WIP

Signed-off-by: Niclas Schad <niclas.schad@stackit.cloud>

Author: nschad

pkg/csi/blockstorage/nodeserver.go

@@ -310,19 +310,14 @@ func (ns *nodeServer) NodeGetInfo(ctx context.Context, _ *csi.NodeGetInfoRequest
 	maxVolumesPerNode := DetermineMaxVolumesByFlavor(flavor)
 
 	// Subtract already mounted Volumes
-	emptyPCIeRootPorts, err := mount.GetEmptyPCIeRootPorts()
+	emptyPCIeRootPorts, err := mount.CountNonVirtioBlockDevices()
 	if err != nil {
 		klog.Errorf("[NodeGetInfo] unable to retrieve PCIe root ports %v", err)
-	} else {
-		klog.Infof("[NodeGetInfo] found empty PCIe root ports: %d", emptyPCIeRootPorts)
-		if emptyPCIeRootPorts == 0 {
-			klog.Warningf("[NodeGetInfo] node does not have any free PCIe ports")
-			maxVolumesPerNode = 0
-		} else {
-			maxVolumesPerNode = emptyPCIeRootPorts
-		}
+		emptyPCIeRootPorts = 0
 	}
 
+	maxVolumesPerNode -= emptyPCIeRootPorts
+
 	klog.V(4).Infof("Determined node to support %d volumes", maxVolumesPerNode)
 
 	nodeInfo := &csi.NodeGetInfoResponse{

pkg/csi/util/mount/mount.go

@@ -47,6 +47,11 @@ var (
 	pciAddressRegex = regexp.MustCompile(`^[0-9a-fA-F]{4}:[0-9a-fA-F]{2}:[0-9a-fA-F]{2}\.[0-9a-fA-F]$`)
 )
 
+const (
+	REDHAT_VENDOR       = "0x1af4"
+	VIRTIO_BLOCK_DEVICE = "1042"
+)
+
 type IMount interface {
 	Mounter() *mount.SafeFormatAndMount
 	ScanForAttach(devicePath string) error
@@ -125,11 +130,10 @@ func probeVolume() error {
 	return nil
 }
 
-// GetEmptyPCIeRootPorts returns the number of PCIe Root ports who currently
-// do not have ANY downstream devices, therefore considered "empty". This
-// function is used dynamically how many more devices (in this case "volumes")
-// can be mounted to the given node.
-func GetEmptyPCIeRootPorts() (int64, error) {
+// CountNonVirtioBlockDevices returns the number of PCIe Root ports who
+// are currently occupied by anything else than an VIRTIO 1.0 Block Device
+// returns zero when something went wrong
+func CountNonVirtioBlockDevices() (int64, error) {
 	const pciPath = "/sys/bus/pci/devices"
 
 	// Get all PCI devices
@@ -138,7 +142,7 @@ func GetEmptyPCIeRootPorts() (int64, error) {
 		return 0, fmt.Errorf("failed to read PCI bus: %w", err)
 	}
 
-	emptyCount := 0
+	pcieSlotsOccupiedByNonBlockDevice := 0
 
 	for _, dev := range devices {
 		devPath := filepath.Join(pciPath, dev.Name())
@@ -158,7 +162,7 @@ func GetEmptyPCIeRootPorts() (int64, error) {
 			// 2. Check if the port has downstream devices
 			// If the bridge has children, they appear as subdirectories
 			// matching the PCI address format (e.g., 0000:01:00.0)
-			hasChild := false
+			isNonBLockDevice := false
 			files, err2 := os.ReadDir(devPath)
 			if err2 != nil {
 				klog.Errorf("failed to read dir %s : %v", devPath, err2)
@@ -167,20 +171,36 @@ func GetEmptyPCIeRootPorts() (int64, error) {
 				// Ignore PCI bus directories such as pci001 pci002 and pci010
 				// Devices must follow <domain:bus:device.function> format
 				if pciAddressRegex.MatchString(file.Name()) {
-					hasChild = true
+					isNonBLockDevice = probePCIeDevice(devPath, file, isNonBLockDevice)
 					break
 				}
 			}
 
-			if !hasChild {
-				emptyCount++
+			if !isNonBLockDevice {
+				pcieSlotsOccupiedByNonBlockDevice++
 			}
 		} else {
 			klog.Infof("skipping class %s: path: %s", class, devPath)
 		}
 	}
 
-	return int64(emptyCount), nil
+	return int64(pcieSlotsOccupiedByNonBlockDevice), nil
+}
+
+func probePCIeDevice(devPath string, file os.DirEntry, isNonBLockDevice bool) bool {
+	pciDevicePath := filepath.Join(devPath, file.Name())
+	deviceBuf, err := os.ReadFile(filepath.Join(pciDevicePath, "device"))
+	if err != nil {
+		klog.Errorf("failed to read PCI device file %s : %v", pciDevicePath, err)
+	}
+	vendorBuf, err := os.ReadFile(filepath.Join(pciDevicePath, "vendor"))
+	if err != nil {
+		klog.Errorf("failed to read PCI device vendor %s : %v", pciDevicePath, err)
+	}
+	if strings.TrimSpace(string(vendorBuf)) == REDHAT_VENDOR && strings.TrimSpace(string(deviceBuf)) != VIRTIO_BLOCK_DEVICE {
+		isNonBLockDevice = true
+	}
+	return isNonBLockDevice
 }
 
 // GetDevicePath returns the path of an attached block storage volume, specified by its id.