extent_io.c 99.4 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include "extent_io.h"
#include "extent_map.h"
15
#include "compat.h"
16 17
#include "ctree.h"
#include "btrfs_inode.h"
18 19 20 21 22 23

static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;

static LIST_HEAD(buffers);
static LIST_HEAD(states);
C
Chris Mason 已提交
24

25
#define LEAK_DEBUG 0
26
#if LEAK_DEBUG
C
Chris Mason 已提交
27
static DEFINE_SPINLOCK(leak_lock);
C
Chris Mason 已提交
28
#endif
29 30 31 32 33 34 35 36 37 38 39 40 41

#define BUFFER_LRU_MAX 64

struct tree_entry {
	u64 start;
	u64 end;
	struct rb_node rb_node;
};

struct extent_page_data {
	struct bio *bio;
	struct extent_io_tree *tree;
	get_extent_t *get_extent;
42 43 44 45

	/* tells writepage not to lock the state bits for this range
	 * it still does the unlocking
	 */
46 47 48 49
	unsigned int extent_locked:1;

	/* tells the submit_bio code to use a WRITE_SYNC */
	unsigned int sync_io:1;
50 51 52 53
};

int __init extent_io_init(void)
{
54 55 56
	extent_state_cache = kmem_cache_create("extent_state",
			sizeof(struct extent_state), 0,
			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
57 58 59
	if (!extent_state_cache)
		return -ENOMEM;

60 61 62
	extent_buffer_cache = kmem_cache_create("extent_buffers",
			sizeof(struct extent_buffer), 0,
			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
63 64 65 66 67 68 69 70 71 72 73 74
	if (!extent_buffer_cache)
		goto free_state_cache;
	return 0;

free_state_cache:
	kmem_cache_destroy(extent_state_cache);
	return -ENOMEM;
}

void extent_io_exit(void)
{
	struct extent_state *state;
75
	struct extent_buffer *eb;
76 77

	while (!list_empty(&states)) {
78
		state = list_entry(states.next, struct extent_state, leak_list);
C
Chris Mason 已提交
79 80 81 82 83
		printk(KERN_ERR "btrfs state leak: start %llu end %llu "
		       "state %lu in tree %p refs %d\n",
		       (unsigned long long)state->start,
		       (unsigned long long)state->end,
		       state->state, state->tree, atomic_read(&state->refs));
84
		list_del(&state->leak_list);
85 86 87 88
		kmem_cache_free(extent_state_cache, state);

	}

89 90
	while (!list_empty(&buffers)) {
		eb = list_entry(buffers.next, struct extent_buffer, leak_list);
C
Chris Mason 已提交
91 92 93
		printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
		       "refs %d\n", (unsigned long long)eb->start,
		       eb->len, atomic_read(&eb->refs));
94 95 96
		list_del(&eb->leak_list);
		kmem_cache_free(extent_buffer_cache, eb);
	}
97 98 99 100 101 102 103 104 105
	if (extent_state_cache)
		kmem_cache_destroy(extent_state_cache);
	if (extent_buffer_cache)
		kmem_cache_destroy(extent_buffer_cache);
}

void extent_io_tree_init(struct extent_io_tree *tree,
			  struct address_space *mapping, gfp_t mask)
{
106
	tree->state = RB_ROOT;
107
	INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
108 109
	tree->ops = NULL;
	tree->dirty_bytes = 0;
110
	spin_lock_init(&tree->lock);
111
	spin_lock_init(&tree->buffer_lock);
112 113 114
	tree->mapping = mapping;
}

115
static struct extent_state *alloc_extent_state(gfp_t mask)
116 117
{
	struct extent_state *state;
118
#if LEAK_DEBUG
119
	unsigned long flags;
C
Chris Mason 已提交
120
#endif
121 122

	state = kmem_cache_alloc(extent_state_cache, mask);
123
	if (!state)
124 125 126
		return state;
	state->state = 0;
	state->private = 0;
127
	state->tree = NULL;
128
#if LEAK_DEBUG
129 130 131
	spin_lock_irqsave(&leak_lock, flags);
	list_add(&state->leak_list, &states);
	spin_unlock_irqrestore(&leak_lock, flags);
C
Chris Mason 已提交
132
#endif
133 134 135 136 137
	atomic_set(&state->refs, 1);
	init_waitqueue_head(&state->wq);
	return state;
}

138
void free_extent_state(struct extent_state *state)
139 140 141 142
{
	if (!state)
		return;
	if (atomic_dec_and_test(&state->refs)) {
143
#if LEAK_DEBUG
144
		unsigned long flags;
C
Chris Mason 已提交
145
#endif
146
		WARN_ON(state->tree);
147
#if LEAK_DEBUG
148 149 150
		spin_lock_irqsave(&leak_lock, flags);
		list_del(&state->leak_list);
		spin_unlock_irqrestore(&leak_lock, flags);
C
Chris Mason 已提交
151
#endif
152 153 154 155 156 157 158
		kmem_cache_free(extent_state_cache, state);
	}
}

static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
				   struct rb_node *node)
{
C
Chris Mason 已提交
159 160
	struct rb_node **p = &root->rb_node;
	struct rb_node *parent = NULL;
161 162
	struct tree_entry *entry;

C
Chris Mason 已提交
163
	while (*p) {
164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180
		parent = *p;
		entry = rb_entry(parent, struct tree_entry, rb_node);

		if (offset < entry->start)
			p = &(*p)->rb_left;
		else if (offset > entry->end)
			p = &(*p)->rb_right;
		else
			return parent;
	}

	entry = rb_entry(node, struct tree_entry, rb_node);
	rb_link_node(node, parent, p);
	rb_insert_color(node, root);
	return NULL;
}

181
static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
182 183 184
				     struct rb_node **prev_ret,
				     struct rb_node **next_ret)
{
185
	struct rb_root *root = &tree->state;
C
Chris Mason 已提交
186
	struct rb_node *n = root->rb_node;
187 188 189 190 191
	struct rb_node *prev = NULL;
	struct rb_node *orig_prev = NULL;
	struct tree_entry *entry;
	struct tree_entry *prev_entry = NULL;

C
Chris Mason 已提交
192
	while (n) {
193 194 195 196 197 198 199 200
		entry = rb_entry(n, struct tree_entry, rb_node);
		prev = n;
		prev_entry = entry;

		if (offset < entry->start)
			n = n->rb_left;
		else if (offset > entry->end)
			n = n->rb_right;
C
Chris Mason 已提交
201
		else
202 203 204 205 206
			return n;
	}

	if (prev_ret) {
		orig_prev = prev;
C
Chris Mason 已提交
207
		while (prev && offset > prev_entry->end) {
208 209 210 211 212 213 214 215 216
			prev = rb_next(prev);
			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
		}
		*prev_ret = prev;
		prev = orig_prev;
	}

	if (next_ret) {
		prev_entry = rb_entry(prev, struct tree_entry, rb_node);
C
Chris Mason 已提交
217
		while (prev && offset < prev_entry->start) {
218 219 220 221 222 223 224 225
			prev = rb_prev(prev);
			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
		}
		*next_ret = prev;
	}
	return NULL;
}

226 227
static inline struct rb_node *tree_search(struct extent_io_tree *tree,
					  u64 offset)
228
{
229
	struct rb_node *prev = NULL;
230
	struct rb_node *ret;
231

232
	ret = __etree_search(tree, offset, &prev, NULL);
C
Chris Mason 已提交
233
	if (!ret)
234 235 236 237
		return prev;
	return ret;
}

J
Josef Bacik 已提交
238 239 240 241 242 243 244 245
static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
		     struct extent_state *other)
{
	if (tree->ops && tree->ops->merge_extent_hook)
		tree->ops->merge_extent_hook(tree->mapping->host, new,
					     other);
}

246 247 248 249 250 251 252 253 254 255 256 257 258 259 260
/*
 * utility function to look for merge candidates inside a given range.
 * Any extents with matching state are merged together into a single
 * extent in the tree.  Extents with EXTENT_IO in their state field
 * are not merged because the end_io handlers need to be able to do
 * operations on them without sleeping (or doing allocations/splits).
 *
 * This should be called with the tree lock held.
 */
static int merge_state(struct extent_io_tree *tree,
		       struct extent_state *state)
{
	struct extent_state *other;
	struct rb_node *other_node;

261
	if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
262 263 264 265 266 267 268
		return 0;

	other_node = rb_prev(&state->rb_node);
	if (other_node) {
		other = rb_entry(other_node, struct extent_state, rb_node);
		if (other->end == state->start - 1 &&
		    other->state == state->state) {
J
Josef Bacik 已提交
269
			merge_cb(tree, state, other);
270
			state->start = other->start;
271
			other->tree = NULL;
272 273 274 275 276 277 278 279 280
			rb_erase(&other->rb_node, &tree->state);
			free_extent_state(other);
		}
	}
	other_node = rb_next(&state->rb_node);
	if (other_node) {
		other = rb_entry(other_node, struct extent_state, rb_node);
		if (other->start == state->end + 1 &&
		    other->state == state->state) {
J
Josef Bacik 已提交
281
			merge_cb(tree, state, other);
282
			other->start = state->start;
283
			state->tree = NULL;
284 285
			rb_erase(&state->rb_node, &tree->state);
			free_extent_state(state);
J
Josef Bacik 已提交
286
			state = NULL;
287 288
		}
	}
J
Josef Bacik 已提交
289

290 291 292
	return 0;
}

J
Josef Bacik 已提交
293
static int set_state_cb(struct extent_io_tree *tree,
294
			 struct extent_state *state, int *bits)
295 296
{
	if (tree->ops && tree->ops->set_bit_hook) {
J
Josef Bacik 已提交
297
		return tree->ops->set_bit_hook(tree->mapping->host,
298
					       state, bits);
299
	}
J
Josef Bacik 已提交
300 301

	return 0;
302 303 304
}

static void clear_state_cb(struct extent_io_tree *tree,
305
			   struct extent_state *state, int *bits)
306
{
J
Josef Bacik 已提交
307 308
	if (tree->ops && tree->ops->clear_bit_hook)
		tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
309 310
}

311 312 313 314 315 316 317 318 319 320 321 322
/*
 * insert an extent_state struct into the tree.  'bits' are set on the
 * struct before it is inserted.
 *
 * This may return -EEXIST if the extent is already there, in which case the
 * state struct is freed.
 *
 * The tree lock is not taken internally.  This is a utility function and
 * probably isn't what you want to call (see set/clear_extent_bit).
 */
static int insert_state(struct extent_io_tree *tree,
			struct extent_state *state, u64 start, u64 end,
323
			int *bits)
324 325
{
	struct rb_node *node;
326
	int bits_to_set = *bits & ~EXTENT_CTLBITS;
J
Josef Bacik 已提交
327
	int ret;
328 329

	if (end < start) {
C
Chris Mason 已提交
330 331 332
		printk(KERN_ERR "btrfs end < start %llu %llu\n",
		       (unsigned long long)end,
		       (unsigned long long)start);
333 334 335 336
		WARN_ON(1);
	}
	state->start = start;
	state->end = end;
J
Josef Bacik 已提交
337 338 339 340
	ret = set_state_cb(tree, state, bits);
	if (ret)
		return ret;

341
	if (bits_to_set & EXTENT_DIRTY)
J
Josef Bacik 已提交
342
		tree->dirty_bytes += end - start + 1;
343
	state->state |= bits_to_set;
344 345 346 347
	node = tree_insert(&tree->state, end, &state->rb_node);
	if (node) {
		struct extent_state *found;
		found = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
348 349 350 351
		printk(KERN_ERR "btrfs found node %llu %llu on insert of "
		       "%llu %llu\n", (unsigned long long)found->start,
		       (unsigned long long)found->end,
		       (unsigned long long)start, (unsigned long long)end);
352 353 354
		free_extent_state(state);
		return -EEXIST;
	}
355
	state->tree = tree;
356 357 358 359
	merge_state(tree, state);
	return 0;
}

J
Josef Bacik 已提交
360 361 362 363 364 365 366 367 368
static int split_cb(struct extent_io_tree *tree, struct extent_state *orig,
		     u64 split)
{
	if (tree->ops && tree->ops->split_extent_hook)
		return tree->ops->split_extent_hook(tree->mapping->host,
						    orig, split);
	return 0;
}

369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386
/*
 * split a given extent state struct in two, inserting the preallocated
 * struct 'prealloc' as the newly created second half.  'split' indicates an
 * offset inside 'orig' where it should be split.
 *
 * Before calling,
 * the tree has 'orig' at [orig->start, orig->end].  After calling, there
 * are two extent state structs in the tree:
 * prealloc: [orig->start, split - 1]
 * orig: [ split, orig->end ]
 *
 * The tree locks are not taken by this function. They need to be held
 * by the caller.
 */
static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
		       struct extent_state *prealloc, u64 split)
{
	struct rb_node *node;
J
Josef Bacik 已提交
387 388 389

	split_cb(tree, orig, split);

390 391 392 393 394 395 396 397 398 399
	prealloc->start = orig->start;
	prealloc->end = split - 1;
	prealloc->state = orig->state;
	orig->start = split;

	node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
	if (node) {
		free_extent_state(prealloc);
		return -EEXIST;
	}
400
	prealloc->tree = tree;
401 402 403 404 405 406 407 408 409 410 411 412
	return 0;
}

/*
 * utility function to clear some bits in an extent state struct.
 * it will optionally wake up any one waiting on this state (wake == 1), or
 * forcibly remove the state from the tree (delete == 1).
 *
 * If no bits are set on the state struct after clearing things, the
 * struct is freed and removed from the tree
 */
static int clear_state_bit(struct extent_io_tree *tree,
413 414
			    struct extent_state *state,
			    int *bits, int wake)
415
{
416
	int bits_to_clear = *bits & ~EXTENT_CTLBITS;
417
	int ret = state->state & bits_to_clear;
418

419
	if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
420 421 422 423
		u64 range = state->end - state->start + 1;
		WARN_ON(range > tree->dirty_bytes);
		tree->dirty_bytes -= range;
	}
424
	clear_state_cb(tree, state, bits);
425
	state->state &= ~bits_to_clear;
426 427
	if (wake)
		wake_up(&state->wq);
428
	if (state->state == 0) {
429
		if (state->tree) {
430
			rb_erase(&state->rb_node, &tree->state);
431
			state->tree = NULL;
432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455
			free_extent_state(state);
		} else {
			WARN_ON(1);
		}
	} else {
		merge_state(tree, state);
	}
	return ret;
}

