Ceph » rbd

See discussion in https://tracker.ceph.com/issues/64735:

There are two separate areas here:
- rollback op handler in the OSD which produces incorrect post-rollback overlap ranges -- visible in "rados listsnaps" output and not specific to RBD. This is what https://github.com/ceph/ceph/pull/55991 is trying to address.
- rbd CLI tool which produces "rbd du" output which is similarly incorrect but most likely (I can't claim this with absolute certainty because I wasn't involved) on purpose. It appears that the OSD bug was basically replicated there to make the numbers line up.

Once the OSD bug is fixed, I'll work on "rbd du". I'm going to clone this ticket to RBD for that purpose.