fs/btrfs/free-space-cache.c

   1 /*
   2  * Copyright (C) 2008 Red Hat.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/pagemap.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/math64.h>
  23 #include <linux/ratelimit.h>
  24 #include "ctree.h"
  25 #include "free-space-cache.h"
  26 #include "transaction.h"
  27 #include "disk-io.h"
  28 #include "extent_io.h"
  29 #include "inode-map.h"
  30 #include "volumes.h"
  31
  32 #define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
  33 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
  34
  35 struct btrfs_trim_range {
  36         u64 start;
  37         u64 bytes;
  38         struct list_head list;
  39 };
  40
  41 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  42                            struct btrfs_free_space *info);
  43 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  44                               struct btrfs_free_space *info);
  45
  46 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  47                                                struct btrfs_path *path,
  48                                                u64 offset)
  49 {
  50         struct btrfs_key key;
  51         struct btrfs_key location;
  52         struct btrfs_disk_key disk_key;
  53         struct btrfs_free_space_header *header;
  54         struct extent_buffer *leaf;
  55         struct inode *inode = NULL;
  56         int ret;
  57
  58         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  59         key.offset = offset;
  60         key.type = 0;
  61
  62         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  63         if (ret < 0)
  64                 return ERR_PTR(ret);
  65         if (ret > 0) {
  66                 btrfs_release_path(path);
  67                 return ERR_PTR(-ENOENT);
  68         }
  69
  70         leaf = path->nodes[0];
  71         header = btrfs_item_ptr(leaf, path->slots[0],
  72                                 struct btrfs_free_space_header);
  73         btrfs_free_space_key(leaf, header, &disk_key);
  74         btrfs_disk_key_to_cpu(&location, &disk_key);
  75         btrfs_release_path(path);
  76
  77         inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
  78         if (!inode)
  79                 return ERR_PTR(-ENOENT);
  80         if (IS_ERR(inode))
  81                 return inode;
  82         if (is_bad_inode(inode)) {
  83                 iput(inode);
  84                 return ERR_PTR(-ENOENT);
  85         }
  86
  87         mapping_set_gfp_mask(inode->i_mapping,
  88                         mapping_gfp_mask(inode->i_mapping) &
  89                         ~(GFP_NOFS & ~__GFP_HIGHMEM));
  90
  91         return inode;
  92 }
  93
  94 struct inode *lookup_free_space_inode(struct btrfs_root *root,
  95                                       struct btrfs_block_group_cache
  96                                       *block_group, struct btrfs_path *path)
  97 {
  98         struct inode *inode = NULL;
  99         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 100
 101         spin_lock(&block_group->lock);
 102         if (block_group->inode)
 103                 inode = igrab(block_group->inode);
 104         spin_unlock(&block_group->lock);
 105         if (inode)
 106                 return inode;
 107
 108         inode = __lookup_free_space_inode(root, path,
 109                                           block_group->key.objectid);
 110         if (IS_ERR(inode))
 111                 return inode;
 112
 113         spin_lock(&block_group->lock);
 114         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 115                 btrfs_info(root->fs_info,
 116                         "Old style space inode found, converting.");
 117                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 118                         BTRFS_INODE_NODATACOW;
 119                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 120         }
 121
 122         if (!block_group->iref) {
 123                 block_group->inode = igrab(inode);
 124                 block_group->iref = 1;
 125         }
 126         spin_unlock(&block_group->lock);
 127
 128         return inode;
 129 }
 130
 131 static int __create_free_space_inode(struct btrfs_root *root,
 132                                      struct btrfs_trans_handle *trans,
 133                                      struct btrfs_path *path,
 134                                      u64 ino, u64 offset)
 135 {
 136         struct btrfs_key key;
 137         struct btrfs_disk_key disk_key;
 138         struct btrfs_free_space_header *header;
 139         struct btrfs_inode_item *inode_item;
 140         struct extent_buffer *leaf;
 141         u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 142         int ret;
 143
 144         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 145         if (ret)
 146                 return ret;
 147
 148         /* We inline crc's for the free disk space cache */
 149         if (ino != BTRFS_FREE_INO_OBJECTID)
 150                 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 151
 152         leaf = path->nodes[0];
 153         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 154                                     struct btrfs_inode_item);
 155         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 156         memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
 157                              sizeof(*inode_item));
 158         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 159         btrfs_set_inode_size(leaf, inode_item, 0);
 160         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 161         btrfs_set_inode_uid(leaf, inode_item, 0);
 162         btrfs_set_inode_gid(leaf, inode_item, 0);
 163         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 164         btrfs_set_inode_flags(leaf, inode_item, flags);
 165         btrfs_set_inode_nlink(leaf, inode_item, 1);
 166         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 167         btrfs_set_inode_block_group(leaf, inode_item, offset);
 168         btrfs_mark_buffer_dirty(leaf);
 169         btrfs_release_path(path);
 170
 171         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 172         key.offset = offset;
 173         key.type = 0;
 174         ret = btrfs_insert_empty_item(trans, root, path, &key,
 175                                       sizeof(struct btrfs_free_space_header));
 176         if (ret < 0) {
 177                 btrfs_release_path(path);
 178                 return ret;
 179         }
 180
 181         leaf = path->nodes[0];
 182         header = btrfs_item_ptr(leaf, path->slots[0],
 183                                 struct btrfs_free_space_header);
 184         memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
 185         btrfs_set_free_space_key(leaf, header, &disk_key);
 186         btrfs_mark_buffer_dirty(leaf);
 187         btrfs_release_path(path);
 188
 189         return 0;
 190 }
 191
 192 int create_free_space_inode(struct btrfs_root *root,
 193                             struct btrfs_trans_handle *trans,
 194                             struct btrfs_block_group_cache *block_group,
 195                             struct btrfs_path *path)
 196 {
 197         int ret;
 198         u64 ino;
 199
 200         ret = btrfs_find_free_objectid(root, &ino);
 201         if (ret < 0)
 202                 return ret;
 203
 204         return __create_free_space_inode(root, trans, path, ino,
 205                                          block_group->key.objectid);
 206 }
 207
 208 int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
 209                                        struct btrfs_block_rsv *rsv)
 210 {
 211         u64 needed_bytes;
 212         int ret;
 213
 214         /* 1 for slack space, 1 for updating the inode */
 215         needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
 216                 btrfs_calc_trans_metadata_size(root, 1);
 217
 218         spin_lock(&rsv->lock);
 219         if (rsv->reserved < needed_bytes)
 220                 ret = -ENOSPC;
 221         else
 222                 ret = 0;
 223         spin_unlock(&rsv->lock);
 224         return ret;
 225 }
 226
 227 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
 228                                     struct btrfs_trans_handle *trans,
 229                                     struct btrfs_block_group_cache *block_group,
 230                                     struct inode *inode)
 231 {
 232         int ret = 0;
 233         struct btrfs_path *path = btrfs_alloc_path();
 234
 235         if (!path) {
 236                 ret = -ENOMEM;
 237                 goto fail;
 238         }
 239
 240         if (block_group) {
 241                 mutex_lock(&trans->transaction->cache_write_mutex);
 242                 if (!list_empty(&block_group->io_list)) {
 243                         list_del_init(&block_group->io_list);
 244
 245                         btrfs_wait_cache_io(root, trans, block_group,
 246                                             &block_group->io_ctl, path,
 247                                             block_group->key.objectid);
 248                         btrfs_put_block_group(block_group);
 249                 }
 250
 251                 /*
 252                  * now that we've truncated the cache away, its no longer
 253                  * setup or written
 254                  */
 255                 spin_lock(&block_group->lock);
 256                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 257                 spin_unlock(&block_group->lock);
 258         }
 259         btrfs_free_path(path);
 260
 261         btrfs_i_size_write(inode, 0);
 262         truncate_pagecache(inode, 0);
 263
 264         /*
 265          * We don't need an orphan item because truncating the free space cache
 266          * will never be split across transactions.
 267          * We don't need to check for -EAGAIN because we're a free space
 268          * cache inode
 269          */
 270         ret = btrfs_truncate_inode_items(trans, root, inode,
 271                                          0, BTRFS_EXTENT_DATA_KEY);
 272         if (ret) {
 273                 mutex_unlock(&trans->transaction->cache_write_mutex);
 274                 btrfs_abort_transaction(trans, root, ret);
 275                 return ret;
 276         }
 277
 278         ret = btrfs_update_inode(trans, root, inode);
 279
 280         if (block_group)
 281                 mutex_unlock(&trans->transaction->cache_write_mutex);
 282
 283 fail:
 284         if (ret)
 285                 btrfs_abort_transaction(trans, root, ret);
 286
 287         return ret;
 288 }
 289
 290 static int readahead_cache(struct inode *inode)
 291 {
 292         struct file_ra_state *ra;
 293         unsigned long last_index;
 294
 295         ra = kzalloc(sizeof(*ra), GFP_NOFS);
 296         if (!ra)
 297                 return -ENOMEM;
 298
 299         file_ra_state_init(ra, inode->i_mapping);
 300         last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
 301
 302         page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 303
 304         kfree(ra);
 305
 306         return 0;
 307 }
 308
 309 static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 310                        struct btrfs_root *root, int write)
 311 {
 312         int num_pages;
 313         int check_crcs = 0;
 314
 315         num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
 316
 317         if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
 318                 check_crcs = 1;
 319
 320         /* Make sure we can fit our crcs into the first page */
 321         if (write && check_crcs &&
 322             (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
 323                 return -ENOSPC;
 324
 325         memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
 326
 327         io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
 328         if (!io_ctl->pages)
 329                 return -ENOMEM;
 330
 331         io_ctl->num_pages = num_pages;
 332         io_ctl->root = root;
 333         io_ctl->check_crcs = check_crcs;
 334         io_ctl->inode = inode;
 335
 336         return 0;
 337 }
 338
 339 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
 340 {
 341         kfree(io_ctl->pages);
 342         io_ctl->pages = NULL;
 343 }
 344
 345 static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
 346 {
 347         if (io_ctl->cur) {
 348                 io_ctl->cur = NULL;
 349                 io_ctl->orig = NULL;
 350         }
 351 }
 352
 353 static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
 354 {
 355         ASSERT(io_ctl->index < io_ctl->num_pages);
 356         io_ctl->page = io_ctl->pages[io_ctl->index++];
 357         io_ctl->cur = page_address(io_ctl->page);
 358         io_ctl->orig = io_ctl->cur;
 359         io_ctl->size = PAGE_CACHE_SIZE;
 360         if (clear)
 361                 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
 362 }
 363
 364 static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
 365 {
 366         int i;
 367
 368         io_ctl_unmap_page(io_ctl);
 369
 370         for (i = 0; i < io_ctl->num_pages; i++) {
 371                 if (io_ctl->pages[i]) {
 372                         ClearPageChecked(io_ctl->pages[i]);
 373                         unlock_page(io_ctl->pages[i]);
 374                         page_cache_release(io_ctl->pages[i]);
 375                 }
 376         }
 377 }
 378
 379 static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 380                                 int uptodate)
 381 {
 382         struct page *page;
 383         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 384         int i;
 385
 386         for (i = 0; i < io_ctl->num_pages; i++) {
 387                 page = find_or_create_page(inode->i_mapping, i, mask);
 388                 if (!page) {
 389                         io_ctl_drop_pages(io_ctl);
 390                         return -ENOMEM;
 391                 }
 392                 io_ctl->pages[i] = page;
 393                 if (uptodate && !PageUptodate(page)) {
 394                         btrfs_readpage(NULL, page);
 395                         lock_page(page);
 396                         if (!PageUptodate(page)) {
 397                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 398                                            "error reading free space cache");
 399                                 io_ctl_drop_pages(io_ctl);
 400                                 return -EIO;
 401                         }
 402                 }
 403         }
 404
 405         for (i = 0; i < io_ctl->num_pages; i++) {
 406                 clear_page_dirty_for_io(io_ctl->pages[i]);
 407                 set_page_extent_mapped(io_ctl->pages[i]);
 408         }
 409
 410         return 0;
 411 }
 412
 413 static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 414 {
 415         __le64 *val;
 416
 417         io_ctl_map_page(io_ctl, 1);
 418
 419         /*
 420          * Skip the csum areas.  If we don't check crcs then we just have a
 421          * 64bit chunk at the front of the first page.
 422          */
 423         if (io_ctl->check_crcs) {
 424                 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 425                 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 426         } else {
 427                 io_ctl->cur += sizeof(u64);
 428                 io_ctl->size -= sizeof(u64) * 2;
 429         }
 430
 431         val = io_ctl->cur;
 432         *val = cpu_to_le64(generation);
 433         io_ctl->cur += sizeof(u64);
 434 }
 435
 436 static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 437 {
 438         __le64 *gen;
 439
 440         /*
 441          * Skip the crc area.  If we don't check crcs then we just have a 64bit
 442          * chunk at the front of the first page.
