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 "ctree.h"
  10 #include "fs.h"
  11 #include "messages.h"
  12 #include "misc.h"
  13 #include "delayed-inode.h"
  14 #include "disk-io.h"
  15 #include "transaction.h"
  16 #include "qgroup.h"
  17 #include "locking.h"
  18 #include "inode-item.h"
  19 #include "space-info.h"
  20 #include "accessors.h"
  21 #include "file-item.h"
  22
  23 #define BTRFS_DELAYED_WRITEBACK         512
  24 #define BTRFS_DELAYED_BACKGROUND        128
  25 #define BTRFS_DELAYED_BATCH             16
  26
  27 static struct kmem_cache *delayed_node_cache;
  28
  29 int __init btrfs_delayed_inode_init(void)
  30 {
  31         delayed_node_cache = KMEM_CACHE(btrfs_delayed_node, 0);
  32         if (!delayed_node_cache)
  33                 return -ENOMEM;
  34         return 0;
  35 }
  36
  37 void __cold btrfs_delayed_inode_exit(void)
  38 {
  39         kmem_cache_destroy(delayed_node_cache);
  40 }
  41
  42 void btrfs_init_delayed_root(struct btrfs_delayed_root *delayed_root)
  43 {
  44         atomic_set(&delayed_root->items, 0);
  45         atomic_set(&delayed_root->items_seq, 0);
  46         delayed_root->nodes = 0;
  47         spin_lock_init(&delayed_root->lock);
  48         init_waitqueue_head(&delayed_root->wait);
  49         INIT_LIST_HEAD(&delayed_root->node_list);
  50         INIT_LIST_HEAD(&delayed_root->prepare_list);
  51 }
  52
  53 static inline void btrfs_init_delayed_node(
  54                                 struct btrfs_delayed_node *delayed_node,
  55                                 struct btrfs_root *root, u64 inode_id)
  56 {
  57         delayed_node->root = root;
  58         delayed_node->inode_id = inode_id;
  59         refcount_set(&delayed_node->refs, 0);
  60         delayed_node->ins_root = RB_ROOT_CACHED;
  61         delayed_node->del_root = RB_ROOT_CACHED;
  62         mutex_init(&delayed_node->mutex);
  63         INIT_LIST_HEAD(&delayed_node->n_list);
  64         INIT_LIST_HEAD(&delayed_node->p_list);
  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 = xa_load(&root->delayed_nodes, 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 xarray.  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 xarray 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 xarray, 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         void *ptr;
 131
 132 again:
 133         node = btrfs_get_delayed_node(btrfs_inode);
 134         if (node)
 135                 return node;
 136
 137         node = kmem_cache_zalloc(delayed_node_cache, GFP_NOFS);
 138         if (!node)
 139                 return ERR_PTR(-ENOMEM);
 140         btrfs_init_delayed_node(node, root, ino);
 141
 142         /* Cached in the inode and can be accessed. */
 143         refcount_set(&node->refs, 2);
 144
 145         /* Allocate and reserve the slot, from now it can return a NULL from xa_load(). */
 146         ret = xa_reserve(&root->delayed_nodes, ino, GFP_NOFS);
 147         if (ret == -ENOMEM) {
 148                 kmem_cache_free(delayed_node_cache, node);
 149                 return ERR_PTR(-ENOMEM);
 150         }
 151         spin_lock(&root->inode_lock);
 152         ptr = xa_load(&root->delayed_nodes, ino);
 153         if (ptr) {
 154                 /* Somebody inserted it, go back and read it. */
 155                 spin_unlock(&root->inode_lock);
 156                 kmem_cache_free(delayed_node_cache, node);
 157                 node = NULL;
 158                 goto again;
 159         }
 160         ptr = xa_store(&root->delayed_nodes, ino, node, GFP_ATOMIC);
 161         ASSERT(xa_err(ptr) != -EINVAL);
 162         ASSERT(xa_err(ptr) != -ENOMEM);
 163         ASSERT(ptr == NULL);
 164         btrfs_inode->delayed_node = node;
 165         spin_unlock(&root->inode_lock);
 166
 167         return node;
 168 }
 169
 170 /*
 171  * Call it when holding delayed_node->mutex
 172  *
 173  * If mod = 1, add this node into the prepared list.
 174  */
 175 static void btrfs_queue_delayed_node(struct btrfs_delayed_root *root,
 176                                      struct btrfs_delayed_node *node,
 177                                      int mod)
 178 {
 179         spin_lock(&root->lock);
 180         if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 181                 if (!list_empty(&node->p_list))
 182                         list_move_tail(&node->p_list, &root->prepare_list);
 183                 else if (mod)
 184                         list_add_tail(&node->p_list, &root->prepare_list);
 185         } else {
 186                 list_add_tail(&node->n_list, &root->node_list);
 187                 list_add_tail(&node->p_list, &root->prepare_list);
 188                 refcount_inc(&node->refs);      /* inserted into list */
 189                 root->nodes++;
 190                 set_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 191         }
 192         spin_unlock(&root->lock);
 193 }
 194
 195 /* Call it when holding delayed_node->mutex */
 196 static void btrfs_dequeue_delayed_node(struct btrfs_delayed_root *root,
 197                                        struct btrfs_delayed_node *node)
 198 {
 199         spin_lock(&root->lock);
 200         if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 201                 root->nodes--;
 202                 refcount_dec(&node->refs);      /* not in the list */
 203                 list_del_init(&node->n_list);
 204                 if (!list_empty(&node->p_list))
 205                         list_del_init(&node->p_list);
 206                 clear_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 207         }
 208         spin_unlock(&root->lock);
 209 }
 210
 211 static struct btrfs_delayed_node *btrfs_first_delayed_node(
 212                         struct btrfs_delayed_root *delayed_root)
 213 {
 214         struct list_head *p;
 215         struct btrfs_delayed_node *node = NULL;
 216
 217         spin_lock(&delayed_root->lock);
 218         if (list_empty(&delayed_root->node_list))
 219                 goto out;
 220
 221         p = delayed_root->node_list.next;
 222         node = list_entry(p, struct btrfs_delayed_node, n_list);
 223         refcount_inc(&node->refs);
 224 out:
 225         spin_unlock(&delayed_root->lock);
 226
 227         return node;
 228 }
 229
 230 static struct btrfs_delayed_node *btrfs_next_delayed_node(
 231                                                 struct btrfs_delayed_node *node)
 232 {
 233         struct btrfs_delayed_root *delayed_root;
 234         struct list_head *p;
 235         struct btrfs_delayed_node *next = NULL;
 236
 237         delayed_root = node->root->fs_info->delayed_root;
 238         spin_lock(&delayed_root->lock);
 239         if (!test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 240                 /* not in the list */
 241                 if (list_empty(&delayed_root->node_list))
 242                         goto out;
 243                 p = delayed_root->node_list.next;
 244         } else if (list_is_last(&node->n_list, &delayed_root->node_list))
 245                 goto out;
 246         else
 247                 p = node->n_list.next;
 248
 249         next = list_entry(p, struct btrfs_delayed_node, n_list);
 250         refcount_inc(&next->refs);
 251 out:
 252         spin_unlock(&delayed_root->lock);
 253
 254         return next;
 255 }
 256
 257 static void __btrfs_release_delayed_node(
 258                                 struct btrfs_delayed_node *delayed_node,
 259                                 int mod)
 260 {
 261         struct btrfs_delayed_root *delayed_root;
 262
 263         if (!delayed_node)
 264                 return;
 265
 266         delayed_root = delayed_node->root->fs_info->delayed_root;
 267
 268         mutex_lock(&delayed_node->mutex);
 269         if (delayed_node->count)
 270                 btrfs_queue_delayed_node(delayed_root, delayed_node, mod);
 271         else
 272                 btrfs_dequeue_delayed_node(delayed_root, delayed_node);
 273         mutex_unlock(&delayed_node->mutex);
 274
 275         if (refcount_dec_and_test(&delayed_node->refs)) {
 276                 struct btrfs_root *root = delayed_node->root;
 277
 278                 spin_lock(&root->inode_lock);
 279                 /*
 280                  * Once our refcount goes to zero, nobody is allowed to bump it
 281                  * back up.  We can delete it now.
 282                  */
 283                 ASSERT(refcount_read(&delayed_node->refs) == 0);
 284                 xa_erase(&root->delayed_nodes, delayed_node->inode_id);
 285                 spin_unlock(&root->inode_lock);
 286                 kmem_cache_free(delayed_node_cache, delayed_node);
 287         }
 288 }
 289
 290 static inline void btrfs_release_delayed_node(struct btrfs_delayed_node *node)
 291 {
 292         __btrfs_release_delayed_node(node, 0);
 293 }
 294
 295 static struct btrfs_delayed_node *btrfs_first_prepared_delayed_node(
 296                                         struct btrfs_delayed_root *delayed_root)
 297 {
 298         struct list_head *p;
 299         struct btrfs_delayed_node *node = NULL;
 300
 301         spin_lock(&delayed_root->lock);
 302         if (list_empty(&delayed_root->prepare_list))
 303                 goto out;
 304
 305         p = delayed_root->prepare_list.next;
 306         list_del_init(p);
 307         node = list_entry(p, struct btrfs_delayed_node, p_list);
 308         refcount_inc(&node->refs);
 309 out:
 310         spin_unlock(&delayed_root->lock);
 311
 312         return node;
 313 }
 314
 315 static inline void btrfs_release_prepared_delayed_node(
 316                                         struct btrfs_delayed_node *node)
 317 {
 318         __btrfs_release_delayed_node(node, 1);
 319 }
 320
 321 static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u16 data_len,
 322                                            struct btrfs_delayed_node *node,
 323                                            enum btrfs_delayed_item_type type)
 324 {
 325         struct btrfs_delayed_item *item;
 326
 327         item = kmalloc(struct_size(item, data, data_len), GFP_NOFS);
 328         if (item) {
 329                 item->data_len = data_len;
 330                 item->type = type;
 331                 item->bytes_reserved = 0;
 332                 item->delayed_node = node;
 333                 RB_CLEAR_NODE(&item->rb_node);
 334                 INIT_LIST_HEAD(&item->log_list);
 335                 item->logged = false;
 336                 refcount_set(&item->refs, 1);
 337         }
 338         return item;
 339 }
 340
 341 /*
 342  * Look up the delayed item by key.
