Merge pull request #258 from thaJeztah/19.03_backport_update_buildkit

[19.03 backport] vendor: update buildkit to 37d53758

builder/builder-next/adapters/containerimage/pull.go

@@ -135,7 +135,7 @@ func (is *imageSource) resolveRemote(ctx context.Context, ref string, platform *
 		dt   []byte
 	}
 	res, err := is.g.Do(ctx, ref, func(ctx context.Context) (interface{}, error) {
-		dgst, dt, err := imageutil.Config(ctx, ref, is.getResolver(ctx, is.ResolverOpt, ref, sm), is.ContentStore, platform)
+		dgst, dt, err := imageutil.Config(ctx, ref, is.getResolver(ctx, is.ResolverOpt, ref, sm), is.ContentStore, nil, platform)
 		if err != nil {
 			return nil, err
 		}

vendor.conf

@@ -27,7 +27,7 @@ github.com/imdario/mergo                            7c29201646fa3de8506f70121347
 golang.org/x/sync                                   e225da77a7e68af35c70ccbf71af2b83e6acac3c
 
 # buildkit
-github.com/moby/buildkit                            f238f1efb04f00bf0cc147141fda9ddb55c8bc49
+github.com/moby/buildkit                            37d53758a68d9f5cede1806dbb2da7c3caa8d5bc
 github.com/tonistiigi/fsutil                        3bbb99cdbd76619ab717299830c60f6f2a533a6b
 github.com/grpc-ecosystem/grpc-opentracing          8e809c8a86450a29b90dcc9efbf062d0fe6d9746
 github.com/opentracing/opentracing-go               1361b9cd60be79c4c3a7fa9841b3c132e40066a7

vendor/github.com/moby/buildkit/README.md

@@ -184,6 +184,19 @@ The local client will copy the files directly to the client. This is useful if B
 buildctl build ... --output type=local,dest=path/to/output-dir
 ```
 
+To export specific files use multi-stage builds with a scratch stage and copy the needed files into that stage with `COPY --from`.
+```dockerfile
+...
+FROM scratch as testresult
+
+COPY --from=builder /usr/src/app/testresult.xml .
+...
+```
+
+```
+buildctl build ... --opt target=testresult --output type=local,dest=path/to/output-dir
+```
+
 Tar exporter is similar to local exporter but transfers the files through a tarball.
 
 ```
@@ -268,6 +281,16 @@ export BUILDKIT_HOST=tcp://0.0.0.0:1234
 buildctl build --help
 ```
 
+To run client and an ephemeral daemon in a single container ("daemonless mode"):
+
+```
+docker run -it --rm --privileged -v /path/to/dir:/tmp/work --entrypoint buildctl-daemonless.sh moby/buildkit:master build --frontend dockerfile.v0 --local context=/tmp/work --local dockerfile=/tmp/work
+```
+or
+```
+docker run -it --rm --security-opt seccomp=unconfined --security-opt apparmor=unconfined -e BUILDKITD_FLAGS=--oci-worker-no-process-sandbox -v /path/to/dir:/tmp/work --entrypoint buildctl-daemonless.sh moby/buildkit:master-rootless build --frontend dockerfile.v0 --local context=/tmp/work --local dockerfile=/tmp/work
+```
+
 The images can be also built locally using `./hack/dockerfiles/test.Dockerfile` (or `./hack/dockerfiles/test.buildkit.Dockerfile` if you already have BuildKit).
 Run `make images` to build the images as `moby/buildkit:local` and `moby/buildkit:local-rootless`.
