+/*
+ * Cylinder group block for a file system.
+ */
+#define CG_MAGIC 0x090255
+struct cg {
+ struct cg *cg_link; /* linked list of cyl groups */
+ long cg_magic; /* magic number */
+ time_t cg_time; /* time last written */
+ long cg_cgx; /* we are the cgx'th cylinder group */
+ short cg_ncyl; /* number of cyl's this cg */
+ short cg_niblk; /* number of inode blocks this cg */
+ long cg_ndblk; /* number of data blocks this cg */
+ struct csum cg_cs; /* cylinder summary information */
+ long cg_rotor; /* position of last used block */
+ long cg_frotor; /* position of last used frag */
+ long cg_irotor; /* position of last used inode */
+ long cg_frsum[MAXFRAG]; /* counts of available frags */
+ long cg_btotoff; /* (long) block totals per cylinder */
+ long cg_boff; /* (short) free block positions */
+ long cg_iusedoff; /* (char) used inode map */
+ long cg_freeoff; /* (u_char) free block map */
+ long cg_nextfreeoff; /* (u_char) next available space */
+ long cg_clustersumoff; /* (long) counts of avail clusters */
+ long cg_clusteroff; /* (char) free cluster map */
+ long cg_nclusterblks; /* number of clusters this cg */
+ long cg_sparecon[13]; /* reserved for future use */
+ u_char cg_space[1]; /* space for cylinder group maps */
+/* actually longer */
+};
+/*
+ * Macros for access to cylinder group array structures
+ */
+#define cg_blktot(cgp) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_btot) \
+ : ((long *)((char *)(cgp) + (cgp)->cg_btotoff)))
+#define cg_blks(fs, cgp, cylno) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_b[cylno]) \
+ : ((short *)((char *)(cgp) + (cgp)->cg_boff) + (cylno) * (fs)->fs_nrpos))
+#define cg_inosused(cgp) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_iused) \
+ : ((char *)((char *)(cgp) + (cgp)->cg_iusedoff)))
+#define cg_blksfree(cgp) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_free) \
+ : ((u_char *)((char *)(cgp) + (cgp)->cg_freeoff)))
+#define cg_chkmagic(cgp) \
+ ((cgp)->cg_magic == CG_MAGIC || ((struct ocg *)(cgp))->cg_magic == CG_MAGIC)
+#define cg_clustersfree(cgp) \
+ ((u_char *)((char *)(cgp) + (cgp)->cg_clusteroff))
+#define cg_clustersum(cgp) \
+ ((long *)((char *)(cgp) + (cgp)->cg_clustersumoff))