Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 1292 insertions, 0 deletions

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
new file mode 100644
index 0000000000..1a8bd59934
--- /dev/null
+++ b/fs/nilfs2/inode.c
@@ -0,0 +1,1292 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * NILFS inode operations.
+ *
+ * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * Written by Ryusuke Konishi.
+ *
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/gfp.h>
+#include <linux/mpage.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/uio.h>
+#include <linux/fiemap.h>
+#include "nilfs.h"
+#include "btnode.h"
+#include "segment.h"
+#include "page.h"
+#include "mdt.h"
+#include "cpfile.h"
+#include "ifile.h"
+
+/**
+ * struct nilfs_iget_args - arguments used during comparison between inodes
+ * @ino: inode number
+ * @cno: checkpoint number
+ * @root: pointer on NILFS root object (mounted checkpoint)
+ * @for_gc: inode for GC flag
+ * @for_btnc: inode for B-tree node cache flag
+ * @for_shadow: inode for shadowed page cache flag
+ */
+struct nilfs_iget_args {
+	u64 ino;
+	__u64 cno;
+	struct nilfs_root *root;
+	bool for_gc;
+	bool for_btnc;
+	bool for_shadow;
+};
+
+static int nilfs_iget_test(struct inode *inode, void *opaque);
+
+void nilfs_inode_add_blocks(struct inode *inode, int n)
+{
+	struct nilfs_root *root = NILFS_I(inode)->i_root;
+
+	inode_add_bytes(inode, i_blocksize(inode) * n);
+	if (root)
+		atomic64_add(n, &root->blocks_count);
+}
+
+void nilfs_inode_sub_blocks(struct inode *inode, int n)
+{
+	struct nilfs_root *root = NILFS_I(inode)->i_root;
+
+	inode_sub_bytes(inode, i_blocksize(inode) * n);
+	if (root)
+		atomic64_sub(n, &root->blocks_count);
+}
+
+/**
+ * nilfs_get_block() - get a file block on the filesystem (callback function)
+ * @inode: inode struct of the target file
+ * @blkoff: file block number
+ * @bh_result: buffer head to be mapped on
+ * @create: indicate whether allocating the block or not when it has not
+ *      been allocated yet.
+ *
+ * This function does not issue actual read request of the specified data
+ * block. It is done by VFS.
+ */
+int nilfs_get_block(struct inode *inode, sector_t blkoff,
+		    struct buffer_head *bh_result, int create)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+	__u64 blknum = 0;
+	int err = 0, ret;
+	unsigned int maxblocks = bh_result->b_size >> inode->i_blkbits;
+
+	down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+	ret = nilfs_bmap_lookup_contig(ii->i_bmap, blkoff, &blknum, maxblocks);
+	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+	if (ret >= 0) {	/* found */
+		map_bh(bh_result, inode->i_sb, blknum);
+		if (ret > 0)
+			bh_result->b_size = (ret << inode->i_blkbits);
+		goto out;
+	}
+	/* data block was not found */
+	if (ret == -ENOENT && create) {
+		struct nilfs_transaction_info ti;
+
+		bh_result->b_blocknr = 0;
+		err = nilfs_transaction_begin(inode->i_sb, &ti, 1);
+		if (unlikely(err))
+			goto out;
+		err = nilfs_bmap_insert(ii->i_bmap, blkoff,
+					(unsigned long)bh_result);
+		if (unlikely(err != 0)) {
+			if (err == -EEXIST) {
+				/*
+				 * The get_block() function could be called
+				 * from multiple callers for an inode.
+				 * However, the page having this block must
+				 * be locked in this case.
+				 */
+				nilfs_warn(inode->i_sb,
+					   "%s (ino=%lu): a race condition while inserting a data block at offset=%llu",
+					   __func__, inode->i_ino,
+					   (unsigned long long)blkoff);
+				err = 0;
+			}
+			nilfs_transaction_abort(inode->i_sb);
+			goto out;
+		}
+		nilfs_mark_inode_dirty_sync(inode);
+		nilfs_transaction_commit(inode->i_sb); /* never fails */
+		/* Error handling should be detailed */
+		set_buffer_new(bh_result);
+		set_buffer_delay(bh_result);
+		map_bh(bh_result, inode->i_sb, 0);
+		/* Disk block number must be changed to proper value */
+
+	} else if (ret == -ENOENT) {
+		/*
+		 * not found is not error (e.g. hole); must return without
+		 * the mapped state flag.
+		 */
+		;
+	} else {
+		err = ret;
+	}
+
+ out:
+	return err;
+}
+
+/**
+ * nilfs_read_folio() - implement read_folio() method of nilfs_aops {}
+ * address_space_operations.
+ * @file: file struct of the file to be read
+ * @folio: the folio to be read
+ */
+static int nilfs_read_folio(struct file *file, struct folio *folio)
+{
+	return mpage_read_folio(folio, nilfs_get_block);
+}
+
+static void nilfs_readahead(struct readahead_control *rac)
+{
+	mpage_readahead(rac, nilfs_get_block);
+}
+
+static int nilfs_writepages(struct address_space *mapping,
+			    struct writeback_control *wbc)
+{
+	struct inode *inode = mapping->host;
+	int err = 0;
+
+	if (sb_rdonly(inode->i_sb)) {
+		nilfs_clear_dirty_pages(mapping, false);
+		return -EROFS;
+	}
+
+	if (wbc->sync_mode == WB_SYNC_ALL)
+		err = nilfs_construct_dsync_segment(inode->i_sb, inode,
+						    wbc->range_start,
+						    wbc->range_end);
+	return err;
+}
+
+static int nilfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	int err;
+
+	if (sb_rdonly(inode->i_sb)) {
+		/*
+		 * It means that filesystem was remounted in read-only
+		 * mode because of error or metadata corruption. But we
+		 * have dirty pages that try to be flushed in background.
