From patchwork Mon Feb 16 01:02:05 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 5830961 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 427F4BF440 for ; Mon, 16 Feb 2015 01:02:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5BDA920154 for ; Mon, 16 Feb 2015 01:02:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4ADE4200F0 for ; Mon, 16 Feb 2015 01:02:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752059AbbBPBCJ (ORCPT ); Sun, 15 Feb 2015 20:02:09 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:57059 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751446AbbBPBCI (ORCPT ); Sun, 15 Feb 2015 20:02:08 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="57635429" Received: from unknown (HELO edo.cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 16 Feb 2015 08:58:31 +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 t1G11Ho7022687 for ; Mon, 16 Feb 2015 09:01:17 +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; Mon, 16 Feb 2015 09:02:08 +0800 From: Qu Wenruo To: Subject: [PATCH v9 9/9] btrfs: Use sb_want_write() to protect sysfs feature change. Date: Mon, 16 Feb 2015 09:02:05 +0800 Message-ID: <1424048525-26274-1-git-send-email-quwenruo@cn.fujitsu.com> X-Mailer: git-send-email 2.3.0 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 Just like label change, use sb_want_write() to do a correct protection. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba --- v4: Newly introduced. v5: Change to sb_want_write(). v6: Move sb_want_write() to the beginning of the function. v7: None v8: Move sb_want_write() after get fs_info. v9: Fix a unpaired sb_drop_write() in error handler. --- fs/btrfs/sysfs.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 7e548f7..19876ba 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -121,10 +121,14 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj, if (!fs_info) return -EPERM; - ret = kstrtoul(skip_spaces(buf), 0, &val); + ret = sb_want_write(fs_info->sb); if (ret) return ret; + ret = kstrtoul(skip_spaces(buf), 0, &val); + if (ret) + goto out; + if (fa->feature_set == FEAT_COMPAT) { set = BTRFS_FEATURE_COMPAT_SAFE_SET; clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR; @@ -141,22 +145,25 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj, /* Nothing to do */ if ((val && (features & fa->feature_bit)) || (!val && !(features & fa->feature_bit))) - return count; + goto out; if ((val && !(set & fa->feature_bit)) || (!val && !(clear & fa->feature_bit))) { btrfs_info(fs_info, "%sabling feature %s on mounted fs is not supported.", val ? "En" : "Dis", fa->kobj_attr.attr.name); - return -EPERM; + ret = -EPERM; + goto out; } btrfs_info(fs_info, "%s %s feature flag", val ? "Setting" : "Clearing", fa->kobj_attr.attr.name); trans = btrfs_start_transaction(fs_info->fs_root, 0); - if (IS_ERR(trans)) - return PTR_ERR(trans); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out; + } spin_lock(&fs_info->super_lock); features = get_features(fs_info, fa->feature_set); @@ -168,10 +175,12 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj, spin_unlock(&fs_info->super_lock); ret = btrfs_commit_transaction(trans, fs_info->fs_root); - if (ret) - return ret; - return count; +out: + sb_drop_write(fs_info->sb); + if (!ret) + return count; + return ret; } static umode_t btrfs_feature_visible(struct kobject *kobj,