refactor: replace the old v1 mount package with new one

Re-design some methods, simplify flows and allow more simple
interactions.

Learn from mistakes and design better methods.

Fixes siderolabs#9471

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

internal/app/init/main.go

@@ -13,18 +13,16 @@ import (
 	"os/signal"
 	"path/filepath"
 	"runtime"
-	"strings"
 	"syscall"
 	"time"
 
-	"github.com/freddierice/go-losetup/v2"
 	"github.com/klauspost/cpuid/v2"
 	"github.com/siderolabs/go-kmsg"
 	"github.com/siderolabs/go-procfs/procfs"
 	"golang.org/x/sys/unix"
 
-	"github.com/siderolabs/talos/internal/pkg/mount"
 	"github.com/siderolabs/talos/internal/pkg/mount/switchroot"
+	"github.com/siderolabs/talos/internal/pkg/mount/v2"
 	"github.com/siderolabs/talos/internal/pkg/rng"
 	"github.com/siderolabs/talos/internal/pkg/secureboot"
 	"github.com/siderolabs/talos/internal/pkg/secureboot/tpm2"
@@ -38,31 +36,27 @@ func init() {
 	runtime.MemProfileRate = 0
 }
 
-func run() (err error) {
+func run() error {
 	// Mount the pseudo devices.
-	pseudo, err := mount.PseudoMountPoints()
-	if err != nil {
-		return err
-	}
+	pseudoMountPoints := mount.Pseudo()
 
-	if err = mount.Mount(pseudo); err != nil {
+	if _, err := pseudoMountPoints.Mount(); err != nil {
 		return err
 	}
 
 	// Setup logging to /dev/kmsg.
-	err = kmsg.SetupLogger(nil, "[talos] [initramfs]", nil)
-	if err != nil {
+	if err := kmsg.SetupLogger(nil, "[talos] [initramfs]", nil); err != nil {
 		return err
 	}
 
 	// Seed RNG.
-	if err = rng.TPMSeed(); err != nil {
+	if err := rng.TPMSeed(); err != nil {
 		// not making this fatal error
 		log.Printf("failed to seed from the TPM: %s", err)
 	}
 
 	// extend PCR 11 with enter-initrd
-	if err = tpm2.PCRExtend(secureboot.UKIPCR, []byte(secureboot.EnterInitrd)); err != nil {
+	if err := tpm2.PCRExtend(secureboot.UKIPCR, []byte(secureboot.EnterInitrd)); err != nil {
 		return fmt.Errorf("failed to extend PCR %d with enter-initrd: %v", secureboot.UKIPCR, err)
 	}
 
@@ -71,24 +65,24 @@ func run() (err error) {
 	cpuInfo()
 
 	// Mount the rootfs.
-	if err = mountRootFS(); err != nil {
+	if err := mountRootFS(); err != nil {
 		return err
 	}
 
 	// Bind mount the lib/firmware if needed.
-	if err = bindMountFirmware(); err != nil {
+	if err := bindMountFirmware(); err != nil {
 		return err
 	}
 
 	// Bind mount /.extra if needed.
-	if err = bindMountExtra(); err != nil {
+	if err := bindMountExtra(); err != nil {
 		return err
 	}
 
 	// Switch into the new rootfs.
 	log.Println("entering the rootfs")
 
-	return switchroot.Switch(constants.NewRoot, pseudo)
+	return switchroot.Switch(constants.NewRoot, pseudoMountPoints)
 }
 
 func recovery() {
@@ -131,12 +125,14 @@ func mountRootFS() error {
 
 	// if no extensions found use plain squashfs mount
 	if len(extensionsConfig.Layers) == 0 {
-		squashfs, err := mount.SquashfsMountPoints(constants.NewRoot)
+		squashfs, err := mount.Squashfs(constants.NewRoot, "/"+constants.RootfsAsset)
 		if err != nil {
 			return err
 		}
 
