Feature #2609
Updated by Sage Weil almost 12 years ago
To prevent rename from disrupting clients with images open,
* put header in rbd_head.$id
* put $id in rbd_id.$name
On open, resolve the name -> id by looking at rbd_id.$name, and then open the $id.
Also, make it easy to open an image by id directly; this will be needed by the layering code.