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=-5.2 required=3.0 tests=BAYES_00, 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 BE19DC433E0 for ; Thu, 11 Feb 2021 15:25:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FFA664E7E for ; Thu, 11 Feb 2021 15:25:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231157AbhBKPYy (ORCPT ); Thu, 11 Feb 2021 10:24:54 -0500 Received: from mx2.suse.de ([195.135.220.15]:49290 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230382AbhBKPWN (ORCPT ); Thu, 11 Feb 2021 10:22:13 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 62B6FACBF; Thu, 11 Feb 2021 15:20:55 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 32C3EDA6E9; Thu, 11 Feb 2021 16:19:01 +0100 (CET) Date: Thu, 11 Feb 2021 16:19:01 +0100 From: David Sterba To: Johannes Thumshirn Cc: "dsterba@suse.cz" , Naohiro Aota , "linux-btrfs@vger.kernel.org" , "dsterba@suse.com" , "hare@suse.com" , "linux-fsdevel@vger.kernel.org" Subject: Re: [PATCH v15 00/42] btrfs: zoned block device support Message-ID: <20210211151901.GD1993@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Johannes Thumshirn , Naohiro Aota , "linux-btrfs@vger.kernel.org" , "dsterba@suse.com" , "hare@suse.com" , "linux-fsdevel@vger.kernel.org" References: <20210210195829.GW1993@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Feb 11, 2021 at 09:58:09AM +0000, Johannes Thumshirn wrote: > On 10/02/2021 21:02, David Sterba wrote: > >> This series implements superblock log writing. It uses two zones as a > >> circular buffer to write updated superblocks. Once the first zone is filled > >> up, start writing into the second zone. The first zone will be reset once > >> both zones are filled. We can determine the postion of the latest > >> superblock by reading the write pointer information from a device. > > > > About that, in this patchset it's still leaving superblock at the fixed > > zone number while we want it at a fixed location, spanning 2 zones > > regardless of their size. > > We'll always need 2 zones or otherwise we won't be powercut safe. Yes we do, that hasn't changed.