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Commit | Line | Data |
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b8441ed2 TH |
1 | /* |
2 | * fs/kernfs/dir.c - kernfs directory implementation | |
3 | * | |
4 | * Copyright (c) 2001-3 Patrick Mochel | |
5 | * Copyright (c) 2007 SUSE Linux Products GmbH | |
6 | * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org> | |
7 | * | |
8 | * This file is released under the GPLv2. | |
9 | */ | |
fd7b9f7b | 10 | |
abd54f02 | 11 | #include <linux/sched.h> |
fd7b9f7b TH |
12 | #include <linux/fs.h> |
13 | #include <linux/namei.h> | |
14 | #include <linux/idr.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/security.h> | |
17 | #include <linux/hash.h> | |
18 | ||
19 | #include "kernfs-internal.h" | |
20 | ||
a797bfc3 | 21 | DEFINE_MUTEX(kernfs_mutex); |
3eef34ad TH |
22 | static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */ |
23 | static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */ | |
fd7b9f7b | 24 | |
adc5e8b5 | 25 | #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) |
fd7b9f7b | 26 | |
81c173cb TH |
27 | static bool kernfs_active(struct kernfs_node *kn) |
28 | { | |
29 | lockdep_assert_held(&kernfs_mutex); | |
30 | return atomic_read(&kn->active) >= 0; | |
31 | } | |
32 | ||
182fd64b TH |
33 | static bool kernfs_lockdep(struct kernfs_node *kn) |
34 | { | |
35 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
36 | return kn->flags & KERNFS_LOCKDEP; | |
37 | #else | |
38 | return false; | |
39 | #endif | |
40 | } | |
41 | ||
3eef34ad TH |
42 | static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen) |
43 | { | |
17627157 KK |
44 | if (!kn) |
45 | return strlcpy(buf, "(null)", buflen); | |
46 | ||
3eef34ad TH |
47 | return strlcpy(buf, kn->parent ? kn->name : "/", buflen); |
48 | } | |
49 | ||
9f6df573 AK |
50 | /* kernfs_node_depth - compute depth from @from to @to */ |
51 | static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to) | |
3eef34ad | 52 | { |
9f6df573 | 53 | size_t depth = 0; |
3eef34ad | 54 | |
9f6df573 AK |
55 | while (to->parent && to != from) { |
56 | depth++; | |
57 | to = to->parent; | |
58 | } | |
59 | return depth; | |
60 | } | |
3eef34ad | 61 | |
9f6df573 AK |
62 | static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a, |
63 | struct kernfs_node *b) | |
64 | { | |
65 | size_t da, db; | |
66 | struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b); | |
67 | ||
68 | if (ra != rb) | |
69 | return NULL; | |
70 | ||
71 | da = kernfs_depth(ra->kn, a); | |
72 | db = kernfs_depth(rb->kn, b); | |
73 | ||
74 | while (da > db) { | |
75 | a = a->parent; | |
76 | da--; | |
77 | } | |
78 | while (db > da) { | |
79 | b = b->parent; | |
80 | db--; | |
81 | } | |
82 | ||
83 | /* worst case b and a will be the same at root */ | |
84 | while (b != a) { | |
85 | b = b->parent; | |
86 | a = a->parent; | |
87 | } | |
88 | ||
89 | return a; | |
90 | } | |
91 | ||
92 | /** | |
93 | * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to, | |
94 | * where kn_from is treated as root of the path. | |
95 | * @kn_from: kernfs node which should be treated as root for the path | |
96 | * @kn_to: kernfs node to which path is needed | |
97 | * @buf: buffer to copy the path into | |
98 | * @buflen: size of @buf | |
99 | * | |
100 | * We need to handle couple of scenarios here: | |
101 | * [1] when @kn_from is an ancestor of @kn_to at some level | |
102 | * kn_from: /n1/n2/n3 | |
103 | * kn_to: /n1/n2/n3/n4/n5 | |
104 | * result: /n4/n5 | |
105 | * | |
106 | * [2] when @kn_from is on a different hierarchy and we need to find common | |
107 | * ancestor between @kn_from and @kn_to. | |
108 | * kn_from: /n1/n2/n3/n4 | |
109 | * kn_to: /n1/n2/n5 | |
110 | * result: /../../n5 | |
111 | * OR | |
112 | * kn_from: /n1/n2/n3/n4/n5 [depth=5] | |
113 | * kn_to: /n1/n2/n3 [depth=3] | |
114 | * result: /../.. | |
115 | * | |
17627157 KK |
116 | * [3] when @kn_to is NULL result will be "(null)" |
117 | * | |
3abb1d90 TH |
118 | * Returns the length of the full path. If the full length is equal to or |
119 | * greater than @buflen, @buf contains the truncated path with the trailing | |
120 | * '\0'. On error, -errno is returned. | |
9f6df573 AK |
121 | */ |
122 | static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, | |
123 | struct kernfs_node *kn_from, | |
124 | char *buf, size_t buflen) | |
125 | { | |
126 | struct kernfs_node *kn, *common; | |
127 | const char parent_str[] = "/.."; | |
3abb1d90 TH |
128 | size_t depth_from, depth_to, len = 0; |
129 | int i, j; | |
9f6df573 | 130 | |
17627157 KK |
131 | if (!kn_to) |
132 | return strlcpy(buf, "(null)", buflen); | |
133 | ||
9f6df573 AK |
134 | if (!kn_from) |
135 | kn_from = kernfs_root(kn_to)->kn; | |
136 | ||
137 | if (kn_from == kn_to) | |
138 | return strlcpy(buf, "/", buflen); | |
139 | ||
140 | common = kernfs_common_ancestor(kn_from, kn_to); | |
141 | if (WARN_ON(!common)) | |
3abb1d90 | 142 | return -EINVAL; |
9f6df573 AK |
143 | |
144 | depth_to = kernfs_depth(common, kn_to); | |
145 | depth_from = kernfs_depth(common, kn_from); | |
146 | ||
147 | if (buf) | |
148 | buf[0] = '\0'; | |
149 | ||
150 | for (i = 0; i < depth_from; i++) | |
151 | len += strlcpy(buf + len, parent_str, | |
152 | len < buflen ? buflen - len : 0); | |
153 | ||
154 | /* Calculate how many bytes we need for the rest */ | |
3abb1d90 TH |
155 | for (i = depth_to - 1; i >= 0; i--) { |
156 | for (kn = kn_to, j = 0; j < i; j++) | |
157 | kn = kn->parent; | |
158 | len += strlcpy(buf + len, "/", | |
159 | len < buflen ? buflen - len : 0); | |
160 | len += strlcpy(buf + len, kn->name, | |
161 | len < buflen ? buflen - len : 0); | |
9f6df573 | 162 | } |
3eef34ad | 163 | |
3abb1d90 | 164 | return len; |
3eef34ad TH |
165 | } |
166 | ||
167 | /** | |
168 | * kernfs_name - obtain the name of a given node | |
169 | * @kn: kernfs_node of interest | |
170 | * @buf: buffer to copy @kn's name into | |
171 | * @buflen: size of @buf | |
172 | * | |
173 | * Copies the name of @kn into @buf of @buflen bytes. The behavior is | |
174 | * similar to strlcpy(). It returns the length of @kn's name and if @buf | |
175 | * isn't long enough, it's filled upto @buflen-1 and nul terminated. | |
176 | * | |
17627157 KK |
177 | * Fills buffer with "(null)" if @kn is NULL. |
178 | * | |
3eef34ad TH |
179 | * This function can be called from any context. |
180 | */ | |
181 | int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) | |
182 | { | |
183 | unsigned long flags; | |
184 | int ret; | |
185 | ||
186 | spin_lock_irqsave(&kernfs_rename_lock, flags); | |
187 | ret = kernfs_name_locked(kn, buf, buflen); | |
188 | spin_unlock_irqrestore(&kernfs_rename_lock, flags); | |
189 | return ret; | |
190 | } | |
191 | ||
9f6df573 AK |
192 | /** |
193 | * kernfs_path_from_node - build path of node @to relative to @from. | |
194 | * @from: parent kernfs_node relative to which we need to build the path | |
195 | * @to: kernfs_node of interest | |
196 | * @buf: buffer to copy @to's path into | |
197 | * @buflen: size of @buf | |
198 | * | |
199 | * Builds @to's path relative to @from in @buf. @from and @to must | |
200 | * be on the same kernfs-root. If @from is not parent of @to, then a relative | |
201 | * path (which includes '..'s) as needed to reach from @from to @to is | |
202 | * returned. | |
203 | * | |
3abb1d90 TH |
204 | * Returns the length of the full path. If the full length is equal to or |
205 | * greater than @buflen, @buf contains the truncated path with the trailing | |
206 | * '\0'. On error, -errno is returned. | |
9f6df573 AK |
207 | */ |
208 | int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from, | |
209 | char *buf, size_t buflen) | |
210 | { | |
211 | unsigned long flags; | |
