diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 934daecf552..436bf643551 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -58,6 +58,9 @@ Release 2.1.1-beta - UNRELEASED
     HADOOP-9803. Add a generic type parameter to RetryInvocationHandler.
     (szetszwo)
 
+    HADOOP-9821. ClientId should have getMsb/getLsb methods. 
+    (Tsuyoshi OZAWA via jing9)
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ClientId.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ClientId.java
index 83df4f932d4..c95dbb9faca 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ClientId.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ClientId.java
@@ -33,6 +33,7 @@ public class ClientId {
   
   /** The byte array of a UUID should be 16 */ 
   public static final int BYTE_LENGTH = 16;
+  private static final int shiftWidth = 8;
   
   /**
    * Return clientId as byte[]
@@ -53,17 +54,27 @@ public class ClientId {
     }
     // otherwise should be 16 bytes
     Preconditions.checkArgument(clientId.length == BYTE_LENGTH);
-    long msb = 0;
-    long lsb = 0;
-    for (int i = 0; i < 8; i++) {
-      msb = (msb << 8) | (clientId[i] & 0xff);
-    }
-    for (int i = 8; i < 16; i++) {
-      lsb = (lsb << 8) | (clientId[i] & 0xff);
-    }
+    long msb = getMsb(clientId);
+    long lsb = getLsb(clientId);
     return (new UUID(msb, lsb)).toString();
   }
   
+  public static long getMsb(byte[] clientId) {
+    long msb = 0;
+    for (int i = 0; i < BYTE_LENGTH/2; i++) {
+      msb = (msb << shiftWidth) | (clientId[i] & 0xff);
+    }
+    return msb;
+  }
+  
+  public static long getLsb(byte[] clientId) {
+    long lsb = 0;
+    for (int i = BYTE_LENGTH/2; i < BYTE_LENGTH; i++) {
+      lsb = (lsb << shiftWidth) | (clientId[i] & 0xff);
+    }
+    return lsb;
+  }
+  
   /** Convert from clientId string byte[] representation of clientId */
   public static byte[] toBytes(String id) {
     if (id == null || "".equals(id)) {
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 173e7bce1bb..aeb7ac174ce 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
@@ -70,16 +70,8 @@ public class RetryCache {
           "Invalid clientId - length is " + clientId.length
               + " expected length " + ClientId.BYTE_LENGTH);
       // Convert UUID bytes to two longs
-      long tmp = 0;
-      for (int i=0; i<8; i++) {
-        tmp = (tmp << 8) | (clientId[i] & 0xff);
-      }
-      clientIdMsb = tmp;
-      tmp = 0;
-      for (int i=8; i<16; i++) {
-        tmp = (tmp << 8) | (clientId[i] & 0xff);
-      }
-      clientIdLsb = tmp;
+      clientIdMsb = ClientId.getMsb(clientId);
+      clientIdLsb = ClientId.getLsb(clientId);
       this.callId = callId;
       this.expirationTime = expirationTime;
     }