firstpg
if (page + psize <= firstpg(blk))
firstpg(blk) = page;
for (page = firstpg(blk); page <= lastpg(blk); page++, idx++) {
for (page = firstpg(blk); page <= lastpg(blk); page++,
for (page = firstpg(blk); page <= lastpg(blk); page++)