#! /bin/sh
renice 20 -p $$
guestfish=true
if [ "$1" = "-n" ];then
	guestfish=false
	shift
fi
for file in "$@";do
	if [ "$file" = "${file%.qcow2}" ];then
		echo >&2 "Invalid: <$file>"
		exit 1
	fi
done
for file in "$@";do
	ls -l "$file"
	du -sh "$file"
	set -xe
	mv -i "$file" "$file"-src
	rm -f "$file"-dest
	if $guestfish;then
		test "$(guestfish -n -a "$file"-src run : list-devices : list-partitions|tr '\n' ' ')" = "/dev/vda /dev/vda1 "
		guestfish -n -a "$file"-src run : zerofree /dev/vda1
	fi
	time qemu-img convert -c -f qcow2 "$file"-src -O qcow2 "$file"-dest
	mv -i "$file"-dest "$file"
	rm -f "$file"-src
	set +xe
	ls -l "$file"
	du -sh "$file"
done
echo done