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                 WARN_ON(1);
 925                 goto out_nospc;
 926         }
 927
 928         io_ctl_set_generation(&io_ctl, trans->transid);
 929
 930         /* Write out the extent entries */
 931         while (node) {
 932                 struct btrfs_free_space *e;
 933
 934                 e = rb_entry(node, struct btrfs_free_space, offset_index);
 935                 entries++;
 936
 937                 ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes,
 938                                        e->bitmap);
 939                 if (ret)
 940                         goto out_nospc;
 941
 942                 if (e->bitmap) {
 943                         list_add_tail(&e->list, &bitmap_list);
 944                         bitmaps++;
 945                 }
 946                 node = rb_next(node);
 947                 if (!node && cluster) {
 948                         node = rb_first(&cluster->root);
 949                         cluster = NULL;
 950                 }
 951         }
 952
 953         /*
 954          * We want to add any pinned extents to our free space cache
 955          * so we don't leak the space
 956          */
 957
 958         /*
 959          * We shouldn't have switched the pinned extents yet so this is the
 960          * right one
 961          */
 962         unpin = root->fs_info->pinned_extents;
 963
 964         if (block_group)
 965                 start = block_group->key.objectid;
 966
 967         while (block_group && (start < block_group->key.objectid +
 968                                block_group->key.offset)) {
 969                 ret = find_first_extent_bit(unpin, start,
 970                                             &extent_start, &extent_end,
 971                                             EXTENT_DIRTY, NULL);
 972                 if (ret) {
 973                         ret = 0;
 974                         break;
 975                 }
 976
 977                 /* This pinned extent is out of our range */
 978                 if (extent_start >= block_group->key.objectid +
 979                     block_group->key.offset)
 980                         break;
 981
 982                 extent_start = max(extent_start, start);
 983                 extent_end = min(block_group->key.objectid +
 984                                  block_group->key.offset, extent_end + 1);
 985                 len = extent_end - extent_start;
 986
 987                 entries++;
 988                 ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
 989                 if (ret)
 990                         goto out_nospc;
 991
 992                 start = extent_end;
 993         }
 994
 995         /* Write out the bitmaps */
 996         list_for_each_safe(pos, n, &bitmap_list) {
 997                 struct btrfs_free_space *entry =
 998                         list_entry(pos, struct btrfs_free_space, list);
 999
1000                 ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap);
1001                 if (ret)
1002                         goto out_nospc;
1003                 list_del_init(&entry->list);
1004         }
1005
1006         /* Zero out the rest of the pages just to make sure */
1007         io_ctl_zero_remaining_pages(&io_ctl);
1008
1009         ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1010                                 0, i_size_read(inode), &cached_state);
1011         io_ctl_drop_pages(&io_ctl);
1012         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1013                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1014
1015         if (ret)
1016                 goto out;
1017
1018
1019         btrfs_wait_ordered_range(inode, 0, (u64)-1);
1020
1021         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1022         key.offset = offset;
1023         key.type = 0;
1024
1025         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1026         if (ret < 0) {
1027                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1028                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1029                                  GFP_NOFS);
1030                 goto out;
1031         }
1032         leaf = path->nodes[0];
1033         if (ret > 0) {
1034                 struct btrfs_key found_key;
1035                 BUG_ON(!path->slots[0]);
1036                 path->slots[0]--;
1037                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1038                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1039                     found_key.offset != offset) {
1040                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1041                                          inode->i_size - 1,
1042                                          EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1043                                          NULL, GFP_NOFS);
1044                         btrfs_release_path(path);
1045                         goto out;
1046                 }
1047         }
1048
1049         BTRFS_I(inode)->generation = trans->transid;
1050         header = btrfs_item_ptr(leaf, path->slots[0],
1051                                 struct btrfs_free_space_header);
1052         btrfs_set_free_space_entries(leaf, header, entries);
1053         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1054         btrfs_set_free_space_generation(leaf, header, trans->transid);
1055         btrfs_mark_buffer_dirty(leaf);
1056         btrfs_release_path(path);
1057
1058         err = 0;
1059 out:
1060         io_ctl_free(&io_ctl);
1061         if (err) {
1062                 invalidate_inode_pages2(inode->i_mapping);
1063                 BTRFS_I(inode)->generation = 0;
1064         }
1065         btrfs_update_inode(trans, root, inode);
1066         return err;
1067
1068 out_nospc:
1069         list_for_each_safe(pos, n, &bitmap_list) {
1070                 struct btrfs_free_space *entry =
1071                         list_entry(pos, struct btrfs_free_space, list);
1072                 list_del_init(&entry->list);
1073         }
1074         io_ctl_drop_pages(&io_ctl);
1075         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1076                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1077         goto out;
1078 }
1079
1080 int btrfs_write_out_cache(struct btrfs_root *root,
1081                           struct btrfs_trans_handle *trans,
1082                           struct btrfs_block_group_cache *block_group,
1083                           struct btrfs_path *path)
1084 {
1085         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1086         struct inode *inode;
1087         int ret = 0;
1088
1089         root = root->fs_info->tree_root;
1090
1091         spin_lock(&block_group->lock);
1092         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1093                 spin_unlock(&block_group->lock);
1094                 return 0;
1095         }
1096         spin_unlock(&block_group->lock);
1097
1098         inode = lookup_free_space_inode(root, block_group, path);
1099         if (IS_ERR(inode))
1100                 return 0;
1101
1102         ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1103                                       path, block_group->key.objectid);
1104         if (ret) {
1105                 spin_lock(&block_group->lock);
1106                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1107                 spin_unlock(&block_group->lock);
1108                 ret = 0;
1109 #ifdef DEBUG
1110                 btrfs_err(root->fs_info,
1111                         "failed to write free space cache for block group %llu",
1112                         block_group->key.objectid);
1113 #endif
1114         }
1115
1116         iput(inode);
1117         return ret;
1118 }
1119
1120 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1121                                           u64 offset)
1122 {
1123         BUG_ON(offset < bitmap_start);
1124         offset -= bitmap_start;
1125         return (unsigned long)(div_u64(offset, unit));
1126 }
1127
1128 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1129 {
1130         return (unsigned long)(div_u64(bytes, unit));
1131 }
1132
1133 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1134                                    u64 offset)
1135 {
1136         u64 bitmap_start;
1137         u64 bytes_per_bitmap;
1138
1139         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1140         bitmap_start = offset - ctl->start;
1141         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1142         bitmap_start *= bytes_per_bitmap;
1143         bitmap_start += ctl->start;
1144
1145         return bitmap_start;
1146 }
1147
1148 static int tree_insert_offset(struct rb_root *root, u64 offset,
1149                               struct rb_node *node, int bitmap)
1150 {
1151         struct rb_node **p = &root->rb_node;
1152         struct rb_node *parent = NULL;
1153         struct btrfs_free_space *info;
1154
1155         while (*p) {
1156                 parent = *p;
1157                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1158
1159                 if (offset < info->offset) {
1160                         p = &(*p)->rb_left;
1161                 } else if (offset > info->offset) {
1162                         p = &(*p)->rb_right;
1163                 } else {
1164                         /*
1165                          * we could have a bitmap entry and an extent entry
1166                          * share the same offset.  If this is the case, we want
1167                          * the extent entry to always be found first if we do a
1168                          * linear search through the tree, since we want to have
1169                          * the quickest allocation time, and allocating from an
1170                          * extent is faster than allocating from a bitmap.  So
1171                          * if we're inserting a bitmap and we find an entry at
1172                          * this offset, we want to go right, or after this entry
1173                          * logically.  If we are inserting an extent and we've
1174                          * found a bitmap, we want to go left, or before
1175                          * logically.
1176                          */
1177                         if (bitmap) {
1178                                 if (info->bitmap) {
1179                                         WARN_ON_ONCE(1);
1180                                         return -EEXIST;
1181                                 }
1182                                 p = &(*p)->rb_right;
1183                         } else {
1184                                 if (!info->bitmap) {
1185                                         WARN_ON_ONCE(1);
1186                                         return -EEXIST;
1187                                 }
1188                                 p = &(*p)->rb_left;
1189                         }
1190                 }
1191         }
1192
1193         rb_link_node(node, parent, p);
1194         rb_insert_color(node, root);
1195
1196         return 0;
1197 }
1198
1199 /*
1200  * searches the tree for the given offset.
1201  *
1202  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1203  * want a section that has at least bytes size and comes at or after the given
1204  * offset.
1205  */
1206 static struct btrfs_free_space *
1207 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1208                    u64 offset, int bitmap_only, int fuzzy)
1209 {
1210         struct rb_node *n = ctl->free_space_offset.rb_node;
1211         struct btrfs_free_space *entry, *prev = NULL;
1212
1213         /* find entry that is closest to the 'offset' */
1214         while (1) {
1215                 if (!n) {
1216                         entry = NULL;
1217                         break;
1218                 }
1219
1220                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1221                 prev = entry;
1222
1223                 if (offset < entry->offset)
1224                         n = n->rb_left;
1225                 else if (offset > entry->offset)
1226                         n = n->rb_right;
1227                 else
1228                         break;
1229         }
1230
1231         if (bitmap_only) {
1232                 if (!entry)
1233                         return NULL;
1234                 if (entry->bitmap)
1235                         return entry;
1236
1237                 /*
1238                  * bitmap entry and extent entry may share same offset,
1239                  * in that case, bitmap entry comes after extent entry.
