HDFS-6838. Merge r1617361 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1617363 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6582. Merging change r1617366 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1617369 13f79535-47bb-0310-9956-ffa450edef68