Snapshotting for rollback after updates was[ Re: Drawing lessons from fatal SELinux bug #1054350]

[Tomasz Torcz]

On Sat, Jan 25, 2014 at 02:55:32PM -0500, Simo Sorce wrote:
> On Sat, 2014-01-25 at 17:46 +0100, Tomasz Torcz wrote:
> > > 
> > > If there is a directory that contains update and non-update related file
> > > changes, that's a problem. If there's segmentation, then this can be done.  
> > 
> >   Note that this situation is perfectly handled by Offline Updates.
> > After reboot, there aren't collateral changes to filesystem, only upgrade-related
> > ones. So if there's a need for revert, the previous state is clearly defined.
> 
> Sorry, but this is simply not true.
> 
> 
> The ONLY way to do that is if you do not care at all about user's data
> and simply accept that a rollback will also remove user data.
> 
> The reason is simple: lot's of software *changes* data as part of its
> normal functioning, including and often in rollback-incompatible ways.

  What user data?  There is no user data touched/created during offline upgrade.

-- 
Tomasz Torcz            There exists no separation between gods and men:
xmpp: zdzichubg at chrome.pl   one blends softly casual into the other.