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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 1131FC3276C for ; Thu, 2 Jan 2020 22:59:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E203220866 for ; Thu, 2 Jan 2020 22:59:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727557AbgABW7k (ORCPT ); Thu, 2 Jan 2020 17:59:40 -0500 Received: from authsmtp03.register.it ([81.88.48.53]:39121 "EHLO authsmtp.register.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727409AbgABWN5 (ORCPT ); Thu, 2 Jan 2020 17:13:57 -0500 X-Greylist: delayed 339 seconds by postgrey-1.27 at vger.kernel.org; Thu, 02 Jan 2020 17:13:55 EST Received: from [192.168.1.1] ([93.41.32.9]) by cmsmtp with ESMTPSA id n8b9ir9UONsF7n8b9iIhju; Thu, 02 Jan 2020 23:05:43 +0100 X-Rid: guido@trentalancia.com@93.41.32.9 Message-ID: <1578002742.5239.0.camel@trentalancia.com> Subject: [PATCH RESEND v2] scsi: ignore Synchronize Cache command failures to keep using drives not supporting it From: Guido Trentalancia To: linux-scsi@vger.kernel.org Date: Thu, 02 Jan 2020 23:05:42 +0100 X-Priority: 1 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4wfPgX4JmffzOxSPLNZSjriTpfYy85Mj9vtPFI/FL/a90X78EhvTYpbE+O5cCCA7AcF3UKvsZ/uA9nvCIhGsIhQo3ArL6KH4rYsCPAkfogEtwuK3DPk3rM EyJW3QxLATAMTpj+GPaFw6ALQE5reIQtpRGraLnuIXip0IUbQmz+jvWC75xdS5fbIz869MXtanGcSg== Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Many obsolete hard drives do not support the Synchronize Cache SCSI command. Such command is generally issued during fsync() calls which at the moment therefore fail with the ILLEGAL_REQUEST sense key. Since this failure is currently treated as critical in the kernel SCSI disk driver, such obsolete hard drives cannot be used anymore: they cannot be formatted, mounted and/or checked using tools such as e2fsprogs. Because there is nothing which can be done if the drive does not support such command, such ILLEGAL_REQUEST should be treated as non-critical so that the underlying operation does not fail and the obsolete hard drive can be used normally. This patch disables the Write Cache feature as a precaution on hard drives which do not support the Synchronize Cache command and therefore the cache flushing functionality. Fixes bug: https://bugzilla.kernel.org/show_bug.cgi?id=203635 Signed-off-by: Guido Trentalancia --- drivers/scsi/sd.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff -pru a/drivers/scsi/sd.c b/drivers/scsi/sd.c --- a/drivers/scsi/sd.c 2019-03-17 18:22:04.822720851 +0100 +++ b/drivers/scsi/sd.c 2019-03-20 17:41:44.526957307 +0100 @@ -22,6 +22,10 @@ * - Badari Pulavarty , Matthew Wilcox * , Kurt Garloff : * Support 32k/1M disks. + * - Guido Trentalancia ignore Synchronize + * Cache command failures on hard-drives that do not support it + * and disable the Write Cache functionality on such devices as a + * precaution: this allows to keep using several obsolete drives. * * Logging policy (needs CONFIG_SCSI_LOGGING defined): * - setting up transfer: SCSI_LOG_HLQUEUE levels 1 and 2 @@ -1633,6 +1637,20 @@ static int sd_sync_cache(struct scsi_dis } if (res) { + /* + * sshdr.sense_key == ILLEGAL_REQUEST means this drive + * doesn't support sync. There's not much to do and + * sync shouldn't fail. + */ + if (sshdr->sense_key == ILLEGAL_REQUEST && sshdr->asc == 0x20) { + if (sdkp->WCE) { + sdkp->WCE = 0; + sd_printk(KERN_NOTICE, sdkp, "Drive does not support Synchronize Cache(10) command: disabling write cache.\n"); + sd_set_flush_flag(sdkp); + } + return 0; + } + sd_print_result(sdkp, "Synchronize Cache(10) failed", res); if (driver_byte(res) == DRIVER_SENSE) @@ -2022,6 +2040,17 @@ static int sd_done(struct scsi_cmnd *SCp req->rq_flags |= RQF_QUIET; } break; + case SYNCHRONIZE_CACHE: + if (sshdr.asc == 0x20) { + if (sdkp->WCE) { + sdkp->WCE = 0; + sd_printk(KERN_NOTICE, sdkp, "Drive does not support Synchronize Cache(10) command: disabling write cache.\n"); + sd_set_flush_flag(sdkp); + } + SCpnt->result = 0; + good_bytes = scsi_bufflen(SCpnt); + } + break; } } break;