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 "ctree.h" 24 #include "free-space-cache.h" 25 #include "transaction.h" 26 #include "disk-io.h" 27 #include "extent_io.h" 28 #include "inode-map.h" 29 30 #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8) 31 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024) 32 33 static int link_free_space(struct btrfs_free_space_ctl *ctl, 34 struct btrfs_free_space *info); 35 36 static struct inode *__lookup_free_space_inode(struct btrfs_root *root, 37 struct btrfs_path *path, 38 u64 offset) 39 { 40 struct btrfs_key key; 41 struct btrfs_key location; 42 struct btrfs_disk_key disk_key; 43 struct btrfs_free_space_header *header; 44 struct extent_buffer *leaf; 45 struct inode *inode = NULL; 46 int ret; 47 48 key.objectid = BTRFS_FREE_SPACE_OBJECTID; 49 key.offset = offset; 50 key.type = 0; 51 52 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 53 if (ret < 0) 54 return ERR_PTR(ret); 55 if (ret > 0) { 56 btrfs_release_path(path); 57 return ERR_PTR(-ENOENT); 58 } 59 60 leaf = path->nodes[0]; 61 header = btrfs_item_ptr(leaf, path->slots[0], 62 struct btrfs_free_space_header); 63 btrfs_free_space_key(leaf, header, &disk_key); 64 btrfs_disk_key_to_cpu(&location, &disk_key); 65 btrfs_release_path(path); 66 67 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL); 68 if (!inode) 69 return ERR_PTR(-ENOENT); 70 if (IS_ERR(inode)) 71 return inode; 72 if (is_bad_inode(inode)) { 73 iput(inode); 74 return ERR_PTR(-ENOENT); 75 } 76 77 inode->i_mapping->flags &= ~__GFP_FS; 78 79 return inode; 80 } 81 82 struct inode *lookup_free_space_inode(struct btrfs_root *root, 83 struct btrfs_block_group_cache 84 *block_group, struct btrfs_path *path) 85 { 86 struct inode *inode = NULL; 87 88 spin_lock(&block_group->lock); 89 if (block_group->inode) 90 inode = igrab(block_group->inode); 91 spin_unlock(&block_group->lock); 92 if (inode) 93 return inode; 94 95 inode = __lookup_free_space_inode(root, path, 96 block_group->key.objectid); 97 if (IS_ERR(inode)) 98 return inode; 99 100 spin_lock(&block_group->lock); 101 if (!btrfs_fs_closing(root->fs_info)) { 102 block_group->inode = igrab(inode); 103 block_group->iref = 1; 104 } 105 spin_unlock(&block_group->lock); 106 107 return inode; 108 } 109 110 int __create_free_space_inode(struct btrfs_root *root, 111 struct btrfs_trans_handle *trans, 112 struct btrfs_path *path, u64 ino, u64 offset) 113 { 114 struct btrfs_key key; 115 struct btrfs_disk_key disk_key; 116 struct btrfs_free_space_header *header; 117 struct btrfs_inode_item *inode_item; 118 struct extent_buffer *leaf; 119 int ret; 120 121 ret = btrfs_insert_empty_inode(trans, root, path, ino); 122 if (ret) 123 return ret; 124 125 leaf = path->nodes[0]; 126 inode_item = btrfs_item_ptr(leaf, path->slots[0], 127 struct btrfs_inode_item); 128 btrfs_item_key(leaf, &disk_key, path->slots[0]); 129 memset_extent_buffer(leaf, 0, (unsigned long)inode_item, 130 sizeof(*inode_item)); 131 btrfs_set_inode_generation(leaf, inode_item, trans->transid); 132 btrfs_set_inode_size(leaf, inode_item, 0); 133 btrfs_set_inode_nbytes(leaf, inode_item, 0); 134 btrfs_set_inode_uid(leaf, inode_item, 0); 135 btrfs_set_inode_gid(leaf, inode_item, 0); 136 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600); 137 btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS | 138 BTRFS_INODE_PREALLOC | BTRFS_INODE_NODATASUM); 139 btrfs_set_inode_nlink(leaf, inode_item, 1); 140 btrfs_set_inode_transid(leaf, inode_item, trans->transid); 141 btrfs_set_inode_block_group(leaf, inode_item, offset); 142 btrfs_mark_buffer_dirty(leaf); 143 btrfs_release_path(path); 144 145 key.objectid = BTRFS_FREE_SPACE_OBJECTID; 146 key.offset = offset; 147 key.type = 0; 148 149 ret = btrfs_insert_empty_item(trans, root, path, &key, 150 sizeof(struct btrfs_free_space_header)); 151 if (ret < 0) { 152 btrfs_release_path(path); 153 return ret; 154 } 155 leaf = path->nodes[0]; 156 header = btrfs_item_ptr(leaf, path->slots[0], 157 struct btrfs_free_space_header); 158 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header)); 159 btrfs_set_free_space_key(leaf, header, &disk_key); 160 btrfs_mark_buffer_dirty(leaf); 161 btrfs_release_path(path); 162 163 return 0; 164 } 165 166 int create_free_space_inode(struct btrfs_root *root, 167 struct btrfs_trans_handle *trans, 168 struct btrfs_block_group_cache *block_group, 169 struct btrfs_path *path) 170 { 171 int ret; 172 u64 ino; 173 174 ret = btrfs_find_free_objectid(root, &ino); 175 if (ret < 0) 176 return ret; 177 178 return __create_free_space_inode(root, trans, path, ino, 179 block_group->key.objectid); 180 } 181 182 int btrfs_truncate_free_space_cache(struct btrfs_root *root, 183 struct btrfs_trans_handle *trans, 184 struct btrfs_path *path, 185 struct inode *inode) 186 { 187 loff_t oldsize; 188 int ret = 0; 189 190 trans->block_rsv = root->orphan_block_rsv; 191 ret = btrfs_block_rsv_check(trans, root, 192 root->orphan_block_rsv, 193 0, 5); 194 if (ret) 195 return ret; 196 197 oldsize = i_size_read(inode); 198 btrfs_i_size_write(inode, 0); 199 truncate_pagecache(inode, oldsize, 0); 200 201 /* 202 * We don't need an orphan item because truncating the free space cache 203 * will never be split across transactions. 204 */ 205 ret = btrfs_truncate_inode_items(trans, root, inode, 206 0, BTRFS_EXTENT_DATA_KEY); 207 if (ret) { 208 WARN_ON(1); 209 return ret; 210 } 211 212 ret = btrfs_update_inode(trans, root, inode); 213 return ret; 214 } 215 216 static int readahead_cache(struct inode *inode) 217 { 218 struct file_ra_state *ra; 219 unsigned long last_index; 220 221 ra = kzalloc(sizeof(*ra), GFP_NOFS); 222 if (!ra) 223 return -ENOMEM; 224 225 file_ra_state_init(ra, inode->i_mapping); 226 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; 227 228 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index); 229 230 kfree(ra); 231 232 return 0; 233 } 234 235 int __load_free_space_cache(struct btrfs_root *root, struct inode *inode, 236 struct btrfs_free_space_ctl *ctl, 237 struct btrfs_path *path, u64 offset) 238 { 239 struct btrfs_free_space_header *header; 240 struct extent_buffer *leaf; 241 struct page *page; 242 u32 *checksums = NULL, *crc; 243 char *disk_crcs = NULL; 244 struct btrfs_key key; 245 struct list_head bitmaps; 246 u64 num_entries; 247 u64 num_bitmaps; 248 u64 generation; 249 u32 cur_crc = ~(u32)0; 250 pgoff_t index = 0; 251 unsigned long first_page_offset; 252 int num_checksums; 253 int ret = 0; 254 255 INIT_LIST_HEAD(&bitmaps); 256 257 /* Nothing in the space cache, goodbye */ 258 if (!i_size_read(inode)) 259 goto out; 260 261 key.objectid = BTRFS_FREE_SPACE_OBJECTID; 262 key.offset = offset; 263 key.type = 0; 264 265 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 266 if (ret < 0) 267 goto out; 268 else if (ret > 0) { 269 btrfs_release_path(path); 270 ret = 0; 271 goto out; 272 } 273 274 ret = -1; 275 276 leaf = path->nodes[0]; 277 header = btrfs_item_ptr(leaf, path->slots[0], 278 struct btrfs_free_space_header); 279 num_entries = btrfs_free_space_entries(leaf, header); 280 num_bitmaps = btrfs_free_space_bitmaps(leaf, header); 281 generation = btrfs_free_space_generation(leaf, header); 282 btrfs_release_path(path); 283 284 if (BTRFS_I(inode)->generation != generation) { 285 printk(KERN_ERR "btrfs: free space inode generation (%llu) did" 286 " not match free space cache generation (%llu)\n", 287 (unsigned long long)BTRFS_I(inode)->generation, 288 (unsigned long long)generation); 289 goto out; 290 } 291 292 if (!num_entries) 293 goto out; 294 295 /* Setup everything for doing checksumming */ 296 num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE; 297 checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS); 298 if (!checksums) 299 goto out; 300 first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64); 301 disk_crcs = kzalloc(first_page_offset, GFP_NOFS); 302 if (!disk_crcs) 303 goto out; 304 305 ret = readahead_cache(inode); 306 if (ret) 307 goto out; 308 309 while (1) { 310 struct btrfs_free_space_entry *entry; 311 struct btrfs_free_space *e; 312 void *addr; 313 unsigned long offset = 0; 314 unsigned long start_offset = 0; 315 int need_loop = 0; 316 317 if (!num_entries && !num_bitmaps) 318 break; 319 320 if (index == 0) { 321 start_offset = first_page_offset; 322 offset = start_offset; 323 } 324 325 page = grab_cache_page(inode->i_mapping, index); 326 if (!page) 327 goto free_cache; 328 329 if (!PageUptodate(page)) { 330 btrfs_readpage(NULL, page); 331 lock_page(page); 332 if (!PageUptodate(page)) { 333 unlock_page(page); 334 page_cache_release(page); 335 printk(KERN_ERR "btrfs: error reading free " 336 "space cache\n"); 337 goto free_cache; 338 } 339 } 340 addr = kmap(page); 341 342 if (index == 0) { 343 u64 *gen; 344 345 memcpy(disk_crcs, addr, first_page_offset); 346 gen = addr + (sizeof(u32) * num_checksums); 347 if (*gen != BTRFS_I(inode)->generation) { 348 printk(KERN_ERR "btrfs: space cache generation" 349 " (%llu) does not match inode (%llu)\n", 350 (unsigned long long)*gen, 351 (unsigned long long) 352 BTRFS_I(inode)->generation); 353 kunmap(page); 354 unlock_page(page); 355 page_cache_release(page); 356 goto free_cache; 357 } 358 crc = (u32 *)disk_crcs; 359 } 360 entry = addr + start_offset; 361 362 /* First lets check our crc before we do anything fun */ 363 cur_crc = ~(u32)0; 364 cur_crc = btrfs_csum_data(root, addr + start_offset, cur_crc, 365 PAGE_CACHE_SIZE - start_offset); 366 btrfs_csum_final(cur_crc, (char *)&cur_crc); 367 if (cur_crc != *crc) { 368 printk(KERN_ERR "btrfs: crc mismatch for page %lu\n", 369 index); 370 kunmap(page); 371 unlock_page(page); 372 page_cache_release(page); 373 goto free_cache; 374 } 375 crc++; 376 377 while (1) { 378 if (!num_entries) 379 break; 380 381 need_loop = 1; 382 e = kmem_cache_zalloc(btrfs_free_space_cachep, 383 GFP_NOFS); 384 if (!e) { 385 kunmap(page); 386 unlock_page(page); 387 page_cache_release(page); 388 goto free_cache; 389 } 390 391 e->offset = le64_to_cpu(entry->offset); 392 e->bytes = le64_to_cpu(entry->bytes); 393 if (!e->bytes) { 394 kunmap(page); 395 kmem_cache_free(btrfs_free_space_cachep, e); 396 unlock_page(page); 397 page_cache_release(page); 398 goto free_cache; 399 } 400 401 if (entry->type == BTRFS_FREE_SPACE_EXTENT) { 402 spin_lock(&ctl->tree_lock); 403 ret = link_free_space(ctl, e); 404 spin_unlock(&ctl->tree_lock); 405 if (ret) { 406 printk(KERN_ERR "Duplicate entries in " 407 "free space cache, dumping\n"); 408 kunmap(page); 409 unlock_page(page); 410 page_cache_release(page); 411 goto free_cache; 412 } 413 } else { 414 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS); 415 if (!e->bitmap) { 416 kunmap(page); 417 kmem_cache_free( 418 btrfs_free_space_cachep, e); 419 unlock_page(page); 420 page_cache_release(page); 421 goto free_cache; 422 } 423 spin_lock(&ctl->tree_lock); 424 ret = link_free_space(ctl, e); 425 ctl->total_bitmaps++; 426 ctl->op->recalc_thresholds(ctl); 427 spin_unlock(&ctl->tree_lock); 428 if (ret) { 429 printk(KERN_ERR "Duplicate entries in " 430 "free space cache, dumping\n"); 431 kunmap(page); 432 unlock_page(page); 433 page_cache_release(page); 434 goto free_cache; 435 } 436 list_add_tail(&e->list, &bitmaps); 437 } 438 439 num_entries--; 440 offset += sizeof(struct btrfs_free_space_entry); 441 if (offset + sizeof(struct btrfs_free_space_entry) >= 442 PAGE_CACHE_SIZE) 443 break; 444 entry++; 445 } 446 447 /* 448 * We read an entry out of this page, we need to move on to the 449 * next page. 450 */ 451 if (need_loop) { 452 kunmap(page); 453 goto next; 454 } 455 456 /* 457 * We add the bitmaps at the end of the entries in order that 458 * the bitmap entries are added to the cache. 459 */ 460 e = list_entry(bitmaps.next, struct btrfs_free_space, list); 461 list_del_init(&e->list); 462 memcpy(e->bitmap, addr, PAGE_CACHE_SIZE); 463 kunmap(page); 464 num_bitmaps--; 465 next: 466 unlock_page(page); 467 page_cache_release(page); 468 index++; 469 } 470 471 ret = 1; 472 out: 473 kfree(checksums); 474 kfree(disk_crcs); 475 return ret; 476 free_cache: 477 __btrfs_remove_free_space_cache(ctl); 478 goto out; 479 } 480 481 int load_free_space_cache(struct btrfs_fs_info *fs_info, 482 struct btrfs_block_group_cache *block_group) 483 { 484 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 485 struct btrfs_root *root = fs_info->tree_root; 486 struct inode *inode; 487 struct btrfs_path *path; 488 int ret; 489 bool matched; 490 u64 used = btrfs_block_group_used(&block_group->item); 491 492 /* 493 * If we're unmounting then just return, since this does a search on the 494 * normal root and not the commit root and we could deadlock. 495 */ 496 if (btrfs_fs_closing(fs_info)) 497 return 0; 498 499 /* 500 * If this block group has been marked to be cleared for one reason or 501 * another then we can't trust the on disk cache, so just return. 502 */ 503 spin_lock(&block_group->lock); 504 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) { 505 spin_unlock(&block_group->lock); 506 return 0; 507 } 508 spin_unlock(&block_group->lock); 509 510 path = btrfs_alloc_path(); 511 if (!path) 512 return 0; 513 514 inode = lookup_free_space_inode(root, block_group, path); 515 if (IS_ERR(inode)) { 516 btrfs_free_path(path); 517 return 0; 518 } 519 520 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl, 521 path, block_group->key.objectid); 522 btrfs_free_path(path); 523 if (ret <= 0) 524 goto out; 525 526 spin_lock(&ctl->tree_lock); 527 matched = (ctl->free_space == (block_group->key.offset - used - 528 block_group->bytes_super)); 529 spin_unlock(&ctl->tree_lock); 530 531 if (!matched) { 532 __btrfs_remove_free_space_cache(ctl); 533 printk(KERN_ERR "block group %llu has an wrong amount of free " 534 "space\n", block_group->key.objectid); 535 ret = -1; 536 } 537 out: 538 if (ret < 0) { 539 /* This cache is bogus, make sure it gets cleared */ 540 spin_lock(&block_group->lock); 541 block_group->disk_cache_state = BTRFS_DC_CLEAR; 542 spin_unlock(&block_group->lock); 543 ret = 0; 544 545 printk(KERN_ERR "btrfs: failed to load free space cache " 546 "for block group %llu\n", block_group->key.objectid); 547 } 548 549 iput(inode); 550 return ret; 551 } 552 553 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, 554 struct btrfs_free_space_ctl *ctl, 555 struct btrfs_block_group_cache *block_group, 556 struct btrfs_trans_handle *trans, 557 struct btrfs_path *path, u64 offset) 558 { 559 struct btrfs_free_space_header *header; 560 struct extent_buffer *leaf; 561 struct rb_node *node; 562 struct list_head *pos, *n; 563 struct page **pages; 564 struct page *page; 565 struct extent_state *cached_state = NULL; 566 struct btrfs_free_cluster *cluster = NULL; 567 struct extent_io_tree *unpin = NULL; 568 struct list_head bitmap_list; 569 struct btrfs_key key; 570 u64 start, end, len; 571 u64 bytes = 0; 572 u32 *crc, *checksums; 573 unsigned long first_page_offset; 574 int index = 0, num_pages = 0; 575 int entries = 0; 576 int bitmaps = 0; 577 int ret = -1; 578 bool next_page = false; 579 bool out_of_space = false; 580 581 INIT_LIST_HEAD(&bitmap_list); 582 583 node = rb_first(&ctl->free_space_offset); 584 if (!node) 585 return 0; 586 587 if (!i_size_read(inode)) 588 return -1; 589 590 num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> 591 PAGE_CACHE_SHIFT; 592 593 /* Since the first page has all of our checksums and our generation we 594 * need to calculate the offset into the page that we can start writing 595 * our entries. 596 */ 597 first_page_offset = (sizeof(u32) * num_pages) + sizeof(u64); 598 599 filemap_write_and_wait(inode->i_mapping); 600 btrfs_wait_ordered_range(inode, inode->i_size & 601 ~(root->sectorsize - 1), (u64)-1); 602 603 /* make sure we don't overflow that first page */ 604 if (first_page_offset + sizeof(struct btrfs_free_space_entry) >= PAGE_CACHE_SIZE) { 605 /* this is really the same as running out of space, where we also return 0 */ 606 printk(KERN_CRIT "Btrfs: free space cache was too big for the crc page\n"); 607 ret = 0; 608 goto out_update; 609 } 610 611 /* We need a checksum per page. */ 612 crc = checksums = kzalloc(sizeof(u32) * num_pages, GFP_NOFS); 613 if (!crc) 614 return -1; 615 616 pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS); 617 if (!pages) { 618 kfree(crc); 619 return -1; 620 } 621 622 /* Get the cluster for this block_group if it exists */ 623 if (block_group && !list_empty(&block_group->cluster_list)) 624 cluster = list_entry(block_group->cluster_list.next, 625 struct btrfs_free_cluster, 626 block_group_list); 627 628 /* 629 * We shouldn't have switched the pinned extents yet so this is the 630 * right one 631 */ 632 unpin = root->fs_info->pinned_extents; 633 634 /* 635 * Lock all pages first so we can lock the extent safely. 636 * 637 * NOTE: Because we hold the ref the entire time we're going to write to 638 * the page find_get_page should never fail, so we don't do a check 639 * after find_get_page at this point. Just putting this here so people 640 * know and don't freak out. 641 */ 642 while (index < num_pages) { 643 page = grab_cache_page(inode->i_mapping, index); 644 if (!page) { 645 int i; 646 647 for (i = 0; i < num_pages; i++) { 648 unlock_page(pages[i]); 649 page_cache_release(pages[i]); 650 } 651 goto out_free; 652 } 653 pages[index] = page; 654 index++; 655 } 656 657 index = 0; 658 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, 659 0, &cached_state, GFP_NOFS); 660 661 /* 662 * When searching for pinned extents, we need to start at our start 663 * offset. 