Ceph » fs

Inter-MDS messages are now versioned. We should add a check that confirms that no current or new messages sent between MDSs are not versioned. In [1], I've suggested that we do:

Because it's not easily determined if a message passed between MDSs is versioned, I suggest one more change where all MDS-MDS messages inherit from a new message class (like MOSDPeeringOp) which we can then trivially check in MDSRankDispatcher::ms_dispatch:

if (m->get_source().is_mds()) {
ceph_assert(dynamic_cast<MMDSOp*>(m.get()));
}
So any new or missing messages must (at least) inherit from that class before the MDS will even dispatch the message.

[1] https://github.com/ceph/ceph/pull/20160#pullrequestreview-268596680