1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * kernfs.h - pseudo filesystem decoupled from vfs locking |
4 | */ |
5 | |
6 | #ifndef __LINUX_KERNFS_H |
7 | #define __LINUX_KERNFS_H |
8 | |
9 | #include <linux/err.h> |
10 | #include <linux/list.h> |
11 | #include <linux/mutex.h> |
12 | #include <linux/idr.h> |
13 | #include <linux/lockdep.h> |
14 | #include <linux/rbtree.h> |
15 | #include <linux/atomic.h> |
16 | #include <linux/bug.h> |
17 | #include <linux/types.h> |
18 | #include <linux/uidgid.h> |
19 | #include <linux/wait.h> |
20 | #include <linux/rwsem.h> |
21 | #include <linux/cache.h> |
22 | |
23 | struct file; |
24 | struct dentry; |
25 | struct iattr; |
26 | struct seq_file; |
27 | struct vm_area_struct; |
28 | struct vm_operations_struct; |
29 | struct super_block; |
30 | struct file_system_type; |
31 | struct poll_table_struct; |
32 | struct fs_context; |
33 | |
34 | struct kernfs_fs_context; |
35 | struct kernfs_open_node; |
36 | struct kernfs_iattrs; |
37 | |
38 | /* |
39 | * NR_KERNFS_LOCK_BITS determines size (NR_KERNFS_LOCKS) of hash |
40 | * table of locks. |
41 | * Having a small hash table would impact scalability, since |
42 | * more and more kernfs_node objects will end up using same lock |
43 | * and having a very large hash table would waste memory. |
44 | * |
45 | * At the moment size of hash table of locks is being set based on |
46 | * the number of CPUs as follows: |
47 | * |
48 | * NR_CPU NR_KERNFS_LOCK_BITS NR_KERNFS_LOCKS |
49 | * 1 1 2 |
50 | * 2-3 2 4 |
51 | * 4-7 4 16 |
52 | * 8-15 6 64 |
53 | * 16-31 8 256 |
54 | * 32 and more 10 1024 |
55 | * |
56 | * The above relation between NR_CPU and number of locks is based |
57 | * on some internal experimentation which involved booting qemu |
58 | * with different values of smp, performing some sysfs operations |
59 | * on all CPUs and observing how increase in number of locks impacts |
60 | * completion time of these sysfs operations on each CPU. |
61 | */ |
62 | #ifdef CONFIG_SMP |
63 | #define NR_KERNFS_LOCK_BITS (2 * (ilog2(NR_CPUS < 32 ? NR_CPUS : 32))) |
64 | #else |
65 | #define NR_KERNFS_LOCK_BITS 1 |
66 | #endif |
67 | |
68 | #define NR_KERNFS_LOCKS (1 << NR_KERNFS_LOCK_BITS) |
69 | |
70 | /* |
71 | * There's one kernfs_open_file for each open file and one kernfs_open_node |
72 | * for each kernfs_node with one or more open files. |
73 | * |
74 | * filp->private_data points to seq_file whose ->private points to |
75 | * kernfs_open_file. |
76 | * |
77 | * kernfs_open_files are chained at kernfs_open_node->files, which is |
78 | * protected by kernfs_global_locks.open_file_mutex[i]. |
79 | * |
80 | * To reduce possible contention in sysfs access, arising due to single |
81 | * locks, use an array of locks (e.g. open_file_mutex) and use kernfs_node |
82 | * object address as hash keys to get the index of these locks. |
83 | * |
84 | * Hashed mutexes are safe to use here because operations using these don't |
85 | * rely on global exclusion. |
86 | * |
87 | * In future we intend to replace other global locks with hashed ones as well. |
88 | * kernfs_global_locks acts as a holder for all such hash tables. |
89 | */ |
90 | struct kernfs_global_locks { |
91 | struct mutex open_file_mutex[NR_KERNFS_LOCKS]; |
92 | }; |
93 | |
94 | enum kernfs_node_type { |
95 | KERNFS_DIR = 0x0001, |
96 | KERNFS_FILE = 0x0002, |
97 | KERNFS_LINK = 0x0004, |
98 | }; |
99 | |
100 | #define KERNFS_TYPE_MASK 0x000f |
101 | #define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK |
102 | #define KERNFS_MAX_USER_XATTRS 128 |
103 | #define KERNFS_USER_XATTR_SIZE_LIMIT (128 << 10) |
104 | |
105 | enum kernfs_node_flag { |
106 | KERNFS_ACTIVATED = 0x0010, |
107 | KERNFS_NS = 0x0020, |
108 | KERNFS_HAS_SEQ_SHOW = 0x0040, |
109 | KERNFS_HAS_MMAP = 0x0080, |
110 | KERNFS_LOCKDEP = 0x0100, |
111 | KERNFS_HIDDEN = 0x0200, |
112 | KERNFS_SUICIDAL = 0x0400, |
113 | KERNFS_SUICIDED = 0x0800, |
114 | KERNFS_EMPTY_DIR = 0x1000, |
115 | KERNFS_HAS_RELEASE = 0x2000, |
116 | KERNFS_REMOVING = 0x4000, |
117 | }; |
118 | |
119 | /* @flags for kernfs_create_root() */ |
120 | enum kernfs_root_flag { |
121 | /* |
122 | * kernfs_nodes are created in the deactivated state and invisible. |
123 | * They require explicit kernfs_activate() to become visible. This |
124 | * can be used to make related nodes become visible atomically |
125 | * after all nodes are created successfully. |
126 | */ |
127 | KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001, |
128 | |
129 | /* |
130 | * For regular files, if the opener has CAP_DAC_OVERRIDE, open(2) |
131 | * succeeds regardless of the RW permissions. sysfs had an extra |
132 | * layer of enforcement where open(2) fails with -EACCES regardless |
133 | * of CAP_DAC_OVERRIDE if the permission doesn't have the |
134 | * respective read or write access at all (none of S_IRUGO or |
135 | * S_IWUGO) or the respective operation isn't implemented. The |
136 | * following flag enables that behavior. |
137 | */ |
138 | = 0x0002, |
139 | |
140 | /* |
141 | * The filesystem supports exportfs operation, so userspace can use |
142 | * fhandle to access nodes of the fs. |
143 | */ |
144 | KERNFS_ROOT_SUPPORT_EXPORTOP = 0x0004, |
145 | |
146 | /* |
147 | * Support user xattrs to be written to nodes rooted at this root. |
148 | */ |
149 | KERNFS_ROOT_SUPPORT_USER_XATTR = 0x0008, |
150 | }; |
151 | |
152 | /* type-specific structures for kernfs_node union members */ |
153 | struct kernfs_elem_dir { |
154 | unsigned long subdirs; |
155 | /* children rbtree starts here and goes through kn->rb */ |
156 | struct rb_root children; |
157 | |
158 | /* |
159 | * The kernfs hierarchy this directory belongs to. This fits |
160 | * better directly in kernfs_node but is here to save space. |
161 | */ |
162 | struct kernfs_root *root; |
163 | /* |
164 | * Monotonic revision counter, used to identify if a directory |
165 | * node has changed during negative dentry revalidation. |
166 | */ |
167 | unsigned long rev; |
168 | }; |
169 | |
170 | struct kernfs_elem_symlink { |
171 | struct kernfs_node *target_kn; |
172 | }; |
173 | |
174 | struct kernfs_elem_attr { |
175 | const struct kernfs_ops *ops; |
176 | struct kernfs_open_node __rcu *open; |
177 | loff_t size; |
178 | struct kernfs_node *notify_next; /* for kernfs_notify() */ |
179 | }; |
180 | |
181 | /* |
182 | * kernfs_node - the building block of kernfs hierarchy. Each and every |
183 | * kernfs node is represented by single kernfs_node. Most fields are |
184 | * private to kernfs and shouldn't be accessed directly by kernfs users. |
185 | * |
186 | * As long as count reference is held, the kernfs_node itself is |
187 | * accessible. Dereferencing elem or any other outer entity requires |
188 | * active reference. |
189 | */ |
190 | struct kernfs_node { |
191 | atomic_t count; |
192 | atomic_t active; |
193 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
194 | struct lockdep_map dep_map; |
195 | #endif |
196 | /* |
197 | * Use kernfs_get_parent() and kernfs_name/path() instead of |
198 | * accessing the following two fields directly. If the node is |
199 | * never moved to a different parent, it is safe to access the |
200 | * parent directly. |
201 | */ |
202 | struct kernfs_node *parent; |
203 | const char *name; |
204 | |
205 | struct rb_node rb; |
206 | |
207 | const void *ns; /* namespace tag */ |
208 | unsigned int hash; /* ns + name hash */ |
209 | union { |
210 | struct kernfs_elem_dir dir; |
211 | struct kernfs_elem_symlink symlink; |
212 | struct kernfs_elem_attr attr; |
213 | }; |
214 | |
215 | void *priv; |
216 | |
217 | /* |
218 | * 64bit unique ID. On 64bit ino setups, id is the ino. On 32bit, |
219 | * the low 32bits are ino and upper generation. |
220 | */ |
221 | u64 id; |
222 | |
223 | unsigned short flags; |
224 | umode_t mode; |
225 | struct kernfs_iattrs *iattr; |
226 | }; |
227 | |
228 | /* |
229 | * kernfs_syscall_ops may be specified on kernfs_create_root() to support |
230 | * syscalls. These optional callbacks are invoked on the matching syscalls |
231 | * and can perform any kernfs operations which don't necessarily have to be |
232 | * the exact operation requested. An active reference is held for each |
233 | * kernfs_node parameter. |
234 | */ |
235 | struct kernfs_syscall_ops { |
236 | int (*show_options)(struct seq_file *sf, struct kernfs_root *root); |
237 | |
238 | int (*mkdir)(struct kernfs_node *parent, const char *name, |
239 | umode_t mode); |
240 | int (*rmdir)(struct kernfs_node *kn); |
241 | int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent, |
242 | const char *new_name); |
243 | int (*show_path)(struct seq_file *sf, struct kernfs_node *kn, |
244 | struct kernfs_root *root); |
245 | }; |
246 | |
247 | struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root); |
248 | |
249 | struct kernfs_open_file { |
250 | /* published fields */ |
251 | struct kernfs_node *kn; |
252 | struct file *file; |
253 | struct seq_file *seq_file; |
254 | void *priv; |
255 | |
256 | /* private fields, do not use outside kernfs proper */ |
257 | struct mutex mutex; |
258 | struct mutex prealloc_mutex; |
259 | int event; |
260 | struct list_head list; |
261 | char *prealloc_buf; |
262 | |
263 | size_t atomic_write_len; |
264 | bool mmapped:1; |
265 | bool released:1; |
266 | const struct vm_operations_struct *vm_ops; |
267 | }; |
268 | |
269 | struct kernfs_ops { |
270 | /* |
271 | * Optional open/release methods. Both are called with |
272 | * @of->seq_file populated. |
273 | */ |
274 | int (*open)(struct kernfs_open_file *of); |
275 | void (*release)(struct kernfs_open_file *of); |
276 | |
277 | /* |
278 | * Read is handled by either seq_file or raw_read(). |
279 | * |
280 | * If seq_show() is present, seq_file path is active. Other seq |
281 | * operations are optional and if not implemented, the behavior is |
282 | * equivalent to single_open(). @sf->private points to the |
283 | * associated kernfs_open_file. |
284 | * |
285 | * read() is bounced through kernel buffer and a read larger than |
286 | * PAGE_SIZE results in partial operation of PAGE_SIZE. |
287 | */ |
288 | int (*seq_show)(struct seq_file *sf, void *v); |
289 | |
290 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); |
291 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); |
292 | void (*seq_stop)(struct seq_file *sf, void *v); |
293 | |
294 | ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes, |
295 | loff_t off); |
296 | |
297 | /* |
298 | * write() is bounced through kernel buffer. If atomic_write_len |
299 | * is not set, a write larger than PAGE_SIZE results in partial |
300 | * operations of PAGE_SIZE chunks. If atomic_write_len is set, |
301 | * writes upto the specified size are executed atomically but |
302 | * larger ones are rejected with -E2BIG. |
303 | */ |
304 | size_t atomic_write_len; |
305 | /* |
306 | * "prealloc" causes a buffer to be allocated at open for |
307 | * all read/write requests. As ->seq_show uses seq_read() |
308 | * which does its own allocation, it is incompatible with |
309 | * ->prealloc. Provide ->read and ->write with ->prealloc. |
310 | */ |
311 | bool prealloc; |
312 | ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, |
313 | loff_t off); |
314 | |
315 | __poll_t (*poll)(struct kernfs_open_file *of, |
316 | struct poll_table_struct *pt); |
317 | |
318 | int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma); |
319 | loff_t (*llseek)(struct kernfs_open_file *of, loff_t offset, int whence); |
320 | }; |
321 | |
322 | /* |
323 | * The kernfs superblock creation/mount parameter context. |
324 | */ |
325 | struct kernfs_fs_context { |
326 | struct kernfs_root *root; /* Root of the hierarchy being mounted */ |
327 | void *ns_tag; /* Namespace tag of the mount (or NULL) */ |
328 | unsigned long magic; /* File system specific magic number */ |
329 | |
330 | /* The following are set/used by kernfs_mount() */ |
331 | bool new_sb_created; /* Set to T if we allocated a new sb */ |
332 | }; |
333 | |
334 | #ifdef CONFIG_KERNFS |
335 | |
336 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
337 | { |
338 | return kn->flags & KERNFS_TYPE_MASK; |
339 | } |
340 | |
341 | static inline ino_t kernfs_id_ino(u64 id) |
342 | { |
343 | /* id is ino if ino_t is 64bit; otherwise, low 32bits */ |
344 | if (sizeof(ino_t) >= sizeof(u64)) |
345 | return id; |
346 | else |
347 | return (u32)id; |
348 | } |
349 | |
350 | static inline u32 kernfs_id_gen(u64 id) |
351 | { |
352 | /* gen is fixed at 1 if ino_t is 64bit; otherwise, high 32bits */ |
353 | if (sizeof(ino_t) >= sizeof(u64)) |
354 | return 1; |
355 | else |
356 | return id >> 32; |
357 | } |
358 | |
359 | static inline ino_t kernfs_ino(struct kernfs_node *kn) |
360 | { |
361 | return kernfs_id_ino(id: kn->id); |
362 | } |
363 | |
364 | static inline ino_t kernfs_gen(struct kernfs_node *kn) |
365 | { |
366 | return kernfs_id_gen(id: kn->id); |
367 | } |
368 | |
369 | /** |
370 | * kernfs_enable_ns - enable namespace under a directory |
371 | * @kn: directory of interest, should be empty |
372 | * |
373 | * This is to be called right after @kn is created to enable namespace |
374 | * under it. All children of @kn must have non-NULL namespace tags and |
375 | * only the ones which match the super_block's tag will be visible. |
376 | */ |
377 | static inline void kernfs_enable_ns(struct kernfs_node *kn) |
378 | { |
379 | WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR); |
380 | WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children)); |
381 | kn->flags |= KERNFS_NS; |
382 | } |
383 | |
384 | /** |
385 | * kernfs_ns_enabled - test whether namespace is enabled |
386 | * @kn: the node to test |
387 | * |
388 | * Test whether namespace filtering is enabled for the children of @ns. |
389 | */ |
390 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
391 | { |
392 | return kn->flags & KERNFS_NS; |
393 | } |
394 | |
395 | int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen); |
396 | int kernfs_path_from_node(struct kernfs_node *root_kn, struct kernfs_node *kn, |
397 | char *buf, size_t buflen); |
398 | void pr_cont_kernfs_name(struct kernfs_node *kn); |
399 | void pr_cont_kernfs_path(struct kernfs_node *kn); |
400 | struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn); |
401 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
402 | const char *name, const void *ns); |
403 | struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, |
404 | const char *path, const void *ns); |
405 | void kernfs_get(struct kernfs_node *kn); |
406 | void kernfs_put(struct kernfs_node *kn); |
407 | |
408 | struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry); |
409 | struct kernfs_root *kernfs_root_from_sb(struct super_block *sb); |
410 | struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn); |
411 | |
412 | struct dentry *kernfs_node_dentry(struct kernfs_node *kn, |
413 | struct super_block *sb); |
414 | struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, |
415 | unsigned int flags, void *priv); |
416 | void kernfs_destroy_root(struct kernfs_root *root); |
417 | |
418 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
419 | const char *name, umode_t mode, |
420 | kuid_t uid, kgid_t gid, |
421 | void *priv, const void *ns); |
422 | struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, |
423 | const char *name); |
424 | struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, |
425 | const char *name, umode_t mode, |
426 | kuid_t uid, kgid_t gid, |
427 | loff_t size, |
428 | const struct kernfs_ops *ops, |
429 | void *priv, const void *ns, |
430 | struct lock_class_key *key); |
