Re: XFS Fails Quality Assurance Tests on ARM

From: Nick Piggin
Date: Fri Sep 28 2007 - 10:12:49 EST


On Sunday 02 September 2007 08:14, Andi Kleen wrote:
> David Miller <davem@xxxxxxxxxxxxx> writes:
> > From: Byron Bradley <byron.bbradley@xxxxxxxxx>
> > Date: Fri, 31 Aug 2007 03:12:46 +0000 (UTC)
> >
> > > Anybody got any ideas of how we fix this?
> >
> > I don't know how much testing XFS gets on ARM, but one thing that some
> > ARM chips have is D-cache aliasing problems and one thing XFS uses a
> > lot is virtual remapping of various data structures via vmap().
> >
> > This might be what is causing the problems.
>
> AFAIK XFS uses vmap() mainly during log replay. If David's theory
> was true then the failures must be seen during tests that do
> this.

I think it can also do vmap for directory lookups, and it crashed
in some directory lookup AFAIKS.

One way to verify would be to create the XFS filesystem with PAGE_SIZE
directory blocks (mkfs.xfs -nsize=PAGE_SIZE) I believe. Dave will correct
me if I'm wrong.

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