HDFS-2653. svn merge -c 1213586 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1213589 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -88,6 +88,9 @@ Release 0.23.1 - UNRELEASED
 
     HDFS-2614. hadoop dist tarball is missing hdfs headers. (tucu)
  
+    HDFS-2653. DFSClient should cache whether addrs are non-local when
+    short-circuiting is enabled. (eli)
+    
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -32,10 +32,8 @@ import java.net.SocketException;
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 import javax.net.SocketFactory;
 
@@ -514,12 +512,13 @@ public class DFSClient implements java.io.Closeable {
     }
   }
   
-  private static Set<String> localIpAddresses = Collections
-      .synchronizedSet(new HashSet<String>());
+  private static Map<String, Boolean> localAddrMap = Collections
+      .synchronizedMap(new HashMap<String, Boolean>());
   
   private static boolean isLocalAddress(InetSocketAddress targetAddr) {
     InetAddress addr = targetAddr.getAddress();
-    if (localIpAddresses.contains(addr.getHostAddress())) {
+    Boolean cached = localAddrMap.get(addr.getHostAddress());
+    if (cached != null && cached) {
       if (LOG.isTraceEnabled()) {
         LOG.trace("Address " + targetAddr + " is local");
       }
@@ -540,9 +539,7 @@ public class DFSClient implements java.io.Closeable {
     if (LOG.isTraceEnabled()) {
       LOG.trace("Address " + targetAddr + " is local");
     }
-    if (local == true) {
-      localIpAddresses.add(addr.getHostAddress());
-    }
+    localAddrMap.put(addr.getHostAddress(), local);
     return local;
   }