[PATCH 24/37] NFS: Register NFS for caching and retrieve the top-level index [ver #34]

[David Howells <dhowells@redhat.com>]

Register NFS for caching and retrieve the top-level cache index object cookie.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/nfs/Makefile        |    1 +
 fs/nfs/fscache-index.c |   53 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/nfs/fscache.h       |   35 ++++++++++++++++++++++++++++++++
 fs/nfs/inode.c         |    8 +++++++
 4 files changed, 97 insertions(+), 0 deletions(-)
 create mode 100644 fs/nfs/fscache-index.c
 create mode 100644 fs/nfs/fscache.h


diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index df0f41e..6d7176d 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -16,3 +16,4 @@ nfs-$(CONFIG_NFS_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \
 			   nfs4namespace.o
 nfs-$(CONFIG_NFS_DIRECTIO) += direct.o
 nfs-$(CONFIG_SYSCTL) += sysctl.o
+nfs-$(CONFIG_NFS_FSCACHE) += fscache-index.o
diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c
new file mode 100644
index 0000000..225ed5d
--- /dev/null
+++ b/fs/nfs/fscache-index.c
@@ -0,0 +1,53 @@
+/* NFS FS-Cache index structure definition
+ *
+ * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_fs_sb.h>
+#include <linux/in6.h>
+
+#include "internal.h"
+#include "fscache.h"
+
+#define NFSDBG_FACILITY		NFSDBG_FSCACHE
+
+static const struct fscache_netfs_operations nfs_cache_ops = {
+};
+
+/*
+ * Define the NFS filesystem for FS-Cache.  Upon registration FS-Cache sticks
+ * the cookie for the top-level index object for NFS into this structure.  The
+ * top-level index can than have other cache objects inserted into it.
+ */
+struct fscache_netfs nfs_cache_netfs = {
+	.name		= "nfs",
+	.version	= 0,
+	.ops		= &nfs_cache_ops,
+};
+
+/*
+ * Register NFS for caching
+ */
+int nfs_fscache_register(void)
+{
+	return fscache_register_netfs(&nfs_cache_netfs);
+}
+
+/*
+ * Unregister NFS for caching
+ */
+void nfs_fscache_unregister(void)
+{
+	fscache_unregister_netfs(&nfs_cache_netfs);
+}
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
new file mode 100644
index 0000000..74ab060
--- /dev/null
+++ b/fs/nfs/fscache.h
@@ -0,0 +1,35 @@
+/* NFS filesystem cache interface definitions
+ *
+ * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _NFS_FSCACHE_H
+#define _NFS_FSCACHE_H
+
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+#include <linux/fscache.h>
+
+#ifdef CONFIG_NFS_FSCACHE
+
+/*
+ * fscache-index.c
+ */
+extern struct fscache_netfs nfs_cache_netfs;
+
+extern int nfs_fscache_register(void);
+extern void nfs_fscache_unregister(void);
+
+#else /* CONFIG_NFS_FSCACHE */
+static inline int nfs_fscache_register(void) { return 0; }
+static inline void nfs_fscache_unregister(void) {}
+
+#endif /* CONFIG_NFS_FSCACHE */
+#endif /* _NFS_FSCACHE_H */
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 966a885..7254d5c 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -46,6 +46,7 @@
 #include "delegation.h"
 #include "iostat.h"
 #include "internal.h"
+#include "fscache.h"
 
 #define NFSDBG_FACILITY		NFSDBG_VFS
 
@@ -1222,6 +1223,10 @@ static int __init init_nfs_fs(void)
 {
 	int err;
 
+	err = nfs_fscache_register();
+	if (err < 0)
+		goto out6;
+
 	err = nfs_fs_proc_init();
 	if (err)
 		goto out5;
@@ -1268,6 +1273,8 @@ out3:
 out4:
 	nfs_fs_proc_exit();
 out5:
+	nfs_fscache_unregister();
+out6:
 	return err;
 }
 
@@ -1278,6 +1285,7 @@ static void __exit exit_nfs_fs(void)
 	nfs_destroy_readpagecache();
 	nfs_destroy_inodecache();
 	nfs_destroy_nfspagecache();
+	nfs_fscache_unregister();
 #ifdef CONFIG_PROC_FS
 	rpc_proc_unregister("nfs");
 #endif