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         }
 193         ref->in_tree = 0;
 194         btrfs_put_delayed_ref(ref);
 195         atomic_dec(&delayed_refs->num_entries);
 196 }
 197
 198 static bool merge_ref(struct btrfs_trans_handle *trans,
 199                       struct btrfs_delayed_ref_root *delayed_refs,
 200                       struct btrfs_delayed_ref_head *head,
 201                       struct btrfs_delayed_ref_node *ref,
 202                       u64 seq)
 203 {
 204         struct btrfs_delayed_ref_node *next;
 205         bool done = false;
 206
 207         next = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
 208                                 list);
 209         while (!done && &next->list != &head->ref_list) {
 210                 int mod;
 211                 struct btrfs_delayed_ref_node *next2;
 212
 213                 next2 = list_next_entry(next, list);
 214
 215                 if (next == ref)
 216                         goto next;
 217
 218                 if (seq && next->seq >= seq)
 219                         goto next;
 220
 221                 if (next->type != ref->type)
 222                         goto next;
 223
 224                 if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 225                      ref->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
 226                     comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref),
 227                                    btrfs_delayed_node_to_tree_ref(next),
 228                                    ref->type))
 229                         goto next;
 230                 if ((ref->type == BTRFS_EXTENT_DATA_REF_KEY ||
 231                      ref->type == BTRFS_SHARED_DATA_REF_KEY) &&
 232                     comp_data_refs(btrfs_delayed_node_to_data_ref(ref),
 233                                    btrfs_delayed_node_to_data_ref(next)))
 234                         goto next;
 235
 236                 if (ref->action == next->action) {
 237                         mod = next->ref_mod;
 238                 } else {
 239                         if (ref->ref_mod < next->ref_mod) {
 240                                 swap(ref, next);
 241                                 done = true;
 242                         }
 243                         mod = -next->ref_mod;
 244                 }
 245
 246                 drop_delayed_ref(trans, delayed_refs, head, next);
 247                 ref->ref_mod += mod;
 248                 if (ref->ref_mod == 0) {
 249                         drop_delayed_ref(trans, delayed_refs, head, ref);
 250                         done = true;
 251                 } else {
 252                         /*
 253                          * Can't have multiples of the same ref on a tree block.
 254                          */
 255                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 256                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 257                 }
 258 next:
 259                 next = next2;
 260         }
 261
 262         return done;
 263 }
 264
 265 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 266                               struct btrfs_fs_info *fs_info,
 267                               struct btrfs_delayed_ref_root *delayed_refs,
 268                               struct btrfs_delayed_ref_head *head)
 269 {
 270         struct btrfs_delayed_ref_node *ref;
 271         u64 seq = 0;
 272
 273         assert_spin_locked(&head->lock);
 274
 275         if (list_empty(&head->ref_list))
 276                 return;
 277
 278         /* We don't have too many refs to merge for data. */
 279         if (head->is_data)
 280                 return;
 281
 282         read_lock(&fs_info->tree_mod_log_lock);
 283         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 284                 struct seq_list *elem;
 285
 286                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 287                                         struct seq_list, list);
 288                 seq = elem->seq;
 289         }
 290         read_unlock(&fs_info->tree_mod_log_lock);
 291
 292         ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
 293                                list);
 294         while (&ref->list != &head->ref_list) {
 295                 if (seq && ref->seq >= seq)
 296                         goto next;
 297
 298                 if (merge_ref(trans, delayed_refs, head, ref, seq)) {
 299                         if (list_empty(&head->ref_list))
 300                                 break;
 301                         ref = list_first_entry(&head->ref_list,
 302                                                struct btrfs_delayed_ref_node,
 303                                                list);
 304                         continue;
 305                 }
 306 next:
 307                 ref = list_next_entry(ref, list);
 308         }
 309 }
 310
 311 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 312                             struct btrfs_delayed_ref_root *delayed_refs,
 313                             u64 seq)
 314 {
 315         struct seq_list *elem;
 316         int ret = 0;
 317
 318         read_lock(&fs_info->tree_mod_log_lock);
 319         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 320                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 321                                         struct seq_list, list);
 322                 if (seq >= elem->seq) {
 323                         pr_debug("holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)\n",
 324                                  (u32)(seq >> 32), (u32)seq,
 325                                  (u32)(elem->seq >> 32), (u32)elem->seq,
 326                                  delayed_refs);
 327                         ret = 1;
 328                 }
 329         }
 330
 331         read_unlock(&fs_info->tree_mod_log_lock);
 332         return ret;
 333 }
 334
 335 struct btrfs_delayed_ref_head *
 336 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 337 {
 338         struct btrfs_delayed_ref_root *delayed_refs;
 339         struct btrfs_delayed_ref_head *head;
 340         u64 start;
 341         bool loop = false;
 342
 343         delayed_refs = &trans->transaction->delayed_refs;
 344
 345 again:
 346         start = delayed_refs->run_delayed_start;
 347         head = find_ref_head(&delayed_refs->href_root, start, 1);
 348         if (!head && !loop) {
 349                 delayed_refs->run_delayed_start = 0;
 350                 start = 0;
 351                 loop = true;
 352                 head = find_ref_head(&delayed_refs->href_root, start, 1);
 353                 if (!head)
 354                         return NULL;
 355         } else if (!head && loop) {
 356                 return NULL;
 357         }
 358
 359         while (head->processing) {
 360                 struct rb_node *node;
 361
 362                 node = rb_next(&head->href_node);
 363                 if (!node) {
 364                         if (loop)
 365                                 return NULL;
 366                         delayed_refs->run_delayed_start = 0;
 367                         start = 0;
 368                         loop = true;
 369                         goto again;
 370                 }
 371                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 372                                 href_node);
 373         }
 374
 375         head->processing = 1;
 376         WARN_ON(delayed_refs->num_heads_ready == 0);
 377         delayed_refs->num_heads_ready--;
 378         delayed_refs->run_delayed_start = head->node.bytenr +
 379                 head->node.num_bytes;
 380         return head;
 381 }
 382
 383 /*
 384  * Helper to insert the ref_node to the tail or merge with tail.
 385  *
 386  * Return 0 for insert.
 387  * Return >0 for merge.
 388  */
 389 static int
 390 add_delayed_ref_tail_merge(struct btrfs_trans_handle *trans,
 391                            struct btrfs_delayed_ref_root *root,
 392                            struct btrfs_delayed_ref_head *href,
 393                            struct btrfs_delayed_ref_node *ref)
 394 {
 395         struct btrfs_delayed_ref_node *exist;
 396         int mod;
 397         int ret = 0;
 398
 399         spin_lock(&href->lock);
 400         /* Check whether we can merge the tail node with ref */
 401         if (list_empty(&href->ref_list))
 402                 goto add_tail;
 403         exist = list_entry(href->ref_list.prev, struct btrfs_delayed_ref_node,
 404                            list);
 405         /* No need to compare bytenr nor is_head */
 406         if (exist->type != ref->type || exist->seq != ref->seq)
 407                 goto add_tail;
 408
 409         if ((exist->type == BTRFS_TREE_BLOCK_REF_KEY ||
 410              exist->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
 411             comp_tree_refs(btrfs_delayed_node_to_tree_ref(exist),
 412                            btrfs_delayed_node_to_tree_ref(ref),
 413                            ref->type))
 414                 goto add_tail;
 415         if ((exist->type == BTRFS_EXTENT_DATA_REF_KEY ||
 416              exist->type == BTRFS_SHARED_DATA_REF_KEY) &&
 417             comp_data_refs(btrfs_delayed_node_to_data_ref(exist),
 418                            btrfs_delayed_node_to_data_ref(ref)))
