SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/btrfs/extent_io.c

   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 <linux/swap.h>
  12 #include <linux/version.h>
  13 #include <linux/writeback.h>
  14 #include <linux/pagevec.h>
  15 #include "extent_io.h"
  16 #include "extent_map.h"
  17
  18 /* temporary define until extent_map moves out of btrfs */
  19 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
  20                                        unsigned long extra_flags,
  21                                        void (*ctor)(void *, struct kmem_cache *,
  22                                                     unsigned long));
  23
  24 static struct kmem_cache *extent_state_cache;
  25 static struct kmem_cache *extent_buffer_cache;
  26
  27 static LIST_HEAD(buffers);
  28 static LIST_HEAD(states);
  29 static spinlock_t leak_lock = SPIN_LOCK_UNLOCKED;
  30
  31 #define BUFFER_LRU_MAX 64
  32
  33 struct tree_entry {
  34         u64 start;
  35         u64 end;
  36         struct rb_node rb_node;
  37 };
  38
  39 struct extent_page_data {
  40         struct bio *bio;
  41         struct extent_io_tree *tree;
  42         get_extent_t *get_extent;
  43 };
  44
  45 int __init extent_io_init(void)
  46 {
  47         extent_state_cache = btrfs_cache_create("extent_state",
  48                                             sizeof(struct extent_state), 0,
  49                                             NULL);
  50         if (!extent_state_cache)
  51                 return -ENOMEM;
  52
  53         extent_buffer_cache = btrfs_cache_create("extent_buffers",
  54                                             sizeof(struct extent_buffer), 0,
  55                                             NULL);
  56         if (!extent_buffer_cache)
  57                 goto free_state_cache;
  58         return 0;
  59
  60 free_state_cache:
  61         kmem_cache_destroy(extent_state_cache);
  62         return -ENOMEM;
  63 }
  64
  65 void extent_io_exit(void)
  66 {
  67         struct extent_state *state;
  68         struct extent_buffer *eb;
  69
  70         while (!list_empty(&states)) {
  71                 state = list_entry(states.next, struct extent_state, leak_list);
  72                 printk("state leak: start %Lu end %Lu state %lu in tree %p refs %d\n", state->start, state->end, state->state, state->tree, atomic_read(&state->refs));
  73                 list_del(&state->leak_list);
  74                 kmem_cache_free(extent_state_cache, state);
  75
  76         }
  77
  78         while (!list_empty(&buffers)) {
  79                 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
  80                 printk("buffer leak start %Lu len %lu refs %d\n", eb->start, eb->len, atomic_read(&eb->refs));
  81                 list_del(&eb->leak_list);
  82                 kmem_cache_free(extent_buffer_cache, eb);
  83         }
  84         if (extent_state_cache)
  85                 kmem_cache_destroy(extent_state_cache);
  86         if (extent_buffer_cache)
  87                 kmem_cache_destroy(extent_buffer_cache);
  88 }
  89
  90 void extent_io_tree_init(struct extent_io_tree *tree,
  91                           struct address_space *mapping, gfp_t mask)
  92 {
  93         tree->state.rb_node = NULL;
  94         tree->buffer.rb_node = NULL;
  95         tree->ops = NULL;
  96         tree->dirty_bytes = 0;
  97         spin_lock_init(&tree->lock);
  98         spin_lock_init(&tree->buffer_lock);
  99         tree->mapping = mapping;
 100 }
 101 EXPORT_SYMBOL(extent_io_tree_init);
 102
 103 struct extent_state *alloc_extent_state(gfp_t mask)
 104 {
 105         struct extent_state *state;
 106         unsigned long flags;
 107
 108         state = kmem_cache_alloc(extent_state_cache, mask);
 109         if (!state)
 110                 return state;
 111         state->state = 0;
 112         state->private = 0;
 113         state->tree = NULL;
 114         spin_lock_irqsave(&leak_lock, flags);
 115         list_add(&state->leak_list, &states);
 116         spin_unlock_irqrestore(&leak_lock, flags);
 117
 118         atomic_set(&state->refs, 1);
 119         init_waitqueue_head(&state->wq);
 120         return state;
 121 }
 122 EXPORT_SYMBOL(alloc_extent_state);
 123
 124 void free_extent_state(struct extent_state *state)
 125 {
 126         if (!state)
 127                 return;
 128         if (atomic_dec_and_test(&state->refs)) {
 129                 unsigned long flags;
 130                 WARN_ON(state->tree);
 131                 spin_lock_irqsave(&leak_lock, flags);
 132                 list_del(&state->leak_list);
 133                 spin_unlock_irqrestore(&leak_lock, flags);
 134                 kmem_cache_free(extent_state_cache, state);
 135         }
 136 }
 137 EXPORT_SYMBOL(free_extent_state);
 138
 139 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
 140                                    struct rb_node *node)
 141 {
 142         struct rb_node ** p = &root->rb_node;
 143         struct rb_node * parent = NULL;
 144         struct tree_entry *entry;
 145
 146         while(*p) {
 147                 parent = *p;
 148                 entry = rb_entry(parent, struct tree_entry, rb_node);
 149
 150                 if (offset < entry->start)
 151                         p = &(*p)->rb_left;
 152                 else if (offset > entry->end)
 153                         p = &(*p)->rb_right;
 154                 else
 155                         return parent;
 156         }
 157
 158         entry = rb_entry(node, struct tree_entry, rb_node);
 159         rb_link_node(node, parent, p);
 160         rb_insert_color(node, root);
 161         return NULL;
 162 }
 163
 164 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
 165                                      struct rb_node **prev_ret,
 166                                      struct rb_node **next_ret)
 167 {
 168         struct rb_root *root = &tree->state;
 169         struct rb_node * n = root->rb_node;
 170         struct rb_node *prev = NULL;
 171         struct rb_node *orig_prev = NULL;
 172         struct tree_entry *entry;
 173         struct tree_entry *prev_entry = NULL;
 174
 175         while(n) {
 176                 entry = rb_entry(n, struct tree_entry, rb_node);
 177                 prev = n;
 178                 prev_entry = entry;
 179
 180                 if (offset < entry->start)
 181                         n = n->rb_left;
 182                 else if (offset > entry->end)
 183                         n = n->rb_right;
 184                 else {
 185                         return n;
 186                 }
 187         }
 188
 189         if (prev_ret) {
 190                 orig_prev = prev;
 191                 while(prev && offset > prev_entry->end) {
 192                         prev = rb_next(prev);
 193                         prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 194                 }
 195                 *prev_ret = prev;
 196                 prev = orig_prev;
 197         }
 198
 199         if (next_ret) {
 200                 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 201                 while(prev && offset < prev_entry->start) {
 202                         prev = rb_prev(prev);
 203                         prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 204                 }
 205                 *next_ret = prev;
 206         }
 207         return NULL;
 208 }
 209
 210 static inline struct rb_node *tree_search(struct extent_io_tree *tree,
 211                                           u64 offset)
 212 {
 213         struct rb_node *prev = NULL;
 214         struct rb_node *ret;
 215
 216         ret = __etree_search(tree, offset, &prev, NULL);
 217         if (!ret) {
 218                 return prev;
 219         }
 220         return ret;
 221 }
 222
 223 static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree,
 224                                           u64 offset, struct rb_node *node)
 225 {
 226         struct rb_root *root = &tree->buffer;
 227         struct rb_node ** p = &root->rb_node;
 228         struct rb_node * parent = NULL;
 229         struct extent_buffer *eb;
 230
 231         while(*p) {
 232                 parent = *p;
 233                 eb = rb_entry(parent, struct extent_buffer, rb_node);
 234
 235                 if (offset < eb->start)
 236                         p = &(*p)->rb_left;
 237                 else if (offset > eb->start)
 238                         p = &(*p)->rb_right;
 239                 else
 240                         return eb;
 241         }
 242
 243         rb_link_node(node, parent, p);
 244         rb_insert_color(node, root);
 245         return NULL;
 246 }
 247
 248 static struct extent_buffer *buffer_search(struct extent_io_tree *tree,
 249                                            u64 offset)
 250 {
 251         struct rb_root *root = &tree->buffer;
 252         struct rb_node * n = root->rb_node;
 253         struct extent_buffer *eb;
 254
 255         while(n) {
 256                 eb = rb_entry(n, struct extent_buffer, rb_node);
 257                 if (offset < eb->start)
 258                         n = n->rb_left;
 259                 else if (offset > eb->start)
 260                         n = n->rb_right;
 261                 else
 262                         return eb;
 263         }
 264         return NULL;
 265 }
 266
 267 /*
 268  * utility function to look for merge candidates inside a given range.
 269  * Any extents with matching state are merged together into a single
 270  * extent in the tree.  Extents with EXTENT_IO in their state field
 271  * are not merged because the end_io handlers need to be able to do
 272  * operations on them without sleeping (or doing allocations/splits).
 273  *
 274  * This should be called with the tree lock held.
 275  */
 276 static int merge_state(struct extent_io_tree *tree,
 277                        struct extent_state *state)
 278 {
 279         struct extent_state *other;
 280         struct rb_node *other_node;
 281
 282         if (state->state & EXTENT_IOBITS)
 283                 return 0;
 284
 285         other_node = rb_prev(&state->rb_node);
 286         if (other_node) {
 287                 other = rb_entry(other_node, struct extent_state, rb_node);
 288                 if (other->end == state->start - 1 &&
 289                     other->state == state->state) {
 290                         state->start = other->start;
 291                         other->tree = NULL;
 292                         rb_erase(&other->rb_node, &tree->state);
 293                         free_extent_state(other);
 294                 }
 295         }
 296         other_node = rb_next(&state->rb_node);
 297         if (other_node) {
 298                 other = rb_entry(other_node, struct extent_state, rb_node);
 299                 if (other->start == state->end + 1 &&
 300                     other->state == state->state) {
 301                         other->start = state->start;
 302                         state->tree = NULL;
 303                         rb_erase(&state->rb_node, &tree->state);
 304                         free_extent_state(state);
 305                 }
 306         }
 307         return 0;
 308 }
 309
 310 static void set_state_cb(struct extent_io_tree *tree,
 311                          struct extent_state *state,
 312                          unsigned long bits)
 313 {
 314         if (tree->ops && tree->ops->set_bit_hook) {
 315                 tree->ops->set_bit_hook(tree->mapping->host, state->start,
 316                                         state->end, state->state, bits);
 317         }
 318 }
 319
 320 static void clear_state_cb(struct extent_io_tree *tree,
 321                            struct extent_state *state,
 322                            unsigned long bits)
 323 {
 324         if (tree->ops && tree->ops->set_bit_hook) {
 325                 tree->ops->clear_bit_hook(tree->mapping->host, state->start,
 326                                           state->end, state->state, bits);
 327         }
 328 }
 329
 330 /*
 331  * insert an extent_state struct into the tree.  'bits' are set on the
 332  * struct before it is inserted.
 333  *
 334  * This may return -EEXIST if the extent is already there, in which case the
 335  * state struct is freed.
 336  *
 337  * The tree lock is not taken internally.  This is a utility function and
 338  * probably isn't what you want to call (see set/clear_extent_bit).
 339  */
 340 static int insert_state(struct extent_io_tree *tree,
 341                         struct extent_state *state, u64 start, u64 end,
 342                         int bits)
 343 {
 344         struct rb_node *node;
 345
 346         if (end < start) {
 347                 printk("end < start %Lu %Lu\n", end, start);
 348                 WARN_ON(1);
 349         }
 350         if (bits & EXTENT_DIRTY)
 351                 tree->dirty_bytes += end - start + 1;
 352         set_state_cb(tree, state, bits);
 353         state->state |= bits;
 354         state->start = start;
 355         state->end = end;
 356         node = tree_insert(&tree->state, end, &state->rb_node);
 357         if (node) {
 358                 struct extent_state *found;
 359                 found = rb_entry(node, struct extent_state, rb_node);
 360                 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
 361                 free_extent_state(state);
 362                 return -EEXIST;
 363         }
 364         state->tree = tree;
 365         merge_state(tree, state);
 366         return 0;
 367 }
 368
 369 /*
 370  * split a given extent state struct in two, inserting the preallocated
 371  * struct 'prealloc' as the newly created second half.  'split' indicates an
 372  * offset inside 'orig' where it should be split.
 373  *
 374  * Before calling,
 375  * the tree has 'orig' at [orig->start, orig->end].  After calling, there
 376  * are two extent state structs in the tree:
 377  * prealloc: [orig->start, split - 1]
 378  * orig: [ split, orig->end ]
 379  *
 380  * The tree locks are not taken by this function. They need to be held
 381  * by the caller.
 382  */
 383 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 384                        struct extent_state *prealloc, u64 split)
 385 {
 386         struct rb_node *node;
 387         prealloc->start = orig->start;
 388         prealloc->end = split - 1;
 389         prealloc->state = orig->state;
 390         orig->start = split;
 391
 392         node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
 393         if (node) {
 394                 struct extent_state *found;
 395                 found = rb_entry(node, struct extent_state, rb_node);
 396                 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
 397                 free_extent_state(prealloc);
 398                 return -EEXIST;
 399         }
 400         prealloc->tree = tree;
 401         return 0;
 402 }
 403
 404 /*
 405  * utility function to clear some bits in an extent state struct.
 406  * it will optionally wake up any one waiting on this state (wake == 1), or
 407  * forcibly remove the state from the tree (delete == 1).
 408  *
 409  * If no bits are set on the state struct after clearing things, the
 410  * struct is freed and removed from the tree
 411  */
 412 static int clear_state_bit(struct extent_io_tree *tree,
 413                             struct extent_state *state, int bits, int wake,
 414                             int delete)
 415 {
 416         int ret = state->state & bits;
 417
 418         if ((bits & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
 419                 u64 range = state->end - state->start + 1;
 420                 WARN_ON(range > tree->dirty_bytes);
 421                 tree->dirty_bytes -= range;
 422         }
 423         clear_state_cb(tree, state, bits);
 424         state->state &= ~bits;
 425         if (wake)
 426                 wake_up(&state->wq);
 427         if (delete || state->state == 0) {
 428                 if (state->tree) {
 429                         clear_state_cb(tree, state, state->state);
 430                         rb_erase(&state->rb_node, &tree->state);
 431                         state->tree = NULL;
 432                         free_extent_state(state);
 433                 } else {
 434                         WARN_ON(1);
 435                 }
 436         } else {
 437                 merge_state(tree, state);
 438         }
 439         return ret;
 440 }
 441
 442 /*
 443  * clear some bits on a range in the tree.  This may require splitting
 444  * or inserting elements in the tree, so the gfp mask is used to
 445  * indicate which allocations or sleeping are allowed.
