Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750956AbXAQWoO (ORCPT ); Wed, 17 Jan 2007 17:44:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750957AbXAQWoO (ORCPT ); Wed, 17 Jan 2007 17:44:14 -0500 Received: from moutng.kundenserver.de ([212.227.126.171]:58913 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750955AbXAQWoN (ORCPT ); Wed, 17 Jan 2007 17:44:13 -0500 X-Greylist: delayed 421 seconds by postgrey-1.27 at vger.kernel.org; Wed, 17 Jan 2007 17:44:13 EST Date: Wed, 17 Jan 2007 23:36:10 +0100 (CET) From: Bodo Eggert <7eggert@gmx.de> To: Arjan van de Ven cc: 7eggert@gmx.de, Helge Hafting , Michael Tokarev , Chris Mason , Linus Torvalds , dean gaudet , Viktor , Aubrey , Hua Zhong , Hugh Dickins , linux-kernel@vger.kernel.org, hch@infradead.org, kenneth.w.chen@intel.com, akpm@osdl.org Subject: Re: O_DIRECT question In-Reply-To: <1169013342.3457.60.camel@laptopd505.fenrus.org> Message-ID: References: <7BYkO-5OV-17@gated-at.bofh.it> <7BYul-6gz-5@gated-at.bofh.it> <7C74B-2A4-23@gated-at.bofh.it> <7CaYA-mT-19@gated-at.bofh.it> <7Cpuz-64X-1@gated-at.bofh.it> <7Cz0T-4PH-17@gated-at.bofh.it> <7CBcl-86B-9@gated-at.bofh.it> <7CBvH-52-9@gated-at.bofh.it> <7DyYK-6lE-3@gated-at.bofh.it> <1169013342.3457.60.camel@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-be10.7eggert.dyndns.org-MailScanner-Information: See www.mailscanner.info for information X-be10.7eggert.dyndns.org-MailScanner: Found to be clean X-be10.7eggert.dyndns.org-MailScanner-From: 7eggert@gmx.de X-Provags-ID: kundenserver.de abuse@kundenserver.de login:9b3b2cc444a07783f194c895a09f1de9 X-Provags-ID2: V01U2FsdGVkX1+0A2h9j4iqdvVDRu2rzivmKrNufvH838C3sAg7JdSeGHavSC4LNMp90hKLbThxhqtOOBUqGnWwUza4YwIZ1dqwejLhbg/gcTsU6gzeLfsStQ== Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1369 Lines: 32 On Tue, 16 Jan 2007, Arjan van de Ven wrote: > On Tue, 2007-01-16 at 21:26 +0100, Bodo Eggert wrote: > > Helge Hafting wrote: > > > Michael Tokarev wrote: > > >> But seriously - what about just disallowing non-O_DIRECT opens together > > >> with O_DIRECT ones ? > > >> > > > Please do not create a new local DOS attack. > > > I open some important file, say /etc/resolv.conf > > > with O_DIRECT and just sit on the open handle. > > > Now nobody else can open that file because > > > it is "busy" with O_DIRECT ? > > > > Suspend O_DIRECT access while non-O_DIRECT-fds are open, fdatasync on close? > > .. then any user can impact the operation, performance and reliability > of the database application of another user... sounds like plugging one > hole by making a bigger hole ;) Don't allow other users to access your raw database files then, and if backup kicks in, pausing the database would DTRT for integrety of the backup. For other applications, paused O_DIRECT may very well be a problem, but I can't think of one right now. -- Logic: The art of being wrong with confidence... - 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/