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 "ctree.h"
  24 #include "free-space-cache.h"
  25 #include "transaction.h"
  26 #include "disk-io.h"
  27 #include "extent_io.h"
  28 #include "inode-map.h"
  29
  30 #define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
  31 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
  32
  33 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  34                            struct btrfs_free_space *info);
  35
  36 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  37                                                struct btrfs_path *path,
  38                                                u64 offset)
  39 {
  40         struct btrfs_key key;
  41         struct btrfs_key location;
  42         struct btrfs_disk_key disk_key;
  43         struct btrfs_free_space_header *header;
  44         struct extent_buffer *leaf;
  45         struct inode *inode = NULL;
  46         int ret;
  47
  48         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  49         key.offset = offset;
  50         key.type = 0;
  51
  52         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  53         if (ret < 0)
  54                 return ERR_PTR(ret);
  55         if (ret > 0) {
  56                 btrfs_release_path(path);
  57                 return ERR_PTR(-ENOENT);
  58         }
  59
  60         leaf = path->nodes[0];
  61         header = btrfs_item_ptr(leaf, path->slots[0],
  62                                 struct btrfs_free_space_header);
  63         btrfs_free_space_key(leaf, header, &disk_key);
  64         btrfs_disk_key_to_cpu(&location, &disk_key);
  65         btrfs_release_path(path);
  66
  67         inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
  68         if (!inode)
  69                 return ERR_PTR(-ENOENT);
  70         if (IS_ERR(inode))
  71                 return inode;
  72         if (is_bad_inode(inode)) {
  73                 iput(inode);
  74                 return ERR_PTR(-ENOENT);
  75         }
  76
  77         inode->i_mapping->flags &= ~__GFP_FS;
  78
  79         return inode;
  80 }
  81
  82 struct inode *lookup_free_space_inode(struct btrfs_root *root,
  83                                       struct btrfs_block_group_cache
  84                                       *block_group, struct btrfs_path *path)
  85 {
  86         struct inode *inode = NULL;
  87
  88         spin_lock(&block_group->lock);
  89         if (block_group->inode)
  90                 inode = igrab(block_group->inode);
  91         spin_unlock(&block_group->lock);
  92         if (inode)
  93                 return inode;
  94
  95         inode = __lookup_free_space_inode(root, path,
  96                                           block_group->key.objectid);
  97         if (IS_ERR(inode))
  98                 return inode;
  99
 100         spin_lock(&block_group->lock);
 101         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) {
 102                 printk(KERN_INFO "Old style space inode found, converting.\n");
 103                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NODATASUM;
 104                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 105         }
 106
 107         if (!btrfs_fs_closing(root->fs_info)) {
 108                 block_group->inode = igrab(inode);
 109                 block_group->iref = 1;
 110         }
 111         spin_unlock(&block_group->lock);
 112
 113         return inode;
 114 }
 115
 116 int __create_free_space_inode(struct btrfs_root *root,
 117                               struct btrfs_trans_handle *trans,
 118                               struct btrfs_path *path, u64 ino, u64 offset)
 119 {
 120         struct btrfs_key key;
 121         struct btrfs_disk_key disk_key;
 122         struct btrfs_free_space_header *header;
 123         struct btrfs_inode_item *inode_item;
 124         struct extent_buffer *leaf;
 125         int ret;
 126
 127         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 128         if (ret)
 129                 return ret;
 130
 131         leaf = path->nodes[0];
 132         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 133                                     struct btrfs_inode_item);
 134         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 135         memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
 136                              sizeof(*inode_item));
 137         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 138         btrfs_set_inode_size(leaf, inode_item, 0);
 139         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 140         btrfs_set_inode_uid(leaf, inode_item, 0);
 141         btrfs_set_inode_gid(leaf, inode_item, 0);
 142         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 143         btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS |
 144                               BTRFS_INODE_PREALLOC);
 145         btrfs_set_inode_nlink(leaf, inode_item, 1);
 146         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 147         btrfs_set_inode_block_group(leaf, inode_item, offset);
 148         btrfs_mark_buffer_dirty(leaf);
 149         btrfs_release_path(path);
 150
 151         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 152         key.offset = offset;
 153         key.type = 0;
 154
 155         ret = btrfs_insert_empty_item(trans, root, path, &key,
 156                                       sizeof(struct btrfs_free_space_header));
 157         if (ret < 0) {
 158                 btrfs_release_path(path);
 159                 return ret;
 160         }
 161         leaf = path->nodes[0];
 162         header = btrfs_item_ptr(leaf, path->slots[0],
 163                                 struct btrfs_free_space_header);
 164         memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
 165         btrfs_set_free_space_key(leaf, header, &disk_key);
 166         btrfs_mark_buffer_dirty(leaf);
 167         btrfs_release_path(path);
 168
 169         return 0;
 170 }
 171
 172 int create_free_space_inode(struct btrfs_root *root,
 173                             struct btrfs_trans_handle *trans,
 174                             struct btrfs_block_group_cache *block_group,
 175                             struct btrfs_path *path)
 176 {
 177         int ret;
 178         u64 ino;
 179
 180         ret = btrfs_find_free_objectid(root, &ino);
 181         if (ret < 0)
 182                 return ret;
 183
 184         return __create_free_space_inode(root, trans, path, ino,
 185                                          block_group->key.objectid);
 186 }
 187
 188 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
 189                                     struct btrfs_trans_handle *trans,
 190                                     struct btrfs_path *path,
 191                                     struct inode *inode)
 192 {
 193         loff_t oldsize;
 194         int ret = 0;
 195
 196         trans->block_rsv = root->orphan_block_rsv;
 197         ret = btrfs_block_rsv_check(trans, root,
 198                                     root->orphan_block_rsv,
 199                                     0, 5);
 200         if (ret)
 201                 return ret;
 202
 203         oldsize = i_size_read(inode);
 204         btrfs_i_size_write(inode, 0);
 205         truncate_pagecache(inode, oldsize, 0);
 206
 207         /*
 208          * We don't need an orphan item because truncating the free space cache
 209          * will never be split across transactions.
 210          */
 211         ret = btrfs_truncate_inode_items(trans, root, inode,
 212                                          0, BTRFS_EXTENT_DATA_KEY);
 213         if (ret) {
 214                 WARN_ON(1);
 215                 return ret;
 216         }
 217
 218         ret = btrfs_update_inode(trans, root, inode);
 219         return ret;
 220 }
 221
 222 static int readahead_cache(struct inode *inode)
 223 {
 224         struct file_ra_state *ra;
 225         unsigned long last_index;
 226
 227         ra = kzalloc(sizeof(*ra), GFP_NOFS);
 228         if (!ra)
 229                 return -ENOMEM;
 230
 231         file_ra_state_init(ra, inode->i_mapping);
 232         last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
 233
 234         page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 235
 236         kfree(ra);
 237
 238         return 0;
 239 }
 240
 241 int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 242                             struct btrfs_free_space_ctl *ctl,
 243                             struct btrfs_path *path, u64 offset)
 244 {
 245         struct btrfs_free_space_header *header;
 246         struct extent_buffer *leaf;
 247         struct page *page;
 248         struct btrfs_key key;
 249         struct list_head bitmaps;
 250         u64 num_entries;
 251         u64 num_bitmaps;
 252         u64 generation;
 253         pgoff_t index = 0;
 254         int ret = 0;
 255
 256         INIT_LIST_HEAD(&bitmaps);
 257
 258         /* Nothing in the space cache, goodbye */
 259         if (!i_size_read(inode))
 260                 goto out;
 261
 262         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 263         key.offset = offset;
 264         key.type = 0;
 265
 266         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 267         if (ret < 0)
 268                 goto out;
 269         else if (ret > 0) {
 270                 btrfs_release_path(path);
 271                 ret = 0;
 272                 goto out;
 273         }
 274
 275         ret = -1;
 276
 277         leaf = path->nodes[0];
 278         header = btrfs_item_ptr(leaf, path->slots[0],
 279                                 struct btrfs_free_space_header);
 280         num_entries = btrfs_free_space_entries(leaf, header);
 281         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 282         generation = btrfs_free_space_generation(leaf, header);
 283         btrfs_release_path(path);
 284
 285         if (BTRFS_I(inode)->generation != generation) {
 286                 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
 287                        " not match free space cache generation (%llu)\n",
 288                        (unsigned long long)BTRFS_I(inode)->generation,
 289                        (unsigned long long)generation);
 290                 goto out;
 291         }
 292
 293         if (!num_entries)
 294                 goto out;
 295
 296         ret = readahead_cache(inode);
 297         if (ret)
 298                 goto out;
 299
 300         while (1) {
 301                 struct btrfs_free_space_entry *entry;
 302                 struct btrfs_free_space *e;
 303                 void *addr;
 304                 unsigned long offset = 0;
 305                 int need_loop = 0;
 306
 307                 if (!num_entries && !num_bitmaps)
 308                         break;
 309
 310                 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
 311                 if (!page)
 312                         goto free_cache;
 313
 314                 if (!PageUptodate(page)) {
 315                         btrfs_readpage(NULL, page);
 316                         lock_page(page);
 317                         if (!PageUptodate(page)) {
 318                                 unlock_page(page);
 319                                 page_cache_release(page);
 320                                 printk(KERN_ERR "btrfs: error reading free "
 321                                        "space cache\n");
 322                                 goto free_cache;
 323                         }
 324                 }
 325                 addr = kmap(page);
 326
 327                 if (index == 0) {
 328                         u64 *gen;
 329
 330                         /*
 331                          * We put a bogus crc in the front of the first page in
 332                          * case old kernels try to mount a fs with the new
 333                          * format to make sure they discard the cache.
 334                          */
 335                         addr += sizeof(u64);
 336                         offset += sizeof(u64);
 337
 338                         gen = addr;
 339                         if (*gen != BTRFS_I(inode)->generation) {
 340                                 printk(KERN_ERR "btrfs: space cache generation"
 341                                        " (%llu) does not match inode (%llu)\n",
 342                                        (unsigned long long)*gen,
 343                                        (unsigned long long)
 344                                        BTRFS_I(inode)->generation);
 345                                 kunmap(page);
 346                                 unlock_page(page);
 347                                 page_cache_release(page);
 348                                 goto free_cache;
 349                         }
 350                         addr += sizeof(u64);
 351                         offset += sizeof(u64);
 352                 }
 353                 entry = addr;
 354
 355                 while (1) {
 356                         if (!num_entries)
 357                                 break;
 358
 359                         need_loop = 1;
 360                         e = kmem_cache_zalloc(btrfs_free_space_cachep,
 361                                               GFP_NOFS);
 362                         if (!e) {
 363                                 kunmap(page);
 364                                 unlock_page(page);
 365                                 page_cache_release(page);
 366                                 goto free_cache;
 367                         }
 368
 369                         e->offset = le64_to_cpu(entry->offset);
 370                         e->bytes = le64_to_cpu(entry->bytes);
 371                         if (!e->bytes) {
 372                                 kunmap(page);
 373                                 kmem_cache_free(btrfs_free_space_cachep, e);
 374                                 unlock_page(page);
 375                                 page_cache_release(page);
 376                                 goto free_cache;
 377                         }
 378
 379                         if (entry->type == BTRFS_FREE_SPACE_EXTENT) {
 380                                 spin_lock(&ctl->tree_lock);
 381                                 ret = link_free_space(ctl, e);
 382                                 spin_unlock(&ctl->tree_lock);
 383                                 if (ret) {
 384                                         printk(KERN_ERR "Duplicate entries in "
 385                                                "free space cache, dumping\n");
 386                                         kunmap(page);
 387                                         unlock_page(page);
 388                                         page_cache_release(page);
 389                                         goto free_cache;
 390                                 }
 391                         } else {
 392                                 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 393                                 if (!e->bitmap) {
 394                                         kunmap(page);
 395                                         kmem_cache_free(
 396                                                 btrfs_free_space_cachep, e);
 397                                         unlock_page(page);
 398                                         page_cache_release(page);
 399                                         goto free_cache;
 400                                 }
 401                                 spin_lock(&ctl->tree_lock);
 402                                 ret = link_free_space(ctl, e);
 403                                 ctl->total_bitmaps++;
 404                                 ctl->op->recalc_thresholds(ctl);
 405                                 spin_unlock(&ctl->tree_lock);
 406                                 if (ret) {
 407                                         printk(KERN_ERR "Duplicate entries in "
 408                                                "free space cache, dumping\n");
 409                                         kunmap(page);
 410                                         unlock_page(page);
 411                                         page_cache_release(page);
 412                                         goto free_cache;
 413                                 }
 414                                 list_add_tail(&e->list, &bitmaps);
 415                         }
 416
 417                         num_entries--;
 418                         offset += sizeof(struct btrfs_free_space_entry);
 419                         if (offset + sizeof(struct btrfs_free_space_entry) >=
 420                             PAGE_CACHE_SIZE)
 421                                 break;
 422                         entry++;
 423                 }
 424
 425                 /*
 426                  * We read an entry out of this page, we need to move on to the
 427                  * next page.
 428                  */
 429                 if (need_loop) {
 430                         kunmap(page);
 431                         goto next;
 432                 }
 433
 434                 /*
 435                  * We add the bitmaps at the end of the entries in order that
 436                  * the bitmap entries are added to the cache.
 437                  */
 438                 e = list_entry(bitmaps.next, struct btrfs_free_space, list);
 439                 list_del_init(&e->list);
 440                 memcpy(e->bitmap, addr, PAGE_CACHE_SIZE);
 441                 kunmap(page);
 442                 num_bitmaps--;
 443 next:
 444                 unlock_page(page);
 445                 page_cache_release(page);
 446                 index++;
 447         }
 448
 449         ret = 1;
 450 out:
 451         return ret;
 452 free_cache:
 453         __btrfs_remove_free_space_cache(ctl);
 454         goto out;
 455 }
 456
 457 int load_free_space_cache(struct btrfs_fs_info *fs_info,
 458                           struct btrfs_block_group_cache *block_group)
 459 {
 460         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 461         struct btrfs_root *root = fs_info->tree_root;
 462         struct inode *inode;
 463         struct btrfs_path *path;
 464         int ret;
 465         bool matched;
 466         u64 used = btrfs_block_group_used(&block_group->item);
 467
 468         /*
 469          * If we're unmounting then just return, since this does a search on the
 470          * normal root and not the commit root and we could deadlock.
 471          */
 472         if (btrfs_fs_closing(fs_info))
 473                 return 0;
 474
 475         /*
 476          * If this block group has been marked to be cleared for one reason or
 477          * another then we can't trust the on disk cache, so just return.
 478          */
 479         spin_lock(&block_group->lock);
 480         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 481                 spin_unlock(&block_group->lock);
 482                 return 0;
 483         }
 484         spin_unlock(&block_group->lock);
 485
 486         path = btrfs_alloc_path();
 487         if (!path)
 488                 return 0;
 489
 490         inode = lookup_free_space_inode(root, block_group, path);
 491         if (IS_ERR(inode)) {
 492                 btrfs_free_path(path);
 493                 return 0;
 494         }
 495
 496         ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 497                                       path, block_group->key.objectid);
 498         btrfs_free_path(path);
 499         if (ret <= 0)
 500                 goto out;
 501
 502         spin_lock(&ctl->tree_lock);
 503         matched = (ctl->free_space == (block_group->key.offset - used -
 504                                        block_group->bytes_super));
 505         spin_unlock(&ctl->tree_lock);
 506
 507         if (!matched) {
 508                 __btrfs_remove_free_space_cache(ctl);
 509                 printk(KERN_ERR "block group %llu has an wrong amount of free "
 510                        "space\n", block_group->key.objectid);
 511                 ret = -1;
 512         }
 513 out:
 514         if (ret < 0) {
 515                 /* This cache is bogus, make sure it gets cleared */
 516                 spin_lock(&block_group->lock);
 517                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 518                 spin_unlock(&block_group->lock);
 519                 ret = 0;
 520
 521                 printk(KERN_ERR "btrfs: failed to load free space cache "
 522                        "for block group %llu\n", block_group->key.objectid);
 523         }
 524
 525         iput(inode);
 526         return ret;
 527 }
 528
 529 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 530                             struct btrfs_free_space_ctl *ctl,
 531                             struct btrfs_block_group_cache *block_group,
 532                             struct btrfs_trans_handle *trans,
 533                             struct btrfs_path *path, u64 offset)
 534 {
 535         struct btrfs_free_space_header *header;
 536         struct extent_buffer *leaf;
 537         struct rb_node *node;
 538         struct list_head *pos, *n;
 539         struct page **pages;
 540         struct page *page;
 541         struct extent_state *cached_state = NULL;
 542         struct btrfs_free_cluster *cluster = NULL;
 543         struct extent_io_tree *unpin = NULL;
 544         struct list_head bitmap_list;
 545         struct btrfs_key key;
 546         u64 start, end, len;
 547         u64 bytes = 0;
 548         u32 crc = ~(u32)0;
 549         int index = 0, num_pages = 0;
 550         int entries = 0;
 551         int bitmaps = 0;
 552         int ret = -1;
 553         bool next_page = false;
 554         bool out_of_space = false;
 555
 556         INIT_LIST_HEAD(&bitmap_list);
 557
 558         node = rb_first(&ctl->free_space_offset);
 559         if (!node)
 560                 return 0;
 561
 562         if (!i_size_read(inode))
 563                 return -1;
 564
 565         num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
 566                 PAGE_CACHE_SHIFT;
 567
 568         filemap_write_and_wait(inode->i_mapping);
 569         btrfs_wait_ordered_range(inode, inode->i_size &
 570                                  ~(root->sectorsize - 1), (u64)-1);
 571
 572         pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
 573         if (!pages)
 574                 return -1;
 575
 576         /* Get the cluster for this block_group if it exists */
 577         if (block_group && !list_empty(&block_group->cluster_list))
 578                 cluster = list_entry(block_group->cluster_list.next,
 579                                      struct btrfs_free_cluster,
 580                                      block_group_list);
 581
 582         /*
 583          * We shouldn't have switched the pinned extents yet so this is the
 584          * right one
 585          */
 586         unpin = root->fs_info->pinned_extents;
 587
 588         /*
 589          * Lock all pages first so we can lock the extent safely.
 590          *
 591          * NOTE: Because we hold the ref the entire time we're going to write to
 592          * the page find_get_page should never fail, so we don't do a check
 593          * after find_get_page at this point.  Just putting this here so people
 594          * know and don't freak out.
 595          */
 596         while (index < num_pages) {
 597                 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
 598                 if (!page) {
 599                         int i;
 600
 601                         for (i = 0; i < num_pages; i++) {
 602                                 unlock_page(pages[i]);
 603                                 page_cache_release(pages[i]);
 604                         }
 605                         goto out;
 606                 }
 607                 pages[index] = page;
 608                 index++;
 609         }
 610
 611         index = 0;
 612         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
 613                          0, &cached_state, GFP_NOFS);
 614
 615         /*
 616          * When searching for pinned extents, we need to start at our start
 617          * offset.
 618          */
 619         if (block_group)
 620                 start = block_group->key.objectid;
 621
 622         /* Write out the extent entries */
 623         do {
 624                 struct btrfs_free_space_entry *entry;
 625                 void *addr, *orig;
 626                 unsigned long offset = 0;
 627
 628                 next_page = false;
 629
 630                 if (index >= num_pages) {
 631                         out_of_space = true;
 632                         break;
 633                 }
 634
 635                 page = pages[index];
 636
 637                 orig = addr = kmap(page);
 638                 if (index == 0) {
 639                         u64 *gen;
 640
 641                         /*
 642                          * We're going to put in a bogus crc for this page to
 643                          * make sure that old kernels who aren't aware of this
 644                          * format will be sure to discard the cache.
 645                          */
 646                         addr += sizeof(u64);
 647                         offset += sizeof(u64);
 648
 649                         gen = addr;
 650                         *gen = trans->transid;
 651                         addr += sizeof(u64);
 652                         offset += sizeof(u64);
 653                 }
 654                 entry = addr;
 655
 656                 memset(addr, 0, PAGE_CACHE_SIZE - offset);
 657                 while (node && !next_page) {
 658                         struct btrfs_free_space *e;
 659
 660                         e = rb_entry(node, struct btrfs_free_space, offset_index);
 661                         entries++;
 662
 663                         entry->offset = cpu_to_le64(e->offset);
 664                         entry->bytes = cpu_to_le64(e->bytes);
 665                         if (e->bitmap) {
 666                                 entry->type = BTRFS_FREE_SPACE_BITMAP;
 667                                 list_add_tail(&e->list, &bitmap_list);
 668                                 bitmaps++;
 669                         } else {
 670                                 entry->type = BTRFS_FREE_SPACE_EXTENT;
 671                         }
 672                         node = rb_next(node);
 673                         if (!node && cluster) {
 674                                 node = rb_first(&cluster->root);
 675                                 cluster = NULL;
 676                         }
 677                         offset += sizeof(struct btrfs_free_space_entry);
 678                         if (offset + sizeof(struct btrfs_free_space_entry) >=
 679                             PAGE_CACHE_SIZE)
 680                                 next_page = true;
 681                         entry++;
 682                 }
 683
 684                 /*
 685                  * We want to add any pinned extents to our free space cache
 686                  * so we don't leak the space
 687                  */
 688                 while (block_group && !next_page &&
 689                        (start < block_group->key.objectid +
 690                         block_group->key.offset)) {
 691                         ret = find_first_extent_bit(unpin, start, &start, &end,
 692                                                     EXTENT_DIRTY);
 693                         if (ret) {
 694                                 ret = 0;
 695                                 break;
 696                         }
 697
 698                         /* This pinned extent is out of our range */
 699                         if (start >= block_group->key.objectid +
 700                             block_group->key.offset)
 701                                 break;
 702
 703                         len = block_group->key.objectid +
 704                                 block_group->key.offset - start;
 705                         len = min(len, end + 1 - start);
 706
 707                         entries++;
 708                         entry->offset = cpu_to_le64(start);
 709                         entry->bytes = cpu_to_le64(len);
 710                         entry->type = BTRFS_FREE_SPACE_EXTENT;
 711
 712                         start = end + 1;
 713                         offset += sizeof(struct btrfs_free_space_entry);
 714                         if (offset + sizeof(struct btrfs_free_space_entry) >=
 715                             PAGE_CACHE_SIZE)
 716                                 next_page = true;
 717                         entry++;
 718                 }
 719
 720                 /* Generate bogus crc value */
 721                 if (index == 0) {
 722                         u32 *tmp;
 723                         crc = btrfs_csum_data(root, orig + sizeof(u64), crc,
 724                                               PAGE_CACHE_SIZE - sizeof(u64));
 725                         btrfs_csum_final(crc, (char *)&crc);
 726                         crc++;
 727                         tmp = orig;
 728                         *tmp = crc;
 729                 }
 730
 731                 kunmap(page);
 732
 733                 bytes += PAGE_CACHE_SIZE;
 734
 735                 index++;
 736         } while (node || next_page);
 737
 738         /* Write out the bitmaps */
 739         list_for_each_safe(pos, n, &bitmap_list) {
 740                 void *addr;
 741                 struct btrfs_free_space *entry =
 742                         list_entry(pos, struct btrfs_free_space, list);
 743
 744                 if (index >= num_pages) {
 745                         out_of_space = true;
 746                         break;
 747                 }
 748                 page = pages[index];
 749
 750                 addr = kmap(page);
 751                 memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE);
 752                 kunmap(page);
 753                 bytes += PAGE_CACHE_SIZE;
 754
 755                 list_del_init(&entry->list);
 756                 index++;
 757         }
 758
 759         if (out_of_space) {
 760                 btrfs_drop_pages(pages, num_pages);
 761                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
 762                                      i_size_read(inode) - 1, &cached_state,
 763                                      GFP_NOFS);
 764                 ret = 0;
 765                 goto out;
 766         }
 767
 768         /* Zero out the rest of the pages just to make sure */
 769         while (index < num_pages) {
 770                 void *addr;
 771
 772                 page = pages[index];
 773                 addr = kmap(page);
 774                 memset(addr, 0, PAGE_CACHE_SIZE);
 775                 kunmap(page);
 776                 bytes += PAGE_CACHE_SIZE;
 777                 index++;
 778         }
 779
 780         ret = btrfs_dirty_pages(root, inode, pages, num_pages, 0,
 781                                             bytes, &cached_state);
 782         btrfs_drop_pages(pages, num_pages);
 783         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
 784                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
 785
 786         if (ret) {
 787                 ret = 0;
 788                 goto out;
 789         }
 790
 791         BTRFS_I(inode)->generation = trans->transid;
 792
 793         filemap_write_and_wait(inode->i_mapping);
 794
 795         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 796         key.offset = offset;
 797         key.type = 0;
 798
 799         ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
 800         if (ret < 0) {
 801                 ret = -1;
 802                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
 803                                  EXTENT_DIRTY | EXTENT_DELALLOC |
 804                                  EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS);
 805                 goto out;
 806         }
 807         leaf = path->nodes[0];
 808         if (ret > 0) {
 809                 struct btrfs_key found_key;
 810                 BUG_ON(!path->slots[0]);
 811                 path->slots[0]--;
 812                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 813                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
 814                     found_key.offset != offset) {
 815                         ret = -1;
 816                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
 817                                          EXTENT_DIRTY | EXTENT_DELALLOC |
 818                                          EXTENT_DO_ACCOUNTING, 0, 0, NULL,
 819                                          GFP_NOFS);
 820                         btrfs_release_path(path);
 821                         goto out;
 822                 }
 823         }
 824         header = btrfs_item_ptr(leaf, path->slots[0],
 825                                 struct btrfs_free_space_header);
 826         btrfs_set_free_space_entries(leaf, header, entries);
 827         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
 828         btrfs_set_free_space_generation(leaf, header, trans->transid);
 829         btrfs_mark_buffer_dirty(leaf);
 830         btrfs_release_path(path);
 831
 832         ret = 1;
 833
 834 out:
 835         kfree(pages);
 836         if (ret != 1) {
 837                 invalidate_inode_pages2_range(inode->i_mapping, 0, index);
 838                 BTRFS_I(inode)->generation = 0;
 839         }
 840         btrfs_update_inode(trans, root, inode);
 841         return ret;
 842 }
 843
 844 int btrfs_write_out_cache(struct btrfs_root *root,
 845                           struct btrfs_trans_handle *trans,
 846                           struct btrfs_block_group_cache *block_group,
 847                           struct btrfs_path *path)
 848 {
 849         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 850         struct inode *inode;
 851         int ret = 0;
 852
 853         root = root->fs_info->tree_root;
 854
 855         spin_lock(&block_group->lock);
 856         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
 857                 spin_unlock(&block_group->lock);
 858                 return 0;
 859         }
 860         spin_unlock(&block_group->lock);
 861
 862         inode = lookup_free_space_inode(root, block_group, path);
 863         if (IS_ERR(inode))
 864                 return 0;
 865
 866         ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
 867                                       path, block_group->key.objectid);
 868         if (ret < 0) {
 869                 spin_lock(&block_group->lock);
 870                 block_group->disk_cache_state = BTRFS_DC_ERROR;
 871                 spin_unlock(&block_group->lock);
 872                 ret = 0;
 873
 874                 printk(KERN_ERR "btrfs: failed to write free space cace "
 875                        "for block group %llu\n", block_group->key.objectid);
 876         }
 877
 878         iput(inode);
 879         return ret;
 880 }
 881
 882 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
 883                                           u64 offset)
 884 {
 885         BUG_ON(offset < bitmap_start);
 886         offset -= bitmap_start;
 887         return (unsigned long)(div_u64(offset, unit));
 888 }
 889
 890 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
 891 {
 892         return (unsigned long)(div_u64(bytes, unit));
 893 }
 894
 895 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
 896                                    u64 offset)
 897 {
 898         u64 bitmap_start;
 899         u64 bytes_per_bitmap;
 900
 901         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
 902         bitmap_start = offset - ctl->start;
 903         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
 904         bitmap_start *= bytes_per_bitmap;
 905         bitmap_start += ctl->start;
 906
 907         return bitmap_start;
 908 }
 909
 910 static int tree_insert_offset(struct rb_root *root, u64 offset,
 911                               struct rb_node *node, int bitmap)
 912 {
 913         struct rb_node **p = &root->rb_node;
 914         struct rb_node *parent = NULL;
 915         struct btrfs_free_space *info;
 916
 917         while (*p) {
 918                 parent = *p;
 919                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
 920
 921                 if (offset < info->offset) {
 922                         p = &(*p)->rb_left;
 923                 } else if (offset > info->offset) {
 924                         p = &(*p)->rb_right;
 925                 } else {
 926                         /*
 927                          * we could have a bitmap entry and an extent entry
 928                          * share the same offset.  If this is the case, we want
 929                          * the extent entry to always be found first if we do a
 930                          * linear search through the tree, since we want to have
 931                          * the quickest allocation time, and allocating from an
 932                          * extent is faster than allocating from a bitmap.  So
 933                          * if we're inserting a bitmap and we find an entry at
 934                          * this offset, we want to go right, or after this entry
 935                          * logically.  If we are inserting an extent and we've
 936                          * found a bitmap, we want to go left, or before
 937                          * logically.
 938                          */
 939                         if (bitmap) {
 940                                 if (info->bitmap) {
 941                                         WARN_ON_ONCE(1);
 942                                         return -EEXIST;
 943                                 }
 944                                 p = &(*p)->rb_right;
 945                         } else {
 946                                 if (!info->bitmap) {
 947                                         WARN_ON_ONCE(1);
 948                                         return -EEXIST;
 949                                 }
 950                                 p = &(*p)->rb_left;
 951                         }
 952                 }
 953         }
 954
 955         rb_link_node(node, parent, p);
 956         rb_insert_color(node, root);
 957
 958         return 0;
 959 }
 960
 961 /*
 962  * searches the tree for the given offset.
 963  *
 964  * fuzzy - If this is set, then we are trying to make an allocation, and we just
 965  * want a section that has at least bytes size and comes at or after the given
 966  * offset.
 967  */
 968 static struct btrfs_free_space *
 969 tree_search_offset(struct btrfs_free_space_ctl *ctl,
 970                    u64 offset, int bitmap_only, int fuzzy)
 971 {
 972         struct rb_node *n = ctl->free_space_offset.rb_node;
 973         struct btrfs_free_space *entry, *prev = NULL;
 974
 975         /* find entry that is closest to the 'offset' */
 976         while (1) {
 977                 if (!n) {
 978                         entry = NULL;
 979                         break;
 980                 }
 981
 982                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
 983                 prev = entry;
 984
 985                 if (offset < entry->offset)
 986                         n = n->rb_left;
 987                 else if (offset > entry->offset)
 988                         n = n->rb_right;
 989                 else
 990                         break;
 991         }
 992
 993         if (bitmap_only) {
 994                 if (!entry)
 995                         return NULL;
 996                 if (entry->bitmap)
 997                         return entry;
 998
 999                 /*
1000                  * bitmap entry and extent entry may share same offset,
1001                  * in that case, bitmap entry comes after extent entry.
1002                  */
1003                 n = rb_next(n);
1004                 if (!n)
1005                         return NULL;
1006                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1007                 if (entry->offset != offset)
1008                         return NULL;
1009
1010                 WARN_ON(!entry->bitmap);
1011                 return entry;
1012         } else if (entry) {
1013                 if (entry->bitmap) {
1014                         /*
1015                          * if previous extent entry covers the offset,
1016                          * we should return it instead of the bitmap entry
1017                          */
1018                         n = &entry->offset_index;
1019                         while (1) {
1020                                 n = rb_prev(n);
1021                                 if (!n)
1022                                         break;
1023                                 prev = rb_entry(n, struct btrfs_free_space,
1024                                                 offset_index);
1025                                 if (!prev->bitmap) {
1026                                         if (prev->offset + prev->bytes > offset)
1027                                                 entry = prev;
1028                                         break;
1029                                 }
1030                         }
1031                 }
1032                 return entry;
1033         }
1034
1035         if (!prev)
1036                 return NULL;
1037
1038         /* find last entry before the 'offset' */
1039         entry = prev;
1040         if (entry->offset > offset) {
1041                 n = rb_prev(&entry->offset_index);
1042                 if (n) {
1043                         entry = rb_entry(n, struct btrfs_free_space,
1044                                         offset_index);
1045                         BUG_ON(entry->offset > offset);
1046                 } else {
1047                         if (fuzzy)
1048                                 return entry;
1049                         else
1050                                 return NULL;
1051                 }
1052         }
1053
1054         if (entry->bitmap) {
1055                 n = &entry->offset_index;
1056                 while (1) {
1057                         n = rb_prev(n);
1058                         if (!n)
1059                                 break;
1060                         prev = rb_entry(n, struct btrfs_free_space,
1061                                         offset_index);
1062                         if (!prev->bitmap) {
1063                                 if (prev->offset + prev->bytes > offset)
1064                                         return prev;
1065                                 break;
1066                         }
1067                 }
1068                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1069                         return entry;
1070         } else if (entry->offset + entry->bytes > offset)
1071                 return entry;
1072
1073         if (!fuzzy)
1074                 return NULL;
1075
1076         while (1) {
1077                 if (entry->bitmap) {
1078                         if (entry->offset + BITS_PER_BITMAP *
1079                             ctl->unit > offset)
1080                                 break;
1081                 } else {
1082                         if (entry->offset + entry->bytes > offset)
1083                                 break;
1084                 }
1085
1086                 n = rb_next(&entry->offset_index);
1087                 if (!n)
1088                         return NULL;
1089                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1090         }
1091         return entry;
1092 }
1093
1094 static inline void
1095 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1096                     struct btrfs_free_space *info)
1097 {
1098         rb_erase(&info->offset_index, &ctl->free_space_offset);
1099         ctl->free_extents--;
1100 }
1101
1102 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1103                               struct btrfs_free_space *info)
1104 {
1105         __unlink_free_space(ctl, info);
1106         ctl->free_space -= info->bytes;
1107 }
1108
1109 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1110                            struct btrfs_free_space *info)
1111 {
1112         int ret = 0;
1113
1114         BUG_ON(!info->bitmap && !info->bytes);
1115         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1116                                  &info->offset_index, (info->bitmap != NULL));
1117         if (ret)
1118                 return ret;
1119
1120         ctl->free_space += info->bytes;
1121         ctl->free_extents++;
1122         return ret;
1123 }
1124
1125 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1126 {
1127         struct btrfs_block_group_cache *block_group = ctl->private;
1128         u64 max_bytes;
1129         u64 bitmap_bytes;
1130         u64 extent_bytes;
1131         u64 size = block_group->key.offset;
1132         u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1133         int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1134
1135         BUG_ON(ctl->total_bitmaps > max_bitmaps);
1136
1137         /*
1138          * The goal is to keep the total amount of memory used per 1gb of space
1139          * at or below 32k, so we need to adjust how much memory we allow to be
1140          * used by extent based free space tracking
1141          */
1142         if (size < 1024 * 1024 * 1024)
1143                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1144         else
1145                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1146                         div64_u64(size, 1024 * 1024 * 1024);
1147
1148         /*
1149          * we want to account for 1 more bitmap than what we have so we can make
1150          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1151          * we add more bitmaps.
1152          */
1153         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1154
1155         if (bitmap_bytes >= max_bytes) {
1156                 ctl->extents_thresh = 0;
1157                 return;
1158         }
1159
1160         /*
1161          * we want the extent entry threshold to always be at most 1/2 the maxw
1162          * bytes we can have, or whatever is less than that.
1163          */
1164         extent_bytes = max_bytes - bitmap_bytes;
1165         extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1166
1167         ctl->extents_thresh =
1168                 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1169 }
1170
1171 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1172                               struct btrfs_free_space *info, u64 offset,
1173                               u64 bytes)
1174 {
1175         unsigned long start, count;
1176
1177         start = offset_to_bit(info->offset, ctl->unit, offset);
1178         count = bytes_to_bits(bytes, ctl->unit);
1179         BUG_ON(start + count > BITS_PER_BITMAP);
1180
1181         bitmap_clear(info->bitmap, start, count);
1182
1183         info->bytes -= bytes;
1184         ctl->free_space -= bytes;
1185 }
1186
1187 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1188                             struct btrfs_free_space *info, u64 offset,
1189                             u64 bytes)
1190 {
1191         unsigned long start, count;
1192
1193         start = offset_to_bit(info->offset, ctl->unit, offset);
1194         count = bytes_to_bits(bytes, ctl->unit);
1195         BUG_ON(start + count > BITS_PER_BITMAP);
1196
1197         bitmap_set(info->bitmap, start, count);
1198
1199         info->bytes += bytes;
1200         ctl->free_space += bytes;
1201 }
1202
1203 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1204                          struct btrfs_free_space *bitmap_info, u64 *offset,
1205                          u64 *bytes)
1206 {
1207         unsigned long found_bits = 0;
1208         unsigned long bits, i;
1209         unsigned long next_zero;
1210
1211         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1212                           max_t(u64, *offset, bitmap_info->offset));
1213         bits = bytes_to_bits(*bytes, ctl->unit);
1214
1215         for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1216              i < BITS_PER_BITMAP;
1217              i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1218                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1219                                                BITS_PER_BITMAP, i);
1220                 if ((next_zero - i) >= bits) {
1221                         found_bits = next_zero - i;
1222                         break;
1223                 }
1224                 i = next_zero;
1225         }
1226
1227         if (found_bits) {
1228                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1229                 *bytes = (u64)(found_bits) * ctl->unit;
1230                 return 0;
1231         }
1232
1233         return -1;
1234 }
1235
1236 static struct btrfs_free_space *
1237 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
1238 {
1239         struct btrfs_free_space *entry;
1240         struct rb_node *node;
1241         int ret;
1242
1243         if (!ctl->free_space_offset.rb_node)
1244                 return NULL;
1245
1246         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1247         if (!entry)
1248                 return NULL;
1249
1250         for (node = &entry->offset_index; node; node = rb_next(node)) {
1251                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1252                 if (entry->bytes < *bytes)
1253                         continue;
1254
1255                 if (entry->bitmap) {
1256                         ret = search_bitmap(ctl, entry, offset, bytes);
1257                         if (!ret)
1258                                 return entry;
1259                         continue;
1260                 }
1261
1262                 *offset = entry->offset;
1263                 *bytes = entry->bytes;
1264                 return entry;
1265         }
1266
1267         return NULL;
1268 }
1269
1270 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1271                            struct btrfs_free_space *info, u64 offset)
1272 {
1273         info->offset = offset_to_bitmap(ctl, offset);
1274         info->bytes = 0;
1275         link_free_space(ctl, info);
1276         ctl->total_bitmaps++;
1277
1278         ctl->op->recalc_thresholds(ctl);
1279 }
1280
1281 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1282                         struct btrfs_free_space *bitmap_info)
1283 {
1284         unlink_free_space(ctl, bitmap_info);
1285         kfree(bitmap_info->bitmap);
1286         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1287         ctl->total_bitmaps--;
1288         ctl->op->recalc_thresholds(ctl);
1289 }
1290
1291 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1292                               struct btrfs_free_space *bitmap_info,
1293                               u64 *offset, u64 *bytes)
1294 {
1295         u64 end;
1296         u64 search_start, search_bytes;
1297         int ret;
1298
1299 again:
1300         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1301
1302         /*
1303          * XXX - this can go away after a few releases.
1304          *
1305          * since the only user of btrfs_remove_free_space is the tree logging
1306          * stuff, and the only way to test that is under crash conditions, we
1307          * want to have this debug stuff here just in case somethings not
1308          * working.  Search the bitmap for the space we are trying to use to
1309          * make sure its actually there.  If its not there then we need to stop
1310          * because something has gone wrong.
1311          */
1312         search_start = *offset;
1313         search_bytes = *bytes;
1314         search_bytes = min(search_bytes, end - search_start + 1);
1315         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1316         BUG_ON(ret < 0 || search_start != *offset);
1317
1318         if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1319                 bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1);
1320                 *bytes -= end - *offset + 1;
1321                 *offset = end + 1;
1322         } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1323                 bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes);
1324                 *bytes = 0;
1325         }
1326
1327         if (*bytes) {
1328                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1329                 if (!bitmap_info->bytes)
1330                         free_bitmap(ctl, bitmap_info);
1331
1332                 /*
1333                  * no entry after this bitmap, but we still have bytes to
1334                  * remove, so something has gone wrong.
