$tools/bin/nbmakefs -t ffs -s 1g $name.ffs tree/

        bytes=`ls -l $name.ffs | awk '{print $5}'`
        (( sectors = bytes / 512 ))

        # 10GB is 19531250 x 512 byte sectors
        (( toadd = 19531250 - sectors ))

        echo extending the vdisk to 10GB
        dd if=/dev/zero bs=512 count=$toadd >> $name.ffs && echo done
        ls -lhF $name.ffs
        du -sh $name.ffs
        echo

        echo -n digging holes...
        fallocate --dig-holes $name.ffs && echo done
        ls -lhF $name.ffs
        du -sh $name.ffs
        echo