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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 *upperdir;
10 char *workdir;
11 char **lowerdirs;
12 bool default_permissions;
13 int redirect_mode;
14 int verity_mode;
15 bool index;
16 int uuid;
17 bool nfs_export;
18 int xino;
19 bool metacopy;
20 bool userxattr;
21 bool ovl_volatile;
22};
23
24struct ovl_sb {
25 struct super_block *sb;
26 dev_t pseudo_dev;
27 /* Unusable (conflicting) uuid */
28 bool bad_uuid;
29 /* Used as a lower layer (but maybe also as upper) */
30 bool is_lower;
31};
32
33struct ovl_layer {
34 /* ovl_free_fs() relies on @mnt being the first member! */
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 /* xwhiteouts were found on this layer */
44 bool has_xwhiteouts;
45};
46
47struct ovl_path {
48 const struct ovl_layer *layer;
49 struct dentry *dentry;
50};
51
52struct ovl_entry {
53 unsigned int __numlower;
54 struct ovl_path __lowerstack[];
55};
56
57/* private information held for overlayfs's superblock */
58struct ovl_fs {
59 unsigned int numlayer;
60 /* Number of unique fs among layers including upper fs */
61 unsigned int numfs;
62 /* Number of data-only lower layers */
63 unsigned int numdatalayer;
64 struct ovl_layer *layers;
65 struct ovl_sb *fs;
66 /* workbasedir is the path at workdir= mount option */
67 struct dentry *workbasedir;
68 /* workdir is the 'work' or 'index' directory under workbasedir */
69 struct dentry *workdir;
70 long namelen;
71 /* pathnames of lower and upper dirs, for show_options */
72 struct ovl_config config;
73 /* creds of process who forced instantiation of super block */
74 const struct cred *creator_cred;
75 bool tmpfile;
76 bool noxattr;
77 bool nofh;
78 /* Did we take the inuse lock? */
79 bool upperdir_locked;
80 bool workdir_locked;
81 /* Traps in ovl inode cache */
82 struct inode *workbasedir_trap;
83 struct inode *workdir_trap;
84 /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
85 int xino_mode;
86 /* For allocation of non-persistent inode numbers */
87 atomic_long_t last_ino;
88 /* Shared whiteout cache */
89 struct dentry *whiteout;
90 bool no_shared_whiteout;
91 /* r/o snapshot of upperdir sb's only taken on volatile mounts */
92 errseq_t errseq;
93};
94
95/* Number of lower layers, not including data-only layers */
96static inline unsigned int ovl_numlowerlayer(struct ovl_fs *ofs)
97{
98 return ofs->numlayer - ofs->numdatalayer - 1;
99}
100
101static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
102{
103 return ofs->layers[0].mnt;
104}
105
106static inline struct mnt_idmap *ovl_upper_mnt_idmap(struct ovl_fs *ofs)
107{
108 return mnt_idmap(ovl_upper_mnt(ofs));
109}
110
111extern struct file_system_type ovl_fs_type;
112
113static inline struct ovl_fs *OVL_FS(struct super_block *sb)
114{
115 if (IS_ENABLED(CONFIG_OVERLAY_FS_DEBUG))
116 WARN_ON_ONCE(sb->s_type != &ovl_fs_type);
117
118 return (struct ovl_fs *)sb->s_fs_info;
119}
120
121static inline bool ovl_should_sync(struct ovl_fs *ofs)
122{
123 return !ofs->config.ovl_volatile;
124}
125
126static inline unsigned int ovl_numlower(struct ovl_entry *oe)
127{
128 return oe ? oe->__numlower : 0;
129}
130
131static inline struct ovl_path *ovl_lowerstack(struct ovl_entry *oe)
132{
133 return ovl_numlower(oe) ? oe->__lowerstack : NULL;
134}
135
136static inline struct ovl_path *ovl_lowerpath(struct ovl_entry *oe)
137{
138 return ovl_lowerstack(oe);
139}
140
141static inline struct ovl_path *ovl_lowerdata(struct ovl_entry *oe)
142{
143 struct ovl_path *lowerstack = ovl_lowerstack(oe);
144
145 return lowerstack ? &lowerstack[oe->__numlower - 1] : NULL;
146}
147
148/* May return NULL if lazy lookup of lowerdata is needed */
149static inline struct dentry *ovl_lowerdata_dentry(struct ovl_entry *oe)
150{
151 struct ovl_path *lowerdata = ovl_lowerdata(oe);
152
153 return lowerdata ? READ_ONCE(lowerdata->dentry) : NULL;
154}
155
156/* private information held for every overlayfs dentry */
157static inline unsigned long *OVL_E_FLAGS(struct dentry *dentry)
158{
159 return (unsigned long *) &dentry->d_fsdata;
160}
161
162struct ovl_inode {
163 union {
164 struct ovl_dir_cache *cache; /* directory */
165 const char *lowerdata_redirect; /* regular file */
166 };
167 const char *redirect;
168 u64 version;
169 unsigned long flags;
170 struct inode vfs_inode;
171 struct dentry *__upperdentry;
172 struct ovl_entry *oe;
173
174 /* synchronize copy up and more */
175 struct mutex lock;
176};
177
178static inline struct ovl_inode *OVL_I(struct inode *inode)
179{
180 return container_of(inode, struct ovl_inode, vfs_inode);
181}
182
183static inline struct ovl_entry *OVL_I_E(struct inode *inode)
184{
185 return inode ? OVL_I(inode)->oe : NULL;
186}
187
188static inline struct ovl_entry *OVL_E(struct dentry *dentry)
189{
190 return OVL_I_E(d_inode(dentry));
191}
192
193static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
194{
195 return READ_ONCE(oi->__upperdentry);
196}
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 user_namespace *ovl_upper_mnt_userns(struct ovl_fs *ofs)
94{
95 return mnt_user_ns(ovl_upper_mnt(ofs));
96}
97
98static inline struct ovl_fs *OVL_FS(struct super_block *sb)
99{
100 return (struct ovl_fs *)sb->s_fs_info;
101}
102
103static inline bool ovl_should_sync(struct ovl_fs *ofs)
104{
105 return !ofs->config.ovl_volatile;
106}
107
108/* private information held for every overlayfs dentry */
109struct ovl_entry {
110 union {
111 struct {
112 unsigned long flags;
113 };
114 struct rcu_head rcu;
115 };
116 unsigned numlower;
117 struct ovl_path lowerstack[];
118};
119
120struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
121
122static inline struct ovl_entry *OVL_E(struct dentry *dentry)
123{
124 return (struct ovl_entry *) dentry->d_fsdata;
125}
126
127struct ovl_inode {
128 union {
129 struct ovl_dir_cache *cache; /* directory */
130 struct inode *lowerdata; /* regular file */
131 };
132 const char *redirect;
133 u64 version;
134 unsigned long flags;
135 struct inode vfs_inode;
136 struct dentry *__upperdentry;
137 struct ovl_path lowerpath;
138
139 /* synchronize copy up and more */
140 struct mutex lock;
141};
142
143static inline struct ovl_inode *OVL_I(struct inode *inode)
144{
145 return container_of(inode, struct ovl_inode, vfs_inode);
146}
147
148static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
149{
150 return READ_ONCE(oi->__upperdentry);
151}