Handle shrinking partition to a smaller size than possible

[nteodosio]

Is there an existing issue for this?

• I have searched the existing issues and found none matching what I'm reporting.

Bug Description

In the manual installation of Ubuntu (24.04) one can resize existing partitions (in order to fit Ubuntu's).

I accidentally set the desired new size to be smaller than the occupied space of said parition. The partitioner did not complain and did follow to the last step, which gave a generic error ("something went wrong try again" or something like it).

Then in the log viewport I found:

resize2fs: New size smaller than minimum (17606246)

I opened Gparted from the live system and resized it manually and reopened the installer, but it still held that grudge against me and did not let me retry the installation, so I had to reboot the live media and then install Ubuntu successfully.

Steps to reproduce the behavior

Described above.

Expected behavior

1. The installer should do a sanity check on the value provided and not proceed if the set size is smaller than the minimum size the partition can have.
2. The installer could be re-runnable and not get stuck at the last error.

Ubuntu release

24.04 LTS

What architecture are you using?

amd64

System info

6.11.0-8-generic #8-Ubuntu SMP PREEMPT_DYNAMIC Mon Sep 16 13:41:20 UTC 2024
name: ubuntu-desktop-bootstrap
summary: Ubuntu Desktop Bootstrap
publisher: Canonical✓
store-url: https://snapcraft.io/ubuntu-desktop-bootstrap
license: GPL-3.0
description: |
This project is a modern implementation of the Ubuntu Desktop installer,
using subiquity as a backend and Flutter for the UI.
snap-id: dLfoSWlQziHta7kJaco3IhnPwGVJ3bIt
channels:
latest/stable: 0+git.66bf8d183 2024-07-24 (237) 122MB classic
latest/candidate: 0+git.2f88d9b70 2024-08-19 (242) 122MB classic
latest/beta: ↑
latest/edge: ↑
25.04/stable: 0+git.ded09ee4d 2024-12-19 (299) 110MB classic
25.04/candidate: ↑
25.04/beta: ↑
25.04/edge: 0+git.ded09ee4d 2024-12-10 (299) 110MB classic
24.10/stable: 0+git.8f7b50565 2024-10-08 (290) 111MB classic
24.10/candidate: ↑
24.10/beta: ↑
24.10/edge: 0+git.8f7b50565 2024-10-08 (290) 111MB classic
24.04/stable: 0+git.66bf8d183 2024-08-14 (237) 122MB classic
24.04/candidate: ↑
24.04/beta: ↑
24.04/edge: 0+git.61036cc38 2025-01-10 (301) 117MB classic

name: snapd
summary: Daemon and tooling that enable snap packages
publisher: Canonical✓
store-url: https://snapcraft.io/snapd
contact: https://github.com/snapcore/snapd/issues
license: GPL-3.0
description: |
Install, configure, refresh and remove snap packages. Snaps are
'universal' packages that work across many different Linux systems,
enabling secure distribution of the latest apps and utilities for
cloud, servers, desktops and the internet of things.

Start with 'snap list' to see installed snaps.
type: snapd
snap-id: PMrrV4ml8uWuEUDBT8dSGnKUYbevVhc4
tracking: latest/stable
refresh-date: vor 39 Tagen, um 08:43 CET
channels:
latest/stable: 2.66.1 2025-01-09 (23258) 46MB -
latest/candidate: 2.67 2024-12-17 (23545) 46MB -
latest/beta: 2.67 2024-12-04 (23545) 46MB -
latest/edge: 2.67+git126.gf9578f5 2025-01-10 (23703) 50MB -
installed: 2.66.1 (23258) 46MB snapd

Additional context

No response