From patchwork Fri Jan 30 09:20:47 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 5748011 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 7A3CABF440 for ; Fri, 30 Jan 2015 09:23:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2B73D2013A for ; Fri, 30 Jan 2015 09:23:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B10392024D for ; Fri, 30 Jan 2015 09:23:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760192AbbA3JXP (ORCPT ); Fri, 30 Jan 2015 04:23:15 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:29041 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1759911AbbA3JXI (ORCPT ); Fri, 30 Jan 2015 04:23:08 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="56879839" Received: from unknown (HELO edo.cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 30 Jan 2015 17:19:27 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t0U9MGgg028841 for ; Fri, 30 Jan 2015 17:22:17 +0800 Received: from localhost.localdomain (10.167.226.33) by G08CNEXCHPEKD02.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.181.6; Fri, 30 Jan 2015 17:22:58 +0800 From: Qu Wenruo To: Subject: [PATCH v5 2/9] btrfs: Make btrfs_parse_options() parse mount option in a atomic way Date: Fri, 30 Jan 2015 17:20:47 +0800 Message-ID: <1422609654-19519-3-git-send-email-quwenruo@cn.fujitsu.com> X-Mailer: git-send-email 2.2.2 In-Reply-To: <1422609654-19519-1-git-send-email-quwenruo@cn.fujitsu.com> References: <1422609654-19519-1-git-send-email-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.33] 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 Current btrfs_parse_options() is not atomic, which can set and clear a bit, especially for nospace_cache case. For example, if a fs is mounted with nospace_cache, btrfs_parse_options() will set SPACE_CACHE bit first(since cache_generation is non-zeo) and clear the SPACE_CACHE bit due to nospace_cache mount option. So under heavy operations and remount a nospace_cache btrfs, there is a windows for commit to create space cache. This bug can be reproduced by fstest/btrfs/071 073 074 with nospace_cache mount option. It has about 50% chance to create space cache, and about 10% chance to create wrong space cache, which can't pass btrfsck. This patch will do the mount option parse in a copy-and-update method. First copy the mount_opt from fs_info to new_opt, and only update options in new_opt. At last, copy the new_opt back to fs_info->mount_opt. This patch is already good enough to fix the above nospace_cache + remount bug, but need later patch to make sure mount options does not change during transaction. Signed-off-by: Qu Wenruo --- changelog: v3: Newly introduced v4: None v5: Add ACCESS_ONE() macro to avoid aggressive compiler optimization to not read fs_info->mount_opt to new_opt but always use fs_info->mount_opt. --- fs/btrfs/ctree.h | 16 ++++---- fs/btrfs/super.c | 115 +++++++++++++++++++++++++++++-------------------------- 2 files changed, 69 insertions(+), 62 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 08741e8..0d44ea9 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2120,18 +2120,18 @@ struct btrfs_ioctl_defrag_range_args { #define btrfs_test_opt(root, opt) ((root)->fs_info->mount_opt & \ BTRFS_MOUNT_##opt) -#define btrfs_set_and_info(root, opt, fmt, args...) \ +#define btrfs_set_and_info(fs_info, val, opt, fmt, args...) \ { \ - if (!btrfs_test_opt(root, opt)) \ - btrfs_info(root->fs_info, fmt, ##args); \ - btrfs_set_opt(root->fs_info->mount_opt, opt); \ + if (!btrfs_raw_test_opt(val, opt)) \ + btrfs_info(fs_info, fmt, ##args); \ + btrfs_set_opt(val, opt); \ } -#define btrfs_clear_and_info(root, opt, fmt, args...) \ +#define btrfs_clear_and_info(fs_info, val, opt, fmt, args...) \ { \ - if (btrfs_test_opt(root, opt)) \ - btrfs_info(root->fs_info, fmt, ##args); \ - btrfs_clear_opt(root->fs_info->mount_opt, opt); \ + if (btrfs_raw_test_opt(val, opt)) \ + btrfs_info(fs_info, fmt, ##args); \ + btrfs_clear_opt(val, opt); \ } /* diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index b0c45b2..3ea3ce3 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -395,10 +395,13 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) int ret = 0; char *compress_type; bool compress_force = false; + unsigned long new_opt; + + new_opt = ACCESS_ONCE(info->mount_opt); cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy); if (cache_gen) - btrfs_set_opt(info->mount_opt, SPACE_CACHE); + btrfs_set_opt(new_opt, SPACE_CACHE); if (!options) goto out; @@ -422,7 +425,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) switch (token) { case Opt_degraded: btrfs_info(root->fs_info, "allowing degraded mounts"); - btrfs_set_opt(info->mount_opt, DEGRADED); + btrfs_set_opt(new_opt, DEGRADED); break; case Opt_subvol: case Opt_subvolid: @@ -434,7 +437,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) */ break; case Opt_nodatasum: - btrfs_set_and_info(root, NODATASUM, + btrfs_set_and_info(info, new_opt, NODATASUM, "setting nodatasum"); break; case Opt_datasum: @@ -444,8 +447,8 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) else btrfs_info(root->fs_info, "setting datasum"); } - btrfs_clear_opt(info->mount_opt, NODATACOW); - btrfs_clear_opt(info->mount_opt, NODATASUM); + btrfs_clear_opt(new_opt, NODATACOW); + btrfs_clear_opt(new_opt, NODATASUM); break; case Opt_nodatacow: if (!btrfs_test_opt(root, NODATACOW)) { @@ -457,13 +460,13 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) btrfs_info(root->fs_info, "setting nodatacow"); } } - btrfs_clear_opt(info->mount_opt, COMPRESS); - btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS); - btrfs_set_opt(info->mount_opt, NODATACOW); - btrfs_set_opt(info->mount_opt, NODATASUM); + btrfs_clear_opt(new_opt, COMPRESS); + btrfs_clear_opt(new_opt, FORCE_COMPRESS); + btrfs_set_opt(new_opt, NODATACOW); + btrfs_set_opt(new_opt, NODATASUM); break; case Opt_datacow: - btrfs_clear_and_info(root, NODATACOW, + btrfs_clear_and_info(info, new_opt, NODATACOW, "setting datacow"); break; case Opt_compress_force: @@ -477,20 +480,20 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) strcmp(args[0].from, "zlib") == 0) { compress_type = "zlib"; info->compress_type = BTRFS_COMPRESS_ZLIB; - btrfs_set_opt(info->mount_opt, COMPRESS); - btrfs_clear_opt(info->mount_opt, NODATACOW); - btrfs_clear_opt(info->mount_opt, NODATASUM); + btrfs_set_opt(new_opt, COMPRESS); + btrfs_clear_opt(new_opt, NODATACOW); + btrfs_clear_opt(new_opt, NODATASUM); } else if (strcmp(args[0].from, "lzo") == 0) { compress_type = "lzo"; info->compress_type = BTRFS_COMPRESS_LZO; - btrfs_set_opt(info->mount_opt, COMPRESS); - btrfs_clear_opt(info->mount_opt, NODATACOW); - btrfs_clear_opt(info->mount_opt, NODATASUM); + btrfs_set_opt(new_opt, COMPRESS); + btrfs_clear_opt(new_opt, NODATACOW); + btrfs_clear_opt(new_opt, NODATASUM); btrfs_set_fs_incompat(info, COMPRESS_LZO); } else if (strncmp(args[0].from, "no", 2) == 0) { compress_type = "no"; - btrfs_clear_opt(info->mount_opt, COMPRESS); - btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS); + btrfs_clear_opt(new_opt, COMPRESS); + btrfs_clear_opt(new_opt, FORCE_COMPRESS); compress_force = false; } else { ret = -EINVAL; @@ -498,7 +501,8 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) } if (compress_force) { - btrfs_set_and_info(root, FORCE_COMPRESS, + btrfs_set_and_info(info, new_opt, + FORCE_COMPRESS, "force %s compression", compress_type); } else { @@ -512,29 +516,29 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) * flag, otherwise, there is no way for users * to disable forcible compression separately. */ - btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS); + btrfs_clear_opt(new_opt, FORCE_COMPRESS); } break; case Opt_ssd: - btrfs_set_and_info(root, SSD, + btrfs_set_and_info(info, new_opt, SSD, "use ssd allocation scheme"); break; case Opt_ssd_spread: - btrfs_set_and_info(root, SSD_SPREAD, + btrfs_set_and_info(info, new_opt, SSD_SPREAD, "use spread ssd allocation scheme"); - btrfs_set_opt(info->mount_opt, SSD); + btrfs_set_opt(new_opt, SSD); break; case Opt_nossd: - btrfs_set_and_info(root, NOSSD, - "not using ssd allocation scheme"); - btrfs_clear_opt(info->mount_opt, SSD); + btrfs_set_and_info(info, new_opt, NOSSD, + "not using ssd allocation scheme"); + btrfs_clear_opt(new_opt, SSD); break; case Opt_barrier: - btrfs_clear_and_info(root, NOBARRIER, + btrfs_clear_and_info(info, new_opt, NOBARRIER, "turning on barriers"); break; case Opt_nobarrier: - btrfs_set_and_info(root, NOBARRIER, + btrfs_set_and_info(info, new_opt, NOBARRIER, "turning off barriers"); break; case Opt_thread_pool: @@ -594,19 +598,19 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) root->fs_info->sb->s_flags &= ~MS_POSIXACL; break; case Opt_notreelog: - btrfs_set_and_info(root, NOTREELOG, + btrfs_set_and_info(info, new_opt, NOTREELOG, "disabling tree log"); break; case Opt_treelog: - btrfs_clear_and_info(root, NOTREELOG, + btrfs_clear_and_info(info, new_opt, NOTREELOG, "enabling tree log"); break; case Opt_flushoncommit: - btrfs_set_and_info(root, FLUSHONCOMMIT, + btrfs_set_and_info(info, new_opt, FLUSHONCOMMIT, "turning on flush-on-commit"); break; case Opt_noflushoncommit: - btrfs_clear_and_info(root, FLUSHONCOMMIT, + btrfs_clear_and_info(info, new_opt, FLUSHONCOMMIT, "turning off flush-on-commit"); break; case Opt_ratio: @@ -623,71 +627,71 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) } break; case Opt_discard: - btrfs_set_and_info(root, DISCARD, + btrfs_set_and_info(info, new_opt, DISCARD, "turning on discard"); break; case Opt_nodiscard: - btrfs_clear_and_info(root, DISCARD, + btrfs_clear_and_info(info, new_opt, DISCARD, "turning off discard"); break; case Opt_space_cache: - btrfs_set_and_info(root, SPACE_CACHE, + btrfs_set_and_info(info, new_opt, SPACE_CACHE, "enabling disk space caching"); break; case Opt_rescan_uuid_tree: - btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE); + btrfs_set_opt(new_opt, RESCAN_UUID_TREE); break; case Opt_no_space_cache: - btrfs_clear_and_info(root, SPACE_CACHE, + btrfs_clear_and_info(info, new_opt, SPACE_CACHE, "disabling disk space caching"); break; case Opt_inode_cache: - btrfs_set_pending_and_info(info, INODE_MAP_CACHE, + btrfs_set_and_info(info, new_opt, INODE_MAP_CACHE, "enabling inode map caching"); break; case Opt_noinode_cache: - btrfs_clear_pending_and_info(info, INODE_MAP_CACHE, + btrfs_clear_and_info(info, new_opt, INODE_MAP_CACHE, "disabling inode map caching"); break; case Opt_clear_cache: - btrfs_set_and_info(root, CLEAR_CACHE, + btrfs_set_and_info(info, new_opt, CLEAR_CACHE, "force clearing of disk cache"); break; case Opt_user_subvol_rm_allowed: - btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED); + btrfs_set_opt(new_opt, USER_SUBVOL_RM_ALLOWED); break; case Opt_enospc_debug: - btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG); + btrfs_set_opt(new_opt, ENOSPC_DEBUG); break; case Opt_noenospc_debug: - btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG); + btrfs_clear_opt(new_opt, ENOSPC_DEBUG); break; case Opt_defrag: - btrfs_set_and_info(root, AUTO_DEFRAG, + btrfs_set_and_info(info, new_opt, AUTO_DEFRAG, "enabling auto defrag"); break; case Opt_nodefrag: - btrfs_clear_and_info(root, AUTO_DEFRAG, + btrfs_clear_and_info(info, new_opt, AUTO_DEFRAG, "disabling auto defrag"); break; case Opt_recovery: btrfs_info(root->fs_info, "enabling auto recovery"); - btrfs_set_opt(info->mount_opt, RECOVERY); + btrfs_set_opt(new_opt, RECOVERY); break; case Opt_skip_balance: - btrfs_set_opt(info->mount_opt, SKIP_BALANCE); + btrfs_set_opt(new_opt, SKIP_BALANCE); break; #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY case Opt_check_integrity_including_extent_data: btrfs_info(root->fs_info, "enabling check integrity including extent data"); - btrfs_set_opt(info->mount_opt, + btrfs_set_opt(new_opt, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA); - btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); + btrfs_set_opt(new_opt, CHECK_INTEGRITY); break; case Opt_check_integrity: btrfs_info(root->fs_info, "enabling check integrity"); - btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY); + btrfs_set_opt(new_opt, CHECK_INTEGRITY); break; case Opt_check_integrity_print_mask: ret = match_int(&args[0], &intarg); @@ -713,10 +717,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) #endif case Opt_fatal_errors: if (strcmp(args[0].from, "panic") == 0) - btrfs_set_opt(info->mount_opt, + btrfs_set_opt(new_opt, PANIC_ON_FATAL_ERROR); else if (strcmp(args[0].from, "bug") == 0) - btrfs_clear_opt(info->mount_opt, + btrfs_clear_opt(new_opt, PANIC_ON_FATAL_ERROR); else { ret = -EINVAL; @@ -752,8 +756,11 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) } } out: - if (!ret && btrfs_test_opt(root, SPACE_CACHE)) - btrfs_info(root->fs_info, "disk space caching is enabled"); + if (!ret) { + if (btrfs_raw_test_opt(new_opt, SPACE_CACHE)) + btrfs_info(info, "disk space caching is enabled"); + ACCESS_ONCE(info->mount_opt) = new_opt; + } kfree(orig); return ret; }