1 #include <linux/bitops.h> 2 #include <linux/slab.h> 3 #include <linux/bio.h> 4 #include <linux/mm.h> 5 #include <linux/gfp.h> 6 #include <linux/pagemap.h> 7 #include <linux/page-flags.h> 8 #include <linux/module.h> 9 #include <linux/spinlock.h> 10 #include <linux/blkdev.h> 11 #include "extent_map.h" 12 13 static struct kmem_cache *extent_map_cache; 14 static struct kmem_cache *extent_state_cache; 15 16 struct tree_entry { 17 u64 start; 18 u64 end; 19 int in_tree; 20 struct rb_node rb_node; 21 }; 22 23 /* bits for the extent state */ 24 #define EXTENT_DIRTY 1 25 #define EXTENT_WRITEBACK (1 << 1) 26 #define EXTENT_UPTODATE (1 << 2) 27 #define EXTENT_LOCKED (1 << 3) 28 #define EXTENT_NEW (1 << 4) 29 #define EXTENT_DELALLOC (1 << 5) 30 31 #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK) 32 33 static LIST_HEAD(all_states); 34 spinlock_t state_lock = SPIN_LOCK_UNLOCKED; 35 36 void __init extent_map_init(void) 37 { 38 extent_map_cache = kmem_cache_create("extent_map", 39 sizeof(struct extent_map), 0, 40 SLAB_RECLAIM_ACCOUNT | 41 SLAB_DESTROY_BY_RCU, 42 NULL); 43 extent_state_cache = kmem_cache_create("extent_state", 44 sizeof(struct extent_state), 0, 45 SLAB_RECLAIM_ACCOUNT | 46 SLAB_DESTROY_BY_RCU, 47 NULL); 48 } 49 50 void __exit extent_map_exit(void) 51 { 52 while(!list_empty(&all_states)) { 53 struct extent_state *state; 54 struct list_head *cur = all_states.next; 55 state = list_entry(cur, struct extent_state, list); 56 printk("found leaked state %Lu %Lu state %d in_tree %d\n", 57 state->start, state->end, state->state, state->in_tree); 58 list_del(&state->list); 59 kfree(state); 60 } 61 if (extent_map_cache) 62 kmem_cache_destroy(extent_map_cache); 63 if (extent_state_cache) 64 kmem_cache_destroy(extent_state_cache); 65 } 66 67 void extent_map_tree_init(struct extent_map_tree *tree, 68 struct address_space *mapping, gfp_t mask) 69 { 70 tree->map.rb_node = NULL; 71 tree->state.rb_node = NULL; 72 rwlock_init(&tree->lock); 73 tree->mapping = mapping; 74 } 75 EXPORT_SYMBOL(extent_map_tree_init); 76 77 struct extent_map *alloc_extent_map(gfp_t mask) 78 { 79 struct extent_map *em; 80 em = kmem_cache_alloc(extent_map_cache, mask); 81 if (!em || IS_ERR(em)) 82 return em; 83 em->in_tree = 0; 84 atomic_set(&em->refs, 1); 85 return em; 86 } 87 EXPORT_SYMBOL(alloc_extent_map); 88 89 void free_extent_map(struct extent_map *em) 90 { 91 if (atomic_dec_and_test(&em->refs)) { 92 WARN_ON(em->in_tree); 93 kmem_cache_free(extent_map_cache, em); 94 } 95 } 96 EXPORT_SYMBOL(free_extent_map); 97 98 99 struct extent_state *alloc_extent_state(gfp_t mask) 100 { 101 struct extent_state *state; 102 state = kmem_cache_alloc(extent_state_cache, mask); 103 if (!state || IS_ERR(state)) 104 return state; 105 state->state = 0; 106 state->in_tree = 0; 107 atomic_set(&state->refs, 1); 108 init_waitqueue_head(&state->wq); 109 spin_lock_irq(&state_lock); 110 list_add(&state->list, &all_states); 111 spin_unlock_irq(&state_lock); 112 return state; 113 } 114 EXPORT_SYMBOL(alloc_extent_state); 115 116 void free_extent_state(struct extent_state *state) 117 { 118 if (atomic_dec_and_test(&state->refs)) { 119 WARN_ON(state->in_tree); 120 spin_lock_irq(&state_lock); 121 list_del_init(&state->list); 122 spin_unlock_irq(&state_lock); 123 kmem_cache_free(extent_state_cache, state); 124 } 125 } 126 EXPORT_SYMBOL(free_extent_state); 127 128 static struct rb_node *tree_insert(struct rb_root *root, u64 offset, 129 struct rb_node *node) 130 { 131 struct rb_node ** p = &root->rb_node; 132 struct rb_node * parent = NULL; 133 struct tree_entry *entry; 134 135 while(*p) { 136 parent = *p; 137 entry = rb_entry(parent, struct tree_entry, rb_node); 138 139 if (offset < entry->start) 140 p = &(*p)->rb_left; 141 else if (offset > entry->end) 142 p = &(*p)->rb_right; 143 else 144 return parent; 145 } 146 147 entry = rb_entry(node, struct tree_entry, rb_node); 148 entry->in_tree = 1; 149 rb_link_node(node, parent, p); 150 rb_insert_color(node, root); 151 return NULL; 152 } 153 154 static struct rb_node *__tree_search(struct rb_root *root, u64 offset, 155 struct rb_node **prev_ret) 156 { 157 struct rb_node * n = root->rb_node; 158 struct rb_node *prev = NULL; 159 struct tree_entry *entry; 160 struct tree_entry *prev_entry = NULL; 161 162 while(n) { 163 entry = rb_entry(n, struct tree_entry, rb_node); 164 prev = n; 165 prev_entry = entry; 166 167 if (offset < entry->start) 168 n = n->rb_left; 169 else if (offset > entry->end) 170 n = n->rb_right; 171 else 172 return n; 173 } 174 if (!prev_ret) 175 return NULL; 176 while(prev && offset > prev_entry->end) { 177 prev = rb_next(prev); 178 prev_entry = rb_entry(prev, struct tree_entry, rb_node); 179 } 180 *prev_ret = prev; 181 return NULL; 182 } 183 184 static inline struct rb_node *tree_search(struct rb_root *root, u64 offset) 185 { 186 struct rb_node *prev; 187 struct rb_node *ret; 188 ret = __tree_search(root, offset, &prev); 189 if (!ret) 190 return prev; 191 return ret; 192 } 193 194 static int tree_delete(struct rb_root *root, u64 offset) 195 { 196 struct rb_node *node; 197 struct tree_entry *entry; 198 199 node = __tree_search(root, offset, NULL); 200 if (!node) 201 return -ENOENT; 202 entry = rb_entry(node, struct tree_entry, rb_node); 203 entry->in_tree = 0; 204 rb_erase(node, root); 205 return 0; 206 } 207 208 /* 209 * add_extent_mapping tries a simple backward merge with existing 210 * mappings. The extent_map struct passed in will be inserted into 211 * the tree directly (no copies made, just a reference taken). 212 */ 213 int add_extent_mapping(struct extent_map_tree *tree, 214 struct extent_map *em) 215 { 216 int ret = 0; 217 struct extent_map *prev = NULL; 218 struct rb_node *rb; 219 220 write_lock_irq(&tree->lock); 221 rb = tree_insert(&tree->map, em->end, &em->rb_node); 222 if (rb) { 223 prev = rb_entry(rb, struct extent_map, rb_node); 224 printk("found extent map %Lu %Lu on insert of %Lu %Lu\n", prev->start, prev->end, em->start, em->end); 225 ret = -EEXIST; 226 goto out; 227 } 228 atomic_inc(&em->refs); 229 if (em->start != 0) { 230 rb = rb_prev(&em->rb_node); 231 if (rb) 232 prev = rb_entry(rb, struct extent_map, rb_node); 233 if (prev && prev->end + 1 == em->start && 234 ((em->block_start == 0 && prev->block_start == 0) || 235 (em->block_start == prev->block_end + 1))) { 236 em->start = prev->start; 237 em->block_start = prev->block_start; 238 rb_erase(&prev->rb_node, &tree->map); 239 prev->in_tree = 0; 240 free_extent_map(prev); 241 } 242 } 243 out: 244 write_unlock_irq(&tree->lock); 245 return ret; 246 } 247 EXPORT_SYMBOL(add_extent_mapping); 248 249 /* 250 * lookup_extent_mapping returns the first extent_map struct in the 251 * tree that intersects the [start, end] (inclusive) range. There may 252 * be additional objects in the tree that intersect, so check the object 253 * returned carefully to make sure you don't need additional lookups. 254 */ 255 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, 256 u64 start, u64 end) 257 { 258 struct extent_map *em; 259 struct rb_node *rb_node; 260 261 read_lock_irq(&tree->lock); 262 rb_node = tree_search(&tree->map, start); 263 if (!rb_node) { 264 em = NULL; 265 goto out; 266 } 267 if (IS_ERR(rb_node)) { 268 em = ERR_PTR(PTR_ERR(rb_node)); 269 goto out; 270 } 271 em = rb_entry(rb_node, struct extent_map, rb_node); 272 if (em->end < start || em->start > end) { 273 em = NULL; 274 goto out; 275 } 276 atomic_inc(&em->refs); 277 out: 278 read_unlock_irq(&tree->lock); 279 return em; 280 } 281 EXPORT_SYMBOL(lookup_extent_mapping); 282 283 /* 284 * removes an extent_map struct from the tree. No reference counts are 285 * dropped, and no checks are done to see if the range is in use 286 */ 287 int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) 288 { 289 int ret; 290 291 write_lock_irq(&tree->lock); 292 ret = tree_delete(&tree->map, em->end); 293 write_unlock_irq(&tree->lock); 294 return ret; 295 } 296 EXPORT_SYMBOL(remove_extent_mapping); 297 298 /* 299 * utility function to look for merge candidates inside a given range. 300 * Any extents with matching state are merged together into a single 301 * extent in the tree. Extents with EXTENT_IO in their state field 302 * are not merged because the end_io handlers need to be able to do 303 * operations on them without sleeping (or doing allocations/splits). 304 * 305 * This should be called with the tree lock held. 306 */ 307 static int merge_state(struct extent_map_tree *tree, 308 struct extent_state *state) 309 { 310 struct extent_state *other; 311 struct rb_node *other_node; 312 313 if (state->state & EXTENT_IOBITS) 314 return 0; 315 316 other_node = rb_prev(&state->rb_node); 317 if (other_node) { 318 other = rb_entry(other_node, struct extent_state, rb_node); 319 if (other->end == state->start - 1 && 320 other->state == state->state) { 321 state->start = other->start; 322 other->in_tree = 0; 323 rb_erase(&other->rb_node, &tree->state); 324 free_extent_state(other); 325 } 326 } 327 other_node = rb_next(&state->rb_node); 328 if (other_node) { 329 other = rb_entry(other_node, struct extent_state, rb_node); 330 if (other->start == state->end + 1 && 331 other->state == state->state) { 332 other->start = state->start; 333 state->in_tree = 0; 334 rb_erase(&state->rb_node, &tree->state); 335 free_extent_state(state); 336 } 337 } 338 return 0; 339 } 340 341 /* 342 * insert an extent_state struct into the tree. 'bits' are set on the 343 * struct before it is inserted. 344 * 345 * This may return -EEXIST if the extent is already there, in which case the 346 * state struct is freed. 347 * 348 * The tree lock is not taken internally. This is a utility function and 349 * probably isn't what you want to call (see set/clear_extent_bit). 350 */ 351 static int insert_state(struct extent_map_tree *tree, 352 struct extent_state *state, u64 start, u64 end, 353 int bits) 354 { 355 struct rb_node *node; 356 357 if (end < start) { 358 printk("end < start %Lu %Lu\n", end, start); 359 WARN_ON(1); 360 } 361 state->state |= bits; 362 state->start = start; 363 state->end = end; 364 if ((end & 4095) == 0) { 365 printk("insert state %Lu %Lu strange end\n", start, end); 366 WARN_ON(1); 367 } 368 node = tree_insert(&tree->state, end, &state->rb_node); 369 if (node) { 370 struct extent_state *found; 371 found = rb_entry(node, struct extent_state, rb_node); 372 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end); 373 free_extent_state(state); 374 return -EEXIST; 375 } 376 merge_state(tree, state); 377 return 0; 378 } 379 380 /* 381 * split a given extent state struct in two, inserting the preallocated 382 * struct 'prealloc' as the newly created second half. 'split' indicates an 383 * offset inside 'orig' where it should be split. 384 * 385 * Before calling, 386 * the tree has 'orig' at [orig->start, orig->end]. After calling, there 387 * are two extent state structs in the tree: 388 * prealloc: [orig->start, split - 1] 389 * orig: [ split, orig->end ] 390 * 391 * The tree locks are not taken by this function. They need to be held 392 * by the caller. 393 */ 394 static int split_state(struct extent_map_tree *tree, struct extent_state *orig, 395 struct extent_state *prealloc, u64 split) 396 { 397 struct rb_node *node; 398 prealloc->start = orig->start; 399 prealloc->end = split - 1; 400 prealloc->state = orig->state; 401 orig->start = split; 402 if ((prealloc->end & 4095) == 0) { 403 printk("insert state %Lu %Lu strange end\n", prealloc->start, 404 prealloc->end); 405 WARN_ON(1); 406 } 407 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node); 408 if (node) { 409 struct extent_state *found; 410 found = rb_entry(node, struct extent_state, rb_node); 411 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end); 412 free_extent_state(prealloc); 413 return -EEXIST; 414 } 415 return 0; 416 } 417 418 /* 419 * utility function to clear some bits in an extent state struct. 420 * it will optionally wake up any one waiting on this state (wake == 1), or 421 * forcibly remove the state from the tree (delete == 1). 422 * 423 * If no bits are set on the state struct after clearing things, the 424 * struct is freed and removed from the tree 425 */ 426 static int clear_state_bit(struct extent_map_tree *tree, 427 struct extent_state *state, int bits, int wake, 428 int delete) 429 { 430 int ret = state->state & bits; 431 state->state &= ~bits; 432 if (wake) 433 wake_up(&state->wq); 434 if (delete || state->state == 0) { 435 if (state->in_tree) { 436 rb_erase(&state->rb_node, &tree->state); 437 state->in_tree = 0; 438 free_extent_state(state); 439 } else { 440 WARN_ON(1); 441 } 442 } else { 443 merge_state(tree, state); 444 } 445 return ret; 446 } 447 448 /* 449 * clear some bits on a range in the tree. This may require splitting 450 * or inserting elements in the tree, so the gfp mask is used to 451 * indicate which allocations or sleeping are allowed. 452 * 453 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove 454 * the given range from the tree regardless of state (ie for truncate). 455 * 456 * the range [start, end] is inclusive. 457 * 458 * This takes the tree lock, and returns < 0 on error, > 0 if any of the 459 * bits were already set, or zero if none of the bits were already set. 460 */ 461 int clear_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, 462 int bits, int wake, int delete, gfp_t mask) 463 { 464 struct extent_state *state; 465 struct extent_state *prealloc = NULL; 466 struct rb_node *node; 467 int err; 468 int set = 0; 469 470 again: 471 if (!prealloc && (mask & __GFP_WAIT)) { 472 prealloc = alloc_extent_state(mask); 473 if (!prealloc) 474 return -ENOMEM; 475 } 476 477 write_lock_irq(&tree->lock); 478 /* 479 * this search will find the extents that end after 480 * our range starts 481 */ 482 node = tree_search(&tree->state, start); 483 if (!node) 484 goto out; 485 state = rb_entry(node, struct extent_state, rb_node); 486 if (state->start > end) 487 goto out; 488 WARN_ON(state->end < start); 489 490 /* 491 * | ---- desired range ---- | 492 * | state | or 493 * | ------------- state -------------- | 494 * 495 * We need to split the extent we found, and may flip 496 * bits on second half. 497 * 498 * If the extent we found extends past our range, we 499 * just split and search again. It'll get split again 500 * the next time though. 501 * 502 * If the extent we found is inside our range, we clear 503 * the desired bit on it. 504 */ 505 506 if (state->start < start) { 507 err = split_state(tree, state, prealloc, start); 508 BUG_ON(err == -EEXIST); 509 prealloc = NULL; 510 if (err) 511 goto out; 512 if (state->end <= end) { 513 start = state->end + 1; 514 set |= clear_state_bit(tree, state, bits, 515 wake, delete); 516 } else { 517 start = state->start; 518 } 519 goto search_again; 520 } 521 /* 522 * | ---- desired range ---- | 523 * | state | 524 * We need to split the extent, and clear the bit 525 * on the first half 526 */ 527 if (state->start <= end && state->end > end) { 528 err = split_state(tree, state, prealloc, end + 1); 529 BUG_ON(err == -EEXIST); 530 531 if (wake) 532 wake_up(&state->wq); 533 set |= clear_state_bit(tree, prealloc, bits, 534 wake, delete); 535 prealloc = NULL; 536 goto out; 537 } 538 539 start = state->end + 1; 540 set |= clear_state_bit(tree, state, bits, wake, delete); 541 goto search_again; 542 543 out: 544 write_unlock_irq(&tree->lock); 545 if (prealloc) 546 free_extent_state(prealloc); 547 548 return set; 549 550 search_again: 551 if (start >= end) 552 goto out; 553 write_unlock_irq(&tree->lock); 554 if (mask & __GFP_WAIT) 555 cond_resched(); 556 goto again; 557 } 558 EXPORT_SYMBOL(clear_extent_bit); 559 560 static int wait_on_state(struct extent_map_tree *tree, 561 struct extent_state *state) 562 { 563 DEFINE_WAIT(wait); 564 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE); 565 read_unlock_irq(&tree->lock); 566 schedule(); 567 read_lock_irq(&tree->lock); 568 finish_wait(&state->wq, &wait); 569 return 0; 570 } 571 572 /* 573 * waits for one or more bits to clear on a range in the state tree. 574 * The range [start, end] is inclusive. 575 * The tree lock is taken by this function 576 */ 577 int wait_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits) 578 { 579 struct extent_state *state; 580 struct rb_node *node; 581 582 read_lock_irq(&tree->lock); 583 again: 584 while (1) { 585 /* 586 * this search will find all the extents that end after 587 * our range starts 588 */ 589 node = tree_search(&tree->state, start); 590 if (!node) 591 break; 592 593 state = rb_entry(node, struct extent_state, rb_node); 594 595 if (state->start > end) 596 goto out; 597 598 if (state->state & bits) { 599 start = state->start; 600 atomic_inc(&state->refs); 601 wait_on_state(tree, state); 602 free_extent_state(state); 603 goto again; 604 } 605 start = state->end + 1; 606 607 if (start > end) 608 break; 609 610 if (need_resched()) { 611 read_unlock_irq(&tree->lock); 612 cond_resched(); 613 read_lock_irq(&tree->lock); 614 } 615 } 616 out: 617 read_unlock_irq(&tree->lock); 618 return 0; 619 } 620 EXPORT_SYMBOL(wait_extent_bit); 621 622 /* 623 * set some bits on a range in the tree. This may require allocations 624 * or sleeping, so the gfp mask is used to indicate what is allowed. 625 * 626 * If 'exclusive' == 1, this will fail with -EEXIST if some part of the 627 * range already has the desired bits set. The start of the existing 628 * range is returned in failed_start in this case. 629 * 630 * [start, end] is inclusive 631 * This takes the tree lock. 632 */ 633 int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits, 634 int exclusive, u64 *failed_start, gfp_t mask) 635 { 636 struct extent_state *state; 637 struct extent_state *prealloc = NULL; 638 struct rb_node *node; 639 int err = 0; 640 int set; 641 u64 last_start; 642 u64 last_end; 643 again: 644 if (!prealloc && (mask & __GFP_WAIT)) { 645 prealloc = alloc_extent_state(mask); 646 if (!prealloc) 647 return -ENOMEM; 648 } 649 650 write_lock_irq(&tree->lock); 651 /* 652 * this search will find all the extents that end after 653 * our range starts. 654 */ 655 node = tree_search(&tree->state, start); 656 if (!node) { 657 err = insert_state(tree, prealloc, start, end, bits); 658 prealloc = NULL; 659 BUG_ON(err == -EEXIST); 660 goto out; 661 } 662 663 state = rb_entry(node, struct extent_state, rb_node); 664 last_start = state->start; 665 last_end = state->end; 666 667 /* 668 * | ---- desired range ---- | 669 * | state | 670 * 671 * Just lock what we found and keep going 672 */ 673 if (state->start == start && state->end <= end) { 674 set = state->state & bits; 675 if (set && exclusive) { 676 *failed_start = state->start; 677 err = -EEXIST; 678 goto out; 679 } 680 state->state |= bits; 681 start = state->end + 1; 682 merge_state(tree, state); 683 goto search_again; 684 } 685 686 /* 687 * | ---- desired range ---- | 688 * | state | 689 * or 690 * | ------------- state -------------- | 691 * 692 * We need to split the extent we found, and may flip bits on 693 * second half. 694 * 695 * If the extent we found extends past our 696 * range, we just split and search again. It'll get split 697 * again the next time though. 698 * 699 * If the extent we found is inside our range, we set the 700 * desired bit on it. 701 */ 702 if (state->start < start) { 703 set = state->state & bits; 704 if (exclusive && set) { 705 *failed_start = start; 706 err = -EEXIST; 707 goto out; 708 } 709 err = split_state(tree, state, prealloc, start); 710 BUG_ON(err == -EEXIST); 711 prealloc = NULL; 712 if (err) 713 goto out; 714 if (state->end <= end) { 715 state->state |= bits; 716 start = state->end + 1; 717 merge_state(tree, state); 718 } else { 719 start = state->start; 720 } 721 goto search_again; 722 } 723 /* 724 * | ---- desired range ---- | 725 * | state | 726 * We need to split the extent, and set the bit 727 * on the first half 728 */ 729 if (state->start <= end && state->end > end) { 730 set = state->state & bits; 731 if (exclusive && set) { 732 *failed_start = start; 733 err = -EEXIST; 734 goto out; 735 } 736 err = split_state(tree, state, prealloc, end + 1); 737 BUG_ON(err == -EEXIST); 738 739 prealloc->state |= bits; 740 merge_state(tree, prealloc); 741 prealloc = NULL; 742 goto out; 743 } 744 745 /* 746 * | ---- desired range ---- | 747 * | state | or | state | 748 * 749 * There's a hole, we need to insert something in it and 750 * ignore the extent we found. 751 */ 752 if (state->start > start) { 753 u64 this_end; 754 if (end < last_start) 755 this_end = end; 756 else 757 this_end = last_start -1; 758 err = insert_state(tree, prealloc, start, this_end, 759 bits); 760 prealloc = NULL; 761 BUG_ON(err == -EEXIST); 762 if (err) 763 goto out; 764 start = this_end + 1; 765 goto search_again; 766 } 767 goto search_again; 768 769 out: 770 write_unlock_irq(&tree->lock); 771 if (prealloc) 772 free_extent_state(prealloc); 773 774 return err; 775 776 search_again: 777 if (start > end) 778 goto out; 779 write_unlock_irq(&tree->lock); 780 if (mask & __GFP_WAIT) 781 cond_resched(); 782 goto again; 783 } 784 EXPORT_SYMBOL(set_extent_bit); 785 786 /* wrappers around set/clear extent bit */ 787 int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end, 788 gfp_t mask) 789 { 790 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL, 791 mask); 792 } 793 EXPORT_SYMBOL(set_extent_dirty); 794 795 int clear_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end, 796 gfp_t mask) 797 { 798 return clear_extent_bit(tree, start, end, EXTENT_DIRTY, 0, 0, mask); 799 } 800 EXPORT_SYMBOL(clear_extent_dirty); 801 802 int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end, 803 gfp_t mask) 804 { 805 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL, 806 mask); 807 } 808 EXPORT_SYMBOL(set_extent_new); 809 810 int clear_extent_new(struct extent_map_tree *tree, u64 start, u64 end, 811 gfp_t mask) 812 { 813 return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask); 814 } 815 EXPORT_SYMBOL(clear_extent_new); 816 817 int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end, 818 gfp_t mask) 819 { 820 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL, 821 mask); 822 } 823 EXPORT_SYMBOL(set_extent_uptodate); 824 825 int clear_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end, 826 gfp_t mask) 827 { 828 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask); 829 } 830 EXPORT_SYMBOL(clear_extent_uptodate); 831 832 int set_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end, 833 gfp_t mask) 834 { 835 return set_extent_bit(tree, start, end, EXTENT_WRITEBACK, 836 0, NULL, mask); 837 } 838 EXPORT_SYMBOL(set_extent_writeback); 839 840 int clear_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end, 841 gfp_t mask) 842 { 843 return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask); 844 } 845 EXPORT_SYMBOL(clear_extent_writeback); 846 847 int wait_on_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end) 848 { 849 return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK); 850 } 851 EXPORT_SYMBOL(wait_on_extent_writeback); 852 853 /* 854 * locks a range in ascending order, waiting for any locked regions 855 * it hits on the way. [start,end] are inclusive, and this will sleep. 856 */ 857 int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask) 858 { 859 int err; 860 u64 failed_start; 861 while (1) { 862 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 863 &failed_start, mask); 864 if (err == -EEXIST && (mask & __GFP_WAIT)) { 865 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED); 866 start = failed_start; 867 } else { 868 break; 869 } 870 WARN_ON(start > end); 871 } 872 return err; 873 } 874 EXPORT_SYMBOL(lock_extent); 875 876 int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end, 877 gfp_t mask) 878 { 879 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask); 880 } 881 EXPORT_SYMBOL(unlock_extent); 882 883 /* 884 * helper function to set pages and extents in the tree dirty 885 */ 886 int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end) 887 { 888 unsigned long index = start >> PAGE_CACHE_SHIFT; 889 unsigned long end_index = end >> PAGE_CACHE_SHIFT; 890 struct page *page; 891 892 while (index <= end_index) { 893 page = find_get_page(tree->mapping, index); 894 BUG_ON(!page); 895 __set_page_dirty_nobuffers(page); 896 page_cache_release(page); 897 index++; 898 } 899 set_extent_dirty(tree, start, end, GFP_NOFS); 900 return 0; 901 } 902 EXPORT_SYMBOL(set_range_dirty); 903 904 /* 905 * helper function to set both pages and extents in the tree writeback 906 */ 907 int set_range_writeback(struct extent_map_tree *tree, u64 start, u64 end) 908 { 909 unsigned long index = start >> PAGE_CACHE_SHIFT; 910 unsigned long end_index = end >> PAGE_CACHE_SHIFT; 911 struct page *page; 912 913 while (index <= end_index) { 914 page = find_get_page(tree->mapping, index); 915 BUG_ON(!page); 916 set_page_writeback(page); 917 page_cache_release(page); 918 index++; 919 } 920 set_extent_writeback(tree, start, end, GFP_NOFS); 921 return 0; 922 } 923 EXPORT_SYMBOL(set_range_writeback); 924 925 /* 926 * helper function to lock both pages and extents in the tree. 927 * pages must be locked first. 928 */ 929 int lock_range(struct extent_map_tree *tree, u64 start, u64 end) 930 { 931 unsigned long index = start >> PAGE_CACHE_SHIFT; 932 unsigned long end_index = end >> PAGE_CACHE_SHIFT; 933 struct page *page; 934 int err; 935 936 while (index <= end_index) { 937 page = grab_cache_page(tree->mapping, index); 938 if (!page) { 939 err = -ENOMEM; 940 goto failed; 941 } 942 if (IS_ERR(page)) { 943 err = PTR_ERR(page); 944 goto failed; 945 } 946 index++; 947 } 948 lock_extent(tree, start, end, GFP_NOFS); 949 return 0; 950 951 failed: 952 /* 953 * we failed above in getting the page at 'index', so we undo here 954 * up to but not including the page at 'index' 955 */ 956 end_index = index; 957 index = start >> PAGE_CACHE_SHIFT; 958 while (index < end_index) { 959 page = find_get_page(tree->mapping, index); 960 unlock_page(page); 961 page_cache_release(page); 962 index++; 963 } 964 return err; 965 } 966 EXPORT_SYMBOL(lock_range); 967 968 /* 969 * helper function to unlock both pages and extents in the tree. 970 */ 971 int unlock_range(struct extent_map_tree *tree, u64 start, u64 end) 972 { 973 unsigned long index = start >> PAGE_CACHE_SHIFT; 974 unsigned long end_index = end >> PAGE_CACHE_SHIFT; 975 struct page *page; 976 977 while (index <= end_index) { 978 page = find_get_page(tree->mapping, index); 979 unlock_page(page); 980 page_cache_release(page); 981 index++; 982 } 983 unlock_extent(tree, start, end, GFP_NOFS); 984 return 0; 985 } 986 EXPORT_SYMBOL(unlock_range); 987 988 /* 989 * searches a range in the state tree for a given mask. 990 * If 'filled' == 1, this returns 1 only if ever extent in the tree 991 * has the bits set. Otherwise, 1 is returned if any bit in the 992 * range is found set. 993 */ 994 static int test_range_bit(struct extent_map_tree *tree, u64 start, u64 end, 995 int bits, int filled) 996 { 997 struct extent_state *state = NULL; 998 struct rb_node *node; 999 int bitset = 0; 1000 1001 read_lock_irq(&tree->lock); 1002 node = tree_search(&tree->state, start); 1003 while (node && start <= end) { 1004 state = rb_entry(node, struct extent_state, rb_node); 1005 if (state->start > end) 1006 break; 1007 1008 if (filled && state->start > start) { 1009 bitset = 0; 1010 break; 1011 } 1012 if (state->state & bits) { 1013 bitset = 1; 1014 if (!filled) 1015 break; 1016 } else if (filled) { 1017 bitset = 0; 1018 break; 1019 } 1020 start = state->end + 1; 1021 if (start > end) 1022 break; 1023 node = rb_next(node); 1024 } 1025 read_unlock_irq(&tree->lock); 1026 return bitset; 1027 } 1028 1029 /* 1030 * helper function to set a given page up to date if all the 1031 * extents in the tree for that page are up to date 1032 */ 1033 static int check_page_uptodate(struct extent_map_tree *tree, 1034 struct page *page) 1035 { 1036 u64 start = page->index << PAGE_CACHE_SHIFT; 1037 u64 end = start + PAGE_CACHE_SIZE - 1; 1038 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1)) 1039 SetPageUptodate(page); 1040 return 0; 1041 } 1042 1043 /* 1044 * helper function to unlock a page if all the extents in the tree 1045 * for that page are unlocked 1046 */ 1047 static int check_page_locked(struct extent_map_tree *tree, 1048 struct page *page) 1049 { 1050 u64 start = page->index << PAGE_CACHE_SHIFT; 1051 u64 end = start + PAGE_CACHE_SIZE - 1; 1052 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0)) 1053 unlock_page(page); 1054 return 0; 1055 } 1056 1057 /* 1058 * helper function to end page writeback if all the extents 1059 * in the tree for that page are done with writeback 1060 */ 1061 static int check_page_writeback(struct extent_map_tree *tree, 1062 struct page *page) 1063 { 1064 u64 start = page->index << PAGE_CACHE_SHIFT; 1065 u64 end = start + PAGE_CACHE_SIZE - 1; 1066 if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0)) 1067 end_page_writeback(page); 1068 return 0; 1069 } 1070 1071 /* lots and lots of room for performance fixes in the end_bio funcs */ 1072 1073 /* 1074 * after a writepage IO is done, we need to: 1075 * clear the uptodate bits on error 1076 * clear the writeback bits in the extent tree for this IO 1077 * end_page_writeback if the page has no more pending IO 1078 * 1079 * Scheduling is not allowed, so the extent state tree is expected 1080 * to have one and only one object corresponding to this IO. 1081 */ 1082 static int end_bio_extent_writepage(struct bio *bio, 1083 unsigned int bytes_done, int err) 1084 { 1085 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 1086 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; 1087 struct extent_map_tree *tree = bio->bi_private; 1088 u64 start; 1089 u64 end; 1090 int whole_page; 1091 1092 if (bio->bi_size) 1093 return 1; 1094 1095 do { 1096 struct page *page = bvec->bv_page; 1097 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; 1098 end = start + bvec->bv_len - 1; 1099 1100 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE) 1101 whole_page = 1; 1102 else 1103 whole_page = 0; 1104 1105 if (--bvec >= bio->bi_io_vec) 1106 prefetchw(&bvec->bv_page->flags); 1107 1108 if (!uptodate) { 1109 clear_extent_uptodate(tree, start, end, GFP_ATOMIC); 1110 ClearPageUptodate(page); 1111 SetPageError(page); 1112 } 1113 clear_extent_writeback(tree, start, end, GFP_ATOMIC); 1114 1115 if (whole_page) 1116 end_page_writeback(page); 1117 else 1118 check_page_writeback(tree, page); 1119 } while (bvec >= bio->bi_io_vec); 1120 1121 bio_put(bio); 1122 return 0; 1123 } 1124 1125 /* 1126 * after a readpage IO is done, we need to: 1127 * clear the uptodate bits on error 1128 * set the uptodate bits if things worked 1129 * set the page up to date if all extents in the tree are uptodate 1130 * clear the lock bit in the extent tree 1131 * unlock the page if there are no other extents locked for it 1132 * 1133 * Scheduling is not allowed, so the extent state tree is expected 1134 * to have one and only one object corresponding to this IO. 1135 */ 1136 static int end_bio_extent_readpage(struct bio *bio, 1137 unsigned int bytes_done, int err) 1138 { 1139 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 1140 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; 1141 struct extent_map_tree *tree = bio->bi_private; 1142 u64 start; 1143 u64 end; 1144 int whole_page; 1145 1146 if (bio->bi_size) 1147 return 1; 1148 1149 do { 1150 struct page *page = bvec->bv_page; 1151 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; 1152 end = start + bvec->bv_len - 1; 1153 1154 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE) 1155 whole_page = 1; 1156 else 1157 whole_page = 0; 1158 1159 if (--bvec >= bio->bi_io_vec) 1160 prefetchw(&bvec->bv_page->flags); 1161 1162 if (uptodate) { 1163 set_extent_uptodate(tree, start, end, GFP_ATOMIC); 1164 if (whole_page) 1165 SetPageUptodate(page); 1166 else 1167 check_page_uptodate(tree, page); 1168 } else { 1169 ClearPageUptodate(page); 1170 SetPageError(page); 1171 } 1172 1173 unlock_extent(tree, start, end, GFP_ATOMIC); 1174 1175 if (whole_page) 1176 unlock_page(page); 1177 else 1178 check_page_locked(tree, page); 1179 } while (bvec >= bio->bi_io_vec); 1180 1181 bio_put(bio); 1182 return 0; 1183 } 1184 1185 /* 1186 * IO done from prepare_write is pretty simple, we just unlock 1187 * the structs in the extent tree when done, and set the uptodate bits 1188 * as appropriate. 1189 */ 1190 static int end_bio_extent_preparewrite(struct bio *bio, 1191 unsigned int bytes_done, int err) 1192 { 1193 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 1194 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; 1195 struct extent_map_tree *tree = bio->bi_private; 1196 u64 start; 1197 u64 end; 1198 1199 if (bio->bi_size) 1200 return 1; 1201 1202 do { 1203 struct page *page = bvec->bv_page; 1204 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; 1205 end = start + bvec->bv_len - 1; 1206 1207 if (--bvec >= bio->bi_io_vec) 1208 prefetchw(&bvec->bv_page->flags); 1209 1210 if (uptodate) { 1211 set_extent_uptodate(tree, start, end, GFP_ATOMIC); 1212 } else { 1213 ClearPageUptodate(page); 1214 SetPageError(page); 1215 } 1216 1217 unlock_extent(tree, start, end, GFP_ATOMIC); 1218 1219 } while (bvec >= bio->bi_io_vec); 1220 1221 bio_put(bio); 1222 return 0; 1223 } 1224 1225 static int submit_extent_page(int rw, struct extent_map_tree *tree, 1226 struct page *page, sector_t sector, 1227 size_t size, unsigned long offset, 1228 struct block_device *bdev, 1229 bio_end_io_t end_io_func) 1230 { 1231 struct bio *bio; 1232 int ret = 0; 1233 1234 bio = bio_alloc(GFP_NOIO, 1); 1235 1236 bio->bi_sector = sector; 1237 bio->bi_bdev = bdev; 1238 bio->bi_io_vec[0].bv_page = page; 1239 bio->bi_io_vec[0].bv_len = size; 1240 bio->bi_io_vec[0].bv_offset = offset; 1241 1242 bio->bi_vcnt = 1; 1243 bio->bi_idx = 0; 1244 bio->bi_size = size; 1245 1246 bio->bi_end_io = end_io_func; 1247 bio->bi_private = tree; 1248 1249 bio_get(bio); 1250 submit_bio(rw, bio); 1251 1252 if (bio_flagged(bio, BIO_EOPNOTSUPP)) 1253 ret = -EOPNOTSUPP; 1254 1255 bio_put(bio); 1256 return ret; 1257 } 1258 1259 /* 1260 * basic readpage implementation. Locked extent state structs are inserted 1261 * into the tree that are removed when the IO is done (by the end_io 1262 * handlers) 1263 */ 1264 int extent_read_full_page(struct extent_map_tree *tree, struct page *page, 1265 get_extent_t *get_extent) 1266 { 1267 struct inode *inode = page->mapping->host; 1268 u64 start = page->index << PAGE_CACHE_SHIFT; 1269 u64 page_end = start + PAGE_CACHE_SIZE - 1; 1270 u64 end; 1271 u64 cur = start; 1272 u64 extent_offset; 1273 u64 last_byte = i_size_read(inode); 1274 u64 block_start; 1275 u64 cur_end; 1276 sector_t sector; 1277 struct extent_map *em; 1278 struct block_device *bdev; 1279 int ret; 1280 int nr = 0; 1281 size_t page_offset = 0; 1282 size_t iosize; 1283 size_t blocksize = inode->i_sb->s_blocksize; 1284 1285 if (!PagePrivate(page)) { 1286 SetPagePrivate(page); 1287 set_page_private(page, 1); 1288 page_cache_get(page); 1289 } 1290 1291 end = page_end; 1292 lock_extent(tree, start, end, GFP_NOFS); 1293 1294 while (cur <= end) { 1295 if (cur >= last_byte) { 1296 iosize = PAGE_CACHE_SIZE - page_offset; 1297 zero_user_page(page, page_offset, iosize, KM_USER0); 1298 set_extent_uptodate(tree, cur, cur + iosize - 1, 1299 GFP_NOFS); 1300 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS); 1301 break; 1302 } 1303 em = get_extent(inode, page, page_offset, cur, end, 0); 1304 if (IS_ERR(em) || !em) { 1305 SetPageError(page); 1306 unlock_extent(tree, cur, end, GFP_NOFS); 1307 break; 1308 } 1309 1310 extent_offset = cur - em->start; 1311 BUG_ON(em->end < cur); 1312 BUG_ON(end < cur); 1313 1314 iosize = min(em->end - cur, end - cur) + 1; 1315 cur_end = min(em->end, end); 1316 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1); 1317 sector = (em->block_start + extent_offset) >> 9; 1318 bdev = em->bdev; 1319 block_start = em->block_start; 1320 free_extent_map(em); 1321 em = NULL; 1322 1323 /* we've found a hole, just zero and go on */ 1324 if (block_start == 0) { 1325 zero_user_page(page, page_offset, iosize, KM_USER0); 1326 set_extent_uptodate(tree, cur, cur + iosize - 1, 1327 GFP_NOFS); 1328 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS); 1329 cur = cur + iosize; 1330 page_offset += iosize; 1331 continue; 1332 } 1333 /* the get_extent function already copied into the page */ 1334 if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) { 1335 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS); 1336 cur = cur + iosize; 1337 page_offset += iosize; 1338 continue; 1339 } 1340 1341 ret = submit_extent_page(READ, tree, page, 1342 sector, iosize, page_offset, bdev, 1343 end_bio_extent_readpage); 1344 if (ret) 1345 SetPageError(page); 1346 cur = cur + iosize; 1347 page_offset += iosize; 1348 nr++; 1349 } 1350 if (!nr) { 1351 if (!PageError(page)) 1352 SetPageUptodate(page); 1353 unlock_page(page); 1354 } 1355 return 0; 1356 } 1357 EXPORT_SYMBOL(extent_read_full_page); 1358 1359 /* 1360 * the writepage semantics are similar to regular writepage. extent 1361 * records are inserted to lock ranges in the tree, and as dirty areas 1362 * are found, they are marked writeback. Then the lock bits are removed 1363 * and the end_io handler clears the writeback ranges 1364 */ 1365 int extent_write_full_page(struct extent_map_tree *tree, struct page *page, 1366 get_extent_t *get_extent, 1367 struct writeback_control *wbc) 1368 { 1369 struct inode *inode = page->mapping->host; 1370 u64 start = page->index << PAGE_CACHE_SHIFT; 1371 u64 page_end = start + PAGE_CACHE_SIZE - 1; 1372 u64 end; 1373 u64 cur = start; 1374 u64 extent_offset; 1375 u64 last_byte = i_size_read(inode); 1376 u64 block_start; 1377 sector_t sector; 1378 struct extent_map *em; 1379 struct block_device *bdev; 1380 int ret; 1381 int nr = 0; 1382 size_t page_offset = 0; 1383 size_t iosize; 1384 size_t blocksize; 1385 loff_t i_size = i_size_read(inode); 1386 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT; 1387 1388 if (page->index > end_index) { 1389 clear_extent_dirty(tree, start, page_end, GFP_NOFS); 1390 unlock_page(page); 1391 return 0; 1392 } 1393 1394 if (page->index == end_index) { 1395 size_t offset = i_size & (PAGE_CACHE_SIZE - 1); 1396 zero_user_page(page, offset, 1397 PAGE_CACHE_SIZE - offset, KM_USER0); 1398 } 1399 1400 if (!PagePrivate(page)) { 1401 SetPagePrivate(page); 1402 set_page_private(page, 1); 1403 page_cache_get(page); 1404 } 1405 1406 end = page_end; 1407 lock_extent(tree, start, page_end, GFP_NOFS); 1408 1409 if (last_byte <= start) { 1410 clear_extent_dirty(tree, start, page_end, GFP_NOFS); 1411 goto done; 1412 } 1413 1414 set_extent_uptodate(tree, start, page_end, GFP_NOFS); 1415 blocksize = inode->i_sb->s_blocksize; 1416 1417 while (cur <= end) { 1418 if (cur >= last_byte) { 1419 clear_extent_dirty(tree, cur, page_end, GFP_NOFS); 1420 break; 1421 } 1422 em = get_extent(inode, page, page_offset, cur, end, 1); 1423 if (IS_ERR(em) || !em) { 1424 SetPageError(page); 1425 break; 1426 } 1427 1428 extent_offset = cur - em->start; 1429 BUG_ON(em->end < cur); 1430 BUG_ON(end < cur); 1431 iosize = min(em->end - cur, end - cur) + 1; 1432 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1); 1433 sector = (em->block_start + extent_offset) >> 9; 1434 bdev = em->bdev; 1435 block_start = em->block_start; 1436 free_extent_map(em); 1437 em = NULL; 1438 1439 if (block_start == 0 || block_start == EXTENT_MAP_INLINE) { 1440 clear_extent_dirty(tree, cur, 1441 cur + iosize - 1, GFP_NOFS); 1442 cur = cur + iosize; 1443 page_offset += iosize; 1444 continue; 1445 } 1446 1447 /* leave this out until we have a page_mkwrite call */ 1448 if (0 && !test_range_bit(tree, cur, cur + iosize - 1, 1449 EXTENT_DIRTY, 0)) { 1450 cur = cur + iosize; 1451 page_offset += iosize; 1452 continue; 1453 } 1454 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS); 1455 set_range_writeback(tree, cur, cur + iosize - 1); 1456 ret = submit_extent_page(WRITE, tree, page, 1457 sector, iosize, page_offset, bdev, 1458 end_bio_extent_writepage); 1459 if (ret) 1460 SetPageError(page); 1461 cur = cur + iosize; 1462 page_offset += iosize; 1463 nr++; 1464 } 1465 done: 1466 WARN_ON(test_range_bit(tree, start, page_end, EXTENT_DIRTY, 0)); 1467 unlock_extent(tree, start, page_end, GFP_NOFS); 1468 unlock_page(page); 1469 return 0; 1470 } 1471 EXPORT_SYMBOL(extent_write_full_page); 1472 1473 /* 1474 * basic invalidatepage code, this waits on any locked or writeback 1475 * ranges corresponding to the page, and then deletes any extent state 1476 * records from the tree 1477 */ 1478 int extent_invalidatepage(struct extent_map_tree *tree, 1479 struct page *page, unsigned long offset) 1480 { 1481 u64 start = (page->index << PAGE_CACHE_SHIFT); 1482 u64 end = start + PAGE_CACHE_SIZE - 1; 1483 size_t blocksize = page->mapping->host->i_sb->s_blocksize; 1484 1485 start += (offset + blocksize -1) & ~(blocksize - 1); 1486 if (start > end) 1487 return 0; 1488 1489 lock_extent(tree, start, end, GFP_NOFS); 1490 wait_on_extent_writeback(tree, start, end); 1491 clear_extent_bit(tree, start, end, EXTENT_LOCKED | EXTENT_DIRTY, 1492 1, 1, GFP_NOFS); 1493 return 0; 1494 } 1495 EXPORT_SYMBOL(extent_invalidatepage); 1496 1497 /* 1498 * simple commit_write call, set_range_dirty is used to mark both 1499 * the pages and the extent records as dirty 1500 */ 1501 int extent_commit_write(struct extent_map_tree *tree, 1502 struct inode *inode, struct page *page, 1503 unsigned from, unsigned to) 1504 { 1505 loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; 1506 1507 if (!PagePrivate(page)) { 1508 SetPagePrivate(page); 1509 set_page_private(page, 1); 1510 page_cache_get(page); 1511 } 1512 1513 set_page_dirty(page); 1514 1515 if (pos > inode->i_size) { 1516 i_size_write(inode, pos); 1517 mark_inode_dirty(inode); 1518 } 1519 return 0; 1520 } 1521 EXPORT_SYMBOL(extent_commit_write); 1522 1523 int extent_prepare_write(struct extent_map_tree *tree, 1524 struct inode *inode, struct page *page, 1525 unsigned from, unsigned to, get_extent_t *get_extent) 1526 { 1527 u64 page_start = page->index << PAGE_CACHE_SHIFT; 1528 u64 page_end = page_start + PAGE_CACHE_SIZE - 1; 1529 u64 block_start; 1530 u64 orig_block_start; 1531 u64 block_end; 1532 u64 cur_end; 1533 struct extent_map *em; 1534 unsigned blocksize = 1 << inode->i_blkbits; 1535 size_t page_offset = 0; 1536 size_t block_off_start; 1537 size_t block_off_end; 1538 int err = 0; 1539 int iocount = 0; 1540 int ret = 0; 1541 int isnew; 1542 1543 if (!PagePrivate(page)) { 1544 SetPagePrivate(page); 1545 set_page_private(page, 1); 1546 page_cache_get(page); 1547 } 1548 block_start = (page_start + from) & ~((u64)blocksize - 1); 1549 block_end = (page_start + to - 1) | (blocksize - 1); 1550 orig_block_start = block_start; 1551 1552 lock_extent(tree, page_start, page_end, GFP_NOFS); 1553 while(block_start <= block_end) { 1554 em = get_extent(inode, page, page_offset, block_start, 1555 block_end, 1); 1556 if (IS_ERR(em) || !em) { 1557 goto err; 1558 } 1559 cur_end = min(block_end, em->end); 1560 block_off_start = block_start & (PAGE_CACHE_SIZE - 1); 1561 block_off_end = block_off_start + blocksize; 1562 isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS); 1563 1564 if (!PageUptodate(page) && isnew && 1565 (block_off_end > to || block_off_start < from)) { 1566 void *kaddr; 1567 1568 kaddr = kmap_atomic(page, KM_USER0); 1569 if (block_off_end > to) 1570 memset(kaddr + to, 0, block_off_end - to); 1571 if (block_off_start < from) 1572 memset(kaddr + block_off_start, 0, 1573 from - block_off_start); 1574 flush_dcache_page(page); 1575 kunmap_atomic(kaddr, KM_USER0); 1576 } 1577 if (!isnew && !PageUptodate(page) && 1578 (block_off_end > to || block_off_start < from) && 1579 !test_range_bit(tree, block_start, cur_end, 1580 EXTENT_UPTODATE, 1)) { 1581 u64 sector; 1582 u64 extent_offset = block_start - em->start; 1583 size_t iosize; 1584 sector = (em->block_start + extent_offset) >> 9; 1585 iosize = (cur_end - block_start + blocksize - 1) & 1586 ~((u64)blocksize - 1); 1587 /* 1588 * we've already got the extent locked, but we 1589 * need to split the state such that our end_bio 1590 * handler can clear the lock. 1591 */ 1592 set_extent_bit(tree, block_start, 1593 block_start + iosize - 1, 1594 EXTENT_LOCKED, 0, NULL, GFP_NOFS); 1595 ret = submit_extent_page(READ, tree, page, 1596 sector, iosize, page_offset, em->bdev, 1597 end_bio_extent_preparewrite); 1598 iocount++; 1599 block_start = block_start + iosize; 1600 } else { 1601 set_extent_uptodate(tree, block_start, cur_end, 1602 GFP_NOFS); 1603 unlock_extent(tree, block_start, cur_end, GFP_NOFS); 1604 block_start = cur_end + 1; 1605 } 1606 page_offset = block_start & (PAGE_CACHE_SIZE - 1); 1607 free_extent_map(em); 1608 } 1609 if (iocount) { 1610 wait_extent_bit(tree, orig_block_start, 1611 block_end, EXTENT_LOCKED); 1612 } 1613 check_page_uptodate(tree, page); 1614 err: 1615 /* FIXME, zero out newly allocated blocks on error */ 1616 return err; 1617 } 1618 EXPORT_SYMBOL(extent_prepare_write); 1619 1620 /* 1621 * a helper for releasepage. As long as there are no locked extents 1622 * in the range corresponding to the page, both state records and extent 1623 * map records are removed 1624 */ 1625 int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page) 1626 { 1627 struct extent_map *em; 1628 u64 start = page->index << PAGE_CACHE_SHIFT; 1629 u64 end = start + PAGE_CACHE_SIZE - 1; 1630 u64 orig_start = start; 1631 1632 while (start <= end) { 1633 em = lookup_extent_mapping(tree, start, end); 1634 if (!em || IS_ERR(em)) 1635 break; 1636 if (test_range_bit(tree, em->start, em->end, 1637 EXTENT_LOCKED, 0)) { 1638 free_extent_map(em); 1639 start = em->end + 1; 1640 printk("range still locked %Lu %Lu\n", em->start, em->end); 1641 break; 1642 } 1643 remove_extent_mapping(tree, em); 1644 start = em->end + 1; 1645 /* once for the rb tree */ 1646 free_extent_map(em); 1647 /* once for us */ 1648 free_extent_map(em); 1649 } 1650 WARN_ON(test_range_bit(tree, orig_start, end, EXTENT_WRITEBACK, 0)); 1651 clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE, 1652 1, 1, GFP_NOFS); 1653 return 1; 1654 } 1655 EXPORT_SYMBOL(try_release_extent_mapping); 1656 1657