fs/btrfs/delayed-inode.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011 Fujitsu.  All rights reserved.
   4  * Written by Miao Xie <miaox@cn.fujitsu.com>
   5  */
   6
   7 #include <linux/slab.h>
   8 #include <linux/iversion.h>
   9 #include "misc.h"
  10 #include "delayed-inode.h"
  11 #include "disk-io.h"
  12 #include "transaction.h"
  13 #include "ctree.h"
  14 #include "qgroup.h"
  15 #include "locking.h"
  16
  17 #define BTRFS_DELAYED_WRITEBACK         512
  18 #define BTRFS_DELAYED_BACKGROUND        128
  19 #define BTRFS_DELAYED_BATCH             16
  20
  21 static struct kmem_cache *delayed_node_cache;
  22
  23 int __init btrfs_delayed_inode_init(void)
  24 {
  25         delayed_node_cache = kmem_cache_create("btrfs_delayed_node",
  26                                         sizeof(struct btrfs_delayed_node),
  27                                         0,
  28                                         SLAB_MEM_SPREAD,
  29                                         NULL);
  30         if (!delayed_node_cache)
  31                 return -ENOMEM;
  32         return 0;
  33 }
  34
  35 void __cold btrfs_delayed_inode_exit(void)
  36 {
  37         kmem_cache_destroy(delayed_node_cache);
  38 }
  39
  40 static inline void btrfs_init_delayed_node(
  41                                 struct btrfs_delayed_node *delayed_node,
  42                                 struct btrfs_root *root, u64 inode_id)
  43 {
  44         delayed_node->root = root;
  45         delayed_node->inode_id = inode_id;
  46         refcount_set(&delayed_node->refs, 0);
  47         delayed_node->ins_root = RB_ROOT_CACHED;
  48         delayed_node->del_root = RB_ROOT_CACHED;
  49         mutex_init(&delayed_node->mutex);
  50         INIT_LIST_HEAD(&delayed_node->n_list);
  51         INIT_LIST_HEAD(&delayed_node->p_list);
  52 }
  53
  54 static inline int btrfs_is_continuous_delayed_item(
  55                                         struct btrfs_delayed_item *item1,
  56                                         struct btrfs_delayed_item *item2)
  57 {
  58         if (item1->key.type == BTRFS_DIR_INDEX_KEY &&
  59             item1->key.objectid == item2->key.objectid &&
  60             item1->key.type == item2->key.type &&
  61             item1->key.offset + 1 == item2->key.offset)
  62                 return 1;
  63         return 0;
  64 }
  65
  66 static struct btrfs_delayed_node *btrfs_get_delayed_node(
  67                 struct btrfs_inode *btrfs_inode)
  68 {
  69         struct btrfs_root *root = btrfs_inode->root;
  70         u64 ino = btrfs_ino(btrfs_inode);
  71         struct btrfs_delayed_node *node;
  72
  73         node = READ_ONCE(btrfs_inode->delayed_node);
  74         if (node) {
  75                 refcount_inc(&node->refs);
  76                 return node;
  77         }
  78
  79         spin_lock(&root->inode_lock);
  80         node = radix_tree_lookup(&root->delayed_nodes_tree, ino);
  81
  82         if (node) {
  83                 if (btrfs_inode->delayed_node) {
  84                         refcount_inc(&node->refs);      /* can be accessed */
  85                         BUG_ON(btrfs_inode->delayed_node != node);
  86                         spin_unlock(&root->inode_lock);
  87                         return node;
  88                 }
  89
  90                 /*
  91                  * It's possible that we're racing into the middle of removing
  92                  * this node from the radix tree.  In this case, the refcount
  93                  * was zero and it should never go back to one.  Just return
  94                  * NULL like it was never in the radix at all; our release
  95                  * function is in the process of removing it.
  96                  *
  97                  * Some implementations of refcount_inc refuse to bump the
  98                  * refcount once it has hit zero.  If we don't do this dance
  99                  * here, refcount_inc() may decide to just WARN_ONCE() instead
 100                  * of actually bumping the refcount.
 101                  *
 102                  * If this node is properly in the radix, we want to bump the
 103                  * refcount twice, once for the inode and once for this get
 104                  * operation.
 105                  */
 106                 if (refcount_inc_not_zero(&node->refs)) {
 107                         refcount_inc(&node->refs);
 108                         btrfs_inode->delayed_node = node;
 109                 } else {
 110                         node = NULL;
 111                 }
 112
 113                 spin_unlock(&root->inode_lock);
 114                 return node;
 115         }
 116         spin_unlock(&root->inode_lock);
 117
 118         return NULL;
 119 }
 120
 121 /* Will return either the node or PTR_ERR(-ENOMEM) */
 122 static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
 123                 struct btrfs_inode *btrfs_inode)
 124 {
 125         struct btrfs_delayed_node *node;
 126         struct btrfs_root *root = btrfs_inode->root;
 127         u64 ino = btrfs_ino(btrfs_inode);
 128         int ret;
 129
 130 again:
 131         node = btrfs_get_delayed_node(btrfs_inode);
 132         if (node)
 133                 return node;
 134
 135         node = kmem_cache_zalloc(delayed_node_cache, GFP_NOFS);
 136         if (!node)
 137                 return ERR_PTR(-ENOMEM);
 138         btrfs_init_delayed_node(node, root, ino);
 139
 140         /* cached in the btrfs inode and can be accessed */
 141         refcount_set(&node->refs, 2);
 142
 143         ret = radix_tree_preload(GFP_NOFS);
 144         if (ret) {
 145                 kmem_cache_free(delayed_node_cache, node);
 146                 return ERR_PTR(ret);
 147         }
 148
 149         spin_lock(&root->inode_lock);
 150         ret = radix_tree_insert(&root->delayed_nodes_tree, ino, node);
 151         if (ret == -EEXIST) {
 152                 spin_unlock(&root->inode_lock);
 153                 kmem_cache_free(delayed_node_cache, node);
 154                 radix_tree_preload_end();
 155                 goto again;
 156         }
 157         btrfs_inode->delayed_node = node;
 158         spin_unlock(&root->inode_lock);
 159         radix_tree_preload_end();
 160
 161         return node;
 162 }
 163
 164 /*
 165  * Call it when holding delayed_node->mutex
 166  *
 167  * If mod = 1, add this node into the prepared list.
 168  */
 169 static void btrfs_queue_delayed_node(struct btrfs_delayed_root *root,
 170                                      struct btrfs_delayed_node *node,
 171                                      int mod)
 172 {
 173         spin_lock(&root->lock);
 174         if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 175                 if (!list_empty(&node->p_list))
 176                         list_move_tail(&node->p_list, &root->prepare_list);
 177                 else if (mod)
 178                         list_add_tail(&node->p_list, &root->prepare_list);
 179         } else {
 180                 list_add_tail(&node->n_list, &root->node_list);
 181                 list_add_tail(&node->p_list, &root->prepare_list);
 182                 refcount_inc(&node->refs);      /* inserted into list */
 183                 root->nodes++;
 184                 set_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 185         }
 186         spin_unlock(&root->lock);
 187 }
 188
 189 /* Call it when holding delayed_node->mutex */
 190 static void btrfs_dequeue_delayed_node(struct btrfs_delayed_root *root,
 191                                        struct btrfs_delayed_node *node)
 192 {
 193         spin_lock(&root->lock);
 194         if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 195                 root->nodes--;
 196                 refcount_dec(&node->refs);      /* not in the list */
 197                 list_del_init(&node->n_list);
 198                 if (!list_empty(&node->p_list))
 199                         list_del_init(&node->p_list);
 200                 clear_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 201         }
 202         spin_unlock(&root->lock);
 203 }
 204
 205 static struct btrfs_delayed_node *btrfs_first_delayed_node(
 206                         struct btrfs_delayed_root *delayed_root)
 207 {
 208         struct list_head *p;
 209         struct btrfs_delayed_node *node = NULL;
 210
 211         spin_lock(&delayed_root->lock);
 212         if (list_empty(&delayed_root->node_list))
 213                 goto out;
 214
 215         p = delayed_root->node_list.next;
 216         node = list_entry(p, struct btrfs_delayed_node, n_list);
 217         refcount_inc(&node->refs);
 218 out:
 219         spin_unlock(&delayed_root->lock);
 220
 221         return node;
 222 }
 223
 224 static struct btrfs_delayed_node *btrfs_next_delayed_node(
 225                                                 struct btrfs_delayed_node *node)
 226 {
 227         struct btrfs_delayed_root *delayed_root;
 228         struct list_head *p;
 229         struct btrfs_delayed_node *next = NULL;
 230
 231         delayed_root = node->root->fs_info->delayed_root;
 232         spin_lock(&delayed_root->lock);
 233         if (!test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 234                 /* not in the list */
 235                 if (list_empty(&delayed_root->node_list))
 236                         goto out;
 237                 p = delayed_root->node_list.next;
 238         } else if (list_is_last(&node->n_list, &delayed_root->node_list))
 239                 goto out;
 240         else
 241                 p = node->n_list.next;
 242
 243         next = list_entry(p, struct btrfs_delayed_node, n_list);
 244         refcount_inc(&next->refs);
 245 out:
 246         spin_unlock(&delayed_root->lock);
 247
 248         return next;
 249 }
 250
 251 static void __btrfs_release_delayed_node(
 252                                 struct btrfs_delayed_node *delayed_node,
 253                                 int mod)
 254 {
 255         struct btrfs_delayed_root *delayed_root;
 256
 257         if (!delayed_node)
 258                 return;
 259
 260         delayed_root = delayed_node->root->fs_info->delayed_root;
 261
 262         mutex_lock(&delayed_node->mutex);
 263         if (delayed_node->count)
 264                 btrfs_queue_delayed_node(delayed_root, delayed_node, mod);
 265         else
 266                 btrfs_dequeue_delayed_node(delayed_root, delayed_node);
 267         mutex_unlock(&delayed_node->mutex);
 268
 269         if (refcount_dec_and_test(&delayed_node->refs)) {
 270                 struct btrfs_root *root = delayed_node->root;
 271
 272                 spin_lock(&root->inode_lock);
 273                 /*
 274                  * Once our refcount goes to zero, nobody is allowed to bump it
 275                  * back up.  We can delete it now.
