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

[Hannes Reinecke <hare@xxxxxxx>]

On 11/6/20 8:03 PM, Christoph Hellwig wrote:
> There is no good reason to call revalidate_disk_size separately.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>   drivers/nvme/host/core.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> 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.
While personally I would _love_ to have this patch, we should at least 
document this by making it a separate patch.
And we possibly should check if both sizes are the same, and think of 
what we should be doing if they are not.
Cheers,

Hannes
--
Dr. Hannes Reinecke                Kernel Storage Architect
hare@xxxxxxx                              +49 911 74053 688
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