Re: [Qemu-devel] Creating snapshots with specific runtime options

[Stefan Hajnoczi <stefanha@redhat.com>]

On Tue, Aug 25, 2015 at 04:57:53PM +0300, Alberto Garcia wrote:
> As far as I can see there's no way to create a snapshot and either
> 
>   a) inherit the runtime options from the original image
>   b) specify a new set of options
> 
> This comment in external_snapshot_prepare() before calling bdrv_open()
> suggests that the problem is known but the discussion was postponed.
> 
>     /* TODO Inherit bs->options or only take explicit options with an
>      * extended QMP command? */
> 
> I would like to retake this and make it possible. I discussed it
> briefly with Stefan on IRC and he said that Kevin might have some
> ideas.
> 
> In principle extending the QMP command sounds as simple as adding
> 'options': 'BlockdevOptions' to 'blockdev-snapshot-sync', but it's
> surely more complicated than that :) Is the 'BlockdevOptions' API even
> stable?

Some block drivers don't have BlockdevOptions support yet.

I think that doesn't prevent us from passing BlockdevOptions to snapshot
creation though.