Subject: Re: [BUGFIX 2/2] gdth: bugfix for the Timer at exit crash
From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Boaz Harrosh <bharrosh@panasas.com>
Cc: Sven =?ISO-8859-1?Q?K=F6hler?= <skoehler@upb.de>,
       Christoph Hellwig <hch@infradead.org>, Jeff Garzik <jeff@garzik.org>,
       linux-scsi <linux-scsi@vger.kernel.org>, linux-kernel@vger.kernel.org,
       Joerg Dorchain <joerg@dorchain.net>,
       Jon Chelton <jchelton@ffpglobal.com>,
       Stefan Priebe - allied internet ag 
	<s.priebe@allied-internet.ag>
In-Reply-To: <47B31BDE.2030408@panasas.com>
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Date: Wed, 13 Feb 2008 10:45:22 -0600
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On Wed, 2008-02-13 at 18:33 +0200, Boaz Harrosh wrote:
> On Wed, Feb 13 2008 at 17:54 +0200, Boaz Harrosh <bharrosh@panasas.com> wrote:
> > On Wed, Feb 13 2008 at 17:44 +0200, James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
> >> On Tue, 2008-02-12 at 19:40 +0200, Boaz Harrosh wrote:
> >>> -	gdth_flush(ha);
> >>> -
> >> This piece doesn't look right.  gdth_flush() forces the internal cache
> >> to disk backing.  If you remove it, you're taking the chance that the
> >> machine will be powered off without a writeback which can cause data
> >> corruption.
> >>
> >> James
> >>
> > Yes. 
> > I have more problems reported, with exit, and am just sending one more patch that puts
> > this back in. Which was tested.
> > 
> > So I will resend this one plus one new one.
> > 
> > Boaz
> > 
> 
> The gdth driver would do a register_reboot_notifier(&gdth_notifier);
> to a gdth_halt() function, which would then redo half of what gdth_exit
> does, and wrongly so, and crash.  
> 
> Are we guaranteed in todays kernel that modules .exit function be called
> on an halt or reboot? If so then there is no need for duplications and
> the gdth_halt() should go.

No.  The __exit section is actually discardable if you promise never to
remove the module.

James


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