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