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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 3C040ECE561 for ; Wed, 19 Sep 2018 02:37:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DBE4A214C2 for ; Wed, 19 Sep 2018 02:37:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DBE4A214C2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726375AbeISIN1 (ORCPT ); Wed, 19 Sep 2018 04:13:27 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:12183 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725829AbeISIN1 (ORCPT ); Wed, 19 Sep 2018 04:13:27 -0400 Received: from DGGEMS411-HUB.china.huawei.com (unknown [10.3.19.211]) by Forcepoint Email with ESMTP id 92709682A6104; Wed, 19 Sep 2018 10:37:49 +0800 (CST) Received: from [127.0.0.1] (10.111.220.140) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.399.0; Wed, 19 Sep 2018 10:37:44 +0800 Subject: Re: [PATCH] f2fs: avoid GC causing encrypted file corrupted To: Jaegeuk Kim CC: , , , , , , , , References: <1537274393-78441-1-git-send-email-yunlong.song@huawei.com> <20180918181705.GG91945@jaegeuk-macbookpro.roam.corp.google.com> From: Yunlong Song Message-ID: <8f0e5fc7-cb22-47a0-30e8-4e3a25891e8b@huawei.com> Date: Wed, 19 Sep 2018 10:37:12 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20180918181705.GG91945@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.111.220.140] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/9/19 2:17, Jaegeuk Kim wrote: > On 09/18, Yunlong Song wrote: >> The encrypted file may be corrupted by GC in following case: >> >> Time 1: | segment 1 blkaddr = A | GC -> | segment 2 blkaddr = B | >> Encrypted block 1 is moved from blkaddr A of segment 1 to blkaddr B of >> segment 2, >> >> Time 2: | segment 1 blkaddr = B | GC -> | segment 3 blkaddr = C | > segment 2 blkaddr = B? Sorry for typing error. Yes. > >> Before page 1 is written back and if segment 2 become a victim, then >> page 1 is moved from blkaddr B of segment 2 to blkaddr Cof segment 3, > C of ? Yes. > >> during the GC process of Time 2, f2fs should wait for page 1 written back >> before reading it, or move_data_block will read a garbage block from >> blkaddr B since page is not written back to blkaddr B yet. > move_data_block() checks PageUptodate() so it won't get garbage, yes? > So, does ra_data_block need to check PageUptodate? You mean if page 1 is read from blkaddr B before it is written back to blkaddr B, then the page will become non-uptodate status, why? Is it because __read_end_io checks "(bio->bi_status || PageError(page))" and ClearPageUptodate(page)? > >> Commit 6aa58d8a ("f2fs: readahead encrypted block during GC") introduce >> ra_data_block to read encrypted block, but it forgets to add >> f2fs_wait_on_page_writeback to avoid racing between GC and flush. >> >> Signed-off-by: Yunlong Song >> --- >> fs/f2fs/gc.c | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >> index a4c1a41..c55fb62 100644 >> --- a/fs/f2fs/gc.c >> +++ b/fs/f2fs/gc.c >> @@ -641,6 +641,14 @@ static int ra_data_block(struct inode *inode, pgoff_t index) >> fio.page = page; >> fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr; >> >> + /* >> + * don't cache encrypted data into meta inode until previous dirty >> + * data were writebacked to avoid racing between GC and flush. >> + */ >> + f2fs_wait_on_page_writeback(page, DATA, true); >> + >> + f2fs_wait_on_block_writeback(inode, dn.data_blkaddr); >> + >> fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi), >> dn.data_blkaddr, >> FGP_LOCK | FGP_CREAT, GFP_NOFS); >> @@ -723,6 +731,8 @@ static void move_data_block(struct inode *inode, block_t bidx, >> */ >> f2fs_wait_on_page_writeback(page, DATA, true); >> >> + f2fs_wait_on_block_writeback(inode, dn.data_blkaddr); >> + >> err = f2fs_get_node_info(fio.sbi, dn.nid, &ni); >> if (err) >> goto put_out; >> -- >> 1.8.5.2 > . > -- Thanks, Yunlong Song