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 8F563C83F01 for ; Sun, 27 Aug 2023 02:51:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229819AbjH0CvJ (ORCPT ); Sat, 26 Aug 2023 22:51:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229831AbjH0Cux (ORCPT ); Sat, 26 Aug 2023 22:50:53 -0400 Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61FD4FA; Sat, 26 Aug 2023 19:50:51 -0700 (PDT) Received: by mail-qt1-x835.google.com with SMTP id d75a77b69052e-41095b84d8eso13897451cf.2; Sat, 26 Aug 2023 19:50:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1693104650; x=1693709450; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=MIw9Q5r09NfZUTqarX7Iy/jkPLDDRLQ9DQT1RqFnR3Y=; b=kOl2hRWSxWCriLB9sFGb002Zaoa8KZGxKdfMb4QBHLderLFmnWMv7HAY9oKY2hgPt3 rsCsEvkVqdTi+qJGudo1xbfiMGoDNtmKO2scFOdew5c1otjzENK/Jphlk3lGqgubR+ho SbPAbptbz2slPYs4PppPNc/dm+0UDentv8R+hO8eqO6/3sNKWO0CkX/aLpT8pRVSPdV7 C8rGQUcU3A9Jwth5rUbxnckXtpkmtp4TOu51+QEwcc7D1n9h1WDhHteFjyGuZtWJqAyU PERGSnFnDvJz0Mpv6gq6snSpTJIymm5IE976PQYsw56M6/S+oddNSLSLbY/6ajehopjj mdTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693104650; x=1693709450; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=MIw9Q5r09NfZUTqarX7Iy/jkPLDDRLQ9DQT1RqFnR3Y=; b=KTNygRfXvJeUraqBrV1DPaQNYFjmcT3F9oVAEn1MHT9HRdi5Rwwf2uv1TgqNmeVryn s493sWbz8tYlV0FAm4usMRCeJRGr1K4EVKJnHdg7oHZKnoGFHRqzMLe9y+8djBjspVKc XDQ9zZp9xuSMoqhMczhzvJrodLlR2EkmP7/p0YwY4Wz5n5QRLS4h/yXKHONGehe6OKhA Y0jL3tK/pVMdI9BlMpPZH/MccE8PEBhqN8x/WV9AlPc9t8HQ75aIUqRAwOVSHUx9S4nK TCQJlK/QHZesZwbjAr2vKeRQ02OtfVKUBJoqWHgI69PCpzIwVu4kYE0+RuoLPfgtbFcd F9Kw== X-Gm-Message-State: AOJu0YxEZ7WECboiXq1CZae15lxc/6CbrTKISQdiPdYAKVkOzoU9llnO J9vyH8lAy8b0wXxlxfvMPHfL8Lxe0rA= X-Google-Smtp-Source: AGHT+IFKtR6ptyowRAiBmNvqL6eepFITkIOnRdFz5KyEAkPiJJqcLS3WFsT7VTVVAbWOSGjuSpue0Q== X-Received: by 2002:ac8:5909:0:b0:403:c687:bfbb with SMTP id 9-20020ac85909000000b00403c687bfbbmr25298335qty.1.1693104650429; Sat, 26 Aug 2023 19:50:50 -0700 (PDT) Received: from [192.168.0.105] ([103.124.138.83]) by smtp.gmail.com with ESMTPSA id u7-20020a17090341c700b001bdb8f757besm4440223ple.23.2023.08.26.19.50.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 26 Aug 2023 19:50:49 -0700 (PDT) Message-ID: Date: Sun, 27 Aug 2023 09:50:46 +0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Subject: Re: Cache coherency bug: stale reads on /dev/sda1 Content-Language: en-US To: Joshua Hudson , Al Viro Cc: Linux Kernel Mailing List , Linux IDE and libata , Hans de Goede , Jens Axboe , Damien Le Moal , OGAWA Hirofumi References: <20230827020635.GQ3390869@ZenIV> From: Bagas Sanjaya In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/08/2023 09:38, Joshua Hudson wrote: > "Whole disk and all partitions have page caches of their own." > > That's so bad. > > I can think of numerous cases where this will cause problems; including > some I encountered last year and did not understand at the time. Manipulating > EFI partitions through the whole disk device makes sense because FAT filesystems > *know their offset on the disk*, and some of the existing tools really > don't like being > given a partition device. > > There's also the astounding: write stuff to disk, umount everything, > copy one disk to > another using the whole disk device doesn't work because reading the whole disk > yields a stale cache (sometimes). > > On the other hand, I can think of very few cases where the file vs > disk buffer pool > matters, because the loop device is unaffected (writing to a loop > block device is > coherent with the file). > tl;dr: > A: http://en.wikipedia.org/wiki/Top_post > Q: Were do I find info about this thing called top-posting? > A: Because it messes up the order in which people normally read text. > Q: Why is top-posting such a bad thing? > A: Top-posting. > Q: What is the most annoying thing in e-mail? > > A: No. > Q: Should I include quotations after my reply? > > http://daringfireball.net/2007/07/on_top What cases on the loop devices? -- An old man doll... just what I always wanted! - Clara