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