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> |
4c3da220 | 24 | #include <linux/security.h> |
1da177e4 LT |
25 | #include "sysfs.h" |
26 | ||
3007e997 | 27 | DEFINE_MUTEX(sysfs_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 | ||
b6b4a439 TH |
86 | /** |
87 | * sysfs_get_active - get an active reference to sysfs_dirent | |
88 | * @sd: sysfs_dirent to get an active reference to | |
89 | * | |
90 | * Get an active reference of @sd. This function is noop if @sd | |
91 | * is NULL. | |
92 | * | |
93 | * RETURNS: | |
94 | * Pointer to @sd on success, NULL on failure. | |
95 | */ | |
e72ceb8c | 96 | struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) |
b6b4a439 | 97 | { |
8619f979 TH |
98 | if (unlikely(!sd)) |
99 | return NULL; | |
100 | ||
101 | while (1) { | |
102 | int v, t; | |
103 | ||
104 | v = atomic_read(&sd->s_active); | |
105 | if (unlikely(v < 0)) | |
106 | return NULL; | |
107 | ||
108 | t = atomic_cmpxchg(&sd->s_active, v, v + 1); | |
846f9974 EB |
109 | if (likely(t == v)) { |
110 | rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); | |
8619f979 | 111 | return sd; |
846f9974 | 112 | } |
8619f979 TH |
113 | if (t < 0) |
114 | return NULL; | |
115 | ||
116 | cpu_relax(); | |
b6b4a439 | 117 | } |
b6b4a439 TH |
118 | } |
119 | ||
120 | /** | |
121 | * sysfs_put_active - put an active reference to sysfs_dirent | |
122 | * @sd: sysfs_dirent to put an active reference to | |
123 | * | |
124 | * Put an active reference to @sd. This function is noop if @sd | |
125 | * is NULL. | |
126 | */ | |
e72ceb8c | 127 | void sysfs_put_active(struct sysfs_dirent *sd) |
b6b4a439 | 128 | { |
8619f979 TH |
129 | struct completion *cmpl; |
130 | int v; | |
131 | ||
132 | if (unlikely(!sd)) | |
133 | return; | |
134 | ||
846f9974 | 135 | rwsem_release(&sd->dep_map, 1, _RET_IP_); |
8619f979 TH |
136 | v = atomic_dec_return(&sd->s_active); |
137 | if (likely(v != SD_DEACTIVATED_BIAS)) | |
138 | return; | |
139 | ||
140 | /* atomic_dec_return() is a mb(), we'll always see the updated | |
0c73f18b | 141 | * sd->s_sibling. |
8619f979 | 142 | */ |
0c73f18b | 143 | cmpl = (void *)sd->s_sibling; |
8619f979 | 144 | complete(cmpl); |
b6b4a439 TH |
145 | } |
146 | ||
b6b4a439 TH |
147 | /** |
148 | * sysfs_deactivate - deactivate sysfs_dirent | |
149 | * @sd: sysfs_dirent to deactivate | |
150 | * | |
8619f979 | 151 | * Deny new active references and drain existing ones. |
b6b4a439 | 152 | */ |
fb6896da | 153 | static void sysfs_deactivate(struct sysfs_dirent *sd) |
b6b4a439 | 154 | { |
8619f979 TH |
155 | DECLARE_COMPLETION_ONSTACK(wait); |
156 | int v; | |
b6b4a439 | 157 | |
380e6fbb | 158 | BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
a2db6842 EB |
159 | |
160 | if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF)) | |
161 | return; | |
162 | ||
0c73f18b | 163 | sd->s_sibling = (void *)&wait; |
8619f979 | 164 | |
846f9974 | 165 | rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_); |
8619f979 | 166 | /* atomic_add_return() is a mb(), put_active() will always see |
0c73f18b | 167 | * the updated sd->s_sibling. |
b6b4a439 | 168 | */ |
8619f979 TH |
169 | v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
170 | ||
846f9974 EB |
171 | if (v != SD_DEACTIVATED_BIAS) { |
172 | lock_contended(&sd->dep_map, _RET_IP_); | |
8619f979 | 173 | wait_for_completion(&wait); |
846f9974 | 174 | } |
8619f979 | 175 | |
0c73f18b | 176 | sd->s_sibling = NULL; |
846f9974 EB |
177 | |
178 | lock_acquired(&sd->dep_map, _RET_IP_); | |
179 | rwsem_release(&sd->dep_map, 1, _RET_IP_); | |
b6b4a439 TH |
180 | } |
181 | ||
42b37df6 | 182 | static int sysfs_alloc_ino(ino_t *pino) |
2b611bb7 TH |
183 | { |
184 | int ino, rc; | |
185 | ||
186 | retry: | |
187 | spin_lock(&sysfs_ino_lock); | |
188 | rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); | |
189 | spin_unlock(&sysfs_ino_lock); | |
190 | ||
191 | if (rc == -EAGAIN) { | |
192 | if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) | |
193 | goto retry; | |
194 | rc = -ENOMEM; | |
195 | } | |
