Networt: Fix incorrect handling of instances in UsedByInstanceDevices (…

…#14299)

During cherry-pick from Incus of refactor of this function in
e5f5b88 the project filtering logic was
incorrectly returning rather than continuing to next instance.

This meant some instances were being excluded incorrectly.

Also fixes a potential issue with concurrent modification of the leases
slice in `bridge.Leases()` when collecting leases from each cluster
member concurrently.

Fixes #13412

lxd/network/driver_bridge.go

@@ -3632,6 +3632,18 @@ func (n *bridge) Leases(projectName string, clientType request.ClientType) ([]ap
 			return nil, err
 		}
 
+		leasesCh := make(chan api.NetworkLease)
+
+		var wg sync.WaitGroup
+		wg.Add(1)
+		go func() {
+			for lease := range leasesCh {
+				leases = append(leases, lease)
+			}
+
+			wg.Done()
+		}()
+
 		err = notifier(func(client lxd.InstanceServer) error {
 			memberLeases, err := client.GetNetworkLeases(n.name)
 			if err != nil {
@@ -3641,12 +3653,17 @@ func (n *bridge) Leases(projectName string, clientType request.ClientType) ([]ap
 			// Add local leases from other members, filtering them for MACs that belong to the project.
 			for _, lease := range memberLeases {
 				if lease.Hwaddr != "" && shared.ValueInSlice(lease.Hwaddr, projectMacs) {
-					leases = append(leases, lease)
+					leasesCh <- lease
 				}
 			}
 
 			return nil
 		})
+
+		// Finish up and wait for go routine.
+		close(leasesCh)
+		wg.Wait()
+
 		if err != nil {
 			return nil, err
 		}

lxd/network/network_utils.go

@@ -82,7 +82,7 @@ func MACDevName(mac net.HardwareAddr) string {
 func UsedByInstanceDevices(s *state.State, networkProjectName string, networkName string, networkType string, usageFunc func(inst db.InstanceArgs, nicName string, nicConfig map[string]string) error, filters ...cluster.InstanceFilter) error {
 	// Get the instances.
 	projects := map[string]api.Project{}
-	instances := []db.InstanceArgs{}
+	var instances []db.InstanceArgs
 
 	err := s.DB.Cluster.Transaction(context.TODO(), func(ctx context.Context, tx *db.ClusterTx) error {
 		return tx.InstanceList(ctx, func(inst db.InstanceArgs, p api.Project) error {
@@ -105,7 +105,7 @@ func UsedByInstanceDevices(s *state.State, networkProjectName string, networkNam
 
 		// Skip instances who's effective network project doesn't match this Network's project.
 		if instNetworkProject != networkProjectName {
-			return nil
+			continue
 		}
 
 		// Look for NIC devices using this network.