+ last = plp;
+ while (*last != NULL)
+ last = &(*last)->pl_next;
+
+ if ((*plp)->pl_all)
+ features = zpool_get_features(zhp);
+
+ if ((*plp)->pl_all && firstexpand) {
+ for (i = 0; i < SPA_FEATURES; i++) {
+ zprop_list_t *entry = zfs_alloc(hdl,
+ sizeof (zprop_list_t));
+ entry->pl_prop = ZPROP_INVAL;
+ entry->pl_user_prop = zfs_asprintf(hdl, "feature@%s",
+ spa_feature_table[i].fi_uname);
+ entry->pl_width = strlen(entry->pl_user_prop);
+ entry->pl_all = B_TRUE;
+
+ *last = entry;
+ last = &entry->pl_next;
+ }
+ }
+
+ /* add any unsupported features */
+ for (nvp = nvlist_next_nvpair(features, NULL);
+ nvp != NULL; nvp = nvlist_next_nvpair(features, nvp)) {
+ char *propname;
+ boolean_t found;
+ zprop_list_t *entry;
+
+ if (zfeature_is_supported(nvpair_name(nvp)))
+ continue;
+
+ propname = zfs_asprintf(hdl, "unsupported@%s",
+ nvpair_name(nvp));
+
+ /*
+ * Before adding the property to the list make sure that no
+ * other pool already added the same property.
+ */
+ found = B_FALSE;
+ entry = *plp;
+ while (entry != NULL) {
+ if (entry->pl_user_prop != NULL &&
+ strcmp(propname, entry->pl_user_prop) == 0) {
+ found = B_TRUE;
+ break;
+ }
+ entry = entry->pl_next;
+ }
+ if (found) {
+ free(propname);
+ continue;
+ }
+
+ entry = zfs_alloc(hdl, sizeof (zprop_list_t));
+ entry->pl_prop = ZPROP_INVAL;
+ entry->pl_user_prop = propname;
+ entry->pl_width = strlen(entry->pl_user_prop);
+ entry->pl_all = B_TRUE;
+
+ *last = entry;
+ last = &entry->pl_next;
+ }
+