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 #include "volumes.h"
  31
  32 #define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
  33 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
  34
  35 struct btrfs_trim_range {
  36         u64 start;
  37         u64 bytes;
  38         struct list_head list;
  39 };
  40
  41 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  42                            struct btrfs_free_space *info);
  43 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  44                               struct btrfs_free_space *info);
  45
  46 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  47                                                struct btrfs_path *path,
  48                                                u64 offset)
  49 {
  50         struct btrfs_key key;
  51         struct btrfs_key location;
  52         struct btrfs_disk_key disk_key;
  53         struct btrfs_free_space_header *header;
  54         struct extent_buffer *leaf;
  55         struct inode *inode = NULL;
  56         int ret;
  57
  58         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  59         key.offset = offset;
  60         key.type = 0;
  61
  62         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  63         if (ret < 0)
  64                 return ERR_PTR(ret);
  65         if (ret > 0) {
  66                 btrfs_release_path(path);
  67                 return ERR_PTR(-ENOENT);
  68         }
  69
  70         leaf = path->nodes[0];
  71         header = btrfs_item_ptr(leaf, path->slots[0],
  72                                 struct btrfs_free_space_header);
  73         btrfs_free_space_key(leaf, header, &disk_key);
  74         btrfs_disk_key_to_cpu(&location, &disk_key);
  75         btrfs_release_path(path);
  76
  77         inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
  78         if (!inode)
  79                 return ERR_PTR(-ENOENT);
  80         if (IS_ERR(inode))
  81                 return inode;
  82         if (is_bad_inode(inode)) {
  83                 iput(inode);
  84                 return ERR_PTR(-ENOENT);
  85         }
  86
  87         mapping_set_gfp_mask(inode->i_mapping,
  88                         mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
  89
  90         return inode;
  91 }
  92
  93 struct inode *lookup_free_space_inode(struct btrfs_root *root,
  94                                       struct btrfs_block_group_cache
  95                                       *block_group, struct btrfs_path *path)
  96 {
  97         struct inode *inode = NULL;
  98         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
  99
 100         spin_lock(&block_group->lock);
 101         if (block_group->inode)
 102                 inode = igrab(block_group->inode);
 103         spin_unlock(&block_group->lock);
 104         if (inode)
 105                 return inode;
 106
 107         inode = __lookup_free_space_inode(root, path,
 108                                           block_group->key.objectid);
 109         if (IS_ERR(inode))
 110                 return inode;
 111
 112         spin_lock(&block_group->lock);
 113         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 114                 btrfs_info(root->fs_info,
 115                         "Old style space inode found, converting.");
 116                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 117                         BTRFS_INODE_NODATACOW;
 118                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 119         }
 120
 121         if (!block_group->iref) {
 122                 block_group->inode = igrab(inode);
 123                 block_group->iref = 1;
 124         }
 125         spin_unlock(&block_group->lock);
 126
 127         return inode;
 128 }
 129
 130 static int __create_free_space_inode(struct btrfs_root *root,
 131                                      struct btrfs_trans_handle *trans,
 132                                      struct btrfs_path *path,
 133                                      u64 ino, u64 offset)
 134 {
 135         struct btrfs_key key;
 136         struct btrfs_disk_key disk_key;
 137         struct btrfs_free_space_header *header;
 138         struct btrfs_inode_item *inode_item;
 139         struct extent_buffer *leaf;
 140         u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 141         int ret;
 142
 143         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 144         if (ret)
 145                 return ret;
 146
 147         /* We inline crc's for the free disk space cache */
 148         if (ino != BTRFS_FREE_INO_OBJECTID)
 149                 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 150
 151         leaf = path->nodes[0];
 152         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 153                                     struct btrfs_inode_item);
 154         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 155         memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
 156                              sizeof(*inode_item));
 157         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 158         btrfs_set_inode_size(leaf, inode_item, 0);
 159         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 160         btrfs_set_inode_uid(leaf, inode_item, 0);
 161         btrfs_set_inode_gid(leaf, inode_item, 0);
 162         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 163         btrfs_set_inode_flags(leaf, inode_item, flags);
 164         btrfs_set_inode_nlink(leaf, inode_item, 1);
 165         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 166         btrfs_set_inode_block_group(leaf, inode_item, offset);
 167         btrfs_mark_buffer_dirty(leaf);
 168         btrfs_release_path(path);
 169
 170         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 171         key.offset = offset;
 172         key.type = 0;
 173
 174         ret = btrfs_insert_empty_item(trans, root, path, &key,
 175                                       sizeof(struct btrfs_free_space_header));
 176         if (ret < 0) {
 177                 btrfs_release_path(path);
 178                 return ret;
 179         }
 180         leaf = path->nodes[0];
 181         header = btrfs_item_ptr(leaf, path->slots[0],
 182                                 struct btrfs_free_space_header);
 183         memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
 184         btrfs_set_free_space_key(leaf, header, &disk_key);
 185         btrfs_mark_buffer_dirty(leaf);
 186         btrfs_release_path(path);
 187
 188         return 0;
 189 }
 190
 191 int create_free_space_inode(struct btrfs_root *root,
 192                             struct btrfs_trans_handle *trans,
 193                             struct btrfs_block_group_cache *block_group,
 194                             struct btrfs_path *path)
 195 {
 196         int ret;
 197         u64 ino;
 198
 199         ret = btrfs_find_free_objectid(root, &ino);
 200         if (ret < 0)
 201                 return ret;
 202
 203         return __create_free_space_inode(root, trans, path, ino,
 204                                          block_group->key.objectid);
 205 }
 206
 207 int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
 208                                        struct btrfs_block_rsv *rsv)
 209 {
 210         u64 needed_bytes;
 211         int ret;
 212
 213         /* 1 for slack space, 1 for updating the inode */
 214         needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
 215                 btrfs_calc_trans_metadata_size(root, 1);
 216
 217         spin_lock(&rsv->lock);
 218         if (rsv->reserved < needed_bytes)
 219                 ret = -ENOSPC;
 220         else
 221                 ret = 0;
 222         spin_unlock(&rsv->lock);
 223         return ret;
 224 }
 225
 226 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
 227                                     struct btrfs_trans_handle *trans,
 228                                     struct inode *inode)
 229 {
 230         int ret = 0;
 231
 232         btrfs_i_size_write(inode, 0);
 233         truncate_pagecache(inode, 0);
 234
 235         /*
 236          * We don't need an orphan item because truncating the free space cache
 237          * will never be split across transactions.
 238          */
 239         ret = btrfs_truncate_inode_items(trans, root, inode,
 240                                          0, BTRFS_EXTENT_DATA_KEY);
 241         if (ret) {
 242                 btrfs_abort_transaction(trans, root, ret);
 243                 return ret;
 244         }
 245
 246         ret = btrfs_update_inode(trans, root, inode);
 247         if (ret)
 248                 btrfs_abort_transaction(trans, root, ret);
 249
 250         return ret;
 251 }
 252
 253 static int readahead_cache(struct inode *inode)
 254 {
 255         struct file_ra_state *ra;
 256         unsigned long last_index;
 257
 258         ra = kzalloc(sizeof(*ra), GFP_NOFS);
 259         if (!ra)
 260                 return -ENOMEM;
 261
 262         file_ra_state_init(ra, inode->i_mapping);
 263         last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
 264
 265         page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 266
 267         kfree(ra);
 268
 269         return 0;
 270 }
 271
 272 struct io_ctl {
 273         void *cur, *orig;
 274         struct page *page;
 275         struct page **pages;
 276         struct btrfs_root *root;
 277         unsigned long size;
 278         int index;
 279         int num_pages;
 280         unsigned check_crcs:1;
 281 };
 282
 283 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
 284                        struct btrfs_root *root, int write)
 285 {
 286         int num_pages;
 287         int check_crcs = 0;
 288
 289         num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
 290
 291         if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
 292                 check_crcs = 1;
 293
 294         /* Make sure we can fit our crcs into the first page */
 295         if (write && check_crcs &&
 296             (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
 297                 return -ENOSPC;
 298
 299         memset(io_ctl, 0, sizeof(struct io_ctl));
 300
 301         io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
 302         if (!io_ctl->pages)
 303                 return -ENOMEM;
 304
 305         io_ctl->num_pages = num_pages;
 306         io_ctl->root = root;
 307         io_ctl->check_crcs = check_crcs;
 308
 309         return 0;
 310 }
 311
 312 static void io_ctl_free(struct io_ctl *io_ctl)
 313 {
 314         kfree(io_ctl->pages);
 315 }
 316
 317 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
 318 {
 319         if (io_ctl->cur) {
 320                 kunmap(io_ctl->page);
 321                 io_ctl->cur = NULL;
 322                 io_ctl->orig = NULL;
 323         }
 324 }
 325
 326 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
 327 {
 328         ASSERT(io_ctl->index < io_ctl->num_pages);
 329         io_ctl->page = io_ctl->pages[io_ctl->index++];
 330         io_ctl->cur = kmap(io_ctl->page);
 331         io_ctl->orig = io_ctl->cur;
 332         io_ctl->size = PAGE_CACHE_SIZE;
 333         if (clear)
 334                 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
 335 }
 336
 337 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
 338 {
 339         int i;
 340
 341         io_ctl_unmap_page(io_ctl);
 342
 343         for (i = 0; i < io_ctl->num_pages; i++) {
 344                 if (io_ctl->pages[i]) {
 345                         ClearPageChecked(io_ctl->pages[i]);
 346                         unlock_page(io_ctl->pages[i]);
 347                         page_cache_release(io_ctl->pages[i]);
 348                 }
 349         }
 350 }
 351
 352 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
 353                                 int uptodate)
 354 {
 355         struct page *page;
 356         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 357         int i;
 358
 359         for (i = 0; i < io_ctl->num_pages; i++) {
 360                 page = find_or_create_page(inode->i_mapping, i, mask);
 361                 if (!page) {
 362                         io_ctl_drop_pages(io_ctl);
 363                         return -ENOMEM;
 364                 }
 365                 io_ctl->pages[i] = page;
 366                 if (uptodate && !PageUptodate(page)) {
 367                         btrfs_readpage(NULL, page);
 368                         lock_page(page);
 369                         if (!PageUptodate(page)) {
 370                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 371                                            "error reading free space cache");
 372                                 io_ctl_drop_pages(io_ctl);
 373                                 return -EIO;
 374                         }
 375                 }
 376         }
 377
 378         for (i = 0; i < io_ctl->num_pages; i++) {
 379                 clear_page_dirty_for_io(io_ctl->pages[i]);
 380                 set_page_extent_mapped(io_ctl->pages[i]);
 381         }
 382
 383         return 0;
 384 }
 385
 386 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
 387 {
 388         __le64 *val;
 389
 390         io_ctl_map_page(io_ctl, 1);
 391
 392         /*
 393          * Skip the csum areas.  If we don't check crcs then we just have a
 394          * 64bit chunk at the front of the first page.
 395          */
 396         if (io_ctl->check_crcs) {
 397                 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 398                 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 399         } else {
 400                 io_ctl->cur += sizeof(u64);
 401                 io_ctl->size -= sizeof(u64) * 2;
 402         }
 403
 404         val = io_ctl->cur;
 405         *val = cpu_to_le64(generation);
 406         io_ctl->cur += sizeof(u64);
 407 }
 408
 409 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
 410 {
 411         __le64 *gen;
 412
 413         /*
 414          * Skip the crc area.  If we don't check crcs then we just have a 64bit
 415          * chunk at the front of the first page.
 416          */
 417         if (io_ctl->check_crcs) {
 418                 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 419                 io_ctl->size -= sizeof(u64) +
 420                         (sizeof(u32) * io_ctl->num_pages);
 421         } else {
 422                 io_ctl->cur += sizeof(u64);
 423                 io_ctl->size -= sizeof(u64) * 2;
 424         }
 425
 426         gen = io_ctl->cur;
 427         if (le64_to_cpu(*gen) != generation) {
 428                 printk_ratelimited(KERN_ERR "BTRFS: space cache generation "
 429                                    "(%Lu) does not match inode (%Lu)\n", *gen,
 430                                    generation);
 431                 io_ctl_unmap_page(io_ctl);
 432                 return -EIO;
 433         }
 434         io_ctl->cur += sizeof(u64);
 435         return 0;
 436 }
 437
 438 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
 439 {
 440         u32 *tmp;
 441         u32 crc = ~(u32)0;
 442         unsigned offset = 0;
 443
 444         if (!io_ctl->check_crcs) {
 445                 io_ctl_unmap_page(io_ctl);
 446                 return;
 447         }
 448
 449         if (index == 0)
 450                 offset = sizeof(u32) * io_ctl->num_pages;
 451
 452         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 453                               PAGE_CACHE_SIZE - offset);
 454         btrfs_csum_final(crc, (char *)&crc);
 455         io_ctl_unmap_page(io_ctl);
 456         tmp = kmap(io_ctl->pages[0]);
 457         tmp += index;
 458         *tmp = crc;
 459         kunmap(io_ctl->pages[0]);
 460 }
 461
 462 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
 463 {
 464         u32 *tmp, val;
 465         u32 crc = ~(u32)0;
 466         unsigned offset = 0;
 467
 468         if (!io_ctl->check_crcs) {
 469                 io_ctl_map_page(io_ctl, 0);
 470                 return 0;
 471         }
 472
 473         if (index == 0)
 474                 offset = sizeof(u32) * io_ctl->num_pages;
 475
 476         tmp = kmap(io_ctl->pages[0]);
 477         tmp += index;
 478         val = *tmp;
 479         kunmap(io_ctl->pages[0]);
 480
 481         io_ctl_map_page(io_ctl, 0);
 482         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 483                               PAGE_CACHE_SIZE - offset);
 484         btrfs_csum_final(crc, (char *)&crc);
 485         if (val != crc) {
 486                 printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free "
 487                                    "space cache\n");
 488                 io_ctl_unmap_page(io_ctl);
 489                 return -EIO;
 490         }
 491
 492         return 0;
 493 }
 494
 495 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
 496                             void *bitmap)
 497 {
 498         struct btrfs_free_space_entry *entry;
 499
 500         if (!io_ctl->cur)
 501                 return -ENOSPC;
 502
 503         entry = io_ctl->cur;
 504         entry->offset = cpu_to_le64(offset);
 505         entry->bytes = cpu_to_le64(bytes);
 506         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 507                 BTRFS_FREE_SPACE_EXTENT;
 508         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 509         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 510
 511         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 512                 return 0;
 513
 514         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 515
 516         /* No more pages to map */
 517         if (io_ctl->index >= io_ctl->num_pages)
 518                 return 0;
 519
 520         /* map the next page */
 521         io_ctl_map_page(io_ctl, 1);
 522         return 0;
 523 }
 524
 525 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
 526 {
 527         if (!io_ctl->cur)
 528                 return -ENOSPC;
 529
 530         /*
 531          * If we aren't at the start of the current page, unmap this one and
 532          * map the next one if there is any left.
 533          */
 534         if (io_ctl->cur != io_ctl->orig) {
 535                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 536                 if (io_ctl->index >= io_ctl->num_pages)
 537                         return -ENOSPC;
 538                 io_ctl_map_page(io_ctl, 0);
 539         }
 540
 541         memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
 542         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 543         if (io_ctl->index < io_ctl->num_pages)
 544                 io_ctl_map_page(io_ctl, 0);
 545         return 0;
 546 }
 547
 548 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
 549 {
 550         /*
 551          * If we're not on the boundary we know we've modified the page and we
 552          * need to crc the page.
 553          */
 554         if (io_ctl->cur != io_ctl->orig)
 555                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 556         else
 557                 io_ctl_unmap_page(io_ctl);
 558
 559         while (io_ctl->index < io_ctl->num_pages) {
 560                 io_ctl_map_page(io_ctl, 1);
 561                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 562         }
 563 }
 564
 565 static int io_ctl_read_entry(struct io_ctl *io_ctl,
 566                             struct btrfs_free_space *entry, u8 *type)
 567 {
 568         struct btrfs_free_space_entry *e;
 569         int ret;
 570
 571         if (!io_ctl->cur) {
 572                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 573                 if (ret)
 574                         return ret;
 575         }
 576
 577         e = io_ctl->cur;
 578         entry->offset = le64_to_cpu(e->offset);
 579         entry->bytes = le64_to_cpu(e->bytes);
 580         *type = e->type;
 581         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 582         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 583
 584         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 585                 return 0;
 586
 587         io_ctl_unmap_page(io_ctl);
 588
 589         return 0;
 590 }
 591
 592 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
 593                               struct btrfs_free_space *entry)
 594 {
 595         int ret;
 596
 597         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 598         if (ret)
 599                 return ret;
 600
 601         memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
 602         io_ctl_unmap_page(io_ctl);
 603
 604         return 0;
 605 }
 606
 607 /*
 608  * Since we attach pinned extents after the fact we can have contiguous sections
 609  * of free space that are split up in entries.  This poses a problem with the
 610  * tree logging stuff since it could have allocated across what appears to be 2
 611  * entries since we would have merged the entries when adding the pinned extents
 612  * back to the free space cache.  So run through the space cache that we just
 613  * loaded and merge contiguous entries.  This will make the log replay stuff not
 614  * blow up and it will make for nicer allocator behavior.
 615  */
 616 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
 617 {
 618         struct btrfs_free_space *e, *prev = NULL;
 619         struct rb_node *n;
 620
 621 again:
 622         spin_lock(&ctl->tree_lock);
 623         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 624                 e = rb_entry(n, struct btrfs_free_space, offset_index);
 625                 if (!prev)
 626                         goto next;
 627                 if (e->bitmap || prev->bitmap)
 628                         goto next;
 629                 if (prev->offset + prev->bytes == e->offset) {
 630                         unlink_free_space(ctl, prev);
 631                         unlink_free_space(ctl, e);
 632                         prev->bytes += e->bytes;
 633                         kmem_cache_free(btrfs_free_space_cachep, e);
 634                         link_free_space(ctl, prev);
 635                         prev = NULL;
 636                         spin_unlock(&ctl->tree_lock);
 637                         goto again;
 638                 }
 639 next:
 640                 prev = e;
 641         }
 642         spin_unlock(&ctl->tree_lock);
 643 }
 644
 645 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 646                                    struct btrfs_free_space_ctl *ctl,
 647                                    struct btrfs_path *path, u64 offset)
 648 {
 649         struct btrfs_free_space_header *header;
 650         struct extent_buffer *leaf;
 651         struct io_ctl io_ctl;
 652         struct btrfs_key key;
 653         struct btrfs_free_space *e, *n;
 654         LIST_HEAD(bitmaps);
 655         u64 num_entries;
 656         u64 num_bitmaps;
 657         u64 generation;
 658         u8 type;
 659         int ret = 0;
 660
 661         /* Nothing in the space cache, goodbye */
 662         if (!i_size_read(inode))
 663                 return 0;
 664
 665         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 666         key.offset = offset;
 667         key.type = 0;
 668
 669         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 670         if (ret < 0)
 671                 return 0;
 672         else if (ret > 0) {
 673                 btrfs_release_path(path);
 674                 return 0;
 675         }
 676
 677         ret = -1;
 678
 679         leaf = path->nodes[0];
 680         header = btrfs_item_ptr(leaf, path->slots[0],
 681                                 struct btrfs_free_space_header);
 682         num_entries = btrfs_free_space_entries(leaf, header);
 683         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 684         generation = btrfs_free_space_generation(leaf, header);
 685         btrfs_release_path(path);
 686
 687         if (!BTRFS_I(inode)->generation) {
 688                 btrfs_info(root->fs_info,
 689                            "The free space cache file (%llu) is invalid. skip it\n",
 690                            offset);
 691                 return 0;
 692         }
 693
 694         if (BTRFS_I(inode)->generation != generation) {
 695                 btrfs_err(root->fs_info,
 696                         "free space inode generation (%llu) "
 697                         "did not match free space cache generation (%llu)",
 698                         BTRFS_I(inode)->generation, generation);
 699                 return 0;
 700         }
 701
 702         if (!num_entries)
 703                 return 0;
 704
 705         ret = io_ctl_init(&io_ctl, inode, root, 0);
 706         if (ret)
 707                 return ret;
 708
 709         ret = readahead_cache(inode);
 710         if (ret)
 711                 goto out;
 712
 713         ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
 714         if (ret)
 715                 goto out;
 716
 717         ret = io_ctl_check_crc(&io_ctl, 0);
 718         if (ret)
 719                 goto free_cache;
 720
 721         ret = io_ctl_check_generation(&io_ctl, generation);
 722         if (ret)
 723                 goto free_cache;
 724
 725         while (num_entries) {
 726                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
 727                                       GFP_NOFS);
 728                 if (!e)
 729                         goto free_cache;
 730
 731                 ret = io_ctl_read_entry(&io_ctl, e, &type);
 732                 if (ret) {
 733                         kmem_cache_free(btrfs_free_space_cachep, e);
 734                         goto free_cache;
 735                 }
 736
 737                 if (!e->bytes) {
 738                         kmem_cache_free(btrfs_free_space_cachep, e);
 739                         goto free_cache;
 740                 }
 741
 742                 if (type == BTRFS_FREE_SPACE_EXTENT) {
 743                         spin_lock(&ctl->tree_lock);
 744                         ret = link_free_space(ctl, e);
 745                         spin_unlock(&ctl->tree_lock);
 746                         if (ret) {
 747                                 btrfs_err(root->fs_info,
 748                                         "Duplicate entries in free space cache, dumping");
 749                                 kmem_cache_free(btrfs_free_space_cachep, e);
 750                                 goto free_cache;
 751                         }
 752                 } else {
 753                         ASSERT(num_bitmaps);
 754                         num_bitmaps--;
 755                         e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 756                         if (!e->bitmap) {
 757                                 kmem_cache_free(
 758                                         btrfs_free_space_cachep, e);
 759                                 goto free_cache;
 760                         }
 761                         spin_lock(&ctl->tree_lock);
 762                         ret = link_free_space(ctl, e);
 763                         ctl->total_bitmaps++;
 764                         ctl->op->recalc_thresholds(ctl);
 765                         spin_unlock(&ctl->tree_lock);
 766                         if (ret) {
 767                                 btrfs_err(root->fs_info,
 768                                         "Duplicate entries in free space cache, dumping");
 769                                 kmem_cache_free(btrfs_free_space_cachep, e);
 770                                 goto free_cache;
 771                         }
 772                         list_add_tail(&e->list, &bitmaps);
 773                 }
 774
 775                 num_entries--;
 776         }
 777
 778         io_ctl_unmap_page(&io_ctl);
 779
 780         /*
 781          * We add the bitmaps at the end of the entries in order that
 782          * the bitmap entries are added to the cache.
 783          */
 784         list_for_each_entry_safe(e, n, &bitmaps, list) {
 785                 list_del_init(&e->list);
 786                 ret = io_ctl_read_bitmap(&io_ctl, e);
 787                 if (ret)
 788                         goto free_cache;
 789         }
 790
 791         io_ctl_drop_pages(&io_ctl);
 792         merge_space_tree(ctl);
 793         ret = 1;
 794 out:
 795         io_ctl_free(&io_ctl);
 796         return ret;
 797 free_cache:
 798         io_ctl_drop_pages(&io_ctl);
 799         __btrfs_remove_free_space_cache(ctl);
 800         goto out;
 801 }
 802
 803 int load_free_space_cache(struct btrfs_fs_info *fs_info,
 804                           struct btrfs_block_group_cache *block_group)
 805 {
 806         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 807         struct btrfs_root *root = fs_info->tree_root;
 808         struct inode *inode;
 809         struct btrfs_path *path;
 810         int ret = 0;
 811         bool matched;
 812         u64 used = btrfs_block_group_used(&block_group->item);
 813
 814         /*
 815          * If this block group has been marked to be cleared for one reason or
 816          * another then we can't trust the on disk cache, so just return.
 817          */
 818         spin_lock(&block_group->lock);
 819         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 820                 spin_unlock(&block_group->lock);
 821                 return 0;
 822         }
 823         spin_unlock(&block_group->lock);
 824
 825         path = btrfs_alloc_path();
 826         if (!path)
 827                 return 0;
 828         path->search_commit_root = 1;
 829         path->skip_locking = 1;
 830
 831         inode = lookup_free_space_inode(root, block_group, path);
 832         if (IS_ERR(inode)) {
 833                 btrfs_free_path(path);
 834                 return 0;
 835         }
 836
 837         /* We may have converted the inode and made the cache invalid. */
 838         spin_lock(&block_group->lock);
 839         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 840                 spin_unlock(&block_group->lock);
 841                 btrfs_free_path(path);
 842                 goto out;
 843         }
 844         spin_unlock(&block_group->lock);
 845
 846         ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 847                                       path, block_group->key.objectid);
 848         btrfs_free_path(path);
 849         if (ret <= 0)
 850                 goto out;
 851
 852         spin_lock(&ctl->tree_lock);
 853         matched = (ctl->free_space == (block_group->key.offset - used -
 854                                        block_group->bytes_super));
 855         spin_unlock(&ctl->tree_lock);
 856
 857         if (!matched) {
 858                 __btrfs_remove_free_space_cache(ctl);
 859                 btrfs_warn(fs_info, "block group %llu has wrong amount of free space",
 860                         block_group->key.objectid);
 861                 ret = -1;
 862         }
 863 out:
 864         if (ret < 0) {
 865                 /* This cache is bogus, make sure it gets cleared */
 866                 spin_lock(&block_group->lock);
 867                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 868                 spin_unlock(&block_group->lock);
 869                 ret = 0;
 870
 871                 btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now",
 872                         block_group->key.objectid);
 873         }
 874
 875         iput(inode);
 876         return ret;
 877 }
 878
 879 static noinline_for_stack
 880 int write_cache_extent_entries(struct io_ctl *io_ctl,
 881                               struct btrfs_free_space_ctl *ctl,
 882                               struct btrfs_block_group_cache *block_group,
 883                               int *entries, int *bitmaps,
 884                               struct list_head *bitmap_list)
 885 {
 886         int ret;
 887         struct btrfs_free_cluster *cluster = NULL;
 888         struct rb_node *node = rb_first(&ctl->free_space_offset);
 889         struct btrfs_trim_range *trim_entry;
 890
 891         /* Get the cluster for this block_group if it exists */
 892         if (block_group && !list_empty(&block_group->cluster_list)) {
 893                 cluster = list_entry(block_group->cluster_list.next,
 894                                      struct btrfs_free_cluster,
 895                                      block_group_list);
 896         }
 897
 898         if (!node && cluster) {
 899                 node = rb_first(&cluster->root);
 900                 cluster = NULL;
 901         }
 902
 903         /* Write out the extent entries */
 904         while (node) {
 905                 struct btrfs_free_space *e;
 906
 907                 e = rb_entry(node, struct btrfs_free_space, offset_index);
 908                 *entries += 1;
 909
 910                 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
 911                                        e->bitmap);
 912                 if (ret)
 913                         goto fail;
 914
 915                 if (e->bitmap) {
 916                         list_add_tail(&e->list, bitmap_list);
 917                         *bitmaps += 1;
 918                 }
 919                 node = rb_next(node);
 920                 if (!node && cluster) {
 921                         node = rb_first(&cluster->root);
 922                         cluster = NULL;
 923                 }
 924         }
 925
 926         /*
 927          * Make sure we don't miss any range that was removed from our rbtree
 928          * because trimming is running. Otherwise after a umount+mount (or crash
 929          * after committing the transaction) we would leak free space and get
 930          * an inconsistent free space cache report from fsck.
 931          */
 932         list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
 933                 ret = io_ctl_add_entry(io_ctl, trim_entry->start,
 934                                        trim_entry->bytes, NULL);
 935                 if (ret)
 936                         goto fail;
 937                 *entries += 1;
 938         }
 939
 940         return 0;
 941 fail:
 942         return -ENOSPC;
 943 }
 944
 945 static noinline_for_stack int
 946 update_cache_item(struct btrfs_trans_handle *trans,
 947                   struct btrfs_root *root,
 948                   struct inode *inode,
 949                   struct btrfs_path *path, u64 offset,
 950                   int entries, int bitmaps)
 951 {
 952         struct btrfs_key key;
 953         struct btrfs_free_space_header *header;
 954         struct extent_buffer *leaf;
 955         int ret;
 956
 957         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 958         key.offset = offset;
 959         key.type = 0;
 960
 961         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 962         if (ret < 0) {
 963                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
 964                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
 965                                  GFP_NOFS);
 966                 goto fail;
 967         }
 968         leaf = path->nodes[0];
 969         if (ret > 0) {
 970                 struct btrfs_key found_key;
 971                 ASSERT(path->slots[0]);
 972                 path->slots[0]--;
 973                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 974                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
 975                     found_key.offset != offset) {
 976                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
 977                                          inode->i_size - 1,
 978                                          EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
 979                                          NULL, GFP_NOFS);
 980                         btrfs_release_path(path);
 981                         goto fail;
 982                 }
 983         }
 984
 985         BTRFS_I(inode)->generation = trans->transid;
 986         header = btrfs_item_ptr(leaf, path->slots[0],
 987                                 struct btrfs_free_space_header);
 988         btrfs_set_free_space_entries(leaf, header, entries);
 989         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
 990         btrfs_set_free_space_generation(leaf, header, trans->transid);
 991         btrfs_mark_buffer_dirty(leaf);
 992         btrfs_release_path(path);
 993
 994         return 0;
 995
 996 fail:
 997         return -1;
 998 }
 999
1000 static noinline_for_stack int
1001 write_pinned_extent_entries(struct btrfs_root *root,
1002                             struct btrfs_block_group_cache *block_group,
1003                             struct io_ctl *io_ctl,
1004                             int *entries)
1005 {
1006         u64 start, extent_start, extent_end, len;
1007         struct extent_io_tree *unpin = NULL;
1008         int ret;
1009
1010         if (!block_group)
1011                 return 0;
1012
1013         /*
1014          * We want to add any pinned extents to our free space cache
1015          * so we don't leak the space
1016          *
1017          * We shouldn't have switched the pinned extents yet so this is the
1018          * right one
1019          */
1020         unpin = root->fs_info->pinned_extents;
1021
1022         start = block_group->key.objectid;
1023
1024         while (start < block_group->key.objectid + block_group->key.offset) {
1025                 ret = find_first_extent_bit(unpin, start,
1026                                             &extent_start, &extent_end,
1027                                             EXTENT_DIRTY, NULL);
1028                 if (ret)
1029                         return 0;
1030
1031                 /* This pinned extent is out of our range */
1032                 if (extent_start >= block_group->key.objectid +
1033                     block_group->key.offset)
1034                         return 0;
1035
1036                 extent_start = max(extent_start, start);
1037                 extent_end = min(block_group->key.objectid +
1038                                  block_group->key.offset, extent_end + 1);
1039                 len = extent_end - extent_start;
1040
1041                 *entries += 1;
1042                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1043                 if (ret)
1044                         return -ENOSPC;
1045
1046                 start = extent_end;
1047         }
1048
1049         return 0;
1050 }
1051
1052 static noinline_for_stack int
1053 write_bitmap_entries(struct io_ctl *io_ctl, struct list_head *bitmap_list)
1054 {
1055         struct list_head *pos, *n;
1056         int ret;
1057
1058         /* Write out the bitmaps */
1059         list_for_each_safe(pos, n, bitmap_list) {
1060                 struct btrfs_free_space *entry =
1061                         list_entry(pos, struct btrfs_free_space, list);
1062
1063                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1064                 if (ret)
1065                         return -ENOSPC;
1066                 list_del_init(&entry->list);
1067         }
1068
1069         return 0;
1070 }
1071
1072 static int flush_dirty_cache(struct inode *inode)
1073 {
1074         int ret;
1075
1076         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1077         if (ret)
1078                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1079                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1080                                  GFP_NOFS);
1081
1082         return ret;
1083 }
1084
1085 static void noinline_for_stack
1086 cleanup_write_cache_enospc(struct inode *inode,
1087                            struct io_ctl *io_ctl,
1088                            struct extent_state **cached_state,
1089                            struct list_head *bitmap_list)
1090 {
1091         struct list_head *pos, *n;
1092
1093         list_for_each_safe(pos, n, bitmap_list) {
1094                 struct btrfs_free_space *entry =
1095                         list_entry(pos, struct btrfs_free_space, list);
1096                 list_del_init(&entry->list);
1097         }
1098         io_ctl_drop_pages(io_ctl);
1099         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1100                              i_size_read(inode) - 1, cached_state,
1101                              GFP_NOFS);
1102 }
1103
1104 /**
1105  * __btrfs_write_out_cache - write out cached info to an inode
1106  * @root - the root the inode belongs to
1107  * @ctl - the free space cache we are going to write out
1108  * @block_group - the block_group for this cache if it belongs to a block_group
1109  * @trans - the trans handle
1110  * @path - the path to use
1111  * @offset - the offset for the key we'll insert
1112  *
1113  * This function writes out a free space cache struct to disk for quick recovery
1114  * on mount.  This will return 0 if it was successfull in writing the cache out,
1115  * and -1 if it was not.
1116  */
1117 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1118                                    struct btrfs_free_space_ctl *ctl,
1119                                    struct btrfs_block_group_cache *block_group,
1120                                    struct btrfs_trans_handle *trans,
1121                                    struct btrfs_path *path, u64 offset)
1122 {
1123         struct extent_state *cached_state = NULL;
1124         struct io_ctl io_ctl;
1125         LIST_HEAD(bitmap_list);
1126         int entries = 0;
1127         int bitmaps = 0;
1128         int ret;
1129
1130         if (!i_size_read(inode))
1131                 return -1;
1132
1133         ret = io_ctl_init(&io_ctl, inode, root, 1);
1134         if (ret)
1135                 return -1;
1136
1137         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1138                 down_write(&block_group->data_rwsem);
1139                 spin_lock(&block_group->lock);
1140                 if (block_group->delalloc_bytes) {
1141                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1142                         spin_unlock(&block_group->lock);
1143                         up_write(&block_group->data_rwsem);
1144                         BTRFS_I(inode)->generation = 0;
1145                         ret = 0;
1146                         goto out;
1147                 }
1148                 spin_unlock(&block_group->lock);
1149         }
1150
1151         /* Lock all pages first so we can lock the extent safely. */
1152         io_ctl_prepare_pages(&io_ctl, inode, 0);
1153
1154         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1155                          0, &cached_state);
1156
1157         io_ctl_set_generation(&io_ctl, trans->transid);
1158
1159         mutex_lock(&ctl->cache_writeout_mutex);
1160         /* Write out the extent entries in the free space cache */
1161         ret = write_cache_extent_entries(&io_ctl, ctl,
1162                                          block_group, &entries, &bitmaps,
1163                                          &bitmap_list);
1164         if (ret) {
1165                 mutex_unlock(&ctl->cache_writeout_mutex);
1166                 goto out_nospc;
1167         }
1168
1169         /*
1170          * Some spaces that are freed in the current transaction are pinned,
1171          * they will be added into free space cache after the transaction is
1172          * committed, we shouldn't lose them.
1173          */
1174         ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
1175         if (ret) {
1176                 mutex_unlock(&ctl->cache_writeout_mutex);
1177                 goto out_nospc;
1178         }
1179
1180         /*
1181          * At last, we write out all the bitmaps and keep cache_writeout_mutex
1182          * locked while doing it because a concurrent trim can be manipulating
1183          * or freeing the bitmap.
1184          */
1185         ret = write_bitmap_entries(&io_ctl, &bitmap_list);
1186         mutex_unlock(&ctl->cache_writeout_mutex);
1187         if (ret)
1188                 goto out_nospc;
1189
1190         /* Zero out the rest of the pages just to make sure */
1191         io_ctl_zero_remaining_pages(&io_ctl);
1192
1193         /* Everything is written out, now we dirty the pages in the file. */
1194         ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1195                                 0, i_size_read(inode), &cached_state);
1196         if (ret)
1197                 goto out_nospc;
1198
1199         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1200                 up_write(&block_group->data_rwsem);
1201         /*
1202          * Release the pages and unlock the extent, we will flush
1203          * them out later
1204          */
1205         io_ctl_drop_pages(&io_ctl);
1206
1207         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1208                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1209
1210         /* Flush the dirty pages in the cache file. */
1211         ret = flush_dirty_cache(inode);
1212         if (ret)
1213                 goto out;
1214
1215         /* Update the cache item to tell everyone this cache file is valid. */
1216         ret = update_cache_item(trans, root, inode, path, offset,
1217                                 entries, bitmaps);
1218 out:
1219         io_ctl_free(&io_ctl);
1220         if (ret) {
1221                 invalidate_inode_pages2(inode->i_mapping);
1222                 BTRFS_I(inode)->generation = 0;
1223         }
1224         btrfs_update_inode(trans, root, inode);
1225         return ret;
1226
1227 out_nospc:
1228         cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list);
1229
1230         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1231                 up_write(&block_group->data_rwsem);
1232
1233         goto out;
1234 }
1235
1236 int btrfs_write_out_cache(struct btrfs_root *root,
1237                           struct btrfs_trans_handle *trans,
1238                           struct btrfs_block_group_cache *block_group,
1239                           struct btrfs_path *path)
1240 {
1241         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1242         struct inode *inode;
1243         int ret = 0;
1244         enum btrfs_disk_cache_state dcs = BTRFS_DC_WRITTEN;
1245
1246         root = root->fs_info->tree_root;
1247
1248         spin_lock(&block_group->lock);
1249         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1250                 spin_unlock(&block_group->lock);
1251                 return 0;
1252         }
1253
1254         if (block_group->delalloc_bytes) {
1255                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1256                 spin_unlock(&block_group->lock);
1257                 return 0;
1258         }
1259         spin_unlock(&block_group->lock);
1260
1261         inode = lookup_free_space_inode(root, block_group, path);
1262         if (IS_ERR(inode))
1263                 return 0;
1264
1265         ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1266                                       path, block_group->key.objectid);
1267         if (ret) {
1268                 dcs = BTRFS_DC_ERROR;
1269                 ret = 0;
1270 #ifdef DEBUG
1271                 btrfs_err(root->fs_info,
1272                         "failed to write free space cache for block group %llu",
1273                         block_group->key.objectid);
1274 #endif
1275         }
1276
1277         spin_lock(&block_group->lock);
1278         block_group->disk_cache_state = dcs;
1279         spin_unlock(&block_group->lock);
1280         iput(inode);
1281         return ret;
1282 }
1283
1284 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1285                                           u64 offset)
1286 {
1287         ASSERT(offset >= bitmap_start);
1288         offset -= bitmap_start;
1289         return (unsigned long)(div_u64(offset, unit));
1290 }
1291
1292 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1293 {
1294         return (unsigned long)(div_u64(bytes, unit));
1295 }
1296
1297 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1298                                    u64 offset)
1299 {
1300         u64 bitmap_start;
1301         u32 bytes_per_bitmap;
1302
1303         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1304         bitmap_start = offset - ctl->start;
1305         bitmap_start = div_u64(bitmap_start, bytes_per_bitmap);
1306         bitmap_start *= bytes_per_bitmap;
1307         bitmap_start += ctl->start;
1308
1309         return bitmap_start;
1310 }
1311
1312 static int tree_insert_offset(struct rb_root *root, u64 offset,
1313                               struct rb_node *node, int bitmap)
1314 {
1315         struct rb_node **p = &root->rb_node;
1316         struct rb_node *parent = NULL;
1317         struct btrfs_free_space *info;
1318
1319         while (*p) {
1320                 parent = *p;
1321                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1322
1323                 if (offset < info->offset) {
1324                         p = &(*p)->rb_left;
1325                 } else if (offset > info->offset) {
1326                         p = &(*p)->rb_right;
1327                 } else {
1328                         /*
1329                          * we could have a bitmap entry and an extent entry
1330                          * share the same offset.  If this is the case, we want
1331                          * the extent entry to always be found first if we do a
1332                          * linear search through the tree, since we want to have
1333                          * the quickest allocation time, and allocating from an
1334                          * extent is faster than allocating from a bitmap.  So
1335                          * if we're inserting a bitmap and we find an entry at
1336                          * this offset, we want to go right, or after this entry
1337                          * logically.  If we are inserting an extent and we've
1338                          * found a bitmap, we want to go left, or before
1339                          * logically.
1340                          */
1341                         if (bitmap) {
1342                                 if (info->bitmap) {
1343                                         WARN_ON_ONCE(1);
1344                                         return -EEXIST;
1345                                 }
1346                                 p = &(*p)->rb_right;
1347                         } else {
1348                                 if (!info->bitmap) {
1349                                         WARN_ON_ONCE(1);
1350                                         return -EEXIST;
1351                                 }
1352                                 p = &(*p)->rb_left;
1353                         }
1354                 }
1355         }
1356
1357         rb_link_node(node, parent, p);
1358         rb_insert_color(node, root);
1359
1360         return 0;
1361 }
1362
1363 /*
1364  * searches the tree for the given offset.
1365  *
1366  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1367  * want a section that has at least bytes size and comes at or after the given
1368  * offset.
1369  */
1370 static struct btrfs_free_space *
1371 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1372                    u64 offset, int bitmap_only, int fuzzy)
1373 {
1374         struct rb_node *n = ctl->free_space_offset.rb_node;
1375         struct btrfs_free_space *entry, *prev = NULL;
1376
1377         /* find entry that is closest to the 'offset' */
1378         while (1) {
1379                 if (!n) {
1380                         entry = NULL;
1381                         break;
1382                 }
1383
1384                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1385                 prev = entry;
1386
1387                 if (offset < entry->offset)
1388                         n = n->rb_left;
1389                 else if (offset > entry->offset)
1390                         n = n->rb_right;
1391                 else
1392                         break;
1393         }
1394
1395         if (bitmap_only) {
1396                 if (!entry)
1397                         return NULL;
1398                 if (entry->bitmap)
1399                         return entry;
1400
1401                 /*
1402                  * bitmap entry and extent entry may share same offset,
1403                  * in that case, bitmap entry comes after extent entry.
1404                  */
1405                 n = rb_next(n);
1406                 if (!n)
1407                         return NULL;
1408                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1409                 if (entry->offset != offset)
1410                         return NULL;
1411
1412                 WARN_ON(!entry->bitmap);
1413                 return entry;
1414         } else if (entry) {
1415                 if (entry->bitmap) {
1416                         /*
1417                          * if previous extent entry covers the offset,
1418                          * we should return it instead of the bitmap entry
1419                          */
1420                         n = rb_prev(&entry->offset_index);
1421                         if (n) {
1422                                 prev = rb_entry(n, struct btrfs_free_space,
1423                                                 offset_index);
1424                                 if (!prev->bitmap &&
1425                                     prev->offset + prev->bytes > offset)
1426                                         entry = prev;
1427                         }
1428                 }
1429                 return entry;
1430         }
1431
1432         if (!prev)
1433                 return NULL;
1434
1435         /* find last entry before the 'offset' */
1436         entry = prev;
1437         if (entry->offset > offset) {
1438                 n = rb_prev(&entry->offset_index);
1439                 if (n) {
1440                         entry = rb_entry(n, struct btrfs_free_space,
1441                                         offset_index);
1442                         ASSERT(entry->offset <= offset);
1443                 } else {
1444                         if (fuzzy)
1445                                 return entry;
1446                         else
1447                                 return NULL;
1448                 }
1449         }
1450
1451         if (entry->bitmap) {
1452                 n = rb_prev(&entry->offset_index);
1453                 if (n) {
1454                         prev = rb_entry(n, struct btrfs_free_space,
1455                                         offset_index);
1456                         if (!prev->bitmap &&
1457                             prev->offset + prev->bytes > offset)
1458                                 return prev;
1459                 }
1460                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1461                         return entry;
1462         } else if (entry->offset + entry->bytes > offset)
1463                 return entry;
1464
1465         if (!fuzzy)
1466                 return NULL;
1467
1468         while (1) {
1469                 if (entry->bitmap) {
1470                         if (entry->offset + BITS_PER_BITMAP *
1471                             ctl->unit > offset)
1472                                 break;
1473                 } else {
1474                         if (entry->offset + entry->bytes > offset)
1475                                 break;
1476                 }
1477
1478                 n = rb_next(&entry->offset_index);
1479                 if (!n)
1480                         return NULL;
1481                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1482         }
1483         return entry;
1484 }
1485
1486 static inline void
1487 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1488                     struct btrfs_free_space *info)
1489 {
1490         rb_erase(&info->offset_index, &ctl->free_space_offset);
1491         ctl->free_extents--;
1492 }
1493
1494 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1495                               struct btrfs_free_space *info)
1496 {
1497         __unlink_free_space(ctl, info);
1498         ctl->free_space -= info->bytes;
1499 }
1500
1501 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1502                            struct btrfs_free_space *info)
1503 {
1504         int ret = 0;
1505
1506         ASSERT(info->bytes || info->bitmap);
1507         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1508                                  &info->offset_index, (info->bitmap != NULL));
1509         if (ret)
1510                 return ret;
1511
1512         ctl->free_space += info->bytes;
1513         ctl->free_extents++;
1514         return ret;
1515 }
1516
1517 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1518 {
1519         struct btrfs_block_group_cache *block_group = ctl->private;
1520         u64 max_bytes;
1521         u64 bitmap_bytes;
1522         u64 extent_bytes;
1523         u64 size = block_group->key.offset;
1524         u32 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1525         u32 max_bitmaps = div_u64(size + bytes_per_bg - 1, bytes_per_bg);
1526
1527         max_bitmaps = max_t(u32, max_bitmaps, 1);
1528
1529         ASSERT(ctl->total_bitmaps <= max_bitmaps);
1530
1531         /*
1532          * The goal is to keep the total amount of memory used per 1gb of space
1533          * at or below 32k, so we need to adjust how much memory we allow to be
1534          * used by extent based free space tracking
1535          */
1536         if (size < 1024 * 1024 * 1024)
1537                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1538         else
1539                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1540                         div_u64(size, 1024 * 1024 * 1024);
1541
1542         /*
1543          * we want to account for 1 more bitmap than what we have so we can make
1544          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1545          * we add more bitmaps.
1546          */
1547         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1548
1549         if (bitmap_bytes >= max_bytes) {
1550                 ctl->extents_thresh = 0;
1551                 return;
1552         }
1553
1554         /*
1555          * we want the extent entry threshold to always be at most 1/2 the max
1556          * bytes we can have, or whatever is less than that.
1557          */
1558         extent_bytes = max_bytes - bitmap_bytes;
1559         extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
1560
1561         ctl->extents_thresh =
1562                 div_u64(extent_bytes, sizeof(struct btrfs_free_space));
1563 }
1564
1565 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1566                                        struct btrfs_free_space *info,
1567                                        u64 offset, u64 bytes)
1568 {
1569         unsigned long start, count;
1570
1571         start = offset_to_bit(info->offset, ctl->unit, offset);
1572         count = bytes_to_bits(bytes, ctl->unit);
1573         ASSERT(start + count <= BITS_PER_BITMAP);
1574
1575         bitmap_clear(info->bitmap, start, count);
1576
1577         info->bytes -= bytes;
1578 }
1579
1580 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1581                               struct btrfs_free_space *info, u64 offset,
1582                               u64 bytes)
1583 {
1584         __bitmap_clear_bits(ctl, info, offset, bytes);
1585         ctl->free_space -= bytes;
1586 }
1587
1588 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1589                             struct btrfs_free_space *info, u64 offset,
1590                             u64 bytes)
1591 {
1592         unsigned long start, count;
1593
1594         start = offset_to_bit(info->offset, ctl->unit, offset);
1595         count = bytes_to_bits(bytes, ctl->unit);
1596         ASSERT(start + count <= BITS_PER_BITMAP);
1597
1598         bitmap_set(info->bitmap, start, count);
1599
1600         info->bytes += bytes;
1601         ctl->free_space += bytes;
1602 }
1603
1604 /*
1605  * If we can not find suitable extent, we will use bytes to record
1606  * the size of the max extent.
1607  */
1608 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1609                          struct btrfs_free_space *bitmap_info, u64 *offset,
1610                          u64 *bytes)
1611 {
1612         unsigned long found_bits = 0;
1613         unsigned long max_bits = 0;
1614         unsigned long bits, i;
1615         unsigned long next_zero;
1616         unsigned long extent_bits;
1617
1618         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1619                           max_t(u64, *offset, bitmap_info->offset));
1620         bits = bytes_to_bits(*bytes, ctl->unit);
1621
1622         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1623                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1624                                                BITS_PER_BITMAP, i);
1625                 extent_bits = next_zero - i;
1626                 if (extent_bits >= bits) {
1627                         found_bits = extent_bits;
1628                         break;
1629                 } else if (extent_bits > max_bits) {
1630                         max_bits = extent_bits;
1631                 }
1632                 i = next_zero;
1633         }
1634
1635         if (found_bits) {
1636                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1637                 *bytes = (u64)(found_bits) * ctl->unit;
1638                 return 0;
1639         }
1640
1641         *bytes = (u64)(max_bits) * ctl->unit;
1642         return -1;
1643 }
1644
1645 /* Cache the size of the max extent in bytes */
1646 static struct btrfs_free_space *
1647 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1648                 unsigned long align, u64 *max_extent_size)
1649 {
1650         struct btrfs_free_space *entry;
1651         struct rb_node *node;
1652         u64 tmp;
1653         u64 align_off;
1654         int ret;
1655
1656         if (!ctl->free_space_offset.rb_node)
1657                 goto out;
1658
1659         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1660         if (!entry)
1661                 goto out;
1662
1663         for (node = &entry->offset_index; node; node = rb_next(node)) {
1664                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1665                 if (entry->bytes < *bytes) {
1666                         if (entry->bytes > *max_extent_size)
1667                                 *max_extent_size = entry->bytes;
1668                         continue;
1669                 }
1670
1671                 /* make sure the space returned is big enough
1672                  * to match our requested alignment
1673                  */
1674                 if (*bytes >= align) {
1675                         tmp = entry->offset - ctl->start + align - 1;
1676                         do_div(tmp, align);
1677                         tmp = tmp * align + ctl->start;
1678                         align_off = tmp - entry->offset;
1679                 } else {
1680                         align_off = 0;
1681                         tmp = entry->offset;
1682                 }
1683
1684                 if (entry->bytes < *bytes + align_off) {
1685                         if (entry->bytes > *max_extent_size)
1686                                 *max_extent_size = entry->bytes;
1687                         continue;
1688                 }
1689
1690                 if (entry->bitmap) {
1691                         u64 size = *bytes;
1692
1693                         ret = search_bitmap(ctl, entry, &tmp, &size);
1694                         if (!ret) {
1695                                 *offset = tmp;
1696                                 *bytes = size;
1697                                 return entry;
1698                         } else if (size > *max_extent_size) {
1699                                 *max_extent_size = size;
1700                         }
1701                         continue;
1702                 }
1703
1704                 *offset = tmp;
1705                 *bytes = entry->bytes - align_off;
1706                 return entry;
1707         }
1708 out:
1709         return NULL;
1710 }
1711
1712 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1713                            struct btrfs_free_space *info, u64 offset)
1714 {
1715         info->offset = offset_to_bitmap(ctl, offset);
1716         info->bytes = 0;
1717         INIT_LIST_HEAD(&info->list);
1718         link_free_space(ctl, info);
1719         ctl->total_bitmaps++;
1720
1721         ctl->op->recalc_thresholds(ctl);
1722 }
1723
1724 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1725                         struct btrfs_free_space *bitmap_info)
1726 {
1727         unlink_free_space(ctl, bitmap_info);
1728         kfree(bitmap_info->bitmap);
1729         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1730         ctl->total_bitmaps--;
1731         ctl->op->recalc_thresholds(ctl);
1732 }
1733
1734 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1735                               struct btrfs_free_space *bitmap_info,
1736                               u64 *offset, u64 *bytes)
1737 {
1738         u64 end;
1739         u64 search_start, search_bytes;
1740         int ret;
1741
1742 again:
1743         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1744
1745         /*
1746          * We need to search for bits in this bitmap.  We could only cover some
1747          * of the extent in this bitmap thanks to how we add space, so we need
1748          * to search for as much as it as we can and clear that amount, and then
1749          * go searching for the next bit.
1750          */
1751         search_start = *offset;
1752         search_bytes = ctl->unit;
1753         search_bytes = min(search_bytes, end - search_start + 1);
1754         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1755         if (ret < 0 || search_start != *offset)
1756                 return -EINVAL;
1757
1758         /* We may have found more bits than what we need */
1759         search_bytes = min(search_bytes, *bytes);
1760
1761         /* Cannot clear past the end of the bitmap */
1762         search_bytes = min(search_bytes, end - search_start + 1);
1763
1764         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1765         *offset += search_bytes;
1766         *bytes -= search_bytes;
1767
1768         if (*bytes) {
1769                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1770                 if (!bitmap_info->bytes)
1771                         free_bitmap(ctl, bitmap_info);
1772
1773                 /*
1774                  * no entry after this bitmap, but we still have bytes to
1775                  * remove, so something has gone wrong.
1776                  */
1777                 if (!next)
1778                         return -EINVAL;
1779
1780                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1781                                        offset_index);
1782
1783                 /*
1784                  * if the next entry isn't a bitmap we need to return to let the
1785                  * extent stuff do its work.
1786                  */
1787                 if (!bitmap_info->bitmap)
1788                         return -EAGAIN;
1789
1790                 /*
1791                  * Ok the next item is a bitmap, but it may not actually hold
1792                  * the information for the rest of this free space stuff, so
1793                  * look for it, and if we don't find it return so we can try
1794                  * everything over again.
1795                  */
1796                 search_start = *offset;
1797                 search_bytes = ctl->unit;
1798                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1799                                     &search_bytes);
1800                 if (ret < 0 || search_start != *offset)
1801                         return -EAGAIN;
1802
1803                 goto again;
1804         } else if (!bitmap_info->bytes)
1805                 free_bitmap(ctl, bitmap_info);
1806
1807         return 0;
1808 }
1809
1810 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1811                                struct btrfs_free_space *info, u64 offset,
1812                                u64 bytes)
1813 {
1814         u64 bytes_to_set = 0;
1815         u64 end;
1816
1817         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1818
1819         bytes_to_set = min(end - offset, bytes);
1820
1821         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1822
1823         return bytes_to_set;
1824
1825 }
1826
1827 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1828                       struct btrfs_free_space *info)
1829 {
1830         struct btrfs_block_group_cache *block_group = ctl->private;
1831
1832         /*
1833          * If we are below the extents threshold then we can add this as an
1834          * extent, and don't have to deal with the bitmap
1835          */
1836         if (ctl->free_extents < ctl->extents_thresh) {
1837                 /*
1838                  * If this block group has some small extents we don't want to
1839                  * use up all of our free slots in the cache with them, we want
1840                  * to reserve them to larger extents, however if we have plent
1841                  * of cache left then go ahead an dadd them, no sense in adding
1842                  * the overhead of a bitmap if we don't have to.
1843                  */
1844                 if (info->bytes <= block_group->sectorsize * 4) {
1845                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1846                                 return false;
1847                 } else {
1848                         return false;
1849                 }
1850         }
1851
1852         /*
1853          * The original block groups from mkfs can be really small, like 8
1854          * megabytes, so don't bother with a bitmap for those entries.  However
1855          * some block groups can be smaller than what a bitmap would cover but
1856          * are still large enough that they could overflow the 32k memory limit,
1857          * so allow those block groups to still be allowed to have a bitmap
1858          * entry.
1859          */
1860         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1861                 return false;
1862
1863         return true;
1864 }
1865
1866 static struct btrfs_free_space_op free_space_op = {
1867         .recalc_thresholds      = recalculate_thresholds,
1868         .use_bitmap             = use_bitmap,
1869 };
1870
1871 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1872                               struct btrfs_free_space *info)
1873 {
1874         struct btrfs_free_space *bitmap_info;
1875         struct btrfs_block_group_cache *block_group = NULL;
1876         int added = 0;
1877         u64 bytes, offset, bytes_added;
1878         int ret;
1879
1880         bytes = info->bytes;
1881         offset = info->offset;
1882
1883         if (!ctl->op->use_bitmap(ctl, info))
1884                 return 0;
1885
1886         if (ctl->op == &free_space_op)
1887                 block_group = ctl->private;
1888 again:
1889         /*
1890          * Since we link bitmaps right into the cluster we need to see if we
1891          * have a cluster here, and if so and it has our bitmap we need to add
1892          * the free space to that bitmap.
1893          */
1894         if (block_group && !list_empty(&block_group->cluster_list)) {
1895                 struct btrfs_free_cluster *cluster;
1896                 struct rb_node *node;
1897                 struct btrfs_free_space *entry;
1898
1899                 cluster = list_entry(block_group->cluster_list.next,
1900                                      struct btrfs_free_cluster,
1901                                      block_group_list);
1902                 spin_lock(&cluster->lock);
1903                 node = rb_first(&cluster->root);
1904                 if (!node) {
1905                         spin_unlock(&cluster->lock);
1906                         goto no_cluster_bitmap;
1907                 }
1908
1909                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1910                 if (!entry->bitmap) {
1911                         spin_unlock(&cluster->lock);
1912                         goto no_cluster_bitmap;
1913                 }
1914
1915                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1916                         bytes_added = add_bytes_to_bitmap(ctl, entry,
1917                                                           offset, bytes);
1918                         bytes -= bytes_added;
1919                         offset += bytes_added;
1920                 }
1921                 spin_unlock(&cluster->lock);
1922                 if (!bytes) {
1923                         ret = 1;
1924                         goto out;
1925                 }
1926         }
1927
1928 no_cluster_bitmap:
1929         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1930                                          1, 0);
1931         if (!bitmap_info) {
1932                 ASSERT(added == 0);
1933                 goto new_bitmap;
1934         }
1935
1936         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1937         bytes -= bytes_added;
1938         offset += bytes_added;
1939         added = 0;
1940
1941         if (!bytes) {
1942                 ret = 1;
1943                 goto out;
1944         } else
1945                 goto again;
1946
1947 new_bitmap:
1948         if (info && info->bitmap) {
1949                 add_new_bitmap(ctl, info, offset);
1950                 added = 1;
1951                 info = NULL;
1952                 goto again;
1953         } else {
1954                 spin_unlock(&ctl->tree_lock);
1955
1956                 /* no pre-allocated info, allocate a new one */
1957                 if (!info) {
1958                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
1959                                                  GFP_NOFS);
1960                         if (!info) {
1961                                 spin_lock(&ctl->tree_lock);
1962                                 ret = -ENOMEM;
1963                                 goto out;
1964                         }
1965                 }
1966
1967                 /* allocate the bitmap */
1968                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1969                 spin_lock(&ctl->tree_lock);
1970                 if (!info->bitmap) {
1971                         ret = -ENOMEM;
1972                         goto out;
1973                 }
1974                 goto again;
1975         }
1976
1977 out:
1978         if (info) {
1979                 if (info->bitmap)
1980                         kfree(info->bitmap);
1981                 kmem_cache_free(btrfs_free_space_cachep, info);
1982         }
1983
1984         return ret;
1985 }
1986
1987 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1988                           struct btrfs_free_space *info, bool update_stat)
1989 {
1990         struct btrfs_free_space *left_info;
1991         struct btrfs_free_space *right_info;
1992         bool merged = false;
1993         u64 offset = info->offset;
1994         u64 bytes = info->bytes;
1995
1996         /*
1997          * first we want to see if there is free space adjacent to the range we
1998          * are adding, if there is remove that struct and add a new one to
1999          * cover the entire range
2000          */
2001         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2002         if (right_info && rb_prev(&right_info->offset_index))
2003                 left_info = rb_entry(rb_prev(&right_info->offset_index),
2004                                      struct btrfs_free_space, offset_index);
2005         else
2006                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2007
2008         if (right_info && !right_info->bitmap) {
2009                 if (update_stat)
2010                         unlink_free_space(ctl, right_info);
2011                 else
2012                         __unlink_free_space(ctl, right_info);
2013                 info->bytes += right_info->bytes;
2014                 kmem_cache_free(btrfs_free_space_cachep, right_info);
2015                 merged = true;
2016         }
2017
2018         if (left_info && !left_info->bitmap &&
2019             left_info->offset + left_info->bytes == offset) {
2020                 if (update_stat)
2021                         unlink_free_space(ctl, left_info);
2022                 else
2023                         __unlink_free_space(ctl, left_info);
2024                 info->offset = left_info->offset;
2025                 info->bytes += left_info->bytes;
2026                 kmem_cache_free(btrfs_free_space_cachep, left_info);
2027                 merged = true;
2028         }
2029
2030         return merged;
2031 }
2032
2033 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2034                                      struct btrfs_free_space *info,
2035                                      bool update_stat)
2036 {
2037         struct btrfs_free_space *bitmap;
2038         unsigned long i;
2039         unsigned long j;
2040         const u64 end = info->offset + info->bytes;
2041         const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2042         u64 bytes;
2043
2044         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2045         if (!bitmap)
2046                 return false;
2047
2048         i = offset_to_bit(bitmap->offset, ctl->unit, end);
2049         j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2050         if (j == i)
2051                 return false;
2052         bytes = (j - i) * ctl->unit;
2053         info->bytes += bytes;
2054
2055         if (update_stat)
2056                 bitmap_clear_bits(ctl, bitmap, end, bytes);
2057         else
2058                 __bitmap_clear_bits(ctl, bitmap, end, bytes);
2059
2060         if (!bitmap->bytes)
2061                 free_bitmap(ctl, bitmap);
2062
2063         return true;
2064 }
2065
2066 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2067                                        struct btrfs_free_space *info,
2068                                        bool update_stat)
2069 {
2070         struct btrfs_free_space *bitmap;
2071         u64 bitmap_offset;
2072         unsigned long i;
2073         unsigned long j;
2074         unsigned long prev_j;
2075         u64 bytes;
2076
2077         bitmap_offset = offset_to_bitmap(ctl, info->offset);
2078         /* If we're on a boundary, try the previous logical bitmap. */
2079         if (bitmap_offset == info->offset) {
2080                 if (info->offset == 0)
2081                         return false;
2082                 bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2083         }
2084
2085         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2086         if (!bitmap)
2087                 return false;
2088
2089         i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2090         j = 0;
2091         prev_j = (unsigned long)-1;
2092         for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2093                 if (j > i)
2094                         break;
2095                 prev_j = j;
2096         }
2097         if (prev_j == i)
2098                 return false;
2099
2100         if (prev_j == (unsigned long)-1)
2101                 bytes = (i + 1) * ctl->unit;
2102         else
2103                 bytes = (i - prev_j) * ctl->unit;
2104
2105         info->offset -= bytes;
2106         info->bytes += bytes;
2107
2108         if (update_stat)
2109                 bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2110         else
2111                 __bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2112
2113         if (!bitmap->bytes)
2114                 free_bitmap(ctl, bitmap);
2115
2116         return true;
2117 }
2118
2119 /*
2120  * We prefer always to allocate from extent entries, both for clustered and
2121  * non-clustered allocation requests. So when attempting to add a new extent
2122  * entry, try to see if there's adjacent free space in bitmap entries, and if
2123  * there is, migrate that space from the bitmaps to the extent.
2124  * Like this we get better chances of satisfying space allocation requests
2125  * because we attempt to satisfy them based on a single cache entry, and never
2126  * on 2 or more entries - even if the entries represent a contiguous free space
2127  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2128  * ends).
2129  */
2130 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2131                               struct btrfs_free_space *info,
2132                               bool update_stat)
2133 {
2134         /*
2135          * Only work with disconnected entries, as we can change their offset,
2136          * and must be extent entries.
2137          */
2138         ASSERT(!info->bitmap);
2139         ASSERT(RB_EMPTY_NODE(&info->offset_index));
2140
2141         if (ctl->total_bitmaps > 0) {
2142                 bool stole_end;
2143                 bool stole_front = false;
2144
2145                 stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2146                 if (ctl->total_bitmaps > 0)
2147                         stole_front = steal_from_bitmap_to_front(ctl, info,
2148                                                                  update_stat);
2149
2150                 if (stole_end || stole_front)
2151                         try_merge_free_space(ctl, info, update_stat);
2152         }
2153 }
2154
2155 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
2156                            u64 offset, u64 bytes)
2157 {
2158         struct btrfs_free_space *info;
2159         int ret = 0;
2160
2161         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2162         if (!info)
2163                 return -ENOMEM;
2164
2165         info->offset = offset;
2166         info->bytes = bytes;
2167         RB_CLEAR_NODE(&info->offset_index);
2168
2169         spin_lock(&ctl->tree_lock);
2170
2171         if (try_merge_free_space(ctl, info, true))
2172                 goto link;
2173
2174         /*
2175          * There was no extent directly to the left or right of this new
2176          * extent then we know we're going to have to allocate a new extent, so
2177          * before we do that see if we need to drop this into a bitmap
2178          */
2179         ret = insert_into_bitmap(ctl, info);
2180         if (ret < 0) {
2181                 goto out;
2182         } else if (ret) {
2183                 ret = 0;
2184                 goto out;
2185         }
2186 link:
2187         /*
2188          * Only steal free space from adjacent bitmaps if we're sure we're not
2189          * going to add the new free space to existing bitmap entries - because
2190          * that would mean unnecessary work that would be reverted. Therefore
2191          * attempt to steal space from bitmaps if we're adding an extent entry.
2192          */
2193         steal_from_bitmap(ctl, info, true);
2194
2195         ret = link_free_space(ctl, info);
2196         if (ret)
2197                 kmem_cache_free(btrfs_free_space_cachep, info);
2198 out:
2199         spin_unlock(&ctl->tree_lock);
2200
2201         if (ret) {
2202                 printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2203                 ASSERT(ret != -EEXIST);
2204         }
2205
2206         return ret;
2207 }
2208
2209 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2210                             u64 offset, u64 bytes)
2211 {
2212         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2213         struct btrfs_free_space *info;
2214         int ret;
2215         bool re_search = false;
2216
2217         spin_lock(&ctl->tree_lock);
2218
2219 again:
2220         ret = 0;
2221         if (!bytes)
2222                 goto out_lock;
2223
2224         info = tree_search_offset(ctl, offset, 0, 0);
2225         if (!info) {
2226                 /*
2227                  * oops didn't find an extent that matched the space we wanted
2228                  * to remove, look for a bitmap instead
2229                  */
2230                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2231                                           1, 0);
2232                 if (!info) {
2233                         /*
2234                          * If we found a partial bit of our free space in a
2235                          * bitmap but then couldn't find the other part this may
2236                          * be a problem, so WARN about it.
2237                          */
2238                         WARN_ON(re_search);
2239                         goto out_lock;
2240                 }
2241         }
2242
2243         re_search = false;
2244         if (!info->bitmap) {
2245                 unlink_free_space(ctl, info);
2246                 if (offset == info->offset) {
2247                         u64 to_free = min(bytes, info->bytes);
2248
2249                         info->bytes -= to_free;
2250                         info->offset += to_free;
2251                         if (info->bytes) {
2252                                 ret = link_free_space(ctl, info);
2253                                 WARN_ON(ret);
2254                         } else {
2255                                 kmem_cache_free(btrfs_free_space_cachep, info);
2256                         }
2257
2258                         offset += to_free;
2259                         bytes -= to_free;
2260                         goto again;
2261                 } else {
2262                         u64 old_end = info->bytes + info->offset;
2263
2264                         info->bytes = offset - info->offset;
2265                         ret = link_free_space(ctl, info);
2266                         WARN_ON(ret);
2267                         if (ret)
2268                                 goto out_lock;
2269
2270                         /* Not enough bytes in this entry to satisfy us */
2271                         if (old_end < offset + bytes) {
2272                                 bytes -= old_end - offset;
2273                                 offset = old_end;
2274                                 goto again;
2275                         } else if (old_end == offset + bytes) {
2276                                 /* all done */
2277                                 goto out_lock;
2278                         }
2279                         spin_unlock(&ctl->tree_lock);
2280
2281                         ret = btrfs_add_free_space(block_group, offset + bytes,
2282                                                    old_end - (offset + bytes));
2283                         WARN_ON(ret);
2284                         goto out;
2285                 }
2286         }
2287
2288         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2289         if (ret == -EAGAIN) {
2290                 re_search = true;
2291                 goto again;
2292         }
2293 out_lock:
2294         spin_unlock(&ctl->tree_lock);
2295 out:
2296         return ret;
2297 }
2298
2299 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2300                            u64 bytes)
2301 {
2302         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2303         struct btrfs_free_space *info;
2304         struct rb_node *n;
2305         int count = 0;
2306
2307         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2308                 info = rb_entry(n, struct btrfs_free_space, offset_index);
2309                 if (info->bytes >= bytes && !block_group->ro)
2310                         count++;
2311                 btrfs_crit(block_group->fs_info,
2312                            "entry offset %llu, bytes %llu, bitmap %s",
2313                            info->offset, info->bytes,
2314                        (info->bitmap) ? "yes" : "no");
2315         }
2316         btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2317                list_empty(&block_group->cluster_list) ? "no" : "yes");
2318         btrfs_info(block_group->fs_info,
2319                    "%d blocks of free space at or bigger than bytes is", count);
2320 }
2321
2322 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2323 {
2324         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2325
2326         spin_lock_init(&ctl->tree_lock);
2327         ctl->unit = block_group->sectorsize;
2328         ctl->start = block_group->key.objectid;
2329         ctl->private = block_group;
2330         ctl->op = &free_space_op;
2331         INIT_LIST_HEAD(&ctl->trimming_ranges);
2332         mutex_init(&ctl->cache_writeout_mutex);
2333
2334         /*
2335          * we only want to have 32k of ram per block group for keeping
2336          * track of free space, and if we pass 1/2 of that we want to
2337          * start converting things over to using bitmaps
2338          */
2339         ctl->extents_thresh = ((1024 * 32) / 2) /
2340                                 sizeof(struct btrfs_free_space);
2341 }
2342
2343 /*
2344  * for a given cluster, put all of its extents back into the free
2345  * space cache.  If the block group passed doesn't match the block group
2346  * pointed to by the cluster, someone else raced in and freed the
2347  * cluster already.  In that case, we just return without changing anything
2348  */
2349 static int
2350 __btrfs_return_cluster_to_free_space(
2351                              struct btrfs_block_group_cache *block_group,
2352                              struct btrfs_free_cluster *cluster)
2353 {
2354         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2355         struct btrfs_free_space *entry;
2356         struct rb_node *node;
2357
2358         spin_lock(&cluster->lock);
2359         if (cluster->block_group != block_group)
2360                 goto out;
2361
2362         cluster->block_group = NULL;
2363         cluster->window_start = 0;
2364         list_del_init(&cluster->block_group_list);
2365
2366         node = rb_first(&cluster->root);
2367         while (node) {
2368                 bool bitmap;
2369
2370                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2371                 node = rb_next(&entry->offset_index);
2372                 rb_erase(&entry->offset_index, &cluster->root);
2373                 RB_CLEAR_NODE(&entry->offset_index);
2374
2375                 bitmap = (entry->bitmap != NULL);
2376                 if (!bitmap) {
2377                         try_merge_free_space(ctl, entry, false);
2378                         steal_from_bitmap(ctl, entry, false);
2379                 }
2380                 tree_insert_offset(&ctl->free_space_offset,
2381                                    entry->offset, &entry->offset_index, bitmap);
2382         }
2383         cluster->root = RB_ROOT;
2384
2385 out:
2386         spin_unlock(&cluster->lock);
2387         btrfs_put_block_group(block_group);
2388         return 0;
2389 }
2390
2391 static void __btrfs_remove_free_space_cache_locked(
2392                                 struct btrfs_free_space_ctl *ctl)
2393 {
2394         struct btrfs_free_space *info;
2395         struct rb_node *node;
2396
2397         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2398                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2399                 if (!info->bitmap) {
2400                         unlink_free_space(ctl, info);
2401                         kmem_cache_free(btrfs_free_space_cachep, info);
2402                 } else {
2403                         free_bitmap(ctl, info);
2404                 }
2405
2406                 cond_resched_lock(&ctl->tree_lock);
2407         }
2408 }
2409
2410 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2411 {
2412         spin_lock(&ctl->tree_lock);
2413         __btrfs_remove_free_space_cache_locked(ctl);
2414         spin_unlock(&ctl->tree_lock);
2415 }
2416
2417 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2418 {
2419         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2420         struct btrfs_free_cluster *cluster;
2421         struct list_head *head;
2422
2423         spin_lock(&ctl->tree_lock);
2424         while ((head = block_group->cluster_list.next) !=
2425                &block_group->cluster_list) {
2426                 cluster = list_entry(head, struct btrfs_free_cluster,
2427                                      block_group_list);
2428
2429                 WARN_ON(cluster->block_group != block_group);
2430                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2431
2432                 cond_resched_lock(&ctl->tree_lock);
2433         }
2434         __btrfs_remove_free_space_cache_locked(ctl);
2435         spin_unlock(&ctl->tree_lock);
2436
2437 }
2438
2439 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2440                                u64 offset, u64 bytes, u64 empty_size,
2441                                u64 *max_extent_size)
2442 {
2443         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2444         struct btrfs_free_space *entry = NULL;
2445         u64 bytes_search = bytes + empty_size;
2446         u64 ret = 0;
2447         u64 align_gap = 0;
2448         u64 align_gap_len = 0;
2449
2450         spin_lock(&ctl->tree_lock);
2451         entry = find_free_space(ctl, &offset, &bytes_search,
2452                                 block_group->full_stripe_len, max_extent_size);
2453         if (!entry)
2454                 goto out;
2455
2456         ret = offset;
2457         if (entry->bitmap) {
2458                 bitmap_clear_bits(ctl, entry, offset, bytes);
2459                 if (!entry->bytes)
2460                         free_bitmap(ctl, entry);
2461         } else {
2462                 unlink_free_space(ctl, entry);
2463                 align_gap_len = offset - entry->offset;
2464                 align_gap = entry->offset;
2465
2466                 entry->offset = offset + bytes;
2467                 WARN_ON(entry->bytes < bytes + align_gap_len);
2468
2469                 entry->bytes -= bytes + align_gap_len;
2470                 if (!entry->bytes)
2471                         kmem_cache_free(btrfs_free_space_cachep, entry);
2472                 else
2473                         link_free_space(ctl, entry);
2474         }
2475 out:
2476         spin_unlock(&ctl->tree_lock);
2477
2478         if (align_gap_len)
2479                 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2480         return ret;
2481 }
2482
2483 /*
2484  * given a cluster, put all of its extents back into the free space
2485  * cache.  If a block group is passed, this function will only free
2486  * a cluster that belongs to the passed block group.
2487  *
2488  * Otherwise, it'll get a reference on the block group pointed to by the
2489  * cluster and remove the cluster from it.
2490  */
2491 int btrfs_return_cluster_to_free_space(
2492                                struct btrfs_block_group_cache *block_group,
2493                                struct btrfs_free_cluster *cluster)
2494 {
2495         struct btrfs_free_space_ctl *ctl;
2496         int ret;
2497
2498         /* first, get a safe pointer to the block group */
2499         spin_lock(&cluster->lock);
2500         if (!block_group) {
2501                 block_group = cluster->block_group;
2502                 if (!block_group) {
2503                         spin_unlock(&cluster->lock);
2504                         return 0;
2505                 }
2506         } else if (cluster->block_group != block_group) {
2507                 /* someone else has already freed it don't redo their work */
2508                 spin_unlock(&cluster->lock);
2509                 return 0;
2510         }
2511         atomic_inc(&block_group->count);
2512         spin_unlock(&cluster->lock);
2513
2514         ctl = block_group->free_space_ctl;
2515
2516         /* now return any extents the cluster had on it */
2517         spin_lock(&ctl->tree_lock);
2518         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2519         spin_unlock(&ctl->tree_lock);
2520
2521         /* finally drop our ref */
2522         btrfs_put_block_group(block_group);
2523         return ret;
2524 }
2525
2526 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2527                                    struct btrfs_free_cluster *cluster,
2528                                    struct btrfs_free_space *entry,
2529                                    u64 bytes, u64 min_start,
2530                                    u64 *max_extent_size)
2531 {
2532         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2533         int err;
2534         u64 search_start = cluster->window_start;
2535         u64 search_bytes = bytes;
2536         u64 ret = 0;
2537
2538         search_start = min_start;
2539         search_bytes = bytes;
2540
2541         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2542         if (err) {
2543                 if (search_bytes > *max_extent_size)
2544                         *max_extent_size = search_bytes;
2545                 return 0;
2546         }
2547
2548         ret = search_start;
2549         __bitmap_clear_bits(ctl, entry, ret, bytes);
2550
2551         return ret;
2552 }
2553
2554 /*
2555  * given a cluster, try to allocate 'bytes' from it, returns 0
2556  * if it couldn't find anything suitably large, or a logical disk offset
2557  * if things worked out
2558  */
2559 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2560                              struct btrfs_free_cluster *cluster, u64 bytes,
2561                              u64 min_start, u64 *max_extent_size)
2562 {
2563         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2564         struct btrfs_free_space *entry = NULL;
2565         struct rb_node *node;
2566         u64 ret = 0;
2567
2568         spin_lock(&cluster->lock);
2569         if (bytes > cluster->max_size)
2570                 goto out;
2571
2572         if (cluster->block_group != block_group)
2573                 goto out;
2574
2575         node = rb_first(&cluster->root);
2576         if (!node)
2577                 goto out;
2578
2579         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2580         while (1) {
2581                 if (entry->bytes < bytes && entry->bytes > *max_extent_size)
2582                         *max_extent_size = entry->bytes;
2583
2584                 if (entry->bytes < bytes ||
2585                     (!entry->bitmap && entry->offset < min_start)) {
2586                         node = rb_next(&entry->offset_index);
2587                         if (!node)
2588                                 break;
2589                         entry = rb_entry(node, struct btrfs_free_space,
2590                                          offset_index);
2591                         continue;
2592                 }
2593
2594                 if (entry->bitmap) {
2595                         ret = btrfs_alloc_from_bitmap(block_group,
2596                                                       cluster, entry, bytes,
2597                                                       cluster->window_start,
2598                                                       max_extent_size);
2599                         if (ret == 0) {
2600                                 node = rb_next(&entry->offset_index);
2601                                 if (!node)
2602                                         break;
2603                                 entry = rb_entry(node, struct btrfs_free_space,
2604                                                  offset_index);
2605                                 continue;
2606                         }
2607                         cluster->window_start += bytes;
2608                 } else {
2609                         ret = entry->offset;
2610
2611                         entry->offset += bytes;
2612                         entry->bytes -= bytes;
2613                 }
2614
2615                 if (entry->bytes == 0)
2616                         rb_erase(&entry->offset_index, &cluster->root);
2617                 break;
2618         }
2619 out:
2620         spin_unlock(&cluster->lock);
2621
2622         if (!ret)
2623                 return 0;
2624
2625         spin_lock(&ctl->tree_lock);
2626
2627         ctl->free_space -= bytes;
2628         if (entry->bytes == 0) {
2629                 ctl->free_extents--;
2630                 if (entry->bitmap) {
2631                         kfree(entry->bitmap);
2632                         ctl->total_bitmaps--;
2633                         ctl->op->recalc_thresholds(ctl);
2634                 }
2635                 kmem_cache_free(btrfs_free_space_cachep, entry);
2636         }
2637
2638         spin_unlock(&ctl->tree_lock);
2639
2640         return ret;
2641 }
2642
2643 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2644                                 struct btrfs_free_space *entry,
2645                                 struct btrfs_free_cluster *cluster,
2646                                 u64 offset, u64 bytes,
2647                                 u64 cont1_bytes, u64 min_bytes)
2648 {
2649         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2650         unsigned long next_zero;
2651         unsigned long i;
2652         unsigned long want_bits;
2653         unsigned long min_bits;
2654         unsigned long found_bits;
2655         unsigned long start = 0;
2656         unsigned long total_found = 0;
2657         int ret;
2658
2659         i = offset_to_bit(entry->offset, ctl->unit,
2660                           max_t(u64, offset, entry->offset));
2661         want_bits = bytes_to_bits(bytes, ctl->unit);
2662         min_bits = bytes_to_bits(min_bytes, ctl->unit);
2663
2664 again:
2665         found_bits = 0;
2666         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2667                 next_zero = find_next_zero_bit(entry->bitmap,
2668                                                BITS_PER_BITMAP, i);
2669                 if (next_zero - i >= min_bits) {
2670                         found_bits = next_zero - i;
2671                         break;
2672                 }
2673                 i = next_zero;
2674         }
2675
2676         if (!found_bits)
2677                 return -ENOSPC;
2678
2679         if (!total_found) {
2680                 start = i;
2681                 cluster->max_size = 0;
2682         }
2683
2684         total_found += found_bits;
2685
2686         if (cluster->max_size < found_bits * ctl->unit)
2687                 cluster->max_size = found_bits * ctl->unit;
2688
2689         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2690                 i = next_zero + 1;
2691                 goto again;
2692         }
2693
2694         cluster->window_start = start * ctl->unit + entry->offset;
2695         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2696         ret = tree_insert_offset(&cluster->root, entry->offset,
2697                                  &entry->offset_index, 1);
2698         ASSERT(!ret); /* -EEXIST; Logic error */
2699
2700         trace_btrfs_setup_cluster(block_group, cluster,
2701                                   total_found * ctl->unit, 1);
2702         return 0;
2703 }
2704
2705 /*
2706  * This searches the block group for just extents to fill the cluster with.
