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_FS | __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_bitmap_list(struct list_head *bitmap_list)
1123 {
1124         struct list_head *pos, *n;
1125
1126         list_for_each_safe(pos, n, bitmap_list) {
1127                 struct btrfs_free_space *entry =
1128                         list_entry(pos, struct btrfs_free_space, list);
1129                 list_del_init(&entry->list);
1130         }
1131 }
1132
1133 static void noinline_for_stack
1134 cleanup_write_cache_enospc(struct inode *inode,
1135                            struct btrfs_io_ctl *io_ctl,
1136                            struct extent_state **cached_state,
1137                            struct list_head *bitmap_list)
1138 {
1139         io_ctl_drop_pages(io_ctl);
1140         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1141                              i_size_read(inode) - 1, cached_state,
1142                              GFP_NOFS);
1143 }
1144
1145 int btrfs_wait_cache_io(struct btrfs_root *root,
1146                         struct btrfs_trans_handle *trans,
1147                         struct btrfs_block_group_cache *block_group,
1148                         struct btrfs_io_ctl *io_ctl,
1149                         struct btrfs_path *path, u64 offset)
1150 {
1151         int ret;
1152         struct inode *inode = io_ctl->inode;
1153
1154         if (!inode)
1155                 return 0;
1156
1157         if (block_group)
1158                 root = root->fs_info->tree_root;
1159
1160         /* Flush the dirty pages in the cache file. */
1161         ret = flush_dirty_cache(inode);
1162         if (ret)
1163                 goto out;
1164
1165         /* Update the cache item to tell everyone this cache file is valid. */
1166         ret = update_cache_item(trans, root, inode, path, offset,
1167                                 io_ctl->entries, io_ctl->bitmaps);
1168 out:
1169         io_ctl_free(io_ctl);
1170         if (ret) {
1171                 invalidate_inode_pages2(inode->i_mapping);
1172                 BTRFS_I(inode)->generation = 0;
1173                 if (block_group) {
1174 #ifdef DEBUG
1175                         btrfs_err(root->fs_info,
1176                                 "failed to write free space cache for block group %llu",
1177                                 block_group->key.objectid);
1178 #endif
1179                 }
1180         }
1181         btrfs_update_inode(trans, root, inode);
1182
1183         if (block_group) {
1184                 /* the dirty list is protected by the dirty_bgs_lock */
1185                 spin_lock(&trans->transaction->dirty_bgs_lock);
1186
1187                 /* the disk_cache_state is protected by the block group lock */
1188                 spin_lock(&block_group->lock);
1189
1190                 /*
1191                  * only mark this as written if we didn't get put back on
1192                  * the dirty list while waiting for IO.   Otherwise our
1193                  * cache state won't be right, and we won't get written again
1194                  */
1195                 if (!ret && list_empty(&block_group->dirty_list))
1196                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1197                 else if (ret)
1198                         block_group->disk_cache_state = BTRFS_DC_ERROR;
1199
1200                 spin_unlock(&block_group->lock);
1201                 spin_unlock(&trans->transaction->dirty_bgs_lock);
1202                 io_ctl->inode = NULL;
1203                 iput(inode);
1204         }
1205
1206         return ret;
1207
1208 }
1209
1210 /**
1211  * __btrfs_write_out_cache - write out cached info to an inode
1212  * @root - the root the inode belongs to
1213  * @ctl - the free space cache we are going to write out
1214  * @block_group - the block_group for this cache if it belongs to a block_group
1215  * @trans - the trans handle
1216  * @path - the path to use
1217  * @offset - the offset for the key we'll insert
1218  *
1219  * This function writes out a free space cache struct to disk for quick recovery
1220  * on mount.  This will return 0 if it was successfull in writing the cache out,
1221  * or an errno if it was not.
1222  */
1223 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1224                                    struct btrfs_free_space_ctl *ctl,
1225                                    struct btrfs_block_group_cache *block_group,
1226                                    struct btrfs_io_ctl *io_ctl,
1227                                    struct btrfs_trans_handle *trans,
1228                                    struct btrfs_path *path, u64 offset)
1229 {
1230         struct extent_state *cached_state = NULL;
1231         LIST_HEAD(bitmap_list);
1232         int entries = 0;
1233         int bitmaps = 0;
1234         int ret;
1235         int must_iput = 0;
1236
1237         if (!i_size_read(inode))
1238                 return -EIO;
1239
1240         WARN_ON(io_ctl->pages);
1241         ret = io_ctl_init(io_ctl, inode, root, 1);
1242         if (ret)
1243                 return ret;
1244
1245         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1246                 down_write(&block_group->data_rwsem);
1247                 spin_lock(&block_group->lock);
1248                 if (block_group->delalloc_bytes) {
1249                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1250                         spin_unlock(&block_group->lock);
1251                         up_write(&block_group->data_rwsem);
1252                         BTRFS_I(inode)->generation = 0;
1253                         ret = 0;
1254                         must_iput = 1;
1255                         goto out;
1256                 }
1257                 spin_unlock(&block_group->lock);
1258         }
1259
1260         /* Lock all pages first so we can lock the extent safely. */
1261         ret = io_ctl_prepare_pages(io_ctl, inode, 0);
1262         if (ret)
1263                 goto out;
1264
1265         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1266                          0, &cached_state);
1267
1268         io_ctl_set_generation(io_ctl, trans->transid);
1269
1270         mutex_lock(&ctl->cache_writeout_mutex);
1271         /* Write out the extent entries in the free space cache */
1272         spin_lock(&ctl->tree_lock);
1273         ret = write_cache_extent_entries(io_ctl, ctl,
1274                                          block_group, &entries, &bitmaps,
1275                                          &bitmap_list);
1276         if (ret)
1277                 goto out_nospc_locked;
1278
1279         /*
1280          * Some spaces that are freed in the current transaction are pinned,
1281          * they will be added into free space cache after the transaction is
1282          * committed, we shouldn't lose them.
1283          *
1284          * If this changes while we are working we'll get added back to
1285          * the dirty list and redo it.  No locking needed
1286          */
1287         ret = write_pinned_extent_entries(root, block_group, io_ctl, &entries);
1288         if (ret)
1289                 goto out_nospc_locked;
1290
1291         /*
1292          * At last, we write out all the bitmaps and keep cache_writeout_mutex
1293          * locked while doing it because a concurrent trim can be manipulating
1294          * or freeing the bitmap.
1295          */
1296         ret = write_bitmap_entries(io_ctl, &bitmap_list);
1297         spin_unlock(&ctl->tree_lock);
1298         mutex_unlock(&ctl->cache_writeout_mutex);
1299         if (ret)
1300                 goto out_nospc;
1301
1302         /* Zero out the rest of the pages just to make sure */
1303         io_ctl_zero_remaining_pages(io_ctl);
1304
1305         /* Everything is written out, now we dirty the pages in the file. */
1306         ret = btrfs_dirty_pages(root, inode, io_ctl->pages, io_ctl->num_pages,
1307                                 0, i_size_read(inode), &cached_state);
1308         if (ret)
1309                 goto out_nospc;
1310
1311         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1312                 up_write(&block_group->data_rwsem);
1313         /*
1314          * Release the pages and unlock the extent, we will flush
1315          * them out later
1316          */
1317         io_ctl_drop_pages(io_ctl);
1318
1319         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1320                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1321
1322         /*
1323          * at this point the pages are under IO and we're happy,
1324          * The caller is responsible for waiting on them and updating the
1325          * the cache and the inode
1326          */
1327         io_ctl->entries = entries;
1328         io_ctl->bitmaps = bitmaps;
1329
1330         ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
1331         if (ret)
1332                 goto out;
1333
1334         return 0;
1335
1336 out:
1337         io_ctl->inode = NULL;
1338         io_ctl_free(io_ctl);
1339         if (ret) {
1340                 invalidate_inode_pages2(inode->i_mapping);
1341                 BTRFS_I(inode)->generation = 0;
1342         }
1343         btrfs_update_inode(trans, root, inode);
1344         if (must_iput)
1345                 iput(inode);
1346         return ret;
1347
1348 out_nospc_locked:
1349         cleanup_bitmap_list(&bitmap_list);
1350         spin_unlock(&ctl->tree_lock);
1351         mutex_unlock(&ctl->cache_writeout_mutex);
1352
1353 out_nospc:
1354         cleanup_write_cache_enospc(inode, io_ctl, &cached_state, &bitmap_list);
1355
1356         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1357                 up_write(&block_group->data_rwsem);
1358
1359         goto out;
1360 }
1361
1362 int btrfs_write_out_cache(struct btrfs_root *root,
1363                           struct btrfs_trans_handle *trans,
1364                           struct btrfs_block_group_cache *block_group,
1365                           struct btrfs_path *path)
1366 {
1367         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1368         struct inode *inode;
1369         int ret = 0;
1370
1371         root = root->fs_info->tree_root;
1372
1373         spin_lock(&block_group->lock);
1374         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1375                 spin_unlock(&block_group->lock);
1376                 return 0;
1377         }
1378         spin_unlock(&block_group->lock);
1379
1380         inode = lookup_free_space_inode(root, block_group, path);
1381         if (IS_ERR(inode))
1382                 return 0;
1383
1384         ret = __btrfs_write_out_cache(root, inode, ctl, block_group,
1385                                       &block_group->io_ctl, trans,
1386                                       path, block_group->key.objectid);
1387         if (ret) {
1388 #ifdef DEBUG
1389                 btrfs_err(root->fs_info,
1390                         "failed to write free space cache for block group %llu",
1391                         block_group->key.objectid);
1392 #endif
1393                 spin_lock(&block_group->lock);
1394                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1395                 spin_unlock(&block_group->lock);
1396
1397                 block_group->io_ctl.inode = NULL;
1398                 iput(inode);
1399         }
1400
1401         /*
1402          * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1403          * to wait for IO and put the inode
1404          */
1405
1406         return ret;
1407 }
1408
1409 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1410                                           u64 offset)
1411 {
1412         ASSERT(offset >= bitmap_start);
1413         offset -= bitmap_start;
1414         return (unsigned long)(div_u64(offset, unit));
1415 }
1416
1417 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1418 {
1419         return (unsigned long)(div_u64(bytes, unit));
1420 }
1421
1422 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1423                                    u64 offset)
1424 {
1425         u64 bitmap_start;
1426         u32 bytes_per_bitmap;
1427
1428         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1429         bitmap_start = offset - ctl->start;
1430         bitmap_start = div_u64(bitmap_start, bytes_per_bitmap);
1431         bitmap_start *= bytes_per_bitmap;
1432         bitmap_start += ctl->start;
1433
1434         return bitmap_start;
1435 }
1436
1437 static int tree_insert_offset(struct rb_root *root, u64 offset,
1438                               struct rb_node *node, int bitmap)
1439 {
1440         struct rb_node **p = &root->rb_node;
1441         struct rb_node *parent = NULL;
1442         struct btrfs_free_space *info;
1443
1444         while (*p) {
1445                 parent = *p;
1446                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1447
1448                 if (offset < info->offset) {
1449                         p = &(*p)->rb_left;
1450                 } else if (offset > info->offset) {
1451                         p = &(*p)->rb_right;
1452                 } else {
1453                         /*
1454                          * we could have a bitmap entry and an extent entry
1455                          * share the same offset.  If this is the case, we want
1456                          * the extent entry to always be found first if we do a
1457                          * linear search through the tree, since we want to have
1458                          * the quickest allocation time, and allocating from an
1459                          * extent is faster than allocating from a bitmap.  So
1460                          * if we're inserting a bitmap and we find an entry at
1461                          * this offset, we want to go right, or after this entry
1462                          * logically.  If we are inserting an extent and we've
1463                          * found a bitmap, we want to go left, or before
1464                          * logically.
