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 #include "inode-item.h"
  17
  18 #define BTRFS_DELAYED_WRITEBACK         512
  19 #define BTRFS_DELAYED_BACKGROUND        128
  20 #define BTRFS_DELAYED_BATCH             16
  21
  22 static struct kmem_cache *delayed_node_cache;
  23
  24 int __init btrfs_delayed_inode_init(void)
  25 {
  26         delayed_node_cache = kmem_cache_create("btrfs_delayed_node",
  27                                         sizeof(struct btrfs_delayed_node),
  28                                         0,
  29                                         SLAB_MEM_SPREAD,
  30                                         NULL);
  31         if (!delayed_node_cache)
  32                 return -ENOMEM;
  33         return 0;
  34 }
  35
  36 void __cold btrfs_delayed_inode_exit(void)
  37 {
  38         kmem_cache_destroy(delayed_node_cache);
  39 }
  40
  41 static inline void btrfs_init_delayed_node(
  42                                 struct btrfs_delayed_node *delayed_node,
  43                                 struct btrfs_root *root, u64 inode_id)
  44 {
  45         delayed_node->root = root;
  46         delayed_node->inode_id = inode_id;
  47         refcount_set(&delayed_node->refs, 0);
  48         delayed_node->ins_root = RB_ROOT_CACHED;
  49         delayed_node->del_root = RB_ROOT_CACHED;
  50         mutex_init(&delayed_node->mutex);
  51         INIT_LIST_HEAD(&delayed_node->n_list);
  52         INIT_LIST_HEAD(&delayed_node->p_list);
  53 }
  54
  55 static inline int btrfs_is_continuous_delayed_item(
  56                                         struct btrfs_delayed_item *item1,
  57                                         struct btrfs_delayed_item *item2)
  58 {
  59         if (item1->key.type == BTRFS_DIR_INDEX_KEY &&
  60             item1->key.objectid == item2->key.objectid &&
  61             item1->key.type == item2->key.type &&
  62             item1->key.offset + 1 == item2->key.offset)
  63                 return 1;
  64         return 0;
  65 }
  66
  67 static struct btrfs_delayed_node *btrfs_get_delayed_node(
  68                 struct btrfs_inode *btrfs_inode)
  69 {
  70         struct btrfs_root *root = btrfs_inode->root;
  71         u64 ino = btrfs_ino(btrfs_inode);
  72         struct btrfs_delayed_node *node;
  73
  74         node = READ_ONCE(btrfs_inode->delayed_node);
  75         if (node) {
  76                 refcount_inc(&node->refs);
  77                 return node;
  78         }
  79
  80         spin_lock(&root->inode_lock);
  81         node = radix_tree_lookup(&root->delayed_nodes_tree, ino);
  82
  83         if (node) {
  84                 if (btrfs_inode->delayed_node) {
  85                         refcount_inc(&node->refs);      /* can be accessed */
  86                         BUG_ON(btrfs_inode->delayed_node != node);
  87                         spin_unlock(&root->inode_lock);
  88                         return node;
  89                 }
  90
  91                 /*
  92                  * It's possible that we're racing into the middle of removing
  93                  * this node from the radix tree.  In this case, the refcount
  94                  * was zero and it should never go back to one.  Just return
  95                  * NULL like it was never in the radix at all; our release
  96                  * function is in the process of removing it.
  97                  *
  98                  * Some implementations of refcount_inc refuse to bump the
  99                  * refcount once it has hit zero.  If we don't do this dance
 100                  * here, refcount_inc() may decide to just WARN_ONCE() instead
 101                  * of actually bumping the refcount.
 102                  *
 103                  * If this node is properly in the radix, we want to bump the
 104                  * refcount twice, once for the inode and once for this get
 105                  * operation.
 106                  */
 107                 if (refcount_inc_not_zero(&node->refs)) {
 108                         refcount_inc(&node->refs);
 109                         btrfs_inode->delayed_node = node;
 110                 } else {
 111                         node = NULL;
 112                 }
 113
 114                 spin_unlock(&root->inode_lock);
 115                 return node;
 116         }
 117         spin_unlock(&root->inode_lock);
 118
 119         return NULL;
 120 }
 121
 122 /* Will return either the node or PTR_ERR(-ENOMEM) */
 123 static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
 124                 struct btrfs_inode *btrfs_inode)
 125 {
 126         struct btrfs_delayed_node *node;
 127         struct btrfs_root *root = btrfs_inode->root;
 128         u64 ino = btrfs_ino(btrfs_inode);
 129         int ret;
 130
 131 again:
 132         node = btrfs_get_delayed_node(btrfs_inode);
 133         if (node)
 134                 return node;
 135
 136         node = kmem_cache_zalloc(delayed_node_cache, GFP_NOFS);
 137         if (!node)
 138                 return ERR_PTR(-ENOMEM);
 139         btrfs_init_delayed_node(node, root, ino);
 140
 141         /* cached in the btrfs inode and can be accessed */
 142         refcount_set(&node->refs, 2);
 143
 144         ret = radix_tree_preload(GFP_NOFS);
 145         if (ret) {
 146                 kmem_cache_free(delayed_node_cache, node);
 147                 return ERR_PTR(ret);
 148         }
 149
 150         spin_lock(&root->inode_lock);
 151         ret = radix_tree_insert(&root->delayed_nodes_tree, ino, node);
 152         if (ret == -EEXIST) {
 153                 spin_unlock(&root->inode_lock);
 154                 kmem_cache_free(delayed_node_cache, node);
 155                 radix_tree_preload_end();
 156                 goto again;
 157         }
 158         btrfs_inode->delayed_node = node;
 159         spin_unlock(&root->inode_lock);
 160         radix_tree_preload_end();
 161
 162         return node;
 163 }
 164
 165 /*
 166  * Call it when holding delayed_node->mutex
 167  *
 168  * If mod = 1, add this node into the prepared list.
 169  */
 170 static void btrfs_queue_delayed_node(struct btrfs_delayed_root *root,
 171                                      struct btrfs_delayed_node *node,
 172                                      int mod)
 173 {
 174         spin_lock(&root->lock);
 175         if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 176                 if (!list_empty(&node->p_list))
 177                         list_move_tail(&node->p_list, &root->prepare_list);
 178                 else if (mod)
 179                         list_add_tail(&node->p_list, &root->prepare_list);
 180         } else {
 181                 list_add_tail(&node->n_list, &root->node_list);
 182                 list_add_tail(&node->p_list, &root->prepare_list);
 183                 refcount_inc(&node->refs);      /* inserted into list */
 184                 root->nodes++;
 185                 set_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 186         }
 187         spin_unlock(&root->lock);
 188 }
 189
 190 /* Call it when holding delayed_node->mutex */
 191 static void btrfs_dequeue_delayed_node(struct btrfs_delayed_root *root,
 192                                        struct btrfs_delayed_node *node)
 193 {
 194         spin_lock(&root->lock);
 195         if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 196                 root->nodes--;
 197                 refcount_dec(&node->refs);      /* not in the list */
 198                 list_del_init(&node->n_list);
 199                 if (!list_empty(&node->p_list))
 200                         list_del_init(&node->p_list);
 201                 clear_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 202         }
 203         spin_unlock(&root->lock);
 204 }
 205
 206 static struct btrfs_delayed_node *btrfs_first_delayed_node(
 207                         struct btrfs_delayed_root *delayed_root)
 208 {
 209         struct list_head *p;
 210         struct btrfs_delayed_node *node = NULL;
 211
 212         spin_lock(&delayed_root->lock);
 213         if (list_empty(&delayed_root->node_list))
 214                 goto out;
 215
 216         p = delayed_root->node_list.next;
 217         node = list_entry(p, struct btrfs_delayed_node, n_list);
 218         refcount_inc(&node->refs);
 219 out:
 220         spin_unlock(&delayed_root->lock);
 221
 222         return node;
 223 }
 224
 225 static struct btrfs_delayed_node *btrfs_next_delayed_node(
 226                                                 struct btrfs_delayed_node *node)
 227 {
 228         struct btrfs_delayed_root *delayed_root;
 229         struct list_head *p;
 230         struct btrfs_delayed_node *next = NULL;
 231
 232         delayed_root = node->root->fs_info->delayed_root;
 233         spin_lock(&delayed_root->lock);
 234         if (!test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 235                 /* not in the list */
 236                 if (list_empty(&delayed_root->node_list))
 237                         goto out;
 238                 p = delayed_root->node_list.next;
 239         } else if (list_is_last(&node->n_list, &delayed_root->node_list))
 240                 goto out;
 241         else
 242                 p = node->n_list.next;
 243
 244         next = list_entry(p, struct btrfs_delayed_node, n_list);
 245         refcount_inc(&next->refs);
 246 out:
 247         spin_unlock(&delayed_root->lock);
 248
 249         return next;
 250 }
 251
 252 static void __btrfs_release_delayed_node(
 253                                 struct btrfs_delayed_node *delayed_node,
 254                                 int mod)
 255 {
 256         struct btrfs_delayed_root *delayed_root;
 257
 258         if (!delayed_node)
 259                 return;
 260
 261         delayed_root = delayed_node->root->fs_info->delayed_root;
 262
 263         mutex_lock(&delayed_node->mutex);
 264         if (delayed_node->count)
 265                 btrfs_queue_delayed_node(delayed_root, delayed_node, mod);
 266         else
 267                 btrfs_dequeue_delayed_node(delayed_root, delayed_node);
 268         mutex_unlock(&delayed_node->mutex);
 269
 270         if (refcount_dec_and_test(&delayed_node->refs)) {
 271                 struct btrfs_root *root = delayed_node->root;
 272
 273                 spin_lock(&root->inode_lock);
 274                 /*
 275                  * Once our refcount goes to zero, nobody is allowed to bump it
 276                  * back up.  We can delete it now.
 277                  */
 278                 ASSERT(refcount_read(&delayed_node->refs) == 0);
 279                 radix_tree_delete(&root->delayed_nodes_tree,
 280                                   delayed_node->inode_id);
 281                 spin_unlock(&root->inode_lock);
 282                 kmem_cache_free(delayed_node_cache, delayed_node);
 283         }
 284 }
 285
 286 static inline void btrfs_release_delayed_node(struct btrfs_delayed_node *node)
 287 {
 288         __btrfs_release_delayed_node(node, 0);
 289 }
 290
 291 static struct btrfs_delayed_node *btrfs_first_prepared_delayed_node(
 292                                         struct btrfs_delayed_root *delayed_root)
 293 {
 294         struct list_head *p;
 295         struct btrfs_delayed_node *node = NULL;
 296
 297         spin_lock(&delayed_root->lock);
 298         if (list_empty(&delayed_root->prepare_list))
 299                 goto out;
 300
 301         p = delayed_root->prepare_list.next;
 302         list_del_init(p);
 303         node = list_entry(p, struct btrfs_delayed_node, p_list);
 304         refcount_inc(&node->refs);
 305 out:
 306         spin_unlock(&delayed_root->lock);
 307
 308         return node;
 309 }
 310
 311 static inline void btrfs_release_prepared_delayed_node(
 312                                         struct btrfs_delayed_node *node)
 313 {
 314         __btrfs_release_delayed_node(node, 1);
 315 }
 316
 317 static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u32 data_len)
 318 {
 319         struct btrfs_delayed_item *item;
 320         item = kmalloc(sizeof(*item) + data_len, GFP_NOFS);
 321         if (item) {
 322                 item->data_len = data_len;
 323                 item->ins_or_del = 0;
 324                 item->bytes_reserved = 0;
 325                 item->delayed_node = NULL;
 326                 refcount_set(&item->refs, 1);
 327         }
 328         return item;
 329 }
 330
 331 /*
 332  * __btrfs_lookup_delayed_item - look up the delayed item by key
 333  * @delayed_node: pointer to the delayed node
 334  * @key:          the key to look up
 335  * @prev:         used to store the prev item if the right item isn't found
 336  * @next:         used to store the next item if the right item isn't found
 337  *
 338  * Note: if we don't find the right item, we will return the prev item and
 339  * the next item.
 340  */
 341 static struct btrfs_delayed_item *__btrfs_lookup_delayed_item(
 342                                 struct rb_root *root,
 343                                 struct btrfs_key *key,
 344                                 struct btrfs_delayed_item **prev,
 345                                 struct btrfs_delayed_item **next)
 346 {
 347         struct rb_node *node, *prev_node = NULL;
 348         struct btrfs_delayed_item *delayed_item = NULL;
 349         int ret = 0;
 350
 351         node = root->rb_node;
 352
 353         while (node) {
 354                 delayed_item = rb_entry(node, struct btrfs_delayed_item,
 355                                         rb_node);
 356                 prev_node = node;
 357                 ret = btrfs_comp_cpu_keys(&delayed_item->key, key);
 358                 if (ret < 0)
 359                         node = node->rb_right;
 360                 else if (ret > 0)
 361                         node = node->rb_left;
 362                 else
 363                         return delayed_item;
 364         }
 365
 366         if (prev) {
 367                 if (!prev_node)
 368                         *prev = NULL;
 369                 else if (ret < 0)
 370                         *prev = delayed_item;
 371                 else if ((node = rb_prev(prev_node)) != NULL) {
 372                         *prev = rb_entry(node, struct btrfs_delayed_item,
 373                                          rb_node);
 374                 } else
 375                         *prev = NULL;
 376         }
 377
 378         if (next) {
 379                 if (!prev_node)
 380                         *next = NULL;
 381                 else if (ret > 0)
 382                         *next = delayed_item;
 383                 else if ((node = rb_next(prev_node)) != NULL) {
 384                         *next = rb_entry(node, struct btrfs_delayed_item,
 385                                          rb_node);
 386                 } else
 387                         *next = NULL;
 388         }
 389         return NULL;
 390 }
 391
 392 static struct btrfs_delayed_item *__btrfs_lookup_delayed_insertion_item(
 393                                         struct btrfs_delayed_node *delayed_node,
 394                                         struct btrfs_key *key)
 395 {
 396         return __btrfs_lookup_delayed_item(&delayed_node->ins_root.rb_root, key,
 397                                            NULL, NULL);
 398 }
 399
 400 static int __btrfs_add_delayed_item(struct btrfs_delayed_node *delayed_node,
 401                                     struct btrfs_delayed_item *ins,
 402                                     int action)
 403 {
 404         struct rb_node **p, *node;
 405         struct rb_node *parent_node = NULL;
 406         struct rb_root_cached *root;
 407         struct btrfs_delayed_item *item;
 408         int cmp;
 409         bool leftmost = true;
 410
 411         if (action == BTRFS_DELAYED_INSERTION_ITEM)
 412                 root = &delayed_node->ins_root;
 413         else if (action == BTRFS_DELAYED_DELETION_ITEM)
 414                 root = &delayed_node->del_root;
 415         else
 416                 BUG();
 417         p = &root->rb_root.rb_node;
 418         node = &ins->rb_node;
 419
 420         while (*p) {
 421                 parent_node = *p;
 422                 item = rb_entry(parent_node, struct btrfs_delayed_item,
 423                                  rb_node);
 424
 425                 cmp = btrfs_comp_cpu_keys(&item->key, &ins->key);
 426                 if (cmp < 0) {
 427                         p = &(*p)->rb_right;
 428                         leftmost = false;
 429                 } else if (cmp > 0) {
 430                         p = &(*p)->rb_left;
 431                 } else {
 432                         return -EEXIST;
 433                 }
 434         }
 435
 436         rb_link_node(node, parent_node, p);
 437         rb_insert_color_cached(node, root, leftmost);
 438         ins->delayed_node = delayed_node;
 439         ins->ins_or_del = action;
 440
 441         if (ins->key.type == BTRFS_DIR_INDEX_KEY &&
 442             action == BTRFS_DELAYED_INSERTION_ITEM &&
 443             ins->key.offset >= delayed_node->index_cnt)
 444                         delayed_node->index_cnt = ins->key.offset + 1;
 445
 446         delayed_node->count++;
 447         atomic_inc(&delayed_node->root->fs_info->delayed_root->items);
 448         return 0;
 449 }
 450
 451 static int __btrfs_add_delayed_insertion_item(struct btrfs_delayed_node *node,
 452                                               struct btrfs_delayed_item *item)
 453 {
 454         return __btrfs_add_delayed_item(node, item,
 455                                         BTRFS_DELAYED_INSERTION_ITEM);
 456 }
 457
 458 static int __btrfs_add_delayed_deletion_item(struct btrfs_delayed_node *node,
 459                                              struct btrfs_delayed_item *item)
 460 {
 461         return __btrfs_add_delayed_item(node, item,
 462                                         BTRFS_DELAYED_DELETION_ITEM);
 463 }
 464
 465 static void finish_one_item(struct btrfs_delayed_root *delayed_root)
 466 {
 467         int seq = atomic_inc_return(&delayed_root->items_seq);
 468
 469         /* atomic_dec_return implies a barrier */
 470         if ((atomic_dec_return(&delayed_root->items) <
 471             BTRFS_DELAYED_BACKGROUND || seq % BTRFS_DELAYED_BATCH == 0))
 472                 cond_wake_up_nomb(&delayed_root->wait);
 473 }
 474
 475 static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item)
 476 {
 477         struct rb_root_cached *root;
 478         struct btrfs_delayed_root *delayed_root;
 479
 480         /* Not associated with any delayed_node */
 481         if (!delayed_item->delayed_node)
 482                 return;
 483         delayed_root = delayed_item->delayed_node->root->fs_info->delayed_root;
 484
 485         BUG_ON(!delayed_root);
 486         BUG_ON(delayed_item->ins_or_del != BTRFS_DELAYED_DELETION_ITEM &&
 487                delayed_item->ins_or_del != BTRFS_DELAYED_INSERTION_ITEM);
 488
 489         if (delayed_item->ins_or_del == BTRFS_DELAYED_INSERTION_ITEM)
 490                 root = &delayed_item->delayed_node->ins_root;
 491         else
 492                 root = &delayed_item->delayed_node->del_root;
 493
 494         rb_erase_cached(&delayed_item->rb_node, root);
 495         delayed_item->delayed_node->count--;
 496
 497         finish_one_item(delayed_root);
 498 }
 499
 500 static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
 501 {
 502         if (item) {
 503                 __btrfs_remove_delayed_item(item);
 504                 if (refcount_dec_and_test(&item->refs))
 505                         kfree(item);
 506         }
 507 }
 508
 509 static struct btrfs_delayed_item *__btrfs_first_delayed_insertion_item(
 510                                         struct btrfs_delayed_node *delayed_node)
 511 {
 512         struct rb_node *p;
 513         struct btrfs_delayed_item *item = NULL;
 514
 515         p = rb_first_cached(&delayed_node->ins_root);
 516         if (p)
 517                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 518
 519         return item;
 520 }
 521
 522 static struct btrfs_delayed_item *__btrfs_first_delayed_deletion_item(
 523                                         struct btrfs_delayed_node *delayed_node)
 524 {
 525         struct rb_node *p;
 526         struct btrfs_delayed_item *item = NULL;
 527
 528         p = rb_first_cached(&delayed_node->del_root);
 529         if (p)
 530                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 531
 532         return item;
 533 }
 534
 535 static struct btrfs_delayed_item *__btrfs_next_delayed_item(
 536                                                 struct btrfs_delayed_item *item)
 537 {
 538         struct rb_node *p;
 539         struct btrfs_delayed_item *next = NULL;
 540
 541         p = rb_next(&item->rb_node);
 542         if (p)
 543                 next = rb_entry(p, struct btrfs_delayed_item, rb_node);
 544
 545         return next;
 546 }
 547
 548 static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
 549                                                struct btrfs_root *root,
 550                                                struct btrfs_delayed_item *item)
 551 {
 552         struct btrfs_block_rsv *src_rsv;
 553         struct btrfs_block_rsv *dst_rsv;
 554         struct btrfs_fs_info *fs_info = root->fs_info;
 555         u64 num_bytes;
 556         int ret;
 557
 558         if (!trans->bytes_reserved)
 559                 return 0;
 560
 561         src_rsv = trans->block_rsv;
 562         dst_rsv = &fs_info->delayed_block_rsv;
 563
 564         num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
 565
 566         /*
 567          * Here we migrate space rsv from transaction rsv, since have already
 568          * reserved space when starting a transaction.  So no need to reserve
 569          * qgroup space here.
 570          */
 571         ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 572         if (!ret) {
 573                 trace_btrfs_space_reservation(fs_info, "delayed_item",
 574                                               item->key.objectid,
 575                                               num_bytes, 1);
 576                 item->bytes_reserved = num_bytes;
 577         }
 578
 579         return ret;
 580 }
 581
 582 static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
 583                                                 struct btrfs_delayed_item *item)
 584 {
 585         struct btrfs_block_rsv *rsv;
 586         struct btrfs_fs_info *fs_info = root->fs_info;
 587
 588         if (!item->bytes_reserved)
 589                 return;
 590
 591         rsv = &fs_info->delayed_block_rsv;
 592         /*
 593          * Check btrfs_delayed_item_reserve_metadata() to see why we don't need
 594          * to release/reserve qgroup space.
 595          */
 596         trace_btrfs_space_reservation(fs_info, "delayed_item",
 597                                       item->key.objectid, item->bytes_reserved,
 598                                       0);
 599         btrfs_block_rsv_release(fs_info, rsv, item->bytes_reserved, NULL);
 600 }
 601
 602 static int btrfs_delayed_inode_reserve_metadata(
 603                                         struct btrfs_trans_handle *trans,
 604                                         struct btrfs_root *root,
 605                                         struct btrfs_delayed_node *node)
 606 {
 607         struct btrfs_fs_info *fs_info = root->fs_info;
 608         struct btrfs_block_rsv *src_rsv;
 609         struct btrfs_block_rsv *dst_rsv;
 610         u64 num_bytes;
 611         int ret;
 612
 613         src_rsv = trans->block_rsv;
 614         dst_rsv = &fs_info->delayed_block_rsv;
 615
 616         num_bytes = btrfs_calc_metadata_size(fs_info, 1);
 617
 618         /*
 619          * btrfs_dirty_inode will update the inode under btrfs_join_transaction
 620          * which doesn't reserve space for speed.  This is a problem since we
 621          * still need to reserve space for this update, so try to reserve the
 622          * space.
 623          *
 624          * Now if src_rsv == delalloc_block_rsv we'll let it just steal since
 625          * we always reserve enough to update the inode item.
 626          */
 627         if (!src_rsv || (!trans->bytes_reserved &&
 628                          src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) {
 629                 ret = btrfs_qgroup_reserve_meta(root, num_bytes,
 630                                           BTRFS_QGROUP_RSV_META_PREALLOC, true);
 631                 if (ret < 0)
 632                         return ret;
 633                 ret = btrfs_block_rsv_add(fs_info, dst_rsv, num_bytes,
 634                                           BTRFS_RESERVE_NO_FLUSH);
 635                 /* NO_FLUSH could only fail with -ENOSPC */
 636                 ASSERT(ret == 0 || ret == -ENOSPC);
 637                 if (ret)
 638                         btrfs_qgroup_free_meta_prealloc(root, num_bytes);
 639         } else {
 640                 ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 641         }
 642
 643         if (!ret) {
 644                 trace_btrfs_space_reservation(fs_info, "delayed_inode",
 645                                               node->inode_id, num_bytes, 1);
 646                 node->bytes_reserved = num_bytes;
 647         }
 648
 649         return ret;
 650 }
 651
 652 static void btrfs_delayed_inode_release_metadata(struct btrfs_fs_info *fs_info,
 653                                                 struct btrfs_delayed_node *node,
 654                                                 bool qgroup_free)
 655 {
 656         struct btrfs_block_rsv *rsv;
 657
 658         if (!node->bytes_reserved)
 659                 return;
 660
 661         rsv = &fs_info->delayed_block_rsv;
 662         trace_btrfs_space_reservation(fs_info, "delayed_inode",
 663                                       node->inode_id, node->bytes_reserved, 0);
 664         btrfs_block_rsv_release(fs_info, rsv, node->bytes_reserved, NULL);
 665         if (qgroup_free)
 666                 btrfs_qgroup_free_meta_prealloc(node->root,
 667                                 node->bytes_reserved);
 668         else
 669                 btrfs_qgroup_convert_reserved_meta(node->root,
 670                                 node->bytes_reserved);
 671         node->bytes_reserved = 0;
 672 }
 673
 674 /*
 675  * Insert a single delayed item or a batch of delayed items that have consecutive
 676  * keys if they exist.
