From b3d7442b2b0466a9813c431e92caf7d37b6b8495 Mon Sep 17 00:00:00 2001
From: Suresh Srinivas <suresh@apache.org>
Date: Fri, 26 Jul 2013 19:59:06 +0000
Subject: [PATCH] HADOOP-9770. Make RetryCache#state non volatile. Contributed
 by Suresh Srinivas.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1507414 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-common-project/hadoop-common/CHANGES.txt    |  2 ++
 .../java/org/apache/hadoop/ipc/RetryCache.java     | 14 ++++++++------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index ea49079989..685fd05f4c 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -496,6 +496,8 @@ Release 2.1.0-beta - 2013-07-02
     HADOOP-9756. Remove the deprecated getServer(..) methods from RPC.
     (Junping Du via szetszwo)
 
+    HADOOP-9770. Make RetryCache#state non volatile. (suresh)
+
   OPTIMIZATIONS
 
     HADOOP-9150. Avoid unnecessary DNS resolution attempts for logical URIs
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/RetryCache.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/RetryCache.java
index d89dceb508..dab18db80b 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/RetryCache.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/RetryCache.java
@@ -52,7 +52,7 @@ public static class CacheEntry implements LightWeightCache.Entry {
     private static byte SUCCESS = 1;
     private static byte FAILED = 2;
 
-    private volatile byte state = INPROGRESS;
+    private byte state = INPROGRESS;
     
     // Store uuid as two long for better memory utilization
     private final long clientIdMsb; // Most signficant bytes
@@ -63,8 +63,10 @@ public static class CacheEntry implements LightWeightCache.Entry {
     private LightWeightGSet.LinkedElement next;
 
     CacheEntry(byte[] clientId, int callId, long expirationTime) {
-      Preconditions.checkArgument(clientId.length == 16, "Invalid clientId");
-      // Conver UUID bytes to two longs
+      // ClientId must be a UUID - that is 16 octets.
+      Preconditions.checkArgument(clientId.length == 16,
+          "Invalid clientId - must be UUID of size 16 octets");
+      // Convert UUID bytes to two longs
       long tmp = 0;
       for (int i=0; i<8; i++) {
         tmp = (tmp << 8) | (clientId[i] & 0xff);
@@ -116,7 +118,7 @@ synchronized void completed(boolean success) {
       this.notifyAll();
     }
 
-    public boolean isSuccess() {
+    public synchronized boolean isSuccess() {
       return state == SUCCESS;
     }
 
@@ -241,13 +243,13 @@ private CacheEntry waitForCompletion(CacheEntry newEntry) {
 
   private static CacheEntry newEntry(long expirationTime) {
     return new CacheEntry(Server.getClientId(), Server.getCallId(),
-        expirationTime);
+        System.nanoTime() + expirationTime);
   }
 
   private static CacheEntryWithPayload newEntry(Object payload,
       long expirationTime) {
     return new CacheEntryWithPayload(Server.getClientId(), Server.getCallId(),
-        payload, expirationTime);
+        payload, System.nanoTime() + expirationTime);
   }
 
   /** Static method that provides null check for retryCache */