 443          */
 444         if (io_ctl->check_crcs) {
 445                 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 446                 io_ctl->size -= sizeof(u64) +
 447                         (sizeof(u32) * io_ctl->num_pages);
 448         } else {
 449                 io_ctl->cur += sizeof(u64);
 450                 io_ctl->size -= sizeof(u64) * 2;
 451         }
 452
 453         gen = io_ctl->cur;
 454         if (le64_to_cpu(*gen) != generation) {
 455                 printk_ratelimited(KERN_ERR "BTRFS: space cache generation "
 456                                    "(%Lu) does not match inode (%Lu)\n", *gen,
 457                                    generation);
 458                 io_ctl_unmap_page(io_ctl);
 459                 return -EIO;
 460         }
 461         io_ctl->cur += sizeof(u64);
 462         return 0;
 463 }
 464
 465 static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
 466 {
 467         u32 *tmp;
 468         u32 crc = ~(u32)0;
 469         unsigned offset = 0;
 470
 471         if (!io_ctl->check_crcs) {
 472                 io_ctl_unmap_page(io_ctl);
 473                 return;
 474         }
 475
 476         if (index == 0)
 477                 offset = sizeof(u32) * io_ctl->num_pages;
 478
 479         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 480                               PAGE_CACHE_SIZE - offset);
 481         btrfs_csum_final(crc, (char *)&crc);
 482         io_ctl_unmap_page(io_ctl);
 483         tmp = page_address(io_ctl->pages[0]);
 484         tmp += index;
 485         *tmp = crc;
 486 }
 487
 488 static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
 489 {
 490         u32 *tmp, val;
 491         u32 crc = ~(u32)0;
 492         unsigned offset = 0;
 493
 494         if (!io_ctl->check_crcs) {
 495                 io_ctl_map_page(io_ctl, 0);
 496                 return 0;
 497         }
 498
 499         if (index == 0)
 500                 offset = sizeof(u32) * io_ctl->num_pages;
 501
 502         tmp = page_address(io_ctl->pages[0]);
 503         tmp += index;
 504         val = *tmp;
 505
 506         io_ctl_map_page(io_ctl, 0);
 507         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 508                               PAGE_CACHE_SIZE - offset);
 509         btrfs_csum_final(crc, (char *)&crc);
 510         if (val != crc) {
 511                 printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free "
 512                                    "space cache\n");
 513                 io_ctl_unmap_page(io_ctl);
 514                 return -EIO;
 515         }
 516
 517         return 0;
 518 }
 519
 520 static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
 521                             void *bitmap)
 522 {
 523         struct btrfs_free_space_entry *entry;
 524
 525         if (!io_ctl->cur)
 526                 return -ENOSPC;
 527
 528         entry = io_ctl->cur;
 529         entry->offset = cpu_to_le64(offset);
 530         entry->bytes = cpu_to_le64(bytes);
 531         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 532                 BTRFS_FREE_SPACE_EXTENT;
 533         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 534         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 535
 536         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 537                 return 0;
 538
 539         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 540
 541         /* No more pages to map */
 542         if (io_ctl->index >= io_ctl->num_pages)
 543                 return 0;
 544
 545         /* map the next page */
 546         io_ctl_map_page(io_ctl, 1);
 547         return 0;
 548 }
 549
 550 static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
 551 {
 552         if (!io_ctl->cur)
 553                 return -ENOSPC;
 554
 555         /*
 556          * If we aren't at the start of the current page, unmap this one and
 557          * map the next one if there is any left.
 558          */
 559         if (io_ctl->cur != io_ctl->orig) {
 560                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 561                 if (io_ctl->index >= io_ctl->num_pages)
 562                         return -ENOSPC;
 563                 io_ctl_map_page(io_ctl, 0);
 564         }
 565
 566         memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
 567         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 568         if (io_ctl->index < io_ctl->num_pages)
 569                 io_ctl_map_page(io_ctl, 0);
 570         return 0;
 571 }
 572
 573 static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
 574 {
 575         /*
 576          * If we're not on the boundary we know we've modified the page and we
 577          * need to crc the page.
 578          */
 579         if (io_ctl->cur != io_ctl->orig)
 580                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 581         else
 582                 io_ctl_unmap_page(io_ctl);
 583
 584         while (io_ctl->index < io_ctl->num_pages) {
 585                 io_ctl_map_page(io_ctl, 1);
 586                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 587         }
 588 }
 589
 590 static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
 591                             struct btrfs_free_space *entry, u8 *type)
 592 {
 593         struct btrfs_free_space_entry *e;
 594         int ret;
 595
 596         if (!io_ctl->cur) {
 597                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 598                 if (ret)
 599                         return ret;
 600         }
 601
 602         e = io_ctl->cur;
 603         entry->offset = le64_to_cpu(e->offset);
 604         entry->bytes = le64_to_cpu(e->bytes);
 605         *type = e->type;
 606         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 607         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 608
 609         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 610                 return 0;
 611
 612         io_ctl_unmap_page(io_ctl);
 613
 614         return 0;
 615 }
 616
 617 static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
 618                               struct btrfs_free_space *entry)
 619 {
 620         int ret;
 621
 622         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 623         if (ret)
 624                 return ret;
 625
 626         memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
 627         io_ctl_unmap_page(io_ctl);
 628
 629         return 0;
 630 }
 631
 632 /*
 633  * Since we attach pinned extents after the fact we can have contiguous sections
 634  * of free space that are split up in entries.  This poses a problem with the
 635  * tree logging stuff since it could have allocated across what appears to be 2
 636  * entries since we would have merged the entries when adding the pinned extents
 637  * back to the free space cache.  So run through the space cache that we just
 638  * loaded and merge contiguous entries.  This will make the log replay stuff not
 639  * blow up and it will make for nicer allocator behavior.
 640  */
 641 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
 642 {
 643         struct btrfs_free_space *e, *prev = NULL;
 644         struct rb_node *n;
 645
 646 again:
 647         spin_lock(&ctl->tree_lock);
 648         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 649                 e = rb_entry(n, struct btrfs_free_space, offset_index);
 650                 if (!prev)
 651                         goto next;
 652                 if (e->bitmap || prev->bitmap)
 653                         goto next;
 654                 if (prev->offset + prev->bytes == e->offset) {
 655                         unlink_free_space(ctl, prev);
 656                         unlink_free_space(ctl, e);
 657                         prev->bytes += e->bytes;
 658                         kmem_cache_free(btrfs_free_space_cachep, e);
 659                         link_free_space(ctl, prev);
 660                         prev = NULL;
 661                         spin_unlock(&ctl->tree_lock);
 662                         goto again;
 663                 }
 664 next:
 665                 prev = e;
 666         }
 667         spin_unlock(&ctl->tree_lock);
 668 }
 669
 670 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 671                                    struct btrfs_free_space_ctl *ctl,
 672                                    struct btrfs_path *path, u64 offset)
 673 {
 674         struct btrfs_free_space_header *header;
 675         struct extent_buffer *leaf;
 676         struct btrfs_io_ctl io_ctl;
 677         struct btrfs_key key;
 678         struct btrfs_free_space *e, *n;
 679         LIST_HEAD(bitmaps);
 680         u64 num_entries;
 681         u64 num_bitmaps;
 682         u64 generation;
 683         u8 type;
 684         int ret = 0;
 685
 686         /* Nothing in the space cache, goodbye */
 687         if (!i_size_read(inode))
 688                 return 0;
 689
 690         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 691         key.offset = offset;
 692         key.type = 0;
 693
 694         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 695         if (ret < 0)
 696                 return 0;
 697         else if (ret > 0) {
 698                 btrfs_release_path(path);
 699                 return 0;
 700         }
 701
 702         ret = -1;
 703
 704         leaf = path->nodes[0];
 705         header = btrfs_item_ptr(leaf, path->slots[0],
 706                                 struct btrfs_free_space_header);
 707         num_entries = btrfs_free_space_entries(leaf, header);
 708         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 709         generation = btrfs_free_space_generation(leaf, header);
 710         btrfs_release_path(path);
 711
 712         if (!BTRFS_I(inode)->generation) {
 713                 btrfs_info(root->fs_info,
 714                            "The free space cache file (%llu) is invalid. skip it\n",
 715                            offset);
 716                 return 0;
 717         }
 718
 719         if (BTRFS_I(inode)->generation != generation) {
 720                 btrfs_err(root->fs_info,
 721                         "free space inode generation (%llu) "
 722                         "did not match free space cache generation (%llu)",
 723                         BTRFS_I(inode)->generation, generation);
 724                 return 0;
 725         }
 726
 727         if (!num_entries)
 728                 return 0;
 729
 730         ret = io_ctl_init(&io_ctl, inode, root, 0);
 731         if (ret)
 732                 return ret;
 733
 734         ret = readahead_cache(inode);
 735         if (ret)
 736                 goto out;
 737
 738         ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
 739         if (ret)
 740                 goto out;
 741
 742         ret = io_ctl_check_crc(&io_ctl, 0);
 743         if (ret)
 744                 goto free_cache;
 745
 746         ret = io_ctl_check_generation(&io_ctl, generation);
 747         if (ret)
 748                 goto free_cache;
 749
 750         while (num_entries) {
 751                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
 752                                       GFP_NOFS);
 753                 if (!e)
 754                         goto free_cache;
 755
 756                 ret = io_ctl_read_entry(&io_ctl, e, &type);
 757                 if (ret) {
 758                         kmem_cache_free(btrfs_free_space_cachep, e);
 759                         goto free_cache;
 760                 }
 761
 762                 if (!e->bytes) {
 763                         kmem_cache_free(btrfs_free_space_cachep, e);
 764                         goto free_cache;
 765                 }
 766
 767                 if (type == BTRFS_FREE_SPACE_EXTENT) {
 768                         spin_lock(&ctl->tree_lock);
 769                         ret = link_free_space(ctl, e);
 770                         spin_unlock(&ctl->tree_lock);
 771                         if (ret) {
 772                                 btrfs_err(root->fs_info,
 773                                         "Duplicate entries in free space cache, dumping");
 774                                 kmem_cache_free(btrfs_free_space_cachep, e);
 775                                 goto free_cache;
 776                         }
 777                 } else {
 778                         ASSERT(num_bitmaps);
 779                         num_bitmaps--;
 780                         e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 781                         if (!e->bitmap) {
 782                                 kmem_cache_free(
 783                                         btrfs_free_space_cachep, e);
 784                                 goto free_cache;
 785                         }
 786                         spin_lock(&ctl->tree_lock);
 787                         ret = link_free_space(ctl, e);
 788                         ctl->total_bitmaps++;
 789                         ctl->op->recalc_thresholds(ctl);
 790                         spin_unlock(&ctl->tree_lock);
 791                         if (ret) {
 792                                 btrfs_err(root->fs_info,
 793                                         "Duplicate entries in free space cache, dumping");
 794                                 kmem_cache_free(btrfs_free_space_cachep, e);
 795                                 goto free_cache;
 796                         }
 797                         list_add_tail(&e->list, &bitmaps);
 798                 }
 799
 800                 num_entries--;
 801         }
 802
 803         io_ctl_unmap_page(&io_ctl);
 804
 805         /*
 806          * We add the bitmaps at the end of the entries in order that
 807          * the bitmap entries are added to the cache.
 808          */
 809         list_for_each_entry_safe(e, n, &bitmaps, list) {
 810                 list_del_init(&e->list);
 811                 ret = io_ctl_read_bitmap(&io_ctl, e);
 812                 if (ret)
 813                         goto free_cache;
 814         }
 815
 816         io_ctl_drop_pages(&io_ctl);
 817         merge_space_tree(ctl);
 818         ret = 1;
 819 out:
 820         io_ctl_free(&io_ctl);
 821         return ret;
 822 free_cache:
 823         io_ctl_drop_pages(&io_ctl);
 824         __btrfs_remove_free_space_cache(ctl);
 825         goto out;
 826 }
 827
 828 int load_free_space_cache(struct btrfs_fs_info *fs_info,
 829                           struct btrfs_block_group_cache *block_group)
 830 {
 831         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 832         struct btrfs_root *root = fs_info->tree_root;
 833         struct inode *inode;
 834         struct btrfs_path *path;
 835         int ret = 0;
 836         bool matched;
 837         u64 used = btrfs_block_group_used(&block_group->item);
 838
 839         /*
 840          * If this block group has been marked to be cleared for one reason or
 841          * another then we can't trust the on disk cache, so just return.
 842          */
 843         spin_lock(&block_group->lock);
 844         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 845                 spin_unlock(&block_group->lock);
 846                 return 0;
 847         }
 848         spin_unlock(&block_group->lock);
 849
 850         path = btrfs_alloc_path();
 851         if (!path)
 852                 return 0;
 853         path->search_commit_root = 1;
 854         path->skip_locking = 1;
 855
 856         inode = lookup_free_space_inode(root, block_group, path);
 857         if (IS_ERR(inode)) {
 858                 btrfs_free_path(path);
 859                 return 0;
 860         }
 861
 862         /* We may have converted the inode and made the cache invalid. */
 863         spin_lock(&block_group->lock);
 864         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 865                 spin_unlock(&block_group->lock);
 866                 btrfs_free_path(path);
 867                 goto out;
 868         }
 869         spin_unlock(&block_group->lock);
 870
 871         ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 872                                       path, block_group->key.objectid);
 873         btrfs_free_path(path);
 874         if (ret <= 0)
 875                 goto out;
 876
 877         spin_lock(&ctl->tree_lock);
 878         matched = (ctl->free_space == (block_group->key.offset - used -
 879                                        block_group->bytes_super));
 880         spin_unlock(&ctl->tree_lock);
 881
 882         if (!matched) {
 883                 __btrfs_remove_free_space_cache(ctl);
 884                 btrfs_warn(fs_info, "block group %llu has wrong amount of free space",
 885                         block_group->key.objectid);
 886                 ret = -1;
 887         }
 888 out:
 889         if (ret < 0) {
 890                 /* This cache is bogus, make sure it gets cleared */
 891                 spin_lock(&block_group->lock);
 892                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 893                 spin_unlock(&block_group->lock);
 894                 ret = 0;
 895
 896                 btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now",
 897                         block_group->key.objectid);
 898         }
 899
 900         iput(inode);
 901         return ret;
 902 }
 903
 904 static noinline_for_stack
 905 int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
 906                               struct btrfs_free_space_ctl *ctl,
 907                               struct btrfs_block_group_cache *block_group,
 908                               int *entries, int *bitmaps,
 909                               struct list_head *bitmap_list)
 910 {
 911         int ret;
 912         struct btrfs_free_cluster *cluster = NULL;
 913         struct btrfs_free_cluster *cluster_locked = NULL;
 914         struct rb_node *node = rb_first(&ctl->free_space_offset);
 915         struct btrfs_trim_range *trim_entry;
 916
 917         /* Get the cluster for this block_group if it exists */
 918         if (block_group && !list_empty(&block_group->cluster_list)) {
 919                 cluster = list_entry(block_group->cluster_list.next,
 920                                      struct btrfs_free_cluster,
 921                                      block_group_list);
 922         }
 923
 924         if (!node && cluster) {
 925                 cluster_locked = cluster;
 926                 spin_lock(&cluster_locked->lock);
 927                 node = rb_first(&cluster->root);
 928                 cluster = NULL;
 929         }
 930
 931         /* Write out the extent entries */
 932         while (node) {
 933                 struct btrfs_free_space *e;
 934
 935                 e = rb_entry(node, struct btrfs_free_space, offset_index);
 936                 *entries += 1;
 937
 938                 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
 939                                        e->bitmap);
 940                 if (ret)
 941                         goto fail;
 942
 943                 if (e->bitmap) {
 944                         list_add_tail(&e->list, bitmap_list);
 945                         *bitmaps += 1;
 946                 }
 947                 node = rb_next(node);
 948                 if (!node && cluster) {
 949                         node = rb_first(&cluster->root);
 950                         cluster_locked = cluster;
 951                         spin_lock(&cluster_locked->lock);
 952                         cluster = NULL;
 953                 }
 954         }
 955         if (cluster_locked) {
 956                 spin_unlock(&cluster_locked->lock);
 957                 cluster_locked = NULL;
 958         }
 959
 960         /*
 961          * Make sure we don't miss any range that was removed from our rbtree
 962          * because trimming is running. Otherwise after a umount+mount (or crash
 963          * after committing the transaction) we would leak free space and get
 964          * an inconsistent free space cache report from fsck.
