osd: reset session->osdmap if session is not waiting for a map anymore

we should release the osdmap reference once we are done with it,
otherwise we might need to wait very long to update that reference with
a newer osdmap ref. this appears to be an OSDMap leak: it is held by an
quiet OSD::Session forever.

the osdmap is not reset in OSD::session_notify_pg_create(), because its
only caller is wake_pg_waiters(), which will call
dispatch_session_waiting() later. and dispatch_session_waiting() will
check the session->osdmap, and will also reset the osdmap if
session->waiting_for_pg.empty().

Fixes: http://tracker.ceph.com/issues/13990
Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit 82b0af7cedc3071cd83ee53479f834c23c62b7d0)

diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index be52df9f2cb876ce3fd3e2bb190fd0abd960e574..6d01fe8d677311b5ecdbd2508f83e210171c58fe 100644 (file)
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -5782,6 +5782,7 @@ void OSD::dispatch_session_waiting(Session *session, OSDMapRef osdmap)
   } else {
     register_session_waiting_on_map(session);
   }
+  session->maybe_reset_osdmap();
 }
 
 
@@ -5860,6 +5861,7 @@ void OSD::session_notify_pg_cleared(
   assert(session->session_dispatch_lock.is_locked());
   update_waiting_for_pg(session, osdmap);
   session->waiting_for_pg.erase(pgid);
+  session->maybe_reset_osdmap();
   clear_session_waiting_on_pg(session, pgid);
 }
 

diff --git a/src/osd/OSD.h b/src/osd/OSD.h
index 904288e72a69ca8805ef4f932091eadacbab734a..79a0d17aac867ebc62b0ec7cbc5e9da345b841cd 100644 (file)
--- a/src/osd/OSD.h
+++ b/src/osd/OSD.h
@@ -1349,8 +1349,11 @@ public:
       session_dispatch_lock("Session::session_dispatch_lock"), 
       last_sent_epoch(0), received_map_epoch(0)
     {}
-
-
+    void maybe_reset_osdmap() {
+      if (waiting_for_pg.empty()) {
+       osdmap.reset();
+      }
+    }
   };
   void update_waiting_for_pg(Session *session, OSDMapRef osdmap);
   void session_notify_pg_create(Session *session, OSDMapRef osdmap, spg_t pgid);
@@ -1449,6 +1452,7 @@ public:
      */
     session->waiting_on_map.clear();
     session->waiting_for_pg.clear();
+    session->osdmap.reset();
   }
   void register_session_waiting_on_pg(Session *session, spg_t pgid) {
     Mutex::Locker l(session_waiting_lock);