linux kvm resize qcow2 Image

Here a very short howto

virsh shutdown kvm11111
qemu-img resize hd.qcow2 +10G
fdisk /dev/vda

Command (m for help): p

Command (m for help): d

Command (m for help): n

Do you want to remove the signature? [Y]es/[N]o: N

Command (m for help): w

boot a rescue image then run

e2fsck -f /dev/vda1

resize2fs /dev/vda1

Have fun!