 965          */
 966         list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
 967                 ret = io_ctl_add_entry(io_ctl, trim_entry->start,
 968                                        trim_entry->bytes, NULL);
 969                 if (ret)
 970                         goto fail;
 971                 *entries += 1;
 972         }
 973
 974         return 0;
 975 fail:
 976         if (cluster_locked)
 977                 spin_unlock(&cluster_locked->lock);
 978         return -ENOSPC;
 979 }
 980
 981 static noinline_for_stack int
 982 update_cache_item(struct btrfs_trans_handle *trans,
 983                   struct btrfs_root *root,
 984                   struct inode *inode,
 985                   struct btrfs_path *path, u64 offset,
 986                   int entries, int bitmaps)
 987 {
 988         struct btrfs_key key;
 989         struct btrfs_free_space_header *header;
 990         struct extent_buffer *leaf;
 991         int ret;
 992
 993         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 994         key.offset = offset;
 995         key.type = 0;
 996
 997         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 998         if (ret < 0) {
 999                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1000                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1001                                  GFP_NOFS);
1002                 goto fail;
1003         }
1004         leaf = path->nodes[0];
1005         if (ret > 0) {
1006                 struct btrfs_key found_key;
1007                 ASSERT(path->slots[0]);
1008                 path->slots[0]--;
1009                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1010                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1011                     found_key.offset != offset) {
1012                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1013                                          inode->i_size - 1,
1014                                          EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1015                                          NULL, GFP_NOFS);
1016                         btrfs_release_path(path);
1017                         goto fail;
1018                 }
1019         }
1020
1021         BTRFS_I(inode)->generation = trans->transid;
1022         header = btrfs_item_ptr(leaf, path->slots[0],
1023                                 struct btrfs_free_space_header);
1024         btrfs_set_free_space_entries(leaf, header, entries);
1025         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1026         btrfs_set_free_space_generation(leaf, header, trans->transid);
1027         btrfs_mark_buffer_dirty(leaf);
1028         btrfs_release_path(path);
1029
1030         return 0;
1031
1032 fail:
1033         return -1;
1034 }
1035
1036 static noinline_for_stack int
1037 write_pinned_extent_entries(struct btrfs_root *root,
1038                             struct btrfs_block_group_cache *block_group,
1039                             struct btrfs_io_ctl *io_ctl,
1040                             int *entries)
1041 {
1042         u64 start, extent_start, extent_end, len;
1043         struct extent_io_tree *unpin = NULL;
1044         int ret;
1045
1046         if (!block_group)
1047                 return 0;
1048
1049         /*
1050          * We want to add any pinned extents to our free space cache
1051          * so we don't leak the space
1052          *
1053          * We shouldn't have switched the pinned extents yet so this is the
1054          * right one
1055          */
1056         unpin = root->fs_info->pinned_extents;
1057
1058         start = block_group->key.objectid;
1059
1060         while (start < block_group->key.objectid + block_group->key.offset) {
1061                 ret = find_first_extent_bit(unpin, start,
1062                                             &extent_start, &extent_end,
1063                                             EXTENT_DIRTY, NULL);
1064                 if (ret)
1065                         return 0;
1066
1067                 /* This pinned extent is out of our range */
1068                 if (extent_start >= block_group->key.objectid +
1069                     block_group->key.offset)
1070                         return 0;
1071
1072                 extent_start = max(extent_start, start);
1073                 extent_end = min(block_group->key.objectid +
1074                                  block_group->key.offset, extent_end + 1);
1075                 len = extent_end - extent_start;
1076
1077                 *entries += 1;
1078                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1079                 if (ret)
1080                         return -ENOSPC;
1081
1082                 start = extent_end;
1083         }
1084
1085         return 0;
1086 }
1087
1088 static noinline_for_stack int
1089 write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1090 {
1091         struct list_head *pos, *n;
1092         int ret;
1093
1094         /* Write out the bitmaps */
1095         list_for_each_safe(pos, n, bitmap_list) {
1096                 struct btrfs_free_space *entry =
1097                         list_entry(pos, struct btrfs_free_space, list);
1098
1099                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1100                 if (ret)
1101                         return -ENOSPC;
1102                 list_del_init(&entry->list);
1103         }
1104
1105         return 0;
1106 }
1107
1108 static int flush_dirty_cache(struct inode *inode)
1109 {
1110         int ret;
1111
1112         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1113         if (ret)
1114                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1115                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1116                                  GFP_NOFS);
1117
1118         return ret;
1119 }
1120
1121 static void noinline_for_stack
1122 cleanup_write_cache_enospc(struct inode *inode,
1123                            struct btrfs_io_ctl *io_ctl,
1124                            struct extent_state **cached_state,
1125                            struct list_head *bitmap_list)
1126 {
1127         struct list_head *pos, *n;
1128
1129         list_for_each_safe(pos, n, bitmap_list) {
1130                 struct btrfs_free_space *entry =
1131                         list_entry(pos, struct btrfs_free_space, list);
1132                 list_del_init(&entry->list);
1133         }
1134         io_ctl_drop_pages(io_ctl);
1135         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1136                              i_size_read(inode) - 1, cached_state,
1137                              GFP_NOFS);
1138 }
1139
1140 int btrfs_wait_cache_io(struct btrfs_root *root,
1141                         struct btrfs_trans_handle *trans,
1142                         struct btrfs_block_group_cache *block_group,
1143                         struct btrfs_io_ctl *io_ctl,
1144                         struct btrfs_path *path, u64 offset)
1145 {
1146         int ret;
1147         struct inode *inode = io_ctl->inode;
1148
1149         if (!inode)
1150                 return 0;
1151
1152         root = root->fs_info->tree_root;
1153
1154         /* Flush the dirty pages in the cache file. */
1155         ret = flush_dirty_cache(inode);
1156         if (ret)
1157                 goto out;
1158
1159         /* Update the cache item to tell everyone this cache file is valid. */
1160         ret = update_cache_item(trans, root, inode, path, offset,
1161                                 io_ctl->entries, io_ctl->bitmaps);
1162 out:
1163         io_ctl_free(io_ctl);
1164         if (ret) {
1165                 invalidate_inode_pages2(inode->i_mapping);
1166                 BTRFS_I(inode)->generation = 0;
1167                 if (block_group) {
1168 #ifdef DEBUG
1169                         btrfs_err(root->fs_info,
1170                                 "failed to write free space cache for block group %llu",
1171                                 block_group->key.objectid);
1172 #endif
1173                 }
1174         }
1175         btrfs_update_inode(trans, root, inode);
1176
1177         if (block_group) {
1178                 /* the dirty list is protected by the dirty_bgs_lock */
1179                 spin_lock(&trans->transaction->dirty_bgs_lock);
1180
1181                 /* the disk_cache_state is protected by the block group lock */
1182                 spin_lock(&block_group->lock);
1183
1184                 /*
1185                  * only mark this as written if we didn't get put back on
1186                  * the dirty list while waiting for IO.   Otherwise our
1187                  * cache state won't be right, and we won't get written again
1188                  */
1189                 if (!ret && list_empty(&block_group->dirty_list))
1190                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1191                 else if (ret)
1192                         block_group->disk_cache_state = BTRFS_DC_ERROR;
1193
1194                 spin_unlock(&block_group->lock);
1195                 spin_unlock(&trans->transaction->dirty_bgs_lock);
1196                 io_ctl->inode = NULL;
1197                 iput(inode);
1198         }
1199
1200         return ret;
1201
1202 }
1203
1204 /**
1205  * __btrfs_write_out_cache - write out cached info to an inode
1206  * @root - the root the inode belongs to
1207  * @ctl - the free space cache we are going to write out
1208  * @block_group - the block_group for this cache if it belongs to a block_group
1209  * @trans - the trans handle
1210  * @path - the path to use
1211  * @offset - the offset for the key we'll insert
1212  *
1213  * This function writes out a free space cache struct to disk for quick recovery
1214  * on mount.  This will return 0 if it was successfull in writing the cache out,
1215  * and -1 if it was not.
1216  */
1217 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1218                                    struct btrfs_free_space_ctl *ctl,
1219                                    struct btrfs_block_group_cache *block_group,
1220                                    struct btrfs_io_ctl *io_ctl,
1221                                    struct btrfs_trans_handle *trans,
1222                                    struct btrfs_path *path, u64 offset)
1223 {
1224         struct extent_state *cached_state = NULL;
1225         LIST_HEAD(bitmap_list);
1226         int entries = 0;
1227         int bitmaps = 0;
1228         int ret;
1229         int must_iput = 0;
1230
1231         if (!i_size_read(inode))
1232                 return -1;
1233
1234         WARN_ON(io_ctl->pages);
1235         ret = io_ctl_init(io_ctl, inode, root, 1);
1236         if (ret)
1237                 return -1;
1238
1239         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1240                 down_write(&block_group->data_rwsem);
1241                 spin_lock(&block_group->lock);
1242                 if (block_group->delalloc_bytes) {
1243                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1244                         spin_unlock(&block_group->lock);
1245                         up_write(&block_group->data_rwsem);
1246                         BTRFS_I(inode)->generation = 0;
1247                         ret = 0;
1248                         must_iput = 1;
1249                         goto out;
1250                 }
1251                 spin_unlock(&block_group->lock);
1252         }
1253
1254         /* Lock all pages first so we can lock the extent safely. */
1255         io_ctl_prepare_pages(io_ctl, inode, 0);
1256
1257         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1258                          0, &cached_state);
1259
1260         io_ctl_set_generation(io_ctl, trans->transid);
1261
1262         mutex_lock(&ctl->cache_writeout_mutex);
1263         /* Write out the extent entries in the free space cache */
1264         spin_lock(&ctl->tree_lock);
1265         ret = write_cache_extent_entries(io_ctl, ctl,
1266                                          block_group, &entries, &bitmaps,
1267                                          &bitmap_list);
1268         spin_unlock(&ctl->tree_lock);
1269         if (ret) {
1270                 mutex_unlock(&ctl->cache_writeout_mutex);
1271                 goto out_nospc;
1272         }
1273
1274         /*
1275          * Some spaces that are freed in the current transaction are pinned,
1276          * they will be added into free space cache after the transaction is
1277          * committed, we shouldn't lose them.
1278          *
1279          * If this changes while we are working we'll get added back to
1280          * the dirty list and redo it.  No locking needed
1281          */
1282         ret = write_pinned_extent_entries(root, block_group, io_ctl, &entries);
1283         if (ret) {
1284                 mutex_unlock(&ctl->cache_writeout_mutex);
1285                 goto out_nospc;
1286         }
1287
1288         /*
1289          * At last, we write out all the bitmaps and keep cache_writeout_mutex
1290          * locked while doing it because a concurrent trim can be manipulating
1291          * or freeing the bitmap.
1292          */
1293         spin_lock(&ctl->tree_lock);
1294         ret = write_bitmap_entries(io_ctl, &bitmap_list);
1295         spin_unlock(&ctl->tree_lock);
1296         mutex_unlock(&ctl->cache_writeout_mutex);
1297         if (ret)
1298                 goto out_nospc;
1299
1300         /* Zero out the rest of the pages just to make sure */
1301         io_ctl_zero_remaining_pages(io_ctl);
1302
1303         /* Everything is written out, now we dirty the pages in the file. */
1304         ret = btrfs_dirty_pages(root, inode, io_ctl->pages, io_ctl->num_pages,
1305                                 0, i_size_read(inode), &cached_state);
1306         if (ret)
1307                 goto out_nospc;
1308
1309         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1310                 up_write(&block_group->data_rwsem);
1311         /*
1312          * Release the pages and unlock the extent, we will flush
1313          * them out later
1314          */
1315         io_ctl_drop_pages(io_ctl);
1316
1317         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1318                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1319
1320         /*
1321          * at this point the pages are under IO and we're happy,
1322          * The caller is responsible for waiting on them and updating the
1323          * the cache and the inode
1324          */
1325         io_ctl->entries = entries;
1326         io_ctl->bitmaps = bitmaps;
1327
1328         ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
1329         if (ret)
1330                 goto out;
1331
1332         return 0;
1333
1334 out:
1335         io_ctl->inode = NULL;
1336         io_ctl_free(io_ctl);
1337         if (ret) {
1338                 invalidate_inode_pages2(inode->i_mapping);
1339                 BTRFS_I(inode)->generation = 0;
1340         }
1341         btrfs_update_inode(trans, root, inode);
1342         if (must_iput)
1343                 iput(inode);
1344         return ret;
1345
1346 out_nospc:
1347         cleanup_write_cache_enospc(inode, io_ctl, &cached_state, &bitmap_list);
1348
1349         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1350                 up_write(&block_group->data_rwsem);
1351
1352         goto out;
1353 }
1354
1355 int btrfs_write_out_cache(struct btrfs_root *root,
1356                           struct btrfs_trans_handle *trans,
1357                           struct btrfs_block_group_cache *block_group,
1358                           struct btrfs_path *path)
1359 {
1360         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1361         struct inode *inode;
1362         int ret = 0;
1363
1364         root = root->fs_info->tree_root;
1365
1366         spin_lock(&block_group->lock);
1367         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1368                 spin_unlock(&block_group->lock);
1369                 return 0;
1370         }
1371         spin_unlock(&block_group->lock);
1372
1373         inode = lookup_free_space_inode(root, block_group, path);
1374         if (IS_ERR(inode))
1375                 return 0;
1376
1377         ret = __btrfs_write_out_cache(root, inode, ctl, block_group,
1378                                       &block_group->io_ctl, trans,
1379                                       path, block_group->key.objectid);
1380         if (ret) {
1381 #ifdef DEBUG
1382                 btrfs_err(root->fs_info,
1383                         "failed to write free space cache for block group %llu",
1384                         block_group->key.objectid);
1385 #endif
1386                 spin_lock(&block_group->lock);
1387                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1388                 spin_unlock(&block_group->lock);
1389
1390                 block_group->io_ctl.inode = NULL;
1391                 iput(inode);
1392         }
1393
1394         /*
1395          * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1396          * to wait for IO and put the inode
1397          */
1398
1399         return ret;
1400 }
1401
1402 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1403                                           u64 offset)
1404 {
1405         ASSERT(offset >= bitmap_start);
1406         offset -= bitmap_start;
1407         return (unsigned long)(div_u64(offset, unit));
1408 }
1409
1410 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1411 {
1412         return (unsigned long)(div_u64(bytes, unit));
1413 }
1414
1415 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1416                                    u64 offset)
1417 {
1418         u64 bitmap_start;
1419         u32 bytes_per_bitmap;
1420
1421         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1422         bitmap_start = offset - ctl->start;
1423         bitmap_start = div_u64(bitmap_start, bytes_per_bitmap);
1424         bitmap_start *= bytes_per_bitmap;
1425         bitmap_start += ctl->start;
1426
1427         return bitmap_start;
1428 }
1429
1430 static int tree_insert_offset(struct rb_root *root, u64 offset,
1431                               struct rb_node *node, int bitmap)
1432 {
1433         struct rb_node **p = &root->rb_node;
1434         struct rb_node *parent = NULL;
1435         struct btrfs_free_space *info;
1436
1437         while (*p) {
1438                 parent = *p;
1439                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1440
1441                 if (offset < info->offset) {
1442                         p = &(*p)->rb_left;
1443                 } else if (offset > info->offset) {
1444                         p = &(*p)->rb_right;
1445                 } else {
1446                         /*
1447                          * we could have a bitmap entry and an extent entry
1448                          * share the same offset.  If this is the case, we want
1449                          * the extent entry to always be found first if we do a
1450                          * linear search through the tree, since we want to have
1451                          * the quickest allocation time, and allocating from an
1452                          * extent is faster than allocating from a bitmap.  So
1453                          * if we're inserting a bitmap and we find an entry at
1454                          * this offset, we want to go right, or after this entry
1455                          * logically.  If we are inserting an extent and we've
1456                          * found a bitmap, we want to go left, or before
1457                          * logically.
1458                          */
1459                         if (bitmap) {
1460                                 if (info->bitmap) {
1461                                         WARN_ON_ONCE(1);
1462                                         return -EEXIST;
1463                                 }
1464                                 p = &(*p)->rb_right;
1465                         } else {
1466                                 if (!info->bitmap) {
1467                                         WARN_ON_ONCE(1);
1468                                         return -EEXIST;
1469                                 }
1470                                 p = &(*p)->rb_left;
1471                         }
1472                 }
1473         }
1474
1475         rb_link_node(node, parent, p);
1476         rb_insert_color(node, root);
1477
1478         return 0;
1479 }
1480
1481 /*
1482  * searches the tree for the given offset.
1483  *
1484  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1485  * want a section that has at least bytes size and comes at or after the given
1486  * offset.
1487  */
1488 static struct btrfs_free_space *
1489 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1490                    u64 offset, int bitmap_only, int fuzzy)
1491 {
1492         struct rb_node *n = ctl->free_space_offset.rb_node;
1493         struct btrfs_free_space *entry, *prev = NULL;
1494
1495         /* find entry that is closest to the 'offset' */
1496         while (1) {
1497                 if (!n) {
1498                         entry = NULL;
1499                         break;
1500                 }
1501
1502                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1503                 prev = entry;
1504
1505                 if (offset < entry->offset)
1506                         n = n->rb_left;
1507                 else if (offset > entry->offset)
1508                         n = n->rb_right;
1509                 else
1510                         break;
1511         }
1512
1513         if (bitmap_only) {
1514                 if (!entry)
1515                         return NULL;
1516                 if (entry->bitmap)
1517                         return entry;
1518
1519                 /*
1520                  * bitmap entry and extent entry may share same offset,
1521                  * in that case, bitmap entry comes after extent entry.
1522                  */
1523                 n = rb_next(n);
1524                 if (!n)
1525                         return NULL;
1526                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1527                 if (entry->offset != offset)
1528                         return NULL;
1529
1530                 WARN_ON(!entry->bitmap);
1531                 return entry;
1532         } else if (entry) {
1533                 if (entry->bitmap) {
1534                         /*
1535                          * if previous extent entry covers the offset,
1536                          * we should return it instead of the bitmap entry
1537                          */
1538                         n = rb_prev(&entry->offset_index);
1539                         if (n) {
1540                                 prev = rb_entry(n, struct btrfs_free_space,
1541                                                 offset_index);
1542                                 if (!prev->bitmap &&
1543                                     prev->offset + prev->bytes > offset)
1544                                         entry = prev;
1545                         }
1546                 }
1547                 return entry;
1548         }
1549
1550         if (!prev)
1551                 return NULL;
1552
1553         /* find last entry before the 'offset' */
1554         entry = prev;
1555         if (entry->offset > offset) {
1556                 n = rb_prev(&entry->offset_index);
1557                 if (n) {
1558                         entry = rb_entry(n, struct btrfs_free_space,
1559                                         offset_index);
1560                         ASSERT(entry->offset <= offset);
1561                 } else {
1562                         if (fuzzy)
1563                                 return entry;
1564                         else
1565                                 return NULL;
1566                 }
1567         }
1568
1569         if (entry->bitmap) {
1570                 n = rb_prev(&entry->offset_index);
1571                 if (n) {
1572                         prev = rb_entry(n, struct btrfs_free_space,
1573                                         offset_index);
1574                         if (!prev->bitmap &&
1575                             prev->offset + prev->bytes > offset)
1576                                 return prev;
1577                 }
1578                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1579                         return entry;
1580         } else if (entry->offset + entry->bytes > offset)
1581                 return entry;
1582
1583         if (!fuzzy)
1584                 return NULL;
1585
1586         while (1) {
1587                 if (entry->bitmap) {
1588                         if (entry->offset + BITS_PER_BITMAP *
1589                             ctl->unit > offset)
1590                                 break;
1591                 } else {
1592                         if (entry->offset + entry->bytes > offset)
1593                                 break;
1594                 }
1595
1596                 n = rb_next(&entry->offset_index);
1597                 if (!n)
1598                         return NULL;
1599                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1600         }
1601         return entry;
1602 }
1603
1604 static inline void
1605 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1606                     struct btrfs_free_space *info)
1607 {
1608         rb_erase(&info->offset_index, &ctl->free_space_offset);
1609         ctl->free_extents--;
1610 }
1611
1612 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1613                               struct btrfs_free_space *info)
1614 {
1615         __unlink_free_space(ctl, info);
1616         ctl->free_space -= info->bytes;
1617 }
1618
1619 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1620                            struct btrfs_free_space *info)
1621 {
1622         int ret = 0;
1623
1624         ASSERT(info->bytes || info->bitmap);
1625         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1626                                  &info->offset_index, (info->bitmap != NULL));
1627         if (ret)
1628                 return ret;
1629
1630         ctl->free_space += info->bytes;
1631         ctl->free_extents++;
1632         return ret;
1633 }
1634
1635 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1636 {
1637         struct btrfs_block_group_cache *block_group = ctl->private;
1638         u64 max_bytes;
1639         u64 bitmap_bytes;
1640         u64 extent_bytes;
1641         u64 size = block_group->key.offset;
1642         u32 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1643         u32 max_bitmaps = div_u64(size + bytes_per_bg - 1, bytes_per_bg);
1644
1645         max_bitmaps = max_t(u32, max_bitmaps, 1);
1646
1647         ASSERT(ctl->total_bitmaps <= max_bitmaps);
1648
1649         /*
1650          * The goal is to keep the total amount of memory used per 1gb of space
1651          * at or below 32k, so we need to adjust how much memory we allow to be
1652          * used by extent based free space tracking
1653          */
1654         if (size < 1024 * 1024 * 1024)
1655                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1656         else
1657                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1658                         div_u64(size, 1024 * 1024 * 1024);
1659
1660         /*
1661          * we want to account for 1 more bitmap than what we have so we can make
1662          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1663          * we add more bitmaps.
1664          */
1665         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1666
1667         if (bitmap_bytes >= max_bytes) {
1668                 ctl->extents_thresh = 0;
1669                 return;
1670         }
1671
1672         /*
1673          * we want the extent entry threshold to always be at most 1/2 the max
1674          * bytes we can have, or whatever is less than that.
1675          */
1676         extent_bytes = max_bytes - bitmap_bytes;
1677         extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
1678
1679         ctl->extents_thresh =
1680                 div_u64(extent_bytes, sizeof(struct btrfs_free_space));
1681 }
1682
1683 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1684                                        struct btrfs_free_space *info,
1685                                        u64 offset, u64 bytes)
1686 {
1687         unsigned long start, count;
1688
1689         start = offset_to_bit(info->offset, ctl->unit, offset);
1690         count = bytes_to_bits(bytes, ctl->unit);
1691         ASSERT(start + count <= BITS_PER_BITMAP);
1692
1693         bitmap_clear(info->bitmap, start, count);
1694
1695         info->bytes -= bytes;
1696 }
1697
1698 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1699                               struct btrfs_free_space *info, u64 offset,
1700                               u64 bytes)
1701 {
1702         __bitmap_clear_bits(ctl, info, offset, bytes);
1703         ctl->free_space -= bytes;
1704 }
1705
1706 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1707                             struct btrfs_free_space *info, u64 offset,
1708                             u64 bytes)
1709 {
1710         unsigned long start, count;
1711
1712         start = offset_to_bit(info->offset, ctl->unit, offset);
1713         count = bytes_to_bits(bytes, ctl->unit);
1714         ASSERT(start + count <= BITS_PER_BITMAP);
1715
1716         bitmap_set(info->bitmap, start, count);
1717
1718         info->bytes += bytes;
1719         ctl->free_space += bytes;
1720 }
1721
1722 /*
1723  * If we can not find suitable extent, we will use bytes to record
1724  * the size of the max extent.
1725  */
1726 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1727                          struct btrfs_free_space *bitmap_info, u64 *offset,
1728                          u64 *bytes)
1729 {
1730         unsigned long found_bits = 0;
1731         unsigned long max_bits = 0;
1732         unsigned long bits, i;
1733         unsigned long next_zero;
1734         unsigned long extent_bits;
1735
1736         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1737                           max_t(u64, *offset, bitmap_info->offset));
1738         bits = bytes_to_bits(*bytes, ctl->unit);
1739
1740         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1741                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1742                                                BITS_PER_BITMAP, i);
1743                 extent_bits = next_zero - i;
1744                 if (extent_bits >= bits) {
1745                         found_bits = extent_bits;
1746                         break;
1747                 } else if (extent_bits > max_bits) {
1748                         max_bits = extent_bits;
1749                 }
1750                 i = next_zero;
1751         }
1752
1753         if (found_bits) {
1754                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1755                 *bytes = (u64)(found_bits) * ctl->unit;
1756                 return 0;
1757         }
1758
1759         *bytes = (u64)(max_bits) * ctl->unit;
1760         return -1;
1761 }
1762
1763 /* Cache the size of the max extent in bytes */
1764 static struct btrfs_free_space *
1765 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1766                 unsigned long align, u64 *max_extent_size)
1767 {
1768         struct btrfs_free_space *entry;
1769         struct rb_node *node;
1770         u64 tmp;
1771         u64 align_off;
1772         int ret;
1773
1774         if (!ctl->free_space_offset.rb_node)
1775                 goto out;
1776
1777         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1778         if (!entry)
1779                 goto out;
1780
1781         for (node = &entry->offset_index; node; node = rb_next(node)) {
1782                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1783                 if (entry->bytes < *bytes) {
1784                         if (entry->bytes > *max_extent_size)
1785                                 *max_extent_size = entry->bytes;
1786                         continue;
1787                 }
1788
1789                 /* make sure the space returned is big enough
1790                  * to match our requested alignment
1791                  */
1792                 if (*bytes >= align) {
1793                         tmp = entry->offset - ctl->start + align - 1;
1794                         tmp = div64_u64(tmp, align);
1795                         tmp = tmp * align + ctl->start;
1796                         align_off = tmp - entry->offset;
1797                 } else {
1798                         align_off = 0;
1799                         tmp = entry->offset;
1800                 }
1801
1802                 if (entry->bytes < *bytes + align_off) {
1803                         if (entry->bytes > *max_extent_size)
1804                                 *max_extent_size = entry->bytes;
1805                         continue;
1806                 }
1807
1808                 if (entry->bitmap) {
1809                         u64 size = *bytes;
1810
1811                         ret = search_bitmap(ctl, entry, &tmp, &size);
1812                         if (!ret) {
1813                                 *offset = tmp;
1814                                 *bytes = size;
1815                                 return entry;
1816                         } else if (size > *max_extent_size) {
1817                                 *max_extent_size = size;
1818                         }
1819                         continue;
1820                 }
1821
1822                 *offset = tmp;
1823                 *bytes = entry->bytes - align_off;
1824                 return entry;
1825         }
1826 out:
1827         return NULL;
1828 }
1829
1830 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1831                            struct btrfs_free_space *info, u64 offset)
1832 {
1833         info->offset = offset_to_bitmap(ctl, offset);
1834         info->bytes = 0;
1835         INIT_LIST_HEAD(&info->list);
1836         link_free_space(ctl, info);
1837         ctl->total_bitmaps++;
1838
1839         ctl->op->recalc_thresholds(ctl);
1840 }
1841
1842 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1843                         struct btrfs_free_space *bitmap_info)
1844 {
1845         unlink_free_space(ctl, bitmap_info);
1846         kfree(bitmap_info->bitmap);
1847         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1848         ctl->total_bitmaps--;
1849         ctl->op->recalc_thresholds(ctl);
1850 }
1851
1852 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1853                               struct btrfs_free_space *bitmap_info,
1854                               u64 *offset, u64 *bytes)
1855 {
1856         u64 end;
1857         u64 search_start, search_bytes;
1858         int ret;
1859
1860 again:
1861         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1862
1863         /*
1864          * We need to search for bits in this bitmap.  We could only cover some
1865          * of the extent in this bitmap thanks to how we add space, so we need
1866          * to search for as much as it as we can and clear that amount, and then
1867          * go searching for the next bit.
