ffs_clrblock     1386 ufs/ffs/ffs_alloc.c 	ffs_clrblock(fs, blksfree, (long) blkno);
ffs_clrblock      132 ufs/ffs/ffs_extern.h void ffs_clrblock(struct fs *, u_char *, daddr_t);
ffs_clrblock       86 ufs/ffs/ffs_subr.c void	ffs_clrblock(struct fs *, u_char *, daddr_t);