Messages in this thread | | | Date | Thu, 19 Dec 2013 11:22:16 +1100 | From | Dave Chinner <> | Subject | Re: [RFC][PATCH] PM / Sleep: Freeze filesystems during system suspend/hibernation |
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On Wed, Dec 18, 2013 at 03:08:42PM +0100, Pavel Machek wrote: > > > > 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.
Freezing the filesystem prevents that accidental mount of the filesystem from being an issue. It fixes a bug that:
> Documentation/power/swsusp.txt: > > * BIG FAT WARNING > ********************************************************* > * > * If you touch anything on disk between suspend and resume... > * ...kiss your data goodbye.
Makes this a whole lot less dangerous.
> > > 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?
Please read more carefully: "affect every journalled filesystem linux supports". So, ext3 is affected because it's a journalling filesystem. I didn't list every journalled filesystem Linux supports - "etc" means there are more examples that aren't explicitly listed.
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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