 343  *
 344  * @delayed_node: pointer to the delayed node
 345  * @index:        the dir index value to lookup (offset of a dir index key)
 346  *
 347  * Note: if we don't find the right item, we will return the prev item and
 348  * the next item.
 349  */
 350 static struct btrfs_delayed_item *__btrfs_lookup_delayed_item(
 351                                 struct rb_root *root,
 352                                 u64 index)
 353 {
 354         struct rb_node *node = root->rb_node;
 355         struct btrfs_delayed_item *delayed_item = NULL;
 356
 357         while (node) {
 358                 delayed_item = rb_entry(node, struct btrfs_delayed_item,
 359                                         rb_node);
 360                 if (delayed_item->index < index)
 361                         node = node->rb_right;
 362                 else if (delayed_item->index > index)
 363                         node = node->rb_left;
 364                 else
 365                         return delayed_item;
 366         }
 367
 368         return NULL;
 369 }
 370
 371 static int __btrfs_add_delayed_item(struct btrfs_delayed_node *delayed_node,
 372                                     struct btrfs_delayed_item *ins)
 373 {
 374         struct rb_node **p, *node;
 375         struct rb_node *parent_node = NULL;
 376         struct rb_root_cached *root;
 377         struct btrfs_delayed_item *item;
 378         bool leftmost = true;
 379
 380         if (ins->type == BTRFS_DELAYED_INSERTION_ITEM)
 381                 root = &delayed_node->ins_root;
 382         else
 383                 root = &delayed_node->del_root;
 384
 385         p = &root->rb_root.rb_node;
 386         node = &ins->rb_node;
 387
 388         while (*p) {
 389                 parent_node = *p;
 390                 item = rb_entry(parent_node, struct btrfs_delayed_item,
 391                                  rb_node);
 392
 393                 if (item->index < ins->index) {
 394                         p = &(*p)->rb_right;
 395                         leftmost = false;
 396                 } else if (item->index > ins->index) {
 397                         p = &(*p)->rb_left;
 398                 } else {
 399                         return -EEXIST;
 400                 }
 401         }
 402
 403         rb_link_node(node, parent_node, p);
 404         rb_insert_color_cached(node, root, leftmost);
 405
 406         if (ins->type == BTRFS_DELAYED_INSERTION_ITEM &&
 407             ins->index >= delayed_node->index_cnt)
 408                 delayed_node->index_cnt = ins->index + 1;
 409
 410         delayed_node->count++;
 411         atomic_inc(&delayed_node->root->fs_info->delayed_root->items);
 412         return 0;
 413 }
 414
 415 static void finish_one_item(struct btrfs_delayed_root *delayed_root)
 416 {
 417         int seq = atomic_inc_return(&delayed_root->items_seq);
 418
 419         /* atomic_dec_return implies a barrier */
 420         if ((atomic_dec_return(&delayed_root->items) <
 421             BTRFS_DELAYED_BACKGROUND || seq % BTRFS_DELAYED_BATCH == 0))
 422                 cond_wake_up_nomb(&delayed_root->wait);
 423 }
 424
 425 static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item)
 426 {
 427         struct btrfs_delayed_node *delayed_node = delayed_item->delayed_node;
 428         struct rb_root_cached *root;
 429         struct btrfs_delayed_root *delayed_root;
 430
 431         /* Not inserted, ignore it. */
 432         if (RB_EMPTY_NODE(&delayed_item->rb_node))
 433                 return;
 434
 435         /* If it's in a rbtree, then we need to have delayed node locked. */
 436         lockdep_assert_held(&delayed_node->mutex);
 437
 438         delayed_root = delayed_node->root->fs_info->delayed_root;
 439
 440         if (delayed_item->type == BTRFS_DELAYED_INSERTION_ITEM)
 441                 root = &delayed_node->ins_root;
 442         else
 443                 root = &delayed_node->del_root;
 444
 445         rb_erase_cached(&delayed_item->rb_node, root);
 446         RB_CLEAR_NODE(&delayed_item->rb_node);
 447         delayed_node->count--;
 448
 449         finish_one_item(delayed_root);
 450 }
 451
 452 static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
 453 {
 454         if (item) {
 455                 __btrfs_remove_delayed_item(item);
 456                 if (refcount_dec_and_test(&item->refs))
 457                         kfree(item);
 458         }
 459 }
 460
 461 static struct btrfs_delayed_item *__btrfs_first_delayed_insertion_item(
 462                                         struct btrfs_delayed_node *delayed_node)
 463 {
 464         struct rb_node *p;
 465         struct btrfs_delayed_item *item = NULL;
 466
 467         p = rb_first_cached(&delayed_node->ins_root);
 468         if (p)
 469                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 470
 471         return item;
 472 }
 473
 474 static struct btrfs_delayed_item *__btrfs_first_delayed_deletion_item(
 475                                         struct btrfs_delayed_node *delayed_node)
 476 {
 477         struct rb_node *p;
 478         struct btrfs_delayed_item *item = NULL;
 479
 480         p = rb_first_cached(&delayed_node->del_root);
 481         if (p)
 482                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 483
 484         return item;
 485 }
 486
 487 static struct btrfs_delayed_item *__btrfs_next_delayed_item(
 488                                                 struct btrfs_delayed_item *item)
 489 {
 490         struct rb_node *p;
 491         struct btrfs_delayed_item *next = NULL;
 492
 493         p = rb_next(&item->rb_node);
 494         if (p)
 495                 next = rb_entry(p, struct btrfs_delayed_item, rb_node);
 496
 497         return next;
 498 }
 499
 500 static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
 501                                                struct btrfs_delayed_item *item)
 502 {
 503         struct btrfs_block_rsv *src_rsv;
 504         struct btrfs_block_rsv *dst_rsv;
 505         struct btrfs_fs_info *fs_info = trans->fs_info;
 506         u64 num_bytes;
 507         int ret;
 508
 509         if (!trans->bytes_reserved)
 510                 return 0;
 511
 512         src_rsv = trans->block_rsv;
 513         dst_rsv = &fs_info->delayed_block_rsv;
 514
 515         num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
 516
 517         /*
 518          * Here we migrate space rsv from transaction rsv, since have already
 519          * reserved space when starting a transaction.  So no need to reserve
 520          * qgroup space here.
 521          */
 522         ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 523         if (!ret) {
 524                 trace_btrfs_space_reservation(fs_info, "delayed_item",
 525                                               item->delayed_node->inode_id,
 526                                               num_bytes, 1);
 527                 /*
 528                  * For insertions we track reserved metadata space by accounting
 529                  * for the number of leaves that will be used, based on the delayed
 530                  * node's curr_index_batch_size and index_item_leaves fields.
 531                  */
 532                 if (item->type == BTRFS_DELAYED_DELETION_ITEM)
 533                         item->bytes_reserved = num_bytes;
 534         }
 535
 536         return ret;
 537 }
 538
 539 static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
 540                                                 struct btrfs_delayed_item *item)
 541 {
 542         struct btrfs_block_rsv *rsv;
 543         struct btrfs_fs_info *fs_info = root->fs_info;
 544
 545         if (!item->bytes_reserved)
 546                 return;
 547
 548         rsv = &fs_info->delayed_block_rsv;
 549         /*
 550          * Check btrfs_delayed_item_reserve_metadata() to see why we don't need
 551          * to release/reserve qgroup space.
 552          */
 553         trace_btrfs_space_reservation(fs_info, "delayed_item",
 554                                       item->delayed_node->inode_id,
 555                                       item->bytes_reserved, 0);
 556         btrfs_block_rsv_release(fs_info, rsv, item->bytes_reserved, NULL);
 557 }
 558
 559 static void btrfs_delayed_item_release_leaves(struct btrfs_delayed_node *node,
 560                                               unsigned int num_leaves)
 561 {
 562         struct btrfs_fs_info *fs_info = node->root->fs_info;
 563         const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, num_leaves);
 564
 565         /* There are no space reservations during log replay, bail out. */
 566         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
 567                 return;
 568
 569         trace_btrfs_space_reservation(fs_info, "delayed_item", node->inode_id,
 570                                       bytes, 0);
 571         btrfs_block_rsv_release(fs_info, &fs_info->delayed_block_rsv, bytes, NULL);
 572 }
 573
 574 static int btrfs_delayed_inode_reserve_metadata(
 575                                         struct btrfs_trans_handle *trans,
 576                                         struct btrfs_root *root,
 577                                         struct btrfs_delayed_node *node)
 578 {
 579         struct btrfs_fs_info *fs_info = root->fs_info;
 580         struct btrfs_block_rsv *src_rsv;
 581         struct btrfs_block_rsv *dst_rsv;
 582         u64 num_bytes;
 583         int ret;
 584
 585         src_rsv = trans->block_rsv;
 586         dst_rsv = &fs_info->delayed_block_rsv;
 587
 588         num_bytes = btrfs_calc_metadata_size(fs_info, 1);
 589
 590         /*
 591          * btrfs_dirty_inode will update the inode under btrfs_join_transaction
 592          * which doesn't reserve space for speed.  This is a problem since we
 593          * still need to reserve space for this update, so try to reserve the
 594          * space.
 595          *
 596          * Now if src_rsv == delalloc_block_rsv we'll let it just steal since
 597          * we always reserve enough to update the inode item.
 598          */
 599         if (!src_rsv || (!trans->bytes_reserved &&
 600                          src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) {
 601                 ret = btrfs_qgroup_reserve_meta(root, num_bytes,
 602                                           BTRFS_QGROUP_RSV_META_PREALLOC, true);
 603                 if (ret < 0)
 604                         return ret;
 605                 ret = btrfs_block_rsv_add(fs_info, dst_rsv, num_bytes,
 606                                           BTRFS_RESERVE_NO_FLUSH);
 607                 /* NO_FLUSH could only fail with -ENOSPC */
 608                 ASSERT(ret == 0 || ret == -ENOSPC);
 609                 if (ret)
 610                         btrfs_qgroup_free_meta_prealloc(root, num_bytes);
 611         } else {
 612                 ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 613         }
 614
 615         if (!ret) {
 616                 trace_btrfs_space_reservation(fs_info, "delayed_inode",
 617                                               node->inode_id, num_bytes, 1);
 618                 node->bytes_reserved = num_bytes;
 619         }
 620
 621         return ret;
 622 }
 623
 624 static void btrfs_delayed_inode_release_metadata(struct btrfs_fs_info *fs_info,
 625                                                 struct btrfs_delayed_node *node,
 626                                                 bool qgroup_free)
 627 {
 628         struct btrfs_block_rsv *rsv;
 629
 630         if (!node->bytes_reserved)
 631                 return;
 632
 633         rsv = &fs_info->delayed_block_rsv;
 634         trace_btrfs_space_reservation(fs_info, "delayed_inode",
 635                                       node->inode_id, node->bytes_reserved, 0);
 636         btrfs_block_rsv_release(fs_info, rsv, node->bytes_reserved, NULL);
 637         if (qgroup_free)
 638                 btrfs_qgroup_free_meta_prealloc(node->root,
 639                                 node->bytes_reserved);
 640         else
 641                 btrfs_qgroup_convert_reserved_meta(node->root,
 642                                 node->bytes_reserved);
 643         node->bytes_reserved = 0;
 644 }
 645
 646 /*
 647  * Insert a single delayed item or a batch of delayed items, as many as possible
 648  * that fit in a leaf. The delayed items (dir index keys) are sorted by their key
 649  * in the rbtree, and if there's a gap between two consecutive dir index items,
 650  * then it means at some point we had delayed dir indexes to add but they got
 651  * removed (by btrfs_delete_delayed_dir_index()) before we attempted to flush them
 652  * into the subvolume tree. Dir index keys also have their offsets coming from a
 653  * monotonically increasing counter, so we can't get new keys with an offset that
 654  * fits within a gap between delayed dir index items.
 655  */
 656 static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 657                                      struct btrfs_root *root,
 658                                      struct btrfs_path *path,
 659                                      struct btrfs_delayed_item *first_item)
 660 {
 661         struct btrfs_fs_info *fs_info = root->fs_info;
 662         struct btrfs_delayed_node *node = first_item->delayed_node;
 663         LIST_HEAD(item_list);
 664         struct btrfs_delayed_item *curr;
 665         struct btrfs_delayed_item *next;
 666         const int max_size = BTRFS_LEAF_DATA_SIZE(fs_info);
 667         struct btrfs_item_batch batch;
 668         struct btrfs_key first_key;
 669         const u32 first_data_size = first_item->data_len;
 670         int total_size;
 671         char *ins_data = NULL;
 672         int ret;
 673         bool continuous_keys_only = false;
 674
 675         lockdep_assert_held(&node->mutex);
 676
 677         /*
 678          * During normal operation the delayed index offset is continuously
 679          * increasing, so we can batch insert all items as there will not be any
 680          * overlapping keys in the tree.
 681          *
 682          * The exception to this is log replay, where we may have interleaved
 683          * offsets in the tree, so our batch needs to be continuous keys only in
 684          * order to ensure we do not end up with out of order items in our leaf.
 685          */
 686         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
 687                 continuous_keys_only = true;
 688
 689         /*
 690          * For delayed items to insert, we track reserved metadata bytes based
 691          * on the number of leaves that we will use.
 692          * See btrfs_insert_delayed_dir_index() and
 693          * btrfs_delayed_item_reserve_metadata()).
 694          */
 695         ASSERT(first_item->bytes_reserved == 0);
 696
 697         list_add_tail(&first_item->tree_list, &item_list);
 698         batch.total_data_size = first_data_size;
 699         batch.nr = 1;
 700         total_size = first_data_size + sizeof(struct btrfs_item);
 701         curr = first_item;
 702
 703         while (true) {
 704                 int next_size;
 705
 706                 next = __btrfs_next_delayed_item(curr);
 707                 if (!next)
 708                         break;
 709
 710                 /*
 711                  * We cannot allow gaps in the key space if we're doing log
 712                  * replay.
 713                  */
 714                 if (continuous_keys_only && (next->index != curr->index + 1))
 715                         break;
 716
 717                 ASSERT(next->bytes_reserved == 0);
 718
 719                 next_size = next->data_len + sizeof(struct btrfs_item);
 720                 if (total_size + next_size > max_size)
 721                         break;
 722
 723                 list_add_tail(&next->tree_list, &item_list);
 724                 batch.nr++;
 725                 total_size += next_size;
 726                 batch.total_data_size += next->data_len;
 727                 curr = next;
 728         }
 729
 730         if (batch.nr == 1) {
 731                 first_key.objectid = node->inode_id;
 732                 first_key.type = BTRFS_DIR_INDEX_KEY;
 733                 first_key.offset = first_item->index;
 734                 batch.keys = &first_key;
 735                 batch.data_sizes = &first_data_size;
 736         } else {
 737                 struct btrfs_key *ins_keys;
 738                 u32 *ins_sizes;
 739                 int i = 0;
 740
 741                 ins_data = kmalloc(batch.nr * sizeof(u32) +
 742                                    batch.nr * sizeof(struct btrfs_key), GFP_NOFS);
 743                 if (!ins_data) {
 744                         ret = -ENOMEM;
 745                         goto out;
 746                 }
 747                 ins_sizes = (u32 *)ins_data;
 748                 ins_keys = (struct btrfs_key *)(ins_data + batch.nr * sizeof(u32));
 749                 batch.keys = ins_keys;
 750                 batch.data_sizes = ins_sizes;
 751                 list_for_each_entry(curr, &item_list, tree_list) {
 752                         ins_keys[i].objectid = node->inode_id;
 753                         ins_keys[i].type = BTRFS_DIR_INDEX_KEY;
 754                         ins_keys[i].offset = curr->index;
 755                         ins_sizes[i] = curr->data_len;
 756                         i++;
 757                 }
 758         }
 759
 760         ret = btrfs_insert_empty_items(trans, root, path, &batch);
 761         if (ret)
 762                 goto out;
 763
 764         list_for_each_entry(curr, &item_list, tree_list) {
 765                 char *data_ptr;
 766
 767                 data_ptr = btrfs_item_ptr(path->nodes[0], path->slots[0], char);
 768                 write_extent_buffer(path->nodes[0], &curr->data,
 769                                     (unsigned long)data_ptr, curr->data_len);
 770                 path->slots[0]++;
 771         }
 772
 773         /*
 774          * Now release our path before releasing the delayed items and their
 775          * metadata reservations, so that we don't block other tasks for more
 776          * time than needed.
 777          */
 778         btrfs_release_path(path);
 779
 780         ASSERT(node->index_item_leaves > 0);
 781
 782         /*
 783          * For normal operations we will batch an entire leaf's worth of delayed
 784          * items, so if there are more items to process we can decrement
 785          * index_item_leaves by 1 as we inserted 1 leaf's worth of items.
 786          *
 787          * However for log replay we may not have inserted an entire leaf's
 788          * worth of items, we may have not had continuous items, so decrementing
 789          * here would mess up the index_item_leaves accounting.  For this case
 790          * only clean up the accounting when there are no items left.
 791          */
 792         if (next && !continuous_keys_only) {
 793                 /*
 794                  * We inserted one batch of items into a leaf a there are more
 795                  * items to flush in a future batch, now release one unit of
 796                  * metadata space from the delayed block reserve, corresponding
 797                  * the leaf we just flushed to.
 798                  */
 799                 btrfs_delayed_item_release_leaves(node, 1);
 800                 node->index_item_leaves--;
 801         } else if (!next) {
 802                 /*
 803                  * There are no more items to insert. We can have a number of
 804                  * reserved leaves > 1 here - this happens when many dir index
 805                  * items are added and then removed before they are flushed (file
 806                  * names with a very short life, never span a transaction). So
 807                  * release all remaining leaves.
 808                  */
 809                 btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
 810                 node->index_item_leaves = 0;
 811         }
 812
 813         list_for_each_entry_safe(curr, next, &item_list, tree_list) {
 814                 list_del(&curr->tree_list);
 815                 btrfs_release_delayed_item(curr);
 816         }
 817 out:
 818         kfree(ins_data);
 819         return ret;
 820 }
 821
 822 static int btrfs_insert_delayed_items(struct btrfs_trans_handle *trans,
 823                                       struct btrfs_path *path,
 824                                       struct btrfs_root *root,
 825                                       struct btrfs_delayed_node *node)
 826 {
 827         int ret = 0;
 828
 829         while (ret == 0) {
 830                 struct btrfs_delayed_item *curr;
 831
 832                 mutex_lock(&node->mutex);
 833                 curr = __btrfs_first_delayed_insertion_item(node);
 834                 if (!curr) {
 835                         mutex_unlock(&node->mutex);
 836                         break;
 837                 }
 838                 ret = btrfs_insert_delayed_item(trans, root, path, curr);
 839                 mutex_unlock(&node->mutex);
 840         }
 841
 842         return ret;
 843 }
 844
 845 static int btrfs_batch_delete_items(struct btrfs_trans_handle *trans,
 846                                     struct btrfs_root *root,
 847                                     struct btrfs_path *path,
 848                                     struct btrfs_delayed_item *item)
 849 {
 850         const u64 ino = item->delayed_node->inode_id;
 851         struct btrfs_fs_info *fs_info = root->fs_info;
 852         struct btrfs_delayed_item *curr, *next;
 853         struct extent_buffer *leaf = path->nodes[0];
 854         LIST_HEAD(batch_list);
 855         int nitems, slot, last_slot;
 856         int ret;
 857         u64 total_reserved_size = item->bytes_reserved;
 858
 859         ASSERT(leaf != NULL);
 860
 861         slot = path->slots[0];
 862         last_slot = btrfs_header_nritems(leaf) - 1;
 863         /*
 864          * Our caller always gives us a path pointing to an existing item, so
 865          * this can not happen.
 866          */
 867         ASSERT(slot <= last_slot);
 868         if (WARN_ON(slot > last_slot))
 869                 return -ENOENT;
 870
 871         nitems = 1;
 872         curr = item;
 873         list_add_tail(&curr->tree_list, &batch_list);
 874
 875         /*
 876          * Keep checking if the next delayed item matches the next item in the
 877          * leaf - if so, we can add it to the batch of items to delete from the
 878          * leaf.
 879          */
 880         while (slot < last_slot) {
 881                 struct btrfs_key key;
 882
 883                 next = __btrfs_next_delayed_item(curr);
 884                 if (!next)
 885                         break;
 886
 887                 slot++;
 888                 btrfs_item_key_to_cpu(leaf, &key, slot);
 889                 if (key.objectid != ino ||
 890                     key.type != BTRFS_DIR_INDEX_KEY ||
 891                     key.offset != next->index)
 892                         break;
 893                 nitems++;
 894                 curr = next;
 895                 list_add_tail(&curr->tree_list, &batch_list);
 896                 total_reserved_size += curr->bytes_reserved;
 897         }
 898
 899         ret = btrfs_del_items(trans, root, path, path->slots[0], nitems);
 900         if (ret)
 901                 return ret;
 902
 903         /* In case of BTRFS_FS_LOG_RECOVERING items won't have reserved space */
 904         if (total_reserved_size > 0) {
 905                 /*
 906                  * Check btrfs_delayed_item_reserve_metadata() to see why we
 907                  * don't need to release/reserve qgroup space.
 908                  */
 909                 trace_btrfs_space_reservation(fs_info, "delayed_item", ino,
 910                                               total_reserved_size, 0);
 911                 btrfs_block_rsv_release(fs_info, &fs_info->delayed_block_rsv,
 912                                         total_reserved_size, NULL);
 913         }
 914
 915         list_for_each_entry_safe(curr, next, &batch_list, tree_list) {
 916                 list_del(&curr->tree_list);
 917                 btrfs_release_delayed_item(curr);
 918         }
 919
 920         return 0;
 921 }
 922
 923 static int btrfs_delete_delayed_items(struct btrfs_trans_handle *trans,
 924                                       struct btrfs_path *path,
 925                                       struct btrfs_root *root,
 926                                       struct btrfs_delayed_node *node)
 927 {
 928         struct btrfs_key key;
 929         int ret = 0;
 930
 931         key.objectid = node->inode_id;
 932         key.type = BTRFS_DIR_INDEX_KEY;
 933
 934         while (ret == 0) {
 935                 struct btrfs_delayed_item *item;
 936
 937                 mutex_lock(&node->mutex);
 938                 item = __btrfs_first_delayed_deletion_item(node);
 939                 if (!item) {
 940                         mutex_unlock(&node->mutex);
 941                         break;
 942                 }
 943
 944                 key.offset = item->index;
 945                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 946                 if (ret > 0) {
 947                         /*
 948                          * There's no matching item in the leaf. This means we
 949                          * have already deleted this item in a past run of the
 950                          * delayed items. We ignore errors when running delayed
 951                          * items from an async context, through a work queue job
 952                          * running btrfs_async_run_delayed_root(), and don't
 953                          * release delayed items that failed to complete. This
 954                          * is because we will retry later, and at transaction
 955                          * commit time we always run delayed items and will
 956                          * then deal with errors if they fail to run again.
 957                          *
 958                          * So just release delayed items for which we can't find
 959                          * an item in the tree, and move to the next item.
 960                          */
 961                         btrfs_release_path(path);
 962                         btrfs_release_delayed_item(item);
 963                         ret = 0;
 964                 } else if (ret == 0) {
 965                         ret = btrfs_batch_delete_items(trans, root, path, item);
 966                         btrfs_release_path(path);
 967                 }
 968
 969                 /*
 970                  * We unlock and relock on each iteration, this is to prevent
 971                  * blocking other tasks for too long while we are being run from
 972                  * the async context (work queue job). Those tasks are typically
 973                  * running system calls like creat/mkdir/rename/unlink/etc which
 974                  * need to add delayed items to this delayed node.
 975                  */
 976                 mutex_unlock(&node->mutex);
 977         }
 978
 979         return ret;
 980 }
 981
 982 static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
 983 {
 984         struct btrfs_delayed_root *delayed_root;
 985
 986         if (delayed_node &&
 987             test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
 988                 ASSERT(delayed_node->root);
 989                 clear_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
 990                 delayed_node->count--;
 991
 992                 delayed_root = delayed_node->root->fs_info->delayed_root;
 993                 finish_one_item(delayed_root);
 994         }
 995 }
 996
 997 static void btrfs_release_delayed_iref(struct btrfs_delayed_node *delayed_node)
 998 {
 999
1000         if (test_and_clear_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags)) {
1001                 struct btrfs_delayed_root *delayed_root;
1002
1003                 ASSERT(delayed_node->root);
1004                 delayed_node->count--;
1005
1006                 delayed_root = delayed_node->root->fs_info->delayed_root;
1007                 finish_one_item(delayed_root);
1008         }
1009 }
1010
1011 static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
1012                                         struct btrfs_root *root,
1013                                         struct btrfs_path *path,
1014                                         struct btrfs_delayed_node *node)
1015 {
1016         struct btrfs_fs_info *fs_info = root->fs_info;
1017         struct btrfs_key key;
1018         struct btrfs_inode_item *inode_item;
1019         struct extent_buffer *leaf;
1020         int mod;
1021         int ret;
1022
1023         key.objectid = node->inode_id;
1024         key.type = BTRFS_INODE_ITEM_KEY;
1025         key.offset = 0;
1026
1027         if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
1028                 mod = -1;
1029         else
1030                 mod = 1;
1031
1032         ret = btrfs_lookup_inode(trans, root, path, &key, mod);
1033         if (ret > 0)
1034                 ret = -ENOENT;
1035         if (ret < 0)
1036                 goto out;
1037
1038         leaf = path->nodes[0];
1039         inode_item = btrfs_item_ptr(leaf, path->slots[0],
1040                                     struct btrfs_inode_item);
1041         write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
1042                             sizeof(struct btrfs_inode_item));
1043         btrfs_mark_buffer_dirty(trans, leaf);
1044
1045         if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
1046                 goto out;
1047
1048         /*
1049          * Now we're going to delete the INODE_REF/EXTREF, which should be the
1050          * only one ref left.  Check if the next item is an INODE_REF/EXTREF.
1051          *
1052          * But if we're the last item already, release and search for the last
1053          * INODE_REF/EXTREF.
1054          */
1055         if (path->slots[0] + 1 >= btrfs_header_nritems(leaf)) {
1056                 key.objectid = node->inode_id;
1057                 key.type = BTRFS_INODE_EXTREF_KEY;
1058                 key.offset = (u64)-1;
1059
1060                 btrfs_release_path(path);
1061                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1062                 if (ret < 0)
1063                         goto err_out;
1064                 ASSERT(ret > 0);
1065                 ASSERT(path->slots[0] > 0);
1066                 ret = 0;
1067                 path->slots[0]--;
1068                 leaf = path->nodes[0];
1069         } else {
1070                 path->slots[0]++;
1071         }
1072         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1073         if (key.objectid != node->inode_id)
1074                 goto out;
1075         if (key.type != BTRFS_INODE_REF_KEY &&
1076             key.type != BTRFS_INODE_EXTREF_KEY)
1077                 goto out;
1078
1079         /*
1080          * Delayed iref deletion is for the inode who has only one link,
1081          * so there is only one iref. The case that several irefs are
1082          * in the same item doesn't exist.
1083          */
1084         ret = btrfs_del_item(trans, root, path);
1085 out:
1086         btrfs_release_delayed_iref(node);
1087         btrfs_release_path(path);
1088 err_out:
1089         btrfs_delayed_inode_release_metadata(fs_info, node, (ret < 0));
1090         btrfs_release_delayed_inode(node);
1091
1092         /*
1093          * If we fail to update the delayed inode we need to abort the
1094          * transaction, because we could leave the inode with the improper
1095          * counts behind.
1096          */
1097         if (ret && ret != -ENOENT)
1098                 btrfs_abort_transaction(trans, ret);
1099
1100         return ret;
1101 }
1102
1103 static inline int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
1104                                              struct btrfs_root *root,
1105                                              struct btrfs_path *path,
1106                                              struct btrfs_delayed_node *node)
1107 {
1108         int ret;
1109
1110         mutex_lock(&node->mutex);
1111         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &node->flags)) {
1112                 mutex_unlock(&node->mutex);
1113                 return 0;
1114         }
1115
1116         ret = __btrfs_update_delayed_inode(trans, root, path, node);
1117         mutex_unlock(&node->mutex);
1118         return ret;
1119 }
1120
1121 static inline int
1122 __btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1123                                    struct btrfs_path *path,
1124                                    struct btrfs_delayed_node *node)
1125 {
1126         int ret;
1127
1128         ret = btrfs_insert_delayed_items(trans, path, node->root, node);
1129         if (ret)
1130                 return ret;
1131
1132         ret = btrfs_delete_delayed_items(trans, path, node->root, node);
1133         if (ret)
1134                 return ret;
1135
1136         ret = btrfs_update_delayed_inode(trans, node->root, path, node);
1137         return ret;
1138 }
1139
1140 /*
1141  * Called when committing the transaction.
1142  * Returns 0 on success.
1143  * Returns < 0 on error and returns with an aborted transaction with any
1144  * outstanding delayed items cleaned up.
