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; | |
cf9e5a73 TH |
83 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
84 | struct lockdep_map dep_map; | |
85 | #endif | |
86 | /* the following two fields are published */ | |
adc5e8b5 TH |
87 | struct kernfs_node *parent; |
88 | const char *name; | |
cf9e5a73 | 89 | |
adc5e8b5 | 90 | struct rb_node rb; |
cf9e5a73 TH |
91 | |
92 | union { | |
324a56e1 | 93 | struct kernfs_node *removed_list; |
cf9e5a73 TH |
94 | } u; |
95 | ||
adc5e8b5 TH |
96 | const void *ns; /* namespace tag */ |
97 | unsigned int hash; /* ns + name hash */ | |
cf9e5a73 | 98 | union { |
adc5e8b5 TH |
99 | struct kernfs_elem_dir dir; |
100 | struct kernfs_elem_symlink symlink; | |
101 | struct kernfs_elem_attr attr; | |
cf9e5a73 TH |
102 | }; |
103 | ||
104 | void *priv; | |
105 | ||
adc5e8b5 TH |
106 | unsigned short flags; |
107 | umode_t mode; | |
108 | unsigned int ino; | |
c525aadd | 109 | struct kernfs_iattrs *iattr; |
cf9e5a73 | 110 | }; |
b8441ed2 | 111 | |
80b9bbef TH |
112 | /* |
113 | * kernfs_dir_ops may be specified on kernfs_create_root() to support | |
114 | * directory manipulation syscalls. These optional callbacks are invoked | |
115 | * on the matching syscalls and can perform any kernfs operations which | |
116 | * don't necessarily have to be the exact operation requested. | |
117 | */ | |
118 | struct kernfs_dir_ops { | |
119 | int (*mkdir)(struct kernfs_node *parent, const char *name, | |
120 | umode_t mode); | |
121 | int (*rmdir)(struct kernfs_node *kn); | |
122 | int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent, | |
123 | const char *new_name); | |
124 | }; | |
125 | ||
ba7443bc TH |
126 | struct kernfs_root { |
127 | /* published fields */ | |
324a56e1 | 128 | struct kernfs_node *kn; |
bc755553 TH |
129 | |
130 | /* private fields, do not use outside kernfs proper */ | |
131 | struct ida ino_ida; | |
80b9bbef | 132 | struct kernfs_dir_ops *dir_ops; |
ea1c472d | 133 | wait_queue_head_t deactivate_waitq; |
ba7443bc TH |
134 | }; |
135 | ||
c525aadd | 136 | struct kernfs_open_file { |
dd8a5b03 | 137 | /* published fields */ |
324a56e1 | 138 | struct kernfs_node *kn; |
dd8a5b03 TH |
139 | struct file *file; |
140 | ||
141 | /* private fields, do not use outside kernfs proper */ | |
142 | struct mutex mutex; | |
143 | int event; | |
144 | struct list_head list; | |
145 | ||
146 | bool mmapped; | |
147 | const struct vm_operations_struct *vm_ops; | |
148 | }; | |
149 | ||
f6acf8bb TH |
150 | struct kernfs_ops { |
151 | /* | |
152 | * Read is handled by either seq_file or raw_read(). | |
153 | * | |
d19b9846 TH |
154 | * If seq_show() is present, seq_file path is active. Other seq |
155 | * operations are optional and if not implemented, the behavior is | |
156 | * equivalent to single_open(). @sf->private points to the | |
c525aadd | 157 | * associated kernfs_open_file. |
f6acf8bb TH |
158 | * |
159 | * read() is bounced through kernel buffer and a read larger than | |
160 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
161 | */ | |
162 | int (*seq_show)(struct seq_file *sf, void *v); | |
d19b9846 TH |
163 | |
164 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
165 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
166 | void (*seq_stop)(struct seq_file *sf, void *v); | |
f6acf8bb | 167 | |
c525aadd | 168 | ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
169 | loff_t off); |
170 | ||
171 | /* | |
172 | * write() is bounced through kernel buffer and a write larger than | |
173 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
174 | */ | |
c525aadd | 175 | ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
176 | loff_t off); |
177 | ||
c525aadd | 178 | int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma); |
517e64f5 TH |
179 | |
180 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
181 | struct lock_class_key lockdep_key; | |
182 | #endif | |
f6acf8bb TH |
183 | }; |
184 | ||
879f40d1 TH |
185 | #ifdef CONFIG_SYSFS |
186 | ||
df23fc39 | 187 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 | 188 | { |
df23fc39 | 189 | return kn->flags & KERNFS_TYPE_MASK; |
cf9e5a73 TH |
190 | } |
191 | ||
192 | /** | |
193 | * kernfs_enable_ns - enable namespace under a directory | |
324a56e1 | 194 | * @kn: directory of interest, should be empty |
cf9e5a73 | 195 | * |
324a56e1 TH |
196 | * This is to be called right after @kn is created to enable namespace |
197 | * under it. All children of @kn must have non-NULL namespace tags and | |
cf9e5a73 TH |
198 | * only the ones which match the super_block's tag will be visible. |
199 | */ | |
324a56e1 | 200 | static inline void kernfs_enable_ns(struct kernfs_node *kn) |
cf9e5a73 | 201 | { |
df23fc39 | 202 | WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR); |
adc5e8b5 | 203 | WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children)); |
df23fc39 | 204 | kn->flags |= KERNFS_NS; |
cf9e5a73 TH |
205 | } |
206 | ||
ac9bba03 TH |
207 | /** |
208 | * kernfs_ns_enabled - test whether namespace is enabled | |
324a56e1 | 209 | * @kn: the node to test |
ac9bba03 TH |
210 | * |
211 | * Test whether namespace filtering is enabled for the children of @ns. | |
212 | */ | |
324a56e1 | 213 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 | 214 | { |
df23fc39 | 215 | return kn->flags & KERNFS_NS; |
ac9bba03 TH |
216 | } |
217 | ||
324a56e1 TH |
218 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
219 | const char *name, const void *ns); | |
220 | void kernfs_get(struct kernfs_node *kn); | |
221 | void kernfs_put(struct kernfs_node *kn); | |
ccf73cf3 | 222 | |
80b9bbef TH |
223 | struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, |
224 | void *priv); | |
ba7443bc TH |
225 | void kernfs_destroy_root(struct kernfs_root *root); |
226 | ||
324a56e1 | 227 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
bb8b9d09 TH |
228 | const char *name, umode_t mode, |
229 | void *priv, const void *ns); | |
2063d608 TH |
230 | struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, |
231 | const char *name, | |
232 | umode_t mode, loff_t size, | |
233 | const struct kernfs_ops *ops, | |
234 | void *priv, const void *ns, | |
235 | bool name_is_static, | |
236 | struct lock_class_key *key); | |
324a56e1 TH |
237 | struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, |
238 | const char *name, | |
239 | struct kernfs_node *target); | |
240 | void kernfs_remove(struct kernfs_node *kn); | |
241 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, | |
879f40d1 | 242 | const void *ns); |
324a56e1 | 243 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
890ece16 | 244 | const char *new_name, const void *new_ns); |
324a56e1 TH |
245 | int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); |
246 | void kernfs_notify(struct kernfs_node *kn); | |
879f40d1 | 247 | |
4b93dc9b TH |
248 | const void *kernfs_super_ns(struct super_block *sb); |
249 | struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
250 | struct kernfs_root *root, const void *ns); | |
251 | void kernfs_kill_sb(struct super_block *sb); | |
252 | ||
253 | void kernfs_init(void); | |
254 | ||
879f40d1 TH |
255 | #else /* CONFIG_SYSFS */ |
256 | ||
df23fc39 | 257 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 TH |
258 | { return 0; } /* whatever */ |
259 | ||
324a56e1 | 260 | static inline void kernfs_enable_ns(struct kernfs_node *kn) { } |
cf9e5a73 | 261 | |
324a56e1 | 262 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 TH |
263 | { return false; } |
264 | ||
324a56e1 TH |
265 | static inline struct kernfs_node * |
266 | kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, | |
ccf73cf3 TH |
267 | const void *ns) |
268 | { return NULL; } | |
269 | ||
324a56e1 TH |
270 | static inline void kernfs_get(struct kernfs_node *kn) { } |
271 | static inline void kernfs_put(struct kernfs_node *kn) { } | |
ccf73cf3 | 272 | |
80b9bbef TH |
273 | static inline struct kernfs_root * |
274 | kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) | |
ba7443bc TH |
275 | { return ERR_PTR(-ENOSYS); } |
276 | ||
277 | static inline void kernfs_destroy_root(struct kernfs_root *root) { } | |
278 | ||
