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Date: Sat, 14 Dec 2013 12:55:18 +1100
From: Dave Chinner <david@fromorbit.com>
To: Nigel Cunningham <nigel@nigelcunningham.com.au>
Cc: Tejun Heo <tj@kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Jens Axboe <axboe@kernel.dk>, tomaz.solc@tablix.org,
        aaron.lu@intel.com, linux-kernel@vger.kernel.org,
        Oleg Nesterov <oleg@redhat.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [PATCH] libata, freezer: avoid block device removal while system
 is frozen
Message-ID: <20131214015518.GQ31386@dastard>
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On Sat, Dec 14, 2013 at 10:15:21AM +1100, Nigel Cunningham wrote:
> Hi again.
> 
> On 14/12/13 10:07, Tejun Heo wrote:
> >Hello, Nigel.
> >
> >On Sat, Dec 14, 2013 at 09:45:59AM +1100, Nigel Cunningham wrote:
> >>In your first email, in the first substantial paragraph (starting
> >>"Now, if the rest.."), you say "libata device removal waits for the
> >>scheduled writeback work item to finish". I wonder if that's the
> >>lynchpin. If we know the device is gone, why are we trying to write
> >>to it?
> >It's just a standard part of block device removal -
> >invalidate_partition(), bdi_wb_shutdown().
> Mmm. But perhaps there needs to be some special code in there to
> handle the "we can't write to this device anymore" case?

I've been asking for that "special code" for years, Nigel... :/

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com