[libvirt-users] snapshot-create-as for a single disk not all disks

Hi everyone! Is there any way to create snaphot for a single disk of a virtual machine. As I konw, "virsh snapshot-create-as domain_name snapshot_name --disk-only" traverses all block devices to create snapshot. However I don't want to create snapshot except for root partition. The version of qemu and libvirt I used is as follows: qemu-1.4.2 and libvrit-0.10.2 I meet an error when I delete the snapshot which is created by "snapshot-create-as" command. whether or not qemu(1.4.2) and libvirt(0.10.2) don't support the function currently. Look forward to your help!