fs/btrfs/delayed-inode.c

   1 /*
   2  * Copyright (C) 2011 Fujitsu.  All rights reserved.
   3  * Written by Miao Xie <miaox@cn.fujitsu.com>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public
   7  * License v2 as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public
  15  * License along with this program; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 021110-1307, USA.
  18  */
  19
  20 #include <linux/slab.h>
  21 #include "delayed-inode.h"
  22 #include "disk-io.h"
  23 #include "transaction.h"
  24
  25 #define BTRFS_DELAYED_WRITEBACK         400
  26 #define BTRFS_DELAYED_BACKGROUND        100
  27
  28 static struct kmem_cache *delayed_node_cache;
  29
  30 int __init btrfs_delayed_inode_init(void)
  31 {
  32         delayed_node_cache = kmem_cache_create("btrfs_delayed_node",
  33                                         sizeof(struct btrfs_delayed_node),
  34                                         0,
  35                                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
  36                                         NULL);
  37         if (!delayed_node_cache)
  38                 return -ENOMEM;
  39         return 0;
  40 }
  41
  42 void btrfs_delayed_inode_exit(void)
  43 {
  44         if (delayed_node_cache)
  45                 kmem_cache_destroy(delayed_node_cache);
  46 }
  47
  48 static inline void btrfs_init_delayed_node(
  49                                 struct btrfs_delayed_node *delayed_node,
  50                                 struct btrfs_root *root, u64 inode_id)
  51 {
  52         delayed_node->root = root;
  53         delayed_node->inode_id = inode_id;
  54         atomic_set(&delayed_node->refs, 0);
  55         delayed_node->count = 0;
  56         delayed_node->in_list = 0;
  57         delayed_node->inode_dirty = 0;
  58         delayed_node->ins_root = RB_ROOT;
  59         delayed_node->del_root = RB_ROOT;
  60         mutex_init(&delayed_node->mutex);
  61         delayed_node->index_cnt = 0;
  62         INIT_LIST_HEAD(&delayed_node->n_list);
  63         INIT_LIST_HEAD(&delayed_node->p_list);
  64         delayed_node->bytes_reserved = 0;
  65         memset(&delayed_node->inode_item, 0, sizeof(delayed_node->inode_item));
  66 }
  67
  68 static inline int btrfs_is_continuous_delayed_item(
  69                                         struct btrfs_delayed_item *item1,
  70                                         struct btrfs_delayed_item *item2)
  71 {
  72         if (item1->key.type == BTRFS_DIR_INDEX_KEY &&
  73             item1->key.objectid == item2->key.objectid &&
  74             item1->key.type == item2->key.type &&
  75             item1->key.offset + 1 == item2->key.offset)
  76                 return 1;
  77         return 0;
  78 }
  79
  80 static inline struct btrfs_delayed_root *btrfs_get_delayed_root(
  81                                                         struct btrfs_root *root)
  82 {
  83         return root->fs_info->delayed_root;
  84 }
  85
  86 static struct btrfs_delayed_node *btrfs_get_delayed_node(struct inode *inode)
  87 {
  88         struct btrfs_inode *btrfs_inode = BTRFS_I(inode);
  89         struct btrfs_root *root = btrfs_inode->root;
  90         u64 ino = btrfs_ino(inode);
  91         struct btrfs_delayed_node *node;
  92
  93         node = ACCESS_ONCE(btrfs_inode->delayed_node);
  94         if (node) {
  95                 atomic_inc(&node->refs);
  96                 return node;
  97         }
  98
  99         spin_lock(&root->inode_lock);
 100         node = radix_tree_lookup(&root->delayed_nodes_tree, ino);
 101         if (node) {
 102                 if (btrfs_inode->delayed_node) {
 103                         atomic_inc(&node->refs);        /* can be accessed */
 104                         BUG_ON(btrfs_inode->delayed_node != node);
 105                         spin_unlock(&root->inode_lock);
 106                         return node;
 107                 }
 108                 btrfs_inode->delayed_node = node;
 109                 atomic_inc(&node->refs);        /* can be accessed */
 110                 atomic_inc(&node->refs);        /* cached in the inode */
 111                 spin_unlock(&root->inode_lock);
 112                 return node;
 113         }
 114         spin_unlock(&root->inode_lock);
 115
 116         return NULL;
 117 }
 118
 119 /* Will return either the node or PTR_ERR(-ENOMEM) */
 120 static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
 121                                                         struct inode *inode)
 122 {
 123         struct btrfs_delayed_node *node;
 124         struct btrfs_inode *btrfs_inode = BTRFS_I(inode);
 125         struct btrfs_root *root = btrfs_inode->root;
 126         u64 ino = btrfs_ino(inode);
 127         int ret;
 128
 129 again:
 130         node = btrfs_get_delayed_node(inode);
 131         if (node)
 132                 return node;
 133
 134         node = kmem_cache_alloc(delayed_node_cache, GFP_NOFS);
 135         if (!node)
 136                 return ERR_PTR(-ENOMEM);
 137         btrfs_init_delayed_node(node, root, ino);
 138
 139         atomic_inc(&node->refs);        /* cached in the btrfs inode */
 140         atomic_inc(&node->refs);        /* can be accessed */
 141
 142         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
 143         if (ret) {
 144                 kmem_cache_free(delayed_node_cache, node);
 145                 return ERR_PTR(ret);
 146         }
 147
 148         spin_lock(&root->inode_lock);
 149         ret = radix_tree_insert(&root->delayed_nodes_tree, ino, node);
 150         if (ret == -EEXIST) {
 151                 kmem_cache_free(delayed_node_cache, node);
 152                 spin_unlock(&root->inode_lock);
 153                 radix_tree_preload_end();
 154                 goto again;
 155         }
 156         btrfs_inode->delayed_node = node;
 157         spin_unlock(&root->inode_lock);
 158         radix_tree_preload_end();
 159
 160         return node;
 161 }
 162
 163 /*
 164  * Call it when holding delayed_node->mutex
 165  *
 166  * If mod = 1, add this node into the prepared list.
 167  */
 168 static void btrfs_queue_delayed_node(struct btrfs_delayed_root *root,
 169                                      struct btrfs_delayed_node *node,
 170                                      int mod)
 171 {
 172         spin_lock(&root->lock);
 173         if (node->in_list) {
 174                 if (!list_empty(&node->p_list))
 175                         list_move_tail(&node->p_list, &root->prepare_list);
 176                 else if (mod)
 177                         list_add_tail(&node->p_list, &root->prepare_list);
 178         } else {
 179                 list_add_tail(&node->n_list, &root->node_list);
 180                 list_add_tail(&node->p_list, &root->prepare_list);
 181                 atomic_inc(&node->refs);        /* inserted into list */
 182                 root->nodes++;
 183                 node->in_list = 1;
 184         }
 185         spin_unlock(&root->lock);
 186 }
 187
 188 /* Call it when holding delayed_node->mutex */
 189 static void btrfs_dequeue_delayed_node(struct btrfs_delayed_root *root,
 190                                        struct btrfs_delayed_node *node)
 191 {
 192         spin_lock(&root->lock);
 193         if (node->in_list) {
 194                 root->nodes--;
 195                 atomic_dec(&node->refs);        /* not in the list */
 196                 list_del_init(&node->n_list);
 197                 if (!list_empty(&node->p_list))
 198                         list_del_init(&node->p_list);
 199                 node->in_list = 0;
 200         }
 201         spin_unlock(&root->lock);
 202 }
 203
 204 struct btrfs_delayed_node *btrfs_first_delayed_node(
 205                         struct btrfs_delayed_root *delayed_root)
 206 {
 207         struct list_head *p;
 208         struct btrfs_delayed_node *node = NULL;
 209
 210         spin_lock(&delayed_root->lock);
 211         if (list_empty(&delayed_root->node_list))
 212                 goto out;
 213
 214         p = delayed_root->node_list.next;
 215         node = list_entry(p, struct btrfs_delayed_node, n_list);
 216         atomic_inc(&node->refs);
 217 out:
 218         spin_unlock(&delayed_root->lock);
 219
 220         return node;
 221 }
 222
 223 struct btrfs_delayed_node *btrfs_next_delayed_node(
 224                                                 struct btrfs_delayed_node *node)
 225 {
 226         struct btrfs_delayed_root *delayed_root;
 227         struct list_head *p;
 228         struct btrfs_delayed_node *next = NULL;
 229
 230         delayed_root = node->root->fs_info->delayed_root;
 231         spin_lock(&delayed_root->lock);
 232         if (!node->in_list) {   /* not in the list */
 233                 if (list_empty(&delayed_root->node_list))
 234                         goto out;
 235                 p = delayed_root->node_list.next;
 236         } else if (list_is_last(&node->n_list, &delayed_root->node_list))
 237                 goto out;
 238         else
 239                 p = node->n_list.next;
 240
 241         next = list_entry(p, struct btrfs_delayed_node, n_list);
 242         atomic_inc(&next->refs);
 243 out:
 244         spin_unlock(&delayed_root->lock);
 245
 246         return next;
 247 }
 248
 249 static void __btrfs_release_delayed_node(
 250                                 struct btrfs_delayed_node *delayed_node,
 251                                 int mod)
 252 {
 253         struct btrfs_delayed_root *delayed_root;
 254
 255         if (!delayed_node)
 256                 return;
 257
 258         delayed_root = delayed_node->root->fs_info->delayed_root;
