diff --git a/hack/cpexp/cpexp.go b/hack/cpexp/cpexp.go
deleted file mode 100644
index c58d062871..0000000000
--- a/hack/cpexp/cpexp.go
+++ /dev/null
@@ -1,127 +0,0 @@
-package main
-
-import (
-	"log"
-	"os"
-	"path/filepath"
-	"strings"
-
-	"github.com/moby/buildkit/identity"
-	"github.com/moby/sys/mountinfo"
-	"github.com/pkg/errors"
-)
-
-const volumePath = "/abc/a"
-
-var rootfs string
-
-func main() {
-	if err := run(); err != nil {
-		log.Printf("error: %+v", err)
-	}
-}
-
-func run() error {
-	infos, err := mountinfo.GetMounts(nil)
-	if err != nil {
-		return err
-	}
-	hasVolume := false
-	for _, info := range infos {
-		if info.Mountpoint == "/" {
-			v, err := getOverlayRootfs(info)
-			if err != nil {
-				return err
-			}
-			rootfs = v
-		}
-
-		if info.Mountpoint == volumePath {
-			hasVolume = true
-		}
-		log.Printf("mount: %+v", info)
-	}
-	if !hasVolume {
-		return errors.Errorf("volume not found: %s", volumePath)
-	}
-
-	log.Printf("rootfs: %s", rootfs)
-
-	base := filepath.Base(rootfs)
-	if err := os.Symlink("/", filepath.Join(volumePath, base)); err != nil {
-		return err
-	}
-
-	// create duplicate volume path with symlink target
-	p := "/"
-	var volumeRoot string
-	for _, c := range strings.Split(filepath.Dir(volumePath), string(filepath.Separator)) {
-		if c == "" {
-			continue
-		}
-		if volumeRoot == "" {
-			volumeRoot = "/" + c
-			c += "_target"
-		}
-		p = filepath.Join(p, c)
-		if err := os.Mkdir(p, 0755); err != nil {
-			if os.IsExist(err) {
-				continue
-			}
-			return err
-		}
-		log.Printf("created: %s", p)
-	}
-	if err := os.Symlink(filepath.Dir(rootfs), filepath.Join(p, filepath.Base(volumePath))); err != nil {
-		return err
-	}
-
-	if err := os.Rename(volumeRoot, volumeRoot+"_old"); err != nil {
-		return err
-	}
-
-	for {
-		if _, err := os.Stat(volumeRoot); err != nil {
-			if os.IsNotExist(err) {
-				continue
-			}
-			return err
-		}
-		// log.Printf("detected: %s", volumeRoot)
-		break
-	}
-
-	for {
-		if err := os.Rename(volumeRoot+"_target", volumeRoot); err != nil {
-			if os.IsExist(err) {
-				if err := os.Rename(volumeRoot, volumeRoot+"_"+identity.NewID()); err != nil {
-					return err
-				}
-				continue
-			}
-			log.Printf("failed to rename: %s", err)
-		}
-		break
-	}
-
-	return nil
-}
-
-func getOverlayRootfs(info *mountinfo.Info) (string, error) {
-	if info.FSType != "overlay" {
-		return "", errors.Errorf("not overlay: %s", info.FSType)
-	}
-	for _, opt := range strings.Split(info.VFSOptions, ",") {
-		parts := strings.SplitN(opt, "=", 2)
-		if parts[0] == "workdir" {
-			return filepath.Join(filepath.Dir(parts[1]), "merged"), nil
-		}
-	}
-	return "", errors.Errorf("workdir not found: %s", info.VFSOptions)
-}
-
-// /var/lib/docker/overlay2/86fcb18db0e3774cfe3b9ed6fa526d4dffcb45ac3b26cbe99db6c2d08e6dfc0e/merged
-
-// merged/<sym>/dir1/dir2/
-
-// volume