krbd exclusive locking¶

Summary
Exclusive locking allows rbd to ensure that only one client updates an rbd image at time, to preserve metadata consistency.
This is a building block for other rbd features like object map and journalling, and provides a bit of extra safety in case a supposedly dead client reconnects.

Owners
Doug Fuller (Red Hat)

Interested Parties
Josh Durgin (Red Hat)

Current Status
Patches for watch/notify2 and cls_lock primitives that are used to implement this are posted for review.

Detailed Description