1335                  */
1336                 if (!next)
1337                         return -EINVAL;
1338
1339                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1340                                        offset_index);
1341
1342                 /*
1343                  * if the next entry isn't a bitmap we need to return to let the
1344                  * extent stuff do its work.
1345                  */
1346                 if (!bitmap_info->bitmap)
1347                         return -EAGAIN;
1348
1349                 /*
1350                  * Ok the next item is a bitmap, but it may not actually hold
1351                  * the information for the rest of this free space stuff, so
1352                  * look for it, and if we don't find it return so we can try
1353                  * everything over again.
1354                  */
1355                 search_start = *offset;
1356                 search_bytes = *bytes;
1357                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1358                                     &search_bytes);
1359                 if (ret < 0 || search_start != *offset)
1360                         return -EAGAIN;
1361
1362                 goto again;
1363         } else if (!bitmap_info->bytes)
1364                 free_bitmap(ctl, bitmap_info);
1365
1366         return 0;
1367 }
1368
1369 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1370                                struct btrfs_free_space *info, u64 offset,
1371                                u64 bytes)
1372 {
1373         u64 bytes_to_set = 0;
1374         u64 end;
1375
1376         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1377
1378         bytes_to_set = min(end - offset, bytes);
1379
1380         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1381
1382         return bytes_to_set;
1383
1384 }
1385
1386 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1387                       struct btrfs_free_space *info)
1388 {
1389         struct btrfs_block_group_cache *block_group = ctl->private;
1390
1391         /*
1392          * If we are below the extents threshold then we can add this as an
1393          * extent, and don't have to deal with the bitmap
1394          */
1395         if (ctl->free_extents < ctl->extents_thresh) {
1396                 /*
1397                  * If this block group has some small extents we don't want to
1398                  * use up all of our free slots in the cache with them, we want
1399                  * to reserve them to larger extents, however if we have plent
1400                  * of cache left then go ahead an dadd them, no sense in adding
1401                  * the overhead of a bitmap if we don't have to.
1402                  */
1403                 if (info->bytes <= block_group->sectorsize * 4) {
1404                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1405                                 return false;
1406                 } else {
1407                         return false;
1408                 }
1409         }
1410
1411         /*
1412          * some block groups are so tiny they can't be enveloped by a bitmap, so
1413          * don't even bother to create a bitmap for this
1414          */
1415         if (BITS_PER_BITMAP * block_group->sectorsize >
1416             block_group->key.offset)
1417                 return false;
1418
1419         return true;
1420 }
1421
1422 static struct btrfs_free_space_op free_space_op = {
1423         .recalc_thresholds      = recalculate_thresholds,
1424         .use_bitmap             = use_bitmap,
1425 };
1426
1427 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1428                               struct btrfs_free_space *info)
1429 {
1430         struct btrfs_free_space *bitmap_info;
1431         struct btrfs_block_group_cache *block_group = NULL;
1432         int added = 0;
1433         u64 bytes, offset, bytes_added;
1434         int ret;
1435
1436         bytes = info->bytes;
1437         offset = info->offset;
1438
1439         if (!ctl->op->use_bitmap(ctl, info))
1440                 return 0;
1441
1442         if (ctl->op == &free_space_op)
1443                 block_group = ctl->private;
1444 again:
1445         /*
1446          * Since we link bitmaps right into the cluster we need to see if we
1447          * have a cluster here, and if so and it has our bitmap we need to add
1448          * the free space to that bitmap.
1449          */
1450         if (block_group && !list_empty(&block_group->cluster_list)) {
1451                 struct btrfs_free_cluster *cluster;
1452                 struct rb_node *node;
1453                 struct btrfs_free_space *entry;
1454
1455                 cluster = list_entry(block_group->cluster_list.next,
1456                                      struct btrfs_free_cluster,
1457                                      block_group_list);
1458                 spin_lock(&cluster->lock);
1459                 node = rb_first(&cluster->root);
1460                 if (!node) {
1461                         spin_unlock(&cluster->lock);
1462                         goto no_cluster_bitmap;
1463                 }
1464
1465                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1466                 if (!entry->bitmap) {
1467                         spin_unlock(&cluster->lock);
1468                         goto no_cluster_bitmap;
1469                 }
1470
1471                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1472                         bytes_added = add_bytes_to_bitmap(ctl, entry,
1473                                                           offset, bytes);
1474                         bytes -= bytes_added;
1475                         offset += bytes_added;
1476                 }
1477                 spin_unlock(&cluster->lock);
1478                 if (!bytes) {
1479                         ret = 1;
1480                         goto out;
1481                 }
1482         }
1483
1484 no_cluster_bitmap:
1485         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1486                                          1, 0);
1487         if (!bitmap_info) {
1488                 BUG_ON(added);
1489                 goto new_bitmap;
1490         }
1491
1492         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1493         bytes -= bytes_added;
1494         offset += bytes_added;
1495         added = 0;
1496
1497         if (!bytes) {
1498                 ret = 1;
1499                 goto out;
1500         } else
1501                 goto again;
1502
1503 new_bitmap:
1504         if (info && info->bitmap) {
1505                 add_new_bitmap(ctl, info, offset);
1506                 added = 1;
1507                 info = NULL;
1508                 goto again;
1509         } else {
1510                 spin_unlock(&ctl->tree_lock);
1511
1512                 /* no pre-allocated info, allocate a new one */
1513                 if (!info) {
1514                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
1515                                                  GFP_NOFS);
1516                         if (!info) {
1517                                 spin_lock(&ctl->tree_lock);
1518                                 ret = -ENOMEM;
1519                                 goto out;
1520                         }
1521                 }
1522
1523                 /* allocate the bitmap */
1524                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1525                 spin_lock(&ctl->tree_lock);
1526                 if (!info->bitmap) {
1527                         ret = -ENOMEM;
1528                         goto out;
1529                 }
1530                 goto again;
1531         }
1532
1533 out:
1534         if (info) {
1535                 if (info->bitmap)
1536                         kfree(info->bitmap);
1537                 kmem_cache_free(btrfs_free_space_cachep, info);
1538         }
1539
1540         return ret;
1541 }
1542
1543 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1544                           struct btrfs_free_space *info, bool update_stat)
1545 {
1546         struct btrfs_free_space *left_info;
1547         struct btrfs_free_space *right_info;
1548         bool merged = false;
1549         u64 offset = info->offset;
1550         u64 bytes = info->bytes;
1551
1552         /*
1553          * first we want to see if there is free space adjacent to the range we
1554          * are adding, if there is remove that struct and add a new one to
1555          * cover the entire range
1556          */
1557         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1558         if (right_info && rb_prev(&right_info->offset_index))
1559                 left_info = rb_entry(rb_prev(&right_info->offset_index),
1560                                      struct btrfs_free_space, offset_index);
1561         else
1562                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1563
1564         if (right_info && !right_info->bitmap) {
1565                 if (update_stat)
1566                         unlink_free_space(ctl, right_info);
1567                 else
1568                         __unlink_free_space(ctl, right_info);
1569                 info->bytes += right_info->bytes;
1570                 kmem_cache_free(btrfs_free_space_cachep, right_info);
1571                 merged = true;
1572         }
1573
1574         if (left_info && !left_info->bitmap &&
1575             left_info->offset + left_info->bytes == offset) {
1576                 if (update_stat)
1577                         unlink_free_space(ctl, left_info);
1578                 else
1579                         __unlink_free_space(ctl, left_info);
1580                 info->offset = left_info->offset;
1581                 info->bytes += left_info->bytes;
1582                 kmem_cache_free(btrfs_free_space_cachep, left_info);
1583                 merged = true;
1584         }
1585
1586         return merged;
1587 }
1588
1589 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1590                            u64 offset, u64 bytes)
1591 {
1592         struct btrfs_free_space *info;
1593         int ret = 0;
1594
1595         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1596         if (!info)
1597                 return -ENOMEM;
1598
1599         info->offset = offset;
1600         info->bytes = bytes;
1601
1602         spin_lock(&ctl->tree_lock);
1603
1604         if (try_merge_free_space(ctl, info, true))
1605                 goto link;
1606
1607         /*
1608          * There was no extent directly to the left or right of this new
1609          * extent then we know we're going to have to allocate a new extent, so
1610          * before we do that see if we need to drop this into a bitmap
1611          */
1612         ret = insert_into_bitmap(ctl, info);
1613         if (ret < 0) {
1614                 goto out;
1615         } else if (ret) {
1616                 ret = 0;
1617                 goto out;
1618         }
1619 link:
1620         ret = link_free_space(ctl, info);
1621         if (ret)
1622                 kmem_cache_free(btrfs_free_space_cachep, info);
1623 out:
1624         spin_unlock(&ctl->tree_lock);
1625
1626         if (ret) {
1627                 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1628                 BUG_ON(ret == -EEXIST);
1629         }
1630
1631         return ret;
1632 }
1633
1634 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1635                             u64 offset, u64 bytes)
1636 {
1637         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1638         struct btrfs_free_space *info;
1639         struct btrfs_free_space *next_info = NULL;
1640         int ret = 0;
1641
1642         spin_lock(&ctl->tree_lock);
1643
1644 again:
1645         info = tree_search_offset(ctl, offset, 0, 0);
1646         if (!info) {
1647                 /*
1648                  * oops didn't find an extent that matched the space we wanted
1649                  * to remove, look for a bitmap instead
1650                  */
1651                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1652                                           1, 0);
1653                 if (!info) {
1654                         WARN_ON(1);
1655                         goto out_lock;
1656                 }
1657         }
1658
1659         if (info->bytes < bytes && rb_next(&info->offset_index)) {
1660                 u64 end;
1661                 next_info = rb_entry(rb_next(&info->offset_index),
1662                                              struct btrfs_free_space,
1663                                              offset_index);
1664
1665                 if (next_info->bitmap)
1666                         end = next_info->offset +
1667                               BITS_PER_BITMAP * ctl->unit - 1;
1668                 else
1669                         end = next_info->offset + next_info->bytes;
1670
1671                 if (next_info->bytes < bytes ||
1672                     next_info->offset > offset || offset > end) {
1673                         printk(KERN_CRIT "Found free space at %llu, size %llu,"
1674                               " trying to use %llu\n",
1675                               (unsigned long long)info->offset,
1676                               (unsigned long long)info->bytes,
1677                               (unsigned long long)bytes);
1678                         WARN_ON(1);
1679                         ret = -EINVAL;
1680                         goto out_lock;
1681                 }
1682
1683                 info = next_info;
1684         }
1685
1686         if (info->bytes == bytes) {
1687                 unlink_free_space(ctl, info);
1688                 if (info->bitmap) {
1689                         kfree(info->bitmap);
1690                         ctl->total_bitmaps--;
1691                 }
1692                 kmem_cache_free(btrfs_free_space_cachep, info);
1693                 goto out_lock;
1694         }
1695
1696         if (!info->bitmap && info->offset == offset) {
1697                 unlink_free_space(ctl, info);
1698                 info->offset += bytes;
1699                 info->bytes -= bytes;
1700                 link_free_space(ctl, info);
1701                 goto out_lock;
1702         }
1703
1704         if (!info->bitmap && info->offset <= offset &&
1705             info->offset + info->bytes >= offset + bytes) {
1706                 u64 old_start = info->offset;
1707                 /*
1708                  * we're freeing space in the middle of the info,
1709                  * this can happen during tree log replay
1710                  *
1711                  * first unlink the old info and then
1712                  * insert it again after the hole we're creating
1713                  */
1714                 unlink_free_space(ctl, info);
1715                 if (offset + bytes < info->offset + info->bytes) {
1716                         u64 old_end = info->offset + info->bytes;
1717
1718                         info->offset = offset + bytes;
1719                         info->bytes = old_end - info->offset;
1720                         ret = link_free_space(ctl, info);
1721                         WARN_ON(ret);
1722                         if (ret)
1723                                 goto out_lock;
1724                 } else {
1725                         /* the hole we're creating ends at the end
1726                          * of the info struct, just free the info
1727                          */
1728                         kmem_cache_free(btrfs_free_space_cachep, info);
1729                 }
1730                 spin_unlock(&ctl->tree_lock);
1731
1732                 /* step two, insert a new info struct to cover
1733                  * anything before the hole
1734                  */
1735                 ret = btrfs_add_free_space(block_group, old_start,
1736                                            offset - old_start);
1737                 WARN_ON(ret);
1738                 goto out;
1739         }
1740
1741         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1742         if (ret == -EAGAIN)
1743                 goto again;
1744         BUG_ON(ret);
1745 out_lock:
1746         spin_unlock(&ctl->tree_lock);
1747 out:
1748         return ret;
1749 }
1750
1751 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1752                            u64 bytes)
1753 {
1754         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1755         struct btrfs_free_space *info;
1756         struct rb_node *n;
1757         int count = 0;
1758
1759         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1760                 info = rb_entry(n, struct btrfs_free_space, offset_index);
1761                 if (info->bytes >= bytes)
1762                         count++;
1763                 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1764                        (unsigned long long)info->offset,
1765                        (unsigned long long)info->bytes,
1766                        (info->bitmap) ? "yes" : "no");
1767         }
1768         printk(KERN_INFO "block group has cluster?: %s\n",
1769                list_empty(&block_group->cluster_list) ? "no" : "yes");
1770         printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1771                "\n", count);
1772 }
1773
1774 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
1775 {
1776         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1777
1778         spin_lock_init(&ctl->tree_lock);
1779         ctl->unit = block_group->sectorsize;
1780         ctl->start = block_group->key.objectid;
1781         ctl->private = block_group;
1782         ctl->op = &free_space_op;
1783
1784         /*
1785          * we only want to have 32k of ram per block group for keeping
1786          * track of free space, and if we pass 1/2 of that we want to
1787          * start converting things over to using bitmaps
1788          */
1789         ctl->extents_thresh = ((1024 * 32) / 2) /
1790                                 sizeof(struct btrfs_free_space);
1791 }
1792
1793 /*
1794  * for a given cluster, put all of its extents back into the free
1795  * space cache.  If the block group passed doesn't match the block group
1796  * pointed to by the cluster, someone else raced in and freed the
1797  * cluster already.  In that case, we just return without changing anything
1798  */
1799 static int
1800 __btrfs_return_cluster_to_free_space(
1801                              struct btrfs_block_group_cache *block_group,
1802                              struct btrfs_free_cluster *cluster)
1803 {
1804         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1805         struct btrfs_free_space *entry;
1806         struct rb_node *node;
1807
1808         spin_lock(&cluster->lock);
1809         if (cluster->block_group != block_group)
1810                 goto out;
1811
1812         cluster->block_group = NULL;
1813         cluster->window_start = 0;
1814         list_del_init(&cluster->block_group_list);
1815
1816         node = rb_first(&cluster->root);
1817         while (node) {
1818                 bool bitmap;
1819
1820                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1821                 node = rb_next(&entry->offset_index);
1822                 rb_erase(&entry->offset_index, &cluster->root);
1823
1824                 bitmap = (entry->bitmap != NULL);
1825                 if (!bitmap)
1826                         try_merge_free_space(ctl, entry, false);
1827                 tree_insert_offset(&ctl->free_space_offset,
1828                                    entry->offset, &entry->offset_index, bitmap);
1829         }
1830         cluster->root = RB_ROOT;
1831
1832 out:
1833         spin_unlock(&cluster->lock);
1834         btrfs_put_block_group(block_group);
1835         return 0;
1836 }
1837
1838 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
1839 {
1840         struct btrfs_free_space *info;
1841         struct rb_node *node;
1842
1843         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
1844                 info = rb_entry(node, struct btrfs_free_space, offset_index);
1845                 if (!info->bitmap) {
1846                         unlink_free_space(ctl, info);
1847                         kmem_cache_free(btrfs_free_space_cachep, info);
1848                 } else {
1849                         free_bitmap(ctl, info);
1850                 }
1851                 if (need_resched()) {
1852                         spin_unlock(&ctl->tree_lock);
1853                         cond_resched();
1854                         spin_lock(&ctl->tree_lock);
1855                 }
1856         }
1857 }
1858
1859 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
1860 {
1861         spin_lock(&ctl->tree_lock);
1862         __btrfs_remove_free_space_cache_locked(ctl);
1863         spin_unlock(&ctl->tree_lock);
1864 }
1865
1866 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
1867 {
1868         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1869         struct btrfs_free_cluster *cluster;
1870         struct list_head *head;
1871
1872         spin_lock(&ctl->tree_lock);
1873         while ((head = block_group->cluster_list.next) !=
1874                &block_group->cluster_list) {
1875                 cluster = list_entry(head, struct btrfs_free_cluster,
1876                                      block_group_list);
1877
1878                 WARN_ON(cluster->block_group != block_group);
1879                 __btrfs_return_cluster_to_free_space(block_group, cluster);
1880                 if (need_resched()) {
1881                         spin_unlock(&ctl->tree_lock);
1882                         cond_resched();
1883                         spin_lock(&ctl->tree_lock);
1884                 }
1885         }
1886         __btrfs_remove_free_space_cache_locked(ctl);
1887         spin_unlock(&ctl->tree_lock);
1888
1889 }
1890
1891 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
1892                                u64 offset, u64 bytes, u64 empty_size)
1893 {
1894         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1895         struct btrfs_free_space *entry = NULL;
1896         u64 bytes_search = bytes + empty_size;
1897         u64 ret = 0;
1898
1899         spin_lock(&ctl->tree_lock);
1900         entry = find_free_space(ctl, &offset, &bytes_search);
1901         if (!entry)
1902                 goto out;
1903
1904         ret = offset;
1905         if (entry->bitmap) {
1906                 bitmap_clear_bits(ctl, entry, offset, bytes);
1907                 if (!entry->bytes)
1908                         free_bitmap(ctl, entry);
1909         } else {
1910                 unlink_free_space(ctl, entry);
1911                 entry->offset += bytes;
1912                 entry->bytes -= bytes;
1913                 if (!entry->bytes)
1914                         kmem_cache_free(btrfs_free_space_cachep, entry);
1915                 else
1916                         link_free_space(ctl, entry);
1917         }
1918
1919 out:
1920         spin_unlock(&ctl->tree_lock);
1921
1922         return ret;
1923 }
1924
1925 /*
1926  * given a cluster, put all of its extents back into the free space
1927  * cache.  If a block group is passed, this function will only free
1928  * a cluster that belongs to the passed block group.
1929  *
1930  * Otherwise, it'll get a reference on the block group pointed to by the
1931  * cluster and remove the cluster from it.
1932  */
1933 int btrfs_return_cluster_to_free_space(
1934                                struct btrfs_block_group_cache *block_group,
1935                                struct btrfs_free_cluster *cluster)
1936 {
1937         struct btrfs_free_space_ctl *ctl;
1938         int ret;
1939
1940         /* first, get a safe pointer to the block group */
1941         spin_lock(&cluster->lock);
1942         if (!block_group) {
1943                 block_group = cluster->block_group;
1944                 if (!block_group) {
1945                         spin_unlock(&cluster->lock);
1946                         return 0;
1947                 }
1948         } else if (cluster->block_group != block_group) {
1949                 /* someone else has already freed it don't redo their work */
1950                 spin_unlock(&cluster->lock);
1951                 return 0;
1952         }
1953         atomic_inc(&block_group->count);
1954         spin_unlock(&cluster->lock);
1955
1956         ctl = block_group->free_space_ctl;
1957
1958         /* now return any extents the cluster had on it */
1959         spin_lock(&ctl->tree_lock);
1960         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
1961         spin_unlock(&ctl->tree_lock);
1962
1963         /* finally drop our ref */
1964         btrfs_put_block_group(block_group);
1965         return ret;
1966 }
1967
1968 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
1969                                    struct btrfs_free_cluster *cluster,
1970                                    struct btrfs_free_space *entry,
1971                                    u64 bytes, u64 min_start)
1972 {
1973         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1974         int err;
1975         u64 search_start = cluster->window_start;
1976         u64 search_bytes = bytes;
1977         u64 ret = 0;
1978
1979         search_start = min_start;
1980         search_bytes = bytes;
1981
1982         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
1983         if (err)
1984                 return 0;
1985
1986         ret = search_start;
1987         bitmap_clear_bits(ctl, entry, ret, bytes);
1988
1989         return ret;
1990 }
1991
1992 /*
1993  * given a cluster, try to allocate 'bytes' from it, returns 0
1994  * if it couldn't find anything suitably large, or a logical disk offset
1995  * if things worked out
1996  */
1997 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
1998                              struct btrfs_free_cluster *cluster, u64 bytes,
1999                              u64 min_start)
2000 {
2001         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2002         struct btrfs_free_space *entry = NULL;
2003         struct rb_node *node;
2004         u64 ret = 0;
2005
2006         spin_lock(&cluster->lock);
2007         if (bytes > cluster->max_size)
2008                 goto out;
2009
2010         if (cluster->block_group != block_group)
2011                 goto out;
2012
2013         node = rb_first(&cluster->root);
2014         if (!node)
2015                 goto out;
2016
2017         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2018         while(1) {
2019                 if (entry->bytes < bytes ||
2020                     (!entry->bitmap && entry->offset < min_start)) {
2021                         node = rb_next(&entry->offset_index);
2022                         if (!node)
2023                                 break;
2024                         entry = rb_entry(node, struct btrfs_free_space,
2025                                          offset_index);
2026                         continue;
2027                 }
2028
2029                 if (entry->bitmap) {
2030                         ret = btrfs_alloc_from_bitmap(block_group,
2031                                                       cluster, entry, bytes,
2032                                                       min_start);
2033                         if (ret == 0) {
2034                                 node = rb_next(&entry->offset_index);
2035                                 if (!node)
2036                                         break;
2037                                 entry = rb_entry(node, struct btrfs_free_space,
2038                                                  offset_index);
2039                                 continue;
2040                         }
2041                 } else {
2042
2043                         ret = entry->offset;
2044
2045                         entry->offset += bytes;
2046                         entry->bytes -= bytes;
2047                 }
2048
2049                 if (entry->bytes == 0)
2050                         rb_erase(&entry->offset_index, &cluster->root);
2051                 break;
2052         }
2053 out:
2054         spin_unlock(&cluster->lock);
2055
2056         if (!ret)
2057                 return 0;
2058
2059         spin_lock(&ctl->tree_lock);
2060
2061         ctl->free_space -= bytes;
2062         if (entry->bytes == 0) {
2063                 ctl->free_extents--;
2064                 if (entry->bitmap) {
2065                         kfree(entry->bitmap);
2066                         ctl->total_bitmaps--;
2067                         ctl->op->recalc_thresholds(ctl);
2068                 }
2069                 kmem_cache_free(btrfs_free_space_cachep, entry);
2070         }
2071
2072         spin_unlock(&ctl->tree_lock);
2073
2074         return ret;
2075 }
2076
2077 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2078                                 struct btrfs_free_space *entry,
2079                                 struct btrfs_free_cluster *cluster,
2080                                 u64 offset, u64 bytes, u64 min_bytes)
2081 {
2082         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2083         unsigned long next_zero;
2084         unsigned long i;
2085         unsigned long search_bits;
2086         unsigned long total_bits;
2087         unsigned long found_bits;
2088         unsigned long start = 0;
2089         unsigned long total_found = 0;
2090         int ret;
2091         bool found = false;
2092
2093         i = offset_to_bit(entry->offset, block_group->sectorsize,
2094                           max_t(u64, offset, entry->offset));
2095         search_bits = bytes_to_bits(bytes, block_group->sectorsize);
2096         total_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2097
2098 again:
2099         found_bits = 0;
2100         for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2101              i < BITS_PER_BITMAP;
2102              i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2103                 next_zero = find_next_zero_bit(entry->bitmap,
2104                                                BITS_PER_BITMAP, i);
2105                 if (next_zero - i >= search_bits) {
2106                         found_bits = next_zero - i;
2107                         break;
2108                 }
2109                 i = next_zero;
2110         }
2111
2112         if (!found_bits)
2113                 return -ENOSPC;
2114
2115         if (!found) {
2116                 start = i;
2117                 found = true;
2118         }
2119
2120         total_found += found_bits;
2121
2122         if (cluster->max_size < found_bits * block_group->sectorsize)
2123                 cluster->max_size = found_bits * block_group->sectorsize;
2124
2125         if (total_found < total_bits) {
2126                 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
2127                 if (i - start > total_bits * 2) {
2128                         total_found = 0;
2129                         cluster->max_size = 0;
2130                         found = false;
2131                 }
2132                 goto again;
2133         }
2134
2135         cluster->window_start = start * block_group->sectorsize +
2136                 entry->offset;
2137         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2138         ret = tree_insert_offset(&cluster->root, entry->offset,
2139                                  &entry->offset_index, 1);
2140         BUG_ON(ret);
2141
2142         return 0;
2143 }
2144
2145 /*
2146  * This searches the block group for just extents to fill the cluster with.
2147  */
2148 static noinline int
2149 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2150                         struct btrfs_free_cluster *cluster,
2151                         struct list_head *bitmaps, u64 offset, u64 bytes,
2152                         u64 min_bytes)
2153 {
2154         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2155         struct btrfs_free_space *first = NULL;
2156         struct btrfs_free_space *entry = NULL;
2157         struct btrfs_free_space *prev = NULL;
2158         struct btrfs_free_space *last;
2159         struct rb_node *node;
2160         u64 window_start;
2161         u64 window_free;
2162         u64 max_extent;
2163         u64 max_gap = 128 * 1024;
2164
2165         entry = tree_search_offset(ctl, offset, 0, 1);
2166         if (!entry)
2167                 return -ENOSPC;
2168
2169         /*
2170          * We don't want bitmaps, so just move along until we find a normal
2171          * extent entry.
2172          */
2173         while (entry->bitmap) {
2174                 if (list_empty(&entry->list))
2175                         list_add_tail(&entry->list, bitmaps);
2176                 node = rb_next(&entry->offset_index);
2177                 if (!node)
2178                         return -ENOSPC;
2179                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2180         }
2181
2182         window_start = entry->offset;
2183         window_free = entry->bytes;
2184         max_extent = entry->bytes;
2185         first = entry;
2186         last = entry;
2187         prev = entry;
2188
2189         while (window_free <= min_bytes) {
2190                 node = rb_next(&entry->offset_index);
2191                 if (!node)
2192                         return -ENOSPC;
2193                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2194
2195                 if (entry->bitmap) {
2196                         if (list_empty(&entry->list))
2197                                 list_add_tail(&entry->list, bitmaps);
2198                         continue;
2199                 }
2200
2201                 /*
2202                  * we haven't filled the empty size and the window is
2203                  * very large.  reset and try again
2204                  */
2205                 if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
2206                     entry->offset - window_start > (min_bytes * 2)) {
2207                         first = entry;
2208                         window_start = entry->offset;
2209                         window_free = entry->bytes;
2210                         last = entry;
2211                         max_extent = entry->bytes;
2212                 } else {
2213                         last = entry;
2214                         window_free += entry->bytes;
2215                         if (entry->bytes > max_extent)
2216                                 max_extent = entry->bytes;
2217                 }
2218                 prev = entry;
2219         }
2220
2221         cluster->window_start = first->offset;
2222
2223         node = &first->offset_index;
2224
2225         /*
2226          * now we've found our entries, pull them out of the free space
2227          * cache and put them into the cluster rbtree
2228          */
2229         do {
2230                 int ret;
2231
2232                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2233                 node = rb_next(&entry->offset_index);
2234                 if (entry->bitmap)
2235                         continue;
2236
2237                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2238                 ret = tree_insert_offset(&cluster->root, entry->offset,
2239                                          &entry->offset_index, 0);
2240                 BUG_ON(ret);
2241         } while (node && entry != last);
2242
2243         cluster->max_size = max_extent;
2244
2245         return 0;
2246 }
2247
2248 /*
2249  * This specifically looks for bitmaps that may work in the cluster, we assume
2250  * that we have already failed to find extents that will work.
2251  */
2252 static noinline int
2253 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2254                      struct btrfs_free_cluster *cluster,
2255                      struct list_head *bitmaps, u64 offset, u64 bytes,
2256                      u64 min_bytes)
2257 {
2258         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2259         struct btrfs_free_space *entry;
2260         struct rb_node *node;
2261         int ret = -ENOSPC;
2262
2263         if (ctl->total_bitmaps == 0)
2264                 return -ENOSPC;
2265
2266         /*
2267          * First check our cached list of bitmaps and see if there is an entry
2268          * here that will work.
2269          */
2270         list_for_each_entry(entry, bitmaps, list) {
2271                 if (entry->bytes < min_bytes)
2272                         continue;
2273                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2274                                            bytes, min_bytes);
2275                 if (!ret)
2276                         return 0;
2277         }
2278
2279         /*
2280          * If we do have entries on our list and we are here then we didn't find
2281          * anything, so go ahead and get the next entry after the last entry in
2282          * this list and start the search from there.
2283          */
2284         if (!list_empty(bitmaps)) {
2285                 entry = list_entry(bitmaps->prev, struct btrfs_free_space,
2286                                    list);
2287                 node = rb_next(&entry->offset_index);
2288                 if (!node)
2289                         return -ENOSPC;
2290                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2291                 goto search;
2292         }
2293
2294         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1);
2295         if (!entry)
2296                 return -ENOSPC;
2297
2298 search:
2299         node = &entry->offset_index;
2300         do {
2301                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2302                 node = rb_next(&entry->offset_index);
2303                 if (!entry->bitmap)
2304                         continue;
2305                 if (entry->bytes < min_bytes)
2306                         continue;
2307                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2308                                            bytes, min_bytes);
2309         } while (ret && node);
2310
2311         return ret;
2312 }
2313
2314 /*
2315  * here we try to find a cluster of blocks in a block group.  The goal
2316  * is to find at least bytes free and up to empty_size + bytes free.
2317  * We might not find them all in one contiguous area.
