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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7189FC433EF for ; Thu, 19 May 2022 11:48:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237529AbiESLsr (ORCPT ); Thu, 19 May 2022 07:48:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229878AbiESLsq (ORCPT ); Thu, 19 May 2022 07:48:46 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FA77B41FB for ; Thu, 19 May 2022 04:48:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1652960917; bh=/Q22iYrncIsznpfMX3tEV3deZYopEZJfVhJCBZKWS04=; h=X-UI-Sender-Class:Date:Subject:To:References:From:In-Reply-To; b=KPmxGtQbGmovU0vc3KPL4sZhIiUZKsXYp+2PoEXSsUL49H6UvhMbKaqG1Zppz0cyE 1vOc/mbUK2J2ys4OgXxTAqO4WFIzcpcGg5adVz9sIlg/+VkmZRhcqGxnFWgsxyEu5V srZtXd40N5+1apm05Gx/3s6TZjTNhRjGg7jc13Ec= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.net (mrgmx105 [212.227.17.174]) with ESMTPSA (Nemesis) id 1MFKGP-1o7IuD45gP-00FgWh; Thu, 19 May 2022 13:48:37 +0200 Message-ID: Date: Thu, 19 May 2022 19:48:33 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [RFC ONLY 3/8] btrfs: read raid-stripe-tree from disk Content-Language: en-US To: Johannes Thumshirn , Qu Wenruo , "linux-btrfs@vger.kernel.org" References: <2ccf8b77759a80a09d083446d5adb3d03947394b.1652711187.git.johannes.thumshirn@wdc.com> <6ddec77c-2aa5-d575-0320-3d5bb824bd04@gmx.com> From: Qu Wenruo In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:YDjeyIn874gqFG2/dXlbEud9nBVtVvI9A69924o8IW/O77mv2qm ws17g3Q8+DYNHcr5+TJHSXUUwpvY7R6u57PUFNS8XRMk/e4ADaOfmVaMWReiaV15hIEx2OX wEPwvMov5mxsImRXvtzAF0jG+lpXPYScXwB2+6OiTpfT2s3Src2MOt7RMXNwTQpVWIw4XKs DD0CVboYIPXU3GvEvEIkw== X-UI-Out-Filterresults: notjunk:1;V03:K0:WMqdwiiHRwU=:5+0BC1uGD9OedGqgAlIqrR LVAH7XWKJRejlXu1wtxNw8sW3aP2XhjWHcQOmddOiRZ2tqjxhgGvViM1AE7EdqYlLNGgYcD3g JFIxyjTJls7qATFlen20HpqHznZAj/I3a7na5HSlUJ0kXnuYn0Qvc3rF82MBxEkPosyicII5x fNMKwsRkUE9k8VrfXxu+Ja0PE1NzxsAfyiSau/+2i/ZshncGHbmfXqW6OwXNikQXLoZFZRtqZ YpFlK7a51J8bbkye1ayFqnyMQ3xbX87aggMng4C/0lQhOT5JhjIHWRhLdxwKYPiiCuaarkX6t Cj772jE4f1E91mQXL+DK66UKP1b4dQrLuDk/2mM1wTL6VWGRgFjKg20hi+pPucdP3xzN+By6+ N/EqiQom8p/uiG3FmrZGJ24OEU2p8+FugEpa26XLTL1Dc7z8a+0UVTkEYOWKcx+rxndSBiuQC aLFcLjvWiL5p4X1eGL866TyVj6ywyo00vu3KTCteZ/AF4XLFYHFk0keqd9c/v/sH+9M3+bE2T 3IolGp+0ZWdJKQmmDMnJXc0/l1k6myYWaPA0EbOPKBciT5JY9F2LAjdp99jRAPTaYdQBIz7gL yOREBFhVapYjBtbnnjRDq/tigGpGb7SGQieFwMFsei2CtHfbLZiv4lrhtBexm4I5P1tNX9eFB IG5bol8olVkEJcp4sJ0SuoO5sNKPtqbIHpz4tv9KojeEAep6dIBrCdWEn7w96ZWP4SjFu+XDt QVC1q5m192uJQKbeqf2rw2ENefh9HrLa9cqzFczsM8XfF0SkcUSWSTOC1oY3Qrm4IqXur6IWo PvGe99uK1dzRTssk9IS1xrMWJ4QE8QZ3zk+xlCwho2uEUJlS1kthQhrjLTJHIXjG2IqHXv/qh 2/RVc7+1IhhLjV1NIcXPNM9iqXpwVayqPb2PBwKsCRtS97P4yRIMDR0PqwW9xJQvXtdKDGBJ0 1U232qMk+PV3LeqUJXqQNWFFyRu7uDrpmVArp0Gqt1H2rq9QWt5yMFmOJFMn2gDeiBMJZgSus 5dlBoz6NCusuWT4WbC04/WmTjLPUHsKiWnDxJxczHF2TeiJUgfs2da/QV5IoXBrvGlrjNjB9i Cy5Z9LnDX4Ffwj9gT3g/RU4sWpnes+Gkdh4GASKlar00fjZ6m/hIXBYnQ== Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2022/5/19 19:44, Johannes Thumshirn wrote: > On 19/05/2022 12:37, Qu Wenruo wrote: >>> RAID1 on zoned only needs a stripe tree for data, not for meta-data/sy= stem, >>> so it will work and we can bootstrap from it. >>> >> That sounds good. >> >> And in that case, we don't need to put stripe tree into system chunks a= t >> all. >> >> So this method means, stripe tree is only useful for data. >> Although it's less elegant, it's much saner. > > Yes and no. People still might want to use different metadata profiles t= han > RAID1. For RAID1 variants like RAID1C3/4, I guess we don't need stripe tree eithe= r? What about DUP? If RAID1*/DUP/SINGLE all doesn't need stripe tree, I believe that's already a pretty good profile set for most zoned device users. Personally speaking, it would be much simpler to avoid bothering the stripe tree for metadata. Thanks, Qu > I'd prefer to have system on RAID1 (forced) with stripe trees and > data/meta-data can be whatever. Of cause only RAID5/6 or higher level en= codings > which might need a stripe-tree should be accpeted with a stripe tree.