blkoff
#define blkoff(fs, b) (secbyt(fs, (fs)->lsndta) + \
#define blkoff(fs, loc) /* loc % bsize */ \
#define blkoff(imp, loc) ((loc) & (imp)->im_bmask)
#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \
#define blkoff(udfmp, loc) ((loc) & (udfmp)->bmask)
#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \