diff --git a/vendor.conf b/vendor.conf
index 15448572..54a56f0b 100644
--- a/vendor.conf
+++ b/vendor.conf
@@ -15,7 +15,7 @@ github.com/sirupsen/logrus v1.0.0
 github.com/containers/image 701221f0891d76aeac3f25912e6bb9f84e88de1c
 github.com/docker/docker-credential-helpers d68f9aeca33f5fd3f08eeae5e9d175edf4e731d1
 github.com/ostreedev/ostree-go master
-github.com/containers/storage 0d32dfce498e06c132c60dac945081bf44c22464
+github.com/containers/storage 477e551dd493e5c80999d3690d3a201fd26ba2f1
 github.com/containernetworking/cni v0.4.0
 google.golang.org/grpc v1.0.4 https://github.com/grpc/grpc-go
 github.com/opencontainers/selinux b29023b86e4a69d1b46b7e7b4e2b6fda03f0b9cd
diff --git a/vendor/github.com/containers/storage/drivers/aufs/aufs.go b/vendor/github.com/containers/storage/drivers/aufs/aufs.go
index aa0da7ad..c1cfabee 100644
--- a/vendor/github.com/containers/storage/drivers/aufs/aufs.go
+++ b/vendor/github.com/containers/storage/drivers/aufs/aufs.go
@@ -463,9 +463,9 @@ func (a *Driver) isParent(id, parent string) bool {
 
 // Diff produces an archive of the changes between the specified
 // layer and its parent layer which may be "".
-func (a *Driver) Diff(id, parent string) (io.ReadCloser, error) {
+func (a *Driver) Diff(id, parent, mountLabel string) (io.ReadCloser, error) {
 	if !a.isParent(id, parent) {
-		return a.naiveDiff.Diff(id, parent)
+		return a.naiveDiff.Diff(id, parent, mountLabel)
 	}
 
 	// AUFS doesn't need the parent layer to produce a diff.
@@ -502,9 +502,9 @@ func (a *Driver) applyDiff(id string, diff io.Reader) error {
 // DiffSize calculates the changes between the specified id
 // and its parent and returns the size in bytes of the changes
 // relative to its base filesystem directory.
-func (a *Driver) DiffSize(id, parent string) (size int64, err error) {
+func (a *Driver) DiffSize(id, parent, mountLabel string) (size int64, err error) {
 	if !a.isParent(id, parent) {
-		return a.naiveDiff.DiffSize(id, parent)
+		return a.naiveDiff.DiffSize(id, parent, mountLabel)
 	}
 	// AUFS doesn't need the parent layer to calculate the diff size.
 	return directory.Size(path.Join(a.rootPath(), "diff", id))
@@ -513,9 +513,9 @@ func (a *Driver) DiffSize(id, parent string) (size int64, err error) {
 // ApplyDiff extracts the changeset from the given diff into the
 // layer with the specified id and parent, returning the size of the
 // new layer in bytes.
-func (a *Driver) ApplyDiff(id, parent string, diff io.Reader) (size int64, err error) {
+func (a *Driver) ApplyDiff(id, parent, mountLabel string, diff io.Reader) (size int64, err error) {
 	if !a.isParent(id, parent) {
-		return a.naiveDiff.ApplyDiff(id, parent, diff)
+		return a.naiveDiff.ApplyDiff(id, parent, mountLabel, diff)
 	}
 
 	// AUFS doesn't need the parent id to apply the diff if it is the direct parent.
@@ -523,14 +523,14 @@ func (a *Driver) ApplyDiff(id, parent string, diff io.Reader) (size int64, err e
 		return
 	}
 
-	return a.DiffSize(id, parent)
+	return a.DiffSize(id, parent, mountLabel)
 }
 
 // Changes produces a list of changes between the specified layer
 // and its parent layer. If parent is "", then all changes will be ADD changes.
-func (a *Driver) Changes(id, parent string) ([]archive.Change, error) {
+func (a *Driver) Changes(id, parent, mountLabel string) ([]archive.Change, error) {
 	if !a.isParent(id, parent) {
-		return a.naiveDiff.Changes(id, parent)
+		return a.naiveDiff.Changes(id, parent, mountLabel)
 	}
 
 	// AUFS doesn't have snapshots, so we need to get changes from all parent
diff --git a/vendor/github.com/containers/storage/drivers/driver.go b/vendor/github.com/containers/storage/drivers/driver.go
index 56996478..615d93be 100644
--- a/vendor/github.com/containers/storage/drivers/driver.go
+++ b/vendor/github.com/containers/storage/drivers/driver.go
@@ -92,19 +92,19 @@ type ProtoDriver interface {
 type DiffDriver interface {
 	// Diff produces an archive of the changes between the specified
 	// layer and its parent layer which may be "".
-	Diff(id, parent string) (io.ReadCloser, error)
+	Diff(id, parent, mountLabel string) (io.ReadCloser, error)
 	// Changes produces a list of changes between the specified layer
 	// and its parent layer. If parent is "", then all changes will be ADD changes.
-	Changes(id, parent string) ([]archive.Change, error)
+	Changes(id, parent, mountLabel string) ([]archive.Change, error)
 	// ApplyDiff extracts the changeset from the given diff into the
 	// layer with the specified id and parent, returning the size of the
 	// new layer in bytes.
 	// The io.Reader must be an uncompressed stream.
-	ApplyDiff(id, parent string, diff io.Reader) (size int64, err error)
+	ApplyDiff(id, parent, mountLabel string, diff io.Reader) (size int64, err error)
 	// DiffSize calculates the changes between the specified id
 	// and its parent and returns the size in bytes of the changes
 	// relative to its base filesystem directory.
-	DiffSize(id, parent string) (size int64, err error)
+	DiffSize(id, parent, mountLabel string) (size int64, err error)
 }
 
 // Driver is the interface for layered/snapshot file system drivers.
diff --git a/vendor/github.com/containers/storage/drivers/fsdiff.go b/vendor/github.com/containers/storage/drivers/fsdiff.go
index 48a1f078..f74239cb 100644
--- a/vendor/github.com/containers/storage/drivers/fsdiff.go
+++ b/vendor/github.com/containers/storage/drivers/fsdiff.go
@@ -31,10 +31,10 @@ type NaiveDiffDriver struct {
 // NewNaiveDiffDriver returns a fully functional driver that wraps the
 // given ProtoDriver and adds the capability of the following methods which
 // it may or may not support on its own:
-//     Diff(id, parent string) (io.ReadCloser, error)
-//     Changes(id, parent string) ([]archive.Change, error)
-//     ApplyDiff(id, parent string, diff io.Reader) (size int64, err error)
-//     DiffSize(id, parent string) (size int64, err error)
+//     Diff(id, parent, mountLabel string) (io.ReadCloser, error)
+//     Changes(id, parent, mountLabel string) ([]archive.Change, error)
+//     ApplyDiff(id, parent, mountLabel string, diff io.Reader) (size int64, err error)
+//     DiffSize(id, parent, mountLabel string) (size int64, err error)
 func NewNaiveDiffDriver(driver ProtoDriver, uidMaps, gidMaps []idtools.IDMap) Driver {
 	return &NaiveDiffDriver{ProtoDriver: driver,
 		uidMaps: uidMaps,
@@ -43,11 +43,11 @@ func NewNaiveDiffDriver(driver ProtoDriver, uidMaps, gidMaps []idtools.IDMap) Dr
 
 // Diff produces an archive of the changes between the specified
 // layer and its parent layer which may be "".
-func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch io.ReadCloser, err error) {
+func (gdw *NaiveDiffDriver) Diff(id, parent, mountLabel string) (arch io.ReadCloser, err error) {
 	startTime := time.Now()
 	driver := gdw.ProtoDriver
 
-	layerFs, err := driver.Get(id, "")
+	layerFs, err := driver.Get(id, mountLabel)
 	if err != nil {
 		return nil, err
 	}
@@ -70,7 +70,7 @@ func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch io.ReadCloser, err err
 		}), nil
 	}
 
-	parentFs, err := driver.Get(parent, "")
+	parentFs, err := driver.Get(parent, mountLabel)
 	if err != nil {
 		return nil, err
 	}
@@ -101,10 +101,10 @@ func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch io.ReadCloser, err err
 
 // Changes produces a list of changes between the specified layer
 // and its parent layer. If parent is "", then all changes will be ADD changes.
-func (gdw *NaiveDiffDriver) Changes(id, parent string) ([]archive.Change, error) {
+func (gdw *NaiveDiffDriver) Changes(id, parent, mountLabel string) ([]archive.Change, error) {
 	driver := gdw.ProtoDriver
 
-	layerFs, err := driver.Get(id, "")
+	layerFs, err := driver.Get(id, mountLabel)
 	if err != nil {
 		return nil, err
 	}
@@ -113,7 +113,7 @@ func (gdw *NaiveDiffDriver) Changes(id, parent string) ([]archive.Change, error)
 	parentFs := ""
 
 	if parent != "" {
-		parentFs, err = driver.Get(parent, "")
+		parentFs, err = driver.Get(parent, mountLabel)
 		if err != nil {
 			return nil, err
 		}
@@ -126,11 +126,11 @@ func (gdw *NaiveDiffDriver) Changes(id, parent string) ([]archive.Change, error)
 // ApplyDiff extracts the changeset from the given diff into the
 // layer with the specified id and parent, returning the size of the
 // new layer in bytes.
-func (gdw *NaiveDiffDriver) ApplyDiff(id, parent string, diff io.Reader) (size int64, err error) {
+func (gdw *NaiveDiffDriver) ApplyDiff(id, parent, mountLabel string, diff io.Reader) (size int64, err error) {
 	driver := gdw.ProtoDriver
 
 	// Mount the root filesystem so we can apply the diff/layer.
-	layerFs, err := driver.Get(id, "")
+	layerFs, err := driver.Get(id, mountLabel)
 	if err != nil {
 		return
 	}
@@ -151,15 +151,15 @@ func (gdw *NaiveDiffDriver) ApplyDiff(id, parent string, diff io.Reader) (size i
 // DiffSize calculates the changes between the specified layer
 // and its parent and returns the size in bytes of the changes
 // relative to its base filesystem directory.
-func (gdw *NaiveDiffDriver) DiffSize(id, parent string) (size int64, err error) {
+func (gdw *NaiveDiffDriver) DiffSize(id, parent, mountLabel string) (size int64, err error) {
 	driver := gdw.ProtoDriver
 
-	changes, err := gdw.Changes(id, parent)
+	changes, err := gdw.Changes(id, parent, mountLabel)
 	if err != nil {
 		return
 	}
 
-	layerFs, err := driver.Get(id, "")
+	layerFs, err := driver.Get(id, mountLabel)
 	if err != nil {
 		return
 	}
diff --git a/vendor/github.com/containers/storage/drivers/overlay/overlay.go b/vendor/github.com/containers/storage/drivers/overlay/overlay.go
index 4974a94e..4458b679 100644
--- a/vendor/github.com/containers/storage/drivers/overlay/overlay.go
+++ b/vendor/github.com/containers/storage/drivers/overlay/overlay.go
@@ -142,16 +142,18 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, err
 	}
 
-	supportsDType, err := supportsOverlay(home, fsMagic, rootUID, rootGID)
-	if err != nil {
-		return nil, errors.Wrap(graphdriver.ErrNotSupported, "kernel does not support overlay fs")
-	}
-
 	// Create the driver home dir
 	if err := idtools.MkdirAllAs(path.Join(home, linkDir), 0700, rootUID, rootGID); err != nil && !os.IsExist(err) {
 		return nil, err
 	}
 
+	supportsDType, err := supportsOverlay(home, fsMagic, rootUID, rootGID)
+	if err != nil {
+		os.Remove(filepath.Join(home, linkDir))
+		os.Remove(home)
+		return nil, errors.Wrap(graphdriver.ErrNotSupported, "kernel does not support overlay fs")
+	}
+
 	if err := mount.MakePrivate(home); err != nil {
 		return nil, err
 	}
@@ -181,7 +183,7 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, fmt.Errorf("Storage option overlay.size only supported for backingFS XFS. Found %v", backingFs)
 	}
 
