Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757360AbYGKLxS (ORCPT ); Fri, 11 Jul 2008 07:53:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754450AbYGKLxJ (ORCPT ); Fri, 11 Jul 2008 07:53:09 -0400 Received: from mx1.redhat.com ([66.187.233.31]:34840 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751574AbYGKLxG (ORCPT ); Fri, 11 Jul 2008 07:53:06 -0400 Subject: Re: [PATCH 17/18] [GFS2] Remove support for unused and pointless flag From: Steven Whitehouse To: "linux-os (Dick Johnson)" Cc: linux-kernel@vger.kernel.org, cluster-devel@redhat.com In-Reply-To: References: <121577107950-git-send-email-swhiteho@redhat.com> <12157710872782-git-send-email-swhiteho@redhat.com> <1215771089769-git-send-email-swhiteho@redhat.com> <1215771091790-git-send-email-swhiteho@redhat.com> <12157710931623-git-send-email-swhiteho@redhat.com> <12157710954145-git-send-email-swhiteho@redhat.com> <12157710973601-git-send-email-swhiteho@redhat.com> <12157710983282-git-send-email-swhiteho@redhat.com> <12157711013356-git-send-email-swhiteho@redhat.com> <12157711023743-git-send-email-swhiteho@redhat.com> <12157711041157-git-send-email-swhiteho@redhat.com> <1215771106247-git-send-email-swhiteho@redhat.com> <12157711073280-git-send-email-swhiteho@redhat.com> <12157711093284-git-send-email-swhiteho@redhat.com> <12157711133727-git-send-email-swhiteho@redhat.com> <12157711153366-git-send-email-swhiteho@redhat.com> <12157711171692-git-send-email-swhiteho@redhat.com> <1215771119431-git-send-email-swhiteho@redhat.com> Content-Type: text/plain Organization: Red Hat (UK) Ltd (Registered in England and Wales, No. 3798903) Registered office: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 ITE Date: Fri, 11 Jul 2008 12:52:19 +0100 Message-Id: <1215777139.4011.188.camel@quoit> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-2.fc6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1861 Lines: 47 Hi, On Fri, 2008-07-11 at 07:19 -0400, linux-os (Dick Johnson) wrote: > On Fri, 11 Jul 2008 swhiteho@redhat.com wrote: > > > From: Steven Whitehouse > > > > The ability to mark files for direct i/o access when opened > > normally is both unused and pointless, so this patch removes > > support for that feature. > [Snipped...] > > So linux is no longer going to support commercial databases? > Oracle and others need the O_DIRECT attribute. Linux can > probably igonore it, but such an open cannot fail or else > Linux gets thrown out of the commercial enterprise when > an upgrade disables an entire financial institution. > > Cheers, > Dick Johnson > Penguin : Linux version 2.6.22.1 on an i686 machine (5588.28 BogoMips). > My book : http://www.AbominableFirebug.com/ > _ > No, thats not what it means...., but perhaps I could have explained it better. You can still use O_DIRECT flags in open syscalls in exactly the same way as before. What this patch removes is the (never used, and IMHO pointless) feature of being able to set a flag on the inode (via chattr/setattr) to force open's to set O_DIRECT in every case, even when the application didn't ask for it. The reason that its pointless is that applications which don't otherwise support O_DIRECT are very unlikely to supply suitably aligned buffers and I/O requests, so that overriding the O_DIRECT flag for such applications will most likely result in an I/O error. GFS2 will still support O_DIRECT just the same as it has always done, and this doesn't affect any other filesystem's support for that feature either, Steve. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/