fs/btrfs/free-space-cache.c

   1 /*
   2  * Copyright (C) 2008 Red Hat.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/pagemap.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/math64.h>
  23 #include <linux/ratelimit.h>
  24 #include "ctree.h"
  25 #include "free-space-cache.h"
  26 #include "transaction.h"
  27 #include "disk-io.h"
  28 #include "extent_io.h"
  29 #include "inode-map.h"
  30
  31 #define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
  32 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
  33
  34 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  35                            struct btrfs_free_space *info);
  36 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  37                               struct btrfs_free_space *info);
  38
  39 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  40                                                struct btrfs_path *path,
  41                                                u64 offset)
  42 {
  43         struct btrfs_key key;
  44         struct btrfs_key location;
  45         struct btrfs_disk_key disk_key;
  46         struct btrfs_free_space_header *header;
  47         struct extent_buffer *leaf;
  48         struct inode *inode = NULL;
  49         int ret;
  50
  51         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  52         key.offset = offset;
  53         key.type = 0;
  54
  55         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  56         if (ret < 0)
  57                 return ERR_PTR(ret);
  58         if (ret > 0) {
  59                 btrfs_release_path(path);
  60                 return ERR_PTR(-ENOENT);
  61         }
  62
  63         leaf = path->nodes[0];
  64         header = btrfs_item_ptr(leaf, path->slots[0],
  65                                 struct btrfs_free_space_header);
  66         btrfs_free_space_key(leaf, header, &disk_key);
  67         btrfs_disk_key_to_cpu(&location, &disk_key);
  68         btrfs_release_path(path);
  69
  70         inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
  71         if (!inode)
  72                 return ERR_PTR(-ENOENT);
  73         if (IS_ERR(inode))
  74                 return inode;
  75         if (is_bad_inode(inode)) {
  76                 iput(inode);
  77                 return ERR_PTR(-ENOENT);
  78         }
  79
  80         mapping_set_gfp_mask(inode->i_mapping,
  81                         mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
  82
  83         return inode;
  84 }
  85
  86 struct inode *lookup_free_space_inode(struct btrfs_root *root,
  87                                       struct btrfs_block_group_cache
  88                                       *block_group, struct btrfs_path *path)
  89 {
  90         struct inode *inode = NULL;
  91         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
  92
  93         spin_lock(&block_group->lock);
  94         if (block_group->inode)
  95                 inode = igrab(block_group->inode);
  96         spin_unlock(&block_group->lock);
  97         if (inode)
  98                 return inode;
  99
 100         inode = __lookup_free_space_inode(root, path,
 101                                           block_group->key.objectid);
 102         if (IS_ERR(inode))
 103                 return inode;
 104
 105         spin_lock(&block_group->lock);
 106         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 107                 btrfs_info(root->fs_info,
 108                         "Old style space inode found, converting.");
 109                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 110                         BTRFS_INODE_NODATACOW;
 111                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 112         }
 113
 114         if (!block_group->iref) {
 115                 block_group->inode = igrab(inode);
 116                 block_group->iref = 1;
 117         }
 118         spin_unlock(&block_group->lock);
 119
 120         return inode;
 121 }
 122
 123 static int __create_free_space_inode(struct btrfs_root *root,
 124                                      struct btrfs_trans_handle *trans,
 125                                      struct btrfs_path *path,
 126                                      u64 ino, u64 offset)
 127 {
 128         struct btrfs_key key;
 129         struct btrfs_disk_key disk_key;
 130         struct btrfs_free_space_header *header;
 131         struct btrfs_inode_item *inode_item;
 132         struct extent_buffer *leaf;
 133         u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 134         int ret;
 135
 136         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 137         if (ret)
 138                 return ret;
 139
 140         /* We inline crc's for the free disk space cache */
 141         if (ino != BTRFS_FREE_INO_OBJECTID)
 142                 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 143
 144         leaf = path->nodes[0];
 145         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 146                                     struct btrfs_inode_item);
 147         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 148         memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
 149                              sizeof(*inode_item));
 150         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 151         btrfs_set_inode_size(leaf, inode_item, 0);
 152         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 153         btrfs_set_inode_uid(leaf, inode_item, 0);
 154         btrfs_set_inode_gid(leaf, inode_item, 0);
 155         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 156         btrfs_set_inode_flags(leaf, inode_item, flags);
 157         btrfs_set_inode_nlink(leaf, inode_item, 1);
 158         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 159         btrfs_set_inode_block_group(leaf, inode_item, offset);
 160         btrfs_mark_buffer_dirty(leaf);
 161         btrfs_release_path(path);
 162
 163         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 164         key.offset = offset;
 165         key.type = 0;
 166
 167         ret = btrfs_insert_empty_item(trans, root, path, &key,
 168                                       sizeof(struct btrfs_free_space_header));
 169         if (ret < 0) {
 170                 btrfs_release_path(path);
 171                 return ret;
 172         }
 173         leaf = path->nodes[0];
 174         header = btrfs_item_ptr(leaf, path->slots[0],
 175                                 struct btrfs_free_space_header);
 176         memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
 177         btrfs_set_free_space_key(leaf, header, &disk_key);
 178         btrfs_mark_buffer_dirty(leaf);
 179         btrfs_release_path(path);
 180
 181         return 0;
 182 }
 183
 184 int create_free_space_inode(struct btrfs_root *root,
 185                             struct btrfs_trans_handle *trans,
 186                             struct btrfs_block_group_cache *block_group,
 187                             struct btrfs_path *path)
 188 {
 189         int ret;
 190         u64 ino;
 191
 192         ret = btrfs_find_free_objectid(root, &ino);
 193         if (ret < 0)
 194                 return ret;
 195
 196         return __create_free_space_inode(root, trans, path, ino,
 197                                          block_group->key.objectid);
 198 }
 199
 200 int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
 201                                        struct btrfs_block_rsv *rsv)
 202 {
 203         u64 needed_bytes;
 204         int ret;
 205
 206         /* 1 for slack space, 1 for updating the inode */
 207         needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
 208                 btrfs_calc_trans_metadata_size(root, 1);
 209
 210         spin_lock(&rsv->lock);
 211         if (rsv->reserved < needed_bytes)
 212                 ret = -ENOSPC;
 213         else
 214                 ret = 0;
 215         spin_unlock(&rsv->lock);
 216         return ret;
 217 }
 218
 219 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
 220                                     struct btrfs_trans_handle *trans,
 221                                     struct inode *inode)
 222 {
 223         int ret = 0;
 224
 225         btrfs_i_size_write(inode, 0);
 226         truncate_pagecache(inode, 0);
 227
 228         /*
 229          * We don't need an orphan item because truncating the free space cache
 230          * will never be split across transactions.
 231          */
 232         ret = btrfs_truncate_inode_items(trans, root, inode,
 233                                          0, BTRFS_EXTENT_DATA_KEY);
 234         if (ret) {
 235                 btrfs_abort_transaction(trans, root, ret);
 236                 return ret;
 237         }
 238
 239         ret = btrfs_update_inode(trans, root, inode);
 240         if (ret)
 241                 btrfs_abort_transaction(trans, root, ret);
 242
 243         return ret;
 244 }
 245
 246 static int readahead_cache(struct inode *inode)
 247 {
 248         struct file_ra_state *ra;
 249         unsigned long last_index;
 250
 251         ra = kzalloc(sizeof(*ra), GFP_NOFS);
 252         if (!ra)
 253                 return -ENOMEM;
 254
 255         file_ra_state_init(ra, inode->i_mapping);
 256         last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
 257
 258         page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 259
 260         kfree(ra);
 261
 262         return 0;
 263 }
 264
 265 struct io_ctl {
 266         void *cur, *orig;
 267         struct page *page;
 268         struct page **pages;
 269         struct btrfs_root *root;
 270         unsigned long size;
 271         int index;
 272         int num_pages;
 273         unsigned check_crcs:1;
 274 };
 275
 276 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
 277                        struct btrfs_root *root, int write)
 278 {
 279         int num_pages;
 280         int check_crcs = 0;
 281
 282         num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
 283                     PAGE_CACHE_SHIFT;
 284
 285         if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
 286                 check_crcs = 1;
 287
 288         /* Make sure we can fit our crcs into the first page */
 289         if (write && check_crcs &&
 290             (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
 291                 return -ENOSPC;
 292
 293         memset(io_ctl, 0, sizeof(struct io_ctl));
 294
 295         io_ctl->pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
 296         if (!io_ctl->pages)
 297                 return -ENOMEM;
 298
 299         io_ctl->num_pages = num_pages;
 300         io_ctl->root = root;
 301         io_ctl->check_crcs = check_crcs;
 302
 303         return 0;
 304 }
 305
 306 static void io_ctl_free(struct io_ctl *io_ctl)
 307 {
 308         kfree(io_ctl->pages);
 309 }
 310
 311 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
 312 {
 313         if (io_ctl->cur) {
 314                 kunmap(io_ctl->page);
 315                 io_ctl->cur = NULL;
 316                 io_ctl->orig = NULL;
 317         }
 318 }
 319
 320 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
 321 {
 322         ASSERT(io_ctl->index < io_ctl->num_pages);
 323         io_ctl->page = io_ctl->pages[io_ctl->index++];
 324         io_ctl->cur = kmap(io_ctl->page);
 325         io_ctl->orig = io_ctl->cur;
 326         io_ctl->size = PAGE_CACHE_SIZE;
 327         if (clear)
 328                 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
 329 }
 330
 331 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
 332 {
 333         int i;
 334
 335         io_ctl_unmap_page(io_ctl);
 336
 337         for (i = 0; i < io_ctl->num_pages; i++) {
 338                 if (io_ctl->pages[i]) {
 339                         ClearPageChecked(io_ctl->pages[i]);
 340                         unlock_page(io_ctl->pages[i]);
 341                         page_cache_release(io_ctl->pages[i]);
 342                 }
 343         }
 344 }
 345
 346 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
 347                                 int uptodate)
 348 {
 349         struct page *page;
 350         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 351         int i;
 352
 353         for (i = 0; i < io_ctl->num_pages; i++) {
 354                 page = find_or_create_page(inode->i_mapping, i, mask);
 355                 if (!page) {
 356                         io_ctl_drop_pages(io_ctl);
 357                         return -ENOMEM;
 358                 }
 359                 io_ctl->pages[i] = page;
 360                 if (uptodate && !PageUptodate(page)) {
 361                         btrfs_readpage(NULL, page);
 362                         lock_page(page);
 363                         if (!PageUptodate(page)) {
 364                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 365                                            "error reading free space cache");
 366                                 io_ctl_drop_pages(io_ctl);
 367                                 return -EIO;
 368                         }
 369                 }
 370         }
 371
 372         for (i = 0; i < io_ctl->num_pages; i++) {
 373                 clear_page_dirty_for_io(io_ctl->pages[i]);
 374                 set_page_extent_mapped(io_ctl->pages[i]);
 375         }
 376
 377         return 0;
 378 }
 379
 380 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
 381 {
 382         __le64 *val;
 383
 384         io_ctl_map_page(io_ctl, 1);
 385
 386         /*
 387          * Skip the csum areas.  If we don't check crcs then we just have a
 388          * 64bit chunk at the front of the first page.
 389          */
 390         if (io_ctl->check_crcs) {
 391                 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 392                 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 393         } else {
 394                 io_ctl->cur += sizeof(u64);
 395                 io_ctl->size -= sizeof(u64) * 2;
 396         }
 397
 398         val = io_ctl->cur;
 399         *val = cpu_to_le64(generation);
 400         io_ctl->cur += sizeof(u64);
 401 }
 402
 403 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
 404 {
 405         __le64 *gen;
 406
 407         /*
 408          * Skip the crc area.  If we don't check crcs then we just have a 64bit
 409          * chunk at the front of the first page.
 410          */
 411         if (io_ctl->check_crcs) {
 412                 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 413                 io_ctl->size -= sizeof(u64) +
 414                         (sizeof(u32) * io_ctl->num_pages);
 415         } else {
 416                 io_ctl->cur += sizeof(u64);
 417                 io_ctl->size -= sizeof(u64) * 2;
 418         }
 419
 420         gen = io_ctl->cur;
 421         if (le64_to_cpu(*gen) != generation) {
 422                 printk_ratelimited(KERN_ERR "BTRFS: space cache generation "
 423                                    "(%Lu) does not match inode (%Lu)\n", *gen,
 424                                    generation);
 425                 io_ctl_unmap_page(io_ctl);
 426                 return -EIO;
 427         }
 428         io_ctl->cur += sizeof(u64);
 429         return 0;
 430 }
 431
 432 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
 433 {
 434         u32 *tmp;
 435         u32 crc = ~(u32)0;
 436         unsigned offset = 0;
 437
 438         if (!io_ctl->check_crcs) {
 439                 io_ctl_unmap_page(io_ctl);
 440                 return;
 441         }
 442
 443         if (index == 0)
 444                 offset = sizeof(u32) * io_ctl->num_pages;
 445
 446         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 447                               PAGE_CACHE_SIZE - offset);
 448         btrfs_csum_final(crc, (char *)&crc);
 449         io_ctl_unmap_page(io_ctl);
 450         tmp = kmap(io_ctl->pages[0]);
 451         tmp += index;
 452         *tmp = crc;
 453         kunmap(io_ctl->pages[0]);
 454 }
 455
 456 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
 457 {
 458         u32 *tmp, val;
 459         u32 crc = ~(u32)0;
 460         unsigned offset = 0;
 461
 462         if (!io_ctl->check_crcs) {
 463                 io_ctl_map_page(io_ctl, 0);
 464                 return 0;
 465         }
 466
 467         if (index == 0)
 468                 offset = sizeof(u32) * io_ctl->num_pages;
 469
 470         tmp = kmap(io_ctl->pages[0]);
 471         tmp += index;
 472         val = *tmp;
 473         kunmap(io_ctl->pages[0]);
 474
 475         io_ctl_map_page(io_ctl, 0);
 476         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 477                               PAGE_CACHE_SIZE - offset);
 478         btrfs_csum_final(crc, (char *)&crc);
 479         if (val != crc) {
 480                 printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free "
 481                                    "space cache\n");
 482                 io_ctl_unmap_page(io_ctl);
 483                 return -EIO;
 484         }
 485
 486         return 0;
 487 }
 488
 489 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
 490                             void *bitmap)
 491 {
 492         struct btrfs_free_space_entry *entry;
 493
 494         if (!io_ctl->cur)
 495                 return -ENOSPC;
 496
 497         entry = io_ctl->cur;
 498         entry->offset = cpu_to_le64(offset);
 499         entry->bytes = cpu_to_le64(bytes);
 500         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 501                 BTRFS_FREE_SPACE_EXTENT;
 502         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 503         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 504
 505         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 506                 return 0;
 507
 508         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 509
 510         /* No more pages to map */
 511         if (io_ctl->index >= io_ctl->num_pages)
 512                 return 0;
 513
 514         /* map the next page */
 515         io_ctl_map_page(io_ctl, 1);
 516         return 0;
 517 }
 518
 519 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
 520 {
 521         if (!io_ctl->cur)
 522                 return -ENOSPC;
 523
 524         /*
 525          * If we aren't at the start of the current page, unmap this one and
 526          * map the next one if there is any left.
 527          */
 528         if (io_ctl->cur != io_ctl->orig) {
 529                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 530                 if (io_ctl->index >= io_ctl->num_pages)
 531                         return -ENOSPC;
 532                 io_ctl_map_page(io_ctl, 0);
 533         }
 534
 535         memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
 536         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 537         if (io_ctl->index < io_ctl->num_pages)
 538                 io_ctl_map_page(io_ctl, 0);
 539         return 0;
 540 }
 541
 542 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
 543 {
 544         /*
 545          * If we're not on the boundary we know we've modified the page and we
 546          * need to crc the page.
 547          */
 548         if (io_ctl->cur != io_ctl->orig)
 549                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 550         else
 551                 io_ctl_unmap_page(io_ctl);
 552
 553         while (io_ctl->index < io_ctl->num_pages) {
 554                 io_ctl_map_page(io_ctl, 1);
 555                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 556         }
 557 }
 558
 559 static int io_ctl_read_entry(struct io_ctl *io_ctl,
 560                             struct btrfs_free_space *entry, u8 *type)
 561 {
 562         struct btrfs_free_space_entry *e;
 563         int ret;
 564
 565         if (!io_ctl->cur) {
 566                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 567                 if (ret)
 568                         return ret;
 569         }
 570
 571         e = io_ctl->cur;
 572         entry->offset = le64_to_cpu(e->offset);
 573         entry->bytes = le64_to_cpu(e->bytes);
 574         *type = e->type;
 575         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 576         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 577
 578         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 579                 return 0;
 580
 581         io_ctl_unmap_page(io_ctl);
 582
 583         return 0;
 584 }
 585
 586 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
 587                               struct btrfs_free_space *entry)
 588 {
 589         int ret;
 590
 591         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 592         if (ret)
 593                 return ret;
 594
 595         memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
 596         io_ctl_unmap_page(io_ctl);
 597
 598         return 0;
 599 }
 600
 601 /*
 602  * Since we attach pinned extents after the fact we can have contiguous sections
 603  * of free space that are split up in entries.  This poses a problem with the
 604  * tree logging stuff since it could have allocated across what appears to be 2
 605  * entries since we would have merged the entries when adding the pinned extents
 606  * back to the free space cache.  So run through the space cache that we just
 607  * loaded and merge contiguous entries.  This will make the log replay stuff not
 608  * blow up and it will make for nicer allocator behavior.
 609  */
 610 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
 611 {
 612         struct btrfs_free_space *e, *prev = NULL;
 613         struct rb_node *n;
 614
 615 again:
 616         spin_lock(&ctl->tree_lock);
 617         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 618                 e = rb_entry(n, struct btrfs_free_space, offset_index);
 619                 if (!prev)
 620                         goto next;
 621                 if (e->bitmap || prev->bitmap)
 622                         goto next;
 623                 if (prev->offset + prev->bytes == e->offset) {
 624                         unlink_free_space(ctl, prev);
 625                         unlink_free_space(ctl, e);
 626                         prev->bytes += e->bytes;
 627                         kmem_cache_free(btrfs_free_space_cachep, e);
 628                         link_free_space(ctl, prev);
 629                         prev = NULL;
 630                         spin_unlock(&ctl->tree_lock);
 631                         goto again;
 632                 }
 633 next:
 634                 prev = e;
 635         }
 636         spin_unlock(&ctl->tree_lock);
 637 }
 638
 639 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 640                                    struct btrfs_free_space_ctl *ctl,
 641                                    struct btrfs_path *path, u64 offset)
 642 {
 643         struct btrfs_free_space_header *header;
 644         struct extent_buffer *leaf;
 645         struct io_ctl io_ctl;
 646         struct btrfs_key key;
 647         struct btrfs_free_space *e, *n;
 648         struct list_head bitmaps;
 649         u64 num_entries;
 650         u64 num_bitmaps;
 651         u64 generation;
 652         u8 type;
 653         int ret = 0;
 654
 655         INIT_LIST_HEAD(&bitmaps);
 656
 657         /* Nothing in the space cache, goodbye */
 658         if (!i_size_read(inode))
 659                 return 0;
 660
 661         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 662         key.offset = offset;
 663         key.type = 0;
 664
 665         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 666         if (ret < 0)
 667                 return 0;
 668         else if (ret > 0) {
 669                 btrfs_release_path(path);
 670                 return 0;
 671         }
 672
 673         ret = -1;
 674
 675         leaf = path->nodes[0];
 676         header = btrfs_item_ptr(leaf, path->slots[0],
 677                                 struct btrfs_free_space_header);
 678         num_entries = btrfs_free_space_entries(leaf, header);
 679         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 680         generation = btrfs_free_space_generation(leaf, header);
 681         btrfs_release_path(path);
 682
 683         if (BTRFS_I(inode)->generation != generation) {
 684                 btrfs_err(root->fs_info,
 685                         "free space inode generation (%llu) "
 686                         "did not match free space cache generation (%llu)",
 687                         BTRFS_I(inode)->generation, generation);
 688                 return 0;
 689         }
 690
 691         if (!num_entries)
 692                 return 0;
 693
 694         ret = io_ctl_init(&io_ctl, inode, root, 0);
 695         if (ret)
 696                 return ret;
 697
 698         ret = readahead_cache(inode);
 699         if (ret)
 700                 goto out;
 701
 702         ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
 703         if (ret)
 704                 goto out;
 705
 706         ret = io_ctl_check_crc(&io_ctl, 0);
 707         if (ret)
 708                 goto free_cache;
 709
 710         ret = io_ctl_check_generation(&io_ctl, generation);
 711         if (ret)
 712                 goto free_cache;
 713
 714         while (num_entries) {
 715                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
 716                                       GFP_NOFS);
 717                 if (!e)
 718                         goto free_cache;
 719
 720                 ret = io_ctl_read_entry(&io_ctl, e, &type);
 721                 if (ret) {
 722                         kmem_cache_free(btrfs_free_space_cachep, e);
 723                         goto free_cache;
 724                 }
 725
 726                 if (!e->bytes) {
 727                         kmem_cache_free(btrfs_free_space_cachep, e);
 728                         goto free_cache;
 729                 }
 730
 731                 if (type == BTRFS_FREE_SPACE_EXTENT) {
 732                         spin_lock(&ctl->tree_lock);
 733                         ret = link_free_space(ctl, e);
 734                         spin_unlock(&ctl->tree_lock);
 735                         if (ret) {
 736                                 btrfs_err(root->fs_info,
 737                                         "Duplicate entries in free space cache, dumping");
 738                                 kmem_cache_free(btrfs_free_space_cachep, e);
 739                                 goto free_cache;
 740                         }
 741                 } else {
 742                         ASSERT(num_bitmaps);
 743                         num_bitmaps--;
 744                         e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 745                         if (!e->bitmap) {
 746                                 kmem_cache_free(
 747                                         btrfs_free_space_cachep, e);
 748                                 goto free_cache;
 749                         }
 750                         spin_lock(&ctl->tree_lock);
 751                         ret = link_free_space(ctl, e);
 752                         ctl->total_bitmaps++;
 753                         ctl->op->recalc_thresholds(ctl);
 754                         spin_unlock(&ctl->tree_lock);
 755                         if (ret) {
 756                                 btrfs_err(root->fs_info,
 757                                         "Duplicate entries in free space cache, dumping");
 758                                 kmem_cache_free(btrfs_free_space_cachep, e);
 759                                 goto free_cache;
 760                         }
 761                         list_add_tail(&e->list, &bitmaps);
 762                 }
 763
 764                 num_entries--;
 765         }
 766
 767         io_ctl_unmap_page(&io_ctl);
 768
 769         /*
 770          * We add the bitmaps at the end of the entries in order that
 771          * the bitmap entries are added to the cache.
 772          */
 773         list_for_each_entry_safe(e, n, &bitmaps, list) {
 774                 list_del_init(&e->list);
 775                 ret = io_ctl_read_bitmap(&io_ctl, e);
 776                 if (ret)
 777                         goto free_cache;
 778         }
 779
 780         io_ctl_drop_pages(&io_ctl);
 781         merge_space_tree(ctl);
 782         ret = 1;
 783 out:
 784         io_ctl_free(&io_ctl);
 785         return ret;
 786 free_cache:
 787         io_ctl_drop_pages(&io_ctl);
 788         __btrfs_remove_free_space_cache(ctl);
 789         goto out;
 790 }
 791
 792 int load_free_space_cache(struct btrfs_fs_info *fs_info,
 793                           struct btrfs_block_group_cache *block_group)
 794 {
 795         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 796         struct btrfs_root *root = fs_info->tree_root;
 797         struct inode *inode;
 798         struct btrfs_path *path;
 799         int ret = 0;
 800         bool matched;
 801         u64 used = btrfs_block_group_used(&block_group->item);
 802
 803         /*
 804          * If this block group has been marked to be cleared for one reason or
 805          * another then we can't trust the on disk cache, so just return.
