tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
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 unsigned int numlayer;
50 /* Number of unique fs among layers including upper fs */
51 unsigned int numfs;
52 const struct ovl_layer *layers;
53 struct ovl_sb *fs;
54 /* workbasedir is the path at workdir= mount option */
55 struct dentry *workbasedir;
56 /* workdir is the 'work' directory under workbasedir */
57 struct dentry *workdir;
58 /* index directory listing overlay inodes by origin file handle */
59 struct dentry *indexdir;
60 long namelen;
61 /* pathnames of lower and upper dirs, for show_options */
62 struct ovl_config config;
63 /* creds of process who forced instantiation of super block */
64 const struct cred *creator_cred;
65 bool tmpfile;
66 bool noxattr;
67 /* Did we take the inuse lock? */
68 bool upperdir_locked;
69 bool workdir_locked;
70 bool share_whiteout;
71 /* Traps in ovl inode cache */
72 struct inode *workbasedir_trap;
73 struct inode *workdir_trap;
74 struct inode *indexdir_trap;
75 /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
76 int xino_mode;
77 /* For allocation of non-persistent inode numbers */
78 atomic_long_t last_ino;
79 /* Whiteout dentry cache */
80 struct dentry *whiteout;
81};
82
83static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
84{
85 return ofs->layers[0].mnt;
86}
87
88static inline struct ovl_fs *OVL_FS(struct super_block *sb)
89{
90 return (struct ovl_fs *)sb->s_fs_info;
91}
92
93/* private information held for every overlayfs dentry */
94struct ovl_entry {
95 union {
96 struct {
97 unsigned long flags;
98 };
99 struct rcu_head rcu;
100 };
101 unsigned numlower;
102 struct ovl_path lowerstack[];
103};
104
105struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
106
107static inline struct ovl_entry *OVL_E(struct dentry *dentry)
108{
109 return (struct ovl_entry *) dentry->d_fsdata;
110}
111
112struct ovl_inode {
113 union {
114 struct ovl_dir_cache *cache; /* directory */
115 struct inode *lowerdata; /* regular file */
116 };
117 const char *redirect;
118 u64 version;
119 unsigned long flags;
120 struct inode vfs_inode;
121 struct dentry *__upperdentry;
122 struct inode *lower;
123
124 /* synchronize copy up and more */
125 struct mutex lock;
126};
127
128static inline struct ovl_inode *OVL_I(struct inode *inode)
129{
130 return container_of(inode, struct ovl_inode, vfs_inode);
131}
132
133static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
134{
135 return READ_ONCE(oi->__upperdentry);
136}