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 /*
  27  * delayed back reference update tracking.  For subvolume trees
  28  * we queue up extent allocations and backref maintenance for
  29  * delayed processing.   This avoids deep call chains where we
  30  * add extents in the middle of btrfs_search_slot, and it allows
  31  * us to buffer up frequently modified backrefs in an rb tree instead
  32  * of hammering updates on the extent allocation tree.
  33  */
  34
  35 /*
  36  * compare two delayed tree backrefs with same bytenr and type
  37  */
  38 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
  39                           struct btrfs_delayed_tree_ref *ref1)
  40 {
  41         if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
  42                 if (ref1->root < ref2->root)
  43                         return -1;
  44                 if (ref1->root > ref2->root)
  45                         return 1;
  46         } else {
  47                 if (ref1->parent < ref2->parent)
  48                         return -1;
  49                 if (ref1->parent > ref2->parent)
  50                         return 1;
  51         }
  52         return 0;
  53 }
  54
  55 /*
  56  * compare two delayed data backrefs with same bytenr and type
  57  */
  58 static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
  59                           struct btrfs_delayed_data_ref *ref1)
  60 {
  61         if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
  62                 if (ref1->root < ref2->root)
  63                         return -1;
  64                 if (ref1->root > ref2->root)
  65                         return 1;
  66                 if (ref1->objectid < ref2->objectid)
  67                         return -1;
  68                 if (ref1->objectid > ref2->objectid)
  69                         return 1;
  70                 if (ref1->offset < ref2->offset)
  71                         return -1;
  72                 if (ref1->offset > ref2->offset)
  73                         return 1;
  74         } else {
  75                 if (ref1->parent < ref2->parent)
  76                         return -1;
  77                 if (ref1->parent > ref2->parent)
  78                         return 1;
  79         }
  80         return 0;
  81 }
  82
  83 /*
  84  * entries in the rb tree are ordered by the byte number of the extent,
  85  * type of the delayed backrefs and content of delayed backrefs.
  86  */
  87 static int comp_entry(struct btrfs_delayed_ref_node *ref2,
  88                       struct btrfs_delayed_ref_node *ref1)
  89 {
  90         if (ref1->bytenr < ref2->bytenr)
  91                 return -1;
  92         if (ref1->bytenr > ref2->bytenr)
  93                 return 1;
  94         if (ref1->is_head && ref2->is_head)
  95                 return 0;
  96         if (ref2->is_head)
  97                 return -1;
  98         if (ref1->is_head)
  99                 return 1;
 100         if (ref1->type < ref2->type)
 101                 return -1;
 102         if (ref1->type > ref2->type)
 103                 return 1;
 104         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
 105             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
 106                 return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
 107                                       btrfs_delayed_node_to_tree_ref(ref1));
 108         } else if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY ||
 109                    ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
 110                 return comp_data_refs(btrfs_delayed_node_to_data_ref(ref2),
 111                                       btrfs_delayed_node_to_data_ref(ref1));
 112         }
 113         BUG();
 114         return 0;
 115 }
 116
 117 /*
 118  * insert a new ref into the rbtree.  This returns any existing refs
 119  * for the same (bytenr,parent) tuple, or NULL if the new node was properly
 120  * inserted.
