1#include <linux/bitops.h>
   2#include <linux/slab.h>
   3#include <linux/bio.h>
   4#include <linux/mm.h>
   5#include <linux/pagemap.h>
   6#include <linux/page-flags.h>
 
   7#include <linux/spinlock.h>
   8#include <linux/blkdev.h>
   9#include <linux/swap.h>
  10#include <linux/writeback.h>
  11#include <linux/pagevec.h>
  12#include <linux/prefetch.h>
  13#include <linux/cleancache.h>
  14#include "extent_io.h"
 
  15#include "extent_map.h"
  16#include "ctree.h"
  17#include "btrfs_inode.h"
  18#include "volumes.h"
  19#include "check-integrity.h"
  20#include "locking.h"
  21#include "rcu-string.h"
  22#include "backref.h"
 
 
 
 
 
 
 
 
 
 
 
  23#include "transaction.h"
  24
  25static struct kmem_cache *extent_state_cache;
  26static struct kmem_cache *extent_buffer_cache;
  27static struct bio_set *btrfs_bioset;
  28
  29static inline bool extent_state_in_tree(const struct extent_state *state)
  30{
  31	return !RB_EMPTY_NODE(&state->rb_node);
  32}
  33
  34#ifdef CONFIG_BTRFS_DEBUG
  35static LIST_HEAD(buffers);
  36static LIST_HEAD(states);
  37
  38static DEFINE_SPINLOCK(leak_lock);
  39
  40static inline
  41void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
  42{
 
  43	unsigned long flags;
  44
  45	spin_lock_irqsave(&leak_lock, flags);
  46	list_add(new, head);
  47	spin_unlock_irqrestore(&leak_lock, flags);
  48}
  49
  50static inline
  51void btrfs_leak_debug_del(struct list_head *entry)
  52{
 
  53	unsigned long flags;
  54
  55	spin_lock_irqsave(&leak_lock, flags);
  56	list_del(entry);
  57	spin_unlock_irqrestore(&leak_lock, flags);
  58}
  59
  60static inline
  61void btrfs_leak_debug_check(void)
  62{
  63	struct extent_state *state;
  64	struct extent_buffer *eb;
 
  65
  66	while (!list_empty(&states)) {
  67		state = list_entry(states.next, struct extent_state, leak_list);
  68		pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
  69		       state->start, state->end, state->state,
  70		       extent_state_in_tree(state),
  71		       atomic_read(&state->refs));
  72		list_del(&state->leak_list);
  73		kmem_cache_free(extent_state_cache, state);
  74	}
  75
  76	while (!list_empty(&buffers)) {
  77		eb = list_entry(buffers.next, struct extent_buffer, leak_list);
  78		pr_err("BTRFS: buffer leak start %llu len %lu refs %d\n",
  79		       eb->start, eb->len, atomic_read(&eb->refs));
 
 
 
 
 
  80		list_del(&eb->leak_list);
 
  81		kmem_cache_free(extent_buffer_cache, eb);
  82	}
  83}
  84
  85#define btrfs_debug_check_extent_io_range(tree, start, end)		\
  86	__btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
  87static inline void __btrfs_debug_check_extent_io_range(const char *caller,
  88		struct extent_io_tree *tree, u64 start, u64 end)
  89{
  90	struct inode *inode;
  91	u64 isize;
  92
  93	if (!tree->mapping)
  94		return;
  95
  96	inode = tree->mapping->host;
  97	isize = i_size_read(inode);
  98	if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
  99		btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
 100		    "%s: ino %llu isize %llu odd range [%llu,%llu]",
 101				caller, btrfs_ino(inode), isize, start, end);
 102	}
 103}
 104#else
 105#define btrfs_leak_debug_add(new, head)	do {} while (0)
 106#define btrfs_leak_debug_del(entry)	do {} while (0)
 107#define btrfs_leak_debug_check()	do {} while (0)
 108#define btrfs_debug_check_extent_io_range(c, s, e)	do {} while (0)
 109#endif
 110
 111#define BUFFER_LRU_MAX 64
 112
 113struct tree_entry {
 114	u64 start;
 115	u64 end;
 116	struct rb_node rb_node;
 117};
 118
 119struct extent_page_data {
 120	struct bio *bio;
 121	struct extent_io_tree *tree;
 122	get_extent_t *get_extent;
 123	unsigned long bio_flags;
 124
 125	/* tells writepage not to lock the state bits for this range
 126	 * it still does the unlocking
 127	 */
 128	unsigned int extent_locked:1;
 129
 130	/* tells the submit_bio code to use REQ_SYNC */
 131	unsigned int sync_io:1;
 132};
 133
 134static void add_extent_changeset(struct extent_state *state, unsigned bits,
 135				 struct extent_changeset *changeset,
 136				 int set)
 137{
 138	int ret;
 139
 140	if (!changeset)
 141		return;
 142	if (set && (state->state & bits) == bits)
 143		return;
 144	if (!set && (state->state & bits) == 0)
 145		return;
 146	changeset->bytes_changed += state->end - state->start + 1;
 147	ret = ulist_add(changeset->range_changed, state->start, state->end,
 148			GFP_ATOMIC);
 149	/* ENOMEM */
 150	BUG_ON(ret < 0);
 151}
 152
 153static noinline void flush_write_bio(void *data);
 154static inline struct btrfs_fs_info *
 155tree_fs_info(struct extent_io_tree *tree)
 156{
 157	if (!tree->mapping)
 158		return NULL;
 159	return btrfs_sb(tree->mapping->host->i_sb);
 160}
 161
 162int __init extent_io_init(void)
 163{
 164	extent_state_cache = kmem_cache_create("btrfs_extent_state",
 165			sizeof(struct extent_state), 0,
 166			SLAB_MEM_SPREAD, NULL);
 167	if (!extent_state_cache)
 168		return -ENOMEM;
 169
 170	extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
 171			sizeof(struct extent_buffer), 0,
 172			SLAB_MEM_SPREAD, NULL);
 173	if (!extent_buffer_cache)
 174		goto free_state_cache;
 175
 176	btrfs_bioset = bioset_create(BIO_POOL_SIZE,
 177				     offsetof(struct btrfs_io_bio, bio));
 178	if (!btrfs_bioset)
 179		goto free_buffer_cache;
 180
 181	if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
 182		goto free_bioset;
 183
 184	return 0;
 185
 186free_bioset:
 187	bioset_free(btrfs_bioset);
 188	btrfs_bioset = NULL;
 189
 190free_buffer_cache:
 191	kmem_cache_destroy(extent_buffer_cache);
 192	extent_buffer_cache = NULL;
 193
 194free_state_cache:
 195	kmem_cache_destroy(extent_state_cache);
 196	extent_state_cache = NULL;
 197	return -ENOMEM;
 198}
 199
 200void extent_io_exit(void)
 201{
 202	btrfs_leak_debug_check();
 203
 204	/*
 205	 * Make sure all delayed rcu free are flushed before we
 206	 * destroy caches.
 
 207	 */
 208	rcu_barrier();
 209	kmem_cache_destroy(extent_state_cache);
 210	kmem_cache_destroy(extent_buffer_cache);
 211	if (btrfs_bioset)
 212		bioset_free(btrfs_bioset);
 213}
 214
 215void extent_io_tree_init(struct extent_io_tree *tree,
 216			 struct address_space *mapping)
 217{
 218	tree->state = RB_ROOT;
 219	tree->ops = NULL;
 220	tree->dirty_bytes = 0;
 221	spin_lock_init(&tree->lock);
 222	tree->mapping = mapping;
 223}
 224
 225static struct extent_state *alloc_extent_state(gfp_t mask)
 226{
 227	struct extent_state *state;
 228
 229	state = kmem_cache_alloc(extent_state_cache, mask);
 230	if (!state)
 231		return state;
 232	state->state = 0;
 233	state->failrec = NULL;
 234	RB_CLEAR_NODE(&state->rb_node);
 235	btrfs_leak_debug_add(&state->leak_list, &states);
 236	atomic_set(&state->refs, 1);
 237	init_waitqueue_head(&state->wq);
 238	trace_alloc_extent_state(state, mask, _RET_IP_);
 239	return state;
 240}
 241
 242void free_extent_state(struct extent_state *state)
 243{
 244	if (!state)
 245		return;
 246	if (atomic_dec_and_test(&state->refs)) {
 247		WARN_ON(extent_state_in_tree(state));
 248		btrfs_leak_debug_del(&state->leak_list);
 249		trace_free_extent_state(state, _RET_IP_);
 250		kmem_cache_free(extent_state_cache, state);
 251	}
 252}
 253
 254static struct rb_node *tree_insert(struct rb_root *root,
 255				   struct rb_node *search_start,
 256				   u64 offset,
 257				   struct rb_node *node,
 258				   struct rb_node ***p_in,
 259				   struct rb_node **parent_in)
 260{
 261	struct rb_node **p;
 262	struct rb_node *parent = NULL;
 263	struct tree_entry *entry;
 264
 265	if (p_in && parent_in) {
 266		p = *p_in;
 267		parent = *parent_in;
 268		goto do_insert;
 269	}
 270
 271	p = search_start ? &search_start : &root->rb_node;
 272	while (*p) {
 273		parent = *p;
 274		entry = rb_entry(parent, struct tree_entry, rb_node);
 275
 276		if (offset < entry->start)
 277			p = &(*p)->rb_left;
 278		else if (offset > entry->end)
 279			p = &(*p)->rb_right;
 280		else
 281			return parent;
 282	}
 283
 284do_insert:
 285	rb_link_node(node, parent, p);
 286	rb_insert_color(node, root);
 287	return NULL;
 288}
 289
 290static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
 291				      struct rb_node **prev_ret,
 292				      struct rb_node **next_ret,
 293				      struct rb_node ***p_ret,
 294				      struct rb_node **parent_ret)
 295{
 296	struct rb_root *root = &tree->state;
 297	struct rb_node **n = &root->rb_node;
 298	struct rb_node *prev = NULL;
 299	struct rb_node *orig_prev = NULL;
 300	struct tree_entry *entry;
 301	struct tree_entry *prev_entry = NULL;
 302
 303	while (*n) {
 304		prev = *n;
 305		entry = rb_entry(prev, struct tree_entry, rb_node);
 306		prev_entry = entry;
 307
 308		if (offset < entry->start)
 309			n = &(*n)->rb_left;
 310		else if (offset > entry->end)
 311			n = &(*n)->rb_right;
 312		else
 313			return *n;
 314	}
 315
 316	if (p_ret)
 317		*p_ret = n;
 318	if (parent_ret)
 319		*parent_ret = prev;
 320
 321	if (prev_ret) {
 322		orig_prev = prev;
 323		while (prev && offset > prev_entry->end) {
 324			prev = rb_next(prev);
 325			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 326		}
 327		*prev_ret = prev;
 328		prev = orig_prev;
 329	}
 330
 331	if (next_ret) {
 332		prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 333		while (prev && offset < prev_entry->start) {
 334			prev = rb_prev(prev);
 335			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 336		}
 337		*next_ret = prev;
 338	}
 339	return NULL;
 340}
 341
 342static inline struct rb_node *
 343tree_search_for_insert(struct extent_io_tree *tree,
 344		       u64 offset,
 345		       struct rb_node ***p_ret,
 346		       struct rb_node **parent_ret)
 347{
 348	struct rb_node *prev = NULL;
 349	struct rb_node *ret;
 350
 351	ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
 352	if (!ret)
 353		return prev;
 354	return ret;
 355}
 356
 357static inline struct rb_node *tree_search(struct extent_io_tree *tree,
 358					  u64 offset)
 359{
 360	return tree_search_for_insert(tree, offset, NULL, NULL);
 361}
 362
 363static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
 364		     struct extent_state *other)
 365{
 366	if (tree->ops && tree->ops->merge_extent_hook)
 367		tree->ops->merge_extent_hook(tree->mapping->host, new,
 368					     other);
 369}
 370
 371/*
 372 * utility function to look for merge candidates inside a given range.
 373 * Any extents with matching state are merged together into a single
 374 * extent in the tree.  Extents with EXTENT_IO in their state field
 375 * are not merged because the end_io handlers need to be able to do
 376 * operations on them without sleeping (or doing allocations/splits).
 377 *
 378 * This should be called with the tree lock held.
 379 */
 380static void merge_state(struct extent_io_tree *tree,
 381		        struct extent_state *state)
 382{
 383	struct extent_state *other;
 384	struct rb_node *other_node;
 385
 386	if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
 387		return;
 388
 389	other_node = rb_prev(&state->rb_node);
 390	if (other_node) {
 391		other = rb_entry(other_node, struct extent_state, rb_node);
 392		if (other->end == state->start - 1 &&
 393		    other->state == state->state) {
 394			merge_cb(tree, state, other);
 395			state->start = other->start;
 396			rb_erase(&other->rb_node, &tree->state);
 397			RB_CLEAR_NODE(&other->rb_node);
 398			free_extent_state(other);
 399		}
 400	}
 401	other_node = rb_next(&state->rb_node);
 402	if (other_node) {
 403		other = rb_entry(other_node, struct extent_state, rb_node);
 404		if (other->start == state->end + 1 &&
 405		    other->state == state->state) {
 406			merge_cb(tree, state, other);
 407			state->end = other->end;
 408			rb_erase(&other->rb_node, &tree->state);
 409			RB_CLEAR_NODE(&other->rb_node);
 410			free_extent_state(other);
 411		}
 412	}
 413}
 414
 415static void set_state_cb(struct extent_io_tree *tree,
 416			 struct extent_state *state, unsigned *bits)
 417{
 418	if (tree->ops && tree->ops->set_bit_hook)
 419		tree->ops->set_bit_hook(tree->mapping->host, state, bits);
 420}
 421
 422static void clear_state_cb(struct extent_io_tree *tree,
 423			   struct extent_state *state, unsigned *bits)
 424{
 425	if (tree->ops && tree->ops->clear_bit_hook)
 426		tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
 427}
 428
 429static void set_state_bits(struct extent_io_tree *tree,
 430			   struct extent_state *state, unsigned *bits,
 431			   struct extent_changeset *changeset);
 432
 433/*
 434 * insert an extent_state struct into the tree.  'bits' are set on the
 435 * struct before it is inserted.
 436 *
 437 * This may return -EEXIST if the extent is already there, in which case the
 438 * state struct is freed.
 439 *
 440 * The tree lock is not taken internally.  This is a utility function and
 441 * probably isn't what you want to call (see set/clear_extent_bit).
 442 */
 443static int insert_state(struct extent_io_tree *tree,
 444			struct extent_state *state, u64 start, u64 end,
 445			struct rb_node ***p,
 446			struct rb_node **parent,
 447			unsigned *bits, struct extent_changeset *changeset)
 448{
 449	struct rb_node *node;
 450
 451	if (end < start)
 452		WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
 453		       end, start);
 454	state->start = start;
 455	state->end = end;
 456
 457	set_state_bits(tree, state, bits, changeset);
 458
 459	node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
 460	if (node) {
 461		struct extent_state *found;
 462		found = rb_entry(node, struct extent_state, rb_node);
 463		pr_err("BTRFS: found node %llu %llu on insert of %llu %llu\n",
 464		       found->start, found->end, start, end);
 465		return -EEXIST;
 466	}
 467	merge_state(tree, state);
 468	return 0;
 469}
 470
 471static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
 472		     u64 split)
 473{
 474	if (tree->ops && tree->ops->split_extent_hook)
 475		tree->ops->split_extent_hook(tree->mapping->host, orig, split);
 476}
 477
 478/*
 479 * split a given extent state struct in two, inserting the preallocated
 480 * struct 'prealloc' as the newly created second half.  'split' indicates an
 481 * offset inside 'orig' where it should be split.
 482 *
 483 * Before calling,
 484 * the tree has 'orig' at [orig->start, orig->end].  After calling, there
 485 * are two extent state structs in the tree:
 486 * prealloc: [orig->start, split - 1]
 487 * orig: [ split, orig->end ]
 488 *
 489 * The tree locks are not taken by this function. They need to be held
 490 * by the caller.
 491 */
 492static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 493		       struct extent_state *prealloc, u64 split)
 494{
 495	struct rb_node *node;
 496
 497	split_cb(tree, orig, split);
 498
 499	prealloc->start = orig->start;
 500	prealloc->end = split - 1;
 501	prealloc->state = orig->state;
 502	orig->start = split;
 503
 504	node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
 505			   &prealloc->rb_node, NULL, NULL);
 506	if (node) {
 507		free_extent_state(prealloc);
 508		return -EEXIST;
 509	}
 510	return 0;
 511}
 512
 513static struct extent_state *next_state(struct extent_state *state)
 514{
 515	struct rb_node *next = rb_next(&state->rb_node);
 516	if (next)
 517		return rb_entry(next, struct extent_state, rb_node);
 518	else
 519		return NULL;
 520}
 521
 522/*
 523 * utility function to clear some bits in an extent state struct.
 524 * it will optionally wake up any one waiting on this state (wake == 1).
 525 *
 526 * If no bits are set on the state struct after clearing things, the
 527 * struct is freed and removed from the tree
 528 */
 529static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
 530					    struct extent_state *state,
 531					    unsigned *bits, int wake,
 532					    struct extent_changeset *changeset)
 533{
 534	struct extent_state *next;
 535	unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
 536
 537	if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
 538		u64 range = state->end - state->start + 1;
 539		WARN_ON(range > tree->dirty_bytes);
 540		tree->dirty_bytes -= range;
 541	}
 542	clear_state_cb(tree, state, bits);
 543	add_extent_changeset(state, bits_to_clear, changeset, 0);
 544	state->state &= ~bits_to_clear;
 545	if (wake)
 546		wake_up(&state->wq);
 547	if (state->state == 0) {
 548		next = next_state(state);
 549		if (extent_state_in_tree(state)) {
 550			rb_erase(&state->rb_node, &tree->state);
 551			RB_CLEAR_NODE(&state->rb_node);
 552			free_extent_state(state);
 553		} else {
 554			WARN_ON(1);
 555		}
 556	} else {
 557		merge_state(tree, state);
 558		next = next_state(state);
 559	}
 560	return next;
 561}
 562
 563static struct extent_state *
 564alloc_extent_state_atomic(struct extent_state *prealloc)
 565{
 566	if (!prealloc)
 567		prealloc = alloc_extent_state(GFP_ATOMIC);
 
 
 
 568
 569	return prealloc;
 570}
 571
 572static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
 573{
 574	btrfs_panic(tree_fs_info(tree), err,
 575		    "Locking error: Extent tree was modified by another thread while locked.");
 576}
 577
 578/*
 579 * clear some bits on a range in the tree.  This may require splitting
 580 * or inserting elements in the tree, so the gfp mask is used to
 581 * indicate which allocations or sleeping are allowed.
 582 *
 583 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
 584 * the given range from the tree regardless of state (ie for truncate).
 585 *
 586 * the range [start, end] is inclusive.
 587 *
 588 * This takes the tree lock, and returns 0 on success and < 0 on error.
 589 */
 590static int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 591			      unsigned bits, int wake, int delete,
 592			      struct extent_state **cached_state,
 593			      gfp_t mask, struct extent_changeset *changeset)
 594{
 595	struct extent_state *state;
 596	struct extent_state *cached;
 597	struct extent_state *prealloc = NULL;
 598	struct rb_node *node;
 599	u64 last_end;
 600	int err;
 601	int clear = 0;
 602
 603	btrfs_debug_check_extent_io_range(tree, start, end);
 604
 605	if (bits & EXTENT_DELALLOC)
 606		bits |= EXTENT_NORESERVE;
 607
 608	if (delete)
 609		bits |= ~EXTENT_CTLBITS;
 610	bits |= EXTENT_FIRST_DELALLOC;
 611
 612	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
 613		clear = 1;
 614again:
 615	if (!prealloc && gfpflags_allow_blocking(mask)) {
 616		/*
 617		 * Don't care for allocation failure here because we might end
 618		 * up not needing the pre-allocated extent state at all, which
 619		 * is the case if we only have in the tree extent states that
 620		 * cover our input range and don't cover too any other range.
 621		 * If we end up needing a new extent state we allocate it later.
 622		 */
 623		prealloc = alloc_extent_state(mask);
 624	}
 625
 626	spin_lock(&tree->lock);
 627	if (cached_state) {
 628		cached = *cached_state;
 629
 630		if (clear) {
 631			*cached_state = NULL;
 632			cached_state = NULL;
 633		}
 634
 635		if (cached && extent_state_in_tree(cached) &&
 636		    cached->start <= start && cached->end > start) {
 637			if (clear)
 638				atomic_dec(&cached->refs);
 639			state = cached;
 640			goto hit_next;
 641		}
 642		if (clear)
 643			free_extent_state(cached);
 644	}
 645	/*
 646	 * this search will find the extents that end after
 647	 * our range starts
 648	 */
 649	node = tree_search(tree, start);
 650	if (!node)
 651		goto out;
 652	state = rb_entry(node, struct extent_state, rb_node);
 653hit_next:
 654	if (state->start > end)
 655		goto out;
 656	WARN_ON(state->end < start);
 657	last_end = state->end;
 658
 659	/* the state doesn't have the wanted bits, go ahead */
 660	if (!(state->state & bits)) {
 661		state = next_state(state);
 662		goto next;
 663	}
 664
 665	/*
 666	 *     | ---- desired range ---- |
 667	 *  | state | or
 668	 *  | ------------- state -------------- |
 669	 *
 670	 * We need to split the extent we found, and may flip
 671	 * bits on second half.
 672	 *
 673	 * If the extent we found extends past our range, we
 674	 * just split and search again.  It'll get split again
 675	 * the next time though.
 676	 *
 677	 * If the extent we found is inside our range, we clear
 678	 * the desired bit on it.
 679	 */
 680
 681	if (state->start < start) {
 682		prealloc = alloc_extent_state_atomic(prealloc);
 683		BUG_ON(!prealloc);
 684		err = split_state(tree, state, prealloc, start);
 685		if (err)
 686			extent_io_tree_panic(tree, err);
 687
 688		prealloc = NULL;
 689		if (err)
 690			goto out;
 691		if (state->end <= end) {
 692			state = clear_state_bit(tree, state, &bits, wake,
 693						changeset);
 694			goto next;
 695		}
 696		goto search_again;
 697	}
 698	/*
 699	 * | ---- desired range ---- |
 700	 *                        | state |
 701	 * We need to split the extent, and clear the bit
 702	 * on the first half
 703	 */
 704	if (state->start <= end && state->end > end) {
 705		prealloc = alloc_extent_state_atomic(prealloc);
 706		BUG_ON(!prealloc);
 707		err = split_state(tree, state, prealloc, end + 1);
 708		if (err)
 709			extent_io_tree_panic(tree, err);
 710
 711		if (wake)
 712			wake_up(&state->wq);
 713
 714		clear_state_bit(tree, prealloc, &bits, wake, changeset);
 715
 716		prealloc = NULL;
 717		goto out;
 718	}
 719
 720	state = clear_state_bit(tree, state, &bits, wake, changeset);
 721next:
 722	if (last_end == (u64)-1)
 723		goto out;
 724	start = last_end + 1;
 725	if (start <= end && state && !need_resched())
 726		goto hit_next;
 727
 728search_again:
 729	if (start > end)
 730		goto out;
 731	spin_unlock(&tree->lock);
 732	if (gfpflags_allow_blocking(mask))
 733		cond_resched();
 734	goto again;
 735
 736out:
 737	spin_unlock(&tree->lock);
 738	if (prealloc)
 739		free_extent_state(prealloc);
 740
 741	return 0;
 742
 743}
 744
 745static void wait_on_state(struct extent_io_tree *tree,
 746			  struct extent_state *state)
 747		__releases(tree->lock)
 748		__acquires(tree->lock)
 749{
 750	DEFINE_WAIT(wait);
 751	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
 752	spin_unlock(&tree->lock);
 753	schedule();
 754	spin_lock(&tree->lock);
 755	finish_wait(&state->wq, &wait);
 756}
 757
 758/*
 759 * waits for one or more bits to clear on a range in the state tree.
 760 * The range [start, end] is inclusive.
 761 * The tree lock is taken by this function
 762 */
 763static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 764			    unsigned long bits)
 765{
 766	struct extent_state *state;
 767	struct rb_node *node;
 768
 769	btrfs_debug_check_extent_io_range(tree, start, end);
 770
 771	spin_lock(&tree->lock);
 772again:
 773	while (1) {
 774		/*
 775		 * this search will find all the extents that end after
 776		 * our range starts
 777		 */
 778		node = tree_search(tree, start);
 779process_node:
 780		if (!node)
 781			break;
 782
 783		state = rb_entry(node, struct extent_state, rb_node);
 784
 785		if (state->start > end)
 786			goto out;
 787
 788		if (state->state & bits) {
 789			start = state->start;
 790			atomic_inc(&state->refs);
 791			wait_on_state(tree, state);
 792			free_extent_state(state);
 793			goto again;
 794		}
 795		start = state->end + 1;
 796
 797		if (start > end)
 798			break;
 799
 800		if (!cond_resched_lock(&tree->lock)) {
 801			node = rb_next(node);
 802			goto process_node;
 803		}
 804	}
 805out:
 806	spin_unlock(&tree->lock);
 807}
 808
 809static void set_state_bits(struct extent_io_tree *tree,
 810			   struct extent_state *state,
 811			   unsigned *bits, struct extent_changeset *changeset)
 812{
 813	unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
 814
 815	set_state_cb(tree, state, bits);
 816	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
 817		u64 range = state->end - state->start + 1;
 818		tree->dirty_bytes += range;
 
