Merge pull request baidu#534 from baidu/master Merge master
Merge pull request baidu#515 from yvxiang/write Hold lock in Block::Write
Merge pull request baidu#511 from yvxiang/seek Support seek write file
Merge pull request baidu#490 from yvxiang/lock Add lock
Merge pull request baidu#393 from lylei/ha.fix fix slave safemode
Merge pull request baidu#283 from yvxiang/fix_log Fix log
Release v0.1
Merge branch 'master' of https://github.com/bluebore/dfs