196 | ||
197 | *pino = ino; | |
198 | return rc; | |
199 | } | |
200 | ||
201 | static void sysfs_free_ino(ino_t ino) | |
202 | { | |
203 | spin_lock(&sysfs_ino_lock); | |
204 | ida_remove(&sysfs_ino_ida, ino); | |
205 | spin_unlock(&sysfs_ino_lock); | |
206 | } | |
207 | ||
fa7f912a TH |
208 | void release_sysfs_dirent(struct sysfs_dirent * sd) |
209 | { | |
13b3086d TH |
210 | struct sysfs_dirent *parent_sd; |
211 | ||
212 | repeat: | |
3007e997 TH |
213 | /* Moving/renaming is always done while holding reference. |
214 | * sd->s_parent won't change beneath us. | |
215 | */ | |
13b3086d TH |
216 | parent_sd = sd->s_parent; |
217 | ||
b402d72c | 218 | if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
b1fc3d61 | 219 | sysfs_put(sd->s_symlink.target_sd); |
b402d72c | 220 | if (sysfs_type(sd) & SYSFS_COPY_NAME) |
0c096b50 | 221 | kfree(sd->s_name); |
4c3da220 EB |
222 | if (sd->s_iattr && sd->s_iattr->ia_secdata) |
223 | security_release_secctx(sd->s_iattr->ia_secdata, | |
224 | sd->s_iattr->ia_secdata_len); | |
fa7f912a | 225 | kfree(sd->s_iattr); |
2b611bb7 | 226 | sysfs_free_ino(sd->s_ino); |
fa7f912a | 227 | kmem_cache_free(sysfs_dir_cachep, sd); |
13b3086d TH |
228 | |
229 | sd = parent_sd; | |
230 | if (sd && atomic_dec_and_test(&sd->s_count)) | |
231 | goto repeat; | |
fa7f912a TH |
232 | } |
233 | ||
fe15ce44 | 234 | static int sysfs_dentry_delete(const struct dentry *dentry) |
e8f077c8 EB |
235 | { |
236 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
237 | return !!(sd->s_flags & SYSFS_FLAG_REMOVED); | |
238 | } | |
239 | ||
240 | static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd) | |
241 | { | |
34286d66 | 242 | struct sysfs_dirent *sd; |
e8f077c8 EB |
243 | int is_dir; |
244 | ||
34286d66 NP |
245 | if (nd->flags & LOOKUP_RCU) |
246 | return -ECHILD; | |
247 | ||
248 | sd = dentry->d_fsdata; | |
e8f077c8 EB |
249 | mutex_lock(&sysfs_mutex); |
250 | ||
251 | /* The sysfs dirent has been deleted */ | |
252 | if (sd->s_flags & SYSFS_FLAG_REMOVED) | |
253 | goto out_bad; | |
254 | ||
832b6af1 EB |
255 | /* The sysfs dirent has been moved? */ |
256 | if (dentry->d_parent->d_fsdata != sd->s_parent) | |
257 | goto out_bad; | |
258 | ||
259 | /* The sysfs dirent has been renamed */ | |
260 | if (strcmp(dentry->d_name.name, sd->s_name) != 0) | |
261 | goto out_bad; | |
262 | ||
e8f077c8 EB |
263 | mutex_unlock(&sysfs_mutex); |
264 | out_valid: | |
265 | return 1; | |
266 | out_bad: | |
267 | /* Remove the dentry from the dcache hashes. | |
268 | * If this is a deleted dentry we use d_drop instead of d_delete | |
269 | * so sysfs doesn't need to cope with negative dentries. | |
832b6af1 EB |
270 | * |
271 | * If this is a dentry that has simply been renamed we | |
272 | * use d_drop to remove it from the dcache lookup on its | |
273 | * old parent. If this dentry persists later when a lookup | |
274 | * is performed at its new name the dentry will be readded | |
275 | * to the dcache hashes. | |
e8f077c8 EB |
276 | */ |
277 | is_dir = (sysfs_type(sd) == SYSFS_DIR); | |
278 | mutex_unlock(&sysfs_mutex); | |
279 | if (is_dir) { | |
280 | /* If we have submounts we must allow the vfs caches | |
281 | * to lie about the state of the filesystem to prevent | |
282 | * leaks and other nasty things. | |
283 | */ | |
284 | if (have_submounts(dentry)) | |
285 | goto out_valid; | |
286 | shrink_dcache_parent(dentry); | |
287 | } | |
288 | d_drop(dentry); | |
289 | return 0; | |
290 | } | |
291 | ||
28a027cf | 292 | static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode) |
1da177e4 LT |
293 | { |
294 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
295 | ||
5a26b79c | 296 | sysfs_put(sd); |
1da177e4 LT |
297 | iput(inode); |
298 | } | |
299 | ||
ee1ec329 | 300 | static const struct dentry_operations sysfs_dentry_ops = { |
e8f077c8 EB |
301 | .d_revalidate = sysfs_dentry_revalidate, |
302 | .d_delete = sysfs_dentry_delete, | |
28a027cf | 303 | .d_iput = sysfs_dentry_iput, |
1da177e4 LT |
304 | }; |
305 | ||
3e519038 | 306 | struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
1da177e4 | 307 | { |
0c096b50 | 308 | char *dup_name = NULL; |
01da2425 | 309 | struct sysfs_dirent *sd; |
0c096b50 TH |
310 | |
311 | if (type & SYSFS_COPY_NAME) { | |
312 | name = dup_name = kstrdup(name, GFP_KERNEL); | |
313 | if (!name) | |
01da2425 | 314 | return NULL; |
0c096b50 | 315 | } |
1da177e4 | 316 | |
c3762229 | 317 | sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
1da177e4 | 318 | if (!sd) |
01da2425 | 319 | goto err_out1; |
1da177e4 | 320 | |
0c096b50 | 321 | if (sysfs_alloc_ino(&sd->s_ino)) |
01da2425 | 322 | goto err_out2; |
2b611bb7 | 323 | |
1da177e4 | 324 | atomic_set(&sd->s_count, 1); |
8619f979 | 325 | atomic_set(&sd->s_active, 0); |
a26cd722 | 326 | |
0c096b50 | 327 | sd->s_name = name; |
a26cd722 | 328 | sd->s_mode = mode; |
b402d72c | 329 | sd->s_flags = type; |
1da177e4 LT |
330 | |
331 | return sd; | |
0c096b50 | 332 | |
01da2425 | 333 | err_out2: |
0c096b50 | 334 | kmem_cache_free(sysfs_dir_cachep, sd); |
01da2425 AM |
335 | err_out1: |
336 | kfree(dup_name); | |
0c096b50 | 337 | return NULL; |
1da177e4 LT |
338 | } |
339 | ||
3007e997 | 340 | /** |
fb6896da TH |
341 | * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
342 | * @acxt: pointer to sysfs_addrm_cxt to be used | |
343 | * @parent_sd: parent sysfs_dirent | |
3007e997 | 344 | * |
fb6896da TH |
345 | * This function is called when the caller is about to add or |
346 | * remove sysfs_dirent under @parent_sd. This function acquires | |
a16bbc34 | 347 | * sysfs_mutex. @acxt is used to keep and pass context to |
fb6896da | 348 | * other addrm functions. |
3007e997 TH |
349 | * |
350 | * LOCKING: | |
fb6896da | 351 | * Kernel thread context (may sleep). sysfs_mutex is locked on |
a16bbc34 | 352 | * return. |
3007e997 | 353 | */ |
fb6896da TH |
354 | void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
355 | struct sysfs_dirent *parent_sd) | |
b592fcfe | 356 | { |
fb6896da TH |
357 | memset(acxt, 0, sizeof(*acxt)); |
358 | acxt->parent_sd = parent_sd; | |
359 | ||
fb6896da | 360 | mutex_lock(&sysfs_mutex); |
fb6896da TH |
361 | } |
362 | ||
363 | /** | |
36ce6dad | 364 | * __sysfs_add_one - add sysfs_dirent to parent without warning |
fb6896da TH |
365 | * @acxt: addrm context to use |
366 | * @sd: sysfs_dirent to be added | |
367 | * | |
368 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
181b2e4b TH |
369 | * nlink of parent inode if @sd is a directory and link into the |
370 | * children list of the parent. | |
fb6896da TH |
371 | * |
372 | * This function should be called between calls to | |
373 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
374 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
375 | * | |
376 | * LOCKING: | |
377 | * Determined by sysfs_addrm_start(). | |
23dc2799 TH |
378 | * |
379 | * RETURNS: | |
380 | * 0 on success, -EEXIST if entry with the given name already | |
381 | * exists. | |
fb6896da | 382 | */ |
36ce6dad | 383 | int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
fb6896da | 384 | { |
6b0bfe93 EB |
385 | struct sysfs_inode_attrs *ps_iattr; |
386 | ||
3ff195b0 | 387 | if (sysfs_find_dirent(acxt->parent_sd, sd->s_ns, sd->s_name)) |
23dc2799 TH |
388 | return -EEXIST; |
389 | ||
fb6896da TH |
390 | sd->s_parent = sysfs_get(acxt->parent_sd); |
391 | ||
41fc1c27 | 392 | sysfs_link_sibling(sd); |
23dc2799 | 393 | |
6b0bfe93 EB |
394 | /* Update timestamps on the parent */ |
395 | ps_iattr = acxt->parent_sd->s_iattr; | |
396 | if (ps_iattr) { | |
397 | struct iattr *ps_iattrs = &ps_iattr->ia_iattr; | |
398 | ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; | |
399 | } | |
400 | ||
23dc2799 | 401 | return 0; |
fb6896da TH |
402 | } |
403 | ||
425cb029 AC |
404 | /** |
405 | * sysfs_pathname - return full path to sysfs dirent | |
406 | * @sd: sysfs_dirent whose path we want | |
407 | * @path: caller allocated buffer | |
408 | * | |
409 | * Gives the name "/" to the sysfs_root entry; any path returned | |
410 | * is relative to wherever sysfs is mounted. | |
