fix bug45

mainwindow.py

@@ -35,7 +35,7 @@ class MainWindow(QMainWindow):
 
         # 初始化管理器和操作类
         self.system_manager = SystemInfoManager()
-        self.disk_ops = DiskOperations()
+        self.disk_ops = DiskOperations(self.system_manager)
         self.raid_ops = RaidOperations()
         self.lvm_ops = LvmOperations()
 
@@ -208,12 +208,12 @@ class MainWindow(QMainWindow):
 
             if dev_data.get('children'):
                 logger.debug(f"磁盘 {disk_path} 存在现有分区，尝试计算下一个分区起始位置。")
-                calculated_start_mib = self.disk_ops.get_disk_next_partition_start_mib(disk_path)
-                if calculated_start_mib is None:
+                calculated_start_mib, largest_free_space_mib = self.disk_ops.get_disk_free_space_info_mib(disk_path, total_disk_mib)
+                if calculated_start_mib is None or largest_free_space_mib is None:
                     QMessageBox.critical(self, "错误", f"无法确定磁盘 {disk_path} 的分区起始位置。")
                     return
                 start_position_mib = calculated_start_mib
-                max_available_mib = total_disk_mib - start_position_mib
+                max_available_mib = largest_free_space_mib
                 if max_available_mib < 0:
                     max_available_mib = 0.0
             else: