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 bool ovl_volatile; 21 }; 22 23 struct ovl_sb { 24 struct super_block *sb; 25 dev_t pseudo_dev; 26 /* Unusable (conflicting) uuid */ 27 bool bad_uuid; 28 /* Used as a lower layer (but maybe also as upper) */ 29 bool is_lower; 30 }; 31 32 struct ovl_layer { 33 struct vfsmount *mnt; 34 /* Trap in ovl inode cache */ 35 struct inode *trap; 36 struct ovl_sb *fs; 37 /* Index of this layer in fs root (upper idx == 0) */ 38 int idx; 39 /* One fsid per unique underlying sb (upper fsid == 0) */ 40 int fsid; 41 }; 42 43 struct ovl_path { 44 const struct ovl_layer *layer; 45 struct dentry *dentry; 46 }; 47 48 /* private information held for overlayfs's superblock */ 49 struct ovl_fs { 50 unsigned int numlayer; 51 /* Number of unique fs among layers including upper fs */ 52 unsigned int numfs; 53 const struct ovl_layer *layers; 54 struct ovl_sb *fs; 55 /* workbasedir is the path at workdir= mount option */ 56 struct dentry *workbasedir; 57 /* workdir is the 'work' directory under workbasedir */ 58 struct dentry *workdir; 59 /* index directory listing overlay inodes by origin file handle */ 60 struct dentry *indexdir; 61 long namelen; 62 /* pathnames of lower and upper dirs, for show_options */ 63 struct ovl_config config; 64 /* creds of process who forced instantiation of super block */ 65 const struct cred *creator_cred; 66 bool tmpfile; 67 bool noxattr; 68 /* Did we take the inuse lock? */ 69 bool upperdir_locked; 70 bool workdir_locked; 71 bool share_whiteout; 72 /* Traps in ovl inode cache */ 73 struct inode *workbasedir_trap; 74 struct inode *workdir_trap; 75 struct inode *indexdir_trap; 76 /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */ 77 int xino_mode; 78 /* For allocation of non-persistent inode numbers */ 79 atomic_long_t last_ino; 80 /* Whiteout dentry cache */ 81 struct dentry *whiteout; 82 /* r/o snapshot of upperdir sb's only taken on volatile mounts */ 83 errseq_t errseq; 84 }; 85 ovl_upper_mnt(struct ovl_fs * ofs)86static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs) 87 { 88 return ofs->layers[0].mnt; 89 } 90 OVL_FS(struct super_block * sb)91static inline struct ovl_fs *OVL_FS(struct super_block *sb) 92 { 93 return (struct ovl_fs *)sb->s_fs_info; 94 } 95 ovl_should_sync(struct ovl_fs * ofs)96static inline bool ovl_should_sync(struct ovl_fs *ofs) 97 { 98 return !ofs->config.ovl_volatile; 99 } 100 101 /* private information held for every overlayfs dentry */ 102 struct ovl_entry { 103 union { 104 struct { 105 unsigned long flags; 106 }; 107 struct rcu_head rcu; 108 }; 109 unsigned numlower; 110 struct ovl_path lowerstack[]; 111 }; 112 113 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 114 OVL_E(struct dentry * dentry)115static inline struct ovl_entry *OVL_E(struct dentry *dentry) 116 { 117 return (struct ovl_entry *) dentry->d_fsdata; 118 } 119 120 struct ovl_inode { 121 union { 122 struct ovl_dir_cache *cache; /* directory */ 123 struct inode *lowerdata; /* regular file */ 124 }; 125 const char *redirect; 126 u64 version; 127 unsigned long flags; 128 struct inode vfs_inode; 129 struct dentry *__upperdentry; 130 struct inode *lower; 131 132 /* synchronize copy up and more */ 133 struct mutex lock; 134 }; 135 OVL_I(struct inode * inode)136static inline struct ovl_inode *OVL_I(struct inode *inode) 137 { 138 return container_of(inode, struct ovl_inode, vfs_inode); 139 } 140 ovl_upperdentry_dereference(struct ovl_inode * oi)141static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi) 142 { 143 return READ_ONCE(oi->__upperdentry); 144 } 145