 819	}
 820	add_extent_changeset(state, bits_to_set, changeset, 1);
 821	state->state |= bits_to_set;
 822}
 823
 824static void cache_state_if_flags(struct extent_state *state,
 825				 struct extent_state **cached_ptr,
 826				 unsigned flags)
 827{
 828	if (cached_ptr && !(*cached_ptr)) {
 829		if (!flags || (state->state & flags)) {
 830			*cached_ptr = state;
 831			atomic_inc(&state->refs);
 832		}
 833	}
 834}
 835
 836static void cache_state(struct extent_state *state,
 837			struct extent_state **cached_ptr)
 
 838{
 839	return cache_state_if_flags(state, cached_ptr,
 840				    EXTENT_IOBITS | EXTENT_BOUNDARY);
 841}
 842
 843/*
 844 * set some bits on a range in the tree.  This may require allocations or
 845 * sleeping, so the gfp mask is used to indicate what is allowed.
 846 *
 847 * If any of the exclusive bits are set, this will fail with -EEXIST if some
 848 * part of the range already has the desired bits set.  The start of the
 849 * existing range is returned in failed_start in this case.
 850 *
 851 * [start, end] is inclusive This takes the tree lock.
 852 */
 853
 854static int __must_check
 855__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 856		 unsigned bits, unsigned exclusive_bits,
 857		 u64 *failed_start, struct extent_state **cached_state,
 858		 gfp_t mask, struct extent_changeset *changeset)
 859{
 860	struct extent_state *state;
 861	struct extent_state *prealloc = NULL;
 862	struct rb_node *node;
 863	struct rb_node **p;
 864	struct rb_node *parent;
 865	int err = 0;
 866	u64 last_start;
 867	u64 last_end;
 868
 869	btrfs_debug_check_extent_io_range(tree, start, end);
 870
 871	bits |= EXTENT_FIRST_DELALLOC;
 872again:
 873	if (!prealloc && gfpflags_allow_blocking(mask)) {
 874		/*
 875		 * Don't care for allocation failure here because we might end
 876		 * up not needing the pre-allocated extent state at all, which
 877		 * is the case if we only have in the tree extent states that
 878		 * cover our input range and don't cover too any other range.
 879		 * If we end up needing a new extent state we allocate it later.
 880		 */
 881		prealloc = alloc_extent_state(mask);
 882	}
 883
 884	spin_lock(&tree->lock);
 885	if (cached_state && *cached_state) {
 886		state = *cached_state;
 887		if (state->start <= start && state->end > start &&
 888		    extent_state_in_tree(state)) {
 889			node = &state->rb_node;
 890			goto hit_next;
 891		}
 892	}
 893	/*
 894	 * this search will find all the extents that end after
 895	 * our range starts.
 896	 */
 897	node = tree_search_for_insert(tree, start, &p, &parent);
 898	if (!node) {
 899		prealloc = alloc_extent_state_atomic(prealloc);
 900		BUG_ON(!prealloc);
 901		err = insert_state(tree, prealloc, start, end,
 902				   &p, &parent, &bits, changeset);
 903		if (err)
 904			extent_io_tree_panic(tree, err);
 905
 906		cache_state(prealloc, cached_state);
 907		prealloc = NULL;
 908		goto out;
 909	}
 910	state = rb_entry(node, struct extent_state, rb_node);
 911hit_next:
 912	last_start = state->start;
 913	last_end = state->end;
 914
 915	/*
 916	 * | ---- desired range ---- |
 917	 * | state |
 918	 *
 919	 * Just lock what we found and keep going
 920	 */
 921	if (state->start == start && state->end <= end) {
 922		if (state->state & exclusive_bits) {
 923			*failed_start = state->start;
 924			err = -EEXIST;
 925			goto out;
 926		}
 927
 928		set_state_bits(tree, state, &bits, changeset);
 929		cache_state(state, cached_state);
 930		merge_state(tree, state);
 931		if (last_end == (u64)-1)
 932			goto out;
 933		start = last_end + 1;
 934		state = next_state(state);
 935		if (start < end && state && state->start == start &&
 936		    !need_resched())
 937			goto hit_next;
 938		goto search_again;
 939	}
 940
 941	/*
 942	 *     | ---- desired range ---- |
 943	 * | state |
 944	 *   or
 945	 * | ------------- state -------------- |
 946	 *
 947	 * We need to split the extent we found, and may flip bits on
 948	 * second half.
 949	 *
 950	 * If the extent we found extends past our
 951	 * range, we just split and search again.  It'll get split
 952	 * again the next time though.
 953	 *
 954	 * If the extent we found is inside our range, we set the
 955	 * desired bit on it.
 956	 */
 957	if (state->start < start) {
 958		if (state->state & exclusive_bits) {
 959			*failed_start = start;
 960			err = -EEXIST;
 961			goto out;
 962		}
 963
 964		prealloc = alloc_extent_state_atomic(prealloc);
 965		BUG_ON(!prealloc);
 966		err = split_state(tree, state, prealloc, start);
 967		if (err)
 968			extent_io_tree_panic(tree, err);
 969
 970		prealloc = NULL;
 971		if (err)
 972			goto out;
 973		if (state->end <= end) {
 974			set_state_bits(tree, state, &bits, changeset);
 975			cache_state(state, cached_state);
 976			merge_state(tree, state);
 977			if (last_end == (u64)-1)
 978				goto out;
 979			start = last_end + 1;
 980			state = next_state(state);
 981			if (start < end && state && state->start == start &&
 982			    !need_resched())
 983				goto hit_next;
 984		}
 985		goto search_again;
 986	}
 987	/*
 988	 * | ---- desired range ---- |
 989	 *     | state | or               | state |
 990	 *
 991	 * There's a hole, we need to insert something in it and
 992	 * ignore the extent we found.
 993	 */
 994	if (state->start > start) {
 995		u64 this_end;
 996		if (end < last_start)
 997			this_end = end;
 998		else
 999			this_end = last_start - 1;
1000
1001		prealloc = alloc_extent_state_atomic(prealloc);
1002		BUG_ON(!prealloc);
 
 
1003
1004		/*
1005		 * Avoid to free 'prealloc' if it can be merged with
1006		 * the later extent.
1007		 */
1008		err = insert_state(tree, prealloc, start, this_end,
1009				   NULL, NULL, &bits, changeset);
1010		if (err)
1011			extent_io_tree_panic(tree, err);
1012
1013		cache_state(prealloc, cached_state);
1014		prealloc = NULL;
1015		start = this_end + 1;
1016		goto search_again;
1017	}
1018	/*
1019	 * | ---- desired range ---- |
1020	 *                        | state |
1021	 * We need to split the extent, and set the bit
1022	 * on the first half
1023	 */
1024	if (state->start <= end && state->end > end) {
1025		if (state->state & exclusive_bits) {
1026			*failed_start = start;
1027			err = -EEXIST;
1028			goto out;
1029		}
1030
1031		prealloc = alloc_extent_state_atomic(prealloc);
1032		BUG_ON(!prealloc);
1033		err = split_state(tree, state, prealloc, end + 1);
1034		if (err)
1035			extent_io_tree_panic(tree, err);
1036
1037		set_state_bits(tree, prealloc, &bits, changeset);
1038		cache_state(prealloc, cached_state);
1039		merge_state(tree, prealloc);
1040		prealloc = NULL;
1041		goto out;
1042	}
1043
1044search_again:
1045	if (start > end)
1046		goto out;
1047	spin_unlock(&tree->lock);
1048	if (gfpflags_allow_blocking(mask))
1049		cond_resched();
1050	goto again;
1051
1052out:
1053	spin_unlock(&tree->lock);
1054	if (prealloc)
1055		free_extent_state(prealloc);
1056
1057	return err;
1058
1059}
1060
1061int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1062		   unsigned bits, u64 * failed_start,
1063		   struct extent_state **cached_state, gfp_t mask)
1064{
1065	return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1066				cached_state, mask, NULL);
1067}
1068
1069
1070/**
1071 * convert_extent_bit - convert all bits in a given range from one bit to
1072 * 			another
1073 * @tree:	the io tree to search
1074 * @start:	the start offset in bytes
1075 * @end:	the end offset in bytes (inclusive)
1076 * @bits:	the bits to set in this range
1077 * @clear_bits:	the bits to clear in this range
1078 * @cached_state:	state that we're going to cache
1079 *
1080 * This will go through and set bits for the given range.  If any states exist
1081 * already in this range they are set with the given bit and cleared of the
1082 * clear_bits.  This is only meant to be used by things that are mergeable, ie
1083 * converting from say DELALLOC to DIRTY.  This is not meant to be used with
1084 * boundary bits like LOCK.
1085 *
1086 * All allocations are done with GFP_NOFS.
1087 */
1088int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1089		       unsigned bits, unsigned clear_bits,
1090		       struct extent_state **cached_state)
1091{
1092	struct extent_state *state;
1093	struct extent_state *prealloc = NULL;
1094	struct rb_node *node;
1095	struct rb_node **p;
1096	struct rb_node *parent;
1097	int err = 0;
1098	u64 last_start;
1099	u64 last_end;
1100	bool first_iteration = true;
1101
1102	btrfs_debug_check_extent_io_range(tree, start, end);
1103
1104again:
1105	if (!prealloc) {
1106		/*
1107		 * Best effort, don't worry if extent state allocation fails
1108		 * here for the first iteration. We might have a cached state
1109		 * that matches exactly the target range, in which case no
1110		 * extent state allocations are needed. We'll only know this
1111		 * after locking the tree.
1112		 */
1113		prealloc = alloc_extent_state(GFP_NOFS);
1114		if (!prealloc && !first_iteration)
1115			return -ENOMEM;
1116	}
1117
1118	spin_lock(&tree->lock);
1119	if (cached_state && *cached_state) {
1120		state = *cached_state;
1121		if (state->start <= start && state->end > start &&
1122		    extent_state_in_tree(state)) {
1123			node = &state->rb_node;
1124			goto hit_next;
1125		}
1126	}
1127
1128	/*
1129	 * this search will find all the extents that end after
1130	 * our range starts.
1131	 */
1132	node = tree_search_for_insert(tree, start, &p, &parent);
1133	if (!node) {
1134		prealloc = alloc_extent_state_atomic(prealloc);
1135		if (!prealloc) {
1136			err = -ENOMEM;
1137			goto out;
1138		}
1139		err = insert_state(tree, prealloc, start, end,
1140				   &p, &parent, &bits, NULL);
1141		if (err)
1142			extent_io_tree_panic(tree, err);
1143		cache_state(prealloc, cached_state);
1144		prealloc = NULL;
1145		goto out;
1146	}
1147	state = rb_entry(node, struct extent_state, rb_node);
1148hit_next:
1149	last_start = state->start;
1150	last_end = state->end;
1151
1152	/*
1153	 * | ---- desired range ---- |
1154	 * | state |
1155	 *
1156	 * Just lock what we found and keep going
1157	 */
1158	if (state->start == start && state->end <= end) {
1159		set_state_bits(tree, state, &bits, NULL);
1160		cache_state(state, cached_state);
1161		state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1162		if (last_end == (u64)-1)
1163			goto out;
1164		start = last_end + 1;
1165		if (start < end && state && state->start == start &&
1166		    !need_resched())
1167			goto hit_next;
1168		goto search_again;
1169	}
1170
1171	/*
1172	 *     | ---- desired range ---- |
1173	 * | state |
1174	 *   or
1175	 * | ------------- state -------------- |
1176	 *
1177	 * We need to split the extent we found, and may flip bits on
1178	 * second half.
1179	 *
1180	 * If the extent we found extends past our
1181	 * range, we just split and search again.  It'll get split
1182	 * again the next time though.
1183	 *
1184	 * If the extent we found is inside our range, we set the
1185	 * desired bit on it.
1186	 */
1187	if (state->start < start) {
1188		prealloc = alloc_extent_state_atomic(prealloc);
1189		if (!prealloc) {
1190			err = -ENOMEM;
1191			goto out;
1192		}
1193		err = split_state(tree, state, prealloc, start);
1194		if (err)
1195			extent_io_tree_panic(tree, err);
1196		prealloc = NULL;
1197		if (err)
1198			goto out;
1199		if (state->end <= end) {
1200			set_state_bits(tree, state, &bits, NULL);
1201			cache_state(state, cached_state);
1202			state = clear_state_bit(tree, state, &clear_bits, 0,
1203						NULL);
1204			if (last_end == (u64)-1)
1205				goto out;
1206			start = last_end + 1;
1207			if (start < end && state && state->start == start &&
1208			    !need_resched())
1209				goto hit_next;
1210		}
1211		goto search_again;
1212	}
1213	/*
1214	 * | ---- desired range ---- |
1215	 *     | state | or               | state |
1216	 *
1217	 * There's a hole, we need to insert something in it and
1218	 * ignore the extent we found.
1219	 */
1220	if (state->start > start) {
1221		u64 this_end;
1222		if (end < last_start)
1223			this_end = end;
1224		else
1225			this_end = last_start - 1;
1226
1227		prealloc = alloc_extent_state_atomic(prealloc);
1228		if (!prealloc) {
1229			err = -ENOMEM;
1230			goto out;
1231		}
1232
1233		/*
1234		 * Avoid to free 'prealloc' if it can be merged with
1235		 * the later extent.
1236		 */
1237		err = insert_state(tree, prealloc, start, this_end,
1238				   NULL, NULL, &bits, NULL);
1239		if (err)
1240			extent_io_tree_panic(tree, err);
1241		cache_state(prealloc, cached_state);
1242		prealloc = NULL;
1243		start = this_end + 1;
1244		goto search_again;
1245	}
1246	/*
1247	 * | ---- desired range ---- |
1248	 *                        | state |
1249	 * We need to split the extent, and set the bit
1250	 * on the first half
1251	 */
1252	if (state->start <= end && state->end > end) {
1253		prealloc = alloc_extent_state_atomic(prealloc);
1254		if (!prealloc) {
1255			err = -ENOMEM;
1256			goto out;
1257		}
1258
1259		err = split_state(tree, state, prealloc, end + 1);
1260		if (err)
1261			extent_io_tree_panic(tree, err);
1262
1263		set_state_bits(tree, prealloc, &bits, NULL);
1264		cache_state(prealloc, cached_state);
1265		clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1266		prealloc = NULL;
1267		goto out;
1268	}
1269
1270search_again:
1271	if (start > end)
1272		goto out;
1273	spin_unlock(&tree->lock);
1274	cond_resched();
1275	first_iteration = false;
1276	goto again;
1277
1278out:
1279	spin_unlock(&tree->lock);
1280	if (prealloc)
1281		free_extent_state(prealloc);
1282
1283	return err;
1284}
1285
1286/* wrappers around set/clear extent bit */
1287int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1288			   unsigned bits, struct extent_changeset *changeset)
1289{
1290	/*
1291	 * We don't support EXTENT_LOCKED yet, as current changeset will
1292	 * record any bits changed, so for EXTENT_LOCKED case, it will
1293	 * either fail with -EEXIST or changeset will record the whole
1294	 * range.
1295	 */
1296	BUG_ON(bits & EXTENT_LOCKED);
1297
1298	return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
1299				changeset);
1300}
1301
1302int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1303		     unsigned bits, int wake, int delete,
1304		     struct extent_state **cached, gfp_t mask)
1305{
1306	return __clear_extent_bit(tree, start, end, bits, wake, delete,
1307				  cached, mask, NULL);
1308}
1309
1310int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1311		unsigned bits, struct extent_changeset *changeset)
1312{
1313	/*
1314	 * Don't support EXTENT_LOCKED case, same reason as
1315	 * set_record_extent_bits().
1316	 */
1317	BUG_ON(bits & EXTENT_LOCKED);
1318
1319	return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
1320				  changeset);
1321}
1322
1323/*
1324 * either insert or lock state struct between start and end use mask to tell
1325 * us if waiting is desired.
1326 */
1327int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1328		     struct extent_state **cached_state)
1329{
1330	int err;
1331	u64 failed_start;
1332
1333	while (1) {
1334		err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
1335				       EXTENT_LOCKED, &failed_start,
1336				       cached_state, GFP_NOFS, NULL);
1337		if (err == -EEXIST) {
1338			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1339			start = failed_start;
1340		} else
1341			break;
1342		WARN_ON(start > end);
1343	}
1344	return err;
1345}
1346
1347int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1348{
1349	int err;
1350	u64 failed_start;
1351
1352	err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1353			       &failed_start, NULL, GFP_NOFS, NULL);
1354	if (err == -EEXIST) {
1355		if (failed_start > start)
1356			clear_extent_bit(tree, start, failed_start - 1,
1357					 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1358		return 0;
1359	}
1360	return 1;
1361}
1362
1363void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1364{
1365	unsigned long index = start >> PAGE_SHIFT;
1366	unsigned long end_index = end >> PAGE_SHIFT;
1367	struct page *page;
1368
1369	while (index <= end_index) {
1370		page = find_get_page(inode->i_mapping, index);
1371		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1372		clear_page_dirty_for_io(page);
1373		put_page(page);
1374		index++;
1375	}
1376}
1377
1378void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1379{
1380	unsigned long index = start >> PAGE_SHIFT;
1381	unsigned long end_index = end >> PAGE_SHIFT;
1382	struct page *page;
1383
1384	while (index <= end_index) {
1385		page = find_get_page(inode->i_mapping, index);
1386		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1387		__set_page_dirty_nobuffers(page);
1388		account_page_redirty(page);
1389		put_page(page);
1390		index++;
1391	}
1392}
1393
1394/*
1395 * helper function to set both pages and extents in the tree writeback
1396 */
1397static void set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1398{
1399	unsigned long index = start >> PAGE_SHIFT;
1400	unsigned long end_index = end >> PAGE_SHIFT;
1401	struct page *page;
1402
1403	while (index <= end_index) {
1404		page = find_get_page(tree->mapping, index);
1405		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1406		set_page_writeback(page);
1407		put_page(page);
1408		index++;
1409	}
1410}
1411
1412/* find the first state struct with 'bits' set after 'start', and
1413 * return it.  tree->lock must be held.  NULL will returned if
1414 * nothing was found after 'start'
1415 */
1416static struct extent_state *
1417find_first_extent_bit_state(struct extent_io_tree *tree,
1418			    u64 start, unsigned bits)
1419{
1420	struct rb_node *node;
1421	struct extent_state *state;
1422
1423	/*
1424	 * this search will find all the extents that end after
1425	 * our range starts.
1426	 */
1427	node = tree_search(tree, start);
1428	if (!node)
1429		goto out;
1430
1431	while (1) {
1432		state = rb_entry(node, struct extent_state, rb_node);
1433		if (state->end >= start && (state->state & bits))
1434			return state;
1435
1436		node = rb_next(node);
1437		if (!node)
1438			break;
1439	}
1440out:
1441	return NULL;
1442}
1443
1444/*
1445 * find the first offset in the io tree with 'bits' set. zero is
1446 * returned if we find something, and *start_ret and *end_ret are
1447 * set to reflect the state struct that was found.
1448 *
1449 * If nothing was found, 1 is returned. If found something, return 0.
1450 */
1451int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1452			  u64 *start_ret, u64 *end_ret, unsigned bits,
1453			  struct extent_state **cached_state)
1454{
1455	struct extent_state *state;
1456	struct rb_node *n;
1457	int ret = 1;
1458
1459	spin_lock(&tree->lock);
1460	if (cached_state && *cached_state) {
1461		state = *cached_state;
1462		if (state->end == start - 1 && extent_state_in_tree(state)) {
1463			n = rb_next(&state->rb_node);
1464			while (n) {
1465				state = rb_entry(n, struct extent_state,
1466						 rb_node);
1467				if (state->state & bits)
1468					goto got_it;
1469				n = rb_next(n);
1470			}
1471			free_extent_state(*cached_state);
1472			*cached_state = NULL;
1473			goto out;
1474		}
1475		free_extent_state(*cached_state);
1476		*cached_state = NULL;
1477	}
1478
1479	state = find_first_extent_bit_state(tree, start, bits);
1480got_it:
1481	if (state) {
1482		cache_state_if_flags(state, cached_state, 0);
1483		*start_ret = state->start;
1484		*end_ret = state->end;
1485		ret = 0;
1486	}
1487out:
1488	spin_unlock(&tree->lock);
1489	return ret;
1490}
1491
1492/*
1493 * find a contiguous range of bytes in the file marked as delalloc, not
1494 * more than 'max_bytes'.  start and end are used to return the range,
1495 *
1496 * 1 is returned if we find something, 0 if nothing was in the tree
1497 */
1498static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1499					u64 *start, u64 *end, u64 max_bytes,
1500					struct extent_state **cached_state)
1501{
1502	struct rb_node *node;
1503	struct extent_state *state;
1504	u64 cur_start = *start;
1505	u64 found = 0;
1506	u64 total_bytes = 0;
1507
1508	spin_lock(&tree->lock);
1509
1510	/*
1511	 * this search will find all the extents that end after
1512	 * our range starts.
1513	 */
1514	node = tree_search(tree, cur_start);
1515	if (!node) {
1516		if (!found)
1517			*end = (u64)-1;
1518		goto out;
1519	}
1520
1521	while (1) {
1522		state = rb_entry(node, struct extent_state, rb_node);
1523		if (found && (state->start != cur_start ||
1524			      (state->state & EXTENT_BOUNDARY))) {
1525			goto out;
1526		}
1527		if (!(state->state & EXTENT_DELALLOC)) {
1528			if (!found)
1529				*end = state->end;
1530			goto out;
1531		}
1532		if (!found) {
1533			*start = state->start;
1534			*cached_state = state;
1535			atomic_inc(&state->refs);
1536		}
1537		found++;
1538		*end = state->end;
1539		cur_start = state->end + 1;
1540		node = rb_next(node);
1541		total_bytes += state->end - state->start + 1;
1542		if (total_bytes >= max_bytes)
1543			break;
1544		if (!node)
1545			break;
1546	}
1547out:
1548	spin_unlock(&tree->lock);
1549	return found;
1550}
1551
1552static noinline void __unlock_for_delalloc(struct inode *inode,
1553					   struct page *locked_page,
1554					   u64 start, u64 end)
1555{
1556	int ret;
1557	struct page *pages[16];
1558	unsigned long index = start >> PAGE_SHIFT;
1559	unsigned long end_index = end >> PAGE_SHIFT;
1560	unsigned long nr_pages = end_index - index + 1;
1561	int i;
1562
1563	if (index == locked_page->index && end_index == index)
1564		return;
 
 
 
 
 
 
 
1565
1566	while (nr_pages > 0) {
1567		ret = find_get_pages_contig(inode->i_mapping, index,
1568				     min_t(unsigned long, nr_pages,
1569				     ARRAY_SIZE(pages)), pages);
1570		for (i = 0; i < ret; i++) {
1571			if (pages[i] != locked_page)
1572				unlock_page(pages[i]);
1573			put_page(pages[i]);
1574		}
1575		nr_pages -= ret;
1576		index += ret;
1577		cond_resched();
1578	}
1579}
1580
1581static noinline int lock_delalloc_pages(struct inode *inode,
1582					struct page *locked_page,
1583					u64 delalloc_start,
1584					u64 delalloc_end)
1585{
1586	unsigned long index = delalloc_start >> PAGE_SHIFT;
1587	unsigned long start_index = index;
1588	unsigned long end_index = delalloc_end >> PAGE_SHIFT;
1589	unsigned long pages_locked = 0;
1590	struct page *pages[16];
1591	unsigned long nrpages;
1592	int ret;
1593	int i;
1594
1595	/* the caller is responsible for locking the start index */
1596	if (index == locked_page->index && index == end_index)
1597		return 0;
1598
1599	/* skip the page at the start index */
1600	nrpages = end_index - index + 1;
1601	while (nrpages > 0) {
1602		ret = find_get_pages_contig(inode->i_mapping, index,
1603				     min_t(unsigned long,
1604				     nrpages, ARRAY_SIZE(pages)), pages);
1605		if (ret == 0) {
1606			ret = -EAGAIN;
1607			goto done;
1608		}
1609		/* now we have an array of pages, lock them all */
1610		for (i = 0; i < ret; i++) {
1611			/*
1612			 * the caller is taking responsibility for
1613			 * locked_page
1614			 */
1615			if (pages[i] != locked_page) {
1616				lock_page(pages[i]);
1617				if (!PageDirty(pages[i]) ||
1618				    pages[i]->mapping != inode->i_mapping) {
1619					ret = -EAGAIN;
1620					unlock_page(pages[i]);
1621					put_page(pages[i]);
1622					goto done;
1623				}
1624			}
1625			put_page(pages[i]);
1626			pages_locked++;
1627		}
1628		nrpages -= ret;
1629		index += ret;
1630		cond_resched();
1631	}
1632	ret = 0;
1633done:
1634	if (ret && pages_locked) {
1635		__unlock_for_delalloc(inode, locked_page,
1636			      delalloc_start,
1637			      ((u64)(start_index + pages_locked - 1)) <<
1638			      PAGE_SHIFT);
1639	}
1640	return ret;
1641}
1642
1643/*
1644 * find a contiguous range of bytes in the file marked as delalloc, not
1645 * more than 'max_bytes'.  start and end are used to return the range,
 
 
 
 
 
1646 *
1647 * 1 is returned if we find something, 0 if nothing was in the tree
 
 
 
 
1648 */
1649STATIC u64 find_lock_delalloc_range(struct inode *inode,
1650				    struct extent_io_tree *tree,
1651				    struct page *locked_page, u64 *start,
1652				    u64 *end, u64 max_bytes)
1653{
 
 
 
 
 
 
1654	u64 delalloc_start;
1655	u64 delalloc_end;
1656	u64 found;
1657	struct extent_state *cached_state = NULL;
1658	int ret;
1659	int loops = 0;
1660
 
 
 
 
 
 
1661again:
1662	/* step one, find a bunch of delalloc bytes starting at start */
1663	delalloc_start = *start;
1664	delalloc_end = 0;
1665	found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1666				    max_bytes, &cached_state);
1667	if (!found || delalloc_end <= *start) {
1668		*start = delalloc_start;
1669		*end = delalloc_end;
 
 
1670		free_extent_state(cached_state);
1671		return 0;
1672	}
1673
1674	/*
1675	 * start comes from the offset of locked_page.  We have to lock
1676	 * pages in order, so we can't process delalloc bytes before
1677	 * locked_page
1678	 */
1679	if (delalloc_start < *start)
1680		delalloc_start = *start;
1681
1682	/*
1683	 * make sure to limit the number of pages we try to lock down
1684	 */
1685	if (delalloc_end + 1 - delalloc_start > max_bytes)
1686		delalloc_end = delalloc_start + max_bytes - 1;
1687
1688	/* step two, lock all the pages after the page that has start */
1689	ret = lock_delalloc_pages(inode, locked_page,
1690				  delalloc_start, delalloc_end);
 
1691	if (ret == -EAGAIN) {
1692		/* some of the pages are gone, lets avoid looping by
1693		 * shortening the size of the delalloc range we're searching
1694		 */
1695		free_extent_state(cached_state);
1696		cached_state = NULL;
1697		if (!loops) {
1698			max_bytes = PAGE_SIZE;
1699			loops = 1;
1700			goto again;
1701		} else {
1702			found = 0;
1703			goto out_failed;
1704		}
1705	}
1706	BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1707
1708	/* step three, lock the state bits for the whole range */
1709	lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1710
1711	/* then test to make sure it is all still delalloc */
1712	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1713			     EXTENT_DELALLOC, 1, cached_state);
 
 
1714	if (!ret) {
1715		unlock_extent_cached(tree, delalloc_start, delalloc_end,
1716				     &cached_state, GFP_NOFS);
1717		__unlock_for_delalloc(inode, locked_page,
1718			      delalloc_start, delalloc_end);
1719		cond_resched();
1720		goto again;
1721	}
1722	free_extent_state(cached_state);
1723	*start = delalloc_start;
1724	*end = delalloc_end;
1725out_failed:
1726	return found;
1727}
1728
1729void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1730				 u64 delalloc_end, struct page *locked_page,
1731				 unsigned clear_bits,
1732				 unsigned long page_ops)
1733{
1734	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
1735	int ret;
1736	struct page *pages[16];
1737	unsigned long index = start >> PAGE_SHIFT;
1738	unsigned long end_index = end >> PAGE_SHIFT;
1739	unsigned long nr_pages = end_index - index + 1;
1740	int i;
1741
1742	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1743	if (page_ops == 0)
1744		return;
1745
1746	if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1747		mapping_set_error(inode->i_mapping, -EIO);
1748
1749	while (nr_pages > 0) {
1750		ret = find_get_pages_contig(inode->i_mapping, index,
1751				     min_t(unsigned long,
1752				     nr_pages, ARRAY_SIZE(pages)), pages);
1753		for (i = 0; i < ret; i++) {
1754
1755			if (page_ops & PAGE_SET_PRIVATE2)
1756				SetPagePrivate2(pages[i]);
1757
1758			if (pages[i] == locked_page) {
1759				put_page(pages[i]);
1760				continue;
1761			}
1762			if (page_ops & PAGE_CLEAR_DIRTY)
1763				clear_page_dirty_for_io(pages[i]);
1764			if (page_ops & PAGE_SET_WRITEBACK)
1765				set_page_writeback(pages[i]);
1766			if (page_ops & PAGE_SET_ERROR)
1767				SetPageError(pages[i]);
1768			if (page_ops & PAGE_END_WRITEBACK)
1769				end_page_writeback(pages[i]);
1770			if (page_ops & PAGE_UNLOCK)
1771				unlock_page(pages[i]);
1772			put_page(pages[i]);
1773		}
1774		nr_pages -= ret;
1775		index += ret;
1776		cond_resched();
1777	}
1778}
1779
1780/*
1781 * count the number of bytes in the tree that have a given bit(s)
1782 * set.  This can be fairly slow, except for EXTENT_DIRTY which is
1783 * cached.  The total number found is returned.
1784 */
1785u64 count_range_bits(struct extent_io_tree *tree,
1786		     u64 *start, u64 search_end, u64 max_bytes,
1787		     unsigned bits, int contig)
1788{
1789	struct rb_node *node;
1790	struct extent_state *state;
1791	u64 cur_start = *start;
1792	u64 total_bytes = 0;
1793	u64 last = 0;
1794	int found = 0;
1795
1796	if (WARN_ON(search_end <= cur_start))
1797		return 0;
1798
1799	spin_lock(&tree->lock);
1800	if (cur_start == 0 && bits == EXTENT_DIRTY) {
1801		total_bytes = tree->dirty_bytes;
1802		goto out;
1803	}
1804	/*
1805	 * this search will find all the extents that end after
1806	 * our range starts.
1807	 */
1808	node = tree_search(tree, cur_start);
1809	if (!node)
1810		goto out;
1811
1812	while (1) {
1813		state = rb_entry(node, struct extent_state, rb_node);
1814		if (state->start > search_end)
1815			break;
1816		if (contig && found && state->start > last + 1)
1817			break;
1818		if (state->end >= cur_start && (state->state & bits) == bits) {
1819			total_bytes += min(search_end, state->end) + 1 -
1820				       max(cur_start, state->start);
1821			if (total_bytes >= max_bytes)
1822				break;
1823			if (!found) {
1824				*start = max(cur_start, state->start);
1825				found = 1;
1826			}
1827			last = state->end;
1828		} else if (contig && found) {
1829			break;
1830		}
1831		node = rb_next(node);
1832		if (!node)
1833			break;
1834	}
1835out:
1836	spin_unlock(&tree->lock);
1837	return total_bytes;
1838}
1839
1840/*
1841 * set the private field for a given byte offset in the tree.  If there isn't
1842 * an extent_state there already, this does nothing.
1843 */
1844static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
1845		struct io_failure_record *failrec)
1846{
1847	struct rb_node *node;
1848	struct extent_state *state;
1849	int ret = 0;
1850
1851	spin_lock(&tree->lock);
1852	/*
1853	 * this search will find all the extents that end after
1854	 * our range starts.
1855	 */
1856	node = tree_search(tree, start);
1857	if (!node) {
1858		ret = -ENOENT;
1859		goto out;
1860	}
1861	state = rb_entry(node, struct extent_state, rb_node);
1862	if (state->start != start) {
1863		ret = -ENOENT;
1864		goto out;
1865	}
1866	state->failrec = failrec;
1867out:
1868	spin_unlock(&tree->lock);
1869	return ret;
1870}
1871
1872static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
1873		struct io_failure_record **failrec)
1874{
1875	struct rb_node *node;
1876	struct extent_state *state;
1877	int ret = 0;
1878
1879	spin_lock(&tree->lock);
1880	/*
1881	 * this search will find all the extents that end after
1882	 * our range starts.
1883	 */
1884	node = tree_search(tree, start);
1885	if (!node) {
1886		ret = -ENOENT;
1887		goto out;
1888	}
1889	state = rb_entry(node, struct extent_state, rb_node);
1890	if (state->start != start) {
1891		ret = -ENOENT;
1892		goto out;
1893	}
1894	*failrec = state->failrec;
1895out:
1896	spin_unlock(&tree->lock);
1897	return ret;
1898}
1899
1900/*
1901 * searches a range in the state tree for a given mask.
1902 * If 'filled' == 1, this returns 1 only if every extent in the tree
1903 * has the bits set.  Otherwise, 1 is returned if any bit in the
1904 * range is found set.
1905 */
1906int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1907		   unsigned bits, int filled, struct extent_state *cached)
1908{
1909	struct extent_state *state = NULL;
1910	struct rb_node *node;
1911	int bitset = 0;
1912
1913	spin_lock(&tree->lock);
1914	if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1915	    cached->end > start)
1916		node = &cached->rb_node;
1917	else
1918		node = tree_search(tree, start);
1919	while (node && start <= end) {
1920		state = rb_entry(node, struct extent_state, rb_node);
1921
1922		if (filled && state->start > start) {
1923			bitset = 0;
1924			break;
1925		}
1926
1927		if (state->start > end)
1928			break;
1929
1930		if (state->state & bits) {
1931			bitset = 1;
1932			if (!filled)
1933				break;
1934		} else if (filled) {
1935			bitset = 0;
1936			break;
1937		}
1938
1939		if (state->end == (u64)-1)
1940			break;
1941
1942		start = state->end + 1;
1943		if (start > end)
1944			break;
1945		node = rb_next(node);
1946		if (!node) {
1947			if (filled)
1948				bitset = 0;
1949			break;
1950		}
1951	}
1952	spin_unlock(&tree->lock);
1953	return bitset;
1954}
1955
1956/*
1957 * helper function to set a given page up to date if all the
1958 * extents in the tree for that page are up to date
1959 */
1960static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1961{
1962	u64 start = page_offset(page);
1963	u64 end = start + PAGE_SIZE - 1;
1964	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1965		SetPageUptodate(page);
1966}
1967
1968int free_io_failure(struct inode *inode, struct io_failure_record *rec)
1969{
1970	int ret;
1971	int err = 0;
1972	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1973
1974	set_state_failrec(failure_tree, rec->start, NULL);
1975	ret = clear_extent_bits(failure_tree, rec->start,
1976				rec->start + rec->len - 1,
1977				EXTENT_LOCKED | EXTENT_DIRTY);
1978	if (ret)
1979		err = ret;
1980
1981	ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
1982				rec->start + rec->len - 1,
1983				EXTENT_DAMAGED);
1984	if (ret && !err)
1985		err = ret;
1986
1987	kfree(rec);
1988	return err;
1989}
1990
1991/*
1992 * this bypasses the standard btrfs submit functions deliberately, as
1993 * the standard behavior is to write all copies in a raid setup. here we only
1994 * want to write the one bad copy. so we do the mapping for ourselves and issue
1995 * submit_bio directly.
1996 * to avoid any synchronization issues, wait for the data after writing, which
1997 * actually prevents the read that triggered the error from finishing.
1998 * currently, there can be no more than two copies of every data bit. thus,
1999 * exactly one rewrite is required.
2000 */
2001int repair_io_failure(struct inode *inode, u64 start, u64 length, u64 logical,
2002		      struct page *page, unsigned int pg_offset, int mirror_num)
2003{
2004	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2005	struct bio *bio;
2006	struct btrfs_device *dev;
2007	u64 map_length = 0;
2008	u64 sector;
2009	struct btrfs_bio *bbio = NULL;
2010	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2011	int ret;
2012
2013	ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2014	BUG_ON(!mirror_num);
2015
2016	/* we can't repair anything in raid56 yet */
2017	if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
2018		return 0;
2019
2020	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2021	if (!bio)
2022		return -EIO;
2023	bio->bi_iter.bi_size = 0;
2024	map_length = length;
2025
2026	/*
2027	 * Avoid races with device replace and make sure our bbio has devices
2028	 * associated to its stripes that don't go away while we are doing the
2029	 * read repair operation.
2030	 */
2031	btrfs_bio_counter_inc_blocked(fs_info);
2032	ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
2033			      &map_length, &bbio, mirror_num);
2034	if (ret) {
2035		btrfs_bio_counter_dec(fs_info);
2036		bio_put(bio);
2037		return -EIO;
2038	}
2039	BUG_ON(mirror_num != bbio->mirror_num);
2040	sector = bbio->stripes[mirror_num-1].physical >> 9;
2041	bio->bi_iter.bi_sector = sector;
2042	dev = bbio->stripes[mirror_num-1].dev;
2043	btrfs_put_bbio(bbio);
2044	if (!dev || !dev->bdev || !dev->writeable) {
2045		btrfs_bio_counter_dec(fs_info);
2046		bio_put(bio);
2047		return -EIO;
2048	}
2049	bio->bi_bdev = dev->bdev;
2050	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
2051	bio_add_page(bio, page, length, pg_offset);
2052
2053	if (btrfsic_submit_bio_wait(bio)) {
2054		/* try to remap that extent elsewhere? */
2055		btrfs_bio_counter_dec(fs_info);
2056		bio_put(bio);
2057		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2058		return -EIO;
2059	}
2060
2061	btrfs_info_rl_in_rcu(fs_info,
2062		"read error corrected: ino %llu off %llu (dev %s sector %llu)",
2063				  btrfs_ino(inode), start,
2064				  rcu_str_deref(dev->name), sector);
2065	btrfs_bio_counter_dec(fs_info);
2066	bio_put(bio);
2067	return 0;
2068}
2069
2070int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
2071			 struct extent_buffer *eb, int mirror_num)
2072{
2073	u64 start = eb->start;
2074	unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2075	int ret = 0;
2076
2077	if (fs_info->sb->s_flags & MS_RDONLY)
2078		return -EROFS;
2079
2080	for (i = 0; i < num_pages; i++) {
2081		struct page *p = eb->pages[i];
2082
2083		ret = repair_io_failure(fs_info->btree_inode, start,
2084					PAGE_SIZE, start, p,
2085					start - page_offset(p), mirror_num);
2086		if (ret)
2087			break;
2088		start += PAGE_SIZE;
2089	}
2090
2091	return ret;
 
2092}
2093
2094/*
2095 * each time an IO finishes, we do a fast check in the IO failure tree
2096 * to see if we need to process or clean up an io_failure_record
 
 
 
 
 
 
 
 
2097 */
2098int clean_io_failure(struct inode *inode, u64 start, struct page *page,
2099		     unsigned int pg_offset)
2100{
2101	u64 private;
2102	struct io_failure_record *failrec;
2103	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2104	struct extent_state *state;
2105	int num_copies;
2106	int ret;
 
 
 
 
 
 
 
2107
2108	private = 0;
2109	ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
2110				(u64)-1, 1, EXTENT_DIRTY, 0);
2111	if (!ret)
2112		return 0;
 
2113
2114	ret = get_state_failrec(&BTRFS_I(inode)->io_failure_tree, start,
2115			&failrec);
2116	if (ret)
2117		return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2118
2119	BUG_ON(!failrec->this_mirror);
 
 
2120
2121	if (failrec->in_validation) {
2122		/* there was no real error, just free the record */
2123		btrfs_debug(fs_info,
2124			"clean_io_failure: freeing dummy error at %llu",
2125			failrec->start);
2126		goto out;
2127	}
2128	if (fs_info->sb->s_flags & MS_RDONLY)
2129		goto out;
 
 
 
 
 
2130
2131	spin_lock(&BTRFS_I(inode)->io_tree.lock);
2132	state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
2133					    failrec->start,
2134					    EXTENT_LOCKED);
2135	spin_unlock(&BTRFS_I(inode)->io_tree.lock);
2136
2137	if (state && state->start <= failrec->start &&
2138	    state->end >= failrec->start + failrec->len - 1) {
2139		num_copies = btrfs_num_copies(fs_info, failrec->logical,
2140					      failrec->len);
2141		if (num_copies > 1)  {
2142			repair_io_failure(inode, start, failrec->len,
2143					  failrec->logical, page,
2144					  pg_offset, failrec->failed_mirror);
2145		}
2146	}
2147
2148out:
2149	free_io_failure(inode, failrec);
2150
2151	return 0;
 
 
 
2152}
2153
2154/*
2155 * Can be called when
2156 * - hold extent lock
2157 * - under ordered extent
2158 * - the inode is freeing
 
 
 
 
 
2159 */
2160void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
2161{
2162	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2163	struct io_failure_record *failrec;
2164	struct extent_state *state, *next;
2165
2166	if (RB_EMPTY_ROOT(&failure_tree->state))
2167		return;
2168
2169	spin_lock(&failure_tree->lock);
2170	state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2171	while (state) {
2172		if (state->start > end)
2173			break;
2174
2175		ASSERT(state->end <= end);
2176
2177		next = next_state(state);
2178
2179		failrec = state->failrec;
2180		free_extent_state(state);
2181		kfree(failrec);
2182
2183		state = next;
2184	}
2185	spin_unlock(&failure_tree->lock);
2186}
2187
2188int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2189		struct io_failure_record **failrec_ret)
2190{
2191	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2192	struct io_failure_record *failrec;
2193	struct extent_map *em;
2194	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2195	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2196	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2197	int ret;
2198	u64 logical;
2199
2200	ret = get_state_failrec(failure_tree, start, &failrec);
2201	if (ret) {
2202		failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2203		if (!failrec)
 
 
 
 
 
 
 
 
 
 
 
