Line data Source code
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>
33 : #include <linux/err.h>
34 :
35 : #include <linux/configfs.h>
36 : #include "configfs_internal.h"
37 :
38 1 : DECLARE_RWSEM(configfs_rename_sem);
39 : /*
40 : * Protects mutations of configfs_dirent linkage together with proper i_mutex
41 : * Also protects mutations of symlinks linkage to target configfs_dirent
42 : * Mutators of configfs_dirent linkage must *both* have the proper inode locked
43 : * and configfs_dirent_lock locked, in that order.
44 : * This allows one to safely traverse configfs_dirent trees and symlinks without
45 : * having to lock inodes.
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()
50 : */
51 1 : DEFINE_SPINLOCK(configfs_dirent_lock);
52 :
53 : static void configfs_d_iput(struct dentry * dentry,
54 : struct inode * inode)
55 1 : {
56 3 : struct configfs_dirent * sd = dentry->d_fsdata;
57 :
58 2 : if (sd) {
59 7 : BUG_ON(sd->s_dentry != dentry);
60 1 : sd->s_dentry = NULL;
61 3 : configfs_put(sd);
62 : }
63 2 : iput(inode);
64 2 : }
65 :
66 : /*
67 : * We _must_ delete our dentries on last dput, as the chain-to-parent
68 : * behavior is required to clear the parents of default_groups.
69 : */
70 : static int configfs_d_delete(struct dentry *dentry)
71 : {
72 1 : return 1;
73 : }
74 :
75 1 : static const struct dentry_operations configfs_dentry_ops = {
76 : .d_iput = configfs_d_iput,
77 : /* simple_delete_dentry() isn't exported */
78 : .d_delete = configfs_d_delete,
79 : };
80 :
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 8 : }
149 :
150 : static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
151 : struct configfs_dirent *sd)
152 4 : {
153 : }
154 :
155 : static void
156 : configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
157 : {
158 1 : }
159 :
160 : static void
161 : configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
162 : {
163 2 : }
164 :
165 : #endif /* CONFIG_LOCKDEP */
166 :
167 : /*
168 : * Allocates a new configfs_dirent and links it to the parent configfs_dirent
169 : */
170 : static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd,
171 : void *element, int type)
172 : {
173 8 : struct configfs_dirent * sd;
174 8 :
175 32 : sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
176 24 : if (!sd)
177 24 : return ERR_PTR(-ENOMEM);
178 :
179 16 : atomic_set(&sd->s_count, 1);
180 16 : INIT_LIST_HEAD(&sd->s_links);
181 16 : INIT_LIST_HEAD(&sd->s_children);
182 8 : sd->s_element = element;
183 8 : sd->s_type = type;
184 16 : configfs_init_dirent_depth(sd);
185 16 : spin_lock(&configfs_dirent_lock);
186 16 : if (parent_sd->s_type & CONFIGFS_USET_DROPPING) {
187 16 : spin_unlock(&configfs_dirent_lock);
188 8 : kmem_cache_free(configfs_dir_cachep, sd);
189 24 : return ERR_PTR(-ENOENT);
190 : }
191 16 : list_add(&sd->s_sibling, &parent_sd->s_children);
192 16 : spin_unlock(&configfs_dirent_lock);
193 :
194 8 : return sd;
195 : }
196 :
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 : */
204 : static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
205 : const unsigned char *new)
206 2 : {
207 2 : struct configfs_dirent * sd;
208 2 :
209 22 : list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
210 14 : if (sd->s_element) {
211 12 : const unsigned char *existing = configfs_get_name(sd);
212 6 : if (strcmp(existing, new))
213 2 : continue;
214 : else
215 2 : return -EEXIST;
216 : }
217 : }
218 :
219 2 : return 0;
220 2 : }
221 :
222 :
223 : int configfs_make_dirent(struct configfs_dirent * parent_sd,
224 : struct dentry * dentry, void * element,
225 : umode_t mode, int type)
226 7 : {
227 7 : struct configfs_dirent * sd;
228 7 :
229 35 : sd = configfs_new_dirent(parent_sd, element, type);
230 28 : if (IS_ERR(sd))
231 21 : return PTR_ERR(sd);
232 :
233 7 : sd->s_mode = mode;
234 7 : sd->s_dentry = dentry;
235 14 : if (dentry) {
236 28 : dentry->d_fsdata = configfs_get(sd);
237 7 : dentry->d_op = &configfs_dentry_ops;
238 : }
239 :
240 14 : return 0;
241 : }
242 :
243 : static int init_dir(struct inode * inode)
244 : {
245 2 : inode->i_op = &configfs_dir_inode_operations;
246 2 : inode->i_fop = &configfs_dir_operations;
247 :
248 : /* directory inodes start off with i_nlink == 2 (for "." entry) */
249 4 : inc_nlink(inode);
250 2 : return 0;
251 : }
252 :
253 : static int configfs_init_file(struct inode * inode)
254 : {
255 1 : inode->i_size = PAGE_SIZE;
256 1 : inode->i_fop = &configfs_file_operations;
257 1 : return 0;
258 : }
259 :
260 : static int init_symlink(struct inode * inode)
261 : {
262 1 : inode->i_op = &configfs_symlink_inode_operations;
263 1 : return 0;
264 : }
265 :
266 : static int create_dir(struct config_item * k, struct dentry * p,
267 : struct dentry * d)
268 2 : {
269 2 : int error;
270 4 : umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
271 :
272 8 : error = configfs_dirent_exists(p->d_fsdata, d->d_name.name);
273 4 : if (!error)
274 10 : error = configfs_make_dirent(p->d_fsdata, d, k, mode,
275 : CONFIGFS_DIR | CONFIGFS_USET_CREATING);
276 8 : if (!error) {
277 16 : configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata);
278 12 : error = configfs_create(d, mode, init_dir);
279 4 : if (!error) {
280 4 : inc_nlink(p->d_inode);
281 2 : (d)->d_op = &configfs_dentry_ops;
282 : } else {
283 4 : struct configfs_dirent *sd = d->d_fsdata;
284 4 : if (sd) {
285 4 : spin_lock(&configfs_dirent_lock);
286 4 : list_del_init(&sd->s_sibling);
287 4 : spin_unlock(&configfs_dirent_lock);
288 6 : configfs_put(sd);
289 : }
290 : }
291 : }
292 10 : return error;
293 : }
294 :
295 :
296 : /**
297 : * configfs_create_dir - create a directory for an config_item.
298 : * @item: config_itemwe're creating directory for.
299 : * @dentry: config_item's dentry.
300 : *
301 : * Note: user-created entries won't be allowed under this new directory
302 : * until it is validated by configfs_dir_set_ready()
303 : */
304 :
305 : static int configfs_create_dir(struct config_item * item, struct dentry *dentry)
306 : {
307 2 : struct dentry * parent;
308 4 : int error = 0;
309 2 :
310 12 : BUG_ON(!item);
311 :
312 6 : if (item->ci_parent)
313 2 : parent = item->ci_parent->ci_dentry;
314 10 : else if (configfs_mount && configfs_mount->mnt_sb)
315 2 : parent = configfs_mount->mnt_sb->s_root;
316 : else
317 2 : return -EFAULT;
318 :
319 12 : error = create_dir(item,parent,dentry);
320 4 : if (!error)
321 2 : item->ci_dentry = dentry;
322 2 : return error;
323 : }
324 :
325 : /*
326 : * Allow userspace to create new entries under a new directory created with
327 : * configfs_create_dir(), and under all of its chidlren directories recursively.
328 : * @sd configfs_dirent of the new directory to validate
329 : *
330 : * Caller must hold configfs_dirent_lock.
331 : */
332 : static void configfs_dir_set_ready(struct configfs_dirent *sd)
333 : {
334 1 : struct configfs_dirent *child_sd;
335 1 :
336 2 : sd->s_type &= ~CONFIGFS_USET_CREATING;
337 10 : list_for_each_entry(child_sd, &sd->s_children, s_sibling)
338 5 : if (child_sd->s_type & CONFIGFS_USET_CREATING)
339 2 : configfs_dir_set_ready(child_sd);
340 : }
341 :
342 : /*
343 : * Check that a directory does not belong to a directory hierarchy being
344 1 : * attached and not validated yet.
345 : * @sd configfs_dirent of the directory to check
346 : *
347 : * @return non-zero iff the directory was validated
348 : *
349 : * Note: takes configfs_dirent_lock, so the result may change from false to true
350 : * in two consecutive calls, but never from true to false.
351 : */
352 : int configfs_dirent_is_ready(struct configfs_dirent *sd)
353 : {
354 5 : int ret;
355 :
356 10 : spin_lock(&configfs_dirent_lock);
357 5 : ret = !(sd->s_type & CONFIGFS_USET_CREATING);
358 10 : spin_unlock(&configfs_dirent_lock);
359 :
360 5 : return ret;
361 : }
362 :
363 : int configfs_create_link(struct configfs_symlink *sl,
364 : struct dentry *parent,
365 1 : struct dentry *dentry)
366 1 : {
367 2 : int err = 0;
368 1 : umode_t mode = S_IFLNK | S_IRWXUGO;
369 :
370 5 : err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
371 : CONFIGFS_ITEM_LINK);
372 2 : if (!err) {
373 6 : err = configfs_create(dentry, mode, init_symlink);
374 2 : if (!err)
375 1 : dentry->d_op = &configfs_dentry_ops;
376 : else {
377 2 : struct configfs_dirent *sd = dentry->d_fsdata;
378 2 : if (sd) {
379 2 : spin_lock(&configfs_dirent_lock);
380 2 : list_del_init(&sd->s_sibling);
381 2 : spin_unlock(&configfs_dirent_lock);
382 3 : configfs_put(sd);
383 : }
384 : }
385 : }
386 3 : return err;
387 : }
388 :
389 : static void remove_dir(struct dentry * d)
390 : {
391 30 : struct dentry * parent = dget(d->d_parent);
392 6 : struct configfs_dirent * sd;
393 6 :
394 12 : sd = d->d_fsdata;
395 12 : spin_lock(&configfs_dirent_lock);
396 12 : list_del_init(&sd->s_sibling);
397 12 : spin_unlock(&configfs_dirent_lock);
398 18 : configfs_put(sd);
399 18 : if (d->d_inode)
400 6 : simple_rmdir(parent->d_inode,d);
401 :
402 : pr_debug(" o %s removing done (%d)\n",d->d_name.name,
403 : atomic_read(&d->d_count));
404 :
405 6 : dput(parent);
406 6 : }
407 :
408 : /**
409 : * configfs_remove_dir - remove an config_item's directory.
410 : * @item: config_item we're removing.
411 : *
412 : * The only thing special about this is that we remove any files in
413 : * the directory before we remove the directory, and we've inlined
414 : * what used to be configfs_rmdir() below, instead of calling separately.
415 : *
416 : * Caller holds the mutex of the item's inode
417 : */
418 :
419 : static void configfs_remove_dir(struct config_item * item)
420 : {
421 30 : struct dentry * dentry = dget(item->ci_dentry);
422 6 :
423 12 : if (!dentry)
424 6 : return;
425 :
426 12 : remove_dir(dentry);
427 : /**
428 : * Drop reference from dget() on entrance.
429 : */
430 6 : dput(dentry);
431 6 : }
432 :
433 :
434 : /* attaches attribute's configfs_dirent to the dentry corresponding to the
435 : * attribute file
436 : */
437 : static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
438 : {
439 3 : struct configfs_attribute * attr = sd->s_element;
440 1 : int error;
441 1 :
442 4 : dentry->d_fsdata = configfs_get(sd);
443 1 : sd->s_dentry = dentry;
444 6 : error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
445 : configfs_init_file);
446 2 : if (error) {
447 3 : configfs_put(sd);
448 1 : return error;
449 : }
450 :
451 1 : dentry->d_op = &configfs_dentry_ops;
452 1 : d_rehash(dentry);
453 :
454 1 : return 0;
455 : }
456 :
457 : static struct dentry * configfs_lookup(struct inode *dir,
458 : struct dentry *dentry,
459 : struct nameidata *nd)
460 1 : {
461 3 : struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
462 1 : struct configfs_dirent * sd;
463 2 : int found = 0;
464 1 : int err;
465 1 :
466 1 : /*
467 1 : * Fake invisibility if dir belongs to a group/default groups hierarchy
468 1 : * being attached
469 1 : *
470 1 : * This forbids userspace to read/write attributes of items which may
471 1 : * not complete their initialization, since the dentries of the
472 : * attributes won't be instantiated.
473 : */
474 1 : err = -ENOENT;
475 4 : if (!configfs_dirent_is_ready(parent_sd))
476 1 : goto out;
477 :
478 10 : list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
479 5 : if (sd->s_type & CONFIGFS_NOT_PINNED) {
480 5 : const unsigned char * name = configfs_get_name(sd);
481 :
482 3 : if (strcmp(name, dentry->d_name.name))
483 1 : continue;
484 1 :
485 1 : found = 1;
486 3 : err = configfs_attach_attr(sd, dentry);
487 1 : break;
488 : }
489 : }
490 :
491 5 : if (!found) {
492 : /*
493 : * If it doesn't exist and it isn't a NOT_PINNED item,
494 : * it must be negative.
495 : */
496 4 : return simple_lookup(dir, dentry, nd);
497 : }
498 :
499 : out:
500 9 : return ERR_PTR(err);
501 : }
502 :
503 : /*
504 : * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
505 : * attributes and are removed by rmdir(). We recurse, setting
506 : * CONFIGFS_USET_DROPPING on all children that are candidates for
507 : * default detach.
508 : * If there is an error, the caller will reset the flags via
509 : * configfs_detach_rollback().
510 : */
511 : static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex)
512 : {
513 3 : struct configfs_dirent *parent_sd = dentry->d_fsdata;
514 1 : struct configfs_dirent *sd;
515 1 : int ret;
516 1 :
517 1 : /* Mark that we're trying to drop the group */
518 2 : parent_sd->s_type |= CONFIGFS_USET_DROPPING;
519 :
520 1 : ret = -EBUSY;
521 4 : if (!list_empty(&parent_sd->s_links))
522 1 : goto out;
523 :
524 1 : ret = 0;
525 10 : list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
526 8 : if (!sd->s_element ||
527 1 : (sd->s_type & CONFIGFS_NOT_PINNED))
528 1 : continue;
529 2 : if (sd->s_type & CONFIGFS_USET_DEFAULT) {
530 : /* Abort if racing with mkdir() */
531 3 : if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
532 4 : if (wait_mutex)
533 1 : *wait_mutex = &sd->s_dentry->d_inode->i_mutex;
534 1 : return -EAGAIN;
535 : }
536 :
537 : /*
538 : * Yup, recursive. If there's a problem, blame
539 : * deep nesting of default_groups
540 : */
541 1 : ret = configfs_detach_prep(sd->s_dentry, wait_mutex);
542 2 : if (!ret)
543 1 : continue;
544 : } else
545 1 : ret = -ENOTEMPTY;
546 :
547 2 : break;
548 2 : }
549 :
550 : out:
551 3 : return ret;
552 : }
553 :
554 : /*
555 : * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
556 : * set.
