Pileus Git - ~andy/linux/blob - fs/btrfs/free-space-cache.c

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