Re: Apparent serious progressive ext4 data corruption bug in 3.6.3 (and other stable branches?)

On 24 Oct 2012, Theodore Ts'o told this:

hurt, but we do want to make 100% sure that it really fixes the
problem.

Well, yes, that would be nice. I can certainly try to verify that it
stops my filesystems getting corrupted. (And if so, I owe you a
$BEVERAGE. Though I suspect I owe you about three million of those
already for other code written in the past.)

quoted

The bug did really quite a lot of damage to my /home fs in only a few
minutes of uptime, given how few files I wrote to it. What it could have
done to a more conventional distro install with everything including
/home on one filesystem, I shudder to think.

Well, the problem won't show up if the journal has wrapped.  So it
will only show up if the system has been rebooted twice in fairly
quick succession.  A full conventional distro install probably
wouldn't have triggered a bug...

A full *install* from scratch, no. I was more worried about the
possibility of someone running -stable kernels on an existing distro
installation, and shutting down every night (given what's been happening
to UK electricity prices in the last few years I suspect there are quite
a lot of people doing that in the UK to save power). If they happen not
to do much on one particular day other than a bit of light distro
updating, they could perfectly well end up roasting things touched
during the distro update. Things like glibc :(

                                 although someone who habitually
reboots their laptop instead of using suspend/resume or hiberbate, or
someone who is trying to bisect the kernel looking for some other bug
could easily trip over this --- which I guess is how you got hit by
it.

I was first hit by it in /var before I was even trying to bisect: I was
just rebooting to unwedge NFS lockd. It's true that in less than a week
probably not all that many people have rebooted often enough to trip
over this.

I hope.

-- 
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