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=-17.7 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,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 A7863C47082 for ; Mon, 7 Jun 2021 23:32:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F5A060C41 for ; Mon, 7 Jun 2021 23:32:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230445AbhFGXeq (ORCPT ); Mon, 7 Jun 2021 19:34:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:60886 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230183AbhFGXep (ORCPT ); Mon, 7 Jun 2021 19:34:45 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9A7DA610E5; Mon, 7 Jun 2021 23:32:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623108773; bh=HC3kkV8oWgBakwkIyHj/LfgohHNYJpZa7N+APwQmgTM=; h=Subject:From:To:Cc:References:Date:In-Reply-To:From; b=GnIIz6tP4VOxXqj4LYLCp3uNVRjR/hgMt4jvZC7DOD4xgdM89zM9hoOsw1zw9wmUk TJDsnl8AfkH7iNIcnJzd3VBPM6SjRmDfjRJS0T3o2tkNjl5RJwZabZpT88YzC5DUpc 61fDnAGFuOy3mmEPG+6tuWmfoGZRY3+MiErPPdmEDPedLhciJKv5Ts97W+30twKOAl uXBEeADxGaRRtzcRwUGDm4GvM8CHyy06waVvhEViuD9e5m8XnaY8zKfwryQh/Am0aV OfpyAtxBYixyt4GwsOIRxFvZMVJra6aKLhmFRI3Z0LrtHcoujRfmjznUpT6rMzGSBj 5ix8PSIAQX18w== Subject: Re: [f2fs-dev] [PATCH v2 RFC] f2fs: fix to force keeping write barrier for strict fsync mode From: Chao Yu To: Chao Yu , jaegeuk@kernel.org Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net References: <20210601101024.119356-1-yuchao0@huawei.com> <9b43a461-e348-f16c-31da-fb70e064d6f8@kernel.org> Message-ID: <979fb5f6-ff4e-e1d4-25d5-4aa61101f878@kernel.org> Date: Tue, 8 Jun 2021 07:32:52 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <9b43a461-e348-f16c-31da-fb70e064d6f8@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Still no time to check this? Thanks, On 2021/6/4 0:00, Chao Yu wrote: > Jaegeuk, > > Any comments on this patch? > > On 2021/6/1 18:10, 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 trigger >> preflush command to persist data in device cache in prior to node >> writeback, it avoids potential data corruption during fsync(). >> >> Signed-off-by: Chao Yu >> --- >> v2: >> - fix this by adding additional preflush command rather than using >> atomic write flow. >>   fs/f2fs/file.c | 14 ++++++++++++++ >>   1 file changed, 14 insertions(+) >> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >> index 7d5311d54f63..238ca2a733ac 100644 >> --- a/fs/f2fs/file.c >> +++ b/fs/f2fs/file.c >> @@ -301,6 +301,20 @@ 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 trigger preflush to keep >> +         * data/node write order to avoid potential data corruption. >> +         */ >> +        if (F2FS_OPTION(sbi).fsync_mode == FSYNC_MODE_STRICT && >> +                                !atomic) { >> +            ret = f2fs_issue_flush(sbi, inode->i_ino); >> +            if (ret) >> +                goto out; >> +        } >>       } >>   go_write: >>       /* >> > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel