nfsd: add a per-net-namespace struct for nfsd

Eventually, we'll need this when nfsd gets containerized fully. For
now, create a struct on a per-net-namespace basis that will just hold
a pointer to the cld_net structure. That struct will hold all of the
per-net data that we need for the cld tracker.

Eventually we can add other pernet objects to struct nfsd_net.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/netns.h

+/*
+ * per net namespace data structures for nfsd
+ *
+ * Copyright (C) 2012, Jeff Layton <jlayton@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __NFSD_NETNS_H__
+#define __NFSD_NETNS_H__
+
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+struct cld_net;
+
+struct nfsd_net {
+	struct cld_net *cld_net;
+};
+
+extern int nfsd_net_id;
+#endif /* __NFSD_NETNS_H__ */

fs/nfsd/nfsctl.c

@@ -19,6 +19,7 @@
 #include "nfsd.h"
 #include "cache.h"
 #include "fault_inject.h"
+#include "netns.h"
 
 /*
  *	We have a single directory with several nodes in it.
@@ -1124,14 +1125,23 @@ static int create_proc_exports_entry(void)
 }
 #endif
 
+int nfsd_net_id;
+static struct pernet_operations nfsd_net_ops = {
+	.id   = &nfsd_net_id,
+	.size = sizeof(struct nfsd_net),
+};
+
 static int __init init_nfsd(void)
 {
 	int retval;
 	printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n");
 
+	retval = register_pernet_subsys(&nfsd_net_ops);
+	if (retval < 0)
+		return retval;
 	retval = nfsd4_init_slabs();
 	if (retval)
-		return retval;
+		goto out_unregister_pernet;
 	nfs4_state_init();
 	retval = nfsd_fault_inject_init(); /* nfsd fault injection controls */
 	if (retval)
@@ -1169,6 +1179,8 @@ static int __init init_nfsd(void)
 	nfsd_fault_inject_cleanup();
 out_free_slabs:
 	nfsd4_free_slabs();
+out_unregister_pernet:
+	unregister_pernet_subsys(&nfsd_net_ops);
 	return retval;
 }
 
@@ -1184,6 +1196,7 @@ static void __exit exit_nfsd(void)
 	nfsd4_free_slabs();
 	nfsd_fault_inject_cleanup();
 	unregister_filesystem(&nfsd_fs_type);
+	unregister_pernet_subsys(&nfsd_net_ops);
 }
 
 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");