POWEROF2
if (!POWEROF2(sblock.fs_bsize) || sblock.fs_bsize < MINBSIZE ||
if (!POWEROF2(sblock.fs_fsize) || sblock.fs_fsize > sblock.fs_bsize ||
if (!POWEROF2(bsize)) {
if (!POWEROF2(fsize)) {
if (!POWEROF2(sblock.fs_bsize)) {
if (!POWEROF2(sblock.fs_fsize)) {
if (maxbsize < bsize || !POWEROF2(maxbsize)) {