From patchwork Tue Jan 13 12:34:45 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhaolei X-Patchwork-Id: 5620261 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 001DA9F3A0 for ; Tue, 13 Jan 2015 12:36:30 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F2DBB20608 for ; Tue, 13 Jan 2015 12:36:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEF5220605 for ; Tue, 13 Jan 2015 12:36:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752547AbbAMMgX (ORCPT ); Tue, 13 Jan 2015 07:36:23 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:19414 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752489AbbAMMgL (ORCPT ); Tue, 13 Jan 2015 07:36:11 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="55984213" Received: from unknown (HELO edo.cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 13 Jan 2015 20:32:42 +0800 Received: from G08CNEXCHPEKD03.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t0DCZXU5000518; Tue, 13 Jan 2015 20:35:33 +0800 Received: from localhost.localdomain (10.167.226.114) by G08CNEXCHPEKD03.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server id 14.3.181.6; Tue, 13 Jan 2015 20:36:10 +0800 From: Zhaolei To: CC: Zhao Lei , Miao Xie Subject: [PATCH 12/15] Btrfs: Combine per-page recover in dev-replace and scrub Date: Tue, 13 Jan 2015 20:34:45 +0800 Message-ID: <1421152488-30548-13-git-send-email-zhaolei@cn.fujitsu.com> X-Mailer: git-send-email 1.8.5.1 In-Reply-To: <1421152488-30548-1-git-send-email-zhaolei@cn.fujitsu.com> References: <1421152488-30548-1-git-send-email-zhaolei@cn.fujitsu.com> MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Zhao Lei The code are similar, combine them to make code clean and easy to maintenance. Some lost condition are also completed with benefit of this combination. Signed-off-by: Zhao Lei Signed-off-by: Miao Xie --- fs/btrfs/scrub.c | 110 ++++++++++++++++++++++++++++--------------------------- 1 file changed, 57 insertions(+), 53 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index d1d681f..000fa59 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -1099,19 +1099,47 @@ nodatasum_case: } } + /* + * In case of I/O errors in the area that is supposed to be + * repaired, continue by picking good copies of those pages. + * Select the good pages from mirrors to rewrite bad pages from + * the area to fix. Afterwards verify the checksum of the block + * that is supposed to be repaired. This verification step is + * only done for the purpose of statistic counting and for the + * final scrub report, whether errors remain. + * A perfect algorithm could make use of the checksum and try + * all possible combinations of pages from the different mirrors + * until the checksum verification succeeds. For example, when + * the 2nd page of mirror #1 faces I/O errors, and the 2nd page + * of mirror #2 is readable but the final checksum test fails, + * then the 2nd page of mirror #3 could be tried, whether now + * the final checksum succeedes. But this would be a rare + * exception and is therefore not implemented. At least it is + * avoided that the good copy is overwritten. + * A more useful improvement would be to pick the sectors + * without I/O error based on sector sizes (512 bytes on legacy + * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one + * mirror could be repaired by taking 512 byte of a different + * mirror, even if other 512 byte sectors in the same PAGE_SIZE + * area are unreadable. + */ + /* can only fix I/O errors from here on */ if (sblock_bad->no_io_error_seen) goto did_not_correct_error; - /* - * for dev_replace, pick good pages and write to the target device. - */ - if (sctx->is_dev_replace) { - success = 1; - for (page_num = 0; page_num < sblock_bad->page_count; - page_num++) { - struct scrub_block *sblock_other = NULL; + success = 1; + for (page_num = 0; page_num < sblock_bad->page_count; + page_num++) { + struct scrub_page *page_bad = sblock_bad->pagev[page_num]; + struct scrub_block *sblock_other = NULL; + /* skip no-io-error page in scrub */ + if (!page_bad->io_error && !sctx->is_dev_replace) + continue; + + /* try to find no-io-error page in mirrors */ + if (page_bad->io_error) { for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS && sblocks_for_recheck[mirror_index].page_count > 0; @@ -1123,18 +1151,20 @@ nodatasum_case: break; } } + if (!sblock_other) + success = 0; + } - if (!sblock_other) { - /* - * did not find a mirror to fetch the page - * from. scrub_write_page_to_dev_replace() - * handles this case (page->io_error), by - * filling the block with zeros before - * submitting the write request - */ + if (sctx->is_dev_replace) { + /* + * did not find a mirror to fetch the page + * from. scrub_write_page_to_dev_replace() + * handles this case (page->io_error), by + * filling the block with zeros before + * submitting the write request + */ + if (!sblock_other) sblock_other = sblock_bad; - success = 0; - } if (scrub_write_page_to_dev_replace(sblock_other, page_num) != 0) { @@ -1144,9 +1174,15 @@ nodatasum_case: num_write_errors); success = 0; } + } else if (sblock_other) { + ret = scrub_repair_page_from_good_copy(sblock_bad, + sblock_other, + page_num, 0); + if (0 == ret) + page_bad->io_error = 0; + else + success = 0; } - - goto out; } /* @@ -1175,39 +1211,7 @@ nodatasum_case: * area are unreadable. */ - success = 1; - for (page_num = 0; page_num < sblock_bad->page_count; page_num++) { - struct scrub_page *page_bad = sblock_bad->pagev[page_num]; - - if (!page_bad->io_error) - continue; - - for (mirror_index = 0; - mirror_index < BTRFS_MAX_MIRRORS && - sblocks_for_recheck[mirror_index].page_count > 0; - mirror_index++) { - struct scrub_block *sblock_other = sblocks_for_recheck + - mirror_index; - struct scrub_page *page_other = sblock_other->pagev[ - page_num]; - - if (!page_other->io_error) { - ret = scrub_repair_page_from_good_copy( - sblock_bad, sblock_other, page_num, 0); - if (0 == ret) { - page_bad->io_error = 0; - break; /* succeeded for this page */ - } - } - } - - if (page_bad->io_error) { - /* did not find a mirror to copy the page from */ - success = 0; - } - } - - if (success) { + if (success && !sctx->is_dev_replace) { if (is_metadata || have_csum) { /* * need to verify the checksum now that all