feat: implement tracking of blockdevice secondaries

This is going to be used to detect disks that are safe to wipe.

For blockdevices, track secondaries as direct references, e.g. encrypted
`STATE` partition might have secondary `vda5`.

For disks, re-map secondaries to be whole devices names, e.g. `vda`.

Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>

api/resource/definitions/block/block.proto

@@ -18,6 +18,7 @@ message DeviceSpec {
   int64 generation = 6;
   string device_path = 7;
   string parent = 8;
+  repeated string secondaries = 9;
 }
 
 // DiscoveredVolumeSpec is the spec for DiscoveredVolumes resource.
@@ -75,6 +76,7 @@ message DiskSpec {
   bool cdrom = 13;
   string dev_path = 14;
   string pretty_size = 15;
+  repeated string secondary_disks = 16;
 }
 
 // EncryptionKey is the spec for volume encryption key.

internal/app/machined/pkg/controllers/block/devices.go

@@ -204,6 +204,10 @@ func (ctrl *DevicesController) processEvent(ctx context.Context, r controller.Ru
 
 			if dev.TypedSpec().Type == "partition" {
 				dev.TypedSpec().Parent = filepath.Base(filepath.Dir(dev.TypedSpec().DevicePath))
+				dev.TypedSpec().Secondaries = nil
+			} else {
+				dev.TypedSpec().Parent = ""
+				dev.TypedSpec().Secondaries = sysblock.ReadSecondaries(ev.DevicePath)
 			}
 
 			dev.TypedSpec().Generation++

internal/app/machined/pkg/controllers/block/disks.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/cosi-project/runtime/pkg/controller"
 	"github.com/cosi-project/runtime/pkg/safe"
+	"github.com/siderolabs/gen/xslices"
 	blkdev "github.com/siderolabs/go-blockdevice/v2/block"
 	"go.uber.org/zap"
 
@@ -90,7 +91,7 @@ func (ctrl *DisksController) Run(ctx context.Context, r controller.Runtime, logg
 
 			lastObservedGenerations[device.Metadata().ID()] = device.TypedSpec().Generation
 
-			if err = ctrl.analyzeBlockDevice(ctx, r, logger.With(zap.String("device", device.Metadata().ID())), device, touchedDisks); err != nil {
+			if err = ctrl.analyzeBlockDevice(ctx, r, logger.With(zap.String("device", device.Metadata().ID())), device, touchedDisks, blockdevices); err != nil {
 				return fmt.Errorf("failed to analyze block device: %w", err)
 			}
 		}
@@ -114,7 +115,10 @@ func (ctrl *DisksController) Run(ctx context.Context, r controller.Runtime, logg
 	}
 }
 
-func (ctrl *DisksController) analyzeBlockDevice(ctx context.Context, r controller.Runtime, logger *zap.Logger, device *block.Device, touchedDisks map[string]struct{}) error {
+//nolint:gocyclo
+func (ctrl *DisksController) analyzeBlockDevice(
+	ctx context.Context, r controller.Runtime, logger *zap.Logger, device *block.Device, touchedDisks map[string]struct{}, allBlockdevices safe.List[*block.Device],
+) error {
 	bd, err := blkdev.NewFromPath(filepath.Join("/dev", device.Metadata().ID()))
 	if err != nil {
 		logger.Debug("failed to open blockdevice", zap.Error(err))
@@ -156,6 +160,18 @@ func (ctrl *DisksController) analyzeBlockDevice(ctx context.Context, r controlle
 		logger.Debug("failed to get properties", zap.Error(err))
 	}
 
+	secondaryDisks := xslices.Map(device.TypedSpec().Secondaries, func(devID string) string {
+		if secondary, ok := allBlockdevices.Find(func(dev *block.Device) bool {
+			return dev.Metadata().ID() == devID
+		}); ok {
+			if secondary.TypedSpec().Parent != "" {
+				return secondary.TypedSpec().Parent
+			}
+		}
+
+		return devID
+	})
+
 	touchedDisks[device.Metadata().ID()] = struct{}{}
 
 	return safe.WriterModify(ctx, r, block.NewDisk(block.NamespaceName, device.Metadata().ID()), func(d *block.Disk) error {
@@ -176,6 +192,8 @@ func (ctrl *DisksController) analyzeBlockDevice(ctx context.Context, r controlle
 		d.TypedSpec().Transport = props.Transport
 		d.TypedSpec().Rotational = props.Rotational
 
+		d.TypedSpec().SecondaryDisks = secondaryDisks
+
 		return nil
 	})
 }

internal/app/machined/pkg/controllers/block/internal/sysblock/sysblock.go

@@ -12,6 +12,7 @@ import (
 	"path/filepath"
 
 	"github.com/mdlayher/kobject"
+	"github.com/siderolabs/gen/xslices"
 )
 
 // Walk the /sys/block filesystem and gather block device information.
@@ -142,3 +143,15 @@ func readPartitions(path string) ([]*kobject.Event, error) {
 
 	return result, nil
 }
+
+// ReadSecondaries reads secondary devices for a given device and returns the list.
+func ReadSecondaries(devPath string) []string {
+	entries, err := os.ReadDir(filepath.Join(devPath, "slaves"))
+	if err != nil {
+		return nil
+	}
+
+	return xslices.Map(entries, func(entry os.DirEntry) string {
+		return entry.Name()
+	})
+}

internal/integration/api/volumes.go

@@ -167,6 +167,13 @@ func (suite *VolumesSuite) TestDisks() {
 					}
 				}
 
+				if strings.HasPrefix(disk.Metadata().ID(), "dm-") {
+					// devicemapper disks should have secondaries
+					suite.Assert().NotEmpty(disk.TypedSpec().SecondaryDisks, "disk: %s", disk.Metadata().ID())
+
+					suite.T().Logf("disk: %s secondaries: %v", disk.Metadata().ID(), disk.TypedSpec().SecondaryDisks)
+				}
+
 				diskNames = append(diskNames, disk.Metadata().ID())
 			}
 

pkg/machinery/resources/block/device.go

@@ -35,6 +35,11 @@ type DeviceSpec struct {
 
 	// Parent (if set) specifies the parent device ID.
 	Parent string `yaml:"parent,omitempty" protobuf:"8"`
+
+	// Secondaries (if set) specifies the secondary device IDs.
+	//
+	// E.g. for a LVM volume secondary is a list of blockdevices that the volume consists of.
+	Secondaries []string `yaml:"secondaries,omitempty" protobuf:"9"`
 }
 
 // NewDevice initializes a BlockDevice resource.

pkg/machinery/resources/block/disk.go

@@ -42,6 +42,12 @@ type DiskSpec struct {
 	SubSystem  string `yaml:"sub_system,omitempty" protobuf:"10"`
 	Transport  string `yaml:"transport,omitempty" protobuf:"11"`
 	Rotational bool   `yaml:"rotational,omitempty" protobuf:"12"`
+
+	// SecondaryDisks (if set) specifies the secondary disk IDs.
+	//
+	// E.g. if the blockdevice secondary is vda5, the secondary disk will be set as vda.
+	// This allows to map secondaries between disks ignoring the partitions.
+	SecondaryDisks []string `yaml:"secondary_disks,omitempty" protobuf:"16"`
 }
 
 // SetSize sets the size of the disk, including the pretty size.

website/content/v1.9/reference/api.md

@@ -805,6 +805,7 @@ DeviceSpec is the spec for devices status.
 | generation | [int64](#int64) |  |  |
 | device_path | [string](#string) |  |  |
 | parent | [string](#string) |  |  |
+| secondaries | [string](#string) | repeated |  |
 
 
 
@@ -912,6 +913,7 @@ DiskSpec is the spec for Disks status.
 | cdrom | [bool](#bool) |  |  |
 | dev_path | [string](#string) |  |  |
 | pretty_size | [string](#string) |  |  |
+| secondary_disks | [string](#string) | repeated |  |