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> |
1da177e4 LT |
23 | #include "sysfs.h" |
24 | ||
3007e997 | 25 | DEFINE_MUTEX(sysfs_mutex); |
932ea2e3 | 26 | DEFINE_MUTEX(sysfs_rename_mutex); |
f7a75f0a | 27 | DEFINE_SPINLOCK(sysfs_assoc_lock); |
1da177e4 | 28 | |
f7a75f0a | 29 | static DEFINE_SPINLOCK(sysfs_ino_lock); |
2b611bb7 TH |
30 | static DEFINE_IDA(sysfs_ino_ida); |
31 | ||
0c73f18b TH |
32 | /** |
33 | * sysfs_link_sibling - link sysfs_dirent into sibling list | |
34 | * @sd: sysfs_dirent of interest | |
35 | * | |
36 | * Link @sd into its sibling list which starts from | |
bc747f37 | 37 | * sd->s_parent->s_dir.children. |
0c73f18b TH |
38 | * |
39 | * Locking: | |
3007e997 | 40 | * mutex_lock(sysfs_mutex) |
0c73f18b | 41 | */ |
41fc1c27 | 42 | static void sysfs_link_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
43 | { |
44 | struct sysfs_dirent *parent_sd = sd->s_parent; | |
3efa65b9 | 45 | struct sysfs_dirent **pos; |
0c73f18b TH |
46 | |
47 | BUG_ON(sd->s_sibling); | |
3efa65b9 EB |
48 | |
49 | /* Store directory entries in order by ino. This allows | |
50 | * readdir to properly restart without having to add a | |
bc747f37 | 51 | * cursor into the s_dir.children list. |
3efa65b9 | 52 | */ |
bc747f37 | 53 | for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) { |
3efa65b9 EB |
54 | if (sd->s_ino < (*pos)->s_ino) |
55 | break; | |
56 | } | |
57 | sd->s_sibling = *pos; | |
58 | *pos = sd; | |
0c73f18b TH |
59 | } |
60 | ||
61 | /** | |
62 | * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list | |
63 | * @sd: sysfs_dirent of interest | |
64 | * | |
65 | * Unlink @sd from its sibling list which starts from | |
bc747f37 | 66 | * sd->s_parent->s_dir.children. |
0c73f18b TH |
67 | * |
68 | * Locking: | |
3007e997 | 69 | * mutex_lock(sysfs_mutex) |
0c73f18b | 70 | */ |
41fc1c27 | 71 | static void sysfs_unlink_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
72 | { |
73 | struct sysfs_dirent **pos; | |
74 | ||
bc747f37 TH |
75 | for (pos = &sd->s_parent->s_dir.children; *pos; |
76 | pos = &(*pos)->s_sibling) { | |
0c73f18b TH |
77 | if (*pos == sd) { |
78 | *pos = sd->s_sibling; | |
79 | sd->s_sibling = NULL; | |
80 | break; | |
81 | } | |
82 | } | |
83 | } | |
84 | ||
53e0ae92 TH |
85 | /** |
86 | * sysfs_get_dentry - get dentry for the given sysfs_dirent | |
87 | * @sd: sysfs_dirent of interest | |
88 | * | |
89 | * Get dentry for @sd. Dentry is looked up if currently not | |
e0712bbf TH |
90 | * present. This function descends from the root looking up |
91 | * dentry for each step. | |
53e0ae92 TH |
92 | * |
93 | * LOCKING: | |
932ea2e3 | 94 | * mutex_lock(sysfs_rename_mutex) |
53e0ae92 TH |
95 | * |
96 | * RETURNS: | |
97 | * Pointer to found dentry on success, ERR_PTR() value on error. | |
98 | */ | |
99 | struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd) | |
100 | { | |
e0712bbf | 101 | struct dentry *dentry = dget(sysfs_sb->s_root); |
53e0ae92 | 102 | |
e0712bbf TH |
103 | while (dentry->d_fsdata != sd) { |
104 | struct sysfs_dirent *cur; | |
105 | struct dentry *parent; | |
53e0ae92 | 106 | |
e0712bbf TH |
107 | /* find the first ancestor which hasn't been looked up */ |
108 | cur = sd; | |
109 | while (cur->s_parent != dentry->d_fsdata) | |
53e0ae92 TH |
110 | cur = cur->s_parent; |
111 | ||
53e0ae92 | 112 | /* look it up */ |
e0712bbf TH |
113 | parent = dentry; |
114 | mutex_lock(&parent->d_inode->i_mutex); | |
eead1911 | 115 | dentry = lookup_one_noperm(cur->s_name, parent); |
e0712bbf TH |
116 | mutex_unlock(&parent->d_inode->i_mutex); |
117 | dput(parent); | |
53e0ae92 | 118 | |
e0712bbf TH |
119 | if (IS_ERR(dentry)) |
120 | break; | |
53e0ae92 | 121 | } |
53e0ae92 TH |
122 | return dentry; |
123 | } | |
124 | ||
b6b4a439 TH |
125 | /** |
126 | * sysfs_get_active - get an active reference to sysfs_dirent | |
127 | * @sd: sysfs_dirent to get an active reference to | |
128 | * | |
129 | * Get an active reference of @sd. This function is noop if @sd | |
130 | * is NULL. | |
131 | * | |
132 | * RETURNS: | |
133 | * Pointer to @sd on success, NULL on failure. | |
134 | */ | |
78e9d367 | 135 | static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) |
b6b4a439 | 136 | { |
8619f979 TH |
137 | if (unlikely(!sd)) |
138 | return NULL; | |
139 | ||
140 | while (1) { | |
141 | int v, t; | |
142 | ||
143 | v = atomic_read(&sd->s_active); | |
144 | if (unlikely(v < 0)) | |
145 | return NULL; | |
146 | ||
147 | t = atomic_cmpxchg(&sd->s_active, v, v + 1); | |
148 | if (likely(t == v)) | |
149 | return sd; | |
150 | if (t < 0) | |
151 | return NULL; | |
152 | ||
153 | cpu_relax(); | |
b6b4a439 | 154 | } |
b6b4a439 TH |
155 | } |
156 | ||
157 | /** | |
158 | * sysfs_put_active - put an active reference to sysfs_dirent | |
159 | * @sd: sysfs_dirent to put an active reference to | |
160 | * | |
161 | * Put an active reference to @sd. This function is noop if @sd | |
162 | * is NULL. | |
163 | */ | |
78e9d367 | 164 | static void sysfs_put_active(struct sysfs_dirent *sd) |
b6b4a439 | 165 | { |
8619f979 TH |
166 | struct completion *cmpl; |
167 | int v; | |
168 | ||
169 | if (unlikely(!sd)) | |
170 | return; | |
171 | ||
172 | v = atomic_dec_return(&sd->s_active); | |
173 | if (likely(v != SD_DEACTIVATED_BIAS)) | |
174 | return; | |
175 | ||
176 | /* atomic_dec_return() is a mb(), we'll always see the updated | |
0c73f18b | 177 | * sd->s_sibling. |
8619f979 | 178 | */ |
0c73f18b | 179 | cmpl = (void *)sd->s_sibling; |
8619f979 | 180 | complete(cmpl); |
b6b4a439 TH |
181 | } |
182 | ||
183 | /** | |
184 | * sysfs_get_active_two - get active references to sysfs_dirent and parent | |
185 | * @sd: sysfs_dirent of interest | |
186 | * | |
187 | * Get active reference to @sd and its parent. Parent's active | |
188 | * reference is grabbed first. This function is noop if @sd is | |
189 | * NULL. | |
190 | * | |
191 | * RETURNS: | |
192 | * Pointer to @sd on success, NULL on failure. | |
193 | */ | |
194 | struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) | |
195 | { | |
196 | if (sd) { | |
197 | if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) | |
198 | return NULL; | |
199 | if (unlikely(!sysfs_get_active(sd))) { | |
200 | sysfs_put_active(sd->s_parent); | |
201 | return NULL; | |
202 | } | |
203 | } | |
204 | return sd; | |
205 | } | |
206 | ||
207 | /** | |
208 | * sysfs_put_active_two - put active references to sysfs_dirent and parent | |
209 | * @sd: sysfs_dirent of interest | |
210 | * | |
211 | * Put active references to @sd and its parent. This function is | |
212 | * noop if @sd is NULL. | |
213 | */ | |
214 | void sysfs_put_active_two(struct sysfs_dirent *sd) | |
215 | { | |
216 | if (sd) { | |
217 | sysfs_put_active(sd); | |
218 | sysfs_put_active(sd->s_parent); | |
219 | } | |
220 | } | |
221 | ||
222 | /** | |
223 | * sysfs_deactivate - deactivate sysfs_dirent | |
224 | * @sd: sysfs_dirent to deactivate | |
225 | * | |
8619f979 | 226 | * Deny new active references and drain existing ones. |
b6b4a439 | 227 | */ |
fb6896da | 228 | static void sysfs_deactivate(struct sysfs_dirent *sd) |
b6b4a439 | 229 | { |
8619f979 TH |
230 | DECLARE_COMPLETION_ONSTACK(wait); |
231 | int v; | |
b6b4a439 | 232 | |
380e6fbb | 233 | BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
0c73f18b | 234 | sd->s_sibling = (void *)&wait; |
8619f979 TH |
235 | |
236 | /* atomic_add_return() is a mb(), put_active() will always see | |
0c73f18b | 237 | * the updated sd->s_sibling. |
b6b4a439 | 238 | */ |
8619f979 TH |
239 | v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
240 | ||
241 | if (v != SD_DEACTIVATED_BIAS) | |
242 | wait_for_completion(&wait); | |
243 | ||
0c73f18b | 244 | sd->s_sibling = NULL; |
b6b4a439 TH |
245 | } |
246 | ||
42b37df6 | 247 | static int sysfs_alloc_ino(ino_t *pino) |
2b611bb7 TH |
248 | { |
249 | int ino, rc; | |
250 | ||
251 | retry: | |
252 | spin_lock(&sysfs_ino_lock); | |
253 | rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); | |
254 | spin_unlock(&sysfs_ino_lock); | |
255 | ||
256 | if (rc == -EAGAIN) { | |
257 | if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) | |
258 | goto retry; | |
259 | rc = -ENOMEM; | |
260 | } | |
261 | ||
262 | *pino = ino; | |
263 | return rc; | |
264 | } | |
265 | ||
266 | static void sysfs_free_ino(ino_t ino) | |
267 | { | |
268 | spin_lock(&sysfs_ino_lock); | |
269 | ida_remove(&sysfs_ino_ida, ino); | |
270 | spin_unlock(&sysfs_ino_lock); | |
271 | } | |
272 | ||
fa7f912a TH |
273 | void release_sysfs_dirent(struct sysfs_dirent * sd) |
274 | { | |
13b3086d TH |
275 | struct sysfs_dirent *parent_sd; |
276 | ||
277 | repeat: | |
3007e997 TH |
278 | /* Moving/renaming is always done while holding reference. |
279 | * sd->s_parent won't change beneath us. | |
280 | */ | |
13b3086d TH |
281 | parent_sd = sd->s_parent; |
282 | ||
b402d72c | 283 | if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
b1fc3d61 | 284 | sysfs_put(sd->s_symlink.target_sd); |
b402d72c | 285 | if (sysfs_type(sd) & SYSFS_COPY_NAME) |
0c096b50 | 286 | kfree(sd->s_name); |
fa7f912a | 287 | kfree(sd->s_iattr); |
2b611bb7 | 288 | sysfs_free_ino(sd->s_ino); |
fa7f912a | 289 | kmem_cache_free(sysfs_dir_cachep, sd); |
13b3086d TH |
290 | |
291 | sd = parent_sd; | |
292 | if (sd && atomic_dec_and_test(&sd->s_count)) | |
293 | goto repeat; | |
fa7f912a TH |
294 | } |
295 | ||
1da177e4 LT |
296 | static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) |
297 | { | |
298 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
299 | ||
5a26b79c | 300 | sysfs_put(sd); |
1da177e4 LT |
301 | iput(inode); |
302 | } | |
303 | ||
304 | static struct dentry_operations sysfs_dentry_ops = { | |
305 | .d_iput = sysfs_d_iput, | |
306 | }; | |
307 | ||
3e519038 | 308 | struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
1da177e4 | 309 | { |
0c096b50 | 310 | char *dup_name = NULL; |
01da2425 | 311 | struct sysfs_dirent *sd; |
0c096b50 TH |
312 | |
313 | if (type & SYSFS_COPY_NAME) { | |
314 | name = dup_name = kstrdup(name, GFP_KERNEL); | |
315 | if (!name) | |
01da2425 | 316 | return NULL; |
0c096b50 | 317 | } |
1da177e4 | 318 | |
c3762229 | 319 | sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
1da177e4 | 320 | if (!sd) |
01da2425 | 321 | goto err_out1; |
1da177e4 | 322 | |
0c096b50 | 323 | if (sysfs_alloc_ino(&sd->s_ino)) |
01da2425 | 324 | goto err_out2; |
2b611bb7 | 325 | |
1da177e4 | 326 | atomic_set(&sd->s_count, 1); |
8619f979 | 327 | atomic_set(&sd->s_active, 0); |
a26cd722 | 328 | |
0c096b50 | 329 | sd->s_name = name; |
a26cd722 | 330 | sd->s_mode = mode; |
b402d72c | 331 | sd->s_flags = type; |
1da177e4 LT |
332 | |
333 | return sd; | |
0c096b50 | 334 | |
01da2425 | 335 | err_out2: |
0c096b50 | 336 | kmem_cache_free(sysfs_dir_cachep, sd); |
01da2425 AM |
337 | err_out1: |
338 | kfree(dup_name); | |
0c096b50 | 339 | return NULL; |
1da177e4 LT |
340 | } |
341 | ||
fb6896da TH |
342 | static int sysfs_ilookup_test(struct inode *inode, void *arg) |
343 | { | |
344 | struct sysfs_dirent *sd = arg; | |
345 | return inode->i_ino == sd->s_ino; | |
346 | } | |
347 | ||
3007e997 | 348 | /** |
fb6896da TH |
349 | * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
350 | * @acxt: pointer to sysfs_addrm_cxt to be used | |
351 | * @parent_sd: parent sysfs_dirent | |
3007e997 | 352 | * |
fb6896da TH |
353 | * This function is called when the caller is about to add or |
354 | * remove sysfs_dirent under @parent_sd. This function acquires | |
355 | * sysfs_mutex, grabs inode for @parent_sd if available and lock | |
356 | * i_mutex of it. @acxt is used to keep and pass context to | |
357 | * other addrm functions. | |
3007e997 TH |
358 | * |
359 | * LOCKING: | |
fb6896da TH |
360 | * Kernel thread context (may sleep). sysfs_mutex is locked on |
361 | * return. i_mutex of parent inode is locked on return if | |
362 | * available. | |
3007e997 | 363 | */ |
fb6896da TH |
364 | void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
365 | struct sysfs_dirent *parent_sd) | |
b592fcfe | 366 | { |
fb6896da | 367 | struct inode *inode; |
b592fcfe | 368 | |
fb6896da TH |
369 | memset(acxt, 0, sizeof(*acxt)); |
370 | acxt->parent_sd = parent_sd; | |
371 | ||
372 | /* Lookup parent inode. inode initialization and I_NEW | |
373 | * clearing are protected by sysfs_mutex. By grabbing it and | |
374 | * looking up with _nowait variant, inode state can be | |
375 | * determined reliably. | |
376 | */ | |
377 | mutex_lock(&sysfs_mutex); | |
378 | ||
379 | inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test, | |
380 | parent_sd); | |
381 | ||
382 | if (inode && !(inode->i_state & I_NEW)) { | |
383 | /* parent inode available */ | |
384 | acxt->parent_inode = inode; | |
385 | ||
386 | /* sysfs_mutex is below i_mutex in lock hierarchy. | |
387 | * First, trylock i_mutex. If fails, unlock | |
388 | * sysfs_mutex and lock them in order. | |
389 | */ | |
390 | if (!mutex_trylock(&inode->i_mutex)) { | |
391 | mutex_unlock(&sysfs_mutex); | |
392 | mutex_lock(&inode->i_mutex); | |
393 | mutex_lock(&sysfs_mutex); | |
394 | } | |
395 | } else | |
396 | iput(inode); | |
397 | } | |
398 | ||
399 | /** | |
400 | * sysfs_add_one - add sysfs_dirent to parent | |
401 | * @acxt: addrm context to use | |
402 | * @sd: sysfs_dirent to be added | |
403 | * | |
404 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
181b2e4b TH |
405 | * nlink of parent inode if @sd is a directory and link into the |
406 | * children list of the parent. | |
fb6896da TH |
407 | * |
408 | * This function should be called between calls to | |
409 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
410 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
411 | * | |
412 | * LOCKING: | |
413 | * Determined by sysfs_addrm_start(). | |
23dc2799 TH |
414 | * |
415 | * RETURNS: | |
416 | * 0 on success, -EEXIST if entry with the given name already | |
417 | * exists. | |
fb6896da | 418 | */ |
23dc2799 | 419 | int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
fb6896da | 420 | { |
5c3e8964 GKH |
421 | if (sysfs_find_dirent(acxt->parent_sd, sd->s_name)) { |
422 | printk(KERN_WARNING "sysfs: duplicate filename '%s' " | |
423 | "can not be created\n", sd->s_name); | |
424 | WARN_ON(1); | |
23dc2799 | 425 | return -EEXIST; |
5c3e8964 | 426 | } |
23dc2799 | 427 | |
fb6896da TH |
428 | sd->s_parent = sysfs_get(acxt->parent_sd); |
429 | ||
430 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
431 | inc_nlink(acxt->parent_inode); | |
432 | ||
433 | acxt->cnt++; | |
41fc1c27 TH |
434 | |
435 | sysfs_link_sibling(sd); | |
23dc2799 TH |
436 | |
437 | return 0; | |
fb6896da TH |
438 | } |
439 | ||
440 | /** | |
441 | * sysfs_remove_one - remove sysfs_dirent from parent | |
442 | * @acxt: addrm context to use | |
443 | * @sd: sysfs_dirent to be added | |
444 | * | |
445 | * Mark @sd removed and drop nlink of parent inode if @sd is a | |
181b2e4b | 446 | * directory. @sd is unlinked from the children list. |
fb6896da TH |
447 | * |
448 | * This function should be called between calls to | |
449 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
450 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
451 | * | |
452 | * LOCKING: | |
453 | * Determined by sysfs_addrm_start(). | |
454 | */ | |
455 | void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
456 | { | |
41fc1c27 TH |
457 | BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED); |
458 | ||
459 | sysfs_unlink_sibling(sd); | |
fb6896da TH |
460 | |
461 | sd->s_flags |= SYSFS_FLAG_REMOVED; | |
462 | sd->s_sibling = acxt->removed; | |
463 | acxt->removed = sd; | |
464 | ||
465 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
466 | drop_nlink(acxt->parent_inode); | |
467 | ||
468 | acxt->cnt++; | |
469 | } | |
470 | ||
a0edd7c8 TH |
471 | /** |
472 | * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent | |
473 | * @sd: target sysfs_dirent | |
474 | * | |
475 | * Drop dentry for @sd. @sd must have been unlinked from its | |
476 | * parent on entry to this function such that it can't be looked | |
477 | * up anymore. | |
a0edd7c8 TH |
478 | */ |
479 | static void sysfs_drop_dentry(struct sysfs_dirent *sd) | |
480 | { | |
a0edd7c8 | 481 | struct inode *inode; |
89bec097 EB |
482 | struct dentry *dentry; |
483 | ||
484 | inode = ilookup(sysfs_sb, sd->s_ino); | |
485 | if (!inode) | |
486 | return; | |
a0edd7c8 | 487 | |
89bec097 EB |
488 | /* Drop any existing dentries associated with sd. |
489 | * | |
490 | * For the dentry to be properly freed we need to grab a | |
491 | * reference to the dentry under the dcache lock, unhash it, | |
492 | * and then put it. The playing with the dentry count allows | |
493 | * dput to immediately free the dentry if it is not in use. | |
a0edd7c8 | 494 | */ |
89bec097 | 495 | repeat: |
a0edd7c8 | 496 | spin_lock(&dcache_lock); |
89bec097 EB |
497 | list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
498 | if (d_unhashed(dentry)) | |
499 | continue; | |
500 | dget_locked(dentry); | |
a0edd7c8 TH |
501 | spin_lock(&dentry->d_lock); |
502 | __d_drop(dentry); | |
503 | spin_unlock(&dentry->d_lock); | |
89bec097 EB |
504 | spin_unlock(&dcache_lock); |
505 | dput(dentry); | |
506 | goto repeat; | |
a0edd7c8 | 507 | } |
a0edd7c8 | 508 | spin_unlock(&dcache_lock); |
a0edd7c8 TH |
509 | |
510 | /* adjust nlink and update timestamp */ | |
89bec097 | 511 | mutex_lock(&inode->i_mutex); |
a0edd7c8 | 512 | |
89bec097 EB |
513 | inode->i_ctime = CURRENT_TIME; |
514 | drop_nlink(inode); | |
515 | if (sysfs_type(sd) == SYSFS_DIR) | |
a0edd7c8 | 516 | drop_nlink(inode); |
a0edd7c8 | 517 | |
89bec097 EB |
518 | mutex_unlock(&inode->i_mutex); |
519 | ||
520 | iput(inode); | |
a0edd7c8 TH |
521 | } |
522 | ||
fb6896da TH |
523 | /** |
524 | * sysfs_addrm_finish - finish up sysfs_dirent add/remove | |
525 | * @acxt: addrm context to finish up | |
526 | * | |
527 | * Finish up sysfs_dirent add/remove. Resources acquired by | |
528 | * sysfs_addrm_start() are released and removed sysfs_dirents are | |
529 | * cleaned up. Timestamps on the parent inode are updated. | |
530 | * | |
531 | * LOCKING: | |
532 | * All mutexes acquired by sysfs_addrm_start() are released. | |
fb6896da | 533 | */ |
990e53f8 | 534 | void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) |
fb6896da TH |
535 | { |
536 | /* release resources acquired by sysfs_addrm_start() */ | |
537 | mutex_unlock(&sysfs_mutex); | |
538 | if (acxt->parent_inode) { | |
539 | struct inode *inode = acxt->parent_inode; | |
540 | ||
541 | /* if added/removed, update timestamps on the parent */ | |
542 | if (acxt->cnt) | |
543 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
544 | ||
545 | mutex_unlock(&inode->i_mutex); | |
546 | iput(inode); | |
547 | } | |
548 | ||
549 | /* kill removed sysfs_dirents */ | |
550 | while (acxt->removed) { | |
551 | struct sysfs_dirent *sd = acxt->removed; | |
552 | ||
553 | acxt->removed = sd->s_sibling; | |
554 | sd->s_sibling = NULL; | |
555 | ||
556 | sysfs_drop_dentry(sd); | |
557 | sysfs_deactivate(sd); | |
558 | sysfs_put(sd); | |
13b3086d | 559 | } |
b592fcfe EB |
560 | } |
561 | ||
f0b0af47 TH |
562 | /** |
563 | * sysfs_find_dirent - find sysfs_dirent with the given name | |
564 | * @parent_sd: sysfs_dirent to search under | |
565 | * @name: name to look for | |
566 | * | |
567 | * Look for sysfs_dirent with name @name under @parent_sd. | |
c516865c | 568 | * |
f0b0af47 | 569 | * LOCKING: |
3007e997 | 570 | * mutex_lock(sysfs_mutex) |
c516865c | 571 | * |
f0b0af47 TH |
572 | * RETURNS: |
573 | * Pointer to sysfs_dirent if found, NULL if not. | |
c516865c | 574 | */ |
f0b0af47 TH |
575 | struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, |
576 | const unsigned char *name) | |
c516865c | 577 | { |
f0b0af47 TH |
578 | struct sysfs_dirent *sd; |
579 | ||
bc747f37 | 580 | for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) |
3efa65b9 | 581 | if (!strcmp(sd->s_name, name)) |
f0b0af47 TH |
582 | return sd; |
583 | return NULL; | |
584 | } | |
c516865c | 585 | |
f0b0af47 TH |
586 | /** |
587 | * sysfs_get_dirent - find and get sysfs_dirent with the given name | |
588 | * @parent_sd: sysfs_dirent to search under | |
589 | * @name: name to look for | |
590 | * | |
591 | * Look for sysfs_dirent with name @name under @parent_sd and get | |
592 | * it if found. | |
593 | * | |
594 | * LOCKING: | |
3007e997 | 595 | * Kernel thread context (may sleep). Grabs sysfs_mutex. |
f0b0af47 TH |
596 | * |
597 | * RETURNS: | |
598 | * Pointer to sysfs_dirent if found, NULL if not. | |
599 | */ | |
600 | struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, | |
601 | const unsigned char *name) | |
602 | { | |
603 | struct sysfs_dirent *sd; | |
604 | ||
3007e997 | 605 | mutex_lock(&sysfs_mutex); |
f0b0af47 TH |
606 | sd = sysfs_find_dirent(parent_sd, name); |
607 | sysfs_get(sd); | |
3007e997 | 608 | mutex_unlock(&sysfs_mutex); |
f0b0af47 TH |
609 | |
610 | return sd; | |
c516865c MS |
611 | } |
612 | ||
608e266a TH |
613 | static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
614 | const char *name, struct sysfs_dirent **p_sd) | |
1da177e4 | 615 | { |
1da177e4 | 616 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
51225039 | 617 | struct sysfs_addrm_cxt acxt; |
dfeb9fb0 | 618 | struct sysfs_dirent *sd; |
23dc2799 | 619 | int rc; |
1da177e4 | 620 | |
fc9f54b9 | 621 | /* allocate */ |
3e519038 | 622 | sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
a26cd722 | 623 | if (!sd) |
51225039 | 624 | return -ENOMEM; |
b1fc3d61 | 625 | sd->s_dir.kobj = kobj; |
dfeb9fb0 | 626 | |
fc9f54b9 | 627 | /* link in */ |
51225039 | 628 | sysfs_addrm_start(&acxt, parent_sd); |
23dc2799 TH |
629 | rc = sysfs_add_one(&acxt, sd); |
630 | sysfs_addrm_finish(&acxt); | |
967e35dc | 631 | |
23dc2799 TH |
632 | if (rc == 0) |
633 | *p_sd = sd; | |
634 | else | |
967e35dc | 635 | sysfs_put(sd); |
dfeb9fb0 | 636 | |
23dc2799 | 637 | return rc; |
1da177e4 LT |
638 | } |
639 | ||
608e266a TH |
640 | int sysfs_create_subdir(struct kobject *kobj, const char *name, |
641 | struct sysfs_dirent **p_sd) | |
1da177e4 | 642 | { |
608e266a | 643 | return create_dir(kobj, kobj->sd, name, p_sd); |
1da177e4 LT |
644 | } |
645 | ||
646 | /** | |
647 | * sysfs_create_dir - create a directory for an object. | |
1da177e4 LT |
648 | * @kobj: object we're creating directory for. |
649 | */ | |
90bc6135 | 650 | int sysfs_create_dir(struct kobject * kobj) |
1da177e4 | 651 | { |
608e266a | 652 | struct sysfs_dirent *parent_sd, *sd; |
1da177e4 LT |
653 | int error = 0; |
654 | ||
655 | BUG_ON(!kobj); | |
656 | ||
90bc6135 | 657 | if (kobj->parent) |
608e266a | 658 | parent_sd = kobj->parent->sd; |
1da177e4 | 659 | else |
7d0c7d67 | 660 | parent_sd = &sysfs_root; |
1da177e4 | 661 | |
608e266a | 662 | error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd); |
1da177e4 | 663 | if (!error) |
608e266a | 664 | kobj->sd = sd; |
1da177e4 LT |
665 | return error; |
666 | } | |
667 | ||
1da177e4 LT |
668 | static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
669 | struct nameidata *nd) | |
670 | { | |
6cb52147 | 671 | struct dentry *ret = NULL; |
a7a04754 TH |
672 | struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata; |
673 | struct sysfs_dirent *sd; | |
fc9f54b9 | 674 | struct inode *inode; |
1da177e4 | 675 | |
6cb52147 TH |
676 | mutex_lock(&sysfs_mutex); |
677 | ||
94777e09 | 678 | sd = sysfs_find_dirent(parent_sd, dentry->d_name.name); |
1da177e4 | 679 | |
fc9f54b9 | 680 | /* no such entry */ |
e49452c6 TH |
681 | if (!sd) { |
682 | ret = ERR_PTR(-ENOENT); | |
6cb52147 | 683 | goto out_unlock; |
e49452c6 | 684 | } |
fc9f54b9 TH |
685 | |
686 | /* attach dentry and inode */ | |
8312a8d7 | 687 | inode = sysfs_get_inode(sd); |
6cb52147 TH |
688 | if (!inode) { |
689 | ret = ERR_PTR(-ENOMEM); | |
690 | goto out_unlock; | |
691 | } | |
3007e997 | 692 | |
d6b4fd2f TH |
693 | /* instantiate and hash dentry */ |
694 | dentry->d_op = &sysfs_dentry_ops; | |
695 | dentry->d_fsdata = sysfs_get(sd); | |
119dd52b | 696 | d_instantiate(dentry, inode); |
d6b4fd2f | 697 | d_rehash(dentry); |
fc9f54b9 | 698 | |
6cb52147 | 699 | out_unlock: |
3007e997 | 700 | mutex_unlock(&sysfs_mutex); |
6cb52147 | 701 | return ret; |
1da177e4 LT |
702 | } |
703 | ||
c5ef1c42 | 704 | const struct inode_operations sysfs_dir_inode_operations = { |
1da177e4 | 705 | .lookup = sysfs_lookup, |
988d186d | 706 | .setattr = sysfs_setattr, |
1da177e4 LT |
707 | }; |
708 | ||
608e266a | 709 | static void remove_dir(struct sysfs_dirent *sd) |
1da177e4 | 710 | { |
fb6896da | 711 | struct sysfs_addrm_cxt acxt; |
1da177e4 | 712 | |
fb6896da | 713 | sysfs_addrm_start(&acxt, sd->s_parent); |
fb6896da TH |
714 | sysfs_remove_one(&acxt, sd); |
715 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
716 | } |
717 | ||
608e266a | 718 | void sysfs_remove_subdir(struct sysfs_dirent *sd) |
1da177e4 | 719 | { |
608e266a | 720 | remove_dir(sd); |
1da177e4 LT |
721 | } |
722 | ||
723 | ||
608e266a | 724 | static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
1da177e4 | 725 | { |
fb6896da | 726 | struct sysfs_addrm_cxt acxt; |
0c73f18b | 727 | struct sysfs_dirent **pos; |
1da177e4 | 728 | |
608e266a | 729 | if (!dir_sd) |
1da177e4 LT |
730 | return; |
731 | ||
608e266a | 732 | pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
fb6896da | 733 | sysfs_addrm_start(&acxt, dir_sd); |
bc747f37 | 734 | pos = &dir_sd->s_dir.children; |
0c73f18b TH |
735 | while (*pos) { |
736 | struct sysfs_dirent *sd = *pos; | |
737 | ||
3efa65b9 | 738 | if (sysfs_type(sd) != SYSFS_DIR) |
fb6896da | 739 | sysfs_remove_one(&acxt, sd); |
41fc1c27 | 740 | else |
0c73f18b | 741 | pos = &(*pos)->s_sibling; |
1da177e4 | 742 | } |
fb6896da | 743 | sysfs_addrm_finish(&acxt); |
0ab66088 | 744 | |
608e266a | 745 | remove_dir(dir_sd); |
b592fcfe EB |
746 | } |
747 | ||
748 | /** | |
749 | * sysfs_remove_dir - remove an object's directory. | |
750 | * @kobj: object. | |
751 | * | |
752 | * The only thing special about this is that we remove any files in | |
753 | * the directory before we remove the directory, and we've inlined | |
754 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
755 | */ | |
756 | ||
757 | void sysfs_remove_dir(struct kobject * kobj) | |
758 | { | |
608e266a | 759 | struct sysfs_dirent *sd = kobj->sd; |
aecdceda | 760 | |
5f995323 | 761 | spin_lock(&sysfs_assoc_lock); |
608e266a | 762 | kobj->sd = NULL; |
5f995323 | 763 | spin_unlock(&sysfs_assoc_lock); |
aecdceda | 764 | |
608e266a | 765 | __sysfs_remove_dir(sd); |
1da177e4 LT |
766 | } |
767 | ||
90bc6135 | 768 | int sysfs_rename_dir(struct kobject * kobj, const char *new_name) |
1da177e4 | 769 | { |
9918f9a4 | 770 | struct sysfs_dirent *sd = kobj->sd; |
90bc6135 | 771 | struct dentry *parent = NULL; |
51225039 TH |
772 | struct dentry *old_dentry = NULL, *new_dentry = NULL; |
773 | const char *dup_name = NULL; | |
996b7376 | 774 | int error; |
1da177e4 | 775 | |
932ea2e3 EB |
776 | mutex_lock(&sysfs_rename_mutex); |
777 | ||
9918f9a4 EB |
778 | error = 0; |
779 | if (strcmp(sd->s_name, new_name) == 0) | |
780 | goto out; /* nothing to rename */ | |
781 | ||
ff869de7 | 782 | /* get the original dentry */ |
51225039 TH |
783 | old_dentry = sysfs_get_dentry(sd); |
784 | if (IS_ERR(old_dentry)) { | |
785 | error = PTR_ERR(old_dentry); | |
456ef155 | 786 | old_dentry = NULL; |
9918f9a4 | 787 | goto out; |
51225039 TH |
788 | } |
789 | ||
ff869de7 | 790 | parent = old_dentry->d_parent; |
1da177e4 | 791 | |
90bc6135 EB |
792 | /* lock parent and get dentry for new name */ |
793 | mutex_lock(&parent->d_inode->i_mutex); | |
9918f9a4 | 794 | mutex_lock(&sysfs_mutex); |
1da177e4 | 795 | |
9918f9a4 EB |
796 | error = -EEXIST; |
797 | if (sysfs_find_dirent(sd->s_parent, new_name)) | |
51225039 | 798 | goto out_unlock; |
996b7376 | 799 | |
9918f9a4 EB |
800 | error = -ENOMEM; |
801 | new_dentry = d_alloc_name(parent, new_name); | |
802 | if (!new_dentry) | |
51225039 | 803 | goto out_unlock; |
996b7376 | 804 | |
0c096b50 TH |
805 | /* rename kobject and sysfs_dirent */ |
806 | error = -ENOMEM; | |
807 | new_name = dup_name = kstrdup(new_name, GFP_KERNEL); | |
808 | if (!new_name) | |
9918f9a4 | 809 | goto out_unlock; |
0c096b50 | 810 | |
996b7376 TH |
811 | error = kobject_set_name(kobj, "%s", new_name); |
812 | if (error) | |
9918f9a4 | 813 | goto out_unlock; |
996b7376 | 814 | |
51225039 | 815 | dup_name = sd->s_name; |
0c096b50 TH |
816 | sd->s_name = new_name; |
817 | ||
ff869de7 | 818 | /* rename */ |
996b7376 | 819 | d_add(new_dentry, NULL); |
5a26b79c | 820 | d_move(old_dentry, new_dentry); |
996b7376 | 821 | |
996b7376 | 822 | error = 0; |
996b7376 | 823 | out_unlock: |
9918f9a4 | 824 | mutex_unlock(&sysfs_mutex); |
90bc6135 | 825 | mutex_unlock(&parent->d_inode->i_mutex); |
51225039 | 826 | kfree(dup_name); |
51225039 TH |
827 | dput(old_dentry); |
828 | dput(new_dentry); | |
9918f9a4 | 829 | out: |
932ea2e3 | 830 | mutex_unlock(&sysfs_rename_mutex); |
1da177e4 LT |
831 | return error; |
832 | } | |
833 | ||
51225039 | 834 | int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) |
8a82472f | 835 | { |
51225039 TH |
836 | struct sysfs_dirent *sd = kobj->sd; |
837 | struct sysfs_dirent *new_parent_sd; | |
838 | struct dentry *old_parent, *new_parent = NULL; | |
839 | struct dentry *old_dentry = NULL, *new_dentry = NULL; | |
8a82472f CH |
840 | int error; |
841 | ||
932ea2e3 | 842 | mutex_lock(&sysfs_rename_mutex); |
51225039 TH |
843 | BUG_ON(!sd->s_parent); |
844 | new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root; | |
845 | ||
45aaae9c EB |
846 | error = 0; |
847 | if (sd->s_parent == new_parent_sd) | |
848 | goto out; /* nothing to move */ | |
849 | ||
51225039 TH |
850 | /* get dentries */ |
851 | old_dentry = sysfs_get_dentry(sd); | |
852 | if (IS_ERR(old_dentry)) { | |
853 | error = PTR_ERR(old_dentry); | |
456ef155 | 854 | old_dentry = NULL; |
45aaae9c | 855 | goto out; |
51225039 | 856 | } |
5a26b79c | 857 | old_parent = old_dentry->d_parent; |
51225039 TH |
858 | |
859 | new_parent = sysfs_get_dentry(new_parent_sd); | |
860 | if (IS_ERR(new_parent)) { | |
861 | error = PTR_ERR(new_parent); | |
456ef155 | 862 | new_parent = NULL; |
45aaae9c | 863 | goto out; |
51225039 | 864 | } |
8a82472f CH |
865 | |
866 | again: | |
51225039 TH |
867 | mutex_lock(&old_parent->d_inode->i_mutex); |
868 | if (!mutex_trylock(&new_parent->d_inode->i_mutex)) { | |
869 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
8a82472f CH |
870 | goto again; |
871 | } | |
45aaae9c | 872 | mutex_lock(&sysfs_mutex); |
8a82472f | 873 | |
45aaae9c EB |
874 | error = -EEXIST; |
875 | if (sysfs_find_dirent(new_parent_sd, sd->s_name)) | |
51225039 | 876 | goto out_unlock; |
45aaae9c EB |
877 | |
878 | error = -ENOMEM; | |
879 | new_dentry = d_alloc_name(new_parent, sd->s_name); | |
880 | if (!new_dentry) | |
881 | goto out_unlock; | |
882 | ||
883 | error = 0; | |
8a82472f | 884 | d_add(new_dentry, NULL); |
5a26b79c | 885 | d_move(old_dentry, new_dentry); |
8a82472f CH |
886 | |
887 | /* Remove from old parent's list and insert into new parent's list. */ | |
0c73f18b | 888 | sysfs_unlink_sibling(sd); |
7f7cfffe TH |
889 | sysfs_get(new_parent_sd); |
890 | sysfs_put(sd->s_parent); | |
891 | sd->s_parent = new_parent_sd; | |
0c73f18b | 892 | sysfs_link_sibling(sd); |
8a82472f | 893 | |
51225039 | 894 | out_unlock: |
45aaae9c | 895 | mutex_unlock(&sysfs_mutex); |
51225039 TH |
896 | mutex_unlock(&new_parent->d_inode->i_mutex); |
897 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
45aaae9c | 898 | out: |
51225039 TH |
899 | dput(new_parent); |
900 | dput(old_dentry); | |
901 | dput(new_dentry); | |
932ea2e3 | 902 | mutex_unlock(&sysfs_rename_mutex); |
8a82472f CH |
903 | return error; |
904 | } | |
905 | ||
1da177e4 LT |
906 | /* Relationship between s_mode and the DT_xxx types */ |
907 | static inline unsigned char dt_type(struct sysfs_dirent *sd) | |
908 | { | |
909 | return (sd->s_mode >> 12) & 15; | |
910 | } | |
911 | ||
912 | static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
913 | { | |
f427f5d5 | 914 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 915 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
3efa65b9 | 916 | struct sysfs_dirent *pos; |
1da177e4 | 917 | ino_t ino; |
1da177e4 | 918 | |
3efa65b9 EB |
919 | if (filp->f_pos == 0) { |
920 | ino = parent_sd->s_ino; | |
921 | if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 922 | filp->f_pos++; |
3efa65b9 EB |
923 | } |
924 | if (filp->f_pos == 1) { | |
925 | if (parent_sd->s_parent) | |
926 | ino = parent_sd->s_parent->s_ino; | |
927 | else | |
928 | ino = parent_sd->s_ino; | |
929 | if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 930 | filp->f_pos++; |
3efa65b9 EB |
931 | } |
932 | if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) { | |
933 | mutex_lock(&sysfs_mutex); | |
0c73f18b | 934 | |
3efa65b9 | 935 | /* Skip the dentries we have already reported */ |
bc747f37 | 936 | pos = parent_sd->s_dir.children; |
3efa65b9 EB |
937 | while (pos && (filp->f_pos > pos->s_ino)) |
938 | pos = pos->s_sibling; | |
3007e997 | 939 | |
3efa65b9 EB |
940 | for ( ; pos; pos = pos->s_sibling) { |
941 | const char * name; | |
942 | int len; | |
1da177e4 | 943 | |
3efa65b9 EB |
944 | name = pos->s_name; |
945 | len = strlen(name); | |
946 | filp->f_pos = ino = pos->s_ino; | |
1da177e4 | 947 | |
3efa65b9 EB |
948 | if (filldir(dirent, name, len, filp->f_pos, ino, |
949 | dt_type(pos)) < 0) | |
1da177e4 | 950 | break; |
1da177e4 | 951 | } |
3efa65b9 EB |
952 | if (!pos) |
953 | filp->f_pos = INT_MAX; | |
3007e997 | 954 | mutex_unlock(&sysfs_mutex); |
1da177e4 | 955 | } |
3efa65b9 | 956 | return 0; |
1da177e4 LT |
957 | } |
958 | ||
3efa65b9 | 959 | |
4b6f5d20 | 960 | const struct file_operations sysfs_dir_operations = { |
1da177e4 LT |
961 | .read = generic_read_dir, |
962 | .readdir = sysfs_readdir, | |
963 | }; |