HDFS-5548. Merging change r1545756 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1545759 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5561. Merge change r1545791 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1545793 13f79535-47bb-0310-9956-ffa450edef68