 446  *
 447  * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
 448  * the given range from the tree regardless of state (ie for truncate).
 449  *
 450  * the range [start, end] is inclusive.
 451  *
 452  * This takes the tree lock, and returns < 0 on error, > 0 if any of the
 453  * bits were already set, or zero if none of the bits were already set.
 454  */
 455 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 456                      int bits, int wake, int delete, gfp_t mask)
 457 {
 458         struct extent_state *state;
 459         struct extent_state *prealloc = NULL;
 460         struct rb_node *node;
 461         unsigned long flags;
 462         int err;
 463         int set = 0;
 464
 465 again:
 466         if (!prealloc && (mask & __GFP_WAIT)) {
 467                 prealloc = alloc_extent_state(mask);
 468                 if (!prealloc)
 469                         return -ENOMEM;
 470         }
 471
 472         spin_lock_irqsave(&tree->lock, flags);
 473         /*
 474          * this search will find the extents that end after
 475          * our range starts
 476          */
 477         node = tree_search(tree, start);
 478         if (!node)
 479                 goto out;
 480         state = rb_entry(node, struct extent_state, rb_node);
 481         if (state->start > end)
 482                 goto out;
 483         WARN_ON(state->end < start);
 484
 485         /*
 486          *     | ---- desired range ---- |
 487          *  | state | or
 488          *  | ------------- state -------------- |
 489          *
 490          * We need to split the extent we found, and may flip
 491          * bits on second half.
 492          *
 493          * If the extent we found extends past our range, we
 494          * just split and search again.  It'll get split again
 495          * the next time though.
 496          *
 497          * If the extent we found is inside our range, we clear
 498          * the desired bit on it.
 499          */
 500
 501         if (state->start < start) {
 502                 if (!prealloc)
 503                         prealloc = alloc_extent_state(GFP_ATOMIC);
 504                 err = split_state(tree, state, prealloc, start);
 505                 BUG_ON(err == -EEXIST);
 506                 prealloc = NULL;
 507                 if (err)
 508                         goto out;
 509                 if (state->end <= end) {
 510                         start = state->end + 1;
 511                         set |= clear_state_bit(tree, state, bits,
 512                                         wake, delete);
 513                 } else {
 514                         start = state->start;
 515                 }
 516                 goto search_again;
 517         }
 518         /*
 519          * | ---- desired range ---- |
 520          *                        | state |
 521          * We need to split the extent, and clear the bit
 522          * on the first half
 523          */
 524         if (state->start <= end && state->end > end) {
 525                 if (!prealloc)
 526                         prealloc = alloc_extent_state(GFP_ATOMIC);
 527                 err = split_state(tree, state, prealloc, end + 1);
 528                 BUG_ON(err == -EEXIST);
 529
 530                 if (wake)
 531                         wake_up(&state->wq);
 532                 set |= clear_state_bit(tree, prealloc, bits,
 533                                        wake, delete);
 534                 prealloc = NULL;
 535                 goto out;
 536         }
 537
 538         start = state->end + 1;
 539         set |= clear_state_bit(tree, state, bits, wake, delete);
 540         goto search_again;
 541
 542 out:
 543         spin_unlock_irqrestore(&tree->lock, flags);
 544         if (prealloc)
 545                 free_extent_state(prealloc);
 546
 547         return set;
 548
 549 search_again:
 550         if (start > end)
 551                 goto out;
 552         spin_unlock_irqrestore(&tree->lock, flags);
 553         if (mask & __GFP_WAIT)
 554                 cond_resched();
 555         goto again;
 556 }
 557 EXPORT_SYMBOL(clear_extent_bit);
 558
 559 static int wait_on_state(struct extent_io_tree *tree,
 560                          struct extent_state *state)
 561 {
 562         DEFINE_WAIT(wait);
 563         prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
 564         spin_unlock_irq(&tree->lock);
 565         schedule();
 566         spin_lock_irq(&tree->lock);
 567         finish_wait(&state->wq, &wait);
 568         return 0;
 569 }
 570
 571 /*
 572  * waits for one or more bits to clear on a range in the state tree.
 573  * The range [start, end] is inclusive.
 574  * The tree lock is taken by this function
 575  */
 576 int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
 577 {
 578         struct extent_state *state;
 579         struct rb_node *node;
 580
 581         spin_lock_irq(&tree->lock);
 582 again:
 583         while (1) {
 584                 /*
 585                  * this search will find all the extents that end after
 586                  * our range starts
 587                  */
 588                 node = tree_search(tree, start);
 589                 if (!node)
 590                         break;
 591
 592                 state = rb_entry(node, struct extent_state, rb_node);
 593
 594                 if (state->start > end)
 595                         goto out;
 596
 597                 if (state->state & bits) {
 598                         start = state->start;
 599                         atomic_inc(&state->refs);
 600                         wait_on_state(tree, state);
 601                         free_extent_state(state);
 602                         goto again;
 603                 }
 604                 start = state->end + 1;
 605
 606                 if (start > end)
 607                         break;
 608
 609                 if (need_resched()) {
 610                         spin_unlock_irq(&tree->lock);
 611                         cond_resched();
 612                         spin_lock_irq(&tree->lock);
 613                 }
 614         }
 615 out:
 616         spin_unlock_irq(&tree->lock);
 617         return 0;
 618 }
 619 EXPORT_SYMBOL(wait_extent_bit);
 620
 621 static void set_state_bits(struct extent_io_tree *tree,
 622                            struct extent_state *state,
 623                            int bits)
 624 {
 625         if ((bits & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
 626                 u64 range = state->end - state->start + 1;
 627                 tree->dirty_bytes += range;
 628         }
 629         set_state_cb(tree, state, bits);
 630         state->state |= bits;
 631 }
 632
 633 /*
 634  * set some bits on a range in the tree.  This may require allocations
 635  * or sleeping, so the gfp mask is used to indicate what is allowed.
 636  *
 637  * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
 638  * range already has the desired bits set.  The start of the existing
 639  * range is returned in failed_start in this case.
 640  *
 641  * [start, end] is inclusive
 642  * This takes the tree lock.
 643  */
 644 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits,
 645                    int exclusive, u64 *failed_start, gfp_t mask)
 646 {
 647         struct extent_state *state;
 648         struct extent_state *prealloc = NULL;
 649         struct rb_node *node;
 650         unsigned long flags;
 651         int err = 0;
 652         int set;
 653         u64 last_start;
 654         u64 last_end;
 655 again:
 656         if (!prealloc && (mask & __GFP_WAIT)) {
 657                 prealloc = alloc_extent_state(mask);
 658                 if (!prealloc)
 659                         return -ENOMEM;
 660         }
 661
 662         spin_lock_irqsave(&tree->lock, flags);
 663         /*
 664          * this search will find all the extents that end after
 665          * our range starts.
 666          */
 667         node = tree_search(tree, start);
 668         if (!node) {
 669                 err = insert_state(tree, prealloc, start, end, bits);
 670                 prealloc = NULL;
 671                 BUG_ON(err == -EEXIST);
 672                 goto out;
 673         }
 674
 675         state = rb_entry(node, struct extent_state, rb_node);
 676         last_start = state->start;
 677         last_end = state->end;
 678
 679         /*
 680          * | ---- desired range ---- |
 681          * | state |
 682          *
 683          * Just lock what we found and keep going
 684          */
 685         if (state->start == start && state->end <= end) {
 686                 set = state->state & bits;
 687                 if (set && exclusive) {
 688                         *failed_start = state->start;
 689                         err = -EEXIST;
 690                         goto out;
 691                 }
 692                 set_state_bits(tree, state, bits);
 693                 start = state->end + 1;
 694                 merge_state(tree, state);
 695                 goto search_again;
 696         }
 697
 698         /*
 699          *     | ---- desired range ---- |
 700          * | state |
 701          *   or
 702          * | ------------- state -------------- |
 703          *
 704          * We need to split the extent we found, and may flip bits on
 705          * second half.
 706          *
 707          * If the extent we found extends past our
 708          * range, we just split and search again.  It'll get split
 709          * again the next time though.
 710          *
 711          * If the extent we found is inside our range, we set the
 712          * desired bit on it.
 713          */
 714         if (state->start < start) {
 715                 set = state->state & bits;
 716                 if (exclusive && set) {
 717                         *failed_start = start;
 718                         err = -EEXIST;
 719                         goto out;
 720                 }
 721                 err = split_state(tree, state, prealloc, start);
 722                 BUG_ON(err == -EEXIST);
 723                 prealloc = NULL;
 724                 if (err)
 725                         goto out;
 726                 if (state->end <= end) {
 727                         set_state_bits(tree, state, bits);
 728                         start = state->end + 1;
 729                         merge_state(tree, state);
 730                 } else {
 731                         start = state->start;
 732                 }
 733                 goto search_again;
 734         }
 735         /*
 736          * | ---- desired range ---- |
 737          *     | state | or               | state |
 738          *
 739          * There's a hole, we need to insert something in it and
 740          * ignore the extent we found.
 741          */
 742         if (state->start > start) {
 743                 u64 this_end;
 744                 if (end < last_start)
 745                         this_end = end;
 746                 else
 747                         this_end = last_start -1;
 748                 err = insert_state(tree, prealloc, start, this_end,
 749                                    bits);
 750                 prealloc = NULL;
 751                 BUG_ON(err == -EEXIST);
 752                 if (err)
 753                         goto out;
 754                 start = this_end + 1;
 755                 goto search_again;
 756         }
 757         /*
 758          * | ---- desired range ---- |
 759          *                        | state |
 760          * We need to split the extent, and set the bit
 761          * on the first half
 762          */
 763         if (state->start <= end && state->end > end) {
 764                 set = state->state & bits;
 765                 if (exclusive && set) {
 766                         *failed_start = start;
 767                         err = -EEXIST;
 768                         goto out;
 769                 }
 770                 err = split_state(tree, state, prealloc, end + 1);
 771                 BUG_ON(err == -EEXIST);
 772
 773                 set_state_bits(tree, prealloc, bits);
 774                 merge_state(tree, prealloc);
 775                 prealloc = NULL;
 776                 goto out;
 777         }
 778
 779         goto search_again;
 780
 781 out:
 782         spin_unlock_irqrestore(&tree->lock, flags);
 783         if (prealloc)
 784                 free_extent_state(prealloc);
 785
 786         return err;
 787
 788 search_again:
 789         if (start > end)
 790                 goto out;
 791         spin_unlock_irqrestore(&tree->lock, flags);
 792         if (mask & __GFP_WAIT)
 793                 cond_resched();
 794         goto again;
 795 }
 796 EXPORT_SYMBOL(set_extent_bit);
 797
 798 /* wrappers around set/clear extent bit */
 799 int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
 800                      gfp_t mask)
 801 {
 802         return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
 803                               mask);
 804 }
 805 EXPORT_SYMBOL(set_extent_dirty);
 806
 807 int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
 808                        gfp_t mask)
 809 {
 810         return set_extent_bit(tree, start, end, EXTENT_ORDERED, 0, NULL, mask);
 811 }
 812 EXPORT_SYMBOL(set_extent_ordered);
 813
 814 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 815                     int bits, gfp_t mask)
 816 {
 817         return set_extent_bit(tree, start, end, bits, 0, NULL,
 818                               mask);
 819 }
 820 EXPORT_SYMBOL(set_extent_bits);
 821
 822 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 823                       int bits, gfp_t mask)
 824 {
 825         return clear_extent_bit(tree, start, end, bits, 0, 0, mask);
 826 }
 827 EXPORT_SYMBOL(clear_extent_bits);
 828
 829 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
 830                      gfp_t mask)
 831 {
 832         return set_extent_bit(tree, start, end,
 833                               EXTENT_DELALLOC | EXTENT_DIRTY,
 834                               0, NULL, mask);
 835 }
 836 EXPORT_SYMBOL(set_extent_delalloc);
 837
 838 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
 839                        gfp_t mask)
 840 {
 841         return clear_extent_bit(tree, start, end,
 842                                 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, mask);
 843 }
 844 EXPORT_SYMBOL(clear_extent_dirty);
 845
 846 int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
 847                          gfp_t mask)
 848 {
 849         return clear_extent_bit(tree, start, end, EXTENT_ORDERED, 1, 0, mask);
 850 }
 851 EXPORT_SYMBOL(clear_extent_ordered);
 852
 853 int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
 854                      gfp_t mask)
 855 {
 856         return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
 857                               mask);
 858 }
 859 EXPORT_SYMBOL(set_extent_new);
 860
 861 int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
 862                        gfp_t mask)
 863 {
 864         return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
 865 }
 866 EXPORT_SYMBOL(clear_extent_new);
 867
 868 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
 869                         gfp_t mask)
 870 {
 871         return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
 872                               mask);
 873 }
 874 EXPORT_SYMBOL(set_extent_uptodate);
 875
 876 int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
 877                           gfp_t mask)
 878 {
 879         return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
 880 }
 881 EXPORT_SYMBOL(clear_extent_uptodate);
 882
 883 int set_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
 884                          gfp_t mask)
 885 {
 886         return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
 887                               0, NULL, mask);
 888 }
 889 EXPORT_SYMBOL(set_extent_writeback);
 890
 891 int clear_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
 892                            gfp_t mask)
 893 {
 894         return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
 895 }
 896 EXPORT_SYMBOL(clear_extent_writeback);
 897
 898 int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
 899 {
 900         return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
 901 }
 902 EXPORT_SYMBOL(wait_on_extent_writeback);
 903
 904 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
 905 {
 906         int err;
 907         u64 failed_start;
 908         while (1) {
 909                 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
 910                                      &failed_start, mask);
 911                 if (err == -EEXIST && (mask & __GFP_WAIT)) {
 912                         wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
 913                         start = failed_start;
 914                 } else {
 915                         break;
 916                 }
 917                 WARN_ON(start > end);
 918         }
 919         return err;
 920 }
 921 EXPORT_SYMBOL(lock_extent);
 922
 923 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
 924                   gfp_t mask)
 925 {
 926         return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
 927 }
 928 EXPORT_SYMBOL(unlock_extent);
 929
 930 /*
 931  * helper function to set pages and extents in the tree dirty
 932  */
 933 int set_range_dirty(struct extent_io_tree *tree, u64 start, u64 end)
 934 {
 935         unsigned long index = start >> PAGE_CACHE_SHIFT;
 936         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
 937         struct page *page;
 938
 939         while (index <= end_index) {
 940                 page = find_get_page(tree->mapping, index);
 941                 BUG_ON(!page);
 942                 __set_page_dirty_nobuffers(page);
 943                 page_cache_release(page);
 944                 index++;
 945         }
 946         set_extent_dirty(tree, start, end, GFP_NOFS);
 947         return 0;
 948 }
 949 EXPORT_SYMBOL(set_range_dirty);
 950
 951 /*
 952  * helper function to set both pages and extents in the tree writeback
 953  */
 954 int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
 955 {
 956         unsigned long index = start >> PAGE_CACHE_SHIFT;
 957         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
 958         struct page *page;
 959
 960         while (index <= end_index) {
 961                 page = find_get_page(tree->mapping, index);
 962                 BUG_ON(!page);
 963                 set_page_writeback(page);
 964                 page_cache_release(page);
 965                 index++;
 966         }
 967         set_extent_writeback(tree, start, end, GFP_NOFS);
 968         return 0;
 969 }
 970 EXPORT_SYMBOL(set_range_writeback);
 971
 972 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
 973                           u64 *start_ret, u64 *end_ret, int bits)
 974 {
 975         struct rb_node *node;
 976         struct extent_state *state;
 977         int ret = 1;
 978
 979         spin_lock_irq(&tree->lock);
 980         /*
 981          * this search will find all the extents that end after
 982          * our range starts.
