5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Filipe Manana fdmanana@suse.com
commit 0a32e4f0025a74c70dcab4478e9b29c22f5ecf2f upstream.
If we log a new inode (not persisted in a past transaction) that has 0 links and extents, then log another inode with an higher inode number, we end up with failing to replay the log tree with -EINVAL. The steps for this are:
1) create new file A 2) write some data to file A 3) open an fd on file A 4) unlink file A 5) fsync file A using the previously open fd 6) create file B (has higher inode number than file A) 7) fsync file B 8) power fail before current transaction commits
Now when attempting to mount the fs, the log replay will fail with -ENOENT at replay_one_extent() when attempting to replay the first extent of file A. The failure comes when trying to open the inode for file A in the subvolume tree, since it doesn't exist.
Before commit 5f61b961599a ("btrfs: fix inode lookup error handling during log replay"), the returned error was -EIO instead of -ENOENT, since we converted any errors when attempting to read an inode during log replay to -EIO.
The reason for this is that the log replay procedure fails to ignore the current inode when we are at the stage LOG_WALK_REPLAY_ALL, our current inode has 0 links and last inode we processed in the previous stage has a non 0 link count. In other words, the issue is that at replay_one_extent() we only update wc->ignore_cur_inode if the current replay stage is LOG_WALK_REPLAY_INODES.
Fix this by updating wc->ignore_cur_inode whenever we find an inode item regardless of the current replay stage. This is a simple solution and easy to backport, but later we can do other alternatives like avoid logging extents or inode items other than the inode item for inodes with a link count of 0.
The problem with the wc->ignore_cur_inode logic has been around since commit f2d72f42d5fa ("Btrfs: fix warning when replaying log after fsync of a tmpfile") but it only became frequent to hit since the more recent commit 5e85262e542d ("btrfs: fix fsync of files with no hard links not persisting deletion"), because we stopped skipping inodes with a link count of 0 when logging, while before the problem would only be triggered if trying to replay a log tree created with an older kernel which has a logged inode with 0 links.
A test case for fstests will be submitted soon.
Reported-by: Peter Jung ptr1337@cachyos.org Link: https://lore.kernel.org/linux-btrfs/fce139db-4458-4788-bb97-c29acf6cb1df@cac... Reported-by: burneddi burneddi@protonmail.com Link: https://lore.kernel.org/linux-btrfs/lh4W-Lwc0Mbk-QvBhhQyZxf6VbM3E8VtIvU3fPIQ... Reported-by: Russell Haley yumpusamongus@gmail.com Link: https://lore.kernel.org/linux-btrfs/598ecc75-eb80-41b3-83c2-f2317fbb9864@gma... Fixes: f2d72f42d5fa ("Btrfs: fix warning when replaying log after fsync of a tmpfile") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Boris Burkov boris@bur.io 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 | 48 ++++++++++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 18 deletions(-)
--- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -274,8 +274,7 @@ struct walk_control {
/* * Ignore any items from the inode currently being processed. Needs - * to be set every time we find a BTRFS_INODE_ITEM_KEY and we are in - * the LOG_WALK_REPLAY_INODES stage. + * to be set every time we find a BTRFS_INODE_ITEM_KEY. */ bool ignore_cur_inode;
@@ -2604,23 +2603,30 @@ static int replay_one_buffer(struct btrf
nritems = btrfs_header_nritems(eb); for (i = 0; i < nritems; i++) { - btrfs_item_key_to_cpu(eb, &key, i); + struct btrfs_inode_item *inode_item;
- /* inode keys are done during the first stage */ - if (key.type == BTRFS_INODE_ITEM_KEY && - wc->stage == LOG_WALK_REPLAY_INODES) { - struct btrfs_inode_item *inode_item; - u32 mode; + btrfs_item_key_to_cpu(eb, &key, i);
- inode_item = btrfs_item_ptr(eb, i, - struct btrfs_inode_item); + if (key.type == BTRFS_INODE_ITEM_KEY) { + inode_item = btrfs_item_ptr(eb, i, struct btrfs_inode_item); /* - * If we have a tmpfile (O_TMPFILE) that got fsync'ed - * and never got linked before the fsync, skip it, as - * replaying it is pointless since it would be deleted - * later. We skip logging tmpfiles, but it's always - * possible we are replaying a log created with a kernel - * that used to log tmpfiles. + * An inode with no links is either: + * + * 1) A tmpfile (O_TMPFILE) that got fsync'ed and never + * got linked before the fsync, skip it, as replaying + * it is pointless since it would be deleted later. + * We skip logging tmpfiles, but it's always possible + * we are replaying a log created with a kernel that + * used to log tmpfiles; + * + * 2) A non-tmpfile which got its last link deleted + * while holding an open fd on it and later got + * fsynced through that fd. We always log the + * parent inodes when inode->last_unlink_trans is + * set to the current transaction, so ignore all the + * inode items for this inode. We will delete the + * inode when processing the parent directory with + * replay_dir_deletes(). */ if (btrfs_inode_nlink(eb, inode_item) == 0) { wc->ignore_cur_inode = true; @@ -2628,8 +2634,14 @@ static int replay_one_buffer(struct btrf } else { wc->ignore_cur_inode = false; } - ret = replay_xattr_deletes(wc->trans, root, log, - path, key.objectid); + } + + /* Inode keys are done during the first stage. */ + if (key.type == BTRFS_INODE_ITEM_KEY && + wc->stage == LOG_WALK_REPLAY_INODES) { + u32 mode; + + ret = replay_xattr_deletes(wc->trans, root, log, path, key.objectid); if (ret) break; mode = btrfs_inode_mode(eb, inode_item);