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 READ_ONCE(oi->__upperdentry); 81 } 82