[Qemu-devel] [PATCH for-2.1] block: Fix bdrv_is_allocated() return value

[Qemu-devel] [PATCH for-2.1] block: Fix bdrv_is_allocated() return value

[Kevin Wolf]

bdrv_is_allocated() should return either 0 or 1 in successful cases.
We're lucky that currently, the callers that rely on this (e.g. because
they check for ret == 1) don't seem to break badly. They just might skip
some optimisation or in the case of qemu-io 'map' print separate lines
where a single line would suffice. In theory, a wrong allocation status
could lead to image corruption with certain operations, so let's fix
this quickly.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block.c b/block.c
index f80e2b2..e2e9cbb 100644
--- a/block.c
+++ b/block.c
@@ -4039,7 +4039,7 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
     if (ret < 0) {
         return ret;
     }
-    return (ret & BDRV_BLOCK_ALLOCATED);
+    return !!(ret & BDRV_BLOCK_ALLOCATED);
 }
 
 /*
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH for-2.1] block: Fix bdrv_is_allocated() return value

[Eric Blake]

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On 07/07/2014 09:37 AM, Kevin Wolf wrote:
> bdrv_is_allocated() should return either 0 or 1 in successful cases.
> We're lucky that currently, the callers that rely on this (e.g. because
> they check for ret == 1) don't seem to break badly. They just might skip
> some optimisation or in the case of qemu-io 'map' print separate lines
> where a single line would suffice. In theory, a wrong allocation status
> could lead to image corruption with certain operations, so let's fix
> this quickly.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block.c b/block.c
> index f80e2b2..e2e9cbb 100644
> --- a/block.c
> +++ b/block.c
> @@ -4039,7 +4039,7 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
>      if (ret < 0) {
>          return ret;
>      }
> -    return (ret & BDRV_BLOCK_ALLOCATED);
> +    return !!(ret & BDRV_BLOCK_ALLOCATED);

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH for-2.1] block: Fix bdrv_is_allocated() return value

[Kevin Wolf]

Am 07.07.2014 um 17:37 hat Kevin Wolf geschrieben:
> bdrv_is_allocated() should return either 0 or 1 in successful cases.
> We're lucky that currently, the callers that rely on this (e.g. because
> they check for ret == 1) don't seem to break badly. They just might skip
> some optimisation or in the case of qemu-io 'map' print separate lines
> where a single line would suffice. In theory, a wrong allocation status
> could lead to image corruption with certain operations, so let's fix
> this quickly.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Applied to the block branch.

Kevin