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         /* merging of sequenced refs is not allowed */
 110         if (compare_seq) {
 111                 if (ref1->seq < ref2->seq)
 112                         return -1;
 113                 if (ref1->seq > ref2->seq)
 114                         return 1;
 115         }
 116         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
 117             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
 118                 return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
 119                                       btrfs_delayed_node_to_tree_ref(ref1),
 120                                       ref1->type);
 121         } else if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY ||
 122                    ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
 123                 return comp_data_refs(btrfs_delayed_node_to_data_ref(ref2),
 124                                       btrfs_delayed_node_to_data_ref(ref1));
 125         }
 126         BUG();
 127         return 0;
 128 }
 129
 130 /*
 131  * insert a new ref into the rbtree.  This returns any existing refs
 132  * for the same (bytenr,parent) tuple, or NULL if the new node was properly
 133  * inserted.
 134  */
 135 static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
 136                                                   struct rb_node *node)
 137 {
 138         struct rb_node **p = &root->rb_node;
 139         struct rb_node *parent_node = NULL;
 140         struct btrfs_delayed_ref_node *entry;
 141         struct btrfs_delayed_ref_node *ins;
 142         int cmp;
 143
 144         ins = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 145         while (*p) {
 146                 parent_node = *p;
 147                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
 148                                  rb_node);
 149
 150                 cmp = comp_entry(entry, ins, 1);
 151                 if (cmp < 0)
 152                         p = &(*p)->rb_left;
 153                 else if (cmp > 0)
 154                         p = &(*p)->rb_right;
 155                 else
 156                         return entry;
 157         }
 158
 159         rb_link_node(node, parent_node, p);
 160         rb_insert_color(node, root);
 161         return NULL;
 162 }
 163
 164 /* insert a new ref to head ref rbtree */
 165 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
 166                                                    struct rb_node *node)
 167 {
 168         struct rb_node **p = &root->rb_node;
 169         struct rb_node *parent_node = NULL;
 170         struct btrfs_delayed_ref_head *entry;
 171         struct btrfs_delayed_ref_head *ins;
 172         u64 bytenr;
 173
 174         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
 175         bytenr = ins->node.bytenr;
 176         while (*p) {
 177                 parent_node = *p;
 178                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
 179                                  href_node);
 180
 181                 if (bytenr < entry->node.bytenr)
 182                         p = &(*p)->rb_left;
 183                 else if (bytenr > entry->node.bytenr)
 184                         p = &(*p)->rb_right;
 185                 else
 186                         return entry;
 187         }
 188
 189         rb_link_node(node, parent_node, p);
 190         rb_insert_color(node, root);
 191         return NULL;
 192 }
 193
 194 /*
 195  * find an head entry based on bytenr. This returns the delayed ref
 196  * head if it was able to find one, or NULL if nothing was in that spot.
 197  * If return_bigger is given, the next bigger entry is returned if no exact
 198  * match is found.
