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 72441C43334 for ; Fri, 3 Jun 2022 19:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349284AbiFCTav (ORCPT ); Fri, 3 Jun 2022 15:30:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349283AbiFCTau (ORCPT ); Fri, 3 Jun 2022 15:30:50 -0400 Received: from mail-lj1-x233.google.com (mail-lj1-x233.google.com [IPv6:2a00:1450:4864:20::233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 631E75A0BA for ; Fri, 3 Jun 2022 12:30:49 -0700 (PDT) Received: by mail-lj1-x233.google.com with SMTP id y29so9438483ljd.7 for ; Fri, 03 Jun 2022 12:30:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=colorremedies-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=PThABRmxbBiN9eWSZXt5B0ivbhoOQ0+Hx/lkUF8W3kM=; b=fsTVcCrq9E4OLjANgqtNcVrw4DbSNCDvnFL3GHrvQ/nhnzTROkvK9XeTdkbFtwynqN uiAQ9dSTeiCRO/qPdfvdx/NSvFLlhvaowpr/t/PjuQbIupzmIoGturPi3+pX23i0Ynwb IXyl+QRnGNSOhSI6uAAVaD35902TbJTmIgxcj/Oum4+dqki22x/zFz+k+BVg3vDUNf5R c8MMSrModfiXZb1tR2j7DNvpPSlwKTKcxss8YZAG03KX5W2WsaKOkAAJNYfMrRpOLyrp Ae/p7m2hR9gAOuOiY/9oRvJ467Aj9kBKc6JELY/Qamq1ZSvIlJrJOExrN2/CgWAPLP1P heHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=PThABRmxbBiN9eWSZXt5B0ivbhoOQ0+Hx/lkUF8W3kM=; b=rgvgKTFlAbhTm+nbXpMHjMmf7DdewmVs+DKO+f1F6ZRPZA59fSU5+XGj4weomIYok2 H+gJUPLgrDXGSAg31BsNN6O5dBzlcRdtKuJtVJ9qyAi7aD/R3nxKxFtFRwMYquqynHPz T79BfqtHOR5egrSxUORx+YniM3mX9mgVN+CxGNzOymHWutQMA6yYPjL0n+loCKUks7Qy Pi+cxO9g/Ivn7hy/zklJz2nYJSgEqMBcDj4BMUHTSiwnJ556614QUxaN4E7IV2iszltL 3rqx9JPw1jQZLPbzqkBB84LftlmbABeCIol3XPLplLiQdzsiUmwdK6PcNijbOL2S7mPb e6Og== X-Gm-Message-State: AOAM530gJywx7wIVcvFvnCyd3Qyn0JVoiyRBvptWLdRSi8YSC9eLN+l0 jfmRQNZG5M/j4oZpfOEkyBVu2ua7vKHmpGMg9vpmGVrYUEtWotFk X-Google-Smtp-Source: ABdhPJw5PQ4ADcd1eYQgpfoVla6JPAAtXZrvaIh+xu+D3AEn11YS9oA3qO+xweAHxhgZSJZVQ44g8V8Ds5j5h0PkN6M= X-Received: by 2002:a2e:9a82:0:b0:255:77fd:1c2c with SMTP id p2-20020a2e9a82000000b0025577fd1c2cmr4752342lji.357.1654284647176; Fri, 03 Jun 2022 12:30:47 -0700 (PDT) MIME-Version: 1.0 References: <7762988d-0a64-695a-4ccd-ba7b51c0754a@gmx.com> <760a98d8-3524-d24f-b5f9-3653ee46661d@gmx.com> In-Reply-To: From: Chris Murphy Date: Fri, 3 Jun 2022 15:30:30 -0400 Message-ID: Subject: Re: Manual intervention options for csum errors To: Matthew Warren Cc: Btrfs BTRFS Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Fri, Jun 3, 2022 at 1:05 PM Matthew Warren wrote: > > > >> This is not a good sign. > > >> > > >> Such bitflip can only happen in memory, as if it's a bitflip from disk, > > >> then it will cause the metadata csum mismatch. > > >> > > >> So this means, your memory is unreliable, and a memtest is strongly > > >> recommended before doing anything. > > > > > > I don't think that's the case. The files were last modified all the > > > way back in 2020, but there hasn't been any file modifications near > > > them since the end of April this year. > > > > Since the bitflip is in csum tree, it doesn't matter if that specific > > file get modified. > > > > Any other file modification can trigger CoW on that csum tree block. > > > > > There's also been 2 scrubs > > > before the last one where there were no issues at all. Does this mean > > > that at some point in the last half month (since that's the time > > > between the last successful scrub and the scrub which errored) BTRFS > > > read and re-wrote the file to disk? > > > > I'd say yes. And it doesn't even need to modify that specific file. > > > > That's why memory bitflip is so concerning. > > > > Thanks, > > Qu > > Would using BTRFS raid 1 add resiliency to this particular issue? No, the corruption from bad RAM will affect both copies. So you really need to do a thorough memory test. -- Chris Murphy