PLEASE TEST: IPI deadlock avoidance patch

[Daniel Eriksson]

I wrote:

> Running the exact same test under a kernel compiled without
> SMP worked without any problems.

Hmm, after running the test a second time, I actually got a crc error even
when using a UP kernel. The test set is 9GB+ in ~270 files. With SMP I seem
to get around 10% corrupt files after simply making a duplicate of the
folder. With UP I have gotten 1 corrupt file in 2 tries (~550 files copied).

I'll report back here after I have tested "classic" vinum.

/Daniel Eriksson