Hard disk related problem

Hello everyone
I just installed SLES 15 SP 1 on a Virtual Machine with 24 GB RAM and 350GB Hard Disk size.
Later I recognized hard disk size is not allocated to dev/sda and it was just using 80GB.
So I allocated to left space to dev/sda using gparted.
Now my /dev/sda is 350GB but /dev/mapper/system-root is still giving me an unsufficient space error.
Then I checked disk usage using df -h :

Which shows its not extended.
And here is fdisk results:

I’m sorry about asking simple question but how should I fix this?
Any kind of help will be appreciated.

@Gombo, Hi and welcome to the Forum :slight_smile:
I suspect the system is running btrfs along with snapshots and needs some maintenance…