[PATCH 13/39] mds: don't send resolve message between active MDS

["Yan, Zheng" <zheng.z.yan@xxxxxxxxx>]

From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>

When MDS cluster is resolving, current behavior is sending subtree resolve
message to all other MDS and waiting for all other MDS' resolve message.
The problem is that active MDS can have diffent subtree map due to rename.
Besides gathering active MDS's resolve messages are also racy. The only
function for these messages is disambiguate other MDS' import. We can
replace it by import finish notification.

Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
---
 src/mds/MDCache.cc  | 12 +++++++++---
 src/mds/Migrator.cc | 25 +++++++++++++++++++++++--
 src/mds/Migrator.h  |  3 ++-
 3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index c455a20..73c1d59 100644
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -2517,7 +2517,8 @@ void MDCache::send_subtree_resolves()
        ++p) {
     if (*p == mds->whoami)
       continue;
-    resolves[*p] = new MMDSResolve;
+    if (mds->is_resolve() || mds->mdsmap->is_resolve(*p))
+      resolves[*p] = new MMDSResolve;
   }
 
   // known
@@ -2837,7 +2838,7 @@ void MDCache::handle_resolve(MMDSResolve *m)
 	  migrator->import_reverse(dir);
 	} else {
 	  dout(7) << "ambiguous import succeeded on " << *dir << dendl;
-	  migrator->import_finish(dir);
+	  migrator->import_finish(dir, true);
 	}
 	my_ambiguous_imports.erase(p);  // no longer ambiguous.
       }
@@ -3432,7 +3433,12 @@ void MDCache::rejoin_send_rejoins()
        ++p) {
     CDir *dir = p->first;
     assert(dir->is_subtree_root());
-    assert(!dir->is_ambiguous_dir_auth());
+    if (dir->is_ambiguous_dir_auth()) {
+      // exporter is recovering, importer is survivor.
+      assert(rejoins.count(dir->authority().first));
+      assert(!rejoins.count(dir->authority().second));
+      continue;
+    }
 
     // my subtree?
     if (dir->is_auth())
diff --git a/src/mds/Migrator.cc b/src/mds/Migrator.cc
index 5e53803..833df12 100644
--- a/src/mds/Migrator.cc
+++ b/src/mds/Migrator.cc
@@ -2088,6 +2088,23 @@ void Migrator::import_reverse(CDir *dir)
   }
 }
 
+void Migrator::import_notify_finish(CDir *dir, set<CDir*>& bounds)
+{
+  dout(7) << "import_notify_finish " << *dir << dendl;
+
+  for (set<int>::iterator p = import_bystanders[dir].begin();
+       p != import_bystanders[dir].end();
+       ++p) {
+    MExportDirNotify *notify =
+      new MExportDirNotify(dir->dirfrag(), false,
+			   pair<int,int>(import_peer[dir->dirfrag()], mds->get_nodeid()),
+			   pair<int,int>(mds->get_nodeid(), CDIR_AUTH_UNKNOWN));
+    for (set<CDir*>::iterator i = bounds.begin(); i != bounds.end(); i++)
+      notify->get_bounds().push_back((*i)->dirfrag());
+    mds->send_message_mds(notify, *p);
+  }
+}
+
 void Migrator::import_notify_abort(CDir *dir, set<CDir*>& bounds)
 {
   dout(7) << "import_notify_abort " << *dir << dendl;
@@ -2183,11 +2200,11 @@ void Migrator::handle_export_finish(MExportDirFinish *m)
   CDir *dir = cache->get_dirfrag(m->get_dirfrag());
   assert(dir);
   dout(7) << "handle_export_finish on " << *dir << dendl;
-  import_finish(dir);
+  import_finish(dir, false);
   m->put();
 }
 
-void Migrator::import_finish(CDir *dir) 
+void Migrator::import_finish(CDir *dir, bool notify)
 {
   dout(7) << "import_finish on " << *dir << dendl;
 
@@ -2205,6 +2222,10 @@ void Migrator::import_finish(CDir *dir)
   // remove pins
   set<CDir*> bounds;
   cache->get_subtree_bounds(dir, bounds);
+
+  if (notify)
+    import_notify_finish(dir, bounds);
+
   import_remove_pins(dir, bounds);
 
   map<CInode*, map<client_t,Capability::Export> > cap_imports;
diff --git a/src/mds/Migrator.h b/src/mds/Migrator.h
index 7988f32..2889a74 100644
--- a/src/mds/Migrator.h
+++ b/src/mds/Migrator.h
@@ -273,12 +273,13 @@ protected:
   void import_reverse_unfreeze(CDir *dir);
   void import_reverse_final(CDir *dir);
   void import_notify_abort(CDir *dir, set<CDir*>& bounds);
+  void import_notify_finish(CDir *dir, set<CDir*>& bounds);
   void import_logged_start(dirfrag_t df, CDir *dir, int from,
 			   map<client_t,entity_inst_t> &imported_client_map,
 			   map<client_t,uint64_t>& sseqmap);
   void handle_export_finish(MExportDirFinish *m);
 public:
-  void import_finish(CDir *dir);
+  void import_finish(CDir *dir, bool notify);
 protected:
 
   void handle_export_caps(MExportCaps *m);
-- 
1.7.11.7

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