fs/btrfs/free-space-cache.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2008 Red Hat.  All rights reserved.
   4  */
   5
   6 #include <linux/pagemap.h>
   7 #include <linux/sched.h>
   8 #include <linux/sched/signal.h>
   9 #include <linux/slab.h>
  10 #include <linux/math64.h>
  11 #include <linux/ratelimit.h>
  12 #include <linux/error-injection.h>
  13 #include <linux/sched/mm.h>
  14 #include "misc.h"
  15 #include "ctree.h"
  16 #include "free-space-cache.h"
  17 #include "transaction.h"
  18 #include "disk-io.h"
  19 #include "extent_io.h"
  20 #include "volumes.h"
  21 #include "space-info.h"
  22 #include "delalloc-space.h"
  23 #include "block-group.h"
  24 #include "discard.h"
  25
  26 #define BITS_PER_BITMAP         (PAGE_SIZE * 8UL)
  27 #define MAX_CACHE_BYTES_PER_GIG SZ_64K
  28 #define FORCE_EXTENT_THRESHOLD  SZ_1M
  29
  30 struct btrfs_trim_range {
  31         u64 start;
  32         u64 bytes;
  33         struct list_head list;
  34 };
  35
  36 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  37                            struct btrfs_free_space *info);
  38 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  39                               struct btrfs_free_space *info);
  40 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
  41                          struct btrfs_free_space *bitmap_info, u64 *offset,
  42                          u64 *bytes, bool for_alloc);
  43 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
  44                         struct btrfs_free_space *bitmap_info);
  45 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
  46                               struct btrfs_free_space *info, u64 offset,
  47                               u64 bytes);
  48
  49 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  50                                                struct btrfs_path *path,
  51                                                u64 offset)
  52 {
  53         struct btrfs_fs_info *fs_info = root->fs_info;
  54         struct btrfs_key key;
  55         struct btrfs_key location;
  56         struct btrfs_disk_key disk_key;
  57         struct btrfs_free_space_header *header;
  58         struct extent_buffer *leaf;
  59         struct inode *inode = NULL;
  60         unsigned nofs_flag;
  61         int ret;
  62
  63         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  64         key.offset = offset;
  65         key.type = 0;
  66
  67         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  68         if (ret < 0)
  69                 return ERR_PTR(ret);
  70         if (ret > 0) {
  71                 btrfs_release_path(path);
  72                 return ERR_PTR(-ENOENT);
  73         }
  74
  75         leaf = path->nodes[0];
  76         header = btrfs_item_ptr(leaf, path->slots[0],
  77                                 struct btrfs_free_space_header);
  78         btrfs_free_space_key(leaf, header, &disk_key);
  79         btrfs_disk_key_to_cpu(&location, &disk_key);
  80         btrfs_release_path(path);
  81
  82         /*
  83          * We are often under a trans handle at this point, so we need to make
  84          * sure NOFS is set to keep us from deadlocking.
  85          */
  86         nofs_flag = memalloc_nofs_save();
  87         inode = btrfs_iget_path(fs_info->sb, location.objectid, root, path);
  88         btrfs_release_path(path);
  89         memalloc_nofs_restore(nofs_flag);
  90         if (IS_ERR(inode))
  91                 return inode;
  92
  93         mapping_set_gfp_mask(inode->i_mapping,
  94                         mapping_gfp_constraint(inode->i_mapping,
  95                         ~(__GFP_FS | __GFP_HIGHMEM)));
  96
  97         return inode;
  98 }
  99
 100 struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
 101                 struct btrfs_path *path)
 102 {
 103         struct btrfs_fs_info *fs_info = block_group->fs_info;
 104         struct inode *inode = NULL;
 105         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 106
 107         spin_lock(&block_group->lock);
 108         if (block_group->inode)
 109                 inode = igrab(block_group->inode);
 110         spin_unlock(&block_group->lock);
 111         if (inode)
 112                 return inode;
 113
 114         inode = __lookup_free_space_inode(fs_info->tree_root, path,
 115                                           block_group->start);
 116         if (IS_ERR(inode))
 117                 return inode;
 118
 119         spin_lock(&block_group->lock);
 120         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 121                 btrfs_info(fs_info, "Old style space inode found, converting.");
 122                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 123                         BTRFS_INODE_NODATACOW;
 124                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 125         }
 126
 127         if (!block_group->iref) {
 128                 block_group->inode = igrab(inode);
 129                 block_group->iref = 1;
 130         }
 131         spin_unlock(&block_group->lock);
 132
 133         return inode;
 134 }
 135
 136 static int __create_free_space_inode(struct btrfs_root *root,
 137                                      struct btrfs_trans_handle *trans,
 138                                      struct btrfs_path *path,
 139                                      u64 ino, u64 offset)
 140 {
 141         struct btrfs_key key;
 142         struct btrfs_disk_key disk_key;
 143         struct btrfs_free_space_header *header;
 144         struct btrfs_inode_item *inode_item;
 145         struct extent_buffer *leaf;
 146         /* We inline CRCs for the free disk space cache */
 147         const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC |
 148                           BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 149         int ret;
 150
 151         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 152         if (ret)
 153                 return ret;
 154
 155         leaf = path->nodes[0];
 156         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 157                                     struct btrfs_inode_item);
 158         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 159         memzero_extent_buffer(leaf, (unsigned long)inode_item,
 160                              sizeof(*inode_item));
 161         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 162         btrfs_set_inode_size(leaf, inode_item, 0);
 163         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 164         btrfs_set_inode_uid(leaf, inode_item, 0);
 165         btrfs_set_inode_gid(leaf, inode_item, 0);
 166         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 167         btrfs_set_inode_flags(leaf, inode_item, flags);
 168         btrfs_set_inode_nlink(leaf, inode_item, 1);
 169         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 170         btrfs_set_inode_block_group(leaf, inode_item, offset);
 171         btrfs_mark_buffer_dirty(leaf);
 172         btrfs_release_path(path);
 173
 174         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 175         key.offset = offset;
 176         key.type = 0;
 177         ret = btrfs_insert_empty_item(trans, root, path, &key,
 178                                       sizeof(struct btrfs_free_space_header));
 179         if (ret < 0) {
 180                 btrfs_release_path(path);
 181                 return ret;
 182         }
 183
 184         leaf = path->nodes[0];
 185         header = btrfs_item_ptr(leaf, path->slots[0],
 186                                 struct btrfs_free_space_header);
 187         memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
 188         btrfs_set_free_space_key(leaf, header, &disk_key);
 189         btrfs_mark_buffer_dirty(leaf);
 190         btrfs_release_path(path);
 191
 192         return 0;
 193 }
 194
 195 int create_free_space_inode(struct btrfs_trans_handle *trans,
 196                             struct btrfs_block_group *block_group,
 197                             struct btrfs_path *path)
 198 {
 199         int ret;
 200         u64 ino;
 201
 202         ret = btrfs_get_free_objectid(trans->fs_info->tree_root, &ino);
 203         if (ret < 0)
 204                 return ret;
 205
 206         return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
 207                                          ino, block_group->start);
 208 }
 209
 210 /*
 211  * inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode
 212  * handles lookup, otherwise it takes ownership and iputs the inode.
 213  * Don't reuse an inode pointer after passing it into this function.
 214  */
 215 int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans,
 216                                   struct inode *inode,
 217                                   struct btrfs_block_group *block_group)
 218 {
 219         struct btrfs_path *path;
 220         struct btrfs_key key;
 221         int ret = 0;
 222
 223         path = btrfs_alloc_path();
 224         if (!path)
 225                 return -ENOMEM;
 226
 227         if (!inode)
 228                 inode = lookup_free_space_inode(block_group, path);
 229         if (IS_ERR(inode)) {
 230                 if (PTR_ERR(inode) != -ENOENT)
 231                         ret = PTR_ERR(inode);
 232                 goto out;
 233         }
 234         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
 235         if (ret) {
 236                 btrfs_add_delayed_iput(inode);
 237                 goto out;
 238         }
 239         clear_nlink(inode);
 240         /* One for the block groups ref */
 241         spin_lock(&block_group->lock);
 242         if (block_group->iref) {
 243                 block_group->iref = 0;
 244                 block_group->inode = NULL;
 245                 spin_unlock(&block_group->lock);
 246                 iput(inode);
 247         } else {
 248                 spin_unlock(&block_group->lock);
 249         }
 250         /* One for the lookup ref */
 251         btrfs_add_delayed_iput(inode);
 252
 253         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 254         key.type = 0;
 255         key.offset = block_group->start;
 256         ret = btrfs_search_slot(trans, trans->fs_info->tree_root, &key, path,
 257                                 -1, 1);
 258         if (ret) {
 259                 if (ret > 0)
 260                         ret = 0;
 261                 goto out;
 262         }
 263         ret = btrfs_del_item(trans, trans->fs_info->tree_root, path);
 264 out:
 265         btrfs_free_path(path);
 266         return ret;
 267 }
 268
 269 int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info,
 270                                        struct btrfs_block_rsv *rsv)
 271 {
 272         u64 needed_bytes;
 273         int ret;
 274
 275         /* 1 for slack space, 1 for updating the inode */
 276         needed_bytes = btrfs_calc_insert_metadata_size(fs_info, 1) +
 277                 btrfs_calc_metadata_size(fs_info, 1);
 278
 279         spin_lock(&rsv->lock);
 280         if (rsv->reserved < needed_bytes)
 281                 ret = -ENOSPC;
 282         else
 283                 ret = 0;
 284         spin_unlock(&rsv->lock);
 285         return ret;
 286 }
 287
 288 int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
 289                                     struct btrfs_block_group *block_group,
 290                                     struct inode *inode)
 291 {
 292         struct btrfs_root *root = BTRFS_I(inode)->root;
 293         int ret = 0;
 294         bool locked = false;
 295
 296         if (block_group) {
 297                 struct btrfs_path *path = btrfs_alloc_path();
 298
 299                 if (!path) {
 300                         ret = -ENOMEM;
 301                         goto fail;
 302                 }
 303                 locked = true;
 304                 mutex_lock(&trans->transaction->cache_write_mutex);
 305                 if (!list_empty(&block_group->io_list)) {
 306                         list_del_init(&block_group->io_list);
 307
 308                         btrfs_wait_cache_io(trans, block_group, path);
 309                         btrfs_put_block_group(block_group);
 310                 }
 311
 312                 /*
 313                  * now that we've truncated the cache away, its no longer
 314                  * setup or written
 315                  */
 316                 spin_lock(&block_group->lock);
 317                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 318                 spin_unlock(&block_group->lock);
 319                 btrfs_free_path(path);
 320         }
 321
 322         btrfs_i_size_write(BTRFS_I(inode), 0);
 323         truncate_pagecache(inode, 0);
 324
 325         /*
 326          * We skip the throttling logic for free space cache inodes, so we don't
 327          * need to check for -EAGAIN.
 328          */
 329         ret = btrfs_truncate_inode_items(trans, root, BTRFS_I(inode),
 330                                          0, BTRFS_EXTENT_DATA_KEY);
 331         if (ret)
 332                 goto fail;
 333
 334         ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
 335
 336 fail:
 337         if (locked)
 338                 mutex_unlock(&trans->transaction->cache_write_mutex);
 339         if (ret)
 340                 btrfs_abort_transaction(trans, ret);
 341
 342         return ret;
 343 }
 344
 345 static void readahead_cache(struct inode *inode)
 346 {
 347         struct file_ra_state *ra;
 348         unsigned long last_index;
 349
 350         ra = kzalloc(sizeof(*ra), GFP_NOFS);
 351         if (!ra)
 352                 return;
 353
 354         file_ra_state_init(ra, inode->i_mapping);
 355         last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
 356
 357         page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 358
 359         kfree(ra);
 360 }
 361
 362 static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 363                        int write)
 364 {
 365         int num_pages;
 366
 367         num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 368
 369         /* Make sure we can fit our crcs and generation into the first page */
 370         if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
 371                 return -ENOSPC;
 372
 373         memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
 374
 375         io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
 376         if (!io_ctl->pages)
 377                 return -ENOMEM;
 378
 379         io_ctl->num_pages = num_pages;
 380         io_ctl->fs_info = btrfs_sb(inode->i_sb);
 381         io_ctl->inode = inode;
 382
 383         return 0;
 384 }
 385 ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
 386
 387 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
 388 {
 389         kfree(io_ctl->pages);
 390         io_ctl->pages = NULL;
 391 }
 392
 393 static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
 394 {
 395         if (io_ctl->cur) {
 396                 io_ctl->cur = NULL;
 397                 io_ctl->orig = NULL;
 398         }
 399 }
 400
 401 static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
 402 {
 403         ASSERT(io_ctl->index < io_ctl->num_pages);
 404         io_ctl->page = io_ctl->pages[io_ctl->index++];
 405         io_ctl->cur = page_address(io_ctl->page);
 406         io_ctl->orig = io_ctl->cur;
 407         io_ctl->size = PAGE_SIZE;
 408         if (clear)
 409                 clear_page(io_ctl->cur);
 410 }
 411
 412 static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
 413 {
 414         int i;
 415
 416         io_ctl_unmap_page(io_ctl);
 417
 418         for (i = 0; i < io_ctl->num_pages; i++) {
 419                 if (io_ctl->pages[i]) {
 420                         ClearPageChecked(io_ctl->pages[i]);
 421                         unlock_page(io_ctl->pages[i]);
 422                         put_page(io_ctl->pages[i]);
 423                 }
 424         }
 425 }
 426
 427 static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
 428 {
 429         struct page *page;
 430         struct inode *inode = io_ctl->inode;
 431         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 432         int i;
 433
 434         for (i = 0; i < io_ctl->num_pages; i++) {
 435                 int ret;
 436
 437                 page = find_or_create_page(inode->i_mapping, i, mask);
 438                 if (!page) {
 439                         io_ctl_drop_pages(io_ctl);
 440                         return -ENOMEM;
 441                 }
 442
 443                 ret = set_page_extent_mapped(page);
 444                 if (ret < 0) {
 445                         unlock_page(page);
 446                         put_page(page);
 447                         io_ctl_drop_pages(io_ctl);
 448                         return ret;
 449                 }
 450
 451                 io_ctl->pages[i] = page;
 452                 if (uptodate && !PageUptodate(page)) {
 453                         btrfs_readpage(NULL, page);
 454                         lock_page(page);
 455                         if (page->mapping != inode->i_mapping) {
 456                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 457                                           "free space cache page truncated");
 458                                 io_ctl_drop_pages(io_ctl);
 459                                 return -EIO;
 460                         }
 461                         if (!PageUptodate(page)) {
 462                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 463                                            "error reading free space cache");
 464                                 io_ctl_drop_pages(io_ctl);
 465                                 return -EIO;
 466                         }
 467                 }
 468         }
 469
 470         for (i = 0; i < io_ctl->num_pages; i++)
 471                 clear_page_dirty_for_io(io_ctl->pages[i]);
 472
 473         return 0;
 474 }
 475
 476 static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 477 {
 478         io_ctl_map_page(io_ctl, 1);
 479
 480         /*
 481          * Skip the csum areas.  If we don't check crcs then we just have a
 482          * 64bit chunk at the front of the first page.
 483          */
 484         io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 485         io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 486
 487         put_unaligned_le64(generation, io_ctl->cur);
 488         io_ctl->cur += sizeof(u64);
 489 }
 490
 491 static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 492 {
 493         u64 cache_gen;
 494
 495         /*
 496          * Skip the crc area.  If we don't check crcs then we just have a 64bit
 497          * chunk at the front of the first page.
