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
  31 #define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
  32 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
  33
  34 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  35                            struct btrfs_free_space *info);
  36 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  37                               struct btrfs_free_space *info);
  38
  39 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  40                                                struct btrfs_path *path,
  41                                                u64 offset)
  42 {
  43         struct btrfs_key key;
  44         struct btrfs_key location;
  45         struct btrfs_disk_key disk_key;
  46         struct btrfs_free_space_header *header;
  47         struct extent_buffer *leaf;
  48         struct inode *inode = NULL;
  49         int ret;
  50
  51         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  52         key.offset = offset;
  53         key.type = 0;
  54
  55         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  56         if (ret < 0)
  57                 return ERR_PTR(ret);
  58         if (ret > 0) {
  59                 btrfs_release_path(path);
  60                 return ERR_PTR(-ENOENT);
  61         }
  62
  63         leaf = path->nodes[0];
  64         header = btrfs_item_ptr(leaf, path->slots[0],
  65                                 struct btrfs_free_space_header);
  66         btrfs_free_space_key(leaf, header, &disk_key);
  67         btrfs_disk_key_to_cpu(&location, &disk_key);
  68         btrfs_release_path(path);
  69
  70         inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
  71         if (!inode)
  72                 return ERR_PTR(-ENOENT);
  73         if (IS_ERR(inode))
  74                 return inode;
  75         if (is_bad_inode(inode)) {
  76                 iput(inode);
  77                 return ERR_PTR(-ENOENT);
  78         }
  79
  80         mapping_set_gfp_mask(inode->i_mapping,
  81                         mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
  82
  83         return inode;
  84 }
  85
  86 struct inode *lookup_free_space_inode(struct btrfs_root *root,
  87                                       struct btrfs_block_group_cache
  88                                       *block_group, struct btrfs_path *path)
  89 {
  90         struct inode *inode = NULL;
  91         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
  92
  93         spin_lock(&block_group->lock);
  94         if (block_group->inode)
  95                 inode = igrab(block_group->inode);
  96         spin_unlock(&block_group->lock);
  97         if (inode)
  98                 return inode;
  99
 100         inode = __lookup_free_space_inode(root, path,
 101                                           block_group->key.objectid);
 102         if (IS_ERR(inode))
 103                 return inode;
 104
 105         spin_lock(&block_group->lock);
 106         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 107                 btrfs_info(root->fs_info,
 108                         "Old style space inode found, converting.");
 109                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 110                         BTRFS_INODE_NODATACOW;
 111                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 112         }
 113
 114         if (!block_group->iref) {
 115                 block_group->inode = igrab(inode);
 116                 block_group->iref = 1;
 117         }
 118         spin_unlock(&block_group->lock);
 119
 120         return inode;
 121 }
 122
 123 static int __create_free_space_inode(struct btrfs_root *root,
 124                                      struct btrfs_trans_handle *trans,
 125                                      struct btrfs_path *path,
 126                                      u64 ino, u64 offset)
 127 {
 128         struct btrfs_key key;
 129         struct btrfs_disk_key disk_key;
 130         struct btrfs_free_space_header *header;
 131         struct btrfs_inode_item *inode_item;
 132         struct extent_buffer *leaf;
 133         u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 134         int ret;
 135
 136         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 137         if (ret)
 138                 return ret;
 139
 140         /* We inline crc's for the free disk space cache */
 141         if (ino != BTRFS_FREE_INO_OBJECTID)
 142                 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 143
 144         leaf = path->nodes[0];
 145         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 146                                     struct btrfs_inode_item);
 147         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 148         memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
 149                              sizeof(*inode_item));
 150         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 151         btrfs_set_inode_size(leaf, inode_item, 0);
 152         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 153         btrfs_set_inode_uid(leaf, inode_item, 0);
 154         btrfs_set_inode_gid(leaf, inode_item, 0);
 155         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 156         btrfs_set_inode_flags(leaf, inode_item, flags);
 157         btrfs_set_inode_nlink(leaf, inode_item, 1);
 158         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 159         btrfs_set_inode_block_group(leaf, inode_item, offset);
 160         btrfs_mark_buffer_dirty(leaf);
 161         btrfs_release_path(path);
 162
 163         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 164         key.offset = offset;
 165         key.type = 0;
 166
 167         ret = btrfs_insert_empty_item(trans, root, path, &key,
 168                                       sizeof(struct btrfs_free_space_header));
 169         if (ret < 0) {
 170                 btrfs_release_path(path);
 171                 return ret;
 172         }
 173         leaf = path->nodes[0];
 174         header = btrfs_item_ptr(leaf, path->slots[0],
 175                                 struct btrfs_free_space_header);
 176         memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
 177         btrfs_set_free_space_key(leaf, header, &disk_key);
 178         btrfs_mark_buffer_dirty(leaf);
 179         btrfs_release_path(path);
 180
 181         return 0;
 182 }
 183
 184 int create_free_space_inode(struct btrfs_root *root,
 185                             struct btrfs_trans_handle *trans,
 186                             struct btrfs_block_group_cache *block_group,
 187                             struct btrfs_path *path)
 188 {
 189         int ret;
 190         u64 ino;
 191
 192         ret = btrfs_find_free_objectid(root, &ino);
 193         if (ret < 0)
 194                 return ret;
 195
 196         return __create_free_space_inode(root, trans, path, ino,
 197                                          block_group->key.objectid);
 198 }
 199
 200 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
 201                                     struct btrfs_trans_handle *trans,
 202                                     struct btrfs_path *path,
 203                                     struct inode *inode)
 204 {
 205         struct btrfs_block_rsv *rsv;
 206         u64 needed_bytes;
 207         loff_t oldsize;
 208         int ret = 0;
 209
 210         rsv = trans->block_rsv;
 211         trans->block_rsv = &root->fs_info->global_block_rsv;
 212
 213         /* 1 for slack space, 1 for updating the inode */
 214         needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
 215                 btrfs_calc_trans_metadata_size(root, 1);
 216
 217         spin_lock(&trans->block_rsv->lock);
 218         if (trans->block_rsv->reserved < needed_bytes) {
 219                 spin_unlock(&trans->block_rsv->lock);
 220                 trans->block_rsv = rsv;
 221                 return -ENOSPC;
 222         }
 223         spin_unlock(&trans->block_rsv->lock);
 224
 225         oldsize = i_size_read(inode);
 226         btrfs_i_size_write(inode, 0);
 227         truncate_pagecache(inode, oldsize, 0);
 228
 229         /*
 230          * We don't need an orphan item because truncating the free space cache
 231          * will never be split across transactions.
 232          */
 233         ret = btrfs_truncate_inode_items(trans, root, inode,
 234                                          0, BTRFS_EXTENT_DATA_KEY);
 235
 236         if (ret) {
 237                 trans->block_rsv = rsv;
 238                 btrfs_abort_transaction(trans, root, ret);
 239                 return ret;
 240         }
 241
 242         ret = btrfs_update_inode(trans, root, inode);
 243         if (ret)
 244                 btrfs_abort_transaction(trans, root, ret);
 245         trans->block_rsv = rsv;
 246
 247         return ret;
 248 }
 249
 250 static int readahead_cache(struct inode *inode)
 251 {
 252         struct file_ra_state *ra;
 253         unsigned long last_index;
 254
 255         ra = kzalloc(sizeof(*ra), GFP_NOFS);
 256         if (!ra)
 257                 return -ENOMEM;
 258
 259         file_ra_state_init(ra, inode->i_mapping);
 260         last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
 261
 262         page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 263
 264         kfree(ra);
 265
 266         return 0;
 267 }
 268
 269 struct io_ctl {
 270         void *cur, *orig;
 271         struct page *page;
 272         struct page **pages;
 273         struct btrfs_root *root;
 274         unsigned long size;
 275         int index;
 276         int num_pages;
 277         unsigned check_crcs:1;
 278 };
 279
 280 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
 281                        struct btrfs_root *root)
 282 {
 283         memset(io_ctl, 0, sizeof(struct io_ctl));
 284         io_ctl->num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
 285                 PAGE_CACHE_SHIFT;
 286         io_ctl->pages = kzalloc(sizeof(struct page *) * io_ctl->num_pages,
 287                                 GFP_NOFS);
 288         if (!io_ctl->pages)
 289                 return -ENOMEM;
 290         io_ctl->root = root;
 291         if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
 292                 io_ctl->check_crcs = 1;
 293         return 0;
 294 }
 295
 296 static void io_ctl_free(struct io_ctl *io_ctl)
 297 {
 298         kfree(io_ctl->pages);
 299 }
 300
 301 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
 302 {
 303         if (io_ctl->cur) {
 304                 kunmap(io_ctl->page);
 305                 io_ctl->cur = NULL;
 306                 io_ctl->orig = NULL;
 307         }
 308 }
 309
 310 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
 311 {
 312         BUG_ON(io_ctl->index >= io_ctl->num_pages);
 313         io_ctl->page = io_ctl->pages[io_ctl->index++];
 314         io_ctl->cur = kmap(io_ctl->page);
 315         io_ctl->orig = io_ctl->cur;
 316         io_ctl->size = PAGE_CACHE_SIZE;
 317         if (clear)
 318                 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
 319 }
 320
 321 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
 322 {
 323         int i;
 324
 325         io_ctl_unmap_page(io_ctl);
 326
 327         for (i = 0; i < io_ctl->num_pages; i++) {
 328                 if (io_ctl->pages[i]) {
 329                         ClearPageChecked(io_ctl->pages[i]);
 330                         unlock_page(io_ctl->pages[i]);
 331                         page_cache_release(io_ctl->pages[i]);
 332                 }
 333         }
 334 }
 335
 336 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
 337                                 int uptodate)
 338 {
 339         struct page *page;
 340         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 341         int i;
 342
 343         for (i = 0; i < io_ctl->num_pages; i++) {
 344                 page = find_or_create_page(inode->i_mapping, i, mask);
 345                 if (!page) {
 346                         io_ctl_drop_pages(io_ctl);
 347                         return -ENOMEM;
 348                 }
 349                 io_ctl->pages[i] = page;
 350                 if (uptodate && !PageUptodate(page)) {
 351                         btrfs_readpage(NULL, page);
 352                         lock_page(page);
 353                         if (!PageUptodate(page)) {
 354                                 printk(KERN_ERR "btrfs: error reading free "
 355                                        "space cache\n");
 356                                 io_ctl_drop_pages(io_ctl);
 357                                 return -EIO;
 358                         }
 359                 }
 360         }
 361
 362         for (i = 0; i < io_ctl->num_pages; i++) {
 363                 clear_page_dirty_for_io(io_ctl->pages[i]);
 364                 set_page_extent_mapped(io_ctl->pages[i]);
 365         }
 366
 367         return 0;
 368 }
 369
 370 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
 371 {
 372         __le64 *val;
 373
 374         io_ctl_map_page(io_ctl, 1);
 375
 376         /*
 377          * Skip the csum areas.  If we don't check crcs then we just have a
 378          * 64bit chunk at the front of the first page.
 379          */
 380         if (io_ctl->check_crcs) {
 381                 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 382                 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 383         } else {
 384                 io_ctl->cur += sizeof(u64);
 385                 io_ctl->size -= sizeof(u64) * 2;
 386         }
 387
 388         val = io_ctl->cur;
 389         *val = cpu_to_le64(generation);
 390         io_ctl->cur += sizeof(u64);
 391 }
 392
 393 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
 394 {
 395         __le64 *gen;
 396
 397         /*
 398          * Skip the crc area.  If we don't check crcs then we just have a 64bit
 399          * chunk at the front of the first page.
 400          */
 401         if (io_ctl->check_crcs) {
 402                 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 403                 io_ctl->size -= sizeof(u64) +
 404                         (sizeof(u32) * io_ctl->num_pages);
 405         } else {
 406                 io_ctl->cur += sizeof(u64);
 407                 io_ctl->size -= sizeof(u64) * 2;
 408         }
 409
 410         gen = io_ctl->cur;
 411         if (le64_to_cpu(*gen) != generation) {
 412                 printk_ratelimited(KERN_ERR "btrfs: space cache generation "
 413                                    "(%Lu) does not match inode (%Lu)\n", *gen,
 414                                    generation);
 415                 io_ctl_unmap_page(io_ctl);
 416                 return -EIO;
 417         }
 418         io_ctl->cur += sizeof(u64);
 419         return 0;
 420 }
 421
 422 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
 423 {
 424         u32 *tmp;
 425         u32 crc = ~(u32)0;
 426         unsigned offset = 0;
 427
 428         if (!io_ctl->check_crcs) {
 429                 io_ctl_unmap_page(io_ctl);
 430                 return;
 431         }
 432
 433         if (index == 0)
 434                 offset = sizeof(u32) * io_ctl->num_pages;
 435
 436         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 437                               PAGE_CACHE_SIZE - offset);
 438         btrfs_csum_final(crc, (char *)&crc);
 439         io_ctl_unmap_page(io_ctl);
 440         tmp = kmap(io_ctl->pages[0]);
 441         tmp += index;
 442         *tmp = crc;
 443         kunmap(io_ctl->pages[0]);
 444 }
 445
 446 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
 447 {
 448         u32 *tmp, val;
 449         u32 crc = ~(u32)0;
 450         unsigned offset = 0;
 451
 452         if (!io_ctl->check_crcs) {
 453                 io_ctl_map_page(io_ctl, 0);
 454                 return 0;
 455         }
 456
 457         if (index == 0)
 458                 offset = sizeof(u32) * io_ctl->num_pages;
 459
 460         tmp = kmap(io_ctl->pages[0]);
 461         tmp += index;
 462         val = *tmp;
 463         kunmap(io_ctl->pages[0]);
 464
 465         io_ctl_map_page(io_ctl, 0);
 466         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 467                               PAGE_CACHE_SIZE - offset);
 468         btrfs_csum_final(crc, (char *)&crc);
 469         if (val != crc) {
 470                 printk_ratelimited(KERN_ERR "btrfs: csum mismatch on free "
 471                                    "space cache\n");
 472                 io_ctl_unmap_page(io_ctl);
 473                 return -EIO;
 474         }
 475
 476         return 0;
 477 }
 478
 479 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
 480                             void *bitmap)
 481 {
 482         struct btrfs_free_space_entry *entry;
 483
 484         if (!io_ctl->cur)
 485                 return -ENOSPC;
 486
 487         entry = io_ctl->cur;
 488         entry->offset = cpu_to_le64(offset);
 489         entry->bytes = cpu_to_le64(bytes);
 490         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 491                 BTRFS_FREE_SPACE_EXTENT;
 492         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 493         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 494
 495         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 496                 return 0;
 497
 498         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 499
 500         /* No more pages to map */
 501         if (io_ctl->index >= io_ctl->num_pages)
 502                 return 0;
 503
 504         /* map the next page */
 505         io_ctl_map_page(io_ctl, 1);
 506         return 0;
 507 }
 508
 509 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
 510 {
 511         if (!io_ctl->cur)
 512                 return -ENOSPC;
 513
 514         /*
 515          * If we aren't at the start of the current page, unmap this one and
 516          * map the next one if there is any left.
 517          */
 518         if (io_ctl->cur != io_ctl->orig) {
 519                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 520                 if (io_ctl->index >= io_ctl->num_pages)
 521                         return -ENOSPC;
 522                 io_ctl_map_page(io_ctl, 0);
 523         }
 524
 525         memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
 526         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 527         if (io_ctl->index < io_ctl->num_pages)
 528                 io_ctl_map_page(io_ctl, 0);
 529         return 0;
 530 }
 531
 532 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
 533 {
 534         /*
 535          * If we're not on the boundary we know we've modified the page and we
 536          * need to crc the page.
 537          */
 538         if (io_ctl->cur != io_ctl->orig)
 539                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 540         else
 541                 io_ctl_unmap_page(io_ctl);
 542
 543         while (io_ctl->index < io_ctl->num_pages) {
 544                 io_ctl_map_page(io_ctl, 1);
 545                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 546         }
 547 }
 548
 549 static int io_ctl_read_entry(struct io_ctl *io_ctl,
 550                             struct btrfs_free_space *entry, u8 *type)
 551 {
 552         struct btrfs_free_space_entry *e;
 553         int ret;
 554
 555         if (!io_ctl->cur) {
 556                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 557                 if (ret)
 558                         return ret;
 559         }
 560
 561         e = io_ctl->cur;
 562         entry->offset = le64_to_cpu(e->offset);
 563         entry->bytes = le64_to_cpu(e->bytes);
 564         *type = e->type;
 565         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 566         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 567
 568         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 569                 return 0;
 570
 571         io_ctl_unmap_page(io_ctl);
 572
 573         return 0;
 574 }
 575
 576 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
 577                               struct btrfs_free_space *entry)
 578 {
 579         int ret;
 580
 581         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 582         if (ret)
 583                 return ret;
 584
 585         memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
 586         io_ctl_unmap_page(io_ctl);
 587
 588         return 0;
 589 }
 590
 591 /*
 592  * Since we attach pinned extents after the fact we can have contiguous sections
 593  * of free space that are split up in entries.  This poses a problem with the
 594  * tree logging stuff since it could have allocated across what appears to be 2
 595  * entries since we would have merged the entries when adding the pinned extents
 596  * back to the free space cache.  So run through the space cache that we just
 597  * loaded and merge contiguous entries.  This will make the log replay stuff not
 598  * blow up and it will make for nicer allocator behavior.
 599  */
 600 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
 601 {
 602         struct btrfs_free_space *e, *prev = NULL;
 603         struct rb_node *n;
 604
 605 again:
 606         spin_lock(&ctl->tree_lock);
 607         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 608                 e = rb_entry(n, struct btrfs_free_space, offset_index);
 609                 if (!prev)
 610                         goto next;
 611                 if (e->bitmap || prev->bitmap)
 612                         goto next;
 613                 if (prev->offset + prev->bytes == e->offset) {
 614                         unlink_free_space(ctl, prev);
 615                         unlink_free_space(ctl, e);
 616                         prev->bytes += e->bytes;
 617                         kmem_cache_free(btrfs_free_space_cachep, e);
 618                         link_free_space(ctl, prev);
 619                         prev = NULL;
 620                         spin_unlock(&ctl->tree_lock);
 621                         goto again;
 622                 }
 623 next:
 624                 prev = e;
 625         }
 626         spin_unlock(&ctl->tree_lock);
 627 }
 628
 629 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 630                                    struct btrfs_free_space_ctl *ctl,
 631                                    struct btrfs_path *path, u64 offset)
 632 {
 633         struct btrfs_free_space_header *header;
 634         struct extent_buffer *leaf;
 635         struct io_ctl io_ctl;
 636         struct btrfs_key key;
 637         struct btrfs_free_space *e, *n;
 638         struct list_head bitmaps;
 639         u64 num_entries;
 640         u64 num_bitmaps;
 641         u64 generation;
 642         u8 type;
 643         int ret = 0;
 644
 645         INIT_LIST_HEAD(&bitmaps);
 646
 647         /* Nothing in the space cache, goodbye */
 648         if (!i_size_read(inode))
 649                 return 0;
 650
 651         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 652         key.offset = offset;
 653         key.type = 0;
 654
 655         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 656         if (ret < 0)
 657                 return 0;
 658         else if (ret > 0) {
 659                 btrfs_release_path(path);
 660                 return 0;
 661         }
 662
 663         ret = -1;
 664
 665         leaf = path->nodes[0];
 666         header = btrfs_item_ptr(leaf, path->slots[0],
 667                                 struct btrfs_free_space_header);
 668         num_entries = btrfs_free_space_entries(leaf, header);
 669         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 670         generation = btrfs_free_space_generation(leaf, header);
 671         btrfs_release_path(path);
 672
 673         if (BTRFS_I(inode)->generation != generation) {
 674                 btrfs_err(root->fs_info,
 675                         "free space inode generation (%llu) "
 676                         "did not match free space cache generation (%llu)",
 677                         (unsigned long long)BTRFS_I(inode)->generation,
 678                         (unsigned long long)generation);
 679                 return 0;
 680         }
 681
 682         if (!num_entries)
 683                 return 0;
 684
 685         ret = io_ctl_init(&io_ctl, inode, root);
 686         if (ret)
 687                 return ret;
 688
 689         ret = readahead_cache(inode);
 690         if (ret)
 691                 goto out;
 692
 693         ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
 694         if (ret)
 695                 goto out;
 696
 697         ret = io_ctl_check_crc(&io_ctl, 0);
 698         if (ret)
 699                 goto free_cache;
 700
 701         ret = io_ctl_check_generation(&io_ctl, generation);
 702         if (ret)
 703                 goto free_cache;
 704
 705         while (num_entries) {
 706                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
 707                                       GFP_NOFS);
 708                 if (!e)
 709                         goto free_cache;
 710
 711                 ret = io_ctl_read_entry(&io_ctl, e, &type);
 712                 if (ret) {
 713                         kmem_cache_free(btrfs_free_space_cachep, e);
 714                         goto free_cache;
 715                 }
 716
 717                 if (!e->bytes) {
 718                         kmem_cache_free(btrfs_free_space_cachep, e);
 719                         goto free_cache;
 720                 }
 721
 722                 if (type == BTRFS_FREE_SPACE_EXTENT) {
 723                         spin_lock(&ctl->tree_lock);
 724                         ret = link_free_space(ctl, e);
 725                         spin_unlock(&ctl->tree_lock);
 726                         if (ret) {
 727                                 btrfs_err(root->fs_info,
 728                                         "Duplicate entries in free space cache, dumping");
 729                                 kmem_cache_free(btrfs_free_space_cachep, e);
 730                                 goto free_cache;
 731                         }
 732                 } else {
 733                         BUG_ON(!num_bitmaps);
 734                         num_bitmaps--;
 735                         e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 736                         if (!e->bitmap) {
 737                                 kmem_cache_free(
 738                                         btrfs_free_space_cachep, e);
 739                                 goto free_cache;
 740                         }
 741                         spin_lock(&ctl->tree_lock);
 742                         ret = link_free_space(ctl, e);
 743                         ctl->total_bitmaps++;
 744                         ctl->op->recalc_thresholds(ctl);
 745                         spin_unlock(&ctl->tree_lock);
 746                         if (ret) {
 747                                 btrfs_err(root->fs_info,
 748                                         "Duplicate entries in free space cache, dumping");
 749                                 kmem_cache_free(btrfs_free_space_cachep, e);
 750                                 goto free_cache;
 751                         }
 752                         list_add_tail(&e->list, &bitmaps);
 753                 }
 754
 755                 num_entries--;
 756         }
 757
 758         io_ctl_unmap_page(&io_ctl);
 759
 760         /*
 761          * We add the bitmaps at the end of the entries in order that
 762          * the bitmap entries are added to the cache.
 763          */
 764         list_for_each_entry_safe(e, n, &bitmaps, list) {
 765                 list_del_init(&e->list);
 766                 ret = io_ctl_read_bitmap(&io_ctl, e);
 767                 if (ret)
 768                         goto free_cache;
 769         }
 770
 771         io_ctl_drop_pages(&io_ctl);
 772         merge_space_tree(ctl);
 773         ret = 1;
 774 out:
 775         io_ctl_free(&io_ctl);
 776         return ret;
 777 free_cache:
 778         io_ctl_drop_pages(&io_ctl);
 779         __btrfs_remove_free_space_cache(ctl);
 780         goto out;
 781 }
 782
 783 int load_free_space_cache(struct btrfs_fs_info *fs_info,
 784                           struct btrfs_block_group_cache *block_group)
 785 {
 786         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 787         struct btrfs_root *root = fs_info->tree_root;
 788         struct inode *inode;
 789         struct btrfs_path *path;
 790         int ret = 0;
 791         bool matched;
 792         u64 used = btrfs_block_group_used(&block_group->item);
 793
 794         /*
 795          * If this block group has been marked to be cleared for one reason or
 796          * another then we can't trust the on disk cache, so just return.
 797          */
 798         spin_lock(&block_group->lock);
 799         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 800                 spin_unlock(&block_group->lock);
 801                 return 0;
 802         }
 803         spin_unlock(&block_group->lock);
 804
 805         path = btrfs_alloc_path();
 806         if (!path)
 807                 return 0;
 808         path->search_commit_root = 1;
 809         path->skip_locking = 1;
 810
 811         inode = lookup_free_space_inode(root, block_group, path);
 812         if (IS_ERR(inode)) {
 813                 btrfs_free_path(path);
 814                 return 0;
 815         }
 816
 817         /* We may have converted the inode and made the cache invalid. */
 818         spin_lock(&block_group->lock);
 819         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 820                 spin_unlock(&block_group->lock);
 821                 btrfs_free_path(path);
 822                 goto out;
 823         }
 824         spin_unlock(&block_group->lock);
 825
 826         ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 827                                       path, block_group->key.objectid);
 828         btrfs_free_path(path);
 829         if (ret <= 0)
 830                 goto out;
 831
 832         spin_lock(&ctl->tree_lock);
 833         matched = (ctl->free_space == (block_group->key.offset - used -
 834                                        block_group->bytes_super));
 835         spin_unlock(&ctl->tree_lock);
 836
 837         if (!matched) {
 838                 __btrfs_remove_free_space_cache(ctl);
 839                 btrfs_err(fs_info, "block group %llu has wrong amount of free space",
 840                         block_group->key.objectid);
 841                 ret = -1;
 842         }
 843 out:
 844         if (ret < 0) {
 845                 /* This cache is bogus, make sure it gets cleared */
 846                 spin_lock(&block_group->lock);
 847                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 848                 spin_unlock(&block_group->lock);
 849                 ret = 0;
 850
 851                 btrfs_err(fs_info, "failed to load free space cache for block group %llu",
 852                         block_group->key.objectid);
 853         }
 854
 855         iput(inode);
 856         return ret;
 857 }
 858
 859 /**
 860  * __btrfs_write_out_cache - write out cached info to an inode
 861  * @root - the root the inode belongs to
 862  * @ctl - the free space cache we are going to write out
 863  * @block_group - the block_group for this cache if it belongs to a block_group
 864  * @trans - the trans handle
 865  * @path - the path to use
 866  * @offset - the offset for the key we'll insert
 867  *
 868  * This function writes out a free space cache struct to disk for quick recovery
 869  * on mount.  This will return 0 if it was successfull in writing the cache out,
 870  * and -1 if it was not.
 871  */
 872 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 873                                    struct btrfs_free_space_ctl *ctl,
 874                                    struct btrfs_block_group_cache *block_group,
 875                                    struct btrfs_trans_handle *trans,
 876                                    struct btrfs_path *path, u64 offset)
 877 {
 878         struct btrfs_free_space_header *header;
 879         struct extent_buffer *leaf;
 880         struct rb_node *node;
 881         struct list_head *pos, *n;
 882         struct extent_state *cached_state = NULL;
 883         struct btrfs_free_cluster *cluster = NULL;
 884         struct extent_io_tree *unpin = NULL;
 885         struct io_ctl io_ctl;
 886         struct list_head bitmap_list;
 887         struct btrfs_key key;
 888         u64 start, extent_start, extent_end, len;
 889         int entries = 0;
 890         int bitmaps = 0;
 891         int ret;
 892         int err = -1;
 893
 894         INIT_LIST_HEAD(&bitmap_list);
 895
 896         if (!i_size_read(inode))
 897                 return -1;
 898
 899         ret = io_ctl_init(&io_ctl, inode, root);
 900         if (ret)
 901                 return -1;
 902
 903         /* Get the cluster for this block_group if it exists */
 904         if (block_group && !list_empty(&block_group->cluster_list))
 905                 cluster = list_entry(block_group->cluster_list.next,
 906                                      struct btrfs_free_cluster,
 907                                      block_group_list);
 908
 909         /* Lock all pages first so we can lock the extent safely. */
 910         io_ctl_prepare_pages(&io_ctl, inode, 0);
 911
 912         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
 913                          0, &cached_state);
 914
 915         node = rb_first(&ctl->free_space_offset);
 916         if (!node && cluster) {
 917                 node = rb_first(&cluster->root);
 918                 cluster = NULL;
 919         }
 920
 921         /* Make sure we can fit our crcs into the first page */
 922         if (io_ctl.check_crcs &&
 923             (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
 924                 goto out_nospc;
 925
 926         io_ctl_set_generation(&io_ctl, trans->transid);
 927
 928         /* Write out the extent entries */
 929         while (node) {
 930                 struct btrfs_free_space *e;
 931
 932                 e = rb_entry(node, struct btrfs_free_space, offset_index);
 933                 entries++;
 934
 935                 ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes,
 936                                        e->bitmap);
 937                 if (ret)
 938                         goto out_nospc;
 939
 940                 if (e->bitmap) {
 941                         list_add_tail(&e->list, &bitmap_list);
 942                         bitmaps++;
 943                 }
 944                 node = rb_next(node);
 945                 if (!node && cluster) {
 946                         node = rb_first(&cluster->root);
 947                         cluster = NULL;
 948                 }
 949         }
 950
 951         /*
 952          * We want to add any pinned extents to our free space cache
 953          * so we don't leak the space
 954          */
 955
 956         /*
 957          * We shouldn't have switched the pinned extents yet so this is the
 958          * right one
 959          */
 960         unpin = root->fs_info->pinned_extents;
 961
 962         if (block_group)
 963                 start = block_group->key.objectid;
 964
 965         while (block_group && (start < block_group->key.objectid +
 966                                block_group->key.offset)) {
 967                 ret = find_first_extent_bit(unpin, start,
 968                                             &extent_start, &extent_end,
 969                                             EXTENT_DIRTY, NULL);
 970                 if (ret) {
 971                         ret = 0;
 972                         break;
 973                 }
 974
 975                 /* This pinned extent is out of our range */
 976                 if (extent_start >= block_group->key.objectid +
 977                     block_group->key.offset)
 978                         break;
 979
 980                 extent_start = max(extent_start, start);
 981                 extent_end = min(block_group->key.objectid +
 982                                  block_group->key.offset, extent_end + 1);
 983                 len = extent_end - extent_start;
 984
 985                 entries++;
 986                 ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
 987                 if (ret)
 988                         goto out_nospc;
 989
 990                 start = extent_end;
 991         }
 992
 993         /* Write out the bitmaps */
 994         list_for_each_safe(pos, n, &bitmap_list) {
 995                 struct btrfs_free_space *entry =
 996                         list_entry(pos, struct btrfs_free_space, list);
 997
 998                 ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap);
 999                 if (ret)
1000                         goto out_nospc;
1001                 list_del_init(&entry->list);
1002         }
1003
1004         /* Zero out the rest of the pages just to make sure */
1005         io_ctl_zero_remaining_pages(&io_ctl);
1006
1007         ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1008                                 0, i_size_read(inode), &cached_state);
1009         io_ctl_drop_pages(&io_ctl);
1010         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1011                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1012
1013         if (ret)
1014                 goto out;
1015
1016
1017         btrfs_wait_ordered_range(inode, 0, (u64)-1);
1018
1019         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1020         key.offset = offset;
1021         key.type = 0;
1022
1023         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1024         if (ret < 0) {
1025                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1026                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1027                                  GFP_NOFS);
1028                 goto out;
1029         }
1030         leaf = path->nodes[0];
1031         if (ret > 0) {
1032                 struct btrfs_key found_key;
1033                 BUG_ON(!path->slots[0]);
1034                 path->slots[0]--;
1035                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1036                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1037                     found_key.offset != offset) {
1038                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1039                                          inode->i_size - 1,
1040                                          EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1041                                          NULL, GFP_NOFS);
1042                         btrfs_release_path(path);
1043                         goto out;
1044                 }
1045         }
1046
1047         BTRFS_I(inode)->generation = trans->transid;
1048         header = btrfs_item_ptr(leaf, path->slots[0],
1049                                 struct btrfs_free_space_header);
1050         btrfs_set_free_space_entries(leaf, header, entries);
1051         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1052         btrfs_set_free_space_generation(leaf, header, trans->transid);
1053         btrfs_mark_buffer_dirty(leaf);
1054         btrfs_release_path(path);
1055
1056         err = 0;
1057 out:
1058         io_ctl_free(&io_ctl);
1059         if (err) {
1060                 invalidate_inode_pages2(inode->i_mapping);
1061                 BTRFS_I(inode)->generation = 0;
1062         }
1063         btrfs_update_inode(trans, root, inode);
1064         return err;
1065
1066 out_nospc:
1067         list_for_each_safe(pos, n, &bitmap_list) {
1068                 struct btrfs_free_space *entry =
1069                         list_entry(pos, struct btrfs_free_space, list);
1070                 list_del_init(&entry->list);
1071         }
1072         io_ctl_drop_pages(&io_ctl);
1073         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1074                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1075         goto out;
1076 }
1077
1078 int btrfs_write_out_cache(struct btrfs_root *root,
1079                           struct btrfs_trans_handle *trans,
1080                           struct btrfs_block_group_cache *block_group,
1081                           struct btrfs_path *path)
1082 {
1083         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1084         struct inode *inode;
1085         int ret = 0;
1086
1087         root = root->fs_info->tree_root;
1088
1089         spin_lock(&block_group->lock);
1090         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1091                 spin_unlock(&block_group->lock);
1092                 return 0;
1093         }
1094         spin_unlock(&block_group->lock);
1095
1096         inode = lookup_free_space_inode(root, block_group, path);
1097         if (IS_ERR(inode))
1098                 return 0;
1099
1100         ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1101                                       path, block_group->key.objectid);
1102         if (ret) {
1103                 spin_lock(&block_group->lock);
1104                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1105                 spin_unlock(&block_group->lock);
1106                 ret = 0;
1107 #ifdef DEBUG
1108                 btrfs_err(root->fs_info,
1109                         "failed to write free space cache for block group %llu",
1110                         block_group->key.objectid);
1111 #endif
1112         }
1113
1114         iput(inode);
1115         return ret;
1116 }
1117
1118 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1119                                           u64 offset)
1120 {
1121         BUG_ON(offset < bitmap_start);
1122         offset -= bitmap_start;
1123         return (unsigned long)(div_u64(offset, unit));
1124 }
1125
1126 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1127 {
1128         return (unsigned long)(div_u64(bytes, unit));
1129 }
1130
1131 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1132                                    u64 offset)
1133 {
1134         u64 bitmap_start;
1135         u64 bytes_per_bitmap;
1136
1137         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1138         bitmap_start = offset - ctl->start;
1139         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1140         bitmap_start *= bytes_per_bitmap;
1141         bitmap_start += ctl->start;
1142
1143         return bitmap_start;
1144 }
1145
1146 static int tree_insert_offset(struct rb_root *root, u64 offset,
1147                               struct rb_node *node, int bitmap)
1148 {
1149         struct rb_node **p = &root->rb_node;
1150         struct rb_node *parent = NULL;
1151         struct btrfs_free_space *info;
1152
1153         while (*p) {
1154                 parent = *p;
1155                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1156
1157                 if (offset < info->offset) {
1158                         p = &(*p)->rb_left;
1159                 } else if (offset > info->offset) {
1160                         p = &(*p)->rb_right;
1161                 } else {
1162                         /*
1163                          * we could have a bitmap entry and an extent entry
1164                          * share the same offset.  If this is the case, we want
1165                          * the extent entry to always be found first if we do a
1166                          * linear search through the tree, since we want to have
1167                          * the quickest allocation time, and allocating from an
1168                          * extent is faster than allocating from a bitmap.  So
1169                          * if we're inserting a bitmap and we find an entry at
1170                          * this offset, we want to go right, or after this entry
1171                          * logically.  If we are inserting an extent and we've
1172                          * found a bitmap, we want to go left, or before
1173                          * logically.
1174                          */
1175                         if (bitmap) {
1176                                 if (info->bitmap) {
1177                                         WARN_ON_ONCE(1);
1178                                         return -EEXIST;
1179                                 }
1180                                 p = &(*p)->rb_right;
1181                         } else {
1182                                 if (!info->bitmap) {
1183                                         WARN_ON_ONCE(1);
1184                                         return -EEXIST;
1185                                 }
1186                                 p = &(*p)->rb_left;
1187                         }
1188                 }
1189         }
1190
1191         rb_link_node(node, parent, p);
1192         rb_insert_color(node, root);
1193
1194         return 0;
1195 }
1196
1197 /*
1198  * searches the tree for the given offset.
1199  *
1200  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1201  * want a section that has at least bytes size and comes at or after the given
1202  * offset.
1203  */
1204 static struct btrfs_free_space *
1205 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1206                    u64 offset, int bitmap_only, int fuzzy)
1207 {
1208         struct rb_node *n = ctl->free_space_offset.rb_node;
1209         struct btrfs_free_space *entry, *prev = NULL;
1210
1211         /* find entry that is closest to the 'offset' */
1212         while (1) {
1213                 if (!n) {
1214                         entry = NULL;
1215                         break;
1216                 }
1217
1218                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1219                 prev = entry;
1220
1221                 if (offset < entry->offset)
1222                         n = n->rb_left;
1223                 else if (offset > entry->offset)
1224                         n = n->rb_right;
1225                 else
1226                         break;
1227         }
1228
1229         if (bitmap_only) {
1230                 if (!entry)
1231                         return NULL;
1232                 if (entry->bitmap)
1233                         return entry;
1234
1235                 /*
1236                  * bitmap entry and extent entry may share same offset,
1237                  * in that case, bitmap entry comes after extent entry.
1238                  */
1239                 n = rb_next(n);
1240                 if (!n)
1241                         return NULL;
1242                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1243                 if (entry->offset != offset)
1244                         return NULL;
1245
1246                 WARN_ON(!entry->bitmap);
1247                 return entry;
1248         } else if (entry) {
1249                 if (entry->bitmap) {
1250                         /*
1251                          * if previous extent entry covers the offset,
1252                          * we should return it instead of the bitmap entry
1253                          */
1254                         n = rb_prev(&entry->offset_index);
1255                         if (n) {
1256                                 prev = rb_entry(n, struct btrfs_free_space,
1257                                                 offset_index);
1258                                 if (!prev->bitmap &&
1259                                     prev->offset + prev->bytes > offset)
1260                                         entry = prev;
1261                         }
1262                 }
1263                 return entry;
1264         }
1265
1266         if (!prev)
1267                 return NULL;
1268
1269         /* find last entry before the 'offset' */
1270         entry = prev;
1271         if (entry->offset > offset) {
1272                 n = rb_prev(&entry->offset_index);
1273                 if (n) {
1274                         entry = rb_entry(n, struct btrfs_free_space,
1275                                         offset_index);
1276                         BUG_ON(entry->offset > offset);
1277                 } else {
1278                         if (fuzzy)
1279                                 return entry;
1280                         else
1281                                 return NULL;
1282                 }
1283         }
1284
1285         if (entry->bitmap) {
1286                 n = rb_prev(&entry->offset_index);
1287                 if (n) {
1288                         prev = rb_entry(n, struct btrfs_free_space,
1289                                         offset_index);
1290                         if (!prev->bitmap &&
1291                             prev->offset + prev->bytes > offset)
1292                                 return prev;
1293                 }
1294                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1295                         return entry;
1296         } else if (entry->offset + entry->bytes > offset)
1297                 return entry;
1298
1299         if (!fuzzy)
1300                 return NULL;
1301
1302         while (1) {
1303                 if (entry->bitmap) {
1304                         if (entry->offset + BITS_PER_BITMAP *
1305                             ctl->unit > offset)
1306                                 break;
1307                 } else {
1308                         if (entry->offset + entry->bytes > offset)
1309                                 break;
1310                 }
1311
1312                 n = rb_next(&entry->offset_index);
1313                 if (!n)
1314                         return NULL;
1315                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1316         }
1317         return entry;
1318 }
1319
1320 static inline void
1321 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1322                     struct btrfs_free_space *info)
1323 {
1324         rb_erase(&info->offset_index, &ctl->free_space_offset);
1325         ctl->free_extents--;
1326 }
1327
1328 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1329                               struct btrfs_free_space *info)
1330 {
1331         __unlink_free_space(ctl, info);
1332         ctl->free_space -= info->bytes;
1333 }
1334
1335 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1336                            struct btrfs_free_space *info)
1337 {
1338         int ret = 0;
1339
1340         BUG_ON(!info->bitmap && !info->bytes);
1341         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1342                                  &info->offset_index, (info->bitmap != NULL));
1343         if (ret)
1344                 return ret;
1345
1346         ctl->free_space += info->bytes;
1347         ctl->free_extents++;
1348         return ret;
1349 }
1350
1351 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1352 {
1353         struct btrfs_block_group_cache *block_group = ctl->private;
1354         u64 max_bytes;
1355         u64 bitmap_bytes;
1356         u64 extent_bytes;
1357         u64 size = block_group->key.offset;
1358         u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1359         int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1360
1361         max_bitmaps = max(max_bitmaps, 1);
1362
1363         BUG_ON(ctl->total_bitmaps > max_bitmaps);
1364
1365         /*
1366          * The goal is to keep the total amount of memory used per 1gb of space
1367          * at or below 32k, so we need to adjust how much memory we allow to be
1368          * used by extent based free space tracking
1369          */
1370         if (size < 1024 * 1024 * 1024)
1371                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1372         else
1373                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1374                         div64_u64(size, 1024 * 1024 * 1024);
1375
1376         /*
1377          * we want to account for 1 more bitmap than what we have so we can make
1378          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1379          * we add more bitmaps.
1380          */
1381         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1382
1383         if (bitmap_bytes >= max_bytes) {
1384                 ctl->extents_thresh = 0;
1385                 return;
1386         }
1387
1388         /*
1389          * we want the extent entry threshold to always be at most 1/2 the maxw
1390          * bytes we can have, or whatever is less than that.
1391          */
1392         extent_bytes = max_bytes - bitmap_bytes;
1393         extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1394
1395         ctl->extents_thresh =
1396                 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1397 }
1398
1399 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1400                                        struct btrfs_free_space *info,
1401                                        u64 offset, u64 bytes)
1402 {
1403         unsigned long start, count;
1404
1405         start = offset_to_bit(info->offset, ctl->unit, offset);
1406         count = bytes_to_bits(bytes, ctl->unit);
1407         BUG_ON(start + count > BITS_PER_BITMAP);
1408
1409         bitmap_clear(info->bitmap, start, count);
1410
1411         info->bytes -= bytes;
1412 }
1413
1414 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1415                               struct btrfs_free_space *info, u64 offset,
1416                               u64 bytes)
1417 {
1418         __bitmap_clear_bits(ctl, info, offset, bytes);
1419         ctl->free_space -= bytes;
1420 }
1421
1422 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1423                             struct btrfs_free_space *info, u64 offset,
1424                             u64 bytes)
1425 {
1426         unsigned long start, count;
1427
1428         start = offset_to_bit(info->offset, ctl->unit, offset);
1429         count = bytes_to_bits(bytes, ctl->unit);
1430         BUG_ON(start + count > BITS_PER_BITMAP);
1431
1432         bitmap_set(info->bitmap, start, count);
1433
1434         info->bytes += bytes;
1435         ctl->free_space += bytes;
1436 }
1437
1438 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1439                          struct btrfs_free_space *bitmap_info, u64 *offset,
1440                          u64 *bytes)
1441 {
1442         unsigned long found_bits = 0;
1443         unsigned long bits, i;
1444         unsigned long next_zero;
1445
1446         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1447                           max_t(u64, *offset, bitmap_info->offset));
1448         bits = bytes_to_bits(*bytes, ctl->unit);
1449
1450         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1451                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1452                                                BITS_PER_BITMAP, i);
1453                 if ((next_zero - i) >= bits) {
1454                         found_bits = next_zero - i;
1455                         break;
1456                 }
1457                 i = next_zero;
1458         }
1459
1460         if (found_bits) {
1461                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1462                 *bytes = (u64)(found_bits) * ctl->unit;
1463                 return 0;
1464         }
1465
1466         return -1;
1467 }
1468
1469 static struct btrfs_free_space *
1470 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1471                 unsigned long align)
1472 {
1473         struct btrfs_free_space *entry;
1474         struct rb_node *node;
1475         u64 ctl_off;
1476         u64 tmp;
1477         u64 align_off;
1478         int ret;
1479
1480         if (!ctl->free_space_offset.rb_node)
1481                 return NULL;
1482
1483         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1484         if (!entry)
1485                 return NULL;
1486
1487         for (node = &entry->offset_index; node; node = rb_next(node)) {
1488                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1489                 if (entry->bytes < *bytes)
1490                         continue;
1491
1492                 /* make sure the space returned is big enough
1493                  * to match our requested alignment
1494                  */
1495                 if (*bytes >= align) {
1496                         ctl_off = entry->offset - ctl->start;
1497                         tmp = ctl_off + align - 1;;
1498                         do_div(tmp, align);
1499                         tmp = tmp * align + ctl->start;
1500                         align_off = tmp - entry->offset;
1501                 } else {
1502                         align_off = 0;
1503                         tmp = entry->offset;
1504                 }
1505
1506                 if (entry->bytes < *bytes + align_off)
1507                         continue;
1508
1509                 if (entry->bitmap) {
1510                         ret = search_bitmap(ctl, entry, &tmp, bytes);
1511                         if (!ret) {
1512                                 *offset = tmp;
1513                                 return entry;
1514                         }
1515                         continue;
1516                 }
1517
1518                 *offset = tmp;
1519                 *bytes = entry->bytes - align_off;
1520                 return entry;
1521         }
1522
1523         return NULL;
1524 }
1525
1526 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1527                            struct btrfs_free_space *info, u64 offset)
1528 {
1529         info->offset = offset_to_bitmap(ctl, offset);
1530         info->bytes = 0;
1531         INIT_LIST_HEAD(&info->list);
1532         link_free_space(ctl, info);
1533         ctl->total_bitmaps++;
1534
1535         ctl->op->recalc_thresholds(ctl);
1536 }
1537
1538 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1539                         struct btrfs_free_space *bitmap_info)
1540 {
1541         unlink_free_space(ctl, bitmap_info);
1542         kfree(bitmap_info->bitmap);
1543         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1544         ctl->total_bitmaps--;
1545         ctl->op->recalc_thresholds(ctl);
1546 }
1547
1548 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1549                               struct btrfs_free_space *bitmap_info,
1550                               u64 *offset, u64 *bytes)
1551 {
1552         u64 end;
1553         u64 search_start, search_bytes;
1554         int ret;
1555
1556 again:
1557         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1558
1559         /*
1560          * We need to search for bits in this bitmap.  We could only cover some
1561          * of the extent in this bitmap thanks to how we add space, so we need
1562          * to search for as much as it as we can and clear that amount, and then
1563          * go searching for the next bit.
1564          */
1565         search_start = *offset;
1566         search_bytes = ctl->unit;
1567         search_bytes = min(search_bytes, end - search_start + 1);
1568         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1569         if (ret < 0 || search_start != *offset)
1570                 return -EINVAL;
1571
1572         /* We may have found more bits than what we need */
1573         search_bytes = min(search_bytes, *bytes);
1574
1575         /* Cannot clear past the end of the bitmap */
1576         search_bytes = min(search_bytes, end - search_start + 1);
1577
1578         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1579         *offset += search_bytes;
1580         *bytes -= search_bytes;
1581
1582         if (*bytes) {
1583                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1584                 if (!bitmap_info->bytes)
1585                         free_bitmap(ctl, bitmap_info);
1586
1587                 /*
1588                  * no entry after this bitmap, but we still have bytes to
1589                  * remove, so something has gone wrong.
1590                  */
1591                 if (!next)
1592                         return -EINVAL;
1593
1594                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1595                                        offset_index);
1596
1597                 /*
1598                  * if the next entry isn't a bitmap we need to return to let the
1599                  * extent stuff do its work.
1600                  */
1601                 if (!bitmap_info->bitmap)
1602                         return -EAGAIN;
1603
1604                 /*
1605                  * Ok the next item is a bitmap, but it may not actually hold
1606                  * the information for the rest of this free space stuff, so
1607                  * look for it, and if we don't find it return so we can try
1608                  * everything over again.
1609                  */
1610                 search_start = *offset;
1611                 search_bytes = ctl->unit;
1612                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1613                                     &search_bytes);
1614                 if (ret < 0 || search_start != *offset)
1615                         return -EAGAIN;
1616
1617                 goto again;
1618         } else if (!bitmap_info->bytes)
1619                 free_bitmap(ctl, bitmap_info);
1620
1621         return 0;
1622 }
1623
1624 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1625                                struct btrfs_free_space *info, u64 offset,
1626                                u64 bytes)
1627 {
1628         u64 bytes_to_set = 0;
1629         u64 end;
1630
1631         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1632
1633         bytes_to_set = min(end - offset, bytes);
1634
1635         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1636
1637         return bytes_to_set;
1638
1639 }
1640
1641 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1642                       struct btrfs_free_space *info)
1643 {
1644         struct btrfs_block_group_cache *block_group = ctl->private;
1645
1646         /*
1647          * If we are below the extents threshold then we can add this as an
1648          * extent, and don't have to deal with the bitmap
1649          */
1650         if (ctl->free_extents < ctl->extents_thresh) {
1651                 /*
1652                  * If this block group has some small extents we don't want to
1653                  * use up all of our free slots in the cache with them, we want
1654                  * to reserve them to larger extents, however if we have plent
1655                  * of cache left then go ahead an dadd them, no sense in adding
1656                  * the overhead of a bitmap if we don't have to.
1657                  */
1658                 if (info->bytes <= block_group->sectorsize * 4) {
1659                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1660                                 return false;
1661                 } else {
1662                         return false;
1663                 }
1664         }
1665
1666         /*
1667          * The original block groups from mkfs can be really small, like 8
1668          * megabytes, so don't bother with a bitmap for those entries.  However
1669          * some block groups can be smaller than what a bitmap would cover but
1670          * are still large enough that they could overflow the 32k memory limit,
1671          * so allow those block groups to still be allowed to have a bitmap
1672          * entry.
1673          */
1674         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1675                 return false;
1676
1677         return true;
1678 }
1679
1680 static struct btrfs_free_space_op free_space_op = {
1681         .recalc_thresholds      = recalculate_thresholds,
1682         .use_bitmap             = use_bitmap,
1683 };
1684
1685 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1686                               struct btrfs_free_space *info)
1687 {
1688         struct btrfs_free_space *bitmap_info;
1689         struct btrfs_block_group_cache *block_group = NULL;
1690         int added = 0;
1691         u64 bytes, offset, bytes_added;
1692         int ret;
1693
1694         bytes = info->bytes;
1695         offset = info->offset;
1696
1697         if (!ctl->op->use_bitmap(ctl, info))
1698                 return 0;
1699
1700         if (ctl->op == &free_space_op)
1701                 block_group = ctl->private;
1702 again:
1703         /*
1704          * Since we link bitmaps right into the cluster we need to see if we
1705          * have a cluster here, and if so and it has our bitmap we need to add
1706          * the free space to that bitmap.
1707          */
1708         if (block_group && !list_empty(&block_group->cluster_list)) {
1709                 struct btrfs_free_cluster *cluster;
1710                 struct rb_node *node;
1711                 struct btrfs_free_space *entry;
1712
1713                 cluster = list_entry(block_group->cluster_list.next,
1714                                      struct btrfs_free_cluster,
1715                                      block_group_list);
1716                 spin_lock(&cluster->lock);
1717                 node = rb_first(&cluster->root);
1718                 if (!node) {
1719                         spin_unlock(&cluster->lock);
1720                         goto no_cluster_bitmap;
1721                 }
1722
1723                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1724                 if (!entry->bitmap) {
1725                         spin_unlock(&cluster->lock);
1726                         goto no_cluster_bitmap;
1727                 }
1728
1729                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1730                         bytes_added = add_bytes_to_bitmap(ctl, entry,
1731                                                           offset, bytes);
1732                         bytes -= bytes_added;
1733                         offset += bytes_added;
1734                 }
1735                 spin_unlock(&cluster->lock);
1736                 if (!bytes) {
1737                         ret = 1;
1738                         goto out;
1739                 }
1740         }
1741
1742 no_cluster_bitmap:
1743         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1744                                          1, 0);
1745         if (!bitmap_info) {
1746                 BUG_ON(added);
1747                 goto new_bitmap;
1748         }
1749
1750         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1751         bytes -= bytes_added;
1752         offset += bytes_added;
1753         added = 0;
1754
1755         if (!bytes) {
1756                 ret = 1;
1757                 goto out;
1758         } else
1759                 goto again;
1760
1761 new_bitmap:
1762         if (info && info->bitmap) {
1763                 add_new_bitmap(ctl, info, offset);
1764                 added = 1;
1765                 info = NULL;
1766                 goto again;
1767         } else {
1768                 spin_unlock(&ctl->tree_lock);
1769
1770                 /* no pre-allocated info, allocate a new one */
1771                 if (!info) {
1772                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
1773                                                  GFP_NOFS);
1774                         if (!info) {
1775                                 spin_lock(&ctl->tree_lock);
1776                                 ret = -ENOMEM;
1777                                 goto out;
1778                         }
1779                 }
1780
1781                 /* allocate the bitmap */
1782                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1783                 spin_lock(&ctl->tree_lock);
1784                 if (!info->bitmap) {
1785                         ret = -ENOMEM;
1786                         goto out;
1787                 }
1788                 goto again;
1789         }
1790
1791 out:
1792         if (info) {
1793                 if (info->bitmap)
1794                         kfree(info->bitmap);
1795                 kmem_cache_free(btrfs_free_space_cachep, info);
1796         }
1797
1798         return ret;
1799 }
1800
1801 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1802                           struct btrfs_free_space *info, bool update_stat)
1803 {
1804         struct btrfs_free_space *left_info;
1805         struct btrfs_free_space *right_info;
1806         bool merged = false;
1807         u64 offset = info->offset;
1808         u64 bytes = info->bytes;
1809
1810         /*
1811          * first we want to see if there is free space adjacent to the range we
1812          * are adding, if there is remove that struct and add a new one to
1813          * cover the entire range
1814          */
1815         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1816         if (right_info && rb_prev(&right_info->offset_index))
1817                 left_info = rb_entry(rb_prev(&right_info->offset_index),
1818                                      struct btrfs_free_space, offset_index);
1819         else
1820                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1821
1822         if (right_info && !right_info->bitmap) {
1823                 if (update_stat)
1824                         unlink_free_space(ctl, right_info);
1825                 else
1826                         __unlink_free_space(ctl, right_info);
1827                 info->bytes += right_info->bytes;
1828                 kmem_cache_free(btrfs_free_space_cachep, right_info);
1829                 merged = true;
1830         }
1831
1832         if (left_info && !left_info->bitmap &&
1833             left_info->offset + left_info->bytes == offset) {
1834                 if (update_stat)
1835                         unlink_free_space(ctl, left_info);
1836                 else
1837                         __unlink_free_space(ctl, left_info);
1838                 info->offset = left_info->offset;
1839                 info->bytes += left_info->bytes;
1840                 kmem_cache_free(btrfs_free_space_cachep, left_info);
1841                 merged = true;
1842         }
1843
1844         return merged;
1845 }
1846
1847 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1848                            u64 offset, u64 bytes)
1849 {
1850         struct btrfs_free_space *info;
1851         int ret = 0;
1852
1853         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1854         if (!info)
1855                 return -ENOMEM;
1856
1857         info->offset = offset;
1858         info->bytes = bytes;
1859
1860         spin_lock(&ctl->tree_lock);
1861
1862         if (try_merge_free_space(ctl, info, true))
1863                 goto link;
1864
1865         /*
1866          * There was no extent directly to the left or right of this new
1867          * extent then we know we're going to have to allocate a new extent, so
1868          * before we do that see if we need to drop this into a bitmap
1869          */
1870         ret = insert_into_bitmap(ctl, info);
1871         if (ret < 0) {
1872                 goto out;
1873         } else if (ret) {
1874                 ret = 0;
1875                 goto out;
1876         }
1877 link:
1878         ret = link_free_space(ctl, info);
1879         if (ret)
1880                 kmem_cache_free(btrfs_free_space_cachep, info);
1881 out:
1882         spin_unlock(&ctl->tree_lock);
1883
1884         if (ret) {
1885                 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1886                 BUG_ON(ret == -EEXIST);
1887         }
1888
1889         return ret;
1890 }
1891
1892 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1893                             u64 offset, u64 bytes)
1894 {
1895         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1896         struct btrfs_free_space *info;
1897         int ret;
1898         bool re_search = false;
1899
1900         spin_lock(&ctl->tree_lock);
1901
1902 again:
1903         ret = 0;
1904         if (!bytes)
1905                 goto out_lock;
1906
1907         info = tree_search_offset(ctl, offset, 0, 0);
1908         if (!info) {
1909                 /*
1910                  * oops didn't find an extent that matched the space we wanted
1911                  * to remove, look for a bitmap instead
1912                  */
1913                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1914                                           1, 0);
1915                 if (!info) {
1916                         /*
1917                          * If we found a partial bit of our free space in a
1918                          * bitmap but then couldn't find the other part this may
1919                          * be a problem, so WARN about it.
1920                          */
1921                         WARN_ON(re_search);
1922                         goto out_lock;
1923                 }
1924         }
1925
1926         re_search = false;
1927         if (!info->bitmap) {
1928                 unlink_free_space(ctl, info);
1929                 if (offset == info->offset) {
1930                         u64 to_free = min(bytes, info->bytes);
1931
1932                         info->bytes -= to_free;
1933                         info->offset += to_free;
1934                         if (info->bytes) {
1935                                 ret = link_free_space(ctl, info);
1936                                 WARN_ON(ret);
1937                         } else {
1938                                 kmem_cache_free(btrfs_free_space_cachep, info);
1939                         }
1940
1941                         offset += to_free;
1942                         bytes -= to_free;
1943                         goto again;
1944                 } else {
1945                         u64 old_end = info->bytes + info->offset;
1946
1947                         info->bytes = offset - info->offset;
1948                         ret = link_free_space(ctl, info);
1949                         WARN_ON(ret);
1950                         if (ret)
1951                                 goto out_lock;
1952
1953                         /* Not enough bytes in this entry to satisfy us */
1954                         if (old_end < offset + bytes) {
1955                                 bytes -= old_end - offset;
1956                                 offset = old_end;
1957                                 goto again;
1958                         } else if (old_end == offset + bytes) {
1959                                 /* all done */
1960                                 goto out_lock;
1961                         }
1962                         spin_unlock(&ctl->tree_lock);
1963
1964                         ret = btrfs_add_free_space(block_group, offset + bytes,
1965                                                    old_end - (offset + bytes));
1966                         WARN_ON(ret);
1967                         goto out;
1968                 }
1969         }
1970
1971         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1972         if (ret == -EAGAIN) {
1973                 re_search = true;
1974                 goto again;
1975         }
1976 out_lock:
1977         spin_unlock(&ctl->tree_lock);
1978 out:
1979         return ret;
1980 }
1981
1982 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1983                            u64 bytes)
1984 {
1985         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1986         struct btrfs_free_space *info;
1987         struct rb_node *n;
1988         int count = 0;
1989
1990         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1991                 info = rb_entry(n, struct btrfs_free_space, offset_index);
1992                 if (info->bytes >= bytes && !block_group->ro)
1993                         count++;
1994                 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1995                        (unsigned long long)info->offset,
1996                        (unsigned long long)info->bytes,
1997                        (info->bitmap) ? "yes" : "no");
1998         }
1999         printk(KERN_INFO "block group has cluster?: %s\n",
2000                list_empty(&block_group->cluster_list) ? "no" : "yes");
2001         printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
2002                "\n", count);
2003 }
2004
2005 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2006 {
2007         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2008
2009         spin_lock_init(&ctl->tree_lock);
2010         ctl->unit = block_group->sectorsize;
2011         ctl->start = block_group->key.objectid;
2012         ctl->private = block_group;
2013         ctl->op = &free_space_op;
2014
2015         /*
2016          * we only want to have 32k of ram per block group for keeping
2017          * track of free space, and if we pass 1/2 of that we want to
2018          * start converting things over to using bitmaps
2019          */
2020         ctl->extents_thresh = ((1024 * 32) / 2) /
2021                                 sizeof(struct btrfs_free_space);
2022 }
2023
2024 /*
2025  * for a given cluster, put all of its extents back into the free
2026  * space cache.  If the block group passed doesn't match the block group
2027  * pointed to by the cluster, someone else raced in and freed the
2028  * cluster already.  In that case, we just return without changing anything
2029  */
2030 static int
2031 __btrfs_return_cluster_to_free_space(
2032                              struct btrfs_block_group_cache *block_group,
2033                              struct btrfs_free_cluster *cluster)
2034 {
2035         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2036         struct btrfs_free_space *entry;
2037         struct rb_node *node;
2038
2039         spin_lock(&cluster->lock);
2040         if (cluster->block_group != block_group)
2041                 goto out;
2042
2043         cluster->block_group = NULL;
2044         cluster->window_start = 0;
2045         list_del_init(&cluster->block_group_list);
2046
2047         node = rb_first(&cluster->root);
2048         while (node) {
2049                 bool bitmap;
2050
2051                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2052                 node = rb_next(&entry->offset_index);
2053                 rb_erase(&entry->offset_index, &cluster->root);
2054
2055                 bitmap = (entry->bitmap != NULL);
2056                 if (!bitmap)
2057                         try_merge_free_space(ctl, entry, false);
2058                 tree_insert_offset(&ctl->free_space_offset,
2059                                    entry->offset, &entry->offset_index, bitmap);
2060         }
2061         cluster->root = RB_ROOT;
2062
2063 out:
2064         spin_unlock(&cluster->lock);
2065         btrfs_put_block_group(block_group);
2066         return 0;
2067 }
2068
2069 static void __btrfs_remove_free_space_cache_locked(
2070                                 struct btrfs_free_space_ctl *ctl)
2071 {
2072         struct btrfs_free_space *info;
2073         struct rb_node *node;
2074
2075         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2076                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2077                 if (!info->bitmap) {
2078                         unlink_free_space(ctl, info);
2079                         kmem_cache_free(btrfs_free_space_cachep, info);
2080                 } else {
2081                         free_bitmap(ctl, info);
2082                 }
2083                 if (need_resched()) {
2084                         spin_unlock(&ctl->tree_lock);
2085                         cond_resched();
2086                         spin_lock(&ctl->tree_lock);
2087                 }
2088         }
2089 }
2090
2091 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2092 {
2093         spin_lock(&ctl->tree_lock);
2094         __btrfs_remove_free_space_cache_locked(ctl);
2095         spin_unlock(&ctl->tree_lock);
2096 }
2097
2098 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2099 {
2100         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2101         struct btrfs_free_cluster *cluster;
2102         struct list_head *head;
2103
2104         spin_lock(&ctl->tree_lock);
2105         while ((head = block_group->cluster_list.next) !=
2106                &block_group->cluster_list) {
2107                 cluster = list_entry(head, struct btrfs_free_cluster,
2108                                      block_group_list);
2109
2110                 WARN_ON(cluster->block_group != block_group);
2111                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2112                 if (need_resched()) {
2113                         spin_unlock(&ctl->tree_lock);
2114                         cond_resched();
2115                         spin_lock(&ctl->tree_lock);
2116                 }
2117         }
2118         __btrfs_remove_free_space_cache_locked(ctl);
2119         spin_unlock(&ctl->tree_lock);
2120
2121 }
2122
2123 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2124                                u64 offset, u64 bytes, u64 empty_size)
2125 {
2126         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2127         struct btrfs_free_space *entry = NULL;
2128         u64 bytes_search = bytes + empty_size;
2129         u64 ret = 0;
2130         u64 align_gap = 0;
2131         u64 align_gap_len = 0;
2132
2133         spin_lock(&ctl->tree_lock);
2134         entry = find_free_space(ctl, &offset, &bytes_search,
2135                                 block_group->full_stripe_len);
2136         if (!entry)
2137                 goto out;
2138
2139         ret = offset;
2140         if (entry->bitmap) {
2141                 bitmap_clear_bits(ctl, entry, offset, bytes);
2142                 if (!entry->bytes)
2143                         free_bitmap(ctl, entry);
2144         } else {
2145
2146                 unlink_free_space(ctl, entry);
2147                 align_gap_len = offset - entry->offset;
2148                 align_gap = entry->offset;
2149
2150                 entry->offset = offset + bytes;
2151                 WARN_ON(entry->bytes < bytes + align_gap_len);
2152
2153                 entry->bytes -= bytes + align_gap_len;
2154                 if (!entry->bytes)
2155                         kmem_cache_free(btrfs_free_space_cachep, entry);
2156                 else
2157                         link_free_space(ctl, entry);
2158         }
2159
2160 out:
2161         spin_unlock(&ctl->tree_lock);
2162
2163         if (align_gap_len)
2164                 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2165         return ret;
2166 }
2167
2168 /*
2169  * given a cluster, put all of its extents back into the free space
2170  * cache.  If a block group is passed, this function will only free
2171  * a cluster that belongs to the passed block group.
2172  *
2173  * Otherwise, it'll get a reference on the block group pointed to by the
2174  * cluster and remove the cluster from it.
