Ext4 file system corruption and possible data loss

[Ari Torhamo]

ti, 2010-01-19 kello 22:23 +0100, Markus Schönhaber kirjoitti:
> 19.01.2010 19:18, Ari Torhamo:

> > When I tried to re-install Ubuntu to the problematic system partition,
> > the following error message was shown right after the installation
> > started:
> > 
> > "Failed to remove conflicting files
> > The installer needs to remove operating system files from the install
> > target, but was unable to do so. The install cannot continue."
> >
> > I also tried to remove and recreate the system partition before
> > installing, but got the same error message anyway. 
> 
> Which is to be expected. Deleting and re-creating the partition didn't
> change it's content.
> Make sure that the installer formats the partition, i. e. creates a new
> file-system from scratch (or do that manually before you start the
> installation).

Re-installing with the formating option was actually the first thing I
tried - that's how I typically do a new installation.

> > I run a thorough test for the hard disk, and no errors were found.
> > Complete run of Memtest showed no errors either (in the computer that
> > the hard disk belongs to). The Windows installation on the disk works
> > without problems.
> 
> Nevertheless, I'd check the drive's SMART status before I'd trust it
> with any data. Palimpsest can show SMART data - if you like a GUI.

I used the test tool that Western Digital provides to test the drive.
This tool does the same tests as SMART does plus the surface scan.
Palimpsest also says the disk is running well "SMART wise".

> Moreover, the problem might be caused by a corrupted partition table.
> You could use something like testdisk to see if it finds the start of
> file-systems at places where they shouldn't be according to the
> partition table.

I have no idea how to do this, but I'll try to search for a tool.

> Oh, before you do anything else, backup the Windows partition.

Yes, good idea.

> > What might be the next step to try to get the /home partition readable?
> 
> Well, I'm out of ideas. But you might want to browse through this thread
> of the linux-ext4 mailing list:
> http://markmail.org/message/3w5tbyaiho7os4fr

Thanks, the topic seems to go a little over my head, but I'll try to get
it.

> Although something may have gone wrong during the installation of the
> updates, I doubt that it's Ubuntu's fault. If there really was a bug in
> the update process, it almost certainly would have hit more than just
> one machine - and we would have heard the outcry.

Yes, I thought that too. Perhaps there was something wrong with the
installation disk, that only showed up as a problem now. I did check the
disk for errors though, before installing.

> And since the canonical answer to the question "What did you do when
> that happened?" of a user who has just fubar'ed his system is
> "Absolutely nothing!!!", I don't see much chance to get much information
> from the user.

The user is my brother, and he'll tell me all he everything he knows. He
is not a hacker by any means, and he uses Ubuntu just for the web,
email, text editing and normal file viewing. He's very careful with the
computer (always shuts down properly, has over voltage protection
installed and reports everything unusual to me), especially nowadays, as
he has had a lot of computer problems in the past - both hardware and
software realted -, and he want's strictly avoid anything that could
shake the system in any way. If he gets an error message he doesn't
recognize, he calls me or brings it up later. 

He's computer is only four and half months old and he boght it to get
rid of the problems that plagued his previous system even after some
components were changed (there were both hardware and software realated
problems - and perhaps compatibility too -, and some times I just
couldn't tell). No need to tell he is rather disillusioned about
computers and operating systems now. He changed to Ubuntu a few years
ago, because I recommended it as a more reliable, secure and carefree
(and ethical) alternative to Windows. Now they both are beginning to
look more or less the same to him (excluding ethically) :-/

Thanks for your help

-Ari-