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         refcount_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 }
 199
 200 static bool merge_ref(struct btrfs_trans_handle *trans,
 201                       struct btrfs_delayed_ref_root *delayed_refs,
 202                       struct btrfs_delayed_ref_head *head,
 203                       struct btrfs_delayed_ref_node *ref,
 204                       u64 seq)
 205 {
 206         struct btrfs_delayed_ref_node *next;
 207         bool done = false;
 208
 209         next = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
 210                                 list);
 211         while (!done && &next->list != &head->ref_list) {
 212                 int mod;
 213                 struct btrfs_delayed_ref_node *next2;
 214
 215                 next2 = list_next_entry(next, list);
 216
 217                 if (next == ref)
 218                         goto next;
 219
 220                 if (seq && next->seq >= seq)
 221                         goto next;
 222
 223                 if (next->type != ref->type)
 224                         goto next;
 225
 226                 if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 227                      ref->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
 228                     comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref),
 229                                    btrfs_delayed_node_to_tree_ref(next),
 230                                    ref->type))
 231                         goto next;
 232                 if ((ref->type == BTRFS_EXTENT_DATA_REF_KEY ||
 233                      ref->type == BTRFS_SHARED_DATA_REF_KEY) &&
 234                     comp_data_refs(btrfs_delayed_node_to_data_ref(ref),
 235                                    btrfs_delayed_node_to_data_ref(next)))
 236                         goto next;
 237
 238                 if (ref->action == next->action) {
 239                         mod = next->ref_mod;
 240                 } else {
 241                         if (ref->ref_mod < next->ref_mod) {
 242                                 swap(ref, next);
 243                                 done = true;
 244                         }
 245                         mod = -next->ref_mod;
 246                 }
 247
 248                 drop_delayed_ref(trans, delayed_refs, head, next);
 249                 ref->ref_mod += mod;
 250                 if (ref->ref_mod == 0) {
 251                         drop_delayed_ref(trans, delayed_refs, head, ref);
 252                         done = true;
 253                 } else {
 254                         /*
 255                          * Can't have multiples of the same ref on a tree block.
 256                          */
 257                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 258                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 259                 }
 260 next:
 261                 next = next2;
 262         }
 263
 264         return done;
 265 }
 266
 267 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 268                               struct btrfs_fs_info *fs_info,
 269                               struct btrfs_delayed_ref_root *delayed_refs,
 270                               struct btrfs_delayed_ref_head *head)
 271 {
 272         struct btrfs_delayed_ref_node *ref;
 273         u64 seq = 0;
 274
 275         assert_spin_locked(&head->lock);
 276
 277         if (list_empty(&head->ref_list))
 278                 return;
 279
 280         /* We don't have too many refs to merge for data. */
 281         if (head->is_data)
 282                 return;
 283
 284         read_lock(&fs_info->tree_mod_log_lock);
 285         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 286                 struct seq_list *elem;
 287
 288                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 289                                         struct seq_list, list);
 290                 seq = elem->seq;
 291         }
 292         read_unlock(&fs_info->tree_mod_log_lock);
 293
 294         ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
 295                                list);
 296         while (&ref->list != &head->ref_list) {
 297                 if (seq && ref->seq >= seq)
 298                         goto next;
 299
 300                 if (merge_ref(trans, delayed_refs, head, ref, seq)) {
 301                         if (list_empty(&head->ref_list))
 302                                 break;
 303                         ref = list_first_entry(&head->ref_list,
 304                                                struct btrfs_delayed_ref_node,
 305                                                list);
 306                         continue;
 307                 }
 308 next:
 309                 ref = list_next_entry(ref, list);
 310         }
 311 }
 312
 313 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 314                             struct btrfs_delayed_ref_root *delayed_refs,
 315                             u64 seq)
 316 {
 317         struct seq_list *elem;
 318         int ret = 0;
 319
 320         read_lock(&fs_info->tree_mod_log_lock);
 321         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 322                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 323                                         struct seq_list, list);
 324                 if (seq >= elem->seq) {
 325                         btrfs_debug(fs_info,
 326                                 "holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)",
 327                                 (u32)(seq >> 32), (u32)seq,
 328                                 (u32)(elem->seq >> 32), (u32)elem->seq,
 329                                 delayed_refs);
 330                         ret = 1;
 331                 }
 332         }
 333
 334         read_unlock(&fs_info->tree_mod_log_lock);
 335         return ret;
 336 }
 337
 338 struct btrfs_delayed_ref_head *
 339 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 340 {
 341         struct btrfs_delayed_ref_root *delayed_refs;
 342         struct btrfs_delayed_ref_head *head;
 343         u64 start;
 344         bool loop = false;
 345
 346         delayed_refs = &trans->transaction->delayed_refs;
 347
 348 again:
 349         start = delayed_refs->run_delayed_start;
 350         head = find_ref_head(&delayed_refs->href_root, start, 1);
 351         if (!head && !loop) {
 352                 delayed_refs->run_delayed_start = 0;
 353                 start = 0;
 354                 loop = true;
 355                 head = find_ref_head(&delayed_refs->href_root, start, 1);
 356                 if (!head)
 357                         return NULL;
 358         } else if (!head && loop) {
 359                 return NULL;
 360         }
 361
 362         while (head->processing) {
 363                 struct rb_node *node;
 364
 365                 node = rb_next(&head->href_node);
 366                 if (!node) {
 367                         if (loop)
 368                                 return NULL;
 369                         delayed_refs->run_delayed_start = 0;
 370                         start = 0;
 371                         loop = true;
 372                         goto again;
 373                 }
 374                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 375                                 href_node);
 376         }
 377
 378         head->processing = 1;
 379         WARN_ON(delayed_refs->num_heads_ready == 0);
 380         delayed_refs->num_heads_ready--;
 381         delayed_refs->run_delayed_start = head->node.bytenr +
 382                 head->node.num_bytes;
 383         return head;
 384 }
 385
 386 /*
 387  * Helper to insert the ref_node to the tail or merge with tail.
 388  *
 389  * Return 0 for insert.
 390  * Return >0 for merge.
 391  */
 392 static int
 393 add_delayed_ref_tail_merge(struct btrfs_trans_handle *trans,
 394                            struct btrfs_delayed_ref_root *root,
 395                            struct btrfs_delayed_ref_head *href,
 396                            struct btrfs_delayed_ref_node *ref)
 397 {
 398         struct btrfs_delayed_ref_node *exist;
 399         int mod;
 400         int ret = 0;
 401
 402         spin_lock(&href->lock);
 403         /* Check whether we can merge the tail node with ref */
 404         if (list_empty(&href->ref_list))
 405                 goto add_tail;
 406         exist = list_entry(href->ref_list.prev, struct btrfs_delayed_ref_node,
 407                            list);
 408         /* No need to compare bytenr nor is_head */
 409         if (exist->type != ref->type || exist->seq != ref->seq)
 410                 goto add_tail;
 411
 412         if ((exist->type == BTRFS_TREE_BLOCK_REF_KEY ||
 413              exist->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
 414             comp_tree_refs(btrfs_delayed_node_to_tree_ref(exist),
 415                            btrfs_delayed_node_to_tree_ref(ref),
 416                            ref->type))
 417                 goto add_tail;
 418         if ((exist->type == BTRFS_EXTENT_DATA_REF_KEY ||
 419              exist->type == BTRFS_SHARED_DATA_REF_KEY) &&
 420             comp_data_refs(btrfs_delayed_node_to_data_ref(exist),
 421                            btrfs_delayed_node_to_data_ref(ref)))
 422                 goto add_tail;
 423
 424         /* Now we are sure we can merge */
 425         ret = 1;
 426         if (exist->action == ref->action) {
 427                 mod = ref->ref_mod;
 428         } else {
 429                 /* Need to change action */
 430                 if (exist->ref_mod < ref->ref_mod) {
 431                         exist->action = ref->action;
 432                         mod = -exist->ref_mod;
 433                         exist->ref_mod = ref->ref_mod;
 434                         if (ref->action == BTRFS_ADD_DELAYED_REF)
 435                                 list_add_tail(&exist->add_list,
 436                                               &href->ref_add_list);
 437                         else if (ref->action == BTRFS_DROP_DELAYED_REF) {
 438                                 ASSERT(!list_empty(&exist->add_list));
 439                                 list_del(&exist->add_list);
