From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:65235 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1756785AbcASBg4 (ORCPT ); Mon, 18 Jan 2016 20:36:56 -0500 Subject: Re: [PATCH v5 0/2][PULL REQUEST] Unify 'norecovery' bahavior with other filesystems To: , , References: <1452564313-22007-1-git-send-email-quwenruo@cn.fujitsu.com> <20160114160031.GB4227@twin.jikos.cz> From: Qu Wenruo Message-ID: <569D9321.2050805@cn.fujitsu.com> Date: Tue, 19 Jan 2016 09:36:33 +0800 MIME-Version: 1.0 In-Reply-To: <20160114160031.GB4227@twin.jikos.cz> Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: David Sterba wrote on 2016/01/14 17:00 +0100: > On Tue, Jan 12, 2016 at 10:05:11AM +0800, Qu Wenruo wrote: >> 'Norecovery' mount option is almost a standard for all other >> filesystems, including f2fs, ext4, gfs2, nilfs2, and xfs. >> And since current 'recovery' mount option for btrfs is too generic, it's >> better to change btrfs 'recovery' to 'usebackuproot' and then we can >> safely add 'norecovery' and 'nologreplay' mount option for btrfs. >> >> The patch itself is not huge and already tested by others since v2. >> Only mount option name is changing during all these version changes. > > So we have some kind of consensus about the options, but I think you > need to split the patches further. > > * the new option 'nologreplay' > * keep 'usebackuproot' as a new alias for 'recovery' (with the > deprecation warning) > * new 'norecovery' that switches on 'nologreplay' and 'nousebackuproot' > (ie. the desired "no writes") Hi David, I'm curious about why 'norecovery' needs to imply 'nousebackuproot'. As usebackuproot only affects where btrfs to read the tree/chunk roots. It doesn't mean to change/write anything. RO will ensure superblock is not modified. So I'll only add 'norecovery' as alias for 'nologreplay'. Thanks, Qu > > There is a case in remount, when we start with 'ro,nologreplay' then > remount with just 'ro', the log should be replayed. The other > combinations should be easy. I haven't looked at the patch if it's > implemented that way though. > >