From patchwork Fri Dec 28 03:42:36 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "jeff.liu" X-Patchwork-Id: 1914381 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 A20A83FC66 for ; Fri, 28 Dec 2012 03:43:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753169Ab2L1Dn2 (ORCPT ); Thu, 27 Dec 2012 22:43:28 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:16535 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753125Ab2L1Dn1 (ORCPT ); Thu, 27 Dec 2012 22:43:27 -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 qBS3gesn030125 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 28 Dec 2012 03:42:41 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 qBS3geMI006020 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 28 Dec 2012 03:42:40 GMT Received: from abhmt117.oracle.com (abhmt117.oracle.com [141.146.116.69]) by acsmt357.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id qBS3gehC022278; Thu, 27 Dec 2012 21:42:40 -0600 Received: from [192.168.1.103] (/114.248.197.53) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 27 Dec 2012 19:42:39 -0800 Message-ID: <50DD152C.4050701@oracle.com> Date: Fri, 28 Dec 2012 11:42:36 +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 v8 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 file system. Signed-off-by: Jie Liu Signed-off-by: Anand Jain Cc: Miao Xie Cc: Goffredo Baroncelli Cc: David Sterba --- fs/btrfs/ioctl.c | 22 ++++++++++++++++++++++ fs/btrfs/ioctl.h | 2 ++ 2 files changed, 24 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 8fcf9a5..4be5d15 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3699,6 +3699,26 @@ 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) { + len--; + WARN(1, "btrfs: device label is not zero terminated, " + "it will be truncated to %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 +3817,8 @@ 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