On mon, 17 Dec 2012 19:22:02 +0800, Jeff Liu wrote:
> Introduce a new ioctl BTRFS_IOC_GET_FSLABEL to fetch the label of a mounted
> file system.
>
> Signed-off-by: Jie Liu <jeff....@oracle.com>
> Signed-off-by: Anand Jain <anand.j...@oracle.com>
> Cc: Miao Xie <mi...@cn.fujitsu.com>
Reviewed-by: Miao Xie <mi...@cn.fujitsu.com>
>
> ---
> fs/btrfs/ioctl.c | 15 +++++++++++++++
> fs/btrfs/ioctl.h | 2 ++
> 2 files changed, 17 insertions(+)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 8fcf9a5..6a2488a 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3699,6 +3699,19 @@ 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;
> + int ret;
> +
> + mutex_lock(&root->fs_info->volume_mutex);
> + ret = copy_to_user(arg, label, strlen(label));
> + 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 +3810,8 @@ 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
>
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