From: Yan, Zheng <zheng.z.yan@intel.com>
Date: Thu, 20 Feb 2014 02:54:45 +0000 (+0800)
Subject: mds: fix stack overflow caused by nested dispatch
X-Git-Tag: v0.79~111^2~17
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=bc3325b37be49f1b7a30aa85645bc1d13fc3ed15;p=ceph.git

mds: fix stack overflow caused by nested dispatch

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
---

diff --git a/src/mds/MDS.cc b/src/mds/MDS.cc
index c62b75fc190..60b28d4a932 100644
--- a/src/mds/MDS.cc
+++ b/src/mds/MDS.cc
@@ -136,6 +136,8 @@ MDS::MDS(const std::string &n, Messenger *m, MonClient *mc) :
   server = new Server(this);
   locker = new Locker(this, mdcache);
 
+  dispatch_depth = 0;
+
   // clients
   last_client_mdsmap_bcast = 0;
   
@@ -1711,7 +1713,9 @@ bool MDS::ms_dispatch(Message *m)
     m->put();
     ret = true;
   } else {
+    inc_dispatch_depth();
     ret = _dispatch(m);
+    dec_dispatch_depth();
   }
   mds_lock.Unlock();
   return ret;
@@ -1930,6 +1934,9 @@ bool MDS::_dispatch(Message *m)
     }
   }
 
+  if (dispatch_depth > 1)
+    return true;
+
   while (!waiting_for_nolaggy.empty()) {
 
     // stop if we're laggy now!
diff --git a/src/mds/MDS.h b/src/mds/MDS.h
index ac68fea83f3..b84f8a8ac65 100644
--- a/src/mds/MDS.h
+++ b/src/mds/MDS.h
@@ -321,6 +321,7 @@ class MDS : public Dispatcher {
   }
 
  private:
+  int dispatch_depth;
   bool ms_dispatch(Message *m);
   bool ms_get_authorizer(int dest_type, AuthAuthorizer **authorizer, bool force_new);
   bool ms_verify_authorizer(Connection *con, int peer_type,
@@ -409,6 +410,9 @@ class MDS : public Dispatcher {
 
   void request_osdmap(Context *c);
 
+  void inc_dispatch_depth() { ++dispatch_depth; }
+  void dec_dispatch_depth() { --dispatch_depth; }
+
   // messages
   bool _dispatch(Message *m);
 
@@ -436,7 +440,9 @@ public:
     this->mds = mds;
   }
   virtual void finish(int r) {
+    mds->inc_dispatch_depth();
     mds->_dispatch(m);
+    mds->dec_dispatch_depth();
   }
 };