n_bytes += sizeof(yaffs_checkpt_dev_t);
n_bytes += dev_blocks * sizeof(yaffs_block_info_t);
n_bytes += dev_blocks * dev->chunk_bit_stride;
n_bytes += sizeof(yaffs_checkpt_dev_t);
n_bytes += dev_blocks * sizeof(yaffs_block_info_t);
n_bytes += dev_blocks * dev->chunk_bit_stride;