2175  */
2176 int btrfs_return_cluster_to_free_space(
2177                                struct btrfs_block_group_cache *block_group,
2178                                struct btrfs_free_cluster *cluster)
2179 {
2180         struct btrfs_free_space_ctl *ctl;
2181         int ret;
2182
2183         /* first, get a safe pointer to the block group */
2184         spin_lock(&cluster->lock);
2185         if (!block_group) {
2186                 block_group = cluster->block_group;
2187                 if (!block_group) {
2188                         spin_unlock(&cluster->lock);
2189                         return 0;
2190                 }
2191         } else if (cluster->block_group != block_group) {
2192                 /* someone else has already freed it don't redo their work */
2193                 spin_unlock(&cluster->lock);
2194                 return 0;
2195         }
2196         atomic_inc(&block_group->count);
2197         spin_unlock(&cluster->lock);
2198
2199         ctl = block_group->free_space_ctl;
2200
2201         /* now return any extents the cluster had on it */
2202         spin_lock(&ctl->tree_lock);
2203         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2204         spin_unlock(&ctl->tree_lock);
2205
2206         /* finally drop our ref */
2207         btrfs_put_block_group(block_group);
2208         return ret;
2209 }
2210
2211 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2212                                    struct btrfs_free_cluster *cluster,
2213                                    struct btrfs_free_space *entry,
2214                                    u64 bytes, u64 min_start)
2215 {
2216         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2217         int err;
2218         u64 search_start = cluster->window_start;
2219         u64 search_bytes = bytes;
2220         u64 ret = 0;
2221
2222         search_start = min_start;
2223         search_bytes = bytes;
2224
2225         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2226         if (err)
2227                 return 0;
2228
2229         ret = search_start;
2230         __bitmap_clear_bits(ctl, entry, ret, bytes);
2231
2232         return ret;
2233 }
2234
2235 /*
2236  * given a cluster, try to allocate 'bytes' from it, returns 0
2237  * if it couldn't find anything suitably large, or a logical disk offset
2238  * if things worked out
2239  */
2240 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2241                              struct btrfs_free_cluster *cluster, u64 bytes,
2242                              u64 min_start)
2243 {
2244         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2245         struct btrfs_free_space *entry = NULL;
2246         struct rb_node *node;
2247         u64 ret = 0;
2248
2249         spin_lock(&cluster->lock);
2250         if (bytes > cluster->max_size)
2251                 goto out;
2252
2253         if (cluster->block_group != block_group)
2254                 goto out;
2255
2256         node = rb_first(&cluster->root);
2257         if (!node)
2258                 goto out;
2259
2260         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2261         while(1) {
2262                 if (entry->bytes < bytes ||
2263                     (!entry->bitmap && entry->offset < min_start)) {
2264                         node = rb_next(&entry->offset_index);
2265                         if (!node)
2266                                 break;
2267                         entry = rb_entry(node, struct btrfs_free_space,
2268                                          offset_index);
2269                         continue;
2270                 }
2271
2272                 if (entry->bitmap) {
2273                         ret = btrfs_alloc_from_bitmap(block_group,
2274                                                       cluster, entry, bytes,
2275                                                       cluster->window_start);
2276                         if (ret == 0) {
2277                                 node = rb_next(&entry->offset_index);
2278                                 if (!node)
2279                                         break;
2280                                 entry = rb_entry(node, struct btrfs_free_space,
2281                                                  offset_index);
2282                                 continue;
2283                         }
2284                         cluster->window_start += bytes;
2285                 } else {
2286                         ret = entry->offset;
2287
2288                         entry->offset += bytes;
2289                         entry->bytes -= bytes;
2290                 }
2291
2292                 if (entry->bytes == 0)
2293                         rb_erase(&entry->offset_index, &cluster->root);
2294                 break;
2295         }
2296 out:
2297         spin_unlock(&cluster->lock);
2298
2299         if (!ret)
2300                 return 0;
2301
2302         spin_lock(&ctl->tree_lock);
2303
2304         ctl->free_space -= bytes;
2305         if (entry->bytes == 0) {
2306                 ctl->free_extents--;
2307                 if (entry->bitmap) {
2308                         kfree(entry->bitmap);
2309                         ctl->total_bitmaps--;
2310                         ctl->op->recalc_thresholds(ctl);
2311                 }
2312                 kmem_cache_free(btrfs_free_space_cachep, entry);
2313         }
2314
2315         spin_unlock(&ctl->tree_lock);
2316
2317         return ret;
2318 }
2319
2320 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2321                                 struct btrfs_free_space *entry,
2322                                 struct btrfs_free_cluster *cluster,
2323                                 u64 offset, u64 bytes,
2324                                 u64 cont1_bytes, u64 min_bytes)
2325 {
2326         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2327         unsigned long next_zero;
2328         unsigned long i;
2329         unsigned long want_bits;
2330         unsigned long min_bits;
2331         unsigned long found_bits;
2332         unsigned long start = 0;
2333         unsigned long total_found = 0;
2334         int ret;
2335
2336         i = offset_to_bit(entry->offset, ctl->unit,
2337                           max_t(u64, offset, entry->offset));
2338         want_bits = bytes_to_bits(bytes, ctl->unit);
2339         min_bits = bytes_to_bits(min_bytes, ctl->unit);
2340
2341 again:
2342         found_bits = 0;
2343         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2344                 next_zero = find_next_zero_bit(entry->bitmap,
2345                                                BITS_PER_BITMAP, i);
2346                 if (next_zero - i >= min_bits) {
2347                         found_bits = next_zero - i;
2348                         break;
2349                 }
2350                 i = next_zero;
2351         }
2352
2353         if (!found_bits)
2354                 return -ENOSPC;
2355
2356         if (!total_found) {
2357                 start = i;
2358                 cluster->max_size = 0;
2359         }
2360
2361         total_found += found_bits;
2362
2363         if (cluster->max_size < found_bits * ctl->unit)
2364                 cluster->max_size = found_bits * ctl->unit;
2365
2366         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2367                 i = next_zero + 1;
2368                 goto again;
2369         }
2370
2371         cluster->window_start = start * ctl->unit + entry->offset;
2372         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2373         ret = tree_insert_offset(&cluster->root, entry->offset,
2374                                  &entry->offset_index, 1);
2375         BUG_ON(ret); /* -EEXIST; Logic error */
2376
2377         trace_btrfs_setup_cluster(block_group, cluster,
2378                                   total_found * ctl->unit, 1);
2379         return 0;
2380 }
2381
2382 /*
2383  * This searches the block group for just extents to fill the cluster with.
2384  * Try to find a cluster with at least bytes total bytes, at least one
2385  * extent of cont1_bytes, and other clusters of at least min_bytes.
2386  */
2387 static noinline int
2388 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2389                         struct btrfs_free_cluster *cluster,
2390                         struct list_head *bitmaps, u64 offset, u64 bytes,
2391                         u64 cont1_bytes, u64 min_bytes)
2392 {
2393         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2394         struct btrfs_free_space *first = NULL;
2395         struct btrfs_free_space *entry = NULL;
2396         struct btrfs_free_space *last;
2397         struct rb_node *node;
2398         u64 window_start;
2399         u64 window_free;
2400         u64 max_extent;
2401         u64 total_size = 0;
2402
2403         entry = tree_search_offset(ctl, offset, 0, 1);
2404         if (!entry)
2405                 return -ENOSPC;
2406
2407         /*
2408          * We don't want bitmaps, so just move along until we find a normal
2409          * extent entry.
2410          */
2411         while (entry->bitmap || entry->bytes < min_bytes) {
2412                 if (entry->bitmap && list_empty(&entry->list))
2413                         list_add_tail(&entry->list, bitmaps);
2414                 node = rb_next(&entry->offset_index);
2415                 if (!node)
2416                         return -ENOSPC;
2417                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2418         }
2419
2420         window_start = entry->offset;
2421         window_free = entry->bytes;
2422         max_extent = entry->bytes;
2423         first = entry;
2424         last = entry;
2425
2426         for (node = rb_next(&entry->offset_index); node;
2427              node = rb_next(&entry->offset_index)) {
2428                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2429
2430                 if (entry->bitmap) {
2431                         if (list_empty(&entry->list))
2432                                 list_add_tail(&entry->list, bitmaps);
2433                         continue;
2434                 }
2435
2436                 if (entry->bytes < min_bytes)
2437                         continue;
2438
2439                 last = entry;
2440                 window_free += entry->bytes;
2441                 if (entry->bytes > max_extent)
2442                         max_extent = entry->bytes;
2443         }
2444
2445         if (window_free < bytes || max_extent < cont1_bytes)
2446                 return -ENOSPC;
2447
2448         cluster->window_start = first->offset;
2449
2450         node = &first->offset_index;
2451
2452         /*
2453          * now we've found our entries, pull them out of the free space
2454          * cache and put them into the cluster rbtree
2455          */
2456         do {
2457                 int ret;
2458
2459                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2460                 node = rb_next(&entry->offset_index);
2461                 if (entry->bitmap || entry->bytes < min_bytes)
2462                         continue;
2463
2464                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2465                 ret = tree_insert_offset(&cluster->root, entry->offset,
2466                                          &entry->offset_index, 0);
2467                 total_size += entry->bytes;
2468                 BUG_ON(ret); /* -EEXIST; Logic error */
2469         } while (node && entry != last);
2470
2471         cluster->max_size = max_extent;
2472         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2473         return 0;
2474 }
2475
2476 /*
2477  * This specifically looks for bitmaps that may work in the cluster, we assume
2478  * that we have already failed to find extents that will work.
2479  */
2480 static noinline int
2481 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2482                      struct btrfs_free_cluster *cluster,
2483                      struct list_head *bitmaps, u64 offset, u64 bytes,
2484                      u64 cont1_bytes, u64 min_bytes)
2485 {
2486         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2487         struct btrfs_free_space *entry;
2488         int ret = -ENOSPC;
2489         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2490
2491         if (ctl->total_bitmaps == 0)
2492                 return -ENOSPC;
2493
2494         /*
2495          * The bitmap that covers offset won't be in the list unless offset
2496          * is just its start offset.
2497          */
2498         entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2499         if (entry->offset != bitmap_offset) {
2500                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2501                 if (entry && list_empty(&entry->list))
2502                         list_add(&entry->list, bitmaps);
2503         }
2504
2505         list_for_each_entry(entry, bitmaps, list) {
2506                 if (entry->bytes < bytes)
2507                         continue;
2508                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2509                                            bytes, cont1_bytes, min_bytes);
2510                 if (!ret)
2511                         return 0;
2512         }
2513
2514         /*
2515          * The bitmaps list has all the bitmaps that record free space
2516          * starting after offset, so no more search is required.
2517          */
2518         return -ENOSPC;
2519 }
2520
2521 /*
2522  * here we try to find a cluster of blocks in a block group.  The goal
2523  * is to find at least bytes+empty_size.
2524  * We might not find them all in one contiguous area.
2525  *
2526  * returns zero and sets up cluster if things worked out, otherwise
2527  * it returns -enospc
2528  */
2529 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2530                              struct btrfs_root *root,
2531                              struct btrfs_block_group_cache *block_group,
2532                              struct btrfs_free_cluster *cluster,
2533                              u64 offset, u64 bytes, u64 empty_size)
2534 {
2535         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2536         struct btrfs_free_space *entry, *tmp;
2537         LIST_HEAD(bitmaps);
2538         u64 min_bytes;
2539         u64 cont1_bytes;
2540         int ret;
2541
2542         /*
2543          * Choose the minimum extent size we'll require for this
2544          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2545          * For metadata, allow allocates with smaller extents.  For
2546          * data, keep it dense.
2547          */
2548         if (btrfs_test_opt(root, SSD_SPREAD)) {
2549                 cont1_bytes = min_bytes = bytes + empty_size;
2550         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2551                 cont1_bytes = bytes;
2552                 min_bytes = block_group->sectorsize;
2553         } else {
2554                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2555                 min_bytes = block_group->sectorsize;
2556         }
2557
2558         spin_lock(&ctl->tree_lock);
2559
2560         /*
2561          * If we know we don't have enough space to make a cluster don't even
2562          * bother doing all the work to try and find one.
2563          */
2564         if (ctl->free_space < bytes) {
2565                 spin_unlock(&ctl->tree_lock);
2566                 return -ENOSPC;
2567         }
2568
2569         spin_lock(&cluster->lock);
2570
2571         /* someone already found a cluster, hooray */
2572         if (cluster->block_group) {
2573                 ret = 0;
2574                 goto out;
2575         }
2576
2577         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2578                                  min_bytes);
2579
2580         INIT_LIST_HEAD(&bitmaps);
2581         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2582                                       bytes + empty_size,
2583                                       cont1_bytes, min_bytes);
2584         if (ret)
2585                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2586                                            offset, bytes + empty_size,
2587                                            cont1_bytes, min_bytes);
2588
2589         /* Clear our temporary list */
2590         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2591                 list_del_init(&entry->list);
2592
2593         if (!ret) {
2594                 atomic_inc(&block_group->count);
2595                 list_add_tail(&cluster->block_group_list,
2596                               &block_group->cluster_list);
2597                 cluster->block_group = block_group;
2598         } else {
2599                 trace_btrfs_failed_cluster_setup(block_group);
2600         }
2601 out:
2602         spin_unlock(&cluster->lock);
2603         spin_unlock(&ctl->tree_lock);
2604
2605         return ret;
2606 }
2607
2608 /*
2609  * simple code to zero out a cluster
2610  */
2611 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2612 {
2613         spin_lock_init(&cluster->lock);
2614         spin_lock_init(&cluster->refill_lock);
2615         cluster->root = RB_ROOT;
2616         cluster->max_size = 0;
2617         INIT_LIST_HEAD(&cluster->block_group_list);
2618         cluster->block_group = NULL;
2619 }
2620
2621 static int do_trimming(struct btrfs_block_group_cache *block_group,
2622                        u64 *total_trimmed, u64 start, u64 bytes,
2623                        u64 reserved_start, u64 reserved_bytes)
2624 {
2625         struct btrfs_space_info *space_info = block_group->space_info;
2626         struct btrfs_fs_info *fs_info = block_group->fs_info;
2627         int ret;
2628         int update = 0;
2629         u64 trimmed = 0;
2630
2631         spin_lock(&space_info->lock);
2632         spin_lock(&block_group->lock);
2633         if (!block_group->ro) {
2634                 block_group->reserved += reserved_bytes;
2635                 space_info->bytes_reserved += reserved_bytes;
2636                 update = 1;
2637         }
2638         spin_unlock(&block_group->lock);
2639         spin_unlock(&space_info->lock);
2640
2641         ret = btrfs_error_discard_extent(fs_info->extent_root,
2642                                          start, bytes, &trimmed);
2643         if (!ret)
2644                 *total_trimmed += trimmed;
2645
2646         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2647
2648         if (update) {
2649                 spin_lock(&space_info->lock);
2650                 spin_lock(&block_group->lock);
2651                 if (block_group->ro)
2652                         space_info->bytes_readonly += reserved_bytes;
2653                 block_group->reserved -= reserved_bytes;
2654                 space_info->bytes_reserved -= reserved_bytes;
2655                 spin_unlock(&space_info->lock);
2656                 spin_unlock(&block_group->lock);
2657         }
2658
2659         return ret;
2660 }
2661
2662 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2663                           u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2664 {
2665         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2666         struct btrfs_free_space *entry;
2667         struct rb_node *node;
2668         int ret = 0;
2669         u64 extent_start;
2670         u64 extent_bytes;
2671         u64 bytes;
2672
2673         while (start < end) {
2674                 spin_lock(&ctl->tree_lock);
2675
2676                 if (ctl->free_space < minlen) {
2677                         spin_unlock(&ctl->tree_lock);
2678                         break;
2679                 }
2680
2681                 entry = tree_search_offset(ctl, start, 0, 1);
2682                 if (!entry) {
2683                         spin_unlock(&ctl->tree_lock);
2684                         break;
2685                 }
2686
2687                 /* skip bitmaps */
2688                 while (entry->bitmap) {
2689                         node = rb_next(&entry->offset_index);
2690                         if (!node) {
2691                                 spin_unlock(&ctl->tree_lock);
2692                                 goto out;
2693                         }
2694                         entry = rb_entry(node, struct btrfs_free_space,
2695                                          offset_index);
2696                 }
2697
2698                 if (entry->offset >= end) {
2699                         spin_unlock(&ctl->tree_lock);
2700                         break;
2701                 }
2702
2703                 extent_start = entry->offset;
2704                 extent_bytes = entry->bytes;
2705                 start = max(start, extent_start);
2706                 bytes = min(extent_start + extent_bytes, end) - start;
2707                 if (bytes < minlen) {
2708                         spin_unlock(&ctl->tree_lock);
2709                         goto next;
2710                 }
2711
2712                 unlink_free_space(ctl, entry);
2713                 kmem_cache_free(btrfs_free_space_cachep, entry);
2714
2715                 spin_unlock(&ctl->tree_lock);
2716
2717                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2718                                   extent_start, extent_bytes);
2719                 if (ret)
2720                         break;
2721 next:
2722                 start += bytes;
2723
2724                 if (fatal_signal_pending(current)) {
2725                         ret = -ERESTARTSYS;
2726                         break;
2727                 }
2728
2729                 cond_resched();
2730         }
2731 out:
2732         return ret;
2733 }
2734
2735 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2736                         u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2737 {
2738         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2739         struct btrfs_free_space *entry;
2740         int ret = 0;
2741         int ret2;
2742         u64 bytes;
2743         u64 offset = offset_to_bitmap(ctl, start);
2744
2745         while (offset < end) {
2746                 bool next_bitmap = false;
2747
2748                 spin_lock(&ctl->tree_lock);
2749
2750                 if (ctl->free_space < minlen) {
2751                         spin_unlock(&ctl->tree_lock);
2752                         break;
2753                 }
2754
2755                 entry = tree_search_offset(ctl, offset, 1, 0);
2756                 if (!entry) {
2757                         spin_unlock(&ctl->tree_lock);
2758                         next_bitmap = true;
2759                         goto next;
2760                 }
2761
2762                 bytes = minlen;
2763                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2764                 if (ret2 || start >= end) {
2765                         spin_unlock(&ctl->tree_lock);
2766                         next_bitmap = true;
2767                         goto next;
2768                 }
2769
2770                 bytes = min(bytes, end - start);
2771                 if (bytes < minlen) {
2772                         spin_unlock(&ctl->tree_lock);
2773                         goto next;
2774                 }
2775
2776                 bitmap_clear_bits(ctl, entry, start, bytes);
2777                 if (entry->bytes == 0)
2778                         free_bitmap(ctl, entry);
2779
2780                 spin_unlock(&ctl->tree_lock);
2781
2782                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2783                                   start, bytes);
2784                 if (ret)
2785                         break;
2786 next:
2787                 if (next_bitmap) {
2788                         offset += BITS_PER_BITMAP * ctl->unit;
2789                 } else {
2790                         start += bytes;
2791                         if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2792                                 offset += BITS_PER_BITMAP * ctl->unit;
2793                 }
2794
2795                 if (fatal_signal_pending(current)) {
2796                         ret = -ERESTARTSYS;
2797                         break;
2798                 }
2799
2800                 cond_resched();
2801         }
2802
2803         return ret;
2804 }
2805
2806 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2807                            u64 *trimmed, u64 start, u64 end, u64 minlen)
2808 {
2809         int ret;
2810
2811         *trimmed = 0;
2812
2813         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2814         if (ret)
2815                 return ret;
2816
2817         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2818
2819         return ret;
2820 }
2821
2822 /*
2823  * Find the left-most item in the cache tree, and then return the
2824  * smallest inode number in the item.
2825  *
2826  * Note: the returned inode number may not be the smallest one in
2827  * the tree, if the left-most item is a bitmap.
2828  */
2829 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2830 {
2831         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2832         struct btrfs_free_space *entry = NULL;
2833         u64 ino = 0;
2834
2835         spin_lock(&ctl->tree_lock);
2836
2837         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2838                 goto out;
2839
2840         entry = rb_entry(rb_first(&ctl->free_space_offset),
2841                          struct btrfs_free_space, offset_index);
2842
2843         if (!entry->bitmap) {
2844                 ino = entry->offset;
2845
2846                 unlink_free_space(ctl, entry);
2847                 entry->offset++;
2848                 entry->bytes--;
2849                 if (!entry->bytes)
2850                         kmem_cache_free(btrfs_free_space_cachep, entry);
2851                 else
2852                         link_free_space(ctl, entry);
2853         } else {
2854                 u64 offset = 0;
2855                 u64 count = 1;
2856                 int ret;
2857
2858                 ret = search_bitmap(ctl, entry, &offset, &count);
2859                 /* Logic error; Should be empty if it can't find anything */
2860                 BUG_ON(ret);
2861
2862                 ino = offset;
2863                 bitmap_clear_bits(ctl, entry, offset, 1);
2864                 if (entry->bytes == 0)
2865                         free_bitmap(ctl, entry);
2866         }
2867 out:
2868         spin_unlock(&ctl->tree_lock);
2869
2870         return ino;
2871 }
2872
2873 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2874                                     struct btrfs_path *path)
2875 {
2876         struct inode *inode = NULL;
2877
2878         spin_lock(&root->cache_lock);
2879         if (root->cache_inode)
2880                 inode = igrab(root->cache_inode);
2881         spin_unlock(&root->cache_lock);
2882         if (inode)
2883                 return inode;
2884
2885         inode = __lookup_free_space_inode(root, path, 0);
2886         if (IS_ERR(inode))
2887                 return inode;
2888
2889         spin_lock(&root->cache_lock);
2890         if (!btrfs_fs_closing(root->fs_info))
2891                 root->cache_inode = igrab(inode);
2892         spin_unlock(&root->cache_lock);
2893
2894         return inode;
2895 }
2896
2897 int create_free_ino_inode(struct btrfs_root *root,
2898                           struct btrfs_trans_handle *trans,
2899                           struct btrfs_path *path)
2900 {
2901         return __create_free_space_inode(root, trans, path,
2902                                          BTRFS_FREE_INO_OBJECTID, 0);
2903 }
2904
2905 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2906 {
2907         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2908         struct btrfs_path *path;
2909         struct inode *inode;
2910         int ret = 0;
2911         u64 root_gen = btrfs_root_generation(&root->root_item);
2912
2913         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2914                 return 0;
2915
2916         /*
2917          * If we're unmounting then just return, since this does a search on the
2918          * normal root and not the commit root and we could deadlock.
2919          */
2920         if (btrfs_fs_closing(fs_info))
2921                 return 0;
2922
2923         path = btrfs_alloc_path();
2924         if (!path)
2925                 return 0;
2926
2927         inode = lookup_free_ino_inode(root, path);
2928         if (IS_ERR(inode))
2929                 goto out;
2930
2931         if (root_gen != BTRFS_I(inode)->generation)
2932                 goto out_put;
2933
2934         ret = __load_free_space_cache(root, inode, ctl, path, 0);
2935
2936         if (ret < 0)
2937                 btrfs_err(fs_info,
2938                         "failed to load free ino cache for root %llu",
2939                         root->root_key.objectid);
2940 out_put:
2941         iput(inode);
2942 out:
2943         btrfs_free_path(path);
2944         return ret;
2945 }
2946
2947 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2948                               struct btrfs_trans_handle *trans,
2949                               struct btrfs_path *path)
2950 {
2951         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2952         struct inode *inode;
2953         int ret;
2954
2955         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2956                 return 0;
2957
2958         inode = lookup_free_ino_inode(root, path);
2959         if (IS_ERR(inode))
2960                 return 0;
2961
2962         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2963         if (ret) {
2964                 btrfs_delalloc_release_metadata(inode, inode->i_size);
2965 #ifdef DEBUG
2966                 btrfs_err(root->fs_info,
2967                         "failed to write free ino cache for root %llu",
2968                         root->root_key.objectid);
2969 #endif
2970         }
2971
2972         iput(inode);
2973         return ret;
2974 }
2975
2976 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
2977 static struct btrfs_block_group_cache *init_test_block_group(void)
2978 {
2979         struct btrfs_block_group_cache *cache;
2980
2981         cache = kzalloc(sizeof(*cache), GFP_NOFS);
2982         if (!cache)
2983                 return NULL;
2984         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
2985                                         GFP_NOFS);
2986         if (!cache->free_space_ctl) {
2987                 kfree(cache);
2988                 return NULL;
2989         }
2990
2991         cache->key.objectid = 0;
2992         cache->key.offset = 1024 * 1024 * 1024;
2993         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2994         cache->sectorsize = 4096;
2995
2996         spin_lock_init(&cache->lock);
2997         INIT_LIST_HEAD(&cache->list);
2998         INIT_LIST_HEAD(&cache->cluster_list);
2999         INIT_LIST_HEAD(&cache->new_bg_list);
3000
3001         btrfs_init_free_space_ctl(cache);
3002
3003         return cache;
3004 }
3005
3006 /*
3007  * Checks to see if the given range is in the free space cache.  This is really
3008  * just used to check the absence of space, so if there is free space in the
3009  * range at all we will return 1.
3010  */
3011 static int check_exists(struct btrfs_block_group_cache *cache, u64 offset,
3012                         u64 bytes)
3013 {
3014         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3015         struct btrfs_free_space *info;
3016         int ret = 0;
3017
3018         spin_lock(&ctl->tree_lock);
3019         info = tree_search_offset(ctl, offset, 0, 0);
3020         if (!info) {
3021                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3022                                           1, 0);
3023                 if (!info)
3024                         goto out;
3025         }
3026
3027 have_info:
3028         if (info->bitmap) {
3029                 u64 bit_off, bit_bytes;
3030                 struct rb_node *n;
3031                 struct btrfs_free_space *tmp;
3032
3033                 bit_off = offset;
3034                 bit_bytes = ctl->unit;
3035                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3036                 if (!ret) {
3037                         if (bit_off == offset) {
3038                                 ret = 1;
3039                                 goto out;
3040                         } else if (bit_off > offset &&
3041                                    offset + bytes > bit_off) {
3042                                 ret = 1;
3043                                 goto out;
3044                         }
3045                 }
3046
3047                 n = rb_prev(&info->offset_index);
3048                 while (n) {
3049                         tmp = rb_entry(n, struct btrfs_free_space,
3050                                        offset_index);
3051                         if (tmp->offset + tmp->bytes < offset)
3052                                 break;
3053                         if (offset + bytes < tmp->offset) {
3054                                 n = rb_prev(&info->offset_index);
3055                                 continue;
3056                         }
3057                         info = tmp;
3058                         goto have_info;
3059                 }
3060
3061                 n = rb_next(&info->offset_index);
3062                 while (n) {
3063                         tmp = rb_entry(n, struct btrfs_free_space,
3064                                        offset_index);
3065                         if (offset + bytes < tmp->offset)
3066                                 break;
3067                         if (tmp->offset + tmp->bytes < offset) {
3068                                 n = rb_next(&info->offset_index);
3069                                 continue;
3070                         }
3071                         info = tmp;
3072                         goto have_info;
3073                 }
3074
3075                 goto out;
3076         }
3077
3078         if (info->offset == offset) {
3079                 ret = 1;
3080                 goto out;
3081         }
3082
3083         if (offset > info->offset && offset < info->offset + info->bytes)
3084                 ret = 1;
3085 out:
3086         spin_unlock(&ctl->tree_lock);
3087         return ret;
3088 }
3089
3090 /*
3091  * Use this if you need to make a bitmap or extent entry specifically, it
3092  * doesn't do any of the merging that add_free_space does, this acts a lot like
3093  * how the free space cache loading stuff works, so you can get really weird
3094  * configurations.
3095  */
3096 static int add_free_space_entry(struct btrfs_block_group_cache *cache,
3097                                 u64 offset, u64 bytes, bool bitmap)
3098 {
3099         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3100         struct btrfs_free_space *info = NULL, *bitmap_info;
3101         void *map = NULL;
3102         u64 bytes_added;
3103         int ret;
3104
3105 again:
3106         if (!info) {
3107                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3108                 if (!info)
3109                         return -ENOMEM;
3110         }
3111
3112         if (!bitmap) {
3113                 spin_lock(&ctl->tree_lock);
3114                 info->offset = offset;
3115                 info->bytes = bytes;
3116                 ret = link_free_space(ctl, info);
3117                 spin_unlock(&ctl->tree_lock);
3118                 if (ret)
3119                         kmem_cache_free(btrfs_free_space_cachep, info);
3120                 return ret;
3121         }
3122
3123         if (!map) {
3124                 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3125                 if (!map) {
3126                         kmem_cache_free(btrfs_free_space_cachep, info);
3127                         return -ENOMEM;
3128                 }
3129         }
3130
3131         spin_lock(&ctl->tree_lock);
3132         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3133                                          1, 0);
3134         if (!bitmap_info) {
3135                 info->bitmap = map;
3136                 map = NULL;
3137                 add_new_bitmap(ctl, info, offset);
3138                 bitmap_info = info;
3139         }
3140
3141         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3142         bytes -= bytes_added;
3143         offset += bytes_added;
3144         spin_unlock(&ctl->tree_lock);
3145
3146         if (bytes)
3147                 goto again;
3148
3149         if (map)
3150                 kfree(map);
3151         return 0;
3152 }
3153
3154 /*
3155  * This test just does basic sanity checking, making sure we can add an exten
3156  * entry and remove space from either end and the middle, and make sure we can
3157  * remove space that covers adjacent extent entries.
3158  */
3159 static int test_extents(struct btrfs_block_group_cache *cache)
3160 {
3161         int ret = 0;
3162
3163         printk(KERN_ERR "Running extent only tests\n");
3164
3165         /* First just make sure we can remove an entire entry */
3166         ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
3167         if (ret) {
3168                 printk(KERN_ERR "Error adding initial extents %d\n", ret);
3169                 return ret;
3170         }
3171
3172         ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
3173         if (ret) {
3174                 printk(KERN_ERR "Error removing extent %d\n", ret);
3175                 return ret;
3176         }
3177
3178         if (check_exists(cache, 0, 4 * 1024 * 1024)) {
3179                 printk(KERN_ERR "Full remove left some lingering space\n");
3180                 return -1;
3181         }
3182
3183         /* Ok edge and middle cases now */
3184         ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
3185         if (ret) {
3186                 printk(KERN_ERR "Error adding half extent %d\n", ret);
3187                 return ret;
3188         }
3189
3190         ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 1 * 1024 * 1024);
3191         if (ret) {
3192                 printk(KERN_ERR "Error removing tail end %d\n", ret);
3193                 return ret;
3194         }
3195
3196         ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
3197         if (ret) {
3198                 printk(KERN_ERR "Error removing front end %d\n", ret);
3199                 return ret;
3200         }
3201
3202         ret = btrfs_remove_free_space(cache, 2 * 1024 * 1024, 4096);
3203         if (ret) {
3204                 printk(KERN_ERR "Error removing middle peice %d\n", ret);
3205                 return ret;
3206         }
3207
3208         if (check_exists(cache, 0, 1 * 1024 * 1024)) {
3209                 printk(KERN_ERR "Still have space at the front\n");
3210                 return -1;
3211         }
3212
3213         if (check_exists(cache, 2 * 1024 * 1024, 4096)) {
3214                 printk(KERN_ERR "Still have space in the middle\n");
3215                 return -1;
3216         }
3217
3218         if (check_exists(cache, 3 * 1024 * 1024, 1 * 1024 * 1024)) {
3219                 printk(KERN_ERR "Still have space at the end\n");
3220                 return -1;
3221         }
3222
3223         /* Cleanup */
3224         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3225
3226         return 0;
3227 }
3228
3229 static int test_bitmaps(struct btrfs_block_group_cache *cache)
3230 {
3231         u64 next_bitmap_offset;
3232         int ret;
3233
3234         printk(KERN_ERR "Running bitmap only tests\n");
3235
3236         ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
3237         if (ret) {
3238                 printk(KERN_ERR "Couldn't create a bitmap entry %d\n", ret);
3239                 return ret;
3240         }
3241
3242         ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
3243         if (ret) {
3244                 printk(KERN_ERR "Error removing bitmap full range %d\n", ret);
3245                 return ret;
3246         }
3247
3248         if (check_exists(cache, 0, 4 * 1024 * 1024)) {
3249                 printk(KERN_ERR "Left some space in bitmap\n");
3250                 return -1;
3251         }
3252
3253         ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
3254         if (ret) {
3255                 printk(KERN_ERR "Couldn't add to our bitmap entry %d\n", ret);
3256                 return ret;
3257         }
3258
3259         ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 2 * 1024 * 1024);
3260         if (ret) {
3261                 printk(KERN_ERR "Couldn't remove middle chunk %d\n", ret);
3262                 return ret;
3263         }
3264
3265         /*
3266          * The first bitmap we have starts at offset 0 so the next one is just
3267          * at the end of the first bitmap.
3268          */
3269         next_bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
3270
3271         /* Test a bit straddling two bitmaps */
3272         ret = add_free_space_entry(cache, next_bitmap_offset -
3273                                    (2 * 1024 * 1024), 4 * 1024 * 1024, 1);
3274         if (ret) {
3275                 printk(KERN_ERR "Couldn't add space that straddles two bitmaps"
3276                        " %d\n", ret);
3277                 return ret;
3278         }
3279
3280         ret = btrfs_remove_free_space(cache, next_bitmap_offset -
3281                                       (1 * 1024 * 1024), 2 * 1024 * 1024);
3282         if (ret) {
3283                 printk(KERN_ERR "Couldn't remove overlapping space %d\n", ret);
3284                 return ret;
3285         }
3286
3287         if (check_exists(cache, next_bitmap_offset - (1 * 1024 * 1024),
3288                          2 * 1024 * 1024)) {
3289                 printk(KERN_ERR "Left some space when removing overlapping\n");
3290                 return -1;
3291         }
3292
3293         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3294
3295         return 0;
3296 }
3297
3298 /* This is the high grade jackassery */
3299 static int test_bitmaps_and_extents(struct btrfs_block_group_cache *cache)
3300 {
3301         u64 bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
3302         int ret;
3303
3304         printk(KERN_ERR "Running bitmap and extent tests\n");
3305
3306         /*
3307          * First let's do something simple, an extent at the same offset as the
3308          * bitmap, but the free space completely in the extent and then
3309          * completely in the bitmap.
3310          */
3311         ret = add_free_space_entry(cache, 4 * 1024 * 1024, 1 * 1024 * 1024, 1);
3312         if (ret) {
3313                 printk(KERN_ERR "Couldn't create bitmap entry %d\n", ret);
3314                 return ret;
3315         }
3316
3317         ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
3318         if (ret) {
3319                 printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
3320                 return ret;
3321         }
3322
3323         ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
3324         if (ret) {
3325                 printk(KERN_ERR "Couldn't remove extent entry %d\n", ret);
3326                 return ret;
3327         }
3328
3329         if (check_exists(cache, 0, 1 * 1024 * 1024)) {
3330                 printk(KERN_ERR "Left remnants after our remove\n");
3331                 return -1;
3332         }
3333
3334         /* Now to add back the extent entry and remove from the bitmap */
3335         ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
3336         if (ret) {
3337                 printk(KERN_ERR "Couldn't re-add extent entry %d\n", ret);
3338                 return ret;
3339         }
3340
3341         ret = btrfs_remove_free_space(cache, 4 * 1024 * 1024, 1 * 1024 * 1024);
3342         if (ret) {
3343                 printk(KERN_ERR "Couldn't remove from bitmap %d\n", ret);
3344                 return ret;
3345         }
3346
3347         if (check_exists(cache, 4 * 1024 * 1024, 1 * 1024 * 1024)) {
3348                 printk(KERN_ERR "Left remnants in the bitmap\n");
3349                 return -1;
3350         }
3351
3352         /*
3353          * Ok so a little more evil, extent entry and bitmap at the same offset,
3354          * removing an overlapping chunk.
3355          */
3356         ret = add_free_space_entry(cache, 1 * 1024 * 1024, 4 * 1024 * 1024, 1);
3357         if (ret) {
3358                 printk(KERN_ERR "Couldn't add to a bitmap %d\n", ret);
3359                 return ret;
3360         }
3361
3362         ret = btrfs_remove_free_space(cache, 512 * 1024, 3 * 1024 * 1024);
3363         if (ret) {
3364                 printk(KERN_ERR "Couldn't remove overlapping space %d\n", ret);
3365                 return ret;
3366         }
3367
3368         if (check_exists(cache, 512 * 1024, 3 * 1024 * 1024)) {
3369                 printk(KERN_ERR "Left over peices after removing "
3370                        "overlapping\n");
3371                 return -1;
3372         }
3373
3374         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3375
3376         /* Now with the extent entry offset into the bitmap */
3377         ret = add_free_space_entry(cache, 4 * 1024 * 1024, 4 * 1024 * 1024, 1);
3378         if (ret) {
3379                 printk(KERN_ERR "Couldn't add space to the bitmap %d\n", ret);
3380                 return ret;
3381         }
3382
3383         ret = add_free_space_entry(cache, 2 * 1024 * 1024, 2 * 1024 * 1024, 0);
3384         if (ret) {
3385                 printk(KERN_ERR "Couldn't add extent to the cache %d\n", ret);
3386                 return ret;
3387         }
3388
3389         ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 4 * 1024 * 1024);
3390         if (ret) {
3391                 printk(KERN_ERR "Problem removing overlapping space %d\n", ret);
3392                 return ret;
3393         }
3394
3395         if (check_exists(cache, 3 * 1024 * 1024, 4 * 1024 * 1024)) {
3396                 printk(KERN_ERR "Left something behind when removing space");
3397                 return -1;
3398         }
3399
3400         /*
3401          * This has blown up in the past, the extent entry starts before the
3402          * bitmap entry, but we're trying to remove an offset that falls
3403          * completely within the bitmap range and is in both the extent entry
3404          * and the bitmap entry, looks like this
3405          *
3406          *   [ extent ]
3407          *      [ bitmap ]
3408          *        [ del ]
3409          */
3410         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3411         ret = add_free_space_entry(cache, bitmap_offset + 4 * 1024 * 1024,
3412                                    4 * 1024 * 1024, 1);
3413         if (ret) {
3414                 printk(KERN_ERR "Couldn't add bitmap %d\n", ret);
3415                 return ret;
3416         }
3417
3418         ret = add_free_space_entry(cache, bitmap_offset - 1 * 1024 * 1024,
3419                                    5 * 1024 * 1024, 0);
3420         if (ret) {
3421                 printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
3422                 return ret;
3423         }
3424
3425         ret = btrfs_remove_free_space(cache, bitmap_offset + 1 * 1024 * 1024,
3426                                       5 * 1024 * 1024);
3427         if (ret) {
3428                 printk(KERN_ERR "Failed to free our space %d\n", ret);
3429                 return ret;
3430         }
3431
3432         if (check_exists(cache, bitmap_offset + 1 * 1024 * 1024,
3433                          5 * 1024 * 1024)) {
3434                 printk(KERN_ERR "Left stuff over\n");
3435                 return -1;
3436         }
3437
3438         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3439
3440         /*
3441          * This blew up before, we have part of the free space in a bitmap and
3442          * then the entirety of the rest of the space in an extent.  This used
3443          * to return -EAGAIN back from btrfs_remove_extent, make sure this
3444          * doesn't happen.
3445          */
3446         ret = add_free_space_entry(cache, 1 * 1024 * 1024, 2 * 1024 * 1024, 1);
3447         if (ret) {
3448                 printk(KERN_ERR "Couldn't add bitmap entry %d\n", ret);
3449                 return ret;
3450         }
3451
3452         ret = add_free_space_entry(cache, 3 * 1024 * 1024, 1 * 1024 * 1024, 0);
3453         if (ret) {
3454                 printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
3455                 return ret;
3456         }
3457
3458         ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 3 * 1024 * 1024);
3459         if (ret) {
3460                 printk(KERN_ERR "Error removing bitmap and extent "
3461                        "overlapping %d\n", ret);
3462                 return ret;
3463         }
3464
3465         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3466         return 0;
3467 }
3468
3469 void btrfs_test_free_space_cache(void)
3470 {
3471         struct btrfs_block_group_cache *cache;
3472
3473         printk(KERN_ERR "Running btrfs free space cache tests\n");
3474
3475         cache = init_test_block_group();
3476         if (!cache) {
3477                 printk(KERN_ERR "Couldn't run the tests\n");
3478                 return;
3479         }
3480
3481         if (test_extents(cache))
3482                 goto out;
3483         if (test_bitmaps(cache))
3484                 goto out;
3485         if (test_bitmaps_and_extents(cache))
3486                 goto out;
3487 out:
3488         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3489         kfree(cache->free_space_ctl);
3490         kfree(cache);
3491         printk(KERN_ERR "Free space cache tests finished\n");
3492 }
3493 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */