2d874037f3
This is mostly in preparation for external qcow2 snapshot support. For internal qcow2 snapshots, which currently are the only supported variant, it is not possible to attach the snapshot only. If access to that is required it will need to be handled differently, e.g. via a FUSE/NBD export. Such accesses are currently not done for running VMs via '-drive' either, so there still is feature parity. Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>