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 *ref1,
  44                           struct btrfs_delayed_tree_ref *ref2)
  45 {
  46         if (ref1->node.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 *ref1,
  64                           struct btrfs_delayed_data_ref *ref2)
  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 static int comp_refs(struct btrfs_delayed_ref_node *ref1,
  89                      struct btrfs_delayed_ref_node *ref2,
  90                      bool check_seq)
  91 {
  92         int ret = 0;
  93
  94         if (ref1->type < ref2->type)
  95                 return -1;
  96         if (ref1->type > ref2->type)
  97                 return 1;
  98         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
  99             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
 100                 ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
 101                                      btrfs_delayed_node_to_tree_ref(ref2));
 102         else
 103                 ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
 104                                      btrfs_delayed_node_to_data_ref(ref2));
 105         if (ret)
 106                 return ret;
 107         if (check_seq) {
 108                 if (ref1->seq < ref2->seq)
 109                         return -1;
 110                 if (ref1->seq > ref2->seq)
 111                         return 1;
 112         }
 113         return 0;
 114 }
 115
 116 /* insert a new ref to head ref rbtree */
 117 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
 118                                                    struct rb_node *node)
 119 {
 120         struct rb_node **p = &root->rb_node;
 121         struct rb_node *parent_node = NULL;
 122         struct btrfs_delayed_ref_head *entry;
 123         struct btrfs_delayed_ref_head *ins;
 124         u64 bytenr;
 125
 126         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
 127         bytenr = ins->bytenr;
 128         while (*p) {
 129                 parent_node = *p;
 130                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
 131                                  href_node);
 132
 133                 if (bytenr < entry->bytenr)
 134                         p = &(*p)->rb_left;
 135                 else if (bytenr > entry->bytenr)
 136                         p = &(*p)->rb_right;
 137                 else
 138                         return entry;
 139         }
 140
 141         rb_link_node(node, parent_node, p);
 142         rb_insert_color(node, root);
 143         return NULL;
 144 }
 145
 146 static struct btrfs_delayed_ref_node* tree_insert(struct rb_root *root,
 147                 struct btrfs_delayed_ref_node *ins)
 148 {
 149         struct rb_node **p = &root->rb_node;
 150         struct rb_node *node = &ins->ref_node;
 151         struct rb_node *parent_node = NULL;
 152         struct btrfs_delayed_ref_node *entry;
 153
 154         while (*p) {
 155                 int comp;
 156
 157                 parent_node = *p;
 158                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
 159                                  ref_node);
 160                 comp = comp_refs(ins, entry, true);
 161                 if (comp < 0)
 162                         p = &(*p)->rb_left;
 163                 else if (comp > 0)
 164                         p = &(*p)->rb_right;
 165                 else
 166                         return entry;
 167         }
 168
 169         rb_link_node(node, parent_node, p);
 170         rb_insert_color(node, root);
 171         return NULL;
 172 }
 173
 174 /*
 175  * find an head entry based on bytenr. This returns the delayed ref
 176  * head if it was able to find one, or NULL if nothing was in that spot.
 177  * If return_bigger is given, the next bigger entry is returned if no exact
 178  * match is found.
