fix mounting ec volumes

weed/server/volume_grpc_erasure_coding.go

@@ -607,6 +607,14 @@ func (vs *VolumeServer) VolumeEcShardsToVolume(ctx context.Context, req *volume_
 		return nil, fmt.Errorf("WriteIdxFileFromEcIndex %s: %v", v.IndexBaseFileName(), err)
 	}
 
+	// mount the volume so it can be found by VolumeEcShardsGenerate
+	err = vs.store.MountVolume(needle.VolumeId(req.VolumeId))
+	if err != nil {
+		return nil, fmt.Errorf("failed to mount volume %d after EC decode: %v", req.VolumeId, err)
+	}
+
+	glog.V(1).Infof("VolumeEcShardsToVolume: successfully decoded and mounted volume %d", req.VolumeId)
+
 	return &volume_server_pb.VolumeEcShardsToVolumeResponse{}, nil
 }