[Libguestfs] virt-resize: ntfsresize: location outside device

I have a 15G qcow2 xp vm with only 1 partition: -rw-------. 1 root root 10514137088 Sep 12 11:10 XP.img I want to resize it to 20G. So I : virsh vol-create-as --format raw windows XP-new-20G.img 20G Vol XP-new-20G.img created -rw-------. 1 root root 21474836480 Sep 12 13:17 XP-new-20G.img But: virt-resize --expand /dev/sda1 XP.img XP-new-20G.img Summary of changes: /dev/sda1: partition will be resized from 14.6G to 20.0G /dev/sda1: content will be expanded using the 'ntfsresize' method part_add: do_part_add: parted: /dev/vdb: Error: The location 41938815s is outside of the device /dev/vdb. at /usr/bin/virt-resize line 1092. Do I use guestfs to do this? BTW, I originally formatted the new vm as qcow2, but virt-resize doesn't recognize it can expand a qcow2 vm: virt-resize --expand /dev/sda1 XP.img XP-new-20G.img virt-resize: XP-new-20G.img: file is too small to be a disk image (262144 bytes) Thanks, sean