diff mbox series

[v2,09/13] btrfs: abort transaction at update_ref_for_cow() when ref count is zero

Message ID 9980464fc9f02392f0dab60c5564495c811ed256.1686219923.git.fdmanana@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: some fixes and updates around handling errors for tree mod log operations | expand

Commit Message

Filipe Manana June 8, 2023, 10:27 a.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

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.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/ctree.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Comments

Qu Wenruo June 8, 2023, 10:52 a.m. UTC | #1 
On 2023/6/8 18:27, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> 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.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>   fs/btrfs/ctree.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index 00eea2925d1d..0449b3d819a9 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -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 {
diff mbox series

Patch

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 00eea2925d1d..0449b3d819a9 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -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 {