extern int volume_id_probe_xfs(struct volume_id *id, uint64_t off);
extern int volume_id_probe_squashfs(struct volume_id *id, uint64_t off);
extern int volume_id_probe_netware(struct volume_id *id, uint64_t off);
extern int volume_id_probe_xfs(struct volume_id *id, uint64_t off);
extern int volume_id_probe_squashfs(struct volume_id *id, uint64_t off);
extern int volume_id_probe_netware(struct volume_id *id, uint64_t off);