 
2204			return -ENOMEM;
2205
2206		failrec->start = start;
2207		failrec->len = end - start + 1;
2208		failrec->this_mirror = 0;
2209		failrec->bio_flags = 0;
2210		failrec->in_validation = 0;
2211
2212		read_lock(&em_tree->lock);
2213		em = lookup_extent_mapping(em_tree, start, failrec->len);
2214		if (!em) {
2215			read_unlock(&em_tree->lock);
2216			kfree(failrec);
2217			return -EIO;
2218		}
2219
2220		if (em->start > start || em->start + em->len <= start) {
2221			free_extent_map(em);
2222			em = NULL;
2223		}
2224		read_unlock(&em_tree->lock);
2225		if (!em) {
2226			kfree(failrec);
2227			return -EIO;
2228		}
2229
2230		logical = start - em->start;
2231		logical = em->block_start + logical;
2232		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2233			logical = em->block_start;
2234			failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2235			extent_set_compress_type(&failrec->bio_flags,
2236						 em->compress_type);
2237		}
2238
2239		btrfs_debug(fs_info,
2240			"Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2241			logical, start, failrec->len);
2242
2243		failrec->logical = logical;
2244		free_extent_map(em);
2245
2246		/* set the bits in the private failure tree */
2247		ret = set_extent_bits(failure_tree, start, end,
2248					EXTENT_LOCKED | EXTENT_DIRTY);
2249		if (ret >= 0)
2250			ret = set_state_failrec(failure_tree, start, failrec);
2251		/* set the bits in the inode's tree */
2252		if (ret >= 0)
2253			ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
2254		if (ret < 0) {
2255			kfree(failrec);
2256			return ret;
2257		}
2258	} else {
2259		btrfs_debug(fs_info,
2260			"Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2261			failrec->logical, failrec->start, failrec->len,
2262			failrec->in_validation);
2263		/*
2264		 * when data can be on disk more than twice, add to failrec here
2265		 * (e.g. with a list for failed_mirror) to make
2266		 * clean_io_failure() clean all those errors at once.
2267		 */
2268	}
2269
2270	*failrec_ret = failrec;
2271
2272	return 0;
2273}
2274
2275int btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
2276			   struct io_failure_record *failrec, int failed_mirror)
2277{
2278	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2279	int num_copies;
2280
2281	num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
2282	if (num_copies == 1) {
2283		/*
2284		 * we only have a single copy of the data, so don't bother with
2285		 * all the retry and error correction code that follows. no
2286		 * matter what the error is, it is very likely to persist.
2287		 */
2288		btrfs_debug(fs_info,
2289			"Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2290			num_copies, failrec->this_mirror, failed_mirror);
2291		return 0;
2292	}
2293
2294	/*
2295	 * there are two premises:
2296	 *	a) deliver good data to the caller
2297	 *	b) correct the bad sectors on disk
2298	 */
2299	if (failed_bio->bi_vcnt > 1) {
2300		/*
2301		 * to fulfill b), we need to know the exact failing sectors, as
2302		 * we don't want to rewrite any more than the failed ones. thus,
2303		 * we need separate read requests for the failed bio
2304		 *
2305		 * if the following BUG_ON triggers, our validation request got
2306		 * merged. we need separate requests for our algorithm to work.
2307		 */
2308		BUG_ON(failrec->in_validation);
2309		failrec->in_validation = 1;
2310		failrec->this_mirror = failed_mirror;
2311	} else {
2312		/*
2313		 * we're ready to fulfill a) and b) alongside. get a good copy
2314		 * of the failed sector and if we succeed, we have setup
2315		 * everything for repair_io_failure to do the rest for us.
2316		 */
2317		if (failrec->in_validation) {
2318			BUG_ON(failrec->this_mirror != failed_mirror);
2319			failrec->in_validation = 0;
2320			failrec->this_mirror = 0;
2321		}
2322		failrec->failed_mirror = failed_mirror;
2323		failrec->this_mirror++;
2324		if (failrec->this_mirror == failed_mirror)
2325			failrec->this_mirror++;
2326	}
2327
2328	if (failrec->this_mirror > num_copies) {
2329		btrfs_debug(fs_info,
2330			"Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2331			num_copies, failrec->this_mirror, failed_mirror);
2332		return 0;
2333	}
2334
2335	return 1;
2336}
2337
2338
2339struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2340				    struct io_failure_record *failrec,
2341				    struct page *page, int pg_offset, int icsum,
2342				    bio_end_io_t *endio_func, void *data)
2343{
2344	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2345	struct bio *bio;
2346	struct btrfs_io_bio *btrfs_failed_bio;
2347	struct btrfs_io_bio *btrfs_bio;
2348
2349	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2350	if (!bio)
2351		return NULL;
2352
2353	bio->bi_end_io = endio_func;
2354	bio->bi_iter.bi_sector = failrec->logical >> 9;
2355	bio->bi_bdev = fs_info->fs_devices->latest_bdev;
2356	bio->bi_iter.bi_size = 0;
2357	bio->bi_private = data;
2358
2359	btrfs_failed_bio = btrfs_io_bio(failed_bio);
2360	if (btrfs_failed_bio->csum) {
2361		u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2362
2363		btrfs_bio = btrfs_io_bio(bio);
2364		btrfs_bio->csum = btrfs_bio->csum_inline;
2365		icsum *= csum_size;
2366		memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2367		       csum_size);
2368	}
2369
2370	bio_add_page(bio, page, failrec->len, pg_offset);
2371
2372	return bio;
2373}
2374
2375/*
2376 * this is a generic handler for readpage errors (default
2377 * readpage_io_failed_hook). if other copies exist, read those and write back
2378 * good data to the failed position. does not investigate in remapping the
2379 * failed extent elsewhere, hoping the device will be smart enough to do this as
2380 * needed
2381 */
2382
2383static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2384			      struct page *page, u64 start, u64 end,
2385			      int failed_mirror)
2386{
2387	struct io_failure_record *failrec;
2388	struct inode *inode = page->mapping->host;
2389	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2390	struct bio *bio;
2391	int read_mode = 0;
2392	int ret;
2393
2394	BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
2395
2396	ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2397	if (ret)
2398		return ret;
2399
2400	ret = btrfs_check_repairable(inode, failed_bio, failrec, failed_mirror);
2401	if (!ret) {
2402		free_io_failure(inode, failrec);
2403		return -EIO;
2404	}
2405
2406	if (failed_bio->bi_vcnt > 1)
2407		read_mode |= REQ_FAILFAST_DEV;
2408
2409	phy_offset >>= inode->i_sb->s_blocksize_bits;
2410	bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2411				      start - page_offset(page),
2412				      (int)phy_offset, failed_bio->bi_end_io,
2413				      NULL);
2414	if (!bio) {
2415		free_io_failure(inode, failrec);
2416		return -EIO;
2417	}
2418	bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
2419
2420	btrfs_debug(btrfs_sb(inode->i_sb),
2421		"Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
2422		read_mode, failrec->this_mirror, failrec->in_validation);
2423
2424	ret = tree->ops->submit_bio_hook(inode, bio, failrec->this_mirror,
2425					 failrec->bio_flags, 0);
2426	if (ret) {
2427		free_io_failure(inode, failrec);
2428		bio_put(bio);
2429	}
2430
2431	return ret;
2432}
2433
2434/* lots and lots of room for performance fixes in the end_bio funcs */
 
 
 
 
 
 
 
2435
2436void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2437{
2438	int uptodate = (err == 0);
2439	struct extent_io_tree *tree;
2440	int ret = 0;
2441
2442	tree = &BTRFS_I(page->mapping->host)->io_tree;
2443
2444	if (tree->ops && tree->ops->writepage_end_io_hook) {
2445		ret = tree->ops->writepage_end_io_hook(page, start,
2446					       end, NULL, uptodate);
2447		if (ret)
2448			uptodate = 0;
2449	}
2450
2451	if (!uptodate) {
2452		ClearPageUptodate(page);
2453		SetPageError(page);
2454		ret = ret < 0 ? ret : -EIO;
2455		mapping_set_error(page->mapping, ret);
2456	}
2457}
2458
2459/*
2460 * after a writepage IO is done, we need to:
2461 * clear the uptodate bits on error
2462 * clear the writeback bits in the extent tree for this IO
2463 * end_page_writeback if the page has no more pending IO
2464 *
2465 * Scheduling is not allowed, so the extent state tree is expected
2466 * to have one and only one object corresponding to this IO.
2467 */
2468static void end_bio_extent_writepage(struct bio *bio)
2469{
2470	struct bio_vec *bvec;
2471	u64 start;
2472	u64 end;
2473	int i;
2474
2475	bio_for_each_segment_all(bvec, bio, i) {
2476		struct page *page = bvec->bv_page;
2477		struct inode *inode = page->mapping->host;
2478		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2479
2480		/* We always issue full-page reads, but if some block
2481		 * in a page fails to read, blk_update_request() will
2482		 * advance bv_offset and adjust bv_len to compensate.
2483		 * Print a warning for nonzero offsets, and an error
2484		 * if they don't add up to a full page.  */
2485		if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2486			if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2487				btrfs_err(fs_info,
2488				   "partial page write in btrfs with offset %u and length %u",
2489					bvec->bv_offset, bvec->bv_len);
2490			else
2491				btrfs_info(fs_info,
2492				   "incomplete page write in btrfs with offset %u and length %u",
2493					bvec->bv_offset, bvec->bv_len);
 
 
 
 
 
 
2494		}
2495
2496		start = page_offset(page);
2497		end = start + bvec->bv_offset + bvec->bv_len - 1;
2498
2499		end_extent_writepage(page, bio->bi_error, start, end);
2500		end_page_writeback(page);
 
 
 
2501	}
2502
2503	bio_put(bio);
2504}
2505
2506static void
2507endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2508			      int uptodate)
2509{
2510	struct extent_state *cached = NULL;
2511	u64 end = start + len - 1;
2512
2513	if (uptodate && tree->track_uptodate)
2514		set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2515	unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
2516}
2517
2518/*
2519 * after a readpage IO is done, we need to:
2520 * clear the uptodate bits on error
2521 * set the uptodate bits if things worked
2522 * set the page up to date if all extents in the tree are uptodate
2523 * clear the lock bit in the extent tree
2524 * unlock the page if there are no other extents locked for it
2525 *
2526 * Scheduling is not allowed, so the extent state tree is expected
2527 * to have one and only one object corresponding to this IO.
2528 */
2529static void end_bio_extent_readpage(struct bio *bio)
2530{
2531	struct bio_vec *bvec;
2532	int uptodate = !bio->bi_error;
2533	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2534	struct extent_io_tree *tree;
2535	u64 offset = 0;
2536	u64 start;
2537	u64 end;
2538	u64 len;
2539	u64 extent_start = 0;
2540	u64 extent_len = 0;
2541	int mirror;
2542	int ret;
2543	int i;
2544
2545	bio_for_each_segment_all(bvec, bio, i) {
2546		struct page *page = bvec->bv_page;
2547		struct inode *inode = page->mapping->host;
2548		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2549
2550		btrfs_debug(fs_info,
2551			"end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2552			(u64)bio->bi_iter.bi_sector, bio->bi_error,
2553			io_bio->mirror_num);
2554		tree = &BTRFS_I(inode)->io_tree;
2555
2556		/* We always issue full-page reads, but if some block
2557		 * in a page fails to read, blk_update_request() will
2558		 * advance bv_offset and adjust bv_len to compensate.
2559		 * Print a warning for nonzero offsets, and an error
2560		 * if they don't add up to a full page.  */
2561		if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2562			if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2563				btrfs_err(fs_info,
2564					"partial page read in btrfs with offset %u and length %u",
2565					bvec->bv_offset, bvec->bv_len);
2566			else
2567				btrfs_info(fs_info,
2568					"incomplete page read in btrfs with offset %u and length %u",
2569					bvec->bv_offset, bvec->bv_len);
2570		}
2571
2572		start = page_offset(page);
2573		end = start + bvec->bv_offset + bvec->bv_len - 1;
2574		len = bvec->bv_len;
2575
2576		mirror = io_bio->mirror_num;
2577		if (likely(uptodate && tree->ops &&
2578			   tree->ops->readpage_end_io_hook)) {
2579			ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2580							      page, start, end,
2581							      mirror);
2582			if (ret)
2583				uptodate = 0;
2584			else
2585				clean_io_failure(inode, start, page, 0);
2586		}
2587
2588		if (likely(uptodate))
2589			goto readpage_ok;
2590
2591		if (tree->ops && tree->ops->readpage_io_failed_hook) {
2592			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2593			if (!ret && !bio->bi_error)
2594				uptodate = 1;
2595		} else {
2596			/*
2597			 * The generic bio_readpage_error handles errors the
2598			 * following way: If possible, new read requests are
2599			 * created and submitted and will end up in
2600			 * end_bio_extent_readpage as well (if we're lucky, not
2601			 * in the !uptodate case). In that case it returns 0 and
2602			 * we just go on with the next page in our bio. If it
2603			 * can't handle the error it will return -EIO and we
2604			 * remain responsible for that page.
2605			 */
2606			ret = bio_readpage_error(bio, offset, page, start, end,
2607						 mirror);
2608			if (ret == 0) {
2609				uptodate = !bio->bi_error;
2610				offset += len;
2611				continue;
2612			}
2613		}
2614readpage_ok:
2615		if (likely(uptodate)) {
2616			loff_t i_size = i_size_read(inode);
2617			pgoff_t end_index = i_size >> PAGE_SHIFT;
2618			unsigned off;
2619
2620			/* Zero out the end if this page straddles i_size */
2621			off = i_size & (PAGE_SIZE-1);
2622			if (page->index == end_index && off)
2623				zero_user_segment(page, off, PAGE_SIZE);
2624			SetPageUptodate(page);
2625		} else {
2626			ClearPageUptodate(page);
2627			SetPageError(page);
2628		}
2629		unlock_page(page);
2630		offset += len;
2631
2632		if (unlikely(!uptodate)) {
2633			if (extent_len) {
2634				endio_readpage_release_extent(tree,
2635							      extent_start,
2636							      extent_len, 1);
2637				extent_start = 0;
2638				extent_len = 0;
2639			}
2640			endio_readpage_release_extent(tree, start,
2641						      end - start + 1, 0);
2642		} else if (!extent_len) {
2643			extent_start = start;
2644			extent_len = end + 1 - start;
2645		} else if (extent_start + extent_len == start) {
2646			extent_len += end + 1 - start;
2647		} else {
2648			endio_readpage_release_extent(tree, extent_start,
2649						      extent_len, uptodate);
2650			extent_start = start;
2651			extent_len = end + 1 - start;
2652		}
2653	}
2654
2655	if (extent_len)
2656		endio_readpage_release_extent(tree, extent_start, extent_len,
2657					      uptodate);
2658	if (io_bio->end_io)
2659		io_bio->end_io(io_bio, bio->bi_error);
2660	bio_put(bio);
2661}
2662
2663/*
2664 * this allocates from the btrfs_bioset.  We're returning a bio right now
2665 * but you can call btrfs_io_bio for the appropriate container_of magic
2666 */
2667struct bio *
2668btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
2669		gfp_t gfp_flags)
2670{
2671	struct btrfs_io_bio *btrfs_bio;
2672	struct bio *bio;
2673
2674	bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
 
 
 
 
 
 
2675
2676	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2677		while (!bio && (nr_vecs /= 2)) {
2678			bio = bio_alloc_bioset(gfp_flags,
2679					       nr_vecs, btrfs_bioset);
2680		}
2681	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2682
2683	if (bio) {
2684		bio->bi_bdev = bdev;
2685		bio->bi_iter.bi_sector = first_sector;
2686		btrfs_bio = btrfs_io_bio(bio);
2687		btrfs_bio->csum = NULL;
2688		btrfs_bio->csum_allocated = NULL;
2689		btrfs_bio->end_io = NULL;
2690	}
2691	return bio;
2692}
2693
2694struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
 
 
2695{
2696	struct btrfs_io_bio *btrfs_bio;
2697	struct bio *new;
2698
2699	new = bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
2700	if (new) {
2701		btrfs_bio = btrfs_io_bio(new);
2702		btrfs_bio->csum = NULL;
2703		btrfs_bio->csum_allocated = NULL;
2704		btrfs_bio->end_io = NULL;
 
 
 
 
 
 
 
 
 
2705	}
2706	return new;
2707}
2708
2709/* this also allocates from the btrfs_bioset */
2710struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
2711{
2712	struct btrfs_io_bio *btrfs_bio;
2713	struct bio *bio;
2714
2715	bio = bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
2716	if (bio) {
2717		btrfs_bio = btrfs_io_bio(bio);
2718		btrfs_bio->csum = NULL;
2719		btrfs_bio->csum_allocated = NULL;
2720		btrfs_bio->end_io = NULL;
2721	}
2722	return bio;
2723}
2724
2725
2726static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
2727				       unsigned long bio_flags)
2728{
2729	int ret = 0;
2730	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2731	struct page *page = bvec->bv_page;
2732	struct extent_io_tree *tree = bio->bi_private;
2733	u64 start;
2734
2735	start = page_offset(page) + bvec->bv_offset;
2736
2737	bio->bi_private = NULL;
2738	bio_get(bio);
2739
2740	if (tree->ops && tree->ops->submit_bio_hook)
2741		ret = tree->ops->submit_bio_hook(page->mapping->host, bio,
2742					   mirror_num, bio_flags, start);
2743	else
2744		btrfsic_submit_bio(bio);
2745
2746	bio_put(bio);
2747	return ret;
2748}
2749
2750static int merge_bio(struct extent_io_tree *tree, struct page *page,
2751		     unsigned long offset, size_t size, struct bio *bio,
2752		     unsigned long bio_flags)
2753{
2754	int ret = 0;
2755	if (tree->ops && tree->ops->merge_bio_hook)
2756		ret = tree->ops->merge_bio_hook(page, offset, size, bio,
2757						bio_flags);
2758	return ret;
2759
2760}
2761
2762static int submit_extent_page(int op, int op_flags, struct extent_io_tree *tree,
2763			      struct writeback_control *wbc,
2764			      struct page *page, sector_t sector,
2765			      size_t size, unsigned long offset,
2766			      struct block_device *bdev,
2767			      struct bio **bio_ret,
2768			      unsigned long max_pages,
2769			      bio_end_io_t end_io_func,
2770			      int mirror_num,
2771			      unsigned long prev_bio_flags,
2772			      unsigned long bio_flags,
2773			      bool force_bio_submit)
2774{
2775	int ret = 0;
2776	struct bio *bio;
2777	int contig = 0;
2778	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2779	size_t page_size = min_t(size_t, size, PAGE_SIZE);
2780
2781	if (bio_ret && *bio_ret) {
2782		bio = *bio_ret;
2783		if (old_compressed)
2784			contig = bio->bi_iter.bi_sector == sector;
2785		else
2786			contig = bio_end_sector(bio) == sector;
2787
2788		if (prev_bio_flags != bio_flags || !contig ||
2789		    force_bio_submit ||
2790		    merge_bio(tree, page, offset, page_size, bio, bio_flags) ||
2791		    bio_add_page(bio, page, page_size, offset) < page_size) {
2792			ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
2793			if (ret < 0) {
2794				*bio_ret = NULL;
2795				return ret;
2796			}
2797			bio = NULL;
2798		} else {
2799			if (wbc)
2800				wbc_account_io(wbc, page, page_size);
2801			return 0;
2802		}
2803	}
2804
2805	bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES,
2806			GFP_NOFS | __GFP_HIGH);
2807	if (!bio)
2808		return -ENOMEM;
2809
2810	bio_add_page(bio, page, page_size, offset);
2811	bio->bi_end_io = end_io_func;
2812	bio->bi_private = tree;
2813	bio_set_op_attrs(bio, op, op_flags);
2814	if (wbc) {
2815		wbc_init_bio(wbc, bio);
2816		wbc_account_io(wbc, page, page_size);
2817	}
2818
2819	if (bio_ret)
2820		*bio_ret = bio;
2821	else
2822		ret = submit_one_bio(bio, mirror_num, bio_flags);
2823
2824	return ret;
 
2825}
2826
2827static void attach_extent_buffer_page(struct extent_buffer *eb,
2828				      struct page *page)
2829{
2830	if (!PagePrivate(page)) {
2831		SetPagePrivate(page);
2832		get_page(page);
2833		set_page_private(page, (unsigned long)eb);
2834	} else {
2835		WARN_ON(page->private != (unsigned long)eb);
2836	}
2837}
2838
2839void set_page_extent_mapped(struct page *page)
2840{
2841	if (!PagePrivate(page)) {
2842		SetPagePrivate(page);
2843		get_page(page);
2844		set_page_private(page, EXTENT_PAGE_PRIVATE);
2845	}
 
 
 
2846}
2847
2848static struct extent_map *
2849__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
2850		 u64 start, u64 len, get_extent_t *get_extent,
2851		 struct extent_map **em_cached)
2852{
2853	struct extent_map *em;
2854
2855	if (em_cached && *em_cached) {
 
 
2856		em = *em_cached;
2857		if (extent_map_in_tree(em) && start >= em->start &&
2858		    start < extent_map_end(em)) {
2859			atomic_inc(&em->refs);
2860			return em;
2861		}
2862
2863		free_extent_map(em);
2864		*em_cached = NULL;
2865	}
2866
2867	em = get_extent(inode, page, pg_offset, start, len, 0);
2868	if (em_cached && !IS_ERR_OR_NULL(em)) {
2869		BUG_ON(*em_cached);
2870		atomic_inc(&em->refs);
2871		*em_cached = em;
2872	}
 
2873	return em;
2874}
2875/*
2876 * basic readpage implementation.  Locked extent state structs are inserted
2877 * into the tree that are removed when the IO is done (by the end_io
2878 * handlers)
2879 * XXX JDM: This needs looking at to ensure proper page locking
2880 * return 0 on success, otherwise return error
2881 */
2882static int __do_readpage(struct extent_io_tree *tree,
2883			 struct page *page,
2884			 get_extent_t *get_extent,
2885			 struct extent_map **em_cached,
2886			 struct bio **bio, int mirror_num,
2887			 unsigned long *bio_flags, int read_flags,
2888			 u64 *prev_em_start)
2889{
2890	struct inode *inode = page->mapping->host;
2891	u64 start = page_offset(page);
2892	u64 page_end = start + PAGE_SIZE - 1;
2893	u64 end;
2894	u64 cur = start;
2895	u64 extent_offset;
2896	u64 last_byte = i_size_read(inode);
2897	u64 block_start;
2898	u64 cur_end;
2899	sector_t sector;
2900	struct extent_map *em;
2901	struct block_device *bdev;
2902	int ret = 0;
2903	int nr = 0;
2904	size_t pg_offset = 0;
2905	size_t iosize;
2906	size_t disk_io_size;
2907	size_t blocksize = inode->i_sb->s_blocksize;
2908	unsigned long this_bio_flag = 0;
2909
2910	set_page_extent_mapped(page);
2911
2912	end = page_end;
2913	if (!PageUptodate(page)) {
2914		if (cleancache_get_page(page) == 0) {
2915			BUG_ON(blocksize != PAGE_SIZE);
2916			unlock_extent(tree, start, end);
2917			goto out;
2918		}
2919	}
2920
2921	if (page->index == last_byte >> PAGE_SHIFT) {
2922		char *userpage;
2923		size_t zero_offset = last_byte & (PAGE_SIZE - 1);
2924
2925		if (zero_offset) {
2926			iosize = PAGE_SIZE - zero_offset;
2927			userpage = kmap_atomic(page);
2928			memset(userpage + zero_offset, 0, iosize);
2929			flush_dcache_page(page);
2930			kunmap_atomic(userpage);
2931		}
2932	}
 
 
2933	while (cur <= end) {
2934		unsigned long pnr = (last_byte >> PAGE_SHIFT) + 1;
2935		bool force_bio_submit = false;
 
