+extern int zfs_hold(zfs_handle_t *, const char *, const char *, boolean_t,
+ boolean_t, boolean_t);
+extern int zfs_hold_range(zfs_handle_t *, const char *, const char *,
+ const char *, boolean_t, boolean_t, snapfilter_cb_t, void *);
+extern int zfs_release(zfs_handle_t *, const char *, const char *, boolean_t);
+extern int zfs_release_range(zfs_handle_t *, const char *, const char *,
+ const char *, boolean_t);
+extern uint64_t zvol_volsize_to_reservation(uint64_t, nvlist_t *);
+
+typedef int (*zfs_userspace_cb_t)(void *arg, const char *domain,
+ uid_t rid, uint64_t space);
+
+extern int zfs_userspace(zfs_handle_t *zhp, zfs_userquota_prop_t type,
+ zfs_userspace_cb_t func, void *arg);