Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934664AbdC3TIj (ORCPT ); Thu, 30 Mar 2017 15:08:39 -0400 Received: from zimbra.cs.ucla.edu ([131.179.128.68]:44044 "EHLO zimbra.cs.ucla.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934128AbdC3TIh (ORCPT ); Thu, 30 Mar 2017 15:08:37 -0400 X-Greylist: delayed 391 seconds by postgrey-1.27 at vger.kernel.org; Thu, 30 Mar 2017 15:08:37 EDT Subject: Re: RFC: reject unknown open flags To: Linus Torvalds , Christoph Hellwig References: <20170330163327.23920-1-hch@lst.de> <20170330172159.GA24139@lst.de> Cc: Alexander Viro , Linux API , linux-fsdevel , Linux Kernel Mailing List , libc-alpha From: Paul Eggert Organization: UCLA Computer Science Department Message-ID: Date: Thu, 30 Mar 2017 12:02:04 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 570 Lines: 14 On 03/30/2017 11:19 AM, Linus Torvalds wrote: > like "dd" growing an atomic flag and setting it on stdout), 'dd' typically assumes that if a flag O_FOO is not #defined by , then 'dd' can "#define O_FOO 0" and the rest of dd's code can assume O_FOO works "well enough" on older systems. I hope this backward-compatibility hack will suffice for O_ATOMIC too. > I'm assuming you'd also possible want to be able to use F_SETFL to set > O_ATOMIC after the fact Just for fun, one thread can set O_ATOMIC at the same time another thread is doing a 'write'....