1868          */
1869         search_start = *offset;
1870         search_bytes = ctl->unit;
1871         search_bytes = min(search_bytes, end - search_start + 1);
1872         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1873         if (ret < 0 || search_start != *offset)
1874                 return -EINVAL;
1875
1876         /* We may have found more bits than what we need */
1877         search_bytes = min(search_bytes, *bytes);
1878
1879         /* Cannot clear past the end of the bitmap */
1880         search_bytes = min(search_bytes, end - search_start + 1);
1881
1882         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1883         *offset += search_bytes;
1884         *bytes -= search_bytes;
1885
1886         if (*bytes) {
1887                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1888                 if (!bitmap_info->bytes)
1889                         free_bitmap(ctl, bitmap_info);
1890
1891                 /*
1892                  * no entry after this bitmap, but we still have bytes to
1893                  * remove, so something has gone wrong.
1894                  */
1895                 if (!next)
1896                         return -EINVAL;
1897
1898                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1899                                        offset_index);
1900
1901                 /*
1902                  * if the next entry isn't a bitmap we need to return to let the
1903                  * extent stuff do its work.
1904                  */
1905                 if (!bitmap_info->bitmap)
1906                         return -EAGAIN;
1907
1908                 /*
1909                  * Ok the next item is a bitmap, but it may not actually hold
1910                  * the information for the rest of this free space stuff, so
1911                  * look for it, and if we don't find it return so we can try
1912                  * everything over again.
1913                  */
1914                 search_start = *offset;
1915                 search_bytes = ctl->unit;
1916                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1917                                     &search_bytes);
1918                 if (ret < 0 || search_start != *offset)
1919                         return -EAGAIN;
1920
1921                 goto again;
1922         } else if (!bitmap_info->bytes)
1923                 free_bitmap(ctl, bitmap_info);
1924
1925         return 0;
1926 }
1927
1928 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1929                                struct btrfs_free_space *info, u64 offset,
1930                                u64 bytes)
1931 {
1932         u64 bytes_to_set = 0;
1933         u64 end;
1934
1935         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1936
1937         bytes_to_set = min(end - offset, bytes);
1938
1939         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1940
1941         return bytes_to_set;
1942
1943 }
1944
1945 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1946                       struct btrfs_free_space *info)
1947 {
1948         struct btrfs_block_group_cache *block_group = ctl->private;
1949
1950         /*
1951          * If we are below the extents threshold then we can add this as an
1952          * extent, and don't have to deal with the bitmap
1953          */
1954         if (ctl->free_extents < ctl->extents_thresh) {
1955                 /*
1956                  * If this block group has some small extents we don't want to
1957                  * use up all of our free slots in the cache with them, we want
1958                  * to reserve them to larger extents, however if we have plent
1959                  * of cache left then go ahead an dadd them, no sense in adding
1960                  * the overhead of a bitmap if we don't have to.
1961                  */
1962                 if (info->bytes <= block_group->sectorsize * 4) {
1963                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1964                                 return false;
1965                 } else {
1966                         return false;
1967                 }
1968         }
1969
1970         /*
1971          * The original block groups from mkfs can be really small, like 8
1972          * megabytes, so don't bother with a bitmap for those entries.  However
1973          * some block groups can be smaller than what a bitmap would cover but
1974          * are still large enough that they could overflow the 32k memory limit,
1975          * so allow those block groups to still be allowed to have a bitmap
1976          * entry.
1977          */
1978         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1979                 return false;
1980
1981         return true;
1982 }
1983
1984 static struct btrfs_free_space_op free_space_op = {
1985         .recalc_thresholds      = recalculate_thresholds,
1986         .use_bitmap             = use_bitmap,
1987 };
1988
1989 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1990                               struct btrfs_free_space *info)
1991 {
1992         struct btrfs_free_space *bitmap_info;
1993         struct btrfs_block_group_cache *block_group = NULL;
1994         int added = 0;
1995         u64 bytes, offset, bytes_added;
1996         int ret;
1997
1998         bytes = info->bytes;
1999         offset = info->offset;
2000
2001         if (!ctl->op->use_bitmap(ctl, info))
2002                 return 0;
2003
2004         if (ctl->op == &free_space_op)
2005                 block_group = ctl->private;
2006 again:
2007         /*
2008          * Since we link bitmaps right into the cluster we need to see if we
2009          * have a cluster here, and if so and it has our bitmap we need to add
2010          * the free space to that bitmap.
2011          */
2012         if (block_group && !list_empty(&block_group->cluster_list)) {
2013                 struct btrfs_free_cluster *cluster;
2014                 struct rb_node *node;
2015                 struct btrfs_free_space *entry;
2016
2017                 cluster = list_entry(block_group->cluster_list.next,
2018                                      struct btrfs_free_cluster,
2019                                      block_group_list);
2020                 spin_lock(&cluster->lock);
2021                 node = rb_first(&cluster->root);
2022                 if (!node) {
2023                         spin_unlock(&cluster->lock);
2024                         goto no_cluster_bitmap;
2025                 }
2026
2027                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2028                 if (!entry->bitmap) {
2029                         spin_unlock(&cluster->lock);
2030                         goto no_cluster_bitmap;
2031                 }
2032
2033                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
2034                         bytes_added = add_bytes_to_bitmap(ctl, entry,
2035                                                           offset, bytes);
2036                         bytes -= bytes_added;
2037                         offset += bytes_added;
2038                 }
2039                 spin_unlock(&cluster->lock);
2040                 if (!bytes) {
2041                         ret = 1;
2042                         goto out;
2043                 }
2044         }
2045
2046 no_cluster_bitmap:
2047         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2048                                          1, 0);
2049         if (!bitmap_info) {
2050                 ASSERT(added == 0);
2051                 goto new_bitmap;
2052         }
2053
2054         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
2055         bytes -= bytes_added;
2056         offset += bytes_added;
2057         added = 0;
2058
2059         if (!bytes) {
2060                 ret = 1;
2061                 goto out;
2062         } else
2063                 goto again;
2064
2065 new_bitmap:
2066         if (info && info->bitmap) {
2067                 add_new_bitmap(ctl, info, offset);
2068                 added = 1;
2069                 info = NULL;
2070                 goto again;
2071         } else {
2072                 spin_unlock(&ctl->tree_lock);
2073
2074                 /* no pre-allocated info, allocate a new one */
2075                 if (!info) {
2076                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
2077                                                  GFP_NOFS);
2078                         if (!info) {
2079                                 spin_lock(&ctl->tree_lock);
2080                                 ret = -ENOMEM;
2081                                 goto out;
2082                         }
2083                 }
2084
2085                 /* allocate the bitmap */
2086                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
2087                 spin_lock(&ctl->tree_lock);
2088                 if (!info->bitmap) {
2089                         ret = -ENOMEM;
2090                         goto out;
2091                 }
2092                 goto again;
2093         }
2094
2095 out:
2096         if (info) {
2097                 if (info->bitmap)
2098                         kfree(info->bitmap);
2099                 kmem_cache_free(btrfs_free_space_cachep, info);
2100         }
2101
2102         return ret;
2103 }
2104
2105 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2106                           struct btrfs_free_space *info, bool update_stat)
2107 {
2108         struct btrfs_free_space *left_info;
2109         struct btrfs_free_space *right_info;
2110         bool merged = false;
2111         u64 offset = info->offset;
2112         u64 bytes = info->bytes;
2113
2114         /*
2115          * first we want to see if there is free space adjacent to the range we
2116          * are adding, if there is remove that struct and add a new one to
2117          * cover the entire range
2118          */
2119         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2120         if (right_info && rb_prev(&right_info->offset_index))
2121                 left_info = rb_entry(rb_prev(&right_info->offset_index),
2122                                      struct btrfs_free_space, offset_index);
2123         else
2124                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2125
2126         if (right_info && !right_info->bitmap) {
2127                 if (update_stat)
2128                         unlink_free_space(ctl, right_info);
2129                 else
2130                         __unlink_free_space(ctl, right_info);
2131                 info->bytes += right_info->bytes;
2132                 kmem_cache_free(btrfs_free_space_cachep, right_info);
2133                 merged = true;
2134         }
2135
2136         if (left_info && !left_info->bitmap &&
2137             left_info->offset + left_info->bytes == offset) {
2138                 if (update_stat)
2139                         unlink_free_space(ctl, left_info);
2140                 else
2141                         __unlink_free_space(ctl, left_info);
2142                 info->offset = left_info->offset;
2143                 info->bytes += left_info->bytes;
2144                 kmem_cache_free(btrfs_free_space_cachep, left_info);
2145                 merged = true;
2146         }
2147
2148         return merged;
2149 }
2150
2151 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2152                                      struct btrfs_free_space *info,
2153                                      bool update_stat)
2154 {
2155         struct btrfs_free_space *bitmap;
2156         unsigned long i;
2157         unsigned long j;
2158         const u64 end = info->offset + info->bytes;
2159         const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2160         u64 bytes;
2161
2162         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2163         if (!bitmap)
2164                 return false;
2165
2166         i = offset_to_bit(bitmap->offset, ctl->unit, end);
2167         j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2168         if (j == i)
2169                 return false;
2170         bytes = (j - i) * ctl->unit;
2171         info->bytes += bytes;
2172
2173         if (update_stat)
2174                 bitmap_clear_bits(ctl, bitmap, end, bytes);
2175         else
2176                 __bitmap_clear_bits(ctl, bitmap, end, bytes);
2177
2178         if (!bitmap->bytes)
2179                 free_bitmap(ctl, bitmap);
2180
2181         return true;
2182 }
2183
2184 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2185                                        struct btrfs_free_space *info,
2186                                        bool update_stat)
2187 {
2188         struct btrfs_free_space *bitmap;
2189         u64 bitmap_offset;
2190         unsigned long i;
2191         unsigned long j;
2192         unsigned long prev_j;
2193         u64 bytes;
2194
2195         bitmap_offset = offset_to_bitmap(ctl, info->offset);
2196         /* If we're on a boundary, try the previous logical bitmap. */
2197         if (bitmap_offset == info->offset) {
2198                 if (info->offset == 0)
2199                         return false;
2200                 bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2201         }
2202
2203         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2204         if (!bitmap)
2205                 return false;
2206
2207         i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2208         j = 0;
2209         prev_j = (unsigned long)-1;
2210         for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2211                 if (j > i)
2212                         break;
2213                 prev_j = j;
2214         }
2215         if (prev_j == i)
2216                 return false;
2217
2218         if (prev_j == (unsigned long)-1)
2219                 bytes = (i + 1) * ctl->unit;
2220         else
2221                 bytes = (i - prev_j) * ctl->unit;
2222
2223         info->offset -= bytes;
2224         info->bytes += bytes;
2225
2226         if (update_stat)
2227                 bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2228         else
2229                 __bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2230
2231         if (!bitmap->bytes)
2232                 free_bitmap(ctl, bitmap);
2233
2234         return true;
2235 }
2236
2237 /*
2238  * We prefer always to allocate from extent entries, both for clustered and
2239  * non-clustered allocation requests. So when attempting to add a new extent
2240  * entry, try to see if there's adjacent free space in bitmap entries, and if
2241  * there is, migrate that space from the bitmaps to the extent.
2242  * Like this we get better chances of satisfying space allocation requests
2243  * because we attempt to satisfy them based on a single cache entry, and never
2244  * on 2 or more entries - even if the entries represent a contiguous free space
2245  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2246  * ends).
2247  */
2248 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2249                               struct btrfs_free_space *info,
2250                               bool update_stat)
2251 {
2252         /*
2253          * Only work with disconnected entries, as we can change their offset,
2254          * and must be extent entries.
2255          */
2256         ASSERT(!info->bitmap);
2257         ASSERT(RB_EMPTY_NODE(&info->offset_index));
2258
2259         if (ctl->total_bitmaps > 0) {
2260                 bool stole_end;
2261                 bool stole_front = false;
2262
2263                 stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2264                 if (ctl->total_bitmaps > 0)
2265                         stole_front = steal_from_bitmap_to_front(ctl, info,
2266                                                                  update_stat);
2267
2268                 if (stole_end || stole_front)
2269                         try_merge_free_space(ctl, info, update_stat);
2270         }
2271 }
2272
2273 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
2274                            u64 offset, u64 bytes)
2275 {
2276         struct btrfs_free_space *info;
2277         int ret = 0;
2278
2279         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2280         if (!info)
2281                 return -ENOMEM;
2282
2283         info->offset = offset;
2284         info->bytes = bytes;
2285         RB_CLEAR_NODE(&info->offset_index);
2286
2287         spin_lock(&ctl->tree_lock);
2288
2289         if (try_merge_free_space(ctl, info, true))
2290                 goto link;
2291
2292         /*
2293          * There was no extent directly to the left or right of this new
2294          * extent then we know we're going to have to allocate a new extent, so
2295          * before we do that see if we need to drop this into a bitmap
2296          */
2297         ret = insert_into_bitmap(ctl, info);
2298         if (ret < 0) {
2299                 goto out;
2300         } else if (ret) {
2301                 ret = 0;
2302                 goto out;
2303         }
2304 link:
2305         /*
2306          * Only steal free space from adjacent bitmaps if we're sure we're not
2307          * going to add the new free space to existing bitmap entries - because
2308          * that would mean unnecessary work that would be reverted. Therefore
2309          * attempt to steal space from bitmaps if we're adding an extent entry.
