HADOOP-8144. svn merge -c 1325367 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1325368 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -233,6 +233,10 @@ Release 2.0.0 - UNRELEASED
     HADOOP-8270. hadoop-daemon.sh stop action should return 0 for an
     already stopped service. (Roman Shaposhnik via eli)
 
+    HADOOP-8144. pseudoSortByDistance in NetworkTopology doesn't work
+    properly if no local node and first node is local rack node.
+    (Junping Du)
+
   BREAKDOWN OF HADOOP-7454 SUBTASKS
 
     HADOOP-7455. HA: Introduce HA Service Protocol Interface. (suresh)

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

@@ -662,8 +662,8 @@ public class NetworkTopology {
    */
   public void pseudoSortByDistance( Node reader, Node[] nodes ) {
     int tempIndex = 0;
+    int localRackNode = -1;
     if (reader != null ) {
-      int localRackNode = -1;
       //scan the array to find the local node & local rack node
       for(int i=0; i<nodes.length; i++) {
         if(tempIndex == 0 && reader == nodes[i]) { //local node
@@ -693,7 +693,7 @@ public class NetworkTopology {
     }
     
     // put a random node at position 0 if it is not a local/local-rack node
-    if(tempIndex == 0 && nodes.length != 0) {
+    if(tempIndex == 0 && localRackNode == -1 && nodes.length != 0) {
       swap(nodes, 0, r.nextInt(nodes.length));
     }
   }