From: Christoph Hellwig <hch@infradead.org>
To: Douglas Gilbert <dgilbert@interlog.com>
Cc: Christoph Hellwig <hch@infradead.org>,
SCSI development list <linux-scsi@vger.kernel.org>,
Dan Hor??k <dhorak@redhat.com>
Subject: Re: SYNCHRONIZE CACHE command from sd on close
Date: Fri, 19 Feb 2010 03:04:07 -0500 [thread overview]
Message-ID: <20100219080407.GA21905@infradead.org> (raw)
In-Reply-To: <4B7DD949.3010907@interlog.com>
On Fri, Feb 19, 2010 at 01:20:25AM +0100, Douglas Gilbert wrote:
> So send a START_STOP_UNIT(stop) through the SG_IO
> ioctl on a sd device opened RW and as a bonus get
> three INQUIRYs (one standard, two VPD pages) and 5 READ
> commands!
>
> If the device is SCSI (as the scsi_debug driver is
> simulating) then those READs fail because the drive
> is stopped. However if that is an ATA disk behind a
> SAT layer, then the disk will be spun up. That defeats
> the purpose of the pass-though, especially when it
> is being used to spin down the disk.
>
> My guess, reviewing the bug reports flowing into me is
> that this nonsense started around lk 2.6.29 .
We should never send INQUIRY or READ commands from the kernel
in response to opening a device. But the combination sounds
like something udev might be doing for it's stable device
indentifier and manual partition scan because I don't trust
the kernel thing. Can you check if these commands come from
udev or one of the realted tools (hal, device-kit-blah, udisks
whatever it is called today)
next prev parent reply other threads:[~2010-02-19 8:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-15 13:03 SYNCHRONIZE CACHE command from sd on close Douglas Gilbert
2010-02-15 13:25 ` Christoph Hellwig
2010-02-15 13:51 ` Douglas Gilbert
2010-02-15 22:48 ` Christoph Hellwig
2010-02-19 0:20 ` Douglas Gilbert
2010-02-19 8:04 ` Christoph Hellwig [this message]
2010-02-19 11:56 ` Douglas Gilbert
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