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 for linux-mtd@lists.infradead.org; Tue, 15 Mar 2016 15:33:04 +0000
Subject: Re: Page migration issue with UBIFS
To: "Kirill A. Shutemov" <kirill@shutemov.name>
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From: Richard Weinberger <richard@nod.at>
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Date: Tue, 15 Mar 2016 16:32:40 +0100
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Am 15.03.2016 um 16:17 schrieb Kirill A. Shutemov:
> On Tue, Mar 15, 2016 at 03:16:11PM +0100, Richard Weinberger wrote:
>> Hi!
>>
>> We're facing this issue from 2014 on UBIFS:
>> http://www.spinics.net/lists/linux-fsdevel/msg79941.html
>>
>> So sum up:
>> UBIFS does not allow pages directly marked as dirty. It want's everyone to do it via UBIFS's
>> ->wirte_end() and ->page_mkwirte() functions.
>> This assumption *seems* to be violated by CMA which migrates pages.
> 
> I don't thing the CMA/migration is the root cause.
> 
> How did we end up with writable and dirty pte, but not having
> ->page_mkwrite() called for the page?
> 
> Or if ->page_mkwrite() was called, why the page is not dirty?

BTW: UBIFS does not implement ->migratepage(), could this be a problem?

Thanks,
//richard