431 | struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, |
432 | const char *name, |
433 | struct kernfs_node *target); |
434 | void kernfs_activate(struct kernfs_node *kn); |
435 | void kernfs_show(struct kernfs_node *kn, bool show); |
436 | void kernfs_remove(struct kernfs_node *kn); |
437 | void kernfs_break_active_protection(struct kernfs_node *kn); |
438 | void kernfs_unbreak_active_protection(struct kernfs_node *kn); |
439 | bool kernfs_remove_self(struct kernfs_node *kn); |
440 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, |
441 | const void *ns); |
442 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
443 | const char *new_name, const void *new_ns); |
444 | int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); |
445 | __poll_t kernfs_generic_poll(struct kernfs_open_file *of, |
446 | struct poll_table_struct *pt); |
447 | void kernfs_notify(struct kernfs_node *kn); |
448 | |
449 | int kernfs_xattr_get(struct kernfs_node *kn, const char *name, |
450 | void *value, size_t size); |
451 | int kernfs_xattr_set(struct kernfs_node *kn, const char *name, |
452 | const void *value, size_t size, int flags); |
453 | |
454 | const void *kernfs_super_ns(struct super_block *sb); |
455 | int kernfs_get_tree(struct fs_context *fc); |
456 | void kernfs_free_fs_context(struct fs_context *fc); |
457 | void kernfs_kill_sb(struct super_block *sb); |
458 | |
459 | void kernfs_init(void); |
460 | |
461 | struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root, |
462 | u64 id); |
463 | #else /* CONFIG_KERNFS */ |
464 | |
465 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
466 | { return 0; } /* whatever */ |
467 | |
468 | static inline void kernfs_enable_ns(struct kernfs_node *kn) { } |
469 | |
470 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
471 | { return false; } |
472 | |
473 | static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) |
474 | { return -ENOSYS; } |
475 | |
476 | static inline int kernfs_path_from_node(struct kernfs_node *root_kn, |
477 | struct kernfs_node *kn, |
478 | char *buf, size_t buflen) |
479 | { return -ENOSYS; } |
480 | |
481 | static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { } |
482 | static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { } |
483 | |
484 | static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) |
485 | { return NULL; } |
486 | |
487 | static inline struct kernfs_node * |
488 | kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, |
489 | const void *ns) |
490 | { return NULL; } |
491 | static inline struct kernfs_node * |
492 | kernfs_walk_and_get_ns(struct kernfs_node *parent, const char *path, |
493 | const void *ns) |
494 | { return NULL; } |
495 | |
496 | static inline void kernfs_get(struct kernfs_node *kn) { } |
497 | static inline void kernfs_put(struct kernfs_node *kn) { } |
498 | |
499 | static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) |
500 | { return NULL; } |
501 | |
502 | static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb) |
503 | { return NULL; } |
504 | |
505 | static inline struct inode * |
506 | kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn) |
507 | { return NULL; } |
508 | |
509 | static inline struct kernfs_root * |
510 | kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags, |
511 | void *priv) |
512 | { return ERR_PTR(-ENOSYS); } |
513 | |
514 | static inline void kernfs_destroy_root(struct kernfs_root *root) { } |
515 | |
516 | static inline struct kernfs_node * |
517 | kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, |
518 | umode_t mode, kuid_t uid, kgid_t gid, |
519 | void *priv, const void *ns) |
520 | { return ERR_PTR(-ENOSYS); } |
521 | |
522 | static inline struct kernfs_node * |
523 | __kernfs_create_file(struct kernfs_node *parent, const char *name, |
524 | umode_t mode, kuid_t uid, kgid_t gid, |
525 | loff_t size, const struct kernfs_ops *ops, |
