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Commit b71fc079 authored by Jan Kara's avatar Jan Kara Committed by Theodore Ts'o
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ext4: fix fdatasync() for files with only i_size changes 



Code tracking when transaction needs to be committed on fdatasync(2) forgets
to handle a situation when only inode's i_size is changed. Thus in such
situations fdatasync(2) doesn't force transaction with new i_size to disk
and that can result in wrong i_size after a crash.

Fix the issue by updating inode's i_datasync_tid whenever its size is
updated.

CC: <stable@vger.kernel.org> # >= 2.6.32
Reported-by: default avatarKristian Nielsen <knielsen@knielsen-hq.org>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 6a08f447

fs/ext4/inode.c

+6 −2
Original line number Diff line number Diff line
@@ -4054,6 +4054,7 @@ static int ext4_do_update_inode(handle_t *handle, 
	struct ext4_inode_info *ei = EXT4_I(inode);

	struct buffer_head *bh = iloc->bh;

	int err = 0, rc, block;

	int need_datasync = 0;

	uid_t i_uid;

	gid_t i_gid;
@@ -4104,7 +4105,10 @@ static int ext4_do_update_inode(handle_t *handle, 
		raw_inode->i_file_acl_high =

			cpu_to_le16(ei->i_file_acl >> 32);

	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);

	if (ei->i_disksize != ext4_isize(raw_inode)) {

		ext4_isize_set(raw_inode, ei->i_disksize);

		need_datasync = 1;

	}

	if (ei->i_disksize > 0x7fffffffULL) {

		struct super_block *sb = inode->i_sb;

		if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
@@ -4157,7 +4161,7 @@ static int ext4_do_update_inode(handle_t *handle, 
		err = rc;

	ext4_clear_inode_state(inode, EXT4_STATE_NEW);



	ext4_update_inode_fsync_trans(handle, inode, 0);

	ext4_update_inode_fsync_trans(handle, inode, need_datasync);

out_brelse:

	brelse(bh);

	ext4_std_error(inode->i_sb, err);