Re: [PATCH v2] qcow2: Check request size in qcow2_co_pwritev_compressed_part()

[Vladimir Sementsov-Ogievskiy]

06.04.2020 17:34, Alberto Garcia wrote:
> When issuing a compressed write request the number of bytes must be a
> multiple of the cluster size or reach the end of the last cluster.
>
> 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>

Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>

> ---
>   block/qcow2.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 2bb536b014..587cf51948 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -4349,6 +4349,11 @@ qcow2_co_pwritev_compressed_part(BlockDriverState *bs,
>           return -EINVAL;
>       }
>   
> +    if (offset_into_cluster(s, bytes) &&
> +        (offset + bytes) != (bs->total_sectors << BDRV_SECTOR_BITS)) {
> +        return -EINVAL;
> +    }
> +
>       while (bytes && aio_task_pool_status(aio) == 0) {
>           uint64_t chunk_size = MIN(bytes, s->cluster_size);
>   


--
Best regards,
Vladimir