-		return mount.Mount(squashfs)
+		_, err = squashfs.Mount()
+
+		return err
 	}
 
 	// otherwise compose overlay mounts
@@ -145,9 +141,10 @@ func mountRootFS() error {
 		image string
 	}
 
-	var layers []layer
-
-	squashfs := mount.NewMountPoints()
+	var (
+		layers         []layer
+		squashfsPoints mount.Points
+	)
 
 	// going in the inverse order as earlier layers are overlayed on top of the latter ones
 	for i := len(extensionsConfig.Layers) - 1; i >= 0; i-- {
@@ -167,29 +164,30 @@ func mountRootFS() error {
 	overlays := make([]string, 0, len(layers))
 
 	for _, layer := range layers {
-		dev, err := losetup.Attach(layer.image, 0, true)
+		target := filepath.Join(constants.ExtensionLayers, layer.name)
+
+		point, err := mount.Squashfs(target, layer.image)
 		if err != nil {
 			return err
 		}
 
-		p := mount.NewMountPoint(dev.Path(), "/"+layer.name, "squashfs", unix.MS_RDONLY|unix.MS_I_VERSION, "", mount.WithPrefix(constants.ExtensionLayers), mount.WithFlags(mount.ReadOnly|mount.Shared))
-
-		overlays = append(overlays, p.Target())
-		squashfs.Set(layer.name, p)
+		squashfsPoints = append(squashfsPoints, point)
+		overlays = append(overlays, target)
 	}
 
-	if err := mount.Mount(squashfs); err != nil {
+	squashfsUnmounter, err := squashfsPoints.Mount()
+	if err != nil {
 		return err
 	}
 
-	overlay := mount.NewMountPoints()
-	overlay.Set(constants.NewRoot, mount.NewMountPoint(strings.Join(overlays, ":"), constants.NewRoot, "", unix.MS_I_VERSION, "", mount.WithFlags(mount.ReadOnly|mount.ReadonlyOverlay|mount.Shared)))
+	overlayPoint := mount.NewReadonlyOverlay(overlays, constants.NewRoot, mount.WithShared(), mount.WithFlags(unix.MS_I_VERSION))
 
-	if err := mount.Mount(overlay); err != nil {
+	_, err = overlayPoint.Mount()
+	if err != nil {
 		return err
 	}
 
-	if err := mount.Unmount(squashfs); err != nil {
+	if err = squashfsUnmounter(); err != nil {
 		return err
 	}
 

internal/app/machined/main.go

@@ -35,7 +35,7 @@ import (
 	"github.com/siderolabs/talos/internal/app/maintenance"
 	"github.com/siderolabs/talos/internal/app/poweroff"
 	"github.com/siderolabs/talos/internal/app/trustd"
-	"github.com/siderolabs/talos/internal/pkg/mount"
+	"github.com/siderolabs/talos/internal/pkg/mount/v2"
 	"github.com/siderolabs/talos/pkg/httpdefaults"
 	"github.com/siderolabs/talos/pkg/machinery/api/common"
 	"github.com/siderolabs/talos/pkg/machinery/api/machine"

internal/app/machined/pkg/runtime/v1alpha1/v1alpha1_sequencer.go

@@ -94,7 +94,6 @@ func (*Sequencer) Initialize(r runtime.Runtime) []runtime.Phase {
 			"systemRequirements",
 			EnforceKSPPRequirements,
 			SetupSystemDirectory,
-			MountBPFFS,
 			MountCgroups,
 			MountPseudoFilesystems,
 			SetRLimit,

internal/app/machined/pkg/runtime/v1alpha1/v1alpha1_sequencer_tasks.go

@@ -168,7 +168,7 @@ func CreateSystemCgroups(runtime.Sequence, any) (runtime.TaskExecutionFunc, stri
 		if r.State().Platform().Mode() != runtime.ModeContainer {
 			// assert that cgroupsv2 is being used when running not in container mode,
 			// as Talos sets up cgroupsv2 on its own
-			if cgroups.Mode() != cgroups.Unified && !mount.ForceGGroupsV1() {
+			if cgroups.Mode() != cgroups.Unified && !mountv2.ForceGGroupsV1() {
 				return errors.New("cgroupsv2 should be used")
 			}
 		}
@@ -342,45 +342,21 @@ func CreateSystemCgroups(runtime.Sequence, any) (runtime.TaskExecutionFunc, stri
 	}, "CreateSystemCgroups"
 }
 
