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 34 #include <linux/configfs.h> 35 #include "configfs_internal.h" 36 37 DECLARE_RWSEM(configfs_rename_sem); 38 39 static void configfs_d_iput(struct dentry * dentry, 40 struct inode * inode) 41 { 42 struct configfs_dirent * sd = dentry->d_fsdata; 43 44 if (sd) { 45 BUG_ON(sd->s_dentry != dentry); 46 sd->s_dentry = NULL; 47 configfs_put(sd); 48 } 49 iput(inode); 50 } 51 52 /* 53 * We _must_ delete our dentries on last dput, as the chain-to-parent 54 * behavior is required to clear the parents of default_groups. 55 */ 56 static int configfs_d_delete(struct dentry *dentry) 57 { 58 return 1; 59 } 60 61 static struct dentry_operations configfs_dentry_ops = { 62 .d_iput = configfs_d_iput, 63 /* simple_delete_dentry() isn't exported */ 64 .d_delete = configfs_d_delete, 65 }; 66 67 /* 68 * Allocates a new configfs_dirent and links it to the parent configfs_dirent 69 */ 70 static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * parent_sd, 71 void * element) 72 { 73 struct configfs_dirent * sd; 74 75 sd = kmem_cache_alloc(configfs_dir_cachep, GFP_KERNEL); 76 if (!sd) 77 return NULL; 78 79 memset(sd, 0, sizeof(*sd)); 80 atomic_set(&sd->s_count, 1); 81 INIT_LIST_HEAD(&sd->s_links); 82 INIT_LIST_HEAD(&sd->s_children); 83 list_add(&sd->s_sibling, &parent_sd->s_children); 84 sd->s_element = element; 85 86 return sd; 87 } 88 89 int configfs_make_dirent(struct configfs_dirent * parent_sd, 90 struct dentry * dentry, void * element, 91 umode_t mode, int type) 92 { 93 struct configfs_dirent * sd; 94 95 sd = configfs_new_dirent(parent_sd, element); 96 if (!sd) 97 return -ENOMEM; 98 99 sd->s_mode = mode; 100 sd->s_type = type; 101 sd->s_dentry = dentry; 102 if (dentry) { 103 dentry->d_fsdata = configfs_get(sd); 104 dentry->d_op = &configfs_dentry_ops; 105 } 106 107 return 0; 108 } 109 110 static int init_dir(struct inode * inode) 111 { 112 inode->i_op = &configfs_dir_inode_operations; 113 inode->i_fop = &configfs_dir_operations; 114 115 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 116 inode->i_nlink++; 117 return 0; 118 } 119 120 static int init_file(struct inode * inode) 121 { 122 inode->i_size = PAGE_SIZE; 123 inode->i_fop = &configfs_file_operations; 124 return 0; 125 } 126 127 static int init_symlink(struct inode * inode) 128 { 129 inode->i_op = &configfs_symlink_inode_operations; 130 return 0; 131 } 132 133 static int create_dir(struct config_item * k, struct dentry * p, 134 struct dentry * d) 135 { 136 int error; 137 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; 138 139 error = configfs_make_dirent(p->d_fsdata, d, k, mode, 140 CONFIGFS_DIR); 141 if (!error) { 142 error = configfs_create(d, mode, init_dir); 143 if (!error) { 144 p->d_inode->i_nlink++; 145 (d)->d_op = &configfs_dentry_ops; 146 } else { 147 struct configfs_dirent *sd = d->d_fsdata; 148 if (sd) { 149 list_del_init(&sd->s_sibling); 150 configfs_put(sd); 151 } 152 } 153 } 154 return error; 155 } 156 157 158 /** 159 * configfs_create_dir - create a directory for an config_item. 160 * @item: config_itemwe're creating directory for. 161 * @dentry: config_item's dentry. 162 */ 163 164 static int configfs_create_dir(struct config_item * item, struct dentry *dentry) 165 { 166 struct dentry * parent; 167 int error = 0; 168 169 BUG_ON(!item); 170 171 if (item->ci_parent) 172 parent = item->ci_parent->ci_dentry; 173 else if (configfs_mount && configfs_mount->mnt_sb) 174 parent = configfs_mount->mnt_sb->s_root; 175 else 176 return -EFAULT; 177 178 error = create_dir(item,parent,dentry); 179 if (!error) 180 item->ci_dentry = dentry; 181 return error; 182 } 183 184 int configfs_create_link(struct configfs_symlink *sl, 185 struct dentry *parent, 186 struct dentry *dentry) 187 { 188 int err = 0; 189 umode_t mode = S_IFLNK | S_IRWXUGO; 190 191 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, 192 CONFIGFS_ITEM_LINK); 193 if (!err) { 194 err = configfs_create(dentry, mode, init_symlink); 195 if (!err) 196 dentry->d_op = &configfs_dentry_ops; 197 else { 198 struct configfs_dirent *sd = dentry->d_fsdata; 199 if (sd) { 200 list_del_init(&sd->s_sibling); 201 configfs_put(sd); 202 } 203 } 204 } 205 return err; 206 } 207 208 static void remove_dir(struct dentry * d) 209 { 210 struct dentry * parent = dget(d->d_parent); 211 struct configfs_dirent * sd; 212 213 sd = d->d_fsdata; 214 list_del_init(&sd->s_sibling); 215 configfs_put(sd); 216 if (d->d_inode) 217 simple_rmdir(parent->d_inode,d); 218 219 pr_debug(" o %s removing done (%d)\n",d->d_name.name, 220 atomic_read(&d->d_count)); 221 222 dput(parent); 223 } 224 225 /** 226 * configfs_remove_dir - remove an config_item's directory. 227 * @item: config_item we're removing. 228 * 229 * The only thing special about this is that we remove any files in 230 * the directory before we remove the directory, and we've inlined 231 * what used to be configfs_rmdir() below, instead of calling separately. 232 */ 233 234 static void configfs_remove_dir(struct config_item * item) 235 { 236 struct dentry * dentry = dget(item->ci_dentry); 237 238 if (!dentry) 239 return; 240 241 remove_dir(dentry); 242 /** 243 * Drop reference from dget() on entrance. 244 */ 245 dput(dentry); 246 } 247 248 249 /* attaches attribute's configfs_dirent to the dentry corresponding to the 250 * attribute file 251 */ 252 static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) 253 { 254 struct configfs_attribute * attr = sd->s_element; 255 int error; 256 257 dentry->d_fsdata = configfs_get(sd); 258 sd->s_dentry = dentry; 259 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file); 260 if (error) { 261 configfs_put(sd); 262 return error; 263 } 264 265 dentry->d_op = &configfs_dentry_ops; 266 d_rehash(dentry); 267 268 return 0; 269 } 270 271 static struct dentry * configfs_lookup(struct inode *dir, 272 struct dentry *dentry, 273 struct nameidata *nd) 274 { 275 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; 276 struct configfs_dirent * sd; 277 int found = 0; 278 int err = 0; 279 280 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { 281 if (sd->s_type & CONFIGFS_NOT_PINNED) { 282 const unsigned char * name = configfs_get_name(sd); 283 284 if (strcmp(name, dentry->d_name.name)) 285 continue; 286 287 found = 1; 288 err = configfs_attach_attr(sd, dentry); 289 break; 290 } 291 } 292 293 if (!found) { 294 /* 295 * If it doesn't exist and it isn't a NOT_PINNED item, 296 * it must be negative. 297 */ 298 return simple_lookup(dir, dentry, nd); 299 } 300 301 return ERR_PTR(err); 302 } 303 304 /* 305 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are 306 * attributes and are removed by rmdir(). We recurse, taking i_mutex 307 * on all children that are candidates for default detach. If the 308 * result is clean, then configfs_detach_group() will handle dropping 309 * i_mutex. If there is an error, the caller will clean up the i_mutex 310 * holders via configfs_detach_rollback(). 311 */ 312 static int configfs_detach_prep(struct dentry *dentry) 313 { 314 struct configfs_dirent *parent_sd = dentry->d_fsdata; 315 struct configfs_dirent *sd; 316 int ret; 317 318 ret = -EBUSY; 319 if (!list_empty(&parent_sd->s_links)) 320 goto out; 321 322 ret = 0; 323 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { 324 if (sd->s_type & CONFIGFS_NOT_PINNED) 325 continue; 326 if (sd->s_type & CONFIGFS_USET_DEFAULT) { 327 mutex_lock(&sd->s_dentry->d_inode->i_mutex); 328 /* Mark that we've taken i_mutex */ 329 sd->s_type |= CONFIGFS_USET_DROPPING; 330 331 ret = configfs_detach_prep(sd->s_dentry); 332 if (!ret) 333 continue; 334 } else 335 ret = -ENOTEMPTY; 336 337 break; 338 } 339 340 out: 341 return ret; 342 } 343 344 /* 345 * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is 346 * set. 347 */ 348 static void configfs_detach_rollback(struct dentry *dentry) 349 { 350 struct configfs_dirent *parent_sd = dentry->d_fsdata; 351 struct configfs_dirent *sd; 352 353 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { 354 if (sd->s_type & CONFIGFS_USET_DEFAULT) { 355 configfs_detach_rollback(sd->s_dentry); 356 357 if (sd->s_type & CONFIGFS_USET_DROPPING) { 358 sd->s_type &= ~CONFIGFS_USET_DROPPING; 359 mutex_unlock(&sd->s_dentry->d_inode->i_mutex); 360 } 361 } 362 } 363 } 364 365 static void detach_attrs(struct config_item * item) 366 { 367 struct dentry * dentry = dget(item->ci_dentry); 368 struct configfs_dirent * parent_sd; 369 struct configfs_dirent * sd, * tmp; 370 371 if (!dentry) 372 return; 373 374 pr_debug("configfs %s: dropping attrs for dir\n", 375 dentry->d_name.name); 376 377 parent_sd = dentry->d_fsdata; 378 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { 379 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) 380 continue; 381 list_del_init(&sd->s_sibling); 382 configfs_drop_dentry(sd, dentry); 383 configfs_put(sd); 384 } 385 386 /** 387 * Drop reference from dget() on entrance. 388 */ 389 dput(dentry); 390 } 391 392 static int populate_attrs(struct config_item *item) 393 { 394 struct config_item_type *t = item->ci_type; 395 struct configfs_attribute *attr; 396 int error = 0; 397 int i; 398 399 if (!t) 400 return -EINVAL; 401 if (t->ct_attrs) { 402 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { 403 if ((error = configfs_create_file(item, attr))) 404 break; 405 } 406 } 407 408 if (error) 409 detach_attrs(item); 410 411 return error; 412 } 413 414 static int configfs_attach_group(struct config_item *parent_item, 415 struct config_item *item, 416 struct dentry *dentry); 417 static void configfs_detach_group(struct config_item *item); 418 419 static void detach_groups(struct config_group *group) 420 { 421 struct dentry * dentry = dget(group->cg_item.ci_dentry); 422 struct dentry *child; 423 struct configfs_dirent *parent_sd; 424 struct configfs_dirent *sd, *tmp; 425 426 if (!dentry) 427 return; 428 429 parent_sd = dentry->d_fsdata; 430 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { 431 if (!sd->s_element || 432 !(sd->s_type & CONFIGFS_USET_DEFAULT)) 433 continue; 434 435 child = sd->s_dentry; 436 437 configfs_detach_group(sd->s_element); 438 child->d_inode->i_flags |= S_DEAD; 439 440 /* 441 * From rmdir/unregister, a configfs_detach_prep() pass 442 * has taken our i_mutex for us. Drop it. 443 * From mkdir/register cleanup, there is no sem held. 444 */ 445 if (sd->s_type & CONFIGFS_USET_DROPPING) 446 mutex_unlock(&child->d_inode->i_mutex); 447 448 d_delete(child); 449 dput(child); 450 } 451 452 /** 453 * Drop reference from dget() on entrance. 454 */ 455 dput(dentry); 456 } 457 458 /* 459 * This fakes mkdir(2) on a default_groups[] entry. It 460 * creates a dentry, attachs it, and then does fixup 461 * on the sd->s_type. 462 * 463 * We could, perhaps, tweak our parent's ->mkdir for a minute and 464 * try using vfs_mkdir. Just a thought. 465 */ 466 static int create_default_group(struct config_group *parent_group, 467 struct config_group *group) 468 { 469 int ret; 470 struct qstr name; 471 struct configfs_dirent *sd; 472 /* We trust the caller holds a reference to parent */ 473 struct dentry *child, *parent = parent_group->cg_item.ci_dentry; 474 475 if (!group->cg_item.ci_name) 476 group->cg_item.ci_name = group->cg_item.ci_namebuf; 477 name.name = group->cg_item.ci_name; 478 name.len = strlen(name.name); 479 name.hash = full_name_hash(name.name, name.len); 480 481 ret = -ENOMEM; 482 child = d_alloc(parent, &name); 483 if (child) { 484 d_add(child, NULL); 485 486 ret = configfs_attach_group(&parent_group->cg_item, 487 &group->cg_item, child); 488 if (!ret) { 489 sd = child->d_fsdata; 490 sd->s_type |= CONFIGFS_USET_DEFAULT; 491 } else { 492 d_delete(child); 493 dput(child); 494 } 495 } 496 497 return ret; 498 } 499 500 static int populate_groups(struct config_group *group) 501 { 502 struct config_group *new_group; 503 struct dentry *dentry = group->cg_item.ci_dentry; 504 int ret = 0; 505 int i; 506 507 if (group->default_groups) { 508 /* 509 * FYI, we're faking mkdir here 510 * I'm not sure we need this semaphore, as we're called 511 * from our parent's mkdir. That holds our parent's 512 * i_mutex, so afaik lookup cannot continue through our 513 * parent to find us, let alone mess with our tree. 514 * That said, taking our i_mutex is closer to mkdir 515 * emulation, and shouldn't hurt. 516 */ 517 mutex_lock(&dentry->d_inode->i_mutex); 518 519 for (i = 0; group->default_groups[i]; i++) { 520 new_group = group->default_groups[i]; 521 522 ret = create_default_group(group, new_group); 523 if (ret) 524 break; 525 } 526 527 mutex_unlock(&dentry->d_inode->i_mutex); 528 } 529 530 if (ret) 531 detach_groups(group); 532 533 return ret; 534 } 535 536 /* 537 * All of link_obj/unlink_obj/link_group/unlink_group require that 538 * subsys->su_sem is held. 539 */ 540 541 static void unlink_obj(struct config_item *item) 542 { 543 struct config_group *group; 544 545 group = item->ci_group; 546 if (group) { 547 list_del_init(&item->ci_entry); 548 549 item->ci_group = NULL; 550 item->ci_parent = NULL; 551 552 /* Drop the reference for ci_entry */ 553 config_item_put(item); 554 555 /* Drop the reference for ci_parent */ 556 config_group_put(group); 557 } 558 } 559 560 static void link_obj(struct config_item *parent_item, struct config_item *item) 561 { 562 /* 563 * Parent seems redundant with group, but it makes certain 564 * traversals much nicer. 565 */ 566 item->ci_parent = parent_item; 567 568 /* 569 * We hold a reference on the parent for the child's ci_parent 570 * link. 571 */ 572 item->ci_group = config_group_get(to_config_group(parent_item)); 573 list_add_tail(&item->ci_entry, &item->ci_group->cg_children); 574 575 /* 576 * We hold a reference on the child for ci_entry on the parent's 577 * cg_children 578 */ 579 config_item_get(item); 580 } 581 582 static void unlink_group(struct config_group *group) 583 { 584 int i; 585 struct config_group *new_group; 586 587 if (group->default_groups) { 588 for (i = 0; group->default_groups[i]; i++) { 589 new_group = group->default_groups[i]; 590 unlink_group(new_group); 591 } 592 } 593 594 group->cg_subsys = NULL; 595 unlink_obj(&group->cg_item); 596 } 597 598 static void link_group(struct config_group *parent_group, struct config_group *group) 599 { 600 int i; 601 struct config_group *new_group; 602 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ 603 604 link_obj(&parent_group->cg_item, &group->cg_item); 605 606 if (parent_group->cg_subsys) 607 subsys = parent_group->cg_subsys; 608 else if (configfs_is_root(&parent_group->cg_item)) 609 subsys = to_configfs_subsystem(group); 610 else 611 BUG(); 612 group->cg_subsys = subsys; 613 614 if (group->default_groups) { 615 for (i = 0; group->default_groups[i]; i++) { 616 new_group = group->default_groups[i]; 617 link_group(group, new_group); 618 } 619 } 620 } 621 622 /* 623 * The goal is that configfs_attach_item() (and 624 * configfs_attach_group()) can be called from either the VFS or this 625 * module. That is, they assume that the items have been created, 626 * the dentry allocated, and the dcache is all ready to go. 627 * 628 * If they fail, they must clean up after themselves as if they 629 * had never been called. The caller (VFS or local function) will 630 * handle cleaning up the dcache bits. 631 * 632 * configfs_detach_group() and configfs_detach_item() behave similarly on 633 * the way out. They assume that the proper semaphores are held, they 634 * clean up the configfs items, and they expect their callers will 635 * handle the dcache bits. 636 */ 637 static int configfs_attach_item(struct config_item *parent_item, 638 struct config_item *item, 639 struct dentry *dentry) 640 { 641 int ret; 642 643 ret = configfs_create_dir(item, dentry); 644 if (!ret) { 645 ret = populate_attrs(item); 646 if (ret) { 647 configfs_remove_dir(item); 648 d_delete(dentry); 649 } 650 } 651 652 return ret; 653 } 654 655 static void configfs_detach_item(struct config_item *item) 656 { 657 detach_attrs(item); 658 configfs_remove_dir(item); 659 } 660 661 static int configfs_attach_group(struct config_item *parent_item, 662 struct config_item *item, 663 struct dentry *dentry) 664 { 665 int ret; 666 struct configfs_dirent *sd; 667 668 ret = configfs_attach_item(parent_item, item, dentry); 669 if (!ret) { 670 sd = dentry->d_fsdata; 671 sd->s_type |= CONFIGFS_USET_DIR; 672 673 ret = populate_groups(to_config_group(item)); 674 if (ret) { 675 configfs_detach_item(item); 676 d_delete(dentry); 677 } 678 } 679 680 return ret; 681 } 682 683 static void configfs_detach_group(struct config_item *item) 684 { 685 detach_groups(to_config_group(item)); 686 configfs_detach_item(item); 687 } 688 689 /* 690 * Drop the initial reference from make_item()/make_group() 691 * This function assumes that reference is held on item 692 * and that item holds a valid reference to the parent. Also, it 693 * assumes the caller has validated ci_type. 694 */ 695 static void client_drop_item(struct config_item *parent_item, 696 struct config_item *item) 697 { 698 struct config_item_type *type; 699 700 type = parent_item->ci_type; 701 BUG_ON(!type); 702 703 /* 704 * If ->drop_item() exists, it is responsible for the 705 * config_item_put(). 706 */ 707 if (type->ct_group_ops && type->ct_group_ops->drop_item) 708 type->ct_group_ops->drop_item(to_config_group(parent_item), 709 item); 710 else 711 config_item_put(item); 712 } 713 714 715 static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 716 { 717 int ret, module_got = 0; 718 struct config_group *group; 719 struct config_item *item; 720 struct config_item *parent_item; 721 struct configfs_subsystem *subsys; 722 struct configfs_dirent *sd; 723 struct config_item_type *type; 724 struct module *owner = NULL; 725 char *name; 726 727 if (dentry->d_parent == configfs_sb->s_root) { 728 ret = -EPERM; 729 goto out; 730 } 731 732 sd = dentry->d_parent->d_fsdata; 733 if (!