In the following scenario, you can end up with a ctdb_freeze_lock child process hanging out and holding the databases locked.

- ctdb starts up and does a ctdb_blocking_freeze() which spawns a freeze lock child
- ctdbd crashes (for whatever reason, in my case it was a bug...)
- the freeze lock child goes into a loop waiting for the parent to exit

The problem is that this is so early that ctdb->ctdbd_pid is not set.  This causes the child to just sit in the wait loop forever (ctdb_freeze.c:216):


	        while (1) {
                        sleep(1);
                        if (kill(ctdb->ctdbd_pid, 0) != 0) {
		                DEBUG(DEBUG_ERR,("Parent died. Exiting lock wait child\n"));

                                _exit(0);
			}
 	        }

The fix is just initialize the ctdbd_pid variable earlier in daemon startup (patch to be attached...)

This issues is rare in that it only happens in a small startup window, but when it does happen, manual intervention is required to kill off the child procs holding the locks.