如何缩小 VPS 上的根分区（无需卸载）。
df -h命令：
Filesystem Size Used Avail Use% Mounted on
udev 485M 0 485M 0% /dev
tmpfs 100M 7.9M 92M 8% /run
/dev/mapper/vg-lv_root 19G 1.2G 17G 7% /
tmpfs 496M 0 496M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 496M 0 496M 0% /sys/fs/cgroup
/dev/sda1 236M 37M 187M 17% /boot
tmpfs 100M 0 100M 0% /run/user/0
fdisk -l命令：
Disk /dev/sda: 20 GiB, 21474836480 bytes, 41943040 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xdfc30638
Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 499711 497664 243M 83 Linux
/dev/sda2 499712 20971519 20471808 9.8G 8e Linux LVM
/dev/sda3 20971520 41943039 20971520 10G 8e Linux LVM
Disk /dev/mapper/vg-lv_root: 18.8 GiB, 20136853504 bytes, 39329792 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/vg-lv_swap: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
我想从根分区创建 12 GB 的分区，然后根分区应该有 7 GB。
我知道我可能会丢失数据。