git.oblomov.eu Git - 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 #include "compat.h"
  18 #include "ctree.h"
  19 #include "btrfs_inode.h"
  20
  21 /* temporary define until extent_map moves out of btrfs */
  22 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
  23                                        unsigned long extra_flags,
  24                                        void (*ctor)(void *, struct kmem_cache *,
  25                                                     unsigned long));
  26
  27 static struct kmem_cache *extent_state_cache;
  28 static struct kmem_cache *extent_buffer_cache;
  29
  30 static LIST_HEAD(buffers);
  31 static LIST_HEAD(states);
  32
  33 #define LEAK_DEBUG 0
  34 #ifdef LEAK_DEBUG
  35 static spinlock_t leak_lock = SPIN_LOCK_UNLOCKED;
  36 #endif
  37
  38 #define BUFFER_LRU_MAX 64
  39
  40 struct tree_entry {
  41         u64 start;
  42         u64 end;
  43         struct rb_node rb_node;
  44 };
  45
  46 struct extent_page_data {
  47         struct bio *bio;
  48         struct extent_io_tree *tree;
  49         get_extent_t *get_extent;
  50
  51         /* tells writepage not to lock the state bits for this range
  52          * it still does the unlocking
  53          */
  54         int extent_locked;
  55 };
  56
  57 int __init extent_io_init(void)
  58 {
  59         extent_state_cache = btrfs_cache_create("extent_state",
  60                                             sizeof(struct extent_state), 0,
  61                                             NULL);
  62         if (!extent_state_cache)
  63                 return -ENOMEM;
  64
  65         extent_buffer_cache = btrfs_cache_create("extent_buffers",
  66                                             sizeof(struct extent_buffer), 0,
  67                                             NULL);
  68         if (!extent_buffer_cache)
  69                 goto free_state_cache;
  70         return 0;
  71
  72 free_state_cache:
  73         kmem_cache_destroy(extent_state_cache);
  74         return -ENOMEM;
  75 }
  76
  77 void extent_io_exit(void)
  78 {
  79         struct extent_state *state;
  80         struct extent_buffer *eb;
  81
  82         while (!list_empty(&states)) {
  83                 state = list_entry(states.next, struct extent_state, leak_list);
  84                 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));
  85                 list_del(&state->leak_list);
  86                 kmem_cache_free(extent_state_cache, state);
  87
  88         }
  89
  90         while (!list_empty(&buffers)) {
  91                 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
  92                 printk("buffer leak start %Lu len %lu refs %d\n", eb->start, eb->len, atomic_read(&eb->refs));
  93                 list_del(&eb->leak_list);
  94                 kmem_cache_free(extent_buffer_cache, eb);
  95         }
  96         if (extent_state_cache)
  97                 kmem_cache_destroy(extent_state_cache);
  98         if (extent_buffer_cache)
  99                 kmem_cache_destroy(extent_buffer_cache);
 100 }
 101
 102 void extent_io_tree_init(struct extent_io_tree *tree,
 103                           struct address_space *mapping, gfp_t mask)
 104 {
 105         tree->state.rb_node = NULL;
 106         tree->buffer.rb_node = NULL;
 107         tree->ops = NULL;
 108         tree->dirty_bytes = 0;
 109         spin_lock_init(&tree->lock);
 110         spin_lock_init(&tree->buffer_lock);
 111         tree->mapping = mapping;
 112 }
 113 EXPORT_SYMBOL(extent_io_tree_init);
 114
 115 struct extent_state *alloc_extent_state(gfp_t mask)
 116 {
 117         struct extent_state *state;
 118 #ifdef LEAK_DEBUG
 119         unsigned long flags;
 120 #endif
 121
 122         state = kmem_cache_alloc(extent_state_cache, mask);
 123         if (!state)
 124                 return state;
 125         state->state = 0;
 126         state->private = 0;
 127         state->tree = NULL;
 128 #ifdef LEAK_DEBUG
 129         spin_lock_irqsave(&leak_lock, flags);
 130         list_add(&state->leak_list, &states);
 131         spin_unlock_irqrestore(&leak_lock, flags);
 132 #endif
 133         atomic_set(&state->refs, 1);
 134         init_waitqueue_head(&state->wq);
 135         return state;
 136 }
 137 EXPORT_SYMBOL(alloc_extent_state);
 138
 139 void free_extent_state(struct extent_state *state)
 140 {
 141         if (!state)
 142                 return;
 143         if (atomic_dec_and_test(&state->refs)) {
 144 #ifdef LEAK_DEBUG
 145                 unsigned long flags;
 146 #endif
 147                 WARN_ON(state->tree);
 148 #ifdef LEAK_DEBUG
 149                 spin_lock_irqsave(&leak_lock, flags);
 150                 list_del(&state->leak_list);
 151                 spin_unlock_irqrestore(&leak_lock, flags);
 152 #endif
 153                 kmem_cache_free(extent_state_cache, state);
 154         }
 155 }
 156 EXPORT_SYMBOL(free_extent_state);
 157
 158 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
 159                                    struct rb_node *node)
 160 {
 161         struct rb_node ** p = &root->rb_node;
 162         struct rb_node * parent = NULL;
 163         struct tree_entry *entry;
 164
 165         while(*p) {
 166                 parent = *p;
 167                 entry = rb_entry(parent, struct tree_entry, rb_node);
 168
 169                 if (offset < entry->start)
 170                         p = &(*p)->rb_left;
 171                 else if (offset > entry->end)
 172                         p = &(*p)->rb_right;
 173                 else
 174                         return parent;
 175         }
 176
 177         entry = rb_entry(node, struct tree_entry, rb_node);
 178         rb_link_node(node, parent, p);
 179         rb_insert_color(node, root);
 180         return NULL;
 181 }
 182
 183 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
 184                                      struct rb_node **prev_ret,
 185                                      struct rb_node **next_ret)
 186 {
 187         struct rb_root *root = &tree->state;
 188         struct rb_node * n = root->rb_node;
 189         struct rb_node *prev = NULL;
 190         struct rb_node *orig_prev = NULL;
 191         struct tree_entry *entry;
 192         struct tree_entry *prev_entry = NULL;
 193
 194         while(n) {
 195                 entry = rb_entry(n, struct tree_entry, rb_node);
 196                 prev = n;
 197                 prev_entry = entry;
 198
 199                 if (offset < entry->start)
 200                         n = n->rb_left;
 201                 else if (offset > entry->end)
 202                         n = n->rb_right;
 203                 else {
 204                         return n;
 205                 }
 206         }
 207
 208         if (prev_ret) {
 209                 orig_prev = prev;
 210                 while(prev && offset > prev_entry->end) {
 211                         prev = rb_next(prev);
 212                         prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 213                 }
 214                 *prev_ret = prev;
 215                 prev = orig_prev;
 216         }
 217
 218         if (next_ret) {
 219                 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 220                 while(prev && offset < prev_entry->start) {
 221                         prev = rb_prev(prev);
 222                         prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 223                 }
 224                 *next_ret = prev;
 225         }
 226         return NULL;
 227 }
 228
 229 static inline struct rb_node *tree_search(struct extent_io_tree *tree,
 230                                           u64 offset)
 231 {
 232         struct rb_node *prev = NULL;
 233         struct rb_node *ret;
 234
 235         ret = __etree_search(tree, offset, &prev, NULL);
 236         if (!ret) {
 237                 return prev;
 238         }
 239         return ret;
 240 }
 241
 242 static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree,
 243                                           u64 offset, struct rb_node *node)
 244 {
 245         struct rb_root *root = &tree->buffer;
 246         struct rb_node ** p = &root->rb_node;
 247         struct rb_node * parent = NULL;
 248         struct extent_buffer *eb;
 249
 250         while(*p) {
 251                 parent = *p;
 252                 eb = rb_entry(parent, struct extent_buffer, rb_node);
 253
 254                 if (offset < eb->start)
 255                         p = &(*p)->rb_left;
 256                 else if (offset > eb->start)
 257                         p = &(*p)->rb_right;
 258                 else
 259                         return eb;
 260         }
 261
 262         rb_link_node(node, parent, p);
 263         rb_insert_color(node, root);
 264         return NULL;
 265 }
 266
 267 static struct extent_buffer *buffer_search(struct extent_io_tree *tree,
 268                                            u64 offset)
 269 {
 270         struct rb_root *root = &tree->buffer;
 271         struct rb_node * n = root->rb_node;
 272         struct extent_buffer *eb;
 273
 274         while(n) {
 275                 eb = rb_entry(n, struct extent_buffer, rb_node);
 276                 if (offset < eb->start)
 277                         n = n->rb_left;
 278                 else if (offset > eb->start)
 279                         n = n->rb_right;
 280                 else
 281                         return eb;
 282         }
 283         return NULL;
 284 }
 285
 286 /*
 287  * utility function to look for merge candidates inside a given range.
 288  * Any extents with matching state are merged together into a single
 289  * extent in the tree.  Extents with EXTENT_IO in their state field
 290  * are not merged because the end_io handlers need to be able to do
 291  * operations on them without sleeping (or doing allocations/splits).
 292  *
 293  * This should be called with the tree lock held.
 294  */
 295 static int merge_state(struct extent_io_tree *tree,
 296                        struct extent_state *state)
 297 {
 298         struct extent_state *other;
 299         struct rb_node *other_node;
 300
 301         if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
 302                 return 0;
 303
 304         other_node = rb_prev(&state->rb_node);
 305         if (other_node) {
 306                 other = rb_entry(other_node, struct extent_state, rb_node);
 307                 if (other->end == state->start - 1 &&
 308                     other->state == state->state) {
 309                         state->start = other->start;
 310                         other->tree = NULL;
 311                         rb_erase(&other->rb_node, &tree->state);
 312                         free_extent_state(other);
 313                 }
 314         }
 315         other_node = rb_next(&state->rb_node);
 316         if (other_node) {
 317                 other = rb_entry(other_node, struct extent_state, rb_node);
 318                 if (other->start == state->end + 1 &&
 319                     other->state == state->state) {
 320                         other->start = state->start;
 321                         state->tree = NULL;
 322                         rb_erase(&state->rb_node, &tree->state);
 323                         free_extent_state(state);
 324                 }
 325         }
 326         return 0;
 327 }
 328
 329 static void set_state_cb(struct extent_io_tree *tree,
 330                          struct extent_state *state,
 331                          unsigned long bits)
 332 {
 333         if (tree->ops && tree->ops->set_bit_hook) {
 334                 tree->ops->set_bit_hook(tree->mapping->host, state->start,
 335                                         state->end, state->state, bits);
 336         }
 337 }
 338
 339 static void clear_state_cb(struct extent_io_tree *tree,
 340                            struct extent_state *state,
 341                            unsigned long bits)
 342 {
 343         if (tree->ops && tree->ops->set_bit_hook) {
 344                 tree->ops->clear_bit_hook(tree->mapping->host, state->start,
 345                                           state->end, state->state, bits);
 346         }
 347 }
 348
 349 /*
 350  * insert an extent_state struct into the tree.  'bits' are set on the
 351  * struct before it is inserted.
 352  *
 353  * This may return -EEXIST if the extent is already there, in which case the
 354  * state struct is freed.
 355  *
 356  * The tree lock is not taken internally.  This is a utility function and
 357  * probably isn't what you want to call (see set/clear_extent_bit).
 358  */
 359 static int insert_state(struct extent_io_tree *tree,
 360                         struct extent_state *state, u64 start, u64 end,
 361                         int bits)
 362 {
 363         struct rb_node *node;
 364
 365         if (end < start) {
 366                 printk("end < start %Lu %Lu\n", end, start);
 367                 WARN_ON(1);
 368         }
 369         if (bits & EXTENT_DIRTY)
 370                 tree->dirty_bytes += end - start + 1;
 371         set_state_cb(tree, state, bits);
 372         state->state |= bits;
 373         state->start = start;
 374         state->end = end;
 375         node = tree_insert(&tree->state, end, &state->rb_node);
 376         if (node) {
 377                 struct extent_state *found;
 378                 found = rb_entry(node, struct extent_state, rb_node);
 379                 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
 380                 free_extent_state(state);
 381                 return -EEXIST;
 382         }
 383         state->tree = tree;
 384         merge_state(tree, state);
 385         return 0;
 386 }
 387
 388 /*
 389  * split a given extent state struct in two, inserting the preallocated
 390  * struct 'prealloc' as the newly created second half.  'split' indicates an
 391  * offset inside 'orig' where it should be split.
 392  *
 393  * Before calling,
 394  * the tree has 'orig' at [orig->start, orig->end].  After calling, there
 395  * are two extent state structs in the tree:
 396  * prealloc: [orig->start, split - 1]
 397  * orig: [ split, orig->end ]
 398  *
 399  * The tree locks are not taken by this function. They need to be held
 400  * by the caller.
 401  */
 402 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 403                        struct extent_state *prealloc, u64 split)
 404 {
 405         struct rb_node *node;
 406         prealloc->start = orig->start;
 407         prealloc->end = split - 1;
 408         prealloc->state = orig->state;
 409         orig->start = split;
 410
 411         node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
 412         if (node) {
 413                 struct extent_state *found;
 414                 found = rb_entry(node, struct extent_state, rb_node);
 415                 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
 416                 free_extent_state(prealloc);
 417                 return -EEXIST;
 418         }
 419         prealloc->tree = tree;
 420         return 0;
 421 }
 422
 423 /*
 424  * utility function to clear some bits in an extent state struct.
 425  * it will optionally wake up any one waiting on this state (wake == 1), or
 426  * forcibly remove the state from the tree (delete == 1).
 427  *
 428  * If no bits are set on the state struct after clearing things, the
 429  * struct is freed and removed from the tree
 430  */
 431 static int clear_state_bit(struct extent_io_tree *tree,
 432                             struct extent_state *state, int bits, int wake,
 433                             int delete)
 434 {
 435         int ret = state->state & bits;
 436
 437         if ((bits & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
 438                 u64 range = state->end - state->start + 1;
 439                 WARN_ON(range > tree->dirty_bytes);
 440                 tree->dirty_bytes -= range;
 441         }
 442         clear_state_cb(tree, state, bits);
 443         state->state &= ~bits;
 444         if (wake)
 445                 wake_up(&state->wq);
 446         if (delete || state->state == 0) {
 447                 if (state->tree) {
 448                         clear_state_cb(tree, state, state->state);
 449                         rb_erase(&state->rb_node, &tree->state);
 450                         state->tree = NULL;
 451                         free_extent_state(state);
 452                 } else {
 453                         WARN_ON(1);
 454                 }
 455         } else {
 456                 merge_state(tree, state);
 457         }
 458         return ret;
 459 }
 460
 461 /*
 462  * clear some bits on a range in the tree.  This may require splitting
 463  * or inserting elements in the tree, so the gfp mask is used to
 464  * indicate which allocations or sleeping are allowed.
 465  *
 466  * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
 467  * the given range from the tree regardless of state (ie for truncate).
 468  *
 469  * the range [start, end] is inclusive.
 470  *
 471  * This takes the tree lock, and returns < 0 on error, > 0 if any of the
 472  * bits were already set, or zero if none of the bits were already set.
 473  */
 474 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 475                      int bits, int wake, int delete, gfp_t mask)
 476 {
 477         struct extent_state *state;
 478         struct extent_state *prealloc = NULL;
 479         struct rb_node *node;
 480         unsigned long flags;
 481         int err;
 482         int set = 0;
 483
 484 again:
 485         if (!prealloc && (mask & __GFP_WAIT)) {
 486                 prealloc = alloc_extent_state(mask);
 487                 if (!prealloc)
 488                         return -ENOMEM;
 489         }
 490
 491         spin_lock_irqsave(&tree->lock, flags);
 492         /*
 493          * this search will find the extents that end after
 494          * our range starts
 495          */
 496         node = tree_search(tree, start);
 497         if (!node)
 498                 goto out;
 499         state = rb_entry(node, struct extent_state, rb_node);
 500         if (state->start > end)
 501                 goto out;
 502         WARN_ON(state->end < start);
 503
 504         /*
 505          *     | ---- desired range ---- |
 506          *  | state | or
 507          *  | ------------- state -------------- |
 508          *
 509          * We need to split the extent we found, and may flip
 510          * bits on second half.
 511          *
 512          * If the extent we found extends past our range, we
 513          * just split and search again.  It'll get split again
 514          * the next time though.
 515          *
 516          * If the extent we found is inside our range, we clear
 517          * the desired bit on it.
 518          */
 519
 520         if (state->start < start) {
 521                 if (!prealloc)
 522                         prealloc = alloc_extent_state(GFP_ATOMIC);
 523                 err = split_state(tree, state, prealloc, start);
 524                 BUG_ON(err == -EEXIST);
 525                 prealloc = NULL;
 526                 if (err)
 527                         goto out;
 528                 if (state->end <= end) {
 529                         start = state->end + 1;
 530                         set |= clear_state_bit(tree, state, bits,
 531                                         wake, delete);
 532                 } else {
 533                         start = state->start;
 534                 }
 535                 goto search_again;
 536         }
 537         /*
 538          * | ---- desired range ---- |
 539          *                        | state |
 540          * We need to split the extent, and clear the bit
 541          * on the first half
 542          */
 543         if (state->start <= end && state->end > end) {
 544                 if (!prealloc)
 545                         prealloc = alloc_extent_state(GFP_ATOMIC);
 546                 err = split_state(tree, state, prealloc, end + 1);
 547                 BUG_ON(err == -EEXIST);
 548
 549                 if (wake)
 550                         wake_up(&state->wq);
 551                 set |= clear_state_bit(tree, prealloc, bits,
 552                                        wake, delete);
 553                 prealloc = NULL;
 554                 goto out;
 555         }
 556
 557         start = state->end + 1;
 558         set |= clear_state_bit(tree, state, bits, wake, delete);
 559         goto search_again;
 560
 561 out:
 562         spin_unlock_irqrestore(&tree->lock, flags);
 563         if (prealloc)
 564                 free_extent_state(prealloc);
 565
 566         return set;
 567
 568 search_again:
 569         if (start > end)
 570                 goto out;
 571         spin_unlock_irqrestore(&tree->lock, flags);
 572         if (mask & __GFP_WAIT)
 573                 cond_resched();
 574         goto again;
 575 }
 576 EXPORT_SYMBOL(clear_extent_bit);
 577
 578 static int wait_on_state(struct extent_io_tree *tree,
 579                          struct extent_state *state)
 580 {
 581         DEFINE_WAIT(wait);
 582         prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
 583         spin_unlock_irq(&tree->lock);
 584         schedule();
 585         spin_lock_irq(&tree->lock);
 586         finish_wait(&state->wq, &wait);
 587         return 0;
 588 }
 589
 590 /*
 591  * waits for one or more bits to clear on a range in the state tree.
 592  * The range [start, end] is inclusive.
 593  * The tree lock is taken by this function
 594  */
 595 int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
 596 {
 597         struct extent_state *state;
 598         struct rb_node *node;
 599
 600         spin_lock_irq(&tree->lock);
 601 again:
 602         while (1) {
 603                 /*
 604                  * this search will find all the extents that end after
 605                  * our range starts
 606                  */
 607                 node = tree_search(tree, start);
 608                 if (!node)
 609                         break;
 610
 611                 state = rb_entry(node, struct extent_state, rb_node);
 612
 613                 if (state->start > end)
 614                         goto out;
 615
 616                 if (state->state & bits) {
 617                         start = state->start;
 618                         atomic_inc(&state->refs);
 619                         wait_on_state(tree, state);
 620                         free_extent_state(state);
 621                         goto again;
 622                 }
 623                 start = state->end + 1;
 624
 625                 if (start > end)
 626                         break;
 627
 628                 if (need_resched()) {
 629                         spin_unlock_irq(&tree->lock);
 630                         cond_resched();
 631                         spin_lock_irq(&tree->lock);
 632                 }
 633         }
 634 out:
 635         spin_unlock_irq(&tree->lock);
 636         return 0;
 637 }
 638 EXPORT_SYMBOL(wait_extent_bit);
 639
 640 static void set_state_bits(struct extent_io_tree *tree,
 641                            struct extent_state *state,
 642                            int bits)
 643 {
 644         if ((bits & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
 645                 u64 range = state->end - state->start + 1;
 646                 tree->dirty_bytes += range;
 647         }
 648         set_state_cb(tree, state, bits);
 649         state->state |= bits;
 650 }
 651
 652 /*
 653  * set some bits on a range in the tree.  This may require allocations
 654  * or sleeping, so the gfp mask is used to indicate what is allowed.
 655  *
 656  * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
 657  * range already has the desired bits set.  The start of the existing
 658  * range is returned in failed_start in this case.
 659  *
 660  * [start, end] is inclusive
 661  * This takes the tree lock.
 662  */
 663 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits,
 664                    int exclusive, u64 *failed_start, gfp_t mask)
 665 {
 666         struct extent_state *state;
 667         struct extent_state *prealloc = NULL;
 668         struct rb_node *node;
 669         unsigned long flags;
 670         int err = 0;
 671         int set;
 672         u64 last_start;
 673         u64 last_end;
 674 again:
 675         if (!prealloc && (mask & __GFP_WAIT)) {
 676                 prealloc = alloc_extent_state(mask);
 677                 if (!prealloc)
 678                         return -ENOMEM;
 679         }
 680
 681         spin_lock_irqsave(&tree->lock, flags);
 682         /*
 683          * this search will find all the extents that end after
 684          * our range starts.
 685          */
 686         node = tree_search(tree, start);
 687         if (!node) {
 688                 err = insert_state(tree, prealloc, start, end, bits);
 689                 prealloc = NULL;
 690                 BUG_ON(err == -EEXIST);
 691                 goto out;
 692         }
 693
 694         state = rb_entry(node, struct extent_state, rb_node);
 695         last_start = state->start;
 696         last_end = state->end;
 697
 698         /*
 699          * | ---- desired range ---- |
 700          * | state |
 701          *
 702          * Just lock what we found and keep going
 703          */
 704         if (state->start == start && state->end <= end) {
 705                 set = state->state & bits;
 706                 if (set && exclusive) {
 707                         *failed_start = state->start;
 708                         err = -EEXIST;
 709                         goto out;
 710                 }
 711                 set_state_bits(tree, state, bits);
 712                 start = state->end + 1;
 713                 merge_state(tree, state);
 714                 goto search_again;
 715         }
 716
 717         /*
 718          *     | ---- desired range ---- |
 719          * | state |
 720          *   or
 721          * | ------------- state -------------- |
 722          *
 723          * We need to split the extent we found, and may flip bits on
 724          * second half.
 725          *
 726          * If the extent we found extends past our
 727          * range, we just split and search again.  It'll get split
 728          * again the next time though.
 729          *
 730          * If the extent we found is inside our range, we set the
 731          * desired bit on it.
 732          */
 733         if (state->start < start) {
 734                 set = state->state & bits;
 735                 if (exclusive && set) {
 736                         *failed_start = start;
 737                         err = -EEXIST;
 738                         goto out;
 739                 }
 740                 err = split_state(tree, state, prealloc, start);
 741                 BUG_ON(err == -EEXIST);
 742                 prealloc = NULL;
 743                 if (err)
 744                         goto out;
 745                 if (state->end <= end) {
 746                         set_state_bits(tree, state, bits);
 747                         start = state->end + 1;
 748                         merge_state(tree, state);
 749                 } else {
 750                         start = state->start;
 751                 }
 752                 goto search_again;
 753         }
 754         /*
 755          * | ---- desired range ---- |
 756          *     | state | or               | state |
 757          *
 758          * There's a hole, we need to insert something in it and
 759          * ignore the extent we found.
 760          */
 761         if (state->start > start) {
 762                 u64 this_end;
 763                 if (end < last_start)
 764                         this_end = end;
 765                 else
 766                         this_end = last_start -1;
 767                 err = insert_state(tree, prealloc, start, this_end,
 768                                    bits);
 769                 prealloc = NULL;
 770                 BUG_ON(err == -EEXIST);
 771                 if (err)
 772                         goto out;
 773                 start = this_end + 1;
 774                 goto search_again;
 775         }
 776         /*
 777          * | ---- desired range ---- |
 778          *                        | state |
 779          * We need to split the extent, and set the bit
 780          * on the first half
 781          */
 782         if (state->start <= end && state->end > end) {
 783                 set = state->state & bits;
 784                 if (exclusive && set) {
 785                         *failed_start = start;
 786                         err = -EEXIST;
 787                         goto out;
 788                 }
 789                 err = split_state(tree, state, prealloc, end + 1);
 790                 BUG_ON(err == -EEXIST);
 791
 792                 set_state_bits(tree, prealloc, bits);
 793                 merge_state(tree, prealloc);
 794                 prealloc = NULL;
 795                 goto out;
 796         }
 797
 798         goto search_again;
 799
 800 out:
 801         spin_unlock_irqrestore(&tree->lock, flags);
 802         if (prealloc)
 803                 free_extent_state(prealloc);
 804
 805         return err;
 806
 807 search_again:
 808         if (start > end)
 809                 goto out;
 810         spin_unlock_irqrestore(&tree->lock, flags);
 811         if (mask & __GFP_WAIT)
 812                 cond_resched();
 813         goto again;
 814 }
 815 EXPORT_SYMBOL(set_extent_bit);
 816
 817 /* wrappers around set/clear extent bit */
 818 int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
 819                      gfp_t mask)
 820 {
 821         return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
 822                               mask);
 823 }
 824 EXPORT_SYMBOL(set_extent_dirty);
 825
 826 int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
 827                        gfp_t mask)
 828 {
 829         return set_extent_bit(tree, start, end, EXTENT_ORDERED, 0, NULL, mask);
 830 }
 831 EXPORT_SYMBOL(set_extent_ordered);
 832
 833 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 834                     int bits, gfp_t mask)
 835 {
 836         return set_extent_bit(tree, start, end, bits, 0, NULL,
 837                               mask);
 838 }
 839 EXPORT_SYMBOL(set_extent_bits);
 840
 841 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 842                       int bits, gfp_t mask)
 843 {
 844         return clear_extent_bit(tree, start, end, bits, 0, 0, mask);
 845 }
 846 EXPORT_SYMBOL(clear_extent_bits);
 847
 848 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
 849                      gfp_t mask)
 850 {
 851         return set_extent_bit(tree, start, end,
 852                               EXTENT_DELALLOC | EXTENT_DIRTY,
 853                               0, NULL, mask);
 854 }
 855 EXPORT_SYMBOL(set_extent_delalloc);
 856
 857 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
 858                        gfp_t mask)
 859 {
 860         return clear_extent_bit(tree, start, end,
 861                                 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, mask);
 862 }
 863 EXPORT_SYMBOL(clear_extent_dirty);
 864
 865 int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
 866                          gfp_t mask)
 867 {
 868         return clear_extent_bit(tree, start, end, EXTENT_ORDERED, 1, 0, mask);
 869 }
 870 EXPORT_SYMBOL(clear_extent_ordered);
 871
 872 int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
 873                      gfp_t mask)
 874 {
 875         return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
 876                               mask);
 877 }
 878 EXPORT_SYMBOL(set_extent_new);
 879
 880 int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
 881                        gfp_t mask)
 882 {
 883         return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
 884 }
 885 EXPORT_SYMBOL(clear_extent_new);
 886
 887 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
 888                         gfp_t mask)
 889 {
 890         return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
 891                               mask);
 892 }
 893 EXPORT_SYMBOL(set_extent_uptodate);
 894
 895 int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
 896                           gfp_t mask)
 897 {
 898         return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
 899 }
 900 EXPORT_SYMBOL(clear_extent_uptodate);
 901
 902 int set_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
 903                          gfp_t mask)
 904 {
 905         return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
 906                               0, NULL, mask);
 907 }
 908 EXPORT_SYMBOL(set_extent_writeback);
 909
 910 int clear_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
 911                            gfp_t mask)
 912 {
 913         return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
 914 }
 915 EXPORT_SYMBOL(clear_extent_writeback);
 916
 917 int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
 918 {
 919         return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
 920 }
 921 EXPORT_SYMBOL(wait_on_extent_writeback);
 922
 923 /*
 924  * either insert or lock state struct between start and end use mask to tell
 925  * us if waiting is desired.
 926  */
 927 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
 928 {
 929         int err;
 930         u64 failed_start;
 931         while (1) {
 932                 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
 933                                      &failed_start, mask);
 934                 if (err == -EEXIST && (mask & __GFP_WAIT)) {
 935                         wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
 936                         start = failed_start;
 937                 } else {
 938                         break;
 939                 }
 940                 WARN_ON(start > end);
 941         }
 942         return err;
 943 }
 944 EXPORT_SYMBOL(lock_extent);
 945
 946 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
 947                     gfp_t mask)
 948 {
 949         int err;
 950         u64 failed_start;
 951
 952         err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
 953                              &failed_start, mask);
 954         if (err == -EEXIST) {
 955                 if (failed_start > start)
 956                         clear_extent_bit(tree, start, failed_start - 1,
 957                                          EXTENT_LOCKED, 1, 0, mask);
 958                 return 0;
 959         }
 960         return 1;
 961 }
 962 EXPORT_SYMBOL(try_lock_extent);
 963
 964 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
 965                   gfp_t mask)
 966 {
 967         return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
 968 }
 969 EXPORT_SYMBOL(unlock_extent);
 970
 971 /*
 972  * helper function to set pages and extents in the tree dirty
 973  */
 974 int set_range_dirty(struct extent_io_tree *tree, u64 start, u64 end)
 975 {
 976         unsigned long index = start >> PAGE_CACHE_SHIFT;
 977         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
 978         struct page *page;
 979
 980         while (index <= end_index) {
 981                 page = find_get_page(tree->mapping, index);
 982                 BUG_ON(!page);
 983                 __set_page_dirty_nobuffers(page);
 984                 page_cache_release(page);
 985                 index++;
 986         }
 987         set_extent_dirty(tree, start, end, GFP_NOFS);
 988         return 0;
 989 }
 990 EXPORT_SYMBOL(set_range_dirty);
 991
 992 /*
 993  * helper function to set both pages and extents in the tree writeback
 994  */
 995 int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
 996 {
 997         unsigned long index = start >> PAGE_CACHE_SHIFT;
 998         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
 999         struct page *page;
1000
1001         while (index <= end_index) {
1002                 page = find_get_page(tree->mapping, index);
1003                 BUG_ON(!page);
1004                 set_page_writeback(page);
1005                 page_cache_release(page);
1006                 index++;
1007         }
1008         set_extent_writeback(tree, start, end, GFP_NOFS);
1009         return 0;
1010 }
1011 EXPORT_SYMBOL(set_range_writeback);
1012
1013 /*
1014  * find the first offset in the io tree with 'bits' set. zero is
1015  * returned if we find something, and *start_ret and *end_ret are
1016  * set to reflect the state struct that was found.
