NFS: Configure support for netfs when NFS fscache is configured

As first steps for support of the netfs library when NFS_FSCACHE is
configured, add NETFS_SUPPORT to Kconfig and add the required netfs_inode
into struct nfs_inode.

Using netfs requires we move the VFS inode structure to be stored
inside struct netfs_inode, along with the fscache_cookie.
Thus, if NFS_FSCACHE is configured, place netfs_inode inside an
anonymous union so the vfs_inode memory is the same and we do
not need to modify other non-fscache areas of NFS.
In addition, inside the NFS fscache code, use the new helpers,
netfs_inode() and netfs_i_cookie() helpers, and remove our own
helper, nfs_i_fscache().

Later patches will convert NFS fscache to fully use netfs.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-by: Daire Byrne <daire@dneg.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 10 insertions, 14 deletions

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index bf89fe6fc3ba..041e79a48f7a 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -31,6 +31,10 @@
 #include <linux/sunrpc/auth.h>
 #include <linux/sunrpc/clnt.h>
 
+#ifdef CONFIG_NFS_FSCACHE
+#include <linux/netfs.h>
+#endif
+
 #include <linux/nfs.h>
 #include <linux/nfs2.h>
 #include <linux/nfs3.h>
@@ -204,14 +208,15 @@ struct nfs_inode {
 	/* how many bytes have been written/read and how many bytes queued up */
 	__u64 write_io;
 	__u64 read_io;
-#ifdef CONFIG_NFS_FSCACHE
-	struct fscache_cookie	*fscache;
-#endif
-	struct inode		vfs_inode;
-
 #ifdef CONFIG_NFS_V4_2
 	struct nfs4_xattr_cache *xattr_cache;
 #endif
+	union {
+		struct inode		vfs_inode;
+#ifdef CONFIG_NFS_FSCACHE
+		struct netfs_inode	netfs; /* netfs context and VFS inode */
+#endif
+	};
 };
 
 struct nfs4_copy_state {
@@ -329,15 +334,6 @@ static inline int NFS_STALE(const struct inode *inode)
 	return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
 }
 
-static inline struct fscache_cookie *nfs_i_fscache(struct inode *inode)
-{
-#ifdef CONFIG_NFS_FSCACHE
-	return NFS_I(inode)->fscache;
-#else
-	return NULL;
-#endif
-}
-
 static inline __u64 NFS_FILEID(const struct inode *inode)
 {
 	return NFS_I(inode)->fileid;