1// SPDX-License-Identifier: GPL-2.0
   2
   3#include <linux/bitops.h>
   4#include <linux/slab.h>
   5#include <linux/bio.h>
   6#include <linux/mm.h>
   7#include <linux/pagemap.h>
   8#include <linux/page-flags.h>
   9#include <linux/spinlock.h>
  10#include <linux/blkdev.h>
  11#include <linux/swap.h>
  12#include <linux/writeback.h>
  13#include <linux/pagevec.h>
  14#include <linux/prefetch.h>
  15#include <linux/cleancache.h>
 
  16#include "extent_io.h"
 
  17#include "extent_map.h"
  18#include "ctree.h"
  19#include "btrfs_inode.h"
  20#include "volumes.h"
  21#include "check-integrity.h"
  22#include "locking.h"
  23#include "rcu-string.h"
  24#include "backref.h"
  25#include "disk-io.h"
 
 
 
  26
  27static struct kmem_cache *extent_state_cache;
  28static struct kmem_cache *extent_buffer_cache;
  29static struct bio_set *btrfs_bioset;
  30
  31static inline bool extent_state_in_tree(const struct extent_state *state)
  32{
  33	return !RB_EMPTY_NODE(&state->rb_node);
  34}
  35
  36#ifdef CONFIG_BTRFS_DEBUG
  37static LIST_HEAD(buffers);
  38static LIST_HEAD(states);
  39
  40static DEFINE_SPINLOCK(leak_lock);
  41
  42static inline
  43void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
 
  44{
  45	unsigned long flags;
  46
  47	spin_lock_irqsave(&leak_lock, flags);
  48	list_add(new, head);
  49	spin_unlock_irqrestore(&leak_lock, flags);
  50}
  51
  52static inline
  53void btrfs_leak_debug_del(struct list_head *entry)
  54{
  55	unsigned long flags;
  56
  57	spin_lock_irqsave(&leak_lock, flags);
  58	list_del(entry);
  59	spin_unlock_irqrestore(&leak_lock, flags);
  60}
  61
  62static inline
  63void btrfs_leak_debug_check(void)
  64{
  65	struct extent_state *state;
  66	struct extent_buffer *eb;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  67
  68	while (!list_empty(&states)) {
  69		state = list_entry(states.next, struct extent_state, leak_list);
  70		pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
  71		       state->start, state->end, state->state,
  72		       extent_state_in_tree(state),
  73		       refcount_read(&state->refs));
  74		list_del(&state->leak_list);
  75		kmem_cache_free(extent_state_cache, state);
  76	}
  77
  78	while (!list_empty(&buffers)) {
  79		eb = list_entry(buffers.next, struct extent_buffer, leak_list);
  80		pr_err("BTRFS: buffer leak start %llu len %lu refs %d bflags %lu\n",
  81		       eb->start, eb->len, atomic_read(&eb->refs), eb->bflags);
  82		list_del(&eb->leak_list);
  83		kmem_cache_free(extent_buffer_cache, eb);
  84	}
  85}
  86
  87#define btrfs_debug_check_extent_io_range(tree, start, end)		\
  88	__btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
  89static inline void __btrfs_debug_check_extent_io_range(const char *caller,
  90		struct extent_io_tree *tree, u64 start, u64 end)
  91{
  92	if (tree->ops && tree->ops->check_extent_io_range)
  93		tree->ops->check_extent_io_range(tree->private_data, caller,
  94						 start, end);
 
 
 
 
 
 
 
 
 
  95}
  96#else
  97#define btrfs_leak_debug_add(new, head)	do {} while (0)
  98#define btrfs_leak_debug_del(entry)	do {} while (0)
  99#define btrfs_leak_debug_check()	do {} while (0)
 100#define btrfs_debug_check_extent_io_range(c, s, e)	do {} while (0)
 101#endif
 102
 103#define BUFFER_LRU_MAX 64
 104
 105struct tree_entry {
 106	u64 start;
 107	u64 end;
 108	struct rb_node rb_node;
 109};
 110
 111struct extent_page_data {
 112	struct bio *bio;
 113	struct extent_io_tree *tree;
 114	/* tells writepage not to lock the state bits for this range
 115	 * it still does the unlocking
 116	 */
 117	unsigned int extent_locked:1;
 118
 119	/* tells the submit_bio code to use REQ_SYNC */
 120	unsigned int sync_io:1;
 121};
 122
 123static int add_extent_changeset(struct extent_state *state, unsigned bits,
 124				 struct extent_changeset *changeset,
 125				 int set)
 126{
 127	int ret;
 128
 129	if (!changeset)
 130		return 0;
 131	if (set && (state->state & bits) == bits)
 132		return 0;
 133	if (!set && (state->state & bits) == 0)
 134		return 0;
 135	changeset->bytes_changed += state->end - state->start + 1;
 136	ret = ulist_add(&changeset->range_changed, state->start, state->end,
 137			GFP_ATOMIC);
 138	return ret;
 139}
 140
 141static void flush_write_bio(struct extent_page_data *epd);
 
 
 
 
 
 
 
 
 
 
 
 
 
 142
 143static inline struct btrfs_fs_info *
 144tree_fs_info(struct extent_io_tree *tree)
 
 
 
 145{
 146	if (tree->ops)
 147		return tree->ops->tree_fs_info(tree->private_data);
 148	return NULL;
 
 
 
 
 149}
 150
 151int __init extent_io_init(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 152{
 153	extent_state_cache = kmem_cache_create("btrfs_extent_state",
 154			sizeof(struct extent_state), 0,
 155			SLAB_MEM_SPREAD, NULL);
 156	if (!extent_state_cache)
 157		return -ENOMEM;
 
 
 158
 
 
 159	extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
 160			sizeof(struct extent_buffer), 0,
 161			SLAB_MEM_SPREAD, NULL);
 162	if (!extent_buffer_cache)
 163		goto free_state_cache;
 164
 165	btrfs_bioset = bioset_create(BIO_POOL_SIZE,
 166				     offsetof(struct btrfs_io_bio, bio),
 167				     BIOSET_NEED_BVECS);
 168	if (!btrfs_bioset)
 169		goto free_buffer_cache;
 170
 171	if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
 172		goto free_bioset;
 173
 174	return 0;
 175
 176free_bioset:
 177	bioset_free(btrfs_bioset);
 178	btrfs_bioset = NULL;
 179
 180free_buffer_cache:
 181	kmem_cache_destroy(extent_buffer_cache);
 182	extent_buffer_cache = NULL;
 
 
 183
 184free_state_cache:
 
 
 185	kmem_cache_destroy(extent_state_cache);
 186	extent_state_cache = NULL;
 187	return -ENOMEM;
 188}
 189
 190void __cold extent_io_exit(void)
 191{
 192	btrfs_leak_debug_check();
 193
 194	/*
 195	 * Make sure all delayed rcu free are flushed before we
 196	 * destroy caches.
 197	 */
 198	rcu_barrier();
 199	kmem_cache_destroy(extent_state_cache);
 200	kmem_cache_destroy(extent_buffer_cache);
 201	if (btrfs_bioset)
 202		bioset_free(btrfs_bioset);
 203}
 204
 205void extent_io_tree_init(struct extent_io_tree *tree,
 
 
 
 
 
 
 
 
 
 
 206			 void *private_data)
 207{
 
 208	tree->state = RB_ROOT;
 209	tree->ops = NULL;
 210	tree->dirty_bytes = 0;
 211	spin_lock_init(&tree->lock);
 212	tree->private_data = private_data;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 213}
 214
 215static struct extent_state *alloc_extent_state(gfp_t mask)
 216{
 217	struct extent_state *state;
 218
 219	/*
 220	 * The given mask might be not appropriate for the slab allocator,
 221	 * drop the unsupported bits
 222	 */
 223	mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
 224	state = kmem_cache_alloc(extent_state_cache, mask);
 225	if (!state)
 226		return state;
 227	state->state = 0;
 228	state->failrec = NULL;
 229	RB_CLEAR_NODE(&state->rb_node);
 230	btrfs_leak_debug_add(&state->leak_list, &states);
 231	refcount_set(&state->refs, 1);
 232	init_waitqueue_head(&state->wq);
 233	trace_alloc_extent_state(state, mask, _RET_IP_);
 234	return state;
 235}
 236
 237void free_extent_state(struct extent_state *state)
 238{
 239	if (!state)
 240		return;
 241	if (refcount_dec_and_test(&state->refs)) {
 242		WARN_ON(extent_state_in_tree(state));
 243		btrfs_leak_debug_del(&state->leak_list);
 244		trace_free_extent_state(state, _RET_IP_);
 245		kmem_cache_free(extent_state_cache, state);
 246	}
 247}
 248
 249static struct rb_node *tree_insert(struct rb_root *root,
 250				   struct rb_node *search_start,
 251				   u64 offset,
 252				   struct rb_node *node,
 253				   struct rb_node ***p_in,
 254				   struct rb_node **parent_in)
 255{
 256	struct rb_node **p;
 257	struct rb_node *parent = NULL;
 258	struct tree_entry *entry;
 259
 260	if (p_in && parent_in) {
 261		p = *p_in;
 262		parent = *parent_in;
 263		goto do_insert;
 264	}
 265
 266	p = search_start ? &search_start : &root->rb_node;
 267	while (*p) {
 268		parent = *p;
 269		entry = rb_entry(parent, struct tree_entry, rb_node);
 270
 271		if (offset < entry->start)
 272			p = &(*p)->rb_left;
 273		else if (offset > entry->end)
 274			p = &(*p)->rb_right;
 275		else
 276			return parent;
 277	}
 278
 279do_insert:
 280	rb_link_node(node, parent, p);
 281	rb_insert_color(node, root);
 282	return NULL;
 283}
 284
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 285static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
 286				      struct rb_node **prev_ret,
 287				      struct rb_node **next_ret,
 
 288				      struct rb_node ***p_ret,
 289				      struct rb_node **parent_ret)
 290{
 291	struct rb_root *root = &tree->state;
 292	struct rb_node **n = &root->rb_node;
 293	struct rb_node *prev = NULL;
 294	struct rb_node *orig_prev = NULL;
 295	struct tree_entry *entry;
 296	struct tree_entry *prev_entry = NULL;
 297
 298	while (*n) {
 299		prev = *n;
 300		entry = rb_entry(prev, struct tree_entry, rb_node);
 301		prev_entry = entry;
 302
 303		if (offset < entry->start)
 304			n = &(*n)->rb_left;
 305		else if (offset > entry->end)
 306			n = &(*n)->rb_right;
 307		else
 308			return *n;
 309	}
 310
 311	if (p_ret)
 312		*p_ret = n;
 313	if (parent_ret)
 314		*parent_ret = prev;
 315
 316	if (prev_ret) {
 317		orig_prev = prev;
 318		while (prev && offset > prev_entry->end) {
 319			prev = rb_next(prev);
 320			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 321		}
 322		*prev_ret = prev;
 323		prev = orig_prev;
 324	}
 325
 326	if (next_ret) {
 327		prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 328		while (prev && offset < prev_entry->start) {
 329			prev = rb_prev(prev);
 330			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
 331		}
 332		*next_ret = prev;
 333	}
 334	return NULL;
 335}
 336
 337static inline struct rb_node *
 338tree_search_for_insert(struct extent_io_tree *tree,
 339		       u64 offset,
 340		       struct rb_node ***p_ret,
 341		       struct rb_node **parent_ret)
 342{
 343	struct rb_node *prev = NULL;
 344	struct rb_node *ret;
 345
 346	ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
 347	if (!ret)
 348		return prev;
 349	return ret;
 350}
 351
 352static inline struct rb_node *tree_search(struct extent_io_tree *tree,
 353					  u64 offset)
 354{
 355	return tree_search_for_insert(tree, offset, NULL, NULL);
 356}
 357
 358static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
 359		     struct extent_state *other)
 360{
 361	if (tree->ops && tree->ops->merge_extent_hook)
 362		tree->ops->merge_extent_hook(tree->private_data, new, other);
 363}
 364
 365/*
 366 * utility function to look for merge candidates inside a given range.
 367 * Any extents with matching state are merged together into a single
 368 * extent in the tree.  Extents with EXTENT_IO in their state field
 369 * are not merged because the end_io handlers need to be able to do
 370 * operations on them without sleeping (or doing allocations/splits).
 371 *
 372 * This should be called with the tree lock held.
 373 */
 374static void merge_state(struct extent_io_tree *tree,
 375		        struct extent_state *state)
 376{
 377	struct extent_state *other;
 378	struct rb_node *other_node;
 379
 380	if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
 381		return;
 382
 383	other_node = rb_prev(&state->rb_node);
 384	if (other_node) {
 385		other = rb_entry(other_node, struct extent_state, rb_node);
 386		if (other->end == state->start - 1 &&
 387		    other->state == state->state) {
 388			merge_cb(tree, state, other);
 
 
 
 389			state->start = other->start;
 390			rb_erase(&other->rb_node, &tree->state);
 391			RB_CLEAR_NODE(&other->rb_node);
 392			free_extent_state(other);
 393		}
 394	}
 395	other_node = rb_next(&state->rb_node);
 396	if (other_node) {
 397		other = rb_entry(other_node, struct extent_state, rb_node);
 398		if (other->start == state->end + 1 &&
 399		    other->state == state->state) {
 400			merge_cb(tree, state, other);
 
 
 
 401			state->end = other->end;
 402			rb_erase(&other->rb_node, &tree->state);
 403			RB_CLEAR_NODE(&other->rb_node);
 404			free_extent_state(other);
 405		}
 406	}
 407}
 408
 409static void set_state_cb(struct extent_io_tree *tree,
 410			 struct extent_state *state, unsigned *bits)
 411{
 412	if (tree->ops && tree->ops->set_bit_hook)
 413		tree->ops->set_bit_hook(tree->private_data, state, bits);
 414}
 415
 416static void clear_state_cb(struct extent_io_tree *tree,
 417			   struct extent_state *state, unsigned *bits)
 418{
 419	if (tree->ops && tree->ops->clear_bit_hook)
 420		tree->ops->clear_bit_hook(tree->private_data, state, bits);
 421}
 422
 423static void set_state_bits(struct extent_io_tree *tree,
 424			   struct extent_state *state, unsigned *bits,
 425			   struct extent_changeset *changeset);
 426
 427/*
 428 * insert an extent_state struct into the tree.  'bits' are set on the
 429 * struct before it is inserted.
 430 *
 431 * This may return -EEXIST if the extent is already there, in which case the
 432 * state struct is freed.
 433 *
 434 * The tree lock is not taken internally.  This is a utility function and
 435 * probably isn't what you want to call (see set/clear_extent_bit).
 436 */
 437static int insert_state(struct extent_io_tree *tree,
 438			struct extent_state *state, u64 start, u64 end,
 439			struct rb_node ***p,
 440			struct rb_node **parent,
 441			unsigned *bits, struct extent_changeset *changeset)
 442{
 443	struct rb_node *node;
 444
 445	if (end < start)
 446		WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
 447		       end, start);
 
 
 448	state->start = start;
 449	state->end = end;
 450
 451	set_state_bits(tree, state, bits, changeset);
 452
 453	node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
 454	if (node) {
 455		struct extent_state *found;
 456		found = rb_entry(node, struct extent_state, rb_node);
 457		pr_err("BTRFS: found node %llu %llu on insert of %llu %llu\n",
 
 458		       found->start, found->end, start, end);
 459		return -EEXIST;
 460	}
 461	merge_state(tree, state);
 462	return 0;
 463}
 464
 465static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
 466		     u64 split)
 467{
 468	if (tree->ops && tree->ops->split_extent_hook)
 469		tree->ops->split_extent_hook(tree->private_data, orig, split);
 470}
 471
 472/*
 473 * split a given extent state struct in two, inserting the preallocated
 474 * struct 'prealloc' as the newly created second half.  'split' indicates an
 475 * offset inside 'orig' where it should be split.
 476 *
 477 * Before calling,
 478 * the tree has 'orig' at [orig->start, orig->end].  After calling, there
 479 * are two extent state structs in the tree:
 480 * prealloc: [orig->start, split - 1]
 481 * orig: [ split, orig->end ]
 482 *
 483 * The tree locks are not taken by this function. They need to be held
 484 * by the caller.
 485 */
 486static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 487		       struct extent_state *prealloc, u64 split)
 488{
 489	struct rb_node *node;
 490
 491	split_cb(tree, orig, split);
 
 492
 493	prealloc->start = orig->start;
 494	prealloc->end = split - 1;
 495	prealloc->state = orig->state;
 496	orig->start = split;
 497
 498	node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
 499			   &prealloc->rb_node, NULL, NULL);
 500	if (node) {
 501		free_extent_state(prealloc);
 502		return -EEXIST;
 503	}
 504	return 0;
 505}
 506
 507static struct extent_state *next_state(struct extent_state *state)
 508{
 509	struct rb_node *next = rb_next(&state->rb_node);
 510	if (next)
 511		return rb_entry(next, struct extent_state, rb_node);
 512	else
 513		return NULL;
 514}
 515
 516/*
 517 * utility function to clear some bits in an extent state struct.
 518 * it will optionally wake up any one waiting on this state (wake == 1).
 519 *
 520 * If no bits are set on the state struct after clearing things, the
 521 * struct is freed and removed from the tree
 522 */
 523static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
 524					    struct extent_state *state,
 525					    unsigned *bits, int wake,
 526					    struct extent_changeset *changeset)
 527{
 528	struct extent_state *next;
 529	unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
 530	int ret;
 531
 532	if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
 533		u64 range = state->end - state->start + 1;
 534		WARN_ON(range > tree->dirty_bytes);
 535		tree->dirty_bytes -= range;
 536	}
 537	clear_state_cb(tree, state, bits);
 
 
 
 538	ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
 539	BUG_ON(ret < 0);
 540	state->state &= ~bits_to_clear;
 541	if (wake)
 542		wake_up(&state->wq);
 543	if (state->state == 0) {
 544		next = next_state(state);
 545		if (extent_state_in_tree(state)) {
 546			rb_erase(&state->rb_node, &tree->state);
 547			RB_CLEAR_NODE(&state->rb_node);
 548			free_extent_state(state);
 549		} else {
 550			WARN_ON(1);
 551		}
 552	} else {
 553		merge_state(tree, state);
 554		next = next_state(state);
 555	}
 556	return next;
 557}
 558
 559static struct extent_state *
 560alloc_extent_state_atomic(struct extent_state *prealloc)
 561{
 562	if (!prealloc)
 563		prealloc = alloc_extent_state(GFP_ATOMIC);
 564
 565	return prealloc;
 566}
 567
 568static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
 569{
 570	btrfs_panic(tree_fs_info(tree), err,
 571		    "Locking error: Extent tree was modified by another thread while locked.");
 572}
 573
 574/*
 575 * clear some bits on a range in the tree.  This may require splitting
 576 * or inserting elements in the tree, so the gfp mask is used to
 577 * indicate which allocations or sleeping are allowed.
 578 *
 579 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
 580 * the given range from the tree regardless of state (ie for truncate).
 581 *
 582 * the range [start, end] is inclusive.
 583 *
 584 * This takes the tree lock, and returns 0 on success and < 0 on error.
 585 */
 586int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 587			      unsigned bits, int wake, int delete,
 588			      struct extent_state **cached_state,
 589			      gfp_t mask, struct extent_changeset *changeset)
 590{
 591	struct extent_state *state;
 592	struct extent_state *cached;
 593	struct extent_state *prealloc = NULL;
 594	struct rb_node *node;
 595	u64 last_end;
 596	int err;
 597	int clear = 0;
 598
 599	btrfs_debug_check_extent_io_range(tree, start, end);
 
 600
 601	if (bits & EXTENT_DELALLOC)
 602		bits |= EXTENT_NORESERVE;
 603
 604	if (delete)
 605		bits |= ~EXTENT_CTLBITS;
 606	bits |= EXTENT_FIRST_DELALLOC;
 607
 608	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
 609		clear = 1;
 610again:
 611	if (!prealloc && gfpflags_allow_blocking(mask)) {
 612		/*
 613		 * Don't care for allocation failure here because we might end
 614		 * up not needing the pre-allocated extent state at all, which
 615		 * is the case if we only have in the tree extent states that
 616		 * cover our input range and don't cover too any other range.
 617		 * If we end up needing a new extent state we allocate it later.
 618		 */
 619		prealloc = alloc_extent_state(mask);
 620	}
 621
 622	spin_lock(&tree->lock);
 623	if (cached_state) {
 624		cached = *cached_state;
 625
 626		if (clear) {
 627			*cached_state = NULL;
 628			cached_state = NULL;
 629		}
 630
 631		if (cached && extent_state_in_tree(cached) &&
 632		    cached->start <= start && cached->end > start) {
 633			if (clear)
 634				refcount_dec(&cached->refs);
 635			state = cached;
 636			goto hit_next;
 637		}
 638		if (clear)
 639			free_extent_state(cached);
 640	}
 641	/*
 642	 * this search will find the extents that end after
 643	 * our range starts
 644	 */
 645	node = tree_search(tree, start);
 646	if (!node)
 647		goto out;
 648	state = rb_entry(node, struct extent_state, rb_node);
 649hit_next:
 650	if (state->start > end)
 651		goto out;
 652	WARN_ON(state->end < start);
 653	last_end = state->end;
 654
 655	/* the state doesn't have the wanted bits, go ahead */
 656	if (!(state->state & bits)) {
 657		state = next_state(state);
 658		goto next;
 659	}
 660
 661	/*
 662	 *     | ---- desired range ---- |
 663	 *  | state | or
 664	 *  | ------------- state -------------- |
 665	 *
 666	 * We need to split the extent we found, and may flip
 667	 * bits on second half.
 668	 *
 669	 * If the extent we found extends past our range, we
 670	 * just split and search again.  It'll get split again
 671	 * the next time though.
 672	 *
 673	 * If the extent we found is inside our range, we clear
 674	 * the desired bit on it.
 675	 */
 676
 677	if (state->start < start) {
 678		prealloc = alloc_extent_state_atomic(prealloc);
 679		BUG_ON(!prealloc);
 680		err = split_state(tree, state, prealloc, start);
 681		if (err)
 682			extent_io_tree_panic(tree, err);
 683
 684		prealloc = NULL;
 685		if (err)
 686			goto out;
 687		if (state->end <= end) {
 688			state = clear_state_bit(tree, state, &bits, wake,
 689						changeset);
 690			goto next;
 691		}
 692		goto search_again;
 693	}
 694	/*
 695	 * | ---- desired range ---- |
 696	 *                        | state |
 697	 * We need to split the extent, and clear the bit
 698	 * on the first half
 699	 */
 700	if (state->start <= end && state->end > end) {
 701		prealloc = alloc_extent_state_atomic(prealloc);
 702		BUG_ON(!prealloc);
 703		err = split_state(tree, state, prealloc, end + 1);
 704		if (err)
 705			extent_io_tree_panic(tree, err);
 706
 707		if (wake)
 708			wake_up(&state->wq);
 709
 710		clear_state_bit(tree, prealloc, &bits, wake, changeset);
 711
 712		prealloc = NULL;
 713		goto out;
 714	}
 715
 716	state = clear_state_bit(tree, state, &bits, wake, changeset);
 717next:
 718	if (last_end == (u64)-1)
 719		goto out;
 720	start = last_end + 1;
 721	if (start <= end && state && !need_resched())
 722		goto hit_next;
 723
 724search_again:
 725	if (start > end)
 726		goto out;
 727	spin_unlock(&tree->lock);
 728	if (gfpflags_allow_blocking(mask))
 729		cond_resched();
 730	goto again;
 731
 732out:
 733	spin_unlock(&tree->lock);
 734	if (prealloc)
 735		free_extent_state(prealloc);
 736
 737	return 0;
 738
 739}
 740
 741static void wait_on_state(struct extent_io_tree *tree,
 742			  struct extent_state *state)
 743		__releases(tree->lock)
 744		__acquires(tree->lock)
 745{
 746	DEFINE_WAIT(wait);
 747	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
 748	spin_unlock(&tree->lock);
 749	schedule();
 750	spin_lock(&tree->lock);
 751	finish_wait(&state->wq, &wait);
 752}
 753
 754/*
 755 * waits for one or more bits to clear on a range in the state tree.
 756 * The range [start, end] is inclusive.
 757 * The tree lock is taken by this function
 758 */
 759static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 760			    unsigned long bits)
 761{
 762	struct extent_state *state;
 763	struct rb_node *node;
 764
 765	btrfs_debug_check_extent_io_range(tree, start, end);
 766
 767	spin_lock(&tree->lock);
 768again:
 769	while (1) {
 770		/*
 771		 * this search will find all the extents that end after
 772		 * our range starts
 773		 */
 774		node = tree_search(tree, start);
 775process_node:
 776		if (!node)
 777			break;
 778
 779		state = rb_entry(node, struct extent_state, rb_node);
 780
 781		if (state->start > end)
 782			goto out;
 783
 784		if (state->state & bits) {
 785			start = state->start;
 786			refcount_inc(&state->refs);
 787			wait_on_state(tree, state);
 788			free_extent_state(state);
 789			goto again;
 790		}
 791		start = state->end + 1;
 792
 793		if (start > end)
 794			break;
 795
 796		if (!cond_resched_lock(&tree->lock)) {
 797			node = rb_next(node);
 798			goto process_node;
 799		}
 800	}
 801out:
 802	spin_unlock(&tree->lock);
 803}
 804
 805static void set_state_bits(struct extent_io_tree *tree,
 806			   struct extent_state *state,
 807			   unsigned *bits, struct extent_changeset *changeset)
 808{
 809	unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
 810	int ret;
 811
 812	set_state_cb(tree, state, bits);
 
 
 813	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
 814		u64 range = state->end - state->start + 1;
 815		tree->dirty_bytes += range;
 816	}
 817	ret = add_extent_changeset(state, bits_to_set, changeset, 1);
 818	BUG_ON(ret < 0);
 819	state->state |= bits_to_set;
 820}
 821
 822static void cache_state_if_flags(struct extent_state *state,
 823				 struct extent_state **cached_ptr,
 824				 unsigned flags)
 825{
 826	if (cached_ptr && !(*cached_ptr)) {
 827		if (!flags || (state->state & flags)) {
 828			*cached_ptr = state;
 829			refcount_inc(&state->refs);
 830		}
 831	}
 832}
 833
 834static void cache_state(struct extent_state *state,
 835			struct extent_state **cached_ptr)
 836{
 837	return cache_state_if_flags(state, cached_ptr,
 838				    EXTENT_IOBITS | EXTENT_BOUNDARY);
 839}
 840
 841/*
 842 * set some bits on a range in the tree.  This may require allocations or
 843 * sleeping, so the gfp mask is used to indicate what is allowed.
 844 *
 845 * If any of the exclusive bits are set, this will fail with -EEXIST if some
 846 * part of the range already has the desired bits set.  The start of the
 847 * existing range is returned in failed_start in this case.
 848 *
 849 * [start, end] is inclusive This takes the tree lock.
 850 */
 851
 852static int __must_check
 853__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 854		 unsigned bits, unsigned exclusive_bits,
 855		 u64 *failed_start, struct extent_state **cached_state,
 856		 gfp_t mask, struct extent_changeset *changeset)
 857{
 858	struct extent_state *state;
 859	struct extent_state *prealloc = NULL;
 860	struct rb_node *node;
 861	struct rb_node **p;
 862	struct rb_node *parent;
 863	int err = 0;
 864	u64 last_start;
 865	u64 last_end;
 866
 867	btrfs_debug_check_extent_io_range(tree, start, end);
 
 868
 869	bits |= EXTENT_FIRST_DELALLOC;
 
 
 
 870again:
 871	if (!prealloc && gfpflags_allow_blocking(mask)) {
 872		/*
 873		 * Don't care for allocation failure here because we might end
 874		 * up not needing the pre-allocated extent state at all, which
 875		 * is the case if we only have in the tree extent states that
 876		 * cover our input range and don't cover too any other range.
 877		 * If we end up needing a new extent state we allocate it later.
 878		 */
 879		prealloc = alloc_extent_state(mask);
 880	}
 881
 882	spin_lock(&tree->lock);
 883	if (cached_state && *cached_state) {
 884		state = *cached_state;
 885		if (state->start <= start && state->end > start &&
 886		    extent_state_in_tree(state)) {
 887			node = &state->rb_node;
 888			goto hit_next;
 889		}
 890	}
 891	/*
 892	 * this search will find all the extents that end after
 893	 * our range starts.
 894	 */
 895	node = tree_search_for_insert(tree, start, &p, &parent);
 896	if (!node) {
 897		prealloc = alloc_extent_state_atomic(prealloc);
 898		BUG_ON(!prealloc);
 899		err = insert_state(tree, prealloc, start, end,
 900				   &p, &parent, &bits, changeset);
 901		if (err)
 902			extent_io_tree_panic(tree, err);
 903
 904		cache_state(prealloc, cached_state);
 905		prealloc = NULL;
 906		goto out;
 907	}
 908	state = rb_entry(node, struct extent_state, rb_node);
 909hit_next:
 910	last_start = state->start;
 911	last_end = state->end;
 912
 913	/*
 914	 * | ---- desired range ---- |
 915	 * | state |
 916	 *
 917	 * Just lock what we found and keep going
 918	 */
 919	if (state->start == start && state->end <= end) {
 920		if (state->state & exclusive_bits) {
 921			*failed_start = state->start;
 922			err = -EEXIST;
 923			goto out;
 924		}
 925
 926		set_state_bits(tree, state, &bits, changeset);
 927		cache_state(state, cached_state);
 928		merge_state(tree, state);
 929		if (last_end == (u64)-1)
 930			goto out;
 931		start = last_end + 1;
 932		state = next_state(state);
 933		if (start < end && state && state->start == start &&
 934		    !need_resched())
 935			goto hit_next;
 936		goto search_again;
 937	}
 938
 939	/*
 940	 *     | ---- desired range ---- |
 941	 * | state |
 942	 *   or
 943	 * | ------------- state -------------- |
 944	 *
 945	 * We need to split the extent we found, and may flip bits on
 946	 * second half.
 947	 *
 948	 * If the extent we found extends past our
 949	 * range, we just split and search again.  It'll get split
 950	 * again the next time though.
 951	 *
 952	 * If the extent we found is inside our range, we set the
 953	 * desired bit on it.
 954	 */
 955	if (state->start < start) {
 956		if (state->state & exclusive_bits) {
 957			*failed_start = start;
 958			err = -EEXIST;
 959			goto out;
 960		}
 961
 
 
 
 
 
 
 
 
 
 
 962		prealloc = alloc_extent_state_atomic(prealloc);
 963		BUG_ON(!prealloc);
 964		err = split_state(tree, state, prealloc, start);
 965		if (err)
 966			extent_io_tree_panic(tree, err);
 967
 968		prealloc = NULL;
 969		if (err)
 970			goto out;
 971		if (state->end <= end) {
 972			set_state_bits(tree, state, &bits, changeset);
 973			cache_state(state, cached_state);
 974			merge_state(tree, state);
 975			if (last_end == (u64)-1)
 976				goto out;
 977			start = last_end + 1;
 978			state = next_state(state);
 979			if (start < end && state && state->start == start &&
 980			    !need_resched())
 981				goto hit_next;
 982		}
 983		goto search_again;
 984	}
 985	/*
 986	 * | ---- desired range ---- |
 987	 *     | state | or               | state |
 988	 *
 989	 * There's a hole, we need to insert something in it and
 990	 * ignore the extent we found.
 991	 */
 992	if (state->start > start) {
 993		u64 this_end;
 994		if (end < last_start)
 995			this_end = end;
 996		else
 997			this_end = last_start - 1;
 998
 999		prealloc = alloc_extent_state_atomic(prealloc);
1000		BUG_ON(!prealloc);
1001
1002		/*
1003		 * Avoid to free 'prealloc' if it can be merged with
1004		 * the later extent.
1005		 */
1006		err = insert_state(tree, prealloc, start, this_end,
1007				   NULL, NULL, &bits, changeset);
1008		if (err)
1009			extent_io_tree_panic(tree, err);
1010
1011		cache_state(prealloc, cached_state);
1012		prealloc = NULL;
1013		start = this_end + 1;
1014		goto search_again;
1015	}
1016	/*
1017	 * | ---- desired range ---- |
1018	 *                        | state |
1019	 * We need to split the extent, and set the bit
1020	 * on the first half
1021	 */
1022	if (state->start <= end && state->end > end) {
1023		if (state->state & exclusive_bits) {
1024			*failed_start = start;
1025			err = -EEXIST;
1026			goto out;
1027		}
1028
1029		prealloc = alloc_extent_state_atomic(prealloc);
1030		BUG_ON(!prealloc);
1031		err = split_state(tree, state, prealloc, end + 1);
1032		if (err)
1033			extent_io_tree_panic(tree, err);
1034
1035		set_state_bits(tree, prealloc, &bits, changeset);
1036		cache_state(prealloc, cached_state);
1037		merge_state(tree, prealloc);
1038		prealloc = NULL;
1039		goto out;
1040	}
1041
1042search_again:
1043	if (start > end)
1044		goto out;
1045	spin_unlock(&tree->lock);
1046	if (gfpflags_allow_blocking(mask))
1047		cond_resched();
1048	goto again;
1049
1050out:
1051	spin_unlock(&tree->lock);
1052	if (prealloc)
1053		free_extent_state(prealloc);
1054
1055	return err;
1056
1057}
1058
1059int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1060		   unsigned bits, u64 * failed_start,
1061		   struct extent_state **cached_state, gfp_t mask)
1062{
1063	return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1064				cached_state, mask, NULL);
1065}
1066
1067
1068/**
1069 * convert_extent_bit - convert all bits in a given range from one bit to
1070 * 			another
1071 * @tree:	the io tree to search
1072 * @start:	the start offset in bytes
1073 * @end:	the end offset in bytes (inclusive)
1074 * @bits:	the bits to set in this range
1075 * @clear_bits:	the bits to clear in this range
1076 * @cached_state:	state that we're going to cache
1077 *
1078 * This will go through and set bits for the given range.  If any states exist
1079 * already in this range they are set with the given bit and cleared of the
1080 * clear_bits.  This is only meant to be used by things that are mergeable, ie
1081 * converting from say DELALLOC to DIRTY.  This is not meant to be used with
1082 * boundary bits like LOCK.
1083 *
1084 * All allocations are done with GFP_NOFS.
1085 */
1086int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1087		       unsigned bits, unsigned clear_bits,
1088		       struct extent_state **cached_state)
1089{
1090	struct extent_state *state;
1091	struct extent_state *prealloc = NULL;
1092	struct rb_node *node;
1093	struct rb_node **p;
1094	struct rb_node *parent;
1095	int err = 0;
1096	u64 last_start;
1097	u64 last_end;
1098	bool first_iteration = true;
1099
1100	btrfs_debug_check_extent_io_range(tree, start, end);
 
 
1101
1102again:
1103	if (!prealloc) {
1104		/*
1105		 * Best effort, don't worry if extent state allocation fails
1106		 * here for the first iteration. We might have a cached state
1107		 * that matches exactly the target range, in which case no
1108		 * extent state allocations are needed. We'll only know this
1109		 * after locking the tree.
1110		 */
1111		prealloc = alloc_extent_state(GFP_NOFS);
1112		if (!prealloc && !first_iteration)
1113			return -ENOMEM;
1114	}
1115
1116	spin_lock(&tree->lock);
1117	if (cached_state && *cached_state) {
1118		state = *cached_state;
1119		if (state->start <= start && state->end > start &&
1120		    extent_state_in_tree(state)) {
1121			node = &state->rb_node;
1122			goto hit_next;
1123		}
1124	}
1125
1126	/*
1127	 * this search will find all the extents that end after
1128	 * our range starts.
1129	 */
1130	node = tree_search_for_insert(tree, start, &p, &parent);
1131	if (!node) {
1132		prealloc = alloc_extent_state_atomic(prealloc);
1133		if (!prealloc) {
1134			err = -ENOMEM;
1135			goto out;
1136		}
1137		err = insert_state(tree, prealloc, start, end,
1138				   &p, &parent, &bits, NULL);
1139		if (err)
1140			extent_io_tree_panic(tree, err);
1141		cache_state(prealloc, cached_state);
1142		prealloc = NULL;
1143		goto out;
1144	}
1145	state = rb_entry(node, struct extent_state, rb_node);
1146hit_next:
1147	last_start = state->start;
1148	last_end = state->end;
1149
1150	/*
1151	 * | ---- desired range ---- |
1152	 * | state |
1153	 *
1154	 * Just lock what we found and keep going
1155	 */
1156	if (state->start == start && state->end <= end) {
1157		set_state_bits(tree, state, &bits, NULL);
1158		cache_state(state, cached_state);
1159		state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1160		if (last_end == (u64)-1)
1161			goto out;
1162		start = last_end + 1;
1163		if (start < end && state && state->start == start &&
1164		    !need_resched())
1165			goto hit_next;
1166		goto search_again;
1167	}
1168
1169	/*
1170	 *     | ---- desired range ---- |
1171	 * | state |
1172	 *   or
1173	 * | ------------- state -------------- |
1174	 *
1175	 * We need to split the extent we found, and may flip bits on
1176	 * second half.
1177	 *
1178	 * If the extent we found extends past our
1179	 * range, we just split and search again.  It'll get split
1180	 * again the next time though.
1181	 *
1182	 * If the extent we found is inside our range, we set the
1183	 * desired bit on it.
1184	 */
1185	if (state->start < start) {
1186		prealloc = alloc_extent_state_atomic(prealloc);
1187		if (!prealloc) {
1188			err = -ENOMEM;
1189			goto out;
1190		}
1191		err = split_state(tree, state, prealloc, start);
1192		if (err)
1193			extent_io_tree_panic(tree, err);
1194		prealloc = NULL;
1195		if (err)
1196			goto out;
1197		if (state->end <= end) {
1198			set_state_bits(tree, state, &bits, NULL);
1199			cache_state(state, cached_state);
1200			state = clear_state_bit(tree, state, &clear_bits, 0,
1201						NULL);
1202			if (last_end == (u64)-1)
1203				goto out;
1204			start = last_end + 1;
1205			if (start < end && state && state->start == start &&
1206			    !need_resched())
1207				goto hit_next;
1208		}
1209		goto search_again;
1210	}
1211	/*
1212	 * | ---- desired range ---- |
1213	 *     | state | or               | state |
1214	 *
1215	 * There's a hole, we need to insert something in it and
1216	 * ignore the extent we found.
1217	 */
1218	if (state->start > start) {
1219		u64 this_end;
1220		if (end < last_start)
1221			this_end = end;
1222		else
1223			this_end = last_start - 1;
1224
1225		prealloc = alloc_extent_state_atomic(prealloc);
1226		if (!prealloc) {
1227			err = -ENOMEM;
1228			goto out;
1229		}
1230
1231		/*
1232		 * Avoid to free 'prealloc' if it can be merged with
1233		 * the later extent.
1234		 */
1235		err = insert_state(tree, prealloc, start, this_end,
1236				   NULL, NULL, &bits, NULL);
1237		if (err)
1238			extent_io_tree_panic(tree, err);
1239		cache_state(prealloc, cached_state);
1240		prealloc = NULL;
1241		start = this_end + 1;
1242		goto search_again;
1243	}
1244	/*
1245	 * | ---- desired range ---- |
1246	 *                        | state |
1247	 * We need to split the extent, and set the bit
1248	 * on the first half
1249	 */
1250	if (state->start <= end && state->end > end) {
1251		prealloc = alloc_extent_state_atomic(prealloc);
1252		if (!prealloc) {
1253			err = -ENOMEM;
1254			goto out;
1255		}
1256
1257		err = split_state(tree, state, prealloc, end + 1);
1258		if (err)
1259			extent_io_tree_panic(tree, err);
1260
1261		set_state_bits(tree, prealloc, &bits, NULL);
1262		cache_state(prealloc, cached_state);
1263		clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1264		prealloc = NULL;
1265		goto out;
1266	}
1267
1268search_again:
1269	if (start > end)
1270		goto out;
1271	spin_unlock(&tree->lock);
1272	cond_resched();
1273	first_iteration = false;
1274	goto again;
1275
1276out:
1277	spin_unlock(&tree->lock);
1278	if (prealloc)
1279		free_extent_state(prealloc);
1280
1281	return err;
1282}
1283
1284/* wrappers around set/clear extent bit */
1285int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1286			   unsigned bits, struct extent_changeset *changeset)
1287{
1288	/*
1289	 * We don't support EXTENT_LOCKED yet, as current changeset will
1290	 * record any bits changed, so for EXTENT_LOCKED case, it will
1291	 * either fail with -EEXIST or changeset will record the whole
1292	 * range.
1293	 */
1294	BUG_ON(bits & EXTENT_LOCKED);
1295
1296	return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
1297				changeset);
 
 
 
 
 
 
 
1298}
1299
1300int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1301		     unsigned bits, int wake, int delete,
1302		     struct extent_state **cached)
1303{
1304	return __clear_extent_bit(tree, start, end, bits, wake, delete,
1305				  cached, GFP_NOFS, NULL);
1306}
1307
1308int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1309		unsigned bits, struct extent_changeset *changeset)
1310{
1311	/*
1312	 * Don't support EXTENT_LOCKED case, same reason as
1313	 * set_record_extent_bits().
1314	 */
1315	BUG_ON(bits & EXTENT_LOCKED);
1316
1317	return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
1318				  changeset);
1319}
1320
1321/*
1322 * either insert or lock state struct between start and end use mask to tell
1323 * us if waiting is desired.
1324 */
1325int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1326		     struct extent_state **cached_state)
1327{
1328	int err;
1329	u64 failed_start;
1330
1331	while (1) {
1332		err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
1333				       EXTENT_LOCKED, &failed_start,
1334				       cached_state, GFP_NOFS, NULL);
1335		if (err == -EEXIST) {
1336			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1337			start = failed_start;
1338		} else
1339			break;
1340		WARN_ON(start > end);
1341	}
1342	return err;
1343}
1344
1345int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1346{
1347	int err;
1348	u64 failed_start;
1349
1350	err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1351			       &failed_start, NULL, GFP_NOFS, NULL);
1352	if (err == -EEXIST) {
1353		if (failed_start > start)
1354			clear_extent_bit(tree, start, failed_start - 1,
1355					 EXTENT_LOCKED, 1, 0, NULL);
1356		return 0;
1357	}
1358	return 1;
1359}
1360
1361void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1362{
1363	unsigned long index = start >> PAGE_SHIFT;
1364	unsigned long end_index = end >> PAGE_SHIFT;
1365	struct page *page;
1366
1367	while (index <= end_index) {
1368		page = find_get_page(inode->i_mapping, index);
1369		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1370		clear_page_dirty_for_io(page);
1371		put_page(page);
1372		index++;
1373	}
1374}
1375
1376void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1377{
1378	unsigned long index = start >> PAGE_SHIFT;
1379	unsigned long end_index = end >> PAGE_SHIFT;
1380	struct page *page;
1381
1382	while (index <= end_index) {
1383		page = find_get_page(inode->i_mapping, index);
1384		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1385		__set_page_dirty_nobuffers(page);
1386		account_page_redirty(page);
1387		put_page(page);
1388		index++;
1389	}
1390}
1391
1392/*
1393 * helper function to set both pages and extents in the tree writeback
1394 */
1395static void set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1396{
1397	tree->ops->set_range_writeback(tree->private_data, start, end);
1398}
1399
1400/* find the first state struct with 'bits' set after 'start', and
1401 * return it.  tree->lock must be held.  NULL will returned if
1402 * nothing was found after 'start'
1403 */
1404static struct extent_state *
1405find_first_extent_bit_state(struct extent_io_tree *tree,
1406			    u64 start, unsigned bits)
1407{
1408	struct rb_node *node;
1409	struct extent_state *state;
1410
1411	/*
1412	 * this search will find all the extents that end after
1413	 * our range starts.
1414	 */
1415	node = tree_search(tree, start);
1416	if (!node)
1417		goto out;
1418
1419	while (1) {
1420		state = rb_entry(node, struct extent_state, rb_node);
1421		if (state->end >= start && (state->state & bits))
1422			return state;
1423
1424		node = rb_next(node);
1425		if (!node)
1426			break;
1427	}
1428out:
1429	return NULL;
1430}
1431
1432/*
1433 * find the first offset in the io tree with 'bits' set. zero is
1434 * returned if we find something, and *start_ret and *end_ret are
1435 * set to reflect the state struct that was found.
1436 *
1437 * If nothing was found, 1 is returned. If found something, return 0.
 
