diff mbox series

qcow2: Return the original error code in qcow2_co_pwrite_zeroes()

Message ID 20200909123739.719-1-berto@igalia.com (mailing list archive)
State New, archived
Headers show
Series qcow2: Return the original error code in qcow2_co_pwrite_zeroes() | expand

Commit Message

Alberto Garcia Sept. 9, 2020, 12:37 p.m. UTC
This function checks the current status of a (sub)cluster in order to
see if an unaligned 'write zeroes' request can be done efficiently by
simply updating the L2 metadata and without having to write actual
zeroes to disk.

If the situation does not allow using the fast path then the function
returns -ENOTSUP and the caller falls back to writing zeroes.

If can happen however that the aforementioned check returns an actual
error code so in this case we should pass it to the caller.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block/qcow2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Eric Blake Sept. 9, 2020, 4:31 p.m. UTC | #1
On 9/9/20 7:37 AM, Alberto Garcia wrote:
> This function checks the current status of a (sub)cluster in order to
> see if an unaligned 'write zeroes' request can be done efficiently by
> simply updating the L2 metadata and without having to write actual
> zeroes to disk.
> 
> If the situation does not allow using the fast path then the function
> returns -ENOTSUP and the caller falls back to writing zeroes.
> 
> If can happen however that the aforementioned check returns an actual
> error code so in this case we should pass it to the caller.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>   block/qcow2.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Eric Blake <eblake@redhat.com>
Philippe Mathieu-Daudé Sept. 9, 2020, 4:41 p.m. UTC | #2
On 9/9/20 2:37 PM, Alberto Garcia wrote:
> This function checks the current status of a (sub)cluster in order to
> see if an unaligned 'write zeroes' request can be done efficiently by
> simply updating the L2 metadata and without having to write actual
> zeroes to disk.
> 
> If the situation does not allow using the fast path then the function
> returns -ENOTSUP and the caller falls back to writing zeroes.
> 
> If can happen however that the aforementioned check returns an actual
> error code so in this case we should pass it to the caller.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block/qcow2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index da56b1a4df..ca46cbd795 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -3916,7 +3916,7 @@ static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
>               type != QCOW2_SUBCLUSTER_ZERO_PLAIN &&
>               type != QCOW2_SUBCLUSTER_ZERO_ALLOC)) {
>              qemu_co_mutex_unlock(&s->lock);
> -            return -ENOTSUP;
> +            return ret < 0 ? ret : -ENOTSUP;
>          }
>      } else {
>          qemu_co_mutex_lock(&s->lock);
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Kevin Wolf Sept. 10, 2020, 12:12 p.m. UTC | #3
Am 09.09.2020 um 14:37 hat Alberto Garcia geschrieben:
> This function checks the current status of a (sub)cluster in order to
> see if an unaligned 'write zeroes' request can be done efficiently by
> simply updating the L2 metadata and without having to write actual
> zeroes to disk.
> 
> If the situation does not allow using the fast path then the function
> returns -ENOTSUP and the caller falls back to writing zeroes.
> 
> If can happen however that the aforementioned check returns an actual
> error code so in this case we should pass it to the caller.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>

Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Max Reitz Sept. 11, 2020, 9 a.m. UTC | #4
On 09.09.20 14:37, Alberto Garcia wrote:
> This function checks the current status of a (sub)cluster in order to
> see if an unaligned 'write zeroes' request can be done efficiently by
> simply updating the L2 metadata and without having to write actual
> zeroes to disk.
> 
> If the situation does not allow using the fast path then the function
> returns -ENOTSUP and the caller falls back to writing zeroes.
> 
> If can happen however that the aforementioned check returns an actual
> error code so in this case we should pass it to the caller.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block/qcow2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Thanks, applied to my block branch:

https://git.xanclic.moe/XanClic/qemu/commits/branch/block
diff mbox series

Patch

diff --git a/block/qcow2.c b/block/qcow2.c
index da56b1a4df..ca46cbd795 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3916,7 +3916,7 @@  static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
              type != QCOW2_SUBCLUSTER_ZERO_PLAIN &&
              type != QCOW2_SUBCLUSTER_ZERO_ALLOC)) {
             qemu_co_mutex_unlock(&s->lock);
-            return -ENOTSUP;
+            return ret < 0 ? ret : -ENOTSUP;
         }
     } else {
         qemu_co_mutex_lock(&s->lock);