 498          */
 499         io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 500         io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 501
 502         cache_gen = get_unaligned_le64(io_ctl->cur);
 503         if (cache_gen != generation) {
 504                 btrfs_err_rl(io_ctl->fs_info,
 505                         "space cache generation (%llu) does not match inode (%llu)",
 506                                 cache_gen, generation);
 507                 io_ctl_unmap_page(io_ctl);
 508                 return -EIO;
 509         }
 510         io_ctl->cur += sizeof(u64);
 511         return 0;
 512 }
 513
 514 static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
 515 {
 516         u32 *tmp;
 517         u32 crc = ~(u32)0;
 518         unsigned offset = 0;
 519
 520         if (index == 0)
 521                 offset = sizeof(u32) * io_ctl->num_pages;
 522
 523         crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 524         btrfs_crc32c_final(crc, (u8 *)&crc);
 525         io_ctl_unmap_page(io_ctl);
 526         tmp = page_address(io_ctl->pages[0]);
 527         tmp += index;
 528         *tmp = crc;
 529 }
 530
 531 static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
 532 {
 533         u32 *tmp, val;
 534         u32 crc = ~(u32)0;
 535         unsigned offset = 0;
 536
 537         if (index == 0)
 538                 offset = sizeof(u32) * io_ctl->num_pages;
 539
 540         tmp = page_address(io_ctl->pages[0]);
 541         tmp += index;
 542         val = *tmp;
 543
 544         io_ctl_map_page(io_ctl, 0);
 545         crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 546         btrfs_crc32c_final(crc, (u8 *)&crc);
 547         if (val != crc) {
 548                 btrfs_err_rl(io_ctl->fs_info,
 549                         "csum mismatch on free space cache");
 550                 io_ctl_unmap_page(io_ctl);
 551                 return -EIO;
 552         }
 553
 554         return 0;
 555 }
 556
 557 static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
 558                             void *bitmap)
 559 {
 560         struct btrfs_free_space_entry *entry;
 561
 562         if (!io_ctl->cur)
 563                 return -ENOSPC;
 564
 565         entry = io_ctl->cur;
 566         put_unaligned_le64(offset, &entry->offset);
 567         put_unaligned_le64(bytes, &entry->bytes);
 568         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 569                 BTRFS_FREE_SPACE_EXTENT;
 570         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 571         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 572
 573         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 574                 return 0;
 575
 576         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 577
 578         /* No more pages to map */
 579         if (io_ctl->index >= io_ctl->num_pages)
 580                 return 0;
 581
 582         /* map the next page */
 583         io_ctl_map_page(io_ctl, 1);
 584         return 0;
 585 }
 586
 587 static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
 588 {
 589         if (!io_ctl->cur)
 590                 return -ENOSPC;
 591
 592         /*
 593          * If we aren't at the start of the current page, unmap this one and
 594          * map the next one if there is any left.
 595          */
 596         if (io_ctl->cur != io_ctl->orig) {
 597                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 598                 if (io_ctl->index >= io_ctl->num_pages)
 599                         return -ENOSPC;
 600                 io_ctl_map_page(io_ctl, 0);
 601         }
 602
 603         copy_page(io_ctl->cur, bitmap);
 604         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 605         if (io_ctl->index < io_ctl->num_pages)
 606                 io_ctl_map_page(io_ctl, 0);
 607         return 0;
 608 }
 609
 610 static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
 611 {
 612         /*
 613          * If we're not on the boundary we know we've modified the page and we
 614          * need to crc the page.
 615          */
 616         if (io_ctl->cur != io_ctl->orig)
 617                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 618         else
 619                 io_ctl_unmap_page(io_ctl);
 620
 621         while (io_ctl->index < io_ctl->num_pages) {
 622                 io_ctl_map_page(io_ctl, 1);
 623                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 624         }
 625 }
 626
 627 static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
 628                             struct btrfs_free_space *entry, u8 *type)
 629 {
 630         struct btrfs_free_space_entry *e;
 631         int ret;
 632
 633         if (!io_ctl->cur) {
 634                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 635                 if (ret)
 636                         return ret;
 637         }
 638
 639         e = io_ctl->cur;
 640         entry->offset = get_unaligned_le64(&e->offset);
 641         entry->bytes = get_unaligned_le64(&e->bytes);
 642         *type = e->type;
 643         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 644         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 645
 646         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 647                 return 0;
 648
 649         io_ctl_unmap_page(io_ctl);
 650
 651         return 0;
 652 }
 653
 654 static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
 655                               struct btrfs_free_space *entry)
 656 {
 657         int ret;
 658
 659         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 660         if (ret)
 661                 return ret;
 662
 663         copy_page(entry->bitmap, io_ctl->cur);
 664         io_ctl_unmap_page(io_ctl);
 665
 666         return 0;
 667 }
 668
 669 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
 670 {
 671         struct btrfs_block_group *block_group = ctl->private;
 672         u64 max_bytes;
 673         u64 bitmap_bytes;
 674         u64 extent_bytes;
 675         u64 size = block_group->length;
 676         u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
 677         u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
 678
 679         max_bitmaps = max_t(u64, max_bitmaps, 1);
 680
 681         ASSERT(ctl->total_bitmaps <= max_bitmaps);
 682
 683         /*
 684          * We are trying to keep the total amount of memory used per 1GiB of
 685          * space to be MAX_CACHE_BYTES_PER_GIG.  However, with a reclamation
 686          * mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of
 687          * bitmaps, we may end up using more memory than this.
 688          */
 689         if (size < SZ_1G)
 690                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
 691         else
 692                 max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
 693
 694         bitmap_bytes = ctl->total_bitmaps * ctl->unit;
 695
 696         /*
 697          * we want the extent entry threshold to always be at most 1/2 the max
 698          * bytes we can have, or whatever is less than that.
 699          */
 700         extent_bytes = max_bytes - bitmap_bytes;
 701         extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
 702
 703         ctl->extents_thresh =
 704                 div_u64(extent_bytes, sizeof(struct btrfs_free_space));
 705 }
 706
 707 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 708                                    struct btrfs_free_space_ctl *ctl,
 709                                    struct btrfs_path *path, u64 offset)
 710 {
 711         struct btrfs_fs_info *fs_info = root->fs_info;
 712         struct btrfs_free_space_header *header;
 713         struct extent_buffer *leaf;
 714         struct btrfs_io_ctl io_ctl;
 715         struct btrfs_key key;
 716         struct btrfs_free_space *e, *n;
 717         LIST_HEAD(bitmaps);
 718         u64 num_entries;
 719         u64 num_bitmaps;
 720         u64 generation;
 721         u8 type;
 722         int ret = 0;
 723
 724         /* Nothing in the space cache, goodbye */
 725         if (!i_size_read(inode))
 726                 return 0;
 727
 728         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 729         key.offset = offset;
 730         key.type = 0;
 731
 732         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 733         if (ret < 0)
 734                 return 0;
 735         else if (ret > 0) {
 736                 btrfs_release_path(path);
 737                 return 0;
 738         }
 739
 740         ret = -1;
 741
 742         leaf = path->nodes[0];
 743         header = btrfs_item_ptr(leaf, path->slots[0],
 744                                 struct btrfs_free_space_header);
 745         num_entries = btrfs_free_space_entries(leaf, header);
 746         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 747         generation = btrfs_free_space_generation(leaf, header);
 748         btrfs_release_path(path);
 749
 750         if (!BTRFS_I(inode)->generation) {
 751                 btrfs_info(fs_info,
 752                            "the free space cache file (%llu) is invalid, skip it",
 753                            offset);
 754                 return 0;
 755         }
 756
 757         if (BTRFS_I(inode)->generation != generation) {
 758                 btrfs_err(fs_info,
 759                           "free space inode generation (%llu) did not match free space cache generation (%llu)",
 760                           BTRFS_I(inode)->generation, generation);
 761                 return 0;
 762         }
 763
 764         if (!num_entries)
 765                 return 0;
 766
 767         ret = io_ctl_init(&io_ctl, inode, 0);
 768         if (ret)
 769                 return ret;
 770
 771         readahead_cache(inode);
 772
 773         ret = io_ctl_prepare_pages(&io_ctl, true);
 774         if (ret)
 775                 goto out;
 776
 777         ret = io_ctl_check_crc(&io_ctl, 0);
 778         if (ret)
 779                 goto free_cache;
 780
 781         ret = io_ctl_check_generation(&io_ctl, generation);
 782         if (ret)
 783                 goto free_cache;
 784
 785         while (num_entries) {
 786                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
 787                                       GFP_NOFS);
 788                 if (!e) {
 789                         ret = -ENOMEM;
 790                         goto free_cache;
 791                 }
 792
 793                 ret = io_ctl_read_entry(&io_ctl, e, &type);
 794                 if (ret) {
 795                         kmem_cache_free(btrfs_free_space_cachep, e);
 796                         goto free_cache;
 797                 }
 798
 799                 if (!e->bytes) {
 800                         ret = -1;
 801                         kmem_cache_free(btrfs_free_space_cachep, e);
 802                         goto free_cache;
 803                 }
 804
 805                 if (type == BTRFS_FREE_SPACE_EXTENT) {
 806                         spin_lock(&ctl->tree_lock);
 807                         ret = link_free_space(ctl, e);
 808                         spin_unlock(&ctl->tree_lock);
 809                         if (ret) {
 810                                 btrfs_err(fs_info,
 811                                         "Duplicate entries in free space cache, dumping");
 812                                 kmem_cache_free(btrfs_free_space_cachep, e);
 813                                 goto free_cache;
 814                         }
 815                 } else {
 816                         ASSERT(num_bitmaps);
 817                         num_bitmaps--;
 818                         e->bitmap = kmem_cache_zalloc(
 819                                         btrfs_free_space_bitmap_cachep, GFP_NOFS);
 820                         if (!e->bitmap) {
 821                                 ret = -ENOMEM;
 822                                 kmem_cache_free(
 823                                         btrfs_free_space_cachep, e);
 824                                 goto free_cache;
 825                         }
 826                         spin_lock(&ctl->tree_lock);
 827                         ret = link_free_space(ctl, e);
 828                         ctl->total_bitmaps++;
 829                         recalculate_thresholds(ctl);
 830                         spin_unlock(&ctl->tree_lock);
 831                         if (ret) {
 832                                 btrfs_err(fs_info,
 833                                         "Duplicate entries in free space cache, dumping");
 834                                 kmem_cache_free(btrfs_free_space_cachep, e);
 835                                 goto free_cache;
 836                         }
 837                         list_add_tail(&e->list, &bitmaps);
 838                 }
 839
 840                 num_entries--;
 841         }
 842
 843         io_ctl_unmap_page(&io_ctl);
 844
 845         /*
 846          * We add the bitmaps at the end of the entries in order that
 847          * the bitmap entries are added to the cache.
 848          */
 849         list_for_each_entry_safe(e, n, &bitmaps, list) {
 850                 list_del_init(&e->list);
 851                 ret = io_ctl_read_bitmap(&io_ctl, e);
 852                 if (ret)
 853                         goto free_cache;
 854         }
 855
 856         io_ctl_drop_pages(&io_ctl);
 857         ret = 1;
 858 out:
 859         io_ctl_free(&io_ctl);
 860         return ret;
 861 free_cache:
 862         io_ctl_drop_pages(&io_ctl);
 863         __btrfs_remove_free_space_cache(ctl);
 864         goto out;
 865 }
 866
 867 static int copy_free_space_cache(struct btrfs_block_group *block_group,
 868                                  struct btrfs_free_space_ctl *ctl)
 869 {
 870         struct btrfs_free_space *info;
 871         struct rb_node *n;
 872         int ret = 0;
 873
 874         while (!ret && (n = rb_first(&ctl->free_space_offset)) != NULL) {
 875                 info = rb_entry(n, struct btrfs_free_space, offset_index);
 876                 if (!info->bitmap) {
 877                         unlink_free_space(ctl, info);
 878                         ret = btrfs_add_free_space(block_group, info->offset,
 879                                                    info->bytes);
 880                         kmem_cache_free(btrfs_free_space_cachep, info);
 881                 } else {
 882                         u64 offset = info->offset;
 883                         u64 bytes = ctl->unit;
 884
 885                         while (search_bitmap(ctl, info, &offset, &bytes,
 886                                              false) == 0) {
 887                                 ret = btrfs_add_free_space(block_group, offset,
 888                                                            bytes);
 889                                 if (ret)
 890                                         break;
 891                                 bitmap_clear_bits(ctl, info, offset, bytes);
 892                                 offset = info->offset;
 893                                 bytes = ctl->unit;
 894                         }
 895                         free_bitmap(ctl, info);
 896                 }
 897                 cond_resched();
 898         }
 899         return ret;
 900 }
 901
 902 int load_free_space_cache(struct btrfs_block_group *block_group)
 903 {
 904         struct btrfs_fs_info *fs_info = block_group->fs_info;
 905         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 906         struct btrfs_free_space_ctl tmp_ctl = {};
 907         struct inode *inode;
 908         struct btrfs_path *path;
 909         int ret = 0;
 910         bool matched;
 911         u64 used = block_group->used;
 912
 913         /*
 914          * Because we could potentially discard our loaded free space, we want
 915          * to load everything into a temporary structure first, and then if it's
 916          * valid copy it all into the actual free space ctl.
 917          */
 918         btrfs_init_free_space_ctl(block_group, &tmp_ctl);
 919
 920         /*
 921          * If this block group has been marked to be cleared for one reason or
 922          * another then we can't trust the on disk cache, so just return.
 923          */
 924         spin_lock(&block_group->lock);
 925         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 926                 spin_unlock(&block_group->lock);
 927                 return 0;
 928         }
 929         spin_unlock(&block_group->lock);
 930
 931         path = btrfs_alloc_path();
 932         if (!path)
 933                 return 0;
 934         path->search_commit_root = 1;
 935         path->skip_locking = 1;
 936
 937         /*
 938          * We must pass a path with search_commit_root set to btrfs_iget in
 939          * order to avoid a deadlock when allocating extents for the tree root.
 940          *
 941          * When we are COWing an extent buffer from the tree root, when looking
 942          * for a free extent, at extent-tree.c:find_free_extent(), we can find
 943          * block group without its free space cache loaded. When we find one
 944          * we must load its space cache which requires reading its free space
 945          * cache's inode item from the root tree. If this inode item is located
 946          * in the same leaf that we started COWing before, then we end up in
 947          * deadlock on the extent buffer (trying to read lock it when we
 948          * previously write locked it).
 949          *
 950          * It's safe to read the inode item using the commit root because
 951          * block groups, once loaded, stay in memory forever (until they are
 952          * removed) as well as their space caches once loaded. New block groups
 953          * once created get their ->cached field set to BTRFS_CACHE_FINISHED so
 954          * we will never try to read their inode item while the fs is mounted.
 955          */
 956         inode = lookup_free_space_inode(block_group, path);
 957         if (IS_ERR(inode)) {
 958                 btrfs_free_path(path);
 959                 return 0;
 960         }
 961
 962         /* We may have converted the inode and made the cache invalid. */
 963         spin_lock(&block_group->lock);
 964         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 965                 spin_unlock(&block_group->lock);
 966                 btrfs_free_path(path);
 967                 goto out;
 968         }
 969         spin_unlock(&block_group->lock);
 970
 971         ret = __load_free_space_cache(fs_info->tree_root, inode, &tmp_ctl,
 972                                       path, block_group->start);
 973         btrfs_free_path(path);
 974         if (ret <= 0)
 975                 goto out;
 976
 977         matched = (tmp_ctl.free_space == (block_group->length - used -
 978                                           block_group->bytes_super));
 979
 980         if (matched) {
 981                 ret = copy_free_space_cache(block_group, &tmp_ctl);
 982                 /*
 983                  * ret == 1 means we successfully loaded the free space cache,
 984                  * so we need to re-set it here.
 985                  */
 986                 if (ret == 0)
 987                         ret = 1;
 988         } else {
 989                 __btrfs_remove_free_space_cache(&tmp_ctl);
 990                 btrfs_warn(fs_info,
 991                            "block group %llu has wrong amount of free space",
 992                            block_group->start);
 993                 ret = -1;
 994         }
 995 out:
 996         if (ret < 0) {
 997                 /* This cache is bogus, make sure it gets cleared */
 998                 spin_lock(&block_group->lock);
 999                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
1000                 spin_unlock(&block_group->lock);
1001                 ret = 0;
1002
1003                 btrfs_warn(fs_info,
1004                            "failed to load free space cache for block group %llu, rebuilding it now",
1005                            block_group->start);
1006         }
1007
1008         spin_lock(&ctl->tree_lock);
1009         btrfs_discard_update_discardable(block_group);
1010         spin_unlock(&ctl->tree_lock);
1011         iput(inode);
1012         return ret;
1013 }
1014
1015 static noinline_for_stack
1016 int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
1017                               struct btrfs_free_space_ctl *ctl,
1018                               struct btrfs_block_group *block_group,
1019                               int *entries, int *bitmaps,
1020                               struct list_head *bitmap_list)
1021 {
1022         int ret;
1023         struct btrfs_free_cluster *cluster = NULL;
1024         struct btrfs_free_cluster *cluster_locked = NULL;
1025         struct rb_node *node = rb_first(&ctl->free_space_offset);
1026         struct btrfs_trim_range *trim_entry;
1027
1028         /* Get the cluster for this block_group if it exists */
1029         if (block_group && !list_empty(&block_group->cluster_list)) {
1030                 cluster = list_entry(block_group->cluster_list.next,
1031                                      struct btrfs_free_cluster,
1032                                      block_group_list);
1033         }
1034
1035         if (!node && cluster) {
1036                 cluster_locked = cluster;
1037                 spin_lock(&cluster_locked->lock);
1038                 node = rb_first(&cluster->root);
1039                 cluster = NULL;
1040         }
1041
1042         /* Write out the extent entries */
1043         while (node) {
1044                 struct btrfs_free_space *e;
1045
1046                 e = rb_entry(node, struct btrfs_free_space, offset_index);
1047                 *entries += 1;
1048
1049                 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
1050                                        e->bitmap);
1051                 if (ret)
1052                         goto fail;
1053
1054                 if (e->bitmap) {
1055                         list_add_tail(&e->list, bitmap_list);
1056                         *bitmaps += 1;
1057                 }
1058                 node = rb_next(node);
1059                 if (!node && cluster) {
1060                         node = rb_first(&cluster->root);
1061                         cluster_locked = cluster;
1062                         spin_lock(&cluster_locked->lock);
1063                         cluster = NULL;
1064                 }
1065         }
1066         if (cluster_locked) {
1067                 spin_unlock(&cluster_locked->lock);
1068                 cluster_locked = NULL;
1069         }
1070
1071         /*
1072          * Make sure we don't miss any range that was removed from our rbtree
1073          * because trimming is running. Otherwise after a umount+mount (or crash
1074          * after committing the transaction) we would leak free space and get
1075          * an inconsistent free space cache report from fsck.
1076          */
1077         list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
1078                 ret = io_ctl_add_entry(io_ctl, trim_entry->start,
1079                                        trim_entry->bytes, NULL);
1080                 if (ret)
1081                         goto fail;
1082                 *entries += 1;
1083         }
1084
1085         return 0;
1086 fail:
1087         if (cluster_locked)
1088                 spin_unlock(&cluster_locked->lock);
1089         return -ENOSPC;
1090 }
1091
1092 static noinline_for_stack int
1093 update_cache_item(struct btrfs_trans_handle *trans,
1094                   struct btrfs_root *root,
1095                   struct inode *inode,
1096                   struct btrfs_path *path, u64 offset,
1097                   int entries, int bitmaps)
1098 {
1099         struct btrfs_key key;
1100         struct btrfs_free_space_header *header;
1101         struct extent_buffer *leaf;
1102         int ret;
1103
1104         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1105         key.offset = offset;
1106         key.type = 0;
1107
1108         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1109         if (ret < 0) {
1110                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1111                                  EXTENT_DELALLOC, 0, 0, NULL);
1112                 goto fail;
1113         }
1114         leaf = path->nodes[0];
1115         if (ret > 0) {
1116                 struct btrfs_key found_key;
1117                 ASSERT(path->slots[0]);
1118                 path->slots[0]--;
1119                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1120                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1121                     found_key.offset != offset) {
1122                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1123                                          inode->i_size - 1, EXTENT_DELALLOC, 0,
1124                                          0, NULL);
1125                         btrfs_release_path(path);
1126                         goto fail;
1127                 }
1128         }
1129
1130         BTRFS_I(inode)->generation = trans->transid;
1131         header = btrfs_item_ptr(leaf, path->slots[0],
1132                                 struct btrfs_free_space_header);
1133         btrfs_set_free_space_entries(leaf, header, entries);
1134         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1135         btrfs_set_free_space_generation(leaf, header, trans->transid);
1136         btrfs_mark_buffer_dirty(leaf);
1137         btrfs_release_path(path);
1138
1139         return 0;
1140
1141 fail:
1142         return -1;
1143 }
1144
1145 static noinline_for_stack int write_pinned_extent_entries(
1146                             struct btrfs_trans_handle *trans,
1147                             struct btrfs_block_group *block_group,
1148                             struct btrfs_io_ctl *io_ctl,
1149                             int *entries)
1150 {
1151         u64 start, extent_start, extent_end, len;
1152         struct extent_io_tree *unpin = NULL;
1153         int ret;
1154
1155         if (!block_group)
1156                 return 0;
1157
1158         /*
1159          * We want to add any pinned extents to our free space cache
1160          * so we don't leak the space
1161          *
1162          * We shouldn't have switched the pinned extents yet so this is the
1163          * right one
1164          */
1165         unpin = &trans->transaction->pinned_extents;
1166
1167         start = block_group->start;
1168
1169         while (start < block_group->start + block_group->length) {
1170                 ret = find_first_extent_bit(unpin, start,
1171                                             &extent_start, &extent_end,
1172                                             EXTENT_DIRTY, NULL);
1173                 if (ret)
1174                         return 0;
1175
1176                 /* This pinned extent is out of our range */
1177                 if (extent_start >= block_group->start + block_group->length)
1178                         return 0;
1179
1180                 extent_start = max(extent_start, start);
1181                 extent_end = min(block_group->start + block_group->length,
1182                                  extent_end + 1);
1183                 len = extent_end - extent_start;
1184
1185                 *entries += 1;
1186                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1187                 if (ret)
1188                         return -ENOSPC;
1189
1190                 start = extent_end;
1191         }
1192
1193         return 0;
1194 }
1195
1196 static noinline_for_stack int
1197 write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1198 {
1199         struct btrfs_free_space *entry, *next;
1200         int ret;
1201
1202         /* Write out the bitmaps */
1203         list_for_each_entry_safe(entry, next, bitmap_list, list) {
1204                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1205                 if (ret)
1206                         return -ENOSPC;
1207                 list_del_init(&entry->list);
1208         }
1209
1210         return 0;
1211 }
1212
1213 static int flush_dirty_cache(struct inode *inode)
1214 {
1215         int ret;
1216
1217         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1218         if (ret)
1219                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1220                                  EXTENT_DELALLOC, 0, 0, NULL);
1221
1222         return ret;
1223 }
1224
1225 static void noinline_for_stack
1226 cleanup_bitmap_list(struct list_head *bitmap_list)
1227 {
1228         struct btrfs_free_space *entry, *next;
1229
1230         list_for_each_entry_safe(entry, next, bitmap_list, list)
1231                 list_del_init(&entry->list);
1232 }
1233
1234 static void noinline_for_stack
1235 cleanup_write_cache_enospc(struct inode *inode,
1236                            struct btrfs_io_ctl *io_ctl,
1237                            struct extent_state **cached_state)
1238 {
1239         io_ctl_drop_pages(io_ctl);
1240         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1241                              i_size_read(inode) - 1, cached_state);
1242 }
1243
1244 static int __btrfs_wait_cache_io(struct btrfs_root *root,
1245                                  struct btrfs_trans_handle *trans,
1246                                  struct btrfs_block_group *block_group,
1247                                  struct btrfs_io_ctl *io_ctl,
1248                                  struct btrfs_path *path, u64 offset)
1249 {
1250         int ret;
1251         struct inode *inode = io_ctl->inode;
1252
1253         if (!inode)
1254                 return 0;
1255
1256         /* Flush the dirty pages in the cache file. */
1257         ret = flush_dirty_cache(inode);
1258         if (ret)
1259                 goto out;
1260
1261         /* Update the cache item to tell everyone this cache file is valid. */
1262         ret = update_cache_item(trans, root, inode, path, offset,
1263                                 io_ctl->entries, io_ctl->bitmaps);
1264 out:
1265         if (ret) {
1266                 invalidate_inode_pages2(inode->i_mapping);
1267                 BTRFS_I(inode)->generation = 0;
1268                 if (block_group)
1269                         btrfs_debug(root->fs_info,
1270           "failed to write free space cache for block group %llu error %d",
1271                                   block_group->start, ret);
1272         }
1273         btrfs_update_inode(trans, root, BTRFS_I(inode));
1274
1275         if (block_group) {
1276                 /* the dirty list is protected by the dirty_bgs_lock */
1277                 spin_lock(&trans->transaction->dirty_bgs_lock);
1278
1279                 /* the disk_cache_state is protected by the block group lock */
1280                 spin_lock(&block_group->lock);
1281
1282                 /*
1283                  * only mark this as written if we didn't get put back on
1284                  * the dirty list while waiting for IO.   Otherwise our
1285                  * cache state won't be right, and we won't get written again
1286                  */
1287                 if (!ret && list_empty(&block_group->dirty_list))
1288                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1289                 else if (ret)
1290                         block_group->disk_cache_state = BTRFS_DC_ERROR;
1291
1292                 spin_unlock(&block_group->lock);
1293                 spin_unlock(&trans->transaction->dirty_bgs_lock);
1294                 io_ctl->inode = NULL;
1295                 iput(inode);
1296         }
1297
1298         return ret;
1299
1300 }
1301
1302 int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
1303                         struct btrfs_block_group *block_group,
1304                         struct btrfs_path *path)
1305 {
1306         return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
1307                                      block_group, &block_group->io_ctl,
1308                                      path, block_group->start);
1309 }
1310
1311 /**
1312  * Write out cached info to an inode
1313  *
1314  * @root:        root the inode belongs to
1315  * @inode:       freespace inode we are writing out
1316  * @ctl:         free space cache we are going to write out
1317  * @block_group: block_group for this cache if it belongs to a block_group
1318  * @io_ctl:      holds context for the io
1319  * @trans:       the trans handle
1320  *
1321  * This function writes out a free space cache struct to disk for quick recovery
1322  * on mount.  This will return 0 if it was successful in writing the cache out,
1323  * or an errno if it was not.
1324  */
1325 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1326                                    struct btrfs_free_space_ctl *ctl,
1327                                    struct btrfs_block_group *block_group,
1328                                    struct btrfs_io_ctl *io_ctl,
1329                                    struct btrfs_trans_handle *trans)
1330 {
1331         struct extent_state *cached_state = NULL;
1332         LIST_HEAD(bitmap_list);
1333         int entries = 0;
1334         int bitmaps = 0;
1335         int ret;
1336         int must_iput = 0;
1337
1338         if (!i_size_read(inode))
1339                 return -EIO;
1340
1341         WARN_ON(io_ctl->pages);
1342         ret = io_ctl_init(io_ctl, inode, 1);
1343         if (ret)
1344                 return ret;
1345
1346         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1347                 down_write(&block_group->data_rwsem);
1348                 spin_lock(&block_group->lock);
1349                 if (block_group->delalloc_bytes) {
1350                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1351                         spin_unlock(&block_group->lock);
1352                         up_write(&block_group->data_rwsem);
1353                         BTRFS_I(inode)->generation = 0;
1354                         ret = 0;
1355                         must_iput = 1;
1356                         goto out;
1357                 }
1358                 spin_unlock(&block_group->lock);
1359         }
1360
1361         /* Lock all pages first so we can lock the extent safely. */
1362         ret = io_ctl_prepare_pages(io_ctl, false);
1363         if (ret)
1364                 goto out_unlock;
1365
1366         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1367                          &cached_state);
1368
1369         io_ctl_set_generation(io_ctl, trans->transid);
1370
1371         mutex_lock(&ctl->cache_writeout_mutex);
1372         /* Write out the extent entries in the free space cache */
1373         spin_lock(&ctl->tree_lock);
1374         ret = write_cache_extent_entries(io_ctl, ctl,
1375                                          block_group, &entries, &bitmaps,
1376                                          &bitmap_list);
1377         if (ret)
1378                 goto out_nospc_locked;
1379
1380         /*
1381          * Some spaces that are freed in the current transaction are pinned,
1382          * they will be added into free space cache after the transaction is
1383          * committed, we shouldn't lose them.
1384          *
1385          * If this changes while we are working we'll get added back to
1386          * the dirty list and redo it.  No locking needed
1387          */
1388         ret = write_pinned_extent_entries(trans, block_group, io_ctl, &entries);
1389         if (ret)
1390                 goto out_nospc_locked;
1391
1392         /*
1393          * At last, we write out all the bitmaps and keep cache_writeout_mutex
1394          * locked while doing it because a concurrent trim can be manipulating
1395          * or freeing the bitmap.
1396          */
1397         ret = write_bitmap_entries(io_ctl, &bitmap_list);
1398         spin_unlock(&ctl->tree_lock);
1399         mutex_unlock(&ctl->cache_writeout_mutex);
1400         if (ret)
1401                 goto out_nospc;
1402
1403         /* Zero out the rest of the pages just to make sure */
1404         io_ctl_zero_remaining_pages(io_ctl);
1405
1406         /* Everything is written out, now we dirty the pages in the file. */
1407         ret = btrfs_dirty_pages(BTRFS_I(inode), io_ctl->pages,
1408                                 io_ctl->num_pages, 0, i_size_read(inode),
1409                                 &cached_state, false);
1410         if (ret)
1411                 goto out_nospc;
1412
1413         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1414                 up_write(&block_group->data_rwsem);
1415         /*
1416          * Release the pages and unlock the extent, we will flush
1417          * them out later
1418          */
1419         io_ctl_drop_pages(io_ctl);
1420         io_ctl_free(io_ctl);
1421
1422         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1423                              i_size_read(inode) - 1, &cached_state);
1424
1425         /*
1426          * at this point the pages are under IO and we're happy,
1427          * The caller is responsible for waiting on them and updating
1428          * the cache and the inode
1429          */
1430         io_ctl->entries = entries;
1431         io_ctl->bitmaps = bitmaps;
1432
1433         ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
1434         if (ret)
1435                 goto out;
1436
1437         return 0;
1438
1439 out_nospc_locked:
1440         cleanup_bitmap_list(&bitmap_list);
1441         spin_unlock(&ctl->tree_lock);
1442         mutex_unlock(&ctl->cache_writeout_mutex);
1443
1444 out_nospc:
1445         cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
1446
1447 out_unlock:
1448         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1449                 up_write(&block_group->data_rwsem);
1450
1451 out:
1452         io_ctl->inode = NULL;
1453         io_ctl_free(io_ctl);
1454         if (ret) {
1455                 invalidate_inode_pages2(inode->i_mapping);
1456                 BTRFS_I(inode)->generation = 0;
1457         }
1458         btrfs_update_inode(trans, root, BTRFS_I(inode));
1459         if (must_iput)
1460                 iput(inode);
1461         return ret;
1462 }
1463
1464 int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
1465                           struct btrfs_block_group *block_group,
1466                           struct btrfs_path *path)
1467 {
1468         struct btrfs_fs_info *fs_info = trans->fs_info;
1469         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1470         struct inode *inode;
1471         int ret = 0;
1472
1473         spin_lock(&block_group->lock);
1474         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1475                 spin_unlock(&block_group->lock);
1476                 return 0;
1477         }
1478         spin_unlock(&block_group->lock);
1479
1480         inode = lookup_free_space_inode(block_group, path);
1481         if (IS_ERR(inode))
1482                 return 0;
1483
1484         ret = __btrfs_write_out_cache(fs_info->tree_root, inode, ctl,
1485                                 block_group, &block_group->io_ctl, trans);
1486         if (ret) {
1487                 btrfs_debug(fs_info,
1488           "failed to write free space cache for block group %llu error %d",
1489                           block_group->start, ret);
1490                 spin_lock(&block_group->lock);
1491                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1492                 spin_unlock(&block_group->lock);
1493
1494                 block_group->io_ctl.inode = NULL;
1495                 iput(inode);
1496         }
1497
1498         /*
1499          * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1500          * to wait for IO and put the inode
1501          */
1502
1503         return ret;
1504 }
1505
1506 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1507                                           u64 offset)
1508 {
1509         ASSERT(offset >= bitmap_start);
1510         offset -= bitmap_start;
1511         return (unsigned long)(div_u64(offset, unit));
1512 }
1513
1514 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1515 {
1516         return (unsigned long)(div_u64(bytes, unit));
1517 }
1518
1519 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1520                                    u64 offset)
1521 {
1522         u64 bitmap_start;
1523         u64 bytes_per_bitmap;
1524
1525         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1526         bitmap_start = offset - ctl->start;
1527         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1528         bitmap_start *= bytes_per_bitmap;
1529         bitmap_start += ctl->start;
1530
1531         return bitmap_start;
1532 }
1533
1534 static int tree_insert_offset(struct rb_root *root, u64 offset,
1535                               struct rb_node *node, int bitmap)
1536 {
1537         struct rb_node **p = &root->rb_node;
1538         struct rb_node *parent = NULL;
1539         struct btrfs_free_space *info;
1540
1541         while (*p) {
1542                 parent = *p;
1543                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1544
1545                 if (offset < info->offset) {
1546                         p = &(*p)->rb_left;
1547                 } else if (offset > info->offset) {
1548                         p = &(*p)->rb_right;
1549                 } else {
1550                         /*
1551                          * we could have a bitmap entry and an extent entry
1552                          * share the same offset.  If this is the case, we want
1553                          * the extent entry to always be found first if we do a
1554                          * linear search through the tree, since we want to have
1555                          * the quickest allocation time, and allocating from an
1556                          * extent is faster than allocating from a bitmap.  So
1557                          * if we're inserting a bitmap and we find an entry at
1558                          * this offset, we want to go right, or after this entry
1559                          * logically.  If we are inserting an extent and we've
1560                          * found a bitmap, we want to go left, or before
1561                          * logically.
1562                          */
1563                         if (bitmap) {
1564                                 if (info->bitmap) {
1565                                         WARN_ON_ONCE(1);
1566                                         return -EEXIST;
1567                                 }
1568                                 p = &(*p)->rb_right;
1569                         } else {
1570                                 if (!info->bitmap) {
1571                                         WARN_ON_ONCE(1);
1572                                         return -EEXIST;
1573                                 }
1574                                 p = &(*p)->rb_left;
1575                         }
1576                 }
1577         }
1578
1579         rb_link_node(node, parent, p);
1580         rb_insert_color(node, root);
1581
1582         return 0;
1583 }
1584
1585 /*
1586  * searches the tree for the given offset.
1587  *
1588  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1589  * want a section that has at least bytes size and comes at or after the given
1590  * offset.
1591  */
1592 static struct btrfs_free_space *
1593 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1594                    u64 offset, int bitmap_only, int fuzzy)
1595 {
1596         struct rb_node *n = ctl->free_space_offset.rb_node;
1597         struct btrfs_free_space *entry, *prev = NULL;
1598
1599         /* find entry that is closest to the 'offset' */
1600         while (1) {
1601                 if (!n) {
1602                         entry = NULL;
1603                         break;
1604                 }
1605
1606                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1607                 prev = entry;
1608
1609                 if (offset < entry->offset)
1610                         n = n->rb_left;
1611                 else if (offset > entry->offset)
1612                         n = n->rb_right;
1613                 else
1614                         break;
1615         }
1616
1617         if (bitmap_only) {
1618                 if (!entry)
1619                         return NULL;
1620                 if (entry->bitmap)
1621                         return entry;
1622
1623                 /*
1624                  * bitmap entry and extent entry may share same offset,
1625                  * in that case, bitmap entry comes after extent entry.
1626                  */
1627                 n = rb_next(n);
1628                 if (!n)
1629                         return NULL;
1630                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1631                 if (entry->offset != offset)
1632                         return NULL;
1633
1634                 WARN_ON(!entry->bitmap);
1635                 return entry;
1636         } else if (entry) {
1637                 if (entry->bitmap) {
1638                         /*
1639                          * if previous extent entry covers the offset,
1640                          * we should return it instead of the bitmap entry
1641                          */
1642                         n = rb_prev(&entry->offset_index);
1643                         if (n) {
1644                                 prev = rb_entry(n, struct btrfs_free_space,
1645                                                 offset_index);
1646                                 if (!prev->bitmap &&
1647                                     prev->offset + prev->bytes > offset)
1648                                         entry = prev;
1649                         }
1650                 }
1651                 return entry;
1652         }
1653
1654         if (!prev)
1655                 return NULL;
1656
1657         /* find last entry before the 'offset' */
1658         entry = prev;
1659         if (entry->offset > offset) {
1660                 n = rb_prev(&entry->offset_index);
1661                 if (n) {
1662                         entry = rb_entry(n, struct btrfs_free_space,
1663                                         offset_index);
1664                         ASSERT(entry->offset <= offset);
1665                 } else {
1666                         if (fuzzy)
1667                                 return entry;
1668                         else
1669                                 return NULL;
1670                 }
1671         }
1672
1673         if (entry->bitmap) {
1674                 n = rb_prev(&entry->offset_index);
1675                 if (n) {
1676                         prev = rb_entry(n, struct btrfs_free_space,
1677                                         offset_index);
1678                         if (!prev->bitmap &&
1679                             prev->offset + prev->bytes > offset)
1680                                 return prev;
1681                 }
1682                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1683                         return entry;
1684         } else if (entry->offset + entry->bytes > offset)
1685                 return entry;
1686
1687         if (!fuzzy)
1688                 return NULL;
1689
1690         while (1) {
1691                 if (entry->bitmap) {
1692                         if (entry->offset + BITS_PER_BITMAP *
1693                             ctl->unit > offset)
1694                                 break;
1695                 } else {
1696                         if (entry->offset + entry->bytes > offset)
1697                                 break;
1698                 }
1699
1700                 n = rb_next(&entry->offset_index);
1701                 if (!n)
1702                         return NULL;
1703                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1704         }
1705         return entry;
1706 }
1707
1708 static inline void
1709 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1710                     struct btrfs_free_space *info)
1711 {
1712         rb_erase(&info->offset_index, &ctl->free_space_offset);
1713         ctl->free_extents--;
1714
1715         if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1716                 ctl->discardable_extents[BTRFS_STAT_CURR]--;
1717                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
1718         }
1719 }
1720
1721 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1722                               struct btrfs_free_space *info)
1723 {
1724         __unlink_free_space(ctl, info);
1725         ctl->free_space -= info->bytes;
1726 }
1727
1728 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1729                            struct btrfs_free_space *info)
1730 {
1731         int ret = 0;
1732
1733         ASSERT(info->bytes || info->bitmap);
1734         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1735                                  &info->offset_index, (info->bitmap != NULL));
1736         if (ret)
1737                 return ret;
1738
1739         if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1740                 ctl->discardable_extents[BTRFS_STAT_CURR]++;
1741                 ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
1742         }
1743
1744         ctl->free_space += info->bytes;
1745         ctl->free_extents++;
1746         return ret;
1747 }
1748
1749 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1750                                        struct btrfs_free_space *info,
1751                                        u64 offset, u64 bytes)
1752 {
1753         unsigned long start, count, end;
1754         int extent_delta = -1;
1755
1756         start = offset_to_bit(info->offset, ctl->unit, offset);
1757         count = bytes_to_bits(bytes, ctl->unit);
1758         end = start + count;
1759         ASSERT(end <= BITS_PER_BITMAP);
1760
1761         bitmap_clear(info->bitmap, start, count);
1762
1763         info->bytes -= bytes;
1764         if (info->max_extent_size > ctl->unit)
1765                 info->max_extent_size = 0;
1766
1767         if (start && test_bit(start - 1, info->bitmap))
1768                 extent_delta++;
1769
1770         if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1771                 extent_delta++;
1772
1773         info->bitmap_extents += extent_delta;
1774         if (!btrfs_free_space_trimmed(info)) {
1775                 ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1776                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
1777         }
1778 }
1779
1780 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1781                               struct btrfs_free_space *info, u64 offset,
1782                               u64 bytes)
1783 {
1784         __bitmap_clear_bits(ctl, info, offset, bytes);
1785         ctl->free_space -= bytes;
1786 }
1787
1788 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1789                             struct btrfs_free_space *info, u64 offset,
1790                             u64 bytes)
1791 {
1792         unsigned long start, count, end;
1793         int extent_delta = 1;
1794
1795         start = offset_to_bit(info->offset, ctl->unit, offset);
1796         count = bytes_to_bits(bytes, ctl->unit);
1797         end = start + count;
1798         ASSERT(end <= BITS_PER_BITMAP);
1799
1800         bitmap_set(info->bitmap, start, count);
1801
1802         info->bytes += bytes;
1803         ctl->free_space += bytes;
1804
1805         if (start && test_bit(start - 1, info->bitmap))
1806                 extent_delta--;
1807
1808         if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1809                 extent_delta--;
1810
1811         info->bitmap_extents += extent_delta;
1812         if (!btrfs_free_space_trimmed(info)) {
1813                 ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1814                 ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
1815         }
1816 }
1817
1818 /*
1819  * If we can not find suitable extent, we will use bytes to record
1820  * the size of the max extent.
1821  */
1822 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1823                          struct btrfs_free_space *bitmap_info, u64 *offset,
1824                          u64 *bytes, bool for_alloc)
1825 {
1826         unsigned long found_bits = 0;
1827         unsigned long max_bits = 0;
1828         unsigned long bits, i;
1829         unsigned long next_zero;
1830         unsigned long extent_bits;
1831
1832         /*
1833          * Skip searching the bitmap if we don't have a contiguous section that
1834          * is large enough for this allocation.
1835          */
1836         if (for_alloc &&
1837             bitmap_info->max_extent_size &&
1838             bitmap_info->max_extent_size < *bytes) {
1839                 *bytes = bitmap_info->max_extent_size;
1840                 return -1;
1841         }
1842
1843         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1844                           max_t(u64, *offset, bitmap_info->offset));
1845         bits = bytes_to_bits(*bytes, ctl->unit);
1846
1847         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1848                 if (for_alloc && bits == 1) {
1849                         found_bits = 1;
1850                         break;
1851                 }
1852                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1853                                                BITS_PER_BITMAP, i);
1854                 extent_bits = next_zero - i;
1855                 if (extent_bits >= bits) {
1856                         found_bits = extent_bits;
1857                         break;
1858                 } else if (extent_bits > max_bits) {
1859                         max_bits = extent_bits;
1860                 }
1861                 i = next_zero;
1862         }
1863
1864         if (found_bits) {
1865                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1866                 *bytes = (u64)(found_bits) * ctl->unit;
1867                 return 0;
1868         }
1869
1870         *bytes = (u64)(max_bits) * ctl->unit;
1871         bitmap_info->max_extent_size = *bytes;
1872         return -1;
1873 }
1874
1875 static inline u64 get_max_extent_size(struct btrfs_free_space *entry)
1876 {
1877         if (entry->bitmap)
1878                 return entry->max_extent_size;
1879         return entry->bytes;
1880 }
1881
1882 /* Cache the size of the max extent in bytes */
1883 static struct btrfs_free_space *
1884 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1885                 unsigned long align, u64 *max_extent_size)
1886 {
1887         struct btrfs_free_space *entry;
1888         struct rb_node *node;
1889         u64 tmp;
1890         u64 align_off;
1891         int ret;
1892
1893         if (!ctl->free_space_offset.rb_node)
1894                 goto out;
1895
1896         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1897         if (!entry)
1898                 goto out;
1899
1900         for (node = &entry->offset_index; node; node = rb_next(node)) {
1901                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1902                 if (entry->bytes < *bytes) {
1903                         *max_extent_size = max(get_max_extent_size(entry),
1904                                                *max_extent_size);
1905                         continue;
1906                 }
1907
1908                 /* make sure the space returned is big enough
1909                  * to match our requested alignment
1910                  */
1911                 if (*bytes >= align) {
1912                         tmp = entry->offset - ctl->start + align - 1;
1913                         tmp = div64_u64(tmp, align);
1914                         tmp = tmp * align + ctl->start;
1915                         align_off = tmp - entry->offset;
1916                 } else {
1917                         align_off = 0;
1918                         tmp = entry->offset;
1919                 }
1920
1921                 if (entry->bytes < *bytes + align_off) {
1922                         *max_extent_size = max(get_max_extent_size(entry),
1923                                                *max_extent_size);
1924                         continue;
1925                 }
1926
1927                 if (entry->bitmap) {
1928                         u64 size = *bytes;
1929
1930                         ret = search_bitmap(ctl, entry, &tmp, &size, true);
1931                         if (!ret) {
1932                                 *offset = tmp;
1933                                 *bytes = size;
1934                                 return entry;
1935                         } else {
1936                                 *max_extent_size =
1937                                         max(get_max_extent_size(entry),
1938                                             *max_extent_size);
1939                         }
1940                         continue;
1941                 }
1942
1943                 *offset = tmp;
1944                 *bytes = entry->bytes - align_off;
1945                 return entry;
1946         }
1947 out:
1948         return NULL;
1949 }
1950
1951 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1952                            struct btrfs_free_space *info, u64 offset)
1953 {
1954         info->offset = offset_to_bitmap(ctl, offset);
1955         info->bytes = 0;
1956         info->bitmap_extents = 0;
1957         INIT_LIST_HEAD(&info->list);
1958         link_free_space(ctl, info);
1959         ctl->total_bitmaps++;
1960         recalculate_thresholds(ctl);
1961 }
1962
1963 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1964                         struct btrfs_free_space *bitmap_info)
1965 {
1966         /*
1967          * Normally when this is called, the bitmap is completely empty. However,
1968          * if we are blowing up the free space cache for one reason or another
1969          * via __btrfs_remove_free_space_cache(), then it may not be freed and
1970          * we may leave stats on the table.
1971          */
1972         if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) {
1973                 ctl->discardable_extents[BTRFS_STAT_CURR] -=
1974                         bitmap_info->bitmap_extents;
1975                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
1976
1977         }
1978         unlink_free_space(ctl, bitmap_info);
1979         kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
1980         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1981         ctl->total_bitmaps--;
1982         recalculate_thresholds(ctl);
1983 }
1984
1985 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1986                               struct btrfs_free_space *bitmap_info,
1987                               u64 *offset, u64 *bytes)
1988 {
1989         u64 end;
1990         u64 search_start, search_bytes;
1991         int ret;
1992
1993 again:
1994         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1995
1996         /*
1997          * We need to search for bits in this bitmap.  We could only cover some
1998          * of the extent in this bitmap thanks to how we add space, so we need
1999          * to search for as much as it as we can and clear that amount, and then
2000          * go searching for the next bit.
2001          */
2002         search_start = *offset;
2003         search_bytes = ctl->unit;
2004         search_bytes = min(search_bytes, end - search_start + 1);
2005         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
2006                             false);
2007         if (ret < 0 || search_start != *offset)
2008                 return -EINVAL;
2009
2010         /* We may have found more bits than what we need */
2011         search_bytes = min(search_bytes, *bytes);
2012
2013         /* Cannot clear past the end of the bitmap */
2014         search_bytes = min(search_bytes, end - search_start + 1);
2015
2016         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
2017         *offset += search_bytes;
2018         *bytes -= search_bytes;
2019
2020         if (*bytes) {
2021                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
2022                 if (!bitmap_info->bytes)
2023                         free_bitmap(ctl, bitmap_info);
2024
2025                 /*
2026                  * no entry after this bitmap, but we still have bytes to
2027                  * remove, so something has gone wrong.
2028                  */
2029                 if (!next)
2030                         return -EINVAL;
2031
2032                 bitmap_info = rb_entry(next, struct btrfs_free_space,
2033                                        offset_index);
2034
2035                 /*
2036                  * if the next entry isn't a bitmap we need to return to let the
2037                  * extent stuff do its work.
2038                  */
2039                 if (!bitmap_info->bitmap)
2040                         return -EAGAIN;
2041
2042                 /*
2043                  * Ok the next item is a bitmap, but it may not actually hold
2044                  * the information for the rest of this free space stuff, so
2045                  * look for it, and if we don't find it return so we can try
2046                  * everything over again.
2047                  */
2048                 search_start = *offset;
2049                 search_bytes = ctl->unit;
2050                 ret = search_bitmap(ctl, bitmap_info, &search_start,
2051                                     &search_bytes, false);
2052                 if (ret < 0 || search_start != *offset)
2053                         return -EAGAIN;
2054
2055                 goto again;
2056         } else if (!bitmap_info->bytes)
2057                 free_bitmap(ctl, bitmap_info);
2058
2059         return 0;
2060 }
2061
2062 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
2063                                struct btrfs_free_space *info, u64 offset,
2064                                u64 bytes, enum btrfs_trim_state trim_state)
2065 {
2066         u64 bytes_to_set = 0;
2067         u64 end;
2068
2069         /*
2070          * This is a tradeoff to make bitmap trim state minimal.  We mark the
2071          * whole bitmap untrimmed if at any point we add untrimmed regions.
2072          */
2073         if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
2074                 if (btrfs_free_space_trimmed(info)) {
2075                         ctl->discardable_extents[BTRFS_STAT_CURR] +=
2076                                 info->bitmap_extents;
2077                         ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
2078                 }
2079                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2080         }
2081
2082         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
2083
2084         bytes_to_set = min(end - offset, bytes);
2085
2086         bitmap_set_bits(ctl, info, offset, bytes_to_set);
2087
2088         /*
2089          * We set some bytes, we have no idea what the max extent size is
2090          * anymore.
2091          */
2092         info->max_extent_size = 0;
2093
2094         return bytes_to_set;
2095
2096 }
2097
2098 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
2099                       struct btrfs_free_space *info)
2100 {
2101         struct btrfs_block_group *block_group = ctl->private;
2102         struct btrfs_fs_info *fs_info = block_group->fs_info;
2103         bool forced = false;
2104
2105 #ifdef CONFIG_BTRFS_DEBUG
2106         if (btrfs_should_fragment_free_space(block_group))
2107                 forced = true;
2108 #endif
2109
2110         /* This is a way to reclaim large regions from the bitmaps. */
2111         if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD)
2112                 return false;
2113
2114         /*
2115          * If we are below the extents threshold then we can add this as an
2116          * extent, and don't have to deal with the bitmap
2117          */
2118         if (!forced && ctl->free_extents < ctl->extents_thresh) {
2119                 /*
2120                  * If this block group has some small extents we don't want to
2121                  * use up all of our free slots in the cache with them, we want
2122                  * to reserve them to larger extents, however if we have plenty
2123                  * of cache left then go ahead an dadd them, no sense in adding
2124                  * the overhead of a bitmap if we don't have to.