1465                          */
1466                         if (bitmap) {
1467                                 if (info->bitmap) {
1468                                         WARN_ON_ONCE(1);
1469                                         return -EEXIST;
1470                                 }
1471                                 p = &(*p)->rb_right;
1472                         } else {
1473                                 if (!info->bitmap) {
1474                                         WARN_ON_ONCE(1);
1475                                         return -EEXIST;
1476                                 }
1477                                 p = &(*p)->rb_left;
1478                         }
1479                 }
1480         }
1481
1482         rb_link_node(node, parent, p);
1483         rb_insert_color(node, root);
1484
1485         return 0;
1486 }
1487
1488 /*
1489  * searches the tree for the given offset.
1490  *
1491  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1492  * want a section that has at least bytes size and comes at or after the given
1493  * offset.
1494  */
1495 static struct btrfs_free_space *
1496 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1497                    u64 offset, int bitmap_only, int fuzzy)
1498 {
1499         struct rb_node *n = ctl->free_space_offset.rb_node;
1500         struct btrfs_free_space *entry, *prev = NULL;
1501
1502         /* find entry that is closest to the 'offset' */
1503         while (1) {
1504                 if (!n) {
1505                         entry = NULL;
1506                         break;
1507                 }
1508
1509                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1510                 prev = entry;
1511
1512                 if (offset < entry->offset)
1513                         n = n->rb_left;
1514                 else if (offset > entry->offset)
1515                         n = n->rb_right;
1516                 else
1517                         break;
1518         }
1519
1520         if (bitmap_only) {
1521                 if (!entry)
1522                         return NULL;
1523                 if (entry->bitmap)
1524                         return entry;
1525
1526                 /*
1527                  * bitmap entry and extent entry may share same offset,
1528                  * in that case, bitmap entry comes after extent entry.
1529                  */
1530                 n = rb_next(n);
1531                 if (!n)
1532                         return NULL;
1533                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1534                 if (entry->offset != offset)
1535                         return NULL;
1536
1537                 WARN_ON(!entry->bitmap);
1538                 return entry;
1539         } else if (entry) {
1540                 if (entry->bitmap) {
1541                         /*
1542                          * if previous extent entry covers the offset,
1543                          * we should return it instead of the bitmap entry
1544                          */
1545                         n = rb_prev(&entry->offset_index);
1546                         if (n) {
1547                                 prev = rb_entry(n, struct btrfs_free_space,
1548                                                 offset_index);
1549                                 if (!prev->bitmap &&
1550                                     prev->offset + prev->bytes > offset)
1551                                         entry = prev;
1552                         }
1553                 }
1554                 return entry;
1555         }
1556
1557         if (!prev)
1558                 return NULL;
1559
1560         /* find last entry before the 'offset' */
1561         entry = prev;
1562         if (entry->offset > offset) {
1563                 n = rb_prev(&entry->offset_index);
1564                 if (n) {
1565                         entry = rb_entry(n, struct btrfs_free_space,
1566                                         offset_index);
1567                         ASSERT(entry->offset <= offset);
1568                 } else {
1569                         if (fuzzy)
1570                                 return entry;
1571                         else
1572                                 return NULL;
1573                 }
1574         }
1575
1576         if (entry->bitmap) {
1577                 n = rb_prev(&entry->offset_index);
1578                 if (n) {
1579                         prev = rb_entry(n, struct btrfs_free_space,
1580                                         offset_index);
1581                         if (!prev->bitmap &&
1582                             prev->offset + prev->bytes > offset)
1583                                 return prev;
1584                 }
1585                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1586                         return entry;
1587         } else if (entry->offset + entry->bytes > offset)
1588                 return entry;
1589
1590         if (!fuzzy)
1591                 return NULL;
1592
1593         while (1) {
1594                 if (entry->bitmap) {
1595                         if (entry->offset + BITS_PER_BITMAP *
1596                             ctl->unit > offset)
1597                                 break;
1598                 } else {
1599                         if (entry->offset + entry->bytes > offset)
1600                                 break;
1601                 }
1602
1603                 n = rb_next(&entry->offset_index);
1604                 if (!n)
1605                         return NULL;
1606                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1607         }
1608         return entry;
1609 }
1610
1611 static inline void
1612 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1613                     struct btrfs_free_space *info)
1614 {
1615         rb_erase(&info->offset_index, &ctl->free_space_offset);
1616         ctl->free_extents--;
1617 }
1618
1619 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1620                               struct btrfs_free_space *info)
1621 {
1622         __unlink_free_space(ctl, info);
1623         ctl->free_space -= info->bytes;
1624 }
1625
1626 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1627                            struct btrfs_free_space *info)
1628 {
1629         int ret = 0;
1630
1631         ASSERT(info->bytes || info->bitmap);
1632         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1633                                  &info->offset_index, (info->bitmap != NULL));
1634         if (ret)
1635                 return ret;
1636
1637         ctl->free_space += info->bytes;
1638         ctl->free_extents++;
1639         return ret;
1640 }
1641
1642 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1643 {
1644         struct btrfs_block_group_cache *block_group = ctl->private;
1645         u64 max_bytes;
1646         u64 bitmap_bytes;
1647         u64 extent_bytes;
1648         u64 size = block_group->key.offset;
1649         u32 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1650         u32 max_bitmaps = div_u64(size + bytes_per_bg - 1, bytes_per_bg);
1651
1652         max_bitmaps = max_t(u32, max_bitmaps, 1);
1653
1654         ASSERT(ctl->total_bitmaps <= max_bitmaps);
1655
1656         /*
1657          * The goal is to keep the total amount of memory used per 1gb of space
1658          * at or below 32k, so we need to adjust how much memory we allow to be
1659          * used by extent based free space tracking
1660          */
1661         if (size < 1024 * 1024 * 1024)
1662                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1663         else
1664                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1665                         div_u64(size, 1024 * 1024 * 1024);
1666
1667         /*
1668          * we want to account for 1 more bitmap than what we have so we can make
1669          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1670          * we add more bitmaps.
1671          */
1672         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1673
1674         if (bitmap_bytes >= max_bytes) {
1675                 ctl->extents_thresh = 0;
1676                 return;
1677         }
1678
1679         /*
1680          * we want the extent entry threshold to always be at most 1/2 the max
1681          * bytes we can have, or whatever is less than that.
1682          */
1683         extent_bytes = max_bytes - bitmap_bytes;
1684         extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
1685
1686         ctl->extents_thresh =
1687                 div_u64(extent_bytes, sizeof(struct btrfs_free_space));
1688 }
1689
1690 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1691                                        struct btrfs_free_space *info,
1692                                        u64 offset, u64 bytes)
1693 {
1694         unsigned long start, count;
1695
1696         start = offset_to_bit(info->offset, ctl->unit, offset);
1697         count = bytes_to_bits(bytes, ctl->unit);
1698         ASSERT(start + count <= BITS_PER_BITMAP);
1699
1700         bitmap_clear(info->bitmap, start, count);
1701
1702         info->bytes -= bytes;
1703 }
1704
1705 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1706                               struct btrfs_free_space *info, u64 offset,
1707                               u64 bytes)
1708 {
1709         __bitmap_clear_bits(ctl, info, offset, bytes);
1710         ctl->free_space -= bytes;
1711 }
1712
1713 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1714                             struct btrfs_free_space *info, u64 offset,
1715                             u64 bytes)
1716 {
1717         unsigned long start, count;
1718
1719         start = offset_to_bit(info->offset, ctl->unit, offset);
1720         count = bytes_to_bits(bytes, ctl->unit);
1721         ASSERT(start + count <= BITS_PER_BITMAP);
1722
1723         bitmap_set(info->bitmap, start, count);
1724
1725         info->bytes += bytes;
1726         ctl->free_space += bytes;
1727 }
1728
1729 /*
1730  * If we can not find suitable extent, we will use bytes to record
1731  * the size of the max extent.
1732  */
1733 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1734                          struct btrfs_free_space *bitmap_info, u64 *offset,
1735                          u64 *bytes)
1736 {
1737         unsigned long found_bits = 0;
1738         unsigned long max_bits = 0;
1739         unsigned long bits, i;
1740         unsigned long next_zero;
1741         unsigned long extent_bits;
1742
1743         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1744                           max_t(u64, *offset, bitmap_info->offset));
1745         bits = bytes_to_bits(*bytes, ctl->unit);
1746
1747         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1748                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1749                                                BITS_PER_BITMAP, i);
1750                 extent_bits = next_zero - i;
1751                 if (extent_bits >= bits) {
1752                         found_bits = extent_bits;
1753                         break;
1754                 } else if (extent_bits > max_bits) {
1755                         max_bits = extent_bits;
1756                 }
1757                 i = next_zero;
1758         }
1759
1760         if (found_bits) {
1761                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1762                 *bytes = (u64)(found_bits) * ctl->unit;
1763                 return 0;
1764         }
1765
1766         *bytes = (u64)(max_bits) * ctl->unit;
1767         return -1;
1768 }
1769
1770 /* Cache the size of the max extent in bytes */
1771 static struct btrfs_free_space *
1772 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1773                 unsigned long align, u64 *max_extent_size)
1774 {
1775         struct btrfs_free_space *entry;
1776         struct rb_node *node;
1777         u64 tmp;
1778         u64 align_off;
1779         int ret;
1780
1781         if (!ctl->free_space_offset.rb_node)
1782                 goto out;
1783
1784         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1785         if (!entry)
1786                 goto out;
1787
1788         for (node = &entry->offset_index; node; node = rb_next(node)) {
1789                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1790                 if (entry->bytes < *bytes) {
1791                         if (entry->bytes > *max_extent_size)
1792                                 *max_extent_size = entry->bytes;
1793                         continue;
1794                 }
1795
1796                 /* make sure the space returned is big enough
1797                  * to match our requested alignment
1798                  */
1799                 if (*bytes >= align) {
1800                         tmp = entry->offset - ctl->start + align - 1;
1801                         tmp = div64_u64(tmp, align);
1802                         tmp = tmp * align + ctl->start;
1803                         align_off = tmp - entry->offset;
1804                 } else {
1805                         align_off = 0;
1806                         tmp = entry->offset;
1807                 }
1808
1809                 if (entry->bytes < *bytes + align_off) {
1810                         if (entry->bytes > *max_extent_size)
1811                                 *max_extent_size = entry->bytes;
1812                         continue;
1813                 }
1814
1815                 if (entry->bitmap) {
1816                         u64 size = *bytes;
1817
1818                         ret = search_bitmap(ctl, entry, &tmp, &size);
1819                         if (!ret) {
1820                                 *offset = tmp;
1821                                 *bytes = size;
1822                                 return entry;
1823                         } else if (size > *max_extent_size) {
1824                                 *max_extent_size = size;
1825                         }
1826                         continue;
1827                 }
1828
1829                 *offset = tmp;
1830                 *bytes = entry->bytes - align_off;
1831                 return entry;
1832         }
1833 out:
1834         return NULL;
1835 }
1836
1837 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1838                            struct btrfs_free_space *info, u64 offset)
1839 {
1840         info->offset = offset_to_bitmap(ctl, offset);
1841         info->bytes = 0;
1842         INIT_LIST_HEAD(&info->list);
1843         link_free_space(ctl, info);
1844         ctl->total_bitmaps++;
1845
1846         ctl->op->recalc_thresholds(ctl);
1847 }
1848
1849 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1850                         struct btrfs_free_space *bitmap_info)
1851 {
1852         unlink_free_space(ctl, bitmap_info);
1853         kfree(bitmap_info->bitmap);
1854         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1855         ctl->total_bitmaps--;
1856         ctl->op->recalc_thresholds(ctl);
1857 }
1858
1859 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1860                               struct btrfs_free_space *bitmap_info,
1861                               u64 *offset, u64 *bytes)
1862 {
1863         u64 end;
1864         u64 search_start, search_bytes;
1865         int ret;
1866
1867 again:
1868         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1869
1870         /*
1871          * We need to search for bits in this bitmap.  We could only cover some
1872          * of the extent in this bitmap thanks to how we add space, so we need
1873          * to search for as much as it as we can and clear that amount, and then
1874          * go searching for the next bit.
1875          */
1876         search_start = *offset;
1877         search_bytes = ctl->unit;
1878         search_bytes = min(search_bytes, end - search_start + 1);
1879         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1880         if (ret < 0 || search_start != *offset)
1881                 return -EINVAL;
1882
1883         /* We may have found more bits than what we need */
1884         search_bytes = min(search_bytes, *bytes);
1885
1886         /* Cannot clear past the end of the bitmap */
1887         search_bytes = min(search_bytes, end - search_start + 1);
1888
1889         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1890         *offset += search_bytes;
1891         *bytes -= search_bytes;
1892
1893         if (*bytes) {
1894                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1895                 if (!bitmap_info->bytes)
1896                         free_bitmap(ctl, bitmap_info);
1897
1898                 /*
1899                  * no entry after this bitmap, but we still have bytes to
1900                  * remove, so something has gone wrong.
1901                  */
1902                 if (!next)
1903                         return -EINVAL;
1904
1905                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1906                                        offset_index);
1907
1908                 /*
1909                  * if the next entry isn't a bitmap we need to return to let the
1910                  * extent stuff do its work.
1911                  */
1912                 if (!bitmap_info->bitmap)
1913                         return -EAGAIN;
1914
1915                 /*
1916                  * Ok the next item is a bitmap, but it may not actually hold
1917                  * the information for the rest of this free space stuff, so
1918                  * look for it, and if we don't find it return so we can try
1919                  * everything over again.
1920                  */
1921                 search_start = *offset;
1922                 search_bytes = ctl->unit;
1923                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1924                                     &search_bytes);
1925                 if (ret < 0 || search_start != *offset)
1926                         return -EAGAIN;
1927
1928                 goto again;
1929         } else if (!bitmap_info->bytes)
1930                 free_bitmap(ctl, bitmap_info);
1931
1932         return 0;
1933 }
1934
1935 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1936                                struct btrfs_free_space *info, u64 offset,
1937                                u64 bytes)
1938 {
1939         u64 bytes_to_set = 0;
1940         u64 end;
1941
1942         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1943
1944         bytes_to_set = min(end - offset, bytes);
1945
1946         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1947
1948         return bytes_to_set;
1949
1950 }
1951
1952 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1953                       struct btrfs_free_space *info)
1954 {
1955         struct btrfs_block_group_cache *block_group = ctl->private;
1956
1957         /*
1958          * If we are below the extents threshold then we can add this as an
1959          * extent, and don't have to deal with the bitmap
1960          */
1961         if (ctl->free_extents < ctl->extents_thresh) {
1962                 /*
1963                  * If this block group has some small extents we don't want to
1964                  * use up all of our free slots in the cache with them, we want
1965                  * to reserve them to larger extents, however if we have plent
1966                  * of cache left then go ahead an dadd them, no sense in adding
1967                  * the overhead of a bitmap if we don't have to.
1968                  */
1969                 if (info->bytes <= block_group->sectorsize * 4) {
1970                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1971                                 return false;
1972                 } else {
1973                         return false;
1974                 }
1975         }
1976
1977         /*
1978          * The original block groups from mkfs can be really small, like 8
1979          * megabytes, so don't bother with a bitmap for those entries.  However
1980          * some block groups can be smaller than what a bitmap would cover but
1981          * are still large enough that they could overflow the 32k memory limit,
1982          * so allow those block groups to still be allowed to have a bitmap
1983          * entry.
1984          */
1985         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1986                 return false;
1987
1988         return true;
1989 }
1990
1991 static struct btrfs_free_space_op free_space_op = {
1992         .recalc_thresholds      = recalculate_thresholds,
1993         .use_bitmap             = use_bitmap,
1994 };
1995
1996 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1997                               struct btrfs_free_space *info)
1998 {
1999         struct btrfs_free_space *bitmap_info;
2000         struct btrfs_block_group_cache *block_group = NULL;
2001         int added = 0;
2002         u64 bytes, offset, bytes_added;
2003         int ret;
2004
2005         bytes = info->bytes;
2006         offset = info->offset;
2007
2008         if (!ctl->op->use_bitmap(ctl, info))
2009                 return 0;
2010
2011         if (ctl->op == &free_space_op)
2012                 block_group = ctl->private;
2013 again:
2014         /*
2015          * Since we link bitmaps right into the cluster we need to see if we
2016          * have a cluster here, and if so and it has our bitmap we need to add
2017          * the free space to that bitmap.
2018          */
2019         if (block_group && !list_empty(&block_group->cluster_list)) {
2020                 struct btrfs_free_cluster *cluster;
2021                 struct rb_node *node;
2022                 struct btrfs_free_space *entry;
2023
2024                 cluster = list_entry(block_group->cluster_list.next,
2025                                      struct btrfs_free_cluster,
2026                                      block_group_list);
2027                 spin_lock(&cluster->lock);
2028                 node = rb_first(&cluster->root);
2029                 if (!node) {
2030                         spin_unlock(&cluster->lock);
2031                         goto no_cluster_bitmap;
2032                 }
2033
2034                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2035                 if (!entry->bitmap) {
2036                         spin_unlock(&cluster->lock);
2037                         goto no_cluster_bitmap;
2038                 }
2039
2040                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
2041                         bytes_added = add_bytes_to_bitmap(ctl, entry,
2042                                                           offset, bytes);
2043                         bytes -= bytes_added;
2044                         offset += bytes_added;
2045                 }
2046                 spin_unlock(&cluster->lock);
2047                 if (!bytes) {
2048                         ret = 1;
2049                         goto out;
2050                 }
2051         }
2052
2053 no_cluster_bitmap:
2054         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2055                                          1, 0);
2056         if (!bitmap_info) {
2057                 ASSERT(added == 0);
2058                 goto new_bitmap;
2059         }
2060
2061         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
2062         bytes -= bytes_added;
2063         offset += bytes_added;
2064         added = 0;
2065
2066         if (!bytes) {
2067                 ret = 1;
2068                 goto out;
2069         } else
2070                 goto again;
2071
2072 new_bitmap:
2073         if (info && info->bitmap) {
2074                 add_new_bitmap(ctl, info, offset);
2075                 added = 1;
2076                 info = NULL;
2077                 goto again;
2078         } else {
2079                 spin_unlock(&ctl->tree_lock);
2080
2081                 /* no pre-allocated info, allocate a new one */
2082                 if (!info) {
2083                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
2084                                                  GFP_NOFS);
2085                         if (!info) {
2086                                 spin_lock(&ctl->tree_lock);
2087                                 ret = -ENOMEM;
2088                                 goto out;
2089                         }
2090                 }
2091
2092                 /* allocate the bitmap */
2093                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
2094                 spin_lock(&ctl->tree_lock);
2095                 if (!info->bitmap) {
2096                         ret = -ENOMEM;
2097                         goto out;
2098                 }
2099                 goto again;
2100         }
2101
2102 out:
2103         if (info) {
2104                 if (info->bitmap)
2105                         kfree(info->bitmap);
2106                 kmem_cache_free(btrfs_free_space_cachep, info);
2107         }
2108
2109         return ret;
2110 }
2111
2112 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2113                           struct btrfs_free_space *info, bool update_stat)
2114 {
2115         struct btrfs_free_space *left_info;
2116         struct btrfs_free_space *right_info;
2117         bool merged = false;
2118         u64 offset = info->offset;
2119         u64 bytes = info->bytes;
2120
2121         /*
2122          * first we want to see if there is free space adjacent to the range we
2123          * are adding, if there is remove that struct and add a new one to
2124          * cover the entire range
2125          */
2126         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2127         if (right_info && rb_prev(&right_info->offset_index))
2128                 left_info = rb_entry(rb_prev(&right_info->offset_index),
2129                                      struct btrfs_free_space, offset_index);
2130         else
2131                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2132
2133         if (right_info && !right_info->bitmap) {
2134                 if (update_stat)
2135                         unlink_free_space(ctl, right_info);
2136                 else
2137                         __unlink_free_space(ctl, right_info);
2138                 info->bytes += right_info->bytes;
2139                 kmem_cache_free(btrfs_free_space_cachep, right_info);
2140                 merged = true;
2141         }
2142
2143         if (left_info && !left_info->bitmap &&
2144             left_info->offset + left_info->bytes == offset) {
2145                 if (update_stat)
2146                         unlink_free_space(ctl, left_info);
2147                 else
2148                         __unlink_free_space(ctl, left_info);
2149                 info->offset = left_info->offset;
2150                 info->bytes += left_info->bytes;
2151                 kmem_cache_free(btrfs_free_space_cachep, left_info);
2152                 merged = true;
2153         }
2154
2155         return merged;
2156 }
2157
2158 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2159                                      struct btrfs_free_space *info,
2160                                      bool update_stat)
2161 {
2162         struct btrfs_free_space *bitmap;
2163         unsigned long i;
2164         unsigned long j;
2165         const u64 end = info->offset + info->bytes;
2166         const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2167         u64 bytes;
2168
2169         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2170         if (!bitmap)
2171                 return false;
2172
2173         i = offset_to_bit(bitmap->offset, ctl->unit, end);
2174         j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2175         if (j == i)
2176                 return false;
2177         bytes = (j - i) * ctl->unit;
2178         info->bytes += bytes;
2179
2180         if (update_stat)
2181                 bitmap_clear_bits(ctl, bitmap, end, bytes);
2182         else
2183                 __bitmap_clear_bits(ctl, bitmap, end, bytes);
2184
2185         if (!bitmap->bytes)
2186                 free_bitmap(ctl, bitmap);
2187
2188         return true;
2189 }
2190
2191 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2192                                        struct btrfs_free_space *info,
2193                                        bool update_stat)
2194 {
2195         struct btrfs_free_space *bitmap;
2196         u64 bitmap_offset;
2197         unsigned long i;
2198         unsigned long j;
2199         unsigned long prev_j;
2200         u64 bytes;
2201
2202         bitmap_offset = offset_to_bitmap(ctl, info->offset);
2203         /* If we're on a boundary, try the previous logical bitmap. */
2204         if (bitmap_offset == info->offset) {
2205                 if (info->offset == 0)
2206                         return false;
2207                 bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2208         }
2209
2210         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2211         if (!bitmap)
2212                 return false;
2213
2214         i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2215         j = 0;
2216         prev_j = (unsigned long)-1;
2217         for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2218                 if (j > i)
2219                         break;
2220                 prev_j = j;
2221         }
2222         if (prev_j == i)
2223                 return false;
2224
2225         if (prev_j == (unsigned long)-1)
2226                 bytes = (i + 1) * ctl->unit;
2227         else
2228                 bytes = (i - prev_j) * ctl->unit;
2229
2230         info->offset -= bytes;
2231         info->bytes += bytes;
2232
2233         if (update_stat)
2234                 bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2235         else
2236                 __bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2237
2238         if (!bitmap->bytes)
2239                 free_bitmap(ctl, bitmap);
2240
2241         return true;
2242 }
2243
2244 /*
2245  * We prefer always to allocate from extent entries, both for clustered and
2246  * non-clustered allocation requests. So when attempting to add a new extent
2247  * entry, try to see if there's adjacent free space in bitmap entries, and if
2248  * there is, migrate that space from the bitmaps to the extent.
2249  * Like this we get better chances of satisfying space allocation requests
2250  * because we attempt to satisfy them based on a single cache entry, and never
2251  * on 2 or more entries - even if the entries represent a contiguous free space
2252  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2253  * ends).
2254  */
2255 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2256                               struct btrfs_free_space *info,
2257                               bool update_stat)
2258 {
2259         /*
2260          * Only work with disconnected entries, as we can change their offset,
2261          * and must be extent entries.
2262          */
2263         ASSERT(!info->bitmap);
2264         ASSERT(RB_EMPTY_NODE(&info->offset_index));
2265
2266         if (ctl->total_bitmaps > 0) {
2267                 bool stole_end;
2268                 bool stole_front = false;
2269
2270                 stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2271                 if (ctl->total_bitmaps > 0)
2272                         stole_front = steal_from_bitmap_to_front(ctl, info,
2273                                                                  update_stat);
2274
2275                 if (stole_end || stole_front)
2276                         try_merge_free_space(ctl, info, update_stat);
2277         }
2278 }
2279
2280 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
2281                            u64 offset, u64 bytes)
2282 {
2283         struct btrfs_free_space *info;
2284         int ret = 0;
2285
2286         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2287         if (!info)
2288                 return -ENOMEM;
2289
2290         info->offset = offset;
2291         info->bytes = bytes;
2292         RB_CLEAR_NODE(&info->offset_index);
2293
2294         spin_lock(&ctl->tree_lock);
2295
2296         if (try_merge_free_space(ctl, info, true))
2297                 goto link;
2298
2299         /*
2300          * There was no extent directly to the left or right of this new
2301          * extent then we know we're going to have to allocate a new extent, so
2302          * before we do that see if we need to drop this into a bitmap
2303          */
2304         ret = insert_into_bitmap(ctl, info);
2305         if (ret < 0) {
2306                 goto out;
2307         } else if (ret) {
2308                 ret = 0;
2309                 goto out;
2310         }
2311 link:
2312         /*
2313          * Only steal free space from adjacent bitmaps if we're sure we're not
2314          * going to add the new free space to existing bitmap entries - because
2315          * that would mean unnecessary work that would be reverted. Therefore
2316          * attempt to steal space from bitmaps if we're adding an extent entry.
2317          */
2318         steal_from_bitmap(ctl, info, true);
2319
2320         ret = link_free_space(ctl, info);
2321         if (ret)
2322                 kmem_cache_free(btrfs_free_space_cachep, info);
2323 out:
2324         spin_unlock(&ctl->tree_lock);
2325
2326         if (ret) {
2327                 printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2328                 ASSERT(ret != -EEXIST);
2329         }
2330
2331         return ret;
2332 }
2333
2334 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2335                             u64 offset, u64 bytes)
2336 {
2337         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2338         struct btrfs_free_space *info;
2339         int ret;
2340         bool re_search = false;
2341
2342         spin_lock(&ctl->tree_lock);
2343
2344 again:
2345         ret = 0;
2346         if (!bytes)
2347                 goto out_lock;
2348
2349         info = tree_search_offset(ctl, offset, 0, 0);
2350         if (!info) {
2351                 /*
2352                  * oops didn't find an extent that matched the space we wanted
2353                  * to remove, look for a bitmap instead
2354                  */
2355                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2356                                           1, 0);
2357                 if (!info) {
2358                         /*
2359                          * If we found a partial bit of our free space in a
2360                          * bitmap but then couldn't find the other part this may
2361                          * be a problem, so WARN about it.
2362                          */
2363                         WARN_ON(re_search);
2364                         goto out_lock;
2365                 }
2366         }
2367
2368         re_search = false;
2369         if (!info->bitmap) {
2370                 unlink_free_space(ctl, info);
2371                 if (offset == info->offset) {
2372                         u64 to_free = min(bytes, info->bytes);
2373
2374                         info->bytes -= to_free;
2375                         info->offset += to_free;
2376                         if (info->bytes) {
2377                                 ret = link_free_space(ctl, info);
2378                                 WARN_ON(ret);
2379                         } else {
2380                                 kmem_cache_free(btrfs_free_space_cachep, info);
2381                         }
2382
2383                         offset += to_free;
2384                         bytes -= to_free;
2385                         goto again;
2386                 } else {
2387                         u64 old_end = info->bytes + info->offset;
2388
2389                         info->bytes = offset - info->offset;
2390                         ret = link_free_space(ctl, info);
2391                         WARN_ON(ret);
2392                         if (ret)
2393                                 goto out_lock;
2394
2395                         /* Not enough bytes in this entry to satisfy us */
2396                         if (old_end < offset + bytes) {
2397                                 bytes -= old_end - offset;
2398                                 offset = old_end;
2399                                 goto again;
2400                         } else if (old_end == offset + bytes) {
2401                                 /* all done */
2402                                 goto out_lock;
2403                         }
2404                         spin_unlock(&ctl->tree_lock);
2405
2406                         ret = btrfs_add_free_space(block_group, offset + bytes,
2407                                                    old_end - (offset + bytes));
2408                         WARN_ON(ret);
2409                         goto out;
2410                 }
2411         }
2412
2413         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2414         if (ret == -EAGAIN) {
2415                 re_search = true;
2416                 goto again;
2417         }
2418 out_lock:
2419         spin_unlock(&ctl->tree_lock);
2420 out:
2421         return ret;
2422 }
2423
2424 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2425                            u64 bytes)
2426 {
2427         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2428         struct btrfs_free_space *info;
2429         struct rb_node *n;
2430         int count = 0;
2431
2432         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2433                 info = rb_entry(n, struct btrfs_free_space, offset_index);
2434                 if (info->bytes >= bytes && !block_group->ro)
2435                         count++;
2436                 btrfs_crit(block_group->fs_info,
2437                            "entry offset %llu, bytes %llu, bitmap %s",
2438                            info->offset, info->bytes,
2439                        (info->bitmap) ? "yes" : "no");
2440         }
2441         btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2442                list_empty(&block_group->cluster_list) ? "no" : "yes");
2443         btrfs_info(block_group->fs_info,
2444                    "%d blocks of free space at or bigger than bytes is", count);
2445 }
2446
2447 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2448 {
2449         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2450
2451         spin_lock_init(&ctl->tree_lock);
2452         ctl->unit = block_group->sectorsize;
2453         ctl->start = block_group->key.objectid;
2454         ctl->private = block_group;
2455         ctl->op = &free_space_op;
2456         INIT_LIST_HEAD(&ctl->trimming_ranges);
2457         mutex_init(&ctl->cache_writeout_mutex);
2458
2459         /*
2460          * we only want to have 32k of ram per block group for keeping
2461          * track of free space, and if we pass 1/2 of that we want to
2462          * start converting things over to using bitmaps
2463          */
2464         ctl->extents_thresh = ((1024 * 32) / 2) /
2465                                 sizeof(struct btrfs_free_space);
2466 }
2467
2468 /*
2469  * for a given cluster, put all of its extents back into the free
2470  * space cache.  If the block group passed doesn't match the block group
2471  * pointed to by the cluster, someone else raced in and freed the
2472  * cluster already.  In that case, we just return without changing anything
2473  */
2474 static int
2475 __btrfs_return_cluster_to_free_space(
2476                              struct btrfs_block_group_cache *block_group,
2477                              struct btrfs_free_cluster *cluster)
2478 {
2479         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2480         struct btrfs_free_space *entry;
2481         struct rb_node *node;
2482
2483         spin_lock(&cluster->lock);
2484         if (cluster->block_group != block_group)
2485                 goto out;
2486
2487         cluster->block_group = NULL;
2488         cluster->window_start = 0;
2489         list_del_init(&cluster->block_group_list);
2490
2491         node = rb_first(&cluster->root);
2492         while (node) {
2493                 bool bitmap;
2494
2495                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2496                 node = rb_next(&entry->offset_index);
2497                 rb_erase(&entry->offset_index, &cluster->root);
2498                 RB_CLEAR_NODE(&entry->offset_index);
2499
2500                 bitmap = (entry->bitmap != NULL);
2501                 if (!bitmap) {
2502                         try_merge_free_space(ctl, entry, false);
2503                         steal_from_bitmap(ctl, entry, false);
2504                 }
2505                 tree_insert_offset(&ctl->free_space_offset,
2506                                    entry->offset, &entry->offset_index, bitmap);
2507         }
2508         cluster->root = RB_ROOT;
2509
2510 out:
2511         spin_unlock(&cluster->lock);
2512         btrfs_put_block_group(block_group);
2513         return 0;
2514 }
2515
2516 static void __btrfs_remove_free_space_cache_locked(
2517                                 struct btrfs_free_space_ctl *ctl)
2518 {
2519         struct btrfs_free_space *info;
2520         struct rb_node *node;
2521
2522         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2523                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2524                 if (!info->bitmap) {
2525                         unlink_free_space(ctl, info);
2526                         kmem_cache_free(btrfs_free_space_cachep, info);
2527                 } else {
2528                         free_bitmap(ctl, info);
2529                 }
2530
2531                 cond_resched_lock(&ctl->tree_lock);
2532         }
2533 }
2534
2535 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2536 {
2537         spin_lock(&ctl->tree_lock);
2538         __btrfs_remove_free_space_cache_locked(ctl);
2539         spin_unlock(&ctl->tree_lock);
2540 }
2541
2542 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2543 {
2544         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2545         struct btrfs_free_cluster *cluster;
2546         struct list_head *head;
2547
2548         spin_lock(&ctl->tree_lock);
2549         while ((head = block_group->cluster_list.next) !=
2550                &block_group->cluster_list) {
2551                 cluster = list_entry(head, struct btrfs_free_cluster,
2552                                      block_group_list);
2553
2554                 WARN_ON(cluster->block_group != block_group);
2555                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2556
2557                 cond_resched_lock(&ctl->tree_lock);
2558         }
2559         __btrfs_remove_free_space_cache_locked(ctl);
2560         spin_unlock(&ctl->tree_lock);
2561
2562 }
2563
2564 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2565                                u64 offset, u64 bytes, u64 empty_size,
2566                                u64 *max_extent_size)
2567 {
2568         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2569         struct btrfs_free_space *entry = NULL;
2570         u64 bytes_search = bytes + empty_size;
2571         u64 ret = 0;
2572         u64 align_gap = 0;
2573         u64 align_gap_len = 0;
2574
2575         spin_lock(&ctl->tree_lock);
2576         entry = find_free_space(ctl, &offset, &bytes_search,
2577                                 block_group->full_stripe_len, max_extent_size);
2578         if (!entry)
2579                 goto out;
2580
2581         ret = offset;
2582         if (entry->bitmap) {
2583                 bitmap_clear_bits(ctl, entry, offset, bytes);
2584                 if (!entry->bytes)
2585                         free_bitmap(ctl, entry);
2586         } else {
2587                 unlink_free_space(ctl, entry);
2588                 align_gap_len = offset - entry->offset;
2589                 align_gap = entry->offset;
2590
2591                 entry->offset = offset + bytes;
2592                 WARN_ON(entry->bytes < bytes + align_gap_len);
2593
2594                 entry->bytes -= bytes + align_gap_len;
2595                 if (!entry->bytes)
2596                         kmem_cache_free(btrfs_free_space_cachep, entry);
2597                 else
2598                         link_free_space(ctl, entry);
2599         }
2600 out:
2601         spin_unlock(&ctl->tree_lock);
2602
2603         if (align_gap_len)
2604                 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2605         return ret;
2606 }
2607
2608 /*
2609  * given a cluster, put all of its extents back into the free space
2610  * cache.  If a block group is passed, this function will only free
2611  * a cluster that belongs to the passed block group.
2612  *
2613  * Otherwise, it'll get a reference on the block group pointed to by the
2614  * cluster and remove the cluster from it.
2615  */
2616 int btrfs_return_cluster_to_free_space(
2617                                struct btrfs_block_group_cache *block_group,
2618                                struct btrfs_free_cluster *cluster)
2619 {
2620         struct btrfs_free_space_ctl *ctl;
2621         int ret;
2622
2623         /* first, get a safe pointer to the block group */
2624         spin_lock(&cluster->lock);
2625         if (!block_group) {
2626                 block_group = cluster->block_group;
2627                 if (!block_group) {
2628                         spin_unlock(&cluster->lock);
2629                         return 0;
2630                 }
2631         } else if (cluster->block_group != block_group) {
2632                 /* someone else has already freed it don't redo their work */
2633                 spin_unlock(&cluster->lock);
2634                 return 0;
2635         }
2636         atomic_inc(&block_group->count);
2637         spin_unlock(&cluster->lock);
2638
2639         ctl = block_group->free_space_ctl;
2640
2641         /* now return any extents the cluster had on it */
2642         spin_lock(&ctl->tree_lock);
2643         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2644         spin_unlock(&ctl->tree_lock);
2645
2646         /* finally drop our ref */
2647         btrfs_put_block_group(block_group);
2648         return ret;
2649 }
2650
2651 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2652                                    struct btrfs_free_cluster *cluster,
2653                                    struct btrfs_free_space *entry,
2654                                    u64 bytes, u64 min_start,
2655                                    u64 *max_extent_size)
2656 {
2657         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2658         int err;
2659         u64 search_start = cluster->window_start;
2660         u64 search_bytes = bytes;
2661         u64 ret = 0;
2662
2663         search_start = min_start;
2664         search_bytes = bytes;
2665
2666         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2667         if (err) {
2668                 if (search_bytes > *max_extent_size)
2669                         *max_extent_size = search_bytes;
2670                 return 0;
2671         }
2672
2673         ret = search_start;
2674         __bitmap_clear_bits(ctl, entry, ret, bytes);
2675
2676         return ret;
2677 }
2678
2679 /*
2680  * given a cluster, try to allocate 'bytes' from it, returns 0
2681  * if it couldn't find anything suitably large, or a logical disk offset
2682  * if things worked out
2683  */
2684 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2685                              struct btrfs_free_cluster *cluster, u64 bytes,
2686                              u64 min_start, u64 *max_extent_size)
2687 {
2688         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2689         struct btrfs_free_space *entry = NULL;
2690         struct rb_node *node;
2691         u64 ret = 0;
2692
2693         spin_lock(&cluster->lock);
2694         if (bytes > cluster->max_size)
2695                 goto out;
2696
2697         if (cluster->block_group != block_group)
2698                 goto out;
2699
2700         node = rb_first(&cluster->root);
2701         if (!node)
2702                 goto out;
2703
2704         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2705         while (1) {
2706                 if (entry->bytes < bytes && entry->bytes > *max_extent_size)
2707                         *max_extent_size = entry->bytes;
2708
2709                 if (entry->bytes < bytes ||
2710                     (!entry->bitmap && entry->offset < min_start)) {
2711                         node = rb_next(&entry->offset_index);
2712                         if (!node)
2713                                 break;
2714                         entry = rb_entry(node, struct btrfs_free_space,
2715                                          offset_index);
2716                         continue;
2717                 }
2718
2719                 if (entry->bitmap) {
2720                         ret = btrfs_alloc_from_bitmap(block_group,
2721                                                       cluster, entry, bytes,
2722                                                       cluster->window_start,
2723                                                       max_extent_size);
2724                         if (ret == 0) {
2725                                 node = rb_next(&entry->offset_index);
2726                                 if (!node)
2727                                         break;
2728                                 entry = rb_entry(node, struct btrfs_free_space,
2729                                                  offset_index);
2730                                 continue;
2731                         }
2732                         cluster->window_start += bytes;
2733                 } else {
2734                         ret = entry->offset;
2735
2736                         entry->offset += bytes;
2737                         entry->bytes -= bytes;
2738                 }
2739
2740                 if (entry->bytes == 0)
2741                         rb_erase(&entry->offset_index, &cluster->root);
2742                 break;
2743         }
2744 out:
2745         spin_unlock(&cluster->lock);
2746
2747         if (!ret)
2748                 return 0;
2749
2750         spin_lock(&ctl->tree_lock);
2751
2752         ctl->free_space -= bytes;
2753         if (entry->bytes == 0) {
2754                 ctl->free_extents--;
2755                 if (entry->bitmap) {
2756                         kfree(entry->bitmap);
2757                         ctl->total_bitmaps--;
2758                         ctl->op->recalc_thresholds(ctl);
2759                 }
2760                 kmem_cache_free(btrfs_free_space_cachep, entry);
2761         }
2762
2763         spin_unlock(&ctl->tree_lock);
2764
2765         return ret;
2766 }
2767
2768 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2769                                 struct btrfs_free_space *entry,
2770                                 struct btrfs_free_cluster *cluster,
2771                                 u64 offset, u64 bytes,
2772                                 u64 cont1_bytes, u64 min_bytes)
2773 {
2774         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2775         unsigned long next_zero;
2776         unsigned long i;
2777         unsigned long want_bits;
2778         unsigned long min_bits;
2779         unsigned long found_bits;
2780         unsigned long start = 0;
2781         unsigned long total_found = 0;
2782         int ret;
2783
2784         i = offset_to_bit(entry->offset, ctl->unit,
2785                           max_t(u64, offset, entry->offset));
2786         want_bits = bytes_to_bits(bytes, ctl->unit);
2787         min_bits = bytes_to_bits(min_bytes, ctl->unit);
2788
2789 again:
2790         found_bits = 0;
2791         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2792                 next_zero = find_next_zero_bit(entry->bitmap,
2793                                                BITS_PER_BITMAP, i);
2794                 if (next_zero - i >= min_bits) {
2795                         found_bits = next_zero - i;
2796                         break;
2797                 }
2798                 i = next_zero;
2799         }
2800
2801         if (!found_bits)
2802                 return -ENOSPC;
2803
2804         if (!total_found) {
2805                 start = i;
2806                 cluster->max_size = 0;
2807         }
2808
2809         total_found += found_bits;
2810
2811         if (cluster->max_size < found_bits * ctl->unit)
2812                 cluster->max_size = found_bits * ctl->unit;
2813
2814         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2815                 i = next_zero + 1;
2816                 goto again;
2817         }
2818
2819         cluster->window_start = start * ctl->unit + entry->offset;
2820         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2821         ret = tree_insert_offset(&cluster->root, entry->offset,
2822                                  &entry->offset_index, 1);
2823         ASSERT(!ret); /* -EEXIST; Logic error */
2824
2825         trace_btrfs_setup_cluster(block_group, cluster,
2826                                   total_found * ctl->unit, 1);
2827         return 0;
2828 }
2829
2830 /*
2831  * This searches the block group for just extents to fill the cluster with.
2832  * Try to find a cluster with at least bytes total bytes, at least one
2833  * extent of cont1_bytes, and other clusters of at least min_bytes.
2834  */
2835 static noinline int
2836 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2837                         struct btrfs_free_cluster *cluster,
2838                         struct list_head *bitmaps, u64 offset, u64 bytes,
2839                         u64 cont1_bytes, u64 min_bytes)
2840 {
2841         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2842         struct btrfs_free_space *first = NULL;
2843         struct btrfs_free_space *entry = NULL;
2844         struct btrfs_free_space *last;
2845         struct rb_node *node;
2846         u64 window_free;
2847         u64 max_extent;
2848         u64 total_size = 0;
2849
2850         entry = tree_search_offset(ctl, offset, 0, 1);
2851         if (!entry)
2852                 return -ENOSPC;
2853
2854         /*
2855          * We don't want bitmaps, so just move along until we find a normal
2856          * extent entry.
2857          */
2858         while (entry->bitmap || entry->bytes < min_bytes) {
2859                 if (entry->bitmap && list_empty(&entry->list))
2860                         list_add_tail(&entry->list, bitmaps);
2861                 node = rb_next(&entry->offset_index);
2862                 if (!node)
2863                         return -ENOSPC;
2864                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2865         }
2866
2867         window_free = entry->bytes;
2868         max_extent = entry->bytes;
2869         first = entry;
2870         last = entry;
2871
2872         for (node = rb_next(&entry->offset_index); node;
2873              node = rb_next(&entry->offset_index)) {
2874                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2875
2876                 if (entry->bitmap) {
2877                         if (list_empty(&entry->list))
2878                                 list_add_tail(&entry->list, bitmaps);
2879                         continue;
2880                 }
2881
2882                 if (entry->bytes < min_bytes)
2883                         continue;
2884
2885                 last = entry;
2886                 window_free += entry->bytes;
2887                 if (entry->bytes > max_extent)
2888                         max_extent = entry->bytes;
2889         }
2890
2891         if (window_free < bytes || max_extent < cont1_bytes)
2892                 return -ENOSPC;
2893
2894         cluster->window_start = first->offset;
2895
2896         node = &first->offset_index;
2897
2898         /*
2899          * now we've found our entries, pull them out of the free space
2900          * cache and put them into the cluster rbtree
2901          */
2902         do {
2903                 int ret;
2904
2905                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2906                 node = rb_next(&entry->offset_index);
2907                 if (entry->bitmap || entry->bytes < min_bytes)
2908                         continue;
2909
2910                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2911                 ret = tree_insert_offset(&cluster->root, entry->offset,
2912                                          &entry->offset_index, 0);
2913                 total_size += entry->bytes;
2914                 ASSERT(!ret); /* -EEXIST; Logic error */
2915         } while (node && entry != last);
2916
2917         cluster->max_size = max_extent;
2918         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2919         return 0;
2920 }
2921
2922 /*
2923  * This specifically looks for bitmaps that may work in the cluster, we assume
2924  * that we have already failed to find extents that will work.
2925  */
2926 static noinline int
2927 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2928                      struct btrfs_free_cluster *cluster,
2929                      struct list_head *bitmaps, u64 offset, u64 bytes,
2930                      u64 cont1_bytes, u64 min_bytes)
2931 {
2932         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2933         struct btrfs_free_space *entry;
2934         int ret = -ENOSPC;
2935         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2936
2937         if (ctl->total_bitmaps == 0)
2938                 return -ENOSPC;
2939
2940         /*
2941          * The bitmap that covers offset won't be in the list unless offset
2942          * is just its start offset.
2943          */
2944         entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2945         if (entry->offset != bitmap_offset) {
2946                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2947                 if (entry && list_empty(&entry->list))
2948                         list_add(&entry->list, bitmaps);
2949         }
2950
2951         list_for_each_entry(entry, bitmaps, list) {
2952                 if (entry->bytes < bytes)
2953                         continue;
2954                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2955                                            bytes, cont1_bytes, min_bytes);
2956                 if (!ret)
2957                         return 0;
2958         }
2959
2960         /*
2961          * The bitmaps list has all the bitmaps that record free space
2962          * starting after offset, so no more search is required.
2963          */
2964         return -ENOSPC;
2965 }
2966
2967 /*
2968  * here we try to find a cluster of blocks in a block group.  The goal
2969  * is to find at least bytes+empty_size.
2970  * We might not find them all in one contiguous area.
2971  *
2972  * returns zero and sets up cluster if things worked out, otherwise
2973  * it returns -enospc
2974  */
2975 int btrfs_find_space_cluster(struct btrfs_root *root,
2976                              struct btrfs_block_group_cache *block_group,
2977                              struct btrfs_free_cluster *cluster,
2978                              u64 offset, u64 bytes, u64 empty_size)
2979 {
2980         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2981         struct btrfs_free_space *entry, *tmp;
2982         LIST_HEAD(bitmaps);
2983         u64 min_bytes;
2984         u64 cont1_bytes;
2985         int ret;
2986
2987         /*
2988          * Choose the minimum extent size we'll require for this
2989          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2990          * For metadata, allow allocates with smaller extents.  For
2991          * data, keep it dense.
2992          */
2993         if (btrfs_test_opt(root, SSD_SPREAD)) {
2994                 cont1_bytes = min_bytes = bytes + empty_size;
2995         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2996                 cont1_bytes = bytes;
2997                 min_bytes = block_group->sectorsize;
2998         } else {
2999                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3000                 min_bytes = block_group->sectorsize;
3001         }
3002
3003         spin_lock(&ctl->tree_lock);
3004
3005         /*
3006          * If we know we don't have enough space to make a cluster don't even
3007          * bother doing all the work to try and find one.
