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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 4C705C3A5A0 for ; Tue, 20 Aug 2019 01:00:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1CE0822CF4 for ; Tue, 20 Aug 2019 01:00:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566262804; bh=3k09FSAiN1EmDJYOwHzqIY0z6rdM/xIPz2fJfXY0Jd0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=GBeNgGbD6DGhIP1AYQwU8E2iF9kbcmGH/VNEWdkUY+9MeKdMUXwwiHhqJWADrgE+2 BboMaOzZm73f8BCNpSQ6d8/SK71k+5BfUhNklct2VAtn1N4+snsjyyiTHa3pPf2XXW Dlqgl17hgJnNpUJTbgQUBOXChRiivegJ2MNIzIM4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728873AbfHTBAD (ORCPT ); Mon, 19 Aug 2019 21:00:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:48080 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728627AbfHTBAC (ORCPT ); Mon, 19 Aug 2019 21:00:02 -0400 Received: from localhost (unknown [104.132.0.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8B2F322CE8; Tue, 20 Aug 2019 01:00:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566262801; bh=3k09FSAiN1EmDJYOwHzqIY0z6rdM/xIPz2fJfXY0Jd0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kUAUu8VZBvG8TphqNQTLtnrtRoyjj9IAiv0JICGK8sVXH8kfovJr0OYIWhDXlU/kO Ra2ZbTLGqBu6qfYh0SaXYzLXT6+WwcVwzI6wccUMKh3be1h/qrXcDI9mEcSpGoVyYE PZpZcRfLUwHiS2krWglhoAYamsiI9UEtADMq1Has= Date: Mon, 19 Aug 2019 18:00:00 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, chao@kernel.org Subject: Re: [PATCH] f2fs: fix to avoid data corruption by forbidding SSR overwrite Message-ID: <20190820010000.GA45681@jaegeuk-macbookpro.roam.corp.google.com> References: <20190816030334.81035-1-yuchao0@huawei.com> <3349ceea-85ac-173a-81a4-1188ce3804ca@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3349ceea-85ac-173a-81a4-1188ce3804ca@huawei.com> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/19, Chao Yu wrote: > On 2019/8/16 11:03, Chao Yu wrote: > > There is one case can cause data corruption. > > > > - write 4k to fileA > > - fsync fileA, 4k data is writebacked to lbaA > > - write 4k to fileA > > - kworker flushs 4k to lbaB; dnode contain lbaB didn't be persisted yet > > - write 4k to fileB > > - kworker flush 4k to lbaA due to SSR > > - SPOR -> dnode with lbaA will be recovered, however lbaA contains fileB's > > data > > > > One solution is tracking all fsynced file's block history, and disallow > > SSR overwrite on newly invalidated block on that file. > > > > However, during recovery, no matter the dnode is flushed or fsynced, all > > previous dnodes until last fsynced one in node chain can be recovered, > > that means we need to record all block change in flushed dnode, which > > will cause heavy cost, so let's just use simple fix by forbidding SSR > > overwrite directly. > > > > Jaegeuk, > > Please help to add below missed tag to keep this patch being merged in stable > kernel. > > Fixes: 5b6c6be2d878 ("f2fs: use SSR for warm node as well") Done. > > Thanks, > > > Signed-off-by: Chao Yu > > --- > > fs/f2fs/segment.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > > index 9d9d9a050d59..69b3b553ee6b 100644 > > --- a/fs/f2fs/segment.c > > +++ b/fs/f2fs/segment.c > > @@ -2205,9 +2205,11 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del) > > if (!f2fs_test_and_set_bit(offset, se->discard_map)) > > sbi->discard_blks--; > > > > - /* don't overwrite by SSR to keep node chain */ > > - if (IS_NODESEG(se->type) && > > - !is_sbi_flag_set(sbi, SBI_CP_DISABLED)) { > > + /* > > + * SSR should never reuse block which is checkpointed > > + * or newly invalidated. > > + */ > > + if (!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) { > > if (!f2fs_test_and_set_bit(offset, se->ckpt_valid_map)) > > se->ckpt_valid_blocks++; > > } > >