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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * dir.c - Operations for sysfs directories. | |
3 | */ | |
4 | ||
5 | #undef DEBUG | |
6 | ||
7 | #include <linux/fs.h> | |
8 | #include <linux/mount.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/kobject.h> | |
5f45f1a7 | 11 | #include <linux/namei.h> |
2b611bb7 | 12 | #include <linux/idr.h> |
8619f979 | 13 | #include <linux/completion.h> |
94bebf4d | 14 | #include <asm/semaphore.h> |
1da177e4 LT |
15 | #include "sysfs.h" |
16 | ||
3007e997 | 17 | DEFINE_MUTEX(sysfs_mutex); |
5f995323 | 18 | spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED; |
1da177e4 | 19 | |
2b611bb7 TH |
20 | static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED; |
21 | static DEFINE_IDA(sysfs_ino_ida); | |
22 | ||
0c73f18b TH |
23 | /** |
24 | * sysfs_link_sibling - link sysfs_dirent into sibling list | |
25 | * @sd: sysfs_dirent of interest | |
26 | * | |
27 | * Link @sd into its sibling list which starts from | |
28 | * sd->s_parent->s_children. | |
29 | * | |
30 | * Locking: | |
3007e997 | 31 | * mutex_lock(sysfs_mutex) |
0c73f18b | 32 | */ |
fb6896da | 33 | void sysfs_link_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
34 | { |
35 | struct sysfs_dirent *parent_sd = sd->s_parent; | |
36 | ||
37 | BUG_ON(sd->s_sibling); | |
38 | sd->s_sibling = parent_sd->s_children; | |
39 | parent_sd->s_children = sd; | |
40 | } | |
41 | ||
42 | /** | |
43 | * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list | |
44 | * @sd: sysfs_dirent of interest | |
45 | * | |
46 | * Unlink @sd from its sibling list which starts from | |
47 | * sd->s_parent->s_children. | |
48 | * | |
49 | * Locking: | |
3007e997 | 50 | * mutex_lock(sysfs_mutex) |
0c73f18b | 51 | */ |
fb6896da | 52 | void sysfs_unlink_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
53 | { |
54 | struct sysfs_dirent **pos; | |
55 | ||
56 | for (pos = &sd->s_parent->s_children; *pos; pos = &(*pos)->s_sibling) { | |
57 | if (*pos == sd) { | |
58 | *pos = sd->s_sibling; | |
59 | sd->s_sibling = NULL; | |
60 | break; | |
61 | } | |
62 | } | |
63 | } | |
64 | ||
53e0ae92 TH |
65 | /** |
66 | * sysfs_get_dentry - get dentry for the given sysfs_dirent | |
67 | * @sd: sysfs_dirent of interest | |
68 | * | |
69 | * Get dentry for @sd. Dentry is looked up if currently not | |
70 | * present. This function climbs sysfs_dirent tree till it | |
71 | * reaches a sysfs_dirent with valid dentry attached and descends | |
72 | * down from there looking up dentry for each step. | |
73 | * | |
74 | * LOCKING: | |
75 | * Kernel thread context (may sleep) | |
76 | * | |
77 | * RETURNS: | |
78 | * Pointer to found dentry on success, ERR_PTR() value on error. | |
79 | */ | |
80 | struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd) | |
81 | { | |
82 | struct sysfs_dirent *cur; | |
83 | struct dentry *parent_dentry, *dentry; | |
84 | int i, depth; | |
85 | ||
86 | /* Find the first parent which has valid s_dentry and get the | |
87 | * dentry. | |
88 | */ | |
89 | mutex_lock(&sysfs_mutex); | |
90 | restart0: | |
91 | spin_lock(&sysfs_assoc_lock); | |
92 | restart1: | |
93 | spin_lock(&dcache_lock); | |
94 | ||
95 | dentry = NULL; | |
96 | depth = 0; | |
97 | cur = sd; | |
98 | while (!cur->s_dentry || !cur->s_dentry->d_inode) { | |
99 | if (cur->s_flags & SYSFS_FLAG_REMOVED) { | |
100 | dentry = ERR_PTR(-ENOENT); | |
101 | depth = 0; | |
102 | break; | |
103 | } | |
104 | cur = cur->s_parent; | |
105 | depth++; | |
106 | } | |
107 | if (!IS_ERR(dentry)) | |
108 | dentry = dget_locked(cur->s_dentry); | |
109 | ||
110 | spin_unlock(&dcache_lock); | |
111 | spin_unlock(&sysfs_assoc_lock); | |
112 | ||
113 | /* from the found dentry, look up depth times */ | |
114 | while (depth--) { | |
115 | /* find and get depth'th ancestor */ | |
116 | for (cur = sd, i = 0; cur && i < depth; i++) | |
117 | cur = cur->s_parent; | |
118 | ||
119 | /* This can happen if tree structure was modified due | |
120 | * to move/rename. Restart. | |
121 | */ | |
122 | if (i != depth) { | |
123 | dput(dentry); | |
124 | goto restart0; | |
125 | } | |
126 | ||
127 | sysfs_get(cur); | |
128 | ||
129 | mutex_unlock(&sysfs_mutex); | |
130 | ||
131 | /* look it up */ | |
132 | parent_dentry = dentry; | |
133 | dentry = lookup_one_len_kern(cur->s_name, parent_dentry, | |
134 | strlen(cur->s_name)); | |
135 | dput(parent_dentry); | |
136 | ||
137 | if (IS_ERR(dentry)) { | |
138 | sysfs_put(cur); | |
139 | return dentry; | |
140 | } | |
141 | ||
142 | mutex_lock(&sysfs_mutex); | |
143 | spin_lock(&sysfs_assoc_lock); | |
144 | ||
145 | /* This, again, can happen if tree structure has | |
146 | * changed and we looked up the wrong thing. Restart. | |
147 | */ | |
148 | if (cur->s_dentry != dentry) { | |
149 | dput(dentry); | |
150 | sysfs_put(cur); | |
151 | goto restart1; | |
152 | } | |
153 | ||
154 | spin_unlock(&sysfs_assoc_lock); | |
155 | ||
156 | sysfs_put(cur); | |
157 | } | |
158 | ||
159 | mutex_unlock(&sysfs_mutex); | |
160 | return dentry; | |
161 | } | |
162 | ||
b6b4a439 TH |
163 | /** |
164 | * sysfs_get_active - get an active reference to sysfs_dirent | |
165 | * @sd: sysfs_dirent to get an active reference to | |
166 | * | |
167 | * Get an active reference of @sd. This function is noop if @sd | |
168 | * is NULL. | |
169 | * | |
170 | * RETURNS: | |
171 | * Pointer to @sd on success, NULL on failure. | |
172 | */ | |
173 | struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) | |
174 | { | |
8619f979 TH |
175 | if (unlikely(!sd)) |
176 | return NULL; | |
177 | ||
178 | while (1) { | |
179 | int v, t; | |
180 | ||
181 | v = atomic_read(&sd->s_active); | |
182 | if (unlikely(v < 0)) | |
