1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* CacheFiles path walking and related routines 3 * 4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #include <linux/module.h> 9 #include <linux/sched.h> 10 #include <linux/file.h> 11 #include <linux/fs.h> 12 #include <linux/fsnotify.h> 13 #include <linux/quotaops.h> 14 #include <linux/xattr.h> 15 #include <linux/mount.h> 16 #include <linux/namei.h> 17 #include <linux/security.h> 18 #include <linux/slab.h> 19 #include "internal.h" 20 21 #define CACHEFILES_KEYBUF_SIZE 512 22 23 /* 24 * dump debugging info about an object 25 */ 26 static noinline 27 void __cachefiles_printk_object(struct cachefiles_object *object, 28 const char *prefix) 29 { 30 struct fscache_cookie *cookie; 31 const u8 *k; 32 unsigned loop; 33 34 pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id); 35 pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n", 36 prefix, object->fscache.state->name, 37 object->fscache.flags, work_busy(&object->fscache.work), 38 object->fscache.events, object->fscache.event_mask); 39 pr_err("%sops=%u inp=%u exc=%u\n", 40 prefix, object->fscache.n_ops, object->fscache.n_in_progress, 41 object->fscache.n_exclusive); 42 pr_err("%sparent=%p\n", 43 prefix, object->fscache.parent); 44 45 spin_lock(&object->fscache.lock); 46 cookie = object->fscache.cookie; 47 if (cookie) { 48 pr_err("%scookie=%p [pr=%p nd=%p fl=%lx]\n", 49 prefix, 50 object->fscache.cookie, 51 object->fscache.cookie->parent, 52 object->fscache.cookie->netfs_data, 53 object->fscache.cookie->flags); 54 pr_err("%skey=[%u] '", prefix, cookie->key_len); 55 k = (cookie->key_len <= sizeof(cookie->inline_key)) ? 56 cookie->inline_key : cookie->key; 57 for (loop = 0; loop < cookie->key_len; loop++) 58 pr_cont("%02x", k[loop]); 59 pr_cont("'\n"); 60 } else { 61 pr_err("%scookie=NULL\n", prefix); 62 } 63 spin_unlock(&object->fscache.lock); 64 } 65 66 /* 67 * dump debugging info about a pair of objects 68 */ 69 static noinline void cachefiles_printk_object(struct cachefiles_object *object, 70 struct cachefiles_object *xobject) 71 { 72 if (object) 73 __cachefiles_printk_object(object, ""); 74 if (xobject) 75 __cachefiles_printk_object(xobject, "x"); 76 } 77 78 /* 79 * mark the owner of a dentry, if there is one, to indicate that that dentry 80 * has been preemptively deleted 81 * - the caller must hold the i_mutex on the dentry's parent as required to 82 * call vfs_unlink(), vfs_rmdir() or vfs_rename() 83 */ 84 static void cachefiles_mark_object_buried(struct cachefiles_cache *cache, 85 struct dentry *dentry, 86 enum fscache_why_object_killed why) 87 { 88 struct cachefiles_object *object; 89 struct rb_node *p; 90 91 _enter(",'%pd'", dentry); 92 93 write_lock(&cache->active_lock); 94 95 p = cache->active_nodes.rb_node; 96 while (p) { 97 object = rb_entry(p, struct cachefiles_object, active_node); 98 if (object->dentry > dentry) 99 p = p->rb_left; 100 else if (object->dentry < dentry) 101 p = p->rb_right; 102 else 103 goto found_dentry; 104 } 105 106 write_unlock(&cache->active_lock); 107 trace_cachefiles_mark_buried(NULL, dentry, why); 108 _leave(" [no owner]"); 109 return; 110 111 /* found the dentry for */ 112 found_dentry: 113 kdebug("preemptive burial: OBJ%x [%s] %p", 114 object->fscache.debug_id, 115 object->fscache.state->name, 116 dentry); 117 118 trace_cachefiles_mark_buried(object, dentry, why); 119 120 if (fscache_object_is_live(&object->fscache)) { 121 pr_err("\n"); 122 pr_err("Error: Can't preemptively bury live object\n"); 123 cachefiles_printk_object(object, NULL); 124 } else { 125 if (why != FSCACHE_OBJECT_IS_STALE) 126 fscache_object_mark_killed(&object->fscache, why); 127 } 128 129 write_unlock(&cache->active_lock); 130 _leave(" [owner marked]"); 131 } 132 133 /* 134 * record the fact that an object is now active 135 */ 136 static int cachefiles_mark_object_active(struct cachefiles_cache *cache, 137 struct cachefiles_object *object) 138 { 139 struct cachefiles_object *xobject; 140 struct rb_node **_p, *_parent = NULL; 141 struct dentry *dentry; 142 143 _enter(",%p", object); 144 145 try_again: 146 write_lock(&cache->active_lock); 147 148 dentry = object->dentry; 149 trace_cachefiles_mark_active(object, dentry); 150 151 if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { 152 pr_err("Error: Object already active\n"); 153 cachefiles_printk_object(object, NULL); 154 BUG(); 155 } 156 157 _p = &cache->active_nodes.rb_node; 158 while (*_p) { 159 _parent = *_p; 160 xobject = rb_entry(_parent, 161 struct cachefiles_object, active_node); 162 163 ASSERT(xobject != object); 164 165 if (xobject->dentry > dentry) 166 _p = &(*_p)->rb_left; 167 else if (xobject->dentry < dentry) 168 _p = &(*_p)->rb_right; 169 else 170 goto wait_for_old_object; 171 } 172 173 rb_link_node(&object->active_node, _parent, _p); 174 rb_insert_color(&object->active_node, &cache->active_nodes); 175 176 write_unlock(&cache->active_lock); 177 _leave(" = 0"); 178 return 0; 179 180 /* an old object from a previous incarnation is hogging the slot - we 181 * need to wait for it to be destroyed */ 182 wait_for_old_object: 183 trace_cachefiles_wait_active(object, dentry, xobject); 184 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); 185 186 if (fscache_object_is_live(&xobject->fscache)) { 187 pr_err("\n"); 188 pr_err("Error: Unexpected object collision\n"); 189 cachefiles_printk_object(object, xobject); 190 } 191 atomic_inc(&xobject->usage); 192 write_unlock(&cache->active_lock); 193 194 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { 195 wait_queue_head_t *wq; 196 197 signed long timeout = 60 * HZ; 198 wait_queue_entry_t wait; 199 bool requeue; 200 201 /* if the object we're waiting for is queued for processing, 202 * then just put ourselves on the queue behind it */ 203 if (work_pending(&xobject->fscache.work)) { 204 _debug("queue OBJ%x behind OBJ%x immediately", 205 object->fscache.debug_id, 206 xobject->fscache.debug_id); 207 goto requeue; 208 } 209 210 /* otherwise we sleep until either the object we're waiting for 211 * is done, or the fscache_object is congested */ 212 wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); 213 init_wait(&wait); 214 requeue = false; 215 do { 216 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); 217 if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) 218 break; 219 220 requeue = fscache_object_sleep_till_congested(&timeout); 221 } while (timeout > 0 && !requeue); 222 finish_wait(wq, &wait); 223 224 if (requeue && 225 test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { 226 _debug("queue OBJ%x behind OBJ%x after wait", 227 object->fscache.debug_id, 228 xobject->fscache.debug_id); 229 goto requeue; 230 } 231 232 if (timeout <= 0) { 233 pr_err("\n"); 234 pr_err("Error: Overlong wait for old active object to go away\n"); 235 cachefiles_printk_object(object, xobject); 236 goto requeue; 237 } 238 } 239 240 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); 241 242 cache->cache.ops->put_object(&xobject->fscache, 243 (enum fscache_obj_ref_trace)cachefiles_obj_put_wait_retry); 244 goto try_again; 245 246 requeue: 247 cache->cache.ops->put_object(&xobject->fscache, 248 (enum fscache_obj_ref_trace)cachefiles_obj_put_wait_timeo); 249 _leave(" = -ETIMEDOUT"); 250 return -ETIMEDOUT; 251 } 252 253 /* 254 * Mark an object as being inactive. 255 */ 256 void cachefiles_mark_object_inactive(struct cachefiles_cache *cache, 257 struct cachefiles_object *object, 258 blkcnt_t i_blocks) 259 { 260 struct dentry *dentry = object->dentry; 261 struct inode *inode = d_backing_inode(dentry); 262 263 trace_cachefiles_mark_inactive(object, dentry, inode); 264 265 write_lock(&cache->active_lock); 266 rb_erase(&object->active_node, &cache->active_nodes); 267 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); 268 write_unlock(&cache->active_lock); 269 270 wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); 271 272 /* This object can now be culled, so we need to let the daemon know 273 * that there is something it can remove if it needs to. 274 */ 275 atomic_long_add(i_blocks, &cache->b_released); 276 if (atomic_inc_return(&cache->f_released)) 277 cachefiles_state_changed(cache); 278 } 279 280 /* 281 * delete an object representation from the cache 282 * - file backed objects are unlinked 283 * - directory backed objects are stuffed into the graveyard for userspace to 284 * delete 285 * - unlocks the directory mutex 286 */ 287 static int cachefiles_bury_object(struct cachefiles_cache *cache, 288 struct cachefiles_object *object, 289 struct dentry *dir, 290 struct dentry *rep, 291 bool preemptive, 292 enum fscache_why_object_killed why) 293 { 294 struct dentry *grave, *trap; 295 struct path path, path_to_graveyard; 296 char nbuffer[8 + 8 + 1]; 297 int ret; 298 299 _enter(",'%pd','%pd'", dir, rep); 300 301 _debug("remove %p from %p", rep, dir); 302 303 /* non-directories can just be unlinked */ 304 if (!d_is_dir(rep)) { 305 _debug("unlink stale object"); 306 307 path.mnt = cache->mnt; 308 path.dentry = dir; 309 ret = security_path_unlink(&path, rep); 310 if (ret < 0) { 311 cachefiles_io_error(cache, "Unlink security error"); 312 } else { 313 trace_cachefiles_unlink(object, rep, why); 314 ret = vfs_unlink(d_inode(dir), rep, NULL); 315 316 if (preemptive) 317 cachefiles_mark_object_buried(cache, rep, why); 318 } 319 320 inode_unlock(d_inode(dir)); 321 322 if (ret == -EIO) 323 cachefiles_io_error(cache, "Unlink failed"); 324 325 _leave(" = %d", ret); 326 return ret; 327 } 328 329 /* directories have to be moved to the graveyard */ 330 _debug("move stale object to graveyard"); 331 inode_unlock(d_inode(dir)); 332 333 try_again: 334 /* first step is to make up a grave dentry in the graveyard */ 335 sprintf(nbuffer, "%08x%08x", 336 (uint32_t) ktime_get_real_seconds(), 337 (uint32_t) atomic_inc_return(&cache->gravecounter)); 338 339 /* do the multiway lock magic */ 340 trap = lock_rename(cache->graveyard, dir); 341 342 /* do some checks before getting the grave dentry */ 343 if (rep->d_parent != dir || IS_DEADDIR(d_inode(rep))) { 344 /* the entry was probably culled when we dropped the parent dir 345 * lock */ 346 unlock_rename(cache->graveyard, dir); 347 _leave(" = 0 [culled?]"); 348 return 0; 349 } 350 351 if (!d_can_lookup(cache->graveyard)) { 352 unlock_rename(cache->graveyard, dir); 353 cachefiles_io_error(cache, "Graveyard no longer a directory"); 354 return -EIO; 355 } 356 357 if (trap == rep) { 358 unlock_rename(cache->graveyard, dir); 359 cachefiles_io_error(cache, "May not make directory loop"); 360 return -EIO; 361 } 362 363 if (d_mountpoint(rep)) { 