fs/btrfs/delayed-ref.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2009 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/slab.h>
   8 #include <linux/sort.h>
   9 #include "ctree.h"
  10 #include "delayed-ref.h"
  11 #include "transaction.h"
  12 #include "qgroup.h"
  13
  14 struct kmem_cache *btrfs_delayed_ref_head_cachep;
  15 struct kmem_cache *btrfs_delayed_tree_ref_cachep;
  16 struct kmem_cache *btrfs_delayed_data_ref_cachep;
  17 struct kmem_cache *btrfs_delayed_extent_op_cachep;
  18 /*
  19  * delayed back reference update tracking.  For subvolume trees
  20  * we queue up extent allocations and backref maintenance for
  21  * delayed processing.   This avoids deep call chains where we
  22  * add extents in the middle of btrfs_search_slot, and it allows
  23  * us to buffer up frequently modified backrefs in an rb tree instead
  24  * of hammering updates on the extent allocation tree.
  25  */
  26
  27 /*
  28  * compare two delayed tree backrefs with same bytenr and type
  29  */
  30 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1,
  31                           struct btrfs_delayed_tree_ref *ref2)
  32 {
  33         if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
  34                 if (ref1->root < ref2->root)
  35                         return -1;
  36                 if (ref1->root > ref2->root)
  37                         return 1;
  38         } else {
  39                 if (ref1->parent < ref2->parent)
  40                         return -1;
  41                 if (ref1->parent > ref2->parent)
  42                         return 1;
  43         }
  44         return 0;
  45 }
  46
  47 /*
  48  * compare two delayed data backrefs with same bytenr and type
  49  */
  50 static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
  51                           struct btrfs_delayed_data_ref *ref2)
  52 {
  53         if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
  54                 if (ref1->root < ref2->root)
  55                         return -1;
  56                 if (ref1->root > ref2->root)
  57                         return 1;
  58                 if (ref1->objectid < ref2->objectid)
  59                         return -1;
  60                 if (ref1->objectid > ref2->objectid)
  61                         return 1;
  62                 if (ref1->offset < ref2->offset)
  63                         return -1;
  64                 if (ref1->offset > ref2->offset)
  65                         return 1;
  66         } else {
  67                 if (ref1->parent < ref2->parent)
  68                         return -1;
  69                 if (ref1->parent > ref2->parent)
  70                         return 1;
  71         }
  72         return 0;
  73 }
  74
  75 static int comp_refs(struct btrfs_delayed_ref_node *ref1,
  76                      struct btrfs_delayed_ref_node *ref2,
  77                      bool check_seq)
  78 {
  79         int ret = 0;
  80
  81         if (ref1->type < ref2->type)
  82                 return -1;
  83         if (ref1->type > ref2->type)
  84                 return 1;
  85         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
  86             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
  87                 ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
  88                                      btrfs_delayed_node_to_tree_ref(ref2));
  89         else
  90                 ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
  91                                      btrfs_delayed_node_to_data_ref(ref2));
  92         if (ret)
  93                 return ret;
  94         if (check_seq) {
  95                 if (ref1->seq < ref2->seq)
  96                         return -1;
  97                 if (ref1->seq > ref2->seq)
  98                         return 1;
  99         }
 100         return 0;
 101 }
 102
 103 /* insert a new ref to head ref rbtree */
 104 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
 105                                                    struct rb_node *node)
 106 {
 107         struct rb_node **p = &root->rb_node;
 108         struct rb_node *parent_node = NULL;
 109         struct btrfs_delayed_ref_head *entry;
 110         struct btrfs_delayed_ref_head *ins;
 111         u64 bytenr;
 112
 113         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
 114         bytenr = ins->bytenr;
 115         while (*p) {
 116                 parent_node = *p;
 117                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
 118                                  href_node);
 119
 120                 if (bytenr < entry->bytenr)
 121                         p = &(*p)->rb_left;
 122                 else if (bytenr > entry->bytenr)
 123                         p = &(*p)->rb_right;
 124                 else
 125                         return entry;
 126         }
 127
 128         rb_link_node(node, parent_node, p);
 129         rb_insert_color(node, root);
 130         return NULL;
 131 }
 132
 133 static struct btrfs_delayed_ref_node* tree_insert(struct rb_root *root,
 134                 struct btrfs_delayed_ref_node *ins)
 135 {
 136         struct rb_node **p = &root->rb_node;
 137         struct rb_node *node = &ins->ref_node;
 138         struct rb_node *parent_node = NULL;
 139         struct btrfs_delayed_ref_node *entry;
 140
 141         while (*p) {
 142                 int comp;
 143
 144                 parent_node = *p;
 145                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
 146                                  ref_node);
 147                 comp = comp_refs(ins, entry, true);
 148                 if (comp < 0)
 149                         p = &(*p)->rb_left;
 150                 else if (comp > 0)
 151                         p = &(*p)->rb_right;
 152                 else
 153                         return entry;
 154         }
 155
 156         rb_link_node(node, parent_node, p);
 157         rb_insert_color(node, root);
 158         return NULL;
 159 }
 160
 161 /*
 162  * find an head entry based on bytenr. This returns the delayed ref
 163  * head if it was able to find one, or NULL if nothing was in that spot.
 164  * If return_bigger is given, the next bigger entry is returned if no exact
 165  * match is found.
 166  */
 167 static struct btrfs_delayed_ref_head *
 168 find_ref_head(struct rb_root *root, u64 bytenr,
 169               int return_bigger)
 170 {
 171         struct rb_node *n;
 172         struct btrfs_delayed_ref_head *entry;
 173
 174         n = root->rb_node;
 175         entry = NULL;
 176         while (n) {
 177                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
 178
 179                 if (bytenr < entry->bytenr)
 180                         n = n->rb_left;
 181                 else if (bytenr > entry->bytenr)
 182                         n = n->rb_right;
 183                 else
 184                         return entry;
 185         }
 186         if (entry && return_bigger) {
 187                 if (bytenr > entry->bytenr) {
 188                         n = rb_next(&entry->href_node);
 189                         if (!n)
 190                                 n = rb_first(root);
 191                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
 192                                          href_node);
 193                         return entry;
 194                 }
 195                 return entry;
 196         }
 197         return NULL;
 198 }
 199
 200 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 201                            struct btrfs_delayed_ref_head *head)
 202 {
 203         struct btrfs_delayed_ref_root *delayed_refs;
 204
 205         delayed_refs = &trans->transaction->delayed_refs;
 206         lockdep_assert_held(&delayed_refs->lock);
 207         if (mutex_trylock(&head->mutex))
 208                 return 0;
 209
 210         refcount_inc(&head->refs);
 211         spin_unlock(&delayed_refs->lock);
 212
 213         mutex_lock(&head->mutex);
 214         spin_lock(&delayed_refs->lock);
 215         if (RB_EMPTY_NODE(&head->href_node)) {
 216                 mutex_unlock(&head->mutex);
 217                 btrfs_put_delayed_ref_head(head);
 218                 return -EAGAIN;
 219         }
 220         btrfs_put_delayed_ref_head(head);
 221         return 0;
 222 }
 223
 224 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 225                                     struct btrfs_delayed_ref_root *delayed_refs,
 226                                     struct btrfs_delayed_ref_head *head,
 227                                     struct btrfs_delayed_ref_node *ref)
 228 {
 229         lockdep_assert_held(&head->lock);
 230         rb_erase(&ref->ref_node, &head->ref_tree);
 231         RB_CLEAR_NODE(&ref->ref_node);
 232         if (!list_empty(&ref->add_list))
 233                 list_del(&ref->add_list);
 234         ref->in_tree = 0;
 235         btrfs_put_delayed_ref(ref);
 236         atomic_dec(&delayed_refs->num_entries);
 237         if (trans->delayed_ref_updates)
 238                 trans->delayed_ref_updates--;
 239 }
 240
 241 static bool merge_ref(struct btrfs_trans_handle *trans,
 242                       struct btrfs_delayed_ref_root *delayed_refs,
 243                       struct btrfs_delayed_ref_head *head,
 244                       struct btrfs_delayed_ref_node *ref,
 245                       u64 seq)
 246 {
 247         struct btrfs_delayed_ref_node *next;
 248         struct rb_node *node = rb_next(&ref->ref_node);
 249         bool done = false;
 250
 251         while (!done && node) {
 252                 int mod;
 253
 254                 next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
 255                 node = rb_next(node);
 256                 if (seq && next->seq >= seq)
 257                         break;
 258                 if (comp_refs(ref, next, false))
 259                         break;
 260
 261                 if (ref->action == next->action) {
 262                         mod = next->ref_mod;
 263                 } else {
 264                         if (ref->ref_mod < next->ref_mod) {
 265                                 swap(ref, next);
 266                                 done = true;
 267                         }
 268                         mod = -next->ref_mod;
 269                 }
 270
 271                 drop_delayed_ref(trans, delayed_refs, head, next);
 272                 ref->ref_mod += mod;
 273                 if (ref->ref_mod == 0) {
 274                         drop_delayed_ref(trans, delayed_refs, head, ref);
 275                         done = true;
 276                 } else {
 277                         /*
 278                          * Can't have multiples of the same ref on a tree block.
 279                          */
 280                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 281                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 282                 }
 283         }
 284
 285         return done;
 286 }
 287
 288 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 289                               struct btrfs_fs_info *fs_info,
 290                               struct btrfs_delayed_ref_root *delayed_refs,
 291                               struct btrfs_delayed_ref_head *head)
 292 {
 293         struct btrfs_delayed_ref_node *ref;
 294         struct rb_node *node;
 295         u64 seq = 0;
 296
 297         lockdep_assert_held(&head->lock);
 298
 299         if (RB_EMPTY_ROOT(&head->ref_tree))
 300                 return;
 301
 302         /* We don't have too many refs to merge for data. */
 303         if (head->is_data)
 304                 return;
 305
 306         spin_lock(&fs_info->tree_mod_seq_lock);
 307         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 308                 struct seq_list *elem;
 309
 310                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 311                                         struct seq_list, list);
 312                 seq = elem->seq;
 313         }
 314         spin_unlock(&fs_info->tree_mod_seq_lock);
 315
 316 again:
 317         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
 318                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
 319                 if (seq && ref->seq >= seq)
 320                         continue;
 321                 if (merge_ref(trans, delayed_refs, head, ref, seq))
 322                         goto again;
 323         }
 324 }
 325
 326 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 327                             struct btrfs_delayed_ref_root *delayed_refs,
 328                             u64 seq)
 329 {
 330         struct seq_list *elem;
 331         int ret = 0;
 332
 333         spin_lock(&fs_info->tree_mod_seq_lock);
 334         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 335                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 336                                         struct seq_list, list);
 337                 if (seq >= elem->seq) {
 338                         btrfs_debug(fs_info,
 339                                 "holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)",
 340                                 (u32)(seq >> 32), (u32)seq,
 341                                 (u32)(elem->seq >> 32), (u32)elem->seq,
 342                                 delayed_refs);
 343                         ret = 1;
 344                 }
 345         }
 346
 347         spin_unlock(&fs_info->tree_mod_seq_lock);
 348         return ret;
 349 }
 350
 351 struct btrfs_delayed_ref_head *
 352 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
 353 {
 354         struct btrfs_delayed_ref_root *delayed_refs;
 355         struct btrfs_delayed_ref_head *head;
 356         u64 start;
 357         bool loop = false;
 358
 359         delayed_refs = &trans->transaction->delayed_refs;
 360
 361 again:
 362         start = delayed_refs->run_delayed_start;
 363         head = find_ref_head(&delayed_refs->href_root, start, 1);
 364         if (!head && !loop) {
 365                 delayed_refs->run_delayed_start = 0;
 366                 start = 0;
 367                 loop = true;
 368                 head = find_ref_head(&delayed_refs->href_root, start, 1);
 369                 if (!head)
 370                         return NULL;
 371         } else if (!head && loop) {
 372                 return NULL;
 373         }
 374
 375         while (head->processing) {
 376                 struct rb_node *node;
 377
 378                 node = rb_next(&head->href_node);
 379                 if (!node) {
 380                         if (loop)
 381                                 return NULL;
 382                         delayed_refs->run_delayed_start = 0;
 383                         start = 0;
 384                         loop = true;
 385                         goto again;
 386                 }
 387                 head = rb_entry(node, struct btrfs_delayed_ref_head,
 388                                 href_node);
 389         }
 390
 391         head->processing = 1;
 392         WARN_ON(delayed_refs->num_heads_ready == 0);
 393         delayed_refs->num_heads_ready--;
 394         delayed_refs->run_delayed_start = head->bytenr +
 395                 head->num_bytes;
 396         return head;
 397 }
 398
 399 /*
 400  * Helper to insert the ref_node to the tail or merge with tail.
 401  *
 402  * Return 0 for insert.
 403  * Return >0 for merge.
 404  */
 405 static int insert_delayed_ref(struct btrfs_trans_handle *trans,
 406                               struct btrfs_delayed_ref_root *root,
 407                               struct btrfs_delayed_ref_head *href,
 408                               struct btrfs_delayed_ref_node *ref)
 409 {
 410         struct btrfs_delayed_ref_node *exist;
 411         int mod;
 412         int ret = 0;
 413
 414         spin_lock(&href->lock);
 415         exist = tree_insert(&href->ref_tree, ref);
 416         if (!exist)
 417                 goto inserted;
 418
 419         /* Now we are sure we can merge */
 420         ret = 1;
 421         if (exist->action == ref->action) {
 422                 mod = ref->ref_mod;
 423         } else {
 424                 /* Need to change action */
 425                 if (exist->ref_mod < ref->ref_mod) {
 426                         exist->action = ref->action;
 427                         mod = -exist->ref_mod;
 428                         exist->ref_mod = ref->ref_mod;
 429                         if (ref->action == BTRFS_ADD_DELAYED_REF)
 430                                 list_add_tail(&exist->add_list,
 431                                               &href->ref_add_list);
 432                         else if (ref->action == BTRFS_DROP_DELAYED_REF) {
 433                                 ASSERT(!list_empty(&exist->add_list));
 434                                 list_del(&exist->add_list);
 435                         } else {
 436                                 ASSERT(0);
 437                         }
 438                 } else
 439                         mod = -ref->ref_mod;
 440         }
 441         exist->ref_mod += mod;
 442
 443         /* remove existing tail if its ref_mod is zero */
 444         if (exist->ref_mod == 0)
 445                 drop_delayed_ref(trans, root, href, exist);
 446         spin_unlock(&href->lock);
 447         return ret;
 448 inserted:
 449         if (ref->action == BTRFS_ADD_DELAYED_REF)
 450                 list_add_tail(&ref->add_list, &href->ref_add_list);
 451         atomic_inc(&root->num_entries);
 452         trans->delayed_ref_updates++;
 453         spin_unlock(&href->lock);
 454         return ret;
 455 }
 456
 457 /*
 458  * helper function to update the accounting in the head ref
 459  * existing and update must have the same bytenr
 460  */
 461 static noinline void
 462 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
 463                          struct btrfs_delayed_ref_head *existing,
 464                          struct btrfs_delayed_ref_head *update,
 465                          int *old_ref_mod_ret)
 466 {
 467         int old_ref_mod;
 468
 469         BUG_ON(existing->is_data != update->is_data);
 470
 471         spin_lock(&existing->lock);
 472         if (update->must_insert_reserved) {
 473                 /* if the extent was freed and then
 474                  * reallocated before the delayed ref
 475                  * entries were processed, we can end up
 476                  * with an existing head ref without
 477                  * the must_insert_reserved flag set.
 478                  * Set it again here
 479                  */
 480                 existing->must_insert_reserved = update->must_insert_reserved;
 481
 482                 /*
 483                  * update the num_bytes so we make sure the accounting
 484                  * is done correctly
 485                  */
 486                 existing->num_bytes = update->num_bytes;
 487
 488         }
 489
 490         if (update->extent_op) {
 491                 if (!existing->extent_op) {
 492                         existing->extent_op = update->extent_op;
 493                 } else {
 494                         if (update->extent_op->update_key) {
 495                                 memcpy(&existing->extent_op->key,
 496                                        &update->extent_op->key,
 497                                        sizeof(update->extent_op->key));
 498                                 existing->extent_op->update_key = true;
 499                         }
 500                         if (update->extent_op->update_flags) {
 501                                 existing->extent_op->flags_to_set |=
 502                                         update->extent_op->flags_to_set;
 503                                 existing->extent_op->update_flags = true;
 504                         }
 505                         btrfs_free_delayed_extent_op(update->extent_op);
 506                 }
 507         }
 508         /*
 509          * update the reference mod on the head to reflect this new operation,
 510          * only need the lock for this case cause we could be processing it
 511          * currently, for refs we just added we know we're a-ok.
 512          */
 513         old_ref_mod = existing->total_ref_mod;
 514         if (old_ref_mod_ret)
 515                 *old_ref_mod_ret = old_ref_mod;
 516         existing->ref_mod += update->ref_mod;
 517         existing->total_ref_mod += update->ref_mod;
 518
 519         /*
 520          * If we are going to from a positive ref mod to a negative or vice
 521          * versa we need to make sure to adjust pending_csums accordingly.
 522          */
 523         if (existing->is_data) {
 524                 if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
 525                         delayed_refs->pending_csums -= existing->num_bytes;
 526                 if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
 527                         delayed_refs->pending_csums += existing->num_bytes;
 528         }
 529         spin_unlock(&existing->lock);
 530 }
 531
 532 /*
 533  * helper function to actually insert a head node into the rbtree.
 534  * this does all the dirty work in terms of maintaining the correct
 535  * overall modification count.
 536  */
 537 static noinline struct btrfs_delayed_ref_head *
 538 add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 539                      struct btrfs_trans_handle *trans,
 540                      struct btrfs_delayed_ref_head *head_ref,
 541                      struct btrfs_qgroup_extent_record *qrecord,
 542                      u64 bytenr, u64 num_bytes, u64 ref_root, u64 reserved,
 543                      int action, int is_data, int is_system,
 544                      int *qrecord_inserted_ret,
 545                      int *old_ref_mod, int *new_ref_mod)
 546
 547 {
 548         struct btrfs_delayed_ref_head *existing;
 549         struct btrfs_delayed_ref_root *delayed_refs;
 550         int count_mod = 1;
 551         int must_insert_reserved = 0;
 552         int qrecord_inserted = 0;
 553
 554         /* If reserved is provided, it must be a data extent. */
 555         BUG_ON(!is_data && reserved);
 556
 557         /*
 558          * the head node stores the sum of all the mods, so dropping a ref
 559          * should drop the sum in the head node by one.
 560          */
 561         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 562                 count_mod = 0;
 563         else if (action == BTRFS_DROP_DELAYED_REF)
 564                 count_mod = -1;
 565
 566         /*
 567          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 568          * the reserved accounting when the extent is finally added, or
 569          * if a later modification deletes the delayed ref without ever
 570          * inserting the extent into the extent allocation tree.
 571          * ref->must_insert_reserved is the flag used to record
 572          * that accounting mods are required.
 573          *
 574          * Once we record must_insert_reserved, switch the action to
 575          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 576          */
 577         if (action == BTRFS_ADD_DELAYED_EXTENT)
 578                 must_insert_reserved = 1;
 579         else
 580                 must_insert_reserved = 0;
 581
 582         delayed_refs = &trans->transaction->delayed_refs;
 583
 584         refcount_set(&head_ref->refs, 1);
 585         head_ref->bytenr = bytenr;
 586         head_ref->num_bytes = num_bytes;
 587         head_ref->ref_mod = count_mod;
 588         head_ref->must_insert_reserved = must_insert_reserved;
 589         head_ref->is_data = is_data;
 590         head_ref->is_system = is_system;
 591         head_ref->ref_tree = RB_ROOT;
 592         INIT_LIST_HEAD(&head_ref->ref_add_list);
 593         RB_CLEAR_NODE(&head_ref->href_node);
 594         head_ref->processing = 0;
 595         head_ref->total_ref_mod = count_mod;
 596         head_ref->qgroup_reserved = 0;
 597         head_ref->qgroup_ref_root = 0;
 598         spin_lock_init(&head_ref->lock);
 599         mutex_init(&head_ref->mutex);
 600
 601         /* Record qgroup extent info if provided */
 602         if (qrecord) {
 603                 if (ref_root && reserved) {
 604                         head_ref->qgroup_ref_root = ref_root;
 605                         head_ref->qgroup_reserved = reserved;