2936
 
2937		if (cur >= last_byte) {
2938			char *userpage;
2939			struct extent_state *cached = NULL;
2940
2941			iosize = PAGE_SIZE - pg_offset;
2942			userpage = kmap_atomic(page);
2943			memset(userpage + pg_offset, 0, iosize);
2944			flush_dcache_page(page);
2945			kunmap_atomic(userpage);
2946			set_extent_uptodate(tree, cur, cur + iosize - 1,
2947					    &cached, GFP_NOFS);
2948			unlock_extent_cached(tree, cur,
2949					     cur + iosize - 1,
2950					     &cached, GFP_NOFS);
2951			break;
2952		}
2953		em = __get_extent_map(inode, page, pg_offset, cur,
2954				      end - cur + 1, get_extent, em_cached);
2955		if (IS_ERR_OR_NULL(em)) {
2956			SetPageError(page);
2957			unlock_extent(tree, cur, end);
2958			break;
2959		}
2960		extent_offset = cur - em->start;
2961		BUG_ON(extent_map_end(em) <= cur);
2962		BUG_ON(end < cur);
2963
2964		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2965			this_bio_flag |= EXTENT_BIO_COMPRESSED;
2966			extent_set_compress_type(&this_bio_flag,
2967						 em->compress_type);
2968		}
2969
2970		iosize = min(extent_map_end(em) - cur, end - cur + 1);
2971		cur_end = min(extent_map_end(em) - 1, end);
2972		iosize = ALIGN(iosize, blocksize);
2973		if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2974			disk_io_size = em->block_len;
2975			sector = em->block_start >> 9;
2976		} else {
2977			sector = (em->block_start + extent_offset) >> 9;
2978			disk_io_size = iosize;
2979		}
2980		bdev = em->bdev;
2981		block_start = em->block_start;
2982		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2983			block_start = EXTENT_MAP_HOLE;
2984
2985		/*
2986		 * If we have a file range that points to a compressed extent
2987		 * and it's followed by a consecutive file range that points to
2988		 * to the same compressed extent (possibly with a different
2989		 * offset and/or length, so it either points to the whole extent
2990		 * or only part of it), we must make sure we do not submit a
2991		 * single bio to populate the pages for the 2 ranges because
2992		 * this makes the compressed extent read zero out the pages
2993		 * belonging to the 2nd range. Imagine the following scenario:
2994		 *
2995		 *  File layout
2996		 *  [0 - 8K]                     [8K - 24K]
2997		 *    |                               |
2998		 *    |                               |
2999		 * points to extent X,         points to extent X,
3000		 * offset 4K, length of 8K     offset 0, length 16K
3001		 *
3002		 * [extent X, compressed length = 4K uncompressed length = 16K]
3003		 *
3004		 * If the bio to read the compressed extent covers both ranges,
3005		 * it will decompress extent X into the pages belonging to the
3006		 * first range and then it will stop, zeroing out the remaining
3007		 * pages that belong to the other range that points to extent X.
3008		 * So here we make sure we submit 2 bios, one for the first
3009		 * range and another one for the third range. Both will target
3010		 * the same physical extent from disk, but we can't currently
3011		 * make the compressed bio endio callback populate the pages
3012		 * for both ranges because each compressed bio is tightly
3013		 * coupled with a single extent map, and each range can have
3014		 * an extent map with a different offset value relative to the
3015		 * uncompressed data of our extent and different lengths. This
3016		 * is a corner case so we prioritize correctness over
3017		 * non-optimal behavior (submitting 2 bios for the same extent).
3018		 */
3019		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3020		    prev_em_start && *prev_em_start != (u64)-1 &&
3021		    *prev_em_start != em->orig_start)
3022			force_bio_submit = true;
3023
3024		if (prev_em_start)
3025			*prev_em_start = em->orig_start;
3026
3027		free_extent_map(em);
3028		em = NULL;
3029
3030		/* we've found a hole, just zero and go on */
3031		if (block_start == EXTENT_MAP_HOLE) {
3032			char *userpage;
3033			struct extent_state *cached = NULL;
3034
3035			userpage = kmap_atomic(page);
3036			memset(userpage + pg_offset, 0, iosize);
3037			flush_dcache_page(page);
3038			kunmap_atomic(userpage);
3039
3040			set_extent_uptodate(tree, cur, cur + iosize - 1,
3041					    &cached, GFP_NOFS);
3042			unlock_extent_cached(tree, cur,
3043					     cur + iosize - 1,
3044					     &cached, GFP_NOFS);
3045			cur = cur + iosize;
3046			pg_offset += iosize;
3047			continue;
3048		}
3049		/* the get_extent function already copied into the page */
3050		if (test_range_bit(tree, cur, cur_end,
3051				   EXTENT_UPTODATE, 1, NULL)) {
3052			check_page_uptodate(tree, page);
3053			unlock_extent(tree, cur, cur + iosize - 1);
3054			cur = cur + iosize;
3055			pg_offset += iosize;
3056			continue;
3057		}
3058		/* we have an inline extent but it didn't get marked up
3059		 * to date.  Error out
3060		 */
3061		if (block_start == EXTENT_MAP_INLINE) {
3062			SetPageError(page);
3063			unlock_extent(tree, cur, cur + iosize - 1);
3064			cur = cur + iosize;
3065			pg_offset += iosize;
3066			continue;
3067		}
3068
3069		pnr -= page->index;
3070		ret = submit_extent_page(REQ_OP_READ, read_flags, tree, NULL,
3071					 page, sector, disk_io_size, pg_offset,
3072					 bdev, bio, pnr,
3073					 end_bio_extent_readpage, mirror_num,
3074					 *bio_flags,
3075					 this_bio_flag,
3076					 force_bio_submit);
3077		if (!ret) {
3078			nr++;
3079			*bio_flags = this_bio_flag;
3080		} else {
3081			SetPageError(page);
3082			unlock_extent(tree, cur, cur + iosize - 1);
3083			goto out;
3084		}
 
 
 
 
 
3085		cur = cur + iosize;
3086		pg_offset += iosize;
3087	}
3088out:
3089	if (!nr) {
3090		if (!PageError(page))
3091			SetPageUptodate(page);
3092		unlock_page(page);
3093	}
3094	return ret;
3095}
3096
3097static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
3098					     struct page *pages[], int nr_pages,
3099					     u64 start, u64 end,
3100					     get_extent_t *get_extent,
3101					     struct extent_map **em_cached,
3102					     struct bio **bio, int mirror_num,
3103					     unsigned long *bio_flags,
3104					     u64 *prev_em_start)
3105{
3106	struct inode *inode;
3107	struct btrfs_ordered_extent *ordered;
3108	int index;
3109
3110	inode = pages[0]->mapping->host;
3111	while (1) {
3112		lock_extent(tree, start, end);
3113		ordered = btrfs_lookup_ordered_range(inode, start,
3114						     end - start + 1);
3115		if (!ordered)
3116			break;
3117		unlock_extent(tree, start, end);
3118		btrfs_start_ordered_extent(inode, ordered, 1);
3119		btrfs_put_ordered_extent(ordered);
3120	}
3121
3122	for (index = 0; index < nr_pages; index++) {
3123		__do_readpage(tree, pages[index], get_extent, em_cached, bio,
3124			      mirror_num, bio_flags, 0, prev_em_start);
3125		put_page(pages[index]);
3126	}
3127}
3128
3129static void __extent_readpages(struct extent_io_tree *tree,
3130			       struct page *pages[],
3131			       int nr_pages, get_extent_t *get_extent,
3132			       struct extent_map **em_cached,
3133			       struct bio **bio, int mirror_num,
3134			       unsigned long *bio_flags,
3135			       u64 *prev_em_start)
3136{
3137	u64 start = 0;
3138	u64 end = 0;
3139	u64 page_start;
3140	int index;
3141	int first_index = 0;
3142
3143	for (index = 0; index < nr_pages; index++) {
3144		page_start = page_offset(pages[index]);
3145		if (!end) {
3146			start = page_start;
3147			end = start + PAGE_SIZE - 1;
3148			first_index = index;
3149		} else if (end + 1 == page_start) {
3150			end += PAGE_SIZE;
3151		} else {
3152			__do_contiguous_readpages(tree, &pages[first_index],
3153						  index - first_index, start,
3154						  end, get_extent, em_cached,
3155						  bio, mirror_num, bio_flags,
3156						  prev_em_start);
3157			start = page_start;
3158			end = start + PAGE_SIZE - 1;
3159			first_index = index;
3160		}
3161	}
3162
3163	if (end)
3164		__do_contiguous_readpages(tree, &pages[first_index],
3165					  index - first_index, start,
3166					  end, get_extent, em_cached, bio,
3167					  mirror_num, bio_flags,
3168					  prev_em_start);
3169}
3170
3171static int __extent_read_full_page(struct extent_io_tree *tree,
3172				   struct page *page,
3173				   get_extent_t *get_extent,
3174				   struct bio **bio, int mirror_num,
3175				   unsigned long *bio_flags, int read_flags)
3176{
3177	struct inode *inode = page->mapping->host;
3178	struct btrfs_ordered_extent *ordered;
3179	u64 start = page_offset(page);
3180	u64 end = start + PAGE_SIZE - 1;
3181	int ret;
3182
3183	while (1) {
3184		lock_extent(tree, start, end);
3185		ordered = btrfs_lookup_ordered_range(inode, start,
3186						PAGE_SIZE);
3187		if (!ordered)
3188			break;
3189		unlock_extent(tree, start, end);
3190		btrfs_start_ordered_extent(inode, ordered, 1);
3191		btrfs_put_ordered_extent(ordered);
3192	}
3193
3194	ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3195			    bio_flags, read_flags, NULL);
3196	return ret;
3197}
3198
3199int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3200			    get_extent_t *get_extent, int mirror_num)
3201{
3202	struct bio *bio = NULL;
3203	unsigned long bio_flags = 0;
3204	int ret;
3205
3206	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3207				      &bio_flags, 0);
3208	if (bio)
3209		ret = submit_one_bio(bio, mirror_num, bio_flags);
3210	return ret;
3211}
3212
3213static void update_nr_written(struct page *page, struct writeback_control *wbc,
3214			      unsigned long nr_written)
3215{
3216	wbc->nr_to_write -= nr_written;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3217}
3218
3219/*
3220 * helper for __extent_writepage, doing all of the delayed allocation setup.
3221 *
3222 * This returns 1 if our fill_delalloc function did all the work required
3223 * to write the page (copy into inline extent).  In this case the IO has
3224 * been started and the page is already unlocked.
3225 *
3226 * This returns 0 if all went well (page still locked)
3227 * This returns < 0 if there were errors (page still locked)
3228 */
3229static noinline_for_stack int writepage_delalloc(struct inode *inode,
3230			      struct page *page, struct writeback_control *wbc,
3231			      struct extent_page_data *epd,
3232			      u64 delalloc_start,
3233			      unsigned long *nr_written)
3234{
3235	struct extent_io_tree *tree = epd->tree;
3236	u64 page_end = delalloc_start + PAGE_SIZE - 1;
3237	u64 nr_delalloc;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3238	u64 delalloc_to_write = 0;
3239	u64 delalloc_end = 0;
3240	int ret;
3241	int page_started = 0;
3242
3243	if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
3244		return 0;
 
 
 
 
 
 
 
 
3245
3246	while (delalloc_end < page_end) {
3247		nr_delalloc = find_lock_delalloc_range(inode, tree,
3248					       page,
3249					       &delalloc_start,
3250					       &delalloc_end,
3251					       BTRFS_MAX_EXTENT_SIZE);
3252		if (nr_delalloc == 0) {
 
3253			delalloc_start = delalloc_end + 1;
3254			continue;
3255		}
3256		ret = tree->ops->fill_delalloc(inode, page,
3257					       delalloc_start,
3258					       delalloc_end,
3259					       &page_started,
3260					       nr_written);
3261		/* File system has been set read-only */
3262		if (ret) {
3263			SetPageError(page);
3264			/* fill_delalloc should be return < 0 for error
3265			 * but just in case, we use > 0 here meaning the
3266			 * IO is started, so we don't want to return > 0
3267			 * unless things are going well.
 
 
 
 
 
 
 
 
 
3268			 */
3269			ret = ret < 0 ? ret : -EIO;
3270			goto done;
 
 
 
 
3271		}
 
 
3272		/*
3273		 * delalloc_end is already one less than the total length, so
3274		 * we don't subtract one from PAGE_SIZE
 
3275		 */
3276		delalloc_to_write += (delalloc_end - delalloc_start +
3277				      PAGE_SIZE) >> PAGE_SHIFT;
3278		delalloc_start = delalloc_end + 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3279	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3280	if (wbc->nr_to_write < delalloc_to_write) {
3281		int thresh = 8192;
3282
3283		if (delalloc_to_write < thresh * 2)
3284			thresh = delalloc_to_write;
3285		wbc->nr_to_write = min_t(u64, delalloc_to_write,
3286					 thresh);
3287	}
3288
3289	/* did the fill delalloc function already unlock and start
3290	 * the IO?
3291	 */
3292	if (page_started) {
3293		/*
3294		 * we've unlocked the page, so we can't update
3295		 * the mapping's writeback index, just update
3296		 * nr_to_write.
3297		 */
3298		wbc->nr_to_write -= *nr_written;
3299		return 1;
3300	}
 
 
 
 
 
 
 
 
 
3301
3302	ret = 0;
3303
3304done:
3305	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3306}
3307
3308/*
3309 * helper for __extent_writepage.  This calls the writepage start hooks,
3310 * and does the loop to map the page into extents and bios.
3311 *
3312 * We return 1 if the IO is started and the page is unlocked,
3313 * 0 if all went well (page still locked)
3314 * < 0 if there were errors (page still locked)
3315 */
3316static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3317				 struct page *page,
3318				 struct writeback_control *wbc,
3319				 struct extent_page_data *epd,
3320				 loff_t i_size,
3321				 unsigned long nr_written,
3322				 int write_flags, int *nr_ret)
3323{
3324	struct extent_io_tree *tree = epd->tree;
3325	u64 start = page_offset(page);
3326	u64 page_end = start + PAGE_SIZE - 1;
3327	u64 end;
3328	u64 cur = start;
3329	u64 extent_offset;
3330	u64 block_start;
3331	u64 iosize;
3332	sector_t sector;
3333	struct extent_state *cached_state = NULL;
3334	struct extent_map *em;
3335	struct block_device *bdev;
3336	size_t pg_offset = 0;
3337	size_t blocksize;
3338	int ret = 0;
3339	int nr = 0;
3340	bool compressed;
3341
3342	if (tree->ops && tree->ops->writepage_start_hook) {
3343		ret = tree->ops->writepage_start_hook(page, start,
3344						      page_end);
3345		if (ret) {
3346			/* Fixup worker will requeue */
3347			if (ret == -EBUSY)
3348				wbc->pages_skipped++;
3349			else
3350				redirty_page_for_writepage(wbc, page);
3351
3352			update_nr_written(page, wbc, nr_written);
3353			unlock_page(page);
3354			ret = 1;
3355			goto done_unlocked;
3356		}
 
3357	}
3358
3359	/*
3360	 * we don't want to touch the inode after unlocking the page,
3361	 * so we update the mapping writeback index now
3362	 */
3363	update_nr_written(page, wbc, nr_written + 1);
3364
3365	end = page_end;
3366	if (i_size <= start) {
3367		if (tree->ops && tree->ops->writepage_end_io_hook)
3368			tree->ops->writepage_end_io_hook(page, start,
3369							 page_end, NULL, 1);
3370		goto done;
3371	}
3372
3373	blocksize = inode->i_sb->s_blocksize;
3374
3375	while (cur <= end) {
3376		u64 em_end;
3377		unsigned long max_nr;
3378
3379		if (cur >= i_size) {
3380			if (tree->ops && tree->ops->writepage_end_io_hook)
3381				tree->ops->writepage_end_io_hook(page, cur,
3382							 page_end, NULL, 1);
3383			break;
3384		}
3385		em = epd->get_extent(inode, page, pg_offset, cur,
3386				     end - cur + 1, 1);
3387		if (IS_ERR_OR_NULL(em)) {
3388			SetPageError(page);
3389			ret = PTR_ERR_OR_ZERO(em);
 
 
3390			break;
3391		}
3392
3393		extent_offset = cur - em->start;
3394		em_end = extent_map_end(em);
3395		BUG_ON(em_end <= cur);
3396		BUG_ON(end < cur);
3397		iosize = min(em_end - cur, end - cur + 1);
3398		iosize = ALIGN(iosize, blocksize);
3399		sector = (em->block_start + extent_offset) >> 9;
3400		bdev = em->bdev;
3401		block_start = em->block_start;
3402		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3403		free_extent_map(em);
3404		em = NULL;
3405
3406		/*
3407		 * compressed and inline extents are written through other
3408		 * paths in the FS
3409		 */
3410		if (compressed || block_start == EXTENT_MAP_HOLE ||
3411		    block_start == EXTENT_MAP_INLINE) {
3412			/*
3413			 * end_io notification does not happen here for
3414			 * compressed extents
 
3415			 */
3416			if (!compressed && tree->ops &&
3417			    tree->ops->writepage_end_io_hook)
3418				tree->ops->writepage_end_io_hook(page, cur,
3419							 cur + iosize - 1,
3420							 NULL, 1);
3421			else if (compressed) {
3422				/* we don't want to end_page_writeback on
3423				 * a compressed extent.  this happens
3424				 * elsewhere
3425				 */
3426				nr++;
3427			}
3428
3429			cur += iosize;
3430			pg_offset += iosize;
3431			continue;
3432		}
3433
3434		max_nr = (i_size >> PAGE_SHIFT) + 1;
3435
3436		set_range_writeback(tree, cur, cur + iosize - 1);
3437		if (!PageWriteback(page)) {
3438			btrfs_err(BTRFS_I(inode)->root->fs_info,
3439				   "page %lu not writeback, cur %llu end %llu",
3440			       page->index, cur, end);
3441		}
3442
3443		ret = submit_extent_page(REQ_OP_WRITE, write_flags, tree, wbc,
3444					 page, sector, iosize, pg_offset,
3445					 bdev, &epd->bio, max_nr,
3446					 end_bio_extent_writepage,
3447					 0, 0, 0, false);
3448		if (ret)
3449			SetPageError(page);
3450
3451		cur = cur + iosize;
3452		pg_offset += iosize;
3453		nr++;
3454	}
3455done:
3456	*nr_ret = nr;
3457
3458done_unlocked:
3459
3460	/* drop our reference on any cached states */
3461	free_extent_state(cached_state);
 
 
 
 
 
 
 
 
 
 
 
 
 
3462	return ret;
3463}
3464
3465/*
3466 * the writepage semantics are similar to regular writepage.  extent
3467 * records are inserted to lock ranges in the tree, and as dirty areas
3468 * are found, they are marked writeback.  Then the lock bits are removed
3469 * and the end_io handler clears the writeback ranges
 
 
 
3470 */
3471static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3472			      void *data)
3473{
3474	struct inode *inode = page->mapping->host;
3475	struct extent_page_data *epd = data;
3476	u64 start = page_offset(page);
3477	u64 page_end = start + PAGE_SIZE - 1;
3478	int ret;
3479	int nr = 0;
3480	size_t pg_offset = 0;
3481	loff_t i_size = i_size_read(inode);
3482	unsigned long end_index = i_size >> PAGE_SHIFT;
3483	int write_flags = 0;
3484	unsigned long nr_written = 0;
3485
3486	if (wbc->sync_mode == WB_SYNC_ALL)
3487		write_flags = REQ_SYNC;
3488
3489	trace___extent_writepage(page, inode, wbc);
3490
3491	WARN_ON(!PageLocked(page));
3492
3493	ClearPageError(page);
3494
3495	pg_offset = i_size & (PAGE_SIZE - 1);
3496	if (page->index > end_index ||
3497	   (page->index == end_index && !pg_offset)) {
3498		page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3499		unlock_page(page);
3500		return 0;
3501	}
3502
3503	if (page->index == end_index) {
3504		char *userpage;
3505
3506		userpage = kmap_atomic(page);
3507		memset(userpage + pg_offset, 0,
3508		       PAGE_SIZE - pg_offset);
3509		kunmap_atomic(userpage);
3510		flush_dcache_page(page);
3511	}
3512
3513	pg_offset = 0;
3514
3515	set_page_extent_mapped(page);
 
 
 
 
 
 
 
3516
3517	ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
3518	if (ret == 1)
3519		goto done_unlocked;
3520	if (ret)
3521		goto done;
3522
3523	ret = __extent_writepage_io(inode, page, wbc, epd,
3524				    i_size, nr_written, write_flags, &nr);
3525	if (ret == 1)
3526		goto done_unlocked;
 
 
3527
3528done:
3529	if (nr == 0) {
3530		/* make sure the mapping tag for page dirty gets cleared */
3531		set_page_writeback(page);
3532		end_page_writeback(page);
3533	}
3534	if (PageError(page)) {
3535		ret = ret < 0 ? ret : -EIO;
3536		end_extent_writepage(page, ret, start, page_end);
3537	}
3538	unlock_page(page);
3539	return ret;
3540
3541done_unlocked:
3542	return 0;
3543}
3544
3545void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3546{
3547	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3548		       TASK_UNINTERRUPTIBLE);
3549}
3550
3551static noinline_for_stack int
3552lock_extent_buffer_for_io(struct extent_buffer *eb,
3553			  struct btrfs_fs_info *fs_info,
3554			  struct extent_page_data *epd)
 
 
 
 
 
3555{
3556	unsigned long i, num_pages;
3557	int flush = 0;
3558	int ret = 0;
3559
3560	if (!btrfs_try_tree_write_lock(eb)) {
3561		flush = 1;
3562		flush_write_bio(epd);
3563		btrfs_tree_lock(eb);
3564	}
3565
3566	if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
 
3567		btrfs_tree_unlock(eb);
3568		if (!epd->sync_io)
3569			return 0;
3570		if (!flush) {
3571			flush_write_bio(epd);
3572			flush = 1;
3573		}
3574		while (1) {
3575			wait_on_extent_buffer_writeback(eb);
3576			btrfs_tree_lock(eb);
3577			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3578				break;
3579			btrfs_tree_unlock(eb);
3580		}
3581	}
3582
3583	/*
3584	 * We need to do this to prevent races in people who check if the eb is
3585	 * under IO since we can end up having no IO bits set for a short period
3586	 * of time.
3587	 */
3588	spin_lock(&eb->refs_lock);
3589	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3590		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3591		spin_unlock(&eb->refs_lock);
3592		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3593		__percpu_counter_add(&fs_info->dirty_metadata_bytes,
3594				     -eb->len,
3595				     fs_info->dirty_metadata_batch);
3596		ret = 1;
3597	} else {
3598		spin_unlock(&eb->refs_lock);
3599	}
3600
3601	btrfs_tree_unlock(eb);
3602
3603	if (!ret)
3604		return ret;
3605
3606	num_pages = num_extent_pages(eb->start, eb->len);
3607	for (i = 0; i < num_pages; i++) {
3608		struct page *p = eb->pages[i];
3609
3610		if (!trylock_page(p)) {
3611			if (!flush) {
3612				flush_write_bio(epd);
3613				flush = 1;
3614			}
3615			lock_page(p);
3616		}
3617	}
3618
3619	return ret;
3620}
3621
3622static void end_extent_buffer_writeback(struct extent_buffer *eb)
3623{
3624	clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3625	smp_mb__after_atomic();
3626	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3627}
3628
3629static void set_btree_ioerr(struct page *page)
3630{
3631	struct extent_buffer *eb = (struct extent_buffer *)page->private;
3632
3633	SetPageError(page);
3634	if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3635		return;
 
 
 
 
 
 
 
 
 
 
3636
3637	/*
3638	 * If writeback for a btree extent that doesn't belong to a log tree
3639	 * failed, increment the counter transaction->eb_write_errors.
3640	 * We do this because while the transaction is running and before it's
3641	 * committing (when we call filemap_fdata[write|wait]_range against
3642	 * the btree inode), we might have
3643	 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3644	 * returns an error or an error happens during writeback, when we're
3645	 * committing the transaction we wouldn't know about it, since the pages
3646	 * can be no longer dirty nor marked anymore for writeback (if a
3647	 * subsequent modification to the extent buffer didn't happen before the
3648	 * transaction commit), which makes filemap_fdata[write|wait]_range not
3649	 * able to find the pages tagged with SetPageError at transaction
3650	 * commit time. So if this happens we must abort the transaction,
3651	 * otherwise we commit a super block with btree roots that point to
3652	 * btree nodes/leafs whose content on disk is invalid - either garbage
3653	 * or the content of some node/leaf from a past generation that got
3654	 * cowed or deleted and is no longer valid.
3655	 *
3656	 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3657	 * not be enough - we need to distinguish between log tree extents vs
3658	 * non-log tree extents, and the next filemap_fdatawait_range() call
3659	 * will catch and clear such errors in the mapping - and that call might
3660	 * be from a log sync and not from a transaction commit. Also, checking
3661	 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3662	 * not done and would not be reliable - the eb might have been released
3663	 * from memory and reading it back again means that flag would not be
3664	 * set (since it's a runtime flag, not persisted on disk).
3665	 *
3666	 * Using the flags below in the btree inode also makes us achieve the
3667	 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3668	 * writeback for all dirty pages and before filemap_fdatawait_range()
3669	 * is called, the writeback for all dirty pages had already finished
3670	 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3671	 * filemap_fdatawait_range() would return success, as it could not know
3672	 * that writeback errors happened (the pages were no longer tagged for
3673	 * writeback).
3674	 */
3675	switch (eb->log_index) {
3676	case -1:
3677		set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
3678		break;
3679	case 0:
3680		set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
3681		break;
3682	case 1:
3683		set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
3684		break;
3685	default:
3686		BUG(); /* unexpected, logic error */
3687	}
3688}
3689
3690static void end_bio_extent_buffer_writepage(struct bio *bio)
 
