locks: Allow disabling mandatory locking at compile time

Mandatory locking appears to be almost unused and buggy and there
appears no real interest in doing anything with it.  Since effectively
no one uses the code and since the code is buggy let's allow it to be
disabled at compile time.  I would just suggest removing the code but
undoubtedly that will break some piece of userspace code somewhere.

For the distributions that don't care about this piece of code
this gives a nice starting point to make mandatory locking go away.

Cc: Benjamin Coddington <bcodding@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jeff Layton <jeff.layton@primarydata.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 0d2b326..86c9467 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1191,6 +1191,7 @@ static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
 	return error;
 }
 
+#ifdef CONFIG_MANDATORY_FILE_LOCKING
 /**
  * locks_mandatory_locked - Check for an active lock
  * @file: the file to check
@@ -1289,6 +1290,7 @@ int locks_mandatory_area(int read_write, struct inode *inode,
 }
 
 EXPORT_SYMBOL(locks_mandatory_area);
+#endif /* CONFIG_MANDATORY_FILE_LOCKING */
 
 static void lease_clear_pending(struct file_lock *fl, int arg)
 {