I think there's a hole in the volume lifecycle. I've been noticing
volumes lingering that should have been cleaned up, and it seems to be
a bug in the state machine for the volumes:
s_fsm.addTransition(Destroy, Event.ExpungingRequested, Expunging);
s_fsm.addTransition(Expunging, Event.ExpungingRequested, Expunging);
s_fsm.addTransition(Expunging, Event.OperationSucceeded, Expunged);
s_fsm.addTransition(Expunging, Event.OperationFailed, Expunging);
If a volume is in Destroy state, it goes to Expunging when the delete
operation is requested. If the delete fails, it remains in expunging.
The storage garbage collector will never try to clean up that volume
again, since it only lists volumes in 'Destroy' and attempts those.
You can only get to Expunging from Destroy, it makes sense to change
that last line to revert the volume state back to Destroy if the
expunge operation failed, so that it will try again next time.
