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 };
  17
  18 /* private information held for overlayfs's superblock */
  19 struct ovl_fs {
  20         struct vfsmount *upper_mnt;
  21         unsigned numlower;
  22         struct vfsmount **lower_mnt;
  23         struct dentry *workdir;
  24         long namelen;
  25         /* pathnames of lower and upper dirs, for show_options */
  26         struct ovl_config config;
  27         /* creds of process who forced instantiation of super block */
  28         const struct cred *creator_cred;
  29 };
  30
  31 /* private information held for every overlayfs dentry */
  32 struct ovl_entry {
  33         struct dentry *__upperdentry;
  34         struct ovl_dir_cache *cache;
  35         union {
  36                 struct {
  37                         u64 version;
  38                         bool opaque;
  39                 };
  40                 struct rcu_head rcu;
  41         };
  42         unsigned numlower;
  43         struct path lowerstack[];
  44 };
  45
  46 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
  47
  48 static inline struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
  49 {
  50         return lockless_dereference(oe->__upperdentry);
  51 }