[PATCH] PATCH - knfsd fixes for 2.5.6

Fix a few kNFSd problems.

1/ export svc_reserve which was introduced for NFS/TCP support.
    Without this we cannot load nfsd.o as a module
2/ the hash chain of clients was being changed (to put the found
   entry at the top of the list) while we only had a read-lock.
   This could corrupt the list and cause big problems.
   For now, just disable this code.  Might add a lock later...
3/ lockd was calling exp_getclient without getting a readlock
   on the export table first.
4/ Add Config.help entry for CONFIG_NFSD_TCP

fs/Config.help

@@ -561,6 +561,10 @@ CONFIG_NFSD_V3
   If you would like to include the NFSv3 server as well as the NFSv2
   server, say Y here.  If unsure, say Y.
 
+CONFIG_NFSD_TCP
+  Enable NFS service over TCP connections.  This the officially
+  still experimental, but seems to work well.
+
 CONFIG_HPFS_FS
   OS/2 is IBM's operating system for PC's, the same as Warp, and HPFS
   is the file system used for organizing files on OS/2 hard disk

fs/lockd/svc4proc.c

@@ -447,11 +447,13 @@ nlm4svc_proc_sm_notify(struct svc_rqst *rqstp, struct nlm_reboot *argp,
 	if (nlmsvc_ops != NULL) {
 		struct svc_client	*clnt;
 		saddr.sin_addr.s_addr = argp->addr;
+		nlmsvc_ops->exp_readlock();
 		if ((clnt = nlmsvc_ops->exp_getclient(&saddr)) != NULL 
 		 && (host = nlm_lookup_host(clnt, &saddr, 0, 0)) != NULL) {
 			nlmsvc_free_host_resources(host);
 		}
 		nlm_release_host(host);
+		nlmsvc_ops->exp_unlock();
 	}
 
 	return rpc_success;

fs/lockd/svcproc.c

@@ -475,11 +475,13 @@ nlmsvc_proc_sm_notify(struct svc_rqst *rqstp, struct nlm_reboot *argp,
 	if (nlmsvc_ops != NULL) {
 		struct svc_client	*clnt;
 		saddr.sin_addr.s_addr = argp->addr;	
+		nlmsvc_ops->exp_readlock();
 		if ((clnt = nlmsvc_ops->exp_getclient(&saddr)) != NULL 
 		 && (host = nlm_lookup_host(clnt, &saddr, 0, 0)) != NULL) {
 			nlmsvc_free_host_resources(host);
 		}
 		nlm_release_host(host);
+		nlmsvc_ops->exp_unlock();
 	}
 
 	return rpc_success;

fs/nfsd/export.c

@@ -455,13 +455,19 @@ exp_getclient(struct sockaddr_in *sin)
 
 	for (hp = head; (tmp = *hp) != NULL; hp = &(tmp->h_next)) {
 		if (tmp->h_addr.s_addr == addr) {
+#if 0
+/* If we really want to do this, we need a spin
+lock to protect against multiple access (as we only
+have an exp_readlock) and need to protect
+the code in e_show() that walks this list too.
+*/
 			/* Move client to the front */
 			if (head != hp) {
 				*hp = tmp->h_next;
 				tmp->h_next = *head;
 				*head = tmp;
 			}
-
+#endif
 			return tmp->h_client;
 		}
 	}

net/sunrpc/sunrpc_syms.c

@@ -77,6 +77,7 @@ EXPORT_SYMBOL(svc_process);
 EXPORT_SYMBOL(svc_recv);
 EXPORT_SYMBOL(svc_wake_up);
 EXPORT_SYMBOL(svc_makesock);
+EXPORT_SYMBOL(svc_reserve);
 
 /* RPC statistics */
 #ifdef CONFIG_PROC_FS