1438 */
1439int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1440			  u64 *start_ret, u64 *end_ret, unsigned bits,
1441			  struct extent_state **cached_state)
1442{
1443	struct extent_state *state;
1444	struct rb_node *n;
1445	int ret = 1;
1446
1447	spin_lock(&tree->lock);
1448	if (cached_state && *cached_state) {
1449		state = *cached_state;
1450		if (state->end == start - 1 && extent_state_in_tree(state)) {
1451			n = rb_next(&state->rb_node);
1452			while (n) {
1453				state = rb_entry(n, struct extent_state,
1454						 rb_node);
1455				if (state->state & bits)
1456					goto got_it;
1457				n = rb_next(n);
1458			}
1459			free_extent_state(*cached_state);
1460			*cached_state = NULL;
1461			goto out;
1462		}
1463		free_extent_state(*cached_state);
1464		*cached_state = NULL;
1465	}
1466
1467	state = find_first_extent_bit_state(tree, start, bits);
1468got_it:
1469	if (state) {
1470		cache_state_if_flags(state, cached_state, 0);
1471		*start_ret = state->start;
1472		*end_ret = state->end;
1473		ret = 0;
1474	}
1475out:
1476	spin_unlock(&tree->lock);
1477	return ret;
1478}
1479
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1480/*
1481 * find a contiguous range of bytes in the file marked as delalloc, not
1482 * more than 'max_bytes'.  start and end are used to return the range,
1483 *
1484 * 1 is returned if we find something, 0 if nothing was in the tree
1485 */
1486static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1487					u64 *start, u64 *end, u64 max_bytes,
1488					struct extent_state **cached_state)
1489{
1490	struct rb_node *node;
1491	struct extent_state *state;
1492	u64 cur_start = *start;
1493	u64 found = 0;
1494	u64 total_bytes = 0;
1495
1496	spin_lock(&tree->lock);
1497
1498	/*
1499	 * this search will find all the extents that end after
1500	 * our range starts.
1501	 */
1502	node = tree_search(tree, cur_start);
1503	if (!node) {
1504		if (!found)
1505			*end = (u64)-1;
1506		goto out;
1507	}
1508
1509	while (1) {
1510		state = rb_entry(node, struct extent_state, rb_node);
1511		if (found && (state->start != cur_start ||
1512			      (state->state & EXTENT_BOUNDARY))) {
1513			goto out;
1514		}
1515		if (!(state->state & EXTENT_DELALLOC)) {
1516			if (!found)
1517				*end = state->end;
1518			goto out;
1519		}
1520		if (!found) {
1521			*start = state->start;
1522			*cached_state = state;
1523			refcount_inc(&state->refs);
1524		}
1525		found++;
1526		*end = state->end;
1527		cur_start = state->end + 1;
1528		node = rb_next(node);
1529		total_bytes += state->end - state->start + 1;
1530		if (total_bytes >= max_bytes)
1531			break;
1532		if (!node)
1533			break;
1534	}
1535out:
1536	spin_unlock(&tree->lock);
1537	return found;
1538}
1539
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1540static int __process_pages_contig(struct address_space *mapping,
1541				  struct page *locked_page,
1542				  pgoff_t start_index, pgoff_t end_index,
1543				  unsigned long page_ops, pgoff_t *index_ret);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1544
1545static noinline void __unlock_for_delalloc(struct inode *inode,
1546					   struct page *locked_page,
1547					   u64 start, u64 end)
1548{
1549	unsigned long index = start >> PAGE_SHIFT;
1550	unsigned long end_index = end >> PAGE_SHIFT;
1551
1552	ASSERT(locked_page);
1553	if (index == locked_page->index && end_index == index)
1554		return;
1555
1556	__process_pages_contig(inode->i_mapping, locked_page, index, end_index,
1557			       PAGE_UNLOCK, NULL);
1558}
1559
1560static noinline int lock_delalloc_pages(struct inode *inode,
1561					struct page *locked_page,
1562					u64 delalloc_start,
1563					u64 delalloc_end)
1564{
1565	unsigned long index = delalloc_start >> PAGE_SHIFT;
1566	unsigned long index_ret = index;
1567	unsigned long end_index = delalloc_end >> PAGE_SHIFT;
 
1568	int ret;
1569
1570	ASSERT(locked_page);
1571	if (index == locked_page->index && index == end_index)
1572		return 0;
1573
1574	ret = __process_pages_contig(inode->i_mapping, locked_page, index,
1575				     end_index, PAGE_LOCK, &index_ret);
1576	if (ret == -EAGAIN)
1577		__unlock_for_delalloc(inode, locked_page, delalloc_start,
1578				      (u64)index_ret << PAGE_SHIFT);
1579	return ret;
1580}
1581
1582/*
1583 * find a contiguous range of bytes in the file marked as delalloc, not
1584 * more than 'max_bytes'.  start and end are used to return the range,
1585 *
1586 * 1 is returned if we find something, 0 if nothing was in the tree
 
1587 */
1588STATIC u64 find_lock_delalloc_range(struct inode *inode,
1589				    struct extent_io_tree *tree,
1590				    struct page *locked_page, u64 *start,
1591				    u64 *end, u64 max_bytes)
1592{
 
 
1593	u64 delalloc_start;
1594	u64 delalloc_end;
1595	u64 found;
1596	struct extent_state *cached_state = NULL;
1597	int ret;
1598	int loops = 0;
1599
1600again:
1601	/* step one, find a bunch of delalloc bytes starting at start */
1602	delalloc_start = *start;
1603	delalloc_end = 0;
1604	found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1605				    max_bytes, &cached_state);
1606	if (!found || delalloc_end <= *start) {
1607		*start = delalloc_start;
1608		*end = delalloc_end;
1609		free_extent_state(cached_state);
1610		return 0;
1611	}
1612
1613	/*
1614	 * start comes from the offset of locked_page.  We have to lock
1615	 * pages in order, so we can't process delalloc bytes before
1616	 * locked_page
1617	 */
1618	if (delalloc_start < *start)
1619		delalloc_start = *start;
1620
1621	/*
1622	 * make sure to limit the number of pages we try to lock down
1623	 */
1624	if (delalloc_end + 1 - delalloc_start > max_bytes)
1625		delalloc_end = delalloc_start + max_bytes - 1;
1626
1627	/* step two, lock all the pages after the page that has start */
1628	ret = lock_delalloc_pages(inode, locked_page,
1629				  delalloc_start, delalloc_end);
 
1630	if (ret == -EAGAIN) {
1631		/* some of the pages are gone, lets avoid looping by
1632		 * shortening the size of the delalloc range we're searching
1633		 */
1634		free_extent_state(cached_state);
1635		cached_state = NULL;
1636		if (!loops) {
1637			max_bytes = PAGE_SIZE;
1638			loops = 1;
1639			goto again;
1640		} else {
1641			found = 0;
1642			goto out_failed;
1643		}
1644	}
1645	BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1646
1647	/* step three, lock the state bits for the whole range */
1648	lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1649
1650	/* then test to make sure it is all still delalloc */
1651	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1652			     EXTENT_DELALLOC, 1, cached_state);
1653	if (!ret) {
1654		unlock_extent_cached(tree, delalloc_start, delalloc_end,
1655				     &cached_state);
1656		__unlock_for_delalloc(inode, locked_page,
1657			      delalloc_start, delalloc_end);
1658		cond_resched();
1659		goto again;
1660	}
1661	free_extent_state(cached_state);
1662	*start = delalloc_start;
1663	*end = delalloc_end;
1664out_failed:
1665	return found;
1666}
1667
1668static int __process_pages_contig(struct address_space *mapping,
1669				  struct page *locked_page,
1670				  pgoff_t start_index, pgoff_t end_index,
1671				  unsigned long page_ops, pgoff_t *index_ret)
1672{
1673	unsigned long nr_pages = end_index - start_index + 1;
1674	unsigned long pages_locked = 0;
1675	pgoff_t index = start_index;
1676	struct page *pages[16];
1677	unsigned ret;
1678	int err = 0;
1679	int i;
1680
1681	if (page_ops & PAGE_LOCK) {
1682		ASSERT(page_ops == PAGE_LOCK);
1683		ASSERT(index_ret && *index_ret == start_index);
1684	}
1685
1686	if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1687		mapping_set_error(mapping, -EIO);
1688
1689	while (nr_pages > 0) {
1690		ret = find_get_pages_contig(mapping, index,
1691				     min_t(unsigned long,
1692				     nr_pages, ARRAY_SIZE(pages)), pages);
1693		if (ret == 0) {
1694			/*
1695			 * Only if we're going to lock these pages,
1696			 * can we find nothing at @index.
1697			 */
1698			ASSERT(page_ops & PAGE_LOCK);
1699			err = -EAGAIN;
1700			goto out;
1701		}
1702
1703		for (i = 0; i < ret; i++) {
1704			if (page_ops & PAGE_SET_PRIVATE2)
1705				SetPagePrivate2(pages[i]);
1706
1707			if (pages[i] == locked_page) {
1708				put_page(pages[i]);
1709				pages_locked++;
1710				continue;
1711			}
1712			if (page_ops & PAGE_CLEAR_DIRTY)
1713				clear_page_dirty_for_io(pages[i]);
1714			if (page_ops & PAGE_SET_WRITEBACK)
1715				set_page_writeback(pages[i]);
1716			if (page_ops & PAGE_SET_ERROR)
1717				SetPageError(pages[i]);
1718			if (page_ops & PAGE_END_WRITEBACK)
1719				end_page_writeback(pages[i]);
1720			if (page_ops & PAGE_UNLOCK)
1721				unlock_page(pages[i]);
1722			if (page_ops & PAGE_LOCK) {
1723				lock_page(pages[i]);
1724				if (!PageDirty(pages[i]) ||
1725				    pages[i]->mapping != mapping) {
1726					unlock_page(pages[i]);
1727					put_page(pages[i]);
1728					err = -EAGAIN;
1729					goto out;
1730				}
1731			}
1732			put_page(pages[i]);
1733			pages_locked++;
1734		}
1735		nr_pages -= ret;
1736		index += ret;
1737		cond_resched();
1738	}
1739out:
1740	if (err && index_ret)
1741		*index_ret = start_index + pages_locked - 1;
1742	return err;
1743}
1744
1745void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1746				 u64 delalloc_end, struct page *locked_page,
1747				 unsigned clear_bits,
1748				 unsigned long page_ops)
1749{
1750	clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, clear_bits, 1, 0,
1751			 NULL);
1752
1753	__process_pages_contig(inode->i_mapping, locked_page,
1754			       start >> PAGE_SHIFT, end >> PAGE_SHIFT,
1755			       page_ops, NULL);
1756}
1757
1758/*
1759 * count the number of bytes in the tree that have a given bit(s)
1760 * set.  This can be fairly slow, except for EXTENT_DIRTY which is
1761 * cached.  The total number found is returned.
1762 */
1763u64 count_range_bits(struct extent_io_tree *tree,
1764		     u64 *start, u64 search_end, u64 max_bytes,
1765		     unsigned bits, int contig)
1766{
1767	struct rb_node *node;
1768	struct extent_state *state;
1769	u64 cur_start = *start;
1770	u64 total_bytes = 0;
1771	u64 last = 0;
1772	int found = 0;
1773
1774	if (WARN_ON(search_end <= cur_start))
1775		return 0;
1776
1777	spin_lock(&tree->lock);
1778	if (cur_start == 0 && bits == EXTENT_DIRTY) {
1779		total_bytes = tree->dirty_bytes;
1780		goto out;
1781	}
1782	/*
1783	 * this search will find all the extents that end after
1784	 * our range starts.
1785	 */
1786	node = tree_search(tree, cur_start);
1787	if (!node)
1788		goto out;
1789
1790	while (1) {
1791		state = rb_entry(node, struct extent_state, rb_node);
1792		if (state->start > search_end)
1793			break;
1794		if (contig && found && state->start > last + 1)
1795			break;
1796		if (state->end >= cur_start && (state->state & bits) == bits) {
1797			total_bytes += min(search_end, state->end) + 1 -
1798				       max(cur_start, state->start);
1799			if (total_bytes >= max_bytes)
1800				break;
1801			if (!found) {
1802				*start = max(cur_start, state->start);
1803				found = 1;
1804			}
1805			last = state->end;
1806		} else if (contig && found) {
1807			break;
1808		}
1809		node = rb_next(node);
1810		if (!node)
1811			break;
1812	}
1813out:
1814	spin_unlock(&tree->lock);
1815	return total_bytes;
1816}
1817
1818/*
1819 * set the private field for a given byte offset in the tree.  If there isn't
1820 * an extent_state there already, this does nothing.
1821 */
1822static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
1823		struct io_failure_record *failrec)
1824{
1825	struct rb_node *node;
1826	struct extent_state *state;
1827	int ret = 0;
1828
1829	spin_lock(&tree->lock);
1830	/*
1831	 * this search will find all the extents that end after
1832	 * our range starts.
1833	 */
1834	node = tree_search(tree, start);
1835	if (!node) {
1836		ret = -ENOENT;
1837		goto out;
1838	}
1839	state = rb_entry(node, struct extent_state, rb_node);
1840	if (state->start != start) {
1841		ret = -ENOENT;
1842		goto out;
1843	}
1844	state->failrec = failrec;
1845out:
1846	spin_unlock(&tree->lock);
1847	return ret;
1848}
1849
1850static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
1851		struct io_failure_record **failrec)
1852{
1853	struct rb_node *node;
1854	struct extent_state *state;
1855	int ret = 0;
1856
1857	spin_lock(&tree->lock);
1858	/*
1859	 * this search will find all the extents that end after
1860	 * our range starts.
1861	 */
1862	node = tree_search(tree, start);
1863	if (!node) {
1864		ret = -ENOENT;
1865		goto out;
1866	}
1867	state = rb_entry(node, struct extent_state, rb_node);
1868	if (state->start != start) {
1869		ret = -ENOENT;
1870		goto out;
1871	}
1872	*failrec = state->failrec;
 
1873out:
1874	spin_unlock(&tree->lock);
1875	return ret;
1876}
1877
1878/*
1879 * searches a range in the state tree for a given mask.
1880 * If 'filled' == 1, this returns 1 only if every extent in the tree
1881 * has the bits set.  Otherwise, 1 is returned if any bit in the
1882 * range is found set.
1883 */
1884int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1885		   unsigned bits, int filled, struct extent_state *cached)
1886{
1887	struct extent_state *state = NULL;
1888	struct rb_node *node;
1889	int bitset = 0;
1890
1891	spin_lock(&tree->lock);
1892	if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1893	    cached->end > start)
1894		node = &cached->rb_node;
1895	else
1896		node = tree_search(tree, start);
1897	while (node && start <= end) {
1898		state = rb_entry(node, struct extent_state, rb_node);
1899
1900		if (filled && state->start > start) {
1901			bitset = 0;
1902			break;
1903		}
1904
1905		if (state->start > end)
1906			break;
1907
1908		if (state->state & bits) {
1909			bitset = 1;
1910			if (!filled)
1911				break;
1912		} else if (filled) {
1913			bitset = 0;
1914			break;
1915		}
1916
1917		if (state->end == (u64)-1)
1918			break;
1919
1920		start = state->end + 1;
1921		if (start > end)
1922			break;
1923		node = rb_next(node);
1924		if (!node) {
1925			if (filled)
1926				bitset = 0;
1927			break;
1928		}
1929	}
1930	spin_unlock(&tree->lock);
1931	return bitset;
1932}
1933
1934/*
1935 * helper function to set a given page up to date if all the
1936 * extents in the tree for that page are up to date
1937 */
1938static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1939{
1940	u64 start = page_offset(page);
1941	u64 end = start + PAGE_SIZE - 1;
1942	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1943		SetPageUptodate(page);
1944}
1945
1946int free_io_failure(struct extent_io_tree *failure_tree,
1947		    struct extent_io_tree *io_tree,
1948		    struct io_failure_record *rec)
1949{
1950	int ret;
1951	int err = 0;
1952
1953	set_state_failrec(failure_tree, rec->start, NULL);
1954	ret = clear_extent_bits(failure_tree, rec->start,
1955				rec->start + rec->len - 1,
1956				EXTENT_LOCKED | EXTENT_DIRTY);
1957	if (ret)
1958		err = ret;
1959
1960	ret = clear_extent_bits(io_tree, rec->start,
1961				rec->start + rec->len - 1,
1962				EXTENT_DAMAGED);
1963	if (ret && !err)
1964		err = ret;
1965
1966	kfree(rec);
1967	return err;
1968}
1969
1970/*
1971 * this bypasses the standard btrfs submit functions deliberately, as
1972 * the standard behavior is to write all copies in a raid setup. here we only
1973 * want to write the one bad copy. so we do the mapping for ourselves and issue
1974 * submit_bio directly.
1975 * to avoid any synchronization issues, wait for the data after writing, which
1976 * actually prevents the read that triggered the error from finishing.
1977 * currently, there can be no more than two copies of every data bit. thus,
1978 * exactly one rewrite is required.
1979 */
1980int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
1981		      u64 length, u64 logical, struct page *page,
1982		      unsigned int pg_offset, int mirror_num)
1983{
1984	struct bio *bio;
1985	struct btrfs_device *dev;
1986	u64 map_length = 0;
1987	u64 sector;
1988	struct btrfs_bio *bbio = NULL;
1989	int ret;
1990
1991	ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
1992	BUG_ON(!mirror_num);
1993
 
 
 
1994	bio = btrfs_io_bio_alloc(1);
1995	bio->bi_iter.bi_size = 0;
1996	map_length = length;
1997
1998	/*
1999	 * Avoid races with device replace and make sure our bbio has devices
2000	 * associated to its stripes that don't go away while we are doing the
2001	 * read repair operation.
2002	 */
2003	btrfs_bio_counter_inc_blocked(fs_info);
2004	if (btrfs_is_parity_mirror(fs_info, logical, length)) {
2005		/*
2006		 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
2007		 * to update all raid stripes, but here we just want to correct
2008		 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
2009		 * stripe's dev and sector.
2010		 */
2011		ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
2012				      &map_length, &bbio, 0);
2013		if (ret) {
2014			btrfs_bio_counter_dec(fs_info);
2015			bio_put(bio);
2016			return -EIO;
2017		}
2018		ASSERT(bbio->mirror_num == 1);
2019	} else {
2020		ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
2021				      &map_length, &bbio, mirror_num);
2022		if (ret) {
2023			btrfs_bio_counter_dec(fs_info);
2024			bio_put(bio);
2025			return -EIO;
2026		}
2027		BUG_ON(mirror_num != bbio->mirror_num);
2028	}
2029
2030	sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
2031	bio->bi_iter.bi_sector = sector;
2032	dev = bbio->stripes[bbio->mirror_num - 1].dev;
2033	btrfs_put_bbio(bbio);
2034	if (!dev || !dev->bdev ||
2035	    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
2036		btrfs_bio_counter_dec(fs_info);
2037		bio_put(bio);
2038		return -EIO;
2039	}
2040	bio_set_dev(bio, dev->bdev);
2041	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
2042	bio_add_page(bio, page, length, pg_offset);
2043
2044	if (btrfsic_submit_bio_wait(bio)) {
2045		/* try to remap that extent elsewhere? */
2046		btrfs_bio_counter_dec(fs_info);
2047		bio_put(bio);
2048		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2049		return -EIO;
2050	}
2051
2052	btrfs_info_rl_in_rcu(fs_info,
2053		"read error corrected: ino %llu off %llu (dev %s sector %llu)",
2054				  ino, start,
2055				  rcu_str_deref(dev->name), sector);
2056	btrfs_bio_counter_dec(fs_info);
2057	bio_put(bio);
2058	return 0;
2059}
2060
2061int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
2062			 struct extent_buffer *eb, int mirror_num)
2063{
 
2064	u64 start = eb->start;
2065	unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2066	int ret = 0;
2067
2068	if (sb_rdonly(fs_info->sb))
2069		return -EROFS;
2070
2071	for (i = 0; i < num_pages; i++) {
2072		struct page *p = eb->pages[i];
2073
2074		ret = repair_io_failure(fs_info, 0, start, PAGE_SIZE, start, p,
2075					start - page_offset(p), mirror_num);
2076		if (ret)
2077			break;
2078		start += PAGE_SIZE;
2079	}
2080
2081	return ret;
2082}
2083
2084/*
2085 * each time an IO finishes, we do a fast check in the IO failure tree
2086 * to see if we need to process or clean up an io_failure_record
2087 */
2088int clean_io_failure(struct btrfs_fs_info *fs_info,
2089		     struct extent_io_tree *failure_tree,
2090		     struct extent_io_tree *io_tree, u64 start,
2091		     struct page *page, u64 ino, unsigned int pg_offset)
2092{
2093	u64 private;
2094	struct io_failure_record *failrec;
2095	struct extent_state *state;
2096	int num_copies;
2097	int ret;
2098
2099	private = 0;
2100	ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
2101			       EXTENT_DIRTY, 0);
2102	if (!ret)
2103		return 0;
2104
2105	ret = get_state_failrec(failure_tree, start, &failrec);
2106	if (ret)
2107		return 0;
2108
2109	BUG_ON(!failrec->this_mirror);
2110
2111	if (failrec->in_validation) {
2112		/* there was no real error, just free the record */
2113		btrfs_debug(fs_info,
2114			"clean_io_failure: freeing dummy error at %llu",
2115			failrec->start);
2116		goto out;
2117	}
2118	if (sb_rdonly(fs_info->sb))
2119		goto out;
2120
2121	spin_lock(&io_tree->lock);
2122	state = find_first_extent_bit_state(io_tree,
2123					    failrec->start,
2124					    EXTENT_LOCKED);
2125	spin_unlock(&io_tree->lock);
2126
2127	if (state && state->start <= failrec->start &&
2128	    state->end >= failrec->start + failrec->len - 1) {
2129		num_copies = btrfs_num_copies(fs_info, failrec->logical,
2130					      failrec->len);
2131		if (num_copies > 1)  {
2132			repair_io_failure(fs_info, ino, start, failrec->len,
2133					  failrec->logical, page, pg_offset,
2134					  failrec->failed_mirror);
2135		}
2136	}
2137
2138out:
2139	free_io_failure(failure_tree, io_tree, failrec);
2140
2141	return 0;
2142}
2143
2144/*
2145 * Can be called when
2146 * - hold extent lock
2147 * - under ordered extent
2148 * - the inode is freeing
2149 */
2150void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
2151{
2152	struct extent_io_tree *failure_tree = &inode->io_failure_tree;
2153	struct io_failure_record *failrec;
2154	struct extent_state *state, *next;
2155
2156	if (RB_EMPTY_ROOT(&failure_tree->state))
2157		return;
2158
2159	spin_lock(&failure_tree->lock);
2160	state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2161	while (state) {
2162		if (state->start > end)
2163			break;
2164
2165		ASSERT(state->end <= end);
2166
2167		next = next_state(state);
2168
2169		failrec = state->failrec;
2170		free_extent_state(state);
2171		kfree(failrec);
2172
2173		state = next;
2174	}
2175	spin_unlock(&failure_tree->lock);
2176}
2177
2178int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2179		struct io_failure_record **failrec_ret)
2180{
2181	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2182	struct io_failure_record *failrec;
2183	struct extent_map *em;
2184	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2185	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2186	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 
2187	int ret;
2188	u64 logical;
2189
2190	ret = get_state_failrec(failure_tree, start, &failrec);
2191	if (ret) {
2192		failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2193		if (!failrec)
2194			return -ENOMEM;
 
 
 
 
 
2195
2196		failrec->start = start;
2197		failrec->len = end - start + 1;
2198		failrec->this_mirror = 0;
2199		failrec->bio_flags = 0;
2200		failrec->in_validation = 0;
2201
2202		read_lock(&em_tree->lock);
2203		em = lookup_extent_mapping(em_tree, start, failrec->len);
2204		if (!em) {
2205			read_unlock(&em_tree->lock);
2206			kfree(failrec);
2207			return -EIO;
2208		}
2209
2210		if (em->start > start || em->start + em->len <= start) {
2211			free_extent_map(em);
2212			em = NULL;
2213		}
 
 
 
 
2214		read_unlock(&em_tree->lock);
2215		if (!em) {
2216			kfree(failrec);
2217			return -EIO;
2218		}
2219
2220		logical = start - em->start;
2221		logical = em->block_start + logical;
2222		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2223			logical = em->block_start;
2224			failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2225			extent_set_compress_type(&failrec->bio_flags,
2226						 em->compress_type);
2227		}
2228
2229		btrfs_debug(fs_info,
2230			"Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2231			logical, start, failrec->len);
2232
2233		failrec->logical = logical;
2234		free_extent_map(em);
 
 
 
 
 
 
 
2235
2236		/* set the bits in the private failure tree */
2237		ret = set_extent_bits(failure_tree, start, end,
2238					EXTENT_LOCKED | EXTENT_DIRTY);
2239		if (ret >= 0)
2240			ret = set_state_failrec(failure_tree, start, failrec);
2241		/* set the bits in the inode's tree */
2242		if (ret >= 0)
2243			ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
2244		if (ret < 0) {
2245			kfree(failrec);
2246			return ret;
2247		}
2248	} else {
2249		btrfs_debug(fs_info,
2250			"Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2251			failrec->logical, failrec->start, failrec->len,
2252			failrec->in_validation);
2253		/*
2254		 * when data can be on disk more than twice, add to failrec here
2255		 * (e.g. with a list for failed_mirror) to make
2256		 * clean_io_failure() clean all those errors at once.
2257		 */
2258	}
2259
2260	*failrec_ret = failrec;
 
 
2261
2262	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2263}
2264
2265bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
2266			   struct io_failure_record *failrec, int failed_mirror)
 
2267{
2268	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2269	int num_copies;
2270
2271	num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
2272	if (num_copies == 1) {
2273		/*
2274		 * we only have a single copy of the data, so don't bother with
2275		 * all the retry and error correction code that follows. no
2276		 * matter what the error is, it is very likely to persist.
2277		 */
2278		btrfs_debug(fs_info,
2279			"Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2280			num_copies, failrec->this_mirror, failed_mirror);
2281		return false;
2282	}
2283
 
 
 
2284	/*
2285	 * there are two premises:
2286	 *	a) deliver good data to the caller
2287	 *	b) correct the bad sectors on disk
2288	 */
2289	if (failed_bio_pages > 1) {
2290		/*
2291		 * to fulfill b), we need to know the exact failing sectors, as
2292		 * we don't want to rewrite any more than the failed ones. thus,
2293		 * we need separate read requests for the failed bio
2294		 *
2295		 * if the following BUG_ON triggers, our validation request got
2296		 * merged. we need separate requests for our algorithm to work.
2297		 */
2298		BUG_ON(failrec->in_validation);
2299		failrec->in_validation = 1;
2300		failrec->this_mirror = failed_mirror;
2301	} else {
2302		/*
2303		 * we're ready to fulfill a) and b) alongside. get a good copy
2304		 * of the failed sector and if we succeed, we have setup
2305		 * everything for repair_io_failure to do the rest for us.
2306		 */
2307		if (failrec->in_validation) {
2308			BUG_ON(failrec->this_mirror != failed_mirror);
2309			failrec->in_validation = 0;
2310			failrec->this_mirror = 0;
2311		}
2312		failrec->failed_mirror = failed_mirror;
2313		failrec->this_mirror++;
2314		if (failrec->this_mirror == failed_mirror)
2315			failrec->this_mirror++;
2316	}
2317
2318	if (failrec->this_mirror > num_copies) {
2319		btrfs_debug(fs_info,
2320			"Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2321			num_copies, failrec->this_mirror, failed_mirror);
2322		return false;
2323	}
2324
2325	return true;
2326}
2327
2328
2329struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2330				    struct io_failure_record *failrec,
2331				    struct page *page, int pg_offset, int icsum,
2332				    bio_end_io_t *endio_func, void *data)
2333{
2334	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2335	struct bio *bio;
2336	struct btrfs_io_bio *btrfs_failed_bio;
2337	struct btrfs_io_bio *btrfs_bio;
2338
2339	bio = btrfs_io_bio_alloc(1);
2340	bio->bi_end_io = endio_func;
2341	bio->bi_iter.bi_sector = failrec->logical >> 9;
2342	bio_set_dev(bio, fs_info->fs_devices->latest_bdev);
2343	bio->bi_iter.bi_size = 0;
2344	bio->bi_private = data;
2345
2346	btrfs_failed_bio = btrfs_io_bio(failed_bio);
2347	if (btrfs_failed_bio->csum) {
2348		u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2349
2350		btrfs_bio = btrfs_io_bio(bio);
2351		btrfs_bio->csum = btrfs_bio->csum_inline;
2352		icsum *= csum_size;
2353		memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2354		       csum_size);
2355	}
2356
2357	bio_add_page(bio, page, failrec->len, pg_offset);
2358
2359	return bio;
2360}
2361
2362/*
2363 * this is a generic handler for readpage errors (default
2364 * readpage_io_failed_hook). if other copies exist, read those and write back
2365 * good data to the failed position. does not investigate in remapping the
2366 * failed extent elsewhere, hoping the device will be smart enough to do this as
2367 * needed
2368 */
2369
2370static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2371			      struct page *page, u64 start, u64 end,
2372			      int failed_mirror)
2373{
2374	struct io_failure_record *failrec;
2375	struct inode *inode = page->mapping->host;
2376	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2377	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2378	struct bio *bio;
2379	int read_mode = 0;
 
 
2380	blk_status_t status;
2381	int ret;
2382	unsigned failed_bio_pages = bio_pages_all(failed_bio);
 
2383
2384	BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
2385
2386	ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2387	if (ret)
2388		return ret;
 
2389
2390	if (!btrfs_check_repairable(inode, failed_bio_pages, failrec,
2391				    failed_mirror)) {
2392		free_io_failure(failure_tree, tree, failrec);
2393		return -EIO;
2394	}
2395
2396	if (failed_bio_pages > 1)
2397		read_mode |= REQ_FAILFAST_DEV;
2398
2399	phy_offset >>= inode->i_sb->s_blocksize_bits;
2400	bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2401				      start - page_offset(page),
2402				      (int)phy_offset, failed_bio->bi_end_io,
2403				      NULL);
2404	bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
 
 
 
 
 
 
 
 
 
2405
2406	btrfs_debug(btrfs_sb(inode->i_sb),
2407		"Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
2408		read_mode, failrec->this_mirror, failrec->in_validation);
2409
2410	status = tree->ops->submit_bio_hook(tree->private_data, bio, failrec->this_mirror,
2411					 failrec->bio_flags, 0);
2412	if (status) {
2413		free_io_failure(failure_tree, tree, failrec);
2414		bio_put(bio);
2415		ret = blk_status_to_errno(status);
2416	}
 
 
2417
2418	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2419}
2420
2421/* lots and lots of room for performance fixes in the end_bio funcs */
2422
2423void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2424{
 
2425	int uptodate = (err == 0);
2426	struct extent_io_tree *tree;
2427	int ret = 0;
2428
2429	tree = &BTRFS_I(page->mapping->host)->io_tree;
2430
2431	if (tree->ops && tree->ops->writepage_end_io_hook)
2432		tree->ops->writepage_end_io_hook(page, start, end, NULL,
2433				uptodate);
2434
2435	if (!uptodate) {
2436		ClearPageUptodate(page);
2437		SetPageError(page);
2438		ret = err < 0 ? err : -EIO;
2439		mapping_set_error(page->mapping, ret);
2440	}
2441}
2442
2443/*
2444 * after a writepage IO is done, we need to:
2445 * clear the uptodate bits on error
2446 * clear the writeback bits in the extent tree for this IO
2447 * end_page_writeback if the page has no more pending IO
2448 *
2449 * Scheduling is not allowed, so the extent state tree is expected
2450 * to have one and only one object corresponding to this IO.
2451 */
2452static void end_bio_extent_writepage(struct bio *bio)
2453{
2454	int error = blk_status_to_errno(bio->bi_status);
2455	struct bio_vec *bvec;
2456	u64 start;
2457	u64 end;
2458	int i;
 
2459
2460	ASSERT(!bio_flagged(bio, BIO_CLONED));
2461	bio_for_each_segment_all(bvec, bio, i) {
2462		struct page *page = bvec->bv_page;
2463		struct inode *inode = page->mapping->host;
2464		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 
2465
2466		/* We always issue full-page reads, but if some block
2467		 * in a page fails to read, blk_update_request() will
2468		 * advance bv_offset and adjust bv_len to compensate.
2469		 * Print a warning for nonzero offsets, and an error
2470		 * if they don't add up to a full page.  */
2471		if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2472			if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2473				btrfs_err(fs_info,
2474				   "partial page write in btrfs with offset %u and length %u",
2475					bvec->bv_offset, bvec->bv_len);
2476			else
2477				btrfs_info(fs_info,
2478				   "incomplete page write in btrfs with offset %u and length %u",
2479					bvec->bv_offset, bvec->bv_len);
 
 
2480		}
2481
2482		start = page_offset(page);
2483		end = start + bvec->bv_offset + bvec->bv_len - 1;
2484
2485		end_extent_writepage(page, error, start, end);
2486		end_page_writeback(page);
 
2487	}
2488
2489	bio_put(bio);
2490}
2491
2492static void
2493endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2494			      int uptodate)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2495{
2496	struct extent_state *cached = NULL;
2497	u64 end = start + len - 1;
 
 
 
 
2498
2499	if (uptodate && tree->track_uptodate)
2500		set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2501	unlock_extent_cached_atomic(tree, start, end, &cached);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2502}
2503
2504/*
2505 * after a readpage IO is done, we need to:
2506 * clear the uptodate bits on error
2507 * set the uptodate bits if things worked
2508 * set the page up to date if all extents in the tree are uptodate
2509 * clear the lock bit in the extent tree
2510 * unlock the page if there are no other extents locked for it
2511 *
2512 * Scheduling is not allowed, so the extent state tree is expected
2513 * to have one and only one object corresponding to this IO.
2514 */
2515static void end_bio_extent_readpage(struct bio *bio)
2516{
2517	struct bio_vec *bvec;
2518	int uptodate = !bio->bi_status;
2519	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2520	struct extent_io_tree *tree, *failure_tree;
2521	u64 offset = 0;
2522	u64 start;
2523	u64 end;
2524	u64 len;
2525	u64 extent_start = 0;
2526	u64 extent_len = 0;
2527	int mirror;
2528	int ret;
2529	int i;
2530
2531	ASSERT(!bio_flagged(bio, BIO_CLONED));
2532	bio_for_each_segment_all(bvec, bio, i) {
 
2533		struct page *page = bvec->bv_page;
2534		struct inode *inode = page->mapping->host;
2535		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 
 
 
 
 
2536
2537		btrfs_debug(fs_info,
2538			"end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2539			(u64)bio->bi_iter.bi_sector, bio->bi_status,
2540			io_bio->mirror_num);
2541		tree = &BTRFS_I(inode)->io_tree;
2542		failure_tree = &BTRFS_I(inode)->io_failure_tree;
2543
2544		/* We always issue full-page reads, but if some block
2545		 * in a page fails to read, blk_update_request() will
2546		 * advance bv_offset and adjust bv_len to compensate.
2547		 * Print a warning for nonzero offsets, and an error
2548		 * if they don't add up to a full page.  */
2549		if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2550			if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2551				btrfs_err(fs_info,
2552					"partial page read in btrfs with offset %u and length %u",
2553					bvec->bv_offset, bvec->bv_len);
2554			else
2555				btrfs_info(fs_info,
2556					"incomplete page read in btrfs with offset %u and length %u",
2557					bvec->bv_offset, bvec->bv_len);
2558		}
 
2559
2560		start = page_offset(page);
2561		end = start + bvec->bv_offset + bvec->bv_len - 1;
2562		len = bvec->bv_len;
2563
2564		mirror = io_bio->mirror_num;
2565		if (likely(uptodate && tree->ops)) {
2566			ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2567							      page, start, end,
2568							      mirror);
 
 
 
 
 
2569			if (ret)
2570				uptodate = 0;
2571			else
2572				clean_io_failure(BTRFS_I(inode)->root->fs_info,
2573						 failure_tree, tree, start,
2574						 page,
2575						 btrfs_ino(BTRFS_I(inode)), 0);
2576		}
2577
2578		if (likely(uptodate))
2579			goto readpage_ok;
2580
2581		if (tree->ops) {
2582			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2583			if (ret == -EAGAIN) {
2584				/*
2585				 * Data inode's readpage_io_failed_hook() always
2586				 * returns -EAGAIN.
2587				 *
2588				 * The generic bio_readpage_error handles errors
2589				 * the following way: If possible, new read
2590				 * requests are created and submitted and will
2591				 * end up in end_bio_extent_readpage as well (if
2592				 * we're lucky, not in the !uptodate case). In
2593				 * that case it returns 0 and we just go on with
2594				 * the next page in our bio. If it can't handle
2595				 * the error it will return -EIO and we remain
2596				 * responsible for that page.
2597				 */
2598				ret = bio_readpage_error(bio, offset, page,
2599							 start, end, mirror);
2600				if (ret == 0) {
2601					uptodate = !bio->bi_status;
2602					offset += len;
2603					continue;
2604				}
2605			}
2606
2607			/*
2608			 * metadata's readpage_io_failed_hook() always returns
2609			 * -EIO and fixes nothing.  -EIO is also returned if
2610			 * data inode error could not be fixed.
2611			 */
2612			ASSERT(ret == -EIO);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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, blk_status_to_errno(bio->bi_status));
 
 
 
2660	bio_put(bio);
2661}
2662
2663/*
2664 * Initialize the members up to but not including 'bio'. Use after allocating a
2665 * new bio by bio_alloc_bioset as it does not initialize the bytes outside of
2666 * 'bio' because use of __GFP_ZERO is not supported.
2667 */
2668static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
2669{
2670	memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
2671}
2672
2673/*
2674 * The following helpers allocate a bio. As it's backed by a bioset, it'll
2675 * never fail.  We're returning a bio right now but you can call btrfs_io_bio
2676 * for the appropriate container_of magic
2677 */
2678struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte)
2679{
2680	struct bio *bio;
2681
2682	bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, btrfs_bioset);
2683	bio_set_dev(bio, bdev);
2684	bio->bi_iter.bi_sector = first_byte >> 9;
2685	btrfs_io_bio_init(btrfs_io_bio(bio));
2686	return bio;
2687}
2688
2689struct bio *btrfs_bio_clone(struct bio *bio)
2690{
2691	struct btrfs_io_bio *btrfs_bio;
2692	struct bio *new;
2693
2694	/* Bio allocation backed by a bioset does not fail */
2695	new = bio_clone_fast(bio, GFP_NOFS, btrfs_bioset);
2696	btrfs_bio = btrfs_io_bio(new);
2697	btrfs_io_bio_init(btrfs_bio);
2698	btrfs_bio->iter = bio->bi_iter;
2699	return new;
2700}
2701
2702struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs)
2703{
2704	struct bio *bio;
2705
2706	/* Bio allocation backed by a bioset does not fail */
2707	bio = bio_alloc_bioset(GFP_NOFS, nr_iovecs, btrfs_bioset);
2708	btrfs_io_bio_init(btrfs_io_bio(bio));
2709	return bio;
2710}
2711
2712struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
2713{
2714	struct bio *bio;
2715	struct btrfs_io_bio *btrfs_bio;
2716
2717	/* this will never fail when it's backed by a bioset */
2718	bio = bio_clone_fast(orig, GFP_NOFS, btrfs_bioset);
2719	ASSERT(bio);
2720
2721	btrfs_bio = btrfs_io_bio(bio);
2722	btrfs_io_bio_init(btrfs_bio);
2723
2724	bio_trim(bio, offset >> 9, size >> 9);
2725	btrfs_bio->iter = bio->bi_iter;
2726	return bio;
2727}
2728
2729static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
2730				       unsigned long bio_flags)
2731{
2732	blk_status_t ret = 0;
2733	struct bio_vec *bvec = bio_last_bvec_all(bio);
2734	struct page *page = bvec->bv_page;
2735	struct extent_io_tree *tree = bio->bi_private;
2736	u64 start;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2737
2738	start = page_offset(page) + bvec->bv_offset;
 
 
 
 
2739
2740	bio->bi_private = NULL;
 
 
 
 
 
 
 
 
 
2741
2742	if (tree->ops)
2743		ret = tree->ops->submit_bio_hook(tree->private_data, bio,
2744					   mirror_num, bio_flags, start);
2745	else
2746		btrfsic_submit_bio(bio);
2747
2748	return blk_status_to_errno(ret);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2749}
2750
2751/*
2752 * @opf:	bio REQ_OP_* and REQ_* flags as one value
2753 * @tree:	tree so we can call our merge_bio hook
2754 * @wbc:	optional writeback control for io accounting
2755 * @page:	page to add to the bio
 
 
2756 * @pg_offset:	offset of the new bio or to check whether we are adding
2757 *              a contiguous page to the previous one
2758 * @size:	portion of page that we want to write
2759 * @offset:	starting offset in the page
2760 * @bdev:	attach newly created bios to this bdev
2761 * @bio_ret:	must be valid pointer, newly allocated bio will be stored there
2762 * @end_io_func:     end_io callback for new bio
2763 * @mirror_num:	     desired mirror to read/write
2764 * @prev_bio_flags:  flags of previous bio to see if we can merge the current one
2765 * @bio_flags:	flags of the current bio to see if we can merge them
2766 */
2767static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
2768			      struct writeback_control *wbc,
2769			      struct page *page, u64 offset,
 
2770			      size_t size, unsigned long pg_offset,
2771			      struct block_device *bdev,
2772			      struct bio **bio_ret,
2773			      bio_end_io_t end_io_func,
2774			      int mirror_num,
2775			      unsigned long prev_bio_flags,
2776			      unsigned long bio_flags,
2777			      bool force_bio_submit)
2778{
2779	int ret = 0;
2780	struct bio *bio;
2781	size_t page_size = min_t(size_t, size, PAGE_SIZE);
2782	sector_t sector = offset >> 9;
2783
2784	ASSERT(bio_ret);
2785
2786	if (*bio_ret) {
2787		bool contig;
2788		bool can_merge = true;
2789
2790		bio = *bio_ret;
2791		if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
2792			contig = bio->bi_iter.bi_sector == sector;
2793		else
2794			contig = bio_end_sector(bio) == sector;
2795
2796		if (tree->ops && tree->ops->merge_bio_hook(page, offset,
2797					page_size, bio, bio_flags))
2798			can_merge = false;
2799
2800		if (prev_bio_flags != bio_flags || !contig || !can_merge ||
2801		    force_bio_submit ||
2802		    bio_add_page(bio, page, page_size, pg_offset) < page_size) {
2803			ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
2804			if (ret < 0) {
2805				*bio_ret = NULL;
2806				return ret;
2807			}
2808			bio = NULL;
2809		} else {
2810			if (wbc)
2811				wbc_account_io(wbc, page, page_size);
2812			return 0;
2813		}
2814	}
2815
2816	bio = btrfs_bio_alloc(bdev, offset);
2817	bio_add_page(bio, page, page_size, pg_offset);
2818	bio->bi_end_io = end_io_func;
2819	bio->bi_private = tree;
2820	bio->bi_write_hint = page->mapping->host->i_write_hint;
2821	bio->bi_opf = opf;
2822	if (wbc) {
 
 
 
 
2823		wbc_init_bio(wbc, bio);
2824		wbc_account_io(wbc, page, page_size);
 
 
 
 
 
 
 
 
 
2825	}
2826
2827	*bio_ret = bio;
 
 
2828
2829	return ret;
2830}
2831
2832static void attach_extent_buffer_page(struct extent_buffer *eb,
2833				      struct page *page)
 
2834{
2835	if (!PagePrivate(page)) {
2836		SetPagePrivate(page);
2837		get_page(page);
2838		set_page_private(page, (unsigned long)eb);
2839	} else {
2840		WARN_ON(page->private != (unsigned long)eb);
 
 
 
 
 
 
 
 
 
 
 
 
2841	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2842}
2843
2844void set_page_extent_mapped(struct page *page)
2845{
2846	if (!PagePrivate(page)) {
2847		SetPagePrivate(page);
2848		get_page(page);
2849		set_page_private(page, EXTENT_PAGE_PRIVATE);
2850	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2851}
2852
2853static struct extent_map *
2854__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
2855		 u64 start, u64 len, get_extent_t *get_extent,
2856		 struct extent_map **em_cached)
2857{
2858	struct extent_map *em;
2859
2860	if (em_cached && *em_cached) {
2861		em = *em_cached;
2862		if (extent_map_in_tree(em) && start >= em->start &&
2863		    start < extent_map_end(em)) {
2864			refcount_inc(&em->refs);
2865			return em;
2866		}
2867
2868		free_extent_map(em);
2869		*em_cached = NULL;
2870	}
2871
2872	em = get_extent(BTRFS_I(inode), page, pg_offset, start, len, 0);
2873	if (em_cached && !IS_ERR_OR_NULL(em)) {
2874		BUG_ON(*em_cached);
2875		refcount_inc(&em->refs);
2876		*em_cached = em;
2877	}
2878	return em;
2879}
2880/*
2881 * basic readpage implementation.  Locked extent state structs are inserted
2882 * into the tree that are removed when the IO is done (by the end_io
2883 * handlers)
2884 * XXX JDM: This needs looking at to ensure proper page locking
2885 * return 0 on success, otherwise return error
2886 */
2887static int __do_readpage(struct extent_io_tree *tree,
2888			 struct page *page,
2889			 get_extent_t *get_extent,
2890			 struct extent_map **em_cached,
2891			 struct bio **bio, int mirror_num,
2892			 unsigned long *bio_flags, unsigned int read_flags,
2893			 u64 *prev_em_start)
2894{
2895	struct inode *inode = page->mapping->host;
 
