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7063fbf2 JB |
1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * dir.c - Operations for configfs directories. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public | |
17 | * License along with this program; if not, write to the | |
18 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | * Boston, MA 021110-1307, USA. | |
20 | * | |
21 | * Based on sysfs: | |
22 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
23 | * | |
24 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
25 | */ | |
26 | ||
27 | #undef DEBUG | |
28 | ||
29 | #include <linux/fs.h> | |
30 | #include <linux/mount.h> | |
31 | #include <linux/module.h> | |
32 | #include <linux/slab.h> | |
107ed40b | 33 | #include <linux/err.h> |
7063fbf2 JB |
34 | |
35 | #include <linux/configfs.h> | |
36 | #include "configfs_internal.h" | |
37 | ||
38 | DECLARE_RWSEM(configfs_rename_sem); | |
6f610764 LR |
39 | /* |
40 | * Protects mutations of configfs_dirent linkage together with proper i_mutex | |
5301a77d | 41 | * Also protects mutations of symlinks linkage to target configfs_dirent |
6f610764 LR |
42 | * Mutators of configfs_dirent linkage must *both* have the proper inode locked |
43 | * and configfs_dirent_lock locked, in that order. | |
5301a77d LR |
44 | * This allows one to safely traverse configfs_dirent trees and symlinks without |
45 | * having to lock inodes. | |
b3e76af8 LR |
46 | * |
47 | * Protects setting of CONFIGFS_USET_DROPPING: checking the flag | |
48 | * unlocked is not reliable unless in detach_groups() called from | |
49 | * rmdir()/unregister() and from configfs_attach_group() | |
6f610764 LR |
50 | */ |
51 | DEFINE_SPINLOCK(configfs_dirent_lock); | |
7063fbf2 JB |
52 | |
53 | static void configfs_d_iput(struct dentry * dentry, | |
54 | struct inode * inode) | |
55 | { | |
24307aa1 | 56 | struct configfs_dirent *sd = dentry->d_fsdata; |
7063fbf2 JB |
57 | |
58 | if (sd) { | |
24307aa1 JB |
59 | /* Coordinate with configfs_readdir */ |
60 | spin_lock(&configfs_dirent_lock); | |
e9fcebe0 ST |
61 | /* |
62 | * Set sd->s_dentry to null only when this dentry is the one | |
63 | * that is going to be killed. Otherwise configfs_d_iput may | |
64 | * run just after configfs_attach_attr and set sd->s_dentry to | |
65 | * NULL even it's still in use. | |
76ae281f | 66 | */ |
e9fcebe0 | 67 | if (sd->s_dentry == dentry) |
76ae281f JB |
68 | sd->s_dentry = NULL; |
69 | ||
24307aa1 | 70 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
71 | configfs_put(sd); |
72 | } | |
73 | iput(inode); | |
74 | } | |
75 | ||
d463a0c4 | 76 | const struct dentry_operations configfs_dentry_ops = { |
7063fbf2 | 77 | .d_iput = configfs_d_iput, |
b26d4cd3 | 78 | .d_delete = always_delete_dentry, |
7063fbf2 JB |
79 | }; |
80 | ||
e74cc06d LR |
81 | #ifdef CONFIG_LOCKDEP |
82 | ||
83 | /* | |
84 | * Helpers to make lockdep happy with our recursive locking of default groups' | |
85 | * inodes (see configfs_attach_group() and configfs_detach_group()). | |
86 | * We put default groups i_mutexes in separate classes according to their depth | |
87 | * from the youngest non-default group ancestor. | |
88 | * | |
89 | * For a non-default group A having default groups A/B, A/C, and A/C/D, default | |
90 | * groups A/B and A/C will have their inode's mutex in class | |
91 | * default_group_class[0], and default group A/C/D will be in | |
92 | * default_group_class[1]. | |
93 | * | |
94 | * The lock classes are declared and assigned in inode.c, according to the | |
95 | * s_depth value. | |
96 | * The s_depth value is initialized to -1, adjusted to >= 0 when attaching | |
97 | * default groups, and reset to -1 when all default groups are attached. During | |
98 | * attachment, if configfs_create() sees s_depth > 0, the lock class of the new | |
99 | * inode's mutex is set to default_group_class[s_depth - 1]. | |
100 | */ | |
101 | ||
102 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
103 | { | |
104 | sd->s_depth = -1; | |
105 | } | |
106 | ||
107 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
108 | struct configfs_dirent *sd) | |
109 | { | |
110 | int parent_depth = parent_sd->s_depth; | |
111 | ||
112 | if (parent_depth >= 0) | |
113 | sd->s_depth = parent_depth + 1; | |
114 | } | |
115 | ||
116 | static void | |
117 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
118 | { | |
119 | /* | |
120 | * item's i_mutex class is already setup, so s_depth is now only | |
121 | * used to set new sub-directories s_depth, which is always done | |
122 | * with item's i_mutex locked. | |
123 | */ | |
124 | /* | |
125 | * sd->s_depth == -1 iff we are a non default group. | |
126 | * else (we are a default group) sd->s_depth > 0 (see | |
127 | * create_dir()). | |
128 | */ | |
129 | if (sd->s_depth == -1) | |
130 | /* | |
131 | * We are a non default group and we are going to create | |
132 | * default groups. | |
133 | */ | |
134 | sd->s_depth = 0; | |
135 | } | |
136 | ||
137 | static void | |
138 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
139 | { | |
140 | /* We will not create default groups anymore. */ | |
141 | sd->s_depth = -1; | |
142 | } | |
143 | ||
144 | #else /* CONFIG_LOCKDEP */ | |
145 | ||
146 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
147 | { | |
148 | } | |
149 | ||
150 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
151 | struct configfs_dirent *sd) | |
152 | { | |
153 | } | |
154 | ||
155 | static void | |
156 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
157 | { | |
158 | } | |
159 | ||
160 | static void | |
161 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
162 | { | |
163 | } | |
164 | ||
165 | #endif /* CONFIG_LOCKDEP */ | |
166 | ||
7063fbf2 JB |
167 | /* |
168 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
169 | */ | |
420118ca LR |
170 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
171 | void *element, int type) | |
7063fbf2 JB |
172 | { |
173 | struct configfs_dirent * sd; | |
174 | ||
c3762229 | 175 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 176 | if (!sd) |
107ed40b | 177 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 178 | |
7063fbf2 JB |
179 | atomic_set(&sd->s_count, 1); |
180 | INIT_LIST_HEAD(&sd->s_links); | |
181 | INIT_LIST_HEAD(&sd->s_children); | |
7063fbf2 | 182 | sd->s_element = element; |
420118ca | 183 | sd->s_type = type; |
e74cc06d | 184 | configfs_init_dirent_depth(sd); |
6f610764 | 185 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
186 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
187 | spin_unlock(&configfs_dirent_lock); | |
188 | kmem_cache_free(configfs_dir_cachep, sd); | |
189 | return ERR_PTR(-ENOENT); | |
190 | } | |
6f610764 LR |
191 | list_add(&sd->s_sibling, &parent_sd->s_children); |
192 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
193 | |
194 | return sd; | |
195 | } | |
196 | ||
b4c98f62 JB |
197 | /* |
198 | * | |
199 | * Return -EEXIST if there is already a configfs element with the same | |
200 | * name for the same parent. | |
201 | * | |
202 | * called with parent inode's i_mutex held | |
203 | */ | |
58d206c2 AB |
204 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
205 | const unsigned char *new) | |
b4c98f62 JB |
206 | { |
207 | struct configfs_dirent * sd; | |
208 | ||
209 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
210 | if (sd->s_element) { | |
211 | const unsigned char *existing = configfs_get_name(sd); | |
212 | if (strcmp(existing, new)) | |
213 | continue; | |
214 | else | |
215 | return -EEXIST; | |
216 | } | |
217 | } | |
218 | ||
219 | return 0; | |
220 | } | |
221 | ||
222 | ||
7063fbf2 JB |
223 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
224 | struct dentry * dentry, void * element, | |
225 | umode_t mode, int type) | |
226 | { | |
227 | struct configfs_dirent * sd; | |
228 | ||
420118ca | 229 | sd = configfs_new_dirent(parent_sd, element, type); |
107ed40b LR |
230 | if (IS_ERR(sd)) |
231 | return PTR_ERR(sd); | |
7063fbf2 JB |
232 | |
233 | sd->s_mode = mode; | |
7063fbf2 | 234 | sd->s_dentry = dentry; |
fbc8d4c0 | 235 | if (dentry) |
7063fbf2 | 236 | dentry->d_fsdata = configfs_get(sd); |
7063fbf2 JB |
237 | |
238 | return 0; | |
239 | } | |
240 | ||
c88b1e70 | 241 | static void init_dir(struct inode * inode) |
7063fbf2 JB |
242 | { |
243 | inode->i_op = &configfs_dir_inode_operations; | |
244 | inode->i_fop = &configfs_dir_operations; | |
245 | ||
246 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 247 | inc_nlink(inode); |
7063fbf2 JB |
248 | } |
249 | ||
c88b1e70 | 250 | static void configfs_init_file(struct inode * inode) |
7063fbf2 JB |
251 | { |
252 | inode->i_size = PAGE_SIZE; | |
253 | inode->i_fop = &configfs_file_operations; | |
7063fbf2 JB |
254 | } |
255 | ||
03607ace PA |
256 | static void configfs_init_bin_file(struct inode *inode) |
257 | { | |
258 | inode->i_size = 0; | |
259 | inode->i_fop = &configfs_bin_file_operations; | |
260 | } | |
261 | ||
c88b1e70 | 262 | static void init_symlink(struct inode * inode) |
7063fbf2 JB |
263 | { |
264 | inode->i_op = &configfs_symlink_inode_operations; | |
7063fbf2 JB |
265 | } |
266 | ||
7063fbf2 JB |
267 | /** |
268 | * configfs_create_dir - create a directory for an config_item. | |
269 | * @item: config_itemwe're creating directory for. | |
270 | * @dentry: config_item's dentry. | |
2a109f2a LR |
271 | * |
272 | * Note: user-created entries won't be allowed under this new directory | |
273 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
274 | */ |
275 | ||
1cf97d0d | 276 | static int configfs_create_dir(struct config_item *item, struct dentry *dentry) |
7063fbf2 | 277 | { |
1cf97d0d AV |
278 | int error; |
279 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
280 | struct dentry *p = dentry->d_parent; | |
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, | |
289 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); | |
290 | if (unlikely(error)) | |
291 | return error; | |
292 | ||
293 | configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata); | |
294 | error = configfs_create(dentry, mode, init_dir); | |
295 | if (!error) { | |
2b0143b5 | 296 | inc_nlink(d_inode(p)); |
7063fbf2 | 297 | item->ci_dentry = dentry; |
1cf97d0d AV |
298 | } else { |
299 | struct configfs_dirent *sd = dentry->d_fsdata; | |
300 | if (sd) { | |
301 | spin_lock(&configfs_dirent_lock); | |
302 | list_del_init(&sd->s_sibling); | |
303 | spin_unlock(&configfs_dirent_lock); | |
304 | configfs_put(sd); | |
305 | } | |
306 | } | |
7063fbf2 JB |
307 | return error; |
308 | } | |
309 | ||
2a109f2a LR |
310 | /* |
311 | * Allow userspace to create new entries under a new directory created with | |
312 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
313 | * @sd configfs_dirent of the new directory to validate | |
314 | * | |
315 | * Caller must hold configfs_dirent_lock. | |
316 | */ | |
317 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
318 | { | |
319 | struct configfs_dirent *child_sd; | |
320 | ||
321 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
322 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
323 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
324 | configfs_dir_set_ready(child_sd); | |
325 | } | |
326 | ||
327 | /* | |
328 | * Check that a directory does not belong to a directory hierarchy being | |
329 | * attached and not validated yet. | |
330 | * @sd configfs_dirent of the directory to check | |
331 | * | |
332 | * @return non-zero iff the directory was validated | |
333 | * | |
334 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
335 | * in two consecutive calls, but never from true to false. | |
336 | */ | |
337 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
338 | { | |
339 | int ret; | |
340 | ||
341 | spin_lock(&configfs_dirent_lock); | |
342 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
343 | spin_unlock(&configfs_dirent_lock); | |
344 | ||
345 | return ret; | |
346 | } | |
347 | ||
7063fbf2 JB |
348 | int configfs_create_link(struct configfs_symlink *sl, |
349 | struct dentry *parent, | |
350 | struct dentry *dentry) | |
351 | { | |
352 | int err = 0; | |
353 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
354 | ||
3d0f89bb JB |
355 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
356 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 357 | if (!err) { |
3d0f89bb | 358 | err = configfs_create(dentry, mode, init_symlink); |
fbc8d4c0 | 359 | if (err) { |
3d0f89bb JB |
360 | struct configfs_dirent *sd = dentry->d_fsdata; |
361 | if (sd) { | |
6f610764 | 362 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 363 | list_del_init(&sd->s_sibling); |
6f610764 | 364 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
365 | configfs_put(sd); |
366 | } | |
367 | } | |
7063fbf2 JB |
368 | } |
369 | return err; | |
370 | } | |
371 | ||
372 | static void remove_dir(struct dentry * d) | |
373 | { | |
374 | struct dentry * parent = dget(d->d_parent); | |
375 | struct configfs_dirent * sd; | |
376 | ||
377 | sd = d->d_fsdata; | |
6f610764 | 378 | spin_lock(&configfs_dirent_lock); |
e7515d06 | 379 | list_del_init(&sd->s_sibling); |
6f610764 | 380 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 | 381 | configfs_put(sd); |
2b0143b5 DH |
382 | if (d_really_is_positive(d)) |
383 | simple_rmdir(d_inode(parent),d); | |
7063fbf2 | 384 | |
a455589f | 385 | pr_debug(" o %pd removing done (%d)\n", d, d_count(d)); |
7063fbf2 JB |
386 | |
387 | dput(parent); | |
388 | } | |
389 | ||
390 | /** | |
391 | * configfs_remove_dir - remove an config_item's directory. | |
392 | * @item: config_item we're removing. | |
393 | * | |
394 | * The only thing special about this is that we remove any files in | |
395 | * the directory before we remove the directory, and we've inlined | |
396 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
397 | * |
398 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
399 | */ |
400 | ||
401 | static void configfs_remove_dir(struct config_item * item) | |
402 | { | |
403 | struct dentry * dentry = dget(item->ci_dentry); | |
404 | ||
405 | if (!dentry) | |
406 | return; | |
407 | ||
408 | remove_dir(dentry); | |
409 | /** | |
410 | * Drop reference from dget() on entrance. | |
411 | */ | |
412 | dput(dentry); | |
413 | } | |
414 | ||
415 | ||
416 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
417 | * attribute file | |
418 | */ | |
419 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
420 | { | |
421 | struct configfs_attribute * attr = sd->s_element; | |
422 | int error; | |
423 | ||
76ae281f | 424 | spin_lock(&configfs_dirent_lock); |
3d0f89bb JB |
425 | dentry->d_fsdata = configfs_get(sd); |
426 | sd->s_dentry = dentry; | |
76ae281f JB |
427 | spin_unlock(&configfs_dirent_lock); |
428 | ||
ce8d2cdf | 429 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
03607ace PA |
430 | (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ? |
431 | configfs_init_bin_file : | |
432 | configfs_init_file); | |
5cf3b560 | 433 | if (error) |
3d0f89bb | 434 | configfs_put(sd); |
5cf3b560 | 435 | return error; |
7063fbf2 JB |
436 | } |
437 | ||
438 | static struct dentry * configfs_lookup(struct inode *dir, | |
439 | struct dentry *dentry, | |
00cd8dd3 | 440 | unsigned int flags) |
7063fbf2 JB |
441 | { |
442 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
