1 /* 2 * f2fs extent cache support 3 * 4 * Copyright (c) 2015 Motorola Mobility 5 * Copyright (c) 2015 Samsung Electronics 6 * Authors: Jaegeuk Kim <jaegeuk@kernel.org> 7 * Chao Yu <chao2.yu@samsung.com> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/fs.h> 15 #include <linux/f2fs_fs.h> 16 17 #include "f2fs.h" 18 #include "node.h" 19 #include <trace/events/f2fs.h> 20 21 static struct kmem_cache *extent_tree_slab; 22 static struct kmem_cache *extent_node_slab; 23 24 static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi, 25 struct extent_tree *et, struct extent_info *ei, 26 struct rb_node *parent, struct rb_node **p) 27 { 28 struct extent_node *en; 29 30 en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC); 31 if (!en) 32 return NULL; 33 34 en->ei = *ei; 35 INIT_LIST_HEAD(&en->list); 36 en->et = et; 37 38 rb_link_node(&en->rb_node, parent, p); 39 rb_insert_color(&en->rb_node, &et->root); 40 atomic_inc(&et->node_cnt); 41 atomic_inc(&sbi->total_ext_node); 42 return en; 43 } 44 45 static void __detach_extent_node(struct f2fs_sb_info *sbi, 46 struct extent_tree *et, struct extent_node *en) 47 { 48 rb_erase(&en->rb_node, &et->root); 49 atomic_dec(&et->node_cnt); 50 atomic_dec(&sbi->total_ext_node); 51 52 if (et->cached_en == en) 53 et->cached_en = NULL; 54 kmem_cache_free(extent_node_slab, en); 55 } 56 57 /* 58 * Flow to release an extent_node: 59 * 1. list_del_init 60 * 2. __detach_extent_node 61 * 3. kmem_cache_free. 62 */ 63 static void __release_extent_node(struct f2fs_sb_info *sbi, 64 struct extent_tree *et, struct extent_node *en) 65 { 66 spin_lock(&sbi->extent_lock); 67 f2fs_bug_on(sbi, list_empty(&en->list)); 68 list_del_init(&en->list); 69 spin_unlock(&sbi->extent_lock); 70 71 __detach_extent_node(sbi, et, en); 72 } 73 74 static struct extent_tree *__grab_extent_tree(struct inode *inode) 75 { 76 struct f2fs_sb_info *sbi = F2FS_I_SB(inode); 77 struct extent_tree *et; 78 nid_t ino = inode->i_ino; 79 80 down_write(&sbi->extent_tree_lock); 81 et = radix_tree_lookup(&sbi->extent_tree_root, ino); 82 if (!et) { 83 et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS); 84 f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et); 85 memset(et, 0, sizeof(struct extent_tree)); 86 et->ino = ino; 87 et->root = RB_ROOT; 88 et->cached_en = NULL; 89 rwlock_init(&et->lock); 90 INIT_LIST_HEAD(&et->list); 91 atomic_set(&et->node_cnt, 0); 92 atomic_inc(&sbi->total_ext_tree); 93 } else { 94 atomic_dec(&sbi->total_zombie_tree); 95 list_del_init(&et->list); 96 } 97 up_write(&sbi->extent_tree_lock); 98 99 /* never died until evict_inode */ 100 F2FS_I(inode)->extent_tree = et; 101 102 return et; 103 } 104 105 static struct extent_node *__lookup_extent_tree(struct f2fs_sb_info *sbi, 106 struct extent_tree *et, unsigned int fofs) 107 { 108 struct rb_node *node = et->root.rb_node; 109 struct extent_node *en = et->cached_en; 110 111 if (en) { 112 struct extent_info *cei = &en->ei; 113 114 if (cei->fofs <= fofs && cei->fofs + cei->len > fofs) { 115 stat_inc_cached_node_hit(sbi); 116 return en; 117 } 118 } 119 120 while (node) { 121 en = rb_entry(node, struct extent_node, rb_node); 122 123 if (fofs < en->ei.fofs) { 124 node = node->rb_left; 125 } else if (fofs >= en->ei.fofs + en->ei.len) { 126 node = node->rb_right; 127 } else { 128 stat_inc_rbtree_node_hit(sbi); 129 return en; 130 } 131 } 132 return NULL; 133 } 134 135 static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi, 136 struct extent_tree *et, struct extent_info *ei) 137 { 138 struct rb_node **p = &et->root.rb_node; 139 struct extent_node *en; 140 141 en = __attach_extent_node(sbi, et, ei, NULL, p); 142 if (!en) 143 return NULL; 144 145 et->largest = en->ei; 146 et->cached_en = en; 147 return en; 148 } 149 150 static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, 151 struct extent_tree *et) 152 { 153 struct rb_node *node, *next; 154 struct extent_node *en; 155 unsigned int count = atomic_read(&et->node_cnt); 156 157 node = rb_first(&et->root); 158 while (node) { 159 next = rb_next(node); 160 en = rb_entry(node, struct extent_node, rb_node); 161 __release_extent_node(sbi, et, en); 162 node = next; 163 } 164 165 return count - atomic_read(&et->node_cnt); 166 } 167 168 static void __drop_largest_extent(struct inode *inode, 169 pgoff_t fofs, unsigned int len) 170 { 171 struct extent_info *largest = &F2FS_I(inode)->extent_tree->largest; 172 173 if (fofs < largest->fofs + largest->len && fofs + len > largest->fofs) 174 largest->len = 0; 175 } 176 177 /* return true, if inode page is changed */ 178 bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext) 179 { 180 struct f2fs_sb_info *sbi = F2FS_I_SB(inode); 181 struct extent_tree *et; 182 struct extent_node *en; 183 struct extent_info ei; 184 185 if (!f2fs_may_extent_tree(inode)) { 186 /* drop largest extent */ 187 if (i_ext && i_ext->len) { 188 i_ext->len = 0; 189 return true; 190 } 191 return false; 192 } 193 194 et = __grab_extent_tree(inode); 195 196 if (!i_ext || !i_ext->len) 197 return false; 198 199 set_extent_info(&ei, le32_to_cpu(i_ext->fofs), 200 le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len)); 201 202 write_lock(&et->lock); 203 if (atomic_read(&et->node_cnt)) 204 goto out; 205 206 en = __init_extent_tree(sbi, et, &ei); 207 if (en) { 208 spin_lock(&sbi->extent_lock); 209 list_add_tail(&en->list, &sbi->extent_list); 210 spin_unlock(&sbi->extent_lock); 211 } 212 out: 213 write_unlock(&et->lock); 214 return false; 215 } 216 217 static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs, 218 struct extent_info *ei) 219 { 220 struct f2fs_sb_info *sbi = F2FS_I_SB(inode); 221 struct extent_tree *et = F2FS_I(inode)->extent_tree; 222 struct extent_node *en; 223 bool ret = false; 224 225 f2fs_bug_on(sbi, !et); 226 227 trace_f2fs_lookup_extent_tree_start(inode, pgofs); 228 229 read_lock(&et->lock); 230 231 if (et->largest.fofs <= pgofs && 232 et->largest.fofs + et->largest.len > pgofs) { 233 *ei = et->largest; 234 ret = true; 235 stat_inc_largest_node_hit(sbi); 236 goto out; 237 } 238 239 en = __lookup_extent_tree(sbi, et, pgofs); 240 if (en) { 241 *ei = en->ei; 242 spin_lock(&sbi->extent_lock); 243 if (!list_empty(&en->list)) { 244 list_move_tail(&en->list, &sbi->extent_list); 245 et->cached_en = en; 246 } 247 spin_unlock(&sbi->extent_lock); 248 ret = true; 249 } 250 out: 251 stat_inc_total_hit(sbi); 252 read_unlock(&et->lock); 253 254 trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei); 255 return ret; 256 } 257 258 259 /* 260 * lookup extent at @fofs, if hit, return the extent 261 * if not, return NULL and 262 * @prev_ex: extent before fofs 263 * @next_ex: extent after fofs 264 * @insert_p: insert point for new extent at fofs 265 * in order to simpfy the insertion after. 266 * tree must stay unchanged between lookup and insertion. 267 */ 268 static struct extent_node *__lookup_extent_tree_ret(struct extent_tree *et, 269 unsigned int fofs, 270 struct extent_node **prev_ex, 271 struct extent_node **next_ex, 272 struct rb_node ***insert_p, 273 struct rb_node **insert_parent) 274 { 275 struct rb_node **pnode = &et->root.rb_node; 276 struct rb_node *parent = NULL, *tmp_node; 277 struct extent_node *en = et->cached_en; 278 279 *insert_p = NULL; 280 *insert_parent = NULL; 281 *prev_ex = NULL; 282 *next_ex = NULL; 283 284 if (RB_EMPTY_ROOT(&et->root)) 285 return NULL; 286 287 if (en) { 288 struct extent_info *cei = &en->ei; 289 290 if (cei->fofs <= fofs && cei->fofs + cei->len > fofs) 291 goto lookup_neighbors; 292 } 293 294 while (*pnode) { 295 parent = *pnode; 296 en = rb_entry(*pnode, struct extent_node, rb_node); 297 298 if (fofs < en->ei.fofs) 299 pnode = &(*pnode)->rb_left; 300 else if (fofs >= en->ei.fofs + en->ei.len) 301 pnode = &(*pnode)->rb_right; 302 else 303 goto lookup_neighbors; 304 } 305 306 *insert_p = pnode; 307 *insert_parent = parent; 308 309 en = rb_entry(parent, struct extent_node, rb_node); 310 tmp_node = parent; 311 if (parent && fofs > en->ei.fofs) 312 tmp_node = rb_next(parent); 313 *next_ex = tmp_node ? 314 rb_entry(tmp_node, struct extent_node, rb_node) : NULL; 315 316 tmp_node = parent; 317 if (parent && fofs < en->ei.fofs) 318 tmp_node = rb_prev(parent); 319 *prev_ex = tmp_node ? 320 rb_entry(tmp_node, struct extent_node, rb_node) : NULL; 321 return NULL; 322 323 lookup_neighbors: 324 if (fofs == en->ei.fofs) { 325 /* lookup prev node for merging backward later */ 326 tmp_node = rb_prev(&en->rb_node); 327 *prev_ex = tmp_node ? 328 rb_entry(tmp_node, struct extent_node, rb_node) : NULL; 329 } 330 if (fofs == en->ei.fofs + en->ei.len - 1) { 331 /* lookup next node for merging frontward later */ 332 tmp_node = rb_next(&en->rb_node); 333 *next_ex = tmp_node ? 334 rb_entry(tmp_node, struct extent_node, rb_node) : NULL; 335 } 336 return en; 337 } 338 339 static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi, 340 struct extent_tree *et, struct extent_info *ei, 341 struct extent_node *prev_ex, 342 struct extent_node *next_ex) 343 { 344 struct extent_node *en = NULL; 345 346 if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) { 347 prev_ex->ei.len += ei->len; 348 ei = &prev_ex->ei; 349 en = prev_ex; 350 } 351 352 if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) { 353 if (en) 354 __release_extent_node(sbi, et, prev_ex); 355 next_ex->ei.fofs = ei->fofs; 356 next_ex->ei.blk = ei->blk; 357 next_ex->ei.len += ei->len; 358 en = next_ex; 359 } 360 361 if (!en) 362 return NULL; 363 364 __try_update_largest_extent(et, en); 365 366 spin_lock(&sbi->extent_lock); 367 if (!list_empty(&en->list)) { 368 list_move_tail(&en->list, &sbi->extent_list); 369 et->cached_en = en; 370 } 371 spin_unlock(&sbi->extent_lock); 372 return en; 373 } 374 375 static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi, 376 struct extent_tree *et, struct extent_info *ei, 377 struct rb_node **insert_p, 378 struct rb_node *insert_parent) 379 { 380 struct rb_node **p = &et->root.rb_node; 381 struct rb_node *parent = NULL; 382 struct extent_node *en = NULL; 383 384 if (insert_p && insert_parent) { 385 parent = insert_parent; 386 p = insert_p; 387 goto do_insert; 388 } 389 390 while (*p) { 391 parent = *p; 392 en = rb_entry(parent, struct extent_node, rb_node); 393 394 if (ei->fofs < en->ei.fofs) 395 p = &(*p)->rb_left; 396 else if (ei->fofs >= en->ei.fofs + en->ei.len) 397 p = &(*p)->rb_right; 398 else 399 f2fs_bug_on(sbi, 1); 400 } 401 do_insert: 402 en = __attach_extent_node(sbi, et, ei, parent, p); 403 if (!en) 404 return NULL; 405 406 __try_update_largest_extent(et, en); 407 408 /* update in global extent list */ 409 spin_lock(&sbi->extent_lock); 410 list_add_tail(&en->list, &sbi->extent_list); 411 et->cached_en = en; 412 spin_unlock(&sbi->extent_lock); 413 return en; 414 } 415 416 static unsigned int f2fs_update_extent_tree_range(struct inode *inode, 417 pgoff_t fofs, block_t blkaddr, unsigned int len) 418 { 419 struct f2fs_sb_info *sbi = F2FS_I_SB(inode); 420 struct extent_tree *et = F2FS_I(inode)->extent_tree; 421 struct extent_node *en = NULL, *en1 = NULL; 422 struct extent_node *prev_en = NULL, *next_en = NULL; 423 struct extent_info ei, dei, prev; 424 struct rb_node **insert_p = NULL, *insert_parent = NULL; 425 unsigned int end = fofs + len; 426 unsigned int pos = (unsigned int)fofs; 427 428 if (!et) 429 return false; 430 431 trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, len); 432 433 write_lock(&et->lock); 434 435 if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) { 436 write_unlock(&et->lock); 437 return false; 438 } 439 440 prev = et->largest; 441 dei.len = 0; 442 443 /* 444 * drop largest extent before lookup, in case it's already 445 * been shrunk from extent tree 446 */ 447 __drop_largest_extent(inode, fofs, len); 448 449 /* 1. lookup first extent node in range [fofs, fofs + len - 1] */ 450 en = __lookup_extent_tree_ret(et, fofs, &prev_en, &next_en, 451 &insert_p, &insert_parent); 452 if (!en) 453 en = next_en; 454 455 /* 2. invlidate all extent nodes in range [fofs, fofs + len - 1] */ 456 while (en && en->ei.fofs < end) { 457 unsigned int org_end; 458 int parts = 0; /* # of parts current extent split into */ 459 460 next_en = en1 = NULL; 461 462 dei = en->ei; 463 org_end = dei.fofs + dei.len; 464 f2fs_bug_on(sbi, pos >= org_end); 465 466 if (pos > dei.fofs && pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) { 467 en->ei.len = pos - en->ei.fofs; 468 prev_en = en; 469 parts = 1; 470 } 471 472 if (end < org_end && org_end - end >= F2FS_MIN_EXTENT_LEN) { 473 if (parts) { 474 set_extent_info(&ei, end, 475 end - dei.fofs + dei.blk, 476 org_end - end); 477 en1 = __insert_extent_tree(sbi, et, &ei, 478 NULL, NULL); 479 next_en = en1; 480 } else { 481 en->ei.fofs = end; 482 en->ei.blk += end - dei.fofs; 483 en->ei.len -= end - dei.fofs; 484 next_en = en; 485 } 486 parts++; 487 } 488 489 if (!next_en) { 490 struct rb_node *node = rb_next(&en->rb_node); 491 492 next_en = node ? 493 rb_entry(node, struct extent_node, rb_node) 494 : NULL; 495 } 496 497 if (parts) 498 __try_update_largest_extent(et, en); 499 else 500 __release_extent_node(sbi, et, en); 501 502 /* 503 * if original extent is split into zero or two parts, extent 504 * tree has been altered by deletion or insertion, therefore 505 * invalidate pointers regard to tree. 506 */ 507 if (parts != 1) { 508 insert_p = NULL; 509 insert_parent = NULL; 510 } 511 en = next_en; 512 } 513 514 /* 3. update extent in extent cache */ 515 if (blkaddr) { 516 517 set_extent_info(&ei, fofs, blkaddr, len); 518 if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en)) 519 __insert_extent_tree(sbi, et, &ei, 520 insert_p, insert_parent); 521 522 /* give up extent_cache, if split and small updates happen */ 523 if (dei.len >= 1 && 524 prev.len < F2FS_MIN_EXTENT_LEN && 525 et->largest.len < F2FS_MIN_EXTENT_LEN) { 526 et->largest.len = 0; 527 set_inode_flag(F2FS_I(inode), FI_NO_EXTENT); 528 } 529 } 530 531 if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) 532 __free_extent_tree(sbi, et); 533 534 write_unlock(&et->lock); 535 536 return !__is_extent_same(&prev, &et->largest); 537 } 538 539 unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) 540 { 541 struct extent_tree *et, *next; 542 struct extent_node *en; 543 unsigned int node_cnt = 0, tree_cnt = 0; 544 int remained; 545 546 if (!test_opt(sbi, EXTENT_CACHE)) 547 return 0; 548 549 if (!atomic_read(&sbi->total_zombie_tree)) 550 goto free_node; 551 552 if (!down_write_trylock(&sbi->extent_tree_lock)) 553 goto out; 554 555 /* 1. remove unreferenced extent tree */ 556 list_for_each_entry_safe(et, next, &sbi->zombie_list, list) { 557 if (atomic_read(&et->node_cnt)) { 558 write_lock(&et->lock); 559 node_cnt += __free_extent_tree(sbi, et); 560 write_unlock(&et->lock); 561 } 562 f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); 563 list_del_init(&et->list); 564 radix_tree_delete(&sbi->extent_tree_root, et->ino); 565 kmem_cache_free(extent_tree_slab, et); 566 atomic_dec(&sbi->total_ext_tree); 567 atomic_dec(&sbi->total_zombie_tree); 568 tree_cnt++; 569 570 if (node_cnt + tree_cnt >= nr_shrink) 571 goto unlock_out; 572 cond_resched(); 573 } 574 up_write(&sbi->extent_tree_lock); 575 576 free_node: 577 /* 2. remove LRU extent entries */ 578 if (!down_write_trylock(&sbi->extent_tree_lock)) 579 goto out; 580 581 remained = nr_shrink - (node_cnt + tree_cnt); 582 583 spin_lock(&sbi->extent_lock); 584 for (; remained > 0; remained--) { 585 if (list_empty(&sbi->extent_list)) 586 break; 587 en = list_first_entry(&sbi->extent_list, 588 struct extent_node, list); 589 et = en->et; 590 if (!write_trylock(&et->lock)) { 591 /* refresh this extent node's position in extent list */ 592 list_move_tail(&en->list, &sbi->extent_list); 593 continue; 594 } 595 596 list_del_init(&en->list); 597 spin_unlock(&sbi->extent_lock); 598 599 __detach_extent_node(sbi, et, en); 600 601 write_unlock(&et->lock); 602 node_cnt++; 603 spin_lock(&sbi->extent_lock); 604 } 605 spin_unlock(&sbi->extent_lock); 606 607 unlock_out: 608 up_write(&sbi->extent_tree_lock); 609 out: 610 trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt); 611 612 return node_cnt + tree_cnt; 613 } 614 615 unsigned int f2fs_destroy_extent_node(struct inode *inode) 616 { 617 struct f2fs_sb_info *sbi = F2FS_I_SB(inode); 618 struct extent_tree *et = F2FS_I(inode)->extent_tree; 619 unsigned int node_cnt = 0; 620 621 if (!et || !atomic_read(&et->node_cnt)) 622 return 0; 623 624 write_lock(&et->lock); 625 node_cnt = __free_extent_tree(sbi, et); 626 write_unlock(&et->lock); 627 628 return node_cnt; 629 } 630 631 void f2fs_destroy_extent_tree(struct inode *inode) 632 { 633 struct f2fs_sb_info *sbi = F2FS_I_SB(inode); 634 struct extent_tree *et = F2FS_I(inode)->extent_tree; 635 unsigned int node_cnt = 0; 636 637 if (!et) 638 return; 639 640 if (inode->i_nlink && !is_bad_inode(inode) && 641 atomic_read(&et->node_cnt)) { 642 down_write(&sbi->extent_tree_lock); 643 list_add_tail(&et->list, &sbi->zombie_list); 644 atomic_inc(&sbi->total_zombie_tree); 645 up_write(&sbi->extent_tree_lock); 646 return; 647 } 648 649 /* free all extent info belong to this extent tree */ 650 node_cnt = f2fs_destroy_extent_node(inode); 651 652 /* delete extent tree entry in radix tree */ 653 down_write(&sbi->extent_tree_lock); 654 f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); 655 radix_tree_delete(&sbi->extent_tree_root, inode->i_ino); 656 kmem_cache_free(extent_tree_slab, et); 657 atomic_dec(&sbi->total_ext_tree); 658 up_write(&sbi->extent_tree_lock); 659 660 F2FS_I(inode)->extent_tree = NULL; 661 662 trace_f2fs_destroy_extent_tree(inode, node_cnt); 663 } 664 665 bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs, 666 struct extent_info *ei) 667 { 668 if (!f2fs_may_extent_tree(inode)) 669 return false; 670 671 return f2fs_lookup_extent_tree(inode, pgofs, ei); 672 } 673 674 void f2fs_update_extent_cache(struct dnode_of_data *dn) 675 { 676 pgoff_t fofs; 677 block_t blkaddr; 678 679 if (!f2fs_may_extent_tree(dn->inode)) 680 return; 681 682 if (dn->data_blkaddr == NEW_ADDR) 683 blkaddr = NULL_ADDR; 684 else 685 blkaddr = dn->data_blkaddr; 686 687 fofs = start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) + 688 dn->ofs_in_node; 689 690 if (f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, 1)) 691 sync_inode_page(dn); 692 } 693 694 void f2fs_update_extent_cache_range(struct dnode_of_data *dn, 695 pgoff_t fofs, block_t blkaddr, unsigned int len) 696 697 { 698 if (!f2fs_may_extent_tree(dn->inode)) 699 return; 700 701 if (f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, len)) 702 sync_inode_page(dn); 703 } 704 705 void init_extent_cache_info(struct f2fs_sb_info *sbi) 706 { 707 INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO); 708 init_rwsem(&sbi->extent_tree_lock); 709 INIT_LIST_HEAD(&sbi->extent_list); 710 spin_lock_init(&sbi->extent_lock); 711 atomic_set(&sbi->total_ext_tree, 0); 712 INIT_LIST_HEAD(&sbi->zombie_list); 713 atomic_set(&sbi->total_zombie_tree, 0); 714 atomic_set(&sbi->total_ext_node, 0); 715 } 716 717 int __init create_extent_cache(void) 718 { 719 extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree", 720 sizeof(struct extent_tree)); 721 if (!extent_tree_slab) 722 return -ENOMEM; 723 extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node", 724 sizeof(struct extent_node)); 725 if (!extent_node_slab) { 726 kmem_cache_destroy(extent_tree_slab); 727 return -ENOMEM; 728 } 729 return 0; 730 } 731 732 void destroy_extent_cache(void) 733 { 734 kmem_cache_destroy(extent_node_slab); 735 kmem_cache_destroy(extent_tree_slab); 736 } 737