How to resize /overlay with little effert?

[hukangha]

I'm trying to install samba4 on my WRT1200AC V1 after upgrade to 19.07.2

seems samba4 is a large package, the opkg reports not enough space when installing samba4-server

This is what I have($ df -h):
Filesystem Size Used Available Use% Mounted on
/dev/root 2.5M 2.5M 0 100% /rom
tmpfs 250.0M 3.5M 246.5M 1% /tmp
/dev/ubi0_1 23.7M 6.8M 15.7M 30% /overlay
overlayfs:/overlay 23.7M 6.8M 15.7M 30% /
ubi1:syscfg 29.6M 548.0K 27.5M 2% /tmp/syscfg
tmpfs 512.0K 0 512.0K 0% /dev

Is there any way to squeeze some space to /overlay with minimal pain?
Or anyway to install a minimal-samba4?
Thanks

[eduperez]

As far as I know, /overlay is as big as it can be. I would consider using extroot instead.

[anomeome]

see if this meets your requirements.