2896	u64 start = page_offset(page);
2897	const u64 end = start + PAGE_SIZE - 1;
2898	u64 cur = start;
2899	u64 extent_offset;
2900	u64 last_byte = i_size_read(inode);
2901	u64 block_start;
2902	u64 cur_end;
2903	struct extent_map *em;
2904	struct block_device *bdev;
2905	int ret = 0;
2906	int nr = 0;
2907	size_t pg_offset = 0;
2908	size_t iosize;
2909	size_t disk_io_size;
2910	size_t blocksize = inode->i_sb->s_blocksize;
2911	unsigned long this_bio_flag = 0;
 
2912
2913	set_page_extent_mapped(page);
 
 
 
 
 
 
2914
2915	if (!PageUptodate(page)) {
2916		if (cleancache_get_page(page) == 0) {
2917			BUG_ON(blocksize != PAGE_SIZE);
2918			unlock_extent(tree, start, end);
 
2919			goto out;
2920		}
2921	}
2922
2923	if (page->index == last_byte >> PAGE_SHIFT) {
2924		char *userpage;
2925		size_t zero_offset = last_byte & (PAGE_SIZE - 1);
2926
2927		if (zero_offset) {
2928			iosize = PAGE_SIZE - zero_offset;
2929			userpage = kmap_atomic(page);
2930			memset(userpage + zero_offset, 0, iosize);
2931			flush_dcache_page(page);
2932			kunmap_atomic(userpage);
2933		}
2934	}
 
2935	while (cur <= end) {
2936		bool force_bio_submit = false;
2937		u64 offset;
2938
2939		if (cur >= last_byte) {
2940			char *userpage;
2941			struct extent_state *cached = NULL;
2942
2943			iosize = PAGE_SIZE - pg_offset;
2944			userpage = kmap_atomic(page);
2945			memset(userpage + pg_offset, 0, iosize);
2946			flush_dcache_page(page);
2947			kunmap_atomic(userpage);
2948			set_extent_uptodate(tree, cur, cur + iosize - 1,
2949					    &cached, GFP_NOFS);
2950			unlock_extent_cached(tree, cur,
2951					     cur + iosize - 1, &cached);
 
2952			break;
2953		}
2954		em = __get_extent_map(inode, page, pg_offset, cur,
2955				      end - cur + 1, get_extent, em_cached);
2956		if (IS_ERR_OR_NULL(em)) {
2957			SetPageError(page);
2958			unlock_extent(tree, cur, end);
 
2959			break;
2960		}
2961		extent_offset = cur - em->start;
2962		BUG_ON(extent_map_end(em) <= cur);
2963		BUG_ON(end < cur);
2964
2965		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2966			this_bio_flag |= EXTENT_BIO_COMPRESSED;
2967			extent_set_compress_type(&this_bio_flag,
2968						 em->compress_type);
2969		}
2970
2971		iosize = min(extent_map_end(em) - cur, end - cur + 1);
2972		cur_end = min(extent_map_end(em) - 1, end);
2973		iosize = ALIGN(iosize, blocksize);
2974		if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2975			disk_io_size = em->block_len;
2976			offset = em->block_start;
2977		} else {
2978			offset = em->block_start + extent_offset;
2979			disk_io_size = iosize;
2980		}
2981		bdev = em->bdev;
2982		block_start = em->block_start;
2983		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2984			block_start = EXTENT_MAP_HOLE;
2985
2986		/*
2987		 * If we have a file range that points to a compressed extent
2988		 * and it's followed by a consecutive file range that points to
2989		 * to the same compressed extent (possibly with a different
2990		 * offset and/or length, so it either points to the whole extent
2991		 * or only part of it), we must make sure we do not submit a
2992		 * single bio to populate the pages for the 2 ranges because
2993		 * this makes the compressed extent read zero out the pages
2994		 * belonging to the 2nd range. Imagine the following scenario:
2995		 *
2996		 *  File layout
2997		 *  [0 - 8K]                     [8K - 24K]
2998		 *    |                               |
2999		 *    |                               |
3000		 * points to extent X,         points to extent X,
3001		 * offset 4K, length of 8K     offset 0, length 16K
3002		 *
3003		 * [extent X, compressed length = 4K uncompressed length = 16K]
3004		 *
3005		 * If the bio to read the compressed extent covers both ranges,
3006		 * it will decompress extent X into the pages belonging to the
3007		 * first range and then it will stop, zeroing out the remaining
3008		 * pages that belong to the other range that points to extent X.
3009		 * So here we make sure we submit 2 bios, one for the first
3010		 * range and another one for the third range. Both will target
3011		 * the same physical extent from disk, but we can't currently
3012		 * make the compressed bio endio callback populate the pages
3013		 * for both ranges because each compressed bio is tightly
3014		 * coupled with a single extent map, and each range can have
3015		 * an extent map with a different offset value relative to the
3016		 * uncompressed data of our extent and different lengths. This
3017		 * is a corner case so we prioritize correctness over
3018		 * non-optimal behavior (submitting 2 bios for the same extent).
3019		 */
3020		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3021		    prev_em_start && *prev_em_start != (u64)-1 &&
3022		    *prev_em_start != em->orig_start)
3023			force_bio_submit = true;
3024
3025		if (prev_em_start)
3026			*prev_em_start = em->orig_start;
3027
3028		free_extent_map(em);
3029		em = NULL;
3030
3031		/* we've found a hole, just zero and go on */
3032		if (block_start == EXTENT_MAP_HOLE) {
3033			char *userpage;
3034			struct extent_state *cached = NULL;
3035
3036			userpage = kmap_atomic(page);
3037			memset(userpage + pg_offset, 0, iosize);
3038			flush_dcache_page(page);
3039			kunmap_atomic(userpage);
3040
3041			set_extent_uptodate(tree, cur, cur + iosize - 1,
3042					    &cached, GFP_NOFS);
3043			unlock_extent_cached(tree, cur,
3044					     cur + iosize - 1, &cached);
 
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		ret = submit_extent_page(REQ_OP_READ | read_flags, tree, NULL,
3070					 page, offset, disk_io_size,
3071					 pg_offset, bdev, bio,
3072					 end_bio_extent_readpage, mirror_num,
3073					 *bio_flags,
3074					 this_bio_flag,
3075					 force_bio_submit);
3076		if (!ret) {
3077			nr++;
3078			*bio_flags = this_bio_flag;
3079		} else {
3080			SetPageError(page);
3081			unlock_extent(tree, cur, cur + iosize - 1);
 
3082			goto out;
3083		}
3084		cur = cur + iosize;
3085		pg_offset += iosize;
3086	}
3087out:
3088	if (!nr) {
3089		if (!PageError(page))
3090			SetPageUptodate(page);
3091		unlock_page(page);
3092	}
3093	return ret;
3094}
3095
3096static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
3097					     struct page *pages[], int nr_pages,
3098					     u64 start, u64 end,
3099					     struct extent_map **em_cached,
3100					     struct bio **bio,
3101					     unsigned long *bio_flags,
3102					     u64 *prev_em_start)
3103{
3104	struct inode *inode;
3105	struct btrfs_ordered_extent *ordered;
3106	int index;
3107
3108	inode = pages[0]->mapping->host;
3109	while (1) {
3110		lock_extent(tree, start, end);
3111		ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
3112						     end - start + 1);
3113		if (!ordered)
3114			break;
3115		unlock_extent(tree, start, end);
3116		btrfs_start_ordered_extent(inode, ordered, 1);
3117		btrfs_put_ordered_extent(ordered);
3118	}
3119
3120	for (index = 0; index < nr_pages; index++) {
3121		__do_readpage(tree, pages[index], btrfs_get_extent, em_cached,
3122				bio, 0, bio_flags, 0, prev_em_start);
3123		put_page(pages[index]);
3124	}
3125}
3126
3127static void __extent_readpages(struct extent_io_tree *tree,
3128			       struct page *pages[],
3129			       int nr_pages,
3130			       struct extent_map **em_cached,
3131			       struct bio **bio, unsigned long *bio_flags,
3132			       u64 *prev_em_start)
3133{
3134	u64 start = 0;
3135	u64 end = 0;
3136	u64 page_start;
3137	int index;
3138	int first_index = 0;
3139
3140	for (index = 0; index < nr_pages; index++) {
3141		page_start = page_offset(pages[index]);
3142		if (!end) {
3143			start = page_start;
3144			end = start + PAGE_SIZE - 1;
3145			first_index = index;
3146		} else if (end + 1 == page_start) {
3147			end += PAGE_SIZE;
3148		} else {
3149			__do_contiguous_readpages(tree, &pages[first_index],
3150						  index - first_index, start,
3151						  end, em_cached,
3152						  bio, bio_flags,
3153						  prev_em_start);
3154			start = page_start;
3155			end = start + PAGE_SIZE - 1;
3156			first_index = index;
3157		}
3158	}
3159
3160	if (end)
3161		__do_contiguous_readpages(tree, &pages[first_index],
3162					  index - first_index, start,
3163					  end, em_cached, bio,
3164					  bio_flags, prev_em_start);
3165}
3166
3167static int __extent_read_full_page(struct extent_io_tree *tree,
3168				   struct page *page,
3169				   get_extent_t *get_extent,
3170				   struct bio **bio, int mirror_num,
3171				   unsigned long *bio_flags,
3172				   unsigned int read_flags)
3173{
3174	struct inode *inode = page->mapping->host;
3175	struct btrfs_ordered_extent *ordered;
3176	u64 start = page_offset(page);
3177	u64 end = start + PAGE_SIZE - 1;
3178	int ret;
3179
3180	while (1) {
3181		lock_extent(tree, start, end);
3182		ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
3183						PAGE_SIZE);
3184		if (!ordered)
3185			break;
3186		unlock_extent(tree, start, end);
3187		btrfs_start_ordered_extent(inode, ordered, 1);
3188		btrfs_put_ordered_extent(ordered);
3189	}
3190
3191	ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3192			    bio_flags, read_flags, NULL);
3193	return ret;
3194}
3195
3196int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3197			    get_extent_t *get_extent, int mirror_num)
3198{
3199	struct bio *bio = NULL;
3200	unsigned long bio_flags = 0;
3201	int ret;
3202
3203	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3204				      &bio_flags, 0);
3205	if (bio)
3206		ret = submit_one_bio(bio, mirror_num, bio_flags);
3207	return ret;
3208}
3209
3210static void update_nr_written(struct writeback_control *wbc,
3211			      unsigned long nr_written)
3212{
3213	wbc->nr_to_write -= nr_written;
3214}
3215
3216/*
3217 * helper for __extent_writepage, doing all of the delayed allocation setup.
3218 *
3219 * This returns 1 if our fill_delalloc function did all the work required
3220 * to write the page (copy into inline extent).  In this case the IO has
3221 * been started and the page is already unlocked.
3222 *
3223 * This returns 0 if all went well (page still locked)
3224 * This returns < 0 if there were errors (page still locked)
3225 */
3226static noinline_for_stack int writepage_delalloc(struct inode *inode,
3227			      struct page *page, struct writeback_control *wbc,
3228			      struct extent_page_data *epd,
3229			      u64 delalloc_start,
3230			      unsigned long *nr_written)
3231{
3232	struct extent_io_tree *tree = epd->tree;
3233	u64 page_end = delalloc_start + PAGE_SIZE - 1;
3234	u64 nr_delalloc;
3235	u64 delalloc_to_write = 0;
3236	u64 delalloc_end = 0;
3237	int ret;
3238	int page_started = 0;
3239
3240	if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
3241		return 0;
3242
3243	while (delalloc_end < page_end) {
3244		nr_delalloc = find_lock_delalloc_range(inode, tree,
3245					       page,
3246					       &delalloc_start,
3247					       &delalloc_end,
3248					       BTRFS_MAX_EXTENT_SIZE);
3249		if (nr_delalloc == 0) {
3250			delalloc_start = delalloc_end + 1;
3251			continue;
3252		}
3253		ret = tree->ops->fill_delalloc(inode, page,
3254					       delalloc_start,
3255					       delalloc_end,
3256					       &page_started,
3257					       nr_written, wbc);
3258		/* File system has been set read-only */
3259		if (ret) {
3260			SetPageError(page);
3261			/* fill_delalloc should be return < 0 for error
3262			 * but just in case, we use > 0 here meaning the
3263			 * IO is started, so we don't want to return > 0
3264			 * unless things are going well.
 
3265			 */
3266			ret = ret < 0 ? ret : -EIO;
3267			goto done;
3268		}
3269		/*
3270		 * delalloc_end is already one less than the total length, so
3271		 * we don't subtract one from PAGE_SIZE
3272		 */
3273		delalloc_to_write += (delalloc_end - delalloc_start +
3274				      PAGE_SIZE) >> PAGE_SHIFT;
3275		delalloc_start = delalloc_end + 1;
3276	}
3277	if (wbc->nr_to_write < delalloc_to_write) {
3278		int thresh = 8192;
3279
3280		if (delalloc_to_write < thresh * 2)
3281			thresh = delalloc_to_write;
3282		wbc->nr_to_write = min_t(u64, delalloc_to_write,
3283					 thresh);
3284	}
3285
3286	/* did the fill delalloc function already unlock and start
3287	 * the IO?
3288	 */
3289	if (page_started) {
3290		/*
3291		 * we've unlocked the page, so we can't update
3292		 * the mapping's writeback index, just update
3293		 * nr_to_write.
3294		 */
3295		wbc->nr_to_write -= *nr_written;
3296		return 1;
3297	}
3298
3299	ret = 0;
 
3300
3301done:
3302	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3303}
3304
3305/*
3306 * helper for __extent_writepage.  This calls the writepage start hooks,
3307 * and does the loop to map the page into extents and bios.
3308 *
3309 * We return 1 if the IO is started and the page is unlocked,
3310 * 0 if all went well (page still locked)
3311 * < 0 if there were errors (page still locked)
3312 */
3313static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3314				 struct page *page,
3315				 struct writeback_control *wbc,
3316				 struct extent_page_data *epd,
3317				 loff_t i_size,
3318				 unsigned long nr_written,
3319				 unsigned int write_flags, int *nr_ret)
3320{
3321	struct extent_io_tree *tree = epd->tree;
3322	u64 start = page_offset(page);
3323	u64 page_end = start + PAGE_SIZE - 1;
3324	u64 end;
3325	u64 cur = start;
3326	u64 extent_offset;
3327	u64 block_start;
3328	u64 iosize;
3329	struct extent_map *em;
3330	struct block_device *bdev;
3331	size_t pg_offset = 0;
3332	size_t blocksize;
3333	int ret = 0;
3334	int nr = 0;
 
 
3335	bool compressed;
3336
3337	if (tree->ops && tree->ops->writepage_start_hook) {
3338		ret = tree->ops->writepage_start_hook(page, start,
3339						      page_end);
3340		if (ret) {
3341			/* Fixup worker will requeue */
3342			if (ret == -EBUSY)
3343				wbc->pages_skipped++;
3344			else
3345				redirty_page_for_writepage(wbc, page);
3346
3347			update_nr_written(wbc, nr_written);
3348			unlock_page(page);
3349			return 1;
3350		}
3351	}
3352
3353	/*
3354	 * we don't want to touch the inode after unlocking the page,
3355	 * so we update the mapping writeback index now
3356	 */
3357	update_nr_written(wbc, nr_written + 1);
3358
3359	end = page_end;
3360	if (i_size <= start) {
3361		if (tree->ops && tree->ops->writepage_end_io_hook)
3362			tree->ops->writepage_end_io_hook(page, start,
3363							 page_end, NULL, 1);
3364		goto done;
3365	}
3366
3367	blocksize = inode->i_sb->s_blocksize;
3368
3369	while (cur <= end) {
 
3370		u64 em_end;
3371		u64 offset;
 
 
3372
3373		if (cur >= i_size) {
3374			if (tree->ops && tree->ops->writepage_end_io_hook)
3375				tree->ops->writepage_end_io_hook(page, cur,
3376							 page_end, NULL, 1);
3377			break;
3378		}
3379		em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, cur,
3380				     end - cur + 1, 1);
 
 
 
 
 
 
 
3381		if (IS_ERR_OR_NULL(em)) {
3382			SetPageError(page);
3383			ret = PTR_ERR_OR_ZERO(em);
3384			break;
3385		}
3386
3387		extent_offset = cur - em->start;
3388		em_end = extent_map_end(em);
3389		BUG_ON(em_end <= cur);
3390		BUG_ON(end < cur);
3391		iosize = min(em_end - cur, end - cur + 1);
3392		iosize = ALIGN(iosize, blocksize);
3393		offset = em->block_start + extent_offset;
3394		bdev = em->bdev;
3395		block_start = em->block_start;
3396		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 
 
 
 
 
 
 
 
 
 
 
3397		free_extent_map(em);
3398		em = NULL;
3399
3400		/*
3401		 * compressed and inline extents are written through other
3402		 * paths in the FS
3403		 */
3404		if (compressed || block_start == EXTENT_MAP_HOLE ||
3405		    block_start == EXTENT_MAP_INLINE) {
3406			/*
3407			 * end_io notification does not happen here for
3408			 * compressed extents
3409			 */
3410			if (!compressed && tree->ops &&
3411			    tree->ops->writepage_end_io_hook)
3412				tree->ops->writepage_end_io_hook(page, cur,
3413							 cur + iosize - 1,
3414							 NULL, 1);
3415			else if (compressed) {
3416				/* we don't want to end_page_writeback on
3417				 * a compressed extent.  this happens
3418				 * elsewhere
3419				 */
3420				nr++;
3421			}
3422
 
3423			cur += iosize;
3424			pg_offset += iosize;
3425			continue;
3426		}
3427
3428		set_range_writeback(tree, cur, cur + iosize - 1);
3429		if (!PageWriteback(page)) {
3430			btrfs_err(BTRFS_I(inode)->root->fs_info,
3431				   "page %lu not writeback, cur %llu end %llu",
3432			       page->index, cur, end);
3433		}
3434
3435		ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
3436					 page, offset, iosize, pg_offset,
3437					 bdev, &epd->bio,
 
 
 
 
 
 
 
 
 
3438					 end_bio_extent_writepage,
3439					 0, 0, 0, false);
3440		if (ret) {
3441			SetPageError(page);
3442			if (PageWriteback(page))
3443				end_page_writeback(page);
 
3444		}
3445
3446		cur = cur + iosize;
3447		pg_offset += iosize;
3448		nr++;
3449	}
3450done:
3451	*nr_ret = nr;
3452	return ret;
3453}
3454
3455/*
3456 * the writepage semantics are similar to regular writepage.  extent
3457 * records are inserted to lock ranges in the tree, and as dirty areas
3458 * are found, they are marked writeback.  Then the lock bits are removed
3459 * and the end_io handler clears the writeback ranges
 
 
 
3460 */
3461static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3462			      struct extent_page_data *epd)
3463{
3464	struct inode *inode = page->mapping->host;
3465	u64 start = page_offset(page);
3466	u64 page_end = start + PAGE_SIZE - 1;
3467	int ret;
3468	int nr = 0;
3469	size_t pg_offset = 0;
3470	loff_t i_size = i_size_read(inode);
3471	unsigned long end_index = i_size >> PAGE_SHIFT;
3472	unsigned int write_flags = 0;
3473	unsigned long nr_written = 0;
3474
3475	write_flags = wbc_to_write_flags(wbc);
3476
3477	trace___extent_writepage(page, inode, wbc);
3478
3479	WARN_ON(!PageLocked(page));
3480
3481	ClearPageError(page);
3482
3483	pg_offset = i_size & (PAGE_SIZE - 1);
3484	if (page->index > end_index ||
3485	   (page->index == end_index && !pg_offset)) {
3486		page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3487		unlock_page(page);
3488		return 0;
3489	}
3490
3491	if (page->index == end_index) {
3492		char *userpage;
3493
3494		userpage = kmap_atomic(page);
3495		memset(userpage + pg_offset, 0,
3496		       PAGE_SIZE - pg_offset);
3497		kunmap_atomic(userpage);
3498		flush_dcache_page(page);
3499	}
3500
3501	pg_offset = 0;
3502
3503	set_page_extent_mapped(page);
3504
3505	ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
3506	if (ret == 1)
3507		goto done_unlocked;
3508	if (ret)
3509		goto done;
 
3510
3511	ret = __extent_writepage_io(inode, page, wbc, epd,
3512				    i_size, nr_written, write_flags, &nr);
 
 
 
 
 
 
 
 
 
3513	if (ret == 1)
3514		goto done_unlocked;
3515
3516done:
3517	if (nr == 0) {
3518		/* make sure the mapping tag for page dirty gets cleared */
3519		set_page_writeback(page);
3520		end_page_writeback(page);
3521	}
3522	if (PageError(page)) {
3523		ret = ret < 0 ? ret : -EIO;
3524		end_extent_writepage(page, ret, start, page_end);
3525	}
3526	unlock_page(page);
 
3527	return ret;
3528
3529done_unlocked:
3530	return 0;
3531}
3532
3533void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3534{
3535	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3536		       TASK_UNINTERRUPTIBLE);
3537}
3538
3539static noinline_for_stack int
3540lock_extent_buffer_for_io(struct extent_buffer *eb,
3541			  struct btrfs_fs_info *fs_info,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3542			  struct extent_page_data *epd)
3543{
3544	unsigned long i, num_pages;
 
3545	int flush = 0;
3546	int ret = 0;
3547
3548	if (!btrfs_try_tree_write_lock(eb)) {
 
 
 
3549		flush = 1;
3550		flush_write_bio(epd);
3551		btrfs_tree_lock(eb);
3552	}
3553
3554	if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3555		btrfs_tree_unlock(eb);
3556		if (!epd->sync_io)
3557			return 0;
3558		if (!flush) {
3559			flush_write_bio(epd);
 
 
3560			flush = 1;
3561		}
3562		while (1) {
3563			wait_on_extent_buffer_writeback(eb);
3564			btrfs_tree_lock(eb);
3565			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3566				break;
3567			btrfs_tree_unlock(eb);
3568		}
3569	}
3570
3571	/*
3572	 * We need to do this to prevent races in people who check if the eb is
3573	 * under IO since we can end up having no IO bits set for a short period
3574	 * of time.
3575	 */
3576	spin_lock(&eb->refs_lock);
3577	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3578		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3579		spin_unlock(&eb->refs_lock);
3580		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3581		percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
3582					 -eb->len,
3583					 fs_info->dirty_metadata_batch);
3584		ret = 1;
3585	} else {
3586		spin_unlock(&eb->refs_lock);
3587	}
3588
3589	btrfs_tree_unlock(eb);
3590
3591	if (!ret)
 
 
 
 
 
 
3592		return ret;
3593
3594	num_pages = num_extent_pages(eb->start, eb->len);
3595	for (i = 0; i < num_pages; i++) {
3596		struct page *p = eb->pages[i];
3597
3598		if (!trylock_page(p)) {
3599			if (!flush) {
3600				flush_write_bio(epd);
 
 
 
 
 
 
 
3601				flush = 1;
3602			}
3603			lock_page(p);
3604		}
3605	}
3606
3607	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3608}
3609
3610static void end_extent_buffer_writeback(struct extent_buffer *eb)
3611{
3612	clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3613	smp_mb__after_atomic();
3614	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3615}
3616
3617static void set_btree_ioerr(struct page *page)
3618{
3619	struct extent_buffer *eb = (struct extent_buffer *)page->private;
3620
3621	SetPageError(page);
3622	if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3623		return;
3624
3625	/*
 
 
 
 
 
 
 
3626	 * If writeback for a btree extent that doesn't belong to a log tree
3627	 * failed, increment the counter transaction->eb_write_errors.
3628	 * We do this because while the transaction is running and before it's
3629	 * committing (when we call filemap_fdata[write|wait]_range against
3630	 * the btree inode), we might have
3631	 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3632	 * returns an error or an error happens during writeback, when we're
3633	 * committing the transaction we wouldn't know about it, since the pages
3634	 * can be no longer dirty nor marked anymore for writeback (if a
3635	 * subsequent modification to the extent buffer didn't happen before the
3636	 * transaction commit), which makes filemap_fdata[write|wait]_range not
3637	 * able to find the pages tagged with SetPageError at transaction
3638	 * commit time. So if this happens we must abort the transaction,
3639	 * otherwise we commit a super block with btree roots that point to
3640	 * btree nodes/leafs whose content on disk is invalid - either garbage
3641	 * or the content of some node/leaf from a past generation that got
3642	 * cowed or deleted and is no longer valid.
3643	 *
3644	 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3645	 * not be enough - we need to distinguish between log tree extents vs
3646	 * non-log tree extents, and the next filemap_fdatawait_range() call
3647	 * will catch and clear such errors in the mapping - and that call might
3648	 * be from a log sync and not from a transaction commit. Also, checking
3649	 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3650	 * not done and would not be reliable - the eb might have been released
3651	 * from memory and reading it back again means that flag would not be
3652	 * set (since it's a runtime flag, not persisted on disk).
3653	 *
3654	 * Using the flags below in the btree inode also makes us achieve the
3655	 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3656	 * writeback for all dirty pages and before filemap_fdatawait_range()
3657	 * is called, the writeback for all dirty pages had already finished
3658	 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3659	 * filemap_fdatawait_range() would return success, as it could not know
3660	 * that writeback errors happened (the pages were no longer tagged for
3661	 * writeback).
3662	 */
3663	switch (eb->log_index) {
3664	case -1:
3665		set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
3666		break;
3667	case 0:
3668		set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
3669		break;
3670	case 1:
3671		set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
3672		break;
3673	default:
3674		BUG(); /* unexpected, logic error */
3675	}
3676}
3677
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3678static void end_bio_extent_buffer_writepage(struct bio *bio)
3679{
3680	struct bio_vec *bvec;
3681	struct extent_buffer *eb;
3682	int i, done;
 
3683
3684	ASSERT(!bio_flagged(bio, BIO_CLONED));
3685	bio_for_each_segment_all(bvec, bio, i) {
3686		struct page *page = bvec->bv_page;
3687
3688		eb = (struct extent_buffer *)page->private;
3689		BUG_ON(!eb);
3690		done = atomic_dec_and_test(&eb->io_pages);
3691
3692		if (bio->bi_status ||
3693		    test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3694			ClearPageUptodate(page);
3695			set_btree_ioerr(page);
3696		}
3697
3698		end_page_writeback(page);
3699
3700		if (!done)
3701			continue;
3702
3703		end_extent_buffer_writeback(eb);
3704	}
3705
3706	bio_put(bio);
3707}
3708
3709static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3710			struct btrfs_fs_info *fs_info,
3711			struct writeback_control *wbc,
3712			struct extent_page_data *epd)
3713{
3714	struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3715	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3716	u64 offset = eb->start;
3717	u32 nritems;
3718	unsigned long i, num_pages;
3719	unsigned long start, end;
3720	unsigned int write_flags = wbc_to_write_flags(wbc) | REQ_META;
3721	int ret = 0;
3722
3723	clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3724	num_pages = num_extent_pages(eb->start, eb->len);
3725	atomic_set(&eb->io_pages, num_pages);
3726
3727	/* set btree blocks beyond nritems with 0 to avoid stale content. */
3728	nritems = btrfs_header_nritems(eb);
3729	if (btrfs_header_level(eb) > 0) {
3730		end = btrfs_node_key_ptr_offset(nritems);
3731
3732		memzero_extent_buffer(eb, end, eb->len - end);
3733	} else {
3734		/*
3735		 * leaf:
3736		 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
3737		 */
3738		start = btrfs_item_nr_offset(nritems);
3739		end = BTRFS_LEAF_DATA_OFFSET + leaf_data_end(fs_info, eb);
3740		memzero_extent_buffer(eb, start, end - start);
3741	}
 
3742
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3743	for (i = 0; i < num_pages; i++) {
3744		struct page *p = eb->pages[i];
3745
3746		clear_page_dirty_for_io(p);
3747		set_page_writeback(p);
3748		ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
3749					 p, offset, PAGE_SIZE, 0, bdev,
3750					 &epd->bio,
3751					 end_bio_extent_buffer_writepage,
3752					 0, 0, 0, false);
3753		if (ret) {
3754			set_btree_ioerr(p);
3755			if (PageWriteback(p))
3756				end_page_writeback(p);
3757			if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3758				end_extent_buffer_writeback(eb);
3759			ret = -EIO;
3760			break;
3761		}
3762		offset += PAGE_SIZE;
3763		update_nr_written(wbc, 1);
3764		unlock_page(p);
3765	}
3766
3767	if (unlikely(ret)) {
3768		for (; i < num_pages; i++) {
3769			struct page *p = eb->pages[i];
3770			clear_page_dirty_for_io(p);
3771			unlock_page(p);
3772		}
3773	}
3774
3775	return ret;
3776}
3777
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3778int btree_write_cache_pages(struct address_space *mapping,
3779				   struct writeback_control *wbc)
3780{
3781	struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3782	struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3783	struct extent_buffer *eb, *prev_eb = NULL;
3784	struct extent_page_data epd = {
3785		.bio = NULL,
3786		.tree = tree,
3787		.extent_locked = 0,
3788		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3789	};
 
3790	int ret = 0;
3791	int done = 0;
3792	int nr_to_write_done = 0;
3793	struct pagevec pvec;
3794	int nr_pages;
3795	pgoff_t index;
3796	pgoff_t end;		/* Inclusive */
3797	int scanned = 0;
3798	int tag;
3799
3800	pagevec_init(&pvec);
3801	if (wbc->range_cyclic) {
3802		index = mapping->writeback_index; /* Start from prev offset */
3803		end = -1;
 
 
 
 
 
3804	} else {
3805		index = wbc->range_start >> PAGE_SHIFT;
3806		end = wbc->range_end >> PAGE_SHIFT;
3807		scanned = 1;
3808	}
3809	if (wbc->sync_mode == WB_SYNC_ALL)
3810		tag = PAGECACHE_TAG_TOWRITE;
3811	else
3812		tag = PAGECACHE_TAG_DIRTY;
 
3813retry:
3814	if (wbc->sync_mode == WB_SYNC_ALL)
3815		tag_pages_for_writeback(mapping, index, end);
3816	while (!done && !nr_to_write_done && (index <= end) &&
3817	       (nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
3818			tag))) {
3819		unsigned i;
3820
3821		scanned = 1;
3822		for (i = 0; i < nr_pages; i++) {
3823			struct page *page = pvec.pages[i];
3824
3825			if (!PagePrivate(page))
3826				continue;
3827
3828			spin_lock(&mapping->private_lock);
3829			if (!PagePrivate(page)) {
3830				spin_unlock(&mapping->private_lock);
3831				continue;
3832			}
3833
3834			eb = (struct extent_buffer *)page->private;
3835
3836			/*
3837			 * Shouldn't happen and normally this would be a BUG_ON
3838			 * but no sense in crashing the users box for something
3839			 * we can survive anyway.
3840			 */
3841			if (WARN_ON(!eb)) {
3842				spin_unlock(&mapping->private_lock);
3843				continue;
3844			}
3845
3846			if (eb == prev_eb) {
3847				spin_unlock(&mapping->private_lock);
3848				continue;
3849			}
3850
3851			ret = atomic_inc_not_zero(&eb->refs);
3852			spin_unlock(&mapping->private_lock);
3853			if (!ret)
3854				continue;
3855
3856			prev_eb = eb;
3857			ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3858			if (!ret) {
3859				free_extent_buffer(eb);
3860				continue;
3861			}
3862
3863			ret = write_one_eb(eb, fs_info, wbc, &epd);
3864			if (ret) {
3865				done = 1;
3866				free_extent_buffer(eb);
3867				break;
3868			}
3869			free_extent_buffer(eb);
3870
3871			/*
3872			 * the filesystem may choose to bump up nr_to_write.
3873			 * We have to make sure to honor the new nr_to_write
3874			 * at any time
3875			 */
3876			nr_to_write_done = wbc->nr_to_write <= 0;
3877		}
3878		pagevec_release(&pvec);
3879		cond_resched();
3880	}
3881	if (!scanned && !done) {
3882		/*
3883		 * We hit the last page and there is more work to be done: wrap
3884		 * back to the start of the file
3885		 */
3886		scanned = 1;
3887		index = 0;
3888		goto retry;
3889	}
3890	flush_write_bio(&epd);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3891	return ret;
3892}
3893
3894/**
3895 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
 
3896 * @mapping: address space structure to write
3897 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3898 * @data: data passed to __extent_writepage function
3899 *
3900 * If a page is already under I/O, write_cache_pages() skips it, even
3901 * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
3902 * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
3903 * and msync() need to guarantee that all the data which was dirty at the time
3904 * the call was made get new I/O started against them.  If wbc->sync_mode is
3905 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3906 * existing IO to complete.
3907 */
3908static int extent_write_cache_pages(struct address_space *mapping,
3909			     struct writeback_control *wbc,
3910			     struct extent_page_data *epd)
3911{
3912	struct inode *inode = mapping->host;
3913	int ret = 0;
3914	int done = 0;
3915	int nr_to_write_done = 0;
3916	struct pagevec pvec;
3917	int nr_pages;
3918	pgoff_t index;
3919	pgoff_t end;		/* Inclusive */
3920	pgoff_t done_index;
3921	int range_whole = 0;
3922	int scanned = 0;
3923	int tag;
3924
3925	/*
3926	 * We have to hold onto the inode so that ordered extents can do their
3927	 * work when the IO finishes.  The alternative to this is failing to add
3928	 * an ordered extent if the igrab() fails there and that is a huge pain
3929	 * to deal with, so instead just hold onto the inode throughout the
3930	 * writepages operation.  If it fails here we are freeing up the inode
3931	 * anyway and we'd rather not waste our time writing out stuff that is
3932	 * going to be truncated anyway.
3933	 */
3934	if (!igrab(inode))
3935		return 0;
3936
3937	pagevec_init(&pvec);
3938	if (wbc->range_cyclic) {
3939		index = mapping->writeback_index; /* Start from prev offset */
3940		end = -1;
 
 
 
 
 
3941	} else {
3942		index = wbc->range_start >> PAGE_SHIFT;
3943		end = wbc->range_end >> PAGE_SHIFT;
3944		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
3945			range_whole = 1;
3946		scanned = 1;
3947	}
3948	if (wbc->sync_mode == WB_SYNC_ALL)
 
 
 
 
 
 
 
 
 
 
 
 
 
3949		tag = PAGECACHE_TAG_TOWRITE;
3950	else
3951		tag = PAGECACHE_TAG_DIRTY;
3952retry:
3953	if (wbc->sync_mode == WB_SYNC_ALL)
3954		tag_pages_for_writeback(mapping, index, end);
3955	done_index = index;
3956	while (!done && !nr_to_write_done && (index <= end) &&
3957			(nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
3958						&index, end, tag))) {
3959		unsigned i;
3960
3961		scanned = 1;
3962		for (i = 0; i < nr_pages; i++) {
3963			struct page *page = pvec.pages[i];
3964
3965			done_index = page->index;
3966			/*
3967			 * At this point we hold neither the i_pages lock nor
3968			 * the page lock: the page may be truncated or
3969			 * invalidated (changing page->mapping to NULL),
3970			 * or even swizzled back from swapper_space to
3971			 * tmpfs file mapping
3972			 */
3973			if (!trylock_page(page)) {
3974				flush_write_bio(epd);
 
3975				lock_page(page);
3976			}
3977
3978			if (unlikely(page->mapping != mapping)) {
3979				unlock_page(page);
3980				continue;
3981			}
3982
3983			if (wbc->sync_mode != WB_SYNC_NONE) {
3984				if (PageWriteback(page))
3985					flush_write_bio(epd);
 
 
3986				wait_on_page_writeback(page);
3987			}
3988
3989			if (PageWriteback(page) ||
3990			    !clear_page_dirty_for_io(page)) {
3991				unlock_page(page);
3992				continue;
3993			}
3994
3995			ret = __extent_writepage(page, wbc, epd);
3996
3997			if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
3998				unlock_page(page);
3999				ret = 0;
4000			}
4001			if (ret < 0) {
4002				/*
4003				 * done_index is set past this page,
4004				 * so media errors will not choke
4005				 * background writeout for the entire
4006				 * file. This has consequences for
4007				 * range_cyclic semantics (ie. it may
4008				 * not be suitable for data integrity
4009				 * writeout).
4010				 */
4011				done_index = page->index + 1;
4012				done = 1;
4013				break;
4014			}
4015
4016			/*
4017			 * the filesystem may choose to bump up nr_to_write.
4018			 * We have to make sure to honor the new nr_to_write
4019			 * at any time
4020			 */
4021			nr_to_write_done = wbc->nr_to_write <= 0;
4022		}
4023		pagevec_release(&pvec);
4024		cond_resched();
4025	}
4026	if (!scanned && !done) {
4027		/*
4028		 * We hit the last page and there is more work to be done: wrap
4029		 * back to the start of the file
4030		 */
4031		scanned = 1;
4032		index = 0;
4033		goto retry;
 
 
 
 
 
 
 
 
 
4034	}
4035
4036	if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
4037		mapping->writeback_index = done_index;
4038
4039	btrfs_add_delayed_iput(inode);
4040	return ret;
4041}
4042
4043static void flush_write_bio(struct extent_page_data *epd)
4044{
4045	if (epd->bio) {
4046		int ret;
4047
4048		ret = submit_one_bio(epd->bio, 0, 0);
4049		BUG_ON(ret < 0); /* -ENOMEM */
4050		epd->bio = NULL;
4051	}
4052}
4053
4054int extent_write_full_page(struct page *page, struct writeback_control *wbc)
4055{
4056	int ret;
4057	struct extent_page_data epd = {
4058		.bio = NULL,
4059		.tree = &BTRFS_I(page->mapping->host)->io_tree,
4060		.extent_locked = 0,
4061		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4062	};
4063
4064	ret = __extent_writepage(page, wbc, &epd);
 
 
 
 
 
4065
4066	flush_write_bio(&epd);
 
4067	return ret;
4068}
4069
4070int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
4071			      int mode)
4072{
4073	int ret = 0;
4074	struct address_space *mapping = inode->i_mapping;
4075	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
4076	struct page *page;
4077	unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4078		PAGE_SHIFT;
4079
4080	struct extent_page_data epd = {
4081		.bio = NULL,
4082		.tree = tree,
4083		.extent_locked = 1,
4084		.sync_io = mode == WB_SYNC_ALL,
4085	};
4086	struct writeback_control wbc_writepages = {
4087		.sync_mode	= mode,
4088		.nr_to_write	= nr_pages * 2,
4089		.range_start	= start,
4090		.range_end	= end + 1,
 
 
 
4091	};
4092
 
4093	while (start <= end) {
4094		page = find_get_page(mapping, start >> PAGE_SHIFT);
4095		if (clear_page_dirty_for_io(page))
4096			ret = __extent_writepage(page, &wbc_writepages, &epd);
4097		else {
4098			if (tree->ops && tree->ops->writepage_end_io_hook)
4099				tree->ops->writepage_end_io_hook(page, start,
4100						 start + PAGE_SIZE - 1,
4101						 NULL, 1);
4102			unlock_page(page);
4103		}
4104		put_page(page);
4105		start += PAGE_SIZE;
4106	}
4107
4108	flush_write_bio(&epd);
 
 
 
 
 
 
4109	return ret;
4110}
4111
4112int extent_writepages(struct extent_io_tree *tree,
4113		      struct address_space *mapping,
4114		      struct writeback_control *wbc)
4115{
4116	int ret = 0;
4117	struct extent_page_data epd = {
4118		.bio = NULL,
4119		.tree = tree,
4120		.extent_locked = 0,
4121		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4122	};
4123
4124	ret = extent_write_cache_pages(mapping, wbc, &epd);
4125	flush_write_bio(&epd);
 
 
 
 
 
4126	return ret;
4127}
4128
4129int extent_readpages(struct extent_io_tree *tree,
4130		     struct address_space *mapping,
4131		     struct list_head *pages, unsigned nr_pages)
4132{
4133	struct bio *bio = NULL;
4134	unsigned page_idx;
4135	unsigned long bio_flags = 0;
4136	struct page *pagepool[16];
4137	struct page *page;
4138	struct extent_map *em_cached = NULL;
4139	int nr = 0;
4140	u64 prev_em_start = (u64)-1;
 
4141
4142	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
4143		page = list_entry(pages->prev, struct page, lru);
 
4144
4145		prefetchw(&page->flags);
4146		list_del(&page->lru);
4147		if (add_to_page_cache_lru(page, mapping,
4148					page->index,
4149					readahead_gfp_mask(mapping))) {
4150			put_page(page);
4151			continue;
4152		}
4153
4154		pagepool[nr++] = page;
4155		if (nr < ARRAY_SIZE(pagepool))
4156			continue;
4157		__extent_readpages(tree, pagepool, nr, &em_cached, &bio,
4158				&bio_flags, &prev_em_start);
4159		nr = 0;
4160	}
4161	if (nr)
4162		__extent_readpages(tree, pagepool, nr, &em_cached, &bio,
4163				&bio_flags, &prev_em_start);
4164
4165	if (em_cached)
4166		free_extent_map(em_cached);
4167
4168	BUG_ON(!list_empty(pages));
4169	if (bio)
4170		return submit_one_bio(bio, 0, bio_flags);
4171	return 0;
4172}
4173
4174/*
4175 * basic invalidatepage code, this waits on any locked or writeback
4176 * ranges corresponding to the page, and then deletes any extent state
4177 * records from the tree
4178 */
4179int extent_invalidatepage(struct extent_io_tree *tree,
4180			  struct page *page, unsigned long offset)
4181{
4182	struct extent_state *cached_state = NULL;
4183	u64 start = page_offset(page);
4184	u64 end = start + PAGE_SIZE - 1;
4185	size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4186
 
 
 
4187	start += ALIGN(offset, blocksize);
4188	if (start > end)
4189		return 0;
4190
4191	lock_extent_bits(tree, start, end, &cached_state);
4192	wait_on_page_writeback(page);
4193	clear_extent_bit(tree, start, end,
4194			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4195			 EXTENT_DO_ACCOUNTING,
4196			 1, 1, &cached_state);
 
 
 
4197	return 0;
4198}
4199
4200/*
4201 * a helper for releasepage, this tests for areas of the page that
4202 * are locked or under IO and drops the related state bits if it is safe
4203 * to drop the page.
4204 */
4205static int try_release_extent_state(struct extent_map_tree *map,
4206				    struct extent_io_tree *tree,
4207				    struct page *page, gfp_t mask)
4208{
4209	u64 start = page_offset(page);
4210	u64 end = start + PAGE_SIZE - 1;
4211	int ret = 1;
4212
4213	if (test_range_bit(tree, start, end,
4214			   EXTENT_IOBITS, 0, NULL))
4215		ret = 0;
4216	else {
4217		/*
4218		 * at this point we can safely clear everything except the
4219		 * locked bit and the nodatasum bit
 
 
4220		 */
4221		ret = __clear_extent_bit(tree, start, end,
4222				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4223				 0, 0, NULL, mask, NULL);
4224
4225		/* if clear_extent_bit failed for enomem reasons,
4226		 * we can't allow the release to continue.
4227		 */
4228		if (ret < 0)
4229			ret = 0;
4230		else
4231			ret = 1;
4232	}
4233	return ret;
4234}
4235
4236/*
4237 * a helper for releasepage.  As long as there are no locked extents
4238 * in the range corresponding to the page, both state records and extent
4239 * map records are removed
4240 */
4241int try_release_extent_mapping(struct extent_map_tree *map,
4242			       struct extent_io_tree *tree, struct page *page,
4243			       gfp_t mask)
4244{
4245	struct extent_map *em;
4246	u64 start = page_offset(page);
4247	u64 end = start + PAGE_SIZE - 1;
 
 
 
4248
4249	if (gfpflags_allow_blocking(mask) &&
4250	    page->mapping->host->i_size > SZ_16M) {
4251		u64 len;
4252		while (start <= end) {
 
 
 
4253			len = end - start + 1;
4254			write_lock(&map->lock);
4255			em = lookup_extent_mapping(map, start, len);
4256			if (!em) {
4257				write_unlock(&map->lock);
4258				break;
4259			}
4260			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4261			    em->start != start) {
4262				write_unlock(&map->lock);
4263				free_extent_map(em);
4264				break;
4265			}
4266			if (!test_range_bit(tree, em->start,
4267					    extent_map_end(em) - 1,
4268					    EXTENT_LOCKED | EXTENT_WRITEBACK,
4269					    0, NULL)) {
4270				remove_extent_mapping(map, em);
4271				/* once for the rb tree */
4272				free_extent_map(em);
4273			}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4274			start = extent_map_end(em);
4275			write_unlock(&map->lock);
4276
4277			/* once for us */
4278			free_extent_map(em);
 
