+enum kernfs_node_type {
+ KERNFS_DIR = 0x0001,
+ KERNFS_FILE = 0x0002,
+ KERNFS_LINK = 0x0004,
+};
+
+#define KERNFS_TYPE_MASK 0x000f
+#define KERNFS_COPY_NAME (KERNFS_DIR | KERNFS_LINK)
+#define KERNFS_ACTIVE_REF KERNFS_FILE
+#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK
+
+enum kernfs_node_flag {
+ KERNFS_REMOVED = 0x0010,
+ KERNFS_NS = 0x0020,
+ KERNFS_HAS_SEQ_SHOW = 0x0040,
+ KERNFS_HAS_MMAP = 0x0080,
+ KERNFS_LOCKDEP = 0x0100,
+};
+
+/* type-specific structures for kernfs_node union members */
+struct kernfs_elem_dir {
+ unsigned long subdirs;
+ /* children rbtree starts here and goes through kn->rb */
+ struct rb_root children;
+
+ /*
+ * The kernfs hierarchy this directory belongs to. This fits
+ * better directly in kernfs_node but is here to save space.
+ */
+ struct kernfs_root *root;
+};
+
+struct kernfs_elem_symlink {
+ struct kernfs_node *target_kn;
+};
+
+struct kernfs_elem_attr {
+ const struct kernfs_ops *ops;
+ struct kernfs_open_node *open;
+ loff_t size;
+};
+
+/*
+ * kernfs_node - the building block of kernfs hierarchy. Each and every
+ * kernfs node is represented by single kernfs_node. Most fields are
+ * private to kernfs and shouldn't be accessed directly by kernfs users.
+ *
+ * As long as s_count reference is held, the kernfs_node itself is
+ * accessible. Dereferencing elem or any other outer entity requires
+ * active reference.
+ */
+struct kernfs_node {
+ atomic_t count;
+ atomic_t active;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
+ /* the following two fields are published */
+ struct kernfs_node *parent;
+ const char *name;
+
+ struct rb_node rb;
+
+ union {
+ struct completion *completion;
+ struct kernfs_node *removed_list;
+ } u;
+
+ const void *ns; /* namespace tag */
+ unsigned int hash; /* ns + name hash */
+ union {
+ struct kernfs_elem_dir dir;
+ struct kernfs_elem_symlink symlink;
+ struct kernfs_elem_attr attr;
+ };
+
+ void *priv;
+
+ unsigned short flags;
+ umode_t mode;
+ unsigned int ino;
+ struct kernfs_iattrs *iattr;
+};
+
+struct kernfs_root {
+ /* published fields */
+ struct kernfs_node *kn;
+
+ /* private fields, do not use outside kernfs proper */
+ struct ida ino_ida;
+};
+
+struct kernfs_open_file {