node.c: Tighten node clean up logic.

* Teardown I/O transformers and session only after we've checked if
  the node was already shutdown, to avoid duplicate cleanup attempt.
* Only call node_shutdown on the active shutdown attempt,
  to avoid the duplicate call to node_shutdown in the first place.

bbs/io.c

@@ -128,7 +128,7 @@ int bbs_io_session_unregister(struct bbs_io_transformations *s)
 	RWLIST_UNLOCK(&sessions);
 	if (!i) {
 		/* We traversed the entire list, so this count is accurate */
-		bbs_warning("Transformation %p does not have an active session (%d total)\n", s, total);
+		bbs_warning("Transformation %p does not have an active session (%d total active)\n", s, total);
 	}
 	return i ? 0 : -1;
 }

bbs/node.c

@@ -587,9 +587,6 @@ static void node_shutdown(struct bbs_node *node, int unique)
 	time_t now;
 	int wasloggedin = 0;
 
-	bbs_io_teardown_all_transformers(&node->trans);
-	bbs_io_session_unregister(&node->trans);
-
 	/* Prevent node from being freed until we release the lock. */
 	bbs_node_lock(node);
 	if (!node->active) {
@@ -602,6 +599,9 @@ static void node_shutdown(struct bbs_node *node, int unique)
 
 	now = time(NULL);
 
+	bbs_io_teardown_all_transformers(&node->trans);
+	bbs_io_session_unregister(&node->trans);
+
 	bbs_node_kill_child(node);
 
 	/* Destroy the user */
@@ -711,9 +711,10 @@ int bbs_node_unlink(struct bbs_node *node)
 		/* If bbs_node_shutdown_all was used, nodes are removed from the list
 		 * but not freed there. */
 		bbs_debug(1, "Node %d was already unlinked, freeing directly\n", node->id);
+	} else {
+		node_shutdown(node, 1);
 	}
 
-	node_shutdown(node, 1);
 	/* If unlinking a single node, also free here */
 	node_free(node);
 	return 0;