@@ -26,7 +26,7 @@ github.com/imdario/mergo v0.3.6

 golang.org/x/sync 1d60e4601c6fd243af51cc01ddf169918a5407ca

 # buildkit

-github.com/moby/buildkit 520201006c9dc676da9cf9655337ac711f7f127d 

+github.com/moby/buildkit c7bb575343df0cbfeab8b5b28149630b8153fcc6

 github.com/tonistiigi/fsutil f567071bed2416e4d87d260d3162722651182317

 github.com/grpc-ecosystem/grpc-opentracing 8e809c8a86450a29b90dcc9efbf062d0fe6d9746

 github.com/opentracing/opentracing-go 1361b9cd60be79c4c3a7fa9841b3c132e40066a7

@@ -35,7 +35,7 @@ const (

 	localNameContext = "context"

 	historyComment   = "buildkit.dockerfile.v0"

-	DefaultCopyImage = "tonistiigi/copy:v0.1.5@sha256:eab89b76ffbb3c807663a67a41e8be31b8a0e362d7fb074a55bddace563a28bb"

+	DefaultCopyImage = "tonistiigi/copy:v0.1.7@sha256:9aab7d9ab369c6daf4831bf0653f7592110ab4b7e8a33fee2b9dca546e9d3089"

 )

 type ConvertOpt struct {

@@ -212,7 +212,7 @@ func Dockerfile2LLB(ctx context.Context, dt []byte, opt ConvertOpt) (*llb.State,

 				eg.Go(func() error {

 					ref, err := reference.ParseNormalizedNamed(d.stage.BaseName)

 					if err != nil {

-						return err

+						return errors.Wrapf(err, "failed to parse stage name %q", d.stage.BaseName)

 					}

 					platform := d.platform

 					if platform == nil {

@@ -653,7 +653,7 @@ func dispatchCopy(d *dispatchState, c instructions.SourcesAndDest, sourceState l

 	img := llb.Image(opt.copyImage, llb.MarkImageInternal, llb.Platform(opt.buildPlatforms[0]), WithInternalName("helper image for file operations"))

 	dest := path.Join(".", pathRelativeToWorkingDir(d.state, c.Dest()))

-	if c.Dest() == "." || c.Dest()[len(c.Dest())-1] == filepath.Separator {

+	if c.Dest() == "." || c.Dest() == "" || c.Dest()[len(c.Dest())-1] == filepath.Separator {

 		dest += string(filepath.Separator)

 	}

 	args := []string{"copy"}

@@ -136,7 +136,7 @@ func parseMount(value string) (*Mount, error) {

 				roAuto = false

 				continue

 			case "required":

-				if m.Type == "secret" {

+				if m.Type == "secret" || m.Type == "ssh" {

 					m.Required = true

 					continue

 				}

@@ -356,6 +356,9 @@ func (r *reference) ReadFile(ctx context.Context, req client.ReadRequest) ([]byt

 }

 func (r *reference) ReadDir(ctx context.Context, req client.ReadDirRequest) ([]*fstypes.Stat, error) {

+	if err := r.c.caps.Supports(pb.CapReadDir); err != nil {

+		return nil, err

+	}

 	rdr := &pb.ReadDirRequest{

 		DirPath:        req.Path,

 		IncludePattern: req.IncludePattern,

@@ -369,6 +372,9 @@ func (r *reference) ReadDir(ctx context.Context, req client.ReadDirRequest) ([]*

 }

 func (r *reference) StatFile(ctx context.Context, req client.StatRequest) (*fstypes.Stat, error) {

+	if err := r.c.caps.Supports(pb.CapStatFile); err != nil {

+		return nil, err

+	}

 	rdr := &pb.StatFileRequest{

 		Path: req.Path,

 		Ref:  r.id,

@@ -107,10 +107,21 @@ func (s *Snapshotter) GetBlob(ctx context.Context, key string) (digest.Digest, d

 // Checks that there is a blob in the content store.

