func (s *erasureSets) getDiskMap() map[Endpoint]StorageAPI {
	diskMap := make(map[Endpoint]StorageAPI)

	s.erasureDisksMu.RLock()
	defer s.erasureDisksMu.RUnlock()

	for i := 0; i < s.setCount; i++ {
		for j := 0; j < s.setDriveCount; j++ {
			disk := s.erasureDisks[i][j]
			if disk == OfflineDisk {
				continue
			}
			if !disk.IsOnline() {
				continue
			}
			diskMap[disk.Endpoint()] = disk
		}
	}
	return diskMap