Re: [PATCH 2/2] nvme: fix atomic write boundary validation

[Christoph Hellwig <hch@lst.de>]

On Mon, Jun 16, 2025 at 11:19:44AM +0100, John Garry wrote:
> On 11/06/2025 06:54, Christoph Hellwig wrote:
>>   		ret = nvme_init_effects(ctrl, id);
>>   		if (ret)
>>   			goto out_free;
>> +
>> +		ctrl->subsys->awupf = le16_to_cpu(id->awupf);
>>   	}
>> +
>> +	if (le16_to_cpu(id->awupf) != ctrl->subsys->awupf) {
>> +		dev_err_ratelimited(ctrl->device,
>> +			"inconsistent AWUPF, controller not added (%u/%u).\n",
>> +			le16_to_cpu(id->awupf), ctrl->subsys->awupf);
>
> Could we just disable atomic writes instead of doing this?
>
> Or are there bigger issues, like the value returned from 
> nvme_update_disk_info() for setting the physical block size is just not 
> valid?

This brings up back to the old problem of how do we tell the file system
and/or application that the atomic write size it probed suddenly went
away entirely because a new controller disappeared.