fs/btrfs/ioctl.h

#ifndef __IOCTL_
#define __IOCTL_
#include <linux/ioctl.h>

#define BTRFS_IOCTL_MAGIC 0x94
#define BTRFS_VOL_NAME_MAX 255
struct btrfs_ioctl_vol_args {
	char name[BTRFS_VOL_NAME_MAX + 1];
};

#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
				   struct btrfs_ioctl_vol_args)
#define BTRFS_IOC_ADD_DISK _IOW(BTRFS_IOCTL_MAGIC, 2, \
				   struct btrfs_ioctl_vol_args)
#endif