From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: SCSI's heuristics for enabling WRITE SAME still need work [was:
 dm mpath: disable WRITE SAME if it fails]
Date: Tue, 24 Sep 2013 11:37:20 +0200
Message-ID: <52415D50.508@redhat.com>
References: <20130919161043.GA27081@redhat.com> <20130920212142.GA17898@redhat.com> <yq1eh8jf8wq.fsf@sermon.lab.mkp.net>
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To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com, linux-scsi@vger.kernel.org
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Il 21/09/2013 00:03, Martin K. Petersen ha scritto:
> 
> The major headache here of course is that WRITE SAME is inherently
> destructive. We can't just fire off one during discovery and see if it
> works. For WRITE you can issue a command with a transfer length of 0 to
> see if things work. But unfortunately for WRITE SAME a transfer length
> of zero means "wipe the entire device". Yikes!

What about WRITE SAME with an out-of-range lba?  Or lba equal to the
size of the disk and #blocks equal to zero.

Paolo