ufs_cgstart
#define ufs_cgsblock(c) (ufs_cgstart(c) + uspi->s_sblkno) /* super blk */
#define ufs_cgcmin(c) (ufs_cgstart(c) + uspi->s_cblkno) /* cg block */
#define ufs_cgimin(c) (ufs_cgstart(c) + uspi->s_iblkno) /* inode blk */
#define ufs_cgdmin(c) (ufs_cgstart(c) + uspi->s_dblkno) /* 1st data */