Ben Reser <b...@reser.org> writes: > On Wed, Apr 3, 2013 at 12:29 PM, Jeff Trawick <traw...@gmail.com> wrote: >> I'm not aware of any apr_file_lock() use within httpd, so you wouldn't >> regress anything (unless you're using third-party modules that use >> apr_file_lock). But I guess you've introduced a third-party module that >> uses apr_file_lock() or you wouldn't be asking about this? > > Subversion uses apr_file_lock() and by extension so does mod_dav_svn.
The main place we use this is in the FSFS backend. On multi-threaded Unix systems we also use a mutex to ensure that only a single thread in each process locks the file. So the use of fcntl() should be OK here as far as Subversion is concerned. There is also a lock for the BDB backend that is only used for certain admin operations and those operations have a restriction that the caller is responsible for calling the functions in a single-threaded context. These functions are used by the single-threaded svnadmin program. -- Philip
