CGSIZE_IF
cgzero = CGSIZE_IF(&sblock, 0, 0);
cgall = CGSIZE_IF(&sblock, inodeblks * FFS_INOPB(&sblock), sblock.fs_size);
i = CGSIZE_IF(&sblock, inodes_per_cg, sblock.fs_fpg);
#define CGSIZE(fs) CGSIZE_IF((fs), (fs)->fs_ipg, (fs)->fs_fpg)