1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * 4 * Copyright (C) 2011 Novell Inc. 5 * Copyright (C) 2016 Red Hat, Inc. 6 */ 7 8 struct ovl_config { 9 char *lowerdir; 10 char *upperdir; 11 char *workdir; 12 bool default_permissions; 13 bool redirect_dir; 14 bool redirect_follow; 15 const char *redirect_mode; 16 bool index; 17 bool nfs_export; 18 int xino; 19 bool metacopy; 20 }; 21 22 struct ovl_sb { 23 struct super_block *sb; 24 dev_t pseudo_dev; 25 /* Unusable (conflicting) uuid */ 26 bool bad_uuid; 27 /* Used as a lower layer (but maybe also as upper) */ 28 bool is_lower; 29 }; 30 31 struct ovl_layer { 32 struct vfsmount *mnt; 33 /* Trap in ovl inode cache */ 34 struct inode *trap; 35 struct ovl_sb *fs; 36 /* Index of this layer in fs root (upper idx == 0) */ 37 int idx; 38 /* One fsid per unique underlying sb (upper fsid == 0) */ 39 int fsid; 40 }; 41 42 struct ovl_path { 43 const struct ovl_layer *layer; 44 struct dentry *dentry; 45 }; 46 47 /* private information held for overlayfs's superblock */ 48 struct ovl_fs { 49 unsigned int numlayer; 50 /* Number of unique fs among layers including upper fs */ 51 unsigned int numfs; 52 const struct ovl_layer *layers; 53 struct ovl_sb *fs; 54 /* workbasedir is the path at workdir= mount option */ 55 struct dentry *workbasedir; 56 /* workdir is the 'work' directory under workbasedir */ 57 struct dentry *workdir; 58 /* index directory listing overlay inodes by origin file handle */ 59 struct dentry *indexdir; 60 long namelen; 61 /* pathnames of lower and upper dirs, for show_options */ 62 struct ovl_config config; 63 /* creds of process who forced instantiation of super block */ 64 const struct cred *creator_cred; 65 bool tmpfile; 66 bool noxattr; 67 /* Did we take the inuse lock? */ 68 bool upperdir_locked; 69 bool workdir_locked; 70 bool share_whiteout; 71 /* Traps in ovl inode cache */ 72 struct inode *workbasedir_trap; 73 struct inode *workdir_trap; 74 struct inode *indexdir_trap; 75 /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */ 76 int xino_mode; 77 /* For allocation of non-persistent inode numbers */ 78 atomic_long_t last_ino; 79 /* Whiteout dentry cache */ 80 struct dentry *whiteout; 81 }; 82 83 static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs) 84 { 85 return ofs->layers[0].mnt; 86 } 87 88 static inline struct ovl_fs *OVL_FS(struct super_block *sb) 89 { 90 return (struct ovl_fs *)sb->s_fs_info; 91 } 92 93 /* private information held for every overlayfs dentry */ 94 struct ovl_entry { 95 union { 96 struct { 97 unsigned long flags; 98 }; 99 struct rcu_head rcu; 100 }; 101 unsigned numlower; 102 struct ovl_path lowerstack[]; 103 }; 104 105 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 106 107 static inline struct ovl_entry *OVL_E(struct dentry *dentry) 108 { 109 return (struct ovl_entry *) dentry->d_fsdata; 110 } 111 112 struct ovl_inode { 113 union { 114 struct ovl_dir_cache *cache; /* directory */ 115 struct inode *lowerdata; /* regular file */ 116 }; 117 const char *redirect; 118 u64 version; 119 unsigned long flags; 120 struct inode vfs_inode; 121 struct dentry *__upperdentry; 122 struct inode *lower; 123 124 /* synchronize copy up and more */ 125 struct mutex lock; 126 }; 127 128 static inline struct ovl_inode *OVL_I(struct inode *inode) 129 { 130 return container_of(inode, struct ovl_inode, vfs_inode); 131 } 132 133 static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi) 134 { 135 return READ_ONCE(oi->__upperdentry); 136 } 137