错误一:
git fatal: unable to write new index file
主要原因就是服务器磁盘空间不够导致的，增加服务器空间就OK了
在百度上面搜索没得到什么有效信息，在gooogle上搜索得到很多有效信息
Finding large directories with something like the following helped clean up some log files that had run wild :
I just ran into the same situation, it turned out that my filesystem was full