From: Christoph Hellwig <hch@infradead.org>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
"Anner, Ran" <Ran.Anner@dell.com>,
Sagi Grimberg <sagi@grimberg.me>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"Engel, Amit" <Amit.Engel@dell.com>
Subject: Re: nvme reservation commands during controller reset
Date: Sat, 15 Aug 2020 08:00:16 +0100 [thread overview]
Message-ID: <20200815070016.GA20460@infradead.org> (raw)
In-Reply-To: <20200814160220.GC3772144@dhcp-10-100-145-180.wdl.wdc.com>
On Fri, Aug 14, 2020 at 09:02:20AM -0700, Keith Busch wrote:
> Couldn't you just clear the REQ_DRIVER_FAILFAST flag to get the existing
> retry mechanisms working in this path?
That would only retry locally and thus not really help.
>
> And while it looks fine for fabrics, PCIe doesn't have the implied HOST
> ID connection that makes reservations do the right thing across
> different paths. Automatic path failover retries for PCIe may have the
> wrong result.
You need a host id for reservations to work properly, as without that
they won't actually be persistent. Unfortunasly NVMe allows
reservations without a hostid with some rather broken semantics instead
of just failing them, so applications that do use reservations needs
to ensure a host id is set.
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next prev parent reply other threads:[~2020-08-15 7:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-05 7:14 nvme reservation commands during controller reset Engel, Amit
2020-08-09 16:10 ` Keith Busch
2020-08-10 12:40 ` Christoph Hellwig
2020-08-10 15:13 ` Engel, Amit
2020-08-10 15:48 ` Keith Busch
2020-08-11 20:48 ` Sagi Grimberg
2020-08-12 7:00 ` Engel, Amit
2020-08-14 8:20 ` Christoph Hellwig
2020-08-14 10:09 ` Christoph Hellwig
2020-08-14 16:02 ` Keith Busch
2020-08-15 7:00 ` Christoph Hellwig [this message]
2020-08-14 18:29 ` Sagi Grimberg
2020-08-15 7:01 ` Christoph Hellwig
2020-08-17 7:56 ` Sagi Grimberg
2020-08-17 8:12 ` Christoph Hellwig
2020-08-17 19:29 ` Sagi Grimberg
2020-08-18 6:36 ` Christoph Hellwig
2020-08-18 17:18 ` Sagi Grimberg
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