I am running a Xubuntu 14.04 guest in VirtualBox (on a Win 7 host).
The virtual disk ("Dynamically allocated") filled up, so I followed this answer using VBoxManage modifyhd to increase its size, which was easy.
Next time I started the Xubuntu guest however didn't show any free space on the drive, also gparted still shows the old disk size.
What do I have to do to make the guest recognise that the size has changed so it can make use of the added space?