failing LOCK1 smbtorture test

[Anton Blanchard]

Hi,

> 	I'm thinking the best thing to do might be to expand
> the tests/shared_mmap.c code to also test for a coherent mmap/
> read/write cache, and report a non-working mmap if this fails.

There are other mmap bugs that will be very hard to check for, maybe
we need a blacklist.

For example Tridge and I found a bug in the sparc32/64 linux shared
mmap code. It turns out we were allocating addresses for the tdb mmap
at different virtual colours.

This means that we could have two cache lines mapping to the same
physical address. Under just the right conditions (two processes with
the tdb mmap mapped at different virtual colours, most likely SMP,
both hitting the same part of the mmap at the same time) we would corrupt
the tdb.

I fixed this but older 2.2 and 2.4 sparc kernels will still have this
problem.

Anton