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 #include "qgroup.h"
  26
  27 struct kmem_cache *btrfs_delayed_ref_head_cachep;
  28 struct kmem_cache *btrfs_delayed_tree_ref_cachep;
  29 struct kmem_cache *btrfs_delayed_data_ref_cachep;
  30 struct kmem_cache *btrfs_delayed_extent_op_cachep;
  31 /*
  32  * delayed back reference update tracking.  For subvolume trees
  33  * we queue up extent allocations and backref maintenance for
  34  * delayed processing.   This avoids deep call chains where we
  35  * add extents in the middle of btrfs_search_slot, and it allows
  36  * us to buffer up frequently modified backrefs in an rb tree instead
  37  * of hammering updates on the extent allocation tree.
  38  */
  39
  40 /*
  41  * compare two delayed tree backrefs with same bytenr and type
  42  */
  43 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
  44                           struct btrfs_delayed_tree_ref *ref1, int type)
  45 {
  46         if (type == BTRFS_TREE_BLOCK_REF_KEY) {
  47                 if (ref1->root < ref2->root)
  48                         return -1;
  49                 if (ref1->root > ref2->root)
  50                         return 1;
  51         } else {
  52                 if (ref1->parent < ref2->parent)
  53                         return -1;
  54                 if (ref1->parent > ref2->parent)
  55                         return 1;
  56         }
  57         return 0;
  58 }
  59
  60 /*
  61  * compare two delayed data backrefs with same bytenr and type
  62  */
  63 static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
  64                           struct btrfs_delayed_data_ref *ref1)
  65 {
  66         if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
  67                 if (ref1->root < ref2->root)
  68                         return -1;
  69                 if (ref1->root > ref2->root)
  70                         return 1;
  71                 if (ref1->objectid < ref2->objectid)
  72                         return -1;
  73                 if (ref1->objectid > ref2->objectid)
  74                         return 1;
  75                 if (ref1->offset < ref2->offset)
  76                         return -1;
  77                 if (ref1->offset > ref2->offset)
  78                         return 1;
  79         } else {
  80                 if (ref1->parent < ref2->parent)
  81                         return -1;
  82                 if (ref1->parent > ref2->parent)
  83                         return 1;
  84         }
  85         return 0;
  86 }
  87
  88 /* insert a new ref to head ref rbtree */
  89 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
  90                                                    struct rb_node *node)
  91 {
  92         struct rb_node **p = &root->rb_node;
  93         struct rb_node *parent_node = NULL;
  94         struct btrfs_delayed_ref_head *entry;
  95         struct btrfs_delayed_ref_head *ins;
  96         u64 bytenr;
  97
  98         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
  99         bytenr = ins->node.bytenr;
 100         while (*p) {
 101                 parent_node = *p;
 102                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
 103                                  href_node);
 104
 105                 if (bytenr < entry->node.bytenr)
 106                         p = &(*p)->rb_left;
 107                 else if (bytenr > entry->node.bytenr)
 108                         p = &(*p)->rb_right;
 109                 else
 110                         return entry;
 111         }
 112
 113         rb_link_node(node, parent_node, p);
 114         rb_insert_color(node, root);
 115         return NULL;
 116 }
 117
 118 /*
 119  * find an head entry based on bytenr. This returns the delayed ref
 120  * head if it was able to find one, or NULL if nothing was in that spot.
 121  * If return_bigger is given, the next bigger entry is returned if no exact
 122  * match is found.
 123  */
 124 static struct btrfs_delayed_ref_head *
 125 find_ref_head(struct rb_root *root, u64 bytenr,
 126               int return_bigger)
 127 {
 128         struct rb_node *n;
 129         struct btrfs_delayed_ref_head *entry;
 130
 131         n = root->rb_node;
 132         entry = NULL;
 133         while (n) {
 134                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
 135
 136                 if (bytenr < entry->node.bytenr)
 137                         n = n->rb_left;
 138                 else if (bytenr > entry->node.bytenr)
 139                         n = n->rb_right;
 140                 else
 141                         return entry;
 142         }
 143         if (entry && return_bigger) {
 144                 if (bytenr > entry->node.bytenr) {
 145                         n = rb_next(&entry->href_node);
 146                         if (!n)
 147                                 n = rb_first(root);
 148                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
 149                                          href_node);
 150                         return entry;
 151                 }
 152                 return entry;
 153         }
 154         return NULL;
 155 }
 156
 157 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 158                            struct btrfs_delayed_ref_head *head)
 159 {
 160         struct btrfs_delayed_ref_root *delayed_refs;
 161
 162         delayed_refs = &trans->transaction->delayed_refs;
 163         assert_spin_locked(&delayed_refs->lock);
 164         if (mutex_trylock(&head->mutex))
 165                 return 0;
 166
 167         atomic_inc(&head->node.refs);
 168         spin_unlock(&delayed_refs->lock);
 169
 170         mutex_lock(&head->mutex);
 171         spin_lock(&delayed_refs->lock);
 172         if (!head->node.in_tree) {
 173                 mutex_unlock(&head->mutex);
 174                 btrfs_put_delayed_ref(&head->node);
 175                 return -EAGAIN;
 176         }
 177         btrfs_put_delayed_ref(&head->node);
 178         return 0;
 179 }
 180
 181 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 182                                     struct btrfs_delayed_ref_root *delayed_refs,
 183                                     struct btrfs_delayed_ref_head *head,
 184                                     struct btrfs_delayed_ref_node *ref)
 185 {
 186         if (btrfs_delayed_ref_is_head(ref)) {
 187                 head = btrfs_delayed_node_to_head(ref);
 188                 rb_erase(&head->href_node, &delayed_refs->href_root);
 189         } else {
 190                 assert_spin_locked(&head->lock);
 191                 list_del(&ref->list);
 192                 if (!list_empty(&ref->add_list))
 193                         list_del(&ref->add_list);
 194         }
 195         ref->in_tree = 0;
 196         btrfs_put_delayed_ref(ref);
 197         atomic_dec(&delayed_refs->num_entries);
 198         if (trans->delayed_ref_updates)
 199                 trans->delayed_ref_updates--;
 200 }
 201
 202 static bool merge_ref(struct btrfs_trans_handle *trans,
 203                       struct btrfs_delayed_ref_root *delayed_refs,
 204                       struct btrfs_delayed_ref_head *head,
 205                       struct btrfs_delayed_ref_node *ref,
 206                       u64 seq)
 207 {
 208         struct btrfs_delayed_ref_node *next;
 209         bool done = false;
 210
 211         next = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
 212                                 list);
 213         while (!done && &next->list != &head->ref_list) {
 214                 int mod;
 215                 struct btrfs_delayed_ref_node *next2;
 216
 217                 next2 = list_next_entry(next, list);
 218
 219                 if (next == ref)
 220                         goto next;
 221
 222                 if (seq && next->seq >= seq)
 223                         goto next;
 224
 225                 if (next->type != ref->type)
 226                         goto next;
 227
 228                 if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 229                      ref->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
 230                     comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref),
 231                                    btrfs_delayed_node_to_tree_ref(next),
 232                                    ref->type))
 233                         goto next;
 234                 if ((ref->type == BTRFS_EXTENT_DATA_REF_KEY ||
 235                      ref->type == BTRFS_SHARED_DATA_REF_KEY) &&
 236                     comp_data_refs(btrfs_delayed_node_to_data_ref(ref),
 237                                    btrfs_delayed_node_to_data_ref(next)))
 238                         goto next;
 239
 240                 if (ref->action == next->action) {
 241                         mod = next->ref_mod;
 242                 } else {
 243                         if (ref->ref_mod < next->ref_mod) {
 244                                 swap(ref, next);
 245                                 done = true;
 246                         }
 247                         mod = -next->ref_mod;
 248                 }
 249
 250                 drop_delayed_ref(trans, delayed_refs, head, next);
 251                 ref->ref_mod += mod;
 252                 if (ref->ref_mod == 0) {
 253                         drop_delayed_ref(trans, delayed_refs, head, ref);
 254                         done = true;
 255                 } else {
 256                         /*
 257                          * Can't have multiples of the same ref on a tree block.