 440                         } else {
 441                                 ASSERT(0);
 442                         }
 443                 } else
 444                         mod = -ref->ref_mod;
 445         }
 446         exist->ref_mod += mod;
 447
 448         /* remove existing tail if its ref_mod is zero */
 449         if (exist->ref_mod == 0)
 450                 drop_delayed_ref(trans, root, href, exist);
 451         spin_unlock(&href->lock);
 452         return ret;
 453
 454 add_tail:
 455         list_add_tail(&ref->list, &href->ref_list);
 456         if (ref->action == BTRFS_ADD_DELAYED_REF)
 457                 list_add_tail(&ref->add_list, &href->ref_add_list);
 458         atomic_inc(&root->num_entries);
 459         spin_unlock(&href->lock);
 460         return ret;
 461 }
 462
 463 /*
 464  * helper function to update the accounting in the head ref
 465  * existing and update must have the same bytenr
 466  */
 467 static noinline void
 468 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
 469                          struct btrfs_delayed_ref_node *existing,
 470                          struct btrfs_delayed_ref_node *update,
 471                          int *old_ref_mod_ret)
 472 {
 473         struct btrfs_delayed_ref_head *existing_ref;
 474         struct btrfs_delayed_ref_head *ref;
 475         int old_ref_mod;
 476
 477         existing_ref = btrfs_delayed_node_to_head(existing);
 478         ref = btrfs_delayed_node_to_head(update);
 479         BUG_ON(existing_ref->is_data != ref->is_data);
 480
 481         spin_lock(&existing_ref->lock);
 482         if (ref->must_insert_reserved) {
 483                 /* if the extent was freed and then
 484                  * reallocated before the delayed ref
 485                  * entries were processed, we can end up
 486                  * with an existing head ref without
 487                  * the must_insert_reserved flag set.
 488                  * Set it again here
 489                  */
 490                 existing_ref->must_insert_reserved = ref->must_insert_reserved;
 491
 492                 /*
 493                  * update the num_bytes so we make sure the accounting
 494                  * is done correctly
 495                  */
 496                 existing->num_bytes = update->num_bytes;
 497
 498         }
 499
 500         if (ref->extent_op) {
 501                 if (!existing_ref->extent_op) {
 502                         existing_ref->extent_op = ref->extent_op;
 503                 } else {
 504                         if (ref->extent_op->update_key) {
 505                                 memcpy(&existing_ref->extent_op->key,
 506                                        &ref->extent_op->key,
 507                                        sizeof(ref->extent_op->key));
 508                                 existing_ref->extent_op->update_key = true;
 509                         }
 510                         if (ref->extent_op->update_flags) {
 511                                 existing_ref->extent_op->flags_to_set |=
 512                                         ref->extent_op->flags_to_set;
 513                                 existing_ref->extent_op->update_flags = true;
 514                         }
 515                         btrfs_free_delayed_extent_op(ref->extent_op);
 516                 }
 517         }
 518         /*
 519          * update the reference mod on the head to reflect this new operation,
 520          * only need the lock for this case cause we could be processing it
 521          * currently, for refs we just added we know we're a-ok.
 522          */
 523         old_ref_mod = existing_ref->total_ref_mod;
 524         if (old_ref_mod_ret)
 525                 *old_ref_mod_ret = old_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, int *qrecord_inserted_ret,
 554                      int *old_ref_mod, int *new_ref_mod)
 555 {
 556         struct btrfs_delayed_ref_head *existing;
 557         struct btrfs_delayed_ref_head *head_ref = NULL;
 558         struct btrfs_delayed_ref_root *delayed_refs;
 559         int count_mod = 1;
 560         int must_insert_reserved = 0;
 561         int qrecord_inserted = 0;
 562
 563         /* If reserved is provided, it must be a data extent. */
 564         BUG_ON(!is_data && reserved);
 565
 566         /*
 567          * the head node stores the sum of all the mods, so dropping a ref
 568          * should drop the sum in the head node by one.
 569          */
 570         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 571                 count_mod = 0;
 572         else if (action == BTRFS_DROP_DELAYED_REF)
 573                 count_mod = -1;
 574
 575         /*
 576          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 577          * the reserved accounting when the extent is finally added, or
 578          * if a later modification deletes the delayed ref without ever
 579          * inserting the extent into the extent allocation tree.
 580          * ref->must_insert_reserved is the flag used to record
 581          * that accounting mods are required.
