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=-7.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,USER_AGENT_MUTT 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 8C612C43381 for ; Wed, 27 Mar 2019 14:07:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 622DC2087C for ; Wed, 27 Mar 2019 14:07:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726305AbfC0OHw (ORCPT ); Wed, 27 Mar 2019 10:07:52 -0400 Received: from tartarus.angband.pl ([54.37.238.230]:47440 "EHLO tartarus.angband.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726147AbfC0OHv (ORCPT ); Wed, 27 Mar 2019 10:07:51 -0400 Received: from kilobyte by tartarus.angband.pl with local (Exim 4.92) (envelope-from ) id 1h99DY-0008Em-Eo; Wed, 27 Mar 2019 15:07:48 +0100 Date: Wed, 27 Mar 2019 15:07:48 +0100 From: Adam Borowski To: Qu Wenruo Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH URGENT v1.1 0/2] btrfs-progs: Fix the nobarrier behavior of write Message-ID: <20190327140748.GA30466@angband.pl> References: <20190327094652.16078-1-wqu@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190327094652.16078-1-wqu@suse.com> X-Junkbait: aaron@angband.pl, zzyx@angband.pl User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Wed, Mar 27, 2019 at 05:46:50PM +0800, Qu Wenruo wrote: > This urgent patchset can be fetched from github: > https://github.com/adam900710/btrfs-progs/tree/flush_super > Which is based on v4.20.2. > > Before this patch, btrfs-progs writes to the fs has no barrier at all. > All metadata and superblock are just buffered write, no barrier between > super blocks and metadata writes at all. > > No wonder why even clear space cache can cause serious transid > corruption to the originally good fs. > > Please merge this fix as soon as possible as I really don't want to see > btrfs-progs corrupting any fs any more. How often does this happen in practice? I'm slightly incredulous about btrfs-progs crashing often. Especially that pwrite() is buffered on the kernel side, so we'd need a _kernel_ crash (usually a power loss) to break consistency. Obviously, a potential data loss bug is always something that needs fixing, I'm just wondering about severity. Or do I understand this wrong? Asking because Dimitri John Ledkov stepped down as Debian's maintainer of this package, and I'm taking up the mantle (with Nicholas D Steeves being around) -- modulo any updates other than important bug fixes being on hold because of Debian's freeze. Thus, I wonder if this is important enough to ask for a freeze exception. Meow! -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Did ya know that typing "test -j8" instead of "ctest -j8" ⢿⡄⠘⠷⠚⠋⠀ will make your testsuite pass much faster, and fix bugs? ⠈⠳⣄⠀⠀⠀⠀