1017  *
1018  * If nothing was found, 1 is returned, < 0 on error
1019  */
1020 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1021                           u64 *start_ret, u64 *end_ret, int bits)
1022 {
1023         struct rb_node *node;
1024         struct extent_state *state;
1025         int ret = 1;
1026
1027         spin_lock_irq(&tree->lock);
1028         /*
1029          * this search will find all the extents that end after
1030          * our range starts.
1031          */
1032         node = tree_search(tree, start);
1033         if (!node) {
1034                 goto out;
1035         }
1036
1037         while(1) {
1038                 state = rb_entry(node, struct extent_state, rb_node);
1039                 if (state->end >= start && (state->state & bits)) {
1040                         *start_ret = state->start;
1041                         *end_ret = state->end;
1042                         ret = 0;
1043                         break;
1044                 }
1045                 node = rb_next(node);
1046                 if (!node)
1047                         break;
1048         }
1049 out:
1050         spin_unlock_irq(&tree->lock);
1051         return ret;
1052 }
1053 EXPORT_SYMBOL(find_first_extent_bit);
1054
1055 /* find the first state struct with 'bits' set after 'start', and
1056  * return it.  tree->lock must be held.  NULL will returned if
1057  * nothing was found after 'start'
1058  */
1059 struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1060                                                  u64 start, int bits)
1061 {
1062         struct rb_node *node;
1063         struct extent_state *state;
1064
1065         /*
1066          * this search will find all the extents that end after
1067          * our range starts.
1068          */
1069         node = tree_search(tree, start);
1070         if (!node) {
1071                 goto out;
1072         }
1073
1074         while(1) {
1075                 state = rb_entry(node, struct extent_state, rb_node);
1076                 if (state->end >= start && (state->state & bits)) {
1077                         return state;
1078                 }
1079                 node = rb_next(node);
1080                 if (!node)
1081                         break;
1082         }
1083 out:
1084         return NULL;
1085 }
1086 EXPORT_SYMBOL(find_first_extent_bit_state);
1087
1088 /*
1089  * find a contiguous range of bytes in the file marked as delalloc, not
1090  * more than 'max_bytes'.  start and end are used to return the range,
1091  *
1092  * 1 is returned if we find something, 0 if nothing was in the tree
1093  */
1094 static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1095                                         u64 *start, u64 *end, u64 max_bytes)
1096 {
1097         struct rb_node *node;
1098         struct extent_state *state;
1099         u64 cur_start = *start;
1100         u64 found = 0;
1101         u64 total_bytes = 0;
1102
1103         spin_lock_irq(&tree->lock);
1104
1105         /*
1106          * this search will find all the extents that end after
1107          * our range starts.
1108          */
1109         node = tree_search(tree, cur_start);
1110         if (!node) {
1111                 if (!found)
1112                         *end = (u64)-1;
1113                 goto out;
1114         }
1115
1116         while(1) {
1117                 state = rb_entry(node, struct extent_state, rb_node);
1118                 if (found && (state->start != cur_start ||
1119                               (state->state & EXTENT_BOUNDARY))) {
1120                         goto out;
1121                 }
1122                 if (!(state->state & EXTENT_DELALLOC)) {
1123                         if (!found)
1124                                 *end = state->end;
1125                         goto out;
1126                 }
1127                 if (!found)
1128                         *start = state->start;
1129                 found++;
1130                 *end = state->end;
1131                 cur_start = state->end + 1;
1132                 node = rb_next(node);
1133                 if (!node)
1134                         break;
1135                 total_bytes += state->end - state->start + 1;
1136                 if (total_bytes >= max_bytes)
1137                         break;
1138         }
1139 out:
1140         spin_unlock_irq(&tree->lock);
1141         return found;
1142 }
1143
1144 static noinline int __unlock_for_delalloc(struct inode *inode,
1145                                           struct page *locked_page,
1146                                           u64 start, u64 end)
1147 {
1148         int ret;
1149         struct page *pages[16];
1150         unsigned long index = start >> PAGE_CACHE_SHIFT;
1151         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1152         unsigned long nr_pages = end_index - index + 1;
1153         int i;
1154
1155         if (index == locked_page->index && end_index == index)
1156                 return 0;
1157
1158         while(nr_pages > 0) {
1159                 ret = find_get_pages_contig(inode->i_mapping, index,
1160                                      min(nr_pages, ARRAY_SIZE(pages)), pages);
1161                 for (i = 0; i < ret; i++) {
1162                         if (pages[i] != locked_page)
1163                                 unlock_page(pages[i]);
1164                         page_cache_release(pages[i]);
1165                 }
1166                 nr_pages -= ret;
1167                 index += ret;
1168                 cond_resched();
1169         }
1170         return 0;
1171 }
1172
1173 static noinline int lock_delalloc_pages(struct inode *inode,
1174                                         struct page *locked_page,
1175                                         u64 delalloc_start,
1176                                         u64 delalloc_end)
1177 {
1178         unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1179         unsigned long start_index = index;
1180         unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1181         unsigned long pages_locked = 0;
1182         struct page *pages[16];
1183         unsigned long nrpages;
1184         int ret;
1185         int i;
1186
1187         /* the caller is responsible for locking the start index */
1188         if (index == locked_page->index && index == end_index)
1189                 return 0;
1190
1191         /* skip the page at the start index */
1192         nrpages = end_index - index + 1;
1193         while(nrpages > 0) {
1194                 ret = find_get_pages_contig(inode->i_mapping, index,
1195                                      min(nrpages, ARRAY_SIZE(pages)), pages);
1196                 if (ret == 0) {
1197                         ret = -EAGAIN;
1198                         goto done;
1199                 }
1200                 /* now we have an array of pages, lock them all */
1201                 for (i = 0; i < ret; i++) {
1202                         /*
1203                          * the caller is taking responsibility for
1204                          * locked_page
1205                          */
1206                         if (pages[i] != locked_page) {
1207                                 lock_page(pages[i]);
1208                                 if (!PageDirty(pages[i]) ||
1209                                     pages[i]->mapping != inode->i_mapping) {
1210                                         ret = -EAGAIN;
1211                                         unlock_page(pages[i]);
1212                                         page_cache_release(pages[i]);
1213                                         goto done;
1214                                 }
1215                         }
1216                         page_cache_release(pages[i]);
1217                         pages_locked++;
1218                 }
1219                 nrpages -= ret;
1220                 index += ret;
1221                 cond_resched();
1222         }
1223         ret = 0;
1224 done:
1225         if (ret && pages_locked) {
1226                 __unlock_for_delalloc(inode, locked_page,
1227                               delalloc_start,
1228                               ((u64)(start_index + pages_locked - 1)) <<
1229                               PAGE_CACHE_SHIFT);
1230         }
1231         return ret;
1232 }
1233
1234 /*
1235  * find a contiguous range of bytes in the file marked as delalloc, not
1236  * more than 'max_bytes'.  start and end are used to return the range,
1237  *
1238  * 1 is returned if we find something, 0 if nothing was in the tree
1239  */
1240 static noinline u64 find_lock_delalloc_range(struct inode *inode,
1241                                              struct extent_io_tree *tree,
1242                                              struct page *locked_page,
1243                                              u64 *start, u64 *end,
1244                                              u64 max_bytes)
1245 {
1246         u64 delalloc_start;
1247         u64 delalloc_end;
1248         u64 found;
1249         int ret;
1250         int loops = 0;
1251
1252 again:
1253         /* step one, find a bunch of delalloc bytes starting at start */
1254         delalloc_start = *start;
1255         delalloc_end = 0;
1256         found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1257                                     max_bytes);
1258         if (!found || delalloc_end <= *start) {
1259                 *start = delalloc_start;
1260                 *end = delalloc_end;
1261                 return found;
1262         }
1263
1264         /*
1265          * start comes from the offset of locked_page.  We have to lock
1266          * pages in order, so we can't process delalloc bytes before
1267          * locked_page
1268          */
1269         if (delalloc_start < *start) {
1270                 delalloc_start = *start;
1271         }
1272
1273         /*
1274          * make sure to limit the number of pages we try to lock down
1275          * if we're looping.
1276          */
1277         if (delalloc_end + 1 - delalloc_start > max_bytes && loops) {
1278                 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1279         }
1280         /* step two, lock all the pages after the page that has start */
1281         ret = lock_delalloc_pages(inode, locked_page,
1282                                   delalloc_start, delalloc_end);
1283         if (ret == -EAGAIN) {
1284                 /* some of the pages are gone, lets avoid looping by
1285                  * shortening the size of the delalloc range we're searching
1286                  */
1287                 if (!loops) {
1288                         unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1289                         max_bytes = PAGE_CACHE_SIZE - offset;
1290                         loops = 1;
1291                         goto again;
1292                 } else {
1293                         found = 0;
1294                         goto out_failed;
1295                 }
1296         }
1297         BUG_ON(ret);
1298
1299         /* step three, lock the state bits for the whole range */
1300         lock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
1301
1302         /* then test to make sure it is all still delalloc */
1303         ret = test_range_bit(tree, delalloc_start, delalloc_end,
1304                              EXTENT_DELALLOC, 1);
1305         if (!ret) {
1306                 unlock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
1307                 __unlock_for_delalloc(inode, locked_page,
1308                               delalloc_start, delalloc_end);
1309                 cond_resched();
1310                 goto again;
1311         }
1312         *start = delalloc_start;
1313         *end = delalloc_end;
1314 out_failed:
1315         return found;
1316 }
1317
1318 int extent_clear_unlock_delalloc(struct inode *inode,
1319                                 struct extent_io_tree *tree,
1320                                 u64 start, u64 end, struct page *locked_page,
1321                                 int unlock_pages,
1322                                 int clear_unlock,
1323                                 int clear_delalloc, int clear_dirty,
1324                                 int set_writeback,
1325                                 int end_writeback)
1326 {
1327         int ret;
1328         struct page *pages[16];
1329         unsigned long index = start >> PAGE_CACHE_SHIFT;
1330         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1331         unsigned long nr_pages = end_index - index + 1;
1332         int i;
1333         int clear_bits = 0;
1334
1335         if (clear_unlock)
1336                 clear_bits |= EXTENT_LOCKED;
1337         if (clear_dirty)
1338                 clear_bits |= EXTENT_DIRTY;
1339
1340         if (clear_delalloc)
1341                 clear_bits |= EXTENT_DELALLOC;
1342
1343         clear_extent_bit(tree, start, end, clear_bits, 1, 0, GFP_NOFS);
1344         if (!(unlock_pages || clear_dirty || set_writeback || end_writeback))
1345                 return 0;
1346
1347         while(nr_pages > 0) {
1348                 ret = find_get_pages_contig(inode->i_mapping, index,
1349                                      min(nr_pages, ARRAY_SIZE(pages)), pages);
1350                 for (i = 0; i < ret; i++) {
1351                         if (pages[i] == locked_page) {
1352                                 page_cache_release(pages[i]);
1353                                 continue;
1354                         }
1355                         if (clear_dirty)
1356                                 clear_page_dirty_for_io(pages[i]);
1357                         if (set_writeback)
1358                                 set_page_writeback(pages[i]);
1359                         if (end_writeback)
1360                                 end_page_writeback(pages[i]);
1361                         if (unlock_pages)
1362                                 unlock_page(pages[i]);
1363                         page_cache_release(pages[i]);
1364                 }
1365                 nr_pages -= ret;
1366                 index += ret;
1367                 cond_resched();
1368         }
1369         return 0;
1370 }
1371 EXPORT_SYMBOL(extent_clear_unlock_delalloc);
1372
1373 /*
1374  * count the number of bytes in the tree that have a given bit(s)
1375  * set.  This can be fairly slow, except for EXTENT_DIRTY which is
1376  * cached.  The total number found is returned.
1377  */
1378 u64 count_range_bits(struct extent_io_tree *tree,
1379                      u64 *start, u64 search_end, u64 max_bytes,
1380                      unsigned long bits)
1381 {
1382         struct rb_node *node;
1383         struct extent_state *state;
1384         u64 cur_start = *start;
1385         u64 total_bytes = 0;
1386         int found = 0;
1387
1388         if (search_end <= cur_start) {
1389                 printk("search_end %Lu start %Lu\n", search_end, cur_start);
1390                 WARN_ON(1);
1391                 return 0;
1392         }
1393
1394         spin_lock_irq(&tree->lock);
1395         if (cur_start == 0 && bits == EXTENT_DIRTY) {
1396                 total_bytes = tree->dirty_bytes;
1397                 goto out;
1398         }
1399         /*
1400          * this search will find all the extents that end after
1401          * our range starts.
1402          */
1403         node = tree_search(tree, cur_start);
1404         if (!node) {
1405                 goto out;
1406         }
1407
1408         while(1) {
1409                 state = rb_entry(node, struct extent_state, rb_node);
1410                 if (state->start > search_end)
1411                         break;
1412                 if (state->end >= cur_start && (state->state & bits)) {
1413                         total_bytes += min(search_end, state->end) + 1 -
1414                                        max(cur_start, state->start);
1415                         if (total_bytes >= max_bytes)
1416                                 break;
1417                         if (!found) {
1418                                 *start = state->start;
1419                                 found = 1;
1420                         }
1421                 }
1422                 node = rb_next(node);
1423                 if (!node)
1424                         break;
1425         }
1426 out:
1427         spin_unlock_irq(&tree->lock);
1428         return total_bytes;
1429 }
1430 /*
1431  * helper function to lock both pages and extents in the tree.
1432  * pages must be locked first.
1433  */
1434 int lock_range(struct extent_io_tree *tree, u64 start, u64 end)
1435 {
1436         unsigned long index = start >> PAGE_CACHE_SHIFT;
1437         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1438         struct page *page;
1439         int err;
1440
1441         while (index <= end_index) {
1442                 page = grab_cache_page(tree->mapping, index);
1443                 if (!page) {
1444                         err = -ENOMEM;
1445                         goto failed;
1446                 }
1447                 if (IS_ERR(page)) {
1448                         err = PTR_ERR(page);
1449                         goto failed;
1450                 }
1451                 index++;
1452         }
1453         lock_extent(tree, start, end, GFP_NOFS);
1454         return 0;
1455
1456 failed:
1457         /*
1458          * we failed above in getting the page at 'index', so we undo here
1459          * up to but not including the page at 'index'
1460          */
1461         end_index = index;
1462         index = start >> PAGE_CACHE_SHIFT;
1463         while (index < end_index) {
1464                 page = find_get_page(tree->mapping, index);
1465                 unlock_page(page);
1466                 page_cache_release(page);
1467                 index++;
1468         }
1469         return err;
1470 }
1471 EXPORT_SYMBOL(lock_range);
1472
1473 /*
1474  * helper function to unlock both pages and extents in the tree.
1475  */
1476 int unlock_range(struct extent_io_tree *tree, u64 start, u64 end)
1477 {
1478         unsigned long index = start >> PAGE_CACHE_SHIFT;
1479         unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1480         struct page *page;
1481
1482         while (index <= end_index) {
1483                 page = find_get_page(tree->mapping, index);
1484                 unlock_page(page);
1485                 page_cache_release(page);
1486                 index++;
1487         }
1488         unlock_extent(tree, start, end, GFP_NOFS);
1489         return 0;
1490 }
1491 EXPORT_SYMBOL(unlock_range);
1492
1493 /*
1494  * set the private field for a given byte offset in the tree.  If there isn't
1495  * an extent_state there already, this does nothing.
1496  */
1497 int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1498 {
1499         struct rb_node *node;
1500         struct extent_state *state;
1501         int ret = 0;
1502
1503         spin_lock_irq(&tree->lock);
1504         /*
1505          * this search will find all the extents that end after
1506          * our range starts.
1507          */
1508         node = tree_search(tree, start);
1509         if (!node) {
1510                 ret = -ENOENT;
1511                 goto out;
1512         }
1513         state = rb_entry(node, struct extent_state, rb_node);
1514         if (state->start != start) {
1515                 ret = -ENOENT;
1516                 goto out;
1517         }
1518         state->private = private;
1519 out:
1520         spin_unlock_irq(&tree->lock);
1521         return ret;
1522 }
1523
1524 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1525 {
1526         struct rb_node *node;
1527         struct extent_state *state;
1528         int ret = 0;
1529
1530         spin_lock_irq(&tree->lock);
1531         /*
1532          * this search will find all the extents that end after
1533          * our range starts.
1534          */
1535         node = tree_search(tree, start);
1536         if (!node) {
1537                 ret = -ENOENT;
1538                 goto out;
1539         }
1540         state = rb_entry(node, struct extent_state, rb_node);
1541         if (state->start != start) {
1542                 ret = -ENOENT;
1543                 goto out;
1544         }
1545         *private = state->private;
1546 out:
1547         spin_unlock_irq(&tree->lock);
1548         return ret;
1549 }
1550
1551 /*
1552  * searches a range in the state tree for a given mask.
1553  * If 'filled' == 1, this returns 1 only if every extent in the tree
1554  * has the bits set.  Otherwise, 1 is returned if any bit in the
1555  * range is found set.
1556  */
1557 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1558                    int bits, int filled)
1559 {
1560         struct extent_state *state = NULL;
1561         struct rb_node *node;
1562         int bitset = 0;
1563         unsigned long flags;
1564
1565         spin_lock_irqsave(&tree->lock, flags);
1566         node = tree_search(tree, start);
1567         while (node && start <= end) {
1568                 state = rb_entry(node, struct extent_state, rb_node);
1569
1570                 if (filled && state->start > start) {
1571                         bitset = 0;
1572                         break;
1573                 }
1574
1575                 if (state->start > end)
1576                         break;
1577
1578                 if (state->state & bits) {
1579                         bitset = 1;
1580                         if (!filled)
1581                                 break;
1582                 } else if (filled) {
1583                         bitset = 0;
1584                         break;
1585                 }
1586                 start = state->end + 1;
1587                 if (start > end)
1588                         break;
1589                 node = rb_next(node);
1590                 if (!node) {
1591                         if (filled)
1592                                 bitset = 0;
1593                         break;
1594                 }
1595         }
1596         spin_unlock_irqrestore(&tree->lock, flags);
1597         return bitset;
1598 }
1599 EXPORT_SYMBOL(test_range_bit);
1600
1601 /*
1602  * helper function to set a given page up to date if all the
1603  * extents in the tree for that page are up to date
1604  */
1605 static int check_page_uptodate(struct extent_io_tree *tree,
1606                                struct page *page)
1607 {
1608         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1609         u64 end = start + PAGE_CACHE_SIZE - 1;
1610         if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
1611                 SetPageUptodate(page);
1612         return 0;
1613 }
1614
1615 /*
1616  * helper function to unlock a page if all the extents in the tree
1617  * for that page are unlocked
1618  */
1619 static int check_page_locked(struct extent_io_tree *tree,
1620                              struct page *page)
1621 {
1622         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1623         u64 end = start + PAGE_CACHE_SIZE - 1;
1624         if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
1625                 unlock_page(page);
1626         return 0;
1627 }
1628
1629 /*
1630  * helper function to end page writeback if all the extents
1631  * in the tree for that page are done with writeback
1632  */
1633 static int check_page_writeback(struct extent_io_tree *tree,
1634                              struct page *page)
1635 {
1636         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1637         u64 end = start + PAGE_CACHE_SIZE - 1;
1638         if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
1639                 end_page_writeback(page);
1640         return 0;
1641 }
1642
1643 /* lots and lots of room for performance fixes in the end_bio funcs */
1644
1645 /*
1646  * after a writepage IO is done, we need to:
1647  * clear the uptodate bits on error
1648  * clear the writeback bits in the extent tree for this IO
1649  * end_page_writeback if the page has no more pending IO
1650  *
1651  * Scheduling is not allowed, so the extent state tree is expected
1652  * to have one and only one object corresponding to this IO.
1653  */
1654 static void end_bio_extent_writepage(struct bio *bio, int err)
1655 {
1656         int uptodate = err == 0;
1657         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1658         struct extent_io_tree *tree;
1659         u64 start;
1660         u64 end;
1661         int whole_page;
1662         int ret;
1663
1664         do {
1665                 struct page *page = bvec->bv_page;
1666                 tree = &BTRFS_I(page->mapping->host)->io_tree;
1667
1668                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1669                          bvec->bv_offset;
1670                 end = start + bvec->bv_len - 1;
1671
1672                 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1673                         whole_page = 1;
1674                 else
1675                         whole_page = 0;
1676
1677                 if (--bvec >= bio->bi_io_vec)
1678                         prefetchw(&bvec->bv_page->flags);
1679                 if (tree->ops && tree->ops->writepage_end_io_hook) {
1680                         ret = tree->ops->writepage_end_io_hook(page, start,
1681                                                        end, NULL, uptodate);
1682                         if (ret)
1683                                 uptodate = 0;
1684                 }
1685
1686                 if (!uptodate && tree->ops &&
1687                     tree->ops->writepage_io_failed_hook) {
1688                         ret = tree->ops->writepage_io_failed_hook(bio, page,
1689                                                          start, end, NULL);
1690                         if (ret == 0) {
1691                                 uptodate = (err == 0);
1692                                 continue;
1693                         }
1694                 }
1695
1696                 if (!uptodate) {
1697                         clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
1698                         ClearPageUptodate(page);
1699                         SetPageError(page);
1700                 }
1701
1702                 clear_extent_writeback(tree, start, end, GFP_ATOMIC);
1703
1704                 if (whole_page)
1705                         end_page_writeback(page);
1706                 else
1707                         check_page_writeback(tree, page);
1708         } while (bvec >= bio->bi_io_vec);
1709
1710         bio_put(bio);
1711 }
1712
1713 /*
1714  * after a readpage IO is done, we need to:
1715  * clear the uptodate bits on error
1716  * set the uptodate bits if things worked
1717  * set the page up to date if all extents in the tree are uptodate
1718  * clear the lock bit in the extent tree
1719  * unlock the page if there are no other extents locked for it
1720  *
1721  * Scheduling is not allowed, so the extent state tree is expected
1722  * to have one and only one object corresponding to this IO.
1723  */
1724 static void end_bio_extent_readpage(struct bio *bio, int err)
1725 {
1726         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1727         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1728         struct extent_io_tree *tree;
1729         u64 start;
1730         u64 end;
1731         int whole_page;
1732         int ret;
1733
1734         do {
1735                 struct page *page = bvec->bv_page;
1736                 tree = &BTRFS_I(page->mapping->host)->io_tree;
1737
1738                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1739                         bvec->bv_offset;
1740                 end = start + bvec->bv_len - 1;
1741
1742                 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1743                         whole_page = 1;
1744                 else
1745                         whole_page = 0;
1746
1747                 if (--bvec >= bio->bi_io_vec)
1748                         prefetchw(&bvec->bv_page->flags);
1749
1750                 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1751                         ret = tree->ops->readpage_end_io_hook(page, start, end,
1752                                                               NULL);
1753                         if (ret)
1754                                 uptodate = 0;
1755                 }
1756                 if (!uptodate && tree->ops &&
1757                     tree->ops->readpage_io_failed_hook) {
1758                         ret = tree->ops->readpage_io_failed_hook(bio, page,
1759                                                          start, end, NULL);
1760                         if (ret == 0) {
1761                                 uptodate =
1762                                         test_bit(BIO_UPTODATE, &bio->bi_flags);
1763                                 continue;
1764                         }
1765                 }
1766
1767                 if (uptodate) {
1768                         set_extent_uptodate(tree, start, end,
1769                                             GFP_ATOMIC);
1770                 }
1771                 unlock_extent(tree, start, end, GFP_ATOMIC);
1772
1773                 if (whole_page) {
1774                         if (uptodate) {
1775                                 SetPageUptodate(page);
1776                         } else {
1777                                 ClearPageUptodate(page);
1778                                 SetPageError(page);
1779                         }
1780                         unlock_page(page);
1781                 } else {
1782                         if (uptodate) {
1783                                 check_page_uptodate(tree, page);
1784                         } else {
1785                                 ClearPageUptodate(page);
1786                                 SetPageError(page);
1787                         }
1788                         check_page_locked(tree, page);
1789                 }
1790         } while (bvec >= bio->bi_io_vec);
1791
1792         bio_put(bio);
1793 }
1794
1795 /*
1796  * IO done from prepare_write is pretty simple, we just unlock
1797  * the structs in the extent tree when done, and set the uptodate bits
1798  * as appropriate.
1799  */
1800 static void end_bio_extent_preparewrite(struct bio *bio, int err)
1801 {
1802         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1803         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1804         struct extent_io_tree *tree;
1805         u64 start;
1806         u64 end;
1807
1808         do {
1809                 struct page *page = bvec->bv_page;
1810                 tree = &BTRFS_I(page->mapping->host)->io_tree;
1811
1812                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1813                         bvec->bv_offset;
1814                 end = start + bvec->bv_len - 1;
1815
1816                 if (--bvec >= bio->bi_io_vec)
1817                         prefetchw(&bvec->bv_page->flags);
1818
1819                 if (uptodate) {
1820                         set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1821                 } else {
1822                         ClearPageUptodate(page);
1823                         SetPageError(page);
1824                 }
1825
1826                 unlock_extent(tree, start, end, GFP_ATOMIC);
1827
1828         } while (bvec >= bio->bi_io_vec);
1829
1830         bio_put(bio);
1831 }
1832
1833 static struct bio *
1834 extent_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1835                  gfp_t gfp_flags)
1836 {
1837         struct bio *bio;
1838
1839         bio = bio_alloc(gfp_flags, nr_vecs);
1840
1841         if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1842                 while (!bio && (nr_vecs /= 2))
1843                         bio = bio_alloc(gfp_flags, nr_vecs);
1844         }
1845
1846         if (bio) {
1847                 bio->bi_size = 0;
1848                 bio->bi_bdev = bdev;
1849                 bio->bi_sector = first_sector;
1850         }
1851         return bio;
1852 }
1853
1854 static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1855                           unsigned long bio_flags)
1856 {
1857         int ret = 0;
1858         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1859         struct page *page = bvec->bv_page;
1860         struct extent_io_tree *tree = bio->bi_private;
1861         u64 start;
1862         u64 end;
1863
1864         start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1865         end = start + bvec->bv_len - 1;
1866
1867         bio->bi_private = NULL;
1868
1869         bio_get(bio);
1870
1871         if (tree->ops && tree->ops->submit_bio_hook)
1872                 tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1873                                            mirror_num, bio_flags);
1874         else
1875                 submit_bio(rw, bio);
1876         if (bio_flagged(bio, BIO_EOPNOTSUPP))
1877                 ret = -EOPNOTSUPP;
1878         bio_put(bio);
1879         return ret;
1880 }
1881
1882 static int submit_extent_page(int rw, struct extent_io_tree *tree,
1883                               struct page *page, sector_t sector,
1884                               size_t size, unsigned long offset,
1885                               struct block_device *bdev,
1886                               struct bio **bio_ret,
1887                               unsigned long max_pages,
1888                               bio_end_io_t end_io_func,
1889                               int mirror_num,
1890                               unsigned long prev_bio_flags,
1891                               unsigned long bio_flags)
1892 {
1893         int ret = 0;
1894         struct bio *bio;
1895         int nr;
1896         int contig = 0;
1897         int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1898         int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1899         size_t page_size = min(size, PAGE_CACHE_SIZE);
1900
1901         if (bio_ret && *bio_ret) {
1902                 bio = *bio_ret;
1903                 if (old_compressed)
1904                         contig = bio->bi_sector == sector;
1905                 else
1906                         contig = bio->bi_sector + (bio->bi_size >> 9) ==
1907                                 sector;
1908
1909                 if (prev_bio_flags != bio_flags || !contig ||
1910                     (tree->ops && tree->ops->merge_bio_hook &&
1911                      tree->ops->merge_bio_hook(page, offset, page_size, bio,
1912                                                bio_flags)) ||
1913                     bio_add_page(bio, page, page_size, offset) < page_size) {
1914                         ret = submit_one_bio(rw, bio, mirror_num,
1915                                              prev_bio_flags);
1916                         bio = NULL;
1917                 } else {
1918                         return 0;
1919                 }
1920         }
1921         if (this_compressed)
1922                 nr = BIO_MAX_PAGES;
1923         else
1924                 nr = bio_get_nr_vecs(bdev);
1925
1926         bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1927         if (!bio) {
1928                 printk("failed to allocate bio nr %d\n", nr);
1929         }
1930
1931         bio_add_page(bio, page, page_size, offset);
1932         bio->bi_end_io = end_io_func;
1933         bio->bi_private = tree;
1934
1935         if (bio_ret) {
1936                 *bio_ret = bio;
1937         } else {
1938                 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1939         }
1940
1941         return ret;
1942 }
1943
1944 void set_page_extent_mapped(struct page *page)
1945 {
1946         if (!PagePrivate(page)) {
1947                 SetPagePrivate(page);
1948                 page_cache_get(page);
1949                 set_page_private(page, EXTENT_PAGE_PRIVATE);
1950         }
1951 }
1952 EXPORT_SYMBOL(set_page_extent_mapped);
1953
1954 void set_page_extent_head(struct page *page, unsigned long len)
1955 {
1956         set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1957 }
1958
1959 /*
1960  * basic readpage implementation.  Locked extent state structs are inserted
1961  * into the tree that are removed when the IO is done (by the end_io
1962  * handlers)
1963  */
1964 static int __extent_read_full_page(struct extent_io_tree *tree,
1965                                    struct page *page,
1966                                    get_extent_t *get_extent,
1967                                    struct bio **bio, int mirror_num,
1968                                    unsigned long *bio_flags)
1969 {
1970         struct inode *inode = page->mapping->host;
1971         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1972         u64 page_end = start + PAGE_CACHE_SIZE - 1;
1973         u64 end;
1974         u64 cur = start;
1975         u64 extent_offset;
1976         u64 last_byte = i_size_read(inode);
1977         u64 block_start;
1978         u64 cur_end;
1979         sector_t sector;
1980         struct extent_map *em;
1981         struct block_device *bdev;
1982         int ret;
1983         int nr = 0;
1984         size_t page_offset = 0;
1985         size_t iosize;
1986         size_t disk_io_size;
1987         size_t blocksize = inode->i_sb->s_blocksize;
1988         unsigned long this_bio_flag = 0;
1989
1990         set_page_extent_mapped(page);
1991
1992         end = page_end;
1993         lock_extent(tree, start, end, GFP_NOFS);
1994
1995         if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1996                 char *userpage;
1997                 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1998
1999                 if (zero_offset) {
2000                         iosize = PAGE_CACHE_SIZE - zero_offset;
2001                         userpage = kmap_atomic(page, KM_USER0);
2002                         memset(userpage + zero_offset, 0, iosize);
2003                         flush_dcache_page(page);
2004                         kunmap_atomic(userpage, KM_USER0);
2005                 }
2006         }
2007         while (cur <= end) {
2008                 if (cur >= last_byte) {
2009                         char *userpage;
2010                         iosize = PAGE_CACHE_SIZE - page_offset;
2011                         userpage = kmap_atomic(page, KM_USER0);
2012                         memset(userpage + page_offset, 0, iosize);
2013                         flush_dcache_page(page);
2014                         kunmap_atomic(userpage, KM_USER0);
2015                         set_extent_uptodate(tree, cur, cur + iosize - 1,
2016                                             GFP_NOFS);
2017                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2018                         break;
2019                 }
2020                 em = get_extent(inode, page, page_offset, cur,
2021                                 end - cur + 1, 0);
2022                 if (IS_ERR(em) || !em) {
2023                         SetPageError(page);
2024                         unlock_extent(tree, cur, end, GFP_NOFS);
2025                         break;
2026                 }
2027                 extent_offset = cur - em->start;
2028                 if (extent_map_end(em) <= cur) {
2029 printk("bad mapping em [%Lu %Lu] cur %Lu\n", em->start, extent_map_end(em), cur);
2030                 }
2031                 BUG_ON(extent_map_end(em) <= cur);
2032                 if (end < cur) {
2033 printk("2bad mapping end %Lu cur %Lu\n", end, cur);
2034                 }
2035                 BUG_ON(end < cur);
2036
2037                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2038                         this_bio_flag = EXTENT_BIO_COMPRESSED;
2039
2040                 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2041                 cur_end = min(extent_map_end(em) - 1, end);
2042                 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2043                 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2044                         disk_io_size = em->block_len;
2045                         sector = em->block_start >> 9;
2046                 } else {
2047                         sector = (em->block_start + extent_offset) >> 9;
2048                         disk_io_size = iosize;
2049                 }
2050                 bdev = em->bdev;
2051                 block_start = em->block_start;
2052                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2053                         block_start = EXTENT_MAP_HOLE;
2054                 free_extent_map(em);
2055                 em = NULL;
2056
2057                 /* we've found a hole, just zero and go on */
2058                 if (block_start == EXTENT_MAP_HOLE) {
2059                         char *userpage;
2060                         userpage = kmap_atomic(page, KM_USER0);
2061                         memset(userpage + page_offset, 0, iosize);
2062                         flush_dcache_page(page);
2063                         kunmap_atomic(userpage, KM_USER0);
2064
2065                         set_extent_uptodate(tree, cur, cur + iosize - 1,
2066                                             GFP_NOFS);
2067                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2068                         cur = cur + iosize;
2069                         page_offset += iosize;
2070                         continue;
2071                 }
2072                 /* the get_extent function already copied into the page */
2073                 if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
2074                         check_page_uptodate(tree, page);
2075                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2076                         cur = cur + iosize;
2077                         page_offset += iosize;
2078                         continue;
2079                 }
2080                 /* we have an inline extent but it didn't get marked up
2081                  * to date.  Error out
2082                  */
2083                 if (block_start == EXTENT_MAP_INLINE) {
2084                         SetPageError(page);
2085                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2086                         cur = cur + iosize;
2087                         page_offset += iosize;
2088                         continue;
2089                 }
2090
2091                 ret = 0;
2092                 if (tree->ops && tree->ops->readpage_io_hook) {
2093                         ret = tree->ops->readpage_io_hook(page, cur,
2094                                                           cur + iosize - 1);
2095                 }
2096                 if (!ret) {
2097                         unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2098                         pnr -= page->index;
2099                         ret = submit_extent_page(READ, tree, page,
2100                                          sector, disk_io_size, page_offset,
2101                                          bdev, bio, pnr,
2102                                          end_bio_extent_readpage, mirror_num,
2103                                          *bio_flags,
2104                                          this_bio_flag);
2105                         nr++;
2106                         *bio_flags = this_bio_flag;
2107                 }
2108                 if (ret)
2109                         SetPageError(page);
2110                 cur = cur + iosize;
2111                 page_offset += iosize;
2112         }
2113         if (!nr) {
2114                 if (!PageError(page))
2115                         SetPageUptodate(page);
2116                 unlock_page(page);
2117         }
2118         return 0;
2119 }
2120
2121 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2122                             get_extent_t *get_extent)
2123 {
2124         struct bio *bio = NULL;
2125         unsigned long bio_flags = 0;
2126         int ret;
2127
2128         ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2129                                       &bio_flags);
2130         if (bio)
2131                 submit_one_bio(READ, bio, 0, bio_flags);
2132         return ret;
2133 }
2134 EXPORT_SYMBOL(extent_read_full_page);
2135
2136 /*
2137  * the writepage semantics are similar to regular writepage.  extent
2138  * records are inserted to lock ranges in the tree, and as dirty areas
2139  * are found, they are marked writeback.  Then the lock bits are removed
2140  * and the end_io handler clears the writeback ranges
2141  */
2142 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2143                               void *data)
2144 {
2145         struct inode *inode = page->mapping->host;
2146         struct extent_page_data *epd = data;
2147         struct extent_io_tree *tree = epd->tree;
2148         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2149         u64 delalloc_start;
2150         u64 page_end = start + PAGE_CACHE_SIZE - 1;
2151         u64 end;
2152         u64 cur = start;
2153         u64 extent_offset;
2154         u64 last_byte = i_size_read(inode);
2155         u64 block_start;
2156         u64 iosize;
2157         u64 unlock_start;
2158         sector_t sector;
2159         struct extent_map *em;
2160         struct block_device *bdev;
2161         int ret;
2162         int nr = 0;
2163         size_t pg_offset = 0;
2164         size_t blocksize;
2165         loff_t i_size = i_size_read(inode);
2166         unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2167         u64 nr_delalloc;
2168         u64 delalloc_end;
2169         int page_started;
2170         int compressed;
2171         unsigned long nr_written = 0;
2172
2173         WARN_ON(!PageLocked(page));
2174         pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2175         if (page->index > end_index ||
2176            (page->index == end_index && !pg_offset)) {
2177                 page->mapping->a_ops->invalidatepage(page, 0);
2178                 unlock_page(page);
2179                 return 0;
2180         }
2181
2182         if (page->index == end_index) {
2183                 char *userpage;
2184
2185                 userpage = kmap_atomic(page, KM_USER0);
2186                 memset(userpage + pg_offset, 0,
2187                        PAGE_CACHE_SIZE - pg_offset);
2188                 kunmap_atomic(userpage, KM_USER0);
2189                 flush_dcache_page(page);
2190         }
2191         pg_offset = 0;
2192
2193         set_page_extent_mapped(page);
2194
2195         delalloc_start = start;
2196         delalloc_end = 0;
2197         page_started = 0;
2198         if (!epd->extent_locked) {
2199                 while(delalloc_end < page_end) {
2200                         nr_delalloc = find_lock_delalloc_range(inode, tree,
2201                                                        page,
2202                                                        &delalloc_start,
2203                                                        &delalloc_end,
2204                                                        128 * 1024 * 1024);
2205                         if (nr_delalloc == 0) {
2206                                 delalloc_start = delalloc_end + 1;
2207                                 continue;
2208                         }
2209                         tree->ops->fill_delalloc(inode, page, delalloc_start,
2210                                                  delalloc_end, &page_started,
2211                                                  &nr_written);
2212                         delalloc_start = delalloc_end + 1;
2213                 }
2214
2215                 /* did the fill delalloc function already unlock and start
2216                  * the IO?
2217                  */
2218                 if (page_started) {
2219                         ret = 0;
2220                         goto update_nr_written;
2221                 }
2222         }
2223         lock_extent(tree, start, page_end, GFP_NOFS);
2224
2225         unlock_start = start;
2226
2227         if (tree->ops && tree->ops->writepage_start_hook) {
2228                 ret = tree->ops->writepage_start_hook(page, start,
2229                                                       page_end);
2230                 if (ret == -EAGAIN) {
2231                         unlock_extent(tree, start, page_end, GFP_NOFS);
2232                         redirty_page_for_writepage(wbc, page);
2233                         unlock_page(page);
2234                         ret = 0;
2235                         goto update_nr_written;
2236                 }
2237         }
2238
2239         nr_written++;
2240
2241         end = page_end;
2242         if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
2243                 printk("found delalloc bits after lock_extent\n");
2244         }
2245
2246         if (last_byte <= start) {
2247                 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
2248                 unlock_extent(tree, start, page_end, GFP_NOFS);
2249                 if (tree->ops && tree->ops->writepage_end_io_hook)
2250                         tree->ops->writepage_end_io_hook(page, start,
2251                                                          page_end, NULL, 1);
2252                 unlock_start = page_end + 1;
2253                 goto done;
2254         }
2255
2256         set_extent_uptodate(tree, start, page_end, GFP_NOFS);
2257         blocksize = inode->i_sb->s_blocksize;
2258
2259         while (cur <= end) {
2260                 if (cur >= last_byte) {
2261                         clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
2262                         unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2263                         if (tree->ops && tree->ops->writepage_end_io_hook)
2264                                 tree->ops->writepage_end_io_hook(page, cur,
2265                                                          page_end, NULL, 1);
2266                         unlock_start = page_end + 1;
2267                         break;
2268                 }
2269                 em = epd->get_extent(inode, page, pg_offset, cur,
2270                                      end - cur + 1, 1);
2271                 if (IS_ERR(em) || !em) {
2272                         SetPageError(page);
2273                         break;
2274                 }
2275
2276                 extent_offset = cur - em->start;
2277                 BUG_ON(extent_map_end(em) <= cur);
2278                 BUG_ON(end < cur);
2279                 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2280                 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2281                 sector = (em->block_start + extent_offset) >> 9;
2282                 bdev = em->bdev;
2283                 block_start = em->block_start;
2284                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2285                 free_extent_map(em);
2286                 em = NULL;
2287
2288                 /*
2289                  * compressed and inline extents are written through other
2290                  * paths in the FS
2291                  */
2292                 if (compressed || block_start == EXTENT_MAP_HOLE ||
2293                     block_start == EXTENT_MAP_INLINE) {
2294                         clear_extent_dirty(tree, cur,
2295                                            cur + iosize - 1, GFP_NOFS);
2296
2297                         unlock_extent(tree, unlock_start, cur + iosize -1,
2298                                       GFP_NOFS);
2299
2300                         /*
2301                          * end_io notification does not happen here for
2302                          * compressed extents
2303                          */
2304                         if (!compressed && tree->ops &&
2305                             tree->ops->writepage_end_io_hook)
2306                                 tree->ops->writepage_end_io_hook(page, cur,
2307                                                          cur + iosize - 1,
2308                                                          NULL, 1);
2309                         else if (compressed) {
2310                                 /* we don't want to end_page_writeback on
2311                                  * a compressed extent.  this happens
2312                                  * elsewhere
2313                                  */
2314                                 nr++;
2315                         }
2316
2317                         cur += iosize;
2318                         pg_offset += iosize;
2319                         unlock_start = cur;
2320                         continue;
2321                 }
2322                 /* leave this out until we have a page_mkwrite call */
2323                 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2324                                    EXTENT_DIRTY, 0)) {
2325                         cur = cur + iosize;
2326                         pg_offset += iosize;
2327                         continue;
2328                 }
2329
2330                 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
2331                 if (tree->ops && tree->ops->writepage_io_hook) {
2332                         ret = tree->ops->writepage_io_hook(page, cur,
2333                                                 cur + iosize - 1);
2334                 } else {
2335                         ret = 0;
2336                 }
2337                 if (ret) {
2338                         SetPageError(page);
2339                 } else {
2340                         unsigned long max_nr = end_index + 1;
2341
2342                         set_range_writeback(tree, cur, cur + iosize - 1);
2343                         if (!PageWriteback(page)) {
2344                                 printk("warning page %lu not writeback, "
2345                                        "cur %llu end %llu\n", page->index,
2346                                        (unsigned long long)cur,
2347                                        (unsigned long long)end);
2348                         }
2349
2350                         ret = submit_extent_page(WRITE, tree, page, sector,
2351                                                  iosize, pg_offset, bdev,
2352                                                  &epd->bio, max_nr,
2353                                                  end_bio_extent_writepage,
2354                                                  0, 0, 0);
2355                         if (ret)
2356                                 SetPageError(page);
2357                 }
2358                 cur = cur + iosize;
2359                 pg_offset += iosize;
2360                 nr++;
2361         }
2362 done:
2363         if (nr == 0) {
2364                 /* make sure the mapping tag for page dirty gets cleared */
2365                 set_page_writeback(page);
2366                 end_page_writeback(page);
2367         }
2368         if (unlock_start <= page_end)
2369                 unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2370         unlock_page(page);
2371
2372 update_nr_written:
2373         wbc->nr_to_write -= nr_written;
2374         if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2375             wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2376                 page->mapping->writeback_index = page->index + nr_written;
2377         return 0;
2378 }
2379
2380 /**
2381  * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2382  * @mapping: address space structure to write
2383  * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2384  * @writepage: function called for each page
2385  * @data: data passed to writepage function
2386  *
2387  * If a page is already under I/O, write_cache_pages() skips it, even
2388  * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
2389  * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
2390  * and msync() need to guarantee that all the data which was dirty at the time
2391  * the call was made get new I/O started against them.  If wbc->sync_mode is
2392  * WB_SYNC_ALL then we were called for data integrity and we must wait for
2393  * existing IO to complete.