 121  */
 122 static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
 123                                                   struct rb_node *node)
 124 {
 125         struct rb_node **p = &root->rb_node;
 126         struct rb_node *parent_node = NULL;
 127         struct btrfs_delayed_ref_node *entry;
 128         struct btrfs_delayed_ref_node *ins;
 129         int cmp;
 130
 131         ins = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 132         while (*p) {
 133                 parent_node = *p;
 134                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
 135                                  rb_node);
 136
 137                 cmp = comp_entry(entry, ins);
 138                 if (cmp < 0)
 139                         p = &(*p)->rb_left;
 140                 else if (cmp > 0)
 141                         p = &(*p)->rb_right;
 142                 else
 143                         return entry;
 144         }
 145
 146         rb_link_node(node, parent_node, p);
 147         rb_insert_color(node, root);
 148         return NULL;
 149 }
 150
 151 /*
 152  * find an head entry based on bytenr. This returns the delayed ref
 153  * head if it was able to find one, or NULL if nothing was in that spot
 154  */
 155 static struct btrfs_delayed_ref_node *find_ref_head(struct rb_root *root,
 156                                   u64 bytenr,
 157                                   struct btrfs_delayed_ref_node **last)
 158 {
 159         struct rb_node *n = root->rb_node;
 160         struct btrfs_delayed_ref_node *entry;
 161         int cmp;
 162
 163         while (n) {
 164                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
 165                 WARN_ON(!entry->in_tree);
 166                 if (last)
 167                         *last = entry;
 168
 169                 if (bytenr < entry->bytenr)
 170                         cmp = -1;
 171                 else if (bytenr > entry->bytenr)
 172                         cmp = 1;
 173                 else if (!btrfs_delayed_ref_is_head(entry))
 174                         cmp = 1;
 175                 else
 176                         cmp = 0;
 177
 178                 if (cmp < 0)
 179                         n = n->rb_left;
 180                 else if (cmp > 0)
 181                         n = n->rb_right;
 182                 else
 183                         return entry;
 184         }
 185         return NULL;
 186 }
 187
 188 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 189                            struct btrfs_delayed_ref_head *head)
 190 {
 191         struct btrfs_delayed_ref_root *delayed_refs;
 192
 193         delayed_refs = &trans->transaction->delayed_refs;
 194         assert_spin_locked(&delayed_refs->lock);
 195         if (mutex_trylock(&head->mutex))
 196                 return 0;
 197
 198         atomic_inc(&head->node.refs);
 199         spin_unlock(&delayed_refs->lock);
 200
 201         mutex_lock(&head->mutex);
 202         spin_lock(&delayed_refs->lock);
 203         if (!head->node.in_tree) {
 204                 mutex_unlock(&head->mutex);
 205                 btrfs_put_delayed_ref(&head->node);
 206                 return -EAGAIN;
 207         }
 208         btrfs_put_delayed_ref(&head->node);
 209         return 0;
 210 }
 211
 212 int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
 213                            struct list_head *cluster, u64 start)
 214 {
 215         int count = 0;
 216         struct btrfs_delayed_ref_root *delayed_refs;
 217         struct rb_node *node;
 218         struct btrfs_delayed_ref_node *ref;
 219         struct btrfs_delayed_ref_head *head;
 220
 221         delayed_refs = &trans->transaction->delayed_refs;
 222         if (start == 0) {
 223                 node = rb_first(&delayed_refs->root);
 224         } else {
 225                 ref = NULL;
 226                 find_ref_head(&delayed_refs->root, start, &ref);
 227                 if (ref) {
 228                         struct btrfs_delayed_ref_node *tmp;
 229
 230                         node = rb_prev(&ref->rb_node);
 231                         while (node) {
 232                                 tmp = rb_entry(node,
 233                                                struct btrfs_delayed_ref_node,
 234                                                rb_node);
 235                                 if (tmp->bytenr < start)
 236                                         break;
 237                                 ref = tmp;
 238                                 node = rb_prev(&ref->rb_node);
 239                         }
 240                         node = &ref->rb_node;
 241                 } else
 242                         node = rb_first(&delayed_refs->root);
 243         }
 244 again:
 245         while (node && count < 32) {
 246                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 247                 if (btrfs_delayed_ref_is_head(ref)) {
 248                         head = btrfs_delayed_node_to_head(ref);
 249                         if (list_empty(&head->cluster)) {
 250                                 list_add_tail(&head->cluster, cluster);
 251                                 delayed_refs->run_delayed_start =
 252                                         head->node.bytenr;
 253                                 count++;
 254
 255                                 WARN_ON(delayed_refs->num_heads_ready == 0);
 256                                 delayed_refs->num_heads_ready--;
 257                         } else if (count) {
 258                                 /* the goal of the clustering is to find extents
 259                                  * that are likely to end up in the same extent
 260                                  * leaf on disk.  So, we don't want them spread
 261                                  * all over the tree.  Stop now if we've hit
 262                                  * a head that was already in use
 263                                  */
 264                                 break;
 265                         }
 266                 }
 267                 node = rb_next(node);
 268         }
 269         if (count) {
 270                 return 0;
 271         } else if (start) {
 272                 /*
 273                  * we've gone to the end of the rbtree without finding any
 274                  * clusters.  start from the beginning and try again
 275                  */
 276                 start = 0;
 277                 node = rb_first(&delayed_refs->root);
 278                 goto again;
 279         }
 280         return 1;
 281 }
 282
 283 /*
 284  * This checks to see if there are any delayed refs in the
 285  * btree for a given bytenr.  It returns one if it finds any
 286  * and zero otherwise.
 287  *
 288  * If it only finds a head node, it returns 0.
 289  *
 290  * The idea is to use this when deciding if you can safely delete an
 291  * extent from the extent allocation tree.  There may be a pending
 292  * ref in the rbtree that adds or removes references, so as long as this
 293  * returns one you need to leave the BTRFS_EXTENT_ITEM in the extent
 294  * allocation tree.
 295  */
 296 int btrfs_delayed_ref_pending(struct btrfs_trans_handle *trans, u64 bytenr)
 297 {
 298         struct btrfs_delayed_ref_node *ref;
 299         struct btrfs_delayed_ref_root *delayed_refs;
 300         struct rb_node *prev_node;
 301         int ret = 0;
 302
 303         delayed_refs = &trans->transaction->delayed_refs;
 304         spin_lock(&delayed_refs->lock);
 305
 306         ref = find_ref_head(&delayed_refs->root, bytenr, NULL);
 307         if (ref) {
 308                 prev_node = rb_prev(&ref->rb_node);
 309                 if (!prev_node)
 310                         goto out;
 311                 ref = rb_entry(prev_node, struct btrfs_delayed_ref_node,
 312                                rb_node);
 313                 if (ref->bytenr == bytenr)
 314                         ret = 1;
 315         }
 316 out:
 317         spin_unlock(&delayed_refs->lock);
 318         return ret;
 319 }
 320
 321 /*
 322  * helper function to update an extent delayed ref in the
 323  * rbtree.  existing and update must both have the same
 324  * bytenr and parent
 325  *
 326  * This may free existing if the update cancels out whatever
 327  * operation it was doing.
 328  */
 329 static noinline void
 330 update_existing_ref(struct btrfs_trans_handle *trans,
 331                     struct btrfs_delayed_ref_root *delayed_refs,
 332                     struct btrfs_delayed_ref_node *existing,
 333                     struct btrfs_delayed_ref_node *update)
 334 {
 335         if (update->action != existing->action) {
 336                 /*
 337                  * this is effectively undoing either an add or a
 338                  * drop.  We decrement the ref_mod, and if it goes
 339                  * down to zero we just delete the entry without
 340                  * every changing the extent allocation tree.
 341                  */
 342                 existing->ref_mod--;
 343                 if (existing->ref_mod == 0) {
 344                         rb_erase(&existing->rb_node,
 345                                  &delayed_refs->root);
 346                         existing->in_tree = 0;
 347                         btrfs_put_delayed_ref(existing);
 348                         delayed_refs->num_entries--;
 349                         if (trans->delayed_ref_updates)
 350                                 trans->delayed_ref_updates--;
 351                 } else {
 352                         WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 353                                 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 354                 }
 355         } else {
 356                 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 357                         existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 358                 /*
 359                  * the action on the existing ref matches
 360                  * the action on the ref we're trying to add.
 361                  * Bump the ref_mod by one so the backref that
 362                  * is eventually added/removed has the correct
 363                  * reference count
 364                  */
 365                 existing->ref_mod += update->ref_mod;
 366         }
 367 }
 368
 369 /*
 370  * helper function to update the accounting in the head ref
 371  * existing and update must have the same bytenr
 372  */
 373 static noinline void
 374 update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
 375                          struct btrfs_delayed_ref_node *update)
 376 {
 377         struct btrfs_delayed_ref_head *existing_ref;
 378         struct btrfs_delayed_ref_head *ref;
 379
 380         existing_ref = btrfs_delayed_node_to_head(existing);
 381         ref = btrfs_delayed_node_to_head(update);
 382         BUG_ON(existing_ref->is_data != ref->is_data);
 383
 384         if (ref->must_insert_reserved) {
 385                 /* if the extent was freed and then
 386                  * reallocated before the delayed ref
 387                  * entries were processed, we can end up
 388                  * with an existing head ref without
 389                  * the must_insert_reserved flag set.