443 | struct configfs_dirent * sd; | |
444 | int found = 0; | |
2a109f2a LR |
445 | int err; |
446 | ||
447 | /* | |
448 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
449 | * being attached | |
450 | * | |
451 | * This forbids userspace to read/write attributes of items which may | |
452 | * not complete their initialization, since the dentries of the | |
453 | * attributes won't be instantiated. | |
454 | */ | |
455 | err = -ENOENT; | |
456 | if (!configfs_dirent_is_ready(parent_sd)) | |
457 | goto out; | |
7063fbf2 JB |
458 | |
459 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
460 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
461 | const unsigned char * name = configfs_get_name(sd); | |
462 | ||
463 | if (strcmp(name, dentry->d_name.name)) | |
464 | continue; | |
465 | ||
466 | found = 1; | |
467 | err = configfs_attach_attr(sd, dentry); | |
468 | break; | |
469 | } | |
470 | } | |
471 | ||
472 | if (!found) { | |
473 | /* | |
474 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
475 | * it must be negative. | |
476 | */ | |
fbc8d4c0 NP |
477 | if (dentry->d_name.len > NAME_MAX) |
478 | return ERR_PTR(-ENAMETOOLONG); | |
fbc8d4c0 NP |
479 | d_add(dentry, NULL); |
480 | return NULL; | |
7063fbf2 JB |
481 | } |
482 | ||
2a109f2a | 483 | out: |
7063fbf2 JB |
484 | return ERR_PTR(err); |
485 | } | |
486 | ||
487 | /* | |
488 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
489 | * attributes and are removed by rmdir(). We recurse, setting |
490 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
491 | * default detach. | |
492 | * If there is an error, the caller will reset the flags via | |
493 | * configfs_detach_rollback(). | |
7063fbf2 | 494 | */ |
48f35b7b | 495 | static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait) |
7063fbf2 JB |
496 | { |
497 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
498 | struct configfs_dirent *sd; | |
499 | int ret; | |
500 | ||
4768e9b1 LR |
501 | /* Mark that we're trying to drop the group */ |
502 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
503 | ||
7063fbf2 JB |
504 | ret = -EBUSY; |
505 | if (!list_empty(&parent_sd->s_links)) | |
506 | goto out; | |
507 | ||
508 | ret = 0; | |
509 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
510 | if (!sd->s_element || |
511 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
512 | continue; |
513 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
514 | /* Abort if racing with mkdir() */ |
515 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
48f35b7b AV |
516 | if (wait) |
517 | *wait= dget(sd->s_dentry); | |
6d8344ba LR |
518 | return -EAGAIN; |
519 | } | |
7063fbf2 | 520 | |
631d1feb JB |
521 | /* |
522 | * Yup, recursive. If there's a problem, blame | |
523 | * deep nesting of default_groups | |
524 | */ | |
48f35b7b | 525 | ret = configfs_detach_prep(sd->s_dentry, wait); |
7063fbf2 | 526 | if (!ret) |
e7515d06 | 527 | continue; |
7063fbf2 JB |
528 | } else |
529 | ret = -ENOTEMPTY; | |
530 | ||
531 | break; | |
532 | } | |
533 | ||
534 | out: | |
535 | return ret; | |
536 | } | |
537 | ||
538 | /* | |
b3e76af8 | 539 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
540 | * set. |
541 | */ | |
542 | static void configfs_detach_rollback(struct dentry *dentry) | |
543 | { | |
544 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
545 | struct configfs_dirent *sd; | |
546 | ||
4768e9b1 LR |
547 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
548 | ||
549 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
550 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 551 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
552 | } |
553 | ||
554 | static void detach_attrs(struct config_item * item) | |
555 | { | |
556 | struct dentry * dentry = dget(item->ci_dentry); | |
557 | struct configfs_dirent * parent_sd; | |
558 | struct configfs_dirent * sd, * tmp; | |
559 | ||
560 | if (!dentry) | |
561 | return; | |
562 | ||
563 | pr_debug("configfs %s: dropping attrs for dir\n", | |
564 | dentry->d_name.name); | |
565 | ||
566 | parent_sd = dentry->d_fsdata; | |
567 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
568 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
569 | continue; | |
6f610764 | 570 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 571 | list_del_init(&sd->s_sibling); |
6f610764 | 572 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
573 | configfs_drop_dentry(sd, dentry); |
574 | configfs_put(sd); | |
575 | } | |
576 | ||
577 | /** | |
578 | * Drop reference from dget() on entrance. | |
579 | */ | |
580 | dput(dentry); | |
581 | } | |
582 | ||
583 | static int populate_attrs(struct config_item *item) | |
584 | { | |
aa293583 | 585 | const struct config_item_type *t = item->ci_type; |
7063fbf2 | 586 | struct configfs_attribute *attr; |
03607ace | 587 | struct configfs_bin_attribute *bin_attr; |
7063fbf2 JB |
588 | int error = 0; |
589 | int i; | |
590 | ||
591 | if (!t) | |
592 | return -EINVAL; | |
593 | if (t->ct_attrs) { | |
594 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
595 | if ((error = configfs_create_file(item, attr))) | |
596 | break; | |
597 | } | |
598 | } | |
03607ace PA |
599 | if (t->ct_bin_attrs) { |
600 | for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) { | |
601 | error = configfs_create_bin_file(item, bin_attr); | |
602 | if (error) | |
603 | break; | |
604 | } | |
605 | } | |
7063fbf2 JB |
606 | |
607 | if (error) | |
608 | detach_attrs(item); | |
609 | ||
610 | return error; | |
611 | } | |
612 | ||
613 | static int configfs_attach_group(struct config_item *parent_item, | |
614 | struct config_item *item, | |
615 | struct dentry *dentry); | |
616 | static void configfs_detach_group(struct config_item *item); | |
617 | ||
618 | static void detach_groups(struct config_group *group) | |
619 | { | |
620 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
621 | struct dentry *child; | |
622 | struct configfs_dirent *parent_sd; | |
623 | struct configfs_dirent *sd, *tmp; | |
624 | ||
625 | if (!dentry) | |
626 | return; | |
627 | ||
628 | parent_sd = dentry->d_fsdata; | |
629 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
630 | if (!sd->s_element || | |
631 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
632 | continue; | |
633 | ||
634 | child = sd->s_dentry; | |
635 | ||
5955102c | 636 | inode_lock(d_inode(child)); |
b3e76af8 | 637 | |
7063fbf2 | 638 | configfs_detach_group(sd->s_element); |
2b0143b5 | 639 | d_inode(child)->i_flags |= S_DEAD; |
d83c49f3 | 640 | dont_mount(child); |
7063fbf2 | 641 | |
5955102c | 642 | inode_unlock(d_inode(child)); |
7063fbf2 JB |
643 | |
644 | d_delete(child); | |
645 | dput(child); | |
646 | } | |
647 | ||
648 | /** | |
649 | * Drop reference from dget() on entrance. | |
650 | */ | |
651 | dput(dentry); | |
652 | } | |
653 | ||
654 | /* | |
655 | * This fakes mkdir(2) on a default_groups[] entry. It | |
656 | * creates a dentry, attachs it, and then does fixup | |
657 | * on the sd->s_type. | |
658 | * | |
659 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
660 | * try using vfs_mkdir. Just a thought. | |
661 | */ | |
662 | static int create_default_group(struct config_group *parent_group, | |
663 | struct config_group *group) | |
664 | { | |
665 | int ret; | |
7063fbf2 JB |
666 | struct configfs_dirent *sd; |
667 | /* We trust the caller holds a reference to parent */ | |
668 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
669 | ||
670 | if (!group->cg_item.ci_name) | |
671 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
7063fbf2 JB |
672 | |
673 | ret = -ENOMEM; | |
