From patchwork Fri Oct 28 02:31:40 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 9400909 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 987E260588 for ; Fri, 28 Oct 2016 02:33:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 855972A130 for ; Fri, 28 Oct 2016 02:33:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 79D1D2A113; Fri, 28 Oct 2016 02:33:03 +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 284272A0E3 for ; Fri, 28 Oct 2016 02:33:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1034333AbcJ1Cc7 (ORCPT ); Thu, 27 Oct 2016 22:32:59 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:48358 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1034324AbcJ1Cc6 (ORCPT ); Thu, 27 Oct 2016 22:32:58 -0400 X-IronPort-AV: E=Sophos;i="5.20,367,1444665600"; d="scan'208";a="932112" Received: from unknown (HELO cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 28 Oct 2016 10:32:04 +0800 Received: from adam-work.localdomain (unknown [10.167.226.34]) by cn.fujitsu.com (Postfix) with ESMTP id 52E5D41B4BC3; Fri, 28 Oct 2016 10:32:03 +0800 (CST) From: Qu Wenruo To: linux-btrfs@vger.kernel.org, dsterba@suse.cz Subject: [PATCH 04/19] btrfs-progs: raid56: Allow raid6 to recover data and p Date: Fri, 28 Oct 2016 10:31:40 +0800 Message-Id: <20161028023155.27336-5-quwenruo@cn.fujitsu.com> X-Mailer: git-send-email 2.10.1 In-Reply-To: <20161028023155.27336-1-quwenruo@cn.fujitsu.com> References: <20161028023155.27336-1-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 X-yoursite-MailScanner-ID: 52E5D41B4BC3.AD55A 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 Copied from kernel raid6 lib, with some naming modification. Signed-off-by: Qu Wenruo --- raid56.c | 36 ++++++++++++++++++++++++++++++++++++ raid56.h | 3 +++ 2 files changed, 39 insertions(+) diff --git a/raid56.c b/raid56.c index 599533e..3e471d6 100644 --- a/raid56.c +++ b/raid56.c @@ -233,3 +233,39 @@ int raid6_recov_data2(int nr_devs, size_t stripe_len, int dest1, int dest2, free(zero_mem2); return ret; } + +int raid6_recov_datap(int nr_devs, size_t stripe_len, int dest1, void **data) +{ + u8 *p, *q, *dq; + const u8 *qmul; /* Q multiplier table */ + char *zero_mem; + + p = (u8 *)data[nr_devs - 2]; + q = (u8 *)data[nr_devs - 1]; + + zero_mem = calloc(1, stripe_len); + if (!zero_mem) + return -ENOMEM; + + /* Compute syndrome with zero for the missing data page + Use the dead data page as temporary storage for delta q */ + dq = (u8 *)data[dest1]; + data[dest1] = (void *)zero_mem; + data[nr_devs - 1] = dq; + + raid6_gen_syndrome(nr_devs, stripe_len, data); + + /* Restore pointer table */ + data[dest1] = dq; + data[nr_devs - 1] = q; + + /* Now, pick the proper data tables */ + qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[dest1]]]; + + /* Now do it... */ + while ( stripe_len-- ) { + *p++ ^= *dq = qmul[*q ^ *dq]; + q++; dq++; + } + return 0; +} diff --git a/raid56.h b/raid56.h index 46fd3a9..e30cc28 100644 --- a/raid56.h +++ b/raid56.h @@ -19,6 +19,9 @@ void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs); int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data); +/* Recover data and P */ +int raid6_recov_datap(int nr_devs, size_t stripe_len, int dest1, void **data); + /* Recover 2 data */ int raid6_recov_data2(int nr_devs, size_t stripe_len, int dest1, int dest2, void **data);