From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB1A5C433E9 for ; Thu, 28 Jan 2021 13:42:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 602FC64DD6 for ; Thu, 28 Jan 2021 13:42:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232108AbhA1NmI (ORCPT ); Thu, 28 Jan 2021 08:42:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:41629 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231948AbhA1NmG (ORCPT ); Thu, 28 Jan 2021 08:42:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611841239; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xeXt/3GD1lqhnzmzfzzeknEhxPUiBt6dMOrPZLESt+0=; b=gk2BexUwdYDE6RDY6oQYEHi+gdyOzZ5YjpF7NY/09DS5J3k6ZL2X+8Vvburnft3leL5lTy kXlpohX22a8QRXZCVR4LaiKilo5l7SY+TavBlKjInwuybZYlvxnyqnwG5BFQJTg4PP82Q/ 3UEMTtqn31VkqoXFkBALA8EzzVqZSyQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-29--goOE2lmOu-0ptGBjxMhbA-1; Thu, 28 Jan 2021 08:40:35 -0500 X-MC-Unique: -goOE2lmOu-0ptGBjxMhbA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 10A2A9CC01; Thu, 28 Jan 2021 13:40:34 +0000 (UTC) Received: from ovpn-113-224.phx2.redhat.com (ovpn-113-224.phx2.redhat.com [10.3.113.224]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3CF3160C13; Thu, 28 Jan 2021 13:40:33 +0000 (UTC) Message-ID: <0650909876af42f1b7e8f2ec16445e4cb4f8d4d4.camel@redhat.com> Subject: Re: [PATCH] scsi: do not retry FAILFAST commands on DID_TRANSPORT_DISRUPTED From: "Ewan D. Milne" To: Hannes Reinecke , michael.christie@oracle.com, "Martin K. Petersen" Cc: Christoph Hellwig , James Bottomley , linux-scsi@vger.kernel.org, Martin Wilck , Hannes Reinecke Date: Thu, 28 Jan 2021 08:40:32 -0500 In-Reply-To: References: <20210126130212.47998-1-hare@suse.de> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Thu, 2021-01-28 at 07:57 +0100, Hannes Reinecke wrote: > On 1/28/21 1:51 AM, michael.christie@oracle.com wrote: > > On 1/26/21 7:02 AM, Hannes Reinecke wrote: > > > When a command is return with DID_TRANSPORT_DISRUPTED we should > > > be looking at the REQ_FAILFAST_TRANSPORT flag and do not retry > > > the command if set. > > > Otherwise multipath will be requeuing a command on the failed > > > path and not fail it over to one of the working paths. > > > > > > Cc: Martin Wilck > > > Signed-off-by: Hannes Reinecke > > > --- > > > drivers/scsi/scsi_error.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/scsi/scsi_error.c > > > b/drivers/scsi/scsi_error.c > > > index a52665eaf288..005118385b70 100644 > > > --- a/drivers/scsi/scsi_error.c > > > +++ b/drivers/scsi/scsi_error.c > > > @@ -1753,6 +1753,7 @@ int scsi_noretry_cmd(struct scsi_cmnd > > > *scmd) > > > case DID_TIME_OUT: > > > goto check_type; > > > case DID_BUS_BUSY: > > > + case DID_TRANSPORT_DISRUPTED: > > > return (scmd->request->cmd_flags & > > > REQ_FAILFAST_TRANSPORT); > > > case DID_PARITY: > > > return (scmd->request->cmd_flags & REQ_FAILFAST_DEV); > > > > We don't fast fail for that error code to avoid churn for > > transient > > transport problems. The FC and iscsi drivers block the > > rport/session, > > return that code and then it's up the fast_io_fail/replacement > > timeout. > > > > _But_ if prevents that command to be failed over to another path, so > essentially we're blocking execution until fast_io_fail tmo. > > For no good reason as we have other paths available. And if we don't? Not everybody sets queue_if_no_path, right? -Ewan > > Cheers, > > Hannes