2310          */
2311         steal_from_bitmap(ctl, info, true);
2312
2313         ret = link_free_space(ctl, info);
2314         if (ret)
2315                 kmem_cache_free(btrfs_free_space_cachep, info);
2316 out:
2317         spin_unlock(&ctl->tree_lock);
2318
2319         if (ret) {
2320                 printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2321                 ASSERT(ret != -EEXIST);
2322         }
2323
2324         return ret;
2325 }
2326
2327 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2328                             u64 offset, u64 bytes)
2329 {
2330         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2331         struct btrfs_free_space *info;
2332         int ret;
2333         bool re_search = false;
2334
2335         spin_lock(&ctl->tree_lock);
2336
2337 again:
2338         ret = 0;
2339         if (!bytes)
2340                 goto out_lock;
2341
2342         info = tree_search_offset(ctl, offset, 0, 0);
2343         if (!info) {
2344                 /*
2345                  * oops didn't find an extent that matched the space we wanted
2346                  * to remove, look for a bitmap instead
2347                  */
2348                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2349                                           1, 0);
2350                 if (!info) {
2351                         /*
2352                          * If we found a partial bit of our free space in a
2353                          * bitmap but then couldn't find the other part this may
2354                          * be a problem, so WARN about it.
2355                          */
2356                         WARN_ON(re_search);
2357                         goto out_lock;
2358                 }
2359         }
2360
2361         re_search = false;
2362         if (!info->bitmap) {
2363                 unlink_free_space(ctl, info);
2364                 if (offset == info->offset) {
2365                         u64 to_free = min(bytes, info->bytes);
2366
2367                         info->bytes -= to_free;
2368                         info->offset += to_free;
2369                         if (info->bytes) {
2370                                 ret = link_free_space(ctl, info);
2371                                 WARN_ON(ret);
2372                         } else {
2373                                 kmem_cache_free(btrfs_free_space_cachep, info);
2374                         }
2375
2376                         offset += to_free;
2377                         bytes -= to_free;
2378                         goto again;
2379                 } else {
2380                         u64 old_end = info->bytes + info->offset;
2381
2382                         info->bytes = offset - info->offset;
2383                         ret = link_free_space(ctl, info);
2384                         WARN_ON(ret);
2385                         if (ret)
2386                                 goto out_lock;
2387
2388                         /* Not enough bytes in this entry to satisfy us */
2389                         if (old_end < offset + bytes) {
2390                                 bytes -= old_end - offset;
2391                                 offset = old_end;
2392                                 goto again;
2393                         } else if (old_end == offset + bytes) {
2394                                 /* all done */
2395                                 goto out_lock;
2396                         }
2397                         spin_unlock(&ctl->tree_lock);
2398
2399                         ret = btrfs_add_free_space(block_group, offset + bytes,
2400                                                    old_end - (offset + bytes));
2401                         WARN_ON(ret);
2402                         goto out;
2403                 }
2404         }
2405
2406         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2407         if (ret == -EAGAIN) {
2408                 re_search = true;
2409                 goto again;
2410         }
2411 out_lock:
2412         spin_unlock(&ctl->tree_lock);
2413 out:
2414         return ret;
2415 }
2416
2417 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2418                            u64 bytes)
2419 {
2420         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2421         struct btrfs_free_space *info;
2422         struct rb_node *n;
2423         int count = 0;
2424
2425         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2426                 info = rb_entry(n, struct btrfs_free_space, offset_index);
2427                 if (info->bytes >= bytes && !block_group->ro)
2428                         count++;
2429                 btrfs_crit(block_group->fs_info,
2430                            "entry offset %llu, bytes %llu, bitmap %s",
2431                            info->offset, info->bytes,
2432                        (info->bitmap) ? "yes" : "no");
2433         }
2434         btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2435                list_empty(&block_group->cluster_list) ? "no" : "yes");
2436         btrfs_info(block_group->fs_info,
2437                    "%d blocks of free space at or bigger than bytes is", count);
2438 }
2439
2440 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2441 {
2442         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2443
2444         spin_lock_init(&ctl->tree_lock);
2445         ctl->unit = block_group->sectorsize;
2446         ctl->start = block_group->key.objectid;
2447         ctl->private = block_group;
2448         ctl->op = &free_space_op;
2449         INIT_LIST_HEAD(&ctl->trimming_ranges);
2450         mutex_init(&ctl->cache_writeout_mutex);
2451
2452         /*
2453          * we only want to have 32k of ram per block group for keeping
2454          * track of free space, and if we pass 1/2 of that we want to
2455          * start converting things over to using bitmaps
2456          */
2457         ctl->extents_thresh = ((1024 * 32) / 2) /
2458                                 sizeof(struct btrfs_free_space);
2459 }
2460
2461 /*
2462  * for a given cluster, put all of its extents back into the free
2463  * space cache.  If the block group passed doesn't match the block group
2464  * pointed to by the cluster, someone else raced in and freed the
2465  * cluster already.  In that case, we just return without changing anything
2466  */
2467 static int
2468 __btrfs_return_cluster_to_free_space(
2469                              struct btrfs_block_group_cache *block_group,
2470                              struct btrfs_free_cluster *cluster)
2471 {
2472         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2473         struct btrfs_free_space *entry;
2474         struct rb_node *node;
2475
2476         spin_lock(&cluster->lock);
2477         if (cluster->block_group != block_group)
2478                 goto out;
2479
2480         cluster->block_group = NULL;
2481         cluster->window_start = 0;
2482         list_del_init(&cluster->block_group_list);
2483
2484         node = rb_first(&cluster->root);
2485         while (node) {
2486                 bool bitmap;
2487
2488                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2489                 node = rb_next(&entry->offset_index);
2490                 rb_erase(&entry->offset_index, &cluster->root);
2491                 RB_CLEAR_NODE(&entry->offset_index);
2492
2493                 bitmap = (entry->bitmap != NULL);
2494                 if (!bitmap) {
2495                         try_merge_free_space(ctl, entry, false);
2496                         steal_from_bitmap(ctl, entry, false);
2497                 }
2498                 tree_insert_offset(&ctl->free_space_offset,
2499                                    entry->offset, &entry->offset_index, bitmap);
2500         }
2501         cluster->root = RB_ROOT;
2502
2503 out:
2504         spin_unlock(&cluster->lock);
2505         btrfs_put_block_group(block_group);
2506         return 0;
2507 }
2508
2509 static void __btrfs_remove_free_space_cache_locked(
2510                                 struct btrfs_free_space_ctl *ctl)
2511 {
2512         struct btrfs_free_space *info;
2513         struct rb_node *node;
2514
2515         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2516                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2517                 if (!info->bitmap) {
2518                         unlink_free_space(ctl, info);
2519                         kmem_cache_free(btrfs_free_space_cachep, info);
2520                 } else {
2521                         free_bitmap(ctl, info);
2522                 }
2523
2524                 cond_resched_lock(&ctl->tree_lock);
2525         }
2526 }
2527
2528 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2529 {
2530         spin_lock(&ctl->tree_lock);
2531         __btrfs_remove_free_space_cache_locked(ctl);
2532         spin_unlock(&ctl->tree_lock);
2533 }
2534
2535 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2536 {
2537         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2538         struct btrfs_free_cluster *cluster;
2539         struct list_head *head;
2540
2541         spin_lock(&ctl->tree_lock);
2542         while ((head = block_group->cluster_list.next) !=
2543                &block_group->cluster_list) {
2544                 cluster = list_entry(head, struct btrfs_free_cluster,
2545                                      block_group_list);
2546
2547                 WARN_ON(cluster->block_group != block_group);
2548                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2549
2550                 cond_resched_lock(&ctl->tree_lock);
2551         }
2552         __btrfs_remove_free_space_cache_locked(ctl);
2553         spin_unlock(&ctl->tree_lock);
2554
2555 }
2556
2557 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2558                                u64 offset, u64 bytes, u64 empty_size,
2559                                u64 *max_extent_size)
2560 {
2561         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2562         struct btrfs_free_space *entry = NULL;
2563         u64 bytes_search = bytes + empty_size;
2564         u64 ret = 0;
2565         u64 align_gap = 0;
2566         u64 align_gap_len = 0;
2567
2568         spin_lock(&ctl->tree_lock);
2569         entry = find_free_space(ctl, &offset, &bytes_search,
2570                                 block_group->full_stripe_len, max_extent_size);
2571         if (!entry)
2572                 goto out;
2573
2574         ret = offset;
2575         if (entry->bitmap) {
2576                 bitmap_clear_bits(ctl, entry, offset, bytes);
2577                 if (!entry->bytes)
2578                         free_bitmap(ctl, entry);
2579         } else {
2580                 unlink_free_space(ctl, entry);
2581                 align_gap_len = offset - entry->offset;
2582                 align_gap = entry->offset;
2583
2584                 entry->offset = offset + bytes;
2585                 WARN_ON(entry->bytes < bytes + align_gap_len);
2586
2587                 entry->bytes -= bytes + align_gap_len;
2588                 if (!entry->bytes)
2589                         kmem_cache_free(btrfs_free_space_cachep, entry);
2590                 else
2591                         link_free_space(ctl, entry);
2592         }
2593 out:
2594         spin_unlock(&ctl->tree_lock);
2595
2596         if (align_gap_len)
2597                 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2598         return ret;
2599 }
2600
2601 /*
2602  * given a cluster, put all of its extents back into the free space
2603  * cache.  If a block group is passed, this function will only free
2604  * a cluster that belongs to the passed block group.
2605  *
2606  * Otherwise, it'll get a reference on the block group pointed to by the
2607  * cluster and remove the cluster from it.
2608  */
2609 int btrfs_return_cluster_to_free_space(
2610                                struct btrfs_block_group_cache *block_group,
2611                                struct btrfs_free_cluster *cluster)
2612 {
2613         struct btrfs_free_space_ctl *ctl;
2614         int ret;
2615
2616         /* first, get a safe pointer to the block group */
2617         spin_lock(&cluster->lock);
2618         if (!block_group) {
2619                 block_group = cluster->block_group;
2620                 if (!block_group) {
2621                         spin_unlock(&cluster->lock);
2622                         return 0;
2623                 }
2624         } else if (cluster->block_group != block_group) {
2625                 /* someone else has already freed it don't redo their work */
2626                 spin_unlock(&cluster->lock);
2627                 return 0;
2628         }
2629         atomic_inc(&block_group->count);
2630         spin_unlock(&cluster->lock);
2631
2632         ctl = block_group->free_space_ctl;
2633
2634         /* now return any extents the cluster had on it */
2635         spin_lock(&ctl->tree_lock);
2636         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2637         spin_unlock(&ctl->tree_lock);
2638
2639         /* finally drop our ref */
2640         btrfs_put_block_group(block_group);
2641         return ret;
2642 }
2643
2644 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2645                                    struct btrfs_free_cluster *cluster,
2646                                    struct btrfs_free_space *entry,
2647                                    u64 bytes, u64 min_start,
2648                                    u64 *max_extent_size)
2649 {
2650         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2651         int err;
2652         u64 search_start = cluster->window_start;
2653         u64 search_bytes = bytes;
2654         u64 ret = 0;
2655
2656         search_start = min_start;
2657         search_bytes = bytes;
2658
2659         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2660         if (err) {
2661                 if (search_bytes > *max_extent_size)
2662                         *max_extent_size = search_bytes;
2663                 return 0;
2664         }
2665
2666         ret = search_start;
2667         __bitmap_clear_bits(ctl, entry, ret, bytes);
2668
2669         return ret;
2670 }
2671
2672 /*
2673  * given a cluster, try to allocate 'bytes' from it, returns 0
2674  * if it couldn't find anything suitably large, or a logical disk offset
2675  * if things worked out
2676  */
2677 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2678                              struct btrfs_free_cluster *cluster, u64 bytes,
2679                              u64 min_start, u64 *max_extent_size)
2680 {
2681         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2682         struct btrfs_free_space *entry = NULL;
2683         struct rb_node *node;
2684         u64 ret = 0;
2685
2686         spin_lock(&cluster->lock);
2687         if (bytes > cluster->max_size)
2688                 goto out;
2689
2690         if (cluster->block_group != block_group)
2691                 goto out;
2692
2693         node = rb_first(&cluster->root);
2694         if (!node)
2695                 goto out;
2696
2697         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2698         while (1) {
2699                 if (entry->bytes < bytes && entry->bytes > *max_extent_size)
2700                         *max_extent_size = entry->bytes;
2701
2702                 if (entry->bytes < bytes ||
2703                     (!entry->bitmap && entry->offset < min_start)) {
2704                         node = rb_next(&entry->offset_index);
2705                         if (!node)
2706                                 break;
2707                         entry = rb_entry(node, struct btrfs_free_space,
2708                                          offset_index);
2709                         continue;
2710                 }
2711
2712                 if (entry->bitmap) {
2713                         ret = btrfs_alloc_from_bitmap(block_group,
2714                                                       cluster, entry, bytes,
2715                                                       cluster->window_start,
2716                                                       max_extent_size);
2717                         if (ret == 0) {
2718                                 node = rb_next(&entry->offset_index);
2719                                 if (!node)
2720                                         break;
2721                                 entry = rb_entry(node, struct btrfs_free_space,
2722                                                  offset_index);
2723                                 continue;
2724                         }
2725                         cluster->window_start += bytes;
2726                 } else {
2727                         ret = entry->offset;
2728
2729                         entry->offset += bytes;
2730                         entry->bytes -= bytes;
2731                 }
2732
2733                 if (entry->bytes == 0)
2734                         rb_erase(&entry->offset_index, &cluster->root);
2735                 break;
2736         }
2737 out:
2738         spin_unlock(&cluster->lock);
2739
2740         if (!ret)
2741                 return 0;
2742
2743         spin_lock(&ctl->tree_lock);
2744
2745         ctl->free_space -= bytes;
2746         if (entry->bytes == 0) {
2747                 ctl->free_extents--;
2748                 if (entry->bitmap) {
2749                         kfree(entry->bitmap);
2750                         ctl->total_bitmaps--;
2751                         ctl->op->recalc_thresholds(ctl);
2752                 }
2753                 kmem_cache_free(btrfs_free_space_cachep, entry);
2754         }
2755
2756         spin_unlock(&ctl->tree_lock);
2757
2758         return ret;
2759 }
2760
2761 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2762                                 struct btrfs_free_space *entry,
2763                                 struct btrfs_free_cluster *cluster,
2764                                 u64 offset, u64 bytes,
2765                                 u64 cont1_bytes, u64 min_bytes)
2766 {
2767         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2768         unsigned long next_zero;
2769         unsigned long i;
2770         unsigned long want_bits;
2771         unsigned long min_bits;
2772         unsigned long found_bits;
2773         unsigned long start = 0;
2774         unsigned long total_found = 0;
2775         int ret;
2776
2777         i = offset_to_bit(entry->offset, ctl->unit,
2778                           max_t(u64, offset, entry->offset));
2779         want_bits = bytes_to_bits(bytes, ctl->unit);
2780         min_bits = bytes_to_bits(min_bytes, ctl->unit);
2781
2782 again:
2783         found_bits = 0;
2784         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2785                 next_zero = find_next_zero_bit(entry->bitmap,
2786                                                BITS_PER_BITMAP, i);
2787                 if (next_zero - i >= min_bits) {
2788                         found_bits = next_zero - i;
2789                         break;
2790                 }
2791                 i = next_zero;
2792         }
2793
2794         if (!found_bits)
2795                 return -ENOSPC;
2796
2797         if (!total_found) {
2798                 start = i;
2799                 cluster->max_size = 0;
2800         }
2801
2802         total_found += found_bits;
2803
2804         if (cluster->max_size < found_bits * ctl->unit)
2805                 cluster->max_size = found_bits * ctl->unit;
2806
2807         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2808                 i = next_zero + 1;
2809                 goto again;
2810         }
2811
2812         cluster->window_start = start * ctl->unit + entry->offset;
2813         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2814         ret = tree_insert_offset(&cluster->root, entry->offset,
2815                                  &entry->offset_index, 1);
2816         ASSERT(!ret); /* -EEXIST; Logic error */
2817
2818         trace_btrfs_setup_cluster(block_group, cluster,
2819                                   total_found * ctl->unit, 1);
2820         return 0;
2821 }
2822
2823 /*
2824  * This searches the block group for just extents to fill the cluster with.