 606                 }
 607
 608                 qrecord->bytenr = bytenr;
 609                 qrecord->num_bytes = num_bytes;
 610                 qrecord->old_roots = NULL;
 611
 612                 if(btrfs_qgroup_trace_extent_nolock(fs_info,
 613                                         delayed_refs, qrecord))
 614                         kfree(qrecord);
 615                 else
 616                         qrecord_inserted = 1;
 617         }
 618
 619         trace_add_delayed_ref_head(fs_info, head_ref, action);
 620
 621         existing = htree_insert(&delayed_refs->href_root,
 622                                 &head_ref->href_node);
 623         if (existing) {
 624                 WARN_ON(ref_root && reserved && existing->qgroup_ref_root
 625                         && existing->qgroup_reserved);
 626                 update_existing_head_ref(delayed_refs, existing, head_ref,
 627                                          old_ref_mod);
 628                 /*
 629                  * we've updated the existing ref, free the newly
 630                  * allocated ref
 631                  */
 632                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 633                 head_ref = existing;
 634         } else {
 635                 if (old_ref_mod)
 636                         *old_ref_mod = 0;
 637                 if (is_data && count_mod < 0)
 638                         delayed_refs->pending_csums += num_bytes;
 639                 delayed_refs->num_heads++;
 640                 delayed_refs->num_heads_ready++;
 641                 atomic_inc(&delayed_refs->num_entries);
 642                 trans->delayed_ref_updates++;
 643         }
 644         if (qrecord_inserted_ret)
 645                 *qrecord_inserted_ret = qrecord_inserted;
 646         if (new_ref_mod)
 647                 *new_ref_mod = head_ref->total_ref_mod;
 648         return head_ref;
 649 }
 650
 651 /*
 652  * helper to insert a delayed tree ref into the rbtree.
 653  */
 654 static noinline void
 655 add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 656                      struct btrfs_trans_handle *trans,
 657                      struct btrfs_delayed_ref_head *head_ref,
 658                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 659                      u64 num_bytes, u64 parent, u64 ref_root, int level,
 660                      int action)
 661 {
 662         struct btrfs_delayed_tree_ref *full_ref;
 663         struct btrfs_delayed_ref_root *delayed_refs;
 664         u64 seq = 0;
 665         int ret;
 666
 667         if (action == BTRFS_ADD_DELAYED_EXTENT)
 668                 action = BTRFS_ADD_DELAYED_REF;
 669
 670         if (is_fstree(ref_root))
 671                 seq = atomic64_read(&fs_info->tree_mod_seq);
 672         delayed_refs = &trans->transaction->delayed_refs;
 673
 674         /* first set the basic ref node struct up */
 675         refcount_set(&ref->refs, 1);
 676         ref->bytenr = bytenr;
 677         ref->num_bytes = num_bytes;
 678         ref->ref_mod = 1;
 679         ref->action = action;
 680         ref->is_head = 0;
 681         ref->in_tree = 1;
 682         ref->seq = seq;
 683         RB_CLEAR_NODE(&ref->ref_node);
 684         INIT_LIST_HEAD(&ref->add_list);
 685
 686         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 687         full_ref->parent = parent;
 688         full_ref->root = ref_root;
 689         if (parent)
 690                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 691         else
 692                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 693         full_ref->level = level;
 694
 695         trace_add_delayed_tree_ref(fs_info, ref, full_ref, action);
 696
 697         ret = insert_delayed_ref(trans, delayed_refs, head_ref, ref);
 698
 699         /*
 700          * XXX: memory should be freed at the same level allocated.
 701          * But bad practice is anywhere... Follow it now. Need cleanup.
 702          */
 703         if (ret > 0)
 704                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 705 }
 706
 707 /*
 708  * helper to insert a delayed data ref into the rbtree.
 709  */
 710 static noinline void
 711 add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 712                      struct btrfs_trans_handle *trans,
 713                      struct btrfs_delayed_ref_head *head_ref,
 714                      struct btrfs_delayed_ref_node *ref, u64 bytenr,
 715                      u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
 716                      u64 offset, int action)
 717 {
 718         struct btrfs_delayed_data_ref *full_ref;
 719         struct btrfs_delayed_ref_root *delayed_refs;
 720         u64 seq = 0;
 721         int ret;
 722
 723         if (action == BTRFS_ADD_DELAYED_EXTENT)
 724                 action = BTRFS_ADD_DELAYED_REF;
 725
 726         delayed_refs = &trans->transaction->delayed_refs;
 727
 728         if (is_fstree(ref_root))
 729                 seq = atomic64_read(&fs_info->tree_mod_seq);
 730
 731         /* first set the basic ref node struct up */
 732         refcount_set(&ref->refs, 1);
 733         ref->bytenr = bytenr;
 734         ref->num_bytes = num_bytes;
 735         ref->ref_mod = 1;
 736         ref->action = action;
 737         ref->is_head = 0;
 738         ref->in_tree = 1;
 739         ref->seq = seq;
 740         RB_CLEAR_NODE(&ref->ref_node);
 741         INIT_LIST_HEAD(&ref->add_list);
 742
 743         full_ref = btrfs_delayed_node_to_data_ref(ref);
 744         full_ref->parent = parent;
 745         full_ref->root = ref_root;
 746         if (parent)
 747                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 748         else
 749                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 750
 751         full_ref->objectid = owner;
 752         full_ref->offset = offset;
 753
 754         trace_add_delayed_data_ref(fs_info, ref, full_ref, action);
 755
 756         ret = insert_delayed_ref(trans, delayed_refs, head_ref, ref);
 757         if (ret > 0)
 758                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 759 }
 760
 761 /*
 762  * add a delayed tree ref.  This does all of the accounting required
 763  * to make sure the delayed ref is eventually processed before this
 764  * transaction commits.
 765  */
 766 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 767                                struct btrfs_trans_handle *trans,
 768                                u64 bytenr, u64 num_bytes, u64 parent,
 769                                u64 ref_root,  int level, int action,
 770                                struct btrfs_delayed_extent_op *extent_op,
 771                                int *old_ref_mod, int *new_ref_mod)
 772 {
 773         struct btrfs_delayed_tree_ref *ref;
 774         struct btrfs_delayed_ref_head *head_ref;
 775         struct btrfs_delayed_ref_root *delayed_refs;
 776         struct btrfs_qgroup_extent_record *record = NULL;
 777         int qrecord_inserted;
 778         int is_system = (ref_root == BTRFS_CHUNK_TREE_OBJECTID);
 779
 780         BUG_ON(extent_op && extent_op->is_data);
 781         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 782         if (!ref)
 783                 return -ENOMEM;
 784
 785         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 786         if (!head_ref)
 787                 goto free_ref;
 788
 789         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 790             is_fstree(ref_root)) {
 791                 record = kmalloc(sizeof(*record), GFP_NOFS);
 792                 if (!record)
 793                         goto free_head_ref;
 794         }
 795
 796         head_ref->extent_op = extent_op;
 797
 798         delayed_refs = &trans->transaction->delayed_refs;
 799         spin_lock(&delayed_refs->lock);
 800
 801         /*
 802          * insert both the head node and the new ref without dropping
 803          * the spin lock
 804          */
 805         head_ref = add_delayed_ref_head(fs_info, trans, head_ref, record,
 806                                         bytenr, num_bytes, 0, 0, action, 0,
 807                                         is_system, &qrecord_inserted,
 808                                         old_ref_mod, new_ref_mod);
 809
 810         add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 811                              num_bytes, parent, ref_root, level, action);
 812         spin_unlock(&delayed_refs->lock);
 813
 814         if (qrecord_inserted)
 815                 btrfs_qgroup_trace_extent_post(fs_info, record);
 816
 817         return 0;
 818
 819 free_head_ref:
 820         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 821 free_ref:
 822         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 823
 824         return -ENOMEM;
 825 }
 826
 827 /*
 828  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 829  */
 830 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 831                                struct btrfs_trans_handle *trans,
 832                                u64 bytenr, u64 num_bytes,
 833                                u64 parent, u64 ref_root,
 834                                u64 owner, u64 offset, u64 reserved, int action,
 835                                int *old_ref_mod, int *new_ref_mod)
 836 {
 837         struct btrfs_delayed_data_ref *ref;
 838         struct btrfs_delayed_ref_head *head_ref;
 839         struct btrfs_delayed_ref_root *delayed_refs;
 840         struct btrfs_qgroup_extent_record *record = NULL;
 841         int qrecord_inserted;
 842
 843         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 844         if (!ref)
 845                 return -ENOMEM;
 846
 847         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 848         if (!head_ref) {
 849                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 850                 return -ENOMEM;
 851         }
 852
 853         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
 854             is_fstree(ref_root)) {
 855                 record = kmalloc(sizeof(*record), GFP_NOFS);
 856                 if (!record) {
 857                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 858                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
 859                                         head_ref);
 860                         return -ENOMEM;
 861                 }
 862         }
 863
 864         head_ref->extent_op = NULL;
 865
 866         delayed_refs = &trans->transaction->delayed_refs;
 867         spin_lock(&delayed_refs->lock);
 868
 869         /*
 870          * insert both the head node and the new ref without dropping
 871          * the spin lock
 872          */
 873         head_ref = add_delayed_ref_head(fs_info, trans, head_ref, record,
 874                                         bytenr, num_bytes, ref_root, reserved,
 875                                         action, 1, 0, &qrecord_inserted,
 876                                         old_ref_mod, new_ref_mod);
 877
 878         add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 879                                    num_bytes, parent, ref_root, owner, offset,
 880                                    action);
 881         spin_unlock(&delayed_refs->lock);
 882
 883         if (qrecord_inserted)
 884                 return btrfs_qgroup_trace_extent_post(fs_info, record);
 885         return 0;
 886 }
 887
 888 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 889                                 struct btrfs_trans_handle *trans,
 890                                 u64 bytenr, u64 num_bytes,
 891                                 struct btrfs_delayed_extent_op *extent_op)
 892 {
 893         struct btrfs_delayed_ref_head *head_ref;
 894         struct btrfs_delayed_ref_root *delayed_refs;
 895
 896         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 897         if (!head_ref)
 898                 return -ENOMEM;
 899
 900         head_ref->extent_op = extent_op;
 901
 902         delayed_refs = &trans->transaction->delayed_refs;
 903         spin_lock(&delayed_refs->lock);
 904
 905         /*
 906          * extent_ops just modify the flags of an extent and they don't result
 907          * in ref count changes, hence it's safe to pass false/0 for is_system
 908          * argument
 909          */
 910         add_delayed_ref_head(fs_info, trans, head_ref, NULL, bytenr,
 911                              num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,
 912                              extent_op->is_data, 0, NULL, NULL, NULL);
 913
 914         spin_unlock(&delayed_refs->lock);
 915         return 0;
 916 }
 917
 918 /*
 919  * this does a simple search for the head node for a given extent.
 920  * It must be called with the delayed ref spinlock held, and it returns
 921  * the head node if any where found, or NULL if not.
 922  */
 923 struct btrfs_delayed_ref_head *
 924 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
 925 {
 926         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
 927 }
 928
 929 void __cold btrfs_delayed_ref_exit(void)
 930 {
 931         kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 932         kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 933         kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 934         kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 935 }
 936
 937 int __init btrfs_delayed_ref_init(void)
 938 {
 939         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 940                                 "btrfs_delayed_ref_head",
 941                                 sizeof(struct btrfs_delayed_ref_head), 0,
 942                                 SLAB_MEM_SPREAD, NULL);
 943         if (!btrfs_delayed_ref_head_cachep)
 944                 goto fail;
 945
 946         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 947                                 "btrfs_delayed_tree_ref",
 948                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 949                                 SLAB_MEM_SPREAD, NULL);
 950         if (!btrfs_delayed_tree_ref_cachep)
 951                 goto fail;
 952
 953         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 954                                 "btrfs_delayed_data_ref",
 955                                 sizeof(struct btrfs_delayed_data_ref), 0,
 956                                 SLAB_MEM_SPREAD, NULL);
 957         if (!btrfs_delayed_data_ref_cachep)
 958                 goto fail;
 959
 960         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 961                                 "btrfs_delayed_extent_op",
 962                                 sizeof(struct btrfs_delayed_extent_op), 0,
 963                                 SLAB_MEM_SPREAD, NULL);
 964         if (!btrfs_delayed_extent_op_cachep)
 965                 goto fail;
 966
 967         return 0;
 968 fail:
 969         btrfs_delayed_ref_exit();
 970         return -ENOMEM;
 971 }