tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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
8struct 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};
21
22struct ovl_sb {
23 struct super_block *sb;
24 dev_t pseudo_dev;
25 /* Unusable (conflicting) uuid */
26 bool bad_uuid;
27 /* Used as a lower layer (but maybe also as upper) */
28 bool is_lower;
29};
30
31struct 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
42struct ovl_path {
43 const struct ovl_layer *layer;
44 struct dentry *dentry;
45};
46
47/* private information held for overlayfs's superblock */
48struct ovl_fs {
49 struct vfsmount *upper_mnt;
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 /* 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 /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
77 int xino_mode;
78};
79
80static inline struct ovl_fs *OVL_FS(struct super_block *sb)
81{
82 return (struct ovl_fs *)sb->s_fs_info;
83}
84
85/* private information held for every overlayfs dentry */
86struct ovl_entry {
87 union {
88 struct {
89 unsigned long flags;
90 };
91 struct rcu_head rcu;
92 };
93 unsigned numlower;
94 struct ovl_path lowerstack[];
95};
96
97struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
98
99static inline struct ovl_entry *OVL_E(struct dentry *dentry)
100{
101 return (struct ovl_entry *) dentry->d_fsdata;
102}
103
104struct ovl_inode {
105 union {
106 struct ovl_dir_cache *cache; /* directory */
107 struct inode *lowerdata; /* regular file */
108 };
109 const char *redirect;
110 u64 version;
111 unsigned long flags;
112 struct inode vfs_inode;
113 struct dentry *__upperdentry;
114 struct inode *lower;
115
116 /* synchronize copy up and more */
117 struct mutex lock;
118};
119
120static inline struct ovl_inode *OVL_I(struct inode *inode)
121{
122 return container_of(inode, struct ovl_inode, vfs_inode);
123}
124
125static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
126{
127 return READ_ONCE(oi->__upperdentry);
128}