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

[Daniel Wagner]

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.