212 | int ret; | |
213 | ||
214 | spin_lock_irqsave(&kernfs_rename_lock, flags); | |
215 | ret = kernfs_path_from_node_locked(to, from, buf, buflen); | |
216 | spin_unlock_irqrestore(&kernfs_rename_lock, flags); | |
217 | return ret; | |
218 | } | |
219 | EXPORT_SYMBOL_GPL(kernfs_path_from_node); | |
220 | ||
3eef34ad TH |
221 | /** |
222 | * pr_cont_kernfs_name - pr_cont name of a kernfs_node | |
223 | * @kn: kernfs_node of interest | |
224 | * | |
225 | * This function can be called from any context. | |
226 | */ | |
227 | void pr_cont_kernfs_name(struct kernfs_node *kn) | |
228 | { | |
229 | unsigned long flags; | |
230 | ||
231 | spin_lock_irqsave(&kernfs_rename_lock, flags); | |
232 | ||
233 | kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf)); | |
234 | pr_cont("%s", kernfs_pr_cont_buf); | |
235 | ||
236 | spin_unlock_irqrestore(&kernfs_rename_lock, flags); | |
237 | } | |
238 | ||
239 | /** | |
240 | * pr_cont_kernfs_path - pr_cont path of a kernfs_node | |
241 | * @kn: kernfs_node of interest | |
242 | * | |
243 | * This function can be called from any context. | |
244 | */ | |
245 | void pr_cont_kernfs_path(struct kernfs_node *kn) | |
246 | { | |
247 | unsigned long flags; | |
9f6df573 | 248 | int sz; |
3eef34ad TH |
249 | |
250 | spin_lock_irqsave(&kernfs_rename_lock, flags); | |
251 | ||
9f6df573 AK |
252 | sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf, |
253 | sizeof(kernfs_pr_cont_buf)); | |
254 | if (sz < 0) { | |
255 | pr_cont("(error)"); | |
256 | goto out; | |
257 | } | |
258 | ||
259 | if (sz >= sizeof(kernfs_pr_cont_buf)) { | |
260 | pr_cont("(name too long)"); | |
261 | goto out; | |
262 | } | |
263 | ||
264 | pr_cont("%s", kernfs_pr_cont_buf); | |
3eef34ad | 265 | |
9f6df573 | 266 | out: |
3eef34ad TH |
267 | spin_unlock_irqrestore(&kernfs_rename_lock, flags); |
268 | } | |
269 | ||
270 | /** | |
271 | * kernfs_get_parent - determine the parent node and pin it | |
272 | * @kn: kernfs_node of interest | |
273 | * | |
274 | * Determines @kn's parent, pins and returns it. This function can be | |
275 | * called from any context. | |
276 | */ | |
277 | struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) | |
278 | { | |
279 | struct kernfs_node *parent; | |
280 | unsigned long flags; | |
281 | ||
282 | spin_lock_irqsave(&kernfs_rename_lock, flags); | |
283 | parent = kn->parent; | |
284 | kernfs_get(parent); | |
285 | spin_unlock_irqrestore(&kernfs_rename_lock, flags); | |
286 | ||
287 | return parent; | |
288 | } | |
289 | ||
fd7b9f7b | 290 | /** |
c637b8ac | 291 | * kernfs_name_hash |
fd7b9f7b TH |
292 | * @name: Null terminated string to hash |
293 | * @ns: Namespace tag to hash | |
294 | * | |
295 | * Returns 31 bit hash of ns + name (so it fits in an off_t ) | |
296 | */ | |
c637b8ac | 297 | static unsigned int kernfs_name_hash(const char *name, const void *ns) |
fd7b9f7b | 298 | { |
8387ff25 | 299 | unsigned long hash = init_name_hash(ns); |
fd7b9f7b TH |
300 | unsigned int len = strlen(name); |
301 | while (len--) | |
302 | hash = partial_name_hash(*name++, hash); | |
8387ff25 | 303 | hash = end_name_hash(hash); |
fd7b9f7b TH |
304 | hash &= 0x7fffffffU; |
305 | /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ | |
88391d49 | 306 | if (hash < 2) |
fd7b9f7b TH |
307 | hash += 2; |
308 | if (hash >= INT_MAX) | |
309 | hash = INT_MAX - 1; | |
310 | return hash; | |
311 | } | |
312 | ||
c637b8ac TH |
313 | static int kernfs_name_compare(unsigned int hash, const char *name, |
314 | const void *ns, const struct kernfs_node *kn) | |
fd7b9f7b | 315 | { |
72392ed0 RV |
316 | if (hash < kn->hash) |
317 | return -1; | |
318 | if (hash > kn->hash) | |
319 | return 1; | |
320 | if (ns < kn->ns) | |
321 | return -1; | |
322 | if (ns > kn->ns) | |
323 | return 1; | |
adc5e8b5 | 324 | return strcmp(name, kn->name); |
fd7b9f7b TH |
325 | } |
326 | ||
c637b8ac TH |
327 | static int kernfs_sd_compare(const struct kernfs_node *left, |
328 | const struct kernfs_node *right) | |
fd7b9f7b | 329 | { |
c637b8ac | 330 | return kernfs_name_compare(left->hash, left->name, left->ns, right); |
fd7b9f7b TH |
331 | } |
332 | ||
333 | /** | |
c637b8ac | 334 | * kernfs_link_sibling - link kernfs_node into sibling rbtree |
324a56e1 | 335 | * @kn: kernfs_node of interest |
fd7b9f7b | 336 | * |
324a56e1 | 337 | * Link @kn into its sibling rbtree which starts from |
adc5e8b5 | 338 | * @kn->parent->dir.children. |
fd7b9f7b TH |
339 | * |
340 | * Locking: | |
a797bfc3 | 341 | * mutex_lock(kernfs_mutex) |
fd7b9f7b TH |
342 | * |
343 | * RETURNS: | |
344 | * 0 on susccess -EEXIST on failure. | |
345 | */ | |
c637b8ac | 346 | static int kernfs_link_sibling(struct kernfs_node *kn) |
fd7b9f7b | 347 | { |
adc5e8b5 | 348 | struct rb_node **node = &kn->parent->dir.children.rb_node; |
fd7b9f7b TH |
349 | struct rb_node *parent = NULL; |
350 | ||
fd7b9f7b | 351 | while (*node) { |
324a56e1 | 352 | struct kernfs_node *pos; |
fd7b9f7b TH |
353 | int result; |
354 | ||
324a56e1 | 355 | pos = rb_to_kn(*node); |
fd7b9f7b | 356 | parent = *node; |
c637b8ac | 357 | result = kernfs_sd_compare(kn, pos); |
fd7b9f7b | 358 | if (result < 0) |
adc5e8b5 | 359 | node = &pos->rb.rb_left; |
fd7b9f7b | 360 | else if (result > 0) |
adc5e8b5 | 361 | node = &pos->rb.rb_right; |
fd7b9f7b TH |
362 | else |
363 | return -EEXIST; | |
364 | } | |
c1befb88 | 365 | |
fd7b9f7b | 366 | /* add new node and rebalance the tree */ |
adc5e8b5 TH |
367 | rb_link_node(&kn->rb, parent, node); |
368 | rb_insert_color(&kn->rb, &kn->parent->dir.children); | |
c1befb88 JZ |
369 | |
370 | /* successfully added, account subdir number */ | |
371 | if (kernfs_type(kn) == KERNFS_DIR) | |
372 | kn->parent->dir.subdirs++; | |
373 | ||
fd7b9f7b TH |
374 | return 0; |
375 | } | |
376 | ||
377 | /** | |
c637b8ac | 378 | * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree |
324a56e1 | 379 | * @kn: kernfs_node of interest |
fd7b9f7b | 380 | * |
35beab06 TH |
381 | * Try to unlink @kn from its sibling rbtree which starts from |
382 | * kn->parent->dir.children. Returns %true if @kn was actually | |
383 | * removed, %false if @kn wasn't on the rbtree. | |
fd7b9f7b TH |
384 | * |
385 | * Locking: | |
a797bfc3 | 386 | * mutex_lock(kernfs_mutex) |
fd7b9f7b | 387 | */ |
35beab06 | 388 | static bool kernfs_unlink_sibling(struct kernfs_node *kn) |
fd7b9f7b | 389 | { |
35beab06 TH |
390 | if (RB_EMPTY_NODE(&kn->rb)) |
391 | return false; | |
392 | ||
df23fc39 | 393 | if (kernfs_type(kn) == KERNFS_DIR) |
adc5e8b5 | 394 | kn->parent->dir.subdirs--; |
fd7b9f7b | 395 | |
adc5e8b5 | 396 | rb_erase(&kn->rb, &kn->parent->dir.children); |
35beab06 TH |
397 | RB_CLEAR_NODE(&kn->rb); |
398 | return true; | |
fd7b9f7b TH |
399 | } |
400 | ||
401 | /** | |
c637b8ac | 402 | * kernfs_get_active - get an active reference to kernfs_node |
324a56e1 | 403 | * @kn: kernfs_node to get an active reference to |
fd7b9f7b | 404 | * |
324a56e1 | 405 | * Get an active reference of @kn. This function is noop if @kn |
fd7b9f7b TH |
406 | * is NULL. |
407 | * | |
408 | * RETURNS: | |
324a56e1 | 409 | * Pointer to @kn on success, NULL on failure. |
fd7b9f7b | 410 | */ |
c637b8ac | 411 | struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) |
fd7b9f7b | 412 | { |
324a56e1 | 413 | if (unlikely(!kn)) |
fd7b9f7b TH |
414 | return NULL; |
415 | ||
f4b3e631 GKH |
416 | if (!atomic_inc_unless_negative(&kn->active)) |
417 | return NULL; | |
895a068a | 418 | |
182fd64b | 419 | if (kernfs_lockdep(kn)) |
f4b3e631 GKH |
420 | rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); |
421 | return kn; | |
fd7b9f7b TH |
422 | } |
423 | ||
424 | /** | |
c637b8ac | 425 | * kernfs_put_active - put an active reference to kernfs_node |
324a56e1 | 426 | * @kn: kernfs_node to put an active reference to |
fd7b9f7b | 427 | * |
324a56e1 | 428 | * Put an active reference to @kn. This function is noop if @kn |
fd7b9f7b TH |
429 | * is NULL. |
430 | */ | |
c637b8ac | 431 | void kernfs_put_active(struct kernfs_node *kn) |
fd7b9f7b | 432 | { |
abd54f02 | 433 | struct kernfs_root *root = kernfs_root(kn); |
fd7b9f7b TH |
434 | int v; |
435 | ||
324a56e1 | 436 | if (unlikely(!kn)) |
fd7b9f7b TH |
437 | return; |
438 | ||
182fd64b | 439 | if (kernfs_lockdep(kn)) |
324a56e1 | 440 | rwsem_release(&kn->dep_map, 1, _RET_IP_); |
adc5e8b5 | 441 | v = atomic_dec_return(&kn->active); |
df23fc39 | 442 | if (likely(v != KN_DEACTIVATED_BIAS)) |
fd7b9f7b TH |
443 | return; |
444 | ||
abd54f02 | 445 | wake_up_all(&root->deactivate_waitq); |
fd7b9f7b TH |
446 | } |
447 | ||
448 | /** | |
81c173cb TH |
449 | * kernfs_drain - drain kernfs_node |
450 | * @kn: kernfs_node to drain | |
fd7b9f7b | 451 | * |
81c173cb TH |
452 | * Drain existing usages and nuke all existing mmaps of @kn. Mutiple |
453 | * removers may invoke this function concurrently on @kn and all will | |
454 | * return after draining is complete. | |
fd7b9f7b | 455 | */ |
81c173cb | 456 | static void kernfs_drain(struct kernfs_node *kn) |
35beab06 | 457 | __releases(&kernfs_mutex) __acquires(&kernfs_mutex) |
fd7b9f7b | 458 | { |
abd54f02 | 459 | struct kernfs_root *root = kernfs_root(kn); |
fd7b9f7b | 460 | |
35beab06 | 461 | lockdep_assert_held(&kernfs_mutex); |
81c173cb | 462 | WARN_ON_ONCE(kernfs_active(kn)); |
ea1c472d | 463 | |
35beab06 | 464 | mutex_unlock(&kernfs_mutex); |
abd54f02 | 465 | |
182fd64b | 466 | if (kernfs_lockdep(kn)) { |
35beab06 TH |
467 | rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); |
468 | if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) | |
469 | lock_contended(&kn->dep_map, _RET_IP_); | |
470 | } | |
abd54f02 | 471 | |
35beab06 | 472 | /* but everyone should wait for draining */ |
abd54f02 TH |
473 | wait_event(root->deactivate_waitq, |
474 | atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); | |
fd7b9f7b | 475 | |
182fd64b | 476 | if (kernfs_lockdep(kn)) { |
a6607930 TH |
477 | lock_acquired(&kn->dep_map, _RET_IP_); |
478 | rwsem_release(&kn->dep_map, 1, _RET_IP_); | |
479 | } | |
35beab06 | 480 | |
0e67db2f | 481 | kernfs_drain_open_files(kn); |
ccf02aaf | 482 | |
35beab06 | 483 | mutex_lock(&kernfs_mutex); |
fd7b9f7b TH |
484 | } |
485 | ||
fd7b9f7b | 486 | /** |
324a56e1 TH |
487 | * kernfs_get - get a reference count on a kernfs_node |
488 | * @kn: the target kernfs_node | |
fd7b9f7b | 489 | */ |
324a56e1 | 490 | void kernfs_get(struct kernfs_node *kn) |
fd7b9f7b | 491 | { |
324a56e1 | 492 | if (kn) { |
adc5e8b5 TH |
493 | WARN_ON(!atomic_read(&kn->count)); |
494 | atomic_inc(&kn->count); | |
fd7b9f7b TH |
495 | } |
496 | } | |
497 | EXPORT_SYMBOL_GPL(kernfs_get); | |
498 | ||
499 | /** | |
324a56e1 TH |
500 | * kernfs_put - put a reference count on a kernfs_node |
501 | * @kn: the target kernfs_node | |
fd7b9f7b | 502 | * |
324a56e1 | 503 | * Put a reference count of @kn and destroy it if it reached zero. |
fd7b9f7b | 504 | */ |
324a56e1 | 505 | void kernfs_put(struct kernfs_node *kn) |
fd7b9f7b | 506 | { |
324a56e1 | 507 | struct kernfs_node *parent; |
ba7443bc | 508 | struct kernfs_root *root; |
fd7b9f7b | 509 | |
adc5e8b5 | 510 | if (!kn || !atomic_dec_and_test(&kn->count)) |
fd7b9f7b | 511 | return; |
324a56e1 | 512 | root = kernfs_root(kn); |
fd7b9f7b | 513 | repeat: |
81c173cb TH |
514 | /* |
515 | * Moving/renaming is always done while holding reference. | |
adc5e8b5 | 516 | * kn->parent won't change beneath us. |
fd7b9f7b | 517 | */ |
adc5e8b5 | 518 | parent = kn->parent; |
fd7b9f7b | 519 | |
81c173cb TH |
520 | WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, |
521 | "kernfs_put: %s/%s: released with incorrect active_ref %d\n", | |
522 | parent ? parent->name : "", kn->name, atomic_read(&kn->active)); | |
324a56e1 | 523 | |
df23fc39 | 524 | if (kernfs_type(kn) == KERNFS_LINK) |
adc5e8b5 | 525 | kernfs_put(kn->symlink.target_kn); |
dfeb0750 TH |
526 | |
527 | kfree_const(kn->name); | |
528 | ||
adc5e8b5 TH |
529 | if (kn->iattr) { |
530 | if (kn->iattr->ia_secdata) | |
531 | security_release_secctx(kn->iattr->ia_secdata, | |
532 | kn->iattr->ia_secdata_len); | |
533 | simple_xattrs_free(&kn->iattr->xattrs); | |
2322392b | 534 | } |
adc5e8b5 TH |
535 | kfree(kn->iattr); |
536 | ida_simple_remove(&root->ino_ida, kn->ino); | |
a797bfc3 | 537 | kmem_cache_free(kernfs_node_cache, kn); |
fd7b9f7b | 538 | |
324a56e1 TH |
539 | kn = parent; |
540 | if (kn) { | |
adc5e8b5 | 541 | if (atomic_dec_and_test(&kn->count)) |
ba7443bc TH |
542 | goto repeat; |
543 | } else { | |
324a56e1 | 544 | /* just released the root kn, free @root too */ |
bc755553 | 545 | ida_destroy(&root->ino_ida); |
ba7443bc TH |
546 | kfree(root); |
547 | } | |
fd7b9f7b TH |
548 | } |
549 | EXPORT_SYMBOL_GPL(kernfs_put); | |
550 | ||
c637b8ac | 551 | static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) |
fd7b9f7b | 552 | { |
324a56e1 | 553 | struct kernfs_node *kn; |
fd7b9f7b TH |
554 | |
555 | if (flags & LOOKUP_RCU) | |
556 | return -ECHILD; | |
557 | ||
19bbb926 | 558 | /* Always perform fresh lookup for negatives */ |
2b0143b5 | 559 | if (d_really_is_negative(dentry)) |
19bbb926 TH |
560 | goto out_bad_unlocked; |
561 | ||
324a56e1 | 562 | kn = dentry->d_fsdata; |
a797bfc3 | 563 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 564 | |
81c173cb TH |
565 | /* The kernfs node has been deactivated */ |
566 | if (!kernfs_active(kn)) | |
fd7b9f7b TH |
567 | goto out_bad; |
568 | ||
c637b8ac | 569 | /* The kernfs node has been moved? */ |
adc5e8b5 | 570 | if (dentry->d_parent->d_fsdata != kn->parent) |
fd7b9f7b TH |
571 | goto out_bad; |
572 | ||
c637b8ac | 573 | /* The kernfs node has been renamed */ |
adc5e8b5 | 574 | if (strcmp(dentry->d_name.name, kn->name) != 0) |
fd7b9f7b TH |
575 | goto out_bad; |
576 | ||
c637b8ac | 577 | /* The kernfs node has been moved to a different namespace */ |
adc5e8b5 | 578 | if (kn->parent && kernfs_ns_enabled(kn->parent) && |
c525aadd | 579 | kernfs_info(dentry->d_sb)->ns != kn->ns) |
fd7b9f7b TH |
580 | goto out_bad; |
581 | ||
a797bfc3 | 582 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
583 | return 1; |
584 | out_bad: | |
a797bfc3 | 585 | mutex_unlock(&kernfs_mutex); |
19bbb926 | 586 | out_bad_unlocked: |
fd7b9f7b TH |
587 | return 0; |
588 | } | |
589 | ||
c637b8ac | 590 | static void kernfs_dop_release(struct dentry *dentry) |
fd7b9f7b TH |
591 | { |
592 | kernfs_put(dentry->d_fsdata); | |
593 | } | |
594 | ||
a797bfc3 | 595 | const struct dentry_operations kernfs_dops = { |
c637b8ac | 596 | .d_revalidate = kernfs_dop_revalidate, |
c637b8ac | 597 | .d_release = kernfs_dop_release, |
fd7b9f7b TH |
598 | }; |
599 | ||
0c23b225 TH |
600 | /** |
601 | * kernfs_node_from_dentry - determine kernfs_node associated with a dentry | |
602 | * @dentry: the dentry in question | |
603 | * | |
604 | * Return the kernfs_node associated with @dentry. If @dentry is not a | |
605 | * kernfs one, %NULL is returned. | |
606 | * | |
607 | * While the returned kernfs_node will stay accessible as long as @dentry | |
608 | * is accessible, the returned node can be in any state and the caller is | |
609 | * fully responsible for determining what's accessible. | |
610 | */ | |
611 | struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) | |
612 | { | |
f41c5934 | 613 | if (dentry->d_sb->s_op == &kernfs_sops) |
0c23b225 TH |
614 | return dentry->d_fsdata; |
615 | return NULL; | |
616 | } | |
617 | ||
db4aad20 TH |
618 | static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, |
619 | const char *name, umode_t mode, | |
620 | unsigned flags) | |
fd7b9f7b | 621 | { |
324a56e1 | 622 | struct kernfs_node *kn; |
bc755553 | 623 | int ret; |
fd7b9f7b | 624 | |
dfeb0750 TH |
625 | name = kstrdup_const(name, GFP_KERNEL); |
626 | if (!name) | |
627 | return NULL; | |
fd7b9f7b | 628 | |
a797bfc3 | 629 | kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); |
324a56e1 | 630 | if (!kn) |
fd7b9f7b TH |
631 | goto err_out1; |
632 | ||
b2a209ff | 633 | ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL); |
bc755553 | 634 | if (ret < 0) |
fd7b9f7b | 635 | goto err_out2; |
adc5e8b5 | 636 | kn->ino = ret; |
fd7b9f7b | 637 | |
adc5e8b5 | 638 | atomic_set(&kn->count, 1); |
81c173cb | 639 | atomic_set(&kn->active, KN_DEACTIVATED_BIAS); |
35beab06 | 640 | RB_CLEAR_NODE(&kn->rb); |
fd7b9f7b | 641 | |
adc5e8b5 TH |
642 | kn->name = name; |
643 | kn->mode = mode; | |
81c173cb | 644 | kn->flags = flags; |
fd7b9f7b | 645 | |
324a56e1 | 646 | return kn; |
fd7b9f7b TH |
647 | |
648 | err_out2: | |
a797bfc3 | 649 | kmem_cache_free(kernfs_node_cache, kn); |
fd7b9f7b | 650 | err_out1: |
dfeb0750 | 651 | kfree_const(name); |
fd7b9f7b TH |
652 | return NULL; |
653 | } | |
654 | ||
db4aad20 TH |
655 | struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, |
656 | const char *name, umode_t mode, | |
657 | unsigned flags) | |
658 | { | |
659 | struct kernfs_node *kn; | |
660 | ||
661 | kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags); | |
662 | if (kn) { | |
663 | kernfs_get(parent); | |
664 | kn->parent = parent; | |
665 | } | |
666 | return kn; | |
667 | } | |
668 | ||
fd7b9f7b | 669 | /** |
c637b8ac | 670 | * kernfs_add_one - add kernfs_node to parent without warning |
324a56e1 | 671 | * @kn: kernfs_node to be added |
fd7b9f7b | 672 | * |
db4aad20 TH |
673 | * The caller must already have initialized @kn->parent. This |
674 | * function increments nlink of the parent's inode if @kn is a | |
675 | * directory and link into the children list of the parent. | |
fd7b9f7b | 676 | * |
fd7b9f7b TH |
677 | * RETURNS: |
678 | * 0 on success, -EEXIST if entry with the given name already | |
679 | * exists. | |
680 | */ | |
988cd7af | 681 | int kernfs_add_one(struct kernfs_node *kn) |
fd7b9f7b | 682 | { |
db4aad20 | 683 | struct kernfs_node *parent = kn->parent; |
c525aadd | 684 | struct kernfs_iattrs *ps_iattr; |
988cd7af | 685 | bool has_ns; |
fd7b9f7b TH |
686 | int ret; |
687 | ||
988cd7af TH |
688 | mutex_lock(&kernfs_mutex); |
689 | ||
690 | ret = -EINVAL; | |
691 | has_ns = kernfs_ns_enabled(parent); | |
692 | if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", | |
693 | has_ns ? "required" : "invalid", parent->name, kn->name)) | |
694 | goto out_unlock; | |
fd7b9f7b | 695 | |
df23fc39 | 696 | if (kernfs_type(parent) != KERNFS_DIR) |
988cd7af | 697 | goto out_unlock; |
fd7b9f7b | 698 | |
988cd7af | 699 | ret = -ENOENT; |
ea015218 EB |
700 | if (parent->flags & KERNFS_EMPTY_DIR) |
701 | goto out_unlock; | |
702 | ||
d35258ef | 703 | if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) |
988cd7af | 704 | goto out_unlock; |
798c75a0 | 705 | |
c637b8ac | 706 | kn->hash = kernfs_name_hash(kn->name, kn->ns); |
fd7b9f7b | 707 | |
c637b8ac | 708 | ret = kernfs_link_sibling(kn); |
fd7b9f7b | 709 | if (ret) |
988cd7af | 710 | goto out_unlock; |
fd7b9f7b TH |
711 | |
712 | /* Update timestamps on the parent */ | |
adc5e8b5 | 713 | ps_iattr = parent->iattr; |
fd7b9f7b TH |
714 | if (ps_iattr) { |
715 | struct iattr *ps_iattrs = &ps_iattr->ia_iattr; | |
3a3a5fec DD |
716 | ktime_get_real_ts(&ps_iattrs->ia_ctime); |
717 | ps_iattrs->ia_mtime = ps_iattrs->ia_ctime; | |
fd7b9f7b TH |
718 | } |
719 | ||
d35258ef TH |
720 | mutex_unlock(&kernfs_mutex); |
721 | ||
722 | /* | |
723 | * Activate the new node unless CREATE_DEACTIVATED is requested. | |
724 | * If not activated here, the kernfs user is responsible for | |
725 | * activating the node with kernfs_activate(). A node which hasn't | |
726 | * been activated is not visible to userland and its removal won't | |
727 | * trigger deactivation. | |
728 | */ | |
729 | if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) | |
730 | kernfs_activate(kn); | |
731 | return 0; | |
732 | ||
988cd7af | 733 | out_unlock: |
a797bfc3 | 734 | mutex_unlock(&kernfs_mutex); |
988cd7af | 735 | return ret; |
fd7b9f7b TH |
736 | } |
737 | ||
738 | /** | |
324a56e1 TH |
739 | * kernfs_find_ns - find kernfs_node with the given name |
740 | * @parent: kernfs_node to search under | |
fd7b9f7b TH |
741 | * @name: name to look for |
742 | * @ns: the namespace tag to use | |
743 | * | |
324a56e1 TH |
744 | * Look for kernfs_node with name @name under @parent. Returns pointer to |
745 | * the found kernfs_node on success, %NULL on failure. | |
fd7b9f7b | 746 | */ |
324a56e1 TH |
747 | static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, |
748 | const unsigned char *name, | |
749 | const void *ns) | |
fd7b9f7b | 750 | { |
adc5e8b5 | 751 | struct rb_node *node = parent->dir.children.rb_node; |
ac9bba03 | 752 | bool has_ns = kernfs_ns_enabled(parent); |
fd7b9f7b TH |
753 | unsigned int hash; |
754 | ||
a797bfc3 | 755 | lockdep_assert_held(&kernfs_mutex); |
fd7b9f7b TH |
756 | |
757 | if (has_ns != (bool)ns) { | |
c637b8ac | 758 | WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", |
adc5e8b5 | 759 | has_ns ? "required" : "invalid", parent->name, name); |
fd7b9f7b TH |
760 | return NULL; |
761 | } | |
762 | ||
c637b8ac | 763 | hash = kernfs_name_hash(name, ns); |
fd7b9f7b | 764 | while (node) { |
324a56e1 | 765 | struct kernfs_node *kn; |
fd7b9f7b TH |
766 | int result; |
767 | ||
324a56e1 | 768 | kn = rb_to_kn(node); |
c637b8ac | 769 | result = kernfs_name_compare(hash, name, ns, kn); |
fd7b9f7b TH |
770 | if (result < 0) |
771 | node = node->rb_left; | |
772 | else if (result > 0) | |
773 | node = node->rb_right; | |
774 | else | |
324a56e1 | 775 | return kn; |
fd7b9f7b TH |
776 | } |
777 | return NULL; | |
778 | } | |
779 | ||
bd96f76a TH |
780 | static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, |
781 | const unsigned char *path, | |
782 | const void *ns) | |
783 | { | |
e56ed358 TH |
784 | size_t len; |
785 | char *p, *name; | |
bd96f76a TH |
786 | |
787 | lockdep_assert_held(&kernfs_mutex); | |
788 | ||
e56ed358 TH |
789 | /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */ |
790 | spin_lock_irq(&kernfs_rename_lock); | |
791 | ||
792 | len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf)); | |
793 | ||
794 | if (len >= sizeof(kernfs_pr_cont_buf)) { | |
795 | spin_unlock_irq(&kernfs_rename_lock); | |
bd96f76a | 796 | return NULL; |
e56ed358 TH |
797 | } |
798 | ||
799 | p = kernfs_pr_cont_buf; | |
bd96f76a TH |
800 | |
801 | while ((name = strsep(&p, "/")) && parent) { | |
802 | if (*name == '\0') | |
803 | continue; | |
804 | parent = kernfs_find_ns(parent, name, ns); | |
805 | } | |
806 | ||
e56ed358 TH |
807 | spin_unlock_irq(&kernfs_rename_lock); |
808 | ||
bd96f76a TH |
809 | return parent; |
810 | } | |
811 | ||
fd7b9f7b | 812 | /** |
324a56e1 TH |
813 | * kernfs_find_and_get_ns - find and get kernfs_node with the given name |
814 | * @parent: kernfs_node to search under | |
fd7b9f7b TH |
815 | * @name: name to look for |
816 | * @ns: the namespace tag to use | |
817 | * | |
324a56e1 | 818 | * Look for kernfs_node with name @name under @parent and get a reference |
fd7b9f7b | 819 | * if found. This function may sleep and returns pointer to the found |
324a56e1 | 820 | * kernfs_node on success, %NULL on failure. |
fd7b9f7b | 821 | */ |
324a56e1 TH |
822 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
823 | const char *name, const void *ns) | |
fd7b9f7b | 824 | { |
324a56e1 | 825 | struct kernfs_node *kn; |
fd7b9f7b | 826 | |
a797bfc3 | 827 | mutex_lock(&kernfs_mutex); |
324a56e1 TH |
