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         bool index;
  18 };
  19
  20 /* private information held for overlayfs's superblock */
  21 struct ovl_fs {
  22         struct vfsmount *upper_mnt;
  23         unsigned numlower;
  24         struct vfsmount **lower_mnt;
  25         /* workbasedir is the path at workdir= mount option */
  26         struct dentry *workbasedir;
  27         /* workdir is the 'work' directory under workbasedir */
  28         struct dentry *workdir;
  29         /* index directory listing overlay inodes by origin file handle */
  30         struct dentry *indexdir;
  31         long namelen;
  32         /* pathnames of lower and upper dirs, for show_options */
  33         struct ovl_config config;
  34         /* creds of process who forced instantiation of super block */
  35         const struct cred *creator_cred;
  36         bool tmpfile;
  37         bool noxattr;
  38         /* sb common to all layers */
  39         struct super_block *same_sb;
  40         /* Did we take the inuse lock? */
  41         bool upperdir_locked;
  42         bool workdir_locked;
  43 };
  44
  45 /* private information held for every overlayfs dentry */
  46 struct ovl_entry {
  47         union {
  48                 struct {
  49                         unsigned long has_upper;
  50                         bool opaque;
  51                 };
  52                 struct rcu_head rcu;
  53         };
  54         unsigned numlower;
  55         struct path lowerstack[];
  56 };
  57
  58 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
  59
  60 struct ovl_inode {
  61         struct ovl_dir_cache *cache;
  62         const char *redirect;
  63         u64 version;
  64         unsigned long flags;
  65         struct inode vfs_inode;
  66         struct dentry *__upperdentry;
  67         struct inode *lower;
  68
  69         /* synchronize copy up and more */
  70         struct mutex lock;
  71 };
  72
  73 static inline struct ovl_inode *OVL_I(struct inode *inode)
  74 {
  75         return container_of(inode, struct ovl_inode, vfs_inode);
  76 }
  77
  78 static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
  79 {
  80         return lockless_dereference(oi->__upperdentry);
  81 }