Re: [Qemu-devel] [PATCH v8 06/12] block: Add bdrv_set_backing_hd()

[Stefan Hajnoczi]

On Fri, Dec 13, 2013 at 03:35:14PM +0800, Fam Zheng wrote:
> +void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
> +{
> +    if (bs->backing_hd) {
> +        bdrv_unref(bs->backing_hd);
> +    }
> +
> +    bs->backing_hd = backing_hd;
> +    if (!backing_hd) {
> +        return;
> +    }

Maybe we should also do:
bs->backing_file[0] = '\0';
bs->backing_format[0] = '\0';