HDFS-5886. Merging change r1566468 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1566471 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs-nfs/src/main/java/org/apache/hadoop/hdfs/nfs/nfs3/RpcProgramNfs3.java

@@ -545,7 +545,8 @@ public class RpcProgramNfs3 extends RpcProgram implements Nfs3Interface {
         return new READLINK3Response(Nfs3Status.NFS3ERR_SERVERFAULT);
       }
       if (MAX_READ_TRANSFER_SIZE < target.getBytes().length) {
-        return new READLINK3Response(Nfs3Status.NFS3ERR_IO, postOpAttr, null);
+        return new READLINK3Response(Nfs3Status.NFS3ERR_IO, postOpAttr,
+            new byte[0]);
       }
 
       return new READLINK3Response(Nfs3Status.NFS3_OK, postOpAttr,

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

@@ -69,6 +69,9 @@ Release 2.4.0 - UNRELEASED
     HDFS-5900. Cannot set cache pool limit of "unlimited" via CacheAdmin.
     (wang)
 
+    HDFS-5886. Potential null pointer deference in RpcProgramNfs3#readlink()
+    (brandonli)
+
 Release 2.3.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES