mount: retry for directory listing with filer

related to https://github.com/chrislusf/seaweedfs/issues/1530

weed/filesys/meta_cache/meta_cache_init.go

@@ -3,6 +3,8 @@ package meta_cache
 import (
 	"context"
 	"fmt"
+	"strings"
+	"time"
 
 	"github.com/chrislusf/seaweedfs/weed/filer"
 	"github.com/chrislusf/seaweedfs/weed/glog"
@@ -16,6 +18,7 @@ func EnsureVisited(mc *MetaCache, client filer_pb.FilerClient, dirPath util.Full
 
 		glog.V(4).Infof("ReadDirAllEntries %s ...", path)
 
+		for waitTime := time.Second; waitTime < filer.ReadWaitTime; waitTime += waitTime / 2 {
 			err = filer_pb.ReadDirAllEntries(client, dirPath, "", func(pbEntry *filer_pb.Entry, isLast bool) error {
 				entry := filer.FromPbEntry(string(dirPath), pbEntry)
 				if err := mc.doInsertEntry(context.Background(), entry); err != nil {
@@ -27,8 +30,16 @@ func EnsureVisited(mc *MetaCache, client filer_pb.FilerClient, dirPath util.Full
 				}
 				return nil
 			})
-		if err != nil {
+			if err == nil {
+				break
+			}
+			if strings.Contains(err.Error(), "transport: ") {
+				glog.V(0).Infof("ReadDirAllEntries %s: %v. Retry in %v", path, err, waitTime)
+				time.Sleep(waitTime)
+				continue
+			}
 			err = fmt.Errorf("list %s: %v", dirPath, err)
+			break
 		}
 		return
 	})