fs/f2fs/node.c

   1 /*
   2  * fs/f2fs/node.c
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *             http://www.samsung.com/
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/f2fs_fs.h>
  13 #include <linux/mpage.h>
  14 #include <linux/backing-dev.h>
  15 #include <linux/blkdev.h>
  16 #include <linux/pagevec.h>
  17 #include <linux/swap.h>
  18
  19 #include "f2fs.h"
  20 #include "node.h"
  21 #include "segment.h"
  22 #include <trace/events/f2fs.h>
  23
  24 #define on_build_free_nids(nmi) mutex_is_locked(&nm_i->build_lock)
  25
  26 static struct kmem_cache *nat_entry_slab;
  27 static struct kmem_cache *free_nid_slab;
  28
  29 static void clear_node_page_dirty(struct page *page)
  30 {
  31         struct address_space *mapping = page->mapping;
  32         struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
  33         unsigned int long flags;
  34
  35         if (PageDirty(page)) {
  36                 spin_lock_irqsave(&mapping->tree_lock, flags);
  37                 radix_tree_tag_clear(&mapping->page_tree,
  38                                 page_index(page),
  39                                 PAGECACHE_TAG_DIRTY);
  40                 spin_unlock_irqrestore(&mapping->tree_lock, flags);
  41
  42                 clear_page_dirty_for_io(page);
  43                 dec_page_count(sbi, F2FS_DIRTY_NODES);
  44         }
  45         ClearPageUptodate(page);
  46 }
  47
  48 static struct page *get_current_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
  49 {
  50         pgoff_t index = current_nat_addr(sbi, nid);
  51         return get_meta_page(sbi, index);
  52 }
  53
  54 static struct page *get_next_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
  55 {
  56         struct page *src_page;
  57         struct page *dst_page;
  58         pgoff_t src_off;
  59         pgoff_t dst_off;
  60         void *src_addr;
  61         void *dst_addr;
  62         struct f2fs_nm_info *nm_i = NM_I(sbi);
  63
  64         src_off = current_nat_addr(sbi, nid);
  65         dst_off = next_nat_addr(sbi, src_off);
  66
  67         /* get current nat block page with lock */
  68         src_page = get_meta_page(sbi, src_off);
  69
  70         /* Dirty src_page means that it is already the new target NAT page. */
  71         if (PageDirty(src_page))
  72                 return src_page;
  73
  74         dst_page = grab_meta_page(sbi, dst_off);
  75
  76         src_addr = page_address(src_page);
  77         dst_addr = page_address(dst_page);
  78         memcpy(dst_addr, src_addr, PAGE_CACHE_SIZE);
  79         set_page_dirty(dst_page);
  80         f2fs_put_page(src_page, 1);
  81
  82         set_to_next_nat(nm_i, nid);
  83
  84         return dst_page;
  85 }
  86
  87 static struct nat_entry *__lookup_nat_cache(struct f2fs_nm_info *nm_i, nid_t n)
  88 {
  89         return radix_tree_lookup(&nm_i->nat_root, n);
  90 }
  91
  92 static unsigned int __gang_lookup_nat_cache(struct f2fs_nm_info *nm_i,
  93                 nid_t start, unsigned int nr, struct nat_entry **ep)
  94 {
  95         return radix_tree_gang_lookup(&nm_i->nat_root, (void **)ep, start, nr);
  96 }
  97
  98 static void __del_from_nat_cache(struct f2fs_nm_info *nm_i, struct nat_entry *e)
  99 {
 100         list_del(&e->list);
 101         radix_tree_delete(&nm_i->nat_root, nat_get_nid(e));
 102         nm_i->nat_cnt--;
 103         kmem_cache_free(nat_entry_slab, e);
 104 }
 105
 106 int is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
 107 {
 108         struct f2fs_nm_info *nm_i = NM_I(sbi);
 109         struct nat_entry *e;
 110         int is_cp = 1;
 111
 112         read_lock(&nm_i->nat_tree_lock);
 113         e = __lookup_nat_cache(nm_i, nid);
 114         if (e && !e->checkpointed)
 115                 is_cp = 0;
 116         read_unlock(&nm_i->nat_tree_lock);
 117         return is_cp;
 118 }
 119
 120 static struct nat_entry *grab_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid)
 121 {
 122         struct nat_entry *new;
 123
 124         new = kmem_cache_alloc(nat_entry_slab, GFP_ATOMIC);
 125         if (!new)
 126                 return NULL;
 127         if (radix_tree_insert(&nm_i->nat_root, nid, new)) {
 128                 kmem_cache_free(nat_entry_slab, new);
 129                 return NULL;
 130         }
 131         memset(new, 0, sizeof(struct nat_entry));
 132         nat_set_nid(new, nid);
 133         new->checkpointed = true;
 134         list_add_tail(&new->list, &nm_i->nat_entries);
 135         nm_i->nat_cnt++;
 136         return new;
 137 }
 138
 139 static void cache_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid,
 140                                                 struct f2fs_nat_entry *ne)
 141 {
 142         struct nat_entry *e;
 143 retry:
 144         write_lock(&nm_i->nat_tree_lock);
 145         e = __lookup_nat_cache(nm_i, nid);
 146         if (!e) {
 147                 e = grab_nat_entry(nm_i, nid);
 148                 if (!e) {
 149                         write_unlock(&nm_i->nat_tree_lock);
 150                         goto retry;
 151                 }
 152                 nat_set_blkaddr(e, le32_to_cpu(ne->block_addr));
 153                 nat_set_ino(e, le32_to_cpu(ne->ino));
 154                 nat_set_version(e, ne->version);
 155         }
 156         write_unlock(&nm_i->nat_tree_lock);
 157 }
 158
 159 static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
 160                         block_t new_blkaddr)
 161 {
 162         struct f2fs_nm_info *nm_i = NM_I(sbi);
 163         struct nat_entry *e;
 164 retry:
 165         write_lock(&nm_i->nat_tree_lock);
 166         e = __lookup_nat_cache(nm_i, ni->nid);
 167         if (!e) {
 168                 e = grab_nat_entry(nm_i, ni->nid);
 169                 if (!e) {
 170                         write_unlock(&nm_i->nat_tree_lock);
 171                         goto retry;
 172                 }
 173                 e->ni = *ni;
 174                 f2fs_bug_on(ni->blk_addr == NEW_ADDR);
 175         } else if (new_blkaddr == NEW_ADDR) {
 176                 /*
 177                  * when nid is reallocated,
 178                  * previous nat entry can be remained in nat cache.
 179                  * So, reinitialize it with new information.
 180                  */
 181                 e->ni = *ni;
 182                 f2fs_bug_on(ni->blk_addr != NULL_ADDR);
 183         }
 184
 185         /* sanity check */
 186         f2fs_bug_on(nat_get_blkaddr(e) != ni->blk_addr);
 187         f2fs_bug_on(nat_get_blkaddr(e) == NULL_ADDR &&
 188                         new_blkaddr == NULL_ADDR);
 189         f2fs_bug_on(nat_get_blkaddr(e) == NEW_ADDR &&
 190                         new_blkaddr == NEW_ADDR);
 191         f2fs_bug_on(nat_get_blkaddr(e) != NEW_ADDR &&
 192                         nat_get_blkaddr(e) != NULL_ADDR &&
 193                         new_blkaddr == NEW_ADDR);
 194
 195         /* increament version no as node is removed */
 196         if (nat_get_blkaddr(e) != NEW_ADDR && new_blkaddr == NULL_ADDR) {
 197                 unsigned char version = nat_get_version(e);
 198                 nat_set_version(e, inc_node_version(version));
 199         }
 200
 201         /* change address */
 202         nat_set_blkaddr(e, new_blkaddr);
 203         __set_nat_cache_dirty(nm_i, e);
 204         write_unlock(&nm_i->nat_tree_lock);
 205 }
 206
 207 int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
 208 {
 209         struct f2fs_nm_info *nm_i = NM_I(sbi);
 210
 211         if (nm_i->nat_cnt <= NM_WOUT_THRESHOLD)
 212                 return 0;
 213
 214         write_lock(&nm_i->nat_tree_lock);
 215         while (nr_shrink && !list_empty(&nm_i->nat_entries)) {
 216                 struct nat_entry *ne;
 217                 ne = list_first_entry(&nm_i->nat_entries,
 218                                         struct nat_entry, list);
 219                 __del_from_nat_cache(nm_i, ne);
 220                 nr_shrink--;
 221         }
 222         write_unlock(&nm_i->nat_tree_lock);
 223         return nr_shrink;
 224 }
 225
 226 /*
 227  * This function returns always success
 228  */
 229 void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni)
 230 {
 231         struct f2fs_nm_info *nm_i = NM_I(sbi);
 232         struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
 233         struct f2fs_summary_block *sum = curseg->sum_blk;
 234         nid_t start_nid = START_NID(nid);
 235         struct f2fs_nat_block *nat_blk;
 236         struct page *page = NULL;
 237         struct f2fs_nat_entry ne;
 238         struct nat_entry *e;
 239         int i;
 240
 241         memset(&ne, 0, sizeof(struct f2fs_nat_entry));
 242         ni->nid = nid;
 243
 244         /* Check nat cache */
 245         read_lock(&nm_i->nat_tree_lock);
 246         e = __lookup_nat_cache(nm_i, nid);
 247         if (e) {
 248                 ni->ino = nat_get_ino(e);
 249                 ni->blk_addr = nat_get_blkaddr(e);
 250                 ni->version = nat_get_version(e);
 251         }
 252         read_unlock(&nm_i->nat_tree_lock);
 253         if (e)
 254                 return;
 255
 256         /* Check current segment summary */
 257         mutex_lock(&curseg->curseg_mutex);
 258         i = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 0);
 259         if (i >= 0) {
 260                 ne = nat_in_journal(sum, i);
 261                 node_info_from_raw_nat(ni, &ne);
 262         }
 263         mutex_unlock(&curseg->curseg_mutex);
 264         if (i >= 0)
 265                 goto cache;
 266
 267         /* Fill node_info from nat page */
 268         page = get_current_nat_page(sbi, start_nid);
 269         nat_blk = (struct f2fs_nat_block *)page_address(page);
 270         ne = nat_blk->entries[nid - start_nid];
 271         node_info_from_raw_nat(ni, &ne);
 272         f2fs_put_page(page, 1);
 273 cache:
 274         /* cache nat entry */
 275         cache_nat_entry(NM_I(sbi), nid, &ne);
 276 }
 277
 278 /*
 279  * The maximum depth is four.
 280  * Offset[0] will have raw inode offset.
 281  */
 282 static int get_node_path(struct f2fs_inode_info *fi, long block,
 283                                 int offset[4], unsigned int noffset[4])
 284 {
 285         const long direct_index = ADDRS_PER_INODE(fi);
 286         const long direct_blks = ADDRS_PER_BLOCK;
 287         const long dptrs_per_blk = NIDS_PER_BLOCK;
 288         const long indirect_blks = ADDRS_PER_BLOCK * NIDS_PER_BLOCK;
 289         const long dindirect_blks = indirect_blks * NIDS_PER_BLOCK;
 290         int n = 0;
 291         int level = 0;
 292
 293         noffset[0] = 0;
 294
 295         if (block < direct_index) {
 296                 offset[n] = block;
 297                 goto got;
 298         }
 299         block -= direct_index;
 300         if (block < direct_blks) {
 301                 offset[n++] = NODE_DIR1_BLOCK;
 302                 noffset[n] = 1;
 303                 offset[n] = block;
 304                 level = 1;
 305                 goto got;
 306         }
 307         block -= direct_blks;
 308         if (block < direct_blks) {
 309                 offset[n++] = NODE_DIR2_BLOCK;
 310                 noffset[n] = 2;
 311                 offset[n] = block;
 312                 level = 1;
 313                 goto got;
 314         }
 315         block -= direct_blks;
 316         if (block < indirect_blks) {
 317                 offset[n++] = NODE_IND1_BLOCK;
 318                 noffset[n] = 3;
 319                 offset[n++] = block / direct_blks;
 320                 noffset[n] = 4 + offset[n - 1];
 321                 offset[n] = block % direct_blks;
 322                 level = 2;
 323                 goto got;
 324         }
 325         block -= indirect_blks;
 326         if (block < indirect_blks) {
 327                 offset[n++] = NODE_IND2_BLOCK;
 328                 noffset[n] = 4 + dptrs_per_blk;
 329                 offset[n++] = block / direct_blks;
 330                 noffset[n] = 5 + dptrs_per_blk + offset[n - 1];
 331                 offset[n] = block % direct_blks;
 332                 level = 2;
 333                 goto got;
 334         }
 335         block -= indirect_blks;
 336         if (block < dindirect_blks) {
 337                 offset[n++] = NODE_DIND_BLOCK;
 338                 noffset[n] = 5 + (dptrs_per_blk * 2);
 339                 offset[n++] = block / indirect_blks;
 340                 noffset[n] = 6 + (dptrs_per_blk * 2) +
 341                               offset[n - 1] * (dptrs_per_blk + 1);
 342                 offset[n++] = (block / direct_blks) % dptrs_per_blk;
 343                 noffset[n] = 7 + (dptrs_per_blk * 2) +
 344                               offset[n - 2] * (dptrs_per_blk + 1) +
 345                               offset[n - 1];
 346                 offset[n] = block % direct_blks;
 347                 level = 3;
 348                 goto got;
 349         } else {
 350                 BUG();
 351         }
 352 got:
 353         return level;
 354 }
 355
 356 /*
 357  * Caller should call f2fs_put_dnode(dn).
 358  * Also, it should grab and release a rwsem by calling f2fs_lock_op() and
 359  * f2fs_unlock_op() only if ro is not set RDONLY_NODE.
 360  * In the case of RDONLY_NODE, we don't need to care about mutex.
 361  */
 362 int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode)
 363 {
 364         struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
 365         struct page *npage[4];
 366         struct page *parent;
 367         int offset[4];
 368         unsigned int noffset[4];
 369         nid_t nids[4];
 370         int level, i;
 371         int err = 0;
 372
 373         level = get_node_path(F2FS_I(dn->inode), index, offset, noffset);
 374
 375         nids[0] = dn->inode->i_ino;
 376         npage[0] = dn->inode_page;
 377
 378         if (!npage[0]) {
 379                 npage[0] = get_node_page(sbi, nids[0]);
 380                 if (IS_ERR(npage[0]))
 381                         return PTR_ERR(npage[0]);
 382         }
 383         parent = npage[0];
 384         if (level != 0)
 385                 nids[1] = get_nid(parent, offset[0], true);
 386         dn->inode_page = npage[0];
 387         dn->inode_page_locked = true;
 388
 389         /* get indirect or direct nodes */
 390         for (i = 1; i <= level; i++) {
 391                 bool done = false;
 392
 393                 if (!nids[i] && mode == ALLOC_NODE) {
 394                         /* alloc new node */
 395                         if (!alloc_nid(sbi, &(nids[i]))) {
 396                                 err = -ENOSPC;
 397                                 goto release_pages;
 398                         }
 399
 400                         dn->nid = nids[i];
 401                         npage[i] = new_node_page(dn, noffset[i], NULL);
 402                         if (IS_ERR(npage[i])) {
 403                                 alloc_nid_failed(sbi, nids[i]);
 404                                 err = PTR_ERR(npage[i]);
 405                                 goto release_pages;
 406                         }
 407
 408                         set_nid(parent, offset[i - 1], nids[i], i == 1);
 409                         alloc_nid_done(sbi, nids[i]);
 410                         done = true;
 411                 } else if (mode == LOOKUP_NODE_RA && i == level && level > 1) {
 412                         npage[i] = get_node_page_ra(parent, offset[i - 1]);
 413                         if (IS_ERR(npage[i])) {
 414                                 err = PTR_ERR(npage[i]);
 415                                 goto release_pages;
 416                         }
 417                         done = true;
 418                 }
 419                 if (i == 1) {
 420                         dn->inode_page_locked = false;
 421                         unlock_page(parent);
 422                 } else {
 423                         f2fs_put_page(parent, 1);
 424                 }
 425
 426                 if (!done) {
 427                         npage[i] = get_node_page(sbi, nids[i]);
 428                         if (IS_ERR(npage[i])) {
 429                                 err = PTR_ERR(npage[i]);
 430                                 f2fs_put_page(npage[0], 0);
 431                                 goto release_out;
 432                         }
 433                 }
 434                 if (i < level) {
 435                         parent = npage[i];
 436                         nids[i + 1] = get_nid(parent, offset[i], false);
 437                 }
 438         }
 439         dn->nid = nids[level];
 440         dn->ofs_in_node = offset[level];
 441         dn->node_page = npage[level];
 442         dn->data_blkaddr = datablock_addr(dn->node_page, dn->ofs_in_node);
 443         return 0;
 444
 445 release_pages:
 446         f2fs_put_page(parent, 1);
 447         if (i > 1)
 448                 f2fs_put_page(npage[0], 0);
 449 release_out:
 450         dn->inode_page = NULL;
 451         dn->node_page = NULL;
 452         return err;
 453 }
 454
 455 static void truncate_node(struct dnode_of_data *dn)
 456 {
 457         struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
 458         struct node_info ni;
 459
 460         get_node_info(sbi, dn->nid, &ni);
 461         if (dn->inode->i_blocks == 0) {
 462                 f2fs_bug_on(ni.blk_addr != NULL_ADDR);
 463                 goto invalidate;
 464         }
 465         f2fs_bug_on(ni.blk_addr == NULL_ADDR);
 466
 467         /* Deallocate node address */
 468         invalidate_blocks(sbi, ni.blk_addr);
 469         dec_valid_node_count(sbi, dn->inode);
 470         set_node_addr(sbi, &ni, NULL_ADDR);
 471
 472         if (dn->nid == dn->inode->i_ino) {
 473                 remove_orphan_inode(sbi, dn->nid);
 474                 dec_valid_inode_count(sbi);
 475         } else {
 476                 sync_inode_page(dn);
 477         }
 478 invalidate:
 479         clear_node_page_dirty(dn->node_page);
 480         F2FS_SET_SB_DIRT(sbi);
 481
 482         f2fs_put_page(dn->node_page, 1);
 483
 484         invalidate_mapping_pages(NODE_MAPPING(sbi),
 485                         dn->node_page->index, dn->node_page->index);
 486
 487         dn->node_page = NULL;
 488         trace_f2fs_truncate_node(dn->inode, dn->nid, ni.blk_addr);
 489 }
 490
 491 static int truncate_dnode(struct dnode_of_data *dn)
 492 {
 493         struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
 494         struct page *page;
 495
 496         if (dn->nid == 0)
 497                 return 1;
 498
 499         /* get direct node */
 500         page = get_node_page(sbi, dn->nid);
 501         if (IS_ERR(page) && PTR_ERR(page) == -ENOENT)
 502                 return 1;
 503         else if (IS_ERR(page))
 504                 return PTR_ERR(page);
 505
 506         /* Make dnode_of_data for parameter */
 507         dn->node_page = page;
 508         dn->ofs_in_node = 0;
 509         truncate_data_blocks(dn);
 510         truncate_node(dn);
 511         return 1;
 512 }
 513
 514 static int truncate_nodes(struct dnode_of_data *dn, unsigned int nofs,
 515                                                 int ofs, int depth)
 516 {
 517         struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
 518         struct dnode_of_data rdn = *dn;
 519         struct page *page;
 520         struct f2fs_node *rn;
 521         nid_t child_nid;