1145  */
1146 static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
1147 {
1148         struct btrfs_fs_info *fs_info = trans->fs_info;
1149         struct btrfs_delayed_root *delayed_root;
1150         struct btrfs_delayed_node *curr_node, *prev_node;
1151         struct btrfs_path *path;
1152         struct btrfs_block_rsv *block_rsv;
1153         int ret = 0;
1154         bool count = (nr > 0);
1155
1156         if (TRANS_ABORTED(trans))
1157                 return -EIO;
1158
1159         path = btrfs_alloc_path();
1160         if (!path)
1161                 return -ENOMEM;
1162
1163         block_rsv = trans->block_rsv;
1164         trans->block_rsv = &fs_info->delayed_block_rsv;
1165
1166         delayed_root = fs_info->delayed_root;
1167
1168         curr_node = btrfs_first_delayed_node(delayed_root);
1169         while (curr_node && (!count || nr--)) {
1170                 ret = __btrfs_commit_inode_delayed_items(trans, path,
1171                                                          curr_node);
1172                 if (ret) {
1173                         btrfs_abort_transaction(trans, ret);
1174                         break;
1175                 }
1176
1177                 prev_node = curr_node;
1178                 curr_node = btrfs_next_delayed_node(curr_node);
1179                 /*
1180                  * See the comment below about releasing path before releasing
1181                  * node. If the commit of delayed items was successful the path
1182                  * should always be released, but in case of an error, it may
1183                  * point to locked extent buffers (a leaf at the very least).
1184                  */
1185                 ASSERT(path->nodes[0] == NULL);
1186                 btrfs_release_delayed_node(prev_node);
1187         }
1188
1189         /*
1190          * Release the path to avoid a potential deadlock and lockdep splat when
1191          * releasing the delayed node, as that requires taking the delayed node's
1192          * mutex. If another task starts running delayed items before we take
1193          * the mutex, it will first lock the mutex and then it may try to lock
1194          * the same btree path (leaf).
1195          */
1196         btrfs_free_path(path);
1197
1198         if (curr_node)
1199                 btrfs_release_delayed_node(curr_node);
1200         trans->block_rsv = block_rsv;
1201
1202         return ret;
1203 }
1204
1205 int btrfs_run_delayed_items(struct btrfs_trans_handle *trans)
1206 {
1207         return __btrfs_run_delayed_items(trans, -1);
1208 }
1209
1210 int btrfs_run_delayed_items_nr(struct btrfs_trans_handle *trans, int nr)
1211 {
1212         return __btrfs_run_delayed_items(trans, nr);
1213 }
1214
1215 int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1216                                      struct btrfs_inode *inode)
1217 {
1218         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1219         struct btrfs_path *path;
1220         struct btrfs_block_rsv *block_rsv;
1221         int ret;
1222
1223         if (!delayed_node)
1224                 return 0;
1225
1226         mutex_lock(&delayed_node->mutex);
1227         if (!delayed_node->count) {
1228                 mutex_unlock(&delayed_node->mutex);
1229                 btrfs_release_delayed_node(delayed_node);
1230                 return 0;
1231         }
1232         mutex_unlock(&delayed_node->mutex);
1233
1234         path = btrfs_alloc_path();
1235         if (!path) {
1236                 btrfs_release_delayed_node(delayed_node);
1237                 return -ENOMEM;
1238         }
1239
1240         block_rsv = trans->block_rsv;
1241         trans->block_rsv = &delayed_node->root->fs_info->delayed_block_rsv;
1242
1243         ret = __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1244
1245         btrfs_release_delayed_node(delayed_node);
1246         btrfs_free_path(path);
1247         trans->block_rsv = block_rsv;
1248
1249         return ret;
1250 }
1251
1252 int btrfs_commit_inode_delayed_inode(struct btrfs_inode *inode)
1253 {
1254         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1255         struct btrfs_trans_handle *trans;
1256         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1257         struct btrfs_path *path;
1258         struct btrfs_block_rsv *block_rsv;
1259         int ret;
1260
1261         if (!delayed_node)
1262                 return 0;
1263
1264         mutex_lock(&delayed_node->mutex);
1265         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1266                 mutex_unlock(&delayed_node->mutex);
1267                 btrfs_release_delayed_node(delayed_node);
1268                 return 0;
1269         }
1270         mutex_unlock(&delayed_node->mutex);
1271
1272         trans = btrfs_join_transaction(delayed_node->root);
1273         if (IS_ERR(trans)) {
1274                 ret = PTR_ERR(trans);
1275                 goto out;
1276         }
1277
1278         path = btrfs_alloc_path();
1279         if (!path) {
1280                 ret = -ENOMEM;
1281                 goto trans_out;
1282         }
1283
1284         block_rsv = trans->block_rsv;
1285         trans->block_rsv = &fs_info->delayed_block_rsv;
1286
1287         mutex_lock(&delayed_node->mutex);
1288         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags))
1289                 ret = __btrfs_update_delayed_inode(trans, delayed_node->root,
1290                                                    path, delayed_node);
1291         else
1292                 ret = 0;
1293         mutex_unlock(&delayed_node->mutex);
1294
1295         btrfs_free_path(path);
1296         trans->block_rsv = block_rsv;
1297 trans_out:
1298         btrfs_end_transaction(trans);
1299         btrfs_btree_balance_dirty(fs_info);
1300 out:
1301         btrfs_release_delayed_node(delayed_node);
1302
1303         return ret;
1304 }
1305
1306 void btrfs_remove_delayed_node(struct btrfs_inode *inode)
1307 {
1308         struct btrfs_delayed_node *delayed_node;
1309
1310         delayed_node = READ_ONCE(inode->delayed_node);
1311         if (!delayed_node)
1312                 return;
1313
1314         inode->delayed_node = NULL;
1315         btrfs_release_delayed_node(delayed_node);
1316 }
1317
1318 struct btrfs_async_delayed_work {
1319         struct btrfs_delayed_root *delayed_root;
1320         int nr;
1321         struct btrfs_work work;
1322 };
1323
1324 static void btrfs_async_run_delayed_root(struct btrfs_work *work)
1325 {
1326         struct btrfs_async_delayed_work *async_work;
1327         struct btrfs_delayed_root *delayed_root;
1328         struct btrfs_trans_handle *trans;
1329         struct btrfs_path *path;
1330         struct btrfs_delayed_node *delayed_node = NULL;
1331         struct btrfs_root *root;
1332         struct btrfs_block_rsv *block_rsv;
1333         int total_done = 0;
1334
1335         async_work = container_of(work, struct btrfs_async_delayed_work, work);
1336         delayed_root = async_work->delayed_root;
1337
1338         path = btrfs_alloc_path();
1339         if (!path)
1340                 goto out;
1341
1342         do {
1343                 if (atomic_read(&delayed_root->items) <
1344                     BTRFS_DELAYED_BACKGROUND / 2)
1345                         break;
1346
1347                 delayed_node = btrfs_first_prepared_delayed_node(delayed_root);
1348                 if (!delayed_node)
1349                         break;
1350
1351                 root = delayed_node->root;
1352
1353                 trans = btrfs_join_transaction(root);
1354                 if (IS_ERR(trans)) {
1355                         btrfs_release_path(path);
1356                         btrfs_release_prepared_delayed_node(delayed_node);
1357                         total_done++;
1358                         continue;
1359                 }
1360
1361                 block_rsv = trans->block_rsv;
1362                 trans->block_rsv = &root->fs_info->delayed_block_rsv;
1363
1364                 __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1365
1366                 trans->block_rsv = block_rsv;
1367                 btrfs_end_transaction(trans);
1368                 btrfs_btree_balance_dirty_nodelay(root->fs_info);
1369
1370                 btrfs_release_path(path);
1371                 btrfs_release_prepared_delayed_node(delayed_node);
1372                 total_done++;
1373
1374         } while ((async_work->nr == 0 && total_done < BTRFS_DELAYED_WRITEBACK)
1375                  || total_done < async_work->nr);
1376
1377         btrfs_free_path(path);
1378 out:
1379         wake_up(&delayed_root->wait);
1380         kfree(async_work);
1381 }
1382
1383
1384 static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
1385                                      struct btrfs_fs_info *fs_info, int nr)
1386 {
1387         struct btrfs_async_delayed_work *async_work;
1388
1389         async_work = kmalloc(sizeof(*async_work), GFP_NOFS);
1390         if (!async_work)
1391                 return -ENOMEM;
1392
1393         async_work->delayed_root = delayed_root;
1394         btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root, NULL);
1395         async_work->nr = nr;
1396
1397         btrfs_queue_work(fs_info->delayed_workers, &async_work->work);
1398         return 0;
1399 }
1400
1401 void btrfs_assert_delayed_root_empty(struct btrfs_fs_info *fs_info)
1402 {
1403         WARN_ON(btrfs_first_delayed_node(fs_info->delayed_root));
1404 }
1405
1406 static int could_end_wait(struct btrfs_delayed_root *delayed_root, int seq)
1407 {
1408         int val = atomic_read(&delayed_root->items_seq);
1409
1410         if (val < seq || val >= seq + BTRFS_DELAYED_BATCH)
1411                 return 1;
1412
1413         if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
1414                 return 1;
1415
1416         return 0;
1417 }
1418
1419 void btrfs_balance_delayed_items(struct btrfs_fs_info *fs_info)
1420 {
1421         struct btrfs_delayed_root *delayed_root = fs_info->delayed_root;
1422
1423         if ((atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND) ||
1424                 btrfs_workqueue_normal_congested(fs_info->delayed_workers))
1425                 return;
1426
1427         if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
1428                 int seq;
1429                 int ret;
1430
1431                 seq = atomic_read(&delayed_root->items_seq);
1432
1433                 ret = btrfs_wq_run_delayed_node(delayed_root, fs_info, 0);
1434                 if (ret)
1435                         return;
1436
1437                 wait_event_interruptible(delayed_root->wait,
1438                                          could_end_wait(delayed_root, seq));
1439                 return;
1440         }
1441
1442         btrfs_wq_run_delayed_node(delayed_root, fs_info, BTRFS_DELAYED_BATCH);
1443 }
1444
1445 static void btrfs_release_dir_index_item_space(struct btrfs_trans_handle *trans)
1446 {
1447         struct btrfs_fs_info *fs_info = trans->fs_info;
1448         const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
1449
1450         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
1451                 return;
1452
1453         /*
1454          * Adding the new dir index item does not require touching another
1455          * leaf, so we can release 1 unit of metadata that was previously
1456          * reserved when starting the transaction. This applies only to
1457          * the case where we had a transaction start and excludes the
1458          * transaction join case (when replaying log trees).
1459          */
1460         trace_btrfs_space_reservation(fs_info, "transaction",
1461                                       trans->transid, bytes, 0);
1462         btrfs_block_rsv_release(fs_info, trans->block_rsv, bytes, NULL);
1463         ASSERT(trans->bytes_reserved >= bytes);
1464         trans->bytes_reserved -= bytes;
1465 }
1466
1467 /* Will return 0, -ENOMEM or -EEXIST (index number collision, unexpected). */
1468 int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
1469                                    const char *name, int name_len,
1470                                    struct btrfs_inode *dir,
1471                                    struct btrfs_disk_key *disk_key, u8 flags,
1472                                    u64 index)
1473 {
1474         struct btrfs_fs_info *fs_info = trans->fs_info;
1475         const unsigned int leaf_data_size = BTRFS_LEAF_DATA_SIZE(fs_info);
1476         struct btrfs_delayed_node *delayed_node;
1477         struct btrfs_delayed_item *delayed_item;
1478         struct btrfs_dir_item *dir_item;
1479         bool reserve_leaf_space;
1480         u32 data_len;
1481         int ret;
1482
1483         delayed_node = btrfs_get_or_create_delayed_node(dir);
1484         if (IS_ERR(delayed_node))
1485                 return PTR_ERR(delayed_node);
1486
1487         delayed_item = btrfs_alloc_delayed_item(sizeof(*dir_item) + name_len,
1488                                                 delayed_node,
1489                                                 BTRFS_DELAYED_INSERTION_ITEM);
1490         if (!delayed_item) {
1491                 ret = -ENOMEM;
1492                 goto release_node;
1493         }
1494
1495         delayed_item->index = index;
1496
1497         dir_item = (struct btrfs_dir_item *)delayed_item->data;
1498         dir_item->location = *disk_key;
1499         btrfs_set_stack_dir_transid(dir_item, trans->transid);
1500         btrfs_set_stack_dir_data_len(dir_item, 0);
1501         btrfs_set_stack_dir_name_len(dir_item, name_len);
1502         btrfs_set_stack_dir_flags(dir_item, flags);
1503         memcpy((char *)(dir_item + 1), name, name_len);
1504
1505         data_len = delayed_item->data_len + sizeof(struct btrfs_item);
1506
1507         mutex_lock(&delayed_node->mutex);
1508
1509         /*
1510          * First attempt to insert the delayed item. This is to make the error
1511          * handling path simpler in case we fail (-EEXIST). There's no risk of
1512          * any other task coming in and running the delayed item before we do
1513          * the metadata space reservation below, because we are holding the
1514          * delayed node's mutex and that mutex must also be locked before the
1515          * node's delayed items can be run.
1516          */
1517         ret = __btrfs_add_delayed_item(delayed_node, delayed_item);
1518         if (unlikely(ret)) {
1519                 btrfs_err(trans->fs_info,
1520 "error adding delayed dir index item, name: %.*s, index: %llu, root: %llu, dir: %llu, dir->index_cnt: %llu, delayed_node->index_cnt: %llu, error: %d",
1521                           name_len, name, index, btrfs_root_id(delayed_node->root),
1522                           delayed_node->inode_id, dir->index_cnt,
1523                           delayed_node->index_cnt, ret);
1524                 btrfs_release_delayed_item(delayed_item);
1525                 btrfs_release_dir_index_item_space(trans);
1526                 mutex_unlock(&delayed_node->mutex);
1527                 goto release_node;
1528         }
1529
1530         if (delayed_node->index_item_leaves == 0 ||
1531             delayed_node->curr_index_batch_size + data_len > leaf_data_size) {
1532                 delayed_node->curr_index_batch_size = data_len;
1533                 reserve_leaf_space = true;
1534         } else {
1535                 delayed_node->curr_index_batch_size += data_len;
1536                 reserve_leaf_space = false;
1537         }
1538
1539         if (reserve_leaf_space) {
1540                 ret = btrfs_delayed_item_reserve_metadata(trans, delayed_item);
1541                 /*
1542                  * Space was reserved for a dir index item insertion when we
1543                  * started the transaction, so getting a failure here should be
1544                  * impossible.
1545                  */
1546                 if (WARN_ON(ret)) {
1547                         btrfs_release_delayed_item(delayed_item);
1548                         mutex_unlock(&delayed_node->mutex);
1549                         goto release_node;
1550                 }
1551
1552                 delayed_node->index_item_leaves++;
1553         } else {
1554                 btrfs_release_dir_index_item_space(trans);
1555         }
1556         mutex_unlock(&delayed_node->mutex);
1557
1558 release_node:
1559         btrfs_release_delayed_node(delayed_node);
1560         return ret;
1561 }
1562
1563 static int btrfs_delete_delayed_insertion_item(struct btrfs_fs_info *fs_info,
1564                                                struct btrfs_delayed_node *node,
1565                                                u64 index)
1566 {
1567         struct btrfs_delayed_item *item;
1568
1569         mutex_lock(&node->mutex);
1570         item = __btrfs_lookup_delayed_item(&node->ins_root.rb_root, index);
1571         if (!item) {
1572                 mutex_unlock(&node->mutex);
1573                 return 1;
1574         }
1575
1576         /*
1577          * For delayed items to insert, we track reserved metadata bytes based
1578          * on the number of leaves that we will use.
1579          * See btrfs_insert_delayed_dir_index() and
1580          * btrfs_delayed_item_reserve_metadata()).
1581          */
1582         ASSERT(item->bytes_reserved == 0);
1583         ASSERT(node->index_item_leaves > 0);
1584
1585         /*
1586          * If there's only one leaf reserved, we can decrement this item from the
1587          * current batch, otherwise we can not because we don't know which leaf
1588          * it belongs to. With the current limit on delayed items, we rarely
1589          * accumulate enough dir index items to fill more than one leaf (even
1590          * when using a leaf size of 4K).
1591          */
1592         if (node->index_item_leaves == 1) {
1593                 const u32 data_len = item->data_len + sizeof(struct btrfs_item);
1594
1595                 ASSERT(node->curr_index_batch_size >= data_len);
1596                 node->curr_index_batch_size -= data_len;
1597         }
1598
1599         btrfs_release_delayed_item(item);
1600
1601         /* If we now have no more dir index items, we can release all leaves. */
1602         if (RB_EMPTY_ROOT(&node->ins_root.rb_root)) {
1603                 btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
1604                 node->index_item_leaves = 0;
1605         }
1606
1607         mutex_unlock(&node->mutex);
1608         return 0;
1609 }
1610
1611 int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
1612                                    struct btrfs_inode *dir, u64 index)
1613 {
1614         struct btrfs_delayed_node *node;
1615         struct btrfs_delayed_item *item;
1616         int ret;
1617
1618         node = btrfs_get_or_create_delayed_node(dir);
1619         if (IS_ERR(node))
1620                 return PTR_ERR(node);
1621
1622         ret = btrfs_delete_delayed_insertion_item(trans->fs_info, node, index);
1623         if (!ret)
1624                 goto end;
1625
1626         item = btrfs_alloc_delayed_item(0, node, BTRFS_DELAYED_DELETION_ITEM);
1627         if (!item) {
1628                 ret = -ENOMEM;
1629                 goto end;
1630         }
1631
1632         item->index = index;
1633
1634         ret = btrfs_delayed_item_reserve_metadata(trans, item);
1635         /*
1636          * we have reserved enough space when we start a new transaction,
1637          * so reserving metadata failure is impossible.
1638          */
1639         if (ret < 0) {
1640                 btrfs_err(trans->fs_info,
1641 "metadata reservation failed for delayed dir item deltiona, should have been reserved");
1642                 btrfs_release_delayed_item(item);
1643                 goto end;
1644         }
1645
1646         mutex_lock(&node->mutex);
1647         ret = __btrfs_add_delayed_item(node, item);
1648         if (unlikely(ret)) {
1649                 btrfs_err(trans->fs_info,
1650                           "err add delayed dir index item(index: %llu) into the deletion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
1651                           index, node->root->root_key.objectid,
1652                           node->inode_id, ret);
1653                 btrfs_delayed_item_release_metadata(dir->root, item);
1654                 btrfs_release_delayed_item(item);
1655         }
1656         mutex_unlock(&node->mutex);
1657 end:
1658         btrfs_release_delayed_node(node);
1659         return ret;
1660 }
1661
1662 int btrfs_inode_delayed_dir_index_count(struct btrfs_inode *inode)
1663 {
1664         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1665
1666         if (!delayed_node)
1667                 return -ENOENT;
1668
1669         /*
1670          * Since we have held i_mutex of this directory, it is impossible that
1671          * a new directory index is added into the delayed node and index_cnt
1672          * is updated now. So we needn't lock the delayed node.
1673          */
1674         if (!delayed_node->index_cnt) {
1675                 btrfs_release_delayed_node(delayed_node);
1676                 return -EINVAL;
1677         }
1678
1679         inode->index_cnt = delayed_node->index_cnt;
1680         btrfs_release_delayed_node(delayed_node);
1681         return 0;
1682 }
1683
1684 bool btrfs_readdir_get_delayed_items(struct inode *inode,
1685                                      u64 last_index,
1686                                      struct list_head *ins_list,
1687                                      struct list_head *del_list)
1688 {
1689         struct btrfs_delayed_node *delayed_node;
1690         struct btrfs_delayed_item *item;
1691
1692         delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1693         if (!delayed_node)
1694                 return false;
1695
1696         /*
1697          * We can only do one readdir with delayed items at a time because of
1698          * item->readdir_list.
1699          */
1700         btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
1701         btrfs_inode_lock(BTRFS_I(inode), 0);
1702
1703         mutex_lock(&delayed_node->mutex);
1704         item = __btrfs_first_delayed_insertion_item(delayed_node);
1705         while (item && item->index <= last_index) {
1706                 refcount_inc(&item->refs);
1707                 list_add_tail(&item->readdir_list, ins_list);
1708                 item = __btrfs_next_delayed_item(item);
1709         }
1710
1711         item = __btrfs_first_delayed_deletion_item(delayed_node);
1712         while (item && item->index <= last_index) {
1713                 refcount_inc(&item->refs);
1714                 list_add_tail(&item->readdir_list, del_list);
1715                 item = __btrfs_next_delayed_item(item);
1716         }
1717         mutex_unlock(&delayed_node->mutex);
1718         /*
1719          * This delayed node is still cached in the btrfs inode, so refs
1720          * must be > 1 now, and we needn't check it is going to be freed
1721          * or not.
1722          *
1723          * Besides that, this function is used to read dir, we do not
1724          * insert/delete delayed items in this period. So we also needn't
1725          * requeue or dequeue this delayed node.
1726          */
1727         refcount_dec(&delayed_node->refs);
1728
1729         return true;
1730 }
1731
1732 void btrfs_readdir_put_delayed_items(struct inode *inode,
1733                                      struct list_head *ins_list,
1734                                      struct list_head *del_list)
1735 {
1736         struct btrfs_delayed_item *curr, *next;
1737
1738         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1739                 list_del(&curr->readdir_list);
1740                 if (refcount_dec_and_test(&curr->refs))
1741                         kfree(curr);
1742         }
1743
1744         list_for_each_entry_safe(curr, next, del_list, readdir_list) {
1745                 list_del(&curr->readdir_list);
1746                 if (refcount_dec_and_test(&curr->refs))
1747                         kfree(curr);
1748         }
1749
1750         /*
1751          * The VFS is going to do up_read(), so we need to downgrade back to a
1752          * read lock.
1753          */
1754         downgrade_write(&inode->i_rwsem);
1755 }
1756
1757 int btrfs_should_delete_dir_index(struct list_head *del_list,
1758                                   u64 index)
1759 {
1760         struct btrfs_delayed_item *curr;
1761         int ret = 0;
1762
1763         list_for_each_entry(curr, del_list, readdir_list) {
1764                 if (curr->index > index)
1765                         break;
1766                 if (curr->index == index) {
1767                         ret = 1;
1768                         break;
1769                 }
1770         }
1771         return ret;
1772 }
1773
1774 /*
1775  * Read dir info stored in the delayed tree.
1776  */
1777 int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
1778                                     struct list_head *ins_list)
1779 {
1780         struct btrfs_dir_item *di;
1781         struct btrfs_delayed_item *curr, *next;
1782         struct btrfs_key location;
1783         char *name;
1784         int name_len;
1785         int over = 0;
1786         unsigned char d_type;
1787
1788         /*
1789          * Changing the data of the delayed item is impossible. So
1790          * we needn't lock them. And we have held i_mutex of the
1791          * directory, nobody can delete any directory indexes now.
1792          */
1793         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1794                 list_del(&curr->readdir_list);
1795
1796                 if (curr->index < ctx->pos) {
1797                         if (refcount_dec_and_test(&curr->refs))
1798                                 kfree(curr);
1799                         continue;
1800                 }
1801
1802                 ctx->pos = curr->index;
1803
1804                 di = (struct btrfs_dir_item *)curr->data;
1805                 name = (char *)(di + 1);
1806                 name_len = btrfs_stack_dir_name_len(di);
1807
1808                 d_type = fs_ftype_to_dtype(btrfs_dir_flags_to_ftype(di->type));
1809                 btrfs_disk_key_to_cpu(&location, &di->location);
1810
1811                 over = !dir_emit(ctx, name, name_len,
1812                                location.objectid, d_type);
1813
1814                 if (refcount_dec_and_test(&curr->refs))
1815                         kfree(curr);
1816
1817                 if (over)
1818                         return 1;
1819                 ctx->pos++;
1820         }
1821         return 0;
1822 }
1823
1824 static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
1825                                   struct btrfs_inode_item *inode_item,
1826                                   struct inode *inode)
1827 {
1828         u64 flags;
1829
1830         btrfs_set_stack_inode_uid(inode_item, i_uid_read(inode));
1831         btrfs_set_stack_inode_gid(inode_item, i_gid_read(inode));
1832         btrfs_set_stack_inode_size(inode_item, BTRFS_I(inode)->disk_i_size);
1833         btrfs_set_stack_inode_mode(inode_item, inode->i_mode);
1834         btrfs_set_stack_inode_nlink(inode_item, inode->i_nlink);
1835         btrfs_set_stack_inode_nbytes(inode_item, inode_get_bytes(inode));
1836         btrfs_set_stack_inode_generation(inode_item,
1837                                          BTRFS_I(inode)->generation);
1838         btrfs_set_stack_inode_sequence(inode_item,
1839                                        inode_peek_iversion(inode));
1840         btrfs_set_stack_inode_transid(inode_item, trans->transid);
1841         btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
1842         flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
1843                                           BTRFS_I(inode)->ro_flags);
1844         btrfs_set_stack_inode_flags(inode_item, flags);
1845         btrfs_set_stack_inode_block_group(inode_item, 0);
1846
1847         btrfs_set_stack_timespec_sec(&inode_item->atime,
1848                                      inode_get_atime_sec(inode));
1849         btrfs_set_stack_timespec_nsec(&inode_item->atime,
1850                                       inode_get_atime_nsec(inode));
1851
1852         btrfs_set_stack_timespec_sec(&inode_item->mtime,
1853                                      inode_get_mtime_sec(inode));
1854         btrfs_set_stack_timespec_nsec(&inode_item->mtime,
1855                                       inode_get_mtime_nsec(inode));
1856
1857         btrfs_set_stack_timespec_sec(&inode_item->ctime,
1858                                      inode_get_ctime_sec(inode));
1859         btrfs_set_stack_timespec_nsec(&inode_item->ctime,
1860                                       inode_get_ctime_nsec(inode));
1861
1862         btrfs_set_stack_timespec_sec(&inode_item->otime, BTRFS_I(inode)->i_otime_sec);
1863         btrfs_set_stack_timespec_nsec(&inode_item->otime, BTRFS_I(inode)->i_otime_nsec);
1864 }
1865
1866 int btrfs_fill_inode(struct inode *inode, u32 *rdev)
1867 {
1868         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1869         struct btrfs_delayed_node *delayed_node;
1870         struct btrfs_inode_item *inode_item;
1871
1872         delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1873         if (!delayed_node)
1874                 return -ENOENT;
1875
1876         mutex_lock(&delayed_node->mutex);
1877         if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1878                 mutex_unlock(&delayed_node->mutex);
1879                 btrfs_release_delayed_node(delayed_node);
1880                 return -ENOENT;
1881         }
1882
1883         inode_item = &delayed_node->inode_item;
1884
1885         i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
1886         i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
1887         btrfs_i_size_write(BTRFS_I(inode), btrfs_stack_inode_size(inode_item));
1888         btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
1889                         round_up(i_size_read(inode), fs_info->sectorsize));
1890         inode->i_mode = btrfs_stack_inode_mode(inode_item);
1891         set_nlink(inode, btrfs_stack_inode_nlink(inode_item));
1892         inode_set_bytes(inode, btrfs_stack_inode_nbytes(inode_item));
1893         BTRFS_I(inode)->generation = btrfs_stack_inode_generation(inode_item);
1894         BTRFS_I(inode)->last_trans = btrfs_stack_inode_transid(inode_item);
1895
1896         inode_set_iversion_queried(inode,
1897                                    btrfs_stack_inode_sequence(inode_item));
1898         inode->i_rdev = 0;
1899         *rdev = btrfs_stack_inode_rdev(inode_item);
1900         btrfs_inode_split_flags(btrfs_stack_inode_flags(inode_item),
1901                                 &BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags);
1902
1903         inode_set_atime(inode, btrfs_stack_timespec_sec(&inode_item->atime),
1904                         btrfs_stack_timespec_nsec(&inode_item->atime));
1905
1906         inode_set_mtime(inode, btrfs_stack_timespec_sec(&inode_item->mtime),
1907                         btrfs_stack_timespec_nsec(&inode_item->mtime));
1908
1909         inode_set_ctime(inode, btrfs_stack_timespec_sec(&inode_item->ctime),
1910                         btrfs_stack_timespec_nsec(&inode_item->ctime));
1911
1912         BTRFS_I(inode)->i_otime_sec = btrfs_stack_timespec_sec(&inode_item->otime);
1913         BTRFS_I(inode)->i_otime_nsec = btrfs_stack_timespec_nsec(&inode_item->otime);
1914
1915         inode->i_generation = BTRFS_I(inode)->generation;
1916         BTRFS_I(inode)->index_cnt = (u64)-1;
1917
1918         mutex_unlock(&delayed_node->mutex);
1919         btrfs_release_delayed_node(delayed_node);
1920         return 0;
1921 }
1922
1923 int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
1924                                struct btrfs_inode *inode)
1925 {
1926         struct btrfs_root *root = inode->root;
1927         struct btrfs_delayed_node *delayed_node;
1928         int ret = 0;
1929
1930         delayed_node = btrfs_get_or_create_delayed_node(inode);
1931         if (IS_ERR(delayed_node))
1932                 return PTR_ERR(delayed_node);
1933
1934         mutex_lock(&delayed_node->mutex);
1935         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1936                 fill_stack_inode_item(trans, &delayed_node->inode_item,
1937                                       &inode->vfs_inode);
1938                 goto release_node;
1939         }
1940
1941         ret = btrfs_delayed_inode_reserve_metadata(trans, root, delayed_node);
1942         if (ret)
1943                 goto release_node;
1944
1945         fill_stack_inode_item(trans, &delayed_node->inode_item, &inode->vfs_inode);
1946         set_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
1947         delayed_node->count++;
1948         atomic_inc(&root->fs_info->delayed_root->items);
1949 release_node:
1950         mutex_unlock(&delayed_node->mutex);
1951         btrfs_release_delayed_node(delayed_node);
1952         return ret;
1953 }
1954
1955 int btrfs_delayed_delete_inode_ref(struct btrfs_inode *inode)
1956 {
1957         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1958         struct btrfs_delayed_node *delayed_node;
1959
1960         /*
1961          * we don't do delayed inode updates during log recovery because it
1962          * leads to enospc problems.  This means we also can't do
1963          * delayed inode refs
1964          */
1965         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
1966                 return -EAGAIN;
1967
1968         delayed_node = btrfs_get_or_create_delayed_node(inode);
1969         if (IS_ERR(delayed_node))
1970                 return PTR_ERR(delayed_node);
1971
1972         /*
1973          * We don't reserve space for inode ref deletion is because:
1974          * - We ONLY do async inode ref deletion for the inode who has only
1975          *   one link(i_nlink == 1), it means there is only one inode ref.
1976          *   And in most case, the inode ref and the inode item are in the
1977          *   same leaf, and we will deal with them at the same time.
1978          *   Since we are sure we will reserve the space for the inode item,
1979          *   it is unnecessary to reserve space for inode ref deletion.
1980          * - If the inode ref and the inode item are not in the same leaf,
1981          *   We also needn't worry about enospc problem, because we reserve
1982          *   much more space for the inode update than it needs.
1983          * - At the worst, we can steal some space from the global reservation.
1984          *   It is very rare.
1985          */
1986         mutex_lock(&delayed_node->mutex);
1987         if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags))
1988                 goto release_node;
1989
1990         set_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags);
1991         delayed_node->count++;
1992         atomic_inc(&fs_info->delayed_root->items);
1993 release_node:
1994         mutex_unlock(&delayed_node->mutex);
1995         btrfs_release_delayed_node(delayed_node);
1996         return 0;
1997 }
1998
1999 static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
2000 {
2001         struct btrfs_root *root = delayed_node->root;
2002         struct btrfs_fs_info *fs_info = root->fs_info;
2003         struct btrfs_delayed_item *curr_item, *prev_item;
2004
2005         mutex_lock(&delayed_node->mutex);
2006         curr_item = __btrfs_first_delayed_insertion_item(delayed_node);
2007         while (curr_item) {
2008                 prev_item = curr_item;
2009                 curr_item = __btrfs_next_delayed_item(prev_item);
2010                 btrfs_release_delayed_item(prev_item);
2011         }
2012
2013         if (delayed_node->index_item_leaves > 0) {
2014                 btrfs_delayed_item_release_leaves(delayed_node,
2015                                           delayed_node->index_item_leaves);
2016                 delayed_node->index_item_leaves = 0;
2017         }
2018
2019         curr_item = __btrfs_first_delayed_deletion_item(delayed_node);
2020         while (curr_item) {
2021                 btrfs_delayed_item_release_metadata(root, curr_item);
2022                 prev_item = curr_item;
2023                 curr_item = __btrfs_next_delayed_item(prev_item);
2024                 btrfs_release_delayed_item(prev_item);
2025         }
2026
2027         btrfs_release_delayed_iref(delayed_node);
2028
2029         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
2030                 btrfs_delayed_inode_release_metadata(fs_info, delayed_node, false);
2031                 btrfs_release_delayed_inode(delayed_node);
2032         }
2033         mutex_unlock(&delayed_node->mutex);
2034 }
2035
2036 void btrfs_kill_delayed_inode_items(struct btrfs_inode *inode)
2037 {
2038         struct btrfs_delayed_node *delayed_node;
2039
2040         delayed_node = btrfs_get_delayed_node(inode);
2041         if (!delayed_node)
2042                 return;
2043
2044         __btrfs_kill_delayed_node(delayed_node);
2045         btrfs_release_delayed_node(delayed_node);
2046 }
2047
2048 void btrfs_kill_all_delayed_nodes(struct btrfs_root *root)
2049 {
2050         unsigned long index = 0;
2051         struct btrfs_delayed_node *delayed_nodes[8];
2052
2053         while (1) {
2054                 struct btrfs_delayed_node *node;
2055                 int count;
2056
2057                 spin_lock(&root->inode_lock);
2058                 if (xa_empty(&root->delayed_nodes)) {
2059                         spin_unlock(&root->inode_lock);
2060                         return;
2061                 }
2062
2063                 count = 0;
2064                 xa_for_each_start(&root->delayed_nodes, index, node, index) {
2065                         /*
2066                          * Don't increase refs in case the node is dead and
2067                          * about to be removed from the tree in the loop below
2068                          */
2069                         if (refcount_inc_not_zero(&node->refs)) {
2070                                 delayed_nodes[count] = node;
2071                                 count++;
2072                         }
2073                         if (count >= ARRAY_SIZE(delayed_nodes))
2074                                 break;
2075                 }
2076                 spin_unlock(&root->inode_lock);
2077                 index++;
2078
2079                 for (int i = 0; i < count; i++) {
2080                         __btrfs_kill_delayed_node(delayed_nodes[i]);
2081                         btrfs_release_delayed_node(delayed_nodes[i]);
2082                 }
2083         }
2084 }
2085
2086 void btrfs_destroy_delayed_inodes(struct btrfs_fs_info *fs_info)
2087 {
2088         struct btrfs_delayed_node *curr_node, *prev_node;
2089
2090         curr_node = btrfs_first_delayed_node(fs_info->delayed_root);
2091         while (curr_node) {
2092                 __btrfs_kill_delayed_node(curr_node);
2093
2094                 prev_node = curr_node;
2095                 curr_node = btrfs_next_delayed_node(curr_node);
2096                 btrfs_release_delayed_node(prev_node);
2097         }
2098 }
2099
2100 void btrfs_log_get_delayed_items(struct btrfs_inode *inode,
2101                                  struct list_head *ins_list,
2102                                  struct list_head *del_list)
2103 {
2104         struct btrfs_delayed_node *node;
2105         struct btrfs_delayed_item *item;
2106
2107         node = btrfs_get_delayed_node(inode);
2108         if (!node)
2109                 return;
2110
2111         mutex_lock(&node->mutex);
2112         item = __btrfs_first_delayed_insertion_item(node);
2113         while (item) {
2114                 /*
2115                  * It's possible that the item is already in a log list. This
2116                  * can happen in case two tasks are trying to log the same
2117                  * directory. For example if we have tasks A and task B:
2118                  *
2119                  * Task A collected the delayed items into a log list while
2120                  * under the inode's log_mutex (at btrfs_log_inode()), but it
2121                  * only releases the items after logging the inodes they point
2122                  * to (if they are new inodes), which happens after unlocking
2123                  * the log mutex;
2124                  *
2125                  * Task B enters btrfs_log_inode() and acquires the log_mutex
2126                  * of the same directory inode, before task B releases the
2127                  * delayed items. This can happen for example when logging some
2128                  * inode we need to trigger logging of its parent directory, so
2129                  * logging two files that have the same parent directory can
2130                  * lead to this.
2131                  *
2132                  * If this happens, just ignore delayed items already in a log
2133                  * list. All the tasks logging the directory are under a log
2134                  * transaction and whichever finishes first can not sync the log
2135                  * before the other completes and leaves the log transaction.
2136                  */
2137                 if (!item->logged && list_empty(&item->log_list)) {
2138                         refcount_inc(&item->refs);
2139                         list_add_tail(&item->log_list, ins_list);
2140                 }
2141                 item = __btrfs_next_delayed_item(item);
2142         }
2143
2144         item = __btrfs_first_delayed_deletion_item(node);
2145         while (item) {
2146                 /* It may be non-empty, for the same reason mentioned above. */
2147                 if (!item->logged && list_empty(&item->log_list)) {
2148                         refcount_inc(&item->refs);
2149                         list_add_tail(&item->log_list, del_list);
2150                 }
2151                 item = __btrfs_next_delayed_item(item);
2152         }
2153         mutex_unlock(&node->mutex);
2154
2155         /*
2156          * We are called during inode logging, which means the inode is in use
2157          * and can not be evicted before we finish logging the inode. So we never
2158          * have the last reference on the delayed inode.
2159          * Also, we don't use btrfs_release_delayed_node() because that would
2160          * requeue the delayed inode (change its order in the list of prepared
2161          * nodes) and we don't want to do such change because we don't create or
2162          * delete delayed items.
2163          */
2164         ASSERT(refcount_read(&node->refs) > 1);
2165         refcount_dec(&node->refs);
2166 }
2167
2168 void btrfs_log_put_delayed_items(struct btrfs_inode *inode,
2169                                  struct list_head *ins_list,
2170                                  struct list_head *del_list)
2171 {
2172         struct btrfs_delayed_node *node;
2173         struct btrfs_delayed_item *item;
2174         struct btrfs_delayed_item *next;
2175
2176         node = btrfs_get_delayed_node(inode);
2177         if (!node)
2178                 return;
2179
2180         mutex_lock(&node->mutex);
2181
2182         list_for_each_entry_safe(item, next, ins_list, log_list) {
2183                 item->logged = true;
2184                 list_del_init(&item->log_list);
2185                 if (refcount_dec_and_test(&item->refs))
2186                         kfree(item);
2187         }
2188
2189         list_for_each_entry_safe(item, next, del_list, log_list) {
2190                 item->logged = true;
2191                 list_del_init(&item->log_list);
2192                 if (refcount_dec_and_test(&item->refs))
2193                         kfree(item);
2194         }
2195
2196         mutex_unlock(&node->mutex);
2197
2198         /*
2199          * We are called during inode logging, which means the inode is in use
2200          * and can not be evicted before we finish logging the inode. So we never
2201          * have the last reference on the delayed inode.
2202          * Also, we don't use btrfs_release_delayed_node() because that would
2203          * requeue the delayed inode (change its order in the list of prepared
2204          * nodes) and we don't want to do such change because we don't create or
2205          * delete delayed items.
2206          */
2207         ASSERT(refcount_read(&node->refs) > 1);
2208         refcount_dec(&node->refs);
2209 }