[PATCH] qcow2: Return the original error code in qcow2_co_pwrite_zeroes()

[PATCH] qcow2: Return the original error code in qcow2_co_pwrite_zeroes()

[Alberto Garcia]

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);
-- 
2.20.1

Re: [PATCH] qcow2: Return the original error code in qcow2_co_pwrite_zeroes()

[Eric Blake]

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>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

Re: [PATCH] qcow2: Return the original error code in qcow2_co_pwrite_zeroes()

[Philippe Mathieu-Daudé]

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>

Re: [PATCH] qcow2: Return the original error code in qcow2_co_pwrite_zeroes()

[Kevin Wolf]

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>

Re: [PATCH] qcow2: Return the original error code in qcow2_co_pwrite_zeroes()

[Max Reitz]

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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


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