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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 1D00EC3A5A9 for ; Sat, 2 May 2020 04:48:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED5092184D for ; Sat, 2 May 2020 04:48:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ka9q-net.20150623.gappssmtp.com header.i=@ka9q-net.20150623.gappssmtp.com header.b="dzkI3Yjl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726486AbgEBEsg (ORCPT ); Sat, 2 May 2020 00:48:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726463AbgEBEsf (ORCPT ); Sat, 2 May 2020 00:48:35 -0400 Received: from mail-lj1-x242.google.com (mail-lj1-x242.google.com [IPv6:2a00:1450:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 895C4C061A0C for ; Fri, 1 May 2020 21:48:35 -0700 (PDT) Received: by mail-lj1-x242.google.com with SMTP id u15so4455221ljd.3 for ; Fri, 01 May 2020 21:48:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ka9q-net.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=opLaQVYQs6wk/ck/hRA+etLgvzw1B+XX9xQGjMXUpHA=; b=dzkI3YjlULiqcS3xTwMKF4Q0uc6AqL6TluCXc2ZPg4eW1BMQX7PvV5q6Y+yZo0y2co TjIzr/0Qk+CW3zVpm7k0kCm6AL50PknlQf5co6Z4kBzxhf+qL2aQq8jBLEJtOLR++liE vgsDkkJGE8CyL4hluakOBtuxAaOqJJnOhXFsxbUVZzGMFL3X8Pl/5bAGwB/LofCepBBt 7u8jTJ3phoSTGtg5l6bqN0L0dASIbyz2NmrCLJSuIHRKISwHSneTIeLKW4nLCOoJUNwH Q6F4mwGaVaA5e9b5wBs8a/seQlE1a8ddRktHKPfEd6F/c4VPxisDGpRB1/zl+OTg7uh6 /01A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=opLaQVYQs6wk/ck/hRA+etLgvzw1B+XX9xQGjMXUpHA=; b=AHJ3Vu29S65ZQFZl8M9UWKz7eCbL3tRGFcvhwRHTEXuutziNFT7xoPHg4VzqlbMMXN qgOwxEjr4EViMOU10xFm0oXPfMuym2FSI+pDX5fo05sJjy+i5xiNclrwDRH6ytV1uVwJ /r2s9CUq9WRBVs8GAdtYYjZawRRLVhUGxW2hROBV/AErjr+mIJ8ZtE6SOMAvwtWWhPe2 hONZijX/utfxyEWDw/xYvoJdSxCzmfEVvfeiQkakHqEZQMb3n2upp8BgRAhb/AR0hicG tMq2Htg5FVqIGfJc1HAk5TCh04ol5z6OTO5/Y1d/rKuUjrTryJt4YvycRa4R5j65ACNI plcg== X-Gm-Message-State: AGi0PuZQoazAw39HpFc9KbLW9VPq1NWG655jUuZbMewFd6cSn0gruKzI qma7LnvNPOoUXK+Nbtc6lwatRN6E11qGhQ0AF2NvQw== X-Google-Smtp-Source: APiQypLjAiV4abia0Dnf3bo5bT/gHLq6xTg5I9BLkRDylpCrsUtmjiGyajHs/PnbgoW+xlys9HhRNmwb4RI80fmY1tE= X-Received: by 2002:a2e:2245:: with SMTP id i66mr4232627lji.191.1588394913955; Fri, 01 May 2020 21:48:33 -0700 (PDT) MIME-Version: 1.0 References: <8b647a7f-1223-fa9f-57c0-9a81a9bbeb27@ka9q.net> <14a8e382-0541-0f18-b969-ccf4b3254461@ka9q.net> <20200501024753.GE10769@hungrycats.org> <6F06C333-0C27-482A-9AE4-3C0123CC550A@dordea.net> <20200502041826.GH10769@hungrycats.org> In-Reply-To: <20200502041826.GH10769@hungrycats.org> From: Phil Karn Date: Fri, 1 May 2020 21:48:22 -0700 Message-ID: Subject: Re: Extremely slow device removals To: Zygo Blaxell Cc: Alexandru Dordea , Chris Murphy , Btrfs BTRFS Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Thanks for the additional information. I know it's inherently hard to recover from some errors when caching is enabled, like an acknowledged write that can't later be flushed to stable storage. But I had no idea that some drives do gratuitous stuff like dropping the whole write cache on a read error. That does seem pretty indefensible. Has anybody gotten a response from the vendors? Does anybody keep a list of the drives and firmware versions that do this? (Resending because the list requires plain text) --Phil