NFS: Add version registering framework

This patch adds in the code to track multiple versions of the NFS
protocol.  I created default structures for v2, v3 and v4 so that each
version can continue to work while I convert them into kernel modules.
I also removed the const parameter from the rpc_version array so that I
can change it at runtime.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/fs/nfs/nfs.h b/fs/nfs/nfs.h
new file mode 100644
index 00000000000..ac10b9e6c92
--- /dev/null
+++ b/fs/nfs/nfs.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2012 Netapp, Inc. All rights reserved.
+ *
+ * Function and structures exported by the NFS module
+ * for use by NFS version-specific modules.
+ */
+#ifndef __LINUX_INTERNAL_NFS_H
+#define __LINUX_INTERNAL_NFS_H
+
+#include <linux/fs.h>
+#include <linux/sunrpc/sched.h>
+#include <linux/nfs_xdr.h>
+
+struct nfs_subversion {
+	struct module *owner;	/* THIS_MODULE pointer */
+	struct file_system_type *nfs_fs;	/* NFS filesystem type */
+	const struct rpc_version *rpc_vers;	/* NFS version information */
+	const struct nfs_rpc_ops *rpc_ops;	/* NFS operations */
+	struct list_head list;		/* List of NFS versions */
+};
+
+int nfs_register_versions(void);
+void nfs_unregister_versions(void);
+
+#ifdef CONFIG_NFS_V2
+int init_nfs_v2(void);
+void exit_nfs_v2(void);
+#else /* CONFIG_NFS_V2 */
+static inline int __init init_nfs_v2(void)
+{
+	return 0;
+}
+
+static inline void exit_nfs_v2(void)
+{
+}
+#endif /* CONFIG_NFS_V2 */
+
+#ifdef CONFIG_NFS_V3
+int init_nfs_v3(void);
+void exit_nfs_v3(void);
+#else /* CONFIG_NFS_V3 */
+static inline int __init init_nfs_v3(void)
+{
+	return 0;
+}
+
+static inline void exit_nfs_v3(void)
+{
+}
+#endif /* CONFIG_NFS_V3 */
+
+#ifdef CONFIG_NFS_V4
+int init_nfs_v4(void);
+void exit_nfs_v4(void);
+#else /* CONFIG_NFS_V4 */
+static inline int __init init_nfs_v4(void)
+{
+	return 0;
+}
+
+static inline void exit_nfs_v4(void)
+{
+}
+#endif /* CONFIG_NFS_V4 */
+
+struct nfs_subversion *get_nfs_version(unsigned int);
+void put_nfs_version(struct nfs_subversion *);
+void register_nfs_version(struct nfs_subversion *);
+void unregister_nfs_version(struct nfs_subversion *);
+
+#endif /* __LINUX_INTERNAL_NFS_H */