Re: [RFC][PATCH] PM / Sleep: Freeze filesystems during systemsuspend/hibernation

From: Pavel Machek
Date: Wed Dec 18 2013 - 09:08:51 EST


> > > I disagree - given the problem it is resolving leads to silent
> > > filesystem corruption, this patch should be considered somewhat of a
> > > priority to push...
> >
> > Umm. Ok, I forgot what it does, really.
>
> It ensures that the filesystem is in an quiescent state both in
> memory and on disk, and it cannot be modified in memory or on disk
> whilst the suspend image is being generated, or by log recovery
> after a resume before the suspended image has been restored.

If someone attempts to run log recovery before resume, that's a bug
and yes, it will corrupt filesystems. (Including ext3). Don't do that.

Documentation/power/swsusp.txt:

* BIG FAT WARNING
*********************************************************
*
* If you touch anything on disk between suspend and resume...
* ...kiss your data goodbye.

> > So... for few years now suspend corrupts data on XFS? And Fedora has
> > the fix but it is not in mainline? That does not sound right...
>
> The issues freezing the filesystem before the suspend image is
> created affect every journalled filesystem linux supports, be
> it XFS, ext4, reiser, btrfs, etc.

Did not it have some problems with ext3?

Regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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