HDFS-6409. Merging change r1596739 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1596740 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6433. Merging change r1596742 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1596745 13f79535-47bb-0310-9956-ffa450edef68