From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Amit Sahrawat <amit.sahrawat83@gmail.com>
Cc: Nam-Jae Jeon <namjae.jeon@samsung.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] scsi: retrieve cache mode using ATA_16 if normal routine fails
Date: Mon, 12 Dec 2011 16:51:07 +0400 [thread overview]
Message-ID: <1323694267.20451.5.camel@dabdike> (raw)
In-Reply-To: <1323688722-25400-1-git-send-email-amit.sahrawat83@gmail.com>
On Mon, 2011-12-12 at 16:48 +0530, Amit Sahrawat wrote:
> It has been observed that a number of USB HDD's do not respond correctly
> to SCSI mode sense command(retrieve caching pages) which results in their
> Write Cache being discarded by queue requests i.e., WCE if left set to
> '0'(disabled).
> This results in a number of Filesystem corruptions, when the device
> is unplugged abruptly.
Um, how would knowing the caching type correctly help? If you surprise
unplug the device, we can't send a flush to it anyway ...
> So, in order to identify the devices correctly - give it
> a last try using ATA_16 after failure from normal routine.
> Introduce a mechanism to store write-cache type using /sys/class/
> interface, so that the normal code continues to function without errors.
>
> Signed-off-by: Amit Sahrawat <amit.sahrawat83@gmail.com>
> Signed-off-by: Nam-Jae Jeon <namjae.jeon@samsung.com>
This whole patch looks like a layering violation. Why not just update
the SAT layer to translate the MODE SENSE correctly?
James
next prev parent reply other threads:[~2011-12-12 12:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-12 11:18 [PATCH 1/1] scsi: retrieve cache mode using ATA_16 if normal routine fails Amit Sahrawat
2011-12-12 12:51 ` James Bottomley [this message]
2011-12-13 0:20 ` Namjae Jeon
[not found] ` <CADDb1s2SOK5sC3N0OOdkBrPuDKc2d2A4z4yso4jYs=1rbxNmkA@mail.gmail.com>
2011-12-13 4:56 ` Amit Sahrawat
2011-12-13 8:53 ` James Bottomley
2011-12-13 12:15 ` Amit Sahrawat
2011-12-13 20:38 ` Jeff Garzik
2011-12-14 3:44 ` Amit Sahrawat
2011-12-14 7:39 ` James Bottomley
2011-12-15 0:25 ` Namjae Jeon
2012-01-27 5:20 ` Amit Sahrawat
-- strict thread matches above, loose matches on Subject: below --
2012-02-03 12:59 Amit Sahrawat
2012-02-05 12:05 ` Sergei Shtylyov
2012-02-06 5:40 ` Amit Sahrawat
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