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 */ 26static noinline 27void __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 */ 69static 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 */ 84static 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 */ 112found_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 */ 136static 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 145try_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 */ 182wait_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 246requeue: 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 */ 256void 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 */ 287static 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 333try_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 trace_cachefiles_rename(object, rep, grave, why); 416 ret = vfs_rename(d_inode(dir), rep, 417 d_inode(cache->graveyard), grave, NULL, 0); 418 if (ret != 0 && ret != -ENOMEM) 419 cachefiles_io_error(cache, 420 "Rename failed with error %d", ret); 421 422 if (preemptive) 423 cachefiles_mark_object_buried(cache, rep, why); 424 } 425 426 unlock_rename(cache->graveyard, dir); 427 dput(grave); 428 _leave(" = 0"); 429 return 0; 430} 431 432/* 433 * delete an object representation from the cache 434 */ 435int cachefiles_delete_object(struct cachefiles_cache *cache, 436 struct cachefiles_object *object) 437{ 438 struct dentry *dir; 439 int ret; 440 441 _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); 442 443 ASSERT(object->dentry); 444 ASSERT(d_backing_inode(object->dentry)); 445 ASSERT(object->dentry->d_parent); 446 447 dir = dget_parent(object->dentry); 448 449 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 450 451 if (test_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->fscache.flags)) { 452 /* object allocation for the same key preemptively deleted this 453 * object's file so that it could create its own file */ 454 _debug("object preemptively buried"); 455 inode_unlock(d_inode(dir)); 456 ret = 0; 457 } else { 458 /* we need to check that our parent is _still_ our parent - it 459 * may have been renamed */ 460 if (dir == object->dentry->d_parent) { 461 ret = cachefiles_bury_object(cache, object, dir, 462 object->dentry, false, 463 FSCACHE_OBJECT_WAS_RETIRED); 464 } else { 465 /* it got moved, presumably by cachefilesd culling it, 466 * so it's no longer in the key path and we can ignore 467 * it */ 468 inode_unlock(d_inode(dir)); 469 ret = 0; 470 } 471 } 472 473 dput(dir); 474 _leave(" = %d", ret); 475 return ret; 476} 477 478/* 479 * walk from the parent object to the child object through the backing 480 * filesystem, creating directories as we go 481 */ 482int cachefiles_walk_to_object(struct cachefiles_object *parent, 483 struct cachefiles_object *object, 484 const char *key, 485 struct cachefiles_xattr *auxdata) 486{ 487 struct cachefiles_cache *cache; 488 struct dentry *dir, *next = NULL; 489 struct inode *inode; 490 struct path path; 491 unsigned long start; 492 const char *name; 493 int ret, nlen; 494 495 _enter("OBJ%x{%p},OBJ%x,%s,", 496 parent->fscache.debug_id, parent->dentry, 497 object->fscache.debug_id, key); 498 499 cache = container_of(parent->fscache.cache, 500 struct cachefiles_cache, cache); 501 path.mnt = cache->mnt; 502 503 ASSERT(parent->dentry); 504 ASSERT(d_backing_inode(parent->dentry)); 505 506 if (!(d_is_dir(parent->dentry))) { 507 // TODO: convert file to dir 508 _leave("looking up in none directory"); 509 return -ENOBUFS; 510 } 511 512 dir = dget(parent->dentry); 513 514advance: 515 /* attempt to transit the first directory component */ 516 name = key; 517 nlen = strlen(key); 518 519 /* key ends in a double NUL */ 520 key = key + nlen + 1; 521 if (!*key) 522 key = NULL; 523 524lookup_again: 525 /* search the current directory for the element name */ 526 _debug("lookup '%s'", name); 527 528 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 529 530 start = jiffies; 531 next = lookup_one_len(name, dir, nlen); 532 cachefiles_hist(cachefiles_lookup_histogram, start); 533 if (IS_ERR(next)) { 534 trace_cachefiles_lookup(object, next, NULL); 535 goto lookup_error; 536 } 537 538 inode = d_backing_inode(next); 539 trace_cachefiles_lookup(object, next, inode); 540 _debug("next -> %p %s", next, inode ? "positive" : "negative"); 541 542 if (!key) 543 object->new = !inode; 544 545 /* if this element of the path doesn't exist, then the lookup phase 546 * failed, and we can release any readers in the certain knowledge that 547 * there's nothing for them to actually read */ 548 if (d_is_negative(next)) 549 fscache_object_lookup_negative(&object->fscache); 550 551 /* we need to create the object if it's negative */ 552 if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { 553 /* index objects and intervening tree levels must be subdirs */ 554 if (d_is_negative(next)) { 555 ret = cachefiles_has_space(cache, 1, 0); 556 if (ret < 0) 557 goto no_space_error; 558 559 path.dentry = dir; 560 ret = security_path_mkdir(&path, next, 0); 561 if (ret < 0) 562 goto create_error; 563 start = jiffies; 564 ret = vfs_mkdir(d_inode(dir), next, 0); 565 cachefiles_hist(cachefiles_mkdir_histogram, start); 566 if (!key) 567 trace_cachefiles_mkdir(object, next, ret); 568 if (ret < 0) 569 goto create_error; 570 571 if (unlikely(d_unhashed(next))) { 572 dput(next); 573 inode_unlock(d_inode(dir)); 574 goto lookup_again; 575 } 576 ASSERT(d_backing_inode(next)); 577 578 _debug("mkdir -> %p{%p{ino=%lu}}", 579 next, d_backing_inode(next), d_backing_inode(next)->i_ino); 580 581 } else if (!d_can_lookup(next)) { 582 pr_err("inode %lu is not a directory\n", 583 d_backing_inode(next)->i_ino); 584 ret = -ENOBUFS; 585 goto error; 586 } 587 588 } else { 589 /* non-index objects start out life as files */ 590 if (d_is_negative(next)) { 591 ret = cachefiles_has_space(cache, 1, 0); 592 if (ret < 0) 593 goto no_space_error; 594 595 path.dentry = dir; 596 ret = security_path_mknod(&path, next, S_IFREG, 0); 597 if (ret < 0) 598 goto create_error; 599 start = jiffies; 600 ret = vfs_create(d_inode(dir), next, S_IFREG, true); 601 cachefiles_hist(cachefiles_create_histogram, start); 602 trace_cachefiles_create(object, next, ret); 603 if (ret < 0) 604 goto create_error; 605 606 ASSERT(d_backing_inode(next)); 607 608 _debug("create -> %p{%p{ino=%lu}}", 609 next, d_backing_inode(next), d_backing_inode(next)->i_ino); 610 611 } else if (!d_can_lookup(next) && 612 !d_is_reg(next) 613 ) { 614 pr_err("inode %lu is not a file or directory\n", 615 d_backing_inode(next)->i_ino); 616 ret = -ENOBUFS; 617 goto error; 618 } 619 } 620 621 /* process the next component */ 622 if (key) { 623 _debug("advance"); 624 inode_unlock(d_inode(dir)); 625 dput(dir); 626 dir = next; 627 next = NULL; 628 goto