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 | 36 | |
84ec758f C |
37 | /* |
38 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
39 | * subsys->su_mutex is held. | |
40 | * But parent configfs_subsystem is NULL when config_item is root. | |
41 | * Use this mutex when config_item is root. | |
42 | */ | |
43 | static DEFINE_MUTEX(configfs_subsystem_mutex); | |
44 | ||
7063fbf2 JB |
45 | static void configfs_d_iput(struct dentry * dentry, |
46 | struct inode * inode) | |
47 | { | |
24307aa1 | 48 | struct configfs_dirent *sd = dentry->d_fsdata; |
7063fbf2 JB |
49 | |
50 | if (sd) { | |
24307aa1 JB |
51 | /* Coordinate with configfs_readdir */ |
52 | spin_lock(&configfs_dirent_lock); | |
f6122ed2 ST |
53 | /* |
54 | * Set sd->s_dentry to null only when this dentry is the one | |
55 | * that is going to be killed. Otherwise configfs_d_iput may | |
d07f132a | 56 | * run just after configfs_lookup and set sd->s_dentry to |
f6122ed2 | 57 | * NULL even it's still in use. |
76ae281f | 58 | */ |
f6122ed2 | 59 | if (sd->s_dentry == dentry) |
76ae281f JB |
60 | sd->s_dentry = NULL; |
61 | ||
24307aa1 | 62 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
63 | configfs_put(sd); |
64 | } | |
65 | iput(inode); | |
66 | } | |
67 | ||
d463a0c4 | 68 | const struct dentry_operations configfs_dentry_ops = { |
7063fbf2 | 69 | .d_iput = configfs_d_iput, |
b26d4cd3 | 70 | .d_delete = always_delete_dentry, |
7063fbf2 JB |
71 | }; |
72 | ||
e74cc06d LR |
73 | #ifdef CONFIG_LOCKDEP |
74 | ||
75 | /* | |
76 | * Helpers to make lockdep happy with our recursive locking of default groups' | |
77 | * inodes (see configfs_attach_group() and configfs_detach_group()). | |
78 | * We put default groups i_mutexes in separate classes according to their depth | |
79 | * from the youngest non-default group ancestor. | |
80 | * | |
81 | * For a non-default group A having default groups A/B, A/C, and A/C/D, default | |
82 | * groups A/B and A/C will have their inode's mutex in class | |
83 | * default_group_class[0], and default group A/C/D will be in | |
84 | * default_group_class[1]. | |
85 | * | |
86 | * The lock classes are declared and assigned in inode.c, according to the | |
87 | * s_depth value. | |
88 | * The s_depth value is initialized to -1, adjusted to >= 0 when attaching | |
89 | * default groups, and reset to -1 when all default groups are attached. During | |
90 | * attachment, if configfs_create() sees s_depth > 0, the lock class of the new | |
91 | * inode's mutex is set to default_group_class[s_depth - 1]. | |
92 | */ | |
93 | ||
94 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
95 | { | |
96 | sd->s_depth = -1; | |
97 | } | |
98 | ||
99 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
100 | struct configfs_dirent *sd) | |
101 | { | |
102 | int parent_depth = parent_sd->s_depth; | |
103 | ||
104 | if (parent_depth >= 0) | |
105 | sd->s_depth = parent_depth + 1; | |
106 | } | |
107 | ||
108 | static void | |
109 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
110 | { | |
111 | /* | |
112 | * item's i_mutex class is already setup, so s_depth is now only | |
113 | * used to set new sub-directories s_depth, which is always done | |
114 | * with item's i_mutex locked. | |
115 | */ | |
116 | /* | |
117 | * sd->s_depth == -1 iff we are a non default group. | |
118 | * else (we are a default group) sd->s_depth > 0 (see | |
119 | * create_dir()). | |
120 | */ | |
121 | if (sd->s_depth == -1) | |
122 | /* | |
123 | * We are a non default group and we are going to create | |
124 | * default groups. | |
125 | */ | |
126 | sd->s_depth = 0; | |
127 | } | |
128 | ||
129 | static void | |
130 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
131 | { | |
132 | /* We will not create default groups anymore. */ | |
133 | sd->s_depth = -1; | |
134 | } | |
135 | ||
136 | #else /* CONFIG_LOCKDEP */ | |
137 | ||
138 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
139 | { | |
140 | } | |
141 | ||
142 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
143 | struct configfs_dirent *sd) | |
144 | { | |
145 | } | |
146 | ||
147 | static void | |
148 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
149 | { | |
150 | } | |
151 | ||
152 | static void | |
153 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
154 | { | |
155 | } | |
156 | ||
157 | #endif /* CONFIG_LOCKDEP */ | |
158 | ||
47320fbe AV |
159 | static struct configfs_fragment *new_fragment(void) |
160 | { | |
161 | struct configfs_fragment *p; | |
162 | ||
163 | p = kmalloc(sizeof(struct configfs_fragment), GFP_KERNEL); | |
164 | if (p) { | |
165 | atomic_set(&p->frag_count, 1); | |
166 | init_rwsem(&p->frag_sem); | |
167 | p->frag_dead = false; | |
168 | } | |
169 | return p; | |
170 | } | |
171 | ||
172 | void put_fragment(struct configfs_fragment *frag) | |
173 | { | |
174 | if (frag && atomic_dec_and_test(&frag->frag_count)) | |
175 | kfree(frag); | |
176 | } | |
177 | ||
178 | struct configfs_fragment *get_fragment(struct configfs_fragment *frag) | |
179 | { | |
180 | if (likely(frag)) | |
181 | atomic_inc(&frag->frag_count); | |
182 | return frag; | |
183 | } | |
184 | ||
7063fbf2 JB |
185 | /* |
186 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
187 | */ | |
420118ca | 188 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
47320fbe AV |
189 | void *element, int type, |
190 | struct configfs_fragment *frag) | |
7063fbf2 JB |
191 | { |
192 | struct configfs_dirent * sd; | |
193 | ||
c3762229 | 194 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 195 | if (!sd) |
107ed40b | 196 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 197 | |
7063fbf2 | 198 | atomic_set(&sd->s_count, 1); |
7063fbf2 | 199 | INIT_LIST_HEAD(&sd->s_children); |
7063fbf2 | 200 | sd->s_element = element; |
420118ca | 201 | sd->s_type = type; |
e74cc06d | 202 | configfs_init_dirent_depth(sd); |
6f610764 | 203 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
204 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
205 | spin_unlock(&configfs_dirent_lock); | |
206 | kmem_cache_free(configfs_dir_cachep, sd); | |
207 | return ERR_PTR(-ENOENT); | |
208 | } | |
47320fbe | 209 | sd->s_frag = get_fragment(frag); |
6f610764 LR |
210 | list_add(&sd->s_sibling, &parent_sd->s_children); |
211 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
212 | |
213 | return sd; | |
214 | } | |
215 | ||
b4c98f62 JB |
216 | /* |
217 | * | |
218 | * Return -EEXIST if there is already a configfs element with the same | |
219 | * name for the same parent. | |
220 | * | |
221 | * called with parent inode's i_mutex held | |
222 | */ | |
58d206c2 AB |
223 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
224 | const unsigned char *new) | |
b4c98f62 JB |
225 | { |
226 | struct configfs_dirent * sd; | |
227 | ||
228 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
229 | if (sd->s_element) { | |
230 | const unsigned char *existing = configfs_get_name(sd); | |
231 | if (strcmp(existing, new)) | |
232 | continue; | |
233 | else | |
234 | return -EEXIST; | |
235 | } | |
236 | } | |
237 | ||
238 | return 0; | |
239 | } | |
240 | ||
241 | ||
7063fbf2 JB |
242 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
243 | struct dentry * dentry, void * element, | |
47320fbe | 244 | umode_t mode, int type, struct configfs_fragment *frag) |
7063fbf2 JB |
245 | { |
246 | struct configfs_dirent * sd; | |
247 | ||
47320fbe | 248 | sd = configfs_new_dirent(parent_sd, element, type, frag); |
107ed40b LR |
249 | if (IS_ERR(sd)) |
250 | return PTR_ERR(sd); | |
7063fbf2 JB |
251 | |
252 | sd->s_mode = mode; | |
7063fbf2 | 253 | sd->s_dentry = dentry; |
fbc8d4c0 | 254 | if (dentry) |
7063fbf2 | 255 | dentry->d_fsdata = configfs_get(sd); |
7063fbf2 JB |
256 | |
257 | return 0; | |
258 | } | |
259 | ||
1cf7a003 CH |
260 | static void configfs_remove_dirent(struct dentry *dentry) |
261 | { | |
262 | struct configfs_dirent *sd = dentry->d_fsdata; | |
263 | ||
264 | if (!sd) | |
265 | return; | |
266 | spin_lock(&configfs_dirent_lock); | |
267 | list_del_init(&sd->s_sibling); | |
268 | spin_unlock(&configfs_dirent_lock); | |
269 | configfs_put(sd); | |
270 | } | |
271 | ||
7063fbf2 JB |
272 | /** |
273 | * configfs_create_dir - create a directory for an config_item. | |
274 | * @item: config_itemwe're creating directory for. | |
275 | * @dentry: config_item's dentry. | |
65cdb4a2 | 276 | * @frag: config_item's fragment. |
2a109f2a LR |
277 | * |
278 | * Note: user-created entries won't be allowed under this new directory | |
279 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
280 | */ |
281 | ||
47320fbe AV |
282 | static int configfs_create_dir(struct config_item *item, struct dentry *dentry, |
283 | struct configfs_fragment *frag) | |
7063fbf2 | 284 | { |
1cf97d0d AV |
285 | int error; |
286 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
287 | struct dentry *p = dentry->d_parent; | |
2743c515 | 288 | struct inode *inode; |
1cf97d0d AV |
289 | |
290 | BUG_ON(!item); | |
291 | ||
292 | error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name); | |
293 | if (unlikely(error)) | |
294 | return error; | |
295 | ||
296 | error = configfs_make_dirent(p->d_fsdata, dentry, item, mode, | |
47320fbe AV |
297 | CONFIGFS_DIR | CONFIGFS_USET_CREATING, |
298 | frag); | |
1cf97d0d AV |
299 | if (unlikely(error)) |
300 | return error; | |
301 | ||
302 | configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata); | |
2743c515 AV |
303 | inode = configfs_create(dentry, mode); |
304 | if (IS_ERR(inode)) | |
1cf7a003 CH |
305 | goto out_remove; |
306 | ||
2743c515 AV |
307 | inode->i_op = &configfs_dir_inode_operations; |
308 | inode->i_fop = &configfs_dir_operations; | |
309 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
310 | inc_nlink(inode); | |
311 | d_instantiate(dentry, inode); | |
312 | /* already hashed */ | |
313 | dget(dentry); /* pin directory dentries in core */ | |
1cf7a003 CH |
314 | inc_nlink(d_inode(p)); |
315 | item->ci_dentry = dentry; | |
316 | return 0; | |
317 | ||
318 | out_remove: | |
c65234b2 | 319 | configfs_put(dentry->d_fsdata); |
1cf7a003 | 320 | configfs_remove_dirent(dentry); |
2743c515 | 321 | return PTR_ERR(inode); |
7063fbf2 JB |
322 | } |
323 | ||
2a109f2a LR |
324 | /* |
325 | * Allow userspace to create new entries under a new directory created with | |
326 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
327 | * @sd configfs_dirent of the new directory to validate | |
328 | * | |
329 | * Caller must hold configfs_dirent_lock. | |
330 | */ | |
331 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
332 | { | |
333 | struct configfs_dirent *child_sd; | |
334 | ||
335 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
336 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
337 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
338 | configfs_dir_set_ready(child_sd); | |
339 | } | |
340 | ||
341 | /* | |
342 | * Check that a directory does not belong to a directory hierarchy being | |
343 | * attached and not validated yet. | |
344 | * @sd configfs_dirent of the directory to check | |
345 | * | |
346 | * @return non-zero iff the directory was validated | |
347 | * | |
348 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
349 | * in two consecutive calls, but never from true to false. | |
350 | */ | |
351 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
352 | { | |
353 | int ret; | |
354 | ||
355 | spin_lock(&configfs_dirent_lock); | |
356 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
357 | spin_unlock(&configfs_dirent_lock); | |
358 | ||
359 | return ret; | |
360 | } | |
361 | ||
e9c03af2 AV |
362 | int configfs_create_link(struct configfs_dirent *target, struct dentry *parent, |
363 | struct dentry *dentry, char *body) | |
7063fbf2 JB |
364 | { |
365 | int err = 0; | |
366 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
47320fbe | 367 | struct configfs_dirent *p = parent->d_fsdata; |
2743c515 | 368 | struct inode *inode; |
7063fbf2 | 369 | |
e9c03af2 AV |
370 | err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK, |
371 | p->s_frag); | |
1cf7a003 CH |
372 | if (err) |
373 | return err; | |
374 | ||
2743c515 AV |
375 | inode = configfs_create(dentry, mode); |
376 | if (IS_ERR(inode)) | |
1cf7a003 | 377 | goto out_remove; |
2743c515 | 378 | |
e9c03af2 | 379 | inode->i_link = body; |
2743c515 AV |
380 | inode->i_op = &configfs_symlink_inode_operations; |
381 | d_instantiate(dentry, inode); | |
382 | dget(dentry); /* pin link dentries in core */ | |
1cf7a003 CH |
383 | return 0; |
384 | ||
385 | out_remove: | |
c65234b2 | 386 | configfs_put(dentry->d_fsdata); |
1cf7a003 | 387 | configfs_remove_dirent(dentry); |
2743c515 | 388 | return PTR_ERR(inode); |
7063fbf2 JB |
389 | } |
390 | ||
391 | static void remove_dir(struct dentry * d) | |
392 | { | |
393 | struct dentry * parent = dget(d->d_parent); | |
7063fbf2 | 394 | |
1cf7a003 CH |
395 | configfs_remove_dirent(d); |
396 | ||
2b0143b5 DH |
397 | if (d_really_is_positive(d)) |
398 | simple_rmdir(d_inode(parent),d); | |
7063fbf2 | 399 | |
a455589f | 400 | pr_debug(" o %pd removing done (%d)\n", d, d_count(d)); |
7063fbf2 JB |
401 | |
402 | dput(parent); | |
403 | } | |
404 | ||
405 | /** | |
406 | * configfs_remove_dir - remove an config_item's directory. | |
407 | * @item: config_item we're removing. | |
408 | * | |
409 | * The only thing special about this is that we remove any files in | |
410 | * the directory before we remove the directory, and we've inlined | |
411 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
412 | * |
413 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
414 | */ |
415 | ||
416 | static void configfs_remove_dir(struct config_item * item) | |
417 | { | |
418 | struct dentry * dentry = dget(item->ci_dentry); | |
419 | ||
420 | if (!dentry) | |
421 | return; | |
422 | ||
423 | remove_dir(dentry); | |
424 | /** | |
425 | * Drop reference from dget() on entrance. | |
426 | */ | |
427 | dput(dentry); | |
428 | } | |
429 | ||
7063fbf2 JB |
430 | static struct dentry * configfs_lookup(struct inode *dir, |
431 | struct dentry *dentry, | |
00cd8dd3 | 432 | unsigned int flags) |
7063fbf2 JB |
433 | { |
434 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
435 | struct configfs_dirent * sd; | |
d07f132a | 436 | struct inode *inode = NULL; |
2a109f2a | 437 | |
417b962d CH |
438 | if (dentry->d_name.len > NAME_MAX) |
439 | return ERR_PTR(-ENAMETOOLONG); | |
440 | ||
2a109f2a LR |
441 | /* |
442 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
443 | * being attached | |
444 | * | |
445 | * This forbids userspace to read/write attributes of items which may | |
446 | * not complete their initialization, since the dentries of the | |
447 | * attributes won't be instantiated. | |
448 | */ | |
2a109f2a | 449 | if (!configfs_dirent_is_ready(parent_sd)) |
899587c8 | 450 | return ERR_PTR(-ENOENT); |
7063fbf2 | 451 | |
c42dd069 | 452 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 453 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
d07f132a CH |
454 | if ((sd->s_type & CONFIGFS_NOT_PINNED) && |
455 | !strcmp(configfs_get_name(sd), dentry->d_name.name)) { | |
456 | struct configfs_attribute *attr = sd->s_element; | |
457 | umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG; | |
458 | ||
d07f132a CH |
459 | dentry->d_fsdata = configfs_get(sd); |
460 | sd->s_dentry = dentry; | |
461 | spin_unlock(&configfs_dirent_lock); | |
462 | ||
463 | inode = configfs_create(dentry, mode); | |
464 | if (IS_ERR(inode)) { | |
465 | configfs_put(sd); | |
466 | return ERR_CAST(inode); | |
467 | } | |
468 | if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) { | |
469 | inode->i_size = 0; | |
470 | inode->i_fop = &configfs_bin_file_operations; | |
471 | } else { | |
472 | inode->i_size = PAGE_SIZE; | |
473 | inode->i_fop = &configfs_file_operations; | |
474 | } | |
c42dd069 | 475 | goto done; |
7063fbf2 JB |
476 | } |
477 | } | |
c42dd069 SG |
478 | spin_unlock(&configfs_dirent_lock); |
479 | done: | |
d07f132a CH |
480 | d_add(dentry, inode); |
481 | return NULL; | |
7063fbf2 JB |
482 | } |
483 | ||
484 | /* | |
485 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
486 | * attributes and are removed by rmdir(). We recurse, setting |
487 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
488 | * default detach. | |
489 | * If there is an error, the caller will reset the flags via | |
490 | * configfs_detach_rollback(). | |
7063fbf2 | 491 | */ |
48f35b7b | 492 | static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait) |
7063fbf2 JB |
493 | { |
494 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
495 | struct configfs_dirent *sd; | |
496 | int ret; | |
497 | ||
4768e9b1 LR |
498 | /* Mark that we're trying to drop the group */ |
499 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
500 | ||
7063fbf2 | 501 | ret = -EBUSY; |
e9c03af2 | 502 | if (parent_sd->s_links) |
7063fbf2 JB |
503 | goto out; |
504 | ||
505 | ret = 0; | |
506 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
507 | if (!sd->s_element || |
508 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
509 | continue; |
510 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
511 | /* Abort if racing with mkdir() */ |
512 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
48f35b7b AV |
513 | if (wait) |
514 | *wait= dget(sd->s_dentry); | |
6d8344ba LR |
515 | return -EAGAIN; |
516 | } | |
7063fbf2 | 517 | |
631d1feb JB |
518 | /* |
519 | * Yup, recursive. If there's a problem, blame | |
520 | * deep nesting of default_groups | |
521 | */ | |
48f35b7b | 522 | ret = configfs_detach_prep(sd->s_dentry, wait); |
7063fbf2 | 523 | if (!ret) |
e7515d06 | 524 | continue; |
7063fbf2 JB |
525 | } else |
526 | ret = -ENOTEMPTY; | |
527 | ||
528 | break; | |
529 | } | |
530 | ||
531 | out: | |
532 | return ret; | |
533 | } | |
534 | ||
535 | /* | |
b3e76af8 | 536 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
537 | * set. |
538 | */ | |
539 | static void configfs_detach_rollback(struct dentry *dentry) | |
540 | { | |
541 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
542 | struct configfs_dirent *sd; | |
543 | ||
4768e9b1 LR |
544 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
545 | ||
546 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
547 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 548 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
549 | } |
550 | ||
551 | static void detach_attrs(struct config_item * item) | |
552 | { | |
553 | struct dentry * dentry = dget(item->ci_dentry); | |
554 | struct configfs_dirent * parent_sd; | |
555 | struct configfs_dirent * sd, * tmp; | |
556 | ||
557 | if (!dentry) | |
558 | return; | |
559 | ||
560 | pr_debug("configfs %s: dropping attrs for dir\n", | |
561 | dentry->d_name.name); | |
562 | ||
563 | parent_sd = dentry->d_fsdata; | |
564 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
565 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
566 | continue; | |
6f610764 | 567 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 568 | list_del_init(&sd->s_sibling); |
6f610764 | 569 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
570 | configfs_drop_dentry(sd, dentry); |
571 | configfs_put(sd); | |
572 | } | |
573 | ||
574 | /** | |
575 | * Drop reference from dget() on entrance. | |
576 | */ | |
577 | dput(dentry); | |
578 | } | |
579 | ||
580 | static int populate_attrs(struct config_item *item) | |
581 | { | |
aa293583 | 582 | const struct config_item_type *t = item->ci_type; |
7063fbf2 | 583 | struct configfs_attribute *attr; |
03607ace | 584 | struct configfs_bin_attribute *bin_attr; |
7063fbf2 JB |
585 | int error = 0; |
586 | int i; | |
587 | ||
588 | if (!t) | |
589 | return -EINVAL; | |
590 | if (t->ct_attrs) { | |
591 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
592 | if ((error = configfs_create_file(item, attr))) | |
593 | break; | |
594 | } | |
595 | } | |
03607ace PA |
596 | if (t->ct_bin_attrs) { |
597 | for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) { | |
598 | error = configfs_create_bin_file(item, bin_attr); | |
599 | if (error) | |
600 | break; | |
601 | } | |
602 | } | |
7063fbf2 JB |
603 | |
604 | if (error) | |
605 | detach_attrs(item); | |
606 | ||
607 | return error; | |
608 | } | |
609 | ||
610 | static int configfs_attach_group(struct config_item *parent_item, | |
611 | struct config_item *item, | |
47320fbe AV |
612 | struct dentry *dentry, |
613 | struct configfs_fragment *frag); | |
7063fbf2 JB |
614 | static void configfs_detach_group(struct config_item *item); |
615 | ||
616 | static void detach_groups(struct config_group *group) | |
617 | { | |
618 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
619 | struct dentry *child; | |
620 | struct configfs_dirent *parent_sd; | |
621 | struct configfs_dirent *sd, *tmp; | |
622 | ||
623 | if (!dentry) | |
624 | return; | |
625 | ||
626 | parent_sd = dentry->d_fsdata; | |
627 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
628 | if (!sd->s_element || | |
629 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
630 | continue; | |
631 | ||
632 | child = sd->s_dentry; | |
633 | ||
5955102c | 634 | inode_lock(d_inode(child)); |
b3e76af8 | 635 | |
7063fbf2 | 636 | configfs_detach_group(sd->s_element); |
2b0143b5 | 637 | d_inode(child)->i_flags |= S_DEAD; |
d83c49f3 | 638 | dont_mount(child); |
7063fbf2 | 639 | |
5955102c | 640 | inode_unlock(d_inode(child)); |
7063fbf2 JB |
641 | |
642 | d_delete(child); | |
643 | dput(child); | |
644 | } | |
645 | ||
646 | /** | |
647 | * Drop reference from dget() on entrance. | |
648 | */ | |
649 | dput(dentry); | |
650 | } | |
651 | ||
652 | /* | |
653 | * This fakes mkdir(2) on a default_groups[] entry. It | |
654 | * creates a dentry, attachs it, and then does fixup | |
655 | * on the sd->s_type. | |
656 | * | |
657 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
658 | * try using vfs_mkdir. Just a thought. | |
659 | */ | |
660 | static int create_default_group(struct config_group *parent_group, | |
47320fbe AV |
661 | struct config_group *group, |
662 | struct configfs_fragment *frag) | |
7063fbf2 JB |
663 | { |
664 | int ret; | |
7063fbf2 JB |
665 | struct configfs_dirent *sd; |
666 | /* We trust the caller holds a reference to parent */ | |
667 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
668 | ||
669 | if (!group->cg_item.ci_name) | |
670 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
7063fbf2 JB |
671 | |
672 | ret = -ENOMEM; | |
ec193cf5 | 673 | child = d_alloc_name(parent, group->cg_item.ci_name); |
7063fbf2 JB |
674 | if (child) { |
675 | d_add(child, NULL); | |
676 | ||
677 | ret = configfs_attach_group(&parent_group->cg_item, | |
47320fbe | 678 | &group->cg_item, child, frag); |
7063fbf2 JB |
679 | if (!ret) { |
680 | sd = child->d_fsdata; | |
681 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
682 | } else { | |
2b0143b5 | 683 | BUG_ON(d_inode(child)); |
df7f9967 | 684 | d_drop(child); |
7063fbf2 JB |
685 | dput(child); |
686 | } | |
687 | } | |
688 | ||
689 | return ret; | |
690 | } | |
691 | ||
47320fbe AV |
692 | static int populate_groups(struct config_group *group, |
693 | struct configfs_fragment *frag) | |
7063fbf2 JB |
694 | { |
695 | struct config_group *new_group; | |
7063fbf2 | 696 | int ret = 0; |
7063fbf2 | 697 | |
1ae1602d | 698 | list_for_each_entry(new_group, &group->default_groups, group_entry) { |
47320fbe | 699 | ret = create_default_group(group, new_group, frag); |
1ae1602d CH |
700 | if (ret) { |
701 | detach_groups(group); | |
702 | break; | |
7063fbf2 | 703 | } |
7063fbf2 JB |
704 | } |
705 | ||
7063fbf2 JB |
706 | return ret; |
707 | } | |
708 | ||
1ae1602d CH |
709 | void configfs_remove_default_groups(struct config_group *group) |
710 | { | |
711 | struct config_group *g, *n; | |
712 | ||
713 | list_for_each_entry_safe(g, n, &group->default_groups, group_entry) { | |
714 | list_del(&g->group_entry); | |
715 | config_item_put(&g->cg_item); | |
716 | } | |
717 | } | |
718 | EXPORT_SYMBOL(configfs_remove_default_groups); | |
719 | ||
7063fbf2 JB |
720 | /* |
721 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 722 | * subsys->su_mutex is held. |
7063fbf2 JB |
723 | */ |
724 | ||
725 | static void unlink_obj(struct config_item *item) | |
726 | { | |
727 | struct config_group *group; | |
728 | ||
729 | group = item->ci_group; | |
730 | if (group) { | |
731 | list_del_init(&item->ci_entry); | |
732 | ||
733 | item->ci_group = NULL; | |
734 | item->ci_parent = NULL; | |
eed7a0db JB |
735 | |
736 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
737 | config_item_put(item); |
738 | ||
eed7a0db | 739 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
740 | config_group_put(group); |
741 | } | |
742 | } | |
743 | ||
744 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
745 | { | |
eed7a0db JB |
746 | /* |
747 | * Parent seems redundant with group, but it makes certain | |
748 | * traversals much nicer. | |
749 | */ | |
7063fbf2 | 750 | item->ci_parent = parent_item; |
eed7a0db JB |
751 | |
752 | /* | |
753 | * We hold a reference on the parent for the child's ci_parent | |
754 | * link. | |
755 | */ | |
7063fbf2 JB |
756 | item->ci_group = config_group_get(to_config_group(parent_item)); |
757 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
758 | ||
eed7a0db JB |
759 | /* |
760 | * We hold a reference on the child for ci_entry on the parent's | |
761 | * cg_children | |
762 | */ | |
7063fbf2 JB |
763 | config_item_get(item); |
764 | } | |
765 | ||
766 | static void unlink_group(struct config_group *group) | |
767 | { | |
7063fbf2 JB |
768 | struct config_group *new_group; |
769 | ||
1ae1602d CH |
770 | list_for_each_entry(new_group, &group->default_groups, group_entry) |
771 | unlink_group(new_group); | |
7063fbf2 JB |
772 | |
773 | group->cg_subsys = NULL; | |
774 | unlink_obj(&group->cg_item); | |
775 | } | |
776 | ||
777 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
778 | { | |
7063fbf2 JB |
779 | struct config_group *new_group; |
780 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
781 | ||
782 | link_obj(&parent_group->cg_item, &group->cg_item); | |
783 | ||
784 | if (parent_group->cg_subsys) | |
785 | subsys = parent_group->cg_subsys; | |
786 | else if (configfs_is_root(&parent_group->cg_item)) | |
787 | subsys = to_configfs_subsystem(group); | |
788 | else | |
789 | BUG(); | |
790 | group->cg_subsys = subsys; | |
791 | ||
1ae1602d CH |
792 | list_for_each_entry(new_group, &group->default_groups, group_entry) |
793 | link_group(group, new_group); | |
7063fbf2 JB |
794 | } |
