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