Merge PR ceph#54030 into main

* refs/pull/54030/head:
	client: always refresh mds feature bits on session open

Reviewed-by: Dhairya Parmar <[email protected]>
Reviewed-by: Kotresh Hiremath Ravishankar <[email protected]>
Reviewed-by: Milind Changire <[email protected]>
Reviewed-by: Patrick Donnelly <[email protected]>

Author: vshankar

src/client/Client.cc

@@ -2384,6 +2384,12 @@ void Client::_closed_mds_session(MetaSession *s, int err, bool rejected)
     mds_sessions.erase(s->mds_num);
 }
 
+static void reinit_mds_features(MetaSession *session,
+				const MConstRef<MClientSession>& m) {
+  session->mds_features = std::move(m->supported_features);
+  session->mds_metric_flags = std::move(m->metric_spec.metric_flags);
+}
+
 void Client::handle_client_session(const MConstRef<MClientSession>& m)
 {
   mds_rank_t from = mds_rank_t(m->get_source().num());
@@ -2402,6 +2408,13 @@ void Client::handle_client_session(const MConstRef<MClientSession>& m)
       if (session->state == MetaSession::STATE_OPEN) {
         ldout(cct, 10) << "mds." << from << " already opened, ignore it"
                        << dendl;
+	// The MDS could send a client_session(open) message even when
+	// the session state is STATE_OPEN. Normally, its fine to
+	// ignore this message, but, if the MDS sent this message just
+	// after it got upgraded, the MDS feature bits could differ
+	// than the one before the upgrade - so, refresh the feature
+	// bits the client holds.
+	reinit_mds_features(session.get(), m);
         return;
       }
       /*
@@ -2411,8 +2424,7 @@ void Client::handle_client_session(const MConstRef<MClientSession>& m)
       if (!session->seq && m->get_seq())
         session->seq = m->get_seq();
 
-      session->mds_features = std::move(m->supported_features);
-      session->mds_metric_flags = std::move(m->metric_spec.metric_flags);
+      reinit_mds_features(session.get(), m);
       cap_auths = std::move(m->cap_auths);
 
       renew_caps(session.get());