Re: [PATCH] raid0: data corruption when using trim

[Gionatan Danti <g.danti@assyoma.it>]

Hi Seunguk,
thank you for your further explanation.

Does it means that only driver with Queued TRIM are affected, or it 
affect all TRIM-capable driver?

What I wounder is that, if it is only a timing-triggered problem, why it 
is only apparent on specific SSDs? I would expect it to manifest on 
other devices also, albeit with different frequency.

Sorry if some questions sound dumb, I'm only trying to understand.
Thanks.


On 24/07/15 14:19, Seunguk Shin wrote:
> Gionatan,
>
> Because it is related with timing.
>
> 1st trim is issued and before complete it, 2nd trim is started
> (allocates memory but is not issued to device)
> Then, when 1st trim is completed, it frees 2nd trim's memory,
> because they share the pointer due to bug.
> If 3rd trim is started before 2nd trim is issued to device,
> 3rd trim can allocate the same memory with 2nd trim,
> because it is freed when 1st trim is completed.
> Only this case makes the corruption.
>
> Thank you,
> Seunguk Shin
>
>>
>> Hi, any idea on why the bug affects/manifests only on specific SATA SSDs?
>> It is timing related, or it depends on how the controller manage TRIM
>> requests?
>>
>> Thanks.
>>
>> --
>> Danti Gionatan
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-- 
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@assyoma.it - info@assyoma.it
GPG public key ID: FF5F32A8