[PATCH 2/3] nvme-multipath: cannot disconnect controller on stuck partition scan

[Hannes Reinecke]

On 10/7/24 20:19, Keith Busch wrote:
> On Mon, Oct 07, 2024 at 12:01:33PM +0200, Hannes Reinecke wrote:
>> @@ -239,6 +239,13 @@ static bool nvme_path_is_disabled(struct nvme_ns *ns)
>>   {
>>   	enum nvme_ctrl_state state = nvme_ctrl_state(ns->ctrl);
>>   
>> +	/*
>> +	 * Skip deleted controllers for I/O from partition scan
>> +	 */
>> +	if (state == NVME_CTRL_DELETING &&
>> +	    mutex_is_locked(&ns->ctrl->scan_lock))
>> +		return true;
> 
> This feels off to me, using these seemingly unrelated dependencies to
> make these kinds of decisions.
> 
> We talked a couple weeks ago about suppressing the parition scanning
> during nvme scan_work. I know you said there was some reason it wouldn't
> work, but could you check the below? It seems okay to me.
> 
> ---
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 48e7a8906d012..82cb1eb3a773b 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -586,6 +586,12 @@ static void nvme_requeue_work(struct work_struct *work)
>   		container_of(work, struct nvme_ns_head, requeue_work);
>   	struct bio *bio, *next;
>   
> +	if (test_and_clear_bit(GD_SUPPRESS_PART_SCAN, &head->disk->state)) {
> +		mutex_lock(&head->disk->open_mutex);
> +		bdev_disk_changed(head->disk, false);
> +		mutex_unlock(&head->disk->open_mutex);
> +	}
> +
>   	spin_lock_irq(&head->requeue_lock);
>   	next = bio_list_get(&head->requeue_list);
>   	spin_unlock_irq(&head->requeue_lock);
> @@ -629,6 +635,7 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
>   		return PTR_ERR(head->disk);
>   	head->disk->fops = &nvme_ns_head_ops;
>   	head->disk->private_data = head;
> +	set_bit(GD_SUPPRESS_PART_SCAN, &head->disk->state);
>   	sprintf(head->disk->disk_name, "nvme%dn%d",
>   			ctrl->subsys->instance, head->instance);
>   	return 0;
> --
Hmm. Sadly, not really. Still stuck in partition scanning.
Guess we'll need to check if we have paths available before triggering 
partition scan; let me check ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
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