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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 03952C07E95 for ; Tue, 20 Jul 2021 01:26:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD3C96113C for ; Tue, 20 Jul 2021 01:26:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349790AbhGTAoh (ORCPT ); Mon, 19 Jul 2021 20:44:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:42724 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351779AbhGTAfr (ORCPT ); Mon, 19 Jul 2021 20:35:47 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3809760C3D; Tue, 20 Jul 2021 01:15:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626743758; bh=N/z62KgUlt70d52qf0rQy17/x6qmmv7qYd3KMzJ6Nxg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZETCTxX3OAOwFWGQcAzjbIPD/I1COv1rC7ci3sYpkEutIAjvPhjnXpZDg2g7o29Bt Vt6B8webbLluQGNANjX8IIGFxzupJzKSPCEN3z8dIdGga4f3YW2hqfrSNQiGjPhHmo LplsivAg9j9p95fPsnRu1DmuT+lm8o9XFKKnAXIoPb79Oaj+UjsK1CX58F71rrejZf Px3xJGnNpDGoSaId7+kEI364GMbEn7SpW3YSUV4a+/buy5onnZss84riksSR33t1SW YTEQz0IBDmW734BTktjPW6KThIJhvT0d9xVGPWLz4Dp3jb0f8kw65Z9LLrVTAXM9l+ 9Hpg4MW98X0Jg== Date: Mon, 19 Jul 2021 18:15:56 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: Re: [PATCH v3] f2fs: fix to force keeping write barrier for strict fsync mode Message-ID: References: <20210720010329.3975-1-chao@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210720010329.3975-1-chao@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Wasn't it supposed to be v1? 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 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=-13.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 492CAC07E95 for ; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net Wasn't it supposed to be v1? 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