Re: Fix SWSUSP & !SWAP

Pavel Machek
2003-04-24T14:16:40Z

Hi!

> > > > > Sorry, I still don't get it. Go through the steps for me:
> > > > >
> > > > > 1) suspend writes pages to disk
> > > > >
> > > > > 2) machine is shutdown
> > > > >
> > > > > 3) restart, journal replay
> >
> > Corruption comes here. The journal reply tidies things up that shouldn't
> > be tidied up. They shouldn't be tidied up because once we reload the
> > image, things should be in the same state as prior to suspend. If replay
> > frees a block (thinking it wasn't properly linked or something similar),
> > it introduces corruption.
>
> No, this will not happen. All swapfile blocks must be allocated by swapon
> time. It is just a chunk of disk and replay will not touch it.
>
> That's for ext3, and no other filesystems journal data anyway...

Its not about data.

Corruption is not in suspended image. Imagine you have running system
(X open, applications running, gcc compiling) and someone runs journal
replay. Bye bye data. And that's what happens there. When you restore,
restored kernel no longer knows you did replay.
Pavel
--
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]