some changes to prepare fix after failed reads

weed/server/volume_server_handlers_read.go

@@ -93,6 +93,10 @@ func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request)
 	} else if hasEcVolume {
 		count, err = vs.store.ReadEcShardNeedle(volumeId, n)
 	}
+	if err != nil && err != storage.ErrorDeleted && r.FormValue("type") != "replicate" && hasVolume {
+		glog.V(4).Infoln("read needle: %v", err)
+		// start to fix it from other replicas, if not deleted and hasVolume and is not a replicated request
+	}
 	// glog.V(4).Infoln("read bytes", count, "error", err)
 	if err != nil || count < 0 {
 		glog.V(3).Infof("read %s isNormalVolume %v error: %v", r.URL.Path, hasVolume, err)