364 unlock_rename(cache->graveyard, dir); 365 cachefiles_io_error(cache, "Mountpoint in cache"); 366 return -EIO; 367 } 368 369 grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); 370 if (IS_ERR(grave)) { 371 unlock_rename(cache->graveyard, dir); 372 373 if (PTR_ERR(grave) == -ENOMEM) { 374 _leave(" = -ENOMEM"); 375 return -ENOMEM; 376 } 377 378 cachefiles_io_error(cache, "Lookup error %ld", 379 PTR_ERR(grave)); 380 return -EIO; 381 } 382 383 if (d_is_positive(grave)) { 384 unlock_rename(cache->graveyard, dir); 385 dput(grave); 386 grave = NULL; 387 cond_resched(); 388 goto try_again; 389 } 390 391 if (d_mountpoint(grave)) { 392 unlock_rename(cache->graveyard, dir); 393 dput(grave); 394 cachefiles_io_error(cache, "Mountpoint in graveyard"); 395 return -EIO; 396 } 397 398 /* target should not be an ancestor of source */ 399 if (trap == grave) { 400 unlock_rename(cache->graveyard, dir); 401 dput(grave); 402 cachefiles_io_error(cache, "May not make directory loop"); 403 return -EIO; 404 } 405 406 /* attempt the rename */ 407 path.mnt = cache->mnt; 408 path.dentry = dir; 409 path_to_graveyard.mnt = cache->mnt; 410 path_to_graveyard.dentry = cache->graveyard; 411 ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0); 412 if (ret < 0) { 413 cachefiles_io_error(cache, "Rename security error %d", ret); 414 } else { 415 struct renamedata rd = { 416 .old_dir = d_inode(dir), 417 .old_dentry = rep, 418 .new_dir = d_inode(cache->graveyard), 419 .new_dentry = grave, 420 }; 421 trace_cachefiles_rename(object, rep, grave, why); 422 ret = vfs_rename(&rd); 423 if (ret != 0 && ret != -ENOMEM) 424 cachefiles_io_error(cache, 425 "Rename failed with error %d", ret); 426 427 if (preemptive) 428 cachefiles_mark_object_buried(cache, rep, why); 429 } 430 431 unlock_rename(cache->graveyard, dir); 432 dput(grave); 433 _leave(" = 0"); 434 return 0; 435 } 436 437 /* 438 * delete an object representation from the cache 439 */ 440 int cachefiles_delete_object(struct cachefiles_cache *cache, 441 struct cachefiles_object *object) 442 { 443 struct dentry *dir; 444 int ret; 445 446 _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); 447 448 ASSERT(object->dentry); 449 ASSERT(d_backing_inode(object->dentry)); 450 ASSERT(object->dentry->d_parent); 451 452 dir = dget_parent(object->dentry); 453 454 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 455 456 if (test_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->fscache.flags)) { 457 /* object allocation for the same key preemptively deleted this 458 * object's file so that it could create its own file */ 459 _debug("object preemptively buried"); 460 inode_unlock(d_inode(dir)); 461 ret = 0; 462 } else { 463 /* we need to check that our parent is _still_ our parent - it 464 * may have been renamed */ 465 if (dir == object->dentry->d_parent) { 466 ret = cachefiles_bury_object(cache, object, dir, 467 object->dentry, false, 468 FSCACHE_OBJECT_WAS_RETIRED); 469 } else { 470 /* it got moved, presumably by cachefilesd culling it, 471 * so it's no longer in the key path and we can ignore 472 * it */ 473 inode_unlock(d_inode(dir)); 474 ret = 0; 475 } 476 } 477 478 dput(dir); 479 _leave(" = %d", ret); 480 return ret; 481 } 482 483 /* 484 * walk from the parent object to the child object through the backing 485 * filesystem, creating directories as we go 486 */ 487 int cachefiles_walk_to_object(struct cachefiles_object *parent, 488 struct cachefiles_object *object, 489 const char *key, 490 struct cachefiles_xattr *auxdata) 491 { 492 struct cachefiles_cache *cache; 493 struct dentry *dir, *next = NULL; 494 struct inode *inode; 495 struct path path; 496 unsigned long start; 497 const char *name; 498 int ret, nlen; 499 500 _enter("OBJ%x{%p},OBJ%x,%s,", 501 parent->fscache.debug_id, parent->dentry, 502 object->fscache.debug_id, key); 503 504 cache = container_of(parent->fscache.cache, 505 struct cachefiles_cache, cache); 506 path.mnt = cache->mnt; 507 508 ASSERT(parent->dentry); 509 ASSERT(d_backing_inode(parent->dentry)); 510 511 if (!(d_is_dir(parent->dentry))) { 512 // TODO: convert file to dir 513 _leave("looking up in none directory"); 514 return -ENOBUFS; 515 } 516 517 dir = dget(parent->dentry); 518 519 advance: 520 /* attempt to transit the first directory component */ 521 name = key; 522 nlen = strlen(key); 523 524 /* key ends in a double NUL */ 525 key = key + nlen + 1; 526 if (!*key) 527 key = NULL; 528 529 lookup_again: 530 /* search the current directory for the element name */ 531 _debug("lookup '%s'", name); 532 533 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 534 535 start = jiffies; 536 next = lookup_one_len(name, dir, nlen); 537 cachefiles_hist(cachefiles_lookup_histogram, start); 538 if (IS_ERR(next)) { 539 trace_cachefiles_lookup(object, next, NULL); 540 goto lookup_error; 541 } 542 543 inode = d_backing_inode(next); 544 trace_cachefiles_lookup(object, next, inode); 545 _debug("next -> %p %s", next, inode ? "positive" : "negative"); 546 547 if (!key) 548 object->new = !inode; 549 550 /* if this element of the path doesn't exist, then the lookup phase 551 * failed, and we can release any readers in the certain knowledge that 552 * there's nothing for them to actually read */ 553 if (d_is_negative(next)) 554 fscache_object_lookup_negative(&object->fscache); 555 556 /* we need to create the object if it's negative */ 557 if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { 558 /* index objects and intervening tree levels must be subdirs */ 559 if (d_is_negative(next)) { 560 ret = cachefiles_has_space(cache, 1, 0); 561 if (ret < 0) 562 goto no_space_error; 563 564 path.dentry = dir; 565 ret = security_path_mkdir(&path, next, 0); 566 if (ret < 0) 567 goto create_error; 568 start = jiffies; 569 ret = vfs_mkdir(d_inode(dir), next, 0); 570 cachefiles_hist(cachefiles_mkdir_histogram, start); 571 if (!key) 572 trace_cachefiles_mkdir(object, next, ret); 573 if (ret < 0) 574 goto create_error; 575 576 if (unlikely(d_unhashed(next))) { 577 dput(next); 578 inode_unlock(d_inode(dir)); 579 goto lookup_again; 580 } 581 ASSERT(d_backing_inode(next)); 582 583 _debug("mkdir -> %p{%p{ino=%lu}}", 584 next, d_backing_inode(next), d_backing_inode(next)->i_ino); 585 586 } else if (!d_can_lookup(next)) { 587 pr_err("inode %lu is not a directory\n", 588 d_backing_inode(next)->i_ino); 589 ret = -ENOBUFS; 590 goto error; 591 } 592 593 } else { 594 /* non-index objects start out life as files */ 595 if (d_is_negative(next)) { 596 ret = cachefiles_has_space(cache, 1, 0); 597 if (ret < 0) 598 goto no_space_error; 599 600 path.dentry = dir; 601 ret = security_path_mknod(&path, next, S_IFREG, 0); 602 if (ret < 0) 603 goto create_error; 604 start = jiffies; 605 ret = vfs_create(d_inode(dir), next, S_IFREG, true); 606 cachefiles_hist(cachefiles_create_histogram, start); 607 trace_cachefiles_create(object, next, ret); 608 if (ret < 0) 609 goto create_error; 610 611 ASSERT(d_backing_inode(next)); 612 613 _debug("create -> %p{%p{ino=%lu}}", 614 next, d_backing_inode(next), d_backing_inode(next)->i_ino); 