fs/btrfs/delayed-ref.c

   1 /*
   2  * Copyright (C) 2009 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/sort.h>
  22 #include "ctree.h"
  23 #include "delayed-ref.h"
  24 #include "transaction.h"
  25
  26 struct kmem_cache *btrfs_delayed_ref_head_cachep;
  27 struct kmem_cache *btrfs_delayed_tree_ref_cachep;
  28 struct kmem_cache *btrfs_delayed_data_ref_cachep;
  29 struct kmem_cache *btrfs_delayed_extent_op_cachep;
  30 /*
  31  * delayed back reference update tracking.  For subvolume trees
  32  * we queue up extent allocations and backref maintenance for
  33  * delayed processing.   This avoids deep call chains where we
  34  * add extents in the middle of btrfs_search_slot, and it allows
  35  * us to buffer up frequently modified backrefs in an rb tree instead
  36  * of hammering updates on the extent allocation tree.
  37  */
  38
  39 /*
  40  * compare two delayed tree backrefs with same bytenr and type
  41  */
  42 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
  43                           struct btrfs_delayed_tree_ref *ref1, int type)
  44 {
  45         if (type == BTRFS_TREE_BLOCK_REF_KEY) {
  46                 if (ref1->root < ref2->root)
  47                         return -1;
  48                 if (ref1->root > ref2->root)
  49                         return 1;
  50         } else {
  51                 if (ref1->parent < ref2->parent)
  52                         return -1;
  53                 if (ref1->parent > ref2->parent)
  54                         return 1;
  55         }
  56         return 0;
  57 }
  58
  59 /*
  60  * compare two delayed data backrefs with same bytenr and type
  61  */
  62 static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
  63                           struct btrfs_delayed_data_ref *ref1)
  64 {
  65         if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
  66                 if (ref1->root < ref2->root)
  67                         return -1;
  68                 if (ref1->root > ref2->root)
  69                         return 1;
  70                 if (ref1->objectid < ref2->objectid)
  71                         return -1;
  72                 if (ref1->objectid > ref2->objectid)
  73                         return 1;
  74                 if (ref1->offset < ref2->offset)
  75                         return -1;
  76                 if (ref1->offset > ref2->offset)
  77                         return 1;
  78         } else {
  79                 if (ref1->parent < ref2->parent)
  80                         return -1;
  81                 if (ref1->parent > ref2->parent)
  82                         return 1;
  83         }
  84         return 0;
  85 }
  86
  87 /*
  88  * entries in the rb tree are ordered by the byte number of the extent,
  89  * type of the delayed backrefs and content of delayed backrefs.
  90  */
  91 static int comp_entry(struct btrfs_delayed_ref_node *ref2,
  92                       struct btrfs_delayed_ref_node *ref1,
  93                       bool compare_seq)
  94 {
  95         if (ref1->bytenr < ref2->bytenr)
  96                 return -1;
  97         if (ref1->bytenr > ref2->bytenr)
  98                 return 1;
  99         if (ref1->is_head && ref2->is_head)
 100                 return 0;
 101         if (ref2->is_head)
 102                 return -1;
 103         if (ref1->is_head)
 104                 return 1;
 105         if (ref1->type < ref2->type)
 106                 return -1;
 107         if (ref1->type > ref2->type)
 108                 return 1;
 109         if (ref1->no_quota > ref2->no_quota)
 110                 return 1;
 111         if (ref1->no_quota < ref2->no_quota)
 112                 return -1;
 113         /* merging of sequenced refs is not allowed */
 114         if (compare_seq) {
 115                 if (ref1->seq < ref2->seq)
 116                         return -1;
 117                 if (ref1->seq > ref2->seq)
 118                         return 1;
 119         }
 120         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
 121             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
 122                 return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
 123                                       btrfs_delayed_node_to_tree_ref(ref1),
 124                                       ref1->type);
 125         } else if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY ||
 126                    ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
 127                 return comp_data_refs(btrfs_delayed_node_to_data_ref(ref2),
 128                                       btrfs_delayed_node_to_data_ref(ref1));
 129         }
 130         BUG();
 131         return 0;
 132 }
 133
 134 /*
 135  * insert a new ref into the rbtree.  This returns any existing refs
 136  * for the same (bytenr,parent) tuple, or NULL if the new node was properly
 137  * inserted.
