root/fs/f2fs/extent_cache.c

DEFINITIONS

1. __lookup_rb_tree_fast
2. __lookup_rb_tree_slow
3. f2fs_lookup_rb_tree
4. f2fs_lookup_rb_tree_for_insert
5. f2fs_lookup_rb_tree_ret
6. f2fs_check_rb_tree_consistence
7. __attach_extent_node
8. __detach_extent_node
9. __release_extent_node
10. __grab_extent_tree
11. __init_extent_tree
12. __free_extent_tree
13. __drop_largest_extent
14. __f2fs_init_extent_tree
15. f2fs_init_extent_tree
16. f2fs_lookup_extent_tree
17. __try_merge_extent_node
18. __insert_extent_tree
19. f2fs_update_extent_tree_range
20. f2fs_shrink_extent_tree
21. f2fs_destroy_extent_node
22. f2fs_drop_extent_tree
23. f2fs_destroy_extent_tree
24. f2fs_lookup_extent_cache
25. f2fs_update_extent_cache
26. f2fs_update_extent_cache_range
27. f2fs_init_extent_cache_info
28. f2fs_create_extent_cache
29. f2fs_destroy_extent_cache

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * f2fs extent cache support
   4  *
   5  * Copyright (c) 2015 Motorola Mobility
   6  * Copyright (c) 2015 Samsung Electronics
   7  * Authors: Jaegeuk Kim <jaegeuk@kernel.org>
   8  *          Chao Yu <chao2.yu@samsung.com>
   9  */
  10 
  11 #include <linux/fs.h>
  12 #include <linux/f2fs_fs.h>
  13 
  14 #include "f2fs.h"
  15 #include "node.h"
  16 #include <trace/events/f2fs.h>
  17 
  18 static struct rb_entry *__lookup_rb_tree_fast(struct rb_entry *cached_re,
  19                                                         unsigned int ofs)
  20 {
  21         if (cached_re) {
  22                 if (cached_re->ofs <= ofs &&
  23                                 cached_re->ofs + cached_re->len > ofs) {
  24                         return cached_re;
  25                 }
  26         }
  27         return NULL;
  28 }
  29 
  30 static struct rb_entry *__lookup_rb_tree_slow(struct rb_root_cached *root,
  31                                                         unsigned int ofs)
  32 {
  33         struct rb_node *node = root->rb_root.rb_node;
  34         struct rb_entry *re;
  35 
  36         while (node) {
  37                 re = rb_entry(node, struct rb_entry, rb_node);
  38 
  39                 if (ofs < re->ofs)
  40                         node = node->rb_left;
  41                 else if (ofs >= re->ofs + re->len)
  42                         node = node->rb_right;
  43                 else
  44                         return re;
  45         }
  46         return NULL;
  47 }
  48 
  49 struct rb_entry *f2fs_lookup_rb_tree(struct rb_root_cached *root,
  50                                 struct rb_entry *cached_re, unsigned int ofs)
  51 {
  52         struct rb_entry *re;
  53 
  54         re = __lookup_rb_tree_fast(cached_re, ofs);
  55         if (!re)
  56                 return __lookup_rb_tree_slow(root, ofs);
  57 
  58         return re;
  59 }
  60 
  61 struct rb_node **f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi,
  62                                 struct rb_root_cached *root,
  63                                 struct rb_node **parent,
  64                                 unsigned int ofs, bool *leftmost)
  65 {
  66         struct rb_node **p = &root->rb_root.rb_node;
  67         struct rb_entry *re;
  68 
  69         while (*p) {
  70                 *parent = *p;
  71                 re = rb_entry(*parent, struct rb_entry, rb_node);
  72 
  73                 if (ofs < re->ofs) {
  74                         p = &(*p)->rb_left;
  75                 } else if (ofs >= re->ofs + re->len) {
  76                         p = &(*p)->rb_right;
  77                         *leftmost = false;
  78                 } else {
  79                         f2fs_bug_on(sbi, 1);
  80                 }
  81         }
  82 
  83         return p;
  84 }
  85 
  86 /*
  87  * lookup rb entry in position of @ofs in rb-tree,
  88  * if hit, return the entry, otherwise, return NULL
  89  * @prev_ex: extent before ofs
  90  * @next_ex: extent after ofs
  91  * @insert_p: insert point for new extent at ofs
  92  * in order to simpfy the insertion after.