ec193cf5 | 674 | child = d_alloc_name(parent, group->cg_item.ci_name); |
7063fbf2 JB |
675 | if (child) { |
676 | d_add(child, NULL); | |
677 | ||
678 | ret = configfs_attach_group(&parent_group->cg_item, | |
679 | &group->cg_item, child); | |
680 | if (!ret) { | |
681 | sd = child->d_fsdata; | |
682 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
683 | } else { | |
2b0143b5 | 684 | BUG_ON(d_inode(child)); |
df7f9967 | 685 | d_drop(child); |
7063fbf2 JB |
686 | dput(child); |
687 | } | |
688 | } | |
689 | ||
690 | return ret; | |
691 | } | |
692 | ||
693 | static int populate_groups(struct config_group *group) | |
694 | { | |
695 | struct config_group *new_group; | |
7063fbf2 | 696 | int ret = 0; |
7063fbf2 | 697 | |
1ae1602d CH |
698 | list_for_each_entry(new_group, &group->default_groups, group_entry) { |
699 | ret = create_default_group(group, new_group); | |
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, | |
813 | struct dentry *dentry) | |
814 | { | |
815 | int ret; | |
816 | ||
817 | ret = configfs_create_dir(item, dentry); | |
818 | if (!ret) { | |
819 | ret = populate_attrs(item); | |
820 | if (ret) { | |
2e2ce171 LR |
821 | /* |
822 | * We are going to remove an inode and its dentry but | |
823 | * the VFS may already have hit and used them. Thus, | |
824 | * we must lock them as rmdir() would. | |
825 | */ | |
5955102c | 826 | inode_lock(d_inode(dentry)); |
7063fbf2 | 827 | configfs_remove_dir(item); |
2b0143b5 | 828 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 829 | dont_mount(dentry); |
5955102c | 830 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
831 | d_delete(dentry); |
832 | } | |
833 | } | |
834 | ||
835 | return ret; | |
836 | } | |
837 | ||
2e2ce171 | 838 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
839 | static void configfs_detach_item(struct config_item *item) |
840 | { | |
841 | detach_attrs(item); | |
842 | configfs_remove_dir(item); | |
843 | } | |
844 | ||
845 | static int configfs_attach_group(struct config_item *parent_item, | |
846 | struct config_item *item, | |
847 | struct dentry *dentry) | |
848 | { | |
849 | int ret; | |
850 | struct configfs_dirent *sd; | |
851 | ||
852 | ret = configfs_attach_item(parent_item, item, dentry); | |
853 | if (!ret) { | |
854 | sd = dentry->d_fsdata; | |
855 | sd->s_type |= CONFIGFS_USET_DIR; | |
856 | ||
2e2ce171 LR |
857 | /* |
858 | * FYI, we're faking mkdir in populate_groups() | |
859 | * We must lock the group's inode to avoid races with the VFS | |
860 | * which can already hit the inode and try to add/remove entries | |
861 | * under it. | |
862 | * | |
863 | * We must also lock the inode to remove it safely in case of | |
864 | * error, as rmdir() would. | |
865 | */ | |
5955102c | 866 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
e74cc06d | 867 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
7063fbf2 JB |
868 | ret = populate_groups(to_config_group(item)); |
869 | if (ret) { | |
870 | configfs_detach_item(item); | |
2b0143b5 | 871 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 872 | dont_mount(dentry); |
7063fbf2 | 873 | } |
e74cc06d | 874 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
5955102c | 875 | inode_unlock(d_inode(dentry)); |
2e2ce171 LR |
876 | if (ret) |
877 | d_delete(dentry); | |
7063fbf2 JB |
878 | } |
879 | ||
880 | return ret; | |
881 | } | |
882 | ||
2e2ce171 | 883 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
884 | static void configfs_detach_group(struct config_item *item) |
885 | { | |
886 | detach_groups(to_config_group(item)); | |
887 | configfs_detach_item(item); | |
888 | } | |
889 | ||
299894cc JB |
890 | /* |
891 | * After the item has been detached from the filesystem view, we are | |
892 | * ready to tear it out of the hierarchy. Notify the client before | |
893 | * we do that so they can perform any cleanup that requires | |
894 | * navigating the hierarchy. A client does not need to provide this | |
895 | * callback. The subsystem semaphore MUST be held by the caller, and | |
896 | * references must be valid for both items. It also assumes the | |
897 | * caller has validated ci_type. | |
898 | */ | |
899 | static void client_disconnect_notify(struct config_item *parent_item, | |
900 | struct config_item *item) | |
901 | { | |
aa293583 | 902 | const struct config_item_type *type; |
299894cc JB |
903 | |
904 | type = parent_item->ci_type; | |
905 | BUG_ON(!type); | |
906 | ||
907 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
908 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
909 | item); | |
910 | } | |
911 | ||
7063fbf2 JB |
912 | /* |
913 | * Drop the initial reference from make_item()/make_group() | |
914 | * This function assumes that reference is held on item | |
915 | * and that item holds a valid reference to the parent. Also, it | |
916 | * assumes the caller has validated ci_type. | |
917 | */ | |
918 | static void client_drop_item(struct config_item *parent_item, | |
919 | struct config_item *item) | |
920 | { | |
aa293583 | 921 | const struct config_item_type *type; |
7063fbf2 JB |
922 | |
923 | type = parent_item->ci_type; | |
924 | BUG_ON(!type); | |
925 | ||
eed7a0db JB |
926 | /* |
927 | * If ->drop_item() exists, it is responsible for the | |
928 | * config_item_put(). | |
929 | */ | |
7063fbf2 JB |
930 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
931 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 932 | item); |
7063fbf2 JB |
933 | else |
934 | config_item_put(item); | |
935 | } | |
936 | ||
631d1feb JB |
937 | #ifdef DEBUG |
938 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
939 | { | |
c6686931 | 940 | pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
631d1feb | 941 | |
c6686931 | 942 | #define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type); |
631d1feb JB |
943 | type_print(CONFIGFS_ROOT); |
944 | type_print(CONFIGFS_DIR); | |
945 | type_print(CONFIGFS_ITEM_ATTR); | |
946 | type_print(CONFIGFS_ITEM_LINK); | |
947 | type_print(CONFIGFS_USET_DIR); | |
948 | type_print(CONFIGFS_USET_DEFAULT); | |
949 | type_print(CONFIGFS_USET_DROPPING); | |
950 | #undef type_print | |
951 | } | |
952 | ||
953 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
954 | { | |
955 | struct configfs_dirent *child_sd; | |
956 | int ret = 0; | |
957 | ||
958 | configfs_dump_one(sd, level); | |
959 | ||
960 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
961 | return 0; | |
962 | ||
963 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
964 | ret = configfs_dump(child_sd, level + 2); | |
965 | if (ret) | |
966 | break; | |
967 | } | |
968 | ||
969 | return ret; | |
970 | } | |
971 | #endif | |
972 | ||
973 | ||
974 | /* | |
975 | * configfs_depend_item() and configfs_undepend_item() | |
976 | * | |
977 | * WARNING: Do not call these from a configfs callback! | |
978 | * | |
979 | * This describes these functions and their helpers. | |
980 | * | |
981 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 982 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
983 | * it. The idea is to give client modules as simple an interface as |
984 | * possible. When a system asks them to depend on an item, they just | |
985 | * call configfs_depend_item(). If the item is live and the client | |
986 | * driver is in good shape, we'll happily do the work for them. | |
987 | * | |
988 | * Why is the locking complex? Because configfs uses the VFS to handle | |
989 | * all locking, but this function is called outside the normal | |
990 | * VFS->configfs path. So it must take VFS locks to prevent the | |
991 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
992 | * why you can't call these functions underneath configfs callbacks. | |