1240                  */
1241                 n = rb_next(n);
1242                 if (!n)
1243                         return NULL;
1244                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1245                 if (entry->offset != offset)
1246                         return NULL;
1247
1248                 WARN_ON(!entry->bitmap);
1249                 return entry;
1250         } else if (entry) {
1251                 if (entry->bitmap) {
1252                         /*
1253                          * if previous extent entry covers the offset,
1254                          * we should return it instead of the bitmap entry
1255                          */
1256                         n = rb_prev(&entry->offset_index);
1257                         if (n) {
1258                                 prev = rb_entry(n, struct btrfs_free_space,
1259                                                 offset_index);
1260                                 if (!prev->bitmap &&
1261                                     prev->offset + prev->bytes > offset)
1262                                         entry = prev;
1263                         }
1264                 }
1265                 return entry;
1266         }
1267
1268         if (!prev)
1269                 return NULL;
1270
1271         /* find last entry before the 'offset' */
1272         entry = prev;
1273         if (entry->offset > offset) {
1274                 n = rb_prev(&entry->offset_index);
1275                 if (n) {
1276                         entry = rb_entry(n, struct btrfs_free_space,
1277                                         offset_index);
1278                         BUG_ON(entry->offset > offset);
1279                 } else {
1280                         if (fuzzy)
1281                                 return entry;
1282                         else
1283                                 return NULL;
1284                 }
1285         }
1286
1287         if (entry->bitmap) {
1288                 n = rb_prev(&entry->offset_index);
1289                 if (n) {
1290                         prev = rb_entry(n, struct btrfs_free_space,
1291                                         offset_index);
1292                         if (!prev->bitmap &&
1293                             prev->offset + prev->bytes > offset)
1294                                 return prev;
1295                 }
1296                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1297                         return entry;
1298         } else if (entry->offset + entry->bytes > offset)
1299                 return entry;
1300
1301         if (!fuzzy)
1302                 return NULL;
1303
1304         while (1) {
1305                 if (entry->bitmap) {
1306                         if (entry->offset + BITS_PER_BITMAP *
1307                             ctl->unit > offset)
1308                                 break;
1309                 } else {
1310                         if (entry->offset + entry->bytes > offset)
1311                                 break;
1312                 }
1313
1314                 n = rb_next(&entry->offset_index);
1315                 if (!n)
1316                         return NULL;
1317                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1318         }
1319         return entry;
1320 }
1321
1322 static inline void
1323 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1324                     struct btrfs_free_space *info)
1325 {
1326         rb_erase(&info->offset_index, &ctl->free_space_offset);
1327         ctl->free_extents--;
1328 }
1329
1330 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1331                               struct btrfs_free_space *info)
1332 {
1333         __unlink_free_space(ctl, info);
1334         ctl->free_space -= info->bytes;
1335 }
1336
1337 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1338                            struct btrfs_free_space *info)
1339 {
1340         int ret = 0;
1341
1342         BUG_ON(!info->bitmap && !info->bytes);
1343         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1344                                  &info->offset_index, (info->bitmap != NULL));
1345         if (ret)
1346                 return ret;
1347
1348         ctl->free_space += info->bytes;
1349         ctl->free_extents++;
1350         return ret;
1351 }
1352
1353 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1354 {
1355         struct btrfs_block_group_cache *block_group = ctl->private;
1356         u64 max_bytes;
1357         u64 bitmap_bytes;
1358         u64 extent_bytes;
1359         u64 size = block_group->key.offset;
1360         u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1361         int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1362
1363         max_bitmaps = max(max_bitmaps, 1);
1364
1365         BUG_ON(ctl->total_bitmaps > max_bitmaps);
1366
1367         /*
1368          * The goal is to keep the total amount of memory used per 1gb of space
1369          * at or below 32k, so we need to adjust how much memory we allow to be
1370          * used by extent based free space tracking
1371          */
1372         if (size < 1024 * 1024 * 1024)
1373                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1374         else
1375                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1376                         div64_u64(size, 1024 * 1024 * 1024);
1377
1378         /*
1379          * we want to account for 1 more bitmap than what we have so we can make
1380          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1381          * we add more bitmaps.
1382          */
1383         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1384
1385         if (bitmap_bytes >= max_bytes) {
1386                 ctl->extents_thresh = 0;
1387                 return;
1388         }
1389
1390         /*
1391          * we want the extent entry threshold to always be at most 1/2 the maxw
1392          * bytes we can have, or whatever is less than that.
1393          */
1394         extent_bytes = max_bytes - bitmap_bytes;
1395         extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1396
1397         ctl->extents_thresh =
1398                 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1399 }
1400
1401 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1402                                        struct btrfs_free_space *info,
1403                                        u64 offset, u64 bytes)
1404 {
1405         unsigned long start, count;
1406
1407         start = offset_to_bit(info->offset, ctl->unit, offset);
1408         count = bytes_to_bits(bytes, ctl->unit);
1409         BUG_ON(start + count > BITS_PER_BITMAP);
1410
1411         bitmap_clear(info->bitmap, start, count);
1412
1413         info->bytes -= bytes;
1414 }
1415
1416 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1417                               struct btrfs_free_space *info, u64 offset,
1418                               u64 bytes)
1419 {
1420         __bitmap_clear_bits(ctl, info, offset, bytes);
1421         ctl->free_space -= bytes;
1422 }
1423
1424 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1425                             struct btrfs_free_space *info, u64 offset,
1426                             u64 bytes)
1427 {
1428         unsigned long start, count;
1429
1430         start = offset_to_bit(info->offset, ctl->unit, offset);
1431         count = bytes_to_bits(bytes, ctl->unit);
1432         BUG_ON(start + count > BITS_PER_BITMAP);
1433
1434         bitmap_set(info->bitmap, start, count);
1435
1436         info->bytes += bytes;
1437         ctl->free_space += bytes;
1438 }
1439
1440 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1441                          struct btrfs_free_space *bitmap_info, u64 *offset,
1442                          u64 *bytes)
1443 {
1444         unsigned long found_bits = 0;
1445         unsigned long bits, i;
1446         unsigned long next_zero;
1447
1448         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1449                           max_t(u64, *offset, bitmap_info->offset));
1450         bits = bytes_to_bits(*bytes, ctl->unit);
1451
1452         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1453                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1454                                                BITS_PER_BITMAP, i);
1455                 if ((next_zero - i) >= bits) {
1456                         found_bits = next_zero - i;
1457                         break;
1458                 }
1459                 i = next_zero;
1460         }
1461
1462         if (found_bits) {
1463                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1464                 *bytes = (u64)(found_bits) * ctl->unit;
1465                 return 0;
1466         }
1467
1468         return -1;
1469 }
1470
1471 static struct btrfs_free_space *
1472 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1473                 unsigned long align)
1474 {
1475         struct btrfs_free_space *entry;
1476         struct rb_node *node;
1477         u64 ctl_off;
1478         u64 tmp;
1479         u64 align_off;
1480         int ret;
1481
1482         if (!ctl->free_space_offset.rb_node)
1483                 return NULL;
1484
1485         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1486         if (!entry)
1487                 return NULL;
1488
1489         for (node = &entry->offset_index; node; node = rb_next(node)) {
1490                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1491                 if (entry->bytes < *bytes)
1492                         continue;
1493
1494                 /* make sure the space returned is big enough
1495                  * to match our requested alignment
1496                  */
1497                 if (*bytes >= align) {
1498                         ctl_off = entry->offset - ctl->start;
1499                         tmp = ctl_off + align - 1;;
1500                         do_div(tmp, align);
1501                         tmp = tmp * align + ctl->start;
1502                         align_off = tmp - entry->offset;
1503                 } else {
1504                         align_off = 0;
1505                         tmp = entry->offset;
1506                 }
1507
1508                 if (entry->bytes < *bytes + align_off)
1509                         continue;
1510
1511                 if (entry->bitmap) {
1512                         ret = search_bitmap(ctl, entry, &tmp, bytes);
1513                         if (!ret) {
1514                                 *offset = tmp;
1515                                 return entry;
1516                         }
1517                         continue;
1518                 }
1519
1520                 *offset = tmp;
1521                 *bytes = entry->bytes - align_off;
1522                 return entry;
1523         }
1524
1525         return NULL;
1526 }
1527
1528 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1529                            struct btrfs_free_space *info, u64 offset)
1530 {
1531         info->offset = offset_to_bitmap(ctl, offset);
1532         info->bytes = 0;
1533         INIT_LIST_HEAD(&info->list);
1534         link_free_space(ctl, info);
1535         ctl->total_bitmaps++;
1536
1537         ctl->op->recalc_thresholds(ctl);
1538 }
1539
1540 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1541                         struct btrfs_free_space *bitmap_info)
1542 {
1543         unlink_free_space(ctl, bitmap_info);
1544         kfree(bitmap_info->bitmap);
1545         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1546         ctl->total_bitmaps--;
1547         ctl->op->recalc_thresholds(ctl);
1548 }
1549
1550 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1551                               struct btrfs_free_space *bitmap_info,
1552                               u64 *offset, u64 *bytes)
1553 {
1554         u64 end;
1555         u64 search_start, search_bytes;
1556         int ret;
1557
1558 again:
1559         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1560
1561         /*
1562          * We need to search for bits in this bitmap.  We could only cover some
1563          * of the extent in this bitmap thanks to how we add space, so we need
1564          * to search for as much as it as we can and clear that amount, and then
1565          * go searching for the next bit.
1566          */
1567         search_start = *offset;
1568         search_bytes = ctl->unit;
1569         search_bytes = min(search_bytes, end - search_start + 1);
1570         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1571         if (ret < 0 || search_start != *offset)
1572                 return -EINVAL;
1573
1574         /* We may have found more bits than what we need */
1575         search_bytes = min(search_bytes, *bytes);
1576
1577         /* Cannot clear past the end of the bitmap */
1578         search_bytes = min(search_bytes, end - search_start + 1);
1579
1580         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1581         *offset += search_bytes;
1582         *bytes -= search_bytes;
1583
1584         if (*bytes) {
1585                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1586                 if (!bitmap_info->bytes)
1587                         free_bitmap(ctl, bitmap_info);
1588
1589                 /*
1590                  * no entry after this bitmap, but we still have bytes to
1591                  * remove, so something has gone wrong.
1592                  */
1593                 if (!next)
1594                         return -EINVAL;
1595
1596                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1597                                        offset_index);
1598
1599                 /*
1600                  * if the next entry isn't a bitmap we need to return to let the
1601                  * extent stuff do its work.