557 : */
558 : static void configfs_detach_rollback(struct dentry *dentry)
559 : {
560 3 : struct configfs_dirent *parent_sd = dentry->d_fsdata;
561 1 : struct configfs_dirent *sd;
562 1 :
563 2 : parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;
564 :
565 10 : list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
566 5 : if (sd->s_type & CONFIGFS_USET_DEFAULT)
567 2 : configfs_detach_rollback(sd->s_dentry);
568 : }
569 :
570 : static void detach_attrs(struct config_item * item)
571 : {
572 51 : struct dentry * dentry = dget(item->ci_dentry);
573 10 : struct configfs_dirent * parent_sd;
574 10 : struct configfs_dirent * sd, * tmp;
575 10 :
576 30 : if (!dentry)
577 20 : return;
578 10 :
579 10 : pr_debug("configfs %s: dropping attrs for dir\n",
580 : dentry->d_name.name);
581 :
582 20 : parent_sd = dentry->d_fsdata;
583 130 : list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
584 80 : if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
585 20 : continue;
586 20 : spin_lock(&configfs_dirent_lock);
587 20 : list_del_init(&sd->s_sibling);
588 20 : spin_unlock(&configfs_dirent_lock);
589 40 : configfs_drop_dentry(sd, dentry);
590 30 : configfs_put(sd);
591 : }
592 10 :
593 : /**
594 : * Drop reference from dget() on entrance.
595 : */
596 10 : dput(dentry);
597 10 : }
598 :
599 : static int populate_attrs(struct config_item *item)
600 : {
601 4 : struct config_item_type *t = item->ci_type;
602 2 : struct configfs_attribute *attr;
603 4 : int error = 0;
604 2 : int i;
605 :
606 4 : if (!t)
607 2 : return -EINVAL;
608 6 : if (t->ct_attrs) {
609 12 : for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
610 12 : if ((error = configfs_create_file(item, attr)))
611 4 : break;
612 : }
613 : }
614 :
615 14 : if (error)
616 18 : detach_attrs(item);
617 :
618 8 : return error;
619 : }
620 :
621 : static int configfs_attach_group(struct config_item *parent_item,
622 : struct config_item *item,
623 : struct dentry *dentry);
624 : static void configfs_detach_group(struct config_item *item);
625 :
626 : static void detach_groups(struct config_group *group)
627 : {
628 10 : struct dentry * dentry = dget(group->cg_item.ci_dentry);
629 2 : struct dentry *child;
630 2 : struct configfs_dirent *parent_sd;
631 2 : struct configfs_dirent *sd, *tmp;
632 2 :
633 6 : if (!dentry)
634 4 : return;
635 2 :
636 6 : parent_sd = dentry->d_fsdata;
637 26 : list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
638 16 : if (!sd->s_element ||
639 2 : !(sd->s_type & CONFIGFS_USET_DEFAULT))
640 2 : continue;
641 :
642 2 : child = sd->s_dentry;
643 :
644 2 : mutex_lock(&child->d_inode->i_mutex);
645 :
646 5 : configfs_detach_group(sd->s_element);
647 2 : child->d_inode->i_flags |= S_DEAD;
648 :
649 2 : mutex_unlock(&child->d_inode->i_mutex);
650 :
651 2 : d_delete(child);
652 2 : dput(child);
653 : }
654 2 :
655 : /**
656 : * Drop reference from dget() on entrance.
657 : */
658 2 : dput(dentry);
659 2 : }
660 :
661 : /*
662 : * This fakes mkdir(2) on a default_groups[] entry. It
663 : * creates a dentry, attachs it, and then does fixup
664 : * on the sd->s_type.
665 : *
666 : * We could, perhaps, tweak our parent's ->mkdir for a minute and
667 : * try using vfs_mkdir. Just a thought.
668 : */
669 : static int create_default_group(struct config_group *parent_group,
670 : struct config_group *group)
671 1 : {
672 1 : int ret;
673 1 : struct qstr name;
674 1 : struct configfs_dirent *sd;
675 1 : /* We trust the caller holds a reference to parent */
676 2 : struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
677 :
678 2 : if (!group->cg_item.ci_name)
679 1 : group->cg_item.ci_name = group->cg_item.ci_namebuf;
680 1 : name.name = group->cg_item.ci_name;
681 2 : name.len = strlen(name.name);
682 2 : name.hash = full_name_hash(name.name, name.len);
683 :
684 1 : ret = -ENOMEM;
685 1 : child = d_alloc(parent, &name);
686 2 : if (child) {
687 2 : d_add(child, NULL);
688 :
689 1 : ret = configfs_attach_group(&parent_group->cg_item,
690 : &group->cg_item, child);
691 2 : if (!ret) {
692 2 : sd = child->d_fsdata;
693 1 : sd->s_type |= CONFIGFS_USET_DEFAULT;
694 : } else {
695 1 : d_delete(child);
696 1 : dput(child);
697 : }
698 : }
699 :
700 2 : return ret;
701 : }
702 :
703 : static int populate_groups(struct config_group *group)
704 : {
705 1 : struct config_group *new_group;
706 2 : int ret = 0;
707 1 : int i;
708 :
709 3 : if (group->default_groups) {
710 5 : for (i = 0; group->default_groups[i]; i++) {
711 3 : new_group = group->default_groups[i];
712 1 :
713 3 : ret = create_default_group(group, new_group);
714 2 : if (ret) {
715 3 : detach_groups(group);
716 2 : break;
717 : }
718 : }
719 : }
720 :
721 3 : return ret;
722 : }
723 :
724 : /*
725 : * All of link_obj/unlink_obj/link_group/unlink_group require that
726 : * subsys->su_mutex is held.
727 : */
728 :
729 : static void unlink_obj(struct config_item *item)
730 : {
731 6 : struct config_group *group;
732 :
733 6 : group = item->ci_group;
734 12 : if (group) {
735 12 : list_del_init(&item->ci_entry);
736 :
737 6 : item->ci_group = NULL;
738 6 : item->ci_parent = NULL;
739 :
740 : /* Drop the reference for ci_entry */
741 12 : config_item_put(item);
742 :
743 : /* Drop the reference for ci_parent */
744 12 : config_group_put(group);
745 : }
746 12 : }
747 :
748 : static void link_obj(struct config_item *parent_item, struct config_item *item)
749 : {
750 2 : /*
751 : * Parent seems redundant with group, but it makes certain
752 : * traversals much nicer.
753 : */
754 2 : item->ci_parent = parent_item;
755 :
756 : /*
757 : * We hold a reference on the parent for the child's ci_parent
758 : * link.
