lockd: fix file selection in nlmsvc_cancel_blocked

We currently do a lock_to_openmode call based on the arguments from the
NLM_UNLOCK call, but that will always set the fl_type of the lock to
F_UNLCK, and the O_RDONLY descriptor is always chosen.

Fix it to use the file_lock from the block instead.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/lockd/svclock.c

@@ -699,9 +699,10 @@ nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *l
 	block = nlmsvc_lookup_block(file, lock);
 	mutex_unlock(&file->f_mutex);
 	if (block != NULL) {
-		mode = lock_to_openmode(&lock->fl);
-		vfs_cancel_lock(block->b_file->f_file[mode],
-				&block->b_call->a_args.lock.fl);
+		struct file_lock *fl = &block->b_call->a_args.lock.fl;
+
+		mode = lock_to_openmode(fl);
+		vfs_cancel_lock(block->b_file->f_file[mode], fl);
 		status = nlmsvc_unlink_block(block);
 		nlmsvc_release_block(block);
 	}