324a56e1 | 279 | static inline struct kernfs_node * |
bb8b9d09 TH |
280 | kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, |
281 | umode_t mode, void *priv, const void *ns) | |
93b2b8e4 TH |
282 | { return ERR_PTR(-ENOSYS); } |
283 | ||
324a56e1 | 284 | static inline struct kernfs_node * |
2063d608 TH |
285 | __kernfs_create_file(struct kernfs_node *parent, const char *name, |
286 | umode_t mode, loff_t size, const struct kernfs_ops *ops, | |
287 | void *priv, const void *ns, bool name_is_static, | |
288 | struct lock_class_key *key) | |
496f7394 TH |
289 | { return ERR_PTR(-ENOSYS); } |
290 | ||
324a56e1 TH |
291 | static inline struct kernfs_node * |
292 | kernfs_create_link(struct kernfs_node *parent, const char *name, | |
293 | struct kernfs_node *target) | |
5d0e26bb TH |
294 | { return ERR_PTR(-ENOSYS); } |
295 | ||
324a56e1 | 296 | static inline void kernfs_remove(struct kernfs_node *kn) { } |
879f40d1 | 297 | |
324a56e1 | 298 | static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn, |
879f40d1 TH |
299 | const char *name, const void *ns) |
300 | { return -ENOSYS; } | |
301 | ||
324a56e1 TH |
302 | static inline int kernfs_rename_ns(struct kernfs_node *kn, |
303 | struct kernfs_node *new_parent, | |
890ece16 TH |
304 | const char *new_name, const void *new_ns) |
305 | { return -ENOSYS; } | |
306 | ||
324a56e1 | 307 | static inline int kernfs_setattr(struct kernfs_node *kn, |
5d60418e TH |
308 | const struct iattr *iattr) |
309 | { return -ENOSYS; } | |
310 | ||
324a56e1 | 311 | static inline void kernfs_notify(struct kernfs_node *kn) { } |
024f6471 | 312 | |
4b93dc9b TH |
313 | static inline const void *kernfs_super_ns(struct super_block *sb) |
314 | { return NULL; } | |
315 | ||
316 | static inline struct dentry * | |
317 | kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
318 | struct kernfs_root *root, const void *ns) | |
319 | { return ERR_PTR(-ENOSYS); } | |
320 | ||
321 | static inline void kernfs_kill_sb(struct super_block *sb) { } | |
322 | ||
323 | static inline void kernfs_init(void) { } | |
324 | ||
879f40d1 TH |
325 | #endif /* CONFIG_SYSFS */ |
326 | ||
324a56e1 TH |
327 | static inline struct kernfs_node * |
328 | kernfs_find_and_get(struct kernfs_node *kn, const char *name) | |
ccf73cf3 | 329 | { |
324a56e1 | 330 | return kernfs_find_and_get_ns(kn, name, NULL); |
ccf73cf3 TH |
331 | } |
332 | ||
324a56e1 | 333 | static inline struct kernfs_node * |
bb8b9d09 TH |
334 | kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode, |
335 | void *priv) | |
93b2b8e4 | 336 | { |
bb8b9d09 | 337 | return kernfs_create_dir_ns(parent, name, mode, priv, NULL); |
93b2b8e4 TH |
338 | } |
339 | ||
324a56e1 TH |
340 | static inline struct kernfs_node * |
341 | kernfs_create_file_ns(struct kernfs_node *parent, const char *name, | |
517e64f5 TH |
342 | umode_t mode, loff_t size, const struct kernfs_ops *ops, |
343 | void *priv, const void *ns) | |
344 | { | |
345 | struct lock_class_key *key = NULL; | |
346 | ||
347 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
348 | key = (struct lock_class_key *)&ops->lockdep_key; | |
349 | #endif | |
2063d608 TH |
350 | return __kernfs_create_file(parent, name, mode, size, ops, priv, ns, |
351 | false, key); | |
517e64f5 TH |
352 | } |
353 | ||
324a56e1 TH |
354 | static inline struct kernfs_node * |
355 | kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode, | |
496f7394 TH |
356 | loff_t size, const struct kernfs_ops *ops, void *priv) |
357 | { | |
358 | return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL); | |
359 | } | |
360 | ||
324a56e1 | 361 | static inline int kernfs_remove_by_name(struct kernfs_node *parent, |
879f40d1 TH |
362 | const char *name) |
363 | { | |
364 | return kernfs_remove_by_name_ns(parent, name, NULL); | |
365 | } | |
366 | ||
4b93dc9b TH |
367 | static inline struct dentry * |
368 | kernfs_mount(struct file_system_type *fs_type, int flags, | |
369 | struct kernfs_root *root) | |
370 | { | |
371 | return kernfs_mount_ns(fs_type, flags, root, NULL); | |
372 | } | |
373 | ||
b8441ed2 | 374 | #endif /* __LINUX_KERNFS_H */ |