merge -r 1379092:1379093 from trunk. FIXES: HDFS-3861

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1379097 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -116,6 +116,8 @@ Release 0.23.3 - UNRELEASED
     HDFS-3177. Update DFSClient and DataXceiver to handle different checkum
     types in file checksum computation.  (Kihwal Lee via daryn)
 
+    HDFS-3861. Deadlock in DFSClient (Kihwal Lee via daryn)
+
 Release 0.23.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -399,7 +399,7 @@ public class DFSClient implements java.io.Closeable {
    *  until the first output stream is created. The same instance will
    *  be returned until all output streams are closed.
    */
-  public synchronized LeaseRenewer getLeaseRenewer() throws IOException {
+  public LeaseRenewer getLeaseRenewer() throws IOException {
       return LeaseRenewer.getInstance(authority, ugi, this);
   }