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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 70A65C4338F for ; Fri, 30 Jul 2021 22:20:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A2966103B for ; Fri, 30 Jul 2021 22:20:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232533AbhG3WUS (ORCPT ); Fri, 30 Jul 2021 18:20:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:52672 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234357AbhG3WT5 (ORCPT ); Fri, 30 Jul 2021 18:19:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4853D6108E; Fri, 30 Jul 2021 22:19:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627683592; bh=eymSPNa/TShtYv9U+nLrPRjDCp95bQdCZy22yEiy6Ok=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KXy6Vyl6m36STisPeXh+7/hG5UjvgoprI0Vk6NXpV1dglkyEOYQWHVlz0l6onT51r jz9TLdegV7JdNemfxYZldBxqIQT64qHDoQMUJu4+HXP+eKivaNs7C4Hqris4yHOwGL RQvmv78vATrETUChTHRjNzdXUG+4x84f9ikZ7L/99vRfXERl9qEy6zpBzX1ORWRVls 8znxc3hcCbbjwzoey/QizLY+99cw1XQMRF5LeM9pVwCXfMDDOnzyjy4R76/Jp3rOaY f2rWT/Etm0amxspsLFQ6ALojtxyc4wDjG+IIdUnvOEnb3hsSnq/FrljUJ5835AKZJT DKXt7mfdCU41A== Date: Fri, 30 Jul 2021 15:19:50 -0700 From: Jaegeuk Kim To: Chao Yu Cc: Chao Yu , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH v3] f2fs: fix to force keeping write barrier for strict fsync mode Message-ID: References: <20210720010329.3975-1-chao@kernel.org> <014d1b9d-0698-fda1-0765-cce81d915280@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/29, Chao Yu wrote: > Ping, Added. Thanks. > > 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 > >