 259
 260         mutex_lock(&delayed_node->mutex);
 261         if (delayed_node->count)
 262                 btrfs_queue_delayed_node(delayed_root, delayed_node, mod);
 263         else
 264                 btrfs_dequeue_delayed_node(delayed_root, delayed_node);
 265         mutex_unlock(&delayed_node->mutex);
 266
 267         if (atomic_dec_and_test(&delayed_node->refs)) {
 268                 struct btrfs_root *root = delayed_node->root;
 269                 spin_lock(&root->inode_lock);
 270                 if (atomic_read(&delayed_node->refs) == 0) {
 271                         radix_tree_delete(&root->delayed_nodes_tree,
 272                                           delayed_node->inode_id);
 273                         kmem_cache_free(delayed_node_cache, delayed_node);
 274                 }
 275                 spin_unlock(&root->inode_lock);
 276         }
 277 }
 278
 279 static inline void btrfs_release_delayed_node(struct btrfs_delayed_node *node)
 280 {
 281         __btrfs_release_delayed_node(node, 0);
 282 }
 283
 284 struct btrfs_delayed_node *btrfs_first_prepared_delayed_node(
 285                                         struct btrfs_delayed_root *delayed_root)
 286 {
 287         struct list_head *p;
 288         struct btrfs_delayed_node *node = NULL;
 289
 290         spin_lock(&delayed_root->lock);
 291         if (list_empty(&delayed_root->prepare_list))
 292                 goto out;
 293
 294         p = delayed_root->prepare_list.next;
 295         list_del_init(p);
 296         node = list_entry(p, struct btrfs_delayed_node, p_list);
 297         atomic_inc(&node->refs);
 298 out:
 299         spin_unlock(&delayed_root->lock);
 300
 301         return node;
 302 }
 303
 304 static inline void btrfs_release_prepared_delayed_node(
 305                                         struct btrfs_delayed_node *node)
 306 {
 307         __btrfs_release_delayed_node(node, 1);
 308 }
 309
 310 struct btrfs_delayed_item *btrfs_alloc_delayed_item(u32 data_len)
 311 {
 312         struct btrfs_delayed_item *item;
 313         item = kmalloc(sizeof(*item) + data_len, GFP_NOFS);
 314         if (item) {
 315                 item->data_len = data_len;
 316                 item->ins_or_del = 0;
 317                 item->bytes_reserved = 0;
 318                 item->delayed_node = NULL;
 319                 atomic_set(&item->refs, 1);
 320         }
 321         return item;
 322 }
 323
 324 /*
 325  * __btrfs_lookup_delayed_item - look up the delayed item by key
 326  * @delayed_node: pointer to the delayed node
 327  * @key:          the key to look up
 328  * @prev:         used to store the prev item if the right item isn't found
 329  * @next:         used to store the next item if the right item isn't found
 330  *
 331  * Note: if we don't find the right item, we will return the prev item and
 332  * the next item.
 333  */
 334 static struct btrfs_delayed_item *__btrfs_lookup_delayed_item(
 335                                 struct rb_root *root,
 336                                 struct btrfs_key *key,
 337                                 struct btrfs_delayed_item **prev,
 338                                 struct btrfs_delayed_item **next)
 339 {
 340         struct rb_node *node, *prev_node = NULL;
 341         struct btrfs_delayed_item *delayed_item = NULL;
 342         int ret = 0;
 343
 344         node = root->rb_node;
 345
 346         while (node) {
 347                 delayed_item = rb_entry(node, struct btrfs_delayed_item,
 348                                         rb_node);
 349                 prev_node = node;
 350                 ret = btrfs_comp_cpu_keys(&delayed_item->key, key);
 351                 if (ret < 0)
 352                         node = node->rb_right;
 353                 else if (ret > 0)
 354                         node = node->rb_left;
 355                 else
 356                         return delayed_item;
 357         }
 358
 359         if (prev) {
 360                 if (!prev_node)
 361                         *prev = NULL;
 362                 else if (ret < 0)
 363                         *prev = delayed_item;
 364                 else if ((node = rb_prev(prev_node)) != NULL) {
 365                         *prev = rb_entry(node, struct btrfs_delayed_item,
 366                                          rb_node);
 367                 } else
 368                         *prev = NULL;
 369         }
 370
 371         if (next) {
 372                 if (!prev_node)
 373                         *next = NULL;
 374                 else if (ret > 0)
 375                         *next = delayed_item;
 376                 else if ((node = rb_next(prev_node)) != NULL) {
 377                         *next = rb_entry(node, struct btrfs_delayed_item,
 378                                          rb_node);
 379                 } else
 380                         *next = NULL;
 381         }
 382         return NULL;
 383 }
 384
 385 struct btrfs_delayed_item *__btrfs_lookup_delayed_insertion_item(
 386                                         struct btrfs_delayed_node *delayed_node,
 387                                         struct btrfs_key *key)
 388 {
 389         struct btrfs_delayed_item *item;
 390
 391         item = __btrfs_lookup_delayed_item(&delayed_node->ins_root, key,
 392                                            NULL, NULL);
 393         return item;
 394 }
 395
 396 struct btrfs_delayed_item *__btrfs_lookup_delayed_deletion_item(
 397                                         struct btrfs_delayed_node *delayed_node,
 398                                         struct btrfs_key *key)
 399 {
 400         struct btrfs_delayed_item *item;
 401
 402         item = __btrfs_lookup_delayed_item(&delayed_node->del_root, key,
 403                                            NULL, NULL);
 404         return item;
 405 }
 406
 407 struct btrfs_delayed_item *__btrfs_search_delayed_insertion_item(
 408                                         struct btrfs_delayed_node *delayed_node,
 409                                         struct btrfs_key *key)
 410 {
 411         struct btrfs_delayed_item *item, *next;
 412
 413         item = __btrfs_lookup_delayed_item(&delayed_node->ins_root, key,
 414                                            NULL, &next);
 415         if (!item)
 416                 item = next;
 417
 418         return item;
 419 }
 420
 421 struct btrfs_delayed_item *__btrfs_search_delayed_deletion_item(
 422                                         struct btrfs_delayed_node *delayed_node,
 423                                         struct btrfs_key *key)
 424 {
 425         struct btrfs_delayed_item *item, *next;
 426
 427         item = __btrfs_lookup_delayed_item(&delayed_node->del_root, key,
 428                                            NULL, &next);
 429         if (!item)
 430                 item = next;
 431
 432         return item;
 433 }
 434
 435 static int __btrfs_add_delayed_item(struct btrfs_delayed_node *delayed_node,
 436                                     struct btrfs_delayed_item *ins,
 437                                     int action)
 438 {
 439         struct rb_node **p, *node;
 440         struct rb_node *parent_node = NULL;
 441         struct rb_root *root;
 442         struct btrfs_delayed_item *item;
 443         int cmp;
 444
 445         if (action == BTRFS_DELAYED_INSERTION_ITEM)
 446                 root = &delayed_node->ins_root;
 447         else if (action == BTRFS_DELAYED_DELETION_ITEM)
 448                 root = &delayed_node->del_root;
 449         else
 450                 BUG();
 451         p = &root->rb_node;
 452         node = &ins->rb_node;
 453
 454         while (*p) {
 455                 parent_node = *p;
 456                 item = rb_entry(parent_node, struct btrfs_delayed_item,
 457                                  rb_node);
 458
 459                 cmp = btrfs_comp_cpu_keys(&item->key, &ins->key);
 460                 if (cmp < 0)
 461                         p = &(*p)->rb_right;
 462                 else if (cmp > 0)
 463                         p = &(*p)->rb_left;
 464                 else
 465                         return -EEXIST;
 466         }
 467
 468         rb_link_node(node, parent_node, p);
 469         rb_insert_color(node, root);
 470         ins->delayed_node = delayed_node;
 471         ins->ins_or_del = action;
 472
 473         if (ins->key.type == BTRFS_DIR_INDEX_KEY &&
 474             action == BTRFS_DELAYED_INSERTION_ITEM &&
 475             ins->key.offset >= delayed_node->index_cnt)
 476                         delayed_node->index_cnt = ins->key.offset + 1;
 477
 478         delayed_node->count++;
 479         atomic_inc(&delayed_node->root->fs_info->delayed_root->items);
 480         return 0;
 481 }
 482
 483 static int __btrfs_add_delayed_insertion_item(struct btrfs_delayed_node *node,
 484                                               struct btrfs_delayed_item *item)
 485 {
 486         return __btrfs_add_delayed_item(node, item,
 487                                         BTRFS_DELAYED_INSERTION_ITEM);
 488 }
 489
 490 static int __btrfs_add_delayed_deletion_item(struct btrfs_delayed_node *node,
 491                                              struct btrfs_delayed_item *item)
 492 {
 493         return __btrfs_add_delayed_item(node, item,
 494                                         BTRFS_DELAYED_DELETION_ITEM);
 495 }
 496
 497 static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item)
 498 {
 499         struct rb_root *root;
 500         struct btrfs_delayed_root *delayed_root;
 501
 502         delayed_root = delayed_item->delayed_node->root->fs_info->delayed_root;
 503
 504         BUG_ON(!delayed_root);
 505         BUG_ON(delayed_item->ins_or_del != BTRFS_DELAYED_DELETION_ITEM &&
 506                delayed_item->ins_or_del != BTRFS_DELAYED_INSERTION_ITEM);
 507
 508         if (delayed_item->ins_or_del == BTRFS_DELAYED_INSERTION_ITEM)
 509                 root = &delayed_item->delayed_node->ins_root;
 510         else
 511                 root = &delayed_item->delayed_node->del_root;
 512
 513         rb_erase(&delayed_item->rb_node, root);
 514         delayed_item->delayed_node->count--;
 515         if (atomic_dec_return(&delayed_root->items) <
 516             BTRFS_DELAYED_BACKGROUND &&
 517             waitqueue_active(&delayed_root->wait))
 518                 wake_up(&delayed_root->wait);
 519 }
 520
 521 static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
 522 {
 523         if (item) {
 524                 __btrfs_remove_delayed_item(item);
 525                 if (atomic_dec_and_test(&item->refs))
 526                         kfree(item);
 527         }
 528 }
 529
 530 struct btrfs_delayed_item *__btrfs_first_delayed_insertion_item(
 531                                         struct btrfs_delayed_node *delayed_node)
 532 {
 533         struct rb_node *p;
 534         struct btrfs_delayed_item *item = NULL;
 535
 536         p = rb_first(&delayed_node->ins_root);
 537         if (p)
 538                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 539
 540         return item;
 541 }
 542
 543 struct btrfs_delayed_item *__btrfs_first_delayed_deletion_item(
 544                                         struct btrfs_delayed_node *delayed_node)
 545 {
 546         struct rb_node *p;
 547         struct btrfs_delayed_item *item = NULL;
 548
 549         p = rb_first(&delayed_node->del_root);
 550         if (p)
 551                 item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 552
 553         return item;
 554 }
 555
 556 struct btrfs_delayed_item *__btrfs_next_delayed_item(
 557                                                 struct btrfs_delayed_item *item)
 558 {
 559         struct rb_node *p;
 560         struct btrfs_delayed_item *next = NULL;
 561
 562         p = rb_next(&item->rb_node);
 563         if (p)
 564                 next = rb_entry(p, struct btrfs_delayed_item, rb_node);
 565
 566         return next;
 567 }
 568
 569 static inline struct btrfs_root *btrfs_get_fs_root(struct btrfs_root *root,
 570                                                    u64 root_id)
 571 {
 572         struct btrfs_key root_key;
 573
 574         if (root->objectid == root_id)
 575                 return root;
 576
 577         root_key.objectid = root_id;
 578         root_key.type = BTRFS_ROOT_ITEM_KEY;
 579         root_key.offset = (u64)-1;
 580         return btrfs_read_fs_root_no_name(root->fs_info, &root_key);
 581 }
 582
 583 static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
 584                                                struct btrfs_root *root,
 585                                                struct btrfs_delayed_item *item)
 586 {
 587         struct btrfs_block_rsv *src_rsv;
 588         struct btrfs_block_rsv *dst_rsv;
 589         u64 num_bytes;
 590         int ret;
 591
 592         if (!trans->bytes_reserved)
 593                 return 0;
 594
 595         src_rsv = trans->block_rsv;
 596         dst_rsv = &root->fs_info->delayed_block_rsv;
 597
 598         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
 599         ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes);
 600         if (!ret) {
 601                 trace_btrfs_space_reservation(root->fs_info, "delayed_item",
 602                                               item->key.objectid,
 603                                               num_bytes, 1);
 604                 item->bytes_reserved = num_bytes;
 605         }
 606
 607         return ret;
 608 }
 609
 610 static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
 611                                                 struct btrfs_delayed_item *item)
 612 {
 613         struct btrfs_block_rsv *rsv;
 614
 615         if (!item->bytes_reserved)
 616                 return;
 617
 618         rsv = &root->fs_info->delayed_block_rsv;
 619         trace_btrfs_space_reservation(root->fs_info, "delayed_item",
 620                                       item->key.objectid, item->bytes_reserved,
 621                                       0);
 622         btrfs_block_rsv_release(root, rsv,
 623                                 item->bytes_reserved);
 624 }
 625
 626 static int btrfs_delayed_inode_reserve_metadata(
 627                                         struct btrfs_trans_handle *trans,
 628                                         struct btrfs_root *root,
 629                                         struct inode *inode,
 630                                         struct btrfs_delayed_node *node)
 631 {
 632         struct btrfs_block_rsv *src_rsv;
 633         struct btrfs_block_rsv *dst_rsv;
 634         u64 num_bytes;
 635         int ret;
 636         bool release = false;
 637
 638         src_rsv = trans->block_rsv;
 639         dst_rsv = &root->fs_info->delayed_block_rsv;
 640
 641         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
 642
 643         /*
 644          * btrfs_dirty_inode will update the inode under btrfs_join_transaction
 645          * which doesn't reserve space for speed.  This is a problem since we
 646          * still need to reserve space for this update, so try to reserve the
 647          * space.
 648          *
 649          * Now if src_rsv == delalloc_block_rsv we'll let it just steal since
 650          * we're accounted for.
 651          */
 652         if (!src_rsv || (!trans->bytes_reserved &&
 653                          src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) {
 654                 ret = btrfs_block_rsv_add_noflush(root, dst_rsv, num_bytes);
 655                 /*
 656                  * Since we're under a transaction reserve_metadata_bytes could
 657                  * try to commit the transaction which will make it return
 658                  * EAGAIN to make us stop the transaction we have, so return
 659                  * ENOSPC instead so that btrfs_dirty_inode knows what to do.
 660                  */
 661                 if (ret == -EAGAIN)
 662                         ret = -ENOSPC;
 663                 if (!ret) {
 664                         node->bytes_reserved = num_bytes;
 665                         trace_btrfs_space_reservation(root->fs_info,
 666                                                       "delayed_inode",
 667                                                       btrfs_ino(inode),
 668                                                       num_bytes, 1);
 669                 }
 670                 return ret;
 671         } else if (src_rsv->type == BTRFS_BLOCK_RSV_DELALLOC) {
 672                 spin_lock(&BTRFS_I(inode)->lock);
 673                 if (test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
 674                                        &BTRFS_I(inode)->runtime_flags)) {
 675                         spin_unlock(&BTRFS_I(inode)->lock);
 676                         release = true;
 677                         goto migrate;
 678                 }
 679                 spin_unlock(&BTRFS_I(inode)->lock);
 680
 681                 /* Ok we didn't have space pre-reserved.  This shouldn't happen
 682                  * too often but it can happen if we do delalloc to an existing
 683                  * inode which gets dirtied because of the time update, and then
 684                  * isn't touched again until after the transaction commits and
 685                  * then we try to write out the data.  First try to be nice and
 686                  * reserve something strictly for us.  If not be a pain and try
 687                  * to steal from the delalloc block rsv.
 688                  */
 689                 ret = btrfs_block_rsv_add_noflush(root, dst_rsv, num_bytes);
 690                 if (!ret)
 691                         goto out;
 692
 693                 ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes);
 694                 if (!ret)
 695                         goto out;
 696
 697                 /*
 698                  * Ok this is a problem, let's just steal from the global rsv
 699                  * since this really shouldn't happen that often.
 700                  */
 701                 WARN_ON(1);
 702                 ret = btrfs_block_rsv_migrate(&root->fs_info->global_block_rsv,
 703                                               dst_rsv, num_bytes);
 704                 goto out;
 705         }
 706
 707 migrate:
 708         ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes);
 709
 710 out:
 711         /*
 712          * Migrate only takes a reservation, it doesn't touch the size of the
 713          * block_rsv.  This is to simplify people who don't normally have things
 714          * migrated from their block rsv.  If they go to release their
 715          * reservation, that will decrease the size as well, so if migrate
 716          * reduced size we'd end up with a negative size.  But for the
 717          * delalloc_meta_reserved stuff we will only know to drop 1 reservation,
 718          * but we could in fact do this reserve/migrate dance several times
 719          * between the time we did the original reservation and we'd clean it
 720          * up.  So to take care of this, release the space for the meta
 721          * reservation here.  I think it may be time for a documentation page on
 722          * how block rsvs. work.
 723          */
 724         if (!ret) {
 725                 trace_btrfs_space_reservation(root->fs_info, "delayed_inode",
 726                                               btrfs_ino(inode), num_bytes, 1);
 727                 node->bytes_reserved = num_bytes;
 728         }
 729
 730         if (release) {
 731                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
 732                                               btrfs_ino(inode), num_bytes, 0);
 733                 btrfs_block_rsv_release(root, src_rsv, num_bytes);
 734         }
 735
 736         return ret;
 737 }
 738
 739 static void btrfs_delayed_inode_release_metadata(struct btrfs_root *root,
 740                                                 struct btrfs_delayed_node *node)
 741 {
 742         struct btrfs_block_rsv *rsv;
 743
 744         if (!node->bytes_reserved)
 745                 return;
 746
 747         rsv = &root->fs_info->delayed_block_rsv;
 748         trace_btrfs_space_reservation(root->fs_info, "delayed_inode",
 749                                       node->inode_id, node->bytes_reserved, 0);
 750         btrfs_block_rsv_release(root, rsv,
 751                                 node->bytes_reserved);
 752         node->bytes_reserved = 0;
 753 }
 754
 755 /*
 756  * This helper will insert some continuous items into the same leaf according
 757  * to the free space of the leaf.
 758  */
 759 static int btrfs_batch_insert_items(struct btrfs_trans_handle *trans,
 760                                 struct btrfs_root *root,
 761                                 struct btrfs_path *path,
 762                                 struct btrfs_delayed_item *item)
 763 {
 764         struct btrfs_delayed_item *curr, *next;
 765         int free_space;
 766         int total_data_size = 0, total_size = 0;
 767         struct extent_buffer *leaf;
 768         char *data_ptr;
 769         struct btrfs_key *keys;
 770         u32 *data_size;
 771         struct list_head head;
 772         int slot;
 773         int nitems;
 774         int i;
 775         int ret = 0;
 776
 777         BUG_ON(!path->nodes[0]);
 778
 779         leaf = path->nodes[0];
 780         free_space = btrfs_leaf_free_space(root, leaf);
 781         INIT_LIST_HEAD(&head);
 782
 783         next = item;
 784         nitems = 0;
 785
 786         /*
 787          * count the number of the continuous items that we can insert in batch
 788          */
 789         while (total_size + next->data_len + sizeof(struct btrfs_item) <=
 790                free_space) {
 791                 total_data_size += next->data_len;
 792                 total_size += next->data_len + sizeof(struct btrfs_item);
 793                 list_add_tail(&next->tree_list, &head);
 794                 nitems++;
 795
 796                 curr = next;
 797                 next = __btrfs_next_delayed_item(curr);
 798                 if (!next)
 799                         break;
 800
 801                 if (!btrfs_is_continuous_delayed_item(curr, next))
 802                         break;
 803         }
 804
 805         if (!nitems) {
 806                 ret = 0;
 807                 goto out;
 808         }
 809
 810         /*
 811          * we need allocate some memory space, but it might cause the task
 812          * to sleep, so we set all locked nodes in the path to blocking locks
 813          * first.
 814          */
 815         btrfs_set_path_blocking(path);
 816
 817         keys = kmalloc(sizeof(struct btrfs_key) * nitems, GFP_NOFS);
 818         if (!keys) {
 819                 ret = -ENOMEM;
 820                 goto out;
 821         }
 822
 823         data_size = kmalloc(sizeof(u32) * nitems, GFP_NOFS);
 824         if (!data_size) {
 825                 ret = -ENOMEM;
 826                 goto error;
 827         }
 828
 829         /* get keys of all the delayed items */
 830         i = 0;
 831         list_for_each_entry(next, &head, tree_list) {
 832                 keys[i] = next->key;
 833                 data_size[i] = next->data_len;
 834                 i++;
 835         }
 836
 837         /* reset all the locked nodes in the patch to spinning locks. */
 838         btrfs_clear_path_blocking(path, NULL, 0);
 839
 840         /* insert the keys of the items */
 841         setup_items_for_insert(trans, root, path, keys, data_size,
 842                                total_data_size, total_size, nitems);
 843
 844         /* insert the dir index items */
 845         slot = path->slots[0];
 846         list_for_each_entry_safe(curr, next, &head, tree_list) {
 847                 data_ptr = btrfs_item_ptr(leaf, slot, char);
 848                 write_extent_buffer(leaf, &curr->data,
 849                                     (unsigned long)data_ptr,
 850                                     curr->data_len);
 851                 slot++;
 852
 853                 btrfs_delayed_item_release_metadata(root, curr);
 854
 855                 list_del(&curr->tree_list);
 856                 btrfs_release_delayed_item(curr);
 857         }
 858
 859 error:
 860         kfree(data_size);
 861         kfree(keys);
 862 out:
 863         return ret;
 864 }
 865
 866 /*
 867  * This helper can just do simple insertion that needn't extend item for new
 868  * data, such as directory name index insertion, inode insertion.
 869  */
 870 static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 871                                      struct btrfs_root *root,
 872                                      struct btrfs_path *path,
 873                                      struct btrfs_delayed_item *delayed_item)
 874 {
 875         struct extent_buffer *leaf;
 876         struct btrfs_item *item;
 877         char *ptr;
 878         int ret;
 879
 880         ret = btrfs_insert_empty_item(trans, root, path, &delayed_item->key,
 881                                       delayed_item->data_len);
 882         if (ret < 0 && ret != -EEXIST)
 883                 return ret;
 884
 885         leaf = path->nodes[0];
 886
 887         item = btrfs_item_nr(leaf, path->slots[0]);
 888         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
 889
 890         write_extent_buffer(leaf, delayed_item->data, (unsigned long)ptr,
 891                             delayed_item->data_len);
 892         btrfs_mark_buffer_dirty(leaf);
 893
 894         btrfs_delayed_item_release_metadata(root, delayed_item);
 895         return 0;
 896 }
 897
 898 /*
 899  * we insert an item first, then if there are some continuous items, we try
 900  * to insert those items into the same leaf.
 901  */
 902 static int btrfs_insert_delayed_items(struct btrfs_trans_handle *trans,
 903                                       struct btrfs_path *path,
 904                                       struct btrfs_root *root,
 905                                       struct btrfs_delayed_node *node)
 906 {
 907         struct btrfs_delayed_item *curr, *prev;
 908         int ret = 0;
 909
 910 do_again:
 911         mutex_lock(&node->mutex);
 912         curr = __btrfs_first_delayed_insertion_item(node);
 913         if (!curr)
 914                 goto insert_end;
 915
 916         ret = btrfs_insert_delayed_item(trans, root, path, curr);
 917         if (ret < 0) {
 918                 btrfs_release_path(path);
 919                 goto insert_end;
 920         }
 921
 922         prev = curr;
 923         curr = __btrfs_next_delayed_item(prev);
 924         if (curr && btrfs_is_continuous_delayed_item(prev, curr)) {
 925                 /* insert the continuous items into the same leaf */
 926                 path->slots[0]++;
 927                 btrfs_batch_insert_items(trans, root, path, curr);
 928         }
 929         btrfs_release_delayed_item(prev);
 930         btrfs_mark_buffer_dirty(path->nodes[0]);
 931
 932         btrfs_release_path(path);
 933         mutex_unlock(&node->mutex);
 934         goto do_again;
 935
 936 insert_end:
 937         mutex_unlock(&node->mutex);
 938         return ret;
 939 }
 940
 941 static int btrfs_batch_delete_items(struct btrfs_trans_handle *trans,
 942                                     struct btrfs_root *root,
 943                                     struct btrfs_path *path,
 944                                     struct btrfs_delayed_item *item)
 945 {
 946         struct btrfs_delayed_item *curr, *next;
 947         struct extent_buffer *leaf;
 948         struct btrfs_key key;
 949         struct list_head head;
 950         int nitems, i, last_item;
 951         int ret = 0;
 952
 953         BUG_ON(!path->nodes[0]);
 954
 955         leaf = path->nodes[0];
 956
 957         i = path->slots[0];
 958         last_item = btrfs_header_nritems(leaf) - 1;
 959         if (i > last_item)
 960                 return -ENOENT; /* FIXME: Is errno suitable? */
 961
 962         next = item;
 963         INIT_LIST_HEAD(&head);
 964         btrfs_item_key_to_cpu(leaf, &key, i);
 965         nitems = 0;
 966         /*
 967          * count the number of the dir index items that we can delete in batch
 968          */
 969         while (btrfs_comp_cpu_keys(&next->key, &key) == 0) {
 970                 list_add_tail(&next->tree_list, &head);
 971                 nitems++;
 972
 973                 curr = next;
 974                 next = __btrfs_next_delayed_item(curr);
 975                 if (!next)
 976                         break;
 977
 978                 if (!btrfs_is_continuous_delayed_item(curr, next))
 979                         break;
 980
 981                 i++;
 982                 if (i > last_item)
 983                         break;
 984                 btrfs_item_key_to_cpu(leaf, &key, i);
 985         }
 986
 987         if (!nitems)
 988                 return 0;
 989
 990         ret = btrfs_del_items(trans, root, path, path->slots[0], nitems);
 991         if (ret)
 992                 goto out;
 993
 994         list_for_each_entry_safe(curr, next, &head, tree_list) {
 995                 btrfs_delayed_item_release_metadata(root, curr);
 996                 list_del(&curr->tree_list);
 997                 btrfs_release_delayed_item(curr);
 998         }
 999
1000 out:
1001         return ret;
1002 }
1003
1004 static int btrfs_delete_delayed_items(struct btrfs_trans_handle *trans,
1005                                       struct btrfs_path *path,
1006                                       struct btrfs_root *root,
1007                                       struct btrfs_delayed_node *node)
1008 {
1009         struct btrfs_delayed_item *curr, *prev;
1010         int ret = 0;
1011
1012 do_again:
1013         mutex_lock(&node->mutex);
1014         curr = __btrfs_first_delayed_deletion_item(node);
1015         if (!curr)
1016                 goto delete_fail;
1017
1018         ret = btrfs_search_slot(trans, root, &curr->key, path, -1, 1);
1019         if (ret < 0)
1020                 goto delete_fail;
1021         else if (ret > 0) {
1022                 /*
1023                  * can't find the item which the node points to, so this node
1024                  * is invalid, just drop it.
1025                  */
1026                 prev = curr;
1027                 curr = __btrfs_next_delayed_item(prev);
1028                 btrfs_release_delayed_item(prev);
1029                 ret = 0;
1030                 btrfs_release_path(path);
1031                 if (curr) {
1032                         mutex_unlock(&node->mutex);
1033                         goto do_again;
1034                 } else
1035                         goto delete_fail;
1036         }
1037
1038         btrfs_batch_delete_items(trans, root, path, curr);
1039         btrfs_release_path(path);
1040         mutex_unlock(&node->mutex);
1041         goto do_again;
1042
1043 delete_fail:
1044         btrfs_release_path(path);
1045         mutex_unlock(&node->mutex);
1046         return ret;
1047 }
1048
1049 static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
1050 {
1051         struct btrfs_delayed_root *delayed_root;
1052
1053         if (delayed_node && delayed_node->inode_dirty) {
1054                 BUG_ON(!delayed_node->root);
1055                 delayed_node->inode_dirty = 0;
1056                 delayed_node->count--;
1057
1058                 delayed_root = delayed_node->root->fs_info->delayed_root;
1059                 if (atomic_dec_return(&delayed_root->items) <
1060                     BTRFS_DELAYED_BACKGROUND &&
1061                     waitqueue_active(&delayed_root->wait))
1062                         wake_up(&delayed_root->wait);
1063         }
1064 }
1065
1066 static int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
1067                                       struct btrfs_root *root,
1068                                       struct btrfs_path *path,
1069                                       struct btrfs_delayed_node *node)
1070 {
1071         struct btrfs_key key;
1072         struct btrfs_inode_item *inode_item;
1073         struct extent_buffer *leaf;
1074         int ret;
1075
1076         mutex_lock(&node->mutex);
1077         if (!node->inode_dirty) {
1078                 mutex_unlock(&node->mutex);
1079                 return 0;
1080         }
1081
1082         key.objectid = node->inode_id;
1083         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
1084         key.offset = 0;
1085         ret = btrfs_lookup_inode(trans, root, path, &key, 1);
1086         if (ret > 0) {
1087                 btrfs_release_path(path);
1088                 mutex_unlock(&node->mutex);
1089                 return -ENOENT;
1090         } else if (ret < 0) {
1091                 mutex_unlock(&node->mutex);
1092                 return ret;
1093         }
1094
1095         btrfs_unlock_up_safe(path, 1);
1096         leaf = path->nodes[0];
1097         inode_item = btrfs_item_ptr(leaf, path->slots[0],
1098                                     struct btrfs_inode_item);
1099         write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
1100                             sizeof(struct btrfs_inode_item));
1101         btrfs_mark_buffer_dirty(leaf);
1102         btrfs_release_path(path);
1103
1104         btrfs_delayed_inode_release_metadata(root, node);
1105         btrfs_release_delayed_inode(node);
1106         mutex_unlock(&node->mutex);
1107
1108         return 0;
1109 }
1110
1111 /*
1112  * Called when committing the transaction.
1113  * Returns 0 on success.
1114  * Returns < 0 on error and returns with an aborted transaction with any
1115  * outstanding delayed items cleaned up.
1116  */
1117 static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans,
1118                                      struct btrfs_root *root, int nr)
1119 {
1120         struct btrfs_root *curr_root = root;
1121         struct btrfs_delayed_root *delayed_root;
1122         struct btrfs_delayed_node *curr_node, *prev_node;
1123         struct btrfs_path *path;
1124         struct btrfs_block_rsv *block_rsv;
1125         int ret = 0;
1126         bool count = (nr > 0);
1127
1128         if (trans->aborted)
1129                 return -EIO;
1130
1131         path = btrfs_alloc_path();
1132         if (!path)
1133                 return -ENOMEM;
1134         path->leave_spinning = 1;
1135
1136         block_rsv = trans->block_rsv;
1137         trans->block_rsv = &root->fs_info->delayed_block_rsv;
1138
1139         delayed_root = btrfs_get_delayed_root(root);
1140
1141         curr_node = btrfs_first_delayed_node(delayed_root);
1142         while (curr_node && (!count || (count && nr--))) {
1143                 curr_root = curr_node->root;
1144                 ret = btrfs_insert_delayed_items(trans, path, curr_root,
1145                                                  curr_node);
1146                 if (!ret)
1147                         ret = btrfs_delete_delayed_items(trans, path,
1148                                                 curr_root, curr_node);
1149                 if (!ret)
1150                         ret = btrfs_update_delayed_inode(trans, curr_root,
1151                                                 path, curr_node);
1152                 if (ret) {
1153                         btrfs_release_delayed_node(curr_node);
1154                         curr_node = NULL;
1155                         btrfs_abort_transaction(trans, root, ret);
1156                         break;
1157                 }
1158
1159                 prev_node = curr_node;
1160                 curr_node = btrfs_next_delayed_node(curr_node);
1161                 btrfs_release_delayed_node(prev_node);
1162         }
1163
1164         if (curr_node)
1165                 btrfs_release_delayed_node(curr_node);
1166         btrfs_free_path(path);
1167         trans->block_rsv = block_rsv;
1168
1169         return ret;
1170 }
1171
1172 int btrfs_run_delayed_items(struct btrfs_trans_handle *trans,
1173                             struct btrfs_root *root)
1174 {
1175         return __btrfs_run_delayed_items(trans, root, -1);
1176 }
1177
1178 int btrfs_run_delayed_items_nr(struct btrfs_trans_handle *trans,
1179                                struct btrfs_root *root, int nr)
1180 {
1181         return __btrfs_run_delayed_items(trans, root, nr);
1182 }
1183
1184 static int __btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1185                                               struct btrfs_delayed_node *node)
1186 {
1187         struct btrfs_path *path;
1188         struct btrfs_block_rsv *block_rsv;
1189         int ret;
1190
1191         path = btrfs_alloc_path();
1192         if (!path)
1193                 return -ENOMEM;
1194         path->leave_spinning = 1;
1195
1196         block_rsv = trans->block_rsv;
1197         trans->block_rsv = &node->root->fs_info->delayed_block_rsv;
1198
1199         ret = btrfs_insert_delayed_items(trans, path, node->root, node);
1200         if (!ret)
1201                 ret = btrfs_delete_delayed_items(trans, path, node->root, node);
1202         if (!ret)
1203                 ret = btrfs_update_delayed_inode(trans, node->root, path, node);
1204         btrfs_free_path(path);
1205
1206         trans->block_rsv = block_rsv;
1207         return ret;
1208 }
1209
1210 int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1211                                      struct inode *inode)
1212 {
1213         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1214         int ret;
1215
1216         if (!delayed_node)
1217                 return 0;
1218
1219         mutex_lock(&delayed_node->mutex);
1220         if (!delayed_node->count) {
1221                 mutex_unlock(&delayed_node->mutex);
1222                 btrfs_release_delayed_node(delayed_node);
1223                 return 0;
1224         }
1225         mutex_unlock(&delayed_node->mutex);
1226
1227         ret = __btrfs_commit_inode_delayed_items(trans, delayed_node);
1228         btrfs_release_delayed_node(delayed_node);
1229         return ret;
1230 }
1231
1232 void btrfs_remove_delayed_node(struct inode *inode)
1233 {
1234         struct btrfs_delayed_node *delayed_node;
1235
1236         delayed_node = ACCESS_ONCE(BTRFS_I(inode)->delayed_node);
1237         if (!delayed_node)
1238                 return;
1239
1240         BTRFS_I(inode)->delayed_node = NULL;
1241         btrfs_release_delayed_node(delayed_node);
1242 }
1243
1244 struct btrfs_async_delayed_node {
1245         struct btrfs_root *root;
1246         struct btrfs_delayed_node *delayed_node;
1247         struct btrfs_work work;
1248 };
1249
1250 static void btrfs_async_run_delayed_node_done(struct btrfs_work *work)
1251 {
1252         struct btrfs_async_delayed_node *async_node;
1253         struct btrfs_trans_handle *trans;
1254         struct btrfs_path *path;
1255         struct btrfs_delayed_node *delayed_node = NULL;
1256         struct btrfs_root *root;
1257         struct btrfs_block_rsv *block_rsv;
1258         unsigned long nr = 0;
1259         int need_requeue = 0;
1260         int ret;
1261
1262         async_node = container_of(work, struct btrfs_async_delayed_node, work);
1263
1264         path = btrfs_alloc_path();
1265         if (!path)
1266                 goto out;
1267         path->leave_spinning = 1;
1268
1269         delayed_node = async_node->delayed_node;
1270         root = delayed_node->root;
1271
1272         trans = btrfs_join_transaction(root);
1273         if (IS_ERR(trans))
1274                 goto free_path;
1275
1276         block_rsv = trans->block_rsv;
1277         trans->block_rsv = &root->fs_info->delayed_block_rsv;
1278
1279         ret = btrfs_insert_delayed_items(trans, path, root, delayed_node);
1280         if (!ret)
1281                 ret = btrfs_delete_delayed_items(trans, path, root,
1282                                                  delayed_node);
1283
1284         if (!ret)
1285                 btrfs_update_delayed_inode(trans, root, path, delayed_node);
1286
1287         /*
1288          * Maybe new delayed items have been inserted, so we need requeue
1289          * the work. Besides that, we must dequeue the empty delayed nodes
1290          * to avoid the race between delayed items balance and the worker.
