From: Yan, Zheng <zyan@redhat.com>
Date: Mon, 30 Mar 2015 09:35:59 +0000 (+0800)
Subject: mds: fix out-of-order messages
X-Git-Tag: v0.94.10~54^2
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=2332cf22d23fd40ae238b98798e3290094548914;p=ceph.git

mds: fix out-of-order messages

When MDS is no longer laggy, it should process deferred messages
first, then process newly received messages.

Fix: #11258
Signed-off-by: Yan, Zheng <zyan@redhat.com>
(cherry picked from commit ccdeaf87df8b66e09f6b20950b57ac61bf213086)
---

diff --git a/src/mds/MDS.cc b/src/mds/MDS.cc
index 69d6be05a4953..7716e2b4936c8 100644
--- a/src/mds/MDS.cc
+++ b/src/mds/MDS.cc
@@ -2445,7 +2445,7 @@ bool MDS::ms_dispatch(Message *m)
     ret = true;
   } else {
     inc_dispatch_depth();
-    ret = _dispatch(m);
+    ret = _dispatch(m, true);
     dec_dispatch_depth();
   }
   mds_lock.Unlock();
@@ -2674,7 +2674,7 @@ void MDS::_advance_queues()
 
 /* If this function returns true, it has put the message. If it returns false,
  * it has not put the message. */
-bool MDS::_dispatch(Message *m)
+bool MDS::_dispatch(Message *m, bool new_msg)
 {
   if (is_stale_message(m)) {
     m->put();
@@ -2686,6 +2686,9 @@ bool MDS::_dispatch(Message *m)
     if (beacon.is_laggy()) {
       dout(10) << " laggy, deferring " << *m << dendl;
       waiting_for_nolaggy.push_back(m);
+    } else if (new_msg && !waiting_for_nolaggy.empty()) {
+      dout(10) << " there are deferred messages, deferring " << *m << dendl;
+      waiting_for_nolaggy.push_back(m);
     } else {
       if (!handle_deferrable_message(m)) {
 	dout(0) << "unrecognized message " << *m << dendl;
diff --git a/src/mds/MDS.h b/src/mds/MDS.h
index 5da3a8b4697f5..460792c74710a 100644
--- a/src/mds/MDS.h
+++ b/src/mds/MDS.h
@@ -454,7 +454,7 @@ private:
   void dec_dispatch_depth() { --dispatch_depth; }
 
   // messages
-  bool _dispatch(Message *m);
+  bool _dispatch(Message *m, bool new_msg);
 
   protected:
   bool is_stale_message(Message *m);
@@ -488,7 +488,7 @@ public:
   }
   virtual void finish(int r) {
     mds->inc_dispatch_depth();
-    mds->_dispatch(m);
+    mds->_dispatch(m, false);
     mds->dec_dispatch_depth();
   }
 };