1 /* CacheFiles path walking and related routines 2 * 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public Licence 8 * as published by the Free Software Foundation; either version 9 * 2 of the Licence, or (at your option) any later version. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/sched.h> 14 #include <linux/file.h> 15 #include <linux/fs.h> 16 #include <linux/fsnotify.h> 17 #include <linux/quotaops.h> 18 #include <linux/xattr.h> 19 #include <linux/mount.h> 20 #include <linux/namei.h> 21 #include <linux/security.h> 22 #include <linux/slab.h> 23 #include <linux/xattr.h> 24 #include "internal.h" 25 26 #define CACHEFILES_KEYBUF_SIZE 512 27 28 /* 29 * dump debugging info about an object 30 */ 31 static noinline 32 void __cachefiles_printk_object(struct cachefiles_object *object, 33 const char *prefix) 34 { 35 struct fscache_cookie *cookie; 36 const u8 *k; 37 unsigned loop; 38 39 pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id); 40 pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n", 41 prefix, object->fscache.state->name, 42 object->fscache.flags, work_busy(&object->fscache.work), 43 object->fscache.events, object->fscache.event_mask); 44 pr_err("%sops=%u inp=%u exc=%u\n", 45 prefix, object->fscache.n_ops, object->fscache.n_in_progress, 46 object->fscache.n_exclusive); 47 pr_err("%sparent=%p\n", 48 prefix, object->fscache.parent); 49 50 spin_lock(&object->fscache.lock); 51 cookie = object->fscache.cookie; 52 if (cookie) { 53 pr_err("%scookie=%p [pr=%p nd=%p fl=%lx]\n", 54 prefix, 55 object->fscache.cookie, 56 object->fscache.cookie->parent, 57 object->fscache.cookie->netfs_data, 58 object->fscache.cookie->flags); 59 pr_err("%skey=[%u] '", prefix, cookie->key_len); 60 k = (cookie->key_len <= sizeof(cookie->inline_key)) ? 61 cookie->inline_key : cookie->key; 62 for (loop = 0; loop < cookie->key_len; loop++) 63 pr_cont("%02x", k[loop]); 64 pr_cont("'\n"); 65 } else { 66 pr_err("%scookie=NULL\n", prefix); 67 } 68 spin_unlock(&object->fscache.lock); 69 } 70 71 /* 72 * dump debugging info about a pair of objects 73 */ 74 static noinline void cachefiles_printk_object(struct cachefiles_object *object, 75 struct cachefiles_object *xobject) 76 { 77 if (object) 78 __cachefiles_printk_object(object, ""); 79 if (xobject) 80 __cachefiles_printk_object(xobject, "x"); 81 } 82 83 /* 84 * mark the owner of a dentry, if there is one, to indicate that that dentry 85 * has been preemptively deleted 86 * - the caller must hold the i_mutex on the dentry's parent as required to 87 * call vfs_unlink(), vfs_rmdir() or vfs_rename() 88 */ 89 static void cachefiles_mark_object_buried(struct cachefiles_cache *cache, 90 struct dentry *dentry, 91 enum fscache_why_object_killed why) 92 { 93 struct cachefiles_object *object; 94 struct rb_node *p; 95 96 _enter(",'%pd'", dentry); 97 98 write_lock(&cache->active_lock); 99 100 p = cache->active_nodes.rb_node; 101 while (p) { 102 object = rb_entry(p, struct cachefiles_object, active_node); 103 if (object->dentry > dentry) 104 p = p->rb_left; 105 else if (object->dentry < dentry) 106 p = p->rb_right; 107 else 108 goto found_dentry; 109 } 110 111 write_unlock(&cache->active_lock); 112 trace_cachefiles_mark_buried(NULL, dentry, why); 113 _leave(" [no owner]"); 114 return; 115 116 /* found the dentry for */ 117 found_dentry: 118 kdebug("preemptive burial: OBJ%x [%s] %p", 119 object->fscache.debug_id, 120 object->fscache.state->name, 121 dentry); 122 123 trace_cachefiles_mark_buried(object, dentry, why); 