828 | kn = kernfs_find_ns(parent, name, ns); |
829 | kernfs_get(kn); | |
a797bfc3 | 830 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b | 831 | |
324a56e1 | 832 | return kn; |
fd7b9f7b TH |
833 | } |
834 | EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); | |
835 | ||
bd96f76a TH |
836 | /** |
837 | * kernfs_walk_and_get_ns - find and get kernfs_node with the given path | |
838 | * @parent: kernfs_node to search under | |
839 | * @path: path to look for | |
840 | * @ns: the namespace tag to use | |
841 | * | |
842 | * Look for kernfs_node with path @path under @parent and get a reference | |
843 | * if found. This function may sleep and returns pointer to the found | |
844 | * kernfs_node on success, %NULL on failure. | |
845 | */ | |
846 | struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, | |
847 | const char *path, const void *ns) | |
848 | { | |
849 | struct kernfs_node *kn; | |
850 | ||
851 | mutex_lock(&kernfs_mutex); | |
852 | kn = kernfs_walk_ns(parent, path, ns); | |
853 | kernfs_get(kn); | |
854 | mutex_unlock(&kernfs_mutex); | |
855 | ||
856 | return kn; | |
857 | } | |
858 | ||
ba7443bc TH |
859 | /** |
860 | * kernfs_create_root - create a new kernfs hierarchy | |
90c07c89 | 861 | * @scops: optional syscall operations for the hierarchy |
d35258ef | 862 | * @flags: KERNFS_ROOT_* flags |
ba7443bc TH |
863 | * @priv: opaque data associated with the new directory |
864 | * | |
865 | * Returns the root of the new hierarchy on success, ERR_PTR() value on | |
866 | * failure. | |
867 | */ | |
90c07c89 | 868 | struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, |
d35258ef | 869 | unsigned int flags, void *priv) |
ba7443bc TH |
870 | { |
871 | struct kernfs_root *root; | |
324a56e1 | 872 | struct kernfs_node *kn; |
ba7443bc TH |
873 | |
874 | root = kzalloc(sizeof(*root), GFP_KERNEL); | |
875 | if (!root) | |
876 | return ERR_PTR(-ENOMEM); | |
877 | ||
bc755553 | 878 | ida_init(&root->ino_ida); |
7d568a83 | 879 | INIT_LIST_HEAD(&root->supers); |
bc755553 | 880 | |
db4aad20 TH |
881 | kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, |
882 | KERNFS_DIR); | |
324a56e1 | 883 | if (!kn) { |
bc755553 | 884 | ida_destroy(&root->ino_ida); |
ba7443bc TH |
885 | kfree(root); |
886 | return ERR_PTR(-ENOMEM); | |
887 | } | |
888 | ||
324a56e1 | 889 | kn->priv = priv; |
adc5e8b5 | 890 | kn->dir.root = root; |
ba7443bc | 891 | |
90c07c89 | 892 | root->syscall_ops = scops; |
d35258ef | 893 | root->flags = flags; |
324a56e1 | 894 | root->kn = kn; |
abd54f02 | 895 | init_waitqueue_head(&root->deactivate_waitq); |
ba7443bc | 896 | |
d35258ef TH |
897 | if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) |
898 | kernfs_activate(kn); | |
899 | ||
ba7443bc TH |
900 | return root; |
901 | } | |
902 | ||
903 | /** | |
904 | * kernfs_destroy_root - destroy a kernfs hierarchy | |
905 | * @root: root of the hierarchy to destroy | |
906 | * | |
907 | * Destroy the hierarchy anchored at @root by removing all existing | |
908 | * directories and destroying @root. | |
909 | */ | |
910 | void kernfs_destroy_root(struct kernfs_root *root) | |
911 | { | |
324a56e1 | 912 | kernfs_remove(root->kn); /* will also free @root */ |
ba7443bc TH |
913 | } |
914 | ||
fd7b9f7b TH |
915 | /** |
916 | * kernfs_create_dir_ns - create a directory | |
917 | * @parent: parent in which to create a new directory | |
918 | * @name: name of the new directory | |
bb8b9d09 | 919 | * @mode: mode of the new directory |
fd7b9f7b TH |
920 | * @priv: opaque data associated with the new directory |
921 | * @ns: optional namespace tag of the directory | |
922 | * | |
923 | * Returns the created node on success, ERR_PTR() value on failure. | |
924 | */ | |
324a56e1 | 925 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
bb8b9d09 TH |
926 | const char *name, umode_t mode, |
927 | void *priv, const void *ns) | |
fd7b9f7b | 928 | { |
324a56e1 | 929 | struct kernfs_node *kn; |
fd7b9f7b TH |
930 | int rc; |
931 | ||
932 | /* allocate */ | |
db4aad20 | 933 | kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR); |
324a56e1 | 934 | if (!kn) |
fd7b9f7b TH |
935 | return ERR_PTR(-ENOMEM); |
936 | ||
adc5e8b5 TH |
937 | kn->dir.root = parent->dir.root; |
938 | kn->ns = ns; | |
324a56e1 | 939 | kn->priv = priv; |
fd7b9f7b TH |
940 | |
941 | /* link in */ | |
988cd7af | 942 | rc = kernfs_add_one(kn); |
fd7b9f7b | 943 | if (!rc) |
324a56e1 | 944 | return kn; |
fd7b9f7b | 945 | |
324a56e1 | 946 | kernfs_put(kn); |
fd7b9f7b TH |
947 | return ERR_PTR(rc); |
948 | } | |
949 | ||
ea015218 EB |
950 | /** |
951 | * kernfs_create_empty_dir - create an always empty directory | |
952 | * @parent: parent in which to create a new directory | |
953 | * @name: name of the new directory | |
954 | * | |
955 | * Returns the created node on success, ERR_PTR() value on failure. | |
956 | */ | |
957 | struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, | |
958 | const char *name) | |
959 | { | |
960 | struct kernfs_node *kn; | |
961 | int rc; | |
962 | ||
963 | /* allocate */ | |
964 | kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR); | |
965 | if (!kn) | |
966 | return ERR_PTR(-ENOMEM); | |
967 | ||
968 | kn->flags |= KERNFS_EMPTY_DIR; | |
969 | kn->dir.root = parent->dir.root; | |
970 | kn->ns = NULL; | |
971 | kn->priv = NULL; | |
972 | ||
973 | /* link in */ | |
974 | rc = kernfs_add_one(kn); | |
975 | if (!rc) | |
976 | return kn; | |
977 | ||
978 | kernfs_put(kn); | |
979 | return ERR_PTR(rc); | |
980 | } | |
981 | ||
c637b8ac TH |
982 | static struct dentry *kernfs_iop_lookup(struct inode *dir, |
983 | struct dentry *dentry, | |
984 | unsigned int flags) | |
fd7b9f7b | 985 | { |
19bbb926 | 986 | struct dentry *ret; |
324a56e1 TH |
987 | struct kernfs_node *parent = dentry->d_parent->d_fsdata; |
988 | struct kernfs_node *kn; | |
fd7b9f7b TH |
989 | struct inode *inode; |
990 | const void *ns = NULL; | |
991 | ||
a797bfc3 | 992 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 993 | |
324a56e1 | 994 | if (kernfs_ns_enabled(parent)) |
c525aadd | 995 | ns = kernfs_info(dir->i_sb)->ns; |
fd7b9f7b | 996 | |
324a56e1 | 997 | kn = kernfs_find_ns(parent, dentry->d_name.name, ns); |
fd7b9f7b TH |
998 | |
999 | /* no such entry */ | |
b9c9dad0 | 1000 | if (!kn || !kernfs_active(kn)) { |
19bbb926 | 1001 | ret = NULL; |
fd7b9f7b TH |
1002 | goto out_unlock; |
1003 | } | |
324a56e1 TH |
1004 | kernfs_get(kn); |
1005 | dentry->d_fsdata = kn; | |
fd7b9f7b TH |
1006 | |
1007 | /* attach dentry and inode */ | |
c637b8ac | 1008 | inode = kernfs_get_inode(dir->i_sb, kn); |
fd7b9f7b TH |
1009 | if (!inode) { |
1010 | ret = ERR_PTR(-ENOMEM); | |
1011 | goto out_unlock; | |
1012 | } | |
1013 | ||
1014 | /* instantiate and hash dentry */ | |
41d28bca | 1015 | ret = d_splice_alias(inode, dentry); |
fd7b9f7b | 1016 | out_unlock: |
a797bfc3 | 1017 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
1018 | return ret; |
1019 | } | |
1020 | ||
80b9bbef TH |
1021 | static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, |
1022 | umode_t mode) | |
1023 | { | |
1024 | struct kernfs_node *parent = dir->i_private; | |
90c07c89 | 1025 | struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; |
07c7530d | 1026 | int ret; |
80b9bbef | 1027 | |
90c07c89 | 1028 | if (!scops || !scops->mkdir) |
80b9bbef TH |
1029 | return -EPERM; |
1030 | ||
07c7530d TH |
1031 | if (!kernfs_get_active(parent)) |
1032 | return -ENODEV; | |
1033 | ||
90c07c89 | 1034 | ret = scops->mkdir(parent, dentry->d_name.name, mode); |
07c7530d TH |
1035 | |
1036 | kernfs_put_active(parent); | |
1037 | return ret; | |
80b9bbef TH |
1038 | } |
1039 | ||
1040 | static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) | |
1041 | { | |
1042 | struct kernfs_node *kn = dentry->d_fsdata; | |
90c07c89 | 1043 | struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; |
07c7530d | 1044 | int ret; |
80b9bbef | 1045 | |
90c07c89 | 1046 | if (!scops || !scops->rmdir) |
80b9bbef TH |
1047 | return -EPERM; |
1048 | ||
07c7530d TH |
1049 | if (!kernfs_get_active(kn)) |
1050 | return -ENODEV; | |
1051 | ||
90c07c89 | 1052 | ret = scops->rmdir(kn); |
07c7530d TH |
1053 | |
1054 | kernfs_put_active(kn); | |
1055 | return ret; | |
80b9bbef TH |
1056 | } |
1057 | ||
1058 | static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, | |
1cd66c93 MS |
1059 | struct inode *new_dir, struct dentry *new_dentry, |
1060 | unsigned int flags) | |
80b9bbef TH |
1061 | { |
1062 | struct kernfs_node *kn = old_dentry->d_fsdata; | |
1063 | struct kernfs_node *new_parent = new_dir->i_private; | |
90c07c89 | 1064 | struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; |
07c7530d | 1065 | int ret; |
80b9bbef | 1066 | |
1cd66c93 MS |
1067 | if (flags) |
1068 | return -EINVAL; | |
1069 | ||
90c07c89 | 1070 | if (!scops || !scops->rename) |
80b9bbef TH |
1071 | return -EPERM; |
1072 | ||
07c7530d TH |
1073 | if (!kernfs_get_active(kn)) |
1074 | return -ENODEV; | |
1075 | ||
1076 | if (!kernfs_get_active(new_parent)) { | |
1077 | kernfs_put_active(kn); | |
1078 | return -ENODEV; | |
1079 | } | |
1080 | ||
90c07c89 | 1081 | ret = scops->rename(kn, new_parent, new_dentry->d_name.name); |
07c7530d TH |
1082 | |
1083 | kernfs_put_active(new_parent); | |
1084 | kernfs_put_active(kn); | |
1085 | return ret; | |
80b9bbef TH |
1086 | } |
1087 | ||
a797bfc3 | 1088 | const struct inode_operations kernfs_dir_iops = { |
c637b8ac TH |
1089 | .lookup = kernfs_iop_lookup, |
1090 | .permission = kernfs_iop_permission, | |
1091 | .setattr = kernfs_iop_setattr, | |
1092 | .getattr = kernfs_iop_getattr, | |
c637b8ac | 1093 | .listxattr = kernfs_iop_listxattr, |
80b9bbef TH |
1094 | |
1095 | .mkdir = kernfs_iop_mkdir, | |
1096 | .rmdir = kernfs_iop_rmdir, | |
1097 | .rename = kernfs_iop_rename, | |
fd7b9f7b TH |
1098 | }; |
1099 | ||
c637b8ac | 1100 | static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) |
fd7b9f7b | 1101 | { |
324a56e1 | 1102 | struct kernfs_node *last; |
fd7b9f7b TH |
1103 | |
1104 | while (true) { | |
1105 | struct rb_node *rbn; | |
1106 | ||
1107 | last = pos; | |
1108 | ||
df23fc39 | 1109 | if (kernfs_type(pos) != KERNFS_DIR) |
fd7b9f7b TH |
1110 | break; |
1111 | ||
adc5e8b5 | 1112 | rbn = rb_first(&pos->dir.children); |
fd7b9f7b TH |
1113 | if (!rbn) |
1114 | break; | |
1115 | ||
324a56e1 | 1116 | pos = rb_to_kn(rbn); |
fd7b9f7b TH |
1117 | } |
1118 | ||
1119 | return last; | |
1120 | } | |
1121 | ||
1122 | /** | |
c637b8ac | 1123 | * kernfs_next_descendant_post - find the next descendant for post-order walk |
fd7b9f7b | 1124 | * @pos: the current position (%NULL to initiate traversal) |
324a56e1 | 1125 | * @root: kernfs_node whose descendants to walk |
fd7b9f7b TH |
1126 | * |
1127 | * Find the next descendant to visit for post-order traversal of @root's | |
1128 | * descendants. @root is included in the iteration and the last node to be | |
1129 | * visited. | |
1130 | */ | |
c637b8ac TH |
1131 | static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, |
1132 | struct kernfs_node *root) | |
fd7b9f7b TH |
1133 | { |
1134 | struct rb_node *rbn; | |
1135 | ||
a797bfc3 | 1136 | lockdep_assert_held(&kernfs_mutex); |
fd7b9f7b TH |
1137 | |
1138 | /* if first iteration, visit leftmost descendant which may be root */ | |
1139 | if (!pos) | |
c637b8ac | 1140 | return kernfs_leftmost_descendant(root); |
fd7b9f7b TH |
1141 | |
1142 | /* if we visited @root, we're done */ | |
1143 | if (pos == root) | |
1144 | return NULL; | |
1145 | ||
1146 | /* if there's an unvisited sibling, visit its leftmost descendant */ | |
adc5e8b5 | 1147 | rbn = rb_next(&pos->rb); |
fd7b9f7b | 1148 | if (rbn) |
c637b8ac | 1149 | return kernfs_leftmost_descendant(rb_to_kn(rbn)); |
fd7b9f7b TH |
1150 | |
1151 | /* no sibling left, visit parent */ | |
adc5e8b5 | 1152 | return pos->parent; |
fd7b9f7b TH |
1153 | } |
1154 | ||
d35258ef TH |
1155 | /** |
1156 | * kernfs_activate - activate a node which started deactivated | |
1157 | * @kn: kernfs_node whose subtree is to be activated | |
1158 | * | |
1159 | * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node | |
1160 | * needs to be explicitly activated. A node which hasn't been activated | |
1161 | * isn't visible to userland and deactivation is skipped during its | |
1162 | * removal. This is useful to construct atomic init sequences where | |
1163 | * creation of multiple nodes should either succeed or fail atomically. | |
1164 | * | |
1165 | * The caller is responsible for ensuring that this function is not called | |
1166 | * after kernfs_remove*() is invoked on @kn. | |
1167 | */ | |
1168 | void kernfs_activate(struct kernfs_node *kn) | |
1169 | { | |
1170 | struct kernfs_node *pos; | |
1171 | ||
1172 | mutex_lock(&kernfs_mutex); | |
1173 | ||
1174 | pos = NULL; | |
1175 | while ((pos = kernfs_next_descendant_post(pos, kn))) { | |
1176 | if (!pos || (pos->flags & KERNFS_ACTIVATED)) | |
1177 | continue; | |
1178 | ||
1179 | WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); | |
1180 | WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); | |
1181 | ||
1182 | atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); | |
1183 | pos->flags |= KERNFS_ACTIVATED; | |
1184 | } | |
1185 | ||
1186 | mutex_unlock(&kernfs_mutex); | |
1187 | } | |
1188 | ||
988cd7af | 1189 | static void __kernfs_remove(struct kernfs_node *kn) |
fd7b9f7b | 1190 | { |
35beab06 TH |
1191 | struct kernfs_node *pos; |
1192 | ||
1193 | lockdep_assert_held(&kernfs_mutex); | |
fd7b9f7b | 1194 | |
6b0afc2a TH |
1195 | /* |
1196 | * Short-circuit if non-root @kn has already finished removal. | |
1197 | * This is for kernfs_remove_self() which plays with active ref | |
1198 | * after removal. | |
1199 | */ | |
1200 | if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) | |
ce9b499c GKH |
1201 | return; |
1202 | ||
c637b8ac | 1203 | pr_debug("kernfs %s: removing\n", kn->name); |
fd7b9f7b | 1204 | |
81c173cb | 1205 | /* prevent any new usage under @kn by deactivating all nodes */ |
35beab06 TH |
1206 | pos = NULL; |
1207 | while ((pos = kernfs_next_descendant_post(pos, kn))) | |
81c173cb TH |
1208 | if (kernfs_active(pos)) |
1209 | atomic_add(KN_DEACTIVATED_BIAS, &pos->active); | |
35beab06 TH |
1210 | |
1211 | /* deactivate and unlink the subtree node-by-node */ | |
fd7b9f7b | 1212 | do { |
35beab06 TH |
1213 | pos = kernfs_leftmost_descendant(kn); |
1214 | ||
1215 | /* | |
81c173cb TH |
1216 | * kernfs_drain() drops kernfs_mutex temporarily and @pos's |
1217 | * base ref could have been put by someone else by the time | |
1218 | * the function returns. Make sure it doesn't go away | |
1219 | * underneath us. | |
35beab06 TH |
1220 | */ |
1221 | kernfs_get(pos); | |
1222 | ||
d35258ef TH |
1223 | /* |
1224 | * Drain iff @kn was activated. This avoids draining and | |
1225 | * its lockdep annotations for nodes which have never been | |
1226 | * activated and allows embedding kernfs_remove() in create | |
1227 | * error paths without worrying about draining. | |
1228 | */ | |
1229 | if (kn->flags & KERNFS_ACTIVATED) | |
1230 | kernfs_drain(pos); | |
1231 | else | |
1232 | WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); | |
35beab06 TH |
1233 | |
1234 | /* | |
1235 | * kernfs_unlink_sibling() succeeds once per node. Use it | |
1236 | * to decide who's responsible for cleanups. | |
1237 | */ | |
1238 | if (!pos->parent || kernfs_unlink_sibling(pos)) { | |
1239 | struct kernfs_iattrs *ps_iattr = | |
1240 | pos->parent ? pos->parent->iattr : NULL; | |
1241 | ||
