Subversion doesn't track either the state or the existence of working copies on the server, so there's no server overhead to keeping working copies around. Likewise, there's no need to let the server know that you're going to delete a working copy.

如果你还是喜欢使用工作副本，直到你再次使用它之前，把其保留在磁盘没有任何错误，任何时候一个svn update命令可以让使用的文件成为最新。

However, if you're definitely not going to use a working copy again, you can safely delete the entire thing using whatever directory removal capabilities your operating system offers. We recommend that before you do so you run svn status and review any files listed in its output that are prefixed with a ? to make certain that they're not of importance.

When Subversion modifies your working copy—either your files or its own administrative state—it tries to do so as safely as possible. Before changing the working copy, Subversion logs its intentions in a private “to-do list”, of sorts. Next, it performs those actions to affect the desired change, holding a lock on the relevant part of the working copy while it works. This prevents other Subversion clients from accessing the working copy mid-change. Finally, Subversion releases its lock and cleans up its private to-do list. Architecturally, this is similar to a journaled filesystem. If a Subversion operation is interrupted (e.g, if the process is killed or if the machine crashes), the private to-do list remains on disk. This allows Subversion to return to that list later to complete any unfinished operations and return your working copy to a consistent state.

This is exactly what svn cleanup does: it searches your working copy and runs any leftover to-do items, removing working copy locks as it completes those operations. If Subversion ever tells you that some part of your working copy is “locked,” run svn cleanup to remedy the problem. The svn status command will inform you about administrative locks in the working copy, too, by displaying an L next to those locked paths:

$ svn status
  L     somedir
M       somedir/foo.c
$ svn cleanup
$ svn status
M       somedir/foo.c

Don't confuse these working copy administrative locks with the user-managed locks that Subversion users create when using the lock-modify-unlock model of concurrent version control; see the sidebar “锁定”的三种含义 for clarification.