2707  * Try to find a cluster with at least bytes total bytes, at least one
2708  * extent of cont1_bytes, and other clusters of at least min_bytes.
2709  */
2710 static noinline int
2711 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2712                         struct btrfs_free_cluster *cluster,
2713                         struct list_head *bitmaps, u64 offset, u64 bytes,
2714                         u64 cont1_bytes, u64 min_bytes)
2715 {
2716         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2717         struct btrfs_free_space *first = NULL;
2718         struct btrfs_free_space *entry = NULL;
2719         struct btrfs_free_space *last;
2720         struct rb_node *node;
2721         u64 window_free;
2722         u64 max_extent;
2723         u64 total_size = 0;
2724
2725         entry = tree_search_offset(ctl, offset, 0, 1);
2726         if (!entry)
2727                 return -ENOSPC;
2728
2729         /*
2730          * We don't want bitmaps, so just move along until we find a normal
2731          * extent entry.
2732          */
2733         while (entry->bitmap || entry->bytes < min_bytes) {
2734                 if (entry->bitmap && list_empty(&entry->list))
2735                         list_add_tail(&entry->list, bitmaps);
2736                 node = rb_next(&entry->offset_index);
2737                 if (!node)
2738                         return -ENOSPC;
2739                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2740         }
2741
2742         window_free = entry->bytes;
2743         max_extent = entry->bytes;
2744         first = entry;
2745         last = entry;
2746
2747         for (node = rb_next(&entry->offset_index); node;
2748              node = rb_next(&entry->offset_index)) {
2749                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2750
2751                 if (entry->bitmap) {
2752                         if (list_empty(&entry->list))
2753                                 list_add_tail(&entry->list, bitmaps);
2754                         continue;
2755                 }
2756
2757                 if (entry->bytes < min_bytes)
2758                         continue;
2759
2760                 last = entry;
2761                 window_free += entry->bytes;
2762                 if (entry->bytes > max_extent)
2763                         max_extent = entry->bytes;
2764         }
2765
2766         if (window_free < bytes || max_extent < cont1_bytes)
2767                 return -ENOSPC;
2768
2769         cluster->window_start = first->offset;
2770
2771         node = &first->offset_index;
2772
2773         /*
2774          * now we've found our entries, pull them out of the free space
2775          * cache and put them into the cluster rbtree
2776          */
2777         do {
2778                 int ret;
2779
2780                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2781                 node = rb_next(&entry->offset_index);
2782                 if (entry->bitmap || entry->bytes < min_bytes)
2783                         continue;
2784
2785                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2786                 ret = tree_insert_offset(&cluster->root, entry->offset,
2787                                          &entry->offset_index, 0);
2788                 total_size += entry->bytes;
2789                 ASSERT(!ret); /* -EEXIST; Logic error */
2790         } while (node && entry != last);
2791
2792         cluster->max_size = max_extent;
2793         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2794         return 0;
2795 }
2796
2797 /*
2798  * This specifically looks for bitmaps that may work in the cluster, we assume
2799  * that we have already failed to find extents that will work.
2800  */
2801 static noinline int
2802 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2803                      struct btrfs_free_cluster *cluster,
2804                      struct list_head *bitmaps, u64 offset, u64 bytes,
2805                      u64 cont1_bytes, u64 min_bytes)
2806 {
2807         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2808         struct btrfs_free_space *entry;
2809         int ret = -ENOSPC;
2810         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2811
2812         if (ctl->total_bitmaps == 0)
2813                 return -ENOSPC;
2814
2815         /*
2816          * The bitmap that covers offset won't be in the list unless offset
2817          * is just its start offset.
2818          */
2819         entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2820         if (entry->offset != bitmap_offset) {
2821                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2822                 if (entry && list_empty(&entry->list))
2823                         list_add(&entry->list, bitmaps);
2824         }
2825
2826         list_for_each_entry(entry, bitmaps, list) {
2827                 if (entry->bytes < bytes)
2828                         continue;
2829                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2830                                            bytes, cont1_bytes, min_bytes);
2831                 if (!ret)
2832                         return 0;
2833         }
2834
2835         /*
2836          * The bitmaps list has all the bitmaps that record free space
2837          * starting after offset, so no more search is required.
2838          */
2839         return -ENOSPC;
2840 }
2841
2842 /*
2843  * here we try to find a cluster of blocks in a block group.  The goal
2844  * is to find at least bytes+empty_size.
2845  * We might not find them all in one contiguous area.
2846  *
2847  * returns zero and sets up cluster if things worked out, otherwise
2848  * it returns -enospc
2849  */
2850 int btrfs_find_space_cluster(struct btrfs_root *root,
2851                              struct btrfs_block_group_cache *block_group,
2852                              struct btrfs_free_cluster *cluster,
2853                              u64 offset, u64 bytes, u64 empty_size)
2854 {
2855         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2856         struct btrfs_free_space *entry, *tmp;
2857         LIST_HEAD(bitmaps);
2858         u64 min_bytes;
2859         u64 cont1_bytes;
2860         int ret;
2861
2862         /*
2863          * Choose the minimum extent size we'll require for this
2864          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2865          * For metadata, allow allocates with smaller extents.  For
2866          * data, keep it dense.
2867          */
2868         if (btrfs_test_opt(root, SSD_SPREAD)) {
2869                 cont1_bytes = min_bytes = bytes + empty_size;
2870         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2871                 cont1_bytes = bytes;
2872                 min_bytes = block_group->sectorsize;
2873         } else {
2874                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2875                 min_bytes = block_group->sectorsize;
2876         }
2877
2878         spin_lock(&ctl->tree_lock);
2879
2880         /*
2881          * If we know we don't have enough space to make a cluster don't even
2882          * bother doing all the work to try and find one.
2883          */
2884         if (ctl->free_space < bytes) {
2885                 spin_unlock(&ctl->tree_lock);
2886                 return -ENOSPC;
2887         }
2888
2889         spin_lock(&cluster->lock);
2890
2891         /* someone already found a cluster, hooray */
2892         if (cluster->block_group) {
2893                 ret = 0;
2894                 goto out;
2895         }
2896
2897         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2898                                  min_bytes);
2899
2900         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2901                                       bytes + empty_size,
2902                                       cont1_bytes, min_bytes);
2903         if (ret)
2904                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2905                                            offset, bytes + empty_size,
2906                                            cont1_bytes, min_bytes);
2907
2908         /* Clear our temporary list */
2909         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2910                 list_del_init(&entry->list);
2911
2912         if (!ret) {
2913                 atomic_inc(&block_group->count);
2914                 list_add_tail(&cluster->block_group_list,
2915                               &block_group->cluster_list);
2916                 cluster->block_group = block_group;
2917         } else {
2918                 trace_btrfs_failed_cluster_setup(block_group);
2919         }
2920 out:
2921         spin_unlock(&cluster->lock);
2922         spin_unlock(&ctl->tree_lock);
2923
2924         return ret;
2925 }
2926
2927 /*
2928  * simple code to zero out a cluster
2929  */
2930 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2931 {
2932         spin_lock_init(&cluster->lock);
2933         spin_lock_init(&cluster->refill_lock);
2934         cluster->root = RB_ROOT;
2935         cluster->max_size = 0;
2936         INIT_LIST_HEAD(&cluster->block_group_list);
2937         cluster->block_group = NULL;
2938 }
2939
2940 static int do_trimming(struct btrfs_block_group_cache *block_group,
2941                        u64 *total_trimmed, u64 start, u64 bytes,
2942                        u64 reserved_start, u64 reserved_bytes,
2943                        struct btrfs_trim_range *trim_entry)
2944 {
2945         struct btrfs_space_info *space_info = block_group->space_info;
2946         struct btrfs_fs_info *fs_info = block_group->fs_info;
2947         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2948         int ret;
2949         int update = 0;
2950         u64 trimmed = 0;
2951
2952         spin_lock(&space_info->lock);
2953         spin_lock(&block_group->lock);
2954         if (!block_group->ro) {
2955                 block_group->reserved += reserved_bytes;
2956                 space_info->bytes_reserved += reserved_bytes;
2957                 update = 1;
2958         }
2959         spin_unlock(&block_group->lock);
2960         spin_unlock(&space_info->lock);
2961
2962         ret = btrfs_discard_extent(fs_info->extent_root,
2963                                    start, bytes, &trimmed);
2964         if (!ret)
2965                 *total_trimmed += trimmed;
2966
2967         mutex_lock(&ctl->cache_writeout_mutex);
2968         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2969         list_del(&trim_entry->list);
2970         mutex_unlock(&ctl->cache_writeout_mutex);
2971
2972         if (update) {
2973                 spin_lock(&space_info->lock);
2974                 spin_lock(&block_group->lock);
2975                 if (block_group->ro)
2976                         space_info->bytes_readonly += reserved_bytes;
2977                 block_group->reserved -= reserved_bytes;
2978                 space_info->bytes_reserved -= reserved_bytes;
2979                 spin_unlock(&space_info->lock);
2980                 spin_unlock(&block_group->lock);
2981         }
2982
2983         return ret;
2984 }
2985
2986 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2987                           u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2988 {
2989         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2990         struct btrfs_free_space *entry;
2991         struct rb_node *node;
2992         int ret = 0;
2993         u64 extent_start;
2994         u64 extent_bytes;
2995         u64 bytes;
2996
2997         while (start < end) {
2998                 struct btrfs_trim_range trim_entry;
2999
3000                 mutex_lock(&ctl->cache_writeout_mutex);
3001                 spin_lock(&ctl->tree_lock);
3002
3003                 if (ctl->free_space < minlen) {
3004                         spin_unlock(&ctl->tree_lock);
3005                         mutex_unlock(&ctl->cache_writeout_mutex);
3006                         break;
3007                 }
3008
3009                 entry = tree_search_offset(ctl, start, 0, 1);
3010                 if (!entry) {
3011                         spin_unlock(&ctl->tree_lock);
3012                         mutex_unlock(&ctl->cache_writeout_mutex);
3013                         break;
3014                 }
3015
3016                 /* skip bitmaps */
3017                 while (entry->bitmap) {
3018                         node = rb_next(&entry->offset_index);
3019                         if (!node) {
3020                                 spin_unlock(&ctl->tree_lock);
3021                                 mutex_unlock(&ctl->cache_writeout_mutex);
3022                                 goto out;
3023                         }
3024                         entry = rb_entry(node, struct btrfs_free_space,
3025                                          offset_index);
3026                 }
3027
3028                 if (entry->offset >= end) {
3029                         spin_unlock(&ctl->tree_lock);
3030                         mutex_unlock(&ctl->cache_writeout_mutex);
3031                         break;
3032                 }
3033
3034                 extent_start = entry->offset;
3035                 extent_bytes = entry->bytes;
3036                 start = max(start, extent_start);
3037                 bytes = min(extent_start + extent_bytes, end) - start;
3038                 if (bytes < minlen) {
3039                         spin_unlock(&ctl->tree_lock);
3040                         mutex_unlock(&ctl->cache_writeout_mutex);
3041                         goto next;
3042                 }
3043
3044                 unlink_free_space(ctl, entry);
3045                 kmem_cache_free(btrfs_free_space_cachep, entry);
3046
3047                 spin_unlock(&ctl->tree_lock);
3048                 trim_entry.start = extent_start;
3049                 trim_entry.bytes = extent_bytes;
3050                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3051                 mutex_unlock(&ctl->cache_writeout_mutex);
3052
3053                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3054                                   extent_start, extent_bytes, &trim_entry);
3055                 if (ret)
3056                         break;
3057 next:
3058                 start += bytes;
3059
3060                 if (fatal_signal_pending(current)) {
3061                         ret = -ERESTARTSYS;
3062                         break;
3063                 }
3064
3065                 cond_resched();
3066         }
3067 out:
3068         return ret;
3069 }
3070
3071 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
3072                         u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3073 {
3074         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3075         struct btrfs_free_space *entry;
3076         int ret = 0;
3077         int ret2;
3078         u64 bytes;
3079         u64 offset = offset_to_bitmap(ctl, start);
3080
3081         while (offset < end) {
3082                 bool next_bitmap = false;
3083                 struct btrfs_trim_range trim_entry;
3084
3085                 mutex_lock(&ctl->cache_writeout_mutex);
3086                 spin_lock(&ctl->tree_lock);
3087
3088                 if (ctl->free_space < minlen) {
3089                         spin_unlock(&ctl->tree_lock);
3090                         mutex_unlock(&ctl->cache_writeout_mutex);
3091                         break;
3092                 }
3093
3094                 entry = tree_search_offset(ctl, offset, 1, 0);
3095                 if (!entry) {
3096                         spin_unlock(&ctl->tree_lock);
3097                         mutex_unlock(&ctl->cache_writeout_mutex);
3098                         next_bitmap = true;
3099                         goto next;
3100                 }
3101
3102                 bytes = minlen;
3103                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
3104                 if (ret2 || start >= end) {
3105                         spin_unlock(&ctl->tree_lock);
3106                         mutex_unlock(&ctl->cache_writeout_mutex);
3107                         next_bitmap = true;
3108                         goto next;
3109                 }
3110
3111                 bytes = min(bytes, end - start);
3112                 if (bytes < minlen) {
3113                         spin_unlock(&ctl->tree_lock);
3114                         mutex_unlock(&ctl->cache_writeout_mutex);
3115                         goto next;
3116                 }
3117
3118                 bitmap_clear_bits(ctl, entry, start, bytes);
3119                 if (entry->bytes == 0)
3120                         free_bitmap(ctl, entry);
3121
3122                 spin_unlock(&ctl->tree_lock);
3123                 trim_entry.start = start;
3124                 trim_entry.bytes = bytes;
3125                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3126                 mutex_unlock(&ctl->cache_writeout_mutex);
3127
3128                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3129                                   start, bytes, &trim_entry);
3130                 if (ret)
3131                         break;
3132 next:
3133                 if (next_bitmap) {
3134                         offset += BITS_PER_BITMAP * ctl->unit;
3135                 } else {
3136                         start += bytes;
3137                         if (start >= offset + BITS_PER_BITMAP * ctl->unit)
3138                                 offset += BITS_PER_BITMAP * ctl->unit;
3139                 }
3140
3141                 if (fatal_signal_pending(current)) {
3142                         ret = -ERESTARTSYS;
3143                         break;
3144                 }
3145
3146                 cond_resched();
3147         }
3148
3149         return ret;
3150 }
3151
3152 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
3153                            u64 *trimmed, u64 start, u64 end, u64 minlen)
3154 {
3155         int ret;
3156
3157         *trimmed = 0;
3158
3159         spin_lock(&block_group->lock);
3160         if (block_group->removed) {
3161                 spin_unlock(&block_group->lock);
3162                 return 0;
3163         }
3164         atomic_inc(&block_group->trimming);
3165         spin_unlock(&block_group->lock);
3166
3167         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
3168         if (ret)
3169                 goto out;
3170
3171         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
3172 out:
3173         spin_lock(&block_group->lock);
3174         if (atomic_dec_and_test(&block_group->trimming) &&
3175             block_group->removed) {
3176                 struct extent_map_tree *em_tree;
3177                 struct extent_map *em;
3178
3179                 spin_unlock(&block_group->lock);
3180
3181                 lock_chunks(block_group->fs_info->chunk_root);
3182                 em_tree = &block_group->fs_info->mapping_tree.map_tree;
3183                 write_lock(&em_tree->lock);
3184                 em = lookup_extent_mapping(em_tree, block_group->key.objectid,
3185                                            1);
3186                 BUG_ON(!em); /* logic error, can't happen */
3187                 /*
3188                  * remove_extent_mapping() will delete us from the pinned_chunks
3189                  * list, which is protected by the chunk mutex.
