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 | unsigned short flags; |
210 | umode_t mode; |
211 | |
212 | union { |
213 | struct kernfs_elem_dir dir; |
214 | struct kernfs_elem_symlink symlink; |
215 | struct kernfs_elem_attr attr; |
216 | }; |
217 | |
218 | /* |
219 | * 64bit unique ID. On 64bit ino setups, id is the ino. On 32bit, |
220 | * the low 32bits are ino and upper generation. |
221 | */ |
222 | u64 id; |
223 | |
224 | void *priv; |
225 | struct kernfs_iattrs *iattr; |
226 | |
227 | struct rcu_head rcu; |
228 | }; |
229 | |
230 | /* |
231 | * kernfs_syscall_ops may be specified on kernfs_create_root() to support |
232 | * syscalls. These optional callbacks are invoked on the matching syscalls |
233 | * and can perform any kernfs operations which don't necessarily have to be |
234 | * the exact operation requested. An active reference is held for each |
235 | * kernfs_node parameter. |
236 | */ |
237 | struct kernfs_syscall_ops { |
238 | int (*show_options)(struct seq_file *sf, struct kernfs_root *root); |
239 | |
240 | int (*mkdir)(struct kernfs_node *parent, const char *name, |
241 | umode_t mode); |
242 | int (*rmdir)(struct kernfs_node *kn); |
243 | int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent, |
244 | const char *new_name); |
245 | int (*show_path)(struct seq_file *sf, struct kernfs_node *kn, |
246 | struct kernfs_root *root); |
247 | }; |
248 | |
249 | struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root); |
250 | |
251 | struct kernfs_open_file { |
252 | /* published fields */ |
253 | struct kernfs_node *kn; |
254 | struct file *file; |
255 | struct seq_file *seq_file; |
256 | void *priv; |
257 | |
258 | /* private fields, do not use outside kernfs proper */ |
259 | struct mutex mutex; |
260 | struct mutex prealloc_mutex; |
261 | int event; |
262 | struct list_head list; |
263 | char *prealloc_buf; |
264 | |
265 | size_t atomic_write_len; |
266 | bool mmapped:1; |
267 | bool released:1; |
268 | const struct vm_operations_struct *vm_ops; |
269 | }; |
270 | |
271 | struct kernfs_ops { |
272 | /* |
273 | * Optional open/release methods. Both are called with |
274 | * @of->seq_file populated. |
275 | */ |
276 | int (*open)(struct kernfs_open_file *of); |
277 | void (*release)(struct kernfs_open_file *of); |
278 | |
279 | /* |
280 | * Read is handled by either seq_file or raw_read(). |
281 | * |
282 | * If seq_show() is present, seq_file path is active. Other seq |
283 | * operations are optional and if not implemented, the behavior is |
284 | * equivalent to single_open(). @sf->private points to the |
285 | * associated kernfs_open_file. |
286 | * |
287 | * read() is bounced through kernel buffer and a read larger than |
288 | * PAGE_SIZE results in partial operation of PAGE_SIZE. |
289 | */ |
290 | int (*seq_show)(struct seq_file *sf, void *v); |
291 | |
292 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); |
293 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); |
294 | void (*seq_stop)(struct seq_file *sf, void *v); |
295 | |
296 | ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes, |
297 | loff_t off); |
298 | |
299 | /* |
300 | * write() is bounced through kernel buffer. If atomic_write_len |
301 | * is not set, a write larger than PAGE_SIZE results in partial |
302 | * operations of PAGE_SIZE chunks. If atomic_write_len is set, |
303 | * writes upto the specified size are executed atomically but |
304 | * larger ones are rejected with -E2BIG. |
305 | */ |
306 | size_t atomic_write_len; |
307 | /* |
308 | * "prealloc" causes a buffer to be allocated at open for |
309 | * all read/write requests. As ->seq_show uses seq_read() |
310 | * which does its own allocation, it is incompatible with |
311 | * ->prealloc. Provide ->read and ->write with ->prealloc. |
312 | */ |
313 | bool prealloc; |
314 | ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, |
315 | loff_t off); |
316 | |
317 | __poll_t (*poll)(struct kernfs_open_file *of, |
318 | struct poll_table_struct *pt); |
319 | |
320 | int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma); |
321 | loff_t (*llseek)(struct kernfs_open_file *of, loff_t offset, int whence); |
322 | }; |
323 | |
324 | /* |
325 | * The kernfs superblock creation/mount parameter context. |
326 | */ |
327 | struct kernfs_fs_context { |
328 | struct kernfs_root *root; /* Root of the hierarchy being mounted */ |
329 | void *ns_tag; /* Namespace tag of the mount (or NULL) */ |
330 | unsigned long magic; /* File system specific magic number */ |
331 | |
332 | /* The following are set/used by kernfs_mount() */ |
333 | bool new_sb_created; /* Set to T if we allocated a new sb */ |
334 | }; |
335 | |
336 | #ifdef CONFIG_KERNFS |
337 | |
338 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
339 | { |
340 | return kn->flags & KERNFS_TYPE_MASK; |
341 | } |
342 | |
343 | static inline ino_t kernfs_id_ino(u64 id) |
344 | { |
345 | /* id is ino if ino_t is 64bit; otherwise, low 32bits */ |
346 | if (sizeof(ino_t) >= sizeof(u64)) |
347 | return id; |
348 | else |
349 | return (u32)id; |
350 | } |
351 | |
352 | static inline u32 kernfs_id_gen(u64 id) |
353 | { |
354 | /* gen is fixed at 1 if ino_t is 64bit; otherwise, high 32bits */ |
355 | if (sizeof(ino_t) >= sizeof(u64)) |
356 | return 1; |
357 | else |
358 | return id >> 32; |
359 | } |
360 | |
361 | static inline ino_t kernfs_ino(struct kernfs_node *kn) |
362 | { |
363 | return kernfs_id_ino(id: kn->id); |
364 | } |
365 | |
366 | static inline ino_t kernfs_gen(struct kernfs_node *kn) |
367 | { |
368 | return kernfs_id_gen(id: kn->id); |
369 | } |
370 | |
371 | /** |
372 | * kernfs_enable_ns - enable namespace under a directory |
373 | * @kn: directory of interest, should be empty |
374 | * |
375 | * This is to be called right after @kn is created to enable namespace |
376 | * under it. All children of @kn must have non-NULL namespace tags and |
377 | * only the ones which match the super_block's tag will be visible. |
378 | */ |
379 | static inline void kernfs_enable_ns(struct kernfs_node *kn) |
380 | { |
381 | WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR); |
382 | WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children)); |
383 | kn->flags |= KERNFS_NS; |
384 | } |
385 | |
386 | /** |
387 | * kernfs_ns_enabled - test whether namespace is enabled |
388 | * @kn: the node to test |
389 | * |
390 | * Test whether namespace filtering is enabled for the children of @ns. |
391 | */ |
392 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
393 | { |
394 | return kn->flags & KERNFS_NS; |
395 | } |
396 | |
397 | int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen); |
398 | int kernfs_path_from_node(struct kernfs_node *root_kn, struct kernfs_node *kn, |
399 | char *buf, size_t buflen); |
400 | void pr_cont_kernfs_name(struct kernfs_node *kn); |
401 | void pr_cont_kernfs_path(struct kernfs_node *kn); |
402 | struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn); |
403 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
404 | const char *name, const void *ns); |
405 | struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, |
406 | const char *path, const void *ns); |
407 | void kernfs_get(struct kernfs_node *kn); |
408 | void kernfs_put(struct kernfs_node *kn); |
409 | |
410 | struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry); |
411 | struct kernfs_root *kernfs_root_from_sb(struct super_block *sb); |
412 | struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn); |
413 | |
414 | struct dentry *kernfs_node_dentry(struct kernfs_node *kn, |
415 | struct super_block *sb); |
416 | struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, |
417 | unsigned int flags, void *priv); |
418 | void kernfs_destroy_root(struct kernfs_root *root); |
419 | |
420 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
421 | const char *name, umode_t mode, |
422 | kuid_t uid, kgid_t gid, |
423 | void *priv, const void *ns); |
424 | struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, |
425 | const char *name); |
426 | struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, |
427 | const char *name, umode_t mode, |
428 | kuid_t uid, kgid_t gid, |
429 | loff_t size, |
430 | const struct kernfs_ops *ops, |
431 | void *priv, const void *ns, |
432 | struct lock_class_key *key); |
433 | struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, |
434 | const char *name, |
435 | struct kernfs_node *target); |
436 | void kernfs_activate(struct kernfs_node *kn); |
437 | void kernfs_show(struct kernfs_node *kn, bool show); |
438 | void kernfs_remove(struct kernfs_node *kn); |
439 | void kernfs_break_active_protection(struct kernfs_node *kn); |
440 | void kernfs_unbreak_active_protection(struct kernfs_node *kn); |
441 | bool kernfs_remove_self(struct kernfs_node *kn); |
442 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, |
443 | const void *ns); |
444 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
445 | const char *new_name, const void *new_ns); |
446 | int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); |
447 | __poll_t kernfs_generic_poll(struct kernfs_open_file *of, |
448 | struct poll_table_struct *pt); |
449 | void kernfs_notify(struct kernfs_node *kn); |
450 | |
451 | int kernfs_xattr_get(struct kernfs_node *kn, const char *name, |
452 | void *value, size_t size); |
453 | int kernfs_xattr_set(struct kernfs_node *kn, const char *name, |
454 | const void *value, size_t size, int flags); |
455 | |
456 | const void *kernfs_super_ns(struct super_block *sb); |
457 | int kernfs_get_tree(struct fs_context *fc); |
458 | void kernfs_free_fs_context(struct fs_context *fc); |
459 | void kernfs_kill_sb(struct super_block *sb); |
460 | |
461 | void kernfs_init(void); |
462 | |
463 | struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root, |
464 | u64 id); |
465 | #else /* CONFIG_KERNFS */ |
466 | |
467 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
468 | { return 0; } /* whatever */ |
469 | |
470 | static inline void kernfs_enable_ns(struct kernfs_node *kn) { } |
471 | |
472 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
473 | { return false; } |
474 | |
475 | static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) |
476 | { return -ENOSYS; } |
477 | |
478 | static inline int kernfs_path_from_node(struct kernfs_node *root_kn, |
479 | struct kernfs_node *kn, |
480 | char *buf, size_t buflen) |
481 | { return -ENOSYS; } |
482 | |
483 | static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { } |
484 | static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { } |
485 | |
486 | static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) |
487 | { return NULL; } |
488 | |
489 | static inline struct kernfs_node * |
490 | kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, |
491 | const void *ns) |
492 | { return NULL; } |
493 | static inline struct kernfs_node * |
494 | kernfs_walk_and_get_ns(struct kernfs_node *parent, const char *path, |
495 | const void *ns) |
496 | { return NULL; } |
497 | |
498 | static inline void kernfs_get(struct kernfs_node *kn) { } |
499 | static inline void kernfs_put(struct kernfs_node *kn) { } |
500 | |
501 | static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) |
502 | { return NULL; } |
503 | |
504 | static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb) |
505 | { return NULL; } |
506 | |
507 | static inline struct inode * |
508 | kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn) |
509 | { return NULL; } |
510 | |
511 | static inline struct kernfs_root * |
512 | kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags, |
513 | void *priv) |
514 | { return ERR_PTR(-ENOSYS); } |
515 | |
516 | static inline void kernfs_destroy_root(struct kernfs_root *root) { } |
517 | |
518 | static inline struct kernfs_node * |
519 | kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, |
520 | umode_t mode, kuid_t uid, kgid_t gid, |
521 | void *priv, const void *ns) |
522 | { return ERR_PTR(-ENOSYS); } |
523 | |
524 | static inline struct kernfs_node * |
525 | __kernfs_create_file(struct kernfs_node *parent, const char *name, |
526 | umode_t mode, kuid_t uid, kgid_t gid, |
527 | loff_t size, const struct kernfs_ops *ops, |
528 | void *priv, const void *ns, struct lock_class_key *key) |
529 | { return ERR_PTR(-ENOSYS); } |
530 | |
531 | static inline struct kernfs_node * |
532 | kernfs_create_link(struct kernfs_node *parent, const char *name, |
533 | struct kernfs_node *target) |
534 | { return ERR_PTR(-ENOSYS); } |
535 | |
536 | static inline void kernfs_activate(struct kernfs_node *kn) { } |
537 | |
538 | static inline void kernfs_remove(struct kernfs_node *kn) { } |
539 | |
540 | static inline bool kernfs_remove_self(struct kernfs_node *kn) |
541 | { return false; } |
542 | |
543 | static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn, |
544 | const char *name, const void *ns) |
545 | { return -ENOSYS; } |
546 | |
547 | static inline int kernfs_rename_ns(struct kernfs_node *kn, |
548 | struct kernfs_node *new_parent, |
549 | const char *new_name, const void *new_ns) |
550 | { return -ENOSYS; } |
551 | |
552 | static inline int kernfs_setattr(struct kernfs_node *kn, |
553 | const struct iattr *iattr) |
554 | { return -ENOSYS; } |
555 | |
556 | static inline __poll_t kernfs_generic_poll(struct kernfs_open_file *of, |
557 | struct poll_table_struct *pt) |
558 | { return -ENOSYS; } |
559 | |
560 | static inline void kernfs_notify(struct kernfs_node *kn) { } |
561 | |
562 | static inline int kernfs_xattr_get(struct kernfs_node *kn, const char *name, |
563 | void *value, size_t size) |
564 | { return -ENOSYS; } |
565 | |
566 | static inline int kernfs_xattr_set(struct kernfs_node *kn, const char *name, |
567 | const void *value, size_t size, int flags) |
568 | { return -ENOSYS; } |
569 | |
570 | static inline const void *kernfs_super_ns(struct super_block *sb) |
571 | { return NULL; } |
572 | |
573 | static inline int kernfs_get_tree(struct fs_context *fc) |
574 | { return -ENOSYS; } |
575 | |
576 | static inline void kernfs_free_fs_context(struct fs_context *fc) { } |
577 | |
578 | static inline void kernfs_kill_sb(struct super_block *sb) { } |
579 | |
580 | static inline void kernfs_init(void) { } |
581 | |
582 | #endif /* CONFIG_KERNFS */ |
583 | |
584 | /** |
585 | * kernfs_path - build full path of a given node |
586 | * @kn: kernfs_node of interest |
587 | * @buf: buffer to copy @kn's name into |
588 | * @buflen: size of @buf |
589 | * |
590 | * If @kn is NULL result will be "(null)". |
591 | * |
592 | * Returns the length of the full path. If the full length is equal to or |
593 | * greater than @buflen, @buf contains the truncated path with the trailing |
594 | * '\0'. On error, -errno is returned. |
595 | */ |
596 | static inline int kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen) |
597 | { |
598 | return kernfs_path_from_node(root_kn: kn, NULL, buf, buflen); |
599 | } |
600 | |
601 | static inline struct kernfs_node * |
602 | kernfs_find_and_get(struct kernfs_node *kn, const char *name) |
603 | { |
604 | return kernfs_find_and_get_ns(parent: kn, name, NULL); |
605 | } |
606 | |
607 | static inline struct kernfs_node * |
608 | kernfs_walk_and_get(struct kernfs_node *kn, const char *path) |
609 | { |
610 | return kernfs_walk_and_get_ns(parent: kn, path, NULL); |
611 | } |
612 | |
613 | static inline struct kernfs_node * |
614 | kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode, |
615 | void *priv) |
616 | { |
617 | return kernfs_create_dir_ns(parent, name, mode, |
618 | GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, |
619 | priv, NULL); |
620 | } |
621 | |
622 | static inline int kernfs_remove_by_name(struct kernfs_node *parent, |
623 | const char *name) |
624 | { |
625 | return kernfs_remove_by_name_ns(parent, name, NULL); |
626 | } |
627 | |
628 | static inline int kernfs_rename(struct kernfs_node *kn, |
629 | struct kernfs_node *new_parent, |
630 | const char *new_name) |
631 | { |
632 | return kernfs_rename_ns(kn, new_parent, new_name, NULL); |
633 | } |
634 | |
635 | #endif /* __LINUX_KERNFS_H */ |
636 | |