fat_get_cluster
ret = fat_get_cluster(inode, cluster, &fclus, &dclus);
extern int fat_get_cluster(struct inode *inode, int cluster,
ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);