Re: [Qemu-devel] [PATCH] block/stream: Don't stream unbacked devices

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2013/11/14 3:37, Max Reitz 写道:
> If a block device is unbacked, a streaming blockjob should immediately
> finish instead of beginning to try to stream, then noticing the backing
> file does not contain even the first sector (since it does not exist)
> and then finishing normally.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block/stream.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/block/stream.c b/block/stream.c
> index 694fd42..46bec7d 100644
> --- a/block/stream.c
> +++ b/block/stream.c
> @@ -88,6 +88,11 @@ static void coroutine_fn stream_run(void *opaque)
>       int n = 0;
>       void *buf;
> 
> +    if (!bs->backing_hd) {
> +        block_job_completed(&s->common, 0);
> +        return;
> +    }
> +
>       s->common.len = bdrv_getlength(bs);
>       if (s->common.len < 0) {
>           block_job_completed(&s->common, s->common.len);
> 

Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>