fs/btrfs/free-space-cache.c

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