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 B7673C433FE for ; Wed, 12 Oct 2022 13:01:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229808AbiJLNBz (ORCPT ); Wed, 12 Oct 2022 09:01:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229785AbiJLNBy (ORCPT ); Wed, 12 Oct 2022 09:01:54 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ECCC42700; Wed, 12 Oct 2022 06:01:52 -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-out1.suse.de (Postfix) with ESMTPS id 96FD221E5F; 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Wed, 12 Oct 2022 13:01:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id okVlEb+6RmMnbQAAMHmgww (envelope-from ); Wed, 12 Oct 2022 13:01:51 +0000 Date: Wed, 12 Oct 2022 15:01:45 +0200 From: David Sterba To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Qu Wenruo , David Sterba , clm@fb.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org Subject: Re: [PATCH AUTOSEL 6.0 41/46] btrfs: relax block-group-tree feature dependency checks Message-ID: <20221012130145.GY13389@suse.cz> Reply-To: dsterba@suse.cz References: <20221011145015.1622882-1-sashal@kernel.org> <20221011145015.1622882-41-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221011145015.1622882-41-sashal@kernel.org> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Tue, Oct 11, 2022 at 10:50:09AM -0400, Sasha Levin wrote: > From: Qu Wenruo > > [ Upstream commit d7f67ac9a928fa158a95573406eac0a887bbc28c ] > > [BUG] > When one user did a wrong attempt to clear block group tree, which can > not be done through mount option, by using "-o clear_cache,space_cache=v2", > it will cause the following error on a fs with block-group-tree feature: > > BTRFS info (device dm-1): force clearing of disk cache > BTRFS info (device dm-1): using free space tree > BTRFS info (device dm-1): clearing free space tree > BTRFS info (device dm-1): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1) > BTRFS info (device dm-1): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2) > BTRFS error (device dm-1): block-group-tree feature requires fres-space-tree and no-holes > BTRFS error (device dm-1): super block corruption detected before writing it to disk > BTRFS: error (device dm-1) in write_all_supers:4318: errno=-117 Filesystem corrupted (unexpected superblock corruption detected) > BTRFS warning (device dm-1: state E): Skipping commit of aborted transaction. > > [CAUSE] > Although the dependency for block-group-tree feature is just an > artificial one (to reduce test matrix), we put the dependency check into > btrfs_validate_super(). > > This is too strict, and during space cache clearing, we will have a > window where free space tree is cleared, and we need to commit the super > block. > > In that window, we had block group tree without v2 cache, and triggered > the artificial dependency check. > > This is not necessary at all, especially for such a soft dependency. > > [FIX] > Introduce a new helper, btrfs_check_features(), to do all the runtime > limitation checks, including: > > - Unsupported incompat flags check > > - Unsupported compat RO flags check > > - Setting missing incompat flags > > - Artificial feature dependency checks > Currently only block group tree will rely on this. > > - Subpage runtime check for v1 cache > > With this helper, we can move quite some checks from > open_ctree()/btrfs_remount() into it, and just call it after > btrfs_parse_options(). > > Now "-o clear_cache,space_cache=v2" will not trigger the above error > anymore. > > Signed-off-by: Qu Wenruo > Reviewed-by: David Sterba > [ edit messages ] > Signed-off-by: David Sterba > Signed-off-by: Sasha Levin Please drop this from the stable queue, it's for an unreleased feature (ETA 6.1).