[PATCH 2/2] SUNRPC: Simplify svc_unregister()

Steve Dickson SteveD at redhat.com
Wed Feb 11 20:06:02 UTC 2009


We now have some evidence that PMAP_UNSET clears only "inet" entries,
and not "inet6" entries, in the rpcbind database.  The svc_unregister()
function also must work if user space doesn't support rpcbind version
4 at all.

Thus we'll send an rpcbind v4 UNSET, and if that fails, we'll send a
PMAP_UNSET.

This simplifies the code in svc_unregister() and provides better
backwards compatibility with legacy user space that does not support
rpcbind version 4.

This patch is part of a series that addresses
   http://bugzilla.kernel.org/show_bug.cgi?id=12256

Signed-off-by: Chuck Lever <chuck.lever at oracle.com>
Signed-off-by: Steve Dickson <steved at redhat.com>
---

 net/sunrpc/svc.c |   35 ++++++++++++++---------------------
 1 files changed, 14 insertions(+), 21 deletions(-)

diff -up linux-2.6.28.x86_64/net/sunrpc/svc.c.orig linux-2.6.28.x86_64/net/sunrpc/svc.c
--- linux-2.6.28.x86_64/net/sunrpc/svc.c.orig	2009-02-10 13:14:34.000000000 -0500
+++ linux-2.6.28.x86_64/net/sunrpc/svc.c	2009-02-11 15:02:14.000000000 -0500
@@ -903,15 +903,25 @@ int svc_register(const struct svc_serv *
 }
 
 /*
- * Olaf says a v2 UNSET should clear _all_ entries, including any
- * registered via a v4 SET
+ * If user space is running rpcbind, it should take the v4 UNSET
+ * and clear everything for this [program, version].  If user space
+ * is running portmap, it will reject the v4 UNSET, but won't have
+ * any "inet6" entries anyway.  So a PMAP_UNSET should be sufficient
+ * in this case to clear all existing entries for [program, version].
  */
 static void __svc_unregister(const u32 program, const u32 version,
 			     const char *progname)
 {
 	int error;
 
-	error = rpcb_register(program, version, 0, 0);
+	/*
+	 * User space didn't support rpcbind v4, so retry this
+	 * request with the legacy rpcbind v2 protocol.
+	 */
+	error = rpcb_v4_register(program, version, NULL, "");
+	if (error == -EPROTONOSUPPORT)
+		error = rpcb_register(program, version, 0, 0);
+
 	dprintk("svc: %s(%sv%u), error %d\n",
 			__func__, progname, version, error);
 }




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