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Date: Mon, 16 Jun 2008 09:42:49 +0300
From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
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To: Zhao Forrest <forrest.zhao@gmail.com>
Subject: Re: A question about UBIFS
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Hi,

Zhao Forrest wrote:
> Hi Artem,
> I have a basic question about NAND flash page update in UBIFS/UBI,
> take the following as an example:
> 1 a NAND flash with page size of 4KB, erase block size of 256KB, so
> there're 64 pages within an erase block
> 2 page 0 - page 10 has invalid data content, page 11 - page 63 has
> valid data content from FS's point of view
> 3 UBIFS attempts to update(or rewrite) page 11
> My question is how page 11 is updated by UBIFS/UBI?
> I only read the design docs of UBI and guess that for this particular
> case a new physical eraseblock is got by UBI, then new content of page
> 11 is written to page 11 of new physical eraseblock, page 12 - page 63
> in original physical eraseblock are copied to new physical eraseblock,
> lastly the mapping between logical eraseblock and physical eraseblock
> is updated. Am I right?

Right. All updates are out-of-place.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)