From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265395AbUJVRLv (ORCPT ); Fri, 22 Oct 2004 13:11:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265795AbUJVRLD (ORCPT ); Fri, 22 Oct 2004 13:11:03 -0400 Received: from mail-relay-3.tiscali.it ([213.205.33.43]:8088 "EHLO mail-relay-3.tiscali.it") by vger.kernel.org with ESMTP id S271446AbUJVRDS (ORCPT ); Fri, 22 Oct 2004 13:03:18 -0400 Date: Fri, 22 Oct 2004 19:04:03 +0200 From: Andrea Arcangeli To: Andrew Morton Cc: shaggy@austin.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] zap_pte_range should not mark non-uptodate pages dirty Message-ID: <20041022170403.GI14325@dualathlon.random> References: <1098393346.7157.112.camel@localhost> <20041021144531.22dd0d54.akpm@osdl.org> <20041021223613.GA8756@dualathlon.random> <20041021160233.68a84971.akpm@osdl.org> <20041021232059.GE8756@dualathlon.random> <20041021164245.4abec5d2.akpm@osdl.org> <20041022003004.GA14325@dualathlon.random> <20041022012211.GD14325@dualathlon.random> <20041021190320.02dccda7.akpm@osdl.org> <20041022161744.GF14325@dualathlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041022161744.GF14325@dualathlon.random> X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 22, 2004 at 06:17:44PM +0200, Andrea Arcangeli wrote: > So let's forget the mmapped case and let's fix the bh screwup in 2.6. I propose a solution to fix the coherency problem that afflicts 2.6 if invalidate_complete_page fails. If the page is still PagePrivate despite we called try_to_release_page (which means clearing the uptodate bitflag wouldn't help), we should simply return an error to the O_DIRECT writes. That way the error would not be overlooked by the database writing. This is a minium guarantee we have to provide: if we fail invalidate cause the O_DIRECT write to fail. Of course we should return write failures as well in the mmapped case, but let's ignore the mmapped case for now. The real showstopper bug is try_to_release_page failing and preventing the coherency protocol to work even without mmaps. This could never happen in 2.4, in 2.4 as worse ext3 would get an hearth attack, which is much better than silent corruption in the backup. From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 22 Oct 2004 19:04:03 +0200 From: Andrea Arcangeli Subject: Re: [PATCH] zap_pte_range should not mark non-uptodate pages dirty Message-ID: <20041022170403.GI14325@dualathlon.random> References: <1098393346.7157.112.camel@localhost> <20041021144531.22dd0d54.akpm@osdl.org> <20041021223613.GA8756@dualathlon.random> <20041021160233.68a84971.akpm@osdl.org> <20041021232059.GE8756@dualathlon.random> <20041021164245.4abec5d2.akpm@osdl.org> <20041022003004.GA14325@dualathlon.random> <20041022012211.GD14325@dualathlon.random> <20041021190320.02dccda7.akpm@osdl.org> <20041022161744.GF14325@dualathlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041022161744.GF14325@dualathlon.random> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: shaggy@austin.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Fri, Oct 22, 2004 at 06:17:44PM +0200, Andrea Arcangeli wrote: > So let's forget the mmapped case and let's fix the bh screwup in 2.6. I propose a solution to fix the coherency problem that afflicts 2.6 if invalidate_complete_page fails. If the page is still PagePrivate despite we called try_to_release_page (which means clearing the uptodate bitflag wouldn't help), we should simply return an error to the O_DIRECT writes. That way the error would not be overlooked by the database writing. This is a minium guarantee we have to provide: if we fail invalidate cause the O_DIRECT write to fail. Of course we should return write failures as well in the mmapped case, but let's ignore the mmapped case for now. The real showstopper bug is try_to_release_page failing and preventing the coherency protocol to work even without mmaps. This could never happen in 2.4, in 2.4 as worse ext3 would get an hearth attack, which is much better than silent corruption in the backup. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org