 390                  * Set it again here
 391                  */
 392                 existing_ref->must_insert_reserved = ref->must_insert_reserved;
 393
 394                 /*
 395                  * update the num_bytes so we make sure the accounting
 396                  * is done correctly
 397                  */
 398                 existing->num_bytes = update->num_bytes;
 399
 400         }
 401
 402         if (ref->extent_op) {
 403                 if (!existing_ref->extent_op) {
 404                         existing_ref->extent_op = ref->extent_op;
 405                 } else {
 406                         if (ref->extent_op->update_key) {
 407                                 memcpy(&existing_ref->extent_op->key,
 408                                        &ref->extent_op->key,
 409                                        sizeof(ref->extent_op->key));
 410                                 existing_ref->extent_op->update_key = 1;
 411                         }
 412                         if (ref->extent_op->update_flags) {
 413                                 existing_ref->extent_op->flags_to_set |=
 414                                         ref->extent_op->flags_to_set;
 415                                 existing_ref->extent_op->update_flags = 1;
 416                         }
 417                         kfree(ref->extent_op);
 418                 }
 419         }
 420         /*
 421          * update the reference mod on the head to reflect this new operation
 422          */
 423         existing->ref_mod += update->ref_mod;
 424 }
 425
 426 /*
 427  * helper function to actually insert a head node into the rbtree.
 428  * this does all the dirty work in terms of maintaining the correct
 429  * overall modification count.
 430  */
 431 static noinline int add_delayed_ref_head(struct btrfs_trans_handle *trans,
 432                                         struct btrfs_delayed_ref_node *ref,
 433                                         u64 bytenr, u64 num_bytes,
 434                                         int action, int is_data)
 435 {
 436         struct btrfs_delayed_ref_node *existing;
 437         struct btrfs_delayed_ref_head *head_ref = NULL;
 438         struct btrfs_delayed_ref_root *delayed_refs;
 439         int count_mod = 1;
 440         int must_insert_reserved = 0;
 441
 442         /*
 443          * the head node stores the sum of all the mods, so dropping a ref
 444          * should drop the sum in the head node by one.
 445          */
 446         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 447                 count_mod = 0;
 448         else if (action == BTRFS_DROP_DELAYED_REF)
 449                 count_mod = -1;
 450
 451         /*
 452          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 453          * the reserved accounting when the extent is finally added, or
 454          * if a later modification deletes the delayed ref without ever
 455          * inserting the extent into the extent allocation tree.
 456          * ref->must_insert_reserved is the flag used to record
 457          * that accounting mods are required.
 458          *
 459          * Once we record must_insert_reserved, switch the action to
 460          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 461          */
 462         if (action == BTRFS_ADD_DELAYED_EXTENT)
 463                 must_insert_reserved = 1;
 464         else
 465                 must_insert_reserved = 0;
 466
 467         delayed_refs = &trans->transaction->delayed_refs;
 468
 469         /* first set the basic ref node struct up */
 470         atomic_set(&ref->refs, 1);
 471         ref->bytenr = bytenr;
 472         ref->num_bytes = num_bytes;
 473         ref->ref_mod = count_mod;
 474         ref->type  = 0;
 475         ref->action  = 0;
 476         ref->is_head = 1;
 477         ref->in_tree = 1;
 478
 479         head_ref = btrfs_delayed_node_to_head(ref);
 480         head_ref->must_insert_reserved = must_insert_reserved;
 481         head_ref->is_data = is_data;
 482
 483         INIT_LIST_HEAD(&head_ref->cluster);
 484         mutex_init(&head_ref->mutex);
 485
 486         trace_btrfs_delayed_ref_head(ref, head_ref, action);
 487
 488         existing = tree_insert(&delayed_refs->root, &ref->rb_node);
 489
 490         if (existing) {
 491                 update_existing_head_ref(existing, ref);
 492                 /*
 493                  * we've updated the existing ref, free the newly
 494                  * allocated ref
 495                  */
 496                 kfree(ref);
 497         } else {
 498                 delayed_refs->num_heads++;
 499                 delayed_refs->num_heads_ready++;
 500                 delayed_refs->num_entries++;
 501                 trans->delayed_ref_updates++;
 502         }
 503         return 0;
 504 }
 505
 506 /*
 507  * helper to insert a delayed tree ref into the rbtree.
 508  */
 509 static noinline int add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 510                                          struct btrfs_delayed_ref_node *ref,
 511                                          u64 bytenr, u64 num_bytes, u64 parent,
 512                                          u64 ref_root, int level, int action)
 513 {
 514         struct btrfs_delayed_ref_node *existing;
 515         struct btrfs_delayed_tree_ref *full_ref;
 516         struct btrfs_delayed_ref_root *delayed_refs;
 517
 518         if (action == BTRFS_ADD_DELAYED_EXTENT)
 519                 action = BTRFS_ADD_DELAYED_REF;
 520
 521         delayed_refs = &trans->transaction->delayed_refs;
 522
 523         /* first set the basic ref node struct up */
 524         atomic_set(&ref->refs, 1);
 525         ref->bytenr = bytenr;
 526         ref->num_bytes = num_bytes;
 527         ref->ref_mod = 1;
 528         ref->action = action;
 529         ref->is_head = 0;
 530         ref->in_tree = 1;
 531
 532         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 533         if (parent) {
 534                 full_ref->parent = parent;
 535                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 536         } else {
 537                 full_ref->root = ref_root;
 538                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 539         }
 540         full_ref->level = level;
 541
 542         trace_btrfs_delayed_tree_ref(ref, full_ref, action);
 543
 544         existing = tree_insert(&delayed_refs->root, &ref->rb_node);
 545
 546         if (existing) {
 547                 update_existing_ref(trans, delayed_refs, existing, ref);
 548                 /*
 549                  * we've updated the existing ref, free the newly
 550                  * allocated ref
 551                  */
 552                 kfree(ref);
 553         } else {
 554                 delayed_refs->num_entries++;
 555                 trans->delayed_ref_updates++;
 556         }
 557         return 0;
 558 }
 559
 560 /*
 561  * helper to insert a delayed data ref into the rbtree.
 562  */
 563 static noinline int add_delayed_data_ref(struct btrfs_trans_handle *trans,
 564                                          struct btrfs_delayed_ref_node *ref,
 565                                          u64 bytenr, u64 num_bytes, u64 parent,
 566                                          u64 ref_root, u64 owner, u64 offset,
 567                                          int action)
 568 {
 569         struct btrfs_delayed_ref_node *existing;
 570         struct btrfs_delayed_data_ref *full_ref;
 571         struct btrfs_delayed_ref_root *delayed_refs;
 572
 573         if (action == BTRFS_ADD_DELAYED_EXTENT)
 574                 action = BTRFS_ADD_DELAYED_REF;
 575
 576         delayed_refs = &trans->transaction->delayed_refs;
 577
 578         /* first set the basic ref node struct up */
 579         atomic_set(&ref->refs, 1);
 580         ref->bytenr = bytenr;
 581         ref->num_bytes = num_bytes;
 582         ref->ref_mod = 1;
 583         ref->action = action;
 584         ref->is_head = 0;
 585         ref->in_tree = 1;
 586
 587         full_ref = btrfs_delayed_node_to_data_ref(ref);
 588         if (parent) {
 589                 full_ref->parent = parent;
 590                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 591         } else {
 592                 full_ref->root = ref_root;
 593                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 594         }
 595         full_ref->objectid = owner;
 596         full_ref->offset = offset;
 597
 598         trace_btrfs_delayed_data_ref(ref, full_ref, action);
 599
 600         existing = tree_insert(&delayed_refs->root, &ref->rb_node);
 601
 602         if (existing) {
 603                 update_existing_ref(trans, delayed_refs, existing, ref);
 604                 /*
 605                  * we've updated the existing ref, free the newly
 606                  * allocated ref
 607                  */
 608                 kfree(ref);
 609         } else {
 610                 delayed_refs->num_entries++;
 611                 trans->delayed_ref_updates++;
 612         }
 613         return 0;
 614 }
 615
 616 /*
 617  * add a delayed tree ref.  This does all of the accounting required
 618  * to make sure the delayed ref is eventually processed before this
 619  * transaction commits.
 620  */
 621 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 622                                u64 bytenr, u64 num_bytes, u64 parent,
 623                                u64 ref_root,  int level, int action,
 624                                struct btrfs_delayed_extent_op *extent_op)
 625 {
 626         struct btrfs_delayed_tree_ref *ref;
 627         struct btrfs_delayed_ref_head *head_ref;
 628         struct btrfs_delayed_ref_root *delayed_refs;
 629         int ret;
 630
 631         BUG_ON(extent_op && extent_op->is_data);
 632         ref = kmalloc(sizeof(*ref), GFP_NOFS);
 633         if (!ref)
 634                 return -ENOMEM;
 635
 636         head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
 637         if (!head_ref) {
 638                 kfree(ref);
 639                 return -ENOMEM;
 640         }
 641
 642         head_ref->extent_op = extent_op;
 643
 644         delayed_refs = &trans->transaction->delayed_refs;
 645         spin_lock(&delayed_refs->lock);
 646
 647         /*
 648          * insert both the head node and the new ref without dropping
 649          * the spin lock
 650          */
 651         ret = add_delayed_ref_head(trans, &head_ref->node, bytenr, num_bytes,
 652                                    action, 0);
 653         BUG_ON(ret);
 654
 655         ret = add_delayed_tree_ref(trans, &ref->node, bytenr, num_bytes,
 656                                    parent, ref_root, level, action);
 657         BUG_ON(ret);
 658         spin_unlock(&delayed_refs->lock);
 659         return 0;
 660 }
 661
 662 /*
 663  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 664  */
 665 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
 666                                u64 bytenr, u64 num_bytes,
 667                                u64 parent, u64 ref_root,
 668                                u64 owner, u64 offset, int action,
 669                                struct btrfs_delayed_extent_op *extent_op)
 670 {
 671         struct btrfs_delayed_data_ref *ref;
 672         struct btrfs_delayed_ref_head *head_ref;
 673         struct btrfs_delayed_ref_root *delayed_refs;
 674         int ret;
 675
 676         BUG_ON(extent_op && !extent_op->is_data);
 677         ref = kmalloc(sizeof(*ref), GFP_NOFS);
 678         if (!ref)
 679                 return -ENOMEM;
 680
 681         head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
 682         if (!head_ref) {
 683                 kfree(ref);
 684                 return -ENOMEM;
 685         }
 686
 687         head_ref->extent_op = extent_op;
 688
 689         delayed_refs = &trans->transaction->delayed_refs;
 690         spin_lock(&delayed_refs->lock);
 691
 692         /*
 693          * insert both the head node and the new ref without dropping
 694          * the spin lock
 695          */
 696         ret = add_delayed_ref_head(trans, &head_ref->node, bytenr, num_bytes,
 697                                    action, 1);
 698         BUG_ON(ret);
 699
 700         ret = add_delayed_data_ref(trans, &ref->node, bytenr, num_bytes,
 701                                    parent, ref_root, owner, offset, action);
 702         BUG_ON(ret);
 703         spin_unlock(&delayed_refs->lock);
 704         return 0;
 705 }
 706
 707 int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
 708                                 u64 bytenr, u64 num_bytes,
 709                                 struct btrfs_delayed_extent_op *extent_op)
 710 {
 711         struct btrfs_delayed_ref_head *head_ref;
 712         struct btrfs_delayed_ref_root *delayed_refs;
 713         int ret;
 714
 715         head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
 716         if (!head_ref)
 717                 return -ENOMEM;
 718
 719         head_ref->extent_op = extent_op;
 720
 721         delayed_refs = &trans->transaction->delayed_refs;
 722         spin_lock(&delayed_refs->lock);
 723
 724         ret = add_delayed_ref_head(trans, &head_ref->node, bytenr,
 725                                    num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
 726                                    extent_op->is_data);
 727         BUG_ON(ret);
 728
 729         spin_unlock(&delayed_refs->lock);
 730         return 0;
 731 }
 732
 733 /*
 734  * this does a simple search for the head node for a given extent.
 735  * It must be called with the delayed ref spinlock held, and it returns
 736  * the head node if any where found, or NULL if not.
 737  */
 738 struct btrfs_delayed_ref_head *
 739 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
 740 {
 741         struct btrfs_delayed_ref_node *ref;
 742         struct btrfs_delayed_ref_root *delayed_refs;
 743
 744         delayed_refs = &trans->transaction->delayed_refs;
 745         ref = find_ref_head(&delayed_refs->root, bytenr, NULL);
 746         if (ref)
 747                 return btrfs_delayed_node_to_head(ref);
 748         return NULL;
 749 }
 750
 751 /*
 752  * add a delayed ref to the tree.  This does all of the accounting required
 753  * to make sure the delayed ref is eventually processed before this
 754  * transaction commits.
 755  *
 756  * The main point of this call is to add and remove a backreference in a single
 757  * shot, taking the lock only once, and only searching for the head node once.
 758  *
 759  * It is the same as doing a ref add and delete in two separate calls.
 760  */
 761 #if 0
 762 int btrfs_update_delayed_ref(struct btrfs_trans_handle *trans,
 763                           u64 bytenr, u64 num_bytes, u64 orig_parent,
 764                           u64 parent, u64 orig_ref_root, u64 ref_root,
 765                           u64 orig_ref_generation, u64 ref_generation,
 766                           u64 owner_objectid, int pin)
 767 {
 768         struct btrfs_delayed_ref *ref;
 769         struct btrfs_delayed_ref *old_ref;
 770         struct btrfs_delayed_ref_head *head_ref;
 771         struct btrfs_delayed_ref_root *delayed_refs;
 772         int ret;
 773
 774         ref = kmalloc(sizeof(*ref), GFP_NOFS);
 775         if (!ref)
 776                 return -ENOMEM;
 777
 778         old_ref = kmalloc(sizeof(*old_ref), GFP_NOFS);
 779         if (!old_ref) {
 780                 kfree(ref);
 781                 return -ENOMEM;
 782         }
 783
 784         /*
 785          * the parent = 0 case comes from cases where we don't actually
 786          * know the parent yet.  It will get updated later via a add/drop
 787          * pair.
 788          */
 789         if (parent == 0)
 790                 parent = bytenr;
 791         if (orig_parent == 0)
 792                 orig_parent = bytenr;
 793
 794         head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
 795         if (!head_ref) {
 796                 kfree(ref);
 797                 kfree(old_ref);
 798                 return -ENOMEM;
 799         }
 800         delayed_refs = &trans->transaction->delayed_refs;
 801         spin_lock(&delayed_refs->lock);
 802
 803         /*
 804          * insert both the head node and the new ref without dropping
 805          * the spin lock
 806          */
 807         ret = __btrfs_add_delayed_ref(trans, &head_ref->node, bytenr, num_bytes,
 808                                       (u64)-1, 0, 0, 0,
 809                                       BTRFS_UPDATE_DELAYED_HEAD, 0);
 810         BUG_ON(ret);
 811
 812         ret = __btrfs_add_delayed_ref(trans, &ref->node, bytenr, num_bytes,
 813                                       parent, ref_root, ref_generation,
 814                                       owner_objectid, BTRFS_ADD_DELAYED_REF, 0);
 815         BUG_ON(ret);
 816
 817         ret = __btrfs_add_delayed_ref(trans, &old_ref->node, bytenr, num_bytes,
 818                                       orig_parent, orig_ref_root,
 819                                       orig_ref_generation, owner_objectid,
 820                                       BTRFS_DROP_DELAYED_REF, pin);
 821         BUG_ON(ret);
 822         spin_unlock(&delayed_refs->lock);
 823         return 0;
 824 }
 825 #endif