Embed a struct path into struct nameidata instead of nd->{dentry,mnt}

This is the central patch of a cleanup series. In most cases there is no good
reason why someone would want to use a dentry for itself. This series reflects
that fact and embeds a struct path into nameidata.

Together with the other patches of this series
- it enforced the correct order of getting/releasing the reference count on
  <dentry,vfsmount> pairs
- it prepares the VFS for stacking support since it is essential to have a
  struct path in every place where the stack can be traversed
- it reduces the overall code size:

without patch series:
   text    data     bss     dec     hex filename
5321639  858418  715768 6895825  6938d1 vmlinux

with patch series:
   text    data     bss     dec     hex filename
5320026  858418  715768 6894212  693284 vmlinux

This patch:

Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix cifs]
[akpm@linux-foundation.org: fix smack]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 027e109..7ce0786 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1384,11 +1384,11 @@
 struct dentry *
 nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
-	struct dentry *parent;
 	struct path path = {
-		.mnt = nd->mnt,
+		.mnt = nd->path.mnt,
 		.dentry = dentry,
 	};
+	struct dentry *parent;
 	struct iattr attr;
 	struct rpc_cred *cred;
 	struct nfs4_state *state;
@@ -1433,7 +1433,7 @@
 nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags, struct nameidata *nd)
 {
 	struct path path = {
-		.mnt = nd->mnt,
+		.mnt = nd->path.mnt,
 		.dentry = dentry,
 	};
 	struct rpc_cred *cred;
@@ -1885,7 +1885,7 @@
                  int flags, struct nameidata *nd)
 {
 	struct path path = {
-		.mnt = nd->mnt,
+		.mnt = nd->path.mnt,
 		.dentry = dentry,
 	};
 	struct nfs4_state *state;