[Pvfs2-users] pvfs2 on debian running on sparc hardware

[Robert Latham]

On Fri, May 26, 2006 at 11:13:07AM -0700, Yan Lam wrote:
> I'm having problem with pvfs2 running kernel 2.6.16 on sparc
> architecture.  I complied the 1.4.0 source code and everything compiled
> without any errors.  However when I load the kernel module, it
> complaints about unknown symbol flush_ptrace_access and update_atime.

Hi

None of us have access to a sparc machine, so we don't get to test
this very often.  Thanks for reporting your problems.

the 'update_atime' problem we know about and have fixed in CVS.  
The symbol 'flush_ptrace_access', however, appears to be sparc64 only.

The 'cacheflush.h' header uses that symbol in two macros:
copy_to_user_page and copy_from_user_page

It looks like the sparc kernel does not export the flush_ptrace_access
symobl, even though its header files expose it to any routine that
calls copy_to_user_page or copy_from_user_page.  I'd say this is a bug
but can we work around it?

It turns out we can.  If you configure pvfs2 with the
--disable-kernel-aio option, then the PVFS2 kernel module will  use an
alternate code path that might be a bit slower, but will not bring in
any un-exported symbols.   You'll still have to work with CVS to get
around the update_atime problem, but with these two changes you'll be
on your way.

> Any idea on what I am missing?

You are missing nothing.  Thanks for the report, and we will update
our documentation.  Hopefully the sparc64 kernel guys will add
flush_ptrace_access' to the list of exported symbols in the next
kernel release.

I should warn you that a few years ago someone trying to run pvfs2 on
a sparc III got a lot of SIGBUS errors when pvfs2 would carry out an
unaligned memory access.   Since then, we have eliminated a lot of
unalinged accesses, but there might still be a few lurking around.
Let us know if you run into anything like that.

Thanks
==rob

-- 
Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Labs, IL USA                B29D F333 664A 4280 315B