new helper: ihold()

Clones an existing reference to inode; caller must already hold one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 0d38c09..5439e1b 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1045,7 +1045,7 @@
 	if (ret < 0)
 		goto link_error;
 
-	atomic_inc(&vnode->vfs_inode.i_count);
+	ihold(&vnode->vfs_inode);
 	d_instantiate(dentry, &vnode->vfs_inode);
 	key_put(key);
 	_leave(" = 0");