原因是rename 方法无法在mount 点使用。
oldpath and newpath are not on the same mounted filesystem. (Linux permits a filesystem to be mounted at multiple
points, but rename() does not work across different mount points, even if the same filesystem is mounted on both.)
一般是使用拷贝，然后删除源文件方法解决。
c++ 调用rename 报错 Invalid cross-device link error
原文：https://www.cnblogs.com/mu-zhang/p/11269467.html