 522         unsigned int child_nofs;
 523         int freed = 0;
 524         int i, ret;
 525
 526         if (dn->nid == 0)
 527                 return NIDS_PER_BLOCK + 1;
 528
 529         trace_f2fs_truncate_nodes_enter(dn->inode, dn->nid, dn->data_blkaddr);
 530
 531         page = get_node_page(sbi, dn->nid);
 532         if (IS_ERR(page)) {
 533                 trace_f2fs_truncate_nodes_exit(dn->inode, PTR_ERR(page));
 534                 return PTR_ERR(page);
 535         }
 536
 537         rn = F2FS_NODE(page);
 538         if (depth < 3) {
 539                 for (i = ofs; i < NIDS_PER_BLOCK; i++, freed++) {
 540                         child_nid = le32_to_cpu(rn->in.nid[i]);
 541                         if (child_nid == 0)
 542                                 continue;
 543                         rdn.nid = child_nid;
 544                         ret = truncate_dnode(&rdn);
 545                         if (ret < 0)
 546                                 goto out_err;
 547                         set_nid(page, i, 0, false);
 548                 }
 549         } else {
 550                 child_nofs = nofs + ofs * (NIDS_PER_BLOCK + 1) + 1;
 551                 for (i = ofs; i < NIDS_PER_BLOCK; i++) {
 552                         child_nid = le32_to_cpu(rn->in.nid[i]);
 553                         if (child_nid == 0) {
 554                                 child_nofs += NIDS_PER_BLOCK + 1;
 555                                 continue;
 556                         }
 557                         rdn.nid = child_nid;
 558                         ret = truncate_nodes(&rdn, child_nofs, 0, depth - 1);
 559                         if (ret == (NIDS_PER_BLOCK + 1)) {
 560                                 set_nid(page, i, 0, false);
 561                                 child_nofs += ret;
 562                         } else if (ret < 0 && ret != -ENOENT) {
 563                                 goto out_err;
 564                         }
 565                 }
 566                 freed = child_nofs;
 567         }
 568
 569         if (!ofs) {
 570                 /* remove current indirect node */
 571                 dn->node_page = page;
 572                 truncate_node(dn);
 573                 freed++;
 574         } else {
 575                 f2fs_put_page(page, 1);
 576         }
 577         trace_f2fs_truncate_nodes_exit(dn->inode, freed);
 578         return freed;
 579
 580 out_err:
 581         f2fs_put_page(page, 1);
 582         trace_f2fs_truncate_nodes_exit(dn->inode, ret);
 583         return ret;
 584 }
 585
 586 static int truncate_partial_nodes(struct dnode_of_data *dn,
 587                         struct f2fs_inode *ri, int *offset, int depth)
 588 {
 589         struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
 590         struct page *pages[2];
 591         nid_t nid[3];
 592         nid_t child_nid;
 593         int err = 0;
 594         int i;
 595         int idx = depth - 2;
 596
 597         nid[0] = le32_to_cpu(ri->i_nid[offset[0] - NODE_DIR1_BLOCK]);
 598         if (!nid[0])
 599                 return 0;
 600
 601         /* get indirect nodes in the path */
 602         for (i = 0; i < idx + 1; i++) {
 603                 /* refernece count'll be increased */
 604                 pages[i] = get_node_page(sbi, nid[i]);
 605                 if (IS_ERR(pages[i])) {
 606                         err = PTR_ERR(pages[i]);
 607                         idx = i - 1;
 608                         goto fail;
 609                 }
 610                 nid[i + 1] = get_nid(pages[i], offset[i + 1], false);
 611         }
 612
 613         /* free direct nodes linked to a partial indirect node */
 614         for (i = offset[idx + 1]; i < NIDS_PER_BLOCK; i++) {
 615                 child_nid = get_nid(pages[idx], i, false);
 616                 if (!child_nid)
 617                         continue;
 618                 dn->nid = child_nid;
 619                 err = truncate_dnode(dn);
 620                 if (err < 0)
 621                         goto fail;
 622                 set_nid(pages[idx], i, 0, false);
 623         }
 624
 625         if (offset[idx + 1] == 0) {
 626                 dn->node_page = pages[idx];
 627                 dn->nid = nid[idx];
 628                 truncate_node(dn);
 629         } else {
 630                 f2fs_put_page(pages[idx], 1);
 631         }
 632         offset[idx]++;
 633         offset[idx + 1] = 0;
 634         idx--;
 635 fail:
 636         for (i = idx; i >= 0; i--)
 637                 f2fs_put_page(pages[i], 1);
 638
 639         trace_f2fs_truncate_partial_nodes(dn->inode, nid, depth, err);
 640
 641         return err;
 642 }
 643
 644 /*
 645  * All the block addresses of data and nodes should be nullified.
 646  */
 647 int truncate_inode_blocks(struct inode *inode, pgoff_t from)
 648 {
 649         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 650         int err = 0, cont = 1;
 651         int level, offset[4], noffset[4];
 652         unsigned int nofs = 0;
 653         struct f2fs_inode *ri;
 654         struct dnode_of_data dn;
 655         struct page *page;
 656
 657         trace_f2fs_truncate_inode_blocks_enter(inode, from);
 658
 659         level = get_node_path(F2FS_I(inode), from, offset, noffset);
 660 restart:
 661         page = get_node_page(sbi, inode->i_ino);
 662         if (IS_ERR(page)) {
 663                 trace_f2fs_truncate_inode_blocks_exit(inode, PTR_ERR(page));
 664                 return PTR_ERR(page);
 665         }
 666
 667         set_new_dnode(&dn, inode, page, NULL, 0);
 668         unlock_page(page);
 669
 670         ri = F2FS_INODE(page);
 671         switch (level) {
 672         case 0:
 673         case 1:
 674                 nofs = noffset[1];
 675                 break;
 676         case 2:
 677                 nofs = noffset[1];
 678                 if (!offset[level - 1])
 679                         goto skip_partial;
 680                 err = truncate_partial_nodes(&dn, ri, offset, level);
 681                 if (err < 0 && err != -ENOENT)
 682                         goto fail;
 683                 nofs += 1 + NIDS_PER_BLOCK;
 684                 break;
 685         case 3:
 686                 nofs = 5 + 2 * NIDS_PER_BLOCK;
 687                 if (!offset[level - 1])
 688                         goto skip_partial;
 689                 err = truncate_partial_nodes(&dn, ri, offset, level);
 690                 if (err < 0 && err != -ENOENT)
 691                         goto fail;
 692                 break;
 693         default:
 694                 BUG();
 695         }
 696
 697 skip_partial:
 698         while (cont) {
 699                 dn.nid = le32_to_cpu(ri->i_nid[offset[0] - NODE_DIR1_BLOCK]);
 700                 switch (offset[0]) {
 701                 case NODE_DIR1_BLOCK:
 702                 case NODE_DIR2_BLOCK:
 703                         err = truncate_dnode(&dn);
 704                         break;
 705
 706                 case NODE_IND1_BLOCK:
 707                 case NODE_IND2_BLOCK:
 708                         err = truncate_nodes(&dn, nofs, offset[1], 2);
 709                         break;
 710
 711                 case NODE_DIND_BLOCK:
 712                         err = truncate_nodes(&dn, nofs, offset[1], 3);
 713                         cont = 0;
 714                         break;
 715
 716                 default:
 717                         BUG();
 718                 }
 719                 if (err < 0 && err != -ENOENT)
 720                         goto fail;
 721                 if (offset[1] == 0 &&
 722                                 ri->i_nid[offset[0] - NODE_DIR1_BLOCK]) {
 723                         lock_page(page);
 724                         if (unlikely(page->mapping != NODE_MAPPING(sbi))) {
 725                                 f2fs_put_page(page, 1);
 726                                 goto restart;
 727                         }
 728                         wait_on_page_writeback(page);
 729                         ri->i_nid[offset[0] - NODE_DIR1_BLOCK] = 0;
 730                         set_page_dirty(page);
 731                         unlock_page(page);
 732                 }
 733                 offset[1] = 0;
 734                 offset[0]++;
 735                 nofs += err;
 736         }
 737 fail:
 738         f2fs_put_page(page, 0);
 739         trace_f2fs_truncate_inode_blocks_exit(inode, err);
 740         return err > 0 ? 0 : err;
 741 }
 742
 743 int truncate_xattr_node(struct inode *inode, struct page *page)
 744 {
 745         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 746         nid_t nid = F2FS_I(inode)->i_xattr_nid;
 747         struct dnode_of_data dn;
 748         struct page *npage;
 749
 750         if (!nid)
 751                 return 0;
 752
 753         npage = get_node_page(sbi, nid);
 754         if (IS_ERR(npage))
 755                 return PTR_ERR(npage);
 756
 757         F2FS_I(inode)->i_xattr_nid = 0;
 758
 759         /* need to do checkpoint during fsync */
 760         F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
 761
 762         set_new_dnode(&dn, inode, page, npage, nid);
 763
 764         if (page)
 765                 dn.inode_page_locked = true;
 766         truncate_node(&dn);
 767         return 0;
 768 }
 769
 770 /*
 771  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
 772  * f2fs_unlock_op().
 773  */
 774 void remove_inode_page(struct inode *inode)
 775 {
 776         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 777         struct page *page;
 778         nid_t ino = inode->i_ino;
 779         struct dnode_of_data dn;
 780
 781         page = get_node_page(sbi, ino);
 782         if (IS_ERR(page))
 783                 return;
 784
 785         if (truncate_xattr_node(inode, page)) {
 786                 f2fs_put_page(page, 1);
 787                 return;
 788         }
 789         /* 0 is possible, after f2fs_new_inode() is failed */
 790         f2fs_bug_on(inode->i_blocks != 0 && inode->i_blocks != 1);
 791         set_new_dnode(&dn, inode, page, page, ino);
 792         truncate_node(&dn);
 793 }
 794
 795 struct page *new_inode_page(struct inode *inode, const struct qstr *name)
 796 {
 797         struct dnode_of_data dn;
 798
 799         /* allocate inode page for new inode */
 800         set_new_dnode(&dn, inode, NULL, NULL, inode->i_ino);
 801
 802         /* caller should f2fs_put_page(page, 1); */
 803         return new_node_page(&dn, 0, NULL);
 804 }
 805
 806 struct page *new_node_page(struct dnode_of_data *dn,
 807                                 unsigned int ofs, struct page *ipage)
 808 {
 809         struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
 810         struct node_info old_ni, new_ni;
 811         struct page *page;
 812         int err;
 813
 814         if (unlikely(is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC)))
 815                 return ERR_PTR(-EPERM);
 816
 817         page = grab_cache_page(NODE_MAPPING(sbi), dn->nid);
 818         if (!page)
 819                 return ERR_PTR(-ENOMEM);
 820
 821         if (unlikely(!inc_valid_node_count(sbi, dn->inode))) {
 822                 err = -ENOSPC;
 823                 goto fail;
 824         }
 825
 826         get_node_info(sbi, dn->nid, &old_ni);
 827
 828         /* Reinitialize old_ni with new node page */
 829         f2fs_bug_on(old_ni.blk_addr != NULL_ADDR);
 830         new_ni = old_ni;
 831         new_ni.ino = dn->inode->i_ino;
 832         set_node_addr(sbi, &new_ni, NEW_ADDR);
 833
 834         fill_node_footer(page, dn->nid, dn->inode->i_ino, ofs, true);
 835         set_cold_node(dn->inode, page);
 836         SetPageUptodate(page);
 837         set_page_dirty(page);
 838
 839         if (ofs == XATTR_NODE_OFFSET)
 840                 F2FS_I(dn->inode)->i_xattr_nid = dn->nid;
 841
 842         dn->node_page = page;
 843         if (ipage)
 844                 update_inode(dn->inode, ipage);
 845         else
 846                 sync_inode_page(dn);
 847         if (ofs == 0)
 848                 inc_valid_inode_count(sbi);
 849
 850         return page;
 851
 852 fail:
 853         clear_node_page_dirty(page);
 854         f2fs_put_page(page, 1);
 855         return ERR_PTR(err);
 856 }
 857
 858 /*
 859  * Caller should do after getting the following values.
 860  * 0: f2fs_put_page(page, 0)
 861  * LOCKED_PAGE: f2fs_put_page(page, 1)
 862  * error: nothing
 863  */
 864 static int read_node_page(struct page *page, int rw)
 865 {
 866         struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
 867         struct node_info ni;
 868
 869         get_node_info(sbi, page->index, &ni);
 870
 871         if (unlikely(ni.blk_addr == NULL_ADDR)) {
 872                 f2fs_put_page(page, 1);
 873                 return -ENOENT;
 874         }
 875
 876         if (PageUptodate(page))
 877                 return LOCKED_PAGE;
 878
 879         return f2fs_submit_page_bio(sbi, page, ni.blk_addr, rw);
 880 }
 881
 882 /*
 883  * Readahead a node page
 884  */
 885 void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
 886 {
 887         struct page *apage;
 888         int err;
 889
 890         apage = find_get_page(NODE_MAPPING(sbi), nid);
 891         if (apage && PageUptodate(apage)) {
 892                 f2fs_put_page(apage, 0);
 893                 return;
 894         }
 895         f2fs_put_page(apage, 0);
 896
 897         apage = grab_cache_page(NODE_MAPPING(sbi), nid);
 898         if (!apage)
 899                 return;
 900
 901         err = read_node_page(apage, READA);
 902         if (err == 0)
 903                 f2fs_put_page(apage, 0);
 904         else if (err == LOCKED_PAGE)
 905                 f2fs_put_page(apage, 1);
 906 }
 907
 908 struct page *get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid)
 909 {
 910         struct page *page;
 911         int err;
 912 repeat:
 913         page = grab_cache_page(NODE_MAPPING(sbi), nid);
 914         if (!page)
 915                 return ERR_PTR(-ENOMEM);
 916
 917         err = read_node_page(page, READ_SYNC);
 918         if (err < 0)
 919                 return ERR_PTR(err);
 920         else if (err == LOCKED_PAGE)
 921                 goto got_it;
 922
 923         lock_page(page);
 924         if (unlikely(!PageUptodate(page))) {
 925                 f2fs_put_page(page, 1);
 926                 return ERR_PTR(-EIO);
 927         }
 928         if (unlikely(page->mapping != NODE_MAPPING(sbi))) {
 929                 f2fs_put_page(page, 1);
 930                 goto repeat;
 931         }
 932 got_it:
 933         f2fs_bug_on(nid != nid_of_node(page));
 934         mark_page_accessed(page);
 935         return page;
 936 }
 937
 938 /*
 939  * Return a locked page for the desired node page.
 940  * And, readahead MAX_RA_NODE number of node pages.
 941  */
 942 struct page *get_node_page_ra(struct page *parent, int start)
 943 {
 944         struct f2fs_sb_info *sbi = F2FS_SB(parent->mapping->host->i_sb);
 945         struct blk_plug plug;
 946         struct page *page;
 947         int err, i, end;
 948         nid_t nid;
 949
 950         /* First, try getting the desired direct node. */
 951         nid = get_nid(parent, start, false);
 952         if (!nid)
 953                 return ERR_PTR(-ENOENT);
 954 repeat:
 955         page = grab_cache_page(NODE_MAPPING(sbi), nid);
 956         if (!page)
 957                 return ERR_PTR(-ENOMEM);
 958
 959         err = read_node_page(page, READ_SYNC);
 960         if (err < 0)
 961                 return ERR_PTR(err);
 962         else if (err == LOCKED_PAGE)
 963                 goto page_hit;
 964
 965         blk_start_plug(&plug);
 966
 967         /* Then, try readahead for siblings of the desired node */
 968         end = start + MAX_RA_NODE;
 969         end = min(end, NIDS_PER_BLOCK);
 970         for (i = start + 1; i < end; i++) {
 971                 nid = get_nid(parent, i, false);
 972                 if (!nid)
 973                         continue;
 974                 ra_node_page(sbi, nid);
 975         }
 976
 977         blk_finish_plug(&plug);
 978
 979         lock_page(page);
 980         if (unlikely(page->mapping != NODE_MAPPING(sbi))) {
 981                 f2fs_put_page(page, 1);
 982                 goto repeat;
 983         }
 984 page_hit:
 985         if (unlikely(!PageUptodate(page))) {
 986                 f2fs_put_page(page, 1);
 987                 return ERR_PTR(-EIO);
 988         }
 989         mark_page_accessed(page);
 990         return page;
 991 }
 992
 993 void sync_inode_page(struct dnode_of_data *dn)
 994 {
 995         if (IS_INODE(dn->node_page) || dn->inode_page == dn->node_page) {
 996                 update_inode(dn->inode, dn->node_page);
 997         } else if (dn->inode_page) {
 998                 if (!dn->inode_page_locked)
 999                         lock_page(dn->inode_page);
1000                 update_inode(dn->inode, dn->inode_page);
1001                 if (!dn->inode_page_locked)
1002                         unlock_page(dn->inode_page);
1003         } else {
1004                 update_inode_page(dn->inode);
1005         }
1006 }
1007
1008 int sync_node_pages(struct f2fs_sb_info *sbi, nid_t ino,
1009                                         struct writeback_control *wbc)
1010 {
1011         pgoff_t index, end;
1012         struct pagevec pvec;
1013         int step = ino ? 2 : 0;
1014         int nwritten = 0, wrote = 0;
1015
1016         pagevec_init(&pvec, 0);
1017
1018 next_step:
1019         index = 0;
1020         end = LONG_MAX;
1021
1022         while (index <= end) {
1023                 int i, nr_pages;
1024                 nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
1025                                 PAGECACHE_TAG_DIRTY,
1026                                 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
1027                 if (nr_pages == 0)
1028                         break;
1029
1030                 for (i = 0; i < nr_pages; i++) {
1031                         struct page *page = pvec.pages[i];
1032
1033                         /*
1034                          * flushing sequence with step:
1035                          * 0. indirect nodes
1036                          * 1. dentry dnodes
1037                          * 2. file dnodes
1038                          */
1039                         if (step == 0 && IS_DNODE(page))
1040                                 continue;
1041                         if (step == 1 && (!IS_DNODE(page) ||
1042                                                 is_cold_node(page)))
1043                                 continue;
1044                         if (step == 2 && (!IS_DNODE(page) ||
1045                                                 !is_cold_node(page)))
1046                                 continue;
1047
1048                         /*
1049                          * If an fsync mode,
1050                          * we should not skip writing node pages.
1051                          */
1052                         if (ino && ino_of_node(page) == ino)
1053                                 lock_page(page);
1054                         else if (!trylock_page(page))
1055                                 continue;
1056
1057                         if (unlikely(page->mapping != NODE_MAPPING(sbi))) {
1058 continue_unlock:
1059                                 unlock_page(page);
1060                                 continue;
1061                         }
1062                         if (ino && ino_of_node(page) != ino)
1063                                 goto continue_unlock;
1064
1065                         if (!PageDirty(page)) {
1066                                 /* someone wrote it for us */
1067                                 goto continue_unlock;
1068                         }
1069
1070                         if (!clear_page_dirty_for_io(page))
1071                                 goto continue_unlock;
1072
1073                         /* called by fsync() */
1074                         if (ino && IS_DNODE(page)) {
1075                                 int mark = !is_checkpointed_node(sbi, ino);
1076                                 set_fsync_mark(page, 1);
1077                                 if (IS_INODE(page))
1078                                         set_dentry_mark(page, mark);
1079                                 nwritten++;
1080                         } else {
1081                                 set_fsync_mark(page, 0);
1082                                 set_dentry_mark(page, 0);
1083                         }
1084                         NODE_MAPPING(sbi)->a_ops->writepage(page, wbc);
1085                         wrote++;
1086
1087                         if (--wbc->nr_to_write == 0)
1088                                 break;
1089                 }
1090                 pagevec_release(&pvec);
1091                 cond_resched();
1092
1093                 if (wbc->nr_to_write == 0) {
1094                         step = 2;
1095                         break;
1096                 }
1097         }
1098
1099         if (step < 2) {
1100                 step++;
1101                 goto next_step;
1102         }
1103
1104         if (wrote)
1105                 f2fs_submit_merged_bio(sbi, NODE, WRITE);
1106         return nwritten;
1107 }
1108
1109 int wait_on_node_pages_writeback(struct f2fs_sb_info *sbi, nid_t ino)
1110 {
1111         pgoff_t index = 0, end = LONG_MAX;
1112         struct pagevec pvec;
1113         int ret2 = 0, ret = 0;
1114
1115         pagevec_init(&pvec, 0);
1116
1117         while (index <= end) {
1118                 int i, nr_pages;
1119                 nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
1120                                 PAGECACHE_TAG_WRITEBACK,
1121                                 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
1122                 if (nr_pages == 0)
1123                         break;
1124
1125                 for (i = 0; i < nr_pages; i++) {
1126                         struct page *page = pvec.pages[i];
1127
1128                         /* until radix tree lookup accepts end_index */
1129                         if (unlikely(page->index > end))
1130                                 continue;
1131
1132                         if (ino && ino_of_node(page) == ino) {
1133                                 wait_on_page_writeback(page);
1134                                 if (TestClearPageError(page))
1135                                         ret = -EIO;
1136                         }
1137                 }
1138                 pagevec_release(&pvec);
1139                 cond_resched();
1140         }
1141
1142         if (unlikely(test_and_clear_bit(AS_ENOSPC, &NODE_MAPPING(sbi)->flags)))
1143                 ret2 = -ENOSPC;
1144         if (unlikely(test_and_clear_bit(AS_EIO, &NODE_MAPPING(sbi)->flags)))
1145                 ret2 = -EIO;
1146         if (!ret)
1147                 ret = ret2;
1148         return ret;
1149 }
1150
1151 static int f2fs_write_node_page(struct page *page,
1152                                 struct writeback_control *wbc)
1153 {
1154         struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
1155         nid_t nid;
1156         block_t new_addr;
1157         struct node_info ni;
1158         struct f2fs_io_info fio = {
1159                 .type = NODE,
1160                 .rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE,
1161         };
1162
1163         if (unlikely(sbi->por_doing))
1164                 goto redirty_out;
1165
1166         wait_on_page_writeback(page);
1167
1168         /* get old block addr of this node page */
1169         nid = nid_of_node(page);
1170         f2fs_bug_on(page->index != nid);
1171
1172         get_node_info(sbi, nid, &ni);
1173
1174         /* This page is already truncated */
1175         if (unlikely(ni.blk_addr == NULL_ADDR)) {
1176                 dec_page_count(sbi, F2FS_DIRTY_NODES);
1177                 unlock_page(page);
1178                 return 0;
1179         }
1180
1181         if (wbc->for_reclaim)
1182                 goto redirty_out;
1183
1184         mutex_lock(&sbi->node_write);
1185         set_page_writeback(page);
1186         write_node_page(sbi, page, &fio, nid, ni.blk_addr, &new_addr);
1187         set_node_addr(sbi, &ni, new_addr);
1188         dec_page_count(sbi, F2FS_DIRTY_NODES);
1189         mutex_unlock(&sbi->node_write);
1190         unlock_page(page);
1191         return 0;
1192
1193 redirty_out:
1194         dec_page_count(sbi, F2FS_DIRTY_NODES);
1195         wbc->pages_skipped++;
1196         account_page_redirty(page);
1197         set_page_dirty(page);
1198         return AOP_WRITEPAGE_ACTIVATE;
1199 }
1200
1201 /*
1202  * It is very important to gather dirty pages and write at once, so that we can
1203  * submit a big bio without interfering other data writes.
1204  * Be default, 512 pages (2MB) * 3 node types, is more reasonable.
1205  */
1206 #define COLLECT_DIRTY_NODES     1536
1207 static int f2fs_write_node_pages(struct address_space *mapping,
1208                             struct writeback_control *wbc)
1209 {
1210         struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1211         long nr_to_write = wbc->nr_to_write;
1212
1213         /* balancing f2fs's metadata in background */
1214         f2fs_balance_fs_bg(sbi);
1215
1216         /* collect a number of dirty node pages and write together */
1217         if (get_pages(sbi, F2FS_DIRTY_NODES) < COLLECT_DIRTY_NODES)
1218                 return 0;
1219
1220         /* if mounting is failed, skip writing node pages */
1221         wbc->nr_to_write = 3 * max_hw_blocks(sbi);
1222         wbc->sync_mode = WB_SYNC_NONE;
1223         sync_node_pages(sbi, 0, wbc);
1224         wbc->nr_to_write = nr_to_write - (3 * max_hw_blocks(sbi) -
1225                                                 wbc->nr_to_write);
1226         return 0;
1227 }
1228
1229 static int f2fs_set_node_page_dirty(struct page *page)
1230 {
1231         struct address_space *mapping = page->mapping;
1232         struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1233
1234         trace_f2fs_set_page_dirty(page, NODE);
1235
1236         SetPageUptodate(page);
1237         if (!PageDirty(page)) {
1238                 __set_page_dirty_nobuffers(page);
1239                 inc_page_count(sbi, F2FS_DIRTY_NODES);
1240                 SetPagePrivate(page);
1241                 return 1;
1242         }
1243         return 0;
1244 }
1245
1246 static void f2fs_invalidate_node_page(struct page *page, unsigned int offset,
1247                                       unsigned int length)
1248 {
1249         struct inode *inode = page->mapping->host;
1250         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
1251         if (PageDirty(page))
1252                 dec_page_count(sbi, F2FS_DIRTY_NODES);
1253         ClearPagePrivate(page);
1254 }
1255
1256 static int f2fs_release_node_page(struct page *page, gfp_t wait)
1257 {
1258         ClearPagePrivate(page);
1259         return 1;
1260 }
1261
1262 /*
1263  * Structure of the f2fs node operations
1264  */
1265 const struct address_space_operations f2fs_node_aops = {
1266         .writepage      = f2fs_write_node_page,
1267         .writepages     = f2fs_write_node_pages,
1268         .set_page_dirty = f2fs_set_node_page_dirty,
1269         .invalidatepage = f2fs_invalidate_node_page,
1270         .releasepage    = f2fs_release_node_page,
1271 };
1272
1273 static struct free_nid *__lookup_free_nid_list(struct f2fs_nm_info *nm_i,
1274                                                 nid_t n)
1275 {
1276         return radix_tree_lookup(&nm_i->free_nid_root, n);
1277 }
1278
1279 static void __del_from_free_nid_list(struct f2fs_nm_info *nm_i,
1280                                                 struct free_nid *i)
1281 {
1282         list_del(&i->list);
1283         radix_tree_delete(&nm_i->free_nid_root, i->nid);
1284         kmem_cache_free(free_nid_slab, i);
1285 }
1286
1287 static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build)
1288 {
1289         struct free_nid *i;
1290         struct nat_entry *ne;
1291         bool allocated = false;
1292
1293         if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
1294                 return -1;
1295
1296         /* 0 nid should not be used */
1297         if (unlikely(nid == 0))
1298                 return 0;
1299
1300         if (build) {
1301                 /* do not add allocated nids */
1302                 read_lock(&nm_i->nat_tree_lock);
1303                 ne = __lookup_nat_cache(nm_i, nid);
1304                 if (ne &&
1305                         (!ne->checkpointed || nat_get_blkaddr(ne) != NULL_ADDR))
1306                         allocated = true;
1307                 read_unlock(&nm_i->nat_tree_lock);
1308                 if (allocated)
1309                         return 0;
1310         }
1311
1312         i = f2fs_kmem_cache_alloc(free_nid_slab, GFP_NOFS);
1313         i->nid = nid;
1314         i->state = NID_NEW;
1315
1316         spin_lock(&nm_i->free_nid_list_lock);
1317         if (radix_tree_insert(&nm_i->free_nid_root, i->nid, i)) {
1318                 spin_unlock(&nm_i->free_nid_list_lock);
1319                 kmem_cache_free(free_nid_slab, i);
1320                 return 0;
1321         }
1322         list_add_tail(&i->list, &nm_i->free_nid_list);
1323         nm_i->fcnt++;
1324         spin_unlock(&nm_i->free_nid_list_lock);
1325         return 1;
1326 }
1327
1328 static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
1329 {
1330         struct free_nid *i;
1331         spin_lock(&nm_i->free_nid_list_lock);
1332         i = __lookup_free_nid_list(nm_i, nid);
1333         if (i && i->state == NID_NEW) {
1334                 __del_from_free_nid_list(nm_i, i);
1335                 nm_i->fcnt--;
1336         }
1337         spin_unlock(&nm_i->free_nid_list_lock);
1338 }
1339
1340 static void scan_nat_page(struct f2fs_nm_info *nm_i,
1341                         struct page *nat_page, nid_t start_nid)
1342 {
1343         struct f2fs_nat_block *nat_blk = page_address(nat_page);
1344         block_t blk_addr;
1345         int i;
1346
1347         i = start_nid % NAT_ENTRY_PER_BLOCK;
1348
1349         for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
1350
1351                 if (unlikely(start_nid >= nm_i->max_nid))
1352                         break;
1353
1354                 blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
1355                 f2fs_bug_on(blk_addr == NEW_ADDR);
1356                 if (blk_addr == NULL_ADDR) {
1357                         if (add_free_nid(nm_i, start_nid, true) < 0)
1358                                 break;
1359                 }
1360         }
1361 }
1362
1363 static void build_free_nids(struct f2fs_sb_info *sbi)
1364 {
1365         struct f2fs_nm_info *nm_i = NM_I(sbi);
1366         struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1367         struct f2fs_summary_block *sum = curseg->sum_blk;
1368         int i = 0;
1369         nid_t nid = nm_i->next_scan_nid;
1370
1371         /* Enough entries */
1372         if (nm_i->fcnt > NAT_ENTRY_PER_BLOCK)
1373                 return;
1374
1375         /* readahead nat pages to be scanned */
1376         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), FREE_NID_PAGES, META_NAT);
1377
1378         while (1) {
1379                 struct page *page = get_current_nat_page(sbi, nid);
1380
1381                 scan_nat_page(nm_i, page, nid);
1382                 f2fs_put_page(page, 1);
1383
1384                 nid += (NAT_ENTRY_PER_BLOCK - (nid % NAT_ENTRY_PER_BLOCK));
1385                 if (unlikely(nid >= nm_i->max_nid))
1386                         nid = 0;
1387
1388                 if (i++ == FREE_NID_PAGES)
1389                         break;
1390         }
1391
1392         /* go to the next free nat pages to find free nids abundantly */
1393         nm_i->next_scan_nid = nid;
1394
1395         /* find free nids from current sum_pages */
1396         mutex_lock(&curseg->curseg_mutex);
1397         for (i = 0; i < nats_in_cursum(sum); i++) {
1398                 block_t addr = le32_to_cpu(nat_in_journal(sum, i).block_addr);
1399                 nid = le32_to_cpu(nid_in_journal(sum, i));
1400                 if (addr == NULL_ADDR)
1401                         add_free_nid(nm_i, nid, true);
1402                 else
1403                         remove_free_nid(nm_i, nid);
1404         }
1405         mutex_unlock(&curseg->curseg_mutex);
1406 }
1407
1408 /*
1409  * If this function returns success, caller can obtain a new nid
1410  * from second parameter of this function.
1411  * The returned nid could be used ino as well as nid when inode is created.
1412  */
1413 bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
1414 {
1415         struct f2fs_nm_info *nm_i = NM_I(sbi);
1416         struct free_nid *i = NULL;
1417         struct list_head *this;
1418 retry:
1419         if (unlikely(sbi->total_valid_node_count + 1 >= nm_i->max_nid))
1420                 return false;
1421
1422         spin_lock(&nm_i->free_nid_list_lock);
1423
1424         /* We should not use stale free nids created by build_free_nids */
1425         if (nm_i->fcnt && !on_build_free_nids(nm_i)) {
1426                 f2fs_bug_on(list_empty(&nm_i->free_nid_list));
1427                 list_for_each(this, &nm_i->free_nid_list) {
1428                         i = list_entry(this, struct free_nid, list);
1429                         if (i->state == NID_NEW)
1430                                 break;
1431                 }
1432
1433                 f2fs_bug_on(i->state != NID_NEW);
1434                 *nid = i->nid;
1435                 i->state = NID_ALLOC;
1436                 nm_i->fcnt--;
1437                 spin_unlock(&nm_i->free_nid_list_lock);
1438                 return true;
1439         }
1440         spin_unlock(&nm_i->free_nid_list_lock);
1441
1442         /* Let's scan nat pages and its caches to get free nids */
1443         mutex_lock(&nm_i->build_lock);
1444         build_free_nids(sbi);
1445         mutex_unlock(&nm_i->build_lock);
1446         goto retry;
1447 }
1448
1449 /*
1450  * alloc_nid() should be called prior to this function.
1451  */
1452 void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
1453 {
1454         struct f2fs_nm_info *nm_i = NM_I(sbi);
1455         struct free_nid *i;
1456
1457         spin_lock(&nm_i->free_nid_list_lock);
1458         i = __lookup_free_nid_list(nm_i, nid);
1459         f2fs_bug_on(!i || i->state != NID_ALLOC);
1460         __del_from_free_nid_list(nm_i, i);
1461         spin_unlock(&nm_i->free_nid_list_lock);
1462 }
1463
1464 /*
1465  * alloc_nid() should be called prior to this function.
1466  */
1467 void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
1468 {
1469         struct f2fs_nm_info *nm_i = NM_I(sbi);
1470         struct free_nid *i;
1471
1472         if (!nid)
1473                 return;
1474
1475         spin_lock(&nm_i->free_nid_list_lock);
1476         i = __lookup_free_nid_list(nm_i, nid);
1477         f2fs_bug_on(!i || i->state != NID_ALLOC);
1478         if (nm_i->fcnt > 2 * MAX_FREE_NIDS) {
1479                 __del_from_free_nid_list(nm_i, i);
1480         } else {
1481                 i->state = NID_NEW;
1482                 nm_i->fcnt++;
1483         }
1484         spin_unlock(&nm_i->free_nid_list_lock);
1485 }
1486
1487 void recover_node_page(struct f2fs_sb_info *sbi, struct page *page,
1488                 struct f2fs_summary *sum, struct node_info *ni,
1489                 block_t new_blkaddr)
1490 {
1491         rewrite_node_page(sbi, page, sum, ni->blk_addr, new_blkaddr);
1492         set_node_addr(sbi, ni, new_blkaddr);
1493         clear_node_page_dirty(page);
1494 }
1495
1496 bool recover_xattr_data(struct inode *inode, struct page *page, block_t blkaddr)
1497 {
1498         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
1499         nid_t prev_xnid = F2FS_I(inode)->i_xattr_nid;
1500         nid_t new_xnid = nid_of_node(page);
1501         struct node_info ni;
1502
1503         if (ofs_of_node(page) != XATTR_NODE_OFFSET)
1504                 return false;
1505
1506         /* 1: invalidate the previous xattr nid */
1507         if (!prev_xnid)
1508                 goto recover_xnid;
1509
1510         /* Deallocate node address */
1511         get_node_info(sbi, prev_xnid, &ni);
1512         f2fs_bug_on(ni.blk_addr == NULL_ADDR);
1513         invalidate_blocks(sbi, ni.blk_addr);
1514         dec_valid_node_count(sbi, inode);
1515         set_node_addr(sbi, &ni, NULL_ADDR);
1516
1517 recover_xnid:
1518         /* 2: allocate new xattr nid */
1519         if (unlikely(!inc_valid_node_count(sbi, inode)))
1520                 f2fs_bug_on(1);
1521
1522         remove_free_nid(NM_I(sbi), new_xnid);
1523         get_node_info(sbi, new_xnid, &ni);
1524         ni.ino = inode->i_ino;
1525         set_node_addr(sbi, &ni, NEW_ADDR);
1526         F2FS_I(inode)->i_xattr_nid = new_xnid;
1527
1528         /* 3: update xattr blkaddr */
1529         refresh_sit_entry(sbi, NEW_ADDR, blkaddr);
1530         set_node_addr(sbi, &ni, blkaddr);
1531
1532         update_inode_page(inode);
1533         return true;
1534 }
1535
1536 int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
1537 {
1538         struct f2fs_inode *src, *dst;
1539         nid_t ino = ino_of_node(page);
1540         struct node_info old_ni, new_ni;
1541         struct page *ipage;
1542
1543         ipage = grab_cache_page(NODE_MAPPING(sbi), ino);
1544         if (!ipage)
1545                 return -ENOMEM;
1546
1547         /* Should not use this inode  from free nid list */
1548         remove_free_nid(NM_I(sbi), ino);
1549
1550         get_node_info(sbi, ino, &old_ni);
1551         SetPageUptodate(ipage);
1552         fill_node_footer(ipage, ino, ino, 0, true);
1553
1554         src = F2FS_INODE(page);
1555         dst = F2FS_INODE(ipage);
1556
1557         memcpy(dst, src, (unsigned long)&src->i_ext - (unsigned long)src);
1558         dst->i_size = 0;
1559         dst->i_blocks = cpu_to_le64(1);
1560         dst->i_links = cpu_to_le32(1);
1561         dst->i_xattr_nid = 0;
1562
1563         new_ni = old_ni;
1564         new_ni.ino = ino;
1565
1566         if (unlikely(!inc_valid_node_count(sbi, NULL)))
1567                 WARN_ON(1);
1568         set_node_addr(sbi, &new_ni, NEW_ADDR);
1569         inc_valid_inode_count(sbi);
1570         f2fs_put_page(ipage, 1);
1571         return 0;
1572 }
1573
1574 /*
1575  * ra_sum_pages() merge contiguous pages into one bio and submit.
1576  * these pre-readed pages are linked in pages list.
1577  */
1578 static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
1579                                 int start, int nrpages)
1580 {
1581         struct page *page;
1582         int page_idx = start;
1583         struct f2fs_io_info fio = {
1584                 .type = META,
1585                 .rw = READ_SYNC | REQ_META | REQ_PRIO
1586         };
1587
1588         for (; page_idx < start + nrpages; page_idx++) {
1589                 /* alloc temporal page for read node summary info*/
1590                 page = alloc_page(GFP_F2FS_ZERO);
1591                 if (!page) {
1592                         struct page *tmp;
1593                         list_for_each_entry_safe(page, tmp, pages, lru) {
1594                                 list_del(&page->lru);
1595                                 unlock_page(page);
1596                                 __free_pages(page, 0);
1597                         }
1598                         return -ENOMEM;
1599                 }
1600
1601                 lock_page(page);
1602                 page->index = page_idx;
1603                 list_add_tail(&page->lru, pages);
1604         }
1605
1606         list_for_each_entry(page, pages, lru)
1607                 f2fs_submit_page_mbio(sbi, page, page->index, &fio);
1608
1609         f2fs_submit_merged_bio(sbi, META, READ);
1610         return 0;
1611 }
1612
1613 int restore_node_summary(struct f2fs_sb_info *sbi,
1614                         unsigned int segno, struct f2fs_summary_block *sum)
1615 {
1616         struct f2fs_node *rn;
1617         struct f2fs_summary *sum_entry;
1618         struct page *page, *tmp;
1619         block_t addr;
1620         int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
1621         int i, last_offset, nrpages, err = 0;
1622         LIST_HEAD(page_list);
1623
1624         /* scan the node segment */
1625         last_offset = sbi->blocks_per_seg;
1626         addr = START_BLOCK(sbi, segno);
1627         sum_entry = &sum->entries[0];
1628
1629         for (i = 0; i < last_offset; i += nrpages, addr += nrpages) {
1630                 nrpages = min(last_offset - i, bio_blocks);
1631
1632                 /* read ahead node pages */
1633                 err = ra_sum_pages(sbi, &page_list, addr, nrpages);
1634                 if (err)
1635                         return err;
1636
1637                 list_for_each_entry_safe(page, tmp, &page_list, lru) {
1638
1639                         lock_page(page);
1640                         if (unlikely(!PageUptodate(page))) {
1641                                 err = -EIO;
1642                         } else {
1643                                 rn = F2FS_NODE(page);
1644                                 sum_entry->nid = rn->footer.nid;
1645                                 sum_entry->version = 0;
1646                                 sum_entry->ofs_in_node = 0;
1647                                 sum_entry++;
1648                         }
1649
1650                         list_del(&page->lru);
1651                         unlock_page(page);
1652                         __free_pages(page, 0);
1653                 }
1654         }
1655         return err;
1656 }
1657
1658 static bool flush_nats_in_journal(struct f2fs_sb_info *sbi)
1659 {
1660         struct f2fs_nm_info *nm_i = NM_I(sbi);
1661         struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1662         struct f2fs_summary_block *sum = curseg->sum_blk;
1663         int i;
1664
1665         mutex_lock(&curseg->curseg_mutex);
1666
1667         if (nats_in_cursum(sum) < NAT_JOURNAL_ENTRIES) {
1668                 mutex_unlock(&curseg->curseg_mutex);
1669                 return false;
1670         }
1671
1672         for (i = 0; i < nats_in_cursum(sum); i++) {
1673                 struct nat_entry *ne;
1674                 struct f2fs_nat_entry raw_ne;
1675                 nid_t nid = le32_to_cpu(nid_in_journal(sum, i));
1676
1677                 raw_ne = nat_in_journal(sum, i);
1678 retry:
1679                 write_lock(&nm_i->nat_tree_lock);
1680                 ne = __lookup_nat_cache(nm_i, nid);
1681                 if (ne) {
1682                         __set_nat_cache_dirty(nm_i, ne);
1683                         write_unlock(&nm_i->nat_tree_lock);
1684                         continue;
1685                 }
1686                 ne = grab_nat_entry(nm_i, nid);
1687                 if (!ne) {
1688                         write_unlock(&nm_i->nat_tree_lock);
1689                         goto retry;
1690                 }
1691                 nat_set_blkaddr(ne, le32_to_cpu(raw_ne.block_addr));
1692                 nat_set_ino(ne, le32_to_cpu(raw_ne.ino));
1693                 nat_set_version(ne, raw_ne.version);
1694                 __set_nat_cache_dirty(nm_i, ne);
1695                 write_unlock(&nm_i->nat_tree_lock);
1696         }
1697         update_nats_in_cursum(sum, -i);
1698         mutex_unlock(&curseg->curseg_mutex);
1699         return true;
1700 }
1701
1702 /*
1703  * This function is called during the checkpointing process.
1704  */
1705 void flush_nat_entries(struct f2fs_sb_info *sbi)
1706 {
1707         struct f2fs_nm_info *nm_i = NM_I(sbi);
1708         struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1709         struct f2fs_summary_block *sum = curseg->sum_blk;
1710         struct list_head *cur, *n;
1711         struct page *page = NULL;
1712         struct f2fs_nat_block *nat_blk = NULL;
1713         nid_t start_nid = 0, end_nid = 0;
1714         bool flushed;
1715
1716         flushed = flush_nats_in_journal(sbi);
1717
1718         if (!flushed)
1719                 mutex_lock(&curseg->curseg_mutex);
1720
1721         /* 1) flush dirty nat caches */
1722         list_for_each_safe(cur, n, &nm_i->dirty_nat_entries) {
1723                 struct nat_entry *ne;
1724                 nid_t nid;
1725                 struct f2fs_nat_entry raw_ne;
1726                 int offset = -1;
1727                 block_t new_blkaddr;
1728
1729                 ne = list_entry(cur, struct nat_entry, list);
1730                 nid = nat_get_nid(ne);
1731
1732                 if (nat_get_blkaddr(ne) == NEW_ADDR)
1733                         continue;
1734                 if (flushed)
1735                         goto to_nat_page;
1736
1737                 /* if there is room for nat enries in curseg->sumpage */
1738                 offset = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 1);
1739                 if (offset >= 0) {
1740                         raw_ne = nat_in_journal(sum, offset);
1741                         goto flush_now;
1742                 }
1743 to_nat_page:
1744                 if (!page || (start_nid > nid || nid > end_nid)) {
1745                         if (page) {
1746                                 f2fs_put_page(page, 1);
1747                                 page = NULL;
1748                         }
1749                         start_nid = START_NID(nid);
1750                         end_nid = start_nid + NAT_ENTRY_PER_BLOCK - 1;
1751
1752                         /*
1753                          * get nat block with dirty flag, increased reference
1754                          * count, mapped and lock
1755                          */
1756                         page = get_next_nat_page(sbi, start_nid);
1757                         nat_blk = page_address(page);
1758                 }
1759
1760                 f2fs_bug_on(!nat_blk);
1761                 raw_ne = nat_blk->entries[nid - start_nid];
1762 flush_now:
1763                 new_blkaddr = nat_get_blkaddr(ne);
1764
1765                 raw_ne.ino = cpu_to_le32(nat_get_ino(ne));
1766                 raw_ne.block_addr = cpu_to_le32(new_blkaddr);
1767                 raw_ne.version = nat_get_version(ne);
1768
1769                 if (offset < 0) {
1770                         nat_blk->entries[nid - start_nid] = raw_ne;
1771                 } else {
1772                         nat_in_journal(sum, offset) = raw_ne;
1773                         nid_in_journal(sum, offset) = cpu_to_le32(nid);
1774                 }
1775
1776                 if (nat_get_blkaddr(ne) == NULL_ADDR &&
1777                                 add_free_nid(NM_I(sbi), nid, false) <= 0) {
1778                         write_lock(&nm_i->nat_tree_lock);
1779                         __del_from_nat_cache(nm_i, ne);
1780                         write_unlock(&nm_i->nat_tree_lock);
1781                 } else {
1782                         write_lock(&nm_i->nat_tree_lock);
1783                         __clear_nat_cache_dirty(nm_i, ne);
1784                         write_unlock(&nm_i->nat_tree_lock);
1785                 }
1786         }
1787         if (!flushed)
1788                 mutex_unlock(&curseg->curseg_mutex);
1789         f2fs_put_page(page, 1);
1790
1791         /* 2) shrink nat caches if necessary */
1792         try_to_free_nats(sbi, nm_i->nat_cnt - NM_WOUT_THRESHOLD);
1793 }
1794
1795 static int init_node_manager(struct f2fs_sb_info *sbi)
1796 {
1797         struct f2fs_super_block *sb_raw = F2FS_RAW_SUPER(sbi);
1798         struct f2fs_nm_info *nm_i = NM_I(sbi);
1799         unsigned char *version_bitmap;
1800         unsigned int nat_segs, nat_blocks;
1801
1802         nm_i->nat_blkaddr = le32_to_cpu(sb_raw->nat_blkaddr);
1803
1804         /* segment_count_nat includes pair segment so divide to 2. */
1805         nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
1806         nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
1807
1808         /* not used nids: 0, node, meta, (and root counted as valid node) */
1809         nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks - 3;
1810         nm_i->fcnt = 0;
1811         nm_i->nat_cnt = 0;
1812
1813         INIT_RADIX_TREE(&nm_i->free_nid_root, GFP_ATOMIC);
1814         INIT_LIST_HEAD(&nm_i->free_nid_list);
1815         INIT_RADIX_TREE(&nm_i->nat_root, GFP_ATOMIC);
1816         INIT_LIST_HEAD(&nm_i->nat_entries);
1817         INIT_LIST_HEAD(&nm_i->dirty_nat_entries);
1818
1819         mutex_init(&nm_i->build_lock);
1820         spin_lock_init(&nm_i->free_nid_list_lock);
1821         rwlock_init(&nm_i->nat_tree_lock);
1822
1823         nm_i->next_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
1824         nm_i->bitmap_size = __bitmap_size(sbi, NAT_BITMAP);
1825         version_bitmap = __bitmap_ptr(sbi, NAT_BITMAP);
1826         if (!version_bitmap)
1827                 return -EFAULT;
1828
1829         nm_i->nat_bitmap = kmemdup(version_bitmap, nm_i->bitmap_size,
1830                                         GFP_KERNEL);
1831         if (!nm_i->nat_bitmap)
1832                 return -ENOMEM;
1833         return 0;
1834 }
1835
1836 int build_node_manager(struct f2fs_sb_info *sbi)
1837 {
1838         int err;
1839
1840         sbi->nm_info = kzalloc(sizeof(struct f2fs_nm_info), GFP_KERNEL);
1841         if (!sbi->nm_info)
1842                 return -ENOMEM;
1843
1844         err = init_node_manager(sbi);
1845         if (err)
1846                 return err;
1847
1848         build_free_nids(sbi);
1849         return 0;
1850 }
1851
1852 void destroy_node_manager(struct f2fs_sb_info *sbi)
1853 {
1854         struct f2fs_nm_info *nm_i = NM_I(sbi);
1855         struct free_nid *i, *next_i;
1856         struct nat_entry *natvec[NATVEC_SIZE];
1857         nid_t nid = 0;
1858         unsigned int found;
1859
1860         if (!nm_i)
1861                 return;
1862
1863         /* destroy free nid list */
1864         spin_lock(&nm_i->free_nid_list_lock);
1865         list_for_each_entry_safe(i, next_i, &nm_i->free_nid_list, list) {
1866                 f2fs_bug_on(i->state == NID_ALLOC);
1867                 __del_from_free_nid_list(nm_i, i);
1868                 nm_i->fcnt--;
1869         }
1870         f2fs_bug_on(nm_i->fcnt);
1871         spin_unlock(&nm_i->free_nid_list_lock);
1872
1873         /* destroy nat cache */
1874         write_lock(&nm_i->nat_tree_lock);
1875         while ((found = __gang_lookup_nat_cache(nm_i,
1876                                         nid, NATVEC_SIZE, natvec))) {
1877                 unsigned idx;
1878                 for (idx = 0; idx < found; idx++) {
1879                         struct nat_entry *e = natvec[idx];
1880                         nid = nat_get_nid(e) + 1;
1881                         __del_from_nat_cache(nm_i, e);
1882                 }
1883         }
1884         f2fs_bug_on(nm_i->nat_cnt);
1885         write_unlock(&nm_i->nat_tree_lock);
1886
1887         kfree(nm_i->nat_bitmap);
1888         sbi->nm_info = NULL;
1889         kfree(nm_i);
1890 }
1891
1892 int __init create_node_manager_caches(void)
1893 {
1894         nat_entry_slab = f2fs_kmem_cache_create("nat_entry",
1895                         sizeof(struct nat_entry), NULL);
1896         if (!nat_entry_slab)
1897                 return -ENOMEM;
1898
1899         free_nid_slab = f2fs_kmem_cache_create("free_nid",
1900                         sizeof(struct free_nid), NULL);
1901         if (!free_nid_slab) {
1902                 kmem_cache_destroy(nat_entry_slab);
1903                 return -ENOMEM;
1904         }
1905         return 0;
1906 }
1907
1908 void destroy_node_manager_caches(void)
1909 {
1910         kmem_cache_destroy(free_nid_slab);
1911         kmem_cache_destroy(nat_entry_slab);
1912 }