664 */ 665 if (block_group) 666 start = block_group->key.objectid; 667 668 /* Write out the extent entries */ 669 do { 670 struct btrfs_free_space_entry *entry; 671 void *addr; 672 unsigned long offset = 0; 673 unsigned long start_offset = 0; 674 675 next_page = false; 676 677 if (index == 0) { 678 start_offset = first_page_offset; 679 offset = start_offset; 680 } 681 682 if (index >= num_pages) { 683 out_of_space = true; 684 break; 685 } 686 687 page = pages[index]; 688 689 addr = kmap(page); 690 entry = addr + start_offset; 691 692 memset(addr, 0, PAGE_CACHE_SIZE); 693 while (node && !next_page) { 694 struct btrfs_free_space *e; 695 696 e = rb_entry(node, struct btrfs_free_space, offset_index); 697 entries++; 698 699 entry->offset = cpu_to_le64(e->offset); 700 entry->bytes = cpu_to_le64(e->bytes); 701 if (e->bitmap) { 702 entry->type = BTRFS_FREE_SPACE_BITMAP; 703 list_add_tail(&e->list, &bitmap_list); 704 bitmaps++; 705 } else { 706 entry->type = BTRFS_FREE_SPACE_EXTENT; 707 } 708 node = rb_next(node); 709 if (!node && cluster) { 710 node = rb_first(&cluster->root); 711 cluster = NULL; 712 } 713 offset += sizeof(struct btrfs_free_space_entry); 714 if (offset + sizeof(struct btrfs_free_space_entry) >= 715 PAGE_CACHE_SIZE) 716 next_page = true; 717 entry++; 718 } 719 720 /* 721 * We want to add any pinned extents to our free space cache 722 * so we don't leak the space 723 */ 724 while (block_group && !next_page && 725 (start < block_group->key.objectid + 726 block_group->key.offset)) { 727 ret = find_first_extent_bit(unpin, start, &start, &end, 728 EXTENT_DIRTY); 729 if (ret) { 730 ret = 0; 731 break; 732 } 733 734 /* This pinned extent is out of our range */ 735 if (start >= block_group->key.objectid + 736 block_group->key.offset) 737 break; 738 739 len = block_group->key.objectid + 740 block_group->key.offset - start; 741 len = min(len, end + 1 - start); 742 743 entries++; 744 entry->offset = cpu_to_le64(start); 745 entry->bytes = cpu_to_le64(len); 746 entry->type = BTRFS_FREE_SPACE_EXTENT; 747 748 start = end + 1; 749 offset += sizeof(struct btrfs_free_space_entry); 750 if (offset + sizeof(struct btrfs_free_space_entry) >= 751 PAGE_CACHE_SIZE) 752 next_page = true; 753 entry++; 754 } 755 *crc = ~(u32)0; 756 *crc = btrfs_csum_data(root, addr + start_offset, *crc, 757 PAGE_CACHE_SIZE - start_offset); 758 kunmap(page); 759 760 btrfs_csum_final(*crc, (char *)crc); 761 crc++; 762 763 bytes += PAGE_CACHE_SIZE; 764 765 index++; 766 } while (node || next_page); 767 768 /* Write out the bitmaps */ 769 list_for_each_safe(pos, n, &bitmap_list) { 770 void *addr; 771 struct btrfs_free_space *entry = 772 list_entry(pos, struct btrfs_free_space, list); 773 774 if (index >= num_pages) { 775 out_of_space = true; 776 break; 777 } 778 page = pages[index]; 779 780 addr = kmap(page); 781 memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE); 782 *crc = ~(u32)0; 783 *crc = btrfs_csum_data(root, addr, *crc, PAGE_CACHE_SIZE); 784 kunmap(page); 785 btrfs_csum_final(*crc, (char *)crc); 786 crc++; 787 bytes += PAGE_CACHE_SIZE; 788 789 list_del_init(&entry->list); 790 index++; 791 } 792 793 if (out_of_space) { 794 btrfs_drop_pages(pages, num_pages); 795 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, 796 i_size_read(inode) - 1, &cached_state, 797 GFP_NOFS); 798 ret = 0; 799 goto out_free; 800 } 801 802 /* Zero out the rest of the pages just to make sure */ 803 while (index < num_pages) { 804 void *addr; 805 806 page = pages[index]; 807 addr = kmap(page); 808 memset(addr, 0, PAGE_CACHE_SIZE); 809 kunmap(page); 810 bytes += PAGE_CACHE_SIZE; 811 index++; 812 } 813 814 /* Write the checksums and trans id to the first page */ 815 { 816 void *addr; 817 u64 *gen; 818 819 page = pages[0]; 820 821 addr = kmap(page); 822 memcpy(addr, checksums, sizeof(u32) * num_pages); 823 gen = addr + (sizeof(u32) * num_pages); 824 *gen = trans->transid; 825 kunmap(page); 826 } 827 828 ret = btrfs_dirty_pages(root, inode, pages, num_pages, 0, 829 bytes, &cached_state); 830 btrfs_drop_pages(pages, num_pages); 831 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, 832 i_size_read(inode) - 1, &cached_state, GFP_NOFS); 833 834 if (ret) { 835 ret = 0; 836 goto out_free; 837 } 838 839 BTRFS_I(inode)->generation = trans->transid; 840 841 filemap_write_and_wait(inode->i_mapping); 842 843 key.objectid = BTRFS_FREE_SPACE_OBJECTID; 844 key.offset = offset; 845 key.type = 0; 846 847 ret = btrfs_search_slot(trans, root, &key, path, 1, 1); 848 if (ret < 0) { 849 ret = -1; 850 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1, 851 EXTENT_DIRTY | EXTENT_DELALLOC | 852 EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS); 853 goto out_free; 854 } 855 leaf = path->nodes[0]; 856 if (ret > 0) { 857 struct btrfs_key found_key; 858 BUG_ON(!path->slots[0]); 859 path->slots[0]--; 860 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 861 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID || 862 found_key.offset != offset) { 863 ret = -1; 864 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1, 865 EXTENT_DIRTY | EXTENT_DELALLOC | 866 EXTENT_DO_ACCOUNTING, 0, 0, NULL, 867 GFP_NOFS); 868 btrfs_release_path(path); 869 goto out_free; 870 } 871 } 872 header = btrfs_item_ptr(leaf, path->slots[0], 873 struct btrfs_free_space_header); 874 btrfs_set_free_space_entries(leaf, header, entries); 875 btrfs_set_free_space_bitmaps(leaf, header, bitmaps); 876 btrfs_set_free_space_generation(leaf, header, trans->transid); 877 btrfs_mark_buffer_dirty(leaf); 878 btrfs_release_path(path); 879 880 ret = 1; 881 882 out_free: 883 kfree(checksums); 884 kfree(pages); 885 886 out_update: 887 if (ret != 1) { 888 invalidate_inode_pages2_range(inode->i_mapping, 0, index); 889 BTRFS_I(inode)->generation = 0; 890 } 891 btrfs_update_inode(trans, root, inode); 892 return ret; 893 } 894 895 int btrfs_write_out_cache(struct btrfs_root *root, 896 struct btrfs_trans_handle *trans, 897 struct btrfs_block_group_cache *block_group, 898 struct btrfs_path *path) 899 { 900 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 901 struct inode *inode; 902 int ret = 0; 903 904 root = root->fs_info->tree_root; 905 906 spin_lock(&block_group->lock); 907 if (block_group->disk_cache_state < BTRFS_DC_SETUP) { 908 spin_unlock(&block_group->lock); 909 return 0; 910 } 911 spin_unlock(&block_group->lock); 912 913 inode = lookup_free_space_inode(root, block_group, path); 914 if (IS_ERR(inode)) 915 return 0; 916 917 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans, 918 path, block_group->key.objectid); 919 if (ret < 0) { 920 spin_lock(&block_group->lock); 921 block_group->disk_cache_state = BTRFS_DC_ERROR; 922 spin_unlock(&block_group->lock); 923 ret = 0; 924 925 printk(KERN_ERR "btrfs: failed to write free space cace " 926 "for block group %llu\n", block_group->key.objectid); 927 } 928 929 iput(inode); 930 return ret; 931 } 932 933 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit, 934 u64 offset) 935 { 936 BUG_ON(offset < bitmap_start); 937 offset -= bitmap_start; 938 return (unsigned long)(div_u64(offset, unit)); 939 } 940 941 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit) 942 { 943 return (unsigned long)(div_u64(bytes, unit)); 944 } 945 946 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl, 947 u64 offset) 948 { 949 u64 bitmap_start; 950 u64 bytes_per_bitmap; 951 952 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit; 953 bitmap_start = offset - ctl->start; 954 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap); 955 bitmap_start *= bytes_per_bitmap; 956 bitmap_start += ctl->start; 957 958 return bitmap_start; 959 } 960 961 static int tree_insert_offset(struct rb_root *root, u64 offset, 962 struct rb_node *node, int bitmap) 963 { 964 struct rb_node **p = &root->rb_node; 965 struct rb_node *parent = NULL; 966 struct btrfs_free_space *info; 967 968 while (*p) { 969 parent = *p; 970 info = rb_entry(parent, struct btrfs_free_space, offset_index); 971 972 if (offset < info->offset) { 973 p = &(*p)->rb_left; 974 } else if (offset > info->offset) { 975 p = &(*p)->rb_right; 976 } else { 977 /* 978 * we could have a bitmap entry and an extent entry 979 * share the same offset. If this is the case, we want 980 * the extent entry to always be found first if we do a 981 * linear search through the tree, since we want to have 982 * the quickest allocation time, and allocating from an 983 * extent is faster than allocating from a bitmap. So 984 * if we're inserting a bitmap and we find an entry at 985 * this offset, we want to go right, or after this entry 986 * logically. If we are inserting an extent and we've 987 * found a bitmap, we want to go left, or before 988 * logically. 989 */ 990 if (bitmap) { 991 if (info->bitmap) { 992 WARN_ON_ONCE(1); 993 return -EEXIST; 994 } 995 p = &(*p)->rb_right; 996 } else { 997 if (!info->bitmap) { 998 WARN_ON_ONCE(1); 999 return -EEXIST; 1000 } 1001 p = &(*p)->rb_left; 1002 } 1003 } 1004 } 1005 1006 rb_link_node(node, parent, p); 1007 rb_insert_color(node, root); 1008 1009 return 0; 1010 } 1011 1012 /* 1013 * searches the tree for the given offset. 1014 * 1015 * fuzzy - If this is set, then we are trying to make an allocation, and we just 1016 * want a section that has at least bytes size and comes at or after the given 1017 * offset. 1018 */ 1019 static struct btrfs_free_space * 1020 tree_search_offset(struct btrfs_free_space_ctl *ctl, 1021 u64 offset, int bitmap_only, int fuzzy) 1022 { 1023 struct rb_node *n = ctl->free_space_offset.rb_node; 1024 struct btrfs_free_space *entry, *prev = NULL; 1025 1026 /* find entry that is closest to the 'offset' */ 1027 while (1) { 1028 if (!n) { 1029 entry = NULL; 1030 break; 1031 } 1032 1033 entry = rb_entry(n, struct btrfs_free_space, offset_index); 1034 prev = entry; 1035 1036 if (offset < entry->offset) 1037 n = n->rb_left; 1038 else if (offset > entry->offset) 1039 n = n->rb_right; 1040 else 1041 break; 1042 } 1043 1044 if (bitmap_only) { 1045 if (!entry) 1046 return NULL; 1047 if (entry->bitmap) 1048 return entry; 1049 1050 /* 1051 * bitmap entry and extent entry may share same offset, 1052 * in that case, bitmap entry comes after extent entry. 1053 */ 1054 n = rb_next(n); 1055 if (!n) 1056 return NULL; 1057 entry = rb_entry(n, struct btrfs_free_space, offset_index); 1058 if (entry->offset != offset) 1059 return NULL; 1060 1061 WARN_ON(!entry->bitmap); 1062 return entry; 1063 } else if (entry) { 1064 if (entry->bitmap) { 1065 /* 1066 * if previous extent entry covers the offset, 1067 * we should return it instead of the bitmap entry 1068 */ 1069 n = &entry->offset_index; 1070 while (1) { 1071 n = rb_prev(n); 1072 if (!n) 1073 break; 1074 prev = rb_entry(n, struct btrfs_free_space, 1075 offset_index); 1076 if (!prev->bitmap) { 1077 if (prev->offset + prev->bytes > offset) 1078 entry = prev; 1079 break; 1080 } 1081 } 1082 } 1083 return entry; 1084 } 1085 1086 if (!prev) 1087 return NULL; 1088 1089 /* find last entry before the 'offset' */ 1090 entry = prev; 1091 if (entry->offset > offset) { 1092 n = rb_prev(&entry->offset_index); 1093 if (n) { 1094 entry = rb_entry(n, struct btrfs_free_space, 1095 offset_index); 1096 BUG_ON(entry->offset > offset); 1097 } else { 1098 if (fuzzy) 1099 return entry; 1100 else 1101 return NULL; 1102 } 1103 } 1104 1105 if (entry->bitmap) { 1106 n = &entry->offset_index; 1107 while (1) { 1108 n = rb_prev(n); 1109 if (!n) 1110 break; 1111 prev = rb_entry(n, struct btrfs_free_space, 1112 offset_index); 1113 if (!prev->bitmap) { 1114 if (prev->offset + prev->bytes > offset) 1115 return prev; 1116 break; 1117 } 1118 } 1119 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset) 1120 return entry; 1121 } else if (entry->offset + entry->bytes > offset) 1122 return entry; 1123 1124 if (!fuzzy) 1125 return NULL; 1126 1127 while (1) { 1128 if (entry->bitmap) { 1129 if (entry->offset + BITS_PER_BITMAP * 1130 ctl->unit > offset) 1131 break; 1132 } else { 1133 if (entry->offset + entry->bytes > offset) 1134 break; 1135 } 1136 1137 n = rb_next(&entry->offset_index); 1138 if (!n) 1139 return NULL; 1140 entry = rb_entry(n, struct btrfs_free_space, offset_index); 1141 } 1142 return entry; 1143 } 1144 1145 static inline void 1146 __unlink_free_space(struct btrfs_free_space_ctl *ctl, 1147 struct btrfs_free_space *info) 1148 { 1149 rb_erase(&info->offset_index, &ctl->free_space_offset); 1150 ctl->free_extents--; 1151 } 1152 1153 static void unlink_free_space(struct btrfs_free_space_ctl *ctl, 1154 struct btrfs_free_space *info) 1155 { 1156 __unlink_free_space(ctl, info); 1157 ctl->free_space -= info->bytes; 1158 } 1159 1160 static int link_free_space(struct btrfs_free_space_ctl *ctl, 1161 struct btrfs_free_space *info) 1162 { 1163 int ret = 0; 1164 1165 BUG_ON(!info->bitmap && !info->bytes); 1166 ret = tree_insert_offset(&ctl->free_space_offset, info->offset, 1167 &info->offset_index, (info->bitmap != NULL)); 1168 if (ret) 1169 return ret; 1170 1171 ctl->free_space += info->bytes; 1172 ctl->free_extents++; 1173 return ret; 1174 } 1175 1176 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) 1177 { 1178 struct btrfs_block_group_cache *block_group = ctl->private; 1179 u64 max_bytes; 1180 u64 bitmap_bytes; 1181 u64 extent_bytes; 1182 u64 size = block_group->key.offset; 1183 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize; 1184 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg); 1185 1186 BUG_ON(ctl->total_bitmaps > max_bitmaps); 1187 1188 /* 1189 * The goal is to keep the total amount of memory used per 1gb of space 1190 * at or below 32k, so we need to adjust how much memory we allow to be 1191 * used by extent based free space tracking 1192 */ 1193 if (size < 1024 * 1024 * 1024) 1194 max_bytes = MAX_CACHE_BYTES_PER_GIG; 1195 else 1196 max_bytes = MAX_CACHE_BYTES_PER_GIG * 1197 div64_u64(size, 1024 * 1024 * 1024); 1198 1199 /* 1200 * we want to account for 1 more bitmap than what we have so we can make 1201 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as 1202 * we add more bitmaps. 1203 */ 1204 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE; 1205 1206 if (bitmap_bytes >= max_bytes) { 1207 ctl->extents_thresh = 0; 1208 return; 1209 } 1210 1211 /* 1212 * we want the extent entry threshold to always be at most 1/2 the maxw 1213 * bytes we can have, or whatever is less than that. 1214 */ 1215 extent_bytes = max_bytes - bitmap_bytes; 1216 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2)); 1217 1218 ctl->extents_thresh = 1219 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space))); 1220 } 1221 1222 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl, 1223 struct btrfs_free_space *info, u64 offset, 1224 u64 bytes) 1225 { 1226 unsigned long start, count; 1227 1228 start = offset_to_bit(info->offset, ctl->unit, offset); 1229 count = bytes_to_bits(bytes, ctl->unit); 1230 BUG_ON(start + count > BITS_PER_BITMAP); 1231 1232 bitmap_clear(info->bitmap, start, count); 1233 1234 info->bytes -= bytes; 1235 ctl->free_space -= bytes; 1236 } 1237 1238 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl, 1239 struct btrfs_free_space *info, u64 offset, 1240 u64 bytes) 1241 { 1242 unsigned long start, count; 1243 1244 start = offset_to_bit(info->offset, ctl->unit, offset); 1245 count = bytes_to_bits(bytes, ctl->unit); 1246 BUG_ON(start + count > BITS_PER_BITMAP); 1247 1248 bitmap_set(info->bitmap, start, count); 1249 1250 info->bytes += bytes; 1251 ctl->free_space += bytes; 1252 } 1253 1254 static int search_bitmap(struct btrfs_free_space_ctl *ctl, 1255 struct btrfs_free_space *bitmap_info, u64 *offset, 1256 u64 *bytes) 1257 { 1258 unsigned long found_bits = 0; 1259 unsigned long bits, i; 1260 unsigned long next_zero; 1261 1262 i = offset_to_bit(bitmap_info->offset, ctl->unit, 1263 max_t(u64, *offset, bitmap_info->offset)); 1264 bits = bytes_to_bits(*bytes, ctl->unit); 1265 1266 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i); 1267 i < BITS_PER_BITMAP; 1268 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) { 1269 next_zero = find_next_zero_bit(bitmap_info->bitmap, 1270 BITS_PER_BITMAP, i); 1271 if ((next_zero - i) >= bits) { 1272 found_bits = next_zero - i; 1273 break; 1274 } 1275 i = next_zero; 1276 } 1277 1278 if (found_bits) { 1279 *offset = (u64)(i * ctl->unit) + bitmap_info->offset; 1280 *bytes = (u64)(found_bits) * ctl->unit; 1281 return 0; 1282 } 1283 1284 return -1; 1285 } 1286 1287 static struct btrfs_free_space * 1288 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes) 1289 { 1290 struct btrfs_free_space *entry; 1291 struct rb_node *node; 1292 int ret; 1293 1294 if (!ctl->free_space_offset.rb_node) 1295 return NULL; 1296 1297 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1); 1298 if (!entry) 1299 return NULL; 1300 1301 for (node = &entry->offset_index; node; node = rb_next(node)) { 1302 entry = rb_entry(node, struct btrfs_free_space, offset_index); 1303 if (entry->bytes < *bytes) 1304 continue; 1305 1306 if (entry->bitmap) { 1307 ret = search_bitmap(ctl, entry, offset, bytes); 1308 if (!ret) 1309 return entry; 1310 continue; 1311 } 1312 1313 *offset = entry->offset; 1314 *bytes = entry->bytes; 1315 return entry; 1316 } 1317 1318 return NULL; 1319 } 1320 1321 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl, 1322 struct btrfs_free_space *info, u64 offset) 1323 { 1324 info->offset = offset_to_bitmap(ctl, offset); 1325 info->bytes = 0; 1326 link_free_space(ctl, info); 1327 ctl->total_bitmaps++; 1328 1329 ctl->op->recalc_thresholds(ctl); 1330 } 1331 1332 static void free_bitmap(struct btrfs_free_space_ctl *ctl, 1333 struct btrfs_free_space *bitmap_info) 1334 { 1335 unlink_free_space(ctl, bitmap_info); 1336 kfree(bitmap_info->bitmap); 1337 kmem_cache_free(btrfs_free_space_cachep, bitmap_info); 1338 ctl->total_bitmaps--; 1339 ctl->op->recalc_thresholds(ctl); 1340 } 1341 1342 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl, 1343 struct btrfs_free_space *bitmap_info, 1344 u64 *offset, u64 *bytes) 1345 { 1346 u64 end; 1347 u64 search_start, search_bytes; 1348 int ret; 1349 1350 again: 1351 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1; 1352 1353 /* 1354 * XXX - this can go away after a few releases. 1355 * 1356 * since the only user of btrfs_remove_free_space is the tree logging 1357 * stuff, and the only way to test that is under crash conditions, we 1358 * want to have this debug stuff here just in case somethings not 1359 * working. Search the bitmap for the space we are trying to use to 1360 * make sure its actually there. If its not there then we need to stop 1361 * because something has gone wrong. 1362 */ 1363 search_start = *offset; 1364 search_bytes = *bytes; 1365 search_bytes = min(search_bytes, end - search_start + 1); 1366 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes); 1367 BUG_ON(ret < 0 || search_start != *offset); 1368 1369 if (*offset > bitmap_info->offset && *offset + *bytes > end) { 1370 bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1); 1371 *bytes -= end - *offset + 1; 1372 *offset = end + 1; 1373 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) { 1374 bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes); 1375 *bytes = 0; 1376 } 1377 1378 if (*bytes) { 1379 struct rb_node *next = rb_next(&bitmap_info->offset_index); 1380 if (!bitmap_info->bytes) 1381 free_bitmap(ctl, bitmap_info); 1382 1383 /* 1384 * no entry after this bitmap, but we still have bytes to 1385 * remove, so something has gone wrong. 