kernfs: Add support for always empty directories.
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.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 71ecdab..29d1896 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -45,6 +45,7 @@
KERNFS_LOCKDEP = 0x0100,
KERNFS_SUICIDAL = 0x0400,
KERNFS_SUICIDED = 0x0800,
+ KERNFS_EMPTY_DIR = 0x1000,
};
/* @flags for kernfs_create_root() */
@@ -285,6 +286,8 @@
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,