 199  */
 200 static struct btrfs_delayed_ref_head *
 201 find_ref_head(struct rb_root *root, u64 bytenr,
 202               struct btrfs_delayed_ref_head **last, int return_bigger)
 203 {
 204         struct rb_node *n;
 205         struct btrfs_delayed_ref_head *entry;
 206         int cmp = 0;
 207
 208         n = root->rb_node;
 209         entry = NULL;
 210         while (n) {
 211                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
 212                 if (last)
 213                         *last = entry;
 214
 215                 if (bytenr < entry->node.bytenr)
 216                         cmp = -1;
 217                 else if (bytenr > entry->node.bytenr)
 218                         cmp = 1;
 219                 else
 220                         cmp = 0;
 221
 222                 if (cmp < 0)
 223                         n = n->rb_left;
 224                 else if (cmp > 0)
 225                         n = n->rb_right;
 226                 else
 227                         return entry;
 228         }
 229         if (entry && return_bigger) {
 230                 if (cmp > 0) {
 231                         n = rb_next(&entry->href_node);
 232                         if (!n)
 233                                 n = rb_first(root);
 234                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
 235                                          href_node);
 236                         if (last)
 237                                 *last = entry;
 238                         return entry;
 239                 }
 240                 return entry;
 241         }
 242         return NULL;
 243 }
 244
 245 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 246                            struct btrfs_delayed_ref_head *head)
 247 {
 248         struct btrfs_delayed_ref_root *delayed_refs;
 249
 250         delayed_refs = &trans->transaction->delayed_refs;
 251         assert_spin_locked(&delayed_refs->lock);
 252         if (mutex_trylock(&head->mutex))
 253                 return 0;
 254
 255         atomic_inc(&head->node.refs);
 256         spin_unlock(&delayed_refs->lock);
 257
 258         mutex_lock(&head->mutex);
 259         spin_lock(&delayed_refs->lock);
 260         if (!head->node.in_tree) {
 261                 mutex_unlock(&head->mutex);
 262                 btrfs_put_delayed_ref(&head->node);
 263                 return -EAGAIN;
 264         }
 265         btrfs_put_delayed_ref(&head->node);
 266         return 0;
 267 }
 268
 269 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 270                                     struct btrfs_delayed_ref_root *delayed_refs,
 271                                     struct btrfs_delayed_ref_head *head,
 272                                     struct btrfs_delayed_ref_node *ref)
 273 {
 274         if (btrfs_delayed_ref_is_head(ref)) {
 275                 head = btrfs_delayed_node_to_head(ref);
 276                 rb_erase(&head->href_node, &delayed_refs->href_root);
 277         } else {
 278                 assert_spin_locked(&head->lock);
 279                 rb_erase(&ref->rb_node, &head->ref_root);
 280         }
 281         ref->in_tree = 0;
 282         btrfs_put_delayed_ref(ref);
 283         atomic_dec(&delayed_refs->num_entries);
 284         if (trans->delayed_ref_updates)
 285                 trans->delayed_ref_updates--;
 286 }
 287
 288 static int merge_ref(struct btrfs_trans_handle *trans,
 289                      struct btrfs_delayed_ref_root *delayed_refs,
 290                      struct btrfs_delayed_ref_head *head,
 291                      struct btrfs_delayed_ref_node *ref, u64 seq)
 292 {
 293         struct rb_node *node;
 294         int mod = 0;
 295         int done = 0;
 296
 297         node = rb_next(&ref->rb_node);
 298         while (!done && node) {
 299                 struct btrfs_delayed_ref_node *next;
 300
 301                 next = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 302                 node = rb_next(node);
 303                 if (seq && next->seq >= seq)
 304                         break;
 305                 if (comp_entry(ref, next, 0))
 306                         continue;
 307
 308                 if (ref->action == next->action) {
 309                         mod = next->ref_mod;
 310                 } else {
 311                         if (ref->ref_mod < next->ref_mod) {
 312                                 struct btrfs_delayed_ref_node *tmp;
 313
 314                                 tmp = ref;
 315                                 ref = next;
 316                                 next = tmp;
 317                                 done = 1;
 318                         }
 319                         mod = -next->ref_mod;
 320                 }
 321
 322                 drop_delayed_ref(trans, delayed_refs, head, next);
 323                 ref->ref_mod += mod;
 324                 if (ref->ref_mod == 0) {
 325                         drop_delayed_ref(trans, delayed_refs, head, ref);
 326                         done = 1;
 327                 } else {
 328                         /*
 329                          * You can't have multiples of the same ref on a tree
 330                          * block.
 331                          */
 332                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 333                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 334                 }
 335         }
 336         return done;
 337 }
 338
 339 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 340                               struct btrfs_fs_info *fs_info,
 341                               struct btrfs_delayed_ref_root *delayed_refs,
 342                               struct btrfs_delayed_ref_head *head)
 343 {
 344         struct rb_node *node;
 345         u64 seq = 0;
 346
 347         assert_spin_locked(&head->lock);
 348         /*
 349          * We don't have too much refs to merge in the case of delayed data
 350          * refs.