+		 * So, here we simply discard this dirty page.
+		 */
+		nilfs_clear_dirty_page(page, false);
+		unlock_page(page);
+		return -EROFS;
+	}
+
+	redirty_page_for_writepage(wbc, page);
+	unlock_page(page);
+
+	if (wbc->sync_mode == WB_SYNC_ALL) {
+		err = nilfs_construct_segment(inode->i_sb);
+		if (unlikely(err))
+			return err;
+	} else if (wbc->for_reclaim)
+		nilfs_flush_segment(inode->i_sb, inode->i_ino);
+
+	return 0;
+}
+
+static bool nilfs_dirty_folio(struct address_space *mapping,
+		struct folio *folio)
+{
+	struct inode *inode = mapping->host;
+	struct buffer_head *head;
+	unsigned int nr_dirty = 0;
+	bool ret = filemap_dirty_folio(mapping, folio);
+
+	/*
+	 * The page may not be locked, eg if called from try_to_unmap_one()
+	 */
+	spin_lock(&mapping->private_lock);
+	head = folio_buffers(folio);
+	if (head) {
+		struct buffer_head *bh = head;
+
+		do {
+			/* Do not mark hole blocks dirty */
+			if (buffer_dirty(bh) || !buffer_mapped(bh))
+				continue;
+
+			set_buffer_dirty(bh);
+			nr_dirty++;
+		} while (bh = bh->b_this_page, bh != head);
+	} else if (ret) {
+		nr_dirty = 1 << (folio_shift(folio) - inode->i_blkbits);
+	}
+	spin_unlock(&mapping->private_lock);
+
+	if (nr_dirty)
+		nilfs_set_file_dirty(inode, nr_dirty);
+	return ret;
+}
+
+void nilfs_write_failed(struct address_space *mapping, loff_t to)
+{
+	struct inode *inode = mapping->host;
+
+	if (to > inode->i_size) {
+		truncate_pagecache(inode, inode->i_size);
+		nilfs_truncate(inode);
+	}
+}
+
+static int nilfs_write_begin(struct file *file, struct address_space *mapping,
+			     loff_t pos, unsigned len,
+			     struct page **pagep, void **fsdata)
+
+{
+	struct inode *inode = mapping->host;
+	int err = nilfs_transaction_begin(inode->i_sb, NULL, 1);
+
+	if (unlikely(err))
+		return err;
+
+	err = block_write_begin(mapping, pos, len, pagep, nilfs_get_block);
+	if (unlikely(err)) {
+		nilfs_write_failed(mapping, pos + len);
+		nilfs_transaction_abort(inode->i_sb);
+	}
+	return err;
+}
+
+static int nilfs_write_end(struct file *file, struct address_space *mapping,
+			   loff_t pos, unsigned len, unsigned copied,
+			   struct page *page, void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	unsigned int start = pos & (PAGE_SIZE - 1);
+	unsigned int nr_dirty;
+	int err;
+
+	nr_dirty = nilfs_page_count_clean_buffers(page, start,
+						  start + copied);
+	copied = generic_write_end(file, mapping, pos, len, copied, page,
+				   fsdata);
+	nilfs_set_file_dirty(inode, nr_dirty);
+	err = nilfs_transaction_commit(inode->i_sb);
+	return err ? : copied;
+}
+
+static ssize_t
+nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	if (iov_iter_rw(iter) == WRITE)
+		return 0;
+
+	/* Needs synchronization with the cleaner */
+	return blockdev_direct_IO(iocb, inode, iter, nilfs_get_block);
+}
+
+const struct address_space_operations nilfs_aops = {
+	.writepage		= nilfs_writepage,
+	.read_folio		= nilfs_read_folio,
+	.writepages		= nilfs_writepages,
+	.dirty_folio		= nilfs_dirty_folio,
+	.readahead		= nilfs_readahead,
+	.write_begin		= nilfs_write_begin,
+	.write_end		= nilfs_write_end,
+	.invalidate_folio	= block_invalidate_folio,
+	.direct_IO		= nilfs_direct_IO,
+	.is_partially_uptodate  = block_is_partially_uptodate,
+};
+
+static int nilfs_insert_inode_locked(struct inode *inode,
+				     struct nilfs_root *root,
+				     unsigned long ino)
+{
+	struct nilfs_iget_args args = {
+		.ino = ino, .root = root, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = false
+	};
+
+	return insert_inode_locked4(inode, ino, nilfs_iget_test, &args);
+}
+
+struct inode *nilfs_new_inode(struct inode *dir, umode_t mode)
+{
+	struct super_block *sb = dir->i_sb;
+	struct the_nilfs *nilfs = sb->s_fs_info;
+	struct inode *inode;
+	struct nilfs_inode_info *ii;
+	struct nilfs_root *root;
+	struct buffer_head *bh;
+	int err = -ENOMEM;
+	ino_t ino;
+
+	inode = new_inode(sb);
+	if (unlikely(!inode))
+		goto failed;