 419                 goto add_tail;
 420
 421         /* Now we are sure we can merge */
 422         ret = 1;
 423         if (exist->action == ref->action) {
 424                 mod = ref->ref_mod;
 425         } else {
 426                 /* Need to change action */
 427                 if (exist->ref_mod < ref->ref_mod) {
 428                         exist->action = ref->action;
 429                         mod = -exist->ref_mod;
 430                         exist->ref_mod = ref->ref_mod;
 431                 } else
 432                         mod = -ref->ref_mod;
 433         }
 434         exist->ref_mod += mod;
 435
 436         /* remove existing tail if its ref_mod is zero */
 437         if (exist->ref_mod == 0)
 438                 drop_delayed_ref(trans, root, href, exist);
 439         spin_unlock(&href->lock);
 440         return ret;
 441
 442 add_tail:
 443         list_add_tail(&ref->list, &href->ref_list);
 444         atomic_inc(&root->num_entries);
 445         spin_unlock(&href->lock);
 446         return ret;
 447 }
 448
 449 /*
 450  * helper function to update the accounting in the head ref
 451  * existing and update must have the same bytenr
 452  */
 453 static noinline void
 454 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
 455                          struct btrfs_delayed_ref_node *existing,
 456                          struct btrfs_delayed_ref_node *update)
 457 {
 458         struct btrfs_delayed_ref_head *existing_ref;
 459         struct btrfs_delayed_ref_head *ref;
 460         int old_ref_mod;
 461
 462         existing_ref = btrfs_delayed_node_to_head(existing);
 463         ref = btrfs_delayed_node_to_head(update);
 464         BUG_ON(existing_ref->is_data != ref->is_data);
 465
 466         spin_lock(&existing_ref->lock);
 467         if (ref->must_insert_reserved) {
 468                 /* if the extent was freed and then
 469                  * reallocated before the delayed ref
 470                  * entries were processed, we can end up
 471                  * with an existing head ref without
 472                  * the must_insert_reserved flag set.
 473                  * Set it again here
 474                  */
 475                 existing_ref->must_insert_reserved = ref->must_insert_reserved;
 476
 477                 /*
 478                  * update the num_bytes so we make sure the accounting
 479                  * is done correctly
 480                  */
 481                 existing->num_bytes = update->num_bytes;
 482
 483         }
 484
 485         if (ref->extent_op) {
 486                 if (!existing_ref->extent_op) {
 487                         existing_ref->extent_op = ref->extent_op;
 488                 } else {
 489                         if (ref->extent_op->update_key) {
 490                                 memcpy(&existing_ref->extent_op->key,
 491                                        &ref->extent_op->key,
 492                                        sizeof(ref->extent_op->key));
 493                                 existing_ref->extent_op->update_key = 1;
 494                         }
 495                         if (ref->extent_op->update_flags) {
 496                                 existing_ref->extent_op->flags_to_set |=
 497                                         ref->extent_op->flags_to_set;
 498                                 existing_ref->extent_op->update_flags = 1;
 499                         }
 500                         btrfs_free_delayed_extent_op(ref->extent_op);
 501                 }
 502         }
 503         /*
 504          * update the reference mod on the head to reflect this new operation,
 505          * only need the lock for this case cause we could be processing it
 506          * currently, for refs we just added we know we're a-ok.
 507          */
 508         old_ref_mod = existing_ref->total_ref_mod;
 509         existing->ref_mod += update->ref_mod;
 510         existing_ref->total_ref_mod += update->ref_mod;
 511
 512         /*
 513          * If we are going to from a positive ref mod to a negative or vice
 514          * versa we need to make sure to adjust pending_csums accordingly.
 515          */
 516         if (existing_ref->is_data) {
 517                 if (existing_ref->total_ref_mod >= 0 && old_ref_mod < 0)
 518                         delayed_refs->pending_csums -= existing->num_bytes;
 519                 if (existing_ref->total_ref_mod < 0 && old_ref_mod >= 0)
 520                         delayed_refs->pending_csums += existing->num_bytes;
 521         }
 522         spin_unlock(&existing_ref->lock);
 523 }
 524
 525 /*
 526  * helper function to actually insert a head node into the rbtree.
