Date: Fri, 18 Apr 1997 11:11:30 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: ponds!rivers@dg-rtp.dg.com Cc: freebsd-bugs@freefall.freebsd.org Subject: Re: kern/3304: NFS V2 readdir hangs Message-ID: <199704180911.LAA08276@labinfo.iet.unipi.it> In-Reply-To: <199704180230.TAA25674@freefall.freebsd.org> from "Thomas David Rivers" at Apr 17, 97 07:29:45 pm
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Hi,
I followed the interesting (and very detailed) analysis of the NFS
problem (PR kern/3304), and I have a possible patch.
looking at nfs_rcvlock() is implemented, I notice that the only way to
return EALREADY is to have rep->r_mrep != NULL
The variable comes (via nfs_reply() ) from nfs_request() where the code
is something like the following (I have reported only a few relevant
lines, from a 2.2.1-R system:
$Id: nfs_socket.c,v 1.18 1996/10/11 10:15:33 dfr Exp $
923: tryagain:
...
933: rep->r_mrep = NULL;
...
979: error = nfs_reply(rep);
...
1064: goto tryagain;
the problem is, r_mrep seems only to be set to something != NULL in
nfs_reply(). While I don't understand the code very well, it seems
to me that the initialization in line 933 should be moved outside
the retry loop, before line 923. Otherwise the locking cannot possibly
work because repeated calls to nfs_reply() use the same parameters.
Can someone (Dave ?) try the above fix and see if it works ?
Thanks
Luigi
-----------------------------+--------------------------------------
Luigi Rizzo | Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it | Universita' di Pisa
tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/
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