411 | * | |
412 | * XXX: does no error checking on @path size | |
413 | */ | |
414 | static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) | |
415 | { | |
416 | if (sd->s_parent) { | |
417 | sysfs_pathname(sd->s_parent, path); | |
418 | strcat(path, "/"); | |
419 | } | |
420 | strcat(path, sd->s_name); | |
421 | return path; | |
422 | } | |
423 | ||
36ce6dad CH |
424 | /** |
425 | * sysfs_add_one - add sysfs_dirent to parent | |
426 | * @acxt: addrm context to use | |
427 | * @sd: sysfs_dirent to be added | |
428 | * | |
429 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
430 | * nlink of parent inode if @sd is a directory and link into the | |
431 | * children list of the parent. | |
432 | * | |
433 | * This function should be called between calls to | |
434 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
435 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
436 | * | |
437 | * LOCKING: | |
438 | * Determined by sysfs_addrm_start(). | |
439 | * | |
440 | * RETURNS: | |
441 | * 0 on success, -EEXIST if entry with the given name already | |
442 | * exists. | |
443 | */ | |
444 | int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
445 | { | |
446 | int ret; | |
447 | ||
448 | ret = __sysfs_add_one(acxt, sd); | |
425cb029 AC |
449 | if (ret == -EEXIST) { |
450 | char *path = kzalloc(PATH_MAX, GFP_KERNEL); | |
451 | WARN(1, KERN_WARNING | |
452 | "sysfs: cannot create duplicate filename '%s'\n", | |
453 | (path == NULL) ? sd->s_name : | |
454 | strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"), | |
455 | sd->s_name)); | |
456 | kfree(path); | |
457 | } | |
458 | ||
36ce6dad CH |
459 | return ret; |
460 | } | |
461 | ||
fb6896da TH |
462 | /** |
463 | * sysfs_remove_one - remove sysfs_dirent from parent | |
464 | * @acxt: addrm context to use | |
9fd5b1c9 | 465 | * @sd: sysfs_dirent to be removed |
fb6896da TH |
466 | * |
467 | * Mark @sd removed and drop nlink of parent inode if @sd is a | |
181b2e4b | 468 | * directory. @sd is unlinked from the children list. |
fb6896da TH |
469 | * |
470 | * This function should be called between calls to | |
471 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
472 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
473 | * | |
474 | * LOCKING: | |
475 | * Determined by sysfs_addrm_start(). | |
476 | */ | |
477 | void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
478 | { | |
6b0bfe93 EB |
479 | struct sysfs_inode_attrs *ps_iattr; |
480 | ||
41fc1c27 TH |
481 | BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED); |
482 | ||
483 | sysfs_unlink_sibling(sd); | |
fb6896da | 484 | |
6b0bfe93 EB |
485 | /* Update timestamps on the parent */ |
486 | ps_iattr = acxt->parent_sd->s_iattr; | |
487 | if (ps_iattr) { | |
488 | struct iattr *ps_iattrs = &ps_iattr->ia_iattr; | |
489 | ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; | |
490 | } | |
491 | ||
fb6896da TH |
492 | sd->s_flags |= SYSFS_FLAG_REMOVED; |
493 | sd->s_sibling = acxt->removed; | |
494 | acxt->removed = sd; | |
a0edd7c8 TH |
495 | } |
496 | ||
fb6896da TH |
497 | /** |
498 | * sysfs_addrm_finish - finish up sysfs_dirent add/remove | |
499 | * @acxt: addrm context to finish up | |
500 | * | |
501 | * Finish up sysfs_dirent add/remove. Resources acquired by | |
502 | * sysfs_addrm_start() are released and removed sysfs_dirents are | |
a16bbc34 | 503 | * cleaned up. |
fb6896da TH |
504 | * |
505 | * LOCKING: | |
a16bbc34 | 506 | * sysfs_mutex is released. |
fb6896da | 507 | */ |
990e53f8 | 508 | void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) |
fb6896da TH |
509 | { |
510 | /* release resources acquired by sysfs_addrm_start() */ | |
511 | mutex_unlock(&sysfs_mutex); | |
fb6896da TH |
512 | |
513 | /* kill removed sysfs_dirents */ | |
514 | while (acxt->removed) { | |
515 | struct sysfs_dirent *sd = acxt->removed; | |
516 | ||
517 | acxt->removed = sd->s_sibling; | |
518 | sd->s_sibling = NULL; | |
519 | ||
fb6896da | 520 | sysfs_deactivate(sd); |
e0edd3c6 | 521 | unmap_bin_file(sd); |
fb6896da | 522 | sysfs_put(sd); |
13b3086d | 523 | } |
b592fcfe EB |
524 | } |
525 | ||
f0b0af47 TH |
526 | /** |
527 | * sysfs_find_dirent - find sysfs_dirent with the given name | |
528 | * @parent_sd: sysfs_dirent to search under | |
529 | * @name: name to look for | |
530 | * | |
531 | * Look for sysfs_dirent with name @name under @parent_sd. | |
c516865c | 532 | * |
f0b0af47 | 533 | * LOCKING: |
3007e997 | 534 | * mutex_lock(sysfs_mutex) |
c516865c | 535 | * |
f0b0af47 TH |
536 | * RETURNS: |
537 | * Pointer to sysfs_dirent if found, NULL if not. | |
c516865c | 538 | */ |
f0b0af47 | 539 | struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, |
3ff195b0 | 540 | const void *ns, |
f0b0af47 | 541 | const unsigned char *name) |
c516865c | 542 | { |
f0b0af47 TH |
543 | struct sysfs_dirent *sd; |
544 | ||
3ff195b0 | 545 | for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) { |
af10ec77 | 546 | if (ns && sd->s_ns && (sd->s_ns != ns)) |
3ff195b0 | 547 | continue; |
3efa65b9 | 548 | if (!strcmp(sd->s_name, name)) |
f0b0af47 | 549 | return sd; |
3ff195b0 | 550 | } |
f0b0af47 TH |
551 | return NULL; |
552 | } | |
c516865c | 553 | |
f0b0af47 TH |
554 | /** |
555 | * sysfs_get_dirent - find and get sysfs_dirent with the given name | |
556 | * @parent_sd: sysfs_dirent to search under | |
557 | * @name: name to look for | |
558 | * | |
559 | * Look for sysfs_dirent with name @name under @parent_sd and get | |
560 | * it if found. | |
561 | * | |
562 | * LOCKING: | |
3007e997 | 563 | * Kernel thread context (may sleep). Grabs sysfs_mutex. |
f0b0af47 TH |
564 | * |
565 | * RETURNS: | |
566 | * Pointer to sysfs_dirent if found, NULL if not. | |
567 | */ | |
568 | struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, | |
3ff195b0 | 569 | const void *ns, |
f0b0af47 TH |
570 | const unsigned char *name) |
571 | { | |
572 | struct sysfs_dirent *sd; | |
573 | ||
3007e997 | 574 | mutex_lock(&sysfs_mutex); |
3ff195b0 | 575 | sd = sysfs_find_dirent(parent_sd, ns, name); |
f0b0af47 | 576 | sysfs_get(sd); |
3007e997 | 577 | mutex_unlock(&sysfs_mutex); |
f0b0af47 TH |
578 | |
579 | return sd; | |
c516865c | 580 | } |
f1282c84 | 581 | EXPORT_SYMBOL_GPL(sysfs_get_dirent); |
c516865c | 582 | |
608e266a | 583 | static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
3ff195b0 EB |
584 | enum kobj_ns_type type, const void *ns, const char *name, |
585 | struct sysfs_dirent **p_sd) | |
1da177e4 | 586 | { |
1da177e4 | 587 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
51225039 | 588 | struct sysfs_addrm_cxt acxt; |
dfeb9fb0 | 589 | struct sysfs_dirent *sd; |
23dc2799 | 590 | int rc; |
1da177e4 | 591 | |
fc9f54b9 | 592 | /* allocate */ |
3e519038 | 593 | sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
a26cd722 | 594 | if (!sd) |
51225039 | 595 | return -ENOMEM; |
3ff195b0 EB |
596 | |
597 | sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT); | |
598 | sd->s_ns = ns; | |
b1fc3d61 | 599 | sd->s_dir.kobj = kobj; |
dfeb9fb0 | 600 | |
fc9f54b9 | 601 | /* link in */ |
51225039 | 602 | sysfs_addrm_start(&acxt, parent_sd); |
23dc2799 TH |
603 | rc = sysfs_add_one(&acxt, sd); |
604 | sysfs_addrm_finish(&acxt); | |
967e35dc | 605 | |
23dc2799 TH |
606 | if (rc == 0) |
607 | *p_sd = sd; | |
608 | else | |
967e35dc | 609 | sysfs_put(sd); |
dfeb9fb0 | 610 | |
23dc2799 | 611 | return rc; |
1da177e4 LT |
612 | } |
613 | ||
608e266a TH |
614 | int sysfs_create_subdir(struct kobject *kobj, const char *name, |
615 | struct sysfs_dirent **p_sd) | |
1da177e4 | 616 | { |
3ff195b0 EB |
617 | return create_dir(kobj, kobj->sd, |
618 | KOBJ_NS_TYPE_NONE, NULL, name, p_sd); | |
619 | } | |
620 | ||
be867b19 SH |
621 | /** |
622 | * sysfs_read_ns_type: return associated ns_type | |
623 | * @kobj: the kobject being queried | |
624 | * | |
625 | * Each kobject can be tagged with exactly one namespace type | |
626 | * (i.e. network or user). Return the ns_type associated with | |
627 | * this object if any | |
628 | */ | |
3ff195b0 EB |
629 | static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj) |
630 | { | |
631 | const struct kobj_ns_type_operations *ops; | |
632 | enum kobj_ns_type type; | |
633 | ||
634 | ops = kobj_child_ns_ops(kobj); | |
635 | if (!ops) | |
636 | return KOBJ_NS_TYPE_NONE; | |
637 | ||
638 | type = ops->type; | |
639 | BUG_ON(type <= KOBJ_NS_TYPE_NONE); | |
640 | BUG_ON(type >= KOBJ_NS_TYPES); | |
641 | BUG_ON(!kobj_ns_type_registered(type)); | |
642 | ||
643 | return type; | |
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 | { |
3ff195b0 | 652 | enum kobj_ns_type type; |
608e266a | 653 | struct sysfs_dirent *parent_sd, *sd; |
3ff195b0 | 654 | const void *ns = NULL; |
1da177e4 LT |
655 | int error = 0; |
656 | ||
657 | BUG_ON(!kobj); | |
658 | ||
90bc6135 | 659 | if (kobj->parent) |
608e266a | 660 | parent_sd = kobj->parent->sd; |
1da177e4 | 661 | else |
7d0c7d67 | 662 | parent_sd = &sysfs_root; |
1da177e4 | 663 | |
3ff195b0 EB |
664 | if (sysfs_ns_type(parent_sd)) |
665 | ns = kobj->ktype->namespace(kobj); | |
666 | type = sysfs_read_ns_type(kobj); | |
667 | ||
668 | error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd); | |
1da177e4 | 669 | if (!error) |
608e266a | 670 | kobj->sd = sd; |
1da177e4 LT |
671 | return error; |
672 | } | |
673 | ||
1da177e4 LT |
674 | static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
675 | struct nameidata *nd) | |
676 | { | |
6cb52147 | 677 | struct dentry *ret = NULL; |
3ff195b0 EB |
678 | struct dentry *parent = dentry->d_parent; |
679 | struct sysfs_dirent *parent_sd = parent->d_fsdata; | |
a7a04754 | 680 | struct sysfs_dirent *sd; |
fc9f54b9 | 681 | struct inode *inode; |
3ff195b0 EB |
682 | enum kobj_ns_type type; |
683 | const void *ns; | |
1da177e4 | 684 | |
6cb52147 TH |
685 | mutex_lock(&sysfs_mutex); |
686 | ||
3ff195b0 EB |
687 | type = sysfs_ns_type(parent_sd); |
688 | ns = sysfs_info(dir->i_sb)->ns[type]; | |
689 | ||
690 | sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name); | |
1da177e4 | 691 | |
fc9f54b9 | 692 | /* no such entry */ |
e49452c6 TH |
693 | if (!sd) { |
694 | ret = ERR_PTR(-ENOENT); | |
6cb52147 | 695 | goto out_unlock; |
e49452c6 | 696 | } |
fc9f54b9 TH |
697 | |
698 | /* attach dentry and inode */ | |
fac2622b | 699 | inode = sysfs_get_inode(dir->i_sb, sd); |
6cb52147 TH |
700 | if (!inode) { |
701 | ret = ERR_PTR(-ENOMEM); | |
702 | goto out_unlock; | |
703 | } | |
3007e997 | 704 | |
d6b4fd2f | 705 | /* instantiate and hash dentry */ |
832b6af1 EB |
706 | ret = d_find_alias(inode); |
707 | if (!ret) { | |
fb045adb | 708 | d_set_d_op(dentry, &sysfs_dentry_ops); |
832b6af1 EB |
709 | dentry->d_fsdata = sysfs_get(sd); |
710 | d_add(dentry, inode); | |
711 | } else { | |
712 | d_move(ret, dentry); | |
713 | iput(inode); | |
714 | } | |
fc9f54b9 | 715 | |
6cb52147 | 716 | out_unlock: |
3007e997 | 717 | mutex_unlock(&sysfs_mutex); |
6cb52147 | 718 | return ret; |
1da177e4 LT |
719 | } |
720 | ||
c5ef1c42 | 721 | const struct inode_operations sysfs_dir_inode_operations = { |
1da177e4 | 722 | .lookup = sysfs_lookup, |
e61ab4ae | 723 | .permission = sysfs_permission, |
988d186d | 724 | .setattr = sysfs_setattr, |
e61ab4ae | 725 | .getattr = sysfs_getattr, |
ddd29ec6 | 726 | .setxattr = sysfs_setxattr, |
1da177e4 LT |
727 | }; |
728 | ||
608e266a | 729 | static void remove_dir(struct sysfs_dirent *sd) |
1da177e4 | 730 | { |
fb6896da | 731 | struct sysfs_addrm_cxt acxt; |
1da177e4 | 732 | |
fb6896da | 733 | sysfs_addrm_start(&acxt, sd->s_parent); |
fb6896da TH |
734 | sysfs_remove_one(&acxt, sd); |
735 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
736 | } |
737 | ||
608e266a | 738 | void sysfs_remove_subdir(struct sysfs_dirent *sd) |
1da177e4 | 739 | { |
608e266a | 740 | remove_dir(sd); |
1da177e4 LT |
741 | } |
742 | ||
743 | ||
608e266a | 744 | static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
1da177e4 | 745 | { |
fb6896da | 746 | struct sysfs_addrm_cxt acxt; |
0c73f18b | 747 | struct sysfs_dirent **pos; |
1da177e4 | 748 | |
608e266a | 749 | if (!dir_sd) |
1da177e4 LT |
750 | return; |
751 | ||
608e266a | 752 | pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
fb6896da | 753 | sysfs_addrm_start(&acxt, dir_sd); |
bc747f37 | 754 | pos = &dir_sd->s_dir.children; |
0c73f18b TH |
755 | while (*pos) { |
756 | struct sysfs_dirent *sd = *pos; | |
757 | ||
3efa65b9 | 758 | if (sysfs_type(sd) != SYSFS_DIR) |
fb6896da | 759 | sysfs_remove_one(&acxt, sd); |
41fc1c27 | 760 | else |
0c73f18b | 761 | pos = &(*pos)->s_sibling; |
1da177e4 | 762 | } |
fb6896da | 763 | sysfs_addrm_finish(&acxt); |
0ab66088 | 764 | |
608e266a | 765 | remove_dir(dir_sd); |
b592fcfe EB |
766 | } |
767 | ||
768 | /** | |
769 | * sysfs_remove_dir - remove an object's directory. | |
770 | * @kobj: object. | |
771 | * | |
772 | * The only thing special about this is that we remove any files in | |
773 | * the directory before we remove the directory, and we've inlined | |
774 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
775 | */ | |
776 | ||
777 | void sysfs_remove_dir(struct kobject * kobj) | |
778 | { | |
608e266a | 779 | struct sysfs_dirent *sd = kobj->sd; |
aecdceda | 780 | |
5f995323 | 781 | spin_lock(&sysfs_assoc_lock); |
608e266a | 782 | kobj->sd = NULL; |
5f995323 | 783 | spin_unlock(&sysfs_assoc_lock); |
aecdceda | 784 | |
608e266a | 785 | __sysfs_remove_dir(sd); |
1da177e4 LT |
786 | } |
787 | ||
ca1bab38 | 788 | int sysfs_rename(struct sysfs_dirent *sd, |
3ff195b0 EB |
789 | struct sysfs_dirent *new_parent_sd, const void *new_ns, |
790 | const char *new_name) | |
1da177e4 | 791 | { |
51225039 | 792 | const char *dup_name = NULL; |
996b7376 | 793 | int error; |
1da177e4 | 794 | |
832b6af1 | 795 | mutex_lock(&sysfs_mutex); |
932ea2e3 | 796 | |
9918f9a4 | 797 | error = 0; |
3ff195b0 | 798 | if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) && |
ca1bab38 | 799 | (strcmp(sd->s_name, new_name) == 0)) |
9918f9a4 EB |
800 | goto out; /* nothing to rename */ |
801 | ||
9918f9a4 | 802 | error = -EEXIST; |
3ff195b0 | 803 | if (sysfs_find_dirent(new_parent_sd, new_ns, new_name)) |
832b6af1 | 804 | goto out; |
996b7376 | 805 | |
0b4a4fea | 806 | /* rename sysfs_dirent */ |
ca1bab38 EB |
807 | if (strcmp(sd->s_name, new_name) != 0) { |
808 | error = -ENOMEM; | |
809 | new_name = dup_name = kstrdup(new_name, GFP_KERNEL); | |
810 | if (!new_name) | |
811 | goto out; | |
812 | ||
813 | dup_name = sd->s_name; | |
814 | sd->s_name = new_name; | |
815 | } | |
0c096b50 | 816 | |
ca1bab38 EB |
817 | /* Remove from old parent's list and insert into new parent's list. */ |
818 | if (sd->s_parent != new_parent_sd) { | |
819 | sysfs_unlink_sibling(sd); | |
820 | sysfs_get(new_parent_sd); | |
821 | sysfs_put(sd->s_parent); | |
822 | sd->s_parent = new_parent_sd; | |
823 | sysfs_link_sibling(sd); | |
824 | } | |
3ff195b0 | 825 | sd->s_ns = new_ns; |
0c096b50 | 826 | |
996b7376 | 827 | error = 0; |
832b6af1 | 828 | out: |
9918f9a4 | 829 | mutex_unlock(&sysfs_mutex); |
51225039 | 830 | kfree(dup_name); |
1da177e4 LT |
831 | return error; |
832 | } | |
833 | ||
ca1bab38 EB |
834 | int sysfs_rename_dir(struct kobject *kobj, const char *new_name) |
835 | { | |
3ff195b0 EB |
836 | struct sysfs_dirent *parent_sd = kobj->sd->s_parent; |
837 | const void *new_ns = NULL; | |
838 | ||
839 | if (sysfs_ns_type(parent_sd)) | |
840 | new_ns = kobj->ktype->namespace(kobj); | |
841 | ||
842 | return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name); | |
ca1bab38 EB |
843 | } |
844 | ||
51225039 | 845 | int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) |
8a82472f | 846 | { |
51225039 TH |
847 | struct sysfs_dirent *sd = kobj->sd; |
848 | struct sysfs_dirent *new_parent_sd; | |
3ff195b0 | 849 | const void *new_ns = NULL; |
8a82472f | 850 | |
51225039 | 851 | BUG_ON(!sd->s_parent); |
3ff195b0 EB |
852 | if (sysfs_ns_type(sd->s_parent)) |
853 | new_ns = kobj->ktype->namespace(kobj); | |
ca1bab38 | 854 | new_parent_sd = new_parent_kobj && new_parent_kobj->sd ? |
a6a83577 | 855 | new_parent_kobj->sd : &sysfs_root; |
51225039 | 856 | |
3ff195b0 | 857 | return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name); |
