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References: <20180320173632.25480-1-kwolf@redhat.com>
	<20180320173632.25480-10-kwolf@redhat.com>
From: Eric Blake <eblake@redhat.com>
Message-ID: <9f3f550c-2941-bf65-4a5f-1b3933c68352@redhat.com>
Date: Tue, 20 Mar 2018 13:43:33 -0500
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Subject: Re: [Qemu-devel] [PATCH for-2.12 09/12] vhdx: Require power-of-two
 block size on create
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To: Kevin Wolf <kwolf@redhat.com>, qemu-block@nongnu.org
Cc: mreitz@redhat.com, den@openvz.org, jcody@redhat.com, berrange@redhat.com, qemu-devel@nongnu.org

On 03/20/2018 12:36 PM, 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.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   block/vhdx.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 

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

> 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);
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org