 258                          */
 259                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 260                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 261                 }
 262 next:
 263                 next = next2;
 264         }
 265
 266         return done;
 267 }
 268
 269 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 270                               struct btrfs_fs_info *fs_info,
 271                               struct btrfs_delayed_ref_root *delayed_refs,
 272                               struct btrfs_delayed_ref_head *head)
 273 {
 274         struct btrfs_delayed_ref_node *ref;
 275         u64 seq = 0;
 276
 277         assert_spin_locked(&head->lock);
 278
 279         if (list_empty(&head->ref_list))
 280                 return;
 281
 282         /* We don't have too many refs to merge for data. */
 283         if (head->is_data)
 284                 return;
 285
 286         spin_lock(&fs_info->tree_mod_seq_lock);
 287         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 288                 struct seq_list *elem;
 289
 290                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 291                                         struct seq_list, list);
 292                 seq = elem->seq;
 293         }
 294         spin_unlock(&fs_info->tree_mod_seq_lock);
 295
 296         ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
 297                                list);
 298         while (&ref->list != &head->ref_list) {
 299                 if (seq && ref->seq >= seq)
 300                         goto next;
 301
 302                 if (merge_ref(trans, delayed_refs, head, ref, seq)) {
 303                         if (list_empty(&head->ref_list))
 304                                 break;
 305                         ref = list_first_entry(&head->ref_list,
 306                                                struct btrfs_delayed_ref_node,
 307                                                list);
 308                         continue;
 309                 }
 310 next:
 311                 ref = list_next_entry(ref, list);
 312         }
 313 }
 314
 315 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 316                             struct btrfs_delayed_ref_root *delayed_refs,
 317                             u64 seq)
 318 {
 319         struct seq_list *elem;
 320         int ret = 0;
 321
 322         spin_lock(&fs_info->tree_mod_seq_lock);
 323         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 324                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 325                                         struct seq_list, list);
 326                 if (seq >= elem->seq) {
 327                         btrfs_debug(fs_info,
 328                                 "holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)",
 329                                 (u32)(seq >> 32), (u32)seq,
 330                                 (u32)(elem->seq >> 32), (u32)elem->seq,
 331                                 delayed_refs);
 332                         ret = 1;
 333                 }
 334         }
 335
 336         spin_unlock(&fs_info->tree_mod_seq_lock);
 337         return ret;
 338 }
 339
 340 struct btrfs_delayed_ref_head *
 341 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 342 {
 343         struct btrfs_delayed_ref_root *delayed_refs;
 344         struct btrfs_delayed_ref_head *head;
 345         u64 start;
 346         bool loop = false;
 347
 348         delayed_refs = &trans->transaction->delayed_refs;
 349
 350 again:
 351         start = delayed_refs->run_delayed_start;
 352         head = find_ref_head(&delayed_refs->href_root, start, 1);
 353         if (!head && !loop) {
 354                 delayed_refs->run_delayed_start = 0;
 355                 start = 0;
 356                 loop = true;
 357                 head = find_ref_head(&delayed_refs->href_root, start, 1);
 358                 if (!head)
 359                         return NULL;
 360         } else if (!head && loop) {
 361                 return NULL;
 362         }
 363
 364         while (head->processing) {
 365                 struct rb_node *node;
 366
 367                 node = rb_next(&head->href_node);
 368                 if (!node) {
 369                         if (loop)
 370                                 return NULL;
 371                         delayed_refs->run_delayed_start = 0;
 372                         start = 0;
 373                         loop = true;
 374                         goto again;
 375                 }
 376                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 377                                 href_node);
 378         }
 379
 380         head->processing = 1;
 381         WARN_ON(delayed_refs->num_heads_ready == 0);
 382         delayed_refs->num_heads_ready--;
 383         delayed_refs->run_delayed_start = head->node.bytenr +
 384                 head->node.num_bytes;
 385         return head;
 386 }
 387
 388 /*
 389  * Helper to insert the ref_node to the tail or merge with tail.
