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Date: Mon, 11 Jan 2016 09:49:15 +0100
From: Peter Lieven <pl@kamp.de>
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Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] send readcapacity10 when
 readcapacity16 failed
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To: Paolo Bonzini <pbonzini@redhat.com>, John Snow <jsnow@redhat.com>, Zhu Lingshan <lszhu@suse.com>
Cc: qemu-block@nongnu.org, ronnie sahlberg <ronniesahlberg@gmail.com>, qemu-devel <qemu-devel@nongnu.org>

Am 07.01.2016 um 11:07 schrieb Paolo Bonzini:
>
> On 06/01/2016 18:57, John Snow wrote:
>> Ronnie: Thanks for the explanation!
>>
>> Zhu: In light of this, can the patch be reworked slightly to explicitly
>> check *why* READCAPACITY16 failed and only attempt the READCAPACITY10 as
>> a fallback if it receives INVALID_OPCODE?
>>
>> If it fails for any other reason it's probably best to report the error
>> and let QEMU decide what to do about it.
> Any other failure probably would happen for READ CAPACITY(10) as well, so
> it's okay to ignore it for READ CAPACITY(16).
>
> Zhu's patch matches what Linux does by default, it seems okay.  The only
> change needed is to retry READ CAPACITY(16) if there is a UNIT ATTENTION
> sense:
>
> +            if (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
> +                && task->sense.key == SCSI_SENSE_UNIT_ATTENTION) {
> +                break;
> +            }
>
> Paolo

Paolo, Ronnie, do you know what Readcapacity(10) returns if the target
blocks count is greater than what can be described in 32bit?

Anyway, is there a new version of this patch? I would also like to have a look
before it is commited.

Thanks,
Peter