2318  *
2319  * returns zero and sets up cluster if things worked out, otherwise
2320  * it returns -enospc
2321  */
2322 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2323                              struct btrfs_root *root,
2324                              struct btrfs_block_group_cache *block_group,
2325                              struct btrfs_free_cluster *cluster,
2326                              u64 offset, u64 bytes, u64 empty_size)
2327 {
2328         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2329         struct list_head bitmaps;
2330         struct btrfs_free_space *entry, *tmp;
2331         u64 min_bytes;
2332         int ret;
2333
2334         /* for metadata, allow allocates with more holes */
2335         if (btrfs_test_opt(root, SSD_SPREAD)) {
2336                 min_bytes = bytes + empty_size;
2337         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2338                 /*
2339                  * we want to do larger allocations when we are
2340                  * flushing out the delayed refs, it helps prevent
2341                  * making more work as we go along.
2342                  */
2343                 if (trans->transaction->delayed_refs.flushing)
2344                         min_bytes = max(bytes, (bytes + empty_size) >> 1);
2345                 else
2346                         min_bytes = max(bytes, (bytes + empty_size) >> 4);
2347         } else
2348                 min_bytes = max(bytes, (bytes + empty_size) >> 2);
2349
2350         spin_lock(&ctl->tree_lock);
2351
2352         /*
2353          * If we know we don't have enough space to make a cluster don't even
2354          * bother doing all the work to try and find one.
2355          */
2356         if (ctl->free_space < min_bytes) {
2357                 spin_unlock(&ctl->tree_lock);
2358                 return -ENOSPC;
2359         }
2360
2361         spin_lock(&cluster->lock);
2362
2363         /* someone already found a cluster, hooray */
2364         if (cluster->block_group) {
2365                 ret = 0;
2366                 goto out;
2367         }
2368
2369         INIT_LIST_HEAD(&bitmaps);
2370         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2371                                       bytes, min_bytes);
2372         if (ret)
2373                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2374                                            offset, bytes, min_bytes);
2375
2376         /* Clear our temporary list */
2377         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2378                 list_del_init(&entry->list);
2379
2380         if (!ret) {
2381                 atomic_inc(&block_group->count);
2382                 list_add_tail(&cluster->block_group_list,
2383                               &block_group->cluster_list);
2384                 cluster->block_group = block_group;
2385         }
2386 out:
2387         spin_unlock(&cluster->lock);
2388         spin_unlock(&ctl->tree_lock);
2389
2390         return ret;
2391 }
2392
2393 /*
2394  * simple code to zero out a cluster
2395  */
2396 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2397 {
2398         spin_lock_init(&cluster->lock);
2399         spin_lock_init(&cluster->refill_lock);
2400         cluster->root = RB_ROOT;
2401         cluster->max_size = 0;
2402         INIT_LIST_HEAD(&cluster->block_group_list);
2403         cluster->block_group = NULL;
2404 }
2405
2406 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2407                            u64 *trimmed, u64 start, u64 end, u64 minlen)
2408 {
2409         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2410         struct btrfs_free_space *entry = NULL;
2411         struct btrfs_fs_info *fs_info = block_group->fs_info;
2412         u64 bytes = 0;
2413         u64 actually_trimmed;
2414         int ret = 0;
2415
2416         *trimmed = 0;
2417
2418         while (start < end) {
2419                 spin_lock(&ctl->tree_lock);
2420
2421                 if (ctl->free_space < minlen) {
2422                         spin_unlock(&ctl->tree_lock);
2423                         break;
2424                 }
2425
2426                 entry = tree_search_offset(ctl, start, 0, 1);
2427                 if (!entry)
2428                         entry = tree_search_offset(ctl,
2429                                                    offset_to_bitmap(ctl, start),
2430                                                    1, 1);
2431
2432                 if (!entry || entry->offset >= end) {
2433                         spin_unlock(&ctl->tree_lock);
2434                         break;
2435                 }
2436
2437                 if (entry->bitmap) {
2438                         ret = search_bitmap(ctl, entry, &start, &bytes);
2439                         if (!ret) {
2440                                 if (start >= end) {
2441                                         spin_unlock(&ctl->tree_lock);
2442                                         break;
2443                                 }
2444                                 bytes = min(bytes, end - start);
2445                                 bitmap_clear_bits(ctl, entry, start, bytes);
2446                                 if (entry->bytes == 0)
2447                                         free_bitmap(ctl, entry);
2448                         } else {
2449                                 start = entry->offset + BITS_PER_BITMAP *
2450                                         block_group->sectorsize;
2451                                 spin_unlock(&ctl->tree_lock);
2452                                 ret = 0;
2453                                 continue;
2454                         }
2455                 } else {
2456                         start = entry->offset;
2457                         bytes = min(entry->bytes, end - start);
2458                         unlink_free_space(ctl, entry);
2459                         kmem_cache_free(btrfs_free_space_cachep, entry);
2460                 }
2461
2462                 spin_unlock(&ctl->tree_lock);
2463
2464                 if (bytes >= minlen) {
2465                         int update_ret;
2466                         update_ret = btrfs_update_reserved_bytes(block_group,
2467                                                                  bytes, 1, 1);
2468
2469                         ret = btrfs_error_discard_extent(fs_info->extent_root,
2470                                                          start,
2471                                                          bytes,
2472                                                          &actually_trimmed);
2473
2474                         btrfs_add_free_space(block_group, start, bytes);
2475                         if (!update_ret)
2476                                 btrfs_update_reserved_bytes(block_group,
2477                                                             bytes, 0, 1);
2478
2479                         if (ret)
2480                                 break;
2481                         *trimmed += actually_trimmed;
2482                 }
2483                 start += bytes;
2484                 bytes = 0;
2485
2486                 if (fatal_signal_pending(current)) {
2487                         ret = -ERESTARTSYS;
2488                         break;
2489                 }
2490
2491                 cond_resched();
2492         }
2493
2494         return ret;
2495 }
2496
2497 /*
2498  * Find the left-most item in the cache tree, and then return the
2499  * smallest inode number in the item.
2500  *
2501  * Note: the returned inode number may not be the smallest one in
2502  * the tree, if the left-most item is a bitmap.
2503  */
2504 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2505 {
2506         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2507         struct btrfs_free_space *entry = NULL;
2508         u64 ino = 0;
2509
2510         spin_lock(&ctl->tree_lock);
2511
2512         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2513                 goto out;
2514
2515         entry = rb_entry(rb_first(&ctl->free_space_offset),
2516                          struct btrfs_free_space, offset_index);
2517
2518         if (!entry->bitmap) {
2519                 ino = entry->offset;
2520
2521                 unlink_free_space(ctl, entry);
2522                 entry->offset++;
2523                 entry->bytes--;
2524                 if (!entry->bytes)
2525                         kmem_cache_free(btrfs_free_space_cachep, entry);
2526                 else
2527                         link_free_space(ctl, entry);
2528         } else {
2529                 u64 offset = 0;
2530                 u64 count = 1;
2531                 int ret;
2532
2533                 ret = search_bitmap(ctl, entry, &offset, &count);
2534                 BUG_ON(ret);
2535
2536                 ino = offset;
2537                 bitmap_clear_bits(ctl, entry, offset, 1);
2538                 if (entry->bytes == 0)
2539                         free_bitmap(ctl, entry);
2540         }
2541 out:
2542         spin_unlock(&ctl->tree_lock);
2543
2544         return ino;
2545 }
2546
2547 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2548                                     struct btrfs_path *path)
2549 {
2550         struct inode *inode = NULL;
2551
2552         spin_lock(&root->cache_lock);
2553         if (root->cache_inode)
2554                 inode = igrab(root->cache_inode);
2555         spin_unlock(&root->cache_lock);
2556         if (inode)
2557                 return inode;
2558
2559         inode = __lookup_free_space_inode(root, path, 0);
2560         if (IS_ERR(inode))
2561                 return inode;
2562
2563         spin_lock(&root->cache_lock);
2564         if (!btrfs_fs_closing(root->fs_info))
2565                 root->cache_inode = igrab(inode);
2566         spin_unlock(&root->cache_lock);
2567
2568         return inode;
2569 }
2570
2571 int create_free_ino_inode(struct btrfs_root *root,
2572                           struct btrfs_trans_handle *trans,
2573                           struct btrfs_path *path)
2574 {
2575         return __create_free_space_inode(root, trans, path,
2576                                          BTRFS_FREE_INO_OBJECTID, 0);
2577 }
2578
2579 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2580 {
2581         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2582         struct btrfs_path *path;
2583         struct inode *inode;
2584         int ret = 0;
2585         u64 root_gen = btrfs_root_generation(&root->root_item);
2586
2587         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2588                 return 0;
2589
2590         /*
2591          * If we're unmounting then just return, since this does a search on the
2592          * normal root and not the commit root and we could deadlock.
2593          */
2594         if (btrfs_fs_closing(fs_info))
2595                 return 0;
2596
2597         path = btrfs_alloc_path();
2598         if (!path)
2599                 return 0;
2600
2601         inode = lookup_free_ino_inode(root, path);
2602         if (IS_ERR(inode))
2603                 goto out;
2604
2605         if (root_gen != BTRFS_I(inode)->generation)
2606                 goto out_put;
2607
2608         ret = __load_free_space_cache(root, inode, ctl, path, 0);
2609
2610         if (ret < 0)
2611                 printk(KERN_ERR "btrfs: failed to load free ino cache for "
2612                        "root %llu\n", root->root_key.objectid);
2613 out_put:
2614         iput(inode);
2615 out:
2616         btrfs_free_path(path);
2617         return ret;
2618 }
2619
2620 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2621                               struct btrfs_trans_handle *trans,
2622                               struct btrfs_path *path)
2623 {
2624         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2625         struct inode *inode;
2626         int ret;
2627
2628         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2629                 return 0;
2630
2631         inode = lookup_free_ino_inode(root, path);
2632         if (IS_ERR(inode))
2633                 return 0;
2634
2635         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2636         if (ret < 0)
2637                 printk(KERN_ERR "btrfs: failed to write free ino cache "
2638                        "for root %llu\n", root->root_key.objectid);
2639
2640         iput(inode);
2641         return ret;
2642 }