1#include <linux/bitops.h>
   2#include <linux/slab.h>
   3#include <linux/bio.h>
   4#include <linux/mm.h>
   5#include <linux/pagemap.h>
   6#include <linux/page-flags.h>
   7#include <linux/module.h>
   8#include <linux/spinlock.h>
   9#include <linux/blkdev.h>
  10#include <linux/swap.h>
  11#include <linux/writeback.h>
  12#include <linux/pagevec.h>
  13#include <linux/prefetch.h>
  14#include <linux/cleancache.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#include "volumes.h"
  21#include "check-integrity.h"
  22#include "locking.h"
  23#include "rcu-string.h"
 
  24
  25static struct kmem_cache *extent_state_cache;
  26static struct kmem_cache *extent_buffer_cache;
 
  27
 
 
 
 
 
 
  28static LIST_HEAD(buffers);
  29static LIST_HEAD(states);
  30
  31#define LEAK_DEBUG 0
  32#if LEAK_DEBUG
  33static DEFINE_SPINLOCK(leak_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  34#endif
  35
  36#define BUFFER_LRU_MAX 64
  37
  38struct tree_entry {
  39	u64 start;
  40	u64 end;
  41	struct rb_node rb_node;
  42};
  43
  44struct extent_page_data {
  45	struct bio *bio;
  46	struct extent_io_tree *tree;
  47	get_extent_t *get_extent;
 
  48
  49	/* tells writepage not to lock the state bits for this range
  50	 * it still does the unlocking
  51	 */
  52	unsigned int extent_locked:1;
  53
  54	/* tells the submit_bio code to use a WRITE_SYNC */
  55	unsigned int sync_io:1;
  56};
  57
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  58static noinline void flush_write_bio(void *data);
  59static inline struct btrfs_fs_info *
  60tree_fs_info(struct extent_io_tree *tree)
  61{
 
 
  62	return btrfs_sb(tree->mapping->host->i_sb);
  63}
  64
  65int __init extent_io_init(void)
  66{
  67	extent_state_cache = kmem_cache_create("extent_state",
  68			sizeof(struct extent_state), 0,
  69			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
  70	if (!extent_state_cache)
  71		return -ENOMEM;
  72
  73	extent_buffer_cache = kmem_cache_create("extent_buffers",
  74			sizeof(struct extent_buffer), 0,
  75			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
  76	if (!extent_buffer_cache)
  77		goto free_state_cache;
 
 
 
 
 
 
 
 
 
  78	return 0;
  79
 
 
 
 
 
 
 
 
  80free_state_cache:
  81	kmem_cache_destroy(extent_state_cache);
 
  82	return -ENOMEM;
  83}
  84
  85void extent_io_exit(void)
  86{
  87	struct extent_state *state;
  88	struct extent_buffer *eb;
  89
  90	while (!list_empty(&states)) {
  91		state = list_entry(states.next, struct extent_state, leak_list);
  92		printk(KERN_ERR "btrfs state leak: start %llu end %llu "
  93		       "state %lu in tree %p refs %d\n",
  94		       (unsigned long long)state->start,
  95		       (unsigned long long)state->end,
  96		       state->state, state->tree, atomic_read(&state->refs));
  97		list_del(&state->leak_list);
  98		kmem_cache_free(extent_state_cache, state);
  99
 100	}
 101
 102	while (!list_empty(&buffers)) {
 103		eb = list_entry(buffers.next, struct extent_buffer, leak_list);
 104		printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
 105		       "refs %d\n", (unsigned long long)eb->start,
 106		       eb->len, atomic_read(&eb->refs));
 107		list_del(&eb->leak_list);
 108		kmem_cache_free(extent_buffer_cache, eb);
 109	}
 110	if (extent_state_cache)
 111		kmem_cache_destroy(extent_state_cache);
 112	if (extent_buffer_cache)
 113		kmem_cache_destroy(extent_buffer_cache);
 114}
 115
 116void extent_io_tree_init(struct extent_io_tree *tree,
 117			 struct address_space *mapping)
 118{
 119	tree->state = RB_ROOT;
 120	INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
 121	tree->ops = NULL;
 122	tree->dirty_bytes = 0;
 123	spin_lock_init(&tree->lock);
 124	spin_lock_init(&tree->buffer_lock);
 125	tree->mapping = mapping;
 126}
 127
 128static struct extent_state *alloc_extent_state(gfp_t mask)
 129{
 130	struct extent_state *state;
 131#if LEAK_DEBUG
 132	unsigned long flags;
 133#endif
 134
 135	state = kmem_cache_alloc(extent_state_cache, mask);
 136	if (!state)
 137		return state;
 138	state->state = 0;
 139	state->private = 0;
 140	state->tree = NULL;
 141#if LEAK_DEBUG
 142	spin_lock_irqsave(&leak_lock, flags);
 143	list_add(&state->leak_list, &states);
 144	spin_unlock_irqrestore(&leak_lock, flags);
 145#endif
 146	atomic_set(&state->refs, 1);
 147	init_waitqueue_head(&state->wq);
 148	trace_alloc_extent_state(state, mask, _RET_IP_);
 149	return state;
 150}
 151
 152void free_extent_state(struct extent_state *state)
 153{
 154	if (!state)
 155		return;
 156	if (atomic_dec_and_test(&state->refs)) {
 157#if LEAK_DEBUG
 158		unsigned long flags;
 159#endif
 160		WARN_ON(state->tree);
 161#if LEAK_DEBUG
 162		spin_lock_irqsave(&leak_lock, flags);
 163		list_del(&state->leak_list);
 164		spin_unlock_irqrestore(&leak_lock, flags);
 165#endif
 166		trace_free_extent_state(state, _RET_IP_);
 167		kmem_cache_free(extent_state_cache, state);
 168	}
 169}
 170
 171static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
 172				   struct rb_node *node)
 
 
 
 
 173{
 174	struct rb_node **p = &root->rb_node;
 175	struct rb_node *parent = NULL;
 176	struct tree_entry *entry;
 177
 
 
 
 
 
 
 
 178	while (*p) {
 179		parent = *p;
 180		entry = rb_entry(parent, struct tree_entry, rb_node);
 181
 182		if (offset < entry->start)
 183			p = &(*p)->rb_left;
 184		else if (offset > entry->end)
 185			p = &(*p)->rb_right;
 186		else
 187			return parent;
 188	}
 189
 
 190	rb_link_node(node, parent, p);
 191	rb_insert_color(node, root);
 192	return NULL;
 193}
 194
 195static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
 196				     struct rb_node **prev_ret,
 197				     struct rb_node **next_ret)
 
 
 198{
 199	struct rb_root *root = &tree->state;
 200	struct rb_node *n = root->rb_node;
 201	struct rb_node *prev = NULL;
 202	struct rb_node *orig_prev = NULL;
 203	struct tree_entry *entry;
 204	struct tree_entry *prev_entry = NULL;
 205
 206	while (n) {
 207		entry = rb_entry(n, struct tree_entry, rb_node);
 208		prev = n;
 209		prev_entry = entry;
 210
 211		if (offset < entry->start)
 212			n = n->rb_left;
 213		else if (offset > entry->end)
 214			n = n->rb_right;
 215		else
 216			return n;
 217	}
 218
 
 
 
 
 
 219	if (prev_ret) {
 220		orig_prev = prev;
 221		while (prev && offset > prev_entry->end) {
 222			prev = rb_next(prev);
 223			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 224		}
 225		*prev_ret = prev;
 226		prev = orig_prev;
 227	}
 228
 229	if (next_ret) {
 230		prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 231		while (prev && offset < prev_entry->start) {
 232			prev = rb_prev(prev);
 233			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 234		}
 235		*next_ret = prev;
 236	}
 237	return NULL;
 238}
 239
 240static inline struct rb_node *tree_search(struct extent_io_tree *tree,
 241					  u64 offset)
 
 
 
 242{
 243	struct rb_node *prev = NULL;
 244	struct rb_node *ret;
 245
 246	ret = __etree_search(tree, offset, &prev, NULL);
 247	if (!ret)
 248		return prev;
 249	return ret;
 250}
 251
 
 
 
 
 
 
 252static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
 253		     struct extent_state *other)
 254{
 255	if (tree->ops && tree->ops->merge_extent_hook)
 256		tree->ops->merge_extent_hook(tree->mapping->host, new,
 257					     other);
 258}
 259
 260/*
 261 * utility function to look for merge candidates inside a given range.
 262 * Any extents with matching state are merged together into a single
 263 * extent in the tree.  Extents with EXTENT_IO in their state field
 264 * are not merged because the end_io handlers need to be able to do
 265 * operations on them without sleeping (or doing allocations/splits).
 266 *
 267 * This should be called with the tree lock held.
 268 */
 269static void merge_state(struct extent_io_tree *tree,
 270		        struct extent_state *state)
 271{
 272	struct extent_state *other;
 273	struct rb_node *other_node;
 274
 275	if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
 276		return;
 277
 278	other_node = rb_prev(&state->rb_node);
 279	if (other_node) {
 280		other = rb_entry(other_node, struct extent_state, rb_node);
 281		if (other->end == state->start - 1 &&
 282		    other->state == state->state) {
 283			merge_cb(tree, state, other);
 284			state->start = other->start;
 285			other->tree = NULL;
 286			rb_erase(&other->rb_node, &tree->state);
 
 287			free_extent_state(other);
 288		}
 289	}
 290	other_node = rb_next(&state->rb_node);
 291	if (other_node) {
 292		other = rb_entry(other_node, struct extent_state, rb_node);
 293		if (other->start == state->end + 1 &&
 294		    other->state == state->state) {
 295			merge_cb(tree, state, other);
 296			state->end = other->end;
 297			other->tree = NULL;
 298			rb_erase(&other->rb_node, &tree->state);
 
 299			free_extent_state(other);
 300		}
 301	}
 302}
 303
 304static void set_state_cb(struct extent_io_tree *tree,
 305			 struct extent_state *state, int *bits)
 306{
 307	if (tree->ops && tree->ops->set_bit_hook)
 308		tree->ops->set_bit_hook(tree->mapping->host, state, bits);
 309}
 310
 311static void clear_state_cb(struct extent_io_tree *tree,
 312			   struct extent_state *state, int *bits)
 313{
 314	if (tree->ops && tree->ops->clear_bit_hook)
 315		tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
 316}
 317
 318static void set_state_bits(struct extent_io_tree *tree,
 319			   struct extent_state *state, int *bits);
 
 320
 321/*
 322 * insert an extent_state struct into the tree.  'bits' are set on the
 323 * struct before it is inserted.
 324 *
 325 * This may return -EEXIST if the extent is already there, in which case the
 326 * state struct is freed.
 327 *
 328 * The tree lock is not taken internally.  This is a utility function and
 329 * probably isn't what you want to call (see set/clear_extent_bit).
 330 */
 331static int insert_state(struct extent_io_tree *tree,
 332			struct extent_state *state, u64 start, u64 end,
 333			int *bits)
 
 
 334{
 335	struct rb_node *node;
 336
 337	if (end < start) {
 338		printk(KERN_ERR "btrfs end < start %llu %llu\n",
 339		       (unsigned long long)end,
 340		       (unsigned long long)start);
 341		WARN_ON(1);
 342	}
 343	state->start = start;
 344	state->end = end;
 345
 346	set_state_bits(tree, state, bits);
 347
 348	node = tree_insert(&tree->state, end, &state->rb_node);
 349	if (node) {
 350		struct extent_state *found;
 351		found = rb_entry(node, struct extent_state, rb_node);
 352		printk(KERN_ERR "btrfs found node %llu %llu on insert of "
 353		       "%llu %llu\n", (unsigned long long)found->start,
 354		       (unsigned long long)found->end,
 355		       (unsigned long long)start, (unsigned long long)end);
 356		return -EEXIST;
 357	}
 358	state->tree = tree;
 359	merge_state(tree, state);
 360	return 0;
 361}
 362
 363static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
 364		     u64 split)
 365{
 366	if (tree->ops && tree->ops->split_extent_hook)
 367		tree->ops->split_extent_hook(tree->mapping->host, orig, split);
 368}
 369
 370/*
 371 * split a given extent state struct in two, inserting the preallocated
 372 * struct 'prealloc' as the newly created second half.  'split' indicates an
 373 * offset inside 'orig' where it should be split.
 374 *
 375 * Before calling,
 376 * the tree has 'orig' at [orig->start, orig->end].  After calling, there
 377 * are two extent state structs in the tree:
 378 * prealloc: [orig->start, split - 1]
 379 * orig: [ split, orig->end ]
 380 *
 381 * The tree locks are not taken by this function. They need to be held
 382 * by the caller.
 383 */
 384static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 385		       struct extent_state *prealloc, u64 split)
 386{
 387	struct rb_node *node;
 388
 389	split_cb(tree, orig, split);
 390
 391	prealloc->start = orig->start;
 392	prealloc->end = split - 1;
 393	prealloc->state = orig->state;
 394	orig->start = split;
 395
 396	node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
 
 397	if (node) {
 398		free_extent_state(prealloc);
 399		return -EEXIST;
 400	}
 401	prealloc->tree = tree;
 402	return 0;
 403}
 404
 405static struct extent_state *next_state(struct extent_state *state)
 406{
 407	struct rb_node *next = rb_next(&state->rb_node);
 408	if (next)
 409		return rb_entry(next, struct extent_state, rb_node);
 410	else
 411		return NULL;
 412}
 413
 414/*
 415 * utility function to clear some bits in an extent state struct.
 416 * it will optionally wake up any one waiting on this state (wake == 1).
 417 *
 418 * If no bits are set on the state struct after clearing things, the
 419 * struct is freed and removed from the tree
 420 */
 421static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
 422					    struct extent_state *state,
 423					    int *bits, int wake)
 
 424{
 425	struct extent_state *next;
 426	int bits_to_clear = *bits & ~EXTENT_CTLBITS;
 427
 428	if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
 429		u64 range = state->end - state->start + 1;
 430		WARN_ON(range > tree->dirty_bytes);
 431		tree->dirty_bytes -= range;
 432	}
 433	clear_state_cb(tree, state, bits);
 
 434	state->state &= ~bits_to_clear;
 435	if (wake)
 436		wake_up(&state->wq);
 437	if (state->state == 0) {
 438		next = next_state(state);
 439		if (state->tree) {
 440			rb_erase(&state->rb_node, &tree->state);
 441			state->tree = NULL;
 442			free_extent_state(state);
 443		} else {
 444			WARN_ON(1);
 445		}
 446	} else {
 447		merge_state(tree, state);
 448		next = next_state(state);
 449	}
 450	return next;
 451}
 452
 453static struct extent_state *
 454alloc_extent_state_atomic(struct extent_state *prealloc)
 455{
 456	if (!prealloc)
 457		prealloc = alloc_extent_state(GFP_ATOMIC);
 458
 459	return prealloc;
 460}
 461
 462void extent_io_tree_panic(struct extent_io_tree *tree, int err)
 463{
 464	btrfs_panic(tree_fs_info(tree), err, "Locking error: "
 465		    "Extent tree was modified by another "
 466		    "thread while locked.");
 467}
 468
 469/*
 470 * clear some bits on a range in the tree.  This may require splitting
 471 * or inserting elements in the tree, so the gfp mask is used to
 472 * indicate which allocations or sleeping are allowed.
 473 *
 474 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
 475 * the given range from the tree regardless of state (ie for truncate).
 476 *
 477 * the range [start, end] is inclusive.
 478 *
 479 * This takes the tree lock, and returns 0 on success and < 0 on error.
 480 */
 481int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 482		     int bits, int wake, int delete,
 483		     struct extent_state **cached_state,
 484		     gfp_t mask)
 485{
 486	struct extent_state *state;
 487	struct extent_state *cached;
 488	struct extent_state *prealloc = NULL;
 489	struct rb_node *node;
 490	u64 last_end;
 491	int err;
 492	int clear = 0;
 493
 
 
 
 
 
 494	if (delete)
 495		bits |= ~EXTENT_CTLBITS;
 496	bits |= EXTENT_FIRST_DELALLOC;
 497
 498	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
 499		clear = 1;
 500again:
 501	if (!prealloc && (mask & __GFP_WAIT)) {
 
 
 
 
 
 
 
 502		prealloc = alloc_extent_state(mask);
 503		if (!prealloc)
 504			return -ENOMEM;
 505	}
 506
 507	spin_lock(&tree->lock);
 508	if (cached_state) {
 509		cached = *cached_state;
 510
 511		if (clear) {
 512			*cached_state = NULL;
 513			cached_state = NULL;
 514		}
 515
 516		if (cached && cached->tree && cached->start <= start &&
 517		    cached->end > start) {
 518			if (clear)
 519				atomic_dec(&cached->refs);
 520			state = cached;
 521			goto hit_next;
 522		}
 523		if (clear)
 524			free_extent_state(cached);
 525	}
 526	/*
 527	 * this search will find the extents that end after
 528	 * our range starts
 529	 */
 530	node = tree_search(tree, start);
 531	if (!node)
 532		goto out;
 533	state = rb_entry(node, struct extent_state, rb_node);
 534hit_next:
 535	if (state->start > end)
 536		goto out;
 537	WARN_ON(state->end < start);
 538	last_end = state->end;
 539
 540	/* the state doesn't have the wanted bits, go ahead */
 541	if (!(state->state & bits)) {
 542		state = next_state(state);
 543		goto next;
 544	}
 545
 546	/*
 547	 *     | ---- desired range ---- |
 548	 *  | state | or
 549	 *  | ------------- state -------------- |
 550	 *
 551	 * We need to split the extent we found, and may flip
 552	 * bits on second half.
 553	 *
 554	 * If the extent we found extends past our range, we
 555	 * just split and search again.  It'll get split again
 556	 * the next time though.
 557	 *
 558	 * If the extent we found is inside our range, we clear
 559	 * the desired bit on it.
 560	 */
 561
 562	if (state->start < start) {
 563		prealloc = alloc_extent_state_atomic(prealloc);
 564		BUG_ON(!prealloc);
 565		err = split_state(tree, state, prealloc, start);
 566		if (err)
 567			extent_io_tree_panic(tree, err);
 568
 569		prealloc = NULL;
 570		if (err)
 571			goto out;
 572		if (state->end <= end) {
 573			state = clear_state_bit(tree, state, &bits, wake);
 
 574			goto next;
 575		}
 576		goto search_again;
 577	}
 578	/*
 579	 * | ---- desired range ---- |
 580	 *                        | state |
 581	 * We need to split the extent, and clear the bit
 582	 * on the first half
 583	 */
 584	if (state->start <= end && state->end > end) {
 585		prealloc = alloc_extent_state_atomic(prealloc);
 586		BUG_ON(!prealloc);
 587		err = split_state(tree, state, prealloc, end + 1);
 588		if (err)
 589			extent_io_tree_panic(tree, err);
 590
 591		if (wake)
 592			wake_up(&state->wq);
 593
 594		clear_state_bit(tree, prealloc, &bits, wake);
 595
 596		prealloc = NULL;
 597		goto out;
 598	}
 599
 600	state = clear_state_bit(tree, state, &bits, wake);
 601next:
 602	if (last_end == (u64)-1)
 603		goto out;
 604	start = last_end + 1;
 605	if (start <= end && state && !need_resched())
 606		goto hit_next;
 607	goto search_again;
 608
 609out:
 610	spin_unlock(&tree->lock);
 611	if (prealloc)
 612		free_extent_state(prealloc);
 613
 614	return 0;
 615
 616search_again:
 617	if (start > end)
 618		goto out;
 619	spin_unlock(&tree->lock);
 620	if (mask & __GFP_WAIT)
 621		cond_resched();
 622	goto again;
 623}
 624
 625static void wait_on_state(struct extent_io_tree *tree,
 626			  struct extent_state *state)
 627		__releases(tree->lock)
 628		__acquires(tree->lock)
 629{
 630	DEFINE_WAIT(wait);
 631	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
 632	spin_unlock(&tree->lock);
 633	schedule();
 634	spin_lock(&tree->lock);
 635	finish_wait(&state->wq, &wait);
 636}
 637
 638/*
 639 * waits for one or more bits to clear on a range in the state tree.
 640 * The range [start, end] is inclusive.
 641 * The tree lock is taken by this function
 642 */
 643void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
 
