fcntl(F_SETSIG) fix

fcntl(F_SETSIG) no longer works on leases because
lease_release_private_callback() gets called as the lease is copied in
order to initialise it.

The problem is that lease_alloc() performs an unnecessary initialisation,
which sets the lease_manager_ops.  Avoid the problem by allocating the
target lease structure using locks_alloc_lock().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

fs/locks.c

@@ -1356,8 +1356,9 @@ static int __setlease(struct file *filp, long arg, struct file_lock **flp)
 	if (!leases_enable)
 		goto out;
 
-	error = lease_alloc(filp, arg, &fl);
-	if (error)
+	error = -ENOMEM;
+	fl = locks_alloc_lock();
+	if (fl == NULL)
 		goto out;
 
 	locks_copy_lock(fl, lease);
@@ -1365,6 +1366,7 @@ static int __setlease(struct file *filp, long arg, struct file_lock **flp)
 	locks_insert_lock(before, fl);
 
 	*flp = fl;
+	error = 0;
 out:
 	return error;
 }