 
4279		}
4280	}
4281	return try_release_extent_state(map, tree, page, mask);
4282}
4283
4284/*
4285 * helper function for fiemap, which doesn't want to see any holes.
4286 * This maps until we find something past 'last'
4287 */
4288static struct extent_map *get_extent_skip_holes(struct inode *inode,
4289						u64 offset, u64 last)
4290{
4291	u64 sectorsize = btrfs_inode_sectorsize(inode);
4292	struct extent_map *em;
4293	u64 len;
4294
4295	if (offset >= last)
4296		return NULL;
4297
4298	while (1) {
4299		len = last - offset;
4300		if (len == 0)
4301			break;
4302		len = ALIGN(len, sectorsize);
4303		em = btrfs_get_extent_fiemap(BTRFS_I(inode), NULL, 0, offset,
4304				len, 0);
4305		if (IS_ERR_OR_NULL(em))
4306			return em;
4307
4308		/* if this isn't a hole return it */
4309		if (em->block_start != EXTENT_MAP_HOLE)
4310			return em;
4311
4312		/* this is a hole, advance to the next extent */
4313		offset = extent_map_end(em);
4314		free_extent_map(em);
4315		if (offset >= last)
4316			break;
4317	}
4318	return NULL;
4319}
4320
4321/*
4322 * To cache previous fiemap extent
4323 *
4324 * Will be used for merging fiemap extent
4325 */
4326struct fiemap_cache {
4327	u64 offset;
4328	u64 phys;
4329	u64 len;
4330	u32 flags;
4331	bool cached;
4332};
4333
4334/*
4335 * Helper to submit fiemap extent.
4336 *
4337 * Will try to merge current fiemap extent specified by @offset, @phys,
4338 * @len and @flags with cached one.
4339 * And only when we fails to merge, cached one will be submitted as
4340 * fiemap extent.
4341 *
4342 * Return value is the same as fiemap_fill_next_extent().
4343 */
4344static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
4345				struct fiemap_cache *cache,
4346				u64 offset, u64 phys, u64 len, u32 flags)
4347{
4348	int ret = 0;
4349
4350	if (!cache->cached)
4351		goto assign;
4352
4353	/*
4354	 * Sanity check, extent_fiemap() should have ensured that new
4355	 * fiemap extent won't overlap with cahced one.
4356	 * Not recoverable.
4357	 *
4358	 * NOTE: Physical address can overlap, due to compression
4359	 */
4360	if (cache->offset + cache->len > offset) {
4361		WARN_ON(1);
4362		return -EINVAL;
4363	}
4364
4365	/*
4366	 * Only merges fiemap extents if
4367	 * 1) Their logical addresses are continuous
4368	 *
4369	 * 2) Their physical addresses are continuous
4370	 *    So truly compressed (physical size smaller than logical size)
4371	 *    extents won't get merged with each other
4372	 *
4373	 * 3) Share same flags except FIEMAP_EXTENT_LAST
4374	 *    So regular extent won't get merged with prealloc extent
4375	 */
4376	if (cache->offset + cache->len  == offset &&
4377	    cache->phys + cache->len == phys  &&
4378	    (cache->flags & ~FIEMAP_EXTENT_LAST) ==
4379			(flags & ~FIEMAP_EXTENT_LAST)) {
4380		cache->len += len;
4381		cache->flags |= flags;
4382		goto try_submit_last;
4383	}
4384
4385	/* Not mergeable, need to submit cached one */
4386	ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
4387				      cache->len, cache->flags);
4388	cache->cached = false;
4389	if (ret)
4390		return ret;
4391assign:
4392	cache->cached = true;
4393	cache->offset = offset;
4394	cache->phys = phys;
4395	cache->len = len;
4396	cache->flags = flags;
4397try_submit_last:
4398	if (cache->flags & FIEMAP_EXTENT_LAST) {
4399		ret = fiemap_fill_next_extent(fieinfo, cache->offset,
4400				cache->phys, cache->len, cache->flags);
4401		cache->cached = false;
4402	}
4403	return ret;
4404}
4405
4406/*
4407 * Emit last fiemap cache
4408 *
4409 * The last fiemap cache may still be cached in the following case:
4410 * 0		      4k		    8k
4411 * |<- Fiemap range ->|
4412 * |<------------  First extent ----------->|
4413 *
4414 * In this case, the first extent range will be cached but not emitted.
4415 * So we must emit it before ending extent_fiemap().
4416 */
4417static int emit_last_fiemap_cache(struct btrfs_fs_info *fs_info,
4418				  struct fiemap_extent_info *fieinfo,
4419				  struct fiemap_cache *cache)
4420{
4421	int ret;
4422
4423	if (!cache->cached)
4424		return 0;
4425
4426	ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
4427				      cache->len, cache->flags);
4428	cache->cached = false;
4429	if (ret > 0)
4430		ret = 0;
4431	return ret;
4432}
4433
4434int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4435		__u64 start, __u64 len)
4436{
4437	int ret = 0;
4438	u64 off = start;
4439	u64 max = start + len;
4440	u32 flags = 0;
4441	u32 found_type;
4442	u64 last;
4443	u64 last_for_get_extent = 0;
4444	u64 disko = 0;
4445	u64 isize = i_size_read(inode);
4446	struct btrfs_key found_key;
4447	struct extent_map *em = NULL;
4448	struct extent_state *cached_state = NULL;
4449	struct btrfs_path *path;
4450	struct btrfs_root *root = BTRFS_I(inode)->root;
4451	struct fiemap_cache cache = { 0 };
 
 
4452	int end = 0;
4453	u64 em_start = 0;
4454	u64 em_len = 0;
4455	u64 em_end = 0;
4456
4457	if (len == 0)
4458		return -EINVAL;
4459
4460	path = btrfs_alloc_path();
4461	if (!path)
4462		return -ENOMEM;
4463	path->leave_spinning = 1;
4464
 
 
 
 
 
 
 
 
 
 
 
 
4465	start = round_down(start, btrfs_inode_sectorsize(inode));
4466	len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
4467
4468	/*
4469	 * lookup the last file extent.  We're not using i_size here
4470	 * because there might be preallocation past i_size
4471	 */
4472	ret = btrfs_lookup_file_extent(NULL, root, path,
4473			btrfs_ino(BTRFS_I(inode)), -1, 0);
4474	if (ret < 0) {
4475		btrfs_free_path(path);
4476		return ret;
4477	} else {
4478		WARN_ON(!ret);
4479		if (ret == 1)
4480			ret = 0;
4481	}
4482
4483	path->slots[0]--;
4484	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4485	found_type = found_key.type;
4486
4487	/* No extents, but there might be delalloc bits */
4488	if (found_key.objectid != btrfs_ino(BTRFS_I(inode)) ||
4489	    found_type != BTRFS_EXTENT_DATA_KEY) {
4490		/* have to trust i_size as the end */
4491		last = (u64)-1;
4492		last_for_get_extent = isize;
4493	} else {
4494		/*
4495		 * remember the start of the last extent.  There are a
4496		 * bunch of different factors that go into the length of the
4497		 * extent, so its much less complex to remember where it started
4498		 */
4499		last = found_key.offset;
4500		last_for_get_extent = last + 1;
4501	}
4502	btrfs_release_path(path);
4503
4504	/*
4505	 * we might have some extents allocated but more delalloc past those
4506	 * extents.  so, we trust isize unless the start of the last extent is
4507	 * beyond isize
4508	 */
4509	if (last < isize) {
4510		last = (u64)-1;
4511		last_for_get_extent = isize;
4512	}
4513
4514	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4515			 &cached_state);
4516
4517	em = get_extent_skip_holes(inode, start, last_for_get_extent);
4518	if (!em)
4519		goto out;
4520	if (IS_ERR(em)) {
4521		ret = PTR_ERR(em);
4522		goto out;
4523	}
4524
4525	while (!end) {
4526		u64 offset_in_extent = 0;
4527
4528		/* break if the extent we found is outside the range */
4529		if (em->start >= max || extent_map_end(em) < off)
4530			break;
4531
4532		/*
4533		 * get_extent may return an extent that starts before our
4534		 * requested range.  We have to make sure the ranges
4535		 * we return to fiemap always move forward and don't
4536		 * overlap, so adjust the offsets here
4537		 */
4538		em_start = max(em->start, off);
4539
4540		/*
4541		 * record the offset from the start of the extent
4542		 * for adjusting the disk offset below.  Only do this if the
4543		 * extent isn't compressed since our in ram offset may be past
4544		 * what we have actually allocated on disk.
4545		 */
4546		if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4547			offset_in_extent = em_start - em->start;
4548		em_end = extent_map_end(em);
4549		em_len = em_end - em_start;
4550		disko = 0;
4551		flags = 0;
 
 
 
 
4552
4553		/*
4554		 * bump off for our next call to get_extent
4555		 */
4556		off = extent_map_end(em);
4557		if (off >= max)
4558			end = 1;
4559
4560		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4561			end = 1;
4562			flags |= FIEMAP_EXTENT_LAST;
4563		} else if (em->block_start == EXTENT_MAP_INLINE) {
4564			flags |= (FIEMAP_EXTENT_DATA_INLINE |
4565				  FIEMAP_EXTENT_NOT_ALIGNED);
4566		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
4567			flags |= (FIEMAP_EXTENT_DELALLOC |
4568				  FIEMAP_EXTENT_UNKNOWN);
4569		} else if (fieinfo->fi_extents_max) {
4570			u64 bytenr = em->block_start -
4571				(em->start - em->orig_start);
4572
4573			disko = em->block_start + offset_in_extent;
4574
4575			/*
4576			 * As btrfs supports shared space, this information
4577			 * can be exported to userspace tools via
4578			 * flag FIEMAP_EXTENT_SHARED.  If fi_extents_max == 0
4579			 * then we're just getting a count and we can skip the
4580			 * lookup stuff.
4581			 */
4582			ret = btrfs_check_shared(root,
4583						 btrfs_ino(BTRFS_I(inode)),
4584						 bytenr);
4585			if (ret < 0)
4586				goto out_free;
4587			if (ret)
4588				flags |= FIEMAP_EXTENT_SHARED;
4589			ret = 0;
4590		}
4591		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4592			flags |= FIEMAP_EXTENT_ENCODED;
4593		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4594			flags |= FIEMAP_EXTENT_UNWRITTEN;
4595
4596		free_extent_map(em);
4597		em = NULL;
4598		if ((em_start >= last) || em_len == (u64)-1 ||
4599		   (last == (u64)-1 && isize <= em_end)) {
4600			flags |= FIEMAP_EXTENT_LAST;
4601			end = 1;
4602		}
4603
4604		/* now scan forward to see if this is really the last extent. */
4605		em = get_extent_skip_holes(inode, off, last_for_get_extent);
4606		if (IS_ERR(em)) {
4607			ret = PTR_ERR(em);
4608			goto out;
4609		}
4610		if (!em) {
4611			flags |= FIEMAP_EXTENT_LAST;
4612			end = 1;
4613		}
4614		ret = emit_fiemap_extent(fieinfo, &cache, em_start, disko,
4615					   em_len, flags);
4616		if (ret) {
4617			if (ret == 1)
4618				ret = 0;
4619			goto out_free;
4620		}
4621	}
4622out_free:
4623	if (!ret)
4624		ret = emit_last_fiemap_cache(root->fs_info, fieinfo, &cache);
4625	free_extent_map(em);
4626out:
4627	btrfs_free_path(path);
4628	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4629			     &cached_state);
 
 
 
 
 
4630	return ret;
4631}
4632
4633static void __free_extent_buffer(struct extent_buffer *eb)
4634{
4635	btrfs_leak_debug_del(&eb->leak_list);
4636	kmem_cache_free(extent_buffer_cache, eb);
4637}
4638
4639int extent_buffer_under_io(struct extent_buffer *eb)
4640{
4641	return (atomic_read(&eb->io_pages) ||
4642		test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4643		test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4644}
4645
4646/*
4647 * Helper for releasing extent buffer page.
4648 */
4649static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4650{
4651	unsigned long index;
4652	struct page *page;
4653	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4654
4655	BUG_ON(extent_buffer_under_io(eb));
4656
4657	index = num_extent_pages(eb->start, eb->len);
4658	if (index == 0)
4659		return;
 
 
 
 
 
 
 
 
 
 
4660
4661	do {
4662		index--;
4663		page = eb->pages[index];
4664		if (!page)
4665			continue;
 
 
 
 
 
 
 
 
4666		if (mapped)
4667			spin_lock(&page->mapping->private_lock);
 
 
 
 
4668		/*
4669		 * We do this since we'll remove the pages after we've
4670		 * removed the eb from the radix tree, so we could race
4671		 * and have this page now attached to the new eb.  So
4672		 * only clear page_private if it's still connected to
4673		 * this eb.
4674		 */
4675		if (PagePrivate(page) &&
4676		    page->private == (unsigned long)eb) {
4677			BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4678			BUG_ON(PageDirty(page));
4679			BUG_ON(PageWriteback(page));
4680			/*
4681			 * We need to make sure we haven't be attached
4682			 * to a new eb.
4683			 */
4684			ClearPagePrivate(page);
4685			set_page_private(page, 0);
4686			/* One for the page private */
4687			put_page(page);
4688		}
4689
4690		if (mapped)
4691			spin_unlock(&page->mapping->private_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4692
4693		/* One for when we allocated the page */
4694		put_page(page);
4695	} while (index != 0);
4696}
4697
4698/*
4699 * Helper for releasing the extent buffer.
4700 */
4701static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4702{
4703	btrfs_release_extent_buffer_page(eb);
 
4704	__free_extent_buffer(eb);
4705}
4706
4707static struct extent_buffer *
4708__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4709		      unsigned long len)
4710{
4711	struct extent_buffer *eb = NULL;
4712
4713	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4714	eb->start = start;
4715	eb->len = len;
4716	eb->fs_info = fs_info;
4717	eb->bflags = 0;
4718	rwlock_init(&eb->lock);
4719	atomic_set(&eb->write_locks, 0);
4720	atomic_set(&eb->read_locks, 0);
4721	atomic_set(&eb->blocking_readers, 0);
4722	atomic_set(&eb->blocking_writers, 0);
4723	atomic_set(&eb->spinning_readers, 0);
4724	atomic_set(&eb->spinning_writers, 0);
4725	eb->lock_nested = 0;
4726	init_waitqueue_head(&eb->write_lock_wq);
4727	init_waitqueue_head(&eb->read_lock_wq);
4728
4729	btrfs_leak_debug_add(&eb->leak_list, &buffers);
 
 
4730
4731	spin_lock_init(&eb->refs_lock);
4732	atomic_set(&eb->refs, 1);
4733	atomic_set(&eb->io_pages, 0);
4734
4735	/*
4736	 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4737	 */
4738	BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4739		> MAX_INLINE_EXTENT_BUFFER_SIZE);
4740	BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4741
4742	return eb;
4743}
4744
4745struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4746{
4747	unsigned long i;
4748	struct page *p;
4749	struct extent_buffer *new;
4750	unsigned long num_pages = num_extent_pages(src->start, src->len);
4751
4752	new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4753	if (new == NULL)
4754		return NULL;
4755
 
 
 
 
 
 
 
4756	for (i = 0; i < num_pages; i++) {
 
 
4757		p = alloc_page(GFP_NOFS);
4758		if (!p) {
4759			btrfs_release_extent_buffer(new);
4760			return NULL;
4761		}
4762		attach_extent_buffer_page(new, p);
 
 
 
 
 
4763		WARN_ON(PageDirty(p));
4764		SetPageUptodate(p);
4765		new->pages[i] = p;
4766		copy_page(page_address(p), page_address(src->pages[i]));
4767	}
4768
4769	set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4770	set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
4771
4772	return new;
4773}
4774
4775struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4776						  u64 start, unsigned long len)
4777{
4778	struct extent_buffer *eb;
4779	unsigned long num_pages;
4780	unsigned long i;
4781
4782	num_pages = num_extent_pages(start, len);
4783
4784	eb = __alloc_extent_buffer(fs_info, start, len);
4785	if (!eb)
4786		return NULL;
4787
 
4788	for (i = 0; i < num_pages; i++) {
 
 
4789		eb->pages[i] = alloc_page(GFP_NOFS);
4790		if (!eb->pages[i])
4791			goto err;
 
 
 
4792	}
4793	set_extent_buffer_uptodate(eb);
4794	btrfs_set_header_nritems(eb, 0);
4795	set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4796
4797	return eb;
4798err:
4799	for (; i > 0; i--)
 
4800		__free_page(eb->pages[i - 1]);
 
4801	__free_extent_buffer(eb);
4802	return NULL;
4803}
4804
4805struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4806						u64 start)
4807{
4808	return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
4809}
4810
4811static void check_buffer_tree_ref(struct extent_buffer *eb)
4812{
4813	int refs;
4814	/* the ref bit is tricky.  We have to make sure it is set
4815	 * if we have the buffer dirty.   Otherwise the
4816	 * code to free a buffer can end up dropping a dirty
4817	 * page
4818	 *
4819	 * Once the ref bit is set, it won't go away while the
4820	 * buffer is dirty or in writeback, and it also won't
4821	 * go away while we have the reference count on the
4822	 * eb bumped.
4823	 *
4824	 * We can't just set the ref bit without bumping the
4825	 * ref on the eb because free_extent_buffer might
4826	 * see the ref bit and try to clear it.  If this happens
4827	 * free_extent_buffer might end up dropping our original
4828	 * ref by mistake and freeing the page before we are able
4829	 * to add one more ref.
4830	 *
4831	 * So bump the ref count first, then set the bit.  If someone
4832	 * beat us to it, drop the ref we added.
 
 
 
 
 
4833	 */
4834	refs = atomic_read(&eb->refs);
4835	if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4836		return;
4837
4838	spin_lock(&eb->refs_lock);
4839	if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4840		atomic_inc(&eb->refs);
4841	spin_unlock(&eb->refs_lock);
4842}
4843
4844static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4845		struct page *accessed)
4846{
4847	unsigned long num_pages, i;
4848
4849	check_buffer_tree_ref(eb);
4850
4851	num_pages = num_extent_pages(eb->start, eb->len);
4852	for (i = 0; i < num_pages; i++) {
4853		struct page *p = eb->pages[i];
4854
4855		if (p != accessed)
4856			mark_page_accessed(p);
4857	}
4858}
4859
4860struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4861					 u64 start)
4862{
4863	struct extent_buffer *eb;
4864
4865	rcu_read_lock();
4866	eb = radix_tree_lookup(&fs_info->buffer_radix,
4867			       start >> PAGE_SHIFT);
4868	if (eb && atomic_inc_not_zero(&eb->refs)) {
4869		rcu_read_unlock();
4870		/*
4871		 * Lock our eb's refs_lock to avoid races with
4872		 * free_extent_buffer. When we get our eb it might be flagged
4873		 * with EXTENT_BUFFER_STALE and another task running
4874		 * free_extent_buffer might have seen that flag set,
4875		 * eb->refs == 2, that the buffer isn't under IO (dirty and
4876		 * writeback flags not set) and it's still in the tree (flag
4877		 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4878		 * of decrementing the extent buffer's reference count twice.
4879		 * So here we could race and increment the eb's reference count,
4880		 * clear its stale flag, mark it as dirty and drop our reference
4881		 * before the other task finishes executing free_extent_buffer,
4882		 * which would later result in an attempt to free an extent
4883		 * buffer that is dirty.
4884		 */
4885		if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4886			spin_lock(&eb->refs_lock);
4887			spin_unlock(&eb->refs_lock);
4888		}
4889		mark_extent_buffer_accessed(eb, NULL);
4890		return eb;
4891	}
4892	rcu_read_unlock();
4893
4894	return NULL;
4895}
4896
4897#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4898struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4899					u64 start)
4900{
4901	struct extent_buffer *eb, *exists = NULL;
4902	int ret;
4903
4904	eb = find_extent_buffer(fs_info, start);
4905	if (eb)
4906		return eb;
4907	eb = alloc_dummy_extent_buffer(fs_info, start);
4908	if (!eb)
4909		return NULL;
4910	eb->fs_info = fs_info;
4911again:
4912	ret = radix_tree_preload(GFP_NOFS);
4913	if (ret)
 
4914		goto free_eb;
 
4915	spin_lock(&fs_info->buffer_lock);
4916	ret = radix_tree_insert(&fs_info->buffer_radix,
4917				start >> PAGE_SHIFT, eb);
4918	spin_unlock(&fs_info->buffer_lock);
4919	radix_tree_preload_end();
4920	if (ret == -EEXIST) {
4921		exists = find_extent_buffer(fs_info, start);
4922		if (exists)
4923			goto free_eb;
4924		else
4925			goto again;
4926	}
4927	check_buffer_tree_ref(eb);
4928	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4929
4930	/*
4931	 * We will free dummy extent buffer's if they come into
4932	 * free_extent_buffer with a ref count of 2, but if we are using this we
4933	 * want the buffers to stay in memory until we're done with them, so
4934	 * bump the ref count again.
4935	 */
4936	atomic_inc(&eb->refs);
4937	return eb;
4938free_eb:
4939	btrfs_release_extent_buffer(eb);
4940	return exists;
4941}
4942#endif
4943
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4944struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4945					  u64 start)
4946{
4947	unsigned long len = fs_info->nodesize;
4948	unsigned long num_pages = num_extent_pages(start, len);
4949	unsigned long i;
4950	unsigned long index = start >> PAGE_SHIFT;
4951	struct extent_buffer *eb;
4952	struct extent_buffer *exists = NULL;
4953	struct page *p;
4954	struct address_space *mapping = fs_info->btree_inode->i_mapping;
4955	int uptodate = 1;
4956	int ret;
4957
4958	if (!IS_ALIGNED(start, fs_info->sectorsize)) {
4959		btrfs_err(fs_info, "bad tree block start %llu", start);
4960		return ERR_PTR(-EINVAL);
4961	}
4962
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4963	eb = find_extent_buffer(fs_info, start);
4964	if (eb)
4965		return eb;
4966
4967	eb = __alloc_extent_buffer(fs_info, start, len);
4968	if (!eb)
4969		return ERR_PTR(-ENOMEM);
 
