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         bool tmpfile;
  31         bool noxattr;
  32         /* sb common to all layers */
  33         struct super_block *same_sb;
  34 };
  35
  36 /* private information held for every overlayfs dentry */
  37 struct ovl_entry {
  38         struct ovl_dir_cache *cache;
  39         union {
  40                 struct {
  41                         u64 version;
  42                         bool opaque;
  43                 };
  44                 struct rcu_head rcu;
  45         };
  46         unsigned numlower;
  47         struct path lowerstack[];
  48 };
  49
  50 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
  51
  52 struct ovl_inode {
  53         const char *redirect;
  54         unsigned long flags;
  55         struct inode vfs_inode;
  56         struct dentry *__upperdentry;
  57         struct inode *lower;
  58
  59         /* synchronize copy up and more */
  60         struct mutex lock;
  61 };
  62
  63 static inline struct ovl_inode *OVL_I(struct inode *inode)
  64 {
  65         return container_of(inode, struct ovl_inode, vfs_inode);
  66 }
  67
  68 static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
  69 {
  70         return lockless_dereference(oi->__upperdentry);
  71 }