为什么SVN会破坏我的权限设置?

尝试UMASK:

umask 002

来自UMASK(2):

     The umask() routine sets the process's file mode creation mask to numask
     and returns the previous value of the mask.  The 9 low-order access per-
     mission bits of numask are used by system calls, including open(2),
     mkdir(2), mkfifo(2) and mknod(2) to turn off corresponding bits requested
     in file mode.  (See chmod(2)).  This clearing allows each user to
     restrict the default access to his files.