759 : */
760 10 : item->ci_group = config_group_get(to_config_group(parent_item));
761 4 : list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
762 :
763 : /*
764 : * We hold a reference on the child for ci_entry on the parent's
765 : * cg_children
766 : */
767 4 : config_item_get(item);
768 2 : }
769 :
770 : static void unlink_group(struct config_group *group)
771 : {
772 2 : int i;
773 2 : struct config_group *new_group;
774 :
775 6 : if (group->default_groups) {
776 10 : for (i = 0; group->default_groups[i]; i++) {
777 4 : new_group = group->default_groups[i];
778 6 : unlink_group(new_group);
779 : }
780 : }
781 :
782 4 : group->cg_subsys = NULL;
783 12 : unlink_obj(&group->cg_item);
784 2 : }
785 :
786 : static void link_group(struct config_group *parent_group, struct config_group *group)
787 : {
788 1 : int i;
789 1 : struct config_group *new_group;
790 2 : struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
791 1 :
792 2 : link_obj(&parent_group->cg_item, &group->cg_item);
793 :
794 3 : if (parent_group->cg_subsys)
795 1 : subsys = parent_group->cg_subsys;
796 4 : else if (configfs_is_root(&parent_group->cg_item))
797 2 : subsys = to_configfs_subsystem(group);
798 : else
799 2 : BUG();
800 3 : group->cg_subsys = subsys;
801 :
802 9 : if (group->default_groups) {
803 9 : for (i = 0; group->default_groups[i]; i++) {
804 2 : new_group = group->default_groups[i];
805 3 : link_group(group, new_group);
806 : }
807 : }
808 : }
809 :
810 : /*
811 4 : * The goal is that configfs_attach_item() (and
812 : * configfs_attach_group()) can be called from either the VFS or this
813 : * module. That is, they assume that the items have been created,
814 : * the dentry allocated, and the dcache is all ready to go.
815 : *
816 : * If they fail, they must clean up after themselves as if they
817 : * had never been called. The caller (VFS or local function) will
818 : * handle cleaning up the dcache bits.
819 : *
820 : * configfs_detach_group() and configfs_detach_item() behave similarly on
821 : * the way out. They assume that the proper semaphores are held, they
822 : * clean up the configfs items, and they expect their callers will
823 : * handle the dcache bits.
824 : */
825 : static int configfs_attach_item(struct config_item *parent_item,
826 : struct config_item *item,
827 : struct dentry *dentry)
828 2 : {
829 : int ret;
830 :
831 6 : ret = configfs_create_dir(item, dentry);
832 4 : if (!ret) {
833 10 : ret = populate_attrs(item);
834 4 : if (ret) {
835 : /*
836 : * We are going to remove an inode and its dentry but
837 : * the VFS may already have hit and used them. Thus,
838 : * we must lock them as rmdir() would.
839 : */
840 2 : mutex_lock(&dentry->d_inode->i_mutex);
841 6 : configfs_remove_dir(item);
842 2 : dentry->d_inode->i_flags |= S_DEAD;
843 2 : mutex_unlock(&dentry->d_inode->i_mutex);
844 2 : d_delete(dentry);
845 : }
846 : }
847 :
848 6 : return ret;
849 : }
850 :
851 : /* Caller holds the mutex of the item's inode */
852 : static void configfs_detach_item(struct config_item *item)
853 : {
854 12 : detach_attrs(item);
855 12 : configfs_remove_dir(item);
856 4 : }
857 :
858 : static int configfs_attach_group(struct config_item *parent_item,
859 : struct config_item *item,
860 : struct dentry *dentry)
861 1 : {
862 1 : int ret;
863 1 : struct configfs_dirent *sd;
864 :
865 4 : ret = configfs_attach_item(parent_item, item, dentry);
866 2 : if (!ret) {
867 2 : sd = dentry->d_fsdata;
868 1 : sd->s_type |= CONFIGFS_USET_DIR;
869 :
870 : /*
871 : * FYI, we're faking mkdir in populate_groups()
872 : * We must lock the group's inode to avoid races with the VFS
873 : * which can already hit the inode and try to add/remove entries
874 : * under it.
875 : *
876 : * We must also lock the inode to remove it safely in case of
877 : * error, as rmdir() would.
878 : */
879 1 : mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
880 2 : configfs_adjust_dir_dirent_depth_before_populate(sd);
881 6 : ret = populate_groups(to_config_group(item));
882 2 : if (ret) {
883 2 : configfs_detach_item(item);
884 1 : dentry->d_inode->i_flags |= S_DEAD;
885 : }
886 4 : configfs_adjust_dir_dirent_depth_after_populate(sd);
887 1 : mutex_unlock(&dentry->d_inode->i_mutex);
888 2 : if (ret)
889 1 : d_delete(dentry);
890 : }
891 :
892 2 : return ret;
893 : }
894 :
895 : /* Caller holds the mutex of the group's inode */
896 : static void configfs_detach_group(struct config_item *item)
897 : {
898 10 : detach_groups(to_config_group(item));
899 4 : configfs_detach_item(item);
900 2 : }
901 :
902 : /*
903 : * After the item has been detached from the filesystem view, we are
904 : * ready to tear it out of the hierarchy. Notify the client before
905 : * we do that so they can perform any cleanup that requires
906 : * navigating the hierarchy. A client does not need to provide this
907 : * callback. The subsystem semaphore MUST be held by the caller, and
908 : * references must be valid for both items. It also assumes the
909 : * caller has validated ci_type.
910 : */
911 : static void client_disconnect_notify(struct config_item *parent_item,
912 : struct config_item *item)
913 8 : {
914 8 : struct config_item_type *type;
915 8 :
916 8 : type = parent_item->ci_type;
917 48 : BUG_ON(!type);
918 :
919 48 : if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
920 24 : type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
921 16 : item);
922 : }
923 :
924 : /*
925 : * Drop the initial reference from make_item()/make_group()
926 : * This function assumes that reference is held on item
927 : * and that item holds a valid reference to the parent. Also, it
928 : * assumes the caller has validated ci_type.
929 : */
930 : static void client_drop_item(struct config_item *parent_item,
931 : struct config_item *item)
932 4 : {
933 4 : struct config_item_type *type;
934 4 :
935 4 : type = parent_item->ci_type;
936 24 : BUG_ON(!type);
937 :
938 : /*
939 : * If ->drop_item() exists, it is responsible for the
940 : * config_item_put().
941 : */
942 24 : if (type->ct_group_ops && type->ct_group_ops->drop_item)
943 12 : type->ct_group_ops->drop_item(to_config_group(parent_item),
944 : item);
945 : else
946 8 : config_item_put(item);
947 8 : }
948 :
949 : #ifdef DEBUG
950 : static void configfs_dump_one(struct configfs_dirent *sd, int level)
951 : {
952 : printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd));
953 :
954 : #define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type);
955 : type_print(CONFIGFS_ROOT);
956 : type_print(CONFIGFS_DIR);
957 : type_print(CONFIGFS_ITEM_ATTR);
958 : type_print(CONFIGFS_ITEM_LINK);
959 : type_print(CONFIGFS_USET_DIR);
960 : type_print(CONFIGFS_USET_DEFAULT);
961 : type_print(CONFIGFS_USET_DROPPING);
962 : #undef type_print
963 : }
964 :
965 : static int configfs_dump(struct configfs_dirent *sd, int level)
966 : {
967 : struct configfs_dirent *child_sd;
968 : int ret = 0;
969 :
970 : configfs_dump_one(sd, level);
971 :
972 : if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
973 : return 0;
974 :
975 : list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
976 : ret = configfs_dump(child_sd, level + 2);
977 : if (ret)
978 : break;
979 : }
980 :
981 : return ret;
982 : }
983 : #endif
984 :
985 :
986 : /*
987 : * configfs_depend_item() and configfs_undepend_item()
988 : *
989 : * WARNING: Do not call these from a configfs callback!
