[PATCH] btrfs: tree-log: Check btrfs_lookup_data_extent return value

[PATCH] btrfs: tree-log: Check btrfs_lookup_data_extent return value

[Marcos Paulo de Souza]

Function btrfs_lookup_data_extent calls btrfs_search_slot to verify if
the EXTENT_ITEM exists in the extent tree. btrfs_search_slot can return
values bellow zero if an error happened.

Function replay_one_extent currently check if the search found something
(0 returned) and increments the reference, and if not, it seems to evaluate as
'not found'.

Fix the condition by checking if the value was bellow zero and return early.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
---

 Found while inspecting some btrfs_search_slot call sites.

 fs/btrfs/tree-log.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 567adc3de11a..867ea0be0665 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -753,7 +753,9 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 			 */
 			ret = btrfs_lookup_data_extent(fs_info, ins.objectid,
 						ins.offset);
-			if (ret == 0) {
+			if (ret < 0) {
+				goto out;
+			} else if (ret == 0) {
 				btrfs_init_generic_ref(&ref,
 						BTRFS_ADD_DELAYED_REF,
 						ins.objectid, ins.offset, 0);
-- 
2.26.2

Re: [PATCH] btrfs: tree-log: Check btrfs_lookup_data_extent return value

[Filipe Manana]

On Mon, Aug 2, 2021 at 1:35 PM Marcos Paulo de Souza <mpdesouza@suse.com> wrote:
>
> Function btrfs_lookup_data_extent calls btrfs_search_slot to verify if
> the EXTENT_ITEM exists in the extent tree. btrfs_search_slot can return
> values bellow zero if an error happened.
>
> Function replay_one_extent currently check if the search found something
> (0 returned) and increments the reference, and if not, it seems to evaluate as
> 'not found'.
>
> Fix the condition by checking if the value was bellow zero and return early.
>
> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>

Reviewed-by: Filipe Manana <fdmanana@suse.com>

That's fine, thanks.

> ---
>
>  Found while inspecting some btrfs_search_slot call sites.
>
>  fs/btrfs/tree-log.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 567adc3de11a..867ea0be0665 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -753,7 +753,9 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
>                          */
>                         ret = btrfs_lookup_data_extent(fs_info, ins.objectid,
>                                                 ins.offset);
> -                       if (ret == 0) {
> +                       if (ret < 0) {
> +                               goto out;
> +                       } else if (ret == 0) {
>                                 btrfs_init_generic_ref(&ref,
>                                                 BTRFS_ADD_DELAYED_REF,
>                                                 ins.objectid, ins.offset, 0);
> --
> 2.26.2
>


-- 
Filipe David Manana,

“Whether you think you can, or you think you can't — you're right.”

Re: [PATCH] btrfs: tree-log: Check btrfs_lookup_data_extent return value

[David Sterba]

On Mon, Aug 02, 2021 at 09:34:00AM -0300, Marcos Paulo de Souza wrote:
> Function btrfs_lookup_data_extent calls btrfs_search_slot to verify if
> the EXTENT_ITEM exists in the extent tree. btrfs_search_slot can return
> values bellow zero if an error happened.
> 
> Function replay_one_extent currently check if the search found something
> (0 returned) and increments the reference, and if not, it seems to evaluate as
> 'not found'.
> 
> Fix the condition by checking if the value was bellow zero and return early.
> 
> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>

Added to misc-next, thanks.