From patchwork Fri Jan 30 09:20:53 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 5748031 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 014069F358 for ; Fri, 30 Jan 2015 09:23:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3F9E82013A for ; Fri, 30 Jan 2015 09:23:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 011882025B for ; Fri, 30 Jan 2015 09:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760253AbbA3JXT (ORCPT ); Fri, 30 Jan 2015 04:23:19 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:60688 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1760128AbbA3JXN (ORCPT ); Fri, 30 Jan 2015 04:23:13 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="56879849" Received: from unknown (HELO edo.cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 30 Jan 2015 17:19:32 +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 t0U9ML0C028864 for ; Fri, 30 Jan 2015 17:22:21 +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 17:23:03 +0800 From: Qu Wenruo To: Subject: [PATCH v5 8/9] btrfs: Use sb_want_write() to protect label change. Date: Fri, 30 Jan 2015 17:20:53 +0800 Message-ID: <1422609654-19519-9-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 Use the new vfs API sb_want_write() to do the write protection of the label change transaction. Signed-off-by: Qu Wenruo --- v4: Newly introduced. v5: Change to use sb_want_write(). --- fs/btrfs/sysfs.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index b2e7bb4..3218245 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -25,6 +25,7 @@ #include #include #include +#include #include "ctree.h" #include "disk-io.h" @@ -377,8 +378,6 @@ static ssize_t btrfs_label_store(struct kobject *kobj, int ret; size_t p_len; - if (fs_info->sb->s_flags & MS_RDONLY) - return -EROFS; /* * p_len is the len until the first occurrence of either @@ -389,9 +388,15 @@ static ssize_t btrfs_label_store(struct kobject *kobj, if (p_len >= BTRFS_LABEL_SIZE) return -EINVAL; + ret = sb_want_write(fs_info->sb); + if (ret) + return ret; + trans = btrfs_start_transaction(root, 0); - if (IS_ERR(trans)) - return PTR_ERR(trans); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out; + } spin_lock(&root->fs_info->super_lock); memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE); @@ -399,9 +404,10 @@ static ssize_t btrfs_label_store(struct kobject *kobj, spin_unlock(&root->fs_info->super_lock); ret = btrfs_commit_transaction(trans, root); +out: + sb_drop_write(fs_info->sb); if (!ret) return len; - return ret; } BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);