SUNRPC: Clean up the sillyrename code

Fix a couple of bugs:
 - Don't rely on the parent dentry still being valid when the call completes.
   Fixes a race with shrink_dcache_for_umount_subtree()

 - Don't remove the file if the filehandle has been labelled as stale.

Fix a couple of inefficiencies
 - Remove the global list of sillyrenamed files. Instead we can cache the
   sillyrename information in the dentry->d_fsdata
 - Move common code from unlink_setup/unlink_done into fs/nfs/unlink.c

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 7babcb1..cf74a4d 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -791,9 +791,8 @@
 	int	(*create)  (struct inode *, struct dentry *,
 			    struct iattr *, int, struct nameidata *);
 	int	(*remove)  (struct inode *, struct qstr *);
-	int	(*unlink_setup)  (struct rpc_message *,
-			    struct dentry *, struct qstr *);
-	int	(*unlink_done) (struct dentry *, struct rpc_task *);
+	void	(*unlink_setup)  (struct rpc_message *, struct inode *dir);
+	int	(*unlink_done) (struct rpc_task *, struct inode *);
 	int	(*rename)  (struct inode *, struct qstr *,
 			    struct inode *, struct qstr *);
 	int	(*link)    (struct inode *, struct inode *, struct qstr *);