From patchwork Sat Jan 5 02:48:01 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "jeff.liu" X-Patchwork-Id: 1935611 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 977633FDDA for ; Sat, 5 Jan 2013 02:49:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755731Ab3AECs5 (ORCPT ); Fri, 4 Jan 2013 21:48:57 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:48221 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755715Ab3AECsz (ORCPT ); Fri, 4 Jan 2013 21:48:55 -0500 Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by aserp1040.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id r052m6Ms024159 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 5 Jan 2013 02:48:06 GMT Received: from acsmt357.oracle.com (acsmt357.oracle.com [141.146.40.157]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id r052m5PV017562 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 5 Jan 2013 02:48:06 GMT Received: from abhmt105.oracle.com (abhmt105.oracle.com [141.146.116.57]) by acsmt357.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id r052m5UQ025452; Fri, 4 Jan 2013 20:48:05 -0600 Received: from [192.168.1.103] (/114.248.192.132) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 04 Jan 2013 18:48:05 -0800 Message-ID: <50E79461.3090802@oracle.com> Date: Sat, 05 Jan 2013 10:48:01 +0800 From: Jeff Liu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121028 Thunderbird/16.0.2 MIME-Version: 1.0 To: linux-btrfs@vger.kernel.org CC: anand.jain@oracle.com, miaox@cn.fujitsu.com, Goffredo Baroncelli , dsterba@suse.cz Subject: [RFC PATCH v9 1/2] Btrfs: Add a new ioctl to get the label of a mounted file system X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Add a new ioctl(2) BTRFS_IOC_GET_FSLABLE, so that we can get the label upon a mounted filesystem. Signed-off-by: Jie Liu Signed-off-by: Anand Jain Cc: Miao Xie Cc: Goffredo Baroncelli Cc: David Sterba --- fs/btrfs/ioctl.c | 21 +++++++++++++++++++++ fs/btrfs/ioctl.h | 2 ++ 2 files changed, 23 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 8fcf9a5..ef2f55a 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3699,6 +3699,25 @@ out: return ret; } +static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg) +{ + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; + const char *label = root->fs_info->super_copy->label; + size_t len = strnlen(label, BTRFS_LABEL_SIZE); + int ret; + + if (len == BTRFS_LABEL_SIZE) { + pr_warn("btrfs: label is too long, return the first %zu bytes\n", + --len); + } + + mutex_lock(&root->fs_info->volume_mutex); + ret = copy_to_user(arg, label, len); + mutex_unlock(&root->fs_info->volume_mutex); + + return ret ? -EFAULT : 0; +} + long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -3797,6 +3816,8 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_qgroup_create(root, argp); case BTRFS_IOC_QGROUP_LIMIT: return btrfs_ioctl_qgroup_limit(root, argp); + case BTRFS_IOC_GET_FSLABEL: + return btrfs_ioctl_get_fslabel(file, argp); } return -ENOTTY; diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h index 731e287..5b2cbef 100644 --- a/fs/btrfs/ioctl.h +++ b/fs/btrfs/ioctl.h @@ -451,6 +451,8 @@ struct btrfs_ioctl_send_args { struct btrfs_ioctl_qgroup_create_args) #define BTRFS_IOC_QGROUP_LIMIT _IOR(BTRFS_IOCTL_MAGIC, 43, \ struct btrfs_ioctl_qgroup_limit_args) +#define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 49, \ + char[BTRFS_LABEL_SIZE]) #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \ struct btrfs_ioctl_get_dev_stats) #endif