 527  * this does all the dirty work in terms of maintaining the correct
 528  * overall modification count.
 529  */
 530 static noinline struct btrfs_delayed_ref_head *
 531 add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 532                      struct btrfs_trans_handle *trans,
 533                      struct btrfs_delayed_ref_node *ref,
 534                      struct btrfs_qgroup_extent_record *qrecord,
 535                      u64 bytenr, u64 num_bytes, u64 ref_root, u64 reserved,
 536                      int action, int is_data)
 537 {
 538         struct btrfs_delayed_ref_head *existing;
 539         struct btrfs_delayed_ref_head *head_ref = NULL;
 540         struct btrfs_delayed_ref_root *delayed_refs;
 541         struct btrfs_qgroup_extent_record *qexisting;
 542         int count_mod = 1;
 543         int must_insert_reserved = 0;
 544
 545         /* If reserved is provided, it must be a data extent. */
 546         BUG_ON(!is_data && reserved);
 547
 548         /*
 549          * the head node stores the sum of all the mods, so dropping a ref
 550          * should drop the sum in the head node by one.
 551          */
 552         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 553                 count_mod = 0;
 554         else if (action == BTRFS_DROP_DELAYED_REF)
 555                 count_mod = -1;
 556
 557         /*
 558          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 559          * the reserved accounting when the extent is finally added, or
 560          * if a later modification deletes the delayed ref without ever
 561          * inserting the extent into the extent allocation tree.
 562          * ref->must_insert_reserved is the flag used to record
 563          * that accounting mods are required.
 564          *
 565          * Once we record must_insert_reserved, switch the action to
 566          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 567          */
 568         if (action == BTRFS_ADD_DELAYED_EXTENT)
 569                 must_insert_reserved = 1;
 570         else
 571                 must_insert_reserved = 0;
 572
 573         delayed_refs = &trans->transaction->delayed_refs;
 574
 575         /* first set the basic ref node struct up */
 576         atomic_set(&ref->refs, 1);
 577         ref->bytenr = bytenr;
 578         ref->num_bytes = num_bytes;
 579         ref->ref_mod = count_mod;
 580         ref->type  = 0;
 581         ref->action  = 0;
 582         ref->is_head = 1;
 583         ref->in_tree = 1;
 584         ref->seq = 0;
 585
 586         head_ref = btrfs_delayed_node_to_head(ref);
 587         head_ref->must_insert_reserved = must_insert_reserved;
 588         head_ref->is_data = is_data;
 589         INIT_LIST_HEAD(&head_ref->ref_list);
 590         head_ref->processing = 0;
 591         head_ref->total_ref_mod = count_mod;
 592         head_ref->qgroup_reserved = 0;
 593         head_ref->qgroup_ref_root = 0;
 594
 595         /* Record qgroup extent info if provided */
 596         if (qrecord) {
 597                 if (ref_root && reserved) {
 598                         head_ref->qgroup_ref_root = ref_root;
 599                         head_ref->qgroup_reserved = reserved;
 600                 }
 601
 602                 qrecord->bytenr = bytenr;
 603                 qrecord->num_bytes = num_bytes;
 604                 qrecord->old_roots = NULL;
 605
 606                 qexisting = btrfs_qgroup_insert_dirty_extent(delayed_refs,
 607                                                              qrecord);
 608                 if (qexisting)
 609                         kfree(qrecord);
 610         }
 611
 612         spin_lock_init(&head_ref->lock);
 613         mutex_init(&head_ref->mutex);
 614
 615         trace_add_delayed_ref_head(ref, head_ref, action);
 616
 617         existing = htree_insert(&delayed_refs->href_root,
 618                                 &head_ref->href_node);
 619         if (existing) {
 620                 WARN_ON(ref_root && reserved && existing->qgroup_ref_root
 621                         && existing->qgroup_reserved);
 622                 update_existing_head_ref(delayed_refs, &existing->node, ref);
 623                 /*
 624                  * we've updated the existing ref, free the newly
 625                  * allocated ref
 626                  */
 627                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 628                 head_ref = existing;
 629         } else {
 630                 if (is_data && count_mod < 0)
 631                         delayed_refs->pending_csums += num_bytes;
 632                 delayed_refs->num_heads++;
 633                 delayed_refs->num_heads_ready++;
 634                 atomic_inc(&delayed_refs->num_entries);
 635                 trans->delayed_ref_updates++;
 636         }
 637         return head_ref;
 638 }
 639
 640 /*
 641  * helper to insert a delayed tree ref into the rbtree.
 642  */
 643 static noinline void
 644 add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 645                      struct btrfs_trans_handle *trans,
 646                      struct btrfs_delayed_ref_head *head_ref,
 647                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 648                      u64 num_bytes, u64 parent, u64 ref_root, int level,
 649                      int action)
 650 {
 651         struct btrfs_delayed_tree_ref *full_ref;
 652         struct btrfs_delayed_ref_root *delayed_refs;
 653         u64 seq = 0;
 654         int ret;
 655
 656         if (action == BTRFS_ADD_DELAYED_EXTENT)
 657                 action = BTRFS_ADD_DELAYED_REF;
 658
 659         if (is_fstree(ref_root))
 660                 seq = atomic64_read(&fs_info->tree_mod_seq);
 661         delayed_refs = &trans->transaction->delayed_refs;
 662
 663         /* first set the basic ref node struct up */
 664         atomic_set(&ref->refs, 1);
 665         ref->bytenr = bytenr;
 666         ref->num_bytes = num_bytes;
 667         ref->ref_mod = 1;
 668         ref->action = action;
 669         ref->is_head = 0;
 670         ref->in_tree = 1;
 671         ref->seq = seq;
 672
 673         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 674         full_ref->parent = parent;
 675         full_ref->root = ref_root;
 676         if (parent)
 677                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 678         else
 679                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 680         full_ref->level = level;
 681
 682         trace_add_delayed_tree_ref(ref, full_ref, action);
 683
 684         ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
 685
 686         /*
 687          * XXX: memory should be freed at the same level allocated.
 688          * But bad practice is anywhere... Follow it now. Need cleanup.
 689          */
 690         if (ret > 0)
 691                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 692 }
 693
 694 /*
 695  * helper to insert a delayed data ref into the rbtree.
 696  */
 697 static noinline void
 698 add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 699                      struct btrfs_trans_handle *trans,
 700                      struct btrfs_delayed_ref_head *head_ref,
 701                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 702                      u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
 703                      u64 offset, int action)
 704 {
 705         struct btrfs_delayed_data_ref *full_ref;
 706         struct btrfs_delayed_ref_root *delayed_refs;
 707         u64 seq = 0;
 708         int ret;
 709
 710         if (action == BTRFS_ADD_DELAYED_EXTENT)
 711                 action = BTRFS_ADD_DELAYED_REF;
 712
 713         delayed_refs = &trans->transaction->delayed_refs;
 714
 715         if (is_fstree(ref_root))
 716                 seq = atomic64_read(&fs_info->tree_mod_seq);
 717
 718         /* first set the basic ref node struct up */
 719         atomic_set(&ref->refs, 1);
 720         ref->bytenr = bytenr;
 721         ref->num_bytes = num_bytes;
 722         ref->ref_mod = 1;
 723         ref->action = action;
 724         ref->is_head = 0;
 725         ref->in_tree = 1;
 726         ref->seq = seq;
 727
 728         full_ref = btrfs_delayed_node_to_data_ref(ref);
 729         full_ref->parent = parent;
 730         full_ref->root = ref_root;
 731         if (parent)
 732                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 733         else
 734                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 735
 736         full_ref->objectid = owner;
 737         full_ref->offset = offset;
 738
 739         trace_add_delayed_data_ref(ref, full_ref, action);
 740
 741         ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
 742
 743         if (ret > 0)
 744                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 745 }
 746
 747 /*
 748  * add a delayed tree ref.  This does all of the accounting required
 749  * to make sure the delayed ref is eventually processed before this
 750  * transaction commits.
 751  */
 752 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 753                                struct btrfs_trans_handle *trans,
 754                                u64 bytenr, u64 num_bytes, u64 parent,
 755                                u64 ref_root,  int level, int action,
 756                                struct btrfs_delayed_extent_op *extent_op)
 757 {
 758         struct btrfs_delayed_tree_ref *ref;
 759         struct btrfs_delayed_ref_head *head_ref;
 760         struct btrfs_delayed_ref_root *delayed_refs;
 761         struct btrfs_qgroup_extent_record *record = NULL;
 762
 763         BUG_ON(extent_op && extent_op->is_data);
 764         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 765         if (!ref)
 766                 return -ENOMEM;
 767
 768         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 769         if (!head_ref)
 770                 goto free_ref;
 771
 772         if (fs_info->quota_enabled && is_fstree(ref_root)) {
 773                 record = kmalloc(sizeof(*record), GFP_NOFS);
 774                 if (!record)
 775                         goto free_head_ref;
 776         }
 777
 778         head_ref->extent_op = extent_op;
 779
 780         delayed_refs = &trans->transaction->delayed_refs;
 781         spin_lock(&delayed_refs->lock);
 782
 783         /*
 784          * insert both the head node and the new ref without dropping
 785          * the spin lock
 786          */
 787         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
 788                                         bytenr, num_bytes, 0, 0, action, 0);
 789
 790         add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 791                              num_bytes, parent, ref_root, level, action);
 792         spin_unlock(&delayed_refs->lock);
 793
 794         return 0;
 795
 796 free_head_ref:
 797         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 798 free_ref:
 799         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 800
 801         return -ENOMEM;
 802 }
 803
 804 /*
 805  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 806  */
 807 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 808                                struct btrfs_trans_handle *trans,
 809                                u64 bytenr, u64 num_bytes,
 810                                u64 parent, u64 ref_root,
 811                                u64 owner, u64 offset, u64 reserved, int action,
 812                                struct btrfs_delayed_extent_op *extent_op)
 813 {
 814         struct btrfs_delayed_data_ref *ref;
 815         struct btrfs_delayed_ref_head *head_ref;
 816         struct btrfs_delayed_ref_root *delayed_refs;
 817         struct btrfs_qgroup_extent_record *record = NULL;
 818
 819         BUG_ON(extent_op && !extent_op->is_data);
 820         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 821         if (!ref)
 822                 return -ENOMEM;
 823
 824         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 825         if (!head_ref) {
 826                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 827                 return -ENOMEM;
 828         }
 829
 830         if (fs_info->quota_enabled && is_fstree(ref_root)) {
 831                 record = kmalloc(sizeof(*record), GFP_NOFS);
 832                 if (!record) {
 833                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 834                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
 835                                         head_ref);
 836                         return -ENOMEM;
 837                 }
 838         }
 839
 840         head_ref->extent_op = extent_op;
 841
 842         delayed_refs = &trans->transaction->delayed_refs;
 843         spin_lock(&delayed_refs->lock);
 844
 845         /*
 846          * insert both the head node and the new ref without dropping
 847          * the spin lock
 848          */
 849         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
 850                                         bytenr, num_bytes, ref_root, reserved,
 851                                         action, 1);
 852
 853         add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 854                                    num_bytes, parent, ref_root, owner, offset,
 855                                    action);
 856         spin_unlock(&delayed_refs->lock);
 857
 858         return 0;
 859 }
 860
 861 int btrfs_add_delayed_qgroup_reserve(struct btrfs_fs_info *fs_info,
 862                                      struct btrfs_trans_handle *trans,
 863                                      u64 ref_root, u64 bytenr, u64 num_bytes)
 864 {
 865         struct btrfs_delayed_ref_root *delayed_refs;
 866         struct btrfs_delayed_ref_head *ref_head;
 867         int ret = 0;
 868
 869         if (!fs_info->quota_enabled || !is_fstree(ref_root))
 870                 return 0;
 871
 872         delayed_refs = &trans->transaction->delayed_refs;
 873
 874         spin_lock(&delayed_refs->lock);
 875         ref_head = find_ref_head(&delayed_refs->href_root, bytenr, 0);
 876         if (!ref_head) {
 877                 ret = -ENOENT;
 878                 goto out;
 879         }
 880         WARN_ON(ref_head->qgroup_reserved || ref_head->qgroup_ref_root);
 881         ref_head->qgroup_ref_root = ref_root;
 882         ref_head->qgroup_reserved = num_bytes;
 883 out:
 884         spin_unlock(&delayed_refs->lock);
 885         return ret;
 886 }
 887
 888 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 889                                 struct btrfs_trans_handle *trans,
 890                                 u64 bytenr, u64 num_bytes,
 891                                 struct btrfs_delayed_extent_op *extent_op)
 892 {
 893         struct btrfs_delayed_ref_head *head_ref;
 894         struct btrfs_delayed_ref_root *delayed_refs;
 895
 896         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 897         if (!head_ref)
 898                 return -ENOMEM;
 899
 900         head_ref->extent_op = extent_op;
 901
 902         delayed_refs = &trans->transaction->delayed_refs;
 903         spin_lock(&delayed_refs->lock);
 904
 905         add_delayed_ref_head(fs_info, trans, &head_ref->node, NULL, bytenr,
 906                              num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,
 907                              extent_op->is_data);
 908
 909         spin_unlock(&delayed_refs->lock);
 910         return 0;
 911 }
 912
 913 /*
 914  * this does a simple search for the head node for a given extent.
 915  * It must be called with the delayed ref spinlock held, and it returns
 916  * the head node if any where found, or NULL if not.
 917  */
 918 struct btrfs_delayed_ref_head *
 919 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
 920 {
 921         struct btrfs_delayed_ref_root *delayed_refs;
 922
 923         delayed_refs = &trans->transaction->delayed_refs;
 924         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
 925 }
 926
 927 void btrfs_delayed_ref_exit(void)
 928 {
 929         if (btrfs_delayed_ref_head_cachep)
 930                 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 931         if (btrfs_delayed_tree_ref_cachep)
 932                 kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 933         if (btrfs_delayed_data_ref_cachep)
 934                 kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 935         if (btrfs_delayed_extent_op_cachep)
 936                 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 937 }
 938
 939 int btrfs_delayed_ref_init(void)
 940 {
 941         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 942                                 "btrfs_delayed_ref_head",
 943                                 sizeof(struct btrfs_delayed_ref_head), 0,
 944                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 945         if (!btrfs_delayed_ref_head_cachep)
 946                 goto fail;
 947
 948         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 949                                 "btrfs_delayed_tree_ref",
 950                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 951                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 952         if (!btrfs_delayed_tree_ref_cachep)
 953                 goto fail;
 954
 955         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 956                                 "btrfs_delayed_data_ref",
 957                                 sizeof(struct btrfs_delayed_data_ref), 0,
 958                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 959         if (!btrfs_delayed_data_ref_cachep)
 960                 goto fail;
 961
 962         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 963                                 "btrfs_delayed_extent_op",
 964                                 sizeof(struct btrfs_delayed_extent_op), 0,
 965                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 966         if (!btrfs_delayed_extent_op_cachep)
 967                 goto fail;
 968
 969         return 0;
 970 fail:
 971         btrfs_delayed_ref_exit();
 972         return -ENOMEM;
 973 }