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From: Hannes Reinecke <hare@suse.de>
To: John Utz <John.Utz@wdc.com>, Christoph Hellwig <hch@infradead.org>
Cc: "linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	James Bottomely <jbottomley@parallels.com>
Subject: Re: [PATCH 4/4] sd: Handle ZBC drives correctly
Date: Mon, 21 Jul 2014 19:49:17 +0200	[thread overview]
Message-ID: <53CD529D.4050504@suse.de> (raw)
In-Reply-To: <8A51900D08212F40B3DE22453052F69839C47278@wdscexmb02>

On 07/21/2014 06:18 PM, John Utz wrote:
> If I read Hanne's patch correctly, he is checking for the ZBC signature
 > when the drives are probed.
>
Yep.

> Thus, the only circumstance where adding zbc handling would lead to
 > unexpected bad behavior in sd would be if a ZBC drive reported itself
 > as a standard ATA drive or an ATA drive reported itself as a ZBC drive.

It's actually worse than that:
Currently libata will happily attach to a ZAC device, and passing them 
on to the SCSI stack as a normal disk device.
Which most definitely will lead to unexpected results :-)

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)

  parent reply	other threads:[~2014-07-21 17:49 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-21  8:27 [PATCHv2 0/4] Initial SMR drive support Hannes Reinecke
2014-07-21  8:27 ` [PATCH 1/4] libata: consolidate ata_dev_classify() Hannes Reinecke
2014-07-21  8:27 ` [PATCH 2/4] libata: Implement ATA_DEV_ZAC Hannes Reinecke
2014-07-21  8:27 ` [PATCH 3/4] libata-scsi: Update SATL for ZAC drives Hannes Reinecke
2014-07-21  8:27 ` [PATCH 4/4] sd: Handle ZBC drives correctly Hannes Reinecke
2014-07-21 11:29   ` Christoph Hellwig
2014-07-21 11:51     ` Hannes Reinecke
2014-07-21 15:01       ` Christoph Hellwig
2014-07-21 16:18       ` John Utz
2014-07-21 16:30         ` John Utz
2014-07-21 17:49         ` Hannes Reinecke [this message]
2014-07-22 16:19         ` Christoph Hellwig
2014-07-22 18:25           ` John Utz

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