From: Hannes Reinecke <hare@suse.de>
To: Oliver Neukum <oliver@neukum.org>
Cc: SCSI Mailing List <linux-scsi@vger.kernel.org>
Subject: Re: question on SDEV_BLOCK vs. SDEV_QUIESCE
Date: Tue, 25 Sep 2007 09:42:36 +0200 [thread overview]
Message-ID: <46F8BBEC.4090602@suse.de> (raw)
In-Reply-To: <200709250934.30213.oliver@neukum.org>
Oliver Neukum wrote:
> Hi,
>
> what is the difference between these states? What function should
> I call to block a device in order to securely flush the caches?
>
SDEV_BLOCK blocks _any_ commands from the midlayer; eg. if the LLDD
is doing some internal recovery.
SDEV_QUIESCE only blocks 'normal' data commands; others (like control
commands) can still get through.
So for flushing you should use SDEV_QUIESCE.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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next prev parent reply other threads:[~2007-09-25 7:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-25 7:34 question on SDEV_BLOCK vs. SDEV_QUIESCE Oliver Neukum
2007-09-25 7:42 ` Hannes Reinecke [this message]
2007-09-25 7:56 ` Oliver Neukum
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