diff --git a/backend/common.go b/backend/common.go
index b4ebf91..e3e8b18 100644
--- a/backend/common.go
+++ b/backend/common.go
@@ -19,6 +19,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io/fs"
+	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -120,3 +121,48 @@ func md5String(data []byte) string {
 	sum := md5.Sum(data)
 	return hex.EncodeToString(sum[:])
 }
+
+// MkdirAll is similar to os.MkdirAll but it will return ErrObjectParentIsFile
+// when appropriate
+func MkdirAll(path string, perm os.FileMode) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := os.Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return s3err.GetAPIError(s3err.ErrObjectParentIsFile)
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+
+	j := i
+	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
+		j--
+	}
+
+	if j > 1 {
+		// Create parent.
+		err = MkdirAll(path[:j-1], perm)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = os.Mkdir(path, perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := os.Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return s3err.GetAPIError(s3err.ErrObjectParentIsFile)
+	}
+	return nil
+}
diff --git a/backend/posix/posix.go b/backend/posix/posix.go
index 5e3c97e..fb3dfdc 100644
--- a/backend/posix/posix.go
+++ b/backend/posix/posix.go
@@ -376,7 +376,7 @@ func (p *Posix) CompleteMultipartUpload(_ context.Context, input *s3.CompleteMul
 	objname := filepath.Join(bucket, object)
 	dir := filepath.Dir(objname)
 	if dir != "" {
-		err = mkdirAll(dir, os.FileMode(0755), bucket, object)
+		err = backend.MkdirAll(dir, os.FileMode(0755))
 		if err != nil {
 			return nil, s3err.GetAPIError(s3err.ErrExistingObjectIsDirectory)
 		}
@@ -497,51 +497,6 @@ func isValidMeta(val string) bool {
 	return false
 }
 
-// mkdirAll is similar to os.MkdirAll but it will return ErrObjectParentIsFile
-// when appropriate
-func mkdirAll(path string, perm os.FileMode, bucket, object string) error {
-	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
-	dir, err := os.Stat(path)
-	if err == nil {
-		if dir.IsDir() {
-			return nil
-		}
-		return s3err.GetAPIError(s3err.ErrObjectParentIsFile)
-	}
-
-	// Slow path: make sure parent exists and then call Mkdir for path.
-	i := len(path)
-	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
-		i--
-	}
-
-	j := i
-	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
-		j--
-	}
-
-	if j > 1 {
-		// Create parent.
-		err = mkdirAll(path[:j-1], perm, bucket, object)
-		if err != nil {
-			return err
-		}
-	}
-
-	// Parent now exists; invoke Mkdir and use its result.
-	err = os.Mkdir(path, perm)
-	if err != nil {
-		// Handle arguments like "foo/." by
-		// double-checking that directory doesn't exist.
-		dir, err1 := os.Lstat(path)
-		if err1 == nil && dir.IsDir() {
-			return nil
-		}
-		return s3err.GetAPIError(s3err.ErrObjectParentIsFile)
-	}
-	return nil
-}
-
 func (p *Posix) AbortMultipartUpload(_ context.Context, mpu *s3.AbortMultipartUploadInput) error {
 	if mpu.Bucket == nil {
 		return s3err.GetAPIError(s3err.ErrInvalidBucketName)
@@ -1066,7 +1021,7 @@ func (p *Posix) PutObject(ctx context.Context, po *s3.PutObjectInput) (string, e
 			return "", s3err.GetAPIError(s3err.ErrDirectoryObjectContainsData)
 		}
 
-		err = mkdirAll(name, os.FileMode(0755), *po.Bucket, *po.Key)
+		err = backend.MkdirAll(name, os.FileMode(0755))
 		if err != nil {
 			return "", err
 		}
@@ -1102,7 +1057,7 @@ func (p *Posix) PutObject(ctx context.Context, po *s3.PutObjectInput) (string, e
 	}
 	dir := filepath.Dir(name)
 	if dir != "" {
-		err = mkdirAll(dir, os.FileMode(0755), *po.Bucket, *po.Key)
+		err = backend.MkdirAll(dir, os.FileMode(0755))
 		if err != nil {
 			return "", s3err.GetAPIError(s3err.ErrExistingObjectIsDirectory)
 		}
diff --git a/backend/scoutfs/scoutfs.go b/backend/scoutfs/scoutfs.go
index 9b24836..22ae864 100644
--- a/backend/scoutfs/scoutfs.go
+++ b/backend/scoutfs/scoutfs.go
@@ -203,7 +203,7 @@ func (s *ScoutFS) CompleteMultipartUpload(_ context.Context, input *s3.CompleteM
 	objname := filepath.Join(bucket, object)
 	dir := filepath.Dir(objname)
 	if dir != "" {
-		err = mkdirAll(dir, os.FileMode(0755), bucket, object)
+		err = backend.MkdirAll(dir, os.FileMode(0755))
 		if err != nil {
 			return nil, s3err.GetAPIError(s3err.ErrExistingObjectIsDirectory)
 		}
@@ -310,51 +310,6 @@ func isValidMeta(val string) bool {
 	return false
 }
 
-// mkdirAll is similar to os.MkdirAll but it will return ErrObjectParentIsFile
-// when appropriate
-func mkdirAll(path string, perm os.FileMode, bucket, object string) error {
-	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
-	dir, err := os.Stat(path)
-	if err == nil {
-		if dir.IsDir() {
-			return nil
-		}
-		return s3err.GetAPIError(s3err.ErrObjectParentIsFile)
-	}
-
-	// Slow path: make sure parent exists and then call Mkdir for path.
-	i := len(path)
-	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
-		i--
-	}
-
-	j := i
-	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
-		j--
-	}
-
-	if j > 1 {
-		// Create parent.
-		err = mkdirAll(path[:j-1], perm, bucket, object)
-		if err != nil {
-			return err
-		}
-	}
-
-	// Parent now exists; invoke Mkdir and use its result.
-	err = os.Mkdir(path, perm)
-	if err != nil {
-		// Handle arguments like "foo/." by
-		// double-checking that directory doesn't exist.
-		dir, err1 := os.Lstat(path)
-		if err1 == nil && dir.IsDir() {
-			return nil
-		}
-		return s3err.GetAPIError(s3err.ErrObjectParentIsFile)
-	}
-	return nil
-}
-
 func (s *ScoutFS) HeadObject(_ context.Context, input *s3.HeadObjectInput) (*s3.HeadObjectOutput, error) {
 	bucket := *input.Bucket
 	object := *input.Key