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 redirect_follow;
  18         const char *redirect_mode;
  19         bool index;
  20 };
  21
  22 struct ovl_layer {
  23         struct vfsmount *mnt;
  24         dev_t pseudo_dev;
  25 };
  26
  27 struct ovl_path {
  28         struct ovl_layer *layer;
  29         struct dentry *dentry;
  30 };
  31
  32 /* private information held for overlayfs's superblock */
  33 struct ovl_fs {
  34         struct vfsmount *upper_mnt;
  35         unsigned numlower;
  36         struct ovl_layer *lower_layers;
  37         /* workbasedir is the path at workdir= mount option */
  38         struct dentry *workbasedir;
  39         /* workdir is the 'work' directory under workbasedir */
  40         struct dentry *workdir;
  41         /* index directory listing overlay inodes by origin file handle */
  42         struct dentry *indexdir;
  43         long namelen;
  44         /* pathnames of lower and upper dirs, for show_options */
  45         struct ovl_config config;
  46         /* creds of process who forced instantiation of super block */
  47         const struct cred *creator_cred;
  48         bool tmpfile;
  49         bool noxattr;
  50         /* sb common to all layers */
  51         struct super_block *same_sb;
  52         /* Did we take the inuse lock? */
  53         bool upperdir_locked;
  54         bool workdir_locked;
  55 };
  56
  57 /* private information held for every overlayfs dentry */
  58 struct ovl_entry {
  59         union {
  60                 struct {
  61                         unsigned long has_upper;
  62                         bool opaque;
  63                 };
  64                 struct rcu_head rcu;
  65         };
  66         unsigned numlower;
  67         struct ovl_path lowerstack[];
  68 };
  69
  70 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
  71
  72 struct ovl_inode {
  73         struct ovl_dir_cache *cache;
  74         const char *redirect;
  75         u64 version;
  76         unsigned long flags;
  77         struct inode vfs_inode;
  78         struct dentry *__upperdentry;
  79         struct inode *lower;
  80
  81         /* synchronize copy up and more */
  82         struct mutex lock;
  83 };
  84
  85 static inline struct ovl_inode *OVL_I(struct inode *inode)
  86 {
  87         return container_of(inode, struct ovl_inode, vfs_inode);
  88 }
  89
  90 static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
  91 {
  92         return READ_ONCE(oi->__upperdentry);
  93 }