+
+	mapping_set_gfp_mask(inode->i_mapping,
+			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
+
+	root = NILFS_I(dir)->i_root;
+	ii = NILFS_I(inode);
+	ii->i_state = BIT(NILFS_I_NEW);
+	ii->i_root = root;
+
+	err = nilfs_ifile_create_inode(root->ifile, &ino, &bh);
+	if (unlikely(err))
+		goto failed_ifile_create_inode;
+	/* reference count of i_bh inherits from nilfs_mdt_read_block() */
+
+	if (unlikely(ino < NILFS_USER_INO)) {
+		nilfs_warn(sb,
+			   "inode bitmap is inconsistent for reserved inodes");
+		do {
+			brelse(bh);
+			err = nilfs_ifile_create_inode(root->ifile, &ino, &bh);
+			if (unlikely(err))
+				goto failed_ifile_create_inode;
+		} while (ino < NILFS_USER_INO);
+
+		nilfs_info(sb, "repaired inode bitmap for reserved inodes");
+	}
+	ii->i_bh = bh;
+
+	atomic64_inc(&root->inodes_count);
+	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
+	inode->i_ino = ino;
+	inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode);
+
+	if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) {
+		err = nilfs_bmap_read(ii->i_bmap, NULL);
+		if (err < 0)
+			goto failed_after_creation;
+
+		set_bit(NILFS_I_BMAP, &ii->i_state);
+		/* No lock is needed; iget() ensures it. */
+	}
+
+	ii->i_flags = nilfs_mask_flags(
+		mode, NILFS_I(dir)->i_flags & NILFS_FL_INHERITED);
+
+	/* ii->i_file_acl = 0; */
+	/* ii->i_dir_acl = 0; */
+	ii->i_dir_start_lookup = 0;
+	nilfs_set_inode_flags(inode);
+	spin_lock(&nilfs->ns_next_gen_lock);
+	inode->i_generation = nilfs->ns_next_generation++;
+	spin_unlock(&nilfs->ns_next_gen_lock);
+	if (nilfs_insert_inode_locked(inode, root, ino) < 0) {
+		err = -EIO;
+		goto failed_after_creation;
+	}
+
+	err = nilfs_init_acl(inode, dir);
+	if (unlikely(err))
+		/*
+		 * Never occur.  When supporting nilfs_init_acl(),
+		 * proper cancellation of above jobs should be considered.
+		 */
+		goto failed_after_creation;
+
+	return inode;
+
+ failed_after_creation:
+	clear_nlink(inode);
+	if (inode->i_state & I_NEW)
+		unlock_new_inode(inode);
+	iput(inode);  /*
+		       * raw_inode will be deleted through
+		       * nilfs_evict_inode().
+		       */
+	goto failed;
+
+ failed_ifile_create_inode:
+	make_bad_inode(inode);
+	iput(inode);
+ failed:
+	return ERR_PTR(err);
+}
+
+void nilfs_set_inode_flags(struct inode *inode)
+{
+	unsigned int flags = NILFS_I(inode)->i_flags;
+	unsigned int new_fl = 0;
+
+	if (flags & FS_SYNC_FL)
+		new_fl |= S_SYNC;
+	if (flags & FS_APPEND_FL)
+		new_fl |= S_APPEND;
+	if (flags & FS_IMMUTABLE_FL)
+		new_fl |= S_IMMUTABLE;
+	if (flags & FS_NOATIME_FL)
+		new_fl |= S_NOATIME;
+	if (flags & FS_DIRSYNC_FL)
+		new_fl |= S_DIRSYNC;
+	inode_set_flags(inode, new_fl, S_SYNC | S_APPEND | S_IMMUTABLE |
+			S_NOATIME | S_DIRSYNC);
+}
+
+int nilfs_read_inode_common(struct inode *inode,
+			    struct nilfs_inode *raw_inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	int err;
+
+	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
+	i_uid_write(inode, le32_to_cpu(raw_inode->i_uid));
+	i_gid_write(inode, le32_to_cpu(raw_inode->i_gid));
+	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
+	inode->i_size = le64_to_cpu(raw_inode->i_size);
+	inode->i_atime.tv_sec = le64_to_cpu(raw_inode->i_mtime);
+	inode_set_ctime(inode, le64_to_cpu(raw_inode->i_ctime),
+			le32_to_cpu(raw_inode->i_ctime_nsec));
+	inode->i_mtime.tv_sec = le64_to_cpu(raw_inode->i_mtime);
+	inode->i_atime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);
+	inode->i_mtime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);
+	if (nilfs_is_metadata_file_inode(inode) && !S_ISREG(inode->i_mode))
+		return -EIO; /* this inode is for metadata and corrupted */
+	if (inode->i_nlink == 0)
+		return -ESTALE; /* this inode is deleted */
+
+	inode->i_blocks = le64_to_cpu(raw_inode->i_blocks);
+	ii->i_flags = le32_to_cpu(raw_inode->i_flags);
+#if 0
+	ii->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
+	ii->i_dir_acl = S_ISREG(inode->i_mode) ?