 179  */
 180 static struct btrfs_delayed_ref_head *
 181 find_ref_head(struct rb_root *root, u64 bytenr,
 182               int return_bigger)
 183 {
 184         struct rb_node *n;
 185         struct btrfs_delayed_ref_head *entry;
 186
 187         n = root->rb_node;
 188         entry = NULL;
 189         while (n) {
 190                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
 191
 192                 if (bytenr < entry->bytenr)
 193                         n = n->rb_left;
 194                 else if (bytenr > entry->bytenr)
 195                         n = n->rb_right;
 196                 else
 197                         return entry;
 198         }
 199         if (entry && return_bigger) {
 200                 if (bytenr > entry->bytenr) {
 201                         n = rb_next(&entry->href_node);
 202                         if (!n)
 203                                 n = rb_first(root);
 204                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
 205                                          href_node);
 206                         return entry;
 207                 }
 208                 return entry;
 209         }
 210         return NULL;
 211 }
 212
 213 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 214                            struct btrfs_delayed_ref_head *head)
 215 {
 216         struct btrfs_delayed_ref_root *delayed_refs;
 217
 218         delayed_refs = &trans->transaction->delayed_refs;
 219         assert_spin_locked(&delayed_refs->lock);
 220         if (mutex_trylock(&head->mutex))
 221                 return 0;
 222
 223         refcount_inc(&head->refs);
 224         spin_unlock(&delayed_refs->lock);
 225
 226         mutex_lock(&head->mutex);
 227         spin_lock(&delayed_refs->lock);
 228         if (RB_EMPTY_NODE(&head->href_node)) {
 229                 mutex_unlock(&head->mutex);
 230                 btrfs_put_delayed_ref_head(head);
 231                 return -EAGAIN;
 232         }
 233         btrfs_put_delayed_ref_head(head);
 234         return 0;
 235 }
 236
 237 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 238                                     struct btrfs_delayed_ref_root *delayed_refs,
 239                                     struct btrfs_delayed_ref_head *head,
 240                                     struct btrfs_delayed_ref_node *ref)
 241 {
 242         assert_spin_locked(&head->lock);
 243         rb_erase(&ref->ref_node, &head->ref_tree);
 244         RB_CLEAR_NODE(&ref->ref_node);
 245         if (!list_empty(&ref->add_list))
 246                 list_del(&ref->add_list);
 247         ref->in_tree = 0;
 248         btrfs_put_delayed_ref(ref);
 249         atomic_dec(&delayed_refs->num_entries);
 250         if (trans->delayed_ref_updates)
 251                 trans->delayed_ref_updates--;
 252 }
 253
 254 static bool merge_ref(struct btrfs_trans_handle *trans,
 255                       struct btrfs_delayed_ref_root *delayed_refs,
 256                       struct btrfs_delayed_ref_head *head,
 257                       struct btrfs_delayed_ref_node *ref,
 258                       u64 seq)
 259 {
 260         struct btrfs_delayed_ref_node *next;
 261         struct rb_node *node = rb_next(&ref->ref_node);
 262         bool done = false;
 263
 264         while (!done && node) {
 265                 int mod;
 266
 267                 next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
 268                 node = rb_next(node);
 269                 if (seq && next->seq >= seq)
 270                         break;
 271                 if (comp_refs(ref, next, false))
 272                         break;
 273
 274                 if (ref->action == next->action) {
 275                         mod = next->ref_mod;
 276                 } else {
 277                         if (ref->ref_mod < next->ref_mod) {
 278                                 swap(ref, next);
 279                                 done = true;
 280                         }
 281                         mod = -next->ref_mod;
 282                 }
 283
 284                 drop_delayed_ref(trans, delayed_refs, head, next);
 285                 ref->ref_mod += mod;
 286                 if (ref->ref_mod == 0) {
 287                         drop_delayed_ref(trans, delayed_refs, head, ref);
 288                         done = true;
 289                 } else {
 290                         /*
 291                          * Can't have multiples of the same ref on a tree block.
