Re: [Qemu-devel] [PATCH v9 2/9] blkverify: set supported write/zero flags

[Eric Blake <eblake@redhat.com>]

On 05/08/2018 09:58 AM, Anton Nefedov wrote:
> Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
> Reviewed-by: Alberto Garcia <berto@igalia.com>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> ---
>   block/blkverify.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/block/blkverify.c b/block/blkverify.c
> index 754cc9e..496ae09 100644
> --- a/block/blkverify.c
> +++ b/block/blkverify.c
> @@ -141,6 +141,15 @@ static int blkverify_open(BlockDriverState *bs, QDict *options, int flags,
>           goto fail;
>       }
>   
> +    bs->supported_write_flags = BDRV_REQ_FUA &
> +        bs->file->bs->supported_write_flags &
> +        s->test_file->bs->supported_write_flags;

I wonder if it's worth the effort to support the flags if the main file 
supports them natively but the test_file does not (and just emulate the 
flag on the test file, in that situation).  But for now, I'm fine with 
your choice that both files must support a flag before the blkverify 
layer claims the flag as well.

> +
> +    bs->supported_zero_flags =
> +        (BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) &
> +        bs->file->bs->supported_zero_flags &
> +        s->test_file->bs->supported_zero_flags;
> +
>       ret = 0;
>   fail:
>       qemu_opts_del(opts);
> 

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