 644{
 645	struct extent_state *state;
 646	struct rb_node *node;
 647
 
 
 648	spin_lock(&tree->lock);
 649again:
 650	while (1) {
 651		/*
 652		 * this search will find all the extents that end after
 653		 * our range starts
 654		 */
 655		node = tree_search(tree, start);
 
 656		if (!node)
 657			break;
 658
 659		state = rb_entry(node, struct extent_state, rb_node);
 660
 661		if (state->start > end)
 662			goto out;
 663
 664		if (state->state & bits) {
 665			start = state->start;
 666			atomic_inc(&state->refs);
 667			wait_on_state(tree, state);
 668			free_extent_state(state);
 669			goto again;
 670		}
 671		start = state->end + 1;
 672
 673		if (start > end)
 674			break;
 675
 676		cond_resched_lock(&tree->lock);
 
 
 
 677	}
 678out:
 679	spin_unlock(&tree->lock);
 680}
 681
 682static void set_state_bits(struct extent_io_tree *tree,
 683			   struct extent_state *state,
 684			   int *bits)
 685{
 686	int bits_to_set = *bits & ~EXTENT_CTLBITS;
 687
 688	set_state_cb(tree, state, bits);
 689	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
 690		u64 range = state->end - state->start + 1;
 691		tree->dirty_bytes += range;
 692	}
 
 693	state->state |= bits_to_set;
 694}
 695
 696static void cache_state(struct extent_state *state,
 697			struct extent_state **cached_ptr)
 
 698{
 699	if (cached_ptr && !(*cached_ptr)) {
 700		if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
 701			*cached_ptr = state;
 702			atomic_inc(&state->refs);
 703		}
 704	}
 705}
 706
 707static void uncache_state(struct extent_state **cached_ptr)
 
 708{
 709	if (cached_ptr && (*cached_ptr)) {
 710		struct extent_state *state = *cached_ptr;
 711		*cached_ptr = NULL;
 712		free_extent_state(state);
 713	}
 714}
 715
 716/*
 717 * set some bits on a range in the tree.  This may require allocations or
 718 * sleeping, so the gfp mask is used to indicate what is allowed.
 719 *
 720 * If any of the exclusive bits are set, this will fail with -EEXIST if some
 721 * part of the range already has the desired bits set.  The start of the
 722 * existing range is returned in failed_start in this case.
 723 *
 724 * [start, end] is inclusive This takes the tree lock.
 725 */
 726
 727static int __must_check
 728__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 729		 int bits, int exclusive_bits, u64 *failed_start,
 730		 struct extent_state **cached_state, gfp_t mask)
 
 731{
 732	struct extent_state *state;
 733	struct extent_state *prealloc = NULL;
 734	struct rb_node *node;
 
 
 735	int err = 0;
 736	u64 last_start;
 737	u64 last_end;
 738
 
 
 739	bits |= EXTENT_FIRST_DELALLOC;
 740again:
 741	if (!prealloc && (mask & __GFP_WAIT)) {
 742		prealloc = alloc_extent_state(mask);
 743		BUG_ON(!prealloc);
 744	}
 745
 746	spin_lock(&tree->lock);
 747	if (cached_state && *cached_state) {
 748		state = *cached_state;
 749		if (state->start <= start && state->end > start &&
 750		    state->tree) {
 751			node = &state->rb_node;
 752			goto hit_next;
 753		}
 754	}
 755	/*
 756	 * this search will find all the extents that end after
 757	 * our range starts.
 758	 */
 759	node = tree_search(tree, start);
 760	if (!node) {
 761		prealloc = alloc_extent_state_atomic(prealloc);
 762		BUG_ON(!prealloc);
 763		err = insert_state(tree, prealloc, start, end, &bits);
 
 764		if (err)
 765			extent_io_tree_panic(tree, err);
 766
 
 767		prealloc = NULL;
 768		goto out;
 769	}
 770	state = rb_entry(node, struct extent_state, rb_node);
 771hit_next:
 772	last_start = state->start;
 773	last_end = state->end;
 774
 775	/*
 776	 * | ---- desired range ---- |
 777	 * | state |
 778	 *
 779	 * Just lock what we found and keep going
 780	 */
 781	if (state->start == start && state->end <= end) {
 782		if (state->state & exclusive_bits) {
 783			*failed_start = state->start;
 784			err = -EEXIST;
 785			goto out;
 786		}
 787
 788		set_state_bits(tree, state, &bits);
 789		cache_state(state, cached_state);
 790		merge_state(tree, state);
 791		if (last_end == (u64)-1)
 792			goto out;
 793		start = last_end + 1;
 794		state = next_state(state);
 795		if (start < end && state && state->start == start &&
 796		    !need_resched())
 797			goto hit_next;
 798		goto search_again;
 799	}
 800
 801	/*
 802	 *     | ---- desired range ---- |
 803	 * | state |
 804	 *   or
 805	 * | ------------- state -------------- |
 806	 *
 807	 * We need to split the extent we found, and may flip bits on
 808	 * second half.
 809	 *
 810	 * If the extent we found extends past our
 811	 * range, we just split and search again.  It'll get split
 812	 * again the next time though.
 813	 *
 814	 * If the extent we found is inside our range, we set the
 815	 * desired bit on it.
 816	 */
 817	if (state->start < start) {
 818		if (state->state & exclusive_bits) {
 819			*failed_start = start;
 820			err = -EEXIST;
 821			goto out;
 822		}
 823
 824		prealloc = alloc_extent_state_atomic(prealloc);
 825		BUG_ON(!prealloc);
 826		err = split_state(tree, state, prealloc, start);
 827		if (err)
 828			extent_io_tree_panic(tree, err);
 829
 830		prealloc = NULL;
 831		if (err)
 832			goto out;
 833		if (state->end <= end) {
 834			set_state_bits(tree, state, &bits);
 835			cache_state(state, cached_state);
 836			merge_state(tree, state);
 837			if (last_end == (u64)-1)
 838				goto out;
 839			start = last_end + 1;
 840			state = next_state(state);
 841			if (start < end && state && state->start == start &&
 842			    !need_resched())
 843				goto hit_next;
 844		}
 845		goto search_again;
 846	}
 847	/*
 848	 * | ---- desired range ---- |
 849	 *     | state | or               | state |
 850	 *
 851	 * There's a hole, we need to insert something in it and
 852	 * ignore the extent we found.
 853	 */
 854	if (state->start > start) {
 855		u64 this_end;
 856		if (end < last_start)
 857			this_end = end;
 858		else
 859			this_end = last_start - 1;
 860
 861		prealloc = alloc_extent_state_atomic(prealloc);
 862		BUG_ON(!prealloc);
 863
 864		/*
 865		 * Avoid to free 'prealloc' if it can be merged with
 866		 * the later extent.
 867		 */
 868		err = insert_state(tree, prealloc, start, this_end,
 869				   &bits);
 870		if (err)
 871			extent_io_tree_panic(tree, err);
 872
 873		cache_state(prealloc, cached_state);
 874		prealloc = NULL;
 875		start = this_end + 1;
 876		goto search_again;
 877	}
 878	/*
 879	 * | ---- desired range ---- |
 880	 *                        | state |
 881	 * We need to split the extent, and set the bit
 882	 * on the first half
 883	 */
 884	if (state->start <= end && state->end > end) {
 885		if (state->state & exclusive_bits) {
 886			*failed_start = start;
 887			err = -EEXIST;
 888			goto out;
 889		}
 890
 891		prealloc = alloc_extent_state_atomic(prealloc);
 892		BUG_ON(!prealloc);
 893		err = split_state(tree, state, prealloc, end + 1);
 894		if (err)
 895			extent_io_tree_panic(tree, err);
 896
 897		set_state_bits(tree, prealloc, &bits);
 898		cache_state(prealloc, cached_state);
 899		merge_state(tree, prealloc);
 900		prealloc = NULL;
 901		goto out;
 902	}
 903
 904	goto search_again;
 905
 906out:
 907	spin_unlock(&tree->lock);
 908	if (prealloc)
 909		free_extent_state(prealloc);
 910
 911	return err;
 912
 913search_again:
 914	if (start > end)
 915		goto out;
 916	spin_unlock(&tree->lock);
 917	if (mask & __GFP_WAIT)
 918		cond_resched();
 919	goto again;
 920}
 921
 922int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits,
 923		   u64 *failed_start, struct extent_state **cached_state,
 924		   gfp_t mask)
 925{
 926	return __set_extent_bit(tree, start, end, bits, 0, failed_start,
 927				cached_state, mask);
 928}
 929
 930
 931/**
 932 * convert_extent - convert all bits in a given range from one bit to another
 
 933 * @tree:	the io tree to search
 934 * @start:	the start offset in bytes
 935 * @end:	the end offset in bytes (inclusive)
 936 * @bits:	the bits to set in this range
 937 * @clear_bits:	the bits to clear in this range
 
 938 * @mask:	the allocation mask
 939 *
 940 * This will go through and set bits for the given range.  If any states exist
 941 * already in this range they are set with the given bit and cleared of the
 942 * clear_bits.  This is only meant to be used by things that are mergeable, ie
 943 * converting from say DELALLOC to DIRTY.  This is not meant to be used with
 944 * boundary bits like LOCK.
 945 */
 946int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 947		       int bits, int clear_bits, gfp_t mask)
 
 948{
 949	struct extent_state *state;
 950	struct extent_state *prealloc = NULL;
 951	struct rb_node *node;
 
 
 952	int err = 0;
 953	u64 last_start;
 954	u64 last_end;
 
 
 
 955
 956again:
 957	if (!prealloc && (mask & __GFP_WAIT)) {
 
 
 
 
 
 
 
 958		prealloc = alloc_extent_state(mask);
 959		if (!prealloc)
 960			return -ENOMEM;
 961	}
 962
 963	spin_lock(&tree->lock);
 
 
 
 
 
 
 
 
 
 964	/*
 965	 * this search will find all the extents that end after
 966	 * our range starts.
 967	 */
 968	node = tree_search(tree, start);
 969	if (!node) {
 970		prealloc = alloc_extent_state_atomic(prealloc);
 971		if (!prealloc) {
 972			err = -ENOMEM;
 973			goto out;
 974		}
 975		err = insert_state(tree, prealloc, start, end, &bits);
 976		prealloc = NULL;
 977		if (err)
 978			extent_io_tree_panic(tree, err);
 
 
 979		goto out;
 980	}
 981	state = rb_entry(node, struct extent_state, rb_node);
 982hit_next:
 983	last_start = state->start;
 984	last_end = state->end;
 985
 986	/*
 987	 * | ---- desired range ---- |
 988	 * | state |
 989	 *
 990	 * Just lock what we found and keep going
 991	 */
 992	if (state->start == start && state->end <= end) {
 993		set_state_bits(tree, state, &bits);
 994		state = clear_state_bit(tree, state, &clear_bits, 0);
 
 995		if (last_end == (u64)-1)
 996			goto out;
 997		start = last_end + 1;
 998		if (start < end && state && state->start == start &&
 999		    !need_resched())
1000			goto hit_next;
1001		goto search_again;
1002	}
1003
1004	/*
1005	 *     | ---- desired range ---- |
1006	 * | state |
1007	 *   or
1008	 * | ------------- state -------------- |
1009	 *
1010	 * We need to split the extent we found, and may flip bits on
1011	 * second half.
1012	 *
1013	 * If the extent we found extends past our
1014	 * range, we just split and search again.  It'll get split
1015	 * again the next time though.
1016	 *
1017	 * If the extent we found is inside our range, we set the
1018	 * desired bit on it.
1019	 */
1020	if (state->start < start) {
1021		prealloc = alloc_extent_state_atomic(prealloc);
1022		if (!prealloc) {
1023			err = -ENOMEM;
1024			goto out;
1025		}
1026		err = split_state(tree, state, prealloc, start);
1027		if (err)
1028			extent_io_tree_panic(tree, err);
1029		prealloc = NULL;
1030		if (err)
1031			goto out;
1032		if (state->end <= end) {
1033			set_state_bits(tree, state, &bits);
1034			state = clear_state_bit(tree, state, &clear_bits, 0);
 
 
1035			if (last_end == (u64)-1)
1036				goto out;
1037			start = last_end + 1;
1038			if (start < end && state && state->start == start &&
1039			    !need_resched())
1040				goto hit_next;
1041		}
1042		goto search_again;
1043	}
1044	/*
1045	 * | ---- desired range ---- |
1046	 *     | state | or               | state |
1047	 *
1048	 * There's a hole, we need to insert something in it and
1049	 * ignore the extent we found.
1050	 */
1051	if (state->start > start) {
1052		u64 this_end;
1053		if (end < last_start)
1054			this_end = end;
1055		else
1056			this_end = last_start - 1;
1057
1058		prealloc = alloc_extent_state_atomic(prealloc);
1059		if (!prealloc) {
1060			err = -ENOMEM;
1061			goto out;
1062		}
1063
1064		/*
1065		 * Avoid to free 'prealloc' if it can be merged with
1066		 * the later extent.
1067		 */
1068		err = insert_state(tree, prealloc, start, this_end,
1069				   &bits);
1070		if (err)
1071			extent_io_tree_panic(tree, err);
 
1072		prealloc = NULL;
1073		start = this_end + 1;
1074		goto search_again;
1075	}
1076	/*
1077	 * | ---- desired range ---- |
1078	 *                        | state |
1079	 * We need to split the extent, and set the bit
1080	 * on the first half
1081	 */
1082	if (state->start <= end && state->end > end) {
1083		prealloc = alloc_extent_state_atomic(prealloc);
1084		if (!prealloc) {
1085			err = -ENOMEM;
1086			goto out;
1087		}
1088
1089		err = split_state(tree, state, prealloc, end + 1);
1090		if (err)
1091			extent_io_tree_panic(tree, err);
1092
1093		set_state_bits(tree, prealloc, &bits);
1094		clear_state_bit(tree, prealloc, &clear_bits, 0);
 
1095		prealloc = NULL;
1096		goto out;
1097	}
1098
1099	goto search_again;
1100
1101out:
1102	spin_unlock(&tree->lock);
1103	if (prealloc)
1104		free_extent_state(prealloc);
1105
1106	return err;
1107
1108search_again:
1109	if (start > end)
1110		goto out;
1111	spin_unlock(&tree->lock);
1112	if (mask & __GFP_WAIT)
1113		cond_resched();
 
1114	goto again;
1115}
1116
1117/* wrappers around set/clear extent bit */
1118int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
1119		     gfp_t mask)
1120{
1121	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
1122			      NULL, mask);
1123}
1124
1125int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1126		    int bits, gfp_t mask)
1127{
1128	return set_extent_bit(tree, start, end, bits, NULL,
1129			      NULL, mask);
1130}
1131
1132int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1133		      int bits, gfp_t mask)
1134{
1135	return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
1136}
1137
1138int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
1139			struct extent_state **cached_state, gfp_t mask)
1140{
1141	return set_extent_bit(tree, start, end,
1142			      EXTENT_DELALLOC | EXTENT_UPTODATE,
1143			      NULL, cached_state, mask);
1144}
1145
1146int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
1147		       gfp_t mask)
1148{
1149	return clear_extent_bit(tree, start, end,
1150				EXTENT_DIRTY | EXTENT_DELALLOC |
1151				EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
1152}
1153
1154int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
1155		     gfp_t mask)
1156{
1157	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL,
1158			      NULL, mask);
1159}
1160
1161int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1162			struct extent_state **cached_state, gfp_t mask)
 
1163{
1164	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
1165			      cached_state, mask);
1166}
 
 
1167
1168int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1169			  struct extent_state **cached_state, gfp_t mask)
1170{
1171	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
1172				cached_state, mask);
1173}
1174
1175/*
1176 * either insert or lock state struct between start and end use mask to tell
1177 * us if waiting is desired.
1178 */
1179int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1180		     int bits, struct extent_state **cached_state)
1181{
1182	int err;
1183	u64 failed_start;
 
1184	while (1) {
1185		err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
1186				       EXTENT_LOCKED, &failed_start,
1187				       cached_state, GFP_NOFS);
1188		if (err == -EEXIST) {
1189			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1190			start = failed_start;
1191		} else
1192			break;
1193		WARN_ON(start > end);
1194	}
1195	return err;
1196}
1197
1198int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1199{
1200	return lock_extent_bits(tree, start, end, 0, NULL);
1201}
1202
1203int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1204{
1205	int err;
1206	u64 failed_start;
1207
1208	err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1209			       &failed_start, NULL, GFP_NOFS);
1210	if (err == -EEXIST) {
1211		if (failed_start > start)
1212			clear_extent_bit(tree, start, failed_start - 1,
1213					 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1214		return 0;
1215	}
1216	return 1;
1217}
1218
1219int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1220			 struct extent_state **cached, gfp_t mask)
1221{
1222	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1223				mask);
 
 
 
 
 
 
 
 
 
1224}
1225
1226int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1227{
1228	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1229				GFP_NOFS);
 
 
 
 
 
 
 
 
 
 
1230}
1231
1232/*
1233 * helper function to set both pages and extents in the tree writeback
1234 */
1235static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1236{
1237	unsigned long index = start >> PAGE_CACHE_SHIFT;
1238	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1239	struct page *page;
1240
1241	while (index <= end_index) {
1242		page = find_get_page(tree->mapping, index);
1243		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1244		set_page_writeback(page);
1245		page_cache_release(page);
1246		index++;
1247	}
1248	return 0;
1249}
1250
1251/* find the first state struct with 'bits' set after 'start', and
1252 * return it.  tree->lock must be held.  NULL will returned if
1253 * nothing was found after 'start'
1254 */
1255struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1256						 u64 start, int bits)
 
1257{
1258	struct rb_node *node;
1259	struct extent_state *state;
1260
1261	/*
1262	 * this search will find all the extents that end after
1263	 * our range starts.
1264	 */
1265	node = tree_search(tree, start);
1266	if (!node)
1267		goto out;
1268
1269	while (1) {
1270		state = rb_entry(node, struct extent_state, rb_node);
1271		if (state->end >= start && (state->state & bits))
1272			return state;
1273
1274		node = rb_next(node);
1275		if (!node)
1276			break;
1277	}
1278out:
1279	return NULL;
1280}
1281
1282/*
1283 * find the first offset in the io tree with 'bits' set. zero is
1284 * returned if we find something, and *start_ret and *end_ret are
1285 * set to reflect the state struct that was found.
1286 *
1287 * If nothing was found, 1 is returned. If found something, return 0.
1288 */
1289int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1290			  u64 *start_ret, u64 *end_ret, int bits)
 