2125                  */
2126                 if (info->bytes <= fs_info->sectorsize * 8) {
2127                         if (ctl->free_extents * 3 <= ctl->extents_thresh)
2128                                 return false;
2129                 } else {
2130                         return false;
2131                 }
2132         }
2133
2134         /*
2135          * The original block groups from mkfs can be really small, like 8
2136          * megabytes, so don't bother with a bitmap for those entries.  However
2137          * some block groups can be smaller than what a bitmap would cover but
2138          * are still large enough that they could overflow the 32k memory limit,
2139          * so allow those block groups to still be allowed to have a bitmap
2140          * entry.
2141          */
2142         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length)
2143                 return false;
2144
2145         return true;
2146 }
2147
2148 static const struct btrfs_free_space_op free_space_op = {
2149         .use_bitmap             = use_bitmap,
2150 };
2151
2152 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
2153                               struct btrfs_free_space *info)
2154 {
2155         struct btrfs_free_space *bitmap_info;
2156         struct btrfs_block_group *block_group = NULL;
2157         int added = 0;
2158         u64 bytes, offset, bytes_added;
2159         enum btrfs_trim_state trim_state;
2160         int ret;
2161
2162         bytes = info->bytes;
2163         offset = info->offset;
2164         trim_state = info->trim_state;
2165
2166         if (!ctl->op->use_bitmap(ctl, info))
2167                 return 0;
2168
2169         if (ctl->op == &free_space_op)
2170                 block_group = ctl->private;
2171 again:
2172         /*
2173          * Since we link bitmaps right into the cluster we need to see if we
2174          * have a cluster here, and if so and it has our bitmap we need to add
2175          * the free space to that bitmap.
2176          */
2177         if (block_group && !list_empty(&block_group->cluster_list)) {
2178                 struct btrfs_free_cluster *cluster;
2179                 struct rb_node *node;
2180                 struct btrfs_free_space *entry;
2181
2182                 cluster = list_entry(block_group->cluster_list.next,
2183                                      struct btrfs_free_cluster,
2184                                      block_group_list);
2185                 spin_lock(&cluster->lock);
2186                 node = rb_first(&cluster->root);
2187                 if (!node) {
2188                         spin_unlock(&cluster->lock);
2189                         goto no_cluster_bitmap;
2190                 }
2191
2192                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2193                 if (!entry->bitmap) {
2194                         spin_unlock(&cluster->lock);
2195                         goto no_cluster_bitmap;
2196                 }
2197
2198                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
2199                         bytes_added = add_bytes_to_bitmap(ctl, entry, offset,
2200                                                           bytes, trim_state);
2201                         bytes -= bytes_added;
2202                         offset += bytes_added;
2203                 }
2204                 spin_unlock(&cluster->lock);
2205                 if (!bytes) {
2206                         ret = 1;
2207                         goto out;
2208                 }
2209         }
2210
2211 no_cluster_bitmap:
2212         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2213                                          1, 0);
2214         if (!bitmap_info) {
2215                 ASSERT(added == 0);
2216                 goto new_bitmap;
2217         }
2218
2219         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
2220                                           trim_state);
2221         bytes -= bytes_added;
2222         offset += bytes_added;
2223         added = 0;
2224
2225         if (!bytes) {
2226                 ret = 1;
2227                 goto out;
2228         } else
2229                 goto again;
2230
2231 new_bitmap:
2232         if (info && info->bitmap) {
2233                 add_new_bitmap(ctl, info, offset);
2234                 added = 1;
2235                 info = NULL;
2236                 goto again;
2237         } else {
2238                 spin_unlock(&ctl->tree_lock);
2239
2240                 /* no pre-allocated info, allocate a new one */
2241                 if (!info) {
2242                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
2243                                                  GFP_NOFS);
2244                         if (!info) {
2245                                 spin_lock(&ctl->tree_lock);
2246                                 ret = -ENOMEM;
2247                                 goto out;
2248                         }
2249                 }
2250
2251                 /* allocate the bitmap */
2252                 info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
2253                                                  GFP_NOFS);
2254                 info->trim_state = BTRFS_TRIM_STATE_TRIMMED;
2255                 spin_lock(&ctl->tree_lock);
2256                 if (!info->bitmap) {
2257                         ret = -ENOMEM;
2258                         goto out;
2259                 }
2260                 goto again;
2261         }
2262
2263 out:
2264         if (info) {
2265                 if (info->bitmap)
2266                         kmem_cache_free(btrfs_free_space_bitmap_cachep,
2267                                         info->bitmap);
2268                 kmem_cache_free(btrfs_free_space_cachep, info);
2269         }
2270
2271         return ret;
2272 }
2273
2274 /*
2275  * Free space merging rules:
2276  *  1) Merge trimmed areas together
2277  *  2) Let untrimmed areas coalesce with trimmed areas
2278  *  3) Always pull neighboring regions from bitmaps
2279  *
2280  * The above rules are for when we merge free space based on btrfs_trim_state.
2281  * Rules 2 and 3 are subtle because they are suboptimal, but are done for the
2282  * same reason: to promote larger extent regions which makes life easier for
2283  * find_free_extent().  Rule 2 enables coalescing based on the common path
2284  * being returning free space from btrfs_finish_extent_commit().  So when free
2285  * space is trimmed, it will prevent aggregating trimmed new region and
2286  * untrimmed regions in the rb_tree.  Rule 3 is purely to obtain larger extents
2287  * and provide find_free_extent() with the largest extents possible hoping for
2288  * the reuse path.
2289  */
2290 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2291                           struct btrfs_free_space *info, bool update_stat)
2292 {
2293         struct btrfs_free_space *left_info = NULL;
2294         struct btrfs_free_space *right_info;
2295         bool merged = false;
2296         u64 offset = info->offset;
2297         u64 bytes = info->bytes;
2298         const bool is_trimmed = btrfs_free_space_trimmed(info);
2299
2300         /*
2301          * first we want to see if there is free space adjacent to the range we
2302          * are adding, if there is remove that struct and add a new one to
2303          * cover the entire range
2304          */
2305         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2306         if (right_info && rb_prev(&right_info->offset_index))
2307                 left_info = rb_entry(rb_prev(&right_info->offset_index),
2308                                      struct btrfs_free_space, offset_index);
2309         else if (!right_info)
2310                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2311
2312         /* See try_merge_free_space() comment. */
2313         if (right_info && !right_info->bitmap &&
2314             (!is_trimmed || btrfs_free_space_trimmed(right_info))) {
2315                 if (update_stat)
2316                         unlink_free_space(ctl, right_info);
2317                 else
2318                         __unlink_free_space(ctl, right_info);
2319                 info->bytes += right_info->bytes;
2320                 kmem_cache_free(btrfs_free_space_cachep, right_info);
2321                 merged = true;
2322         }
2323
2324         /* See try_merge_free_space() comment. */
2325         if (left_info && !left_info->bitmap &&
2326             left_info->offset + left_info->bytes == offset &&
2327             (!is_trimmed || btrfs_free_space_trimmed(left_info))) {
2328                 if (update_stat)
2329                         unlink_free_space(ctl, left_info);
2330                 else
2331                         __unlink_free_space(ctl, left_info);
2332                 info->offset = left_info->offset;
2333                 info->bytes += left_info->bytes;
2334                 kmem_cache_free(btrfs_free_space_cachep, left_info);
2335                 merged = true;
2336         }
2337
2338         return merged;
2339 }
2340
2341 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2342                                      struct btrfs_free_space *info,
2343                                      bool update_stat)
2344 {
2345         struct btrfs_free_space *bitmap;
2346         unsigned long i;
2347         unsigned long j;
2348         const u64 end = info->offset + info->bytes;
2349         const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2350         u64 bytes;
2351
2352         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2353         if (!bitmap)
2354                 return false;
2355
2356         i = offset_to_bit(bitmap->offset, ctl->unit, end);
2357         j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2358         if (j == i)
2359                 return false;
2360         bytes = (j - i) * ctl->unit;
2361         info->bytes += bytes;
2362
2363         /* See try_merge_free_space() comment. */
2364         if (!btrfs_free_space_trimmed(bitmap))
2365                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2366
2367         if (update_stat)
2368                 bitmap_clear_bits(ctl, bitmap, end, bytes);
2369         else
2370                 __bitmap_clear_bits(ctl, bitmap, end, bytes);
2371
2372         if (!bitmap->bytes)
2373                 free_bitmap(ctl, bitmap);
2374
2375         return true;
2376 }
2377
2378 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2379                                        struct btrfs_free_space *info,
2380                                        bool update_stat)
2381 {
2382         struct btrfs_free_space *bitmap;
2383         u64 bitmap_offset;
2384         unsigned long i;
2385         unsigned long j;
2386         unsigned long prev_j;
2387         u64 bytes;
2388
2389         bitmap_offset = offset_to_bitmap(ctl, info->offset);
2390         /* If we're on a boundary, try the previous logical bitmap. */
2391         if (bitmap_offset == info->offset) {
2392                 if (info->offset == 0)
2393                         return false;
2394                 bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2395         }
2396
2397         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2398         if (!bitmap)
2399                 return false;
2400
2401         i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2402         j = 0;
2403         prev_j = (unsigned long)-1;
2404         for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2405                 if (j > i)
2406                         break;
2407                 prev_j = j;
2408         }
2409         if (prev_j == i)
2410                 return false;
2411
2412         if (prev_j == (unsigned long)-1)
2413                 bytes = (i + 1) * ctl->unit;
2414         else
2415                 bytes = (i - prev_j) * ctl->unit;
2416
2417         info->offset -= bytes;
2418         info->bytes += bytes;
2419
2420         /* See try_merge_free_space() comment. */
2421         if (!btrfs_free_space_trimmed(bitmap))
2422                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2423
2424         if (update_stat)
2425                 bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2426         else
2427                 __bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2428
2429         if (!bitmap->bytes)
2430                 free_bitmap(ctl, bitmap);
2431
2432         return true;
2433 }
2434
2435 /*
2436  * We prefer always to allocate from extent entries, both for clustered and
2437  * non-clustered allocation requests. So when attempting to add a new extent
2438  * entry, try to see if there's adjacent free space in bitmap entries, and if
2439  * there is, migrate that space from the bitmaps to the extent.
2440  * Like this we get better chances of satisfying space allocation requests
2441  * because we attempt to satisfy them based on a single cache entry, and never
2442  * on 2 or more entries - even if the entries represent a contiguous free space
2443  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2444  * ends).
2445  */
2446 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2447                               struct btrfs_free_space *info,
2448                               bool update_stat)
2449 {
2450         /*
2451          * Only work with disconnected entries, as we can change their offset,
2452          * and must be extent entries.
2453          */
2454         ASSERT(!info->bitmap);
2455         ASSERT(RB_EMPTY_NODE(&info->offset_index));
2456
2457         if (ctl->total_bitmaps > 0) {
2458                 bool stole_end;
2459                 bool stole_front = false;
2460
2461                 stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2462                 if (ctl->total_bitmaps > 0)
2463                         stole_front = steal_from_bitmap_to_front(ctl, info,
2464                                                                  update_stat);
2465
2466                 if (stole_end || stole_front)
2467                         try_merge_free_space(ctl, info, update_stat);
2468         }
2469 }
2470
2471 int __btrfs_add_free_space(struct btrfs_fs_info *fs_info,
2472                            struct btrfs_free_space_ctl *ctl,
2473                            u64 offset, u64 bytes,
2474                            enum btrfs_trim_state trim_state)
2475 {
2476         struct btrfs_block_group *block_group = ctl->private;
2477         struct btrfs_free_space *info;
2478         int ret = 0;
2479         u64 filter_bytes = bytes;
2480
2481         ASSERT(!btrfs_is_zoned(fs_info));
2482
2483         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2484         if (!info)
2485                 return -ENOMEM;
2486
2487         info->offset = offset;
2488         info->bytes = bytes;
2489         info->trim_state = trim_state;
2490         RB_CLEAR_NODE(&info->offset_index);
2491
2492         spin_lock(&ctl->tree_lock);
2493
2494         if (try_merge_free_space(ctl, info, true))
2495                 goto link;
2496
2497         /*
2498          * There was no extent directly to the left or right of this new
2499          * extent then we know we're going to have to allocate a new extent, so
2500          * before we do that see if we need to drop this into a bitmap
2501          */
2502         ret = insert_into_bitmap(ctl, info);
2503         if (ret < 0) {
2504                 goto out;
2505         } else if (ret) {
2506                 ret = 0;
2507                 goto out;
2508         }
2509 link:
2510         /*
2511          * Only steal free space from adjacent bitmaps if we're sure we're not
2512          * going to add the new free space to existing bitmap entries - because
2513          * that would mean unnecessary work that would be reverted. Therefore
2514          * attempt to steal space from bitmaps if we're adding an extent entry.
2515          */
2516         steal_from_bitmap(ctl, info, true);
2517
2518         filter_bytes = max(filter_bytes, info->bytes);
2519
2520         ret = link_free_space(ctl, info);
2521         if (ret)
2522                 kmem_cache_free(btrfs_free_space_cachep, info);
2523 out:
2524         btrfs_discard_update_discardable(block_group);
2525         spin_unlock(&ctl->tree_lock);
2526
2527         if (ret) {
2528                 btrfs_crit(fs_info, "unable to add free space :%d", ret);
2529                 ASSERT(ret != -EEXIST);
2530         }
2531
2532         if (trim_state != BTRFS_TRIM_STATE_TRIMMED) {
2533                 btrfs_discard_check_filter(block_group, filter_bytes);
2534                 btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
2535         }
2536
2537         return ret;
2538 }
2539
2540 static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
2541                                         u64 bytenr, u64 size, bool used)
2542 {
2543         struct btrfs_fs_info *fs_info = block_group->fs_info;
2544         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2545         u64 offset = bytenr - block_group->start;
2546         u64 to_free, to_unusable;
2547
2548         spin_lock(&ctl->tree_lock);
2549         if (!used)
2550                 to_free = size;
2551         else if (offset >= block_group->alloc_offset)
2552                 to_free = size;
2553         else if (offset + size <= block_group->alloc_offset)
2554                 to_free = 0;
2555         else
2556                 to_free = offset + size - block_group->alloc_offset;
2557         to_unusable = size - to_free;
2558
2559         ctl->free_space += to_free;
2560         /*
2561          * If the block group is read-only, we should account freed space into
2562          * bytes_readonly.
2563          */
2564         if (!block_group->ro)
2565                 block_group->zone_unusable += to_unusable;
2566         spin_unlock(&ctl->tree_lock);
2567         if (!used) {
2568                 spin_lock(&block_group->lock);
2569                 block_group->alloc_offset -= size;
2570                 spin_unlock(&block_group->lock);
2571         }
2572
2573         /* All the region is now unusable. Mark it as unused and reclaim */
2574         if (block_group->zone_unusable == block_group->length) {
2575                 btrfs_mark_bg_unused(block_group);
2576         } else if (block_group->zone_unusable >=
2577                    div_factor_fine(block_group->length,
2578                                    fs_info->bg_reclaim_threshold)) {
2579                 btrfs_mark_bg_to_reclaim(block_group);
2580         }
2581
2582         return 0;
2583 }
2584
2585 int btrfs_add_free_space(struct btrfs_block_group *block_group,
2586                          u64 bytenr, u64 size)
2587 {
2588         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2589
2590         if (btrfs_is_zoned(block_group->fs_info))
2591                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2592                                                     true);
2593
2594         if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
2595                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
2596
2597         return __btrfs_add_free_space(block_group->fs_info,
2598                                       block_group->free_space_ctl,
2599                                       bytenr, size, trim_state);
2600 }
2601
2602 int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
2603                                 u64 bytenr, u64 size)
2604 {
2605         if (btrfs_is_zoned(block_group->fs_info))
2606                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2607                                                     false);
2608
2609         return btrfs_add_free_space(block_group, bytenr, size);
2610 }
2611
2612 /*
2613  * This is a subtle distinction because when adding free space back in general,
2614  * we want it to be added as untrimmed for async. But in the case where we add
2615  * it on loading of a block group, we want to consider it trimmed.
2616  */
2617 int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
2618                                        u64 bytenr, u64 size)
2619 {
2620         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2621
2622         if (btrfs_is_zoned(block_group->fs_info))
2623                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2624                                                     true);
2625
2626         if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
2627             btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
2628                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
2629
2630         return __btrfs_add_free_space(block_group->fs_info,
2631                                       block_group->free_space_ctl,
2632                                       bytenr, size, trim_state);
2633 }
2634
2635 int btrfs_remove_free_space(struct btrfs_block_group *block_group,
2636                             u64 offset, u64 bytes)
2637 {
2638         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2639         struct btrfs_free_space *info;
2640         int ret;
2641         bool re_search = false;
2642
2643         if (btrfs_is_zoned(block_group->fs_info)) {
2644                 /*
2645                  * This can happen with conventional zones when replaying log.
