Commit | Line | Data |
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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
fa60ce2c | 2 | /* |
7063fbf2 JB |
3 | * dir.c - Operations for configfs directories. |
4 | * | |
7063fbf2 JB |
5 | * Based on sysfs: |
6 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
7 | * | |
8 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
9 | */ | |
10 | ||
11 | #undef DEBUG | |
12 | ||
13 | #include <linux/fs.h> | |
6146e78c | 14 | #include <linux/fsnotify.h> |
7063fbf2 JB |
15 | #include <linux/mount.h> |
16 | #include <linux/module.h> | |
17 | #include <linux/slab.h> | |
107ed40b | 18 | #include <linux/err.h> |
7063fbf2 JB |
19 | |
20 | #include <linux/configfs.h> | |
21 | #include "configfs_internal.h" | |
22 | ||
6f610764 LR |
23 | /* |
24 | * Protects mutations of configfs_dirent linkage together with proper i_mutex | |
5301a77d | 25 | * Also protects mutations of symlinks linkage to target configfs_dirent |
6f610764 LR |
26 | * Mutators of configfs_dirent linkage must *both* have the proper inode locked |
27 | * and configfs_dirent_lock locked, in that order. | |
5301a77d LR |
28 | * This allows one to safely traverse configfs_dirent trees and symlinks without |
29 | * having to lock inodes. | |
b3e76af8 LR |
30 | * |
31 | * Protects setting of CONFIGFS_USET_DROPPING: checking the flag | |
32 | * unlocked is not reliable unless in detach_groups() called from | |
33 | * rmdir()/unregister() and from configfs_attach_group() | |
6f610764 LR |
34 | */ |
35 | DEFINE_SPINLOCK(configfs_dirent_lock); | |
7063fbf2 JB |
36 | |
37 | static void configfs_d_iput(struct dentry * dentry, | |
38 | struct inode * inode) | |
39 | { | |
24307aa1 | 40 | struct configfs_dirent *sd = dentry->d_fsdata; |
7063fbf2 JB |
41 | |
42 | if (sd) { | |
24307aa1 JB |
43 | /* Coordinate with configfs_readdir */ |
44 | spin_lock(&configfs_dirent_lock); | |
f6122ed2 ST |
45 | /* |
46 | * Set sd->s_dentry to null only when this dentry is the one | |
47 | * that is going to be killed. Otherwise configfs_d_iput may | |
48 | * run just after configfs_attach_attr and set sd->s_dentry to | |
49 | * NULL even it's still in use. | |
76ae281f | 50 | */ |
f6122ed2 | 51 | if (sd->s_dentry == dentry) |
76ae281f JB |
52 | sd->s_dentry = NULL; |
53 | ||
24307aa1 | 54 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
55 | configfs_put(sd); |
56 | } | |
57 | iput(inode); | |
58 | } | |
59 | ||
d463a0c4 | 60 | const struct dentry_operations configfs_dentry_ops = { |
7063fbf2 | 61 | .d_iput = configfs_d_iput, |
b26d4cd3 | 62 | .d_delete = always_delete_dentry, |
7063fbf2 JB |
63 | }; |
64 | ||
e74cc06d LR |
65 | #ifdef CONFIG_LOCKDEP |
66 | ||
67 | /* | |
68 | * Helpers to make lockdep happy with our recursive locking of default groups' | |
69 | * inodes (see configfs_attach_group() and configfs_detach_group()). | |
70 | * We put default groups i_mutexes in separate classes according to their depth | |
71 | * from the youngest non-default group ancestor. | |
72 | * | |
73 | * For a non-default group A having default groups A/B, A/C, and A/C/D, default | |
74 | * groups A/B and A/C will have their inode's mutex in class | |
75 | * default_group_class[0], and default group A/C/D will be in | |
76 | * default_group_class[1]. | |
77 | * | |
78 | * The lock classes are declared and assigned in inode.c, according to the | |
79 | * s_depth value. | |
80 | * The s_depth value is initialized to -1, adjusted to >= 0 when attaching | |
81 | * default groups, and reset to -1 when all default groups are attached. During | |
82 | * attachment, if configfs_create() sees s_depth > 0, the lock class of the new | |
83 | * inode's mutex is set to default_group_class[s_depth - 1]. | |
84 | */ | |
85 | ||
86 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
87 | { | |
88 | sd->s_depth = -1; | |
89 | } | |
90 | ||
91 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
92 | struct configfs_dirent *sd) | |
93 | { | |
94 | int parent_depth = parent_sd->s_depth; | |
95 | ||
96 | if (parent_depth >= 0) | |
97 | sd->s_depth = parent_depth + 1; | |
98 | } | |
99 | ||
100 | static void | |
101 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
102 | { | |
103 | /* | |
104 | * item's i_mutex class is already setup, so s_depth is now only | |
105 | * used to set new sub-directories s_depth, which is always done | |
106 | * with item's i_mutex locked. | |
107 | */ | |
108 | /* | |
109 | * sd->s_depth == -1 iff we are a non default group. | |
110 | * else (we are a default group) sd->s_depth > 0 (see | |
111 | * create_dir()). | |
112 | */ | |
113 | if (sd->s_depth == -1) | |
114 | /* | |
115 | * We are a non default group and we are going to create | |
116 | * default groups. | |
117 | */ | |
118 | sd->s_depth = 0; | |
119 | } | |
120 | ||
121 | static void | |
122 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
123 | { | |
124 | /* We will not create default groups anymore. */ | |
125 | sd->s_depth = -1; | |
126 | } | |
127 | ||
128 | #else /* CONFIG_LOCKDEP */ | |
129 | ||
130 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
131 | { | |
132 | } | |
133 | ||
134 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
135 | struct configfs_dirent *sd) | |
136 | { | |
137 | } | |
138 | ||
139 | static void | |
140 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
141 | { | |
142 | } | |
143 | ||
144 | static void | |
145 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
146 | { | |
147 | } | |
148 | ||
149 | #endif /* CONFIG_LOCKDEP */ | |
150 | ||
47320fbe AV |
151 | static struct configfs_fragment *new_fragment(void) |
152 | { | |
153 | struct configfs_fragment *p; | |
154 | ||
155 | p = kmalloc(sizeof(struct configfs_fragment), GFP_KERNEL); | |
156 | if (p) { | |
157 | atomic_set(&p->frag_count, 1); | |
158 | init_rwsem(&p->frag_sem); | |
159 | p->frag_dead = false; | |
160 | } | |
161 | return p; | |
162 | } | |
163 | ||
164 | void put_fragment(struct configfs_fragment *frag) | |
165 | { | |
166 | if (frag && atomic_dec_and_test(&frag->frag_count)) | |
167 | kfree(frag); | |
168 | } | |
169 | ||
170 | struct configfs_fragment *get_fragment(struct configfs_fragment *frag) | |
171 | { | |
172 | if (likely(frag)) | |
173 | atomic_inc(&frag->frag_count); | |
174 | return frag; | |
175 | } | |
176 | ||
7063fbf2 JB |
177 | /* |
178 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
179 | */ | |
420118ca | 180 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
47320fbe AV |
181 | void *element, int type, |
182 | struct configfs_fragment *frag) | |
7063fbf2 JB |
183 | { |
184 | struct configfs_dirent * sd; | |
185 | ||
c3762229 | 186 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 187 | if (!sd) |
107ed40b | 188 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 189 | |
7063fbf2 | 190 | atomic_set(&sd->s_count, 1); |
7063fbf2 | 191 | INIT_LIST_HEAD(&sd->s_children); |
7063fbf2 | 192 | sd->s_element = element; |
420118ca | 193 | sd->s_type = type; |
e74cc06d | 194 | configfs_init_dirent_depth(sd); |
6f610764 | 195 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
196 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
197 | spin_unlock(&configfs_dirent_lock); | |
198 | kmem_cache_free(configfs_dir_cachep, sd); | |
199 | return ERR_PTR(-ENOENT); | |
200 | } | |
47320fbe | 201 | sd->s_frag = get_fragment(frag); |
6f610764 LR |
202 | list_add(&sd->s_sibling, &parent_sd->s_children); |
203 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
204 | |
205 | return sd; | |
206 | } | |
207 | ||
b4c98f62 JB |
208 | /* |
209 | * | |
210 | * Return -EEXIST if there is already a configfs element with the same | |
211 | * name for the same parent. | |
212 | * | |
213 | * called with parent inode's i_mutex held | |
214 | */ | |
58d206c2 AB |
215 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
216 | const unsigned char *new) | |
b4c98f62 JB |
217 | { |
218 | struct configfs_dirent * sd; | |
219 | ||
220 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
221 | if (sd->s_element) { | |
222 | const unsigned char *existing = configfs_get_name(sd); | |
223 | if (strcmp(existing, new)) | |
224 | continue; | |
225 | else | |
226 | return -EEXIST; | |
227 | } | |
228 | } | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | ||
7063fbf2 JB |
234 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
235 | struct dentry * dentry, void * element, | |
47320fbe | 236 | umode_t mode, int type, struct configfs_fragment *frag) |
7063fbf2 JB |
237 | { |
238 | struct configfs_dirent * sd; | |
239 | ||
47320fbe | 240 | sd = configfs_new_dirent(parent_sd, element, type, frag); |
107ed40b LR |
241 | if (IS_ERR(sd)) |
242 | return PTR_ERR(sd); | |
7063fbf2 JB |
243 | |
244 | sd->s_mode = mode; | |
7063fbf2 | 245 | sd->s_dentry = dentry; |
fbc8d4c0 | 246 | if (dentry) |
7063fbf2 | 247 | dentry->d_fsdata = configfs_get(sd); |
7063fbf2 JB |
248 | |
249 | return 0; | |
250 | } | |
251 | ||
1cf7a003 CH |
252 | static void configfs_remove_dirent(struct dentry *dentry) |