 292                          */
 293                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 294                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 295                 }
 296         }
 297
 298         return done;
 299 }
 300
 301 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 302                               struct btrfs_fs_info *fs_info,
 303                               struct btrfs_delayed_ref_root *delayed_refs,
 304                               struct btrfs_delayed_ref_head *head)
 305 {
 306         struct btrfs_delayed_ref_node *ref;
 307         struct rb_node *node;
 308         u64 seq = 0;
 309
 310         assert_spin_locked(&head->lock);
 311
 312         if (RB_EMPTY_ROOT(&head->ref_tree))
 313                 return;
 314
 315         /* We don't have too many refs to merge for data. */
 316         if (head->is_data)
 317                 return;
 318
 319         spin_lock(&fs_info->tree_mod_seq_lock);
 320         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 321                 struct seq_list *elem;
 322
 323                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 324                                         struct seq_list, list);
 325                 seq = elem->seq;
 326         }
 327         spin_unlock(&fs_info->tree_mod_seq_lock);
 328
 329 again:
 330         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
 331                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
 332                 if (seq && ref->seq >= seq)
 333                         continue;
 334                 if (merge_ref(trans, delayed_refs, head, ref, seq))
 335                         goto again;
 336         }
 337 }
 338
 339 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 340                             struct btrfs_delayed_ref_root *delayed_refs,
 341                             u64 seq)
 342 {
 343         struct seq_list *elem;
 344         int ret = 0;
 345
 346         spin_lock(&fs_info->tree_mod_seq_lock);
 347         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 348                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 349                                         struct seq_list, list);
 350                 if (seq >= elem->seq) {
 351                         btrfs_debug(fs_info,
 352                                 "holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)",
 353                                 (u32)(seq >> 32), (u32)seq,
 354                                 (u32)(elem->seq >> 32), (u32)elem->seq,
 355                                 delayed_refs);
 356                         ret = 1;
 357                 }
 358         }
 359
 360         spin_unlock(&fs_info->tree_mod_seq_lock);
 361         return ret;
 362 }
 363
 364 struct btrfs_delayed_ref_head *
 365 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 366 {
 367         struct btrfs_delayed_ref_root *delayed_refs;
 368         struct btrfs_delayed_ref_head *head;
 369         u64 start;
 370         bool loop = false;
 371
 372         delayed_refs = &trans->transaction->delayed_refs;
 373
 374 again:
 375         start = delayed_refs->run_delayed_start;
 376         head = find_ref_head(&delayed_refs->href_root, start, 1);
 377         if (!head && !loop) {
 378                 delayed_refs->run_delayed_start = 0;
 379                 start = 0;
 380                 loop = true;
 381                 head = find_ref_head(&delayed_refs->href_root, start, 1);
 382                 if (!head)
 383                         return NULL;
 384         } else if (!head && loop) {
 385                 return NULL;
 386         }
 387
 388         while (head->processing) {
 389                 struct rb_node *node;
 390
 391                 node = rb_next(&head->href_node);
 392                 if (!node) {
 393                         if (loop)
 394                                 return NULL;
 395                         delayed_refs->run_delayed_start = 0;
 396                         start = 0;
 397                         loop = true;
 398                         goto again;
 399                 }
 400                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 401                                 href_node);
 402         }
 403
 404         head->processing = 1;
 405         WARN_ON(delayed_refs->num_heads_ready == 0);
 406         delayed_refs->num_heads_ready--;
 407         delayed_refs->run_delayed_start = head->bytenr +
 408                 head->num_bytes;
 409         return head;
 410 }
 411
 412 /*
 413  * Helper to insert the ref_node to the tail or merge with tail.
 414  *
 415  * Return 0 for insert.
 416  * Return >0 for merge.