795 | ||
796 | /* | |
797 | * The goal is that configfs_attach_item() (and | |
798 | * configfs_attach_group()) can be called from either the VFS or this | |
799 | * module. That is, they assume that the items have been created, | |
800 | * the dentry allocated, and the dcache is all ready to go. | |
801 | * | |
802 | * If they fail, they must clean up after themselves as if they | |
803 | * had never been called. The caller (VFS or local function) will | |
804 | * handle cleaning up the dcache bits. | |
805 | * | |
806 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
807 | * the way out. They assume that the proper semaphores are held, they | |
808 | * clean up the configfs items, and they expect their callers will | |
809 | * handle the dcache bits. | |
810 | */ | |
811 | static int configfs_attach_item(struct config_item *parent_item, | |
812 | struct config_item *item, | |
47320fbe AV |
813 | struct dentry *dentry, |
814 | struct configfs_fragment *frag) | |
7063fbf2 JB |
815 | { |
816 | int ret; | |
817 | ||
47320fbe | 818 | ret = configfs_create_dir(item, dentry, frag); |
7063fbf2 JB |
819 | if (!ret) { |
820 | ret = populate_attrs(item); | |
821 | if (ret) { | |
2e2ce171 LR |
822 | /* |
823 | * We are going to remove an inode and its dentry but | |
824 | * the VFS may already have hit and used them. Thus, | |
825 | * we must lock them as rmdir() would. | |
826 | */ | |
5955102c | 827 | inode_lock(d_inode(dentry)); |
7063fbf2 | 828 | configfs_remove_dir(item); |
2b0143b5 | 829 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 830 | dont_mount(dentry); |
5955102c | 831 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
832 | d_delete(dentry); |
833 | } | |
834 | } | |
835 | ||
836 | return ret; | |
837 | } | |
838 | ||
2e2ce171 | 839 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
840 | static void configfs_detach_item(struct config_item *item) |
841 | { | |
842 | detach_attrs(item); | |
843 | configfs_remove_dir(item); | |
844 | } | |
845 | ||
846 | static int configfs_attach_group(struct config_item *parent_item, | |
847 | struct config_item *item, | |
47320fbe AV |
848 | struct dentry *dentry, |
849 | struct configfs_fragment *frag) | |
7063fbf2 JB |
850 | { |
851 | int ret; | |
852 | struct configfs_dirent *sd; | |
853 | ||
47320fbe | 854 | ret = configfs_attach_item(parent_item, item, dentry, frag); |
7063fbf2 JB |
855 | if (!ret) { |
856 | sd = dentry->d_fsdata; | |
857 | sd->s_type |= CONFIGFS_USET_DIR; | |
858 | ||
2e2ce171 LR |
859 | /* |
860 | * FYI, we're faking mkdir in populate_groups() | |
861 | * We must lock the group's inode to avoid races with the VFS | |
862 | * which can already hit the inode and try to add/remove entries | |
863 | * under it. | |
864 | * | |
865 | * We must also lock the inode to remove it safely in case of | |
866 | * error, as rmdir() would. | |
867 | */ | |
5955102c | 868 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
e74cc06d | 869 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
47320fbe | 870 | ret = populate_groups(to_config_group(item), frag); |
7063fbf2 JB |
871 | if (ret) { |
872 | configfs_detach_item(item); | |
2b0143b5 | 873 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 874 | dont_mount(dentry); |
7063fbf2 | 875 | } |
e74cc06d | 876 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
5955102c | 877 | inode_unlock(d_inode(dentry)); |
2e2ce171 LR |
878 | if (ret) |
879 | d_delete(dentry); | |
7063fbf2 JB |
880 | } |
881 | ||
882 | return ret; | |
883 | } | |
884 | ||
2e2ce171 | 885 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
886 | static void configfs_detach_group(struct config_item *item) |
887 | { | |
888 | detach_groups(to_config_group(item)); | |
889 | configfs_detach_item(item); | |
890 | } | |
891 | ||
299894cc JB |
892 | /* |
893 | * After the item has been detached from the filesystem view, we are | |
894 | * ready to tear it out of the hierarchy. Notify the client before | |
895 | * we do that so they can perform any cleanup that requires | |
896 | * navigating the hierarchy. A client does not need to provide this | |
897 | * callback. The subsystem semaphore MUST be held by the caller, and | |
898 | * references must be valid for both items. It also assumes the | |
899 | * caller has validated ci_type. | |
900 | */ | |
901 | static void client_disconnect_notify(struct config_item *parent_item, | |
902 | struct config_item *item) | |
903 | { | |
aa293583 | 904 | const struct config_item_type *type; |
299894cc JB |
905 | |
906 | type = parent_item->ci_type; | |
907 | BUG_ON(!type); | |
908 | ||
909 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
910 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
911 | item); | |
912 | } | |
913 | ||
7063fbf2 JB |
914 | /* |
915 | * Drop the initial reference from make_item()/make_group() | |
916 | * This function assumes that reference is held on item | |
917 | * and that item holds a valid reference to the parent. Also, it | |
918 | * assumes the caller has validated ci_type. | |
919 | */ | |
920 | static void client_drop_item(struct config_item *parent_item, | |
921 | struct config_item *item) | |
922 | { | |
aa293583 | 923 | const struct config_item_type *type; |
7063fbf2 JB |
924 | |
925 | type = parent_item->ci_type; | |
926 | BUG_ON(!type); | |
927 | ||
eed7a0db JB |
928 | /* |
929 | * If ->drop_item() exists, it is responsible for the | |
930 | * config_item_put(). | |
931 | */ | |
7063fbf2 JB |
932 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
933 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 934 | item); |
7063fbf2 JB |
935 | else |
936 | config_item_put(item); | |
937 | } | |
938 | ||
631d1feb JB |
939 | #ifdef DEBUG |
940 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
941 | { | |
c6686931 | 942 | pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
631d1feb | 943 | |
c6686931 | 944 | #define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type); |
631d1feb JB |
945 | type_print(CONFIGFS_ROOT); |
946 | type_print(CONFIGFS_DIR); | |
947 | type_print(CONFIGFS_ITEM_ATTR); | |
948 | type_print(CONFIGFS_ITEM_LINK); | |
949 | type_print(CONFIGFS_USET_DIR); | |
950 | type_print(CONFIGFS_USET_DEFAULT); | |
951 | type_print(CONFIGFS_USET_DROPPING); | |
952 | #undef type_print | |
953 | } | |
954 | ||
955 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
956 | { | |
957 | struct configfs_dirent *child_sd; | |
958 | int ret = 0; | |
959 | ||
960 | configfs_dump_one(sd, level); | |
961 | ||
962 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
963 | return 0; | |
964 | ||
965 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
966 | ret = configfs_dump(child_sd, level + 2); | |
967 | if (ret) | |
968 | break; | |
969 | } | |
970 | ||
971 | return ret; | |
972 | } | |
973 | #endif | |
974 | ||
975 | ||
976 | /* | |
977 | * configfs_depend_item() and configfs_undepend_item() | |
978 | * | |
979 | * WARNING: Do not call these from a configfs callback! | |
980 | * | |
981 | * This describes these functions and their helpers. | |
982 | * | |
983 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 984 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
985 | * it. The idea is to give client modules as simple an interface as |
986 | * possible. When a system asks them to depend on an item, they just | |
987 | * call configfs_depend_item(). If the item is live and the client | |
988 | * driver is in good shape, we'll happily do the work for them. | |
989 | * | |
990 | * Why is the locking complex? Because configfs uses the VFS to handle | |
991 | * all locking, but this function is called outside the normal | |
992 | * VFS->configfs path. So it must take VFS locks to prevent the | |
993 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
994 | * why you can't call these functions underneath configfs callbacks. | |
995 | * | |
996 | * Note, btw, that this can be called at *any* time, even when a configfs | |
997 | * subsystem isn't registered, or when configfs is loading or unloading. | |
998 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
999 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
1000 | * If we can find the target item in the | |
631d1feb | 1001 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
1002 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1003 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
1004 | */ |
1005 | ||
1006 | /* | |
1007 | * configfs_depend_prep() | |
1008 | * | |
1009 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1010 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1011 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1012 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1013 | * do that so we can unlock it if we find nothing. | |
1014 | * | |
1015 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1016 | * our object. |
1017 | * We deliberately ignore items tagged as dropping since they are virtually | |
1018 | * dead, as well as items in the middle of attachment since they virtually | |
1019 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1020 | * rmdir(). | |
1021 | * Note: subdirectories in the middle of attachment start with s_type = | |
1022 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1023 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1024 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1025 | * |
420118ca | 1026 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1027 | * |
1028 | * This adds a requirement that all config_items be unique! | |
1029 | * | |
420118ca | 1030 | * This is recursive. There isn't |
631d1feb JB |
1031 | * much on the stack, though, so folks that need this function - be careful |
1032 | * about your stack! Patches will be accepted to make it iterative. | |
1033 | */ | |
1034 | static int configfs_depend_prep(struct dentry *origin, | |
1035 | struct config_item *target) | |
1036 | { | |
49deb4bc | 1037 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1038 | int ret = 0; |
1039 | ||
49deb4bc WY |
1040 | BUG_ON(!origin || !origin->d_fsdata); |
1041 | sd = origin->d_fsdata; | |
631d1feb | 1042 | |
631d1feb JB |
1043 | if (sd->s_element == target) /* Boo-yah */ |
1044 | goto out; | |
1045 | ||
1046 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1047 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1048 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1049 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1050 | ret = configfs_depend_prep(child_sd->s_dentry, |
1051 | target); | |
1052 | if (!ret) | |
1053 | goto out; /* Child path boo-yah */ | |
1054 | } | |
1055 | } | |
1056 | ||
1057 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1058 | ret = -ENOENT; |
1059 | ||
1060 | out: | |
1061 | return ret; | |
1062 | } | |
1063 | ||
9fb434e7 KO |
1064 | static int configfs_do_depend_item(struct dentry *subsys_dentry, |
1065 | struct config_item *target) | |
1066 | { | |
1067 | struct configfs_dirent *p; | |
1068 | int ret; | |
1069 | ||
1070 | spin_lock(&configfs_dirent_lock); | |
1071 | /* Scan the tree, return 0 if found */ | |
1072 | ret = configfs_depend_prep(subsys_dentry, target); | |
1073 | if (ret) | |
1074 | goto out_unlock_dirent_lock; | |
1075 | ||
1076 | /* | |
1077 | * We are sure that the item is not about to be removed by rmdir(), and | |
1078 | * not in the middle of attachment by mkdir(). | |
1079 | */ | |
1080 | p = target->ci_dentry->d_fsdata; | |
1081 | p->s_dependent_count += 1; | |
1082 | ||
1083 | out_unlock_dirent_lock: | |
1084 | spin_unlock(&configfs_dirent_lock); | |
1085 | ||
1086 | return ret; | |
1087 | } | |
1088 | ||
9a70adff KO |
1089 | static inline struct configfs_dirent * |
1090 | configfs_find_subsys_dentry(struct configfs_dirent *root_sd, | |
1091 | struct config_item *subsys_item) | |
1092 | { | |
1093 | struct configfs_dirent *p; | |
1094 | struct configfs_dirent *ret = NULL; | |
1095 | ||
1096 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1097 | if (p->s_type & CONFIGFS_DIR && | |
1098 | p->s_element == subsys_item) { | |
1099 | ret = p; | |
1100 | break; | |
1101 | } | |
1102 | } | |
1103 | ||
1104 | return ret; | |
1105 | } | |
1106 | ||
1107 | ||
631d1feb JB |
1108 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1109 | struct config_item *target) | |
1110 | { | |
1111 | int ret; | |
9a70adff | 1112 | struct configfs_dirent *subsys_sd; |
631d1feb | 1113 | struct config_item *s_item = &subsys->su_group.cg_item; |
b7c177fc | 1114 | struct dentry *root; |
631d1feb JB |
1115 | |
1116 | /* | |
1117 | * Pin the configfs filesystem. This means we can safely access | |
1118 | * the root of the configfs filesystem. | |
1119 | */ | |
2a152ad3 AV |
1120 | root = configfs_pin_fs(); |
1121 | if (IS_ERR(root)) | |
1122 | return PTR_ERR(root); | |
631d1feb JB |
1123 | |
1124 | /* | |
1125 | * Next, lock the root directory. We're going to check that the | |
1126 | * subsystem is really registered, and so we need to lock out | |
1127 | * configfs_[un]register_subsystem(). | |
1128 | */ | |
5955102c | 1129 | inode_lock(d_inode(root)); |
631d1feb | 1130 | |
9a70adff | 1131 | subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item); |
631d1feb JB |
1132 | if (!subsys_sd) { |
1133 | ret = -ENOENT; | |
1134 | goto out_unlock_fs; | |
1135 | } | |
1136 | ||
1137 | /* Ok, now we can trust subsys/s_item */ | |
9fb434e7 | 1138 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); |
631d1feb | 1139 | |
631d1feb | 1140 | out_unlock_fs: |
5955102c | 1141 | inode_unlock(d_inode(root)); |
631d1feb JB |
1142 | |
1143 | /* | |
1144 | * If we succeeded, the fs is pinned via other methods. If not, | |
1145 | * we're done with it anyway. So release_fs() is always right. | |
1146 | */ | |
1147 | configfs_release_fs(); | |
1148 | ||
1149 | return ret; | |
1150 | } | |
1151 | EXPORT_SYMBOL(configfs_depend_item); | |
1152 | ||
1153 | /* | |
1154 | * Release the dependent linkage. This is much simpler than | |
ce9bebe6 | 1155 | * configfs_depend_item() because we know that the client driver is |
631d1feb JB |
1156 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. |
1157 | */ | |
9a9e3415 | 1158 | void configfs_undepend_item(struct config_item *target) |
631d1feb JB |
1159 | { |
1160 | struct configfs_dirent *sd; | |
1161 | ||
1162 | /* | |
420118ca LR |
1163 | * Since we can trust everything is pinned, we just need |
1164 | * configfs_dirent_lock. | |
631d1feb | 1165 | */ |
420118ca | 1166 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1167 | |
1168 | sd = target->ci_dentry->d_fsdata; | |
1169 | BUG_ON(sd->s_dependent_count < 1); | |
1170 | ||
1171 | sd->s_dependent_count -= 1; | |
1172 | ||
1173 | /* | |
1174 | * After this unlock, we cannot trust the item to stay alive! | |
1175 | * DO NOT REFERENCE item after this unlock. | |
1176 | */ | |
420118ca | 1177 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1178 | } |
1179 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1180 | |
d79d75b5 KO |
1181 | /* |
1182 | * caller_subsys is a caller's subsystem not target's. This is used to | |
1183 | * determine if we should lock root and check subsys or not. When we are | |
1184 | * in the same subsystem as our target there is no need to do locking as | |
1185 | * we know that subsys is valid and is not unregistered during this function | |
1186 | * as we are called from callback of one of his children and VFS holds a lock | |
1187 | * on some inode. Otherwise we have to lock our root to ensure that target's | |
1188 | * subsystem it is not unregistered during this function. | |
1189 | */ | |
1190 | int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, | |
1191 | struct config_item *target) | |
1192 | { | |
1193 | struct configfs_subsystem *target_subsys; | |
1194 | struct config_group *root, *parent; | |
1195 | struct configfs_dirent *subsys_sd; | |
1196 | int ret = -ENOENT; | |
1197 | ||
1198 | /* Disallow this function for configfs root */ | |
1199 | if (configfs_is_root(target)) | |
1200 | return -EINVAL; | |
1201 | ||
1202 | parent = target->ci_group; | |
1203 | /* | |
1204 | * This may happen when someone is trying to depend root | |
1205 | * directory of some subsystem | |
1206 | */ | |
1207 | if (configfs_is_root(&parent->cg_item)) { | |
1208 | target_subsys = to_configfs_subsystem(to_config_group(target)); | |
1209 | root = parent; | |
1210 | } else { | |
1211 | target_subsys = parent->cg_subsys; | |
1212 | /* Find a cofnigfs root as we may need it for locking */ | |
1213 | for (root = parent; !configfs_is_root(&root->cg_item); | |
1214 | root = root->cg_item.ci_group) | |
1215 | ; | |
1216 | } | |
1217 | ||
1218 | if (target_subsys != caller_subsys) { | |
1219 | /* | |
1220 | * We are in other configfs subsystem, so we have to do | |
1221 | * additional locking to prevent other subsystem from being | |
1222 | * unregistered | |
1223 | */ | |
5955102c | 1224 | inode_lock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1225 | |
1226 | /* | |
1227 | * As we are trying to depend item from other subsystem | |
1228 | * we have to check if this subsystem is still registered | |
1229 | */ | |
1230 | subsys_sd = configfs_find_subsys_dentry( | |
1231 | root->cg_item.ci_dentry->d_fsdata, | |
1232 | &target_subsys->su_group.cg_item); | |
1233 | if (!subsys_sd) | |
1234 | goto out_root_unlock; | |
1235 | } else { | |
1236 | subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata; | |
1237 | } | |
1238 | ||
1239 | /* Now we can execute core of depend item */ | |
1240 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); | |
1241 | ||
1242 | if (target_subsys != caller_subsys) | |
1243 | out_root_unlock: | |
1244 | /* | |
1245 | * We were called from subsystem other than our target so we | |