2825  * Try to find a cluster with at least bytes total bytes, at least one
2826  * extent of cont1_bytes, and other clusters of at least min_bytes.
2827  */
2828 static noinline int
2829 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2830                         struct btrfs_free_cluster *cluster,
2831                         struct list_head *bitmaps, u64 offset, u64 bytes,
2832                         u64 cont1_bytes, u64 min_bytes)
2833 {
2834         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2835         struct btrfs_free_space *first = NULL;
2836         struct btrfs_free_space *entry = NULL;
2837         struct btrfs_free_space *last;
2838         struct rb_node *node;
2839         u64 window_free;
2840         u64 max_extent;
2841         u64 total_size = 0;
2842
2843         entry = tree_search_offset(ctl, offset, 0, 1);
2844         if (!entry)
2845                 return -ENOSPC;
2846
2847         /*
2848          * We don't want bitmaps, so just move along until we find a normal
2849          * extent entry.
2850          */
2851         while (entry->bitmap || entry->bytes < min_bytes) {
2852                 if (entry->bitmap && list_empty(&entry->list))
2853                         list_add_tail(&entry->list, bitmaps);
2854                 node = rb_next(&entry->offset_index);
2855                 if (!node)
2856                         return -ENOSPC;
2857                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2858         }
2859
2860         window_free = entry->bytes;
2861         max_extent = entry->bytes;
2862         first = entry;
2863         last = entry;
2864
2865         for (node = rb_next(&entry->offset_index); node;
2866              node = rb_next(&entry->offset_index)) {
2867                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2868
2869                 if (entry->bitmap) {
2870                         if (list_empty(&entry->list))
2871                                 list_add_tail(&entry->list, bitmaps);
2872                         continue;
2873                 }
2874
2875                 if (entry->bytes < min_bytes)
2876                         continue;
2877
2878                 last = entry;
2879                 window_free += entry->bytes;
2880                 if (entry->bytes > max_extent)
2881                         max_extent = entry->bytes;
2882         }
2883
2884         if (window_free < bytes || max_extent < cont1_bytes)
2885                 return -ENOSPC;
2886
2887         cluster->window_start = first->offset;
2888
2889         node = &first->offset_index;
2890
2891         /*
2892          * now we've found our entries, pull them out of the free space
2893          * cache and put them into the cluster rbtree
2894          */
2895         do {
2896                 int ret;
2897
2898                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2899                 node = rb_next(&entry->offset_index);
2900                 if (entry->bitmap || entry->bytes < min_bytes)
2901                         continue;
2902
2903                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2904                 ret = tree_insert_offset(&cluster->root, entry->offset,
2905                                          &entry->offset_index, 0);
2906                 total_size += entry->bytes;
2907                 ASSERT(!ret); /* -EEXIST; Logic error */
2908         } while (node && entry != last);
2909
2910         cluster->max_size = max_extent;
2911         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2912         return 0;
2913 }
2914
2915 /*
2916  * This specifically looks for bitmaps that may work in the cluster, we assume
2917  * that we have already failed to find extents that will work.
2918  */
2919 static noinline int
2920 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2921                      struct btrfs_free_cluster *cluster,
2922                      struct list_head *bitmaps, u64 offset, u64 bytes,
2923                      u64 cont1_bytes, u64 min_bytes)
2924 {
2925         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2926         struct btrfs_free_space *entry;
2927         int ret = -ENOSPC;
2928         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2929
2930         if (ctl->total_bitmaps == 0)
2931                 return -ENOSPC;
2932
2933         /*
2934          * The bitmap that covers offset won't be in the list unless offset
2935          * is just its start offset.
2936          */
2937         entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2938         if (entry->offset != bitmap_offset) {
2939                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2940                 if (entry && list_empty(&entry->list))
2941                         list_add(&entry->list, bitmaps);
2942         }
2943
2944         list_for_each_entry(entry, bitmaps, list) {
2945                 if (entry->bytes < bytes)
2946                         continue;
2947                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2948                                            bytes, cont1_bytes, min_bytes);
2949                 if (!ret)
2950                         return 0;
2951         }
2952
2953         /*
2954          * The bitmaps list has all the bitmaps that record free space
2955          * starting after offset, so no more search is required.
2956          */
2957         return -ENOSPC;
2958 }
2959
2960 /*
2961  * here we try to find a cluster of blocks in a block group.  The goal
2962  * is to find at least bytes+empty_size.
2963  * We might not find them all in one contiguous area.
2964  *
2965  * returns zero and sets up cluster if things worked out, otherwise
2966  * it returns -enospc
2967  */
2968 int btrfs_find_space_cluster(struct btrfs_root *root,
2969                              struct btrfs_block_group_cache *block_group,
2970                              struct btrfs_free_cluster *cluster,
2971                              u64 offset, u64 bytes, u64 empty_size)
2972 {
2973         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2974         struct btrfs_free_space *entry, *tmp;
2975         LIST_HEAD(bitmaps);
2976         u64 min_bytes;
2977         u64 cont1_bytes;
2978         int ret;
2979
2980         /*
2981          * Choose the minimum extent size we'll require for this
2982          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2983          * For metadata, allow allocates with smaller extents.  For
2984          * data, keep it dense.
2985          */
2986         if (btrfs_test_opt(root, SSD_SPREAD)) {
2987                 cont1_bytes = min_bytes = bytes + empty_size;
2988         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2989                 cont1_bytes = bytes;
2990                 min_bytes = block_group->sectorsize;
2991         } else {
2992                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2993                 min_bytes = block_group->sectorsize;
2994         }
2995
2996         spin_lock(&ctl->tree_lock);
2997
2998         /*
2999          * If we know we don't have enough space to make a cluster don't even
3000          * bother doing all the work to try and find one.
3001          */
3002         if (ctl->free_space < bytes) {
3003                 spin_unlock(&ctl->tree_lock);
3004                 return -ENOSPC;
3005         }
3006
3007         spin_lock(&cluster->lock);
3008
3009         /* someone already found a cluster, hooray */
3010         if (cluster->block_group) {
3011                 ret = 0;
3012                 goto out;
3013         }
3014
3015         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3016                                  min_bytes);
3017
3018         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3019                                       bytes + empty_size,
3020                                       cont1_bytes, min_bytes);
3021         if (ret)
3022                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3023                                            offset, bytes + empty_size,
3024                                            cont1_bytes, min_bytes);
3025
3026         /* Clear our temporary list */
3027         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3028                 list_del_init(&entry->list);
3029
3030         if (!ret) {
3031                 atomic_inc(&block_group->count);
3032                 list_add_tail(&cluster->block_group_list,
3033                               &block_group->cluster_list);
3034                 cluster->block_group = block_group;
3035         } else {
3036                 trace_btrfs_failed_cluster_setup(block_group);
3037         }
3038 out:
3039         spin_unlock(&cluster->lock);
3040         spin_unlock(&ctl->tree_lock);
3041
3042         return ret;
3043 }
3044
3045 /*
3046  * simple code to zero out a cluster
3047  */
3048 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3049 {
3050         spin_lock_init(&cluster->lock);
3051         spin_lock_init(&cluster->refill_lock);
3052         cluster->root = RB_ROOT;
3053         cluster->max_size = 0;
3054         INIT_LIST_HEAD(&cluster->block_group_list);
3055         cluster->block_group = NULL;
3056 }
3057
3058 static int do_trimming(struct btrfs_block_group_cache *block_group,
3059                        u64 *total_trimmed, u64 start, u64 bytes,
3060                        u64 reserved_start, u64 reserved_bytes,
3061                        struct btrfs_trim_range *trim_entry)
3062 {
3063         struct btrfs_space_info *space_info = block_group->space_info;
3064         struct btrfs_fs_info *fs_info = block_group->fs_info;
3065         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3066         int ret;
3067         int update = 0;
3068         u64 trimmed = 0;
3069
3070         spin_lock(&space_info->lock);
3071         spin_lock(&block_group->lock);
3072         if (!block_group->ro) {
3073                 block_group->reserved += reserved_bytes;
3074                 space_info->bytes_reserved += reserved_bytes;
3075                 update = 1;
3076         }
3077         spin_unlock(&block_group->lock);
3078         spin_unlock(&space_info->lock);
3079
3080         ret = btrfs_discard_extent(fs_info->extent_root,
3081                                    start, bytes, &trimmed);
3082         if (!ret)
3083                 *total_trimmed += trimmed;
3084
3085         mutex_lock(&ctl->cache_writeout_mutex);
3086         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
3087         list_del(&trim_entry->list);
3088         mutex_unlock(&ctl->cache_writeout_mutex);
3089
3090         if (update) {
3091                 spin_lock(&space_info->lock);
3092                 spin_lock(&block_group->lock);
3093                 if (block_group->ro)
3094                         space_info->bytes_readonly += reserved_bytes;
3095                 block_group->reserved -= reserved_bytes;
3096                 space_info->bytes_reserved -= reserved_bytes;
3097                 spin_unlock(&space_info->lock);
3098                 spin_unlock(&block_group->lock);
3099         }
3100
3101         return ret;
3102 }
3103
3104 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
3105                           u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3106 {
3107         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3108         struct btrfs_free_space *entry;
3109         struct rb_node *node;
3110         int ret = 0;
3111         u64 extent_start;
3112         u64 extent_bytes;
3113         u64 bytes;
3114
3115         while (start < end) {
3116                 struct btrfs_trim_range trim_entry;
3117
3118                 mutex_lock(&ctl->cache_writeout_mutex);
3119                 spin_lock(&ctl->tree_lock);
3120
3121                 if (ctl->free_space < minlen) {
3122                         spin_unlock(&ctl->tree_lock);
3123                         mutex_unlock(&ctl->cache_writeout_mutex);
3124                         break;
3125                 }
3126
3127                 entry = tree_search_offset(ctl, start, 0, 1);
3128                 if (!entry) {
3129                         spin_unlock(&ctl->tree_lock);
3130                         mutex_unlock(&ctl->cache_writeout_mutex);
3131                         break;
3132                 }
3133
3134                 /* skip bitmaps */
3135                 while (entry->bitmap) {
3136                         node = rb_next(&entry->offset_index);
3137                         if (!node) {
3138                                 spin_unlock(&ctl->tree_lock);
3139                                 mutex_unlock(&ctl->cache_writeout_mutex);
3140                                 goto out;
3141                         }
3142                         entry = rb_entry(node, struct btrfs_free_space,
3143                                          offset_index);
3144                 }
3145
3146                 if (entry->offset >= end) {
3147                         spin_unlock(&ctl->tree_lock);
3148                         mutex_unlock(&ctl->cache_writeout_mutex);
3149                         break;
3150                 }
3151
3152                 extent_start = entry->offset;
3153                 extent_bytes = entry->bytes;
3154                 start = max(start, extent_start);
3155                 bytes = min(extent_start + extent_bytes, end) - start;
3156                 if (bytes < minlen) {
3157                         spin_unlock(&ctl->tree_lock);
3158                         mutex_unlock(&ctl->cache_writeout_mutex);
3159                         goto next;
3160                 }
3161
3162                 unlink_free_space(ctl, entry);
3163                 kmem_cache_free(btrfs_free_space_cachep, entry);
3164
3165                 spin_unlock(&ctl->tree_lock);
3166                 trim_entry.start = extent_start;
3167                 trim_entry.bytes = extent_bytes;
3168                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3169                 mutex_unlock(&ctl->cache_writeout_mutex);
3170
3171                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3172                                   extent_start, extent_bytes, &trim_entry);
3173                 if (ret)
3174                         break;
3175 next:
3176                 start += bytes;
3177
3178                 if (fatal_signal_pending(current)) {
3179                         ret = -ERESTARTSYS;
3180                         break;
3181                 }
3182
3183                 cond_resched();
3184         }
3185 out:
3186         return ret;
3187 }
3188
3189 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
3190                         u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3191 {
3192         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3193         struct btrfs_free_space *entry;
3194         int ret = 0;
3195         int ret2;
3196         u64 bytes;
3197         u64 offset = offset_to_bitmap(ctl, start);
3198
3199         while (offset < end) {
3200                 bool next_bitmap = false;
3201                 struct btrfs_trim_range trim_entry;
3202
3203                 mutex_lock(&ctl->cache_writeout_mutex);
3204                 spin_lock(&ctl->tree_lock);
3205
3206                 if (ctl->free_space < minlen) {
3207                         spin_unlock(&ctl->tree_lock);
3208                         mutex_unlock(&ctl->cache_writeout_mutex);
3209                         break;
3210                 }
3211
3212                 entry = tree_search_offset(ctl, offset, 1, 0);
3213                 if (!entry) {
3214                         spin_unlock(&ctl->tree_lock);
3215                         mutex_unlock(&ctl->cache_writeout_mutex);
