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Date: Thu, 21 Oct 2010 19:04:27 +0200
From: Matthieu CASTET <matthieu.castet@parrot.com>
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Subject: Re: ubifs: sync() causes writes even if nothing is changed
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Cc: linux-mtd <linux-mtd@lists.infradead.org>,
	Adrian Hunter <adrian.hunter@nokia.com>
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Hi,

Artem Bityutskiy a écrit :
> On Thu, 2010-10-21 at 10:23 +0200, Sebastian Andrzej Siewior wrote:
>> Artem Bityutskiy wrote:
>>>> From a quick glance at the ubifs code, this might come out of the
>>>> garbage collector that is triggered on every sync() and writes
>>>> something even if nothing has changed.
> 
> Yeah, the UBIFS must be writing the commit start and commit end nodes,
> and then erasing the previous log LEB (all this is done in log.c). As
> soon as I have time I'll look at this, I really do not have time right
> now. And there is Matthiew's problem which is actually quite big, but
> for some reasons affects only him :-)
It could be interesting to know which nand flash are tested.

On our boards ST 256MB chip work fine, but micron flash got unstable 
page problem (sorry I don't have the model number ATM).

And it is getting worse, new SLC flash can now get up to 4 bits error 
per 512.


Matthieu