+		0 : le32_to_cpu(raw_inode->i_dir_acl);
+#endif
+	ii->i_dir_start_lookup = 0;
+	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
+
+	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+	    S_ISLNK(inode->i_mode)) {
+		err = nilfs_bmap_read(ii->i_bmap, raw_inode);
+		if (err < 0)
+			return err;
+		set_bit(NILFS_I_BMAP, &ii->i_state);
+		/* No lock is needed; iget() ensures it. */
+	}
+	return 0;
+}
+
+static int __nilfs_read_inode(struct super_block *sb,
+			      struct nilfs_root *root, unsigned long ino,
+			      struct inode *inode)
+{
+	struct the_nilfs *nilfs = sb->s_fs_info;
+	struct buffer_head *bh;
+	struct nilfs_inode *raw_inode;
+	int err;
+
+	down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+	err = nilfs_ifile_get_inode_block(root->ifile, ino, &bh);
+	if (unlikely(err))
+		goto bad_inode;
+
+	raw_inode = nilfs_ifile_map_inode(root->ifile, ino, bh);
+
+	err = nilfs_read_inode_common(inode, raw_inode);
+	if (err)
+		goto failed_unmap;
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = &nilfs_file_inode_operations;
+		inode->i_fop = &nilfs_file_operations;
+		inode->i_mapping->a_ops = &nilfs_aops;
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = &nilfs_dir_inode_operations;
+		inode->i_fop = &nilfs_dir_operations;
+		inode->i_mapping->a_ops = &nilfs_aops;
+	} else if (S_ISLNK(inode->i_mode)) {
+		inode->i_op = &nilfs_symlink_inode_operations;
+		inode_nohighmem(inode);
+		inode->i_mapping->a_ops = &nilfs_aops;
+	} else {
+		inode->i_op = &nilfs_special_inode_operations;
+		init_special_inode(
+			inode, inode->i_mode,
+			huge_decode_dev(le64_to_cpu(raw_inode->i_device_code)));
+	}
+	nilfs_ifile_unmap_inode(root->ifile, ino, bh);
+	brelse(bh);
+	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+	nilfs_set_inode_flags(inode);
+	mapping_set_gfp_mask(inode->i_mapping,
+			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
+	return 0;
+
+ failed_unmap:
+	nilfs_ifile_unmap_inode(root->ifile, ino, bh);
+	brelse(bh);
+
+ bad_inode:
+	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+	return err;
+}
+
+static int nilfs_iget_test(struct inode *inode, void *opaque)
+{
+	struct nilfs_iget_args *args = opaque;
+	struct nilfs_inode_info *ii;
+
+	if (args->ino != inode->i_ino || args->root != NILFS_I(inode)->i_root)
+		return 0;
+
+	ii = NILFS_I(inode);
+	if (test_bit(NILFS_I_BTNC, &ii->i_state)) {
+		if (!args->for_btnc)
+			return 0;
+	} else if (args->for_btnc) {
+		return 0;
+	}
+	if (test_bit(NILFS_I_SHADOW, &ii->i_state)) {
+		if (!args->for_shadow)
+			return 0;
+	} else if (args->for_shadow) {
+		return 0;
+	}
+
+	if (!test_bit(NILFS_I_GCINODE, &ii->i_state))
+		return !args->for_gc;
+
+	return args->for_gc && args->cno == ii->i_cno;
+}
+
+static int nilfs_iget_set(struct inode *inode, void *opaque)
+{
+	struct nilfs_iget_args *args = opaque;
+
+	inode->i_ino = args->ino;
+	NILFS_I(inode)->i_cno = args->cno;
+	NILFS_I(inode)->i_root = args->root;
+	if (args->root && args->ino == NILFS_ROOT_INO)
+		nilfs_get_root(args->root);
+
+	if (args->for_gc)
+		NILFS_I(inode)->i_state = BIT(NILFS_I_GCINODE);
+	if (args->for_btnc)
+		NILFS_I(inode)->i_state |= BIT(NILFS_I_BTNC);
+	if (args->for_shadow)
+		NILFS_I(inode)->i_state |= BIT(NILFS_I_SHADOW);
+	return 0;
+}
+
+struct inode *nilfs_ilookup(struct super_block *sb, struct nilfs_root *root,
+			    unsigned long ino)
+{
+	struct nilfs_iget_args args = {
+		.ino = ino, .root = root, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = false
+	};
+
+	return ilookup5(sb, ino, nilfs_iget_test, &args);
+}
+
+struct inode *nilfs_iget_locked(struct super_block *sb, struct nilfs_root *root,
+				unsigned long ino)
+{
+	struct nilfs_iget_args args = {
+		.ino = ino, .root = root, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = false
+	};
+
+	return iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
+}
+
+struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
+			 unsigned long ino)
+{
+	struct inode *inode;
+	int err;
+
+	inode = nilfs_iget_locked(sb, root, ino);
+	if (unlikely(!inode))
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	err = __nilfs_read_inode(sb, root, ino, inode);
+	if (unlikely(err)) {
+		iget_failed(inode);
+		return ERR_PTR(err);
+	}
+	unlock_new_inode(inode);
+	return inode;
+}
+
+struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
+				__u64 cno)
+{
+	struct nilfs_iget_args args = {
+		.ino = ino, .root = NULL, .cno = cno, .for_gc = true,
+		.for_btnc = false, .for_shadow = false
+	};
+	struct inode *inode;
+	int err;
+
+	inode = iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
+	if (unlikely(!inode))
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	err = nilfs_init_gcinode(inode);
+	if (unlikely(err)) {
+		iget_failed(inode);
+		return ERR_PTR(err);
+	}
+	unlock_new_inode(inode);
+	return inode;
+}
+
+/**
+ * nilfs_attach_btree_node_cache - attach a B-tree node cache to the inode
+ * @inode: inode object
+ *
+ * nilfs_attach_btree_node_cache() attaches a B-tree node cache to @inode,
+ * or does nothing if the inode already has it.  This function allocates
+ * an additional inode to maintain page cache of B-tree nodes one-on-one.