526 | void *priv, const void *ns, struct lock_class_key *key) |
527 | { return ERR_PTR(-ENOSYS); } |
528 | |
529 | static inline struct kernfs_node * |
530 | kernfs_create_link(struct kernfs_node *parent, const char *name, |
531 | struct kernfs_node *target) |
532 | { return ERR_PTR(-ENOSYS); } |
533 | |
534 | static inline void kernfs_activate(struct kernfs_node *kn) { } |
535 | |
536 | static inline void kernfs_remove(struct kernfs_node *kn) { } |
537 | |
538 | static inline bool kernfs_remove_self(struct kernfs_node *kn) |
539 | { return false; } |
540 | |
541 | static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn, |
542 | const char *name, const void *ns) |
543 | { return -ENOSYS; } |
544 | |
545 | static inline int kernfs_rename_ns(struct kernfs_node *kn, |
546 | struct kernfs_node *new_parent, |
547 | const char *new_name, const void *new_ns) |
548 | { return -ENOSYS; } |
549 | |
550 | static inline int kernfs_setattr(struct kernfs_node *kn, |
551 | const struct iattr *iattr) |
552 | { return -ENOSYS; } |
553 | |
554 | static inline __poll_t kernfs_generic_poll(struct kernfs_open_file *of, |
555 | struct poll_table_struct *pt) |
556 | { return -ENOSYS; } |
557 | |
558 | static inline void kernfs_notify(struct kernfs_node *kn) { } |
559 | |
560 | static inline int kernfs_xattr_get(struct kernfs_node *kn, const char *name, |
561 | void *value, size_t size) |
562 | { return -ENOSYS; } |
563 | |
564 | static inline int kernfs_xattr_set(struct kernfs_node *kn, const char *name, |
565 | const void *value, size_t size, int flags) |
566 | { return -ENOSYS; } |
567 | |
568 | static inline const void *kernfs_super_ns(struct super_block *sb) |
569 | { return NULL; } |
570 | |
571 | static inline int kernfs_get_tree(struct fs_context *fc) |
572 | { return -ENOSYS; } |
573 | |
574 | static inline void kernfs_free_fs_context(struct fs_context *fc) { } |
575 | |
576 | static inline void kernfs_kill_sb(struct super_block *sb) { } |
577 | |
578 | static inline void kernfs_init(void) { } |
579 | |
580 | #endif /* CONFIG_KERNFS */ |
581 | |
582 | /** |
583 | * kernfs_path - build full path of a given node |
584 | * @kn: kernfs_node of interest |
585 | * @buf: buffer to copy @kn's name into |
586 | * @buflen: size of @buf |
587 | * |
588 | * If @kn is NULL result will be "(null)". |
589 | * |
590 | * Returns the length of the full path. If the full length is equal to or |
591 | * greater than @buflen, @buf contains the truncated path with the trailing |
592 | * '\0'. On error, -errno is returned. |
593 | */ |
594 | static inline int kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen) |
595 | { |
596 | return kernfs_path_from_node(root_kn: kn, NULL, buf, buflen); |
597 | } |
598 | |
599 | static inline struct kernfs_node * |
600 | kernfs_find_and_get(struct kernfs_node *kn, const char *name) |
601 | { |
602 | return kernfs_find_and_get_ns(parent: kn, name, NULL); |
603 | } |
604 | |
605 | static inline struct kernfs_node * |
606 | kernfs_walk_and_get(struct kernfs_node *kn, const char *path) |
607 | { |
608 | return kernfs_walk_and_get_ns(parent: kn, path, NULL); |
609 | } |
610 | |
611 | static inline struct kernfs_node * |
612 | kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode, |
613 | void *priv) |
614 | { |
615 | return kernfs_create_dir_ns(parent, name, mode, |
616 | GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, |
617 | priv, NULL); |
618 | } |
619 | |
620 | static inline int kernfs_remove_by_name(struct kernfs_node *parent, |
621 | const char *name) |
622 | { |
623 | return kernfs_remove_by_name_ns(parent, name, NULL); |
624 | } |
625 | |
626 | static inline int kernfs_rename(struct kernfs_node *kn, |
627 | struct kernfs_node *new_parent, |
628 | const char *new_name) |
629 | { |
630 | return kernfs_rename_ns(kn, new_parent, new_name, NULL); |
631 | } |
632 | |
633 | #endif /* __LINUX_KERNFS_H */ |
634 | |