Re: Half-Disaster switching from ext3 to ext4

[Theodore Tso <tytso@mit.edu>]

On Sun, Jan 04, 2009 at 04:23:42AM +0100, Giangiacomo Mariotti wrote:
> the partitions(except for root obviously), I synced some times before
> doing that and then I shut down the pc with a "shutdown -h -P now".
> when I booted again the system, /dev/sda2(the partition with the most
> important data. Murphy's law really works!) failed to get mounted with
> a message saying something about corrupted groups(maybe, I don't
> remember exactly). Trying to do a fsck.ext4 -p /dev/sda2, I got
> something like : fsck.ext4 : Invalid argument while checking ext3
> journal for /dev/sda2. 

What version of e2fsprogs do you have installed, and can you dig up
the exact error message at mount time?  It should be in the your
system logs....

> remounted it, all files were gone! I was starting to use the sleuth
> kit, when I noticed that in the search+found directory there were
> almost all the files, but not all of them and in a rearrenged
> directory structure.

Sounds like the root inode got zapped.  As for why, it's hard to say.
It could be a simple disk failure that happend as bad luck.  I haven't
seen any other bug reports that report corruption similar to yours, so
without a lot more information or a way to reproduce the error,
there's not much more I can say.

Regards,

						- Ted