Re: UBI fastmap updates

Richard Weinberger
2012-08-02T17:06:23Z

Am Thu, 2 Aug 2012 10:03:04 -0700
schrieb Tim Bird <tim.bird@am.sony.com>:
> >> 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.
>
> Fastmap is an optimization. Maybe I'm missing something, but
> I'm not sure why, if the optimization stopped working, you
> would want to reduce the functionality of the file system.

That's *exactly* my point.
If fastmap is available - fine, we have fast boot - yay!
But if something really nasty happens we can safely fall back
to scanning mode.
And fastmap is designed to allow this.

Thanks,
//richard