1291{
1292	struct extent_state *state;
 
1293	int ret = 1;
1294
1295	spin_lock(&tree->lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1296	state = find_first_extent_bit_state(tree, start, bits);
 
1297	if (state) {
 
1298		*start_ret = state->start;
1299		*end_ret = state->end;
1300		ret = 0;
1301	}
 
1302	spin_unlock(&tree->lock);
1303	return ret;
1304}
1305
1306/*
1307 * find a contiguous range of bytes in the file marked as delalloc, not
1308 * more than 'max_bytes'.  start and end are used to return the range,
1309 *
1310 * 1 is returned if we find something, 0 if nothing was in the tree
1311 */
1312static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1313					u64 *start, u64 *end, u64 max_bytes,
1314					struct extent_state **cached_state)
1315{
1316	struct rb_node *node;
1317	struct extent_state *state;
1318	u64 cur_start = *start;
1319	u64 found = 0;
1320	u64 total_bytes = 0;
1321
1322	spin_lock(&tree->lock);
1323
1324	/*
1325	 * this search will find all the extents that end after
1326	 * our range starts.
1327	 */
1328	node = tree_search(tree, cur_start);
1329	if (!node) {
1330		if (!found)
1331			*end = (u64)-1;
1332		goto out;
1333	}
1334
1335	while (1) {
1336		state = rb_entry(node, struct extent_state, rb_node);
1337		if (found && (state->start != cur_start ||
1338			      (state->state & EXTENT_BOUNDARY))) {
1339			goto out;
1340		}
1341		if (!(state->state & EXTENT_DELALLOC)) {
1342			if (!found)
1343				*end = state->end;
1344			goto out;
1345		}
1346		if (!found) {
1347			*start = state->start;
1348			*cached_state = state;
1349			atomic_inc(&state->refs);
1350		}
1351		found++;
1352		*end = state->end;
1353		cur_start = state->end + 1;
1354		node = rb_next(node);
1355		if (!node)
1356			break;
1357		total_bytes += state->end - state->start + 1;
1358		if (total_bytes >= max_bytes)
1359			break;
 
 
1360	}
1361out:
1362	spin_unlock(&tree->lock);
1363	return found;
1364}
1365
1366static noinline void __unlock_for_delalloc(struct inode *inode,
1367					   struct page *locked_page,
1368					   u64 start, u64 end)
1369{
1370	int ret;
1371	struct page *pages[16];
1372	unsigned long index = start >> PAGE_CACHE_SHIFT;
1373	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1374	unsigned long nr_pages = end_index - index + 1;
1375	int i;
1376
1377	if (index == locked_page->index && end_index == index)
1378		return;
1379
1380	while (nr_pages > 0) {
1381		ret = find_get_pages_contig(inode->i_mapping, index,
1382				     min_t(unsigned long, nr_pages,
1383				     ARRAY_SIZE(pages)), pages);
1384		for (i = 0; i < ret; i++) {
1385			if (pages[i] != locked_page)
1386				unlock_page(pages[i]);
1387			page_cache_release(pages[i]);
1388		}
1389		nr_pages -= ret;
1390		index += ret;
1391		cond_resched();
1392	}
1393}
1394
1395static noinline int lock_delalloc_pages(struct inode *inode,
1396					struct page *locked_page,
1397					u64 delalloc_start,
1398					u64 delalloc_end)
1399{
1400	unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1401	unsigned long start_index = index;
1402	unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1403	unsigned long pages_locked = 0;
1404	struct page *pages[16];
1405	unsigned long nrpages;
1406	int ret;
1407	int i;
1408
1409	/* the caller is responsible for locking the start index */
1410	if (index == locked_page->index && index == end_index)
1411		return 0;
1412
1413	/* skip the page at the start index */
1414	nrpages = end_index - index + 1;
1415	while (nrpages > 0) {
1416		ret = find_get_pages_contig(inode->i_mapping, index,
1417				     min_t(unsigned long,
1418				     nrpages, ARRAY_SIZE(pages)), pages);
1419		if (ret == 0) {
1420			ret = -EAGAIN;
1421			goto done;
1422		}
1423		/* now we have an array of pages, lock them all */
1424		for (i = 0; i < ret; i++) {
1425			/*
1426			 * the caller is taking responsibility for
1427			 * locked_page
1428			 */
1429			if (pages[i] != locked_page) {
1430				lock_page(pages[i]);
1431				if (!PageDirty(pages[i]) ||
1432				    pages[i]->mapping != inode->i_mapping) {
1433					ret = -EAGAIN;
1434					unlock_page(pages[i]);
1435					page_cache_release(pages[i]);
1436					goto done;
1437				}
1438			}
1439			page_cache_release(pages[i]);
1440			pages_locked++;
1441		}
1442		nrpages -= ret;
1443		index += ret;
1444		cond_resched();
1445	}
1446	ret = 0;
1447done:
1448	if (ret && pages_locked) {
1449		__unlock_for_delalloc(inode, locked_page,
1450			      delalloc_start,
1451			      ((u64)(start_index + pages_locked - 1)) <<
1452			      PAGE_CACHE_SHIFT);
1453	}
1454	return ret;
1455}
1456
1457/*
1458 * find a contiguous range of bytes in the file marked as delalloc, not
1459 * more than 'max_bytes'.  start and end are used to return the range,
1460 *
1461 * 1 is returned if we find something, 0 if nothing was in the tree
1462 */
1463static noinline u64 find_lock_delalloc_range(struct inode *inode,
1464					     struct extent_io_tree *tree,
1465					     struct page *locked_page,
1466					     u64 *start, u64 *end,
1467					     u64 max_bytes)
1468{
1469	u64 delalloc_start;
1470	u64 delalloc_end;
1471	u64 found;
1472	struct extent_state *cached_state = NULL;
1473	int ret;
1474	int loops = 0;
1475
1476again:
1477	/* step one, find a bunch of delalloc bytes starting at start */
1478	delalloc_start = *start;
1479	delalloc_end = 0;
1480	found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1481				    max_bytes, &cached_state);
1482	if (!found || delalloc_end <= *start) {
1483		*start = delalloc_start;
1484		*end = delalloc_end;
1485		free_extent_state(cached_state);
1486		return found;
1487	}
1488
1489	/*
1490	 * start comes from the offset of locked_page.  We have to lock
1491	 * pages in order, so we can't process delalloc bytes before
1492	 * locked_page
1493	 */
1494	if (delalloc_start < *start)
1495		delalloc_start = *start;
1496
1497	/*
1498	 * make sure to limit the number of pages we try to lock down
1499	 * if we're looping.
1500	 */
1501	if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1502		delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1503
1504	/* step two, lock all the pages after the page that has start */
1505	ret = lock_delalloc_pages(inode, locked_page,
1506				  delalloc_start, delalloc_end);
1507	if (ret == -EAGAIN) {
1508		/* some of the pages are gone, lets avoid looping by
1509		 * shortening the size of the delalloc range we're searching
1510		 */
1511		free_extent_state(cached_state);
 
1512		if (!loops) {
1513			unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1514			max_bytes = PAGE_CACHE_SIZE - offset;
1515			loops = 1;
1516			goto again;
1517		} else {
1518			found = 0;
1519			goto out_failed;
1520		}
1521	}
1522	BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1523
1524	/* step three, lock the state bits for the whole range */
1525	lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
1526
1527	/* then test to make sure it is all still delalloc */
1528	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1529			     EXTENT_DELALLOC, 1, cached_state);
1530	if (!ret) {
1531		unlock_extent_cached(tree, delalloc_start, delalloc_end,
1532				     &cached_state, GFP_NOFS);
1533		__unlock_for_delalloc(inode, locked_page,
1534			      delalloc_start, delalloc_end);
1535		cond_resched();
1536		goto again;
1537	}
1538	free_extent_state(cached_state);
1539	*start = delalloc_start;
1540	*end = delalloc_end;
1541out_failed:
1542	return found;
1543}
1544
1545int extent_clear_unlock_delalloc(struct inode *inode,
1546				struct extent_io_tree *tree,
1547				u64 start, u64 end, struct page *locked_page,
1548				unsigned long op)
1549{
 
1550	int ret;
1551	struct page *pages[16];
1552	unsigned long index = start >> PAGE_CACHE_SHIFT;
1553	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1554	unsigned long nr_pages = end_index - index + 1;
1555	int i;
1556	int clear_bits = 0;
1557
1558	if (op & EXTENT_CLEAR_UNLOCK)
1559		clear_bits |= EXTENT_LOCKED;
1560	if (op & EXTENT_CLEAR_DIRTY)
1561		clear_bits |= EXTENT_DIRTY;
1562
1563	if (op & EXTENT_CLEAR_DELALLOC)
1564		clear_bits |= EXTENT_DELALLOC;
1565
1566	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1567	if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1568		    EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1569		    EXTENT_SET_PRIVATE2)))
1570		return 0;
 
1571
1572	while (nr_pages > 0) {
1573		ret = find_get_pages_contig(inode->i_mapping, index,
1574				     min_t(unsigned long,
1575				     nr_pages, ARRAY_SIZE(pages)), pages);
1576		for (i = 0; i < ret; i++) {
1577
1578			if (op & EXTENT_SET_PRIVATE2)
1579				SetPagePrivate2(pages[i]);
1580
1581			if (pages[i] == locked_page) {
1582				page_cache_release(pages[i]);
1583				continue;
1584			}
1585			if (op & EXTENT_CLEAR_DIRTY)
1586				clear_page_dirty_for_io(pages[i]);
1587			if (op & EXTENT_SET_WRITEBACK)
1588				set_page_writeback(pages[i]);
1589			if (op & EXTENT_END_WRITEBACK)
 
 
1590				end_page_writeback(pages[i]);
1591			if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1592				unlock_page(pages[i]);
1593			page_cache_release(pages[i]);
1594		}
1595		nr_pages -= ret;
1596		index += ret;
1597		cond_resched();
1598	}
1599	return 0;
1600}
1601
1602/*
1603 * count the number of bytes in the tree that have a given bit(s)
1604 * set.  This can be fairly slow, except for EXTENT_DIRTY which is
1605 * cached.  The total number found is returned.
1606 */
1607u64 count_range_bits(struct extent_io_tree *tree,
1608		     u64 *start, u64 search_end, u64 max_bytes,
1609		     unsigned long bits, int contig)
1610{
1611	struct rb_node *node;
1612	struct extent_state *state;
1613	u64 cur_start = *start;
1614	u64 total_bytes = 0;
1615	u64 last = 0;
1616	int found = 0;
1617
1618	if (search_end <= cur_start) {
1619		WARN_ON(1);
1620		return 0;
1621	}
1622
1623	spin_lock(&tree->lock);
1624	if (cur_start == 0 && bits == EXTENT_DIRTY) {
1625		total_bytes = tree->dirty_bytes;
1626		goto out;
1627	}
1628	/*
1629	 * this search will find all the extents that end after
1630	 * our range starts.
1631	 */
1632	node = tree_search(tree, cur_start);
1633	if (!node)
1634		goto out;
1635
1636	while (1) {
1637		state = rb_entry(node, struct extent_state, rb_node);
1638		if (state->start > search_end)
1639			break;
1640		if (contig && found && state->start > last + 1)
1641			break;
1642		if (state->end >= cur_start && (state->state & bits) == bits) {
1643			total_bytes += min(search_end, state->end) + 1 -
1644				       max(cur_start, state->start);
1645			if (total_bytes >= max_bytes)
1646				break;
1647			if (!found) {
1648				*start = max(cur_start, state->start);
1649				found = 1;
1650			}
1651			last = state->end;
1652		} else if (contig && found) {
1653			break;
1654		}
1655		node = rb_next(node);
1656		if (!node)
1657			break;
1658	}
1659out:
1660	spin_unlock(&tree->lock);
1661	return total_bytes;
1662}
1663
1664/*
1665 * set the private field for a given byte offset in the tree.  If there isn't
1666 * an extent_state there already, this does nothing.
1667 */
1668int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
 
1669{
1670	struct rb_node *node;
1671	struct extent_state *state;
1672	int ret = 0;
1673
1674	spin_lock(&tree->lock);
1675	/*
1676	 * this search will find all the extents that end after
1677	 * our range starts.
1678	 */
1679	node = tree_search(tree, start);
1680	if (!node) {
1681		ret = -ENOENT;
1682		goto out;
1683	}
1684	state = rb_entry(node, struct extent_state, rb_node);
1685	if (state->start != start) {
1686		ret = -ENOENT;
1687		goto out;
1688	}
1689	state->private = private;
1690out:
1691	spin_unlock(&tree->lock);
1692	return ret;
1693}
1694
1695int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
 
1696{
1697	struct rb_node *node;
1698	struct extent_state *state;
1699	int ret = 0;
1700
1701	spin_lock(&tree->lock);
1702	/*
1703	 * this search will find all the extents that end after
1704	 * our range starts.
1705	 */
1706	node = tree_search(tree, start);
1707	if (!node) {
1708		ret = -ENOENT;
1709		goto out;
1710	}
1711	state = rb_entry(node, struct extent_state, rb_node);
1712	if (state->start != start) {
1713		ret = -ENOENT;
1714		goto out;
1715	}
1716	*private = state->private;
1717out:
1718	spin_unlock(&tree->lock);
1719	return ret;
1720}
1721
1722/*
1723 * searches a range in the state tree for a given mask.
1724 * If 'filled' == 1, this returns 1 only if every extent in the tree
1725 * has the bits set.  Otherwise, 1 is returned if any bit in the
1726 * range is found set.
1727 */
1728int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1729		   int bits, int filled, struct extent_state *cached)
1730{
1731	struct extent_state *state = NULL;
1732	struct rb_node *node;
1733	int bitset = 0;
1734
1735	spin_lock(&tree->lock);
1736	if (cached && cached->tree && cached->start <= start &&
1737	    cached->end > start)
1738		node = &cached->rb_node;
1739	else
1740		node = tree_search(tree, start);
1741	while (node && start <= end) {
1742		state = rb_entry(node, struct extent_state, rb_node);
1743
1744		if (filled && state->start > start) {
1745			bitset = 0;
1746			break;
1747		}
1748
1749		if (state->start > end)
1750			break;
1751
1752		if (state->state & bits) {
1753			bitset = 1;
1754			if (!filled)
1755				break;
1756		} else if (filled) {
1757			bitset = 0;
1758			break;
1759		}
1760
1761		if (state->end == (u64)-1)
1762			break;
1763
1764		start = state->end + 1;
1765		if (start > end)
1766			break;
1767		node = rb_next(node);
1768		if (!node) {
1769			if (filled)
1770				bitset = 0;
1771			break;
1772		}
1773	}
1774	spin_unlock(&tree->lock);
1775	return bitset;
1776}
1777
1778/*
1779 * helper function to set a given page up to date if all the
1780 * extents in the tree for that page are up to date
1781 */
1782static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1783{
1784	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1785	u64 end = start + PAGE_CACHE_SIZE - 1;
1786	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1787		SetPageUptodate(page);
1788}
1789
1790/*
1791 * helper function to unlock a page if all the extents in the tree
1792 * for that page are unlocked
1793 */
1794static void check_page_locked(struct extent_io_tree *tree, struct page *page)
1795{
1796	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1797	u64 end = start + PAGE_CACHE_SIZE - 1;
1798	if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1799		unlock_page(page);
1800}
1801
1802/*
1803 * helper function to end page writeback if all the extents
1804 * in the tree for that page are done with writeback
1805 */
1806static void check_page_writeback(struct extent_io_tree *tree,
1807				 struct page *page)
1808{
1809	end_page_writeback(page);
1810}
1811
1812/*
1813 * When IO fails, either with EIO or csum verification fails, we
1814 * try other mirrors that might have a good copy of the data.  This
1815 * io_failure_record is used to record state as we go through all the
1816 * mirrors.  If another mirror has good data, the page is set up to date
1817 * and things continue.  If a good mirror can't be found, the original
1818 * bio end_io callback is called to indicate things have failed.
1819 */
1820struct io_failure_record {
1821	struct page *page;
1822	u64 start;
1823	u64 len;
1824	u64 logical;
1825	unsigned long bio_flags;
1826	int this_mirror;
1827	int failed_mirror;
1828	int in_validation;
1829};
1830
1831static int free_io_failure(struct inode *inode, struct io_failure_record *rec,
1832				int did_repair)
1833{
1834	int ret;
1835	int err = 0;
1836	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1837
1838	set_state_private(failure_tree, rec->start, 0);
1839	ret = clear_extent_bits(failure_tree, rec->start,
1840				rec->start + rec->len - 1,
1841				EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1842	if (ret)
1843		err = ret;
1844
1845	if (did_repair) {
1846		ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
1847					rec->start + rec->len - 1,
1848					EXTENT_DAMAGED, GFP_NOFS);
1849		if (ret && !err)
1850			err = ret;
1851	}
1852
1853	kfree(rec);
1854	return err;
1855}
1856
1857static void repair_io_failure_callback(struct bio *bio, int err)
1858{
1859	complete(bio->bi_private);
1860}
1861
1862/*
1863 * this bypasses the standard btrfs submit functions deliberately, as
1864 * the standard behavior is to write all copies in a raid setup. here we only
1865 * want to write the one bad copy. so we do the mapping for ourselves and issue
1866 * submit_bio directly.
1867 * to avoid any synchonization issues, wait for the data after writing, which
1868 * actually prevents the read that triggered the error from finishing.
1869 * currently, there can be no more than two copies of every data bit. thus,
1870 * exactly one rewrite is required.
1871 */
1872int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start,
1873			u64 length, u64 logical, struct page *page,
1874			int mirror_num)
1875{
 
1876	struct bio *bio;
1877	struct btrfs_device *dev;
1878	DECLARE_COMPLETION_ONSTACK(compl);
1879	u64 map_length = 0;
1880	u64 sector;
1881	struct btrfs_bio *bbio = NULL;
 
1882	int ret;
1883
 
1884	BUG_ON(!mirror_num);
1885
1886	bio = bio_alloc(GFP_NOFS, 1);
 
 
 
 
1887	if (!bio)
1888		return -EIO;
1889	bio->bi_private = &compl;
1890	bio->bi_end_io = repair_io_failure_callback;
1891	bio->bi_size = 0;
1892	map_length = length;
1893
1894	ret = btrfs_map_block(map_tree, WRITE, logical,
1895			      &map_length, &bbio, mirror_num);
1896	if (ret) {
1897		bio_put(bio);
1898		return -EIO;
1899	}
1900	BUG_ON(mirror_num != bbio->mirror_num);
1901	sector = bbio->stripes[mirror_num-1].physical >> 9;
1902	bio->bi_sector = sector;
1903	dev = bbio->stripes[mirror_num-1].dev;
1904	kfree(bbio);
1905	if (!dev || !dev->bdev || !dev->writeable) {
1906		bio_put(bio);
1907		return -EIO;
1908	}
1909	bio->bi_bdev = dev->bdev;
1910	bio_add_page(bio, page, length, start-page_offset(page));
1911	btrfsic_submit_bio(WRITE_SYNC, bio);
1912	wait_for_completion(&compl);
1913
1914	if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1915		/* try to remap that extent elsewhere? */
1916		bio_put(bio);
1917		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
1918		return -EIO;
1919	}
1920
1921	printk_in_rcu(KERN_INFO "btrfs read error corrected: ino %lu off %llu "
1922		      "(dev %s sector %llu)\n", page->mapping->host->i_ino,
1923		      start, rcu_str_deref(dev->name), sector);
1924
1925	bio_put(bio);
1926	return 0;
1927}
1928
1929int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
1930			 int mirror_num)
1931{
1932	struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1933	u64 start = eb->start;
1934	unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
1935	int ret = 0;
1936
 
 
 
1937	for (i = 0; i < num_pages; i++) {
1938		struct page *p = extent_buffer_page(eb, i);
1939		ret = repair_io_failure(map_tree, start, PAGE_CACHE_SIZE,
1940					start, p, mirror_num);
 
 
1941		if (ret)
1942			break;
1943		start += PAGE_CACHE_SIZE;
1944	}
1945
1946	return ret;
1947}
1948
1949/*
1950 * each time an IO finishes, we do a fast check in the IO failure tree
1951 * to see if we need to process or clean up an io_failure_record
1952 */
1953static int clean_io_failure(u64 start, struct page *page)
 
1954{
1955	u64 private;
1956	u64 private_failure;
1957	struct io_failure_record *failrec;
1958	struct btrfs_mapping_tree *map_tree;
1959	struct extent_state *state;
1960	int num_copies;
1961	int did_repair = 0;
1962	int ret;
1963	struct inode *inode = page->mapping->host;
1964
1965	private = 0;
1966	ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1967				(u64)-1, 1, EXTENT_DIRTY, 0);
1968	if (!ret)
1969		return 0;
1970
1971	ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start,
1972				&private_failure);
1973	if (ret)
1974		return 0;
1975
1976	failrec = (struct io_failure_record *)(unsigned long) private_failure;
1977	BUG_ON(!failrec->this_mirror);
1978
1979	if (failrec->in_validation) {
1980		/* there was no real error, just free the record */
1981		pr_debug("clean_io_failure: freeing dummy error at %llu\n",
1982			 failrec->start);
1983		did_repair = 1;
1984		goto out;
1985	}
 
 
1986
1987	spin_lock(&BTRFS_I(inode)->io_tree.lock);
1988	state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1989					    failrec->start,
1990					    EXTENT_LOCKED);
1991	spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1992
1993	if (state && state->start == failrec->start) {
1994		map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
1995		num_copies = btrfs_num_copies(map_tree, failrec->logical,
1996						failrec->len);
1997		if (num_copies > 1)  {
1998			ret = repair_io_failure(map_tree, start, failrec->len,
1999						failrec->logical, page,
2000						failrec->failed_mirror);
2001			did_repair = !ret;
2002		}
2003	}
2004
2005out:
2006	if (!ret)
2007		ret = free_io_failure(inode, failrec, did_repair);
2008
2009	return ret;
2010}
2011
2012/*
2013 * this is a generic handler for readpage errors (default
2014 * readpage_io_failed_hook). if other copies exist, read those and write back
2015 * good data to the failed position. does not investigate in remapping the
2016 * failed extent elsewhere, hoping the device will be smart enough to do this as
2017 * needed
2018 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2019
2020static int bio_readpage_error(struct bio *failed_bio, struct page *page,
2021				u64 start, u64 end, int failed_mirror,
2022				struct extent_state *state)
2023{
2024	struct io_failure_record *failrec = NULL;
2025	u64 private;
2026	struct extent_map *em;
2027	struct inode *inode = page->mapping->host;
2028	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2029	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2030	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2031	struct bio *bio;
2032	int num_copies;
2033	int ret;
2034	int read_mode;
2035	u64 logical;
2036
2037	BUG_ON(failed_bio->bi_rw & REQ_WRITE);
2038
2039	ret = get_state_private(failure_tree, start, &private);
2040	if (ret) {
2041		failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2042		if (!failrec)
2043			return -ENOMEM;
 
2044		failrec->start = start;
2045		failrec->len = end - start + 1;
2046		failrec->this_mirror = 0;
2047		failrec->bio_flags = 0;
2048		failrec->in_validation = 0;
2049
2050		read_lock(&em_tree->lock);
2051		em = lookup_extent_mapping(em_tree, start, failrec->len);
2052		if (!em) {
2053			read_unlock(&em_tree->lock);
2054			kfree(failrec);
2055			return -EIO;
2056		}
2057
2058		if (em->start > start || em->start + em->len < start) {
2059			free_extent_map(em);
2060			em = NULL;
2061		}
2062		read_unlock(&em_tree->lock);
2063
2064		if (!em || IS_ERR(em)) {
2065			kfree(failrec);
2066			return -EIO;
2067		}
 
2068		logical = start - em->start;
2069		logical = em->block_start + logical;
2070		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2071			logical = em->block_start;
2072			failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2073			extent_set_compress_type(&failrec->bio_flags,
2074						 em->compress_type);
2075		}
2076		pr_debug("bio_readpage_error: (new) logical=%llu, start=%llu, "
2077			 "len=%llu\n", logical, start, failrec->len);
 
 
2078		failrec->logical = logical;
2079		free_extent_map(em);
2080
2081		/* set the bits in the private failure tree */
2082		ret = set_extent_bits(failure_tree, start, end,
2083					EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
2084		if (ret >= 0)
2085			ret = set_state_private(failure_tree, start,
2086						(u64)(unsigned long)failrec);
2087		/* set the bits in the inode's tree */
2088		if (ret >= 0)
2089			ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
2090						GFP_NOFS);
2091		if (ret < 0) {
2092			kfree(failrec);
2093			return ret;
2094		}
2095	} else {
2096		failrec = (struct io_failure_record *)(unsigned long)private;
2097		pr_debug("bio_readpage_error: (found) logical=%llu, "
2098			 "start=%llu, len=%llu, validation=%d\n",
2099			 failrec->logical, failrec->start, failrec->len,
2100			 failrec->in_validation);
2101		/*
2102		 * when data can be on disk more than twice, add to failrec here
2103		 * (e.g. with a list for failed_mirror) to make
2104		 * clean_io_failure() clean all those errors at once.
2105		 */
2106	}
2107	num_copies = btrfs_num_copies(
2108			      &BTRFS_I(inode)->root->fs_info->mapping_tree,
2109			      failrec->logical, failrec->len);
 
 
 
 
 
 
 
 
 
 
2110	if (num_copies == 1) {
2111		/*
2112		 * we only have a single copy of the data, so don't bother with
2113		 * all the retry and error correction code that follows. no
2114		 * matter what the error is, it is very likely to persist.
2115		 */
2116		pr_debug("bio_readpage_error: cannot repair, num_copies == 1. "
2117			 "state=%p, num_copies=%d, next_mirror %d, "
2118			 "failed_mirror %d\n", state, num_copies,
2119			 failrec->this_mirror, failed_mirror);
2120		free_io_failure(inode, failrec, 0);
2121		return -EIO;
2122	}
2123
2124	if (!state) {
2125		spin_lock(&tree->lock);
2126		state = find_first_extent_bit_state(tree, failrec->start,
2127						    EXTENT_LOCKED);
2128		if (state && state->start != failrec->start)
2129			state = NULL;
2130		spin_unlock(&tree->lock);
2131	}
2132
2133	/*
2134	 * there are two premises:
2135	 *	a) deliver good data to the caller
2136	 *	b) correct the bad sectors on disk
2137	 */
2138	if (failed_bio->bi_vcnt > 1) {
2139		/*
2140		 * to fulfill b), we need to know the exact failing sectors, as
2141		 * we don't want to rewrite any more than the failed ones. thus,
2142		 * we need separate read requests for the failed bio
2143		 *
2144		 * if the following BUG_ON triggers, our validation request got
2145		 * merged. we need separate requests for our algorithm to work.
2146		 */
2147		BUG_ON(failrec->in_validation);
2148		failrec->in_validation = 1;
2149		failrec->this_mirror = failed_mirror;
2150		read_mode = READ_SYNC | REQ_FAILFAST_DEV;
2151	} else {
2152		/*
2153		 * we're ready to fulfill a) and b) alongside. get a good copy
2154		 * of the failed sector and if we succeed, we have setup
2155		 * everything for repair_io_failure to do the rest for us.
2156		 */
2157		if (failrec->in_validation) {
2158			BUG_ON(failrec->this_mirror != failed_mirror);
2159			failrec->in_validation = 0;
2160			failrec->this_mirror = 0;
2161		}
2162		failrec->failed_mirror = failed_mirror;
2163		failrec->this_mirror++;
2164		if (failrec->this_mirror == failed_mirror)
2165			failrec->this_mirror++;
2166		read_mode = READ_SYNC;
2167	}
2168
2169	if (!state || failrec->this_mirror > num_copies) {
2170		pr_debug("bio_readpage_error: (fail) state=%p, num_copies=%d, "
2171			 "next_mirror %d, failed_mirror %d\n", state,
2172			 num_copies, failrec->this_mirror, failed_mirror);
2173		free_io_failure(inode, failrec, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2174		return -EIO;
2175	}
2176
2177	bio = bio_alloc(GFP_NOFS, 1);
 
 
 
 
 
 
 
 
 
2178	if (!bio) {
2179		free_io_failure(inode, failrec, 0);
2180		return -EIO;
2181	}
2182	bio->bi_private = state;
2183	bio->bi_end_io = failed_bio->bi_end_io;
2184	bio->bi_sector = failrec->logical >> 9;
2185	bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2186	bio->bi_size = 0;
2187
2188	bio_add_page(bio, page, failrec->len, start - page_offset(page));
2189
2190	pr_debug("bio_readpage_error: submitting new read[%#x] to "
2191		 "this_mirror=%d, num_copies=%d, in_validation=%d\n", read_mode,
2192		 failrec->this_mirror, num_copies, failrec->in_validation);
2193
2194	ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
2195					 failrec->this_mirror,
2196					 failrec->bio_flags, 0);
 
 
 
 
 
2197	return ret;
2198}
2199
2200/* lots and lots of room for performance fixes in the end_bio funcs */
2201
2202int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2203{
2204	int uptodate = (err == 0);
2205	struct extent_io_tree *tree;
2206	int ret;
2207
2208	tree = &BTRFS_I(page->mapping->host)->io_tree;
2209
2210	if (tree->ops && tree->ops->writepage_end_io_hook) {
2211		ret = tree->ops->writepage_end_io_hook(page, start,
2212					       end, NULL, uptodate);
2213		if (ret)
2214			uptodate = 0;
2215	}
2216
2217	if (!uptodate) {
2218		ClearPageUptodate(page);
2219		SetPageError(page);
 
 
2220	}
2221	return 0;
2222}
2223
2224/*
2225 * after a writepage IO is done, we need to:
2226 * clear the uptodate bits on error
2227 * clear the writeback bits in the extent tree for this IO
2228 * end_page_writeback if the page has no more pending IO
2229 *
2230 * Scheduling is not allowed, so the extent state tree is expected
2231 * to have one and only one object corresponding to this IO.
2232 */
2233static void end_bio_extent_writepage(struct bio *bio, int err)
2234{
2235	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2236	struct extent_io_tree *tree;
2237	u64 start;
2238	u64 end;
2239	int whole_page;
2240
2241	do {
2242		struct page *page = bvec->bv_page;
2243		tree = &BTRFS_I(page->mapping->host)->io_tree;
2244
2245		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
2246			 bvec->bv_offset;
2247		end = start + bvec->bv_len - 1;
2248
2249		if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
2250			whole_page = 1;
2251		else
2252			whole_page = 0;
2253
2254		if (--bvec >= bio->bi_io_vec)
2255			prefetchw(&bvec->bv_page->flags);
 
 
 
 
 
2256
2257		if (end_extent_writepage(page, err, start, end))
2258			continue;
2259
2260		if (whole_page)
2261			end_page_writeback(page);
2262		else
2263			check_page_writeback(tree, page);
2264	} while (bvec >= bio->bi_io_vec);
2265
2266	bio_put(bio);
2267}
2268
 
 
 
 
 
 
 
 
 
 
 
 
2269/*
2270 * after a readpage IO is done, we need to:
2271 * clear the uptodate bits on error
2272 * set the uptodate bits if things worked
2273 * set the page up to date if all extents in the tree are uptodate
2274 * clear the lock bit in the extent tree
2275 * unlock the page if there are no other extents locked for it
2276 *
2277 * Scheduling is not allowed, so the extent state tree is expected
2278 * to have one and only one object corresponding to this IO.
2279 */
2280static void end_bio_extent_readpage(struct bio *bio, int err)
2281{
2282	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
2283	struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
2284	struct bio_vec *bvec = bio->bi_io_vec;
2285	struct extent_io_tree *tree;
 
2286	u64 start;
2287	u64 end;
2288	int whole_page;
 
 
2289	int mirror;
2290	int ret;
 
2291
2292	if (err)
2293		uptodate = 0;
2294
2295	do {
2296		struct page *page = bvec->bv_page;
2297		struct extent_state *cached = NULL;
2298		struct extent_state *state;
2299
2300		pr_debug("end_bio_extent_readpage: bi_vcnt=%d, idx=%d, err=%d, "
2301			 "mirror=%ld\n", bio->bi_vcnt, bio->bi_idx, err,
2302			 (long int)bio->bi_bdev);
2303		tree = &BTRFS_I(page->mapping->host)->io_tree;
2304
2305		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
2306			bvec->bv_offset;
2307		end = start + bvec->bv_len - 1;
2308
2309		if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
2310			whole_page = 1;
2311		else
2312			whole_page = 0;
2313
2314		if (++bvec <= bvec_end)
2315			prefetchw(&bvec->bv_page->flags);
2316
2317		spin_lock(&tree->lock);
2318		state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
2319		if (state && state->start == start) {
2320			/*
2321			 * take a reference on the state, unlock will drop
2322			 * the ref
2323			 */
2324			cache_state(state, &cached);
2325		}
2326		spin_unlock(&tree->lock);
2327
2328		mirror = (int)(unsigned long)bio->bi_bdev;
2329		if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
2330			ret = tree->ops->readpage_end_io_hook(page, start, end,
2331							      state, mirror);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2332			if (ret)
2333				uptodate = 0;
2334			else
2335				clean_io_failure(start, page);
2336		}
2337
2338		if (!uptodate && tree->ops && tree->ops->readpage_io_failed_hook) {
 
 
 
2339			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2340			if (!ret && !err &&
2341			    test_bit(BIO_UPTODATE, &bio->bi_flags))
2342				uptodate = 1;
2343		} else if (!uptodate) {
2344			/*
2345			 * The generic bio_readpage_error handles errors the
2346			 * following way: If possible, new read requests are
2347			 * created and submitted and will end up in
2348			 * end_bio_extent_readpage as well (if we're lucky, not
2349			 * in the !uptodate case). In that case it returns 0 and
2350			 * we just go on with the next page in our bio. If it
2351			 * can't handle the error it will return -EIO and we
2352			 * remain responsible for that page.
2353			 */
2354			ret = bio_readpage_error(bio, page, start, end, mirror, NULL);
 
2355			if (ret == 0) {
2356				uptodate =
2357					test_bit(BIO_UPTODATE, &bio->bi_flags);
2358				if (err)
2359					uptodate = 0;
2360				uncache_state(&cached);
2361				continue;
2362			}
2363		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2364
2365		if (uptodate && tree->track_uptodate) {
2366			set_extent_uptodate(tree, start, end, &cached,
2367					    GFP_ATOMIC);
2368		}
2369		unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
2370
2371		if (whole_page) {
2372			if (uptodate) {
2373				SetPageUptodate(page);
2374			} else {
2375				ClearPageUptodate(page);
2376				SetPageError(page);
2377			}
2378			unlock_page(page);
 
 
 
 
 
 
2379		} else {
2380			if (uptodate) {
2381				check_page_uptodate(tree, page);
2382			} else {
2383				ClearPageUptodate(page);
2384				SetPageError(page);
2385			}
2386			check_page_locked(tree, page);
2387		}
2388	} while (bvec <= bvec_end);
2389
 
 
 
 
 
2390	bio_put(bio);
2391}
2392
 
 
 
 
2393struct bio *
2394btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
2395		gfp_t gfp_flags)
2396{
 
2397	struct bio *bio;
2398
2399	bio = bio_alloc(gfp_flags, nr_vecs);
2400
2401	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2402		while (!bio && (nr_vecs /= 2))
2403			bio = bio_alloc(gfp_flags, nr_vecs);
 
 
2404	}
2405
2406	if (bio) {
2407		bio->bi_size = 0;
2408		bio->bi_bdev = bdev;
2409		bio->bi_sector = first_sector;
 
 
 
 
2410	}
2411	return bio;
2412}
2413
2414/*
2415 * Since writes are async, they will only return -ENOMEM.
2416 * Reads can return the full range of I/O error conditions.
2417 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2418static int __must_check submit_one_bio(int rw, struct bio *bio,
2419				       int mirror_num, unsigned long bio_flags)
2420{
2421	int ret = 0;
2422	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2423	struct page *page = bvec->bv_page;
2424	struct extent_io_tree *tree = bio->bi_private;
2425	u64 start;
2426
2427	start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
2428
2429	bio->bi_private = NULL;
2430
2431	bio_get(bio);
2432
2433	if (tree->ops && tree->ops->submit_bio_hook)
2434		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2435					   mirror_num, bio_flags, start);
2436	else
2437		btrfsic_submit_bio(rw, bio);
2438
2439	if (bio_flagged(bio, BIO_EOPNOTSUPP))
2440		ret = -EOPNOTSUPP;
2441	bio_put(bio);
2442	return ret;
2443}
2444
2445static int merge_bio(struct extent_io_tree *tree, struct page *page,
2446		     unsigned long offset, size_t size, struct bio *bio,
2447		     unsigned long bio_flags)
2448{
2449	int ret = 0;
2450	if (tree->ops && tree->ops->merge_bio_hook)
2451		ret = tree->ops->merge_bio_hook(page, offset, size, bio,
2452						bio_flags);
2453	BUG_ON(ret < 0);
2454	return ret;
2455
2456}
2457
2458static int submit_extent_page(int rw, struct extent_io_tree *tree,
 
2459			      struct page *page, sector_t sector,
2460			      size_t size, unsigned long offset,
2461			      struct block_device *bdev,
2462			      struct bio **bio_ret,
2463			      unsigned long max_pages,
2464			      bio_end_io_t end_io_func,
2465			      int mirror_num,
2466			      unsigned long prev_bio_flags,
2467			      unsigned long bio_flags)
 
2468{
2469	int ret = 0;
2470	struct bio *bio;
2471	int nr;
2472	int contig = 0;
2473	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
2474	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2475	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2476
2477	if (bio_ret && *bio_ret) {
2478		bio = *bio_ret;
2479		if (old_compressed)
2480			contig = bio->bi_sector == sector;
2481		else
2482			contig = bio->bi_sector + (bio->bi_size >> 9) ==
2483				sector;
2484
2485		if (prev_bio_flags != bio_flags || !contig ||
2486		    merge_bio(tree, page, offset, page_size, bio, bio_flags) ||
 
2487		    bio_add_page(bio, page, page_size, offset) < page_size) {
2488			ret = submit_one_bio(rw, bio, mirror_num,
2489					     prev_bio_flags);
2490			if (ret < 0)
 
2491				return ret;
 
2492			bio = NULL;
2493		} else {
 
 
2494			return 0;
2495		}
2496	}
2497	if (this_compressed)
2498		nr = BIO_MAX_PAGES;
2499	else
2500		nr = bio_get_nr_vecs(bdev);
2501
2502	bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
 
2503	if (!bio)
2504		return -ENOMEM;
2505
2506	bio_add_page(bio, page, page_size, offset);
2507	bio->bi_end_io = end_io_func;
2508	bio->bi_private = tree;
 
 
 
 
2509
2510	if (bio_ret)
2511		*bio_ret = bio;
2512	else
2513		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2514
2515	return ret;
2516}
2517
2518void attach_extent_buffer_page(struct extent_buffer *eb, struct page *page)
 
2519{
2520	if (!PagePrivate(page)) {
2521		SetPagePrivate(page);
2522		page_cache_get(page);
2523		set_page_private(page, (unsigned long)eb);
2524	} else {
2525		WARN_ON(page->private != (unsigned long)eb);
2526	}
2527}
2528
2529void set_page_extent_mapped(struct page *page)
2530{
2531	if (!PagePrivate(page)) {
2532		SetPagePrivate(page);
2533		page_cache_get(page);
2534		set_page_private(page, EXTENT_PAGE_PRIVATE);
2535	}
2536}
2537
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2538/*
2539 * basic readpage implementation.  Locked extent state structs are inserted
2540 * into the tree that are removed when the IO is done (by the end_io
2541 * handlers)
2542 * XXX JDM: This needs looking at to ensure proper page locking
2543 */
2544static int __extent_read_full_page(struct extent_io_tree *tree,
2545				   struct page *page,
2546				   get_extent_t *get_extent,
2547				   struct bio **bio, int mirror_num,
2548				   unsigned long *bio_flags)
 
 
2549{
2550	struct inode *inode = page->mapping->host;
2551	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2552	u64 page_end = start + PAGE_CACHE_SIZE - 1;
2553	u64 end;
2554	u64 cur = start;
2555	u64 extent_offset;
2556	u64 last_byte = i_size_read(inode);
2557	u64 block_start;
2558	u64 cur_end;
2559	sector_t sector;
2560	struct extent_map *em;
2561	struct block_device *bdev;
2562	struct btrfs_ordered_extent *ordered;
2563	int ret;
2564	int nr = 0;
2565	size_t pg_offset = 0;
2566	size_t iosize;
2567	size_t disk_io_size;
2568	size_t blocksize = inode->i_sb->s_blocksize;
2569	unsigned long this_bio_flag = 0;
2570
2571	set_page_extent_mapped(page);
2572
 
2573	if (!PageUptodate(page)) {
2574		if (cleancache_get_page(page) == 0) {
2575			BUG_ON(blocksize != PAGE_SIZE);
 
2576			goto out;
2577		}
2578	}
2579
2580	end = page_end;
2581	while (1) {
2582		lock_extent(tree, start, end);
2583		ordered = btrfs_lookup_ordered_extent(inode, start);
2584		if (!ordered)
2585			break;
2586		unlock_extent(tree, start, end);
2587		btrfs_start_ordered_extent(inode, ordered, 1);
2588		btrfs_put_ordered_extent(ordered);
2589	}
2590
2591	if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
2592		char *userpage;
2593		size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
2594
2595		if (zero_offset) {
2596			iosize = PAGE_CACHE_SIZE - zero_offset;
2597			userpage = kmap_atomic(page);
2598			memset(userpage + zero_offset, 0, iosize);
2599			flush_dcache_page(page);
2600			kunmap_atomic(userpage);
2601		}
2602	}
2603	while (cur <= end) {
 
 
 
2604		if (cur >= last_byte) {
2605			char *userpage;
2606			struct extent_state *cached = NULL;
2607
2608			iosize = PAGE_CACHE_SIZE - pg_offset;
2609			userpage = kmap_atomic(page);
2610			memset(userpage + pg_offset, 0, iosize);
2611			flush_dcache_page(page);
2612			kunmap_atomic(userpage);
2613			set_extent_uptodate(tree, cur, cur + iosize - 1,
2614					    &cached, GFP_NOFS);
2615			unlock_extent_cached(tree, cur, cur + iosize - 1,
 
2616					     &cached, GFP_NOFS);
2617			break;
2618		}
2619		em = get_extent(inode, page, pg_offset, cur,
2620				end - cur + 1, 0);
2621		if (IS_ERR_OR_NULL(em)) {
2622			SetPageError(page);
2623			unlock_extent(tree, cur, end);
2624			break;
2625		}
2626		extent_offset = cur - em->start;
2627		BUG_ON(extent_map_end(em) <= cur);
2628		BUG_ON(end < cur);
2629
2630		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2631			this_bio_flag = EXTENT_BIO_COMPRESSED;
2632			extent_set_compress_type(&this_bio_flag,
2633						 em->compress_type);
2634		}
2635
2636		iosize = min(extent_map_end(em) - cur, end - cur + 1);
2637		cur_end = min(extent_map_end(em) - 1, end);
2638		iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2639		if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2640			disk_io_size = em->block_len;
2641			sector = em->block_start >> 9;
2642		} else {
2643			sector = (em->block_start + extent_offset) >> 9;
2644			disk_io_size = iosize;
2645		}
2646		bdev = em->bdev;
2647		block_start = em->block_start;
2648		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2649			block_start = EXTENT_MAP_HOLE;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2650		free_extent_map(em);
2651		em = NULL;
2652
2653		/* we've found a hole, just zero and go on */
2654		if (block_start == EXTENT_MAP_HOLE) {
2655			char *userpage;
2656			struct extent_state *cached = NULL;
2657
2658			userpage = kmap_atomic(page);
2659			memset(userpage + pg_offset, 0, iosize);
2660			flush_dcache_page(page);
2661			kunmap_atomic(userpage);
2662
2663			set_extent_uptodate(tree, cur, cur + iosize - 1,
2664					    &cached, GFP_NOFS);
2665			unlock_extent_cached(tree, cur, cur + iosize - 1,
2666			                     &cached, GFP_NOFS);
 
2667			cur = cur + iosize;
2668			pg_offset += iosize;
2669			continue;
2670		}
2671		/* the get_extent function already copied into the page */
2672		if (test_range_bit(tree, cur, cur_end,
2673				   EXTENT_UPTODATE, 1, NULL)) {
2674			check_page_uptodate(tree, page);
2675			unlock_extent(tree, cur, cur + iosize - 1);
2676			cur = cur + iosize;
2677			pg_offset += iosize;
2678			continue;
2679		}
2680		/* we have an inline extent but it didn't get marked up
2681		 * to date.  Error out
2682		 */
2683		if (block_start == EXTENT_MAP_INLINE) {
2684			SetPageError(page);
2685			unlock_extent(tree, cur, cur + iosize - 1);
2686			cur = cur + iosize;
2687			pg_offset += iosize;
2688			continue;
2689		}
2690
2691		ret = 0;
2692		if (tree->ops && tree->ops->readpage_io_hook) {
2693			ret = tree->ops->readpage_io_hook(page, cur,
2694							  cur + iosize - 1);
2695		}
2696		if (!ret) {
2697			unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2698			pnr -= page->index;
2699			ret = submit_extent_page(READ, tree, page,
2700					 sector, disk_io_size, pg_offset,
2701					 bdev, bio, pnr,
2702					 end_bio_extent_readpage, mirror_num,
2703					 *bio_flags,
2704					 this_bio_flag);
2705			BUG_ON(ret == -ENOMEM);
 
2706			nr++;
2707			*bio_flags = this_bio_flag;
2708		}
2709		if (ret)
2710			SetPageError(page);
 
 
2711		cur = cur + iosize;
2712		pg_offset += iosize;
2713	}
2714out:
2715	if (!nr) {
2716		if (!PageError(page))
2717			SetPageUptodate(page);
2718		unlock_page(page);
2719	}
2720	return 0;
2721}
2722
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2723int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2724			    get_extent_t *get_extent, int mirror_num)
2725{
2726	struct bio *bio = NULL;
2727	unsigned long bio_flags = 0;
2728	int ret;
2729
2730	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
2731				      &bio_flags);
2732	if (bio)
2733		ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
2734	return ret;
2735}
2736
2737static noinline void update_nr_written(struct page *page,
2738				      struct writeback_control *wbc,
2739				      unsigned long nr_written)
2740{
2741	wbc->nr_to_write -= nr_written;
2742	if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2743	    wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2744		page->mapping->writeback_index = page->index + nr_written;
2745}
2746
2747/*
2748 * the writepage semantics are similar to regular writepage.  extent
2749 * records are inserted to lock ranges in the tree, and as dirty areas
2750 * are found, they are marked writeback.  Then the lock bits are removed
2751 * and the end_io handler clears the writeback ranges
 
 
 
 
2752 */
2753static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2754			      void *data)
 
 
 
2755{
2756	struct inode *inode = page->mapping->host;
2757	struct extent_page_data *epd = data;
2758	struct extent_io_tree *tree = epd->tree;
2759	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2760	u64 delalloc_start;
2761	u64 page_end = start + PAGE_CACHE_SIZE - 1;
2762	u64 end;
2763	u64 cur = start;
2764	u64 extent_offset;
2765	u64 last_byte = i_size_read(inode);
2766	u64 block_start;
2767	u64 iosize;
2768	sector_t sector;
2769	struct extent_state *cached_state = NULL;
2770	struct extent_map *em;
2771	struct block_device *bdev;
2772	int ret;
2773	int nr = 0;
2774	size_t pg_offset = 0;
2775	size_t blocksize;
2776	loff_t i_size = i_size_read(inode);
2777	unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2778	u64 nr_delalloc;
2779	u64 delalloc_end;
2780	int page_started;
2781	int compressed;
2782	int write_flags;
2783	unsigned long nr_written = 0;
2784	bool fill_delalloc = true;
2785
2786	if (wbc->sync_mode == WB_SYNC_ALL)
2787		write_flags = WRITE_SYNC;
2788	else
2789		write_flags = WRITE;
2790
2791	trace___extent_writepage(page, inode, wbc);
2792
2793	WARN_ON(!PageLocked(page));
2794
2795	ClearPageError(page);
2796
2797	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2798	if (page->index > end_index ||
2799	   (page->index == end_index && !pg_offset)) {
2800		page->mapping->a_ops->invalidatepage(page, 0);
2801		unlock_page(page);
2802		return 0;
2803	}
2804
2805	if (page->index == end_index) {
2806		char *userpage;
2807
2808		userpage = kmap_atomic(page);
2809		memset(userpage + pg_offset, 0,
2810		       PAGE_CACHE_SIZE - pg_offset);
2811		kunmap_atomic(userpage);
2812		flush_dcache_page(page);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2813	}
2814	pg_offset = 0;
2815
2816	set_page_extent_mapped(page);
2817
2818	if (!tree->ops || !tree->ops->fill_delalloc)
2819		fill_delalloc = false;
 
 
 
2820
2821	delalloc_start = start;
2822	delalloc_end = 0;
2823	page_started = 0;
2824	if (!epd->extent_locked && fill_delalloc) {
2825		u64 delalloc_to_write = 0;
2826		/*
2827		 * make sure the wbc mapping index is at least updated
2828		 * to this page.
 
2829		 */
2830		update_nr_written(page, wbc, 0);
 
 
2831
2832		while (delalloc_end < page_end) {
2833			nr_delalloc = find_lock_delalloc_range(inode, tree,
2834						       page,
2835						       &delalloc_start,
2836						       &delalloc_end,
2837						       128 * 1024 * 1024);
2838			if (nr_delalloc == 0) {
2839				delalloc_start = delalloc_end + 1;
2840				continue;
2841			}
2842			ret = tree->ops->fill_delalloc(inode, page,
2843						       delalloc_start,
2844						       delalloc_end,
2845						       &page_started,
2846						       &nr_written);
2847			/* File system has been set read-only */
2848			if (ret) {
2849				SetPageError(page);
2850				goto done;
2851			}
2852			/*
2853			 * delalloc_end is already one less than the total
2854			 * length, so we don't subtract one from
2855			 * PAGE_CACHE_SIZE
2856			 */
2857			delalloc_to_write += (delalloc_end - delalloc_start +
2858					      PAGE_CACHE_SIZE) >>
2859					      PAGE_CACHE_SHIFT;
2860			delalloc_start = delalloc_end + 1;
2861		}
2862		if (wbc->nr_to_write < delalloc_to_write) {
2863			int thresh = 8192;
2864
2865			if (delalloc_to_write < thresh * 2)
2866				thresh = delalloc_to_write;
2867			wbc->nr_to_write = min_t(u64, delalloc_to_write,
2868						 thresh);
2869		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2870
2871		/* did the fill delalloc function already unlock and start
2872		 * the IO?
2873		 */
2874		if (page_started) {
2875			ret = 0;
2876			/*
2877			 * we've unlocked the page, so we can't update
2878			 * the mapping's writeback index, just update
2879			 * nr_to_write.
2880			 */
2881			wbc->nr_to_write -= nr_written;
2882			goto done_unlocked;
2883		}
2884	}
2885	if (tree->ops && tree->ops->writepage_start_hook) {
2886		ret = tree->ops->writepage_start_hook(page, start,
2887						      page_end);
2888		if (ret) {
2889			/* Fixup worker will requeue */
2890			if (ret == -EBUSY)
2891				wbc->pages_skipped++;
2892			else
2893				redirty_page_for_writepage(wbc, page);
 
2894			update_nr_written(page, wbc, nr_written);
2895			unlock_page(page);
2896			ret = 0;
2897			goto done_unlocked;
2898		}
2899	}
2900
2901	/*
2902	 * we don't want to touch the inode after unlocking the page,
2903	 * so we update the mapping writeback index now
2904	 */
2905	update_nr_written(page, wbc, nr_written + 1);
2906
2907	end = page_end;
2908	if (last_byte <= start) {
2909		if (tree->ops && tree->ops->writepage_end_io_hook)
2910			tree->ops->writepage_end_io_hook(page, start,
2911							 page_end, NULL, 1);
2912		goto done;
2913	}
2914
2915	blocksize = inode->i_sb->s_blocksize;
2916
2917	while (cur <= end) {
2918		if (cur >= last_byte) {
 
2919			if (tree->ops && tree->ops->writepage_end_io_hook)
2920				tree->ops->writepage_end_io_hook(page, cur,
2921							 page_end, NULL, 1);
2922			break;
2923		}
2924		em = epd->get_extent(inode, page, pg_offset, cur,
2925				     end - cur + 1, 1);
2926		if (IS_ERR_OR_NULL(em)) {
2927			SetPageError(page);
 
2928			break;
2929		}
2930
2931		extent_offset = cur - em->start;
2932		BUG_ON(extent_map_end(em) <= cur);
 
2933		BUG_ON(end < cur);
2934		iosize = min(extent_map_end(em) - cur, end - cur + 1);
2935		iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2936		sector = (em->block_start + extent_offset) >> 9;
2937		bdev = em->bdev;
2938		block_start = em->block_start;
2939		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2940		free_extent_map(em);
2941		em = NULL;
2942
2943		/*
2944		 * compressed and inline extents are written through other
2945		 * paths in the FS
2946		 */
2947		if (compressed || block_start == EXTENT_MAP_HOLE ||
2948		    block_start == EXTENT_MAP_INLINE) {
2949			/*
2950			 * end_io notification does not happen here for
2951			 * compressed extents
2952			 */
2953			if (!compressed && tree->ops &&
2954			    tree->ops->writepage_end_io_hook)
2955				tree->ops->writepage_end_io_hook(page, cur,
2956							 cur + iosize - 1,
2957							 NULL, 1);
2958			else if (compressed) {
2959				/* we don't want to end_page_writeback on
2960				 * a compressed extent.  this happens
2961				 * elsewhere
2962				 */
2963				nr++;
2964			}
2965
2966			cur += iosize;
2967			pg_offset += iosize;
2968			continue;
2969		}
2970		/* leave this out until we have a page_mkwrite call */
2971		if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2972				   EXTENT_DIRTY, 0, NULL)) {
2973			cur = cur + iosize;
2974			pg_offset += iosize;
2975			continue;
2976		}
2977
2978		if (tree->ops && tree->ops->writepage_io_hook) {
2979			ret = tree->ops->writepage_io_hook(page, cur,
2980						cur + iosize - 1);
2981		} else {
2982			ret = 0;
2983		}
2984		if (ret) {
2985			SetPageError(page);
2986		} else {
2987			unsigned long max_nr = end_index + 1;
2988
2989			set_range_writeback(tree, cur, cur + iosize - 1);
2990			if (!PageWriteback(page)) {
2991				printk(KERN_ERR "btrfs warning page %lu not "
2992				       "writeback, cur %llu end %llu\n",
2993				       page->index, (unsigned long long)cur,
2994				       (unsigned long long)end);
2995			}
2996
2997			ret = submit_extent_page(write_flags, tree, page,
2998						 sector, iosize, pg_offset,
2999						 bdev, &epd->bio, max_nr,
3000						 end_bio_extent_writepage,
3001						 0, 0, 0);
3002			if (ret)
3003				SetPageError(page);
3004		}
3005		cur = cur + iosize;
3006		pg_offset += iosize;
3007		nr++;
3008	}
3009done:
3010	if (nr == 0) {
3011		/* make sure the mapping tag for page dirty gets cleared */
3012		set_page_writeback(page);
3013		end_page_writeback(page);
3014	}
3015	unlock_page(page);
3016
3017done_unlocked:
3018
3019	/* drop our reference on any cached states */
3020	free_extent_state(cached_state);
3021	return 0;
3022}
3023
3024static int eb_wait(void *word)
 
 
 
 
 
 
 
3025{
3026	io_schedule();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3027	return 0;
3028}
3029
3030static void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3031{
3032	wait_on_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK, eb_wait,
3033		    TASK_UNINTERRUPTIBLE);
3034}
3035
3036static int lock_extent_buffer_for_io(struct extent_buffer *eb,
3037				     struct btrfs_fs_info *fs_info,
3038				     struct extent_page_data *epd)
 
3039{
3040	unsigned long i, num_pages;
3041	int flush = 0;
3042	int ret = 0;
3043
3044	if (!btrfs_try_tree_write_lock(eb)) {
3045		flush = 1;
3046		flush_write_bio(epd);
3047		btrfs_tree_lock(eb);
3048	}
3049
3050	if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3051		btrfs_tree_unlock(eb);
3052		if (!epd->sync_io)
3053			return 0;
3054		if (!flush) {
3055			flush_write_bio(epd);
3056			flush = 1;
3057		}
3058		while (1) {
3059			wait_on_extent_buffer_writeback(eb);
3060			btrfs_tree_lock(eb);
3061			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3062				break;
3063			btrfs_tree_unlock(eb);
3064		}
3065	}
3066
 
 
 
 
 
 
3067	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3068		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
 
3069		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3070		spin_lock(&fs_info->delalloc_lock);
3071		if (fs_info->dirty_metadata_bytes >= eb->len)
3072			fs_info->dirty_metadata_bytes -= eb->len;
3073		else
3074			WARN_ON(1);
3075		spin_unlock(&fs_info->delalloc_lock);
3076		ret = 1;
 
 
3077	}
3078
3079	btrfs_tree_unlock(eb);
3080
3081	if (!ret)
3082		return ret;
3083
3084	num_pages = num_extent_pages(eb->start, eb->len);
3085	for (i = 0; i < num_pages; i++) {
3086		struct page *p = extent_buffer_page(eb, i);
3087
3088		if (!trylock_page(p)) {
3089			if (!flush) {
3090				flush_write_bio(epd);
3091				flush = 1;
3092			}
3093			lock_page(p);
3094		}
3095	}
3096
3097	return ret;
3098}
3099
3100static void end_extent_buffer_writeback(struct extent_buffer *eb)
3101{
3102	clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3103	smp_mb__after_clear_bit();
3104	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3105}
3106
3107static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
3108{
3109	int uptodate = err == 0;
3110	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3111	struct extent_buffer *eb;
3112	int done;
3113
3114	do {
3115		struct page *page = bvec->bv_page;
3116
3117		bvec--;
3118		eb = (struct extent_buffer *)page->private;
3119		BUG_ON(!eb);
3120		done = atomic_dec_and_test(&eb->io_pages);
3121
3122		if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
3123			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
3124			ClearPageUptodate(page);
3125			SetPageError(page);
3126		}
3127
3128		end_page_writeback(page);
3129
3130		if (!done)
3131			continue;
3132
3133		end_extent_buffer_writeback(eb);
3134	} while (bvec >= bio->bi_io_vec);
3135
3136	bio_put(bio);
3137
3138}
3139
3140static int write_one_eb(struct extent_buffer *eb,
3141			struct btrfs_fs_info *fs_info,
3142			struct writeback_control *wbc,
3143			struct extent_page_data *epd)
3144{
3145	struct block_device *bdev = fs_info->fs_devices->latest_bdev;
 
3146	u64 offset = eb->start;
3147	unsigned long i, num_pages;
3148	int rw = (epd->sync_io ? WRITE_SYNC : WRITE);
 
3149	int ret = 0;
3150
3151	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
3152	num_pages = num_extent_pages(eb->start, eb->len);
3153	atomic_set(&eb->io_pages, num_pages);
 
 
 
3154	for (i = 0; i < num_pages; i++) {
3155		struct page *p = extent_buffer_page(eb, i);
3156
3157		clear_page_dirty_for_io(p);
3158		set_page_writeback(p);
3159		ret = submit_extent_page(rw, eb->tree, p, offset >> 9,
3160					 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
3161					 -1, end_bio_extent_buffer_writepage,
3162					 0, 0, 0);
 
3163		if (ret) {
3164			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
3165			SetPageError(p);
3166			if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3167				end_extent_buffer_writeback(eb);
3168			ret = -EIO;
3169			break;
3170		}
3171		offset += PAGE_CACHE_SIZE;
3172		update_nr_written(p, wbc, 1);
3173		unlock_page(p);
3174	}
3175
3176	if (unlikely(ret)) {
3177		for (; i < num_pages; i++) {
3178			struct page *p = extent_buffer_page(eb, i);
 
3179			unlock_page(p);
3180		}
3181	}
3182
3183	return ret;
3184}
3185
3186int btree_write_cache_pages(struct address_space *mapping,
3187				   struct writeback_control *wbc)
3188{
3189	struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3190	struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3191	struct extent_buffer *eb, *prev_eb = NULL;
3192	struct extent_page_data epd = {
3193		.bio = NULL,
3194		.tree = tree,
3195		.extent_locked = 0,
3196		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
 
3197	};
3198	int ret = 0;
3199	int done = 0;
3200	int nr_to_write_done = 0;
3201	struct pagevec pvec;
3202	int nr_pages;
3203	pgoff_t index;
3204	pgoff_t end;		/* Inclusive */
3205	int scanned = 0;
3206	int tag;
3207
3208	pagevec_init(&pvec, 0);
3209	if (wbc->range_cyclic) {
3210		index = mapping->writeback_index; /* Start from prev offset */
3211		end = -1;
3212	} else {
3213		index = wbc->range_start >> PAGE_CACHE_SHIFT;
3214		end = wbc->range_end >> PAGE_CACHE_SHIFT;
3215		scanned = 1;
3216	}
3217	if (wbc->sync_mode == WB_SYNC_ALL)
3218		tag = PAGECACHE_TAG_TOWRITE;
3219	else
3220		tag = PAGECACHE_TAG_DIRTY;
3221retry:
3222	if (wbc->sync_mode == WB_SYNC_ALL)
3223		tag_pages_for_writeback(mapping, index, end);
3224	while (!done && !nr_to_write_done && (index <= end) &&
3225	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3226			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3227		unsigned i;
3228
3229		scanned = 1;
3230		for (i = 0; i < nr_pages; i++) {
3231			struct page *page = pvec.pages[i];
3232
3233			if (!PagePrivate(page))
3234				continue;
3235
3236			if (!wbc->range_cyclic && page->index > end) {
3237				done = 1;
3238				break;
3239			}
3240
3241			eb = (struct extent_buffer *)page->private;
3242			if (!eb) {
3243				WARN_ON(1);
3244				continue;
3245			}
3246
3247			if (eb == prev_eb)
 
 
 
 
 
 
 
 
3248				continue;
 
3249
3250			if (!atomic_inc_not_zero(&eb->refs)) {
3251				WARN_ON(1);
3252				continue;
3253			}
3254
 
 
 
 
 
3255			prev_eb = eb;
3256			ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3257			if (!ret) {
3258				free_extent_buffer(eb);
3259				continue;
3260			}
3261
3262			ret = write_one_eb(eb, fs_info, wbc, &epd);
3263			if (ret) {
3264				done = 1;
3265				free_extent_buffer(eb);
3266				break;
3267			}
3268			free_extent_buffer(eb);
3269
3270			/*
3271			 * the filesystem may choose to bump up nr_to_write.
3272			 * We have to make sure to honor the new nr_to_write
3273			 * at any time
3274			 */
3275			nr_to_write_done = wbc->nr_to_write <= 0;
3276		}
3277		pagevec_release(&pvec);
3278		cond_resched();
3279	}
3280	if (!scanned && !done) {
3281		/*
3282		 * We hit the last page and there is more work to be done: wrap
3283		 * back to the start of the file
3284		 */
3285		scanned = 1;
3286		index = 0;
3287		goto retry;
3288	}
3289	flush_write_bio(&epd);
3290	return ret;
3291}
3292
3293/**
3294 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3295 * @mapping: address space structure to write
3296 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3297 * @writepage: function called for each page
3298 * @data: data passed to writepage function
3299 *
3300 * If a page is already under I/O, write_cache_pages() skips it, even
3301 * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
3302 * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
3303 * and msync() need to guarantee that all the data which was dirty at the time
3304 * the call was made get new I/O started against them.  If wbc->sync_mode is
3305 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3306 * existing IO to complete.
3307 */
3308static int extent_write_cache_pages(struct extent_io_tree *tree,
3309			     struct address_space *mapping,
3310			     struct writeback_control *wbc,
3311			     writepage_t writepage, void *data,
3312			     void (*flush_fn)(void *))
3313{
3314	struct inode *inode = mapping->host;
3315	int ret = 0;
3316	int done = 0;
 
3317	int nr_to_write_done = 0;
3318	struct pagevec pvec;
3319	int nr_pages;
3320	pgoff_t index;
3321	pgoff_t end;		/* Inclusive */
3322	int scanned = 0;
3323	int tag;
3324
3325	/*
3326	 * We have to hold onto the inode so that ordered extents can do their
3327	 * work when the IO finishes.  The alternative to this is failing to add
3328	 * an ordered extent if the igrab() fails there and that is a huge pain
3329	 * to deal with, so instead just hold onto the inode throughout the
3330	 * writepages operation.  If it fails here we are freeing up the inode
3331	 * anyway and we'd rather not waste our time writing out stuff that is
3332	 * going to be truncated anyway.
3333	 */
3334	if (!igrab(inode))
3335		return 0;
3336
3337	pagevec_init(&pvec, 0);
3338	if (wbc->range_cyclic) {
3339		index = mapping->writeback_index; /* Start from prev offset */
3340		end = -1;
3341	} else {
3342		index = wbc->range_start >> PAGE_CACHE_SHIFT;
3343		end = wbc->range_end >> PAGE_CACHE_SHIFT;
3344		scanned = 1;
3345	}
3346	if (wbc->sync_mode == WB_SYNC_ALL)
3347		tag = PAGECACHE_TAG_TOWRITE;
3348	else
3349		tag = PAGECACHE_TAG_DIRTY;
3350retry:
3351	if (wbc->sync_mode == WB_SYNC_ALL)
3352		tag_pages_for_writeback(mapping, index, end);
3353	while (!done && !nr_to_write_done && (index <= end) &&
3354	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3355			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3356		unsigned i;
3357
3358		scanned = 1;
3359		for (i = 0; i < nr_pages; i++) {
3360			struct page *page = pvec.pages[i];
3361
3362			/*
3363			 * At this point we hold neither mapping->tree_lock nor
3364			 * lock on the page itself: the page may be truncated or
3365			 * invalidated (changing page->mapping to NULL), or even
3366			 * swizzled back from swapper_space to tmpfs file
3367			 * mapping
3368			 */
3369			if (tree->ops &&
3370			    tree->ops->write_cache_pages_lock_hook) {
3371				tree->ops->write_cache_pages_lock_hook(page,
3372							       data, flush_fn);
3373			} else {
3374				if (!trylock_page(page)) {
3375					flush_fn(data);
3376					lock_page(page);
3377				}
3378			}
3379
3380			if (unlikely(page->mapping != mapping)) {
3381				unlock_page(page);
3382				continue;
3383			}
3384
3385			if (!wbc->range_cyclic && page->index > end) {
3386				done = 1;
3387				unlock_page(page);
3388				continue;
3389			}
3390
3391			if (wbc->sync_mode != WB_SYNC_NONE) {
3392				if (PageWriteback(page))
3393					flush_fn(data);
3394				wait_on_page_writeback(page);
3395			}
3396
3397			if (PageWriteback(page) ||
3398			    !clear_page_dirty_for_io(page)) {
3399				unlock_page(page);
3400				continue;
3401			}
3402
3403			ret = (*writepage)(page, wbc, data);
3404
3405			if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
3406				unlock_page(page);
3407				ret = 0;
3408			}
3409			if (ret)
3410				done = 1;
3411
3412			/*
3413			 * the filesystem may choose to bump up nr_to_write.
3414			 * We have to make sure to honor the new nr_to_write
3415			 * at any time
3416			 */
3417			nr_to_write_done = wbc->nr_to_write <= 0;
3418		}
3419		pagevec_release(&pvec);
3420		cond_resched();
3421	}
3422	if (!scanned && !done) {
3423		/*
3424		 * We hit the last page and there is more work to be done: wrap
3425		 * back to the start of the file
3426		 */
3427		scanned = 1;
3428		index = 0;
3429		goto retry;
3430	}
3431	btrfs_add_delayed_iput(inode);
3432	return ret;
3433}
3434
3435static void flush_epd_write_bio(struct extent_page_data *epd)
3436{
3437	if (epd->bio) {
3438		int rw = WRITE;
3439		int ret;
3440
3441		if (epd->sync_io)
3442			rw = WRITE_SYNC;
3443
3444		ret = submit_one_bio(rw, epd->bio, 0, 0);
3445		BUG_ON(ret < 0); /* -ENOMEM */
3446		epd->bio = NULL;
3447	}
3448}
3449
3450static noinline void flush_write_bio(void *data)
3451{
3452	struct extent_page_data *epd = data;
3453	flush_epd_write_bio(epd);
3454}
3455
3456int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
3457			  get_extent_t *get_extent,
3458			  struct writeback_control *wbc)
3459{
3460	int ret;
3461	struct extent_page_data epd = {
3462		.bio = NULL,
3463		.tree = tree,
3464		.get_extent = get_extent,
3465		.extent_locked = 0,
3466		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
 
3467	};
3468
3469	ret = __extent_writepage(page, wbc, &epd);
3470
3471	flush_epd_write_bio(&epd);
3472	return ret;
3473}
3474
3475int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
3476			      u64 start, u64 end, get_extent_t *get_extent,
3477			      int mode)
3478{
3479	int ret = 0;
3480	struct address_space *mapping = inode->i_mapping;
3481	struct page *page;
3482	unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
3483		PAGE_CACHE_SHIFT;
3484
3485	struct extent_page_data epd = {
3486		.bio = NULL,
3487		.tree = tree,
3488		.get_extent = get_extent,
3489		.extent_locked = 1,
3490		.sync_io = mode == WB_SYNC_ALL,
 
3491	};
3492	struct writeback_control wbc_writepages = {
3493		.sync_mode	= mode,
3494		.nr_to_write	= nr_pages * 2,
3495		.range_start	= start,
3496		.range_end	= end + 1,
3497	};
3498
3499	while (start <= end) {
3500		page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
3501		if (clear_page_dirty_for_io(page))
3502			ret = __extent_writepage(page, &wbc_writepages, &epd);
3503		else {
3504			if (tree->ops && tree->ops->writepage_end_io_hook)
3505				tree->ops->writepage_end_io_hook(page, start,
3506						 start + PAGE_CACHE_SIZE - 1,
3507						 NULL, 1);
3508			unlock_page(page);
3509		}
3510		page_cache_release(page);
3511		start += PAGE_CACHE_SIZE;
3512	}
3513
3514	flush_epd_write_bio(&epd);
3515	return ret;
3516}
3517
3518int extent_writepages(struct extent_io_tree *tree,
3519		      struct address_space *mapping,
3520		      get_extent_t *get_extent,
3521		      struct writeback_control *wbc)
3522{
3523	int ret = 0;
3524	struct extent_page_data epd = {
3525		.bio = NULL,
3526		.tree = tree,
3527		.get_extent = get_extent,
3528		.extent_locked = 0,
3529		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
 
3530	};
3531
3532	ret = extent_write_cache_pages(tree, mapping, wbc,
3533				       __extent_writepage, &epd,
3534				       flush_write_bio);
3535	flush_epd_write_bio(&epd);
3536	return ret;
3537}
3538
3539int extent_readpages(struct extent_io_tree *tree,
3540		     struct address_space *mapping,
3541		     struct list_head *pages, unsigned nr_pages,
3542		     get_extent_t get_extent)
3543{
3544	struct bio *bio = NULL;
3545	unsigned page_idx;
3546	unsigned long bio_flags = 0;
 
 
 
 
 
3547
3548	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
3549		struct page *page = list_entry(pages->prev, struct page, lru);
3550
3551		prefetchw(&page->flags);
3552		list_del(&page->lru);
3553		if (!add_to_page_cache_lru(page, mapping,
3554					page->index, GFP_NOFS)) {
3555			__extent_read_full_page(tree, page, get_extent,
3556						&bio, 0, &bio_flags);
3557		}
3558		page_cache_release(page);
3559	}
 
 
 
 
 
 
 
 
 
 
 
 
 
3560	BUG_ON(!list_empty(pages));
3561	if (bio)
3562		return submit_one_bio(READ, bio, 0, bio_flags);
3563	return 0;
3564}
3565
3566/*
3567 * basic invalidatepage code, this waits on any locked or writeback
3568 * ranges corresponding to the page, and then deletes any extent state
3569 * records from the tree
3570 */
3571int extent_invalidatepage(struct extent_io_tree *tree,
3572			  struct page *page, unsigned long offset)
3573{
3574	struct extent_state *cached_state = NULL;
3575	u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
3576	u64 end = start + PAGE_CACHE_SIZE - 1;
3577	size_t blocksize = page->mapping->host->i_sb->s_blocksize;
3578
3579	start += (offset + blocksize - 1) & ~(blocksize - 1);
3580	if (start > end)
3581		return 0;
3582
3583	lock_extent_bits(tree, start, end, 0, &cached_state);
3584	wait_on_page_writeback(page);
3585	clear_extent_bit(tree, start, end,
3586			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
3587			 EXTENT_DO_ACCOUNTING,
3588			 1, 1, &cached_state, GFP_NOFS);
3589	return 0;
3590}
3591
3592/*
3593 * a helper for releasepage, this tests for areas of the page that
3594 * are locked or under IO and drops the related state bits if it is safe
3595 * to drop the page.
3596 */
3597int try_release_extent_state(struct extent_map_tree *map,
3598			     struct extent_io_tree *tree, struct page *page,
3599			     gfp_t mask)
3600{
3601	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
3602	u64 end = start + PAGE_CACHE_SIZE - 1;
3603	int ret = 1;
3604
3605	if (test_range_bit(tree, start, end,
3606			   EXTENT_IOBITS, 0, NULL))
3607		ret = 0;
3608	else {
3609		if ((mask & GFP_NOFS) == GFP_NOFS)
3610			mask = GFP_NOFS;
3611		/*
3612		 * at this point we can safely clear everything except the
3613		 * locked bit and the nodatasum bit
3614		 */
3615		ret = clear_extent_bit(tree, start, end,
3616				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
3617				 0, 0, NULL, mask);
3618
3619		/* if clear_extent_bit failed for enomem reasons,
3620		 * we can't allow the release to continue.
3621		 */
3622		if (ret < 0)
3623			ret = 0;
3624		else
3625			ret = 1;
3626	}
3627	return ret;
3628}
3629
3630/*
3631 * a helper for releasepage.  As long as there are no locked extents
3632 * in the range corresponding to the page, both state records and extent
3633 * map records are removed
3634 */
3635int try_release_extent_mapping(struct extent_map_tree *map,
3636			       struct extent_io_tree *tree, struct page *page,
3637			       gfp_t mask)
3638{
3639	struct extent_map *em;
3640	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
3641	u64 end = start + PAGE_CACHE_SIZE - 1;
3642
3643	if ((mask & __GFP_WAIT) &&
3644	    page->mapping->host->i_size > 16 * 1024 * 1024) {
3645		u64 len;
3646		while (start <= end) {
3647			len = end - start + 1;
3648			write_lock(&map->lock);
3649			em = lookup_extent_mapping(map, start, len);
3650			if (!em) {
3651				write_unlock(&map->lock);
3652				break;
3653			}
3654			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
3655			    em->start != start) {
3656				write_unlock(&map->lock);
3657				free_extent_map(em);
3658				break;
3659			}
3660			if (!test_range_bit(tree, em->start,
3661					    extent_map_end(em) - 1,
3662					    EXTENT_LOCKED | EXTENT_WRITEBACK,
3663					    0, NULL)) {
3664				remove_extent_mapping(map, em);
3665				/* once for the rb tree */
3666				free_extent_map(em);
3667			}
3668			start = extent_map_end(em);
3669			write_unlock(&map->lock);
3670
3671			/* once for us */
3672			free_extent_map(em);
3673		}
3674	}
3675	return try_release_extent_state(map, tree, page, mask);
3676}
3677
3678/*
3679 * helper function for fiemap, which doesn't want to see any holes.
3680 * This maps until we find something past 'last'
3681 */
3682static struct extent_map *get_extent_skip_holes(struct inode *inode,
3683						u64 offset,
3684						u64 last,
3685						get_extent_t *get_extent)
3686{
3687	u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
3688	struct extent_map *em;
3689	u64 len;
3690
3691	if (offset >= last)
3692		return NULL;
3693
3694	while(1) {
3695		len = last - offset;
3696		if (len == 0)
3697			break;
3698		len = (len + sectorsize - 1) & ~(sectorsize - 1);
3699		em = get_extent(inode, NULL, 0, offset, len, 0);
3700		if (IS_ERR_OR_NULL(em))
3701			return em;
3702
3703		/* if this isn't a hole return it */
3704		if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
3705		    em->block_start != EXTENT_MAP_HOLE) {
3706			return em;
3707		}
3708
3709		/* this is a hole, advance to the next extent */
3710		offset = extent_map_end(em);
3711		free_extent_map(em);
3712		if (offset >= last)
3713			break;
3714	}
3715	return NULL;
3716}
3717
3718int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
3719		__u64 start, __u64 len, get_extent_t *get_extent)
3720{
3721	int ret = 0;
3722	u64 off = start;
3723	u64 max = start + len;
3724	u32 flags = 0;
3725	u32 found_type;
3726	u64 last;
3727	u64 last_for_get_extent = 0;
3728	u64 disko = 0;
3729	u64 isize = i_size_read(inode);
3730	struct btrfs_key found_key;
3731	struct extent_map *em = NULL;
3732	struct extent_state *cached_state = NULL;
3733	struct btrfs_path *path;
3734	struct btrfs_file_extent_item *item;
3735	int end = 0;
3736	u64 em_start = 0;
3737	u64 em_len = 0;
3738	u64 em_end = 0;
3739	unsigned long emflags;
3740
3741	if (len == 0)
3742		return -EINVAL;
3743
3744	path = btrfs_alloc_path();
3745	if (!path)
3746		return -ENOMEM;
3747	path->leave_spinning = 1;
3748
3749	start = ALIGN(start, BTRFS_I(inode)->root->sectorsize);
3750	len = ALIGN(len, BTRFS_I(inode)->root->sectorsize);
3751
3752	/*
3753	 * lookup the last file extent.  We're not using i_size here
3754	 * because there might be preallocation past i_size
3755	 */
3756	ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
3757				       path, btrfs_ino(inode), -1, 0);
3758	if (ret < 0) {
3759		btrfs_free_path(path);
3760		return ret;
3761	}
3762	WARN_ON(!ret);
3763	path->slots[0]--;
3764	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
3765			      struct btrfs_file_extent_item);
3766	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
3767	found_type = btrfs_key_type(&found_key);
3768
3769	/* No extents, but there might be delalloc bits */
3770	if (found_key.objectid != btrfs_ino(inode) ||
3771	    found_type != BTRFS_EXTENT_DATA_KEY) {
3772		/* have to trust i_size as the end */
3773		last = (u64)-1;
3774		last_for_get_extent = isize;
3775	} else {
3776		/*
3777		 * remember the start of the last extent.  There are a
3778		 * bunch of different factors that go into the length of the
3779		 * extent, so its much less complex to remember where it started
3780		 */
3781		last = found_key.offset;
3782		last_for_get_extent = last + 1;
3783	}
3784	btrfs_free_path(path);
3785
3786	/*
3787	 * we might have some extents allocated but more delalloc past those
3788	 * extents.  so, we trust isize unless the start of the last extent is
3789	 * beyond isize
3790	 */
3791	if (last < isize) {
3792		last = (u64)-1;
3793		last_for_get_extent = isize;
3794	}
3795
3796	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
3797			 &cached_state);
3798
3799	em = get_extent_skip_holes(inode, start, last_for_get_extent,
3800				   get_extent);
3801	if (!em)
3802		goto out;
3803	if (IS_ERR(em)) {
3804		ret = PTR_ERR(em);
3805		goto out;
3806	}
3807
3808	while (!end) {
3809		u64 offset_in_extent;
3810
3811		/* break if the extent we found is outside the range */
3812		if (em->start >= max || extent_map_end(em) < off)
3813			break;
3814
3815		/*
3816		 * get_extent may return an extent that starts before our
3817		 * requested range.  We have to make sure the ranges
3818		 * we return to fiemap always move forward and don't
3819		 * overlap, so adjust the offsets here
3820		 */
3821		em_start = max(em->start, off);
3822
3823		/*
3824		 * record the offset from the start of the extent
3825		 * for adjusting the disk offset below
 
