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From: Mike Snitzer <snitzer@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
	dm-devel@redhat.com, linux-block@vger.kernel.org,
	linux-nvme@lists.infradead.org
Subject: Re: [PATCH v4 3/3] nvme: decouple basic ANA log page re-read support from native multipathing
Date: Tue, 20 Apr 2021 10:17:34 -0400
Message-ID: <20210420141734.GA14523@redhat.com> (raw)
In-Reply-To: <20210420093453.GB28625@lst.de>

On Tue, Apr 20 2021 at  5:34am -0400,
Christoph Hellwig <hch@lst.de> wrote:

> On Fri, Apr 16, 2021 at 07:53:29PM -0400, Mike Snitzer wrote:
> > Whether or not ANA is present is a choice of the target implementation;
> > the host (and whether it supports multipathing) has _zero_ influence on
> > this. If the target declares a path as 'inaccessible' the path _is_
> > inaccessible to the host. As such, ANA support should be functional
> > even if native multipathing is not.

As you well know, ANA is decoupled from multipathing in the NVMe spec.
This fix illustrates that the existing Linux NVMe ANA handling is too
tightly coupled with native NVMe multipathing. Unfortunately, you've
forced this as a means to impose your political position:

> NAK.  nvme-multipathing is the only supported option for subsystems with
> multiple controllers.

And while this is largely irrelevant to the technical review of my fix:
native nvme-multipath may be the only supported option in your world. In
mine that isn't true and never has been.

Your political posturing doesn't replace technical justification. You
don't have a compelling technical case to take the stance you do, yet
you guard it like you do. Just a really stark inconsistency in your
technical leadership that is repeatedly left unchecked by others.

Alas.


  reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-16 23:53 [PATCH v3 0/4] nvme: improve error handling and ana_state to work well with dm-multipath Mike Snitzer
2021-04-16 23:53 ` [PATCH v4 1/3] nvme: return BLK_STS_DO_NOT_RETRY if the DNR bit is set Mike Snitzer
2021-04-20  9:34   ` Christoph Hellwig
2021-04-16 23:53 ` [PATCH v4 2/3] nvme: allow local retry and proper failover for REQ_FAILFAST_TRANSPORT Mike Snitzer
2021-04-16 23:53 ` [PATCH v4 3/3] nvme: decouple basic ANA log page re-read support from native multipathing Mike Snitzer
2021-04-20  9:34   ` Christoph Hellwig
2021-04-20 14:17     ` Mike Snitzer [this message]
2021-04-17  0:02 ` [PATCH v4 0/4] nvme: improve error handling and ana_state to work well with dm-multipath Mike Snitzer
2021-04-19 14:56   ` Mike Snitzer
2021-04-20  9:37 ` [PATCH v3 " Christoph Hellwig
2021-04-20 14:38   ` Mike Snitzer
2021-04-20 15:46     ` Laurence Oberman
2021-05-01 11:58       ` Hannes Reinecke
2021-05-01 15:19         ` Mike Snitzer

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