#val_type uint64_t
BTRFS_BALANCE_DATA              (1ULL << 0)
BTRFS_BALANCE_SYSTEM            (1ULL << 1)
BTRFS_BALANCE_METADATA          (1ULL << 2)
BTRFS_BALANCE_FORCE		(1ULL << 3)
BTRFS_BALANCE_RESUME		(1ULL << 4)