diff --git a/lib/readers/noclose.go b/lib/readers/noclose.go
index dc36e8be2..7516ef317 100644
--- a/lib/readers/noclose.go
+++ b/lib/readers/noclose.go
@@ -7,16 +7,29 @@ type noClose struct {
 	in io.Reader
 }
 
-// Read implements io.Closer by passing it straight on
+// Read implements io.Reader by passing it straight on
 func (nc noClose) Read(p []byte) (n int, err error) {
 	return nc.in.Read(p)
 }
 
+// noCloseWriterTo is a noClose which also forwards io.WriterTo
+type noCloseWriterTo struct {
+	noClose
+}
+
+// WriteTo implements io.WriterTo by passing it straight on
+func (nc noCloseWriterTo) WriteTo(w io.Writer) (n int64, err error) {
+	return nc.in.(io.WriterTo).WriteTo(w)
+}
+
 // NoCloser makes sure that the io.Reader passed in can't upgraded to
 // an io.Closer.
 //
 // This is for use with http.NewRequest to make sure the body doesn't
 // get upgraded to an io.Closer and the body closed unexpectedly.
+//
+// If in implements io.WriterTo then the returned reader does too so
+// that io.Copy can still use the more efficient path.
 func NoCloser(in io.Reader) io.Reader {
 	if in == nil {
 		return in
@@ -25,5 +38,8 @@ func NoCloser(in io.Reader) io.Reader {
 	if _, canClose := in.(io.Closer); !canClose {
 		return in
 	}
+	if _, canWriteTo := in.(io.WriterTo); canWriteTo {
+		return noCloseWriterTo{noClose{in: in}}
+	}
 	return noClose{in: in}
 }
diff --git a/lib/readers/noclose_test.go b/lib/readers/noclose_test.go
index e954d9c72..6bfa43b34 100644
--- a/lib/readers/noclose_test.go
+++ b/lib/readers/noclose_test.go
@@ -26,6 +26,14 @@ func (readClose) Close() (err error) {
 	return io.EOF
 }
 
+type readCloseWriteTo struct {
+	readClose
+}
+
+func (readCloseWriteTo) WriteTo(w io.Writer) (n int64, err error) {
+	return 42, errRead
+}
+
 func TestNoCloser(t *testing.T) {
 	assert.Equal(t, nil, NoCloser(nil))
 
@@ -41,4 +49,20 @@ func TestNoCloser(t *testing.T) {
 
 	_, err := nc.Read(nil)
 	assert.Equal(t, errRead, err)
+
+	_, hasWriteTo := nc.(io.WriterTo)
+	assert.False(t, hasWriteTo)
+
+	rcw := readCloseWriteTo{}
+	ncw := NoCloser(rcw)
+	assert.NotEqual(t, ncw, rcw)
+
+	_, hasClose = ncw.(io.Closer)
+	assert.False(t, hasClose)
+
+	wt, hasWriteTo := ncw.(io.WriterTo)
+	assert.True(t, hasWriteTo)
+	n, err := wt.WriteTo(nil)
+	assert.Equal(t, int64(42), n)
+	assert.Equal(t, errRead, err)
 }