缩容

目标分区/dev/centos/home，挂载点/home
xfs文件系统只能扩大，不能缩小，要通过别的手段实现缩容
首先备份目标分区

xfsdump -f /home.xfsdump /home

卸载目标分区

umount /home

调整目标分区的lv容量，这里缩成5G

[root@centos /]# lvreduce -L 5G /dev/centos/home
  WARNING: Reducing active logical volume to 5.00 GiB.
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce centos/home? [y/n]: y
  Size of logical volume centos/home changed from <61.12 GiB (15646 extents) to 5.00 GiB (1280 extents).
  Logical volume centos/home successfully resized.

重新格式化分区，加-f强制格式化

mkfs.xfs /dev/centos/home -f

挂载目标分区

mount /dev/centos/home /home

使用xfsrestore恢复文件

xfsrestore -f /home.xfsdump /home

扩容

目标分区/dev/cetnos/root，挂载点/
首先扩容分区的lv，可以参考红帽的 文档

[root@centos /]# lvextend -l +100%FREE /dev/centos/root
  Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 106.12 GiB (27167 extents).
  Logical volume centos/root successfully resized.
You have mail in /var/spool/mail/root

然后扩容xfs

xfs_growfs /