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From: Jeff Garzik <jgarzik@pobox.com>
To: Arvydas Sidorenko <asido4@gmail.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>, Jeff Garzik <jeff@garzik.org>,
	linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org,
	linux-scsi@vger.kernel.org, Zheng Liu <wenqing.lz@taobao.com>
Subject: Re: [RFC][PATCH] libata: enable SATA disk fua detection on default
Date: Sun, 09 Sep 2012 16:39:06 -0400	[thread overview]
Message-ID: <504CFE6A.6020403@pobox.com> (raw)
In-Reply-To: <CA+6av4mdQ3daHHakRDCmHR_zMfcA_cAoabSuwBrcfjpYgUcXyg@mail.gmail.com>

On 09/09/2012 04:34 PM, Arvydas Sidorenko wrote:
>> Meanwhile there already has a number of SATA disks that have supported
>> this feature.  So I think maybe we can enable it.
>>
>> Regards,
>> Zheng
>
> Blindly enabling FUA by default in my opinion is not a good idea at all.
> I believe the focus should be on detecting FUA support on the device
> instead, which the kernel at this point cannot reliably do (is it possible?).

Premature assumptions.  It is entirely possible that FUA is detected 
accurately, but the software is missing a flush somewhere that FUA 
requires, if disks are to be used in FUA mode.

The filesystem and the block layer must properly generate and order 
their I/Os based on the FUA enablement bits that appear in the block 
layer after libata discovers the SATA FUA feature.

	Jeff





  reply	other threads:[~2012-09-09 20:39 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-08  3:24 [RFC][PATCH] libata: enable SATA disk fua detection on default Zheng Liu
2012-05-09  5:38 ` Robert Hancock
2012-05-09  6:19   ` Zheng Liu
2012-05-09  8:25     ` Christoph Hellwig
2012-05-09  9:30       ` Zheng Liu
2012-05-09 11:12         ` Christoph Hellwig
2012-05-09 12:48           ` Zheng Liu
2012-05-09 13:20             ` Bernd Schubert
2012-05-09 13:23             ` Christoph Hellwig
2012-07-03  9:04 ` Zheng Liu
2012-07-03 20:11   ` Michael Tokarev
2012-07-04  2:47     ` Zheng Liu
2012-07-04  6:36       ` Michael Tokarev
2012-07-04  7:06         ` Zheng Liu
2012-09-09 20:34           ` Arvydas Sidorenko
2012-09-09 20:39             ` Jeff Garzik [this message]
2012-08-17 18:06 ` Enabling FUA for SATA drives (was Re: [RFC][PATCH] libata: enable SATA disk fua detection on default) Jeff Garzik

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