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