fs_postbl
if (fs_postbl(&afs, c)[i] == -1)
for (j = fs_postbl(&afs, c)[i], k = 1; ;
fs_postbl(&afs, i % afs.fs_cpc)[j] == -1)
fs_postbl(&sblock, cylno)[rpos] = -1;
if (fs_postbl(&sblock, cylno)[rpos] == -1)
fs_postbl(&sblock, cylno)[rpos] - blk;
fs_postbl(&sblock, cylno)[rpos] = blk;
if (fs_postbl(fs, pos)[i] == -1) {
for (i = fs_postbl(fs, pos)[i];; ) {