[PATCH] nvme: unregister when pr_register() is given a zero new key

[Keith Busch]

On Thu, Oct 29, 2026 at 09:51:24AM +0900, Daejun Park via B4 Relay wrote:
> From: Daejun Park <daejun7.park at samsung.com>
> 
> The block layer PR API defines a zero new_key in pr_register() as
> unregistering old_key. nvme_pr_register() sends Replace Reservation
> Key with a zero NRKEY instead. The host stays registered with key 0,
> and its next registration with another key fails with Reservation
> Conflict.
> 
> The pNFS SCSI layout client unregisters this way at umount. A later
> mount cannot register and sends all I/O through the metadata server.
> 
> Send Unregister Reservation Key when new_key is zero.

Thanks, applied to nvme-7.4.