XFS是centos7 操作系统默认软件系统，XFS只能扩大不能缩小
[root@localhost ~]# umount /home/ umount: /home: device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1))
如提示无法卸载，则是有进程占用/home，使用如下命令终止占用进程： [root@localhost ~]# fuser -m -k /home
-k 表示自动把霸占home分区的进程kill掉！