253 | { | |
254 | struct configfs_dirent *sd = dentry->d_fsdata; | |
255 | ||
256 | if (!sd) | |
257 | return; | |
258 | spin_lock(&configfs_dirent_lock); | |
259 | list_del_init(&sd->s_sibling); | |
260 | spin_unlock(&configfs_dirent_lock); | |
261 | configfs_put(sd); | |
262 | } | |
263 | ||
7063fbf2 JB |
264 | /** |
265 | * configfs_create_dir - create a directory for an config_item. | |
266 | * @item: config_itemwe're creating directory for. | |
267 | * @dentry: config_item's dentry. | |
65cdb4a2 | 268 | * @frag: config_item's fragment. |
2a109f2a LR |
269 | * |
270 | * Note: user-created entries won't be allowed under this new directory | |
271 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
272 | */ |
273 | ||
47320fbe AV |
274 | static int configfs_create_dir(struct config_item *item, struct dentry *dentry, |
275 | struct configfs_fragment *frag) | |
7063fbf2 | 276 | { |
1cf97d0d AV |
277 | int error; |
278 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
279 | struct dentry *p = dentry->d_parent; | |
2743c515 | 280 | struct inode *inode; |
1cf97d0d AV |
281 | |
282 | BUG_ON(!item); | |
283 | ||
284 | error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name); | |
285 | if (unlikely(error)) | |
286 | return error; | |
287 | ||
288 | error = configfs_make_dirent(p->d_fsdata, dentry, item, mode, | |
47320fbe AV |
289 | CONFIGFS_DIR | CONFIGFS_USET_CREATING, |
290 | frag); | |
1cf97d0d AV |
291 | if (unlikely(error)) |
292 | return error; | |
293 | ||
294 | configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata); | |
2743c515 AV |
295 | inode = configfs_create(dentry, mode); |
296 | if (IS_ERR(inode)) | |
1cf7a003 CH |
297 | goto out_remove; |
298 | ||
2743c515 AV |
299 | inode->i_op = &configfs_dir_inode_operations; |
300 | inode->i_fop = &configfs_dir_operations; | |
301 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
302 | inc_nlink(inode); | |
303 | d_instantiate(dentry, inode); | |
304 | /* already hashed */ | |
305 | dget(dentry); /* pin directory dentries in core */ | |
1cf7a003 CH |
306 | inc_nlink(d_inode(p)); |
307 | item->ci_dentry = dentry; | |
308 | return 0; | |
309 | ||
310 | out_remove: | |
311 | configfs_remove_dirent(dentry); | |
2743c515 | 312 | return PTR_ERR(inode); |
7063fbf2 JB |
313 | } |
314 | ||
2a109f2a LR |
315 | /* |
316 | * Allow userspace to create new entries under a new directory created with | |
317 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
318 | * @sd configfs_dirent of the new directory to validate | |
319 | * | |
320 | * Caller must hold configfs_dirent_lock. | |
321 | */ | |
322 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
323 | { | |
324 | struct configfs_dirent *child_sd; | |
325 | ||
326 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
327 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
328 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
329 | configfs_dir_set_ready(child_sd); | |
330 | } | |
331 | ||
332 | /* | |
333 | * Check that a directory does not belong to a directory hierarchy being | |
334 | * attached and not validated yet. | |
335 | * @sd configfs_dirent of the directory to check | |
336 | * | |
337 | * @return non-zero iff the directory was validated | |
338 | * | |
339 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
340 | * in two consecutive calls, but never from true to false. | |
341 | */ | |
342 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
343 | { | |
344 | int ret; | |
345 | ||
346 | spin_lock(&configfs_dirent_lock); | |
347 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
348 | spin_unlock(&configfs_dirent_lock); | |
349 | ||
350 | return ret; | |
351 | } | |
352 | ||
e9c03af2 AV |
353 | int configfs_create_link(struct configfs_dirent *target, struct dentry *parent, |
354 | struct dentry *dentry, char *body) | |
7063fbf2 JB |
355 | { |
356 | int err = 0; | |
357 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
47320fbe | 358 | struct configfs_dirent *p = parent->d_fsdata; |
2743c515 | 359 | struct inode *inode; |
7063fbf2 | 360 | |
e9c03af2 AV |
361 | err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK, |
362 | p->s_frag); | |
1cf7a003 CH |
363 | if (err) |
364 | return err; | |
365 | ||
2743c515 AV |
366 | inode = configfs_create(dentry, mode); |
367 | if (IS_ERR(inode)) | |
1cf7a003 | 368 | goto out_remove; |
2743c515 | 369 | |
e9c03af2 | 370 | inode->i_link = body; |
2743c515 AV |
371 | inode->i_op = &configfs_symlink_inode_operations; |
372 | d_instantiate(dentry, inode); | |
373 | dget(dentry); /* pin link dentries in core */ | |
1cf7a003 CH |
374 | return 0; |
375 | ||
376 | out_remove: | |
377 | configfs_remove_dirent(dentry); | |
2743c515 | 378 | return PTR_ERR(inode); |
7063fbf2 JB |
379 | } |
380 | ||
381 | static void remove_dir(struct dentry * d) | |
382 | { | |
383 | struct dentry * parent = dget(d->d_parent); | |
7063fbf2 | 384 | |
1cf7a003 CH |
385 | configfs_remove_dirent(d); |
386 | ||
2b0143b5 DH |
387 | if (d_really_is_positive(d)) |
388 | simple_rmdir(d_inode(parent),d); | |
7063fbf2 | 389 | |
a455589f | 390 | pr_debug(" o %pd removing done (%d)\n", d, d_count(d)); |
7063fbf2 JB |
391 | |
392 | dput(parent); | |
393 | } | |
394 | ||
395 | /** | |
396 | * configfs_remove_dir - remove an config_item's directory. | |
397 | * @item: config_item we're removing. | |
398 | * | |
399 | * The only thing special about this is that we remove any files in | |
400 | * the directory before we remove the directory, and we've inlined | |
401 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
402 | * |
403 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
404 | */ |
405 | ||
406 | static void configfs_remove_dir(struct config_item * item) | |
407 | { | |
408 | struct dentry * dentry = dget(item->ci_dentry); | |
409 | ||
410 | if (!dentry) | |
411 | return; | |
412 | ||
413 | remove_dir(dentry); | |
414 | /** | |
415 | * Drop reference from dget() on entrance. | |
416 | */ | |
417 | dput(dentry); | |
418 | } | |
419 | ||
420 | ||
421 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
422 | * attribute file | |
423 | */ | |
424 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
425 | { | |
426 | struct configfs_attribute * attr = sd->s_element; | |
2743c515 | 427 | struct inode *inode; |
7063fbf2 | 428 | |
76ae281f | 429 | spin_lock(&configfs_dirent_lock); |
3d0f89bb JB |
430 | dentry->d_fsdata = configfs_get(sd); |
431 | sd->s_dentry = dentry; | |
76ae281f JB |
432 | spin_unlock(&configfs_dirent_lock); |
433 | ||
2743c515 AV |
434 | inode = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG); |
435 | if (IS_ERR(inode)) { | |
3d0f89bb | 436 | configfs_put(sd); |
2743c515 AV |
437 | return PTR_ERR(inode); |
438 | } | |
439 | if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) { | |
440 | inode->i_size = 0; | |
441 | inode->i_fop = &configfs_bin_file_operations; | |
442 | } else { | |
443 | inode->i_size = PAGE_SIZE; | |
444 | inode->i_fop = &configfs_file_operations; | |
445 | } | |
446 | d_add(dentry, inode); | |
447 | return 0; | |
7063fbf2 JB |
448 | } |
449 | ||
450 | static struct dentry * configfs_lookup(struct inode *dir, | |
451 | struct dentry *dentry, | |
00cd8dd3 | 452 | unsigned int flags) |
7063fbf2 JB |
453 | { |
454 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
455 | struct configfs_dirent * sd; | |
456 | int found = 0; | |
2a109f2a LR |
457 | int err; |
458 | ||
417b962d CH |
459 | if (dentry->d_name.len > NAME_MAX) |
460 | return ERR_PTR(-ENAMETOOLONG); | |
461 | ||
2a109f2a LR |
462 | /* |
463 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
464 | * being attached | |
465 | * | |
466 | * This forbids userspace to read/write attributes of items which may | |
467 | * not complete their initialization, since the dentries of the | |
468 | * attributes won't be instantiated. | |
469 | */ | |
470 | err = -ENOENT; | |
471 | if (!configfs_dirent_is_ready(parent_sd)) | |
472 | goto out; | |
7063fbf2 JB |
473 | |
474 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
475 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
476 | const unsigned char * name = configfs_get_name(sd); | |
477 | ||
478 | if (strcmp(name, dentry->d_name.name)) | |
479 | continue; | |
480 | ||
481 | found = 1; | |
482 | err = configfs_attach_attr(sd, dentry); | |
483 | break; | |
484 | } | |
485 | } | |
486 | ||
487 | if (!found) { | |
488 | /* | |
489 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
490 | * it must be negative. | |
491 | */ | |
fbc8d4c0 NP |
492 | d_add(dentry, NULL); |
493 | return NULL; | |
7063fbf2 JB |
494 | } |
495 | ||
2a109f2a | 496 | out: |
7063fbf2 JB |
497 | return ERR_PTR(err); |
498 | } | |
499 | ||
500 | /* | |
501 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
502 | * attributes and are removed by rmdir(). We recurse, setting |
503 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
504 | * default detach. | |
505 | * If there is an error, the caller will reset the flags via | |
506 | * configfs_detach_rollback(). | |
7063fbf2 | 507 | */ |
48f35b7b | 508 | static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait) |
7063fbf2 JB |
509 | { |
510 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
511 | struct configfs_dirent *sd; | |
512 | int ret; | |
513 | ||
4768e9b1 LR |
514 | /* Mark that we're trying to drop the group */ |
515 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
516 | ||
7063fbf2 | 517 | ret = -EBUSY; |
e9c03af2 | 518 | if (parent_sd->s_links) |
7063fbf2 JB |
519 | goto out; |
520 | ||
521 | ret = 0; | |
522 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
523 | if (!sd->s_element || |
524 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
525 | continue; |
526 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
527 | /* Abort if racing with mkdir() */ |
528 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
48f35b7b AV |
529 | if (wait) |
530 | *wait= dget(sd->s_dentry); | |
6d8344ba LR |
531 | return -EAGAIN; |
532 | } | |
7063fbf2 | 533 | |
631d1feb JB |
534 | /* |
535 | * Yup, recursive. If there's a problem, blame | |
536 | * deep nesting of default_groups | |
537 | */ | |
48f35b7b | 538 | ret = configfs_detach_prep(sd->s_dentry, wait); |
7063fbf2 | 539 | if (!ret) |
e7515d06 | 540 | continue; |
7063fbf2 JB |
541 | } else |
542 | ret = -ENOTEMPTY; | |
543 | ||
544 | break; | |
545 | } | |
546 | ||
547 | out: | |
548 | return ret; | |
549 | } | |
550 | ||
551 | /* | |
b3e76af8 | 552 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
553 | * set. |
554 | */ | |
555 | static void configfs_detach_rollback(struct dentry *dentry) | |
556 | { | |
557 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
558 | struct configfs_dirent *sd; | |
559 | ||
4768e9b1 LR |
560 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
561 | ||
562 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
563 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 564 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
565 | } |
566 | ||
567 | static void detach_attrs(struct config_item * item) | |
568 | { | |
569 | struct dentry * dentry = dget(item->ci_dentry); | |
570 | struct configfs_dirent * parent_sd; | |
571 | struct configfs_dirent * sd, * tmp; | |
572 | ||
573 | if (!dentry) | |
574 | return; | |
575 | ||
576 | pr_debug("configfs %s: dropping attrs for dir\n", | |
577 | dentry->d_name.name); | |
578 | ||
579 | parent_sd = dentry->d_fsdata; | |
580 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
581 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
582 | continue; | |
6f610764 | 583 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 584 | list_del_init(&sd->s_sibling); |
6f610764 | 585 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
586 | configfs_drop_dentry(sd, dentry); |
587 | configfs_put(sd); | |
588 | } | |
589 | ||
590 | /** | |
591 | * Drop reference from dget() on entrance. | |
592 | */ | |
593 | dput(dentry); | |
594 | } | |
595 | ||
596 | static int populate_attrs(struct config_item *item) | |
597 | { | |
aa293583 | 598 | const struct config_item_type *t = item->ci_type; |
7063fbf2 | 599 | struct configfs_attribute *attr; |
03607ace | 600 | struct configfs_bin_attribute *bin_attr; |
7063fbf2 JB |
601 | int error = 0; |
602 | int i; | |
603 | ||
604 | if (!t) | |
605 | return -EINVAL; | |
606 | if (t->ct_attrs) { | |
607 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
608 | if ((error = configfs_create_file(item, attr))) | |
609 | break; | |
610 | } | |
611 | } | |
03607ace PA |
612 | if (t->ct_bin_attrs) { |
613 | for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) { | |
614 | error = configfs_create_bin_file(item, bin_attr); | |
615 | if (error) | |
616 | break; | |
617 | } | |
618 | } | |
7063fbf2 JB |
619 | |
620 | if (error) | |
621 | detach_attrs(item); | |
622 | ||
623 | return error; | |
624 | } | |
625 | ||
626 | static int configfs_attach_group(struct config_item *parent_item, | |
627 | struct config_item *item, | |
47320fbe AV |
628 | struct dentry *dentry, |
629 | struct configfs_fragment *frag); | |
7063fbf2 JB |
630 | static void configfs_detach_group(struct config_item *item); |
631 | ||
632 | static void detach_groups(struct config_group *group) | |
633 | { | |
634 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
635 | struct dentry *child; | |
636 | struct configfs_dirent *parent_sd; | |
637 | struct configfs_dirent *sd, *tmp; | |
638 | ||
639 | if (!dentry) | |
640 | return; | |
641 | ||
642 | parent_sd = dentry->d_fsdata; | |
643 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
644 | if (!sd->s_element || | |
645 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
646 | continue; | |
647 | ||
648 | child = sd->s_dentry; | |
649 | ||
5955102c | 650 | inode_lock(d_inode(child)); |
b3e76af8 | 651 | |
7063fbf2 | 652 | configfs_detach_group(sd->s_element); |
2b0143b5 | 653 | d_inode(child)->i_flags |= S_DEAD; |
d83c49f3 | 654 | dont_mount(child); |
7063fbf2 | 655 | |
5955102c | 656 | inode_unlock(d_inode(child)); |
7063fbf2 JB |
657 | |
658 | d_delete(child); | |
659 | dput(child); | |
660 | } | |
661 | ||
662 | /** | |
663 | * Drop reference from dget() on entrance. | |
664 | */ | |
665 | dput(dentry); | |
666 | } | |
667 | ||
668 | /* | |
669 | * This fakes mkdir(2) on a default_groups[] entry. It | |
670 | * creates a dentry, attachs it, and then does fixup | |
671 | * on the sd->s_type. | |
672 | * | |
673 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
674 | * try using vfs_mkdir. Just a thought. | |
675 | */ | |
676 | static int create_default_group(struct config_group *parent_group, | |
47320fbe AV |
677 | struct config_group *group, |
678 | struct configfs_fragment *frag) | |
7063fbf2 JB |
679 | { |
680 | int ret; | |
7063fbf2 JB |
681 | struct configfs_dirent *sd; |
682 | /* We trust the caller holds a reference to parent */ | |
683 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
684 | ||
685 | if (!group->cg_item.ci_name) | |
686 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
7063fbf2 JB |
687 | |
688 | ret = -ENOMEM; | |
ec193cf5 | 689 | child = d_alloc_name(parent, group->cg_item.ci_name); |
7063fbf2 JB |
690 | if (child) { |
691 | d_add(child, NULL); | |
692 | ||
693 | ret = configfs_attach_group(&parent_group->cg_item, | |
47320fbe | 694 | &group->cg_item, child, frag); |
7063fbf2 JB |
695 | if (!ret) { |
696 | sd = child->d_fsdata; | |
697 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
698 | } else { | |
2b0143b5 | 699 | BUG_ON(d_inode(child)); |
df7f9967 | 700 | d_drop(child); |
7063fbf2 JB |
701 | dput(child); |
702 | } | |
703 | } | |
704 | ||
705 | return ret; | |
706 | } | |
707 | ||
47320fbe AV |
708 | static int populate_groups(struct config_group *group, |
709 | struct configfs_fragment *frag) | |
7063fbf2 JB |
710 | { |
711 | struct config_group *new_group; | |
7063fbf2 | 712 | int ret = 0; |
7063fbf2 | 713 | |
1ae1602d | 714 | list_for_each_entry(new_group, &group->default_groups, group_entry) { |
47320fbe | 715 | ret = create_default_group(group, new_group, frag); |
1ae1602d CH |
716 | if (ret) { |
717 | detach_groups(group); | |
718 | break; | |
7063fbf2 | 719 | } |
7063fbf2 JB |
720 | } |
721 | ||
7063fbf2 JB |
722 | return ret; |
723 | } | |
724 | ||
1ae1602d CH |
725 | void configfs_remove_default_groups(struct config_group *group) |
726 | { | |
727 | struct config_group *g, *n; | |
728 | ||
729 | list_for_each_entry_safe(g, n, &group->default_groups, group_entry) { | |
730 | list_del(&g->group_entry); | |
731 | config_item_put(&g->cg_item); | |
732 | } | |
733 | } | |
734 | EXPORT_SYMBOL(configfs_remove_default_groups); | |
735 | ||
7063fbf2 JB |
736 | /* |
737 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 738 | * subsys->su_mutex is held. |
7063fbf2 JB |
739 | */ |
740 | ||
741 | static void unlink_obj(struct config_item *item) | |
742 | { | |
743 | struct config_group *group; | |
744 | ||
745 | group = item->ci_group; | |
746 | if (group) { | |
747 | list_del_init(&item->ci_entry); | |
748 | ||
749 | item->ci_group = NULL; | |
750 | item->ci_parent = NULL; | |
eed7a0db JB |
751 | |
752 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
753 | config_item_put(item); |
754 | ||
eed7a0db | 755 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
756 | config_group_put(group); |
757 | } | |
758 | } | |
759 | ||
760 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
761 | { | |
eed7a0db JB |
762 | /* |
763 | * Parent seems redundant with group, but it makes certain | |
764 | * traversals much nicer. | |
765 | */ | |
7063fbf2 | 766 | item->ci_parent = parent_item; |
eed7a0db JB |
767 | |
768 | /* | |
769 | * We hold a reference on the parent for the child's ci_parent | |
770 | * link. | |
771 | */ | |
7063fbf2 JB |
772 | item->ci_group = config_group_get(to_config_group(parent_item)); |
773 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
774 | ||
eed7a0db JB |
775 | /* |
776 | * We hold a reference on the child for ci_entry on the parent's | |
777 | * cg_children | |
778 | */ | |
7063fbf2 JB |
779 | config_item_get(item); |
780 | } | |
781 | ||
782 | static void unlink_group(struct config_group *group) | |
783 | { | |
7063fbf2 JB |
784 | struct config_group *new_group; |
785 | ||
1ae1602d CH |
786 | list_for_each_entry(new_group, &group->default_groups, group_entry) |
787 | unlink_group(new_group); | |
7063fbf2 JB |
788 | |
789 | group->cg_subsys = NULL; | |
790 | unlink_obj(&group->cg_item); | |
791 | } | |
792 | ||
793 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
794 | { | |
7063fbf2 JB |
795 | struct config_group *new_group; |
796 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
797 | ||
798 | link_obj(&parent_group->cg_item, &group->cg_item); | |
799 | ||
800 | if (parent_group->cg_subsys) | |
801 | subsys = parent_group->cg_subsys; | |
802 | else if (configfs_is_root(&parent_group->cg_item)) | |
803 | subsys = to_configfs_subsystem(group); | |
804 | else | |
805 | BUG(); | |
806 | group->cg_subsys = subsys; | |
807 | ||
1ae1602d CH |
808 | list_for_each_entry(new_group, &group->default_groups, group_entry) |
809 | link_group(group, new_group); | |
7063fbf2 JB |
810 | } |
811 | ||
812 | /* | |
813 | * The goal is that configfs_attach_item() (and | |
814 | * configfs_attach_group()) can be called from either the VFS or this | |
815 | * module. That is, they assume that the items have been created, | |
816 | * the dentry allocated, and the dcache is all ready to go. | |
817 | * | |
818 | * If they fail, they must clean up after themselves as if they | |
819 | * had never been called. The caller (VFS or local function) will | |
820 | * handle cleaning up the dcache bits. | |
821 | * | |
822 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
823 | * the way out. They assume that the proper semaphores are held, they | |
824 | * clean up the configfs items, and they expect their callers will | |
825 | * handle the dcache bits. | |
826 | */ | |
827 | static int configfs_attach_item(struct config_item *parent_item, | |
828 | struct config_item *item, | |
47320fbe AV |
829 | struct dentry *dentry, |
830 | struct configfs_fragment *frag) | |
7063fbf2 JB |
831 | { |
832 | int ret; | |
833 | ||
47320fbe | 834 | ret = configfs_create_dir(item, dentry, frag); |
7063fbf2 JB |
835 | if (!ret) { |
836 | ret = populate_attrs(item); | |
837 | if (ret) { | |
2e2ce171 LR |
838 | /* |
839 | * We are going to remove an inode and its dentry but | |
840 | * the VFS may already have hit and used them. Thus, | |
841 | * we must lock them as rmdir() would. | |
842 | */ | |
5955102c | 843 | inode_lock(d_inode(dentry)); |
7063fbf2 | 844 | configfs_remove_dir(item); |
2b0143b5 | 845 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 846 | dont_mount(dentry); |
5955102c | 847 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
848 | d_delete(dentry); |
849 | } | |
850 | } | |
851 | ||
852 | return ret; | |
853 | } | |
854 | ||
2e2ce171 | 855 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
856 | static void configfs_detach_item(struct config_item *item) |
857 | { | |
858 | detach_attrs(item); | |
859 | configfs_remove_dir(item); | |
860 | } | |
861 | ||
862 | static int configfs_attach_group(struct config_item *parent_item, | |
863 | struct config_item *item, | |
47320fbe AV |
864 | struct dentry *dentry, |
865 | struct configfs_fragment *frag) | |
7063fbf2 JB |
866 | { |
867 | int ret; | |
868 | struct configfs_dirent *sd; | |
869 | ||
47320fbe | 870 | ret = configfs_attach_item(parent_item, item, dentry, frag); |
7063fbf2 JB |
871 | if (!ret) { |
872 | sd = dentry->d_fsdata; | |
873 | sd->s_type |= CONFIGFS_USET_DIR; | |
874 | ||
2e2ce171 LR |
875 | /* |
876 | * FYI, we're faking mkdir in populate_groups() | |
877 | * We must lock the group's inode to avoid races with the VFS | |
878 | * which can already hit the inode and try to add/remove entries | |
879 | * under it. | |
880 | * | |
881 | * We must also lock the inode to remove it safely in case of | |
882 | * error, as rmdir() would. | |
883 | */ | |
5955102c | 884 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
e74cc06d | 885 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
47320fbe | 886 | ret = populate_groups(to_config_group(item), frag); |
7063fbf2 JB |
887 | if (ret) { |
888 | configfs_detach_item(item); | |
2b0143b5 | 889 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 890 | dont_mount(dentry); |
7063fbf2 | 891 | } |
e74cc06d | 892 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
5955102c | 893 | inode_unlock(d_inode(dentry)); |
2e2ce171 LR |
894 | if (ret) |
895 | d_delete(dentry); | |
7063fbf2 JB |
896 | } |
897 | ||
898 | return ret; | |
899 | } | |
900 | ||
2e2ce171 | 901 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
902 | static void configfs_detach_group(struct config_item *item) |
903 | { | |
904 | detach_groups(to_config_group(item)); | |
905 | configfs_detach_item(item); | |
906 | } | |
907 | ||
299894cc JB |
908 | /* |
909 | * After the item has been detached from the filesystem view, we are | |
910 | * ready to tear it out of the hierarchy. Notify the client before | |
911 | * we do that so they can perform any cleanup that requires | |
912 | * navigating the hierarchy. A client does not need to provide this | |
913 | * callback. The subsystem semaphore MUST be held by the caller, and | |
914 | * references must be valid for both items. It also assumes the | |
915 | * caller has validated ci_type. | |
916 | */ | |
917 | static void client_disconnect_notify(struct config_item *parent_item, | |
918 | struct config_item *item) | |
919 | { | |
aa293583 | 920 | const struct config_item_type *type; |
299894cc JB |
921 | |
922 | type = parent_item->ci_type; | |
923 | BUG_ON(!type); | |
924 | ||
925 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
926 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
927 | item); | |
928 | } | |
929 | ||
7063fbf2 JB |
930 | /* |
931 | * Drop the initial reference from make_item()/make_group() | |
932 | * This function assumes that reference is held on item | |
933 | * and that item holds a valid reference to the parent. Also, it | |
934 | * assumes the caller has validated ci_type. | |
935 | */ | |
936 | static void client_drop_item(struct config_item *parent_item, | |
937 | struct config_item *item) | |
938 | { | |
aa293583 | 939 | const struct config_item_type *type; |
7063fbf2 JB |
940 | |
941 | type = parent_item->ci_type; | |
942 | BUG_ON(!type); | |
943 | ||
eed7a0db JB |
944 | /* |
945 | * If ->drop_item() exists, it is responsible for the | |
946 | * config_item_put(). | |
947 | */ | |
7063fbf2 JB |
948 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
949 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 950 | item); |
7063fbf2 JB |
951 | else |
952 | config_item_put(item); | |
953 | } | |
954 | ||
631d1feb JB |
955 | #ifdef DEBUG |
956 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
957 | { | |
c6686931 | 958 | pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
631d1feb | 959 | |
c6686931 | 960 | #define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type); |
631d1feb JB |
961 | type_print(CONFIGFS_ROOT); |
962 | type_print(CONFIGFS_DIR); | |
963 | type_print(CONFIGFS_ITEM_ATTR); | |
964 | type_print(CONFIGFS_ITEM_LINK); | |
965 | type_print(CONFIGFS_USET_DIR); | |
966 | type_print(CONFIGFS_USET_DEFAULT); | |
967 | type_print(CONFIGFS_USET_DROPPING); | |
968 | #undef type_print | |
969 | } | |
970 | ||
971 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
972 | { | |
973 | struct configfs_dirent *child_sd; | |
974 | int ret = 0; | |
975 | ||
976 | configfs_dump_one(sd, level); | |
977 | ||
978 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
979 | return 0; | |
980 | ||
981 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
982 | ret = configfs_dump(child_sd, level + 2); | |
983 | if (ret) | |
984 | break; | |
985 | } | |
986 | ||
987 | return ret; | |
988 | } | |
989 | #endif | |
990 | ||
991 | ||
992 | /* | |
993 | * configfs_depend_item() and configfs_undepend_item() | |
994 | * | |
995 | * WARNING: Do not call these from a configfs callback! | |
996 | * | |
997 | * This describes these functions and their helpers. | |
998 | * | |
999 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 1000 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
1001 | * it. The idea is to give client modules as simple an interface as |
1002 | * possible. When a system asks them to depend on an item, they just | |
1003 | * call configfs_depend_item(). If the item is live and the client | |
1004 | * driver is in good shape, we'll happily do the work for them. | |
1005 | * | |
1006 | * Why is the locking complex? Because configfs uses the VFS to handle | |
1007 | * all locking, but this function is called outside the normal | |
1008 | * VFS->configfs path. So it must take VFS locks to prevent the | |
1009 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
1010 | * why you can't call these functions underneath configfs callbacks. | |
1011 | * | |
1012 | * Note, btw, that this can be called at *any* time, even when a configfs | |
1013 | * subsystem isn't registered, or when configfs is loading or unloading. | |
1014 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
1015 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
1016 | * If we can find the target item in the | |
631d1feb | 1017 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
1018 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1019 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
1020 | */ |
1021 | ||
1022 | /* | |
1023 | * configfs_depend_prep() | |
1024 | * | |
1025 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1026 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1027 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1028 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1029 | * do that so we can unlock it if we find nothing. | |
1030 | * | |
1031 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1032 | * our object. |
1033 | * We deliberately ignore items tagged as dropping since they are virtually | |
1034 | * dead, as well as items in the middle of attachment since they virtually | |
1035 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1036 | * rmdir(). | |
1037 | * Note: subdirectories in the middle of attachment start with s_type = | |
1038 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1039 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1040 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1041 | * |
420118ca | 1042 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1043 | * |
1044 | * This adds a requirement that all config_items be unique! | |
1045 | * | |
420118ca | 1046 | * This is recursive. There isn't |
631d1feb JB |
1047 | * much on the stack, though, so folks that need this function - be careful |
1048 | * about your stack! Patches will be accepted to make it iterative. | |
1049 | */ | |
1050 | static int configfs_depend_prep(struct dentry *origin, | |
1051 | struct config_item *target) | |
1052 | { | |
49deb4bc | 1053 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1054 | int ret = 0; |
1055 | ||
49deb4bc WY |
1056 | BUG_ON(!origin || !origin->d_fsdata); |
1057 | sd = origin->d_fsdata; | |
631d1feb | 1058 | |
631d1feb JB |
1059 | if (sd->s_element == target) /* Boo-yah */ |
1060 | goto out; | |
1061 | ||
1062 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1063 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1064 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1065 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1066 | ret = configfs_depend_prep(child_sd->s_dentry, |
1067 | target); | |
1068 | if (!ret) | |
1069 | goto out; /* Child path boo-yah */ | |
1070 | } | |
1071 | } | |
1072 | ||
1073 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1074 | ret = -ENOENT; |
1075 | ||
1076 | out: | |
1077 | return ret; | |
1078 | } | |
1079 | ||
9fb434e7 KO |
1080 | static int configfs_do_depend_item(struct dentry *subsys_dentry, |
1081 | struct config_item *target) | |
1082 | { | |
1083 | struct configfs_dirent *p; | |
1084 | int ret; | |
1085 | ||
1086 | spin_lock(&configfs_dirent_lock); | |
1087 | /* Scan the tree, return 0 if found */ | |
1088 | ret = configfs_depend_prep(subsys_dentry, target); | |
1089 | if (ret) | |
1090 | goto out_unlock_dirent_lock; | |
1091 | ||
1092 | /* | |
1093 | * We are sure that the item is not about to be removed by rmdir(), and | |
1094 | * not in the middle of attachment by mkdir(). | |
1095 | */ | |
1096 | p = target->ci_dentry->d_fsdata; | |
1097 | p->s_dependent_count += 1; | |
1098 | ||
1099 | out_unlock_dirent_lock: | |
1100 | spin_unlock(&configfs_dirent_lock); | |
1101 | ||
1102 | return ret; | |
1103 | } | |
1104 | ||
9a70adff KO |
1105 | static inline struct configfs_dirent * |
1106 | configfs_find_subsys_dentry(struct configfs_dirent *root_sd, | |
1107 | struct config_item *subsys_item) | |
1108 | { | |
1109 | struct configfs_dirent *p; | |
1110 | struct configfs_dirent *ret = NULL; | |
1111 | ||
1112 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1113 | if (p->s_type & CONFIGFS_DIR && | |
1114 | p->s_element == subsys_item) { | |
1115 | ret = p; | |
1116 | break; | |
1117 | } | |
1118 | } | |
1119 | ||
1120 | return ret; | |
1121 | } | |
1122 | ||
1123 | ||
631d1feb JB |
1124 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1125 | struct config_item *target) | |
1126 | { | |
1127 | int ret; | |
9a70adff | 1128 | struct configfs_dirent *subsys_sd; |
631d1feb | 1129 | struct config_item *s_item = &subsys->su_group.cg_item; |
b7c177fc | 1130 | struct dentry *root; |
631d1feb JB |
1131 | |
1132 | /* | |
1133 | * Pin the configfs filesystem. This means we can safely access | |
1134 | * the root of the configfs filesystem. | |
1135 | */ | |
2a152ad3 AV |
1136 | root = configfs_pin_fs(); |
1137 | if (IS_ERR(root)) | |
1138 | return PTR_ERR(root); | |
631d1feb JB |
1139 | |
1140 | /* | |
1141 | * Next, lock the root directory. We're going to check that the | |
1142 | * subsystem is really registered, and so we need to lock out | |
1143 | * configfs_[un]register_subsystem(). | |
1144 | */ | |
5955102c | 1145 | inode_lock(d_inode(root)); |
631d1feb | 1146 | |
9a70adff | 1147 | subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item); |
631d1feb JB |
1148 | if (!subsys_sd) { |
1149 | ret = -ENOENT; | |
1150 | goto out_unlock_fs; | |
1151 | } | |
1152 | ||
1153 | /* Ok, now we can trust subsys/s_item */ | |
9fb434e7 | 1154 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); |
631d1feb | 1155 | |
631d1feb | 1156 | out_unlock_fs: |
5955102c | 1157 | inode_unlock(d_inode(root)); |
631d1feb JB |
1158 | |
1159 | /* | |
1160 | * If we succeeded, the fs is pinned via other methods. If not, | |
1161 | * we're done with it anyway. So release_fs() is always right. | |
1162 | */ | |
1163 | configfs_release_fs(); | |
1164 | ||
1165 | return ret; | |
1166 | } | |
1167 | EXPORT_SYMBOL(configfs_depend_item); | |
1168 | ||
1169 | /* | |
1170 | * Release the dependent linkage. This is much simpler than | |
ce9bebe6 | 1171 | * configfs_depend_item() because we know that the client driver is |
631d1feb JB |
1172 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. |
1173 | */ | |
9a9e3415 | 1174 | void configfs_undepend_item(struct config_item *target) |
631d1feb JB |
1175 | { |
1176 | struct configfs_dirent *sd; | |
1177 | ||
1178 | /* | |
420118ca LR |
1179 | * Since we can trust everything is pinned, we just need |
1180 | * configfs_dirent_lock. | |
631d1feb | 1181 | */ |
420118ca | 1182 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1183 | |
1184 | sd = target->ci_dentry->d_fsdata; | |
1185 | BUG_ON(sd->s_dependent_count < 1); | |
1186 | ||
1187 | sd->s_dependent_count -= 1; | |
1188 | ||
1189 | /* | |
1190 | * After this unlock, we cannot trust the item to stay alive! | |
1191 | * DO NOT REFERENCE item after this unlock. | |
1192 | */ | |
420118ca | 1193 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1194 | } |
1195 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1196 | |
d79d75b5 KO |
1197 | /* |
1198 | * caller_subsys is a caller's subsystem not target's. This is used to | |
1199 | * determine if we should lock root and check subsys or not. When we are | |
1200 | * in the same subsystem as our target there is no need to do locking as | |
1201 | * we know that subsys is valid and is not unregistered during this function | |
1202 | * as we are called from callback of one of his children and VFS holds a lock | |
1203 | * on some inode. Otherwise we have to lock our root to ensure that target's | |
1204 | * subsystem it is not unregistered during this function. | |
1205 | */ | |
1206 | int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, | |
1207 | struct config_item *target) | |
1208 | { | |
1209 | struct configfs_subsystem *target_subsys; | |
1210 | struct config_group *root, *parent; | |
1211 | struct configfs_dirent *subsys_sd; | |
1212 | int ret = -ENOENT; | |
1213 | ||
1214 | /* Disallow this function for configfs root */ | |
1215 | if (configfs_is_root(target)) | |
1216 | return -EINVAL; | |
1217 | ||
1218 | parent = target->ci_group; | |
1219 | /* | |
1220 | * This may happen when someone is trying to depend root | |
1221 | * directory of some subsystem | |
1222 | */ | |
1223 | if (configfs_is_root(&parent->cg_item)) { | |
1224 | target_subsys = to_configfs_subsystem(to_config_group(target)); | |
1225 | root = parent; | |
1226 | } else { | |
1227 | target_subsys = parent->cg_subsys; | |
1228 | /* Find a cofnigfs root as we may need it for locking */ | |
1229 | for (root = parent; !configfs_is_root(&root->cg_item); | |
1230 | root = root->cg_item.ci_group) | |
1231 | ; | |
1232 | } | |
1233 | ||
1234 | if (target_subsys != caller_subsys) { | |
1235 | /* | |
1236 | * We are in other configfs subsystem, so we have to do | |
1237 | * additional locking to prevent other subsystem from being | |
1238 | * unregistered | |
1239 | */ | |
5955102c | 1240 | inode_lock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1241 | |
1242 | /* | |
1243 | * As we are trying to depend item from other subsystem | |
1244 | * we have to check if this subsystem is still registered | |
1245 | */ | |
1246 | subsys_sd = configfs_find_subsys_dentry( | |
1247 | root->cg_item.ci_dentry->d_fsdata, | |
1248 | &target_subsys->su_group.cg_item); | |
1249 | if (!subsys_sd) | |
1250 | goto out_root_unlock; | |
1251 | } else { | |
1252 | subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata; | |
1253 | } | |
1254 | ||
1255 | /* Now we can execute core of depend item */ | |
1256 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); | |
1257 | ||
1258 | if (target_subsys != caller_subsys) | |
1259 | out_root_unlock: | |
1260 | /* | |
1261 | * We were called from subsystem other than our target so we | |
1262 | * took some locks so now it's time to release them | |
1263 | */ | |
5955102c | 1264 | inode_unlock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1265 | |
1266 | return ret; | |
1267 | } | |
1268 | EXPORT_SYMBOL(configfs_depend_item_unlocked); | |
1269 | ||
549c7297 CB |
1270 | static int configfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, |
1271 | struct dentry *dentry, umode_t mode) | |
7063fbf2 | 1272 | { |
a6795e9e JB |
1273 | int ret = 0; |
1274 | int module_got = 0; | |
1275 | struct config_group *group = NULL; | |
1276 | struct config_item *item = NULL; | |
7063fbf2 JB |
1277 | struct config_item *parent_item; |
1278 | struct configfs_subsystem *subsys; | |
1279 | struct configfs_dirent *sd; | |
aa293583 | 1280 | const struct config_item_type *type; |
70526b67 | 1281 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
47320fbe | 1282 | struct configfs_fragment *frag; |
7063fbf2 JB |
1283 | char *name; |
1284 | ||
7063fbf2 | 1285 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1286 | |
1287 | /* | |
1288 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1289 | * being attached | |
1290 | */ | |
1291 | if (!configfs_dirent_is_ready(sd)) { | |
1292 | ret = -ENOENT; | |
1293 | goto out; | |
1294 | } | |
1295 | ||
84efad1a JB |
1296 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1297 | ret = -EPERM; | |
1298 | goto out; | |
1299 | } | |
7063fbf2 | 1300 | |
47320fbe AV |
1301 | frag = new_fragment(); |
1302 | if (!frag) { | |
1303 | ret = -ENOMEM; | |
1304 | goto out; | |
1305 | } | |
1306 | ||
84efad1a | 1307 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1308 | parent_item = configfs_get_config_item(dentry->d_parent); |
1309 | type = parent_item->ci_type; | |
1310 | subsys = to_config_group(parent_item)->cg_subsys; | |
1311 | BUG_ON(!subsys); | |
1312 | ||
1313 | if (!type || !type->ct_group_ops || | |
1314 | (!type->ct_group_ops->make_group && | |
1315 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1316 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1317 | goto out_put; | |
7063fbf2 JB |
1318 | } |
1319 | ||
70526b67 JB |
1320 | /* |
1321 | * The subsystem may belong to a different module than the item | |
1322 | * being created. We don't want to safely pin the new item but | |
1323 | * fail to pin the subsystem it sits under. | |
1324 | */ | |
1325 | if (!subsys->su_group.cg_item.ci_type) { | |
1326 | ret = -EINVAL; | |
1327 | goto out_put; | |
1328 | } | |
1329 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1330 | if (!try_module_get(subsys_owner)) { | |
1331 | ret = -EINVAL; | |
1332 | goto out_put; | |
1333 | } | |
1334 | ||
7063fbf2 JB |
1335 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1336 | if (!name) { | |
84efad1a | 1337 | ret = -ENOMEM; |
70526b67 | 1338 | goto out_subsys_put; |
7063fbf2 | 1339 | } |
84efad1a | 1340 | |
7063fbf2 JB |
1341 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1342 | ||
e6bd07ae | 1343 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1344 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1345 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1346 | if (!group) |
1347 | group = ERR_PTR(-ENOMEM); | |
1348 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1349 | link_group(to_config_group(parent_item), group); |
1350 | item = &group->cg_item; | |
a6795e9e JB |
1351 | } else |
1352 | ret = PTR_ERR(group); | |
7063fbf2 | 1353 | } else { |
f89ab861 | 1354 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1355 | if (!item) |
1356 | item = ERR_PTR(-ENOMEM); | |
1357 | if (!IS_ERR(item)) | |
7063fbf2 | 1358 | link_obj(parent_item, item); |
a6795e9e JB |
1359 | else |
1360 | ret = PTR_ERR(item); | |
7063fbf2 | 1361 | } |
e6bd07ae | 1362 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1363 | |
1364 | kfree(name); | |
a6795e9e | 1365 | if (ret) { |
eed7a0db | 1366 | /* |
dacdd0e0 | 1367 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1368 | * There are no extra references to clean up. |
1369 | */ | |
70526b67 | 1370 | goto out_subsys_put; |
7063fbf2 JB |
1371 | } |
1372 | ||
eed7a0db JB |
1373 | /* |
1374 | * link_obj() has been called (via link_group() for groups). | |
1375 | * From here on out, errors must clean that up. | |
1376 | */ | |
1377 | ||
7063fbf2 | 1378 | type = item->ci_type; |
eed7a0db JB |
1379 | if (!type) { |
1380 | ret = -EINVAL; | |
1381 | goto out_unlink; | |
1382 | } | |
7063fbf2 | 1383 | |
70526b67 JB |
1384 | new_item_owner = type->ct_owner; |
1385 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1386 | ret = -EINVAL; |
1387 | goto out_unlink; | |
1388 | } | |
7063fbf2 | 1389 | |
eed7a0db JB |
1390 | /* |
1391 | * I hate doing it this way, but if there is | |
1392 | * an error, module_put() probably should | |
1393 | * happen after any cleanup. | |
1394 | */ | |
1395 | module_got = 1; | |
1396 | ||
6d8344ba LR |
1397 | /* |
1398 | * Make racing rmdir() fail if it did not tag parent with | |
1399 | * CONFIGFS_USET_DROPPING | |
1400 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1401 | * fail and let rmdir() terminate correctly | |
1402 | */ | |
1403 | spin_lock(&configfs_dirent_lock); | |
1404 | /* This will make configfs_detach_prep() fail */ | |
1405 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1406 | spin_unlock(&configfs_dirent_lock); | |
1407 | ||
eed7a0db | 1408 | if (group) |
47320fbe | 1409 | ret = configfs_attach_group(parent_item, item, dentry, frag); |
eed7a0db | 1410 | else |
47320fbe | 1411 | ret = configfs_attach_item(parent_item, item, dentry, frag); |
eed7a0db | 1412 | |
6d8344ba LR |
1413 | spin_lock(&configfs_dirent_lock); |
1414 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1415 | if (!ret) |
1416 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1417 | spin_unlock(&configfs_dirent_lock); |
1418 | ||
eed7a0db JB |
1419 | out_unlink: |
1420 | if (ret) { | |
1421 | /* Tear down everything we built up */ | |
e6bd07ae | 1422 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1423 | |
1424 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1425 | if (group) |
1426 | unlink_group(group); | |
1427 | else | |
1428 | unlink_obj(item); | |
1429 | client_drop_item(parent_item, item); | |
299894cc | 1430 | |
e6bd07ae | 1431 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1432 | |
1433 | if (module_got) | |
70526b67 | 1434 | module_put(new_item_owner); |
7063fbf2 JB |
1435 | } |
1436 | ||
70526b67 JB |
1437 | out_subsys_put: |
1438 | if (ret) | |
1439 | module_put(subsys_owner); | |
1440 | ||
84efad1a JB |
1441 | out_put: |
1442 | /* | |
eed7a0db JB |
1443 | * link_obj()/link_group() took a reference from child->parent, |
1444 | * so the parent is safely pinned. We can drop our working | |
1445 | * reference. | |
84efad1a JB |
1446 | */ |
1447 | config_item_put(parent_item); | |
47320fbe | 1448 | put_fragment(frag); |
84efad1a JB |
1449 | |
1450 | out: | |
7063fbf2 JB |
1451 | return ret; |
1452 | } | |
1453 | ||
1454 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1455 | { | |
1456 | struct config_item *parent_item; | |
1457 | struct config_item *item; | |
1458 | struct configfs_subsystem *subsys; | |
1459 | struct configfs_dirent *sd; | |
b0841eef | 1460 | struct configfs_fragment *frag; |
70526b67 | 1461 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1462 | int ret; |
1463 | ||
7063fbf2 JB |
1464 | sd = dentry->d_fsdata; |
1465 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1466 | return -EPERM; | |
1467 | ||
84efad1a | 1468 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1469 | parent_item = configfs_get_config_item(dentry->d_parent); |
1470 | subsys = to_config_group(parent_item)->cg_subsys; | |
1471 | BUG_ON(!subsys); | |
1472 | ||
1473 | if (!parent_item->ci_type) { | |
1474 | config_item_put(parent_item); | |
1475 | return -EINVAL; | |
1476 | } | |
1477 | ||
70526b67 JB |
1478 | /* configfs_mkdir() shouldn't have allowed this */ |
1479 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1480 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1481 | ||
9a73d78c LR |
1482 | /* |
1483 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1484 | * the new link is temporarily attached | |
1485 | */ | |
6d8344ba | 1486 | do { |
48f35b7b | 1487 | struct dentry *wait; |
6d8344ba | 1488 | |
de6bf18e LR |
1489 | mutex_lock(&configfs_symlink_mutex); |
1490 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1491 | /* |
1492 | * Here's where we check for dependents. We're protected by | |
1493 | * configfs_dirent_lock. | |
1494 | * If no dependent, atomically tag the item as dropping. | |
1495 | */ | |
1496 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1497 | if (!ret) { | |
48f35b7b | 1498 | ret = configfs_detach_prep(dentry, &wait); |
420118ca LR |
1499 | if (ret) |
1500 | configfs_detach_rollback(dentry); | |
1501 | } | |
de6bf18e LR |
1502 | spin_unlock(&configfs_dirent_lock); |
1503 | mutex_unlock(&configfs_symlink_mutex); | |
1504 | ||
1505 | if (ret) { | |
6d8344ba LR |
1506 | if (ret != -EAGAIN) { |
1507 | config_item_put(parent_item); | |
1508 | return ret; | |
1509 | } | |
1510 | ||
1511 | /* Wait until the racing operation terminates */ | |
48f35b7b AV |
1512 | inode_lock(d_inode(wait)); |
1513 | inode_unlock(d_inode(wait)); | |
1514 | dput(wait); | |
6d8344ba LR |
1515 | } |
1516 | } while (ret == -EAGAIN); | |
7063fbf2 | 1517 | |
b0841eef AV |
1518 | frag = sd->s_frag; |
1519 | if (down_write_killable(&frag->frag_sem)) { | |
1520 | spin_lock(&configfs_dirent_lock); | |
1521 | configfs_detach_rollback(dentry); | |
1522 | spin_unlock(&configfs_dirent_lock); | |
8aebfffa | 1523 | config_item_put(parent_item); |
b0841eef AV |
1524 | return -EINTR; |
1525 | } | |
1526 | frag->frag_dead = true; | |
1527 | up_write(&frag->frag_sem); | |
1528 | ||
84efad1a | 1529 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1530 | item = configfs_get_config_item(dentry); |
1531 | ||
1532 | /* Drop reference from above, item already holds one. */ | |
1533 | config_item_put(parent_item); | |
1534 | ||
1535 | if (item->ci_type) | |
70526b67 | 1536 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1537 | |
1538 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1539 | configfs_detach_group(item); | |
1540 | ||
e6bd07ae | 1541 | mutex_lock(&subsys->su_mutex); |
299894cc | 1542 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1543 | unlink_group(to_config_group(item)); |
1544 | } else { | |
1545 | configfs_detach_item(item); | |
1546 | ||
e6bd07ae | 1547 | mutex_lock(&subsys->su_mutex); |
299894cc | 1548 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1549 | unlink_obj(item); |
1550 | } | |
1551 | ||
1552 | client_drop_item(parent_item, item); | |
e6bd07ae | 1553 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1554 | |
1555 | /* Drop our reference from above */ | |
1556 | config_item_put(item); | |
1557 | ||
70526b67 JB |
1558 | module_put(dead_item_owner); |
1559 | module_put(subsys_owner); | |
7063fbf2 JB |
1560 | |
1561 | return 0; | |
1562 | } | |
1563 | ||
754661f1 | 1564 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1565 | .mkdir = configfs_mkdir, |
1566 | .rmdir = configfs_rmdir, | |
1567 | .symlink = configfs_symlink, | |
1568 | .unlink = configfs_unlink, | |
1569 | .lookup = configfs_lookup, | |
3d0f89bb | 1570 | .setattr = configfs_setattr, |
7063fbf2 JB |
1571 | }; |
1572 | ||
81d44ed1 AV |
1573 | const struct inode_operations configfs_root_inode_operations = { |
1574 | .lookup = configfs_lookup, | |
1575 | .setattr = configfs_setattr, | |
1576 | }; | |
1577 | ||
7063fbf2 JB |
1578 | static int configfs_dir_open(struct inode *inode, struct file *file) |
1579 | { | |
867fa491 | 1580 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1581 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1582 | int err; |
7063fbf2 | 1583 | |
5955102c | 1584 | inode_lock(d_inode(dentry)); |
2a109f2a LR |
1585 | /* |
1586 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1587 | * being attached | |
1588 | */ | |
1589 | err = -ENOENT; | |
1590 | if (configfs_dirent_is_ready(parent_sd)) { | |
47320fbe | 1591 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0, NULL); |
2a109f2a LR |
1592 | if (IS_ERR(file->private_data)) |
1593 | err = PTR_ERR(file->private_data); | |
1594 | else | |
1595 | err = 0; | |
1596 | } | |
5955102c | 1597 | inode_unlock(d_inode(dentry)); |
7063fbf2 | 1598 | |
2a109f2a | 1599 | return err; |
7063fbf2 JB |
1600 | } |
1601 | ||
1602 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1603 | { | |
867fa491 | 1604 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1605 | struct configfs_dirent * cursor = file->private_data; |
1606 | ||
5955102c | 1607 | inode_lock(d_inode(dentry)); |
6f610764 | 1608 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1609 | list_del_init(&cursor->s_sibling); |
6f610764 | 1610 | spin_unlock(&configfs_dirent_lock); |
5955102c | 1611 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
1612 | |
1613 | release_configfs_dirent(cursor); | |
1614 | ||
1615 | return 0; | |
1616 | } | |
1617 | ||
1618 | /* Relationship between s_mode and the DT_xxx types */ | |
1619 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1620 | { | |
1621 | return (sd->s_mode >> 12) & 15; | |
1622 | } | |
1623 | ||
52018855 | 1624 | static int configfs_readdir(struct file *file, struct dir_context *ctx) |
7063fbf2 | 1625 | { |
52018855 | 1626 | struct dentry *dentry = file->f_path.dentry; |
b7c177fc | 1627 | struct super_block *sb = dentry->d_sb; |
7063fbf2 | 1628 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
52018855 | 1629 | struct configfs_dirent *cursor = file->private_data; |
7063fbf2 | 1630 | struct list_head *p, *q = &cursor->s_sibling; |
24307aa1 | 1631 | ino_t ino = 0; |
7063fbf2 | 1632 | |
52018855 AV |
1633 | if (!dir_emit_dots(file, ctx)) |
1634 | return 0; | |
a01b3007 AV |
1635 | spin_lock(&configfs_dirent_lock); |
1636 | if (ctx->pos == 2) | |
52018855 | 1637 | list_move(q, &parent_sd->s_children); |
52018855 AV |
1638 | for (p = q->next; p != &parent_sd->s_children; p = p->next) { |
1639 | struct configfs_dirent *next; | |
1640 | const char *name; | |
1641 | int len; | |
1642 | struct inode *inode = NULL; | |
1643 | ||
1644 | next = list_entry(p, struct configfs_dirent, s_sibling); | |
1645 | if (!next->s_element) | |
1646 | continue; | |
7063fbf2 | 1647 | |
52018855 AV |
1648 | /* |
1649 | * We'll have a dentry and an inode for | |
1650 | * PINNED items and for open attribute | |
1651 | * files. We lock here to prevent a race | |
1652 | * with configfs_d_iput() clearing | |
1653 | * s_dentry before calling iput(). | |
1654 | * | |
1655 | * Why do we go to the trouble? If | |
1656 | * someone has an attribute file open, | |
1657 | * the inode number should match until | |
1658 | * they close it. Beyond that, we don't | |
1659 | * care. | |
1660 | */ | |
52018855 AV |
1661 | dentry = next->s_dentry; |
1662 | if (dentry) | |
2b0143b5 | 1663 | inode = d_inode(dentry); |
52018855 AV |
1664 | if (inode) |
1665 | ino = inode->i_ino; | |
1666 | spin_unlock(&configfs_dirent_lock); | |
1667 | if (!inode) | |
1668 | ino = iunique(sb, 2); | |
7063fbf2 | 1669 | |
a01b3007 AV |
1670 | name = configfs_get_name(next); |
1671 | len = strlen(name); | |
1672 | ||
52018855 AV |
1673 | if (!dir_emit(ctx, name, len, ino, dt_type(next))) |
1674 | return 0; | |
7063fbf2 | 1675 | |
52018855 AV |
1676 | spin_lock(&configfs_dirent_lock); |
1677 | list_move(q, p); | |
52018855 AV |
1678 | p = q; |
1679 | ctx->pos++; | |
7063fbf2 | 1680 | } |
a01b3007 | 1681 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1682 | return 0; |
1683 | } | |
1684 | ||
965c8e59 | 1685 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1686 | { |
867fa491 | 1687 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1688 | |
965c8e59 | 1689 | switch (whence) { |
7063fbf2 JB |
1690 | case 1: |
1691 | offset += file->f_pos; | |
df561f66 | 1692 | fallthrough; |
7063fbf2 JB |
1693 | case 0: |
1694 | if (offset >= 0) | |
1695 | break; | |
df561f66 | 1696 | fallthrough; |
7063fbf2 | 1697 | default: |
7063fbf2 JB |
1698 | return -EINVAL; |
1699 | } | |
1700 | if (offset != file->f_pos) { | |
1701 | file->f_pos = offset; | |
1702 | if (file->f_pos >= 2) { | |
1703 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1704 | struct configfs_dirent *cursor = file->private_data; | |
1705 | struct list_head *p; | |
1706 | loff_t n = file->f_pos - 2; | |
1707 | ||
6f610764 | 1708 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1709 | list_del(&cursor->s_sibling); |
1710 | p = sd->s_children.next; | |
1711 | while (n && p != &sd->s_children) { | |
1712 | struct configfs_dirent *next; | |
1713 | next = list_entry(p, struct configfs_dirent, | |
1714 | s_sibling); | |
1715 | if (next->s_element) | |
1716 | n--; | |
1717 | p = p->next; | |
1718 | } | |
1719 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1720 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1721 | } |
1722 | } | |
7063fbf2 JB |
1723 | return offset; |
1724 | } | |
1725 | ||
4b6f5d20 | 1726 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1727 | .open = configfs_dir_open, |
1728 | .release = configfs_dir_close, | |
1729 | .llseek = configfs_dir_lseek, | |
1730 | .read = generic_read_dir, | |
a01b3007 | 1731 | .iterate_shared = configfs_readdir, |