1386 */ 1387 if (!next) 1388 return -EINVAL; 1389 1390 bitmap_info = rb_entry(next, struct btrfs_free_space, 1391 offset_index); 1392 1393 /* 1394 * if the next entry isn't a bitmap we need to return to let the 1395 * extent stuff do its work. 1396 */ 1397 if (!bitmap_info->bitmap) 1398 return -EAGAIN; 1399 1400 /* 1401 * Ok the next item is a bitmap, but it may not actually hold 1402 * the information for the rest of this free space stuff, so 1403 * look for it, and if we don't find it return so we can try 1404 * everything over again. 1405 */ 1406 search_start = *offset; 1407 search_bytes = *bytes; 1408 ret = search_bitmap(ctl, bitmap_info, &search_start, 1409 &search_bytes); 1410 if (ret < 0 || search_start != *offset) 1411 return -EAGAIN; 1412 1413 goto again; 1414 } else if (!bitmap_info->bytes) 1415 free_bitmap(ctl, bitmap_info); 1416 1417 return 0; 1418 } 1419 1420 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl, 1421 struct btrfs_free_space *info, u64 offset, 1422 u64 bytes) 1423 { 1424 u64 bytes_to_set = 0; 1425 u64 end; 1426 1427 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit); 1428 1429 bytes_to_set = min(end - offset, bytes); 1430 1431 bitmap_set_bits(ctl, info, offset, bytes_to_set); 1432 1433 return bytes_to_set; 1434 1435 } 1436 1437 static bool use_bitmap(struct btrfs_free_space_ctl *ctl, 1438 struct btrfs_free_space *info) 1439 { 1440 struct btrfs_block_group_cache *block_group = ctl->private; 1441 1442 /* 1443 * If we are below the extents threshold then we can add this as an 1444 * extent, and don't have to deal with the bitmap 1445 */ 1446 if (ctl->free_extents < ctl->extents_thresh) { 1447 /* 1448 * If this block group has some small extents we don't want to 1449 * use up all of our free slots in the cache with them, we want 1450 * to reserve them to larger extents, however if we have plent 1451 * of cache left then go ahead an dadd them, no sense in adding 1452 * the overhead of a bitmap if we don't have to. 1453 */ 1454 if (info->bytes <= block_group->sectorsize * 4) { 1455 if (ctl->free_extents * 2 <= ctl->extents_thresh) 1456 return false; 1457 } else { 1458 return false; 1459 } 1460 } 1461 1462 /* 1463 * some block groups are so tiny they can't be enveloped by a bitmap, so 1464 * don't even bother to create a bitmap for this 1465 */ 1466 if (BITS_PER_BITMAP * block_group->sectorsize > 1467 block_group->key.offset) 1468 return false; 1469 1470 return true; 1471 } 1472 1473 static struct btrfs_free_space_op free_space_op = { 1474 .recalc_thresholds = recalculate_thresholds, 1475 .use_bitmap = use_bitmap, 1476 }; 1477 1478 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl, 1479 struct btrfs_free_space *info) 1480 { 1481 struct btrfs_free_space *bitmap_info; 1482 struct btrfs_block_group_cache *block_group = NULL; 1483 int added = 0; 1484 u64 bytes, offset, bytes_added; 1485 int ret; 1486 1487 bytes = info->bytes; 1488 offset = info->offset; 1489 1490 if (!ctl->op->use_bitmap(ctl, info)) 1491 return 0; 1492 1493 if (ctl->op == &free_space_op) 1494 block_group = ctl->private; 1495 again: 1496 /* 1497 * Since we link bitmaps right into the cluster we need to see if we 1498 * have a cluster here, and if so and it has our bitmap we need to add 1499 * the free space to that bitmap. 1500 */ 1501 if (block_group && !list_empty(&block_group->cluster_list)) { 1502 struct btrfs_free_cluster *cluster; 1503 struct rb_node *node; 1504 struct btrfs_free_space *entry; 1505 1506 cluster = list_entry(block_group->cluster_list.next, 1507 struct btrfs_free_cluster, 1508 block_group_list); 1509 spin_lock(&cluster->lock); 1510 node = rb_first(&cluster->root); 1511 if (!node) { 1512 spin_unlock(&cluster->lock); 1513 goto no_cluster_bitmap; 1514 } 1515 1516 entry = rb_entry(node, struct btrfs_free_space, offset_index); 1517 if (!entry->bitmap) { 1518 spin_unlock(&cluster->lock); 1519 goto no_cluster_bitmap; 1520 } 1521 1522 if (entry->offset == offset_to_bitmap(ctl, offset)) { 1523 bytes_added = add_bytes_to_bitmap(ctl, entry, 1524 offset, bytes); 1525 bytes -= bytes_added; 1526 offset += bytes_added; 1527 } 1528 spin_unlock(&cluster->lock); 1529 if (!bytes) { 1530 ret = 1; 1531 goto out; 1532 } 1533 } 1534 1535 no_cluster_bitmap: 1536 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 1537 1, 0); 1538 if (!bitmap_info) { 1539 BUG_ON(added); 1540 goto new_bitmap; 1541 } 1542 1543 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes); 1544 bytes -= bytes_added; 1545 offset += bytes_added; 1546 added = 0; 1547 1548 if (!bytes) { 1549 ret = 1; 1550 goto out; 1551 } else 1552 goto again; 1553 1554 new_bitmap: 1555 if (info && info->bitmap) { 1556 add_new_bitmap(ctl, info, offset); 1557 added = 1; 1558 info = NULL; 1559 goto again; 1560 } else { 1561 spin_unlock(&ctl->tree_lock); 1562 1563 /* no pre-allocated info, allocate a new one */ 1564 if (!info) { 1565 info = kmem_cache_zalloc(btrfs_free_space_cachep, 1566 GFP_NOFS); 1567 if (!info) { 1568 spin_lock(&ctl->tree_lock); 1569 ret = -ENOMEM; 1570 goto out; 1571 } 1572 } 1573 1574 /* allocate the bitmap */ 1575 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS); 1576 spin_lock(&ctl->tree_lock); 1577 if (!info->bitmap) { 1578 ret = -ENOMEM; 1579 goto out; 1580 } 1581 goto again; 1582 } 1583 1584 out: 1585 if (info) { 1586 if (info->bitmap) 1587 kfree(info->bitmap); 1588 kmem_cache_free(btrfs_free_space_cachep, info); 1589 } 1590 1591 return ret; 1592 } 1593 1594 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl, 1595 struct btrfs_free_space *info, bool update_stat) 1596 { 1597 struct btrfs_free_space *left_info; 1598 struct btrfs_free_space *right_info; 1599 bool merged = false; 1600 u64 offset = info->offset; 1601 u64 bytes = info->bytes; 1602 1603 /* 1604 * first we want to see if there is free space adjacent to the range we 1605 * are adding, if there is remove that struct and add a new one to 1606 * cover the entire range 1607 */ 1608 right_info = tree_search_offset(ctl, offset + bytes, 0, 0); 1609 if (right_info && rb_prev(&right_info->offset_index)) 1610 left_info = rb_entry(rb_prev(&right_info->offset_index), 1611 struct btrfs_free_space, offset_index); 1612 else 1613 left_info = tree_search_offset(ctl, offset - 1, 0, 0); 1614 1615 if (right_info && !right_info->bitmap) { 1616 if (update_stat) 1617 unlink_free_space(ctl, right_info); 1618 else 1619 __unlink_free_space(ctl, right_info); 1620 info->bytes += right_info->bytes; 1621 kmem_cache_free(btrfs_free_space_cachep, right_info); 1622 merged = true; 1623 } 1624 1625 if (left_info && !left_info->bitmap && 1626 left_info->offset + left_info->bytes == offset) { 1627 if (update_stat) 1628 unlink_free_space(ctl, left_info); 1629 else 1630 __unlink_free_space(ctl, left_info); 1631 info->offset = left_info->offset; 1632 info->bytes += left_info->bytes; 1633 kmem_cache_free(btrfs_free_space_cachep, left_info); 1634 merged = true; 1635 } 1636 1637 return merged; 1638 } 1639 1640 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl, 1641 u64 offset, u64 bytes) 1642 { 1643 struct btrfs_free_space *info; 1644 int ret = 0; 1645 1646 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS); 1647 if (!info) 1648 return -ENOMEM; 1649 1650 info->offset = offset; 1651 info->bytes = bytes; 1652 1653 spin_lock(&ctl->tree_lock); 1654 1655 if (try_merge_free_space(ctl, info, true)) 1656 goto link; 1657 1658 /* 1659 * There was no extent directly to the left or right of this new 1660 * extent then we know we're going to have to allocate a new extent, so 1661 * before we do that see if we need to drop this into a bitmap 1662 */ 1663 ret = insert_into_bitmap(ctl, info); 1664 if (ret < 0) { 1665 goto out; 1666 } else if (ret) { 1667 ret = 0; 1668 goto out; 1669 } 1670 link: 1671 ret = link_free_space(ctl, info); 1672 if (ret) 1673 kmem_cache_free(btrfs_free_space_cachep, info); 1674 out: 1675 spin_unlock(&ctl->tree_lock); 1676 1677 if (ret) { 1678 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret); 1679 BUG_ON(ret == -EEXIST); 1680 } 1681 1682 return ret; 1683 } 1684 1685 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, 1686 u64 offset, u64 bytes) 1687 { 1688 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 1689 struct btrfs_free_space *info; 1690 struct btrfs_free_space *next_info = NULL; 1691 int ret = 0; 1692 1693 spin_lock(&ctl->tree_lock); 1694 1695 again: 1696 info = tree_search_offset(ctl, offset, 0, 0); 1697 if (!info) { 1698 /* 1699 * oops didn't find an extent that matched the space we wanted 1700 * to remove, look for a bitmap instead 1701 */ 1702 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 1703 1, 0); 1704 if (!info) { 1705 WARN_ON(1); 1706 goto out_lock; 1707 } 1708 } 1709 1710 if (info->bytes < bytes && rb_next(&info->offset_index)) { 