This is a note to let you know that I've just added the patch titled
btrfs: abort transaction at update_ref_for_cow() when ref count is zero
to the 6.4-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-abort-transaction-at-update_ref_for_cow-when-r.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c753b330c41c8f311cd03dc8b18fcad6f947bf9e
Author: Filipe Manana <fdmanana@xxxxxxxx>
Date: Thu Jun 8 11:27:45 2023 +0100
btrfs: abort transaction at update_ref_for_cow() when ref count is zero
[ Upstream commit eced687e224eb3cc5a501cf53ad9291337c8dbc5 ]
At update_ref_for_cow() we are calling btrfs_handle_fs_error() if we find
that the extent buffer has an unexpected ref count of zero, however we can
simply use btrfs_abort_transaction(), which achieves the same purposes: to
turn the fs to error state, abort the current transaction and turn the fs
to RO mode as well. Besides that, btrfs_abort_transaction() also prints a
stack trace which makes it more useful.
Also, as this is a very unexpected situation, indicating a serious
corruption/inconsistency, tag the if branch as 'unlikely', set the error
code to -EUCLEAN instead of -EROFS, and log an explicit message.
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 4912d624ca3d3..886e661a218fc 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -417,9 +417,13 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
&refs, &flags);
if (ret)
return ret;
- if (refs == 0) {
- ret = -EROFS;
- btrfs_handle_fs_error(fs_info, ret, NULL);
+ if (unlikely(refs == 0)) {
+ btrfs_crit(fs_info,
+ "found 0 references for tree block at bytenr %llu level %d root %llu",
+ buf->start, btrfs_header_level(buf),
+ btrfs_root_id(root));
+ ret = -EUCLEAN;
+ btrfs_abort_transaction(trans, ret);
return ret;
}
} else {
