Comment 3 for bug 1251590

The fix seems sane to me, but I am not familiar with libvirt so I would like to see someone more knowledgeable confirm. It just appears that root disks won't be downloaded for ephemeral backing files, and empty images will be created.

But this fix does seem to just address instances migrated after the patch, is there anyway to retroactively address this in cases that a root disk has already been downloaded?