Commit | Line | Data |
---|---|---|
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 | |
ea1c472d | 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); |
fd7b9f7b | 22 | |
adc5e8b5 | 23 | #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) |
fd7b9f7b | 24 | |
a69d001c TH |
25 | static bool kernfs_lockdep(struct kernfs_node *kn) |
26 | { | |
27 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
28 | return kn->flags & KERNFS_LOCKDEP; | |
29 | #else | |
30 | return false; | |
31 | #endif | |
32 | } | |
33 | ||
fd7b9f7b | 34 | /** |
c637b8ac | 35 | * kernfs_name_hash |
fd7b9f7b TH |
36 | * @name: Null terminated string to hash |
37 | * @ns: Namespace tag to hash | |
38 | * | |
39 | * Returns 31 bit hash of ns + name (so it fits in an off_t ) | |
40 | */ | |
c637b8ac | 41 | static unsigned int kernfs_name_hash(const char *name, const void *ns) |
fd7b9f7b TH |
42 | { |
43 | unsigned long hash = init_name_hash(); | |
44 | unsigned int len = strlen(name); | |
45 | while (len--) | |
46 | hash = partial_name_hash(*name++, hash); | |
47 | hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31)); | |
48 | hash &= 0x7fffffffU; | |
49 | /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ | |
50 | if (hash < 1) | |
51 | hash += 2; | |
52 | if (hash >= INT_MAX) | |
53 | hash = INT_MAX - 1; | |
54 | return hash; | |
55 | } | |
56 | ||
c637b8ac TH |
57 | static int kernfs_name_compare(unsigned int hash, const char *name, |
58 | const void *ns, const struct kernfs_node *kn) | |
fd7b9f7b | 59 | { |
adc5e8b5 TH |
60 | if (hash != kn->hash) |
61 | return hash - kn->hash; | |
62 | if (ns != kn->ns) | |
63 | return ns - kn->ns; | |
64 | return strcmp(name, kn->name); | |
fd7b9f7b TH |
65 | } |
66 | ||
c637b8ac TH |
67 | static int kernfs_sd_compare(const struct kernfs_node *left, |
68 | const struct kernfs_node *right) | |
fd7b9f7b | 69 | { |
c637b8ac | 70 | return kernfs_name_compare(left->hash, left->name, left->ns, right); |
fd7b9f7b TH |
71 | } |
72 | ||
73 | /** | |
c637b8ac | 74 | * kernfs_link_sibling - link kernfs_node into sibling rbtree |
324a56e1 | 75 | * @kn: kernfs_node of interest |
fd7b9f7b | 76 | * |
324a56e1 | 77 | * Link @kn into its sibling rbtree which starts from |
adc5e8b5 | 78 | * @kn->parent->dir.children. |
fd7b9f7b TH |
79 | * |
80 | * Locking: | |
a797bfc3 | 81 | * mutex_lock(kernfs_mutex) |
fd7b9f7b TH |
82 | * |
83 | * RETURNS: | |
84 | * 0 on susccess -EEXIST on failure. | |
85 | */ | |
c637b8ac | 86 | static int kernfs_link_sibling(struct kernfs_node *kn) |
fd7b9f7b | 87 | { |
adc5e8b5 | 88 | struct rb_node **node = &kn->parent->dir.children.rb_node; |
fd7b9f7b TH |
89 | struct rb_node *parent = NULL; |
90 | ||
df23fc39 | 91 | if (kernfs_type(kn) == KERNFS_DIR) |
adc5e8b5 | 92 | kn->parent->dir.subdirs++; |
fd7b9f7b TH |
93 | |
94 | while (*node) { | |
324a56e1 | 95 | struct kernfs_node *pos; |
fd7b9f7b TH |
96 | int result; |
97 | ||
324a56e1 | 98 | pos = rb_to_kn(*node); |
fd7b9f7b | 99 | parent = *node; |
c637b8ac | 100 | result = kernfs_sd_compare(kn, pos); |
fd7b9f7b | 101 | if (result < 0) |
adc5e8b5 | 102 | node = &pos->rb.rb_left; |
fd7b9f7b | 103 | else if (result > 0) |
adc5e8b5 | 104 | node = &pos->rb.rb_right; |
fd7b9f7b TH |
105 | else |
106 | return -EEXIST; | |
107 | } | |
108 | /* add new node and rebalance the tree */ | |
adc5e8b5 TH |
109 | rb_link_node(&kn->rb, parent, node); |
110 | rb_insert_color(&kn->rb, &kn->parent->dir.children); | |
fd7b9f7b TH |
111 | return 0; |
112 | } | |
113 | ||
114 | /** | |
c637b8ac | 115 | * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree |
324a56e1 | 116 | * @kn: kernfs_node of interest |
fd7b9f7b | 117 | * |
324a56e1 | 118 | * Unlink @kn from its sibling rbtree which starts from |
adc5e8b5 | 119 | * kn->parent->dir.children. |
fd7b9f7b TH |
120 | * |
121 | * Locking: | |
a797bfc3 | 122 | * mutex_lock(kernfs_mutex) |
fd7b9f7b | 123 | */ |
f601f9a2 | 124 | static bool kernfs_unlink_sibling(struct kernfs_node *kn) |
fd7b9f7b | 125 | { |
f601f9a2 TH |
126 | if (RB_EMPTY_NODE(&kn->rb)) |
127 | return false; | |
128 | ||
df23fc39 | 129 | if (kernfs_type(kn) == KERNFS_DIR) |
adc5e8b5 | 130 | kn->parent->dir.subdirs--; |
fd7b9f7b | 131 | |
adc5e8b5 | 132 | rb_erase(&kn->rb, &kn->parent->dir.children); |
ae34372e | 133 | RB_CLEAR_NODE(&kn->rb); |
f601f9a2 | 134 | return true; |
fd7b9f7b TH |
135 | } |
136 | ||
137 | /** | |
c637b8ac | 138 | * kernfs_get_active - get an active reference to kernfs_node |
324a56e1 | 139 | * @kn: kernfs_node to get an active reference to |
fd7b9f7b | 140 | * |
324a56e1 | 141 | * Get an active reference of @kn. This function is noop if @kn |
fd7b9f7b TH |
142 | * is NULL. |
143 | * | |
144 | * RETURNS: | |
324a56e1 | 145 | * Pointer to @kn on success, NULL on failure. |
fd7b9f7b | 146 | */ |
c637b8ac | 147 | struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) |
fd7b9f7b | 148 | { |
324a56e1 | 149 | if (unlikely(!kn)) |
fd7b9f7b TH |
150 | return NULL; |
151 | ||
adc5e8b5 | 152 | if (!atomic_inc_unless_negative(&kn->active)) |
fd7b9f7b TH |
153 | return NULL; |
154 | ||
a69d001c | 155 | if (kernfs_lockdep(kn)) |
324a56e1 TH |
156 | rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); |
157 | return kn; | |
fd7b9f7b TH |
158 | } |
159 | ||
160 | /** | |
c637b8ac | 161 | * kernfs_put_active - put an active reference to kernfs_node |
324a56e1 | 162 | * @kn: kernfs_node to put an active reference to |
fd7b9f7b | 163 | * |
324a56e1 | 164 | * Put an active reference to @kn. This function is noop if @kn |
fd7b9f7b TH |
165 | * is NULL. |
166 | */ | |
c637b8ac | 167 | void kernfs_put_active(struct kernfs_node *kn) |
fd7b9f7b | 168 | { |
ea1c472d | 169 | struct kernfs_root *root = kernfs_root(kn); |
fd7b9f7b TH |
170 | int v; |
171 | ||
324a56e1 | 172 | if (unlikely(!kn)) |
fd7b9f7b TH |
173 | return; |
174 | ||
a69d001c | 175 | if (kernfs_lockdep(kn)) |
324a56e1 | 176 | rwsem_release(&kn->dep_map, 1, _RET_IP_); |
adc5e8b5 | 177 | v = atomic_dec_return(&kn->active); |
df23fc39 | 178 | if (likely(v != KN_DEACTIVATED_BIAS)) |
fd7b9f7b TH |
179 | return; |
180 | ||
ea1c472d | 181 | wake_up_all(&root->deactivate_waitq); |
fd7b9f7b TH |
182 | } |
183 | ||
184 | /** | |
ae34372e TH |
185 | * kernfs_drain - drain kernfs_node |
186 | * @kn: kernfs_node to drain | |
fd7b9f7b | 187 | * |
45a140e5 TH |
188 | * Drain existing usages of @kn. Mutiple removers may invoke this function |
189 | * concurrently on @kn and all will return after draining is complete. | |
190 | * Returns %true if drain is performed and kernfs_mutex was temporarily | |
191 | * released. %false if @kn was already drained and no operation was | |
192 | * necessary. | |
193 | * | |
194 | * The caller is responsible for ensuring @kn stays pinned while this | |
195 | * function is in progress even if it gets removed by someone else. | |
fd7b9f7b | 196 | */ |
45a140e5 TH |
197 | static bool kernfs_drain(struct kernfs_node *kn) |
198 | __releases(&kernfs_mutex) __acquires(&kernfs_mutex) | |
fd7b9f7b | 199 | { |
ea1c472d | 200 | struct kernfs_root *root = kernfs_root(kn); |
fd7b9f7b | 201 | |
45a140e5 | 202 | lockdep_assert_held(&kernfs_mutex); |
ae34372e | 203 | WARN_ON_ONCE(atomic_read(&kn->active) >= 0); |
ea1c472d | 204 | |
45a140e5 TH |
205 | /* |
206 | * We want to go through the active ref lockdep annotation at least | |
207 | * once for all node removals, but the lockdep annotation can't be | |
208 | * nested inside kernfs_mutex and deactivation can't make forward | |
209 | * progress if we keep dropping the mutex. Use JUST_ACTIVATED to | |
210 | * force the slow path once for each deactivation if lockdep is | |
211 | * enabled. | |
212 | */ | |
213 | if ((!kernfs_lockdep(kn) || !(kn->flags & KERNFS_JUST_DEACTIVATED)) && | |
214 | atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) | |
215 | return false; | |
216 | ||
217 | kn->flags &= ~KERNFS_JUST_DEACTIVATED; | |
218 | mutex_unlock(&kernfs_mutex); | |
219 | ||
a69d001c TH |
220 | if (kernfs_lockdep(kn)) { |
221 | rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); | |
222 | if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) | |
223 | lock_contended(&kn->dep_map, _RET_IP_); | |
224 | } | |
ea1c472d TH |
225 | |
226 | wait_event(root->deactivate_waitq, | |
227 | atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); | |
fd7b9f7b | 228 | |
a69d001c TH |
229 | if (kernfs_lockdep(kn)) { |
230 | lock_acquired(&kn->dep_map, _RET_IP_); | |
231 | rwsem_release(&kn->dep_map, 1, _RET_IP_); | |
232 | } | |
45a140e5 TH |
233 | |
234 | mutex_lock(&kernfs_mutex); | |
235 | return true; | |
fd7b9f7b TH |
236 | } |
237 | ||
fd7b9f7b | 238 | /** |
324a56e1 TH |
239 | * kernfs_get - get a reference count on a kernfs_node |
240 | * @kn: the target kernfs_node | |
fd7b9f7b | 241 | */ |
324a56e1 | 242 | void kernfs_get(struct kernfs_node *kn) |
fd7b9f7b | 243 | { |
324a56e1 | 244 | if (kn) { |
adc5e8b5 TH |
245 | WARN_ON(!atomic_read(&kn->count)); |
246 | atomic_inc(&kn->count); | |
fd7b9f7b TH |
247 | } |
248 | } | |
249 | EXPORT_SYMBOL_GPL(kernfs_get); | |
250 | ||
251 | /** | |
324a56e1 TH |
252 | * kernfs_put - put a reference count on a kernfs_node |
253 | * @kn: the target kernfs_node | |
fd7b9f7b | 254 | * |
324a56e1 | 255 | * Put a reference count of @kn and destroy it if it reached zero. |
fd7b9f7b | 256 | */ |
324a56e1 | 257 | void kernfs_put(struct kernfs_node *kn) |
fd7b9f7b | 258 | { |
324a56e1 | 259 | struct kernfs_node *parent; |
ba7443bc | 260 | struct kernfs_root *root; |
fd7b9f7b | 261 | |
adc5e8b5 | 262 | if (!kn || !atomic_dec_and_test(&kn->count)) |
fd7b9f7b | 263 | return; |
324a56e1 | 264 | root = kernfs_root(kn); |
fd7b9f7b | 265 | repeat: |
ae34372e TH |
266 | /* |
267 | * Moving/renaming is always done while holding reference. | |
adc5e8b5 | 268 | * kn->parent won't change beneath us. |
fd7b9f7b | 269 | */ |
adc5e8b5 | 270 | parent = kn->parent; |
fd7b9f7b | 271 | |
ae34372e TH |
272 | WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, |
273 | "kernfs_put: %s/%s: released with incorrect active_ref %d\n", | |
274 | parent ? parent->name : "", kn->name, atomic_read(&kn->active)); | |
324a56e1 | 275 | |
df23fc39 | 276 | if (kernfs_type(kn) == KERNFS_LINK) |
adc5e8b5 | 277 | kernfs_put(kn->symlink.target_kn); |
2063d608 | 278 | if (!(kn->flags & KERNFS_STATIC_NAME)) |
adc5e8b5 TH |
279 | kfree(kn->name); |
280 | if (kn->iattr) { | |
281 | if (kn->iattr->ia_secdata) | |
282 | security_release_secctx(kn->iattr->ia_secdata, | |
283 | kn->iattr->ia_secdata_len); | |
284 | simple_xattrs_free(&kn->iattr->xattrs); | |
2322392b | 285 | } |
adc5e8b5 TH |
286 | kfree(kn->iattr); |
287 | ida_simple_remove(&root->ino_ida, kn->ino); | |
a797bfc3 | 288 | kmem_cache_free(kernfs_node_cache, kn); |
fd7b9f7b | 289 | |
324a56e1 TH |
290 | kn = parent; |
291 | if (kn) { | |
adc5e8b5 | 292 | if (atomic_dec_and_test(&kn->count)) |
ba7443bc TH |
293 | goto repeat; |
294 | } else { | |
324a56e1 | 295 | /* just released the root kn, free @root too */ |
bc755553 | 296 | ida_destroy(&root->ino_ida); |
ba7443bc TH |
297 | kfree(root); |
298 | } | |
fd7b9f7b TH |
299 | } |
300 | EXPORT_SYMBOL_GPL(kernfs_put); | |
301 | ||
c637b8ac | 302 | static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) |
fd7b9f7b | 303 | { |
324a56e1 | 304 | struct kernfs_node *kn; |
fd7b9f7b TH |
305 | |
306 | if (flags & LOOKUP_RCU) | |
307 | return -ECHILD; | |
308 | ||
19bbb926 TH |
309 | /* Always perform fresh lookup for negatives */ |
310 | if (!dentry->d_inode) | |
311 | goto out_bad_unlocked; | |
312 | ||
324a56e1 | 313 | kn = dentry->d_fsdata; |
a797bfc3 | 314 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 315 | |
ae34372e TH |
316 | /* Force fresh lookup if removed */ |
317 | if (kn->parent && RB_EMPTY_NODE(&kn->rb)) | |
fd7b9f7b TH |
318 | goto out_bad; |
319 | ||
c637b8ac | 320 | /* The kernfs node has been moved? */ |
adc5e8b5 | 321 | if (dentry->d_parent->d_fsdata != kn->parent) |
fd7b9f7b TH |
322 | goto out_bad; |
323 | ||
c637b8ac | 324 | /* The kernfs node has been renamed */ |
adc5e8b5 | 325 | if (strcmp(dentry->d_name.name, kn->name) != 0) |
fd7b9f7b TH |
326 | goto out_bad; |
327 | ||
c637b8ac | 328 | /* The kernfs node has been moved to a different namespace */ |
adc5e8b5 | 329 | if (kn->parent && kernfs_ns_enabled(kn->parent) && |
c525aadd | 330 | kernfs_info(dentry->d_sb)->ns != kn->ns) |
fd7b9f7b TH |
331 | goto out_bad; |
332 | ||
a797bfc3 | 333 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
334 | out_valid: |
335 | return 1; | |
336 | out_bad: | |
a797bfc3 | 337 | mutex_unlock(&kernfs_mutex); |
19bbb926 TH |
338 | out_bad_unlocked: |
339 | /* | |
340 | * @dentry doesn't match the underlying kernfs node, drop the | |
341 | * dentry and force lookup. If we have submounts we must allow the | |
342 | * vfs caches to lie about the state of the filesystem to prevent | |
343 | * leaks and other nasty things, so use check_submounts_and_drop() | |
344 | * instead of d_drop(). | |
fd7b9f7b TH |
345 | */ |
346 | if (check_submounts_and_drop(dentry) != 0) | |
347 | goto out_valid; | |
348 | ||
349 | return 0; | |
350 | } | |
351 | ||
c637b8ac | 352 | static void kernfs_dop_release(struct dentry *dentry) |
fd7b9f7b TH |
353 | { |
354 | kernfs_put(dentry->d_fsdata); | |
355 | } | |
356 | ||
a797bfc3 | 357 | const struct dentry_operations kernfs_dops = { |
c637b8ac | 358 | .d_revalidate = kernfs_dop_revalidate, |
c637b8ac | 359 | .d_release = kernfs_dop_release, |
fd7b9f7b TH |
360 | }; |
361 | ||
c637b8ac | 362 | struct kernfs_node *kernfs_new_node(struct kernfs_root *root, const char *name, |
2063d608 | 363 | umode_t mode, unsigned flags) |
fd7b9f7b TH |
364 | { |
365 | char *dup_name = NULL; | |
324a56e1 | 366 | struct kernfs_node *kn; |
bc755553 | 367 | int ret; |
fd7b9f7b | 368 | |
2063d608 | 369 | if (!(flags & KERNFS_STATIC_NAME)) { |
fd7b9f7b TH |
370 | name = dup_name = kstrdup(name, GFP_KERNEL); |
371 | if (!name) | |
372 | return NULL; | |
373 | } | |
374 | ||
a797bfc3 | 375 | kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); |
324a56e1 | 376 | if (!kn) |
fd7b9f7b TH |
377 | goto err_out1; |
378 | ||
bc755553 TH |
379 | ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL); |
380 | if (ret < 0) | |
fd7b9f7b | 381 | goto err_out2; |
adc5e8b5 | 382 | kn->ino = ret; |
fd7b9f7b | 383 | |
adc5e8b5 | 384 | atomic_set(&kn->count, 1); |
ae34372e TH |
385 | atomic_set(&kn->active, KN_DEACTIVATED_BIAS); |
386 | RB_CLEAR_NODE(&kn->rb); | |
fd7b9f7b | 387 | |
adc5e8b5 TH |
388 | kn->name = name; |
389 | kn->mode = mode; | |
ae34372e | 390 | kn->flags = flags; |
fd7b9f7b | 391 | |
324a56e1 | 392 | return kn; |
fd7b9f7b TH |
393 | |
394 | err_out2: | |
a797bfc3 | 395 | kmem_cache_free(kernfs_node_cache, kn); |
fd7b9f7b TH |
396 | err_out1: |
397 | kfree(dup_name); | |
398 | return NULL; | |
399 | } | |
400 | ||
fd7b9f7b | 401 | /** |
c637b8ac | 402 | * kernfs_add_one - add kernfs_node to parent without warning |
324a56e1 TH |
403 | * @kn: kernfs_node to be added |
404 | * @parent: the parent kernfs_node to add @kn to | |
fd7b9f7b | 405 | * |
adc5e8b5 TH |
406 | * Get @parent and set @kn->parent to it and increment nlink of the |
407 | * parent inode if @kn is a directory and link into the children list | |
408 | * of the parent. | |
fd7b9f7b | 409 | * |
fd7b9f7b TH |
410 | * RETURNS: |
411 | * 0 on success, -EEXIST if entry with the given name already | |
412 | * exists. | |
413 | */ | |
99177a34 | 414 | int kernfs_add_one(struct kernfs_node *kn, struct kernfs_node *parent) |
fd7b9f7b | 415 | { |
c525aadd | 416 | struct kernfs_iattrs *ps_iattr; |
99177a34 | 417 | bool has_ns; |
fd7b9f7b TH |
418 | int ret; |
419 | ||
99177a34 TH |
420 | if (!kernfs_get_active(parent)) |
421 | return -ENOENT; | |
ae34372e | 422 | |
99177a34 TH |
423 | mutex_lock(&kernfs_mutex); |
424 | ||
425 | ret = -EINVAL; | |
426 | has_ns = kernfs_ns_enabled(parent); | |
427 | if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", | |
428 | has_ns ? "required" : "invalid", parent->name, kn->name)) | |
429 | goto out_unlock; | |
fd7b9f7b | 430 | |
df23fc39 | 431 | if (kernfs_type(parent) != KERNFS_DIR) |
99177a34 | 432 | goto out_unlock; |
fd7b9f7b | 433 | |
c637b8ac | 434 | kn->hash = kernfs_name_hash(kn->name, kn->ns); |
adc5e8b5 | 435 | kn->parent = parent; |
324a56e1 | 436 | kernfs_get(parent); |
fd7b9f7b | 437 | |
c637b8ac | 438 | ret = kernfs_link_sibling(kn); |
fd7b9f7b | 439 | if (ret) |
99177a34 | 440 | goto out_unlock; |
fd7b9f7b TH |
441 | |
442 | /* Update timestamps on the parent */ | |
adc5e8b5 | 443 | ps_iattr = parent->iattr; |
fd7b9f7b TH |
444 | if (ps_iattr) { |
445 | struct iattr *ps_iattrs = &ps_iattr->ia_iattr; | |
446 | ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; | |
447 | } | |
448 | ||
449 | /* Mark the entry added into directory tree */ | |
ae34372e | 450 | atomic_sub(KN_DEACTIVATED_BIAS, &kn->active); |
99177a34 TH |
451 | ret = 0; |
452 | out_unlock: | |
a797bfc3 | 453 | mutex_unlock(&kernfs_mutex); |
99177a34 TH |
454 | kernfs_put_active(parent); |
455 | return ret; | |
fd7b9f7b TH |
456 | } |
457 | ||
458 | /** | |
324a56e1 TH |
459 | * kernfs_find_ns - find kernfs_node with the given name |
460 | * @parent: kernfs_node to search under | |
fd7b9f7b TH |
461 | * @name: name to look for |
462 | * @ns: the namespace tag to use | |
463 | * | |
324a56e1 TH |
464 | * Look for kernfs_node with name @name under @parent. Returns pointer to |
465 | * the found kernfs_node on success, %NULL on failure. | |
fd7b9f7b | 466 | */ |
324a56e1 TH |
467 | static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, |
468 | const unsigned char *name, | |
469 | const void *ns) | |
fd7b9f7b | 470 | { |
adc5e8b5 | 471 | struct rb_node *node = parent->dir.children.rb_node; |
ac9bba03 | 472 | bool has_ns = kernfs_ns_enabled(parent); |
fd7b9f7b TH |
473 | unsigned int hash; |
474 | ||
a797bfc3 | 475 | lockdep_assert_held(&kernfs_mutex); |
fd7b9f7b TH |
476 | |
477 | if (has_ns != (bool)ns) { | |
c637b8ac | 478 | WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", |
adc5e8b5 | 479 | has_ns ? "required" : "invalid", parent->name, name); |
fd7b9f7b TH |
480 | return NULL; |
481 | } | |
482 | ||
c637b8ac | 483 | hash = kernfs_name_hash(name, ns); |
fd7b9f7b | 484 | while (node) { |
324a56e1 | 485 | struct kernfs_node *kn; |
fd7b9f7b TH |
486 | int result; |
487 | ||
324a56e1 | 488 | kn = rb_to_kn(node); |
c637b8ac | 489 | result = kernfs_name_compare(hash, name, ns, kn); |
fd7b9f7b TH |
490 | if (result < 0) |
491 | node = node->rb_left; | |
492 | else if (result > 0) | |
493 | node = node->rb_right; | |
494 | else | |
324a56e1 | 495 | return kn; |
fd7b9f7b TH |
496 | } |
497 | return NULL; | |
498 | } | |
499 | ||
500 | /** | |
324a56e1 TH |
501 | * kernfs_find_and_get_ns - find and get kernfs_node with the given name |
502 | * @parent: kernfs_node to search under | |
fd7b9f7b TH |
503 | * @name: name to look for |
504 | * @ns: the namespace tag to use | |
505 | * | |
324a56e1 | 506 | * Look for kernfs_node with name @name under @parent and get a reference |
fd7b9f7b | 507 | * if found. This function may sleep and returns pointer to the found |
324a56e1 | 508 | * kernfs_node on success, %NULL on failure. |
fd7b9f7b | 509 | */ |
324a56e1 TH |
510 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
511 | const char *name, const void *ns) | |
fd7b9f7b | 512 | { |
324a56e1 | 513 | struct kernfs_node *kn; |
fd7b9f7b | 514 | |
a797bfc3 | 515 | mutex_lock(&kernfs_mutex); |
324a56e1 TH |
516 | kn = kernfs_find_ns(parent, name, ns); |
517 | kernfs_get(kn); | |
a797bfc3 | 518 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b | 519 | |
324a56e1 | 520 | return kn; |
fd7b9f7b TH |
521 | } |
522 | EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); | |
523 | ||
ba7443bc TH |
524 | /** |
525 | * kernfs_create_root - create a new kernfs hierarchy | |
80b9bbef | 526 | * @kdops: optional directory syscall operations for the hierarchy |
ba7443bc TH |
527 | * @priv: opaque data associated with the new directory |
528 | * | |
529 | * Returns the root of the new hierarchy on success, ERR_PTR() value on | |
530 | * failure. | |
531 | */ | |
80b9bbef | 532 | struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) |
ba7443bc TH |
533 | { |
534 | struct kernfs_root *root; | |
324a56e1 | 535 | struct kernfs_node *kn; |
ba7443bc TH |
536 | |
537 | root = kzalloc(sizeof(*root), GFP_KERNEL); | |
538 | if (!root) | |
539 | return ERR_PTR(-ENOMEM); | |
540 | ||
bc755553 TH |
541 | ida_init(&root->ino_ida); |
542 | ||
c637b8ac | 543 | kn = kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR); |
324a56e1 | 544 | if (!kn) { |
bc755553 | 545 | ida_destroy(&root->ino_ida); |
ba7443bc TH |
546 | kfree(root); |
547 | return ERR_PTR(-ENOMEM); | |
548 | } | |
549 | ||
ae34372e | 550 | atomic_sub(KN_DEACTIVATED_BIAS, &kn->active); |
324a56e1 | 551 | kn->priv = priv; |
adc5e8b5 | 552 | kn->dir.root = root; |
ba7443bc | 553 | |
80b9bbef | 554 | root->dir_ops = kdops; |
324a56e1 | 555 | root->kn = kn; |
ea1c472d | 556 | init_waitqueue_head(&root->deactivate_waitq); |
ba7443bc TH |
557 | |
558 | return root; | |
559 | } | |
560 | ||
561 | /** | |
562 | * kernfs_destroy_root - destroy a kernfs hierarchy | |
563 | * @root: root of the hierarchy to destroy | |
564 | * | |
565 | * Destroy the hierarchy anchored at @root by removing all existing | |
566 | * directories and destroying @root. | |
567 | */ | |
568 | void kernfs_destroy_root(struct kernfs_root *root) | |
569 | { | |
324a56e1 | 570 | kernfs_remove(root->kn); /* will also free @root */ |
ba7443bc TH |
571 | } |
572 | ||
fd7b9f7b TH |
573 | /** |
574 | * kernfs_create_dir_ns - create a directory | |
575 | * @parent: parent in which to create a new directory | |
576 | * @name: name of the new directory | |
bb8b9d09 | 577 | * @mode: mode of the new directory |
fd7b9f7b TH |
578 | * @priv: opaque data associated with the new directory |
579 | * @ns: optional namespace tag of the directory | |
580 | * | |
581 | * Returns the created node on success, ERR_PTR() value on failure. | |
582 | */ | |
324a56e1 | 583 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
bb8b9d09 TH |
584 | const char *name, umode_t mode, |
585 | void *priv, const void *ns) | |
fd7b9f7b | 586 | { |
324a56e1 | 587 | struct kernfs_node *kn; |
fd7b9f7b TH |
588 | int rc; |
589 | ||
590 | /* allocate */ | |
bb8b9d09 TH |
591 | kn = kernfs_new_node(kernfs_root(parent), name, mode | S_IFDIR, |
592 | KERNFS_DIR); | |
324a56e1 | 593 | if (!kn) |
fd7b9f7b TH |
594 | return ERR_PTR(-ENOMEM); |
595 | ||
adc5e8b5 TH |
596 | kn->dir.root = parent->dir.root; |
597 | kn->ns = ns; | |
324a56e1 | 598 | kn->priv = priv; |
fd7b9f7b TH |
599 | |
600 | /* link in */ | |
99177a34 | 601 | rc = kernfs_add_one(kn, parent); |
fd7b9f7b | 602 | if (!rc) |
324a56e1 | 603 | return kn; |
fd7b9f7b | 604 | |
324a56e1 | 605 | kernfs_put(kn); |
fd7b9f7b TH |
606 | return ERR_PTR(rc); |
607 | } | |
608 | ||
c637b8ac TH |
609 | static struct dentry *kernfs_iop_lookup(struct inode *dir, |
610 | struct dentry *dentry, | |
611 | unsigned int flags) | |
fd7b9f7b | 612 | { |
19bbb926 | 613 | struct dentry *ret; |
324a56e1 TH |
614 | struct kernfs_node *parent = dentry->d_parent->d_fsdata; |
615 | struct kernfs_node *kn; | |
fd7b9f7b TH |
616 | struct inode *inode; |
617 | const void *ns = NULL; | |
618 | ||
a797bfc3 | 619 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 620 | |
324a56e1 | 621 | if (kernfs_ns_enabled(parent)) |
c525aadd | 622 | ns = kernfs_info(dir->i_sb)->ns; |
fd7b9f7b | 623 | |
324a56e1 | 624 | kn = kernfs_find_ns(parent, dentry->d_name.name, ns); |
fd7b9f7b TH |
625 | |
626 | /* no such entry */ | |
324a56e1 | 627 | if (!kn) { |
19bbb926 | 628 | ret = NULL; |
fd7b9f7b TH |
629 | goto out_unlock; |
630 | } | |
324a56e1 TH |
631 | kernfs_get(kn); |
632 | dentry->d_fsdata = kn; | |
fd7b9f7b TH |
633 | |
634 | /* attach dentry and inode */ | |
c637b8ac | 635 | inode = kernfs_get_inode(dir->i_sb, kn); |
fd7b9f7b TH |
636 | if (!inode) { |
637 | ret = ERR_PTR(-ENOMEM); | |
638 | goto out_unlock; | |
639 | } | |
640 | ||
641 | /* instantiate and hash dentry */ | |
642 | ret = d_materialise_unique(dentry, inode); | |
643 | out_unlock: | |
a797bfc3 | 644 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
645 | return ret; |
646 | } | |
647 | ||
80b9bbef TH |
648 | static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, |
649 | umode_t mode) | |
650 | { | |
651 | struct kernfs_node *parent = dir->i_private; | |
652 | struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops; | |
653 | ||
654 | if (!kdops || !kdops->mkdir) | |
655 | return -EPERM; | |
656 | ||
657 | return kdops->mkdir(parent, dentry->d_name.name, mode); | |
658 | } | |
659 | ||
660 | static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) | |
661 | { | |
662 | struct kernfs_node *kn = dentry->d_fsdata; | |
663 | struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops; | |
664 | ||
665 | if (!kdops || !kdops->rmdir) | |
666 | return -EPERM; | |
667 | ||
668 | return kdops->rmdir(kn); | |
669 | } | |
670 | ||
671 | static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, | |
672 | struct inode *new_dir, struct dentry *new_dentry) | |
673 | { | |
674 | struct kernfs_node *kn = old_dentry->d_fsdata; | |
675 | struct kernfs_node *new_parent = new_dir->i_private; | |
676 | struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops; | |
677 | ||
678 | if (!kdops || !kdops->rename) | |
679 | return -EPERM; | |
680 | ||
681 | return kdops->rename(kn, new_parent, new_dentry->d_name.name); | |
682 | } | |
683 | ||
a797bfc3 | 684 | const struct inode_operations kernfs_dir_iops = { |
c637b8ac TH |
685 | .lookup = kernfs_iop_lookup, |
686 | .permission = kernfs_iop_permission, | |
687 | .setattr = kernfs_iop_setattr, | |
688 | .getattr = kernfs_iop_getattr, | |
689 | .setxattr = kernfs_iop_setxattr, | |
690 | .removexattr = kernfs_iop_removexattr, | |
691 | .getxattr = kernfs_iop_getxattr, | |
692 | .listxattr = kernfs_iop_listxattr, | |
80b9bbef TH |
693 | |
694 | .mkdir = kernfs_iop_mkdir, | |
695 | .rmdir = kernfs_iop_rmdir, | |
696 | .rename = kernfs_iop_rename, | |
fd7b9f7b TH |
697 | }; |
698 | ||
c637b8ac | 699 | static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) |
fd7b9f7b | 700 | { |
324a56e1 | 701 | struct kernfs_node *last; |
fd7b9f7b TH |
702 | |
703 | while (true) { | |
704 | struct rb_node *rbn; | |
705 | ||
706 | last = pos; | |
707 | ||
df23fc39 | 708 | if (kernfs_type(pos) != KERNFS_DIR) |
fd7b9f7b TH |
709 | break; |
710 | ||
adc5e8b5 | 711 | rbn = rb_first(&pos->dir.children); |
fd7b9f7b TH |
712 | if (!rbn) |
713 | break; | |
714 | ||
324a56e1 | 715 | pos = rb_to_kn(rbn); |
fd7b9f7b TH |
716 | } |
717 | ||
718 | return last; | |
719 | } | |
720 | ||
721 | /** | |
c637b8ac | 722 | * kernfs_next_descendant_post - find the next descendant for post-order walk |
fd7b9f7b | 723 | * @pos: the current position (%NULL to initiate traversal) |
324a56e1 | 724 | * @root: kernfs_node whose descendants to walk |
fd7b9f7b TH |
725 | * |
726 | * Find the next descendant to visit for post-order traversal of @root's | |
727 | * descendants. @root is included in the iteration and the last node to be | |
728 | * visited. | |
729 | */ | |
c637b8ac TH |
730 | static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, |
731 | struct kernfs_node *root) | |
fd7b9f7b TH |
732 | { |
733 | struct rb_node *rbn; | |
734 | ||
a797bfc3 | 735 | lockdep_assert_held(&kernfs_mutex); |
fd7b9f7b TH |
736 | |
737 | /* if first iteration, visit leftmost descendant which may be root */ | |
738 | if (!pos) | |
c637b8ac | 739 | return kernfs_leftmost_descendant(root); |
fd7b9f7b TH |
740 | |
741 | /* if we visited @root, we're done */ | |
742 | if (pos == root) | |
743 | return NULL; | |
744 | ||
745 | /* if there's an unvisited sibling, visit its leftmost descendant */ | |
adc5e8b5 | 746 | rbn = rb_next(&pos->rb); |
fd7b9f7b | 747 | if (rbn) |
c637b8ac | 748 | return kernfs_leftmost_descendant(rb_to_kn(rbn)); |
fd7b9f7b TH |
749 | |
750 | /* no sibling left, visit parent */ | |
adc5e8b5 | 751 | return pos->parent; |
fd7b9f7b TH |
752 | } |
753 | ||
45a140e5 TH |
754 | static void __kernfs_deactivate(struct kernfs_node *kn) |
755 | { | |
756 | struct kernfs_node *pos; | |
757 | ||
758 | lockdep_assert_held(&kernfs_mutex); | |
759 | ||
760 | /* prevent any new usage under @kn by deactivating all nodes */ | |
761 | pos = NULL; | |
762 | while ((pos = kernfs_next_descendant_post(pos, kn))) { | |
763 | if (atomic_read(&pos->active) >= 0) { | |
764 | atomic_add(KN_DEACTIVATED_BIAS, &pos->active); | |
765 | pos->flags |= KERNFS_JUST_DEACTIVATED; | |
766 | } | |
767 | } | |
768 | ||
769 | /* | |
770 | * Drain the subtree. If kernfs_drain() blocked to drain, which is | |
771 | * indicated by %true return, it temporarily released kernfs_mutex | |
772 | * and the rbtree might have been modified inbetween breaking our | |
773 | * future walk. Restart the walk after each %true return. | |
774 | */ | |
775 | pos = NULL; | |
776 | while ((pos = kernfs_next_descendant_post(pos, kn))) { | |
777 | bool drained; | |
778 | ||
779 | kernfs_get(pos); | |
780 | drained = kernfs_drain(pos); | |
781 | kernfs_put(pos); | |
782 | if (drained) | |
783 | pos = NULL; | |
784 | } | |
785 | } | |
786 | ||
99177a34 | 787 | static void __kernfs_remove(struct kernfs_node *kn) |
fd7b9f7b | 788 | { |
45a140e5 TH |
789 | struct kernfs_node *pos; |
790 | ||
791 | lockdep_assert_held(&kernfs_mutex); | |
fd7b9f7b | 792 | |
324a56e1 | 793 | if (!kn) |
fd7b9f7b TH |
794 | return; |
795 | ||
c637b8ac | 796 | pr_debug("kernfs %s: removing\n", kn->name); |
fd7b9f7b | 797 | |
45a140e5 TH |
798 | __kernfs_deactivate(kn); |
799 | ||
800 | /* unlink the subtree node-by-node */ | |
fd7b9f7b | 801 | do { |
45a140e5 TH |
802 | pos = kernfs_leftmost_descendant(kn); |
803 | ||
f601f9a2 TH |
804 | /* |
805 | * We're gonna release kernfs_mutex to unmap bin files, | |
806 | * Make sure @pos doesn't go away inbetween. | |
807 | */ | |
808 | kernfs_get(pos); | |
809 | ||
810 | /* | |
811 | * This must be come before unlinking; otherwise, when | |
812 | * there are multiple removers, some may finish before | |
813 | * unmapping is complete. | |
814 | */ | |
815 | if (pos->flags & KERNFS_HAS_MMAP) { | |
816 | mutex_unlock(&kernfs_mutex); | |
817 | kernfs_unmap_file(pos); | |
818 | mutex_lock(&kernfs_mutex); | |
819 | } | |
820 | ||
821 | /* | |
822 | * kernfs_unlink_sibling() succeeds once per node. Use it | |
823 | * to decide who's responsible for cleanups. | |
824 | */ | |
825 | if (!pos->parent || kernfs_unlink_sibling(pos)) { | |
826 | struct kernfs_iattrs *ps_iattr = | |
827 | pos->parent ? pos->parent->iattr : NULL; | |
45a140e5 TH |
828 | |
829 | /* update timestamps on the parent */ | |
45a140e5 TH |
830 | if (ps_iattr) { |
831 | ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; | |
832 | ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; | |
833 | } | |
f601f9a2 | 834 | |
99177a34 | 835 | kernfs_put(pos); |
45a140e5 TH |
836 | } |
837 | ||
f601f9a2 | 838 | kernfs_put(pos); |
45a140e5 | 839 | } while (pos != kn); |
fd7b9f7b TH |
840 | } |
841 | ||
842 | /** | |
324a56e1 TH |
843 | * kernfs_remove - remove a kernfs_node recursively |
844 | * @kn: the kernfs_node to remove | |
fd7b9f7b | 845 | * |
324a56e1 | 846 | * Remove @kn along with all its subdirectories and files. |
fd7b9f7b | 847 | */ |
324a56e1 | 848 | void kernfs_remove(struct kernfs_node *kn) |
fd7b9f7b | 849 | { |
99177a34 TH |
850 | mutex_lock(&kernfs_mutex); |
851 | __kernfs_remove(kn); | |
852 | mutex_unlock(&kernfs_mutex); | |
fd7b9f7b TH |
853 | } |
854 | ||
855 | /** | |
324a56e1 TH |
856 | * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it |
857 | * @parent: parent of the target | |
858 | * @name: name of the kernfs_node to remove | |
859 | * @ns: namespace tag of the kernfs_node to remove | |
fd7b9f7b | 860 | * |
324a56e1 TH |
861 | * Look for the kernfs_node with @name and @ns under @parent and remove it. |
862 | * Returns 0 on success, -ENOENT if such entry doesn't exist. | |
fd7b9f7b | 863 | */ |
324a56e1 | 864 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, |
fd7b9f7b TH |
865 | const void *ns) |
866 | { | |
324a56e1 | 867 | struct kernfs_node *kn; |
fd7b9f7b | 868 | |
324a56e1 | 869 | if (!parent) { |
c637b8ac | 870 | WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", |
fd7b9f7b TH |
871 | name); |
872 | return -ENOENT; | |
873 | } | |
874 | ||
99177a34 | 875 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 876 | |
324a56e1 TH |
877 | kn = kernfs_find_ns(parent, name, ns); |
878 | if (kn) | |
99177a34 | 879 | __kernfs_remove(kn); |
fd7b9f7b | 880 | |
99177a34 | 881 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b | 882 | |
324a56e1 | 883 | if (kn) |
fd7b9f7b TH |
884 | return 0; |
885 | else | |
886 | return -ENOENT; | |
887 | } | |
888 | ||
889 | /** | |
890 | * kernfs_rename_ns - move and rename a kernfs_node | |
324a56e1 | 891 | * @kn: target node |
fd7b9f7b TH |
892 | * @new_parent: new parent to put @sd under |
893 | * @new_name: new name | |
894 | * @new_ns: new namespace tag | |
895 | */ | |
324a56e1 | 896 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
fd7b9f7b TH |
897 | const char *new_name, const void *new_ns) |
898 | { | |
899 | int error; | |
900 | ||
d0ae3d43 | 901 | error = -ENOENT; |
ae34372e | 902 | if (!kernfs_get_active(new_parent)) |
d0ae3d43 | 903 | goto out; |
ae34372e TH |
904 | if (!kernfs_get_active(kn)) |
905 | goto out_put_new_parent; | |
906 | ||
907 | mutex_lock(&kernfs_mutex); | |
d0ae3d43 | 908 | |
fd7b9f7b | 909 | error = 0; |
adc5e8b5 TH |
910 | if ((kn->parent == new_parent) && (kn->ns == new_ns) && |
911 | (strcmp(kn->name, new_name) == 0)) | |
ae34372e | 912 | goto out_unlock; /* nothing to rename */ |
fd7b9f7b TH |
913 | |
914 | error = -EEXIST; | |
915 | if (kernfs_find_ns(new_parent, new_name, new_ns)) | |
ae34372e | 916 | goto out_unlock; |
fd7b9f7b | 917 | |
324a56e1 | 918 | /* rename kernfs_node */ |
adc5e8b5 | 919 | if (strcmp(kn->name, new_name) != 0) { |
fd7b9f7b TH |
920 | error = -ENOMEM; |
921 | new_name = kstrdup(new_name, GFP_KERNEL); | |
922 | if (!new_name) | |
ae34372e | 923 | goto out_unlock; |
fd7b9f7b | 924 | |
47a52e91 TH |
925 | if (kn->flags & KERNFS_STATIC_NAME) |
926 | kn->flags &= ~KERNFS_STATIC_NAME; | |
927 | else | |
928 | kfree(kn->name); | |
929 | ||
adc5e8b5 | 930 | kn->name = new_name; |
fd7b9f7b TH |
931 | } |
932 | ||
933 | /* | |
934 | * Move to the appropriate place in the appropriate directories rbtree. | |
935 | */ | |
c637b8ac | 936 | kernfs_unlink_sibling(kn); |
fd7b9f7b | 937 | kernfs_get(new_parent); |
adc5e8b5 TH |
938 | kernfs_put(kn->parent); |
939 | kn->ns = new_ns; | |
c637b8ac | 940 | kn->hash = kernfs_name_hash(kn->name, kn->ns); |
adc5e8b5 | 941 | kn->parent = new_parent; |
c637b8ac | 942 | kernfs_link_sibling(kn); |
fd7b9f7b TH |
943 | |
944 | error = 0; | |
ae34372e | 945 | out_unlock: |
a797bfc3 | 946 | mutex_unlock(&kernfs_mutex); |
ae34372e TH |
947 | kernfs_put_active(kn); |
948 | out_put_new_parent: | |
949 | kernfs_put_active(new_parent); | |
950 | out: | |
fd7b9f7b TH |
951 | return error; |
952 | } | |
953 | ||
fd7b9f7b | 954 | /* Relationship between s_mode and the DT_xxx types */ |
324a56e1 | 955 | static inline unsigned char dt_type(struct kernfs_node *kn) |
fd7b9f7b | 956 | { |
adc5e8b5 | 957 | return (kn->mode >> 12) & 15; |
fd7b9f7b TH |
958 | } |
959 | ||
c637b8ac | 960 | static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) |
fd7b9f7b TH |
961 | { |
962 | kernfs_put(filp->private_data); | |
963 | return 0; | |
964 | } | |
965 | ||
c637b8ac | 966 | static struct kernfs_node *kernfs_dir_pos(const void *ns, |
324a56e1 | 967 | struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) |
fd7b9f7b TH |
968 | { |
969 | if (pos) { | |
ae34372e | 970 | int valid = pos->parent == parent && hash == pos->hash; |
fd7b9f7b TH |
971 | kernfs_put(pos); |
972 | if (!valid) | |
973 | pos = NULL; | |
974 | } | |
975 | if (!pos && (hash > 1) && (hash < INT_MAX)) { | |
adc5e8b5 | 976 | struct rb_node *node = parent->dir.children.rb_node; |
fd7b9f7b | 977 | while (node) { |
324a56e1 | 978 | pos = rb_to_kn(node); |
fd7b9f7b | 979 | |
adc5e8b5 | 980 | if (hash < pos->hash) |
fd7b9f7b | 981 | node = node->rb_left; |
adc5e8b5 | 982 | else if (hash > pos->hash) |
fd7b9f7b TH |
983 | node = node->rb_right; |
984 | else | |
985 | break; | |
986 | } | |
987 | } | |
988 | /* Skip over entries in the wrong namespace */ | |
adc5e8b5 TH |
989 | while (pos && pos->ns != ns) { |
990 | struct rb_node *node = rb_next(&pos->rb); | |
fd7b9f7b TH |
991 | if (!node) |
992 | pos = NULL; | |
993 | else | |
324a56e1 | 994 | pos = rb_to_kn(node); |
fd7b9f7b TH |
995 | } |
996 | return pos; | |
997 | } | |
998 | ||
c637b8ac | 999 | static struct kernfs_node *kernfs_dir_next_pos(const void *ns, |
324a56e1 | 1000 | struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) |
fd7b9f7b | 1001 | { |
c637b8ac | 1002 | pos = kernfs_dir_pos(ns, parent, ino, pos); |
fd7b9f7b TH |
1003 | if (pos) |
1004 | do { | |
adc5e8b5 | 1005 | struct rb_node *node = rb_next(&pos->rb); |
fd7b9f7b TH |
1006 | if (!node) |
1007 | pos = NULL; | |
1008 | else | |
324a56e1 | 1009 | pos = rb_to_kn(node); |
adc5e8b5 | 1010 | } while (pos && pos->ns != ns); |
fd7b9f7b TH |
1011 | return pos; |
1012 | } | |
1013 | ||
c637b8ac | 1014 | static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) |
fd7b9f7b TH |
1015 | { |
1016 | struct dentry *dentry = file->f_path.dentry; | |
324a56e1 TH |
1017 | struct kernfs_node *parent = dentry->d_fsdata; |
1018 | struct kernfs_node *pos = file->private_data; | |
fd7b9f7b TH |
1019 | const void *ns = NULL; |
1020 | ||
1021 | if (!dir_emit_dots(file, ctx)) | |
1022 | return 0; | |
a797bfc3 | 1023 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 1024 | |
324a56e1 | 1025 | if (kernfs_ns_enabled(parent)) |
c525aadd | 1026 | ns = kernfs_info(dentry->d_sb)->ns; |
fd7b9f7b | 1027 | |
c637b8ac | 1028 | for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); |
fd7b9f7b | 1029 | pos; |
c637b8ac | 1030 | pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { |
adc5e8b5 | 1031 | const char *name = pos->name; |
fd7b9f7b TH |
1032 | unsigned int type = dt_type(pos); |
1033 | int len = strlen(name); | |
adc5e8b5 | 1034 | ino_t ino = pos->ino; |
fd7b9f7b | 1035 | |
adc5e8b5 | 1036 | ctx->pos = pos->hash; |
fd7b9f7b TH |
1037 | file->private_data = pos; |
1038 | kernfs_get(pos); | |
1039 | ||
a797bfc3 | 1040 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
1041 | if (!dir_emit(ctx, name, len, ino, type)) |
1042 | return 0; | |
a797bfc3 | 1043 | mutex_lock(&kernfs_mutex); |
fd7b9f7b | 1044 | } |
a797bfc3 | 1045 | mutex_unlock(&kernfs_mutex); |
fd7b9f7b TH |
1046 | file->private_data = NULL; |
1047 | ctx->pos = INT_MAX; | |
1048 | return 0; | |
1049 | } | |
1050 | ||
c637b8ac TH |
1051 | static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset, |
1052 | int whence) | |
fd7b9f7b TH |
1053 | { |
1054 | struct inode *inode = file_inode(file); | |
1055 | loff_t ret; | |
1056 | ||
1057 | mutex_lock(&inode->i_mutex); | |
1058 | ret = generic_file_llseek(file, offset, whence); | |
1059 | mutex_unlock(&inode->i_mutex); | |
1060 | ||
1061 | return ret; | |
1062 | } | |
1063 | ||
a797bfc3 | 1064 | const struct file_operations kernfs_dir_fops = { |
fd7b9f7b | 1065 | .read = generic_read_dir, |
c637b8ac TH |
1066 | .iterate = kernfs_fop_readdir, |
1067 | .release = kernfs_dir_fop_release, | |
1068 | .llseek = kernfs_dir_fop_llseek, | |
fd7b9f7b | 1069 | }; |