183 | return NULL; | |
184 | ||
185 | t = atomic_cmpxchg(&sd->s_active, v, v + 1); | |
186 | if (likely(t == v)) | |
187 | return sd; | |
188 | if (t < 0) | |
189 | return NULL; | |
190 | ||
191 | cpu_relax(); | |
b6b4a439 | 192 | } |
b6b4a439 TH |
193 | } |
194 | ||
195 | /** | |
196 | * sysfs_put_active - put an active reference to sysfs_dirent | |
197 | * @sd: sysfs_dirent to put an active reference to | |
198 | * | |
199 | * Put an active reference to @sd. This function is noop if @sd | |
200 | * is NULL. | |
201 | */ | |
202 | void sysfs_put_active(struct sysfs_dirent *sd) | |
203 | { | |
8619f979 TH |
204 | struct completion *cmpl; |
205 | int v; | |
206 | ||
207 | if (unlikely(!sd)) | |
208 | return; | |
209 | ||
210 | v = atomic_dec_return(&sd->s_active); | |
211 | if (likely(v != SD_DEACTIVATED_BIAS)) | |
212 | return; | |
213 | ||
214 | /* atomic_dec_return() is a mb(), we'll always see the updated | |
0c73f18b | 215 | * sd->s_sibling. |
8619f979 | 216 | */ |
0c73f18b | 217 | cmpl = (void *)sd->s_sibling; |
8619f979 | 218 | complete(cmpl); |
b6b4a439 TH |
219 | } |
220 | ||
221 | /** | |
222 | * sysfs_get_active_two - get active references to sysfs_dirent and parent | |
223 | * @sd: sysfs_dirent of interest | |
224 | * | |
225 | * Get active reference to @sd and its parent. Parent's active | |
226 | * reference is grabbed first. This function is noop if @sd is | |
227 | * NULL. | |
228 | * | |
229 | * RETURNS: | |
230 | * Pointer to @sd on success, NULL on failure. | |
231 | */ | |
232 | struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) | |
233 | { | |
234 | if (sd) { | |
235 | if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) | |
236 | return NULL; | |
237 | if (unlikely(!sysfs_get_active(sd))) { | |
238 | sysfs_put_active(sd->s_parent); | |
239 | return NULL; | |
240 | } | |
241 | } | |
242 | return sd; | |
243 | } | |
244 | ||
245 | /** | |
246 | * sysfs_put_active_two - put active references to sysfs_dirent and parent | |
247 | * @sd: sysfs_dirent of interest | |
248 | * | |
249 | * Put active references to @sd and its parent. This function is | |
250 | * noop if @sd is NULL. | |
251 | */ | |
252 | void sysfs_put_active_two(struct sysfs_dirent *sd) | |
253 | { | |
254 | if (sd) { | |
255 | sysfs_put_active(sd); | |
256 | sysfs_put_active(sd->s_parent); | |
257 | } | |
258 | } | |
259 | ||
260 | /** | |
261 | * sysfs_deactivate - deactivate sysfs_dirent | |
262 | * @sd: sysfs_dirent to deactivate | |
263 | * | |
8619f979 | 264 | * Deny new active references and drain existing ones. |
b6b4a439 | 265 | */ |
fb6896da | 266 | static void sysfs_deactivate(struct sysfs_dirent *sd) |
b6b4a439 | 267 | { |
8619f979 TH |
268 | DECLARE_COMPLETION_ONSTACK(wait); |
269 | int v; | |
b6b4a439 | 270 | |
380e6fbb | 271 | BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
0c73f18b | 272 | sd->s_sibling = (void *)&wait; |
8619f979 TH |
273 | |
274 | /* atomic_add_return() is a mb(), put_active() will always see | |
0c73f18b | 275 | * the updated sd->s_sibling. |
b6b4a439 | 276 | */ |
8619f979 TH |
277 | v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
278 | ||
279 | if (v != SD_DEACTIVATED_BIAS) | |
280 | wait_for_completion(&wait); | |
281 | ||
0c73f18b | 282 | sd->s_sibling = NULL; |
b6b4a439 TH |
283 | } |
284 | ||
42b37df6 | 285 | static int sysfs_alloc_ino(ino_t *pino) |
2b611bb7 TH |
286 | { |
287 | int ino, rc; | |
288 | ||
289 | retry: | |
290 | spin_lock(&sysfs_ino_lock); | |
291 | rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); | |
292 | spin_unlock(&sysfs_ino_lock); | |
293 | ||
294 | if (rc == -EAGAIN) { | |
295 | if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) | |
296 | goto retry; | |
297 | rc = -ENOMEM; | |
298 | } | |
299 | ||
300 | *pino = ino; | |
301 | return rc; | |
302 | } | |
303 | ||
304 | static void sysfs_free_ino(ino_t ino) | |
305 | { | |
306 | spin_lock(&sysfs_ino_lock); | |
307 | ida_remove(&sysfs_ino_ida, ino); | |
308 | spin_unlock(&sysfs_ino_lock); | |
309 | } | |
310 | ||
fa7f912a TH |
311 | void release_sysfs_dirent(struct sysfs_dirent * sd) |
312 | { | |
13b3086d TH |
313 | struct sysfs_dirent *parent_sd; |
314 | ||
315 | repeat: | |
3007e997 TH |
316 | /* Moving/renaming is always done while holding reference. |
317 | * sd->s_parent won't change beneath us. | |
318 | */ | |
13b3086d TH |
319 | parent_sd = sd->s_parent; |
320 | ||
b402d72c | 321 | if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
2b29ac25 | 322 | sysfs_put(sd->s_elem.symlink.target_sd); |
b402d72c | 323 | if (sysfs_type(sd) & SYSFS_COPY_NAME) |
0c096b50 | 324 | kfree(sd->s_name); |
fa7f912a | 325 | kfree(sd->s_iattr); |
2b611bb7 | 326 | sysfs_free_ino(sd->s_ino); |
fa7f912a | 327 | kmem_cache_free(sysfs_dir_cachep, sd); |
13b3086d TH |
328 | |
329 | sd = parent_sd; | |
330 | if (sd && atomic_dec_and_test(&sd->s_count)) | |
331 | goto repeat; | |
fa7f912a TH |
332 | } |
333 | ||
1da177e4 LT |
334 | static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) |
335 | { | |
336 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
337 | ||
338 | if (sd) { | |
5f995323 TH |
339 | /* sd->s_dentry is protected with sysfs_assoc_lock. |
340 | * This allows sysfs_drop_dentry() to dereference it. | |
dd14cbc9 | 341 | */ |
5f995323 | 342 | spin_lock(&sysfs_assoc_lock); |
dd14cbc9 TH |
343 | |
344 | /* The dentry might have been deleted or another | |
345 | * lookup could have happened updating sd->s_dentry to | |
346 | * point the new dentry. Ignore if it isn't pointing | |
347 | * to this dentry. | |
348 | */ | |
349 | if (sd->s_dentry == dentry) | |
350 | sd->s_dentry = NULL; | |
5f995323 | 351 | spin_unlock(&sysfs_assoc_lock); |
1da177e4 LT |
352 | sysfs_put(sd); |
353 | } | |
354 | iput(inode); | |
355 | } | |
356 | ||
357 | static struct dentry_operations sysfs_dentry_ops = { | |
358 | .d_iput = sysfs_d_iput, | |
359 | }; | |
360 | ||
3e519038 | 361 | struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
1da177e4 | 362 | { |
0c096b50 TH |
363 | char *dup_name = NULL; |
364 | struct sysfs_dirent *sd = NULL; | |
365 | ||
366 | if (type & SYSFS_COPY_NAME) { | |
367 | name = dup_name = kstrdup(name, GFP_KERNEL); | |
368 | if (!name) | |
369 | goto err_out; | |
370 | } | |
1da177e4 | 371 | |
c3762229 | 372 | sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
1da177e4 | 373 | if (!sd) |
0c096b50 | 374 | goto err_out; |
1da177e4 | 375 | |
0c096b50 TH |
376 | if (sysfs_alloc_ino(&sd->s_ino)) |
377 | goto err_out; | |
2b611bb7 | 378 | |
1da177e4 | 379 | atomic_set(&sd->s_count, 1); |
8619f979 | 380 | atomic_set(&sd->s_active, 0); |
eea3f891 | 381 | atomic_set(&sd->s_event, 1); |
a26cd722 | 382 | |
0c096b50 | 383 | sd->s_name = name; |
a26cd722 | 384 | sd->s_mode = mode; |
b402d72c | 385 | sd->s_flags = type; |
1da177e4 LT |
386 | |
387 | return sd; | |
0c096b50 TH |
388 | |
389 | err_out: | |
390 | kfree(dup_name); | |
391 | kmem_cache_free(sysfs_dir_cachep, sd); | |
392 | return NULL; | |
1da177e4 LT |
393 | } |
394 | ||
3007e997 TH |
395 | /** |
396 | * sysfs_attach_dentry - associate sysfs_dirent with dentry | |
397 | * @sd: target sysfs_dirent | |
398 | * @dentry: dentry to associate | |
399 | * | |
400 | * Associate @sd with @dentry. This is protected by | |
401 | * sysfs_assoc_lock to avoid race with sysfs_d_iput(). | |
402 | * | |
403 | * LOCKING: | |
404 | * mutex_lock(sysfs_mutex) | |
405 | */ | |
198a2a84 TH |
406 | static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) |
407 | { | |
408 | dentry->d_op = &sysfs_dentry_ops; | |
409 | dentry->d_fsdata = sysfs_get(sd); | |
410 | ||
411 | /* protect sd->s_dentry against sysfs_d_iput */ | |
5f995323 | 412 | spin_lock(&sysfs_assoc_lock); |
198a2a84 | 413 | sd->s_dentry = dentry; |
5f995323 | 414 | spin_unlock(&sysfs_assoc_lock); |
198a2a84 TH |
415 | |
416 | d_rehash(dentry); | |
417 | } | |
418 | ||
fb6896da TH |
419 | static int sysfs_ilookup_test(struct inode *inode, void *arg) |
420 | { | |
421 | struct sysfs_dirent *sd = arg; | |
422 | return inode->i_ino == sd->s_ino; | |
423 | } | |
424 | ||
3007e997 | 425 | /** |
fb6896da TH |
426 | * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
427 | * @acxt: pointer to sysfs_addrm_cxt to be used | |
428 | * @parent_sd: parent sysfs_dirent | |
3007e997 | 429 | * |
fb6896da TH |
430 | * This function is called when the caller is about to add or |
431 | * remove sysfs_dirent under @parent_sd. This function acquires | |
432 | * sysfs_mutex, grabs inode for @parent_sd if available and lock | |
433 | * i_mutex of it. @acxt is used to keep and pass context to | |
434 | * other addrm functions. | |
3007e997 TH |
435 | * |
436 | * LOCKING: | |
fb6896da TH |
437 | * Kernel thread context (may sleep). sysfs_mutex is locked on |
438 | * return. i_mutex of parent inode is locked on return if | |
439 | * available. | |
3007e997 | 440 | */ |
fb6896da TH |
441 | void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
442 | struct sysfs_dirent *parent_sd) | |
b592fcfe | 443 | { |
fb6896da | 444 | struct inode *inode; |
b592fcfe | 445 | |
fb6896da TH |
446 | memset(acxt, 0, sizeof(*acxt)); |
447 | acxt->parent_sd = parent_sd; | |
448 | ||
449 | /* Lookup parent inode. inode initialization and I_NEW | |
450 | * clearing are protected by sysfs_mutex. By grabbing it and | |
451 | * looking up with _nowait variant, inode state can be | |
452 | * determined reliably. | |
453 | */ | |
454 | mutex_lock(&sysfs_mutex); | |
455 | ||
456 | inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test, | |
457 | parent_sd); | |
458 | ||
459 | if (inode && !(inode->i_state & I_NEW)) { | |
460 | /* parent inode available */ | |
461 | acxt->parent_inode = inode; | |
462 | ||
463 | /* sysfs_mutex is below i_mutex in lock hierarchy. | |
464 | * First, trylock i_mutex. If fails, unlock | |
465 | * sysfs_mutex and lock them in order. | |
466 | */ | |
467 | if (!mutex_trylock(&inode->i_mutex)) { | |
468 | mutex_unlock(&sysfs_mutex); | |
469 | mutex_lock(&inode->i_mutex); | |
470 | mutex_lock(&sysfs_mutex); | |
471 | } | |
472 | } else | |
473 | iput(inode); | |
474 | } | |
475 | ||
476 | /** | |
477 | * sysfs_add_one - add sysfs_dirent to parent | |
478 | * @acxt: addrm context to use | |
479 | * @sd: sysfs_dirent to be added | |
480 | * | |
481 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
482 | * nlink of parent inode if @sd is a directory. @sd is NOT | |
483 | * linked into the children list of the parent. The caller | |
484 | * should invoke sysfs_link_sibling() after this function | |
485 | * completes if @sd needs to be on the children list. | |
486 | * | |
487 | * This function should be called between calls to | |
488 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
489 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
490 | * | |
491 | * LOCKING: | |
492 | * Determined by sysfs_addrm_start(). | |
493 | */ | |
494 | void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
495 | { | |
496 | sd->s_parent = sysfs_get(acxt->parent_sd); | |
497 | ||
498 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
499 | inc_nlink(acxt->parent_inode); | |
500 | ||
501 | acxt->cnt++; | |
502 | } | |
503 | ||
504 | /** | |
505 | * sysfs_remove_one - remove sysfs_dirent from parent | |
506 | * @acxt: addrm context to use | |
507 | * @sd: sysfs_dirent to be added | |
508 | * | |
509 | * Mark @sd removed and drop nlink of parent inode if @sd is a | |
510 | * directory. @sd is NOT unlinked from the children list of the | |
511 | * parent. The caller is repsonsible for removing @sd from the | |
512 | * children list before calling this function. | |
513 | * | |
514 | * This function should be called between calls to | |
515 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
516 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
517 | * | |
518 | * LOCKING: | |
519 | * Determined by sysfs_addrm_start(). | |
520 | */ | |
521 | void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
522 | { | |
523 | BUG_ON(sd->s_sibling || (sd->s_flags & SYSFS_FLAG_REMOVED)); | |
524 | ||
525 | sd->s_flags |= SYSFS_FLAG_REMOVED; | |
526 | sd->s_sibling = acxt->removed; | |
527 | acxt->removed = sd; | |
528 | ||
529 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
530 | drop_nlink(acxt->parent_inode); | |
531 | ||
532 | acxt->cnt++; | |
533 | } | |
534 | ||
a0edd7c8 TH |
535 | /** |
536 | * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent | |
537 | * @sd: target sysfs_dirent | |
538 | * | |
539 | * Drop dentry for @sd. @sd must have been unlinked from its | |
540 | * parent on entry to this function such that it can't be looked | |
541 | * up anymore. | |
542 | * | |
543 | * @sd->s_dentry which is protected with sysfs_assoc_lock points | |
544 | * to the currently associated dentry but we're not holding a | |
545 | * reference to it and racing with dput(). Grab dcache_lock and | |
546 | * verify dentry before dropping it. If @sd->s_dentry is NULL or | |
547 | * dput() beats us, no need to bother. | |
548 | */ | |
549 | static void sysfs_drop_dentry(struct sysfs_dirent *sd) | |
550 | { | |
551 | struct dentry *dentry = NULL; | |
552 | struct inode *inode; | |
553 | ||
554 | /* We're not holding a reference to ->s_dentry dentry but the | |
555 | * field will stay valid as long as sysfs_assoc_lock is held. | |
556 | */ | |
557 | spin_lock(&sysfs_assoc_lock); | |
558 | spin_lock(&dcache_lock); | |
559 | ||
560 | /* drop dentry if it's there and dput() didn't kill it yet */ | |
561 | if (sd->s_dentry && sd->s_dentry->d_inode) { | |
562 | dentry = dget_locked(sd->s_dentry); | |
563 | spin_lock(&dentry->d_lock); | |
564 | __d_drop(dentry); | |
565 | spin_unlock(&dentry->d_lock); | |
566 | } | |
567 | ||
568 | spin_unlock(&dcache_lock); | |
569 | spin_unlock(&sysfs_assoc_lock); | |
570 | ||
51225039 TH |
571 | /* dentries for shadowed inodes are pinned, unpin */ |
572 | if (dentry && sysfs_is_shadowed_inode(dentry->d_inode)) | |
a0edd7c8 | 573 | dput(dentry); |
51225039 | 574 | dput(dentry); |
a0edd7c8 TH |
575 | |
576 | /* adjust nlink and update timestamp */ | |
577 | inode = ilookup(sysfs_sb, sd->s_ino); | |
578 | if (inode) { | |
579 | mutex_lock(&inode->i_mutex); | |
580 | ||
581 | inode->i_ctime = CURRENT_TIME; | |
582 | drop_nlink(inode); | |
583 | if (sysfs_type(sd) == SYSFS_DIR) | |
584 | drop_nlink(inode); | |
585 | ||
586 | mutex_unlock(&inode->i_mutex); | |
587 | iput(inode); | |
588 | } | |
589 | } | |
590 | ||
fb6896da TH |
591 | /** |
592 | * sysfs_addrm_finish - finish up sysfs_dirent add/remove | |
593 | * @acxt: addrm context to finish up | |
594 | * | |
595 | * Finish up sysfs_dirent add/remove. Resources acquired by | |
596 | * sysfs_addrm_start() are released and removed sysfs_dirents are | |
597 | * cleaned up. Timestamps on the parent inode are updated. | |
598 | * | |
599 | * LOCKING: | |
600 | * All mutexes acquired by sysfs_addrm_start() are released. | |
601 | * | |
602 | * RETURNS: | |
603 | * Number of added/removed sysfs_dirents since sysfs_addrm_start(). | |
604 | */ | |
605 | int sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) | |
606 | { | |
607 | /* release resources acquired by sysfs_addrm_start() */ | |
608 | mutex_unlock(&sysfs_mutex); | |
609 | if (acxt->parent_inode) { | |
610 | struct inode *inode = acxt->parent_inode; | |
611 | ||
612 | /* if added/removed, update timestamps on the parent */ | |
613 | if (acxt->cnt) | |
614 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
615 | ||
616 | mutex_unlock(&inode->i_mutex); | |
617 | iput(inode); | |
618 | } | |
619 | ||
620 | /* kill removed sysfs_dirents */ | |
621 | while (acxt->removed) { | |
622 | struct sysfs_dirent *sd = acxt->removed; | |
623 | ||
624 | acxt->removed = sd->s_sibling; | |
625 | sd->s_sibling = NULL; | |
626 | ||
627 | sysfs_drop_dentry(sd); | |
628 | sysfs_deactivate(sd); | |
629 | sysfs_put(sd); | |
13b3086d | 630 | } |
fb6896da TH |
631 | |
632 | return acxt->cnt; | |
b592fcfe EB |
633 | } |
634 | ||
f0b0af47 TH |
635 | /** |
636 | * sysfs_find_dirent - find sysfs_dirent with the given name | |
637 | * @parent_sd: sysfs_dirent to search under | |
638 | * @name: name to look for | |
639 | * | |
640 | * Look for sysfs_dirent with name @name under @parent_sd. | |
c516865c | 641 | * |
f0b0af47 | 642 | * LOCKING: |
3007e997 | 643 | * mutex_lock(sysfs_mutex) |
c516865c | 644 | * |
f0b0af47 TH |
645 | * RETURNS: |
646 | * Pointer to sysfs_dirent if found, NULL if not. | |
c516865c | 647 | */ |
f0b0af47 TH |
648 | struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, |
649 | const unsigned char *name) | |
c516865c | 650 | { |
f0b0af47 TH |
651 | struct sysfs_dirent *sd; |
652 | ||
653 | for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) | |
654 | if (sysfs_type(sd) && !strcmp(sd->s_name, name)) | |
655 | return sd; | |
656 | return NULL; | |
657 | } | |
c516865c | 658 | |
f0b0af47 TH |
659 | /** |
660 | * sysfs_get_dirent - find and get sysfs_dirent with the given name | |
661 | * @parent_sd: sysfs_dirent to search under | |
662 | * @name: name to look for | |
663 | * | |
664 | * Look for sysfs_dirent with name @name under @parent_sd and get | |
665 | * it if found. | |
666 | * | |
667 | * LOCKING: | |
3007e997 | 668 | * Kernel thread context (may sleep). Grabs sysfs_mutex. |
f0b0af47 TH |
669 | * |
670 | * RETURNS: | |
671 | * Pointer to sysfs_dirent if found, NULL if not. | |
672 | */ | |
673 | struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, | |
674 | const unsigned char *name) | |
675 | { | |
676 | struct sysfs_dirent *sd; | |
677 | ||
3007e997 | 678 | mutex_lock(&sysfs_mutex); |
f0b0af47 TH |
679 | sd = sysfs_find_dirent(parent_sd, name); |
680 | sysfs_get(sd); | |
3007e997 | 681 | mutex_unlock(&sysfs_mutex); |
f0b0af47 TH |
682 | |
683 | return sd; | |
c516865c MS |
684 | } |
685 | ||
608e266a TH |
686 | static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
687 | const char *name, struct sysfs_dirent **p_sd) | |
1da177e4 | 688 | { |
1da177e4 | 689 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
51225039 | 690 | struct sysfs_addrm_cxt acxt; |
dfeb9fb0 | 691 | struct sysfs_dirent *sd; |
1da177e4 | 692 | |
fc9f54b9 | 693 | /* allocate */ |
3e519038 | 694 | sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
a26cd722 | 695 | if (!sd) |
51225039 | 696 | return -ENOMEM; |
3e519038 | 697 | sd->s_elem.dir.kobj = kobj; |
dfeb9fb0 | 698 | |
fc9f54b9 | 699 | /* link in */ |
51225039 TH |
700 | sysfs_addrm_start(&acxt, parent_sd); |
701 | if (!sysfs_find_dirent(parent_sd, name)) { | |
702 | sysfs_add_one(&acxt, sd); | |
703 | sysfs_link_sibling(sd); | |
704 | } | |
705 | if (sysfs_addrm_finish(&acxt)) { | |
706 | *p_sd = sd; | |
707 | return 0; | |
708 | } | |
dfeb9fb0 | 709 | |
dfeb9fb0 | 710 | sysfs_put(sd); |
51225039 | 711 | return -EEXIST; |
1da177e4 LT |
712 | } |
713 | ||
608e266a TH |
714 | int sysfs_create_subdir(struct kobject *kobj, const char *name, |
715 | struct sysfs_dirent **p_sd) | |
1da177e4 | 716 | { |
608e266a | 717 | return create_dir(kobj, kobj->sd, name, p_sd); |
1da177e4 LT |
718 | } |
719 | ||
720 | /** | |
721 | * sysfs_create_dir - create a directory for an object. | |
1da177e4 | 722 | * @kobj: object we're creating directory for. |
608e266a | 723 | * @shadow_parent: parent object. |
1da177e4 | 724 | */ |
608e266a TH |
725 | int sysfs_create_dir(struct kobject *kobj, |
726 | struct sysfs_dirent *shadow_parent_sd) | |
1da177e4 | 727 | { |
608e266a | 728 | struct sysfs_dirent *parent_sd, *sd; |
1da177e4 LT |
729 | int error = 0; |
730 | ||
731 | BUG_ON(!kobj); | |
732 | ||
608e266a TH |
733 | if (shadow_parent_sd) |
734 | parent_sd = shadow_parent_sd; | |
b592fcfe | 735 | else if (kobj->parent) |
608e266a | 736 | parent_sd = kobj->parent->sd; |
1da177e4 | 737 | else if (sysfs_mount && sysfs_mount->mnt_sb) |
608e266a | 738 | parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata; |
1da177e4 LT |
739 | else |
740 | return -EFAULT; | |
741 | ||
608e266a | 742 | error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd); |
1da177e4 | 743 | if (!error) |
608e266a | 744 | kobj->sd = sd; |
1da177e4 LT |
745 | return error; |
746 | } | |
747 | ||
51225039 TH |
748 | static int sysfs_count_nlink(struct sysfs_dirent *sd) |
749 | { | |
750 | struct sysfs_dirent *child; | |
751 | int nr = 0; | |
752 | ||
753 | for (child = sd->s_children; child; child = child->s_sibling) | |
754 | if (sysfs_type(child) == SYSFS_DIR) | |
755 | nr++; | |
756 | return nr + 2; | |
757 | } | |
758 | ||
1da177e4 LT |
759 | static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
760 | struct nameidata *nd) | |
761 | { | |
762 | struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
763 | struct sysfs_dirent * sd; | |
b402d72c | 764 | struct bin_attribute *bin_attr; |
fc9f54b9 TH |
765 | struct inode *inode; |
766 | int found = 0; | |
1da177e4 | 767 | |
0c73f18b | 768 | for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) { |
51225039 | 769 | if (sysfs_type(sd) && |
fc9f54b9 TH |
770 | !strcmp(sd->s_name, dentry->d_name.name)) { |
771 | found = 1; | |
1da177e4 LT |
772 | break; |
773 | } | |
774 | } | |
775 | ||
fc9f54b9 TH |
776 | /* no such entry */ |
777 | if (!found) | |
778 | return NULL; | |
779 | ||
780 | /* attach dentry and inode */ | |
8312a8d7 | 781 | inode = sysfs_get_inode(sd); |
fc9f54b9 TH |
782 | if (!inode) |
783 | return ERR_PTR(-ENOMEM); | |
784 | ||
3007e997 TH |
785 | mutex_lock(&sysfs_mutex); |
786 | ||
8312a8d7 TH |
787 | if (inode->i_state & I_NEW) { |
788 | /* initialize inode according to type */ | |
b402d72c | 789 | switch (sysfs_type(sd)) { |
51225039 TH |
790 | case SYSFS_DIR: |
791 | inode->i_op = &sysfs_dir_inode_operations; | |
792 | inode->i_fop = &sysfs_dir_operations; | |
793 | inode->i_nlink = sysfs_count_nlink(sd); | |
794 | break; | |
b402d72c | 795 | case SYSFS_KOBJ_ATTR: |
8312a8d7 TH |
796 | inode->i_size = PAGE_SIZE; |
797 | inode->i_fop = &sysfs_file_operations; | |
b402d72c TH |
798 | break; |
799 | case SYSFS_KOBJ_BIN_ATTR: | |
800 | bin_attr = sd->s_elem.bin_attr.bin_attr; | |
8312a8d7 TH |
801 | inode->i_size = bin_attr->size; |
802 | inode->i_fop = &bin_fops; | |
b402d72c TH |
803 | break; |
804 | case SYSFS_KOBJ_LINK: | |
8312a8d7 | 805 | inode->i_op = &sysfs_symlink_inode_operations; |
b402d72c TH |
806 | break; |
807 | default: | |
808 | BUG(); | |
809 | } | |
8312a8d7 | 810 | } |
fc9f54b9 TH |
811 | |
812 | sysfs_instantiate(dentry, inode); | |
813 | sysfs_attach_dentry(sd, dentry); | |
814 | ||
3007e997 TH |
815 | mutex_unlock(&sysfs_mutex); |
816 | ||
fc9f54b9 | 817 | return NULL; |
1da177e4 LT |
818 | } |
819 | ||
c5ef1c42 | 820 | const struct inode_operations sysfs_dir_inode_operations = { |
1da177e4 | 821 | .lookup = sysfs_lookup, |
988d186d | 822 | .setattr = sysfs_setattr, |
1da177e4 LT |
823 | }; |
824 | ||
608e266a | 825 | static void remove_dir(struct sysfs_dirent *sd) |
1da177e4 | 826 | { |
fb6896da | 827 | struct sysfs_addrm_cxt acxt; |
1da177e4 | 828 | |
fb6896da TH |
829 | sysfs_addrm_start(&acxt, sd->s_parent); |
830 | sysfs_unlink_sibling(sd); | |
831 | sysfs_remove_one(&acxt, sd); | |
832 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
833 | } |
834 | ||
608e266a | 835 | void sysfs_remove_subdir(struct sysfs_dirent *sd) |
1da177e4 | 836 | { |
608e266a | 837 | remove_dir(sd); |
1da177e4 LT |
838 | } |
839 | ||
840 | ||
608e266a | 841 | static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
1da177e4 | 842 | { |
fb6896da | 843 | struct sysfs_addrm_cxt acxt; |
0c73f18b | 844 | struct sysfs_dirent **pos; |
1da177e4 | 845 | |
608e266a | 846 | if (!dir_sd) |
1da177e4 LT |
847 | return; |
848 | ||
608e266a | 849 | pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
fb6896da | 850 | sysfs_addrm_start(&acxt, dir_sd); |
608e266a | 851 | pos = &dir_sd->s_children; |
0c73f18b TH |
852 | while (*pos) { |
853 | struct sysfs_dirent *sd = *pos; | |
854 | ||
51225039 | 855 | if (sysfs_type(sd) && sysfs_type(sd) != SYSFS_DIR) { |
0c73f18b | 856 | *pos = sd->s_sibling; |
fb6896da TH |
857 | sd->s_sibling = NULL; |
858 | sysfs_remove_one(&acxt, sd); | |
0c73f18b TH |
859 | } else |
860 | pos = &(*pos)->s_sibling; | |
1da177e4 | 861 | } |
fb6896da | 862 | sysfs_addrm_finish(&acxt); |
0ab66088 | 863 | |
608e266a | 864 | remove_dir(dir_sd); |
b592fcfe EB |
865 | } |
866 | ||
867 | /** | |
868 | * sysfs_remove_dir - remove an object's directory. | |
869 | * @kobj: object. | |
870 | * | |
871 | * The only thing special about this is that we remove any files in | |
872 | * the directory before we remove the directory, and we've inlined | |
873 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
874 | */ | |
875 | ||
876 | void sysfs_remove_dir(struct kobject * kobj) | |
877 | { | |
608e266a | 878 | struct sysfs_dirent *sd = kobj->sd; |
aecdceda | 879 | |
5f995323 | 880 | spin_lock(&sysfs_assoc_lock); |
608e266a | 881 | kobj->sd = NULL; |
5f995323 | 882 | spin_unlock(&sysfs_assoc_lock); |
aecdceda | 883 | |
608e266a | 884 | __sysfs_remove_dir(sd); |
1da177e4 LT |
885 | } |
886 | ||
608e266a | 887 | int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, |
b592fcfe | 888 | const char *new_name) |
1da177e4 | 889 | { |
608e266a | 890 | struct sysfs_dirent *sd = kobj->sd; |
51225039 TH |
891 | struct dentry *new_parent = NULL; |
892 | struct dentry *old_dentry = NULL, *new_dentry = NULL; | |
893 | const char *dup_name = NULL; | |
996b7376 | 894 | int error; |
1da177e4 | 895 | |
51225039 TH |
896 | /* get dentries */ |
897 | old_dentry = sysfs_get_dentry(sd); | |
898 | if (IS_ERR(old_dentry)) { | |
899 | error = PTR_ERR(old_dentry); | |
900 | goto out_dput; | |
901 | } | |
902 | ||
903 | new_parent = sysfs_get_dentry(new_parent_sd); | |
904 | if (IS_ERR(new_parent)) { | |
905 | error = PTR_ERR(new_parent); | |
906 | goto out_dput; | |
907 | } | |
1da177e4 | 908 | |
51225039 | 909 | /* lock new_parent and get dentry for new name */ |
b592fcfe | 910 | mutex_lock(&new_parent->d_inode->i_mutex); |
1da177e4 | 911 | |
b592fcfe | 912 | new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); |
996b7376 TH |
913 | if (IS_ERR(new_dentry)) { |
914 | error = PTR_ERR(new_dentry); | |
915 | goto out_unlock; | |
1da177e4 | 916 | } |
996b7376 TH |
917 | |
918 | /* By allowing two different directories with the same | |
919 | * d_parent we allow this routine to move between different | |
920 | * shadows of the same directory | |
921 | */ | |
922 | error = -EINVAL; | |
51225039 | 923 | if (old_dentry->d_parent->d_inode != new_parent->d_inode || |
996b7376 | 924 | new_dentry->d_parent->d_inode != new_parent->d_inode || |
51225039 TH |
925 | old_dentry == new_dentry) |
926 | goto out_unlock; | |
996b7376 TH |
927 | |
928 | error = -EEXIST; | |
929 | if (new_dentry->d_inode) | |
51225039 | 930 | goto out_unlock; |
996b7376 | 931 | |
0c096b50 TH |
932 | /* rename kobject and sysfs_dirent */ |
933 | error = -ENOMEM; | |
934 | new_name = dup_name = kstrdup(new_name, GFP_KERNEL); | |
935 | if (!new_name) | |
936 | goto out_drop; | |
937 | ||
996b7376 TH |
938 | error = kobject_set_name(kobj, "%s", new_name); |
939 | if (error) | |
51225039 | 940 | goto out_drop; |
996b7376 | 941 | |
51225039 | 942 | dup_name = sd->s_name; |
0c096b50 TH |
943 | sd->s_name = new_name; |
944 | ||
945 | /* move under the new parent */ | |
996b7376 | 946 | d_add(new_dentry, NULL); |
608e266a | 947 | d_move(sd->s_dentry, new_dentry); |
996b7376 | 948 | |
3007e997 TH |
949 | mutex_lock(&sysfs_mutex); |
950 | ||
0c73f18b | 951 | sysfs_unlink_sibling(sd); |
608e266a | 952 | sysfs_get(new_parent_sd); |
7f7cfffe | 953 | sysfs_put(sd->s_parent); |
608e266a | 954 | sd->s_parent = new_parent_sd; |
0c73f18b | 955 | sysfs_link_sibling(sd); |
996b7376 | 956 | |
3007e997 TH |
957 | mutex_unlock(&sysfs_mutex); |
958 | ||
996b7376 TH |
959 | error = 0; |
960 | goto out_unlock; | |
961 | ||
962 | out_drop: | |
963 | d_drop(new_dentry); | |
996b7376 | 964 | out_unlock: |
b592fcfe | 965 | mutex_unlock(&new_parent->d_inode->i_mutex); |
51225039 TH |
966 | out_dput: |
967 | kfree(dup_name); | |
968 | dput(new_parent); | |
969 | dput(old_dentry); | |
970 | dput(new_dentry); | |
1da177e4 LT |
971 | return error; |
972 | } | |
973 | ||
51225039 | 974 | int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) |
8a82472f | 975 | { |
51225039 TH |
976 | struct sysfs_dirent *sd = kobj->sd; |
977 | struct sysfs_dirent *new_parent_sd; | |
978 | struct dentry *old_parent, *new_parent = NULL; | |
979 | struct dentry *old_dentry = NULL, *new_dentry = NULL; | |
8a82472f CH |
980 | int error; |
981 | ||
51225039 TH |
982 | BUG_ON(!sd->s_parent); |
983 | new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root; | |
984 | ||
985 | /* get dentries */ | |
986 | old_dentry = sysfs_get_dentry(sd); | |
987 | if (IS_ERR(old_dentry)) { | |
988 | error = PTR_ERR(old_dentry); | |
989 | goto out_dput; | |
990 | } | |
991 | old_parent = sd->s_parent->s_dentry; | |
992 | ||
993 | new_parent = sysfs_get_dentry(new_parent_sd); | |
994 | if (IS_ERR(new_parent)) { | |
995 | error = PTR_ERR(new_parent); | |
996 | goto out_dput; | |
997 | } | |
8a82472f | 998 | |
51225039 TH |
999 | if (old_parent->d_inode == new_parent->d_inode) { |
1000 | error = 0; | |
1001 | goto out_dput; /* nothing to move */ | |
1002 | } | |
8a82472f | 1003 | again: |
51225039 TH |
1004 | mutex_lock(&old_parent->d_inode->i_mutex); |
1005 | if (!mutex_trylock(&new_parent->d_inode->i_mutex)) { | |
1006 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
8a82472f CH |
1007 | goto again; |
1008 | } | |
1009 | ||
51225039 | 1010 | new_dentry = lookup_one_len(kobj->name, new_parent, strlen(kobj->name)); |
8a82472f CH |
1011 | if (IS_ERR(new_dentry)) { |
1012 | error = PTR_ERR(new_dentry); | |
51225039 | 1013 | goto out_unlock; |
8a82472f CH |
1014 | } else |
1015 | error = 0; | |
1016 | d_add(new_dentry, NULL); | |
608e266a | 1017 | d_move(sd->s_dentry, new_dentry); |
8a82472f CH |
1018 | dput(new_dentry); |
1019 | ||
1020 | /* Remove from old parent's list and insert into new parent's list. */ | |
3007e997 TH |
1021 | mutex_lock(&sysfs_mutex); |
1022 | ||
0c73f18b | 1023 | sysfs_unlink_sibling(sd); |
7f7cfffe TH |
1024 | sysfs_get(new_parent_sd); |
1025 | sysfs_put(sd->s_parent); | |
1026 | sd->s_parent = new_parent_sd; | |
0c73f18b | 1027 | sysfs_link_sibling(sd); |
8a82472f | 1028 | |
3007e997 | 1029 | mutex_unlock(&sysfs_mutex); |
8a82472f | 1030 | |
51225039 TH |
1031 | out_unlock: |
1032 | mutex_unlock(&new_parent->d_inode->i_mutex); | |
1033 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
1034 | out_dput: | |
1035 | dput(new_parent); | |
1036 | dput(old_dentry); | |
1037 | dput(new_dentry); | |
8a82472f CH |
1038 | return error; |
1039 | } | |
1040 | ||
1da177e4 LT |
1041 | static int sysfs_dir_open(struct inode *inode, struct file *file) |
1042 | { | |
f427f5d5 | 1043 | struct dentry * dentry = file->f_path.dentry; |
1da177e4 | 1044 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
a26cd722 | 1045 | struct sysfs_dirent * sd; |
1da177e4 | 1046 | |
3e519038 | 1047 | sd = sysfs_new_dirent("_DIR_", 0, 0); |
3007e997 TH |
1048 | if (sd) { |
1049 | mutex_lock(&sysfs_mutex); | |
fb6896da TH |
1050 | sd->s_parent = sysfs_get(parent_sd); |
1051 | sysfs_link_sibling(sd); | |
3007e997 TH |
1052 | mutex_unlock(&sysfs_mutex); |
1053 | } | |
1da177e4 | 1054 | |
a26cd722 TH |
1055 | file->private_data = sd; |
1056 | return sd ? 0 : -ENOMEM; | |
1da177e4 LT |
1057 | } |
1058 | ||
1059 | static int sysfs_dir_close(struct inode *inode, struct file *file) | |
1060 | { | |
1da177e4 LT |
1061 | struct sysfs_dirent * cursor = file->private_data; |
1062 | ||
3007e997 | 1063 | mutex_lock(&sysfs_mutex); |
0c73f18b | 1064 | sysfs_unlink_sibling(cursor); |
3007e997 | 1065 | mutex_unlock(&sysfs_mutex); |
1da177e4 LT |
1066 | |
1067 | release_sysfs_dirent(cursor); | |
1068 | ||
1069 | return 0; | |
1070 | } | |
1071 | ||
1072 | /* Relationship between s_mode and the DT_xxx types */ | |
1073 | static inline unsigned char dt_type(struct sysfs_dirent *sd) | |
1074 | { | |
1075 | return (sd->s_mode >> 12) & 15; | |
1076 | } | |
1077 | ||
1078 | static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1079 | { | |
f427f5d5 | 1080 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 LT |
1081 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
1082 | struct sysfs_dirent *cursor = filp->private_data; | |
0c73f18b | 1083 | struct sysfs_dirent **pos; |
1da177e4 LT |
1084 | ino_t ino; |
1085 | int i = filp->f_pos; | |
1086 | ||
1087 | switch (i) { | |
1088 | case 0: | |
dc351252 | 1089 | ino = parent_sd->s_ino; |
1da177e4 LT |
1090 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) |
1091 | break; | |
1092 | filp->f_pos++; | |
1093 | i++; | |
1094 | /* fallthrough */ | |
1095 | case 1: | |
13b3086d TH |
1096 | if (parent_sd->s_parent) |
1097 | ino = parent_sd->s_parent->s_ino; | |
1098 | else | |
1099 | ino = parent_sd->s_ino; | |
1da177e4 LT |
1100 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) |
1101 | break; | |
1102 | filp->f_pos++; | |
1103 | i++; | |
1104 | /* fallthrough */ | |
1105 | default: | |
3007e997 TH |
1106 | mutex_lock(&sysfs_mutex); |
1107 | ||
0c73f18b TH |
1108 | pos = &parent_sd->s_children; |
1109 | while (*pos != cursor) | |
1110 | pos = &(*pos)->s_sibling; | |
1111 | ||
1112 | /* unlink cursor */ | |
1113 | *pos = cursor->s_sibling; | |
1114 | ||
1bfba4e8 | 1115 | if (filp->f_pos == 2) |
0c73f18b | 1116 | pos = &parent_sd->s_children; |
1bfba4e8 | 1117 | |
0c73f18b TH |
1118 | for ( ; *pos; pos = &(*pos)->s_sibling) { |
1119 | struct sysfs_dirent *next = *pos; | |
1da177e4 LT |
1120 | const char * name; |
1121 | int len; | |
1122 | ||
b402d72c | 1123 | if (!sysfs_type(next)) |
1da177e4 LT |
1124 | continue; |
1125 | ||
0c096b50 | 1126 | name = next->s_name; |
1da177e4 | 1127 | len = strlen(name); |
dc351252 | 1128 | ino = next->s_ino; |
1da177e4 LT |
1129 | |
1130 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1131 | dt_type(next)) < 0) | |
0c73f18b | 1132 | break; |
1da177e4 | 1133 | |
1da177e4 LT |
1134 | filp->f_pos++; |
1135 | } | |
0c73f18b TH |
1136 | |
1137 | /* put cursor back in */ | |
1138 | cursor->s_sibling = *pos; | |
1139 | *pos = cursor; | |
3007e997 TH |
1140 | |
1141 | mutex_unlock(&sysfs_mutex); | |
1da177e4 LT |
1142 | } |
1143 | return 0; | |
1144 | } | |
1145 | ||
1146 | static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) | |
1147 | { | |
f427f5d5 | 1148 | struct dentry * dentry = file->f_path.dentry; |
1da177e4 | 1149 | |
1da177e4 LT |
1150 | switch (origin) { |
1151 | case 1: | |
1152 | offset += file->f_pos; | |
1153 | case 0: | |
1154 | if (offset >= 0) | |
1155 | break; | |
1156 | default: | |
1da177e4 LT |
1157 | return -EINVAL; |
1158 | } | |
1159 | if (offset != file->f_pos) { | |
3007e997 TH |
1160 | mutex_lock(&sysfs_mutex); |
1161 | ||
1da177e4 LT |
1162 | file->f_pos = offset; |
1163 | if (file->f_pos >= 2) { | |
1164 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
1165 | struct sysfs_dirent *cursor = file->private_data; | |
0c73f18b | 1166 | struct sysfs_dirent **pos; |
1da177e4 LT |
1167 | loff_t n = file->f_pos - 2; |
1168 | ||
0c73f18b TH |
1169 | sysfs_unlink_sibling(cursor); |
1170 | ||
1171 | pos = &sd->s_children; | |
1172 | while (n && *pos) { | |
1173 | struct sysfs_dirent *next = *pos; | |
b402d72c | 1174 | if (sysfs_type(next)) |
1da177e4 | 1175 | n--; |
0c73f18b | 1176 | pos = &(*pos)->s_sibling; |
1da177e4 | 1177 | } |
0c73f18b TH |
1178 | |
1179 | cursor->s_sibling = *pos; | |
1180 | *pos = cursor; | |
1da177e4 | 1181 | } |
3007e997 TH |
1182 | |
1183 | mutex_unlock(&sysfs_mutex); | |
1da177e4 | 1184 | } |
3007e997 | 1185 | |
1da177e4 LT |
1186 | return offset; |
1187 | } | |
1188 | ||
b592fcfe EB |
1189 | |
1190 | /** | |
1191 | * sysfs_make_shadowed_dir - Setup so a directory can be shadowed | |
1192 | * @kobj: object we're creating shadow of. | |
1193 | */ | |
1194 | ||
1195 | int sysfs_make_shadowed_dir(struct kobject *kobj, | |
1196 | void * (*follow_link)(struct dentry *, struct nameidata *)) | |
1197 | { | |
51225039 | 1198 | struct dentry *dentry; |
b592fcfe EB |
1199 | struct inode *inode; |
1200 | struct inode_operations *i_op; | |
1201 | ||
51225039 TH |
1202 | /* get dentry for @kobj->sd, dentry of a shadowed dir is pinned */ |
1203 | dentry = sysfs_get_dentry(kobj->sd); | |
1204 | if (IS_ERR(dentry)) | |
1205 | return PTR_ERR(dentry); | |
1206 | ||
1207 | inode = dentry->d_inode; | |
1208 | if (inode->i_op != &sysfs_dir_inode_operations) { | |
1209 | dput(dentry); | |
b592fcfe | 1210 | return -EINVAL; |
51225039 | 1211 | } |
b592fcfe EB |
1212 | |
1213 | i_op = kmalloc(sizeof(*i_op), GFP_KERNEL); | |
1214 | if (!i_op) | |
1215 | return -ENOMEM; | |
1216 | ||
1217 | memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op)); | |
1218 | i_op->follow_link = follow_link; | |
1219 | ||
1220 | /* Locking of inode->i_op? | |
1221 | * Since setting i_op is a single word write and they | |
1222 | * are atomic we should be ok here. | |
1223 | */ | |
1224 | inode->i_op = i_op; | |
1225 | return 0; | |
1226 | } | |
1227 | ||
1228 | /** | |
1229 | * sysfs_create_shadow_dir - create a shadow directory for an object. | |
1230 | * @kobj: object we're creating directory for. | |
1231 | * | |
1232 | * sysfs_make_shadowed_dir must already have been called on this | |
1233 | * directory. | |
1234 | */ | |
1235 | ||
608e266a | 1236 | struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj) |
b592fcfe | 1237 | { |
51225039 TH |
1238 | struct sysfs_dirent *parent_sd = kobj->sd->s_parent; |
1239 | struct dentry *dir, *parent, *shadow; | |
1240 | struct inode *inode; | |
b592fcfe | 1241 | struct sysfs_dirent *sd; |
fb6896da | 1242 | struct sysfs_addrm_cxt acxt; |
b592fcfe | 1243 | |
51225039 TH |
1244 | dir = sysfs_get_dentry(kobj->sd); |
1245 | if (IS_ERR(dir)) { | |
1246 | sd = (void *)dir; | |
1247 | goto out; | |
1248 | } | |
1249 | parent = dir->d_parent; | |
1250 | ||
1251 | inode = dir->d_inode; | |
608e266a | 1252 | sd = ERR_PTR(-EINVAL); |
b592fcfe | 1253 | if (!sysfs_is_shadowed_inode(inode)) |
51225039 | 1254 | goto out_dput; |
b592fcfe EB |
1255 | |
1256 | shadow = d_alloc(parent, &dir->d_name); | |
1257 | if (!shadow) | |
1258 | goto nomem; | |
1259 | ||
3e519038 | 1260 | sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR); |
b592fcfe EB |
1261 | if (!sd) |
1262 | goto nomem; | |
3e519038 | 1263 | sd->s_elem.dir.kobj = kobj; |
b592fcfe | 1264 | |
fb6896da TH |
1265 | sysfs_addrm_start(&acxt, parent_sd); |
1266 | ||
1267 | /* add but don't link into children list */ | |
1268 | sysfs_add_one(&acxt, sd); | |
1269 | ||
1270 | /* attach and instantiate dentry */ | |
1271 | sysfs_attach_dentry(sd, shadow); | |
b592fcfe | 1272 | d_instantiate(shadow, igrab(inode)); |
fb6896da TH |
1273 | inc_nlink(inode); /* tj: synchronization? */ |
1274 | ||
1275 | sysfs_addrm_finish(&acxt); | |
b592fcfe EB |
1276 | |
1277 | dget(shadow); /* Extra count - pin the dentry in core */ | |
1278 | ||
51225039 TH |
1279 | goto out_dput; |
1280 | ||
1281 | nomem: | |
b592fcfe | 1282 | dput(shadow); |
608e266a | 1283 | sd = ERR_PTR(-ENOMEM); |
51225039 TH |
1284 | out_dput: |
1285 | dput(dir); | |
1286 | out: | |
1287 | return sd; | |
b592fcfe EB |
1288 | } |
1289 | ||
1290 | /** | |
1291 | * sysfs_remove_shadow_dir - remove an object's directory. | |
608e266a | 1292 | * @shadow_sd: sysfs_dirent of shadow directory |
b592fcfe EB |
1293 | * |
1294 | * The only thing special about this is that we remove any files in | |
1295 | * the directory before we remove the directory, and we've inlined | |
1296 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
1297 | */ | |
1298 | ||
608e266a | 1299 | void sysfs_remove_shadow_dir(struct sysfs_dirent *shadow_sd) |
b592fcfe | 1300 | { |
608e266a | 1301 | __sysfs_remove_dir(shadow_sd); |
b592fcfe EB |
1302 | } |
1303 | ||
4b6f5d20 | 1304 | const struct file_operations sysfs_dir_operations = { |
1da177e4 LT |
1305 | .open = sysfs_dir_open, |
1306 | .release = sysfs_dir_close, | |
1307 | .llseek = sysfs_dir_lseek, | |
1308 | .read = generic_read_dir, | |
1309 | .readdir = sysfs_readdir, | |
1310 | }; |