HADOOP-10953. NetworkTopology#add calls NetworkTopology#toString without holding the netlock (Liang Xie via Colin P. McCabe)

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -889,6 +889,9 @@ Release 2.7.0 - UNRELEASED
     HADOOP-11535 TableMapping related tests failed due to 'successful'
     resolving of invalid test hostname. (Kai Zheng via stevel)
 
+    HADOOP-10953. NetworkTopology#add calls NetworkTopology#toString without
+    holding the netlock (Liang Xie via Colin P. McCabe)
+
 Release 2.6.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetworkTopology.java

@@ -393,14 +393,14 @@ public class NetworkTopology {
    */
   public void add(Node node) {
     if (node==null) return;
-    String oldTopoStr = this.toString();
-    if( node instanceof InnerNode ) {
-      throw new IllegalArgumentException(
-        "Not allow to add an inner node: "+NodeBase.getPath(node));
-    }
     int newDepth = NodeBase.locationToDepth(node.getNetworkLocation()) + 1;
     netlock.writeLock().lock();
     try {
+      String oldTopoStr = this.toString();
+      if( node instanceof InnerNode ) {
+        throw new IllegalArgumentException(
+          "Not allow to add an inner node: "+NodeBase.getPath(node));
+      }
       if ((depthOfAllLeaves != -1) && (depthOfAllLeaves != newDepth)) {
         LOG.error("Error: can't add leaf node " + NodeBase.getPath(node) +
             " at depth " + newDepth + " to topology:\n" + oldTopoStr);