[dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct

[Christoph Hellwig]

On Mon, Nov 30, 2020 at 10:44:21AM +0100, Jan Kara wrote:
> I know I'm like a broken record about this but I still don't understand
> here... I'd expect the new code to be:
> 
> 	if (size == capacity ||
> 	    (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
> 		return false;
> 	pr_info("%s: detected capacity change from %lld to %lld\n",
> 		disk->disk_name, size, capacity);
> +	if (!capacity || !size)
> +		return false;
> 	kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
> 	return true;
> 
> At least that would be equivalent to the original functionality of
> set_capacity_and_notify(). And if you indeed intend to change when
> "RESIZE=1" events are sent, then I'd expect an explanation in the changelog
> why this cannot break userspace (I remember we've already broken some udev
> rules in the past by generating unexpected events and we had to revert
> those changes in the partition code so I'm more careful now). The rest of
> the patch looks good to me.

I explained that I think the GENHD_FL_UP is the more useful one here in
reply to your last comment.   If the size changes to or from 0 during
runtime we probably do want an event.

But I'll add your hunk for now and we can discuss this separately.