From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>,
linux-scsi@vger.kernel.org, martin.petersen@oracle.com,
haiyangz@microsoft.com, linux-kernel@vger.kernel.org, hch@lst.de,
hare@suse.de, devel@linuxdriverproject.org
Subject: Re: [PATCH] storvsc: workaround for virtual DVD SCSI version
Date: Tue, 07 Mar 2017 20:21:44 -0500 [thread overview]
Message-ID: <yq1lgsgimvr.fsf@oracle.com> (raw)
In-Reply-To: <20170307171553.13247-1-sthemmin@microsoft.com> (Stephen Hemminger's message of "Tue, 7 Mar 2017 09:15:53 -0800")
>>>>> "Stephen" == Stephen Hemminger <stephen@networkplumber.org> 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
next prev parent reply other threads:[~2017-03-08 1:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-07 17:15 [PATCH] storvsc: workaround for virtual DVD SCSI version Stephen Hemminger
2017-03-07 17:19 ` KY Srinivasan
2017-03-07 23:31 ` Christoph Hellwig
2017-03-08 1:21 ` Martin K. Petersen [this message]
2017-03-08 7:00 ` Hannes Reinecke
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