原文命令部分转自：iStoreOS x86根分区扩容 - 知乎 (zhihu.com)

扩容前提：需要给当前磁盘新增足够空间

# 执行parted
root@iStoreOS:~# parted

# 执行print命令，查看当前分区情况
(parted) print                                                            
Model: VMware Virtual disk (scsi)
Disk /dev/sda: 53.7GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type     File system  Flags
 1      262kB   134MB   134MB   primary  ext2         boot
 2      135MB   403MB   268MB   primary
 3      403MB   2551MB  2147MB  primary  ext4
 4      2551MB  17.2GB  14.6GB  primary  ext4

# 这里对分区3进行扩容，完成后退出
(parted) resizepart                                                       
Partition number? 3                                                       
Warning: Partition /dev/sda3 is being used. Are you sure you want to continue?
Yes/No? yes                                                               
End?  [2551MB]? 53.7G(这里的值根据实际情况进行设定) 
(parted) quit                                                             
Information: You may need to update /etc/fstab.

# 执行resize2fs对文件系统进行扩容
root@iStoreOS:~# resize2fs -p /dev/sda3
resize2fs 1.46.5 (30-Dec-2021)
Filesystem at /dev/sda3 is mounted on /overlay; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 7
The filesystem on /dev/sda3 is now 13008704 (4k) blocks long.

# 执行df -h可以看到分区大小已经更新
root@iStoreOS:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/sda3                48.8G      1.8G     46.9G   4% /overlay/upper/opt/docker