From patchwork Mon Dec 17 11:34:59 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "jeff.liu" X-Patchwork-Id: 1886701 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 6BC9A3FCA5 for ; Mon, 17 Dec 2012 11:35:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752202Ab2LQLfH (ORCPT ); Mon, 17 Dec 2012 06:35:07 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:30883 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751935Ab2LQLfG (ORCPT ); Mon, 17 Dec 2012 06:35:06 -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 qBHBZ4hO008810 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 17 Dec 2012 11:35:05 GMT Received: from acsmt356.oracle.com (acsmt356.oracle.com [141.146.40.156]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id qBHBZ4V7014174 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 17 Dec 2012 11:35:04 GMT Received: from abhmt112.oracle.com (abhmt112.oracle.com [141.146.116.64]) by acsmt356.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id qBHBZ3X8008883 for ; Mon, 17 Dec 2012 05:35:03 -0600 Received: from [10.191.9.229] (/10.191.9.229) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 17 Dec 2012 03:35:03 -0800 Message-ID: <50CF0363.9050900@oracle.com> Date: Mon, 17 Dec 2012 19:34:59 +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 Subject: [PATCH v5 1/4] Btrfs-progs: get 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 With this new ioctl(2), we can get the label for a mounted file system. It still does normal process to fetch label if the specified file system is unmounted. Signed-off-by: Jie Liu Signed-off-by: Anand Jain --- btrfslabel.c | 74 ++++++++++++++++++++++++++++++++++++++-------------------- ioctl.h | 2 ++ utils.c | 2 +- utils.h | 1 + 4 files changed, 53 insertions(+), 26 deletions(-) diff --git a/btrfslabel.c b/btrfslabel.c index cb142b0..443eff6 100644 --- a/btrfslabel.c +++ b/btrfslabel.c @@ -67,45 +67,69 @@ static void change_label_unmounted(char *dev, char *nLabel) close_ctree(root); } -int get_label_unmounted(char *dev) +static int get_label_unmounted(const char *dev) { - struct btrfs_root *root; + struct btrfs_root *root; + int ret; - /* Open the super_block at the default location - * and as read-only. - */ - root = open_ctree(dev, 0, 0); + ret = check_mounted(dev); + if (ret < 0) { + fprintf(stderr, "FATAL: error checking %s mount status\n", dev); + return -1; + } + if (ret > 0) { + fprintf(stderr, "ERROR: dev %s is mounted, use mount point\n", + dev); + return -1; + } - if(!root) - return -1; + /* Open the super_block at the default location + * and as read-only. + */ + root = open_ctree(dev, 0, 0); + if(!root) + return -1; - fprintf(stdout, "%s\n", root->fs_info->super_copy.label); + fprintf(stdout, "%s\n", root->fs_info->super_copy.label); - /* Now we close it since we are done. */ - close_ctree(root); - return 0; + /* Now we close it since we are done. */ + close_ctree(root); + return 0; } -int get_label(char *btrfs_dev) +/* + * If a partition is mounted, try to get the filesystem label via its + * mounted path rather than device. Return the corresponding error + * the user specified the device path. + */ +static int get_label_mounted(const char *mount_path) { + char label[BTRFS_LABEL_SIZE]; + int fd; - int ret; - ret = check_mounted(btrfs_dev); - if (ret < 0) - { - fprintf(stderr, "FATAL: error checking %s mount status\n", btrfs_dev); - return -1; + fd = open(mount_path, O_RDONLY | O_NOATIME); + if (fd < 0) { + fprintf(stderr, "ERROR: unable access to '%s'\n", mount_path); + return -1; } - if(ret != 0) - { - fprintf(stderr, "FATAL: the filesystem has to be unmounted\n"); - return -2; + memset(label, '\0', sizeof(label)); + if (ioctl(fd, BTRFS_IOC_GET_FSLABEL, label) < 0) { + fprintf(stderr, "ERROR: unable get label %s\n", strerror(errno)); + close(fd); + return -1; } - ret = get_label_unmounted(btrfs_dev); - return ret; + + fprintf(stdout, "%s\n", label); + return 0; } +int get_label(const char *btrfs_dev) +{ + return is_existing_blk_or_reg_file(btrfs_dev) ? + get_label_unmounted(btrfs_dev) : + get_label_mounted(btrfs_dev); +} int set_label(char *btrfs_dev, char *nLabel) { diff --git a/ioctl.h b/ioctl.h index 6fda3a1..0807b05 100644 --- a/ioctl.h +++ b/ioctl.h @@ -432,4 +432,6 @@ struct btrfs_ioctl_clone_range_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]) #endif diff --git a/utils.c b/utils.c index 205e667..d59bca3 100644 --- a/utils.c +++ b/utils.c @@ -811,7 +811,7 @@ int check_mounted(const char* file) return -errno; } - ret = check_mounted_where(fd, file, NULL, 0, NULL); + ret = check_mounted_where(fd, file, NULL, 0, NULL); close(fd); return ret; diff --git a/utils.h b/utils.h index 3a0368b..8750f28 100644 --- a/utils.h +++ b/utils.h @@ -46,4 +46,5 @@ int check_label(char *input); int get_mountpt(char *dev, char *mntpt, size_t size); int btrfs_scan_block_devices(int run_ioctl); +int is_existing_blk_or_reg_file(const char* filename); #endif