Re: [Qemu-devel] [PATCH for-2.12 09/12] vhdx: Require power-of-two block size on create

[Jeff Cody <jcody@redhat.com>]

On Tue, Mar 20, 2018 at 06:36:29PM +0100, Kevin Wolf wrote:
> Images with a non-power-of-two block size are invalid and cannot be
> opened. Reject such block sizes when creating an image.
> 

Good catch.

Reviewed-by: Jeff Cody <jcody@redhat.com>


> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/vhdx.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/block/vhdx.c b/block/vhdx.c
> index f1b97f4b49..ca211a3196 100644
> --- a/block/vhdx.c
> +++ b/block/vhdx.c
> @@ -1877,6 +1877,10 @@ static int coroutine_fn vhdx_co_create(BlockdevCreateOptions *opts,
>          error_setg_errno(errp, EINVAL, "Block size must be a multiple of 1 MB");
>          return -EINVAL;
>      }
> +    if (!is_power_of_2(block_size)) {
> +        error_setg(errp, "Block size must be a power of two");
> +        return -EINVAL;
> +    }
>      if (block_size > VHDX_BLOCK_SIZE_MAX) {
>          error_setg_errno(errp, EINVAL, "Block size must not exceed %d",
>                           VHDX_BLOCK_SIZE_MAX);
> -- 
> 2.13.6
>