From: Jonathan Lundell <jlundell@pobox.com>
To: Chris Wedgwood <cw@f00f.org>
Cc: Daniel Phillips <phillips@bonn-fries.net>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Andrew Morton <andrewm@uow.edu.au>,
Andreas Dilger <adilger@turbolinux.com>,
"Albert D. Cahalan" <acahalan@cs.uml.edu>,
Ben LaHaise <bcrl@redhat.com>,
Ragnar Kjxrstad <kernel@ragnark.vestdata.no>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
mike@bigstorage.com, kevin@bigstorage.com, linux-lvm@sistina.com
Subject: Re: [PATCH] 64 bit scsi read/write
Date: Sun, 15 Jul 2001 10:44:28 -0700 [thread overview]
Message-ID: <p0510031cb7778611bd3f@[207.213.214.37]> (raw)
In-Reply-To: <20010716032220.B10635@weta.f00f.org>
In-Reply-To: <E15LL3Y-0000yJ-00@the-village.bc.nu> <0107142211300W.00409@starship> <20010715153607.A7624@weta.f00f.org> <01071515442400.05609@starship> <20010716023911.A10576@weta.f00f.org> <p05100317b7775fc2bd15@[207.213.214.37]> <20010716032220.B10635@weta.f00f.org>
At 3:22 AM +1200 2001-07-16, Chris Wedgwood wrote:
>On Sun, Jul 15, 2001 at 08:06:39AM -0700, Jonathan Lundell wrote:
>
> At first glance, by the way, the only write barrier I see in the
> SCSI command set is the synchronize-cache command, which completes
> only after all the drive's dirty buffers are written out. Of
> course, without write caching, it's not an issue.
>
>Is the spec you have distributable? I believe some of the early drafts
>were, but the final spec isn't.
>
>I'd really like to check it out myself, I alwasy assumed SCSI had the
>smarts for write-barriers and force-unit-access but I guess I was
>wrong.
>
>Anyhow, I'd like to see the spec for myself if it is something I can
>get hold of.
I was referring to IBM's spec, as implemented in their recent SCSI
and FC drives. You can find a copy at
http://www.storage.ibm.com/techsup/hddtech/prodspec/ddyf_spi.pdf
WRITE EXTENDED has a bit (FUA) that will let you force that
particular write to go to disk immediately, independent of write
caching, but there's no suggestion that it otherwise acts as a write
barrier for cached writes.
WRITE VERIFY implies a CACHE SYNCHRONIZE, so it's a write barrier,
but an expensive (because synchronous) one.
--
/Jonathan Lundell.
next prev parent reply other threads:[~2001-07-15 17:45 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-01 4:53 [RFC][PATCH] first cut 64 bit block support Ben LaHaise
2001-07-03 4:53 ` Ragnar Kjørstad
2001-07-04 2:19 ` [PATCH] 64 bit scsi read/write Ben LaHaise
2001-07-04 7:11 ` Alan Cox
2001-07-05 6:34 ` Ragnar Kjørstad
2001-07-05 7:35 ` Ben LaHaise
2001-07-13 18:20 ` Albert D. Cahalan
2001-07-13 20:41 ` Andreas Dilger
2001-07-13 21:07 ` Chris Wedgwood
2001-07-13 22:04 ` Andreas Dilger
2001-07-14 0:49 ` Jonathan Lundell
2001-07-14 12:27 ` Paul Jakma
2001-07-14 14:48 ` Chris Wedgwood
2001-07-14 15:42 ` Paul Jakma
2001-07-14 17:18 ` Chris Wedgwood
2001-07-20 17:03 ` Stephen C. Tweedie
2001-07-16 18:53 ` Andreas Dilger
2001-07-16 19:13 ` Ragnar Kjørstad
2001-07-13 21:14 ` Alan Cox
2001-07-14 3:23 ` Andrew Morton
2001-07-14 8:45 ` Alan Cox
2001-07-14 14:50 ` Chris Wedgwood
2001-07-14 20:11 ` Daniel Phillips
2001-07-15 1:21 ` Andrew Morton
2001-07-15 1:53 ` Daniel Phillips
2001-07-15 3:36 ` Chris Wedgwood
2001-07-15 6:05 ` John Alvord
2001-07-15 6:07 ` Chris Wedgwood
2001-07-15 13:16 ` Ken Hirsch
2001-07-15 14:50 ` Chris Wedgwood
2001-07-15 22:14 ` Daniel Phillips
2001-07-17 0:31 ` Juan Quintela
2001-07-15 13:44 ` Daniel Phillips
2001-07-15 14:39 ` Chris Wedgwood
2001-07-15 15:32 ` Alan Cox
2001-07-15 15:33 ` Chris Wedgwood
2001-07-15 16:24 ` Chris Wedgwood
2001-07-15 15:06 ` Jonathan Lundell
2001-07-15 15:22 ` Chris Wedgwood
2001-07-15 17:44 ` Jonathan Lundell [this message]
2001-07-15 17:47 ` Justin T. Gibbs
2001-07-15 23:14 ` Rod Van Meter
2001-07-16 0:37 ` Jonathan Lundell
2001-07-16 15:11 ` Rod Van Meter
2001-07-16 8:56 ` Chris Wedgwood
2001-07-16 13:19 ` Daniel Phillips
2001-07-16 1:08 ` Albert D. Cahalan
2001-07-16 8:49 ` Chris Wedgwood
2001-07-21 19:18 ` Alexander Griesser
2001-07-22 3:52 ` Albert D. Cahalan
2001-07-23 14:41 ` Daniel Phillips
2001-07-24 4:29 ` Albert D. Cahalan
2001-07-24 11:45 ` Daniel Phillips
2001-07-14 15:41 ` Jonathan Lundell
2001-07-14 17:00 ` Chris Wedgwood
2001-07-14 17:33 ` Jonathan Lundell
2001-07-15 4:02 ` Chris Wedgwood
2001-07-15 5:46 ` Jonathan Lundell
2001-07-15 17:10 ` Chris Wedgwood
2001-07-15 17:39 ` Jonathan Lundell
2001-07-26 2:18 ` Ragnar Kjørstad
2001-07-26 16:24 ` Andreas Dilger
2001-08-10 19:42 ` Ben LaHaise
2001-08-10 19:51 ` Ragnar Kjørstad
2001-08-10 20:02 ` Ben LaHaise
2001-08-11 0:18 ` Steve Lord
2001-08-11 21:44 ` Matti Aarnio
2001-07-04 10:16 ` [RFC][PATCH] first cut 64 bit block support Chris Wedgwood
2001-07-04 16:59 ` Ben LaHaise
2001-07-14 15:08 [PATCH] 64 bit scsi read/write Ed Tomlinson
2001-07-19 7:35 [PATCH] 64 bit SCSI read/write Andre Hedrick
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