Re: [PATCH V4 2/2] Btrfs: Add a new ioctl to change the label of a mounted filesystem

[Miao Xie <miaox@cn.fujitsu.com>]

Hi, Liu

On wed, 12 Dec 2012 08:22:28 +0800, Jeff Liu wrote:
> Add a new ioctl BTRFS_FS_SETLABEL to change the label of a mounted filesystem.
> 
> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> 
> ---
>  fs/btrfs/ioctl.c |   14 ++++++++++++++
>  fs/btrfs/ioctl.h |    2 ++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 8fcf9a5..b0a5e17 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3699,6 +3699,18 @@ out:
>  	return ret;
>  }
>  
> +static int btrfs_ioctl_get_fslabel(struct btrfs_root *root, void __user *arg)
> +{
> +	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;
> +}


You sent out a wrong patch.

Thanks
Miao

> +
>  long btrfs_ioctl(struct file *file, unsigned int
>  		cmd, unsigned long arg)
>  {
> @@ -3797,6 +3809,8 @@ 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(root, argp);
>  	}
>  
>  	return -ENOTTY;
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 731e287..98f896f 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -453,4 +453,6 @@ struct btrfs_ioctl_send_args {
>  			       struct btrfs_ioctl_qgroup_limit_args)
>  #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \
>  				      struct btrfs_ioctl_get_dev_stats)
> +#define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 53, \
> +				   char[BTRFS_LABEL_SIZE])
>  #endif
>