+ *
+ * Return Value: On success, 0 is returned. On errors, one of the following
+ * negative error code is returned.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ */
+int nilfs_attach_btree_node_cache(struct inode *inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct inode *btnc_inode;
+	struct nilfs_iget_args args;
+
+	if (ii->i_assoc_inode)
+		return 0;
+
+	args.ino = inode->i_ino;
+	args.root = ii->i_root;
+	args.cno = ii->i_cno;
+	args.for_gc = test_bit(NILFS_I_GCINODE, &ii->i_state) != 0;
+	args.for_btnc = true;
+	args.for_shadow = test_bit(NILFS_I_SHADOW, &ii->i_state) != 0;
+
+	btnc_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
+				  nilfs_iget_set, &args);
+	if (unlikely(!btnc_inode))
+		return -ENOMEM;
+	if (btnc_inode->i_state & I_NEW) {
+		nilfs_init_btnc_inode(btnc_inode);
+		unlock_new_inode(btnc_inode);
+	}
+	NILFS_I(btnc_inode)->i_assoc_inode = inode;
+	NILFS_I(btnc_inode)->i_bmap = ii->i_bmap;
+	ii->i_assoc_inode = btnc_inode;
+
+	return 0;
+}
+
+/**
+ * nilfs_detach_btree_node_cache - detach the B-tree node cache from the inode
+ * @inode: inode object
+ *
+ * nilfs_detach_btree_node_cache() detaches the B-tree node cache and its
+ * holder inode bound to @inode, or does nothing if @inode doesn't have it.
+ */
+void nilfs_detach_btree_node_cache(struct inode *inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct inode *btnc_inode = ii->i_assoc_inode;
+
+	if (btnc_inode) {
+		NILFS_I(btnc_inode)->i_assoc_inode = NULL;
+		ii->i_assoc_inode = NULL;
+		iput(btnc_inode);
+	}
+}
+
+/**
+ * nilfs_iget_for_shadow - obtain inode for shadow mapping
+ * @inode: inode object that uses shadow mapping
+ *
+ * nilfs_iget_for_shadow() allocates a pair of inodes that holds page
+ * caches for shadow mapping.  The page cache for data pages is set up
+ * in one inode and the one for b-tree node pages is set up in the
+ * other inode, which is attached to the former inode.
+ *
+ * Return Value: On success, a pointer to the inode for data pages is
+ * returned. On errors, one of the following negative error code is returned
+ * in a pointer type.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ */
+struct inode *nilfs_iget_for_shadow(struct inode *inode)
+{
+	struct nilfs_iget_args args = {
+		.ino = inode->i_ino, .root = NULL, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = true
+	};
+	struct inode *s_inode;
+	int err;
+
+	s_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
+			       nilfs_iget_set, &args);
+	if (unlikely(!s_inode))
+		return ERR_PTR(-ENOMEM);
+	if (!(s_inode->i_state & I_NEW))
+		return inode;
+
+	NILFS_I(s_inode)->i_flags = 0;
+	memset(NILFS_I(s_inode)->i_bmap, 0, sizeof(struct nilfs_bmap));
+	mapping_set_gfp_mask(s_inode->i_mapping, GFP_NOFS);
+
+	err = nilfs_attach_btree_node_cache(s_inode);
+	if (unlikely(err)) {
+		iget_failed(s_inode);
+		return ERR_PTR(err);
+	}
+	unlock_new_inode(s_inode);
+	return s_inode;
+}
+
+void nilfs_write_inode_common(struct inode *inode,
+			      struct nilfs_inode *raw_inode, int has_bmap)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+
+	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
+	raw_inode->i_uid = cpu_to_le32(i_uid_read(inode));
+	raw_inode->i_gid = cpu_to_le32(i_gid_read(inode));
+	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
+	raw_inode->i_size = cpu_to_le64(inode->i_size);
+	raw_inode->i_ctime = cpu_to_le64(inode_get_ctime(inode).tv_sec);
+	raw_inode->i_mtime = cpu_to_le64(inode->i_mtime.tv_sec);
+	raw_inode->i_ctime_nsec = cpu_to_le32(inode_get_ctime(inode).tv_nsec);
+	raw_inode->i_mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
+	raw_inode->i_blocks = cpu_to_le64(inode->i_blocks);
+
+	raw_inode->i_flags = cpu_to_le32(ii->i_flags);
+	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
+
+	if (NILFS_ROOT_METADATA_FILE(inode->i_ino)) {
+		struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+
+		/* zero-fill unused portion in the case of super root block */
+		raw_inode->i_xattr = 0;
+		raw_inode->i_pad = 0;
+		memset((void *)raw_inode + sizeof(*raw_inode), 0,
+		       nilfs->ns_inode_size - sizeof(*raw_inode));
+	}
+
+	if (has_bmap)
+		nilfs_bmap_write(ii->i_bmap, raw_inode);
+	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+		raw_inode->i_device_code =
+			cpu_to_le64(huge_encode_dev(inode->i_rdev));
+	/*
+	 * When extending inode, nilfs->ns_inode_size should be checked
+	 * for substitutions of appended fields.