 // If same blob has already been set then this is a noop.

 func (s *Snapshotter) SetBlob(ctx context.Context, key string, diffID, blobsum digest.Digest) error {

-	_, err := s.opt.Content.Info(ctx, blobsum)

+	info, err := s.opt.Content.Info(ctx, blobsum)

 	if err != nil {

 		return err

 	}

+	if _, ok := info.Labels["containerd.io/uncompressed"]; !ok {

+		labels := map[string]string{

+			"containerd.io/uncompressed": diffID.String(),

+		}

+		if _, err := s.opt.Content.Update(ctx, content.Info{

+			Digest: blobsum,

+			Labels: labels,

+		}, "labels.containerd.io/uncompressed"); err != nil {

+			return err

+		}

+	}

 	md, _ := s.opt.MetadataStore.Get(key)

 	v, err := metadata.NewValue(DiffPair{DiffID: diffID, Blobsum: blobsum})

@@ -211,10 +211,12 @@ func (ei *edgeIndex) getAllMatches(k *CacheKey) []string {

 			for _, d := range dd {

 				ll := CacheInfoLink{Input: Index(i), Digest: k.Digest(), Output: k.Output(), Selector: d.Selector}

 				for _, ckID := range d.CacheKey.CacheKey.indexIDs {

-					if l, ok := ei.items[ckID].links[ll]; ok {

-						if _, ok := l[m]; ok {

-							found = true

-							break

+					if item, ok := ei.items[ckID]; ok {

+						if l, ok := item.links[ll]; ok {

+							if _, ok := l[m]; ok {

+								found = true

+								break

+							}

 						}

 					}

 				}

@@ -302,7 +302,7 @@ func (e *execOp) getSSHMountable(ctx context.Context, m *pb.Mount) (cache.Mounta

 			return nil, nil

 		}

 		if st, ok := status.FromError(err); ok && st.Code() == codes.Unimplemented {

-			return nil, errors.Errorf("no ssh forwarded from the client")

+			return nil, errors.Errorf("no SSH key %q forwarded from the client", m.SSHOpt.ID)

 		}

 		return nil, err

 	}

@@ -3,11 +3,16 @@ package contentutil

 import (

 	"context"

 	"net/http"

+	"sync"

 	"github.com/containerd/containerd/content"

+	"github.com/containerd/containerd/errdefs"

 	"github.com/containerd/containerd/remotes"

 	"github.com/containerd/containerd/remotes/docker"

+	"github.com/docker/docker/pkg/locker"

+	digest "github.com/opencontainers/go-digest"

 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"

+	"github.com/pkg/errors"

 )

 func ProviderFromRef(ref string) (ocispec.Descriptor, content.Provider, error) {

@@ -38,11 +43,13 @@ func IngesterFromRef(ref string) (content.Ingester, error) {

 	}

 	return &ingester{

+		locker: locker.New(),

 		pusher: pusher,

 	}, nil

 }

 type ingester struct {

+	locker *locker.Locker

 	pusher remotes.Pusher

 }

@@ -53,5 +60,38 @@ func (w *ingester) Writer(ctx context.Context, opts ...content.WriterOpt) (conte

 			return nil, err

 		}

 	}

-	return w.pusher.Push(ctx, wo.Desc)

+	if wo.Ref == "" {

+		return nil, errors.Wrap(errdefs.ErrInvalidArgument, "ref must not be empty")

+	}

+	w.locker.Lock(wo.Ref)

+	var once sync.Once

+	unlock := func() {

+		once.Do(func() {

+			w.locker.Unlock(wo.Ref)

+		})

+	}

+	writer, err := w.pusher.Push(ctx, wo.Desc)

+	if err != nil {

+		return nil, err

+	}

+	return &lockedWriter{unlock: unlock, Writer: writer}, nil

+}

+

+type lockedWriter struct {

+	unlock func()

+	content.Writer

+}

+

+func (w *lockedWriter) Commit(ctx context.Context, size int64, expected digest.Digest, opts ...content.Opt) error {

+	err := w.Writer.Commit(ctx, size, expected, opts...)

+	if err == nil {

+		w.unlock()

+	}

+	return err

+}

+

+func (w *lockedWriter) Close() error {

+	err := w.Writer.Close()

+	w.unlock()

+	return err

 }