storage: use the TOC digest for partial layers

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

storage/storage_dest.go

@@ -328,6 +328,14 @@ func (s *storageImageDestination) tryReusingBlobAsPending(digest digest.Digest,
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
+	toc, err := chunked.GetTOCDigest(options.Annotations)
+	if err != nil {
+		return false, private.ReusedBlob{}, err
+	}
+	if toc != nil {
+		digest = *toc
+	}
+
 	if options.SrcRef != nil {
 		// Check if we have the layer in the underlying additional layer store.
 		aLayer, err := s.imageRef.transport.store.LookupAdditionalLayer(digest, options.SrcRef.String())
@@ -564,7 +572,10 @@ func (s *storageImageDestination) getDiffIDFromDigest(uncompressedDigest digest.
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
-	d, found := s.diffOutputs[uncompressedDigest]; found {
+	if d, found := s.diffOutputs[uncompressedDigest]; found {
+		return d.TOCDigest, found
+	}
+	d, found := s.blobDiffIDs[uncompressedDigest]
 	return d, found
 }