diff --git a/layers.go b/layers.go
index 0f0fc2b22f..6516917093 100644
--- a/layers.go
+++ b/layers.go
@@ -314,9 +314,8 @@ type rwLayerStore interface {
 	// applies its changes to a specified layer.
 	ApplyDiff(to string, diff io.Reader) (int64, error)
 
-	// ApplyDiffWithDiffer applies the changes through the differ callback function.
-	// If to is the empty string, then a staging directory is created by the driver.
-	ApplyDiffWithDiffer(to string, options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error)
+	// applyDiffWithDifferNoLock applies the changes through the differ callback function.
+	applyDiffWithDifferNoLock(options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error)
 
 	// CleanupStagingDirectory cleanups the staging directory.  It can be used to cleanup the staging directory on errors
 	CleanupStagingDirectory(stagingDirectory string) error
@@ -2543,37 +2542,14 @@ func (r *layerStore) applyDiffFromStagingDirectory(id string, diffOutput *driver
 	return err
 }
 
-// Requires startWriting.
-func (r *layerStore) ApplyDiffWithDiffer(to string, options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error) {
+// It must be called without any c/storage locks held to allow differ to make c/storage calls.
+func (r *layerStore) applyDiffWithDifferNoLock(options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error) {
 	ddriver, ok := r.driver.(drivers.DriverWithDiffer)
 	if !ok {
 		return nil, ErrNotSupported
 	}
 
-	if to == "" {
-		output, err := ddriver.ApplyDiffWithDiffer("", "", options, differ)
-		return &output, err
-	}
-
-	layer, ok := r.lookup(to)
-	if !ok {
-		return nil, ErrLayerUnknown
-	}
-	if options == nil {
-		options = &drivers.ApplyDiffWithDifferOpts{
-			ApplyDiffOpts: drivers.ApplyDiffOpts{
-				Mappings:   r.layerMappings(layer),
-				MountLabel: layer.MountLabel,
-			},
-		}
-	}
-	output, err := ddriver.ApplyDiffWithDiffer(layer.ID, layer.Parent, options, differ)
-	if err != nil {
-		return nil, err
-	}
-	layer.UIDs = output.UIDs
-	layer.GIDs = output.GIDs
-	err = r.saveFor(layer)
+	output, err := ddriver.ApplyDiffWithDiffer("", "", options, differ)
 	return &output, err
 }
 
diff --git a/pkg/chunked/cache_linux.go b/pkg/chunked/cache_linux.go
index 0f6b7b63b8..a7dc18be42 100644
--- a/pkg/chunked/cache_linux.go
+++ b/pkg/chunked/cache_linux.go
@@ -82,6 +82,7 @@ func (c *layer) release() {
 		if err := unix.Munmap(c.mmapBuffer); err != nil {
 			logrus.Warnf("Error Munmap: layer %q: %v", c.id, err)
 		}
+		c.mmapBuffer = nil
 	}
 }
 
@@ -110,7 +111,7 @@ func getLayersCacheRef(store storage.Store) *layersCache {
 		cache.refs++
 		return cache
 	}
-	cache := &layersCache{
+	cache = &layersCache{
 		store: store,
 		refs:  1,
 	}
@@ -779,14 +780,14 @@ func (c *layersCache) findDigestInternal(digest string) (string, string, int64,
 		return "", "", -1, nil
 	}
 
+	c.mutex.RLock()
+	defer c.mutex.RUnlock()
+
 	binaryDigest, err := makeBinaryDigest(digest)
 	if err != nil {
 		return "", "", 0, err
 	}
 
-	c.mutex.RLock()
-	defer c.mutex.RUnlock()
-
 	for _, layer := range c.layers {
 		if !layer.cacheFile.bloomFilter.maybeContains(binaryDigest) {
 			continue
diff --git a/store.go b/store.go
index e1890f90ed..692bf35314 100644
--- a/store.go
+++ b/store.go
@@ -3110,16 +3110,18 @@ func (s *store) CleanupStagedLayer(diffOutput *drivers.DriverWithDifferOutput) e
 }
 
 func (s *store) PrepareStagedLayer(options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error) {
-	return s.ApplyDiffWithDiffer("", options, differ)
+	rlstore, err := s.getLayerStore()
+	if err != nil {
+		return nil, err
+	}
+	return rlstore.applyDiffWithDifferNoLock(options, differ)
 }
 
 func (s *store) ApplyDiffWithDiffer(to string, options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error) {
-	return writeToLayerStore(s, func(rlstore rwLayerStore) (*drivers.DriverWithDifferOutput, error) {
-		if to != "" && !rlstore.Exists(to) {
-			return nil, ErrLayerUnknown
-		}
-		return rlstore.ApplyDiffWithDiffer(to, options, differ)
-	})
+	if to != "" {
+		return nil, fmt.Errorf("ApplyDiffWithDiffer does not support non-empty 'layer' parameter")
+	}
+	return s.PrepareStagedLayer(options, differ)
 }
 
 func (s *store) DifferTarget(id string) (string, error) {