| From | Greg Kroah-Hartman <> | Subject | [ 072/120] ext4: fix fdatasync() for files with only i_size changes | Date | Thu, 11 Oct 2012 10:00:24 +0900 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Jan Kara <jack@suse.cz>
commit b71fc079b5d8f42b2a52743c8d2f1d35d655b1c5 upstream.
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.
Reported-by: Kristian Nielsen <knielsen@knielsen-hq.org> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ext4/inode.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3892,6 +3892,7 @@ static int ext4_do_update_inode(handle_t struct ext4_inode_info *ei = EXT4_I(inode); struct buffer_head *bh = iloc->bh; int err = 0, rc, block; + int need_datasync = 0; /* For fields not not tracking in the in-memory inode, * initialise them to zero for new inodes. */ @@ -3940,7 +3941,10 @@ static int ext4_do_update_inode(handle_t 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); - ext4_isize_set(raw_inode, ei->i_disksize); + 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, @@ -3991,7 +3995,7 @@ static int ext4_do_update_inode(handle_t 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);
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