fs/btrfs/delayed-ref.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2009 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/slab.h>
   8 #include <linux/sort.h>
   9 #include "ctree.h"
  10 #include "delayed-ref.h"
  11 #include "transaction.h"
  12 #include "qgroup.h"
  13
  14 struct kmem_cache *btrfs_delayed_ref_head_cachep;
  15 struct kmem_cache *btrfs_delayed_tree_ref_cachep;
  16 struct kmem_cache *btrfs_delayed_data_ref_cachep;
  17 struct kmem_cache *btrfs_delayed_extent_op_cachep;
  18 /*
  19  * delayed back reference update tracking.  For subvolume trees
  20  * we queue up extent allocations and backref maintenance for
  21  * delayed processing.   This avoids deep call chains where we
  22  * add extents in the middle of btrfs_search_slot, and it allows
  23  * us to buffer up frequently modified backrefs in an rb tree instead
  24  * of hammering updates on the extent allocation tree.
  25  */
  26
  27 /*
  28  * compare two delayed tree backrefs with same bytenr and type
  29  */
  30 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1,
  31                           struct btrfs_delayed_tree_ref *ref2)
  32 {
  33         if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
  34                 if (ref1->root < ref2->root)
  35                         return -1;
  36                 if (ref1->root > ref2->root)
  37                         return 1;
  38         } else {
  39                 if (ref1->parent < ref2->parent)
  40                         return -1;
  41                 if (ref1->parent > ref2->parent)
  42                         return 1;
  43         }
  44         return 0;
  45 }
  46
  47 /*
  48  * compare two delayed data backrefs with same bytenr and type
  49  */
  50 static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
  51                           struct btrfs_delayed_data_ref *ref2)
  52 {
  53         if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
  54                 if (ref1->root < ref2->root)
  55                         return -1;
  56                 if (ref1->root > ref2->root)
  57                         return 1;
  58                 if (ref1->objectid < ref2->objectid)
  59                         return -1;
  60                 if (ref1->objectid > ref2->objectid)
  61                         return 1;
  62                 if (ref1->offset < ref2->offset)
  63                         return -1;
  64                 if (ref1->offset > ref2->offset)
  65                         return 1;
  66         } else {
  67                 if (ref1->parent < ref2->parent)
  68                         return -1;
  69                 if (ref1->parent > ref2->parent)
  70                         return 1;
  71         }
  72         return 0;
  73 }
  74
  75 static int comp_refs(struct btrfs_delayed_ref_node *ref1,
  76                      struct btrfs_delayed_ref_node *ref2,
  77                      bool check_seq)
  78 {
  79         int ret = 0;
  80
  81         if (ref1->type < ref2->type)
  82                 return -1;
  83         if (ref1->type > ref2->type)
  84                 return 1;
  85         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
  86             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
  87                 ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
  88                                      btrfs_delayed_node_to_tree_ref(ref2));
  89         else
  90                 ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
  91                                      btrfs_delayed_node_to_data_ref(ref2));
  92         if (ret)
  93                 return ret;
  94         if (check_seq) {
  95                 if (ref1->seq < ref2->seq)
  96                         return -1;
  97                 if (ref1->seq > ref2->seq)
  98                         return 1;
  99         }
 100         return 0;
 101 }
 102
 103 /* insert a new ref to head ref rbtree */
 104 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root_cached *root,
 105                                                    struct rb_node *node)
 106 {
 107         struct rb_node **p = &root->rb_root.rb_node;
 108         struct rb_node *parent_node = NULL;
 109         struct btrfs_delayed_ref_head *entry;
 110         struct btrfs_delayed_ref_head *ins;
 111         u64 bytenr;
 112         bool leftmost = true;
 113
 114         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
 115         bytenr = ins->bytenr;
 116         while (*p) {
 117                 parent_node = *p;
 118                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
 119                                  href_node);
 120
 121                 if (bytenr < entry->bytenr) {
 122                         p = &(*p)->rb_left;
 123                 } else if (bytenr > entry->bytenr) {
 124                         p = &(*p)->rb_right;
 125                         leftmost = false;
 126                 } else {
 127                         return entry;
 128                 }
 129         }
 130
 131         rb_link_node(node, parent_node, p);
 132         rb_insert_color_cached(node, root, leftmost);
 133         return NULL;
 134 }
 135
 136 static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root,
 137                 struct btrfs_delayed_ref_node *ins)
 138 {
 139         struct rb_node **p = &root->rb_root.rb_node;
 140         struct rb_node *node = &ins->ref_node;
 141         struct rb_node *parent_node = NULL;
 142         struct btrfs_delayed_ref_node *entry;
 143         bool leftmost = true;
 144
 145         while (*p) {
 146                 int comp;
 147
 148                 parent_node = *p;
 149                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
 150                                  ref_node);
 151                 comp = comp_refs(ins, entry, true);
 152                 if (comp < 0) {
 153                         p = &(*p)->rb_left;
 154                 } else if (comp > 0) {
 155                         p = &(*p)->rb_right;
 156                         leftmost = false;
 157                 } else {
 158                         return entry;
 159                 }
 160         }
 161
 162         rb_link_node(node, parent_node, p);
 163         rb_insert_color_cached(node, root, leftmost);
 164         return NULL;
 165 }
 166
 167 /*
 168  * find an head entry based on bytenr. This returns the delayed ref
 169  * head if it was able to find one, or NULL if nothing was in that spot.
