Ubiquity Advanced Partitioning - Converting/Using ext4 to ext2 without formating formats the partition without warning

[komputes]

Binary package hint: ubiquity

Ubiquity Advanced Partitioning - Converting ext4 to ext2 without formatting formats the partition without warning

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: ubiquity 2.4.8
ProcVersionSignature: Ubuntu 2.6.35-22.33-generic 2.6.35.4
Uname: Linux 2.6.35-22-generic i686
NonfreeKernelModules: wl
Architecture: i386
Date: Thu Dec 2 17:02:57 2010
LiveMediaBuild: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity

[Evan (ev)]

Is the format box in the main window (not the dialog) checked when you switch filesystems?

[komputes (komputes)]

No, the format box in the "Advanced Partitioning" main window is not checked. It was simply assigned to use the partition as ext2, and use it as "/" .The installer formatted the partition anyhow, and without warning, causing loss of data.

[James Hunt (jamesodhunt)]

I'm seeing this with ubuntu_precise-desktop-i386.iso from 20th March.

[James Hunt (jamesodhunt)]

To be clear, I'm seeing the problem, but the checkbox *is* checked for me:

1) Select an ext4 partition
2) Click "Change..."
3) Set "use as" to ext2
4) Do not check the "Format the partition" checkbox
5) Specify a mount point.
6) Click OK

At this point, the "Format?" column now has a tick against the ext4 filesystem with type shown as "ext2".

The problem seems to manifest itself if you specify a partition to be mounted as a different type to how it was originally formatted. Examples:

- If you format a partition to ext4, and mount it as ext4 but select do not format, ubiquity will not reformat.
- If you format a partition to ext4, and mount it as ext2 but select do not format, ubiquity will silently reformat (as reported).
- If you format a partition to ext4, and mount it as ext3 but select do not format, ubiquity will silently reformat.
- If you format a partition to ext2, and mount it as ext3 but select do not format, ubiquity will silently reformat.

What is happening is that /lib/partman/choose_method/25filesystem/do_option is iterating through the list of valid filesystems.

Here, we have a scenario where the existing partition is ext4 and the user has selected ext2. Since the FS types do not match ($existing is 'no'), it decides that the partition needs to be formatted. Normally, this would be an entirely reasonable outcome but for the fact that:

- ext4 is backwards compatible with ext3 and ext2.
- ext3 is backwards compatible with ext2.

One solution therefore would be to add logic to /lib/partman/choose_method/25filesystem/do_option to special-case ext* filesystems and only reformat if attempting to mount say ext2 as ext4. However, clearly, ubiquity also needs to ask for user confirmation before reformatting.

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Marcus Tomlinson (marcustomlinson)]

This issue has sat incomplete for more than 60 days now. I'm going to close it as invalid. Please feel free re-open if this is still an issue for you. Thank you.