+	 */
+}
+
+void nilfs_update_inode(struct inode *inode, struct buffer_head *ibh, int flags)
+{
+	ino_t ino = inode->i_ino;
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct inode *ifile = ii->i_root->ifile;
+	struct nilfs_inode *raw_inode;
+
+	raw_inode = nilfs_ifile_map_inode(ifile, ino, ibh);
+
+	if (test_and_clear_bit(NILFS_I_NEW, &ii->i_state))
+		memset(raw_inode, 0, NILFS_MDT(ifile)->mi_entry_size);
+	if (flags & I_DIRTY_DATASYNC)
+		set_bit(NILFS_I_INODE_SYNC, &ii->i_state);
+
+	nilfs_write_inode_common(inode, raw_inode, 0);
+		/*
+		 * XXX: call with has_bmap = 0 is a workaround to avoid
+		 * deadlock of bmap.  This delays update of i_bmap to just
+		 * before writing.
+		 */
+
+	nilfs_ifile_unmap_inode(ifile, ino, ibh);
+}
+
+#define NILFS_MAX_TRUNCATE_BLOCKS	16384  /* 64MB for 4KB block */
+
+static void nilfs_truncate_bmap(struct nilfs_inode_info *ii,
+				unsigned long from)
+{
+	__u64 b;
+	int ret;
+
+	if (!test_bit(NILFS_I_BMAP, &ii->i_state))
+		return;
+repeat:
+	ret = nilfs_bmap_last_key(ii->i_bmap, &b);
+	if (ret == -ENOENT)
+		return;
+	else if (ret < 0)
+		goto failed;
+
+	if (b < from)
+		return;
+
+	b -= min_t(__u64, NILFS_MAX_TRUNCATE_BLOCKS, b - from);
+	ret = nilfs_bmap_truncate(ii->i_bmap, b);
+	nilfs_relax_pressure_in_lock(ii->vfs_inode.i_sb);
+	if (!ret || (ret == -ENOMEM &&
+		     nilfs_bmap_truncate(ii->i_bmap, b) == 0))
+		goto repeat;
+
+failed:
+	nilfs_warn(ii->vfs_inode.i_sb, "error %d truncating bmap (ino=%lu)",
+		   ret, ii->vfs_inode.i_ino);
+}
+
+void nilfs_truncate(struct inode *inode)
+{
+	unsigned long blkoff;
+	unsigned int blocksize;
+	struct nilfs_transaction_info ti;
+	struct super_block *sb = inode->i_sb;
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+
+	if (!test_bit(NILFS_I_BMAP, &ii->i_state))
+		return;
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+		return;
+
+	blocksize = sb->s_blocksize;
+	blkoff = (inode->i_size + blocksize - 1) >> sb->s_blocksize_bits;
+	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
+
+	block_truncate_page(inode->i_mapping, inode->i_size, nilfs_get_block);
+
+	nilfs_truncate_bmap(ii, blkoff);
+
+	inode->i_mtime = inode_set_ctime_current(inode);
+	if (IS_SYNC(inode))
+		nilfs_set_transaction_flag(NILFS_TI_SYNC);
+
+	nilfs_mark_inode_dirty(inode);
+	nilfs_set_file_dirty(inode, 0);
+	nilfs_transaction_commit(sb);
+	/*
+	 * May construct a logical segment and may fail in sync mode.
+	 * But truncate has no return value.
+	 */
+}
+
+static void nilfs_clear_inode(struct inode *inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+
+	/*
+	 * Free resources allocated in nilfs_read_inode(), here.
+	 */
+	BUG_ON(!list_empty(&ii->i_dirty));
+	brelse(ii->i_bh);
+	ii->i_bh = NULL;
+
+	if (nilfs_is_metadata_file_inode(inode))
+		nilfs_mdt_clear(inode);
+
+	if (test_bit(NILFS_I_BMAP, &ii->i_state))
+		nilfs_bmap_clear(ii->i_bmap);
+
+	if (!test_bit(NILFS_I_BTNC, &ii->i_state))
+		nilfs_detach_btree_node_cache(inode);
+
+	if (ii->i_root && inode->i_ino == NILFS_ROOT_INO)
+		nilfs_put_root(ii->i_root);
+}
+
+void nilfs_evict_inode(struct inode *inode)
+{
+	struct nilfs_transaction_info ti;
+	struct super_block *sb = inode->i_sb;
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct the_nilfs *nilfs;
+	int ret;
+
+	if (inode->i_nlink || !ii->i_root || unlikely(is_bad_inode(inode))) {
+		truncate_inode_pages_final(&inode->i_data);
+		clear_inode(inode);
+		nilfs_clear_inode(inode);
+		return;
+	}
+	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
+
+	truncate_inode_pages_final(&inode->i_data);
+
+	nilfs = sb->s_fs_info;
+	if (unlikely(sb_rdonly(sb) || !nilfs->ns_writer)) {
+		/*
+		 * If this inode is about to be disposed after the file system
+		 * has been degraded to read-only due to file system corruption
+		 * or after the writer has been detached, do not make any
+		 * changes that cause writes, just clear it.
+		 * Do this check after read-locking ns_segctor_sem by
+		 * nilfs_transaction_begin() in order to avoid a race with
+		 * the writer detach operation.