 
3826		 */
3827		offset_in_extent = em_start - em->start;
 
3828		em_end = extent_map_end(em);
3829		em_len = em_end - em_start;
3830		emflags = em->flags;
3831		disko = 0;
3832		flags = 0;
3833
3834		/*
3835		 * bump off for our next call to get_extent
3836		 */
3837		off = extent_map_end(em);
3838		if (off >= max)
3839			end = 1;
3840
3841		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
3842			end = 1;
3843			flags |= FIEMAP_EXTENT_LAST;
3844		} else if (em->block_start == EXTENT_MAP_INLINE) {
3845			flags |= (FIEMAP_EXTENT_DATA_INLINE |
3846				  FIEMAP_EXTENT_NOT_ALIGNED);
3847		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
3848			flags |= (FIEMAP_EXTENT_DELALLOC |
3849				  FIEMAP_EXTENT_UNKNOWN);
3850		} else {
 
 
 
3851			disko = em->block_start + offset_in_extent;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3852		}
3853		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
3854			flags |= FIEMAP_EXTENT_ENCODED;
 
 
3855
3856		free_extent_map(em);
3857		em = NULL;
3858		if ((em_start >= last) || em_len == (u64)-1 ||
3859		   (last == (u64)-1 && isize <= em_end)) {
3860			flags |= FIEMAP_EXTENT_LAST;
3861			end = 1;
3862		}
3863
3864		/* now scan forward to see if this is really the last extent. */
3865		em = get_extent_skip_holes(inode, off, last_for_get_extent,
3866					   get_extent);
3867		if (IS_ERR(em)) {
3868			ret = PTR_ERR(em);
3869			goto out;
3870		}
3871		if (!em) {
3872			flags |= FIEMAP_EXTENT_LAST;
3873			end = 1;
3874		}
3875		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
3876					      em_len, flags);
3877		if (ret)
 
 
3878			goto out_free;
 
3879	}
3880out_free:
3881	free_extent_map(em);
3882out:
3883	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
 
3884			     &cached_state, GFP_NOFS);
3885	return ret;
3886}
3887
3888inline struct page *extent_buffer_page(struct extent_buffer *eb,
3889					      unsigned long i)
3890{
3891	return eb->pages[i];
 
3892}
3893
3894inline unsigned long num_extent_pages(u64 start, u64 len)
3895{
3896	return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
3897		(start >> PAGE_CACHE_SHIFT);
 
3898}
3899
3900static void __free_extent_buffer(struct extent_buffer *eb)
 
 
 
3901{
3902#if LEAK_DEBUG
3903	unsigned long flags;
3904	spin_lock_irqsave(&leak_lock, flags);
3905	list_del(&eb->leak_list);
3906	spin_unlock_irqrestore(&leak_lock, flags);
3907#endif
3908	if (eb->pages && eb->pages != eb->inline_pages)
3909		kfree(eb->pages);
3910	kmem_cache_free(extent_buffer_cache, eb);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3911}
3912
3913static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
3914						   u64 start,
3915						   unsigned long len,
3916						   gfp_t mask)
3917{
3918	struct extent_buffer *eb = NULL;
3919#if LEAK_DEBUG
3920	unsigned long flags;
3921#endif
3922
3923	eb = kmem_cache_zalloc(extent_buffer_cache, mask);
3924	if (eb == NULL)
3925		return NULL;
3926	eb->start = start;
3927	eb->len = len;
3928	eb->tree = tree;
3929	eb->bflags = 0;
3930	rwlock_init(&eb->lock);
3931	atomic_set(&eb->write_locks, 0);
3932	atomic_set(&eb->read_locks, 0);
3933	atomic_set(&eb->blocking_readers, 0);
3934	atomic_set(&eb->blocking_writers, 0);
3935	atomic_set(&eb->spinning_readers, 0);
3936	atomic_set(&eb->spinning_writers, 0);
3937	eb->lock_nested = 0;
3938	init_waitqueue_head(&eb->write_lock_wq);
3939	init_waitqueue_head(&eb->read_lock_wq);
3940
3941#if LEAK_DEBUG
3942	spin_lock_irqsave(&leak_lock, flags);
3943	list_add(&eb->leak_list, &buffers);
3944	spin_unlock_irqrestore(&leak_lock, flags);
3945#endif
3946	spin_lock_init(&eb->refs_lock);
3947	atomic_set(&eb->refs, 1);
3948	atomic_set(&eb->io_pages, 0);
3949
3950	if (len > MAX_INLINE_EXTENT_BUFFER_SIZE) {
3951		struct page **pages;
3952		int num_pages = (len + PAGE_CACHE_SIZE - 1) >>
3953			PAGE_CACHE_SHIFT;
3954		pages = kzalloc(num_pages, mask);
3955		if (!pages) {
3956			__free_extent_buffer(eb);
3957			return NULL;
3958		}
3959		eb->pages = pages;
3960	} else {
3961		eb->pages = eb->inline_pages;
3962	}
3963
3964	return eb;
3965}
3966
3967struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
3968{
3969	unsigned long i;
3970	struct page *p;
3971	struct extent_buffer *new;
3972	unsigned long num_pages = num_extent_pages(src->start, src->len);
3973
3974	new = __alloc_extent_buffer(NULL, src->start, src->len, GFP_ATOMIC);
3975	if (new == NULL)
3976		return NULL;
3977
3978	for (i = 0; i < num_pages; i++) {
3979		p = alloc_page(GFP_ATOMIC);
3980		BUG_ON(!p);
 
 
 
3981		attach_extent_buffer_page(new, p);
3982		WARN_ON(PageDirty(p));
3983		SetPageUptodate(p);
3984		new->pages[i] = p;
3985	}
3986
3987	copy_extent_buffer(new, src, 0, 0, src->len);
3988	set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
3989	set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
3990
3991	return new;
3992}
3993
3994struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len)
 
3995{
3996	struct extent_buffer *eb;
3997	unsigned long num_pages = num_extent_pages(0, len);
3998	unsigned long i;
3999
4000	eb = __alloc_extent_buffer(NULL, start, len, GFP_ATOMIC);
 
 
4001	if (!eb)
4002		return NULL;
4003
4004	for (i = 0; i < num_pages; i++) {
4005		eb->pages[i] = alloc_page(GFP_ATOMIC);
4006		if (!eb->pages[i])
4007			goto err;
4008	}
4009	set_extent_buffer_uptodate(eb);
4010	btrfs_set_header_nritems(eb, 0);
4011	set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4012
4013	return eb;
4014err:
4015	for (i--; i > 0; i--)
4016		__free_page(eb->pages[i]);
4017	__free_extent_buffer(eb);
4018	return NULL;
4019}
4020
4021static int extent_buffer_under_io(struct extent_buffer *eb)
4022{
4023	return (atomic_read(&eb->io_pages) ||
4024		test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4025		test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4026}
4027
4028/*
4029 * Helper for releasing extent buffer page.
4030 */
4031static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
4032						unsigned long start_idx)
4033{
4034	unsigned long index;
4035	unsigned long num_pages;
4036	struct page *page;
4037	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4038
4039	BUG_ON(extent_buffer_under_io(eb));
4040
4041	num_pages = num_extent_pages(eb->start, eb->len);
4042	index = start_idx + num_pages;
4043	if (start_idx >= index)
4044		return;
4045
4046	do {
4047		index--;
4048		page = extent_buffer_page(eb, index);
4049		if (page && mapped) {
4050			spin_lock(&page->mapping->private_lock);
4051			/*
4052			 * We do this since we'll remove the pages after we've
4053			 * removed the eb from the radix tree, so we could race
4054			 * and have this page now attached to the new eb.  So
4055			 * only clear page_private if it's still connected to
4056			 * this eb.
4057			 */
4058			if (PagePrivate(page) &&
4059			    page->private == (unsigned long)eb) {
4060				BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4061				BUG_ON(PageDirty(page));
4062				BUG_ON(PageWriteback(page));
4063				/*
4064				 * We need to make sure we haven't be attached
4065				 * to a new eb.
4066				 */
4067				ClearPagePrivate(page);
4068				set_page_private(page, 0);
4069				/* One for the page private */
4070				page_cache_release(page);
4071			}
4072			spin_unlock(&page->mapping->private_lock);
4073
4074		}
4075		if (page) {
4076			/* One for when we alloced the page */
4077			page_cache_release(page);
4078		}
4079	} while (index != start_idx);
4080}
4081
4082/*
4083 * Helper for releasing the extent buffer.
4084 */
4085static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4086{
4087	btrfs_release_extent_buffer_page(eb, 0);
4088	__free_extent_buffer(eb);
4089}
4090
4091static void check_buffer_tree_ref(struct extent_buffer *eb)
4092{
 
4093	/* the ref bit is tricky.  We have to make sure it is set
4094	 * if we have the buffer dirty.   Otherwise the
4095	 * code to free a buffer can end up dropping a dirty
4096	 * page
4097	 *
4098	 * Once the ref bit is set, it won't go away while the
4099	 * buffer is dirty or in writeback, and it also won't
4100	 * go away while we have the reference count on the
4101	 * eb bumped.
4102	 *
4103	 * We can't just set the ref bit without bumping the
4104	 * ref on the eb because free_extent_buffer might
4105	 * see the ref bit and try to clear it.  If this happens
4106	 * free_extent_buffer might end up dropping our original
4107	 * ref by mistake and freeing the page before we are able
4108	 * to add one more ref.
4109	 *
4110	 * So bump the ref count first, then set the bit.  If someone
4111	 * beat us to it, drop the ref we added.
4112	 */
4113	if (!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
 
 
 
 
 
4114		atomic_inc(&eb->refs);
4115		if (test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4116			atomic_dec(&eb->refs);
4117	}
4118}
4119
4120static void mark_extent_buffer_accessed(struct extent_buffer *eb)
 
4121{
4122	unsigned long num_pages, i;
4123
4124	check_buffer_tree_ref(eb);
4125
4126	num_pages = num_extent_pages(eb->start, eb->len);
4127	for (i = 0; i < num_pages; i++) {
4128		struct page *p = extent_buffer_page(eb, i);
4129		mark_page_accessed(p);
 
 
4130	}
4131}
4132
4133struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
4134					  u64 start, unsigned long len)
4135{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4136	unsigned long num_pages = num_extent_pages(start, len);
4137	unsigned long i;
4138	unsigned long index = start >> PAGE_CACHE_SHIFT;
4139	struct extent_buffer *eb;
4140	struct extent_buffer *exists = NULL;
4141	struct page *p;
4142	struct address_space *mapping = tree->mapping;
4143	int uptodate = 1;
4144	int ret;
4145
4146	rcu_read_lock();
4147	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
4148	if (eb && atomic_inc_not_zero(&eb->refs)) {
4149		rcu_read_unlock();
4150		mark_extent_buffer_accessed(eb);
4151		return eb;
4152	}
4153	rcu_read_unlock();
4154
4155	eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
4156	if (!eb)
4157		return NULL;
4158
4159	for (i = 0; i < num_pages; i++, index++) {
4160		p = find_or_create_page(mapping, index, GFP_NOFS);
4161		if (!p) {
4162			WARN_ON(1);
4163			goto free_eb;
4164		}
4165
4166		spin_lock(&mapping->private_lock);
4167		if (PagePrivate(p)) {
4168			/*
4169			 * We could have already allocated an eb for this page
4170			 * and attached one so lets see if we can get a ref on
4171			 * the existing eb, and if we can we know it's good and
4172			 * we can just return that one, else we know we can just
4173			 * overwrite page->private.
4174			 */
4175			exists = (struct extent_buffer *)p->private;
4176			if (atomic_inc_not_zero(&exists->refs)) {
4177				spin_unlock(&mapping->private_lock);
4178				unlock_page(p);
4179				page_cache_release(p);
4180				mark_extent_buffer_accessed(exists);
4181				goto free_eb;
4182			}
 
4183
4184			/*
4185			 * Do this so attach doesn't complain and we need to
4186			 * drop the ref the old guy had.
4187			 */
4188			ClearPagePrivate(p);
4189			WARN_ON(PageDirty(p));
4190			page_cache_release(p);
4191		}
4192		attach_extent_buffer_page(eb, p);
4193		spin_unlock(&mapping->private_lock);
4194		WARN_ON(PageDirty(p));
4195		mark_page_accessed(p);
4196		eb->pages[i] = p;
4197		if (!PageUptodate(p))
4198			uptodate = 0;
4199
4200		/*
4201		 * see below about how we avoid a nasty race with release page
4202		 * and why we unlock later
4203		 */
4204	}
4205	if (uptodate)
4206		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4207again:
4208	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
4209	if (ret)
4210		goto free_eb;
4211
4212	spin_lock(&tree->buffer_lock);
4213	ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
 
 
 
4214	if (ret == -EEXIST) {
4215		exists = radix_tree_lookup(&tree->buffer,
4216						start >> PAGE_CACHE_SHIFT);
4217		if (!atomic_inc_not_zero(&exists->refs)) {
4218			spin_unlock(&tree->buffer_lock);
4219			radix_tree_preload_end();
4220			exists = NULL;
4221			goto again;
4222		}
4223		spin_unlock(&tree->buffer_lock);
4224		radix_tree_preload_end();
4225		mark_extent_buffer_accessed(exists);
4226		goto free_eb;
4227	}
4228	/* add one reference for the tree */
4229	spin_lock(&eb->refs_lock);
4230	check_buffer_tree_ref(eb);
4231	spin_unlock(&eb->refs_lock);
4232	spin_unlock(&tree->buffer_lock);
4233	radix_tree_preload_end();
4234
4235	/*
4236	 * there is a race where release page may have
4237	 * tried to find this extent buffer in the radix
4238	 * but failed.  It will tell the VM it is safe to
4239	 * reclaim the, and it will clear the page private bit.
4240	 * We must make sure to set the page private bit properly
4241	 * after the extent buffer is in the radix tree so
4242	 * it doesn't get lost
4243	 */
4244	SetPageChecked(eb->pages[0]);
4245	for (i = 1; i < num_pages; i++) {
4246		p = extent_buffer_page(eb, i);
4247		ClearPageChecked(p);
4248		unlock_page(p);
4249	}
4250	unlock_page(eb->pages[0]);
4251	return eb;
4252
4253free_eb:
 
4254	for (i = 0; i < num_pages; i++) {
4255		if (eb->pages[i])
4256			unlock_page(eb->pages[i]);
4257	}
4258
4259	WARN_ON(!atomic_dec_and_test(&eb->refs));
4260	btrfs_release_extent_buffer(eb);
4261	return exists;
4262}
4263
4264struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
4265					 u64 start, unsigned long len)
4266{
4267	struct extent_buffer *eb;
4268
4269	rcu_read_lock();
4270	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
4271	if (eb && atomic_inc_not_zero(&eb->refs)) {
4272		rcu_read_unlock();
4273		mark_extent_buffer_accessed(eb);
4274		return eb;
4275	}
4276	rcu_read_unlock();
4277
4278	return NULL;
4279}
4280
4281static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
4282{
4283	struct extent_buffer *eb =
4284			container_of(head, struct extent_buffer, rcu_head);
4285
4286	__free_extent_buffer(eb);
4287}
4288
4289/* Expects to have eb->eb_lock already held */
4290static void release_extent_buffer(struct extent_buffer *eb, gfp_t mask)
4291{
4292	WARN_ON(atomic_read(&eb->refs) == 0);
4293	if (atomic_dec_and_test(&eb->refs)) {
4294		if (test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags)) {
4295			spin_unlock(&eb->refs_lock);
4296		} else {
4297			struct extent_io_tree *tree = eb->tree;
4298
4299			spin_unlock(&eb->refs_lock);
4300
4301			spin_lock(&tree->buffer_lock);
4302			radix_tree_delete(&tree->buffer,
4303					  eb->start >> PAGE_CACHE_SHIFT);
4304			spin_unlock(&tree->buffer_lock);
 
