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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D3E01C433DB for ; Fri, 19 Feb 2021 10:09:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8368D64D92 for ; Fri, 19 Feb 2021 10:09:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230142AbhBSKJI (ORCPT ); Fri, 19 Feb 2021 05:09:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230079AbhBSKJE (ORCPT ); Fri, 19 Feb 2021 05:09:04 -0500 Received: from mail-lj1-x232.google.com (mail-lj1-x232.google.com [IPv6:2a00:1450:4864:20::232]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7EC9C061756 for ; Fri, 19 Feb 2021 02:08:22 -0800 (PST) Received: by mail-lj1-x232.google.com with SMTP id a22so17167669ljp.10 for ; Fri, 19 Feb 2021 02:08:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=gDMqIvxMkTAzaquBSdBIxPhNsL/Xhe78V+a35fM1QBM=; b=gfrr7LErjoquFdnWhifM9aCnOsqiKEb/wgZL0i/+t1qjNf+NXMbyE/HjuNxq8fO9q7 wbAXWNjjkNOxNr+dZW7j0nGw2NRqcLs9oera8bCFyCMGTbb32QRf8Jc7yqMdKz6WH8cE niJPaA3bcoqTLkrwnIuhvpJ4yfZ5CVG9lDoU9PjTRYjXhn6cjWSz4pa2E7C6LyNfcZVb EcfF9fJu7pn3lFJ5ShU8d9mXyndYTl8oFz20k+IvHGHYkVEzt6Z1drg/aDadfDzRpjd3 2bX4bZ9OQ3zARAQ8KDsS6r/SUoYABcZ86JtbKre1/B5yh89JmcDbd56oguEONR7es6y5 UqcQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=gDMqIvxMkTAzaquBSdBIxPhNsL/Xhe78V+a35fM1QBM=; b=fa0OjiowRXmwjUyWj0jpUYwMrhnUAqWTIFh30KsIR2BNJ1iVObhltZ2fvqHTiDYU+h pCOXx9f2gzEgWfFH0BIg76L/aGZyboD/CjAayayJHyXU5C/Nr/tx2OBmBbD0ki73v2yH sCcPuHXWITVlIKMi0PeFyZdiRzntfHCtRUTTc//ndeBhlB3pYHie4wTS40JI8Gx4OVuB J0kkrYB5smNAR12efJJ+rnOCt8cW1GkfZAn+beWTPXsG3hqj+DbOqx58kIO9vgViBXlV jzlQvbHbJ091ZdMCAqrK0VXYW8eiSbtTWcJq4yzifPKnXald1bs+ABershCxnDyhOfYF WkeA== X-Gm-Message-State: AOAM531LqQ/c3cp+to2YssRFeoCGSjuuyklhYjGylGMnNYeVIwwPE14y /vMleTfb8PeUA9MuW58g1OM= X-Google-Smtp-Source: ABdhPJx3rK7JXeffNIz8lk3cU/6mcJZOkL/svAJ4xAIjdTp63KbCPrYBwmOCq1SvUhYVaj/ARLpHvg== X-Received: by 2002:a05:6512:11d1:: with SMTP id h17mr5049187lfr.116.1613729301425; Fri, 19 Feb 2021 02:08:21 -0800 (PST) Received: from [192.168.1.5] ([5.8.48.45]) by smtp.gmail.com with ESMTPSA id i21sm876460lfe.102.2021.02.19.02.08.18 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Feb 2021 02:08:20 -0800 (PST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.7\)) Subject: Re: [PATCH v2] mmp: do not use O_DIRECT when working with regular file From: Alexey Lyashkov In-Reply-To: Date: Fri, 19 Feb 2021 13:08:17 +0300 Cc: Lukas Czerner , linux-ext4@vger.kernel.org, Eric Sandeen Content-Transfer-Encoding: quoted-printable Message-Id: <99A17D19-8764-4027-8B1E-E7ADBE5E2CEE@gmail.com> References: <20210212093719.162065-1-lczerner@redhat.com> <20210218095146.265302-1-lczerner@redhat.com> To: Andreas Dilger , Artem Blagodarenko X-Mailer: Apple Mail (2.3445.9.7) Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Andreas, What about to disable a O_DIRECT global on any block devices in the = e2fsprogs library as this don=E2=80=99t work on 4k disk drives at all ? Instead of fixing an O_DIRECT access with patches sends early. Alex > 19 =D1=84=D0=B5=D0=B2=D1=80. 2021 =D0=B3., =D0=B2 1:20, Andreas Dilger = =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB(=D0=B0): >=20 > On Feb 18, 2021, at 2:51 AM, Lukas Czerner = wrote: >>=20 >> Currently the mmp block is read using O_DIRECT to avoid any caching = that >> may be done by the VM. However when working with regular files this >> creates alignment issues when the device of the host file system has >> sector size larger than the blocksize of the file system in the file >> we're working with. >>=20 >> This can be reproduced with t_mmp_fail test when run on the device = with >> 4k sector size because the mke2fs fails when trying to read the mmp >> block. >>=20 >> Fix it by disabling O_DIRECT when working with regular files. I don't >> think there is any risk of doing so since the file system layer, = unlike >> shared block device, should guarantee cache consistency. >>=20 >> Signed-off-by: Lukas Czerner >> Reviewed-by: Eric Sandeen >=20 > Reviewed-by: Andreas Dilger >=20 >> --- >> v2: Fix comment - it avoids problems when the sector size is larger = not >> smaller than blocksize >>=20 >> lib/ext2fs/mmp.c | 22 +++++++++++----------- >> 1 file changed, 11 insertions(+), 11 deletions(-) >>=20 >> diff --git a/lib/ext2fs/mmp.c b/lib/ext2fs/mmp.c >> index c21ae272..cca2873b 100644 >> --- a/lib/ext2fs/mmp.c >> +++ b/lib/ext2fs/mmp.c >> @@ -57,21 +57,21 @@ errcode_t ext2fs_mmp_read(ext2_filsys fs, blk64_t = mmp_blk, void *buf) >> * regardless of how the io_manager is doing reads, to avoid = caching of >> * the MMP block by the io_manager or the VM. It needs to be = fresh. */ >> if (fs->mmp_fd <=3D 0) { >> + struct stat st; >> int flags =3D O_RDWR | O_DIRECT; >>=20 >> -retry: >> + /* >> + * There is no reason for using O_DIRECT if we're = working with >> + * regular file. Disabling it also avoids problems with >> + * alignment when the device of the host file system has = sector >> + * size larger than blocksize of the fs we're working = with. >> + */ >> + if (stat(fs->device_name, &st) =3D=3D 0 && >> + S_ISREG(st.st_mode)) >> + flags &=3D ~O_DIRECT; >> + >> fs->mmp_fd =3D open(fs->device_name, flags); >> if (fs->mmp_fd < 0) { >> - struct stat st; >> - >> - /* Avoid O_DIRECT for filesystem image files if = open >> - * fails, since it breaks when running on tmpfs. = */ >> - if (errno =3D=3D EINVAL && (flags & O_DIRECT) && >> - stat(fs->device_name, &st) =3D=3D 0 && >> - S_ISREG(st.st_mode)) { >> - flags &=3D ~O_DIRECT; >> - goto retry; >> - } >> retval =3D EXT2_ET_MMP_OPEN_DIRECT; >> goto out; >> } >> -- >> 2.26.2 >>=20 >=20 >=20 > Cheers, Andreas >=20 >=20 >=20 >=20 >=20