2394  */
2395 int extent_write_cache_pages(struct extent_io_tree *tree,
2396                              struct address_space *mapping,
2397                              struct writeback_control *wbc,
2398                              writepage_t writepage, void *data)
2399 {
2400         struct backing_dev_info *bdi = mapping->backing_dev_info;
2401         int ret = 0;
2402         int done = 0;
2403         struct pagevec pvec;
2404         int nr_pages;
2405         pgoff_t index;
2406         pgoff_t end;            /* Inclusive */
2407         int scanned = 0;
2408         int range_whole = 0;
2409
2410         if (wbc->nonblocking && bdi_write_congested(bdi)) {
2411                 wbc->encountered_congestion = 1;
2412                 return 0;
2413         }
2414
2415         pagevec_init(&pvec, 0);
2416         if (wbc->range_cyclic) {
2417                 index = mapping->writeback_index; /* Start from prev offset */
2418                 end = -1;
2419         } else {
2420                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2421                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2422                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2423                         range_whole = 1;
2424                 scanned = 1;
2425         }
2426 retry:
2427         while (!done && (index <= end) &&
2428                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
2429                                               PAGECACHE_TAG_DIRTY,
2430                                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2431                 unsigned i;
2432
2433                 scanned = 1;
2434                 for (i = 0; i < nr_pages; i++) {
2435                         struct page *page = pvec.pages[i];
2436
2437                         /*
2438                          * At this point we hold neither mapping->tree_lock nor
2439                          * lock on the page itself: the page may be truncated or
2440                          * invalidated (changing page->mapping to NULL), or even
2441                          * swizzled back from swapper_space to tmpfs file
2442                          * mapping
2443                          */
2444                         if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2445                                 tree->ops->write_cache_pages_lock_hook(page);
2446                         else
2447                                 lock_page(page);
2448
2449                         if (unlikely(page->mapping != mapping)) {
2450                                 unlock_page(page);
2451                                 continue;
2452                         }
2453
2454                         if (!wbc->range_cyclic && page->index > end) {
2455                                 done = 1;
2456                                 unlock_page(page);
2457                                 continue;
2458                         }
2459
2460                         if (wbc->sync_mode != WB_SYNC_NONE)
2461                                 wait_on_page_writeback(page);
2462
2463                         if (PageWriteback(page) ||
2464                             !clear_page_dirty_for_io(page)) {
2465                                 unlock_page(page);
2466                                 continue;
2467                         }
2468
2469                         ret = (*writepage)(page, wbc, data);
2470
2471                         if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2472                                 unlock_page(page);
2473                                 ret = 0;
2474                         }
2475                         if (ret || wbc->nr_to_write <= 0)
2476                                 done = 1;
2477                         if (wbc->nonblocking && bdi_write_congested(bdi)) {
2478                                 wbc->encountered_congestion = 1;
2479                                 done = 1;
2480                         }
2481                 }
2482                 pagevec_release(&pvec);
2483                 cond_resched();
2484         }
2485         if (!scanned && !done) {
2486                 /*
2487                  * We hit the last page and there is more work to be done: wrap
2488                  * back to the start of the file
2489                  */
2490                 scanned = 1;
2491                 index = 0;
2492                 goto retry;
2493         }
2494         return ret;
2495 }
2496 EXPORT_SYMBOL(extent_write_cache_pages);
2497
2498 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2499                           get_extent_t *get_extent,
2500                           struct writeback_control *wbc)
2501 {
2502         int ret;
2503         struct address_space *mapping = page->mapping;
2504         struct extent_page_data epd = {
2505                 .bio = NULL,
2506                 .tree = tree,
2507                 .get_extent = get_extent,
2508                 .extent_locked = 0,
2509         };
2510         struct writeback_control wbc_writepages = {
2511                 .bdi            = wbc->bdi,
2512                 .sync_mode      = WB_SYNC_NONE,
2513                 .older_than_this = NULL,
2514                 .nr_to_write    = 64,
2515                 .range_start    = page_offset(page) + PAGE_CACHE_SIZE,
2516                 .range_end      = (loff_t)-1,
2517         };
2518
2519
2520         ret = __extent_writepage(page, wbc, &epd);
2521
2522         extent_write_cache_pages(tree, mapping, &wbc_writepages,
2523                                  __extent_writepage, &epd);
2524         if (epd.bio) {
2525                 submit_one_bio(WRITE, epd.bio, 0, 0);
2526         }
2527         return ret;
2528 }
2529 EXPORT_SYMBOL(extent_write_full_page);
2530
2531 int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2532                               u64 start, u64 end, get_extent_t *get_extent,
2533                               int mode)
2534 {
2535         int ret = 0;
2536         struct address_space *mapping = inode->i_mapping;
2537         struct page *page;
2538         unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2539                 PAGE_CACHE_SHIFT;
2540
2541         struct extent_page_data epd = {
2542                 .bio = NULL,
2543                 .tree = tree,
2544                 .get_extent = get_extent,
2545                 .extent_locked = 1,
2546         };
2547         struct writeback_control wbc_writepages = {
2548                 .bdi            = inode->i_mapping->backing_dev_info,
2549                 .sync_mode      = mode,
2550                 .older_than_this = NULL,
2551                 .nr_to_write    = nr_pages * 2,
2552                 .range_start    = start,
2553                 .range_end      = end + 1,
2554         };
2555
2556         while(start <= end) {
2557                 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2558                 if (clear_page_dirty_for_io(page))
2559                         ret = __extent_writepage(page, &wbc_writepages, &epd);
2560                 else {
2561                         if (tree->ops && tree->ops->writepage_end_io_hook)
2562                                 tree->ops->writepage_end_io_hook(page, start,
2563                                                  start + PAGE_CACHE_SIZE - 1,
2564                                                  NULL, 1);
2565                         unlock_page(page);
2566                 }
2567                 page_cache_release(page);
2568                 start += PAGE_CACHE_SIZE;
2569         }
2570
2571         if (epd.bio)
2572                 submit_one_bio(WRITE, epd.bio, 0, 0);
2573         return ret;
2574 }
2575 EXPORT_SYMBOL(extent_write_locked_range);
2576
2577
2578 int extent_writepages(struct extent_io_tree *tree,
2579                       struct address_space *mapping,
2580                       get_extent_t *get_extent,
2581                       struct writeback_control *wbc)
2582 {
2583         int ret = 0;
2584         struct extent_page_data epd = {
2585                 .bio = NULL,
2586                 .tree = tree,
2587                 .get_extent = get_extent,
2588                 .extent_locked = 0,
2589         };
2590
2591         ret = extent_write_cache_pages(tree, mapping, wbc,
2592                                        __extent_writepage, &epd);
2593         if (epd.bio) {
2594                 submit_one_bio(WRITE, epd.bio, 0, 0);
2595         }
2596         return ret;
2597 }
2598 EXPORT_SYMBOL(extent_writepages);
2599
2600 int extent_readpages(struct extent_io_tree *tree,
2601                      struct address_space *mapping,
2602                      struct list_head *pages, unsigned nr_pages,
2603                      get_extent_t get_extent)
2604 {
2605         struct bio *bio = NULL;
2606         unsigned page_idx;
2607         struct pagevec pvec;
2608         unsigned long bio_flags = 0;
2609
2610         pagevec_init(&pvec, 0);
2611         for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2612                 struct page *page = list_entry(pages->prev, struct page, lru);
2613
2614                 prefetchw(&page->flags);
2615                 list_del(&page->lru);
2616                 /*
2617                  * what we want to do here is call add_to_page_cache_lru,
2618                  * but that isn't exported, so we reproduce it here
2619                  */
2620                 if (!add_to_page_cache(page, mapping,
2621                                         page->index, GFP_KERNEL)) {
2622
2623                         /* open coding of lru_cache_add, also not exported */
2624                         page_cache_get(page);
2625                         if (!pagevec_add(&pvec, page))
2626                                 __pagevec_lru_add(&pvec);
2627                         __extent_read_full_page(tree, page, get_extent,
2628                                                 &bio, 0, &bio_flags);
2629                 }
2630                 page_cache_release(page);
2631         }
2632         if (pagevec_count(&pvec))
2633                 __pagevec_lru_add(&pvec);
2634         BUG_ON(!list_empty(pages));
2635         if (bio)
2636                 submit_one_bio(READ, bio, 0, bio_flags);
2637         return 0;
2638 }
2639 EXPORT_SYMBOL(extent_readpages);
2640
2641 /*
2642  * basic invalidatepage code, this waits on any locked or writeback
2643  * ranges corresponding to the page, and then deletes any extent state
2644  * records from the tree
2645  */
2646 int extent_invalidatepage(struct extent_io_tree *tree,
2647                           struct page *page, unsigned long offset)
2648 {
2649         u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2650         u64 end = start + PAGE_CACHE_SIZE - 1;
2651         size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2652
2653         start += (offset + blocksize -1) & ~(blocksize - 1);
2654         if (start > end)
2655                 return 0;
2656
2657         lock_extent(tree, start, end, GFP_NOFS);
2658         wait_on_extent_writeback(tree, start, end);
2659         clear_extent_bit(tree, start, end,
2660                          EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
2661                          1, 1, GFP_NOFS);
2662         return 0;
2663 }
2664 EXPORT_SYMBOL(extent_invalidatepage);
2665
2666 /*
2667  * simple commit_write call, set_range_dirty is used to mark both
2668  * the pages and the extent records as dirty
2669  */
2670 int extent_commit_write(struct extent_io_tree *tree,
2671                         struct inode *inode, struct page *page,
2672                         unsigned from, unsigned to)
2673 {
2674         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
2675
2676         set_page_extent_mapped(page);
2677         set_page_dirty(page);
2678
2679         if (pos > inode->i_size) {
2680                 i_size_write(inode, pos);
2681                 mark_inode_dirty(inode);
2682         }
2683         return 0;
2684 }
2685 EXPORT_SYMBOL(extent_commit_write);
2686
2687 int extent_prepare_write(struct extent_io_tree *tree,
2688                          struct inode *inode, struct page *page,
2689                          unsigned from, unsigned to, get_extent_t *get_extent)
2690 {
2691         u64 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2692         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
2693         u64 block_start;
2694         u64 orig_block_start;
2695         u64 block_end;
2696         u64 cur_end;
2697         struct extent_map *em;
2698         unsigned blocksize = 1 << inode->i_blkbits;
2699         size_t page_offset = 0;
2700         size_t block_off_start;
2701         size_t block_off_end;
2702         int err = 0;
2703         int iocount = 0;
2704         int ret = 0;
2705         int isnew;
2706
2707         set_page_extent_mapped(page);
2708
2709         block_start = (page_start + from) & ~((u64)blocksize - 1);
2710         block_end = (page_start + to - 1) | (blocksize - 1);
2711         orig_block_start = block_start;
2712
2713         lock_extent(tree, page_start, page_end, GFP_NOFS);
2714         while(block_start <= block_end) {
2715                 em = get_extent(inode, page, page_offset, block_start,
2716                                 block_end - block_start + 1, 1);
2717                 if (IS_ERR(em) || !em) {
2718                         goto err;
2719                 }
2720                 cur_end = min(block_end, extent_map_end(em) - 1);
2721                 block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
2722                 block_off_end = block_off_start + blocksize;
2723                 isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
2724
2725                 if (!PageUptodate(page) && isnew &&
2726                     (block_off_end > to || block_off_start < from)) {
2727                         void *kaddr;
2728
2729                         kaddr = kmap_atomic(page, KM_USER0);
2730                         if (block_off_end > to)
2731                                 memset(kaddr + to, 0, block_off_end - to);
2732                         if (block_off_start < from)
2733                                 memset(kaddr + block_off_start, 0,
2734                                        from - block_off_start);
2735                         flush_dcache_page(page);
2736                         kunmap_atomic(kaddr, KM_USER0);
2737                 }
2738                 if ((em->block_start != EXTENT_MAP_HOLE &&
2739                      em->block_start != EXTENT_MAP_INLINE) &&
2740                     !isnew && !PageUptodate(page) &&
2741                     (block_off_end > to || block_off_start < from) &&
2742                     !test_range_bit(tree, block_start, cur_end,
2743                                     EXTENT_UPTODATE, 1)) {
2744                         u64 sector;
2745                         u64 extent_offset = block_start - em->start;
2746                         size_t iosize;
2747                         sector = (em->block_start + extent_offset) >> 9;
2748                         iosize = (cur_end - block_start + blocksize) &
2749                                 ~((u64)blocksize - 1);
2750                         /*
2751                          * we've already got the extent locked, but we
2752                          * need to split the state such that our end_bio
2753                          * handler can clear the lock.
2754                          */
2755                         set_extent_bit(tree, block_start,
2756                                        block_start + iosize - 1,
2757                                        EXTENT_LOCKED, 0, NULL, GFP_NOFS);
2758                         ret = submit_extent_page(READ, tree, page,
2759                                          sector, iosize, page_offset, em->bdev,
2760                                          NULL, 1,
2761                                          end_bio_extent_preparewrite, 0,
2762                                          0, 0);
2763                         iocount++;
2764                         block_start = block_start + iosize;
2765                 } else {
2766                         set_extent_uptodate(tree, block_start, cur_end,
2767                                             GFP_NOFS);
2768                         unlock_extent(tree, block_start, cur_end, GFP_NOFS);
2769                         block_start = cur_end + 1;
2770                 }
2771                 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
2772                 free_extent_map(em);
2773         }
2774         if (iocount) {
2775                 wait_extent_bit(tree, orig_block_start,
2776                                 block_end, EXTENT_LOCKED);
2777         }
2778         check_page_uptodate(tree, page);
2779 err:
2780         /* FIXME, zero out newly allocated blocks on error */
2781         return err;
2782 }
2783 EXPORT_SYMBOL(extent_prepare_write);
2784
2785 /*
2786  * a helper for releasepage, this tests for areas of the page that
2787  * are locked or under IO and drops the related state bits if it is safe
2788  * to drop the page.
