From patchwork Tue Apr 11 02:28:51 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauricio Faria de Oliveira X-Patchwork-Id: 9674487 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 88DAF600CB for ; Tue, 11 Apr 2017 02:29:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 52C8C283BA for ; Tue, 11 Apr 2017 02:29:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 461942849A; Tue, 11 Apr 2017 02:29:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BA23A283BA for ; Tue, 11 Apr 2017 02:29:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752045AbdDKC3b (ORCPT ); Mon, 10 Apr 2017 22:29:31 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:35045 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751660AbdDKC3b (ORCPT ); Mon, 10 Apr 2017 22:29:31 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v3B2Su6V112041 for ; Mon, 10 Apr 2017 22:29:30 -0400 Received: from e24smtp05.br.ibm.com (e24smtp05.br.ibm.com [32.104.18.26]) by mx0a-001b2d01.pphosted.com with ESMTP id 29rh6y3c6x-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 10 Apr 2017 22:29:30 -0400 Received: from localhost by e24smtp05.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 10 Apr 2017 23:29:25 -0300 Received: from d24av02.br.ibm.com (d24av02.br.ibm.com [9.8.31.93]) by d24relay04.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v3B2TKAp34078960 for ; Mon, 10 Apr 2017 23:29:25 -0300 Received: from d24av02.br.ibm.com (localhost [127.0.0.1]) by d24av02.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v3B2T4Qg016608 for ; Mon, 10 Apr 2017 23:29:05 -0300 Received: from t440.ibm.com ([9.85.135.93]) by d24av02.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id v3B2T1Tq016516; Mon, 10 Apr 2017 23:29:02 -0300 From: Mauricio Faria de Oliveira To: linux-scsi@vger.kernel.org, brking@linux.vnet.ibm.com, wenxiong@linux.vnet.ibm.com Cc: martin.petersen@oracle.com Subject: [PATCH] ipr: do not set DID_PASSTHROUGH on CHECK CONDITION Date: Mon, 10 Apr 2017 23:28:51 -0300 X-Mailer: git-send-email 1.8.3.1 X-TM-AS-MML: disable x-cbid: 17041102-0032-0000-0000-00000553BA47 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17041102-0033-0000-0000-000011D8C640 Message-Id: <1491877731-19287-1-git-send-email-mauricfo@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-04-11_02:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1704110020 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On a dual controller setup with multipath enabled, some MEDIUM ERRORs caused both paths to be failed, thus I/O got queued/blocked since the 'queue_if_no_path' feature is enabled by default on IPR controllers. This example disabled 'queue_if_no_path' so the I/O failure is seen at the sg_dd program. Notice that after the sg_dd test-case, both paths are in 'failed' state, and both path/priority groups are in 'enabled' state (not 'active') -- which would block I/O with 'queue_if_no_path'. # sg_dd if=/dev/dm-2 bs=4096 count=1 dio=1 verbose=4 blk_sgio=0 <...> read(unix): count=4096, res=-1 sg_dd: reading, skip=0 : Input/output error <...> # dmesg [...] sd 2:2:16:0: [sds] FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [...] sd 2:2:16:0: [sds] Sense Key : Medium Error [current] [...] sd 2:2:16:0: [sds] Add. Sense: Unrecovered read error - recommend rewrite the data [...] sd 2:2:16:0: [sds] CDB: Read(10) 28 00 00 00 00 00 00 00 20 00 [...] blk_update_request: I/O error, dev sds, sector 0 [...] device-mapper: multipath: Failing path 65:32. <...> [...] device-mapper: multipath: Failing path 65:224. # multipath -l 1IBM_IPR-0_59C2AE0000001F80 dm-2 IBM ,IPR-0 59C2AE00 size=5.2T features='0' hwhandler='1 alua' wp=rw |-+- policy='service-time 0' prio=0 status=enabled | `- 2:2:16:0 sds 65:32 failed undef running `-+- policy='service-time 0' prio=0 status=enabled `- 1:2:7:0 sdae 65:224 failed undef running This is not the desired behavior. The dm-multipath explicitly checks for the MEDIUM ERROR case (and a few others) so not to fail the path (e.g., I/O to other sectors could potentially happen without problems). See dm-mpath.c :: do_end_io_bio() -> noretry_error() !->! fail_path(). The problem trace is: 1) ipr_scsi_done() // SENSE KEY/CHECK CONDITION detected, go to.. 2) ipr_erp_start() // ipr_is_gscsi() and masked_ioasc OK, go to.. 3) ipr_gen_sense() // masked_ioasc is IPR_IOASC_MED_DO_NOT_REALLOC, // so set DID_PASSTHROUGH. 4) scsi_decide_disposition() // check for DID_PASSTHROUGH and return // early on, faking a DID_OK.. *instead* // of reaching scsi_check_sense(). // Had it reached the latter, that would // set host_byte to DID_MEDIUM_ERROR. 5) scsi_finish_command() 6) scsi_io_completion() 7) __scsi_error_from_host_byte() // That would be converted to -ENODATA <...> 8) dm_softirq_done() 9) multipath_end_io() 10) do_end_io() 11) noretry_error() // And that is checked in dm-mpath :: noretry_error() // which would cause fail_path() not to be called. With this patch applied, the I/O is failed but the paths are not. This multipath device continues accepting more I/O requests without blocking. (and notice the different host byte/driver byte handling per SCSI layer). # dmesg [...] sd 2:2:7:0: [sdaf] Done: SUCCESS Result: hostbyte=0x13 driverbyte=DRIVER_OK [...] sd 2:2:7:0: [sdaf] CDB: Read(10) 28 00 00 00 00 00 00 00 40 00 [...] sd 2:2:7:0: [sdaf] Sense Key : Medium Error [current] [...] sd 2:2:7:0: [sdaf] Add. Sense: Unrecovered read error - recommend rewrite the data [...] blk_update_request: critical medium error, dev sdaf, sector 0 [...] blk_update_request: critical medium error, dev dm-6, sector 0 [...] sd 2:2:7:0: [sdaf] Done: SUCCESS Result: hostbyte=0x13 driverbyte=DRIVER_OK [...] sd 2:2:7:0: [sdaf] CDB: Read(10) 28 00 00 00 00 00 00 00 10 00 [...] sd 2:2:7:0: [sdaf] Sense Key : Medium Error [current] [...] sd 2:2:7:0: [sdaf] Add. Sense: Unrecovered read error - recommend rewrite the data [...] blk_update_request: critical medium error, dev sdaf, sector 0 [...] blk_update_request: critical medium error, dev dm-6, sector 0 [...] Buffer I/O error on dev dm-6, logical block 0, async page read # multipath -l 1IBM_IPR-0_59C2AE0000001F80 1IBM_IPR-0_59C2AE0000001F80 dm-6 IBM ,IPR-0 59C2AE00 size=5.2T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw |-+- policy='service-time 0' prio=0 status=active | `- 2:2:7:0 sdaf 65:240 active undef running `-+- policy='service-time 0' prio=0 status=enabled `- 1:2:7:0 sdh 8:112 active undef running Signed-off-by: Mauricio Faria de Oliveira Acked-by: Brian King --- P.S.: The switch-case checking this condition predates linux.git, so I'd like to ask Brian for a review too, as I imagine he probably might have worked with this back then (if memory may serve one this well :-) drivers/scsi/ipr.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c index b29afafc2885..1012674d9dc5 100644 --- a/drivers/scsi/ipr.c +++ b/drivers/scsi/ipr.c @@ -6293,7 +6293,12 @@ static void ipr_erp_start(struct ipr_ioa_cfg *ioa_cfg, break; case IPR_IOASC_MED_DO_NOT_REALLOC: /* prevent retries */ case IPR_IOASA_IR_DUAL_IOA_DISABLED: - scsi_cmd->result |= (DID_PASSTHROUGH << 16); + /* + * exception: do not set DID_PASSTHROUGH on CHECK CONDITION + * so SCSI mid-layer and upper layers handle it accordingly. + */ + if (ipr_cmd->scsi_cmd->result != SAM_STAT_CHECK_CONDITION) + scsi_cmd->result |= (DID_PASSTHROUGH << 16); break; case IPR_IOASC_BUS_WAS_RESET: case IPR_IOASC_BUS_WAS_RESET_BY_OTHER: