HDFS-5252. Merging change r1539740 form trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1539742 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5443. Merge change r1539754 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1539758 13f79535-47bb-0310-9956-ffa450edef68