+		 */
+		clear_inode(inode);
+		nilfs_clear_inode(inode);
+		nilfs_transaction_abort(sb);
+		return;
+	}
+
+	/* TODO: some of the following operations may fail.  */
+	nilfs_truncate_bmap(ii, 0);
+	nilfs_mark_inode_dirty(inode);
+	clear_inode(inode);
+
+	ret = nilfs_ifile_delete_inode(ii->i_root->ifile, inode->i_ino);
+	if (!ret)
+		atomic64_dec(&ii->i_root->inodes_count);
+
+	nilfs_clear_inode(inode);
+
+	if (IS_SYNC(inode))
+		nilfs_set_transaction_flag(NILFS_TI_SYNC);
+	nilfs_transaction_commit(sb);
+	/*
+	 * May construct a logical segment and may fail in sync mode.
+	 * But delete_inode has no return value.
+	 */
+}
+
+int nilfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		  struct iattr *iattr)
+{
+	struct nilfs_transaction_info ti;
+	struct inode *inode = d_inode(dentry);
+	struct super_block *sb = inode->i_sb;
+	int err;
+
+	err = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
+	if (err)
+		return err;
+
+	err = nilfs_transaction_begin(sb, &ti, 0);
+	if (unlikely(err))
+		return err;
+
+	if ((iattr->ia_valid & ATTR_SIZE) &&
+	    iattr->ia_size != i_size_read(inode)) {
+		inode_dio_wait(inode);
+		truncate_setsize(inode, iattr->ia_size);
+		nilfs_truncate(inode);
+	}
+
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
+	mark_inode_dirty(inode);
+
+	if (iattr->ia_valid & ATTR_MODE) {
+		err = nilfs_acl_chmod(inode);
+		if (unlikely(err))
+			goto out_err;
+	}
+
+	return nilfs_transaction_commit(sb);
+
+out_err:
+	nilfs_transaction_abort(sb);
+	return err;
+}
+
+int nilfs_permission(struct mnt_idmap *idmap, struct inode *inode,
+		     int mask)
+{
+	struct nilfs_root *root = NILFS_I(inode)->i_root;
+
+	if ((mask & MAY_WRITE) && root &&
+	    root->cno != NILFS_CPTREE_CURRENT_CNO)
+		return -EROFS; /* snapshot is not writable */
+
+	return generic_permission(&nop_mnt_idmap, inode, mask);
+}
+
+int nilfs_load_inode_block(struct inode *inode, struct buffer_head **pbh)
+{
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	int err;
+
+	spin_lock(&nilfs->ns_inode_lock);
+	if (ii->i_bh == NULL || unlikely(!buffer_uptodate(ii->i_bh))) {
+		spin_unlock(&nilfs->ns_inode_lock);
+		err = nilfs_ifile_get_inode_block(ii->i_root->ifile,
+						  inode->i_ino, pbh);
+		if (unlikely(err))
+			return err;
+		spin_lock(&nilfs->ns_inode_lock);
+		if (ii->i_bh == NULL)
+			ii->i_bh = *pbh;
+		else if (unlikely(!buffer_uptodate(ii->i_bh))) {
+			__brelse(ii->i_bh);
+			ii->i_bh = *pbh;
+		} else {
+			brelse(*pbh);
+			*pbh = ii->i_bh;
+		}
+	} else
+		*pbh = ii->i_bh;
+
+	get_bh(*pbh);
+	spin_unlock(&nilfs->ns_inode_lock);
+	return 0;
+}
+
+int nilfs_inode_dirty(struct inode *inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+	int ret = 0;
+
+	if (!list_empty(&ii->i_dirty)) {
+		spin_lock(&nilfs->ns_inode_lock);
+		ret = test_bit(NILFS_I_DIRTY, &ii->i_state) ||
+			test_bit(NILFS_I_BUSY, &ii->i_state);
+		spin_unlock(&nilfs->ns_inode_lock);
+	}
+	return ret;
+}
+
+int nilfs_set_file_dirty(struct inode *inode, unsigned int nr_dirty)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+
+	atomic_add(nr_dirty, &nilfs->ns_ndirtyblks);
+
+	if (test_and_set_bit(NILFS_I_DIRTY, &ii->i_state))
+		return 0;
+
+	spin_lock(&nilfs->ns_inode_lock);
+	if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
+	    !test_bit(NILFS_I_BUSY, &ii->i_state)) {
+		/*
+		 * Because this routine may race with nilfs_dispose_list(),
+		 * we have to check NILFS_I_QUEUED here, too.
+		 */
+		if (list_empty(&ii->i_dirty) && igrab(inode) == NULL) {
+			/*
+			 * This will happen when somebody is freeing
+			 * this inode.
+			 */
+			nilfs_warn(inode->i_sb,
+				   "cannot set file dirty (ino=%lu): the file is being freed",
+				   inode->i_ino);
+			spin_unlock(&nilfs->ns_inode_lock);
+			return -EINVAL; /*
+					 * NILFS_I_DIRTY may remain for
+					 * freeing inode.
+					 */
+		}
+		list_move_tail(&ii->i_dirty, &nilfs->ns_dirty_files);
+		set_bit(NILFS_I_QUEUED, &ii->i_state);
+	}
+	spin_unlock(&nilfs->ns_inode_lock);
+	return 0;
+}
+
+int __nilfs_mark_inode_dirty(struct inode *inode, int flags)
+{
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+	struct buffer_head *ibh;
+	int err;
+
+	/*
+	 * Do not dirty inodes after the log writer has been detached
+	 * and its nilfs_root struct has been freed.
