SERVER-27078 fix race in ShardRegistry initialization

(cherry picked from commit 77147629b714b1e062c1b406e0aef193cfca36a8)

2 files changed, 2 insertions, 27 deletions

diff --git a/src/mongo/s/client/shard_registry.cpp b/src/mongo/s/client/shard_registry.cpp
index 1931d48ad6e..9de3457f77a 100644
--- a/src/mongo/s/client/shard_registry.cpp
+++ b/src/mongo/s/client/shard_registry.cpp
@@ -101,11 +101,6 @@ ConnectionString ShardRegistry::getConfigServerConnectionString() const {
     return getConfigShard()->getConnString();
 }
 
-void ShardRegistry::rebuildConfigShard() {
-    _data.rebuildConfigShard(_shardFactory.get());
-    invariant(_data.getConfigShard());
-}
-
 StatusWith<shared_ptr<Shard>> ShardRegistry::getShard(OperationContext* txn,
                                                       const ShardId& shardId) {
     // If we know about the shard, return it.
@@ -177,6 +172,8 @@ void ShardRegistry::updateReplSetHosts(const ConnectionString& newConnString) {
     invariant(newConnString.type() == ConnectionString::SET ||
               newConnString.type() == ConnectionString::CUSTOM);  // For dbtests
 
+    // to prevent update config shard connection string during init
+    stdx::unique_lock<stdx::mutex> lock(_reloadMutex);
     _data.rebuildShardIfExists(newConnString, _shardFactory.get());
 }
 
@@ -443,14 +440,6 @@ void ShardRegistryData::shardIdSetDifference(std::set<ShardId>& diff) const {
     }
 }
 
-void ShardRegistryData::rebuildConfigShard(ShardFactory* factory) {
-    stdx::unique_lock<stdx::mutex> rebuildConfigShardLock(_mutex);
-
-    ConnectionString configConnString = _configShard->originalConnString();
-
-    _rebuildShard_inlock(configConnString, factory);
-}
-
 void ShardRegistryData::rebuildShardIfExists(const ConnectionString& newConnString,
                                              ShardFactory* factory) {
     stdx::unique_lock<stdx::mutex> updateConnStringLock(_mutex);
diff --git a/src/mongo/s/client/shard_registry.h b/src/mongo/s/client/shard_registry.h
index e134cc2e2db..94962ec66f6 100644
--- a/src/mongo/s/client/shard_registry.h
+++ b/src/mongo/s/client/shard_registry.h
@@ -97,12 +97,6 @@ public:
      */
     void rebuildShardIfExists(const ConnectionString& newConnString, ShardFactory* factory);
 
-    /**
-     * Rebuilds config shard. The result is to recreate a ReplicaSetMonitor in the case it does
-     * not exist.
-     */
-    void rebuildConfigShard(ShardFactory* factory);
-
 private:
     /**
      * Reads shards docs from the catalog client and fills in maps.
@@ -173,14 +167,6 @@ public:
     bool reload(OperationContext* txn);
 
     /**
-     * Throws out and reconstructs the config shard.  This has the effect that if replica set
-     * monitoring of the config server replica set has stopped (because the set was down for too
-     * long), this will cause the ReplicaSetMonitor to be rebuilt, which will re-trigger monitoring
-     * of the config replica set to resume.
-     */
-    void rebuildConfigShard();
-
-    /**
      * Takes a connection string describing either a shard or config server replica set, looks
      * up the corresponding Shard object based on the replica set name, then updates the
      * ShardRegistry's notion of what hosts make up that shard.