 417  */
 418 static int insert_delayed_ref(struct btrfs_trans_handle *trans,
 419                               struct btrfs_delayed_ref_root *root,
 420                               struct btrfs_delayed_ref_head *href,
 421                               struct btrfs_delayed_ref_node *ref)
 422 {
 423         struct btrfs_delayed_ref_node *exist;
 424         int mod;
 425         int ret = 0;
 426
 427         spin_lock(&href->lock);
 428         exist = tree_insert(&href->ref_tree, ref);
 429         if (!exist)
 430                 goto inserted;
 431
 432         /* Now we are sure we can merge */
 433         ret = 1;
 434         if (exist->action == ref->action) {
 435                 mod = ref->ref_mod;
 436         } else {
 437                 /* Need to change action */
 438                 if (exist->ref_mod < ref->ref_mod) {
 439                         exist->action = ref->action;
 440                         mod = -exist->ref_mod;
 441                         exist->ref_mod = ref->ref_mod;
 442                         if (ref->action == BTRFS_ADD_DELAYED_REF)
 443                                 list_add_tail(&exist->add_list,
 444                                               &href->ref_add_list);
 445                         else if (ref->action == BTRFS_DROP_DELAYED_REF) {
 446                                 ASSERT(!list_empty(&exist->add_list));
 447                                 list_del(&exist->add_list);
 448                         } else {
 449                                 ASSERT(0);
 450                         }
 451                 } else
 452                         mod = -ref->ref_mod;
 453         }
 454         exist->ref_mod += mod;
 455
 456         /* remove existing tail if its ref_mod is zero */
 457         if (exist->ref_mod == 0)
 458                 drop_delayed_ref(trans, root, href, exist);
 459         spin_unlock(&href->lock);
 460         return ret;
 461 inserted:
 462         if (ref->action == BTRFS_ADD_DELAYED_REF)
 463                 list_add_tail(&ref->add_list, &href->ref_add_list);
 464         atomic_inc(&root->num_entries);
 465         trans->delayed_ref_updates++;
 466         spin_unlock(&href->lock);
 467         return ret;
 468 }
 469
 470 /*
 471  * helper function to update the accounting in the head ref
 472  * existing and update must have the same bytenr
 473  */
 474 static noinline void
 475 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
 476                          struct btrfs_delayed_ref_head *existing,
 477                          struct btrfs_delayed_ref_head *update,
 478                          int *old_ref_mod_ret)
 479 {
 480         int old_ref_mod;
 481
 482         BUG_ON(existing->is_data != update->is_data);
 483
 484         spin_lock(&existing->lock);
 485         if (update->must_insert_reserved) {
 486                 /* if the extent was freed and then
 487                  * reallocated before the delayed ref
 488                  * entries were processed, we can end up
 489                  * with an existing head ref without
 490                  * the must_insert_reserved flag set.
 491                  * Set it again here
 492                  */
 493                 existing->must_insert_reserved = update->must_insert_reserved;
 494
 495                 /*
 496                  * update the num_bytes so we make sure the accounting
 497                  * is done correctly
 498                  */
 499                 existing->num_bytes = update->num_bytes;
 500
 501         }
 502
 503         if (update->extent_op) {
 504                 if (!existing->extent_op) {
 505                         existing->extent_op = update->extent_op;
 506                 } else {
 507                         if (update->extent_op->update_key) {
 508                                 memcpy(&existing->extent_op->key,
 509                                        &update->extent_op->key,
 510                                        sizeof(update->extent_op->key));
 511                                 existing->extent_op->update_key = true;
 512                         }
 513                         if (update->extent_op->update_flags) {
 514                                 existing->extent_op->flags_to_set |=
 515                                         update->extent_op->flags_to_set;
 516                                 existing->extent_op->update_flags = true;
 517                         }
 518                         btrfs_free_delayed_extent_op(update->extent_op);
 519                 }
 520         }
 521         /*
 522          * update the reference mod on the head to reflect this new operation,
 523          * only need the lock for this case cause we could be processing it
 524          * currently, for refs we just added we know we're a-ok.
 525          */
 526         old_ref_mod = existing->total_ref_mod;
 527         if (old_ref_mod_ret)
 528                 *old_ref_mod_ret = old_ref_mod;
 529         existing->ref_mod += update->ref_mod;
 530         existing->total_ref_mod += update->ref_mod;
 531
 532         /*
 533          * If we are going to from a positive ref mod to a negative or vice
 534          * versa we need to make sure to adjust pending_csums accordingly.
 535          */
 536         if (existing->is_data) {
 537                 if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
 538                         delayed_refs->pending_csums -= existing->num_bytes;
 539                 if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
 540                         delayed_refs->pending_csums += existing->num_bytes;
 541         }
 542         spin_unlock(&existing->lock);
 543 }
 544
 545 /*
 546  * helper function to actually insert a head node into the rbtree.
