From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:61932 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751094AbeBHVLr (ORCPT ); Thu, 8 Feb 2018 16:11:47 -0500 Date: Fri, 9 Feb 2018 08:11:44 +1100 From: Dave Chinner Subject: Re: XFS over device mapper dm-thin device Message-ID: <20180208211144.GD20266@dastard> References: <147a1764-1988-4efd-4f02-e942a1001b4e@redhat.com> <20180202223541.i27bfjij7itt3q5r@destitution> <9c3ec8ff-3595-c889-3abe-7f069292be0d@sandeen.net> <20180205223604.wgacfnsrsaqrwz7n@destitution> <7ed418fa-fa47-1e67-5de8-87d5ba74fbbc@sandeen.net> <20180206061100.yqbc55besdmttkzd@destitution> <89d31e43-a0f7-95f1-080d-1f3bf3d81add@sandeen.net> <20180208055340.GH5433@magnolia> <20180208082526.GC20266@dastard> <744222fe-7774-5086-20b7-48b8326cad99@sandeen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <744222fe-7774-5086-20b7-48b8326cad99@sandeen.net> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Eric Sandeen Cc: "Darrick J. Wong" , Todd Gill , linux-xfs@vger.kernel.org On Thu, Feb 08, 2018 at 08:31:21AM -0600, Eric Sandeen wrote: > > > On 2/8/18 2:25 AM, Dave Chinner wrote: > > On Wed, Feb 07, 2018 at 09:53:40PM -0800, Darrick J. Wong wrote: > >> On Wed, Feb 07, 2018 at 08:35:12PM -0600, Eric Sandeen wrote: > >>> > >>> > >>> On 2/6/18 12:11 AM, Dave Chinner wrote: > >>>> On Mon, Feb 05, 2018 at 04:37:22PM -0600, Eric Sandeen wrote: > >>>>> > >>>>> > >>>>> On 2/5/18 4:36 PM, Dave Chinner wrote: > >>>>>>> In retrospect I think we (I) should have left the "metadata" uuid as > >>>>>>> the one to match the log, not the user-facing one. > >>>>>> I suspect we can just change the log recovery code to accept either > >>>>>> sb_uuid or sb_metauuid if the metauuid feature bit is set and > >>>>>> change xfs_db to not rewrite the log when metauuid is used.... > >>>>>> > >>>>>> Cheers, > >>>>> > >>>>> That was my first thought, but then newer userspace UUID changes > >>>>> won't be mountable on older kernels. I don't think we can just > >>>>> change it w/o some thought re: compatibility... > >>>> > >>>> So maybe we should use a log incompat bit and provide an alternative > >>>> command for the old way of changing the UUID in the log? > >>> > >>> Sure, if we're happy burning an incompat bit for this, sounds good. > >> > >> Or a log incompat bit? > > > > That's what I suggested :P > > And that's what I /meant/, sorry for the lack of specificity ;) So we are all happy to burn a log incompat bit for this? /me wonders how many one liners we can string this out into :) -Dave. -- Dave Chinner david@fromorbit.com