 983          */
 984         node = tree_search(tree, start);
 985         if (!node) {
 986                 goto out;
 987         }
 988
 989         while(1) {
 990                 state = rb_entry(node, struct extent_state, rb_node);
 991                 if (state->end >= start && (state->state & bits)) {
 992                         *start_ret = state->start;
 993                         *end_ret = state->end;
 994                         ret = 0;
 995                         break;
 996                 }
 997                 node = rb_next(node);
 998                 if (!node)
 999                         break;
1000         }
1001 out:
1002         spin_unlock_irq(&tree->lock);
1003         return ret;
1004 }
1005 EXPORT_SYMBOL(find_first_extent_bit);
1006
1007 struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1008                                                  u64 start, int bits)
1009 {
1010         struct rb_node *node;
1011         struct extent_state *state;
1012
1013         /*
1014          * this search will find all the extents that end after
1015          * our range starts.
1016          */
1017         node = tree_search(tree, start);
1018         if (!node) {
1019                 goto out;
1020         }
1021
1022         while(1) {
1023                 state = rb_entry(node, struct extent_state, rb_node);
1024                 if (state->end >= start && (state->state & bits)) {
1025                         return state;
1026                 }
1027                 node = rb_next(node);
1028                 if (!node)
1029                         break;
1030         }
1031 out:
1032         return NULL;
1033 }
1034 EXPORT_SYMBOL(find_first_extent_bit_state);
1035
1036 u64 find_lock_delalloc_range(struct extent_io_tree *tree,
1037                              u64 *start, u64 *end, u64 max_bytes)
1038 {
1039         struct rb_node *node;
1040         struct extent_state *state;
1041         u64 cur_start = *start;
1042         u64 found = 0;
1043         u64 total_bytes = 0;
1044
1045         spin_lock_irq(&tree->lock);
1046         /*
1047          * this search will find all the extents that end after
1048          * our range starts.
1049          */
1050 search_again:
1051         node = tree_search(tree, cur_start);
1052         if (!node) {
1053                 if (!found)
1054                         *end = (u64)-1;
1055                 goto out;
1056         }
1057
1058         while(1) {
1059                 state = rb_entry(node, struct extent_state, rb_node);
1060                 if (found && state->start != cur_start) {
1061                         goto out;
1062                 }
1063                 if (!(state->state & EXTENT_DELALLOC)) {
1064                         if (!found)
1065                                 *end = state->end;
1066                         goto out;
1067                 }
1068                 if (!found) {
1069                         struct extent_state *prev_state;
1070                         struct rb_node *prev_node = node;
1071                         while(1) {
1072                                 prev_node = rb_prev(prev_node);
1073                                 if (!prev_node)
1074                                         break;
1075                                 prev_state = rb_entry(prev_node,
1076                                                       struct extent_state,
1077                                                       rb_node);
1078                                 if (!(prev_state->state & EXTENT_DELALLOC))
1079                                         break;
1080                                 state = prev_state;
1081                                 node = prev_node;
1082                         }
1083                 }
1084                 if (state->state & EXTENT_LOCKED) {
1085                         DEFINE_WAIT(wait);
1086                         atomic_inc(&state->refs);
1087                         prepare_to_wait(&state->wq, &wait,
1088                                         TASK_UNINTERRUPTIBLE);
1089                         spin_unlock_irq(&tree->lock);
1090                         schedule();
1091                         spin_lock_irq(&tree->lock);
1092                         finish_wait(&state->wq, &wait);
1093                         free_extent_state(state);
1094                         goto search_again;
1095                 }
1096                 set_state_cb(tree, state, EXTENT_LOCKED);
1097                 state->state |= EXTENT_LOCKED;
1098                 if (!found)
1099                         *start = state->start;
1100                 found++;
1101                 *end = state->end;
1102                 cur_start = state->end + 1;
1103                 node = rb_next(node);
1104                 if (!node)
1105                         break;
1106                 total_bytes += state->end - state->start + 1;
1107                 if (total_bytes >= max_bytes)
1108                         break;
1109         }
1110 out:
1111         spin_unlock_irq(&tree->lock);
1112         return found;
1113 }
1114
1115 u64 count_range_bits(struct extent_io_tree *tree,
1116                      u64 *start, u64 search_end, u64 max_bytes,
1117                      unsigned long bits)
1118 {
1119         struct rb_node *node;
1120         struct extent_state *state;
1121         u64 cur_start = *start;
1122         u64 total_bytes = 0;
1123         int found = 0;
1124
1125         if (search_end <= cur_start) {
1126                 printk("search_end %Lu start %Lu\n", search_end, cur_start);
1127                 WARN_ON(1);
1128                 return 0;
1129         }
1130
1131         spin_lock_irq(&tree->lock);
1132         if (cur_start == 0 && bits == EXTENT_DIRTY) {
1133                 total_bytes = tree->dirty_bytes;
1134                 goto out;
1135         }
1136         /*
1137          * this search will find all the extents that end after
1138          * our range starts.
1139          */
1140         node = tree_search(tree, cur_start);
1141         if (!node) {
1142                 goto out;
1143         }
1144
1145         while(1) {
1146                 state = rb_entry(node, struct extent_state, rb_node);
1147                 if (state->start > search_end)
1148                         break;
1149                 if (state->end >= cur_start && (state->state & bits)) {
1150                         total_bytes += min(search_end, state->end) + 1 -
1151                                        max(cur_start, state->start);
1152                         if (total_bytes >= max_bytes)
1153                                 break;
1154                         if (!found) {
1155                                 *start = state->start;
1156                                 found = 1;
1157                         }
1158                 }
1159                 node = rb_next(node);
1160                 if (!node)
1161                         break;
1162         }
1163 out:
1164         spin_unlock_irq(&tree->lock);
1165         return total_bytes;
1166 }
1167 /*
1168  * helper function to lock both pages and extents in the tree.
1169  * pages must be locked first.
1170  */
1171 int lock_range(struct extent_io_tree *tree, u64 start, u64 end)
1172 {
1173         unsigned long index = start >> PAGE_CACHE_SHIFT;
1174         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1175         struct page *page;
1176         int err;
1177
1178         while (index <= end_index) {
1179                 page = grab_cache_page(tree->mapping, index);
1180                 if (!page) {
1181                         err = -ENOMEM;
1182                         goto failed;
1183                 }
1184                 if (IS_ERR(page)) {
1185                         err = PTR_ERR(page);
1186                         goto failed;
1187                 }
1188                 index++;
1189         }
1190         lock_extent(tree, start, end, GFP_NOFS);
1191         return 0;
1192
1193 failed:
1194         /*
1195          * we failed above in getting the page at 'index', so we undo here
1196          * up to but not including the page at 'index'
1197          */
1198         end_index = index;
1199         index = start >> PAGE_CACHE_SHIFT;
1200         while (index < end_index) {
1201                 page = find_get_page(tree->mapping, index);
1202                 unlock_page(page);
1203                 page_cache_release(page);
1204                 index++;
1205         }
1206         return err;
1207 }
1208 EXPORT_SYMBOL(lock_range);
1209
1210 /*
1211  * helper function to unlock both pages and extents in the tree.
1212  */
1213 int unlock_range(struct extent_io_tree *tree, u64 start, u64 end)
1214 {
1215         unsigned long index = start >> PAGE_CACHE_SHIFT;
1216         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1217         struct page *page;
1218
1219         while (index <= end_index) {
1220                 page = find_get_page(tree->mapping, index);
1221                 unlock_page(page);
1222                 page_cache_release(page);
1223                 index++;
1224         }
1225         unlock_extent(tree, start, end, GFP_NOFS);
1226         return 0;
1227 }
1228 EXPORT_SYMBOL(unlock_range);
1229
1230 int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1231 {
1232         struct rb_node *node;
1233         struct extent_state *state;
1234         int ret = 0;
1235
1236         spin_lock_irq(&tree->lock);
1237         /*
1238          * this search will find all the extents that end after
1239          * our range starts.
1240          */
1241         node = tree_search(tree, start);
1242         if (!node) {
1243                 ret = -ENOENT;
1244                 goto out;
1245         }
1246         state = rb_entry(node, struct extent_state, rb_node);
1247         if (state->start != start) {
1248                 ret = -ENOENT;
1249                 goto out;
1250         }
1251         state->private = private;
1252 out:
1253         spin_unlock_irq(&tree->lock);
1254         return ret;
1255 }
1256
1257 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1258 {
1259         struct rb_node *node;
1260         struct extent_state *state;
1261         int ret = 0;
1262
1263         spin_lock_irq(&tree->lock);
1264         /*
1265          * this search will find all the extents that end after
1266          * our range starts.
1267          */
1268         node = tree_search(tree, start);
1269         if (!node) {
1270                 ret = -ENOENT;
1271                 goto out;
1272         }
1273         state = rb_entry(node, struct extent_state, rb_node);
1274         if (state->start != start) {
1275                 ret = -ENOENT;
1276                 goto out;
1277         }
1278         *private = state->private;
1279 out:
1280         spin_unlock_irq(&tree->lock);
1281         return ret;
1282 }
1283
1284 /*
1285  * searches a range in the state tree for a given mask.
1286  * If 'filled' == 1, this returns 1 only if every extent in the tree
1287  * has the bits set.  Otherwise, 1 is returned if any bit in the
1288  * range is found set.
1289  */
1290 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1291                    int bits, int filled)
1292 {
1293         struct extent_state *state = NULL;
1294         struct rb_node *node;
1295         int bitset = 0;
1296         unsigned long flags;
1297
1298         spin_lock_irqsave(&tree->lock, flags);
1299         node = tree_search(tree, start);
1300         while (node && start <= end) {
1301                 state = rb_entry(node, struct extent_state, rb_node);
1302
1303                 if (filled && state->start > start) {
1304                         bitset = 0;
1305                         break;
1306                 }
1307
1308                 if (state->start > end)
1309                         break;
1310
1311                 if (state->state & bits) {
1312                         bitset = 1;
1313                         if (!filled)
1314                                 break;
1315                 } else if (filled) {
1316                         bitset = 0;
1317                         break;
1318                 }
1319                 start = state->end + 1;
1320                 if (start > end)
1321                         break;
1322                 node = rb_next(node);
1323                 if (!node) {
1324                         if (filled)
1325                                 bitset = 0;
1326                         break;
1327                 }
1328         }
1329         spin_unlock_irqrestore(&tree->lock, flags);
1330         return bitset;
1331 }
1332 EXPORT_SYMBOL(test_range_bit);
1333
1334 /*
1335  * helper function to set a given page up to date if all the
1336  * extents in the tree for that page are up to date
1337  */
1338 static int check_page_uptodate(struct extent_io_tree *tree,
1339                                struct page *page)
1340 {
1341         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1342         u64 end = start + PAGE_CACHE_SIZE - 1;
1343         if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
1344                 SetPageUptodate(page);
1345         return 0;
1346 }
1347
1348 /*
1349  * helper function to unlock a page if all the extents in the tree
1350  * for that page are unlocked
1351  */
1352 static int check_page_locked(struct extent_io_tree *tree,
1353                              struct page *page)
1354 {
1355         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1356         u64 end = start + PAGE_CACHE_SIZE - 1;
1357         if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
1358                 unlock_page(page);
1359         return 0;
1360 }
1361
1362 /*
1363  * helper function to end page writeback if all the extents
1364  * in the tree for that page are done with writeback
1365  */
1366 static int check_page_writeback(struct extent_io_tree *tree,
1367                              struct page *page)
1368 {
1369         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1370         u64 end = start + PAGE_CACHE_SIZE - 1;
1371         if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
1372                 end_page_writeback(page);
1373         return 0;
1374 }
1375
1376 /* lots and lots of room for performance fixes in the end_bio funcs */
1377
1378 /*
1379  * after a writepage IO is done, we need to:
1380  * clear the uptodate bits on error
1381  * clear the writeback bits in the extent tree for this IO
1382  * end_page_writeback if the page has no more pending IO
1383  *
1384  * Scheduling is not allowed, so the extent state tree is expected
1385  * to have one and only one object corresponding to this IO.
1386  */
1387 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1388 static void end_bio_extent_writepage(struct bio *bio, int err)
1389 #else
1390 static int end_bio_extent_writepage(struct bio *bio,
1391                                    unsigned int bytes_done, int err)
1392 #endif
1393 {
1394         int uptodate = err == 0;
1395         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1396         struct extent_state *state = bio->bi_private;
1397         struct extent_io_tree *tree = state->tree;
1398         struct rb_node *node;
1399         u64 start;
1400         u64 end;
1401         u64 cur;
1402         int whole_page;
1403         int ret;
1404         unsigned long flags;
1405
1406 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1407         if (bio->bi_size)
1408                 return 1;
1409 #endif
1410         do {
1411                 struct page *page = bvec->bv_page;
1412                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1413                          bvec->bv_offset;
1414                 end = start + bvec->bv_len - 1;
1415
1416                 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1417                         whole_page = 1;
1418                 else
1419                         whole_page = 0;
1420
1421                 if (--bvec >= bio->bi_io_vec)
1422                         prefetchw(&bvec->bv_page->flags);
1423                 if (tree->ops && tree->ops->writepage_end_io_hook) {
1424                         ret = tree->ops->writepage_end_io_hook(page, start,
1425                                                        end, state, uptodate);
1426                         if (ret)
1427                                 uptodate = 0;
1428                 }
1429
1430                 if (!uptodate && tree->ops &&
1431                     tree->ops->writepage_io_failed_hook) {
1432                         ret = tree->ops->writepage_io_failed_hook(bio, page,
1433                                                          start, end, state);
1434                         if (ret == 0) {
1435                                 state = NULL;
1436                                 uptodate = (err == 0);
1437                                 continue;
1438                         }
1439                 }
1440
1441                 if (!uptodate) {
1442                         clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
1443                         ClearPageUptodate(page);
1444                         SetPageError(page);
1445                 }
1446
1447                 /*
1448                  * bios can get merged in funny ways, and so we need to
1449                  * be careful with the state variable.  We know the
1450                  * state won't be merged with others because it has
1451                  * WRITEBACK set, but we can't be sure each biovec is
1452                  * sequential in the file.  So, if our cached state
1453                  * doesn't match the expected end, search the tree
1454                  * for the correct one.
1455                  */
1456
1457                 spin_lock_irqsave(&tree->lock, flags);
1458                 if (!state || state->end != end) {
1459                         state = NULL;
1460                         node = __etree_search(tree, start, NULL, NULL);
1461                         if (node) {
1462                                 state = rb_entry(node, struct extent_state,
1463                                                  rb_node);
1464                                 if (state->end != end ||
1465                                     !(state->state & EXTENT_WRITEBACK))
1466                                         state = NULL;
1467                         }
1468                         if (!state) {
1469                                 spin_unlock_irqrestore(&tree->lock, flags);
1470                                 clear_extent_writeback(tree, start,
1471                                                        end, GFP_ATOMIC);
1472                                 goto next_io;
1473                         }
1474                 }
1475                 cur = end;
1476                 while(1) {
1477                         struct extent_state *clear = state;
1478                         cur = state->start;
1479                         node = rb_prev(&state->rb_node);
1480                         if (node) {
1481                                 state = rb_entry(node,
1482                                                  struct extent_state,
1483                                                  rb_node);
1484                         } else {
1485                                 state = NULL;
1486                         }
1487
1488                         clear_state_bit(tree, clear, EXTENT_WRITEBACK,
1489                                         1, 0);
1490                         if (cur == start)
1491                                 break;
1492                         if (cur < start) {
1493                                 WARN_ON(1);
1494                                 break;
1495                         }
1496                         if (!node)
1497                                 break;
1498                 }
1499                 /* before releasing the lock, make sure the next state
1500                  * variable has the expected bits set and corresponds
1501                  * to the correct offsets in the file
1502                  */
1503                 if (state && (state->end + 1 != start ||
1504                     !(state->state & EXTENT_WRITEBACK))) {
1505                         state = NULL;
1506                 }
1507                 spin_unlock_irqrestore(&tree->lock, flags);
1508 next_io:
1509
1510                 if (whole_page)
1511                         end_page_writeback(page);
1512                 else
1513                         check_page_writeback(tree, page);
1514         } while (bvec >= bio->bi_io_vec);
1515         bio_put(bio);
1516 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1517         return 0;
1518 #endif
1519 }
1520
1521 /*
1522  * after a readpage IO is done, we need to:
1523  * clear the uptodate bits on error
1524  * set the uptodate bits if things worked
1525  * set the page up to date if all extents in the tree are uptodate
1526  * clear the lock bit in the extent tree
1527  * unlock the page if there are no other extents locked for it
1528  *
1529  * Scheduling is not allowed, so the extent state tree is expected
1530  * to have one and only one object corresponding to this IO.
1531  */
1532 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1533 static void end_bio_extent_readpage(struct bio *bio, int err)
1534 #else
1535 static int end_bio_extent_readpage(struct bio *bio,
1536                                    unsigned int bytes_done, int err)
1537 #endif
1538 {
1539         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1540         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1541         struct extent_state *state = bio->bi_private;
1542         struct extent_io_tree *tree = state->tree;
1543         struct rb_node *node;
1544         u64 start;
1545         u64 end;
1546         u64 cur;
1547         unsigned long flags;
1548         int whole_page;
1549         int ret;
1550
1551 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1552         if (bio->bi_size)
1553                 return 1;
1554 #endif
1555
1556         do {
1557                 struct page *page = bvec->bv_page;
1558                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1559                         bvec->bv_offset;
1560                 end = start + bvec->bv_len - 1;
1561
1562                 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1563                         whole_page = 1;
1564                 else
1565                         whole_page = 0;
1566
1567                 if (--bvec >= bio->bi_io_vec)
1568                         prefetchw(&bvec->bv_page->flags);
1569
1570                 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1571                         ret = tree->ops->readpage_end_io_hook(page, start, end,
1572                                                               state);
1573                         if (ret)
1574                                 uptodate = 0;
1575                 }
1576                 if (!uptodate && tree->ops &&
1577                     tree->ops->readpage_io_failed_hook) {
1578                         ret = tree->ops->readpage_io_failed_hook(bio, page,
1579                                                          start, end, state);
1580                         if (ret == 0) {
1581                                 state = NULL;
1582                                 uptodate =
1583                                         test_bit(BIO_UPTODATE, &bio->bi_flags);
1584                                 continue;
1585                         }
1586                 }
1587
1588                 spin_lock_irqsave(&tree->lock, flags);
1589                 if (!state || state->end != end) {
1590                         state = NULL;
1591                         node = __etree_search(tree, start, NULL, NULL);
1592                         if (node) {
1593                                 state = rb_entry(node, struct extent_state,
1594                                                  rb_node);
1595                                 if (state->end != end ||
1596                                     !(state->state & EXTENT_LOCKED))
1597                                         state = NULL;
1598                         }
1599                         if (!state) {
1600                                 spin_unlock_irqrestore(&tree->lock, flags);
1601                                 if (uptodate)
1602                                         set_extent_uptodate(tree, start, end,
1603                                                             GFP_ATOMIC);
1604                                 unlock_extent(tree, start, end, GFP_ATOMIC);
1605                                 goto next_io;
1606                         }
1607                 }
1608
1609                 cur = end;
1610                 while(1) {
1611                         struct extent_state *clear = state;
1612                         cur = state->start;
1613                         node = rb_prev(&state->rb_node);
1614                         if (node) {
1615                                 state = rb_entry(node,
1616                                          struct extent_state,
1617                                          rb_node);
1618                         } else {
1619                                 state = NULL;
1620                         }
1621                         if (uptodate) {
1622                                 set_state_cb(tree, clear, EXTENT_UPTODATE);
1623                                 clear->state |= EXTENT_UPTODATE;
1624                         }
1625                         clear_state_bit(tree, clear, EXTENT_LOCKED,
1626                                         1, 0);
1627                         if (cur == start)
1628                                 break;
1629                         if (cur < start) {
1630                                 WARN_ON(1);
1631                                 break;
1632                         }
1633                         if (!node)
1634                                 break;
1635                 }
1636                 /* before releasing the lock, make sure the next state
1637                  * variable has the expected bits set and corresponds
1638                  * to the correct offsets in the file
1639                  */
1640                 if (state && (state->end + 1 != start ||
1641                     !(state->state & EXTENT_LOCKED))) {
1642                         state = NULL;
1643                 }
1644                 spin_unlock_irqrestore(&tree->lock, flags);
1645 next_io:
1646                 if (whole_page) {
1647                         if (uptodate) {
1648                                 SetPageUptodate(page);
1649                         } else {
1650                                 ClearPageUptodate(page);
1651                                 SetPageError(page);
1652                         }
1653                         unlock_page(page);
1654                 } else {
1655                         if (uptodate) {
1656                                 check_page_uptodate(tree, page);
1657                         } else {
1658                                 ClearPageUptodate(page);
1659                                 SetPageError(page);
1660                         }
1661                         check_page_locked(tree, page);
1662                 }
1663         } while (bvec >= bio->bi_io_vec);
1664
1665         bio_put(bio);
1666 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1667         return 0;
1668 #endif
1669 }
1670
1671 /*
1672  * IO done from prepare_write is pretty simple, we just unlock
1673  * the structs in the extent tree when done, and set the uptodate bits
1674  * as appropriate.
1675  */
1676 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1677 static void end_bio_extent_preparewrite(struct bio *bio, int err)
1678 #else
1679 static int end_bio_extent_preparewrite(struct bio *bio,
1680                                        unsigned int bytes_done, int err)
1681 #endif
1682 {
1683         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1684         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1685         struct extent_state *state = bio->bi_private;
1686         struct extent_io_tree *tree = state->tree;
1687         u64 start;
1688         u64 end;
1689
1690 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1691         if (bio->bi_size)
1692                 return 1;
1693 #endif
1694
1695         do {
1696                 struct page *page = bvec->bv_page;
1697                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1698                         bvec->bv_offset;
1699                 end = start + bvec->bv_len - 1;
1700
1701                 if (--bvec >= bio->bi_io_vec)
1702                         prefetchw(&bvec->bv_page->flags);
1703
1704                 if (uptodate) {
1705                         set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1706                 } else {
1707                         ClearPageUptodate(page);
1708                         SetPageError(page);
1709                 }
1710
1711                 unlock_extent(tree, start, end, GFP_ATOMIC);
1712
1713         } while (bvec >= bio->bi_io_vec);
1714
1715         bio_put(bio);
1716 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1717         return 0;
1718 #endif
1719 }
1720
1721 static struct bio *
1722 extent_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1723                  gfp_t gfp_flags)
1724 {
1725         struct bio *bio;
1726
1727         bio = bio_alloc(gfp_flags, nr_vecs);
1728
1729         if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1730                 while (!bio && (nr_vecs /= 2))
1731                         bio = bio_alloc(gfp_flags, nr_vecs);
1732         }
1733
1734         if (bio) {
1735                 bio->bi_size = 0;
1736                 bio->bi_bdev = bdev;
1737                 bio->bi_sector = first_sector;
1738         }
1739         return bio;
1740 }
1741
1742 static int submit_one_bio(int rw, struct bio *bio, int mirror_num)
1743 {
1744         int ret = 0;
1745         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1746         struct page *page = bvec->bv_page;
1747         struct extent_io_tree *tree = bio->bi_private;
1748         struct rb_node *node;
1749         struct extent_state *state;
1750         u64 start;
1751         u64 end;
1752
1753         start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1754         end = start + bvec->bv_len - 1;
1755
1756         spin_lock_irq(&tree->lock);
1757         node = __etree_search(tree, start, NULL, NULL);
1758         BUG_ON(!node);
1759         state = rb_entry(node, struct extent_state, rb_node);
1760         while(state->end < end) {
1761                 node = rb_next(node);
1762                 state = rb_entry(node, struct extent_state, rb_node);
1763         }
1764         BUG_ON(state->end != end);
1765         spin_unlock_irq(&tree->lock);
1766
1767         bio->bi_private = state;
1768
1769         bio_get(bio);
1770
1771         if (tree->ops && tree->ops->submit_bio_hook)
1772                 tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1773                                            mirror_num);
1774         else
1775                 submit_bio(rw, bio);
1776         if (bio_flagged(bio, BIO_EOPNOTSUPP))
1777                 ret = -EOPNOTSUPP;
1778         bio_put(bio);
1779         return ret;
1780 }
1781
1782 static int submit_extent_page(int rw, struct extent_io_tree *tree,
1783                               struct page *page, sector_t sector,
1784                               size_t size, unsigned long offset,
1785                               struct block_device *bdev,
1786                               struct bio **bio_ret,
1787                               unsigned long max_pages,
1788                               bio_end_io_t end_io_func,
1789                               int mirror_num)
1790 {
1791         int ret = 0;
1792         struct bio *bio;
1793         int nr;
1794
1795         if (bio_ret && *bio_ret) {
1796                 bio = *bio_ret;
1797                 if (bio->bi_sector + (bio->bi_size >> 9) != sector ||
1798                     (tree->ops && tree->ops->merge_bio_hook &&
1799                      tree->ops->merge_bio_hook(page, offset, size, bio)) ||
1800                     bio_add_page(bio, page, size, offset) < size) {
1801                         ret = submit_one_bio(rw, bio, mirror_num);
1802                         bio = NULL;
1803                 } else {
1804                         return 0;
1805                 }
1806         }
1807         nr = bio_get_nr_vecs(bdev);
1808         bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1809         if (!bio) {
1810                 printk("failed to allocate bio nr %d\n", nr);
1811         }
1812
1813
1814         bio_add_page(bio, page, size, offset);
1815         bio->bi_end_io = end_io_func;
1816         bio->bi_private = tree;
1817
1818         if (bio_ret) {
1819                 *bio_ret = bio;
1820         } else {
1821                 ret = submit_one_bio(rw, bio, mirror_num);
1822         }
1823
1824         return ret;
1825 }
1826
1827 void set_page_extent_mapped(struct page *page)
1828 {
1829         if (!PagePrivate(page)) {
1830                 SetPagePrivate(page);
1831                 page_cache_get(page);
1832                 set_page_private(page, EXTENT_PAGE_PRIVATE);
1833         }
1834 }
1835
1836 void set_page_extent_head(struct page *page, unsigned long len)
1837 {
1838         set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1839 }
1840
1841 /*
1842  * basic readpage implementation.  Locked extent state structs are inserted
1843  * into the tree that are removed when the IO is done (by the end_io
1844  * handlers)
1845  */
1846 static int __extent_read_full_page(struct extent_io_tree *tree,
1847                                    struct page *page,
1848                                    get_extent_t *get_extent,
1849                                    struct bio **bio, int mirror_num)
1850 {
1851         struct inode *inode = page->mapping->host;
1852         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1853         u64 page_end = start + PAGE_CACHE_SIZE - 1;
1854         u64 end;
1855         u64 cur = start;
1856         u64 extent_offset;
1857         u64 last_byte = i_size_read(inode);
1858         u64 block_start;
1859         u64 cur_end;
1860         sector_t sector;
1861         struct extent_map *em;
1862         struct block_device *bdev;
1863         int ret;
1864         int nr = 0;
1865         size_t page_offset = 0;
1866         size_t iosize;
1867         size_t blocksize = inode->i_sb->s_blocksize;
1868
1869         set_page_extent_mapped(page);
1870
1871         end = page_end;
1872         lock_extent(tree, start, end, GFP_NOFS);
1873
1874         while (cur <= end) {
1875                 if (cur >= last_byte) {
1876                         char *userpage;
1877                         iosize = PAGE_CACHE_SIZE - page_offset;
1878                         userpage = kmap_atomic(page, KM_USER0);
1879                         memset(userpage + page_offset, 0, iosize);
1880                         flush_dcache_page(page);
1881                         kunmap_atomic(userpage, KM_USER0);
1882                         set_extent_uptodate(tree, cur, cur + iosize - 1,
1883                                             GFP_NOFS);
1884                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1885                         break;
1886                 }
1887                 em = get_extent(inode, page, page_offset, cur,
1888                                 end - cur + 1, 0);
1889                 if (IS_ERR(em) || !em) {
1890                         SetPageError(page);
1891                         unlock_extent(tree, cur, end, GFP_NOFS);
1892                         break;
1893                 }
1894                 extent_offset = cur - em->start;
1895                 if (extent_map_end(em) <= cur) {
1896 printk("bad mapping em [%Lu %Lu] cur %Lu\n", em->start, extent_map_end(em), cur);
1897                 }
1898                 BUG_ON(extent_map_end(em) <= cur);
1899                 if (end < cur) {
1900 printk("2bad mapping end %Lu cur %Lu\n", end, cur);
1901                 }
1902                 BUG_ON(end < cur);
1903
1904                 iosize = min(extent_map_end(em) - cur, end - cur + 1);
1905                 cur_end = min(extent_map_end(em) - 1, end);
1906                 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1907                 sector = (em->block_start + extent_offset) >> 9;
1908                 bdev = em->bdev;
1909                 block_start = em->block_start;
1910                 free_extent_map(em);
1911                 em = NULL;
1912
1913                 /* we've found a hole, just zero and go on */
1914                 if (block_start == EXTENT_MAP_HOLE) {
1915                         char *userpage;
1916                         userpage = kmap_atomic(page, KM_USER0);
1917                         memset(userpage + page_offset, 0, iosize);
1918                         flush_dcache_page(page);
1919                         kunmap_atomic(userpage, KM_USER0);
1920
1921                         set_extent_uptodate(tree, cur, cur + iosize - 1,
1922                                             GFP_NOFS);
1923                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1924                         cur = cur + iosize;
1925                         page_offset += iosize;
1926                         continue;
1927                 }
1928                 /* the get_extent function already copied into the page */
1929                 if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
1930                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1931                         cur = cur + iosize;
1932                         page_offset += iosize;
1933                         continue;
1934                 }
1935                 /* we have an inline extent but it didn't get marked up
1936                  * to date.  Error out
1937                  */
1938                 if (block_start == EXTENT_MAP_INLINE) {
1939                         SetPageError(page);
1940                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1941                         cur = cur + iosize;
1942                         page_offset += iosize;
1943                         continue;
1944                 }
1945
1946                 ret = 0;
1947                 if (tree->ops && tree->ops->readpage_io_hook) {
1948                         ret = tree->ops->readpage_io_hook(page, cur,
1949                                                           cur + iosize - 1);
1950                 }
1951                 if (!ret) {
1952                         unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
1953                         pnr -= page->index;
1954                         ret = submit_extent_page(READ, tree, page,
1955                                          sector, iosize, page_offset,
1956                                          bdev, bio, pnr,
1957                                          end_bio_extent_readpage, mirror_num);
1958                         nr++;
1959                 }
1960                 if (ret)
1961                         SetPageError(page);
1962                 cur = cur + iosize;
1963                 page_offset += iosize;
1964         }
1965         if (!nr) {
1966                 if (!PageError(page))
1967                         SetPageUptodate(page);
1968                 unlock_page(page);
1969         }
1970         return 0;
1971 }
1972
1973 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
1974                             get_extent_t *get_extent)
1975 {
1976         struct bio *bio = NULL;
1977         int ret;
1978
1979         ret = __extent_read_full_page(tree, page, get_extent, &bio, 0);
1980         if (bio)
1981                 submit_one_bio(READ, bio, 0);
1982         return ret;
1983 }
1984 EXPORT_SYMBOL(extent_read_full_page);
1985
1986 /*
1987  * the writepage semantics are similar to regular writepage.  extent
1988  * records are inserted to lock ranges in the tree, and as dirty areas
1989  * are found, they are marked writeback.  Then the lock bits are removed
1990  * and the end_io handler clears the writeback ranges
1991  */
1992 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
1993                               void *data)
1994 {
1995         struct inode *inode = page->mapping->host;
1996         struct extent_page_data *epd = data;
1997         struct extent_io_tree *tree = epd->tree;
1998         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1999         u64 delalloc_start;
2000         u64 page_end = start + PAGE_CACHE_SIZE - 1;
2001         u64 end;
2002         u64 cur = start;
2003         u64 extent_offset;
2004         u64 last_byte = i_size_read(inode);
2005         u64 block_start;
2006         u64 iosize;
2007         u64 unlock_start;
2008         sector_t sector;
2009         struct extent_map *em;
2010         struct block_device *bdev;
2011         int ret;
2012         int nr = 0;
2013         size_t pg_offset = 0;
2014         size_t blocksize;
2015         loff_t i_size = i_size_read(inode);
2016         unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2017         u64 nr_delalloc;
2018         u64 delalloc_end;
2019
2020         WARN_ON(!PageLocked(page));
2021         pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2022         if (page->index > end_index ||
2023            (page->index == end_index && !pg_offset)) {
2024                 page->mapping->a_ops->invalidatepage(page, 0);
2025                 unlock_page(page);
2026                 return 0;
2027         }
2028
2029         if (page->index == end_index) {
2030                 char *userpage;
2031
2032                 userpage = kmap_atomic(page, KM_USER0);
2033                 memset(userpage + pg_offset, 0,
2034                        PAGE_CACHE_SIZE - pg_offset);
2035                 kunmap_atomic(userpage, KM_USER0);
2036                 flush_dcache_page(page);
2037         }
2038         pg_offset = 0;
2039
2040         set_page_extent_mapped(page);
2041
2042         delalloc_start = start;
2043         delalloc_end = 0;
2044         while(delalloc_end < page_end) {
2045                 nr_delalloc = find_lock_delalloc_range(tree, &delalloc_start,
2046                                                        &delalloc_end,
2047                                                        128 * 1024 * 1024);
2048                 if (nr_delalloc == 0) {
2049                         delalloc_start = delalloc_end + 1;
2050                         continue;
2051                 }
2052                 tree->ops->fill_delalloc(inode, delalloc_start,
2053                                          delalloc_end);
2054                 clear_extent_bit(tree, delalloc_start,
2055                                  delalloc_end,
2056                                  EXTENT_LOCKED | EXTENT_DELALLOC,
2057                                  1, 0, GFP_NOFS);
2058                 delalloc_start = delalloc_end + 1;
2059         }
2060         lock_extent(tree, start, page_end, GFP_NOFS);
2061         unlock_start = start;
2062
2063         if (tree->ops && tree->ops->writepage_start_hook) {
2064                 ret = tree->ops->writepage_start_hook(page, start, page_end);
2065                 if (ret == -EAGAIN) {
2066                         unlock_extent(tree, start, page_end, GFP_NOFS);
2067                         redirty_page_for_writepage(wbc, page);
2068                         unlock_page(page);
2069                         return 0;
2070                 }
2071         }
2072
2073         end = page_end;
2074         if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
2075                 printk("found delalloc bits after lock_extent\n");
2076         }
2077
2078         if (last_byte <= start) {
2079                 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
2080                 unlock_extent(tree, start, page_end, GFP_NOFS);
2081                 if (tree->ops && tree->ops->writepage_end_io_hook)
2082                         tree->ops->writepage_end_io_hook(page, start,
2083                                                          page_end, NULL, 1);
2084                 unlock_start = page_end + 1;
2085                 goto done;
2086         }
2087
2088         set_extent_uptodate(tree, start, page_end, GFP_NOFS);
2089         blocksize = inode->i_sb->s_blocksize;
2090
2091         while (cur <= end) {
2092                 if (cur >= last_byte) {
2093                         clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
2094                         unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2095                         if (tree->ops && tree->ops->writepage_end_io_hook)
2096                                 tree->ops->writepage_end_io_hook(page, cur,
2097                                                          page_end, NULL, 1);
2098                         unlock_start = page_end + 1;
2099                         break;
2100                 }
2101                 em = epd->get_extent(inode, page, pg_offset, cur,
2102                                      end - cur + 1, 1);
2103                 if (IS_ERR(em) || !em) {
2104                         SetPageError(page);
2105                         break;
2106                 }
2107
2108                 extent_offset = cur - em->start;
2109                 BUG_ON(extent_map_end(em) <= cur);
2110                 BUG_ON(end < cur);
2111                 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2112                 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2113                 sector = (em->block_start + extent_offset) >> 9;
2114                 bdev = em->bdev;
2115                 block_start = em->block_start;
2116                 free_extent_map(em);
2117                 em = NULL;
2118
2119                 if (block_start == EXTENT_MAP_HOLE ||
2120                     block_start == EXTENT_MAP_INLINE) {
2121                         clear_extent_dirty(tree, cur,
2122                                            cur + iosize - 1, GFP_NOFS);
2123
2124                         unlock_extent(tree, unlock_start, cur + iosize -1,
2125                                       GFP_NOFS);
2126
2127                         if (tree->ops && tree->ops->writepage_end_io_hook)
2128                                 tree->ops->writepage_end_io_hook(page, cur,
2129                                                          cur + iosize - 1,
2130                                                          NULL, 1);
2131                         cur = cur + iosize;
2132                         pg_offset += iosize;
2133                         unlock_start = cur;
2134                         continue;
2135                 }
2136
2137                 /* leave this out until we have a page_mkwrite call */
2138                 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2139                                    EXTENT_DIRTY, 0)) {
2140                         cur = cur + iosize;
2141                         pg_offset += iosize;
2142                         continue;
2143                 }
2144                 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
2145                 if (tree->ops && tree->ops->writepage_io_hook) {
2146                         ret = tree->ops->writepage_io_hook(page, cur,
2147                                                 cur + iosize - 1);
2148                 } else {
2149                         ret = 0;
2150                 }
2151                 if (ret) {
2152                         SetPageError(page);
2153                 } else {
2154                         unsigned long max_nr = end_index + 1;
2155
2156                         set_range_writeback(tree, cur, cur + iosize - 1);
2157                         if (!PageWriteback(page)) {
2158                                 printk("warning page %lu not writeback, "
2159                                        "cur %llu end %llu\n", page->index,
2160                                        (unsigned long long)cur,
2161                                        (unsigned long long)end);
2162                         }
2163
2164                         ret = submit_extent_page(WRITE, tree, page, sector,
2165                                                  iosize, pg_offset, bdev,
2166                                                  &epd->bio, max_nr,
2167                                                  end_bio_extent_writepage, 0);
2168                         if (ret)
2169                                 SetPageError(page);
2170                 }
2171                 cur = cur + iosize;
2172                 pg_offset += iosize;
2173                 nr++;
2174         }
2175 done:
2176         if (nr == 0) {
2177                 /* make sure the mapping tag for page dirty gets cleared */
2178                 set_page_writeback(page);
2179                 end_page_writeback(page);
2180         }
2181         if (unlock_start <= page_end)
2182                 unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2183         unlock_page(page);
2184         return 0;
2185 }
2186
2187 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
2188 /* Taken directly from 2.6.23 for 2.6.18 back port */
2189 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
2190                                 void *data);
2191
2192 /**
2193  * write_cache_pages - walk the list of dirty pages of the given address space
2194  * and write all of them.
2195  * @mapping: address space structure to write
2196  * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2197  * @writepage: function called for each page
2198  * @data: data passed to writepage function
2199  *
2200  * If a page is already under I/O, write_cache_pages() skips it, even
2201  * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
2202  * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
2203  * and msync() need to guarantee that all the data which was dirty at the time
2204  * the call was made get new I/O started against them.  If wbc->sync_mode is
2205  * WB_SYNC_ALL then we were called for data integrity and we must wait for
2206  * existing IO to complete.
2207  */
2208 static int write_cache_pages(struct address_space *mapping,
2209                       struct writeback_control *wbc, writepage_t writepage,
2210                       void *data)
2211 {
2212         struct backing_dev_info *bdi = mapping->backing_dev_info;
2213         int ret = 0;
2214         int done = 0;
2215         struct pagevec pvec;
2216         int nr_pages;
2217         pgoff_t index;
2218         pgoff_t end;            /* Inclusive */
2219         int scanned = 0;
2220         int range_whole = 0;
2221
2222         if (wbc->nonblocking && bdi_write_congested(bdi)) {
2223                 wbc->encountered_congestion = 1;
2224                 return 0;
2225         }
2226
2227         pagevec_init(&pvec, 0);
2228         if (wbc->range_cyclic) {
2229                 index = mapping->writeback_index; /* Start from prev offset */
2230                 end = -1;
2231         } else {
2232                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2233                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2234                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2235                         range_whole = 1;
2236                 scanned = 1;
2237         }
2238 retry:
2239         while (!done && (index <= end) &&
2240                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
2241                                               PAGECACHE_TAG_DIRTY,
2242                                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2243                 unsigned i;
2244
2245                 scanned = 1;
2246                 for (i = 0; i < nr_pages; i++) {
2247                         struct page *page = pvec.pages[i];
2248
2249                         /*
2250                          * At this point we hold neither mapping->tree_lock nor
2251                          * lock on the page itself: the page may be truncated or
2252                          * invalidated (changing page->mapping to NULL), or even
2253                          * swizzled back from swapper_space to tmpfs file
2254                          * mapping
2255                          */
2256                         lock_page(page);
2257
2258                         if (unlikely(page->mapping != mapping)) {
2259                                 unlock_page(page);
2260                                 continue;
2261                         }
2262
2263                         if (!wbc->range_cyclic && page->index > end) {
2264                                 done = 1;
2265                                 unlock_page(page);
2266                                 continue;
2267                         }
2268
2269                         if (wbc->sync_mode != WB_SYNC_NONE)
2270                                 wait_on_page_writeback(page);
2271
2272                         if (PageWriteback(page) ||
2273                             !clear_page_dirty_for_io(page)) {
2274                                 unlock_page(page);
2275                                 continue;
2276                         }
2277
2278                         ret = (*writepage)(page, wbc, data);
2279
2280                         if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2281                                 unlock_page(page);
2282                                 ret = 0;
2283                         }
2284                         if (ret || (--(wbc->nr_to_write) <= 0))
2285                                 done = 1;
2286                         if (wbc->nonblocking && bdi_write_congested(bdi)) {
2287                                 wbc->encountered_congestion = 1;
2288                                 done = 1;
2289                         }
2290                 }
2291                 pagevec_release(&pvec);
2292                 cond_resched();
2293         }
2294         if (!scanned && !done) {
2295                 /*
2296                  * We hit the last page and there is more work to be done: wrap
2297                  * back to the start of the file
2298                  */
2299                 scanned = 1;
2300                 index = 0;
2301                 goto retry;
2302         }
2303         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2304                 mapping->writeback_index = index;
2305         return ret;
2306 }
2307 #endif
2308
2309 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2310                           get_extent_t *get_extent,
2311                           struct writeback_control *wbc)
2312 {
2313         int ret;
2314         struct address_space *mapping = page->mapping;
2315         struct extent_page_data epd = {
2316                 .bio = NULL,
2317                 .tree = tree,
2318                 .get_extent = get_extent,
2319         };
2320         struct writeback_control wbc_writepages = {
2321                 .bdi            = wbc->bdi,
2322                 .sync_mode      = WB_SYNC_NONE,
2323                 .older_than_this = NULL,
2324                 .nr_to_write    = 64,
2325                 .range_start    = page_offset(page) + PAGE_CACHE_SIZE,
2326                 .range_end      = (loff_t)-1,
2327         };
2328
2329
2330         ret = __extent_writepage(page, wbc, &epd);
2331
2332         write_cache_pages(mapping, &wbc_writepages, __extent_writepage, &epd);
2333         if (epd.bio) {
2334                 submit_one_bio(WRITE, epd.bio, 0);
2335         }
2336         return ret;
2337 }
2338 EXPORT_SYMBOL(extent_write_full_page);
2339
2340
2341 int extent_writepages(struct extent_io_tree *tree,
2342                       struct address_space *mapping,
2343                       get_extent_t *get_extent,
2344                       struct writeback_control *wbc)
2345 {
2346         int ret = 0;
2347         struct extent_page_data epd = {
2348                 .bio = NULL,
2349                 .tree = tree,
2350                 .get_extent = get_extent,
2351         };
2352
2353         ret = write_cache_pages(mapping, wbc, __extent_writepage, &epd);
2354         if (epd.bio) {
2355                 submit_one_bio(WRITE, epd.bio, 0);
2356         }
2357         return ret;
2358 }
2359 EXPORT_SYMBOL(extent_writepages);
2360
2361 int extent_readpages(struct extent_io_tree *tree,
2362                      struct address_space *mapping,
2363                      struct list_head *pages, unsigned nr_pages,
2364                      get_extent_t get_extent)
2365 {
2366         struct bio *bio = NULL;
2367         unsigned page_idx;
2368         struct pagevec pvec;
2369
2370         pagevec_init(&pvec, 0);
2371         for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2372                 struct page *page = list_entry(pages->prev, struct page, lru);
2373
2374                 prefetchw(&page->flags);
2375                 list_del(&page->lru);
2376                 /*
2377                  * what we want to do here is call add_to_page_cache_lru,
2378                  * but that isn't exported, so we reproduce it here
2379                  */
2380                 if (!add_to_page_cache(page, mapping,
2381                                         page->index, GFP_KERNEL)) {
2382
2383                         /* open coding of lru_cache_add, also not exported */
2384                         page_cache_get(page);
2385                         if (!pagevec_add(&pvec, page))
2386                                 __pagevec_lru_add(&pvec);
2387                         __extent_read_full_page(tree, page, get_extent,
2388                                                 &bio, 0);
2389                 }
2390                 page_cache_release(page);
2391         }
2392         if (pagevec_count(&pvec))
2393                 __pagevec_lru_add(&pvec);
2394         BUG_ON(!list_empty(pages));
2395         if (bio)
2396                 submit_one_bio(READ, bio, 0);
2397         return 0;
2398 }
2399 EXPORT_SYMBOL(extent_readpages);
2400
2401 /*
2402  * basic invalidatepage code, this waits on any locked or writeback
2403  * ranges corresponding to the page, and then deletes any extent state
2404  * records from the tree
2405  */
2406 int extent_invalidatepage(struct extent_io_tree *tree,
2407                           struct page *page, unsigned long offset)
2408 {
2409         u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2410         u64 end = start + PAGE_CACHE_SIZE - 1;
2411         size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2412
2413         start += (offset + blocksize -1) & ~(blocksize - 1);
2414         if (start > end)
2415                 return 0;
2416
2417         lock_extent(tree, start, end, GFP_NOFS);
2418         wait_on_extent_writeback(tree, start, end);
2419         clear_extent_bit(tree, start, end,
2420                          EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
2421                          1, 1, GFP_NOFS);
2422         return 0;
2423 }
2424 EXPORT_SYMBOL(extent_invalidatepage);
2425
2426 /*
2427  * simple commit_write call, set_range_dirty is used to mark both
2428  * the pages and the extent records as dirty
2429  */
2430 int extent_commit_write(struct extent_io_tree *tree,
2431                         struct inode *inode, struct page *page,
2432                         unsigned from, unsigned to)
2433 {
2434         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
2435
2436         set_page_extent_mapped(page);
2437         set_page_dirty(page);
2438
2439         if (pos > inode->i_size) {
2440                 i_size_write(inode, pos);
2441                 mark_inode_dirty(inode);
2442         }
2443         return 0;
2444 }
2445 EXPORT_SYMBOL(extent_commit_write);
2446
2447 int extent_prepare_write(struct extent_io_tree *tree,
2448                          struct inode *inode, struct page *page,
2449                          unsigned from, unsigned to, get_extent_t *get_extent)
2450 {
2451         u64 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2452         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
2453         u64 block_start;
2454         u64 orig_block_start;
2455         u64 block_end;
2456         u64 cur_end;
2457         struct extent_map *em;
2458         unsigned blocksize = 1 << inode->i_blkbits;
2459         size_t page_offset = 0;
2460         size_t block_off_start;
2461         size_t block_off_end;
2462         int err = 0;
2463         int iocount = 0;
2464         int ret = 0;
2465         int isnew;
2466
2467         set_page_extent_mapped(page);
2468
2469         block_start = (page_start + from) & ~((u64)blocksize - 1);
2470         block_end = (page_start + to - 1) | (blocksize - 1);
2471         orig_block_start = block_start;
2472
2473         lock_extent(tree, page_start, page_end, GFP_NOFS);
2474         while(block_start <= block_end) {
2475                 em = get_extent(inode, page, page_offset, block_start,
2476                                 block_end - block_start + 1, 1);
2477                 if (IS_ERR(em) || !em) {
2478                         goto err;
2479                 }
2480                 cur_end = min(block_end, extent_map_end(em) - 1);
2481                 block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
2482                 block_off_end = block_off_start + blocksize;
2483                 isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
2484
2485                 if (!PageUptodate(page) && isnew &&
2486                     (block_off_end > to || block_off_start < from)) {
2487                         void *kaddr;
2488
2489                         kaddr = kmap_atomic(page, KM_USER0);
2490                         if (block_off_end > to)
2491                                 memset(kaddr + to, 0, block_off_end - to);
2492                         if (block_off_start < from)
2493                                 memset(kaddr + block_off_start, 0,
2494                                        from - block_off_start);
2495                         flush_dcache_page(page);
2496                         kunmap_atomic(kaddr, KM_USER0);
2497                 }
2498                 if ((em->block_start != EXTENT_MAP_HOLE &&
2499                      em->block_start != EXTENT_MAP_INLINE) &&
2500                     !isnew && !PageUptodate(page) &&
2501                     (block_off_end > to || block_off_start < from) &&
2502                     !test_range_bit(tree, block_start, cur_end,
2503                                     EXTENT_UPTODATE, 1)) {
2504                         u64 sector;
2505                         u64 extent_offset = block_start - em->start;
2506                         size_t iosize;
2507                         sector = (em->block_start + extent_offset) >> 9;
2508                         iosize = (cur_end - block_start + blocksize) &
2509                                 ~((u64)blocksize - 1);
2510                         /*
2511                          * we've already got the extent locked, but we
2512                          * need to split the state such that our end_bio
2513                          * handler can clear the lock.
2514                          */
2515                         set_extent_bit(tree, block_start,
2516                                        block_start + iosize - 1,
2517                                        EXTENT_LOCKED, 0, NULL, GFP_NOFS);
2518                         ret = submit_extent_page(READ, tree, page,
2519                                          sector, iosize, page_offset, em->bdev,
2520                                          NULL, 1,
2521                                          end_bio_extent_preparewrite, 0);
2522                         iocount++;
2523                         block_start = block_start + iosize;
2524                 } else {
2525                         set_extent_uptodate(tree, block_start, cur_end,
2526                                             GFP_NOFS);
2527                         unlock_extent(tree, block_start, cur_end, GFP_NOFS);
2528                         block_start = cur_end + 1;
2529                 }
2530                 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
2531                 free_extent_map(em);
2532         }
2533         if (iocount) {
2534                 wait_extent_bit(tree, orig_block_start,
2535                                 block_end, EXTENT_LOCKED);
2536         }
2537         check_page_uptodate(tree, page);
2538 err:
2539         /* FIXME, zero out newly allocated blocks on error */
2540         return err;
2541 }
2542 EXPORT_SYMBOL(extent_prepare_write);
2543
2544 /*
2545  * a helper for releasepage, this tests for areas of the page that
2546  * are locked or under IO and drops the related state bits if it is safe
2547  * to drop the page.
2548  */
2549 int try_release_extent_state(struct extent_map_tree *map,
2550                              struct extent_io_tree *tree, struct page *page,
2551                              gfp_t mask)
2552 {
2553         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2554         u64 end = start + PAGE_CACHE_SIZE - 1;
2555         int ret = 1;
2556
2557         if (test_range_bit(tree, start, end,
2558                            EXTENT_IOBITS | EXTENT_ORDERED, 0))
2559                 ret = 0;
2560         else {
2561                 if ((mask & GFP_NOFS) == GFP_NOFS)
2562                         mask = GFP_NOFS;
2563                 clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
2564                                  1, 1, mask);
2565         }
2566         return ret;
2567 }
2568 EXPORT_SYMBOL(try_release_extent_state);
2569
2570 /*
2571  * a helper for releasepage.  As long as there are no locked extents
2572  * in the range corresponding to the page, both state records and extent
2573  * map records are removed
2574  */
2575 int try_release_extent_mapping(struct extent_map_tree *map,
2576                                struct extent_io_tree *tree, struct page *page,
2577                                gfp_t mask)
2578 {
2579         struct extent_map *em;
2580         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2581         u64 end = start + PAGE_CACHE_SIZE - 1;
2582
2583         if ((mask & __GFP_WAIT) &&
2584             page->mapping->host->i_size > 16 * 1024 * 1024) {
2585                 u64 len;
2586                 while (start <= end) {
2587                         len = end - start + 1;
2588                         spin_lock(&map->lock);
2589                         em = lookup_extent_mapping(map, start, len);
2590                         if (!em || IS_ERR(em)) {
2591                                 spin_unlock(&map->lock);
2592                                 break;
2593                         }
2594                         if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2595                             em->start != start) {
2596                                 spin_unlock(&map->lock);
2597                                 free_extent_map(em);
2598                                 break;
2599                         }
2600                         if (!test_range_bit(tree, em->start,
2601                                             extent_map_end(em) - 1,
2602                                             EXTENT_LOCKED, 0)) {
2603                                 remove_extent_mapping(map, em);
2604                                 /* once for the rb tree */
2605                                 free_extent_map(em);
2606                         }
2607                         start = extent_map_end(em);
2608                         spin_unlock(&map->lock);
2609
2610                         /* once for us */
2611                         free_extent_map(em);
2612                 }
2613         }
2614         return try_release_extent_state(map, tree, page, mask);
2615 }
2616 EXPORT_SYMBOL(try_release_extent_mapping);
2617
2618 sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
2619                 get_extent_t *get_extent)
2620 {
2621         struct inode *inode = mapping->host;
2622         u64 start = iblock << inode->i_blkbits;
2623         sector_t sector = 0;
2624         struct extent_map *em;
2625
2626         em = get_extent(inode, NULL, 0, start, (1 << inode->i_blkbits), 0);
2627         if (!em || IS_ERR(em))
2628                 return 0;
2629
2630         if (em->block_start == EXTENT_MAP_INLINE ||
2631             em->block_start == EXTENT_MAP_HOLE)
2632                 goto out;
2633
2634         sector = (em->block_start + start - em->start) >> inode->i_blkbits;
2635 out:
2636         free_extent_map(em);
2637         return sector;
2638 }
2639
2640 static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2641                                               unsigned long i)
2642 {
2643         struct page *p;
2644         struct address_space *mapping;
2645
2646         if (i == 0)
2647                 return eb->first_page;
2648         i += eb->start >> PAGE_CACHE_SHIFT;
2649         mapping = eb->first_page->mapping;
2650         if (!mapping)
2651                 return NULL;
2652
2653         /*
2654          * extent_buffer_page is only called after pinning the page
2655          * by increasing the reference count.  So we know the page must
2656          * be in the radix tree.
2657          */
2658 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
2659         rcu_read_lock();
2660 #else
2661         read_lock_irq(&mapping->tree_lock);
2662 #endif
2663         p = radix_tree_lookup(&mapping->page_tree, i);
2664
2665 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
2666         rcu_read_unlock();
2667 #else
2668         read_unlock_irq(&mapping->tree_lock);
2669 #endif
2670         return p;
2671 }
2672
2673 static inline unsigned long num_extent_pages(u64 start, u64 len)
2674 {
2675         return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2676                 (start >> PAGE_CACHE_SHIFT);
2677 }
2678
2679 static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2680                                                    u64 start,
2681                                                    unsigned long len,
2682                                                    gfp_t mask)
2683 {
2684         struct extent_buffer *eb = NULL;
2685         unsigned long flags;
2686
2687         eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2688         eb->start = start;
2689         eb->len = len;
2690         mutex_init(&eb->mutex);
2691         spin_lock_irqsave(&leak_lock, flags);
2692         list_add(&eb->leak_list, &buffers);
2693         spin_unlock_irqrestore(&leak_lock, flags);
2694         atomic_set(&eb->refs, 1);
2695
2696         return eb;
2697 }
2698
2699 static void __free_extent_buffer(struct extent_buffer *eb)
2700 {
2701         unsigned long flags;
2702         spin_lock_irqsave(&leak_lock, flags);
2703         list_del(&eb->leak_list);
2704         spin_unlock_irqrestore(&leak_lock, flags);
2705         kmem_cache_free(extent_buffer_cache, eb);
2706 }
2707
2708 struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
2709                                           u64 start, unsigned long len,
2710                                           struct page *page0,
2711                                           gfp_t mask)
2712 {
2713         unsigned long num_pages = num_extent_pages(start, len);
2714         unsigned long i;
2715         unsigned long index = start >> PAGE_CACHE_SHIFT;
2716         struct extent_buffer *eb;
2717         struct extent_buffer *exists = NULL;
2718         struct page *p;
2719         struct address_space *mapping = tree->mapping;
2720         int uptodate = 1;
2721
2722         spin_lock(&tree->buffer_lock);
2723         eb = buffer_search(tree, start);
2724         if (eb) {
2725                 atomic_inc(&eb->refs);
2726                 spin_unlock(&tree->buffer_lock);
2727                 return eb;
2728         }
2729         spin_unlock(&tree->buffer_lock);
2730
2731         eb = __alloc_extent_buffer(tree, start, len, mask);
2732         if (!eb)
2733                 return NULL;
2734
2735         if (page0) {
2736                 eb->first_page = page0;
2737                 i = 1;
2738                 index++;
2739                 page_cache_get(page0);
2740                 mark_page_accessed(page0);
2741                 set_page_extent_mapped(page0);
2742                 set_page_extent_head(page0, len);
2743                 uptodate = PageUptodate(page0);
2744         } else {
2745                 i = 0;
2746         }
2747         for (; i < num_pages; i++, index++) {
2748                 p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
2749                 if (!p) {
2750                         WARN_ON(1);
2751                         goto free_eb;
2752                 }
2753                 set_page_extent_mapped(p);
2754                 mark_page_accessed(p);
2755                 if (i == 0) {
2756                         eb->first_page = p;
2757                         set_page_extent_head(p, len);
2758                 } else {
2759                         set_page_private(p, EXTENT_PAGE_PRIVATE);
2760                 }
2761                 if (!PageUptodate(p))
2762                         uptodate = 0;
2763                 unlock_page(p);
2764         }
2765         if (uptodate)
2766                 eb->flags |= EXTENT_UPTODATE;
2767         eb->flags |= EXTENT_BUFFER_FILLED;
2768
2769         spin_lock(&tree->buffer_lock);
2770         exists = buffer_tree_insert(tree, start, &eb->rb_node);
2771         if (exists) {
2772                 /* add one reference for the caller */
2773                 atomic_inc(&exists->refs);
2774                 spin_unlock(&tree->buffer_lock);
2775                 goto free_eb;
2776         }
2777         spin_unlock(&tree->buffer_lock);
2778
2779         /* add one reference for the tree */
2780         atomic_inc(&eb->refs);
2781         return eb;
2782
2783 free_eb:
2784         if (!atomic_dec_and_test(&eb->refs))
2785                 return exists;
2786         for (index = 1; index < i; index++)
2787                 page_cache_release(extent_buffer_page(eb, index));
2788         page_cache_release(extent_buffer_page(eb, 0));
2789         __free_extent_buffer(eb);
2790         return exists;
2791 }
2792 EXPORT_SYMBOL(alloc_extent_buffer);
2793
2794 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
2795                                          u64 start, unsigned long len,
2796                                           gfp_t mask)
2797 {
2798         struct extent_buffer *eb;
2799
2800         spin_lock(&tree->buffer_lock);
2801         eb = buffer_search(tree, start);
2802         if (eb)
2803                 atomic_inc(&eb->refs);
2804         spin_unlock(&tree->buffer_lock);
2805
2806         return eb;
2807 }
2808 EXPORT_SYMBOL(find_extent_buffer);
2809
2810 void free_extent_buffer(struct extent_buffer *eb)
2811 {
2812         if (!eb)
2813                 return;
2814
2815         if (!atomic_dec_and_test(&eb->refs))
2816                 return;
2817
2818         WARN_ON(1);
2819 }
2820 EXPORT_SYMBOL(free_extent_buffer);
2821
2822 int clear_extent_buffer_dirty(struct extent_io_tree *tree,
2823                               struct extent_buffer *eb)
2824 {
2825         int set;
2826         unsigned long i;
2827         unsigned long num_pages;
2828         struct page *page;
2829
2830         u64 start = eb->start;
2831         u64 end = start + eb->len - 1;
2832
2833         set = clear_extent_dirty(tree, start, end, GFP_NOFS);
2834         num_pages = num_extent_pages(eb->start, eb->len);
2835
2836         for (i = 0; i < num_pages; i++) {
2837                 page = extent_buffer_page(eb, i);
2838                 lock_page(page);
2839                 if (i == 0)
2840                         set_page_extent_head(page, eb->len);
2841                 else
2842                         set_page_private(page, EXTENT_PAGE_PRIVATE);
2843
2844                 /*
2845                  * if we're on the last page or the first page and the
2846                  * block isn't aligned on a page boundary, do extra checks
2847                  * to make sure we don't clean page that is partially dirty
2848                  */
2849                 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
2850                     ((i == num_pages - 1) &&
2851                      ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
2852                         start = (u64)page->index << PAGE_CACHE_SHIFT;
2853                         end  = start + PAGE_CACHE_SIZE - 1;
2854                         if (test_range_bit(tree, start, end,
2855                                            EXTENT_DIRTY, 0)) {
2856                                 unlock_page(page);
2857                                 continue;
2858                         }
2859                 }
2860                 clear_page_dirty_for_io(page);
2861 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
2862                 spin_lock_irq(&page->mapping->tree_lock);
2863 #else
2864                 read_lock_irq(&page->mapping->tree_lock);
2865 #endif
2866                 if (!PageDirty(page)) {
2867                         radix_tree_tag_clear(&page->mapping->page_tree,
2868                                                 page_index(page),
2869                                                 PAGECACHE_TAG_DIRTY);
2870                 }
2871 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
2872                 spin_unlock_irq(&page->mapping->tree_lock);
2873 #else
2874                 read_unlock_irq(&page->mapping->tree_lock);
2875 #endif
2876                 unlock_page(page);
2877         }
2878         return 0;
2879 }
2880 EXPORT_SYMBOL(clear_extent_buffer_dirty);
2881
2882 int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
2883                                     struct extent_buffer *eb)
2884 {
2885         return wait_on_extent_writeback(tree, eb->start,
2886                                         eb->start + eb->len - 1);
2887 }
2888 EXPORT_SYMBOL(wait_on_extent_buffer_writeback);
2889
2890 int set_extent_buffer_dirty(struct extent_io_tree *tree,
2891                              struct extent_buffer *eb)
2892 {
2893         unsigned long i;
2894         unsigned long num_pages;
2895
2896         num_pages = num_extent_pages(eb->start, eb->len);
2897         for (i = 0; i < num_pages; i++) {
2898                 struct page *page = extent_buffer_page(eb, i);
2899                 /* writepage may need to do something special for the
2900                  * first page, we have to make sure page->private is
2901                  * properly set.  releasepage may drop page->private
2902                  * on us if the page isn't already dirty.
2903                  */
2904                 if (i == 0) {
2905                         lock_page(page);
2906                         set_page_extent_head(page, eb->len);
2907                 } else if (PagePrivate(page) &&
2908                            page->private != EXTENT_PAGE_PRIVATE) {
2909                         lock_page(page);
2910                         set_page_extent_mapped(page);
2911                         unlock_page(page);
2912                 }
2913                 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
2914                 if (i == 0)
2915                         unlock_page(page);
2916         }
2917         return set_extent_dirty(tree, eb->start,
2918                                 eb->start + eb->len - 1, GFP_NOFS);
2919 }
2920 EXPORT_SYMBOL(set_extent_buffer_dirty);
2921
2922 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
2923                                 struct extent_buffer *eb)
2924 {
2925         unsigned long i;
2926         struct page *page;
2927         unsigned long num_pages;
2928
2929         num_pages = num_extent_pages(eb->start, eb->len);
2930         eb->flags &= ~EXTENT_UPTODATE;
2931
2932         clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
2933                               GFP_NOFS);
2934         for (i = 0; i < num_pages; i++) {
2935                 page = extent_buffer_page(eb, i);
2936                 if (page)
2937                         ClearPageUptodate(page);
2938         }
2939         return 0;
2940 }
2941
2942 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
2943                                 struct extent_buffer *eb)
2944 {
2945         unsigned long i;
2946         struct page *page;
2947         unsigned long num_pages;
2948
2949         num_pages = num_extent_pages(eb->start, eb->len);
2950
2951         set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
2952                             GFP_NOFS);
2953         for (i = 0; i < num_pages; i++) {
2954                 page = extent_buffer_page(eb, i);
2955                 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
2956                     ((i == num_pages - 1) &&
2957                      ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
2958                         check_page_uptodate(tree, page);
2959                         continue;
2960                 }
2961                 SetPageUptodate(page);
2962         }
2963         return 0;
2964 }
2965 EXPORT_SYMBOL(set_extent_buffer_uptodate);
2966
2967 int extent_range_uptodate(struct extent_io_tree *tree,
2968                           u64 start, u64 end)
2969 {
2970         struct page *page;
2971         int ret;
2972         int pg_uptodate = 1;
2973         int uptodate;
2974         unsigned long index;
2975
2976         ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
2977         if (ret)
2978                 return 1;
2979         while(start <= end) {
2980                 index = start >> PAGE_CACHE_SHIFT;
2981                 page = find_get_page(tree->mapping, index);
2982                 uptodate = PageUptodate(page);
2983                 page_cache_release(page);
2984                 if (!uptodate) {
2985                         pg_uptodate = 0;
2986                         break;
2987                 }
2988                 start += PAGE_CACHE_SIZE;
2989         }
2990         return pg_uptodate;
2991 }
2992
2993 int extent_buffer_uptodate(struct extent_io_tree *tree,
2994                            struct extent_buffer *eb)
2995 {
2996         int ret = 0;
2997         unsigned long num_pages;
2998         unsigned long i;
2999         struct page *page;
3000         int pg_uptodate = 1;
3001
3002         if (eb->flags & EXTENT_UPTODATE)
3003                 return 1;
3004
3005         ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3006                            EXTENT_UPTODATE, 1);
3007         if (ret)
3008                 return ret;
3009
3010         num_pages = num_extent_pages(eb->start, eb->len);
3011         for (i = 0; i < num_pages; i++) {
3012                 page = extent_buffer_page(eb, i);
3013                 if (!PageUptodate(page)) {
3014                         pg_uptodate = 0;
3015                         break;
3016                 }
3017         }
3018         return pg_uptodate;
3019 }
3020 EXPORT_SYMBOL(extent_buffer_uptodate);
3021
3022 int read_extent_buffer_pages(struct extent_io_tree *tree,
3023                              struct extent_buffer *eb,
3024                              u64 start, int wait,
3025                              get_extent_t *get_extent, int mirror_num)
3026 {
3027         unsigned long i;
3028         unsigned long start_i;
3029         struct page *page;
3030         int err;
3031         int ret = 0;
3032         int locked_pages = 0;
3033         int all_uptodate = 1;
3034         int inc_all_pages = 0;
3035         unsigned long num_pages;
3036         struct bio *bio = NULL;
3037
3038         if (eb->flags & EXTENT_UPTODATE)
3039                 return 0;
3040
3041         if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3042                            EXTENT_UPTODATE, 1)) {
3043                 return 0;
3044         }
3045
3046         if (start) {
3047                 WARN_ON(start < eb->start);
3048                 start_i = (start >> PAGE_CACHE_SHIFT) -
3049                         (eb->start >> PAGE_CACHE_SHIFT);
3050         } else {
3051                 start_i = 0;
3052         }
3053
3054         num_pages = num_extent_pages(eb->start, eb->len);
3055         for (i = start_i; i < num_pages; i++) {
3056                 page = extent_buffer_page(eb, i);
3057                 if (!wait) {
3058                         if (TestSetPageLocked(page))
3059                                 goto unlock_exit;
3060                 } else {
3061                         lock_page(page);
3062                 }
3063                 locked_pages++;
3064                 if (!PageUptodate(page)) {
3065                         all_uptodate = 0;
3066                 }
3067         }
3068         if (all_uptodate) {
3069                 if (start_i == 0)
3070                         eb->flags |= EXTENT_UPTODATE;
3071                 goto unlock_exit;
3072         }
3073
3074         for (i = start_i; i < num_pages; i++) {
3075                 page = extent_buffer_page(eb, i);
3076                 if (inc_all_pages)
3077                         page_cache_get(page);
3078                 if (!PageUptodate(page)) {
3079                         if (start_i == 0)
3080                                 inc_all_pages = 1;
3081                         ClearPageError(page);
3082                         err = __extent_read_full_page(tree, page,
3083                                                       get_extent, &bio,
3084                                                       mirror_num);
3085                         if (err) {
3086                                 ret = err;
3087                         }
3088                 } else {
3089                         unlock_page(page);
3090                 }
3091         }
3092
3093         if (bio)
3094                 submit_one_bio(READ, bio, mirror_num);
3095
3096         if (ret || !wait) {
3097                 return ret;
3098         }
3099         for (i = start_i; i < num_pages; i++) {
3100                 page = extent_buffer_page(eb, i);
3101                 wait_on_page_locked(page);
3102                 if (!PageUptodate(page)) {
3103                         ret = -EIO;
3104                 }
3105         }
3106         if (!ret)
3107                 eb->flags |= EXTENT_UPTODATE;
3108         return ret;
3109
3110 unlock_exit:
3111         i = start_i;
3112         while(locked_pages > 0) {
3113                 page = extent_buffer_page(eb, i);
3114                 i++;
3115                 unlock_page(page);
3116                 locked_pages--;
3117         }
3118         return ret;
3119 }
3120 EXPORT_SYMBOL(read_extent_buffer_pages);
3121
3122 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3123                         unsigned long start,
3124                         unsigned long len)
3125 {
3126         size_t cur;
3127         size_t offset;
3128         struct page *page;
3129         char *kaddr;
3130         char *dst = (char *)dstv;
3131         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3132         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3133
3134         WARN_ON(start > eb->len);
3135         WARN_ON(start + len > eb->start + eb->len);
3136
3137         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3138
3139         while(len > 0) {
3140                 page = extent_buffer_page(eb, i);
3141
3142                 cur = min(len, (PAGE_CACHE_SIZE - offset));
3143                 kaddr = kmap_atomic(page, KM_USER1);
3144                 memcpy(dst, kaddr + offset, cur);
3145                 kunmap_atomic(kaddr, KM_USER1);
3146
3147                 dst += cur;
3148                 len -= cur;
3149                 offset = 0;
3150                 i++;
3151         }
3152 }
3153 EXPORT_SYMBOL(read_extent_buffer);
3154
3155 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3156                                unsigned long min_len, char **token, char **map,
3157                                unsigned long *map_start,
3158                                unsigned long *map_len, int km)
3159 {
3160         size_t offset = start & (PAGE_CACHE_SIZE - 1);
3161         char *kaddr;
3162         struct page *p;
3163         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3164         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3165         unsigned long end_i = (start_offset + start + min_len - 1) >>
3166                 PAGE_CACHE_SHIFT;
3167
3168         if (i != end_i)
3169                 return -EINVAL;
3170
3171         if (i == 0) {
3172                 offset = start_offset;
3173                 *map_start = 0;
3174         } else {
3175                 offset = 0;
3176                 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3177         }
3178         if (start + min_len > eb->len) {
3179 printk("bad mapping eb start %Lu len %lu, wanted %lu %lu\n", eb->start, eb->len, start, min_len);
3180                 WARN_ON(1);
3181         }
3182
3183         p = extent_buffer_page(eb, i);
3184         kaddr = kmap_atomic(p, km);
3185         *token = kaddr;
3186         *map = kaddr + offset;
3187         *map_len = PAGE_CACHE_SIZE - offset;
3188         return 0;
3189 }
3190 EXPORT_SYMBOL(map_private_extent_buffer);
3191
3192 int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
3193                       unsigned long min_len,
3194                       char **token, char **map,
3195                       unsigned long *map_start,
3196                       unsigned long *map_len, int km)
3197 {
3198         int err;
3199         int save = 0;
3200         if (eb->map_token) {
3201                 unmap_extent_buffer(eb, eb->map_token, km);
3202                 eb->map_token = NULL;
3203                 save = 1;
3204         }
3205         err = map_private_extent_buffer(eb, start, min_len, token, map,
3206                                        map_start, map_len, km);
3207         if (!err && save) {
3208                 eb->map_token = *token;
3209                 eb->kaddr = *map;
3210                 eb->map_start = *map_start;
3211                 eb->map_len = *map_len;
3212         }
3213         return err;
3214 }
3215 EXPORT_SYMBOL(map_extent_buffer);
3216
3217 void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
3218 {
3219         kunmap_atomic(token, km);
3220 }
3221 EXPORT_SYMBOL(unmap_extent_buffer);
3222
3223 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3224                           unsigned long start,
3225                           unsigned long len)
3226 {
3227         size_t cur;
3228         size_t offset;
3229         struct page *page;
3230         char *kaddr;
3231         char *ptr = (char *)ptrv;
3232         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3233         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3234         int ret = 0;
3235
3236         WARN_ON(start > eb->len);
3237         WARN_ON(start + len > eb->start + eb->len);
3238
3239         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3240
3241         while(len > 0) {
3242                 page = extent_buffer_page(eb, i);
3243
3244                 cur = min(len, (PAGE_CACHE_SIZE - offset));
3245
3246                 kaddr = kmap_atomic(page, KM_USER0);
3247                 ret = memcmp(ptr, kaddr + offset, cur);
3248                 kunmap_atomic(kaddr, KM_USER0);
3249                 if (ret)
3250                         break;
3251
3252                 ptr += cur;
3253                 len -= cur;
3254                 offset = 0;
3255                 i++;
3256         }
3257         return ret;
3258 }
3259 EXPORT_SYMBOL(memcmp_extent_buffer);
3260
3261 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3262                          unsigned long start, unsigned long len)
3263 {
3264         size_t cur;
3265         size_t offset;
3266         struct page *page;
3267         char *kaddr;
3268         char *src = (char *)srcv;
3269         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3270         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3271
3272         WARN_ON(start > eb->len);
3273         WARN_ON(start + len > eb->start + eb->len);
3274
3275         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3276
3277         while(len > 0) {
3278                 page = extent_buffer_page(eb, i);
3279                 WARN_ON(!PageUptodate(page));
3280
3281                 cur = min(len, PAGE_CACHE_SIZE - offset);
3282                 kaddr = kmap_atomic(page, KM_USER1);
3283                 memcpy(kaddr + offset, src, cur);
3284                 kunmap_atomic(kaddr, KM_USER1);
3285
3286                 src += cur;
3287                 len -= cur;
3288                 offset = 0;
3289                 i++;
3290         }
3291 }
3292 EXPORT_SYMBOL(write_extent_buffer);
3293
3294 void memset_extent_buffer(struct extent_buffer *eb, char c,
3295                           unsigned long start, unsigned long len)
3296 {
3297         size_t cur;
3298         size_t offset;
3299         struct page *page;
3300         char *kaddr;
3301         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3302         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3303
3304         WARN_ON(start > eb->len);
3305         WARN_ON(start + len > eb->start + eb->len);
3306
3307         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3308
3309         while(len > 0) {
3310                 page = extent_buffer_page(eb, i);
3311                 WARN_ON(!PageUptodate(page));
3312
3313                 cur = min(len, PAGE_CACHE_SIZE - offset);
3314                 kaddr = kmap_atomic(page, KM_USER0);
3315                 memset(kaddr + offset, c, cur);
3316                 kunmap_atomic(kaddr, KM_USER0);
3317
3318                 len -= cur;
3319                 offset = 0;
3320                 i++;
3321         }
3322 }
3323 EXPORT_SYMBOL(memset_extent_buffer);
3324
3325 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3326                         unsigned long dst_offset, unsigned long src_offset,
3327                         unsigned long len)
3328 {
3329         u64 dst_len = dst->len;
3330         size_t cur;
3331         size_t offset;
3332         struct page *page;
3333         char *kaddr;
3334         size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3335         unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3336
3337         WARN_ON(src->len != dst_len);
3338
3339         offset = (start_offset + dst_offset) &
3340                 ((unsigned long)PAGE_CACHE_SIZE - 1);
3341
3342         while(len > 0) {
3343                 page = extent_buffer_page(dst, i);
3344                 WARN_ON(!PageUptodate(page));
3345
3346                 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3347
3348                 kaddr = kmap_atomic(page, KM_USER0);
3349                 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3350                 kunmap_atomic(kaddr, KM_USER0);
3351
3352                 src_offset += cur;
3353                 len -= cur;
3354                 offset = 0;
3355                 i++;
3356         }
3357 }
3358 EXPORT_SYMBOL(copy_extent_buffer);
3359
3360 static void move_pages(struct page *dst_page, struct page *src_page,
3361                        unsigned long dst_off, unsigned long src_off,
3362                        unsigned long len)
3363 {
3364         char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3365         if (dst_page == src_page) {
3366                 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3367         } else {
3368                 char *src_kaddr = kmap_atomic(src_page, KM_USER1);
3369                 char *p = dst_kaddr + dst_off + len;
3370                 char *s = src_kaddr + src_off + len;
3371
3372                 while (len--)
3373                         *--p = *--s;
3374
3375                 kunmap_atomic(src_kaddr, KM_USER1);
3376         }
3377         kunmap_atomic(dst_kaddr, KM_USER0);
3378 }
3379
3380 static void copy_pages(struct page *dst_page, struct page *src_page,
3381                        unsigned long dst_off, unsigned long src_off,
3382                        unsigned long len)
3383 {
3384         char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3385         char *src_kaddr;
3386
3387         if (dst_page != src_page)
3388                 src_kaddr = kmap_atomic(src_page, KM_USER1);
3389         else
3390                 src_kaddr = dst_kaddr;
3391
3392         memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3393         kunmap_atomic(dst_kaddr, KM_USER0);
3394         if (dst_page != src_page)
3395                 kunmap_atomic(src_kaddr, KM_USER1);
3396 }
3397
3398 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3399                            unsigned long src_offset, unsigned long len)
3400 {
3401         size_t cur;
3402         size_t dst_off_in_page;
3403         size_t src_off_in_page;
3404         size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3405         unsigned long dst_i;
3406         unsigned long src_i;
3407
3408         if (src_offset + len > dst->len) {
3409                 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3410                        src_offset, len, dst->len);
3411                 BUG_ON(1);
3412         }
3413         if (dst_offset + len > dst->len) {
3414                 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3415                        dst_offset, len, dst->len);
3416                 BUG_ON(1);
3417         }
3418
3419         while(len > 0) {
3420                 dst_off_in_page = (start_offset + dst_offset) &
3421                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3422                 src_off_in_page = (start_offset + src_offset) &
3423                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3424
3425                 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3426                 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3427
3428                 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3429                                                src_off_in_page));
3430                 cur = min_t(unsigned long, cur,
3431                         (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3432
3433                 copy_pages(extent_buffer_page(dst, dst_i),
3434                            extent_buffer_page(dst, src_i),
3435                            dst_off_in_page, src_off_in_page, cur);
3436
3437                 src_offset += cur;
3438                 dst_offset += cur;
3439                 len -= cur;
3440         }
3441 }
3442 EXPORT_SYMBOL(memcpy_extent_buffer);
3443
3444 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3445                            unsigned long src_offset, unsigned long len)
3446 {
3447         size_t cur;
3448         size_t dst_off_in_page;
3449         size_t src_off_in_page;
3450         unsigned long dst_end = dst_offset + len - 1;
3451         unsigned long src_end = src_offset + len - 1;
3452         size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3453         unsigned long dst_i;
3454         unsigned long src_i;
3455
3456         if (src_offset + len > dst->len) {
3457                 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3458                        src_offset, len, dst->len);
3459                 BUG_ON(1);
3460         }
3461         if (dst_offset + len > dst->len) {
3462                 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3463                        dst_offset, len, dst->len);
3464                 BUG_ON(1);
3465         }
3466         if (dst_offset < src_offset) {
3467                 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3468                 return;
3469         }
3470         while(len > 0) {
3471                 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3472                 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3473
3474                 dst_off_in_page = (start_offset + dst_end) &
3475                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3476                 src_off_in_page = (start_offset + src_end) &
3477                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3478
3479                 cur = min_t(unsigned long, len, src_off_in_page + 1);
3480                 cur = min(cur, dst_off_in_page + 1);
3481                 move_pages(extent_buffer_page(dst, dst_i),
3482                            extent_buffer_page(dst, src_i),
3483                            dst_off_in_page - cur + 1,
3484                            src_off_in_page - cur + 1, cur);
3485
3486                 dst_end -= cur;
3487                 src_end -= cur;
3488                 len -= cur;
3489         }
3490 }
3491 EXPORT_SYMBOL(memmove_extent_buffer);
3492
3493 int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3494 {
3495         u64 start = page_offset(page);
3496         struct extent_buffer *eb;
3497         int ret = 1;
3498         unsigned long i;
3499         unsigned long num_pages;
3500
3501         spin_lock(&tree->buffer_lock);
3502         eb = buffer_search(tree, start);
3503         if (!eb)
3504                 goto out;
3505
3506         if (atomic_read(&eb->refs) > 1) {
3507                 ret = 0;
3508                 goto out;
3509         }
3510         /* at this point we can safely release the extent buffer */
3511         num_pages = num_extent_pages(eb->start, eb->len);
3512         for (i = 0; i < num_pages; i++) {
3513                 struct page *page = extent_buffer_page(eb, i);
3514                 page_cache_release(page);
3515         }
3516         rb_erase(&eb->rb_node, &tree->buffer);
3517         __free_extent_buffer(eb);
3518 out:
3519         spin_unlock(&tree->buffer_lock);
3520         return ret;
3521 }
3522 EXPORT_SYMBOL(try_release_extent_buffer);