This patch adds two new parameters to the vol-create-as command:
--backing-vol <volume-name-or-key-or-path>
--backing-vol-format <format-of-backing-vol>
virsh # vol-create-as guest_images_lvm snapvol1 5G --backing-vol \
rhel6vm1lun1
Vol snapvol1 created
virsh # vol-create-as image_dir qcow2snap2 5G --format qcow2 \
--backing-vol imagevol1.qcow2 \
--backing-vol-format qcow2
Vol qcow2snap2 created
Additionally, the virsh man page update fixes incorrect snapshot
parameters that were included in my prior bulk volume command patch.