advance; 629 } 630 631 /* we've found the object we were looking for */ 632 object->dentry = next; 633 634 /* if we've found that the terminal object exists, then we need to 635 * check its attributes and delete it if it's out of date */ 636 if (!object->new) { 637 _debug("validate '%pd'", next); 638 639 ret = cachefiles_check_object_xattr(object, auxdata); 640 if (ret == -ESTALE) { 641 /* delete the object (the deleter drops the directory 642 * mutex) */ 643 object->dentry = NULL; 644 645 ret = cachefiles_bury_object(cache, object, dir, next, 646 true, 647 FSCACHE_OBJECT_IS_STALE); 648 dput(next); 649 next = NULL; 650 651 if (ret < 0) 652 goto delete_error; 653 654 _debug("redo lookup"); 655 fscache_object_retrying_stale(&object->fscache); 656 goto lookup_again; 657 } 658 } 659 660 /* note that we're now using this object */ 661 ret = cachefiles_mark_object_active(cache, object); 662 663 inode_unlock(d_inode(dir)); 664 dput(dir); 665 dir = NULL; 666 667 if (ret == -ETIMEDOUT) 668 goto mark_active_timed_out; 669 670 _debug("=== OBTAINED_OBJECT ==="); 671 672 if (object->new) { 673 /* attach data to a newly constructed terminal object */ 674 ret = cachefiles_set_object_xattr(object, auxdata); 675 if (ret < 0) 676 goto check_error; 677 } else { 678 /* always update the atime on an object we've just looked up 679 * (this is used to keep track of culling, and atimes are only 680 * updated by read, write and readdir but not lookup or 681 * open) */ 682 path.dentry = next; 683 touch_atime(&path); 684 } 685 686 /* open a file interface onto a data file */ 687 if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { 688 if (d_is_reg(object->dentry)) { 689 const struct address_space_operations *aops; 690 691 ret = -EPERM; 692 aops = d_backing_inode(object->dentry)->i_mapping->a_ops; 693 if (!aops->bmap) 694 goto check_error; 695 if (object->dentry->d_sb->s_blocksize > PAGE_SIZE) 696 goto check_error; 697 698 object->backer = object->dentry; 699 } else { 700 BUG(); // TODO: open file in data-class subdir 701 } 702 } 703 704 object->new = 0; 705 fscache_obtained_object(&object->fscache); 706 707 _leave(" = 0 [%lu]", d_backing_inode(object->dentry)->i_ino); 708 return 0; 709 710no_space_error: 711 fscache_object_mark_killed(&object->fscache, FSCACHE_OBJECT_NO_SPACE); 712create_error: 713 _debug("create error %d", ret); 714 if (ret == -EIO) 715 cachefiles_io_error(cache, "Create/mkdir failed"); 716 goto error; 717 718mark_active_timed_out: 719 _debug("mark active timed out"); 720 goto release_dentry; 721 722check_error: 723 _debug("check error %d", ret); 724 cachefiles_mark_object_inactive( 725 cache, object, d_backing_inode(object->dentry)->i_blocks); 726release_dentry: 727 dput(object->dentry); 728 object->dentry = NULL; 729 goto error_out; 730 731delete_error: 732 _debug("delete error %d", ret); 733 goto error_out2; 734 735lookup_error: 736 _debug("lookup error %ld", PTR_ERR(next)); 737 ret = PTR_ERR(next); 738 if (ret == -EIO) 739 cachefiles_io_error(cache, "Lookup failed"); 740 next = NULL; 741error: 742 inode_unlock(d_inode(dir)); 743 dput(next); 744error_out2: 745 dput(dir); 746error_out: 747 _leave(" = error %d", -ret); 748 return ret; 749} 750 751/* 752 * get a subdirectory 753 */ 754struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 755 struct dentry *dir, 756 const char *dirname) 757{ 758 struct dentry *subdir; 759 unsigned long start; 760 struct path path; 761 int ret; 762 763 _enter(",,%s", dirname); 764 765 /* search the current directory for the element name */ 766 inode_lock(d_inode(dir)); 767 768retry: 769 start = jiffies; 770 subdir = lookup_one_len(dirname, dir, strlen(dirname)); 771 cachefiles_hist(cachefiles_lookup_histogram, start); 772 if (IS_ERR(subdir)) { 773 if (PTR_ERR(subdir) == -ENOMEM) 774 goto nomem_d_alloc; 775 goto lookup_error; 776 } 777 778 _debug("subdir -> %p %s", 779 subdir, d_backing_inode(subdir) ? "positive" : "negative"); 780 781 /* we need to create the subdir if it doesn't exist yet */ 782 if (d_is_negative(subdir)) { 783 ret = cachefiles_has_space(cache, 1, 0); 784 if (ret < 0) 785 goto mkdir_error; 786 787 _debug("attempt mkdir"); 788 789 path.mnt = cache->mnt; 790 path.dentry = dir; 791 ret = security_path_mkdir(&path, subdir, 0700); 792 if (ret < 0) 793 goto mkdir_error; 794 ret = vfs_mkdir(d_inode(dir), subdir, 0700); 795 if (ret < 0) 796 goto mkdir_error; 797 798 if (unlikely(d_unhashed(subdir))) { 799 dput(subdir); 800 goto retry; 801 } 802 ASSERT(d_backing_inode(subdir)); 803 804 _debug("mkdir -> %p{%p{ino=%lu}}", 805 subdir, 806 d_backing_inode(subdir), 807 d_backing_inode(subdir)->i_ino); 808 } 809 810 inode_unlock(d_inode(dir)); 811 812 /* we need to make sure the subdir is a directory */ 813 ASSERT(d_backing_inode(subdir)); 814 815 if (!d_can_lookup(subdir)) { 816 pr_err("%s is not a directory\n", dirname); 817 ret = -EIO; 818 goto check_error; 819 } 820 821 ret = -EPERM; 822 if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) || 823 !d_backing_inode(subdir)->i_op->lookup || 824 !d_backing_inode(subdir)->i_op->mkdir || 825 !d_backing_inode(subdir)->i_op->create || 826 !d_backing_inode(subdir)->i_op->rename || 827 !d_backing_inode(subdir)->i_op->rmdir || 828 !d_backing_inode(subdir)->i_op->unlink) 829 goto check_error; 830 831 _leave(" = [%lu]", d_backing_inode(subdir)->i_ino); 832 return subdir; 833 834check_error: 835 dput(subdir); 836 _leave(" = %d [check]", ret); 837 return ERR_PTR(ret); 838 839mkdir_error: 840 inode_unlock(d_inode(dir)); 841 dput(subdir); 842 pr_err("mkdir %s failed with error %d\n", dirname, ret); 843 return ERR_PTR(ret); 844 845lookup_error: 846 inode_unlock(d_inode(dir)); 847 ret = PTR_ERR(subdir); 848 pr_err("Lookup %s failed with error %d\n", dirname, ret); 849 return ERR_PTR(ret); 850 851nomem_d_alloc: 852 inode_unlock(d_inode(dir)); 853 _leave(" = -ENOMEM"); 854 return ERR_PTR(-ENOMEM); 855} 856 857/* 858 * find out if an object is in use or not 859 * - if finds object and it's not in use: 860 * - returns a pointer to the object and a reference on it 861 * - returns with the directory locked 862 */ 863static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, 864 struct dentry *dir, 865 char *filename) 866{ 867 struct cachefiles_object *object; 868 struct rb_node *_n; 869 struct dentry *victim; 870 unsigned long start; 871 int ret; 872 873 //_enter(",%pd/,%s", 874 // dir, filename); 875 876 /* look up the victim */ 877 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 878 879 start = jiffies; 880 victim = lookup_one_len(filename, dir, strlen(filename)); 881 cachefiles_hist(cachefiles_lookup_histogram, start); 882 if (IS_ERR(victim)) 883 goto lookup_error; 884 885 //_debug("victim -> %p %s", 886 // victim, d_backing_inode(victim) ? "positive" : "negative"); 887 888 /* if the object is no longer there then we probably retired the object 889 * at the netfs's request whilst the cull was in progress 890 */ 891 if (d_is_negative(victim)) { 892 inode_unlock(d_inode(dir)); 893 dput(victim); 894 _leave(" = -ENOENT [absent]"); 895 return ERR_PTR(-ENOENT); 896 } 897 898 /* check to see if we're using this object */ 899 read_lock(&cache->active_lock); 900 901 _n = cache->active_nodes.rb_node; 902 903 while (_n) { 904 object = rb_entry(_n, struct cachefiles_object, active_node); 905 906 if (object->dentry > victim) 907 _n = _n->rb_left; 908 else if (object->dentry < victim) 909 _n = _n->rb_right; 910 else 911 goto object_in_use; 912 } 913 914 read_unlock(&cache->active_lock); 915 916 //_leave(" = %p", victim); 917 return victim; 918 919object_in_use: 920 read_unlock(&cache->active_lock); 921 inode_unlock(d_inode(dir)); 922 dput(victim); 923 //_leave(" = -EBUSY [in use]"); 924 return ERR_PTR(-EBUSY); 925 926lookup_error: 927 inode_unlock(d_inode(dir)); 928 ret = PTR_ERR(victim); 929 if (ret == -ENOENT) { 930 /* file or dir now absent - probably retired by netfs */ 931 _leave(" = -ESTALE [absent]"); 932 return ERR_PTR(-ESTALE); 933 } 934 935 if (ret == -EIO) { 936 cachefiles_io_error(cache, "Lookup failed"); 937 } else if (ret != -ENOMEM) { 938 pr_err("Internal error: %d\n", ret); 939 ret = -EIO; 940 } 941 942 _leave(" = %d", ret); 943 return ERR_PTR(ret); 944} 945 946/* 947 * cull an object if it's not in use 948 * - called only by cache manager daemon 949 */ 950int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, 951 char *filename) 952{ 953 struct dentry *victim; 954 int ret; 955 956 _enter(",%pd/,%s", dir, filename); 957 958 victim = cachefiles_check_active(cache, dir, filename); 959 if (IS_ERR(victim)) 960 return PTR_ERR(victim); 961 962 _debug("victim -> %p %s", 963 victim, d_backing_inode(victim) ? "positive" : "negative"); 964 965 /* okay... the victim is not being used so we can cull it 966 * - start by marking it as stale 967 */ 968 _debug("victim is cullable"); 969 970 ret = cachefiles_remove_object_xattr(cache, victim); 971 if (ret < 0) 972 goto error_unlock; 973 974 /* actually remove the victim (drops the dir mutex) */ 975 _debug("bury"); 976 977 ret = cachefiles_bury_object(cache, NULL, dir, victim, false, 978 FSCACHE_OBJECT_WAS_CULLED); 979 if (ret < 0) 980 goto error; 981 982 dput(victim); 983 _leave(" = 0"); 984 return 0; 985 986error_unlock: 987 inode_unlock(d_inode(dir)); 988error: 989 dput(victim); 990 if (ret == -ENOENT) { 991 /* file or dir now absent - probably retired by netfs */ 992 _leave(" = -ESTALE [absent]"); 993 return -ESTALE; 994 } 995 996 if (ret != -ENOMEM) { 997 pr_err("Internal error: %d\n", ret); 998 ret = -EIO; 999 } 1000 1001 _leave(" = %d", ret); 1002 return ret; 1003} 1004 1005/* 1006 * find out if an object is in use or not 1007 * - called only by cache manager daemon 1008 * - returns -EBUSY or 0 to indicate whether an object is in use or not 1009 */ 1010int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, 1011 char *filename) 1012{ 1013 struct dentry *victim; 1014 1015 //_enter(",%pd/,%s", 1016 // dir, filename); 1017 1018 victim = cachefiles_check_active(cache, dir, filename); 1019 if (IS_ERR(victim)) 1020 return PTR_ERR(victim); 1021 1022 inode_unlock(d_inode(dir)); 1023 dput(victim); 1024 //_leave(" = 0"); 1025 return 0; 1026} 1027