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/xattr.c b/fs/xattr.c
index f7c8f87..be0ee75 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -262,7 +262,7 @@
 	error = user_path_walk(path, &nd);
 	if (error)
 		return error;
-	error = setxattr(nd.dentry, name, value, size, flags);
+	error = setxattr(nd.path.dentry, name, value, size, flags);
 	path_release(&nd);
 	return error;
 }
@@ -277,7 +277,7 @@
 	error = user_path_walk_link(path, &nd);
 	if (error)
 		return error;
-	error = setxattr(nd.dentry, name, value, size, flags);
+	error = setxattr(nd.path.dentry, name, value, size, flags);
 	path_release(&nd);
 	return error;
 }
@@ -347,7 +347,7 @@
 	error = user_path_walk(path, &nd);
 	if (error)
 		return error;
-	error = getxattr(nd.dentry, name, value, size);
+	error = getxattr(nd.path.dentry, name, value, size);
 	path_release(&nd);
 	return error;
 }
@@ -362,7 +362,7 @@
 	error = user_path_walk_link(path, &nd);
 	if (error)
 		return error;
-	error = getxattr(nd.dentry, name, value, size);
+	error = getxattr(nd.path.dentry, name, value, size);
 	path_release(&nd);
 	return error;
 }
@@ -421,7 +421,7 @@
 	error = user_path_walk(path, &nd);
 	if (error)
 		return error;
-	error = listxattr(nd.dentry, list, size);
+	error = listxattr(nd.path.dentry, list, size);
 	path_release(&nd);
 	return error;
 }
@@ -435,7 +435,7 @@
 	error = user_path_walk_link(path, &nd);
 	if (error)
 		return error;
-	error = listxattr(nd.dentry, list, size);
+	error = listxattr(nd.path.dentry, list, size);
 	path_release(&nd);
 	return error;
 }
@@ -482,7 +482,7 @@
 	error = user_path_walk(path, &nd);
 	if (error)
 		return error;
-	error = removexattr(nd.dentry, name);
+	error = removexattr(nd.path.dentry, name);
 	path_release(&nd);
 	return error;
 }
@@ -496,7 +496,7 @@
 	error = user_path_walk_link(path, &nd);
 	if (error)
 		return error;
-	error = removexattr(nd.dentry, name);
+	error = removexattr(nd.path.dentry, name);
 	path_release(&nd);
 	return error;
 }