Re: [PATCH 0/2] nvmet: add namespace-level debugfs for reservation state

[Guixin Liu <kanie@linux.alibaba.com>]

在 2026/6/25 17:10, Guixin Liu 写道:
>
>
> 在 2026/6/25 15:17, Daniel Wagner 写道:
>> On Mon, Jun 22, 2026 at 06:44:16PM +0800, Guixin Liu wrote:
>>> This series adds debugfs support for inspecting NVMe target reservation
>>> (PR) state at the namespace level.
>>>
>>> Patch 1 introduces per-namespace debugfs directories under each 
>>> subsystem,
>>> providing the infrastructure for namespace-specific debug entries.
>>>
>>> Patch 2 adds a 'reservation' file that exposes the persistent 
>>> reservation
>>> state including enable status, generation counter, holder 
>>> information, and
>>> the full registrant list.
>>>
>>> Example output with two registered hosts and an active holder:
>>>
>>>    $ cat /sys/kernel/debug/nvmet/testnqn/ns1/reservation
>>>    enable : 1
>>>    generation : 2
>>>    notify_mask : 0x0
>>>    rtype : write_exclusive
>>>    holder : hostid=11111111-1111-1111-1111-111111111111, rkey=0x1111
>>>    registrants:
>>>      hostid=11111111-1111-1111-1111-111111111111, rkey=0x1111
>>>      hostid=22222222-2222-2222-2222-222222222222, rkey=0x2222
>> I expect blktests will make use of this interface eventually. The parser
>> for this wont be dead simple, sure doable but not simple. If you see a
>> way to make a bit simpler I wouldn't mind.
> How about this:
>
> 1. One holer, multi registrants:
>   enable=1
>   generation=2
>   notify_mask=0x0
>   rtype=write_exclusive
>   holder=11111111-1111-1111-1111-111111111111,0x1111
>   reg=11111111-1111-1111-1111-111111111111,0x1111
>   reg=22222222-2222-2222-2222-222222222222,0x2222
>
> 2. No holder, multi registrants:
>   enable=1
>   generation=1
>   notify_mask=0x0
>   rtype=none
>   holder=none
>   reg=11111111-1111-1111-1111-111111111111,0x1111
>   reg=22222222-2222-2222-2222-222222222222,0x2222
>
> 3. No registrant:
>   enable=1
>   generation=0
>   notify_mask=0x0
>   rtype=none
>   holder=none
>
> 4. Reservation not enabled:
>   enable=0
>
> Otherwise, the notify_mask can be stringization:
>
>   notify_mask=reg_preempted,resv_released,resv_preempted
>
> Best Regards,
> Guixin Liu
>
Hi Daniel,
     What do you think?

Best Regards,
Guixin Liu