fs/overlayfs/ovl_entry.h

   1 /*
   2  *
   3  * Copyright (C) 2011 Novell Inc.
   4  * Copyright (C) 2016 Red Hat, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10
  11 struct ovl_config {
  12         char *lowerdir;
  13         char *upperdir;
  14         char *workdir;
  15         bool default_permissions;
  16         bool redirect_dir;
  17 };
  18
  19 /* private information held for overlayfs's superblock */
  20 struct ovl_fs {
  21         struct vfsmount *upper_mnt;
  22         unsigned numlower;
  23         struct vfsmount **lower_mnt;
  24         struct dentry *workdir;
  25         long namelen;
  26         /* pathnames of lower and upper dirs, for show_options */
  27         struct ovl_config config;
  28         /* creds of process who forced instantiation of super block */
  29         const struct cred *creator_cred;
  30 };
  31
  32 /* private information held for every overlayfs dentry */
  33 struct ovl_entry {
  34         struct dentry *__upperdentry;
  35         struct ovl_dir_cache *cache;
  36         union {
  37                 struct {
  38                         u64 version;
  39                         const char *redirect;
  40                         bool opaque;
  41                 };
  42                 struct rcu_head rcu;
  43         };
  44         unsigned numlower;
  45         struct path lowerstack[];
  46 };
  47
  48 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
  49
  50 static inline struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
  51 {
  52         return lockless_dereference(oe->__upperdentry);
  53 }