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From: "Bryn M. Reeves" <bmr@redhat.com>
To: Hannes Reinecke <hare@suse.de>
Cc: Steffen Maier <maier@linux.vnet.ibm.com>,
	linux-scsi@vger.kernel.org, Chad Dupuis <chad.dupuis@qlogic.com>,
	Andrew Vasquez <andrew.vasquez@qlogic.com>,
	James Smart <james.smart@emulex.com>,
	James Bottomley <jbottomley@parallels.com>,
	Mike Christie <michaelc@cs.wisc.edu>
Subject: Re: [PATCH] scsi_transport_fc: Make 'port_state' writeable
Date: Fri, 15 Mar 2013 12:01:29 +0000	[thread overview]
Message-ID: <51430D99.4010604@redhat.com> (raw)
In-Reply-To: <51430C4A.7090308@suse.de>

On 03/15/2013 11:55 AM, Hannes Reinecke wrote:
> Rationale for this patch is a weird test case with brocade switches;
> there you can actually disable a _target_ port. So the port isn't
> reachable anymore but no RSCN is send.

I think it's more than a pure test-case; using the rscnsupr feature on 
the Brocades is just a handy way to trigger it.

I've seen numerous cases in the last few years of fabric failures that 
had this characteristic - either because of hardware failures in the 
switches or due to bugs that caused FC traffic to be blackholed without 
an RSCN or other indication (beyond commands timing out).

This (and the I_T nexus reset you proposed in December which is very 
effective at short-ciruiting the eh escalation in the same situation) 
both make the kernel more robust in the face of this kind of problem.

Regards,
Bryn.



  reply	other threads:[~2013-03-15 12:04 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-15 15:02 [PATCH] scsi_transport_fc: Make 'port_state' writeable Hannes Reinecke
2013-03-14 18:09 ` Steffen Maier
2013-03-15 11:55   ` Hannes Reinecke
2013-03-15 12:01     ` Bryn M. Reeves [this message]
2013-03-15 12:24     ` Bart Van Assche
2013-03-15 12:37       ` Bryn M. Reeves
2013-03-15 12:46         ` Bart Van Assche
2013-03-15 13:28           ` Bryn M. Reeves
2013-03-15 13:41             ` Bart Van Assche
2013-03-15 18:51               ` Mike Christie
2013-03-15 19:13                 ` Bart Van Assche
2013-03-15 21:12                   ` Mike Christie
2013-03-18  7:09                   ` Hannes Reinecke
2013-04-01 21:06                     ` James Smart
2013-04-04  6:26                       ` Hannes Reinecke
2013-04-05 15:14                         ` James Smart
2013-04-12 14:24                           ` Chad Dupuis
2013-03-18 21:54             ` Jeremy Linton
2013-04-01 20:51     ` James Smart

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