From: Theodore Tso Subject: Re: [PATCH -V2] ext4: Mark the buffer_heads as dirty and uptodate after prepare_write Date: Fri, 7 Nov 2008 08:33:03 -0500 Message-ID: <20081107133303.GA9543@mit.edu> References: <1226063563-16220-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: cmm@us.ibm.com, sandeen@redhat.com, vallesroc@gmail.com, Solofo.Ramangalahy@bull.net, cryptooctoploid@gmail.com, linux-ext4@vger.kernel.org To: "Aneesh Kumar K.V" Return-path: Received: from www.church-of-our-saviour.ORG ([69.25.196.31]:50559 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750903AbYKGNdW (ORCPT ); Fri, 7 Nov 2008 08:33:22 -0500 Content-Disposition: inline In-Reply-To: <1226063563-16220-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Per discussion on IRC, we've Aneesh and I have concluded that the V1 patch is correct, and in fact calling block_commit_write() when we will be redirtying the page (a) can cause problems if one or more buffer heads on the page is marked for delayed allocation and so bh->block_nr is 0, and (b) wastes disk bandwidth since the page contents will be potentially written out twice. So we'll be going with the V1 version of the patch, and pushing it to Linus ASAP. - Ted