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 override_creds; 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 }; 29 30 struct ovl_layer { 31 /* ovl_free_fs() relies on @mnt being the first member! */ 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 /* 43 * ovl_free_fs() relies on @mnt being the first member when unmounting 44 * the private mounts created for each layer. Let's check both the 45 * offset and type. 46 */ 47 static_assert(offsetof(struct ovl_layer, mnt) == 0); 48 static_assert(__same_type(typeof_member(struct ovl_layer, mnt), struct vfsmount *)); 49 50 struct ovl_path { 51 struct ovl_layer *layer; 52 struct dentry *dentry; 53 }; 54 55 /* private information held for overlayfs's superblock */ 56 struct ovl_fs { 57 struct vfsmount *upper_mnt; 58 unsigned int numlower; 59 /* Number of unique lower sb that differ from upper sb */ 60 unsigned int numlowerfs; 61 struct ovl_layer *lower_layers; 62 struct ovl_sb *lower_fs; 63 /* workbasedir is the path at workdir= mount option */ 64 struct dentry *workbasedir; 65 /* workdir is the 'work' directory under workbasedir */ 66 struct dentry *workdir; 67 /* index directory listing overlay inodes by origin file handle */ 68 struct dentry *indexdir; 69 long namelen; 70 /* pathnames of lower and upper dirs, for show_options */ 71 struct ovl_config config; 72 /* creds of process who forced instantiation of super block */ 73 const struct cred *creator_cred; 74 bool tmpfile; 75 bool noxattr; 76 /* Did we take the inuse lock? */ 77 bool upperdir_locked; 78 bool workdir_locked; 79 /* Traps in ovl inode cache */ 80 struct inode *upperdir_trap; 81 struct inode *workbasedir_trap; 82 struct inode *workdir_trap; 83 struct inode *indexdir_trap; 84 /* Inode numbers in all layers do not use the high xino_bits */ 85 unsigned int xino_bits; 86 }; 87 88 /* private information held for every overlayfs dentry */ 89 struct ovl_entry { 90 union { 91 struct { 92 unsigned long flags; 93 }; 94 struct rcu_head rcu; 95 }; 96 unsigned numlower; 97 struct ovl_path lowerstack[]; 98 }; 99 100 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 101 OVL_E(struct dentry * dentry)102static inline struct ovl_entry *OVL_E(struct dentry *dentry) 103 { 104 return (struct ovl_entry *) dentry->d_fsdata; 105 } 106 107 struct ovl_inode { 108 union { 109 struct ovl_dir_cache *cache; /* directory */ 110 struct inode *lowerdata; /* regular file */ 111 }; 112 const char *redirect; 113 u64 version; 114 unsigned long flags; 115 struct inode vfs_inode; 116 struct dentry *__upperdentry; 117 struct inode *lower; 118 119 /* synchronize copy up and more */ 120 struct mutex lock; 121 }; 122 OVL_I(struct inode * inode)123static inline struct ovl_inode *OVL_I(struct inode *inode) 124 { 125 return container_of(inode, struct ovl_inode, vfs_inode); 126 } 127 ovl_upperdentry_dereference(struct ovl_inode * oi)128static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi) 129 { 130 return READ_ONCE(oi->__upperdentry); 131 } 132