 138  */
 139 static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
 140                                                   struct rb_node *node)
 141 {
 142         struct rb_node **p = &root->rb_node;
 143         struct rb_node *parent_node = NULL;
 144         struct btrfs_delayed_ref_node *entry;
 145         struct btrfs_delayed_ref_node *ins;
 146         int cmp;
 147
 148         ins = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 149         while (*p) {
 150                 parent_node = *p;
 151                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
 152                                  rb_node);
 153
 154                 cmp = comp_entry(entry, ins, 1);
 155                 if (cmp < 0)
 156                         p = &(*p)->rb_left;
 157                 else if (cmp > 0)
 158                         p = &(*p)->rb_right;
 159                 else
 160                         return entry;
 161         }
 162
 163         rb_link_node(node, parent_node, p);
 164         rb_insert_color(node, root);
 165         return NULL;
 166 }
 167
 168 /* insert a new ref to head ref rbtree */
 169 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
 170                                                    struct rb_node *node)
 171 {
 172         struct rb_node **p = &root->rb_node;
 173         struct rb_node *parent_node = NULL;
 174         struct btrfs_delayed_ref_head *entry;
 175         struct btrfs_delayed_ref_head *ins;
 176         u64 bytenr;
 177
 178         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
 179         bytenr = ins->node.bytenr;
 180         while (*p) {
 181                 parent_node = *p;
 182                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
 183                                  href_node);
 184
 185                 if (bytenr < entry->node.bytenr)
 186                         p = &(*p)->rb_left;
 187                 else if (bytenr > entry->node.bytenr)
 188                         p = &(*p)->rb_right;
 189                 else
 190                         return entry;
 191         }
 192
 193         rb_link_node(node, parent_node, p);
 194         rb_insert_color(node, root);
 195         return NULL;
 196 }
 197
 198 /*
 199  * find an head entry based on bytenr. This returns the delayed ref
 200  * head if it was able to find one, or NULL if nothing was in that spot.
 201  * If return_bigger is given, the next bigger entry is returned if no exact
 202  * match is found.
 203  */
 204 static struct btrfs_delayed_ref_head *
 205 find_ref_head(struct rb_root *root, u64 bytenr,
 206               int return_bigger)
 207 {
 208         struct rb_node *n;
 209         struct btrfs_delayed_ref_head *entry;
 210
 211         n = root->rb_node;
 212         entry = NULL;
 213         while (n) {
 214                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
 215
 216                 if (bytenr < entry->node.bytenr)
 217                         n = n->rb_left;
 218                 else if (bytenr > entry->node.bytenr)
 219                         n = n->rb_right;
 220                 else
 221                         return entry;
 222         }
 223         if (entry && return_bigger) {
 224                 if (bytenr > entry->node.bytenr) {
 225                         n = rb_next(&entry->href_node);
 226                         if (!n)
 227                                 n = rb_first(root);
 228                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
 229                                          href_node);
 230                         return entry;
 231                 }
 232                 return entry;
 233         }
 234         return NULL;
 235 }
 236
 237 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 238                            struct btrfs_delayed_ref_head *head)
 239 {
 240         struct btrfs_delayed_ref_root *delayed_refs;
 241
 242         delayed_refs = &trans->transaction->delayed_refs;
 243         assert_spin_locked(&delayed_refs->lock);