615 616 } else if (!d_can_lookup(next) && 617 !d_is_reg(next) 618 ) { 619 pr_err("inode %lu is not a file or directory\n", 620 d_backing_inode(next)->i_ino); 621 ret = -ENOBUFS; 622 goto error; 623 } 624 } 625 626 /* process the next component */ 627 if (key) { 628 _debug("advance"); 629 inode_unlock(d_inode(dir)); 630 dput(dir); 631 dir = next; 632 next = NULL; 633 goto advance; 634 } 635 636 /* we've found the object we were looking for */ 637 object->dentry = next; 638 639 /* if we've found that the terminal object exists, then we need to 640 * check its attributes and delete it if it's out of date */ 641 if (!object->new) { 642 _debug("validate '%pd'", next); 643 644 ret = cachefiles_check_object_xattr(object, auxdata); 645 if (ret == -ESTALE) { 646 /* delete the object (the deleter drops the directory 647 * mutex) */ 648 object->dentry = NULL; 649 650 ret = cachefiles_bury_object(cache, object, dir, next, 651 true, 652 FSCACHE_OBJECT_IS_STALE); 653 dput(next); 654 next = NULL; 655 656 if (ret < 0) 657 goto delete_error; 658 659 _debug("redo lookup"); 660 fscache_object_retrying_stale(&object->fscache); 661 goto lookup_again; 662 } 663 } 664 665 /* note that we're now using this object */ 666 ret = cachefiles_mark_object_active(cache, object); 667 668 inode_unlock(d_inode(dir)); 669 dput(dir); 670 dir = NULL; 671 672 if (ret == -ETIMEDOUT) 673 goto mark_active_timed_out; 674 675 _debug("=== OBTAINED_OBJECT ==="); 676 677 if (object->new) { 678 /* attach data to a newly constructed terminal object */ 679 ret = cachefiles_set_object_xattr(object, auxdata); 680 if (ret < 0) 681 goto check_error; 682 } else { 683 /* always update the atime on an object we've just looked up 684 * (this is used to keep track of culling, and atimes are only 685 * updated by read, write and readdir but not lookup or 686 * open) */ 687 path.dentry = next; 688 touch_atime(&path); 689 } 690 691 /* open a file interface onto a data file */ 692 if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { 693 if (d_is_reg(object->dentry)) { 694 const struct address_space_operations *aops; 695 696 ret = -EPERM; 697 aops = d_backing_inode(object->dentry)->i_mapping->a_ops; 698 if (!aops->bmap) 699 goto check_error; 700 if (object->dentry->d_sb->s_blocksize > PAGE_SIZE) 701 goto check_error; 702 703 object->backer = object->dentry; 704 } else { 705 BUG(); // TODO: open file in data-class subdir 706 } 707 } 708 709 object->new = 0; 710 fscache_obtained_object(&object->fscache); 711 712 _leave(" = 0 [%lu]", d_backing_inode(object->dentry)->i_ino); 713 return 0; 714 715 no_space_error: 716 fscache_object_mark_killed(&object->fscache, FSCACHE_OBJECT_NO_SPACE); 717 create_error: 718 _debug("create error %d", ret); 719 if (ret == -EIO) 720 cachefiles_io_error(cache, "Create/mkdir failed"); 721 goto error; 722 723 mark_active_timed_out: 724 _debug("mark active timed out"); 725 goto release_dentry; 726 727 check_error: 728 _debug("check error %d", ret); 729 cachefiles_mark_object_inactive( 730 cache, object, d_backing_inode(object->dentry)->i_blocks); 731 release_dentry: 732 dput(object->dentry); 733 object->dentry = NULL; 734 goto error_out; 735 736 delete_error: 737 _debug("delete error %d", ret); 738 goto error_out2; 739 740 lookup_error: 741 _debug("lookup error %ld", PTR_ERR(next)); 742 ret = PTR_ERR(next); 743 if (ret == -EIO) 744 cachefiles_io_error(cache, "Lookup failed"); 745 next = NULL; 746 error: 747 inode_unlock(d_inode(dir)); 748 dput(next); 749 error_out2: 750 dput(dir); 751 error_out: 752 _leave(" = error %d", -ret); 753 return ret; 754 } 755 756 /* 757 * get a subdirectory 758 */ 759 struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 760 struct dentry *dir, 761 const char *dirname) 762 { 763 struct dentry *subdir; 764 unsigned long start; 765 struct path path; 766 int ret; 767 768 _enter(",,%s", dirname); 769 770 /* search the current directory for the element name */ 771 inode_lock(d_inode(dir)); 772 773 retry: 774 start = jiffies; 775 subdir = lookup_one_len(dirname, dir, strlen(dirname)); 776 cachefiles_hist(cachefiles_lookup_histogram, start); 777 if (IS_ERR(subdir)) { 778 if (PTR_ERR(subdir) == -ENOMEM) 779 goto nomem_d_alloc; 780 goto lookup_error; 781 } 782 783 _debug("subdir -> %p %s", 784 subdir, d_backing_inode(subdir) ? "positive" : "negative"); 785 786 /* we need to create the subdir if it doesn't exist yet */ 787 if (d_is_negative(subdir)) { 788 ret = cachefiles_has_space(cache, 1, 0); 789 if (ret < 0) 790 goto mkdir_error; 791 792 _debug("attempt mkdir"); 793 794 path.mnt = cache->mnt; 795 path.dentry = dir; 796 ret = security_path_mkdir(&path, subdir, 0700); 797 if (ret < 0) 798 goto mkdir_error; 799 ret = vfs_mkdir(d_inode(dir), subdir, 0700); 800 if (ret < 0) 801 goto mkdir_error; 802 803 if (unlikely(d_unhashed(subdir))) { 804 dput(subdir); 805 goto retry; 806 } 807 ASSERT(d_backing_inode(subdir)); 808 809 _debug("mkdir -> %p{%p{ino=%lu}}", 810 subdir, 811 d_backing_inode(subdir), 812 d_backing_inode(subdir)->i_ino); 813 } 814 815 inode_unlock(d_inode(dir)); 816 817 /* we need to make sure the subdir is a directory */ 818 ASSERT(d_backing_inode(subdir)); 819 820 if (!d_can_lookup(subdir)) { 821 pr_err("%s is not a directory\n", dirname); 822 ret = -EIO; 823 goto check_error; 824 } 825 826 ret = -EPERM; 827 if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) || 828 !d_backing_inode(subdir)->i_op->lookup || 829 !d_backing_inode(subdir)->i_op->mkdir || 830 !d_backing_inode(subdir)->i_op->create || 831 !d_backing_inode(subdir)->i_op->rename || 832 !d_backing_inode(subdir)->i_op->rmdir || 833 !d_backing_inode(subdir)->i_op->unlink) 834 goto check_error; 835 836 _leave(" = [%lu]", d_backing_inode(subdir)->i_ino); 837 return subdir; 838 839 check_error: 840 dput(subdir); 841 _leave(" = %d [check]", ret); 842 return ERR_PTR(ret); 843 844 mkdir_error: 845 inode_unlock(d_inode(dir)); 846 dput(subdir); 847 pr_err("mkdir %s failed with error %d\n", dirname, ret); 848 return ERR_PTR(ret); 849 850 lookup_error: 851 inode_unlock(d_inode(dir)); 852 ret = PTR_ERR(subdir); 853 pr_err("Lookup %s failed with error %d\n", dirname, ret); 854 return ERR_PTR(ret); 855 856 nomem_d_alloc: 857 inode_unlock(d_inode(dir)); 858 _leave(" = -ENOMEM"); 859 return ERR_PTR(-ENOMEM); 860 } 861 862 /* 863 * find out if an object is in use or not 864 * - if finds object and it's not in use: 865 * - returns a pointer to the object and a reference on it 866 * - returns with the directory locked 867 */ 868 static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, 869 struct dentry *dir, 870 char *filename) 871 { 872 struct cachefiles_object *object; 873 struct rb_node *_n; 874 struct dentry *victim; 875 unsigned long start; 876 int ret; 877 878 //_enter(",%pd/,%s", 879 // dir, filename); 880 881 /* look up the victim */ 882 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 883 884 start = jiffies; 885 victim = lookup_one_len(filename, dir, strlen(filename)); 886 cachefiles_hist(cachefiles_lookup_histogram, start); 887 if (IS_ERR(victim)) 888 goto lookup_error; 889 890 //_debug("victim -> %p %s", 891 // victim, d_backing_inode(victim) ? "positive" : "negative"); 892 893 /* if the object is no longer there then we probably retired the object 894 * at the netfs's request whilst the cull was in progress 895 */ 896 if (d_is_negative(victim)) { 897 inode_unlock(d_inode(dir)); 898 dput(victim); 899 _leave(" = -ENOENT [absent]"); 900 return ERR_PTR(-ENOENT); 901 } 902 903 /* check to see if we're using this object */ 904 read_lock(&cache->active_lock); 905 906 _n = cache->active_nodes.rb_node; 907 908 while (_n) { 909 object = rb_entry(_n, struct cachefiles_object, active_node); 910 911 if (object->dentry > victim) 912 _n = _n->rb_left; 913 else if (object->dentry < victim) 914 _n = _n->rb_right; 915 else 916 goto object_in_use; 917 } 918 919 read_unlock(&cache->active_lock); 920 921 //_leave(" = %p", victim); 922 return victim; 923 924 object_in_use: 925 read_unlock(&cache->active_lock); 926 inode_unlock(d_inode(dir)); 927 dput(victim); 928 //_leave(" = -EBUSY [in use]"); 929 return ERR_PTR(-EBUSY); 930 931 lookup_error: 932 inode_unlock(d_inode(dir)); 933 ret = PTR_ERR(victim); 934 if (ret == -ENOENT) { 935 /* file or dir now absent - probably retired by netfs */ 936 _leave(" = -ESTALE [absent]"); 937 return ERR_PTR(-ESTALE); 938 } 939 940 if (ret == -EIO) { 941 cachefiles_io_error(cache, "Lookup failed"); 942 } else if (ret != -ENOMEM) { 943 pr_err("Internal error: %d\n", ret); 944 ret = -EIO; 945 } 946 947 _leave(" = %d", ret); 948 return ERR_PTR(ret); 949 } 950 951 /* 952 * cull an object if it's not in use 953 * - called only by cache manager daemon 954 */ 955 int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, 956 char *filename) 957 { 958 struct dentry *victim; 959 int ret; 960 961 _enter(",%pd/,%s", dir, filename); 962 963 victim = cachefiles_check_active(cache, dir, filename); 964 if (IS_ERR(victim)) 965 return PTR_ERR(victim); 966 967 _debug("victim -> %p %s", 968 victim, d_backing_inode(victim) ? "positive" : "negative"); 969 970 /* okay... the victim is not being used so we can cull it 971 * - start by marking it as stale 972 */ 973 _debug("victim is cullable"); 974 975 ret = cachefiles_remove_object_xattr(cache, victim); 976 if (ret < 0) 977 goto error_unlock; 978 979 /* actually remove the victim (drops the dir mutex) */ 980 _debug("bury"); 981 982 ret = cachefiles_bury_object(cache, NULL, dir, victim, false, 983 FSCACHE_OBJECT_WAS_CULLED); 984 if (ret < 0) 985 goto error; 986 987 dput(victim); 988 _leave(" = 0"); 989 return 0; 990 991 error_unlock: 992 inode_unlock(d_inode(dir)); 993 error: 994 dput(victim); 995 if (ret == -ENOENT) { 996 /* file or dir now absent - probably retired by netfs */ 997 _leave(" = -ESTALE [absent]"); 998 return -ESTALE; 999 } 1000 1001 if (ret != -ENOMEM) { 1002 pr_err("Internal error: %d\n", ret); 1003 ret = -EIO; 1004 } 1005 1006 _leave(" = %d", ret); 1007 return ret; 1008 } 1009 1010 /* 1011 * find out if an object is in use or not 1012 * - called only by cache manager daemon 1013 * - returns -EBUSY or 0 to indicate whether an object is in use or not 1014 */ 1015 int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, 1016 char *filename) 1017 { 1018 struct dentry *victim; 1019 1020 //_enter(",%pd/,%s", 1021 // dir, filename); 1022 1023 victim = cachefiles_check_active(cache, dir, filename); 1024 if (IS_ERR(victim)) 1025 return PTR_ERR(victim); 1026 1027 inode_unlock(d_inode(dir)); 1028 dput(victim); 1029 //_leave(" = 0"); 1030 return 0; 1031 } 1032