HDFS-5427. Merge change r1538876 from branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.3@1550017 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5443. Merge change r1539758 from branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.3@1550018 13f79535-47bb-0310-9956-ffa450edef68