How to mount qcow2 images

1. install qemu-utils and enable nbd module

sudo apt-get install qemu-utils
sudo modprobe nbd

2. use any qcow2 image

3. connect the image to the first nbd device

sudo qemu-nbd -c /dev/nbd0 xxx.img

4. Mount the image

sudo mount /dev/nbd0p1 /mnt

5. unmount
sudo umount /mnt

6. disconnect the loopback device
sudo qemu-nbd -d /dev/nbd0