From: OGAWA Hirofumi Subject: Re: [PATCH 4/4] block: Optionally snapshot page contents to provide stable pages during write Date: Tue, 08 Jan 2013 18:44:57 +0900 Message-ID: <87k3roypnq.fsf@devron.myhome.or.jp> References: <20121213080740.23360.16346.stgit@blackbox.djwong.org> <20121213080811.23360.98131.stgit@blackbox.djwong.org> <877go3z4ra.fsf@devron.myhome.or.jp> <20121227210543.GA20103@blackbox.djwong.org> <87y5gjxj2k.fsf@devron.myhome.or.jp> <20130107204436.GO20106@blackbox.djwong.org> Mime-Version: 1.0 Content-Type: text/plain Cc: axboe@kernel.dk, lucho@ionkov.net, jack@suse.cz, ericvh@gmail.com, viro@zeniv.linux.org.uk, rminnich@sandia.gov, tytso@mit.edu, martin.petersen@oracle.com, neilb@suse.de, david@fromorbit.com, Zheng Liu , linux-kernel@vger.kernel.org, hch@infradead.org, linux-fsdevel@vger.kernel.org, adilger.kernel@dilger.ca, bharrosh@panasas.com, jlayton@samba.org, v9fs-developer@lists.sourceforge.net, linux-ext4@vger.kernel.org To: "Darrick J. Wong" Return-path: Received: from mail.parknet.co.jp ([210.171.160.6]:60940 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753110Ab3AHJp2 (ORCPT ); Tue, 8 Jan 2013 04:45:28 -0500 In-Reply-To: <20130107204436.GO20106@blackbox.djwong.org> (Darrick J. Wong's message of "Mon, 7 Jan 2013 12:44:36 -0800") Sender: linux-ext4-owner@vger.kernel.org List-ID: "Darrick J. Wong" writes: > On Fri, Dec 28, 2012 at 06:48:35AM +0900, OGAWA Hirofumi wrote: >> "Darrick J. Wong" writes: >> >> >> I think this flag should be separated into "FS provide stable page" and >> >> "FS needs bounce buffer for stable page". >> >> >> >> My fs (I guess btrfs also) provides stable page by better way, and >> >> doesn't need to wait writeback flags too. What needs is just to avoid >> >> those stable page stuff. >> > >> > How does your fs (are we talking about vfat?) provide stable pages? >> >> Basically it copies the data to another page before modifying data only >> if page has writeback flag. (this is about new fs under development stage.) > > Aha, we're talking about tux3. Since (afaik) there aren't any other > filesystems requesting this flag and tux3 uses the device bdi, should I just > create a patch and send it to you so it'll be included when tux3 goes in? If core doesn't provide, no need to waste your time. I will. Thanks. -- OGAWA Hirofumi