1246 | * took some locks so now it's time to release them | |
1247 | */ | |
5955102c | 1248 | inode_unlock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1249 | |
1250 | return ret; | |
1251 | } | |
1252 | EXPORT_SYMBOL(configfs_depend_item_unlocked); | |
1253 | ||
c54bd91e | 1254 | static int configfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, |
549c7297 | 1255 | struct dentry *dentry, umode_t mode) |
7063fbf2 | 1256 | { |
a6795e9e JB |
1257 | int ret = 0; |
1258 | int module_got = 0; | |
1259 | struct config_group *group = NULL; | |
1260 | struct config_item *item = NULL; | |
7063fbf2 JB |
1261 | struct config_item *parent_item; |
1262 | struct configfs_subsystem *subsys; | |
1263 | struct configfs_dirent *sd; | |
aa293583 | 1264 | const struct config_item_type *type; |
70526b67 | 1265 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
47320fbe | 1266 | struct configfs_fragment *frag; |
7063fbf2 JB |
1267 | char *name; |
1268 | ||
7063fbf2 | 1269 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1270 | |
1271 | /* | |
1272 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1273 | * being attached | |
1274 | */ | |
1275 | if (!configfs_dirent_is_ready(sd)) { | |
1276 | ret = -ENOENT; | |
1277 | goto out; | |
1278 | } | |
1279 | ||
84efad1a JB |
1280 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1281 | ret = -EPERM; | |
1282 | goto out; | |
1283 | } | |
7063fbf2 | 1284 | |
47320fbe AV |
1285 | frag = new_fragment(); |
1286 | if (!frag) { | |
1287 | ret = -ENOMEM; | |
1288 | goto out; | |
1289 | } | |
1290 | ||
84efad1a | 1291 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1292 | parent_item = configfs_get_config_item(dentry->d_parent); |
1293 | type = parent_item->ci_type; | |
1294 | subsys = to_config_group(parent_item)->cg_subsys; | |
1295 | BUG_ON(!subsys); | |
1296 | ||
1297 | if (!type || !type->ct_group_ops || | |
1298 | (!type->ct_group_ops->make_group && | |
1299 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1300 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1301 | goto out_put; | |
7063fbf2 JB |
1302 | } |
1303 | ||
70526b67 JB |
1304 | /* |
1305 | * The subsystem may belong to a different module than the item | |
1306 | * being created. We don't want to safely pin the new item but | |
1307 | * fail to pin the subsystem it sits under. | |
1308 | */ | |
1309 | if (!subsys->su_group.cg_item.ci_type) { | |
1310 | ret = -EINVAL; | |
1311 | goto out_put; | |
1312 | } | |
1313 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1314 | if (!try_module_get(subsys_owner)) { | |
1315 | ret = -EINVAL; | |
1316 | goto out_put; | |
1317 | } | |
1318 | ||
7063fbf2 JB |
1319 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1320 | if (!name) { | |
84efad1a | 1321 | ret = -ENOMEM; |
70526b67 | 1322 | goto out_subsys_put; |
7063fbf2 | 1323 | } |
84efad1a | 1324 | |
7063fbf2 JB |
1325 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1326 | ||
e6bd07ae | 1327 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1328 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1329 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1330 | if (!group) |
1331 | group = ERR_PTR(-ENOMEM); | |
1332 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1333 | link_group(to_config_group(parent_item), group); |
1334 | item = &group->cg_item; | |
a6795e9e JB |
1335 | } else |
1336 | ret = PTR_ERR(group); | |
7063fbf2 | 1337 | } else { |
f89ab861 | 1338 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1339 | if (!item) |
1340 | item = ERR_PTR(-ENOMEM); | |
1341 | if (!IS_ERR(item)) | |
7063fbf2 | 1342 | link_obj(parent_item, item); |
a6795e9e JB |
1343 | else |
1344 | ret = PTR_ERR(item); | |
7063fbf2 | 1345 | } |
e6bd07ae | 1346 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1347 | |
1348 | kfree(name); | |
a6795e9e | 1349 | if (ret) { |
eed7a0db | 1350 | /* |
dacdd0e0 | 1351 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1352 | * There are no extra references to clean up. |
1353 | */ | |
70526b67 | 1354 | goto out_subsys_put; |
7063fbf2 JB |
1355 | } |
1356 | ||
eed7a0db JB |
1357 | /* |
1358 | * link_obj() has been called (via link_group() for groups). | |
1359 | * From here on out, errors must clean that up. | |
1360 | */ | |
1361 | ||
7063fbf2 | 1362 | type = item->ci_type; |
eed7a0db JB |
1363 | if (!type) { |
1364 | ret = -EINVAL; | |
1365 | goto out_unlink; | |
1366 | } | |
7063fbf2 | 1367 | |
70526b67 JB |
1368 | new_item_owner = type->ct_owner; |
1369 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1370 | ret = -EINVAL; |
1371 | goto out_unlink; | |
1372 | } | |
7063fbf2 | 1373 | |
eed7a0db JB |
1374 | /* |
1375 | * I hate doing it this way, but if there is | |
1376 | * an error, module_put() probably should | |
1377 | * happen after any cleanup. | |
1378 | */ | |
1379 | module_got = 1; | |
1380 | ||
6d8344ba LR |
1381 | /* |
1382 | * Make racing rmdir() fail if it did not tag parent with | |
1383 | * CONFIGFS_USET_DROPPING | |
1384 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1385 | * fail and let rmdir() terminate correctly | |
1386 | */ | |
1387 | spin_lock(&configfs_dirent_lock); | |
1388 | /* This will make configfs_detach_prep() fail */ | |
1389 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1390 | spin_unlock(&configfs_dirent_lock); | |
1391 | ||
eed7a0db | 1392 | if (group) |
47320fbe | 1393 | ret = configfs_attach_group(parent_item, item, dentry, frag); |
eed7a0db | 1394 | else |
47320fbe | 1395 | ret = configfs_attach_item(parent_item, item, dentry, frag); |
eed7a0db | 1396 | |
6d8344ba LR |
1397 | spin_lock(&configfs_dirent_lock); |
1398 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1399 | if (!ret) |
1400 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1401 | spin_unlock(&configfs_dirent_lock); |
1402 | ||
eed7a0db JB |
1403 | out_unlink: |
1404 | if (ret) { | |
1405 | /* Tear down everything we built up */ | |
e6bd07ae | 1406 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1407 | |
1408 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1409 | if (group) |
1410 | unlink_group(group); | |
1411 | else | |
1412 | unlink_obj(item); | |
1413 | client_drop_item(parent_item, item); | |
299894cc | 1414 | |
e6bd07ae | 1415 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1416 | |
1417 | if (module_got) | |
70526b67 | 1418 | module_put(new_item_owner); |
7063fbf2 JB |
1419 | } |
1420 | ||
70526b67 JB |
1421 | out_subsys_put: |
1422 | if (ret) | |
1423 | module_put(subsys_owner); | |
1424 | ||
84efad1a JB |
1425 | out_put: |
1426 | /* | |
eed7a0db JB |
1427 | * link_obj()/link_group() took a reference from child->parent, |
1428 | * so the parent is safely pinned. We can drop our working | |
1429 | * reference. | |
84efad1a JB |
1430 | */ |
1431 | config_item_put(parent_item); | |
47320fbe | 1432 | put_fragment(frag); |
84efad1a JB |
1433 | |
1434 | out: | |
7063fbf2 JB |
1435 | return ret; |
1436 | } | |
1437 | ||
1438 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1439 | { | |
1440 | struct config_item *parent_item; | |
1441 | struct config_item *item; | |
1442 | struct configfs_subsystem *subsys; | |
1443 | struct configfs_dirent *sd; | |
b0841eef | 1444 | struct configfs_fragment *frag; |
70526b67 | 1445 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1446 | int ret; |
1447 | ||
7063fbf2 JB |
1448 | sd = dentry->d_fsdata; |
1449 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1450 | return -EPERM; | |
1451 | ||
84efad1a | 1452 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1453 | parent_item = configfs_get_config_item(dentry->d_parent); |
1454 | subsys = to_config_group(parent_item)->cg_subsys; | |
1455 | BUG_ON(!subsys); | |
1456 | ||
1457 | if (!parent_item->ci_type) { | |
1458 | config_item_put(parent_item); | |
1459 | return -EINVAL; | |
1460 | } | |
1461 | ||
70526b67 JB |
1462 | /* configfs_mkdir() shouldn't have allowed this */ |
1463 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1464 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1465 | ||
9a73d78c LR |
1466 | /* |
1467 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1468 | * the new link is temporarily attached | |
1469 | */ | |
6d8344ba | 1470 | do { |
48f35b7b | 1471 | struct dentry *wait; |
6d8344ba | 1472 | |
de6bf18e LR |
1473 | mutex_lock(&configfs_symlink_mutex); |
1474 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1475 | /* |
1476 | * Here's where we check for dependents. We're protected by | |
1477 | * configfs_dirent_lock. | |
1478 | * If no dependent, atomically tag the item as dropping. | |
1479 | */ | |
1480 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1481 | if (!ret) { | |
48f35b7b | 1482 | ret = configfs_detach_prep(dentry, &wait); |
420118ca LR |
1483 | if (ret) |
1484 | configfs_detach_rollback(dentry); | |
1485 | } | |
de6bf18e LR |