 351          */
 352         if (head->is_data)
 353                 return;
 354
 355         spin_lock(&fs_info->tree_mod_seq_lock);
 356         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 357                 struct seq_list *elem;
 358
 359                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 360                                         struct seq_list, list);
 361                 seq = elem->seq;
 362         }
 363         spin_unlock(&fs_info->tree_mod_seq_lock);
 364
 365         node = rb_first(&head->ref_root);
 366         while (node) {
 367                 struct btrfs_delayed_ref_node *ref;
 368
 369                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
 370                                rb_node);
 371                 /* We can't merge refs that are outside of our seq count */
 372                 if (seq && ref->seq >= seq)
 373                         break;
 374                 if (merge_ref(trans, delayed_refs, head, ref, seq))
 375                         node = rb_first(&head->ref_root);
 376                 else
 377                         node = rb_next(&ref->rb_node);
 378         }
 379 }
 380
 381 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 382                             struct btrfs_delayed_ref_root *delayed_refs,
 383                             u64 seq)
 384 {
 385         struct seq_list *elem;
 386         int ret = 0;
 387
 388         spin_lock(&fs_info->tree_mod_seq_lock);
 389         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 390                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 391                                         struct seq_list, list);
 392                 if (seq >= elem->seq) {
 393                         pr_debug("holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)\n",
 394                                  (u32)(seq >> 32), (u32)seq,
 395                                  (u32)(elem->seq >> 32), (u32)elem->seq,
 396                                  delayed_refs);
 397                         ret = 1;
 398                 }
 399         }
 400
 401         spin_unlock(&fs_info->tree_mod_seq_lock);
 402         return ret;
 403 }
 404
 405 struct btrfs_delayed_ref_head *
 406 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 407 {
 408         struct btrfs_delayed_ref_root *delayed_refs;
 409         struct btrfs_delayed_ref_head *head;
 410         u64 start;
 411         bool loop = false;
 412
 413         delayed_refs = &trans->transaction->delayed_refs;
 414
 415 again:
 416         start = delayed_refs->run_delayed_start;
 417         head = find_ref_head(&delayed_refs->href_root, start, NULL, 1);
 418         if (!head && !loop) {
 419                 delayed_refs->run_delayed_start = 0;
 420                 start = 0;
 421                 loop = true;
 422                 head = find_ref_head(&delayed_refs->href_root, start, NULL, 1);
 423                 if (!head)
 424                         return NULL;
 425         } else if (!head && loop) {
 426                 return NULL;
 427         }
 428
 429         while (head->processing) {
 430                 struct rb_node *node;
 431
 432                 node = rb_next(&head->href_node);
 433                 if (!node) {
 434                         if (loop)
 435                                 return NULL;
 436                         delayed_refs->run_delayed_start = 0;
 437                         start = 0;
 438                         loop = true;
 439                         goto again;
 440                 }
 441                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 442                                 href_node);
 443         }
 444
 445         head->processing = 1;
 446         WARN_ON(delayed_refs->num_heads_ready == 0);
 447         delayed_refs->num_heads_ready--;
 448         delayed_refs->run_delayed_start = head->node.bytenr +
 449                 head->node.num_bytes;
 450         return head;
 451 }
 452
 453 /*
 454  * helper function to update an extent delayed ref in the
 455  * rbtree.  existing and update must both have the same
 456  * bytenr and parent
 457  *
 458  * This may free existing if the update cancels out whatever
 459  * operation it was doing.
 460  */
 461 static noinline void
 462 update_existing_ref(struct btrfs_trans_handle *trans,
 463                     struct btrfs_delayed_ref_root *delayed_refs,
 464                     struct btrfs_delayed_ref_head *head,
 465                     struct btrfs_delayed_ref_node *existing,
 466                     struct btrfs_delayed_ref_node *update)
 467 {
 468         if (update->action != existing->action) {
 469                 /*
 470                  * this is effectively undoing either an add or a
 471                  * drop.  We decrement the ref_mod, and if it goes
 472                  * down to zero we just delete the entry without
 473                  * every changing the extent allocation tree.
