Increment retries when applicable in sync scans.

Reserve nodes whenever writing cluster metrics.

src/main/aerospike/aerospike_scan.c

@@ -892,6 +892,10 @@ as_scan_partitions(
 		}
 
 		uint32_t n_nodes = pt->node_parts.size;
+
+		if (pt->iteration > 1) {
+			as_cluster_add_retries(cluster, n_nodes);
+		}
 
 		// Initialize task.
 		uint32_t error_mutex = 0;

src/main/aerospike/as_metrics_writer.c

@@ -543,8 +543,8 @@ as_metrics_write_cluster(as_error* err, as_metrics_writer* mw, as_cluster* clust
 	}
 	as_string_builder_append(&sb, "],[");
 
-	// Since this function is only called from the cluster tend thread, there is no need to reserve nodes.
-	as_nodes* nodes = cluster->nodes;
+	as_nodes* nodes = as_nodes_reserve(cluster);
+
 	for (uint32_t i = 0; i < nodes->size; i++) {
 		as_node* node = nodes->array[i];
 
@@ -553,6 +553,7 @@ as_metrics_write_cluster(as_error* err, as_metrics_writer* mw, as_cluster* clust
 		}
 		as_metrics_write_node(mw, &sb, node);
 	}
+	as_nodes_release(nodes);
 	as_string_builder_append(&sb, "]]");
 
 	as_string_builder_append_newline(&sb);