mount: add grpc method to adjust quota

weed/mount/weedfs_quota.go

@@ -10,12 +10,14 @@ import (
 
 func (wfs *WFS) loopCheckQuota() {
 
-	if wfs.option.Quota <= 0 {
-		return
-	}
-
 	for {
 
+		time.Sleep(61 * time.Second)
+
+		if wfs.option.Quota <= 0 {
+			continue
+		}
+
 		err := wfs.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error {
 
 			request := &filer_pb.StatisticsRequest{
@@ -47,7 +49,6 @@ func (wfs *WFS) loopCheckQuota() {
 			glog.Warningf("read quota usage: %v", err)
 		}
 
-		time.Sleep(61 * time.Second)
 	}
 
 }