1291          * The race like this:
1292          *      Task1                           Worker thread
1293          *                                      count == 0, needn't requeue
1294          *                                        also needn't insert the
1295          *                                        delayed node into prepare
1296          *                                        list again.
1297          *      add lots of delayed items
1298          *      queue the delayed node
1299          *        already in the list,
1300          *        and not in the prepare
1301          *        list, it means the delayed
1302          *        node is being dealt with
1303          *        by the worker.
1304          *      do delayed items balance
1305          *        the delayed node is being
1306          *        dealt with by the worker
1307          *        now, just wait.
1308          *                                      the worker goto idle.
1309          * Task1 will sleep until the transaction is commited.
1310          */
1311         mutex_lock(&delayed_node->mutex);
1312         if (delayed_node->count)
1313                 need_requeue = 1;
1314         else
1315                 btrfs_dequeue_delayed_node(root->fs_info->delayed_root,
1316                                            delayed_node);
1317         mutex_unlock(&delayed_node->mutex);
1318
1319         nr = trans->blocks_used;
1320
1321         trans->block_rsv = block_rsv;
1322         btrfs_end_transaction_dmeta(trans, root);
1323         __btrfs_btree_balance_dirty(root, nr);
1324 free_path:
1325         btrfs_free_path(path);
1326 out:
1327         if (need_requeue)
1328                 btrfs_requeue_work(&async_node->work);
1329         else {
1330                 btrfs_release_prepared_delayed_node(delayed_node);
1331                 kfree(async_node);
1332         }
1333 }
1334
1335 static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
1336                                      struct btrfs_root *root, int all)
1337 {
1338         struct btrfs_async_delayed_node *async_node;
1339         struct btrfs_delayed_node *curr;
1340         int count = 0;
1341
1342 again:
1343         curr = btrfs_first_prepared_delayed_node(delayed_root);
1344         if (!curr)
1345                 return 0;
1346
1347         async_node = kmalloc(sizeof(*async_node), GFP_NOFS);
1348         if (!async_node) {
1349                 btrfs_release_prepared_delayed_node(curr);
1350                 return -ENOMEM;
1351         }
1352
1353         async_node->root = root;
1354         async_node->delayed_node = curr;
1355
1356         async_node->work.func = btrfs_async_run_delayed_node_done;
1357         async_node->work.flags = 0;
1358
1359         btrfs_queue_worker(&root->fs_info->delayed_workers, &async_node->work);
1360         count++;
1361
1362         if (all || count < 4)
1363                 goto again;
1364
1365         return 0;
1366 }
1367
1368 void btrfs_assert_delayed_root_empty(struct btrfs_root *root)
1369 {
1370         struct btrfs_delayed_root *delayed_root;
1371         delayed_root = btrfs_get_delayed_root(root);
1372         WARN_ON(btrfs_first_delayed_node(delayed_root));
1373 }
1374
1375 void btrfs_balance_delayed_items(struct btrfs_root *root)
1376 {
1377         struct btrfs_delayed_root *delayed_root;
1378
1379         delayed_root = btrfs_get_delayed_root(root);
1380
1381         if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
1382                 return;
1383
1384         if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
1385                 int ret;
1386                 ret = btrfs_wq_run_delayed_node(delayed_root, root, 1);
1387                 if (ret)
1388                         return;
1389
1390                 wait_event_interruptible_timeout(
1391                                 delayed_root->wait,
1392                                 (atomic_read(&delayed_root->items) <
1393                                  BTRFS_DELAYED_BACKGROUND),
1394                                 HZ);
1395                 return;
1396         }
1397
1398         btrfs_wq_run_delayed_node(delayed_root, root, 0);
1399 }
1400
1401 /* Will return 0 or -ENOMEM */
1402 int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
1403                                    struct btrfs_root *root, const char *name,
1404                                    int name_len, struct inode *dir,
1405                                    struct btrfs_disk_key *disk_key, u8 type,
1406                                    u64 index)
1407 {
1408         struct btrfs_delayed_node *delayed_node;
1409         struct btrfs_delayed_item *delayed_item;
1410         struct btrfs_dir_item *dir_item;
1411         int ret;
1412
1413         delayed_node = btrfs_get_or_create_delayed_node(dir);
1414         if (IS_ERR(delayed_node))
1415                 return PTR_ERR(delayed_node);
1416
1417         delayed_item = btrfs_alloc_delayed_item(sizeof(*dir_item) + name_len);
1418         if (!delayed_item) {
1419                 ret = -ENOMEM;
1420                 goto release_node;
1421         }
1422
1423         delayed_item->key.objectid = btrfs_ino(dir);
1424         btrfs_set_key_type(&delayed_item->key, BTRFS_DIR_INDEX_KEY);
1425         delayed_item->key.offset = index;
1426
1427         dir_item = (struct btrfs_dir_item *)delayed_item->data;
1428         dir_item->location = *disk_key;
1429         dir_item->transid = cpu_to_le64(trans->transid);
1430         dir_item->data_len = 0;
1431         dir_item->name_len = cpu_to_le16(name_len);
1432         dir_item->type = type;
1433         memcpy((char *)(dir_item + 1), name, name_len);
1434
1435         ret = btrfs_delayed_item_reserve_metadata(trans, root, delayed_item);
1436         /*
1437          * we have reserved enough space when we start a new transaction,
1438          * so reserving metadata failure is impossible
1439          */
1440         BUG_ON(ret);
1441
1442
1443         mutex_lock(&delayed_node->mutex);
1444         ret = __btrfs_add_delayed_insertion_item(delayed_node, delayed_item);
1445         if (unlikely(ret)) {
1446                 printk(KERN_ERR "err add delayed dir index item(name: %s) into "
1447                                 "the insertion tree of the delayed node"
1448                                 "(root id: %llu, inode id: %llu, errno: %d)\n",
1449                                 name,
1450                                 (unsigned long long)delayed_node->root->objectid,
1451                                 (unsigned long long)delayed_node->inode_id,
1452                                 ret);
1453                 BUG();
1454         }
1455         mutex_unlock(&delayed_node->mutex);
1456
1457 release_node:
1458         btrfs_release_delayed_node(delayed_node);
1459         return ret;
1460 }
1461
1462 static int btrfs_delete_delayed_insertion_item(struct btrfs_root *root,
1463                                                struct btrfs_delayed_node *node,
1464                                                struct btrfs_key *key)
1465 {
1466         struct btrfs_delayed_item *item;
1467
1468         mutex_lock(&node->mutex);
1469         item = __btrfs_lookup_delayed_insertion_item(node, key);
1470         if (!item) {
1471                 mutex_unlock(&node->mutex);
1472                 return 1;
1473         }
1474
1475         btrfs_delayed_item_release_metadata(root, item);
1476         btrfs_release_delayed_item(item);
1477         mutex_unlock(&node->mutex);
1478         return 0;
1479 }
1480
1481 int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
1482                                    struct btrfs_root *root, struct inode *dir,
1483                                    u64 index)
1484 {
1485         struct btrfs_delayed_node *node;
1486         struct btrfs_delayed_item *item;
1487         struct btrfs_key item_key;
1488         int ret;
1489
1490         node = btrfs_get_or_create_delayed_node(dir);
1491         if (IS_ERR(node))
1492                 return PTR_ERR(node);
1493
1494         item_key.objectid = btrfs_ino(dir);
1495         btrfs_set_key_type(&item_key, BTRFS_DIR_INDEX_KEY);
1496         item_key.offset = index;
1497
1498         ret = btrfs_delete_delayed_insertion_item(root, node, &item_key);
1499         if (!ret)
1500                 goto end;
1501
1502         item = btrfs_alloc_delayed_item(0);
1503         if (!item) {
1504                 ret = -ENOMEM;
1505                 goto end;
1506         }
1507
1508         item->key = item_key;
1509
1510         ret = btrfs_delayed_item_reserve_metadata(trans, root, item);
1511         /*
1512          * we have reserved enough space when we start a new transaction,
1513          * so reserving metadata failure is impossible.
1514          */
1515         BUG_ON(ret);
1516
1517         mutex_lock(&node->mutex);
1518         ret = __btrfs_add_delayed_deletion_item(node, item);
1519         if (unlikely(ret)) {
1520                 printk(KERN_ERR "err add delayed dir index item(index: %llu) "
1521                                 "into the deletion tree of the delayed node"
1522                                 "(root id: %llu, inode id: %llu, errno: %d)\n",
1523                                 (unsigned long long)index,
1524                                 (unsigned long long)node->root->objectid,
1525                                 (unsigned long long)node->inode_id,
1526                                 ret);
1527                 BUG();
1528         }
1529         mutex_unlock(&node->mutex);
1530 end:
1531         btrfs_release_delayed_node(node);
1532         return ret;
1533 }
1534
1535 int btrfs_inode_delayed_dir_index_count(struct inode *inode)
1536 {
1537         struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1538
1539         if (!delayed_node)
1540                 return -ENOENT;
1541
1542         /*
1543          * Since we have held i_mutex of this directory, it is impossible that
1544          * a new directory index is added into the delayed node and index_cnt
1545          * is updated now. So we needn't lock the delayed node.
1546          */
1547         if (!delayed_node->index_cnt) {
1548                 btrfs_release_delayed_node(delayed_node);
1549                 return -EINVAL;
1550         }
1551
1552         BTRFS_I(inode)->index_cnt = delayed_node->index_cnt;
1553         btrfs_release_delayed_node(delayed_node);
1554         return 0;
1555 }
1556
1557 void btrfs_get_delayed_items(struct inode *inode, struct list_head *ins_list,
1558                              struct list_head *del_list)
1559 {
1560         struct btrfs_delayed_node *delayed_node;
1561         struct btrfs_delayed_item *item;
1562
1563         delayed_node = btrfs_get_delayed_node(inode);
1564         if (!delayed_node)
1565                 return;
1566
1567         mutex_lock(&delayed_node->mutex);
1568         item = __btrfs_first_delayed_insertion_item(delayed_node);
1569         while (item) {
1570                 atomic_inc(&item->refs);
1571                 list_add_tail(&item->readdir_list, ins_list);
1572                 item = __btrfs_next_delayed_item(item);
1573         }
1574
1575         item = __btrfs_first_delayed_deletion_item(delayed_node);
1576         while (item) {
1577                 atomic_inc(&item->refs);
1578                 list_add_tail(&item->readdir_list, del_list);
1579                 item = __btrfs_next_delayed_item(item);
1580         }
1581         mutex_unlock(&delayed_node->mutex);
1582         /*
1583          * This delayed node is still cached in the btrfs inode, so refs
1584          * must be > 1 now, and we needn't check it is going to be freed
1585          * or not.
1586          *
1587          * Besides that, this function is used to read dir, we do not
1588          * insert/delete delayed items in this period. So we also needn't
1589          * requeue or dequeue this delayed node.
1590          */
1591         atomic_dec(&delayed_node->refs);
1592 }
1593
1594 void btrfs_put_delayed_items(struct list_head *ins_list,
1595                              struct list_head *del_list)
1596 {
1597         struct btrfs_delayed_item *curr, *next;
1598
1599         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1600                 list_del(&curr->readdir_list);
1601                 if (atomic_dec_and_test(&curr->refs))
1602                         kfree(curr);
1603         }
1604
1605         list_for_each_entry_safe(curr, next, del_list, readdir_list) {
1606                 list_del(&curr->readdir_list);
1607                 if (atomic_dec_and_test(&curr->refs))
1608                         kfree(curr);
1609         }
1610 }
1611
1612 int btrfs_should_delete_dir_index(struct list_head *del_list,
1613                                   u64 index)
1614 {
1615         struct btrfs_delayed_item *curr, *next;
1616         int ret;
1617
1618         if (list_empty(del_list))
1619                 return 0;
1620
1621         list_for_each_entry_safe(curr, next, del_list, readdir_list) {
1622                 if (curr->key.offset > index)
1623                         break;
1624
1625                 list_del(&curr->readdir_list);
1626                 ret = (curr->key.offset == index);
1627
1628                 if (atomic_dec_and_test(&curr->refs))
1629                         kfree(curr);
1630
1631                 if (ret)
1632                         return 1;
1633                 else
1634                         continue;
1635         }
1636         return 0;
1637 }
1638
1639 /*
1640  * btrfs_readdir_delayed_dir_index - read dir info stored in the delayed tree
1641  *
1642  */
1643 int btrfs_readdir_delayed_dir_index(struct file *filp, void *dirent,
1644                                     filldir_t filldir,
1645                                     struct list_head *ins_list)
1646 {
1647         struct btrfs_dir_item *di;
1648         struct btrfs_delayed_item *curr, *next;
1649         struct btrfs_key location;
1650         char *name;
1651         int name_len;
1652         int over = 0;
1653         unsigned char d_type;
1654
1655         if (list_empty(ins_list))
1656                 return 0;
1657
1658         /*
1659          * Changing the data of the delayed item is impossible. So
1660          * we needn't lock them. And we have held i_mutex of the
1661          * directory, nobody can delete any directory indexes now.
1662          */
1663         list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1664                 list_del(&curr->readdir_list);
1665
1666                 if (curr->key.offset < filp->f_pos) {
1667                         if (atomic_dec_and_test(&curr->refs))
1668                                 kfree(curr);
1669                         continue;
1670                 }
1671
1672                 filp->f_pos = curr->key.offset;
1673
1674                 di = (struct btrfs_dir_item *)curr->data;
1675                 name = (char *)(di + 1);
1676                 name_len = le16_to_cpu(di->name_len);
1677
1678                 d_type = btrfs_filetype_table[di->type];
1679                 btrfs_disk_key_to_cpu(&location, &di->location);
1680
1681                 over = filldir(dirent, name, name_len, curr->key.offset,
1682                                location.objectid, d_type);
1683
1684                 if (atomic_dec_and_test(&curr->refs))
1685                         kfree(curr);
1686
1687                 if (over)
1688                         return 1;
1689         }
1690         return 0;
1691 }
1692
1693 BTRFS_SETGET_STACK_FUNCS(stack_inode_generation, struct btrfs_inode_item,
1694                          generation, 64);
1695 BTRFS_SETGET_STACK_FUNCS(stack_inode_sequence, struct btrfs_inode_item,
1696                          sequence, 64);
1697 BTRFS_SETGET_STACK_FUNCS(stack_inode_transid, struct btrfs_inode_item,
1698                          transid, 64);
1699 BTRFS_SETGET_STACK_FUNCS(stack_inode_size, struct btrfs_inode_item, size, 64);
1700 BTRFS_SETGET_STACK_FUNCS(stack_inode_nbytes, struct btrfs_inode_item,
1701                          nbytes, 64);
1702 BTRFS_SETGET_STACK_FUNCS(stack_inode_block_group, struct btrfs_inode_item,
1703                          block_group, 64);
1704 BTRFS_SETGET_STACK_FUNCS(stack_inode_nlink, struct btrfs_inode_item, nlink, 32);
1705 BTRFS_SETGET_STACK_FUNCS(stack_inode_uid, struct btrfs_inode_item, uid, 32);
1706 BTRFS_SETGET_STACK_FUNCS(stack_inode_gid, struct btrfs_inode_item, gid, 32);
1707 BTRFS_SETGET_STACK_FUNCS(stack_inode_mode, struct btrfs_inode_item, mode, 32);
1708 BTRFS_SETGET_STACK_FUNCS(stack_inode_rdev, struct btrfs_inode_item, rdev, 64);
1709 BTRFS_SETGET_STACK_FUNCS(stack_inode_flags, struct btrfs_inode_item, flags, 64);
1710
1711 BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
1712 BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec, nsec, 32);
1713
1714 static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
1715                                   struct btrfs_inode_item *inode_item,
1716                                   struct inode *inode)
1717 {
1718         btrfs_set_stack_inode_uid(inode_item, i_uid_read(inode));
1719         btrfs_set_stack_inode_gid(inode_item, i_gid_read(inode));
1720         btrfs_set_stack_inode_size(inode_item, BTRFS_I(inode)->disk_i_size);
1721         btrfs_set_stack_inode_mode(inode_item, inode->i_mode);
1722         btrfs_set_stack_inode_nlink(inode_item, inode->i_nlink);
1723         btrfs_set_stack_inode_nbytes(inode_item, inode_get_bytes(inode));
1724         btrfs_set_stack_inode_generation(inode_item,
1725                                          BTRFS_I(inode)->generation);
1726         btrfs_set_stack_inode_sequence(inode_item, inode->i_version);
1727         btrfs_set_stack_inode_transid(inode_item, trans->transid);
1728         btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
1729         btrfs_set_stack_inode_flags(inode_item, BTRFS_I(inode)->flags);
1730         btrfs_set_stack_inode_block_group(inode_item, 0);
1731
1732         btrfs_set_stack_timespec_sec(btrfs_inode_atime(inode_item),
1733                                      inode->i_atime.tv_sec);
1734         btrfs_set_stack_timespec_nsec(btrfs_inode_atime(inode_item),
1735                                       inode->i_atime.tv_nsec);
1736
1737         btrfs_set_stack_timespec_sec(btrfs_inode_mtime(inode_item),
1738                                      inode->i_mtime.tv_sec);
1739         btrfs_set_stack_timespec_nsec(btrfs_inode_mtime(inode_item),
1740                                       inode->i_mtime.tv_nsec);
1741
1742         btrfs_set_stack_timespec_sec(btrfs_inode_ctime(inode_item),
1743                                      inode->i_ctime.tv_sec);
1744         btrfs_set_stack_timespec_nsec(btrfs_inode_ctime(inode_item),
1745                                       inode->i_ctime.tv_nsec);
1746 }
1747
1748 int btrfs_fill_inode(struct inode *inode, u32 *rdev)
1749 {
1750         struct btrfs_delayed_node *delayed_node;
1751         struct btrfs_inode_item *inode_item;
1752         struct btrfs_timespec *tspec;
1753
1754         delayed_node = btrfs_get_delayed_node(inode);
1755         if (!delayed_node)
1756                 return -ENOENT;
1757
1758         mutex_lock(&delayed_node->mutex);
1759         if (!delayed_node->inode_dirty) {
1760                 mutex_unlock(&delayed_node->mutex);
1761                 btrfs_release_delayed_node(delayed_node);
1762                 return -ENOENT;
1763         }
1764
1765         inode_item = &delayed_node->inode_item;
1766
1767         i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
1768         i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
1769         btrfs_i_size_write(inode, btrfs_stack_inode_size(inode_item));
1770         inode->i_mode = btrfs_stack_inode_mode(inode_item);
1771         set_nlink(inode, btrfs_stack_inode_nlink(inode_item));
1772         inode_set_bytes(inode, btrfs_stack_inode_nbytes(inode_item));
1773         BTRFS_I(inode)->generation = btrfs_stack_inode_generation(inode_item);
1774         inode->i_version = btrfs_stack_inode_sequence(inode_item);
1775         inode->i_rdev = 0;
1776         *rdev = btrfs_stack_inode_rdev(inode_item);
1777         BTRFS_I(inode)->flags = btrfs_stack_inode_flags(inode_item);
1778
1779         tspec = btrfs_inode_atime(inode_item);
1780         inode->i_atime.tv_sec = btrfs_stack_timespec_sec(tspec);
1781         inode->i_atime.tv_nsec = btrfs_stack_timespec_nsec(tspec);
1782
1783         tspec = btrfs_inode_mtime(inode_item);
1784         inode->i_mtime.tv_sec = btrfs_stack_timespec_sec(tspec);
1785         inode->i_mtime.tv_nsec = btrfs_stack_timespec_nsec(tspec);
1786
1787         tspec = btrfs_inode_ctime(inode_item);
1788         inode->i_ctime.tv_sec = btrfs_stack_timespec_sec(tspec);
1789         inode->i_ctime.tv_nsec = btrfs_stack_timespec_nsec(tspec);
1790
1791         inode->i_generation = BTRFS_I(inode)->generation;
1792         BTRFS_I(inode)->index_cnt = (u64)-1;
1793
1794         mutex_unlock(&delayed_node->mutex);
1795         btrfs_release_delayed_node(delayed_node);
1796         return 0;
1797 }
1798
1799 int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
1800                                struct btrfs_root *root, struct inode *inode)
1801 {
1802         struct btrfs_delayed_node *delayed_node;
1803         int ret = 0;
1804
1805         delayed_node = btrfs_get_or_create_delayed_node(inode);
1806         if (IS_ERR(delayed_node))
1807                 return PTR_ERR(delayed_node);
1808
1809         mutex_lock(&delayed_node->mutex);
1810         if (delayed_node->inode_dirty) {
1811                 fill_stack_inode_item(trans, &delayed_node->inode_item, inode);
1812                 goto release_node;
1813         }
1814
1815         ret = btrfs_delayed_inode_reserve_metadata(trans, root, inode,
1816                                                    delayed_node);
1817         if (ret)
1818                 goto release_node;
1819
1820         fill_stack_inode_item(trans, &delayed_node->inode_item, inode);
1821         delayed_node->inode_dirty = 1;
1822         delayed_node->count++;
1823         atomic_inc(&root->fs_info->delayed_root->items);
1824 release_node:
1825         mutex_unlock(&delayed_node->mutex);
1826         btrfs_release_delayed_node(delayed_node);
1827         return ret;
1828 }
1829
1830 static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
1831 {
1832         struct btrfs_root *root = delayed_node->root;
1833         struct btrfs_delayed_item *curr_item, *prev_item;
1834
1835         mutex_lock(&delayed_node->mutex);
1836         curr_item = __btrfs_first_delayed_insertion_item(delayed_node);
1837         while (curr_item) {
1838                 btrfs_delayed_item_release_metadata(root, curr_item);
1839                 prev_item = curr_item;
1840                 curr_item = __btrfs_next_delayed_item(prev_item);
1841                 btrfs_release_delayed_item(prev_item);
1842         }
1843
1844         curr_item = __btrfs_first_delayed_deletion_item(delayed_node);
1845         while (curr_item) {
1846                 btrfs_delayed_item_release_metadata(root, curr_item);
1847                 prev_item = curr_item;
1848                 curr_item = __btrfs_next_delayed_item(prev_item);
1849                 btrfs_release_delayed_item(prev_item);
1850         }
1851
1852         if (delayed_node->inode_dirty) {
1853                 btrfs_delayed_inode_release_metadata(root, delayed_node);
1854                 btrfs_release_delayed_inode(delayed_node);
1855         }
1856         mutex_unlock(&delayed_node->mutex);
1857 }
1858
1859 void btrfs_kill_delayed_inode_items(struct inode *inode)
1860 {
1861         struct btrfs_delayed_node *delayed_node;
1862
1863         delayed_node = btrfs_get_delayed_node(inode);
1864         if (!delayed_node)
1865                 return;
1866
1867         __btrfs_kill_delayed_node(delayed_node);
1868         btrfs_release_delayed_node(delayed_node);
1869 }
1870
1871 void btrfs_kill_all_delayed_nodes(struct btrfs_root *root)
1872 {
1873         u64 inode_id = 0;
1874         struct btrfs_delayed_node *delayed_nodes[8];
1875         int i, n;
1876
1877         while (1) {
1878                 spin_lock(&root->inode_lock);
1879                 n = radix_tree_gang_lookup(&root->delayed_nodes_tree,
1880                                            (void **)delayed_nodes, inode_id,
1881                                            ARRAY_SIZE(delayed_nodes));
1882                 if (!n) {
1883                         spin_unlock(&root->inode_lock);
1884                         break;
1885                 }
1886
1887                 inode_id = delayed_nodes[n - 1]->inode_id + 1;
1888
1889                 for (i = 0; i < n; i++)
1890                         atomic_inc(&delayed_nodes[i]->refs);
1891                 spin_unlock(&root->inode_lock);
1892
1893                 for (i = 0; i < n; i++) {
1894                         __btrfs_kill_delayed_node(delayed_nodes[i]);
1895                         btrfs_release_delayed_node(delayed_nodes[i]);
1896                 }
1897         }
1898 }
1899
1900 void btrfs_destroy_delayed_inodes(struct btrfs_root *root)
1901 {
1902         struct btrfs_delayed_root *delayed_root;
1903         struct btrfs_delayed_node *curr_node, *prev_node;
1904
1905         delayed_root = btrfs_get_delayed_root(root);
1906
1907         curr_node = btrfs_first_delayed_node(delayed_root);
1908         while (curr_node) {
1909                 __btrfs_kill_delayed_node(curr_node);
1910
1911                 prev_node = curr_node;
1912                 curr_node = btrfs_next_delayed_node(curr_node);
1913                 btrfs_release_delayed_node(prev_node);
1914         }
1915 }
1916