1 files changed, 26 insertions, 6 deletions

diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index b0122dc6f96a..52bf5677db0b 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -50,7 +50,24 @@ enum kernfs_node_flag {
 
 /* @flags for kernfs_create_root() */
 enum kernfs_root_flag {
-        KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
+        /*
+         * kernfs_nodes are created in the deactivated state and invisible.
+         * They require explicit kernfs_activate() to become visible.  This
+         * can be used to make related nodes become visible atomically
+         * after all nodes are created successfully.
+         */
+        KERNFS_ROOT_CREATE_DEACTIVATED          = 0x0001,
+
+        /*
+         * For regular flies, if the opener has CAP_DAC_OVERRIDE, open(2)
+         * succeeds regardless of the RW permissions.  sysfs had an extra
+         * layer of enforcement where open(2) fails with -EACCES regardless
+         * of CAP_DAC_OVERRIDE if the permission doesn't have the
+         * respective read or write access at all (none of S_IRUGO or
+         * S_IWUGO) or the respective operation isn't implemented.  The
+         * following flag enables that behavior.
+         */
+        KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK       = 0x0002,
 };
 
 /* type-specific structures for kernfs_node union members */
@@ -280,8 +297,8 @@ void kernfs_notify(struct kernfs_node *kn);
 
 const void *kernfs_super_ns(struct super_block *sb);
 struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
-                               struct kernfs_root *root, bool *new_sb_created,
-                               const void *ns);
+                               struct kernfs_root *root, unsigned long magic,
+                               bool *new_sb_created, const void *ns);
 void kernfs_kill_sb(struct super_block *sb);
 
 void kernfs_init(void);
@@ -374,7 +391,8 @@ static inline const void *kernfs_super_ns(struct super_block *sb)
 
 static inline struct dentry *
 kernfs_mount_ns(struct file_system_type *fs_type, int flags,
-                struct kernfs_root *root, bool *new_sb_created, const void *ns)
+                struct kernfs_root *root, unsigned long magic,
+                bool *new_sb_created, const void *ns)
 { return ERR_PTR(-ENOSYS); }
 
 static inline void kernfs_kill_sb(struct super_block *sb) { }
@@ -432,9 +450,11 @@ static inline int kernfs_rename(struct kernfs_node *kn,
 
 static inline struct dentry *
 kernfs_mount(struct file_system_type *fs_type, int flags,
-             struct kernfs_root *root, bool *new_sb_created)
+                struct kernfs_root *root, unsigned long magic,
+                bool *new_sb_created)
 {
-        return kernfs_mount_ns(fs_type, flags, root, new_sb_created, NULL);
+        return kernfs_mount_ns(fs_type, flags, root,
+                                magic, new_sb_created, NULL);
 }
 
 #endif  /* __LINUX_KERNFS_H */