/*
 * clear some bits on a range in the tree.  This may require splitting
 * or inserting elements in the tree, so the gfp mask is used to
 * indicate which allocations or sleeping are allowed.
 *
 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
 * the given range from the tree regardless of state (ie for truncate).
 *
 * the range [start, end] is inclusive.
 *
 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
 * bits were already set, or zero if none of the bits were already set.
 */
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
456 457 458
		     int bits, int wake, int delete,
		     struct extent_state **cached_state,
		     gfp_t mask)
459 460
{
	struct extent_state *state;
461
	struct extent_state *cached;
462
	struct extent_state *prealloc = NULL;
463
	struct rb_node *next_node;
464
	struct rb_node *node;
465
	u64 last_end;
466 467
	int err;
	int set = 0;
468
	int clear = 0;
469

470 471 472 473
	if (delete)
		bits |= ~EXTENT_CTLBITS;
	bits |= EXTENT_FIRST_DELALLOC;

474 475
	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
		clear = 1;
476 477 478 479 480 481 482
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

483
	spin_lock(&tree->lock);
484 485
	if (cached_state) {
		cached = *cached_state;
486 487 488 489 490 491

		if (clear) {
			*cached_state = NULL;
			cached_state = NULL;
		}

492
		if (cached && cached->tree && cached->start == start) {
493 494
			if (clear)
				atomic_dec(&cached->refs);
495
			state = cached;
496
			goto hit_next;
497
		}
498 499
		if (clear)
			free_extent_state(cached);
500
	}
501 502 503 504
	/*
	 * this search will find the extents that end after
	 * our range starts
	 */
505
	node = tree_search(tree, start);
506 507 508
	if (!node)
		goto out;
	state = rb_entry(node, struct extent_state, rb_node);
509
hit_next:
510 511 512
	if (state->start > end)
		goto out;
	WARN_ON(state->end < start);
513
	last_end = state->end;
514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531

	/*
	 *     | ---- desired range ---- |
	 *  | state | or
	 *  | ------------- state -------------- |
	 *
	 * We need to split the extent we found, and may flip
	 * bits on second half.
	 *
	 * If the extent we found extends past our range, we
	 * just split and search again.  It'll get split again
	 * the next time though.
	 *
	 * If the extent we found is inside our range, we clear
	 * the desired bit on it.
	 */

	if (state->start < start) {
532 533
		if (!prealloc)
			prealloc = alloc_extent_state(GFP_ATOMIC);
534 535 536 537 538 539
		err = split_state(tree, state, prealloc, start);
		BUG_ON(err == -EEXIST);
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
540
			set |= clear_state_bit(tree, state, &bits, wake);
541 542 543
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
544 545 546 547 548 549 550 551 552 553
		}
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *                        | state |
	 * We need to split the extent, and clear the bit
	 * on the first half
	 */
	if (state->start <= end && state->end > end) {
554 555
		if (!prealloc)
			prealloc = alloc_extent_state(GFP_ATOMIC);
556 557 558 559
		err = split_state(tree, state, prealloc, end + 1);
		BUG_ON(err == -EEXIST);
		if (wake)
			wake_up(&state->wq);
560

561
		set |= clear_state_bit(tree, prealloc, &bits, wake);
J
Josef Bacik 已提交
562

563 564 565
		prealloc = NULL;
		goto out;
	}
566

567 568 569 570
	if (state->end < end && prealloc && !need_resched())
		next_node = rb_next(&state->rb_node);
	else
		next_node = NULL;
571

572
	set |= clear_state_bit(tree, state, &bits, wake);
573 574 575
	if (last_end == (u64)-1)
		goto out;
	start = last_end + 1;
576 577 578 579 580 581
	if (start <= end && next_node) {
		state = rb_entry(next_node, struct extent_state,
				 rb_node);
		if (state->start == start)
			goto hit_next;
	}
582 583 584
	goto search_again;

out:
585
	spin_unlock(&tree->lock);
586 587 588 589 590 591 592 593
	if (prealloc)
		free_extent_state(prealloc);

	return set;

search_again:
	if (start > end)
		goto out;
594
	spin_unlock(&tree->lock);
595 596 597 598 599 600 601
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

static int wait_on_state(struct extent_io_tree *tree,
			 struct extent_state *state)
602 603
		__releases(tree->lock)
		__acquires(tree->lock)
604 605 606
{
	DEFINE_WAIT(wait);
	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
607
	spin_unlock(&tree->lock);
608
	schedule();
609
	spin_lock(&tree->lock);
610 611 612 613 614 615 616 617 618 619 620 621 622 623
	finish_wait(&state->wq, &wait);
	return 0;
}

/*
 * waits for one or more bits to clear on a range in the state tree.
 * The range [start, end] is inclusive.
 * The tree lock is taken by this function
 */
int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
{
	struct extent_state *state;
	struct rb_node *node;

624
	spin_lock(&tree->lock);
625 626 627 628 629 630
again:
	while (1) {
		/*
		 * this search will find all the extents that end after
		 * our range starts
		 */
631
		node = tree_search(tree, start);
632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652
		if (!node)
			break;

		state = rb_entry(node, struct extent_state, rb_node);

		if (state->start > end)
			goto out;

		if (state->state & bits) {
			start = state->start;
			atomic_inc(&state->refs);
			wait_on_state(tree, state);
			free_extent_state(state);
			goto again;
		}
		start = state->end + 1;

		if (start > end)
			break;

		if (need_resched()) {
653
			spin_unlock(&tree->lock);
654
			cond_resched();
655
			spin_lock(&tree->lock);
656 657 658
		}
	}
out:
659
	spin_unlock(&tree->lock);
660 661 662
	return 0;
}

J
Josef Bacik 已提交
663
static int set_state_bits(struct extent_io_tree *tree,
664
			   struct extent_state *state,
665
			   int *bits)
666
{
J
Josef Bacik 已提交
667
	int ret;
668
	int bits_to_set = *bits & ~EXTENT_CTLBITS;
J
Josef Bacik 已提交
669 670 671 672

	ret = set_state_cb(tree, state, bits);
	if (ret)
		return ret;
673
	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
674 675 676
		u64 range = state->end - state->start + 1;
		tree->dirty_bytes += range;
	}
677
	state->state |= bits_to_set;
J
Josef Bacik 已提交
678 679

	return 0;
680 681
}

682 683 684 685 686 687 688 689 690 691 692
static void cache_state(struct extent_state *state,
			struct extent_state **cached_ptr)
{
	if (cached_ptr && !(*cached_ptr)) {
		if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
			*cached_ptr = state;
			atomic_inc(&state->refs);
		}
	}
}

693 694 695 696
static void uncache_state(struct extent_state **cached_ptr)
{
	if (cached_ptr && (*cached_ptr)) {
		struct extent_state *state = *cached_ptr;
697 698
		*cached_ptr = NULL;
		free_extent_state(state);
699 700 701
	}
}

702
/*
703 704
 * set some bits on a range in the tree.  This may require allocations or
 * sleeping, so the gfp mask is used to indicate what is allowed.
705
 *
706 707 708
 * If any of the exclusive bits are set, this will fail with -EEXIST if some
 * part of the range already has the desired bits set.  The start of the
 * existing range is returned in failed_start in this case.
709
 *
710
 * [start, end] is inclusive This takes the tree lock.
711
 */
712

713 714 715
int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
		   int bits, int exclusive_bits, u64 *failed_start,
		   struct extent_state **cached_state, gfp_t mask)
716 717 718 719 720 721 722
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
	int err = 0;
	u64 last_start;
	u64 last_end;
723

724
	bits |= EXTENT_FIRST_DELALLOC;
725 726 727 728 729 730 731
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

732
	spin_lock(&tree->lock);
733 734 735 736 737 738 739
	if (cached_state && *cached_state) {
		state = *cached_state;
		if (state->start == start && state->tree) {
			node = &state->rb_node;
			goto hit_next;
		}
	}
740 741 742 743
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
744
	node = tree_search(tree, start);
745
	if (!node) {
746
		err = insert_state(tree, prealloc, start, end, &bits);
747 748 749 750 751
		prealloc = NULL;
		BUG_ON(err == -EEXIST);
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
752
hit_next:
753 754 755 756 757 758 759 760 761 762
	last_start = state->start;
	last_end = state->end;

	/*
	 * | ---- desired range ---- |
	 * | state |
	 *
	 * Just lock what we found and keep going
	 */
	if (state->start == start && state->end <= end) {
C
Chris Mason 已提交
763
		struct rb_node *next_node;
764
		if (state->state & exclusive_bits) {
765 766 767 768
			*failed_start = state->start;
			err = -EEXIST;
			goto out;
		}
769

770
		err = set_state_bits(tree, state, &bits);
J
Josef Bacik 已提交
771 772 773
		if (err)
			goto out;

774
		cache_state(state, cached_state);
775
		merge_state(tree, state);
776 777
		if (last_end == (u64)-1)
			goto out;
C
Chris Mason 已提交
778

779
		start = last_end + 1;
C
Chris Mason 已提交
780 781 782 783 784 785 786 787 788
		if (start < end && prealloc && !need_resched()) {
			next_node = rb_next(node);
			if (next_node) {
				state = rb_entry(next_node, struct extent_state,
						 rb_node);
				if (state->start == start)
					goto hit_next;
			}
		}
789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808
		goto search_again;
	}

	/*
	 *     | ---- desired range ---- |
	 * | state |
	 *   or
	 * | ------------- state -------------- |
	 *
	 * We need to split the extent we found, and may flip bits on
	 * second half.
	 *
	 * If the extent we found extends past our
	 * range, we just split and search again.  It'll get split
	 * again the next time though.
	 *
	 * If the extent we found is inside our range, we set the
	 * desired bit on it.
	 */
	if (state->start < start) {
809
		if (state->state & exclusive_bits) {
810 811 812 813 814 815 816 817 818 819
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
		err = split_state(tree, state, prealloc, start);
		BUG_ON(err == -EEXIST);
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
820
			err = set_state_bits(tree, state, &bits);
J
Josef Bacik 已提交
821 822
			if (err)
				goto out;
823
			cache_state(state, cached_state);
824
			merge_state(tree, state);
825 826 827
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
828 829 830 831 832 833 834 835 836 837 838 839 840 841 842
		}
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *     | state | or               | state |
	 *
	 * There's a hole, we need to insert something in it and
	 * ignore the extent we found.
	 */
	if (state->start > start) {
		u64 this_end;
		if (end < last_start)
			this_end = end;
		else
C
Chris Mason 已提交
843
			this_end = last_start - 1;
844
		err = insert_state(tree, prealloc, start, this_end,
845
				   &bits);
846
		BUG_ON(err == -EEXIST);
J
Josef Bacik 已提交
847 848
		if (err) {
			prealloc = NULL;
849
			goto out;
J
Josef Bacik 已提交
850 851 852
		}
		cache_state(prealloc, cached_state);
		prealloc = NULL;
853 854 855 856 857 858 859 860 861 862
		start = this_end + 1;
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *                        | state |
	 * We need to split the extent, and set the bit
	 * on the first half
	 */
	if (state->start <= end && state->end > end) {
863
		if (state->state & exclusive_bits) {
864 865 866 867 868 869 870
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
		err = split_state(tree, state, prealloc, end + 1);
		BUG_ON(err == -EEXIST);

871
		err = set_state_bits(tree, prealloc, &bits);
J
Josef Bacik 已提交
872 873 874 875
		if (err) {
			prealloc = NULL;
			goto out;
		}
876
		cache_state(prealloc, cached_state);
877 878 879 880 881 882 883 884
		merge_state(tree, prealloc);
		prealloc = NULL;
		goto out;
	}

	goto search_again;

out:
885
	spin_unlock(&tree->lock);
886 887 888 889 890 891 892 893
	if (prealloc)
		free_extent_state(prealloc);

	return err;

search_again:
	if (start > end)
		goto out;
894
	spin_unlock(&tree->lock);
895 896 897 898 899 900 901 902 903 904
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

/* wrappers around set/clear extent bit */
int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
	return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
905
			      NULL, mask);
906 907 908 909 910 911
}

int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
		    int bits, gfp_t mask)
{
	return set_extent_bit(tree, start, end, bits, 0, NULL,
912
			      NULL, mask);
913 914 915 916 917
}

int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
		      int bits, gfp_t mask)
{
918
	return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
919 920 921
}

int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
922
			struct extent_state **cached_state, gfp_t mask)
923 924
{
	return set_extent_bit(tree, start, end,
C
Chris Mason 已提交
925
			      EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
926
			      0, NULL, cached_state, mask);
927 928 929 930 931 932
}

int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		       gfp_t mask)
{
	return clear_extent_bit(tree, start, end,
933
				EXTENT_DIRTY | EXTENT_DELALLOC |
934
				EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
935 936 937 938 939 940
}

int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
	return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
941
			      NULL, mask);
942 943
}

944
static int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
945 946
		       gfp_t mask)
{
947 948
	return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0,
				NULL, mask);
949 950 951
}

int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
952
			struct extent_state **cached_state, gfp_t mask)
953
{
954 955
	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
			      NULL, cached_state, mask);
956 957
}

C
Chris Mason 已提交
958
static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
959 960
				 u64 end, struct extent_state **cached_state,
				 gfp_t mask)
961
{
962
	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
963
				cached_state, mask);
964 965 966 967 968 969 970
}

int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
{
	return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
}

C
Chris Mason 已提交
971 972 973 974
/*
 * either insert or lock state struct between start and end use mask to tell
 * us if waiting is desired.
 */
975
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
976
		     int bits, struct extent_state **cached_state, gfp_t mask)
977 978 979 980
{
	int err;
	u64 failed_start;
	while (1) {
981
		err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
982 983
				     EXTENT_LOCKED, &failed_start,
				     cached_state, mask);
984 985 986 987 988 989 990 991 992 993 994
		if (err == -EEXIST && (mask & __GFP_WAIT)) {
			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
			start = failed_start;
		} else {
			break;
		}
		WARN_ON(start > end);
	}
	return err;
}

995 996
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
{
997
	return lock_extent_bits(tree, start, end, 0, NULL, mask);
998 999
}

1000 1001 1002 1003 1004 1005
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
		    gfp_t mask)
{
	int err;
	u64 failed_start;

1006 1007
	err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
			     &failed_start, NULL, mask);
Y
Yan Zheng 已提交
1008 1009 1010
	if (err == -EEXIST) {
		if (failed_start > start)
			clear_extent_bit(tree, start, failed_start - 1,
1011
					 EXTENT_LOCKED, 1, 0, NULL, mask);
1012
		return 0;
Y
Yan Zheng 已提交
1013
	}
1014 1015 1016
	return 1;
}

