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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 33233C07E95 for ; Tue, 20 Jul 2021 01:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2F6A60C3D for ; Tue, 20 Jul 2021 01:21:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240989AbhGTAlB (ORCPT ); Mon, 19 Jul 2021 20:41:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:43114 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345169AbhGTAij (ORCPT ); Mon, 19 Jul 2021 20:38:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1175160C3D; Tue, 20 Jul 2021 01:19:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626743952; bh=IYePbHY2sD319NqCb3FPOmyytqnU6F0vrlI4hwuRhJY=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=sl++5t77WUdsoedpKVHWuNLdUkd7yIt6kDWHypUlIlbHKDCcT3eI57gRiOexFHLYP uWjcvX2ChsNW3UMSCF9dx0jUOj7G2tr2TsDU7YciTHV2ERyRXjSjwYLdFTKk8MGZyR 4fYV4F6NyH8oDpi0MvMzd5uQ8ifu0PstUG8QjquyL+im514arw43paScUbbYmEaqNY H72bhcgqIvOqCTgP0FEQOYUDDTj3di4IMwwJtz8jcgeMeKZ+DEu+xlne96FNMSLfEx RxWMbzn+y8Euv3gYess8USQxn+YSH5l0T45FIHjMJ10TSIUVBr/n4ioFW2yQWHbSkE +LADWSWdVS1mg== Subject: Re: [PATCH v3] f2fs: fix to force keeping write barrier for strict fsync mode To: Jaegeuk Kim Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu References: <20210720010329.3975-1-chao@kernel.org> From: Chao Yu Message-ID: <014d1b9d-0698-fda1-0765-cce81d915280@kernel.org> Date: Tue, 20 Jul 2021 09:19:10 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/7/20 9:15, Jaegeuk Kim wrote: > Wasn't it supposed to be v1? I skip IPU case for v1, and resend it as v3, is it fine to you? Thanks, > > On 07/20, Chao Yu wrote: >> [1] https://www.mail-archive.com/linux-f2fs-devel@lists.sourceforge.net/msg15126.html >> >> As [1] reported, if lower device doesn't support write barrier, in below >> case: >> >> - write page #0; persist >> - overwrite page #0 >> - fsync >> - write data page #0 OPU into device's cache >> - write inode page into device's cache >> - issue flush >> >> If SPO is triggered during flush command, inode page can be persisted >> before data page #0, so that after recovery, inode page can be recovered >> with new physical block address of data page #0, however there may >> contains dummy data in new physical block address. >> >> Then what user will see is: after overwrite & fsync + SPO, old data in >> file was corrupted, if any user do care about such case, we can suggest >> user to use STRICT fsync mode, in this mode, we will force to use atomic >> write sematics to keep write order in between data/node and last node, >> so that it avoids potential data corruption during fsync(). >> >> Signed-off-by: Chao Yu >> --- >> fs/f2fs/file.c | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) >> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >> index 6afd4562335f..00b45876eaa1 100644 >> --- a/fs/f2fs/file.c >> +++ b/fs/f2fs/file.c >> @@ -301,6 +301,18 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end, >> f2fs_exist_written_data(sbi, ino, UPDATE_INO)) >> goto flush_out; >> goto out; >> + } else { >> + /* >> + * for OPU case, during fsync(), node can be persisted before >> + * data when lower device doesn't support write barrier, result >> + * in data corruption after SPO. >> + * So for strict fsync mode, force to use atomic write sematics >> + * to keep write order in between data/node and last node to >> + * avoid potential data corruption. >> + */ >> + if (F2FS_OPTION(sbi).fsync_mode == >> + FSYNC_MODE_STRICT && !atomic) >> + atomic = true; >> } >> go_write: >> /* >> -- >> 2.22.1