 

vendor/github.com/moby/buildkit/cache/contenthash/checksum.go

@@ -60,6 +60,10 @@ func SetCacheContext(ctx context.Context, md *metadata.StorageItem, cc CacheCont
 	return getDefaultManager().SetCacheContext(ctx, md, cc)
 }
 
+func ClearCacheContext(md *metadata.StorageItem) {
+	getDefaultManager().clearCacheContext(md.ID())
+}
+
 type CacheContext interface {
 	Checksum(ctx context.Context, ref cache.Mountable, p string, followLinks bool) (digest.Digest, error)
 	ChecksumWildcard(ctx context.Context, ref cache.Mountable, p string, followLinks bool) (digest.Digest, error)
@@ -142,6 +146,12 @@ func (cm *cacheManager) SetCacheContext(ctx context.Context, md *metadata.Storag
 	return nil
 }
 
+func (cm *cacheManager) clearCacheContext(id string) {
+	cm.lruMu.Lock()
+	cm.lru.Remove(id)
+	cm.lruMu.Unlock()
+}
+
 type cacheContext struct {
 	mu    sync.RWMutex
 	md    *metadata.StorageItem

vendor/github.com/moby/buildkit/cache/manager.go

@@ -125,7 +125,7 @@ func (cm *cacheManager) GetFromSnapshotter(ctx context.Context, id string, opts
 }
 
 // get requires manager lock to be taken
-func (cm *cacheManager) get(ctx context.Context, id string, fromSnapshotter bool, opts ...RefOption) (ImmutableRef, error) {
+func (cm *cacheManager) get(ctx context.Context, id string, fromSnapshotter bool, opts ...RefOption) (*immutableRef, error) {
 	rec, err := cm.getRecord(ctx, id, fromSnapshotter, opts...)
 	if err != nil {
 		return nil, err
@@ -193,7 +193,7 @@ func (cm *cacheManager) getRecord(ctx context.Context, id string, fromSnapshotte
 		return nil, errors.Wrap(errNotFound, err.Error())
 	}
 
-	var parent ImmutableRef
+	var parent *immutableRef
 	if info.Parent != "" {
 		parent, err = cm.get(ctx, info.Parent, fromSnapshotter, append(opts, NoUpdateLastUsed)...)
 		if err != nil {
@@ -201,7 +201,9 @@ func (cm *cacheManager) getRecord(ctx context.Context, id string, fromSnapshotte
 		}
 		defer func() {
 			if retErr != nil {
-				parent.Release(context.TODO())
+				parent.mu.Lock()
+				parent.release(context.TODO())
+				parent.mu.Unlock()
 			}
 		}()
 	}
@@ -224,9 +226,6 @@ func (cm *cacheManager) getRecord(ctx context.Context, id string, fromSnapshotte
 	}
 
 	if err := initializeMetadata(rec, opts...); err != nil {
-		if parent != nil {
-			parent.Release(context.TODO())
-		}
 		return nil, err
 	}
 
@@ -237,18 +236,18 @@ func (cm *cacheManager) getRecord(ctx context.Context, id string, fromSnapshotte
 func (cm *cacheManager) New(ctx context.Context, s ImmutableRef, opts ...RefOption) (MutableRef, error) {
 	id := identity.NewID()
 
-	var parent ImmutableRef
+	var parent *immutableRef
 	var parentID string
 	if s != nil {
-		var err error
-		parent, err = cm.Get(ctx, s.ID(), NoUpdateLastUsed)
+		p, err := cm.Get(ctx, s.ID(), NoUpdateLastUsed)
 		if err != nil {
 			return nil, err
 		}
-		if err := parent.Finalize(ctx, true); err != nil {
+		if err := p.Finalize(ctx, true); err != nil {
 			return nil, err
 		}
-		parentID = parent.ID()
+		parentID = p.ID()
+		parent = p.(*immutableRef)
 	}
 
 	if err := cm.Snapshotter.Prepare(ctx, id, parentID); err != nil {
@@ -737,6 +736,10 @@ func CachePolicyRetain(m withMetadata) error {
 	return queueCachePolicy(m.Metadata(), cachePolicyRetain)
 }
 
+func CachePolicyDefault(m withMetadata) error {
+	return queueCachePolicy(m.Metadata(), cachePolicyDefault)
+}
+
 func WithDescription(descr string) RefOption {
 	return func(m withMetadata) error {
 		return queueDescription(m.Metadata(), descr)

vendor/github.com/moby/buildkit/cache/refs.go

@@ -50,7 +50,7 @@ type cacheRecord struct {
 
 	mutable bool
 	refs    map[ref]struct{}
-	parent  ImmutableRef
+	parent  *immutableRef
 	md      *metadata.StorageItem
 
