dblksize
block_size = dblksize(fs, &fp->f_di.i2, (u_int64_t)file_block);
block_size = dblksize(fs, &fp->f_di.i1, (u_int64_t)file_block);
block_size = dblksize(fs, &fp->f_di, (u_int64_t)file_block);
block_size = dblksize(fs, &fp->f_di, (u_int64_t)file_block);