3190                  */
3191                 remove_extent_mapping(em_tree, em);
3192                 write_unlock(&em_tree->lock);
3193                 unlock_chunks(block_group->fs_info->chunk_root);
3194
3195                 /* once for us and once for the tree */
3196                 free_extent_map(em);
3197                 free_extent_map(em);
3198
3199                 /*
3200                  * We've left one free space entry and other tasks trimming
3201                  * this block group have left 1 entry each one. Free them.
3202                  */
3203                 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3204         } else {
3205                 spin_unlock(&block_group->lock);
3206         }
3207
3208         return ret;
3209 }
3210
3211 /*
3212  * Find the left-most item in the cache tree, and then return the
3213  * smallest inode number in the item.
3214  *
3215  * Note: the returned inode number may not be the smallest one in
3216  * the tree, if the left-most item is a bitmap.
3217  */
3218 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
3219 {
3220         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
3221         struct btrfs_free_space *entry = NULL;
3222         u64 ino = 0;
3223
3224         spin_lock(&ctl->tree_lock);
3225
3226         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
3227                 goto out;
3228
3229         entry = rb_entry(rb_first(&ctl->free_space_offset),
3230                          struct btrfs_free_space, offset_index);
3231
3232         if (!entry->bitmap) {
3233                 ino = entry->offset;
3234
3235                 unlink_free_space(ctl, entry);
3236                 entry->offset++;
3237                 entry->bytes--;
3238                 if (!entry->bytes)
3239                         kmem_cache_free(btrfs_free_space_cachep, entry);
3240                 else
3241                         link_free_space(ctl, entry);
3242         } else {
3243                 u64 offset = 0;
3244                 u64 count = 1;
3245                 int ret;
3246
3247                 ret = search_bitmap(ctl, entry, &offset, &count);
3248                 /* Logic error; Should be empty if it can't find anything */
3249                 ASSERT(!ret);
3250
3251                 ino = offset;
3252                 bitmap_clear_bits(ctl, entry, offset, 1);
3253                 if (entry->bytes == 0)
3254                         free_bitmap(ctl, entry);
3255         }
3256 out:
3257         spin_unlock(&ctl->tree_lock);
3258
3259         return ino;
3260 }
3261
3262 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3263                                     struct btrfs_path *path)
3264 {
3265         struct inode *inode = NULL;
3266
3267         spin_lock(&root->ino_cache_lock);
3268         if (root->ino_cache_inode)
3269                 inode = igrab(root->ino_cache_inode);
3270         spin_unlock(&root->ino_cache_lock);
3271         if (inode)
3272                 return inode;
3273
3274         inode = __lookup_free_space_inode(root, path, 0);
3275         if (IS_ERR(inode))
3276                 return inode;
3277
3278         spin_lock(&root->ino_cache_lock);
3279         if (!btrfs_fs_closing(root->fs_info))
3280                 root->ino_cache_inode = igrab(inode);
3281         spin_unlock(&root->ino_cache_lock);
3282
3283         return inode;
3284 }
3285
3286 int create_free_ino_inode(struct btrfs_root *root,
3287                           struct btrfs_trans_handle *trans,
3288                           struct btrfs_path *path)
3289 {
3290         return __create_free_space_inode(root, trans, path,
3291                                          BTRFS_FREE_INO_OBJECTID, 0);
3292 }
3293
3294 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3295 {
3296         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3297         struct btrfs_path *path;
3298         struct inode *inode;
3299         int ret = 0;
3300         u64 root_gen = btrfs_root_generation(&root->root_item);
3301
3302         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3303                 return 0;
3304
3305         /*
3306          * If we're unmounting then just return, since this does a search on the
3307          * normal root and not the commit root and we could deadlock.
3308          */
3309         if (btrfs_fs_closing(fs_info))
3310                 return 0;
3311
3312         path = btrfs_alloc_path();
3313         if (!path)
3314                 return 0;
3315
3316         inode = lookup_free_ino_inode(root, path);
3317         if (IS_ERR(inode))
3318                 goto out;
3319
3320         if (root_gen != BTRFS_I(inode)->generation)
3321                 goto out_put;
3322
3323         ret = __load_free_space_cache(root, inode, ctl, path, 0);
3324
3325         if (ret < 0)
3326                 btrfs_err(fs_info,
3327                         "failed to load free ino cache for root %llu",
3328                         root->root_key.objectid);
3329 out_put:
3330         iput(inode);
3331 out:
3332         btrfs_free_path(path);
3333         return ret;
3334 }
3335
3336 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3337                               struct btrfs_trans_handle *trans,
3338                               struct btrfs_path *path,
3339                               struct inode *inode)
3340 {
3341         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3342         int ret;
3343
3344         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3345                 return 0;
3346
3347         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
3348         if (ret) {
3349                 btrfs_delalloc_release_metadata(inode, inode->i_size);
3350 #ifdef DEBUG
3351                 btrfs_err(root->fs_info,
3352                         "failed to write free ino cache for root %llu",
3353                         root->root_key.objectid);
3354 #endif
3355         }
3356
3357         return ret;
3358 }
3359
3360 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3361 /*
3362  * Use this if you need to make a bitmap or extent entry specifically, it
3363  * doesn't do any of the merging that add_free_space does, this acts a lot like
3364  * how the free space cache loading stuff works, so you can get really weird
3365  * configurations.
3366  */
3367 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3368                               u64 offset, u64 bytes, bool bitmap)
3369 {
3370         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3371         struct btrfs_free_space *info = NULL, *bitmap_info;
3372         void *map = NULL;
3373         u64 bytes_added;
3374         int ret;
3375
3376 again:
3377         if (!info) {
3378                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3379                 if (!info)
3380                         return -ENOMEM;
3381         }
3382
3383         if (!bitmap) {
3384                 spin_lock(&ctl->tree_lock);
3385                 info->offset = offset;
3386                 info->bytes = bytes;
3387                 ret = link_free_space(ctl, info);
3388                 spin_unlock(&ctl->tree_lock);
3389                 if (ret)
3390                         kmem_cache_free(btrfs_free_space_cachep, info);
3391                 return ret;
3392         }
3393
3394         if (!map) {
3395                 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3396                 if (!map) {
3397                         kmem_cache_free(btrfs_free_space_cachep, info);
3398                         return -ENOMEM;
3399                 }
3400         }
3401
3402         spin_lock(&ctl->tree_lock);
3403         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3404                                          1, 0);
3405         if (!bitmap_info) {
3406                 info->bitmap = map;
3407                 map = NULL;
3408                 add_new_bitmap(ctl, info, offset);
3409                 bitmap_info = info;
3410                 info = NULL;
3411         }
3412
3413         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3414         bytes -= bytes_added;
3415         offset += bytes_added;
3416         spin_unlock(&ctl->tree_lock);
3417
3418         if (bytes)
3419                 goto again;
3420
3421         if (info)
3422                 kmem_cache_free(btrfs_free_space_cachep, info);
3423         if (map)
3424                 kfree(map);
3425         return 0;
3426 }
3427
3428 /*
3429  * Checks to see if the given range is in the free space cache.  This is really
3430  * just used to check the absence of space, so if there is free space in the
3431  * range at all we will return 1.
3432  */
3433 int test_check_exists(struct btrfs_block_group_cache *cache,
3434                       u64 offset, u64 bytes)
3435 {
3436         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3437         struct btrfs_free_space *info;
3438         int ret = 0;
3439
3440         spin_lock(&ctl->tree_lock);
3441         info = tree_search_offset(ctl, offset, 0, 0);
3442         if (!info) {
3443                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3444                                           1, 0);
3445                 if (!info)
3446                         goto out;
3447         }
3448
3449 have_info:
3450         if (info->bitmap) {
3451                 u64 bit_off, bit_bytes;
3452                 struct rb_node *n;
3453                 struct btrfs_free_space *tmp;
3454
3455                 bit_off = offset;
3456                 bit_bytes = ctl->unit;
3457                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3458                 if (!ret) {
3459                         if (bit_off == offset) {
3460                                 ret = 1;
3461                                 goto out;
3462                         } else if (bit_off > offset &&
3463                                    offset + bytes > bit_off) {
3464                                 ret = 1;
3465                                 goto out;
3466                         }
3467                 }
3468
3469                 n = rb_prev(&info->offset_index);
3470                 while (n) {
3471                         tmp = rb_entry(n, struct btrfs_free_space,
3472                                        offset_index);
3473                         if (tmp->offset + tmp->bytes < offset)
3474                                 break;
3475                         if (offset + bytes < tmp->offset) {
3476                                 n = rb_prev(&info->offset_index);
3477                                 continue;
3478                         }
3479                         info = tmp;
3480                         goto have_info;
3481                 }
3482
3483                 n = rb_next(&info->offset_index);
3484                 while (n) {
3485                         tmp = rb_entry(n, struct btrfs_free_space,
3486                                        offset_index);
3487                         if (offset + bytes < tmp->offset)
3488                                 break;
3489                         if (tmp->offset + tmp->bytes < offset) {
3490                                 n = rb_next(&info->offset_index);
3491                                 continue;
3492                         }
3493                         info = tmp;
3494                         goto have_info;
3495                 }
3496
3497                 ret = 0;
3498                 goto out;
3499         }
3500
3501         if (info->offset == offset) {
3502                 ret = 1;
3503                 goto out;
3504         }
3505
3506         if (offset > info->offset && offset < info->offset + info->bytes)
3507                 ret = 1;
3508 out:
3509         spin_unlock(&ctl->tree_lock);
3510         return ret;
3511 }
3512 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */