Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
6d66f5cd TH |
2 | * fs/sysfs/dir.c - sysfs core and dir operation implementation |
3 | * | |
4 | * Copyright (c) 2001-3 Patrick Mochel | |
5 | * Copyright (c) 2007 SUSE Linux Products GmbH | |
6 | * Copyright (c) 2007 Tejun Heo <teheo@suse.de> | |
7 | * | |
8 | * This file is released under the GPLv2. | |
9 | * | |
10 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
1da177e4 LT |
11 | */ |
12 | ||
13 | #undef DEBUG | |
14 | ||
15 | #include <linux/fs.h> | |
16 | #include <linux/mount.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/kobject.h> | |
5f45f1a7 | 19 | #include <linux/namei.h> |
2b611bb7 | 20 | #include <linux/idr.h> |
8619f979 | 21 | #include <linux/completion.h> |
869512ab | 22 | #include <linux/mutex.h> |
c6f87733 | 23 | #include <linux/slab.h> |
1da177e4 LT |
24 | #include "sysfs.h" |
25 | ||
3007e997 | 26 | DEFINE_MUTEX(sysfs_mutex); |
932ea2e3 | 27 | DEFINE_MUTEX(sysfs_rename_mutex); |
f7a75f0a | 28 | DEFINE_SPINLOCK(sysfs_assoc_lock); |
1da177e4 | 29 | |
f7a75f0a | 30 | static DEFINE_SPINLOCK(sysfs_ino_lock); |
2b611bb7 TH |
31 | static DEFINE_IDA(sysfs_ino_ida); |
32 | ||
0c73f18b TH |
33 | /** |
34 | * sysfs_link_sibling - link sysfs_dirent into sibling list | |
35 | * @sd: sysfs_dirent of interest | |
36 | * | |
37 | * Link @sd into its sibling list which starts from | |
bc747f37 | 38 | * sd->s_parent->s_dir.children. |
0c73f18b TH |
39 | * |
40 | * Locking: | |
3007e997 | 41 | * mutex_lock(sysfs_mutex) |
0c73f18b | 42 | */ |
41fc1c27 | 43 | static void sysfs_link_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
44 | { |
45 | struct sysfs_dirent *parent_sd = sd->s_parent; | |
3efa65b9 | 46 | struct sysfs_dirent **pos; |
0c73f18b TH |
47 | |
48 | BUG_ON(sd->s_sibling); | |
3efa65b9 EB |
49 | |
50 | /* Store directory entries in order by ino. This allows | |
51 | * readdir to properly restart without having to add a | |
bc747f37 | 52 | * cursor into the s_dir.children list. |
3efa65b9 | 53 | */ |
bc747f37 | 54 | for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) { |
3efa65b9 EB |
55 | if (sd->s_ino < (*pos)->s_ino) |
56 | break; | |
57 | } | |
58 | sd->s_sibling = *pos; | |
59 | *pos = sd; | |
0c73f18b TH |
60 | } |
61 | ||
62 | /** | |
63 | * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list | |
64 | * @sd: sysfs_dirent of interest | |
65 | * | |
66 | * Unlink @sd from its sibling list which starts from | |
bc747f37 | 67 | * sd->s_parent->s_dir.children. |
0c73f18b TH |
68 | * |
69 | * Locking: | |
3007e997 | 70 | * mutex_lock(sysfs_mutex) |
0c73f18b | 71 | */ |
41fc1c27 | 72 | static void sysfs_unlink_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
73 | { |
74 | struct sysfs_dirent **pos; | |
75 | ||
bc747f37 TH |
76 | for (pos = &sd->s_parent->s_dir.children; *pos; |
77 | pos = &(*pos)->s_sibling) { | |
0c73f18b TH |
78 | if (*pos == sd) { |
79 | *pos = sd->s_sibling; | |
80 | sd->s_sibling = NULL; | |
81 | break; | |
82 | } | |
83 | } | |
84 | } | |
85 | ||
53e0ae92 TH |
86 | /** |
87 | * sysfs_get_dentry - get dentry for the given sysfs_dirent | |
88 | * @sd: sysfs_dirent of interest | |
89 | * | |
90 | * Get dentry for @sd. Dentry is looked up if currently not | |
e0712bbf TH |
91 | * present. This function descends from the root looking up |
92 | * dentry for each step. | |
53e0ae92 TH |
93 | * |
94 | * LOCKING: | |
932ea2e3 | 95 | * mutex_lock(sysfs_rename_mutex) |
53e0ae92 TH |
96 | * |
97 | * RETURNS: | |
98 | * Pointer to found dentry on success, ERR_PTR() value on error. | |
99 | */ | |
100 | struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd) | |
101 | { | |
e0712bbf | 102 | struct dentry *dentry = dget(sysfs_sb->s_root); |
53e0ae92 | 103 | |
e0712bbf TH |
104 | while (dentry->d_fsdata != sd) { |
105 | struct sysfs_dirent *cur; | |
106 | struct dentry *parent; | |
53e0ae92 | 107 | |
e0712bbf TH |
108 | /* find the first ancestor which hasn't been looked up */ |
109 | cur = sd; | |
110 | while (cur->s_parent != dentry->d_fsdata) | |
53e0ae92 TH |
111 | cur = cur->s_parent; |
112 | ||
53e0ae92 | 113 | /* look it up */ |
e0712bbf TH |
114 | parent = dentry; |
115 | mutex_lock(&parent->d_inode->i_mutex); | |
eead1911 | 116 | dentry = lookup_one_noperm(cur->s_name, parent); |
e0712bbf TH |
117 | mutex_unlock(&parent->d_inode->i_mutex); |
118 | dput(parent); | |
53e0ae92 | 119 | |
e0712bbf TH |
120 | if (IS_ERR(dentry)) |
121 | break; | |
53e0ae92 | 122 | } |
53e0ae92 TH |
123 | return dentry; |
124 | } | |
125 | ||
b6b4a439 TH |
126 | /** |
127 | * sysfs_get_active - get an active reference to sysfs_dirent | |
128 | * @sd: sysfs_dirent to get an active reference to | |
129 | * | |
130 | * Get an active reference of @sd. This function is noop if @sd | |
131 | * is NULL. | |
132 | * | |
133 | * RETURNS: | |
134 | * Pointer to @sd on success, NULL on failure. | |
135 | */ | |
78e9d367 | 136 | static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) |
b6b4a439 | 137 | { |
8619f979 TH |
138 | if (unlikely(!sd)) |
139 | return NULL; | |
140 | ||
141 | while (1) { | |
142 | int v, t; | |
143 | ||
144 | v = atomic_read(&sd->s_active); | |
145 | if (unlikely(v < 0)) | |
146 | return NULL; | |
147 | ||
148 | t = atomic_cmpxchg(&sd->s_active, v, v + 1); | |
149 | if (likely(t == v)) | |
150 | return sd; | |
151 | if (t < 0) | |
152 | return NULL; | |
153 | ||
154 | cpu_relax(); | |
b6b4a439 | 155 | } |
b6b4a439 TH |
156 | } |
157 | ||
158 | /** | |
159 | * sysfs_put_active - put an active reference to sysfs_dirent | |
160 | * @sd: sysfs_dirent to put an active reference to | |
161 | * | |
162 | * Put an active reference to @sd. This function is noop if @sd | |
163 | * is NULL. | |
164 | */ | |
78e9d367 | 165 | static void sysfs_put_active(struct sysfs_dirent *sd) |
b6b4a439 | 166 | { |
8619f979 TH |
167 | struct completion *cmpl; |
168 | int v; | |
169 | ||
170 | if (unlikely(!sd)) | |
171 | return; | |
172 | ||
173 | v = atomic_dec_return(&sd->s_active); | |
174 | if (likely(v != SD_DEACTIVATED_BIAS)) | |
175 | return; | |
176 | ||
177 | /* atomic_dec_return() is a mb(), we'll always see the updated | |
0c73f18b | 178 | * sd->s_sibling. |
8619f979 | 179 | */ |
0c73f18b | 180 | cmpl = (void *)sd->s_sibling; |
8619f979 | 181 | complete(cmpl); |
b6b4a439 TH |
182 | } |
183 | ||
184 | /** | |
185 | * sysfs_get_active_two - get active references to sysfs_dirent and parent | |
186 | * @sd: sysfs_dirent of interest | |
187 | * | |
188 | * Get active reference to @sd and its parent. Parent's active | |
189 | * reference is grabbed first. This function is noop if @sd is | |
190 | * NULL. | |
191 | * | |
192 | * RETURNS: | |
193 | * Pointer to @sd on success, NULL on failure. | |
194 | */ | |
195 | struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) | |
196 | { | |
197 | if (sd) { | |
198 | if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) | |
199 | return NULL; | |
200 | if (unlikely(!sysfs_get_active(sd))) { | |
201 | sysfs_put_active(sd->s_parent); | |
202 | return NULL; | |
203 | } | |
204 | } | |
205 | return sd; | |
206 | } | |
207 | ||
208 | /** | |
209 | * sysfs_put_active_two - put active references to sysfs_dirent and parent | |
210 | * @sd: sysfs_dirent of interest | |
211 | * | |
212 | * Put active references to @sd and its parent. This function is | |
213 | * noop if @sd is NULL. | |
214 | */ | |
215 | void sysfs_put_active_two(struct sysfs_dirent *sd) | |
216 | { | |
217 | if (sd) { | |
218 | sysfs_put_active(sd); | |
219 | sysfs_put_active(sd->s_parent); | |
220 | } | |
221 | } | |
222 | ||
223 | /** | |
224 | * sysfs_deactivate - deactivate sysfs_dirent | |
225 | * @sd: sysfs_dirent to deactivate | |
226 | * | |
8619f979 | 227 | * Deny new active references and drain existing ones. |
b6b4a439 | 228 | */ |
fb6896da | 229 | static void sysfs_deactivate(struct sysfs_dirent *sd) |
b6b4a439 | 230 | { |
8619f979 TH |
231 | DECLARE_COMPLETION_ONSTACK(wait); |
232 | int v; | |
b6b4a439 | 233 | |
380e6fbb | 234 | BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
0c73f18b | 235 | sd->s_sibling = (void *)&wait; |
8619f979 TH |
236 | |
237 | /* atomic_add_return() is a mb(), put_active() will always see | |
0c73f18b | 238 | * the updated sd->s_sibling. |
b6b4a439 | 239 | */ |
8619f979 TH |
240 | v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
241 | ||
242 | if (v != SD_DEACTIVATED_BIAS) | |
243 | wait_for_completion(&wait); | |
244 | ||
0c73f18b | 245 | sd->s_sibling = NULL; |
b6b4a439 TH |
246 | } |
247 | ||
42b37df6 | 248 | static int sysfs_alloc_ino(ino_t *pino) |
2b611bb7 TH |
249 | { |
250 | int ino, rc; | |
251 | ||
252 | retry: | |
253 | spin_lock(&sysfs_ino_lock); | |
254 | rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); | |
255 | spin_unlock(&sysfs_ino_lock); | |
256 | ||
257 | if (rc == -EAGAIN) { | |
258 | if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) | |
259 | goto retry; | |
260 | rc = -ENOMEM; | |
261 | } | |
262 | ||
263 | *pino = ino; | |
264 | return rc; | |
265 | } | |
266 | ||
267 | static void sysfs_free_ino(ino_t ino) | |
268 | { | |
269 | spin_lock(&sysfs_ino_lock); | |
270 | ida_remove(&sysfs_ino_ida, ino); | |
271 | spin_unlock(&sysfs_ino_lock); | |
272 | } | |
273 | ||
fa7f912a TH |
274 | void release_sysfs_dirent(struct sysfs_dirent * sd) |
275 | { | |
13b3086d TH |
276 | struct sysfs_dirent *parent_sd; |
277 | ||
278 | repeat: | |
3007e997 TH |
279 | /* Moving/renaming is always done while holding reference. |
280 | * sd->s_parent won't change beneath us. | |
281 | */ | |
13b3086d TH |
282 | parent_sd = sd->s_parent; |
283 | ||
b402d72c | 284 | if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
b1fc3d61 | 285 | sysfs_put(sd->s_symlink.target_sd); |
b402d72c | 286 | if (sysfs_type(sd) & SYSFS_COPY_NAME) |
0c096b50 | 287 | kfree(sd->s_name); |
fa7f912a | 288 | kfree(sd->s_iattr); |
2b611bb7 | 289 | sysfs_free_ino(sd->s_ino); |
fa7f912a | 290 | kmem_cache_free(sysfs_dir_cachep, sd); |
13b3086d TH |
291 | |
292 | sd = parent_sd; | |
293 | if (sd && atomic_dec_and_test(&sd->s_count)) | |
294 | goto repeat; | |
fa7f912a TH |
295 | } |
296 | ||
1da177e4 LT |
297 | static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) |
298 | { | |
299 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
300 | ||
5a26b79c | 301 | sysfs_put(sd); |
1da177e4 LT |
302 | iput(inode); |
303 | } | |
304 | ||
305 | static struct dentry_operations sysfs_dentry_ops = { | |
306 | .d_iput = sysfs_d_iput, | |
307 | }; | |
308 | ||
3e519038 | 309 | struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
1da177e4 | 310 | { |
0c096b50 | 311 | char *dup_name = NULL; |
01da2425 | 312 | struct sysfs_dirent *sd; |
0c096b50 TH |
313 | |
314 | if (type & SYSFS_COPY_NAME) { | |
315 | name = dup_name = kstrdup(name, GFP_KERNEL); | |
316 | if (!name) | |
01da2425 | 317 | return NULL; |
0c096b50 | 318 | } |
1da177e4 | 319 | |
c3762229 | 320 | sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
1da177e4 | 321 | if (!sd) |
01da2425 | 322 | goto err_out1; |
1da177e4 | 323 | |
0c096b50 | 324 | if (sysfs_alloc_ino(&sd->s_ino)) |
01da2425 | 325 | goto err_out2; |
2b611bb7 | 326 | |
1da177e4 | 327 | atomic_set(&sd->s_count, 1); |
8619f979 | 328 | atomic_set(&sd->s_active, 0); |
a26cd722 | 329 | |
0c096b50 | 330 | sd->s_name = name; |
a26cd722 | 331 | sd->s_mode = mode; |
b402d72c | 332 | sd->s_flags = type; |
1da177e4 LT |
333 | |
334 | return sd; | |
0c096b50 | 335 | |
01da2425 | 336 | err_out2: |
0c096b50 | 337 | kmem_cache_free(sysfs_dir_cachep, sd); |
01da2425 AM |
338 | err_out1: |
339 | kfree(dup_name); | |
0c096b50 | 340 | return NULL; |
1da177e4 LT |
341 | } |
342 | ||
fb6896da TH |
343 | static int sysfs_ilookup_test(struct inode *inode, void *arg) |
344 | { | |
345 | struct sysfs_dirent *sd = arg; | |
346 | return inode->i_ino == sd->s_ino; | |
347 | } | |
348 | ||
3007e997 | 349 | /** |
fb6896da TH |
350 | * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
351 | * @acxt: pointer to sysfs_addrm_cxt to be used | |
352 | * @parent_sd: parent sysfs_dirent | |
3007e997 | 353 | * |
fb6896da TH |
354 | * This function is called when the caller is about to add or |
355 | * remove sysfs_dirent under @parent_sd. This function acquires | |
356 | * sysfs_mutex, grabs inode for @parent_sd if available and lock | |
357 | * i_mutex of it. @acxt is used to keep and pass context to | |
358 | * other addrm functions. | |
3007e997 TH |
359 | * |
360 | * LOCKING: | |
fb6896da TH |
361 | * Kernel thread context (may sleep). sysfs_mutex is locked on |
362 | * return. i_mutex of parent inode is locked on return if | |
363 | * available. | |
3007e997 | 364 | */ |
fb6896da TH |
365 | void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
366 | struct sysfs_dirent *parent_sd) | |
b592fcfe | 367 | { |
fb6896da | 368 | struct inode *inode; |
b592fcfe | 369 | |
fb6896da TH |
370 | memset(acxt, 0, sizeof(*acxt)); |
371 | acxt->parent_sd = parent_sd; | |
372 | ||
373 | /* Lookup parent inode. inode initialization and I_NEW | |
374 | * clearing are protected by sysfs_mutex. By grabbing it and | |
375 | * looking up with _nowait variant, inode state can be | |
376 | * determined reliably. | |
377 | */ | |
378 | mutex_lock(&sysfs_mutex); | |
379 | ||
380 | inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test, | |
381 | parent_sd); | |
382 | ||
383 | if (inode && !(inode->i_state & I_NEW)) { | |
384 | /* parent inode available */ | |
385 | acxt->parent_inode = inode; | |
386 | ||
387 | /* sysfs_mutex is below i_mutex in lock hierarchy. | |
388 | * First, trylock i_mutex. If fails, unlock | |
389 | * sysfs_mutex and lock them in order. | |
390 | */ | |
391 | if (!mutex_trylock(&inode->i_mutex)) { | |
392 | mutex_unlock(&sysfs_mutex); | |
393 | mutex_lock(&inode->i_mutex); | |
394 | mutex_lock(&sysfs_mutex); | |
395 | } | |
396 | } else | |
397 | iput(inode); | |
398 | } | |
399 | ||
400 | /** | |
36ce6dad | 401 | * __sysfs_add_one - add sysfs_dirent to parent without warning |
fb6896da TH |
402 | * @acxt: addrm context to use |
403 | * @sd: sysfs_dirent to be added | |
404 | * | |
405 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
181b2e4b TH |
406 | * nlink of parent inode if @sd is a directory and link into the |
407 | * children list of the parent. | |
fb6896da TH |
408 | * |
409 | * This function should be called between calls to | |
410 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
411 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
412 | * | |
413 | * LOCKING: | |
414 | * Determined by sysfs_addrm_start(). | |
23dc2799 TH |
415 | * |
416 | * RETURNS: | |
417 | * 0 on success, -EEXIST if entry with the given name already | |
418 | * exists. | |
fb6896da | 419 | */ |
36ce6dad | 420 | int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
fb6896da | 421 | { |
0599ad53 | 422 | if (sysfs_find_dirent(acxt->parent_sd, sd->s_name)) |
23dc2799 TH |
423 | return -EEXIST; |
424 | ||
fb6896da TH |
425 | sd->s_parent = sysfs_get(acxt->parent_sd); |
426 | ||
427 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
428 | inc_nlink(acxt->parent_inode); | |
429 | ||
430 | acxt->cnt++; | |
41fc1c27 TH |
431 | |
432 | sysfs_link_sibling(sd); | |
23dc2799 TH |
433 | |
434 | return 0; | |
fb6896da TH |
435 | } |
436 | ||
36ce6dad CH |
437 | /** |
438 | * sysfs_add_one - add sysfs_dirent to parent | |
439 | * @acxt: addrm context to use | |
440 | * @sd: sysfs_dirent to be added | |
441 | * | |
442 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
443 | * nlink of parent inode if @sd is a directory and link into the | |
444 | * children list of the parent. | |
445 | * | |
446 | * This function should be called between calls to | |
447 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
448 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
449 | * | |
450 | * LOCKING: | |
451 | * Determined by sysfs_addrm_start(). | |
452 | * | |
453 | * RETURNS: | |
454 | * 0 on success, -EEXIST if entry with the given name already | |
455 | * exists. | |
456 | */ | |
457 | int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
458 | { | |
459 | int ret; | |
460 | ||
461 | ret = __sysfs_add_one(acxt, sd); | |
462 | if (ret == -EEXIST) { | |
463 | printk(KERN_WARNING "sysfs: duplicate filename '%s' " | |
464 | "can not be created\n", sd->s_name); | |
465 | WARN_ON(1); | |
466 | } | |
467 | return ret; | |
468 | } | |
469 | ||
fb6896da TH |
470 | /** |
471 | * sysfs_remove_one - remove sysfs_dirent from parent | |
472 | * @acxt: addrm context to use | |
9fd5b1c9 | 473 | * @sd: sysfs_dirent to be removed |
fb6896da TH |
474 | * |
475 | * Mark @sd removed and drop nlink of parent inode if @sd is a | |
181b2e4b | 476 | * directory. @sd is unlinked from the children list. |
fb6896da TH |
477 | * |
478 | * This function should be called between calls to | |
479 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
480 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
481 | * | |
482 | * LOCKING: | |
483 | * Determined by sysfs_addrm_start(). | |
484 | */ | |
485 | void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
486 | { | |
41fc1c27 TH |
487 | BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED); |
488 | ||
489 | sysfs_unlink_sibling(sd); | |
fb6896da TH |
490 | |
491 | sd->s_flags |= SYSFS_FLAG_REMOVED; | |
492 | sd->s_sibling = acxt->removed; | |
493 | acxt->removed = sd; | |
494 | ||
495 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
496 | drop_nlink(acxt->parent_inode); | |
497 | ||
498 | acxt->cnt++; | |
499 | } | |
500 | ||
a0edd7c8 TH |
501 | /** |
502 | * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent | |
503 | * @sd: target sysfs_dirent | |
504 | * | |
505 | * Drop dentry for @sd. @sd must have been unlinked from its | |
506 | * parent on entry to this function such that it can't be looked | |
507 | * up anymore. | |
a0edd7c8 TH |
508 | */ |
509 | static void sysfs_drop_dentry(struct sysfs_dirent *sd) | |
510 | { | |
a0edd7c8 | 511 | struct inode *inode; |
89bec097 EB |
512 | struct dentry *dentry; |
513 | ||
514 | inode = ilookup(sysfs_sb, sd->s_ino); | |
515 | if (!inode) | |
516 | return; | |
a0edd7c8 | 517 | |
89bec097 EB |
518 | /* Drop any existing dentries associated with sd. |
519 | * | |
520 | * For the dentry to be properly freed we need to grab a | |
521 | * reference to the dentry under the dcache lock, unhash it, | |
522 | * and then put it. The playing with the dentry count allows | |
523 | * dput to immediately free the dentry if it is not in use. | |
a0edd7c8 | 524 | */ |
89bec097 | 525 | repeat: |
a0edd7c8 | 526 | spin_lock(&dcache_lock); |
89bec097 EB |
527 | list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
528 | if (d_unhashed(dentry)) | |
529 | continue; | |
530 | dget_locked(dentry); | |
a0edd7c8 TH |
531 | spin_lock(&dentry->d_lock); |
532 | __d_drop(dentry); | |
533 | spin_unlock(&dentry->d_lock); | |
89bec097 EB |
534 | spin_unlock(&dcache_lock); |
535 | dput(dentry); | |
536 | goto repeat; | |
a0edd7c8 | 537 | } |
a0edd7c8 | 538 | spin_unlock(&dcache_lock); |
a0edd7c8 TH |
539 | |
540 | /* adjust nlink and update timestamp */ | |
89bec097 | 541 | mutex_lock(&inode->i_mutex); |
a0edd7c8 | 542 | |
89bec097 EB |
543 | inode->i_ctime = CURRENT_TIME; |
544 | drop_nlink(inode); | |
545 | if (sysfs_type(sd) == SYSFS_DIR) | |
a0edd7c8 | 546 | drop_nlink(inode); |
a0edd7c8 | 547 | |
89bec097 EB |
548 | mutex_unlock(&inode->i_mutex); |
549 | ||
550 | iput(inode); | |
a0edd7c8 TH |
551 | } |
552 | ||
fb6896da TH |
553 | /** |
554 | * sysfs_addrm_finish - finish up sysfs_dirent add/remove | |
555 | * @acxt: addrm context to finish up | |
556 | * | |
557 | * Finish up sysfs_dirent add/remove. Resources acquired by | |
558 | * sysfs_addrm_start() are released and removed sysfs_dirents are | |
559 | * cleaned up. Timestamps on the parent inode are updated. | |
560 | * | |
561 | * LOCKING: | |
562 | * All mutexes acquired by sysfs_addrm_start() are released. | |
fb6896da | 563 | */ |
990e53f8 | 564 | void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) |
fb6896da TH |
565 | { |
566 | /* release resources acquired by sysfs_addrm_start() */ | |
567 | mutex_unlock(&sysfs_mutex); | |
568 | if (acxt->parent_inode) { | |
569 | struct inode *inode = acxt->parent_inode; | |
570 | ||
571 | /* if added/removed, update timestamps on the parent */ | |
572 | if (acxt->cnt) | |
573 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
574 | ||
575 | mutex_unlock(&inode->i_mutex); | |
576 | iput(inode); | |
577 | } | |
578 | ||
579 | /* kill removed sysfs_dirents */ | |
580 | while (acxt->removed) { | |
581 | struct sysfs_dirent *sd = acxt->removed; | |
582 | ||
583 | acxt->removed = sd->s_sibling; | |
584 | sd->s_sibling = NULL; | |
585 | ||
586 | sysfs_drop_dentry(sd); | |
587 | sysfs_deactivate(sd); | |
588 | sysfs_put(sd); | |
13b3086d | 589 | } |
b592fcfe EB |
590 | } |
591 | ||
f0b0af47 TH |
592 | /** |
593 | * sysfs_find_dirent - find sysfs_dirent with the given name | |
594 | * @parent_sd: sysfs_dirent to search under | |
595 | * @name: name to look for | |
596 | * | |
597 | * Look for sysfs_dirent with name @name under @parent_sd. | |
c516865c | 598 | * |
f0b0af47 | 599 | * LOCKING: |
3007e997 | 600 | * mutex_lock(sysfs_mutex) |
c516865c | 601 | * |
f0b0af47 TH |
602 | * RETURNS: |
603 | * Pointer to sysfs_dirent if found, NULL if not. | |
c516865c | 604 | */ |
f0b0af47 TH |
605 | struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, |
606 | const unsigned char *name) | |
c516865c | 607 | { |
f0b0af47 TH |
608 | struct sysfs_dirent *sd; |
609 | ||
bc747f37 | 610 | for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) |
3efa65b9 | 611 | if (!strcmp(sd->s_name, name)) |
f0b0af47 TH |
612 | return sd; |
613 | return NULL; | |
614 | } | |
c516865c | 615 | |
f0b0af47 TH |
616 | /** |
617 | * sysfs_get_dirent - find and get sysfs_dirent with the given name | |
618 | * @parent_sd: sysfs_dirent to search under | |
619 | * @name: name to look for | |
620 | * | |
621 | * Look for sysfs_dirent with name @name under @parent_sd and get | |
622 | * it if found. | |
623 | * | |
624 | * LOCKING: | |
3007e997 | 625 | * Kernel thread context (may sleep). Grabs sysfs_mutex. |
f0b0af47 TH |
626 | * |
627 | * RETURNS: | |
628 | * Pointer to sysfs_dirent if found, NULL if not. | |
629 | */ | |
630 | struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, | |
631 | const unsigned char *name) | |
632 | { | |
633 | struct sysfs_dirent *sd; | |
634 | ||
3007e997 | 635 | mutex_lock(&sysfs_mutex); |
f0b0af47 TH |
636 | sd = sysfs_find_dirent(parent_sd, name); |
637 | sysfs_get(sd); | |
3007e997 | 638 | mutex_unlock(&sysfs_mutex); |
f0b0af47 TH |
639 | |
640 | return sd; | |
c516865c MS |
641 | } |
642 | ||
608e266a TH |
643 | static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
644 | const char *name, struct sysfs_dirent **p_sd) | |
1da177e4 | 645 | { |
1da177e4 | 646 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
51225039 | 647 | struct sysfs_addrm_cxt acxt; |
dfeb9fb0 | 648 | struct sysfs_dirent *sd; |
23dc2799 | 649 | int rc; |
1da177e4 | 650 | |
fc9f54b9 | 651 | /* allocate */ |
3e519038 | 652 | sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
a26cd722 | 653 | if (!sd) |
51225039 | 654 | return -ENOMEM; |
b1fc3d61 | 655 | sd->s_dir.kobj = kobj; |
dfeb9fb0 | 656 | |
fc9f54b9 | 657 | /* link in */ |
51225039 | 658 | sysfs_addrm_start(&acxt, parent_sd); |
23dc2799 TH |
659 | rc = sysfs_add_one(&acxt, sd); |
660 | sysfs_addrm_finish(&acxt); | |
967e35dc | 661 | |
23dc2799 TH |
662 | if (rc == 0) |
663 | *p_sd = sd; | |
664 | else | |
967e35dc | 665 | sysfs_put(sd); |
dfeb9fb0 | 666 | |
23dc2799 | 667 | return rc; |
1da177e4 LT |
668 | } |
669 | ||
608e266a TH |
670 | int sysfs_create_subdir(struct kobject *kobj, const char *name, |
671 | struct sysfs_dirent **p_sd) | |
1da177e4 | 672 | { |
608e266a | 673 | return create_dir(kobj, kobj->sd, name, p_sd); |
1da177e4 LT |
674 | } |
675 | ||
676 | /** | |
677 | * sysfs_create_dir - create a directory for an object. | |
1da177e4 LT |
678 | * @kobj: object we're creating directory for. |
679 | */ | |
90bc6135 | 680 | int sysfs_create_dir(struct kobject * kobj) |
1da177e4 | 681 | { |
608e266a | 682 | struct sysfs_dirent *parent_sd, *sd; |
1da177e4 LT |
683 | int error = 0; |
684 | ||
685 | BUG_ON(!kobj); | |
686 | ||
90bc6135 | 687 | if (kobj->parent) |
608e266a | 688 | parent_sd = kobj->parent->sd; |
1da177e4 | 689 | else |
7d0c7d67 | 690 | parent_sd = &sysfs_root; |
1da177e4 | 691 | |
608e266a | 692 | error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd); |
1da177e4 | 693 | if (!error) |
608e266a | 694 | kobj->sd = sd; |
1da177e4 LT |
695 | return error; |
696 | } | |
697 | ||
1da177e4 LT |
698 | static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
699 | struct nameidata *nd) | |
700 | { | |
6cb52147 | 701 | struct dentry *ret = NULL; |
a7a04754 TH |
702 | struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata; |
703 | struct sysfs_dirent *sd; | |
fc9f54b9 | 704 | struct inode *inode; |
1da177e4 | 705 | |
6cb52147 TH |
706 | mutex_lock(&sysfs_mutex); |
707 | ||
94777e09 | 708 | sd = sysfs_find_dirent(parent_sd, dentry->d_name.name); |
1da177e4 | 709 | |
fc9f54b9 | 710 | /* no such entry */ |
e49452c6 TH |
711 | if (!sd) { |
712 | ret = ERR_PTR(-ENOENT); | |
6cb52147 | 713 | goto out_unlock; |
e49452c6 | 714 | } |
fc9f54b9 TH |
715 | |
716 | /* attach dentry and inode */ | |
8312a8d7 | 717 | inode = sysfs_get_inode(sd); |
6cb52147 TH |
718 | if (!inode) { |
719 | ret = ERR_PTR(-ENOMEM); | |
720 | goto out_unlock; | |
721 | } | |
3007e997 | 722 | |
d6b4fd2f TH |
723 | /* instantiate and hash dentry */ |
724 | dentry->d_op = &sysfs_dentry_ops; | |
725 | dentry->d_fsdata = sysfs_get(sd); | |
119dd52b | 726 | d_instantiate(dentry, inode); |
d6b4fd2f | 727 | d_rehash(dentry); |
fc9f54b9 | 728 | |
6cb52147 | 729 | out_unlock: |
3007e997 | 730 | mutex_unlock(&sysfs_mutex); |
6cb52147 | 731 | return ret; |
1da177e4 LT |
732 | } |
733 | ||
c5ef1c42 | 734 | const struct inode_operations sysfs_dir_inode_operations = { |
1da177e4 | 735 | .lookup = sysfs_lookup, |
988d186d | 736 | .setattr = sysfs_setattr, |
1da177e4 LT |
737 | }; |
738 | ||
608e266a | 739 | static void remove_dir(struct sysfs_dirent *sd) |
1da177e4 | 740 | { |
fb6896da | 741 | struct sysfs_addrm_cxt acxt; |
1da177e4 | 742 | |
fb6896da | 743 | sysfs_addrm_start(&acxt, sd->s_parent); |
fb6896da TH |
744 | sysfs_remove_one(&acxt, sd); |
745 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
746 | } |
747 | ||
608e266a | 748 | void sysfs_remove_subdir(struct sysfs_dirent *sd) |
1da177e4 | 749 | { |
608e266a | 750 | remove_dir(sd); |
1da177e4 LT |
751 | } |
752 | ||
753 | ||
608e266a | 754 | static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
1da177e4 | 755 | { |
fb6896da | 756 | struct sysfs_addrm_cxt acxt; |
0c73f18b | 757 | struct sysfs_dirent **pos; |
1da177e4 | 758 | |
608e266a | 759 | if (!dir_sd) |
1da177e4 LT |
760 | return; |
761 | ||
608e266a | 762 | pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
fb6896da | 763 | sysfs_addrm_start(&acxt, dir_sd); |
bc747f37 | 764 | pos = &dir_sd->s_dir.children; |
0c73f18b TH |
765 | while (*pos) { |
766 | struct sysfs_dirent *sd = *pos; | |
767 | ||
3efa65b9 | 768 | if (sysfs_type(sd) != SYSFS_DIR) |
fb6896da | 769 | sysfs_remove_one(&acxt, sd); |
41fc1c27 | 770 | else |
0c73f18b | 771 | pos = &(*pos)->s_sibling; |
1da177e4 | 772 | } |
fb6896da | 773 | sysfs_addrm_finish(&acxt); |
0ab66088 | 774 | |
608e266a | 775 | remove_dir(dir_sd); |
b592fcfe EB |
776 | } |
777 | ||
778 | /** | |
779 | * sysfs_remove_dir - remove an object's directory. | |
780 | * @kobj: object. | |
781 | * | |
782 | * The only thing special about this is that we remove any files in | |
783 | * the directory before we remove the directory, and we've inlined | |
784 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
785 | */ | |
786 | ||
787 | void sysfs_remove_dir(struct kobject * kobj) | |
788 | { | |
608e266a | 789 | struct sysfs_dirent *sd = kobj->sd; |
aecdceda | 790 | |
5f995323 | 791 | spin_lock(&sysfs_assoc_lock); |
608e266a | 792 | kobj->sd = NULL; |
5f995323 | 793 | spin_unlock(&sysfs_assoc_lock); |
aecdceda | 794 | |
608e266a | 795 | __sysfs_remove_dir(sd); |
1da177e4 LT |
796 | } |
797 | ||
90bc6135 | 798 | int sysfs_rename_dir(struct kobject * kobj, const char *new_name) |
1da177e4 | 799 | { |
9918f9a4 | 800 | struct sysfs_dirent *sd = kobj->sd; |
90bc6135 | 801 | struct dentry *parent = NULL; |
51225039 TH |
802 | struct dentry *old_dentry = NULL, *new_dentry = NULL; |
803 | const char *dup_name = NULL; | |
996b7376 | 804 | int error; |
1da177e4 | 805 | |
932ea2e3 EB |
806 | mutex_lock(&sysfs_rename_mutex); |
807 | ||
9918f9a4 EB |
808 | error = 0; |
809 | if (strcmp(sd->s_name, new_name) == 0) | |
810 | goto out; /* nothing to rename */ | |
811 | ||
ff869de7 | 812 | /* get the original dentry */ |
51225039 TH |
813 | old_dentry = sysfs_get_dentry(sd); |
814 | if (IS_ERR(old_dentry)) { | |
815 | error = PTR_ERR(old_dentry); | |
456ef155 | 816 | old_dentry = NULL; |
9918f9a4 | 817 | goto out; |
51225039 TH |
818 | } |
819 | ||
ff869de7 | 820 | parent = old_dentry->d_parent; |
1da177e4 | 821 | |
90bc6135 EB |
822 | /* lock parent and get dentry for new name */ |
823 | mutex_lock(&parent->d_inode->i_mutex); | |
9918f9a4 | 824 | mutex_lock(&sysfs_mutex); |
1da177e4 | 825 | |
9918f9a4 EB |
826 | error = -EEXIST; |
827 | if (sysfs_find_dirent(sd->s_parent, new_name)) | |
51225039 | 828 | goto out_unlock; |
996b7376 | 829 | |
9918f9a4 EB |
830 | error = -ENOMEM; |
831 | new_dentry = d_alloc_name(parent, new_name); | |
832 | if (!new_dentry) | |
51225039 | 833 | goto out_unlock; |
996b7376 | 834 | |
0c096b50 TH |
835 | /* rename kobject and sysfs_dirent */ |
836 | error = -ENOMEM; | |
837 | new_name = dup_name = kstrdup(new_name, GFP_KERNEL); | |
838 | if (!new_name) | |
9918f9a4 | 839 | goto out_unlock; |
0c096b50 | 840 | |
996b7376 TH |
841 | error = kobject_set_name(kobj, "%s", new_name); |
842 | if (error) | |
9918f9a4 | 843 | goto out_unlock; |
996b7376 | 844 | |
51225039 | 845 | dup_name = sd->s_name; |
0c096b50 TH |
846 | sd->s_name = new_name; |
847 | ||
ff869de7 | 848 | /* rename */ |
996b7376 | 849 | d_add(new_dentry, NULL); |
5a26b79c | 850 | d_move(old_dentry, new_dentry); |
996b7376 | 851 | |
996b7376 | 852 | error = 0; |
996b7376 | 853 | out_unlock: |
9918f9a4 | 854 | mutex_unlock(&sysfs_mutex); |
90bc6135 | 855 | mutex_unlock(&parent->d_inode->i_mutex); |
51225039 | 856 | kfree(dup_name); |
51225039 TH |
857 | dput(old_dentry); |
858 | dput(new_dentry); | |
9918f9a4 | 859 | out: |
932ea2e3 | 860 | mutex_unlock(&sysfs_rename_mutex); |
1da177e4 LT |
861 | return error; |
862 | } | |
863 | ||
51225039 | 864 | int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) |
8a82472f | 865 | { |
51225039 TH |
866 | struct sysfs_dirent *sd = kobj->sd; |
867 | struct sysfs_dirent *new_parent_sd; | |
868 | struct dentry *old_parent, *new_parent = NULL; | |
869 | struct dentry *old_dentry = NULL, *new_dentry = NULL; | |
8a82472f CH |
870 | int error; |
871 | ||
932ea2e3 | 872 | mutex_lock(&sysfs_rename_mutex); |
51225039 TH |
873 | BUG_ON(!sd->s_parent); |
874 | new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root; | |
875 | ||
45aaae9c EB |
876 | error = 0; |
877 | if (sd->s_parent == new_parent_sd) | |
878 | goto out; /* nothing to move */ | |
879 | ||
51225039 TH |
880 | /* get dentries */ |
881 | old_dentry = sysfs_get_dentry(sd); | |
882 | if (IS_ERR(old_dentry)) { | |
883 | error = PTR_ERR(old_dentry); | |
456ef155 | 884 | old_dentry = NULL; |
45aaae9c | 885 | goto out; |
51225039 | 886 | } |
5a26b79c | 887 | old_parent = old_dentry->d_parent; |
51225039 TH |
888 | |
889 | new_parent = sysfs_get_dentry(new_parent_sd); | |
890 | if (IS_ERR(new_parent)) { | |
891 | error = PTR_ERR(new_parent); | |
456ef155 | 892 | new_parent = NULL; |
45aaae9c | 893 | goto out; |
51225039 | 894 | } |
8a82472f CH |
895 | |
896 | again: | |
51225039 TH |
897 | mutex_lock(&old_parent->d_inode->i_mutex); |
898 | if (!mutex_trylock(&new_parent->d_inode->i_mutex)) { | |
899 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
8a82472f CH |
900 | goto again; |
901 | } | |
45aaae9c | 902 | mutex_lock(&sysfs_mutex); |
8a82472f | 903 | |
45aaae9c EB |
904 | error = -EEXIST; |
905 | if (sysfs_find_dirent(new_parent_sd, sd->s_name)) | |
51225039 | 906 | goto out_unlock; |
45aaae9c EB |
907 | |
908 | error = -ENOMEM; | |
909 | new_dentry = d_alloc_name(new_parent, sd->s_name); | |
910 | if (!new_dentry) | |
911 | goto out_unlock; | |
912 | ||
913 | error = 0; | |
8a82472f | 914 | d_add(new_dentry, NULL); |
5a26b79c | 915 | d_move(old_dentry, new_dentry); |
8a82472f CH |
916 | |
917 | /* Remove from old parent's list and insert into new parent's list. */ | |
0c73f18b | 918 | sysfs_unlink_sibling(sd); |
7f7cfffe TH |
919 | sysfs_get(new_parent_sd); |
920 | sysfs_put(sd->s_parent); | |
921 | sd->s_parent = new_parent_sd; | |
0c73f18b | 922 | sysfs_link_sibling(sd); |
8a82472f | 923 | |
51225039 | 924 | out_unlock: |
45aaae9c | 925 | mutex_unlock(&sysfs_mutex); |
51225039 TH |
926 | mutex_unlock(&new_parent->d_inode->i_mutex); |
927 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
45aaae9c | 928 | out: |
51225039 TH |
929 | dput(new_parent); |
930 | dput(old_dentry); | |
931 | dput(new_dentry); | |
932ea2e3 | 932 | mutex_unlock(&sysfs_rename_mutex); |
8a82472f CH |
933 | return error; |
934 | } | |
935 | ||
1da177e4 LT |
936 | /* Relationship between s_mode and the DT_xxx types */ |
937 | static inline unsigned char dt_type(struct sysfs_dirent *sd) | |
938 | { | |
939 | return (sd->s_mode >> 12) & 15; | |
940 | } | |
941 | ||
942 | static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
943 | { | |
f427f5d5 | 944 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 945 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
3efa65b9 | 946 | struct sysfs_dirent *pos; |
1da177e4 | 947 | ino_t ino; |
1da177e4 | 948 | |
3efa65b9 EB |
949 | if (filp->f_pos == 0) { |
950 | ino = parent_sd->s_ino; | |
951 | if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 952 | filp->f_pos++; |
3efa65b9 EB |
953 | } |
954 | if (filp->f_pos == 1) { | |
955 | if (parent_sd->s_parent) | |
956 | ino = parent_sd->s_parent->s_ino; | |
957 | else | |
958 | ino = parent_sd->s_ino; | |
959 | if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 960 | filp->f_pos++; |
3efa65b9 EB |
961 | } |
962 | if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) { | |
963 | mutex_lock(&sysfs_mutex); | |
0c73f18b | 964 | |
3efa65b9 | 965 | /* Skip the dentries we have already reported */ |
bc747f37 | 966 | pos = parent_sd->s_dir.children; |
3efa65b9 EB |
967 | while (pos && (filp->f_pos > pos->s_ino)) |
968 | pos = pos->s_sibling; | |
3007e997 | 969 | |
3efa65b9 EB |
970 | for ( ; pos; pos = pos->s_sibling) { |
971 | const char * name; | |
972 | int len; | |
1da177e4 | 973 | |
3efa65b9 EB |
974 | name = pos->s_name; |
975 | len = strlen(name); | |
976 | filp->f_pos = ino = pos->s_ino; | |
1da177e4 | 977 | |
3efa65b9 EB |
978 | if (filldir(dirent, name, len, filp->f_pos, ino, |
979 | dt_type(pos)) < 0) | |
1da177e4 | 980 | break; |
1da177e4 | 981 | } |
3efa65b9 EB |
982 | if (!pos) |
983 | filp->f_pos = INT_MAX; | |
3007e997 | 984 | mutex_unlock(&sysfs_mutex); |
1da177e4 | 985 | } |
3efa65b9 | 986 | return 0; |
1da177e4 LT |
987 | } |
988 | ||
3efa65b9 | 989 | |
4b6f5d20 | 990 | const struct file_operations sysfs_dir_operations = { |
1da177e4 LT |
991 | .read = generic_read_dir, |
992 | .readdir = sysfs_readdir, | |
993 | }; |