Commit eced687e authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: abort transaction at update_ref_for_cow() when ref count is zero 



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: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 725026ed

fs/btrfs/ctree.c

+7 −3
Original line number Diff line number Diff line
@@ -421,9 +421,13 @@ 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 {