mgr: drop session with Ceph daemon when not ready

If the mgr is waiting on daemon metadata from the mons, it has no
DaemonState associated with the daemon yet. If we try to process this
MgrOpen, the metadata sent by the daemon (like its config) will not be
recorded.

Fixes: https://tracker.ceph.com/issues/43037
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
(cherry picked from commit 16a1deb)

src/mgr/DaemonServer.cc

@@ -429,12 +429,22 @@ bool DaemonServer::handle_open(MMgrOpen *m)
     dout(20) << "updating existing DaemonState for " << key << dendl;
     daemon = daemon_state.get(key);
   }
-  if (m->service_daemon && !daemon) {
-    dout(4) << "constructing new DaemonState for " << key << dendl;
-    daemon = std::make_shared<DaemonState>(daemon_state.types);
-    daemon->key = key;
-    daemon->service_daemon = true;
-    daemon_state.insert(daemon);
+  if (!daemon) {
+    if (m->service_daemon) {
+      dout(4) << "constructing new DaemonState for " << key << dendl;
+      daemon = std::make_shared<DaemonState>(daemon_state.types);
+      daemon->key = key;
+      daemon->service_daemon = true;
+      daemon_state.insert(daemon);
+    } else {
+      /* A normal Ceph daemon has connected but we are or should be waiting on
+       * metadata for it. Close the session so that it tries to reconnect.
+       */
+      dout(2) << "ignoring open from " << key << " " << con->get_peer_addr()
+              << "; not ready for session (expect reconnect)" << dendl;
+      con->mark_down();
+      return true;
+    }
   }
   if (daemon) {
     if (m->service_daemon) {