LOG_MINBSIZE
sblock.e2fs_bshift = LOG_MINBSIZE + sblock.e2fs.e2fs_log_bsize;
fs->e2fs_bshift = LOG_MINBSIZE + fs->e2fs.e2fs_log_bsize;
sblock.e2fs.e2fs_log_bsize = ilog2(bsize) - LOG_MINBSIZE;
sblock.e2fs_bshift = sblock.e2fs.e2fs_log_bsize + LOG_MINBSIZE;
#define MINBSIZE (1 << LOG_MINBSIZE)
fs->e2fs_bshift = LOG_MINBSIZE + fs->e2fs.e2fs_log_bsize;