 582          *
 583          * Once we record must_insert_reserved, switch the action to
 584          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 585          */
 586         if (action == BTRFS_ADD_DELAYED_EXTENT)
 587                 must_insert_reserved = 1;
 588         else
 589                 must_insert_reserved = 0;
 590
 591         delayed_refs = &trans->transaction->delayed_refs;
 592
 593         /* first set the basic ref node struct up */
 594         refcount_set(&ref->refs, 1);
 595         ref->bytenr = bytenr;
 596         ref->num_bytes = num_bytes;
 597         ref->ref_mod = count_mod;
 598         ref->type  = 0;
 599         ref->action  = 0;
 600         ref->is_head = 1;
 601         ref->in_tree = 1;
 602         ref->seq = 0;
 603
 604         head_ref = btrfs_delayed_node_to_head(ref);
 605         head_ref->must_insert_reserved = must_insert_reserved;
 606         head_ref->is_data = is_data;
 607         INIT_LIST_HEAD(&head_ref->ref_list);
 608         INIT_LIST_HEAD(&head_ref->ref_add_list);
 609         head_ref->processing = 0;
 610         head_ref->total_ref_mod = count_mod;
 611         head_ref->qgroup_reserved = 0;
 612         head_ref->qgroup_ref_root = 0;
 613
 614         /* Record qgroup extent info if provided */
 615         if (qrecord) {
 616                 if (ref_root && reserved) {
 617                         head_ref->qgroup_ref_root = ref_root;
 618                         head_ref->qgroup_reserved = reserved;
 619                 }
 620
 621                 qrecord->bytenr = bytenr;
 622                 qrecord->num_bytes = num_bytes;
 623                 qrecord->old_roots = NULL;
 624
 625                 if(btrfs_qgroup_trace_extent_nolock(fs_info,
 626                                         delayed_refs, qrecord))
 627                         kfree(qrecord);
 628                 else
 629                         qrecord_inserted = 1;
 630         }
 631
 632         spin_lock_init(&head_ref->lock);
 633         mutex_init(&head_ref->mutex);
 634
 635         trace_add_delayed_ref_head(fs_info, ref, head_ref, action);
 636
 637         existing = htree_insert(&delayed_refs->href_root,
 638                                 &head_ref->href_node);
 639         if (existing) {
 640                 WARN_ON(ref_root && reserved && existing->qgroup_ref_root
 641                         && existing->qgroup_reserved);
 642                 update_existing_head_ref(delayed_refs, &existing->node, ref,
 643                                          old_ref_mod);
 644                 /*
 645                  * we've updated the existing ref, free the newly
 646                  * allocated ref
 647                  */
 648                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 649                 head_ref = existing;
 650         } else {
 651                 if (old_ref_mod)
 652                         *old_ref_mod = 0;
 653                 if (is_data && count_mod < 0)
 654                         delayed_refs->pending_csums += num_bytes;
 655                 delayed_refs->num_heads++;
 656                 delayed_refs->num_heads_ready++;
 657                 atomic_inc(&delayed_refs->num_entries);
 658                 trans->delayed_ref_updates++;
 659         }
 660         if (qrecord_inserted_ret)
 661                 *qrecord_inserted_ret = qrecord_inserted;
 662         if (new_ref_mod)
 663                 *new_ref_mod = head_ref->total_ref_mod;
 664         return head_ref;
 665 }
 666
 667 /*
 668  * helper to insert a delayed tree ref into the rbtree.
 669  */
 670 static noinline void
 671 add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 672                      struct btrfs_trans_handle *trans,
 673                      struct btrfs_delayed_ref_head *head_ref,
 674                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 675                      u64 num_bytes, u64 parent, u64 ref_root, int level,
 676                      int action)
 677 {
 678         struct btrfs_delayed_tree_ref *full_ref;
 679         struct btrfs_delayed_ref_root *delayed_refs;
 680         u64 seq = 0;
 681         int ret;
 682
 683         if (action == BTRFS_ADD_DELAYED_EXTENT)
 684                 action = BTRFS_ADD_DELAYED_REF;
 685
 686         if (is_fstree(ref_root))
 687                 seq = atomic64_read(&fs_info->tree_mod_seq);
 688         delayed_refs = &trans->transaction->delayed_refs;
 689
 690         /* first set the basic ref node struct up */
 691         refcount_set(&ref->refs, 1);
 692         ref->bytenr = bytenr;
 693         ref->num_bytes = num_bytes;
 694         ref->ref_mod = 1;
 695         ref->action = action;
 696         ref->is_head = 0;
 697         ref->in_tree = 1;
 698         ref->seq = seq;
 699         INIT_LIST_HEAD(&ref->list);
 700         INIT_LIST_HEAD(&ref->add_list);
 701
 702         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 703         full_ref->parent = parent;
 704         full_ref->root = ref_root;
 705         if (parent)
 706                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 707         else
 708                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 709         full_ref->level = level;
 710
 711         trace_add_delayed_tree_ref(fs_info, ref, full_ref, action);
 712
 713         ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
 714
 715         /*
 716          * XXX: memory should be freed at the same level allocated.
 717          * But bad practice is anywhere... Follow it now. Need cleanup.
 718          */
 719         if (ret > 0)
 720                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 721 }
 722
 723 /*
 724  * helper to insert a delayed data ref into the rbtree.
 725  */
 726 static noinline void
 727 add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 728                      struct btrfs_trans_handle *trans,
 729                      struct btrfs_delayed_ref_head *head_ref,
 730                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 731                      u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
 732                      u64 offset, int action)
 733 {
 734         struct btrfs_delayed_data_ref *full_ref;
 735         struct btrfs_delayed_ref_root *delayed_refs;
 736         u64 seq = 0;
 737         int ret;
 738
 739         if (action == BTRFS_ADD_DELAYED_EXTENT)
 740                 action = BTRFS_ADD_DELAYED_REF;
 741
 742         delayed_refs = &trans->transaction->delayed_refs;
 743
 744         if (is_fstree(ref_root))
 745                 seq = atomic64_read(&fs_info->tree_mod_seq);
 746
 747         /* first set the basic ref node struct up */
 748         refcount_set(&ref->refs, 1);
 749         ref->bytenr = bytenr;
 750         ref->num_bytes = num_bytes;
 751         ref->ref_mod = 1;
 752         ref->action = action;
 753         ref->is_head = 0;
 754         ref->in_tree = 1;
 755         ref->seq = seq;
 756         INIT_LIST_HEAD(&ref->list);
 757         INIT_LIST_HEAD(&ref->add_list);
 758
 759         full_ref = btrfs_delayed_node_to_data_ref(ref);
 760         full_ref->parent = parent;
 761         full_ref->root = ref_root;
 762         if (parent)
 763                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 764         else
 765                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 766
 767         full_ref->objectid = owner;
 768         full_ref->offset = offset;
 769
 770         trace_add_delayed_data_ref(fs_info, ref, full_ref, action);
 771
 772         ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
 773
 774         if (ret > 0)
 775                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 776 }
 777
 778 /*
 779  * add a delayed tree ref.  This does all of the accounting required
 780  * to make sure the delayed ref is eventually processed before this
 781  * transaction commits.
 782  */
 783 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 784                                struct btrfs_trans_handle *trans,
 785                                u64 bytenr, u64 num_bytes, u64 parent,
 786                                u64 ref_root,  int level, int action,
 787                                struct btrfs_delayed_extent_op *extent_op,
 788                                int *old_ref_mod, int *new_ref_mod)
 789 {
 790         struct btrfs_delayed_tree_ref *ref;
 791         struct btrfs_delayed_ref_head *head_ref;
 792         struct btrfs_delayed_ref_root *delayed_refs;
 793         struct btrfs_qgroup_extent_record *record = NULL;
 794         int qrecord_inserted;
 795
 796         BUG_ON(extent_op && extent_op->is_data);
 797         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 798         if (!ref)
 799                 return -ENOMEM;
 800
 801         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 802         if (!head_ref)
 803                 goto free_ref;
 804
 805         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 806             is_fstree(ref_root)) {
 807                 record = kmalloc(sizeof(*record), GFP_NOFS);
 808                 if (!record)
 809                         goto free_head_ref;
 810         }
 811
 812         head_ref->extent_op = extent_op;
 813
 814         delayed_refs = &trans->transaction->delayed_refs;
 815         spin_lock(&delayed_refs->lock);
 816
 817         /*
 818          * insert both the head node and the new ref without dropping
 819          * the spin lock
 820          */
 821         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
 822                                         bytenr, num_bytes, 0, 0, action, 0,
 823                                         &qrecord_inserted, old_ref_mod,
 824                                         new_ref_mod);
 825
 826         add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 827                              num_bytes, parent, ref_root, level, action);
 828         spin_unlock(&delayed_refs->lock);
 829
 830         if (qrecord_inserted)
 831                 return btrfs_qgroup_trace_extent_post(fs_info, record);
 832         return 0;
 833
 834 free_head_ref:
 835         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 836 free_ref:
 837         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 838
 839         return -ENOMEM;
 840 }
 841
 842 /*
 843  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 844  */
 845 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 846                                struct btrfs_trans_handle *trans,
 847                                u64 bytenr, u64 num_bytes,
 848                                u64 parent, u64 ref_root,
 849                                u64 owner, u64 offset, u64 reserved, int action,
 850                                int *old_ref_mod, int *new_ref_mod)
 851 {
 852         struct btrfs_delayed_data_ref *ref;
 853         struct btrfs_delayed_ref_head *head_ref;
 854         struct btrfs_delayed_ref_root *delayed_refs;
 855         struct btrfs_qgroup_extent_record *record = NULL;
 856         int qrecord_inserted;
 857
 858         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 859         if (!ref)
 860                 return -ENOMEM;
 861
 862         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 863         if (!head_ref) {
 864                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 865                 return -ENOMEM;
 866         }
 867
 868         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 869             is_fstree(ref_root)) {
 870                 record = kmalloc(sizeof(*record), GFP_NOFS);
 871                 if (!record) {
 872                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 873                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
 874                                         head_ref);
 875                         return -ENOMEM;
 876                 }
 877         }
 878
 879         head_ref->extent_op = NULL;
 880
 881         delayed_refs = &trans->transaction->delayed_refs;
 882         spin_lock(&delayed_refs->lock);
 883
 884         /*
 885          * insert both the head node and the new ref without dropping
 886          * the spin lock
 887          */
 888         head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
 889                                         bytenr, num_bytes, ref_root, reserved,
 890                                         action, 1, &qrecord_inserted,
 891                                         old_ref_mod, new_ref_mod);
 892
 893         add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 894                                    num_bytes, parent, ref_root, owner, offset,
 895                                    action);
 896         spin_unlock(&delayed_refs->lock);
 897
 898         if (qrecord_inserted)
 899                 return btrfs_qgroup_trace_extent_post(fs_info, record);
 900         return 0;
 901 }
 902
 903 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 904                                 struct btrfs_trans_handle *trans,
 905                                 u64 bytenr, u64 num_bytes,
 906                                 struct btrfs_delayed_extent_op *extent_op)
 907 {
 908         struct btrfs_delayed_ref_head *head_ref;
 909         struct btrfs_delayed_ref_root *delayed_refs;
 910
 911         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 912         if (!head_ref)
 913                 return -ENOMEM;
 914
 915         head_ref->extent_op = extent_op;
 916
 917         delayed_refs = &trans->transaction->delayed_refs;
 918         spin_lock(&delayed_refs->lock);
 919
 920         add_delayed_ref_head(fs_info, trans, &head_ref->node, NULL, bytenr,
 921                              num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,
 922                              extent_op->is_data, NULL, NULL, NULL);
 923
 924         spin_unlock(&delayed_refs->lock);
 925         return 0;
 926 }
 927
 928 /*
 929  * this does a simple search for the head node for a given extent.
 930  * It must be called with the delayed ref spinlock held, and it returns
 931  * the head node if any where found, or NULL if not.
 932  */
 933 struct btrfs_delayed_ref_head *
 934 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
 935 {
 936         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
 937 }
 938
 939 void btrfs_delayed_ref_exit(void)
 940 {
 941         kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 942         kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 943         kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 944         kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 945 }
 946
 947 int btrfs_delayed_ref_init(void)
 948 {
 949         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 950                                 "btrfs_delayed_ref_head",
 951                                 sizeof(struct btrfs_delayed_ref_head), 0,
 952                                 SLAB_MEM_SPREAD, NULL);
 953         if (!btrfs_delayed_ref_head_cachep)
 954                 goto fail;
 955
 956         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 957                                 "btrfs_delayed_tree_ref",
 958                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 959                                 SLAB_MEM_SPREAD, NULL);
 960         if (!btrfs_delayed_tree_ref_cachep)
 961                 goto fail;
 962
 963         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 964                                 "btrfs_delayed_data_ref",
 965                                 sizeof(struct btrfs_delayed_data_ref), 0,
 966                                 SLAB_MEM_SPREAD, NULL);
 967         if (!btrfs_delayed_data_ref_cachep)
 968                 goto fail;
 969
 970         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 971                                 "btrfs_delayed_extent_op",
 972                                 sizeof(struct btrfs_delayed_extent_op), 0,
 973                                 SLAB_MEM_SPREAD, NULL);
 974         if (!btrfs_delayed_extent_op_cachep)
 975                 goto fail;
 976
 977         return 0;
 978 fail:
 979         btrfs_delayed_ref_exit();
 980         return -ENOMEM;
 981 }