 	// dead means record is marked as deleted
@@ -126,14 +126,17 @@ func (cr *cacheRecord) Size(ctx context.Context) (int64, error) {
 }
 
 func (cr *cacheRecord) Parent() ImmutableRef {
-	return cr.parentRef(true)
+	if p := cr.parentRef(true); p != nil { // avoid returning typed nil pointer
+		return p
+	}
+	return nil
 }
 
-func (cr *cacheRecord) parentRef(hidden bool) ImmutableRef {
-	if cr.parent == nil {
+func (cr *cacheRecord) parentRef(hidden bool) *immutableRef {
+	p := cr.parent
+	if p == nil {
 		return nil
 	}
-	p := cr.parent.(*immutableRef)
 	p.mu.Lock()
 	defer p.mu.Unlock()
 	return p.ref(hidden)
@@ -181,7 +184,7 @@ func (cr *cacheRecord) Mount(ctx context.Context, readonly bool) (snapshot.Mount
 func (cr *cacheRecord) remove(ctx context.Context, removeSnapshot bool) error {
 	delete(cr.cm.records, cr.ID())
 	if cr.parent != nil {
-		if err := cr.parent.(*immutableRef).release(ctx); err != nil {
+		if err := cr.parent.release(ctx); err != nil {
 			return err
 		}
 	}
@@ -315,7 +318,7 @@ func (sr *mutableRef) updateLastUsed() bool {
 	return sr.triggerLastUsed
 }
 
-func (sr *mutableRef) commit(ctx context.Context) (ImmutableRef, error) {
+func (sr *mutableRef) commit(ctx context.Context) (*immutableRef, error) {
 	if !sr.mutable || len(sr.refs) == 0 {
 		return nil, errors.Wrapf(errInvalid, "invalid mutable ref %p", sr)
 	}
@@ -398,7 +401,7 @@ func (sr *mutableRef) release(ctx context.Context) error {
 			}
 		}
 		if sr.parent != nil {
-			if err := sr.parent.(*immutableRef).release(ctx); err != nil {
+			if err := sr.parent.release(ctx); err != nil {
 				return err
 			}
 		}

vendor/github.com/moby/buildkit/client/llb/imagemetaresolver/resolver.go

@@ -87,7 +87,7 @@ func (imr *imageMetaResolver) ResolveImageConfig(ctx context.Context, ref string
 		return res.dgst, res.config, nil
 	}
 
-	dgst, config, err := imageutil.Config(ctx, ref, imr.resolver, imr.buffer, platform)
+	dgst, config, err := imageutil.Config(ctx, ref, imr.resolver, imr.buffer, nil, platform)
 	if err != nil {
 		return "", nil, err
 	}

vendor/github.com/moby/buildkit/control/control.go

@@ -3,6 +3,7 @@ package control
 import (
 	"context"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	controlapi "github.com/moby/buildkit/api/services/control"
@@ -17,6 +18,7 @@ import (
 	"github.com/moby/buildkit/solver"
 	"github.com/moby/buildkit/solver/llbsolver"
 	"github.com/moby/buildkit/solver/pb"
+	"github.com/moby/buildkit/util/imageutil"
 	"github.com/moby/buildkit/util/throttle"
 	"github.com/moby/buildkit/worker"
 	"github.com/pkg/errors"
@@ -42,6 +44,7 @@ type Controller struct { // TODO: ControlService
 	gatewayForwarder *controlgateway.GatewayForwarder
 	throttledGC      func()
 	gcmu             sync.Mutex
+	buildCount       int64
 }
 
 func NewController(opt Opt) (*Controller, error) {
@@ -110,6 +113,10 @@ func (c *Controller) DiskUsage(ctx context.Context, r *controlapi.DiskUsageReque
 }
 
 func (c *Controller) Prune(req *controlapi.PruneRequest, stream controlapi.Control_PruneServer) error {
+	if atomic.LoadInt64(&c.buildCount) == 0 {
+		imageutil.CancelCacheLeases()
+	}
+
 	ch := make(chan client.UsageInfo)
 
 	eg, ctx := errgroup.WithContext(stream.Context())
@@ -207,6 +214,9 @@ func translateLegacySolveRequest(req *controlapi.SolveRequest) error {
 }
 
 func (c *Controller) Solve(ctx context.Context, req *controlapi.SolveRequest) (*controlapi.SolveResponse, error) {
+	atomic.AddInt64(&c.buildCount, 1)
+	defer atomic.AddInt64(&c.buildCount, -1)
+
 	if err := translateLegacySolveRequest(req); err != nil {
 		return nil, err
 	}

vendor/github.com/moby/buildkit/frontend/dockerfile/dockerfile2llb/convert_runmount.go

