From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753042Ab2L0TPd (ORCPT ); Thu, 27 Dec 2012 14:15:33 -0500 Received: from mail.parknet.co.jp ([210.171.160.6]:57382 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751862Ab2L0TPb (ORCPT ); Thu, 27 Dec 2012 14:15:31 -0500 From: OGAWA Hirofumi To: "Darrick J. Wong" 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 Subject: Re: [PATCH 4/4] block: Optionally snapshot page contents to provide stable pages during write References: <20121213080740.23360.16346.stgit@blackbox.djwong.org> <20121213080811.23360.98131.stgit@blackbox.djwong.org> Date: Fri, 28 Dec 2012 04:14:49 +0900 In-Reply-To: <20121213080811.23360.98131.stgit@blackbox.djwong.org> (Darrick J. Wong's message of "Thu, 13 Dec 2012 00:08:11 -0800") Message-ID: <877go3z4ra.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Darrick J. Wong" writes: > diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h > index 780d4c6..0144fbb 100644 > --- a/include/uapi/linux/fs.h > +++ b/include/uapi/linux/fs.h > @@ -69,6 +69,7 @@ struct inodes_stat_t { > #define MS_REMOUNT 32 /* Alter flags of a mounted FS */ > #define MS_MANDLOCK 64 /* Allow mandatory locks on an FS */ > #define MS_DIRSYNC 128 /* Directory modifications are synchronous */ > +#define MS_SNAP_STABLE 256 /* Snapshot pages during writeback, if needed */ > #define MS_NOATIME 1024 /* Do not update access times. */ > #define MS_NODIRATIME 2048 /* Do not update directory access times */ > #define MS_BIND 4096 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. Thanks. -- OGAWA Hirofumi