Follow-up of https://bugzilla.redhat.com/show_bug.cgi?id=2353002.

Currently the backend requires bootloader partition to be present for home reuse autopart (https://github.com/rhinstaller/anaconda/blob/84cd12d77fca4472b2d43797b7cb6b4ba26fc980/pyanaconda/modules/storage/partitioning/automatic/automatic_partitioning.py#L154 ).

This is not the case for installations with MBR-partitioned disks (using msdos partition table / disklabel).

We had to disable the feature in the frontend for F42 release:  https://github.com/rhinstaller/anaconda-webui/pull/742

Goal:

Support home reuse feature on MBR-partitioned disks.

Acceptance Criteria:

It is possible to use webui "Reinstall Fedora" feature on existing installations with MBR-partitioned disks. Installations like F42 (rawhide) netinst with this kickstart:

# Default Fedora Rawhide repositories
# url --url http://dl.fedoraproject.org/pub/fedora/linux/development/rawhide/Everything/x86_64/os/
network --bootproto=dhcp
bootloader --timeout=1
zerombr
clearpart --all --initlabel --disklabel msdos
autopart
keyboard us
lang en
timezone America/New_York
rootpw qweqwe
user --name=user1 --password="user1_password" --groups=wheel
shutdown
%packages
%end

Testing note:

GPT partitioning was made default in Fedora 37. To create a system for testing it should be possible to:

• use Fedora 36 with btrfs autopartitioning
• use current Fedora (F41, rawhide) with autopart and msdos disklabel set
  • by inst.disklabel=mbr boot option
  •  clearpart --initlabel --disklabel msdos kickstart command
• There is an existing webui that creates such an existing layout with move_standard_fedora_disk_to_MBR_disk function

It would be nice to have this covered by kickstart tests but we don't expose the backend functionality intentionally, see: https://github.com/pykickstart/pykickstart/pull/499.