ufs_fragnum
if (count + ufs_fragnum(fragment) > uspi->s_fpb) {
count = uspi->s_fpb - ufs_fragnum(fragment);
oldcount = ufs_fragnum (fragment);
if ((ufs_fragnum (fragment) + newcount) > uspi->s_fpb)
fragoff = ufs_fragnum (fragno);
if (ufs_fragnum(fragment) + count > uspi->s_fpb)
end = uspi->s_fpb - ufs_fragnum(lastfrag) - 1;
old_tail = ufs_fragnum(old_frags);
new_tail = ufs_fragnum(new_frags);