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=-12.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,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 E9FA7C4338F for ; Tue, 17 Aug 2021 13:29:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE4A060F39 for ; Tue, 17 Aug 2021 13:29:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237383AbhHQN3g (ORCPT ); Tue, 17 Aug 2021 09:29:36 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:41172 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239965AbhHQN3e (ORCPT ); Tue, 17 Aug 2021 09:29:34 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 12D6821EBD; Tue, 17 Aug 2021 13:29:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1629206940; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=H/wU2Wsd3qol5Quj2uSDrl/q1yMlnHC3zR55PA35gas=; b=sZy7ZXW8bZELyu57zhhBwZFqJilYWvP2GLW3ixBvDVTNPVas2o0tc2syQJ6ALljweC/H/Y zv7yJSKm6bhjSQ4GF/dDL9olq1AqhzfjuvvtVNUQPG9uwDXzGot+8MaaaLpLlmE9398dF0 anOC5426HbCcm1HZvuaw8mDeZhLujWQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1629206940; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=H/wU2Wsd3qol5Quj2uSDrl/q1yMlnHC3zR55PA35gas=; b=54XuBS3U3pRVIN8gcc8dOeJhhrpPQ8DVziyJN5ksNXnj2ZNvJszPYWcqVY1zWzfx9tmtSe FeQqAPCipfR8wiCA== Received: from ds.suse.cz (ds.suse.cz [10.100.12.205]) by relay2.suse.de (Postfix) with ESMTP id 0A0E2A3B98; Tue, 17 Aug 2021 13:29:00 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id D9C94DA72C; Tue, 17 Aug 2021 15:26:03 +0200 (CEST) Date: Tue, 17 Aug 2021 15:26:03 +0200 From: David Sterba To: Qu Wenruo Cc: linux-btrfs@vger.kernel.org, Chris Murphy Subject: Re: [PATCH] btrfs-progs: mkfs: set super_cache_generation to 0 if we're using free space tree Message-ID: <20210817132603.GL5047@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org, Chris Murphy References: <20210731074240.206263-1-wqu@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210731074240.206263-1-wqu@suse.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Sat, Jul 31, 2021 at 03:42:40PM +0800, 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 Added to devel, thanks.