Merge PR ceph#60326 into main

* refs/pull/60326/head:

Reviewed-by: Venky Shankar <[email protected]>
Reviewed-by: Patrick Donnelly <[email protected]>

Author: vshankar

src/mds/MDSDaemon.cc

@@ -923,6 +923,13 @@ void MDSDaemon::suicide()
   // to wait for us to go laggy. Only do this if we're actually in the MDSMap,
   // because otherwise the MDSMonitor will drop our message.
   beacon.set_want_state(*mdsmap, MDSMap::STATE_DNE);
+
+  /* Unlock the mds_lock while waiting for beacon ACK to avoid a
+   * deadlock with the dispatcher thread which may try to acquire
+   * mds_lock, preventing it from receiving the beacon ACK.
+   */
+  mds_lock.unlock();
+
   if (!mdsmap->is_dne_gid(mds_gid_t(monc->get_global_id()))) {
     beacon.send_and_wait(1);
   }
@@ -931,6 +938,8 @@ void MDSDaemon::suicide()
   if (mgrc.is_initialized())
     mgrc.shutdown();
 
+  mds_lock.lock();
+
   if (mds_rank) {
     mds_rank->shutdown();
   } else {