 
4305		}
4306
4307		/* Should be safe to release our pages at this point */
4308		btrfs_release_extent_buffer_page(eb, 0);
4309
 
 
 
 
 
4310		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
4311		return;
4312	}
4313	spin_unlock(&eb->refs_lock);
 
 
4314}
4315
4316void free_extent_buffer(struct extent_buffer *eb)
4317{
 
 
4318	if (!eb)
4319		return;
4320
 
 
 
 
 
 
 
 
 
4321	spin_lock(&eb->refs_lock);
4322	if (atomic_read(&eb->refs) == 2 &&
4323	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
4324		atomic_dec(&eb->refs);
4325
4326	if (atomic_read(&eb->refs) == 2 &&
4327	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
4328	    !extent_buffer_under_io(eb) &&
4329	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4330		atomic_dec(&eb->refs);
4331
4332	/*
4333	 * I know this is terrible, but it's temporary until we stop tracking
4334	 * the uptodate bits and such for the extent buffers.
4335	 */
4336	release_extent_buffer(eb, GFP_ATOMIC);
4337}
4338
4339void free_extent_buffer_stale(struct extent_buffer *eb)
4340{
4341	if (!eb)
4342		return;
4343
4344	spin_lock(&eb->refs_lock);
4345	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
4346
4347	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
4348	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4349		atomic_dec(&eb->refs);
4350	release_extent_buffer(eb, GFP_NOFS);
4351}
4352
4353void clear_extent_buffer_dirty(struct extent_buffer *eb)
4354{
4355	unsigned long i;
4356	unsigned long num_pages;
4357	struct page *page;
4358
4359	num_pages = num_extent_pages(eb->start, eb->len);
4360
4361	for (i = 0; i < num_pages; i++) {
4362		page = extent_buffer_page(eb, i);
4363		if (!PageDirty(page))
4364			continue;
4365
4366		lock_page(page);
4367		WARN_ON(!PagePrivate(page));
4368
4369		clear_page_dirty_for_io(page);
4370		spin_lock_irq(&page->mapping->tree_lock);
4371		if (!PageDirty(page)) {
4372			radix_tree_tag_clear(&page->mapping->page_tree,
4373						page_index(page),
4374						PAGECACHE_TAG_DIRTY);
4375		}
4376		spin_unlock_irq(&page->mapping->tree_lock);
4377		ClearPageError(page);
4378		unlock_page(page);
4379	}
4380	WARN_ON(atomic_read(&eb->refs) == 0);
4381}
4382
4383int set_extent_buffer_dirty(struct extent_buffer *eb)
4384{
4385	unsigned long i;
4386	unsigned long num_pages;
4387	int was_dirty = 0;
4388
4389	check_buffer_tree_ref(eb);
4390
4391	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
4392
4393	num_pages = num_extent_pages(eb->start, eb->len);
4394	WARN_ON(atomic_read(&eb->refs) == 0);
4395	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
4396
4397	for (i = 0; i < num_pages; i++)
4398		set_page_dirty(extent_buffer_page(eb, i));
4399	return was_dirty;
4400}
4401
4402static int range_straddles_pages(u64 start, u64 len)
4403{
4404	if (len < PAGE_CACHE_SIZE)
4405		return 1;
4406	if (start & (PAGE_CACHE_SIZE - 1))
4407		return 1;
4408	if ((start + len) & (PAGE_CACHE_SIZE - 1))
4409		return 1;
4410	return 0;
4411}
4412
4413int clear_extent_buffer_uptodate(struct extent_buffer *eb)
4414{
4415	unsigned long i;
4416	struct page *page;
4417	unsigned long num_pages;
4418
4419	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4420	num_pages = num_extent_pages(eb->start, eb->len);
4421	for (i = 0; i < num_pages; i++) {
4422		page = extent_buffer_page(eb, i);
4423		if (page)
4424			ClearPageUptodate(page);
4425	}
4426	return 0;
4427}
4428
4429int set_extent_buffer_uptodate(struct extent_buffer *eb)
4430{
4431	unsigned long i;
4432	struct page *page;
4433	unsigned long num_pages;
4434
4435	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4436	num_pages = num_extent_pages(eb->start, eb->len);
4437	for (i = 0; i < num_pages; i++) {
4438		page = extent_buffer_page(eb, i);
4439		SetPageUptodate(page);
4440	}
4441	return 0;
4442}
4443
4444int extent_range_uptodate(struct extent_io_tree *tree,
4445			  u64 start, u64 end)
4446{
4447	struct page *page;
4448	int ret;
4449	int pg_uptodate = 1;
4450	int uptodate;
4451	unsigned long index;
4452
4453	if (range_straddles_pages(start, end - start + 1)) {
4454		ret = test_range_bit(tree, start, end,
4455				     EXTENT_UPTODATE, 1, NULL);
4456		if (ret)
4457			return 1;
4458	}
4459	while (start <= end) {
4460		index = start >> PAGE_CACHE_SHIFT;
4461		page = find_get_page(tree->mapping, index);
4462		if (!page)
4463			return 1;
4464		uptodate = PageUptodate(page);
4465		page_cache_release(page);
4466		if (!uptodate) {
4467			pg_uptodate = 0;
4468			break;
4469		}
4470		start += PAGE_CACHE_SIZE;
4471	}
4472	return pg_uptodate;
4473}
4474
4475int extent_buffer_uptodate(struct extent_buffer *eb)
4476{
4477	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4478}
4479
4480int read_extent_buffer_pages(struct extent_io_tree *tree,
4481			     struct extent_buffer *eb, u64 start, int wait,
4482			     get_extent_t *get_extent, int mirror_num)
4483{
4484	unsigned long i;
4485	unsigned long start_i;
4486	struct page *page;
4487	int err;
4488	int ret = 0;
4489	int locked_pages = 0;
4490	int all_uptodate = 1;
4491	unsigned long num_pages;
4492	unsigned long num_reads = 0;
4493	struct bio *bio = NULL;
4494	unsigned long bio_flags = 0;
4495
4496	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
4497		return 0;
4498
4499	if (start) {
4500		WARN_ON(start < eb->start);
4501		start_i = (start >> PAGE_CACHE_SHIFT) -
4502			(eb->start >> PAGE_CACHE_SHIFT);
4503	} else {
4504		start_i = 0;
4505	}
4506
4507	num_pages = num_extent_pages(eb->start, eb->len);
4508	for (i = start_i; i < num_pages; i++) {
4509		page = extent_buffer_page(eb, i);
4510		if (wait == WAIT_NONE) {
4511			if (!trylock_page(page))
4512				goto unlock_exit;
4513		} else {
4514			lock_page(page);
4515		}
4516		locked_pages++;
4517		if (!PageUptodate(page)) {
4518			num_reads++;
4519			all_uptodate = 0;
4520		}
4521	}
4522	if (all_uptodate) {
4523		if (start_i == 0)
4524			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4525		goto unlock_exit;
4526	}
4527
4528	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
4529	eb->read_mirror = 0;
4530	atomic_set(&eb->io_pages, num_reads);
4531	for (i = start_i; i < num_pages; i++) {
4532		page = extent_buffer_page(eb, i);
4533		if (!PageUptodate(page)) {
4534			ClearPageError(page);
4535			err = __extent_read_full_page(tree, page,
4536						      get_extent, &bio,
4537						      mirror_num, &bio_flags);
 
4538			if (err)
4539				ret = err;
4540		} else {
4541			unlock_page(page);
4542		}
4543	}
4544
4545	if (bio) {
4546		err = submit_one_bio(READ, bio, mirror_num, bio_flags);
 
4547		if (err)
4548			return err;
4549	}
4550
4551	if (ret || wait != WAIT_COMPLETE)
4552		return ret;
4553
4554	for (i = start_i; i < num_pages; i++) {
4555		page = extent_buffer_page(eb, i);
4556		wait_on_page_locked(page);
4557		if (!PageUptodate(page))
4558			ret = -EIO;
4559	}
4560
4561	return ret;
4562
4563unlock_exit:
4564	i = start_i;
4565	while (locked_pages > 0) {
4566		page = extent_buffer_page(eb, i);
4567		i++;
4568		unlock_page(page);
4569		locked_pages--;
4570	}
4571	return ret;
4572}
4573
4574void read_extent_buffer(struct extent_buffer *eb, void *dstv,
4575			unsigned long start,
4576			unsigned long len)
4577{
4578	size_t cur;
4579	size_t offset;
4580	struct page *page;
4581	char *kaddr;
4582	char *dst = (char *)dstv;
4583	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4584	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4585
4586	WARN_ON(start > eb->len);
4587	WARN_ON(start + len > eb->start + eb->len);
4588
4589	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4590
4591	while (len > 0) {
4592		page = extent_buffer_page(eb, i);
4593
4594		cur = min(len, (PAGE_CACHE_SIZE - offset));
4595		kaddr = page_address(page);
4596		memcpy(dst, kaddr + offset, cur);
4597
4598		dst += cur;
4599		len -= cur;
4600		offset = 0;
4601		i++;
4602	}
4603}
4604
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4605int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
4606			       unsigned long min_len, char **map,
4607			       unsigned long *map_start,
4608			       unsigned long *map_len)
4609{
4610	size_t offset = start & (PAGE_CACHE_SIZE - 1);
4611	char *kaddr;
4612	struct page *p;
4613	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4614	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4615	unsigned long end_i = (start_offset + start + min_len - 1) >>
4616		PAGE_CACHE_SHIFT;
4617
4618	if (i != end_i)
4619		return -EINVAL;
4620
4621	if (i == 0) {
4622		offset = start_offset;
4623		*map_start = 0;
4624	} else {
4625		offset = 0;
4626		*map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
4627	}
4628
4629	if (start + min_len > eb->len) {
4630		printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
4631		       "wanted %lu %lu\n", (unsigned long long)eb->start,
4632		       eb->len, start, min_len);
4633		WARN_ON(1);
4634		return -EINVAL;
4635	}
4636
4637	p = extent_buffer_page(eb, i);
4638	kaddr = page_address(p);
4639	*map = kaddr + offset;
4640	*map_len = PAGE_CACHE_SIZE - offset;
4641	return 0;
4642}
4643
4644int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
4645			  unsigned long start,
4646			  unsigned long len)
4647{
4648	size_t cur;
4649	size_t offset;
4650	struct page *page;
4651	char *kaddr;
4652	char *ptr = (char *)ptrv;
4653	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4654	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4655	int ret = 0;
4656
4657	WARN_ON(start > eb->len);
4658	WARN_ON(start + len > eb->start + eb->len);
4659
4660	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4661
4662	while (len > 0) {
4663		page = extent_buffer_page(eb, i);
4664
4665		cur = min(len, (PAGE_CACHE_SIZE - offset));
4666
4667		kaddr = page_address(page);
4668		ret = memcmp(ptr, kaddr + offset, cur);
4669		if (ret)
4670			break;
4671
4672		ptr += cur;
4673		len -= cur;
4674		offset = 0;
4675		i++;
4676	}
4677	return ret;
4678}
4679
4680void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
4681			 unsigned long start, unsigned long len)
4682{
4683	size_t cur;
4684	size_t offset;
4685	struct page *page;
4686	char *kaddr;
4687	char *src = (char *)srcv;
4688	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4689	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4690
4691	WARN_ON(start > eb->len);
4692	WARN_ON(start + len > eb->start + eb->len);
4693
4694	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4695
4696	while (len > 0) {
4697		page = extent_buffer_page(eb, i);
4698		WARN_ON(!PageUptodate(page));
4699
4700		cur = min(len, PAGE_CACHE_SIZE - offset);
4701		kaddr = page_address(page);
4702		memcpy(kaddr + offset, src, cur);
4703
4704		src += cur;
4705		len -= cur;
4706		offset = 0;
4707		i++;
4708	}
4709}
4710
4711void memset_extent_buffer(struct extent_buffer *eb, char c,
4712			  unsigned long start, unsigned long len)
4713{
4714	size_t cur;
4715	size_t offset;
4716	struct page *page;
4717	char *kaddr;
4718	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4719	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4720
4721	WARN_ON(start > eb->len);
4722	WARN_ON(start + len > eb->start + eb->len);
4723
4724	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4725
4726	while (len > 0) {
4727		page = extent_buffer_page(eb, i);
4728		WARN_ON(!PageUptodate(page));
4729
4730		cur = min(len, PAGE_CACHE_SIZE - offset);
4731		kaddr = page_address(page);
4732		memset(kaddr + offset, c, cur);
4733
4734		len -= cur;
4735		offset = 0;
4736		i++;
4737	}
4738}
4739
4740void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
4741			unsigned long dst_offset, unsigned long src_offset,
4742			unsigned long len)
4743{
4744	u64 dst_len = dst->len;
4745	size_t cur;
4746	size_t offset;
4747	struct page *page;
4748	char *kaddr;
4749	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
4750	unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
4751
4752	WARN_ON(src->len != dst_len);
4753
4754	offset = (start_offset + dst_offset) &
4755		((unsigned long)PAGE_CACHE_SIZE - 1);
4756
4757	while (len > 0) {
4758		page = extent_buffer_page(dst, i);
4759		WARN_ON(!PageUptodate(page));
4760
4761		cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
4762
4763		kaddr = page_address(page);
4764		read_extent_buffer(src, kaddr + offset, src_offset, cur);
4765
4766		src_offset += cur;
4767		len -= cur;
4768		offset = 0;
4769		i++;
4770	}
4771}
4772
4773static void move_pages(struct page *dst_page, struct page *src_page,
4774		       unsigned long dst_off, unsigned long src_off,
4775		       unsigned long len)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4776{
4777	char *dst_kaddr = page_address(dst_page);
4778	if (dst_page == src_page) {
4779		memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
4780	} else {
4781		char *src_kaddr = page_address(src_page);
4782		char *p = dst_kaddr + dst_off + len;
4783		char *s = src_kaddr + src_off + len;
 
 
 
4784
4785		while (len--)
4786			*--p = *--s;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4787	}
4788}
4789
4790static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
4791{
4792	unsigned long distance = (src > dst) ? src - dst : dst - src;
4793	return distance < len;
4794}
4795
4796static void copy_pages(struct page *dst_page, struct page *src_page,
4797		       unsigned long dst_off, unsigned long src_off,
4798		       unsigned long len)
4799{
4800	char *dst_kaddr = page_address(dst_page);
4801	char *src_kaddr;
4802	int must_memmove = 0;
4803
4804	if (dst_page != src_page) {
4805		src_kaddr = page_address(src_page);
4806	} else {
4807		src_kaddr = dst_kaddr;
4808		if (areas_overlap(src_off, dst_off, len))
4809			must_memmove = 1;
4810	}
4811
4812	if (must_memmove)
4813		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
4814	else
4815		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
4816}
4817
4818void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
4819			   unsigned long src_offset, unsigned long len)
4820{
4821	size_t cur;
4822	size_t dst_off_in_page;
4823	size_t src_off_in_page;
4824	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
4825	unsigned long dst_i;
4826	unsigned long src_i;
4827
4828	if (src_offset + len > dst->len) {
4829		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
4830		       "len %lu dst len %lu\n", src_offset, len, dst->len);
 
4831		BUG_ON(1);
4832	}
4833	if (dst_offset + len > dst->len) {
4834		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
4835		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
 
4836		BUG_ON(1);
4837	}
4838
4839	while (len > 0) {
4840		dst_off_in_page = (start_offset + dst_offset) &
4841			((unsigned long)PAGE_CACHE_SIZE - 1);
4842		src_off_in_page = (start_offset + src_offset) &
4843			((unsigned long)PAGE_CACHE_SIZE - 1);
4844
4845		dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
4846		src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
4847
4848		cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
4849					       src_off_in_page));
4850		cur = min_t(unsigned long, cur,
4851			(unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
4852
4853		copy_pages(extent_buffer_page(dst, dst_i),
4854			   extent_buffer_page(dst, src_i),
4855			   dst_off_in_page, src_off_in_page, cur);
4856
4857		src_offset += cur;
4858		dst_offset += cur;
4859		len -= cur;
4860	}
4861}
4862
4863void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
4864			   unsigned long src_offset, unsigned long len)
4865{
4866	size_t cur;
4867	size_t dst_off_in_page;
4868	size_t src_off_in_page;
4869	unsigned long dst_end = dst_offset + len - 1;
4870	unsigned long src_end = src_offset + len - 1;
4871	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
4872	unsigned long dst_i;
4873	unsigned long src_i;
4874
4875	if (src_offset + len > dst->len) {
4876		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
4877		       "len %lu len %lu\n", src_offset, len, dst->len);
4878		BUG_ON(1);
4879	}
4880	if (dst_offset + len > dst->len) {
4881		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
4882		       "len %lu len %lu\n", dst_offset, len, dst->len);
4883		BUG_ON(1);
4884	}
4885	if (dst_offset < src_offset) {
4886		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
4887		return;
4888	}
4889	while (len > 0) {
4890		dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
4891		src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
4892
4893		dst_off_in_page = (start_offset + dst_end) &
4894			((unsigned long)PAGE_CACHE_SIZE - 1);
4895		src_off_in_page = (start_offset + src_end) &
4896			((unsigned long)PAGE_CACHE_SIZE - 1);
4897
4898		cur = min_t(unsigned long, len, src_off_in_page + 1);
4899		cur = min(cur, dst_off_in_page + 1);
4900		move_pages(extent_buffer_page(dst, dst_i),
4901			   extent_buffer_page(dst, src_i),
4902			   dst_off_in_page - cur + 1,
4903			   src_off_in_page - cur + 1, cur);
4904
4905		dst_end -= cur;
4906		src_end -= cur;
4907		len -= cur;
4908	}
4909}
4910
4911int try_release_extent_buffer(struct page *page, gfp_t mask)
4912{
4913	struct extent_buffer *eb;
4914
4915	/*
4916	 * We need to make sure noboody is attaching this page to an eb right
4917	 * now.
4918	 */
4919	spin_lock(&page->mapping->private_lock);
4920	if (!PagePrivate(page)) {
4921		spin_unlock(&page->mapping->private_lock);
4922		return 1;
4923	}
4924
4925	eb = (struct extent_buffer *)page->private;
4926	BUG_ON(!eb);
4927
4928	/*
4929	 * This is a little awful but should be ok, we need to make sure that
4930	 * the eb doesn't disappear out from under us while we're looking at
4931	 * this page.
4932	 */
4933	spin_lock(&eb->refs_lock);
4934	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
4935		spin_unlock(&eb->refs_lock);
4936		spin_unlock(&page->mapping->private_lock);
4937		return 0;
4938	}
4939	spin_unlock(&page->mapping->private_lock);
4940
4941	if ((mask & GFP_NOFS) == GFP_NOFS)
4942		mask = GFP_NOFS;
4943
4944	/*
4945	 * If tree ref isn't set then we know the ref on this eb is a real ref,
4946	 * so just return, this page will likely be freed soon anyway.
4947	 */
4948	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
4949		spin_unlock(&eb->refs_lock);
4950		return 0;
4951	}
4952	release_extent_buffer(eb, mask);
4953
4954	return 1;
4955}