2646                  * Since the allocation info of tree-log nodes are not recorded
2647                  * to the extent-tree, calculate_alloc_pointer() failed to
2648                  * advance the allocation pointer after last allocated tree log
2649                  * node blocks.
2650                  *
2651                  * This function is called from
2652                  * btrfs_pin_extent_for_log_replay() when replaying the log.
2653                  * Advance the pointer not to overwrite the tree-log nodes.
2654                  */
2655                 if (block_group->alloc_offset < offset + bytes)
2656                         block_group->alloc_offset = offset + bytes;
2657                 return 0;
2658         }
2659
2660         spin_lock(&ctl->tree_lock);
2661
2662 again:
2663         ret = 0;
2664         if (!bytes)
2665                 goto out_lock;
2666
2667         info = tree_search_offset(ctl, offset, 0, 0);
2668         if (!info) {
2669                 /*
2670                  * oops didn't find an extent that matched the space we wanted
2671                  * to remove, look for a bitmap instead
2672                  */
2673                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2674                                           1, 0);
2675                 if (!info) {
2676                         /*
2677                          * If we found a partial bit of our free space in a
2678                          * bitmap but then couldn't find the other part this may
2679                          * be a problem, so WARN about it.
2680                          */
2681                         WARN_ON(re_search);
2682                         goto out_lock;
2683                 }
2684         }
2685
2686         re_search = false;
2687         if (!info->bitmap) {
2688                 unlink_free_space(ctl, info);
2689                 if (offset == info->offset) {
2690                         u64 to_free = min(bytes, info->bytes);
2691
2692                         info->bytes -= to_free;
2693                         info->offset += to_free;
2694                         if (info->bytes) {
2695                                 ret = link_free_space(ctl, info);
2696                                 WARN_ON(ret);
2697                         } else {
2698                                 kmem_cache_free(btrfs_free_space_cachep, info);
2699                         }
2700
2701                         offset += to_free;
2702                         bytes -= to_free;
2703                         goto again;
2704                 } else {
2705                         u64 old_end = info->bytes + info->offset;
2706
2707                         info->bytes = offset - info->offset;
2708                         ret = link_free_space(ctl, info);
2709                         WARN_ON(ret);
2710                         if (ret)
2711                                 goto out_lock;
2712
2713                         /* Not enough bytes in this entry to satisfy us */
2714                         if (old_end < offset + bytes) {
2715                                 bytes -= old_end - offset;
2716                                 offset = old_end;
2717                                 goto again;
2718                         } else if (old_end == offset + bytes) {
2719                                 /* all done */
2720                                 goto out_lock;
2721                         }
2722                         spin_unlock(&ctl->tree_lock);
2723
2724                         ret = __btrfs_add_free_space(block_group->fs_info, ctl,
2725                                                      offset + bytes,
2726                                                      old_end - (offset + bytes),
2727                                                      info->trim_state);
2728                         WARN_ON(ret);
2729                         goto out;
2730                 }
2731         }
2732
2733         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2734         if (ret == -EAGAIN) {
2735                 re_search = true;
2736                 goto again;
2737         }
2738 out_lock:
2739         btrfs_discard_update_discardable(block_group);
2740         spin_unlock(&ctl->tree_lock);
2741 out:
2742         return ret;
2743 }
2744
2745 void btrfs_dump_free_space(struct btrfs_block_group *block_group,
2746                            u64 bytes)
2747 {
2748         struct btrfs_fs_info *fs_info = block_group->fs_info;
2749         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2750         struct btrfs_free_space *info;
2751         struct rb_node *n;
2752         int count = 0;
2753
2754         /*
2755          * Zoned btrfs does not use free space tree and cluster. Just print
2756          * out the free space after the allocation offset.
2757          */
2758         if (btrfs_is_zoned(fs_info)) {
2759                 btrfs_info(fs_info, "free space %llu",
2760                            block_group->length - block_group->alloc_offset);
2761                 return;
2762         }
2763
2764         spin_lock(&ctl->tree_lock);
2765         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2766                 info = rb_entry(n, struct btrfs_free_space, offset_index);
2767                 if (info->bytes >= bytes && !block_group->ro)
2768                         count++;
2769                 btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
2770                            info->offset, info->bytes,
2771                        (info->bitmap) ? "yes" : "no");
2772         }
2773         spin_unlock(&ctl->tree_lock);
2774         btrfs_info(fs_info, "block group has cluster?: %s",
2775                list_empty(&block_group->cluster_list) ? "no" : "yes");
2776         btrfs_info(fs_info,
2777                    "%d blocks of free space at or bigger than bytes is", count);
2778 }
2779
2780 void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group,
2781                                struct btrfs_free_space_ctl *ctl)
2782 {
2783         struct btrfs_fs_info *fs_info = block_group->fs_info;
2784
2785         spin_lock_init(&ctl->tree_lock);
2786         ctl->unit = fs_info->sectorsize;
2787         ctl->start = block_group->start;
2788         ctl->private = block_group;
2789         ctl->op = &free_space_op;
2790         INIT_LIST_HEAD(&ctl->trimming_ranges);
2791         mutex_init(&ctl->cache_writeout_mutex);
2792
2793         /*
2794          * we only want to have 32k of ram per block group for keeping
2795          * track of free space, and if we pass 1/2 of that we want to
2796          * start converting things over to using bitmaps
2797          */
2798         ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
2799 }
2800
2801 /*
2802  * for a given cluster, put all of its extents back into the free
2803  * space cache.  If the block group passed doesn't match the block group
2804  * pointed to by the cluster, someone else raced in and freed the
2805  * cluster already.  In that case, we just return without changing anything
2806  */
2807 static void __btrfs_return_cluster_to_free_space(
2808                              struct btrfs_block_group *block_group,
2809                              struct btrfs_free_cluster *cluster)
2810 {
2811         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2812         struct btrfs_free_space *entry;
2813         struct rb_node *node;
2814
2815         spin_lock(&cluster->lock);
2816         if (cluster->block_group != block_group) {
2817                 spin_unlock(&cluster->lock);
2818                 return;
2819         }
2820
2821         cluster->block_group = NULL;
2822         cluster->window_start = 0;
2823         list_del_init(&cluster->block_group_list);
2824
2825         node = rb_first(&cluster->root);
2826         while (node) {
2827                 bool bitmap;
2828
2829                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2830                 node = rb_next(&entry->offset_index);
2831                 rb_erase(&entry->offset_index, &cluster->root);
2832                 RB_CLEAR_NODE(&entry->offset_index);
2833
2834                 bitmap = (entry->bitmap != NULL);
2835                 if (!bitmap) {
2836                         /* Merging treats extents as if they were new */
2837                         if (!btrfs_free_space_trimmed(entry)) {
2838                                 ctl->discardable_extents[BTRFS_STAT_CURR]--;
2839                                 ctl->discardable_bytes[BTRFS_STAT_CURR] -=
2840                                         entry->bytes;
2841                         }
2842
2843                         try_merge_free_space(ctl, entry, false);
2844                         steal_from_bitmap(ctl, entry, false);
2845
2846                         /* As we insert directly, update these statistics */
2847                         if (!btrfs_free_space_trimmed(entry)) {
2848                                 ctl->discardable_extents[BTRFS_STAT_CURR]++;
2849                                 ctl->discardable_bytes[BTRFS_STAT_CURR] +=
2850                                         entry->bytes;
2851                         }
2852                 }
2853                 tree_insert_offset(&ctl->free_space_offset,
2854                                    entry->offset, &entry->offset_index, bitmap);
2855         }
2856         cluster->root = RB_ROOT;
2857         spin_unlock(&cluster->lock);
2858         btrfs_put_block_group(block_group);
2859 }
2860
2861 static void __btrfs_remove_free_space_cache_locked(
2862                                 struct btrfs_free_space_ctl *ctl)
2863 {
2864         struct btrfs_free_space *info;
2865         struct rb_node *node;
2866
2867         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2868                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2869                 if (!info->bitmap) {
2870                         unlink_free_space(ctl, info);
2871                         kmem_cache_free(btrfs_free_space_cachep, info);
2872                 } else {
2873                         free_bitmap(ctl, info);
2874                 }
2875
2876                 cond_resched_lock(&ctl->tree_lock);
2877         }
2878 }
2879
2880 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2881 {
2882         spin_lock(&ctl->tree_lock);
2883         __btrfs_remove_free_space_cache_locked(ctl);
2884         if (ctl->private)
2885                 btrfs_discard_update_discardable(ctl->private);
2886         spin_unlock(&ctl->tree_lock);
2887 }
2888
2889 void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group)
2890 {
2891         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2892         struct btrfs_free_cluster *cluster;
2893         struct list_head *head;
2894
2895         spin_lock(&ctl->tree_lock);
2896         while ((head = block_group->cluster_list.next) !=
2897                &block_group->cluster_list) {
2898                 cluster = list_entry(head, struct btrfs_free_cluster,
2899                                      block_group_list);
2900
2901                 WARN_ON(cluster->block_group != block_group);
2902                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2903
2904                 cond_resched_lock(&ctl->tree_lock);
2905         }
2906         __btrfs_remove_free_space_cache_locked(ctl);
2907         btrfs_discard_update_discardable(block_group);
2908         spin_unlock(&ctl->tree_lock);
2909
2910 }
2911
2912 /**
2913  * btrfs_is_free_space_trimmed - see if everything is trimmed
2914  * @block_group: block_group of interest
2915  *
2916  * Walk @block_group's free space rb_tree to determine if everything is trimmed.
2917  */
2918 bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group)
2919 {
2920         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2921         struct btrfs_free_space *info;
2922         struct rb_node *node;
2923         bool ret = true;
2924
2925         spin_lock(&ctl->tree_lock);
2926         node = rb_first(&ctl->free_space_offset);
2927
2928         while (node) {
2929                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2930
2931                 if (!btrfs_free_space_trimmed(info)) {
2932                         ret = false;
2933                         break;
2934                 }
2935
2936                 node = rb_next(node);
2937         }
2938
2939         spin_unlock(&ctl->tree_lock);
2940         return ret;
2941 }
2942
2943 u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
2944                                u64 offset, u64 bytes, u64 empty_size,
2945                                u64 *max_extent_size)
2946 {
2947         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2948         struct btrfs_discard_ctl *discard_ctl =
2949                                         &block_group->fs_info->discard_ctl;
2950         struct btrfs_free_space *entry = NULL;
2951         u64 bytes_search = bytes + empty_size;
2952         u64 ret = 0;
2953         u64 align_gap = 0;
2954         u64 align_gap_len = 0;
2955         enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2956
2957         ASSERT(!btrfs_is_zoned(block_group->fs_info));
2958
2959         spin_lock(&ctl->tree_lock);
2960         entry = find_free_space(ctl, &offset, &bytes_search,
2961                                 block_group->full_stripe_len, max_extent_size);
2962         if (!entry)
2963                 goto out;
2964
2965         ret = offset;
2966         if (entry->bitmap) {
2967                 bitmap_clear_bits(ctl, entry, offset, bytes);
2968
2969                 if (!btrfs_free_space_trimmed(entry))
2970                         atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
2971
2972                 if (!entry->bytes)
2973                         free_bitmap(ctl, entry);
2974         } else {
2975                 unlink_free_space(ctl, entry);
2976                 align_gap_len = offset - entry->offset;
2977                 align_gap = entry->offset;
2978                 align_gap_trim_state = entry->trim_state;
2979
2980                 if (!btrfs_free_space_trimmed(entry))
2981                         atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
2982
2983                 entry->offset = offset + bytes;
2984                 WARN_ON(entry->bytes < bytes + align_gap_len);
2985
2986                 entry->bytes -= bytes + align_gap_len;
2987                 if (!entry->bytes)
2988                         kmem_cache_free(btrfs_free_space_cachep, entry);
2989                 else
2990                         link_free_space(ctl, entry);
2991         }
2992 out:
2993         btrfs_discard_update_discardable(block_group);
2994         spin_unlock(&ctl->tree_lock);
2995
2996         if (align_gap_len)
2997                 __btrfs_add_free_space(block_group->fs_info, ctl,
2998                                        align_gap, align_gap_len,
2999                                        align_gap_trim_state);
3000         return ret;
3001 }
3002
3003 /*
3004  * given a cluster, put all of its extents back into the free space
3005  * cache.  If a block group is passed, this function will only free
3006  * a cluster that belongs to the passed block group.
3007  *
3008  * Otherwise, it'll get a reference on the block group pointed to by the
3009  * cluster and remove the cluster from it.
3010  */
3011 void btrfs_return_cluster_to_free_space(
3012                                struct btrfs_block_group *block_group,
3013                                struct btrfs_free_cluster *cluster)
3014 {
3015         struct btrfs_free_space_ctl *ctl;
3016
3017         /* first, get a safe pointer to the block group */
3018         spin_lock(&cluster->lock);
3019         if (!block_group) {
3020                 block_group = cluster->block_group;
3021                 if (!block_group) {
3022                         spin_unlock(&cluster->lock);
3023                         return;
3024                 }
3025         } else if (cluster->block_group != block_group) {
3026                 /* someone else has already freed it don't redo their work */
3027                 spin_unlock(&cluster->lock);
3028                 return;
3029         }
3030         btrfs_get_block_group(block_group);
3031         spin_unlock(&cluster->lock);
3032
3033         ctl = block_group->free_space_ctl;
3034
3035         /* now return any extents the cluster had on it */
3036         spin_lock(&ctl->tree_lock);
3037         __btrfs_return_cluster_to_free_space(block_group, cluster);
3038         spin_unlock(&ctl->tree_lock);
3039
3040         btrfs_discard_queue_work(&block_group->fs_info->discard_ctl, block_group);
3041
3042         /* finally drop our ref */
3043         btrfs_put_block_group(block_group);
3044 }
3045
3046 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group,
3047                                    struct btrfs_free_cluster *cluster,
3048                                    struct btrfs_free_space *entry,
3049                                    u64 bytes, u64 min_start,
3050                                    u64 *max_extent_size)
3051 {
3052         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3053         int err;
3054         u64 search_start = cluster->window_start;
3055         u64 search_bytes = bytes;
3056         u64 ret = 0;
3057
3058         search_start = min_start;
3059         search_bytes = bytes;
3060
3061         err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
3062         if (err) {
3063                 *max_extent_size = max(get_max_extent_size(entry),
3064                                        *max_extent_size);
3065                 return 0;
3066         }
3067
3068         ret = search_start;
3069         __bitmap_clear_bits(ctl, entry, ret, bytes);
3070
3071         return ret;
3072 }
3073
3074 /*
3075  * given a cluster, try to allocate 'bytes' from it, returns 0
3076  * if it couldn't find anything suitably large, or a logical disk offset
3077  * if things worked out
3078  */
3079 u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
3080                              struct btrfs_free_cluster *cluster, u64 bytes,
3081                              u64 min_start, u64 *max_extent_size)
3082 {
3083         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3084         struct btrfs_discard_ctl *discard_ctl =
3085                                         &block_group->fs_info->discard_ctl;
3086         struct btrfs_free_space *entry = NULL;
3087         struct rb_node *node;
3088         u64 ret = 0;
3089
3090         ASSERT(!btrfs_is_zoned(block_group->fs_info));
3091
3092         spin_lock(&cluster->lock);
3093         if (bytes > cluster->max_size)
3094                 goto out;
3095
3096         if (cluster->block_group != block_group)
3097                 goto out;
3098
3099         node = rb_first(&cluster->root);
3100         if (!node)
3101                 goto out;
3102
3103         entry = rb_entry(node, struct btrfs_free_space, offset_index);
3104         while (1) {
3105                 if (entry->bytes < bytes)
3106                         *max_extent_size = max(get_max_extent_size(entry),
3107                                                *max_extent_size);
3108
3109                 if (entry->bytes < bytes ||
3110                     (!entry->bitmap && entry->offset < min_start)) {
3111                         node = rb_next(&entry->offset_index);
3112                         if (!node)
3113                                 break;
3114                         entry = rb_entry(node, struct btrfs_free_space,
3115                                          offset_index);
3116                         continue;
3117                 }
3118
3119                 if (entry->bitmap) {
3120                         ret = btrfs_alloc_from_bitmap(block_group,
3121                                                       cluster, entry, bytes,
3122                                                       cluster->window_start,
3123                                                       max_extent_size);
3124                         if (ret == 0) {
3125                                 node = rb_next(&entry->offset_index);
3126                                 if (!node)
3127                                         break;
3128                                 entry = rb_entry(node, struct btrfs_free_space,
3129                                                  offset_index);
3130                                 continue;
3131                         }
3132                         cluster->window_start += bytes;
3133                 } else {
3134                         ret = entry->offset;
3135
3136                         entry->offset += bytes;
3137                         entry->bytes -= bytes;
3138                 }
3139
3140                 break;
3141         }
3142 out:
3143         spin_unlock(&cluster->lock);
3144
3145         if (!ret)
3146                 return 0;
3147
3148         spin_lock(&ctl->tree_lock);
3149
3150         if (!btrfs_free_space_trimmed(entry))
3151                 atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3152
3153         ctl->free_space -= bytes;
3154         if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
3155                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
3156
3157         spin_lock(&cluster->lock);
3158         if (entry->bytes == 0) {
3159                 rb_erase(&entry->offset_index, &cluster->root);
3160                 ctl->free_extents--;
3161                 if (entry->bitmap) {
3162                         kmem_cache_free(btrfs_free_space_bitmap_cachep,
3163                                         entry->bitmap);
3164                         ctl->total_bitmaps--;
3165                         recalculate_thresholds(ctl);
3166                 } else if (!btrfs_free_space_trimmed(entry)) {
3167                         ctl->discardable_extents[BTRFS_STAT_CURR]--;
3168                 }
3169                 kmem_cache_free(btrfs_free_space_cachep, entry);
3170         }
3171
3172         spin_unlock(&cluster->lock);
3173         spin_unlock(&ctl->tree_lock);
3174
3175         return ret;
3176 }
3177
3178 static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group,
3179                                 struct btrfs_free_space *entry,
3180                                 struct btrfs_free_cluster *cluster,
3181                                 u64 offset, u64 bytes,
3182                                 u64 cont1_bytes, u64 min_bytes)
3183 {
3184         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3185         unsigned long next_zero;
3186         unsigned long i;
3187         unsigned long want_bits;
3188         unsigned long min_bits;
3189         unsigned long found_bits;
3190         unsigned long max_bits = 0;
3191         unsigned long start = 0;
3192         unsigned long total_found = 0;
3193         int ret;
3194
3195         i = offset_to_bit(entry->offset, ctl->unit,
3196                           max_t(u64, offset, entry->offset));
3197         want_bits = bytes_to_bits(bytes, ctl->unit);
3198         min_bits = bytes_to_bits(min_bytes, ctl->unit);
3199
3200         /*
3201          * Don't bother looking for a cluster in this bitmap if it's heavily
3202          * fragmented.
