Ext4 file system corruption and possible data loss
ubuntu-users at list-post.mks-mail.de
Tue Jan 19 21:23:20 UTC 2010
19.01.2010 19:18, Ari Torhamo:
> Thanks Markus for your reply. The problem with this non-booting Ubuntu
> 9.10 system has turned out to be serious. I connected the hard disk it's
> installed on to my own computer to test it, and found out that both ext4
> partitions on the disk are more or less unreadable. Gnome disk utility
> says that the /home partition is "unknown or unused" and it also isn't
> visible in Nautilus. The system partition is shown as "Linux ext4
> (version 1.0)", but the content cannot be read (the lost+found folder is
> there, but I'm not able to set the permission to myself - and there's no
> user data on that partition anyway).
> I ran "fsck.ext4 -pfv" for both partitions (I'm not familiar with this
> tool, so I may have done something wrong), and I got the following
I wouldn't have run fsck on the file-systems on the disk but created
images of the file-systems via dd first and operated on those.
> System partition:
> ari at mung-papu:~$ sudo fsck.ext4 -pfv /dev/sdb6
> 11 inodes used (0.00%)
> 0 non-contiguous files (0.0%)
> 0 non-contiguous directories (0.0%)
> # of inodes with ind/dind/tind blocks: 0/0/0
> Extent depth histogram: 1
> 99190 blocks used (2.71%)
> 0 bad blocks
> 1 large file
> 0 regular files
> 2 directories
> 0 character device files
> 0 block device files
> 0 fifos
> 0 links
> 0 symbolic links (0 fast symbolic links)
> 0 sockets
> 2 files
Whatever trashed the disk, it seems it did a good job...
> When I tried to re-install Ubuntu to the problematic system partition,
> the following error message was shown right after the installation
> "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
> 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.
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
Oh, before you do anything else, backup the Windows partition.
> 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:
> It's been more than a month since the user did the last back-up, so some
> data will be lost, if there's no success. Of course it would be
> important to know what lead to this situation too, as the reliability of
> the operating system (using the word in the broad meaning) might be in
Indeed, that would be important to know.
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.
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.
More information about the ubuntu-users