 677  */
 678 static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 679                                      struct btrfs_root *root,
 680                                      struct btrfs_path *path,
 681                                      struct btrfs_delayed_item *first_item)
 682 {
 683         LIST_HEAD(item_list);
 684         struct btrfs_delayed_item *curr;
 685         struct btrfs_delayed_item *next;
 686         const int max_size = BTRFS_LEAF_DATA_SIZE(root->fs_info);
 687         struct btrfs_item_batch batch;
 688         int total_size;
 689         char *ins_data = NULL;
 690         int ret;
 691
 692         list_add_tail(&first_item->tree_list, &item_list);
 693         batch.total_data_size = first_item->data_len;
 694         batch.nr = 1;
 695         total_size = first_item->data_len + sizeof(struct btrfs_item);
 696         curr = first_item;
 697
 698         while (true) {
 699                 int next_size;
 700
 701                 next = __btrfs_next_delayed_item(curr);
 702                 if (!next || !btrfs_is_continuous_delayed_item(curr, next))
 703                         break;
 704
 705                 next_size = next->data_len + sizeof(struct btrfs_item);
 706                 if (total_size + next_size > max_size)
 707                         break;
 708
 709                 list_add_tail(&next->tree_list, &item_list);
 710                 batch.nr++;
 711                 total_size += next_size;
 712                 batch.total_data_size += next->data_len;
 713                 curr = next;
 714         }
 715
 716         if (batch.nr == 1) {
 717                 batch.keys = &first_item->key;
 718                 batch.data_sizes = &first_item->data_len;
 719         } else {
 720                 struct btrfs_key *ins_keys;
 721                 u32 *ins_sizes;
 722                 int i = 0;
 723
 724                 ins_data = kmalloc(batch.nr * sizeof(u32) +
 725                                    batch.nr * sizeof(struct btrfs_key), GFP_NOFS);
 726                 if (!ins_data) {
 727                         ret = -ENOMEM;
 728                         goto out;
 729                 }
 730                 ins_sizes = (u32 *)ins_data;
 731                 ins_keys = (struct btrfs_key *)(ins_data + batch.nr * sizeof(u32));
 732                 batch.keys = ins_keys;
 733                 batch.data_sizes = ins_sizes;
 734                 list_for_each_entry(curr, &item_list, tree_list) {
 735                         ins_keys[i] = curr->key;
 736                         ins_sizes[i] = curr->data_len;
 737                         i++;
 738                 }
 739         }
 740
 741         ret = btrfs_insert_empty_items(trans, root, path, &batch);
 742         if (ret)
 743                 goto out;
 744
 745         list_for_each_entry(curr, &item_list, tree_list) {
 746                 char *data_ptr;
 747
 748                 data_ptr = btrfs_item_ptr(path->nodes[0], path->slots[0], char);
 749                 write_extent_buffer(path->nodes[0], &curr->data,
 750                                     (unsigned long)data_ptr, curr->data_len);
 751                 path->slots[0]++;
 752         }
 753
 754         /*
 755          * Now release our path before releasing the delayed items and their
 756          * metadata reservations, so that we don't block other tasks for more
 757          * time than needed.
 758          */
 759         btrfs_release_path(path);
 760
 761         list_for_each_entry_safe(curr, next, &item_list, tree_list) {
 762                 list_del(&curr->tree_list);
 763                 btrfs_delayed_item_release_metadata(root, curr);
 764                 btrfs_release_delayed_item(curr);
 765         }
 766 out:
 767         kfree(ins_data);
 768         return ret;
 769 }
 770
 771 static int btrfs_insert_delayed_items(struct btrfs_trans_handle *trans,
 772                                       struct btrfs_path *path,
 773                                       struct btrfs_root *root,
 774                                       struct btrfs_delayed_node *node)
 775 {
 776         int ret = 0;
 777
 778         while (ret == 0) {
 779                 struct btrfs_delayed_item *curr;
 780
 781                 mutex_lock(&node->mutex);
 782                 curr = __btrfs_first_delayed_insertion_item(node);
 783                 if (!curr) {
 784                         mutex_unlock(&node->mutex);
 785                         break;
 786                 }
 787                 ret = btrfs_insert_delayed_item(trans, root, path, curr);
 788                 mutex_unlock(&node->mutex);
 789         }
 790
 791         return ret;
 792 }
 793
 794 static int btrfs_batch_delete_items(struct btrfs_trans_handle *trans,
 795                                     struct btrfs_root *root,
 796                                     struct btrfs_path *path,
 797                                     struct btrfs_delayed_item *item)
 798 {
 799         struct btrfs_delayed_item *curr, *next;
 800         struct extent_buffer *leaf;
 801         struct btrfs_key key;
 802         struct list_head head;
 803         int nitems, i, last_item;
 804         int ret = 0;
 805
 806         BUG_ON(!path->nodes[0]);
 807
 808         leaf = path->nodes[0];
 809
 810         i = path->slots[0];
 811         last_item = btrfs_header_nritems(leaf) - 1;
 812         if (i > last_item)
 813                 return -ENOENT; /* FIXME: Is errno suitable? */
 814
 815         next = item;
 816         INIT_LIST_HEAD(&head);
 817         btrfs_item_key_to_cpu(leaf, &key, i);
 818         nitems = 0;
 819         /*
 820          * count the number of the dir index items that we can delete in batch
 821          */
 822         while (btrfs_comp_cpu_keys(&next->key, &key) == 0) {
 823                 list_add_tail(&next->tree_list, &head);
 824                 nitems++;
 825
 826                 curr = next;
 827                 next = __btrfs_next_delayed_item(curr);
 828                 if (!next)
 829                         break;
 830
 831                 if (!btrfs_is_continuous_delayed_item(curr, next))
 832                         break;
 833
 834                 i++;
 835                 if (i > last_item)
 836                         break;
 837                 btrfs_item_key_to_cpu(leaf, &key, i);
 838         }
 839
 840         if (!nitems)
 841                 return 0;
 842
 843         ret = btrfs_del_items(trans, root, path, path->slots[0], nitems);
 844         if (ret)
 845                 goto out;
 846
 847         list_for_each_entry_safe(curr, next, &head, tree_list) {
 848                 btrfs_delayed_item_release_metadata(root, curr);
 849                 list_del(&curr->tree_list);
 850                 btrfs_release_delayed_item(curr);
 851         }
 852
 853 out:
 854         return ret;
 855 }
 856
 857 static int btrfs_delete_delayed_items(struct btrfs_trans_handle *trans,
 858                                       struct btrfs_path *path,
 859                                       struct btrfs_root *root,
 860                                       struct btrfs_delayed_node *node)
 861 {
 862         struct btrfs_delayed_item *curr, *prev;
 863         int ret = 0;
 864
 865 do_again:
 866         mutex_lock(&node->mutex);
 867         curr = __btrfs_first_delayed_deletion_item(node);
 868         if (!curr)
 869                 goto delete_fail;
 870
 871         ret = btrfs_search_slot(trans, root, &curr->key, path, -1, 1);
 872         if (ret < 0)
 873                 goto delete_fail;
 874         else if (ret > 0) {
 875                 /*
 876                  * can't find the item which the node points to, so this node
 877                  * is invalid, just drop it.
 878                  */
 879                 prev = curr;
 880                 curr = __btrfs_next_delayed_item(prev);
 881                 btrfs_release_delayed_item(prev);
 882                 ret = 0;
 883                 btrfs_release_path(path);
 884                 if (curr) {
 885                         mutex_unlock(&node->mutex);
 886                         goto do_again;
 887                 } else
 888                         goto delete_fail;
 889         }
 890
 891         btrfs_batch_delete_items(trans, root, path, curr);
 892         btrfs_release_path(path);
 893         mutex_unlock(&node->mutex);
 894         goto do_again;
 895
 896 delete_fail:
 897         btrfs_release_path(path);
 898         mutex_unlock(&node->mutex);
 899         return ret;
 900 }
 901
 902 static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
 903 {
 904         struct btrfs_delayed_root *delayed_root;
 905
 906         if (delayed_node &&
 907             test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
 908                 BUG_ON(!delayed_node->root);
 909                 clear_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
 910                 delayed_node->count--;
 911
 912                 delayed_root = delayed_node->root->fs_info->delayed_root;
 913                 finish_one_item(delayed_root);
 914         }
 915 }
 916
 917 static void btrfs_release_delayed_iref(struct btrfs_delayed_node *delayed_node)
 918 {
 919
 920         if (test_and_clear_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags)) {
 921                 struct btrfs_delayed_root *delayed_root;
 922
 923                 ASSERT(delayed_node->root);
 924                 delayed_node->count--;
 925
 926                 delayed_root = delayed_node->root->fs_info->delayed_root;
 927                 finish_one_item(delayed_root);
 928         }
 929 }
 930
 931 static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
 932                                         struct btrfs_root *root,
 933                                         struct btrfs_path *path,
 934                                         struct btrfs_delayed_node *node)
 935 {
 936         struct btrfs_fs_info *fs_info = root->fs_info;
 937         struct btrfs_key key;
 938         struct btrfs_inode_item *inode_item;
 939         struct extent_buffer *leaf;
 940         int mod;
 941         int ret;
 942
 943         key.objectid = node->inode_id;
 944         key.type = BTRFS_INODE_ITEM_KEY;
 945         key.offset = 0;
 946
 947         if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
 948                 mod = -1;
 949         else
 950                 mod = 1;
 951
 952         ret = btrfs_lookup_inode(trans, root, path, &key, mod);
 953         if (ret > 0)
 954                 ret = -ENOENT;
 955         if (ret < 0)
 956                 goto out;
 957
 958         leaf = path->nodes[0];
 959         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 960                                     struct btrfs_inode_item);
 961         write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
 962                             sizeof(struct btrfs_inode_item));
 963         btrfs_mark_buffer_dirty(leaf);
 964
 965         if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
 966                 goto out;
 967
 968         path->slots[0]++;
 969         if (path->slots[0] >= btrfs_header_nritems(leaf))
 970                 goto search;
 971 again:
 972         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 973         if (key.objectid != node->inode_id)
 974                 goto out;
 975
 976         if (key.type != BTRFS_INODE_REF_KEY &&
 977             key.type != BTRFS_INODE_EXTREF_KEY)
 978                 goto out;
 979
 980         /*
 981          * Delayed iref deletion is for the inode who has only one link,
 982          * so there is only one iref. The case that several irefs are
 983          * in the same item doesn't exist.
 984          */
 985         btrfs_del_item(trans, root, path);
 986 out:
 987         btrfs_release_delayed_iref(node);
 988         btrfs_release_path(path);
 989 err_out:
 990         btrfs_delayed_inode_release_metadata(fs_info, node, (ret < 0));
 991         btrfs_release_delayed_inode(node);
 992
 993         /*
 994          * If we fail to update the delayed inode we need to abort the
 995          * transaction, because we could leave the inode with the improper
 996          * counts behind.
 997          */
 998         if (ret && ret != -ENOENT)
 999                 btrfs_abort_transaction(trans, ret);
1000
1001         return ret;
1002
1003 search:
1004         btrfs_release_path(path);
1005
1006         key.type = BTRFS_INODE_EXTREF_KEY;
1007         key.offset = -1;
1008
1009         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1010         if (ret < 0)
1011                 goto err_out;
1012         ASSERT(ret);
1013
1014         ret = 0;
1015         leaf = path->nodes[0];
1016         path->slots[0]--;
1017         goto again;
1018 }
1019
1020 static inline int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
1021                                              struct btrfs_root *root,
1022                                              struct btrfs_path *path,
1023                                              struct btrfs_delayed_node *node)
1024 {
1025         int ret;
1026
1027         mutex_lock(&node->mutex);
1028         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &node->flags)) {
1029                 mutex_unlock(&node->mutex);
1030                 return 0;
1031         }
1032
1033         ret = __btrfs_update_delayed_inode(trans, root, path, node);
1034         mutex_unlock(&node->mutex);
1035         return ret;
1036 }
1037
1038 static inline int
1039 __btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1040                                    struct btrfs_path *path,
1041                                    struct btrfs_delayed_node *node)
1042 {
1043         int ret;
1044
1045         ret = btrfs_insert_delayed_items(trans, path, node->root, node);
1046         if (ret)
1047                 return ret;
1048
1049         ret = btrfs_delete_delayed_items(trans, path, node->root, node);
1050         if (ret)
1051                 return ret;
1052
1053         ret = btrfs_update_delayed_inode(trans, node->root, path, node);
1054         return ret;
1055 }
1056
1057 /*
1058  * Called when committing the transaction.
1059  * Returns 0 on success.
1060  * Returns < 0 on error and returns with an aborted transaction with any
1061  * outstanding delayed items cleaned up.
1062  */
1063 static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
1064 {
1065         struct btrfs_fs_info *fs_info = trans->fs_info;
1066         struct btrfs_delayed_root *delayed_root;
1067         struct btrfs_delayed_node *curr_node, *prev_node;
1068         struct btrfs_path *path;
1069         struct btrfs_block_rsv *block_rsv;
1070         int ret = 0;
1071         bool count = (nr > 0);
1072
1073         if (TRANS_ABORTED(trans))
1074                 return -EIO;
1075
1076         path = btrfs_alloc_path();
1077         if (!path)
1078                 return -ENOMEM;
1079
1080         block_rsv = trans->block_rsv;
1081         trans->block_rsv = &fs_info->delayed_block_rsv;
1082
1083         delayed_root = fs_info->delayed_root;
1084
1085         curr_node = btrfs_first_delayed_node(delayed_root);
1086         while (curr_node && (!count || nr--)) {
1087                 ret = __btrfs_commit_inode_delayed_items(trans, path,
1088                                                          curr_node);
1089                 if (ret) {
1090                         btrfs_release_delayed_node(curr_node);
1091                         curr_node = NULL;
1092                         btrfs_abort_transaction(trans, ret);
1093                         break;
1094                 }
1095
1096                 prev_node = curr_node;
1097                 curr_node = btrfs_next_delayed_node(curr_node);
1098                 btrfs_release_delayed_node(prev_node);
1099         }
1100
1101         if (curr_node)
1102                 btrfs_release_delayed_node(curr_node);
1103         btrfs_free_path(path);
1104         trans->block_rsv = block_rsv;
1105
1106         return ret;
1107 }
1108
1109 int btrfs_run_delayed_items(struct btrfs_trans_handle *trans)
1110 {
1111         return __btrfs_run_delayed_items(trans, -1);
1112 }
1113
1114 int btrfs_run_delayed_items_nr(struct btrfs_trans_handle *trans, int nr)
1115 {
1116         return __btrfs_run_delayed_items(trans, nr);
1117 }
1118
1119 int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1120                                      struct btrfs_inode *inode)
1121 {
1122         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1123         struct btrfs_path *path;
1124         struct btrfs_block_rsv *block_rsv;
1125         int ret;
1126
1127         if (!delayed_node)
1128                 return 0;
1129
1130         mutex_lock(&delayed_node->mutex);
1131         if (!delayed_node->count) {
1132                 mutex_unlock(&delayed_node->mutex);
1133                 btrfs_release_delayed_node(delayed_node);
1134                 return 0;
1135         }
1136         mutex_unlock(&delayed_node->mutex);
1137
1138         path = btrfs_alloc_path();
1139         if (!path) {
1140                 btrfs_release_delayed_node(delayed_node);
1141                 return -ENOMEM;
1142         }
1143
1144         block_rsv = trans->block_rsv;
1145         trans->block_rsv = &delayed_node->root->fs_info->delayed_block_rsv;
1146
1147         ret = __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1148
1149         btrfs_release_delayed_node(delayed_node);
1150         btrfs_free_path(path);
1151         trans->block_rsv = block_rsv;
1152
1153         return ret;
1154 }
1155
1156 int btrfs_commit_inode_delayed_inode(struct btrfs_inode *inode)
1157 {
1158         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1159         struct btrfs_trans_handle *trans;
1160         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1161         struct btrfs_path *path;
1162         struct btrfs_block_rsv *block_rsv;
1163         int ret;
1164
1165         if (!delayed_node)
1166                 return 0;
1167
1168         mutex_lock(&delayed_node->mutex);
1169         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1170                 mutex_unlock(&delayed_node->mutex);
1171                 btrfs_release_delayed_node(delayed_node);
1172                 return 0;
1173         }
1174         mutex_unlock(&delayed_node->mutex);
1175
1176         trans = btrfs_join_transaction(delayed_node->root);
1177         if (IS_ERR(trans)) {
1178                 ret = PTR_ERR(trans);
1179                 goto out;
1180         }
1181
1182         path = btrfs_alloc_path();
1183         if (!path) {
1184                 ret = -ENOMEM;
1185                 goto trans_out;
1186         }
1187
1188         block_rsv = trans->block_rsv;
1189         trans->block_rsv = &fs_info->delayed_block_rsv;
1190
1191         mutex_lock(&delayed_node->mutex);
1192         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags))
1193                 ret = __btrfs_update_delayed_inode(trans, delayed_node->root,
1194                                                    path, delayed_node);
1195         else
1196                 ret = 0;
1197         mutex_unlock(&delayed_node->mutex);
1198
1199         btrfs_free_path(path);
1200         trans->block_rsv = block_rsv;
1201 trans_out:
1202         btrfs_end_transaction(trans);
1203         btrfs_btree_balance_dirty(fs_info);
1204 out:
1205         btrfs_release_delayed_node(delayed_node);
1206
1207         return ret;
1208 }
1209
1210 void btrfs_remove_delayed_node(struct btrfs_inode *inode)
1211 {
1212         struct btrfs_delayed_node *delayed_node;
1213
1214         delayed_node = READ_ONCE(inode->delayed_node);
1215         if (!delayed_node)
1216                 return;
1217
1218         inode->delayed_node = NULL;
1219         btrfs_release_delayed_node(delayed_node);
1220 }
1221
1222 struct btrfs_async_delayed_work {
1223         struct btrfs_delayed_root *delayed_root;
1224         int nr;
1225         struct btrfs_work work;
1226 };
1227
1228 static void btrfs_async_run_delayed_root(struct btrfs_work *work)
1229 {
1230         struct btrfs_async_delayed_work *async_work;
1231         struct btrfs_delayed_root *delayed_root;
1232         struct btrfs_trans_handle *trans;
1233         struct btrfs_path *path;
1234         struct btrfs_delayed_node *delayed_node = NULL;
1235         struct btrfs_root *root;
1236         struct btrfs_block_rsv *block_rsv;
1237         int total_done = 0;
1238
1239         async_work = container_of(work, struct btrfs_async_delayed_work, work);
1240         delayed_root = async_work->delayed_root;
1241
1242         path = btrfs_alloc_path();
1243         if (!path)
1244                 goto out;
1245
1246         do {
1247                 if (atomic_read(&delayed_root->items) <
1248                     BTRFS_DELAYED_BACKGROUND / 2)
1249                         break;
1250
1251                 delayed_node = btrfs_first_prepared_delayed_node(delayed_root);
1252                 if (!delayed_node)
1253                         break;
1254
1255                 root = delayed_node->root;
1256
1257                 trans = btrfs_join_transaction(root);
1258                 if (IS_ERR(trans)) {
1259                         btrfs_release_path(path);
1260                         btrfs_release_prepared_delayed_node(delayed_node);
1261                         total_done++;
1262                         continue;
1263                 }
1264
1265                 block_rsv = trans->block_rsv;
1266                 trans->block_rsv = &root->fs_info->delayed_block_rsv;
1267
1268                 __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1269
1270                 trans->block_rsv = block_rsv;
1271                 btrfs_end_transaction(trans);
1272                 btrfs_btree_balance_dirty_nodelay(root->fs_info);
1273
1274                 btrfs_release_path(path);
1275                 btrfs_release_prepared_delayed_node(delayed_node);
1276                 total_done++;
1277
1278         } while ((async_work->nr == 0 && total_done < BTRFS_DELAYED_WRITEBACK)
1279                  || total_done < async_work->nr);
1280
1281         btrfs_free_path(path);
1282 out:
1283         wake_up(&delayed_root->wait);
1284         kfree(async_work);
1285 }
1286
1287
1288 static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
1289                                      struct btrfs_fs_info *fs_info, int nr)
1290 {
1291         struct btrfs_async_delayed_work *async_work;
1292
1293         async_work = kmalloc(sizeof(*async_work), GFP_NOFS);
1294         if (!async_work)
1295                 return -ENOMEM;
1296
1297         async_work->delayed_root = delayed_root;
1298         btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root, NULL,
1299                         NULL);
1300         async_work->nr = nr;
1301
1302         btrfs_queue_work(fs_info->delayed_workers, &async_work->work);
1303         return 0;
1304 }
1305
1306 void btrfs_assert_delayed_root_empty(struct btrfs_fs_info *fs_info)
1307 {
1308         WARN_ON(btrfs_first_delayed_node(fs_info->delayed_root));
1309 }
1310
1311 static int could_end_wait(struct btrfs_delayed_root *delayed_root, int seq)
1312 {
1313         int val = atomic_read(&delayed_root->items_seq);
1314
1315         if (val < seq || val >= seq + BTRFS_DELAYED_BATCH)
1316                 return 1;
1317
1318         if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
1319                 return 1;
1320
1321         return 0;
1322 }
1323
1324 void btrfs_balance_delayed_items(struct btrfs_fs_info *fs_info)
1325 {
1326         struct btrfs_delayed_root *delayed_root = fs_info->delayed_root;
1327
1328         if ((atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND) ||
1329                 btrfs_workqueue_normal_congested(fs_info->delayed_workers))
1330                 return;
1331
1332         if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
1333                 int seq;
1334                 int ret;
1335
1336                 seq = atomic_read(&delayed_root->items_seq);
1337
1338                 ret = btrfs_wq_run_delayed_node(delayed_root, fs_info, 0);
1339                 if (ret)
1340                         return;
1341
1342                 wait_event_interruptible(delayed_root->wait,
1343                                          could_end_wait(delayed_root, seq));
1344                 return;
1345         }
1346
1347         btrfs_wq_run_delayed_node(delayed_root, fs_info, BTRFS_DELAYED_BATCH);
1348 }
1349
1350 /* Will return 0 or -ENOMEM */
1351 int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
1352                                    const char *name, int name_len,
1353                                    struct btrfs_inode *dir,
1354                                    struct btrfs_disk_key *disk_key, u8 type,
1355                                    u64 index)
1356 {
1357         struct btrfs_delayed_node *delayed_node;
1358         struct btrfs_delayed_item *delayed_item;
1359         struct btrfs_dir_item *dir_item;
1360         int ret;
1361
1362         delayed_node = btrfs_get_or_create_delayed_node(dir);
1363         if (IS_ERR(delayed_node))
1364                 return PTR_ERR(delayed_node);
1365
1366         delayed_item = btrfs_alloc_delayed_item(sizeof(*dir_item) + name_len);
1367         if (!delayed_item) {
1368                 ret = -ENOMEM;
1369                 goto release_node;
1370         }
1371
1372         delayed_item->key.objectid = btrfs_ino(dir);
1373         delayed_item->key.type = BTRFS_DIR_INDEX_KEY;
1374         delayed_item->key.offset = index;
1375
1376         dir_item = (struct btrfs_dir_item *)delayed_item->data;
1377         dir_item->location = *disk_key;
1378         btrfs_set_stack_dir_transid(dir_item, trans->transid);
1379         btrfs_set_stack_dir_data_len(dir_item, 0);
1380         btrfs_set_stack_dir_name_len(dir_item, name_len);
1381         btrfs_set_stack_dir_type(dir_item, type);
1382         memcpy((char *)(dir_item + 1), name, name_len);
1383
1384         ret = btrfs_delayed_item_reserve_metadata(trans, dir->root, delayed_item);
1385         /*
1386          * we have reserved enough space when we start a new transaction,
1387          * so reserving metadata failure is impossible
1388          */
1389         BUG_ON(ret);
1390
1391         mutex_lock(&delayed_node->mutex);
1392         ret = __btrfs_add_delayed_insertion_item(delayed_node, delayed_item);
1393         if (unlikely(ret)) {
1394                 btrfs_err(trans->fs_info,
1395                           "err add delayed dir index item(name: %.*s) into the insertion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
1396                           name_len, name, delayed_node->root->root_key.objectid,
1397                           delayed_node->inode_id, ret);
1398                 BUG();
1399         }
1400         mutex_unlock(&delayed_node->mutex);
1401
1402 release_node:
1403         btrfs_release_delayed_node(delayed_node);
1404         return ret;
1405 }
1406
1407 static int btrfs_delete_delayed_insertion_item(struct btrfs_fs_info *fs_info,
1408                                                struct btrfs_delayed_node *node,
1409                                                struct btrfs_key *key)
1410 {
1411         struct btrfs_delayed_item *item;
1412
1413         mutex_lock(&node->mutex);
1414         item = __btrfs_lookup_delayed_insertion_item(node, key);
1415         if (!item) {
1416                 mutex_unlock(&node->mutex);
1417                 return 1;
1418         }
1419
1420         btrfs_delayed_item_release_metadata(node->root, item);
1421         btrfs_release_delayed_item(item);
1422         mutex_unlock(&node->mutex);
1423         return 0;
1424 }
1425
1426 int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
1427                                    struct btrfs_inode *dir, u64 index)
1428 {
1429         struct btrfs_delayed_node *node;
1430         struct btrfs_delayed_item *item;
1431         struct btrfs_key item_key;
1432         int ret;
1433
1434         node = btrfs_get_or_create_delayed_node(dir);
1435         if (IS_ERR(node))
1436                 return PTR_ERR(node);
1437
1438         item_key.objectid = btrfs_ino(dir);
1439         item_key.type = BTRFS_DIR_INDEX_KEY;
1440         item_key.offset = index;
1441
1442         ret = btrfs_delete_delayed_insertion_item(trans->fs_info, node,
1443                                                   &item_key);
1444         if (!ret)
1445                 goto end;
1446
1447         item = btrfs_alloc_delayed_item(0);
1448         if (!item) {
1449                 ret = -ENOMEM;
1450                 goto end;
1451         }
1452
1453         item->key = item_key;
1454
1455         ret = btrfs_delayed_item_reserve_metadata(trans, dir->root, item);
1456         /*
1457          * we have reserved enough space when we start a new transaction,
1458          * so reserving metadata failure is impossible.
1459          */
1460         if (ret < 0) {
1461                 btrfs_err(trans->fs_info,
1462 "metadata reservation failed for delayed dir item deltiona, should have been reserved");
1463                 btrfs_release_delayed_item(item);
1464                 goto end;
1465         }
1466
1467         mutex_lock(&node->mutex);
1468         ret = __btrfs_add_delayed_deletion_item(node, item);
1469         if (unlikely(ret)) {
1470                 btrfs_err(trans->fs_info,
1471                           "err add delayed dir index item(index: %llu) into the deletion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
1472                           index, node->root->root_key.objectid,
1473                           node->inode_id, ret);
1474                 btrfs_delayed_item_release_metadata(dir->root, item);
1475                 btrfs_release_delayed_item(item);
1476         }
1477         mutex_unlock(&node->mutex);
1478 end:
1479         btrfs_release_delayed_node(node);
1480         return ret;
1481 }
1482
1483 int btrfs_inode_delayed_dir_index_count(struct btrfs_inode *inode)
1484 {
1485         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1486
1487         if (!delayed_node)
1488                 return -ENOENT;
1489
1490         /*
1491          * Since we have held i_mutex of this directory, it is impossible that
1492          * a new directory index is added into the delayed node and index_cnt
1493          * is updated now. So we needn't lock the delayed node.
1494          */
1495         if (!delayed_node->index_cnt) {
1496                 btrfs_release_delayed_node(delayed_node);
1497                 return -EINVAL;
1498         }
1499
1500         inode->index_cnt = delayed_node->index_cnt;
1501         btrfs_release_delayed_node(delayed_node);
1502         return 0;
1503 }
1504
1505 bool btrfs_readdir_get_delayed_items(struct inode *inode,
1506                                      struct list_head *ins_list,
1507                                      struct list_head *del_list)
1508 {
1509         struct btrfs_delayed_node *delayed_node;
1510         struct btrfs_delayed_item *item;
1511
1512         delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1513         if (!delayed_node)
1514                 return false;
1515
1516         /*
1517          * We can only do one readdir with delayed items at a time because of
1518          * item->readdir_list.
1519          */
1520         btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
1521         btrfs_inode_lock(inode, 0);
1522
1523         mutex_lock(&delayed_node->mutex);
1524         item = __btrfs_first_delayed_insertion_item(delayed_node);
1525         while (item) {
1526                 refcount_inc(&item->refs);
1527                 list_add_tail(&item->readdir_list, ins_list);
1528                 item = __btrfs_next_delayed_item(item);
1529         }
1530
1531         item = __btrfs_first_delayed_deletion_item(delayed_node);
1532         while (item) {
1533                 refcount_inc(&item->refs);
1534                 list_add_tail(&item->readdir_list, del_list);
1535                 item = __btrfs_next_delayed_item(item);
1536         }
1537         mutex_unlock(&delayed_node->mutex);
1538         /*
1539          * This delayed node is still cached in the btrfs inode, so refs
1540          * must be > 1 now, and we needn't check it is going to be freed
1541          * or not.
1542          *
1543          * Besides that, this function is used to read dir, we do not
1544          * insert/delete delayed items in this period. So we also needn't
1545          * requeue or dequeue this delayed node.
1546          */
1547         refcount_dec(&delayed_node->refs);
1548
1549         return true;
1550 }
1551
1552 void btrfs_readdir_put_delayed_items(struct inode *inode,
1553                                      struct list_head *ins_list,
1554                                      struct list_head *del_list)
1555 {
1556         struct btrfs_delayed_item *curr, *next;
1557
1558         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1559                 list_del(&curr->readdir_list);
1560                 if (refcount_dec_and_test(&curr->refs))
1561                         kfree(curr);
1562         }
1563
1564         list_for_each_entry_safe(curr, next, del_list, readdir_list) {
1565                 list_del(&curr->readdir_list);
1566                 if (refcount_dec_and_test(&curr->refs))
1567                         kfree(curr);
1568         }
1569
1570         /*
1571          * The VFS is going to do up_read(), so we need to downgrade back to a
1572          * read lock.
1573          */
1574         downgrade_write(&inode->i_rwsem);
1575 }
1576
1577 int btrfs_should_delete_dir_index(struct list_head *del_list,
1578                                   u64 index)
1579 {
1580         struct btrfs_delayed_item *curr;
1581         int ret = 0;
1582
1583         list_for_each_entry(curr, del_list, readdir_list) {
1584                 if (curr->key.offset > index)
1585                         break;
1586                 if (curr->key.offset == index) {
1587                         ret = 1;
1588                         break;
1589                 }
1590         }
1591         return ret;
1592 }
1593
1594 /*
1595  * btrfs_readdir_delayed_dir_index - read dir info stored in the delayed tree
1596  *
1597  */
1598 int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
1599                                     struct list_head *ins_list)
1600 {
1601         struct btrfs_dir_item *di;
1602         struct btrfs_delayed_item *curr, *next;
1603         struct btrfs_key location;
1604         char *name;
1605         int name_len;
1606         int over = 0;
1607         unsigned char d_type;
1608
1609         if (list_empty(ins_list))
1610                 return 0;
1611
1612         /*
1613          * Changing the data of the delayed item is impossible. So
1614          * we needn't lock them. And we have held i_mutex of the
1615          * directory, nobody can delete any directory indexes now.
1616          */
1617         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1618                 list_del(&curr->readdir_list);
1619
1620                 if (curr->key.offset < ctx->pos) {
1621                         if (refcount_dec_and_test(&curr->refs))
1622                                 kfree(curr);
1623                         continue;
1624                 }
1625
1626                 ctx->pos = curr->key.offset;
1627
1628                 di = (struct btrfs_dir_item *)curr->data;
1629                 name = (char *)(di + 1);
1630                 name_len = btrfs_stack_dir_name_len(di);
1631
1632                 d_type = fs_ftype_to_dtype(di->type);
1633                 btrfs_disk_key_to_cpu(&location, &di->location);
1634
1635                 over = !dir_emit(ctx, name, name_len,
1636                                location.objectid, d_type);
1637
1638                 if (refcount_dec_and_test(&curr->refs))
1639                         kfree(curr);
1640
1641                 if (over)
1642                         return 1;
1643                 ctx->pos++;
1644         }
1645         return 0;
1646 }
1647
1648 static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
1649                                   struct btrfs_inode_item *inode_item,
1650                                   struct inode *inode)
1651 {
1652         u64 flags;
1653
1654         btrfs_set_stack_inode_uid(inode_item, i_uid_read(inode));
1655         btrfs_set_stack_inode_gid(inode_item, i_gid_read(inode));
1656         btrfs_set_stack_inode_size(inode_item, BTRFS_I(inode)->disk_i_size);
1657         btrfs_set_stack_inode_mode(inode_item, inode->i_mode);
1658         btrfs_set_stack_inode_nlink(inode_item, inode->i_nlink);
1659         btrfs_set_stack_inode_nbytes(inode_item, inode_get_bytes(inode));
1660         btrfs_set_stack_inode_generation(inode_item,
1661                                          BTRFS_I(inode)->generation);
1662         btrfs_set_stack_inode_sequence(inode_item,
1663                                        inode_peek_iversion(inode));
1664         btrfs_set_stack_inode_transid(inode_item, trans->transid);
1665         btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
1666         flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
1667                                           BTRFS_I(inode)->ro_flags);
1668         btrfs_set_stack_inode_flags(inode_item, flags);
1669         btrfs_set_stack_inode_block_group(inode_item, 0);
1670
1671         btrfs_set_stack_timespec_sec(&inode_item->atime,
1672                                      inode->i_atime.tv_sec);
1673         btrfs_set_stack_timespec_nsec(&inode_item->atime,
1674                                       inode->i_atime.tv_nsec);
1675
1676         btrfs_set_stack_timespec_sec(&inode_item->mtime,
1677                                      inode->i_mtime.tv_sec);
1678         btrfs_set_stack_timespec_nsec(&inode_item->mtime,
1679                                       inode->i_mtime.tv_nsec);
1680
1681         btrfs_set_stack_timespec_sec(&inode_item->ctime,
1682                                      inode->i_ctime.tv_sec);
1683         btrfs_set_stack_timespec_nsec(&inode_item->ctime,
1684                                       inode->i_ctime.tv_nsec);
1685
1686         btrfs_set_stack_timespec_sec(&inode_item->otime,
1687                                      BTRFS_I(inode)->i_otime.tv_sec);
1688         btrfs_set_stack_timespec_nsec(&inode_item->otime,
1689                                      BTRFS_I(inode)->i_otime.tv_nsec);
1690 }
1691
1692 int btrfs_fill_inode(struct inode *inode, u32 *rdev)
1693 {
1694         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1695         struct btrfs_delayed_node *delayed_node;
1696         struct btrfs_inode_item *inode_item;
1697