 806          */
 807         spin_lock(&block_group->lock);
 808         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 809                 spin_unlock(&block_group->lock);
 810                 return 0;
 811         }
 812         spin_unlock(&block_group->lock);
 813
 814         path = btrfs_alloc_path();
 815         if (!path)
 816                 return 0;
 817         path->search_commit_root = 1;
 818         path->skip_locking = 1;
 819
 820         inode = lookup_free_space_inode(root, block_group, path);
 821         if (IS_ERR(inode)) {
 822                 btrfs_free_path(path);
 823                 return 0;
 824         }
 825
 826         /* We may have converted the inode and made the cache invalid. */
 827         spin_lock(&block_group->lock);
 828         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 829                 spin_unlock(&block_group->lock);
 830                 btrfs_free_path(path);
 831                 goto out;
 832         }
 833         spin_unlock(&block_group->lock);
 834
 835         ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 836                                       path, block_group->key.objectid);
 837         btrfs_free_path(path);
 838         if (ret <= 0)
 839                 goto out;
 840
 841         spin_lock(&ctl->tree_lock);
 842         matched = (ctl->free_space == (block_group->key.offset - used -
 843                                        block_group->bytes_super));
 844         spin_unlock(&ctl->tree_lock);
 845
 846         if (!matched) {
 847                 __btrfs_remove_free_space_cache(ctl);
 848                 btrfs_warn(fs_info, "block group %llu has wrong amount of free space",
 849                         block_group->key.objectid);
 850                 ret = -1;
 851         }
 852 out:
 853         if (ret < 0) {
 854                 /* This cache is bogus, make sure it gets cleared */
 855                 spin_lock(&block_group->lock);
 856                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 857                 spin_unlock(&block_group->lock);
 858                 ret = 0;
 859
 860                 btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now",
 861                         block_group->key.objectid);
 862         }
 863
 864         iput(inode);
 865         return ret;
 866 }
 867
 868 static noinline_for_stack
 869 int write_cache_extent_entries(struct io_ctl *io_ctl,
 870                               struct btrfs_free_space_ctl *ctl,
 871                               struct btrfs_block_group_cache *block_group,
 872                               int *entries, int *bitmaps,
 873                               struct list_head *bitmap_list)
 874 {
 875         int ret;
 876         struct btrfs_free_cluster *cluster = NULL;
 877         struct rb_node *node = rb_first(&ctl->free_space_offset);
 878
 879         /* Get the cluster for this block_group if it exists */
 880         if (block_group && !list_empty(&block_group->cluster_list)) {
 881                 cluster = list_entry(block_group->cluster_list.next,
 882                                      struct btrfs_free_cluster,
 883                                      block_group_list);
 884         }
 885
 886         if (!node && cluster) {
 887                 node = rb_first(&cluster->root);
 888                 cluster = NULL;
 889         }
 890
 891         /* Write out the extent entries */
 892         while (node) {
 893                 struct btrfs_free_space *e;
 894
 895                 e = rb_entry(node, struct btrfs_free_space, offset_index);
 896                 *entries += 1;
 897
 898                 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
 899                                        e->bitmap);
 900                 if (ret)
 901                         goto fail;
 902
 903                 if (e->bitmap) {
 904                         list_add_tail(&e->list, bitmap_list);
 905                         *bitmaps += 1;
 906                 }
 907                 node = rb_next(node);
 908                 if (!node && cluster) {
 909                         node = rb_first(&cluster->root);
 910                         cluster = NULL;
 911                 }
 912         }
 913         return 0;
 914 fail:
 915         return -ENOSPC;
 916 }
 917
 918 static noinline_for_stack int
 919 update_cache_item(struct btrfs_trans_handle *trans,
 920                   struct btrfs_root *root,
 921                   struct inode *inode,
 922                   struct btrfs_path *path, u64 offset,
 923                   int entries, int bitmaps)
 924 {
 925         struct btrfs_key key;
 926         struct btrfs_free_space_header *header;
 927         struct extent_buffer *leaf;
 928         int ret;
 929
 930         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 931         key.offset = offset;
 932         key.type = 0;
 933
 934         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 935         if (ret < 0) {
 936                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
 937                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
 938                                  GFP_NOFS);
 939                 goto fail;
 940         }
 941         leaf = path->nodes[0];
 942         if (ret > 0) {
 943                 struct btrfs_key found_key;
 944                 ASSERT(path->slots[0]);
 945                 path->slots[0]--;
 946                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 947                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
 948                     found_key.offset != offset) {
 949                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
 950                                          inode->i_size - 1,
 951                                          EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
 952                                          NULL, GFP_NOFS);
 953                         btrfs_release_path(path);
 954                         goto fail;
 955                 }
 956         }
 957
 958         BTRFS_I(inode)->generation = trans->transid;
 959         header = btrfs_item_ptr(leaf, path->slots[0],
 960                                 struct btrfs_free_space_header);
 961         btrfs_set_free_space_entries(leaf, header, entries);
 962         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
 963         btrfs_set_free_space_generation(leaf, header, trans->transid);
 964         btrfs_mark_buffer_dirty(leaf);
 965         btrfs_release_path(path);
 966
 967         return 0;
 968
 969 fail:
 970         return -1;
 971 }
 972
 973 static noinline_for_stack int
 974 write_pinned_extent_entries(struct btrfs_root *root,
 975                             struct btrfs_block_group_cache *block_group,
 976                             struct io_ctl *io_ctl,
 977                             int *entries)
 978 {
 979         u64 start, extent_start, extent_end, len;
 980         struct extent_io_tree *unpin = NULL;
 981         int ret;
 982
 983         if (!block_group)
 984                 return 0;
 985
 986         /*
 987          * We want to add any pinned extents to our free space cache
 988          * so we don't leak the space
 989          *
 990          * We shouldn't have switched the pinned extents yet so this is the
 991          * right one
 992          */
 993         unpin = root->fs_info->pinned_extents;
 994
 995         start = block_group->key.objectid;
 996
 997         while (start < block_group->key.objectid + block_group->key.offset) {
 998                 ret = find_first_extent_bit(unpin, start,
 999                                             &extent_start, &extent_end,
1000                                             EXTENT_DIRTY, NULL);
1001                 if (ret)
1002                         return 0;
1003
1004                 /* This pinned extent is out of our range */
1005                 if (extent_start >= block_group->key.objectid +
1006                     block_group->key.offset)
1007                         return 0;
1008
1009                 extent_start = max(extent_start, start);
1010                 extent_end = min(block_group->key.objectid +
1011                                  block_group->key.offset, extent_end + 1);
1012                 len = extent_end - extent_start;
1013
1014                 *entries += 1;
1015                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1016                 if (ret)
1017                         return -ENOSPC;
1018
1019                 start = extent_end;
1020         }
1021
1022         return 0;
1023 }
1024
1025 static noinline_for_stack int
1026 write_bitmap_entries(struct io_ctl *io_ctl, struct list_head *bitmap_list)
1027 {
1028         struct list_head *pos, *n;
1029         int ret;
1030
1031         /* Write out the bitmaps */
1032         list_for_each_safe(pos, n, bitmap_list) {
1033                 struct btrfs_free_space *entry =
1034                         list_entry(pos, struct btrfs_free_space, list);
1035
1036                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1037                 if (ret)
1038                         return -ENOSPC;
1039                 list_del_init(&entry->list);
1040         }
1041
1042         return 0;
1043 }
1044
1045 static int flush_dirty_cache(struct inode *inode)
1046 {
1047         int ret;
1048
1049         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1050         if (ret)
1051                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1052                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1053                                  GFP_NOFS);
1054
1055         return ret;
1056 }
1057
1058 static void noinline_for_stack
1059 cleanup_write_cache_enospc(struct inode *inode,
1060                            struct io_ctl *io_ctl,
1061                            struct extent_state **cached_state,
1062                            struct list_head *bitmap_list)
1063 {
1064         struct list_head *pos, *n;
1065
1066         list_for_each_safe(pos, n, bitmap_list) {
1067                 struct btrfs_free_space *entry =
1068                         list_entry(pos, struct btrfs_free_space, list);
1069                 list_del_init(&entry->list);
1070         }
1071         io_ctl_drop_pages(io_ctl);
1072         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1073                              i_size_read(inode) - 1, cached_state,
1074                              GFP_NOFS);
1075 }
1076
1077 /**
1078  * __btrfs_write_out_cache - write out cached info to an inode
1079  * @root - the root the inode belongs to
1080  * @ctl - the free space cache we are going to write out
1081  * @block_group - the block_group for this cache if it belongs to a block_group
1082  * @trans - the trans handle
1083  * @path - the path to use
1084  * @offset - the offset for the key we'll insert
1085  *
1086  * This function writes out a free space cache struct to disk for quick recovery
1087  * on mount.  This will return 0 if it was successfull in writing the cache out,
1088  * and -1 if it was not.
1089  */
1090 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1091                                    struct btrfs_free_space_ctl *ctl,
1092                                    struct btrfs_block_group_cache *block_group,
1093                                    struct btrfs_trans_handle *trans,
1094                                    struct btrfs_path *path, u64 offset)
1095 {
1096         struct extent_state *cached_state = NULL;
1097         struct io_ctl io_ctl;
1098         LIST_HEAD(bitmap_list);
1099         int entries = 0;
1100         int bitmaps = 0;
1101         int ret;
1102
1103         if (!i_size_read(inode))
1104                 return -1;
1105
1106         ret = io_ctl_init(&io_ctl, inode, root, 1);
1107         if (ret)
1108                 return -1;
1109
1110         /* Lock all pages first so we can lock the extent safely. */
1111         io_ctl_prepare_pages(&io_ctl, inode, 0);
1112
1113         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1114                          0, &cached_state);
1115
1116         io_ctl_set_generation(&io_ctl, trans->transid);
1117
1118         /* Write out the extent entries in the free space cache */
1119         ret = write_cache_extent_entries(&io_ctl, ctl,
1120                                          block_group, &entries, &bitmaps,
1121                                          &bitmap_list);
1122         if (ret)
1123                 goto out_nospc;
1124
1125         /*
1126          * Some spaces that are freed in the current transaction are pinned,
1127          * they will be added into free space cache after the transaction is
1128          * committed, we shouldn't lose them.
1129          */
1130         ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
1131         if (ret)
1132                 goto out_nospc;
1133
1134         /* At last, we write out all the bitmaps. */
1135         ret = write_bitmap_entries(&io_ctl, &bitmap_list);
1136         if (ret)
1137                 goto out_nospc;
1138
1139         /* Zero out the rest of the pages just to make sure */
1140         io_ctl_zero_remaining_pages(&io_ctl);
1141
1142         /* Everything is written out, now we dirty the pages in the file. */
1143         ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1144                                 0, i_size_read(inode), &cached_state);
1145         if (ret)
1146                 goto out_nospc;
1147
1148         /*
1149          * Release the pages and unlock the extent, we will flush
1150          * them out later
1151          */
1152         io_ctl_drop_pages(&io_ctl);
1153
1154         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1155                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1156
1157         /* Flush the dirty pages in the cache file. */
1158         ret = flush_dirty_cache(inode);
1159         if (ret)
1160                 goto out;
1161
1162         /* Update the cache item to tell everyone this cache file is valid. */
1163         ret = update_cache_item(trans, root, inode, path, offset,
1164                                 entries, bitmaps);
1165 out:
1166         io_ctl_free(&io_ctl);
1167         if (ret) {
1168                 invalidate_inode_pages2(inode->i_mapping);
1169                 BTRFS_I(inode)->generation = 0;
1170         }
1171         btrfs_update_inode(trans, root, inode);
1172         return ret;
1173
1174 out_nospc:
1175         cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list);
1176         goto out;
1177 }
1178
1179 int btrfs_write_out_cache(struct btrfs_root *root,
1180                           struct btrfs_trans_handle *trans,
1181                           struct btrfs_block_group_cache *block_group,
1182                           struct btrfs_path *path)
1183 {
1184         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1185         struct inode *inode;
1186         int ret = 0;
1187
1188         root = root->fs_info->tree_root;
1189
1190         spin_lock(&block_group->lock);
1191         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1192                 spin_unlock(&block_group->lock);
1193                 return 0;
1194         }
1195         spin_unlock(&block_group->lock);
1196
1197         inode = lookup_free_space_inode(root, block_group, path);
1198         if (IS_ERR(inode))
1199                 return 0;
1200
1201         ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1202                                       path, block_group->key.objectid);
1203         if (ret) {
1204                 spin_lock(&block_group->lock);
1205                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1206                 spin_unlock(&block_group->lock);
1207                 ret = 0;
1208 #ifdef DEBUG
1209                 btrfs_err(root->fs_info,
1210                         "failed to write free space cache for block group %llu",
1211                         block_group->key.objectid);
1212 #endif
1213         }
1214
1215         iput(inode);
1216         return ret;
1217 }
1218
1219 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1220                                           u64 offset)
1221 {
1222         ASSERT(offset >= bitmap_start);
1223         offset -= bitmap_start;
1224         return (unsigned long)(div_u64(offset, unit));
1225 }
1226
1227 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1228 {
1229         return (unsigned long)(div_u64(bytes, unit));
1230 }
1231
1232 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1233                                    u64 offset)
1234 {
1235         u64 bitmap_start;
1236         u64 bytes_per_bitmap;
1237
1238         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1239         bitmap_start = offset - ctl->start;
1240         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1241         bitmap_start *= bytes_per_bitmap;
1242         bitmap_start += ctl->start;
1243
1244         return bitmap_start;
1245 }
1246
1247 static int tree_insert_offset(struct rb_root *root, u64 offset,
1248                               struct rb_node *node, int bitmap)
1249 {
1250         struct rb_node **p = &root->rb_node;
1251         struct rb_node *parent = NULL;
1252         struct btrfs_free_space *info;
1253
1254         while (*p) {
1255                 parent = *p;
1256                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1257
1258                 if (offset < info->offset) {
1259                         p = &(*p)->rb_left;
1260                 } else if (offset > info->offset) {
1261                         p = &(*p)->rb_right;
1262                 } else {
1263                         /*
1264                          * we could have a bitmap entry and an extent entry
1265                          * share the same offset.  If this is the case, we want
1266                          * the extent entry to always be found first if we do a
1267                          * linear search through the tree, since we want to have
1268                          * the quickest allocation time, and allocating from an
1269                          * extent is faster than allocating from a bitmap.  So
1270                          * if we're inserting a bitmap and we find an entry at
1271                          * this offset, we want to go right, or after this entry
1272                          * logically.  If we are inserting an extent and we've
1273                          * found a bitmap, we want to go left, or before
1274                          * logically.
1275                          */
1276                         if (bitmap) {
1277                                 if (info->bitmap) {
1278                                         WARN_ON_ONCE(1);
1279                                         return -EEXIST;
1280                                 }
1281                                 p = &(*p)->rb_right;
1282                         } else {
1283                                 if (!info->bitmap) {
1284                                         WARN_ON_ONCE(1);
1285                                         return -EEXIST;
1286                                 }
1287                                 p = &(*p)->rb_left;
1288                         }
1289                 }
1290         }
1291
1292         rb_link_node(node, parent, p);
1293         rb_insert_color(node, root);
1294
1295         return 0;
1296 }
1297
1298 /*
1299  * searches the tree for the given offset.
1300  *
1301  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1302  * want a section that has at least bytes size and comes at or after the given
1303  * offset.
1304  */
1305 static struct btrfs_free_space *
1306 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1307                    u64 offset, int bitmap_only, int fuzzy)
1308 {
1309         struct rb_node *n = ctl->free_space_offset.rb_node;
1310         struct btrfs_free_space *entry, *prev = NULL;
1311
1312         /* find entry that is closest to the 'offset' */
1313         while (1) {
1314                 if (!n) {
1315                         entry = NULL;
1316                         break;
1317                 }
1318
1319                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1320                 prev = entry;
1321
1322                 if (offset < entry->offset)
1323                         n = n->rb_left;
1324                 else if (offset > entry->offset)
1325                         n = n->rb_right;
1326                 else
1327                         break;
1328         }
1329
1330         if (bitmap_only) {
1331                 if (!entry)
1332                         return NULL;
1333                 if (entry->bitmap)
1334                         return entry;
1335
1336                 /*
1337                  * bitmap entry and extent entry may share same offset,
1338                  * in that case, bitmap entry comes after extent entry.
1339                  */
1340                 n = rb_next(n);
1341                 if (!n)
1342                         return NULL;
1343                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1344                 if (entry->offset != offset)
1345                         return NULL;
1346
1347                 WARN_ON(!entry->bitmap);
1348                 return entry;
1349         } else if (entry) {
1350                 if (entry->bitmap) {
1351                         /*
1352                          * if previous extent entry covers the offset,
1353                          * we should return it instead of the bitmap entry
1354                          */
1355                         n = rb_prev(&entry->offset_index);
1356                         if (n) {
1357                                 prev = rb_entry(n, struct btrfs_free_space,
1358                                                 offset_index);
1359                                 if (!prev->bitmap &&
1360                                     prev->offset + prev->bytes > offset)
1361                                         entry = prev;
1362                         }
1363                 }
1364                 return entry;
1365         }
1366
1367         if (!prev)
1368                 return NULL;
1369
1370         /* find last entry before the 'offset' */
1371         entry = prev;
1372         if (entry->offset > offset) {
1373                 n = rb_prev(&entry->offset_index);
1374                 if (n) {
1375                         entry = rb_entry(n, struct btrfs_free_space,
1376                                         offset_index);
1377                         ASSERT(entry->offset <= offset);
1378                 } else {
1379                         if (fuzzy)
1380                                 return entry;
1381                         else
1382                                 return NULL;
1383                 }
1384         }
1385
1386         if (entry->bitmap) {
1387                 n = rb_prev(&entry->offset_index);
1388                 if (n) {
1389                         prev = rb_entry(n, struct btrfs_free_space,
1390                                         offset_index);
1391                         if (!prev->bitmap &&
1392                             prev->offset + prev->bytes > offset)
1393                                 return prev;
1394                 }
1395                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1396                         return entry;
1397         } else if (entry->offset + entry->bytes > offset)
1398                 return entry;
1399
1400         if (!fuzzy)
1401                 return NULL;
1402
1403         while (1) {
1404                 if (entry->bitmap) {
1405                         if (entry->offset + BITS_PER_BITMAP *
1406                             ctl->unit > offset)
1407                                 break;
1408                 } else {
1409                         if (entry->offset + entry->bytes > offset)
1410                                 break;
1411                 }
1412
1413                 n = rb_next(&entry->offset_index);
1414                 if (!n)
1415                         return NULL;
1416                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1417         }
1418         return entry;
1419 }
1420
1421 static inline void
1422 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1423                     struct btrfs_free_space *info)
1424 {
1425         rb_erase(&info->offset_index, &ctl->free_space_offset);
1426         ctl->free_extents--;
1427 }
1428
1429 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1430                               struct btrfs_free_space *info)
1431 {
1432         __unlink_free_space(ctl, info);
1433         ctl->free_space -= info->bytes;
1434 }
1435
1436 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1437                            struct btrfs_free_space *info)
1438 {
1439         int ret = 0;
1440
1441         ASSERT(info->bytes || info->bitmap);
1442         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1443                                  &info->offset_index, (info->bitmap != NULL));
1444         if (ret)
1445                 return ret;
1446
1447         ctl->free_space += info->bytes;
1448         ctl->free_extents++;
1449         return ret;
1450 }
1451
1452 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1453 {
1454         struct btrfs_block_group_cache *block_group = ctl->private;
1455         u64 max_bytes;
1456         u64 bitmap_bytes;
1457         u64 extent_bytes;
1458         u64 size = block_group->key.offset;
1459         u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1460         int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1461
1462         max_bitmaps = max(max_bitmaps, 1);
1463
1464         ASSERT(ctl->total_bitmaps <= max_bitmaps);
1465
1466         /*
1467          * The goal is to keep the total amount of memory used per 1gb of space
1468          * at or below 32k, so we need to adjust how much memory we allow to be
1469          * used by extent based free space tracking
1470          */
1471         if (size < 1024 * 1024 * 1024)
1472                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1473         else
1474                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1475                         div64_u64(size, 1024 * 1024 * 1024);
1476
1477         /*
1478          * we want to account for 1 more bitmap than what we have so we can make
1479          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1480          * we add more bitmaps.
1481          */
1482         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1483
1484         if (bitmap_bytes >= max_bytes) {
1485                 ctl->extents_thresh = 0;
1486                 return;
1487         }
1488
1489         /*
1490          * we want the extent entry threshold to always be at most 1/2 the maxw
1491          * bytes we can have, or whatever is less than that.
1492          */
1493         extent_bytes = max_bytes - bitmap_bytes;
1494         extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1495
1496         ctl->extents_thresh =
1497                 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1498 }
1499
1500 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1501                                        struct btrfs_free_space *info,
1502                                        u64 offset, u64 bytes)
1503 {
1504         unsigned long start, count;
1505
1506         start = offset_to_bit(info->offset, ctl->unit, offset);
1507         count = bytes_to_bits(bytes, ctl->unit);
1508         ASSERT(start + count <= BITS_PER_BITMAP);
1509
1510         bitmap_clear(info->bitmap, start, count);
1511
1512         info->bytes -= bytes;
1513 }
1514
1515 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1516                               struct btrfs_free_space *info, u64 offset,
1517                               u64 bytes)
1518 {
1519         __bitmap_clear_bits(ctl, info, offset, bytes);
1520         ctl->free_space -= bytes;
1521 }
1522
1523 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1524                             struct btrfs_free_space *info, u64 offset,
1525                             u64 bytes)
1526 {
1527         unsigned long start, count;
1528
1529         start = offset_to_bit(info->offset, ctl->unit, offset);
1530         count = bytes_to_bits(bytes, ctl->unit);
1531         ASSERT(start + count <= BITS_PER_BITMAP);
1532
1533         bitmap_set(info->bitmap, start, count);
1534
1535         info->bytes += bytes;
1536         ctl->free_space += bytes;
1537 }
1538
1539 /*
1540  * If we can not find suitable extent, we will use bytes to record
1541  * the size of the max extent.
1542  */
1543 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1544                          struct btrfs_free_space *bitmap_info, u64 *offset,
1545                          u64 *bytes)
1546 {
1547         unsigned long found_bits = 0;
1548         unsigned long max_bits = 0;
1549         unsigned long bits, i;
1550         unsigned long next_zero;
1551         unsigned long extent_bits;
1552
1553         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1554                           max_t(u64, *offset, bitmap_info->offset));
1555         bits = bytes_to_bits(*bytes, ctl->unit);
1556
1557         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1558                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1559                                                BITS_PER_BITMAP, i);
1560                 extent_bits = next_zero - i;
1561                 if (extent_bits >= bits) {
1562                         found_bits = extent_bits;
1563                         break;
1564                 } else if (extent_bits > max_bits) {
1565                         max_bits = extent_bits;
1566                 }
1567                 i = next_zero;
1568         }
1569
1570         if (found_bits) {
1571                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1572                 *bytes = (u64)(found_bits) * ctl->unit;
1573                 return 0;
1574         }
1575
1576         *bytes = (u64)(max_bits) * ctl->unit;
1577         return -1;
1578 }
1579
1580 /* Cache the size of the max extent in bytes */
1581 static struct btrfs_free_space *
1582 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1583                 unsigned long align, u64 *max_extent_size)
1584 {
1585         struct btrfs_free_space *entry;
1586         struct rb_node *node;
1587         u64 tmp;
1588         u64 align_off;
1589         int ret;
1590
1591         if (!ctl->free_space_offset.rb_node)
1592                 goto out;
1593
1594         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1595         if (!entry)
1596                 goto out;
1597
1598         for (node = &entry->offset_index; node; node = rb_next(node)) {
1599                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1600                 if (entry->bytes < *bytes) {
1601                         if (entry->bytes > *max_extent_size)
1602                                 *max_extent_size = entry->bytes;
1603                         continue;
1604                 }
1605
1606                 /* make sure the space returned is big enough
1607                  * to match our requested alignment
1608                  */
1609                 if (*bytes >= align) {
1610                         tmp = entry->offset - ctl->start + align - 1;
1611                         do_div(tmp, align);
1612                         tmp = tmp * align + ctl->start;
1613                         align_off = tmp - entry->offset;
1614                 } else {
1615                         align_off = 0;
1616                         tmp = entry->offset;
1617                 }
1618
1619                 if (entry->bytes < *bytes + align_off) {
1620                         if (entry->bytes > *max_extent_size)
1621                                 *max_extent_size = entry->bytes;
1622                         continue;
1623                 }
1624
1625                 if (entry->bitmap) {
1626                         u64 size = *bytes;
1627
1628                         ret = search_bitmap(ctl, entry, &tmp, &size);
1629                         if (!ret) {
1630                                 *offset = tmp;
1631                                 *bytes = size;
1632                                 return entry;
1633                         } else if (size > *max_extent_size) {
1634                                 *max_extent_size = size;
1635                         }
1636                         continue;
1637                 }
1638
1639                 *offset = tmp;
1640                 *bytes = entry->bytes - align_off;
1641                 return entry;
1642         }
1643 out:
1644         return NULL;
1645 }
1646
1647 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1648                            struct btrfs_free_space *info, u64 offset)
1649 {
1650         info->offset = offset_to_bitmap(ctl, offset);
1651         info->bytes = 0;
1652         INIT_LIST_HEAD(&info->list);
1653         link_free_space(ctl, info);
1654         ctl->total_bitmaps++;
1655
1656         ctl->op->recalc_thresholds(ctl);
1657 }
1658
1659 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1660                         struct btrfs_free_space *bitmap_info)
1661 {
1662         unlink_free_space(ctl, bitmap_info);
1663         kfree(bitmap_info->bitmap);
1664         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1665         ctl->total_bitmaps--;
1666         ctl->op->recalc_thresholds(ctl);
1667 }
1668
1669 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1670                               struct btrfs_free_space *bitmap_info,
1671                               u64 *offset, u64 *bytes)
1672 {
1673         u64 end;
1674         u64 search_start, search_bytes;
1675         int ret;
1676
1677 again:
1678         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1679
1680         /*
1681          * We need to search for bits in this bitmap.  We could only cover some
1682          * of the extent in this bitmap thanks to how we add space, so we need
1683          * to search for as much as it as we can and clear that amount, and then
1684          * go searching for the next bit.
