From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 6/6] nvme: ignore retries for multipath devices
Date: Tue, 3 Oct 2017 13:53:55 +0200 [thread overview]
Message-ID: <20171003115355.GB24650@lst.de> (raw)
In-Reply-To: <9d603720-2f86-ab3c-6ba3-9d57afb3568e@suse.de>
On Tue, Oct 03, 2017@12:02:38PM +0200, Hannes Reinecke wrote:
> >> if (nvme_req(req)->status & NVME_SC_DNR)
> >> return false;
> >> - if (nvme_req(req)->retries >= nvme_max_retries)
> >> + if (nvme_req(req)->retries >= nvme_max_retries &&
> >> + !(req->cmd_flags & REQ_NVME_MPATH))
> >> return false;
> >> return true;
> >
> > All failover logic is inside a nvme_req_needs_retry() conditional,
> > so this change looks completely broken - it basically disables
> > failover.
> >
> Not in our tests.
> Without this patch we'd been seeing I/O errors during failover; with
> this patch I/O continues on the failover path.
http://git.infradead.org/users/hch/block.git/blob/refs/heads/nvme-mpath:/drivers/nvme/host/core.c#l208
210 if (unlikely(nvme_req(req)->status && nvme_req_needs_retry(req))) {
211 if (nvme_req_needs_failover(req)) {
212 nvme_failover_req(req);
213 return;
214 }
The only call to nvme_failover_req is guarded by nvme_req_needs_retry,
and you change needs_retry to return true for MPATH requests that
exceed the number of retries. I just don't see how we'd hit the
max_retries count, as each retry before should have already taken
nvme_req_needs_failover before. What error code do you see this
with? What kinds of device/setup?
next prev parent reply other threads:[~2017-10-03 11:53 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-02 13:55 [PATCH 0/6] nvme: sanitize multipathing Hannes Reinecke
2017-10-02 13:55 ` [PATCH 1/6] nvme: display 'CMIC' controller attribute Hannes Reinecke
2017-10-02 16:15 ` Christoph Hellwig
2017-10-02 13:55 ` [PATCH 2/6] nvme: use 'nvmsXnZ' instead of 'nvm-subXnZ' Hannes Reinecke
2017-10-02 16:16 ` Christoph Hellwig
2017-10-02 16:20 ` Keith Busch
2017-10-11 14:32 ` Guan Junxiong
2017-10-02 13:55 ` [PATCH 3/6] nvme: claim block devices Hannes Reinecke
2017-10-02 16:42 ` Christoph Hellwig
2017-10-03 10:08 ` Hannes Reinecke
2017-10-03 11:55 ` Christoph Hellwig
2017-10-04 5:42 ` Hannes Reinecke
2017-10-04 6:15 ` Christoph Hellwig
2017-10-04 6:33 ` Hannes Reinecke
2017-10-04 7:13 ` Christoph Hellwig
2017-10-04 7:26 ` Hannes Reinecke
2017-10-05 1:08 ` Martin K. Petersen
2017-10-05 6:51 ` Johannes Thumshirn
2017-10-05 14:05 ` Keith Busch
2017-10-05 14:39 ` Hannes Reinecke
2017-10-05 14:47 ` Christoph Hellwig
2017-10-02 13:55 ` [PATCH 4/6] nvme: display 'NMIC' namespace attribute Hannes Reinecke
2017-10-02 16:16 ` Christoph Hellwig
2017-10-03 10:00 ` Hannes Reinecke
2017-10-03 11:49 ` Christoph Hellwig
2017-10-03 16:01 ` Hannes Reinecke
2017-10-02 13:55 ` [PATCH 5/6] nvme: Export subsystems to /sys/class/nvme-subsys Hannes Reinecke
2017-10-02 16:18 ` Christoph Hellwig
2017-10-02 16:53 ` Keith Busch
2017-10-02 16:56 ` Christoph Hellwig
2017-10-02 17:15 ` Keith Busch
2017-10-02 13:55 ` [PATCH 6/6] nvme: ignore retries for multipath devices Hannes Reinecke
2017-10-02 16:22 ` Christoph Hellwig
2017-10-03 10:02 ` Hannes Reinecke
2017-10-03 11:53 ` Christoph Hellwig [this message]
2017-10-02 14:35 ` [PATCH] nvme: reset retires after path failover Johannes Thumshirn
2017-10-02 14:43 ` Keith Busch
2017-10-02 15:08 ` Hannes Reinecke
2017-10-02 14:45 ` Johannes Thumshirn
2017-10-02 16:25 ` Christoph Hellwig
2017-10-02 14:46 ` Johannes Thumshirn
2017-10-02 16:19 ` Christoph Hellwig
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