3216                         next_bitmap = true;
3217                         goto next;
3218                 }
3219
3220                 bytes = minlen;
3221                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
3222                 if (ret2 || start >= end) {
3223                         spin_unlock(&ctl->tree_lock);
3224                         mutex_unlock(&ctl->cache_writeout_mutex);
3225                         next_bitmap = true;
3226                         goto next;
3227                 }
3228
3229                 bytes = min(bytes, end - start);
3230                 if (bytes < minlen) {
3231                         spin_unlock(&ctl->tree_lock);
3232                         mutex_unlock(&ctl->cache_writeout_mutex);
3233                         goto next;
3234                 }
3235
3236                 bitmap_clear_bits(ctl, entry, start, bytes);
3237                 if (entry->bytes == 0)
3238                         free_bitmap(ctl, entry);
3239
3240                 spin_unlock(&ctl->tree_lock);
3241                 trim_entry.start = start;
3242                 trim_entry.bytes = bytes;
3243                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3244                 mutex_unlock(&ctl->cache_writeout_mutex);
3245
3246                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3247                                   start, bytes, &trim_entry);
3248                 if (ret)
3249                         break;
3250 next:
3251                 if (next_bitmap) {
3252                         offset += BITS_PER_BITMAP * ctl->unit;
3253                 } else {
3254                         start += bytes;
3255                         if (start >= offset + BITS_PER_BITMAP * ctl->unit)
3256                                 offset += BITS_PER_BITMAP * ctl->unit;
3257                 }
3258
3259                 if (fatal_signal_pending(current)) {
3260                         ret = -ERESTARTSYS;
3261                         break;
3262                 }
3263
3264                 cond_resched();
3265         }
3266
3267         return ret;
3268 }
3269
3270 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
3271                            u64 *trimmed, u64 start, u64 end, u64 minlen)
3272 {
3273         int ret;
3274
3275         *trimmed = 0;
3276
3277         spin_lock(&block_group->lock);
3278         if (block_group->removed) {
3279                 spin_unlock(&block_group->lock);
3280                 return 0;
3281         }
3282         atomic_inc(&block_group->trimming);
3283         spin_unlock(&block_group->lock);
3284
3285         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
3286         if (ret)
3287                 goto out;
3288
3289         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
3290 out:
3291         spin_lock(&block_group->lock);
3292         if (atomic_dec_and_test(&block_group->trimming) &&
3293             block_group->removed) {
3294                 struct extent_map_tree *em_tree;
3295                 struct extent_map *em;
3296
3297                 spin_unlock(&block_group->lock);
3298
3299                 lock_chunks(block_group->fs_info->chunk_root);
3300                 em_tree = &block_group->fs_info->mapping_tree.map_tree;
3301                 write_lock(&em_tree->lock);
3302                 em = lookup_extent_mapping(em_tree, block_group->key.objectid,
3303                                            1);
3304                 BUG_ON(!em); /* logic error, can't happen */
3305                 /*
3306                  * remove_extent_mapping() will delete us from the pinned_chunks
3307                  * list, which is protected by the chunk mutex.
3308                  */
3309                 remove_extent_mapping(em_tree, em);
3310                 write_unlock(&em_tree->lock);
3311                 unlock_chunks(block_group->fs_info->chunk_root);
3312
3313                 /* once for us and once for the tree */
3314                 free_extent_map(em);
3315                 free_extent_map(em);
3316
3317                 /*
3318                  * We've left one free space entry and other tasks trimming
3319                  * this block group have left 1 entry each one. Free them.
3320                  */
3321                 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3322         } else {
3323                 spin_unlock(&block_group->lock);
3324         }
3325
3326         return ret;
3327 }
3328
3329 /*
3330  * Find the left-most item in the cache tree, and then return the
3331  * smallest inode number in the item.
3332  *
3333  * Note: the returned inode number may not be the smallest one in
3334  * the tree, if the left-most item is a bitmap.
3335  */
3336 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
3337 {
3338         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
3339         struct btrfs_free_space *entry = NULL;
3340         u64 ino = 0;
3341
3342         spin_lock(&ctl->tree_lock);
3343
3344         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
3345                 goto out;
3346
3347         entry = rb_entry(rb_first(&ctl->free_space_offset),
3348                          struct btrfs_free_space, offset_index);
3349
3350         if (!entry->bitmap) {
3351                 ino = entry->offset;
3352
3353                 unlink_free_space(ctl, entry);
3354                 entry->offset++;
3355                 entry->bytes--;
3356                 if (!entry->bytes)
3357                         kmem_cache_free(btrfs_free_space_cachep, entry);
3358                 else
3359                         link_free_space(ctl, entry);
3360         } else {
3361                 u64 offset = 0;
3362                 u64 count = 1;
3363                 int ret;
3364
3365                 ret = search_bitmap(ctl, entry, &offset, &count);
3366                 /* Logic error; Should be empty if it can't find anything */
3367                 ASSERT(!ret);
3368
3369                 ino = offset;
3370                 bitmap_clear_bits(ctl, entry, offset, 1);
3371                 if (entry->bytes == 0)
3372                         free_bitmap(ctl, entry);
3373         }
3374 out:
3375         spin_unlock(&ctl->tree_lock);
3376
3377         return ino;
3378 }
3379
3380 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3381                                     struct btrfs_path *path)
3382 {
3383         struct inode *inode = NULL;
3384
3385         spin_lock(&root->ino_cache_lock);
3386         if (root->ino_cache_inode)
3387                 inode = igrab(root->ino_cache_inode);
3388         spin_unlock(&root->ino_cache_lock);
3389         if (inode)
3390                 return inode;
3391
3392         inode = __lookup_free_space_inode(root, path, 0);
3393         if (IS_ERR(inode))
3394                 return inode;
3395
3396         spin_lock(&root->ino_cache_lock);
3397         if (!btrfs_fs_closing(root->fs_info))
3398                 root->ino_cache_inode = igrab(inode);
3399         spin_unlock(&root->ino_cache_lock);
3400
3401         return inode;
3402 }
3403
3404 int create_free_ino_inode(struct btrfs_root *root,
3405                           struct btrfs_trans_handle *trans,
3406                           struct btrfs_path *path)
3407 {
3408         return __create_free_space_inode(root, trans, path,
3409                                          BTRFS_FREE_INO_OBJECTID, 0);
3410 }
3411
3412 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3413 {
3414         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3415         struct btrfs_path *path;
3416         struct inode *inode;
3417         int ret = 0;
3418         u64 root_gen = btrfs_root_generation(&root->root_item);
3419
3420         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3421                 return 0;
3422
3423         /*
3424          * If we're unmounting then just return, since this does a search on the
3425          * normal root and not the commit root and we could deadlock.
3426          */
3427         if (btrfs_fs_closing(fs_info))
3428                 return 0;
3429
3430         path = btrfs_alloc_path();
3431         if (!path)
3432                 return 0;
3433
3434         inode = lookup_free_ino_inode(root, path);
3435         if (IS_ERR(inode))
3436                 goto out;
3437
3438         if (root_gen != BTRFS_I(inode)->generation)
3439                 goto out_put;
3440
3441         ret = __load_free_space_cache(root, inode, ctl, path, 0);
3442
3443         if (ret < 0)
3444                 btrfs_err(fs_info,
3445                         "failed to load free ino cache for root %llu",
3446                         root->root_key.objectid);
3447 out_put:
3448         iput(inode);
3449 out:
3450         btrfs_free_path(path);
3451         return ret;
3452 }
3453
3454 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3455                               struct btrfs_trans_handle *trans,
3456                               struct btrfs_path *path,
3457                               struct inode *inode)
3458 {
3459         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3460         int ret;
3461         struct btrfs_io_ctl io_ctl;
3462
3463         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3464                 return 0;
3465
3466         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl,
3467                                       trans, path, 0) ||
3468                 btrfs_wait_cache_io(root, trans, NULL, &io_ctl, path, 0);
3469         if (ret) {
3470                 btrfs_delalloc_release_metadata(inode, inode->i_size);
3471 #ifdef DEBUG
3472                 btrfs_err(root->fs_info,
3473                         "failed to write free ino cache for root %llu",
3474                         root->root_key.objectid);
3475 #endif
3476         }
3477
3478         return ret;
3479 }
3480
3481 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3482 /*
3483  * Use this if you need to make a bitmap or extent entry specifically, it
3484  * doesn't do any of the merging that add_free_space does, this acts a lot like
3485  * how the free space cache loading stuff works, so you can get really weird
3486  * configurations.
3487  */
3488 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3489                               u64 offset, u64 bytes, bool bitmap)
3490 {
3491         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3492         struct btrfs_free_space *info = NULL, *bitmap_info;
3493         void *map = NULL;
3494         u64 bytes_added;
3495         int ret;
3496
3497 again:
3498         if (!info) {
3499                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3500                 if (!info)
3501                         return -ENOMEM;
3502         }
3503
3504         if (!bitmap) {
3505                 spin_lock(&ctl->tree_lock);
3506                 info->offset = offset;
3507                 info->bytes = bytes;
3508                 ret = link_free_space(ctl, info);
3509                 spin_unlock(&ctl->tree_lock);
3510                 if (ret)
3511                         kmem_cache_free(btrfs_free_space_cachep, info);
3512                 return ret;
3513         }
3514
3515         if (!map) {
3516                 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3517                 if (!map) {
3518                         kmem_cache_free(btrfs_free_space_cachep, info);
3519                         return -ENOMEM;
3520                 }
3521         }
3522
3523         spin_lock(&ctl->tree_lock);
3524         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3525                                          1, 0);
3526         if (!bitmap_info) {
3527                 info->bitmap = map;
3528                 map = NULL;
3529                 add_new_bitmap(ctl, info, offset);
3530                 bitmap_info = info;
3531                 info = NULL;
3532         }
3533
3534         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3535         bytes -= bytes_added;
3536         offset += bytes_added;
3537         spin_unlock(&ctl->tree_lock);
3538
3539         if (bytes)
3540                 goto again;
3541
3542         if (info)
3543                 kmem_cache_free(btrfs_free_space_cachep, info);
3544         if (map)
3545                 kfree(map);
3546         return 0;
3547 }
3548
3549 /*
3550  * Checks to see if the given range is in the free space cache.  This is really
3551  * just used to check the absence of space, so if there is free space in the
3552  * range at all we will return 1.
3553  */
3554 int test_check_exists(struct btrfs_block_group_cache *cache,
3555                       u64 offset, u64 bytes)
3556 {
3557         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3558         struct btrfs_free_space *info;
3559         int ret = 0;
3560
3561         spin_lock(&ctl->tree_lock);
3562         info = tree_search_offset(ctl, offset, 0, 0);
3563         if (!info) {
3564                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3565                                           1, 0);
3566                 if (!info)
3567                         goto out;
3568         }
3569
3570 have_info:
3571         if (info->bitmap) {
3572                 u64 bit_off, bit_bytes;
3573                 struct rb_node *n;
3574                 struct btrfs_free_space *tmp;
3575
3576                 bit_off = offset;
3577                 bit_bytes = ctl->unit;
3578                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3579                 if (!ret) {
3580                         if (bit_off == offset) {
3581                                 ret = 1;
3582                                 goto out;
3583                         } else if (bit_off > offset &&
3584                                    offset + bytes > bit_off) {
3585                                 ret = 1;
3586                                 goto out;
3587                         }
3588                 }
3589
3590                 n = rb_prev(&info->offset_index);
3591                 while (n) {
3592                         tmp = rb_entry(n, struct btrfs_free_space,
3593                                        offset_index);
3594                         if (tmp->offset + tmp->bytes < offset)
3595                                 break;
3596                         if (offset + bytes < tmp->offset) {
3597                                 n = rb_prev(&info->offset_index);
3598                                 continue;
3599                         }
3600                         info = tmp;
3601                         goto have_info;
3602                 }
3603
3604                 n = rb_next(&info->offset_index);
3605                 while (n) {
3606                         tmp = rb_entry(n, struct btrfs_free_space,
3607                                        offset_index);
3608                         if (offset + bytes < tmp->offset)
3609                                 break;
3610                         if (tmp->offset + tmp->bytes < offset) {
3611                                 n = rb_next(&info->offset_index);
3612                                 continue;
3613                         }
3614                         info = tmp;
3615                         goto have_info;
3616                 }
3617
3618                 ret = 0;
3619                 goto out;
3620         }
3621
3622         if (info->offset == offset) {
3623                 ret = 1;
3624                 goto out;
3625         }
3626
3627         if (offset > info->offset && offset < info->offset + info->bytes)
3628                 ret = 1;
3629 out:
3630         spin_unlock(&ctl->tree_lock);
3631         return ret;
3632 }
3633 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */