Re: complete boot failure in 4.5-rc1 caused by nvme: make SG_IO support optional

[Hannes Reinecke]

On 02/08/2016 04:12 PM, Keith Busch wrote:
> On Mon, Feb 08, 2016 at 11:13:50AM +0100, Christoph Hellwig wrote:
>> On Mon, Feb 08, 2016 at 12:01:16PM +0200, Sagi Grimberg wrote:
>>>
>>>> Do we have defined sysfs attributes for NVMe devices nowadays?
>>>
>>> /sys/block/nvme0n1/uuid
>>
>> That's only supported for NVMe 1.1 and higher devices, and optional.
>> For older or stupid devices we need to support the algorithm based
>> on the serial attribute from nvme_fill_device_id_scsi_string() in
>> drivers/nvme/host/scsi.c.
> 
> It's even worse. NGUID was defined for 1.2 devices and higher. 1.1
> devices should have EUI-64 at:
>  
>   /sys/block/nvmeXnY/eui
> 
> 1.2 devices will have either uuid or eui (or both).
> 
> The majority of devices in circulation today are 1.0, and need to concat
> these three entries to make a unique identifier:
> 
>   /sys/block/nvmeXnY/device/serial
>   /sys/block/nvmeXnY/device/model
>   /sys/block/nvmeXnY/nsid

Ok, so what about having a 'wwid' attribute which provides combined
information (like scsi has)?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
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