8a82472f CH |
858 | } |
859 | ||
1da177e4 LT |
860 | /* Relationship between s_mode and the DT_xxx types */ |
861 | static inline unsigned char dt_type(struct sysfs_dirent *sd) | |
862 | { | |
863 | return (sd->s_mode >> 12) & 15; | |
864 | } | |
865 | ||
1e5289c9 EB |
866 | static int sysfs_dir_release(struct inode *inode, struct file *filp) |
867 | { | |
868 | sysfs_put(filp->private_data); | |
869 | return 0; | |
870 | } | |
871 | ||
3ff195b0 EB |
872 | static struct sysfs_dirent *sysfs_dir_pos(const void *ns, |
873 | struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos) | |
1e5289c9 EB |
874 | { |
875 | if (pos) { | |
876 | int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) && | |
877 | pos->s_parent == parent_sd && | |
878 | ino == pos->s_ino; | |
879 | sysfs_put(pos); | |
3ff195b0 EB |
880 | if (!valid) |
881 | pos = NULL; | |
1e5289c9 | 882 | } |
3ff195b0 | 883 | if (!pos && (ino > 1) && (ino < INT_MAX)) { |
1e5289c9 EB |
884 | pos = parent_sd->s_dir.children; |
885 | while (pos && (ino > pos->s_ino)) | |
886 | pos = pos->s_sibling; | |
887 | } | |
af10ec77 | 888 | while (pos && pos->s_ns && pos->s_ns != ns) |
3ff195b0 | 889 | pos = pos->s_sibling; |
1e5289c9 EB |
890 | return pos; |
891 | } | |
892 | ||
3ff195b0 EB |
893 | static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns, |
894 | struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos) | |
1e5289c9 | 895 | { |
3ff195b0 | 896 | pos = sysfs_dir_pos(ns, parent_sd, ino, pos); |
1e5289c9 EB |
897 | if (pos) |
898 | pos = pos->s_sibling; | |
af10ec77 | 899 | while (pos && pos->s_ns && pos->s_ns != ns) |
3ff195b0 | 900 | pos = pos->s_sibling; |
1e5289c9 EB |
901 | return pos; |
902 | } | |
903 | ||
1da177e4 LT |
904 | static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) |
905 | { | |
f427f5d5 | 906 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 907 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
1e5289c9 | 908 | struct sysfs_dirent *pos = filp->private_data; |
3ff195b0 EB |
909 | enum kobj_ns_type type; |
910 | const void *ns; | |
1da177e4 | 911 | ino_t ino; |
1da177e4 | 912 | |
3ff195b0 EB |
913 | type = sysfs_ns_type(parent_sd); |
914 | ns = sysfs_info(dentry->d_sb)->ns[type]; | |
915 | ||
3efa65b9 EB |
916 | if (filp->f_pos == 0) { |
917 | ino = parent_sd->s_ino; | |
918 | if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 919 | filp->f_pos++; |
3efa65b9 EB |
920 | } |
921 | if (filp->f_pos == 1) { | |
922 | if (parent_sd->s_parent) | |
923 | ino = parent_sd->s_parent->s_ino; | |
924 | else | |
925 | ino = parent_sd->s_ino; | |
926 | if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 927 | filp->f_pos++; |
3efa65b9 | 928 | } |
1e5289c9 | 929 | mutex_lock(&sysfs_mutex); |
3ff195b0 | 930 | for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos); |
1e5289c9 | 931 | pos; |
3ff195b0 | 932 | pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) { |
1e5289c9 EB |
933 | const char * name; |
934 | unsigned int type; | |
935 | int len, ret; | |
936 | ||
937 | name = pos->s_name; | |
938 | len = strlen(name); | |
939 | ino = pos->s_ino; | |
940 | type = dt_type(pos); | |
941 | filp->f_pos = ino; | |
942 | filp->private_data = sysfs_get(pos); | |
1da177e4 | 943 | |
3007e997 | 944 | mutex_unlock(&sysfs_mutex); |
1e5289c9 EB |
945 | ret = filldir(dirent, name, len, filp->f_pos, ino, type); |
946 | mutex_lock(&sysfs_mutex); | |
947 | if (ret < 0) | |
948 | break; | |
949 | } | |
950 | mutex_unlock(&sysfs_mutex); | |
951 | if ((filp->f_pos > 1) && !pos) { /* EOF */ | |
952 | filp->f_pos = INT_MAX; | |
953 | filp->private_data = NULL; | |
1da177e4 | 954 | } |
3efa65b9 | 955 | return 0; |
1da177e4 LT |
956 | } |
957 | ||
3efa65b9 | 958 | |
4b6f5d20 | 959 | const struct file_operations sysfs_dir_operations = { |
1da177e4 LT |
960 | .read = generic_read_dir, |
961 | .readdir = sysfs_readdir, | |
1e5289c9 | 962 | .release = sysfs_dir_release, |
3222a3e5 | 963 | .llseek = generic_file_llseek, |
1da177e4 | 964 | }; |