[dm-devel] Block regression since 3.1-rc3

[Christophe Saout]

Hello again,

> Today I was trying to boot a new 3.1 RC kernel on one of our server
> machines and ran into a weird block-related crash.
> 
> Whenever I was trying to access some filesystem on the external RAID, I
> would soon run into the crash seen below, followed by a total lockup a
> bit later.
> 
> The external RAID is accessed via multipath and simple logical volumes
> on top. [...]
>
> The bug seems to be introduced between rc2 and rc3. Up to rc2 everything
> is fine, and rc3 and also the latest kernel shows this bug. From the git
> log I can see that the block/ directory has seen some larger update, but
> this is just a wild guess.

Actually, I just found out that reverting

commit 4853abaae7e4a2af938115ce9071ef8684fb7af4
Author: Jeff Moyer <jmoyer at redhat.com>
Date:   Mon Aug 15 21:37:25 2011 +0200

    block: fix flush machinery for stacking drivers with differring flush flags

makes the problem disappear.

Let me know if I can help with further information.

Cheers,
	Christophe