Re: [Qemu-devel] [PATCH] Fix handling of disk-only snapshots

[Anthony Liguori <anthony@codemonkey.ws>]

Kevin Wolf wrote:
> When creating a snapshot with multiple qcow2 disks attached, the current
> behaviour is that qemu creates a disk snapshot on all of them and
> chooses one to write the VM state to.
>
> Despite having the state only in one image, loadvm tries to restore the
> VM state from the middle of nowhere if you run qemu a second time with
> only one of the other images attached. In the lucky case it will fail
> because there simply is no state, but it also can happen that it loads
> the state of a different snapshot (the one this new one is based upon).
>
> The fix is to write a zero VM state size to the images which don't
> contain the state, and check this in loadvm.
>
> I agree that you probably have to provoke such things intentionally to
> get in a state like this with qemu itself. However, with my second patch
> that adds snapshot support to qemu-img it could become a reasonable use
> case to have snapshots with and without VM states on the same image.
>
> Signed-off-by: Kevin Wolf <kwolf@suse.de>
>   

Applied.  Thanks.

Regards,

Anthony Liguori