1711 u64 end; 1712 next_info = rb_entry(rb_next(&info->offset_index), 1713 struct btrfs_free_space, 1714 offset_index); 1715 1716 if (next_info->bitmap) 1717 end = next_info->offset + 1718 BITS_PER_BITMAP * ctl->unit - 1; 1719 else 1720 end = next_info->offset + next_info->bytes; 1721 1722 if (next_info->bytes < bytes || 1723 next_info->offset > offset || offset > end) { 1724 printk(KERN_CRIT "Found free space at %llu, size %llu," 1725 " trying to use %llu\n", 1726 (unsigned long long)info->offset, 1727 (unsigned long long)info->bytes, 1728 (unsigned long long)bytes); 1729 WARN_ON(1); 1730 ret = -EINVAL; 1731 goto out_lock; 1732 } 1733 1734 info = next_info; 1735 } 1736 1737 if (info->bytes == bytes) { 1738 unlink_free_space(ctl, info); 1739 if (info->bitmap) { 1740 kfree(info->bitmap); 1741 ctl->total_bitmaps--; 1742 } 1743 kmem_cache_free(btrfs_free_space_cachep, info); 1744 goto out_lock; 1745 } 1746 1747 if (!info->bitmap && info->offset == offset) { 1748 unlink_free_space(ctl, info); 1749 info->offset += bytes; 1750 info->bytes -= bytes; 1751 link_free_space(ctl, info); 1752 goto out_lock; 1753 } 1754 1755 if (!info->bitmap && info->offset <= offset && 1756 info->offset + info->bytes >= offset + bytes) { 1757 u64 old_start = info->offset; 1758 /* 1759 * we're freeing space in the middle of the info, 1760 * this can happen during tree log replay 1761 * 1762 * first unlink the old info and then 1763 * insert it again after the hole we're creating 1764 */ 1765 unlink_free_space(ctl, info); 1766 if (offset + bytes < info->offset + info->bytes) { 1767 u64 old_end = info->offset + info->bytes; 1768 1769 info->offset = offset + bytes; 1770 info->bytes = old_end - info->offset; 1771 ret = link_free_space(ctl, info); 1772 WARN_ON(ret); 1773 if (ret) 1774 goto out_lock; 1775 } else { 1776 /* the hole we're creating ends at the end 1777 * of the info struct, just free the info 1778 */ 1779 kmem_cache_free(btrfs_free_space_cachep, info); 1780 } 1781 spin_unlock(&ctl->tree_lock); 1782 1783 /* step two, insert a new info struct to cover 1784 * anything before the hole 1785 */ 1786 ret = btrfs_add_free_space(block_group, old_start, 1787 offset - old_start); 1788 WARN_ON(ret); 1789 goto out; 1790 } 1791 1792 ret = remove_from_bitmap(ctl, info, &offset, &bytes); 1793 if (ret == -EAGAIN) 1794 goto again; 1795 BUG_ON(ret); 1796 out_lock: 1797 spin_unlock(&ctl->tree_lock); 1798 out: 1799 return ret; 1800 } 1801 1802 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, 1803 u64 bytes) 1804 { 1805 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 1806 struct btrfs_free_space *info; 1807 struct rb_node *n; 1808 int count = 0; 1809 1810 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) { 1811 info = rb_entry(n, struct btrfs_free_space, offset_index); 1812 if (info->bytes >= bytes) 1813 count++; 1814 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n", 1815 (unsigned long long)info->offset, 1816 (unsigned long long)info->bytes, 1817 (info->bitmap) ? "yes" : "no"); 1818 } 1819 printk(KERN_INFO "block group has cluster?: %s\n", 1820 list_empty(&block_group->cluster_list) ? "no" : "yes"); 1821 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is" 1822 "\n", count); 1823 } 1824 1825 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group) 1826 { 1827 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 1828 1829 spin_lock_init(&ctl->tree_lock); 1830 ctl->unit = block_group->sectorsize; 1831 ctl->start = block_group->key.objectid; 1832 ctl->private = block_group; 1833 ctl->op = &free_space_op; 1834 1835 /* 1836 * we only want to have 32k of ram per block group for keeping 1837 * track of free space, and if we pass 1/2 of that we want to 1838 * start converting things over to using bitmaps 1839 */ 1840 ctl->extents_thresh = ((1024 * 32) / 2) / 1841 sizeof(struct btrfs_free_space); 1842 } 1843 1844 /* 1845 * for a given cluster, put all of its extents back into the free 1846 * space cache. If the block group passed doesn't match the block group 1847 * pointed to by the cluster, someone else raced in and freed the 1848 * cluster already. In that case, we just return without changing anything 1849 */ 1850 static int 1851 __btrfs_return_cluster_to_free_space( 1852 struct btrfs_block_group_cache *block_group, 1853 struct btrfs_free_cluster *cluster) 1854 { 1855 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 1856 struct btrfs_free_space *entry; 1857 struct rb_node *node; 1858 1859 spin_lock(&cluster->lock); 1860 if (cluster->block_group != block_group) 1861 goto out; 1862 1863 cluster->block_group = NULL; 1864 cluster->window_start = 0; 1865 list_del_init(&cluster->block_group_list); 1866 1867 node = rb_first(&cluster->root); 1868 while (node) { 1869 bool bitmap; 1870 1871 entry = rb_entry(node, struct btrfs_free_space, offset_index); 1872 node = rb_next(&entry->offset_index); 1873 rb_erase(&entry->offset_index, &cluster->root); 1874 1875 bitmap = (entry->bitmap != NULL); 1876 if (!bitmap) 1877 try_merge_free_space(ctl, entry, false); 1878 tree_insert_offset(&ctl->free_space_offset, 1879 entry->offset, &entry->offset_index, bitmap); 1880 } 1881 cluster->root = RB_ROOT; 1882 1883 out: 1884 spin_unlock(&cluster->lock); 1885 btrfs_put_block_group(block_group); 1886 return 0; 1887 } 1888 1889 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl) 1890 { 1891 struct btrfs_free_space *info; 1892 struct rb_node *node; 1893 1894 while ((node = rb_last(&ctl->free_space_offset)) != NULL) { 1895 info = rb_entry(node, struct btrfs_free_space, offset_index); 1896 if (!info->bitmap) { 1897 unlink_free_space(ctl, info); 1898 kmem_cache_free(btrfs_free_space_cachep, info); 1899 } else { 1900 free_bitmap(ctl, info); 1901 } 1902 if (need_resched()) { 1903 spin_unlock(&ctl->tree_lock); 1904 cond_resched(); 1905 spin_lock(&ctl->tree_lock); 1906 } 1907 } 1908 } 1909 1910 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl) 1911 { 1912 spin_lock(&ctl->tree_lock); 1913 __btrfs_remove_free_space_cache_locked(ctl); 1914 spin_unlock(&ctl->tree_lock); 1915 } 1916 1917 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group) 1918 { 1919 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 1920 struct btrfs_free_cluster *cluster; 1921 struct list_head *head; 1922 1923 spin_lock(&ctl->tree_lock); 1924 while ((head = block_group->cluster_list.next) != 1925 &block_group->cluster_list) { 1926 cluster = list_entry(head, struct btrfs_free_cluster, 1927 block_group_list); 1928 1929 WARN_ON(cluster->block_group != block_group); 1930 __btrfs_return_cluster_to_free_space(block_group, cluster); 1931 if (need_resched()) { 1932 spin_unlock(&ctl->tree_lock); 1933 cond_resched(); 1934 spin_lock(&ctl->tree_lock); 1935 } 1936 } 1937 __btrfs_remove_free_space_cache_locked(ctl); 1938 spin_unlock(&ctl->tree_lock); 1939 1940 } 1941 1942 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, 1943 u64 offset, u64 bytes, u64 empty_size) 1944 { 1945 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 1946 struct btrfs_free_space *entry = NULL; 1947 u64 bytes_search = bytes + empty_size; 1948 u64 ret = 0; 1949 1950 spin_lock(&ctl->tree_lock); 1951 entry = find_free_space(ctl, &offset, &bytes_search); 1952 if (!entry) 1953 goto out; 1954 1955 ret = offset; 1956 if (entry->bitmap) { 1957 bitmap_clear_bits(ctl, entry, offset, bytes); 1958 if (!entry->bytes) 1959 free_bitmap(ctl, entry); 1960 } else { 1961 unlink_free_space(ctl, entry); 1962 entry->offset += bytes; 1963 entry->bytes -= bytes; 1964 if (!entry->bytes) 1965 kmem_cache_free(btrfs_free_space_cachep, entry); 1966 else 1967 link_free_space(ctl, entry); 1968 } 1969 1970 out: 1971 spin_unlock(&ctl->tree_lock); 1972 1973 return ret; 1974 } 1975 1976 /* 1977 * given a cluster, put all of its extents back into the free space 1978 * cache. If a block group is passed, this function will only free 1979 * a cluster that belongs to the passed block group. 1980 * 1981 * Otherwise, it'll get a reference on the block group pointed to by the 1982 * cluster and remove the cluster from it. 1983 */ 1984 int btrfs_return_cluster_to_free_space( 1985 struct btrfs_block_group_cache *block_group, 1986 struct btrfs_free_cluster *cluster) 1987 { 1988 struct btrfs_free_space_ctl *ctl; 1989 int ret; 1990 1991 /* first, get a safe pointer to the block group */ 1992 spin_lock(&cluster->lock); 1993 if (!block_group) { 1994 block_group = cluster->block_group; 1995 if (!block_group) { 1996 spin_unlock(&cluster->lock); 1997 return 0; 1998 } 1999 } else if (cluster->block_group != block_group) { 2000 /* someone else has already freed it don't redo their work */ 2001 spin_unlock(&cluster->lock); 2002 return 0; 2003 } 2004 atomic_inc(&block_group->count); 2005 spin_unlock(&cluster->lock); 2006 2007 ctl = block_group->free_space_ctl; 2008 2009 /* now return any extents the cluster had on it */ 2010 spin_lock(&ctl->tree_lock); 2011 ret = __btrfs_return_cluster_to_free_space(block_group, cluster); 2012 spin_unlock(&ctl->tree_lock); 2013 2014 /* finally drop our ref */ 2015 btrfs_put_block_group(block_group); 2016 return ret; 2017 } 2018 2019 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group, 2020 struct btrfs_free_cluster *cluster, 2021 struct btrfs_free_space *entry, 2022 u64 bytes, u64 min_start) 2023 { 2024 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 2025 int err; 2026 u64 search_start = cluster->window_start; 2027 u64 search_bytes = bytes; 2028 u64 ret = 0; 2029 2030 search_start = min_start; 2031 search_bytes = bytes; 2032 2033 err = search_bitmap(ctl, entry, &search_start, &search_bytes); 2034 if (err) 2035 return 0; 2036 2037 ret = search_start; 2038 bitmap_clear_bits(ctl, entry, ret, bytes); 2039 2040 return ret; 2041 } 2042 2043 /* 2044 * given a cluster, try to allocate 'bytes' from it, returns 0 2045 * if it couldn't find anything suitably large, or a logical disk offset 2046 * if things worked out 2047 */ 2048 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group, 2049 struct btrfs_free_cluster *cluster, u64 bytes, 2050 u64 min_start) 2051 { 2052 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 2053 struct btrfs_free_space *entry = NULL; 2054 struct rb_node *node; 2055 u64 ret = 0; 2056 2057 spin_lock(&cluster->lock); 2058 if (bytes > cluster->max_size) 2059 goto out; 2060 2061 if (cluster->block_group != block_group) 2062 goto out; 2063 2064 node = rb_first(&cluster->root); 2065 if (!node) 2066 goto out; 2067 2068 entry = rb_entry(node, struct btrfs_free_space, offset_index); 2069 while(1) { 2070 if (entry->bytes < bytes || 2071 (!entry->bitmap && entry->offset < min_start)) { 2072 node = rb_next(&entry->offset_index); 2073 if (!node) 2074 break; 2075 entry = rb_entry(node, struct btrfs_free_space, 2076 offset_index); 2077 continue; 2078 } 2079 2080 if (entry->bitmap) { 2081 ret = btrfs_alloc_from_bitmap(block_group, 2082 cluster, entry, bytes, 2083 min_start); 2084 if (ret == 0) { 2085 node = rb_next(&entry->offset_index); 2086 if (!node) 2087 break; 2088 entry = rb_entry(node, struct btrfs_free_space, 2089 offset_index); 2090 continue; 2091 } 2092 } else { 2093 2094 ret = entry->offset; 2095 2096 entry->offset += bytes; 2097 entry->bytes -= bytes; 2098 } 2099 2100 if (entry->bytes == 0) 2101 rb_erase(&entry->offset_index, &cluster->root); 2102 break; 2103 } 2104 out: 2105 spin_unlock(&cluster->lock); 2106 2107 if (!ret) 2108 return 0; 2109 2110 spin_lock(&ctl->tree_lock); 2111 2112 ctl->free_space -= bytes; 2113 if (entry->bytes == 0) { 2114 ctl->free_extents--; 2115 if (entry->bitmap) { 2116 kfree(entry->bitmap); 2117 ctl->total_bitmaps--; 2118 ctl->op->recalc_thresholds(ctl); 2119 } 2120 kmem_cache_free(btrfs_free_space_cachep, entry); 2121 } 2122 2123 spin_unlock(&ctl->tree_lock); 2124 2125 return ret; 2126 } 2127 2128 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group, 2129 struct btrfs_free_space *entry, 2130 struct btrfs_free_cluster *cluster, 2131 u64 offset, u64 bytes, u64 min_bytes) 2132 { 2133 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 2134 unsigned long next_zero; 2135 unsigned long i; 2136 unsigned long search_bits; 2137 unsigned long total_bits; 2138 unsigned long found_bits; 2139 unsigned long start = 0; 2140 unsigned long total_found = 0; 2141 int ret; 2142 bool found = false; 2143 2144 i = offset_to_bit(entry->offset, block_group->sectorsize, 2145 max_t(u64, offset, entry->offset)); 2146 search_bits = bytes_to_bits(bytes, block_group->sectorsize); 2147 total_bits = bytes_to_bits(min_bytes, block_group->sectorsize); 2148 2149 again: 2150 found_bits = 0; 2151 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i); 2152 i < BITS_PER_BITMAP; 2153 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) { 2154 next_zero = find_next_zero_bit(entry->bitmap, 2155 BITS_PER_BITMAP, i); 2156 if (next_zero - i >= search_bits) { 2157 found_bits = next_zero - i; 2158 break; 2159 } 2160 i = next_zero; 2161 } 2162 2163 if (!found_bits) 2164 return -ENOSPC; 2165 2166 if (!found) { 2167 start = i; 2168 found = true; 2169 } 2170 2171 total_found += found_bits; 2172 2173 if (cluster->max_size < found_bits * block_group->sectorsize) 2174 cluster->max_size = found_bits * block_group->sectorsize; 2175 2176 if (total_found < total_bits) { 2177 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero); 2178 if (i - start > total_bits * 2) { 2179 total_found = 0; 2180 cluster->max_size = 0; 2181 found = false; 2182 } 2183 goto again; 2184 } 2185 2186 cluster->window_start = start * block_group->sectorsize + 2187 entry->offset; 2188 rb_erase(&entry->offset_index, &ctl->free_space_offset); 2189 ret = tree_insert_offset(&cluster->root, entry->offset, 2190 &entry->offset_index, 1); 2191 BUG_ON(ret); 2192 2193 return 0; 2194 } 2195 2196 /* 2197 * This searches the block group for just extents to fill the cluster with. 2198 */ 2199 static noinline int 2200 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group, 2201 struct btrfs_free_cluster *cluster, 2202 struct list_head *bitmaps, u64 offset, u64 bytes, 2203 u64 min_bytes) 2204 { 2205 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 2206 struct btrfs_free_space *first = NULL; 2207 struct btrfs_free_space *entry = NULL; 2208 struct btrfs_free_space *prev = NULL; 2209 struct btrfs_free_space *last; 2210 struct rb_node *node; 2211 u64 window_start; 2212 u64 window_free; 2213 u64 max_extent; 2214 u64 max_gap = 128 * 1024; 2215 2216 entry = tree_search_offset(ctl, offset, 0, 1); 2217 if (!entry) 2218 return -ENOSPC; 2219 2220 /* 2221 * We don't want bitmaps, so just move along until we find a normal 2222 * extent entry. 2223 */ 2224 while (entry->bitmap) { 2225 if (list_empty(&entry->list)) 2226 list_add_tail(&entry->list, bitmaps); 2227 node = rb_next(&entry->offset_index); 2228 if (!node) 2229 return -ENOSPC; 2230 entry = rb_entry(node, struct btrfs_free_space, offset_index); 2231 } 2232 2233 window_start = entry->offset; 2234 window_free = entry->bytes; 2235 max_extent = entry->bytes; 2236 first = entry; 2237 last = entry; 2238 prev = entry; 2239 2240 while (window_free <= min_bytes) { 2241 node = rb_next(&entry->offset_index); 2242 if (!node) 2243 return -ENOSPC; 2244 entry = rb_entry(node, struct btrfs_free_space, offset_index); 2245 2246 if (entry->bitmap) { 2247 if (list_empty(&entry->list)) 2248 list_add_tail(&entry->list, bitmaps); 2249 continue; 2250 } 2251 2252 /* 2253 * we haven't filled the empty size and the window is 2254 * very large. reset and try again 2255 */ 2256 if (entry->offset - (prev->offset + prev->bytes) > max_gap || 2257 entry->offset - window_start > (min_bytes * 2)) { 2258 first = entry; 2259 window_start = entry->offset; 2260 window_free = entry->bytes; 2261 last = entry; 2262 max_extent = entry->bytes; 2263 } else { 2264 last = entry; 2265 window_free += entry->bytes; 2266 if (entry->bytes > max_extent) 2267 max_extent = entry->bytes; 2268 } 2269 prev = entry; 2270 } 2271 2272 cluster->window_start = first->offset; 2273 2274 node = &first->offset_index; 2275 2276 /* 2277 * now we've found our entries, pull them out of the free space 2278 * cache and put them into the cluster rbtree 2279 */ 2280 do { 2281 int ret; 2282 2283 entry = rb_entry(node, struct btrfs_free_space, offset_index); 2284 node = rb_next(&entry->offset_index); 2285 if (entry->bitmap) 2286 continue; 2287 2288 rb_erase(&entry->offset_index, &ctl->free_space_offset); 2289 ret = tree_insert_offset(&cluster->root, entry->offset, 2290 &entry->offset_index, 0); 2291 BUG_ON(ret); 2292 } while (node && entry != last); 2293 2294 cluster->max_size = max_extent; 2295 2296 return 0; 2297 } 2298 2299 /* 2300 * This specifically looks for bitmaps that may work in the cluster, we assume 2301 * that we have already failed to find extents that will work. 2302 */ 2303 static noinline int 2304 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group, 2305 struct btrfs_free_cluster *cluster, 2306 struct list_head *bitmaps, u64 offset, u64 bytes, 2307 u64 min_bytes) 2308 { 2309 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 2310 struct btrfs_free_space *entry; 2311 struct rb_node *node; 2312 int ret = -ENOSPC; 2313 2314 if (ctl->total_bitmaps == 0) 2315 return -ENOSPC; 2316 2317 /* 2318 * First check our cached list of bitmaps and see if there is an entry 2319 * here that will work. 2320 */ 2321 list_for_each_entry(entry, bitmaps, list) { 2322 if (entry->bytes < min_bytes) 2323 continue; 2324 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset, 2325 bytes, min_bytes); 2326 if (!ret) 2327 return 0; 2328 } 2329 2330 /* 2331 * If we do have entries on our list and we are here then we didn't find 2332 * anything, so go ahead and get the next entry after the last entry in 2333 * this list and start the search from there. 