7063fbf2 JB |
1732 | }; |
1733 | ||
5cf6a51e DB |
1734 | /** |
1735 | * configfs_register_group - creates a parent-child relation between two groups | |
1736 | * @parent_group: parent group | |
1737 | * @group: child group | |
1738 | * | |
1739 | * link groups, creates dentry for the child and attaches it to the | |
1740 | * parent dentry. | |
1741 | * | |
1742 | * Return: 0 on success, negative errno code on error | |
1743 | */ | |
1744 | int configfs_register_group(struct config_group *parent_group, | |
1745 | struct config_group *group) | |
1746 | { | |
1747 | struct configfs_subsystem *subsys = parent_group->cg_subsys; | |
1748 | struct dentry *parent; | |
47320fbe | 1749 | struct configfs_fragment *frag; |
5cf6a51e DB |
1750 | int ret; |
1751 | ||
47320fbe AV |
1752 | frag = new_fragment(); |
1753 | if (!frag) | |
1754 | return -ENOMEM; | |
1755 | ||
5cf6a51e DB |
1756 | mutex_lock(&subsys->su_mutex); |
1757 | link_group(parent_group, group); | |
1758 | mutex_unlock(&subsys->su_mutex); | |
1759 | ||
1760 | parent = parent_group->cg_item.ci_dentry; | |
1761 | ||
5955102c | 1762 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
47320fbe | 1763 | ret = create_default_group(parent_group, group, frag); |
35399f87 Y |
1764 | if (ret) |
1765 | goto err_out; | |
1766 | ||
1767 | spin_lock(&configfs_dirent_lock); | |
1768 | configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); | |
1769 | spin_unlock(&configfs_dirent_lock); | |
1770 | inode_unlock(d_inode(parent)); | |
47320fbe | 1771 | put_fragment(frag); |
35399f87 Y |
1772 | return 0; |
1773 | err_out: | |
5955102c | 1774 | inode_unlock(d_inode(parent)); |
35399f87 Y |
1775 | mutex_lock(&subsys->su_mutex); |
1776 | unlink_group(group); | |
1777 | mutex_unlock(&subsys->su_mutex); | |
47320fbe | 1778 | put_fragment(frag); |
5cf6a51e DB |
1779 | return ret; |
1780 | } | |
1781 | EXPORT_SYMBOL(configfs_register_group); | |
1782 | ||
1783 | /** | |
1784 | * configfs_unregister_group() - unregisters a child group from its parent | |
1785 | * @group: parent group to be unregistered | |
1786 | * | |
1787 | * Undoes configfs_register_group() | |
1788 | */ | |
1789 | void configfs_unregister_group(struct config_group *group) | |
1790 | { | |
1791 | struct configfs_subsystem *subsys = group->cg_subsys; | |
1792 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1793 | struct dentry *parent = group->cg_item.ci_parent->ci_dentry; | |
b0841eef AV |
1794 | struct configfs_dirent *sd = dentry->d_fsdata; |
1795 | struct configfs_fragment *frag = sd->s_frag; | |
1796 | ||
1797 | down_write(&frag->frag_sem); | |
1798 | frag->frag_dead = true; | |
1799 | up_write(&frag->frag_sem); | |
5cf6a51e | 1800 | |
5955102c | 1801 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
5cf6a51e DB |
1802 | spin_lock(&configfs_dirent_lock); |
1803 | configfs_detach_prep(dentry, NULL); | |
1804 | spin_unlock(&configfs_dirent_lock); | |
1805 | ||
1806 | configfs_detach_group(&group->cg_item); | |
1807 | d_inode(dentry)->i_flags |= S_DEAD; | |
1808 | dont_mount(dentry); | |
6146e78c | 1809 | fsnotify_rmdir(d_inode(parent), dentry); |
5cf6a51e | 1810 | d_delete(dentry); |
5955102c | 1811 | inode_unlock(d_inode(parent)); |
5cf6a51e DB |
1812 | |
1813 | dput(dentry); | |
1814 | ||
1815 | mutex_lock(&subsys->su_mutex); | |
1816 | unlink_group(group); | |
1817 | mutex_unlock(&subsys->su_mutex); | |
1818 | } | |
1819 | EXPORT_SYMBOL(configfs_unregister_group); | |
1820 | ||
1821 | /** | |
1822 | * configfs_register_default_group() - allocates and registers a child group | |
1823 | * @parent_group: parent group | |
1824 | * @name: child group name | |
1825 | * @item_type: child item type description | |
1826 | * | |
1827 | * boilerplate to allocate and register a child group with its parent. We need | |
1828 | * kzalloc'ed memory because child's default_group is initially empty. | |
1829 | * | |
1830 | * Return: allocated config group or ERR_PTR() on error | |
1831 | */ | |
1832 | struct config_group * | |
1833 | configfs_register_default_group(struct config_group *parent_group, | |
1834 | const char *name, | |
aa293583 | 1835 | const struct config_item_type *item_type) |
5cf6a51e DB |
1836 | { |
1837 | int ret; | |
1838 | struct config_group *group; | |
1839 | ||
1840 | group = kzalloc(sizeof(*group), GFP_KERNEL); | |
1841 | if (!group) | |
1842 | return ERR_PTR(-ENOMEM); | |
1843 | config_group_init_type_name(group, name, item_type); | |
1844 | ||
1845 | ret = configfs_register_group(parent_group, group); | |
1846 | if (ret) { | |
1847 | kfree(group); | |
1848 | return ERR_PTR(ret); | |
1849 | } | |
1850 | return group; | |
1851 | } | |
1852 | EXPORT_SYMBOL(configfs_register_default_group); | |
1853 | ||
1854 | /** | |
1855 | * configfs_unregister_default_group() - unregisters and frees a child group | |
1856 | * @group: the group to act on | |
1857 | */ | |
1858 | void configfs_unregister_default_group(struct config_group *group) | |
1859 | { | |
1860 | configfs_unregister_group(group); | |
1861 | kfree(group); | |
1862 | } | |
1863 | EXPORT_SYMBOL(configfs_unregister_default_group); | |
1864 | ||
7063fbf2 JB |
1865 | int configfs_register_subsystem(struct configfs_subsystem *subsys) |
1866 | { | |
1867 | int err; | |
1868 | struct config_group *group = &subsys->su_group; | |
7063fbf2 | 1869 | struct dentry *dentry; |
b7c177fc | 1870 | struct dentry *root; |
7063fbf2 | 1871 | struct configfs_dirent *sd; |
47320fbe AV |
1872 | struct configfs_fragment *frag; |
1873 | ||
1874 | frag = new_fragment(); | |
1875 | if (!frag) | |
1876 | return -ENOMEM; | |
7063fbf2 | 1877 | |
2a152ad3 | 1878 | root = configfs_pin_fs(); |
47320fbe AV |
1879 | if (IS_ERR(root)) { |
1880 | put_fragment(frag); | |
2a152ad3 | 1881 | return PTR_ERR(root); |
47320fbe | 1882 | } |
7063fbf2 JB |
1883 | |
1884 | if (!group->cg_item.ci_name) | |
1885 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1886 | ||
b7c177fc | 1887 | sd = root->d_fsdata; |
7063fbf2 JB |
1888 | link_group(to_config_group(sd->s_element), group); |
1889 | ||
5955102c | 1890 | inode_lock_nested(d_inode(root), I_MUTEX_PARENT); |
7063fbf2 | 1891 | |
7063fbf2 | 1892 | err = -ENOMEM; |
ec193cf5 | 1893 | dentry = d_alloc_name(root, group->cg_item.ci_name); |
afdf04ea JB |
1894 | if (dentry) { |
1895 | d_add(dentry, NULL); | |
7063fbf2 | 1896 | |
afdf04ea | 1897 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
47320fbe | 1898 | dentry, frag); |
afdf04ea | 1899 | if (err) { |
2b0143b5 | 1900 | BUG_ON(d_inode(dentry)); |
df7f9967 | 1901 | d_drop(dentry); |
afdf04ea | 1902 | dput(dentry); |
2a109f2a LR |
1903 | } else { |
1904 | spin_lock(&configfs_dirent_lock); | |
1905 | configfs_dir_set_ready(dentry->d_fsdata); | |
1906 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1907 | } |
1908 | } | |
7063fbf2 | 1909 | |
5955102c | 1910 | inode_unlock(d_inode(root)); |
7063fbf2 | 1911 | |
afdf04ea JB |
1912 | if (err) { |
1913 | unlink_group(group); | |
1914 | configfs_release_fs(); | |
7063fbf2 | 1915 | } |
47320fbe | 1916 | put_fragment(frag); |
7063fbf2 JB |
1917 | |
1918 | return err; | |
1919 | } | |
1920 | ||
1921 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1922 | { | |
1923 | struct config_group *group = &subsys->su_group; | |
1924 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1925 | struct dentry *root = dentry->d_sb->s_root; |
b0841eef AV |
1926 | struct configfs_dirent *sd = dentry->d_fsdata; |
1927 | struct configfs_fragment *frag = sd->s_frag; | |
7063fbf2 | 1928 | |
b7c177fc | 1929 | if (dentry->d_parent != root) { |
1d88aa44 | 1930 | pr_err("Tried to unregister non-subsystem!\n"); |
7063fbf2 JB |
1931 | return; |
1932 | } | |
1933 | ||
b0841eef AV |
1934 | down_write(&frag->frag_sem); |
1935 | frag->frag_dead = true; | |
1936 | up_write(&frag->frag_sem); | |
1937 | ||
5955102c | 1938 | inode_lock_nested(d_inode(root), |
55ed1602 | 1939 | I_MUTEX_PARENT); |
5955102c | 1940 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
9a73d78c | 1941 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1942 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1943 | if (configfs_detach_prep(dentry, NULL)) { |
1d88aa44 | 1944 | pr_err("Tried to unregister non-empty subsystem!\n"); |
7063fbf2 | 1945 | } |
b3e76af8 | 1946 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1947 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 | 1948 | configfs_detach_group(&group->cg_item); |
2b0143b5 | 1949 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 1950 | dont_mount(dentry); |
6146e78c | 1951 | fsnotify_rmdir(d_inode(root), dentry); |
5955102c | 1952 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
1953 | |
1954 | d_delete(dentry); | |
1955 | ||
5955102c | 1956 | inode_unlock(d_inode(root)); |
7063fbf2 JB |
1957 | |
1958 | dput(dentry); | |
1959 | ||
1960 | unlink_group(group); | |
1961 | configfs_release_fs(); | |
1962 | } | |
1963 | ||
1964 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1965 | EXPORT_SYMBOL(configfs_unregister_subsystem); |