From b19d1186ab6d42d6f91360e73638b80eb6346a4c Mon Sep 17 00:00:00 2001
From: Uma Maheswara Rao G <umamahesh@apache.org>
Date: Thu, 8 Mar 2012 18:31:33 +0000
Subject: [PATCH] HDFS-2976. Remove unnecessary method (tokenRefetchNeeded) in
 DFSClient.     (Contributed by Uma Maheswara Rao G)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1298495 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  2 ++
 .../org/apache/hadoop/hdfs/DFSClient.java     | 28 +++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 6cb5290c81a..4e25789ed24 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -53,6 +53,8 @@ Trunk (unreleased changes)
     HDFS-3030. Remove getProtocolVersion and getProtocolSignature from translators.
     (jitendra)
 
+    HDFS-2976. Remove unnecessary method (tokenRefetchNeeded) in DFSClient.
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
index 110a50b2691..074be7eaedf 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
@@ -132,6 +132,7 @@ import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.security.token.TokenRenewer;
 import org.apache.hadoop.util.DataChecksum;
 import org.apache.hadoop.util.Progressable;
+import org.apache.hadoop.hdfs.security.token.block.InvalidBlockTokenException;
 
 import com.google.common.base.Preconditions;
 
@@ -670,6 +671,33 @@ public class DFSClient implements java.io.Closeable {
     return false;
   }
   
+  /**
+   * Should the block access token be refetched on an exception
+   * 
+   * @param ex Exception received
+   * @param targetAddr Target datanode address from where exception was received
+   * @return true if block access token has expired or invalid and it should be
+   *         refetched
+   */
+  private static boolean tokenRefetchNeeded(IOException ex,
+      InetSocketAddress targetAddr) {
+    /*
+     * Get a new access token and retry. Retry is needed in 2 cases. 1) When
+     * both NN and DN re-started while DFSClient holding a cached access token.
+     * 2) In the case that NN fails to update its access key at pre-set interval
+     * (by a wide margin) and subsequently restarts. In this case, DN
+     * re-registers itself with NN and receives a new access key, but DN will
+     * delete the old access key from its memory since it's considered expired
+     * based on the estimated expiration date.
+     */
+    if (ex instanceof InvalidBlockTokenException || ex instanceof InvalidToken) {
+      LOG.info("Access token was invalid when connecting to " + targetAddr
+          + " : " + ex);
+      return true;
+    }
+    return false;
+  }
+  
   /**
    * Cancel a delegation token
    * @param token the token to cancel