NFS: Register NFS for caching and retrieve the top-level index

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

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>

4 files changed, 93 insertions, 0 deletions

diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index ac6170c594a3..0e0bb6c17a86 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -15,3 +15,4 @@ nfs-$(CONFIG_NFS_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \
                            callback.o callback_xdr.o callback_proc.o \
                            nfs4namespace.o
 nfs-$(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 000000000000..6d5bb5c69048
--- /dev/null
+++ b/fs/nfs/fscache-index.c
@@ -0,0 +1,49 @@
+/* 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
+
+/*
+ * Define the NFS filesystem for FS-Cache.  Upon registration FS-Cache sticks
+ * the cookie for the top-level index object for NFS into here.  The top-level
+ * index can than have other cache objects inserted into it.
+ */
+struct fscache_netfs nfs_fscache_netfs = {
+        .name           = "nfs",
+        .version        = 0,
+};
+
+/*
+ * Register NFS for caching
+ */
+int nfs_fscache_register(void)
+{
+        return fscache_register_netfs(&nfs_fscache_netfs);
+}
+
+/*
+ * Unregister NFS for caching
+ */
+void nfs_fscache_unregister(void)
+{
+        fscache_unregister_netfs(&nfs_fscache_netfs);
+}
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
new file mode 100644
index 000000000000..ccfcdc58066e
--- /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_fscache_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 a834d1d850b7..cd29f410e941 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
 
@@ -1436,6 +1437,10 @@ static int __init init_nfs_fs(void)
 {
         int err;
 
+        err = nfs_fscache_register();
+        if (err < 0)
+                goto out7;
+
         err = nfsiod_start();
         if (err)
                 goto out6;
@@ -1488,6 +1493,8 @@ out4:
 out5:
         nfsiod_stop();
 out6:
+        nfs_fscache_unregister();
+out7:
         return err;
 }
 
@@ -1498,6 +1505,7 @@ 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