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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 | /* SPDX-License-Identifier: GPL-2.0-only */ /* * * Copyright (C) 2011 Novell Inc. * Copyright (C) 2016 Red Hat, Inc. */ struct ovl_config { char *lowerdir; char *upperdir; char *workdir; bool default_permissions; bool redirect_dir; bool redirect_follow; const char *redirect_mode; bool index; bool uuid; bool nfs_export; int xino; bool metacopy; bool userxattr; bool ovl_volatile; }; struct ovl_sb { struct super_block *sb; dev_t pseudo_dev; /* Unusable (conflicting) uuid */ bool bad_uuid; /* Used as a lower layer (but maybe also as upper) */ bool is_lower; }; struct ovl_layer { /* ovl_free_fs() relies on @mnt being the first member! */ struct vfsmount *mnt; /* Trap in ovl inode cache */ struct inode *trap; struct ovl_sb *fs; /* Index of this layer in fs root (upper idx == 0) */ int idx; /* One fsid per unique underlying sb (upper fsid == 0) */ int fsid; }; /* * ovl_free_fs() relies on @mnt being the first member when unmounting * the private mounts created for each layer. Let's check both the * offset and type. */ static_assert(offsetof(struct ovl_layer, mnt) == 0); static_assert(__same_type(typeof_member(struct ovl_layer, mnt), struct vfsmount *)); struct ovl_path { const struct ovl_layer *layer; struct dentry *dentry; }; /* private information held for overlayfs's superblock */ struct ovl_fs { unsigned int numlayer; /* Number of unique fs among layers including upper fs */ unsigned int numfs; const struct ovl_layer *layers; struct ovl_sb *fs; /* workbasedir is the path at workdir= mount option */ struct dentry *workbasedir; /* workdir is the 'work' directory under workbasedir */ struct dentry *workdir; /* index directory listing overlay inodes by origin file handle */ struct dentry *indexdir; long namelen; /* pathnames of lower and upper dirs, for show_options */ struct ovl_config config; /* creds of process who forced instantiation of super block */ const struct cred *creator_cred; bool tmpfile; bool noxattr; /* Did we take the inuse lock? */ bool upperdir_locked; bool workdir_locked; bool share_whiteout; /* Traps in ovl inode cache */ struct inode *workbasedir_trap; struct inode *workdir_trap; struct inode *indexdir_trap; /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */ int xino_mode; /* For allocation of non-persistent inode numbers */ atomic_long_t last_ino; /* Whiteout dentry cache */ struct dentry *whiteout; /* r/o snapshot of upperdir sb's only taken on volatile mounts */ errseq_t errseq; }; static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs) { return ofs->layers[0].mnt; } static inline struct ovl_fs *OVL_FS(struct super_block *sb) { return (struct ovl_fs *)sb->s_fs_info; } static inline bool ovl_should_sync(struct ovl_fs *ofs) { return !ofs->config.ovl_volatile; } /* private information held for every overlayfs dentry */ struct ovl_entry { union { struct { unsigned long flags; }; struct rcu_head rcu; }; unsigned numlower; struct ovl_path lowerstack[]; }; struct ovl_entry *ovl_alloc_entry(unsigned int numlower); static inline struct ovl_entry *OVL_E(struct dentry *dentry) { return (struct ovl_entry *) dentry->d_fsdata; } struct ovl_inode { union { struct ovl_dir_cache *cache; /* directory */ struct inode *lowerdata; /* regular file */ }; const char *redirect; u64 version; unsigned long flags; struct inode vfs_inode; struct dentry *__upperdentry; struct ovl_path lowerpath; /* synchronize copy up and more */ struct mutex lock; }; static inline struct ovl_inode *OVL_I(struct inode *inode) { return container_of(inode, struct ovl_inode, vfs_inode); } static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi) { return READ_ONCE(oi->__upperdentry); } |