From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1756246AbcJMUI3 (ORCPT <rfc822;w@1wt.eu>);
        Thu, 13 Oct 2016 16:08:29 -0400
Received: from zeniv.linux.org.uk ([195.92.253.2]:56780 "EHLO
        ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751453AbcJMUIX (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 13 Oct 2016 16:08:23 -0400
Date: Thu, 13 Oct 2016 21:06:02 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Vineeth Remanan Pillai <vineethp@amazon.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        kamatam@amazon.com, aliguori@amazon.com
Subject: Re: [PATCH] namei: revert old behaviour for filename_lookup with
 LOOKUP_PARENT flag
Message-ID: <20161013200602.GR19539@ZenIV.linux.org.uk>
References: <1476388731-24053-1-git-send-email-vineethp@amazon.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1476388731-24053-1-git-send-email-vineethp@amazon.com>
User-Agent: Mutt/1.7.0 (2016-08-17)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Oct 13, 2016 at 07:58:51PM +0000, Vineeth Remanan Pillai wrote:
> filename_lookup used to return success for non-existing file when called
> with LOOKUP_PARENT flag. This behaviour was changed with
> commit 8bcb77fabd7c ("namei: split off filename_lookupat()
> with LOOKUP_PARENT")
> 
> The above patch split parent lookup functionality to a different function
> filename_parentat and changed all calls to filename_lookup(LOOKUP_PARENT)
> to the new function filename_parentat. But functions like kern_path which
> passed the flags directly to filename_lookup regressed due to this.
> 
> This patch aims to fix the regressed behaviour by calling
> filename_parentat from filename_lookup if the flags contain LOOKUP_PARENT.

What would we want that for?  Details, please.  In particular, I would like
to know how to use that in non-racy way.  What are you doing with it?

PS: "regressed" assumes that there had been any promise of API stability;
no such thing has ever existed.