 
 
 
 
3691{
3692	struct bio_vec *bvec;
3693	struct extent_buffer *eb;
3694	int i, done;
3695
3696	bio_for_each_segment_all(bvec, bio, i) {
3697		struct page *page = bvec->bv_page;
3698
3699		eb = (struct extent_buffer *)page->private;
3700		BUG_ON(!eb);
3701		done = atomic_dec_and_test(&eb->io_pages);
3702
3703		if (bio->bi_error ||
3704		    test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3705			ClearPageUptodate(page);
3706			set_btree_ioerr(page);
3707		}
3708
3709		end_page_writeback(page);
 
 
 
 
 
 
 
 
 
3710
3711		if (!done)
3712			continue;
 
 
 
 
 
 
 
 
 
 
 
 
 
3713
3714		end_extent_buffer_writeback(eb);
 
3715	}
3716
3717	bio_put(bio);
 
 
 
 
3718}
3719
3720static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3721			struct btrfs_fs_info *fs_info,
3722			struct writeback_control *wbc,
3723			struct extent_page_data *epd)
3724{
3725	struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3726	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3727	u64 offset = eb->start;
3728	u32 nritems;
3729	unsigned long i, num_pages;
3730	unsigned long bio_flags = 0;
3731	unsigned long start, end;
3732	int write_flags = (epd->sync_io ? REQ_SYNC : 0) | REQ_META;
3733	int ret = 0;
3734
3735	clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3736	num_pages = num_extent_pages(eb->start, eb->len);
3737	atomic_set(&eb->io_pages, num_pages);
3738	if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
3739		bio_flags = EXTENT_BIO_TREE_LOG;
3740
3741	/* set btree blocks beyond nritems with 0 to avoid stale content. */
3742	nritems = btrfs_header_nritems(eb);
3743	if (btrfs_header_level(eb) > 0) {
3744		end = btrfs_node_key_ptr_offset(nritems);
3745
3746		memzero_extent_buffer(eb, end, eb->len - end);
3747	} else {
3748		/*
3749		 * leaf:
3750		 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
3751		 */
3752		start = btrfs_item_nr_offset(nritems);
3753		end = btrfs_leaf_data(eb) + leaf_data_end(fs_info, eb);
 
 
 
 
3754		memzero_extent_buffer(eb, start, end - start);
3755	}
 
3756
3757	for (i = 0; i < num_pages; i++) {
3758		struct page *p = eb->pages[i];
 
 
 
3759
3760		clear_page_dirty_for_io(p);
3761		set_page_writeback(p);
3762		ret = submit_extent_page(REQ_OP_WRITE, write_flags, tree, wbc,
3763					 p, offset >> 9, PAGE_SIZE, 0, bdev,
3764					 &epd->bio, -1,
3765					 end_bio_extent_buffer_writepage,
3766					 0, epd->bio_flags, bio_flags, false);
3767		epd->bio_flags = bio_flags;
3768		if (ret) {
3769			set_btree_ioerr(p);
3770			end_page_writeback(p);
3771			if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3772				end_extent_buffer_writeback(eb);
3773			ret = -EIO;
3774			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3775		}
3776		offset += PAGE_SIZE;
3777		update_nr_written(p, wbc, 1);
3778		unlock_page(p);
3779	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3780
3781	if (unlikely(ret)) {
3782		for (; i < num_pages; i++) {
3783			struct page *p = eb->pages[i];
3784			clear_page_dirty_for_io(p);
3785			unlock_page(p);
 
 
 
 
 
 
3786		}
 
3787	}
 
 
3788
3789	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3790}
3791
3792int btree_write_cache_pages(struct address_space *mapping,
3793				   struct writeback_control *wbc)
3794{
3795	struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3796	struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3797	struct extent_buffer *eb, *prev_eb = NULL;
3798	struct extent_page_data epd = {
3799		.bio = NULL,
3800		.tree = tree,
3801		.extent_locked = 0,
3802		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3803		.bio_flags = 0,
3804	};
3805	int ret = 0;
3806	int done = 0;
3807	int nr_to_write_done = 0;
3808	struct pagevec pvec;
3809	int nr_pages;
3810	pgoff_t index;
3811	pgoff_t end;		/* Inclusive */
3812	int scanned = 0;
3813	int tag;
3814
3815	pagevec_init(&pvec, 0);
3816	if (wbc->range_cyclic) {
3817		index = mapping->writeback_index; /* Start from prev offset */
3818		end = -1;
 
 
 
 
 
3819	} else {
3820		index = wbc->range_start >> PAGE_SHIFT;
3821		end = wbc->range_end >> PAGE_SHIFT;
3822		scanned = 1;
3823	}
3824	if (wbc->sync_mode == WB_SYNC_ALL)
3825		tag = PAGECACHE_TAG_TOWRITE;
3826	else
3827		tag = PAGECACHE_TAG_DIRTY;
 
3828retry:
3829	if (wbc->sync_mode == WB_SYNC_ALL)
3830		tag_pages_for_writeback(mapping, index, end);
3831	while (!done && !nr_to_write_done && (index <= end) &&
3832	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3833			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3834		unsigned i;
3835
3836		scanned = 1;
3837		for (i = 0; i < nr_pages; i++) {
3838			struct page *page = pvec.pages[i];
3839
3840			if (!PagePrivate(page))
3841				continue;
3842
3843			if (!wbc->range_cyclic && page->index > end) {
3844				done = 1;
3845				break;
3846			}
3847
3848			spin_lock(&mapping->private_lock);
3849			if (!PagePrivate(page)) {
3850				spin_unlock(&mapping->private_lock);
3851				continue;
3852			}
3853
3854			eb = (struct extent_buffer *)page->private;
3855
3856			/*
3857			 * Shouldn't happen and normally this would be a BUG_ON
3858			 * but no sense in crashing the users box for something
3859			 * we can survive anyway.
3860			 */
3861			if (WARN_ON(!eb)) {
3862				spin_unlock(&mapping->private_lock);
3863				continue;
3864			}
3865
3866			if (eb == prev_eb) {
3867				spin_unlock(&mapping->private_lock);
3868				continue;
3869			}
3870
3871			ret = atomic_inc_not_zero(&eb->refs);
3872			spin_unlock(&mapping->private_lock);
3873			if (!ret)
3874				continue;
3875
3876			prev_eb = eb;
3877			ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3878			if (!ret) {
3879				free_extent_buffer(eb);
3880				continue;
3881			}
3882
3883			ret = write_one_eb(eb, fs_info, wbc, &epd);
3884			if (ret) {
3885				done = 1;
3886				free_extent_buffer(eb);
3887				break;
3888			}
3889			free_extent_buffer(eb);
3890
3891			/*
3892			 * the filesystem may choose to bump up nr_to_write.
3893			 * We have to make sure to honor the new nr_to_write
3894			 * at any time
3895			 */
3896			nr_to_write_done = wbc->nr_to_write <= 0;
3897		}
3898		pagevec_release(&pvec);
3899		cond_resched();
3900	}
3901	if (!scanned && !done) {
3902		/*
3903		 * We hit the last page and there is more work to be done: wrap
3904		 * back to the start of the file
3905		 */
3906		scanned = 1;
3907		index = 0;
3908		goto retry;
3909	}
3910	flush_write_bio(&epd);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3911	return ret;
3912}
3913
3914/**
3915 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3916 * @mapping: address space structure to write
3917 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3918 * @writepage: function called for each page
3919 * @data: data passed to writepage function
3920 *
3921 * If a page is already under I/O, write_cache_pages() skips it, even
3922 * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
3923 * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
3924 * and msync() need to guarantee that all the data which was dirty at the time
3925 * the call was made get new I/O started against them.  If wbc->sync_mode is
3926 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3927 * existing IO to complete.
3928 */
3929static int extent_write_cache_pages(struct extent_io_tree *tree,
3930			     struct address_space *mapping,
3931			     struct writeback_control *wbc,
3932			     writepage_t writepage, void *data,
3933			     void (*flush_fn)(void *))
3934{
 
3935	struct inode *inode = mapping->host;
3936	int ret = 0;
3937	int done = 0;
3938	int nr_to_write_done = 0;
3939	struct pagevec pvec;
3940	int nr_pages;
3941	pgoff_t index;
3942	pgoff_t end;		/* Inclusive */
3943	pgoff_t done_index;
3944	int range_whole = 0;
3945	int scanned = 0;
3946	int tag;
3947
3948	/*
3949	 * We have to hold onto the inode so that ordered extents can do their
3950	 * work when the IO finishes.  The alternative to this is failing to add
3951	 * an ordered extent if the igrab() fails there and that is a huge pain
3952	 * to deal with, so instead just hold onto the inode throughout the
3953	 * writepages operation.  If it fails here we are freeing up the inode
3954	 * anyway and we'd rather not waste our time writing out stuff that is
3955	 * going to be truncated anyway.
3956	 */
3957	if (!igrab(inode))
3958		return 0;
3959
3960	pagevec_init(&pvec, 0);
3961	if (wbc->range_cyclic) {
3962		index = mapping->writeback_index; /* Start from prev offset */
3963		end = -1;
 
 
 
 
 
3964	} else {
3965		index = wbc->range_start >> PAGE_SHIFT;
3966		end = wbc->range_end >> PAGE_SHIFT;
3967		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
3968			range_whole = 1;
3969		scanned = 1;
3970	}
3971	if (wbc->sync_mode == WB_SYNC_ALL)
 
 
 
 
 
 
 
 
 
 
 
 
 
3972		tag = PAGECACHE_TAG_TOWRITE;
3973	else
3974		tag = PAGECACHE_TAG_DIRTY;
3975retry:
3976	if (wbc->sync_mode == WB_SYNC_ALL)
3977		tag_pages_for_writeback(mapping, index, end);
3978	done_index = index;
3979	while (!done && !nr_to_write_done && (index <= end) &&
3980	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3981			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3982		unsigned i;
3983
3984		scanned = 1;
3985		for (i = 0; i < nr_pages; i++) {
3986			struct page *page = pvec.pages[i];
3987
3988			done_index = page->index;
3989			/*
3990			 * At this point we hold neither mapping->tree_lock nor
3991			 * lock on the page itself: the page may be truncated or
3992			 * invalidated (changing page->mapping to NULL), or even
3993			 * swizzled back from swapper_space to tmpfs file
3994			 * mapping
3995			 */
3996			if (!trylock_page(page)) {
3997				flush_fn(data);
3998				lock_page(page);
3999			}
4000
4001			if (unlikely(page->mapping != mapping)) {
4002				unlock_page(page);
4003				continue;
4004			}
4005
4006			if (!wbc->range_cyclic && page->index > end) {
4007				done = 1;
4008				unlock_page(page);
4009				continue;
4010			}
4011
4012			if (wbc->sync_mode != WB_SYNC_NONE) {
4013				if (PageWriteback(page))
4014					flush_fn(data);
4015				wait_on_page_writeback(page);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4016			}
4017
4018			if (PageWriteback(page) ||
4019			    !clear_page_dirty_for_io(page)) {
4020				unlock_page(page);
4021				continue;
4022			}
4023
4024			ret = (*writepage)(page, wbc, data);
4025
4026			if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
4027				unlock_page(page);
4028				ret = 0;
4029			}
4030			if (ret < 0) {
4031				/*
4032				 * done_index is set past this page,
4033				 * so media errors will not choke
4034				 * background writeout for the entire
4035				 * file. This has consequences for
4036				 * range_cyclic semantics (ie. it may
4037				 * not be suitable for data integrity
4038				 * writeout).
4039				 */
4040				done_index = page->index + 1;
4041				done = 1;
4042				break;
4043			}
4044
4045			/*
4046			 * the filesystem may choose to bump up nr_to_write.
4047			 * We have to make sure to honor the new nr_to_write
4048			 * at any time
4049			 */
4050			nr_to_write_done = wbc->nr_to_write <= 0;
 
4051		}
4052		pagevec_release(&pvec);
4053		cond_resched();
4054	}
4055	if (!scanned && !done) {
4056		/*
4057		 * We hit the last page and there is more work to be done: wrap
4058		 * back to the start of the file
4059		 */
4060		scanned = 1;
4061		index = 0;
 
 
 
 
 
 
 
 
4062		goto retry;
4063	}
4064
4065	if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
4066		mapping->writeback_index = done_index;
4067
4068	btrfs_add_delayed_iput(inode);
4069	return ret;
4070}
4071
4072static void flush_epd_write_bio(struct extent_page_data *epd)
 
 
 
 
 
 
 
4073{
4074	if (epd->bio) {
4075		int ret;
 
 
 
 
 
 
 
 
 
4076
4077		bio_set_op_attrs(epd->bio, REQ_OP_WRITE,
4078				 epd->sync_io ? REQ_SYNC : 0);
4079
4080		ret = submit_one_bio(epd->bio, 0, epd->bio_flags);
4081		BUG_ON(ret < 0); /* -ENOMEM */
4082		epd->bio = NULL;
4083	}
4084}
4085
4086static noinline void flush_write_bio(void *data)
4087{
4088	struct extent_page_data *epd = data;
4089	flush_epd_write_bio(epd);
4090}
4091
4092int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
4093			  get_extent_t *get_extent,
4094			  struct writeback_control *wbc)
4095{
4096	int ret;
4097	struct extent_page_data epd = {
4098		.bio = NULL,
4099		.tree = tree,
4100		.get_extent = get_extent,
4101		.extent_locked = 0,
4102		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4103		.bio_flags = 0,
4104	};
4105
4106	ret = __extent_writepage(page, wbc, &epd);
 
 
 
 
 
 
 
 
 
 
4107
4108	flush_epd_write_bio(&epd);
4109	return ret;
4110}
4111
4112int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
4113			      u64 start, u64 end, get_extent_t *get_extent,
4114			      int mode)
4115{
4116	int ret = 0;
4117	struct address_space *mapping = inode->i_mapping;
4118	struct page *page;
4119	unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4120		PAGE_SHIFT;
4121
4122	struct extent_page_data epd = {
4123		.bio = NULL,
4124		.tree = tree,
4125		.get_extent = get_extent,
4126		.extent_locked = 1,
4127		.sync_io = mode == WB_SYNC_ALL,
4128		.bio_flags = 0,
4129	};
4130	struct writeback_control wbc_writepages = {
4131		.sync_mode	= mode,
4132		.nr_to_write	= nr_pages * 2,
4133		.range_start	= start,
4134		.range_end	= end + 1,
4135	};
4136
4137	while (start <= end) {
4138		page = find_get_page(mapping, start >> PAGE_SHIFT);
4139		if (clear_page_dirty_for_io(page))
4140			ret = __extent_writepage(page, &wbc_writepages, &epd);
4141		else {
4142			if (tree->ops && tree->ops->writepage_end_io_hook)
4143				tree->ops->writepage_end_io_hook(page, start,
4144						 start + PAGE_SIZE - 1,
4145						 NULL, 1);
4146			unlock_page(page);
4147		}
4148		put_page(page);
4149		start += PAGE_SIZE;
4150	}
4151
4152	flush_epd_write_bio(&epd);
4153	return ret;
4154}
4155
4156int extent_writepages(struct extent_io_tree *tree,
4157		      struct address_space *mapping,
4158		      get_extent_t *get_extent,
4159		      struct writeback_control *wbc)
4160{
 
4161	int ret = 0;
4162	struct extent_page_data epd = {
4163		.bio = NULL,
4164		.tree = tree,
4165		.get_extent = get_extent,
4166		.extent_locked = 0,
4167		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4168		.bio_flags = 0,
4169	};
4170
4171	ret = extent_write_cache_pages(tree, mapping, wbc,
4172				       __extent_writepage, &epd,
4173				       flush_write_bio);
4174	flush_epd_write_bio(&epd);
 
 
 
 
4175	return ret;
4176}
4177
4178int extent_readpages(struct extent_io_tree *tree,
4179		     struct address_space *mapping,
4180		     struct list_head *pages, unsigned nr_pages,
4181		     get_extent_t get_extent)
4182{
4183	struct bio *bio = NULL;
4184	unsigned page_idx;
4185	unsigned long bio_flags = 0;
4186	struct page *pagepool[16];
4187	struct page *page;
4188	struct extent_map *em_cached = NULL;
4189	int nr = 0;
4190	u64 prev_em_start = (u64)-1;
4191
4192	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
4193		page = list_entry(pages->prev, struct page, lru);
4194
4195		prefetchw(&page->flags);
4196		list_del(&page->lru);
4197		if (add_to_page_cache_lru(page, mapping,
4198					page->index,
4199					readahead_gfp_mask(mapping))) {
4200			put_page(page);
4201			continue;
4202		}
4203
4204		pagepool[nr++] = page;
4205		if (nr < ARRAY_SIZE(pagepool))
4206			continue;
4207		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4208				   &bio, 0, &bio_flags, &prev_em_start);
4209		nr = 0;
4210	}
4211	if (nr)
4212		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4213				   &bio, 0, &bio_flags, &prev_em_start);
4214
4215	if (em_cached)
4216		free_extent_map(em_cached);
4217
4218	BUG_ON(!list_empty(pages));
4219	if (bio)
4220		return submit_one_bio(bio, 0, bio_flags);
4221	return 0;
4222}
4223
4224/*
4225 * basic invalidatepage code, this waits on any locked or writeback
4226 * ranges corresponding to the page, and then deletes any extent state
4227 * records from the tree
4228 */
4229int extent_invalidatepage(struct extent_io_tree *tree,
4230			  struct page *page, unsigned long offset)
4231{
4232	struct extent_state *cached_state = NULL;
4233	u64 start = page_offset(page);
4234	u64 end = start + PAGE_SIZE - 1;
4235	size_t blocksize = page->mapping->host->i_sb->s_blocksize;
 
 
 
4236
4237	start += ALIGN(offset, blocksize);
4238	if (start > end)
4239		return 0;
4240
4241	lock_extent_bits(tree, start, end, &cached_state);
4242	wait_on_page_writeback(page);
4243	clear_extent_bit(tree, start, end,
4244			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4245			 EXTENT_DO_ACCOUNTING,
4246			 1, 1, &cached_state, GFP_NOFS);
 
 
 
4247	return 0;
4248}
4249
4250/*
4251 * a helper for releasepage, this tests for areas of the page that
4252 * are locked or under IO and drops the related state bits if it is safe
4253 * to drop the page.
4254 */
4255static int try_release_extent_state(struct extent_map_tree *map,
4256				    struct extent_io_tree *tree,
4257				    struct page *page, gfp_t mask)
4258{
4259	u64 start = page_offset(page);
4260	u64 end = start + PAGE_SIZE - 1;
4261	int ret = 1;
 
 
 
 
 
 
 
 
4262
4263	if (test_range_bit(tree, start, end,
4264			   EXTENT_IOBITS, 0, NULL))
4265		ret = 0;
4266	else {
4267		if ((mask & GFP_NOFS) == GFP_NOFS)
4268			mask = GFP_NOFS;
4269		/*
4270		 * at this point we can safely clear everything except the
4271		 * locked bit and the nodatasum bit
 
 
4272		 */
4273		ret = clear_extent_bit(tree, start, end,
4274				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4275				 0, 0, NULL, mask);
4276
4277		/* if clear_extent_bit failed for enomem reasons,
4278		 * we can't allow the release to continue.
4279		 */
4280		if (ret < 0)
4281			ret = 0;
4282		else
4283			ret = 1;
4284	}
4285	return ret;
4286}
4287
4288/*
4289 * a helper for releasepage.  As long as there are no locked extents
4290 * in the range corresponding to the page, both state records and extent
4291 * map records are removed
4292 */
4293int try_release_extent_mapping(struct extent_map_tree *map,
4294			       struct extent_io_tree *tree, struct page *page,
4295			       gfp_t mask)
4296{
4297	struct extent_map *em;
4298	u64 start = page_offset(page);
4299	u64 end = start + PAGE_SIZE - 1;
 
 
4300
4301	if (gfpflags_allow_blocking(mask) &&
4302	    page->mapping->host->i_size > SZ_16M) {
4303		u64 len;
4304		while (start <= end) {
4305			len = end - start + 1;
4306			write_lock(&map->lock);
4307			em = lookup_extent_mapping(map, start, len);
4308			if (!em) {
4309				write_unlock(&map->lock);
4310				break;
4311			}
4312			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4313			    em->start != start) {
4314				write_unlock(&map->lock);
4315				free_extent_map(em);
4316				break;
4317			}
4318			if (!test_range_bit(tree, em->start,
4319					    extent_map_end(em) - 1,
4320					    EXTENT_LOCKED | EXTENT_WRITEBACK,
4321					    0, NULL)) {
4322				remove_extent_mapping(map, em);
4323				/* once for the rb tree */
4324				free_extent_map(em);
4325			}
4326			start = extent_map_end(em);
4327			write_unlock(&map->lock);
4328
4329			/* once for us */
4330			free_extent_map(em);
4331		}
4332	}
4333	return try_release_extent_state(map, tree, page, mask);
4334}
4335
4336/*
4337 * helper function for fiemap, which doesn't want to see any holes.
4338 * This maps until we find something past 'last'
4339 */
4340static struct extent_map *get_extent_skip_holes(struct inode *inode,
4341						u64 offset,
4342						u64 last,
4343						get_extent_t *get_extent)
4344{
4345	u64 sectorsize = btrfs_inode_sectorsize(inode);
4346	struct extent_map *em;
4347	u64 len;
4348
4349	if (offset >= last)
4350		return NULL;
4351
4352	while (1) {
4353		len = last - offset;
4354		if (len == 0)
 
4355			break;
4356		len = ALIGN(len, sectorsize);
4357		em = get_extent(inode, NULL, 0, offset, len, 0);
4358		if (IS_ERR_OR_NULL(em))
4359			return em;
4360
4361		/* if this isn't a hole return it */
4362		if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
4363		    em->block_start != EXTENT_MAP_HOLE) {
4364			return em;
4365		}
4366
4367		/* this is a hole, advance to the next extent */
4368		offset = extent_map_end(em);
4369		free_extent_map(em);
4370		if (offset >= last)
4371			break;
4372	}
4373	return NULL;
4374}
4375
4376int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4377		__u64 start, __u64 len, get_extent_t *get_extent)
4378{
4379	int ret = 0;
4380	u64 off = start;
4381	u64 max = start + len;
4382	u32 flags = 0;
4383	u32 found_type;
4384	u64 last;
4385	u64 last_for_get_extent = 0;
4386	u64 disko = 0;
4387	u64 isize = i_size_read(inode);
4388	struct btrfs_key found_key;
4389	struct extent_map *em = NULL;
4390	struct extent_state *cached_state = NULL;
4391	struct btrfs_path *path;
4392	struct btrfs_root *root = BTRFS_I(inode)->root;
4393	int end = 0;
4394	u64 em_start = 0;
4395	u64 em_len = 0;
4396	u64 em_end = 0;
4397
4398	if (len == 0)
4399		return -EINVAL;
4400
4401	path = btrfs_alloc_path();
4402	if (!path)
4403		return -ENOMEM;
4404	path->leave_spinning = 1;
4405
4406	start = round_down(start, btrfs_inode_sectorsize(inode));
4407	len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
4408
4409	/*
4410	 * lookup the last file extent.  We're not using i_size here
4411	 * because there might be preallocation past i_size
4412	 */
4413	ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
4414				       0);
4415	if (ret < 0) {
4416		btrfs_free_path(path);
4417		return ret;
4418	} else {
4419		WARN_ON(!ret);
4420		if (ret == 1)
4421			ret = 0;
4422	}
4423
4424	path->slots[0]--;
4425	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4426	found_type = found_key.type;
4427
4428	/* No extents, but there might be delalloc bits */
4429	if (found_key.objectid != btrfs_ino(inode) ||
4430	    found_type != BTRFS_EXTENT_DATA_KEY) {
4431		/* have to trust i_size as the end */
4432		last = (u64)-1;
4433		last_for_get_extent = isize;
4434	} else {
4435		/*
4436		 * remember the start of the last extent.  There are a
4437		 * bunch of different factors that go into the length of the
4438		 * extent, so its much less complex to remember where it started
4439		 */
4440		last = found_key.offset;
4441		last_for_get_extent = last + 1;
4442	}
4443	btrfs_release_path(path);
4444
4445	/*
4446	 * we might have some extents allocated but more delalloc past those
4447	 * extents.  so, we trust isize unless the start of the last extent is
4448	 * beyond isize
4449	 */
4450	if (last < isize) {
4451		last = (u64)-1;
4452		last_for_get_extent = isize;
4453	}
4454
4455	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4456			 &cached_state);
4457
4458	em = get_extent_skip_holes(inode, start, last_for_get_extent,
4459				   get_extent);
4460	if (!em)
4461		goto out;
4462	if (IS_ERR(em)) {
4463		ret = PTR_ERR(em);
4464		goto out;
4465	}
4466
4467	while (!end) {
4468		u64 offset_in_extent = 0;
4469
4470		/* break if the extent we found is outside the range */
4471		if (em->start >= max || extent_map_end(em) < off)
4472			break;
4473
 
 
 
4474		/*
4475		 * get_extent may return an extent that starts before our
4476		 * requested range.  We have to make sure the ranges
4477		 * we return to fiemap always move forward and don't
4478		 * overlap, so adjust the offsets here
4479		 */
4480		em_start = max(em->start, off);
4481
4482		/*
4483		 * record the offset from the start of the extent
4484		 * for adjusting the disk offset below.  Only do this if the
4485		 * extent isn't compressed since our in ram offset may be past
4486		 * what we have actually allocated on disk.
 
4487		 */
4488		if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4489			offset_in_extent = em_start - em->start;
4490		em_end = extent_map_end(em);
4491		em_len = em_end - em_start;
4492		disko = 0;
4493		flags = 0;
4494
4495		/*
4496		 * bump off for our next call to get_extent
 
 
 
 
 
4497		 */
4498		off = extent_map_end(em);
4499		if (off >= max)
4500			end = 1;
4501
4502		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4503			end = 1;
4504			flags |= FIEMAP_EXTENT_LAST;
4505		} else if (em->block_start == EXTENT_MAP_INLINE) {
4506			flags |= (FIEMAP_EXTENT_DATA_INLINE |
4507				  FIEMAP_EXTENT_NOT_ALIGNED);
4508		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
4509			flags |= (FIEMAP_EXTENT_DELALLOC |
4510				  FIEMAP_EXTENT_UNKNOWN);
4511		} else if (fieinfo->fi_extents_max) {
4512			struct btrfs_trans_handle *trans;
4513
4514			u64 bytenr = em->block_start -
4515				(em->start - em->orig_start);
4516
4517			disko = em->block_start + offset_in_extent;
4518
4519			/*
4520			 * We need a trans handle to get delayed refs
4521			 */
4522			trans = btrfs_join_transaction(root);
4523			/*
4524			 * It's OK if we can't start a trans we can still check
4525			 * from commit_root
4526			 */
4527			if (IS_ERR(trans))
4528				trans = NULL;
4529
 
4530			/*
4531			 * As btrfs supports shared space, this information
4532			 * can be exported to userspace tools via
4533			 * flag FIEMAP_EXTENT_SHARED.  If fi_extents_max == 0
4534			 * then we're just getting a count and we can skip the
4535			 * lookup stuff.
4536			 */
4537			ret = btrfs_check_shared(trans, root->fs_info,
4538						 root->objectid,
4539						 btrfs_ino(inode), bytenr);
4540			if (trans)
4541				btrfs_end_transaction(trans);
4542			if (ret < 0)
4543				goto out_free;
4544			if (ret)
4545				flags |= FIEMAP_EXTENT_SHARED;
4546			ret = 0;
4547		}
4548		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4549			flags |= FIEMAP_EXTENT_ENCODED;
4550		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4551			flags |= FIEMAP_EXTENT_UNWRITTEN;
4552
4553		free_extent_map(em);
4554		em = NULL;
4555		if ((em_start >= last) || em_len == (u64)-1 ||
4556		   (last == (u64)-1 && isize <= em_end)) {
4557			flags |= FIEMAP_EXTENT_LAST;
4558			end = 1;
4559		}
4560
4561		/* now scan forward to see if this is really the last extent. */
4562		em = get_extent_skip_holes(inode, off, last_for_get_extent,
4563					   get_extent);
4564		if (IS_ERR(em)) {
4565			ret = PTR_ERR(em);
4566			goto out;
4567		}
4568		if (!em) {
4569			flags |= FIEMAP_EXTENT_LAST;
4570			end = 1;
4571		}
4572		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
4573					      em_len, flags);
4574		if (ret) {
4575			if (ret == 1)
4576				ret = 0;
4577			goto out_free;
4578		}
4579	}
4580out_free:
4581	free_extent_map(em);
4582out:
4583	btrfs_free_path(path);
4584	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4585			     &cached_state, GFP_NOFS);
4586	return ret;
4587}
4588
4589static void __free_extent_buffer(struct extent_buffer *eb)
4590{
4591	btrfs_leak_debug_del(&eb->leak_list);
4592	kmem_cache_free(extent_buffer_cache, eb);
4593}
4594
4595int extent_buffer_under_io(struct extent_buffer *eb)
4596{
4597	return (atomic_read(&eb->io_pages) ||
4598		test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4599		test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4600}
4601
4602/*
4603 * Helper for releasing extent buffer page.
4604 */
4605static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4606{
4607	unsigned long index;
4608	struct page *page;
4609	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4610
4611	BUG_ON(extent_buffer_under_io(eb));
4612
4613	index = num_extent_pages(eb->start, eb->len);
4614	if (index == 0)
4615		return;
 
 
 
 
4616
4617	do {
4618		index--;
4619		page = eb->pages[index];
4620		if (!page)
4621			continue;
 
 
 
 
 
 
 
 
4622		if (mapped)
4623			spin_lock(&page->mapping->private_lock);
 
 
 
 
4624		/*
4625		 * We do this since we'll remove the pages after we've
4626		 * removed the eb from the radix tree, so we could race
4627		 * and have this page now attached to the new eb.  So
4628		 * only clear page_private if it's still connected to
4629		 * this eb.
4630		 */
4631		if (PagePrivate(page) &&
4632		    page->private == (unsigned long)eb) {
4633			BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4634			BUG_ON(PageDirty(page));
4635			BUG_ON(PageWriteback(page));
4636			/*
4637			 * We need to make sure we haven't be attached
4638			 * to a new eb.
4639			 */
4640			ClearPagePrivate(page);
4641			set_page_private(page, 0);
4642			/* One for the page private */
4643			put_page(page);
4644		}
4645
4646		if (mapped)
4647			spin_unlock(&page->mapping->private_lock);
 
 
 
 
 
 
 
 
 
 
 
 
4648
4649		/* One for when we allocated the page */
4650		put_page(page);
4651	} while (index != 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4652}
4653
4654/*
4655 * Helper for releasing the extent buffer.
4656 */
4657static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4658{
4659	btrfs_release_extent_buffer_page(eb);
 
4660	__free_extent_buffer(eb);
4661}
4662
4663static struct extent_buffer *
4664__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4665		      unsigned long len)
4666{
4667	struct extent_buffer *eb = NULL;
4668
4669	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4670	eb->start = start;
4671	eb->len = len;
4672	eb->fs_info = fs_info;
4673	eb->bflags = 0;
4674	rwlock_init(&eb->lock);
4675	atomic_set(&eb->write_locks, 0);
4676	atomic_set(&eb->read_locks, 0);
4677	atomic_set(&eb->blocking_readers, 0);
4678	atomic_set(&eb->blocking_writers, 0);
4679	atomic_set(&eb->spinning_readers, 0);
4680	atomic_set(&eb->spinning_writers, 0);
4681	eb->lock_nested = 0;
4682	init_waitqueue_head(&eb->write_lock_wq);
4683	init_waitqueue_head(&eb->read_lock_wq);
4684
4685	btrfs_leak_debug_add(&eb->leak_list, &buffers);
4686
4687	spin_lock_init(&eb->refs_lock);
4688	atomic_set(&eb->refs, 1);
4689	atomic_set(&eb->io_pages, 0);
4690
4691	/*
4692	 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4693	 */
4694	BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4695		> MAX_INLINE_EXTENT_BUFFER_SIZE);
4696	BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4697
4698	return eb;
4699}
4700
4701struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4702{
4703	unsigned long i;
4704	struct page *p;
4705	struct extent_buffer *new;
4706	unsigned long num_pages = num_extent_pages(src->start, src->len);
 
4707
4708	new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4709	if (new == NULL)
4710		return NULL;
4711
4712	for (i = 0; i < num_pages; i++) {
4713		p = alloc_page(GFP_NOFS);
4714		if (!p) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4715			btrfs_release_extent_buffer(new);
4716			return NULL;
4717		}
4718		attach_extent_buffer_page(new, p);
4719		WARN_ON(PageDirty(p));
4720		SetPageUptodate(p);
4721		new->pages[i] = p;
4722		copy_page(page_address(p), page_address(src->pages[i]));
4723	}
4724
4725	set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4726	set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
4727
4728	return new;
4729}
4730
4731struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4732						  u64 start, unsigned long len)
4733{
4734	struct extent_buffer *eb;
4735	unsigned long num_pages;
4736	unsigned long i;
4737
4738	num_pages = num_extent_pages(start, len);
4739
4740	eb = __alloc_extent_buffer(fs_info, start, len);
4741	if (!eb)
4742		return NULL;
4743
4744	for (i = 0; i < num_pages; i++) {
4745		eb->pages[i] = alloc_page(GFP_NOFS);
4746		if (!eb->pages[i])
 
 
 
 
 
4747			goto err;
4748	}
 
4749	set_extent_buffer_uptodate(eb);
4750	btrfs_set_header_nritems(eb, 0);
4751	set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4752
4753	return eb;
4754err:
4755	for (; i > 0; i--)
4756		__free_page(eb->pages[i - 1]);
 
 
 
 
4757	__free_extent_buffer(eb);
4758	return NULL;
4759}
4760
4761struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4762						u64 start)
4763{
4764	return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
4765}
4766
4767static void check_buffer_tree_ref(struct extent_buffer *eb)
4768{
4769	int refs;
4770	/* the ref bit is tricky.  We have to make sure it is set
4771	 * if we have the buffer dirty.   Otherwise the
4772	 * code to free a buffer can end up dropping a dirty
4773	 * page
4774	 *
4775	 * Once the ref bit is set, it won't go away while the
4776	 * buffer is dirty or in writeback, and it also won't
4777	 * go away while we have the reference count on the
4778	 * eb bumped.
4779	 *
4780	 * We can't just set the ref bit without bumping the
4781	 * ref on the eb because free_extent_buffer might
4782	 * see the ref bit and try to clear it.  If this happens
4783	 * free_extent_buffer might end up dropping our original
4784	 * ref by mistake and freeing the page before we are able
4785	 * to add one more ref.
4786	 *
4787	 * So bump the ref count first, then set the bit.  If someone
4788	 * beat us to it, drop the ref we added.
 
 
 
 
 
4789	 */
4790	refs = atomic_read(&eb->refs);
4791	if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4792		return;
4793
4794	spin_lock(&eb->refs_lock);
4795	if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4796		atomic_inc(&eb->refs);
4797	spin_unlock(&eb->refs_lock);
4798}
4799
4800static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4801		struct page *accessed)
4802{
4803	unsigned long num_pages, i;
4804
4805	check_buffer_tree_ref(eb);
4806
4807	num_pages = num_extent_pages(eb->start, eb->len);
4808	for (i = 0; i < num_pages; i++) {
4809		struct page *p = eb->pages[i];
4810
4811		if (p != accessed)
4812			mark_page_accessed(p);
4813	}
4814}
4815
4816struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4817					 u64 start)
4818{
4819	struct extent_buffer *eb;
4820
4821	rcu_read_lock();
4822	eb = radix_tree_lookup(&fs_info->buffer_radix,
4823			       start >> PAGE_SHIFT);
4824	if (eb && atomic_inc_not_zero(&eb->refs)) {
4825		rcu_read_unlock();
4826		/*
4827		 * Lock our eb's refs_lock to avoid races with
4828		 * free_extent_buffer. When we get our eb it might be flagged
4829		 * with EXTENT_BUFFER_STALE and another task running
4830		 * free_extent_buffer might have seen that flag set,
4831		 * eb->refs == 2, that the buffer isn't under IO (dirty and
4832		 * writeback flags not set) and it's still in the tree (flag
4833		 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4834		 * of decrementing the extent buffer's reference count twice.
4835		 * So here we could race and increment the eb's reference count,
4836		 * clear its stale flag, mark it as dirty and drop our reference
4837		 * before the other task finishes executing free_extent_buffer,
4838		 * which would later result in an attempt to free an extent
4839		 * buffer that is dirty.
4840		 */
4841		if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4842			spin_lock(&eb->refs_lock);
4843			spin_unlock(&eb->refs_lock);
4844		}
4845		mark_extent_buffer_accessed(eb, NULL);
4846		return eb;
4847	}
4848	rcu_read_unlock();
4849
4850	return NULL;
4851}
4852
4853#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4854struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4855					u64 start)
4856{
4857	struct extent_buffer *eb, *exists = NULL;
4858	int ret;
4859
4860	eb = find_extent_buffer(fs_info, start);
4861	if (eb)
4862		return eb;
4863	eb = alloc_dummy_extent_buffer(fs_info, start);
4864	if (!eb)
4865		return NULL;
4866	eb->fs_info = fs_info;
4867again:
4868	ret = radix_tree_preload(GFP_NOFS);
4869	if (ret)
 
4870		goto free_eb;
 
4871	spin_lock(&fs_info->buffer_lock);
4872	ret = radix_tree_insert(&fs_info->buffer_radix,
4873				start >> PAGE_SHIFT, eb);
4874	spin_unlock(&fs_info->buffer_lock);
4875	radix_tree_preload_end();
4876	if (ret == -EEXIST) {
4877		exists = find_extent_buffer(fs_info, start);
4878		if (exists)
4879			goto free_eb;
4880		else
4881			goto again;
4882	}
4883	check_buffer_tree_ref(eb);
4884	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4885
4886	/*
4887	 * We will free dummy extent buffer's if they come into
4888	 * free_extent_buffer with a ref count of 2, but if we are using this we
4889	 * want the buffers to stay in memory until we're done with them, so
4890	 * bump the ref count again.
4891	 */
4892	atomic_inc(&eb->refs);
4893	return eb;
4894free_eb:
4895	btrfs_release_extent_buffer(eb);
4896	return exists;
4897}
4898#endif
4899
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4900struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4901					  u64 start)
4902{
4903	unsigned long len = fs_info->nodesize;
4904	unsigned long num_pages = num_extent_pages(start, len);
4905	unsigned long i;
4906	unsigned long index = start >> PAGE_SHIFT;
4907	struct extent_buffer *eb;
4908	struct extent_buffer *exists = NULL;
4909	struct page *p;
4910	struct address_space *mapping = fs_info->btree_inode->i_mapping;
 
4911	int uptodate = 1;
4912	int ret;
4913
4914	if (!IS_ALIGNED(start, fs_info->sectorsize)) {
4915		btrfs_err(fs_info, "bad tree block start %llu", start);
4916		return ERR_PTR(-EINVAL);
 
 
 
 
 
 
 
4917	}
 
 
 
4918
4919	eb = find_extent_buffer(fs_info, start);
4920	if (eb)
4921		return eb;
4922
4923	eb = __alloc_extent_buffer(fs_info, start, len);
4924	if (!eb)
4925		return ERR_PTR(-ENOMEM);
4926
4927	for (i = 0; i < num_pages; i++, index++) {
4928		p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4929		if (!p) {
4930			exists = ERR_PTR(-ENOMEM);
4931			goto free_eb;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4932		}
 
4933
4934		spin_lock(&mapping->private_lock);
4935		if (PagePrivate(p)) {
4936			/*
4937			 * We could have already allocated an eb for this page
4938			 * and attached one so lets see if we can get a ref on
4939			 * the existing eb, and if we can we know it's good and
4940			 * we can just return that one, else we know we can just
4941			 * overwrite page->private.
4942			 */
4943			exists = (struct extent_buffer *)p->private;
4944			if (atomic_inc_not_zero(&exists->refs)) {
4945				spin_unlock(&mapping->private_lock);
4946				unlock_page(p);
4947				put_page(p);
4948				mark_extent_buffer_accessed(exists, p);
4949				goto free_eb;
4950			}
4951			exists = NULL;
4952
4953			/*
4954			 * Do this so attach doesn't complain and we need to
4955			 * drop the ref the old guy had.
4956			 */
4957			ClearPagePrivate(p);
4958			WARN_ON(PageDirty(p));
4959			put_page(p);
4960		}
4961		attach_extent_buffer_page(eb, p);
4962		spin_unlock(&mapping->private_lock);
4963		WARN_ON(PageDirty(p));
4964		eb->pages[i] = p;
4965		if (!PageUptodate(p))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4966			uptodate = 0;
4967
4968		/*
4969		 * see below about how we avoid a nasty race with release page
4970		 * and why we unlock later
 
 
 
4971		 */
4972	}
4973	if (uptodate)
4974		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
 
 
 
4975again:
4976	ret = radix_tree_preload(GFP_NOFS);
4977	if (ret) {
4978		exists = ERR_PTR(ret);
4979		goto free_eb;
4980	}
4981
4982	spin_lock(&fs_info->buffer_lock);
4983	ret = radix_tree_insert(&fs_info->buffer_radix,
4984				start >> PAGE_SHIFT, eb);
4985	spin_unlock(&fs_info->buffer_lock);
4986	radix_tree_preload_end();
4987	if (ret == -EEXIST) {
4988		exists = find_extent_buffer(fs_info, start);
4989		if (exists)
4990			goto free_eb;
 
4991		else
4992			goto again;
4993	}
4994	/* add one reference for the tree */
4995	check_buffer_tree_ref(eb);
4996	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4997
4998	/*
4999	 * there is a race where release page may have
5000	 * tried to find this extent buffer in the radix
5001	 * but failed.  It will tell the VM it is safe to
5002	 * reclaim the, and it will clear the page private bit.
5003	 * We must make sure to set the page private bit properly
5004	 * after the extent buffer is in the radix tree so
5005	 * it doesn't get lost
5006	 */
5007	SetPageChecked(eb->pages[0]);
5008	for (i = 1; i < num_pages; i++) {
5009		p = eb->pages[i];
5010		ClearPageChecked(p);
5011		unlock_page(p);
5012	}
5013	unlock_page(eb->pages[0]);
5014	return eb;
5015
5016free_eb:
5017	WARN_ON(!atomic_dec_and_test(&eb->refs));
5018	for (i = 0; i < num_pages; i++) {
5019		if (eb->pages[i])
5020			unlock_page(eb->pages[i]);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5021	}
 
 
 
 
 
5022
5023	btrfs_release_extent_buffer(eb);
5024	return exists;
 
 
 
5025}
5026
5027static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5028{
5029	struct extent_buffer *eb =
5030			container_of(head, struct extent_buffer, rcu_head);
5031
5032	__free_extent_buffer(eb);
5033}
5034
5035/* Expects to have eb->eb_lock already held */
5036static int release_extent_buffer(struct extent_buffer *eb)
 
5037{
 
 
5038	WARN_ON(atomic_read(&eb->refs) == 0);
5039	if (atomic_dec_and_test(&eb->refs)) {
5040		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5041			struct btrfs_fs_info *fs_info = eb->fs_info;
5042
5043			spin_unlock(&eb->refs_lock);
5044
5045			spin_lock(&fs_info->buffer_lock);
5046			radix_tree_delete(&fs_info->buffer_radix,
5047					  eb->start >> PAGE_SHIFT);
5048			spin_unlock(&fs_info->buffer_lock);
5049		} else {
5050			spin_unlock(&eb->refs_lock);
5051		}
5052
 
5053		/* Should be safe to release our pages at this point */
5054		btrfs_release_extent_buffer_page(eb);
5055#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5056		if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
5057			__free_extent_buffer(eb);
5058			return 1;
5059		}
5060#endif
5061		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5062		return 1;
5063	}
5064	spin_unlock(&eb->refs_lock);
5065
5066	return 0;
5067}
5068
5069void free_extent_buffer(struct extent_buffer *eb)
5070{
5071	int refs;
5072	int old;
5073	if (!eb)
5074		return;
5075
 
5076	while (1) {
5077		refs = atomic_read(&eb->refs);
5078		if (refs <= 3)
 
5079			break;
5080		old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5081		if (old == refs)
5082			return;
5083	}
5084
5085	spin_lock(&eb->refs_lock);
5086	if (atomic_read(&eb->refs) == 2 &&
5087	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
5088		atomic_dec(&eb->refs);
5089
5090	if (atomic_read(&eb->refs) == 2 &&
5091	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5092	    !extent_buffer_under_io(eb) &&
5093	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5094		atomic_dec(&eb->refs);
5095
5096	/*
5097	 * I know this is terrible, but it's temporary until we stop tracking
5098	 * the uptodate bits and such for the extent buffers.
5099	 */
5100	release_extent_buffer(eb);
5101}
5102
5103void free_extent_buffer_stale(struct extent_buffer *eb)
5104{
5105	if (!eb)
5106		return;
5107
5108	spin_lock(&eb->refs_lock);
5109	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5110
5111	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5112	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5113		atomic_dec(&eb->refs);
5114	release_extent_buffer(eb);
5115}
5116
5117void clear_extent_buffer_dirty(struct extent_buffer *eb)
5118{
5119	unsigned long i;
5120	unsigned long num_pages;
5121	struct page *page;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5122
5123	num_pages = num_extent_pages(eb->start, eb->len);
5124
5125	for (i = 0; i < num_pages; i++) {
5126		page = eb->pages[i];
5127		if (!PageDirty(page))
5128			continue;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5129
5130		lock_page(page);
5131		WARN_ON(!PagePrivate(page));
 
5132
5133		clear_page_dirty_for_io(page);
5134		spin_lock_irq(&page->mapping->tree_lock);
5135		if (!PageDirty(page)) {
5136			radix_tree_tag_clear(&page->mapping->page_tree,
5137						page_index(page),
5138						PAGECACHE_TAG_DIRTY);
5139		}
5140		spin_unlock_irq(&page->mapping->tree_lock);
5141		ClearPageError(page);
5142		unlock_page(page);
5143	}
5144	WARN_ON(atomic_read(&eb->refs) == 0);
5145}
5146
5147int set_extent_buffer_dirty(struct extent_buffer *eb)
5148{
5149	unsigned long i;
5150	unsigned long num_pages;
5151	int was_dirty = 0;
5152
5153	check_buffer_tree_ref(eb);
5154
5155	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5156
5157	num_pages = num_extent_pages(eb->start, eb->len);
5158	WARN_ON(atomic_read(&eb->refs) == 0);
5159	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
 
5160
5161	for (i = 0; i < num_pages; i++)
5162		set_page_dirty(eb->pages[i]);
5163	return was_dirty;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5164}
5165
5166void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5167{
5168	unsigned long i;
5169	struct page *page;
5170	unsigned long num_pages;
5171
5172	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5173	num_pages = num_extent_pages(eb->start, eb->len);
5174	for (i = 0; i < num_pages; i++) {
5175		page = eb->pages[i];
5176		if (page)
5177			ClearPageUptodate(page);
 
 
 
 
 
 
 
 
 
 
5178	}
5179}
5180
5181void set_extent_buffer_uptodate(struct extent_buffer *eb)
5182{
5183	unsigned long i;
5184	struct page *page;
5185	unsigned long num_pages;
5186
5187	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5188	num_pages = num_extent_pages(eb->start, eb->len);
5189	for (i = 0; i < num_pages; i++) {
5190		page = eb->pages[i];
5191		SetPageUptodate(page);
 
 
 
 
 
 
 
 
5192	}
5193}
5194
5195int extent_buffer_uptodate(struct extent_buffer *eb)
5196{
5197	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
 
 
5198}
5199
5200int read_extent_buffer_pages(struct extent_io_tree *tree,
5201			     struct extent_buffer *eb, int wait,
5202			     get_extent_t *get_extent, int mirror_num)
5203{
5204	unsigned long i;
5205	struct page *page;
5206	int err;
5207	int ret = 0;
5208	int locked_pages = 0;
5209	int all_uptodate = 1;
5210	unsigned long num_pages;
5211	unsigned long num_reads = 0;
5212	struct bio *bio = NULL;
5213	unsigned long bio_flags = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5214
5215	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5216		return 0;
5217
5218	num_pages = num_extent_pages(eb->start, eb->len);
5219	for (i = 0; i < num_pages; i++) {
5220		page = eb->pages[i];
5221		if (wait == WAIT_NONE) {
5222			if (!trylock_page(page))
5223				goto unlock_exit;
5224		} else {
5225			lock_page(page);
5226		}
5227		locked_pages++;
5228	}
5229	/*
5230	 * We need to firstly lock all pages to make sure that
5231	 * the uptodate bit of our pages won't be affected by
5232	 * clear_extent_buffer_uptodate().
5233	 */
5234	for (i = 0; i < num_pages; i++) {
5235		page = eb->pages[i];
5236		if (!PageUptodate(page)) {
5237			num_reads++;
5238			all_uptodate = 0;
5239		}
5240	}
5241
5242	if (all_uptodate) {
5243		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5244		goto unlock_exit;
 
 
 
 
 
 
 
 
 
 
5245	}
5246
5247	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5248	eb->read_mirror = 0;
5249	atomic_set(&eb->io_pages, num_reads);
5250	for (i = 0; i < num_pages; i++) {
5251		page = eb->pages[i];
5252
5253		if (!PageUptodate(page)) {
5254			if (ret) {
5255				atomic_dec(&eb->io_pages);
5256				unlock_page(page);
5257				continue;
5258			}
5259
5260			ClearPageError(page);
5261			err = __extent_read_full_page(tree, page,
5262						      get_extent, &bio,
5263						      mirror_num, &bio_flags,
5264						      REQ_META);
5265			if (err) {
5266				ret = err;
5267				/*
5268				 * We use &bio in above __extent_read_full_page,
5269				 * so we ensure that if it returns error, the
5270				 * current page fails to add itself to bio and
5271				 * it's been unlocked.
5272				 *
5273				 * We must dec io_pages by ourselves.
5274				 */
5275				atomic_dec(&eb->io_pages);
5276			}
5277		} else {
5278			unlock_page(page);
5279		}
5280	}
 
5281
5282	if (bio) {
5283		err = submit_one_bio(bio, mirror_num, bio_flags);
5284		if (err)
5285			return err;
 
5286	}
5287
5288	if (ret || wait != WAIT_COMPLETE)
5289		return ret;
5290
5291	for (i = 0; i < num_pages; i++) {
5292		page = eb->pages[i];
5293		wait_on_page_locked(page);
5294		if (!PageUptodate(page))
5295			ret = -EIO;
5296	}
 
5297
5298	return ret;
 
5299
5300unlock_exit:
5301	while (locked_pages > 0) {
5302		locked_pages--;
5303		page = eb->pages[locked_pages];
5304		unlock_page(page);
5305	}
5306	return ret;
 
 
 
 
 
 
 
 
 
 
5307}
5308
5309void read_extent_buffer(struct extent_buffer *eb, void *dstv,
5310			unsigned long start,
5311			unsigned long len)
5312{
 
5313	size_t cur;
5314	size_t offset;
5315	struct page *page;
5316	char *kaddr;
5317	char *dst = (char *)dstv;
5318	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5319	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5320
5321	WARN_ON(start > eb->len);
5322	WARN_ON(start + len > eb->start + eb->len);
 
 
 
 
 
 
 
 
 
 
 
5323
5324	offset = (start_offset + start) & (PAGE_SIZE - 1);
5325
5326	while (len > 0) {
5327		page = eb->pages[i];
5328
5329		cur = min(len, (PAGE_SIZE - offset));
5330		kaddr = page_address(page);
5331		memcpy(dst, kaddr + offset, cur);
5332
5333		dst += cur;
5334		len -= cur;
5335		offset = 0;
5336		i++;
5337	}
5338}
5339
5340int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
5341			unsigned long start,
5342			unsigned long len)
5343{
 
5344	size_t cur;
5345	size_t offset;
5346	struct page *page;
5347	char *kaddr;
5348	char __user *dst = (char __user *)dstv;
5349	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5350	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5351	int ret = 0;
5352
5353	WARN_ON(start > eb->len);
5354	WARN_ON(start + len > eb->start + eb->len);
5355
5356	offset = (start_offset + start) & (PAGE_SIZE - 1);
 
 
 
 
 
 
5357
5358	while (len > 0) {
5359		page = eb->pages[i];
5360
5361		cur = min(len, (PAGE_SIZE - offset));
5362		kaddr = page_address(page);
5363		if (copy_to_user(dst, kaddr + offset, cur)) {
5364			ret = -EFAULT;
5365			break;
5366		}
5367
5368		dst += cur;
5369		len -= cur;
5370		offset = 0;
5371		i++;
5372	}
5373
5374	return ret;
5375}
5376
5377/*
5378 * return 0 if the item is found within a page.
5379 * return 1 if the item spans two pages.
5380 * return -EINVAL otherwise.
5381 */
5382int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5383			       unsigned long min_len, char **map,
5384			       unsigned long *map_start,
5385			       unsigned long *map_len)
5386{
5387	size_t offset = start & (PAGE_SIZE - 1);
5388	char *kaddr;
5389	struct page *p;
5390	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5391	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5392	unsigned long end_i = (start_offset + start + min_len - 1) >>
5393		PAGE_SHIFT;
5394
5395	if (i != end_i)
5396		return 1;
5397
5398	if (i == 0) {
5399		offset = start_offset;
5400		*map_start = 0;
5401	} else {
5402		offset = 0;
5403		*map_start = ((u64)i << PAGE_SHIFT) - start_offset;
5404	}
5405
5406	if (start + min_len > eb->len) {
5407		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5408		       eb->start, eb->len, start, min_len);
5409		return -EINVAL;
5410	}
5411
5412	p = eb->pages[i];
5413	kaddr = page_address(p);
5414	*map = kaddr + offset;
5415	*map_len = PAGE_SIZE - offset;
5416	return 0;
5417}
5418
5419int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
5420			  unsigned long start,
5421			  unsigned long len)
5422{
 
5423	size_t cur;
5424	size_t offset;
5425	struct page *page;
5426	char *kaddr;
5427	char *ptr = (char *)ptrv;
5428	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5429	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5430	int ret = 0;
5431
5432	WARN_ON(start > eb->len);
5433	WARN_ON(start + len > eb->start + eb->len);
5434
5435	offset = (start_offset + start) & (PAGE_SIZE - 1);
5436
5437	while (len > 0) {
5438		page = eb->pages[i];
5439
5440		cur = min(len, (PAGE_SIZE - offset));
5441
5442		kaddr = page_address(page);
 
 
5443		ret = memcmp(ptr, kaddr + offset, cur);
5444		if (ret)
5445			break;
5446
5447		ptr += cur;
5448		len -= cur;
5449		offset = 0;
5450		i++;
5451	}
5452	return ret;
5453}
5454
5455void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
5456		const void *srcv)
 
 
 
 
 
5457{
5458	char *kaddr;
 
5459
5460	WARN_ON(!PageUptodate(eb->pages[0]));
5461	kaddr = page_address(eb->pages[0]);
5462	memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
5463			BTRFS_FSID_SIZE);
5464}
5465
5466void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
5467{
5468	char *kaddr;
 
 
 
 
 
 
 
5469
5470	WARN_ON(!PageUptodate(eb->pages[0]));
5471	kaddr = page_address(eb->pages[0]);
5472	memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
5473			BTRFS_FSID_SIZE);
 
 
 
 
 
5474}
5475
5476void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5477			 unsigned long start, unsigned long len)
 
5478{
 
5479	size_t cur;
5480	size_t offset;
5481	struct page *page;
5482	char *kaddr;
5483	char *src = (char *)srcv;
5484	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5485	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
 
5486
5487	WARN_ON(start > eb->len);
5488	WARN_ON(start + len > eb->start + eb->len);
5489
5490	offset = (start_offset + start) & (PAGE_SIZE - 1);
 
 
 
 
 
 
 
 
5491
5492	while (len > 0) {
5493		page = eb->pages[i];
5494		WARN_ON(!PageUptodate(page));
5495
5496		cur = min(len, PAGE_SIZE - offset);
5497		kaddr = page_address(page);
5498		memcpy(kaddr + offset, src, cur);
 
 
 
5499
5500		src += cur;
5501		len -= cur;
5502		offset = 0;
5503		i++;
5504	}
5505}
5506
5507void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
5508		unsigned long len)
5509{
5510	size_t cur;
5511	size_t offset;
5512	struct page *page;
5513	char *kaddr;
5514	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5515	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5516
5517	WARN_ON(start > eb->len);
5518	WARN_ON(start + len > eb->start + eb->len);
 
 
 
5519
5520	offset = (start_offset + start) & (PAGE_SIZE - 1);
 
 
 
5521
5522	while (len > 0) {
5523		page = eb->pages[i];
5524		WARN_ON(!PageUptodate(page));
 
5525
5526		cur = min(len, PAGE_SIZE - offset);
5527		kaddr = page_address(page);
5528		memset(kaddr + offset, 0, cur);
5529
5530		len -= cur;
5531		offset = 0;
5532		i++;
5533	}
5534}
5535
5536void copy_extent_buffer_full(struct extent_buffer *dst,
5537			     struct extent_buffer *src)
5538{
5539	int i;
5540	unsigned num_pages;
 
 
 
 
 
 
 
 
5541
5542	ASSERT(dst->len == src->len);
5543
5544	num_pages = num_extent_pages(dst->start, dst->len);
5545	for (i = 0; i < num_pages; i++)
5546		copy_page(page_address(dst->pages[i]),
5547				page_address(src->pages[i]));
 
 
 
 
 
 
5548}
5549
5550void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
 
5551			unsigned long dst_offset, unsigned long src_offset,
5552			unsigned long len)
5553{
 
5554	u64 dst_len = dst->len;
5555	size_t cur;
5556	size_t offset;
5557	struct page *page;
5558	char *kaddr;
5559	size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5560	unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
 
 
 
5561
5562	WARN_ON(src->len != dst_len);
5563
5564	offset = (start_offset + dst_offset) &
5565		(PAGE_SIZE - 1);
5566
5567	while (len > 0) {
5568		page = dst->pages[i];
5569		WARN_ON(!PageUptodate(page));
5570
5571		cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5572
5573		kaddr = page_address(page);
5574		read_extent_buffer(src, kaddr + offset, src_offset, cur);
5575
5576		src_offset += cur;
5577		len -= cur;
5578		offset = 0;
5579		i++;
5580	}
5581}
5582
5583void le_bitmap_set(u8 *map, unsigned int start, int len)
5584{
5585	u8 *p = map + BIT_BYTE(start);
5586	const unsigned int size = start + len;
5587	int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5588	u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
5589
5590	while (len - bits_to_set >= 0) {
5591		*p |= mask_to_set;
5592		len -= bits_to_set;
5593		bits_to_set = BITS_PER_BYTE;
5594		mask_to_set = ~0;
5595		p++;
5596	}
5597	if (len) {
5598		mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5599		*p |= mask_to_set;
5600	}
5601}
5602
5603void le_bitmap_clear(u8 *map, unsigned int start, int len)
5604{
5605	u8 *p = map + BIT_BYTE(start);
5606	const unsigned int size = start + len;
5607	int bits_to_clear = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5608	u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(start);
5609
5610	while (len - bits_to_clear >= 0) {
5611		*p &= ~mask_to_clear;
5612		len -= bits_to_clear;
5613		bits_to_clear = BITS_PER_BYTE;
5614		mask_to_clear = ~0;
5615		p++;
5616	}
5617	if (len) {
5618		mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5619		*p &= ~mask_to_clear;
5620	}
5621}
5622
5623/*
5624 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5625 * given bit number
5626 * @eb: the extent buffer
5627 * @start: offset of the bitmap item in the extent buffer
5628 * @nr: bit number
5629 * @page_index: return index of the page in the extent buffer that contains the
5630 * given bit number
5631 * @page_offset: return offset into the page given by page_index
5632 *
5633 * This helper hides the ugliness of finding the byte in an extent buffer which
5634 * contains a given bit.
5635 */
5636static inline void eb_bitmap_offset(struct extent_buffer *eb,
5637				    unsigned long start, unsigned long nr,
5638				    unsigned long *page_index,
5639				    size_t *page_offset)
5640{
5641	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5642	size_t byte_offset = BIT_BYTE(nr);
5643	size_t offset;
5644
5645	/*
5646	 * The byte we want is the offset of the extent buffer + the offset of
5647	 * the bitmap item in the extent buffer + the offset of the byte in the
5648	 * bitmap item.
5649	 */
5650	offset = start_offset + start + byte_offset;
5651
5652	*page_index = offset >> PAGE_SHIFT;
5653	*page_offset = offset & (PAGE_SIZE - 1);
5654}
5655
5656/**
5657 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5658 * @eb: the extent buffer
5659 * @start: offset of the bitmap item in the extent buffer
5660 * @nr: bit number to test
 
5661 */
5662int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
5663			   unsigned long nr)
5664{
5665	u8 *kaddr;
5666	struct page *page;
5667	unsigned long i;
5668	size_t offset;
 
5669
5670	eb_bitmap_offset(eb, start, nr, &i, &offset);
5671	page = eb->pages[i];
5672	WARN_ON(!PageUptodate(page));
5673	kaddr = page_address(page);
5674	return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5675}
5676
5677/**
5678 * extent_buffer_bitmap_set - set an area of a bitmap
5679 * @eb: the extent buffer
5680 * @start: offset of the bitmap item in the extent buffer
5681 * @pos: bit number of the first bit
5682 * @len: number of bits to set
 
 
 
 
 
 
 
 
 
 
5683 */
5684void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
5685			      unsigned long pos, unsigned long len)
5686{
 
 
 
 
5687	u8 *kaddr;
5688	struct page *page;
5689	unsigned long i;
5690	size_t offset;
5691	const unsigned int size = pos + len;
5692	int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5693	u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5694
5695	eb_bitmap_offset(eb, start, pos, &i, &offset);
5696	page = eb->pages[i];
5697	WARN_ON(!PageUptodate(page));
5698	kaddr = page_address(page);
5699
5700	while (len >= bits_to_set) {
5701		kaddr[offset] |= mask_to_set;
5702		len -= bits_to_set;
5703		bits_to_set = BITS_PER_BYTE;
5704		mask_to_set = ~0;
5705		if (++offset >= PAGE_SIZE && len > 0) {
5706			offset = 0;
5707			page = eb->pages[++i];
5708			WARN_ON(!PageUptodate(page));
5709			kaddr = page_address(page);
5710		}
5711	}
5712	if (len) {
5713		mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5714		kaddr[offset] |= mask_to_set;
5715	}
5716}
5717
5718
5719/**
5720 * extent_buffer_bitmap_clear - clear an area of a bitmap
5721 * @eb: the extent buffer
5722 * @start: offset of the bitmap item in the extent buffer
5723 * @pos: bit number of the first bit
5724 * @len: number of bits to clear
5725 */
5726void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
5727				unsigned long pos, unsigned long len)
5728{
 
 
 
 
 
 
5729	u8 *kaddr;
5730	struct page *page;
5731	unsigned long i;
5732	size_t offset;
5733	const unsigned int size = pos + len;
5734	int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5735	u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5736
5737	eb_bitmap_offset(eb, start, pos, &i, &offset);
5738	page = eb->pages[i];
5739	WARN_ON(!PageUptodate(page));
5740	kaddr = page_address(page);
5741
5742	while (len >= bits_to_clear) {
5743		kaddr[offset] &= ~mask_to_clear;
5744		len -= bits_to_clear;
5745		bits_to_clear = BITS_PER_BYTE;
5746		mask_to_clear = ~0;
5747		if (++offset >= PAGE_SIZE && len > 0) {
5748			offset = 0;
5749			page = eb->pages[++i];
5750			WARN_ON(!PageUptodate(page));
5751			kaddr = page_address(page);
5752		}
5753	}
5754	if (len) {
5755		mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5756		kaddr[offset] &= ~mask_to_clear;
5757	}
5758}
5759
5760static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5761{
5762	unsigned long distance = (src > dst) ? src - dst : dst - src;
5763	return distance < len;
5764}
5765
5766static void copy_pages(struct page *dst_page, struct page *src_page,
5767		       unsigned long dst_off, unsigned long src_off,
5768		       unsigned long len)
5769{
5770	char *dst_kaddr = page_address(dst_page);
5771	char *src_kaddr;
5772	int must_memmove = 0;
5773
5774	if (dst_page != src_page) {
5775		src_kaddr = page_address(src_page);
5776	} else {
5777		src_kaddr = dst_kaddr;
5778		if (areas_overlap(src_off, dst_off, len))
5779			must_memmove = 1;
5780	}
5781
5782	if (must_memmove)
5783		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5784	else
5785		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5786}
5787
5788void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5789			   unsigned long src_offset, unsigned long len)
5790{
5791	struct btrfs_fs_info *fs_info = dst->fs_info;
5792	size_t cur;
5793	size_t dst_off_in_page;
5794	size_t src_off_in_page;
5795	size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5796	unsigned long dst_i;
5797	unsigned long src_i;
5798
5799	if (src_offset + len > dst->len) {
5800		btrfs_err(fs_info,
5801			"memmove bogus src_offset %lu move len %lu dst len %lu",
5802			 src_offset, len, dst->len);
5803		BUG_ON(1);
5804	}
5805	if (dst_offset + len > dst->len) {
5806		btrfs_err(fs_info,
5807			"memmove bogus dst_offset %lu move len %lu dst len %lu",
5808			 dst_offset, len, dst->len);
5809		BUG_ON(1);
5810	}
5811
5812	while (len > 0) {
5813		dst_off_in_page = (start_offset + dst_offset) &
5814			(PAGE_SIZE - 1);
5815		src_off_in_page = (start_offset + src_offset) &
5816			(PAGE_SIZE - 1);
5817
5818		dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
5819		src_i = (start_offset + src_offset) >> PAGE_SHIFT;
5820
5821		cur = min(len, (unsigned long)(PAGE_SIZE -
5822					       src_off_in_page));
5823		cur = min_t(unsigned long, cur,
5824			(unsigned long)(PAGE_SIZE - dst_off_in_page));
5825
5826		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5827			   dst_off_in_page, src_off_in_page, cur);
 
 
 
 
5828
5829		src_offset += cur;
5830		dst_offset += cur;
5831		len -= cur;
 
 
 
 
 
 
 
 
 
 
5832	}
5833}
5834
5835void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5836			   unsigned long src_offset, unsigned long len)
 
5837{
5838	struct btrfs_fs_info *fs_info = dst->fs_info;
5839	size_t cur;
5840	size_t dst_off_in_page;
5841	size_t src_off_in_page;
5842	unsigned long dst_end = dst_offset + len - 1;
5843	unsigned long src_end = src_offset + len - 1;
5844	size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5845	unsigned long dst_i;
5846	unsigned long src_i;
5847
5848	if (src_offset + len > dst->len) {
5849		btrfs_err(fs_info,
5850			  "memmove bogus src_offset %lu move len %lu len %lu",
5851			  src_offset, len, dst->len);
5852		BUG_ON(1);
5853	}
5854	if (dst_offset + len > dst->len) {
5855		btrfs_err(fs_info,
5856			  "memmove bogus dst_offset %lu move len %lu len %lu",
5857			  dst_offset, len, dst->len);
5858		BUG_ON(1);
5859	}
5860	if (dst_offset < src_offset) {
5861		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5862		return;
5863	}
 
 
 
 
 
 
5864	while (len > 0) {
5865		dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
5866		src_i = (start_offset + src_end) >> PAGE_SHIFT;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5867
5868		dst_off_in_page = (start_offset + dst_end) &
5869			(PAGE_SIZE - 1);
5870		src_off_in_page = (start_offset + src_end) &
5871			(PAGE_SIZE - 1);
5872
5873		cur = min_t(unsigned long, len, src_off_in_page + 1);
5874		cur = min(cur, dst_off_in_page + 1);
5875		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5876			   dst_off_in_page - cur + 1,
5877			   src_off_in_page - cur + 1, cur);
5878
5879		dst_end -= cur;
5880		src_end -= cur;
5881		len -= cur;
5882	}
5883}
5884
5885int try_release_extent_buffer(struct page *page)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5886{
5887	struct extent_buffer *eb;
5888
 
 
 
5889	/*
5890	 * We need to make sure nobody is attaching this page to an eb right
5891	 * now.
5892	 */
5893	spin_lock(&page->mapping->private_lock);
5894	if (!PagePrivate(page)) {
5895		spin_unlock(&page->mapping->private_lock);
5896		return 1;
5897	}
5898
5899	eb = (struct extent_buffer *)page->private;
5900	BUG_ON(!eb);
5901
5902	/*
5903	 * This is a little awful but should be ok, we need to make sure that
5904	 * the eb doesn't disappear out from under us while we're looking at
5905	 * this page.
5906	 */
5907	spin_lock(&eb->refs_lock);
5908	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5909		spin_unlock(&eb->refs_lock);
5910		spin_unlock(&page->mapping->private_lock);
5911		return 0;
5912	}
5913	spin_unlock(&page->mapping->private_lock);
5914
5915	/*
5916	 * If tree ref isn't set then we know the ref on this eb is a real ref,
5917	 * so just return, this page will likely be freed soon anyway.
5918	 */
5919	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5920		spin_unlock(&eb->refs_lock);
5921		return 0;
5922	}
5923
5924	return release_extent_buffer(eb);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5925}