HADOOP-1063. Fix a race condition in MiniDFSCluster test code. Contributed by Hairong.

git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/trunk@521897 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -6,6 +6,9 @@ Trunk (unreleased changes)
  1. HADOOP-1047.  Fix TestReplication to succeed more reliably.
     (Hairong Kuang via cutting)
 
+ 2. HADOOP-1063.  Fix a race condition in MiniDFSCluster test code.
+    (Hairong Kuang via cutting)
+
 
 Release 0.12.2 - 2007-23-17
 

src/test/org/apache/hadoop/dfs/MiniDFSCluster.java

@@ -48,6 +48,7 @@ public class MiniDFSCluster {
    */
   class NameNodeRunner implements Runnable {
     private NameNode node;
+    private boolean isRunning = true;
     
     public boolean isUp() {
       if (node == null) {
@@ -66,7 +67,11 @@ public class MiniDFSCluster {
      */
     public void run() {
       try {
-        node = new NameNode(conf);
+        synchronized( this ) {
+          if( isRunning ) {
+            node = new NameNode(conf);
+          }
+        }
       } catch (Throwable e) {
         node = null;
         System.err.println("Name node crashed:");
@@ -77,7 +82,8 @@ public class MiniDFSCluster {
     /**
      * Shutdown the name node and wait for it to finish.
      */
-    public void shutdown() {
+    public synchronized void shutdown() {
+      isRunning = false;
       if (node != null) {
         node.stop();
         node.join();
@@ -91,6 +97,7 @@ public class MiniDFSCluster {
   class DataNodeRunner implements Runnable {
     private DataNode node;
     Configuration conf = null;
+    private boolean isRunning = true;
     
     public DataNodeRunner(Configuration conf, File dataDir, int index) {
       this.conf = new Configuration(conf);
@@ -122,10 +129,15 @@ public class MiniDFSCluster {
             }
           }
         }
-        node = new DataNode(conf, conf.get("dfs.datanode.rack", 
-            NetworkTopology.DEFAULT_RACK), dirs);
+        synchronized (this){
+          if (isRunning) {
+            node = new DataNode(conf, conf.get("dfs.datanode.rack", 
+                NetworkTopology.DEFAULT_RACK), dirs);
+          }
+        }
         node.run();
       } catch (Throwable e) {
+        node.shutdown();
         node = null;
         System.err.println("Data node crashed:");
         e.printStackTrace();
@@ -135,7 +147,8 @@ public class MiniDFSCluster {
     /**    
      * Shut down the server and wait for it to finish.
      */
-    public void shutdown() {
+    public synchronized void shutdown() {
+      isRunning = false;
       if (node != null) {
         node.shutdown();
       }
@@ -296,10 +309,7 @@ public class MiniDFSCluster {
         System.out.println("\tNameNode RPC port: " + nameNodePort);
         System.out.println("\tNameNode info port: " + nameNodeInfoPort);
 
-        nameNode.shutdown();
-        for (int idx = 0; idx < nDatanodes; idx++) {
-          dataNodes[idx].shutdown();
-        }
+        shutdown();
         
       } else {
         foundPorts = true;
@@ -324,10 +334,21 @@ public class MiniDFSCluster {
    * Shut down the servers.
    */
   public void shutdown() {
+    System.out.println("Shutting down the cluster");
     for (int idx = 0; idx < nDatanodes; idx++) {
       dataNodes[idx].shutdown();
     }
     nameNode.shutdown();
+    for (int idx = 0; idx < nDatanodes; idx++) {
+      try {
+        dataNodeThreads[idx].join();
+      } catch(InterruptedException e) {
+      }
+    }
+    try {
+      nameNodeThread.join();
+    } catch (InterruptedException e) {
+    }
   }
   
   /**