Re: 2.5.70-bk16: nfs crash

Dipankar Sarma (dipankar@in.ibm.com)
Fri, 13 Jun 2003 01:23:02 +0530


On Thu, Jun 12, 2003 at 09:26:29AM -0700, Trond Myklebust wrote:
> I still need a real fix for d_move(). In addition, I'm getting worried

Linus' fix allowing unhashed src dentries seems ok, if that is what
you are looking for.

> about the changes in functionality that you've introduced here. It
> seems to me that your lockless scheme opens for a *lot* of races:
>
> Look at all those functions that take dcache_lock, and then test
> dentry->d_count. Unless I'm missing something here, your d_lookup()
> clearly has them all screwed, no?

Not necessarily. One example is the fact that d_lookup() can
only increase d_count. Besides, dput() decrements d_count
without dcache_lock, so I am not sure holding dcache_lock during
d_count test buys you much.

We will do some audit tomorrow and see if there are issues here.

Thanks
Dipankar
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