locks: don't call locks_release_private from locks_copy_lock

All callers of locks_copy_lock pass in a brand new file_lock struct, so
there's no need to call locks_release_private on it. Replace that with
a warning that fires in the event that we receive a target lock that
doesn't look like it's properly initialized.
Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>

fs/locks.c

@@ -285,7 +285,8 @@ EXPORT_SYMBOL(__locks_copy_lock);
 
 void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 {
-	locks_release_private(new);
+	/* "new" must be a freshly-initialized lock */
+	WARN_ON_ONCE(new->fl_ops);
 
 	__locks_copy_lock(new, fl);
 	new->fl_file = fl->fl_file;