(sd->s_type & CONFIGFS_USET_DIR)) { 734 ret = -EPERM; 735 goto out; 736 } 737 738 /* Get a working ref for the duration of this function */ 739 parent_item = configfs_get_config_item(dentry->d_parent); 740 type = parent_item->ci_type; 741 subsys = to_config_group(parent_item)->cg_subsys; 742 BUG_ON(!subsys); 743 744 if (!type || !type->ct_group_ops || 745 (!type->ct_group_ops->make_group && 746 !type->ct_group_ops->make_item)) { 747 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ 748 goto out_put; 749 } 750 751 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); 752 if (!name) { 753 ret = -ENOMEM; 754 goto out_put; 755 } 756 757 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); 758 759 down(&subsys->su_sem); 760 group = NULL; 761 item = NULL; 762 if (type->ct_group_ops->make_group) { 763 group = type->ct_group_ops->make_group(to_config_group(parent_item), name); 764 if (group) { 765 link_group(to_config_group(parent_item), group); 766 item = &group->cg_item; 767 } 768 } else { 769 item = type->ct_group_ops->make_item(to_config_group(parent_item), name); 770 if (item) 771 link_obj(parent_item, item); 772 } 773 up(&subsys->su_sem); 774 775 kfree(name); 776 if (!item) { 777 /* 778 * If item == NULL, then link_obj() was never called. 779 * There are no extra references to clean up. 780 */ 781 ret = -ENOMEM; 782 goto out_put; 783 } 784 785 /* 786 * link_obj() has been called (via link_group() for groups). 787 * From here on out, errors must clean that up. 788 */ 789 790 type = item->ci_type; 791 if (!type) { 792 ret = -EINVAL; 793 goto out_unlink; 794 } 795 796 owner = type->ct_owner; 797 if (!try_module_get(owner)) { 798 ret = -EINVAL; 799 goto out_unlink; 800 } 801 802 /* 803 * I hate doing it this way, but if there is 804 * an error, module_put() probably should 805 * happen after any cleanup. 806 */ 807 module_got = 1; 808 809 if (group) 810 ret = configfs_attach_group(parent_item, item, dentry); 811 else 812 ret = configfs_attach_item(parent_item, item, dentry); 813 814 out_unlink: 815 if (ret) { 816 /* Tear down everything we built up */ 817 down(&subsys->su_sem); 818 if (group) 819 unlink_group(group); 820 else 821 unlink_obj(item); 822 client_drop_item(parent_item, item); 823 up(&subsys->su_sem); 824 825 if (module_got) 826 module_put(owner); 827 } 828 829 out_put: 830 /* 831 * link_obj()/link_group() took a reference from child->parent, 832 * so the parent is safely pinned. We can drop our working 833 * reference. 834 */ 835 config_item_put(parent_item); 836 837 out: 838 return ret; 839 } 840 841 static int configfs_rmdir(struct inode *dir, struct dentry *dentry) 842 { 843 struct config_item *parent_item; 844 struct config_item *item; 845 struct configfs_subsystem *subsys; 846 struct configfs_dirent *sd; 847 struct module *owner = NULL; 848 int ret; 849 850 if (dentry->d_parent == configfs_sb->s_root) 851 return -EPERM; 852 853 sd = dentry->d_fsdata; 854 if (sd->s_type & CONFIGFS_USET_DEFAULT) 855 return -EPERM; 856 857 /* Get a working ref until we have the child */ 858 parent_item = configfs_get_config_item(dentry->d_parent); 859 subsys = to_config_group(parent_item)->cg_subsys; 860 BUG_ON(!subsys); 861 862 if (!parent_item->ci_type) { 863 config_item_put(parent_item); 864 return -EINVAL; 865 } 866 867 ret = configfs_detach_prep(dentry); 868 if (ret) { 869 configfs_detach_rollback(dentry); 870 config_item_put(parent_item); 871 return ret; 872 } 873 874 /* Get a working ref for the duration of this function */ 875 item = configfs_get_config_item(dentry); 876 877 /* Drop reference from above, item already holds one. */ 878 config_item_put(parent_item); 879 880 if (item->ci_type) 881 owner = item->ci_type->ct_owner; 882 883 if (sd->s_type & CONFIGFS_USET_DIR) { 884 configfs_detach_group(item); 885 886 down(&subsys->su_sem); 887 unlink_group(to_config_group(item)); 888 } else { 889 configfs_detach_item(item); 890 891 