[PATCHv2] nvmet: lift blocksize restriction to 64k

[Christoph Hellwig]

On Fri, Feb 20, 2026 at 05:42:25PM +0100, Hannes Reinecke wrote:
> On 2/20/26 16:32, Christoph Hellwig wrote:
>> On Fri, Feb 20, 2026 at 04:12:59PM +0100, Hannes Reinecke wrote:
>>> With commit 47dd67532303 ("block/bdev: lift block size restrictions to 64k")
>>> we can now support up to 64k block sizes, so lift the restriction on 4k for
>>> file-backed namespaces.
>>
>> Still not sure this is a great idea by default.  Yes, modern Linux supports
>> 64k sector sizes, but even then just for a few file systems.  And this
>> changes existing setups, which will now break when upgrading the kernel.
>>
> How so? There cannot be any existing nvmet setup with an LBS backing 
> device, as the device will be rejected when trying to setup the target.
> Which breakage do you see here?

There can be a setup with a large i_blkbits that we limit to 4k
export LBA size right now, and with your patch it will be exposed
as something larger.