From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [dm-devel] [PATCH 1/1] multipath-tools: Change path checker for IBM IPR devices Date: Thu, 25 Sep 2014 09:57:43 -0700 Message-ID: <20140925165743.GA20621@infradead.org> References: <20140924195721.148637349@linux.vnet.ibm.com> <20140924195752.289011902@linux.vnet.ibm.com> <5423B664.2020007@suse.de> <5424472E.4060300@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:50786 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751937AbaIYQ5p (ORCPT ); Thu, 25 Sep 2014 12:57:45 -0400 Content-Disposition: inline In-Reply-To: <5424472E.4060300@linux.vnet.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Brian King Cc: device-mapper development , linux-scsi@vger.kernel.org, James Bottomley On Thu, Sep 25, 2014 at 11:47:42AM -0500, Brian King wrote: > The issue we've run into started when this patch started making its > way into distros: > > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/scsi/scsi_error.c?id=14216561e164671ce147458653b1fea06a4ada1e > > That changed the behaviour for user initiated TUR commands. After an ipr > adapter gets reset, all disk array devices require a start unit command > to be issued to them before they will accept commands. So, with the SCSI > EH change, we now end up in a scenario with dual ipr adapters where the > TUR getting issued from the health checker returns with a Not Ready response > and since SCSI EH no longer triggers the Start Unit in this scenario, > the path never recovers. > > The alternative solution would be to change the TUR path checker in multipath-tools > to issue a Start Unit if it sees a 02/04/02. Or we could fix up the check introduced by the commit, with something ala: diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index a2c3d3d..7228d9e 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -459,13 +459,18 @@ static int scsi_check_sense(struct scsi_cmnd *scmd) if (! scsi_command_normalize_sense(scmd, &sshdr)) return FAILED; /* no valid sense data */ - if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done) + if (scmd->cmnd[0] == TEST_UNIT_READY && + scmd->request->cmd_type == REQ_TYPE_FS && + scmd->scsi_done != scsi_eh_done) { /* * nasty: for mid-layer issued TURs, we need to return the * actual sense data without any recovery attempt. For eh - * issued ones, we need to try to recover and interpret + * issued ones, we need to try to recover and interpret, + * and for pass through TURs we just need to stay out of the + * way, so that the device handlers can do the right thing. */ return SUCCESS; + } scsi_report_sense(sdev, &sshdr); > > Thanks, > > Brian > > -- > Brian King > Power Linux I/O > IBM Linux Technology Center > > > -- > dm-devel mailing list > dm-devel@redhat.com > https://www.redhat.com/mailman/listinfo/dm-devel ---end quoted text---