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From: Jeff Garzik <jgarzik@pobox.com>
To: Doug Maxey <dwm@maxeymade.com>, Jens Axboe <axboe@suse.de>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
	Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>,
	linux-scsi@vger.kernel.org
Subject: Re: [PATCH] scsi/sata write barrier support
Date: Thu, 27 Jan 2005 18:00:41 -0500	[thread overview]
Message-ID: <41F97299.2070909@pobox.com> (raw)
In-Reply-To: <200501272242.j0RMgoP5016154@falcon30.maxeymade.com>

Doug Maxey wrote:
> On Thu, 27 Jan 2005 13:02:48 +0100, Jens Axboe wrote:
> 
>>Hi,
>>
>>For the longest time, only the old PATA drivers supported barrier writes
>>with journalled file systems. This patch adds support for the same type
>>of cache flushing barriers that PATA uses for SCSI, to be utilized with
>>libata. 
> 
> 
> What, if any mechanism supports changing the underlying write cache?  
> 
> That is, assuming this is common across PATA and SCSI drives, and it is 
> possible to turn the cache off on the IDE drives, would switching the 
> cache underneath require completing the inflight IO?

[ignoring your question, but it made me think...]


I am thinking the barrier support should know if the write cache is 
disabled (some datacenters do this), and avoid flushing if so?

	Jeff



  reply	other threads:[~2005-01-27 23:01 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-27 12:02 [PATCH] scsi/sata write barrier support Jens Axboe
2005-01-27 15:08 ` [PATCH] scsi/sata write barrier support #2 Jens Axboe
2005-01-27 23:02   ` Jeff Garzik
2005-01-27 22:42 ` [PATCH] scsi/sata write barrier support Doug Maxey
2005-01-27 23:00   ` Jeff Garzik [this message]
2005-01-28  6:54     ` Jens Axboe
2005-01-28  8:10       ` Jeff Garzik
2005-01-28  8:18         ` Jens Axboe
2005-01-28  9:38           ` Jens Axboe
2005-01-28 13:06             ` James Bottomley
2005-01-28 13:10               ` Jens Axboe
2005-01-28 13:12             ` James Bottomley
2005-01-28  6:58   ` Jens Axboe
2005-02-22  4:42 ` Greg Stark
2005-02-22  7:13   ` Jens Axboe
2005-02-22 17:06     ` Greg Stark
2005-03-01  8:47       ` Jens Axboe
2005-03-01 15:55         ` Greg Stark

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