Re: UBI fastmap updates

[Artem Bityutskiy]

Richard,

On Thu, 2012-08-02 at 18:32 +0200, Richard Weinberger wrote:
> > This should not happen. Fastmap should _reserve_ enough of PEBs for it
> > to operate. It should always find the PEB to write.
> 
> What is the benefit?
> IOW what is wrong with the current approach?

Several reasons. The main is: fastmap will start consuming PEBs reserved
for volumes when the amount of available PEBs is just enough to map all
LEBs. This will break UBI liability.

> Why?
> If everything goes wrong, fastmap makes sure that no fastmap is on
> flash.
> In case of a powercut we fall back to scanning mode.
> R/O mode is overkill IMHO.

So can I interpret this the following way. Not only fastmap give no
guarantees that it exists after an unclean reboot, it does not even give
guarantees that it exists after a clean reboot.

Unless I am confused, the fastmap design is over-simplified.


-- 
Best Regards,
Artem Bityutskiy

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