down(&subsys->su_sem); 892 unlink_obj(item); 893 } 894 895 client_drop_item(parent_item, item); 896 up(&subsys->su_sem); 897 898 /* Drop our reference from above */ 899 config_item_put(item); 900 901 module_put(owner); 902 903 return 0; 904 } 905 906 struct inode_operations configfs_dir_inode_operations = { 907 .mkdir = configfs_mkdir, 908 .rmdir = configfs_rmdir, 909 .symlink = configfs_symlink, 910 .unlink = configfs_unlink, 911 .lookup = configfs_lookup, 912 .setattr = configfs_setattr, 913 }; 914 915 #if 0 916 int configfs_rename_dir(struct config_item * item, const char *new_name) 917 { 918 int error = 0; 919 struct dentry * new_dentry, * parent; 920 921 if (!strcmp(config_item_name(item), new_name)) 922 return -EINVAL; 923 924 if (!item->parent) 925 return -EINVAL; 926 927 down_write(&configfs_rename_sem); 928 parent = item->parent->dentry; 929 930 mutex_lock(&parent->d_inode->i_mutex); 931 932 new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); 933 if (!IS_ERR(new_dentry)) { 934 if (!new_dentry->d_inode) { 935 error = config_item_set_name(item, "%s", new_name); 936 if (!error) { 937 d_add(new_dentry, NULL); 938 d_move(item->dentry, new_dentry); 939 } 940 else 941 d_delete(new_dentry); 942 } else 943 error = -EEXIST; 944 dput(new_dentry); 945 } 946 mutex_unlock(&parent->d_inode->i_mutex); 947 up_write(&configfs_rename_sem); 948 949 return error; 950 } 951 #endif 952 953 static int configfs_dir_open(struct inode *inode, struct file *file) 954 { 955 struct dentry * dentry = file->f_dentry; 956 struct configfs_dirent * parent_sd = dentry->d_fsdata; 957 958 mutex_lock(&dentry->d_inode->i_mutex); 959 file->private_data = configfs_new_dirent(parent_sd, NULL); 960 mutex_unlock(&dentry->d_inode->i_mutex); 961 962 return file->private_data ? 0 : -ENOMEM; 963 964 } 965 966 static int configfs_dir_close(struct inode *inode, struct file *file) 967 { 968 struct dentry * dentry = file->f_dentry; 969 struct configfs_dirent * cursor = file->private_data; 970 971 mutex_lock(&dentry->d_inode->i_mutex); 972 list_del_init(&cursor->s_sibling); 973 mutex_unlock(&dentry->d_inode->i_mutex); 974 975 release_configfs_dirent(cursor); 976 977 return 0; 978 } 979 980 /* Relationship between s_mode and the DT_xxx types */ 981 static inline unsigned char dt_type(struct configfs_dirent *sd) 982 { 983 return (sd->s_mode >> 12) & 15; 984 } 985 986 static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) 987 { 988 struct dentry *dentry = filp->f_dentry; 989 struct configfs_dirent * parent_sd = dentry->d_fsdata; 990 struct configfs_dirent *cursor = filp->private_data; 991 struct list_head *p, *q = &cursor->s_sibling; 992 ino_t ino; 993 int i = filp->f_pos; 994 995 switch (i) { 996 case 0: 997 ino = dentry->d_inode->i_ino; 998 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) 999 break; 1000 filp->f_pos++; 1001 i++; 1002 /* fallthrough */ 1003 case 1: 1004 ino = parent_ino(dentry); 1005 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) 1006 break; 1007 filp->f_pos++; 1008 i++; 1009 /* fallthrough */ 1010 default: 1011 if (filp->f_pos == 2) { 1012 list_move(q, &parent_sd->s_children); 1013 } 1014 for (p=q->next; p!