1685          */
1686         search_start = *offset;
1687         search_bytes = ctl->unit;
1688         search_bytes = min(search_bytes, end - search_start + 1);
1689         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1690         if (ret < 0 || search_start != *offset)
1691                 return -EINVAL;
1692
1693         /* We may have found more bits than what we need */
1694         search_bytes = min(search_bytes, *bytes);
1695
1696         /* Cannot clear past the end of the bitmap */
1697         search_bytes = min(search_bytes, end - search_start + 1);
1698
1699         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1700         *offset += search_bytes;
1701         *bytes -= search_bytes;
1702
1703         if (*bytes) {
1704                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1705                 if (!bitmap_info->bytes)
1706                         free_bitmap(ctl, bitmap_info);
1707
1708                 /*
1709                  * no entry after this bitmap, but we still have bytes to
1710                  * remove, so something has gone wrong.
1711                  */
1712                 if (!next)
1713                         return -EINVAL;
1714
1715                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1716                                        offset_index);
1717
1718                 /*
1719                  * if the next entry isn't a bitmap we need to return to let the
1720                  * extent stuff do its work.
1721                  */
1722                 if (!bitmap_info->bitmap)
1723                         return -EAGAIN;
1724
1725                 /*
1726                  * Ok the next item is a bitmap, but it may not actually hold
1727                  * the information for the rest of this free space stuff, so
1728                  * look for it, and if we don't find it return so we can try
1729                  * everything over again.
1730                  */
1731                 search_start = *offset;
1732                 search_bytes = ctl->unit;
1733                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1734                                     &search_bytes);
1735                 if (ret < 0 || search_start != *offset)
1736                         return -EAGAIN;
1737
1738                 goto again;
1739         } else if (!bitmap_info->bytes)
1740                 free_bitmap(ctl, bitmap_info);
1741
1742         return 0;
1743 }
1744
1745 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1746                                struct btrfs_free_space *info, u64 offset,
1747                                u64 bytes)
1748 {
1749         u64 bytes_to_set = 0;
1750         u64 end;
1751
1752         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1753
1754         bytes_to_set = min(end - offset, bytes);
1755
1756         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1757
1758         return bytes_to_set;
1759
1760 }
1761
1762 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1763                       struct btrfs_free_space *info)
1764 {
1765         struct btrfs_block_group_cache *block_group = ctl->private;
1766
1767         /*
1768          * If we are below the extents threshold then we can add this as an
1769          * extent, and don't have to deal with the bitmap
1770          */
1771         if (ctl->free_extents < ctl->extents_thresh) {
1772                 /*
1773                  * If this block group has some small extents we don't want to
1774                  * use up all of our free slots in the cache with them, we want
1775                  * to reserve them to larger extents, however if we have plent
1776                  * of cache left then go ahead an dadd them, no sense in adding
1777                  * the overhead of a bitmap if we don't have to.
1778                  */
1779                 if (info->bytes <= block_group->sectorsize * 4) {
1780                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1781                                 return false;
1782                 } else {
1783                         return false;
1784                 }
1785         }
1786
1787         /*
1788          * The original block groups from mkfs can be really small, like 8
1789          * megabytes, so don't bother with a bitmap for those entries.  However
1790          * some block groups can be smaller than what a bitmap would cover but
1791          * are still large enough that they could overflow the 32k memory limit,
1792          * so allow those block groups to still be allowed to have a bitmap
1793          * entry.
1794          */
1795         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1796                 return false;
1797
1798         return true;
1799 }
1800
1801 static struct btrfs_free_space_op free_space_op = {
1802         .recalc_thresholds      = recalculate_thresholds,
1803         .use_bitmap             = use_bitmap,
1804 };
1805
1806 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1807                               struct btrfs_free_space *info)
1808 {
1809         struct btrfs_free_space *bitmap_info;
1810         struct btrfs_block_group_cache *block_group = NULL;
1811         int added = 0;
1812         u64 bytes, offset, bytes_added;
1813         int ret;
1814
1815         bytes = info->bytes;
1816         offset = info->offset;
1817
1818         if (!ctl->op->use_bitmap(ctl, info))
1819                 return 0;
1820
1821         if (ctl->op == &free_space_op)
1822                 block_group = ctl->private;
1823 again:
1824         /*
1825          * Since we link bitmaps right into the cluster we need to see if we
1826          * have a cluster here, and if so and it has our bitmap we need to add
1827          * the free space to that bitmap.
1828          */
1829         if (block_group && !list_empty(&block_group->cluster_list)) {
1830                 struct btrfs_free_cluster *cluster;
1831                 struct rb_node *node;
1832                 struct btrfs_free_space *entry;
1833
1834                 cluster = list_entry(block_group->cluster_list.next,
1835                                      struct btrfs_free_cluster,
1836                                      block_group_list);
1837                 spin_lock(&cluster->lock);
1838                 node = rb_first(&cluster->root);
1839                 if (!node) {
1840                         spin_unlock(&cluster->lock);
1841                         goto no_cluster_bitmap;
1842                 }
1843
1844                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1845                 if (!entry->bitmap) {
1846                         spin_unlock(&cluster->lock);
1847                         goto no_cluster_bitmap;
1848                 }
1849
1850                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1851                         bytes_added = add_bytes_to_bitmap(ctl, entry,
1852                                                           offset, bytes);
1853                         bytes -= bytes_added;
1854                         offset += bytes_added;
1855                 }
1856                 spin_unlock(&cluster->lock);
1857                 if (!bytes) {
1858                         ret = 1;
1859                         goto out;
1860                 }
1861         }
1862
1863 no_cluster_bitmap:
1864         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1865                                          1, 0);
1866         if (!bitmap_info) {
1867                 ASSERT(added == 0);
1868                 goto new_bitmap;
1869         }
1870
1871         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1872         bytes -= bytes_added;
1873         offset += bytes_added;
1874         added = 0;
1875
1876         if (!bytes) {
1877                 ret = 1;
1878                 goto out;
1879         } else
1880                 goto again;
1881
1882 new_bitmap:
1883         if (info && info->bitmap) {
1884                 add_new_bitmap(ctl, info, offset);
1885                 added = 1;
1886                 info = NULL;
1887                 goto again;
1888         } else {
1889                 spin_unlock(&ctl->tree_lock);
1890
1891                 /* no pre-allocated info, allocate a new one */
1892                 if (!info) {
1893                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
1894                                                  GFP_NOFS);
1895                         if (!info) {
1896                                 spin_lock(&ctl->tree_lock);
1897                                 ret = -ENOMEM;
1898                                 goto out;
1899                         }
1900                 }
1901
1902                 /* allocate the bitmap */
1903                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1904                 spin_lock(&ctl->tree_lock);
1905                 if (!info->bitmap) {
1906                         ret = -ENOMEM;
1907                         goto out;
1908                 }
1909                 goto again;
1910         }
1911
1912 out:
1913         if (info) {
1914                 if (info->bitmap)
1915                         kfree(info->bitmap);
1916                 kmem_cache_free(btrfs_free_space_cachep, info);
1917         }
1918
1919         return ret;
1920 }
1921
1922 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1923                           struct btrfs_free_space *info, bool update_stat)
1924 {
1925         struct btrfs_free_space *left_info;
1926         struct btrfs_free_space *right_info;
1927         bool merged = false;
1928         u64 offset = info->offset;
1929         u64 bytes = info->bytes;
1930
1931         /*
1932          * first we want to see if there is free space adjacent to the range we
1933          * are adding, if there is remove that struct and add a new one to
1934          * cover the entire range
1935          */
1936         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1937         if (right_info && rb_prev(&right_info->offset_index))
1938                 left_info = rb_entry(rb_prev(&right_info->offset_index),
1939                                      struct btrfs_free_space, offset_index);
1940         else
1941                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1942
1943         if (right_info && !right_info->bitmap) {
1944                 if (update_stat)
1945                         unlink_free_space(ctl, right_info);
1946                 else
1947                         __unlink_free_space(ctl, right_info);
1948                 info->bytes += right_info->bytes;
1949                 kmem_cache_free(btrfs_free_space_cachep, right_info);
1950                 merged = true;
1951         }
1952
1953         if (left_info && !left_info->bitmap &&
1954             left_info->offset + left_info->bytes == offset) {
1955                 if (update_stat)
1956                         unlink_free_space(ctl, left_info);
1957                 else
1958                         __unlink_free_space(ctl, left_info);
1959                 info->offset = left_info->offset;
1960                 info->bytes += left_info->bytes;
1961                 kmem_cache_free(btrfs_free_space_cachep, left_info);
1962                 merged = true;
1963         }
1964
1965         return merged;
1966 }
1967
1968 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1969                            u64 offset, u64 bytes)
1970 {
1971         struct btrfs_free_space *info;
1972         int ret = 0;
1973
1974         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1975         if (!info)
1976                 return -ENOMEM;
1977
1978         info->offset = offset;
1979         info->bytes = bytes;
1980
1981         spin_lock(&ctl->tree_lock);
1982
1983         if (try_merge_free_space(ctl, info, true))
1984                 goto link;
1985
1986         /*
1987          * There was no extent directly to the left or right of this new
1988          * extent then we know we're going to have to allocate a new extent, so
1989          * before we do that see if we need to drop this into a bitmap
1990          */
1991         ret = insert_into_bitmap(ctl, info);
1992         if (ret < 0) {
1993                 goto out;
1994         } else if (ret) {
1995                 ret = 0;
1996                 goto out;
1997         }
1998 link:
1999         ret = link_free_space(ctl, info);
2000         if (ret)
2001                 kmem_cache_free(btrfs_free_space_cachep, info);
2002 out:
2003         spin_unlock(&ctl->tree_lock);
2004
2005         if (ret) {
2006                 printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2007                 ASSERT(ret != -EEXIST);
2008         }
2009
2010         return ret;
2011 }
2012
2013 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2014                             u64 offset, u64 bytes)
2015 {
2016         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2017         struct btrfs_free_space *info;
2018         int ret;
2019         bool re_search = false;
2020
2021         spin_lock(&ctl->tree_lock);
2022
2023 again:
2024         ret = 0;
2025         if (!bytes)
2026                 goto out_lock;
2027
2028         info = tree_search_offset(ctl, offset, 0, 0);
2029         if (!info) {
2030                 /*
2031                  * oops didn't find an extent that matched the space we wanted
2032                  * to remove, look for a bitmap instead
2033                  */
2034                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2035                                           1, 0);
2036                 if (!info) {
2037                         /*
2038                          * If we found a partial bit of our free space in a
2039                          * bitmap but then couldn't find the other part this may
2040                          * be a problem, so WARN about it.
2041                          */
2042                         WARN_ON(re_search);
2043                         goto out_lock;
2044                 }
2045         }
2046
2047         re_search = false;
2048         if (!info->bitmap) {
2049                 unlink_free_space(ctl, info);
2050                 if (offset == info->offset) {
2051                         u64 to_free = min(bytes, info->bytes);
2052
2053                         info->bytes -= to_free;
2054                         info->offset += to_free;
2055                         if (info->bytes) {
2056                                 ret = link_free_space(ctl, info);
2057                                 WARN_ON(ret);
2058                         } else {
2059                                 kmem_cache_free(btrfs_free_space_cachep, info);
2060                         }
2061
2062                         offset += to_free;
2063                         bytes -= to_free;
2064                         goto again;
2065                 } else {
2066                         u64 old_end = info->bytes + info->offset;
2067
2068                         info->bytes = offset - info->offset;
2069                         ret = link_free_space(ctl, info);
2070                         WARN_ON(ret);
2071                         if (ret)
2072                                 goto out_lock;
2073
2074                         /* Not enough bytes in this entry to satisfy us */
2075                         if (old_end < offset + bytes) {
2076                                 bytes -= old_end - offset;
2077                                 offset = old_end;
2078                                 goto again;
2079                         } else if (old_end == offset + bytes) {
2080                                 /* all done */
2081                                 goto out_lock;
2082                         }
2083                         spin_unlock(&ctl->tree_lock);
2084
2085                         ret = btrfs_add_free_space(block_group, offset + bytes,
2086                                                    old_end - (offset + bytes));
2087                         WARN_ON(ret);
2088                         goto out;
2089                 }
2090         }
2091
2092         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2093         if (ret == -EAGAIN) {
2094                 re_search = true;
2095                 goto again;
2096         }
2097 out_lock:
2098         spin_unlock(&ctl->tree_lock);
2099 out:
2100         return ret;
2101 }
2102
2103 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2104                            u64 bytes)
2105 {
2106         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2107         struct btrfs_free_space *info;
2108         struct rb_node *n;
2109         int count = 0;
2110
2111         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2112                 info = rb_entry(n, struct btrfs_free_space, offset_index);
2113                 if (info->bytes >= bytes && !block_group->ro)
2114                         count++;
2115                 btrfs_crit(block_group->fs_info,
2116                            "entry offset %llu, bytes %llu, bitmap %s",
2117                            info->offset, info->bytes,
2118                        (info->bitmap) ? "yes" : "no");
2119         }
2120         btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2121                list_empty(&block_group->cluster_list) ? "no" : "yes");
2122         btrfs_info(block_group->fs_info,
2123                    "%d blocks of free space at or bigger than bytes is", count);
2124 }
2125
2126 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2127 {
2128         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2129
2130         spin_lock_init(&ctl->tree_lock);
2131         ctl->unit = block_group->sectorsize;
2132         ctl->start = block_group->key.objectid;
2133         ctl->private = block_group;
2134         ctl->op = &free_space_op;
2135
2136         /*
2137          * we only want to have 32k of ram per block group for keeping
2138          * track of free space, and if we pass 1/2 of that we want to
2139          * start converting things over to using bitmaps
2140          */
2141         ctl->extents_thresh = ((1024 * 32) / 2) /
2142                                 sizeof(struct btrfs_free_space);
2143 }
2144
2145 /*
2146  * for a given cluster, put all of its extents back into the free
2147  * space cache.  If the block group passed doesn't match the block group
2148  * pointed to by the cluster, someone else raced in and freed the
2149  * cluster already.  In that case, we just return without changing anything
2150  */
2151 static int
2152 __btrfs_return_cluster_to_free_space(
2153                              struct btrfs_block_group_cache *block_group,
2154                              struct btrfs_free_cluster *cluster)
2155 {
2156         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2157         struct btrfs_free_space *entry;
2158         struct rb_node *node;
2159
2160         spin_lock(&cluster->lock);
2161         if (cluster->block_group != block_group)
2162                 goto out;
2163
2164         cluster->block_group = NULL;
2165         cluster->window_start = 0;
2166         list_del_init(&cluster->block_group_list);
2167
2168         node = rb_first(&cluster->root);
2169         while (node) {
2170                 bool bitmap;
2171
2172                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2173                 node = rb_next(&entry->offset_index);
2174                 rb_erase(&entry->offset_index, &cluster->root);
2175
2176                 bitmap = (entry->bitmap != NULL);
2177                 if (!bitmap)
2178                         try_merge_free_space(ctl, entry, false);
2179                 tree_insert_offset(&ctl->free_space_offset,
2180                                    entry->offset, &entry->offset_index, bitmap);
2181         }
2182         cluster->root = RB_ROOT;
2183
2184 out:
2185         spin_unlock(&cluster->lock);
2186         btrfs_put_block_group(block_group);
2187         return 0;
2188 }
2189
2190 static void __btrfs_remove_free_space_cache_locked(
2191                                 struct btrfs_free_space_ctl *ctl)
2192 {
2193         struct btrfs_free_space *info;
2194         struct rb_node *node;
2195
2196         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2197                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2198                 if (!info->bitmap) {
2199                         unlink_free_space(ctl, info);
2200                         kmem_cache_free(btrfs_free_space_cachep, info);
2201                 } else {
2202                         free_bitmap(ctl, info);
2203                 }
2204                 if (need_resched()) {
2205                         spin_unlock(&ctl->tree_lock);
2206                         cond_resched();
2207                         spin_lock(&ctl->tree_lock);
2208                 }
2209         }
2210 }
2211
2212 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2213 {
2214         spin_lock(&ctl->tree_lock);
2215         __btrfs_remove_free_space_cache_locked(ctl);
2216         spin_unlock(&ctl->tree_lock);
2217 }
2218
2219 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2220 {
2221         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2222         struct btrfs_free_cluster *cluster;
2223         struct list_head *head;
2224
2225         spin_lock(&ctl->tree_lock);
2226         while ((head = block_group->cluster_list.next) !=
2227                &block_group->cluster_list) {
2228                 cluster = list_entry(head, struct btrfs_free_cluster,
2229                                      block_group_list);
2230
2231                 WARN_ON(cluster->block_group != block_group);
2232                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2233                 if (need_resched()) {
2234                         spin_unlock(&ctl->tree_lock);
2235                         cond_resched();
2236                         spin_lock(&ctl->tree_lock);
2237                 }
2238         }
2239         __btrfs_remove_free_space_cache_locked(ctl);
2240         spin_unlock(&ctl->tree_lock);
2241
2242 }
2243
2244 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2245                                u64 offset, u64 bytes, u64 empty_size,
2246                                u64 *max_extent_size)
2247 {
2248         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2249         struct btrfs_free_space *entry = NULL;
2250         u64 bytes_search = bytes + empty_size;
2251         u64 ret = 0;
2252         u64 align_gap = 0;
2253         u64 align_gap_len = 0;
2254
2255         spin_lock(&ctl->tree_lock);
2256         entry = find_free_space(ctl, &offset, &bytes_search,
2257                                 block_group->full_stripe_len, max_extent_size);
2258         if (!entry)
2259                 goto out;
2260
2261         ret = offset;
2262         if (entry->bitmap) {
2263                 bitmap_clear_bits(ctl, entry, offset, bytes);
2264                 if (!entry->bytes)
2265                         free_bitmap(ctl, entry);
2266         } else {
2267                 unlink_free_space(ctl, entry);
2268                 align_gap_len = offset - entry->offset;
2269                 align_gap = entry->offset;
2270
2271                 entry->offset = offset + bytes;
2272                 WARN_ON(entry->bytes < bytes + align_gap_len);
2273
2274                 entry->bytes -= bytes + align_gap_len;
2275                 if (!entry->bytes)
2276                         kmem_cache_free(btrfs_free_space_cachep, entry);
2277                 else
2278                         link_free_space(ctl, entry);
2279         }
2280 out:
2281         spin_unlock(&ctl->tree_lock);
2282
2283         if (align_gap_len)
2284                 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2285         return ret;
2286 }
2287
2288 /*
2289  * given a cluster, put all of its extents back into the free space
2290  * cache.  If a block group is passed, this function will only free
2291  * a cluster that belongs to the passed block group.
2292  *
2293  * Otherwise, it'll get a reference on the block group pointed to by the
2294  * cluster and remove the cluster from it.
2295  */
2296 int btrfs_return_cluster_to_free_space(
2297                                struct btrfs_block_group_cache *block_group,
2298                                struct btrfs_free_cluster *cluster)
2299 {
2300         struct btrfs_free_space_ctl *ctl;
2301         int ret;
2302
2303         /* first, get a safe pointer to the block group */
2304         spin_lock(&cluster->lock);
2305         if (!block_group) {
2306                 block_group = cluster->block_group;
2307                 if (!block_group) {
2308                         spin_unlock(&cluster->lock);
2309                         return 0;
2310                 }
2311         } else if (cluster->block_group != block_group) {
2312                 /* someone else has already freed it don't redo their work */
2313                 spin_unlock(&cluster->lock);
2314                 return 0;
2315         }
2316         atomic_inc(&block_group->count);
2317         spin_unlock(&cluster->lock);
2318
2319         ctl = block_group->free_space_ctl;
2320
2321         /* now return any extents the cluster had on it */
2322         spin_lock(&ctl->tree_lock);
2323         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2324         spin_unlock(&ctl->tree_lock);
2325
2326         /* finally drop our ref */
2327         btrfs_put_block_group(block_group);
2328         return ret;
2329 }
2330
2331 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2332                                    struct btrfs_free_cluster *cluster,
2333                                    struct btrfs_free_space *entry,
2334                                    u64 bytes, u64 min_start,
2335                                    u64 *max_extent_size)
2336 {
2337         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2338         int err;
2339         u64 search_start = cluster->window_start;
2340         u64 search_bytes = bytes;
2341         u64 ret = 0;
2342
2343         search_start = min_start;
2344         search_bytes = bytes;
2345
2346         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2347         if (err) {
2348                 if (search_bytes > *max_extent_size)
2349                         *max_extent_size = search_bytes;
2350                 return 0;
2351         }
2352
2353         ret = search_start;
2354         __bitmap_clear_bits(ctl, entry, ret, bytes);
2355
2356         return ret;
2357 }
2358
2359 /*
2360  * given a cluster, try to allocate 'bytes' from it, returns 0
2361  * if it couldn't find anything suitably large, or a logical disk offset
2362  * if things worked out
2363  */
2364 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2365                              struct btrfs_free_cluster *cluster, u64 bytes,
2366                              u64 min_start, u64 *max_extent_size)
2367 {
2368         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2369         struct btrfs_free_space *entry = NULL;
2370         struct rb_node *node;
2371         u64 ret = 0;
2372
2373         spin_lock(&cluster->lock);
2374         if (bytes > cluster->max_size)
2375                 goto out;
2376
2377         if (cluster->block_group != block_group)
2378                 goto out;
2379
2380         node = rb_first(&cluster->root);
2381         if (!node)
2382                 goto out;
2383
2384         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2385         while (1) {
2386                 if (entry->bytes < bytes && entry->bytes > *max_extent_size)
2387                         *max_extent_size = entry->bytes;
2388
2389                 if (entry->bytes < bytes ||
2390                     (!entry->bitmap && entry->offset < min_start)) {
2391                         node = rb_next(&entry->offset_index);
2392                         if (!node)
2393                                 break;
2394                         entry = rb_entry(node, struct btrfs_free_space,
2395                                          offset_index);
2396                         continue;
2397                 }
2398
2399                 if (entry->bitmap) {
2400                         ret = btrfs_alloc_from_bitmap(block_group,
2401                                                       cluster, entry, bytes,
2402                                                       cluster->window_start,
2403                                                       max_extent_size);
2404                         if (ret == 0) {
2405                                 node = rb_next(&entry->offset_index);
2406                                 if (!node)
2407                                         break;
2408                                 entry = rb_entry(node, struct btrfs_free_space,
2409                                                  offset_index);
2410                                 continue;
2411                         }
2412                         cluster->window_start += bytes;
2413                 } else {
2414                         ret = entry->offset;
2415
2416                         entry->offset += bytes;
2417                         entry->bytes -= bytes;
2418                 }
2419
2420                 if (entry->bytes == 0)
2421                         rb_erase(&entry->offset_index, &cluster->root);
2422                 break;
2423         }
2424 out:
2425         spin_unlock(&cluster->lock);
2426
2427         if (!ret)
2428                 return 0;
2429
2430         spin_lock(&ctl->tree_lock);
2431
2432         ctl->free_space -= bytes;
2433         if (entry->bytes == 0) {
2434                 ctl->free_extents--;
2435                 if (entry->bitmap) {
2436                         kfree(entry->bitmap);
2437                         ctl->total_bitmaps--;
2438                         ctl->op->recalc_thresholds(ctl);
2439                 }
2440                 kmem_cache_free(btrfs_free_space_cachep, entry);
2441         }
2442
2443         spin_unlock(&ctl->tree_lock);
2444
2445         return ret;
2446 }
2447
2448 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2449                                 struct btrfs_free_space *entry,
2450                                 struct btrfs_free_cluster *cluster,
2451                                 u64 offset, u64 bytes,
2452                                 u64 cont1_bytes, u64 min_bytes)
2453 {
2454         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2455         unsigned long next_zero;
2456         unsigned long i;
2457         unsigned long want_bits;
2458         unsigned long min_bits;
2459         unsigned long found_bits;
2460         unsigned long start = 0;
2461         unsigned long total_found = 0;
2462         int ret;
2463
2464         i = offset_to_bit(entry->offset, ctl->unit,
2465                           max_t(u64, offset, entry->offset));
2466         want_bits = bytes_to_bits(bytes, ctl->unit);
2467         min_bits = bytes_to_bits(min_bytes, ctl->unit);
2468
2469 again:
2470         found_bits = 0;
2471         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2472                 next_zero = find_next_zero_bit(entry->bitmap,
2473                                                BITS_PER_BITMAP, i);
2474                 if (next_zero - i >= min_bits) {
2475                         found_bits = next_zero - i;
2476                         break;
2477                 }
2478                 i = next_zero;
2479         }
2480
2481         if (!found_bits)
2482                 return -ENOSPC;
2483
2484         if (!total_found) {
2485                 start = i;
2486                 cluster->max_size = 0;
2487         }
2488
2489         total_found += found_bits;
2490
2491         if (cluster->max_size < found_bits * ctl->unit)
2492                 cluster->max_size = found_bits * ctl->unit;
2493
2494         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2495                 i = next_zero + 1;
2496                 goto again;
2497         }
2498
2499         cluster->window_start = start * ctl->unit + entry->offset;
2500         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2501         ret = tree_insert_offset(&cluster->root, entry->offset,
2502                                  &entry->offset_index, 1);
2503         ASSERT(!ret); /* -EEXIST; Logic error */
2504
2505         trace_btrfs_setup_cluster(block_group, cluster,
2506                                   total_found * ctl->unit, 1);
2507         return 0;
2508 }
2509
2510 /*
2511  * This searches the block group for just extents to fill the cluster with.
2512  * Try to find a cluster with at least bytes total bytes, at least one
2513  * extent of cont1_bytes, and other clusters of at least min_bytes.
2514  */
2515 static noinline int
2516 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2517                         struct btrfs_free_cluster *cluster,
2518                         struct list_head *bitmaps, u64 offset, u64 bytes,
2519                         u64 cont1_bytes, u64 min_bytes)
2520 {
2521         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2522         struct btrfs_free_space *first = NULL;
2523         struct btrfs_free_space *entry = NULL;
2524         struct btrfs_free_space *last;
2525         struct rb_node *node;
2526         u64 window_free;
2527         u64 max_extent;
2528         u64 total_size = 0;
2529
2530         entry = tree_search_offset(ctl, offset, 0, 1);
2531         if (!entry)
2532                 return -ENOSPC;
2533
2534         /*
2535          * We don't want bitmaps, so just move along until we find a normal
2536          * extent entry.
2537          */
2538         while (entry->bitmap || entry->bytes < min_bytes) {
2539                 if (entry->bitmap && list_empty(&entry->list))
2540                         list_add_tail(&entry->list, bitmaps);
2541                 node = rb_next(&entry->offset_index);
2542                 if (!node)
2543                         return -ENOSPC;
2544                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2545         }
2546
2547         window_free = entry->bytes;
2548         max_extent = entry->bytes;
2549         first = entry;
2550         last = entry;
2551
2552         for (node = rb_next(&entry->offset_index); node;
2553              node = rb_next(&entry->offset_index)) {
2554                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2555
2556                 if (entry->bitmap) {
2557                         if (list_empty(&entry->list))
2558                                 list_add_tail(&entry->list, bitmaps);
2559                         continue;
2560                 }
2561
2562                 if (entry->bytes < min_bytes)
2563                         continue;
2564
2565                 last = entry;
2566                 window_free += entry->bytes;
2567                 if (entry->bytes > max_extent)
2568                         max_extent = entry->bytes;
2569         }
2570
2571         if (window_free < bytes || max_extent < cont1_bytes)
2572                 return -ENOSPC;
2573
2574         cluster->window_start = first->offset;
2575
2576         node = &first->offset_index;
2577
2578         /*
2579          * now we've found our entries, pull them out of the free space
2580          * cache and put them into the cluster rbtree
2581          */
2582         do {
2583                 int ret;
2584
2585                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2586                 node = rb_next(&entry->offset_index);
2587                 if (entry->bitmap || entry->bytes < min_bytes)
2588                         continue;
2589
2590                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2591                 ret = tree_insert_offset(&cluster->root, entry->offset,
2592                                          &entry->offset_index, 0);
2593                 total_size += entry->bytes;
2594                 ASSERT(!ret); /* -EEXIST; Logic error */
2595         } while (node && entry != last);
2596
2597         cluster->max_size = max_extent;
2598         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2599         return 0;
2600 }
2601
2602 /*
2603  * This specifically looks for bitmaps that may work in the cluster, we assume
2604  * that we have already failed to find extents that will work.
2605  */
2606 static noinline int
2607 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2608                      struct btrfs_free_cluster *cluster,
2609                      struct list_head *bitmaps, u64 offset, u64 bytes,
2610                      u64 cont1_bytes, u64 min_bytes)
2611 {
2612         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2613         struct btrfs_free_space *entry;
2614         int ret = -ENOSPC;
2615         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2616
2617         if (ctl->total_bitmaps == 0)
2618                 return -ENOSPC;
2619
2620         /*
2621          * The bitmap that covers offset won't be in the list unless offset
2622          * is just its start offset.
2623          */
2624         entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2625         if (entry->offset != bitmap_offset) {
2626                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2627                 if (entry && list_empty(&entry->list))
2628                         list_add(&entry->list, bitmaps);
2629         }
2630
2631         list_for_each_entry(entry, bitmaps, list) {
2632                 if (entry->bytes < bytes)
2633                         continue;
2634                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2635                                            bytes, cont1_bytes, min_bytes);
2636                 if (!ret)
2637                         return 0;
2638         }
2639
2640         /*
2641          * The bitmaps list has all the bitmaps that record free space
2642          * starting after offset, so no more search is required.
2643          */
2644         return -ENOSPC;
2645 }
2646
2647 /*
2648  * here we try to find a cluster of blocks in a block group.  The goal
2649  * is to find at least bytes+empty_size.
2650  * We might not find them all in one contiguous area.
2651  *
2652  * returns zero and sets up cluster if things worked out, otherwise
2653  * it returns -enospc
2654  */
2655 int btrfs_find_space_cluster(struct btrfs_root *root,
2656                              struct btrfs_block_group_cache *block_group,
2657                              struct btrfs_free_cluster *cluster,
2658                              u64 offset, u64 bytes, u64 empty_size)
2659 {
2660         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2661         struct btrfs_free_space *entry, *tmp;
2662         LIST_HEAD(bitmaps);
2663         u64 min_bytes;
2664         u64 cont1_bytes;
2665         int ret;
2666
2667         /*
2668          * Choose the minimum extent size we'll require for this
2669          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2670          * For metadata, allow allocates with smaller extents.  For
2671          * data, keep it dense.
2672          */
2673         if (btrfs_test_opt(root, SSD_SPREAD)) {
2674                 cont1_bytes = min_bytes = bytes + empty_size;
2675         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2676                 cont1_bytes = bytes;
2677                 min_bytes = block_group->sectorsize;
2678         } else {
2679                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2680                 min_bytes = block_group->sectorsize;
2681         }
2682
2683         spin_lock(&ctl->tree_lock);
2684
2685         /*
2686          * If we know we don't have enough space to make a cluster don't even
2687          * bother doing all the work to try and find one.
2688          */
2689         if (ctl->free_space < bytes) {
2690                 spin_unlock(&ctl->tree_lock);
2691                 return -ENOSPC;
2692         }
2693
2694         spin_lock(&cluster->lock);
2695
2696         /* someone already found a cluster, hooray */
2697         if (cluster->block_group) {
2698                 ret = 0;
2699                 goto out;
2700         }
2701
2702         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2703                                  min_bytes);
2704
2705         INIT_LIST_HEAD(&bitmaps);
2706         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2707                                       bytes + empty_size,
2708                                       cont1_bytes, min_bytes);
2709         if (ret)
2710                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2711                                            offset, bytes + empty_size,
2712                                            cont1_bytes, min_bytes);
2713
2714         /* Clear our temporary list */
2715         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2716                 list_del_init(&entry->list);
2717
2718         if (!ret) {
2719                 atomic_inc(&block_group->count);
2720                 list_add_tail(&cluster->block_group_list,
2721                               &block_group->cluster_list);
2722                 cluster->block_group = block_group;
2723         } else {
2724                 trace_btrfs_failed_cluster_setup(block_group);
2725         }
2726 out:
2727         spin_unlock(&cluster->lock);
2728         spin_unlock(&ctl->tree_lock);
2729
2730         return ret;
2731 }
2732
2733 /*
2734  * simple code to zero out a cluster
2735  */
2736 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2737 {
2738         spin_lock_init(&cluster->lock);
2739         spin_lock_init(&cluster->refill_lock);
2740         cluster->root = RB_ROOT;
2741         cluster->max_size = 0;
2742         INIT_LIST_HEAD(&cluster->block_group_list);
2743         cluster->block_group = NULL;
2744 }
2745
2746 static int do_trimming(struct btrfs_block_group_cache *block_group,
2747                        u64 *total_trimmed, u64 start, u64 bytes,
2748                        u64 reserved_start, u64 reserved_bytes)
2749 {
2750         struct btrfs_space_info *space_info = block_group->space_info;
2751         struct btrfs_fs_info *fs_info = block_group->fs_info;
2752         int ret;
2753         int update = 0;
2754         u64 trimmed = 0;
2755
2756         spin_lock(&space_info->lock);
2757         spin_lock(&block_group->lock);
2758         if (!block_group->ro) {
2759                 block_group->reserved += reserved_bytes;
2760                 space_info->bytes_reserved += reserved_bytes;
2761                 update = 1;
2762         }
2763         spin_unlock(&block_group->lock);
2764         spin_unlock(&space_info->lock);
2765
2766         ret = btrfs_error_discard_extent(fs_info->extent_root,
2767                                          start, bytes, &trimmed);
2768         if (!ret)
2769                 *total_trimmed += trimmed;
2770
2771         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2772
2773         if (update) {
2774                 spin_lock(&space_info->lock);
2775                 spin_lock(&block_group->lock);
2776                 if (block_group->ro)
2777                         space_info->bytes_readonly += reserved_bytes;
2778                 block_group->reserved -= reserved_bytes;
2779                 space_info->bytes_reserved -= reserved_bytes;
2780                 spin_unlock(&space_info->lock);
2781                 spin_unlock(&block_group->lock);
2782         }
2783
2784         return ret;
2785 }
2786
2787 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2788                           u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2789 {
2790         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2791         struct btrfs_free_space *entry;
2792         struct rb_node *node;
2793         int ret = 0;
2794         u64 extent_start;
2795         u64 extent_bytes;
2796         u64 bytes;
2797
2798         while (start < end) {
2799                 spin_lock(&ctl->tree_lock);
2800
2801                 if (ctl->free_space < minlen) {
2802                         spin_unlock(&ctl->tree_lock);
2803                         break;
2804                 }
2805
2806                 entry = tree_search_offset(ctl, start, 0, 1);
2807                 if (!entry) {
2808                         spin_unlock(&ctl->tree_lock);
2809                         break;
2810                 }
2811
2812                 /* skip bitmaps */
2813                 while (entry->bitmap) {
2814                         node = rb_next(&entry->offset_index);
2815                         if (!node) {
2816                                 spin_unlock(&ctl->tree_lock);
2817                                 goto out;
2818                         }
2819                         entry = rb_entry(node, struct btrfs_free_space,
2820                                          offset_index);
2821                 }
2822
2823                 if (entry->offset >= end) {
2824                         spin_unlock(&ctl->tree_lock);
2825                         break;
2826                 }
2827
2828                 extent_start = entry->offset;
2829                 extent_bytes = entry->bytes;
2830                 start = max(start, extent_start);
2831                 bytes = min(extent_start + extent_bytes, end) - start;
2832                 if (bytes < minlen) {
2833                         spin_unlock(&ctl->tree_lock);
2834                         goto next;
2835                 }
2836
2837                 unlink_free_space(ctl, entry);
2838                 kmem_cache_free(btrfs_free_space_cachep, entry);
2839
2840                 spin_unlock(&ctl->tree_lock);
2841
2842                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2843                                   extent_start, extent_bytes);
2844                 if (ret)
2845                         break;
2846 next:
2847                 start += bytes;
2848
2849                 if (fatal_signal_pending(current)) {
2850                         ret = -ERESTARTSYS;
2851                         break;
2852                 }
2853
2854                 cond_resched();
2855         }
2856 out:
2857         return ret;
2858 }
2859
2860 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2861                         u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2862 {