 276                  */
 277                 ASSERT(refcount_read(&delayed_node->refs) == 0);
 278                 radix_tree_delete(&root->delayed_nodes_tree,
 279                                   delayed_node->inode_id);
 280                 spin_unlock(&root->inode_lock);
 281                 kmem_cache_free(delayed_node_cache, delayed_node);
 282         }
 283 }
 284
 285 static inline void btrfs_release_delayed_node(struct btrfs_delayed_node *node)
 286 {
 287         __btrfs_release_delayed_node(node, 0);
 288 }
 289
 290 static struct btrfs_delayed_node *btrfs_first_prepared_delayed_node(
 291                                         struct btrfs_delayed_root *delayed_root)
 292 {
 293         struct list_head *p;
 294         struct btrfs_delayed_node *node = NULL;
 295
 296         spin_lock(&delayed_root->lock);
 297         if (list_empty(&delayed_root->prepare_list))
 298                 goto out;
 299
 300         p = delayed_root->prepare_list.next;
 301         list_del_init(p);
 302         node = list_entry(p, struct btrfs_delayed_node, p_list);
 303         refcount_inc(&node->refs);
 304 out:
 305         spin_unlock(&delayed_root->lock);
 306
 307         return node;
 308 }
 309
 310 static inline void btrfs_release_prepared_delayed_node(
 311                                         struct btrfs_delayed_node *node)
 312 {
 313         __btrfs_release_delayed_node(node, 1);
 314 }
 315
 316 static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u32 data_len)
 317 {
 318         struct btrfs_delayed_item *item;
 319         item = kmalloc(sizeof(*item) + data_len, GFP_NOFS);
 320         if (item) {
 321                 item->data_len = data_len;
 322                 item->ins_or_del = 0;
 323                 item->bytes_reserved = 0;
 324                 item->delayed_node = NULL;
 325                 refcount_set(&item->refs, 1);
 326         }
 327         return item;
 328 }
 329
 330 /*
 331  * __btrfs_lookup_delayed_item - look up the delayed item by key
 332  * @delayed_node: pointer to the delayed node
 333  * @key:          the key to look up
 334  * @prev:         used to store the prev item if the right item isn't found
 335  * @next:         used to store the next item if the right item isn't found
 336  *
 337  * Note: if we don't find the right item, we will return the prev item and
 338  * the next item.
 339  */
 340 static struct btrfs_delayed_item *__btrfs_lookup_delayed_item(
 341                                 struct rb_root *root,
 342                                 struct btrfs_key *key,
 343                                 struct btrfs_delayed_item **prev,
 344                                 struct btrfs_delayed_item **next)
 345 {
 346         struct rb_node *node, *prev_node = NULL;
 347         struct btrfs_delayed_item *delayed_item = NULL;
 348         int ret = 0;
 349
 350         node = root->rb_node;
 351
 352         while (node) {
 353                 delayed_item = rb_entry(node, struct btrfs_delayed_item,
 354                                         rb_node);
 355                 prev_node = node;
 356                 ret = btrfs_comp_cpu_keys(&delayed_item->key, key);
 357                 if (ret < 0)
 358                         node = node->rb_right;
 359                 else if (ret > 0)
 360                         node = node->rb_left;
 361                 else
 362                         return delayed_item;
 363         }
 364
 365         if (prev) {
 366                 if (!prev_node)
 367                         *prev = NULL;
 368                 else if (ret < 0)
 369                         *prev = delayed_item;
 370                 else if ((node = rb_prev(prev_node)) != NULL) {
 371                         *prev = rb_entry(node, struct btrfs_delayed_item,
 372                                          rb_node);
 373                 } else
 374                         *prev = NULL;
 375         }
 376
 377         if (next) {
 378                 if (!prev_node)
 379                         *next = NULL;
 380                 else if (ret > 0)
 381                         *next = delayed_item;
 382                 else if ((node = rb_next(prev_node)) != NULL) {
 383                         *next = rb_entry(node, struct btrfs_delayed_item,
 384                                          rb_node);
 385                 } else
 386                         *next = NULL;
 387         }
 388         return NULL;
 389 }
 390
 391 static struct btrfs_delayed_item *__btrfs_lookup_delayed_insertion_item(
 392                                         struct btrfs_delayed_node *delayed_node,
 393                                         struct btrfs_key *key)
 394 {
 395         return __btrfs_lookup_delayed_item(&delayed_node->ins_root.rb_root, key,
 396                                            NULL, NULL);
 397 }
 398
 399 static int __btrfs_add_delayed_item(struct btrfs_delayed_node *delayed_node,
 400                                     struct btrfs_delayed_item *ins,
 401                                     int action)
 402 {
 403         struct rb_node **p, *node;
 404         struct rb_node *parent_node = NULL;
 405         struct rb_root_cached *root;
 406         struct btrfs_delayed_item *item;
 407         int cmp;
 408         bool leftmost = true;
 409
 410         if (action == BTRFS_DELAYED_INSERTION_ITEM)
 411                 root = &delayed_node->ins_root;
 412         else if (action == BTRFS_DELAYED_DELETION_ITEM)
 413                 root = &delayed_node->del_root;
 414         else
 415                 BUG();
 416         p = &root->rb_root.rb_node;
 417         node = &ins->rb_node;
 418
 419         while (*p) {
 420                 parent_node = *p;
 421                 item = rb_entry(parent_node, struct btrfs_delayed_item,
 422                                  rb_node);
 423
 424                 cmp = btrfs_comp_cpu_keys(&item->key, &ins->key);
 425                 if (cmp < 0) {
 426                         p = &(*p)->rb_right;
 427                         leftmost = false;
 428                 } else if (cmp > 0) {
 429                         p = &(*p)->rb_left;
 430                 } else {
 431                         return -EEXIST;
 432                 }
 433         }
 434
 435         rb_link_node(node, parent_node, p);
 436         rb_insert_color_cached(node, root, leftmost);
 437         ins->delayed_node = delayed_node;
 438         ins->ins_or_del = action;
 439
 440         if (ins->key.type == BTRFS_DIR_INDEX_KEY &&
 441             action == BTRFS_DELAYED_INSERTION_ITEM &&
 442             ins->key.offset >= delayed_node->index_cnt)
 443                         delayed_node->index_cnt = ins->key.offset + 1;
 444
 445         delayed_node->count++;
 446         atomic_inc(&delayed_node->root->fs_info->delayed_root->items);
 447         return 0;
 448 }
 449
 450 static int __btrfs_add_delayed_insertion_item(struct btrfs_delayed_node *node,
 451                                               struct btrfs_delayed_item *item)
 452 {
 453         return __btrfs_add_delayed_item(node, item,
 454                                         BTRFS_DELAYED_INSERTION_ITEM);
 455 }
 456
 457 static int __btrfs_add_delayed_deletion_item(struct btrfs_delayed_node *node,
 458                                              struct btrfs_delayed_item *item)
 459 {
 460         return __btrfs_add_delayed_item(node, item,
 461                                         BTRFS_DELAYED_DELETION_ITEM);
 462 }
 463
 464 static void finish_one_item(struct btrfs_delayed_root *delayed_root)
 465 {
 466         int seq = atomic_inc_return(&delayed_root->items_seq);
 467
 468         /* atomic_dec_return implies a barrier */
 469         if ((atomic_dec_return(&delayed_root->items) <
 470             BTRFS_DELAYED_BACKGROUND || seq % BTRFS_DELAYED_BATCH == 0))
 471                 cond_wake_up_nomb(&delayed_root->wait);
 472 }
 473
 474 static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item)
 475 {
 476         struct rb_root_cached *root;
 477         struct btrfs_delayed_root *delayed_root;
 478
 479         /* Not associated with any delayed_node */
 480         if (!delayed_item->delayed_node)
 481                 return;
 482         delayed_root = delayed_item->delayed_node->root->fs_info->delayed_root;
 483
 484         BUG_ON(!delayed_root);
 485         BUG_ON(delayed_item->ins_or_del != BTRFS_DELAYED_DELETION_ITEM &&
 486                delayed_item->ins_or_del != BTRFS_DELAYED_INSERTION_ITEM);
 487
 488         if (delayed_item->ins_or_del == BTRFS_DELAYED_INSERTION_ITEM)
 489                 root = &delayed_item->delayed_node->ins_root;
 490         else
 491                 root = &delayed_item->delayed_node->del_root;
 492
 493         rb_erase_cached(&delayed_item->rb_node, root);
 494         delayed_item->delayed_node->count--;
 495
 496         finish_one_item(delayed_root);
 497 }
 498
 499 static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
 500 {
 501         if (item) {
 502                 __btrfs_remove_delayed_item(item);
 503                 if (refcount_dec_and_test(&item->refs))
 504                         kfree(item);
 505         }
 506 }
 507
 508 static struct btrfs_delayed_item *__btrfs_first_delayed_insertion_item(
 509                                         struct btrfs_delayed_node *delayed_node)
 510 {
 511         struct rb_node *p;
 512         struct btrfs_delayed_item *item = NULL;
 513
 514         p = rb_first_cached(&delayed_node->ins_root);
 515         if (p)
 516                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 517
 518         return item;
 519 }
 520
 521 static struct btrfs_delayed_item *__btrfs_first_delayed_deletion_item(
 522                                         struct btrfs_delayed_node *delayed_node)
 523 {
 524         struct rb_node *p;
 525         struct btrfs_delayed_item *item = NULL;
 526
 527         p = rb_first_cached(&delayed_node->del_root);
 528         if (p)
 529                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 530
 531         return item;
 532 }
 533
 534 static struct btrfs_delayed_item *__btrfs_next_delayed_item(
 535                                                 struct btrfs_delayed_item *item)
 536 {
 537         struct rb_node *p;
 538         struct btrfs_delayed_item *next = NULL;
 539
 540         p = rb_next(&item->rb_node);
 541         if (p)
 542                 next = rb_entry(p, struct btrfs_delayed_item, rb_node);
 543
 544         return next;
 545 }
 546
 547 static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
 548                                                struct btrfs_root *root,
 549                                                struct btrfs_delayed_item *item)
 550 {
 551         struct btrfs_block_rsv *src_rsv;
 552         struct btrfs_block_rsv *dst_rsv;
 553         struct btrfs_fs_info *fs_info = root->fs_info;
 554         u64 num_bytes;
 555         int ret;
 556
 557         if (!trans->bytes_reserved)
 558                 return 0;
 559
 560         src_rsv = trans->block_rsv;
 561         dst_rsv = &fs_info->delayed_block_rsv;
 562
 563         num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
 564
 565         /*
 566          * Here we migrate space rsv from transaction rsv, since have already
 567          * reserved space when starting a transaction.  So no need to reserve
 568          * qgroup space here.
 569          */
 570         ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 571         if (!ret) {
 572                 trace_btrfs_space_reservation(fs_info, "delayed_item",
 573                                               item->key.objectid,
 574                                               num_bytes, 1);
 575                 item->bytes_reserved = num_bytes;
 576         }
 577
 578         return ret;
 579 }
 580
 581 static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
 582                                                 struct btrfs_delayed_item *item)
 583 {
 584         struct btrfs_block_rsv *rsv;
 585         struct btrfs_fs_info *fs_info = root->fs_info;
 586
 587         if (!item->bytes_reserved)
 588                 return;
 589
 590         rsv = &fs_info->delayed_block_rsv;
 591         /*
 592          * Check btrfs_delayed_item_reserve_metadata() to see why we don't need
 593          * to release/reserve qgroup space.
 594          */
 595         trace_btrfs_space_reservation(fs_info, "delayed_item",
 596                                       item->key.objectid, item->bytes_reserved,
 597                                       0);
 598         btrfs_block_rsv_release(fs_info, rsv, item->bytes_reserved, NULL);
 599 }
 600
 601 static int btrfs_delayed_inode_reserve_metadata(
 602                                         struct btrfs_trans_handle *trans,
 603                                         struct btrfs_root *root,
 604                                         struct btrfs_delayed_node *node)
 605 {
 606         struct btrfs_fs_info *fs_info = root->fs_info;
 607         struct btrfs_block_rsv *src_rsv;
 608         struct btrfs_block_rsv *dst_rsv;
 609         u64 num_bytes;
 610         int ret;
 611
 612         src_rsv = trans->block_rsv;
 613         dst_rsv = &fs_info->delayed_block_rsv;
 614
 615         num_bytes = btrfs_calc_metadata_size(fs_info, 1);
 616
 617         /*
 618          * btrfs_dirty_inode will update the inode under btrfs_join_transaction
 619          * which doesn't reserve space for speed.  This is a problem since we
 620          * still need to reserve space for this update, so try to reserve the
 621          * space.
 622          *
 623          * Now if src_rsv == delalloc_block_rsv we'll let it just steal since
 624          * we always reserve enough to update the inode item.
 625          */
 626         if (!src_rsv || (!trans->bytes_reserved &&
 627                          src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) {
 628                 ret = btrfs_qgroup_reserve_meta(root, num_bytes,
 629                                           BTRFS_QGROUP_RSV_META_PREALLOC, true);
 630                 if (ret < 0)
 631                         return ret;
 632                 ret = btrfs_block_rsv_add(root, dst_rsv, num_bytes,
 633                                           BTRFS_RESERVE_NO_FLUSH);
 634                 /* NO_FLUSH could only fail with -ENOSPC */
 635                 ASSERT(ret == 0 || ret == -ENOSPC);
 636                 if (ret)
 637                         btrfs_qgroup_free_meta_prealloc(root, num_bytes);
 638         } else {
 639                 ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 640         }
 641
 642         if (!ret) {
 643                 trace_btrfs_space_reservation(fs_info, "delayed_inode",
 644                                               node->inode_id, num_bytes, 1);
 645                 node->bytes_reserved = num_bytes;
 646         }
 647
 648         return ret;
 649 }
 650
 651 static void btrfs_delayed_inode_release_metadata(struct btrfs_fs_info *fs_info,
 652                                                 struct btrfs_delayed_node *node,
 653                                                 bool qgroup_free)
 654 {
 655         struct btrfs_block_rsv *rsv;
 656
 657         if (!node->bytes_reserved)
 658                 return;
 659
 660         rsv = &fs_info->delayed_block_rsv;
 661         trace_btrfs_space_reservation(fs_info, "delayed_inode",
 662                                       node->inode_id, node->bytes_reserved, 0);
 663         btrfs_block_rsv_release(fs_info, rsv, node->bytes_reserved, NULL);
 664         if (qgroup_free)
 665                 btrfs_qgroup_free_meta_prealloc(node->root,
 666                                 node->bytes_reserved);
 667         else
 668                 btrfs_qgroup_convert_reserved_meta(node->root,
 669                                 node->bytes_reserved);
 670         node->bytes_reserved = 0;
 671 }
 672
 673 /*
 674  * Insert a single delayed item or a batch of delayed items that have consecutive
 675  * keys if they exist.
 676  */
 677 static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 678                                      struct btrfs_root *root,
 679                                      struct btrfs_path *path,
 680                                      struct btrfs_delayed_item *first_item)
 681 {
 682         LIST_HEAD(item_list);
 683         struct btrfs_delayed_item *curr;
 684         struct btrfs_delayed_item *next;
 685         const int max_size = BTRFS_LEAF_DATA_SIZE(root->fs_info);
 686         struct btrfs_item_batch batch;
 687         int total_size;
 688         char *ins_data = NULL;
 689         int ret;
 690
 691         list_add_tail(&first_item->tree_list, &item_list);
 692         batch.total_data_size = first_item->data_len;
 693         batch.nr = 1;
 694         total_size = first_item->data_len + sizeof(struct btrfs_item);
 695         curr = first_item;
 696
 697         while (true) {
 698                 int next_size;
 699
 700                 next = __btrfs_next_delayed_item(curr);
 701                 if (!next || !btrfs_is_continuous_delayed_item(curr, next))
 702                         break;
 703
 704                 next_size = next->data_len + sizeof(struct btrfs_item);
 705                 if (total_size + next_size > max_size)
 706                         break;
 707
 708                 list_add_tail(&next->tree_list, &item_list);
 709                 batch.nr++;
 710                 total_size += next_size;
 711                 batch.total_data_size += next->data_len;
 712                 curr = next;
 713         }
 714
 715         if (batch.nr == 1) {
 716                 batch.keys = &first_item->key;
 717                 batch.data_sizes = &first_item->data_len;
 718         } else {
 719                 struct btrfs_key *ins_keys;
 720                 u32 *ins_sizes;
 721                 int i = 0;
 722
 723                 ins_data = kmalloc(batch.nr * sizeof(u32) +
 724                                    batch.nr * sizeof(struct btrfs_key), GFP_NOFS);
 725                 if (!ins_data) {
 726                         ret = -ENOMEM;
 727                         goto out;
 728                 }
 729                 ins_sizes = (u32 *)ins_data;
 730                 ins_keys = (struct btrfs_key *)(ins_data + batch.nr * sizeof(u32));
 731                 batch.keys = ins_keys;
 732                 batch.data_sizes = ins_sizes;
 733                 list_for_each_entry(curr, &item_list, tree_list) {
 734                         ins_keys[i] = curr->key;
 735                         ins_sizes[i] = curr->data_len;
 736                         i++;
 737                 }
 738         }
 739
 740         ret = btrfs_insert_empty_items(trans, root, path, &batch);
 741         if (ret)
 742                 goto out;
 743
 744         list_for_each_entry(curr, &item_list, tree_list) {
 745                 char *data_ptr;
 746
 747                 data_ptr = btrfs_item_ptr(path->nodes[0], path->slots[0], char);
 748                 write_extent_buffer(path->nodes[0], &curr->data,
 749                                     (unsigned long)data_ptr, curr->data_len);
 750                 path->slots[0]++;
 751         }
 752
 753         /*
 754          * Now release our path before releasing the delayed items and their
 755          * metadata reservations, so that we don't block other tasks for more
 756          * time than needed.
 757          */
 758         btrfs_release_path(path);
 759
 760         list_for_each_entry_safe(curr, next, &item_list, tree_list) {
 761                 list_del(&curr->tree_list);
 762                 btrfs_delayed_item_release_metadata(root, curr);
 763                 btrfs_release_delayed_item(curr);
 764         }
 765 out:
 766         kfree(ins_data);
 767         return ret;
 768 }
 769
 770 static int btrfs_insert_delayed_items(struct btrfs_trans_handle *trans,
 771                                       struct btrfs_path *path,
 772                                       struct btrfs_root *root,
 773                                       struct btrfs_delayed_node *node)
 774 {
 775         int ret = 0;
 776
 777         while (ret == 0) {
 778                 struct btrfs_delayed_item *curr;
 779
 780                 mutex_lock(&node->mutex);
 781                 curr = __btrfs_first_delayed_insertion_item(node);
 782                 if (!curr) {
 783                         mutex_unlock(&node->mutex);
 784                         break;
 785                 }
 786                 ret = btrfs_insert_delayed_item(trans, root, path, curr);
 787                 mutex_unlock(&node->mutex);
 788         }
 789
 790         return ret;
 791 }
 792
 793 static int btrfs_batch_delete_items(struct btrfs_trans_handle *trans,
 794                                     struct btrfs_root *root,
 795                                     struct btrfs_path *path,
 796                                     struct btrfs_delayed_item *item)
 797 {
 798         struct btrfs_delayed_item *curr, *next;
 799         struct extent_buffer *leaf;
 800         struct btrfs_key key;
 801         struct list_head head;
 802         int nitems, i, last_item;
 803         int ret = 0;
 804
 805         BUG_ON(!path->nodes[0]);
 806
 807         leaf = path->nodes[0];
 808
 809         i = path->slots[0];
 810         last_item = btrfs_header_nritems(leaf) - 1;
 811         if (i > last_item)
 812                 return -ENOENT; /* FIXME: Is errno suitable? */
 813
 814         next = item;
 815         INIT_LIST_HEAD(&head);
 816         btrfs_item_key_to_cpu(leaf, &key, i);
 817         nitems = 0;
 818         /*
 819          * count the number of the dir index items that we can delete in batch
 820          */
 821         while (btrfs_comp_cpu_keys(&next->key, &key) == 0) {
 822                 list_add_tail(&next->tree_list, &head);
 823                 nitems++;
 824
 825                 curr = next;
 826                 next = __btrfs_next_delayed_item(curr);
 827                 if (!next)
 828                         break;
 829
 830                 if (!btrfs_is_continuous_delayed_item(curr, next))
 831                         break;
 832
 833                 i++;
 834                 if (i > last_item)
 835                         break;
 836                 btrfs_item_key_to_cpu(leaf, &key, i);
 837         }
 838
 839         if (!nitems)
 840                 return 0;
 841
 842         ret = btrfs_del_items(trans, root, path, path->slots[0], nitems);
 843         if (ret)
 844                 goto out;
 845
 846         list_for_each_entry_safe(curr, next, &head, tree_list) {
 847                 btrfs_delayed_item_release_metadata(root, curr);
 848                 list_del(&curr->tree_list);
 849                 btrfs_release_delayed_item(curr);
 850         }
 851
 852 out:
 853         return ret;
 854 }
 855
 856 static int btrfs_delete_delayed_items(struct btrfs_trans_handle *trans,
 857                                       struct btrfs_path *path,
 858                                       struct btrfs_root *root,
 859                                       struct btrfs_delayed_node *node)
 860 {
 861         struct btrfs_delayed_item *curr, *prev;
 862         int ret = 0;
 863
 864 do_again:
 865         mutex_lock(&node->mutex);
 866         curr = __btrfs_first_delayed_deletion_item(node);
 867         if (!curr)
 868                 goto delete_fail;
 869
 870         ret = btrfs_search_slot(trans, root, &curr->key, path, -1, 1);
 871         if (ret < 0)
 872                 goto delete_fail;
 873         else if (ret > 0) {
 874                 /*
 875                  * can't find the item which the node points to, so this node
 876                  * is invalid, just drop it.
 877                  */
 878                 prev = curr;
 879                 curr = __btrfs_next_delayed_item(prev);
 880                 btrfs_release_delayed_item(prev);
 881                 ret = 0;
 882                 btrfs_release_path(path);
 883                 if (curr) {
 884                         mutex_unlock(&node->mutex);
 885                         goto do_again;
 886                 } else
 887                         goto delete_fail;
 888         }
 889
 890         btrfs_batch_delete_items(trans, root, path, curr);
 891         btrfs_release_path(path);
 892         mutex_unlock(&node->mutex);
 893         goto do_again;
 894
 895 delete_fail:
 896         btrfs_release_path(path);
 897         mutex_unlock(&node->mutex);
 898         return ret;
 899 }
 900
 901 static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
 902 {
 903         struct btrfs_delayed_root *delayed_root;
 904
 905         if (delayed_node &&
 906             test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
 907                 BUG_ON(!delayed_node->root);
 908                 clear_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
 909                 delayed_node->count--;
 910
 911                 delayed_root = delayed_node->root->fs_info->delayed_root;
 912                 finish_one_item(delayed_root);
 913         }
 914 }
 915
 916 static void btrfs_release_delayed_iref(struct btrfs_delayed_node *delayed_node)
 917 {
 918
 919         if (test_and_clear_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags)) {
 920                 struct btrfs_delayed_root *delayed_root;
 921
 922                 ASSERT(delayed_node->root);
 923                 delayed_node->count--;
 924
 925                 delayed_root = delayed_node->root->fs_info->delayed_root;
 926                 finish_one_item(delayed_root);
 927         }
 928 }
 929
 930 static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
 931                                         struct btrfs_root *root,
 932                                         struct btrfs_path *path,
 933                                         struct btrfs_delayed_node *node)
 934 {
 935         struct btrfs_fs_info *fs_info = root->fs_info;
 936         struct btrfs_key key;
 937         struct btrfs_inode_item *inode_item;
 938         struct extent_buffer *leaf;
 939         int mod;
 940         int ret;
 941
 942         key.objectid = node->inode_id;
 943         key.type = BTRFS_INODE_ITEM_KEY;
 944         key.offset = 0;
 945
 946         if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
 947                 mod = -1;
 948         else
 949                 mod = 1;
 950
 951         ret = btrfs_lookup_inode(trans, root, path, &key, mod);
 952         if (ret > 0)
 953                 ret = -ENOENT;
 954         if (ret < 0)
 955                 goto out;
 956
 957         leaf = path->nodes[0];
 958         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 959                                     struct btrfs_inode_item);
 960         write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
 961                             sizeof(struct btrfs_inode_item));
 962         btrfs_mark_buffer_dirty(leaf);
 963
 964         if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
 965                 goto out;
 966
 967         path->slots[0]++;
 968         if (path->slots[0] >= btrfs_header_nritems(leaf))
 969                 goto search;
 970 again:
 971         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 972         if (key.objectid != node->inode_id)
 973                 goto out;
 974
 975         if (key.type != BTRFS_INODE_REF_KEY &&
 976             key.type != BTRFS_INODE_EXTREF_KEY)
 977                 goto out;
 978
 979         /*
 980          * Delayed iref deletion is for the inode who has only one link,
 981          * so there is only one iref. The case that several irefs are
 982          * in the same item doesn't exist.
 983          */
 984         btrfs_del_item(trans, root, path);
 985 out:
 986         btrfs_release_delayed_iref(node);
 987         btrfs_release_path(path);
 988 err_out:
 989         btrfs_delayed_inode_release_metadata(fs_info, node, (ret < 0));
 990         btrfs_release_delayed_inode(node);
 991
 992         /*
 993          * If we fail to update the delayed inode we need to abort the
 994          * transaction, because we could leave the inode with the improper
 995          * counts behind.
 996          */
 997         if (ret && ret != -ENOENT)
 998                 btrfs_abort_transaction(trans, ret);
 999
1000         return ret;
1001
1002 search:
1003         btrfs_release_path(path);
1004
1005         key.type = BTRFS_INODE_EXTREF_KEY;
1006         key.offset = -1;
1007
1008         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1009         if (ret < 0)
1010                 goto err_out;
1011         ASSERT(ret);
1012
1013         ret = 0;
1014         leaf = path->nodes[0];
1015         path->slots[0]--;
1016         goto again;
1017 }
1018
1019 static inline int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
1020                                              struct btrfs_root *root,
1021                                              struct btrfs_path *path,
1022                                              struct btrfs_delayed_node *node)
1023 {
1024         int ret;
1025
1026         mutex_lock(&node->mutex);
1027         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &node->flags)) {
1028                 mutex_unlock(&node->mutex);
1029                 return 0;
1030         }
1031
1032         ret = __btrfs_update_delayed_inode(trans, root, path, node);
1033         mutex_unlock(&node->mutex);
1034         return ret;
1035 }
1036
1037 static inline int
1038 __btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1039                                    struct btrfs_path *path,
1040                                    struct btrfs_delayed_node *node)
1041 {
1042         int ret;
1043
1044         ret = btrfs_insert_delayed_items(trans, path, node->root, node);
1045         if (ret)
1046                 return ret;
1047
1048         ret = btrfs_delete_delayed_items(trans, path, node->root, node);
1049         if (ret)
1050                 return ret;
1051
1052         ret = btrfs_update_delayed_inode(trans, node->root, path, node);
1053         return ret;
1054 }
1055
1056 /*
1057  * Called when committing the transaction.
1058  * Returns 0 on success.
1059  * Returns < 0 on error and returns with an aborted transaction with any
1060  * outstanding delayed items cleaned up.
1061  */
1062 static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
1063 {
1064         struct btrfs_fs_info *fs_info = trans->fs_info;
1065         struct btrfs_delayed_root *delayed_root;
1066         struct btrfs_delayed_node *curr_node, *prev_node;
1067         struct btrfs_path *path;
1068         struct btrfs_block_rsv *block_rsv;
1069         int ret = 0;
1070         bool count = (nr > 0);
1071
1072         if (TRANS_ABORTED(trans))
1073                 return -EIO;
1074
1075         path = btrfs_alloc_path();
1076         if (!path)
1077                 return -ENOMEM;
1078
1079         block_rsv = trans->block_rsv;
1080         trans->block_rsv = &fs_info->delayed_block_rsv;
1081
1082         delayed_root = fs_info->delayed_root;
1083
1084         curr_node = btrfs_first_delayed_node(delayed_root);
1085         while (curr_node && (!count || nr--)) {
1086                 ret = __btrfs_commit_inode_delayed_items(trans, path,
1087                                                          curr_node);
1088                 if (ret) {
1089                         btrfs_release_delayed_node(curr_node);
1090                         curr_node = NULL;
1091                         btrfs_abort_transaction(trans, ret);
1092                         break;
1093                 }
1094
1095                 prev_node = curr_node;
1096                 curr_node = btrfs_next_delayed_node(curr_node);
1097                 btrfs_release_delayed_node(prev_node);
1098         }
1099
1100         if (curr_node)
1101                 btrfs_release_delayed_node(curr_node);
1102         btrfs_free_path(path);
1103         trans->block_rsv = block_rsv;
1104
1105         return ret;
1106 }
1107
1108 int btrfs_run_delayed_items(struct btrfs_trans_handle *trans)
1109 {
1110         return __btrfs_run_delayed_items(trans, -1);
1111 }
1112
1113 int btrfs_run_delayed_items_nr(struct btrfs_trans_handle *trans, int nr)
1114 {
1115         return __btrfs_run_delayed_items(trans, nr);
1116 }
1117
1118 int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1119                                      struct btrfs_inode *inode)
1120 {
1121         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1122         struct btrfs_path *path;
1123         struct btrfs_block_rsv *block_rsv;
1124         int ret;
1125
1126         if (!delayed_node)
1127                 return 0;
1128
1129         mutex_lock(&delayed_node->mutex);
1130         if (!delayed_node->count) {
1131                 mutex_unlock(&delayed_node->mutex);
1132                 btrfs_release_delayed_node(delayed_node);
1133                 return 0;
1134         }
1135         mutex_unlock(&delayed_node->mutex);
1136
1137         path = btrfs_alloc_path();
1138         if (!path) {
1139                 btrfs_release_delayed_node(delayed_node);
1140                 return -ENOMEM;
1141         }
1142
1143         block_rsv = trans->block_rsv;
1144         trans->block_rsv = &delayed_node->root->fs_info->delayed_block_rsv;
1145
1146         ret = __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1147
1148         btrfs_release_delayed_node(delayed_node);
1149         btrfs_free_path(path);
1150         trans->block_rsv = block_rsv;
1151
1152         return ret;
1153 }
1154
1155 int btrfs_commit_inode_delayed_inode(struct btrfs_inode *inode)
1156 {
1157         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1158         struct btrfs_trans_handle *trans;
1159         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1160         struct btrfs_path *path;
1161         struct btrfs_block_rsv *block_rsv;
1162         int ret;
1163
1164         if (!delayed_node)
1165                 return 0;
1166
1167         mutex_lock(&delayed_node->mutex);
1168         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1169                 mutex_unlock(&delayed_node->mutex);
1170                 btrfs_release_delayed_node(delayed_node);
1171                 return 0;
1172         }
1173         mutex_unlock(&delayed_node->mutex);
1174
1175         trans = btrfs_join_transaction(delayed_node->root);
1176         if (IS_ERR(trans)) {
1177                 ret = PTR_ERR(trans);
1178                 goto out;
1179         }
1180
1181         path = btrfs_alloc_path();
1182         if (!path) {
1183                 ret = -ENOMEM;
1184                 goto trans_out;
1185         }
1186
1187         block_rsv = trans->block_rsv;
1188         trans->block_rsv = &fs_info->delayed_block_rsv;
1189
1190         mutex_lock(&delayed_node->mutex);
1191         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags))
1192                 ret = __btrfs_update_delayed_inode(trans, delayed_node->root,
1193                                                    path, delayed_node);
1194         else
1195                 ret = 0;
1196         mutex_unlock(&delayed_node->mutex);
1197
1198         btrfs_free_path(path);
1199         trans->block_rsv = block_rsv;
1200 trans_out:
1201         btrfs_end_transaction(trans);
1202         btrfs_btree_balance_dirty(fs_info);
1203 out:
1204         btrfs_release_delayed_node(delayed_node);
1205
1206         return ret;
1207 }
1208
1209 void btrfs_remove_delayed_node(struct btrfs_inode *inode)
1210 {
1211         struct btrfs_delayed_node *delayed_node;
1212
1213         delayed_node = READ_ONCE(inode->delayed_node);
1214         if (!delayed_node)
1215                 return;
1216
1217         inode->delayed_node = NULL;
1218         btrfs_release_delayed_node(delayed_node);
1219 }
1220
1221 struct btrfs_async_delayed_work {
1222         struct btrfs_delayed_root *delayed_root;
1223         int nr;
1224         struct btrfs_work work;
1225 };
1226
1227 static void btrfs_async_run_delayed_root(struct btrfs_work *work)
1228 {
1229         struct btrfs_async_delayed_work *async_work;
1230         struct btrfs_delayed_root *delayed_root;
1231         struct btrfs_trans_handle *trans;
1232         struct btrfs_path *path;
1233         struct btrfs_delayed_node *delayed_node = NULL;
1234         struct btrfs_root *root;
1235         struct btrfs_block_rsv *block_rsv;
1236         int total_done = 0;
1237
1238         async_work = container_of(work, struct btrfs_async_delayed_work, work);
1239         delayed_root = async_work->delayed_root;
1240
1241         path = btrfs_alloc_path();
1242         if (!path)
1243                 goto out;
1244
1245         do {
1246                 if (atomic_read(&delayed_root->items) <
1247                     BTRFS_DELAYED_BACKGROUND / 2)
1248                         break;
1249
1250                 delayed_node = btrfs_first_prepared_delayed_node(delayed_root);
1251                 if (!delayed_node)
1252                         break;
1253
1254                 root = delayed_node->root;
1255
1256                 trans = btrfs_join_transaction(root);
1257                 if (IS_ERR(trans)) {
1258                         btrfs_release_path(path);
1259                         btrfs_release_prepared_delayed_node(delayed_node);
1260                         total_done++;
1261                         continue;
1262                 }
1263
1264                 block_rsv = trans->block_rsv;
1265                 trans->block_rsv = &root->fs_info->delayed_block_rsv;
1266
1267                 __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1268
1269                 trans->block_rsv = block_rsv;
1270                 btrfs_end_transaction(trans);
1271                 btrfs_btree_balance_dirty_nodelay(root->fs_info);
1272
1273                 btrfs_release_path(path);
1274                 btrfs_release_prepared_delayed_node(delayed_node);
1275                 total_done++;
1276
1277         } while ((async_work->nr == 0 && total_done < BTRFS_DELAYED_WRITEBACK)
1278                  || total_done < async_work->nr);
1279
1280         btrfs_free_path(path);
1281 out:
1282         wake_up(&delayed_root->wait);
1283         kfree(async_work);
1284 }
1285
1286
1287 static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
1288                                      struct btrfs_fs_info *fs_info, int nr)
1289 {
1290         struct btrfs_async_delayed_work *async_work;
1291
1292         async_work = kmalloc(sizeof(*async_work), GFP_NOFS);
1293         if (!async_work)
1294                 return -ENOMEM;
1295
1296         async_work->delayed_root = delayed_root;
1297         btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root, NULL,
1298                         NULL);
1299         async_work->nr = nr;
1300
1301         btrfs_queue_work(fs_info->delayed_workers, &async_work->work);
1302         return 0;
1303 }
1304
1305 void btrfs_assert_delayed_root_empty(struct btrfs_fs_info *fs_info)
1306 {
1307         WARN_ON(btrfs_first_delayed_node(fs_info->delayed_root));
1308 }
1309
1310 static int could_end_wait(struct btrfs_delayed_root *delayed_root, int seq)
1311 {
1312         int val = atomic_read(&delayed_root->items_seq);
1313
1314         if (val < seq || val >= seq + BTRFS_DELAYED_BATCH)
1315                 return 1;
1316
1317         if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
1318                 return 1;
1319
1320         return 0;
1321 }
1322
1323 void btrfs_balance_delayed_items(struct btrfs_fs_info *fs_info)
1324 {
1325         struct btrfs_delayed_root *delayed_root = fs_info->delayed_root;
1326
1327         if ((atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND) ||
1328                 btrfs_workqueue_normal_congested(fs_info->delayed_workers))
1329                 return;
1330
1331         if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
1332                 int seq;
1333                 int ret;
1334
1335                 seq = atomic_read(&delayed_root->items_seq);
1336
1337                 ret = btrfs_wq_run_delayed_node(delayed_root, fs_info, 0);
1338                 if (ret)
1339                         return;
1340
1341                 wait_event_interruptible(delayed_root->wait,
1342                                          could_end_wait(delayed_root, seq));
1343                 return;
1344         }
1345
1346         btrfs_wq_run_delayed_node(delayed_root, fs_info, BTRFS_DELAYED_BATCH);
1347 }
1348
1349 /* Will return 0 or -ENOMEM */
1350 int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
1351                                    const char *name, int name_len,
1352                                    struct btrfs_inode *dir,
1353                                    struct btrfs_disk_key *disk_key, u8 type,
1354                                    u64 index)
1355 {
1356         struct btrfs_delayed_node *delayed_node;
1357         struct btrfs_delayed_item *delayed_item;
1358         struct btrfs_dir_item *dir_item;
1359         int ret;
1360
1361         delayed_node = btrfs_get_or_create_delayed_node(dir);
1362         if (IS_ERR(delayed_node))
1363                 return PTR_ERR(delayed_node);
1364
1365         delayed_item = btrfs_alloc_delayed_item(sizeof(*dir_item) + name_len);
1366         if (!delayed_item) {
1367                 ret = -ENOMEM;
1368                 goto release_node;
1369         }
1370
1371         delayed_item->key.objectid = btrfs_ino(dir);
1372         delayed_item->key.type = BTRFS_DIR_INDEX_KEY;
1373         delayed_item->key.offset = index;
1374
1375         dir_item = (struct btrfs_dir_item *)delayed_item->data;
1376         dir_item->location = *disk_key;
1377         btrfs_set_stack_dir_transid(dir_item, trans->transid);
1378         btrfs_set_stack_dir_data_len(dir_item, 0);
1379         btrfs_set_stack_dir_name_len(dir_item, name_len);
1380         btrfs_set_stack_dir_type(dir_item, type);
1381         memcpy((char *)(dir_item + 1), name, name_len);
1382
1383         ret = btrfs_delayed_item_reserve_metadata(trans, dir->root, delayed_item);
1384         /*
1385          * we have reserved enough space when we start a new transaction,
1386          * so reserving metadata failure is impossible
1387          */
1388         BUG_ON(ret);
1389
1390         mutex_lock(&delayed_node->mutex);
1391         ret = __btrfs_add_delayed_insertion_item(delayed_node, delayed_item);
1392         if (unlikely(ret)) {
1393                 btrfs_err(trans->fs_info,
1394                           "err add delayed dir index item(name: %.*s) into the insertion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
1395                           name_len, name, delayed_node->root->root_key.objectid,
1396                           delayed_node->inode_id, ret);
1397                 BUG();
1398         }
1399         mutex_unlock(&delayed_node->mutex);
1400
1401 release_node:
1402         btrfs_release_delayed_node(delayed_node);
1403         return ret;
1404 }
1405
1406 static int btrfs_delete_delayed_insertion_item(struct btrfs_fs_info *fs_info,
1407                                                struct btrfs_delayed_node *node,
1408                                                struct btrfs_key *key)
1409 {
1410         struct btrfs_delayed_item *item;
1411
1412         mutex_lock(&node->mutex);
1413         item = __btrfs_lookup_delayed_insertion_item(node, key);
1414         if (!item) {
1415                 mutex_unlock(&node->mutex);
1416                 return 1;
1417         }
1418
1419         btrfs_delayed_item_release_metadata(node->root, item);
1420         btrfs_release_delayed_item(item);
1421         mutex_unlock(&node->mutex);
1422         return 0;
1423 }
1424
1425 int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
1426                                    struct btrfs_inode *dir, u64 index)
1427 {
1428         struct btrfs_delayed_node *node;
1429         struct btrfs_delayed_item *item;
1430         struct btrfs_key item_key;
1431         int ret;
1432
1433         node = btrfs_get_or_create_delayed_node(dir);
1434         if (IS_ERR(node))
1435                 return PTR_ERR(node);
1436
1437         item_key.objectid = btrfs_ino(dir);
1438         item_key.type = BTRFS_DIR_INDEX_KEY;
1439         item_key.offset = index;
1440
1441         ret = btrfs_delete_delayed_insertion_item(trans->fs_info, node,
1442                                                   &item_key);
1443         if (!ret)
1444                 goto end;
1445
1446         item = btrfs_alloc_delayed_item(0);
1447         if (!item) {
1448                 ret = -ENOMEM;
1449                 goto end;
1450         }
1451
1452         item->key = item_key;
1453
1454         ret = btrfs_delayed_item_reserve_metadata(trans, dir->root, item);
1455         /*
1456          * we have reserved enough space when we start a new transaction,
1457          * so reserving metadata failure is impossible.
1458          */
1459         if (ret < 0) {
1460                 btrfs_err(trans->fs_info,
1461 "metadata reservation failed for delayed dir item deltiona, should have been reserved");
1462                 btrfs_release_delayed_item(item);
1463                 goto end;
1464         }
1465
1466         mutex_lock(&node->mutex);
1467         ret = __btrfs_add_delayed_deletion_item(node, item);
1468         if (unlikely(ret)) {
1469                 btrfs_err(trans->fs_info,
1470                           "err add delayed dir index item(index: %llu) into the deletion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
1471                           index, node->root->root_key.objectid,
1472                           node->inode_id, ret);
1473                 btrfs_delayed_item_release_metadata(dir->root, item);
1474                 btrfs_release_delayed_item(item);
1475         }
1476         mutex_unlock(&node->mutex);
1477 end:
1478         btrfs_release_delayed_node(node);
1479         return ret;
1480 }
1481
1482 int btrfs_inode_delayed_dir_index_count(struct btrfs_inode *inode)
1483 {
1484         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1485
1486         if (!delayed_node)
1487                 return -ENOENT;
1488
1489         /*
1490          * Since we have held i_mutex of this directory, it is impossible that
1491          * a new directory index is added into the delayed node and index_cnt
1492          * is updated now. So we needn't lock the delayed node.
1493          */
1494         if (!delayed_node->index_cnt) {
1495                 btrfs_release_delayed_node(delayed_node);
1496                 return -EINVAL;
1497         }
1498
1499         inode->index_cnt = delayed_node->index_cnt;
1500         btrfs_release_delayed_node(delayed_node);
1501         return 0;
1502 }
1503
1504 bool btrfs_readdir_get_delayed_items(struct inode *inode,
1505                                      struct list_head *ins_list,
1506                                      struct list_head *del_list)
1507 {
1508         struct btrfs_delayed_node *delayed_node;
1509         struct btrfs_delayed_item *item;
1510
1511         delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1512         if (!delayed_node)
1513                 return false;
1514
1515         /*
1516          * We can only do one readdir with delayed items at a time because of
1517          * item->readdir_list.
1518          */
1519         btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
1520         btrfs_inode_lock(inode, 0);
1521
1522         mutex_lock(&delayed_node->mutex);
1523         item = __btrfs_first_delayed_insertion_item(delayed_node);
1524         while (item) {
1525                 refcount_inc(&item->refs);
1526                 list_add_tail(&item->readdir_list, ins_list);
1527                 item = __btrfs_next_delayed_item(item);
1528         }
1529
1530         item = __btrfs_first_delayed_deletion_item(delayed_node);
1531         while (item) {
1532                 refcount_inc(&item->refs);
1533                 list_add_tail(&item->readdir_list, del_list);
1534                 item = __btrfs_next_delayed_item(item);
1535         }
1536         mutex_unlock(&delayed_node->mutex);
1537         /*
1538          * This delayed node is still cached in the btrfs inode, so refs
1539          * must be > 1 now, and we needn't check it is going to be freed
1540          * or not.
1541          *
1542          * Besides that, this function is used to read dir, we do not
1543          * insert/delete delayed items in this period. So we also needn't
1544          * requeue or dequeue this delayed node.
1545          */
1546         refcount_dec(&delayed_node->refs);
1547
1548         return true;
1549 }
1550
1551 void btrfs_readdir_put_delayed_items(struct inode *inode,
1552                                      struct list_head *ins_list,
1553                                      struct list_head *del_list)
1554 {
1555         struct btrfs_delayed_item *curr, *next;
1556
1557         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1558                 list_del(&curr->readdir_list);
1559                 if (refcount_dec_and_test(&curr->refs))
1560                         kfree(curr);
1561         }
1562
1563         list_for_each_entry_safe(curr, next, del_list, readdir_list) {
1564                 list_del(&curr->readdir_list);
1565                 if (refcount_dec_and_test(&curr->refs))
1566                         kfree(curr);
1567         }
1568
1569         /*
1570          * The VFS is going to do up_read(), so we need to downgrade back to a
1571          * read lock.
1572          */
1573         downgrade_write(&inode->i_rwsem);
1574 }
1575
1576 int btrfs_should_delete_dir_index(struct list_head *del_list,
1577                                   u64 index)
1578 {
1579         struct btrfs_delayed_item *curr;
1580         int ret = 0;
1581
1582         list_for_each_entry(curr, del_list, readdir_list) {
1583                 if (curr->key.offset > index)
1584                         break;
1585                 if (curr->key.offset == index) {
1586                         ret = 1;
1587                         break;
1588                 }
1589         }
1590         return ret;
1591 }
1592
1593 /*
1594  * btrfs_readdir_delayed_dir_index - read dir info stored in the delayed tree
1595  *
1596  */
1597 int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
1598                                     struct list_head *ins_list)
1599 {
1600         struct btrfs_dir_item *di;
1601         struct btrfs_delayed_item *curr, *next;
1602         struct btrfs_key location;
1603         char *name;
1604         int name_len;
1605         int over = 0;
1606         unsigned char d_type;
1607
1608         if (list_empty(ins_list))
1609                 return 0;
1610
1611         /*
1612          * Changing the data of the delayed item is impossible. So
1613          * we needn't lock them. And we have held i_mutex of the
1614          * directory, nobody can delete any directory indexes now.
1615          */
1616         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1617                 list_del(&curr->readdir_list);
1618
1619                 if (curr->key.offset < ctx->pos) {
1620                         if (refcount_dec_and_test(&curr->refs))
1621                                 kfree(curr);
1622                         continue;
1623                 }
1624
1625                 ctx->pos = curr->key.offset;
1626
1627                 di = (struct btrfs_dir_item *)curr->data;
1628                 name = (char *)(di + 1);
1629                 name_len = btrfs_stack_dir_name_len(di);
1630
1631                 d_type = fs_ftype_to_dtype(di->type);
1632                 btrfs_disk_key_to_cpu(&location, &di->location);
1633
1634                 over = !dir_emit(ctx, name, name_len,
1635                                location.objectid, d_type);
1636
1637                 if (refcount_dec_and_test(&curr->refs))
1638                         kfree(curr);
1639
1640                 if (over)
1641                         return 1;
1642                 ctx->pos++;
1643         }
1644         return 0;
1645 }
1646
1647 static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
1648                                   struct btrfs_inode_item *inode_item,
1649                                   struct inode *inode)
1650 {
1651         u64 flags;
1652
1653         btrfs_set_stack_inode_uid(inode_item, i_uid_read(inode));
1654         btrfs_set_stack_inode_gid(inode_item, i_gid_read(inode));
1655         btrfs_set_stack_inode_size(inode_item, BTRFS_I(inode)->disk_i_size);
1656         btrfs_set_stack_inode_mode(inode_item, inode->i_mode);
1657         btrfs_set_stack_inode_nlink(inode_item, inode->i_nlink);
1658         btrfs_set_stack_inode_nbytes(inode_item, inode_get_bytes(inode));
1659         btrfs_set_stack_inode_generation(inode_item,
1660                                          BTRFS_I(inode)->generation);
1661         btrfs_set_stack_inode_sequence(inode_item,
1662                                        inode_peek_iversion(inode));
1663         btrfs_set_stack_inode_transid(inode_item, trans->transid);
1664         btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
1665         flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
1666                                           BTRFS_I(inode)->ro_flags);
1667         btrfs_set_stack_inode_flags(inode_item, flags);
1668         btrfs_set_stack_inode_block_group(inode_item, 0);
1669
1670         btrfs_set_stack_timespec_sec(&inode_item->atime,
1671                                      inode->i_atime.tv_sec);
1672         btrfs_set_stack_timespec_nsec(&inode_item->atime,
1673                                       inode->i_atime.tv_nsec);
1674
1675         btrfs_set_stack_timespec_sec(&inode_item->mtime,
1676                                      inode->i_mtime.tv_sec);
1677         btrfs_set_stack_timespec_nsec(&inode_item->mtime,
1678                                       inode->i_mtime.tv_nsec);
1679
1680         btrfs_set_stack_timespec_sec(&inode_item->ctime,
1681                                      inode->i_ctime.tv_sec);
1682         btrfs_set_stack_timespec_nsec(&inode_item->ctime,
1683                                       inode->i_ctime.tv_nsec);
1684
1685         btrfs_set_stack_timespec_sec(&inode_item->otime,
1686                                      BTRFS_I(inode)->i_otime.tv_sec);
1687         btrfs_set_stack_timespec_nsec(&inode_item->otime,
1688                                      BTRFS_I(inode)->i_otime.tv_nsec);
1689 }
1690
1691 int btrfs_fill_inode(struct inode *inode, u32 *rdev)
1692 {
1693         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1694         struct btrfs_delayed_node *delayed_node;
1695         struct btrfs_inode_item *inode_item;
1696
1697         delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1698         if (!delayed_node)
1699                 return -ENOENT;
1700
1701         mutex_lock(&delayed_node->mutex);
1702         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1703                 mutex_unlock(&delayed_node->mutex);
1704                 btrfs_release_delayed_node(delayed_node);
1705                 return -ENOENT;
1706         }
1707
1708         inode_item = &delayed_node->inode_item;
1709
1710         i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
1711         i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
1712         btrfs_i_size_write(BTRFS_I(inode), btrfs_stack_inode_size(inode_item));
1713         btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
1714                         round_up(i_size_read(inode), fs_info->sectorsize));
1715         inode->i_mode = btrfs_stack_inode_mode(inode_item);
1716         set_nlink(inode, btrfs_stack_inode_nlink(inode_item));
1717         inode_set_bytes(inode, btrfs_stack_inode_nbytes(inode_item));
1718         BTRFS_I(inode)->generation = btrfs_stack_inode_generation(inode_item);
1719         BTRFS_I(inode)->last_trans = btrfs_stack_inode_transid(inode_item);
1720
1721         inode_set_iversion_queried(inode,
1722                                    btrfs_stack_inode_sequence(inode_item));
1723         inode->i_rdev = 0;
1724         *rdev = btrfs_stack_inode_rdev(inode_item);
1725         btrfs_inode_split_flags(btrfs_stack_inode_flags(inode_item),
1726                                 &BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags);
1727
1728         inode->i_atime.tv_sec = btrfs_stack_timespec_sec(&inode_item->atime);
1729         inode->i_atime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->atime);
1730
1731         inode->i_mtime.tv_sec = btrfs_stack_timespec_sec(&inode_item->mtime);
1732         inode->i_mtime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->mtime);
1733
1734         inode->i_ctime.tv_sec = btrfs_stack_timespec_sec(&inode_item->ctime);
1735         inode->i_ctime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->ctime);
1736
1737         BTRFS_I(inode)->i_otime.tv_sec =
1738                 btrfs_stack_timespec_sec(&inode_item->otime);
1739         BTRFS_I(inode)->i_otime.tv_nsec =
1740                 btrfs_stack_timespec_nsec(&inode_item->otime);
1741
1742         inode->i_generation = BTRFS_I(inode)->generation;
1743         BTRFS_I(inode)->index_cnt = (u64)-1;
1744
1745         mutex_unlock(&delayed_node->mutex);
1746         btrfs_release_delayed_node(delayed_node);
1747         return 0;
1748 }
1749
1750 int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
1751                                struct btrfs_root *root,
1752                                struct btrfs_inode *inode)
1753 {
1754         struct btrfs_delayed_node *delayed_node;
1755         int ret = 0;
1756
1757         delayed_node = btrfs_get_or_create_delayed_node(inode);
1758         if (IS_ERR(delayed_node))
1759                 return PTR_ERR(delayed_node);
1760
1761         mutex_lock(&delayed_node->mutex);
1762         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1763                 fill_stack_inode_item(trans, &delayed_node->inode_item,
1764                                       &inode->vfs_inode);
1765                 goto release_node;
1766         }
1767
1768         ret = btrfs_delayed_inode_reserve_metadata(trans, root, delayed_node);
1769         if (ret)
1770                 goto release_node;
1771
1772         fill_stack_inode_item(trans, &delayed_node->inode_item, &inode->vfs_inode);
1773         set_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
1774         delayed_node->count++;
1775         atomic_inc(&root->fs_info->delayed_root->items);
1776 release_node:
1777         mutex_unlock(&delayed_node->mutex);
1778         btrfs_release_delayed_node(delayed_node);
1779         return ret;
1780 }
1781
1782 int btrfs_delayed_delete_inode_ref(struct btrfs_inode *inode)
1783 {
1784         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1785         struct btrfs_delayed_node *delayed_node;
1786
1787         /*
1788          * we don't do delayed inode updates during log recovery because it
1789          * leads to enospc problems.  This means we also can't do
1790          * delayed inode refs
1791          */
1792         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
1793                 return -EAGAIN;
1794
1795         delayed_node = btrfs_get_or_create_delayed_node(inode);
1796         if (IS_ERR(delayed_node))
1797                 return PTR_ERR(delayed_node);
1798
1799         /*
1800          * We don't reserve space for inode ref deletion is because:
1801          * - We ONLY do async inode ref deletion for the inode who has only
1802          *   one link(i_nlink == 1), it means there is only one inode ref.
1803          *   And in most case, the inode ref and the inode item are in the
1804          *   same leaf, and we will deal with them at the same time.
1805          *   Since we are sure we will reserve the space for the inode item,
1806          *   it is unnecessary to reserve space for inode ref deletion.
1807          * - If the inode ref and the inode item are not in the same leaf,
1808          *   We also needn't worry about enospc problem, because we reserve
1809          *   much more space for the inode update than it needs.
1810          * - At the worst, we can steal some space from the global reservation.
1811          *   It is very rare.
1812          */
1813         mutex_lock(&delayed_node->mutex);
1814         if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags))
1815                 goto release_node;
1816
1817         set_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags);
1818         delayed_node->count++;
1819         atomic_inc(&fs_info->delayed_root->items);
1820 release_node:
1821         mutex_unlock(&delayed_node->mutex);
1822         btrfs_release_delayed_node(delayed_node);
1823         return 0;
1824 }
1825
1826 static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
1827 {
1828         struct btrfs_root *root = delayed_node->root;
1829         struct btrfs_fs_info *fs_info = root->fs_info;
1830         struct btrfs_delayed_item *curr_item, *prev_item;
1831
1832         mutex_lock(&delayed_node->mutex);
1833         curr_item = __btrfs_first_delayed_insertion_item(delayed_node);
1834         while (curr_item) {
1835                 btrfs_delayed_item_release_metadata(root, curr_item);
1836                 prev_item = curr_item;
1837                 curr_item = __btrfs_next_delayed_item(prev_item);
1838                 btrfs_release_delayed_item(prev_item);
1839         }
1840
1841         curr_item = __btrfs_first_delayed_deletion_item(delayed_node);
1842         while (curr_item) {
1843                 btrfs_delayed_item_release_metadata(root, curr_item);
1844                 prev_item = curr_item;
1845                 curr_item = __btrfs_next_delayed_item(prev_item);
1846                 btrfs_release_delayed_item(prev_item);
1847         }
1848
1849         btrfs_release_delayed_iref(delayed_node);
1850
1851         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1852                 btrfs_delayed_inode_release_metadata(fs_info, delayed_node, false);
1853                 btrfs_release_delayed_inode(delayed_node);
1854         }
1855         mutex_unlock(&delayed_node->mutex);
1856 }
1857
1858 void btrfs_kill_delayed_inode_items(struct btrfs_inode *inode)
1859 {
1860         struct btrfs_delayed_node *delayed_node;
1861
1862         delayed_node = btrfs_get_delayed_node(inode);
1863         if (!delayed_node)
1864                 return;
1865
1866         __btrfs_kill_delayed_node(delayed_node);
1867         btrfs_release_delayed_node(delayed_node);
1868 }
1869
1870 void btrfs_kill_all_delayed_nodes(struct btrfs_root *root)
1871 {
1872         u64 inode_id = 0;
1873         struct btrfs_delayed_node *delayed_nodes[8];
1874         int i, n;
1875
1876         while (1) {
1877                 spin_lock(&root->inode_lock);
1878                 n = radix_tree_gang_lookup(&root->delayed_nodes_tree,
1879                                            (void **)delayed_nodes, inode_id,
1880                                            ARRAY_SIZE(delayed_nodes));
1881                 if (!n) {
1882                         spin_unlock(&root->inode_lock);
1883                         break;
1884                 }
1885
1886                 inode_id = delayed_nodes[n - 1]->inode_id + 1;
1887                 for (i = 0; i < n; i++) {
1888                         /*
1889                          * Don't increase refs in case the node is dead and
1890                          * about to be removed from the tree in the loop below
1891                          */
1892                         if (!refcount_inc_not_zero(&delayed_nodes[i]->refs))
1893                                 delayed_nodes[i] = NULL;
1894                 }
1895                 spin_unlock(&root->inode_lock);
1896
1897                 for (i = 0; i < n; i++) {
1898                         if (!delayed_nodes[i])
1899                                 continue;
1900                         __btrfs_kill_delayed_node(delayed_nodes[i]);
1901                         btrfs_release_delayed_node(delayed_nodes[i]);
1902                 }
1903         }
1904 }
1905
1906 void btrfs_destroy_delayed_inodes(struct btrfs_fs_info *fs_info)
1907 {
1908         struct btrfs_delayed_node *curr_node, *prev_node;
1909
1910         curr_node = btrfs_first_delayed_node(fs_info->delayed_root);
1911         while (curr_node) {
1912                 __btrfs_kill_delayed_node(curr_node);
1913
1914                 prev_node = curr_node;
1915                 curr_node = btrfs_next_delayed_node(curr_node);
1916                 btrfs_release_delayed_node(prev_node);
1917         }
1918 }
1919