+	 */
+	if (unlikely(nilfs_purging(nilfs)))
+		return 0;
+
+	err = nilfs_load_inode_block(inode, &ibh);
+	if (unlikely(err)) {
+		nilfs_warn(inode->i_sb,
+			   "cannot mark inode dirty (ino=%lu): error %d loading inode block",
+			   inode->i_ino, err);
+		return err;
+	}
+	nilfs_update_inode(inode, ibh, flags);
+	mark_buffer_dirty(ibh);
+	nilfs_mdt_mark_dirty(NILFS_I(inode)->i_root->ifile);
+	brelse(ibh);
+	return 0;
+}
+
+/**
+ * nilfs_dirty_inode - reflect changes on given inode to an inode block.
+ * @inode: inode of the file to be registered.
+ * @flags: flags to determine the dirty state of the inode
+ *
+ * nilfs_dirty_inode() loads a inode block containing the specified
+ * @inode and copies data from a nilfs_inode to a corresponding inode
+ * entry in the inode block. This operation is excluded from the segment
+ * construction. This function can be called both as a single operation
+ * and as a part of indivisible file operations.
+ */
+void nilfs_dirty_inode(struct inode *inode, int flags)
+{
+	struct nilfs_transaction_info ti;
+	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
+
+	if (is_bad_inode(inode)) {
+		nilfs_warn(inode->i_sb,
+			   "tried to mark bad_inode dirty. ignored.");
+		dump_stack();
+		return;
+	}
+	if (mdi) {
+		nilfs_mdt_mark_dirty(inode);
+		return;
+	}
+	nilfs_transaction_begin(inode->i_sb, &ti, 0);
+	__nilfs_mark_inode_dirty(inode, flags);
+	nilfs_transaction_commit(inode->i_sb); /* never fails */
+}
+
+int nilfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+		 __u64 start, __u64 len)
+{
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+	__u64 logical = 0, phys = 0, size = 0;
+	__u32 flags = 0;
+	loff_t isize;
+	sector_t blkoff, end_blkoff;
+	sector_t delalloc_blkoff;
+	unsigned long delalloc_blklen;
+	unsigned int blkbits = inode->i_blkbits;
+	int ret, n;
+
+	ret = fiemap_prep(inode, fieinfo, start, &len, 0);
+	if (ret)
+		return ret;
+
+	inode_lock(inode);
+
+	isize = i_size_read(inode);
+
+	blkoff = start >> blkbits;
+	end_blkoff = (start + len - 1) >> blkbits;
+
+	delalloc_blklen = nilfs_find_uncommitted_extent(inode, blkoff,
+							&delalloc_blkoff);
+
+	do {
+		__u64 blkphy;
+		unsigned int maxblocks;
+
+		if (delalloc_blklen && blkoff == delalloc_blkoff) {
+			if (size) {
+				/* End of the current extent */
+				ret = fiemap_fill_next_extent(
+					fieinfo, logical, phys, size, flags);
+				if (ret)
+					break;
+			}
+			if (blkoff > end_blkoff)
+				break;
+
+			flags = FIEMAP_EXTENT_MERGED | FIEMAP_EXTENT_DELALLOC;
+			logical = blkoff << blkbits;
+			phys = 0;
+			size = delalloc_blklen << blkbits;
+
+			blkoff = delalloc_blkoff + delalloc_blklen;
+			delalloc_blklen = nilfs_find_uncommitted_extent(
+				inode, blkoff, &delalloc_blkoff);
+			continue;
+		}
+
+		/*
+		 * Limit the number of blocks that we look up so as
+		 * not to get into the next delayed allocation extent.
+		 */
+		maxblocks = INT_MAX;
+		if (delalloc_blklen)
+			maxblocks = min_t(sector_t, delalloc_blkoff - blkoff,
+					  maxblocks);
+		blkphy = 0;
+
+		down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+		n = nilfs_bmap_lookup_contig(
+			NILFS_I(inode)->i_bmap, blkoff, &blkphy, maxblocks);
+		up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+
+		if (n < 0) {
+			int past_eof;
+
+			if (unlikely(n != -ENOENT))
+				break; /* error */
+
+			/* HOLE */
+			blkoff++;
+			past_eof = ((blkoff << blkbits) >= isize);
+
+			if (size) {
+				/* End of the current extent */
+
+				if (past_eof)
+					flags |= FIEMAP_EXTENT_LAST;
+
+				ret = fiemap_fill_next_extent(
+					fieinfo, logical, phys, size, flags);
+				if (ret)
+					break;
+				size = 0;
+			}
+			if (blkoff > end_blkoff || past_eof)
+				break;
+		} else {
+			if (size) {
+				if (phys && blkphy << blkbits == phys + size) {
+					/* The current extent goes on */
+					size += n << blkbits;
+				} else {
+					/* Terminate the current extent */
+					ret = fiemap_fill_next_extent(
+						fieinfo, logical, phys, size,
+						flags);
+					if (ret || blkoff > end_blkoff)
+						break;
+
+					/* Start another extent */
+					flags = FIEMAP_EXTENT_MERGED;
+					logical = blkoff << blkbits;
+					phys = blkphy << blkbits;
+					size = n << blkbits;
+				}
+			} else {
+				/* Start a new extent */
+				flags = FIEMAP_EXTENT_MERGED;
+				logical = blkoff << blkbits;
+				phys = blkphy << blkbits;
+				size = n << blkbits;
+			}
+			blkoff += n;
+		}
+		cond_resched();
+	} while (true);
+
+	/* If ret is 1 then we just hit the end of the extent array */
+	if (ret == 1)
+		ret = 0;
+
+	inode_unlock(inode);
+	return ret;
+}