2863         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2864         struct btrfs_free_space *entry;
2865         int ret = 0;
2866         int ret2;
2867         u64 bytes;
2868         u64 offset = offset_to_bitmap(ctl, start);
2869
2870         while (offset < end) {
2871                 bool next_bitmap = false;
2872
2873                 spin_lock(&ctl->tree_lock);
2874
2875                 if (ctl->free_space < minlen) {
2876                         spin_unlock(&ctl->tree_lock);
2877                         break;
2878                 }
2879
2880                 entry = tree_search_offset(ctl, offset, 1, 0);
2881                 if (!entry) {
2882                         spin_unlock(&ctl->tree_lock);
2883                         next_bitmap = true;
2884                         goto next;
2885                 }
2886
2887                 bytes = minlen;
2888                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2889                 if (ret2 || start >= end) {
2890                         spin_unlock(&ctl->tree_lock);
2891                         next_bitmap = true;
2892                         goto next;
2893                 }
2894
2895                 bytes = min(bytes, end - start);
2896                 if (bytes < minlen) {
2897                         spin_unlock(&ctl->tree_lock);
2898                         goto next;
2899                 }
2900
2901                 bitmap_clear_bits(ctl, entry, start, bytes);
2902                 if (entry->bytes == 0)
2903                         free_bitmap(ctl, entry);
2904
2905                 spin_unlock(&ctl->tree_lock);
2906
2907                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2908                                   start, bytes);
2909                 if (ret)
2910                         break;
2911 next:
2912                 if (next_bitmap) {
2913                         offset += BITS_PER_BITMAP * ctl->unit;
2914                 } else {
2915                         start += bytes;
2916                         if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2917                                 offset += BITS_PER_BITMAP * ctl->unit;
2918                 }
2919
2920                 if (fatal_signal_pending(current)) {
2921                         ret = -ERESTARTSYS;
2922                         break;
2923                 }
2924
2925                 cond_resched();
2926         }
2927
2928         return ret;
2929 }
2930
2931 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2932                            u64 *trimmed, u64 start, u64 end, u64 minlen)
2933 {
2934         int ret;
2935
2936         *trimmed = 0;
2937
2938         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2939         if (ret)
2940                 return ret;
2941
2942         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2943
2944         return ret;
2945 }
2946
2947 /*
2948  * Find the left-most item in the cache tree, and then return the
2949  * smallest inode number in the item.
2950  *
2951  * Note: the returned inode number may not be the smallest one in
2952  * the tree, if the left-most item is a bitmap.
2953  */
2954 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2955 {
2956         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2957         struct btrfs_free_space *entry = NULL;
2958         u64 ino = 0;
2959
2960         spin_lock(&ctl->tree_lock);
2961
2962         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2963                 goto out;
2964
2965         entry = rb_entry(rb_first(&ctl->free_space_offset),
2966                          struct btrfs_free_space, offset_index);
2967
2968         if (!entry->bitmap) {
2969                 ino = entry->offset;
2970
2971                 unlink_free_space(ctl, entry);
2972                 entry->offset++;
2973                 entry->bytes--;
2974                 if (!entry->bytes)
2975                         kmem_cache_free(btrfs_free_space_cachep, entry);
2976                 else
2977                         link_free_space(ctl, entry);
2978         } else {
2979                 u64 offset = 0;
2980                 u64 count = 1;
2981                 int ret;
2982
2983                 ret = search_bitmap(ctl, entry, &offset, &count);
2984                 /* Logic error; Should be empty if it can't find anything */
2985                 ASSERT(!ret);
2986
2987                 ino = offset;
2988                 bitmap_clear_bits(ctl, entry, offset, 1);
2989                 if (entry->bytes == 0)
2990                         free_bitmap(ctl, entry);
2991         }
2992 out:
2993         spin_unlock(&ctl->tree_lock);
2994
2995         return ino;
2996 }
2997
2998 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2999                                     struct btrfs_path *path)
3000 {
3001         struct inode *inode = NULL;
3002
3003         spin_lock(&root->cache_lock);
3004         if (root->cache_inode)
3005                 inode = igrab(root->cache_inode);
3006         spin_unlock(&root->cache_lock);
3007         if (inode)
3008                 return inode;
3009
3010         inode = __lookup_free_space_inode(root, path, 0);
3011         if (IS_ERR(inode))
3012                 return inode;
3013
3014         spin_lock(&root->cache_lock);
3015         if (!btrfs_fs_closing(root->fs_info))
3016                 root->cache_inode = igrab(inode);
3017         spin_unlock(&root->cache_lock);
3018
3019         return inode;
3020 }
3021
3022 int create_free_ino_inode(struct btrfs_root *root,
3023                           struct btrfs_trans_handle *trans,
3024                           struct btrfs_path *path)
3025 {
3026         return __create_free_space_inode(root, trans, path,
3027                                          BTRFS_FREE_INO_OBJECTID, 0);
3028 }
3029
3030 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3031 {
3032         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3033         struct btrfs_path *path;
3034         struct inode *inode;
3035         int ret = 0;
3036         u64 root_gen = btrfs_root_generation(&root->root_item);
3037
3038         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3039                 return 0;
3040
3041         /*
3042          * If we're unmounting then just return, since this does a search on the
3043          * normal root and not the commit root and we could deadlock.
3044          */
3045         if (btrfs_fs_closing(fs_info))
3046                 return 0;
3047
3048         path = btrfs_alloc_path();
3049         if (!path)
3050                 return 0;
3051
3052         inode = lookup_free_ino_inode(root, path);
3053         if (IS_ERR(inode))
3054                 goto out;
3055
3056         if (root_gen != BTRFS_I(inode)->generation)
3057                 goto out_put;
3058
3059         ret = __load_free_space_cache(root, inode, ctl, path, 0);
3060
3061         if (ret < 0)
3062                 btrfs_err(fs_info,
3063                         "failed to load free ino cache for root %llu",
3064                         root->root_key.objectid);
3065 out_put:
3066         iput(inode);
3067 out:
3068         btrfs_free_path(path);
3069         return ret;
3070 }
3071
3072 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3073                               struct btrfs_trans_handle *trans,
3074                               struct btrfs_path *path,
3075                               struct inode *inode)
3076 {
3077         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3078         int ret;
3079
3080         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3081                 return 0;
3082
3083         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
3084         if (ret) {
3085                 btrfs_delalloc_release_metadata(inode, inode->i_size);
3086 #ifdef DEBUG
3087                 btrfs_err(root->fs_info,
3088                         "failed to write free ino cache for root %llu",
3089                         root->root_key.objectid);
3090 #endif
3091         }
3092
3093         return ret;
3094 }
3095
3096 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3097 /*
3098  * Use this if you need to make a bitmap or extent entry specifically, it
3099  * doesn't do any of the merging that add_free_space does, this acts a lot like
3100  * how the free space cache loading stuff works, so you can get really weird
3101  * configurations.
3102  */
3103 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3104                               u64 offset, u64 bytes, bool bitmap)
3105 {
3106         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3107         struct btrfs_free_space *info = NULL, *bitmap_info;
3108         void *map = NULL;
3109         u64 bytes_added;
3110         int ret;
3111
3112 again:
3113         if (!info) {
3114                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3115                 if (!info)
3116                         return -ENOMEM;
3117         }
3118
3119         if (!bitmap) {
3120                 spin_lock(&ctl->tree_lock);
3121                 info->offset = offset;
3122                 info->bytes = bytes;
3123                 ret = link_free_space(ctl, info);
3124                 spin_unlock(&ctl->tree_lock);
3125                 if (ret)
3126                         kmem_cache_free(btrfs_free_space_cachep, info);
3127                 return ret;
3128         }
3129
3130         if (!map) {
3131                 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3132                 if (!map) {
3133                         kmem_cache_free(btrfs_free_space_cachep, info);
3134                         return -ENOMEM;
3135                 }
3136         }
3137
3138         spin_lock(&ctl->tree_lock);
3139         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3140                                          1, 0);
3141         if (!bitmap_info) {
3142                 info->bitmap = map;
3143                 map = NULL;
3144                 add_new_bitmap(ctl, info, offset);
3145                 bitmap_info = info;
3146         }
3147
3148         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3149         bytes -= bytes_added;
3150         offset += bytes_added;
3151         spin_unlock(&ctl->tree_lock);
3152
3153         if (bytes)
3154                 goto again;
3155
3156         if (map)
3157                 kfree(map);
3158         return 0;
3159 }
3160
3161 /*
3162  * Checks to see if the given range is in the free space cache.  This is really
3163  * just used to check the absence of space, so if there is free space in the
3164  * range at all we will return 1.
3165  */
3166 int test_check_exists(struct btrfs_block_group_cache *cache,
3167                       u64 offset, u64 bytes)
3168 {
3169         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3170         struct btrfs_free_space *info;
3171         int ret = 0;
3172
3173         spin_lock(&ctl->tree_lock);
3174         info = tree_search_offset(ctl, offset, 0, 0);
3175         if (!info) {
3176                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3177                                           1, 0);
3178                 if (!info)
3179                         goto out;
3180         }
3181
3182 have_info:
3183         if (info->bitmap) {
3184                 u64 bit_off, bit_bytes;
3185                 struct rb_node *n;
3186                 struct btrfs_free_space *tmp;
3187
3188                 bit_off = offset;
3189                 bit_bytes = ctl->unit;
3190                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3191                 if (!ret) {
3192                         if (bit_off == offset) {
3193                                 ret = 1;
3194                                 goto out;
3195                         } else if (bit_off > offset &&
3196                                    offset + bytes > bit_off) {
3197                                 ret = 1;
3198                                 goto out;
3199                         }
3200                 }
3201
3202                 n = rb_prev(&info->offset_index);
3203                 while (n) {
3204                         tmp = rb_entry(n, struct btrfs_free_space,
3205                                        offset_index);
3206                         if (tmp->offset + tmp->bytes < offset)
3207                                 break;
3208                         if (offset + bytes < tmp->offset) {
3209                                 n = rb_prev(&info->offset_index);
3210                                 continue;
3211                         }
3212                         info = tmp;
3213                         goto have_info;
3214                 }
3215
3216                 n = rb_next(&info->offset_index);
3217                 while (n) {
3218                         tmp = rb_entry(n, struct btrfs_free_space,
3219                                        offset_index);
3220                         if (offset + bytes < tmp->offset)
3221                                 break;
3222                         if (tmp->offset + tmp->bytes < offset) {
3223                                 n = rb_next(&info->offset_index);
3224                                 continue;
3225                         }
3226                         info = tmp;
3227                         goto have_info;
3228                 }
3229
3230                 goto out;
3231         }
3232
3233         if (info->offset == offset) {
3234                 ret = 1;
3235                 goto out;
3236         }
3237
3238         if (offset > info->offset && offset < info->offset + info->bytes)
3239                 ret = 1;
3240 out:
3241         spin_unlock(&ctl->tree_lock);
3242         return ret;
3243 }
3244 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */