6 files changed, 41 insertions, 4 deletions

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 2f117c57160d..3dcf0b8b4e93 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -450,6 +450,11 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
  *
  * If debugfs is not enabled in the kernel, the value -%ENODEV will be
  * returned.
+ *
+ * NOTE: it's expected that most callers should _ignore_ the errors returned
+ * by this function. Other debugfs functions handle the fact that the "dentry"
+ * passed to them could be an error and they don't crash in that case.
+ * Drivers should generally work fine even if debugfs fails to init anyway.
  */
 struct dentry *debugfs_create_file(const char *name, umode_t mode,
 				   struct dentry *parent, void *data,
@@ -551,6 +556,11 @@ EXPORT_SYMBOL_GPL(debugfs_create_file_size);
  *
  * If debugfs is not enabled in the kernel, the value -%ENODEV will be
  * returned.
+ *
+ * NOTE: it's expected that most callers should _ignore_ the errors returned
+ * by this function. Other debugfs functions handle the fact that the "dentry"
+ * passed to them could be an error and they don't crash in that case.
+ * Drivers should generally work fine even if debugfs fails to init anyway.
  */
 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 {
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index e6d9772ddb4c..61a8edc4ba8b 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -971,6 +971,15 @@ void kernfs_destroy_root(struct kernfs_root *root)
 }
 
 /**
+ * kernfs_root_to_node - return the kernfs_node associated with a kernfs_root
+ * @root: root to use to lookup
+ */
+struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root)
+{
+	return root->kn;
+}
+
+/**
  * kernfs_create_dir_ns - create a directory
  * @parent: parent in which to create a new directory
  * @name: name of the new directory
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index 9414a7a60a9f..74067a73ff78 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -1002,7 +1002,7 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
 #endif
 
 	/*
-	 * kn->attr.ops is accesible only while holding active ref.  We
+	 * kn->attr.ops is accessible only while holding active ref.  We
 	 * need to know whether some ops are implemented outside active
 	 * ref.  Cache their existence in flags.
 	 */
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index f9cc912c31e1..eeaa779b929c 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -31,6 +31,24 @@ struct kernfs_iattrs {
 	atomic_t		user_xattr_size;
 };
 
+struct kernfs_root {
+	/* published fields */
+	struct kernfs_node	*kn;
+	unsigned int		flags;	/* KERNFS_ROOT_* flags */
+
+	/* private fields, do not use outside kernfs proper */
+	struct idr		ino_idr;
+	u32			last_id_lowbits;
+	u32			id_highbits;
+	struct kernfs_syscall_ops *syscall_ops;
+
+	/* list of kernfs_super_info of this root, protected by kernfs_rwsem */
+	struct list_head	supers;
+
+	wait_queue_head_t	deactivate_waitq;
+	struct rw_semaphore	kernfs_rwsem;
+};
+
 /* +1 to avoid triggering overflow warning when negating it */
 #define KN_DEACTIVATED_BIAS		(INT_MIN + 1)
 
@@ -122,7 +140,6 @@ int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
 /*
  * dir.c
  */
-extern struct rw_semaphore kernfs_rwsem;
 extern const struct dentry_operations kernfs_dops;
 extern const struct file_operations kernfs_dir_fops;
 extern const struct inode_operations kernfs_dir_iops;
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index e747c135c1d1..98467bb76737 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -103,7 +103,7 @@ int __init sysfs_init(void)
 	if (IS_ERR(sysfs_root))
 		return PTR_ERR(sysfs_root);
 
-	sysfs_root_kn = sysfs_root->kn;
+	sysfs_root_kn = kernfs_root_to_node(sysfs_root);
 
 	err = register_filesystem(&sysfs_fs_type);
 	if (err) {
diff --git a/fs/ubifs/sysfs.c b/fs/ubifs/sysfs.c
index 7acc5a74e5fa..06ad8fa1fcfb 100644
--- a/fs/ubifs/sysfs.c
+++ b/fs/ubifs/sysfs.c
@@ -42,6 +42,7 @@ static struct attribute *ubifs_attrs[] = {
 	ATTR_LIST(errors_crc),
 	NULL,
 };
+ATTRIBUTE_GROUPS(ubifs);
 
 static ssize_t ubifs_attr_show(struct kobject *kobj,
 			       struct attribute *attr, char *buf)
@@ -74,7 +75,7 @@ static const struct sysfs_ops ubifs_attr_ops = {
 };
 
 static struct kobj_type ubifs_sb_ktype = {
-	.default_attrs	= ubifs_attrs,
+	.default_groups	= ubifs_groups,
 	.sysfs_ops	= &ubifs_attr_ops,
 	.release	= ubifs_sb_release,
 };