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=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 14540C4338F for ; Mon, 2 Aug 2021 07:45:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB21360FC1 for ; Mon, 2 Aug 2021 07:45:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232499AbhHBHpZ (ORCPT ); Mon, 2 Aug 2021 03:45:25 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:43546 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232482AbhHBHpY (ORCPT ); Mon, 2 Aug 2021 03:45:24 -0400 Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (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 CCC9B1FF3C; Mon, 2 Aug 2021 07:45:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1627890314; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PebslToj3AADAmIgayvRbSS9q6qQlRuS4L+jp9SZ8sM=; b=OWOywRwJwcZ/vyil34cZH5Q2PL/gews9Avd4aHM/dElpot1UOVagzRuDjotvObJ1n80UJm xeI9N+0cttvj7+8ypRWnsBTgxp+9nqotzCqagn2My8EVSOn3IakzYSpyA0c0Bg77AGftsw PYO4nfaO+Vj7yxQbjSgECMSm47j9Cpk= Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (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 imap1.suse-dmz.suse.de (Postfix) with ESMTPS id 9FD381363C; Mon, 2 Aug 2021 07:45:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id Udq8JIqiB2EreQAAGKfGzw (envelope-from ); Mon, 02 Aug 2021 07:45:14 +0000 Subject: Re: [PATCH] btrfs-progs: mkfs: set super_cache_generation to 0 if we're using free space tree To: Qu Wenruo , linux-btrfs@vger.kernel.org Cc: Chris Murphy References: <20210731074240.206263-1-wqu@suse.com> From: Nikolay Borisov Message-ID: <3ff8d410-3b05-0695-63d8-47284ac288aa@suse.com> Date: Mon, 2 Aug 2021 10:45:14 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210731074240.206263-1-wqu@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 31.07.21 г. 10:42, Qu Wenruo wrote: > [HICCUP] > There is a bug report that mkfs.btrfs -R free-space-tree still makes > kernel to try to cleanup the v1 space cache: > > # mkfs.btrfs -R free-space-tree -f /dev/test/scratch1 > # mount /dev/test/scratch1 /mnt/btrfs > # dmesg | grep cleaning > BTRFS info (device dm-6): cleaning free space cache v1 > > [CAUSE] > By default, mkfs.btrfs will set super cache generation to (u64)-1, which > will inform kernel that the v1 space cache is invalid, needs to > regenerate it. > > But for free space cache tree, kernel will set super cache generation to > 0, to indicate v1 space cache is not in use. > > This means, even we enabled free space tree with all the RO compatible > bits and new tree, as long as super cache generation is not 0, kernel > still consider the fs has some invalid v1 space cache, and will try to > remove them. > > [FIX] > This is not a big deal, but to make the "-R free-space-tree" to really > work as kernel, we also need to set super cache generation to 0. > > Reported-by: Chris Murphy > Link: https://lore.kernel.org/linux-btrfs/CAJCQCtSvgzyOnxtrqQZZirSycEHp+g0eDH5c+Kw9mW=PgxuXmw@mail.gmail.com/ > Signed-off-by: Qu Wenruo Reviewed-by: Nikolay Borisov > --- > kernel-shared/free-space-tree.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel-shared/free-space-tree.c b/kernel-shared/free-space-tree.c > index 2edc7fc716f5..7f589dfef950 100644 > --- a/kernel-shared/free-space-tree.c > +++ b/kernel-shared/free-space-tree.c > @@ -1447,6 +1447,7 @@ int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info) > > btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); > btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); > + btrfs_set_super_cache_generation(fs_info->super_copy, 0); > > ret = btrfs_commit_transaction(trans, tree_root); > if (ret) >