Re: [PATCH] nvme: retrigger ANA log update if group descriptor isn't found

From: "George, Martin" <Martin.George@netapp.com>
To: "hch@lst.de" <hch@lst.de>,
	"kbusch@kernel.org" <kbusch@kernel.org>,
	"sagi@grimberg.me" <sagi@grimberg.me>, hare <hare@suse.de>
Cc: "Meneghini, John" <John.Meneghini@netapp.com>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	"Knight, Frederick" <Frederick.Knight@netapp.com>
Subject: Re: [PATCH] nvme: retrigger ANA log update if group descriptor isn't found
Date: Thu, 25 Mar 2021 10:55:51 +0000	[thread overview]
Message-ID: <92763a7271a1eb07e28901e3e91345568202eda3.camel@netapp.com> (raw)
In-Reply-To: <cbfc78e1-87be-cc09-9b8d-44bf0659eb26@grimberg.me>

On Wed, 2021-01-13 at 19:13 -0800, Sagi Grimberg wrote:
> 
> > If ANA is enabled but no ANA group descriptor is found when
> > creating
> > a new namespace the ANA log is most likely out of date, so trigger
> > a re-read. The namespace will be tagged with the NS_ANA_PENDING
> > flag
> > to exclude it from path selection until the ANA log has been re-
> > read.
> > 
> > Reported-by: Martin George <marting@netapp.com>
> > Signed-off-by: Hannes Reinecke <hare@suse.de>
> > ---
> >   drivers/nvme/host/multipath.c | 4 ++++
> >   1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/nvme/host/multipath.c
> > b/drivers/nvme/host/multipath.c
> > index 74896be40c17..ee4a42dc99a0 100644
> > --- a/drivers/nvme/host/multipath.c
> > +++ b/drivers/nvme/host/multipath.c
> > @@ -667,6 +667,10 @@ void nvme_mpath_add_disk(struct nvme_ns *ns,
> > struct nvme_id_ns *id)
> >               if (desc.state) {
> >                       /* found the group desc: update */
> >                       nvme_update_ns_ana_state(&desc, ns);
> > +             } else {
> > +                     /* group desc not found: trigger a re-read */
> > +                     set_bit(NVME_NS_ANA_PENDING, &ns->flags);
> > +                     queue_work(nvme_wq, &ns->ctrl->ana_work);
> 
> btw, I just commented on the original thread, but I do like this
> one better.
> 
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
> 

We now have a ratified ECN which clarifies that a NVME_AEN_CFG_NS_ATTR
is sufficient for announcing a new namespace along with a new ANA
group, as opposed to additionally raising a NVME_AEN_CFG_ANA_CHANGE as
well for the latter - available at 
https://nvmexpress.org/wp-content/uploads/NVM-Express-1.4-Ratified-ECN.zip
. I hope that finally clears the confusion on this topic.

So could we now have this patch pulled in please?

-Martin
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