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=-18.5 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=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 92A44C4338F for ; Thu, 29 Jul 2021 01:41:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 709E76103A for ; Thu, 29 Jul 2021 01:41:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233304AbhG2Blp (ORCPT ); Wed, 28 Jul 2021 21:41:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:38202 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233140AbhG2Blo (ORCPT ); Wed, 28 Jul 2021 21:41:44 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1BD8360240; Thu, 29 Jul 2021 01:41:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627522901; bh=Jr9u8w5FYOsyL94svzcIWA1IuwFE03Z9VhzfALCkVig=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=li82CMNrpA7V4aOA+hDeNUl2UXE0fNH7q7ceSuOr3hC1FZYpspCb0r1An/mb4xSCD B3oamJtTBC0dlFJe1+lsdARhl5WOutwCXpyow6zGSlzeYzLgKjoikdS/if+Km1Eq+h MJ4X+EJL4vD9H4bX6JUxre68Prm9Hbj7ZY2xPFzvBsK4lym1fVO8ZAeBacqkfrVxdV oh4bjcBBY+wL65WsJsVcJU/lPP4Ac/lAGqpgsf5lJ7nb7L7m+sx/+kZIf+L9ZvFq04 FD1d5yFefHhfWrtQmkYEDmEpJSFJTlu7o/0mTVCmHRHZeJaFkPpUJHSLUf+T+g9jJp 5UXHx4MiLzkKA== Subject: Re: [f2fs-dev] [PATCH v3] f2fs: fix to force keeping write barrier for strict fsync mode To: Jaegeuk Kim Cc: Chao Yu , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net References: <20210720010329.3975-1-chao@kernel.org> <014d1b9d-0698-fda1-0765-cce81d915280@kernel.org> From: Chao Yu Message-ID: Date: Thu, 29 Jul 2021 09:41:40 +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: <014d1b9d-0698-fda1-0765-cce81d915280@kernel.org> 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 Ping, On 2021/7/20 9:19, Chao Yu wrote: > 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 > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel >