Re: nfs_lookup() panic, again

2011-10-09 Thread Greg Troxel

I'm not David, but:

I would also suggest tcpdumping to a file the nfs traffic, on some other
machine (perhaps the osx box) and then when the panic happens look at
the last few transactions to see if you spot anything odd.


There's a cache of name translations (used for namei), maintained by
code in sys/kern/vfs_cache.c.

As far as I can tell from what you posted and reading the code for not
quite long enough to be sure, the problem is that the plan for NFS is
for clients to short-circuit the . entry, and that therefore there's a
KASSERT that the looked-up answer (*vpp) isn't the same vnode as the
directory (dvp).

In your case, cnp is ...  At the root of a regular fs .. is ., so
I suspect that may have something to do with it.

For a mounted filesystem, .. on the root is supposed to go back to the
directory holding the mount point, but I don't know how that surgery is
done.

And, the current operation is mkdir.

Also, I wonder if the problem is that the cache is stale, and that the
invariant only holds on non-stale entries.

I would modify nfs_cache_enter to have a KASSERT(dvp != vp) and see what
happens.


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Re: nfs_lookup() panic, again

2011-10-09 Thread Emmanuel Dreyfus
Hubert Feyrer hub...@feyrer.de wrote:

 The setup of this is NetBSD-current/i386 in VMware Fusion with sources
 mounted via NFS from a Mac OS X NFS server. 

FWIW, I had many panics on a netbsd-5/i386 NFS server with MacOS X
clients. It ran fine the day I removed the mac clients (it was still
servicing NetBSD clients). A few weeks ago, it started doing panics
again. Updating to latest netbsd-5 with NBMCLUSTERS=16384 seems to spare
the problems, it did not crashed so far.

The machine has ddb.onpanic=0 and the dump device was badly configured
until the latest kernel update, so I have no panic message to share. I
can just concur that there is definitvely a bad story with MacOS X
clients and NetBSD NFS servers.

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
m...@netbsd.org