SINGLE
for (i = SINGLE; i < level; i++)
if (level > SINGLE) {
if (level > SINGLE && lastbn >= 0) {
lastiblock[SINGLE] = lastblock - NDADDR;
lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
for (level = TRIPLE; level >= SINGLE; level--)
for (level = TRIPLE; level >= SINGLE; level--) {
for (level = SINGLE; level <= TRIPLE; level++)