[dm-devel] [PATCH UPDATED 4/5] dm: implement REQ_FLUSH/FUA support for request-based dm
Mike Snitzer
snitzer at redhat.com
Thu Sep 2 03:22:46 UTC 2010
On Wed, Sep 01 2010 at 2:59pm -0400,
Mike Snitzer <snitzer at redhat.com> wrote:
> But we can meet in the middle. I've reordered the DM FLUSH+FUA patches
> so that the more intrusive bio-based relaxed ordering patch is at the
> very end.
>
> My hope was that the request-based deadlock I'm seeing would disappear
> if that relaxed ordering patch wasn't applied. Unfortunately, I still
> see the hang.
Turns out I can reproduce the hang on a stock 2.6.36-rc3 (without _any_
FLUSH+FUA patches)!
I'll try to pin-point the root cause but I think my test is somehow
exposing a bug in my virt setup.
So this hang is definitely starting to look like a red herring.
Tejun,
This news should clear the way for you to re-post your patches. I think
it would be best if you reordered the DM patches like I did here in this
series: http://people.redhat.com/msnitzer/patches/flush-fua/series
In particular, the dm-relax-ordering-of-bio-based-flush-implementation
patch should go at the end. I think it makes for a more logical
evolution of the DM code.
Thanks,
Mike
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