Bulk Operation

HDFS-347 fix various bugs in short circuit read

HDFS-347 allow use of legacy blockreader

HDFS-347 DFSClient: don't create a domain socket unless we need it

HDFS-347 HDFS-347: DN should chmod socket path a+w

HDFS-347 HDFS-347: style cleanups

HDFS-347 DataNode: don't create domain socket unless we need it

HDFS-347 Make a simple doc to describe the usage and design of the shortcircuit read feature

HDFS-347 avoid annoying log message when dfs.domain.socket.path is not set

HDFS-347 TestDomainSocket fails when system umask is set to 0002

HDFS-347 make TestPeerCache not flaky

HDFS-347 HDFS-347: increase default FileInputStreamCache size

HDFS-347 HDFS-347: fix case where local reads get disabled incorrectly

HDFS-347 change dfs.datanode.domain.socket.path to dfs.domain.socket.path

HDFS-347 some small DomainSocket fixes: avoid findbugs warning, change log level, etc.

HDFS-347 Fix bug in DomainSocket path validation

HDFS-347 DFSInputStream#getBlockReader: last retries should ignore the cache

HDFS-347 Bypass UNIX domain socket unit tests when they cannot be run

HDFS-347 DomainSocket should throw AsynchronousCloseException when appropriate

HDFS-347 BlockReaderLocal should use passed file descriptors rather than paths

HDFS-347 Create DomainSocket and DomainPeer and associated unit tests

HDFS-347 Encapsulate connections to peers in Peer and PeerServer classes

HDFS-347 Encapsulate arguments to BlockReaderFactory in a class