Re: [RFC 0/9] Add persistent durable identifier to storage log messages

Tony Asleson
2020-01-02T22:52:56Z

On 12/23/19 6:50 PM, James Bottomley wrote:
> On Mon, 2019-12-23 at 16:55 -0600, Tony Asleson wrote:
>> Today users have no easy way to correlate kernel log messages for
>> storage devices across reboots, device dynamic add/remove, or when
>> the device is physically or logically moved from from system to
>> system. This is due to the existing log IDs which identify how the
>> device is attached and not a unique ID of what is
>> attached. Additionally, even when the attachment hasn't changed,
>> it's not always obvious which messages belong to the device as the
>> different areas in the storage stack use different identifiers, eg.
>> (sda, sata1.00, sd 0:0:0:0).
>>
>> This change addresses this by adding a unique ID to each log
>> message. It couples the existing structured key/value logging
>> capability and VPD 0x83 device identification.
>
> I understand why, and using the best VPD identifier we have seems fine.
> However, we're trying to dump printk in favour of dev_printk and its
> ilk, so resurrecting printk_emit instead of using dev_printk_emit looks
> a bit retrograde. It does seem that ata_dev_printk should really be
> using dev_printk ... not sure about the block case.

I'll re-work the patch series to move towards dev_printk_emit.

Thanks
-Tony