+ * inputs:
+ * zc_guid flags (ZEVENT_NONBLOCK)
+ *
+ * outputs:
+ * zc_nvlist_dst next nvlist event
+ * zc_cookie dropped events since last get
+ * zc_cleanup_fd cleanup-on-exit file descriptor
+ */
+static int
+zfs_ioc_events_next(zfs_cmd_t *zc)
+{
+ zfs_zevent_t *ze;
+ nvlist_t *event = NULL;
+ minor_t minor;
+ uint64_t dropped = 0;
+ int error;
+
+ error = zfs_zevent_fd_hold(zc->zc_cleanup_fd, &minor, &ze);
+ if (error != 0)
+ return (error);
+
+ do {
+ error = zfs_zevent_next(ze, &event,
+ &zc->zc_nvlist_dst_size, &dropped);
+ if (event != NULL) {
+ zc->zc_cookie = dropped;
+ error = put_nvlist(zc, event);
+ nvlist_free(event);
+ }
+
+ if (zc->zc_guid & ZEVENT_NONBLOCK)
+ break;
+
+ if ((error == 0) || (error != ENOENT))
+ break;
+
+ error = zfs_zevent_wait(ze);
+ if (error)
+ break;
+ } while (1);
+
+ zfs_zevent_fd_rele(zc->zc_cleanup_fd);
+
+ return (error);
+}
+
+/*
+ * outputs:
+ * zc_cookie cleared events count
+ */
+static int
+zfs_ioc_events_clear(zfs_cmd_t *zc)
+{
+ int count;
+
+ zfs_zevent_drain_all(&count);
+ zc->zc_cookie = count;
+
+ return 0;
+}
+
+/*
+ * inputs:
+ * zc_name name of new filesystem or snapshot
+ * zc_value full name of old snapshot
+ *
+ * outputs:
+ * zc_cookie space in bytes
+ * zc_objset_type compressed space in bytes
+ * zc_perm_action uncompressed space in bytes
+ */
+static int
+zfs_ioc_space_written(zfs_cmd_t *zc)
+{
+ int error;
+ dsl_dataset_t *new, *old;
+
+ error = dsl_dataset_hold(zc->zc_name, FTAG, &new);
+ if (error != 0)
+ return (error);
+ error = dsl_dataset_hold(zc->zc_value, FTAG, &old);
+ if (error != 0) {
+ dsl_dataset_rele(new, FTAG);
+ return (error);
+ }
+
+ error = dsl_dataset_space_written(old, new, &zc->zc_cookie,
+ &zc->zc_objset_type, &zc->zc_perm_action);
+ dsl_dataset_rele(old, FTAG);
+ dsl_dataset_rele(new, FTAG);
+ return (error);
+}
+
+/*
+ * inputs:
+ * zc_name full name of last snapshot
+ * zc_value full name of first snapshot
+ *
+ * outputs:
+ * zc_cookie space in bytes
+ * zc_objset_type compressed space in bytes
+ * zc_perm_action uncompressed space in bytes
+ */
+static int
+zfs_ioc_space_snaps(zfs_cmd_t *zc)
+{
+ int error;
+ dsl_dataset_t *new, *old;
+
+ error = dsl_dataset_hold(zc->zc_name, FTAG, &new);
+ if (error != 0)
+ return (error);
+ error = dsl_dataset_hold(zc->zc_value, FTAG, &old);
+ if (error != 0) {
+ dsl_dataset_rele(new, FTAG);
+ return (error);
+ }
+
+ error = dsl_dataset_space_wouldfree(old, new, &zc->zc_cookie,
+ &zc->zc_objset_type, &zc->zc_perm_action);
+ dsl_dataset_rele(old, FTAG);
+ dsl_dataset_rele(new, FTAG);
+ return (error);
+}
+
+/*