990 : *
991 : * This describes these functions and their helpers.
992 : *
993 : * Allow another kernel system to depend on a config_item. If this
994 : * happens, the item cannot go away until the dependant can live without
995 : * it. The idea is to give client modules as simple an interface as
996 : * possible. When a system asks them to depend on an item, they just
997 : * call configfs_depend_item(). If the item is live and the client
998 : * driver is in good shape, we'll happily do the work for them.
999 : *
1000 : * Why is the locking complex? Because configfs uses the VFS to handle
1001 : * all locking, but this function is called outside the normal
1002 : * VFS->configfs path. So it must take VFS locks to prevent the
1003 : * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
1004 : * why you can't call these functions underneath configfs callbacks.
1005 : *
1006 : * Note, btw, that this can be called at *any* time, even when a configfs
1007 : * subsystem isn't registered, or when configfs is loading or unloading.
1008 : * Just like configfs_register_subsystem(). So we take the same
1009 : * precautions. We pin the filesystem. We lock configfs_dirent_lock.
1010 : * If we can find the target item in the
1011 : * configfs tree, it must be part of the subsystem tree as well, so we
1012 : * do not need the subsystem semaphore. Holding configfs_dirent_lock helps
1013 : * locking out mkdir() and rmdir(), who might be racing us.
1014 : */
1015 :
1016 : /*
1017 : * configfs_depend_prep()
1018 : *
1019 : * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
1020 : * attributes. This is similar but not the same to configfs_detach_prep().
1021 : * Note that configfs_detach_prep() expects the parent to be locked when it
1022 : * is called, but we lock the parent *inside* configfs_depend_prep(). We
1023 : * do that so we can unlock it if we find nothing.
1024 : *
1025 : * Here we do a depth-first search of the dentry hierarchy looking for
1026 : * our object.
1027 : * We deliberately ignore items tagged as dropping since they are virtually
1028 : * dead, as well as items in the middle of attachment since they virtually
1029 : * do not exist yet. This completes the locking out of racing mkdir() and
1030 : * rmdir().
1031 : * Note: subdirectories in the middle of attachment start with s_type =
1032 : * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When
1033 : * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of
1034 : * s_type is in configfs_new_dirent(), which has configfs_dirent_lock.
1035 : *
1036 : * If the target is not found, -ENOENT is bubbled up.
1037 : *
1038 : * This adds a requirement that all config_items be unique!
1039 : *
1040 : * This is recursive. There isn't
1041 : * much on the stack, though, so folks that need this function - be careful
1042 : * about your stack! Patches will be accepted to make it iterative.
1043 : */
1044 : static int configfs_depend_prep(struct dentry *origin,
1045 : struct config_item *target)
1046 0 : {
1047 0 : struct configfs_dirent *child_sd, *sd = origin->d_fsdata;
1048 0 : int ret = 0;
1049 0 :
1050 0 : BUG_ON(!origin || !sd);
1051 0 :
1052 0 : if (sd->s_element == target) /* Boo-yah */
1053 0 : goto out;
1054 :
1055 0 : list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
1056 0 : if ((child_sd->s_type & CONFIGFS_DIR) &&
1057 0 : !(child_sd->s_type & CONFIGFS_USET_DROPPING) &&
1058 : !(child_sd->s_type & CONFIGFS_USET_CREATING)) {
1059 0 : ret = configfs_depend_prep(child_sd->s_dentry,
1060 : target);
1061 0 : if (!ret)
1062 0 : goto out; /* Child path boo-yah */
1063 : }
1064 : }
1065 :
1066 : /* We looped all our children and didn't find target */
1067 0 : ret = -ENOENT;
1068 0 :
1069 : out:
1070 0 : return ret;
1071 : }
1072 :
1073 : int configfs_depend_item(struct configfs_subsystem *subsys,
1074 : struct config_item *target)
1075 0 : {
1076 0 : int ret;
1077 0 : struct configfs_dirent *p, *root_sd, *subsys_sd = NULL;
1078 0 : struct config_item *s_item = &subsys->su_group.cg_item;
1079 0 :
1080 0 : /*
1081 0 : * Pin the configfs filesystem. This means we can safely access
1082 : * the root of the configfs filesystem.
1083 : */
1084 0 : ret = configfs_pin_fs();
1085 0 : if (ret)
1086 0 : return ret;
1087 :
1088 : /*
1089 : * Next, lock the root directory. We're going to check that the
1090 : * subsystem is really registered, and so we need to lock out
1091 : * configfs_[un]register_subsystem().
1092 : */
1093 0 : mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1094 :
1095 0 : root_sd = configfs_sb->s_root->d_fsdata;
1096 :
1097 0 : list_for_each_entry(p, &root_sd->s_children, s_sibling) {
1098 0 : if (p->s_type & CONFIGFS_DIR) {
1099 0 : if (p->s_element == s_item) {
1100 0 : subsys_sd = p;
1101 0 : break;
1102 : }
1103 0 : }
1104 : }
1105 :
1106 0 : if (!subsys_sd) {
1107 0 : ret = -ENOENT;
1108 0 : goto out_unlock_fs;
1109 : }
1110 :
1111 : /* Ok, now we can trust subsys/s_item */
1112 :
1113 0 : spin_lock(&configfs_dirent_lock);
1114 : /* Scan the tree, return 0 if found */
1115 0 : ret = configfs_depend_prep(subsys_sd->s_dentry, target);
1116 0 : if (ret)
1117 0 : goto out_unlock_dirent_lock;
1118 :
1119 : /*
1120 : * We are sure that the item is not about to be removed by rmdir(), and
1121 : * not in the middle of attachment by mkdir().
1122 : */
1123 0 : p = target->ci_dentry->d_fsdata;
1124 0 : p->s_dependent_count += 1;
1125 0 :
1126 : out_unlock_dirent_lock:
1127 0 : spin_unlock(&configfs_dirent_lock);
1128 : out_unlock_fs:
1129 0 : mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1130 :
1131 : /*
1132 : * If we succeeded, the fs is pinned via other methods. If not,
1133 : * we're done with it anyway. So release_fs() is always right.
1134 : */
1135 0 : configfs_release_fs();
1136 :
1137 0 : return ret;
1138 : }
1139 : EXPORT_SYMBOL(configfs_depend_item);
1140 :
1141 : /*
1142 : * Release the dependent linkage. This is much simpler than
1143 : * configfs_depend_item() because we know that that the client driver is
1144 : * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
1145 : */
1146 : void configfs_undepend_item(struct configfs_subsystem *subsys,
1147 : struct config_item *target)
1148 0 : {
1149 0 : struct configfs_dirent *sd;
1150 :
1151 : /*
1152 : * Since we can trust everything is pinned, we just need
1153 : * configfs_dirent_lock.
