From patchwork Thu Mar 30 06:32:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 9652993 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9278C60349 for ; Thu, 30 Mar 2017 06:33:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8447227F90 for ; Thu, 30 Mar 2017 06:33:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 796032845F; Thu, 30 Mar 2017 06:33:08 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2540B27F90 for ; Thu, 30 Mar 2017 06:33:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755350AbdC3GdE (ORCPT ); Thu, 30 Mar 2017 02:33:04 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:50136 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1755186AbdC3GdD (ORCPT ); Thu, 30 Mar 2017 02:33:03 -0400 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="17166402" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 30 Mar 2017 14:32:59 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id ED56549F9A69; Thu, 30 Mar 2017 14:32:56 +0800 (CST) Received: from localhost.localdomain (10.167.226.34) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.319.2; Thu, 30 Mar 2017 14:32:56 +0800 From: Qu Wenruo To: CC: Subject: [PATCH v4 3/5] btrfs: scrub: Don't append on-disk pages for raid56 scrub Date: Thu, 30 Mar 2017 14:32:49 +0800 Message-ID: <20170330063251.16872-4-quwenruo@cn.fujitsu.com> X-Mailer: git-send-email 2.12.1 In-Reply-To: <20170330063251.16872-1-quwenruo@cn.fujitsu.com> References: <20170330063251.16872-1-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.34] X-yoursite-MailScanner-ID: ED56549F9A69.A1742 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: quwenruo@cn.fujitsu.com Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In the following situation, scrub will calculate wrong parity to overwrite correct one: RAID5 full stripe: Before | Dev 1 | Dev 2 | Dev 3 | | Data stripe 1 | Data stripe 2 | Parity Stripe | --------------------------------------------------- 0 | 0x0000 (Bad) | 0xcdcd | 0x0000 | --------------------------------------------------- 4K | 0xcdcd | 0xcdcd | 0x0000 | ... | 0xcdcd | 0xcdcd | 0x0000 | --------------------------------------------------- 64K After scrubbing dev3 only: | Dev 1 | Dev 2 | Dev 3 | | Data stripe 1 | Data stripe 2 | Parity Stripe | --------------------------------------------------- 0 | 0xcdcd (Good) | 0xcdcd | 0xcdcd (Bad) | --------------------------------------------------- 4K | 0xcdcd | 0xcdcd | 0x0000 | ... | 0xcdcd | 0xcdcd | 0x0000 | --------------------------------------------------- 64K The reason is after raid56 read rebuild rbio->stripe_pages are all correct recovered (0xcd for data stripes). However when we check and repair parity, in scrub_parity_check_and_repair(), we will append pages in sparity->spages list to rbio->bio_pages[], which contains old on-disk data. And when we submit parity data to disk, we calculate parity using rbio->bio_pages[] first, if rbio->bio_pages[] is not found, then fallback to rbio->stripe_pages[]. The patch fix it by not appending pages from sparity->spages. So finish_parity_scrub() will use rbio->stripe_pages[] which is correct. Signed-off-by: Qu Wenruo Reviewed-by: Liu Bo --- fs/btrfs/scrub.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 4bbefc96485d..bffbe3ce7d70 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3005,7 +3005,6 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity) struct btrfs_fs_info *fs_info = sctx->fs_info; struct bio *bio; struct btrfs_raid_bio *rbio; - struct scrub_page *spage; struct btrfs_bio *bbio = NULL; u64 length; int ret; @@ -3035,9 +3034,6 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity) if (!rbio) goto rbio_out; - list_for_each_entry(spage, &sparity->spages, list) - raid56_add_scrub_pages(rbio, spage->page, spage->logical); - scrub_pending_bio_inc(sctx); raid56_parity_submit_scrub_rbio(rbio); return;