Commit | Line | Data |
---|---|---|
b8441ed2 TH |
1 | /* |
2 | * kernfs.h - pseudo filesystem decoupled from vfs locking | |
3 | * | |
4 | * This file is released under the GPLv2. | |
5 | */ | |
6 | ||
7 | #ifndef __LINUX_KERNFS_H | |
8 | #define __LINUX_KERNFS_H | |
9 | ||
879f40d1 | 10 | #include <linux/kernel.h> |
5d0e26bb | 11 | #include <linux/err.h> |
dd8a5b03 TH |
12 | #include <linux/list.h> |
13 | #include <linux/mutex.h> | |
bc755553 | 14 | #include <linux/idr.h> |
517e64f5 | 15 | #include <linux/lockdep.h> |
cf9e5a73 TH |
16 | #include <linux/rbtree.h> |
17 | #include <linux/atomic.h> | |
ea1c472d | 18 | #include <linux/wait.h> |
879f40d1 | 19 | |
5d60418e TH |
20 | struct file; |
21 | struct iattr; | |
dd8a5b03 TH |
22 | struct seq_file; |
23 | struct vm_area_struct; | |
4b93dc9b TH |
24 | struct super_block; |
25 | struct file_system_type; | |
5d60418e | 26 | |
c525aadd TH |
27 | struct kernfs_open_node; |
28 | struct kernfs_iattrs; | |
cf9e5a73 TH |
29 | |
30 | enum kernfs_node_type { | |
df23fc39 TH |
31 | KERNFS_DIR = 0x0001, |
32 | KERNFS_FILE = 0x0002, | |
33 | KERNFS_LINK = 0x0004, | |
cf9e5a73 TH |
34 | }; |
35 | ||
df23fc39 | 36 | #define KERNFS_TYPE_MASK 0x000f |
df23fc39 | 37 | #define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK |
cf9e5a73 TH |
38 | |
39 | enum kernfs_node_flag { | |
45a140e5 | 40 | KERNFS_JUST_DEACTIVATED = 0x0010, /* used to aid lockdep annotation */ |
df23fc39 TH |
41 | KERNFS_NS = 0x0020, |
42 | KERNFS_HAS_SEQ_SHOW = 0x0040, | |
43 | KERNFS_HAS_MMAP = 0x0080, | |
44 | KERNFS_LOCKDEP = 0x0100, | |
2063d608 | 45 | KERNFS_STATIC_NAME = 0x0200, |
cf9e5a73 TH |
46 | }; |
47 | ||
324a56e1 TH |
48 | /* type-specific structures for kernfs_node union members */ |
49 | struct kernfs_elem_dir { | |
cf9e5a73 | 50 | unsigned long subdirs; |
adc5e8b5 | 51 | /* children rbtree starts here and goes through kn->rb */ |
cf9e5a73 TH |
52 | struct rb_root children; |
53 | ||
54 | /* | |
55 | * The kernfs hierarchy this directory belongs to. This fits | |
324a56e1 | 56 | * better directly in kernfs_node but is here to save space. |
cf9e5a73 TH |
57 | */ |
58 | struct kernfs_root *root; | |
59 | }; | |
60 | ||
324a56e1 TH |
61 | struct kernfs_elem_symlink { |
62 | struct kernfs_node *target_kn; | |
cf9e5a73 TH |
63 | }; |
64 | ||
324a56e1 | 65 | struct kernfs_elem_attr { |
cf9e5a73 | 66 | const struct kernfs_ops *ops; |
c525aadd | 67 | struct kernfs_open_node *open; |
cf9e5a73 TH |
68 | loff_t size; |
69 | }; | |
70 | ||
71 | /* | |
324a56e1 TH |
72 | * kernfs_node - the building block of kernfs hierarchy. Each and every |
73 | * kernfs node is represented by single kernfs_node. Most fields are | |
cf9e5a73 TH |
74 | * private to kernfs and shouldn't be accessed directly by kernfs users. |
75 | * | |
324a56e1 TH |
76 | * As long as s_count reference is held, the kernfs_node itself is |
77 | * accessible. Dereferencing elem or any other outer entity requires | |
78 | * active reference. | |
cf9e5a73 | 79 | */ |
324a56e1 | 80 | struct kernfs_node { |
adc5e8b5 TH |
81 | atomic_t count; |
82 | atomic_t active; | |
9f010c2a TH |
83 | int deact_depth; |
84 | unsigned int hash; /* ns + name hash */ | |
cf9e5a73 TH |
85 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
86 | struct lockdep_map dep_map; | |
87 | #endif | |
88 | /* the following two fields are published */ | |
adc5e8b5 TH |
89 | struct kernfs_node *parent; |
90 | const char *name; | |
cf9e5a73 | 91 | |
adc5e8b5 | 92 | struct rb_node rb; |
cf9e5a73 | 93 | |
adc5e8b5 | 94 | const void *ns; /* namespace tag */ |
cf9e5a73 | 95 | union { |
adc5e8b5 TH |
96 | struct kernfs_elem_dir dir; |
97 | struct kernfs_elem_symlink symlink; | |
98 | struct kernfs_elem_attr attr; | |
cf9e5a73 TH |
99 | }; |
100 | ||
101 | void *priv; | |
102 | ||
adc5e8b5 TH |
103 | unsigned short flags; |
104 | umode_t mode; | |
105 | unsigned int ino; | |
c525aadd | 106 | struct kernfs_iattrs *iattr; |
cf9e5a73 | 107 | }; |
b8441ed2 | 108 | |
80b9bbef TH |
109 | /* |
110 | * kernfs_dir_ops may be specified on kernfs_create_root() to support | |
111 | * directory manipulation syscalls. These optional callbacks are invoked | |
112 | * on the matching syscalls and can perform any kernfs operations which | |
113 | * don't necessarily have to be the exact operation requested. | |
114 | */ | |
115 | struct kernfs_dir_ops { | |
116 | int (*mkdir)(struct kernfs_node *parent, const char *name, | |
117 | umode_t mode); | |
118 | int (*rmdir)(struct kernfs_node *kn); | |
119 | int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent, | |
120 | const char *new_name); | |
121 | }; | |
122 | ||
ba7443bc TH |
123 | struct kernfs_root { |
124 | /* published fields */ | |
324a56e1 | 125 | struct kernfs_node *kn; |
bc755553 TH |
126 | |
127 | /* private fields, do not use outside kernfs proper */ | |
128 | struct ida ino_ida; | |
80b9bbef | 129 | struct kernfs_dir_ops *dir_ops; |
ea1c472d | 130 | wait_queue_head_t deactivate_waitq; |
ba7443bc TH |
131 | }; |
132 | ||
c525aadd | 133 | struct kernfs_open_file { |
dd8a5b03 | 134 | /* published fields */ |
324a56e1 | 135 | struct kernfs_node *kn; |
dd8a5b03 TH |
136 | struct file *file; |
137 | ||
138 | /* private fields, do not use outside kernfs proper */ | |
139 | struct mutex mutex; | |
140 | int event; | |
141 | struct list_head list; | |
142 | ||
143 | bool mmapped; | |
144 | const struct vm_operations_struct *vm_ops; | |
145 | }; | |
146 | ||
f6acf8bb TH |
147 | struct kernfs_ops { |
148 | /* | |
149 | * Read is handled by either seq_file or raw_read(). | |
150 | * | |
d19b9846 TH |
151 | * If seq_show() is present, seq_file path is active. Other seq |
152 | * operations are optional and if not implemented, the behavior is | |
153 | * equivalent to single_open(). @sf->private points to the | |
c525aadd | 154 | * associated kernfs_open_file. |
f6acf8bb TH |
155 | * |
156 | * read() is bounced through kernel buffer and a read larger than | |
157 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
158 | */ | |
159 | int (*seq_show)(struct seq_file *sf, void *v); | |
d19b9846 TH |
160 | |
161 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
162 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
163 | void (*seq_stop)(struct seq_file *sf, void *v); | |
f6acf8bb | 164 | |
c525aadd | 165 | ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
166 | loff_t off); |
167 | ||
168 | /* | |
169 | * write() is bounced through kernel buffer and a write larger than | |
170 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
171 | */ | |
c525aadd | 172 | ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
173 | loff_t off); |
174 | ||
c525aadd | 175 | int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma); |
517e64f5 TH |
176 | |
177 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
178 | struct lock_class_key lockdep_key; | |
179 | #endif | |
f6acf8bb TH |
180 | }; |
181 | ||
879f40d1 TH |
182 | #ifdef CONFIG_SYSFS |
183 | ||
df23fc39 | 184 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 | 185 | { |
df23fc39 | 186 | return kn->flags & KERNFS_TYPE_MASK; |
cf9e5a73 TH |
187 | } |
188 | ||
189 | /** | |
190 | * kernfs_enable_ns - enable namespace under a directory | |
324a56e1 | 191 | * @kn: directory of interest, should be empty |
cf9e5a73 | 192 | * |
324a56e1 TH |
193 | * This is to be called right after @kn is created to enable namespace |
194 | * under it. All children of @kn must have non-NULL namespace tags and | |
cf9e5a73 TH |
195 | * only the ones which match the super_block's tag will be visible. |
196 | */ | |
324a56e1 | 197 | static inline void kernfs_enable_ns(struct kernfs_node *kn) |
cf9e5a73 | 198 | { |
df23fc39 | 199 | WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR); |
adc5e8b5 | 200 | WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children)); |
df23fc39 | 201 | kn->flags |= KERNFS_NS; |
cf9e5a73 TH |
202 | } |
203 | ||
ac9bba03 TH |
204 | /** |
205 | * kernfs_ns_enabled - test whether namespace is enabled | |
324a56e1 | 206 | * @kn: the node to test |
ac9bba03 TH |
207 | * |
208 | * Test whether namespace filtering is enabled for the children of @ns. | |
209 | */ | |
324a56e1 | 210 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 | 211 | { |
df23fc39 | 212 | return kn->flags & KERNFS_NS; |
ac9bba03 TH |
213 | } |
214 | ||
324a56e1 TH |
215 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
216 | const char *name, const void *ns); | |
217 | void kernfs_get(struct kernfs_node *kn); | |
218 | void kernfs_put(struct kernfs_node *kn); | |
ccf73cf3 | 219 | |
80b9bbef TH |
220 | struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, |
221 | void *priv); | |
ba7443bc TH |
222 | void kernfs_destroy_root(struct kernfs_root *root); |
223 | ||
324a56e1 | 224 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
bb8b9d09 TH |
225 | const char *name, umode_t mode, |
226 | void *priv, const void *ns); | |
2063d608 TH |
227 | struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, |
228 | const char *name, | |
229 | umode_t mode, loff_t size, | |
230 | const struct kernfs_ops *ops, | |
231 | void *priv, const void *ns, | |
232 | bool name_is_static, | |
233 | struct lock_class_key *key); | |
324a56e1 TH |
234 | struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, |
235 | const char *name, | |
236 | struct kernfs_node *target); | |
9f010c2a TH |
237 | void kernfs_deactivate(struct kernfs_node *kn); |
238 | void kernfs_reactivate(struct kernfs_node *kn); | |
239 | void kernfs_deactivate_self(struct kernfs_node *kn); | |
240 | void kernfs_reactivate_self(struct kernfs_node *kn); | |
324a56e1 TH |
241 | void kernfs_remove(struct kernfs_node *kn); |
242 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, | |
879f40d1 | 243 | const void *ns); |
324a56e1 | 244 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
890ece16 | 245 | const char *new_name, const void *new_ns); |
324a56e1 TH |
246 | int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); |
247 | void kernfs_notify(struct kernfs_node *kn); | |
879f40d1 | 248 | |
4b93dc9b TH |
249 | const void *kernfs_super_ns(struct super_block *sb); |
250 | struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
251 | struct kernfs_root *root, const void *ns); | |
252 | void kernfs_kill_sb(struct super_block *sb); | |
253 | ||
254 | void kernfs_init(void); | |
255 | ||
879f40d1 TH |
256 | #else /* CONFIG_SYSFS */ |
257 | ||
df23fc39 | 258 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 TH |
259 | { return 0; } /* whatever */ |
260 | ||
324a56e1 | 261 | static inline void kernfs_enable_ns(struct kernfs_node *kn) { } |
cf9e5a73 | 262 | |
324a56e1 | 263 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 TH |
264 | { return false; } |
265 | ||
324a56e1 TH |
266 | static inline struct kernfs_node * |
267 | kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, | |
ccf73cf3 TH |
268 | const void *ns) |
269 | { return NULL; } | |
270 | ||
324a56e1 TH |
271 | static inline void kernfs_get(struct kernfs_node *kn) { } |
272 | static inline void kernfs_put(struct kernfs_node *kn) { } | |
ccf73cf3 | 273 | |
80b9bbef TH |
274 | static inline struct kernfs_root * |
275 | kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) | |
ba7443bc TH |
276 | { return ERR_PTR(-ENOSYS); } |
277 | ||
278 | static inline void kernfs_destroy_root(struct kernfs_root *root) { } | |
279 | ||
324a56e1 | 280 | static inline struct kernfs_node * |
bb8b9d09 TH |
281 | kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, |
282 | umode_t mode, void *priv, const void *ns) | |
93b2b8e4 TH |
283 | { return ERR_PTR(-ENOSYS); } |
284 | ||
324a56e1 | 285 | static inline struct kernfs_node * |
2063d608 TH |
286 | __kernfs_create_file(struct kernfs_node *parent, const char *name, |
287 | umode_t mode, loff_t size, const struct kernfs_ops *ops, | |
288 | void *priv, const void *ns, bool name_is_static, | |
289 | struct lock_class_key *key) | |
496f7394 TH |
290 | { return ERR_PTR(-ENOSYS); } |
291 | ||
324a56e1 TH |
292 | static inline struct kernfs_node * |
293 | kernfs_create_link(struct kernfs_node *parent, const char *name, | |
294 | struct kernfs_node *target) | |
5d0e26bb TH |
295 | { return ERR_PTR(-ENOSYS); } |
296 | ||
324a56e1 | 297 | static inline void kernfs_remove(struct kernfs_node *kn) { } |
879f40d1 | 298 | |
324a56e1 | 299 | static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn, |
879f40d1 TH |
300 | const char *name, const void *ns) |
301 | { return -ENOSYS; } | |
302 | ||
324a56e1 TH |
303 | static inline int kernfs_rename_ns(struct kernfs_node *kn, |
304 | struct kernfs_node *new_parent, | |
890ece16 TH |
305 | const char *new_name, const void *new_ns) |
306 | { return -ENOSYS; } | |
307 | ||
324a56e1 | 308 | static inline int kernfs_setattr(struct kernfs_node *kn, |
5d60418e TH |
309 | const struct iattr *iattr) |
310 | { return -ENOSYS; } | |
311 | ||
324a56e1 | 312 | static inline void kernfs_notify(struct kernfs_node *kn) { } |
024f6471 | 313 | |
4b93dc9b TH |
314 | static inline const void *kernfs_super_ns(struct super_block *sb) |
315 | { return NULL; } | |
316 | ||
317 | static inline struct dentry * | |
318 | kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
319 | struct kernfs_root *root, const void *ns) | |
320 | { return ERR_PTR(-ENOSYS); } | |
321 | ||
322 | static inline void kernfs_kill_sb(struct super_block *sb) { } | |
323 | ||
324 | static inline void kernfs_init(void) { } | |
325 | ||
879f40d1 TH |
326 | #endif /* CONFIG_SYSFS */ |
327 | ||
324a56e1 TH |
328 | static inline struct kernfs_node * |
329 | kernfs_find_and_get(struct kernfs_node *kn, const char *name) | |
ccf73cf3 | 330 | { |
324a56e1 | 331 | return kernfs_find_and_get_ns(kn, name, NULL); |
ccf73cf3 TH |
332 | } |
333 | ||
324a56e1 | 334 | static inline struct kernfs_node * |
bb8b9d09 TH |
335 | kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode, |
336 | void *priv) | |
93b2b8e4 | 337 | { |
bb8b9d09 | 338 | return kernfs_create_dir_ns(parent, name, mode, priv, NULL); |
93b2b8e4 TH |
339 | } |
340 | ||
324a56e1 TH |
341 | static inline struct kernfs_node * |
342 | kernfs_create_file_ns(struct kernfs_node *parent, const char *name, | |
517e64f5 TH |
343 | umode_t mode, loff_t size, const struct kernfs_ops *ops, |
344 | void *priv, const void *ns) | |
345 | { | |
346 | struct lock_class_key *key = NULL; | |
347 | ||
348 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
349 | key = (struct lock_class_key *)&ops->lockdep_key; | |
350 | #endif | |
2063d608 TH |
351 | return __kernfs_create_file(parent, name, mode, size, ops, priv, ns, |
352 | false, key); | |
517e64f5 TH |
353 | } |
354 | ||
324a56e1 TH |
355 | static inline struct kernfs_node * |
356 | kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode, | |
496f7394 TH |
357 | loff_t size, const struct kernfs_ops *ops, void *priv) |
358 | { | |
359 | return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL); | |
360 | } | |
361 | ||
324a56e1 | 362 | static inline int kernfs_remove_by_name(struct kernfs_node *parent, |
879f40d1 TH |
363 | const char *name) |
364 | { | |
365 | return kernfs_remove_by_name_ns(parent, name, NULL); | |
366 | } | |
367 | ||
4b93dc9b TH |
368 | static inline struct dentry * |
369 | kernfs_mount(struct file_system_type *fs_type, int flags, | |
370 | struct kernfs_root *root) | |
371 | { | |
372 | return kernfs_mount_ns(fs_type, flags, root, NULL); | |
373 | } | |
374 | ||
b8441ed2 | 375 | #endif /* __LINUX_KERNFS_H */ |