4.16-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
commit 9a8fca62aacc1599fea8e813d01e1955513e4fad upstream.
If a file has xattrs, we fsync it, to ensure we clear the flags BTRFS_INODE_NEEDS_FULL_SYNC and BTRFS_INODE_COPY_EVERYTHING from its inode, the current transaction commits and then we fsync it (without either of those bits being set in its inode), we end up not logging all its xattrs. This results in deleting all xattrs when replying the log after a power failure.
Trivial reproducer
$ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt
$ touch /mnt/foobar $ setfattr -n user.xa -v qwerty /mnt/foobar $ xfs_io -c "fsync" /mnt/foobar
$ sync
$ xfs_io -c "pwrite -S 0xab 0 64K" /mnt/foobar $ xfs_io -c "fsync" /mnt/foobar <power failure>
$ mount /dev/sdb /mnt $ getfattr --absolute-names --dump /mnt/foobar <empty output> $
So fix this by making sure all xattrs are logged if we log a file's inode item and neither the flags BTRFS_INODE_NEEDS_FULL_SYNC nor BTRFS_INODE_COPY_EVERYTHING were set in the inode.
Fixes: 36283bf777d9 ("Btrfs: fix fsync xattr loss in the fast fsync path") Cc: stable@vger.kernel.org # 4.2+ Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/tree-log.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4749,6 +4749,7 @@ static int btrfs_log_inode(struct btrfs_ struct extent_map_tree *em_tree = &inode->extent_tree; u64 logged_isize = 0; bool need_log_inode_item = true; + bool xattrs_logged = false;
path = btrfs_alloc_path(); if (!path) @@ -5050,6 +5051,7 @@ next_key: err = btrfs_log_all_xattrs(trans, root, inode, path, dst_path); if (err) goto out_unlock; + xattrs_logged = true; if (max_key.type >= BTRFS_EXTENT_DATA_KEY && !fast_search) { btrfs_release_path(path); btrfs_release_path(dst_path); @@ -5062,6 +5064,11 @@ log_extents: btrfs_release_path(dst_path); if (need_log_inode_item) { err = log_inode_item(trans, log, dst_path, inode); + if (!err && !xattrs_logged) { + err = btrfs_log_all_xattrs(trans, root, inode, path, + dst_path); + btrfs_release_path(path); + } if (err) goto out_unlock; }