1486 | spin_unlock(&configfs_dirent_lock); |
1487 | mutex_unlock(&configfs_symlink_mutex); | |
1488 | ||
1489 | if (ret) { | |
6d8344ba LR |
1490 | if (ret != -EAGAIN) { |
1491 | config_item_put(parent_item); | |
1492 | return ret; | |
1493 | } | |
1494 | ||
1495 | /* Wait until the racing operation terminates */ | |
48f35b7b AV |
1496 | inode_lock(d_inode(wait)); |
1497 | inode_unlock(d_inode(wait)); | |
1498 | dput(wait); | |
6d8344ba LR |
1499 | } |
1500 | } while (ret == -EAGAIN); | |
7063fbf2 | 1501 | |
b0841eef AV |
1502 | frag = sd->s_frag; |
1503 | if (down_write_killable(&frag->frag_sem)) { | |
1504 | spin_lock(&configfs_dirent_lock); | |
1505 | configfs_detach_rollback(dentry); | |
1506 | spin_unlock(&configfs_dirent_lock); | |
8aebfffa | 1507 | config_item_put(parent_item); |
b0841eef AV |
1508 | return -EINTR; |
1509 | } | |
1510 | frag->frag_dead = true; | |
1511 | up_write(&frag->frag_sem); | |
1512 | ||
84efad1a | 1513 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1514 | item = configfs_get_config_item(dentry); |
1515 | ||
1516 | /* Drop reference from above, item already holds one. */ | |
1517 | config_item_put(parent_item); | |
1518 | ||
1519 | if (item->ci_type) | |
70526b67 | 1520 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1521 | |
1522 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1523 | configfs_detach_group(item); | |
1524 | ||
e6bd07ae | 1525 | mutex_lock(&subsys->su_mutex); |
299894cc | 1526 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1527 | unlink_group(to_config_group(item)); |
1528 | } else { | |
1529 | configfs_detach_item(item); | |
1530 | ||
e6bd07ae | 1531 | mutex_lock(&subsys->su_mutex); |
299894cc | 1532 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1533 | unlink_obj(item); |
1534 | } | |
1535 | ||
1536 | client_drop_item(parent_item, item); | |
e6bd07ae | 1537 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1538 | |
1539 | /* Drop our reference from above */ | |
1540 | config_item_put(item); | |
1541 | ||
70526b67 JB |
1542 | module_put(dead_item_owner); |
1543 | module_put(subsys_owner); | |
7063fbf2 JB |
1544 | |
1545 | return 0; | |
1546 | } | |
1547 | ||
754661f1 | 1548 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1549 | .mkdir = configfs_mkdir, |
1550 | .rmdir = configfs_rmdir, | |
1551 | .symlink = configfs_symlink, | |
1552 | .unlink = configfs_unlink, | |
1553 | .lookup = configfs_lookup, | |
3d0f89bb | 1554 | .setattr = configfs_setattr, |
7063fbf2 JB |
1555 | }; |
1556 | ||
81d44ed1 AV |
1557 | const struct inode_operations configfs_root_inode_operations = { |
1558 | .lookup = configfs_lookup, | |
1559 | .setattr = configfs_setattr, | |
1560 | }; | |
1561 | ||
7063fbf2 JB |
1562 | static int configfs_dir_open(struct inode *inode, struct file *file) |
1563 | { | |
867fa491 | 1564 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1565 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1566 | int err; |
7063fbf2 | 1567 | |
5955102c | 1568 | inode_lock(d_inode(dentry)); |
2a109f2a LR |
1569 | /* |
1570 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1571 | * being attached | |
1572 | */ | |
1573 | err = -ENOENT; | |
1574 | if (configfs_dirent_is_ready(parent_sd)) { | |
47320fbe | 1575 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0, NULL); |
2a109f2a LR |
1576 | if (IS_ERR(file->private_data)) |
1577 | err = PTR_ERR(file->private_data); | |
1578 | else | |
1579 | err = 0; | |
1580 | } | |
5955102c | 1581 | inode_unlock(d_inode(dentry)); |
7063fbf2 | 1582 | |
2a109f2a | 1583 | return err; |
7063fbf2 JB |
1584 | } |
1585 | ||
1586 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1587 | { | |
867fa491 | 1588 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1589 | struct configfs_dirent * cursor = file->private_data; |
1590 | ||
5955102c | 1591 | inode_lock(d_inode(dentry)); |
6f610764 | 1592 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1593 | list_del_init(&cursor->s_sibling); |
6f610764 | 1594 | spin_unlock(&configfs_dirent_lock); |
5955102c | 1595 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
1596 | |
1597 | release_configfs_dirent(cursor); | |
1598 | ||
1599 | return 0; | |
1600 | } | |
1601 | ||
52018855 | 1602 | static int configfs_readdir(struct file *file, struct dir_context *ctx) |
7063fbf2 | 1603 | { |
52018855 | 1604 | struct dentry *dentry = file->f_path.dentry; |
b7c177fc | 1605 | struct super_block *sb = dentry->d_sb; |
7063fbf2 | 1606 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
52018855 | 1607 | struct configfs_dirent *cursor = file->private_data; |
7063fbf2 | 1608 | struct list_head *p, *q = &cursor->s_sibling; |
24307aa1 | 1609 | ino_t ino = 0; |
7063fbf2 | 1610 | |
52018855 AV |
1611 | if (!dir_emit_dots(file, ctx)) |
1612 | return 0; | |
a01b3007 AV |
1613 | spin_lock(&configfs_dirent_lock); |
1614 | if (ctx->pos == 2) | |
52018855 | 1615 | list_move(q, &parent_sd->s_children); |
52018855 AV |
1616 | for (p = q->next; p != &parent_sd->s_children; p = p->next) { |
1617 | struct configfs_dirent *next; | |
1618 | const char *name; | |
1619 | int len; | |
1620 | struct inode *inode = NULL; | |
1621 | ||
1622 | next = list_entry(p, struct configfs_dirent, s_sibling); | |
1623 | if (!next->s_element) | |
1624 | continue; | |
7063fbf2 | 1625 | |
52018855 AV |
1626 | /* |
1627 | * We'll have a dentry and an inode for | |
1628 | * PINNED items and for open attribute | |
1629 | * files. We lock here to prevent a race | |
1630 | * with configfs_d_iput() clearing | |
1631 | * s_dentry before calling iput(). | |
1632 | * | |
1633 | * Why do we go to the trouble? If | |
1634 | * someone has an attribute file open, | |
1635 | * the inode number should match until | |
1636 | * they close it. Beyond that, we don't | |
1637 | * care. | |
1638 | */ | |
52018855 AV |
1639 | dentry = next->s_dentry; |
1640 | if (dentry) | |
2b0143b5 | 1641 | inode = d_inode(dentry); |
52018855 AV |
1642 | if (inode) |
1643 | ino = inode->i_ino; | |
1644 | spin_unlock(&configfs_dirent_lock); | |
1645 | if (!inode) | |
1646 | ino = iunique(sb, 2); | |
7063fbf2 | 1647 | |
a01b3007 AV |
1648 | name = configfs_get_name(next); |
1649 | len = strlen(name); | |
1650 | ||
364595a6 JL |
1651 | if (!dir_emit(ctx, name, len, ino, |
1652 | fs_umode_to_dtype(next->s_mode))) | |
52018855 | 1653 | return 0; |
7063fbf2 | 1654 | |
52018855 AV |
1655 | spin_lock(&configfs_dirent_lock); |
1656 | list_move(q, p); | |
52018855 AV |
1657 | p = q; |
1658 | ctx->pos++; | |
7063fbf2 | 1659 | } |
a01b3007 | 1660 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1661 | return 0; |
1662 | } | |
1663 | ||
965c8e59 | 1664 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1665 | { |
867fa491 | 1666 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1667 | |
965c8e59 | 1668 | switch (whence) { |
7063fbf2 JB |
1669 | case 1: |
1670 | offset += file->f_pos; | |
df561f66 | 1671 | fallthrough; |
7063fbf2 JB |
1672 | case 0: |
1673 | if (offset >= 0) | |
1674 | break; | |
df561f66 | 1675 | fallthrough; |
7063fbf2 | 1676 | default: |
7063fbf2 JB |
1677 | return -EINVAL; |
1678 | } | |
1679 | if (offset != file->f_pos) { | |
1680 | file->f_pos = offset; | |
1681 | if (file->f_pos >= 2) { | |
1682 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1683 | struct configfs_dirent *cursor = file->private_data; | |
1684 | struct list_head *p; | |
1685 | loff_t n = file->f_pos - 2; | |
1686 | ||
6f610764 | 1687 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1688 | list_del(&cursor->s_sibling); |
1689 | p = sd->s_children.next; | |
1690 | while (n && p != &sd->s_children) { | |
1691 | struct configfs_dirent *next; | |
1692 | next = list_entry(p, struct configfs_dirent, | |
1693 | s_sibling); | |
1694 | if (next->s_element) | |
1695 | n--; | |
1696 | p = p->next; | |
1697 | } | |
1698 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1699 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1700 | } |
1701 | } | |
7063fbf2 JB |
1702 | return offset; |
1703 | } | |
1704 | ||
4b6f5d20 | 1705 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1706 | .open = configfs_dir_open, |
1707 | .release = configfs_dir_close, | |
1708 | .llseek = configfs_dir_lseek, | |
1709 | .read = generic_read_dir, | |
a01b3007 | 1710 | .iterate_shared = configfs_readdir, |
7063fbf2 JB |
1711 | }; |
1712 | ||
5cf6a51e DB |
1713 | /** |
1714 | * configfs_register_group - creates a parent-child relation between two groups | |
1715 | * @parent_group: parent group | |
1716 | * @group: child group | |
1717 | * | |
1718 | * link groups, creates dentry for the child and attaches it to the | |
1719 | * parent dentry. | |
1720 | * | |
1721 | * Return: 0 on success, negative errno code on error | |
1722 | */ | |
1723 | int configfs_register_group(struct config_group *parent_group, | |
1724 | struct config_group *group) | |
1725 | { | |
1726 | struct configfs_subsystem *subsys = parent_group->cg_subsys; | |
1727 | struct dentry *parent; | |
47320fbe | 1728 | struct configfs_fragment *frag; |
5cf6a51e DB |
1729 | int ret; |
1730 | ||
47320fbe AV |
1731 | frag = new_fragment(); |
1732 | if (!frag) | |
1733 | return -ENOMEM; | |
1734 | ||
5cf6a51e DB |
1735 | mutex_lock(&subsys->su_mutex); |
1736 | link_group(parent_group, group); | |
1737 | mutex_unlock(&subsys->su_mutex); | |
1738 | ||
1739 | parent = parent_group->cg_item.ci_dentry; | |
1740 | ||
5955102c | 1741 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
47320fbe | 1742 | ret = create_default_group(parent_group, group, frag); |
35399f87 Y |
1743 | if (ret) |
1744 | goto err_out; | |
1745 | ||
1746 | spin_lock(&configfs_dirent_lock); | |
1747 | configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); | |
1748 | spin_unlock(&configfs_dirent_lock); | |
1749 | inode_unlock(d_inode(parent)); | |
47320fbe | 1750 | put_fragment(frag); |
35399f87 Y |
1751 | return 0; |
1752 | err_out: | |
5955102c | 1753 | inode_unlock(d_inode(parent)); |
35399f87 Y |
1754 | mutex_lock(&subsys->su_mutex); |
1755 | unlink_group(group); | |
1756 | mutex_unlock(&subsys->su_mutex); | |
47320fbe | 1757 | put_fragment(frag); |
5cf6a51e DB |
1758 | return ret; |
1759 | } | |
1760 | EXPORT_SYMBOL(configfs_register_group); | |
1761 | ||
1762 | /** | |
1763 | * configfs_unregister_group() - unregisters a child group from its parent | |
1764 | * @group: parent group to be unregistered | |
1765 | * | |
1766 | * Undoes configfs_register_group() | |
1767 | */ | |
1768 | void configfs_unregister_group(struct config_group *group) | |
1769 | { | |
1770 | struct configfs_subsystem *subsys = group->cg_subsys; | |
1771 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1772 | struct dentry *parent = group->cg_item.ci_parent->ci_dentry; | |
b0841eef AV |
1773 | struct configfs_dirent *sd = dentry->d_fsdata; |
1774 | struct configfs_fragment *frag = sd->s_frag; | |
1775 | ||
1776 | down_write(&frag->frag_sem); | |
1777 | frag->frag_dead = true; | |
1778 | up_write(&frag->frag_sem); | |
5cf6a51e | 1779 | |
5955102c | 1780 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
5cf6a51e DB |
1781 | spin_lock(&configfs_dirent_lock); |
1782 | configfs_detach_prep(dentry, NULL); | |
1783 | spin_unlock(&configfs_dirent_lock); | |
1784 | ||
1785 | configfs_detach_group(&group->cg_item); | |
1786 | d_inode(dentry)->i_flags |= S_DEAD; | |
1787 | dont_mount(dentry); | |
29044dae | 1788 | d_drop(dentry); |
6146e78c | 1789 | fsnotify_rmdir(d_inode(parent), dentry); |
5955102c | 1790 | inode_unlock(d_inode(parent)); |
5cf6a51e DB |
1791 | |
1792 | dput(dentry); | |
1793 | ||
1794 | mutex_lock(&subsys->su_mutex); | |
1795 | unlink_group(group); | |
1796 | mutex_unlock(&subsys->su_mutex); | |
1797 | } | |
1798 | EXPORT_SYMBOL(configfs_unregister_group); | |
1799 | ||
1800 | /** | |
1801 | * configfs_register_default_group() - allocates and registers a child group | |
1802 | * @parent_group: parent group | |
1803 | * @name: child group name | |
1804 | * @item_type: child item type description | |
1805 | * | |
1806 | * boilerplate to allocate and register a child group with its parent. We need | |
1807 | * kzalloc'ed memory because child's default_group is initially empty. | |
1808 | * | |
1809 | * Return: allocated config group or ERR_PTR() on error | |
1810 | */ | |
1811 | struct config_group * | |
1812 | configfs_register_default_group(struct config_group *parent_group, | |
1813 | const char *name, | |
aa293583 | 1814 | const struct config_item_type *item_type) |
5cf6a51e DB |
1815 | { |
1816 | int ret; | |
1817 | struct config_group *group; | |
1818 | ||
1819 | group = kzalloc(sizeof(*group), GFP_KERNEL); | |
1820 | if (!group) | |
1821 | return ERR_PTR(-ENOMEM); | |
1822 | config_group_init_type_name(group, name, item_type); | |
1823 | ||
1824 | ret = configfs_register_group(parent_group, group); | |
1825 | if (ret) { | |
1826 | kfree(group); | |
1827 | return ERR_PTR(ret); | |
1828 | } | |
1829 | return group; | |
1830 | } | |
1831 | EXPORT_SYMBOL(configfs_register_default_group); | |
1832 | ||
1833 | /** | |
1834 | * configfs_unregister_default_group() - unregisters and frees a child group | |
1835 | * @group: the group to act on | |
1836 | */ | |
1837 | void configfs_unregister_default_group(struct config_group *group) | |
1838 | { | |
1839 | configfs_unregister_group(group); | |
1840 | kfree(group); | |
1841 | } | |
1842 | EXPORT_SYMBOL(configfs_unregister_default_group); | |
1843 | ||
7063fbf2 JB |
1844 | int configfs_register_subsystem(struct configfs_subsystem *subsys) |
1845 | { | |
1846 | int err; | |
1847 | struct config_group *group = &subsys->su_group; | |
7063fbf2 | 1848 | struct dentry *dentry; |
b7c177fc | 1849 | struct dentry *root; |
7063fbf2 | 1850 | struct configfs_dirent *sd; |
47320fbe AV |
1851 | struct configfs_fragment *frag; |
1852 | ||
1853 | frag = new_fragment(); | |
1854 | if (!frag) | |
1855 | return -ENOMEM; | |
7063fbf2 | 1856 | |
2a152ad3 | 1857 | root = configfs_pin_fs(); |
47320fbe AV |
1858 | if (IS_ERR(root)) { |
1859 | put_fragment(frag); | |
2a152ad3 | 1860 | return PTR_ERR(root); |
47320fbe | 1861 | } |
7063fbf2 JB |
1862 | |
1863 | if (!group->cg_item.ci_name) | |
1864 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1865 | ||
b7c177fc | 1866 | sd = root->d_fsdata; |
84ec758f | 1867 | mutex_lock(&configfs_subsystem_mutex); |
7063fbf2 | 1868 | link_group(to_config_group(sd->s_element), group); |
84ec758f | 1869 | mutex_unlock(&configfs_subsystem_mutex); |
7063fbf2 | 1870 | |
5955102c | 1871 | inode_lock_nested(d_inode(root), I_MUTEX_PARENT); |
7063fbf2 | 1872 | |
7063fbf2 | 1873 | err = -ENOMEM; |
ec193cf5 | 1874 | dentry = d_alloc_name(root, group->cg_item.ci_name); |
afdf04ea JB |
1875 | if (dentry) { |
1876 | d_add(dentry, NULL); | |
7063fbf2 | 1877 | |
afdf04ea | 1878 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
47320fbe | 1879 | dentry, frag); |
afdf04ea | 1880 | if (err) { |
2b0143b5 | 1881 | BUG_ON(d_inode(dentry)); |
df7f9967 | 1882 | d_drop(dentry); |
afdf04ea | 1883 | dput(dentry); |
2a109f2a LR |
1884 | } else { |
1885 | spin_lock(&configfs_dirent_lock); | |
1886 | configfs_dir_set_ready(dentry->d_fsdata); | |
1887 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1888 | } |
1889 | } | |
7063fbf2 | 1890 | |
5955102c | 1891 | inode_unlock(d_inode(root)); |
7063fbf2 | 1892 | |
afdf04ea | 1893 | if (err) { |
84ec758f | 1894 | mutex_lock(&configfs_subsystem_mutex); |
afdf04ea | 1895 | unlink_group(group); |
84ec758f | 1896 | mutex_unlock(&configfs_subsystem_mutex); |
afdf04ea | 1897 | configfs_release_fs(); |
7063fbf2 | 1898 | } |
47320fbe | 1899 | put_fragment(frag); |
7063fbf2 JB |
1900 | |
1901 | return err; | |
1902 | } | |
1903 | ||
1904 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1905 | { | |
1906 | struct config_group *group = &subsys->su_group; | |
1907 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1908 | struct dentry *root = dentry->d_sb->s_root; |
b0841eef AV |
1909 | struct configfs_dirent *sd = dentry->d_fsdata; |
1910 | struct configfs_fragment *frag = sd->s_frag; | |
7063fbf2 | 1911 | |
b7c177fc | 1912 | if (dentry->d_parent != root) { |
1d88aa44 | 1913 | pr_err("Tried to unregister non-subsystem!\n"); |
7063fbf2 JB |
1914 | return; |
1915 | } | |
1916 | ||
b0841eef AV |
1917 | down_write(&frag->frag_sem); |
1918 | frag->frag_dead = true; | |
1919 | up_write(&frag->frag_sem); | |
1920 | ||
5955102c | 1921 | inode_lock_nested(d_inode(root), |
55ed1602 | 1922 | I_MUTEX_PARENT); |
5955102c | 1923 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
9a73d78c | 1924 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1925 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1926 | if (configfs_detach_prep(dentry, NULL)) { |
1d88aa44 | 1927 | pr_err("Tried to unregister non-empty subsystem!\n"); |
7063fbf2 | 1928 | } |
b3e76af8 | 1929 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1930 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 | 1931 | configfs_detach_group(&group->cg_item); |
2b0143b5 | 1932 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 1933 | dont_mount(dentry); |
5955102c | 1934 | inode_unlock(d_inode(dentry)); |
7063fbf2 | 1935 | |
29044dae AG |
1936 | d_drop(dentry); |
1937 | fsnotify_rmdir(d_inode(root), dentry); | |
7063fbf2 | 1938 | |
5955102c | 1939 | inode_unlock(d_inode(root)); |
7063fbf2 JB |
1940 | |
1941 | dput(dentry); | |
1942 | ||
84ec758f | 1943 | mutex_lock(&configfs_subsystem_mutex); |
7063fbf2 | 1944 | unlink_group(group); |
84ec758f | 1945 | mutex_unlock(&configfs_subsystem_mutex); |
7063fbf2 JB |
1946 | configfs_release_fs(); |
1947 | } | |
1948 | ||
1949 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1950 | EXPORT_SYMBOL(configfs_unregister_subsystem); |