[Dev] [RFC] Tizen system rollback

Aliaksei Katovich a.katovich at samsung.com
Mon Dec 2 11:35:21 GMT 2013


hi Łukasz;

> It was <2013-11-29 pią 16:07>, when Aliaksei Katovich wrote:
> > hi all;
> >
> > 	I would like to bring to your attention Tizen system rollback feature.
> > 	The idea is to provide possibility to roll back Tizen based system to
> > 	one of several known working configurations. Most obvious use-cases are:
> >
> > 	* system update or upgrade failed;
> > 	* there are regressions introduced by system update;
> > 	* User does not like features added by system update;
> > 	* User wants to restore device to first time configuration;
> > 	* User wants to restore device to factory defaults.
> >
> > 	Proposed architecture is based on device-mapper thin-provisioning
> > 	capabilities. Please find more details in attached document.
> >
> > 	Before starting actual implementation of this feature I would like to
> > 	hear your opinion about presented architecture and the idea in general.
> 
> I am not sure if btrfs' "file-system specific" (p. 6) is a falw. Tight

	Maybe it is not, but what to do with single-device-many-filesystems
	setup?

	I am trying to be as generic as possible with rollbacks that's why
	block device level was so attractive to start with. Especially if
	we think of Tizen as of being not just mobile platform.

> integration of snapshots with file-system code *may* (it is yet to be
> measured) bring better performance. It would also allow for snapshots
> for /boot (p. 11).

	How? Teach bootloader to deal with snapshots?

> I am not very fond of the "first boot" thingie. I think as much as
> possible should be done in the factory when the image is built. The only
> thing that the "first boot" should (as far as I can tell now) do is to
> grow file-systems to fill partitions. Actually growing (and anything
> else necessary) should be done/tried upon every boot and there should be
> short code paths to check if it is needed.

	Agree on all your points. But how it is related to creating factory
	restore snapshot? This is just one, non-exclusive step amongst the
	others.

--
Aliaksei

> 
> -- 
> Łukasz Stelmach
> Samsung R&D Institute Poland
> Samsung Electronics




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