1154 : */
1155 0 : spin_lock(&configfs_dirent_lock);
1156 :
1157 0 : sd = target->ci_dentry->d_fsdata;
1158 0 : BUG_ON(sd->s_dependent_count < 1);
1159 :
1160 0 : sd->s_dependent_count -= 1;
1161 :
1162 : /*
1163 : * After this unlock, we cannot trust the item to stay alive!
1164 : * DO NOT REFERENCE item after this unlock.
1165 : */
1166 0 : spin_unlock(&configfs_dirent_lock);
1167 0 : }
1168 : EXPORT_SYMBOL(configfs_undepend_item);
1169 :
1170 : static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1171 : {
1172 2 : int ret = 0;
1173 2 : int module_got = 0;
1174 2 : struct config_group *group = NULL;
1175 2 : struct config_item *item = NULL;
1176 1 : struct config_item *parent_item;
1177 1 : struct configfs_subsystem *subsys;
1178 1 : struct configfs_dirent *sd;
1179 1 : struct config_item_type *type;
1180 3 : struct module *subsys_owner = NULL, *new_item_owner = NULL;
1181 1 : char *name;
1182 1 :
1183 5 : if (dentry->d_parent == configfs_sb->s_root) {
1184 2 : ret = -EPERM;
1185 2 : goto out;
1186 1 : }
1187 1 :
1188 3 : sd = dentry->d_parent->d_fsdata;
1189 1 :
1190 1 : /*
1191 1 : * Fake invisibility if dir belongs to a group/default groups hierarchy
1192 1 : * being attached
1193 1 : */
1194 5 : if (!configfs_dirent_is_ready(sd)) {
1195 2 : ret = -ENOENT;
1196 2 : goto out;
1197 1 : }
1198 :
1199 2 : if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1200 1 : ret = -EPERM;
1201 1 : goto out;
1202 : }
1203 :
1204 : /* Get a working ref for the duration of this function */
1205 2 : parent_item = configfs_get_config_item(dentry->d_parent);
1206 1 : type = parent_item->ci_type;
1207 3 : subsys = to_config_group(parent_item)->cg_subsys;
1208 6 : BUG_ON(!subsys);
1209 :
1210 11 : if (!type || !type->ct_group_ops ||
1211 : (!type->ct_group_ops->make_group &&
1212 : !type->ct_group_ops->make_item)) {
1213 1 : ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1214 1 : goto out_put;
1215 : }
1216 :
1217 : /*
1218 : * The subsystem may belong to a different module than the item
1219 : * being created. We don't want to safely pin the new item but
1220 : * fail to pin the subsystem it sits under.
1221 : */
1222 2 : if (!subsys->su_group.cg_item.ci_type) {
1223 1 : ret = -EINVAL;
1224 1 : goto out_put;
1225 : }
1226 1 : subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1227 4 : if (!try_module_get(subsys_owner)) {
1228 1 : ret = -EINVAL;
1229 1 : goto out_put;
1230 : }
1231 :
1232 3 : name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1233 2 : if (!name) {
1234 1 : ret = -ENOMEM;
1235 1 : goto out_subsys_put;
1236 : }
1237 :
1238 1 : snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1239 :
1240 1 : mutex_lock(&subsys->su_mutex);
1241 3 : if (type->ct_group_ops->make_group) {
1242 3 : group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
1243 2 : if (!group)
1244 3 : group = ERR_PTR(-ENOMEM);
1245 6 : if (!IS_ERR(group)) {
1246 7 : link_group(to_config_group(parent_item), group);
1247 1 : item = &group->cg_item;
1248 : } else
1249 3 : ret = PTR_ERR(group);
1250 : } else {
1251 3 : item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
1252 2 : if (!item)
1253 3 : item = ERR_PTR(-ENOMEM);
1254 6 : if (!IS_ERR(item))
1255 2 : link_obj(parent_item, item);
1256 : else
1257 3 : ret = PTR_ERR(item);
1258 : }
1259 4 : mutex_unlock(&subsys->su_mutex);
1260 :
1261 4 : kfree(name);
1262 8 : if (ret) {
1263 : /*
1264 : * If ret != 0, then link_obj() was never called.
1265 : * There are no extra references to clean up.
1266 : */
1267 4 : goto out_subsys_put;
1268 : }
1269 :
1270 : /*
1271 : * link_obj() has been called (via link_group() for groups).
1272 : * From here on out, errors must clean that up.
1273 : */
1274 :
1275 4 : type = item->ci_type;
1276 8 : if (!type) {
1277 4 : ret = -EINVAL;
1278 4 : goto out_unlink;
1279 : }
1280 :
1281 4 : new_item_owner = type->ct_owner;
1282 10 : if (!try_module_get(new_item_owner)) {
1283 1 : ret = -EINVAL;
1284 1 : goto out_unlink;
1285 : }
1286 :
1287 : /*
1288 : * I hate doing it this way, but if there is
1289 : * an error, module_put() probably should
1290 : * happen after any cleanup.
1291 : */
1292 1 : module_got = 1;
1293 :
1294 : /*
1295 : * Make racing rmdir() fail if it did not tag parent with
1296 : * CONFIGFS_USET_DROPPING
1297 : * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will
1298 : * fail and let rmdir() terminate correctly
1299 : */
1300 2 : spin_lock(&configfs_dirent_lock);
1301 : /* This will make configfs_detach_prep() fail */
1302 1 : sd->s_type |= CONFIGFS_USET_IN_MKDIR;
1303 2 : spin_unlock(&configfs_dirent_lock);
1304 :
1305 2 : if (group)
1306 3 : ret = configfs_attach_group(parent_item, item, dentry);
1307 : else
1308 4 : ret = configfs_attach_item(parent_item, item, dentry);
1309 :
1310 4 : spin_lock(&configfs_dirent_lock);
1311 1 : sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
1312 2 : if (!ret)
1313 3 : configfs_dir_set_ready(dentry->d_fsdata);
1314 4 : spin_unlock(&configfs_dirent_lock);
1315 :
1316 1 : out_unlink:
1317 12 : if (ret) {
1318 : /* Tear down everything we built up */
1319 6 : mutex_lock(&subsys->su_mutex);
1320 :
1321 18 : client_disconnect_notify(parent_item, item);
1322 2 : if (group)
1323 2 : unlink_group(group);
1324 : else
1325 3 : unlink_obj(item);
1326 6 : client_drop_item(parent_item, item);
1327 :
1328 1 : mutex_unlock(&subsys->su_mutex);
1329 :
1330 2 : if (module_got)
1331 2 : module_put(new_item_owner);
1332 : }
1333 :
1334 : out_subsys_put:
1335 18 : if (ret)
1336 18 : module_put(subsys_owner);
1337 :
1338 : out_put:
1339 8 : /*
1340 : * link_obj()/link_group() took a reference from child->parent,
1341 10 : * so the parent is safely pinned. We can drop our working
1342 : * reference.