 390  *
 391  * Return 0 for insert.
 392  * Return >0 for merge.
 393  */
 394 static int
 395 add_delayed_ref_tail_merge(struct btrfs_trans_handle *trans,
 396                            struct btrfs_delayed_ref_root *root,
 397                            struct btrfs_delayed_ref_head *href,
 398                            struct btrfs_delayed_ref_node *ref)
 399 {
 400         struct btrfs_delayed_ref_node *exist;
 401         int mod;
 402         int ret = 0;
 403
 404         spin_lock(&href->lock);
 405         /* Check whether we can merge the tail node with ref */
 406         if (list_empty(&href->ref_list))
 407                 goto add_tail;
 408         exist = list_entry(href->ref_list.prev, struct btrfs_delayed_ref_node,
 409                            list);
 410         /* No need to compare bytenr nor is_head */
 411         if (exist->type != ref->type || exist->seq != ref->seq)
 412                 goto add_tail;
 413
 414         if ((exist->type == BTRFS_TREE_BLOCK_REF_KEY ||
 415              exist->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
 416             comp_tree_refs(btrfs_delayed_node_to_tree_ref(exist),
 417                            btrfs_delayed_node_to_tree_ref(ref),
 418                            ref->type))
 419                 goto add_tail;
 420         if ((exist->type == BTRFS_EXTENT_DATA_REF_KEY ||
 421              exist->type == BTRFS_SHARED_DATA_REF_KEY) &&
 422             comp_data_refs(btrfs_delayed_node_to_data_ref(exist),
 423                            btrfs_delayed_node_to_data_ref(ref)))
 424                 goto add_tail;
 425
 426         /* Now we are sure we can merge */
 427         ret = 1;
 428         if (exist->action == ref->action) {
 429                 mod = ref->ref_mod;
 430         } else {
 431                 /* Need to change action */
 432                 if (exist->ref_mod < ref->ref_mod) {
 433                         exist->action = ref->action;
 434                         mod = -exist->ref_mod;
 435                         exist->ref_mod = ref->ref_mod;
 436                         if (ref->action == BTRFS_ADD_DELAYED_REF)
 437                                 list_add_tail(&exist->add_list,
 438                                               &href->ref_add_list);
 439                         else if (ref->action == BTRFS_DROP_DELAYED_REF) {
 440                                 ASSERT(!list_empty(&exist->add_list));
 441                                 list_del(&exist->add_list);
 442                         } else {
 443                                 ASSERT(0);
 444                         }
 445                 } else
 446                         mod = -ref->ref_mod;
 447         }
 448         exist->ref_mod += mod;
 449
 450         /* remove existing tail if its ref_mod is zero */
 451         if (exist->ref_mod == 0)
 452                 drop_delayed_ref(trans, root, href, exist);
 453         spin_unlock(&href->lock);
 454         return ret;
 455
 456 add_tail:
 457         list_add_tail(&ref->list, &href->ref_list);
 458         if (ref->action == BTRFS_ADD_DELAYED_REF)
 459                 list_add_tail(&ref->add_list, &href->ref_add_list);
 460         atomic_inc(&root->num_entries);
 461         trans->delayed_ref_updates++;
 462         spin_unlock(&href->lock);
 463         return ret;
 464 }
 465
 466 /*
 467  * helper function to update the accounting in the head ref
 468  * existing and update must have the same bytenr
 469  */
 470 static noinline void
 471 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
 472                          struct btrfs_delayed_ref_node *existing,
 473                          struct btrfs_delayed_ref_node *update)
 474 {
 475         struct btrfs_delayed_ref_head *existing_ref;
 476         struct btrfs_delayed_ref_head *ref;
 477         int old_ref_mod;
 478
 479         existing_ref = btrfs_delayed_node_to_head(existing);
 480         ref = btrfs_delayed_node_to_head(update);
 481         BUG_ON(existing_ref->is_data != ref->is_data);
 482
 483         spin_lock(&existing_ref->lock);
 484         if (ref->must_insert_reserved) {
 485                 /* if the extent was freed and then
 486                  * reallocated before the delayed ref
 487                  * entries were processed, we can end up
 488                  * with an existing head ref without
 489                  * the must_insert_reserved flag set.
