On Mon, Nov 02, 2015 at 03:43:07AM +0100, Rafael J. Wysocki wrote:

I guess it may also helps to address the case when a device is removed from a
suspended system, written to on another system in the meantime and inserted
back into the (still suspended) original system which then is resumed.  Today
this is an almost guaranteed data corruption scenario, but if the filesystem in
question is properly frozen during suspend, the driver should be able to detect
superblock changes during unfreeze.

Never going to work. There is no guarantee that a write to a
filesystem by a third party device is going to change the superblock
(or any metadata in the rest of the filesystem) in any detectable
way.  Hence freezing filesystems will not prevent Bad Things
Happening if you do this while your system is suspended.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com