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