switch 9p

here we actually *want* ->d_op for root; setting it allows to get rid
of kludge in v9fs_kill_super() since now we have proper ->d_release()
for root and don't need to call it manually.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index c55c614..dbaabe3 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -141,6 +141,11 @@
 	}
 	v9fs_fill_super(sb, v9ses, flags, data);
 
+	if (v9ses->cache)
+		sb->s_d_op = &v9fs_cached_dentry_operations;
+	else
+		sb->s_d_op = &v9fs_dentry_operations;
+
 	inode = v9fs_get_inode(sb, S_IFDIR | mode);
 	if (IS_ERR(inode)) {
 		retval = PTR_ERR(inode);
@@ -217,9 +222,6 @@
 
 	P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);
 
-	if (s->s_root)
-		v9fs_dentry_release(s->s_root);	/* clunk root */
-
 	kill_anon_super(s);
 
 	v9fs_session_cancel(v9ses);