993 | * | |
994 | * Note, btw, that this can be called at *any* time, even when a configfs | |
995 | * subsystem isn't registered, or when configfs is loading or unloading. | |
996 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
997 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
998 | * If we can find the target item in the | |
631d1feb | 999 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
1000 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1001 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
1002 | */ |
1003 | ||
1004 | /* | |
1005 | * configfs_depend_prep() | |
1006 | * | |
1007 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1008 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1009 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1010 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1011 | * do that so we can unlock it if we find nothing. | |
1012 | * | |
1013 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1014 | * our object. |
1015 | * We deliberately ignore items tagged as dropping since they are virtually | |
1016 | * dead, as well as items in the middle of attachment since they virtually | |
1017 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1018 | * rmdir(). | |
1019 | * Note: subdirectories in the middle of attachment start with s_type = | |
1020 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1021 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1022 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1023 | * |
420118ca | 1024 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1025 | * |
1026 | * This adds a requirement that all config_items be unique! | |
1027 | * | |
420118ca | 1028 | * This is recursive. There isn't |
631d1feb JB |
1029 | * much on the stack, though, so folks that need this function - be careful |
1030 | * about your stack! Patches will be accepted to make it iterative. | |
1031 | */ | |
1032 | static int configfs_depend_prep(struct dentry *origin, | |
1033 | struct config_item *target) | |
1034 | { | |
49deb4bc | 1035 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1036 | int ret = 0; |
1037 | ||
49deb4bc WY |
1038 | BUG_ON(!origin || !origin->d_fsdata); |
1039 | sd = origin->d_fsdata; | |
631d1feb | 1040 | |
631d1feb JB |
1041 | if (sd->s_element == target) /* Boo-yah */ |
1042 | goto out; | |
1043 | ||
1044 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1045 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1046 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1047 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1048 | ret = configfs_depend_prep(child_sd->s_dentry, |
1049 | target); | |
1050 | if (!ret) | |
1051 | goto out; /* Child path boo-yah */ | |
1052 | } | |
1053 | } | |
1054 | ||
1055 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1056 | ret = -ENOENT; |
1057 | ||
1058 | out: | |
1059 | return ret; | |
1060 | } | |
1061 | ||
9fb434e7 KO |
1062 | static int configfs_do_depend_item(struct dentry *subsys_dentry, |
1063 | struct config_item *target) | |
1064 | { | |
1065 | struct configfs_dirent *p; | |
1066 | int ret; | |
1067 | ||
1068 | spin_lock(&configfs_dirent_lock); | |
1069 | /* Scan the tree, return 0 if found */ | |
1070 | ret = configfs_depend_prep(subsys_dentry, target); | |
1071 | if (ret) | |
1072 | goto out_unlock_dirent_lock; | |
1073 | ||
1074 | /* | |
1075 | * We are sure that the item is not about to be removed by rmdir(), and | |
1076 | * not in the middle of attachment by mkdir(). | |
1077 | */ | |
1078 | p = target->ci_dentry->d_fsdata; | |
1079 | p->s_dependent_count += 1; | |
1080 | ||
1081 | out_unlock_dirent_lock: | |
1082 | spin_unlock(&configfs_dirent_lock); | |
1083 | ||
1084 | return ret; | |
1085 | } | |
1086 | ||
9a70adff KO |
1087 | static inline struct configfs_dirent * |
1088 | configfs_find_subsys_dentry(struct configfs_dirent *root_sd, | |
1089 | struct config_item *subsys_item) | |
1090 | { | |
1091 | struct configfs_dirent *p; | |
1092 | struct configfs_dirent *ret = NULL; | |
1093 | ||
1094 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1095 | if (p->s_type & CONFIGFS_DIR && | |
1096 | p->s_element == subsys_item) { | |
1097 | ret = p; | |
1098 | break; | |
1099 | } | |
1100 | } | |
1101 | ||
1102 | return ret; | |
1103 | } | |
1104 | ||
1105 | ||
631d1feb JB |
1106 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1107 | struct config_item *target) | |
1108 | { | |
1109 | int ret; | |
9a70adff | 1110 | struct configfs_dirent *subsys_sd; |
631d1feb | 1111 | struct config_item *s_item = &subsys->su_group.cg_item; |
b7c177fc | 1112 | struct dentry *root; |
631d1feb JB |
1113 | |
1114 | /* | |
1115 | * Pin the configfs filesystem. This means we can safely access | |
1116 | * the root of the configfs filesystem. | |
1117 | */ | |
2a152ad3 AV |
1118 | root = configfs_pin_fs(); |
1119 | if (IS_ERR(root)) | |
1120 | return PTR_ERR(root); | |
631d1feb JB |
1121 | |
1122 | /* | |
1123 | * Next, lock the root directory. We're going to check that the | |
1124 | * subsystem is really registered, and so we need to lock out | |
1125 | * configfs_[un]register_subsystem(). | |
1126 | */ | |
5955102c | 1127 | inode_lock(d_inode(root)); |
631d1feb | 1128 | |
9a70adff | 1129 | subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item); |
631d1feb JB |
1130 | if (!subsys_sd) { |
1131 | ret = -ENOENT; | |
1132 | goto out_unlock_fs; | |
1133 | } | |
1134 | ||
1135 | /* Ok, now we can trust subsys/s_item */ | |
9fb434e7 | 1136 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); |
631d1feb | 1137 | |
631d1feb | 1138 | out_unlock_fs: |
5955102c | 1139 | inode_unlock(d_inode(root)); |
631d1feb JB |
1140 | |
1141 | /* | |
1142 | * If we succeeded, the fs is pinned via other methods. If not, | |
1143 | * we're done with it anyway. So release_fs() is always right. | |
1144 | */ | |
1145 | configfs_release_fs(); | |
1146 | ||
1147 | return ret; | |
1148 | } | |
1149 | EXPORT_SYMBOL(configfs_depend_item); | |
1150 | ||
1151 | /* | |
1152 | * Release the dependent linkage. This is much simpler than | |
1153 | * configfs_depend_item() because we know that that the client driver is | |
1154 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. | |
1155 | */ | |
9a9e3415 | 1156 | void configfs_undepend_item(struct config_item *target) |
631d1feb JB |
1157 | { |
1158 | struct configfs_dirent *sd; | |
1159 | ||
1160 | /* | |
420118ca LR |
1161 | * Since we can trust everything is pinned, we just need |
1162 | * configfs_dirent_lock. | |
631d1feb | 1163 | */ |
420118ca | 1164 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1165 | |
1166 | sd = target->ci_dentry->d_fsdata; | |
1167 | BUG_ON(sd->s_dependent_count < 1); | |
1168 | ||
1169 | sd->s_dependent_count -= 1; | |
1170 | ||
1171 | /* | |
1172 | * After this unlock, we cannot trust the item to stay alive! | |
1173 | * DO NOT REFERENCE item after this unlock. | |
1174 | */ | |
420118ca | 1175 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1176 | } |
1177 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1178 | |
d79d75b5 KO |
1179 | /* |
1180 | * caller_subsys is a caller's subsystem not target's. This is used to | |
1181 | * determine if we should lock root and check subsys or not. When we are | |
1182 | * in the same subsystem as our target there is no need to do locking as | |
1183 | * we know that subsys is valid and is not unregistered during this function | |
1184 | * as we are called from callback of one of his children and VFS holds a lock | |
1185 | * on some inode. Otherwise we have to lock our root to ensure that target's | |