-	logrus.Debugf("backingFs=%s, projectQuotaSupported=%v", backingFs, projectQuotaSupported)
+	logrus.Debugf("backingFs=%s, projectQuotaSupported=%v, useNativeDiff=%v", backingFs, projectQuotaSupported, !useNaiveDiff(home))
 
 	return d, nil
 }
@@ -245,9 +247,7 @@ func supportsOverlay(home string, homeMagic graphdriver.FsMagic, rootUID, rootGI
 			return false, err
 		}
 		if !supportsDType {
-			logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay", backingFs))
-			// TODO: Will make fatal when CRI-O Has AMI built on RHEL7.4
-			// return nil, overlayutils.ErrDTypeNotSupported("overlay", backingFs)
+			return false, overlayutils.ErrDTypeNotSupported("overlay", backingFs)
 		}
 
 		// Try a test mount in the specific location we're looking at using.
@@ -426,11 +426,6 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr
 		return err
 	}
 
-	// if no parent directory, done
-	if parent == "" {
-		return nil
-	}
-
 	if err := idtools.MkdirAs(path.Join(dir, "work"), 0700, rootUID, rootGID); err != nil {
 		return err
 	}
@@ -438,6 +433,11 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr
 		return err
 	}
 
+	// if no parent directory, create a dummy lower directory and skip writing a "lowers" file
+	if parent == "" {
+		return idtools.MkdirAs(path.Join(dir, "empty"), 0700, rootUID, rootGID)
+	}
+
 	lower, err := d.getLower(parent)
 	if err != nil {
 		return err
@@ -558,11 +558,7 @@ func (d *Driver) Get(id, mountLabel string) (_ string, retErr error) {
 
 	diffDir := path.Join(dir, "diff")
 	lowers, err := ioutil.ReadFile(path.Join(dir, lowerFile))
-	if err != nil {
-		// If no lower, just return diff directory
-		if os.IsNotExist(err) {
-			return diffDir, nil
-		}
+	if err != nil && !os.IsNotExist(err) {
 		return "", err
 	}
 
@@ -590,6 +586,10 @@ func (d *Driver) Get(id, mountLabel string) (_ string, retErr error) {
 			newlowers = newlowers + ":" + lower
 		}
 	}
+	if len(lowers) == 0 {
+		newlowers = path.Join(dir, "empty")
+		lowers = []byte(newlowers)
+	}
 
 	mergedDir := path.Join(dir, "merged")
 	if count := d.ctr.Increment(mergedDir); count > 1 {
@@ -660,11 +660,7 @@ func (d *Driver) Put(id string) error {
 	if count := d.ctr.Decrement(mountpoint); count > 0 {
 		return nil
 	}
-	if _, err := ioutil.ReadFile(path.Join(dir, lowerFile)); err != nil {
-		// If no lower, we used the diff directory, so no work to do
-		if os.IsNotExist(err) {
-			return nil
-		}
+	if _, err := ioutil.ReadFile(path.Join(dir, lowerFile)); err != nil && !os.IsNotExist(err) {
 		return err
 	}
 	if err := unix.Unmount(mountpoint, unix.MNT_DETACH); err != nil {
@@ -701,9 +697,9 @@ func (d *Driver) isParent(id, parent string) bool {
 }
 
 // ApplyDiff applies the new layer into a root
-func (d *Driver) ApplyDiff(id string, parent string, diff io.Reader) (size int64, err error) {
+func (d *Driver) ApplyDiff(id, parent, mountLabel string, diff io.Reader) (size int64, err error) {
 	if !d.isParent(id, parent) {
-		return d.naiveDiff.ApplyDiff(id, parent, diff)
+		return d.naiveDiff.ApplyDiff(id, parent, mountLabel, diff)
 	}
 
 	applyDir := d.getDiffPath(id)
@@ -730,18 +726,18 @@ func (d *Driver) getDiffPath(id string) string {
 // DiffSize calculates the changes between the specified id
 // and its parent and returns the size in bytes of the changes
 // relative to its base filesystem directory.
-func (d *Driver) DiffSize(id, parent string) (size int64, err error) {
+func (d *Driver) DiffSize(id, parent, mountLabel string) (size int64, err error) {
 	if useNaiveDiff(d.home) || !d.isParent(id, parent) {
-		return d.naiveDiff.DiffSize(id, parent)
+		return d.naiveDiff.DiffSize(id, parent, mountLabel)
 	}
 	return directory.Size(d.getDiffPath(id))
 }
 
 // Diff produces an archive of the changes between the specified
 // layer and its parent layer which may be "".
-func (d *Driver) Diff(id, parent string) (io.ReadCloser, error) {
+func (d *Driver) Diff(id, parent, mountLabel string) (io.ReadCloser, error) {
 	if useNaiveDiff(d.home) || !d.isParent(id, parent) {
-		return d.naiveDiff.Diff(id, parent)
+		return d.naiveDiff.Diff(id, parent, mountLabel)
 	}
 
 	diffPath := d.getDiffPath(id)
@@ -756,9 +752,9 @@ func (d *Driver) Diff(id, parent string) (io.ReadCloser, error) {
 
 // Changes produces a list of changes between the specified layer
 // and its parent layer. If parent is "", then all changes will be ADD changes.
-func (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
+func (d *Driver) Changes(id, parent, mountLabel string) ([]archive.Change, error) {
 	if useNaiveDiff(d.home) || !d.isParent(id, parent) {
-		return d.naiveDiff.Changes(id, parent)
+		return d.naiveDiff.Changes(id, parent, mountLabel)
 	}
 	// Overlay doesn't have snapshots, so we need to get changes from all parent
 	// layers.
diff --git a/vendor/github.com/containers/storage/drivers/windows/windows.go b/vendor/github.com/containers/storage/drivers/windows/windows.go
index abe2ac43..e9e9f5c6 100644
--- a/vendor/github.com/containers/storage/drivers/windows/windows.go
+++ b/vendor/github.com/containers/storage/drivers/windows/windows.go
@@ -472,7 +472,7 @@ func (d *Driver) Cleanup() error {
 // Diff produces an archive of the changes between the specified
 // layer and its parent layer which may be "".
 // The layer should be mounted when calling this function
-func (d *Driver) Diff(id, parent string) (_ io.ReadCloser, err error) {
+func (d *Driver) Diff(id, parent, mountLabel string) (_ io.ReadCloser, err error) {
 	panicIfUsedByLcow()
 	rID, err := d.resolveID(id)
 	if err != nil {
@@ -509,7 +509,7 @@ func (d *Driver) Diff(id, parent string) (_ io.ReadCloser, err error) {
 // Changes produces a list of changes between the specified layer
 // and its parent layer. If parent is "", then all changes will be ADD changes.
 // The layer should not be mounted when calling this function.
-func (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
+func (d *Driver) Changes(id, parent, mountLabel string) ([]archive.Change, error) {
 	panicIfUsedByLcow()
 	rID, err := d.resolveID(id)
 	if err != nil {
@@ -565,7 +565,7 @@ func (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
 // layer with the specified id and parent, returning the size of the
 // new layer in bytes.
 // The layer should not be mounted when calling this function
-func (d *Driver) ApplyDiff(id, parent string, diff io.Reader) (int64, error) {
+func (d *Driver) ApplyDiff(id, parent, mountLabel string, diff io.Reader) (int64, error) {
 	panicIfUsedByLcow()
 	var layerChain []string
 	if parent != "" {
@@ -600,14 +600,14 @@ func (d *Driver) ApplyDiff(id, parent string, diff io.Reader) (int64, error) {
 // DiffSize calculates the changes between the specified layer
 // and its parent and returns the size in bytes of the changes
 // relative to its base filesystem directory.
-func (d *Driver) DiffSize(id, parent string) (size int64, err error) {
+func (d *Driver) DiffSize(id, parent, mountLabel string) (size int64, err error) {
 	panicIfUsedByLcow()
 	rPId, err := d.resolveID(parent)
 	if err != nil {
 		return
 	}
 
-	changes, err := d.Changes(id, rPId)
+	changes, err := d.Changes(id, rPId, mountLabel)
 	if err != nil {
 		return
 	}
diff --git a/vendor/github.com/containers/storage/layers.go b/vendor/github.com/containers/storage/layers.go
index f51406a0..a1be6eee 100644
--- a/vendor/github.com/containers/storage/layers.go
+++ b/vendor/github.com/containers/storage/layers.go
@@ -778,11 +778,11 @@ func (r *layerStore) findParentAndLayer(from, to string) (fromID string, toID st
 }
 
 func (r *layerStore) Changes(from, to string) ([]archive.Change, error) {
-	from, to, _, err := r.findParentAndLayer(from, to)
+	from, to, toLayer, err := r.findParentAndLayer(from, to)
 	if err != nil {
 		return nil, ErrLayerUnknown
 	}
-	return r.driver.Changes(to, from)
+	return r.driver.Changes(to, from, toLayer.MountLabel)
 }
 
 type simpleGetCloser struct {
@@ -855,7 +855,7 @@ func (r *layerStore) Diff(from, to string, options *DiffOptions) (io.ReadCloser,
 	}
 
 	if from != toLayer.Parent {
-		diff, err := r.driver.Diff(to, from)
+		diff, err := r.driver.Diff(to, from, toLayer.MountLabel)
 		if err != nil {
 			return nil, err
 		}
@@ -867,7 +867,7 @@ func (r *layerStore) Diff(from, to string, options *DiffOptions) (io.ReadCloser,
 		if !os.IsNotExist(err) {
 			return nil, err
 		}
-		diff, err := r.driver.Diff(to, from)
+		diff, err := r.driver.Diff(to, from, toLayer.MountLabel)
 		if err != nil {
 			return nil, err
 		}
@@ -906,11 +906,12 @@ func (r *layerStore) Diff(from, to string, options *DiffOptions) (io.ReadCloser,
 }
 
 func (r *layerStore) DiffSize(from, to string) (size int64, err error) {
-	from, to, _, err = r.findParentAndLayer(from, to)
+	var toLayer *Layer
+	from, to, toLayer, err = r.findParentAndLayer(from, to)
 	if err != nil {
 		return -1, ErrLayerUnknown
 	}
-	return r.driver.DiffSize(to, from)
+	return r.driver.DiffSize(to, from, toLayer.MountLabel)
 }
 
 func (r *layerStore) ApplyDiff(to string, diff io.Reader) (size int64, err error) {
@@ -950,7 +951,7 @@ func (r *layerStore) ApplyDiff(to string, diff io.Reader) (size int64, err error
 	if err != nil {
 		return -1, err
 	}
-	size, err = r.driver.ApplyDiff(layer.ID, layer.Parent, payload)
+	size, err = r.driver.ApplyDiff(layer.ID, layer.Parent, layer.MountLabel, payload)
 	if err != nil {
 		return -1, err
 	}
diff --git a/vendor/github.com/containers/storage/layers_ffjson.go b/vendor/github.com/containers/storage/layers_ffjson.go
index 8bec40e1..1d494e9d 100644
--- a/vendor/github.com/containers/storage/layers_ffjson.go
+++ b/vendor/github.com/containers/storage/layers_ffjson.go
@@ -1,5 +1,5 @@
 // Code generated by ffjson <https://github.com/pquerna/ffjson>. DO NOT EDIT.
-// source: layers.go
+// source: layers.go.  Hack to make this work on github.com
 
 package storage
 
diff --git a/vendor/github.com/containers/storage/pkg/truncindex/truncindex.go b/vendor/github.com/containers/storage/pkg/truncindex/truncindex.go
index 02610b8b..74776e65 100644
--- a/vendor/github.com/containers/storage/pkg/truncindex/truncindex.go
+++ b/vendor/github.com/containers/storage/pkg/truncindex/truncindex.go
@@ -77,10 +77,7 @@ func (idx *TruncIndex) addID(id string) error {
 func (idx *TruncIndex) Add(id string) error {
 	idx.Lock()
 	defer idx.Unlock()
-	if err := idx.addID(id); err != nil {
-		return err
-	}
-	return nil
+	return idx.addID(id)
 }
 
 // Delete removes an ID from the TruncIndex. If there are multiple IDs
@@ -128,8 +125,13 @@ func (idx *TruncIndex) Get(s string) (string, error) {
 	return "", ErrNotExist
 }
 
-// Iterate iterates over all stored IDs, and passes each of them to the given handler.
+// Iterate iterates over all stored IDs and passes each of them to the given
+// handler. Take care that the handler method does not call any public
+// method on truncindex as the internal locking is not reentrant/recursive
+// and will result in deadlock.
 func (idx *TruncIndex) Iterate(handler func(id string)) {
+	idx.Lock()
+	defer idx.Unlock()
 	idx.trie.Visit(func(prefix patricia.Prefix, item patricia.Item) error {
 		handler(string(prefix))
 		return nil