3203          */
3204         if (entry->max_extent_size &&
3205             entry->max_extent_size < cont1_bytes)
3206                 return -ENOSPC;
3207 again:
3208         found_bits = 0;
3209         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
3210                 next_zero = find_next_zero_bit(entry->bitmap,
3211                                                BITS_PER_BITMAP, i);
3212                 if (next_zero - i >= min_bits) {
3213                         found_bits = next_zero - i;
3214                         if (found_bits > max_bits)
3215                                 max_bits = found_bits;
3216                         break;
3217                 }
3218                 if (next_zero - i > max_bits)
3219                         max_bits = next_zero - i;
3220                 i = next_zero;
3221         }
3222
3223         if (!found_bits) {
3224                 entry->max_extent_size = (u64)max_bits * ctl->unit;
3225                 return -ENOSPC;
3226         }
3227
3228         if (!total_found) {
3229                 start = i;
3230                 cluster->max_size = 0;
3231         }
3232
3233         total_found += found_bits;
3234
3235         if (cluster->max_size < found_bits * ctl->unit)
3236                 cluster->max_size = found_bits * ctl->unit;
3237
3238         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
3239                 i = next_zero + 1;
3240                 goto again;
3241         }
3242
3243         cluster->window_start = start * ctl->unit + entry->offset;
3244         rb_erase(&entry->offset_index, &ctl->free_space_offset);
3245         ret = tree_insert_offset(&cluster->root, entry->offset,
3246                                  &entry->offset_index, 1);
3247         ASSERT(!ret); /* -EEXIST; Logic error */
3248
3249         trace_btrfs_setup_cluster(block_group, cluster,
3250                                   total_found * ctl->unit, 1);
3251         return 0;
3252 }
3253
3254 /*
3255  * This searches the block group for just extents to fill the cluster with.
3256  * Try to find a cluster with at least bytes total bytes, at least one
3257  * extent of cont1_bytes, and other clusters of at least min_bytes.
3258  */
3259 static noinline int
3260 setup_cluster_no_bitmap(struct btrfs_block_group *block_group,
3261                         struct btrfs_free_cluster *cluster,
3262                         struct list_head *bitmaps, u64 offset, u64 bytes,
3263                         u64 cont1_bytes, u64 min_bytes)
3264 {
3265         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3266         struct btrfs_free_space *first = NULL;
3267         struct btrfs_free_space *entry = NULL;
3268         struct btrfs_free_space *last;
3269         struct rb_node *node;
3270         u64 window_free;
3271         u64 max_extent;
3272         u64 total_size = 0;
3273
3274         entry = tree_search_offset(ctl, offset, 0, 1);
3275         if (!entry)
3276                 return -ENOSPC;
3277
3278         /*
3279          * We don't want bitmaps, so just move along until we find a normal
3280          * extent entry.
3281          */
3282         while (entry->bitmap || entry->bytes < min_bytes) {
3283                 if (entry->bitmap && list_empty(&entry->list))
3284                         list_add_tail(&entry->list, bitmaps);
3285                 node = rb_next(&entry->offset_index);
3286                 if (!node)
3287                         return -ENOSPC;
3288                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
3289         }
3290
3291         window_free = entry->bytes;
3292         max_extent = entry->bytes;
3293         first = entry;
3294         last = entry;
3295
3296         for (node = rb_next(&entry->offset_index); node;
3297              node = rb_next(&entry->offset_index)) {
3298                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
3299
3300                 if (entry->bitmap) {
3301                         if (list_empty(&entry->list))
3302                                 list_add_tail(&entry->list, bitmaps);
3303                         continue;
3304                 }
3305
3306                 if (entry->bytes < min_bytes)
3307                         continue;
3308
3309                 last = entry;
3310                 window_free += entry->bytes;
3311                 if (entry->bytes > max_extent)
3312                         max_extent = entry->bytes;
3313         }
3314
3315         if (window_free < bytes || max_extent < cont1_bytes)
3316                 return -ENOSPC;
3317
3318         cluster->window_start = first->offset;
3319
3320         node = &first->offset_index;
3321
3322         /*
3323          * now we've found our entries, pull them out of the free space
3324          * cache and put them into the cluster rbtree
3325          */
3326         do {
3327                 int ret;
3328
3329                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
3330                 node = rb_next(&entry->offset_index);
3331                 if (entry->bitmap || entry->bytes < min_bytes)
3332                         continue;
3333
3334                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
3335                 ret = tree_insert_offset(&cluster->root, entry->offset,
3336                                          &entry->offset_index, 0);
3337                 total_size += entry->bytes;
3338                 ASSERT(!ret); /* -EEXIST; Logic error */
3339         } while (node && entry != last);
3340
3341         cluster->max_size = max_extent;
3342         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
3343         return 0;
3344 }
3345
3346 /*
3347  * This specifically looks for bitmaps that may work in the cluster, we assume
3348  * that we have already failed to find extents that will work.
3349  */
3350 static noinline int
3351 setup_cluster_bitmap(struct btrfs_block_group *block_group,
3352                      struct btrfs_free_cluster *cluster,
3353                      struct list_head *bitmaps, u64 offset, u64 bytes,
3354                      u64 cont1_bytes, u64 min_bytes)
3355 {
3356         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3357         struct btrfs_free_space *entry = NULL;
3358         int ret = -ENOSPC;
3359         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
3360
3361         if (ctl->total_bitmaps == 0)
3362                 return -ENOSPC;
3363
3364         /*
3365          * The bitmap that covers offset won't be in the list unless offset
3366          * is just its start offset.
3367          */
3368         if (!list_empty(bitmaps))
3369                 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
3370
3371         if (!entry || entry->offset != bitmap_offset) {
3372                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
3373                 if (entry && list_empty(&entry->list))
3374                         list_add(&entry->list, bitmaps);
3375         }
3376
3377         list_for_each_entry(entry, bitmaps, list) {
3378                 if (entry->bytes < bytes)
3379                         continue;
3380                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
3381                                            bytes, cont1_bytes, min_bytes);
3382                 if (!ret)
3383                         return 0;
3384         }
3385
3386         /*
3387          * The bitmaps list has all the bitmaps that record free space
3388          * starting after offset, so no more search is required.
3389          */
3390         return -ENOSPC;
3391 }
3392
3393 /*
3394  * here we try to find a cluster of blocks in a block group.  The goal
3395  * is to find at least bytes+empty_size.
3396  * We might not find them all in one contiguous area.
3397  *
3398  * returns zero and sets up cluster if things worked out, otherwise
3399  * it returns -enospc
3400  */
3401 int btrfs_find_space_cluster(struct btrfs_block_group *block_group,
3402                              struct btrfs_free_cluster *cluster,
3403                              u64 offset, u64 bytes, u64 empty_size)
3404 {
3405         struct btrfs_fs_info *fs_info = block_group->fs_info;
3406         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3407         struct btrfs_free_space *entry, *tmp;
3408         LIST_HEAD(bitmaps);
3409         u64 min_bytes;
3410         u64 cont1_bytes;
3411         int ret;
3412
3413         /*
3414          * Choose the minimum extent size we'll require for this
3415          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
3416          * For metadata, allow allocates with smaller extents.  For
3417          * data, keep it dense.
3418          */
3419         if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
3420                 cont1_bytes = min_bytes = bytes + empty_size;
3421         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
3422                 cont1_bytes = bytes;
3423                 min_bytes = fs_info->sectorsize;
3424         } else {
3425                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3426                 min_bytes = fs_info->sectorsize;
3427         }
3428
3429         spin_lock(&ctl->tree_lock);
3430
3431         /*
3432          * If we know we don't have enough space to make a cluster don't even
3433          * bother doing all the work to try and find one.
3434          */
3435         if (ctl->free_space < bytes) {
3436                 spin_unlock(&ctl->tree_lock);
3437                 return -ENOSPC;
3438         }
3439
3440         spin_lock(&cluster->lock);
3441
3442         /* someone already found a cluster, hooray */
3443         if (cluster->block_group) {
3444                 ret = 0;
3445                 goto out;
3446         }
3447
3448         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3449                                  min_bytes);
3450
3451         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3452                                       bytes + empty_size,
3453                                       cont1_bytes, min_bytes);
3454         if (ret)
3455                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3456                                            offset, bytes + empty_size,
3457                                            cont1_bytes, min_bytes);
3458
3459         /* Clear our temporary list */
3460         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3461                 list_del_init(&entry->list);
3462
3463         if (!ret) {
3464                 btrfs_get_block_group(block_group);
3465                 list_add_tail(&cluster->block_group_list,
3466                               &block_group->cluster_list);
3467                 cluster->block_group = block_group;
3468         } else {
3469                 trace_btrfs_failed_cluster_setup(block_group);
3470         }
3471 out:
3472         spin_unlock(&cluster->lock);
3473         spin_unlock(&ctl->tree_lock);
3474
3475         return ret;
3476 }
3477
3478 /*
3479  * simple code to zero out a cluster
3480  */
3481 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3482 {
3483         spin_lock_init(&cluster->lock);
3484         spin_lock_init(&cluster->refill_lock);
3485         cluster->root = RB_ROOT;
3486         cluster->max_size = 0;
3487         cluster->fragmented = false;
3488         INIT_LIST_HEAD(&cluster->block_group_list);
3489         cluster->block_group = NULL;
3490 }
3491
3492 static int do_trimming(struct btrfs_block_group *block_group,
3493                        u64 *total_trimmed, u64 start, u64 bytes,
3494                        u64 reserved_start, u64 reserved_bytes,
3495                        enum btrfs_trim_state reserved_trim_state,
3496                        struct btrfs_trim_range *trim_entry)
3497 {
3498         struct btrfs_space_info *space_info = block_group->space_info;
3499         struct btrfs_fs_info *fs_info = block_group->fs_info;
3500         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3501         int ret;
3502         int update = 0;
3503         const u64 end = start + bytes;
3504         const u64 reserved_end = reserved_start + reserved_bytes;
3505         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3506         u64 trimmed = 0;
3507
3508         spin_lock(&space_info->lock);
3509         spin_lock(&block_group->lock);
3510         if (!block_group->ro) {
3511                 block_group->reserved += reserved_bytes;
3512                 space_info->bytes_reserved += reserved_bytes;
3513                 update = 1;
3514         }
3515         spin_unlock(&block_group->lock);
3516         spin_unlock(&space_info->lock);
3517
3518         ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed);
3519         if (!ret) {
3520                 *total_trimmed += trimmed;
3521                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
3522         }
3523
3524         mutex_lock(&ctl->cache_writeout_mutex);
3525         if (reserved_start < start)
3526                 __btrfs_add_free_space(fs_info, ctl, reserved_start,
3527                                        start - reserved_start,
3528                                        reserved_trim_state);
3529         if (start + bytes < reserved_start + reserved_bytes)
3530                 __btrfs_add_free_space(fs_info, ctl, end, reserved_end - end,
3531                                        reserved_trim_state);
3532         __btrfs_add_free_space(fs_info, ctl, start, bytes, trim_state);
3533         list_del(&trim_entry->list);
3534         mutex_unlock(&ctl->cache_writeout_mutex);
3535
3536         if (update) {
3537                 spin_lock(&space_info->lock);
3538                 spin_lock(&block_group->lock);
3539                 if (block_group->ro)
3540                         space_info->bytes_readonly += reserved_bytes;
3541                 block_group->reserved -= reserved_bytes;
3542                 space_info->bytes_reserved -= reserved_bytes;
3543                 spin_unlock(&block_group->lock);
3544                 spin_unlock(&space_info->lock);
3545         }
3546
3547         return ret;
3548 }
3549
3550 /*
3551  * If @async is set, then we will trim 1 region and return.
3552  */
3553 static int trim_no_bitmap(struct btrfs_block_group *block_group,
3554                           u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3555                           bool async)
3556 {
3557         struct btrfs_discard_ctl *discard_ctl =
3558                                         &block_group->fs_info->discard_ctl;
3559         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3560         struct btrfs_free_space *entry;
3561         struct rb_node *node;
3562         int ret = 0;
3563         u64 extent_start;
3564         u64 extent_bytes;
3565         enum btrfs_trim_state extent_trim_state;
3566         u64 bytes;
3567         const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3568
3569         while (start < end) {
3570                 struct btrfs_trim_range trim_entry;
3571
3572                 mutex_lock(&ctl->cache_writeout_mutex);
3573                 spin_lock(&ctl->tree_lock);
3574
3575                 if (ctl->free_space < minlen)
3576                         goto out_unlock;
3577
3578                 entry = tree_search_offset(ctl, start, 0, 1);
3579                 if (!entry)
3580                         goto out_unlock;
3581
3582                 /* Skip bitmaps and if async, already trimmed entries */
3583                 while (entry->bitmap ||
3584                        (async && btrfs_free_space_trimmed(entry))) {
3585                         node = rb_next(&entry->offset_index);
3586                         if (!node)
3587                                 goto out_unlock;
3588                         entry = rb_entry(node, struct btrfs_free_space,
3589                                          offset_index);
3590                 }
3591
3592                 if (entry->offset >= end)
3593                         goto out_unlock;
3594
3595                 extent_start = entry->offset;
3596                 extent_bytes = entry->bytes;
3597                 extent_trim_state = entry->trim_state;
3598                 if (async) {
3599                         start = entry->offset;
3600                         bytes = entry->bytes;
3601                         if (bytes < minlen) {
3602                                 spin_unlock(&ctl->tree_lock);
3603                                 mutex_unlock(&ctl->cache_writeout_mutex);
3604                                 goto next;
3605                         }
3606                         unlink_free_space(ctl, entry);
3607                         /*
3608                          * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3609                          * If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim
3610                          * X when we come back around.  So trim it now.
3611                          */
3612                         if (max_discard_size &&
3613                             bytes >= (max_discard_size +
3614                                       BTRFS_ASYNC_DISCARD_MIN_FILTER)) {
3615                                 bytes = max_discard_size;
3616                                 extent_bytes = max_discard_size;
3617                                 entry->offset += max_discard_size;
3618                                 entry->bytes -= max_discard_size;
3619                                 link_free_space(ctl, entry);
3620                         } else {
3621                                 kmem_cache_free(btrfs_free_space_cachep, entry);
3622                         }
3623                 } else {
3624                         start = max(start, extent_start);
3625                         bytes = min(extent_start + extent_bytes, end) - start;
3626                         if (bytes < minlen) {
3627                                 spin_unlock(&ctl->tree_lock);
3628                                 mutex_unlock(&ctl->cache_writeout_mutex);
3629                                 goto next;
3630                         }
3631
3632                         unlink_free_space(ctl, entry);
3633                         kmem_cache_free(btrfs_free_space_cachep, entry);
3634                 }
3635
3636                 spin_unlock(&ctl->tree_lock);
3637                 trim_entry.start = extent_start;
3638                 trim_entry.bytes = extent_bytes;
3639                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3640                 mutex_unlock(&ctl->cache_writeout_mutex);
3641
3642                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3643                                   extent_start, extent_bytes, extent_trim_state,
3644                                   &trim_entry);
3645                 if (ret) {
3646                         block_group->discard_cursor = start + bytes;
3647                         break;
3648                 }
3649 next:
3650                 start += bytes;
3651                 block_group->discard_cursor = start;
3652                 if (async && *total_trimmed)
3653                         break;
3654
3655                 if (fatal_signal_pending(current)) {
3656                         ret = -ERESTARTSYS;
3657                         break;
3658                 }
3659
3660                 cond_resched();
3661         }
3662
3663         return ret;
3664
3665 out_unlock:
3666         block_group->discard_cursor = btrfs_block_group_end(block_group);
3667         spin_unlock(&ctl->tree_lock);
3668         mutex_unlock(&ctl->cache_writeout_mutex);
3669
3670         return ret;
3671 }
3672
3673 /*
3674  * If we break out of trimming a bitmap prematurely, we should reset the
3675  * trimming bit.  In a rather contrieved case, it's possible to race here so
3676  * reset the state to BTRFS_TRIM_STATE_UNTRIMMED.
3677  *
3678  * start = start of bitmap
3679  * end = near end of bitmap
3680  *
3681  * Thread 1:                    Thread 2:
3682  * trim_bitmaps(start)
3683  *                              trim_bitmaps(end)
3684  *                              end_trimming_bitmap()
3685  * reset_trimming_bitmap()
3686  */
3687 static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
3688 {
3689         struct btrfs_free_space *entry;
3690
3691         spin_lock(&ctl->tree_lock);
3692         entry = tree_search_offset(ctl, offset, 1, 0);
3693         if (entry) {
3694                 if (btrfs_free_space_trimmed(entry)) {
3695                         ctl->discardable_extents[BTRFS_STAT_CURR] +=
3696                                 entry->bitmap_extents;
3697                         ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
3698                 }
3699                 entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3700         }
3701
3702         spin_unlock(&ctl->tree_lock);
3703 }
3704
3705 static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
3706                                 struct btrfs_free_space *entry)
3707 {
3708         if (btrfs_free_space_trimming_bitmap(entry)) {
3709                 entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
3710                 ctl->discardable_extents[BTRFS_STAT_CURR] -=
3711                         entry->bitmap_extents;
3712                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
3713         }
3714 }
3715
3716 /*
3717  * If @async is set, then we will trim 1 region and return.
3718  */
3719 static int trim_bitmaps(struct btrfs_block_group *block_group,
3720                         u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3721                         u64 maxlen, bool async)
3722 {
3723         struct btrfs_discard_ctl *discard_ctl =
3724                                         &block_group->fs_info->discard_ctl;
3725         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3726         struct btrfs_free_space *entry;
3727         int ret = 0;
3728         int ret2;
3729         u64 bytes;
3730         u64 offset = offset_to_bitmap(ctl, start);
3731         const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3732
3733         while (offset < end) {
3734                 bool next_bitmap = false;
3735                 struct btrfs_trim_range trim_entry;
3736
3737                 mutex_lock(&ctl->cache_writeout_mutex);
3738                 spin_lock(&ctl->tree_lock);
3739
3740                 if (ctl->free_space < minlen) {
3741                         block_group->discard_cursor =
3742                                 btrfs_block_group_end(block_group);
3743                         spin_unlock(&ctl->tree_lock);
3744                         mutex_unlock(&ctl->cache_writeout_mutex);
3745                         break;
3746                 }
3747
3748                 entry = tree_search_offset(ctl, offset, 1, 0);
3749                 /*
3750                  * Bitmaps are marked trimmed lossily now to prevent constant
3751                  * discarding of the same bitmap (the reason why we are bound
3752                  * by the filters).  So, retrim the block group bitmaps when we
3753                  * are preparing to punt to the unused_bgs list.  This uses
3754                  * @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED
3755                  * which is the only discard index which sets minlen to 0.
3756                  */
3757                 if (!entry || (async && minlen && start == offset &&
3758                                btrfs_free_space_trimmed(entry))) {
3759                         spin_unlock(&ctl->tree_lock);
3760                         mutex_unlock(&ctl->cache_writeout_mutex);
3761                         next_bitmap = true;
3762                         goto next;
3763                 }
3764
3765                 /*
3766                  * Async discard bitmap trimming begins at by setting the start
3767                  * to be key.objectid and the offset_to_bitmap() aligns to the
3768                  * start of the bitmap.  This lets us know we are fully
3769                  * scanning the bitmap rather than only some portion of it.
3770                  */
3771                 if (start == offset)
3772                         entry->trim_state = BTRFS_TRIM_STATE_TRIMMING;
3773
3774                 bytes = minlen;
3775                 ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
3776                 if (ret2 || start >= end) {
3777                         /*
3778                          * We lossily consider a bitmap trimmed if we only skip
3779                          * over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER.
3780                          */
3781                         if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER)
3782                                 end_trimming_bitmap(ctl, entry);
3783                         else
3784                                 entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3785                         spin_unlock(&ctl->tree_lock);
3786                         mutex_unlock(&ctl->cache_writeout_mutex);
3787                         next_bitmap = true;
3788                         goto next;
3789                 }
3790
3791                 /*
3792                  * We already trimmed a region, but are using the locking above
3793                  * to reset the trim_state.
3794                  */
3795                 if (async && *total_trimmed) {
3796                         spin_unlock(&ctl->tree_lock);
3797                         mutex_unlock(&ctl->cache_writeout_mutex);
3798                         goto out;
3799                 }
3800
3801                 bytes = min(bytes, end - start);
3802                 if (bytes < minlen || (async && maxlen && bytes > maxlen)) {
3803                         spin_unlock(&ctl->tree_lock);
3804                         mutex_unlock(&ctl->cache_writeout_mutex);
3805                         goto next;
3806                 }
3807
3808                 /*
3809                  * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3810                  * If X < @minlen, we won't trim X when we come back around.
3811                  * So trim it now.  We differ here from trimming extents as we
3812                  * don't keep individual state per bit.
3813                  */
3814                 if (async &&
3815                     max_discard_size &&
3816                     bytes > (max_discard_size + minlen))
3817                         bytes = max_discard_size;
3818
3819                 bitmap_clear_bits(ctl, entry, start, bytes);
3820                 if (entry->bytes == 0)
3821                         free_bitmap(ctl, entry);
3822
3823                 spin_unlock(&ctl->tree_lock);
3824                 trim_entry.start = start;
3825                 trim_entry.bytes = bytes;
3826                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3827                 mutex_unlock(&ctl->cache_writeout_mutex);
3828
3829                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3830                                   start, bytes, 0, &trim_entry);
3831                 if (ret) {
3832                         reset_trimming_bitmap(ctl, offset);
3833                         block_group->discard_cursor =
3834                                 btrfs_block_group_end(block_group);
3835                         break;
3836                 }
3837 next:
3838                 if (next_bitmap) {
3839                         offset += BITS_PER_BITMAP * ctl->unit;
3840                         start = offset;
3841                 } else {
3842                         start += bytes;
3843                 }
3844                 block_group->discard_cursor = start;
3845
3846                 if (fatal_signal_pending(current)) {
3847                         if (start != offset)
3848                                 reset_trimming_bitmap(ctl, offset);
3849                         ret = -ERESTARTSYS;
3850                         break;
3851                 }
3852
3853                 cond_resched();
3854         }
3855
3856         if (offset >= end)
3857                 block_group->discard_cursor = end;
3858
3859 out:
3860         return ret;
3861 }
3862
3863 int btrfs_trim_block_group(struct btrfs_block_group *block_group,
3864                            u64 *trimmed, u64 start, u64 end, u64 minlen)
3865 {
3866         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3867         int ret;
3868         u64 rem = 0;
3869
3870         ASSERT(!btrfs_is_zoned(block_group->fs_info));
3871
3872         *trimmed = 0;
3873
3874         spin_lock(&block_group->lock);
3875         if (block_group->removed) {
3876                 spin_unlock(&block_group->lock);
3877                 return 0;
3878         }
3879         btrfs_freeze_block_group(block_group);
3880         spin_unlock(&block_group->lock);
3881
3882         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, false);
3883         if (ret)
3884                 goto out;
3885
3886         ret = trim_bitmaps(block_group, trimmed, start, end, minlen, 0, false);
3887         div64_u64_rem(end, BITS_PER_BITMAP * ctl->unit, &rem);
3888         /* If we ended in the middle of a bitmap, reset the trimming flag */
3889         if (rem)
3890                 reset_trimming_bitmap(ctl, offset_to_bitmap(ctl, end));
3891 out:
3892         btrfs_unfreeze_block_group(block_group);
3893         return ret;
3894 }
3895
3896 int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group,
3897                                    u64 *trimmed, u64 start, u64 end, u64 minlen,
3898                                    bool async)
3899 {
3900         int ret;
3901
3902         *trimmed = 0;
3903
3904         spin_lock(&block_group->lock);
3905         if (block_group->removed) {
3906                 spin_unlock(&block_group->lock);
3907                 return 0;
3908         }
3909         btrfs_freeze_block_group(block_group);
3910         spin_unlock(&block_group->lock);
3911
3912         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, async);
3913         btrfs_unfreeze_block_group(block_group);
3914
3915         return ret;
3916 }
3917
3918 int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
3919                                    u64 *trimmed, u64 start, u64 end, u64 minlen,
3920                                    u64 maxlen, bool async)
3921 {
3922         int ret;
3923
3924         *trimmed = 0;
3925
3926         spin_lock(&block_group->lock);
3927         if (block_group->removed) {
3928                 spin_unlock(&block_group->lock);
3929                 return 0;
3930         }
3931         btrfs_freeze_block_group(block_group);
3932         spin_unlock(&block_group->lock);
3933
3934         ret = trim_bitmaps(block_group, trimmed, start, end, minlen, maxlen,
3935                            async);
3936
3937         btrfs_unfreeze_block_group(block_group);
3938
3939         return ret;
3940 }
3941
3942 bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
3943 {
3944         return btrfs_super_cache_generation(fs_info->super_copy);
3945 }
3946
3947 static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info,
3948                                        struct btrfs_trans_handle *trans)
3949 {
3950         struct btrfs_block_group *block_group;
3951         struct rb_node *node;
3952         int ret = 0;
3953
3954         btrfs_info(fs_info, "cleaning free space cache v1");
3955
3956         node = rb_first(&fs_info->block_group_cache_tree);
3957         while (node) {
3958                 block_group = rb_entry(node, struct btrfs_block_group, cache_node);
3959                 ret = btrfs_remove_free_space_inode(trans, NULL, block_group);
3960                 if (ret)
3961                         goto out;
3962                 node = rb_next(node);
3963         }
3964 out:
3965         return ret;
3966 }
3967
3968 int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active)
3969 {
3970         struct btrfs_trans_handle *trans;
3971         int ret;
3972
3973         /*
3974          * update_super_roots will appropriately set or unset
3975          * super_copy->cache_generation based on SPACE_CACHE and
3976          * BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a
3977          * transaction commit whether we are enabling space cache v1 and don't
3978          * have any other work to do, or are disabling it and removing free
3979          * space inodes.
3980          */
3981         trans = btrfs_start_transaction(fs_info->tree_root, 0);
3982         if (IS_ERR(trans))
3983                 return PTR_ERR(trans);
3984
3985         if (!active) {
3986                 set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
3987                 ret = cleanup_free_space_cache_v1(fs_info, trans);
3988                 if (ret) {
3989                         btrfs_abort_transaction(trans, ret);
3990                         btrfs_end_transaction(trans);
3991                         goto out;
3992                 }
3993         }
3994
3995         ret = btrfs_commit_transaction(trans);
3996 out:
3997         clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
3998
3999         return ret;
4000 }
4001
4002 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4003 /*
4004  * Use this if you need to make a bitmap or extent entry specifically, it
4005  * doesn't do any of the merging that add_free_space does, this acts a lot like
4006  * how the free space cache loading stuff works, so you can get really weird
4007  * configurations.
4008  */
4009 int test_add_free_space_entry(struct btrfs_block_group *cache,
4010                               u64 offset, u64 bytes, bool bitmap)
4011 {
4012         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4013         struct btrfs_free_space *info = NULL, *bitmap_info;
4014         void *map = NULL;
4015         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED;
4016         u64 bytes_added;
4017         int ret;
4018
4019 again:
4020         if (!info) {
4021                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
4022                 if (!info)
4023                         return -ENOMEM;
4024         }
4025
4026         if (!bitmap) {
4027                 spin_lock(&ctl->tree_lock);
4028                 info->offset = offset;
4029                 info->bytes = bytes;
4030                 info->max_extent_size = 0;
4031                 ret = link_free_space(ctl, info);
4032                 spin_unlock(&ctl->tree_lock);
4033                 if (ret)
4034                         kmem_cache_free(btrfs_free_space_cachep, info);
4035                 return ret;
4036         }
4037
4038         if (!map) {
4039                 map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
4040                 if (!map) {
4041                         kmem_cache_free(btrfs_free_space_cachep, info);
4042                         return -ENOMEM;
4043                 }
4044         }
4045
4046         spin_lock(&ctl->tree_lock);
4047         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4048                                          1, 0);
4049         if (!bitmap_info) {
4050                 info->bitmap = map;
4051                 map = NULL;
4052                 add_new_bitmap(ctl, info, offset);
4053                 bitmap_info = info;
4054                 info = NULL;
4055         }
4056
4057         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
4058                                           trim_state);
4059
4060         bytes -= bytes_added;
4061         offset += bytes_added;
4062         spin_unlock(&ctl->tree_lock);
4063
4064         if (bytes)
4065                 goto again;
4066
4067         if (info)
4068                 kmem_cache_free(btrfs_free_space_cachep, info);
4069         if (map)
4070                 kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
4071         return 0;
4072 }
4073
4074 /*
4075  * Checks to see if the given range is in the free space cache.  This is really
4076  * just used to check the absence of space, so if there is free space in the
4077  * range at all we will return 1.
4078  */
4079 int test_check_exists(struct btrfs_block_group *cache,
4080                       u64 offset, u64 bytes)
4081 {
4082         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4083         struct btrfs_free_space *info;
4084         int ret = 0;
4085
4086         spin_lock(&ctl->tree_lock);
4087         info = tree_search_offset(ctl, offset, 0, 0);
4088         if (!info) {
4089                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4090                                           1, 0);
4091                 if (!info)
4092                         goto out;
4093         }
4094
4095 have_info:
4096         if (info->bitmap) {
4097                 u64 bit_off, bit_bytes;
4098                 struct rb_node *n;
4099                 struct btrfs_free_space *tmp;
4100
4101                 bit_off = offset;
4102                 bit_bytes = ctl->unit;
4103                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false);
4104                 if (!ret) {
4105                         if (bit_off == offset) {
4106                                 ret = 1;
4107                                 goto out;
4108                         } else if (bit_off > offset &&
4109                                    offset + bytes > bit_off) {
4110                                 ret = 1;
4111                                 goto out;
4112                         }
4113                 }
4114
4115                 n = rb_prev(&info->offset_index);
4116                 while (n) {
4117                         tmp = rb_entry(n, struct btrfs_free_space,
4118                                        offset_index);
4119                         if (tmp->offset + tmp->bytes < offset)
4120                                 break;
4121                         if (offset + bytes < tmp->offset) {
4122                                 n = rb_prev(&tmp->offset_index);
4123                                 continue;
4124                         }
4125                         info = tmp;
4126                         goto have_info;
4127                 }
4128
4129                 n = rb_next(&info->offset_index);
4130                 while (n) {
4131                         tmp = rb_entry(n, struct btrfs_free_space,
4132                                        offset_index);
4133                         if (offset + bytes < tmp->offset)
4134                                 break;
4135                         if (tmp->offset + tmp->bytes < offset) {
4136                                 n = rb_next(&tmp->offset_index);
4137                                 continue;
4138                         }
4139                         info = tmp;
4140                         goto have_info;
4141                 }
4142
4143                 ret = 0;
4144                 goto out;
4145         }
4146
4147         if (info->offset == offset) {
4148                 ret = 1;
4149                 goto out;
4150         }
4151
4152         if (offset > info->offset && offset < info->offset + info->bytes)
4153                 ret = 1;
4154 out:
4155         spin_unlock(&ctl->tree_lock);
4156         return ret;
4157 }
4158 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */