btrfs_nr_parity_stripes
ASSERT(btrfs_nr_parity_stripes(bioc->map_type));
rbio->nr_data = real_stripes - btrfs_nr_parity_stripes(bioc->map_type);
return map->num_stripes - btrfs_nr_parity_stripes(map->type);
return bioc->num_stripes - btrfs_nr_parity_stripes(bioc->map_type);
int btrfs_nr_parity_stripes(u64 type);