1242 | /* update timestamps on the parent */ | |
1243 | if (ps_iattr) { | |
3a3a5fec DD |
1244 | ktime_get_real_ts(&ps_iattr->ia_iattr.ia_ctime); |
1245 | ps_iattr->ia_iattr.ia_mtime = | |
1246 | ps_iattr->ia_iattr.ia_ctime; | |
35beab06 TH |
1247 | } |
1248 | ||
988cd7af | 1249 | kernfs_put(pos); |
35beab06 TH |
1250 | } |
1251 | ||
1252 | kernfs_put(pos); | |
1253 | } while (pos != kn); | |
fd7b9f7b TH |
1254 | } |
1255 | ||
1256 | /** | |
324a56e1 TH |
1257 | * kernfs_remove - remove a kernfs_node recursively |
1258 | * @kn: the kernfs_node to remove | |
fd7b9f7b | 1259 | * |
324a56e1 | 1260 | * Remove @kn along with all its subdirectories and files. |
fd7b9f7b | 1261 | */ |
324a56e1 | 1262 | void kernfs_remove(struct kernfs_node *kn) |
fd7b9f7b | 1263 | { |
988cd7af TH |
1264 | mutex_lock(&kernfs_mutex); |
1265 | __kernfs_remove(kn); | |
1266 | mutex_unlock(&kernfs_mutex); | |
fd7b9f7b TH |
1267 | } |
1268 | ||
6b0afc2a TH |
1269 | /** |
1270 | * kernfs_break_active_protection - break out of active protection | |
1271 | * @kn: the self kernfs_node | |
1272 | * | |
1273 | * The caller must be running off of a kernfs operation which is invoked | |
1274 | * with an active reference - e.g. one of kernfs_ops. Each invocation of | |
1275 | * this function must also be matched with an invocation of | |
1276 | * kernfs_unbreak_active_protection(). | |
1277 | * | |
1278 | * This function releases the active reference of @kn the caller is | |
1279 | * holding. Once this function is called, @kn may be removed at any point | |
1280 | * and the caller is solely responsible for ensuring that the objects it | |
1281 | * dereferences are accessible. | |
1282 | */ | |
1283 | void kernfs_break_active_protection(struct kernfs_node *kn) | |
1284 | { | |
1285 | /* | |
1286 | * Take out ourself out of the active ref dependency chain. If | |
1287 | * we're called without an active ref, lockdep will complain. | |
1288 | */ | |
1289 | kernfs_put_active(kn); | |
1290 | } | |
1291 | ||
1292 | /** | |
1293 | * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() | |
1294 | * @kn: the self kernfs_node | |
1295 | * | |
1296 | * If kernfs_break_active_protection() was called, this function must be | |
1297 | * invoked before finishing the kernfs operation. Note that while this | |
1298 | * function restores the active reference, it doesn't and can't actually | |
1299 | * restore the active protection - @kn may already or be in the process of | |
1300 | * being removed. Once kernfs_break_active_protection() is invoked, that | |
1301 | * protection is irreversibly gone for the kernfs operation instance. | |
1302 | * | |
1303 | * While this function may be called at any point after | |
1304 | * kernfs_break_active_protection() is invoked, its most useful location | |
1305 | * would be right before the enclosing kernfs operation returns. | |
1306 | */ | |
1307 | void kernfs_unbreak_active_protection(struct kernfs_node *kn) | |
1308 | { | |
1309 | /* | |
1310 | * @kn->active could be in any state; however, the increment we do | |
1311 | * here will be undone as soon as the enclosing kernfs operation | |
1312 | * finishes and this temporary bump can't break anything. If @kn | |
1313 | * is alive, nothing changes. If @kn is being deactivated, the | |
1314 | * soon-to-follow put will either finish deactivation or restore | |
1315 | * deactivated state. If @kn is already removed, the temporary | |
1316 | * bump is guaranteed to be gone before @kn is released. | |
1317 | */ | |
1318 | atomic_inc(&kn->active); | |
1319 | if (kernfs_lockdep(kn)) | |
1320 | rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); | |
1321 | } | |
1322 | ||
1323 | /** | |
1324 | * kernfs_remove_self - remove a kernfs_node from its own method | |
1325 | * @kn: the self kernfs_node to remove | |
1326 | * | |
1327 | * The caller must be running off of a kernfs operation which is invoked | |
1328 | * with an active reference - e.g. one of kernfs_ops. This can be used to | |
1329 | * implement a file operation which deletes itself. | |
1330 | * | |
1331 | * For example, the "delete" file for a sysfs device directory can be | |
1332 | * implemented by invoking kernfs_remove_self() on the "delete" file | |
1333 | * itself. This function breaks the circular dependency of trying to | |
1334 | * deactivate self while holding an active ref itself. It isn't necessary | |
1335 | * to modify the usual removal path to use kernfs_remove_self(). The | |
1336 | * "delete" implementation can simply invoke kernfs_remove_self() on self | |
1337 | * before proceeding with the usual removal path. kernfs will ignore later | |
1338 | * kernfs_remove() on self. | |
1339 | * | |
1340 | * kernfs_remove_self() can be called multiple times concurrently on the | |
1341 | * same kernfs_node. Only the first one actually performs removal and | |
1342 | * returns %true. All others will wait until the kernfs operation which | |
1343 | * won self-removal finishes and return %false. Note that the losers wait | |
1344 | * for the completion of not only the winning kernfs_remove_self() but also | |
1345 | * the whole kernfs_ops which won the arbitration. This can be used to | |
1346 | * guarantee, for example, all concurrent writes to a "delete" file to | |
1347 | * finish only after the whole operation is complete. | |
1348 | */ | |
1349 | bool kernfs_remove_self(struct kernfs_node *kn) | |
1350 | { | |
1351 | bool ret; | |
1352 | ||
1353 | mutex_lock(&kernfs_mutex); | |
1354 | kernfs_break_active_protection(kn); | |
1355 | ||
1356 | /* | |
1357 | * SUICIDAL is used to arbitrate among competing invocations. Only | |
1358 | * the first one will actually perform removal. When the removal | |
1359 | * is complete, SUICIDED is set and the active ref is restored | |
1360 | * while holding kernfs_mutex. The ones which lost arbitration | |
1361 | * waits for SUICDED && drained which can happen only after the | |
1362 | * enclosing kernfs operation which executed the winning instance | |
1363 | * of kernfs_remove_self() finished. | |
1364 | */ | |
1365 | if (!(kn->flags & KERNFS_SUICIDAL)) { | |
1366 | kn->flags |= KERNFS_SUICIDAL; | |
1367 | __kernfs_remove(kn); | |
1368 | kn->flags |= KERNFS_SUICIDED; | |
1369 | ret = true; | |
1370 | } else { | |
1371 | wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; | |
1372 | DEFINE_WAIT(wait); | |
1373 | ||
1374 | while (true) { | |
1375 | prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); | |
1376 | ||
1377 | if ((kn->flags & KERNFS_SUICIDED) && | |
1378 | atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) | |
1379 | break; | |
1380 | ||
1381 | mutex_unlock(&kernfs_mutex); | |
1382 | schedule(); | |
1383 | mutex_lock(&kernfs_mutex); | |
1384 | } | |
1385 | finish_wait(waitq, &wait); | |
1386 | WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); | |
1387 | ret = false; | |
1388 | } | |
1389 | ||
1390 | /* | |
1391 | * This must be done while holding kernfs_mutex; otherwise, waiting | |
1392 | * for SUICIDED && deactivated could finish prematurely. | |
1393 | */ | |
1394 | kernfs_unbreak_active_protection(kn); | |
1395 | ||
1396 | mutex_unlock(&kernfs_mutex); | |
1397 | return ret; | |
1398 | } | |
1399 | ||
fd7b9f7b | 1400 | /** |
324a56e1 TH |
1401 | * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it |
1402 | * @parent: parent of the target | |
1403 | * @name: name of the kernfs_node to remove | |
1404 | * @ns: namespace tag of the kernfs_node to remove | |
fd7b9f7b | 1405 | * |
324a56e1 TH |
1406 | * Look for the kernfs_node with @name and @ns under @parent and remove it. |
1407 | * Returns 0 on success, -ENOENT if such entry doesn't exist. | |
fd7b9f7b | 1408 | */ |
324a56e1 | 1409 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, |
fd7b9f7b TH |
1410 | const void *ns) |
1411 | { | |
324a56e1 | 1412 | struct kernfs_node *kn; |
fd7b9f7b | 1413 | |
324a56e1 | 1414 | if (!parent) { |
c637b8ac | 1415 | WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", |
fd7b9f7b TH |
1416 | name); |
1417 | return -ENOENT; | |
1418 | } | |
1419 | ||
988cd7af | 1420 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 1421 | |
324a56e1 TH |
1422 | kn = kernfs_find_ns(parent, name, ns); |
1423 | if (kn) | |
988cd7af | 1424 | __kernfs_remove(kn); |
fd7b9f7b | 1425 | |
988cd7af | 1426 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b | 1427 | |
324a56e1 | 1428 | if (kn) |
fd7b9f7b TH |
1429 | return 0; |
1430 | else | |
1431 | return -ENOENT; | |
1432 | } | |
1433 | ||
1434 | /** | |
1435 | * kernfs_rename_ns - move and rename a kernfs_node | |
324a56e1 | 1436 | * @kn: target node |
fd7b9f7b TH |
1437 | * @new_parent: new parent to put @sd under |
1438 | * @new_name: new name | |
1439 | * @new_ns: new namespace tag | |
1440 | */ | |
324a56e1 | 1441 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
fd7b9f7b TH |
1442 | const char *new_name, const void *new_ns) |
1443 | { | |
3eef34ad TH |
1444 | struct kernfs_node *old_parent; |
1445 | const char *old_name = NULL; | |
fd7b9f7b TH |
1446 | int error; |
1447 | ||
3eef34ad TH |
1448 | /* can't move or rename root */ |
1449 | if (!kn->parent) | |
1450 | return -EINVAL; | |
1451 | ||
798c75a0 GKH |
1452 | mutex_lock(&kernfs_mutex); |
1453 | ||
d0ae3d43 | 1454 | error = -ENOENT; |
ea015218 EB |
1455 | if (!kernfs_active(kn) || !kernfs_active(new_parent) || |
1456 | (new_parent->flags & KERNFS_EMPTY_DIR)) | |
d0ae3d43 TH |
1457 | goto out; |
1458 | ||
fd7b9f7b | 1459 | error = 0; |
adc5e8b5 TH |
1460 | if ((kn->parent == new_parent) && (kn->ns == new_ns) && |
1461 | (strcmp(kn->name, new_name) == 0)) | |
798c75a0 | 1462 | goto out; /* nothing to rename */ |
fd7b9f7b TH |
1463 | |
1464 | error = -EEXIST; | |
1465 | if (kernfs_find_ns(new_parent, new_name, new_ns)) | |
798c75a0 | 1466 | goto out; |
fd7b9f7b | 1467 | |
324a56e1 | 1468 | /* rename kernfs_node */ |
adc5e8b5 | 1469 | if (strcmp(kn->name, new_name) != 0) { |
fd7b9f7b | 1470 | error = -ENOMEM; |
75287a67 | 1471 | new_name = kstrdup_const(new_name, GFP_KERNEL); |
fd7b9f7b | 1472 | if (!new_name) |
798c75a0 | 1473 | goto out; |
3eef34ad TH |
1474 | } else { |
1475 | new_name = NULL; | |
fd7b9f7b TH |
1476 | } |
1477 | ||
1478 | /* | |
1479 | * Move to the appropriate place in the appropriate directories rbtree. | |
1480 | */ | |
c637b8ac | 1481 | kernfs_unlink_sibling(kn); |
fd7b9f7b | 1482 | kernfs_get(new_parent); |
3eef34ad TH |
1483 | |
1484 | /* rename_lock protects ->parent and ->name accessors */ | |
1485 | spin_lock_irq(&kernfs_rename_lock); | |
1486 | ||
1487 | old_parent = kn->parent; | |
adc5e8b5 | 1488 | kn->parent = new_parent; |
3eef34ad TH |
1489 | |
1490 | kn->ns = new_ns; | |
1491 | if (new_name) { | |
dfeb0750 | 1492 | old_name = kn->name; |
3eef34ad TH |
1493 | kn->name = new_name; |
1494 | } | |
1495 | ||
1496 | spin_unlock_irq(&kernfs_rename_lock); | |
1497 | ||
9561a896 | 1498 | kn->hash = kernfs_name_hash(kn->name, kn->ns); |
c637b8ac | 1499 | kernfs_link_sibling(kn); |
fd7b9f7b | 1500 | |
3eef34ad | 1501 | kernfs_put(old_parent); |
75287a67 | 1502 | kfree_const(old_name); |
3eef34ad | 1503 | |
fd7b9f7b | 1504 | error = 0; |
798c75a0 | 1505 | out: |
a797bfc3 | 1506 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
1507 | return error; |
1508 | } | |
1509 | ||
fd7b9f7b | 1510 | /* Relationship between s_mode and the DT_xxx types */ |
324a56e1 | 1511 | static inline unsigned char dt_type(struct kernfs_node *kn) |
fd7b9f7b | 1512 | { |
adc5e8b5 | 1513 | return (kn->mode >> 12) & 15; |
fd7b9f7b TH |
1514 | } |
1515 | ||
c637b8ac | 1516 | static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) |
fd7b9f7b TH |
1517 | { |
1518 | kernfs_put(filp->private_data); | |
1519 | return 0; | |
1520 | } | |
1521 | ||
c637b8ac | 1522 | static struct kernfs_node *kernfs_dir_pos(const void *ns, |
324a56e1 | 1523 | struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) |
fd7b9f7b TH |
1524 | { |
1525 | if (pos) { | |
81c173cb | 1526 | int valid = kernfs_active(pos) && |
798c75a0 | 1527 | pos->parent == parent && hash == pos->hash; |
fd7b9f7b TH |
1528 | kernfs_put(pos); |
1529 | if (!valid) | |
1530 | pos = NULL; | |
1531 | } | |
1532 | if (!pos && (hash > 1) && (hash < INT_MAX)) { | |
adc5e8b5 | 1533 | struct rb_node *node = parent->dir.children.rb_node; |
fd7b9f7b | 1534 | while (node) { |
324a56e1 | 1535 | pos = rb_to_kn(node); |
fd7b9f7b | 1536 | |
adc5e8b5 | 1537 | if (hash < pos->hash) |
fd7b9f7b | 1538 | node = node->rb_left; |
adc5e8b5 | 1539 | else if (hash > pos->hash) |
fd7b9f7b TH |
1540 | node = node->rb_right; |
1541 | else | |
1542 | break; | |
1543 | } | |
1544 | } | |
b9c9dad0 TH |
1545 | /* Skip over entries which are dying/dead or in the wrong namespace */ |
1546 | while (pos && (!kernfs_active(pos) || pos->ns != ns)) { | |
adc5e8b5 | 1547 | struct rb_node *node = rb_next(&pos->rb); |
fd7b9f7b TH |
1548 | if (!node) |
1549 | pos = NULL; | |
1550 | else | |
324a56e1 | 1551 | pos = rb_to_kn(node); |
fd7b9f7b TH |
1552 | } |
1553 | return pos; | |
1554 | } | |
1555 | ||
c637b8ac | 1556 | static struct kernfs_node *kernfs_dir_next_pos(const void *ns, |
324a56e1 | 1557 | struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) |
fd7b9f7b | 1558 | { |
c637b8ac | 1559 | pos = kernfs_dir_pos(ns, parent, ino, pos); |
b9c9dad0 | 1560 | if (pos) { |
fd7b9f7b | 1561 | do { |
adc5e8b5 | 1562 | struct rb_node *node = rb_next(&pos->rb); |
fd7b9f7b TH |
1563 | if (!node) |
1564 | pos = NULL; | |
1565 | else | |
324a56e1 | 1566 | pos = rb_to_kn(node); |
b9c9dad0 TH |
1567 | } while (pos && (!kernfs_active(pos) || pos->ns != ns)); |
1568 | } | |
fd7b9f7b TH |
1569 | return pos; |
1570 | } | |
1571 | ||
c637b8ac | 1572 | static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) |
fd7b9f7b TH |
1573 | { |
1574 | struct dentry *dentry = file->f_path.dentry; | |
324a56e1 TH |
1575 | struct kernfs_node *parent = dentry->d_fsdata; |
1576 | struct kernfs_node *pos = file->private_data; | |
fd7b9f7b TH |
1577 | const void *ns = NULL; |
1578 | ||
1579 | if (!dir_emit_dots(file, ctx)) | |
1580 | return 0; | |
a797bfc3 | 1581 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 1582 | |
324a56e1 | 1583 | if (kernfs_ns_enabled(parent)) |
c525aadd | 1584 | ns = kernfs_info(dentry->d_sb)->ns; |
fd7b9f7b | 1585 | |
c637b8ac | 1586 | for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); |
fd7b9f7b | 1587 | pos; |
c637b8ac | 1588 | pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { |
adc5e8b5 | 1589 | const char *name = pos->name; |
fd7b9f7b TH |
1590 | unsigned int type = dt_type(pos); |
1591 | int len = strlen(name); | |
adc5e8b5 | 1592 | ino_t ino = pos->ino; |
fd7b9f7b | 1593 | |
adc5e8b5 | 1594 | ctx->pos = pos->hash; |
fd7b9f7b TH |
1595 | file->private_data = pos; |
1596 | kernfs_get(pos); | |
1597 | ||
a797bfc3 | 1598 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
1599 | if (!dir_emit(ctx, name, len, ino, type)) |
1600 | return 0; | |
a797bfc3 | 1601 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 1602 | } |
a797bfc3 | 1603 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
1604 | file->private_data = NULL; |
1605 | ctx->pos = INT_MAX; | |
1606 | return 0; | |
1607 | } | |
1608 | ||
a797bfc3 | 1609 | const struct file_operations kernfs_dir_fops = { |
fd7b9f7b | 1610 | .read = generic_read_dir, |
8cb0d2c1 | 1611 | .iterate_shared = kernfs_fop_readdir, |
c637b8ac | 1612 | .release = kernfs_dir_fop_release, |
8cb0d2c1 | 1613 | .llseek = generic_file_llseek, |
fd7b9f7b | 1614 | }; |