diff --git a/core/commands/add.go b/core/commands/add.go
index 3022afc07..44f3a5052 100644
--- a/core/commands/add.go
+++ b/core/commands/add.go
@@ -279,13 +279,13 @@ You can now check what blocks have been created by:
 		fileAdder.Silent = silent
 		fileAdder.RawLeaves = rawblks
 		fileAdder.NoCopy = nocopy
-		fileAdder.Prefix = &prefix
+		fileAdder.CidBuilder = &prefix
 
 		if hash {
 			md := dagtest.Mock()
 			emptyDirNode := ft.EmptyDirNode()
 			// Use the same prefix for the "empty" MFS root as for the file adder.
-			emptyDirNode.SetCidBuilder(fileAdder.Prefix)
+			emptyDirNode.SetCidBuilder(fileAdder.CidBuilder)
 			mr, err := mfs.NewRoot(req.Context, md, emptyDirNode, nil)
 			if err != nil {
 				res.SetError(err, cmdkit.ErrNormal)
diff --git a/core/commands/files.go b/core/commands/files.go
index ad36875ec..6e0a4d4cd 100644
--- a/core/commands/files.go
+++ b/core/commands/files.go
@@ -868,9 +868,9 @@ Examples:
 		root := n.FilesRoot
 
 		err = mfs.Mkdir(root, dirtomake, mfs.MkdirOpts{
-			Mkparents: dashp,
-			Flush:     flush,
-			Prefix:    prefix,
+			Mkparents:  dashp,
+			Flush:      flush,
+			CidBuilder: prefix,
 		})
 		if err != nil {
 			res.SetError(err, cmdkit.ErrNormal)
@@ -958,8 +958,8 @@ Change the cid version or hash function of the root node of a given path.
 	},
 }
 
-func updatePath(rt *mfs.Root, pth string, prefix cid.Builder, flush bool) error {
-	if prefix == nil {
+func updatePath(rt *mfs.Root, pth string, builder cid.Builder, flush bool) error {
+	if builder == nil {
 		return nil
 	}
 
@@ -970,7 +970,7 @@ func updatePath(rt *mfs.Root, pth string, prefix cid.Builder, flush bool) error
 
 	switch n := nd.(type) {
 	case *mfs.Directory:
-		n.SetPrefix(prefix)
+		n.SetCidBuilder(builder)
 	default:
 		return fmt.Errorf("can only update directories")
 	}
@@ -1146,7 +1146,7 @@ func getPrefix(req oldcmds.Request) (cid.Builder, error) {
 	return &prefix, nil
 }
 
-func getFileHandle(r *mfs.Root, path string, create bool, prefix cid.Builder) (*mfs.File, error) {
+func getFileHandle(r *mfs.Root, path string, create bool, builder cid.Builder) (*mfs.File, error) {
 	target, err := mfs.Lookup(r, path)
 	switch err {
 	case nil:
@@ -1172,12 +1172,12 @@ func getFileHandle(r *mfs.Root, path string, create bool, prefix cid.Builder) (*
 		if !ok {
 			return nil, fmt.Errorf("%s was not a directory", dirname)
 		}
-		if prefix == nil {
-			prefix = pdir.GetPrefix()
+		if builder == nil {
+			builder = pdir.GetCidBuilder()
 		}
 
 		nd := dag.NodeWithData(ft.FilePBData(nil, 0))
-		nd.SetCidBuilder(prefix)
+		nd.SetCidBuilder(builder)
 		err = pdir.AddChild(fname, nd)
 		if err != nil {
 			return nil, err
diff --git a/core/coreunix/add.go b/core/coreunix/add.go
index 732755f43..2ca089ff4 100644
--- a/core/coreunix/add.go
+++ b/core/coreunix/add.go
@@ -89,7 +89,7 @@ type Adder struct {
 	mroot      *mfs.Root
 	unlocker   bstore.Unlocker
 	tempRoot   *cid.Cid
-	Prefix     cid.Builder
+	CidBuilder cid.Builder
 	liveNodes  uint64
 }
 
@@ -98,7 +98,7 @@ func (adder *Adder) mfsRoot() (*mfs.Root, error) {
 		return adder.mroot, nil
 	}
 	rnode := unixfs.EmptyDirNode()
-	rnode.SetCidBuilder(adder.Prefix)
+	rnode.SetCidBuilder(adder.CidBuilder)
 	mr, err := mfs.NewRoot(adder.ctx, adder.dagService, rnode, nil)
 	if err != nil {
 		return nil, err
@@ -124,7 +124,7 @@ func (adder *Adder) add(reader io.Reader) (ipld.Node, error) {
 		RawLeaves:  adder.RawLeaves,
 		Maxlinks:   ihelper.DefaultLinksPerBlock,
 		NoCopy:     adder.NoCopy,
-		CidBuilder: adder.Prefix,
+		CidBuilder: adder.CidBuilder,
 	}
 
 	if adder.Trickle {
@@ -384,9 +384,9 @@ func (adder *Adder) addNode(node ipld.Node, path string) error {
 	dir := gopath.Dir(path)
 	if dir != "." {
 		opts := mfs.MkdirOpts{
-			Mkparents: true,
-			Flush:     false,
-			Prefix:    adder.Prefix,
+			Mkparents:  true,
+			Flush:      false,
+			CidBuilder: adder.CidBuilder,
 		}
 		if err := mfs.Mkdir(mr, dir, opts); err != nil {
 			return err
@@ -449,7 +449,7 @@ func (adder *Adder) addFile(file files.File) error {
 		}
 
 		dagnode := dag.NodeWithData(sdata)
-		dagnode.SetCidBuilder(adder.Prefix)
+		dagnode.SetCidBuilder(adder.CidBuilder)
 		err = adder.dagService.Add(adder.ctx, dagnode)
 		if err != nil {
 			return err
@@ -488,9 +488,9 @@ func (adder *Adder) addDir(dir files.File) error {
 		return err
 	}
 	err = mfs.Mkdir(mr, dir.FileName(), mfs.MkdirOpts{
-		Mkparents: true,
-		Flush:     false,
-		Prefix:    adder.Prefix,
+		Mkparents:  true,
+		Flush:      false,
+		CidBuilder: adder.CidBuilder,
 	})
 	if err != nil {
 		return err
diff --git a/mfs/dir.go b/mfs/dir.go
index eafff388d..ea5e9c847 100644
--- a/mfs/dir.go
+++ b/mfs/dir.go
@@ -63,14 +63,14 @@ func NewDirectory(ctx context.Context, name string, node ipld.Node, parent child
 	}, nil
 }
 
-// GetPrefix gets the CID prefix of the root node
-func (d *Directory) GetPrefix() cid.Builder {
+// GetCidBuilder gets the CID builder of the root node
+func (d *Directory) GetCidBuilder() cid.Builder {
 	return d.unixfsDir.GetCidBuilder()
 }
 
-// SetPrefix sets the CID prefix
-func (d *Directory) SetPrefix(prefix cid.Builder) {
-	d.unixfsDir.SetCidBuilder(prefix)
+// SetCidBuilder sets the CID builder
+func (d *Directory) SetCidBuilder(b cid.Builder) {
+	d.unixfsDir.SetCidBuilder(b)
 }
 
 // closeChild updates the child by the given name to the dag node 'nd'
@@ -307,7 +307,7 @@ func (d *Directory) Mkdir(name string) (*Directory, error) {
 	}
 
 	ndir := ft.EmptyDirNode()
-	ndir.SetCidBuilder(d.GetPrefix())
+	ndir.SetCidBuilder(d.GetCidBuilder())
 
 	err = d.dserv.Add(d.ctx, ndir)
 	if err != nil {
diff --git a/mfs/ops.go b/mfs/ops.go
index 4bed33ed0..8b14abc8d 100644
--- a/mfs/ops.go
+++ b/mfs/ops.go
@@ -99,9 +99,9 @@ func PutNode(r *Root, path string, nd ipld.Node) error {
 
 // MkdirOpts is used by Mkdir
 type MkdirOpts struct {
-	Mkparents bool
-	Flush     bool
-	Prefix    cid.Builder
+	Mkparents  bool
+	Flush      bool
+	CidBuilder cid.Builder
 }
 
 // Mkdir creates a directory at 'path' under the directory 'd', creating
@@ -136,8 +136,8 @@ func Mkdir(r *Root, pth string, opts MkdirOpts) error {
 			if err != nil {
 				return err
 			}
-			if opts.Prefix != nil {
-				mkd.SetPrefix(opts.Prefix)
+			if opts.CidBuilder != nil {
+				mkd.SetCidBuilder(opts.CidBuilder)
 			}
 			fsn = mkd
 		} else if err != nil {
@@ -157,8 +157,8 @@ func Mkdir(r *Root, pth string, opts MkdirOpts) error {
 			return err
 		}
 	}
-	if opts.Prefix != nil {
-		final.SetPrefix(opts.Prefix)
+	if opts.CidBuilder != nil {
+		final.SetCidBuilder(opts.CidBuilder)
 	}
 
 	if opts.Flush {