From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH] sd: always retry READ CAPACITY for ALUA state transition Date: Tue, 17 Oct 2017 06:57:32 -0700 Message-ID: <1508248652.3129.2.camel@HansenPartnership.com> References: <1508224276-130348-1-git-send-email-hare@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from bedivere.hansenpartnership.com ([66.63.167.143]:50544 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750853AbdJQN5e (ORCPT ); Tue, 17 Oct 2017 09:57:34 -0400 In-Reply-To: <1508224276-130348-1-git-send-email-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke , "Martin K. Petersen" Cc: Christoph Hellwig , linux-scsi@vger.kernel.org On Tue, 2017-10-17 at 09:11 +0200, Hannes Reinecke wrote: > During ALUA state transitions the device might return > a sense code 02/04/0a (Logical unit not accessible, asymmetric > access state transition). As this is a transient error > we should just retry the READ CAPACITY call until > the state transition finishes and the correct > capacity can be returned. This will lock up the system if some ALUA initiator gets into a state where it always returns transitioning and never completes, which doesn't look like the best way to handle problem devices. I thought after the ALUA transition the LUN gives a unit attention ... can't you use that some way to trigger the capacity re-read, so do asynchronous event notification instead of polling forever. James