HDFS-5268. Merging change r1527087 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1527092 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5265. Merge change r1527093 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1527096 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5260. Merging change r1527113 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1527115 13f79535-47bb-0310-9956-ffa450edef68