1017 1018 1019 1020 1021 1022 1023
int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
			 struct extent_state **cached, gfp_t mask)
{
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
				mask);
}

1024
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1025
{
1026 1027
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
				mask);
1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
}

/*
 * helper function to set pages and extents in the tree dirty
 */
int set_range_dirty(struct extent_io_tree *tree, u64 start, u64 end)
{
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	struct page *page;

	while (index <= end_index) {
		page = find_get_page(tree->mapping, index);
		BUG_ON(!page);
		__set_page_dirty_nobuffers(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

/*
 * helper function to set both pages and extents in the tree writeback
 */
1052
static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067
{
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	struct page *page;

	while (index <= end_index) {
		page = find_get_page(tree->mapping, index);
		BUG_ON(!page);
		set_page_writeback(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

C
Chris Mason 已提交
1068 1069 1070 1071 1072 1073 1074
/*
 * find the first offset in the io tree with 'bits' set. zero is
 * returned if we find something, and *start_ret and *end_ret are
 * set to reflect the state struct that was found.
 *
 * If nothing was found, 1 is returned, < 0 on error
 */
1075 1076 1077 1078 1079 1080 1081
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
			  u64 *start_ret, u64 *end_ret, int bits)
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 1;

1082
	spin_lock(&tree->lock);
1083 1084 1085 1086
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1087
	node = tree_search(tree, start);
C
Chris Mason 已提交
1088
	if (!node)
1089 1090
		goto out;

C
Chris Mason 已提交
1091
	while (1) {
1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->end >= start && (state->state & bits)) {
			*start_ret = state->start;
			*end_ret = state->end;
			ret = 0;
			break;
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1104
	spin_unlock(&tree->lock);
1105 1106 1107
	return ret;
}

C
Chris Mason 已提交
1108 1109 1110 1111
/* find the first state struct with 'bits' set after 'start', and
 * return it.  tree->lock must be held.  NULL will returned if
 * nothing was found after 'start'
 */
C
Chris Mason 已提交
1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122
struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
						 u64 start, int bits)
{
	struct rb_node *node;
	struct extent_state *state;

	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
	node = tree_search(tree, start);
C
Chris Mason 已提交
1123
	if (!node)
C
Chris Mason 已提交
1124 1125
		goto out;

C
Chris Mason 已提交
1126
	while (1) {
C
Chris Mason 已提交
1127
		state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
1128
		if (state->end >= start && (state->state & bits))
C
Chris Mason 已提交
1129
			return state;
C
Chris Mason 已提交
1130

C
Chris Mason 已提交
1131 1132 1133 1134 1135 1136 1137 1138
		node = rb_next(node);
		if (!node)
			break;
	}
out:
	return NULL;
}

C
Chris Mason 已提交
1139 1140 1141 1142 1143 1144
/*
 * find a contiguous range of bytes in the file marked as delalloc, not
 * more than 'max_bytes'.  start and end are used to return the range,
 *
 * 1 is returned if we find something, 0 if nothing was in the tree
 */
C
Chris Mason 已提交
1145
static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1146 1147
					u64 *start, u64 *end, u64 max_bytes,
					struct extent_state **cached_state)
1148 1149 1150 1151 1152 1153 1154
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 found = 0;
	u64 total_bytes = 0;

1155
	spin_lock(&tree->lock);
C
Chris Mason 已提交
1156

1157 1158 1159 1160
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1161
	node = tree_search(tree, cur_start);
1162
	if (!node) {
1163 1164
		if (!found)
			*end = (u64)-1;
1165 1166 1167
		goto out;
	}

C
Chris Mason 已提交
1168
	while (1) {
1169
		state = rb_entry(node, struct extent_state, rb_node);
1170 1171
		if (found && (state->start != cur_start ||
			      (state->state & EXTENT_BOUNDARY))) {
1172 1173 1174 1175 1176 1177 1178
			goto out;
		}
		if (!(state->state & EXTENT_DELALLOC)) {
			if (!found)
				*end = state->end;
			goto out;
		}
1179
		if (!found) {
1180
			*start = state->start;
1181 1182 1183
			*cached_state = state;
			atomic_inc(&state->refs);
		}
1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194
		found++;
		*end = state->end;
		cur_start = state->end + 1;
		node = rb_next(node);
		if (!node)
			break;
		total_bytes += state->end - state->start + 1;
		if (total_bytes >= max_bytes)
			break;
	}
out:
1195
	spin_unlock(&tree->lock);
1196 1197 1198
	return found;
}

C
Chris Mason 已提交
1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212
static noinline int __unlock_for_delalloc(struct inode *inode,
					  struct page *locked_page,
					  u64 start, u64 end)
{
	int ret;
	struct page *pages[16];
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	unsigned long nr_pages = end_index - index + 1;
	int i;

	if (index == locked_page->index && end_index == index)
		return 0;

C
Chris Mason 已提交
1213
	while (nr_pages > 0) {
C
Chris Mason 已提交
1214
		ret = find_get_pages_contig(inode->i_mapping, index,
1215 1216
				     min_t(unsigned long, nr_pages,
				     ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
		for (i = 0; i < ret; i++) {
			if (pages[i] != locked_page)
				unlock_page(pages[i]);
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

static noinline int lock_delalloc_pages(struct inode *inode,
					struct page *locked_page,
					u64 delalloc_start,
					u64 delalloc_end)
{
	unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
	unsigned long start_index = index;
	unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
	unsigned long pages_locked = 0;
	struct page *pages[16];
	unsigned long nrpages;
	int ret;
	int i;

	/* the caller is responsible for locking the start index */
	if (index == locked_page->index && index == end_index)
		return 0;

	/* skip the page at the start index */
	nrpages = end_index - index + 1;
C
Chris Mason 已提交
1249
	while (nrpages > 0) {
C
Chris Mason 已提交
1250
		ret = find_get_pages_contig(inode->i_mapping, index,
1251 1252
				     min_t(unsigned long,
				     nrpages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1253 1254 1255 1256 1257 1258 1259 1260 1261 1262
		if (ret == 0) {
			ret = -EAGAIN;
			goto done;
		}
		/* now we have an array of pages, lock them all */
		for (i = 0; i < ret; i++) {
			/*
			 * the caller is taking responsibility for
			 * locked_page
			 */
1263
			if (pages[i] != locked_page) {
C
Chris Mason 已提交
1264
				lock_page(pages[i]);
1265 1266
				if (!PageDirty(pages[i]) ||
				    pages[i]->mapping != inode->i_mapping) {
1267 1268 1269 1270 1271 1272
					ret = -EAGAIN;
					unlock_page(pages[i]);
					page_cache_release(pages[i]);
					goto done;
				}
			}
C
Chris Mason 已提交
1273
			page_cache_release(pages[i]);
1274
			pages_locked++;
C
Chris Mason 已提交
1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305
		}
		nrpages -= ret;
		index += ret;
		cond_resched();
	}
	ret = 0;
done:
	if (ret && pages_locked) {
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start,
			      ((u64)(start_index + pages_locked - 1)) <<
			      PAGE_CACHE_SHIFT);
	}
	return ret;
}

/*
 * find a contiguous range of bytes in the file marked as delalloc, not
 * more than 'max_bytes'.  start and end are used to return the range,
 *
 * 1 is returned if we find something, 0 if nothing was in the tree
 */
static noinline u64 find_lock_delalloc_range(struct inode *inode,
					     struct extent_io_tree *tree,
					     struct page *locked_page,
					     u64 *start, u64 *end,
					     u64 max_bytes)
{
	u64 delalloc_start;
	u64 delalloc_end;
	u64 found;
1306
	struct extent_state *cached_state = NULL;
C
Chris Mason 已提交
1307 1308 1309 1310 1311 1312 1313 1314
	int ret;
	int loops = 0;

again:
	/* step one, find a bunch of delalloc bytes starting at start */
	delalloc_start = *start;
	delalloc_end = 0;
	found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1315
				    max_bytes, &cached_state);
C
Chris Mason 已提交
1316
	if (!found || delalloc_end <= *start) {
C
Chris Mason 已提交
1317 1318
		*start = delalloc_start;
		*end = delalloc_end;
1319
		free_extent_state(cached_state);
C
Chris Mason 已提交
1320 1321 1322
		return found;
	}

C
Chris Mason 已提交
1323 1324 1325 1326 1327
	/*
	 * start comes from the offset of locked_page.  We have to lock
	 * pages in order, so we can't process delalloc bytes before
	 * locked_page
	 */
C
Chris Mason 已提交
1328
	if (delalloc_start < *start)
C
Chris Mason 已提交
1329 1330
		delalloc_start = *start;

C
Chris Mason 已提交
1331 1332 1333 1334
	/*
	 * make sure to limit the number of pages we try to lock down
	 * if we're looping.
	 */
C
Chris Mason 已提交
1335
	if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1336
		delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
C
Chris Mason 已提交
1337

C
Chris Mason 已提交
1338 1339 1340 1341 1342 1343 1344
	/* step two, lock all the pages after the page that has start */
	ret = lock_delalloc_pages(inode, locked_page,
				  delalloc_start, delalloc_end);
	if (ret == -EAGAIN) {
		/* some of the pages are gone, lets avoid looping by
		 * shortening the size of the delalloc range we're searching
		 */
1345
		free_extent_state(cached_state);
C
Chris Mason 已提交
1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358
		if (!loops) {
			unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
			max_bytes = PAGE_CACHE_SIZE - offset;
			loops = 1;
			goto again;
		} else {
			found = 0;
			goto out_failed;
		}
	}
	BUG_ON(ret);

	/* step three, lock the state bits for the whole range */
1359 1360
	lock_extent_bits(tree, delalloc_start, delalloc_end,
			 0, &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1361 1362 1363

	/* then test to make sure it is all still delalloc */
	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1364
			     EXTENT_DELALLOC, 1, cached_state);
C
Chris Mason 已提交
1365
	if (!ret) {
1366 1367
		unlock_extent_cached(tree, delalloc_start, delalloc_end,
				     &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1368 1369 1370 1371 1372
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start, delalloc_end);
		cond_resched();
		goto again;
	}
1373
	free_extent_state(cached_state);
C
Chris Mason 已提交
1374 1375 1376 1377 1378 1379 1380 1381 1382
	*start = delalloc_start;
	*end = delalloc_end;
out_failed:
	return found;
}

int extent_clear_unlock_delalloc(struct inode *inode,
				struct extent_io_tree *tree,
				u64 start, u64 end, struct page *locked_page,
1383
				unsigned long op)
C
Chris Mason 已提交
1384 1385 1386 1387 1388 1389 1390
{
	int ret;
	struct page *pages[16];
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	unsigned long nr_pages = end_index - index + 1;
	int i;
1391
	int clear_bits = 0;
C
Chris Mason 已提交
1392

1393
	if (op & EXTENT_CLEAR_UNLOCK)
1394
		clear_bits |= EXTENT_LOCKED;
1395
	if (op & EXTENT_CLEAR_DIRTY)
C
Chris Mason 已提交
1396 1397
		clear_bits |= EXTENT_DIRTY;

1398
	if (op & EXTENT_CLEAR_DELALLOC)
1399 1400
		clear_bits |= EXTENT_DELALLOC;

1401
	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1402 1403 1404
	if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
		    EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
		    EXTENT_SET_PRIVATE2)))
1405
		return 0;
C
Chris Mason 已提交
1406

C
Chris Mason 已提交
1407
	while (nr_pages > 0) {
C
Chris Mason 已提交
1408
		ret = find_get_pages_contig(inode->i_mapping, index,
1409 1410
				     min_t(unsigned long,
				     nr_pages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1411
		for (i = 0; i < ret; i++) {
1412

1413
			if (op & EXTENT_SET_PRIVATE2)
1414 1415
				SetPagePrivate2(pages[i]);

C
Chris Mason 已提交
1416 1417 1418 1419
			if (pages[i] == locked_page) {
				page_cache_release(pages[i]);
				continue;
			}
1420
			if (op & EXTENT_CLEAR_DIRTY)
C
Chris Mason 已提交
1421
				clear_page_dirty_for_io(pages[i]);
1422
			if (op & EXTENT_SET_WRITEBACK)
C
Chris Mason 已提交
1423
				set_page_writeback(pages[i]);
1424
			if (op & EXTENT_END_WRITEBACK)
C
Chris Mason 已提交
1425
				end_page_writeback(pages[i]);
1426
			if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1427
				unlock_page(pages[i]);
C
Chris Mason 已提交
1428 1429 1430 1431 1432 1433 1434 1435 1436
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

C
Chris Mason 已提交
1437 1438 1439 1440 1441
/*
 * count the number of bytes in the tree that have a given bit(s)
 * set.  This can be fairly slow, except for EXTENT_DIRTY which is
 * cached.  The total number found is returned.
 */
1442 1443
u64 count_range_bits(struct extent_io_tree *tree,
		     u64 *start, u64 search_end, u64 max_bytes,
1444
		     unsigned long bits, int contig)
1445 1446 1447 1448 1449
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 total_bytes = 0;
1450
	u64 last = 0;
1451 1452 1453 1454 1455 1456 1457
	int found = 0;

	if (search_end <= cur_start) {
		WARN_ON(1);
		return 0;
	}

1458
	spin_lock(&tree->lock);
1459 1460 1461 1462 1463 1464 1465 1466
	if (cur_start == 0 && bits == EXTENT_DIRTY) {
		total_bytes = tree->dirty_bytes;
		goto out;
	}
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1467
	node = tree_search(tree, cur_start);
C
Chris Mason 已提交
1468
	if (!node)
1469 1470
		goto out;

C
Chris Mason 已提交
1471
	while (1) {
1472 1473 1474
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->start > search_end)
			break;
1475 1476 1477
		if (contig && found && state->start > last + 1)
			break;
		if (state->end >= cur_start && (state->state & bits) == bits) {
1478 1479 1480 1481 1482 1483 1484 1485
			total_bytes += min(search_end, state->end) + 1 -
				       max(cur_start, state->start);
			if (total_bytes >= max_bytes)
				break;
			if (!found) {
				*start = state->start;
				found = 1;
			}
1486 1487 1488
			last = state->end;
		} else if (contig && found) {
			break;
1489 1490 1491 1492 1493 1494
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1495
	spin_unlock(&tree->lock);
1496 1497
	return total_bytes;
}
1498