 170  * If return_bigger is given, the next bigger entry is returned if no exact
 171  * match is found.
 172  */
 173 static struct btrfs_delayed_ref_head* find_ref_head(
 174                 struct btrfs_delayed_ref_root *dr, u64 bytenr,
 175                 int return_bigger)
 176 {
 177         struct rb_root *root = &dr->href_root.rb_root;
 178         struct rb_node *n;
 179         struct btrfs_delayed_ref_head *entry;
 180
 181         n = root->rb_node;
 182         entry = NULL;
 183         while (n) {
 184                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
 185
 186                 if (bytenr < entry->bytenr)
 187                         n = n->rb_left;
 188                 else if (bytenr > entry->bytenr)
 189                         n = n->rb_right;
 190                 else
 191                         return entry;
 192         }
 193         if (entry && return_bigger) {
 194                 if (bytenr > entry->bytenr) {
 195                         n = rb_next(&entry->href_node);
 196                         if (!n)
 197                                 n = rb_first_cached(&dr->href_root);
 198                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
 199                                          href_node);
 200                         return entry;
 201                 }
 202                 return entry;
 203         }
 204         return NULL;
 205 }
 206
 207 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 208                            struct btrfs_delayed_ref_head *head)
 209 {
 210         struct btrfs_delayed_ref_root *delayed_refs;
 211
 212         delayed_refs = &trans->transaction->delayed_refs;
 213         lockdep_assert_held(&delayed_refs->lock);
 214         if (mutex_trylock(&head->mutex))
 215                 return 0;
 216
 217         refcount_inc(&head->refs);
 218         spin_unlock(&delayed_refs->lock);
 219
 220         mutex_lock(&head->mutex);
 221         spin_lock(&delayed_refs->lock);
 222         if (RB_EMPTY_NODE(&head->href_node)) {
 223                 mutex_unlock(&head->mutex);
 224                 btrfs_put_delayed_ref_head(head);
 225                 return -EAGAIN;
 226         }
 227         btrfs_put_delayed_ref_head(head);
 228         return 0;
 229 }
 230
 231 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 232                                     struct btrfs_delayed_ref_root *delayed_refs,
 233                                     struct btrfs_delayed_ref_head *head,
 234                                     struct btrfs_delayed_ref_node *ref)
 235 {
 236         lockdep_assert_held(&head->lock);
 237         rb_erase_cached(&ref->ref_node, &head->ref_tree);
 238         RB_CLEAR_NODE(&ref->ref_node);
 239         if (!list_empty(&ref->add_list))
 240                 list_del(&ref->add_list);
 241         ref->in_tree = 0;
 242         btrfs_put_delayed_ref(ref);
 243         atomic_dec(&delayed_refs->num_entries);
 244         if (trans->delayed_ref_updates)
 245                 trans->delayed_ref_updates--;
 246 }
 247
 248 static bool merge_ref(struct btrfs_trans_handle *trans,
 249                       struct btrfs_delayed_ref_root *delayed_refs,
 250                       struct btrfs_delayed_ref_head *head,
 251                       struct btrfs_delayed_ref_node *ref,
 252                       u64 seq)
 253 {
 254         struct btrfs_delayed_ref_node *next;
 255         struct rb_node *node = rb_next(&ref->ref_node);
 256         bool done = false;
 257
 258         while (!done && node) {
 259                 int mod;
 260
 261                 next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
 262                 node = rb_next(node);
 263                 if (seq && next->seq >= seq)
 264                         break;
 265                 if (comp_refs(ref, next, false))
 266                         break;
 267
 268                 if (ref->action == next->action) {
 269                         mod = next->ref_mod;
 270                 } else {
 271                         if (ref->ref_mod < next->ref_mod) {
 272                                 swap(ref, next);
 273                                 done = true;
 274                         }
 275                         mod = -next->ref_mod;
 276                 }
 277
 278                 drop_delayed_ref(trans, delayed_refs, head, next);
 279                 ref->ref_mod += mod;
 280                 if (ref->ref_mod == 0) {
 281                         drop_delayed_ref(trans, delayed_refs, head, ref);
 282                         done = true;
 283                 } else {
 284                         /*
 285                          * Can't have multiples of the same ref on a tree block.
 286                          */
 287                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 288                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 289                 }
 290         }
 291
 292         return done;
 293 }
 294
 295 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 296                               struct btrfs_delayed_ref_root *delayed_refs,
 297                               struct btrfs_delayed_ref_head *head)
 298 {
 299         struct btrfs_fs_info *fs_info = trans->fs_info;
 300         struct btrfs_delayed_ref_node *ref;
 301         struct rb_node *node;
 302         u64 seq = 0;
 303
 304         lockdep_assert_held(&head->lock);
 305
 306         if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
 307                 return;
 308
 309         /* We don't have too many refs to merge for data. */
 310         if (head->is_data)
 311                 return;
 312
 313         spin_lock(&fs_info->tree_mod_seq_lock);
 314         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 315                 struct seq_list *elem;
 316
 317                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 318                                         struct seq_list, list);
 319                 seq = elem->seq;
 320         }
 321         spin_unlock(&fs_info->tree_mod_seq_lock);
 322
 323 again:
 324         for (node = rb_first_cached(&head->ref_tree); node;
 325              node = rb_next(node)) {
 326                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
 327                 if (seq && ref->seq >= seq)
 328                         continue;
 329                 if (merge_ref(trans, delayed_refs, head, ref, seq))
 330                         goto again;
 331         }
 332 }
 333
 334 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq)
 335 {
 336         struct seq_list *elem;
 337         int ret = 0;
 338
 339         spin_lock(&fs_info->tree_mod_seq_lock);
 340         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 341                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 342                                         struct seq_list, list);
 343                 if (seq >= elem->seq) {
 344                         btrfs_debug(fs_info,
 345                                 "holding back delayed_ref %#x.%x, lowest is %#x.%x",
 346                                 (u32)(seq >> 32), (u32)seq,
 347                                 (u32)(elem->seq >> 32), (u32)elem->seq);
 348                         ret = 1;
 349                 }
 350         }
 351
 352         spin_unlock(&fs_info->tree_mod_seq_lock);
 353         return ret;
 354 }
 355
 356 struct btrfs_delayed_ref_head *
 357 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 358 {
 359         struct btrfs_delayed_ref_root *delayed_refs;
 360         struct btrfs_delayed_ref_head *head;
 361         u64 start;
 362         bool loop = false;
 363
 364         delayed_refs = &trans->transaction->delayed_refs;
 365
 366 again:
 367         start = delayed_refs->run_delayed_start;
 368         head = find_ref_head(delayed_refs, start, 1);
 369         if (!head && !loop) {
 370                 delayed_refs->run_delayed_start = 0;
 371                 start = 0;
 372                 loop = true;
 373                 head = find_ref_head(delayed_refs, start, 1);
 374                 if (!head)
 375                         return NULL;
 376         } else if (!head && loop) {
 377                 return NULL;
 378         }
 379
 380         while (head->processing) {
 381                 struct rb_node *node;
 382
 383                 node = rb_next(&head->href_node);
 384                 if (!node) {
 385                         if (loop)
 386                                 return NULL;
 387                         delayed_refs->run_delayed_start = 0;
 388                         start = 0;
 389                         loop = true;
 390                         goto again;
 391                 }
 392                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 393                                 href_node);
 394         }
 395
 396         head->processing = 1;
 397         WARN_ON(delayed_refs->num_heads_ready == 0);
 398         delayed_refs->num_heads_ready--;
 399         delayed_refs->run_delayed_start = head->bytenr +
 400                 head->num_bytes;
 401         return head;
 402 }
 403
 404 /*
 405  * Helper to insert the ref_node to the tail or merge with tail.
 406  *
 407  * Return 0 for insert.
 408  * Return >0 for merge.
 409  */
 410 static int insert_delayed_ref(struct btrfs_trans_handle *trans,
 411                               struct btrfs_delayed_ref_root *root,
 412                               struct btrfs_delayed_ref_head *href,
 413                               struct btrfs_delayed_ref_node *ref)
 414 {
 415         struct btrfs_delayed_ref_node *exist;
 416         int mod;
 417         int ret = 0;
 418
 419         spin_lock(&href->lock);
 420         exist = tree_insert(&href->ref_tree, ref);
 421         if (!exist)
 422                 goto inserted;
 423
 424         /* Now we are sure we can merge */
 425         ret = 1;
 426         if (exist->action == ref->action) {
 427                 mod = ref->ref_mod;
 428         } else {
 429                 /* Need to change action */
 430                 if (exist->ref_mod < ref->ref_mod) {
 431                         exist->action = ref->action;
 432                         mod = -exist->ref_mod;
 433                         exist->ref_mod = ref->ref_mod;
 434                         if (ref->action == BTRFS_ADD_DELAYED_REF)
 435                                 list_add_tail(&exist->add_list,
 436                                               &href->ref_add_list);
 437                         else if (ref->action == BTRFS_DROP_DELAYED_REF) {
 438                                 ASSERT(!list_empty(&exist->add_list));
 439                                 list_del(&exist->add_list);
 440                         } else {
 441                                 ASSERT(0);
 442                         }
 443                 } else
 444                         mod = -ref->ref_mod;
 445         }
 446         exist->ref_mod += mod;
 447
 448         /* remove existing tail if its ref_mod is zero */
 449         if (exist->ref_mod == 0)
 450                 drop_delayed_ref(trans, root, href, exist);
 451         spin_unlock(&href->lock);
 452         return ret;
 453 inserted:
 454         if (ref->action == BTRFS_ADD_DELAYED_REF)
 455                 list_add_tail(&ref->add_list, &href->ref_add_list);
 456         atomic_inc(&root->num_entries);
 457         trans->delayed_ref_updates++;
 458         spin_unlock(&href->lock);
 459         return ret;
 460 }
 461
 462 /*
 463  * helper function to update the accounting in the head ref
 464  * existing and update must have the same bytenr
 465  */
 466 static noinline void
 467 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
 468                          struct btrfs_delayed_ref_head *existing,
 469                          struct btrfs_delayed_ref_head *update,
 470                          int *old_ref_mod_ret)
 471 {
 472         int old_ref_mod;
 473
 474         BUG_ON(existing->is_data != update->is_data);
 475
 476         spin_lock(&existing->lock);
 477         if (update->must_insert_reserved) {
 478                 /* if the extent was freed and then
 479                  * reallocated before the delayed ref
 480                  * entries were processed, we can end up
 481                  * with an existing head ref without
 482                  * the must_insert_reserved flag set.
 483                  * Set it again here
 484                  */
 485                 existing->must_insert_reserved = update->must_insert_reserved;
 486
 487                 /*
 488                  * update the num_bytes so we make sure the accounting
 489                  * is done correctly
 490                  */
 491                 existing->num_bytes = update->num_bytes;
 492
 493         }
 494
 495         if (update->extent_op) {
 496                 if (!existing->extent_op) {
 497                         existing->extent_op = update->extent_op;
 498                 } else {
 499                         if (update->extent_op->update_key) {
 500                                 memcpy(&existing->extent_op->key,
 501                                        &update->extent_op->key,
 502                                        sizeof(update->extent_op->key));
 503                                 existing->extent_op->update_key = true;
 504                         }
 505                         if (update->extent_op->update_flags) {
 506                                 existing->extent_op->flags_to_set |=
 507                                         update->extent_op->flags_to_set;
 508                                 existing->extent_op->update_flags = true;
 509                         }
 510                         btrfs_free_delayed_extent_op(update->extent_op);
 511                 }
 512         }
 513         /*
 514          * update the reference mod on the head to reflect this new operation,
 515          * only need the lock for this case cause we could be processing it
 516          * currently, for refs we just added we know we're a-ok.
 517          */
 518         old_ref_mod = existing->total_ref_mod;
 519         if (old_ref_mod_ret)
 520                 *old_ref_mod_ret = old_ref_mod;
 521         existing->ref_mod += update->ref_mod;
 522         existing->total_ref_mod += update->ref_mod;
 523
 524         /*
 525          * If we are going to from a positive ref mod to a negative or vice
 526          * versa we need to make sure to adjust pending_csums accordingly.
 527          */
 528         if (existing->is_data) {
 529                 if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
 530                         delayed_refs->pending_csums -= existing->num_bytes;
 531                 if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
 532                         delayed_refs->pending_csums += existing->num_bytes;
 533         }
 534         spin_unlock(&existing->lock);
 535 }
 536
 537 static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
 538                                   struct btrfs_qgroup_extent_record *qrecord,
 539                                   u64 bytenr, u64 num_bytes, u64 ref_root,
 540                                   u64 reserved, int action, bool is_data,
 541                                   bool is_system)
 542 {
 543         int count_mod = 1;
 544         int must_insert_reserved = 0;
 545
 546         /* If reserved is provided, it must be a data extent. */
 547         BUG_ON(!is_data && reserved);
 548
 549         /*
 550          * The head node stores the sum of all the mods, so dropping a ref
 551          * should drop the sum in the head node by one.
 552          */
 553         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 554                 count_mod = 0;
 555         else if (action == BTRFS_DROP_DELAYED_REF)
 556                 count_mod = -1;
 557
 558         /*
 559          * BTRFS_ADD_DELAYED_EXTENT means that we need to update the reserved
 560          * accounting when the extent is finally added, or if a later
 561          * modification deletes the delayed ref without ever inserting the
 562          * extent into the extent allocation tree.  ref->must_insert_reserved
 563          * is the flag used to record that accounting mods are required.
 564          *
 565          * Once we record must_insert_reserved, switch the action to
 566          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 567          */
 568         if (action == BTRFS_ADD_DELAYED_EXTENT)
 569                 must_insert_reserved = 1;
 570         else
 571                 must_insert_reserved = 0;
 572
 573         refcount_set(&head_ref->refs, 1);
 574         head_ref->bytenr = bytenr;
 575         head_ref->num_bytes = num_bytes;
 576         head_ref->ref_mod = count_mod;
 577         head_ref->must_insert_reserved = must_insert_reserved;
 578         head_ref->is_data = is_data;
 579         head_ref->is_system = is_system;
 580         head_ref->ref_tree = RB_ROOT_CACHED;
 581         INIT_LIST_HEAD(&head_ref->ref_add_list);
 582         RB_CLEAR_NODE(&head_ref->href_node);
 583         head_ref->processing = 0;
 584         head_ref->total_ref_mod = count_mod;
 585         head_ref->qgroup_reserved = 0;
 586         head_ref->qgroup_ref_root = 0;
 587         spin_lock_init(&head_ref->lock);
 588         mutex_init(&head_ref->mutex);
 589
 590         if (qrecord) {
 591                 if (ref_root && reserved) {
 592                         head_ref->qgroup_ref_root = ref_root;
 593                         head_ref->qgroup_reserved = reserved;
 594                 }
 595
 596                 qrecord->bytenr = bytenr;
 597                 qrecord->num_bytes = num_bytes;
 598                 qrecord->old_roots = NULL;
 599         }
 600 }
 601
 602 /*
 603  * helper function to actually insert a head node into the rbtree.
 604  * this does all the dirty work in terms of maintaining the correct
 605  * overall modification count.
 606  */
 607 static noinline struct btrfs_delayed_ref_head *
 608 add_delayed_ref_head(struct btrfs_trans_handle *trans,
 609                      struct btrfs_delayed_ref_head *head_ref,
 610                      struct btrfs_qgroup_extent_record *qrecord,
 611                      int action, int *qrecord_inserted_ret,
 612                      int *old_ref_mod, int *new_ref_mod)
 613 {
 614         struct btrfs_delayed_ref_head *existing;
 615         struct btrfs_delayed_ref_root *delayed_refs;
 616         int qrecord_inserted = 0;
 617
 618         delayed_refs = &trans->transaction->delayed_refs;
 619
 620         /* Record qgroup extent info if provided */
 621         if (qrecord) {
 622                 if (btrfs_qgroup_trace_extent_nolock(trans->fs_info,
 623                                         delayed_refs, qrecord))
 624                         kfree(qrecord);
 625                 else
 626                         qrecord_inserted = 1;
 627         }
 628
 629         trace_add_delayed_ref_head(trans->fs_info, head_ref, action);
 630
 631         existing = htree_insert(&delayed_refs->href_root,
 632                                 &head_ref->href_node);
 633         if (existing) {
 634                 WARN_ON(qrecord && head_ref->qgroup_ref_root
 635                         && head_ref->qgroup_reserved
 636                         && existing->qgroup_ref_root
 637                         && existing->qgroup_reserved);
 638                 update_existing_head_ref(delayed_refs, existing, head_ref,
 639                                          old_ref_mod);
 640                 /*
 641                  * we've updated the existing ref, free the newly
 642                  * allocated ref
 643                  */
 644                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 645                 head_ref = existing;
 646         } else {
 647                 if (old_ref_mod)
 648                         *old_ref_mod = 0;
 649                 if (head_ref->is_data && head_ref->ref_mod < 0)
 650                         delayed_refs->pending_csums += head_ref->num_bytes;
 651                 delayed_refs->num_heads++;
 652                 delayed_refs->num_heads_ready++;
 653                 atomic_inc(&delayed_refs->num_entries);
 654                 trans->delayed_ref_updates++;
 655         }
 656         if (qrecord_inserted_ret)
 657                 *qrecord_inserted_ret = qrecord_inserted;
 658         if (new_ref_mod)
 659                 *new_ref_mod = head_ref->total_ref_mod;
 660
 661         return head_ref;
 662 }
 663
 664 /*
 665  * init_delayed_ref_common - Initialize the structure which represents a
 666  *                           modification to a an extent.
 667  *
 668  * @fs_info:    Internal to the mounted filesystem mount structure.
 669  *
 670  * @ref:        The structure which is going to be initialized.
 671  *
 672  * @bytenr:     The logical address of the extent for which a modification is
 673  *              going to be recorded.
 674  *
 675  * @num_bytes:  Size of the extent whose modification is being recorded.
 676  *
 677  * @ref_root:   The id of the root where this modification has originated, this
 678  *              can be either one of the well-known metadata trees or the
 679  *              subvolume id which references this extent.
 680  *
 681  * @action:     Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or
 682  *              BTRFS_ADD_DELAYED_EXTENT
 683  *
 684  * @ref_type:   Holds the type of the extent which is being recorded, can be
 685  *              one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY
 686  *              when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/
 687  *              BTRFS_EXTENT_DATA_REF_KEY when recording data extent
 688  */
 689 static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
 690                                     struct btrfs_delayed_ref_node *ref,
 691                                     u64 bytenr, u64 num_bytes, u64 ref_root,
 692                                     int action, u8 ref_type)
 693 {
 694         u64 seq = 0;
 695
 696         if (action == BTRFS_ADD_DELAYED_EXTENT)
 697                 action = BTRFS_ADD_DELAYED_REF;
 698
 699         if (is_fstree(ref_root))
 700                 seq = atomic64_read(&fs_info->tree_mod_seq);
 701
 702         refcount_set(&ref->refs, 1);
 703         ref->bytenr = bytenr;
 704         ref->num_bytes = num_bytes;
 705         ref->ref_mod = 1;
 706         ref->action = action;
 707         ref->is_head = 0;
 708         ref->in_tree = 1;
 709         ref->seq = seq;
 710         ref->type = ref_type;
 711         RB_CLEAR_NODE(&ref->ref_node);
 712         INIT_LIST_HEAD(&ref->add_list);
 713 }
 714
 715 /*
 716  * add a delayed tree ref.  This does all of the accounting required
 717  * to make sure the delayed ref is eventually processed before this
 718  * transaction commits.
 719  */
 720 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 721                                u64 bytenr, u64 num_bytes, u64 parent,
 722                                u64 ref_root,  int level, int action,
 723                                struct btrfs_delayed_extent_op *extent_op,
 724                                int *old_ref_mod, int *new_ref_mod)
 725 {
 726         struct btrfs_fs_info *fs_info = trans->fs_info;
 727         struct btrfs_delayed_tree_ref *ref;
 728         struct btrfs_delayed_ref_head *head_ref;
 729         struct btrfs_delayed_ref_root *delayed_refs;
 730         struct btrfs_qgroup_extent_record *record = NULL;
 731         int qrecord_inserted;
 732         bool is_system = (ref_root == BTRFS_CHUNK_TREE_OBJECTID);
 733         int ret;
 734         u8 ref_type;
 735
 736         BUG_ON(extent_op && extent_op->is_data);
 737         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 738         if (!ref)
 739                 return -ENOMEM;
 740
 741         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 742         if (!head_ref) {
 743                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 744                 return -ENOMEM;
 745         }
 746
 747         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 748             is_fstree(ref_root)) {
 749                 record = kmalloc(sizeof(*record), GFP_NOFS);
 750                 if (!record) {
 751                         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 752                         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 753                         return -ENOMEM;
 754                 }
 755         }
 756
 757         if (parent)
 758                 ref_type = BTRFS_SHARED_BLOCK_REF_KEY;
 759         else
 760                 ref_type = BTRFS_TREE_BLOCK_REF_KEY;
 761
 762         init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
 763                                 ref_root, action, ref_type);
 764         ref->root = ref_root;
 765         ref->parent = parent;
 766         ref->level = level;
 767
 768         init_delayed_ref_head(head_ref, record, bytenr, num_bytes,
 769                               ref_root, 0, action, false, is_system);
 770         head_ref->extent_op = extent_op;
 771
 772         delayed_refs = &trans->transaction->delayed_refs;
 773         spin_lock(&delayed_refs->lock);
 774
 775         /*
 776          * insert both the head node and the new ref without dropping
 777          * the spin lock
 778          */
 779         head_ref = add_delayed_ref_head(trans, head_ref, record,
 780                                         action, &qrecord_inserted,
 781                                         old_ref_mod, new_ref_mod);
 782
 783         ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
 784         spin_unlock(&delayed_refs->lock);
 785
 786         trace_add_delayed_tree_ref(fs_info, &ref->node, ref,
 787                                    action == BTRFS_ADD_DELAYED_EXTENT ?
 788                                    BTRFS_ADD_DELAYED_REF : action);
 789         if (ret > 0)
 790                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 791
 792         if (qrecord_inserted)
 793                 btrfs_qgroup_trace_extent_post(fs_info, record);
 794
 795         return 0;
 796 }
 797
 798 /*
 799  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 800  */
 801 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
 802                                u64 bytenr, u64 num_bytes,
 803                                u64 parent, u64 ref_root,
 804                                u64 owner, u64 offset, u64 reserved, int action,
 805                                int *old_ref_mod, int *new_ref_mod)
 806 {
 807         struct btrfs_fs_info *fs_info = trans->fs_info;
 808         struct btrfs_delayed_data_ref *ref;
 809         struct btrfs_delayed_ref_head *head_ref;
 810         struct btrfs_delayed_ref_root *delayed_refs;
 811         struct btrfs_qgroup_extent_record *record = NULL;
 812         int qrecord_inserted;
 813         int ret;
 814         u8 ref_type;
 815
 816         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 817         if (!ref)
 818                 return -ENOMEM;
 819
 820         if (parent)
 821                 ref_type = BTRFS_SHARED_DATA_REF_KEY;
 822         else
 823                 ref_type = BTRFS_EXTENT_DATA_REF_KEY;
 824         init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
 825                                 ref_root, action, ref_type);
 826         ref->root = ref_root;
 827         ref->parent = parent;
 828         ref->objectid = owner;
 829         ref->offset = offset;
 830
 831
 832         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 833         if (!head_ref) {
 834                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 835                 return -ENOMEM;
 836         }
 837
 838         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 839             is_fstree(ref_root)) {
 840                 record = kmalloc(sizeof(*record), GFP_NOFS);
 841                 if (!record) {
 842                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 843                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
 844                                         head_ref);
 845                         return -ENOMEM;
 846                 }
 847         }
 848
 849         init_delayed_ref_head(head_ref, record, bytenr, num_bytes, ref_root,
 850                               reserved, action, true, false);
 851         head_ref->extent_op = NULL;
 852
 853         delayed_refs = &trans->transaction->delayed_refs;
 854         spin_lock(&delayed_refs->lock);
 855
 856         /*
 857          * insert both the head node and the new ref without dropping
 858          * the spin lock
 859          */
 860         head_ref = add_delayed_ref_head(trans, head_ref, record,
 861                                         action, &qrecord_inserted,
 862                                         old_ref_mod, new_ref_mod);
 863
 864         ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
 865         spin_unlock(&delayed_refs->lock);
 866
 867         trace_add_delayed_data_ref(trans->fs_info, &ref->node, ref,
 868                                    action == BTRFS_ADD_DELAYED_EXTENT ?
 869                                    BTRFS_ADD_DELAYED_REF : action);
 870         if (ret > 0)
 871                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 872
 873
 874         if (qrecord_inserted)
 875                 return btrfs_qgroup_trace_extent_post(fs_info, record);
 876         return 0;
 877 }
 878
 879 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 880                                 struct btrfs_trans_handle *trans,
 881                                 u64 bytenr, u64 num_bytes,
 882                                 struct btrfs_delayed_extent_op *extent_op)
 883 {
 884         struct btrfs_delayed_ref_head *head_ref;
 885         struct btrfs_delayed_ref_root *delayed_refs;
 886
 887         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 888         if (!head_ref)
 889                 return -ENOMEM;
 890
 891         init_delayed_ref_head(head_ref, NULL, bytenr, num_bytes, 0, 0,
 892                               BTRFS_UPDATE_DELAYED_HEAD, extent_op->is_data,
 893                               false);
 894         head_ref->extent_op = extent_op;
 895
 896         delayed_refs = &trans->transaction->delayed_refs;
 897         spin_lock(&delayed_refs->lock);
 898
 899         add_delayed_ref_head(trans, head_ref, NULL, BTRFS_UPDATE_DELAYED_HEAD,
 900                              NULL, NULL, NULL);
 901
 902         spin_unlock(&delayed_refs->lock);
 903         return 0;
 904 }
 905
 906 /*
 907  * this does a simple search for the head node for a given extent.
 908  * It must be called with the delayed ref spinlock held, and it returns
 909  * the head node if any where found, or NULL if not.
 910  */
 911 struct btrfs_delayed_ref_head *
 912 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
 913 {
 914         return find_ref_head(delayed_refs, bytenr, 0);
 915 }
 916
 917 void __cold btrfs_delayed_ref_exit(void)
 918 {
 919         kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 920         kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 921         kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 922         kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 923 }
 924
 925 int __init btrfs_delayed_ref_init(void)
 926 {
 927         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 928                                 "btrfs_delayed_ref_head",
 929                                 sizeof(struct btrfs_delayed_ref_head), 0,
 930                                 SLAB_MEM_SPREAD, NULL);
 931         if (!btrfs_delayed_ref_head_cachep)
 932                 goto fail;
 933
 934         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 935                                 "btrfs_delayed_tree_ref",
 936                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 937                                 SLAB_MEM_SPREAD, NULL);
 938         if (!btrfs_delayed_tree_ref_cachep)
 939                 goto fail;
 940
 941         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 942                                 "btrfs_delayed_data_ref",
 943                                 sizeof(struct btrfs_delayed_data_ref), 0,
 944                                 SLAB_MEM_SPREAD, NULL);
 945         if (!btrfs_delayed_data_ref_cachep)
 946                 goto fail;
 947
 948         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 949                                 "btrfs_delayed_extent_op",
 950                                 sizeof(struct btrfs_delayed_extent_op), 0,
 951                                 SLAB_MEM_SPREAD, NULL);
 952         if (!btrfs_delayed_extent_op_cachep)
 953                 goto fail;
 954
 955         return 0;
 956 fail:
 957         btrfs_delayed_ref_exit();
 958         return -ENOMEM;
 959 }