1698         delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1699         if (!delayed_node)
1700                 return -ENOENT;
1701
1702         mutex_lock(&delayed_node->mutex);
1703         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1704                 mutex_unlock(&delayed_node->mutex);
1705                 btrfs_release_delayed_node(delayed_node);
1706                 return -ENOENT;
1707         }
1708
1709         inode_item = &delayed_node->inode_item;
1710
1711         i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
1712         i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
1713         btrfs_i_size_write(BTRFS_I(inode), btrfs_stack_inode_size(inode_item));
1714         btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
1715                         round_up(i_size_read(inode), fs_info->sectorsize));
1716         inode->i_mode = btrfs_stack_inode_mode(inode_item);
1717         set_nlink(inode, btrfs_stack_inode_nlink(inode_item));
1718         inode_set_bytes(inode, btrfs_stack_inode_nbytes(inode_item));
1719         BTRFS_I(inode)->generation = btrfs_stack_inode_generation(inode_item);
1720         BTRFS_I(inode)->last_trans = btrfs_stack_inode_transid(inode_item);
1721
1722         inode_set_iversion_queried(inode,
1723                                    btrfs_stack_inode_sequence(inode_item));
1724         inode->i_rdev = 0;
1725         *rdev = btrfs_stack_inode_rdev(inode_item);
1726         btrfs_inode_split_flags(btrfs_stack_inode_flags(inode_item),
1727                                 &BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags);
1728
1729         inode->i_atime.tv_sec = btrfs_stack_timespec_sec(&inode_item->atime);
1730         inode->i_atime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->atime);
1731
1732         inode->i_mtime.tv_sec = btrfs_stack_timespec_sec(&inode_item->mtime);
1733         inode->i_mtime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->mtime);
1734
1735         inode->i_ctime.tv_sec = btrfs_stack_timespec_sec(&inode_item->ctime);
1736         inode->i_ctime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->ctime);
1737
1738         BTRFS_I(inode)->i_otime.tv_sec =
1739                 btrfs_stack_timespec_sec(&inode_item->otime);
1740         BTRFS_I(inode)->i_otime.tv_nsec =
1741                 btrfs_stack_timespec_nsec(&inode_item->otime);
1742
1743         inode->i_generation = BTRFS_I(inode)->generation;
1744         BTRFS_I(inode)->index_cnt = (u64)-1;
1745
1746         mutex_unlock(&delayed_node->mutex);
1747         btrfs_release_delayed_node(delayed_node);
1748         return 0;
1749 }
1750
1751 int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
1752                                struct btrfs_root *root,
1753                                struct btrfs_inode *inode)
1754 {
1755         struct btrfs_delayed_node *delayed_node;
1756         int ret = 0;
1757
1758         delayed_node = btrfs_get_or_create_delayed_node(inode);
1759         if (IS_ERR(delayed_node))
1760                 return PTR_ERR(delayed_node);
1761
1762         mutex_lock(&delayed_node->mutex);
1763         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1764                 fill_stack_inode_item(trans, &delayed_node->inode_item,
1765                                       &inode->vfs_inode);
1766                 goto release_node;
1767         }
1768
1769         ret = btrfs_delayed_inode_reserve_metadata(trans, root, delayed_node);
1770         if (ret)
1771                 goto release_node;
1772
1773         fill_stack_inode_item(trans, &delayed_node->inode_item, &inode->vfs_inode);
1774         set_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
1775         delayed_node->count++;
1776         atomic_inc(&root->fs_info->delayed_root->items);
1777 release_node:
1778         mutex_unlock(&delayed_node->mutex);
1779         btrfs_release_delayed_node(delayed_node);
1780         return ret;
1781 }
1782
1783 int btrfs_delayed_delete_inode_ref(struct btrfs_inode *inode)
1784 {
1785         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1786         struct btrfs_delayed_node *delayed_node;
1787
1788         /*
1789          * we don't do delayed inode updates during log recovery because it
1790          * leads to enospc problems.  This means we also can't do
1791          * delayed inode refs
1792          */
1793         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
1794                 return -EAGAIN;
1795
1796         delayed_node = btrfs_get_or_create_delayed_node(inode);
1797         if (IS_ERR(delayed_node))
1798                 return PTR_ERR(delayed_node);
1799
1800         /*
1801          * We don't reserve space for inode ref deletion is because:
1802          * - We ONLY do async inode ref deletion for the inode who has only
1803          *   one link(i_nlink == 1), it means there is only one inode ref.
1804          *   And in most case, the inode ref and the inode item are in the
1805          *   same leaf, and we will deal with them at the same time.
1806          *   Since we are sure we will reserve the space for the inode item,
1807          *   it is unnecessary to reserve space for inode ref deletion.
1808          * - If the inode ref and the inode item are not in the same leaf,
1809          *   We also needn't worry about enospc problem, because we reserve
1810          *   much more space for the inode update than it needs.
1811          * - At the worst, we can steal some space from the global reservation.
1812          *   It is very rare.
1813          */
1814         mutex_lock(&delayed_node->mutex);
1815         if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags))
1816                 goto release_node;
1817
1818         set_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags);
1819         delayed_node->count++;
1820         atomic_inc(&fs_info->delayed_root->items);
1821 release_node:
1822         mutex_unlock(&delayed_node->mutex);
1823         btrfs_release_delayed_node(delayed_node);
1824         return 0;
1825 }
1826
1827 static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
1828 {
1829         struct btrfs_root *root = delayed_node->root;
1830         struct btrfs_fs_info *fs_info = root->fs_info;
1831         struct btrfs_delayed_item *curr_item, *prev_item;
1832
1833         mutex_lock(&delayed_node->mutex);
1834         curr_item = __btrfs_first_delayed_insertion_item(delayed_node);
1835         while (curr_item) {
1836                 btrfs_delayed_item_release_metadata(root, curr_item);
1837                 prev_item = curr_item;
1838                 curr_item = __btrfs_next_delayed_item(prev_item);
1839                 btrfs_release_delayed_item(prev_item);
1840         }
1841
1842         curr_item = __btrfs_first_delayed_deletion_item(delayed_node);
1843         while (curr_item) {
1844                 btrfs_delayed_item_release_metadata(root, curr_item);
1845                 prev_item = curr_item;
1846                 curr_item = __btrfs_next_delayed_item(prev_item);
1847                 btrfs_release_delayed_item(prev_item);
1848         }
1849
1850         btrfs_release_delayed_iref(delayed_node);
1851
1852         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1853                 btrfs_delayed_inode_release_metadata(fs_info, delayed_node, false);
1854                 btrfs_release_delayed_inode(delayed_node);
1855         }
1856         mutex_unlock(&delayed_node->mutex);
1857 }
1858
1859 void btrfs_kill_delayed_inode_items(struct btrfs_inode *inode)
1860 {
1861         struct btrfs_delayed_node *delayed_node;
1862
1863         delayed_node = btrfs_get_delayed_node(inode);
1864         if (!delayed_node)
1865                 return;
1866
1867         __btrfs_kill_delayed_node(delayed_node);
1868         btrfs_release_delayed_node(delayed_node);
1869 }
1870
1871 void btrfs_kill_all_delayed_nodes(struct btrfs_root *root)
1872 {
1873         u64 inode_id = 0;
1874         struct btrfs_delayed_node *delayed_nodes[8];
1875         int i, n;
1876
1877         while (1) {
1878                 spin_lock(&root->inode_lock);
1879                 n = radix_tree_gang_lookup(&root->delayed_nodes_tree,
1880                                            (void **)delayed_nodes, inode_id,
1881                                            ARRAY_SIZE(delayed_nodes));
1882                 if (!n) {
1883                         spin_unlock(&root->inode_lock);
1884                         break;
1885                 }
1886
1887                 inode_id = delayed_nodes[n - 1]->inode_id + 1;
1888                 for (i = 0; i < n; i++) {
1889                         /*
1890                          * Don't increase refs in case the node is dead and
1891                          * about to be removed from the tree in the loop below
1892                          */
1893                         if (!refcount_inc_not_zero(&delayed_nodes[i]->refs))
1894                                 delayed_nodes[i] = NULL;
1895                 }
1896                 spin_unlock(&root->inode_lock);
1897
1898                 for (i = 0; i < n; i++) {
1899                         if (!delayed_nodes[i])
1900                                 continue;
1901                         __btrfs_kill_delayed_node(delayed_nodes[i]);
1902                         btrfs_release_delayed_node(delayed_nodes[i]);
1903                 }
1904         }
1905 }
1906
1907 void btrfs_destroy_delayed_inodes(struct btrfs_fs_info *fs_info)
1908 {
1909         struct btrfs_delayed_node *curr_node, *prev_node;
1910
1911         curr_node = btrfs_first_delayed_node(fs_info->delayed_root);
1912         while (curr_node) {
1913                 __btrfs_kill_delayed_node(curr_node);
1914
1915                 prev_node = curr_node;
1916                 curr_node = btrfs_next_delayed_node(curr_node);
1917                 btrfs_release_delayed_node(prev_node);
1918         }
1919 }
1920