C
Chris Mason 已提交
1499 1500 1501 1502
/*
 * set the private field for a given byte offset in the tree.  If there isn't
 * an extent_state there already, this does nothing.
 */
1503 1504 1505 1506 1507 1508
int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1509
	spin_lock(&tree->lock);
1510 1511 1512 1513
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1514
	node = tree_search(tree, start);
1515
	if (!node) {
1516 1517 1518 1519 1520 1521 1522 1523 1524 1525
		ret = -ENOENT;
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
	if (state->start != start) {
		ret = -ENOENT;
		goto out;
	}
	state->private = private;
out:
1526
	spin_unlock(&tree->lock);
1527 1528 1529 1530 1531 1532 1533 1534 1535
	return ret;
}

int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1536
	spin_lock(&tree->lock);
1537 1538 1539 1540
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1541
	node = tree_search(tree, start);
1542
	if (!node) {
1543 1544 1545 1546 1547 1548 1549 1550 1551 1552
		ret = -ENOENT;
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
	if (state->start != start) {
		ret = -ENOENT;
		goto out;
	}
	*private = state->private;
out:
1553
	spin_unlock(&tree->lock);
1554 1555 1556 1557 1558
	return ret;
}

/*
 * searches a range in the state tree for a given mask.
1559
 * If 'filled' == 1, this returns 1 only if every extent in the tree
1560 1561 1562 1563
 * has the bits set.  Otherwise, 1 is returned if any bit in the
 * range is found set.
 */
int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1564
		   int bits, int filled, struct extent_state *cached)
1565 1566 1567 1568 1569
{
	struct extent_state *state = NULL;
	struct rb_node *node;
	int bitset = 0;

1570
	spin_lock(&tree->lock);
1571 1572 1573 1574
	if (cached && cached->tree && cached->start == start)
		node = &cached->rb_node;
	else
		node = tree_search(tree, start);
1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593
	while (node && start <= end) {
		state = rb_entry(node, struct extent_state, rb_node);

		if (filled && state->start > start) {
			bitset = 0;
			break;
		}

		if (state->start > end)
			break;

		if (state->state & bits) {
			bitset = 1;
			if (!filled)
				break;
		} else if (filled) {
			bitset = 0;
			break;
		}
1594 1595 1596 1597

		if (state->end == (u64)-1)
			break;

1598 1599 1600 1601 1602 1603 1604 1605 1606 1607
		start = state->end + 1;
		if (start > end)
			break;
		node = rb_next(node);
		if (!node) {
			if (filled)
				bitset = 0;
			break;
		}
	}
1608
	spin_unlock(&tree->lock);
1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620
	return bitset;
}

/*
 * helper function to set a given page up to date if all the
 * extents in the tree for that page are up to date
 */
static int check_page_uptodate(struct extent_io_tree *tree,
			       struct page *page)
{
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
1621
	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634
		SetPageUptodate(page);
	return 0;
}

/*
 * helper function to unlock a page if all the extents in the tree
 * for that page are unlocked
 */
static int check_page_locked(struct extent_io_tree *tree,
			     struct page *page)
{
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
1635
	if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646
		unlock_page(page);
	return 0;
}

/*
 * helper function to end page writeback if all the extents
 * in the tree for that page are done with writeback
 */
static int check_page_writeback(struct extent_io_tree *tree,
			     struct page *page)
{
1647
	end_page_writeback(page);
1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
	return 0;
}

/* lots and lots of room for performance fixes in the end_bio funcs */

/*
 * after a writepage IO is done, we need to:
 * clear the uptodate bits on error
 * clear the writeback bits in the extent tree for this IO
 * end_page_writeback if the page has no more pending IO
 *
 * Scheduling is not allowed, so the extent state tree is expected
 * to have one and only one object corresponding to this IO.
 */
static void end_bio_extent_writepage(struct bio *bio, int err)
{
1664
	int uptodate = err == 0;
1665
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1666
	struct extent_io_tree *tree;
1667 1668 1669
	u64 start;
	u64 end;
	int whole_page;
1670
	int ret;
1671 1672 1673

	do {
		struct page *page = bvec->bv_page;
1674 1675
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686
		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
			 bvec->bv_offset;
		end = start + bvec->bv_len - 1;

		if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
			whole_page = 1;
		else
			whole_page = 0;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);
1687 1688
		if (tree->ops && tree->ops->writepage_end_io_hook) {
			ret = tree->ops->writepage_end_io_hook(page, start,
1689
						       end, NULL, uptodate);
1690 1691 1692 1693 1694 1695 1696
			if (ret)
				uptodate = 0;
		}

		if (!uptodate && tree->ops &&
		    tree->ops->writepage_io_failed_hook) {
			ret = tree->ops->writepage_io_failed_hook(bio, page,
1697
							 start, end, NULL);
1698 1699 1700 1701 1702 1703
			if (ret == 0) {
				uptodate = (err == 0);
				continue;
			}
		}

1704
		if (!uptodate) {
1705
			clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1706 1707 1708
			ClearPageUptodate(page);
			SetPageError(page);
		}
1709

1710 1711 1712 1713 1714
		if (whole_page)
			end_page_writeback(page);
		else
			check_page_writeback(tree, page);
	} while (bvec >= bio->bi_io_vec);
1715

1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732
	bio_put(bio);
}

/*
 * after a readpage IO is done, we need to:
 * clear the uptodate bits on error
 * set the uptodate bits if things worked
 * set the page up to date if all extents in the tree are uptodate
 * clear the lock bit in the extent tree
 * unlock the page if there are no other extents locked for it
 *
 * Scheduling is not allowed, so the extent state tree is expected
 * to have one and only one object corresponding to this IO.
 */
static void end_bio_extent_readpage(struct bio *bio, int err)
{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1733 1734
	struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
	struct bio_vec *bvec = bio->bi_io_vec;
1735
	struct extent_io_tree *tree;
1736 1737 1738 1739 1740
	u64 start;
	u64 end;
	int whole_page;
	int ret;

1741 1742 1743
	if (err)
		uptodate = 0;

1744 1745
	do {
		struct page *page = bvec->bv_page;
1746 1747 1748
		struct extent_state *cached = NULL;
		struct extent_state *state;

1749 1750
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1751 1752 1753 1754 1755 1756 1757 1758 1759
		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
			bvec->bv_offset;
		end = start + bvec->bv_len - 1;

		if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
			whole_page = 1;
		else
			whole_page = 0;

1760
		if (++bvec <= bvec_end)
1761 1762
			prefetchw(&bvec->bv_page->flags);

1763
		spin_lock(&tree->lock);
1764
		state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
1765
		if (state && state->start == start) {
1766 1767 1768 1769 1770 1771 1772 1773
			/*
			 * take a reference on the state, unlock will drop
			 * the ref
			 */
			cache_state(state, &cached);
		}
		spin_unlock(&tree->lock);

1774
		if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1775
			ret = tree->ops->readpage_end_io_hook(page, start, end,
1776
							      state);
1777 1778 1779
			if (ret)
				uptodate = 0;
		}
1780 1781 1782
		if (!uptodate && tree->ops &&
		    tree->ops->readpage_io_failed_hook) {
			ret = tree->ops->readpage_io_failed_hook(bio, page,
1783
							 start, end, NULL);
1784
			if (ret == 0) {
1785 1786
				uptodate =
					test_bit(BIO_UPTODATE, &bio->bi_flags);
1787 1788
				if (err)
					uptodate = 0;
1789
				uncache_state(&cached);
1790 1791 1792
				continue;
			}
		}
1793

1794
		if (uptodate) {
1795
			set_extent_uptodate(tree, start, end, &cached,
1796
					    GFP_ATOMIC);
1797
		}
1798
		unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1799

1800 1801 1802 1803 1804 1805 1806
		if (whole_page) {
			if (uptodate) {
				SetPageUptodate(page);
			} else {
				ClearPageUptodate(page);
				SetPageError(page);
			}
1807
			unlock_page(page);
1808 1809 1810 1811 1812 1813 1814
		} else {
			if (uptodate) {
				check_page_uptodate(tree, page);
			} else {
				ClearPageUptodate(page);
				SetPageError(page);
			}
1815
			check_page_locked(tree, page);
1816
		}
1817
	} while (bvec <= bvec_end);
1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830

	bio_put(bio);
}

/*
 * IO done from prepare_write is pretty simple, we just unlock
 * the structs in the extent tree when done, and set the uptodate bits
 * as appropriate.
 */
static void end_bio_extent_preparewrite(struct bio *bio, int err)
{
	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1831
	struct extent_io_tree *tree;
1832 1833 1834 1835 1836
	u64 start;
	u64 end;

	do {
		struct page *page = bvec->bv_page;
1837
		struct extent_state *cached = NULL;
1838 1839
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1840 1841 1842 1843 1844 1845 1846 1847
		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
			bvec->bv_offset;
		end = start + bvec->bv_len - 1;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);

		if (uptodate) {
1848 1849
			set_extent_uptodate(tree, start, end, &cached,
					    GFP_ATOMIC);
1850 1851 1852 1853 1854
		} else {
			ClearPageUptodate(page);
			SetPageError(page);
		}

1855
		unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1856 1857 1858 1859 1860 1861

	} while (bvec >= bio->bi_io_vec);

	bio_put(bio);
}

1862 1863 1864
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
		gfp_t gfp_flags)
1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875
{
	struct bio *bio;

	bio = bio_alloc(gfp_flags, nr_vecs);

	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
		while (!bio && (nr_vecs /= 2))
			bio = bio_alloc(gfp_flags, nr_vecs);
	}

	if (bio) {
1876
		bio->bi_size = 0;
1877 1878 1879 1880 1881 1882
		bio->bi_bdev = bdev;
		bio->bi_sector = first_sector;
	}
	return bio;
}

C
Chris Mason 已提交
1883 1884
static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
			  unsigned long bio_flags)
1885 1886
{
	int ret = 0;
1887 1888 1889 1890 1891 1892 1893
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
	struct page *page = bvec->bv_page;
	struct extent_io_tree *tree = bio->bi_private;
	u64 start;

	start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;

1894
	bio->bi_private = NULL;
1895 1896 1897

	bio_get(bio);

1898
	if (tree->ops && tree->ops->submit_bio_hook)
1899
		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1900
					   mirror_num, bio_flags, start);
1901 1902
	else
		submit_bio(rw, bio);
1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914
	if (bio_flagged(bio, BIO_EOPNOTSUPP))
		ret = -EOPNOTSUPP;
	bio_put(bio);
	return ret;
}

static int submit_extent_page(int rw, struct extent_io_tree *tree,
			      struct page *page, sector_t sector,
			      size_t size, unsigned long offset,
			      struct block_device *bdev,
			      struct bio **bio_ret,
			      unsigned long max_pages,
1915
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
1916 1917 1918
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
1919 1920 1921 1922
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
1923 1924 1925
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1926
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1927 1928 1929

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
1930 1931 1932 1933 1934 1935 1936
		if (old_compressed)
			contig = bio->bi_sector == sector;
		else
			contig = bio->bi_sector + (bio->bi_size >> 9) ==
				sector;

		if (prev_bio_flags != bio_flags || !contig ||
1937
		    (tree->ops && tree->ops->merge_bio_hook &&
C
Chris Mason 已提交
1938 1939 1940 1941 1942
		     tree->ops->merge_bio_hook(page, offset, page_size, bio,
					       bio_flags)) ||
		    bio_add_page(bio, page, page_size, offset) < page_size) {
			ret = submit_one_bio(rw, bio, mirror_num,
					     prev_bio_flags);
1943 1944 1945 1946 1947
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
1948 1949 1950 1951 1952
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

1953
	bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1954 1955
	if (!bio)
		return -ENOMEM;
1956

C
Chris Mason 已提交
1957
	bio_add_page(bio, page, page_size, offset);
1958 1959
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
1960

C
Chris Mason 已提交
1961
	if (bio_ret)
1962
		*bio_ret = bio;
C
Chris Mason 已提交
1963
	else
C
Chris Mason 已提交
1964
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1965 1966 1967 1968 1969 1970 1971 1972 1973

	return ret;
}

void set_page_extent_mapped(struct page *page)
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
1974
		set_page_private(page, EXTENT_PAGE_PRIVATE);
1975 1976 1977
	}
}

1978
static void set_page_extent_head(struct page *page, unsigned long len)
1979
{
C
Chris Mason 已提交
1980
	WARN_ON(!PagePrivate(page));
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991
	set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
}

/*
 * basic readpage implementation.  Locked extent state structs are inserted
 * into the tree that are removed when the IO is done (by the end_io
 * handlers)
 */
static int __extent_read_full_page(struct extent_io_tree *tree,
				   struct page *page,
				   get_extent_t *get_extent,
C
Chris Mason 已提交
1992 1993
				   struct bio **bio, int mirror_num,
				   unsigned long *bio_flags)
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
{
	struct inode *inode = page->mapping->host;
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	u64 end;
	u64 cur = start;
	u64 extent_offset;
	u64 last_byte = i_size_read(inode);
	u64 block_start;
	u64 cur_end;
	sector_t sector;
	struct extent_map *em;
	struct block_device *bdev;
2007
	struct btrfs_ordered_extent *ordered;
2008 2009 2010 2011
	int ret;
	int nr = 0;
	size_t page_offset = 0;
	size_t iosize;
C
Chris Mason 已提交
2012
	size_t disk_io_size;
2013
	size_t blocksize = inode->i_sb->s_blocksize;
C
Chris Mason 已提交
2014
	unsigned long this_bio_flag = 0;
2015 2016 2017 2018

	set_page_extent_mapped(page);

	end = page_end;
2019 2020 2021 2022 2023 2024 2025 2026 2027
	while (1) {
		lock_extent(tree, start, end, GFP_NOFS);
		ordered = btrfs_lookup_ordered_extent(inode, start);
		if (!ordered)
			break;
		unlock_extent(tree, start, end, GFP_NOFS);
		btrfs_start_ordered_extent(inode, ordered, 1);
		btrfs_put_ordered_extent(ordered);
	}
2028

C
Chris Mason 已提交
2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040
	if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
		char *userpage;
		size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);

		if (zero_offset) {
			iosize = PAGE_CACHE_SIZE - zero_offset;
			userpage = kmap_atomic(page, KM_USER0);
			memset(userpage + zero_offset, 0, iosize);
			flush_dcache_page(page);
			kunmap_atomic(userpage, KM_USER0);
		}
	}
2041 2042 2043
	while (cur <= end) {
		if (cur >= last_byte) {
			char *userpage;
2044 2045
			struct extent_state *cached = NULL;

2046 2047 2048 2049 2050 2051
			iosize = PAGE_CACHE_SIZE - page_offset;
			userpage = kmap_atomic(page, KM_USER0);
			memset(userpage + page_offset, 0, iosize);
			flush_dcache_page(page);
			kunmap_atomic(userpage, KM_USER0);
			set_extent_uptodate(tree, cur, cur + iosize - 1,
2052 2053 2054
					    &cached, GFP_NOFS);
			unlock_extent_cached(tree, cur, cur + iosize - 1,
					     &cached, GFP_NOFS);
2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067
			break;
		}
		em = get_extent(inode, page, page_offset, cur,
				end - cur + 1, 0);
		if (IS_ERR(em) || !em) {
			SetPageError(page);
			unlock_extent(tree, cur, end, GFP_NOFS);
			break;
		}
		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);

2068
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
C
Chris Mason 已提交
2069
			this_bio_flag = EXTENT_BIO_COMPRESSED;
2070 2071 2072
			extent_set_compress_type(&this_bio_flag,
						 em->compress_type);
		}
C
Chris Mason 已提交
2073

2074 2075 2076
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		cur_end = min(extent_map_end(em) - 1, end);
		iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
C
Chris Mason 已提交
2077 2078 2079 2080 2081 2082 2083
		if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
			disk_io_size = em->block_len;
			sector = em->block_start >> 9;
		} else {
			sector = (em->block_start + extent_offset) >> 9;
			disk_io_size = iosize;
		}
2084 2085
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
2086 2087
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
2088 2089 2090 2091 2092 2093
		free_extent_map(em);
		em = NULL;

		/* we've found a hole, just zero and go on */
		if (block_start == EXTENT_MAP_HOLE) {
			char *userpage;
2094 2095
			struct extent_state *cached = NULL;

2096 2097 2098 2099 2100 2101
			userpage = kmap_atomic(page, KM_USER0);
			memset(userpage + page_offset, 0, iosize);
			flush_dcache_page(page);
			kunmap_atomic(userpage, KM_USER0);

			set_extent_uptodate(tree, cur, cur + iosize - 1,
2102 2103 2104
					    &cached, GFP_NOFS);
			unlock_extent_cached(tree, cur, cur + iosize - 1,
			                     &cached, GFP_NOFS);
2105 2106 2107 2108 2109
			cur = cur + iosize;
			page_offset += iosize;
			continue;
		}
		/* the get_extent function already copied into the page */
2110 2111
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
2112
			check_page_uptodate(tree, page);
2113 2114 2115 2116 2117
			unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
			cur = cur + iosize;
			page_offset += iosize;
			continue;
		}
2118 2119 2120 2121 2122 2123 2124 2125 2126 2127
		/* we have an inline extent but it didn't get marked up
		 * to date.  Error out
		 */
		if (block_start == EXTENT_MAP_INLINE) {
			SetPageError(page);
			unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
			cur = cur + iosize;
			page_offset += iosize;
			continue;
		}
2128 2129 2130 2131 2132 2133 2134

		ret = 0;
		if (tree->ops && tree->ops->readpage_io_hook) {
			ret = tree->ops->readpage_io_hook(page, cur,
							  cur + iosize - 1);
		}
		if (!ret) {
2135 2136
			unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
			pnr -= page->index;
2137
			ret = submit_extent_page(READ, tree, page,
C
Chris Mason 已提交
2138
					 sector, disk_io_size, page_offset,
2139
					 bdev, bio, pnr,
C
Chris Mason 已提交
2140 2141 2142
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
2143
			nr++;
C
Chris Mason 已提交
2144
			*bio_flags = this_bio_flag;
2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162
		}
		if (ret)
			SetPageError(page);
		cur = cur + iosize;
		page_offset += iosize;
	}
	if (!nr) {
		if (!PageError(page))
			SetPageUptodate(page);
		unlock_page(page);
	}
	return 0;
}

int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
			    get_extent_t *get_extent)
{
	struct bio *bio = NULL;
C
Chris Mason 已提交
2163
	unsigned long bio_flags = 0;
2164 2165
	int ret;

C
Chris Mason 已提交
2166 2167
	ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
				      &bio_flags);
2168
	if (bio)
2169
		ret = submit_one_bio(READ, bio, 0, bio_flags);
2170 2171 2172
	return ret;
}

2173 2174 2175 2176 2177 2178 2179 2180 2181 2182
static noinline void update_nr_written(struct page *page,
				      struct writeback_control *wbc,
				      unsigned long nr_written)
{
	wbc->nr_to_write -= nr_written;
	if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
	    wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
		page->mapping->writeback_index = page->index + nr_written;
}

2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204
/*
 * the writepage semantics are similar to regular writepage.  extent
 * records are inserted to lock ranges in the tree, and as dirty areas
 * are found, they are marked writeback.  Then the lock bits are removed
 * and the end_io handler clears the writeback ranges
 */
static int __extent_writepage(struct page *page, struct writeback_control *wbc,
			      void *data)
{
	struct inode *inode = page->mapping->host;
	struct extent_page_data *epd = data;
	struct extent_io_tree *tree = epd->tree;
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 delalloc_start;
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	u64 end;
	u64 cur = start;
	u64 extent_offset;
	u64 last_byte = i_size_read(inode);
	u64 block_start;
	u64 iosize;
	sector_t sector;
2205
	struct extent_state *cached_state = NULL;
2206 2207 2208 2209
	struct extent_map *em;
	struct block_device *bdev;
	int ret;
	int nr = 0;
2210
	size_t pg_offset = 0;
2211 2212 2213 2214 2215
	size_t blocksize;
	loff_t i_size = i_size_read(inode);
	unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
	u64 nr_delalloc;
	u64 delalloc_end;
C
Chris Mason 已提交
2216 2217
	int page_started;
	int compressed;
2218
	int write_flags;
2219
	unsigned long nr_written = 0;
2220

2221
	if (wbc->sync_mode == WB_SYNC_ALL)
J
Jens Axboe 已提交
2222
		write_flags = WRITE_SYNC;
2223 2224 2225
	else
		write_flags = WRITE;

2226 2227
	trace___extent_writepage(page, inode, wbc);

2228
	WARN_ON(!PageLocked(page));
2229
	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2230
	if (page->index > end_index ||
2231
	   (page->index == end_index && !pg_offset)) {
2232
		page->mapping->a_ops->invalidatepage(page, 0);
2233 2234 2235 2236 2237 2238 2239 2240
		unlock_page(page);
		return 0;
	}

	if (page->index == end_index) {
		char *userpage;

		userpage = kmap_atomic(page, KM_USER0);
2241 2242
		memset(userpage + pg_offset, 0,
		       PAGE_CACHE_SIZE - pg_offset);
2243
		kunmap_atomic(userpage, KM_USER0);
2244
		flush_dcache_page(page);
2245
	}
2246
	pg_offset = 0;
2247 2248 2249 2250 2251

	set_page_extent_mapped(page);

	delalloc_start = start;
	delalloc_end = 0;
C
Chris Mason 已提交
2252
	page_started = 0;
2253
	if (!epd->extent_locked) {
2254
		u64 delalloc_to_write = 0;
2255 2256 2257 2258 2259 2260
		/*
		 * make sure the wbc mapping index is at least updated
		 * to this page.
		 */
		update_nr_written(page, wbc, 0);

C
Chris Mason 已提交
2261
		while (delalloc_end < page_end) {
2262
			nr_delalloc = find_lock_delalloc_range(inode, tree,
C
Chris Mason 已提交
2263 2264
						       page,
						       &delalloc_start,
2265 2266
						       &delalloc_end,
						       128 * 1024 * 1024);
2267 2268 2269 2270 2271 2272 2273
			if (nr_delalloc == 0) {
				delalloc_start = delalloc_end + 1;
				continue;
			}
			tree->ops->fill_delalloc(inode, page, delalloc_start,
						 delalloc_end, &page_started,
						 &nr_written);
2274 2275 2276 2277 2278 2279 2280 2281
			/*
			 * delalloc_end is already one less than the total
			 * length, so we don't subtract one from
			 * PAGE_CACHE_SIZE
			 */
			delalloc_to_write += (delalloc_end - delalloc_start +
					      PAGE_CACHE_SIZE) >>
					      PAGE_CACHE_SHIFT;
2282 2283
			delalloc_start = delalloc_end + 1;
		}
2284 2285 2286 2287 2288 2289 2290 2291
		if (wbc->nr_to_write < delalloc_to_write) {
			int thresh = 8192;

			if (delalloc_to_write < thresh * 2)
				thresh = delalloc_to_write;
			wbc->nr_to_write = min_t(u64, delalloc_to_write,
						 thresh);
		}
C
Chris Mason 已提交
2292

2293 2294 2295 2296 2297
		/* did the fill delalloc function already unlock and start
		 * the IO?
		 */
		if (page_started) {
			ret = 0;
2298 2299 2300 2301 2302 2303 2304
			/*
			 * we've unlocked the page, so we can't update
			 * the mapping's writeback index, just update
			 * nr_to_write.
			 */
			wbc->nr_to_write -= nr_written;
			goto done_unlocked;
2305
		}
C
Chris Mason 已提交
2306
	}
2307
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
2308 2309
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
2310 2311
		if (ret == -EAGAIN) {
			redirty_page_for_writepage(wbc, page);
2312
			update_nr_written(page, wbc, nr_written);
2313
			unlock_page(page);
2314
			ret = 0;
2315
			goto done_unlocked;
2316 2317 2318
		}
	}

2319 2320 2321 2322 2323
	/*
	 * we don't want to touch the inode after unlocking the page,
	 * so we update the mapping writeback index now
	 */
	update_nr_written(page, wbc, nr_written + 1);
2324

2325 2326
	end = page_end;
	if (last_byte <= start) {
2327 2328 2329
		if (tree->ops && tree->ops->writepage_end_io_hook)
			tree->ops->writepage_end_io_hook(page, start,
							 page_end, NULL, 1);
2330 2331 2332 2333 2334 2335 2336
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
		if (cur >= last_byte) {
2337 2338 2339
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, cur,
							 page_end, NULL, 1);
2340 2341
			break;
		}
2342
		em = epd->get_extent(inode, page, pg_offset, cur,
2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356
				     end - cur + 1, 1);
		if (IS_ERR(em) || !em) {
			SetPageError(page);
			break;
		}

		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
		sector = (em->block_start + extent_offset) >> 9;
		bdev = em->bdev;
		block_start = em->block_start;
C
Chris Mason 已提交
2357
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2358 2359 2360
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
2361 2362 2363 2364 2365
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
2366
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
2367 2368 2369 2370 2371 2372
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
2373 2374 2375
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
2376 2377 2378 2379 2380 2381 2382 2383 2384
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
2385
			pg_offset += iosize;
2386 2387 2388 2389
			continue;
		}
		/* leave this out until we have a page_mkwrite call */
		if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2390
				   EXTENT_DIRTY, 0, NULL)) {
2391
			cur = cur + iosize;
2392
			pg_offset += iosize;
2393 2394
			continue;
		}
C
Chris Mason 已提交
2395

2396 2397 2398 2399 2400 2401
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
2402
		if (ret) {
2403
			SetPageError(page);
2404
		} else {
2405
			unsigned long max_nr = end_index + 1;
2406

2407 2408
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
C
Chris Mason 已提交
2409 2410 2411
				printk(KERN_ERR "btrfs warning page %lu not "
				       "writeback, cur %llu end %llu\n",
				       page->index, (unsigned long long)cur,
2412 2413 2414
				       (unsigned long long)end);
			}

2415 2416 2417
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
2418 2419
						 end_bio_extent_writepage,
						 0, 0, 0);
2420 2421 2422 2423
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
2424
		pg_offset += iosize;
2425 2426 2427 2428 2429 2430 2431 2432 2433
		nr++;
	}
done:
	if (nr == 0) {
		/* make sure the mapping tag for page dirty gets cleared */
		set_page_writeback(page);
		end_page_writeback(page);
	}
	unlock_page(page);
2434

2435 2436
done_unlocked:

2437 2438
	/* drop our reference on any cached states */
	free_extent_state(cached_state);
2439 2440 2441 2442
	return 0;
}

/**
C
Chris Mason 已提交
2443
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456
 * @mapping: address space structure to write
 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
 * @writepage: function called for each page
 * @data: data passed to writepage function
 *
 * If a page is already under I/O, write_cache_pages() skips it, even
 * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
 * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
 * and msync() need to guarantee that all the data which was dirty at the time
 * the call was made get new I/O started against them.  If wbc->sync_mode is
 * WB_SYNC_ALL then we were called for data integrity and we must wait for
 * existing IO to complete.
 */
2457
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
2458 2459
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
2460 2461
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
2462 2463 2464
{
	int ret = 0;
	int done = 0;
2465
	int nr_to_write_done = 0;
2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;

	pagevec_init(&pvec, 0);
	if (wbc->range_cyclic) {
		index = mapping->writeback_index; /* Start from prev offset */
		end = -1;
	} else {
		index = wbc->range_start >> PAGE_CACHE_SHIFT;
		end = wbc->range_end >> PAGE_CACHE_SHIFT;
		scanned = 1;
	}
retry:
2482
	while (!done && !nr_to_write_done && (index <= end) &&
2483
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
C
Chris Mason 已提交
2484 2485
			      PAGECACHE_TAG_DIRTY, min(end - index,
				  (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498
		unsigned i;

		scanned = 1;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];

			/*
			 * At this point we hold neither mapping->tree_lock nor
			 * lock on the page itself: the page may be truncated or
			 * invalidated (changing page->mapping to NULL), or even
			 * swizzled back from swapper_space to tmpfs file
			 * mapping
			 */
C
Chris Mason 已提交
2499 2500 2501 2502
			if (tree->ops && tree->ops->write_cache_pages_lock_hook)
				tree->ops->write_cache_pages_lock_hook(page);
			else
				lock_page(page);
2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514

			if (unlikely(page->mapping != mapping)) {
				unlock_page(page);
				continue;
			}

			if (!wbc->range_cyclic && page->index > end) {
				done = 1;
				unlock_page(page);
				continue;
			}

C
Chris Mason 已提交
2515
			if (wbc->sync_mode != WB_SYNC_NONE) {
2516 2517
				if (PageWriteback(page))
					flush_fn(data);
2518
				wait_on_page_writeback(page);
C
Chris Mason 已提交
2519
			}
2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532

			if (PageWriteback(page) ||
			    !clear_page_dirty_for_io(page)) {
				unlock_page(page);
				continue;
			}

			ret = (*writepage)(page, wbc, data);

			if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
				unlock_page(page);
				ret = 0;
			}
2533
			if (ret)
2534
				done = 1;
2535 2536 2537 2538 2539 2540 2541

			/*
			 * the filesystem may choose to bump up nr_to_write.
			 * We have to make sure to honor the new nr_to_write
			 * at any time
			 */
			nr_to_write_done = wbc->nr_to_write <= 0;
2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557
		}
		pagevec_release(&pvec);
		cond_resched();
	}
	if (!scanned && !done) {
		/*
		 * We hit the last page and there is more work to be done: wrap
		 * back to the start of the file
		 */
		scanned = 1;
		index = 0;
		goto retry;
	}
	return ret;
}

2558
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
2559 2560
{
	if (epd->bio) {
2561 2562 2563 2564
		if (epd->sync_io)
			submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
		else
			submit_one_bio(WRITE, epd->bio, 0, 0);
C
Chris Mason 已提交
2565 2566 2567 2568
		epd->bio = NULL;
	}
}

2569 2570 2571 2572 2573 2574
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

2575 2576 2577 2578 2579 2580 2581 2582 2583 2584
int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
			  get_extent_t *get_extent,
			  struct writeback_control *wbc)
{
	int ret;
	struct address_space *mapping = page->mapping;
	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.get_extent = get_extent,
2585
		.extent_locked = 0,
2586
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
2587 2588
	};
	struct writeback_control wbc_writepages = {
2589
		.sync_mode	= wbc->sync_mode,
2590 2591 2592 2593 2594 2595 2596 2597
		.older_than_this = NULL,
		.nr_to_write	= 64,
		.range_start	= page_offset(page) + PAGE_CACHE_SIZE,
		.range_end	= (loff_t)-1,
	};

	ret = __extent_writepage(page, wbc, &epd);

C
Chris Mason 已提交
2598
	extent_write_cache_pages(tree, mapping, &wbc_writepages,
C
Chris Mason 已提交
2599
				 __extent_writepage, &epd, flush_write_bio);
2600
	flush_epd_write_bio(&epd);
2601 2602 2603
	return ret;
}

2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
			      u64 start, u64 end, get_extent_t *get_extent,
			      int mode)
{
	int ret = 0;
	struct address_space *mapping = inode->i_mapping;
	struct page *page;
	unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
		PAGE_CACHE_SHIFT;

	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.get_extent = get_extent,
		.extent_locked = 1,
2619
		.sync_io = mode == WB_SYNC_ALL,
2620 2621 2622 2623 2624 2625 2626 2627 2628
	};
	struct writeback_control wbc_writepages = {
		.sync_mode	= mode,
		.older_than_this = NULL,
		.nr_to_write	= nr_pages * 2,
		.range_start	= start,
		.range_end	= end + 1,
	};

C
Chris Mason 已提交
2629
	while (start <= end) {
2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643
		page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
		if (clear_page_dirty_for_io(page))
			ret = __extent_writepage(page, &wbc_writepages, &epd);
		else {
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, start,
						 start + PAGE_CACHE_SIZE - 1,
						 NULL, 1);
			unlock_page(page);
		}
		page_cache_release(page);
		start += PAGE_CACHE_SIZE;
	}

2644
	flush_epd_write_bio(&epd);
2645 2646
	return ret;
}
2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657

int extent_writepages(struct extent_io_tree *tree,
		      struct address_space *mapping,
		      get_extent_t *get_extent,
		      struct writeback_control *wbc)
{
	int ret = 0;
	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.get_extent = get_extent,
2658
		.extent_locked = 0,
2659
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
2660 2661
	};

C
Chris Mason 已提交
2662
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
2663 2664
				       __extent_writepage, &epd,
				       flush_write_bio);
2665
	flush_epd_write_bio(&epd);
2666 2667 2668 2669 2670 2671 2672 2673 2674 2675
	return ret;
}

int extent_readpages(struct extent_io_tree *tree,
		     struct address_space *mapping,
		     struct list_head *pages, unsigned nr_pages,
		     get_extent_t get_extent)
{
	struct bio *bio = NULL;
	unsigned page_idx;
C
Chris Mason 已提交
2676
	unsigned long bio_flags = 0;
2677 2678 2679 2680 2681 2682

	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
		struct page *page = list_entry(pages->prev, struct page, lru);

		prefetchw(&page->flags);
		list_del(&page->lru);
2683
		if (!add_to_page_cache_lru(page, mapping,
2684
					page->index, GFP_NOFS)) {
2685
			__extent_read_full_page(tree, page, get_extent,
C
Chris Mason 已提交
2686
						&bio, 0, &bio_flags);
2687 2688 2689 2690 2691
		}
		page_cache_release(page);
	}
	BUG_ON(!list_empty(pages));
	if (bio)
C
Chris Mason 已提交
2692
		submit_one_bio(READ, bio, 0, bio_flags);
2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703
	return 0;
}

/*
 * basic invalidatepage code, this waits on any locked or writeback
 * ranges corresponding to the page, and then deletes any extent state
 * records from the tree
 */
int extent_invalidatepage(struct extent_io_tree *tree,
			  struct page *page, unsigned long offset)
{
2704
	struct extent_state *cached_state = NULL;
2705 2706 2707 2708
	u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
	u64 end = start + PAGE_CACHE_SIZE - 1;
	size_t blocksize = page->mapping->host->i_sb->s_blocksize;

C
Chris Mason 已提交
2709
	start += (offset + blocksize - 1) & ~(blocksize - 1);
2710 2711 2712
	if (start > end)
		return 0;

2713
	lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2714
	wait_on_page_writeback(page);
2715
	clear_extent_bit(tree, start, end,
2716 2717
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
2718
			 1, 1, &cached_state, GFP_NOFS);
2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768
	return 0;
}

/*
 * simple commit_write call, set_range_dirty is used to mark both
 * the pages and the extent records as dirty
 */
int extent_commit_write(struct extent_io_tree *tree,
			struct inode *inode, struct page *page,
			unsigned from, unsigned to)
{
	loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;

	set_page_extent_mapped(page);
	set_page_dirty(page);

	if (pos > inode->i_size) {
		i_size_write(inode, pos);
		mark_inode_dirty(inode);
	}
	return 0;
}

int extent_prepare_write(struct extent_io_tree *tree,
			 struct inode *inode, struct page *page,
			 unsigned from, unsigned to, get_extent_t *get_extent)
{
	u64 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
	u64 block_start;
	u64 orig_block_start;
	u64 block_end;
	u64 cur_end;
	struct extent_map *em;
	unsigned blocksize = 1 << inode->i_blkbits;
	size_t page_offset = 0;
	size_t block_off_start;
	size_t block_off_end;
	int err = 0;
	int iocount = 0;
	int ret = 0;
	int isnew;

	set_page_extent_mapped(page);

	block_start = (page_start + from) & ~((u64)blocksize - 1);
	block_end = (page_start + to - 1) | (blocksize - 1);
	orig_block_start = block_start;

	lock_extent(tree, page_start, page_end, GFP_NOFS);
C
Chris Mason 已提交
2769
	while (block_start <= block_end) {
2770 2771
		em = get_extent(inode, page, page_offset, block_start,
				block_end - block_start + 1, 1);
C
Chris Mason 已提交
2772
		if (IS_ERR(em) || !em)
2773
			goto err;
C
Chris Mason 已提交
2774

2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797
		cur_end = min(block_end, extent_map_end(em) - 1);
		block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
		block_off_end = block_off_start + blocksize;
		isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);

		if (!PageUptodate(page) && isnew &&
		    (block_off_end > to || block_off_start < from)) {
			void *kaddr;

			kaddr = kmap_atomic(page, KM_USER0);
			if (block_off_end > to)
				memset(kaddr + to, 0, block_off_end - to);
			if (block_off_start < from)
				memset(kaddr + block_off_start, 0,
				       from - block_off_start);
			flush_dcache_page(page);
			kunmap_atomic(kaddr, KM_USER0);
		}
		if ((em->block_start != EXTENT_MAP_HOLE &&
		     em->block_start != EXTENT_MAP_INLINE) &&
		    !isnew && !PageUptodate(page) &&
		    (block_off_end > to || block_off_start < from) &&
		    !test_range_bit(tree, block_start, cur_end,
2798
				    EXTENT_UPTODATE, 1, NULL)) {
2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811
			u64 sector;
			u64 extent_offset = block_start - em->start;
			size_t iosize;
			sector = (em->block_start + extent_offset) >> 9;
			iosize = (cur_end - block_start + blocksize) &
				~((u64)blocksize - 1);
			/*
			 * we've already got the extent locked, but we
			 * need to split the state such that our end_bio
			 * handler can clear the lock.
			 */
			set_extent_bit(tree, block_start,
				       block_start + iosize - 1,
2812
				       EXTENT_LOCKED, 0, NULL, NULL, GFP_NOFS);
2813 2814 2815
			ret = submit_extent_page(READ, tree, page,
					 sector, iosize, page_offset, em->bdev,
					 NULL, 1,
C
Chris Mason 已提交
2816 2817
					 end_bio_extent_preparewrite, 0,
					 0, 0);
2818 2819
			if (ret && !err)
				err = ret;
2820 2821 2822
			iocount++;
			block_start = block_start + iosize;
		} else {
2823 2824 2825
			struct extent_state *cached = NULL;

			set_extent_uptodate(tree, block_start, cur_end, &cached,
2826
					    GFP_NOFS);
2827 2828
			unlock_extent_cached(tree, block_start, cur_end,
					     &cached, GFP_NOFS);
2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843
			block_start = cur_end + 1;
		}
		page_offset = block_start & (PAGE_CACHE_SIZE - 1);
		free_extent_map(em);
	}
	if (iocount) {
		wait_extent_bit(tree, orig_block_start,
				block_end, EXTENT_LOCKED);
	}
	check_page_uptodate(tree, page);
err:
	/* FIXME, zero out newly allocated blocks on error */
	return err;
}

2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856
/*
 * a helper for releasepage, this tests for areas of the page that
 * are locked or under IO and drops the related state bits if it is safe
 * to drop the page.
 */
int try_release_extent_state(struct extent_map_tree *map,
			     struct extent_io_tree *tree, struct page *page,
			     gfp_t mask)
{
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret = 1;

2857
	if (test_range_bit(tree, start, end,
2858
			   EXTENT_IOBITS, 0, NULL))
2859 2860 2861 2862
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
2863 2864 2865 2866
		/*
		 * at this point we can safely clear everything except the
		 * locked bit and the nodatasum bit
		 */
2867
		ret = clear_extent_bit(tree, start, end,
2868 2869
				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
				 0, 0, NULL, mask);
2870 2871 2872 2873 2874 2875 2876 2877

		/* if clear_extent_bit failed for enomem reasons,
		 * we can't allow the release to continue.
		 */
		if (ret < 0)
			ret = 0;
		else
			ret = 1;
2878 2879 2880 2881
	}
	return ret;
}

2882 2883 2884 2885 2886 2887
/*
 * a helper for releasepage.  As long as there are no locked extents
 * in the range corresponding to the page, both state records and extent
 * map records are removed
 */
int try_release_extent_mapping(struct extent_map_tree *map,
2888 2889
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
2890 2891 2892 2893
{
	struct extent_map *em;
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
2894

2895 2896
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
2897
		u64 len;
2898
		while (start <= end) {
2899
			len = end - start + 1;
2900
			write_lock(&map->lock);
2901
			em = lookup_extent_mapping(map, start, len);
2902
			if (!em || IS_ERR(em)) {
2903
				write_unlock(&map->lock);
2904 2905
				break;
			}
2906 2907
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
2908
				write_unlock(&map->lock);
2909 2910 2911 2912 2913
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
2914
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
2915
					    0, NULL)) {
2916 2917 2918 2919 2920
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
2921
			write_unlock(&map->lock);
2922 2923

			/* once for us */
2924 2925 2926
			free_extent_map(em);
		}
	}
2927
	return try_release_extent_state(map, tree, page, mask);
2928 2929 2930 2931 2932 2933
}

sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
		get_extent_t *get_extent)
{
	struct inode *inode = mapping->host;
2934
	struct extent_state *cached_state = NULL;
2935 2936
	u64 start = iblock << inode->i_blkbits;
	sector_t sector = 0;
Y
Yan Zheng 已提交
2937
	size_t blksize = (1 << inode->i_blkbits);
2938 2939
	struct extent_map *em;

2940 2941
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
			 0, &cached_state, GFP_NOFS);
Y
Yan Zheng 已提交
2942
	em = get_extent(inode, NULL, 0, start, blksize, 0);
2943 2944
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start,
			     start + blksize - 1, &cached_state, GFP_NOFS);
2945 2946 2947
	if (!em || IS_ERR(em))
		return 0;

Y
Yan Zheng 已提交
2948
	if (em->block_start > EXTENT_MAP_LAST_BYTE)
2949 2950 2951 2952 2953 2954 2955 2956
		goto out;

	sector = (em->block_start + start - em->start) >> inode->i_blkbits;
out:
	free_extent_map(em);
	return sector;
}

2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996
/*
 * helper function for fiemap, which doesn't want to see any holes.
 * This maps until we find something past 'last'
 */
static struct extent_map *get_extent_skip_holes(struct inode *inode,
						u64 offset,
						u64 last,
						get_extent_t *get_extent)
{
	u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
	struct extent_map *em;
	u64 len;

	if (offset >= last)
		return NULL;

	while(1) {
		len = last - offset;
		if (len == 0)
			break;
		len = (len + sectorsize - 1) & ~(sectorsize - 1);
		em = get_extent(inode, NULL, 0, offset, len, 0);
		if (!em || IS_ERR(em))
			return em;

		/* if this isn't a hole return it */
		if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
		    em->block_start != EXTENT_MAP_HOLE) {
			return em;
		}

		/* this is a hole, advance to the next extent */
		offset = extent_map_end(em);
		free_extent_map(em);
		if (offset >= last)
			break;
	}
	return NULL;
}

Y
Yehuda Sadeh 已提交
2997 2998 2999
int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
		__u64 start, __u64 len, get_extent_t *get_extent)
{
J
Josef Bacik 已提交
3000
	int ret = 0;
Y
Yehuda Sadeh 已提交
3001 3002 3003
	u64 off = start;
	u64 max = start + len;
	u32 flags = 0;
J
Josef Bacik 已提交
3004 3005
	u32 found_type;
	u64 last;
3006
	u64 last_for_get_extent = 0;
Y
Yehuda Sadeh 已提交
3007
	u64 disko = 0;
3008
	u64 isize = i_size_read(inode);
J
Josef Bacik 已提交
3009
	struct btrfs_key found_key;
Y
Yehuda Sadeh 已提交
3010
	struct extent_map *em = NULL;
3011
	struct extent_state *cached_state = NULL;
J
Josef Bacik 已提交
3012 3013
	struct btrfs_path *path;
	struct btrfs_file_extent_item *item;
Y
Yehuda Sadeh 已提交
3014
	int end = 0;
3015 3016 3017
	u64 em_start = 0;
	u64 em_len = 0;
	u64 em_end = 0;
Y
Yehuda Sadeh 已提交
3018 3019 3020 3021 3022
	unsigned long emflags;

	if (len == 0)
		return -EINVAL;

J
Josef Bacik 已提交
3023 3024 3025 3026 3027
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->leave_spinning = 1;

3028 3029 3030 3031
	/*
	 * lookup the last file extent.  We're not using i_size here
	 * because there might be preallocation past i_size
	 */
J
Josef Bacik 已提交
3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044
	ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
				       path, inode->i_ino, -1, 0);
	if (ret < 0) {
		btrfs_free_path(path);
		return ret;
	}
	WARN_ON(!ret);
	path->slots[0]--;
	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
			      struct btrfs_file_extent_item);
	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
	found_type = btrfs_key_type(&found_key);

3045
	/* No extents, but there might be delalloc bits */
J
Josef Bacik 已提交
3046 3047
	if (found_key.objectid != inode->i_ino ||
	    found_type != BTRFS_EXTENT_DATA_KEY) {
3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058
		/* have to trust i_size as the end */
		last = (u64)-1;
		last_for_get_extent = isize;
	} else {
		/*
		 * remember the start of the last extent.  There are a
		 * bunch of different factors that go into the length of the
		 * extent, so its much less complex to remember where it started
		 */
		last = found_key.offset;
		last_for_get_extent = last + 1;
J
Josef Bacik 已提交
3059 3060 3061
	}
	btrfs_free_path(path);

3062 3063 3064 3065 3066 3067 3068 3069 3070 3071
	/*
	 * we might have some extents allocated but more delalloc past those
	 * extents.  so, we trust isize unless the start of the last extent is
	 * beyond isize
	 */
	if (last < isize) {
		last = (u64)-1;
		last_for_get_extent = isize;
	}

3072 3073
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
			 &cached_state, GFP_NOFS);
3074 3075 3076

	em = get_extent_skip_holes(inode, off, last_for_get_extent,
				   get_extent);
Y
Yehuda Sadeh 已提交
3077 3078 3079 3080 3081 3082
	if (!em)
		goto out;
	if (IS_ERR(em)) {
		ret = PTR_ERR(em);
		goto out;
	}
J
Josef Bacik 已提交
3083

Y
Yehuda Sadeh 已提交
3084
	while (!end) {
3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097
		u64 offset_in_extent;

		/* break if the extent we found is outside the range */
		if (em->start >= max || extent_map_end(em) < off)
			break;

		/*
		 * get_extent may return an extent that starts before our
		 * requested range.  We have to make sure the ranges
		 * we return to fiemap always move forward and don't
		 * overlap, so adjust the offsets here
		 */
		em_start = max(em->start, off);
Y
Yehuda Sadeh 已提交
3098

3099 3100 3101 3102 3103
		/*
		 * record the offset from the start of the extent
		 * for adjusting the disk offset below
		 */
		offset_in_extent = em_start - em->start;
3104
		em_end = extent_map_end(em);
3105
		em_len = em_end - em_start;
3106
		emflags = em->flags;
Y
Yehuda Sadeh 已提交
3107 3108 3109
		disko = 0;
		flags = 0;

3110 3111 3112 3113 3114 3115 3116
		/*
		 * bump off for our next call to get_extent
		 */
		off = extent_map_end(em);
		if (off >= max)
			end = 1;

3117
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
3118 3119
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
3120
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
3121 3122
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
3123
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
3124 3125
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
3126
		} else {
3127
			disko = em->block_start + offset_in_extent;
Y
Yehuda Sadeh 已提交
3128 3129 3130 3131 3132 3133
		}
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			flags |= FIEMAP_EXTENT_ENCODED;

		free_extent_map(em);
		em = NULL;
3134 3135
		if ((em_start >= last) || em_len == (u64)-1 ||
		   (last == (u64)-1 && isize <= em_end)) {
Y
Yehuda Sadeh 已提交
3136 3137 3138 3139
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}

3140 3141 3142 3143 3144 3145 3146 3147
		/* now scan forward to see if this is really the last extent. */
		em = get_extent_skip_holes(inode, off, last_for_get_extent,
					   get_extent);
		if (IS_ERR(em)) {
			ret = PTR_ERR(em);
			goto out;
		}
		if (!em) {
J
Josef Bacik 已提交
3148 3149 3150
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}
3151 3152 3153 3154
		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
					      em_len, flags);
		if (ret)
			goto out_free;
Y
Yehuda Sadeh 已提交
3155 3156 3157 3158
	}
out_free:
	free_extent_map(em);
out:
3159 3160
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
			     &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
3161 3162 3163
	return ret;
}

3164 3165 3166 3167 3168 3169 3170 3171 3172 3173
static inline struct page *extent_buffer_page(struct extent_buffer *eb,
					      unsigned long i)
{
	struct page *p;
	struct address_space *mapping;

	if (i == 0)
		return eb->first_page;
	i += eb->start >> PAGE_CACHE_SHIFT;
	mapping = eb->first_page->mapping;
C
Chris Mason 已提交
3174 3175
	if (!mapping)
		return NULL;
3176 3177 3178 3179 3180 3181 3182

	/*
	 * extent_buffer_page is only called after pinning the page
	 * by increasing the reference count.  So we know the page must
	 * be in the radix tree.
	 */
	rcu_read_lock();
3183
	p = radix_tree_lookup(&mapping->page_tree, i);
3184
	rcu_read_unlock();
3185

3186 3187 3188
	return p;
}

3189
static inline unsigned long num_extent_pages(u64 start, u64 len)
3190
{
3191 3192
	return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
		(start >> PAGE_CACHE_SHIFT);
3193 3194
}

3195 3196 3197 3198 3199 3200
static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
						   u64 start,
						   unsigned long len,
						   gfp_t mask)
{
	struct extent_buffer *eb = NULL;
3201
#if LEAK_DEBUG
3202
	unsigned long flags;
C
Chris Mason 已提交
3203
#endif
3204 3205

	eb = kmem_cache_zalloc(extent_buffer_cache, mask);
T
Tsutomu Itoh 已提交
3206 3207
	if (eb == NULL)
		return NULL;
3208 3209
	eb->start = start;
	eb->len = len;
3210 3211 3212
	spin_lock_init(&eb->lock);
	init_waitqueue_head(&eb->lock_wq);

3213
#if LEAK_DEBUG
3214 3215 3216
	spin_lock_irqsave(&leak_lock, flags);
	list_add(&eb->leak_list, &buffers);
	spin_unlock_irqrestore(&leak_lock, flags);
C
Chris Mason 已提交
3217
#endif
3218 3219 3220 3221 3222 3223 3224
	atomic_set(&eb->refs, 1);

	return eb;
}

static void __free_extent_buffer(struct extent_buffer *eb)
{
3225
#if LEAK_DEBUG
3226 3227 3228 3229
	unsigned long flags;
	spin_lock_irqsave(&leak_lock, flags);
	list_del(&eb->leak_list);
	spin_unlock_irqrestore(&leak_lock, flags);
C
Chris Mason 已提交
3230
#endif
3231 3232 3233
	kmem_cache_free(extent_buffer_cache, eb);
}

3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266
/*
 * Helper for releasing extent buffer page.
 */
static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
						unsigned long start_idx)
{
	unsigned long index;
	struct page *page;

	if (!eb->first_page)
		return;

	index = num_extent_pages(eb->start, eb->len);
	if (start_idx >= index)
		return;

	do {
		index--;
		page = extent_buffer_page(eb, index);
		if (page)
			page_cache_release(page);
	} while (index != start_idx);
}

/*
 * Helper for releasing the extent buffer.
 */
static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
{
	btrfs_release_extent_buffer_page(eb, 0);
	__free_extent_buffer(eb);
}

3267 3268 3269 3270 3271 3272 3273 3274 3275
struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
					  u64 start, unsigned long len,
					  struct page *page0,
					  gfp_t mask)
{
	unsigned long num_pages = num_extent_pages(start, len);
	unsigned long i;
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	struct extent_buffer *eb;
3276
	struct extent_buffer *exists = NULL;
3277 3278 3279
	struct page *p;
	struct address_space *mapping = tree->mapping;
	int uptodate = 1;
3280
	int ret;
3281

3282 3283 3284 3285
	rcu_read_lock();
	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
	if (eb && atomic_inc_not_zero(&eb->refs)) {
		rcu_read_unlock();
J
Josef Bacik 已提交
3286
		mark_page_accessed(eb->first_page);
3287 3288
		return eb;
	}
3289
	rcu_read_unlock();
3290

3291
	eb = __alloc_extent_buffer(tree, start, len, mask);
3292
	if (!eb)
3293 3294 3295 3296 3297 3298 3299 3300 3301 3302
		return NULL;

	if (page0) {
		eb->first_page = page0;
		i = 1;
		index++;
		page_cache_get(page0);
		mark_page_accessed(page0);
		set_page_extent_mapped(page0);
		set_page_extent_head(page0, len);
3303
		uptodate = PageUptodate(page0);
3304 3305 3306 3307 3308 3309 3310
	} else {
		i = 0;
	}
	for (; i < num_pages; i++, index++) {
		p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
		if (!p) {
			WARN_ON(1);
3311
			goto free_eb;
3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322
		}
		set_page_extent_mapped(p);
		mark_page_accessed(p);
		if (i == 0) {
			eb->first_page = p;
			set_page_extent_head(p, len);
		} else {
			set_page_private(p, EXTENT_PAGE_PRIVATE);
		}
		if (!PageUptodate(p))
			uptodate = 0;
C
Chris Mason 已提交
3323 3324 3325 3326 3327 3328 3329

		/*
		 * see below about how we avoid a nasty race with release page
		 * and why we unlock later
		 */
		if (i != 0)
			unlock_page(p);
3330 3331
	}
	if (uptodate)
3332
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3333

3334 3335 3336 3337
	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (ret)
		goto free_eb;

3338
	spin_lock(&tree->buffer_lock);
3339 3340 3341 3342
	ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
	if (ret == -EEXIST) {
		exists = radix_tree_lookup(&tree->buffer,
						start >> PAGE_CACHE_SHIFT);
3343 3344 3345
		/* add one reference for the caller */
		atomic_inc(&exists->refs);
		spin_unlock(&tree->buffer_lock);
3346
		radix_tree_preload_end();
3347 3348 3349 3350
		goto free_eb;
	}
	/* add one reference for the tree */
	atomic_inc(&eb->refs);
3351
	spin_unlock(&tree->buffer_lock);
3352
	radix_tree_preload_end();
C
Chris Mason 已提交
3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366

	/*
	 * there is a race where release page may have
	 * tried to find this extent buffer in the radix
	 * but failed.  It will tell the VM it is safe to
	 * reclaim the, and it will clear the page private bit.
	 * We must make sure to set the page private bit properly
	 * after the extent buffer is in the radix tree so
	 * it doesn't get lost
	 */
	set_page_extent_mapped(eb->first_page);
	set_page_extent_head(eb->first_page, eb->len);
	if (!page0)
		unlock_page(eb->first_page);
3367 3368
	return eb;

3369
free_eb:
C
Chris Mason 已提交
3370 3371 3372
	if (eb->first_page && !page0)
		unlock_page(eb->first_page);

3373
	if (!atomic_dec_and_test(&eb->refs))
3374
		return exists;
3375
	btrfs_release_extent_buffer(eb);
3376
	return exists;
3377 3378 3379 3380 3381 3382 3383 3384
}

struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
					 u64 start, unsigned long len,
					  gfp_t mask)
{
	struct extent_buffer *eb;

3385 3386 3387 3388
	rcu_read_lock();
	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
	if (eb && atomic_inc_not_zero(&eb->refs)) {
		rcu_read_unlock();
J
Josef Bacik 已提交
3389
		mark_page_accessed(eb->first_page);
3390 3391 3392
		return eb;
	}
	rcu_read_unlock();
J
Josef Bacik 已提交
3393

3394
	return NULL;
3395 3396 3397 3398 3399 3400 3401 3402 3403 3404
}

void free_extent_buffer(struct extent_buffer *eb)
{
	if (!eb)
		return;

	if (!atomic_dec_and_test(&eb->refs))
		return;

3405
	WARN_ON(1);
3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418
}

int clear_extent_buffer_dirty(struct extent_io_tree *tree,
			      struct extent_buffer *eb)
{
	unsigned long i;
	unsigned long num_pages;
	struct page *page;

	num_pages = num_extent_pages(eb->start, eb->len);

	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
3419
		if (!PageDirty(page))
C
Chris Mason 已提交
3420 3421
			continue;

3422
		lock_page(page);
C
Chris Mason 已提交
3423 3424 3425
		WARN_ON(!PagePrivate(page));

		set_page_extent_mapped(page);
3426 3427 3428 3429
		if (i == 0)
			set_page_extent_head(page, eb->len);

		clear_page_dirty_for_io(page);
3430
		spin_lock_irq(&page->mapping->tree_lock);
3431 3432 3433 3434 3435
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
3436
		spin_unlock_irq(&page->mapping->tree_lock);
3437
		unlock_page(page);
3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453
	}
	return 0;
}

int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
				    struct extent_buffer *eb)
{
	return wait_on_extent_writeback(tree, eb->start,
					eb->start + eb->len - 1);
}

int set_extent_buffer_dirty(struct extent_io_tree *tree,
			     struct extent_buffer *eb)
{
	unsigned long i;
	unsigned long num_pages;
3454
	int was_dirty = 0;
3455

3456
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3457
	num_pages = num_extent_pages(eb->start, eb->len);
3458
	for (i = 0; i < num_pages; i++)
3459
		__set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3460
	return was_dirty;
3461 3462
}

3463
int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3464 3465
				struct extent_buffer *eb,
				struct extent_state **cached_state)
3466 3467 3468 3469 3470 3471
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

	num_pages = num_extent_pages(eb->start, eb->len);
3472
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3473 3474

	clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3475
			      cached_state, GFP_NOFS);
3476 3477
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
C
Chris Mason 已提交
3478 3479
		if (page)
			ClearPageUptodate(page);
3480 3481 3482 3483
	}
	return 0;
}

3484 3485 3486 3487 3488 3489 3490 3491 3492 3493
int set_extent_buffer_uptodate(struct extent_io_tree *tree,
				struct extent_buffer *eb)
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

	num_pages = num_extent_pages(eb->start, eb->len);

	set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3494
			    NULL, GFP_NOFS);
3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
		    ((i == num_pages - 1) &&
		     ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
			check_page_uptodate(tree, page);
			continue;
		}
		SetPageUptodate(page);
	}
	return 0;
}

3508 3509 3510 3511 3512 3513 3514 3515 3516
int extent_range_uptodate(struct extent_io_tree *tree,
			  u64 start, u64 end)
{
	struct page *page;
	int ret;
	int pg_uptodate = 1;
	int uptodate;
	unsigned long index;

3517
	ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL);
3518 3519
	if (ret)
		return 1;
C
Chris Mason 已提交
3520
	while (start <= end) {
3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533
		index = start >> PAGE_CACHE_SHIFT;
		page = find_get_page(tree->mapping, index);
		uptodate = PageUptodate(page);
		page_cache_release(page);
		if (!uptodate) {
			pg_uptodate = 0;
			break;
		}
		start += PAGE_CACHE_SIZE;
	}
	return pg_uptodate;
}

3534
int extent_buffer_uptodate(struct extent_io_tree *tree,
3535 3536
			   struct extent_buffer *eb,
			   struct extent_state *cached_state)
3537
{
3538
	int ret = 0;
3539 3540
	unsigned long num_pages;
	unsigned long i;
3541 3542 3543
	struct page *page;
	int pg_uptodate = 1;

3544
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
C
Chris Mason 已提交
3545
		return 1;
3546

C
Chris Mason 已提交
3547
	ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3548
			   EXTENT_UPTODATE, 1, cached_state);
C
Chris Mason 已提交
3549 3550
	if (ret)
		return ret;
3551 3552 3553 3554 3555 3556 3557 3558 3559

	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if (!PageUptodate(page)) {
			pg_uptodate = 0;
			break;
		}
	}
C
Chris Mason 已提交
3560
	return pg_uptodate;
3561 3562 3563 3564
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
			     struct extent_buffer *eb,
3565
			     u64 start, int wait,
3566
			     get_extent_t *get_extent, int mirror_num)
3567 3568 3569 3570 3571 3572
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
3573 3574 3575
	int locked_pages = 0;
	int all_uptodate = 1;
	int inc_all_pages = 0;
3576
	unsigned long num_pages;
3577
	struct bio *bio = NULL;
C
Chris Mason 已提交
3578
	unsigned long bio_flags = 0;
3579

3580
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3581 3582
		return 0;

3583
	if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3584
			   EXTENT_UPTODATE, 1, NULL)) {
3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599
		return 0;
	}

	if (start) {
		WARN_ON(start < eb->start);
		start_i = (start >> PAGE_CACHE_SHIFT) -
			(eb->start >> PAGE_CACHE_SHIFT);
	} else {
		start_i = 0;
	}

	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if (!wait) {
3600
			if (!trylock_page(page))
3601
				goto unlock_exit;
3602 3603 3604
		} else {
			lock_page(page);
		}
3605
		locked_pages++;
C
Chris Mason 已提交
3606
		if (!PageUptodate(page))
3607 3608 3609 3610
			all_uptodate = 0;
	}
	if (all_uptodate) {
		if (start_i == 0)
3611
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3612 3613 3614 3615 3616
		goto unlock_exit;
	}

	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
C
Chris Mason 已提交
3617 3618 3619 3620 3621 3622 3623

		WARN_ON(!PagePrivate(page));

		set_page_extent_mapped(page);
		if (i == 0)
			set_page_extent_head(page, eb->len);

3624 3625 3626 3627 3628
		if (inc_all_pages)
			page_cache_get(page);
		if (!PageUptodate(page)) {
			if (start_i == 0)
				inc_all_pages = 1;
3629
			ClearPageError(page);
3630
			err = __extent_read_full_page(tree, page,
3631
						      get_extent, &bio,
C
Chris Mason 已提交
3632
						      mirror_num, &bio_flags);
C
Chris Mason 已提交
3633
			if (err)
3634 3635 3636 3637 3638 3639
				ret = err;
		} else {
			unlock_page(page);
		}
	}

3640
	if (bio)
C
Chris Mason 已提交
3641
		submit_one_bio(READ, bio, mirror_num, bio_flags);
3642

C
Chris Mason 已提交
3643
	if (ret || !wait)
3644
		return ret;
C
Chris Mason 已提交
3645

3646 3647 3648
	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		wait_on_page_locked(page);
C
Chris Mason 已提交
3649
		if (!PageUptodate(page))
3650 3651
			ret = -EIO;
	}
C
Chris Mason 已提交
3652

3653
	if (!ret)
3654
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3655
	return ret;
3656 3657 3658

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
3659
	while (locked_pages > 0) {
3660 3661 3662 3663 3664 3665
		page = extent_buffer_page(eb, i);
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684
}

void read_extent_buffer(struct extent_buffer *eb, void *dstv,
			unsigned long start,
			unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	char *dst = (char *)dstv;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);

C
Chris Mason 已提交
3685
	while (len > 0) {
3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722
		page = extent_buffer_page(eb, i);

		cur = min(len, (PAGE_CACHE_SIZE - offset));
		kaddr = kmap_atomic(page, KM_USER1);
		memcpy(dst, kaddr + offset, cur);
		kunmap_atomic(kaddr, KM_USER1);

		dst += cur;
		len -= cur;
		offset = 0;
		i++;
	}
}

int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
			       unsigned long min_len, char **token, char **map,
			       unsigned long *map_start,
			       unsigned long *map_len, int km)
{
	size_t offset = start & (PAGE_CACHE_SIZE - 1);
	char *kaddr;
	struct page *p;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
	unsigned long end_i = (start_offset + start + min_len - 1) >>
		PAGE_CACHE_SHIFT;

	if (i != end_i)
		return -EINVAL;

	if (i == 0) {
		offset = start_offset;
		*map_start = 0;
	} else {
		offset = 0;
		*map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
	}
C
Chris Mason 已提交
3723

3724
	if (start + min_len > eb->len) {
C
Chris Mason 已提交
3725 3726 3727
		printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
		       "wanted %lu %lu\n", (unsigned long long)eb->start,
		       eb->len, start, min_len);
3728
		WARN_ON(1);
3729
		return -EINVAL;
3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786
	}

	p = extent_buffer_page(eb, i);
	kaddr = kmap_atomic(p, km);
	*token = kaddr;
	*map = kaddr + offset;
	*map_len = PAGE_CACHE_SIZE - offset;
	return 0;
}

int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
		      unsigned long min_len,
		      char **token, char **map,
		      unsigned long *map_start,
		      unsigned long *map_len, int km)
{
	int err;
	int save = 0;
	if (eb->map_token) {
		unmap_extent_buffer(eb, eb->map_token, km);
		eb->map_token = NULL;
		save = 1;
	}
	err = map_private_extent_buffer(eb, start, min_len, token, map,
				       map_start, map_len, km);
	if (!err && save) {
		eb->map_token = *token;
		eb->kaddr = *map;
		eb->map_start = *map_start;
		eb->map_len = *map_len;
	}
	return err;
}

void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
{
	kunmap_atomic(token, km);
}

int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
			  unsigned long start,
			  unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	char *ptr = (char *)ptrv;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
	int ret = 0;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);

C
Chris Mason 已提交
3787
	while (len > 0) {
3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821
		page = extent_buffer_page(eb, i);

		cur = min(len, (PAGE_CACHE_SIZE - offset));

		kaddr = kmap_atomic(page, KM_USER0);
		ret = memcmp(ptr, kaddr + offset, cur);
		kunmap_atomic(kaddr, KM_USER0);
		if (ret)
			break;

		ptr += cur;
		len -= cur;
		offset = 0;
		i++;
	}
	return ret;
}

void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
			 unsigned long start, unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	char *src = (char *)srcv;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);

C
Chris Mason 已提交
3822
	while (len > 0) {
3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
		kaddr = kmap_atomic(page, KM_USER1);
		memcpy(kaddr + offset, src, cur);
		kunmap_atomic(kaddr, KM_USER1);

		src += cur;
		len -= cur;
		offset = 0;
		i++;
	}
}

void memset_extent_buffer(struct extent_buffer *eb, char c,
			  unsigned long start, unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

	offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);

C
Chris Mason 已提交
3853
	while (len > 0) {
3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
		kaddr = kmap_atomic(page, KM_USER0);
		memset(kaddr + offset, c, cur);
		kunmap_atomic(kaddr, KM_USER0);

		len -= cur;
		offset = 0;
		i++;
	}
}

void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
			unsigned long dst_offset, unsigned long src_offset,
			unsigned long len)
{
	u64 dst_len = dst->len;
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;

	WARN_ON(src->len != dst_len);

	offset = (start_offset + dst_offset) &
		((unsigned long)PAGE_CACHE_SIZE - 1);

C
Chris Mason 已提交
3885
	while (len > 0) {
3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921
		page = extent_buffer_page(dst, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));

		kaddr = kmap_atomic(page, KM_USER0);
		read_extent_buffer(src, kaddr + offset, src_offset, cur);
		kunmap_atomic(kaddr, KM_USER0);

		src_offset += cur;
		len -= cur;
		offset = 0;
		i++;
	}
}

static void move_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
	char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
	if (dst_page == src_page) {
		memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
	} else {
		char *src_kaddr = kmap_atomic(src_page, KM_USER1);
		char *p = dst_kaddr + dst_off + len;
		char *s = src_kaddr + src_off + len;

		while (len--)
			*--p = *--s;

		kunmap_atomic(src_kaddr, KM_USER1);
	}
	kunmap_atomic(dst_kaddr, KM_USER0);
}

3922 3923 3924 3925 3926 3927
static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
{
	unsigned long distance = (src > dst) ? src - dst : dst - src;
	return distance < len;
}

3928 3929 3930 3931 3932 3933 3934
static void copy_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
	char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
	char *src_kaddr;

3935
	if (dst_page != src_page) {
3936
		src_kaddr = kmap_atomic(src_page, KM_USER1);
3937
	} else {
3938
		src_kaddr = dst_kaddr;
3939 3940
		BUG_ON(areas_overlap(src_off, dst_off, len));
	}
3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958

	memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
	kunmap_atomic(dst_kaddr, KM_USER0);
	if (dst_page != src_page)
		kunmap_atomic(src_kaddr, KM_USER1);
}

void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
			   unsigned long src_offset, unsigned long len)
{
	size_t cur;
	size_t dst_off_in_page;
	size_t src_off_in_page;
	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long dst_i;
	unsigned long src_i;

	if (src_offset + len > dst->len) {
C
Chris Mason 已提交
3959 3960
		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
3961 3962 3963
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
C
Chris Mason 已提交
3964 3965
		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
3966 3967 3968
		BUG_ON(1);
	}

C
Chris Mason 已提交
3969
	while (len > 0) {
3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005
		dst_off_in_page = (start_offset + dst_offset) &
			((unsigned long)PAGE_CACHE_SIZE - 1);
		src_off_in_page = (start_offset + src_offset) &
			((unsigned long)PAGE_CACHE_SIZE - 1);

		dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
		src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;

		cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
					       src_off_in_page));
		cur = min_t(unsigned long, cur,
			(unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));

		copy_pages(extent_buffer_page(dst, dst_i),
			   extent_buffer_page(dst, src_i),
			   dst_off_in_page, src_off_in_page, cur);

		src_offset += cur;
		dst_offset += cur;
		len -= cur;
	}
}

void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
			   unsigned long src_offset, unsigned long len)
{
	size_t cur;
	size_t dst_off_in_page;
	size_t src_off_in_page;
	unsigned long dst_end = dst_offset + len - 1;
	unsigned long src_end = src_offset + len - 1;
	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long dst_i;
	unsigned long src_i;

	if (src_offset + len > dst->len) {
C
Chris Mason 已提交
4006 4007
		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
		       "len %lu len %lu\n", src_offset, len, dst->len);
4008 4009 4010
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
C
Chris Mason 已提交
4011 4012
		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
		       "len %lu len %lu\n", dst_offset, len, dst->len);
4013 4014
		BUG_ON(1);
	}
4015
	if (!areas_overlap(src_offset, dst_offset, len)) {
4016 4017 4018
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
4019
	while (len > 0) {
4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039
		dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
		src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;

		dst_off_in_page = (start_offset + dst_end) &
			((unsigned long)PAGE_CACHE_SIZE - 1);
		src_off_in_page = (start_offset + src_end) &
			((unsigned long)PAGE_CACHE_SIZE - 1);

		cur = min_t(unsigned long, len, src_off_in_page + 1);
		cur = min(cur, dst_off_in_page + 1);
		move_pages(extent_buffer_page(dst, dst_i),
			   extent_buffer_page(dst, src_i),
			   dst_off_in_page - cur + 1,
			   src_off_in_page - cur + 1, cur);

		dst_end -= cur;
		src_end -= cur;
		len -= cur;
	}
}
4040

4041 4042 4043 4044 4045 4046 4047 4048
static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
{
	struct extent_buffer *eb =
			container_of(head, struct extent_buffer, rcu_head);

	btrfs_release_extent_buffer(eb);
}

4049 4050 4051 4052 4053 4054 4055
int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
{
	u64 start = page_offset(page);
	struct extent_buffer *eb;
	int ret = 1;

	spin_lock(&tree->buffer_lock);
4056
	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
4057 4058 4059 4060
	if (!eb) {
		spin_unlock(&tree->buffer_lock);
		return ret;
	}
4061

4062
	if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
4063 4064 4065
		ret = 0;
		goto out;
	}
4066 4067 4068 4069 4070 4071

	/*
	 * set @eb->refs to 0 if it is already 1, and then release the @eb.
	 * Or go back.
	 */
	if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
4072 4073 4074
		ret = 0;
		goto out;
	}
4075

4076
	radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
4077 4078
out:
	spin_unlock(&tree->buffer_lock);
4079 4080 4081 4082

	/* at this point we can safely release the extent buffer */
	if (atomic_read(&eb->refs) == 0)
		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
4083 4084
	return ret;
}