From: Christoph Hellwig <hch@infradead.org>
To: "Salyzyn, Mark" <mark_salyzyn@adaptec.com>
Cc: linux-scsi <linux-scsi@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH] dpt_i2o changes for 2.6.2 kernel in support of 64 bit and bitrot (part 1)
Date: Mon, 5 Apr 2004 21:47:03 +0100 [thread overview]
Message-ID: <20040405214703.A9782@infradead.org> (raw)
In-Reply-To: <547AF3BD0F3F0B4CBDC379BAC7E4189F64F204@otce2k03.adaptec.com>; from mark_salyzyn@adaptec.com on Mon, Apr 05, 2004 at 01:56:12PM -0400
On Mon, Apr 05, 2004 at 01:56:12PM -0400, Salyzyn, Mark wrote:
> We need a means for an application to tell if a scsi device is currently
> in use; one of in-error or with any I/O still pending or opened or
> mounted. This is necessary to inform users of the RAID management
> applications that the device is not to be adjusted.
We had this a few times already. If your applications wants to remove
a volume it'll do exactly that, and that's expected behaviour in unix
land where you have enough rope to shoot yourself in the foot.
> Unfortunately new members like struct scsi_disk::openers are
> inaccessible to the scsi driver to indicate whether there are any
> applications that have the scsi device open.
Which is intentional as the opencount of one particular upperlevel driver
has absolutely no meaning for a LLDD.
> Are there any suggestions, either for the application, or for the scsi
> driver to meter disk in-use?
The simple answer is: don't do it.
> Without this, it is *impossible* for us to
> support reliable native RAID management applications; a user application
> should *never* be a source of an OS panic (whether it be someone
> destroying the boot array, or simply a file system driver panicking when
> a device no longer exists)
A filesystem should not panic when the underlying device is offlines or
removed. At least XFS doesn't and if some other fs does file a bug
against it.
As for userland tools making the system unsuable, try a simple
cat /dev/zero > /dev/kmem
next prev parent reply other threads:[~2004-04-05 20:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-05 17:56 [PATCH] dpt_i2o changes for 2.6.2 kernel in support of 64 bit and bitrot (part 1) Salyzyn, Mark
2004-04-05 20:47 ` Christoph Hellwig [this message]
-- strict thread matches above, loose matches on Subject: below --
2004-04-06 14:47 Salyzyn, Mark
2004-04-06 14:03 Salyzyn, Mark
2004-04-06 14:17 ` Christoph Hellwig
2004-04-05 22:23 Salyzyn, Mark
2004-04-06 5:20 ` Christoph Hellwig
2004-04-06 14:48 ` Matthew Wilcox
2004-02-10 21:47 Salyzyn, Mark
2004-02-10 20:53 Salyzyn, Mark
2004-02-10 21:21 ` Christoph Hellwig
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