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 E7CF2C433EF for ; Fri, 24 Jun 2022 11:32:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229523AbiFXLcc (ORCPT ); Fri, 24 Jun 2022 07:32:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229446AbiFXLca (ORCPT ); Fri, 24 Jun 2022 07:32:30 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1FAB56756 for ; Fri, 24 Jun 2022 04:32:29 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 831891F8D1; Fri, 24 Jun 2022 11:32:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1656070348; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uiQQlTd/4A1uFmTw8jkaPJu2zf2H+UCf7nwUIqSspHI=; b=vDcTa0wEvq6kiDcQjJisxX3fMncLkaBdz0BmZt4tR5oh06k+Pbc3PeiIKODHhUrU1luwVZ 6FCV8eqIPnlPZ88ZyfOjWITcowT0wInX7kA4gyBsFbuvZYCbb6HwnGAExwmA9SZRa6VatM zQA6Veg0bglyriRs5HPmw1i8M4HQqew= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 4BCB113480; Fri, 24 Jun 2022 11:32:28 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id +QRUD8ygtWIpRwAAMHmgww (envelope-from ); Fri, 24 Jun 2022 11:32:28 +0000 Message-ID: <3e01475c-8296-4cf1-14cd-5774d780b6e2@suse.com> Date: Fri, 24 Jun 2022 14:32:27 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH 1/2] btrfs: remove MIXED_BACKREF sysfs file Content-Language: en-US To: Qu Wenruo , linux-btrfs@vger.kernel.org References: <20220624080123.1521917-1-nborisov@suse.com> <20220624080123.1521917-2-nborisov@suse.com> <21f7eb10-09d7-826c-48c3-ded892984d50@gmx.com> From: Nikolay Borisov In-Reply-To: <21f7eb10-09d7-826c-48c3-ded892984d50@gmx.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 24.06.22 г. 11:13 ч., Qu Wenruo wrote: > > I don't think that's the correct way to go. > > In fact, I think sysfs should have everything, no matter how long > supported it is. I disagree, for things which are considered stand alone features - yes. Like free space tree 2, but for something like backrefs, heck I think we've even removed code which predates mixed backrefs so I'm not entirely use the filesystem can function with that feature turned off, actually it's not possible to create a non-mixedbackref file system since this behavior is hard-coded in btrfs-progs. Also the commit for the backrefs states: This commit introduces a new kind of back reference for btrfs metadata. Once a filesystem has been mounted with this commit, IT WILL NO LONGER BE MOUNTABLE BY OLDER KERNELS.