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 /* ovl_free_fs() relies on @mnt being the first member! */ 34 struct vfsmount *mnt; 35 /* Trap in ovl inode cache */ 36 struct inode *trap; 37 struct ovl_sb *fs; 38 /* Index of this layer in fs root (upper idx == 0) */ 39 int idx; 40 /* One fsid per unique underlying sb (upper fsid == 0) */ 41 int fsid; 42 }; 43 44 /* 45 * ovl_free_fs() relies on @mnt being the first member when unmounting 46 * the private mounts created for each layer. Let's check both the 47 * offset and type. 48 */ 49 static_assert(offsetof(struct ovl_layer, mnt) == 0); 50 static_assert(__same_type(typeof_member(struct ovl_layer, mnt), struct vfsmount *)); 51 52 struct ovl_path { 53 const struct ovl_layer *layer; 54 struct dentry *dentry; 55 }; 56 57 /* private information held for overlayfs's superblock */ 58 struct ovl_fs { 59 unsigned int numlayer; 60 /* Number of unique fs among layers including upper fs */ 61 unsigned int numfs; 62 const struct ovl_layer *layers; 63 struct ovl_sb *fs; 64 /* workbasedir is the path at workdir= mount option */ 65 struct dentry *workbasedir; 66 /* workdir is the 'work' directory under workbasedir */ 67 struct dentry *workdir; 68 /* index directory listing overlay inodes by origin file handle */ 69 struct dentry *indexdir; 70 long namelen; 71 /* pathnames of lower and upper dirs, for show_options */ 72 struct ovl_config config; 73 /* creds of process who forced instantiation of super block */ 74 const struct cred *creator_cred; 75 bool tmpfile; 76 bool noxattr; 77 /* Did we take the inuse lock? */ 78 bool upperdir_locked; 79 bool workdir_locked; 80 bool share_whiteout; 81 /* Traps in ovl inode cache */ 82 struct inode *workbasedir_trap; 83 struct inode *workdir_trap; 84 struct inode *indexdir_trap; 85 /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */ 86 int xino_mode; 87 /* For allocation of non-persistent inode numbers */ 88 atomic_long_t last_ino; 89 /* Whiteout dentry cache */ 90 struct dentry *whiteout; 91 /* r/o snapshot of upperdir sb's only taken on volatile mounts */ 92 errseq_t errseq; 93 }; 94 ovl_upper_mnt(struct ovl_fs * ofs)95static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs) 96 { 97 return ofs->layers[0].mnt; 98 } 99 OVL_FS(struct super_block * sb)100static inline struct ovl_fs *OVL_FS(struct super_block *sb) 101 { 102 return (struct ovl_fs *)sb->s_fs_info; 103 } 104 ovl_should_sync(struct ovl_fs * ofs)105static inline bool ovl_should_sync(struct ovl_fs *ofs) 106 { 107 return !ofs->config.ovl_volatile; 108 } 109 110 /* private information held for every overlayfs dentry */ 111 struct ovl_entry { 112 union { 113 struct { 114 unsigned long flags; 115 }; 116 struct rcu_head rcu; 117 }; 118 unsigned numlower; 119 struct ovl_path lowerstack[]; 120 }; 121 122 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 123 OVL_E(struct dentry * dentry)124static inline struct ovl_entry *OVL_E(struct dentry *dentry) 125 { 126 return (struct ovl_entry *) dentry->d_fsdata; 127 } 128 129 struct ovl_inode { 130 union { 131 struct ovl_dir_cache *cache; /* directory */ 132 struct inode *lowerdata; /* regular file */ 133 }; 134 const char *redirect; 135 u64 version; 136 unsigned long flags; 137 struct inode vfs_inode; 138 struct dentry *__upperdentry; 139 struct inode *lower; 140 141 /* synchronize copy up and more */ 142 struct mutex lock; 143 }; 144 OVL_I(struct inode * inode)145static inline struct ovl_inode *OVL_I(struct inode *inode) 146 { 147 return container_of(inode, struct ovl_inode, vfs_inode); 148 } 149 ovl_upperdentry_dereference(struct ovl_inode * oi)150static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi) 151 { 152 return READ_ONCE(oi->__upperdentry); 153 } 154