@@ -3,8 +3,12 @@
 package dockerfile2llb
 
 import (
+	"fmt"
+	"os"
 	"path"
 	"path/filepath"
+	"strconv"
+	"strings"
 
 	"github.com/moby/buildkit/client/llb"
 	"github.com/moby/buildkit/frontend/dockerfile/instructions"
@@ -40,6 +44,40 @@ func detectRunMount(cmd *command, allDispatchStates *dispatchStates) bool {
 	return false
 }
 
+func setCacheUIDGIDFileOp(m *instructions.Mount, st llb.State) llb.State {
+	uid := 0
+	gid := 0
+	mode := os.FileMode(0755)
+	if m.UID != nil {
+		uid = int(*m.UID)
+	}
+	if m.GID != nil {
+		gid = int(*m.GID)
+	}
+	if m.Mode != nil {
+		mode = os.FileMode(*m.Mode)
+	}
+	return st.File(llb.Mkdir("/cache", mode, llb.WithUIDGID(uid, gid)), llb.WithCustomName("[internal] settings cache mount permissions"))
+}
+
+func setCacheUIDGID(m *instructions.Mount, st llb.State, fileop bool) llb.State {
+	if fileop {
+		return setCacheUIDGIDFileOp(m, st)
+	}
+
+	var b strings.Builder
+	if m.UID != nil {
+		b.WriteString(fmt.Sprintf("chown %d /mnt/cache;", *m.UID))
+	}
+	if m.GID != nil {
+		b.WriteString(fmt.Sprintf("chown :%d /mnt/cache;", *m.GID))
+	}
+	if m.Mode != nil {
+		b.WriteString(fmt.Sprintf("chmod %s /mnt/cache;", strconv.FormatUint(*m.Mode, 8)))
+	}
+	return llb.Image("busybox").Run(llb.Shlex(fmt.Sprintf("sh -c 'mkdir -p /mnt/cache;%s'", b.String())), llb.WithCustomName("[internal] settings cache mount permissions")).AddMount("/mnt", st)
+}
+
 func dispatchRunMounts(d *dispatchState, c *instructions.RunCommand, sources []*dispatchState, opt dispatchOpt) ([]llb.RunOption, error) {
 	var out []llb.RunOption
 	mounts := instructions.GetMounts(c)
@@ -97,7 +135,13 @@ func dispatchRunMounts(d *dispatchState, c *instructions.RunCommand, sources []*
 		}
 		if src := path.Join("/", mount.Source); src != "/" {
 			mountOpts = append(mountOpts, llb.SourcePath(src))
+		} else {
+			if mount.UID != nil || mount.GID != nil || mount.Mode != nil {
+				st = setCacheUIDGID(mount, st, useFileOp(opt.buildArgValues, opt.llbCaps))
+				mountOpts = append(mountOpts, llb.SourcePath("/cache"))
+			}
 		}
+
 		out = append(out, llb.AddMount(target, st, mountOpts...))
 
 		d.ctxPaths[path.Join("/", filepath.ToSlash(mount.Source))] = struct{}{}

vendor/github.com/moby/buildkit/frontend/dockerfile/instructions/commands_runmount.go

@@ -206,18 +206,18 @@ func parseMount(value string) (*Mount, error) {
 		}
 	}
 
-	fileInfoAllowed := m.Type == MountTypeSecret || m.Type == MountTypeSSH
+	fileInfoAllowed := m.Type == MountTypeSecret || m.Type == MountTypeSSH || m.Type == MountTypeCache
 
 	if m.Mode != nil && !fileInfoAllowed {
-		return nil, errors.Errorf("mode not allowed for %q type mounts")
+		return nil, errors.Errorf("mode not allowed for %q type mounts", m.Type)
 	}
 
 	if m.UID != nil && !fileInfoAllowed {
-		return nil, errors.Errorf("uid not allowed for %q type mounts")
+		return nil, errors.Errorf("uid not allowed for %q type mounts", m.Type)
 	}
 
 	if m.GID != nil && !fileInfoAllowed {
-		return nil, errors.Errorf("gid not allowed for %q type mounts")
+		return nil, errors.Errorf("gid not allowed for %q type mounts", m.Type)
 	}
 
 	if roAuto {

vendor/github.com/moby/buildkit/frontend/dockerfile/parser/parser.go

@@ -35,7 +35,7 @@ type Node struct {
 	Original   string          // original line used before parsing
 	Flags      []string        // only top Node should have this set
 	StartLine  int             // the line in the original dockerfile where the node begins
-	endLine    int             // the line in the original dockerfile where the node ends
+	EndLine    int             // the line in the original dockerfile where the node ends
 }
 
 // Dump dumps the AST defined by `node` as a list of sexps.
@@ -65,7 +65,7 @@ func (node *Node) Dump() string {
 
 func (node *Node) lines(start, end int) {
 	node.StartLine = start
-	node.endLine = end
+	node.EndLine = end
 }
 
 // AddChild adds a new child node, and updates line information
@@ -74,7 +74,7 @@ func (node *Node) AddChild(child *Node, startLine, endLine int) {
 	if node.StartLine < 0 {
 		node.StartLine = startLine
 	}
-	node.endLine = endLine
+	node.EndLine = endLine
 	node.Children = append(node.Children, child)
 }
 

vendor/github.com/moby/buildkit/snapshot/blobmapping/snapshotter.go

@@ -2,6 +2,7 @@ package blobmapping
 
 import (
 	"context"
+	"time"
 
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/snapshots"
@@ -122,6 +123,16 @@ func (s *Snapshotter) SetBlob(ctx context.Context, key string, diffID, blobsum d
 			return err
 		}
 	}
+	// update gc.root cause blob might be held by lease only
+	if _, err := s.opt.Content.Update(ctx, content.Info{
+		Digest: blobsum,
+		Labels: map[string]string{
+			"containerd.io/gc.root": time.Now().UTC().Format(time.RFC3339Nano),
+		},
+	}, "labels.containerd.io/gc.root"); err != nil {
+		return err
+	}
+
 	md, _ := s.opt.MetadataStore.Get(key)
 
 	v, err := metadata.NewValue(DiffPair{DiffID: diffID, Blobsum: blobsum})

vendor/github.com/moby/buildkit/source/local/local.go

@@ -133,6 +133,12 @@ func (ls *localSourceHandler) Snapshot(ctx context.Context) (out cache.Immutable
 
 	defer func() {
 		if retErr != nil && mutable != nil {
+			// on error remove the record as checksum update is in undefined state
+			cache.CachePolicyDefault(mutable)
+			if err := mutable.Metadata().Commit(); err != nil {
+				logrus.Errorf("failed to reset mutable cachepolicy: %v", err)
+			}
+			contenthash.ClearCacheContext(mutable.Metadata())
 			go mutable.Release(context.TODO())
 		}
 	}()

vendor/github.com/moby/buildkit/util/binfmt_misc/detect.go

@@ -21,6 +21,9 @@ func SupportedPlatforms() []string {
 		if p := "linux/arm64"; def != p && arm64Supported() == nil {
 			arr = append(arr, p)
 		}
+		if p := "linux/riscv64"; def != p && riscv64Supported() == nil {
+			arr = append(arr, p)
+		}
 		if !strings.HasPrefix(def, "linux/arm/") && armSupported() == nil {
 			arr = append(arr, "linux/arm/v7", "linux/arm/v6")
 		} else if def == "linux/arm/v7" {
@@ -47,6 +50,11 @@ func WarnIfUnsupported(pfs []string) {
 					printPlatfromWarning(p, err)
 				}
 			}
+			if p == "linux/riscv64" {
+				if err := riscv64Supported(); err != nil {
+					printPlatfromWarning(p, err)
+				}
+			}
 			if strings.HasPrefix(p, "linux/arm/v6") || strings.HasPrefix(p, "linux/arm/v7") {
 				if err := armSupported(); err != nil {
 					printPlatfromWarning(p, err)

vendor/github.com/moby/buildkit/util/binfmt_misc/riscv64_binary.go

@@ -0,0 +1,8 @@
+// +build !riscv64
+
+package binfmt_misc
+
+// This file is generated by running make inside the binfmt_misc package.
+// Do not edit manually.
+
+const Binaryriscv64 = "\x1f\x8b\x08\x00\x00\x00\x00\x00\x02\xff\xaa\x77\xf5\x71\x63\x62\x64\x64\x80\x01\x26\x86\xcf\x0c\x20\x5e\x05\x03\x44\xcc\x01\x2a\x3e\x03\x4a\xb3\x80\xc5\x2c\x18\x18\x19\x1c\x18\x98\x19\x98\xc0\xaa\x58\x19\x90\x01\x23\x0a\xdd\x02\xe5\xc1\x68\x06\x01\x08\x25\xcc\xca\xc0\x30\x99\xe3\x02\x6b\x31\x88\xa3\x57\x9c\x51\x5c\x52\x54\x92\x98\xc4\xa0\x57\x92\x5a\x51\xc2\x40\x05\xc0\x0d\x75\x01\x1b\x94\x0f\xf3\x4f\x05\x94\xcf\x83\xa6\x9e\x05\x8d\x0f\x52\xcd\x8c\xc5\x5c\x98\x3f\x04\xb1\xa8\x47\x06\x80\x00\x00\x00\xff\xff\x39\x41\xdf\xa1\x58\x01\x00\x00"

vendor/github.com/moby/buildkit/util/binfmt_misc/riscv64_check.go

@@ -0,0 +1,7 @@
+// +build !riscv64
+
+package binfmt_misc
+
+func riscv64Supported() error {
+	return check(Binaryriscv64)
+}

vendor/github.com/moby/buildkit/util/binfmt_misc/riscv64_check_riscv64.go

@@ -0,0 +1,7 @@
+// +build riscv64
+
+package binfmt_misc
+
+func riscv64Supported() error {
+	return nil
+}

vendor/github.com/moby/buildkit/util/imageutil/config.go

@@ -3,12 +3,17 @@ package imageutil
 import (
 	"context"
 	"encoding/json"
+	"fmt"
+	"sync"
+	"time"
 
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/leases"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/reference"
 	"github.com/containerd/containerd/remotes"
+	"github.com/moby/buildkit/util/leaseutil"
 	digest "github.com/opencontainers/go-digest"
 	specs "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
@@ -19,7 +24,19 @@ type ContentCache interface {
 	content.Provider
 }
 
-func Config(ctx context.Context, str string, resolver remotes.Resolver, cache ContentCache, p *specs.Platform) (digest.Digest, []byte, error) {
+var leasesMu sync.Mutex
+var leasesF []func(context.Context) error
+
+func CancelCacheLeases() {
+	leasesMu.Lock()
+	for _, f := range leasesF {
+		f(context.TODO())
+	}
+	leasesF = nil
+	leasesMu.Unlock()
+}
+
+func Config(ctx context.Context, str string, resolver remotes.Resolver, cache ContentCache, leaseManager leases.Manager, p *specs.Platform) (digest.Digest, []byte, error) {
 	// TODO: fix buildkit to take interface instead of struct
 	var platform platforms.MatchComparer
 	if p != nil {
@@ -32,6 +49,20 @@ func Config(ctx context.Context, str string, resolver remotes.Resolver, cache Co
 		return "", nil, errors.WithStack(err)
 	}
 
+	if leaseManager != nil {
+		ctx2, done, err := leaseutil.WithLease(ctx, leaseManager, leases.WithExpiration(5*time.Minute))
+		if err != nil {
+			return "", nil, errors.WithStack(err)
+		}
+		ctx = ctx2
+		defer func() {
+			// this lease is not deleted to allow other components to access manifest/config from cache. It will be deleted after 5 min deadline or on pruning inactive builder
+			leasesMu.Lock()
+			leasesF = append(leasesF, done)
+			leasesMu.Unlock()
+		}()
+	}
+
 	desc := specs.Descriptor{
 		Digest: ref.Digest(),
 	}
@@ -62,9 +93,14 @@ func Config(ctx context.Context, str string, resolver remotes.Resolver, cache Co
 		return readSchema1Config(ctx, ref.String(), desc, fetcher, cache)
 	}
 
+	children := childrenConfigHandler(cache, platform)
+	if m, ok := cache.(content.Manager); ok {
+		children = SetChildrenLabelsNonBlobs(m, children)
+	}
+
 	handlers := []images.Handler{
 		fetchWithoutRoot(remotes.FetchHandler(cache, fetcher)),
-		childrenConfigHandler(cache, platform),
+		children,
 	}
 	if err := images.Dispatch(ctx, images.Handlers(handlers...), nil, desc); err != nil {
 		return "", nil, err
@@ -171,3 +207,39 @@ func DetectManifestBlobMediaType(dt []byte) (string, error) {
 	}
 	return images.MediaTypeDockerSchema2ManifestList, nil
 }
+
+func SetChildrenLabelsNonBlobs(manager content.Manager, f images.HandlerFunc) images.HandlerFunc {
+	return func(ctx context.Context, desc specs.Descriptor) ([]specs.Descriptor, error) {
+		children, err := f(ctx, desc)
+		if err != nil {
+			return children, err
+		}
+
+		if len(children) > 0 {
+			info := content.Info{
+				Digest: desc.Digest,
+				Labels: map[string]string{},
+			}
+			fields := []string{}
+			for i, ch := range children {
+				switch ch.MediaType {
+				case images.MediaTypeDockerSchema2Layer, images.MediaTypeDockerSchema2LayerGzip, specs.MediaTypeImageLayer, specs.MediaTypeImageLayerGzip:
+					continue
+				default:
+				}
+
+				info.Labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", i)] = ch.Digest.String()
+				fields = append(fields, fmt.Sprintf("labels.containerd.io/gc.ref.content.%d", i))
+			}
+
+			if len(info.Labels) > 0 {
+				_, err := manager.Update(ctx, info, fields...)
+				if err != nil {
+					return nil, err
+				}
+			}
+		}
+
+		return children, err
+	}
+}

vendor/github.com/moby/buildkit/util/leaseutil/manager.go

@@ -0,0 +1,104 @@
+package leaseutil
+
+import (
+	"context"
+	"time"
+
+	"github.com/containerd/containerd/leases"
+	"github.com/containerd/containerd/metadata"
+	"github.com/containerd/containerd/namespaces"
+	bolt "go.etcd.io/bbolt"
+)
+
+func WithLease(ctx context.Context, ls leases.Manager, opts ...leases.Opt) (context.Context, func(context.Context) error, error) {
+	_, ok := leases.FromContext(ctx)
+	if ok {
+		return ctx, func(context.Context) error {
+			return nil
+		}, nil
+	}
+
+	l, err := ls.Create(ctx, append([]leases.Opt{leases.WithRandomID(), leases.WithExpiration(time.Hour)}, opts...)...)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	ctx = leases.WithLease(ctx, l.ID)
+	return ctx, func(ctx context.Context) error {
+		return ls.Delete(ctx, l)
+	}, nil
+}
+
+func NewManager(mdb *metadata.DB) leases.Manager {
+	return &local{db: mdb}
+}
+
+type local struct {
+	db *metadata.DB
+}
+
+func (l *local) Create(ctx context.Context, opts ...leases.Opt) (leases.Lease, error) {
+	var lease leases.Lease
+	if err := l.db.Update(func(tx *bolt.Tx) error {
+		var err error
+		lease, err = metadata.NewLeaseManager(tx).Create(ctx, opts...)
+		return err
+	}); err != nil {
+		return leases.Lease{}, err
+	}
+	return lease, nil
+}
+
+func (l *local) Delete(ctx context.Context, lease leases.Lease, opts ...leases.DeleteOpt) error {
+	var do leases.DeleteOptions
+	for _, opt := range opts {
+		if err := opt(ctx, &do); err != nil {
+			return err
+		}
+	}
+
+	if err := l.db.Update(func(tx *bolt.Tx) error {
+		return metadata.NewLeaseManager(tx).Delete(ctx, lease)
+	}); err != nil {
+		return err
+	}
+
+	return nil
+
+}
+
+func (l *local) List(ctx context.Context, filters ...string) ([]leases.Lease, error) {
+	var ll []leases.Lease
+	if err := l.db.View(func(tx *bolt.Tx) error {
+		var err error
+		ll, err = metadata.NewLeaseManager(tx).List(ctx, filters...)
+		return err
+	}); err != nil {
+		return nil, err
+	}
+	return ll, nil
+}
+
+func WithNamespace(lm leases.Manager, ns string) leases.Manager {
+	return &nsLM{Manager: lm, ns: ns}
+}
+
+type nsLM struct {
+	leases.Manager
+	ns string
+}
+
+func (l *nsLM) Create(ctx context.Context, opts ...leases.Opt) (leases.Lease, error) {
+	ctx = namespaces.WithNamespace(ctx, l.ns)
+	return l.Manager.Create(ctx, opts...)
+}
+
+func (l *nsLM) Delete(ctx context.Context, lease leases.Lease, opts ...leases.DeleteOpt) error {
+	ctx = namespaces.WithNamespace(ctx, l.ns)
+	return l.Manager.Delete(ctx, lease, opts...)
+}
+
+func (l *nsLM) List(ctx context.Context, filters ...string) ([]leases.Lease, error) {
+	ctx = namespaces.WithNamespace(ctx, l.ns)
+	return l.Manager.List(ctx, filters...)
+}