 474                  */
 475                 existing->ref_mod--;
 476                 if (existing->ref_mod == 0)
 477                         drop_delayed_ref(trans, delayed_refs, head, existing);
 478                 else
 479                         WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 480                                 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 481         } else {
 482                 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 483                         existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 484                 /*
 485                  * the action on the existing ref matches
 486                  * the action on the ref we're trying to add.
 487                  * Bump the ref_mod by one so the backref that
 488                  * is eventually added/removed has the correct
 489                  * reference count
 490                  */
 491                 existing->ref_mod += update->ref_mod;
 492         }
 493 }
 494
 495 /*
 496  * helper function to update the accounting in the head ref
 497  * existing and update must have the same bytenr
 498  */
 499 static noinline void
 500 update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
 501                          struct btrfs_delayed_ref_node *update)
 502 {
 503         struct btrfs_delayed_ref_head *existing_ref;
 504         struct btrfs_delayed_ref_head *ref;
 505
 506         existing_ref = btrfs_delayed_node_to_head(existing);
 507         ref = btrfs_delayed_node_to_head(update);
 508         BUG_ON(existing_ref->is_data != ref->is_data);
 509
 510         if (ref->must_insert_reserved) {
 511                 /* if the extent was freed and then
 512                  * reallocated before the delayed ref
 513                  * entries were processed, we can end up
 514                  * with an existing head ref without
 515                  * the must_insert_reserved flag set.
 516                  * Set it again here
 517                  */
 518                 existing_ref->must_insert_reserved = ref->must_insert_reserved;
 519
 520                 /*
 521                  * update the num_bytes so we make sure the accounting
 522                  * is done correctly
 523                  */
 524                 existing->num_bytes = update->num_bytes;
 525
 526         }
 527
 528         if (ref->extent_op) {
 529                 if (!existing_ref->extent_op) {
 530                         existing_ref->extent_op = ref->extent_op;
 531                 } else {
 532                         if (ref->extent_op->update_key) {
 533                                 memcpy(&existing_ref->extent_op->key,
 534                                        &ref->extent_op->key,
 535                                        sizeof(ref->extent_op->key));
 536                                 existing_ref->extent_op->update_key = 1;
 537                         }
 538                         if (ref->extent_op->update_flags) {
 539                                 existing_ref->extent_op->flags_to_set |=
 540                                         ref->extent_op->flags_to_set;
 541                                 existing_ref->extent_op->update_flags = 1;
 542                         }
 543                         btrfs_free_delayed_extent_op(ref->extent_op);
 544                 }
 545         }
 546         /*
 547          * update the reference mod on the head to reflect this new operation,
 548          * only need the lock for this case cause we could be processing it
 549          * currently, for refs we just added we know we're a-ok.
 550          */
 551         spin_lock(&existing_ref->lock);
 552         existing->ref_mod += update->ref_mod;
 553         spin_unlock(&existing_ref->lock);
 554 }
 555
 556 /*
 557  * helper function to actually insert a head node into the rbtree.
 558  * this does all the dirty work in terms of maintaining the correct
 559  * overall modification count.
 560  */
 561 static noinline struct btrfs_delayed_ref_head *
 562 add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 563                      struct btrfs_trans_handle *trans,
 564                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 565                      u64 num_bytes, int action, int is_data)
 566 {
 567         struct btrfs_delayed_ref_head *existing;
 568         struct btrfs_delayed_ref_head *head_ref = NULL;
 569         struct btrfs_delayed_ref_root *delayed_refs;
 570         int count_mod = 1;
 571         int must_insert_reserved = 0;
 572
 573         /*
 574          * the head node stores the sum of all the mods, so dropping a ref
 575          * should drop the sum in the head node by one.
 576          */
 577         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 578                 count_mod = 0;
 579         else if (action == BTRFS_DROP_DELAYED_REF)
 580                 count_mod = -1;
 581
 582         /*
 583          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 584          * the reserved accounting when the extent is finally added, or
 585          * if a later modification deletes the delayed ref without ever
 586          * inserting the extent into the extent allocation tree.
 587          * ref->must_insert_reserved is the flag used to record
 588          * that accounting mods are required.
 589          *
 590          * Once we record must_insert_reserved, switch the action to
 591          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 592          */
 593         if (action == BTRFS_ADD_DELAYED_EXTENT)
 594                 must_insert_reserved = 1;
 595         else
 596                 must_insert_reserved = 0;
 597
 598         delayed_refs = &trans->transaction->delayed_refs;
 599
 600         /* first set the basic ref node struct up */
 601         atomic_set(&ref->refs, 1);
 602         ref->bytenr = bytenr;
 603         ref->num_bytes = num_bytes;
 604         ref->ref_mod = count_mod;
 605         ref->type  = 0;
 606         ref->action  = 0;
 607         ref->is_head = 1;
 608         ref->in_tree = 1;
 609         ref->seq = 0;
 610
 611         head_ref = btrfs_delayed_node_to_head(ref);
 612         head_ref->must_insert_reserved = must_insert_reserved;
 613         head_ref->is_data = is_data;
 614         head_ref->ref_root = RB_ROOT;
 615         head_ref->processing = 0;
 616
 617         spin_lock_init(&head_ref->lock);
 618         mutex_init(&head_ref->mutex);
 619
 620         trace_add_delayed_ref_head(ref, head_ref, action);
 621
 622         existing = htree_insert(&delayed_refs->href_root,
 623                                 &head_ref->href_node);
 624         if (existing) {
 625                 update_existing_head_ref(&existing->node, ref);
 626                 /*
 627                  * we've updated the existing ref, free the newly
 628                  * allocated ref
 629                  */
 630                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 631                 head_ref = existing;
 632         } else {
 633                 delayed_refs->num_heads++;
 634                 delayed_refs->num_heads_ready++;
 635                 atomic_inc(&delayed_refs->num_entries);
 636                 trans->delayed_ref_updates++;
 637         }
 638         return head_ref;
 639 }
 640
 641 /*
 642  * helper to insert a delayed tree ref into the rbtree.
 643  */
 644 static noinline void
 645 add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 646                      struct btrfs_trans_handle *trans,
 647                      struct btrfs_delayed_ref_head *head_ref,
 648                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 649                      u64 num_bytes, u64 parent, u64 ref_root, int level,
 650                      int action, int for_cow)
 651 {
 652         struct btrfs_delayed_ref_node *existing;
 653         struct btrfs_delayed_tree_ref *full_ref;
 654         struct btrfs_delayed_ref_root *delayed_refs;
 655         u64 seq = 0;
 656
 657         if (action == BTRFS_ADD_DELAYED_EXTENT)
 658                 action = BTRFS_ADD_DELAYED_REF;
 659
 660         delayed_refs = &trans->transaction->delayed_refs;
 661
 662         /* first set the basic ref node struct up */
 663         atomic_set(&ref->refs, 1);
 664         ref->bytenr = bytenr;
 665         ref->num_bytes = num_bytes;
 666         ref->ref_mod = 1;
 667         ref->action = action;
 668         ref->is_head = 0;
 669         ref->in_tree = 1;
 670
 671         if (need_ref_seq(for_cow, ref_root))
 672                 seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
 673         ref->seq = seq;
 674
 675         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 676         full_ref->parent = parent;
 677         full_ref->root = ref_root;
 678         if (parent)
 679                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 680         else
 681                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 682         full_ref->level = level;
 683
 684         trace_add_delayed_tree_ref(ref, full_ref, action);
 685
 686         spin_lock(&head_ref->lock);
 687         existing = tree_insert(&head_ref->ref_root, &ref->rb_node);
 688         if (existing) {
 689                 update_existing_ref(trans, delayed_refs, head_ref, existing,
 690                                     ref);
 691                 /*
 692                  * we've updated the existing ref, free the newly
 693                  * allocated ref
 694                  */
 695                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 696         } else {
 697                 atomic_inc(&delayed_refs->num_entries);
 698                 trans->delayed_ref_updates++;
 699         }
 700         spin_unlock(&head_ref->lock);
 701 }
 702
 703 /*
 704  * helper to insert a delayed data ref into the rbtree.
 705  */
 706 static noinline void
 707 add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 708                      struct btrfs_trans_handle *trans,
 709                      struct btrfs_delayed_ref_head *head_ref,
 710                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 711                      u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
 712                      u64 offset, int action, int for_cow)
 713 {
 714         struct btrfs_delayed_ref_node *existing;
 715         struct btrfs_delayed_data_ref *full_ref;
 716         struct btrfs_delayed_ref_root *delayed_refs;
 717         u64 seq = 0;
 718
 719         if (action == BTRFS_ADD_DELAYED_EXTENT)
 720                 action = BTRFS_ADD_DELAYED_REF;
 721
 722         delayed_refs = &trans->transaction->delayed_refs;
 723
 724         /* first set the basic ref node struct up */
 725         atomic_set(&ref->refs, 1);
 726         ref->bytenr = bytenr;
 727         ref->num_bytes = num_bytes;
 728         ref->ref_mod = 1;
 729         ref->action = action;
 730         ref->is_head = 0;
 731         ref->in_tree = 1;
 732
 733         if (need_ref_seq(for_cow, ref_root))
 734                 seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
 735         ref->seq = seq;
 736
 737         full_ref = btrfs_delayed_node_to_data_ref(ref);
 738         full_ref->parent = parent;
 739         full_ref->root = ref_root;
 740         if (parent)
 741                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 742         else
 743                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 744
 745         full_ref->objectid = owner;
 746         full_ref->offset = offset;
 747
 748         trace_add_delayed_data_ref(ref, full_ref, action);
 749
 750         spin_lock(&head_ref->lock);
 751         existing = tree_insert(&head_ref->ref_root, &ref->rb_node);
 752         if (existing) {
 753                 update_existing_ref(trans, delayed_refs, head_ref, existing,
 754                                     ref);
 755                 /*
 756                  * we've updated the existing ref, free the newly
 757                  * allocated ref
 758                  */
 759                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 760         } else {
 761                 atomic_inc(&delayed_refs->num_entries);
 762                 trans->delayed_ref_updates++;
 763         }
 764         spin_unlock(&head_ref->lock);
 765 }
 766
 767 /*
 768  * add a delayed tree ref.  This does all of the accounting required
 769  * to make sure the delayed ref is eventually processed before this
 770  * transaction commits.
 771  */
 772 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 773                                struct btrfs_trans_handle *trans,
 774                                u64 bytenr, u64 num_bytes, u64 parent,
 775                                u64 ref_root,  int level, int action,
 776                                struct btrfs_delayed_extent_op *extent_op,
 777                                int for_cow)
 778 {
 779         struct btrfs_delayed_tree_ref *ref;
 780         struct btrfs_delayed_ref_head *head_ref;
 781         struct btrfs_delayed_ref_root *delayed_refs;
 782
 783         BUG_ON(extent_op && extent_op->is_data);
 784         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 785         if (!ref)
 786                 return -ENOMEM;
 787
 788         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 789         if (!head_ref) {
 790                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 791                 return -ENOMEM;
 792         }
 793
 794         head_ref->extent_op = extent_op;
 795
 796         delayed_refs = &trans->transaction->delayed_refs;
 797         spin_lock(&delayed_refs->lock);
 798
 799         /*
 800          * insert both the head node and the new ref without dropping
 801          * the spin lock
 802          */
 803         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node,
 804                                         bytenr, num_bytes, action, 0);
 805
 806         add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 807                                    num_bytes, parent, ref_root, level, action,
 808                                    for_cow);
 809         spin_unlock(&delayed_refs->lock);
 810         if (need_ref_seq(for_cow, ref_root))
 811                 btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
 812
 813         return 0;
 814 }
 815
 816 /*
 817  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 818  */
 819 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 820                                struct btrfs_trans_handle *trans,
 821                                u64 bytenr, u64 num_bytes,
 822                                u64 parent, u64 ref_root,
 823                                u64 owner, u64 offset, int action,
 824                                struct btrfs_delayed_extent_op *extent_op,
 825                                int for_cow)
 826 {
 827         struct btrfs_delayed_data_ref *ref;
 828         struct btrfs_delayed_ref_head *head_ref;
 829         struct btrfs_delayed_ref_root *delayed_refs;
 830
 831         BUG_ON(extent_op && !extent_op->is_data);
 832         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 833         if (!ref)
 834                 return -ENOMEM;
 835
 836         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 837         if (!head_ref) {
 838                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 839                 return -ENOMEM;
 840         }
 841
 842         head_ref->extent_op = extent_op;
 843
 844         delayed_refs = &trans->transaction->delayed_refs;
 845         spin_lock(&delayed_refs->lock);
 846
 847         /*
 848          * insert both the head node and the new ref without dropping
 849          * the spin lock
 850          */
 851         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node,
 852                                         bytenr, num_bytes, action, 1);
 853
 854         add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 855                                    num_bytes, parent, ref_root, owner, offset,
 856                                    action, for_cow);
 857         spin_unlock(&delayed_refs->lock);
 858         if (need_ref_seq(for_cow, ref_root))
 859                 btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
 860
 861         return 0;
 862 }
 863
 864 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 865                                 struct btrfs_trans_handle *trans,
 866                                 u64 bytenr, u64 num_bytes,
 867                                 struct btrfs_delayed_extent_op *extent_op)
 868 {
 869         struct btrfs_delayed_ref_head *head_ref;
 870         struct btrfs_delayed_ref_root *delayed_refs;
 871
 872         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 873         if (!head_ref)
 874                 return -ENOMEM;
 875
 876         head_ref->extent_op = extent_op;
 877
 878         delayed_refs = &trans->transaction->delayed_refs;
 879         spin_lock(&delayed_refs->lock);
 880
 881         add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
 882                                    num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
 883                                    extent_op->is_data);
 884
 885         spin_unlock(&delayed_refs->lock);
 886         return 0;
 887 }
 888
 889 /*
 890  * this does a simple search for the head node for a given extent.
 891  * It must be called with the delayed ref spinlock held, and it returns
 892  * the head node if any where found, or NULL if not.
 893  */
 894 struct btrfs_delayed_ref_head *
 895 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
 896 {
 897         struct btrfs_delayed_ref_root *delayed_refs;
 898
 899         delayed_refs = &trans->transaction->delayed_refs;
 900         return find_ref_head(&delayed_refs->href_root, bytenr, NULL, 0);
 901 }
 902
 903 void btrfs_delayed_ref_exit(void)
 904 {
 905         if (btrfs_delayed_ref_head_cachep)
 906                 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 907         if (btrfs_delayed_tree_ref_cachep)
 908                 kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 909         if (btrfs_delayed_data_ref_cachep)
 910                 kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 911         if (btrfs_delayed_extent_op_cachep)
 912                 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 913 }
 914
 915 int btrfs_delayed_ref_init(void)
 916 {
 917         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 918                                 "btrfs_delayed_ref_head",
 919                                 sizeof(struct btrfs_delayed_ref_head), 0,
 920                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 921         if (!btrfs_delayed_ref_head_cachep)
 922                 goto fail;
 923
 924         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 925                                 "btrfs_delayed_tree_ref",
 926                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 927                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 928         if (!btrfs_delayed_tree_ref_cachep)
 929                 goto fail;
 930
 931         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 932                                 "btrfs_delayed_data_ref",
 933                                 sizeof(struct btrfs_delayed_data_ref), 0,
 934                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 935         if (!btrfs_delayed_data_ref_cachep)
 936                 goto fail;
 937
 938         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 939                                 "btrfs_delayed_extent_op",
 940                                 sizeof(struct btrfs_delayed_extent_op), 0,
 941                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 942         if (!btrfs_delayed_extent_op_cachep)
 943                 goto fail;
 944
 945         return 0;
 946 fail:
 947         btrfs_delayed_ref_exit();
 948         return -ENOMEM;
 949 }