Hyper-v vm, upgrading from 18.06 to 21.02, /overlay reduces to 98M, and unable to resize

Hi guys,

I made a snapshot of my vm, and followed this topic: https://openwrt.org/docs/guide-user/installation/openwrt_x86#resizing_filesystem, but it is unable to increase the /overlay.

This is the partitions after upgrading to 21.02:

root@VM-OpenWrt:~# df -hT
Filesystem           Type            Size      Used Available Use% Mounted on
/dev/root            squashfs        4.0M      4.0M         0 100% /rom
tmpfs                tmpfs         237.4M    668.0K    236.8M   0% /tmp
/dev/loop0           f2fs           98.1M     93.3M      4.8M  95% /overlay
overlayfs:/overlay   overlay        98.1M     93.3M      4.8M  95% /
/dev/sda1            ext4           15.7M      4.8M     10.7M  31% /boot
/dev/sda1            ext4           15.7M      4.8M     10.7M  31% /boot
tmpfs                tmpfs         512.0K         0    512.0K   0% /dev
root@VM-OpenWrt:~# losetup 
NAME       SIZELIMIT  OFFSET AUTOCLEAR RO BACK-FILE DIO LOG-SEC
/dev/loop0         0 4128768         1  0 /sda2       0     512

With unallocated free space:151M

Now, I increase the /dev/sda2 to 250M in cfdisk, and reboot vm:

    Device           Boot             Start          End      Sectors        Size      Id Type
>>  /dev/sda1        *                  512        33279        32768         16M      83 Linux          
    /dev/sda2                         33792       557407       523616      255.7M      83 Linux

Following the Resizing F2FS overlay:

root@VM-OpenWrt:~# LOOP="$(losetup -n -O NAME | sort | sed -n -e "1p")"
root@VM-OpenWrt:~# ROOT="$(losetup -n -O BACK-FILE ${LOOP} | sed -e "s|^|/dev|")"
root@VM-OpenWrt:~# OFFS="$(losetup -n -O OFFSET ${LOOP})"
root@VM-OpenWrt:~# LOOP="$(losetup -f)"
root@VM-OpenWrt:~# losetup -o ${OFFS} ${LOOP} ${ROOT}
root@VM-OpenWrt:~# fsck.f2fs -f ${LOOP}
Info: Force to fix corruption
Info: Segments per section = 1
Info: Sections per zone = 1
Info: sector size = 512
Info: total sectors = 515552 (251 MB)
Info: MKFS version
  "Linux version 5.4.154 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r16325-88151b8303)) #0 SMP Sun Oct 24 09:01:35 2021"
Info: FSCK version
  from "Linux version 5.4.154 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r16325-88151b8303)) #0 SMP Sun Oct 24 09:01:35 2021"
    to "Linux version 5.4.154 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r16325-88151b8303)) #0 SMP Sun Oct 24 09:01:35 2021"
Info: superblock features = 0 : 
Info: superblock encrypt level = 0, salt = 00000000000000000000000000000000
Info: total FS sectors = 204928 (100 MB)
Info: CKPT version = 5b1a0b8
Info: checkpoint state = 44 :  crc compacted_summary sudden-power-off

[FSCK] Unreachable nat entries                        [Ok..] [0x0]
[FSCK] SIT valid block bitmap checking                [Ok..]
[FSCK] Hard link checking for regular file            [Ok..] [0x0]
[FSCK] valid_block_count matching with CP             [Ok..] [0x2467]
[FSCK] valid_node_count matching with CP (de lookup)  [Ok..] [0x4db]
[FSCK] valid_node_count matching with CP (nat lookup) [Ok..] [0x4db]
[FSCK] valid_inode_count matched with CP              [Ok..] [0x4d9]
[FSCK] free segment_count matched with CP             [Ok..] [0x14]
[FSCK] next block offset is free                      [Ok..]
[FSCK] fixing SIT types
[FSCK] other corrupted bugs                           [Ok..]

Done: 0.167253 secs
root@VM-OpenWrt:~# mount ${LOOP} /mnt
root@VM-OpenWrt:~# umount ${LOOP}
root@VM-OpenWrt:~# resize.f2fs ${LOOP}
Info: Segments per section = 1
Info: Sections per zone = 1
Info: sector size = 512
Info: total sectors = 515552 (251 MB)
Info: MKFS version
  "Linux version 5.4.154 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r16325-88151b8303)) #0 SMP Sun Oct 24 09:01:35 2021"
Info: FSCK version
  from "Linux version 5.4.154 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r16325-88151b8303)) #0 SMP Sun Oct 24 09:01:35 2021"
    to "Linux version 5.4.154 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r16325-88151b8303)) #0 SMP Sun Oct 24 09:01:35 2021"
Info: superblock features = 0 : 
Info: superblock encrypt level = 0, salt = 00000000000000000000000000000000
Info: total FS sectors = 204928 (100 MB)
Info: CKPT version = 5b1a0ba
Info: Duplicate valid checkpoint to mirror position 1024 -> 512
Info: Write valid nat_bits in checkpoint
[FIX] (move_one_curseg_info:2799)  --> Move curseg[0] a -> b after 1000

[FIX] (move_one_curseg_info:2799)  --> Move curseg[1] 1 -> 16 after 1000

[FIX] (move_one_curseg_info:2799)  --> Move curseg[2] 17 -> 18 after 1000

[ASSERT] (move_one_curseg_info:2781) ret == 0
root@VM-OpenWrt:~#

After a reboot, nothing is changed, it's that something wrong? Anyone can give some advices? Thanks

root@VM-OpenWrt:~# df -hT
Filesystem           Type            Size      Used Available Use% Mounted on
/dev/root            squashfs        4.0M      4.0M         0 100% /rom
tmpfs                tmpfs         237.4M    172.0K    237.3M   0% /tmp
/dev/loop0           f2fs           98.1M     94.5M      3.6M  96% /overlay
overlayfs:/overlay   overlay        98.1M     94.5M      3.6M  96% /
/dev/sda1            ext4           15.7M      4.8M     10.7M  31% /boot
/dev/sda1            ext4           15.7M      4.8M     10.7M  31% /boot
tmpfs                tmpfs         512.0K         0    512.0K   0% /dev