HDFS-5249. Merging change r1525770 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1525771 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5251. Merge 1525787 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1525792 13f79535-47bb-0310-9956-ffa450edef68