 244         if (mutex_trylock(&head->mutex))
 245                 return 0;
 246
 247         atomic_inc(&head->node.refs);
 248         spin_unlock(&delayed_refs->lock);
 249
 250         mutex_lock(&head->mutex);
 251         spin_lock(&delayed_refs->lock);
 252         if (!head->node.in_tree) {
 253                 mutex_unlock(&head->mutex);
 254                 btrfs_put_delayed_ref(&head->node);
 255                 return -EAGAIN;
 256         }
 257         btrfs_put_delayed_ref(&head->node);
 258         return 0;
 259 }
 260
 261 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 262                                     struct btrfs_delayed_ref_root *delayed_refs,
 263                                     struct btrfs_delayed_ref_head *head,
 264                                     struct btrfs_delayed_ref_node *ref)
 265 {
 266         if (btrfs_delayed_ref_is_head(ref)) {
 267                 head = btrfs_delayed_node_to_head(ref);
 268                 rb_erase(&head->href_node, &delayed_refs->href_root);
 269         } else {
 270                 assert_spin_locked(&head->lock);
 271                 rb_erase(&ref->rb_node, &head->ref_root);
 272         }
 273         ref->in_tree = 0;
 274         btrfs_put_delayed_ref(ref);
 275         atomic_dec(&delayed_refs->num_entries);
 276         if (trans->delayed_ref_updates)
 277                 trans->delayed_ref_updates--;
 278 }
 279
 280 static int merge_ref(struct btrfs_trans_handle *trans,
 281                      struct btrfs_delayed_ref_root *delayed_refs,
 282                      struct btrfs_delayed_ref_head *head,
 283                      struct btrfs_delayed_ref_node *ref, u64 seq)
 284 {
 285         struct rb_node *node;
 286         int mod = 0;
 287         int done = 0;
 288
 289         node = rb_next(&ref->rb_node);
 290         while (!done && node) {
 291                 struct btrfs_delayed_ref_node *next;
 292
 293                 next = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 294                 node = rb_next(node);
 295                 if (seq && next->seq >= seq)
 296                         break;
 297                 if (comp_entry(ref, next, 0))
 298                         continue;
 299
 300                 if (ref->action == next->action) {
 301                         mod = next->ref_mod;
 302                 } else {
 303                         if (ref->ref_mod < next->ref_mod) {
 304                                 struct btrfs_delayed_ref_node *tmp;
 305
 306                                 tmp = ref;
 307                                 ref = next;
 308                                 next = tmp;
 309                                 done = 1;
 310                         }
 311                         mod = -next->ref_mod;
 312                 }
 313
 314                 drop_delayed_ref(trans, delayed_refs, head, next);
 315                 ref->ref_mod += mod;
 316                 if (ref->ref_mod == 0) {
 317                         drop_delayed_ref(trans, delayed_refs, head, ref);
 318                         done = 1;
 319                 } else {
 320                         /*
 321                          * You can't have multiples of the same ref on a tree
 322                          * block.
 323                          */
 324                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 325                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 326                 }
 327         }
 328         return done;
 329 }
 330
 331 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 332                               struct btrfs_fs_info *fs_info,
 333                               struct btrfs_delayed_ref_root *delayed_refs,
 334                               struct btrfs_delayed_ref_head *head)
 335 {
 336         struct rb_node *node;
 337         u64 seq = 0;
 338
 339         assert_spin_locked(&head->lock);
 340         /*
 341          * We don't have too much refs to merge in the case of delayed data
 342          * refs.
 343          */
 344         if (head->is_data)
 345                 return;
 346
 347         spin_lock(&fs_info->tree_mod_seq_lock);
 348         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 349                 struct seq_list *elem;
 350
 351                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 352                                         struct seq_list, list);
 353                 seq = elem->seq;
 354         }
 355         spin_unlock(&fs_info->tree_mod_seq_lock);
 356
 357         node = rb_first(&head->ref_root);
 358         while (node) {
 359                 struct btrfs_delayed_ref_node *ref;
 360
 361                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
 362                                rb_node);
 363                 /* We can't merge refs that are outside of our seq count */
 364                 if (seq && ref->seq >= seq)
 365                         break;
 366                 if (merge_ref(trans, delayed_refs, head, ref, seq))
 367                         node = rb_first(&head->ref_root);
 368                 else
 369                         node = rb_next(&ref->rb_node);
 370         }
 371 }
 372
 373 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 374                             struct btrfs_delayed_ref_root *delayed_refs,
 375                             u64 seq)
 376 {
 377         struct seq_list *elem;
 378         int ret = 0;
 379
 380         spin_lock(&fs_info->tree_mod_seq_lock);
 381         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 382                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 383                                         struct seq_list, list);
 384                 if (seq >= elem->seq) {
 385                         pr_debug("holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)\n",
 386                                  (u32)(seq >> 32), (u32)seq,
 387                                  (u32)(elem->seq >> 32), (u32)elem->seq,
 388                                  delayed_refs);
 389                         ret = 1;
 390                 }
 391         }
 392
 393         spin_unlock(&fs_info->tree_mod_seq_lock);
 394         return ret;
 395 }
 396
 397 struct btrfs_delayed_ref_head *
 398 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 399 {
 400         struct btrfs_delayed_ref_root *delayed_refs;
 401         struct btrfs_delayed_ref_head *head;
 402         u64 start;
 403         bool loop = false;
 404
 405         delayed_refs = &trans->transaction->delayed_refs;
 406
 407 again:
 408         start = delayed_refs->run_delayed_start;
 409         head = find_ref_head(&delayed_refs->href_root, start, 1);
 410         if (!head && !loop) {
 411                 delayed_refs->run_delayed_start = 0;
 412                 start = 0;
 413                 loop = true;
 414                 head = find_ref_head(&delayed_refs->href_root, start, 1);
 415                 if (!head)
 416                         return NULL;
 417         } else if (!head && loop) {
 418                 return NULL;
 419         }
 420
 421         while (head->processing) {
 422                 struct rb_node *node;
 423
 424                 node = rb_next(&head->href_node);
 425                 if (!node) {
 426                         if (loop)
 427                                 return NULL;
 428                         delayed_refs->run_delayed_start = 0;
 429                         start = 0;
 430                         loop = true;
 431                         goto again;
 432                 }
 433                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 434                                 href_node);
 435         }
 436
 437         head->processing = 1;
 438         WARN_ON(delayed_refs->num_heads_ready == 0);
 439         delayed_refs->num_heads_ready--;
 440         delayed_refs->run_delayed_start = head->node.bytenr +
 441                 head->node.num_bytes;
 442         return head;
 443 }
 444
 445 /*
 446  * helper function to update an extent delayed ref in the
 447  * rbtree.  existing and update must both have the same
 448  * bytenr and parent
 449  *
 450  * This may free existing if the update cancels out whatever
 451  * operation it was doing.
 452  */
 453 static noinline void
 454 update_existing_ref(struct btrfs_trans_handle *trans,
 455                     struct btrfs_delayed_ref_root *delayed_refs,
 456                     struct btrfs_delayed_ref_head *head,
 457                     struct btrfs_delayed_ref_node *existing,
 458                     struct btrfs_delayed_ref_node *update)
 459 {
 460         if (update->action != existing->action) {
 461                 /*
 462                  * this is effectively undoing either an add or a
 463                  * drop.  We decrement the ref_mod, and if it goes
 464                  * down to zero we just delete the entry without
 465                  * every changing the extent allocation tree.
 466                  */
 467                 existing->ref_mod--;
 468                 if (existing->ref_mod == 0)
 469                         drop_delayed_ref(trans, delayed_refs, head, existing);
 470                 else
 471                         WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 472                                 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 473         } else {
 474                 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 475                         existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 476                 /*
 477                  * the action on the existing ref matches
 478                  * the action on the ref we're trying to add.
 479                  * Bump the ref_mod by one so the backref that
 480                  * is eventually added/removed has the correct
 481                  * reference count
 482                  */
 483                 existing->ref_mod += update->ref_mod;
 484         }
 485 }
 486
 487 /*
 488  * helper function to update the accounting in the head ref
 489  * existing and update must have the same bytenr
 490  */
 491 static noinline void
 492 update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
 493                          struct btrfs_delayed_ref_node *update)
 494 {
 495         struct btrfs_delayed_ref_head *existing_ref;
 496         struct btrfs_delayed_ref_head *ref;
 497
 498         existing_ref = btrfs_delayed_node_to_head(existing);
 499         ref = btrfs_delayed_node_to_head(update);
 500         BUG_ON(existing_ref->is_data != ref->is_data);
 501
 502         spin_lock(&existing_ref->lock);
 503         if (ref->must_insert_reserved) {
 504                 /* if the extent was freed and then
 505                  * reallocated before the delayed ref
 506                  * entries were processed, we can end up
 507                  * with an existing head ref without
 508                  * the must_insert_reserved flag set.
 509                  * Set it again here
 510                  */
 511                 existing_ref->must_insert_reserved = ref->must_insert_reserved;
 512
 513                 /*
 514                  * update the num_bytes so we make sure the accounting
 515                  * is done correctly
 516                  */
 517                 existing->num_bytes = update->num_bytes;
 518
 519         }
 520
 521         if (ref->extent_op) {
 522                 if (!existing_ref->extent_op) {
 523                         existing_ref->extent_op = ref->extent_op;
 524                 } else {
 525                         if (ref->extent_op->update_key) {
 526                                 memcpy(&existing_ref->extent_op->key,
 527                                        &ref->extent_op->key,
 528                                        sizeof(ref->extent_op->key));
 529                                 existing_ref->extent_op->update_key = 1;
 530                         }
 531                         if (ref->extent_op->update_flags) {
 532                                 existing_ref->extent_op->flags_to_set |=
 533                                         ref->extent_op->flags_to_set;
 534                                 existing_ref->extent_op->update_flags = 1;
 535                         }
 536                         btrfs_free_delayed_extent_op(ref->extent_op);
 537                 }
 538         }
 539         /*
 540          * update the reference mod on the head to reflect this new operation,
 541          * only need the lock for this case cause we could be processing it
 542          * currently, for refs we just added we know we're a-ok.
 543          */
 544         existing->ref_mod += update->ref_mod;
 545         spin_unlock(&existing_ref->lock);
 546 }
 547
 548 /*
 549  * helper function to actually insert a head node into the rbtree.
 550  * this does all the dirty work in terms of maintaining the correct
 551  * overall modification count.
 552  */
 553 static noinline struct btrfs_delayed_ref_head *
 554 add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 555                      struct btrfs_trans_handle *trans,
 556                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 557                      u64 num_bytes, int action, int is_data)
 558 {
 559         struct btrfs_delayed_ref_head *existing;
 560         struct btrfs_delayed_ref_head *head_ref = NULL;
 561         struct btrfs_delayed_ref_root *delayed_refs;
 562         int count_mod = 1;
 563         int must_insert_reserved = 0;
 564
 565         /*
 566          * the head node stores the sum of all the mods, so dropping a ref
 567          * should drop the sum in the head node by one.
 568          */
 569         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 570                 count_mod = 0;
 571         else if (action == BTRFS_DROP_DELAYED_REF)
 572                 count_mod = -1;
 573
 574         /*
 575          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 576          * the reserved accounting when the extent is finally added, or
 577          * if a later modification deletes the delayed ref without ever
 578          * inserting the extent into the extent allocation tree.
 579          * ref->must_insert_reserved is the flag used to record
 580          * that accounting mods are required.
 581          *
 582          * Once we record must_insert_reserved, switch the action to
 583          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 584          */
 585         if (action == BTRFS_ADD_DELAYED_EXTENT)
 586                 must_insert_reserved = 1;
 587         else
 588                 must_insert_reserved = 0;
 589
 590         delayed_refs = &trans->transaction->delayed_refs;
 591
 592         /* first set the basic ref node struct up */
 593         atomic_set(&ref->refs, 1);
 594         ref->bytenr = bytenr;
 595         ref->num_bytes = num_bytes;
 596         ref->ref_mod = count_mod;
 597         ref->type  = 0;
 598         ref->action  = 0;
 599         ref->is_head = 1;
 600         ref->in_tree = 1;
 601         ref->seq = 0;
 602
 603         head_ref = btrfs_delayed_node_to_head(ref);
 604         head_ref->must_insert_reserved = must_insert_reserved;
 605         head_ref->is_data = is_data;
 606         head_ref->ref_root = RB_ROOT;
 607         head_ref->processing = 0;
 608
 609         spin_lock_init(&head_ref->lock);
 610         mutex_init(&head_ref->mutex);
 611
 612         trace_add_delayed_ref_head(ref, head_ref, action);
 613
 614         existing = htree_insert(&delayed_refs->href_root,
 615                                 &head_ref->href_node);
 616         if (existing) {
 617                 update_existing_head_ref(&existing->node, ref);
 618                 /*
 619                  * we've updated the existing ref, free the newly
 620                  * allocated ref
 621                  */
 622                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 623                 head_ref = existing;
 624         } else {
 625                 delayed_refs->num_heads++;
 626                 delayed_refs->num_heads_ready++;
 627                 atomic_inc(&delayed_refs->num_entries);
 628                 trans->delayed_ref_updates++;
 629         }
 630         return head_ref;
 631 }
 632
 633 /*
 634  * helper to insert a delayed tree ref into the rbtree.
 635  */
 636 static noinline void
 637 add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 638                      struct btrfs_trans_handle *trans,
 639                      struct btrfs_delayed_ref_head *head_ref,
 640                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 641                      u64 num_bytes, u64 parent, u64 ref_root, int level,
 642                      int action, int no_quota)
 643 {
 644         struct btrfs_delayed_ref_node *existing;
 645         struct btrfs_delayed_tree_ref *full_ref;
 646         struct btrfs_delayed_ref_root *delayed_refs;
 647         u64 seq = 0;
 648
 649         if (action == BTRFS_ADD_DELAYED_EXTENT)
 650                 action = BTRFS_ADD_DELAYED_REF;
 651
 652         if (is_fstree(ref_root))
 653                 seq = atomic64_read(&fs_info->tree_mod_seq);
 654         delayed_refs = &trans->transaction->delayed_refs;
 655
 656         /* first set the basic ref node struct up */
 657         atomic_set(&ref->refs, 1);
 658         ref->bytenr = bytenr;
 659         ref->num_bytes = num_bytes;
 660         ref->ref_mod = 1;
 661         ref->action = action;
 662         ref->is_head = 0;
 663         ref->in_tree = 1;
 664         ref->no_quota = no_quota;
 665         ref->seq = seq;
 666
 667         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 668         full_ref->parent = parent;
 669         full_ref->root = ref_root;
 670         if (parent)
 671                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 672         else
 673                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 674         full_ref->level = level;
 675
 676         trace_add_delayed_tree_ref(ref, full_ref, action);
 677
 678         spin_lock(&head_ref->lock);
 679         existing = tree_insert(&head_ref->ref_root, &ref->rb_node);
 680         if (existing) {
 681                 update_existing_ref(trans, delayed_refs, head_ref, existing,
 682                                     ref);
 683                 /*
 684                  * we've updated the existing ref, free the newly
 685                  * allocated ref
 686                  */
 687                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 688         } else {
 689                 atomic_inc(&delayed_refs->num_entries);
 690                 trans->delayed_ref_updates++;
 691         }
 692         spin_unlock(&head_ref->lock);
 693 }
 694
 695 /*
 696  * helper to insert a delayed data ref into the rbtree.
 697  */
 698 static noinline void
 699 add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 700                      struct btrfs_trans_handle *trans,
 701                      struct btrfs_delayed_ref_head *head_ref,
 702                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 703                      u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
 704                      u64 offset, int action, int no_quota)
 705 {
 706         struct btrfs_delayed_ref_node *existing;
 707         struct btrfs_delayed_data_ref *full_ref;
 708         struct btrfs_delayed_ref_root *delayed_refs;
 709         u64 seq = 0;
 710
 711         if (action == BTRFS_ADD_DELAYED_EXTENT)
 712                 action = BTRFS_ADD_DELAYED_REF;
 713
 714         delayed_refs = &trans->transaction->delayed_refs;
 715
 716         if (is_fstree(ref_root))
 717                 seq = atomic64_read(&fs_info->tree_mod_seq);
 718
 719         /* first set the basic ref node struct up */
 720         atomic_set(&ref->refs, 1);
 721         ref->bytenr = bytenr;
 722         ref->num_bytes = num_bytes;
 723         ref->ref_mod = 1;
 724         ref->action = action;
 725         ref->is_head = 0;
 726         ref->in_tree = 1;
 727         ref->no_quota = no_quota;
 728         ref->seq = seq;
 729
 730         full_ref = btrfs_delayed_node_to_data_ref(ref);
 731         full_ref->parent = parent;
 732         full_ref->root = ref_root;
 733         if (parent)
 734                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 735         else
 736                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 737
 738         full_ref->objectid = owner;
 739         full_ref->offset = offset;
 740
 741         trace_add_delayed_data_ref(ref, full_ref, action);
 742
 743         spin_lock(&head_ref->lock);
 744         existing = tree_insert(&head_ref->ref_root, &ref->rb_node);
 745         if (existing) {
 746                 update_existing_ref(trans, delayed_refs, head_ref, existing,
 747                                     ref);
 748                 /*
 749                  * we've updated the existing ref, free the newly
 750                  * allocated ref
 751                  */
 752                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 753         } else {
 754                 atomic_inc(&delayed_refs->num_entries);
 755                 trans->delayed_ref_updates++;
 756         }
 757         spin_unlock(&head_ref->lock);
 758 }
 759
 760 /*
 761  * add a delayed tree ref.  This does all of the accounting required
 762  * to make sure the delayed ref is eventually processed before this
 763  * transaction commits.
 764  */
 765 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 766                                struct btrfs_trans_handle *trans,
 767                                u64 bytenr, u64 num_bytes, u64 parent,
 768                                u64 ref_root,  int level, int action,
 769                                struct btrfs_delayed_extent_op *extent_op,
 770                                int no_quota)
 771 {
 772         struct btrfs_delayed_tree_ref *ref;
 773         struct btrfs_delayed_ref_head *head_ref;
 774         struct btrfs_delayed_ref_root *delayed_refs;
 775
 776         if (!is_fstree(ref_root) || !fs_info->quota_enabled)
 777                 no_quota = 0;
 778
 779         BUG_ON(extent_op && extent_op->is_data);
 780         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 781         if (!ref)
 782                 return -ENOMEM;
 783
 784         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 785         if (!head_ref) {
 786                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 787                 return -ENOMEM;
 788         }
 789
 790         head_ref->extent_op = extent_op;
 791
 792         delayed_refs = &trans->transaction->delayed_refs;
 793         spin_lock(&delayed_refs->lock);
 794
 795         /*
 796          * insert both the head node and the new ref without dropping
 797          * the spin lock
 798          */
 799         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node,
 800                                         bytenr, num_bytes, action, 0);
 801
 802         add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 803                                    num_bytes, parent, ref_root, level, action,
 804                                    no_quota);
 805         spin_unlock(&delayed_refs->lock);
 806
 807         return 0;
 808 }
 809
 810 /*
 811  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 812  */
 813 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 814                                struct btrfs_trans_handle *trans,
 815                                u64 bytenr, u64 num_bytes,
 816                                u64 parent, u64 ref_root,
 817                                u64 owner, u64 offset, int action,
 818                                struct btrfs_delayed_extent_op *extent_op,
 819                                int no_quota)
 820 {
 821         struct btrfs_delayed_data_ref *ref;
 822         struct btrfs_delayed_ref_head *head_ref;
 823         struct btrfs_delayed_ref_root *delayed_refs;
 824
 825         if (!is_fstree(ref_root) || !fs_info->quota_enabled)
 826                 no_quota = 0;
 827
 828         BUG_ON(extent_op && !extent_op->is_data);
 829         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 830         if (!ref)
 831                 return -ENOMEM;
 832
 833         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 834         if (!head_ref) {
 835                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 836                 return -ENOMEM;
 837         }
 838
 839         head_ref->extent_op = extent_op;
 840
 841         delayed_refs = &trans->transaction->delayed_refs;
 842         spin_lock(&delayed_refs->lock);
 843
 844         /*
 845          * insert both the head node and the new ref without dropping
 846          * the spin lock
 847          */
 848         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node,
 849                                         bytenr, num_bytes, action, 1);
 850
 851         add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 852                                    num_bytes, parent, ref_root, owner, offset,
 853                                    action, no_quota);
 854         spin_unlock(&delayed_refs->lock);
 855
 856         return 0;
 857 }
 858
 859 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 860                                 struct btrfs_trans_handle *trans,
 861                                 u64 bytenr, u64 num_bytes,
 862                                 struct btrfs_delayed_extent_op *extent_op)
 863 {
 864         struct btrfs_delayed_ref_head *head_ref;
 865         struct btrfs_delayed_ref_root *delayed_refs;
 866
 867         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 868         if (!head_ref)
 869                 return -ENOMEM;
 870
 871         head_ref->extent_op = extent_op;
 872
 873         delayed_refs = &trans->transaction->delayed_refs;
 874         spin_lock(&delayed_refs->lock);
 875
 876         add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
 877                                    num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
 878                                    extent_op->is_data);
 879
 880         spin_unlock(&delayed_refs->lock);
 881         return 0;
 882 }
 883
 884 /*
 885  * this does a simple search for the head node for a given extent.
 886  * It must be called with the delayed ref spinlock held, and it returns
 887  * the head node if any where found, or NULL if not.
 888  */
 889 struct btrfs_delayed_ref_head *
 890 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
 891 {
 892         struct btrfs_delayed_ref_root *delayed_refs;
 893
 894         delayed_refs = &trans->transaction->delayed_refs;
 895         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
 896 }
 897
 898 void btrfs_delayed_ref_exit(void)
 899 {
 900         if (btrfs_delayed_ref_head_cachep)
 901                 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 902         if (btrfs_delayed_tree_ref_cachep)
 903                 kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 904         if (btrfs_delayed_data_ref_cachep)
 905                 kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 906         if (btrfs_delayed_extent_op_cachep)
 907                 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 908 }
 909
 910 int btrfs_delayed_ref_init(void)
 911 {
 912         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 913                                 "btrfs_delayed_ref_head",
 914                                 sizeof(struct btrfs_delayed_ref_head), 0,
 915                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 916         if (!btrfs_delayed_ref_head_cachep)
 917                 goto fail;
 918
 919         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 920                                 "btrfs_delayed_tree_ref",
 921                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 922                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 923         if (!btrfs_delayed_tree_ref_cachep)
 924                 goto fail;
 925
 926         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 927                                 "btrfs_delayed_data_ref",
 928                                 sizeof(struct btrfs_delayed_data_ref), 0,
 929                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 930         if (!btrfs_delayed_data_ref_cachep)
 931                 goto fail;
 932
 933         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 934                                 "btrfs_delayed_extent_op",
 935                                 sizeof(struct btrfs_delayed_extent_op), 0,
 936                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 937         if (!btrfs_delayed_extent_op_cachep)
 938                 goto fail;
 939
 940         return 0;
 941 fail:
 942         btrfs_delayed_ref_exit();
 943         return -ENOMEM;
 944 }