[RFC v7] UBI: Fastmap support (aka checkpointing)

[Shmulik Ladkani]

Hi Artem,

On Sat, 26 May 2012 15:41:34 +0300 Artem Bityutskiy <dedekind1 at gmail.com> wrote:
> On Wed, 2012-05-23 at 13:06 +0200, Richard Weinberger wrote:
> > v1: https://lwn.net/Articles/481612/
> > v2: https://lwn.net/Articles/496586/
> > v3: Didn't release it to linux-mtd
> > v4: http://article.gmane.org/gmane.linux.kernel/1297626
> > v5: http://article.gmane.org/gmane.linux.kernel/1298488
> > v6: https://lwn.net/Articles/498041/
> 
> Hi Richard,
> 
> while my daughters are sleeping, I have a chance to quickly review the
> code. I just start from the attaching path and add TODOs.
> 
> Can we change our workflow a bit. I will create a branch for fastmap in
> the UBI tree taking v7 as the base. I'll add my TODOs there and commit,
> and send them also as a patch to the mailing list. You then send
> incremental patches which fix TODOs or anything else.
> 
> We can discuss my notes and if some of them make no sens - the patch
> would just kill the TODO.
> 
> In any case, I feel a need to switch to incremental development and get
> incremental patches instead of code drops. You can send entire fastmap
> work to the list from time to time, of course, for people to look.
> 
> How does this sound?
> 
> Also, I'd like you to document the tests you do. I'd like to start
> making sure that we never break anything.
> 
> We can start with the UBI tests from the mtd-utils plust the integck
> test. And whatever goes to my branch should never break them. Do these
> tests pass now? If not, let's make them pass.
> 
> How does this sound to you?
> 
> At some later points we'll start to move pieces to the master branch.
> 
> Shmulik, is it fine with you?

Fine with me, I'm flexible ;)

What's your plan for merging to the master branch?

BTW, I know you formerly disliked the idea, but I'm in favor of having a
CONFIG for the fastmap feature; with the config disabled, UBI must
behave exactly as it was. The config can be later removed.

Update regarding status of my review:
I've reviewed fastmap's wiring up into UBI, as of v6.
I still need to review fastmap.c itself and ubi-media.h.
I focused on general correctness and addressing issues that might affect
existing UBI behavior, and less on the design itself - you can probably
shed more light in this area.

Regards,
Shmulik