1602                  */
1603                 if (!bitmap_info->bitmap)
1604                         return -EAGAIN;
1605
1606                 /*
1607                  * Ok the next item is a bitmap, but it may not actually hold
1608                  * the information for the rest of this free space stuff, so
1609                  * look for it, and if we don't find it return so we can try
1610                  * everything over again.
1611                  */
1612                 search_start = *offset;
1613                 search_bytes = ctl->unit;
1614                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1615                                     &search_bytes);
1616                 if (ret < 0 || search_start != *offset)
1617                         return -EAGAIN;
1618
1619                 goto again;
1620         } else if (!bitmap_info->bytes)
1621                 free_bitmap(ctl, bitmap_info);
1622
1623         return 0;
1624 }
1625
1626 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1627                                struct btrfs_free_space *info, u64 offset,
1628                                u64 bytes)
1629 {
1630         u64 bytes_to_set = 0;
1631         u64 end;
1632
1633         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1634
1635         bytes_to_set = min(end - offset, bytes);
1636
1637         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1638
1639         return bytes_to_set;
1640
1641 }
1642
1643 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1644                       struct btrfs_free_space *info)
1645 {
1646         struct btrfs_block_group_cache *block_group = ctl->private;
1647
1648         /*
1649          * If we are below the extents threshold then we can add this as an
1650          * extent, and don't have to deal with the bitmap
1651          */
1652         if (ctl->free_extents < ctl->extents_thresh) {
1653                 /*
1654                  * If this block group has some small extents we don't want to
1655                  * use up all of our free slots in the cache with them, we want
1656                  * to reserve them to larger extents, however if we have plent
1657                  * of cache left then go ahead an dadd them, no sense in adding
1658                  * the overhead of a bitmap if we don't have to.
1659                  */
1660                 if (info->bytes <= block_group->sectorsize * 4) {
1661                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1662                                 return false;
1663                 } else {
1664                         return false;
1665                 }
1666         }
1667
1668         /*
1669          * The original block groups from mkfs can be really small, like 8
1670          * megabytes, so don't bother with a bitmap for those entries.  However
1671          * some block groups can be smaller than what a bitmap would cover but
1672          * are still large enough that they could overflow the 32k memory limit,
1673          * so allow those block groups to still be allowed to have a bitmap
1674          * entry.
1675          */
1676         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1677                 return false;
1678
1679         return true;
1680 }
1681
1682 static struct btrfs_free_space_op free_space_op = {
1683         .recalc_thresholds      = recalculate_thresholds,
1684         .use_bitmap             = use_bitmap,
1685 };
1686
1687 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1688                               struct btrfs_free_space *info)
1689 {
1690         struct btrfs_free_space *bitmap_info;
1691         struct btrfs_block_group_cache *block_group = NULL;
1692         int added = 0;
1693         u64 bytes, offset, bytes_added;
1694         int ret;
1695
1696         bytes = info->bytes;
1697         offset = info->offset;
1698
1699         if (!ctl->op->use_bitmap(ctl, info))
1700                 return 0;
1701
1702         if (ctl->op == &free_space_op)
1703                 block_group = ctl->private;
1704 again:
1705         /*
1706          * Since we link bitmaps right into the cluster we need to see if we
1707          * have a cluster here, and if so and it has our bitmap we need to add
1708          * the free space to that bitmap.
1709          */
1710         if (block_group && !list_empty(&block_group->cluster_list)) {
1711                 struct btrfs_free_cluster *cluster;
1712                 struct rb_node *node;
1713                 struct btrfs_free_space *entry;
1714
1715                 cluster = list_entry(block_group->cluster_list.next,
1716                                      struct btrfs_free_cluster,
1717                                      block_group_list);
1718                 spin_lock(&cluster->lock);
1719                 node = rb_first(&cluster->root);
1720                 if (!node) {
1721                         spin_unlock(&cluster->lock);
1722                         goto no_cluster_bitmap;
1723                 }
1724
1725                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1726                 if (!entry->bitmap) {
1727                         spin_unlock(&cluster->lock);
1728                         goto no_cluster_bitmap;
1729                 }
1730
1731                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1732                         bytes_added = add_bytes_to_bitmap(ctl, entry,
1733                                                           offset, bytes);
1734                         bytes -= bytes_added;
1735                         offset += bytes_added;
1736                 }
1737                 spin_unlock(&cluster->lock);
1738                 if (!bytes) {
1739                         ret = 1;
1740                         goto out;
1741                 }
1742         }
1743
1744 no_cluster_bitmap:
1745         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1746                                          1, 0);
1747         if (!bitmap_info) {
1748                 BUG_ON(added);
1749                 goto new_bitmap;
1750         }
1751
1752         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1753         bytes -= bytes_added;
1754         offset += bytes_added;
1755         added = 0;
1756
1757         if (!bytes) {
1758                 ret = 1;
1759                 goto out;
1760         } else
1761                 goto again;
1762
1763 new_bitmap:
1764         if (info && info->bitmap) {
1765                 add_new_bitmap(ctl, info, offset);
1766                 added = 1;
1767                 info = NULL;
1768                 goto again;
1769         } else {
1770                 spin_unlock(&ctl->tree_lock);
1771
1772                 /* no pre-allocated info, allocate a new one */
1773                 if (!info) {
1774                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
1775                                                  GFP_NOFS);
1776                         if (!info) {
1777                                 spin_lock(&ctl->tree_lock);
1778                                 ret = -ENOMEM;
1779                                 goto out;
1780                         }
1781                 }
1782
1783                 /* allocate the bitmap */
1784                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1785                 spin_lock(&ctl->tree_lock);
1786                 if (!info->bitmap) {
1787                         ret = -ENOMEM;
1788                         goto out;
1789                 }
1790                 goto again;
1791         }
1792
1793 out:
1794         if (info) {
1795                 if (info->bitmap)
1796                         kfree(info->bitmap);
1797                 kmem_cache_free(btrfs_free_space_cachep, info);
1798         }
1799
1800         return ret;
1801 }
1802
1803 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1804                           struct btrfs_free_space *info, bool update_stat)
1805 {
1806         struct btrfs_free_space *left_info;
1807         struct btrfs_free_space *right_info;
1808         bool merged = false;
1809         u64 offset = info->offset;
1810         u64 bytes = info->bytes;
1811
1812         /*
1813          * first we want to see if there is free space adjacent to the range we
1814          * are adding, if there is remove that struct and add a new one to
1815          * cover the entire range
1816          */
1817         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1818         if (right_info && rb_prev(&right_info->offset_index))
1819                 left_info = rb_entry(rb_prev(&right_info->offset_index),
1820                                      struct btrfs_free_space, offset_index);
1821         else
1822                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1823
1824         if (right_info && !right_info->bitmap) {
1825                 if (update_stat)
1826                         unlink_free_space(ctl, right_info);
1827                 else
1828                         __unlink_free_space(ctl, right_info);
1829                 info->bytes += right_info->bytes;
1830                 kmem_cache_free(btrfs_free_space_cachep, right_info);
1831                 merged = true;
1832         }
1833
1834         if (left_info && !left_info->bitmap &&
1835             left_info->offset + left_info->bytes == offset) {
1836                 if (update_stat)
1837                         unlink_free_space(ctl, left_info);
1838                 else
1839                         __unlink_free_space(ctl, left_info);
1840                 info->offset = left_info->offset;
1841                 info->bytes += left_info->bytes;
1842                 kmem_cache_free(btrfs_free_space_cachep, left_info);
1843                 merged = true;
1844         }
1845
1846         return merged;
1847 }
1848
1849 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1850                            u64 offset, u64 bytes)
1851 {
1852         struct btrfs_free_space *info;
1853         int ret = 0;
1854
1855         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1856         if (!info)
1857                 return -ENOMEM;
1858
1859         info->offset = offset;
1860         info->bytes = bytes;
1861
1862         spin_lock(&ctl->tree_lock);
1863
1864         if (try_merge_free_space(ctl, info, true))
1865                 goto link;
1866
1867         /*
1868          * There was no extent directly to the left or right of this new
1869          * extent then we know we're going to have to allocate a new extent, so
1870          * before we do that see if we need to drop this into a bitmap
1871          */
1872         ret = insert_into_bitmap(ctl, info);
1873         if (ret < 0) {
1874                 goto out;
1875         } else if (ret) {
1876                 ret = 0;
1877                 goto out;
1878         }
1879 link:
1880         ret = link_free_space(ctl, info);
1881         if (ret)
1882                 kmem_cache_free(btrfs_free_space_cachep, info);
1883 out:
1884         spin_unlock(&ctl->tree_lock);
1885
1886         if (ret) {
1887                 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1888                 BUG_ON(ret == -EEXIST);
1889         }
1890
1891         return ret;
1892 }
1893
1894 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1895                             u64 offset, u64 bytes)
1896 {
1897         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1898         struct btrfs_free_space *info;
1899         int ret;
1900         bool re_search = false;
1901
1902         spin_lock(&ctl->tree_lock);
1903
1904 again:
1905         ret = 0;
1906         if (!bytes)
1907                 goto out_lock;
1908
1909         info = tree_search_offset(ctl, offset, 0, 0);
1910         if (!info) {
1911                 /*
1912                  * oops didn't find an extent that matched the space we wanted
1913                  * to remove, look for a bitmap instead
1914                  */
1915                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1916                                           1, 0);
1917                 if (!info) {
1918                         /*
1919                          * If we found a partial bit of our free space in a
1920                          * bitmap but then couldn't find the other part this may
1921                          * be a problem, so WARN about it.
1922                          */
1923                         WARN_ON(re_search);
1924                         goto out_lock;
1925                 }
1926         }
1927
1928         re_search = false;
1929         if (!info->bitmap) {
1930                 unlink_free_space(ctl, info);
1931                 if (offset == info->offset) {
1932                         u64 to_free = min(bytes, info->bytes);
1933
1934                         info->bytes -= to_free;
1935                         info->offset += to_free;
1936                         if (info->bytes) {
1937                                 ret = link_free_space(ctl, info);
1938                                 WARN_ON(ret);
1939                         } else {
1940                                 kmem_cache_free(btrfs_free_space_cachep, info);
1941                         }
1942
1943                         offset += to_free;
1944                         bytes -= to_free;
1945                         goto again;
1946                 } else {
1947                         u64 old_end = info->bytes + info->offset;
1948
1949                         info->bytes = offset - info->offset;
1950                         ret = link_free_space(ctl, info);
1951                         WARN_ON(ret);
1952                         if (ret)
1953                                 goto out_lock;
1954
1955                         /* Not enough bytes in this entry to satisfy us */
1956                         if (old_end < offset + bytes) {
1957                                 bytes -= old_end - offset;
1958                                 offset = old_end;
1959                                 goto again;
1960                         } else if (old_end == offset + bytes) {
1961                                 /* all done */
1962                                 goto out_lock;
1963                         }
1964                         spin_unlock(&ctl->tree_lock);
1965
1966                         ret = btrfs_add_free_space(block_group, offset + bytes,
1967                                                    old_end - (offset + bytes));
1968                         WARN_ON(ret);
1969                         goto out;
1970                 }
1971         }
1972
1973         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1974         if (ret == -EAGAIN) {
1975                 re_search = true;
1976                 goto again;
1977         }
1978 out_lock:
1979         spin_unlock(&ctl->tree_lock);
1980 out:
1981         return ret;
1982 }
1983
1984 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1985                            u64 bytes)
1986 {
1987         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1988         struct btrfs_free_space *info;
1989         struct rb_node *n;
1990         int count = 0;
1991
1992         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1993                 info = rb_entry(n, struct btrfs_free_space, offset_index);
1994                 if (info->bytes >= bytes && !block_group->ro)
1995                         count++;
1996                 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1997                        (unsigned long long)info->offset,
1998                        (unsigned long long)info->bytes,
1999                        (info->bitmap) ? "yes" : "no");
2000         }
2001         printk(KERN_INFO "block group has cluster?: %s\n",
2002                list_empty(&block_group->cluster_list) ? "no" : "yes");
2003         printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
2004                "\n", count);
2005 }
2006
2007 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2008 {
2009         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2010
2011         spin_lock_init(&ctl->tree_lock);
2012         ctl->unit = block_group->sectorsize;
2013         ctl->start = block_group->key.objectid;
2014         ctl->private = block_group;
2015         ctl->op = &free_space_op;
2016
2017         /*
2018          * we only want to have 32k of ram per block group for keeping
2019          * track of free space, and if we pass 1/2 of that we want to
2020          * start converting things over to using bitmaps
2021          */
2022         ctl->extents_thresh = ((1024 * 32) / 2) /
2023                                 sizeof(struct btrfs_free_space);
2024 }
2025
2026 /*
2027  * for a given cluster, put all of its extents back into the free
2028  * space cache.  If the block group passed doesn't match the block group
2029  * pointed to by the cluster, someone else raced in and freed the
2030  * cluster already.  In that case, we just return without changing anything
2031  */
2032 static int
2033 __btrfs_return_cluster_to_free_space(
2034                              struct btrfs_block_group_cache *block_group,
2035                              struct btrfs_free_cluster *cluster)
2036 {
2037         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2038         struct btrfs_free_space *entry;
2039         struct rb_node *node;
2040
2041         spin_lock(&cluster->lock);
2042         if (cluster->block_group != block_group)
2043                 goto out;
2044
2045         cluster->block_group = NULL;
2046         cluster->window_start = 0;
2047         list_del_init(&cluster->block_group_list);
2048
2049         node = rb_first(&cluster->root);
2050         while (node) {
2051                 bool bitmap;
2052
2053                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2054                 node = rb_next(&entry->offset_index);
2055                 rb_erase(&entry->offset_index, &cluster->root);
2056
2057                 bitmap = (entry->bitmap != NULL);
2058                 if (!bitmap)
2059                         try_merge_free_space(ctl, entry, false);
2060                 tree_insert_offset(&ctl->free_space_offset,
2061                                    entry->offset, &entry->offset_index, bitmap);
2062         }
2063         cluster->root = RB_ROOT;
2064
2065 out:
2066         spin_unlock(&cluster->lock);
2067         btrfs_put_block_group(block_group);
2068         return 0;
2069 }
2070
2071 static void __btrfs_remove_free_space_cache_locked(
2072                                 struct btrfs_free_space_ctl *ctl)
2073 {
2074         struct btrfs_free_space *info;
2075         struct rb_node *node;
2076
2077         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2078                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2079                 if (!info->bitmap) {
2080                         unlink_free_space(ctl, info);
2081                         kmem_cache_free(btrfs_free_space_cachep, info);
2082                 } else {
2083                         free_bitmap(ctl, info);
2084                 }
2085                 if (need_resched()) {
2086                         spin_unlock(&ctl->tree_lock);
2087                         cond_resched();
2088                         spin_lock(&ctl->tree_lock);
2089                 }
2090         }
2091 }
2092
2093 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2094 {
2095         spin_lock(&ctl->tree_lock);
2096         __btrfs_remove_free_space_cache_locked(ctl);
2097         spin_unlock(&ctl->tree_lock);
2098 }
2099
2100 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2101 {
2102         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2103         struct btrfs_free_cluster *cluster;
2104         struct list_head *head;
2105
2106         spin_lock(&ctl->tree_lock);
2107         while ((head = block_group->cluster_list.next) !=
2108                &block_group->cluster_list) {
2109                 cluster = list_entry(head, struct btrfs_free_cluster,
2110                                      block_group_list);
2111
2112                 WARN_ON(cluster->block_group != block_group);
2113                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2114                 if (need_resched()) {
2115                         spin_unlock(&ctl->tree_lock);
2116                         cond_resched();
2117                         spin_lock(&ctl->tree_lock);
2118                 }
2119         }
2120         __btrfs_remove_free_space_cache_locked(ctl);
2121         spin_unlock(&ctl->tree_lock);
2122
2123 }
2124
2125 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2126                                u64 offset, u64 bytes, u64 empty_size)
2127 {
2128         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2129         struct btrfs_free_space *entry = NULL;
2130         u64 bytes_search = bytes + empty_size;
2131         u64 ret = 0;
2132         u64 align_gap = 0;
2133         u64 align_gap_len = 0;
2134
2135         spin_lock(&ctl->tree_lock);
2136         entry = find_free_space(ctl, &offset, &bytes_search,
2137                                 block_group->full_stripe_len);
2138         if (!entry)
2139                 goto out;
2140
2141         ret = offset;
2142         if (entry->bitmap) {
2143                 bitmap_clear_bits(ctl, entry, offset, bytes);
2144                 if (!entry->bytes)
2145                         free_bitmap(ctl, entry);
2146         } else {
2147
2148                 unlink_free_space(ctl, entry);
2149                 align_gap_len = offset - entry->offset;
2150                 align_gap = entry->offset;
2151
2152                 entry->offset = offset + bytes;
2153                 WARN_ON(entry->bytes < bytes + align_gap_len);
2154
2155                 entry->bytes -= bytes + align_gap_len;
2156                 if (!entry->bytes)
2157                         kmem_cache_free(btrfs_free_space_cachep, entry);
2158                 else
2159                         link_free_space(ctl, entry);
2160         }
2161
2162 out:
2163         spin_unlock(&ctl->tree_lock);
2164
2165         if (align_gap_len)
2166                 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2167         return ret;
2168 }
2169
2170 /*
2171  * given a cluster, put all of its extents back into the free space
2172  * cache.  If a block group is passed, this function will only free
2173  * a cluster that belongs to the passed block group.
2174  *
2175  * Otherwise, it'll get a reference on the block group pointed to by the
2176  * cluster and remove the cluster from it.
