Date: Fri, 17 Nov 2006 10:23:49 +1100
From: David Chinner <dgc@sgi.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: David Chinner <dgc@sgi.com>, Pavel Machek <pavel@ucw.cz>,
       Alasdair G Kergon <agk@redhat.com>, Eric Sandeen <sandeen@redhat.com>,
       Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org,
       dm-devel@redhat.com, Srinivasa DS <srinivasa@in.ibm.com>,
       Nigel Cunningham <nigel@suspend2.net>
Subject: Re: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex
Message-ID: <20061116232349.GI11034@melbourne.sgi.com>
References: <20061107183459.GG6993@agk.surrey.redhat.com> <20061110103942.GG3196@elf.ucw.cz> <20061112223012.GH11034@melbourne.sgi.com> <200611122343.06625.rjw@sisk.pl>
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On Sun, Nov 12, 2006 at 11:43:05PM +0100, Rafael J. Wysocki wrote:
> On Sunday, 12 November 2006 23:30, David Chinner wrote:
> > And how does freezing them at that point in time guarantee consistent
> > filesystem state?
> 
> If the work queues are frozen, there won't be any fs-related activity _after_
> we create the suspend image. 

fs-related activity before or after the suspend image is captured is
not a problem - it's fs-related activity _during_ the suspend that
is an issue here. If we have async I/O completing during the suspend
image capture, we've got problems....

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group
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