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 | |
d07f132a | 48 | * run just after configfs_lookup and set sd->s_dentry to |
f6122ed2 | 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 | ||
7063fbf2 JB |
420 | static struct dentry * configfs_lookup(struct inode *dir, |
421 | struct dentry *dentry, | |
00cd8dd3 | 422 | unsigned int flags) |
7063fbf2 JB |
423 | { |
424 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
425 | struct configfs_dirent * sd; | |
d07f132a | 426 | struct inode *inode = NULL; |
2a109f2a | 427 | |
417b962d CH |
428 | if (dentry->d_name.len > NAME_MAX) |
429 | return ERR_PTR(-ENAMETOOLONG); | |
430 | ||
2a109f2a LR |
431 | /* |
432 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
433 | * being attached | |
434 | * | |
435 | * This forbids userspace to read/write attributes of items which may | |
436 | * not complete their initialization, since the dentries of the | |
437 | * attributes won't be instantiated. | |
438 | */ | |
2a109f2a | 439 | if (!configfs_dirent_is_ready(parent_sd)) |
899587c8 | 440 | return ERR_PTR(-ENOENT); |
7063fbf2 | 441 | |
c42dd069 | 442 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 443 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
d07f132a CH |
444 | if ((sd->s_type & CONFIGFS_NOT_PINNED) && |
445 | !strcmp(configfs_get_name(sd), dentry->d_name.name)) { | |
446 | struct configfs_attribute *attr = sd->s_element; | |
447 | umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG; | |
448 | ||
d07f132a CH |
449 | dentry->d_fsdata = configfs_get(sd); |
450 | sd->s_dentry = dentry; | |
451 | spin_unlock(&configfs_dirent_lock); | |
452 | ||
453 | inode = configfs_create(dentry, mode); | |
454 | if (IS_ERR(inode)) { | |
455 | configfs_put(sd); | |
456 | return ERR_CAST(inode); | |
457 | } | |
458 | if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) { | |
459 | inode->i_size = 0; | |
460 | inode->i_fop = &configfs_bin_file_operations; | |
461 | } else { | |
462 | inode->i_size = PAGE_SIZE; | |
463 | inode->i_fop = &configfs_file_operations; | |
464 | } | |
c42dd069 | 465 | goto done; |
7063fbf2 JB |
466 | } |
467 | } | |
c42dd069 SG |
468 | spin_unlock(&configfs_dirent_lock); |
469 | done: | |
d07f132a CH |
470 | d_add(dentry, inode); |
471 | return NULL; | |
7063fbf2 JB |
472 | } |
473 | ||
474 | /* | |
475 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
476 | * attributes and are removed by rmdir(). We recurse, setting |
477 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
478 | * default detach. | |
479 | * If there is an error, the caller will reset the flags via | |
480 | * configfs_detach_rollback(). | |
7063fbf2 | 481 | */ |
48f35b7b | 482 | static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait) |
7063fbf2 JB |
483 | { |
484 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
485 | struct configfs_dirent *sd; | |
486 | int ret; | |
487 | ||
4768e9b1 LR |
488 | /* Mark that we're trying to drop the group */ |
489 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
490 | ||
7063fbf2 | 491 | ret = -EBUSY; |
e9c03af2 | 492 | if (parent_sd->s_links) |
7063fbf2 JB |
493 | goto out; |
494 | ||
495 | ret = 0; | |
496 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
497 | if (!sd->s_element || |
498 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
499 | continue; |
500 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
501 | /* Abort if racing with mkdir() */ |
502 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
48f35b7b AV |
503 | if (wait) |
504 | *wait= dget(sd->s_dentry); | |
6d8344ba LR |
505 | return -EAGAIN; |
506 | } | |
7063fbf2 | 507 | |
631d1feb JB |
508 | /* |
509 | * Yup, recursive. If there's a problem, blame | |
510 | * deep nesting of default_groups | |
511 | */ | |
48f35b7b | 512 | ret = configfs_detach_prep(sd->s_dentry, wait); |
7063fbf2 | 513 | if (!ret) |
e7515d06 | 514 | continue; |
7063fbf2 JB |
515 | } else |
516 | ret = -ENOTEMPTY; | |
517 | ||
518 | break; | |
519 | } | |
520 | ||
521 | out: | |
522 | return ret; | |
523 | } | |
524 | ||
525 | /* | |
b3e76af8 | 526 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
527 | * set. |
528 | */ | |
529 | static void configfs_detach_rollback(struct dentry *dentry) | |
530 | { | |
531 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
532 | struct configfs_dirent *sd; | |
533 | ||
4768e9b1 LR |
534 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
535 | ||
536 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
537 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 538 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
539 | } |
540 | ||
541 | static void detach_attrs(struct config_item * item) | |
542 | { | |
543 | struct dentry * dentry = dget(item->ci_dentry); | |
544 | struct configfs_dirent * parent_sd; | |
545 | struct configfs_dirent * sd, * tmp; | |
546 | ||
547 | if (!dentry) | |
548 | return; | |
549 | ||
550 | pr_debug("configfs %s: dropping attrs for dir\n", | |
551 | dentry->d_name.name); | |
552 | ||
553 | parent_sd = dentry->d_fsdata; | |
554 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
555 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
556 | continue; | |
6f610764 | 557 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 558 | list_del_init(&sd->s_sibling); |
6f610764 | 559 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
560 | configfs_drop_dentry(sd, dentry); |
561 | configfs_put(sd); | |
562 | } | |
563 | ||
564 | /** | |
565 | * Drop reference from dget() on entrance. | |
566 | */ | |
567 | dput(dentry); | |
568 | } | |
569 | ||
570 | static int populate_attrs(struct config_item *item) | |
571 | { | |
aa293583 | 572 | const struct config_item_type *t = item->ci_type; |
7063fbf2 | 573 | struct configfs_attribute *attr; |
03607ace | 574 | struct configfs_bin_attribute *bin_attr; |
7063fbf2 JB |
575 | int error = 0; |
576 | int i; | |
577 | ||
578 | if (!t) | |
579 | return -EINVAL; | |
580 | if (t->ct_attrs) { | |
581 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
582 | if ((error = configfs_create_file(item, attr))) | |
583 | break; | |
584 | } | |
585 | } | |
03607ace PA |
586 | if (t->ct_bin_attrs) { |
587 | for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) { | |
588 | error = configfs_create_bin_file(item, bin_attr); | |
589 | if (error) | |
590 | break; | |
591 | } | |
592 | } | |
7063fbf2 JB |
593 | |
594 | if (error) | |
595 | detach_attrs(item); | |
596 | ||
597 | return error; | |
598 | } | |
599 | ||
600 | static int configfs_attach_group(struct config_item *parent_item, | |
601 | struct config_item *item, | |
47320fbe AV |
602 | struct dentry *dentry, |
603 | struct configfs_fragment *frag); | |
7063fbf2 JB |
604 | static void configfs_detach_group(struct config_item *item); |
605 | ||
606 | static void detach_groups(struct config_group *group) | |
607 | { | |
608 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
609 | struct dentry *child; | |
610 | struct configfs_dirent *parent_sd; | |
611 | struct configfs_dirent *sd, *tmp; | |
612 | ||
613 | if (!dentry) | |
614 | return; | |
615 | ||
616 | parent_sd = dentry->d_fsdata; | |
617 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
618 | if (!sd->s_element || | |
619 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
620 | continue; | |
621 | ||
622 | child = sd->s_dentry; | |
623 | ||
5955102c | 624 | inode_lock(d_inode(child)); |
b3e76af8 | 625 | |
7063fbf2 | 626 | configfs_detach_group(sd->s_element); |
2b0143b5 | 627 | d_inode(child)->i_flags |= S_DEAD; |
d83c49f3 | 628 | dont_mount(child); |
7063fbf2 | 629 | |
5955102c | 630 | inode_unlock(d_inode(child)); |
7063fbf2 JB |
631 | |
632 | d_delete(child); | |
633 | dput(child); | |
634 | } | |
635 | ||
636 | /** | |
637 | * Drop reference from dget() on entrance. | |
638 | */ | |
639 | dput(dentry); | |
640 | } | |
641 | ||
642 | /* | |
643 | * This fakes mkdir(2) on a default_groups[] entry. It | |
644 | * creates a dentry, attachs it, and then does fixup | |
645 | * on the sd->s_type. | |
646 | * | |
647 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
648 | * try using vfs_mkdir. Just a thought. | |
649 | */ | |
650 | static int create_default_group(struct config_group *parent_group, | |
47320fbe AV |
651 | struct config_group *group, |
652 | struct configfs_fragment *frag) | |
7063fbf2 JB |
653 | { |
654 | int ret; | |
7063fbf2 JB |
655 | struct configfs_dirent *sd; |
656 | /* We trust the caller holds a reference to parent */ | |
657 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
658 | ||
659 | if (!group->cg_item.ci_name) | |
660 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
7063fbf2 JB |
661 | |
662 | ret = -ENOMEM; | |
ec193cf5 | 663 | child = d_alloc_name(parent, group->cg_item.ci_name); |
7063fbf2 JB |
664 | if (child) { |
665 | d_add(child, NULL); | |
666 | ||
667 | ret = configfs_attach_group(&parent_group->cg_item, | |
47320fbe | 668 | &group->cg_item, child, frag); |
7063fbf2 JB |
669 | if (!ret) { |
670 | sd = child->d_fsdata; | |
671 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
672 | } else { | |
2b0143b5 | 673 | BUG_ON(d_inode(child)); |
df7f9967 | 674 | d_drop(child); |
7063fbf2 JB |
675 | dput(child); |
676 | } | |
677 | } | |
678 | ||
679 | return ret; | |
680 | } | |
681 | ||
47320fbe AV |
682 | static int populate_groups(struct config_group *group, |
683 | struct configfs_fragment *frag) | |
7063fbf2 JB |
684 | { |
685 | struct config_group *new_group; | |
7063fbf2 | 686 | int ret = 0; |
7063fbf2 | 687 | |
1ae1602d | 688 | list_for_each_entry(new_group, &group->default_groups, group_entry) { |
47320fbe | 689 | ret = create_default_group(group, new_group, frag); |
1ae1602d CH |
690 | if (ret) { |
691 | detach_groups(group); | |
692 | break; | |
7063fbf2 | 693 | } |
7063fbf2 JB |
694 | } |
695 | ||
7063fbf2 JB |
696 | return ret; |
697 | } | |
698 | ||
1ae1602d CH |
699 | void configfs_remove_default_groups(struct config_group *group) |
700 | { | |
701 | struct config_group *g, *n; | |
702 | ||
703 | list_for_each_entry_safe(g, n, &group->default_groups, group_entry) { | |
704 | list_del(&g->group_entry); | |
705 | config_item_put(&g->cg_item); | |
706 | } | |
707 | } | |
708 | EXPORT_SYMBOL(configfs_remove_default_groups); | |
709 | ||
7063fbf2 JB |
710 | /* |
711 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 712 | * subsys->su_mutex is held. |
7063fbf2 JB |
713 | */ |
714 | ||
715 | static void unlink_obj(struct config_item *item) | |
716 | { | |
717 | struct config_group *group; | |
718 | ||
719 | group = item->ci_group; | |
720 | if (group) { | |
721 | list_del_init(&item->ci_entry); | |
722 | ||
723 | item->ci_group = NULL; | |
724 | item->ci_parent = NULL; | |
eed7a0db JB |
725 | |
726 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
727 | config_item_put(item); |
728 | ||
eed7a0db | 729 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
730 | config_group_put(group); |
731 | } | |
732 | } | |
733 | ||
734 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
735 | { | |
eed7a0db JB |
736 | /* |
737 | * Parent seems redundant with group, but it makes certain | |
738 | * traversals much nicer. | |
739 | */ | |
7063fbf2 | 740 | item->ci_parent = parent_item; |
eed7a0db JB |
741 | |
742 | /* | |
743 | * We hold a reference on the parent for the child's ci_parent | |
744 | * link. | |
745 | */ | |
7063fbf2 JB |
746 | item->ci_group = config_group_get(to_config_group(parent_item)); |
747 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
748 | ||
eed7a0db JB |
749 | /* |
750 | * We hold a reference on the child for ci_entry on the parent's | |
751 | * cg_children | |
752 | */ | |
7063fbf2 JB |
753 | config_item_get(item); |
754 | } | |
755 | ||
756 | static void unlink_group(struct config_group *group) | |
757 | { | |
7063fbf2 JB |
758 | struct config_group *new_group; |
759 | ||
1ae1602d CH |
760 | list_for_each_entry(new_group, &group->default_groups, group_entry) |
761 | unlink_group(new_group); | |
7063fbf2 JB |
762 | |
763 | group->cg_subsys = NULL; | |
764 | unlink_obj(&group->cg_item); | |
765 | } | |
766 | ||
767 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
768 | { | |
7063fbf2 JB |
769 | struct config_group *new_group; |
770 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
771 | ||
772 | link_obj(&parent_group->cg_item, &group->cg_item); | |
773 | ||
774 | if (parent_group->cg_subsys) | |
775 | subsys = parent_group->cg_subsys; | |
776 | else if (configfs_is_root(&parent_group->cg_item)) | |
777 | subsys = to_configfs_subsystem(group); | |
778 | else | |
779 | BUG(); | |
780 | group->cg_subsys = subsys; | |
781 | ||
1ae1602d CH |
782 | list_for_each_entry(new_group, &group->default_groups, group_entry) |
783 | link_group(group, new_group); | |
7063fbf2 JB |
784 | } |
785 | ||
786 | /* | |
787 | * The goal is that configfs_attach_item() (and | |
788 | * configfs_attach_group()) can be called from either the VFS or this | |
789 | * module. That is, they assume that the items have been created, | |
790 | * the dentry allocated, and the dcache is all ready to go. | |
791 | * | |
792 | * If they fail, they must clean up after themselves as if they | |
793 | * had never been called. The caller (VFS or local function) will | |
794 | * handle cleaning up the dcache bits. | |
795 | * | |
796 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
797 | * the way out. They assume that the proper semaphores are held, they | |
798 | * clean up the configfs items, and they expect their callers will | |
799 | * handle the dcache bits. | |
800 | */ | |
801 | static int configfs_attach_item(struct config_item *parent_item, | |
802 | struct config_item *item, | |
47320fbe AV |
803 | struct dentry *dentry, |
804 | struct configfs_fragment *frag) | |
7063fbf2 JB |
805 | { |
806 | int ret; | |
807 | ||
47320fbe | 808 | ret = configfs_create_dir(item, dentry, frag); |
7063fbf2 JB |
809 | if (!ret) { |
810 | ret = populate_attrs(item); | |
811 | if (ret) { | |
2e2ce171 LR |
812 | /* |
813 | * We are going to remove an inode and its dentry but | |
814 | * the VFS may already have hit and used them. Thus, | |
815 | * we must lock them as rmdir() would. | |
816 | */ | |
5955102c | 817 | inode_lock(d_inode(dentry)); |
7063fbf2 | 818 | configfs_remove_dir(item); |
2b0143b5 | 819 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 820 | dont_mount(dentry); |
5955102c | 821 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
822 | d_delete(dentry); |
823 | } | |
824 | } | |
825 | ||
826 | return ret; | |
827 | } | |
828 | ||
2e2ce171 | 829 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
830 | static void configfs_detach_item(struct config_item *item) |
831 | { | |
832 | detach_attrs(item); | |
833 | configfs_remove_dir(item); | |
834 | } | |
835 | ||
836 | static int configfs_attach_group(struct config_item *parent_item, | |
837 | struct config_item *item, | |
47320fbe AV |
838 | struct dentry *dentry, |
839 | struct configfs_fragment *frag) | |
7063fbf2 JB |
840 | { |
841 | int ret; | |
842 | struct configfs_dirent *sd; | |
843 | ||
47320fbe | 844 | ret = configfs_attach_item(parent_item, item, dentry, frag); |
7063fbf2 JB |
845 | if (!ret) { |
846 | sd = dentry->d_fsdata; | |
847 | sd->s_type |= CONFIGFS_USET_DIR; | |
848 | ||
2e2ce171 LR |
849 | /* |
850 | * FYI, we're faking mkdir in populate_groups() | |
851 | * We must lock the group's inode to avoid races with the VFS | |
852 | * which can already hit the inode and try to add/remove entries | |
853 | * under it. | |
854 | * | |
855 | * We must also lock the inode to remove it safely in case of | |
856 | * error, as rmdir() would. | |
857 | */ | |
5955102c | 858 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
e74cc06d | 859 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
47320fbe | 860 | ret = populate_groups(to_config_group(item), frag); |
7063fbf2 JB |
861 | if (ret) { |
862 | configfs_detach_item(item); | |
2b0143b5 | 863 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 864 | dont_mount(dentry); |
7063fbf2 | 865 | } |
e74cc06d | 866 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
5955102c | 867 | inode_unlock(d_inode(dentry)); |
2e2ce171 LR |
868 | if (ret) |
869 | d_delete(dentry); | |
7063fbf2 JB |
870 | } |
871 | ||
872 | return ret; | |
873 | } | |
874 | ||
2e2ce171 | 875 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
876 | static void configfs_detach_group(struct config_item *item) |
877 | { | |
878 | detach_groups(to_config_group(item)); | |
879 | configfs_detach_item(item); | |
880 | } | |
881 | ||
299894cc JB |
882 | /* |
883 | * After the item has been detached from the filesystem view, we are | |
884 | * ready to tear it out of the hierarchy. Notify the client before | |
885 | * we do that so they can perform any cleanup that requires | |
886 | * navigating the hierarchy. A client does not need to provide this | |
887 | * callback. The subsystem semaphore MUST be held by the caller, and | |
888 | * references must be valid for both items. It also assumes the | |
889 | * caller has validated ci_type. | |
890 | */ | |
891 | static void client_disconnect_notify(struct config_item *parent_item, | |
892 | struct config_item *item) | |
893 | { | |
aa293583 | 894 | const struct config_item_type *type; |
299894cc JB |
895 | |
896 | type = parent_item->ci_type; | |
897 | BUG_ON(!type); | |
898 | ||
899 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
900 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
901 | item); | |
902 | } | |
903 | ||
7063fbf2 JB |
904 | /* |
905 | * Drop the initial reference from make_item()/make_group() | |
906 | * This function assumes that reference is held on item | |
907 | * and that item holds a valid reference to the parent. Also, it | |
908 | * assumes the caller has validated ci_type. | |
909 | */ | |
910 | static void client_drop_item(struct config_item *parent_item, | |
911 | struct config_item *item) | |
912 | { | |
aa293583 | 913 | const struct config_item_type *type; |
7063fbf2 JB |
914 | |
915 | type = parent_item->ci_type; | |
916 | BUG_ON(!type); | |
917 | ||
eed7a0db JB |
918 | /* |
919 | * If ->drop_item() exists, it is responsible for the | |
920 | * config_item_put(). | |
921 | */ | |
7063fbf2 JB |
922 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
923 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 924 | item); |
7063fbf2 JB |
925 | else |
926 | config_item_put(item); | |
927 | } | |
928 | ||
631d1feb JB |
929 | #ifdef DEBUG |
930 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
931 | { | |
c6686931 | 932 | pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
631d1feb | 933 | |
c6686931 | 934 | #define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type); |
631d1feb JB |
935 | type_print(CONFIGFS_ROOT); |
936 | type_print(CONFIGFS_DIR); | |
937 | type_print(CONFIGFS_ITEM_ATTR); | |
938 | type_print(CONFIGFS_ITEM_LINK); | |
939 | type_print(CONFIGFS_USET_DIR); | |
940 | type_print(CONFIGFS_USET_DEFAULT); | |
941 | type_print(CONFIGFS_USET_DROPPING); | |
942 | #undef type_print | |
943 | } | |
944 | ||
945 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
946 | { | |
947 | struct configfs_dirent *child_sd; | |
948 | int ret = 0; | |
949 | ||
950 | configfs_dump_one(sd, level); | |
951 | ||
952 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
953 | return 0; | |
954 | ||
955 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
956 | ret = configfs_dump(child_sd, level + 2); | |
957 | if (ret) | |
958 | break; | |
959 | } | |
960 | ||
961 | return ret; | |
962 | } | |
963 | #endif | |
964 | ||
965 | ||
966 | /* | |
967 | * configfs_depend_item() and configfs_undepend_item() | |
968 | * | |
969 | * WARNING: Do not call these from a configfs callback! | |
970 | * | |
971 | * This describes these functions and their helpers. | |
972 | * | |
973 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 974 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
975 | * it. The idea is to give client modules as simple an interface as |
976 | * possible. When a system asks them to depend on an item, they just | |
977 | * call configfs_depend_item(). If the item is live and the client | |
978 | * driver is in good shape, we'll happily do the work for them. | |
979 | * | |
980 | * Why is the locking complex? Because configfs uses the VFS to handle | |
981 | * all locking, but this function is called outside the normal | |
982 | * VFS->configfs path. So it must take VFS locks to prevent the | |
983 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
984 | * why you can't call these functions underneath configfs callbacks. | |
985 | * | |
986 | * Note, btw, that this can be called at *any* time, even when a configfs | |
987 | * subsystem isn't registered, or when configfs is loading or unloading. | |
988 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
989 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
990 | * If we can find the target item in the | |
631d1feb | 991 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
992 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
993 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
994 | */ |
995 | ||
996 | /* | |
997 | * configfs_depend_prep() | |
998 | * | |
999 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1000 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1001 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1002 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1003 | * do that so we can unlock it if we find nothing. | |
1004 | * | |
1005 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1006 | * our object. |
1007 | * We deliberately ignore items tagged as dropping since they are virtually | |
1008 | * dead, as well as items in the middle of attachment since they virtually | |
1009 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1010 | * rmdir(). | |
1011 | * Note: subdirectories in the middle of attachment start with s_type = | |
1012 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1013 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1014 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1015 | * |
420118ca | 1016 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1017 | * |
1018 | * This adds a requirement that all config_items be unique! | |
1019 | * | |
420118ca | 1020 | * This is recursive. There isn't |
631d1feb JB |
1021 | * much on the stack, though, so folks that need this function - be careful |
1022 | * about your stack! Patches will be accepted to make it iterative. | |
1023 | */ | |
1024 | static int configfs_depend_prep(struct dentry *origin, | |
1025 | struct config_item *target) | |
1026 | { | |
49deb4bc | 1027 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1028 | int ret = 0; |
1029 | ||
49deb4bc WY |
1030 | BUG_ON(!origin || !origin->d_fsdata); |
1031 | sd = origin->d_fsdata; | |
631d1feb | 1032 | |
631d1feb JB |
1033 | if (sd->s_element == target) /* Boo-yah */ |
1034 | goto out; | |
1035 | ||
1036 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1037 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1038 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1039 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1040 | ret = configfs_depend_prep(child_sd->s_dentry, |
1041 | target); | |
1042 | if (!ret) | |
1043 | goto out; /* Child path boo-yah */ | |
1044 | } | |
1045 | } | |
1046 | ||
1047 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1048 | ret = -ENOENT; |
1049 | ||
1050 | out: | |
1051 | return ret; | |
1052 | } | |
1053 | ||
9fb434e7 KO |
1054 | static int configfs_do_depend_item(struct dentry *subsys_dentry, |
1055 | struct config_item *target) | |
1056 | { | |
1057 | struct configfs_dirent *p; | |
1058 | int ret; | |
1059 | ||
1060 | spin_lock(&configfs_dirent_lock); | |
1061 | /* Scan the tree, return 0 if found */ | |
1062 | ret = configfs_depend_prep(subsys_dentry, target); | |
1063 | if (ret) | |
1064 | goto out_unlock_dirent_lock; | |
1065 | ||
1066 | /* | |
1067 | * We are sure that the item is not about to be removed by rmdir(), and | |
1068 | * not in the middle of attachment by mkdir(). | |
1069 | */ | |
1070 | p = target->ci_dentry->d_fsdata; | |
1071 | p->s_dependent_count += 1; | |
1072 | ||
1073 | out_unlock_dirent_lock: | |
1074 | spin_unlock(&configfs_dirent_lock); | |
1075 | ||
1076 | return ret; | |
1077 | } | |
1078 | ||
9a70adff KO |
1079 | static inline struct configfs_dirent * |
1080 | configfs_find_subsys_dentry(struct configfs_dirent *root_sd, | |
1081 | struct config_item *subsys_item) | |
1082 | { | |
1083 | struct configfs_dirent *p; | |
1084 | struct configfs_dirent *ret = NULL; | |
1085 | ||
1086 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1087 | if (p->s_type & CONFIGFS_DIR && | |
1088 | p->s_element == subsys_item) { | |
1089 | ret = p; | |
1090 | break; | |
1091 | } | |
1092 | } | |
1093 | ||
1094 | return ret; | |
1095 | } | |
1096 | ||
1097 | ||
631d1feb JB |
1098 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1099 | struct config_item *target) | |
1100 | { | |
1101 | int ret; | |
9a70adff | 1102 | struct configfs_dirent *subsys_sd; |
631d1feb | 1103 | struct config_item *s_item = &subsys->su_group.cg_item; |
b7c177fc | 1104 | struct dentry *root; |
631d1feb JB |
1105 | |
1106 | /* | |
1107 | * Pin the configfs filesystem. This means we can safely access | |
1108 | * the root of the configfs filesystem. | |
1109 | */ | |
2a152ad3 AV |
1110 | root = configfs_pin_fs(); |
1111 | if (IS_ERR(root)) | |
1112 | return PTR_ERR(root); | |
631d1feb JB |
1113 | |
1114 | /* | |
1115 | * Next, lock the root directory. We're going to check that the | |
1116 | * subsystem is really registered, and so we need to lock out | |
1117 | * configfs_[un]register_subsystem(). | |
1118 | */ | |
5955102c | 1119 | inode_lock(d_inode(root)); |
631d1feb | 1120 | |
9a70adff | 1121 | subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item); |
631d1feb JB |
1122 | if (!subsys_sd) { |
1123 | ret = -ENOENT; | |
1124 | goto out_unlock_fs; | |
1125 | } | |
1126 | ||
1127 | /* Ok, now we can trust subsys/s_item */ | |
9fb434e7 | 1128 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); |
631d1feb | 1129 | |
631d1feb | 1130 | out_unlock_fs: |
5955102c | 1131 | inode_unlock(d_inode(root)); |
631d1feb JB |
1132 | |
1133 | /* | |
1134 | * If we succeeded, the fs is pinned via other methods. If not, | |
1135 | * we're done with it anyway. So release_fs() is always right. | |
1136 | */ | |
1137 | configfs_release_fs(); | |
1138 | ||
1139 | return ret; | |
1140 | } | |
1141 | EXPORT_SYMBOL(configfs_depend_item); | |
1142 | ||
1143 | /* | |
1144 | * Release the dependent linkage. This is much simpler than | |
ce9bebe6 | 1145 | * configfs_depend_item() because we know that the client driver is |
631d1feb JB |
1146 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. |
1147 | */ | |
9a9e3415 | 1148 | void configfs_undepend_item(struct config_item *target) |
631d1feb JB |
1149 | { |
1150 | struct configfs_dirent *sd; | |
1151 | ||
1152 | /* | |
420118ca LR |
1153 | * Since we can trust everything is pinned, we just need |
1154 | * configfs_dirent_lock. | |
631d1feb | 1155 | */ |
420118ca | 1156 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1157 | |
1158 | sd = target->ci_dentry->d_fsdata; | |
1159 | BUG_ON(sd->s_dependent_count < 1); | |
1160 | ||
1161 | sd->s_dependent_count -= 1; | |
1162 | ||
1163 | /* | |
1164 | * After this unlock, we cannot trust the item to stay alive! | |
1165 | * DO NOT REFERENCE item after this unlock. | |
1166 | */ | |
420118ca | 1167 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1168 | } |
1169 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1170 | |
d79d75b5 KO |
1171 | /* |
1172 | * caller_subsys is a caller's subsystem not target's. This is used to | |
1173 | * determine if we should lock root and check subsys or not. When we are | |
1174 | * in the same subsystem as our target there is no need to do locking as | |
1175 | * we know that subsys is valid and is not unregistered during this function | |
1176 | * as we are called from callback of one of his children and VFS holds a lock | |
1177 | * on some inode. Otherwise we have to lock our root to ensure that target's | |
1178 | * subsystem it is not unregistered during this function. | |
1179 | */ | |
1180 | int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, | |
1181 | struct config_item *target) | |
1182 | { | |
1183 | struct configfs_subsystem *target_subsys; | |
1184 | struct config_group *root, *parent; | |
1185 | struct configfs_dirent *subsys_sd; | |
1186 | int ret = -ENOENT; | |
1187 | ||
1188 | /* Disallow this function for configfs root */ | |
1189 | if (configfs_is_root(target)) | |
1190 | return -EINVAL; | |
1191 | ||
1192 | parent = target->ci_group; | |
1193 | /* | |
1194 | * This may happen when someone is trying to depend root | |
1195 | * directory of some subsystem | |
1196 | */ | |
1197 | if (configfs_is_root(&parent->cg_item)) { | |
1198 | target_subsys = to_configfs_subsystem(to_config_group(target)); | |
1199 | root = parent; | |
1200 | } else { | |
1201 | target_subsys = parent->cg_subsys; | |
1202 | /* Find a cofnigfs root as we may need it for locking */ | |
1203 | for (root = parent; !configfs_is_root(&root->cg_item); | |
1204 | root = root->cg_item.ci_group) | |
1205 | ; | |
1206 | } | |
1207 | ||
1208 | if (target_subsys != caller_subsys) { | |
1209 | /* | |
1210 | * We are in other configfs subsystem, so we have to do | |
1211 | * additional locking to prevent other subsystem from being | |
1212 | * unregistered | |
1213 | */ | |
5955102c | 1214 | inode_lock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1215 | |
1216 | /* | |
1217 | * As we are trying to depend item from other subsystem | |
1218 | * we have to check if this subsystem is still registered | |
1219 | */ | |
1220 | subsys_sd = configfs_find_subsys_dentry( | |
1221 | root->cg_item.ci_dentry->d_fsdata, | |
1222 | &target_subsys->su_group.cg_item); | |
1223 | if (!subsys_sd) | |
1224 | goto out_root_unlock; | |
1225 | } else { | |
1226 | subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata; | |
1227 | } | |
1228 | ||
1229 | /* Now we can execute core of depend item */ | |
1230 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); | |
1231 | ||
1232 | if (target_subsys != caller_subsys) | |
1233 | out_root_unlock: | |
1234 | /* | |
1235 | * We were called from subsystem other than our target so we | |
1236 | * took some locks so now it's time to release them | |
1237 | */ | |
5955102c | 1238 | inode_unlock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1239 | |
1240 | return ret; | |
1241 | } | |
1242 | EXPORT_SYMBOL(configfs_depend_item_unlocked); | |
1243 | ||
549c7297 CB |
1244 | static int configfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, |
1245 | struct dentry *dentry, umode_t mode) | |
7063fbf2 | 1246 | { |
a6795e9e JB |
1247 | int ret = 0; |
1248 | int module_got = 0; | |
1249 | struct config_group *group = NULL; | |
1250 | struct config_item *item = NULL; | |
7063fbf2 JB |
1251 | struct config_item *parent_item; |
1252 | struct configfs_subsystem *subsys; | |
1253 | struct configfs_dirent *sd; | |
aa293583 | 1254 | const struct config_item_type *type; |
70526b67 | 1255 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
47320fbe | 1256 | struct configfs_fragment *frag; |
7063fbf2 JB |
1257 | char *name; |
1258 | ||
7063fbf2 | 1259 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1260 | |
1261 | /* | |
1262 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1263 | * being attached | |
1264 | */ | |
1265 | if (!configfs_dirent_is_ready(sd)) { | |
1266 | ret = -ENOENT; | |
1267 | goto out; | |
1268 | } | |
1269 | ||
84efad1a JB |
1270 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1271 | ret = -EPERM; | |
1272 | goto out; | |
1273 | } | |
7063fbf2 | 1274 | |
47320fbe AV |
1275 | frag = new_fragment(); |
1276 | if (!frag) { | |
1277 | ret = -ENOMEM; | |
1278 | goto out; | |
1279 | } | |
1280 | ||
84efad1a | 1281 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1282 | parent_item = configfs_get_config_item(dentry->d_parent); |
1283 | type = parent_item->ci_type; | |
1284 | subsys = to_config_group(parent_item)->cg_subsys; | |
1285 | BUG_ON(!subsys); | |
1286 | ||
1287 | if (!type || !type->ct_group_ops || | |
1288 | (!type->ct_group_ops->make_group && | |
1289 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1290 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1291 | goto out_put; | |
7063fbf2 JB |
1292 | } |
1293 | ||
70526b67 JB |
1294 | /* |
1295 | * The subsystem may belong to a different module than the item | |
1296 | * being created. We don't want to safely pin the new item but | |
1297 | * fail to pin the subsystem it sits under. | |
1298 | */ | |
1299 | if (!subsys->su_group.cg_item.ci_type) { | |
1300 | ret = -EINVAL; | |
1301 | goto out_put; | |
1302 | } | |
1303 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1304 | if (!try_module_get(subsys_owner)) { | |
1305 | ret = -EINVAL; | |
1306 | goto out_put; | |
1307 | } | |
1308 | ||
7063fbf2 JB |
1309 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1310 | if (!name) { | |
84efad1a | 1311 | ret = -ENOMEM; |
70526b67 | 1312 | goto out_subsys_put; |
7063fbf2 | 1313 | } |
84efad1a | 1314 | |
7063fbf2 JB |
1315 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1316 | ||
e6bd07ae | 1317 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1318 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1319 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1320 | if (!group) |
1321 | group = ERR_PTR(-ENOMEM); | |
1322 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1323 | link_group(to_config_group(parent_item), group); |
1324 | item = &group->cg_item; | |
a6795e9e JB |
1325 | } else |
1326 | ret = PTR_ERR(group); | |
7063fbf2 | 1327 | } else { |
f89ab861 | 1328 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1329 | if (!item) |
1330 | item = ERR_PTR(-ENOMEM); | |
1331 | if (!IS_ERR(item)) | |
7063fbf2 | 1332 | link_obj(parent_item, item); |
a6795e9e JB |
1333 | else |
1334 | ret = PTR_ERR(item); | |
7063fbf2 | 1335 | } |
e6bd07ae | 1336 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1337 | |
1338 | kfree(name); | |
a6795e9e | 1339 | if (ret) { |
eed7a0db | 1340 | /* |
dacdd0e0 | 1341 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1342 | * There are no extra references to clean up. |
1343 | */ | |
70526b67 | 1344 | goto out_subsys_put; |
7063fbf2 JB |
1345 | } |
1346 | ||
eed7a0db JB |
1347 | /* |
1348 | * link_obj() has been called (via link_group() for groups). | |
1349 | * From here on out, errors must clean that up. | |
1350 | */ | |
1351 | ||
7063fbf2 | 1352 | type = item->ci_type; |
eed7a0db JB |
1353 | if (!type) { |
1354 | ret = -EINVAL; | |
1355 | goto out_unlink; | |
1356 | } | |
7063fbf2 | 1357 | |
70526b67 JB |
1358 | new_item_owner = type->ct_owner; |
1359 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1360 | ret = -EINVAL; |
1361 | goto out_unlink; | |
1362 | } | |
7063fbf2 | 1363 | |
eed7a0db JB |
1364 | /* |
1365 | * I hate doing it this way, but if there is | |
1366 | * an error, module_put() probably should | |
1367 | * happen after any cleanup. | |
1368 | */ | |
1369 | module_got = 1; | |
1370 | ||
6d8344ba LR |
1371 | /* |
1372 | * Make racing rmdir() fail if it did not tag parent with | |
1373 | * CONFIGFS_USET_DROPPING | |
1374 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1375 | * fail and let rmdir() terminate correctly | |
1376 | */ | |
1377 | spin_lock(&configfs_dirent_lock); | |
1378 | /* This will make configfs_detach_prep() fail */ | |
1379 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1380 | spin_unlock(&configfs_dirent_lock); | |
1381 | ||
eed7a0db | 1382 | if (group) |
47320fbe | 1383 | ret = configfs_attach_group(parent_item, item, dentry, frag); |
eed7a0db | 1384 | else |
47320fbe | 1385 | ret = configfs_attach_item(parent_item, item, dentry, frag); |
eed7a0db | 1386 | |
6d8344ba LR |
1387 | spin_lock(&configfs_dirent_lock); |
1388 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1389 | if (!ret) |
1390 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1391 | spin_unlock(&configfs_dirent_lock); |
1392 | ||
eed7a0db JB |
1393 | out_unlink: |
1394 | if (ret) { | |
1395 | /* Tear down everything we built up */ | |
e6bd07ae | 1396 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1397 | |
1398 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1399 | if (group) |
1400 | unlink_group(group); | |
1401 | else | |
1402 | unlink_obj(item); | |
1403 | client_drop_item(parent_item, item); | |
299894cc | 1404 | |
e6bd07ae | 1405 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1406 | |
1407 | if (module_got) | |
70526b67 | 1408 | module_put(new_item_owner); |
7063fbf2 JB |
1409 | } |
1410 | ||
70526b67 JB |
1411 | out_subsys_put: |
1412 | if (ret) | |
1413 | module_put(subsys_owner); | |
1414 | ||
84efad1a JB |
1415 | out_put: |
1416 | /* | |
eed7a0db JB |
1417 | * link_obj()/link_group() took a reference from child->parent, |
1418 | * so the parent is safely pinned. We can drop our working | |
1419 | * reference. | |
84efad1a JB |
1420 | */ |
1421 | config_item_put(parent_item); | |
47320fbe | 1422 | put_fragment(frag); |
84efad1a JB |
1423 | |
1424 | out: | |
7063fbf2 JB |
1425 | return ret; |
1426 | } | |
1427 | ||
1428 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1429 | { | |
1430 | struct config_item *parent_item; | |
1431 | struct config_item *item; | |
1432 | struct configfs_subsystem *subsys; | |
1433 | struct configfs_dirent *sd; | |
b0841eef | 1434 | struct configfs_fragment *frag; |
70526b67 | 1435 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1436 | int ret; |
1437 | ||
7063fbf2 JB |
1438 | sd = dentry->d_fsdata; |
1439 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1440 | return -EPERM; | |
1441 | ||
84efad1a | 1442 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1443 | parent_item = configfs_get_config_item(dentry->d_parent); |
1444 | subsys = to_config_group(parent_item)->cg_subsys; | |
1445 | BUG_ON(!subsys); | |
1446 | ||
1447 | if (!parent_item->ci_type) { | |
1448 | config_item_put(parent_item); | |
1449 | return -EINVAL; | |
1450 | } | |
1451 | ||
70526b67 JB |
1452 | /* configfs_mkdir() shouldn't have allowed this */ |
1453 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1454 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1455 | ||
9a73d78c LR |
1456 | /* |
1457 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1458 | * the new link is temporarily attached | |
1459 | */ | |
6d8344ba | 1460 | do { |
48f35b7b | 1461 | struct dentry *wait; |
6d8344ba | 1462 | |
de6bf18e LR |
1463 | mutex_lock(&configfs_symlink_mutex); |
1464 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1465 | /* |
1466 | * Here's where we check for dependents. We're protected by | |
1467 | * configfs_dirent_lock. | |
1468 | * If no dependent, atomically tag the item as dropping. | |
1469 | */ | |
1470 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1471 | if (!ret) { | |
48f35b7b | 1472 | ret = configfs_detach_prep(dentry, &wait); |
420118ca LR |
1473 | if (ret) |
1474 | configfs_detach_rollback(dentry); | |
1475 | } | |
de6bf18e LR |
1476 | spin_unlock(&configfs_dirent_lock); |
1477 | mutex_unlock(&configfs_symlink_mutex); | |
1478 | ||
1479 | if (ret) { | |
6d8344ba LR |
1480 | if (ret != -EAGAIN) { |
1481 | config_item_put(parent_item); | |
1482 | return ret; | |
1483 | } | |
1484 | ||
1485 | /* Wait until the racing operation terminates */ | |
48f35b7b AV |
1486 | inode_lock(d_inode(wait)); |
1487 | inode_unlock(d_inode(wait)); | |
1488 | dput(wait); | |
6d8344ba LR |
1489 | } |
1490 | } while (ret == -EAGAIN); | |
7063fbf2 | 1491 | |
b0841eef AV |
1492 | frag = sd->s_frag; |
1493 | if (down_write_killable(&frag->frag_sem)) { | |
1494 | spin_lock(&configfs_dirent_lock); | |
1495 | configfs_detach_rollback(dentry); | |
1496 | spin_unlock(&configfs_dirent_lock); | |
8aebfffa | 1497 | config_item_put(parent_item); |
b0841eef AV |
1498 | return -EINTR; |
1499 | } | |
1500 | frag->frag_dead = true; | |
1501 | up_write(&frag->frag_sem); | |
1502 | ||
84efad1a | 1503 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1504 | item = configfs_get_config_item(dentry); |
1505 | ||
1506 | /* Drop reference from above, item already holds one. */ | |
1507 | config_item_put(parent_item); | |
1508 | ||
1509 | if (item->ci_type) | |
70526b67 | 1510 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1511 | |
1512 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1513 | configfs_detach_group(item); | |
1514 | ||
e6bd07ae | 1515 | mutex_lock(&subsys->su_mutex); |
299894cc | 1516 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1517 | unlink_group(to_config_group(item)); |
1518 | } else { | |
1519 | configfs_detach_item(item); | |
1520 | ||
e6bd07ae | 1521 | mutex_lock(&subsys->su_mutex); |
299894cc | 1522 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1523 | unlink_obj(item); |
1524 | } | |
1525 | ||
1526 | client_drop_item(parent_item, item); | |
e6bd07ae | 1527 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1528 | |
1529 | /* Drop our reference from above */ | |
1530 | config_item_put(item); | |
1531 | ||
70526b67 JB |
1532 | module_put(dead_item_owner); |
1533 | module_put(subsys_owner); | |
7063fbf2 JB |
1534 | |
1535 | return 0; | |
1536 | } | |
1537 | ||
754661f1 | 1538 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1539 | .mkdir = configfs_mkdir, |
1540 | .rmdir = configfs_rmdir, | |
1541 | .symlink = configfs_symlink, | |
1542 | .unlink = configfs_unlink, | |
1543 | .lookup = configfs_lookup, | |
3d0f89bb | 1544 | .setattr = configfs_setattr, |
7063fbf2 JB |
1545 | }; |
1546 | ||
81d44ed1 AV |
1547 | const struct inode_operations configfs_root_inode_operations = { |
1548 | .lookup = configfs_lookup, | |
1549 | .setattr = configfs_setattr, | |
1550 | }; | |
1551 | ||
7063fbf2 JB |
1552 | static int configfs_dir_open(struct inode *inode, struct file *file) |
1553 | { | |
867fa491 | 1554 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1555 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1556 | int err; |
7063fbf2 | 1557 | |
5955102c | 1558 | inode_lock(d_inode(dentry)); |
2a109f2a LR |
1559 | /* |
1560 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1561 | * being attached | |
1562 | */ | |
1563 | err = -ENOENT; | |
1564 | if (configfs_dirent_is_ready(parent_sd)) { | |
47320fbe | 1565 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0, NULL); |
2a109f2a LR |
1566 | if (IS_ERR(file->private_data)) |
1567 | err = PTR_ERR(file->private_data); | |
1568 | else | |
1569 | err = 0; | |
1570 | } | |
5955102c | 1571 | inode_unlock(d_inode(dentry)); |
7063fbf2 | 1572 | |
2a109f2a | 1573 | return err; |
7063fbf2 JB |
1574 | } |
1575 | ||
1576 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1577 | { | |
867fa491 | 1578 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1579 | struct configfs_dirent * cursor = file->private_data; |
1580 | ||
5955102c | 1581 | inode_lock(d_inode(dentry)); |
6f610764 | 1582 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1583 | list_del_init(&cursor->s_sibling); |
6f610764 | 1584 | spin_unlock(&configfs_dirent_lock); |
5955102c | 1585 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
1586 | |
1587 | release_configfs_dirent(cursor); | |
1588 | ||
1589 | return 0; | |
1590 | } | |
1591 | ||
1592 | /* Relationship between s_mode and the DT_xxx types */ | |
1593 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1594 | { | |
1595 | return (sd->s_mode >> 12) & 15; | |
1596 | } | |
1597 | ||
52018855 | 1598 | static int configfs_readdir(struct file *file, struct dir_context *ctx) |
7063fbf2 | 1599 | { |
52018855 | 1600 | struct dentry *dentry = file->f_path.dentry; |
b7c177fc | 1601 | struct super_block *sb = dentry->d_sb; |
7063fbf2 | 1602 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
52018855 | 1603 | struct configfs_dirent *cursor = file->private_data; |
7063fbf2 | 1604 | struct list_head *p, *q = &cursor->s_sibling; |
24307aa1 | 1605 | ino_t ino = 0; |
7063fbf2 | 1606 | |
52018855 AV |
1607 | if (!dir_emit_dots(file, ctx)) |
1608 | return 0; | |
a01b3007 AV |
1609 | spin_lock(&configfs_dirent_lock); |
1610 | if (ctx->pos == 2) | |
52018855 | 1611 | list_move(q, &parent_sd->s_children); |
52018855 AV |
1612 | for (p = q->next; p != &parent_sd->s_children; p = p->next) { |
1613 | struct configfs_dirent *next; | |
1614 | const char *name; | |
1615 | int len; | |
1616 | struct inode *inode = NULL; | |
1617 | ||
1618 | next = list_entry(p, struct configfs_dirent, s_sibling); | |
1619 | if (!next->s_element) | |
1620 | continue; | |
7063fbf2 | 1621 | |
52018855 AV |
1622 | /* |
1623 | * We'll have a dentry and an inode for | |
1624 | * PINNED items and for open attribute | |
1625 | * files. We lock here to prevent a race | |
1626 | * with configfs_d_iput() clearing | |
1627 | * s_dentry before calling iput(). | |
1628 | * | |
1629 | * Why do we go to the trouble? If | |
1630 | * someone has an attribute file open, | |
1631 | * the inode number should match until | |
1632 | * they close it. Beyond that, we don't | |
1633 | * care. | |
1634 | */ | |
52018855 AV |
1635 | dentry = next->s_dentry; |
1636 | if (dentry) | |
2b0143b5 | 1637 | inode = d_inode(dentry); |
52018855 AV |
1638 | if (inode) |
1639 | ino = inode->i_ino; | |
1640 | spin_unlock(&configfs_dirent_lock); | |
1641 | if (!inode) | |
1642 | ino = iunique(sb, 2); | |
7063fbf2 | 1643 | |
a01b3007 AV |
1644 | name = configfs_get_name(next); |
1645 | len = strlen(name); | |
1646 | ||
52018855 AV |
1647 | if (!dir_emit(ctx, name, len, ino, dt_type(next))) |
1648 | return 0; | |
7063fbf2 | 1649 | |
52018855 AV |
1650 | spin_lock(&configfs_dirent_lock); |
1651 | list_move(q, p); | |
52018855 AV |
1652 | p = q; |
1653 | ctx->pos++; | |
7063fbf2 | 1654 | } |
a01b3007 | 1655 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1656 | return 0; |
1657 | } | |
1658 | ||
965c8e59 | 1659 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1660 | { |
867fa491 | 1661 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1662 | |
965c8e59 | 1663 | switch (whence) { |
7063fbf2 JB |
1664 | case 1: |
1665 | offset += file->f_pos; | |
df561f66 | 1666 | fallthrough; |
7063fbf2 JB |
1667 | case 0: |
1668 | if (offset >= 0) | |
1669 | break; | |
df561f66 | 1670 | fallthrough; |
7063fbf2 | 1671 | default: |
7063fbf2 JB |
1672 | return -EINVAL; |
1673 | } | |
1674 | if (offset != file->f_pos) { | |
1675 | file->f_pos = offset; | |
1676 | if (file->f_pos >= 2) { | |
1677 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1678 | struct configfs_dirent *cursor = file->private_data; | |
1679 | struct list_head *p; | |
1680 | loff_t n = file->f_pos - 2; | |
1681 | ||
6f610764 | 1682 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1683 | list_del(&cursor->s_sibling); |
1684 | p = sd->s_children.next; | |
1685 | while (n && p != &sd->s_children) { | |
1686 | struct configfs_dirent *next; | |
1687 | next = list_entry(p, struct configfs_dirent, | |
1688 | s_sibling); | |
1689 | if (next->s_element) | |
1690 | n--; | |
1691 | p = p->next; | |
1692 | } | |
1693 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1694 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1695 | } |
1696 | } | |
7063fbf2 JB |
1697 | return offset; |
1698 | } | |
1699 | ||
4b6f5d20 | 1700 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1701 | .open = configfs_dir_open, |
1702 | .release = configfs_dir_close, | |
1703 | .llseek = configfs_dir_lseek, | |
1704 | .read = generic_read_dir, | |
a01b3007 | 1705 | .iterate_shared = configfs_readdir, |
7063fbf2 JB |
1706 | }; |
1707 | ||
5cf6a51e DB |
1708 | /** |
1709 | * configfs_register_group - creates a parent-child relation between two groups | |
1710 | * @parent_group: parent group | |
1711 | * @group: child group | |
1712 | * | |
1713 | * link groups, creates dentry for the child and attaches it to the | |
1714 | * parent dentry. | |
1715 | * | |
1716 | * Return: 0 on success, negative errno code on error | |
1717 | */ | |
1718 | int configfs_register_group(struct config_group *parent_group, | |
1719 | struct config_group *group) | |
1720 | { | |
1721 | struct configfs_subsystem *subsys = parent_group->cg_subsys; | |
1722 | struct dentry *parent; | |
47320fbe | 1723 | struct configfs_fragment *frag; |
5cf6a51e DB |
1724 | int ret; |
1725 | ||
47320fbe AV |
1726 | frag = new_fragment(); |
1727 | if (!frag) | |
1728 | return -ENOMEM; | |
1729 | ||
5cf6a51e DB |
1730 | mutex_lock(&subsys->su_mutex); |
1731 | link_group(parent_group, group); | |
1732 | mutex_unlock(&subsys->su_mutex); | |
1733 | ||
1734 | parent = parent_group->cg_item.ci_dentry; | |
1735 | ||
5955102c | 1736 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
47320fbe | 1737 | ret = create_default_group(parent_group, group, frag); |
35399f87 Y |
1738 | if (ret) |
1739 | goto err_out; | |
1740 | ||
1741 | spin_lock(&configfs_dirent_lock); | |
1742 | configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); | |
1743 | spin_unlock(&configfs_dirent_lock); | |
1744 | inode_unlock(d_inode(parent)); | |
47320fbe | 1745 | put_fragment(frag); |
35399f87 Y |
1746 | return 0; |
1747 | err_out: | |
5955102c | 1748 | inode_unlock(d_inode(parent)); |
35399f87 Y |
1749 | mutex_lock(&subsys->su_mutex); |
1750 | unlink_group(group); | |
1751 | mutex_unlock(&subsys->su_mutex); | |
47320fbe | 1752 | put_fragment(frag); |
5cf6a51e DB |
1753 | return ret; |
1754 | } | |
1755 | EXPORT_SYMBOL(configfs_register_group); | |
1756 | ||
1757 | /** | |
1758 | * configfs_unregister_group() - unregisters a child group from its parent | |
1759 | * @group: parent group to be unregistered | |
1760 | * | |
1761 | * Undoes configfs_register_group() | |
1762 | */ | |
1763 | void configfs_unregister_group(struct config_group *group) | |
1764 | { | |
1765 | struct configfs_subsystem *subsys = group->cg_subsys; | |
1766 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1767 | struct dentry *parent = group->cg_item.ci_parent->ci_dentry; | |
b0841eef AV |
1768 | struct configfs_dirent *sd = dentry->d_fsdata; |
1769 | struct configfs_fragment *frag = sd->s_frag; | |
1770 | ||
1771 | down_write(&frag->frag_sem); | |
1772 | frag->frag_dead = true; | |
1773 | up_write(&frag->frag_sem); | |
5cf6a51e | 1774 | |
5955102c | 1775 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
5cf6a51e DB |
1776 | spin_lock(&configfs_dirent_lock); |
1777 | configfs_detach_prep(dentry, NULL); | |
1778 | spin_unlock(&configfs_dirent_lock); | |
1779 | ||
1780 | configfs_detach_group(&group->cg_item); | |
1781 | d_inode(dentry)->i_flags |= S_DEAD; | |
1782 | dont_mount(dentry); | |
6146e78c | 1783 | fsnotify_rmdir(d_inode(parent), dentry); |
5cf6a51e | 1784 | d_delete(dentry); |
5955102c | 1785 | inode_unlock(d_inode(parent)); |
5cf6a51e DB |
1786 | |
1787 | dput(dentry); | |
1788 | ||
1789 | mutex_lock(&subsys->su_mutex); | |
1790 | unlink_group(group); | |
1791 | mutex_unlock(&subsys->su_mutex); | |
1792 | } | |
1793 | EXPORT_SYMBOL(configfs_unregister_group); | |
1794 | ||
1795 | /** | |
1796 | * configfs_register_default_group() - allocates and registers a child group | |
1797 | * @parent_group: parent group | |
1798 | * @name: child group name | |
1799 | * @item_type: child item type description | |
1800 | * | |
1801 | * boilerplate to allocate and register a child group with its parent. We need | |
1802 | * kzalloc'ed memory because child's default_group is initially empty. | |
1803 | * | |
1804 | * Return: allocated config group or ERR_PTR() on error | |
1805 | */ | |
1806 | struct config_group * | |
1807 | configfs_register_default_group(struct config_group *parent_group, | |
1808 | const char *name, | |
aa293583 | 1809 | const struct config_item_type *item_type) |
5cf6a51e DB |
1810 | { |
1811 | int ret; | |
1812 | struct config_group *group; | |
1813 | ||
1814 | group = kzalloc(sizeof(*group), GFP_KERNEL); | |
1815 | if (!group) | |
1816 | return ERR_PTR(-ENOMEM); | |
1817 | config_group_init_type_name(group, name, item_type); | |
1818 | ||
1819 | ret = configfs_register_group(parent_group, group); | |
1820 | if (ret) { | |
1821 | kfree(group); | |
1822 | return ERR_PTR(ret); | |
1823 | } | |
1824 | return group; | |
1825 | } | |
1826 | EXPORT_SYMBOL(configfs_register_default_group); | |
1827 | ||
1828 | /** | |
1829 | * configfs_unregister_default_group() - unregisters and frees a child group | |
1830 | * @group: the group to act on | |
1831 | */ | |
1832 | void configfs_unregister_default_group(struct config_group *group) | |
1833 | { | |
1834 | configfs_unregister_group(group); | |
1835 | kfree(group); | |
1836 | } | |
1837 | EXPORT_SYMBOL(configfs_unregister_default_group); | |
1838 | ||
7063fbf2 JB |
1839 | int configfs_register_subsystem(struct configfs_subsystem *subsys) |
1840 | { | |
1841 | int err; | |
1842 | struct config_group *group = &subsys->su_group; | |
7063fbf2 | 1843 | struct dentry *dentry; |
b7c177fc | 1844 | struct dentry *root; |
7063fbf2 | 1845 | struct configfs_dirent *sd; |
47320fbe AV |
1846 | struct configfs_fragment *frag; |
1847 | ||
1848 | frag = new_fragment(); | |
1849 | if (!frag) | |
1850 | return -ENOMEM; | |
7063fbf2 | 1851 | |
2a152ad3 | 1852 | root = configfs_pin_fs(); |
47320fbe AV |
1853 | if (IS_ERR(root)) { |
1854 | put_fragment(frag); | |
2a152ad3 | 1855 | return PTR_ERR(root); |
47320fbe | 1856 | } |
7063fbf2 JB |
1857 | |
1858 | if (!group->cg_item.ci_name) | |
1859 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1860 | ||
b7c177fc | 1861 | sd = root->d_fsdata; |
7063fbf2 JB |
1862 | link_group(to_config_group(sd->s_element), group); |
1863 | ||
5955102c | 1864 | inode_lock_nested(d_inode(root), I_MUTEX_PARENT); |
7063fbf2 | 1865 | |
7063fbf2 | 1866 | err = -ENOMEM; |
ec193cf5 | 1867 | dentry = d_alloc_name(root, group->cg_item.ci_name); |
afdf04ea JB |
1868 | if (dentry) { |
1869 | d_add(dentry, NULL); | |
7063fbf2 | 1870 | |
afdf04ea | 1871 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
47320fbe | 1872 | dentry, frag); |
afdf04ea | 1873 | if (err) { |
2b0143b5 | 1874 | BUG_ON(d_inode(dentry)); |
df7f9967 | 1875 | d_drop(dentry); |
afdf04ea | 1876 | dput(dentry); |
2a109f2a LR |
1877 | } else { |
1878 | spin_lock(&configfs_dirent_lock); | |
1879 | configfs_dir_set_ready(dentry->d_fsdata); | |
1880 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1881 | } |
1882 | } | |
7063fbf2 | 1883 | |
5955102c | 1884 | inode_unlock(d_inode(root)); |
7063fbf2 | 1885 | |
afdf04ea JB |
1886 | if (err) { |
1887 | unlink_group(group); | |
1888 | configfs_release_fs(); | |
7063fbf2 | 1889 | } |
47320fbe | 1890 | put_fragment(frag); |
7063fbf2 JB |
1891 | |
1892 | return err; | |
1893 | } | |
1894 | ||
1895 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1896 | { | |
1897 | struct config_group *group = &subsys->su_group; | |
1898 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1899 | struct dentry *root = dentry->d_sb->s_root; |
b0841eef AV |
1900 | struct configfs_dirent *sd = dentry->d_fsdata; |
1901 | struct configfs_fragment *frag = sd->s_frag; | |
7063fbf2 | 1902 | |
b7c177fc | 1903 | if (dentry->d_parent != root) { |
1d88aa44 | 1904 | pr_err("Tried to unregister non-subsystem!\n"); |
7063fbf2 JB |
1905 | return; |
1906 | } | |
1907 | ||
b0841eef AV |
1908 | down_write(&frag->frag_sem); |
1909 | frag->frag_dead = true; | |
1910 | up_write(&frag->frag_sem); | |
1911 | ||
5955102c | 1912 | inode_lock_nested(d_inode(root), |
55ed1602 | 1913 | I_MUTEX_PARENT); |
5955102c | 1914 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
9a73d78c | 1915 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1916 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1917 | if (configfs_detach_prep(dentry, NULL)) { |
1d88aa44 | 1918 | pr_err("Tried to unregister non-empty subsystem!\n"); |
7063fbf2 | 1919 | } |
b3e76af8 | 1920 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1921 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 | 1922 | configfs_detach_group(&group->cg_item); |
2b0143b5 | 1923 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 1924 | dont_mount(dentry); |
6146e78c | 1925 | fsnotify_rmdir(d_inode(root), dentry); |
5955102c | 1926 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
1927 | |
1928 | d_delete(dentry); | |
1929 | ||
5955102c | 1930 | inode_unlock(d_inode(root)); |
7063fbf2 JB |
1931 | |
1932 | dput(dentry); | |
1933 | ||
1934 | unlink_group(group); | |
1935 | configfs_release_fs(); | |
1936 | } | |
1937 | ||
1938 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1939 | EXPORT_SYMBOL(configfs_unregister_subsystem); |