Comment 5 for bug 1452840

In an attempt to gain insight, I altered Nova's detach_volume method to recheck+retry+log indefinitely, to see how many tries it would take for the detach to eventually succeed.

The answer is, "never, unless another request comes in on a different greenthread to alter the guest's configuration". The test provided script attaches another volume after ten seconds, so after futilely trying to detach the volume (/dev/vdb) for ten seconds, an attach request comes in, succeeds (on /dev/vdc), and unsticks libvirt with regards to detaching the volume, and cleans everything up.