mds: fix discover path race

When C_MDC_RetryDiscoverPath executed, we may have already become
auth mds of base

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

diff --git a/src/mds/CDir.cc b/src/mds/CDir.cc
index a02e7e7e5645f227d33e2dfb6889c40a60384add..1ac26fd1c8d8f13f91111c5a8476c8cf7b6fe7a2 100644 (file)
--- a/src/mds/CDir.cc
+++ b/src/mds/CDir.cc
@@ -1145,11 +1145,14 @@ void CDir::take_sub_waiting(list<Context*>& ls)
     waiting_on_dentry.clear();
     put(PIN_DNWAITER);
   }
-  for (map<inodeno_t, list<Context*> >::iterator p = waiting_on_ino.begin(); 
-       p != waiting_on_ino.end();
-       ++p) 
-    ls.splice(ls.end(), p->second);
-  waiting_on_ino.clear();
+  if (!waiting_on_ino.empty()) {
+    for (map<inodeno_t, list<Context*> >::iterator p = waiting_on_ino.begin(); 
+        p != waiting_on_ino.end();
+        ++p) 
+      ls.splice(ls.end(), p->second);
+    waiting_on_ino.clear();
+    put(PIN_INOWAITER);
+  }
 }
 
 

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index a7d181b02cf0a48169e915d1a2bcc30b39826738..e25df16cf284c9d82cfd2b7bbeb9c714ab862968 100644 (file)
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -9820,7 +9820,12 @@ void MDCache::discover_path(CInode *base,
       onfinish = new C_MDC_RetryDiscoverPath(this, base, snap, want_path, from);
     base->add_waiter(CInode::WAIT_SINGLEAUTH, onfinish);
     return;
-  } 
+  } else if (from == mds->get_nodeid()) {
+    list<Context*> finished;
+    base->take_waiting(CInode::WAIT_DIR, finished);
+    mds->queue_waiters(finished);
+    return;
+  }
 
   if ((want_xlocked && want_path.depth() == 1) ||
       !base->is_waiter_for(CInode::WAIT_DIR) || !onfinish) { // FIXME: weak!
@@ -9868,6 +9873,11 @@ void MDCache::discover_path(CDir *base,
       onfinish = new C_MDC_RetryDiscoverPath2(this, base, snap, want_path);
     base->add_waiter(CDir::WAIT_SINGLEAUTH, onfinish);
     return;
+  } else if (from == mds->get_nodeid()) {
+    list<Context*> finished;
+    base->take_sub_waiting(finished);
+    mds->queue_waiters(finished);
+    return;
   }
 
   if ((want_xlocked && want_path.depth() == 1) ||
@@ -9915,7 +9925,12 @@ void MDCache::discover_ino(CDir *base,
       onfinish = new C_MDC_RetryDiscoverIno(this, base, want_ino);
     base->add_waiter(CDir::WAIT_SINGLEAUTH, onfinish);
     return;
-  } 
+  } else if (from == mds->get_nodeid()) {
+    list<Context*> finished;
+    base->take_sub_waiting(finished);
+    mds->queue_waiters(finished);
+    return;
+  }
 
   if (want_xlocked || !base->is_waiting_for_ino(want_ino) || !onfinish) {
     discover_info_t& d = _create_discover(from);