From 80c298105bf80e33ae494eaeba51f00352b5373c Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Wed, 13 May 2015 16:09:29 -0500
Subject: kernfs: Add support for always empty directories.

commit ea015218f2f7ace2dad9cedd21ed95bdba2886d7 upstream.

Add a new function kernfs_create_empty_dir that can be used to create
directory that can not be modified.

Update the code to use make_empty_dir_inode when reporting a
permanently empty directory to the vfs.

Update the code to not allow adding to permanently empty directories.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/kernfs.h | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'include')

diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 71ecdab1671b..29d1896c3ba5 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -45,6 +45,7 @@ enum kernfs_node_flag {
 	KERNFS_LOCKDEP		= 0x0100,
 	KERNFS_SUICIDAL		= 0x0400,
 	KERNFS_SUICIDED		= 0x0800,
+	KERNFS_EMPTY_DIR	= 0x1000,
 };
 
 /* @flags for kernfs_create_root() */
@@ -285,6 +286,8 @@ void kernfs_destroy_root(struct kernfs_root *root);
 struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
 					 const char *name, umode_t mode,
 					 void *priv, const void *ns);
+struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent,
+					    const char *name);
 struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
 					 const char *name,
 					 umode_t mode, loff_t size,
-- 
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