1343 : */
1344 24 : config_item_put(parent_item);
1345 :
1346 1 : out:
1347 3 : return ret;
1348 : }
1349 :
1350 : static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1351 : {
1352 1 : struct config_item *parent_item;
1353 1 : struct config_item *item;
1354 1 : struct configfs_subsystem *subsys;
1355 1 : struct configfs_dirent *sd;
1356 3 : struct module *subsys_owner = NULL, *dead_item_owner = NULL;
1357 1 : int ret;
1358 1 :
1359 5 : if (dentry->d_parent == configfs_sb->s_root)
1360 2 : return -EPERM;
1361 1 :
1362 3 : sd = dentry->d_fsdata;
1363 3 : if (sd->s_type & CONFIGFS_USET_DEFAULT)
1364 1 : return -EPERM;
1365 :
1366 : /* Get a working ref until we have the child */
1367 2 : parent_item = configfs_get_config_item(dentry->d_parent);
1368 3 : subsys = to_config_group(parent_item)->cg_subsys;
1369 6 : BUG_ON(!subsys);
1370 :
1371 3 : if (!parent_item->ci_type) {
1372 2 : config_item_put(parent_item);
1373 1 : return -EINVAL;
1374 : }
1375 :
1376 : /* configfs_mkdir() shouldn't have allowed this */
1377 6 : BUG_ON(!subsys->su_group.cg_item.ci_type);
1378 1 : subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1379 1 :
1380 : /*
1381 : * Ensure that no racing symlink() will make detach_prep() fail while
1382 : * the new link is temporarily attached
1383 : */
1384 : do {
1385 : struct mutex *wait_mutex;
1386 :
1387 1 : mutex_lock(&configfs_symlink_mutex);
1388 2 : spin_lock(&configfs_dirent_lock);
1389 : /*
1390 : * Here's where we check for dependents. We're protected by
1391 : * configfs_dirent_lock.
1392 : * If no dependent, atomically tag the item as dropping.
1393 : */
1394 6 : ret = sd->s_dependent_count ? -EBUSY : 0;
1395 2 : if (!ret) {
1396 4 : ret = configfs_detach_prep(dentry, &wait_mutex);
1397 2 : if (ret)
1398 2 : configfs_detach_rollback(dentry);
1399 : }
1400 6 : spin_unlock(&configfs_dirent_lock);
1401 1 : mutex_unlock(&configfs_symlink_mutex);
1402 :
1403 2 : if (ret) {
1404 2 : if (ret != -EAGAIN) {
1405 2 : config_item_put(parent_item);
1406 1 : return ret;
1407 : }
1408 :
1409 : /* Wait until the racing operation terminates */
1410 1 : mutex_lock(wait_mutex);
1411 1 : mutex_unlock(wait_mutex);
1412 : }
1413 2 : } while (ret == -EAGAIN);
1414 :
1415 1 : /* Get a working ref for the duration of this function */
1416 2 : item = configfs_get_config_item(dentry);
1417 :
1418 : /* Drop reference from above, item already holds one. */
1419 2 : config_item_put(parent_item);
1420 :
1421 3 : if (item->ci_type)
1422 1 : dead_item_owner = item->ci_type->ct_owner;
1423 :
1424 2 : if (sd->s_type & CONFIGFS_USET_DIR) {
1425 2 : configfs_detach_group(item);
1426 :
1427 1 : mutex_lock(&subsys->su_mutex);
1428 3 : client_disconnect_notify(parent_item, item);
1429 4 : unlink_group(to_config_group(item));
1430 : } else {
1431 2 : configfs_detach_item(item);
1432 :
1433 1 : mutex_lock(&subsys->su_mutex);
1434 3 : client_disconnect_notify(parent_item, item);
1435 3 : unlink_obj(item);
1436 : }
1437 :
1438 6 : client_drop_item(parent_item, item);
1439 1 : mutex_unlock(&subsys->su_mutex);
1440 :
1441 : /* Drop our reference from above */
1442 2 : config_item_put(item);
1443 :
1444 2 : module_put(dead_item_owner);
1445 2 : module_put(subsys_owner);
1446 :
1447 1 : return 0;
1448 : }
1449 :
1450 1 : const struct inode_operations configfs_dir_inode_operations = {
1451 : .mkdir = configfs_mkdir,
1452 : .rmdir = configfs_rmdir,
1453 : .symlink = configfs_symlink,
1454 : .unlink = configfs_unlink,
1455 : .lookup = configfs_lookup,
1456 : .setattr = configfs_setattr,
1457 : };
1458 :
1459 : #if 0
1460 : int configfs_rename_dir(struct config_item * item, const char *new_name)
1461 : {
1462 : int error = 0;
1463 : struct dentry * new_dentry, * parent;
1464 :
1465 : if (!strcmp(config_item_name(item), new_name))
1466 : return -EINVAL;
1467 :
1468 : if (!item->parent)
1469 : return -EINVAL;
1470 :
1471 : down_write(&configfs_rename_sem);
1472 : parent = item->parent->dentry;
1473 :
1474 : mutex_lock(&parent->d_inode->i_mutex);
1475 :
1476 : new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1477 : if (!IS_ERR(new_dentry)) {
1478 : if (!new_dentry->d_inode) {
1479 : error = config_item_set_name(item, "%s", new_name);
1480 : if (!error) {
1481 : d_add(new_dentry, NULL);
1482 : d_move(item->dentry, new_dentry);
1483 : }
1484 : else
1485 : d_delete(new_dentry);
1486 : } else
1487 : error = -EEXIST;
1488 : dput(new_dentry);
1489 : }
1490 : mutex_unlock(&parent->d_inode->i_mutex);
1491 : up_write(&configfs_rename_sem);
1492 :
1493 : return error;
1494 : }
1495 : #endif
1496 :
1497 : static int configfs_dir_open(struct inode *inode, struct file *file)
1498 : {
1499 2 : struct dentry * dentry = file->f_path.dentry;
1500 3 : struct configfs_dirent * parent_sd = dentry->d_fsdata;
1501 1 : int err;
1502 1 :
1503 2 : mutex_lock(&dentry->d_inode->i_mutex);
1504 1 : /*
1505 1 : * Fake invisibility if dir belongs to a group/default groups hierarchy
1506 : * being attached
1507 : */
1508 1 : err = -ENOENT;
1509 4 : if (configfs_dirent_is_ready(parent_sd)) {
1510 5 : file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
1511 5 : if (IS_ERR(file->private_data))
1512 4 : err = PTR_ERR(file->private_data);
1513 : else
1514 1 : err = 0;
1515 : }
1516 3 : mutex_unlock(&dentry->d_inode->i_mutex);
1517 :
1518 3 : return err;
1519 : }
1520 :
1521 : static int configfs_dir_close(struct inode *inode, struct file *file)
1522 : {
1523 2 : struct dentry * dentry = file->f_path.dentry;
1524 3 : struct configfs_dirent * cursor = file->private_data;
1525 :
1526 1 : mutex_lock(&dentry->d_inode->i_mutex);
1527 2 : spin_lock(&configfs_dirent_lock);
1528 2 : list_del_init(&cursor->s_sibling);
1529 2 : spin_unlock(&configfs_dirent_lock);
1530 1 : mutex_unlock(&dentry->d_inode->i_mutex);
1531 :
1532 2 : release_configfs_dirent(cursor);
1533 :
1534 1 : return 0;
1535 : }
1536 :
1537 : /* Relationship between s_mode and the DT_xxx types */
1538 : static inline unsigned char dt_type(struct configfs_dirent *sd)
1539 : {
1540 2 : return (sd->s_mode >> 12) & 15;
1541 : }
1542 :
1543 : static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
1544 : {
1545 1 : struct dentry *dentry = filp->f_path.dentry;
1546 2 : struct configfs_dirent * parent_sd = dentry->d_fsdata;
1547 2 : struct configfs_dirent *cursor = filp->private_data;
1548 1 : struct list_head *p, *q = &cursor->s_sibling;
1549 : ino_t ino;
1550 3 : int i = filp->f_pos;
1551 1 :
1552 1 : switch (i) {
1553 4 : case 0:
1554 2 : ino = dentry->d_inode->i_ino;
1555 4 : if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1556 2 : break;
1557 2 : filp->f_pos++;
1558 2 : i++;
1559 2 : /* fallthrough */
1560 4 : case 1:
1561 3 : ino = parent_ino(dentry);
1562 4 : if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1563 2 : break;
1564 2 : filp->f_pos++;
1565 2 : i++;
1566 2 : /* fallthrough */
1567 1 : default:
1568 5 : if (filp->f_pos == 2) {
1569 4 : spin_lock(&configfs_dirent_lock);
1570 2 : list_move(q, &parent_sd->s_children);
1571 2 : spin_unlock(&configfs_dirent_lock);
1572 : }
1573 10 : for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
1574 3 : struct configfs_dirent *next;
1575 1 : const char * name;
1576 : int len;
1577 :
1578 2 : next = list_entry(p, struct configfs_dirent,
1579 : s_sibling);
1580 4 : if (!next->s_element)
1581 1 : continue;
1582 1 :
1583 4 : name = configfs_get_name(next);
1584 2 : len = strlen(name);
1585 3 : if (next->s_dentry)
1586 1 : ino = next->s_dentry->d_inode->i_ino;
1587 : else
1588 1 : ino = iunique(configfs_sb, 2);
1589 :
1590 5 : if (filldir(dirent, name, len, filp->f_pos, ino,
1591 : dt_type(next)) < 0)
1592 1 : return 0;
1593 :
1594 2 : spin_lock(&configfs_dirent_lock);
1595 2 : list_move(q, p);
1596 2 : spin_unlock(&configfs_dirent_lock);
1597 1 : p = q;
1598 1 : filp->f_pos++;
1599 : }
1600 1 : }
1601 3 : return 0;
1602 : }
1603 :
1604 : static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin)
1605 : {
1606 2 : struct dentry * dentry = file->f_path.dentry;
1607 1 :
1608 2 : mutex_lock(&dentry->d_inode->i_mutex);
1609 1 : switch (origin) {
1610 4 : case 1:
1611 2 : offset += file->f_pos;
1612 5 : case 0:
1613 2 : if (offset >= 0)
1614 1 : break;
1615 1 : default:
1616 2 : mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
1617 1 : return -EINVAL;
1618 1 : }
1619 2 : if (offset != file->f_pos) {
1620 1 : file->f_pos = offset;
1621 2 : if (file->f_pos >= 2) {
1622 2 : struct configfs_dirent *sd = dentry->d_fsdata;
1623 2 : struct configfs_dirent *cursor = file->private_data;
1624 : struct list_head *p;
1625 1 : loff_t n = file->f_pos - 2;
1626 :
1627 2 : spin_lock(&configfs_dirent_lock);
1628 2 : list_del(&cursor->s_sibling);
1629 1 : p = sd->s_children.next;
1630 5 : while (n && p != &sd->s_children) {
1631 1 : struct configfs_dirent *next;
1632 3 : next = list_entry(p, struct configfs_dirent,
1633 : s_sibling);
1634 3 : if (next->s_element)
1635 1 : n--;
1636 1 : p = p->next;
1637 1 : }
1638 2 : list_add_tail(&cursor->s_sibling, p);
1639 2 : spin_unlock(&configfs_dirent_lock);
1640 : }
1641 : }
1642 2 : mutex_unlock(&dentry->d_inode->i_mutex);
1643 2 : return offset;
1644 : }
1645 :
1646 1 : const struct file_operations configfs_dir_operations = {
1647 : .open = configfs_dir_open,
1648 : .release = configfs_dir_close,
1649 : .llseek = configfs_dir_lseek,
1650 : .read = generic_read_dir,
1651 : .readdir = configfs_readdir,
1652 : };
1653 :
1654 : int configfs_register_subsystem(struct configfs_subsystem *subsys)
1655 : {
1656 0 : int err;
1657 0 : struct config_group *group = &subsys->su_group;
1658 0 : struct qstr name;
1659 0 : struct dentry *dentry;
1660 0 : struct configfs_dirent *sd;
1661 0 :
1662 0 : err = configfs_pin_fs();
1663 0 : if (err)
1664 0 : return err;
1665 :
1666 0 : if (!group->cg_item.ci_name)
1667 0 : group->cg_item.ci_name = group->cg_item.ci_namebuf;
1668 :
1669 0 : sd = configfs_sb->s_root->d_fsdata;
1670 0 : link_group(to_config_group(sd->s_element), group);
1671 :
1672 0 : mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1673 : I_MUTEX_PARENT);
1674 :
1675 0 : name.name = group->cg_item.ci_name;
1676 0 : name.len = strlen(name.name);
1677 0 : name.hash = full_name_hash(name.name, name.len);
1678 :
1679 0 : err = -ENOMEM;
1680 0 : dentry = d_alloc(configfs_sb->s_root, &name);
1681 0 : if (dentry) {
1682 0 : d_add(dentry, NULL);
1683 :
1684 0 : err = configfs_attach_group(sd->s_element, &group->cg_item,
1685 : dentry);
1686 0 : if (err) {
1687 0 : d_delete(dentry);
1688 0 : dput(dentry);
1689 : } else {
1690 0 : spin_lock(&configfs_dirent_lock);
1691 0 : configfs_dir_set_ready(dentry->d_fsdata);
1692 0 : spin_unlock(&configfs_dirent_lock);
1693 : }
1694 : }
1695 :
1696 0 : mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1697 :
1698 0 : if (err) {
1699 0 : unlink_group(group);
1700 0 : configfs_release_fs();
1701 : }
1702 :
1703 0 : return err;
1704 : }
1705 :
1706 : void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1707 : {
1708 0 : struct config_group *group = &subsys->su_group;
1709 0 : struct dentry *dentry = group->cg_item.ci_dentry;
1710 0 :
1711 0 : if (dentry->d_parent != configfs_sb->s_root) {
1712 0 : printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n");
1713 0 : return;
1714 : }
1715 :
1716 0 : mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1717 : I_MUTEX_PARENT);
1718 0 : mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
1719 0 : mutex_lock(&configfs_symlink_mutex);
1720 0 : spin_lock(&configfs_dirent_lock);
1721 0 : if (configfs_detach_prep(dentry, NULL)) {
1722 0 : printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
1723 : }
1724 0 : spin_unlock(&configfs_dirent_lock);
1725 0 : mutex_unlock(&configfs_symlink_mutex);
1726 0 : configfs_detach_group(&group->cg_item);
1727 0 : dentry->d_inode->i_flags |= S_DEAD;
1728 0 : mutex_unlock(&dentry->d_inode->i_mutex);
1729 :
1730 0 : d_delete(dentry);
1731 :
1732 0 : mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1733 :
1734 0 : dput(dentry);
1735 :
1736 0 : unlink_group(group);
1737 0 : configfs_release_fs();
1738 0 : }
1739 :
1740 : EXPORT_SYMBOL(configfs_register_subsystem);
1741 : EXPORT_SYMBOL(configfs_unregister_subsystem);
|