Need to exit waiting if request is was canceled

weed/server/volume_server_handlers.go

@@ -39,9 +39,15 @@ func (vs *VolumeServer) privateStoreHandler(w http.ResponseWriter, r *http.Reque
 		stats.ReadRequest()
 		vs.inFlightDownloadDataLimitCond.L.Lock()
 		for vs.concurrentDownloadLimit != 0 && atomic.LoadInt64(&vs.inFlightDownloadDataSize) > vs.concurrentDownloadLimit {
+			select {
+			case <-r.Context().Done():
+				glog.V(4).Infof("request cancelled from %s: %v", r.RemoteAddr, r.Context().Err())
+				return
+			default:
 				glog.V(4).Infof("wait because inflight download data %d > %d", vs.inFlightDownloadDataSize, vs.concurrentDownloadLimit)
 				vs.inFlightDownloadDataLimitCond.Wait()
 			}
+		}
 		vs.inFlightDownloadDataLimitCond.L.Unlock()
 		vs.GetOrHeadHandler(w, r)
 	case "DELETE":