3008          */
3009         if (ctl->free_space < bytes) {
3010                 spin_unlock(&ctl->tree_lock);
3011                 return -ENOSPC;
3012         }
3013
3014         spin_lock(&cluster->lock);
3015
3016         /* someone already found a cluster, hooray */
3017         if (cluster->block_group) {
3018                 ret = 0;
3019                 goto out;
3020         }
3021
3022         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3023                                  min_bytes);
3024
3025         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3026                                       bytes + empty_size,
3027                                       cont1_bytes, min_bytes);
3028         if (ret)
3029                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3030                                            offset, bytes + empty_size,
3031                                            cont1_bytes, min_bytes);
3032
3033         /* Clear our temporary list */
3034         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3035                 list_del_init(&entry->list);
3036
3037         if (!ret) {
3038                 atomic_inc(&block_group->count);
3039                 list_add_tail(&cluster->block_group_list,
3040                               &block_group->cluster_list);
3041                 cluster->block_group = block_group;
3042         } else {
3043                 trace_btrfs_failed_cluster_setup(block_group);
3044         }
3045 out:
3046         spin_unlock(&cluster->lock);
3047         spin_unlock(&ctl->tree_lock);
3048
3049         return ret;
3050 }
3051
3052 /*
3053  * simple code to zero out a cluster
3054  */
3055 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3056 {
3057         spin_lock_init(&cluster->lock);
3058         spin_lock_init(&cluster->refill_lock);
3059         cluster->root = RB_ROOT;
3060         cluster->max_size = 0;
3061         INIT_LIST_HEAD(&cluster->block_group_list);
3062         cluster->block_group = NULL;
3063 }
3064
3065 static int do_trimming(struct btrfs_block_group_cache *block_group,
3066                        u64 *total_trimmed, u64 start, u64 bytes,
3067                        u64 reserved_start, u64 reserved_bytes,
3068                        struct btrfs_trim_range *trim_entry)
3069 {
3070         struct btrfs_space_info *space_info = block_group->space_info;
3071         struct btrfs_fs_info *fs_info = block_group->fs_info;
3072         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3073         int ret;
3074         int update = 0;
3075         u64 trimmed = 0;
3076
3077         spin_lock(&space_info->lock);
3078         spin_lock(&block_group->lock);
3079         if (!block_group->ro) {
3080                 block_group->reserved += reserved_bytes;
3081                 space_info->bytes_reserved += reserved_bytes;
3082                 update = 1;
3083         }
3084         spin_unlock(&block_group->lock);
3085         spin_unlock(&space_info->lock);
3086
3087         ret = btrfs_discard_extent(fs_info->extent_root,
3088                                    start, bytes, &trimmed);
3089         if (!ret)
3090                 *total_trimmed += trimmed;
3091
3092         mutex_lock(&ctl->cache_writeout_mutex);
3093         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
3094         list_del(&trim_entry->list);
3095         mutex_unlock(&ctl->cache_writeout_mutex);
3096
3097         if (update) {
3098                 spin_lock(&space_info->lock);
3099                 spin_lock(&block_group->lock);
3100                 if (block_group->ro)
3101                         space_info->bytes_readonly += reserved_bytes;
3102                 block_group->reserved -= reserved_bytes;
3103                 space_info->bytes_reserved -= reserved_bytes;
3104                 spin_unlock(&space_info->lock);
3105                 spin_unlock(&block_group->lock);
3106         }
3107
3108         return ret;
3109 }
3110
3111 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
3112                           u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3113 {
3114         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3115         struct btrfs_free_space *entry;
3116         struct rb_node *node;
3117         int ret = 0;
3118         u64 extent_start;
3119         u64 extent_bytes;
3120         u64 bytes;
3121
3122         while (start < end) {
3123                 struct btrfs_trim_range trim_entry;
3124
3125                 mutex_lock(&ctl->cache_writeout_mutex);
3126                 spin_lock(&ctl->tree_lock);
3127
3128                 if (ctl->free_space < minlen) {
3129                         spin_unlock(&ctl->tree_lock);
3130                         mutex_unlock(&ctl->cache_writeout_mutex);
3131                         break;
3132                 }
3133
3134                 entry = tree_search_offset(ctl, start, 0, 1);
3135                 if (!entry) {
3136                         spin_unlock(&ctl->tree_lock);
3137                         mutex_unlock(&ctl->cache_writeout_mutex);
3138                         break;
3139                 }
3140
3141                 /* skip bitmaps */
3142                 while (entry->bitmap) {
3143                         node = rb_next(&entry->offset_index);
3144                         if (!node) {
3145                                 spin_unlock(&ctl->tree_lock);
3146                                 mutex_unlock(&ctl->cache_writeout_mutex);
3147                                 goto out;
3148                         }
3149                         entry = rb_entry(node, struct btrfs_free_space,
3150                                          offset_index);
3151                 }
3152
3153                 if (entry->offset >= end) {
3154                         spin_unlock(&ctl->tree_lock);
3155                         mutex_unlock(&ctl->cache_writeout_mutex);
3156                         break;
3157                 }
3158
3159                 extent_start = entry->offset;
3160                 extent_bytes = entry->bytes;
3161                 start = max(start, extent_start);
3162                 bytes = min(extent_start + extent_bytes, end) - start;
3163                 if (bytes < minlen) {
3164                         spin_unlock(&ctl->tree_lock);
3165                         mutex_unlock(&ctl->cache_writeout_mutex);
3166                         goto next;
3167                 }
3168
3169                 unlink_free_space(ctl, entry);
3170                 kmem_cache_free(btrfs_free_space_cachep, entry);
3171
3172                 spin_unlock(&ctl->tree_lock);
3173                 trim_entry.start = extent_start;
3174                 trim_entry.bytes = extent_bytes;
3175                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3176                 mutex_unlock(&ctl->cache_writeout_mutex);
3177
3178                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3179                                   extent_start, extent_bytes, &trim_entry);
3180                 if (ret)
3181                         break;
3182 next:
3183                 start += bytes;
3184
3185                 if (fatal_signal_pending(current)) {
3186                         ret = -ERESTARTSYS;
3187                         break;
3188                 }
3189
3190                 cond_resched();
3191         }
3192 out:
3193         return ret;
3194 }
3195
3196 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
3197                         u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3198 {
3199         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3200         struct btrfs_free_space *entry;
3201         int ret = 0;
3202         int ret2;
3203         u64 bytes;
3204         u64 offset = offset_to_bitmap(ctl, start);
3205
3206         while (offset < end) {
3207                 bool next_bitmap = false;
3208                 struct btrfs_trim_range trim_entry;
3209
3210                 mutex_lock(&ctl->cache_writeout_mutex);
3211                 spin_lock(&ctl->tree_lock);
3212
3213                 if (ctl->free_space < minlen) {
3214                         spin_unlock(&ctl->tree_lock);
3215                         mutex_unlock(&ctl->cache_writeout_mutex);
3216                         break;
3217                 }
3218
3219                 entry = tree_search_offset(ctl, offset, 1, 0);
3220                 if (!entry) {
3221                         spin_unlock(&ctl->tree_lock);
3222                         mutex_unlock(&ctl->cache_writeout_mutex);
3223                         next_bitmap = true;
3224                         goto next;
3225                 }
3226
3227                 bytes = minlen;
3228                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
3229                 if (ret2 || start >= end) {
3230                         spin_unlock(&ctl->tree_lock);
3231                         mutex_unlock(&ctl->cache_writeout_mutex);
3232                         next_bitmap = true;
3233                         goto next;
3234                 }
3235
3236                 bytes = min(bytes, end - start);
3237                 if (bytes < minlen) {
3238                         spin_unlock(&ctl->tree_lock);
3239                         mutex_unlock(&ctl->cache_writeout_mutex);
3240                         goto next;
3241                 }
3242
3243                 bitmap_clear_bits(ctl, entry, start, bytes);
3244                 if (entry->bytes == 0)
3245                         free_bitmap(ctl, entry);
3246
3247                 spin_unlock(&ctl->tree_lock);
3248                 trim_entry.start = start;
3249                 trim_entry.bytes = bytes;
3250                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3251                 mutex_unlock(&ctl->cache_writeout_mutex);
3252
3253                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3254                                   start, bytes, &trim_entry);
3255                 if (ret)
3256                         break;
3257 next:
3258                 if (next_bitmap) {
3259                         offset += BITS_PER_BITMAP * ctl->unit;
3260                 } else {
3261                         start += bytes;
3262                         if (start >= offset + BITS_PER_BITMAP * ctl->unit)
3263                                 offset += BITS_PER_BITMAP * ctl->unit;
3264                 }
3265
3266                 if (fatal_signal_pending(current)) {
3267                         ret = -ERESTARTSYS;
3268                         break;
3269                 }
3270
3271                 cond_resched();
3272         }
3273
3274         return ret;
3275 }
3276
3277 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
3278                            u64 *trimmed, u64 start, u64 end, u64 minlen)
3279 {
3280         int ret;
3281
3282         *trimmed = 0;
3283
3284         spin_lock(&block_group->lock);
3285         if (block_group->removed) {
3286                 spin_unlock(&block_group->lock);
3287                 return 0;
3288         }
3289         atomic_inc(&block_group->trimming);
3290         spin_unlock(&block_group->lock);
3291
3292         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
3293         if (ret)
3294                 goto out;
3295
3296         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
3297 out:
3298         spin_lock(&block_group->lock);
3299         if (atomic_dec_and_test(&block_group->trimming) &&
3300             block_group->removed) {
3301                 struct extent_map_tree *em_tree;
3302                 struct extent_map *em;
3303
3304                 spin_unlock(&block_group->lock);
3305
3306                 lock_chunks(block_group->fs_info->chunk_root);
3307                 em_tree = &block_group->fs_info->mapping_tree.map_tree;
3308                 write_lock(&em_tree->lock);
3309                 em = lookup_extent_mapping(em_tree, block_group->key.objectid,
3310                                            1);
3311                 BUG_ON(!em); /* logic error, can't happen */
3312                 /*
3313                  * remove_extent_mapping() will delete us from the pinned_chunks
3314                  * list, which is protected by the chunk mutex.
3315                  */
3316                 remove_extent_mapping(em_tree, em);
3317                 write_unlock(&em_tree->lock);
3318                 unlock_chunks(block_group->fs_info->chunk_root);
3319
3320                 /* once for us and once for the tree */
3321                 free_extent_map(em);
3322                 free_extent_map(em);
3323
3324                 /*
3325                  * We've left one free space entry and other tasks trimming
3326                  * this block group have left 1 entry each one. Free them.
3327                  */
3328                 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3329         } else {
3330                 spin_unlock(&block_group->lock);
3331         }
3332
3333         return ret;
3334 }
3335
3336 /*
3337  * Find the left-most item in the cache tree, and then return the
3338  * smallest inode number in the item.
3339  *
3340  * Note: the returned inode number may not be the smallest one in
3341  * the tree, if the left-most item is a bitmap.
3342  */
3343 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
3344 {
3345         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
3346         struct btrfs_free_space *entry = NULL;
3347         u64 ino = 0;
3348
3349         spin_lock(&ctl->tree_lock);
3350
3351         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
3352                 goto out;
3353
3354         entry = rb_entry(rb_first(&ctl->free_space_offset),
3355                          struct btrfs_free_space, offset_index);
3356
3357         if (!entry->bitmap) {
3358                 ino = entry->offset;
3359
3360                 unlink_free_space(ctl, entry);
3361                 entry->offset++;
3362                 entry->bytes--;
3363                 if (!entry->bytes)
3364                         kmem_cache_free(btrfs_free_space_cachep, entry);
3365                 else
3366                         link_free_space(ctl, entry);
3367         } else {
3368                 u64 offset = 0;
3369                 u64 count = 1;
3370                 int ret;
3371
3372                 ret = search_bitmap(ctl, entry, &offset, &count);
3373                 /* Logic error; Should be empty if it can't find anything */
3374                 ASSERT(!ret);
3375
3376                 ino = offset;
3377                 bitmap_clear_bits(ctl, entry, offset, 1);
3378                 if (entry->bytes == 0)
3379                         free_bitmap(ctl, entry);
3380         }
3381 out:
3382         spin_unlock(&ctl->tree_lock);
3383
3384         return ino;
3385 }
3386
3387 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3388                                     struct btrfs_path *path)
3389 {
3390         struct inode *inode = NULL;
3391
3392         spin_lock(&root->ino_cache_lock);
3393         if (root->ino_cache_inode)
3394                 inode = igrab(root->ino_cache_inode);
3395         spin_unlock(&root->ino_cache_lock);
3396         if (inode)
3397                 return inode;
3398
3399         inode = __lookup_free_space_inode(root, path, 0);
3400         if (IS_ERR(inode))
3401                 return inode;
3402
3403         spin_lock(&root->ino_cache_lock);
3404         if (!btrfs_fs_closing(root->fs_info))
3405                 root->ino_cache_inode = igrab(inode);
3406         spin_unlock(&root->ino_cache_lock);
3407
3408         return inode;
3409 }
3410
3411 int create_free_ino_inode(struct btrfs_root *root,
3412                           struct btrfs_trans_handle *trans,
3413                           struct btrfs_path *path)
3414 {
3415         return __create_free_space_inode(root, trans, path,
3416                                          BTRFS_FREE_INO_OBJECTID, 0);
3417 }
3418
3419 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3420 {
3421         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3422         struct btrfs_path *path;
3423         struct inode *inode;
3424         int ret = 0;
3425         u64 root_gen = btrfs_root_generation(&root->root_item);
3426
3427         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3428                 return 0;
3429
3430         /*
3431          * If we're unmounting then just return, since this does a search on the
3432          * normal root and not the commit root and we could deadlock.
3433          */
3434         if (btrfs_fs_closing(fs_info))
3435                 return 0;
3436
3437         path = btrfs_alloc_path();
3438         if (!path)
3439                 return 0;
3440
3441         inode = lookup_free_ino_inode(root, path);
3442         if (IS_ERR(inode))
3443                 goto out;
3444
3445         if (root_gen != BTRFS_I(inode)->generation)
3446                 goto out_put;
3447
3448         ret = __load_free_space_cache(root, inode, ctl, path, 0);
3449
3450         if (ret < 0)
3451                 btrfs_err(fs_info,
3452                         "failed to load free ino cache for root %llu",
3453                         root->root_key.objectid);
3454 out_put:
3455         iput(inode);
3456 out:
3457         btrfs_free_path(path);
3458         return ret;
3459 }
3460
3461 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3462                               struct btrfs_trans_handle *trans,
3463                               struct btrfs_path *path,
3464                               struct inode *inode)
3465 {
3466         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3467         int ret;
3468         struct btrfs_io_ctl io_ctl;
3469
3470         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3471                 return 0;
3472
3473         memset(&io_ctl, 0, sizeof(io_ctl));
3474         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl,
3475                                       trans, path, 0);
3476         if (!ret)
3477                 ret = btrfs_wait_cache_io(root, trans, NULL, &io_ctl, path, 0);
3478
3479         if (ret) {
3480                 btrfs_delalloc_release_metadata(inode, inode->i_size);
3481 #ifdef DEBUG
3482                 btrfs_err(root->fs_info,
3483                         "failed to write free ino cache for root %llu",
3484                         root->root_key.objectid);
3485 #endif
3486         }
3487
3488         return ret;
3489 }
3490
3491 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3492 /*
3493  * Use this if you need to make a bitmap or extent entry specifically, it
3494  * doesn't do any of the merging that add_free_space does, this acts a lot like
3495  * how the free space cache loading stuff works, so you can get really weird
3496  * configurations.
3497  */
3498 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3499                               u64 offset, u64 bytes, bool bitmap)
3500 {
3501         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3502         struct btrfs_free_space *info = NULL, *bitmap_info;
3503         void *map = NULL;
3504         u64 bytes_added;
3505         int ret;
3506
3507 again:
3508         if (!info) {
3509                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3510                 if (!info)
3511                         return -ENOMEM;
3512         }
3513
3514         if (!bitmap) {
3515                 spin_lock(&ctl->tree_lock);
3516                 info->offset = offset;
3517                 info->bytes = bytes;
3518                 ret = link_free_space(ctl, info);
3519                 spin_unlock(&ctl->tree_lock);
3520                 if (ret)
3521                         kmem_cache_free(btrfs_free_space_cachep, info);
3522                 return ret;
3523         }
3524
3525         if (!map) {
3526                 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3527                 if (!map) {
3528                         kmem_cache_free(btrfs_free_space_cachep, info);
3529                         return -ENOMEM;
3530                 }
3531         }
3532
3533         spin_lock(&ctl->tree_lock);
3534         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3535                                          1, 0);
3536         if (!bitmap_info) {
3537                 info->bitmap = map;
3538                 map = NULL;
3539                 add_new_bitmap(ctl, info, offset);
3540                 bitmap_info = info;
3541                 info = NULL;
3542         }
3543
3544         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3545         bytes -= bytes_added;
3546         offset += bytes_added;
3547         spin_unlock(&ctl->tree_lock);
3548
3549         if (bytes)
3550                 goto again;
3551
3552         if (info)
3553                 kmem_cache_free(btrfs_free_space_cachep, info);
3554         if (map)
3555                 kfree(map);
3556         return 0;
3557 }
3558
3559 /*
3560  * Checks to see if the given range is in the free space cache.  This is really
3561  * just used to check the absence of space, so if there is free space in the
3562  * range at all we will return 1.
3563  */
3564 int test_check_exists(struct btrfs_block_group_cache *cache,
3565                       u64 offset, u64 bytes)
3566 {
3567         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3568         struct btrfs_free_space *info;
3569         int ret = 0;
3570
3571         spin_lock(&ctl->tree_lock);
3572         info = tree_search_offset(ctl, offset, 0, 0);
3573         if (!info) {
3574                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3575                                           1, 0);
3576                 if (!info)
3577                         goto out;
3578         }
3579
3580 have_info:
3581         if (info->bitmap) {
3582                 u64 bit_off, bit_bytes;
3583                 struct rb_node *n;
3584                 struct btrfs_free_space *tmp;
3585
3586                 bit_off = offset;
3587                 bit_bytes = ctl->unit;
3588                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3589                 if (!ret) {
3590                         if (bit_off == offset) {
3591                                 ret = 1;
3592                                 goto out;
3593                         } else if (bit_off > offset &&
3594                                    offset + bytes > bit_off) {
3595                                 ret = 1;
3596                                 goto out;
3597                         }
3598                 }
3599
3600                 n = rb_prev(&info->offset_index);
3601                 while (n) {
3602                         tmp = rb_entry(n, struct btrfs_free_space,
3603                                        offset_index);
3604                         if (tmp->offset + tmp->bytes < offset)
3605                                 break;
3606                         if (offset + bytes < tmp->offset) {
3607                                 n = rb_prev(&info->offset_index);
3608                                 continue;
3609                         }
3610                         info = tmp;
3611                         goto have_info;
3612                 }
3613
3614                 n = rb_next(&info->offset_index);
3615                 while (n) {
3616                         tmp = rb_entry(n, struct btrfs_free_space,
3617                                        offset_index);
3618                         if (offset + bytes < tmp->offset)
3619                                 break;
3620                         if (tmp->offset + tmp->bytes < offset) {
3621                                 n = rb_next(&info->offset_index);
3622                                 continue;
3623                         }
3624                         info = tmp;
3625                         goto have_info;
3626                 }
3627
3628                 ret = 0;
3629                 goto out;
3630         }
3631
3632         if (info->offset == offset) {
3633                 ret = 1;
3634                 goto out;
3635         }
3636
3637         if (offset > info->offset && offset < info->offset + info->bytes)
3638                 ret = 1;
3639 out:
3640         spin_unlock(&ctl->tree_lock);
3641         return ret;
3642 }
3643 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */