4.18-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
commit 0f375eed92b5a407657532637ed9652611a682f5 upstream.
In a scenario like the following:
mkdir /mnt/A # inode 258 mkdir /mnt/B # inode 259 touch /mnt/B/bar # inode 260
sync
mv /mnt/B/bar /mnt/A/bar mv -T /mnt/A /mnt/B fsync /mnt/B/bar
<power fail>
After replaying the log we end up with file bar having 2 hard links, both with the name 'bar' and one in the directory with inode number 258 and the other in the directory with inode number 259. Also, we end up with the directory inode 259 still existing and with the directory inode 258 still named as 'A', instead of 'B'. In this scenario, file 'bar' should only have one hard link, located at directory inode 258, the directory inode 259 should not exist anymore and the name for directory inode 258 should be 'B'.
This incorrect behaviour happens because when attempting to log the old parents of an inode, we skip any parents that no longer exist. Fix this by forcing a full commit if an old parent no longer exists.
A test case for fstests follows soon.
CC: stable@vger.kernel.org # 4.4+ 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 | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-)
--- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -5737,9 +5737,33 @@ static int btrfs_log_all_parents(struct
dir_inode = btrfs_iget(fs_info->sb, &inode_key, root, NULL); - /* If parent inode was deleted, skip it. */ - if (IS_ERR(dir_inode)) - continue; + /* + * If the parent inode was deleted, return an error to + * fallback to a transaction commit. This is to prevent + * getting an inode that was moved from one parent A to + * a parent B, got its former parent A deleted and then + * it got fsync'ed, from existing at both parents after + * a log replay (and the old parent still existing). + * Example: + * + * mkdir /mnt/A + * mkdir /mnt/B + * touch /mnt/B/bar + * sync + * mv /mnt/B/bar /mnt/A/bar + * mv -T /mnt/A /mnt/B + * fsync /mnt/B/bar + * <power fail> + * + * If we ignore the old parent B which got deleted, + * after a log replay we would have file bar linked + * at both parents and the old parent B would still + * exist. + */ + if (IS_ERR(dir_inode)) { + ret = PTR_ERR(dir_inode); + goto out; + }
if (ctx) ctx->log_new_dentries = false;