add a lock not allowing connecting to nodes while shutting down

src/main/java/org/elasticsearch/transport/netty/NettyTransport.java

@@ -65,6 +65,8 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import static org.elasticsearch.common.network.NetworkService.TcpSettings.*;
 import static org.elasticsearch.common.settings.ImmutableSettings.Builder.EMPTY_SETTINGS;
@@ -138,6 +140,9 @@ public class NettyTransport extends AbstractLifecycleComponent<Transport> implem
     private volatile BoundTransportAddress boundAddress;
 
     private final Object[] connectMutex;
+    // this lock is here to make sure we close this transport and disconnect all the client nodes
+    // connections while no connect operations is going on... (this might help with 100% CPU when stopping the transport?)
+    private final ReadWriteLock globalLock = new ReentrantReadWriteLock();
 
     public NettyTransport(ThreadPool threadPool) {
         this(EMPTY_SETTINGS, threadPool, new NetworkService(EMPTY_SETTINGS));
@@ -367,6 +372,7 @@ public class NettyTransport extends AbstractLifecycleComponent<Transport> implem
         threadPool.generic().execute(new Runnable() {
             @Override
             public void run() {
+                globalLock.writeLock().lock();
                 try {
                     for (Iterator<NodeChannels> it = connectedNodes.values().iterator(); it.hasNext(); ) {
                         NodeChannels nodeChannels = it.next();
@@ -403,6 +409,7 @@ public class NettyTransport extends AbstractLifecycleComponent<Transport> implem
                         clientBootstrap = null;
                     }
                 } finally {
+                    globalLock.writeLock().unlock();
                     latch.countDown();
                 }
             }
@@ -535,12 +542,20 @@ public class NettyTransport extends AbstractLifecycleComponent<Transport> implem
 
     public void connectToNode(DiscoveryNode node, boolean light) {
         if (!lifecycle.started()) {
-            throw new ElasticSearchIllegalStateException("Can't add nodes to a stopped transport");
+            throw new ElasticSearchIllegalStateException("can't add nodes to a stopped transport");
         }
         if (node == null) {
-            throw new ConnectTransportException(null, "Can't connect to a null node");
+            throw new ConnectTransportException(null, "can't connect to a null node");
+        }
+        globalLock.readLock().lock();
+        try {
+            if (!lifecycle.started()) {
+                throw new ElasticSearchIllegalStateException("can't add nodes to a stopped transport");
             }
             synchronized (connectLock(node.id())) {
+                if (!lifecycle.started()) {
+                    throw new ElasticSearchIllegalStateException("can't add nodes to a stopped transport");
+                }
                 try {
                     NodeChannels nodeChannels = connectedNodes.get(node);
                     if (nodeChannels != null) {
@@ -576,6 +591,9 @@ public class NettyTransport extends AbstractLifecycleComponent<Transport> implem
                     throw new ConnectTransportException(node, "General node connection failure", e);
                 }
             }
+        } finally {
+            globalLock.readLock().unlock();
+        }
     }
 
     private NodeChannels connectToChannelsLight(DiscoveryNode node) {