Re: [PATCHv3] nvme: allow to re-attach namespaces after all paths are down

[Hannes Reinecke <hare@suse.de>]

On 5/11/21 6:26 PM, Christoph Hellwig wrote:
>>   	} else {
>>   		ret = -EINVAL;
>> +		/*
>> +		 * If multipath is enabled we might hit an ns head with no
>> +		 * paths, but that doesn't indicate it's a shared namespace.
>> +		 */
>> +		if (nvme_ns_head_multipath(head) &&
>> +		    list_empty(&head->list))
>> +			goto check_ids;
>>   		if (!is_shared || !head->shared) {
>>   			dev_err(ctrl->device,
>>   				"Duplicate unshared namespace %d\n", nsid);
>>   			goto out_put_ns_head;
>>   		}
>> +check_ids:
> 
> I think this should simply be:
> 
> 		if (!list_empty(&head->list) && (!is_shared || !head->shared)) {
>   			dev_err(ctrl->device,
>    				"Duplicate unshared namespace %d\n", nsid);
>    			goto out_put_ns_head;
>    		}
> 
I wasn't sure if this isn't just for multipathing; other setups can't 
queue I/O, so we'll be hitting this scenario only in the unlikely case 
that the device is removed _and re-attached_ without any I/O pending.
Hence the check.
But sure, I can modify it.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

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