storagenode/console: diskSpaceInfo extended with overused diskspace, getDashboardData updated.

Change-Id: I44db26661a8dfb45b5d8e9fcb7511f63deb88cad

storagenode/console/diskspace.go

@@ -8,4 +8,5 @@ type DiskSpaceInfo struct {
 	Used      int64 `json:"used"`
 	Available int64 `json:"available"`
 	Trash     int64 `json:"trash"`
+	Overused  int64 `json:"overused"`
 }

storagenode/console/service.go

@@ -5,6 +5,7 @@ package console
 
 import (
 	"context"
+	"math"
 	"time"
 
 	"github.com/spacemonkeygo/monkit/v3"
@@ -210,6 +211,11 @@ func (s *Service) GetDashboardData(ctx context.Context) (_ *Dashboard, err error
 		Trash:     trash,
 	}
 
+	overused := s.allocatedDiskSpace.Int64() - pieceTotal - trash
+	if overused < 0 {
+		data.DiskSpace.Overused = int64(math.Abs(float64(overused)))
+	}
+
 	data.Bandwidth = BandwidthInfo{
 		Used: bandwidthUsage,
 	}