This is a note to let you know that I've just added the patch titled btrfs: do not warn if we can't find the reloc root when looking up backref to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: btrfs-do-not-warn-if-we-can-t-find-the-reloc-root-when-looking-up-backref.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From f78743fbdae1bb31bc9c9233c3590a5048782381 Mon Sep 17 00:00:00 2001 From: Josef Bacik <josef@xxxxxxxxxxxxxx> Date: Thu, 14 Jan 2021 14:02:44 -0500 Subject: btrfs: do not warn if we can't find the reloc root when looking up backref From: Josef Bacik <josef@xxxxxxxxxxxxxx> commit f78743fbdae1bb31bc9c9233c3590a5048782381 upstream. The backref code is looking for a reloc_root that corresponds to the given fs root. However any number of things could have gone wrong while initializing that reloc_root, like ENOMEM while trying to allocate the root itself, or EIO while trying to write the root item. This would result in no corresponding reloc_root being in the reloc root cache, and thus would return NULL when we do the find_reloc_root() call. Because of this we do not want to WARN_ON(). This presumably was meant to catch developer errors, cases where we messed up adding the reloc root. However we can easily hit this case with error injection, and thus should not do a WARN_ON(). CC: stable@xxxxxxxxxxxxxxx # 5.10+ Reported-by: Zygo Blaxell <ce3g8jdj@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/backref.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -2624,7 +2624,7 @@ static int handle_direct_tree_backref(st /* Only reloc backref cache cares about a specific root */ if (cache->is_reloc) { root = find_reloc_root(cache->fs_info, cur->bytenr); - if (WARN_ON(!root)) + if (!root) return -ENOENT; cur->root = root; } else { Patches currently in stable-queue which might be from josef@xxxxxxxxxxxxxx are queue-5.10/btrfs-abort-the-transaction-if-we-fail-to-inc-ref-in-btrfs_copy_root.patch queue-5.10/btrfs-handle-space_info-total_bytes_pinned-inside-the-delayed-ref-itself.patch queue-5.10/btrfs-splice-remaining-dirty_bg-s-onto-the-transaction-dirty-bg-list.patch queue-5.10/btrfs-do-not-warn-if-we-can-t-find-the-reloc-root-when-looking-up-backref.patch queue-5.10/btrfs-fix-reloc-root-leak-with-0-ref-reloc-roots-on-recovery.patch queue-5.10/btrfs-do-not-cleanup-upper-nodes-in-btrfs_backref_cleanup_node.patch queue-5.10/btrfs-account-for-new-extents-being-deleted-in-total_bytes_pinned.patch queue-5.10/proc-use-kvzalloc-for-our-kernel-buffer.patch queue-5.10/btrfs-add-asserts-for-deleting-backref-cache-nodes.patch