Re: [PATCH 2/2] nvme: re-read ANA log page after ns scan completes

[Keith Busch <kbusch@kernel.org>]

On Thu, Apr 03, 2025 at 05:32:59PM +0200, Hannes Reinecke wrote:
> On 4/3/25 16:55, Keith Busch wrote:
> > On Thu, Apr 03, 2025 at 09:19:30AM +0200, Hannes Reinecke wrote:
> > > When scanning for new namespaces we might have missed an ANA AEN,
> > > so we should always re-read the ANA log page after scanning to ensure
> > > we don't miss updates there.
> > 
> > Worst case we might check a log page that hasn't changed. Rescans should
> > be rare, so I guess it's fine. But I'm not sure why scanning might cause
> > an ANA AEN to be missed. ?
> Well, it's not that we're _missing_ AENs here.
> As per quoted spec ANA change events are not sent if there had been
> an event (on the controller) which would have caused both an ANA change
> event and an NS changed AEN to be sent.
> 
> So any NS changed event really needs to be treated as a combination of
> NS changed _and_ ANA changed, and after each namespace rescan we need
> to re-read the ANA log page.

Oh, good call. I forgot about that text.