  93  * tree must stay unchanged between lookup and insertion.
  94  */
  95 struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
  96                                 struct rb_entry *cached_re,
  97                                 unsigned int ofs,
  98                                 struct rb_entry **prev_entry,
  99                                 struct rb_entry **next_entry,
 100                                 struct rb_node ***insert_p,
 101                                 struct rb_node **insert_parent,
 102                                 bool force, bool *leftmost)
 103 {
 104         struct rb_node **pnode = &root->rb_root.rb_node;
 105         struct rb_node *parent = NULL, *tmp_node;
 106         struct rb_entry *re = cached_re;
 107 
 108         *insert_p = NULL;
 109         *insert_parent = NULL;
 110         *prev_entry = NULL;
 111         *next_entry = NULL;
 112 
 113         if (RB_EMPTY_ROOT(&root->rb_root))
 114                 return NULL;
 115 
 116         if (re) {
 117                 if (re->ofs <= ofs && re->ofs + re->len > ofs)
 118                         goto lookup_neighbors;
 119         }
 120 
 121         if (leftmost)
 122                 *leftmost = true;
 123 
 124         while (*pnode) {
 125                 parent = *pnode;
 126                 re = rb_entry(*pnode, struct rb_entry, rb_node);
 127 
 128                 if (ofs < re->ofs) {
 129                         pnode = &(*pnode)->rb_left;
 130                 } else if (ofs >= re->ofs + re->len) {
 131                         pnode = &(*pnode)->rb_right;
 132                         if (leftmost)
 133                                 *leftmost = false;
 134                 } else {
 135                         goto lookup_neighbors;
 136                 }
 137         }
 138 
 139         *insert_p = pnode;
 140         *insert_parent = parent;
 141 
 142         re = rb_entry(parent, struct rb_entry, rb_node);
 143         tmp_node = parent;
 144         if (parent && ofs > re->ofs)
 145                 tmp_node = rb_next(parent);
 146         *next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
 147 
 148         tmp_node = parent;
 149         if (parent && ofs < re->ofs)
 150                 tmp_node = rb_prev(parent);
 151         *prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
 152         return NULL;
 153 
 154 lookup_neighbors:
 155         if (ofs == re->ofs || force) {
 156                 /* lookup prev node for merging backward later */
 157                 tmp_node = rb_prev(&re->rb_node);
 158                 *prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
 159         }
 160         if (ofs == re->ofs + re->len - 1 || force) {
 161                 /* lookup next node for merging frontward later */
 162                 tmp_node = rb_next(&re->rb_node);
 163                 *next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
 164         }
 165         return re;
 166 }
 167 
 168 bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
 169                                                 struct rb_root_cached *root)
 170 {
 171 #ifdef CONFIG_F2FS_CHECK_FS
 172         struct rb_node *cur = rb_first_cached(root), *next;
 173         struct rb_entry *cur_re, *next_re;
 174 
 175         if (!cur)
 176                 return true;
 177 
 178         while (cur) {
 179                 next = rb_next(cur);
 180                 if (!next)
 181                         return true;
 182 
 183                 cur_re = rb_entry(cur, struct rb_entry, rb_node);
 184                 next_re = rb_entry(next, struct rb_entry, rb_node);
 185 
 186                 if (cur_re->ofs + cur_re->len > next_re->ofs) {
 187                         f2fs_info(sbi, "inconsistent rbtree, cur(%u, %u) next(%u, %u)",
 188                                   cur_re->ofs, cur_re->len,
 189                                   next_re->ofs, next_re->len);
 190                         return false;
 191                 }
 192 
 193                 cur = next;
 194         }
 195 #endif
 196         return true;
 197 }
 198 
 199 static struct kmem_cache *extent_tree_slab;
 200 static struct kmem_cache *extent_node_slab;
 201 
 202 static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
 203                                 struct extent_tree *et, struct extent_info *ei,
 204                                 struct rb_node *parent, struct rb_node **p,
 205                                 bool leftmost)
 206 {
 207         struct extent_node *en;
 208 
 209         en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC);
 210         if (!en)
 211                 return NULL;
 212 
 213         en->ei = *ei;
 214         INIT_LIST_HEAD(&en->list);
 215         en->et = et;
 216 
 217         rb_link_node(&en->rb_node, parent, p);
 218         rb_insert_color_cached(&en->rb_node, &et->root, leftmost);
 219         atomic_inc(&et->node_cnt);
 220         atomic_inc(&sbi->total_ext_node);
 221         return en;
 222 }
 223 
 224 static void __detach_extent_node(struct f2fs_sb_info *sbi,
 225                                 struct extent_tree *et, struct extent_node *en)
 226 {
 227         rb_erase_cached(&en->rb_node, &et->root);
 228         atomic_dec(&et->node_cnt);
 229         atomic_dec(&sbi->total_ext_node);
 230 
 231         if (et->cached_en == en)
 232                 et->cached_en = NULL;
 233         kmem_cache_free(extent_node_slab, en);
 234 }
 235 
 236 /*
 237  * Flow to release an extent_node:
 238  * 1. list_del_init
 239  * 2. __detach_extent_node
 240  * 3. kmem_cache_free.
 241  */
 242 static void __release_extent_node(struct f2fs_sb_info *sbi,
 243                         struct extent_tree *et, struct extent_node *en)
 244 {
 245         spin_lock(&sbi->extent_lock);
 246         f2fs_bug_on(sbi, list_empty(&en->list));
 247         list_del_init(&en->list);
 248         spin_unlock(&sbi->extent_lock);
 249 
 250         __detach_extent_node(sbi, et, en);
 251 }
 252 
 253 static struct extent_tree *__grab_extent_tree(struct inode *inode)
 254 {
 255         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 256         struct extent_tree *et;
 257         nid_t ino = inode->i_ino;
 258 
 259         mutex_lock(&sbi->extent_tree_lock);
 260         et = radix_tree_lookup(&sbi->extent_tree_root, ino);
 261         if (!et) {
 262                 et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS);
 263                 f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et);
 264                 memset(et, 0, sizeof(struct extent_tree));
 265                 et->ino = ino;
 266                 et->root = RB_ROOT_CACHED;
 267                 et->cached_en = NULL;
 268                 rwlock_init(&et->lock);
 269                 INIT_LIST_HEAD(&et->list);
 270                 atomic_set(&et->node_cnt, 0);
 271                 atomic_inc(&sbi->total_ext_tree);
 272         } else {
 273                 atomic_dec(&sbi->total_zombie_tree);
 274                 list_del_init(&et->list);
 275         }
 276         mutex_unlock(&sbi->extent_tree_lock);
 277 
 278         /* never died until evict_inode */
 279         F2FS_I(inode)->extent_tree = et;
 280 
 281         return et;
 282 }
 283 
 284 static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi,
 285                                 struct extent_tree *et, struct extent_info *ei)
 286 {
 287         struct rb_node **p = &et->root.rb_root.rb_node;
 288         struct extent_node *en;
 289 
 290         en = __attach_extent_node(sbi, et, ei, NULL, p, true);
 291         if (!en)
 292                 return NULL;
 293 
 294         et->largest = en->ei;
 295         et->cached_en = en;
 296         return en;
 297 }
 298 
 299 static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
 300                                         struct extent_tree *et)
 301 {
 302         struct rb_node *node, *next;
 303         struct extent_node *en;
 304         unsigned int count = atomic_read(&et->node_cnt);
 305 
 306         node = rb_first_cached(&et->root);
 307         while (node) {
 308                 next = rb_next(node);
 309                 en = rb_entry(node, struct extent_node, rb_node);
 310                 __release_extent_node(sbi, et, en);
 311                 node = next;
 312         }
 313 
 314         return count - atomic_read(&et->node_cnt);
 315 }
 316 
 317 static void __drop_largest_extent(struct extent_tree *et,
 318                                         pgoff_t fofs, unsigned int len)
 319 {
 320         if (fofs < et->largest.fofs + et->largest.len &&
 321                         fofs + len > et->largest.fofs) {
 322                 et->largest.len = 0;
 323                 et->largest_updated = true;
 324         }
 325 }
 326 
 327 /* return true, if inode page is changed */
 328 static bool __f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
 329 {
 330         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 331         struct extent_tree *et;
 332         struct extent_node *en;
 333         struct extent_info ei;
 334 
 335         if (!f2fs_may_extent_tree(inode)) {
 336                 /* drop largest extent */
 337                 if (i_ext && i_ext->len) {
 338                         i_ext->len = 0;
 339                         return true;
 340                 }
 341                 return false;
 342         }
 343 
 344         et = __grab_extent_tree(inode);
 345 
 346         if (!i_ext || !i_ext->len)
 347                 return false;
 348 
 349         get_extent_info(&ei, i_ext);
 350 
 351         write_lock(&et->lock);
 352         if (atomic_read(&et->node_cnt))
 353                 goto out;
 354 
 355         en = __init_extent_tree(sbi, et, &ei);
 356         if (en) {
 357                 spin_lock(&sbi->extent_lock);
 358                 list_add_tail(&en->list, &sbi->extent_list);
 359                 spin_unlock(&sbi->extent_lock);
 360         }
 361 out:
 362         write_unlock(&et->lock);
 363         return false;
 364 }
 365 
 366 bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
 367 {
 368         bool ret =  __f2fs_init_extent_tree(inode, i_ext);
 369 
 370         if (!F2FS_I(inode)->extent_tree)
 371                 set_inode_flag(inode, FI_NO_EXTENT);
 372 
 373         return ret;
 374 }
 375 
 376 static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 377                                                         struct extent_info *ei)
 378 {
 379         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 380         struct extent_tree *et = F2FS_I(inode)->extent_tree;
 381         struct extent_node *en;
 382         bool ret = false;
 383 
 384         f2fs_bug_on(sbi, !et);
 385 
 386         trace_f2fs_lookup_extent_tree_start(inode, pgofs);
 387 
 388         read_lock(&et->lock);
 389 
 390         if (et->largest.fofs <= pgofs &&
 391                         et->largest.fofs + et->largest.len > pgofs) {
 392                 *ei = et->largest;
 393                 ret = true;
 394                 stat_inc_largest_node_hit(sbi);
 395                 goto out;
 396         }
 397 
 398         en = (struct extent_node *)f2fs_lookup_rb_tree(&et->root,
 399                                 (struct rb_entry *)et->cached_en, pgofs);
 400         if (!en)
 401                 goto out;
 402 
 403         if (en == et->cached_en)
 404                 stat_inc_cached_node_hit(sbi);
 405         else
 406                 stat_inc_rbtree_node_hit(sbi);
 407 
 408         *ei = en->ei;
 409         spin_lock(&sbi->extent_lock);
 410         if (!list_empty(&en->list)) {
 411                 list_move_tail(&en->list, &sbi->extent_list);
 412                 et->cached_en = en;
 413         }
 414         spin_unlock(&sbi->extent_lock);
 415         ret = true;
 416 out:
 417         stat_inc_total_hit(sbi);
 418         read_unlock(&et->lock);
 419 
 420         trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
 421         return ret;
 422 }
 423 
 424 static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
 425                                 struct extent_tree *et, struct extent_info *ei,
 426                                 struct extent_node *prev_ex,
 427                                 struct extent_node *next_ex)
 428 {
 429         struct extent_node *en = NULL;
 430 
 431         if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
 432                 prev_ex->ei.len += ei->len;
 433                 ei = &prev_ex->ei;
 434                 en = prev_ex;
 435         }
 436 
 437         if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) {
 438                 next_ex->ei.fofs = ei->fofs;
 439                 next_ex->ei.blk = ei->blk;
 440                 next_ex->ei.len += ei->len;
 441                 if (en)
 442                         __release_extent_node(sbi, et, prev_ex);
 443 
 444                 en = next_ex;
 445         }
 446 
 447         if (!en)
 448                 return NULL;
 449 
 450         __try_update_largest_extent(et, en);
 451 
 452         spin_lock(&sbi->extent_lock);
 453         if (!list_empty(&en->list)) {
 454                 list_move_tail(&en->list, &sbi->extent_list);
 455                 et->cached_en = en;
 456         }
 457         spin_unlock(&sbi->extent_lock);
 458         return en;
 459 }
 460 
 461 static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
 462                                 struct extent_tree *et, struct extent_info *ei,
 463                                 struct rb_node **insert_p,
 464                                 struct rb_node *insert_parent,
 465                                 bool leftmost)
 466 {
 467         struct rb_node **p;
 468         struct rb_node *parent = NULL;
 469         struct extent_node *en = NULL;
 470 
 471         if (insert_p && insert_parent) {
 472                 parent = insert_parent;
 473                 p = insert_p;
 474                 goto do_insert;
 475         }
 476 
 477         leftmost = true;
 478 
 479         p = f2fs_lookup_rb_tree_for_insert(sbi, &et->root, &parent,
 480                                                 ei->fofs, &leftmost);
 481 do_insert:
 482         en = __attach_extent_node(sbi, et, ei, parent, p, leftmost);
 483         if (!en)
 484                 return NULL;
 485 
 486         __try_update_largest_extent(et, en);
 487 
 488         /* update in global extent list */
 489         spin_lock(&sbi->extent_lock);
 490         list_add_tail(&en->list, &sbi->extent_list);
 491         et->cached_en = en;
 492         spin_unlock(&sbi->extent_lock);
 493         return en;
 494 }
 495 
 496 static void f2fs_update_extent_tree_range(struct inode *inode,
 497                                 pgoff_t fofs, block_t blkaddr, unsigned int len)
 498 {
 499         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 500         struct extent_tree *et = F2FS_I(inode)->extent_tree;
 501         struct extent_node *en = NULL, *en1 = NULL;
 502         struct extent_node *prev_en = NULL, *next_en = NULL;
 503         struct extent_info ei, dei, prev;
 504         struct rb_node **insert_p = NULL, *insert_parent = NULL;
 505         unsigned int end = fofs + len;
 506         unsigned int pos = (unsigned int)fofs;
 507         bool updated = false;
 508         bool leftmost = false;
 509 
 510         if (!et)
 511                 return;
 512 
 513         trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, len);
 514 
 515         write_lock(&et->lock);
 516 
 517         if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
 518                 write_unlock(&et->lock);
 519                 return;
 520         }
 521 
 522         prev = et->largest;
 523         dei.len = 0;
 524 
 525         /*
 526          * drop largest extent before lookup, in case it's already
 527          * been shrunk from extent tree
 528          */
 529         __drop_largest_extent(et, fofs, len);
 530 
 531         /* 1. lookup first extent node in range [fofs, fofs + len - 1] */
 532         en = (struct extent_node *)f2fs_lookup_rb_tree_ret(&et->root,
 533                                         (struct rb_entry *)et->cached_en, fofs,
 534                                         (struct rb_entry **)&prev_en,
 535                                         (struct rb_entry **)&next_en,
 536                                         &insert_p, &insert_parent, false,
 537                                         &leftmost);
 538         if (!en)
 539                 en = next_en;
 540 
 541         /* 2. invlidate all extent nodes in range [fofs, fofs + len - 1] */
 542         while (en && en->ei.fofs < end) {
 543                 unsigned int org_end;
 544                 int parts = 0;  /* # of parts current extent split into */
 545 
 546                 next_en = en1 = NULL;
 547 
 548                 dei = en->ei;
 549                 org_end = dei.fofs + dei.len;
 550                 f2fs_bug_on(sbi, pos >= org_end);
 551 
 552                 if (pos > dei.fofs &&   pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
 553                         en->ei.len = pos - en->ei.fofs;
 554                         prev_en = en;
 555                         parts = 1;
 556                 }
 557 
 558                 if (end < org_end && org_end - end >= F2FS_MIN_EXTENT_LEN) {
 559                         if (parts) {
 560                                 set_extent_info(&ei, end,
 561                                                 end - dei.fofs + dei.blk,
 562                                                 org_end - end);
 563                                 en1 = __insert_extent_tree(sbi, et, &ei,
 564                                                         NULL, NULL, true);
 565                                 next_en = en1;
 566                         } else {
 567                                 en->ei.fofs = end;
 568                                 en->ei.blk += end - dei.fofs;
 569                                 en->ei.len -= end - dei.fofs;
 570                                 next_en = en;
 571                         }
 572                         parts++;
 573                 }
 574 
 575                 if (!next_en) {
 576                         struct rb_node *node = rb_next(&en->rb_node);
 577 
 578                         next_en = rb_entry_safe(node, struct extent_node,
 579                                                 rb_node);
 580                 }
 581 
 582                 if (parts)
 583                         __try_update_largest_extent(et, en);
 584                 else
 585                         __release_extent_node(sbi, et, en);
 586 
 587                 /*
 588                  * if original extent is split into zero or two parts, extent
 589                  * tree has been altered by deletion or insertion, therefore
 590                  * invalidate pointers regard to tree.
 591                  */
 592                 if (parts != 1) {
 593                         insert_p = NULL;
 594                         insert_parent = NULL;
 595                 }
 596                 en = next_en;
 597         }
 598 
 599         /* 3. update extent in extent cache */
 600         if (blkaddr) {
 601 
 602                 set_extent_info(&ei, fofs, blkaddr, len);
 603                 if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
 604                         __insert_extent_tree(sbi, et, &ei,
 605                                         insert_p, insert_parent, leftmost);
 606 
 607                 /* give up extent_cache, if split and small updates happen */
 608                 if (dei.len >= 1 &&
 609                                 prev.len < F2FS_MIN_EXTENT_LEN &&
 610                                 et->largest.len < F2FS_MIN_EXTENT_LEN) {
 611                         et->largest.len = 0;
 612                         et->largest_updated = true;
 613                         set_inode_flag(inode, FI_NO_EXTENT);
 614                 }
 615         }
 616 
 617         if (is_inode_flag_set(inode, FI_NO_EXTENT))
 618                 __free_extent_tree(sbi, et);
 619 
 620         if (et->largest_updated) {
 621                 et->largest_updated = false;
 622                 updated = true;
 623         }
 624 
 625         write_unlock(&et->lock);
 626 
 627         if (updated)
 628                 f2fs_mark_inode_dirty_sync(inode, true);
 629 }
 630 
 631 unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
 632 {
 633         struct extent_tree *et, *next;
 634         struct extent_node *en;
 635         unsigned int node_cnt = 0, tree_cnt = 0;
 636         int remained;
 637 
 638         if (!test_opt(sbi, EXTENT_CACHE))
 639                 return 0;
 640 
 641         if (!atomic_read(&sbi->total_zombie_tree))
 642                 goto free_node;
 643 
 644         if (!mutex_trylock(&sbi->extent_tree_lock))
 645                 goto out;
 646 
 647         /* 1. remove unreferenced extent tree */
 648         list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
 649                 if (atomic_read(&et->node_cnt)) {
 650                         write_lock(&et->lock);
 651                         node_cnt += __free_extent_tree(sbi, et);
 652                         write_unlock(&et->lock);
 653                 }
 654                 f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
 655                 list_del_init(&et->list);
 656                 radix_tree_delete(&sbi->extent_tree_root, et->ino);
 657                 kmem_cache_free(extent_tree_slab, et);
 658                 atomic_dec(&sbi->total_ext_tree);
 659                 atomic_dec(&sbi->total_zombie_tree);
 660                 tree_cnt++;
 661 
 662                 if (node_cnt + tree_cnt >= nr_shrink)
 663                         goto unlock_out;
 664                 cond_resched();
 665         }
 666         mutex_unlock(&sbi->extent_tree_lock);
 667 
 668 free_node:
 669         /* 2. remove LRU extent entries */
 670         if (!mutex_trylock(&sbi->extent_tree_lock))
 671                 goto out;
 672 
 673         remained = nr_shrink - (node_cnt + tree_cnt);
 674 
 675         spin_lock(&sbi->extent_lock);
 676         for (; remained > 0; remained--) {
 677                 if (list_empty(&sbi->extent_list))
 678                         break;
 679                 en = list_first_entry(&sbi->extent_list,
 680                                         struct extent_node, list);
 681                 et = en->et;
 682                 if (!write_trylock(&et->lock)) {
 683                         /* refresh this extent node's position in extent list */
 684                         list_move_tail(&en->list, &sbi->extent_list);
 685                         continue;
 686                 }
 687 
 688                 list_del_init(&en->list);
 689                 spin_unlock(&sbi->extent_lock);
 690 
 691                 __detach_extent_node(sbi, et, en);
 692 
 693                 write_unlock(&et->lock);
 694                 node_cnt++;
 695                 spin_lock(&sbi->extent_lock);
 696         }
 697         spin_unlock(&sbi->extent_lock);
 698 
 699 unlock_out:
 700         mutex_unlock(&sbi->extent_tree_lock);
 701 out:
 702         trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);
 703 
 704         return node_cnt + tree_cnt;
 705 }
 706 
 707 unsigned int f2fs_destroy_extent_node(struct inode *inode)
 708 {
 709         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 710         struct extent_tree *et = F2FS_I(inode)->extent_tree;
 711         unsigned int node_cnt = 0;
 712 
 713         if (!et || !atomic_read(&et->node_cnt))
 714                 return 0;
 715 
 716         write_lock(&et->lock);
 717         node_cnt = __free_extent_tree(sbi, et);
 718         write_unlock(&et->lock);
 719 
 720         return node_cnt;
 721 }
 722 
 723 void f2fs_drop_extent_tree(struct inode *inode)
 724 {
 725         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 726         struct extent_tree *et = F2FS_I(inode)->extent_tree;
 727         bool updated = false;
 728 
 729         if (!f2fs_may_extent_tree(inode))
 730                 return;
 731 
 732         set_inode_flag(inode, FI_NO_EXTENT);
 733 
 734         write_lock(&et->lock);
 735         __free_extent_tree(sbi, et);
 736         if (et->largest.len) {
 737                 et->largest.len = 0;
 738                 updated = true;
 739         }
 740         write_unlock(&et->lock);
 741         if (updated)
 742                 f2fs_mark_inode_dirty_sync(inode, true);
 743 }
 744 
 745 void f2fs_destroy_extent_tree(struct inode *inode)
 746 {
 747         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 748         struct extent_tree *et = F2FS_I(inode)->extent_tree;
 749         unsigned int node_cnt = 0;
 750 
 751         if (!et)
 752                 return;
 753 
 754         if (inode->i_nlink && !is_bad_inode(inode) &&
 755                                         atomic_read(&et->node_cnt)) {
 756                 mutex_lock(&sbi->extent_tree_lock);
 757                 list_add_tail(&et->list, &sbi->zombie_list);
 758                 atomic_inc(&sbi->total_zombie_tree);
 759                 mutex_unlock(&sbi->extent_tree_lock);
 760                 return;
 761         }
 762 
 763         /* free all extent info belong to this extent tree */
 764         node_cnt = f2fs_destroy_extent_node(inode);
 765 
 766         /* delete extent tree entry in radix tree */
 767         mutex_lock(&sbi->extent_tree_lock);
 768         f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
 769         radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
 770         kmem_cache_free(extent_tree_slab, et);
 771         atomic_dec(&sbi->total_ext_tree);
 772         mutex_unlock(&sbi->extent_tree_lock);
 773 
 774         F2FS_I(inode)->extent_tree = NULL;
 775 
 776         trace_f2fs_destroy_extent_tree(inode, node_cnt);
 777 }
 778 
 779 bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
 780                                         struct extent_info *ei)
 781 {
 782         if (!f2fs_may_extent_tree(inode))
 783                 return false;
 784 
 785         return f2fs_lookup_extent_tree(inode, pgofs, ei);
 786 }
 787 
 788 void f2fs_update_extent_cache(struct dnode_of_data *dn)
 789 {
 790         pgoff_t fofs;
 791         block_t blkaddr;
 792 
 793         if (!f2fs_may_extent_tree(dn->inode))
 794                 return;
 795 
 796         if (dn->data_blkaddr == NEW_ADDR)
 797                 blkaddr = NULL_ADDR;
 798         else
 799                 blkaddr = dn->data_blkaddr;
 800 
 801         fofs = f2fs_start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
 802                                                                 dn->ofs_in_node;
 803         f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, 1);
 804 }
 805 
 806 void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
 807                                 pgoff_t fofs, block_t blkaddr, unsigned int len)
 808 
 809 {
 810         if (!f2fs_may_extent_tree(dn->inode))
 811                 return;
 812 
 813         f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, len);
 814 }
 815 
 816 void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi)
 817 {
 818         INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
 819         mutex_init(&sbi->extent_tree_lock);
 820         INIT_LIST_HEAD(&sbi->extent_list);
 821         spin_lock_init(&sbi->extent_lock);
 822         atomic_set(&sbi->total_ext_tree, 0);
 823         INIT_LIST_HEAD(&sbi->zombie_list);
 824         atomic_set(&sbi->total_zombie_tree, 0);
 825         atomic_set(&sbi->total_ext_node, 0);
 826 }
 827 
 828 int __init f2fs_create_extent_cache(void)
 829 {
 830         extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree",
 831                         sizeof(struct extent_tree));
 832         if (!extent_tree_slab)
 833                 return -ENOMEM;
 834         extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node",
 835                         sizeof(struct extent_node));
 836         if (!extent_node_slab) {
 837                 kmem_cache_destroy(extent_tree_slab);
 838                 return -ENOMEM;
 839         }
 840         return 0;
 841 }
 842 
 843 void f2fs_destroy_extent_cache(void)
 844 {
 845         kmem_cache_destroy(extent_node_slab);
 846         kmem_cache_destroy(extent_tree_slab);
 847 }