124 125 if (fscache_object_is_live(&object->fscache)) { 126 pr_err("\n"); 127 pr_err("Error: Can't preemptively bury live object\n"); 128 cachefiles_printk_object(object, NULL); 129 } else { 130 if (why != FSCACHE_OBJECT_IS_STALE) 131 fscache_object_mark_killed(&object->fscache, why); 132 } 133 134 write_unlock(&cache->active_lock); 135 _leave(" [owner marked]"); 136 } 137 138 /* 139 * record the fact that an object is now active 140 */ 141 static int cachefiles_mark_object_active(struct cachefiles_cache *cache, 142 struct cachefiles_object *object) 143 { 144 struct cachefiles_object *xobject; 145 struct rb_node **_p, *_parent = NULL; 146 struct dentry *dentry; 147 148 _enter(",%p", object); 149 150 try_again: 151 write_lock(&cache->active_lock); 152 153 dentry = object->dentry; 154 trace_cachefiles_mark_active(object, dentry); 155 156 if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { 157 pr_err("Error: Object already active\n"); 158 cachefiles_printk_object(object, NULL); 159 BUG(); 160 } 161 162 _p = &cache->active_nodes.rb_node; 163 while (*_p) { 164 _parent = *_p; 165 xobject = rb_entry(_parent, 166 struct cachefiles_object, active_node); 167 168 ASSERT(xobject != object); 169 170 if (xobject->dentry > dentry) 171 _p = &(*_p)->rb_left; 172 else if (xobject->dentry < dentry) 173 _p = &(*_p)->rb_right; 174 else 175 goto wait_for_old_object; 176 } 177 178 rb_link_node(&object->active_node, _parent, _p); 179 rb_insert_color(&object->active_node, &cache->active_nodes); 180 181 write_unlock(&cache->active_lock); 182 _leave(" = 0"); 183 return 0; 184 185 /* an old object from a previous incarnation is hogging the slot - we 186 * need to wait for it to be destroyed */ 187 wait_for_old_object: 188 trace_cachefiles_wait_active(object, dentry, xobject); 189 190 if (fscache_object_is_live(&xobject->fscache)) { 191 pr_err("\n"); 192 pr_err("Error: Unexpected object collision\n"); 193 cachefiles_printk_object(object, xobject); 194 BUG(); 195 } 196 atomic_inc(&xobject->usage); 197 write_unlock(&cache->active_lock); 198 199 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { 200 wait_queue_head_t *wq; 201 202 signed long timeout = 60 * HZ; 203 wait_queue_entry_t wait; 204 bool requeue; 205 206 /* if the object we're waiting for is queued for processing, 207 * then just put ourselves on the queue behind it */ 208 if (work_pending(&xobject->fscache.work)) { 209 _debug("queue OBJ%x behind OBJ%x immediately", 210 object->fscache.debug_id, 211 xobject->fscache.debug_id); 212 goto requeue; 213 } 214 215 /* otherwise we sleep until either the object we're waiting for 216 * is done, or the fscache_object is congested */ 217 wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); 218 init_wait(&wait); 219 requeue = false; 220 do { 221 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); 222 if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) 223 break; 224 225 requeue = fscache_object_sleep_till_congested(&timeout); 226 } while (timeout > 0 && !requeue); 227 finish_wait(wq, &wait); 228 229 if (requeue && 230 test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { 231 _debug("queue OBJ%x behind OBJ%x after wait", 232 object->fscache.debug_id, 233 xobject->fscache.debug_id); 234 goto requeue; 235 } 236 237 if (timeout <= 0) { 238 pr_err("\n"); 239 pr_err("Error: Overlong wait for old active object to go away\n"); 240 cachefiles_printk_object(object, xobject); 241 goto requeue; 242 } 243 } 244 245 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); 246 247 cache->cache.ops->put_object(&xobject->fscache, cachefiles_obj_put_wait_retry); 248 goto try_again; 249 250 requeue: 251 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); 252 cache->cache.ops->put_object(&xobject->fscache, cachefiles_obj_put_wait_timeo); 253 _leave(" = -ETIMEDOUT"); 254 return -ETIMEDOUT; 255 } 256 257 /* 258 * Mark an object as being inactive. 259 */ 260 void cachefiles_mark_object_inactive(struct cachefiles_cache *cache, 261 struct cachefiles_object *object, 262 blkcnt_t i_blocks) 263 { 264 struct dentry *dentry = object->dentry; 265 struct inode *inode = d_backing_inode(dentry); 266 267 trace_cachefiles_mark_inactive(object, dentry, inode); 268 269 write_lock(&cache->active_lock); 270 rb_erase(&object->active_node, &cache->active_nodes); 271 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); 272 write_unlock(&cache->active_lock); 273 274 wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); 275 276 /* This object can now be culled, so we need to let the daemon know 277 * that there is something it can remove if it needs to. 278 */ 279 atomic_long_add(i_blocks, &cache->b_released); 280 if (atomic_inc_return(&cache->f_released)) 281 cachefiles_state_changed(cache); 282 } 283 284 /* 285 * delete an object representation from the cache 286 * - file backed objects are unlinked 287 * - directory backed objects are stuffed into the graveyard for userspace to 288 * delete 289 * - unlocks the directory mutex 290 */ 291 static int cachefiles_bury_object(struct cachefiles_cache *cache, 292 struct cachefiles_object *object, 293 struct dentry *dir, 294 struct dentry *rep, 295 bool preemptive, 296 enum fscache_why_object_killed why) 297 { 298 struct dentry *grave, *trap; 299 struct path path, path_to_graveyard; 300 char nbuffer[8 + 8 + 1]; 301 int ret; 302 303 _enter(",'%pd','%pd'", dir, rep); 304 305 _debug("remove %p from %p", rep, dir); 306 307 /* non-directories can just be unlinked */ 308 if (!d_is_dir(rep)) { 309 _debug("unlink stale object"); 310 311 path.mnt = cache->mnt; 312 path.dentry = dir; 313 ret = security_path_unlink(&path, rep); 314 if (ret < 0) { 315 cachefiles_io_error(cache, "Unlink security error"); 316 } else { 317 trace_cachefiles_unlink(object, rep, why); 318 ret = vfs_unlink(d_inode(dir), rep, NULL); 319 320 if (preemptive) 321 cachefiles_mark_object_buried(cache, rep, why); 322 } 323 324 inode_unlock(d_inode(dir)); 325 326 if (ret == -EIO) 327 cachefiles_io_error(cache, "Unlink failed"); 328 329 _leave(" = %d", ret); 330 return ret; 331 } 332 333 /* directories have to be moved to the graveyard */ 334 _debug("move stale object to graveyard"); 335 inode_unlock(d_inode(dir)); 336 337 try_again: 338 /* first step is to make up a grave dentry in the graveyard */ 339 sprintf(nbuffer, "%08x%08x", 340 (uint32_t) get_seconds(), 341 (uint32_t) atomic_inc_return(&cache->gravecounter)); 342 343 /* do the multiway lock magic */ 344 trap = lock_rename(cache->graveyard, dir); 345 346 /* do some checks before getting the grave dentry */ 347 if (rep->d_parent != dir) { 348 /* the entry was probably culled when we dropped the parent dir 349 * lock */ 350 unlock_rename(cache->graveyard, dir); 351 _leave(" = 0 [culled?]"); 352 return 0; 353 } 354 355 if (!d_can_lookup(cache->graveyard)) { 356 unlock_rename(cache->graveyard, dir); 357 cachefiles_io_error(cache, "Graveyard no longer a directory"); 358 return -EIO; 359 } 360 361 if (trap == rep) { 362 unlock_rename(cache->graveyard, dir); 363 cachefiles_io_error(cache, "May not make directory loop"); 364 return -EIO; 365 } 366 367 if (d_mountpoint(rep)) { 368 unlock_rename(cache->graveyard, dir); 369 cachefiles_io_error(cache, "Mountpoint in cache"); 370 return -EIO; 371 } 372 373 grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); 374 if (IS_ERR(grave)) { 375 unlock_rename(cache->graveyard, dir); 376 377 if (PTR_ERR(grave) == -ENOMEM) { 378 _leave(" = -ENOMEM"); 379 return -ENOMEM; 380 } 381 382 cachefiles_io_error(cache, "Lookup error %ld", 383 PTR_ERR(grave)); 384 return -EIO; 385 } 386 387 if (d_is_positive(grave)) { 388 unlock_rename(cache->graveyard, dir); 389 dput(grave); 390 grave = NULL; 391 cond_resched(); 392 goto try_again; 393 } 394 395 if (d_mountpoint(grave)) { 396 unlock_rename(cache->graveyard, dir); 397 dput(grave); 398 cachefiles_io_error(cache, "Mountpoint in graveyard"); 399 return -EIO; 400 } 401 402 /* target should not be an ancestor of source */ 403 if (trap == grave) { 404 unlock_rename(cache->graveyard, dir); 405 dput(grave); 406 cachefiles_io_error(cache, "May not make directory loop"); 407 return -EIO; 408 } 409 410 /* attempt the rename */ 411 path.mnt = cache->mnt; 412 path.dentry = dir; 413 path_to_graveyard.mnt = cache->mnt; 414 path_to_graveyard.dentry = cache->graveyard; 415 ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0); 416 if (ret < 0) { 417 cachefiles_io_error(cache, "Rename security error %d", ret); 418 } else { 419 trace_cachefiles_rename(object, rep, grave, why); 420 ret = vfs_rename(d_inode(dir), rep, 421 d_inode(cache->graveyard), grave, NULL, 0); 422 if (ret != 0 && ret != -ENOMEM) 423 cachefiles_io_error(cache, 424 "Rename failed with error %d", ret); 425 426 if (preemptive) 427 cachefiles_mark_object_buried(cache, rep, why); 428 } 429 430 unlock_rename(cache->graveyard, dir); 431 dput(grave); 432 _leave(" = 0"); 433 return 0; 434 } 435 436 /* 437 * delete an object representation from the cache 438 */ 439 int cachefiles_delete_object(struct cachefiles_cache *cache, 440 struct cachefiles_object *object) 441 { 442 struct dentry *dir; 443 int ret; 444 445 _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); 446 447 ASSERT(object->dentry); 448 ASSERT(d_backing_inode(object->dentry)); 449 ASSERT(object->dentry->d_parent); 450 451 dir = dget_parent(object->dentry); 452 453 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 454 455 if (test_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->fscache.flags)) { 456 /* object allocation for the same key preemptively deleted this 457 * object's file so that it could create its own file */ 458 _debug("object preemptively buried"); 459 inode_unlock(d_inode(dir)); 460 ret = 0; 461 } else { 462 /* we need to check that our parent is _still_ our parent - it 463 * may have been renamed */ 464 if (dir == object->dentry->d_parent) { 465 ret = cachefiles_bury_object(cache, object, dir, 466 object->dentry, false, 467 FSCACHE_OBJECT_WAS_RETIRED); 468 } else { 469 /* it got moved, presumably by cachefilesd culling it, 470 * so it's no longer in the key path and we can ignore 471 * it */ 472 inode_unlock(d_inode(dir)); 473 ret = 0; 474 } 475 } 476 477 dput(dir); 478 _leave(" = %d", ret); 479 return ret; 480 } 481 482 /* 483 * walk from the parent object to the child object through the backing 484 * filesystem, creating directories as we go 485 */ 486 int cachefiles_walk_to_object(struct cachefiles_object *parent, 487 struct cachefiles_object *object, 488 const char *key, 489 struct cachefiles_xattr *auxdata) 490 { 491 struct cachefiles_cache *cache; 492 struct dentry *dir, *next = NULL; 493 struct inode *inode; 494 struct path path; 495 unsigned long start; 496 const char *name; 497 int ret, nlen; 498 499 _enter("OBJ%x{%p},OBJ%x,%s,", 500 parent->fscache.debug_id, parent->dentry, 501 object->fscache.debug_id, key); 502 503 cache = container_of(parent->fscache.cache, 504 struct cachefiles_cache, cache); 505 path.mnt = cache->mnt; 506 507 ASSERT(parent->dentry); 508 ASSERT(d_backing_inode(parent->dentry)); 509 510 if (!(d_is_dir(parent->dentry))) { 511 // TODO: convert file to dir 512 _leave("looking up in none directory"); 513 return -ENOBUFS; 514 } 515 516 dir = dget(parent->dentry); 517 518 advance: 519 /* attempt to transit the first directory component */ 520 name = key; 521 nlen = strlen(key); 522 523 /* key ends in a double NUL */ 524 key = key + nlen + 1; 525 if (!*key) 526 key = NULL; 527 528 lookup_again: 529 /* search the current directory for the element name */ 530 _debug("lookup '%s'", name); 531 532 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 533 534 start = jiffies; 535 next = lookup_one_len(name, dir, nlen); 536 cachefiles_hist(cachefiles_lookup_histogram, start); 537 if (IS_ERR(next)) { 538 trace_cachefiles_lookup(object, next, NULL); 539 goto lookup_error; 540 } 541 542 inode = d_backing_inode(next); 543 trace_cachefiles_lookup(object, next, inode); 544 _debug("next -> %p %s", next, inode ? "positive" : "negative"); 545 546 if (!key) 547 object->new = !inode; 548 549 /* if this element of the path doesn't exist, then the lookup phase 550 * failed, and we can release any readers in the certain knowledge that 551 * there's nothing for them to actually read */ 552 if (d_is_negative(next)) 553 fscache_object_lookup_negative(&object->fscache); 554 555 /* we need to create the object if it's negative */ 556 if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { 557 /* index objects and intervening tree levels must be subdirs */ 558 if (d_is_negative(next)) { 559 ret = cachefiles_has_space(cache, 1, 0); 560 if (ret < 0) 561 goto no_space_error; 562 563 path.dentry = dir; 564 ret = security_path_mkdir(&path, next, 0); 565 if (ret < 0) 566 goto create_error; 567 start = jiffies; 568 ret = vfs_mkdir(d_inode(dir), next, 0); 569 cachefiles_hist(cachefiles_mkdir_histogram, start); 570 if (!key) 571 trace_cachefiles_mkdir(object, next, ret); 572 if (ret < 0) 573 goto create_error; 574 575 ASSERT(d_backing_inode(next)); 576 577 _debug("mkdir -> %p{%p{ino=%lu}}", 578 next, d_backing_inode(next), d_backing_inode(next)->i_ino); 579 580 } else if (!d_can_lookup(next)) { 581 pr_err("inode %lu is not a directory\n", 582 d_backing_inode(next)->i_ino); 583 ret = -ENOBUFS; 584 goto error; 585 } 586 587 } else { 588 /* non-index objects start out life as files */ 589 if (d_is_negative(next)) { 590 ret = cachefiles_has_space(cache, 1, 0); 591 if (ret < 0) 592 goto no_space_error; 593 594 path.dentry = dir; 595 ret = security_path_mknod(&path, next, S_IFREG, 0); 596 if (ret < 0) 597 goto create_error; 598 start = jiffies; 599 ret = vfs_create(d_inode(dir), next, S_IFREG, true); 600 cachefiles_hist(cachefiles_create_histogram, start); 601 trace_cachefiles_create(object, next, ret); 602 if (ret < 0) 603 goto create_error; 604 605 ASSERT(d_backing_inode(next)); 606 607 _debug("create -> %p{%p{ino=%lu}}", 608 next, d_backing_inode(next), d_backing_inode(next)->i_ino); 609 610 } else if (!d_can_lookup(next) && 611 !d_is_reg(next) 612 ) { 613 pr_err("inode %lu is not a file or directory\n", 614 d_backing_inode(next)->i_ino); 615 ret = -ENOBUFS; 616 goto error; 617 } 618 } 619 620 /* process the next component */ 621 if (key) { 622 _debug("advance"); 623 inode_unlock(d_inode(dir)); 624 dput(dir); 625 dir = next; 626 next = NULL; 627 goto advance; 628 } 629 630 /* we've found the object we were looking for */ 631 object->dentry = next; 632 633 /* if we've found that the terminal object exists, then we need to 634 * check its attributes and delete it if it's out of date */ 635 if (!object->new) { 636 _debug("validate '%pd'", next); 637 638 ret = cachefiles_check_object_xattr(object, auxdata); 639 if (ret == -ESTALE) { 640 /* delete the object (the deleter drops the directory 641 * mutex) */ 642 object->dentry = NULL; 643 644 ret = cachefiles_bury_object(cache, object, dir, next, 645 true, 646 FSCACHE_OBJECT_IS_STALE); 647 dput(next); 648 next = NULL; 649 650 if (ret < 0) 651 goto delete_error; 652 653 _debug("redo lookup"); 654 fscache_object_retrying_stale(&object->fscache); 655 goto lookup_again; 656 } 657 } 658 659 /* note that we're now using this object */ 660 ret = cachefiles_mark_object_active(cache, object); 661 662 inode_unlock(d_inode(dir)); 663 dput(dir); 664 dir = NULL; 665 666 if (ret == -ETIMEDOUT) 667 goto mark_active_timed_out; 668 669 _debug("=== OBTAINED_OBJECT ==="); 670 671 if (object->new) { 672 /* attach data to a newly constructed terminal object */ 673 ret = cachefiles_set_object_xattr(object, auxdata); 674 if (ret < 0) 675 goto check_error; 676 } else { 677 /* always update the atime on an object we've just looked up 678 * (this is used to keep track of culling, and atimes are only 679 * updated by read, write and readdir but not lookup or 680 * open) */ 681 path.dentry = next; 682 touch_atime(&path); 683 } 684 685 /* open a file interface onto a data file */ 686 if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { 687 if (d_is_reg(object->dentry)) { 688 const struct address_space_operations *aops; 689 690 ret = -EPERM; 691 aops = d_backing_inode(object->dentry)->i_mapping->a_ops; 692 if (!aops->bmap) 693 goto check_error; 694 if (object->dentry->d_sb->s_blocksize > PAGE_SIZE) 695 goto check_error; 696 697 object->backer = object->dentry; 698 } else { 699 BUG(); // TODO: open file in data-class subdir 700 } 701 } 702 703 object->new = 0; 704 fscache_obtained_object(&object->fscache); 705 706 _leave(" = 0 [%lu]", d_backing_inode(object->dentry)->i_ino); 707 return 0; 708 709 no_space_error: 710 fscache_object_mark_killed(&object->fscache, FSCACHE_OBJECT_NO_SPACE); 711 create_error: 712 _debug("create error %d", ret); 713 if (ret == -EIO) 714 cachefiles_io_error(cache, "Create/mkdir failed"); 715 goto error; 716 717 mark_active_timed_out: 718 _debug("mark active timed out"); 719 goto release_dentry; 720 721 check_error: 722 _debug("check error %d", ret); 723 cachefiles_mark_object_inactive( 724 cache, object, d_backing_inode(object->dentry)->i_blocks); 725 release_dentry: 726 dput(object->dentry); 727 object->dentry = NULL; 728 goto error_out; 729 730 delete_error: 731 _debug("delete error %d", ret); 732 goto error_out2; 733 734 lookup_error: 735 _debug("lookup error %ld", PTR_ERR(next)); 736 ret = PTR_ERR(next); 737 if (ret == -EIO) 738 cachefiles_io_error(cache, "Lookup failed"); 739 next = NULL; 740 error: 741 inode_unlock(d_inode(dir)); 742 dput(next); 743 error_out2: 744 dput(dir); 745 error_out: 746 _leave(" = error %d", -ret); 747 return ret; 748 } 749 750 /* 751 * get a subdirectory 752 */ 753 struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 754 struct dentry *dir, 755 const char *dirname) 756 { 757 struct dentry *subdir; 758 unsigned long start; 759 struct path path; 760 int ret; 761 762 _enter(",,%s", dirname); 763 764 /* search the current directory for the element name */ 765 inode_lock(d_inode(dir)); 766 767 start = jiffies; 768 subdir = lookup_one_len(dirname, dir, strlen(dirname)); 769 cachefiles_hist(cachefiles_lookup_histogram, start); 770 if (IS_ERR(subdir)) { 771 if (PTR_ERR(subdir) == -ENOMEM) 772 goto nomem_d_alloc; 773 goto lookup_error; 774 } 775 776 _debug("subdir -> %p %s", 777 subdir, d_backing_inode(subdir) ? "positive" : "negative"); 778 779 /* we need to create the subdir if it doesn't exist yet */ 780 if (d_is_negative(subdir)) { 781 ret = cachefiles_has_space(cache, 1, 0); 782 if (ret < 0) 783 goto mkdir_error; 784 785 _debug("attempt mkdir"); 786 787 path.mnt = cache->mnt; 788 path.dentry = dir; 789 ret = security_path_mkdir(&path, subdir, 0700); 790 if (ret < 0) 791 goto mkdir_error; 792 ret = vfs_mkdir(d_inode(dir), subdir, 0700); 793 if (ret < 0) 794 goto mkdir_error; 795 796 ASSERT(d_backing_inode(subdir)); 797 798 _debug("mkdir -> %p{%p{ino=%lu}}", 799 subdir, 800 d_backing_inode(subdir), 801 d_backing_inode(subdir)->i_ino); 802 } 803 804 inode_unlock(d_inode(dir)); 805 806 /* we need to make sure the subdir is a directory */ 807 ASSERT(d_backing_inode(subdir)); 808 809 if (!d_can_lookup(subdir)) { 810 pr_err("%s is not a directory\n", dirname); 811 ret = -EIO; 812 goto check_error; 813 } 814 815 ret = -EPERM; 816 if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) || 817 !d_backing_inode(subdir)->i_op->lookup || 818 !d_backing_inode(subdir)->i_op->mkdir || 819 !d_backing_inode(subdir)->i_op->create || 820 !d_backing_inode(subdir)->i_op->rename || 821 !d_backing_inode(subdir)->i_op->rmdir || 822 !d_backing_inode(subdir)->i_op->unlink) 823 goto check_error; 824 825 _leave(" = [%lu]", d_backing_inode(subdir)->i_ino); 826 return subdir; 827 828 check_error: 829 dput(subdir); 830 _leave(" = %d [check]", ret); 831 return ERR_PTR(ret); 832 833 mkdir_error: 834 inode_unlock(d_inode(dir)); 835 dput(subdir); 836 pr_err("mkdir %s failed with error %d\n", dirname, ret); 837 return ERR_PTR(ret); 838 839 lookup_error: 840 inode_unlock(d_inode(dir)); 841 ret = PTR_ERR(subdir); 842 pr_err("Lookup %s failed with error %d\n", dirname, ret); 843 return ERR_PTR(ret); 844 845 nomem_d_alloc: 846 inode_unlock(d_inode(dir)); 847 _leave(" = -ENOMEM"); 848 return ERR_PTR(-ENOMEM); 849 } 850 851 /* 852 * find out if an object is in use or not 853 * - if finds object and it's not in use: 854 * - returns a pointer to the object and a reference on it 855 * - returns with the directory locked 856 */ 857 static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, 858 struct dentry *dir, 859 char *filename) 860 { 861 struct cachefiles_object *object; 862 struct rb_node *_n; 863 struct dentry *victim; 864 unsigned long start; 865 int ret; 866 867 //_enter(",%pd/,%s", 868 // dir, filename); 869 870 /* look up the victim */ 871 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 872 873 start = jiffies; 874 victim = lookup_one_len(filename, dir, strlen(filename)); 875 cachefiles_hist(cachefiles_lookup_histogram, start); 876 if (IS_ERR(victim)) 877 goto lookup_error; 878 879 //_debug("victim -> %p %s", 880 // victim, d_backing_inode(victim) ? "positive" : "negative"); 881 882 /* if the object is no longer there then we probably retired the object 883 * at the netfs's request whilst the cull was in progress 884 */ 885 if (d_is_negative(victim)) { 886 inode_unlock(d_inode(dir)); 887 dput(victim); 888 _leave(" = -ENOENT [absent]"); 889 return ERR_PTR(-ENOENT); 890 } 891 892 /* check to see if we're using this object */ 893 read_lock(&cache->active_lock); 894 895 _n = cache->active_nodes.rb_node; 896 897 while (_n) { 898 object = rb_entry(_n, struct cachefiles_object, active_node); 899 900 if (object->dentry > victim) 901 _n = _n->rb_left; 902 else if (object->dentry < victim) 903 _n = _n->rb_right; 904 else 905 goto object_in_use; 906 } 907 908 read_unlock(&cache->active_lock); 909 910 //_leave(" = %p", victim); 911 return victim; 912 913 object_in_use: 914 read_unlock(&cache->active_lock); 915 inode_unlock(d_inode(dir)); 916 dput(victim); 917 //_leave(" = -EBUSY [in use]"); 918 return ERR_PTR(-EBUSY); 919 920 lookup_error: 921 inode_unlock(d_inode(dir)); 922 ret = PTR_ERR(victim); 923 if (ret == -ENOENT) { 924 /* file or dir now absent - probably retired by netfs */ 925 _leave(" = -ESTALE [absent]"); 926 return ERR_PTR(-ESTALE); 927 } 928 929 if (ret == -EIO) { 930 cachefiles_io_error(cache, "Lookup failed"); 931 } else if (ret != -ENOMEM) { 932 pr_err("Internal error: %d\n", ret); 933 ret = -EIO; 934 } 935 936 _leave(" = %d", ret); 937 return ERR_PTR(ret); 938 } 939 940 /* 941 * cull an object if it's not in use 942 * - called only by cache manager daemon 943 */ 944 int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, 945 char *filename) 946 { 947 struct dentry *victim; 948 int ret; 949 950 _enter(",%pd/,%s", dir, filename); 951 952 victim = cachefiles_check_active(cache, dir, filename); 953 if (IS_ERR(victim)) 954 return PTR_ERR(victim); 955 956 _debug("victim -> %p %s", 957 victim, d_backing_inode(victim) ? "positive" : "negative"); 958 959 /* okay... the victim is not being used so we can cull it 960 * - start by marking it as stale 961 */ 962 _debug("victim is cullable"); 963 964 ret = cachefiles_remove_object_xattr(cache, victim); 965 if (ret < 0) 966 goto error_unlock; 967 968 /* actually remove the victim (drops the dir mutex) */ 969 _debug("bury"); 970 971 ret = cachefiles_bury_object(cache, NULL, dir, victim, false, 972 FSCACHE_OBJECT_WAS_CULLED); 973 if (ret < 0) 974 goto error; 975 976 dput(victim); 977 _leave(" = 0"); 978 return 0; 979 980 error_unlock: 981 inode_unlock(d_inode(dir)); 982 error: 983 dput(victim); 984 if (ret == -ENOENT) { 985 /* file or dir now absent - probably retired by netfs */ 986 _leave(" = -ESTALE [absent]"); 987 return -ESTALE; 988 } 989 990 if (ret != -ENOMEM) { 991 pr_err("Internal error: %d\n", ret); 992 ret = -EIO; 993 } 994 995 _leave(" = %d", ret); 996 return ret; 997 } 998 999 /* 1000 * find out if an object is in use or not 1001 * - called only by cache manager daemon 1002 * - returns -EBUSY or 0 to indicate whether an object is in use or not 1003 */ 1004 int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, 1005 char *filename) 1006 { 1007 struct dentry *victim; 1008 1009 //_enter(",%pd/,%s", 1010 // dir, filename); 1011 1012 victim = cachefiles_check_active(cache, dir, filename); 1013 if (IS_ERR(victim)) 1014 return PTR_ERR(victim); 1015 1016 inode_unlock(d_inode(dir)); 1017 dput(victim); 1018 //_leave(" = 0"); 1019 return 0; 1020 } 1021