added preload status and cancel

pkg/fs/webdav.go

@@ -4,13 +4,14 @@ package fs
 
 import (
 	"context"
+	"net/http"
 	"os"
 
 	"golang.org/x/net/webdav"
 )
 
 type WebDavFile struct {
-	*File
+	http.File
 }
 
 func (*WebDavFile) Write(_ []byte) (int, error) {
@@ -41,7 +42,10 @@ func (w *WebDavFS) OpenFile(_ context.Context, name string, flags int, _ os.File
 		flags&os.O_TRUNC == os.O_TRUNC {
 		return nil, os.ErrPermission
 	}
-	f, err := w.fs.OpenFile(name)
+	f, err := w.fs.Open(name)
+	if err != nil {
+		return nil, err
+	}
 	return &WebDavFile{f}, err
 }