From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: [patch 9/9] mm: do_sync_mapping_range integrity fix Date: Fri, 31 Oct 2008 11:02:35 -0400 Message-ID: <1225465355.10549.21.camel@think.oraclecorp.com> References: <20081028144715.683011000@suse.de> <20081028145734.706927000@nick.local0.net> <20081030161344.0ed5ca52.akpm@linux-foundation.org> <20081031091616.GF19268@wotan.suse.de> <1225462219.10549.19.camel@think.oraclecorp.com> <20081031143048.GA10506@fogou.chygwyn.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Nick Piggin , Andrew Morton , linux-fsdevel@vger.kernel.org, david@fromorbit.com To: steve@chygwyn.com Return-path: Received: from rgminet01.oracle.com ([148.87.113.118]:43419 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751603AbYJaPDK (ORCPT ); Fri, 31 Oct 2008 11:03:10 -0400 In-Reply-To: <20081031143048.GA10506@fogou.chygwyn.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, 2008-10-31 at 14:30 +0000, steve@chygwyn.com wrote: > > ntfs and gfs2 each have a check that assumes WB_SYNC_NONE means optional > > writeback, both seem fixable with one liners. > > > I doubt that is the case for GFS2... Its a bit subtle, but in order to > ensure that we have the correct lock ordering the code in writepage > for jdata (the only place this occurs, and I assume is what you are > referring to) relies in the fact that because we have a writepages > set for jdata, writepage will only ever be called with WB_SYNC_NONE > and can thus be skipped. Well, if you have a writepages call, writepage is only used by kswapd and is entirely optional (assuming you don't call it yourself ;) -chris