2177  */
2178 int btrfs_return_cluster_to_free_space(
2179                                struct btrfs_block_group_cache *block_group,
2180                                struct btrfs_free_cluster *cluster)
2181 {
2182         struct btrfs_free_space_ctl *ctl;
2183         int ret;
2184
2185         /* first, get a safe pointer to the block group */
2186         spin_lock(&cluster->lock);
2187         if (!block_group) {
2188                 block_group = cluster->block_group;
2189                 if (!block_group) {
2190                         spin_unlock(&cluster->lock);
2191                         return 0;
2192                 }
2193         } else if (cluster->block_group != block_group) {
2194                 /* someone else has already freed it don't redo their work */
2195                 spin_unlock(&cluster->lock);
2196                 return 0;
2197         }
2198         atomic_inc(&block_group->count);
2199         spin_unlock(&cluster->lock);
2200
2201         ctl = block_group->free_space_ctl;
2202
2203         /* now return any extents the cluster had on it */
2204         spin_lock(&ctl->tree_lock);
2205         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2206         spin_unlock(&ctl->tree_lock);
2207
2208         /* finally drop our ref */
2209         btrfs_put_block_group(block_group);
2210         return ret;
2211 }
2212
2213 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2214                                    struct btrfs_free_cluster *cluster,
2215                                    struct btrfs_free_space *entry,
2216                                    u64 bytes, u64 min_start)
2217 {
2218         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2219         int err;
2220         u64 search_start = cluster->window_start;
2221         u64 search_bytes = bytes;
2222         u64 ret = 0;
2223
2224         search_start = min_start;
2225         search_bytes = bytes;
2226
2227         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2228         if (err)
2229                 return 0;
2230
2231         ret = search_start;
2232         __bitmap_clear_bits(ctl, entry, ret, bytes);
2233
2234         return ret;
2235 }
2236
2237 /*
2238  * given a cluster, try to allocate 'bytes' from it, returns 0
2239  * if it couldn't find anything suitably large, or a logical disk offset
2240  * if things worked out
2241  */
2242 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2243                              struct btrfs_free_cluster *cluster, u64 bytes,
2244                              u64 min_start)
2245 {
2246         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2247         struct btrfs_free_space *entry = NULL;
2248         struct rb_node *node;
2249         u64 ret = 0;
2250
2251         spin_lock(&cluster->lock);
2252         if (bytes > cluster->max_size)
2253                 goto out;
2254
2255         if (cluster->block_group != block_group)
2256                 goto out;
2257
2258         node = rb_first(&cluster->root);
2259         if (!node)
2260                 goto out;
2261
2262         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2263         while(1) {
2264                 if (entry->bytes < bytes ||
2265                     (!entry->bitmap && entry->offset < min_start)) {
2266                         node = rb_next(&entry->offset_index);
2267                         if (!node)
2268                                 break;
2269                         entry = rb_entry(node, struct btrfs_free_space,
2270                                          offset_index);
2271                         continue;
2272                 }
2273
2274                 if (entry->bitmap) {
2275                         ret = btrfs_alloc_from_bitmap(block_group,
2276                                                       cluster, entry, bytes,
2277                                                       cluster->window_start);
2278                         if (ret == 0) {
2279                                 node = rb_next(&entry->offset_index);
2280                                 if (!node)
2281                                         break;
2282                                 entry = rb_entry(node, struct btrfs_free_space,
2283                                                  offset_index);
2284                                 continue;
2285                         }
2286                         cluster->window_start += bytes;
2287                 } else {
2288                         ret = entry->offset;
2289
2290                         entry->offset += bytes;
2291                         entry->bytes -= bytes;
2292                 }
2293
2294                 if (entry->bytes == 0)
2295                         rb_erase(&entry->offset_index, &cluster->root);
2296                 break;
2297         }
2298 out:
2299         spin_unlock(&cluster->lock);
2300
2301         if (!ret)
2302                 return 0;
2303
2304         spin_lock(&ctl->tree_lock);
2305
2306         ctl->free_space -= bytes;
2307         if (entry->bytes == 0) {
2308                 ctl->free_extents--;
2309                 if (entry->bitmap) {
2310                         kfree(entry->bitmap);
2311                         ctl->total_bitmaps--;
2312                         ctl->op->recalc_thresholds(ctl);
2313                 }
2314                 kmem_cache_free(btrfs_free_space_cachep, entry);
2315         }
2316
2317         spin_unlock(&ctl->tree_lock);
2318
2319         return ret;
2320 }
2321
2322 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2323                                 struct btrfs_free_space *entry,
2324                                 struct btrfs_free_cluster *cluster,
2325                                 u64 offset, u64 bytes,
2326                                 u64 cont1_bytes, u64 min_bytes)
2327 {
2328         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2329         unsigned long next_zero;
2330         unsigned long i;
2331         unsigned long want_bits;
2332         unsigned long min_bits;
2333         unsigned long found_bits;
2334         unsigned long start = 0;
2335         unsigned long total_found = 0;
2336         int ret;
2337
2338         i = offset_to_bit(entry->offset, ctl->unit,
2339                           max_t(u64, offset, entry->offset));
2340         want_bits = bytes_to_bits(bytes, ctl->unit);
2341         min_bits = bytes_to_bits(min_bytes, ctl->unit);
2342
2343 again:
2344         found_bits = 0;
2345         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2346                 next_zero = find_next_zero_bit(entry->bitmap,
2347                                                BITS_PER_BITMAP, i);
2348                 if (next_zero - i >= min_bits) {
2349                         found_bits = next_zero - i;
2350                         break;
2351                 }
2352                 i = next_zero;
2353         }
2354
2355         if (!found_bits)
2356                 return -ENOSPC;
2357
2358         if (!total_found) {
2359                 start = i;
2360                 cluster->max_size = 0;
2361         }
2362
2363         total_found += found_bits;
2364
2365         if (cluster->max_size < found_bits * ctl->unit)
2366                 cluster->max_size = found_bits * ctl->unit;
2367
2368         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2369                 i = next_zero + 1;
2370                 goto again;
2371         }
2372
2373         cluster->window_start = start * ctl->unit + entry->offset;
2374         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2375         ret = tree_insert_offset(&cluster->root, entry->offset,
2376                                  &entry->offset_index, 1);
2377         BUG_ON(ret); /* -EEXIST; Logic error */
2378
2379         trace_btrfs_setup_cluster(block_group, cluster,
2380                                   total_found * ctl->unit, 1);
2381         return 0;
2382 }
2383
2384 /*
2385  * This searches the block group for just extents to fill the cluster with.
2386  * Try to find a cluster with at least bytes total bytes, at least one
2387  * extent of cont1_bytes, and other clusters of at least min_bytes.
2388  */
2389 static noinline int
2390 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2391                         struct btrfs_free_cluster *cluster,
2392                         struct list_head *bitmaps, u64 offset, u64 bytes,
2393                         u64 cont1_bytes, u64 min_bytes)
2394 {
2395         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2396         struct btrfs_free_space *first = NULL;
2397         struct btrfs_free_space *entry = NULL;
2398         struct btrfs_free_space *last;
2399         struct rb_node *node;
2400         u64 window_start;
2401         u64 window_free;
2402         u64 max_extent;
2403         u64 total_size = 0;
2404
2405         entry = tree_search_offset(ctl, offset, 0, 1);
2406         if (!entry)
2407                 return -ENOSPC;
2408
2409         /*
2410          * We don't want bitmaps, so just move along until we find a normal
2411          * extent entry.
2412          */
2413         while (entry->bitmap || entry->bytes < min_bytes) {
2414                 if (entry->bitmap && list_empty(&entry->list))
2415                         list_add_tail(&entry->list, bitmaps);
2416                 node = rb_next(&entry->offset_index);
2417                 if (!node)
2418                         return -ENOSPC;
2419                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2420         }
2421
2422         window_start = entry->offset;
2423         window_free = entry->bytes;
2424         max_extent = entry->bytes;
2425         first = entry;
2426         last = entry;
2427
2428         for (node = rb_next(&entry->offset_index); node;
2429              node = rb_next(&entry->offset_index)) {
2430                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2431
2432                 if (entry->bitmap) {
2433                         if (list_empty(&entry->list))
2434                                 list_add_tail(&entry->list, bitmaps);
2435                         continue;
2436                 }
2437
2438                 if (entry->bytes < min_bytes)
2439                         continue;
2440
2441                 last = entry;
2442                 window_free += entry->bytes;
2443                 if (entry->bytes > max_extent)
2444                         max_extent = entry->bytes;
2445         }
2446
2447         if (window_free < bytes || max_extent < cont1_bytes)
2448                 return -ENOSPC;
2449
2450         cluster->window_start = first->offset;
2451
2452         node = &first->offset_index;
2453
2454         /*
2455          * now we've found our entries, pull them out of the free space
2456          * cache and put them into the cluster rbtree
2457          */
2458         do {
2459                 int ret;
2460
2461                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2462                 node = rb_next(&entry->offset_index);
2463                 if (entry->bitmap || entry->bytes < min_bytes)
2464                         continue;
2465
2466                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2467                 ret = tree_insert_offset(&cluster->root, entry->offset,
2468                                          &entry->offset_index, 0);
2469                 total_size += entry->bytes;
2470                 BUG_ON(ret); /* -EEXIST; Logic error */
2471         } while (node && entry != last);
2472
2473         cluster->max_size = max_extent;
2474         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2475         return 0;
2476 }
2477
2478 /*
2479  * This specifically looks for bitmaps that may work in the cluster, we assume
2480  * that we have already failed to find extents that will work.
2481  */
2482 static noinline int
2483 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2484                      struct btrfs_free_cluster *cluster,
2485                      struct list_head *bitmaps, u64 offset, u64 bytes,
2486                      u64 cont1_bytes, u64 min_bytes)
2487 {
2488         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2489         struct btrfs_free_space *entry;
2490         int ret = -ENOSPC;
2491         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2492
2493         if (ctl->total_bitmaps == 0)
2494                 return -ENOSPC;
2495
2496         /*
2497          * The bitmap that covers offset won't be in the list unless offset
2498          * is just its start offset.
2499          */
2500         entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2501         if (entry->offset != bitmap_offset) {
2502                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2503                 if (entry && list_empty(&entry->list))
2504                         list_add(&entry->list, bitmaps);
2505         }
2506
2507         list_for_each_entry(entry, bitmaps, list) {
2508                 if (entry->bytes < bytes)
2509                         continue;
2510                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2511                                            bytes, cont1_bytes, min_bytes);
2512                 if (!ret)
2513                         return 0;
2514         }
2515
2516         /*
2517          * The bitmaps list has all the bitmaps that record free space
2518          * starting after offset, so no more search is required.
2519          */
2520         return -ENOSPC;
2521 }
2522
2523 /*
2524  * here we try to find a cluster of blocks in a block group.  The goal
2525  * is to find at least bytes+empty_size.
2526  * We might not find them all in one contiguous area.
2527  *
2528  * returns zero and sets up cluster if things worked out, otherwise
2529  * it returns -enospc
2530  */
2531 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2532                              struct btrfs_root *root,
2533                              struct btrfs_block_group_cache *block_group,
2534                              struct btrfs_free_cluster *cluster,
2535                              u64 offset, u64 bytes, u64 empty_size)
2536 {
2537         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2538         struct btrfs_free_space *entry, *tmp;
2539         LIST_HEAD(bitmaps);
2540         u64 min_bytes;
2541         u64 cont1_bytes;
2542         int ret;
2543
2544         /*
2545          * Choose the minimum extent size we'll require for this
2546          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2547          * For metadata, allow allocates with smaller extents.  For
2548          * data, keep it dense.
2549          */
2550         if (btrfs_test_opt(root, SSD_SPREAD)) {
2551                 cont1_bytes = min_bytes = bytes + empty_size;
2552         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2553                 cont1_bytes = bytes;
2554                 min_bytes = block_group->sectorsize;
2555         } else {
2556                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2557                 min_bytes = block_group->sectorsize;
2558         }
2559
2560         spin_lock(&ctl->tree_lock);
2561
2562         /*
2563          * If we know we don't have enough space to make a cluster don't even
2564          * bother doing all the work to try and find one.
2565          */
2566         if (ctl->free_space < bytes) {
2567                 spin_unlock(&ctl->tree_lock);
2568                 return -ENOSPC;
2569         }
2570
2571         spin_lock(&cluster->lock);
2572
2573         /* someone already found a cluster, hooray */
2574         if (cluster->block_group) {
2575                 ret = 0;
2576                 goto out;
2577         }
2578
2579         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2580                                  min_bytes);
2581
2582         INIT_LIST_HEAD(&bitmaps);
2583         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2584                                       bytes + empty_size,
2585                                       cont1_bytes, min_bytes);
2586         if (ret)
2587                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2588                                            offset, bytes + empty_size,
2589                                            cont1_bytes, min_bytes);
2590
2591         /* Clear our temporary list */
2592         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2593                 list_del_init(&entry->list);
2594
2595         if (!ret) {
2596                 atomic_inc(&block_group->count);
2597                 list_add_tail(&cluster->block_group_list,
2598                               &block_group->cluster_list);
2599                 cluster->block_group = block_group;
2600         } else {
2601                 trace_btrfs_failed_cluster_setup(block_group);
2602         }
2603 out:
2604         spin_unlock(&cluster->lock);
2605         spin_unlock(&ctl->tree_lock);
2606
2607         return ret;
2608 }
2609
2610 /*
2611  * simple code to zero out a cluster
2612  */
2613 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2614 {
2615         spin_lock_init(&cluster->lock);
2616         spin_lock_init(&cluster->refill_lock);
2617         cluster->root = RB_ROOT;
2618         cluster->max_size = 0;
2619         INIT_LIST_HEAD(&cluster->block_group_list);
2620         cluster->block_group = NULL;
2621 }
2622
2623 static int do_trimming(struct btrfs_block_group_cache *block_group,
2624                        u64 *total_trimmed, u64 start, u64 bytes,
2625                        u64 reserved_start, u64 reserved_bytes)
2626 {
2627         struct btrfs_space_info *space_info = block_group->space_info;
2628         struct btrfs_fs_info *fs_info = block_group->fs_info;
2629         int ret;
2630         int update = 0;
2631         u64 trimmed = 0;
2632
2633         spin_lock(&space_info->lock);
2634         spin_lock(&block_group->lock);
2635         if (!block_group->ro) {
2636                 block_group->reserved += reserved_bytes;
2637                 space_info->bytes_reserved += reserved_bytes;
2638                 update = 1;
2639         }
2640         spin_unlock(&block_group->lock);
2641         spin_unlock(&space_info->lock);
2642
2643         ret = btrfs_error_discard_extent(fs_info->extent_root,
2644                                          start, bytes, &trimmed);
2645         if (!ret)
2646                 *total_trimmed += trimmed;
2647
2648         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2649
2650         if (update) {
2651                 spin_lock(&space_info->lock);
2652                 spin_lock(&block_group->lock);
2653                 if (block_group->ro)
2654                         space_info->bytes_readonly += reserved_bytes;
2655                 block_group->reserved -= reserved_bytes;
2656                 space_info->bytes_reserved -= reserved_bytes;
2657                 spin_unlock(&space_info->lock);
2658                 spin_unlock(&block_group->lock);
2659         }
2660
2661         return ret;
2662 }
2663
2664 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2665                           u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2666 {
2667         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2668         struct btrfs_free_space *entry;
2669         struct rb_node *node;
2670         int ret = 0;
2671         u64 extent_start;
2672         u64 extent_bytes;
2673         u64 bytes;
2674
2675         while (start < end) {
2676                 spin_lock(&ctl->tree_lock);
2677
2678                 if (ctl->free_space < minlen) {
2679                         spin_unlock(&ctl->tree_lock);
2680                         break;
2681                 }
2682
2683                 entry = tree_search_offset(ctl, start, 0, 1);
2684                 if (!entry) {
2685                         spin_unlock(&ctl->tree_lock);
2686                         break;
2687                 }
2688
2689                 /* skip bitmaps */
2690                 while (entry->bitmap) {
2691                         node = rb_next(&entry->offset_index);
2692                         if (!node) {
2693                                 spin_unlock(&ctl->tree_lock);
2694                                 goto out;
2695                         }
2696                         entry = rb_entry(node, struct btrfs_free_space,
2697                                          offset_index);
2698                 }
2699
2700                 if (entry->offset >= end) {
2701                         spin_unlock(&ctl->tree_lock);
2702                         break;
2703                 }
2704
2705                 extent_start = entry->offset;
2706                 extent_bytes = entry->bytes;
2707                 start = max(start, extent_start);
2708                 bytes = min(extent_start + extent_bytes, end) - start;
2709                 if (bytes < minlen) {
2710                         spin_unlock(&ctl->tree_lock);
2711                         goto next;
2712                 }
2713
2714                 unlink_free_space(ctl, entry);
2715                 kmem_cache_free(btrfs_free_space_cachep, entry);
2716
2717                 spin_unlock(&ctl->tree_lock);
2718
2719                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2720                                   extent_start, extent_bytes);
2721                 if (ret)
2722                         break;
2723 next:
2724                 start += bytes;
2725
2726                 if (fatal_signal_pending(current)) {
2727                         ret = -ERESTARTSYS;
2728                         break;
2729                 }
2730
2731                 cond_resched();
2732         }
2733 out:
2734         return ret;
2735 }
2736
2737 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2738                         u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2739 {
2740         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2741         struct btrfs_free_space *entry;
2742         int ret = 0;
2743         int ret2;
2744         u64 bytes;
2745         u64 offset = offset_to_bitmap(ctl, start);
2746
2747         while (offset < end) {
2748                 bool next_bitmap = false;
2749
2750                 spin_lock(&ctl->tree_lock);
2751
2752                 if (ctl->free_space < minlen) {
2753                         spin_unlock(&ctl->tree_lock);
2754                         break;
2755                 }
2756
2757                 entry = tree_search_offset(ctl, offset, 1, 0);
2758                 if (!entry) {
2759                         spin_unlock(&ctl->tree_lock);
2760                         next_bitmap = true;
2761                         goto next;
2762                 }
2763
2764                 bytes = minlen;
2765                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2766                 if (ret2 || start >= end) {
2767                         spin_unlock(&ctl->tree_lock);
2768                         next_bitmap = true;
2769                         goto next;
2770                 }
2771
2772                 bytes = min(bytes, end - start);
2773                 if (bytes < minlen) {
2774                         spin_unlock(&ctl->tree_lock);
2775                         goto next;
2776                 }
2777
2778                 bitmap_clear_bits(ctl, entry, start, bytes);
2779                 if (entry->bytes == 0)
2780                         free_bitmap(ctl, entry);
2781
2782                 spin_unlock(&ctl->tree_lock);
2783
2784                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2785                                   start, bytes);
2786                 if (ret)
2787                         break;
2788 next:
2789                 if (next_bitmap) {
2790                         offset += BITS_PER_BITMAP * ctl->unit;
2791                 } else {
2792                         start += bytes;
2793                         if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2794                                 offset += BITS_PER_BITMAP * ctl->unit;
2795                 }
2796
2797                 if (fatal_signal_pending(current)) {
2798                         ret = -ERESTARTSYS;
2799                         break;
2800                 }
2801
2802                 cond_resched();
2803         }
2804
2805         return ret;
2806 }
2807
2808 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2809                            u64 *trimmed, u64 start, u64 end, u64 minlen)
2810 {
2811         int ret;
2812
2813         *trimmed = 0;
2814
2815         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2816         if (ret)
2817                 return ret;
2818
2819         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2820
2821         return ret;
2822 }
2823
2824 /*
2825  * Find the left-most item in the cache tree, and then return the
2826  * smallest inode number in the item.
2827  *
2828  * Note: the returned inode number may not be the smallest one in
2829  * the tree, if the left-most item is a bitmap.
2830  */
2831 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2832 {
2833         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2834         struct btrfs_free_space *entry = NULL;
2835         u64 ino = 0;
2836
2837         spin_lock(&ctl->tree_lock);
2838
2839         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2840                 goto out;
2841
2842         entry = rb_entry(rb_first(&ctl->free_space_offset),
2843                          struct btrfs_free_space, offset_index);
2844
2845         if (!entry->bitmap) {
2846                 ino = entry->offset;
2847
2848                 unlink_free_space(ctl, entry);
2849                 entry->offset++;
2850                 entry->bytes--;
2851                 if (!entry->bytes)
2852                         kmem_cache_free(btrfs_free_space_cachep, entry);
2853                 else
2854                         link_free_space(ctl, entry);
2855         } else {
2856                 u64 offset = 0;
2857                 u64 count = 1;
2858                 int ret;
2859
2860                 ret = search_bitmap(ctl, entry, &offset, &count);
2861                 /* Logic error; Should be empty if it can't find anything */
2862                 BUG_ON(ret);
2863
2864                 ino = offset;
2865                 bitmap_clear_bits(ctl, entry, offset, 1);
2866                 if (entry->bytes == 0)
2867                         free_bitmap(ctl, entry);
2868         }
2869 out:
2870         spin_unlock(&ctl->tree_lock);
2871
2872         return ino;
2873 }
2874
2875 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2876                                     struct btrfs_path *path)
2877 {
2878         struct inode *inode = NULL;
2879
2880         spin_lock(&root->cache_lock);
2881         if (root->cache_inode)
2882                 inode = igrab(root->cache_inode);
2883         spin_unlock(&root->cache_lock);
2884         if (inode)
2885                 return inode;
2886
2887         inode = __lookup_free_space_inode(root, path, 0);
2888         if (IS_ERR(inode))
2889                 return inode;
2890
2891         spin_lock(&root->cache_lock);
2892         if (!btrfs_fs_closing(root->fs_info))
2893                 root->cache_inode = igrab(inode);
2894         spin_unlock(&root->cache_lock);
2895
2896         return inode;
2897 }
2898
2899 int create_free_ino_inode(struct btrfs_root *root,
2900                           struct btrfs_trans_handle *trans,
2901                           struct btrfs_path *path)
2902 {
2903         return __create_free_space_inode(root, trans, path,
2904                                          BTRFS_FREE_INO_OBJECTID, 0);
2905 }
2906
2907 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2908 {
2909         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2910         struct btrfs_path *path;
2911         struct inode *inode;
2912         int ret = 0;
2913         u64 root_gen = btrfs_root_generation(&root->root_item);
2914
2915         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2916                 return 0;
2917
2918         /*
2919          * If we're unmounting then just return, since this does a search on the
2920          * normal root and not the commit root and we could deadlock.