2334 */ 2335 if (!list_empty(bitmaps)) { 2336 entry = list_entry(bitmaps->prev, struct btrfs_free_space, 2337 list); 2338 node = rb_next(&entry->offset_index); 2339 if (!node) 2340 return -ENOSPC; 2341 entry = rb_entry(node, struct btrfs_free_space, offset_index); 2342 goto search; 2343 } 2344 2345 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1); 2346 if (!entry) 2347 return -ENOSPC; 2348 2349 search: 2350 node = &entry->offset_index; 2351 do { 2352 entry = rb_entry(node, struct btrfs_free_space, offset_index); 2353 node = rb_next(&entry->offset_index); 2354 if (!entry->bitmap) 2355 continue; 2356 if (entry->bytes < min_bytes) 2357 continue; 2358 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset, 2359 bytes, min_bytes); 2360 } while (ret && node); 2361 2362 return ret; 2363 } 2364 2365 /* 2366 * here we try to find a cluster of blocks in a block group. The goal 2367 * is to find at least bytes free and up to empty_size + bytes free. 2368 * We might not find them all in one contiguous area. 2369 * 2370 * returns zero and sets up cluster if things worked out, otherwise 2371 * it returns -enospc 2372 */ 2373 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans, 2374 struct btrfs_root *root, 2375 struct btrfs_block_group_cache *block_group, 2376 struct btrfs_free_cluster *cluster, 2377 u64 offset, u64 bytes, u64 empty_size) 2378 { 2379 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 2380 struct list_head bitmaps; 2381 struct btrfs_free_space *entry, *tmp; 2382 u64 min_bytes; 2383 int ret; 2384 2385 /* for metadata, allow allocates with more holes */ 2386 if (btrfs_test_opt(root, SSD_SPREAD)) { 2387 min_bytes = bytes + empty_size; 2388 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) { 2389 /* 2390 * we want to do larger allocations when we are 2391 * flushing out the delayed refs, it helps prevent 2392 * making more work as we go along. 2393 */ 2394 if (trans->transaction->delayed_refs.flushing) 2395 min_bytes = max(bytes, (bytes + empty_size) >> 1); 2396 else 2397 min_bytes = max(bytes, (bytes + empty_size) >> 4); 2398 } else 2399 min_bytes = max(bytes, (bytes + empty_size) >> 2); 2400 2401 spin_lock(&ctl->tree_lock); 2402 2403 /* 2404 * If we know we don't have enough space to make a cluster don't even 2405 * bother doing all the work to try and find one. 2406 */ 2407 if (ctl->free_space < min_bytes) { 2408 spin_unlock(&ctl->tree_lock); 2409 return -ENOSPC; 2410 } 2411 2412 spin_lock(&cluster->lock); 2413 2414 /* someone already found a cluster, hooray */ 2415 if (cluster->block_group) { 2416 ret = 0; 2417 goto out; 2418 } 2419 2420 INIT_LIST_HEAD(&bitmaps); 2421 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset, 2422 bytes, min_bytes); 2423 if (ret) 2424 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps, 2425 offset, bytes, min_bytes); 2426 2427 /* Clear our temporary list */ 2428 list_for_each_entry_safe(entry, tmp, &bitmaps, list) 2429 list_del_init(&entry->list); 2430 2431 if (!ret) { 2432 atomic_inc(&block_group->count); 2433 list_add_tail(&cluster->block_group_list, 2434 &block_group->cluster_list); 2435 cluster->block_group = block_group; 2436 } 2437 out: 2438 spin_unlock(&cluster->lock); 2439 spin_unlock(&ctl->tree_lock); 2440 2441 return ret; 2442 } 2443 2444 /* 2445 * simple code to zero out a cluster 2446 */ 2447 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster) 2448 { 2449 spin_lock_init(&cluster->lock); 2450 spin_lock_init(&cluster->refill_lock); 2451 cluster->root = RB_ROOT; 2452 cluster->max_size = 0; 2453 INIT_LIST_HEAD(&cluster->block_group_list); 2454 cluster->block_group = NULL; 2455 } 2456 2457 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group, 2458 u64 *trimmed, u64 start, u64 end, u64 minlen) 2459 { 2460 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; 2461 struct btrfs_free_space *entry = NULL; 2462 struct btrfs_fs_info *fs_info = block_group->fs_info; 2463 u64 bytes = 0; 2464 u64 actually_trimmed; 2465 int ret = 0; 2466 2467 *trimmed = 0; 2468 2469 while (start < end) { 2470 spin_lock(&ctl->tree_lock); 2471 2472 if (ctl->free_space < minlen) { 2473 spin_unlock(&ctl->tree_lock); 2474 break; 2475 } 2476 2477 entry = tree_search_offset(ctl, start, 0, 1); 2478 if (!entry) 2479 entry = tree_search_offset(ctl, 2480 offset_to_bitmap(ctl, start), 2481 1, 1); 2482 2483 if (!entry || entry->offset >= end) { 2484 spin_unlock(&ctl->tree_lock); 2485 break; 2486 } 2487 2488 if (entry->bitmap) { 2489 ret = search_bitmap(ctl, entry, &start, &bytes); 2490 if (!ret) { 2491 if (start >= end) { 2492 spin_unlock(&ctl->tree_lock); 2493 break; 2494 } 2495 bytes = min(bytes, end - start); 2496 bitmap_clear_bits(ctl, entry, start, bytes); 2497 if (entry->bytes == 0) 2498 free_bitmap(ctl, entry); 2499 } else { 2500 start = entry->offset + BITS_PER_BITMAP * 2501 block_group->sectorsize; 2502 spin_unlock(&ctl->tree_lock); 2503 ret = 0; 2504 continue; 2505 } 2506 } else { 2507 start = entry->offset; 2508 bytes = min(entry->bytes, end - start); 2509 unlink_free_space(ctl, entry); 2510 kmem_cache_free(btrfs_free_space_cachep, entry); 2511 } 2512 2513 spin_unlock(&ctl->tree_lock); 2514 2515 if (bytes >= minlen) { 2516 int update_ret; 2517 update_ret = btrfs_update_reserved_bytes(block_group, 2518 bytes, 1, 1); 2519 2520 ret = btrfs_error_discard_extent(fs_info->extent_root, 2521 start, 2522 bytes, 2523 &actually_trimmed); 2524 2525 btrfs_add_free_space(block_group, start, bytes); 2526 if (!update_ret) 2527 btrfs_update_reserved_bytes(block_group, 2528 bytes, 0, 1); 2529 2530 if (ret) 2531 break; 2532 *trimmed += actually_trimmed; 2533 } 2534 start += bytes; 2535 bytes = 0; 2536 2537 if (fatal_signal_pending(current)) { 2538 ret = -ERESTARTSYS; 2539 break; 2540 } 2541 2542 cond_resched(); 2543 } 2544 2545 return ret; 2546 } 2547 2548 /* 2549 * Find the left-most item in the cache tree, and then return the 2550 * smallest inode number in the item. 2551 * 2552 * Note: the returned inode number may not be the smallest one in 2553 * the tree, if the left-most item is a bitmap. 2554 */ 2555 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root) 2556 { 2557 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl; 2558 struct btrfs_free_space *entry = NULL; 2559 u64 ino = 0; 2560 2561 spin_lock(&ctl->tree_lock); 2562 2563 if (RB_EMPTY_ROOT(&ctl->free_space_offset)) 2564 goto out; 2565 2566 entry = rb_entry(rb_first(&ctl->free_space_offset), 2567 struct btrfs_free_space, offset_index); 2568 2569 if (!entry->bitmap) { 2570 ino = entry->offset; 2571 2572 unlink_free_space(ctl, entry); 2573 entry->offset++; 2574 entry->bytes--; 2575 if (!entry->bytes) 2576 kmem_cache_free(btrfs_free_space_cachep, entry); 2577 else 2578 link_free_space(ctl, entry); 2579 } else { 2580 u64 offset = 0; 2581 u64 count = 1; 2582 int ret; 2583 2584 ret = search_bitmap(ctl, entry, &offset, &count); 2585 BUG_ON(ret); 2586 2587 ino = offset; 2588 bitmap_clear_bits(ctl, entry, offset, 1); 2589 if (entry->bytes == 0) 2590 free_bitmap(ctl, entry); 2591 } 2592 out: 2593 spin_unlock(&ctl->tree_lock); 2594 2595 return ino; 2596 } 2597 2598 struct inode *lookup_free_ino_inode(struct btrfs_root *root, 2599 struct btrfs_path *path) 2600 { 2601 struct inode *inode = NULL; 2602 2603 spin_lock(&root->cache_lock); 2604 if (root->cache_inode) 2605 inode = igrab(root->cache_inode); 2606 spin_unlock(&root->cache_lock); 2607 if (inode) 2608 return inode; 2609 2610 inode = __lookup_free_space_inode(root, path, 0); 2611 if (IS_ERR(inode)) 2612 return inode; 2613 2614 spin_lock(&root->cache_lock); 2615 if (!btrfs_fs_closing(root->fs_info)) 2616 root->cache_inode = igrab(inode); 2617 spin_unlock(&root->cache_lock); 2618 2619 return inode; 2620 } 2621 2622 int create_free_ino_inode(struct btrfs_root *root, 2623 struct btrfs_trans_handle *trans, 2624 struct btrfs_path *path) 2625 { 2626 return __create_free_space_inode(root, trans, path, 2627 BTRFS_FREE_INO_OBJECTID, 0); 2628 } 2629 2630 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root) 2631 { 2632 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; 2633 struct btrfs_path *path; 2634 struct inode *inode; 2635 int ret = 0; 2636 u64 root_gen = btrfs_root_generation(&root->root_item); 2637 2638 if (!btrfs_test_opt(root, INODE_MAP_CACHE)) 2639 return 0; 2640 2641 /* 2642 * If we're unmounting then just return, since this does a search on the 2643 * normal root and not the commit root and we could deadlock. 2644 */ 2645 if (btrfs_fs_closing(fs_info)) 2646 return 0; 2647 2648 path = btrfs_alloc_path(); 2649 if (!path) 2650 return 0; 2651 2652 inode = lookup_free_ino_inode(root, path); 2653 if (IS_ERR(inode)) 2654 goto out; 2655 2656 if (root_gen != BTRFS_I(inode)->generation) 2657 goto out_put; 2658 2659 ret = __load_free_space_cache(root, inode, ctl, path, 0); 2660 2661 if (ret < 0) 2662 printk(KERN_ERR "btrfs: failed to load free ino cache for " 2663 "root %llu\n", root->root_key.objectid); 2664 out_put: 2665 iput(inode); 2666 out: 2667 btrfs_free_path(path); 2668 return ret; 2669 } 2670 2671 int btrfs_write_out_ino_cache(struct btrfs_root *root, 2672 struct btrfs_trans_handle *trans, 2673 struct btrfs_path *path) 2674 { 2675 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; 2676 struct inode *inode; 2677 int ret; 2678 2679 if (!btrfs_test_opt(root, INODE_MAP_CACHE)) 2680 return 0; 2681 2682 inode = lookup_free_ino_inode(root, path); 2683 if (IS_ERR(inode)) 2684 return 0; 2685 2686 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0); 2687 if (ret < 0) 2688 printk(KERN_ERR "btrfs: failed to write free ino cache " 2689 "for root %llu\n", root->root_key.objectid); 2690 2691 iput(inode); 2692 return ret; 2693 } 2694