Re: [Qemu-devel] [PATCH v4 3/8] block: don't make snapshots for filters

[Paolo Bonzini]

On 21/09/2016 13:33, Pavel Dovgalyuk wrote:
> This patch disables snapshotting for block driver filters.
> It is needed, because snapshots should be created
> in underlying disk images, not in filters itself.

I don't understand this patch.  Who would take care of doing the
bdrv_snapshot_goto on the underlying image?

Paolo

> Signed-off-by: Pavel Dovgalyuk <address@hidden>
> ---
>  block/snapshot.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/block/snapshot.c b/block/snapshot.c
> index bf5c2ca..8998b8b 100644
> --- a/block/snapshot.c
> +++ b/block/snapshot.c
> @@ -184,6 +184,9 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
>      if (!drv) {
>          return -ENOMEDIUM;
>      }
> +    if (drv->is_filter) {
> +        return 0;
> +    }
>      if (drv->bdrv_snapshot_goto) {
>          return drv->bdrv_snapshot_goto(bs, snapshot_id);
>      }
>