 490                  * Set it again here
 491                  */
 492                 existing_ref->must_insert_reserved = ref->must_insert_reserved;
 493
 494                 /*
 495                  * update the num_bytes so we make sure the accounting
 496                  * is done correctly
 497                  */
 498                 existing->num_bytes = update->num_bytes;
 499
 500         }
 501
 502         if (ref->extent_op) {
 503                 if (!existing_ref->extent_op) {
 504                         existing_ref->extent_op = ref->extent_op;
 505                 } else {
 506                         if (ref->extent_op->update_key) {
 507                                 memcpy(&existing_ref->extent_op->key,
 508                                        &ref->extent_op->key,
 509                                        sizeof(ref->extent_op->key));
 510                                 existing_ref->extent_op->update_key = true;
 511                         }
 512                         if (ref->extent_op->update_flags) {
 513                                 existing_ref->extent_op->flags_to_set |=
 514                                         ref->extent_op->flags_to_set;
 515                                 existing_ref->extent_op->update_flags = true;
 516                         }
 517                         btrfs_free_delayed_extent_op(ref->extent_op);
 518                 }
 519         }
 520         /*
 521          * update the reference mod on the head to reflect this new operation,
 522          * only need the lock for this case cause we could be processing it
 523          * currently, for refs we just added we know we're a-ok.
 524          */
 525         old_ref_mod = existing_ref->total_ref_mod;
 526         existing->ref_mod += update->ref_mod;
 527         existing_ref->total_ref_mod += update->ref_mod;
 528
 529         /*
 530          * If we are going to from a positive ref mod to a negative or vice
 531          * versa we need to make sure to adjust pending_csums accordingly.
 532          */
 533         if (existing_ref->is_data) {
 534                 if (existing_ref->total_ref_mod >= 0 && old_ref_mod < 0)
 535                         delayed_refs->pending_csums -= existing->num_bytes;
 536                 if (existing_ref->total_ref_mod < 0 && old_ref_mod >= 0)
 537                         delayed_refs->pending_csums += existing->num_bytes;
 538         }
 539         spin_unlock(&existing_ref->lock);
 540 }
 541
 542 /*
 543  * helper function to actually insert a head node into the rbtree.
 544  * this does all the dirty work in terms of maintaining the correct
 545  * overall modification count.
 546  */
 547 static noinline struct btrfs_delayed_ref_head *
 548 add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 549                      struct btrfs_trans_handle *trans,
 550                      struct btrfs_delayed_ref_node *ref,
 551                      struct btrfs_qgroup_extent_record *qrecord,
 552                      u64 bytenr, u64 num_bytes, u64 ref_root, u64 reserved,
 553                      int action, int is_data)
 554 {
 555         struct btrfs_delayed_ref_head *existing;
 556         struct btrfs_delayed_ref_head *head_ref = NULL;
 557         struct btrfs_delayed_ref_root *delayed_refs;
 558         int count_mod = 1;
 559         int must_insert_reserved = 0;
 560
 561         /* If reserved is provided, it must be a data extent. */
 562         BUG_ON(!is_data && reserved);
 563
 564         /*
 565          * the head node stores the sum of all the mods, so dropping a ref
 566          * should drop the sum in the head node by one.
 567          */
 568         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 569                 count_mod = 0;
 570         else if (action == BTRFS_DROP_DELAYED_REF)
 571                 count_mod = -1;
 572
 573         /*
 574          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 575          * the reserved accounting when the extent is finally added, or
 576          * if a later modification deletes the delayed ref without ever
 577          * inserting the extent into the extent allocation tree.
 578          * ref->must_insert_reserved is the flag used to record
 579          * that accounting mods are required.
 580          *
 581          * Once we record must_insert_reserved, switch the action to
 582          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 583          */
 584         if (action == BTRFS_ADD_DELAYED_EXTENT)
 585                 must_insert_reserved = 1;
 586         else
 587                 must_insert_reserved = 0;
 588
 589         delayed_refs = &trans->transaction->delayed_refs;
 590
 591         /* first set the basic ref node struct up */
 592         atomic_set(&ref->refs, 1);
 593         ref->bytenr = bytenr;
 594         ref->num_bytes = num_bytes;
 595         ref->ref_mod = count_mod;
 596         ref->type  = 0;
 597         ref->action  = 0;
 598         ref->is_head = 1;
 599         ref->in_tree = 1;
 600         ref->seq = 0;
 601
 602         head_ref = btrfs_delayed_node_to_head(ref);
 603         head_ref->must_insert_reserved = must_insert_reserved;
 604         head_ref->is_data = is_data;
 605         INIT_LIST_HEAD(&head_ref->ref_list);
 606         INIT_LIST_HEAD(&head_ref->ref_add_list);
 607         head_ref->processing = 0;
 608         head_ref->total_ref_mod = count_mod;
 609         head_ref->qgroup_reserved = 0;
 610         head_ref->qgroup_ref_root = 0;
 611
 612         /* Record qgroup extent info if provided */
 613         if (qrecord) {
 614                 if (ref_root && reserved) {
 615                         head_ref->qgroup_ref_root = ref_root;
 616                         head_ref->qgroup_reserved = reserved;
 617                 }
 618
 619                 qrecord->bytenr = bytenr;
 620                 qrecord->num_bytes = num_bytes;
 621                 qrecord->old_roots = NULL;
 622
 623                 if(btrfs_qgroup_trace_extent_nolock(fs_info,
 624                                         delayed_refs, qrecord))
 625                         kfree(qrecord);
 626         }
 627
 628         spin_lock_init(&head_ref->lock);
 629         mutex_init(&head_ref->mutex);
 630
 631         trace_add_delayed_ref_head(fs_info, ref, head_ref, action);
 632
 633         existing = htree_insert(&delayed_refs->href_root,
 634                                 &head_ref->href_node);
 635         if (existing) {
 636                 WARN_ON(ref_root && reserved && existing->qgroup_ref_root
 637                         && existing->qgroup_reserved);
 638                 update_existing_head_ref(delayed_refs, &existing->node, ref);
 639                 /*
 640                  * we've updated the existing ref, free the newly
 641                  * allocated ref
 642                  */
 643                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 644                 head_ref = existing;
 645         } else {
 646                 if (is_data && count_mod < 0)
 647                         delayed_refs->pending_csums += num_bytes;
 648                 delayed_refs->num_heads++;
 649                 delayed_refs->num_heads_ready++;
 650                 atomic_inc(&delayed_refs->num_entries);
 651                 trans->delayed_ref_updates++;
 652         }
 653         return head_ref;
 654 }
 655
 656 /*
 657  * helper to insert a delayed tree ref into the rbtree.
 658  */
 659 static noinline void
 660 add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 661                      struct btrfs_trans_handle *trans,
 662                      struct btrfs_delayed_ref_head *head_ref,
 663                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 664                      u64 num_bytes, u64 parent, u64 ref_root, int level,
 665                      int action)
 666 {
 667         struct btrfs_delayed_tree_ref *full_ref;
 668         struct btrfs_delayed_ref_root *delayed_refs;
 669         u64 seq = 0;
 670         int ret;
 671
 672         if (action == BTRFS_ADD_DELAYED_EXTENT)
 673                 action = BTRFS_ADD_DELAYED_REF;
 674
 675         if (is_fstree(ref_root))
 676                 seq = atomic64_read(&fs_info->tree_mod_seq);
 677         delayed_refs = &trans->transaction->delayed_refs;
 678
 679         /* first set the basic ref node struct up */
 680         atomic_set(&ref->refs, 1);
 681         ref->bytenr = bytenr;
 682         ref->num_bytes = num_bytes;
 683         ref->ref_mod = 1;
 684         ref->action = action;
 685         ref->is_head = 0;
 686         ref->in_tree = 1;
 687         ref->seq = seq;
 688         INIT_LIST_HEAD(&ref->list);
 689         INIT_LIST_HEAD(&ref->add_list);
 690
 691         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 692         full_ref->parent = parent;
 693         full_ref->root = ref_root;
 694         if (parent)
 695                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 696         else
 697                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 698         full_ref->level = level;
 699
 700         trace_add_delayed_tree_ref(fs_info, ref, full_ref, action);
 701
 702         ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
 703
 704         /*
 705          * XXX: memory should be freed at the same level allocated.
 706          * But bad practice is anywhere... Follow it now. Need cleanup.
 707          */
 708         if (ret > 0)
 709                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 710 }
 711
 712 /*
 713  * helper to insert a delayed data ref into the rbtree.
 714  */
 715 static noinline void
 716 add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 717                      struct btrfs_trans_handle *trans,
 718                      struct btrfs_delayed_ref_head *head_ref,
 719                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 720                      u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
 721                      u64 offset, int action)
 722 {
 723         struct btrfs_delayed_data_ref *full_ref;
 724         struct btrfs_delayed_ref_root *delayed_refs;
 725         u64 seq = 0;
 726         int ret;
 727
 728         if (action == BTRFS_ADD_DELAYED_EXTENT)
 729                 action = BTRFS_ADD_DELAYED_REF;
 730
 731         delayed_refs = &trans->transaction->delayed_refs;
 732
 733         if (is_fstree(ref_root))
 734                 seq = atomic64_read(&fs_info->tree_mod_seq);
 735
 736         /* first set the basic ref node struct up */
 737         atomic_set(&ref->refs, 1);
 738         ref->bytenr = bytenr;
 739         ref->num_bytes = num_bytes;
 740         ref->ref_mod = 1;
 741         ref->action = action;
 742         ref->is_head = 0;
 743         ref->in_tree = 1;
 744         ref->seq = seq;
 745         INIT_LIST_HEAD(&ref->list);
 746         INIT_LIST_HEAD(&ref->add_list);
 747
 748         full_ref = btrfs_delayed_node_to_data_ref(ref);
 749         full_ref->parent = parent;
 750         full_ref->root = ref_root;
 751         if (parent)
 752                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 753         else
 754                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 755
 756         full_ref->objectid = owner;
 757         full_ref->offset = offset;
 758
 759         trace_add_delayed_data_ref(fs_info, ref, full_ref, action);
 760
 761         ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
 762
 763         if (ret > 0)
 764                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 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 {
 778         struct btrfs_delayed_tree_ref *ref;
 779         struct btrfs_delayed_ref_head *head_ref;
 780         struct btrfs_delayed_ref_root *delayed_refs;
 781         struct btrfs_qgroup_extent_record *record = NULL;
 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                 goto free_ref;
 791
 792         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 793             is_fstree(ref_root)) {
 794                 record = kmalloc(sizeof(*record), GFP_NOFS);
 795                 if (!record)
 796                         goto free_head_ref;
 797         }
 798
 799         head_ref->extent_op = extent_op;
 800
 801         delayed_refs = &trans->transaction->delayed_refs;
 802         spin_lock(&delayed_refs->lock);
 803
 804         /*
 805          * insert both the head node and the new ref without dropping
 806          * the spin lock
 807          */
 808         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
 809                                         bytenr, num_bytes, 0, 0, action, 0);
 810
 811         add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 812                              num_bytes, parent, ref_root, level, action);
 813         spin_unlock(&delayed_refs->lock);
 814
 815         return 0;
 816
 817 free_head_ref:
 818         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 819 free_ref:
 820         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 821
 822         return -ENOMEM;
 823 }
 824
 825 /*
 826  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 827  */
 828 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 829                                struct btrfs_trans_handle *trans,
 830                                u64 bytenr, u64 num_bytes,
 831                                u64 parent, u64 ref_root,
 832                                u64 owner, u64 offset, u64 reserved, int action,
 833                                struct btrfs_delayed_extent_op *extent_op)
 834 {
 835         struct btrfs_delayed_data_ref *ref;
 836         struct btrfs_delayed_ref_head *head_ref;
 837         struct btrfs_delayed_ref_root *delayed_refs;
 838         struct btrfs_qgroup_extent_record *record = NULL;
 839
 840         BUG_ON(extent_op && !extent_op->is_data);
 841         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 842         if (!ref)
 843                 return -ENOMEM;
 844
 845         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 846         if (!head_ref) {
 847                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 848                 return -ENOMEM;
 849         }
 850
 851         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 852             is_fstree(ref_root)) {
 853                 record = kmalloc(sizeof(*record), GFP_NOFS);
 854                 if (!record) {
 855                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 856                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
 857                                         head_ref);
 858                         return -ENOMEM;
 859                 }
 860         }
 861
 862         head_ref->extent_op = extent_op;
 863
 864         delayed_refs = &trans->transaction->delayed_refs;
 865         spin_lock(&delayed_refs->lock);
 866
 867         /*
 868          * insert both the head node and the new ref without dropping
 869          * the spin lock
 870          */
 871         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
 872                                         bytenr, num_bytes, ref_root, reserved,
 873                                         action, 1);
 874
 875         add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 876                                    num_bytes, parent, ref_root, owner, offset,
 877                                    action);
 878         spin_unlock(&delayed_refs->lock);
 879
 880         return 0;
 881 }
 882
 883 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 884                                 struct btrfs_trans_handle *trans,
 885                                 u64 bytenr, u64 num_bytes,
 886                                 struct btrfs_delayed_extent_op *extent_op)
 887 {
 888         struct btrfs_delayed_ref_head *head_ref;
 889         struct btrfs_delayed_ref_root *delayed_refs;
 890
 891         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 892         if (!head_ref)
 893                 return -ENOMEM;
 894
 895         head_ref->extent_op = extent_op;
 896
 897         delayed_refs = &trans->transaction->delayed_refs;
 898         spin_lock(&delayed_refs->lock);
 899
 900         add_delayed_ref_head(fs_info, trans, &head_ref->node, NULL, bytenr,
 901                              num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,
 902                              extent_op->is_data);
 903
 904         spin_unlock(&delayed_refs->lock);
 905         return 0;
 906 }
 907
 908 /*
 909  * this does a simple search for the head node for a given extent.
 910  * It must be called with the delayed ref spinlock held, and it returns
 911  * the head node if any where found, or NULL if not.
 912  */
 913 struct btrfs_delayed_ref_head *
 914 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
 915 {
 916         struct btrfs_delayed_ref_root *delayed_refs;
 917
 918         delayed_refs = &trans->transaction->delayed_refs;
 919         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
 920 }
 921
 922 void btrfs_delayed_ref_exit(void)
 923 {
 924         kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 925         kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 926         kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 927         kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 928 }
 929
 930 int btrfs_delayed_ref_init(void)
 931 {
 932         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 933                                 "btrfs_delayed_ref_head",
 934                                 sizeof(struct btrfs_delayed_ref_head), 0,
 935                                 SLAB_MEM_SPREAD, NULL);
 936         if (!btrfs_delayed_ref_head_cachep)
 937                 goto fail;
 938
 939         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 940                                 "btrfs_delayed_tree_ref",
 941                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 942                                 SLAB_MEM_SPREAD, NULL);
 943         if (!btrfs_delayed_tree_ref_cachep)
 944                 goto fail;
 945
 946         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 947                                 "btrfs_delayed_data_ref",
 948                                 sizeof(struct btrfs_delayed_data_ref), 0,
 949                                 SLAB_MEM_SPREAD, NULL);
 950         if (!btrfs_delayed_data_ref_cachep)
 951                 goto fail;
 952
 953         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 954                                 "btrfs_delayed_extent_op",
 955                                 sizeof(struct btrfs_delayed_extent_op), 0,
 956                                 SLAB_MEM_SPREAD, NULL);
 957         if (!btrfs_delayed_extent_op_cachep)
 958                 goto fail;
 959
 960         return 0;
 961 fail:
 962         btrfs_delayed_ref_exit();
 963         return -ENOMEM;
 964 }