOURNAL_CHECKSUM);
+		clear_opt(sb, DATA_FLAGS);
+		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;
+	}
+
+	/* 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_commit_callback = ext4_journal_commit_callback;
+
+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 ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
+	    (blocksize != PAGE_SIZE)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Unsupported blocksize for fs encryption");
+		goto failed_mount_wq;
+	}
+
+	if (DUMMY_ENCRYPTION_ENABLED(sbi) && !sb_rdonly(sb) &&
+	    !ext4_has_feature_encrypt(sb)) {
+		ext4_set_feature_encrypt(sb);
+		ext4_commit_super(sb, 1);
+	}
+
+	/*
+	 * 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;
+	}
+	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_ext_init(sb);
+	err = ext4_mb_init(sb);
+	if (err) {
+		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
+			 err);
+		goto failed_mount5;
+	}
+
+	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_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 */
+
+	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);
+
+	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_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:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
+	if (sbi->s_ea_block_cache) {
+		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);
+	if (sbi->s_mmp_tsk)
+		kthread_stop(sbi->s_mmp_tsk);
+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_QUOTA
+	for (i = 0; i < EXT4_MAXQUOTAS; i++)
+		kfree(sbi->s_qf_names[i]);
+#endif
+	ext4_blkdev_remove(sbi);
+	brelse(bh);
+out_fail:
+	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;
+
+	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)) {
+		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;
+	ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
+	wait_on_buffer(journal->j_sb_buffer);
+	if (!buffer_uptodate(journal->j_sb_buffer)) {
+		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)->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, NULL);
+		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;
+	int enable_quota = 0;
+	ext4_group_t g;
+	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
+	int err = 0;
+#ifdef CONFIG_QUOTA
+	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 (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
+		ext4_abort(sb, "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 (sbi->s_mount_flags & 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);
+			}
+			if (sbi->s_mmp_tsk)
+				kthread_stop(sbi->s_mmp_tsk);
+		} 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);
+
+			err = ext4_setup_super(sb, es, 0);
+			if (err)
+				goto restore_opts;
+
+			sb->s_flags &= ~SB_RDONLY;
+			if (ext4_has_feature_mmp(sb))
+				if (ext4_multi_mount_protect(sb,
+						le64_to_cpu(es->s_mmp_block))) {
+					err = -EROFS;
+					goto restore_opts;
+				}
+			enable_quota = 1;
+		}
+	}
+
+	/*
+	 * 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);
+	}
+
+	/*
+	 * 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->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
+	/* Release old quota file names */
+	for (i = 0; i < EXT4_MAXQUOTAS; i++)
+		kfree(old_opts.s_qf_names[i]);
+	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;
+		}
+	}
+#endif
+	if (!test_opt(sb, BLOCK_VALIDITY) && sbi->system_blks)
+		ext4_release_system_zone(sb);
+
+	/*
+	 * 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:
+	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->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
+	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 = (dquot->dq_dqb.dqb_bsoftlimit ?
+		 dquot->dq_dqb.dqb_bsoftlimit :
+		 dquot->dq_dqb.dqb_bhardlimit) >> 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 = dquot->dq_dqb.dqb_isoftlimit ?
+		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.val[0] = fsid & 0xFFFFFFFFUL;
+	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
+
+#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(d_inode(sb->s_root), 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);
+		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 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;
+
+	qf_inode = ext4_iget(sb, qf_inums[type], EXT4_IGET_SPECIAL);
+	if (IS_ERR(qf_inode)) {
+		ext4_error(sb, "Bad quota inode # %lu", qf_inums[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_enable(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). Please run "
+					"e2fsck to fix.", type, err);
+				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))
+		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);
+	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, 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 (IS_ERR(bh) && (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;
+		ext4_mark_inode_dirty(handle, inode);
+	}
+	return len;
+}
+
+static int ext4_get_next_id(struct super_block *sb, struct kqid *qid)
+{
+	const struct quota_format_ops	*ops;
+
+	if (!sb_has_quota_loaded(sb, qid->type))
+		return -ESRCH;
+	ops = sb_dqopt(sb)->ops[qid->type];
+	if (!ops || !ops->get_next_id)
+		return -ENOSYS;
+	return dquot_get_next_id(sb, qid);
+}
+#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_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;
+	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();
+	destroy_inodecache();
+out1:
+	ext4_exit_mballoc();
+out2:
+	ext4_exit_sysfs();
+out3:
+	ext4_exit_system_zone();
+out4:
+	ext4_exit_pageio();
+out5:
+	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);
+	destroy_inodecache();
+	ext4_exit_mballoc();
+	ext4_exit_sysfs();
+	ext4_exit_system_zone();
+	ext4_exit_pageio();
+	ext4_exit_es();
+}
+
+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)