fs_old_nrpos
int32_t fs_old_nrpos; /* number of rotational positions */
n->fs_old_nrpos = bswap32(o->fs_old_nrpos);
for (i = 0; i < fs->fs_old_cpg * fs->fs_old_nrpos; i++)
sblock.fs_old_nrpos = 1;