2921          */
2922         if (btrfs_fs_closing(fs_info))
2923                 return 0;
2924
2925         path = btrfs_alloc_path();
2926         if (!path)
2927                 return 0;
2928
2929         inode = lookup_free_ino_inode(root, path);
2930         if (IS_ERR(inode))
2931                 goto out;
2932
2933         if (root_gen != BTRFS_I(inode)->generation)
2934                 goto out_put;
2935
2936         ret = __load_free_space_cache(root, inode, ctl, path, 0);
2937
2938         if (ret < 0)
2939                 btrfs_err(fs_info,
2940                         "failed to load free ino cache for root %llu",
2941                         root->root_key.objectid);
2942 out_put:
2943         iput(inode);
2944 out:
2945         btrfs_free_path(path);
2946         return ret;
2947 }
2948
2949 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2950                               struct btrfs_trans_handle *trans,
2951                               struct btrfs_path *path)
2952 {
2953         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2954         struct inode *inode;
2955         int ret;
2956
2957         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2958                 return 0;
2959
2960         inode = lookup_free_ino_inode(root, path);
2961         if (IS_ERR(inode))
2962                 return 0;
2963
2964         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2965         if (ret) {
2966                 btrfs_delalloc_release_metadata(inode, inode->i_size);
2967 #ifdef DEBUG
2968                 btrfs_err(root->fs_info,
2969                         "failed to write free ino cache for root %llu",
2970                         root->root_key.objectid);
2971 #endif
2972         }
2973
2974         iput(inode);
2975         return ret;
2976 }
2977
2978 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
2979 static struct btrfs_block_group_cache *init_test_block_group(void)
2980 {
2981         struct btrfs_block_group_cache *cache;
2982
2983         cache = kzalloc(sizeof(*cache), GFP_NOFS);
2984         if (!cache)
2985                 return NULL;
2986         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
2987                                         GFP_NOFS);
2988         if (!cache->free_space_ctl) {
2989                 kfree(cache);
2990                 return NULL;
2991         }
2992
2993         cache->key.objectid = 0;
2994         cache->key.offset = 1024 * 1024 * 1024;
2995         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2996         cache->sectorsize = 4096;
2997
2998         spin_lock_init(&cache->lock);
2999         INIT_LIST_HEAD(&cache->list);
3000         INIT_LIST_HEAD(&cache->cluster_list);
3001         INIT_LIST_HEAD(&cache->new_bg_list);
3002
3003         btrfs_init_free_space_ctl(cache);
3004
3005         return cache;
3006 }
3007
3008 /*
3009  * Checks to see if the given range is in the free space cache.  This is really
3010  * just used to check the absence of space, so if there is free space in the
3011  * range at all we will return 1.
3012  */
3013 static int check_exists(struct btrfs_block_group_cache *cache, u64 offset,
3014                         u64 bytes)
3015 {
3016         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3017         struct btrfs_free_space *info;
3018         int ret = 0;
3019
3020         spin_lock(&ctl->tree_lock);
3021         info = tree_search_offset(ctl, offset, 0, 0);
3022         if (!info) {
3023                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3024                                           1, 0);
3025                 if (!info)
3026                         goto out;
3027         }
3028
3029 have_info:
3030         if (info->bitmap) {
3031                 u64 bit_off, bit_bytes;
3032                 struct rb_node *n;
3033                 struct btrfs_free_space *tmp;
3034
3035                 bit_off = offset;
3036                 bit_bytes = ctl->unit;
3037                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3038                 if (!ret) {
3039                         if (bit_off == offset) {
3040                                 ret = 1;
3041                                 goto out;
3042                         } else if (bit_off > offset &&
3043                                    offset + bytes > bit_off) {
3044                                 ret = 1;
3045                                 goto out;
3046                         }
3047                 }
3048
3049                 n = rb_prev(&info->offset_index);
3050                 while (n) {
3051                         tmp = rb_entry(n, struct btrfs_free_space,
3052                                        offset_index);
3053                         if (tmp->offset + tmp->bytes < offset)
3054                                 break;
3055                         if (offset + bytes < tmp->offset) {
3056                                 n = rb_prev(&info->offset_index);
3057                                 continue;
3058                         }
3059                         info = tmp;
3060                         goto have_info;
3061                 }
3062
3063                 n = rb_next(&info->offset_index);
3064                 while (n) {
3065                         tmp = rb_entry(n, struct btrfs_free_space,
3066                                        offset_index);
3067                         if (offset + bytes < tmp->offset)
3068                                 break;
3069                         if (tmp->offset + tmp->bytes < offset) {
3070                                 n = rb_next(&info->offset_index);
3071                                 continue;
3072                         }
3073                         info = tmp;
3074                         goto have_info;
3075                 }
3076
3077                 goto out;
3078         }
3079
3080         if (info->offset == offset) {
3081                 ret = 1;
3082                 goto out;
3083         }
3084
3085         if (offset > info->offset && offset < info->offset + info->bytes)
3086                 ret = 1;
3087 out:
3088         spin_unlock(&ctl->tree_lock);
3089         return ret;
3090 }
3091
3092 /*
3093  * Use this if you need to make a bitmap or extent entry specifically, it
3094  * doesn't do any of the merging that add_free_space does, this acts a lot like
3095  * how the free space cache loading stuff works, so you can get really weird
3096  * configurations.
3097  */
3098 static int add_free_space_entry(struct btrfs_block_group_cache *cache,
3099                                 u64 offset, u64 bytes, bool bitmap)
3100 {
3101         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3102         struct btrfs_free_space *info = NULL, *bitmap_info;
3103         void *map = NULL;
3104         u64 bytes_added;
3105         int ret;
3106
3107 again:
3108         if (!info) {
3109                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3110                 if (!info)
3111                         return -ENOMEM;
3112         }
3113
3114         if (!bitmap) {
3115                 spin_lock(&ctl->tree_lock);
3116                 info->offset = offset;
3117                 info->bytes = bytes;
3118                 ret = link_free_space(ctl, info);
3119                 spin_unlock(&ctl->tree_lock);
3120                 if (ret)
3121                         kmem_cache_free(btrfs_free_space_cachep, info);
3122                 return ret;
3123         }
3124
3125         if (!map) {
3126                 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3127                 if (!map) {
3128                         kmem_cache_free(btrfs_free_space_cachep, info);
3129                         return -ENOMEM;
3130                 }
3131         }
3132
3133         spin_lock(&ctl->tree_lock);
3134         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3135                                          1, 0);
3136         if (!bitmap_info) {
3137                 info->bitmap = map;
3138                 map = NULL;
3139                 add_new_bitmap(ctl, info, offset);
3140                 bitmap_info = info;
3141         }
3142
3143         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3144         bytes -= bytes_added;
3145         offset += bytes_added;
3146         spin_unlock(&ctl->tree_lock);
3147
3148         if (bytes)
3149                 goto again;
3150
3151         if (map)
3152                 kfree(map);
3153         return 0;
3154 }
3155
3156 /*
3157  * This test just does basic sanity checking, making sure we can add an exten
3158  * entry and remove space from either end and the middle, and make sure we can
3159  * remove space that covers adjacent extent entries.
3160  */
3161 static int test_extents(struct btrfs_block_group_cache *cache)
3162 {
3163         int ret = 0;
3164
3165         printk(KERN_ERR "Running extent only tests\n");
3166
3167         /* First just make sure we can remove an entire entry */
3168         ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
3169         if (ret) {
3170                 printk(KERN_ERR "Error adding initial extents %d\n", ret);
3171                 return ret;
3172         }
3173
3174         ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
3175         if (ret) {
3176                 printk(KERN_ERR "Error removing extent %d\n", ret);
3177                 return ret;
3178         }
3179
3180         if (check_exists(cache, 0, 4 * 1024 * 1024)) {
3181                 printk(KERN_ERR "Full remove left some lingering space\n");
3182                 return -1;
3183         }
3184
3185         /* Ok edge and middle cases now */
3186         ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
3187         if (ret) {
3188                 printk(KERN_ERR "Error adding half extent %d\n", ret);
3189                 return ret;
3190         }
3191
3192         ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 1 * 1024 * 1024);
3193         if (ret) {
3194                 printk(KERN_ERR "Error removing tail end %d\n", ret);
3195                 return ret;
3196         }
3197
3198         ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
3199         if (ret) {
3200                 printk(KERN_ERR "Error removing front end %d\n", ret);
3201                 return ret;
3202         }
3203
3204         ret = btrfs_remove_free_space(cache, 2 * 1024 * 1024, 4096);
3205         if (ret) {
3206                 printk(KERN_ERR "Error removing middle peice %d\n", ret);
3207                 return ret;
3208         }
3209
3210         if (check_exists(cache, 0, 1 * 1024 * 1024)) {
3211                 printk(KERN_ERR "Still have space at the front\n");
3212                 return -1;
3213         }
3214
3215         if (check_exists(cache, 2 * 1024 * 1024, 4096)) {
3216                 printk(KERN_ERR "Still have space in the middle\n");
3217                 return -1;
3218         }
3219
3220         if (check_exists(cache, 3 * 1024 * 1024, 1 * 1024 * 1024)) {
3221                 printk(KERN_ERR "Still have space at the end\n");
3222                 return -1;
3223         }
3224
3225         /* Cleanup */
3226         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3227
3228         return 0;
3229 }
3230
3231 static int test_bitmaps(struct btrfs_block_group_cache *cache)
3232 {
3233         u64 next_bitmap_offset;
3234         int ret;
3235
3236         printk(KERN_ERR "Running bitmap only tests\n");
3237
3238         ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
3239         if (ret) {
3240                 printk(KERN_ERR "Couldn't create a bitmap entry %d\n", ret);
3241                 return ret;
3242         }
3243
3244         ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
3245         if (ret) {
3246                 printk(KERN_ERR "Error removing bitmap full range %d\n", ret);
3247                 return ret;
3248         }
3249
3250         if (check_exists(cache, 0, 4 * 1024 * 1024)) {
3251                 printk(KERN_ERR "Left some space in bitmap\n");
3252                 return -1;
3253         }
3254
3255         ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
3256         if (ret) {
3257                 printk(KERN_ERR "Couldn't add to our bitmap entry %d\n", ret);
3258                 return ret;
3259         }
3260
3261         ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 2 * 1024 * 1024);
3262         if (ret) {
3263                 printk(KERN_ERR "Couldn't remove middle chunk %d\n", ret);
3264                 return ret;
3265         }
3266
3267         /*
3268          * The first bitmap we have starts at offset 0 so the next one is just
3269          * at the end of the first bitmap.
