Re: [PATCH: 2.6.20-rc4-mm1] JFS: Avoid deadlock introduced by explicit I/O plugging

From: Jens Axboe
Date: Wed Jan 17 2007 - 18:48:45 EST


On Wed, Jan 17 2007, Dave Kleikamp wrote:
> On Thu, 2007-01-18 at 10:18 +1100, Jens Axboe wrote:
>
> > Can you try io_schedule() and verify that things just work?
>
> I actually did do that in the first place, but wondered if it was the
> right thing to introduce the accounting changes that came with that.
> I'll change it back to io_schedule() and test it again, just to make
> sure.

It appears to be the correct change to me - you really are waiting for
IO resources (otherwise it would not hang with the plug change), so
doing an inc/dec of iowait around the schedule should be done.

> If that's the right fix, I can push it directly since it won't have any
> dependencies on your patches.

Perfect!

--
Jens Axboe

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