Re: [PATCH 03/24] nvme: let set_capacity_revalidate_and_notify update the bdev size

[Christoph Hellwig <hch@lst.de>]

On Mon, Nov 09, 2020 at 08:53:58AM +0100, Hannes Reinecke wrote:
>> index 376096bfc54a83..4e86c9aafd88a7 100644
>> --- a/drivers/nvme/host/core.c
>> +++ b/drivers/nvme/host/core.c
>> @@ -2053,7 +2053,7 @@ static void nvme_update_disk_info(struct gendisk *disk,
>>   			capacity = 0;
>>   	}
>>   -	set_capacity_revalidate_and_notify(disk, capacity, false);
>> +	set_capacity_revalidate_and_notify(disk, capacity, true);
>>     	nvme_config_discard(disk, ns);
>>   	nvme_config_write_zeroes(disk, ns);
>> @@ -2136,7 +2136,6 @@ static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_id_ns *id)
>>   		blk_stack_limits(&ns->head->disk->queue->limits,
>>   				 &ns->queue->limits, 0);
>>   		blk_queue_update_readahead(ns->head->disk->queue);
>> -		nvme_update_bdev_size(ns->head->disk);
>>   		blk_mq_unfreeze_queue(ns->head->disk->queue);
>>   	}
>>   #endif
>
> Hold on.
> This, at the very least, should be a separate patch.
> With this you are changing the behaviour of nvme multipath.
>
> Originally nvme multipath would update/change the size of the multipath 
> device according to the underlying path devices.
> With this patch the size of the multipath device will _not_ change if there 
> is a change on the underlying devices.

Yes, it will.  Take a close look at nvme_update_disk_info and how it is
called.