From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:1644 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750970AbbLJBYp (ORCPT ); Wed, 9 Dec 2015 20:24:45 -0500 Subject: Re: [PATCH v2] btrfs: Introduce new mount option to disable tree log replay To: Chandan Rajendra References: <1449555033-25075-1-git-send-email-quwenruo@cn.fujitsu.com> <2728328.xh2dYaTluQ@localhost.localdomain> CC: From: Qu Wenruo Message-ID: <5668D444.9010808@cn.fujitsu.com> Date: Thu, 10 Dec 2015 09:24:20 +0800 MIME-Version: 1.0 In-Reply-To: <2728328.xh2dYaTluQ@localhost.localdomain> Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Chandan Rajendra wrote on 2015/12/08 15:36 +0530: > On Tuesday 08 Dec 2015 14:10:33 Qu Wenruo wrote: >> Introduce a new mount option "nologreplay" to co-operate with "ro" mount >> option to get real readonly mount, like "norecovery" in ext* and xfs. >> >> Since the new parse_options() need to check new flags at remount time, >> so add a new parameter for parse_options(). >> >> Signed-off-by: Qu Wenruo >> --- >> v2: >> Make RO check mandatory for btrfs_parse_options(). >> Add btrfs_show_options() support for nologreplay. >> >> Document for btrfs-mount(5) will follow after the patch being merged. >> --- >> Documentation/filesystems/btrfs.txt | 7 +++++++ >> fs/btrfs/ctree.h | 4 +++- >> fs/btrfs/disk-io.c | 7 ++++--- >> fs/btrfs/super.c | 29 +++++++++++++++++++++++++---- >> 4 files changed, 39 insertions(+), 8 deletions(-) >> >> diff --git a/Documentation/filesystems/btrfs.txt >> b/Documentation/filesystems/btrfs.txt index c772b47..7ad5b93 100644 >> --- a/Documentation/filesystems/btrfs.txt >> +++ b/Documentation/filesystems/btrfs.txt >> @@ -168,6 +168,13 @@ Options with (*) are default options and will not show >> in the mount options. notreelog >> Enable/disable the tree logging used for fsync and O_SYNC writes. >> >> + nologreplay >> + Disable the log tree replay at mount time to prevent devices get >> + modified. Must be use with 'ro' mount option. >> + A filesystem mounted with the 'nologreplay' option cannot >> + transition to a read-write mount via remount,rw - the filesystem >> + must be unmounted and remounted if read-write access is desired. >> + > > May be the following is slightly better ... > > Disable the log tree replay at mount time to prevent filesystem from getting > modified. Must be used with 'ro' mount option. A filesystem mounted with the > 'nologreplay' option cannot transition to a read-write mount via remount,rw - > the filesystem must be unmounted and mounted back again if read-write access > is desired. Thanks for the review and advice. Since I'm not a native English speaker, I'll follow your advice. (Yeah, remount in my patch is confusing.) I'll update it to v3 with Document update only Thank, Qu > > Aside from above, everything else looks good to me. > > Reviewed-by: Chandan Rajendra >