 547  * this does all the dirty work in terms of maintaining the correct
 548  * overall modification count.
 549  */
 550 static noinline struct btrfs_delayed_ref_head *
 551 add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 552                      struct btrfs_trans_handle *trans,
 553                      struct btrfs_delayed_ref_head *head_ref,
 554                      struct btrfs_qgroup_extent_record *qrecord,
 555                      u64 bytenr, u64 num_bytes, u64 ref_root, u64 reserved,
 556                      int action, int is_data, int *qrecord_inserted_ret,
 557                      int *old_ref_mod, int *new_ref_mod)
 558 {
 559         struct btrfs_delayed_ref_head *existing;
 560         struct btrfs_delayed_ref_root *delayed_refs;
 561         int count_mod = 1;
 562         int must_insert_reserved = 0;
 563         int qrecord_inserted = 0;
 564
 565         /* If reserved is provided, it must be a data extent. */
 566         BUG_ON(!is_data && reserved);
 567
 568         /*
 569          * the head node stores the sum of all the mods, so dropping a ref
 570          * should drop the sum in the head node by one.
 571          */
 572         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 573                 count_mod = 0;
 574         else if (action == BTRFS_DROP_DELAYED_REF)
 575                 count_mod = -1;
 576
 577         /*
 578          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 579          * the reserved accounting when the extent is finally added, or
 580          * if a later modification deletes the delayed ref without ever
 581          * inserting the extent into the extent allocation tree.
 582          * ref->must_insert_reserved is the flag used to record
 583          * that accounting mods are required.
 584          *
 585          * Once we record must_insert_reserved, switch the action to
 586          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 587          */
 588         if (action == BTRFS_ADD_DELAYED_EXTENT)
 589                 must_insert_reserved = 1;
 590         else
 591                 must_insert_reserved = 0;
 592
 593         delayed_refs = &trans->transaction->delayed_refs;
 594
 595         refcount_set(&head_ref->refs, 1);
 596         head_ref->bytenr = bytenr;
 597         head_ref->num_bytes = num_bytes;
 598         head_ref->ref_mod = count_mod;
 599         head_ref->must_insert_reserved = must_insert_reserved;
 600         head_ref->is_data = is_data;
 601         head_ref->ref_tree = RB_ROOT;
 602         INIT_LIST_HEAD(&head_ref->ref_add_list);
 603         RB_CLEAR_NODE(&head_ref->href_node);
 604         head_ref->processing = 0;
 605         head_ref->total_ref_mod = count_mod;
 606         head_ref->qgroup_reserved = 0;
 607         head_ref->qgroup_ref_root = 0;
 608         spin_lock_init(&head_ref->lock);
 609         mutex_init(&head_ref->mutex);
 610
 611         /* Record qgroup extent info if provided */
 612         if (qrecord) {
 613                 if (ref_root && reserved) {
 614                         head_ref->qgroup_ref_root = ref_root;
 615                         head_ref->qgroup_reserved = reserved;
 616                 }
 617
 618                 qrecord->bytenr = bytenr;
 619                 qrecord->num_bytes = num_bytes;
 620                 qrecord->old_roots = NULL;
 621
 622                 if(btrfs_qgroup_trace_extent_nolock(fs_info,
 623                                         delayed_refs, qrecord))
 624                         kfree(qrecord);
 625                 else
 626                         qrecord_inserted = 1;
 627         }
 628
 629         trace_add_delayed_ref_head(fs_info, head_ref, action);
 630
 631         existing = htree_insert(&delayed_refs->href_root,
 632                                 &head_ref->href_node);
 633         if (existing) {
 634                 WARN_ON(ref_root && reserved && existing->qgroup_ref_root
 635                         && existing->qgroup_reserved);
 636                 update_existing_head_ref(delayed_refs, existing, head_ref,
 637                                          old_ref_mod);
 638                 /*
 639                  * we've updated the existing ref, free the newly
 640                  * allocated ref
 641                  */
 642                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 643                 head_ref = existing;
 644         } else {
 645                 if (old_ref_mod)
 646                         *old_ref_mod = 0;
 647                 if (is_data && count_mod < 0)
 648                         delayed_refs->pending_csums += num_bytes;
 649                 delayed_refs->num_heads++;
 650                 delayed_refs->num_heads_ready++;
 651                 atomic_inc(&delayed_refs->num_entries);
 652                 trans->delayed_ref_updates++;
 653         }
 654         if (qrecord_inserted_ret)
 655                 *qrecord_inserted_ret = qrecord_inserted;
 656         if (new_ref_mod)
 657                 *new_ref_mod = head_ref->total_ref_mod;
 658         return head_ref;
 659 }
 660
 661 /*
 662  * helper to insert a delayed tree ref into the rbtree.
 663  */
 664 static noinline void
 665 add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 666                      struct btrfs_trans_handle *trans,
 667                      struct btrfs_delayed_ref_head *head_ref,
 668                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 669                      u64 num_bytes, u64 parent, u64 ref_root, int level,
 670                      int action)
 671 {
 672         struct btrfs_delayed_tree_ref *full_ref;
 673         struct btrfs_delayed_ref_root *delayed_refs;
 674         u64 seq = 0;
 675         int ret;
 676
 677         if (action == BTRFS_ADD_DELAYED_EXTENT)
 678                 action = BTRFS_ADD_DELAYED_REF;
 679
 680         if (is_fstree(ref_root))
 681                 seq = atomic64_read(&fs_info->tree_mod_seq);
 682         delayed_refs = &trans->transaction->delayed_refs;
 683
 684         /* first set the basic ref node struct up */
 685         refcount_set(&ref->refs, 1);
 686         ref->bytenr = bytenr;
 687         ref->num_bytes = num_bytes;
 688         ref->ref_mod = 1;
 689         ref->action = action;
 690         ref->is_head = 0;
 691         ref->in_tree = 1;
 692         ref->seq = seq;
 693         RB_CLEAR_NODE(&ref->ref_node);
 694         INIT_LIST_HEAD(&ref->add_list);
 695
 696         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 697         full_ref->parent = parent;
 698         full_ref->root = ref_root;
 699         if (parent)
 700                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 701         else
 702                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 703         full_ref->level = level;
 704
 705         trace_add_delayed_tree_ref(fs_info, ref, full_ref, action);
 706
 707         ret = insert_delayed_ref(trans, delayed_refs, head_ref, ref);
 708
 709         /*
 710          * XXX: memory should be freed at the same level allocated.
 711          * But bad practice is anywhere... Follow it now. Need cleanup.
 712          */
 713         if (ret > 0)
 714                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 715 }
 716
 717 /*
 718  * helper to insert a delayed data ref into the rbtree.
 719  */
 720 static noinline void
 721 add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 722                      struct btrfs_trans_handle *trans,
 723                      struct btrfs_delayed_ref_head *head_ref,
 724                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 725                      u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
 726                      u64 offset, int action)
 727 {
 728         struct btrfs_delayed_data_ref *full_ref;
 729         struct btrfs_delayed_ref_root *delayed_refs;
 730         u64 seq = 0;
 731         int ret;
 732
 733         if (action == BTRFS_ADD_DELAYED_EXTENT)
 734                 action = BTRFS_ADD_DELAYED_REF;
 735
 736         delayed_refs = &trans->transaction->delayed_refs;
 737
 738         if (is_fstree(ref_root))
 739                 seq = atomic64_read(&fs_info->tree_mod_seq);
 740
 741         /* first set the basic ref node struct up */
 742         refcount_set(&ref->refs, 1);
 743         ref->bytenr = bytenr;
 744         ref->num_bytes = num_bytes;
 745         ref->ref_mod = 1;
 746         ref->action = action;
 747         ref->is_head = 0;
 748         ref->in_tree = 1;
 749         ref->seq = seq;
 750         RB_CLEAR_NODE(&ref->ref_node);
 751         INIT_LIST_HEAD(&ref->add_list);
 752
 753         full_ref = btrfs_delayed_node_to_data_ref(ref);
 754         full_ref->parent = parent;
 755         full_ref->root = ref_root;
 756         if (parent)
 757                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 758         else
 759                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 760
 761         full_ref->objectid = owner;
 762         full_ref->offset = offset;
 763
 764         trace_add_delayed_data_ref(fs_info, ref, full_ref, action);
 765
 766         ret = insert_delayed_ref(trans, delayed_refs, head_ref, ref);
 767         if (ret > 0)
 768                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 769 }
 770
 771 /*
 772  * add a delayed tree ref.  This does all of the accounting required
 773  * to make sure the delayed ref is eventually processed before this
 774  * transaction commits.
 775  */
 776 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 777                                struct btrfs_trans_handle *trans,
 778                                u64 bytenr, u64 num_bytes, u64 parent,
 779                                u64 ref_root,  int level, int action,
 780                                struct btrfs_delayed_extent_op *extent_op,
 781                                int *old_ref_mod, int *new_ref_mod)
 782 {
 783         struct btrfs_delayed_tree_ref *ref;
 784         struct btrfs_delayed_ref_head *head_ref;
 785         struct btrfs_delayed_ref_root *delayed_refs;
 786         struct btrfs_qgroup_extent_record *record = NULL;
 787         int qrecord_inserted;
 788
 789         BUG_ON(extent_op && extent_op->is_data);
 790         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 791         if (!ref)
 792                 return -ENOMEM;
 793
 794         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 795         if (!head_ref)
 796                 goto free_ref;
 797
 798         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 799             is_fstree(ref_root)) {
 800                 record = kmalloc(sizeof(*record), GFP_NOFS);
 801                 if (!record)
 802                         goto free_head_ref;
 803         }
 804
 805         head_ref->extent_op = extent_op;
 806
 807         delayed_refs = &trans->transaction->delayed_refs;
 808         spin_lock(&delayed_refs->lock);
 809
 810         /*
 811          * insert both the head node and the new ref without dropping
 812          * the spin lock
 813          */
 814         head_ref = add_delayed_ref_head(fs_info, trans, head_ref, record,
 815                                         bytenr, num_bytes, 0, 0, action, 0,
 816                                         &qrecord_inserted, old_ref_mod,
 817                                         new_ref_mod);
 818
 819         add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 820                              num_bytes, parent, ref_root, level, action);
 821         spin_unlock(&delayed_refs->lock);
 822
 823         if (qrecord_inserted)
 824                 btrfs_qgroup_trace_extent_post(fs_info, record);
 825
 826         return 0;
 827
 828 free_head_ref:
 829         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 830 free_ref:
 831         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 832
 833         return -ENOMEM;
 834 }
 835
 836 /*
 837  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 838  */
 839 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 840                                struct btrfs_trans_handle *trans,
 841                                u64 bytenr, u64 num_bytes,
 842                                u64 parent, u64 ref_root,
 843                                u64 owner, u64 offset, u64 reserved, int action,
 844                                int *old_ref_mod, int *new_ref_mod)
 845 {
 846         struct btrfs_delayed_data_ref *ref;
 847         struct btrfs_delayed_ref_head *head_ref;
 848         struct btrfs_delayed_ref_root *delayed_refs;
 849         struct btrfs_qgroup_extent_record *record = NULL;
 850         int qrecord_inserted;
 851
 852         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 853         if (!ref)
 854                 return -ENOMEM;
 855
 856         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 857         if (!head_ref) {
 858                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 859                 return -ENOMEM;
 860         }
 861
 862         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 863             is_fstree(ref_root)) {
 864                 record = kmalloc(sizeof(*record), GFP_NOFS);
 865                 if (!record) {
 866                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 867                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
 868                                         head_ref);
 869                         return -ENOMEM;
 870                 }
 871         }
 872
 873         head_ref->extent_op = NULL;
 874
 875         delayed_refs = &trans->transaction->delayed_refs;
 876         spin_lock(&delayed_refs->lock);
 877
 878         /*
 879          * insert both the head node and the new ref without dropping
 880          * the spin lock
 881          */
 882         head_ref = add_delayed_ref_head(fs_info, trans, head_ref, record,
 883                                         bytenr, num_bytes, ref_root, reserved,
 884                                         action, 1, &qrecord_inserted,
 885                                         old_ref_mod, new_ref_mod);
 886
 887         add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 888                                    num_bytes, parent, ref_root, owner, offset,
 889                                    action);
 890         spin_unlock(&delayed_refs->lock);
 891
 892         if (qrecord_inserted)
 893                 return btrfs_qgroup_trace_extent_post(fs_info, record);
 894         return 0;
 895 }
 896
 897 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 898                                 struct btrfs_trans_handle *trans,
 899                                 u64 bytenr, u64 num_bytes,
 900                                 struct btrfs_delayed_extent_op *extent_op)
 901 {
 902         struct btrfs_delayed_ref_head *head_ref;
 903         struct btrfs_delayed_ref_root *delayed_refs;
 904
 905         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 906         if (!head_ref)
 907                 return -ENOMEM;
 908
 909         head_ref->extent_op = extent_op;
 910
 911         delayed_refs = &trans->transaction->delayed_refs;
 912         spin_lock(&delayed_refs->lock);
 913
 914         add_delayed_ref_head(fs_info, trans, head_ref, NULL, bytenr,
 915                              num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,
 916                              extent_op->is_data, NULL, NULL, NULL);
 917
 918         spin_unlock(&delayed_refs->lock);
 919         return 0;
 920 }
 921
 922 /*
 923  * this does a simple search for the head node for a given extent.
 924  * It must be called with the delayed ref spinlock held, and it returns
 925  * the head node if any where found, or NULL if not.
 926  */
 927 struct btrfs_delayed_ref_head *
 928 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
 929 {
 930         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
 931 }
 932
 933 void btrfs_delayed_ref_exit(void)
 934 {
 935         kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 936         kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 937         kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 938         kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 939 }
 940
 941 int __init btrfs_delayed_ref_init(void)
 942 {
 943         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 944                                 "btrfs_delayed_ref_head",
 945                                 sizeof(struct btrfs_delayed_ref_head), 0,
 946                                 SLAB_MEM_SPREAD, NULL);
 947         if (!btrfs_delayed_ref_head_cachep)
 948                 goto fail;
 949
 950         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 951                                 "btrfs_delayed_tree_ref",
 952                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 953                                 SLAB_MEM_SPREAD, NULL);
 954         if (!btrfs_delayed_tree_ref_cachep)
 955                 goto fail;
 956
 957         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 958                                 "btrfs_delayed_data_ref",
 959                                 sizeof(struct btrfs_delayed_data_ref), 0,
 960                                 SLAB_MEM_SPREAD, NULL);
 961         if (!btrfs_delayed_data_ref_cachep)
 962                 goto fail;
 963
 964         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 965                                 "btrfs_delayed_extent_op",
 966                                 sizeof(struct btrfs_delayed_extent_op), 0,
 967                                 SLAB_MEM_SPREAD, NULL);
 968         if (!btrfs_delayed_extent_op_cachep)
 969                 goto fail;
 970
 971         return 0;
 972 fail:
 973         btrfs_delayed_ref_exit();
 974         return -ENOMEM;
 975 }