-// MountBPFFS represents the MountBPFFS task.
-func MountBPFFS(runtime.Sequence, any) (runtime.TaskExecutionFunc, string) {
-	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) (err error) {
-		var mountpoints *mount.Points
-
-		mountpoints, err = mount.BPFMountPoints()
-		if err != nil {
-			return err
-		}
-
-		return mount.Mount(mountpoints)
-	}, "mountBPFFS"
-}
-
 // MountCgroups represents the MountCgroups task.
 func MountCgroups(runtime.Sequence, any) (runtime.TaskExecutionFunc, string) {
-	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) (err error) {
-		var mountpoints *mount.Points
-
-		mountpoints, err = mount.CGroupMountPoints()
-		if err != nil {
-			return err
-		}
+	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) error {
+		_, err := mountv2.CGroupMountPoints().Mount()
 
-		return mount.Mount(mountpoints)
+		return err
 	}, "mountCgroups"
 }
 
 // MountPseudoFilesystems represents the MountPseudoFilesystems task.
 func MountPseudoFilesystems(runtime.Sequence, any) (runtime.TaskExecutionFunc, string) {
-	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) (err error) {
-		var mountpoints *mount.Points
-
-		mountpoints, err = mount.PseudoSubMountPoints()
-		if err != nil {
-			return err
-		}
+	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) error {
+		_, err := mountv2.PseudoSubMountPoints().Mount()
 
-		return mount.Mount(mountpoints)
+		return err
 	}, "mountPseudoFilesystems"
 }
 
@@ -722,10 +698,9 @@ func StartDashboard(_ runtime.Sequence, _ any) (runtime.TaskExecutionFunc, strin
 // StartUdevd represents the task to start udevd.
 func StartUdevd(runtime.Sequence, any) (runtime.TaskExecutionFunc, string) {
 	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) (err error) {
-		mp := mount.NewMountPoints()
-		mp.Set("udev-data", mount.NewMountPoint("", constants.UdevDir, "", unix.MS_I_VERSION, "", mount.WithFlags(mount.Overlay|mount.SystemOverlay|mount.Shared)))
+		mp := mountv2.NewSystemOverlay([]string{constants.UdevDir}, constants.UdevDir, mountv2.WithShared(), mountv2.WithFlags(unix.MS_I_VERSION))
 
-		if err = mount.Mount(mp); err != nil {
+		if _, err = mp.Mount(); err != nil {
 			return err
 		}
 
@@ -864,14 +839,9 @@ func StopAllServices(runtime.Sequence, any) (runtime.TaskExecutionFunc, string)
 // MountOverlayFilesystems represents the MountOverlayFilesystems task.
 func MountOverlayFilesystems(runtime.Sequence, any) (runtime.TaskExecutionFunc, string) {
 	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) (err error) {
-		var mountpoints *mount.Points
-
-		mountpoints, err = mount.OverlayMountPoints()
-		if err != nil {
-			return err
-		}
+		_, err = mountv2.OverlayMountPoints().Mount()
 
-		return mount.Mount(mountpoints)
+		return err
 	}, "mountOverlayFilesystems"
 }
 
@@ -1191,14 +1161,7 @@ func existsAndIsFile(p string) (err error) {
 // UnmountOverlayFilesystems represents the UnmountOverlayFilesystems task.
 func UnmountOverlayFilesystems(runtime.Sequence, any) (runtime.TaskExecutionFunc, string) {
 	return func(ctx context.Context, logger *log.Logger, r runtime.Runtime) (err error) {
-		var mountpoints *mount.Points
-
-		mountpoints, err = mount.OverlayMountPoints()
-		if err != nil {
-			return err
-		}
-
-		return mount.Unmount(mountpoints)
+		return mountv2.OverlayMountPoints().Unmount()
 	}, "unmountOverlayFilesystems"
 }
 
@@ -1266,7 +1229,7 @@ func UnmountPodMounts(runtime.Sequence, any) (runtime.TaskExecutionFunc, string)
 			if strings.HasPrefix(mountpoint, constants.EphemeralMountPoint+"/") {
 				logger.Printf("unmounting %s\n", mountpoint)
 
-				if err = mount.SafeUnmount(ctx, logger, mountpoint); err != nil {
+				if err = mountv2.SafeUnmount(ctx, logger.Printf, mountpoint); err != nil {
 					if errors.Is(err, syscall.EINVAL) {
 						log.Printf("ignoring unmount error %s: %v", mountpoint, err)
 					} else {
@@ -1315,7 +1278,7 @@ func UnmountSystemDiskBindMounts(runtime.Sequence, any) (runtime.TaskExecutionFu
 			if strings.HasPrefix(device, devname) && device != devname {
 				logger.Printf("unmounting %s\n", mountpoint)
 
-				if err = mount.SafeUnmount(ctx, logger, mountpoint); err != nil {
+				if err = mountv2.SafeUnmount(ctx, logger.Printf, mountpoint); err != nil {
 					if errors.Is(err, syscall.EINVAL) {
 						log.Printf("ignoring unmount error %s: %v", mountpoint, err)
 					} else {
@@ -2257,7 +2220,7 @@ func ForceCleanup(runtime.Sequence, any) (runtime.TaskExecutionFunc, string) {
 			logger.Printf("error killing all procs: %s", err)
 		}
 
-		if err := mount.UnmountAll(); err != nil {
+		if err := mountv2.UnmountAll(); err != nil {
 			logger.Printf("error unmounting: %s", err)
 		}
 

internal/app/machined/pkg/system/services/extension.go

@@ -26,7 +26,7 @@ import (
 	"github.com/siderolabs/talos/internal/app/machined/pkg/system/runner/restart"
 	"github.com/siderolabs/talos/internal/pkg/capability"
 	"github.com/siderolabs/talos/internal/pkg/environment"
-	"github.com/siderolabs/talos/internal/pkg/mount"
+	"github.com/siderolabs/talos/internal/pkg/mount/v2"
 	"github.com/siderolabs/talos/pkg/conditions"
 	"github.com/siderolabs/talos/pkg/machinery/constants"
 	extservices "github.com/siderolabs/talos/pkg/machinery/extensions/services"
@@ -39,7 +39,7 @@ import (
 type Extension struct {
 	Spec extservices.Spec
 
-	overlay *mount.Point
+	overlayUnmounter func() error
 }
 
 // ID implements the Service interface.
@@ -50,21 +50,23 @@ func (svc *Extension) ID(r runtime.Runtime) string {
 // PreFunc implements the Service interface.
 func (svc *Extension) PreFunc(ctx context.Context, r runtime.Runtime) error {
 	// re-mount service rootfs as overlay rw mount to allow containerd to mount there /dev, /proc, etc.
-	svc.overlay = mount.NewMountPoint(
-		"",
-		filepath.Join(constants.ExtensionServiceRootfsPath, svc.Spec.Name),
-		"",
-		0,
-		"",
-		mount.WithFlags(mount.Overlay|mount.SystemOverlay),
+	rootfsPath := filepath.Join(constants.ExtensionServiceRootfsPath, svc.Spec.Name)
+
+	overlay := mount.NewSystemOverlay(
+		[]string{rootfsPath},
+		rootfsPath,
 	)
 
-	return svc.overlay.Mount()
+	var err error
+
+	svc.overlayUnmounter, err = overlay.Mount()
+
+	return err
 }
 
 // PostFunc implements the Service interface.
 func (svc *Extension) PostFunc(r runtime.Runtime, state events.ServiceState) (err error) {
-	return svc.overlay.Unmount()
+	return svc.overlayUnmounter()
 }
 
 // Condition implements the Service interface.