Comment 1 for bug 1247998

Couple of additional notes:

This is on a fully updated ubuntu 13.10 install with openstack 1:2013.2-0ubuntu1.

At least on the latest ubuntu, qemu-img supports rbd: paths in qemu-img info and convert. The easiest solution then I think would be to check the image type using qemu-img info and just "return None, False" if it isn't raw.

It could also do the conversion without temp files by passing rbd: paths to qemu-img convert. Somewhat oddly though on my system exporting to a temp file, doing qemu-img convert, and then importing back into rbd is about twice as fast as doing qemu-img convert directly with rbd paths.

The other feature that would be useful would be creating a "shadow" copy of the image that is in raw form so that multiple volumes cloned from the same image could take advantage of COW even for non-raw images (qcow2 seems to be what most things are available for download in).

I might take a crack at implementing this but I'll need to setup a dev version of openstack first :/