| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Copyright (C) 2011 Novell Inc. |
| 4 | * Copyright (C) 2016 Red Hat, Inc. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify it |
| 7 | * under the terms of the GNU General Public License version 2 as published by |
| 8 | * the Free Software Foundation. |
| 9 | */ |
| 10 | |
| 11 | struct ovl_config { |
| 12 | char *lowerdir; |
| 13 | char *upperdir; |
| 14 | char *workdir; |
| 15 | bool default_permissions; |
| 16 | bool redirect_dir; |
| 17 | bool redirect_follow; |
| 18 | const char *redirect_mode; |
| 19 | bool index; |
| 20 | bool nfs_export; |
| 21 | int xino; |
| 22 | bool metacopy; |
| 23 | bool override_creds; |
| 24 | }; |
| 25 | |
| 26 | struct ovl_sb { |
| 27 | struct super_block *sb; |
| 28 | dev_t pseudo_dev; |
| 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 | struct ovl_layer *layer; |
| 44 | struct dentry *dentry; |
| 45 | }; |
| 46 | |
| 47 | /* private information held for overlayfs's superblock */ |
| 48 | struct ovl_fs { |
| 49 | struct vfsmount *upper_mnt; |
| 50 | unsigned int numlower; |
| 51 | /* Number of unique lower sb that differ from upper sb */ |
| 52 | unsigned int numlowerfs; |
| 53 | struct ovl_layer *lower_layers; |
| 54 | struct ovl_sb *lower_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 | /* Traps in ovl inode cache */ |
| 72 | struct inode *upperdir_trap; |
| 73 | struct inode *workbasedir_trap; |
| 74 | struct inode *workdir_trap; |
| 75 | struct inode *indexdir_trap; |
| 76 | /* Inode numbers in all layers do not use the high xino_bits */ |
| 77 | unsigned int xino_bits; |
| 78 | }; |
| 79 | |
| 80 | /* private information held for every overlayfs dentry */ |
| 81 | struct ovl_entry { |
| 82 | union { |
| 83 | struct { |
| 84 | unsigned long flags; |
| 85 | }; |
| 86 | struct rcu_head rcu; |
| 87 | }; |
| 88 | unsigned numlower; |
| 89 | struct ovl_path lowerstack[]; |
| 90 | }; |
| 91 | |
| 92 | struct ovl_entry *ovl_alloc_entry(unsigned int numlower); |
| 93 | |
| 94 | static inline struct ovl_entry *OVL_E(struct dentry *dentry) |
| 95 | { |
| 96 | return (struct ovl_entry *) dentry->d_fsdata; |
| 97 | } |
| 98 | |
| 99 | struct ovl_inode { |
| 100 | union { |
| 101 | struct ovl_dir_cache *cache; /* directory */ |
| 102 | struct inode *lowerdata; /* regular file */ |
| 103 | }; |
| 104 | const char *redirect; |
| 105 | u64 version; |
| 106 | unsigned long flags; |
| 107 | struct inode vfs_inode; |
| 108 | struct dentry *__upperdentry; |
| 109 | struct inode *lower; |
| 110 | |
| 111 | /* synchronize copy up and more */ |
| 112 | struct mutex lock; |
| 113 | }; |
| 114 | |
| 115 | static inline struct ovl_inode *OVL_I(struct inode *inode) |
| 116 | { |
| 117 | return container_of(inode, struct ovl_inode, vfs_inode); |
| 118 | } |
| 119 | |
| 120 | static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi) |
| 121 | { |
| 122 | return READ_ONCE(oi->__upperdentry); |
| 123 | } |