Re: nfsd Security: /// bad export. error

Philippe Troin (phil@fifi.org)
20 Sep 1999 01:55:47 -0700


"G. Allen Morris III" <gam3@ixlabs.com> writes:

> >>>Philippe Troin said:
> > Mmmh, I think there's something more subtle going on.
> > The problem lasts a few seconds where all fh lookups fail, and after
> > that everything is back to normal... If the original dentry were
> > flushed out, the problem would persist.
>
> The reason that it does not persist is that after nfsd walks up the
> tree to the root it walks back down (using the path it just built)
> to the dirino. So the next time you walk up the dentry you find
> the export dentry.

I'm not sure I understand what you mean here...
The walk up happens in fh_verify by following dentry->d_parent.
But the export ex_dentry pointer never gets updated AFAIK.

How can two dentries referencing the same point in the fs can co-exist
in the same kernel ?

> > Plus, I think the export structure keeps the dentry locked.
>
> But only the export is pinned. The other directories aren't.

True.

Phil.

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