If a file in files datastore is required by a vm, don't allow deletion
|Category:||Core & System|
Currently files can be deleted from files datastores without checking whether they are in use by vms. This is fine while the vms are running, as the files have already been copied into the vm, but if a vm is powered off or undeployed then it cannot be started again if a file it was originally created with is missing. Fix for this is to recreate the file in the files datastore with the hash it's expecting; however it would be nice if OpenNebula kept track of which files were used by which vms (similar to images), and opennebula prevented deletion of in-use files.