I am able to create Cinder volumes based on my loopback device just fine, though I am unable to attach the volume to any instances.

# nova volume-attach 95aea9f5-4542-4e2b-952f-c95f0354dcb8 55fc1b54-fa83-4143-8371-00fbe984bced
+----------+--------------------------------------+
| Property | Value                                |
+----------+--------------------------------------+
| device   | /dev/vdb                             |
| id       | 55fc1b54-fa83-4143-8371-00fbe984bced |
| serverId | 95aea9f5-4542-4e2b-952f-c95f0354dcb8 |
| volumeId | 55fc1b54-fa83-4143-8371-00fbe984bced |
+----------+--------------------------------------+

I've narrowed it down to the following error log in the cinder api.log on my cinder controller:

IOError: [Errno 13] Permission denied: '/var/lock/cinder/cinder-lioadm'

I've double checked the cinder config on both the storage controller and node (seperate hosts).

Any ideas would be appreciated.