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Date: Sun, 28 Sep 2014 13:46:22 +0300
From: Tanya Brokhman <tlinder@codeaurora.org>
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To: Richard Weinberger <richard@nod.at>, dedeking1@gmail.com
Subject: Re: [RFC/PATCH 1/5] mtd: ubi: Read disturb infrastructure
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On 9/28/2014 11:54 AM, Richard Weinberger wrote:
> Am 28.09.2014 10:48, schrieb Tanya Brokhman:
>>>> @@ -424,6 +440,8 @@ struct ubi_fm_sb {
>>>>        __be32 used_blocks;
>>>>        __be32 block_loc[UBI_FM_MAX_BLOCKS];
>>>>        __be32 block_ec[UBI_FM_MAX_BLOCKS];
>>>> +    __be32 block_rc[UBI_FM_MAX_BLOCKS];
>>>> +    __be64 block_let[UBI_FM_MAX_BLOCKS];
>>>
>>> Doesn't this break the fastmap on-disk layout?
>>
>> What do you mean "break"? I verified fastmap feature is working. the whole read-disturb depends on it so I tested this thoroughly.
>
> Did you write a fastmap with your changes applied and then an attach using a fastmap implementation *without*
> you changes?
> I bet it will not work because the disk layout is now different.

you're right, it wont work. I did a set of attach/detach tests to verify 
fastmap, but of course with my changes.

> Linux is not the only user of fastmap. We need to be very careful here.

Could you please elaborate here? I'm not sure I understand the use case 
you're referring to.

>
> Thanks,
> //richard
>
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