Extend the system partition in a Windows virtual machine running within kvm with file-based virtual disk

The post Extend the system partition in a Windows virtual machine running within kvm/lvm is applicable if the virtual disk is on a LVM volume.

If the virtual disk is file-based, these are the required steps:

1. Find out what is the file the virtual machine disk is attached to; assuming disk images are in /var/lib/libvirt/images:

   sudo grep 'var.lib.libvirt.images' /etc/libvirt/qemu/name_of_virtual_machine.xml

   You might see something like:

   <source file='/var/lib/libvirt/images/w7_64_cdev15.dd'/>

2. Shut down the virtual machine
3. Resize the disk image file:

   sudo qemu-img resize /var/lib/libvirt/images/w7_64_cdev15.dd +10G

4. Restart the VM
5. Extend the disk using the guest operating system specific tool; with Windows 7 and later use the extend command from within disk manager (should require no reboot).