2789  */
2790 int try_release_extent_state(struct extent_map_tree *map,
2791                              struct extent_io_tree *tree, struct page *page,
2792                              gfp_t mask)
2793 {
2794         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2795         u64 end = start + PAGE_CACHE_SIZE - 1;
2796         int ret = 1;
2797
2798         if (test_range_bit(tree, start, end,
2799                            EXTENT_IOBITS | EXTENT_ORDERED, 0))
2800                 ret = 0;
2801         else {
2802                 if ((mask & GFP_NOFS) == GFP_NOFS)
2803                         mask = GFP_NOFS;
2804                 clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
2805                                  1, 1, mask);
2806         }
2807         return ret;
2808 }
2809 EXPORT_SYMBOL(try_release_extent_state);
2810
2811 /*
2812  * a helper for releasepage.  As long as there are no locked extents
2813  * in the range corresponding to the page, both state records and extent
2814  * map records are removed
2815  */
2816 int try_release_extent_mapping(struct extent_map_tree *map,
2817                                struct extent_io_tree *tree, struct page *page,
2818                                gfp_t mask)
2819 {
2820         struct extent_map *em;
2821         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2822         u64 end = start + PAGE_CACHE_SIZE - 1;
2823
2824         if ((mask & __GFP_WAIT) &&
2825             page->mapping->host->i_size > 16 * 1024 * 1024) {
2826                 u64 len;
2827                 while (start <= end) {
2828                         len = end - start + 1;
2829                         spin_lock(&map->lock);
2830                         em = lookup_extent_mapping(map, start, len);
2831                         if (!em || IS_ERR(em)) {
2832                                 spin_unlock(&map->lock);
2833                                 break;
2834                         }
2835                         if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2836                             em->start != start) {
2837                                 spin_unlock(&map->lock);
2838                                 free_extent_map(em);
2839                                 break;
2840                         }
2841                         if (!test_range_bit(tree, em->start,
2842                                             extent_map_end(em) - 1,
2843                                             EXTENT_LOCKED | EXTENT_WRITEBACK |
2844                                             EXTENT_ORDERED,
2845                                             0)) {
2846                                 remove_extent_mapping(map, em);
2847                                 /* once for the rb tree */
2848                                 free_extent_map(em);
2849                         }
2850                         start = extent_map_end(em);
2851                         spin_unlock(&map->lock);
2852
2853                         /* once for us */
2854                         free_extent_map(em);
2855                 }
2856         }
2857         return try_release_extent_state(map, tree, page, mask);
2858 }
2859 EXPORT_SYMBOL(try_release_extent_mapping);
2860
2861 sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
2862                 get_extent_t *get_extent)
2863 {
2864         struct inode *inode = mapping->host;
2865         u64 start = iblock << inode->i_blkbits;
2866         sector_t sector = 0;
2867         size_t blksize = (1 << inode->i_blkbits);
2868         struct extent_map *em;
2869
2870         lock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
2871                     GFP_NOFS);
2872         em = get_extent(inode, NULL, 0, start, blksize, 0);
2873         unlock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
2874                       GFP_NOFS);
2875         if (!em || IS_ERR(em))
2876                 return 0;
2877
2878         if (em->block_start > EXTENT_MAP_LAST_BYTE)
2879                 goto out;
2880
2881         sector = (em->block_start + start - em->start) >> inode->i_blkbits;
2882 out:
2883         free_extent_map(em);
2884         return sector;
2885 }
2886
2887 static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2888                                               unsigned long i)
2889 {
2890         struct page *p;
2891         struct address_space *mapping;
2892
2893         if (i == 0)
2894                 return eb->first_page;
2895         i += eb->start >> PAGE_CACHE_SHIFT;
2896         mapping = eb->first_page->mapping;
2897         if (!mapping)
2898                 return NULL;
2899
2900         /*
2901          * extent_buffer_page is only called after pinning the page
2902          * by increasing the reference count.  So we know the page must
2903          * be in the radix tree.
2904          */
2905         rcu_read_lock();
2906         p = radix_tree_lookup(&mapping->page_tree, i);
2907         rcu_read_unlock();
2908
2909         return p;
2910 }
2911
2912 static inline unsigned long num_extent_pages(u64 start, u64 len)
2913 {
2914         return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2915                 (start >> PAGE_CACHE_SHIFT);
2916 }
2917
2918 static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2919                                                    u64 start,
2920                                                    unsigned long len,
2921                                                    gfp_t mask)
2922 {
2923         struct extent_buffer *eb = NULL;
2924 #ifdef LEAK_DEBUG
2925         unsigned long flags;
2926 #endif
2927
2928         eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2929         eb->start = start;
2930         eb->len = len;
2931         mutex_init(&eb->mutex);
2932 #ifdef LEAK_DEBUG
2933         spin_lock_irqsave(&leak_lock, flags);
2934         list_add(&eb->leak_list, &buffers);
2935         spin_unlock_irqrestore(&leak_lock, flags);
2936 #endif
2937         atomic_set(&eb->refs, 1);
2938
2939         return eb;
2940 }
2941
2942 static void __free_extent_buffer(struct extent_buffer *eb)
2943 {
2944 #ifdef LEAK_DEBUG
2945         unsigned long flags;
2946         spin_lock_irqsave(&leak_lock, flags);
2947         list_del(&eb->leak_list);
2948         spin_unlock_irqrestore(&leak_lock, flags);
2949 #endif
2950         kmem_cache_free(extent_buffer_cache, eb);
2951 }
2952
2953 struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
2954                                           u64 start, unsigned long len,
2955                                           struct page *page0,
2956                                           gfp_t mask)
2957 {
2958         unsigned long num_pages = num_extent_pages(start, len);
2959         unsigned long i;
2960         unsigned long index = start >> PAGE_CACHE_SHIFT;
2961         struct extent_buffer *eb;
2962         struct extent_buffer *exists = NULL;
2963         struct page *p;
2964         struct address_space *mapping = tree->mapping;
2965         int uptodate = 1;
2966
2967         spin_lock(&tree->buffer_lock);
2968         eb = buffer_search(tree, start);
2969         if (eb) {
2970                 atomic_inc(&eb->refs);
2971                 spin_unlock(&tree->buffer_lock);
2972                 mark_page_accessed(eb->first_page);
2973                 return eb;
2974         }
2975         spin_unlock(&tree->buffer_lock);
2976
2977         eb = __alloc_extent_buffer(tree, start, len, mask);
2978         if (!eb)
2979                 return NULL;
2980
2981         if (page0) {
2982                 eb->first_page = page0;
2983                 i = 1;
2984                 index++;
2985                 page_cache_get(page0);
2986                 mark_page_accessed(page0);
2987                 set_page_extent_mapped(page0);
2988                 set_page_extent_head(page0, len);
2989                 uptodate = PageUptodate(page0);
2990         } else {
2991                 i = 0;
2992         }
2993         for (; i < num_pages; i++, index++) {
2994                 p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
2995                 if (!p) {
2996                         WARN_ON(1);
2997                         goto free_eb;
2998                 }
2999                 set_page_extent_mapped(p);
3000                 mark_page_accessed(p);
3001                 if (i == 0) {
3002                         eb->first_page = p;
3003                         set_page_extent_head(p, len);
3004                 } else {
3005                         set_page_private(p, EXTENT_PAGE_PRIVATE);
3006                 }
3007                 if (!PageUptodate(p))
3008                         uptodate = 0;
3009                 unlock_page(p);
3010         }
3011         if (uptodate)
3012                 eb->flags |= EXTENT_UPTODATE;
3013         eb->flags |= EXTENT_BUFFER_FILLED;
3014
3015         spin_lock(&tree->buffer_lock);
3016         exists = buffer_tree_insert(tree, start, &eb->rb_node);
3017         if (exists) {
3018                 /* add one reference for the caller */
3019                 atomic_inc(&exists->refs);
3020                 spin_unlock(&tree->buffer_lock);
3021                 goto free_eb;
3022         }
3023         spin_unlock(&tree->buffer_lock);
3024
3025         /* add one reference for the tree */
3026         atomic_inc(&eb->refs);
3027         return eb;
3028
3029 free_eb:
3030         if (!atomic_dec_and_test(&eb->refs))
3031                 return exists;
3032         for (index = 1; index < i; index++)
3033                 page_cache_release(extent_buffer_page(eb, index));
3034         page_cache_release(extent_buffer_page(eb, 0));
3035         __free_extent_buffer(eb);
3036         return exists;
3037 }
3038 EXPORT_SYMBOL(alloc_extent_buffer);
3039
3040 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3041                                          u64 start, unsigned long len,
3042                                           gfp_t mask)
3043 {
3044         struct extent_buffer *eb;
3045
3046         spin_lock(&tree->buffer_lock);
3047         eb = buffer_search(tree, start);
3048         if (eb)
3049                 atomic_inc(&eb->refs);
3050         spin_unlock(&tree->buffer_lock);
3051
3052         if (eb)
3053                 mark_page_accessed(eb->first_page);
3054
3055         return eb;
3056 }
3057 EXPORT_SYMBOL(find_extent_buffer);
3058
3059 void free_extent_buffer(struct extent_buffer *eb)
3060 {
3061         if (!eb)
3062                 return;
3063
3064         if (!atomic_dec_and_test(&eb->refs))
3065                 return;
3066
3067         WARN_ON(1);
3068 }
3069 EXPORT_SYMBOL(free_extent_buffer);
3070
3071 int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3072                               struct extent_buffer *eb)
3073 {
3074         int set;
3075         unsigned long i;
3076         unsigned long num_pages;
3077         struct page *page;
3078
3079         u64 start = eb->start;
3080         u64 end = start + eb->len - 1;
3081
3082         set = clear_extent_dirty(tree, start, end, GFP_NOFS);
3083         num_pages = num_extent_pages(eb->start, eb->len);
3084
3085         for (i = 0; i < num_pages; i++) {
3086                 page = extent_buffer_page(eb, i);
3087                 lock_page(page);
3088                 if (i == 0)
3089                         set_page_extent_head(page, eb->len);
3090                 else
3091                         set_page_private(page, EXTENT_PAGE_PRIVATE);
3092
3093                 /*
3094                  * if we're on the last page or the first page and the
3095                  * block isn't aligned on a page boundary, do extra checks
3096                  * to make sure we don't clean page that is partially dirty
3097                  */
3098                 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3099                     ((i == num_pages - 1) &&
3100                      ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3101                         start = (u64)page->index << PAGE_CACHE_SHIFT;
3102                         end  = start + PAGE_CACHE_SIZE - 1;
3103                         if (test_range_bit(tree, start, end,
3104                                            EXTENT_DIRTY, 0)) {
3105                                 unlock_page(page);
3106                                 continue;
3107                         }
3108                 }
3109                 clear_page_dirty_for_io(page);
3110                 spin_lock_irq(&page->mapping->tree_lock);
3111                 if (!PageDirty(page)) {
3112                         radix_tree_tag_clear(&page->mapping->page_tree,
3113                                                 page_index(page),
3114                                                 PAGECACHE_TAG_DIRTY);
3115                 }
3116                 spin_unlock_irq(&page->mapping->tree_lock);
3117                 unlock_page(page);
3118         }
3119         return 0;
3120 }
3121 EXPORT_SYMBOL(clear_extent_buffer_dirty);
3122
3123 int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
3124                                     struct extent_buffer *eb)
3125 {
3126         return wait_on_extent_writeback(tree, eb->start,
3127                                         eb->start + eb->len - 1);
3128 }
3129 EXPORT_SYMBOL(wait_on_extent_buffer_writeback);
3130
3131 int set_extent_buffer_dirty(struct extent_io_tree *tree,
3132                              struct extent_buffer *eb)
3133 {
3134         unsigned long i;
3135         unsigned long num_pages;
3136
3137         num_pages = num_extent_pages(eb->start, eb->len);
3138         for (i = 0; i < num_pages; i++) {
3139                 struct page *page = extent_buffer_page(eb, i);
3140                 /* writepage may need to do something special for the
3141                  * first page, we have to make sure page->private is
3142                  * properly set.  releasepage may drop page->private
3143                  * on us if the page isn't already dirty.
3144                  */
3145                 lock_page(page);
3146                 if (i == 0) {
3147                         set_page_extent_head(page, eb->len);
3148                 } else if (PagePrivate(page) &&
3149                            page->private != EXTENT_PAGE_PRIVATE) {
3150                         set_page_extent_mapped(page);
3151                 }
3152                 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3153                 set_extent_dirty(tree, page_offset(page),
3154                                  page_offset(page) + PAGE_CACHE_SIZE -1,
3155                                  GFP_NOFS);
3156                 unlock_page(page);
3157         }
3158         return 0;
3159 }
3160 EXPORT_SYMBOL(set_extent_buffer_dirty);
3161
3162 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3163                                 struct extent_buffer *eb)
3164 {
3165         unsigned long i;
3166         struct page *page;
3167         unsigned long num_pages;
3168
3169         num_pages = num_extent_pages(eb->start, eb->len);
3170         eb->flags &= ~EXTENT_UPTODATE;
3171
3172         clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3173                               GFP_NOFS);
3174         for (i = 0; i < num_pages; i++) {
3175                 page = extent_buffer_page(eb, i);
3176                 if (page)
3177                         ClearPageUptodate(page);
3178         }
3179         return 0;
3180 }
3181
3182 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3183                                 struct extent_buffer *eb)
3184 {
3185         unsigned long i;
3186         struct page *page;
3187         unsigned long num_pages;
3188
3189         num_pages = num_extent_pages(eb->start, eb->len);
3190
3191         set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3192                             GFP_NOFS);
3193         for (i = 0; i < num_pages; i++) {
3194                 page = extent_buffer_page(eb, i);
3195                 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3196                     ((i == num_pages - 1) &&
3197                      ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3198                         check_page_uptodate(tree, page);
3199                         continue;
3200                 }
3201                 SetPageUptodate(page);
3202         }
3203         return 0;
3204 }
3205 EXPORT_SYMBOL(set_extent_buffer_uptodate);
3206
3207 int extent_range_uptodate(struct extent_io_tree *tree,
3208                           u64 start, u64 end)
3209 {
3210         struct page *page;
3211         int ret;
3212         int pg_uptodate = 1;
3213         int uptodate;
3214         unsigned long index;
3215
3216         ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
3217         if (ret)
3218                 return 1;
3219         while(start <= end) {
3220                 index = start >> PAGE_CACHE_SHIFT;
3221                 page = find_get_page(tree->mapping, index);
3222                 uptodate = PageUptodate(page);
3223                 page_cache_release(page);
3224                 if (!uptodate) {
3225                         pg_uptodate = 0;
3226                         break;
3227                 }
3228                 start += PAGE_CACHE_SIZE;
3229         }
3230         return pg_uptodate;
3231 }
3232
3233 int extent_buffer_uptodate(struct extent_io_tree *tree,
3234                            struct extent_buffer *eb)
3235 {
3236         int ret = 0;
3237         unsigned long num_pages;
3238         unsigned long i;
3239         struct page *page;
3240         int pg_uptodate = 1;
3241
3242         if (eb->flags & EXTENT_UPTODATE)
3243                 return 1;
3244
3245         ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3246                            EXTENT_UPTODATE, 1);
3247         if (ret)
3248                 return ret;
3249
3250         num_pages = num_extent_pages(eb->start, eb->len);
3251         for (i = 0; i < num_pages; i++) {
3252                 page = extent_buffer_page(eb, i);
3253                 if (!PageUptodate(page)) {
3254                         pg_uptodate = 0;
3255                         break;
3256                 }
3257         }
3258         return pg_uptodate;
3259 }
3260 EXPORT_SYMBOL(extent_buffer_uptodate);
3261
3262 int read_extent_buffer_pages(struct extent_io_tree *tree,
3263                              struct extent_buffer *eb,
3264                              u64 start, int wait,
3265                              get_extent_t *get_extent, int mirror_num)
3266 {
3267         unsigned long i;
3268         unsigned long start_i;
3269         struct page *page;
3270         int err;
3271         int ret = 0;
3272         int locked_pages = 0;
3273         int all_uptodate = 1;
3274         int inc_all_pages = 0;
3275         unsigned long num_pages;
3276         struct bio *bio = NULL;
3277         unsigned long bio_flags = 0;
3278
3279         if (eb->flags & EXTENT_UPTODATE)
3280                 return 0;
3281
3282         if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3283                            EXTENT_UPTODATE, 1)) {
3284                 return 0;
3285         }
3286
3287         if (start) {
3288                 WARN_ON(start < eb->start);
3289                 start_i = (start >> PAGE_CACHE_SHIFT) -
3290                         (eb->start >> PAGE_CACHE_SHIFT);
3291         } else {
3292                 start_i = 0;
3293         }
3294
3295         num_pages = num_extent_pages(eb->start, eb->len);
3296         for (i = start_i; i < num_pages; i++) {
3297                 page = extent_buffer_page(eb, i);
3298                 if (!wait) {
3299                         if (!trylock_page(page))
3300                                 goto unlock_exit;
3301                 } else {
3302                         lock_page(page);
3303                 }
3304                 locked_pages++;
3305                 if (!PageUptodate(page)) {
3306                         all_uptodate = 0;
3307                 }
3308         }
3309         if (all_uptodate) {
3310                 if (start_i == 0)
3311                         eb->flags |= EXTENT_UPTODATE;
3312                 if (ret) {
3313                         printk("all up to date but ret is %d\n", ret);
3314                 }
3315                 goto unlock_exit;
3316         }
3317
3318         for (i = start_i; i < num_pages; i++) {
3319                 page = extent_buffer_page(eb, i);
3320                 if (inc_all_pages)
3321                         page_cache_get(page);
3322                 if (!PageUptodate(page)) {
3323                         if (start_i == 0)
3324                                 inc_all_pages = 1;
3325                         ClearPageError(page);
3326                         err = __extent_read_full_page(tree, page,
3327                                                       get_extent, &bio,
3328                                                       mirror_num, &bio_flags);
3329                         if (err) {
3330                                 ret = err;
3331                                 printk("err %d from __extent_read_full_page\n", ret);
3332                         }
3333                 } else {
3334                         unlock_page(page);
3335                 }
3336         }
3337
3338         if (bio)
3339                 submit_one_bio(READ, bio, mirror_num, bio_flags);
3340
3341         if (ret || !wait) {
3342                 if (ret)
3343                         printk("ret %d wait %d returning\n", ret, wait);
3344                 return ret;
3345         }
3346         for (i = start_i; i < num_pages; i++) {
3347                 page = extent_buffer_page(eb, i);
3348                 wait_on_page_locked(page);
3349                 if (!PageUptodate(page)) {
3350                         printk("page not uptodate after wait_on_page_locked\n");
3351                         ret = -EIO;
3352                 }
3353         }
3354         if (!ret)
3355                 eb->flags |= EXTENT_UPTODATE;
3356         return ret;
3357
3358 unlock_exit:
3359         i = start_i;
3360         while(locked_pages > 0) {
3361                 page = extent_buffer_page(eb, i);
3362                 i++;
3363                 unlock_page(page);
3364                 locked_pages--;
3365         }
3366         return ret;
3367 }
3368 EXPORT_SYMBOL(read_extent_buffer_pages);
3369
3370 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3371                         unsigned long start,
3372                         unsigned long len)
3373 {
3374         size_t cur;
3375         size_t offset;
3376         struct page *page;
3377         char *kaddr;
3378         char *dst = (char *)dstv;
3379         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3380         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3381
3382         WARN_ON(start > eb->len);
3383         WARN_ON(start + len > eb->start + eb->len);
3384
3385         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3386
3387         while(len > 0) {
3388                 page = extent_buffer_page(eb, i);
3389
3390                 cur = min(len, (PAGE_CACHE_SIZE - offset));
3391                 kaddr = kmap_atomic(page, KM_USER1);
3392                 memcpy(dst, kaddr + offset, cur);
3393                 kunmap_atomic(kaddr, KM_USER1);
3394
3395                 dst += cur;
3396                 len -= cur;
3397                 offset = 0;
3398                 i++;
3399         }
3400 }
3401 EXPORT_SYMBOL(read_extent_buffer);
3402
3403 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3404                                unsigned long min_len, char **token, char **map,
3405                                unsigned long *map_start,
3406                                unsigned long *map_len, int km)
3407 {
3408         size_t offset = start & (PAGE_CACHE_SIZE - 1);
3409         char *kaddr;
3410         struct page *p;
3411         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3412         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3413         unsigned long end_i = (start_offset + start + min_len - 1) >>
3414                 PAGE_CACHE_SHIFT;
3415
3416         if (i != end_i)
3417                 return -EINVAL;
3418
3419         if (i == 0) {
3420                 offset = start_offset;
3421                 *map_start = 0;
3422         } else {
3423                 offset = 0;
3424                 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3425         }
3426         if (start + min_len > eb->len) {
3427 printk("bad mapping eb start %Lu len %lu, wanted %lu %lu\n", eb->start, eb->len, start, min_len);
3428                 WARN_ON(1);
3429         }
3430
3431         p = extent_buffer_page(eb, i);
3432         kaddr = kmap_atomic(p, km);
3433         *token = kaddr;
3434         *map = kaddr + offset;
3435         *map_len = PAGE_CACHE_SIZE - offset;
3436         return 0;
3437 }
3438 EXPORT_SYMBOL(map_private_extent_buffer);
3439
3440 int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
3441                       unsigned long min_len,
3442                       char **token, char **map,
3443                       unsigned long *map_start,
3444                       unsigned long *map_len, int km)
3445 {
3446         int err;
3447         int save = 0;
3448         if (eb->map_token) {
3449                 unmap_extent_buffer(eb, eb->map_token, km);
3450                 eb->map_token = NULL;
3451                 save = 1;
3452         }
3453         err = map_private_extent_buffer(eb, start, min_len, token, map,
3454                                        map_start, map_len, km);
3455         if (!err && save) {
3456                 eb->map_token = *token;
3457                 eb->kaddr = *map;
3458                 eb->map_start = *map_start;
3459                 eb->map_len = *map_len;
3460         }
3461         return err;
3462 }
3463 EXPORT_SYMBOL(map_extent_buffer);
3464
3465 void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
3466 {
3467         kunmap_atomic(token, km);
3468 }
3469 EXPORT_SYMBOL(unmap_extent_buffer);
3470
3471 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3472                           unsigned long start,
3473                           unsigned long len)
3474 {
3475         size_t cur;
3476         size_t offset;
3477         struct page *page;
3478         char *kaddr;
3479         char *ptr = (char *)ptrv;
3480         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3481         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3482         int ret = 0;
3483
3484         WARN_ON(start > eb->len);
3485         WARN_ON(start + len > eb->start + eb->len);
3486
3487         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3488
3489         while(len > 0) {
3490                 page = extent_buffer_page(eb, i);
3491
3492                 cur = min(len, (PAGE_CACHE_SIZE - offset));
3493
3494                 kaddr = kmap_atomic(page, KM_USER0);
3495                 ret = memcmp(ptr, kaddr + offset, cur);
3496                 kunmap_atomic(kaddr, KM_USER0);
3497                 if (ret)
3498                         break;
3499
3500                 ptr += cur;
3501                 len -= cur;
3502                 offset = 0;
3503                 i++;
3504         }
3505         return ret;
3506 }
3507 EXPORT_SYMBOL(memcmp_extent_buffer);
3508
3509 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3510                          unsigned long start, unsigned long len)
3511 {
3512         size_t cur;
3513         size_t offset;
3514         struct page *page;
3515         char *kaddr;
3516         char *src = (char *)srcv;
3517         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3518         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3519
3520         WARN_ON(start > eb->len);
3521         WARN_ON(start + len > eb->start + eb->len);
3522
3523         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3524
3525         while(len > 0) {
3526                 page = extent_buffer_page(eb, i);
3527                 WARN_ON(!PageUptodate(page));
3528
3529                 cur = min(len, PAGE_CACHE_SIZE - offset);
3530                 kaddr = kmap_atomic(page, KM_USER1);
3531                 memcpy(kaddr + offset, src, cur);
3532                 kunmap_atomic(kaddr, KM_USER1);
3533
3534                 src += cur;
3535                 len -= cur;
3536                 offset = 0;
3537                 i++;
3538         }
3539 }
3540 EXPORT_SYMBOL(write_extent_buffer);
3541
3542 void memset_extent_buffer(struct extent_buffer *eb, char c,
3543                           unsigned long start, unsigned long len)
3544 {
3545         size_t cur;
3546         size_t offset;
3547         struct page *page;
3548         char *kaddr;
3549         size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3550         unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3551
3552         WARN_ON(start > eb->len);
3553         WARN_ON(start + len > eb->start + eb->len);
3554
3555         offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3556
3557         while(len > 0) {
3558                 page = extent_buffer_page(eb, i);
3559                 WARN_ON(!PageUptodate(page));
3560
3561                 cur = min(len, PAGE_CACHE_SIZE - offset);
3562                 kaddr = kmap_atomic(page, KM_USER0);
3563                 memset(kaddr + offset, c, cur);
3564                 kunmap_atomic(kaddr, KM_USER0);
3565
3566                 len -= cur;
3567                 offset = 0;
3568                 i++;
3569         }
3570 }
3571 EXPORT_SYMBOL(memset_extent_buffer);
3572
3573 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3574                         unsigned long dst_offset, unsigned long src_offset,
3575                         unsigned long len)
3576 {
3577         u64 dst_len = dst->len;
3578         size_t cur;
3579         size_t offset;
3580         struct page *page;
3581         char *kaddr;
3582         size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3583         unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3584
3585         WARN_ON(src->len != dst_len);
3586
3587         offset = (start_offset + dst_offset) &
3588                 ((unsigned long)PAGE_CACHE_SIZE - 1);
3589
3590         while(len > 0) {
3591                 page = extent_buffer_page(dst, i);
3592                 WARN_ON(!PageUptodate(page));
3593
3594                 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3595
3596                 kaddr = kmap_atomic(page, KM_USER0);
3597                 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3598                 kunmap_atomic(kaddr, KM_USER0);
3599
3600                 src_offset += cur;
3601                 len -= cur;
3602                 offset = 0;
3603                 i++;
3604         }
3605 }
3606 EXPORT_SYMBOL(copy_extent_buffer);
3607
3608 static void move_pages(struct page *dst_page, struct page *src_page,
3609                        unsigned long dst_off, unsigned long src_off,
3610                        unsigned long len)
3611 {
3612         char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3613         if (dst_page == src_page) {
3614                 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3615         } else {
3616                 char *src_kaddr = kmap_atomic(src_page, KM_USER1);
3617                 char *p = dst_kaddr + dst_off + len;
3618                 char *s = src_kaddr + src_off + len;
3619
3620                 while (len--)
3621                         *--p = *--s;
3622
3623                 kunmap_atomic(src_kaddr, KM_USER1);
3624         }
3625         kunmap_atomic(dst_kaddr, KM_USER0);
3626 }
3627
3628 static void copy_pages(struct page *dst_page, struct page *src_page,
3629                        unsigned long dst_off, unsigned long src_off,
3630                        unsigned long len)
3631 {
3632         char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3633         char *src_kaddr;
3634
3635         if (dst_page != src_page)
3636                 src_kaddr = kmap_atomic(src_page, KM_USER1);
3637         else
3638                 src_kaddr = dst_kaddr;
3639
3640         memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3641         kunmap_atomic(dst_kaddr, KM_USER0);
3642         if (dst_page != src_page)
3643                 kunmap_atomic(src_kaddr, KM_USER1);
3644 }
3645
3646 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3647                            unsigned long src_offset, unsigned long len)
3648 {
3649         size_t cur;
3650         size_t dst_off_in_page;
3651         size_t src_off_in_page;
3652         size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3653         unsigned long dst_i;
3654         unsigned long src_i;
3655
3656         if (src_offset + len > dst->len) {
3657                 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3658                        src_offset, len, dst->len);
3659                 BUG_ON(1);
3660         }
3661         if (dst_offset + len > dst->len) {
3662                 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3663                        dst_offset, len, dst->len);
3664                 BUG_ON(1);
3665         }
3666
3667         while(len > 0) {
3668                 dst_off_in_page = (start_offset + dst_offset) &
3669                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3670                 src_off_in_page = (start_offset + src_offset) &
3671                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3672
3673                 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3674                 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3675
3676                 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3677                                                src_off_in_page));
3678                 cur = min_t(unsigned long, cur,
3679                         (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3680
3681                 copy_pages(extent_buffer_page(dst, dst_i),
3682                            extent_buffer_page(dst, src_i),
3683                            dst_off_in_page, src_off_in_page, cur);
3684
3685                 src_offset += cur;
3686                 dst_offset += cur;
3687                 len -= cur;
3688         }
3689 }
3690 EXPORT_SYMBOL(memcpy_extent_buffer);
3691
3692 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3693                            unsigned long src_offset, unsigned long len)
3694 {
3695         size_t cur;
3696         size_t dst_off_in_page;
3697         size_t src_off_in_page;
3698         unsigned long dst_end = dst_offset + len - 1;
3699         unsigned long src_end = src_offset + len - 1;
3700         size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3701         unsigned long dst_i;
3702         unsigned long src_i;
3703
3704         if (src_offset + len > dst->len) {
3705                 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3706                        src_offset, len, dst->len);
3707                 BUG_ON(1);
3708         }
3709         if (dst_offset + len > dst->len) {
3710                 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3711                        dst_offset, len, dst->len);
3712                 BUG_ON(1);
3713         }
3714         if (dst_offset < src_offset) {
3715                 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3716                 return;
3717         }
3718         while(len > 0) {
3719                 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3720                 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3721
3722                 dst_off_in_page = (start_offset + dst_end) &
3723                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3724                 src_off_in_page = (start_offset + src_end) &
3725                         ((unsigned long)PAGE_CACHE_SIZE - 1);
3726
3727                 cur = min_t(unsigned long, len, src_off_in_page + 1);
3728                 cur = min(cur, dst_off_in_page + 1);
3729                 move_pages(extent_buffer_page(dst, dst_i),
3730                            extent_buffer_page(dst, src_i),
3731                            dst_off_in_page - cur + 1,
3732                            src_off_in_page - cur + 1, cur);
3733
3734                 dst_end -= cur;
3735                 src_end -= cur;
3736                 len -= cur;
3737         }
3738 }
3739 EXPORT_SYMBOL(memmove_extent_buffer);
3740
3741 int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3742 {
3743         u64 start = page_offset(page);
3744         struct extent_buffer *eb;
3745         int ret = 1;
3746         unsigned long i;
3747         unsigned long num_pages;
3748
3749         spin_lock(&tree->buffer_lock);
3750         eb = buffer_search(tree, start);
3751         if (!eb)
3752                 goto out;
3753
3754         if (atomic_read(&eb->refs) > 1) {
3755                 ret = 0;
3756                 goto out;
3757         }
3758         /* at this point we can safely release the extent buffer */
3759         num_pages = num_extent_pages(eb->start, eb->len);
3760         for (i = 0; i < num_pages; i++)
3761                 page_cache_release(extent_buffer_page(eb, i));
3762         rb_erase(&eb->rb_node, &tree->buffer);
3763         __free_extent_buffer(eb);
3764 out:
3765         spin_unlock(&tree->buffer_lock);
3766         return ret;
3767 }
3768 EXPORT_SYMBOL(try_release_extent_buffer);