From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7321AFA372A for ; Wed, 16 Oct 2019 11:15:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52E902168B for ; Wed, 16 Oct 2019 11:15:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392629AbfJPLP4 (ORCPT ); Wed, 16 Oct 2019 07:15:56 -0400 Received: from mx2.suse.de ([195.135.220.15]:54724 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727653AbfJPLP4 (ORCPT ); Wed, 16 Oct 2019 07:15:56 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A9622B2D0; Wed, 16 Oct 2019 11:15:54 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 28ABFDA7E3; Wed, 16 Oct 2019 13:16:06 +0200 (CEST) Date: Wed, 16 Oct 2019 13:16:05 +0200 From: David Sterba To: Qu Wenruo Cc: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org Subject: Re: [PATCH v2 0/7] btrfs-progs: Support for BG_TREE feature Message-ID: <20191016111605.GB2751@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Qu Wenruo , Qu Wenruo , linux-btrfs@vger.kernel.org References: <20191008044936.157873-1-wqu@suse.com> <20191014151723.GP2751@twin.jikos.cz> <1d23e48d-8908-5e1c-0c56-7b6ccaef5d27@gmx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1d23e48d-8908-5e1c-0c56-7b6ccaef5d27@gmx.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Tue, Oct 15, 2019 at 08:32:30AM +0800, Qu Wenruo wrote: > > Have we settled the argument whether to use a new tree or key tricks for > > the blocgroup data? I think we have not and will read the previous > > discussions. For a feature like this I want to be sure we understand all > > the pros and cons. > > > Yep, we haven't settled on the whether creating a new tree, or > re-organize the keys. > > But as my last discussion said, I see no obvious pro using the existing > extent tree to hold the new block group item keys, even we can pack them > all together. For me the obvious pro is minimum change to existing set of trees. > And for backup roots, indeed I forgot to add this feature. > But to me that's a minor point, not a show stopper. > > The most important aspect to me is, to allow real world user of super > large fs to try this feature, to prove the usefulness of this design, > other than my on-paper analyse. > > That's why I'm pushing the patchset, even it may not pass any review. > I just want to hold a up-to-date branch so that when some one needs, it > can grab and try them themselves. Ok that's fine and I can add the branch to for-next for ease of testing. I'm working on a prototype that does it the bg item key way, it compiles and creates almost correct filesystem, so I have to fix it before posting. The patches are on top of your bg-tree feature so we could have both in the same kernel for testing.