Re: [PATCH for-5.0] qcow2: Check request size in qcow2_co_pwritev_compressed_part()

[Eric Blake]

On 4/3/20 11:57 AM, Alberto Garcia wrote:
> When issuing a compressed write request the number of bytes must be a
> multiple of the cluster size.
>
> With the current code such requests are allowed and we hit an
> assertion:
>
>     $ qemu-img create -f qcow2 img.qcow2 1M
>     $ qemu-io -c 'write -c 0 32k' img.qcow2
>
>     qemu-io: block/qcow2.c:4257: qcow2_co_pwritev_compressed_task:
>     Assertion `bytes == s->cluster_size || (bytes < s->cluster_size &&
>                (offset + bytes == bs->total_sectors << BDRV_SECTOR_BITS))' 
> failed.
>     Aborted
>
> This patch fixes a regression introduced in 0d483dce38
>
> Signed-off-by: Alberto Garcia <address@hidden>
> ---
>   block/qcow2.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Eric Blake <address@hidden>

> diff --git a/block/qcow2.c b/block/qcow2.c
> index 2bb536b014..923ad428f0 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -4345,7 +4345,7 @@ qcow2_co_pwritev_compressed_part(BlockDriverState *bs,
>           return bdrv_co_truncate(bs->file, len, false, PREALLOC_MODE_OFF, 
> NULL);
>       }
>   
> -    if (offset_into_cluster(s, offset)) {
> +    if (offset_into_cluster(s, offset | bytes)) {
>           return -EINVAL;
>       }
>   

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