From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Hannes Reinecke <hare@suse.de>
Cc: emilne@redhat.com, Christoph Hellwig <hch@lst.de>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
James Bottomley <james.bottomley@hansenpartnership.com>,
linux-scsi@vger.kernel.org, Hannes Reinecke <hare@suse.com>
Subject: Re: [PATCH] sd: always scan VPD pages if thin provisioning is enabled
Date: Wed, 25 Jan 2017 21:45:17 -0500 [thread overview]
Message-ID: <yq1ziiea69u.fsf@oracle.com> (raw)
In-Reply-To: <02181dcf-0177-d2f3-545e-264d87bc489b@suse.de> (Hannes Reinecke's message of "Wed, 25 Jan 2017 15:38:35 +0100")
>>>>> "Hannes" == Hannes Reinecke <hare@suse.de> writes:
Hannes,
Hannes> Thing is, setting 'WS16' here is arguably wrong, as LPBME just
Hannes> means 'logical block provisioning management enabled', not
Hannes> 'WRITE SAME 16 with UNMAP' supported.
Things are the way they are because many devices predate the final SBC
spec. They report LBPME=1 but do not have the VPD page indicating their
preferred deprovisioning command. The VPD was added very late in the
spec and there are a ton of devices that don't have it. As a result, we
default to WS16 unless the device reports the UNMAP parameters in the
Block Limits VPD.
That has been a very solid heuristic for a long time so please don't
mess with that.
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2017-01-26 2:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-25 7:26 [PATCH] sd: always scan VPD pages if thin provisioning is enabled Hannes Reinecke
2017-01-25 7:57 ` Johannes Thumshirn
2017-01-25 10:23 ` Christoph Hellwig
2017-01-25 10:38 ` Hannes Reinecke
2017-01-25 14:27 ` Ewan D. Milne
2017-01-25 14:38 ` Hannes Reinecke
2017-01-25 15:38 ` James Bottomley
2017-01-25 16:47 ` Hannes Reinecke
2017-01-26 2:45 ` Martin K. Petersen [this message]
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