= &parent_sd->s_children; p=p->next) { 1015 struct configfs_dirent *next; 1016 const char * name; 1017 int len; 1018 1019 next = list_entry(p, struct configfs_dirent, 1020 s_sibling); 1021 if (!next->s_element) 1022 continue; 1023 1024 name = configfs_get_name(next); 1025 len = strlen(name); 1026 if (next->s_dentry) 1027 ino = next->s_dentry->d_inode->i_ino; 1028 else 1029 ino = iunique(configfs_sb, 2); 1030 1031 if (filldir(dirent, name, len, filp->f_pos, ino, 1032 dt_type(next)) < 0) 1033 return 0; 1034 1035 list_move(q, p); 1036 p = q; 1037 filp->f_pos++; 1038 } 1039 } 1040 return 0; 1041 } 1042 1043 static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin) 1044 { 1045 struct dentry * dentry = file->f_dentry; 1046 1047 mutex_lock(&dentry->d_inode->i_mutex); 1048 switch (origin) { 1049 case 1: 1050 offset += file->f_pos; 1051 case 0: 1052 if (offset >= 0) 1053 break; 1054 default: 1055 mutex_unlock(&file->f_dentry->d_inode->i_mutex); 1056 return -EINVAL; 1057 } 1058 if (offset != file->f_pos) { 1059 file->f_pos = offset; 1060 if (file->f_pos >= 2) { 1061 struct configfs_dirent *sd = dentry->d_fsdata; 1062 struct configfs_dirent *cursor = file->private_data; 1063 struct list_head *p; 1064 loff_t n = file->f_pos - 2; 1065 1066 list_del(&cursor->s_sibling); 1067 p = sd->s_children.next; 1068 while (n && p != &sd->s_children) { 1069 struct configfs_dirent *next; 1070 next = list_entry(p, struct configfs_dirent, 1071 s_sibling); 1072 if (next->s_element) 1073 n--; 1074 p = p->next; 1075 } 1076 list_add_tail(&cursor->s_sibling, p); 1077 } 1078 } 1079 mutex_unlock(&dentry->d_inode->i_mutex); 1080 return offset; 1081 } 1082 1083 const struct file_operations configfs_dir_operations = { 1084 .open = configfs_dir_open, 1085 .release = configfs_dir_close, 1086 .llseek = configfs_dir_lseek, 1087 .read = generic_read_dir, 1088 .readdir = configfs_readdir, 1089 }; 1090 1091 int configfs_register_subsystem(struct configfs_subsystem *subsys) 1092 { 1093 int err; 1094 struct config_group *group = &subsys->su_group; 1095 struct qstr name; 1096 struct dentry *dentry; 1097 struct configfs_dirent *sd; 1098 1099 err = configfs_pin_fs(); 1100 if (err) 1101 return err; 1102 1103 if (!group->cg_item.ci_name) 1104 group->cg_item.ci_name = group->cg_item.ci_namebuf; 1105 1106 sd = configfs_sb->s_root->d_fsdata; 1107 link_group(to_config_group(sd->s_element), group); 1108 1109 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex); 1110 1111 name.name = group->cg_item.ci_name; 1112 name.len = strlen(name.name); 1113 name.hash = full_name_hash(name.name, name.len); 1114 1115 err = -ENOMEM; 1116 dentry = d_alloc(configfs_sb->s_root, &name); 1117 if (!dentry) 1118 goto out_release; 1119 1120 d_add(dentry, NULL); 1121 1122 err = configfs_attach_group(sd->s_element, &group->cg_item, 1123 dentry); 1124 if (!err) 1125 dentry = NULL; 1126 else 1127 d_delete(dentry); 1128 1129 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); 1130 1131 if (dentry) { 1132 dput(dentry); 1133 out_release: 1134 unlink_group(group); 1135 configfs_release_fs(); 1136 } 1137 1138 return err; 1139 } 1140 1141 void configfs_unregister_subsystem(struct configfs_subsystem *subsys) 1142 { 1143 struct config_group *group = &subsys->su_group; 1144 struct dentry *dentry = group->cg_item.ci_dentry; 1145 1146 if (dentry->d_parent != configfs_sb->s_root) { 1147 printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); 1148 return; 1149 } 1150 1151 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex); 1152 mutex_lock(&dentry->d_inode->i_mutex); 1153 if (configfs_detach_prep(dentry)) { 1154 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); 1155 } 1156 configfs_detach_group(&group->cg_item); 1157 dentry->d_inode->i_flags |= S_DEAD; 1158 mutex_unlock(&dentry->d_inode->i_mutex); 1159 1160 d_delete(dentry); 1161 1162 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); 1163 1164 dput(dentry); 1165 1166 unlink_group(group); 1167 configfs_release_fs(); 1168 } 1169 1170 EXPORT_SYMBOL(configfs_register_subsystem); 1171 EXPORT_SYMBOL(configfs_unregister_subsystem); 1172