[PATCH] Do not cache NFSv2 readdir replies

[PATCH] Do not cache NFSv2 readdir replies

[Olaf Kirch]

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Hi,

we're currently caching NFSv2 readdir replies, even though the code uses
xdr pages to store the directories entries. As a result, we only cache
the NFS status and none of the entries, the cookie or the EOF flag.
Retransmitted NFSv2 readdir calls will see garbage replies.

(In case you're wondering why, I just had the pleasure of diagnosing a
rather interesting NFS problem with a POS system that used a homebrew
NFSv2 client that reused XIDs quite liberally and fell over when they
ran into this. Hard to believe, but there are NFS clients more bizarre
than zOS :-)

Please find attached the patch against 2.6.11-rc

Olaf
-- 
Olaf Kirch   |  --- o --- Nous sommes du soleil we love when we play
okir@suse.de |    / | \   sol.dhoop.naytheet.ah kin.ir.samse.qurax

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From: Olaf Kirch <okir@suse.de>
Subject: Do not cache NFSv2 readdir replies

nfsd would put incomplete readdir replies in the reply cache,
so that incomplete replies are returned in response to retransmitted
READDIR calls.

Signed-off-by: okir@suse.de

Index: linux-2.6.5/fs/nfsd/nfsproc.c
===================================================================
--- linux-2.6.5.orig/fs/nfsd/nfsproc.c	2005-01-27 17:32:42.000000000 +0100
+++ linux-2.6.5/fs/nfsd/nfsproc.c	2005-02-07 13:41:36.000000000 +0100
@@ -539,7 +539,7 @@ static struct svc_procedure		nfsd_proced
   PROC(symlink,	 symlinkargs,	void,		none,		RC_REPLSTAT, ST),
   PROC(mkdir,	 createargs,	diropres,	fhandle,	RC_REPLBUFF, ST+FH+AT),
   PROC(rmdir,	 diropargs,	void,		none,		RC_REPLSTAT, ST),
-  PROC(readdir,	 readdirargs,	readdirres,	none,		RC_REPLBUFF, 0),
+  PROC(readdir,	 readdirargs,	readdirres,	none,		RC_NOCACHE, 0),
   PROC(statfs,	 fhandle,	statfsres,	none,		RC_NOCACHE, ST+5),
 };