1186 | * subsystem it is not unregistered during this function. | |
1187 | */ | |
1188 | int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, | |
1189 | struct config_item *target) | |
1190 | { | |
1191 | struct configfs_subsystem *target_subsys; | |
1192 | struct config_group *root, *parent; | |
1193 | struct configfs_dirent *subsys_sd; | |
1194 | int ret = -ENOENT; | |
1195 | ||
1196 | /* Disallow this function for configfs root */ | |
1197 | if (configfs_is_root(target)) | |
1198 | return -EINVAL; | |
1199 | ||
1200 | parent = target->ci_group; | |
1201 | /* | |
1202 | * This may happen when someone is trying to depend root | |
1203 | * directory of some subsystem | |
1204 | */ | |
1205 | if (configfs_is_root(&parent->cg_item)) { | |
1206 | target_subsys = to_configfs_subsystem(to_config_group(target)); | |
1207 | root = parent; | |
1208 | } else { | |
1209 | target_subsys = parent->cg_subsys; | |
1210 | /* Find a cofnigfs root as we may need it for locking */ | |
1211 | for (root = parent; !configfs_is_root(&root->cg_item); | |
1212 | root = root->cg_item.ci_group) | |
1213 | ; | |
1214 | } | |
1215 | ||
1216 | if (target_subsys != caller_subsys) { | |
1217 | /* | |
1218 | * We are in other configfs subsystem, so we have to do | |
1219 | * additional locking to prevent other subsystem from being | |
1220 | * unregistered | |
1221 | */ | |
5955102c | 1222 | inode_lock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1223 | |
1224 | /* | |
1225 | * As we are trying to depend item from other subsystem | |
1226 | * we have to check if this subsystem is still registered | |
1227 | */ | |
1228 | subsys_sd = configfs_find_subsys_dentry( | |
1229 | root->cg_item.ci_dentry->d_fsdata, | |
1230 | &target_subsys->su_group.cg_item); | |
1231 | if (!subsys_sd) | |
1232 | goto out_root_unlock; | |
1233 | } else { | |
1234 | subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata; | |
1235 | } | |
1236 | ||
1237 | /* Now we can execute core of depend item */ | |
1238 | ret = configfs_do_depend_item(subsys_sd->s_dentry, target); | |
1239 | ||
1240 | if (target_subsys != caller_subsys) | |
1241 | out_root_unlock: | |
1242 | /* | |
1243 | * We were called from subsystem other than our target so we | |
1244 | * took some locks so now it's time to release them | |
1245 | */ | |
5955102c | 1246 | inode_unlock(d_inode(root->cg_item.ci_dentry)); |
d79d75b5 KO |
1247 | |
1248 | return ret; | |
1249 | } | |
1250 | EXPORT_SYMBOL(configfs_depend_item_unlocked); | |
1251 | ||
18bb1db3 | 1252 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
7063fbf2 | 1253 | { |
a6795e9e JB |
1254 | int ret = 0; |
1255 | int module_got = 0; | |
1256 | struct config_group *group = NULL; | |
1257 | struct config_item *item = NULL; | |
7063fbf2 JB |
1258 | struct config_item *parent_item; |
1259 | struct configfs_subsystem *subsys; | |
1260 | struct configfs_dirent *sd; | |
aa293583 | 1261 | const struct config_item_type *type; |
70526b67 | 1262 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
7063fbf2 JB |
1263 | char *name; |
1264 | ||
7063fbf2 | 1265 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1266 | |
1267 | /* | |
1268 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1269 | * being attached | |
1270 | */ | |
1271 | if (!configfs_dirent_is_ready(sd)) { | |
1272 | ret = -ENOENT; | |
1273 | goto out; | |
1274 | } | |
1275 | ||
84efad1a JB |
1276 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1277 | ret = -EPERM; | |
1278 | goto out; | |
1279 | } | |
7063fbf2 | 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 JB |
1382 | if (group) |
1383 | ret = configfs_attach_group(parent_item, item, dentry); | |
1384 | else | |
1385 | ret = configfs_attach_item(parent_item, item, dentry); | |
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); | |
1422 | ||
1423 | out: | |
7063fbf2 JB |
1424 | return ret; |
1425 | } | |
1426 | ||
1427 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1428 | { | |
1429 | struct config_item *parent_item; | |
1430 | struct config_item *item; | |
1431 | struct configfs_subsystem *subsys; | |
1432 | struct configfs_dirent *sd; | |
70526b67 | 1433 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1434 | int ret; |
1435 | ||
7063fbf2 JB |
1436 | sd = dentry->d_fsdata; |
1437 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1438 | return -EPERM; | |
1439 | ||
84efad1a | 1440 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1441 | parent_item = configfs_get_config_item(dentry->d_parent); |
1442 | subsys = to_config_group(parent_item)->cg_subsys; | |
1443 | BUG_ON(!subsys); | |
1444 | ||
1445 | if (!parent_item->ci_type) { | |
1446 | config_item_put(parent_item); | |
1447 | return -EINVAL; | |
1448 | } | |
1449 | ||
70526b67 JB |
1450 | /* configfs_mkdir() shouldn't have allowed this */ |
1451 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1452 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1453 | ||
9a73d78c LR |
1454 | /* |
1455 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1456 | * the new link is temporarily attached | |
1457 | */ | |
6d8344ba | 1458 | do { |
48f35b7b | 1459 | struct dentry *wait; |
6d8344ba | 1460 | |
de6bf18e LR |
1461 | mutex_lock(&configfs_symlink_mutex); |
1462 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1463 | /* |
1464 | * Here's where we check for dependents. We're protected by | |
1465 | * configfs_dirent_lock. | |
1466 | * If no dependent, atomically tag the item as dropping. | |
1467 | */ | |
1468 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1469 | if (!ret) { | |
48f35b7b | 1470 | ret = configfs_detach_prep(dentry, &wait); |
420118ca LR |
1471 | if (ret) |
1472 | configfs_detach_rollback(dentry); | |
1473 | } | |
de6bf18e LR |
1474 | spin_unlock(&configfs_dirent_lock); |
1475 | mutex_unlock(&configfs_symlink_mutex); | |
1476 | ||
1477 | if (ret) { | |
6d8344ba LR |
1478 | if (ret != -EAGAIN) { |
1479 | config_item_put(parent_item); | |
1480 | return ret; | |
1481 | } | |
1482 | ||
1483 | /* Wait until the racing operation terminates */ | |
48f35b7b AV |
1484 | inode_lock(d_inode(wait)); |
1485 | inode_unlock(d_inode(wait)); | |
1486 | dput(wait); | |
6d8344ba LR |
1487 | } |
1488 | } while (ret == -EAGAIN); | |
7063fbf2 | 1489 | |
84efad1a | 1490 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1491 | item = configfs_get_config_item(dentry); |
1492 | ||
1493 | /* Drop reference from above, item already holds one. */ | |
1494 | config_item_put(parent_item); | |
1495 | ||
1496 | if (item->ci_type) | |
70526b67 | 1497 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1498 | |
1499 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1500 | configfs_detach_group(item); | |
1501 | ||
e6bd07ae | 1502 | mutex_lock(&subsys->su_mutex); |
299894cc | 1503 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1504 | unlink_group(to_config_group(item)); |
1505 | } else { | |
1506 | configfs_detach_item(item); | |
1507 | ||
e6bd07ae | 1508 | mutex_lock(&subsys->su_mutex); |
299894cc | 1509 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1510 | unlink_obj(item); |
1511 | } | |
1512 | ||
1513 | client_drop_item(parent_item, item); | |
e6bd07ae | 1514 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1515 | |
1516 | /* Drop our reference from above */ | |
1517 | config_item_put(item); | |
1518 | ||
70526b67 JB |
1519 | module_put(dead_item_owner); |
1520 | module_put(subsys_owner); | |
7063fbf2 JB |
1521 | |
1522 | return 0; | |
1523 | } | |
1524 | ||
754661f1 | 1525 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1526 | .mkdir = configfs_mkdir, |
1527 | .rmdir = configfs_rmdir, | |
1528 | .symlink = configfs_symlink, | |
1529 | .unlink = configfs_unlink, | |
1530 | .lookup = configfs_lookup, | |
3d0f89bb | 1531 | .setattr = configfs_setattr, |
7063fbf2 JB |
1532 | }; |
1533 | ||
81d44ed1 AV |
1534 | const struct inode_operations configfs_root_inode_operations = { |
1535 | .lookup = configfs_lookup, | |
1536 | .setattr = configfs_setattr, | |
1537 | }; | |
1538 | ||
7063fbf2 JB |
1539 | #if 0 |
1540 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
1541 | { | |
1542 | int error = 0; | |
1543 | struct dentry * new_dentry, * parent; | |
1544 | ||
1545 | if (!strcmp(config_item_name(item), new_name)) | |
1546 | return -EINVAL; | |
1547 | ||
1548 | if (!item->parent) | |
1549 | return -EINVAL; | |
1550 | ||
1551 | down_write(&configfs_rename_sem); | |
1552 | parent = item->parent->dentry; | |
1553 | ||
5955102c | 1554 | inode_lock(d_inode(parent)); |
7063fbf2 JB |
1555 | |
1556 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
1557 | if (!IS_ERR(new_dentry)) { | |
2b0143b5 | 1558 | if (d_really_is_negative(new_dentry)) { |
7063fbf2 JB |
1559 | error = config_item_set_name(item, "%s", new_name); |
1560 | if (!error) { | |
1561 | d_add(new_dentry, NULL); | |
1562 | d_move(item->dentry, new_dentry); | |
1563 | } | |
1564 | else | |
1565 | d_delete(new_dentry); | |
1566 | } else | |
1567 | error = -EEXIST; | |
1568 | dput(new_dentry); | |
1569 | } | |
5955102c | 1570 | inode_unlock(d_inode(parent)); |
7063fbf2 JB |
1571 | up_write(&configfs_rename_sem); |
1572 | ||
1573 | return error; | |
1574 | } | |
1575 | #endif | |
1576 | ||
1577 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
1578 | { | |
867fa491 | 1579 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1580 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1581 | int err; |
7063fbf2 | 1582 | |
5955102c | 1583 | inode_lock(d_inode(dentry)); |
2a109f2a LR |
1584 | /* |
1585 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1586 | * being attached | |
1587 | */ | |
1588 | err = -ENOENT; | |
1589 | if (configfs_dirent_is_ready(parent_sd)) { | |
420118ca | 1590 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0); |
2a109f2a LR |
1591 | if (IS_ERR(file->private_data)) |
1592 | err = PTR_ERR(file->private_data); | |
1593 | else | |
1594 | err = 0; | |
1595 | } | |
5955102c | 1596 | inode_unlock(d_inode(dentry)); |
7063fbf2 | 1597 | |
2a109f2a | 1598 | return err; |
7063fbf2 JB |
1599 | } |
1600 | ||
1601 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1602 | { | |
867fa491 | 1603 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1604 | struct configfs_dirent * cursor = file->private_data; |
1605 | ||
5955102c | 1606 | inode_lock(d_inode(dentry)); |
6f610764 | 1607 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1608 | list_del_init(&cursor->s_sibling); |
6f610764 | 1609 | spin_unlock(&configfs_dirent_lock); |
5955102c | 1610 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
1611 | |
1612 | release_configfs_dirent(cursor); | |
1613 | ||
1614 | return 0; | |
1615 | } | |
1616 | ||
1617 | /* Relationship between s_mode and the DT_xxx types */ | |
1618 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1619 | { | |
1620 | return (sd->s_mode >> 12) & 15; | |
1621 | } | |
1622 | ||
52018855 | 1623 | static int configfs_readdir(struct file *file, struct dir_context *ctx) |
7063fbf2 | 1624 | { |
52018855 | 1625 | struct dentry *dentry = file->f_path.dentry; |
b7c177fc | 1626 | struct super_block *sb = dentry->d_sb; |
7063fbf2 | 1627 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
52018855 | 1628 | struct configfs_dirent *cursor = file->private_data; |
7063fbf2 | 1629 | struct list_head *p, *q = &cursor->s_sibling; |
24307aa1 | 1630 | ino_t ino = 0; |
7063fbf2 | 1631 | |
52018855 AV |
1632 | if (!dir_emit_dots(file, ctx)) |
1633 | return 0; | |
a01b3007 AV |
1634 | spin_lock(&configfs_dirent_lock); |
1635 | if (ctx->pos == 2) | |
52018855 | 1636 | list_move(q, &parent_sd->s_children); |
52018855 AV |
1637 | for (p = q->next; p != &parent_sd->s_children; p = p->next) { |
1638 | struct configfs_dirent *next; | |
1639 | const char *name; | |
1640 | int len; | |
1641 | struct inode *inode = NULL; | |
1642 | ||
1643 | next = list_entry(p, struct configfs_dirent, s_sibling); | |
1644 | if (!next->s_element) | |
1645 | continue; | |
7063fbf2 | 1646 | |
52018855 AV |
1647 | /* |
1648 | * We'll have a dentry and an inode for | |
1649 | * PINNED items and for open attribute | |
1650 | * files. We lock here to prevent a race | |
1651 | * with configfs_d_iput() clearing | |
1652 | * s_dentry before calling iput(). | |
1653 | * | |
1654 | * Why do we go to the trouble? If | |
1655 | * someone has an attribute file open, | |
1656 | * the inode number should match until | |
1657 | * they close it. Beyond that, we don't | |
1658 | * care. | |
1659 | */ | |
52018855 AV |
1660 | dentry = next->s_dentry; |
1661 | if (dentry) | |
2b0143b5 | 1662 | inode = d_inode(dentry); |
52018855 AV |
1663 | if (inode) |
1664 | ino = inode->i_ino; | |
1665 | spin_unlock(&configfs_dirent_lock); | |
1666 | if (!inode) | |
1667 | ino = iunique(sb, 2); | |
7063fbf2 | 1668 | |
a01b3007 AV |
1669 | name = configfs_get_name(next); |
1670 | len = strlen(name); | |
1671 | ||
52018855 AV |
1672 | if (!dir_emit(ctx, name, len, ino, dt_type(next))) |
1673 | return 0; | |
7063fbf2 | 1674 | |
52018855 AV |
1675 | spin_lock(&configfs_dirent_lock); |
1676 | list_move(q, p); | |
52018855 AV |
1677 | p = q; |
1678 | ctx->pos++; | |
7063fbf2 | 1679 | } |
a01b3007 | 1680 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1681 | return 0; |
1682 | } | |
1683 | ||
965c8e59 | 1684 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1685 | { |
867fa491 | 1686 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1687 | |
965c8e59 | 1688 | switch (whence) { |
7063fbf2 JB |
1689 | case 1: |
1690 | offset += file->f_pos; | |
1691 | case 0: | |
1692 | if (offset >= 0) | |
1693 | break; | |
1694 | default: | |
7063fbf2 JB |
1695 | return -EINVAL; |
1696 | } | |
1697 | if (offset != file->f_pos) { | |
1698 | file->f_pos = offset; | |
1699 | if (file->f_pos >= 2) { | |
1700 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1701 | struct configfs_dirent *cursor = file->private_data; | |
1702 | struct list_head *p; | |
1703 | loff_t n = file->f_pos - 2; | |
1704 | ||
6f610764 | 1705 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1706 | list_del(&cursor->s_sibling); |
1707 | p = sd->s_children.next; | |
1708 | while (n && p != &sd->s_children) { | |
1709 | struct configfs_dirent *next; | |
1710 | next = list_entry(p, struct configfs_dirent, | |
1711 | s_sibling); | |
1712 | if (next->s_element) | |
1713 | n--; | |
1714 | p = p->next; | |
1715 | } | |
1716 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1717 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1718 | } |
1719 | } | |
7063fbf2 JB |
1720 | return offset; |
1721 | } | |
1722 | ||
4b6f5d20 | 1723 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1724 | .open = configfs_dir_open, |
1725 | .release = configfs_dir_close, | |
1726 | .llseek = configfs_dir_lseek, | |
1727 | .read = generic_read_dir, | |
a01b3007 | 1728 | .iterate_shared = configfs_readdir, |
7063fbf2 JB |
1729 | }; |
1730 | ||
5cf6a51e DB |
1731 | /** |
1732 | * configfs_register_group - creates a parent-child relation between two groups | |
1733 | * @parent_group: parent group | |
1734 | * @group: child group | |
1735 | * | |
1736 | * link groups, creates dentry for the child and attaches it to the | |
1737 | * parent dentry. | |
1738 | * | |
1739 | * Return: 0 on success, negative errno code on error | |
1740 | */ | |
1741 | int configfs_register_group(struct config_group *parent_group, | |
1742 | struct config_group *group) | |
1743 | { | |
1744 | struct configfs_subsystem *subsys = parent_group->cg_subsys; | |
1745 | struct dentry *parent; | |
1746 | int ret; | |
1747 | ||
1748 | mutex_lock(&subsys->su_mutex); | |
1749 | link_group(parent_group, group); | |
1750 | mutex_unlock(&subsys->su_mutex); | |
1751 | ||
1752 | parent = parent_group->cg_item.ci_dentry; | |
1753 | ||
5955102c | 1754 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
5cf6a51e | 1755 | ret = create_default_group(parent_group, group); |
4dc146d4 Y |
1756 | if (ret) |
1757 | goto err_out; | |
1758 | ||
1759 | spin_lock(&configfs_dirent_lock); | |
1760 | configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); | |
1761 | spin_unlock(&configfs_dirent_lock); | |
1762 | inode_unlock(d_inode(parent)); | |
1763 | return 0; | |
1764 | err_out: | |
5955102c | 1765 | inode_unlock(d_inode(parent)); |
4dc146d4 Y |
1766 | mutex_lock(&subsys->su_mutex); |
1767 | unlink_group(group); | |
1768 | mutex_unlock(&subsys->su_mutex); | |
5cf6a51e DB |
1769 | return ret; |
1770 | } | |
1771 | EXPORT_SYMBOL(configfs_register_group); | |
1772 | ||
1773 | /** | |
1774 | * configfs_unregister_group() - unregisters a child group from its parent | |
1775 | * @group: parent group to be unregistered | |
1776 | * | |
1777 | * Undoes configfs_register_group() | |
1778 | */ | |
1779 | void configfs_unregister_group(struct config_group *group) | |
1780 | { | |
1781 | struct configfs_subsystem *subsys = group->cg_subsys; | |
1782 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1783 | struct dentry *parent = group->cg_item.ci_parent->ci_dentry; | |
1784 | ||
cc57c073 MC |
1785 | mutex_lock(&subsys->su_mutex); |
1786 | if (!group->cg_item.ci_parent->ci_group) { | |
1787 | /* | |
1788 | * The parent has already been unlinked and detached | |
1789 | * due to a rmdir. | |
1790 | */ | |
1791 | goto unlink_group; | |
1792 | } | |
1793 | mutex_unlock(&subsys->su_mutex); | |
1794 | ||
5955102c | 1795 | inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); |
5cf6a51e DB |
1796 | spin_lock(&configfs_dirent_lock); |
1797 | configfs_detach_prep(dentry, NULL); | |
1798 | spin_unlock(&configfs_dirent_lock); | |
1799 | ||
1800 | configfs_detach_group(&group->cg_item); | |
1801 | d_inode(dentry)->i_flags |= S_DEAD; | |
1802 | dont_mount(dentry); | |
1803 | d_delete(dentry); | |
5955102c | 1804 | inode_unlock(d_inode(parent)); |
5cf6a51e DB |
1805 | |
1806 | dput(dentry); | |
1807 | ||
1808 | mutex_lock(&subsys->su_mutex); | |
cc57c073 | 1809 | unlink_group: |
5cf6a51e DB |
1810 | unlink_group(group); |
1811 | mutex_unlock(&subsys->su_mutex); | |
1812 | } | |
1813 | EXPORT_SYMBOL(configfs_unregister_group); | |
1814 | ||
1815 | /** | |
1816 | * configfs_register_default_group() - allocates and registers a child group | |
1817 | * @parent_group: parent group | |
1818 | * @name: child group name | |
1819 | * @item_type: child item type description | |
1820 | * | |
1821 | * boilerplate to allocate and register a child group with its parent. We need | |
1822 | * kzalloc'ed memory because child's default_group is initially empty. | |
1823 | * | |
1824 | * Return: allocated config group or ERR_PTR() on error | |
1825 | */ | |
1826 | struct config_group * | |
1827 | configfs_register_default_group(struct config_group *parent_group, | |
1828 | const char *name, | |
aa293583 | 1829 | const struct config_item_type *item_type) |
5cf6a51e DB |
1830 | { |
1831 | int ret; | |
1832 | struct config_group *group; | |
1833 | ||
1834 | group = kzalloc(sizeof(*group), GFP_KERNEL); | |
1835 | if (!group) | |
1836 | return ERR_PTR(-ENOMEM); | |
1837 | config_group_init_type_name(group, name, item_type); | |
1838 | ||
1839 | ret = configfs_register_group(parent_group, group); | |
1840 | if (ret) { | |
1841 | kfree(group); | |
1842 | return ERR_PTR(ret); | |
1843 | } | |
1844 | return group; | |
1845 | } | |
1846 | EXPORT_SYMBOL(configfs_register_default_group); | |
1847 | ||
1848 | /** | |
1849 | * configfs_unregister_default_group() - unregisters and frees a child group | |
1850 | * @group: the group to act on | |
1851 | */ | |
1852 | void configfs_unregister_default_group(struct config_group *group) | |
1853 | { | |
1854 | configfs_unregister_group(group); | |
1855 | kfree(group); | |
1856 | } | |
1857 | EXPORT_SYMBOL(configfs_unregister_default_group); | |
1858 | ||
7063fbf2 JB |
1859 | int configfs_register_subsystem(struct configfs_subsystem *subsys) |
1860 | { | |
1861 | int err; | |
1862 | struct config_group *group = &subsys->su_group; | |
7063fbf2 | 1863 | struct dentry *dentry; |
b7c177fc | 1864 | struct dentry *root; |
7063fbf2 JB |
1865 | struct configfs_dirent *sd; |
1866 | ||
2a152ad3 AV |
1867 | root = configfs_pin_fs(); |
1868 | if (IS_ERR(root)) | |
1869 | return PTR_ERR(root); | |
7063fbf2 JB |
1870 | |
1871 | if (!group->cg_item.ci_name) | |
1872 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1873 | ||
b7c177fc | 1874 | sd = root->d_fsdata; |
7063fbf2 JB |
1875 | link_group(to_config_group(sd->s_element), group); |
1876 | ||
5955102c | 1877 | inode_lock_nested(d_inode(root), I_MUTEX_PARENT); |
7063fbf2 | 1878 | |
7063fbf2 | 1879 | err = -ENOMEM; |
ec193cf5 | 1880 | dentry = d_alloc_name(root, group->cg_item.ci_name); |
afdf04ea JB |
1881 | if (dentry) { |
1882 | d_add(dentry, NULL); | |
7063fbf2 | 1883 | |
afdf04ea JB |
1884 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1885 | dentry); | |
1886 | if (err) { | |
2b0143b5 | 1887 | BUG_ON(d_inode(dentry)); |
df7f9967 | 1888 | d_drop(dentry); |
afdf04ea | 1889 | dput(dentry); |
2a109f2a LR |
1890 | } else { |
1891 | spin_lock(&configfs_dirent_lock); | |
1892 | configfs_dir_set_ready(dentry->d_fsdata); | |
1893 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1894 | } |
1895 | } | |
7063fbf2 | 1896 | |
5955102c | 1897 | inode_unlock(d_inode(root)); |
7063fbf2 | 1898 | |
afdf04ea JB |
1899 | if (err) { |
1900 | unlink_group(group); | |
1901 | configfs_release_fs(); | |
7063fbf2 JB |
1902 | } |
1903 | ||
1904 | return err; | |
1905 | } | |
1906 | ||
1907 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1908 | { | |
1909 | struct config_group *group = &subsys->su_group; | |
1910 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1911 | struct dentry *root = dentry->d_sb->s_root; |
7063fbf2 | 1912 | |
b7c177fc | 1913 | if (dentry->d_parent != root) { |
1d88aa44 | 1914 | pr_err("Tried to unregister non-subsystem!\n"); |
7063fbf2 JB |
1915 | return; |
1916 | } | |
1917 | ||
5955102c | 1918 | inode_lock_nested(d_inode(root), |
55ed1602 | 1919 | I_MUTEX_PARENT); |
5955102c | 1920 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
9a73d78c | 1921 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1922 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1923 | if (configfs_detach_prep(dentry, NULL)) { |
1d88aa44 | 1924 | pr_err("Tried to unregister non-empty subsystem!\n"); |
7063fbf2 | 1925 | } |
b3e76af8 | 1926 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1927 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 | 1928 | configfs_detach_group(&group->cg_item); |
2b0143b5 | 1929 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 1930 | dont_mount(dentry); |
5955102c | 1931 | inode_unlock(d_inode(dentry)); |
7063fbf2 JB |
1932 | |
1933 | d_delete(dentry); | |
1934 | ||
5955102c | 1935 | inode_unlock(d_inode(root)); |
7063fbf2 JB |
1936 | |
1937 | dput(dentry); | |
1938 | ||
1939 | unlink_group(group); | |
1940 | configfs_release_fs(); | |
1941 | } | |
1942 | ||
1943 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1944 | EXPORT_SYMBOL(configfs_unregister_subsystem); |