[PATCH] nvme-core: update NS Attr Changed AEN handling for ANA group

[Keith Busch]

On Wed, Dec 09, 2020 at 05:02:05PM +0100, Hannes Reinecke wrote:
> On 12/9/20 4:53 PM, Keith Busch wrote:
> > On Wed, Dec 09, 2020 at 03:20:57PM +0000, Knight, Frederick wrote:
> > > When a namespace is created (and contained in an ANA Group), the act
> > > of creating that namespace results in a change to the ANA Log page -
> > > therefore AEN.
> > 
> > That is wrong: creating a namespace doesn't do anything to the ANA log.
> > Only attached namespaces appear in the log. Creating a namespace
> > doesn't result in automatically attaching it to any controller.
> > 
> > You are thinking of Namespace Attach from section 5.19, and the spec
> > doesn't define any special exceptions for events resulting from *that*
> > command, which is also the command that triggered this thread.
> > 
> Actually, no, we're not thinking about 'Namespace Attach'.

This patch is the result from an Attach command, otherwise the host
driver wouldn't have found an unknown ANA group for a new namespace
during the rescan.

> This is a normal namespace creation on the controller side.
>
> I do agree that 'Namespace Attach' would have different constrains and rules
> under which AENs will be sent, but this is not what our initial use-case was
> about.

The use case in this patch is about getting the host to recognize the
ANA group of a newly attached namespace. If you stop at namespace
creation, then this patch doesn't do anything.