Ceph » rbd

Seems 'rbd unmap' calls udevadm settle in krbd.c line 524:

} else {
        /*
    * libudev does not provide the "wait until the queue is empty" 
    * API or the sufficient amount of primitives to build it from.
         */
        string err = run_cmd("udevadm", "settle", "--timeout", "10", "--quiet",
                             NULL);

When I run that command on a Debian Jessie standard installation I get
the following error:

1. udevadm settle --timeout 10 --quiet
   Code should not be reached 'Unknown argument' at ../src/udev/udevadm-settle.c:87, function adm_settle(). Aborting.
   Aborted

There is no '--quiet' flag.