diff --git a/weed/server/filer_server_handlers.go b/weed/server/filer_server_handlers.go
index 0389e1e18..118646a04 100644
--- a/weed/server/filer_server_handlers.go
+++ b/weed/server/filer_server_handlers.go
@@ -58,8 +58,8 @@ func (fs *FilerServer) filerHandler(w http.ResponseWriter, r *http.Request) {
 			glog.V(4).Infof("wait because inflight data %d > %d", fs.inFlightDataSize, fs.option.ConcurrentUploadLimit)
 			fs.inFlightDataLimitCond.Wait()
 		}
-		atomic.AddInt64(&fs.inFlightDataSize, contentLength)
 		fs.inFlightDataLimitCond.L.Unlock()
+		atomic.AddInt64(&fs.inFlightDataSize, contentLength)
 		defer func() {
 			atomic.AddInt64(&fs.inFlightDataSize, -contentLength)
 			fs.inFlightDataLimitCond.Signal()
diff --git a/weed/server/volume_server_handlers.go b/weed/server/volume_server_handlers.go
index ed7807bb8..ff2eccc11 100644
--- a/weed/server/volume_server_handlers.go
+++ b/weed/server/volume_server_handlers.go
@@ -42,6 +42,7 @@ func (vs *VolumeServer) privateStoreHandler(w http.ResponseWriter, r *http.Reque
 			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":
 		stats.DeleteRequest()
@@ -55,8 +56,8 @@ func (vs *VolumeServer) privateStoreHandler(w http.ResponseWriter, r *http.Reque
 			glog.V(4).Infof("wait because inflight upload data %d > %d", vs.inFlightUploadDataSize, vs.concurrentUploadLimit)
 			vs.inFlightUploadDataLimitCond.Wait()
 		}
-		atomic.AddInt64(&vs.inFlightUploadDataSize, contentLength)
 		vs.inFlightUploadDataLimitCond.L.Unlock()
+		atomic.AddInt64(&vs.inFlightUploadDataSize, contentLength)
 		defer func() {
 			atomic.AddInt64(&vs.inFlightUploadDataSize, -contentLength)
 			vs.inFlightUploadDataLimitCond.Signal()
@@ -92,11 +93,14 @@ func (vs *VolumeServer) publicReadOnlyHandler(w http.ResponseWriter, r *http.Req
 		w.Header().Set("Access-Control-Allow-Credentials", "true")
 	}
 	switch r.Method {
-	case "GET":
-		stats.ReadRequest()
-		vs.GetOrHeadHandler(w, r)
-	case "HEAD":
+	case "GET", "HEAD":
 		stats.ReadRequest()
+		vs.inFlightDownloadDataLimitCond.L.Lock()
+		for vs.concurrentDownloadLimit != 0 && atomic.LoadInt64(&vs.inFlightDownloadDataSize) > vs.concurrentDownloadLimit {
+			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 "OPTIONS":
 		stats.ReadRequest()
diff --git a/weed/server/volume_server_handlers_read.go b/weed/server/volume_server_handlers_read.go
index ae3c0b53f..8602b0854 100644
--- a/weed/server/volume_server_handlers_read.go
+++ b/weed/server/volume_server_handlers_read.go
@@ -129,7 +129,6 @@ func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request)
 	onReadSizeFn := func(size types.Size) {
 		needleSize = size
 		atomic.AddInt64(&vs.inFlightDownloadDataSize, int64(needleSize))
-		vs.inFlightDownloadDataLimitCond.L.Unlock()
 	}
 	if hasVolume {
 		count, err = vs.store.ReadVolumeNeedle(volumeId, n, readOption, onReadSizeFn)