Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756697AbdCHC7x (ORCPT ); Tue, 7 Mar 2017 21:59:53 -0500 Received: from userp1050.oracle.com ([156.151.31.82]:25419 "EHLO userp1050.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756548AbdCHC7i (ORCPT ); Tue, 7 Mar 2017 21:59:38 -0500 To: Stephen Hemminger Cc: kys@microsoft.com, haiyangz@microsoft.com, longli@microsoft.com, martin.petersen@oracle.com, hch@lst.de, hare@suse.de, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, Stephen Hemminger Subject: Re: [PATCH] storvsc: workaround for virtual DVD SCSI version From: "Martin K. Petersen" Organization: Oracle Corporation References: <20170307171553.13247-1-sthemmin@microsoft.com> Date: Tue, 07 Mar 2017 20:21:44 -0500 In-Reply-To: <20170307171553.13247-1-sthemmin@microsoft.com> (Stephen Hemminger's message of "Tue, 7 Mar 2017 09:15:53 -0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Source-IP: userp1040.oracle.com [156.151.31.81] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1078 Lines: 25 >>>>> "Stephen" == Stephen Hemminger writes: Stephen, Stephen> Hyper-V host emulation of SCSI for virtual DVD device reports Stephen> SCSI version 0 (UNKNOWN) but is still capable of supporting Stephen> REPORTLUN. Stephen> Without this patch, a GEN2 Linux guest on Hyper-V will not boot Stephen> 4.11 successfully with virtual DVD ROM device. What happens is Stephen> that the SCSI scan process falls back to doing sequential Stephen> probing by INQUIRY. But the storvsc driver has a previous Stephen> workaround that masks/blocks all errors reports from INQUIRY Stephen> (or MODE_SENSE) commands. This workaround causes the scan to Stephen> then populate a full set of bogus LUN's on the target and then Stephen> sends kernel spinning off into a death spiral doing block reads Stephen> on the non-existent LUNs. Stephen> By setting the correct blacklist flags, the target with the DVD Stephen> device is scanned with REPORTLUN and that works correctly. Applied to 4.11/scsi-fixes. Thank you! -- Martin K. Petersen Oracle Linux Engineering