3270          */
3271         next_bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
3272
3273         /* Test a bit straddling two bitmaps */
3274         ret = add_free_space_entry(cache, next_bitmap_offset -
3275                                    (2 * 1024 * 1024), 4 * 1024 * 1024, 1);
3276         if (ret) {
3277                 printk(KERN_ERR "Couldn't add space that straddles two bitmaps"
3278                        " %d\n", ret);
3279                 return ret;
3280         }
3281
3282         ret = btrfs_remove_free_space(cache, next_bitmap_offset -
3283                                       (1 * 1024 * 1024), 2 * 1024 * 1024);
3284         if (ret) {
3285                 printk(KERN_ERR "Couldn't remove overlapping space %d\n", ret);
3286                 return ret;
3287         }
3288
3289         if (check_exists(cache, next_bitmap_offset - (1 * 1024 * 1024),
3290                          2 * 1024 * 1024)) {
3291                 printk(KERN_ERR "Left some space when removing overlapping\n");
3292                 return -1;
3293         }
3294
3295         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3296
3297         return 0;
3298 }
3299
3300 /* This is the high grade jackassery */
3301 static int test_bitmaps_and_extents(struct btrfs_block_group_cache *cache)
3302 {
3303         u64 bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
3304         int ret;
3305
3306         printk(KERN_ERR "Running bitmap and extent tests\n");
3307
3308         /*
3309          * First let's do something simple, an extent at the same offset as the
3310          * bitmap, but the free space completely in the extent and then
3311          * completely in the bitmap.
3312          */
3313         ret = add_free_space_entry(cache, 4 * 1024 * 1024, 1 * 1024 * 1024, 1);
3314         if (ret) {
3315                 printk(KERN_ERR "Couldn't create bitmap entry %d\n", ret);
3316                 return ret;
3317         }
3318
3319         ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
3320         if (ret) {
3321                 printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
3322                 return ret;
3323         }
3324
3325         ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
3326         if (ret) {
3327                 printk(KERN_ERR "Couldn't remove extent entry %d\n", ret);
3328                 return ret;
3329         }
3330
3331         if (check_exists(cache, 0, 1 * 1024 * 1024)) {
3332                 printk(KERN_ERR "Left remnants after our remove\n");
3333                 return -1;
3334         }
3335
3336         /* Now to add back the extent entry and remove from the bitmap */
3337         ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
3338         if (ret) {
3339                 printk(KERN_ERR "Couldn't re-add extent entry %d\n", ret);
3340                 return ret;
3341         }
3342
3343         ret = btrfs_remove_free_space(cache, 4 * 1024 * 1024, 1 * 1024 * 1024);
3344         if (ret) {
3345                 printk(KERN_ERR "Couldn't remove from bitmap %d\n", ret);
3346                 return ret;
3347         }
3348
3349         if (check_exists(cache, 4 * 1024 * 1024, 1 * 1024 * 1024)) {
3350                 printk(KERN_ERR "Left remnants in the bitmap\n");
3351                 return -1;
3352         }
3353
3354         /*
3355          * Ok so a little more evil, extent entry and bitmap at the same offset,
3356          * removing an overlapping chunk.
3357          */
3358         ret = add_free_space_entry(cache, 1 * 1024 * 1024, 4 * 1024 * 1024, 1);
3359         if (ret) {
3360                 printk(KERN_ERR "Couldn't add to a bitmap %d\n", ret);
3361                 return ret;
3362         }
3363
3364         ret = btrfs_remove_free_space(cache, 512 * 1024, 3 * 1024 * 1024);
3365         if (ret) {
3366                 printk(KERN_ERR "Couldn't remove overlapping space %d\n", ret);
3367                 return ret;
3368         }
3369
3370         if (check_exists(cache, 512 * 1024, 3 * 1024 * 1024)) {
3371                 printk(KERN_ERR "Left over peices after removing "
3372                        "overlapping\n");
3373                 return -1;
3374         }
3375
3376         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3377
3378         /* Now with the extent entry offset into the bitmap */
3379         ret = add_free_space_entry(cache, 4 * 1024 * 1024, 4 * 1024 * 1024, 1);
3380         if (ret) {
3381                 printk(KERN_ERR "Couldn't add space to the bitmap %d\n", ret);
3382                 return ret;
3383         }
3384
3385         ret = add_free_space_entry(cache, 2 * 1024 * 1024, 2 * 1024 * 1024, 0);
3386         if (ret) {
3387                 printk(KERN_ERR "Couldn't add extent to the cache %d\n", ret);
3388                 return ret;
3389         }
3390
3391         ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 4 * 1024 * 1024);
3392         if (ret) {
3393                 printk(KERN_ERR "Problem removing overlapping space %d\n", ret);
3394                 return ret;
3395         }
3396
3397         if (check_exists(cache, 3 * 1024 * 1024, 4 * 1024 * 1024)) {
3398                 printk(KERN_ERR "Left something behind when removing space");
3399                 return -1;
3400         }
3401
3402         /*
3403          * This has blown up in the past, the extent entry starts before the
3404          * bitmap entry, but we're trying to remove an offset that falls
3405          * completely within the bitmap range and is in both the extent entry
3406          * and the bitmap entry, looks like this
3407          *
3408          *   [ extent ]
3409          *      [ bitmap ]
3410          *        [ del ]
3411          */
3412         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3413         ret = add_free_space_entry(cache, bitmap_offset + 4 * 1024 * 1024,
3414                                    4 * 1024 * 1024, 1);
3415         if (ret) {
3416                 printk(KERN_ERR "Couldn't add bitmap %d\n", ret);
3417                 return ret;
3418         }
3419
3420         ret = add_free_space_entry(cache, bitmap_offset - 1 * 1024 * 1024,
3421                                    5 * 1024 * 1024, 0);
3422         if (ret) {
3423                 printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
3424                 return ret;
3425         }
3426
3427         ret = btrfs_remove_free_space(cache, bitmap_offset + 1 * 1024 * 1024,
3428                                       5 * 1024 * 1024);
3429         if (ret) {
3430                 printk(KERN_ERR "Failed to free our space %d\n", ret);
3431                 return ret;
3432         }
3433
3434         if (check_exists(cache, bitmap_offset + 1 * 1024 * 1024,
3435                          5 * 1024 * 1024)) {
3436                 printk(KERN_ERR "Left stuff over\n");
3437                 return -1;
3438         }
3439
3440         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3441
3442         /*
3443          * This blew up before, we have part of the free space in a bitmap and
3444          * then the entirety of the rest of the space in an extent.  This used
3445          * to return -EAGAIN back from btrfs_remove_extent, make sure this
3446          * doesn't happen.
3447          */
3448         ret = add_free_space_entry(cache, 1 * 1024 * 1024, 2 * 1024 * 1024, 1);
3449         if (ret) {
3450                 printk(KERN_ERR "Couldn't add bitmap entry %d\n", ret);
3451                 return ret;
3452         }
3453
3454         ret = add_free_space_entry(cache, 3 * 1024 * 1024, 1 * 1024 * 1024, 0);
3455         if (ret) {
3456                 printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
3457                 return ret;
3458         }
3459
3460         ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 3 * 1024 * 1024);
3461         if (ret) {
3462                 printk(KERN_ERR "Error removing bitmap and extent "
3463                        "overlapping %d\n", ret);
3464                 return ret;
3465         }
3466
3467         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3468         return 0;
3469 }
3470
3471 void btrfs_test_free_space_cache(void)
3472 {
3473         struct btrfs_block_group_cache *cache;
3474
3475         printk(KERN_ERR "Running btrfs free space cache tests\n");
3476
3477         cache = init_test_block_group();
3478         if (!cache) {
3479                 printk(KERN_ERR "Couldn't run the tests\n");
3480                 return;
3481         }
3482
3483         if (test_extents(cache))
3484                 goto out;
3485         if (test_bitmaps(cache))
3486                 goto out;
3487         if (test_bitmaps_and_extents(cache))
3488                 goto out;
3489 out:
3490         __btrfs_remove_free_space_cache(cache->free_space_ctl);
3491         kfree(cache->free_space_ctl);
3492         kfree(cache);
3493         printk(KERN_ERR "Free space cache tests finished\n");
3494 }
3495 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */