HDFS-4522. LightWeightGSet expects incrementing a volatile to be atomic. Contributed by Colin Patrick McCabe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1455781 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -68,6 +68,9 @@ Release 2.0.5-beta - UNRELEASED
     HDFS-4592. Default values for access time precision are out of sync between
     hdfs-default.xml and the code. (atm)
 
+    HDFS-4522. LightWeightGSet expects incrementing a volatile to be atomic.
+    (Colin Patrick McCabe via atm)
+
 Release 2.0.4-alpha - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/util/LightWeightGSet.java

@@ -72,7 +72,7 @@ public class LightWeightGSet<K, E extends K> implements GSet<K, E> {
   /** Modification version for fail-fast.
    * @see ConcurrentModificationException
    */
-  private volatile int modification = 0;
+  private int modification = 0;
 
   /**
    * @param recommended_length Recommended size of the internal array.