Re: [PATCH] mtd: nand: Use the mirror BBT descriptor when reading its version

[Robert Jarzmik <robert.jarzmik@free.fr>]

Artem Bityutskiy <dedekind1@gmail.com> writes:

> On Mon, 2012-06-18 at 19:59 +0200, Robert Jarzmik wrote:
>> To store worn out blocks, each filesystem implementation has to do something
>> smart. UBI has it way, SAFTL (docg3 fs) has its way, etc ...
>
> UBI does not do anything about storing the bad block table. UBI relies
> on the MTD layer - it may mark a block as bad and MTD should take care
> of storing this information either in the OOB or in the BBT on in both
> places.
Urg ... I was under the impression UBI stored that information in its control
data, too bad for me ...

>> But in the end, the bad block table is immutable, and represents factory bad
>> blocks, not up-to-date list of bad blocks.
> How do you store the information about the later developed bad blocks?

Well, I think ... I don't actually. I should review a bit docg3 driver, as there
is a spare byte in the OOB area to store information. The trick is, if the block
is already worn out, can I rely on OOB to store the bad block info ?

I remember seeing people on this mailing list discussing this topic, but I can't
remember the outcome ...

>> As to whether you should kill it or not, it's up to the maintainer of diskonchip
>> I suppose.
> There is no DoC maintainer, you can consider yourself to be the
> maintainer, because you and Mike are the only people who care about this
> AFAICS.
Same as Mike, I don't have the hardware. If somebody has some spare hardware to
provide, I'd gladly take over the maintenership.

Cheers.

-- 
Robert