4970
 
4971	for (i = 0; i < num_pages; i++, index++) {
 
 
4972		p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4973		if (!p) {
4974			exists = ERR_PTR(-ENOMEM);
4975			goto free_eb;
4976		}
4977
4978		spin_lock(&mapping->private_lock);
4979		if (PagePrivate(p)) {
4980			/*
4981			 * We could have already allocated an eb for this page
4982			 * and attached one so lets see if we can get a ref on
4983			 * the existing eb, and if we can we know it's good and
4984			 * we can just return that one, else we know we can just
4985			 * overwrite page->private.
4986			 */
4987			exists = (struct extent_buffer *)p->private;
4988			if (atomic_inc_not_zero(&exists->refs)) {
4989				spin_unlock(&mapping->private_lock);
4990				unlock_page(p);
4991				put_page(p);
4992				mark_extent_buffer_accessed(exists, p);
4993				goto free_eb;
4994			}
4995			exists = NULL;
4996
4997			/*
4998			 * Do this so attach doesn't complain and we need to
4999			 * drop the ref the old guy had.
5000			 */
5001			ClearPagePrivate(p);
5002			WARN_ON(PageDirty(p));
5003			put_page(p);
 
 
 
5004		}
5005		attach_extent_buffer_page(eb, p);
 
 
 
 
 
 
 
 
 
 
 
 
5006		spin_unlock(&mapping->private_lock);
5007		WARN_ON(PageDirty(p));
 
5008		eb->pages[i] = p;
5009		if (!PageUptodate(p))
5010			uptodate = 0;
5011
5012		/*
5013		 * see below about how we avoid a nasty race with release page
5014		 * and why we unlock later
 
 
 
5015		 */
5016	}
5017	if (uptodate)
5018		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5019again:
5020	ret = radix_tree_preload(GFP_NOFS);
5021	if (ret) {
5022		exists = ERR_PTR(ret);
5023		goto free_eb;
5024	}
5025
5026	spin_lock(&fs_info->buffer_lock);
5027	ret = radix_tree_insert(&fs_info->buffer_radix,
5028				start >> PAGE_SHIFT, eb);
5029	spin_unlock(&fs_info->buffer_lock);
5030	radix_tree_preload_end();
5031	if (ret == -EEXIST) {
5032		exists = find_extent_buffer(fs_info, start);
5033		if (exists)
5034			goto free_eb;
5035		else
5036			goto again;
5037	}
5038	/* add one reference for the tree */
5039	check_buffer_tree_ref(eb);
5040	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5041
5042	/*
5043	 * there is a race where release page may have
5044	 * tried to find this extent buffer in the radix
5045	 * but failed.  It will tell the VM it is safe to
5046	 * reclaim the, and it will clear the page private bit.
5047	 * We must make sure to set the page private bit properly
5048	 * after the extent buffer is in the radix tree so
5049	 * it doesn't get lost
5050	 */
5051	SetPageChecked(eb->pages[0]);
5052	for (i = 1; i < num_pages; i++) {
5053		p = eb->pages[i];
5054		ClearPageChecked(p);
5055		unlock_page(p);
5056	}
5057	unlock_page(eb->pages[0]);
5058	return eb;
5059
5060free_eb:
5061	WARN_ON(!atomic_dec_and_test(&eb->refs));
5062	for (i = 0; i < num_pages; i++) {
5063		if (eb->pages[i])
5064			unlock_page(eb->pages[i]);
5065	}
5066
5067	btrfs_release_extent_buffer(eb);
5068	return exists;
5069}
5070
5071static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5072{
5073	struct extent_buffer *eb =
5074			container_of(head, struct extent_buffer, rcu_head);
5075
5076	__free_extent_buffer(eb);
5077}
5078
5079/* Expects to have eb->eb_lock already held */
5080static int release_extent_buffer(struct extent_buffer *eb)
 
5081{
 
 
5082	WARN_ON(atomic_read(&eb->refs) == 0);
5083	if (atomic_dec_and_test(&eb->refs)) {
5084		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5085			struct btrfs_fs_info *fs_info = eb->fs_info;
5086
5087			spin_unlock(&eb->refs_lock);
5088
5089			spin_lock(&fs_info->buffer_lock);
5090			radix_tree_delete(&fs_info->buffer_radix,
5091					  eb->start >> PAGE_SHIFT);
5092			spin_unlock(&fs_info->buffer_lock);
5093		} else {
5094			spin_unlock(&eb->refs_lock);
5095		}
5096
 
5097		/* Should be safe to release our pages at this point */
5098		btrfs_release_extent_buffer_page(eb);
5099#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5100		if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
5101			__free_extent_buffer(eb);
5102			return 1;
5103		}
5104#endif
5105		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5106		return 1;
5107	}
5108	spin_unlock(&eb->refs_lock);
5109
5110	return 0;
5111}
5112
5113void free_extent_buffer(struct extent_buffer *eb)
5114{
5115	int refs;
5116	int old;
5117	if (!eb)
5118		return;
5119
5120	while (1) {
5121		refs = atomic_read(&eb->refs);
5122		if (refs <= 3)
 
 
5123			break;
5124		old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5125		if (old == refs)
5126			return;
5127	}
5128
5129	spin_lock(&eb->refs_lock);
5130	if (atomic_read(&eb->refs) == 2 &&
5131	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
5132		atomic_dec(&eb->refs);
5133
5134	if (atomic_read(&eb->refs) == 2 &&
5135	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5136	    !extent_buffer_under_io(eb) &&
5137	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5138		atomic_dec(&eb->refs);
5139
5140	/*
5141	 * I know this is terrible, but it's temporary until we stop tracking
5142	 * the uptodate bits and such for the extent buffers.
5143	 */
5144	release_extent_buffer(eb);
5145}
5146
5147void free_extent_buffer_stale(struct extent_buffer *eb)
5148{
5149	if (!eb)
5150		return;
5151
5152	spin_lock(&eb->refs_lock);
5153	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5154
5155	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5156	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5157		atomic_dec(&eb->refs);
5158	release_extent_buffer(eb);
5159}
5160
5161void clear_extent_buffer_dirty(struct extent_buffer *eb)
5162{
5163	unsigned long i;
5164	unsigned long num_pages;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5165	struct page *page;
5166
5167	num_pages = num_extent_pages(eb->start, eb->len);
 
 
 
5168
5169	for (i = 0; i < num_pages; i++) {
5170		page = eb->pages[i];
5171		if (!PageDirty(page))
5172			continue;
5173
5174		lock_page(page);
5175		WARN_ON(!PagePrivate(page));
5176
5177		clear_page_dirty_for_io(page);
5178		xa_lock_irq(&page->mapping->i_pages);
5179		if (!PageDirty(page)) {
5180			radix_tree_tag_clear(&page->mapping->i_pages,
5181						page_index(page),
5182						PAGECACHE_TAG_DIRTY);
5183		}
5184		xa_unlock_irq(&page->mapping->i_pages);
5185		ClearPageError(page);
5186		unlock_page(page);
5187	}
5188	WARN_ON(atomic_read(&eb->refs) == 0);
5189}
5190
5191int set_extent_buffer_dirty(struct extent_buffer *eb)
5192{
5193	unsigned long i;
5194	unsigned long num_pages;
5195	int was_dirty = 0;
5196
5197	check_buffer_tree_ref(eb);
5198
5199	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5200
5201	num_pages = num_extent_pages(eb->start, eb->len);
5202	WARN_ON(atomic_read(&eb->refs) == 0);
5203	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5204
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5205	for (i = 0; i < num_pages; i++)
5206		set_page_dirty(eb->pages[i]);
 
 
5207	return was_dirty;
5208}
5209
5210void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5211{
5212	unsigned long i;
5213	struct page *page;
5214	unsigned long num_pages;
 
5215
5216	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5217	num_pages = num_extent_pages(eb->start, eb->len);
5218	for (i = 0; i < num_pages; i++) {
5219		page = eb->pages[i];
5220		if (page)
5221			ClearPageUptodate(page);
 
5222	}
5223}
5224
5225void set_extent_buffer_uptodate(struct extent_buffer *eb)
5226{
5227	unsigned long i;
5228	struct page *page;
5229	unsigned long num_pages;
 
5230
5231	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5232	num_pages = num_extent_pages(eb->start, eb->len);
5233	for (i = 0; i < num_pages; i++) {
5234		page = eb->pages[i];
5235		SetPageUptodate(page);
5236	}
5237}
5238
5239int read_extent_buffer_pages(struct extent_io_tree *tree,
5240			     struct extent_buffer *eb, int wait, int mirror_num)
5241{
5242	unsigned long i;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5243	struct page *page;
5244	int err;
5245	int ret = 0;
5246	int locked_pages = 0;
5247	int all_uptodate = 1;
5248	unsigned long num_pages;
5249	unsigned long num_reads = 0;
5250	struct bio *bio = NULL;
5251	unsigned long bio_flags = 0;
5252
5253	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5254		return 0;
5255
5256	num_pages = num_extent_pages(eb->start, eb->len);
 
 
 
5257	for (i = 0; i < num_pages; i++) {
5258		page = eb->pages[i];
5259		if (wait == WAIT_NONE) {
 
 
 
 
 
 
 
5260			if (!trylock_page(page))
5261				goto unlock_exit;
5262		} else {
5263			lock_page(page);
5264		}
5265		locked_pages++;
5266	}
5267	/*
5268	 * We need to firstly lock all pages to make sure that
5269	 * the uptodate bit of our pages won't be affected by
5270	 * clear_extent_buffer_uptodate().
5271	 */
5272	for (i = 0; i < num_pages; i++) {
5273		page = eb->pages[i];
5274		if (!PageUptodate(page)) {
5275			num_reads++;
5276			all_uptodate = 0;
5277		}
5278	}
5279
5280	if (all_uptodate) {
5281		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5282		goto unlock_exit;
5283	}
5284
5285	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5286	eb->read_mirror = 0;
5287	atomic_set(&eb->io_pages, num_reads);
 
 
 
 
 
5288	for (i = 0; i < num_pages; i++) {
5289		page = eb->pages[i];
5290
5291		if (!PageUptodate(page)) {
5292			if (ret) {
5293				atomic_dec(&eb->io_pages);
5294				unlock_page(page);
5295				continue;
5296			}
5297
5298			ClearPageError(page);
5299			err = __extent_read_full_page(tree, page,
5300						      btree_get_extent, &bio,
5301						      mirror_num, &bio_flags,
5302						      REQ_META);
5303			if (err) {
5304				ret = err;
5305				/*
5306				 * We use &bio in above __extent_read_full_page,
5307				 * so we ensure that if it returns error, the
5308				 * current page fails to add itself to bio and
5309				 * it's been unlocked.
5310				 *
5311				 * We must dec io_pages by ourselves.
5312				 */
 
 
 
5313				atomic_dec(&eb->io_pages);
5314			}
5315		} else {
5316			unlock_page(page);
5317		}
5318	}
5319
5320	if (bio) {
5321		err = submit_one_bio(bio, mirror_num, bio_flags);
 
5322		if (err)
5323			return err;
5324	}
5325
5326	if (ret || wait != WAIT_COMPLETE)
5327		return ret;
5328
5329	for (i = 0; i < num_pages; i++) {
5330		page = eb->pages[i];
5331		wait_on_page_locked(page);
5332		if (!PageUptodate(page))
5333			ret = -EIO;
5334	}
5335
5336	return ret;
5337
5338unlock_exit:
5339	while (locked_pages > 0) {
5340		locked_pages--;
5341		page = eb->pages[locked_pages];
5342		unlock_page(page);
5343	}
5344	return ret;
5345}
5346
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5347void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
5348			unsigned long start, unsigned long len)
5349{
5350	size_t cur;
5351	size_t offset;
5352	struct page *page;
5353	char *kaddr;
5354	char *dst = (char *)dstv;
5355	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5356	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5357
5358	if (start + len > eb->len) {
5359		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5360		     eb->start, eb->len, start, len);
5361		memset(dst, 0, len);
5362		return;
5363	}
5364
5365	offset = (start_offset + start) & (PAGE_SIZE - 1);
5366
5367	while (len > 0) {
5368		page = eb->pages[i];
5369
5370		cur = min(len, (PAGE_SIZE - offset));
5371		kaddr = page_address(page);
5372		memcpy(dst, kaddr + offset, cur);
5373
5374		dst += cur;
5375		len -= cur;
5376		offset = 0;
5377		i++;
5378	}
5379}
5380
5381int read_extent_buffer_to_user(const struct extent_buffer *eb,
5382			       void __user *dstv,
5383			       unsigned long start, unsigned long len)
5384{
5385	size_t cur;
5386	size_t offset;
5387	struct page *page;
5388	char *kaddr;
5389	char __user *dst = (char __user *)dstv;
5390	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5391	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5392	int ret = 0;
5393
5394	WARN_ON(start > eb->len);
5395	WARN_ON(start + len > eb->start + eb->len);
5396
5397	offset = (start_offset + start) & (PAGE_SIZE - 1);
5398
5399	while (len > 0) {
5400		page = eb->pages[i];
5401
5402		cur = min(len, (PAGE_SIZE - offset));
5403		kaddr = page_address(page);
5404		if (copy_to_user(dst, kaddr + offset, cur)) {
5405			ret = -EFAULT;
5406			break;
5407		}
5408
5409		dst += cur;
5410		len -= cur;
5411		offset = 0;
5412		i++;
5413	}
5414
5415	return ret;
5416}
5417
5418/*
5419 * return 0 if the item is found within a page.
5420 * return 1 if the item spans two pages.
5421 * return -EINVAL otherwise.
5422 */
5423int map_private_extent_buffer(const struct extent_buffer *eb,
5424			      unsigned long start, unsigned long min_len,
5425			      char **map, unsigned long *map_start,
5426			      unsigned long *map_len)
5427{
5428	size_t offset = start & (PAGE_SIZE - 1);
5429	char *kaddr;
5430	struct page *p;
5431	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5432	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5433	unsigned long end_i = (start_offset + start + min_len - 1) >>
5434		PAGE_SHIFT;
5435
5436	if (start + min_len > eb->len) {
5437		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5438		       eb->start, eb->len, start, min_len);
5439		return -EINVAL;
5440	}
5441
5442	if (i != end_i)
5443		return 1;
5444
5445	if (i == 0) {
5446		offset = start_offset;
5447		*map_start = 0;
5448	} else {
5449		offset = 0;
5450		*map_start = ((u64)i << PAGE_SHIFT) - start_offset;
5451	}
5452
5453	p = eb->pages[i];
5454	kaddr = page_address(p);
5455	*map = kaddr + offset;
5456	*map_len = PAGE_SIZE - offset;
5457	return 0;
5458}
5459
5460int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
5461			 unsigned long start, unsigned long len)
5462{
5463	size_t cur;
5464	size_t offset;
5465	struct page *page;
5466	char *kaddr;
5467	char *ptr = (char *)ptrv;
5468	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5469	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5470	int ret = 0;
5471
5472	WARN_ON(start > eb->len);
5473	WARN_ON(start + len > eb->start + eb->len);
5474
5475	offset = (start_offset + start) & (PAGE_SIZE - 1);
5476
5477	while (len > 0) {
5478		page = eb->pages[i];
5479
5480		cur = min(len, (PAGE_SIZE - offset));
5481
5482		kaddr = page_address(page);
5483		ret = memcmp(ptr, kaddr + offset, cur);
5484		if (ret)
5485			break;
5486
5487		ptr += cur;
5488		len -= cur;
5489		offset = 0;
5490		i++;
5491	}
5492	return ret;
5493}
5494
5495void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5496		const void *srcv)
5497{
5498	char *kaddr;
5499
5500	WARN_ON(!PageUptodate(eb->pages[0]));
5501	kaddr = page_address(eb->pages[0]);
5502	memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
5503			BTRFS_FSID_SIZE);
 
5504}
5505
5506void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
5507{
5508	char *kaddr;
5509
5510	WARN_ON(!PageUptodate(eb->pages[0]));
5511	kaddr = page_address(eb->pages[0]);
5512	memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
5513			BTRFS_FSID_SIZE);
5514}
5515
5516void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5517			 unsigned long start, unsigned long len)
5518{
5519	size_t cur;
5520	size_t offset;
5521	struct page *page;
5522	char *kaddr;
5523	char *src = (char *)srcv;
5524	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5525	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5526
5527	WARN_ON(start > eb->len);
5528	WARN_ON(start + len > eb->start + eb->len);
5529
5530	offset = (start_offset + start) & (PAGE_SIZE - 1);
 
 
 
5531
5532	while (len > 0) {
5533		page = eb->pages[i];
5534		WARN_ON(!PageUptodate(page));
5535
5536		cur = min(len, PAGE_SIZE - offset);
5537		kaddr = page_address(page);
5538		memcpy(kaddr + offset, src, cur);
5539
5540		src += cur;
5541		len -= cur;
5542		offset = 0;
5543		i++;
5544	}
5545}
5546
5547void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
5548		unsigned long len)
5549{
5550	size_t cur;
5551	size_t offset;
5552	struct page *page;
5553	char *kaddr;
5554	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5555	unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5556
5557	WARN_ON(start > eb->len);
5558	WARN_ON(start + len > eb->start + eb->len);
5559
5560	offset = (start_offset + start) & (PAGE_SIZE - 1);
5561
5562	while (len > 0) {
5563		page = eb->pages[i];
5564		WARN_ON(!PageUptodate(page));
5565
5566		cur = min(len, PAGE_SIZE - offset);
5567		kaddr = page_address(page);
5568		memset(kaddr + offset, 0, cur);
5569
5570		len -= cur;
5571		offset = 0;
5572		i++;
5573	}
5574}
5575
5576void copy_extent_buffer_full(struct extent_buffer *dst,
5577			     struct extent_buffer *src)
5578{
5579	int i;
5580	unsigned num_pages;
5581
5582	ASSERT(dst->len == src->len);
5583
5584	num_pages = num_extent_pages(dst->start, dst->len);
5585	for (i = 0; i < num_pages; i++)
5586		copy_page(page_address(dst->pages[i]),
5587				page_address(src->pages[i]));
 
 
 
 
 
 
 
 
 
 
5588}
5589
5590void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
 
5591			unsigned long dst_offset, unsigned long src_offset,
5592			unsigned long len)
5593{
5594	u64 dst_len = dst->len;
5595	size_t cur;
5596	size_t offset;
5597	struct page *page;
5598	char *kaddr;
5599	size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5600	unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
 
 
 
5601
5602	WARN_ON(src->len != dst_len);
5603
5604	offset = (start_offset + dst_offset) &
5605		(PAGE_SIZE - 1);
5606
5607	while (len > 0) {
5608		page = dst->pages[i];
5609		WARN_ON(!PageUptodate(page));
5610
5611		cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5612
5613		kaddr = page_address(page);
5614		read_extent_buffer(src, kaddr + offset, src_offset, cur);
5615
5616		src_offset += cur;
5617		len -= cur;
5618		offset = 0;
5619		i++;
5620	}
5621}
5622
5623void le_bitmap_set(u8 *map, unsigned int start, int len)
5624{
5625	u8 *p = map + BIT_BYTE(start);
5626	const unsigned int size = start + len;
5627	int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5628	u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
5629
5630	while (len - bits_to_set >= 0) {
5631		*p |= mask_to_set;
5632		len -= bits_to_set;
5633		bits_to_set = BITS_PER_BYTE;
5634		mask_to_set = ~0;
5635		p++;
5636	}
5637	if (len) {
5638		mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5639		*p |= mask_to_set;
5640	}
5641}
5642
5643void le_bitmap_clear(u8 *map, unsigned int start, int len)
5644{
5645	u8 *p = map + BIT_BYTE(start);
5646	const unsigned int size = start + len;
5647	int bits_to_clear = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5648	u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(start);
5649
5650	while (len - bits_to_clear >= 0) {
5651		*p &= ~mask_to_clear;
5652		len -= bits_to_clear;
5653		bits_to_clear = BITS_PER_BYTE;
5654		mask_to_clear = ~0;
5655		p++;
5656	}
5657	if (len) {
5658		mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5659		*p &= ~mask_to_clear;
5660	}
5661}
5662
5663/*
5664 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5665 * given bit number
5666 * @eb: the extent buffer
5667 * @start: offset of the bitmap item in the extent buffer
5668 * @nr: bit number
5669 * @page_index: return index of the page in the extent buffer that contains the
5670 * given bit number
5671 * @page_offset: return offset into the page given by page_index
5672 *
5673 * This helper hides the ugliness of finding the byte in an extent buffer which
5674 * contains a given bit.
5675 */
5676static inline void eb_bitmap_offset(struct extent_buffer *eb,
5677				    unsigned long start, unsigned long nr,
5678				    unsigned long *page_index,
5679				    size_t *page_offset)
5680{
5681	size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5682	size_t byte_offset = BIT_BYTE(nr);
5683	size_t offset;
5684
5685	/*
5686	 * The byte we want is the offset of the extent buffer + the offset of
5687	 * the bitmap item in the extent buffer + the offset of the byte in the
5688	 * bitmap item.
5689	 */
5690	offset = start_offset + start + byte_offset;
5691
5692	*page_index = offset >> PAGE_SHIFT;
5693	*page_offset = offset & (PAGE_SIZE - 1);
5694}
5695
5696/**
5697 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5698 * @eb: the extent buffer
5699 * @start: offset of the bitmap item in the extent buffer
5700 * @nr: bit number to test
5701 */
5702int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
5703			   unsigned long nr)
5704{
5705	u8 *kaddr;
5706	struct page *page;
5707	unsigned long i;
5708	size_t offset;
5709
5710	eb_bitmap_offset(eb, start, nr, &i, &offset);
5711	page = eb->pages[i];
5712	WARN_ON(!PageUptodate(page));
5713	kaddr = page_address(page);
5714	return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5715}
5716
5717/**
5718 * extent_buffer_bitmap_set - set an area of a bitmap
5719 * @eb: the extent buffer
5720 * @start: offset of the bitmap item in the extent buffer
5721 * @pos: bit number of the first bit
5722 * @len: number of bits to set
5723 */
5724void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
5725			      unsigned long pos, unsigned long len)
5726{
5727	u8 *kaddr;
5728	struct page *page;
5729	unsigned long i;
5730	size_t offset;
5731	const unsigned int size = pos + len;
5732	int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5733	u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5734
5735	eb_bitmap_offset(eb, start, pos, &i, &offset);
5736	page = eb->pages[i];
5737	WARN_ON(!PageUptodate(page));
5738	kaddr = page_address(page);
5739
5740	while (len >= bits_to_set) {
5741		kaddr[offset] |= mask_to_set;
5742		len -= bits_to_set;
5743		bits_to_set = BITS_PER_BYTE;
5744		mask_to_set = ~0;
5745		if (++offset >= PAGE_SIZE && len > 0) {
5746			offset = 0;
5747			page = eb->pages[++i];
5748			WARN_ON(!PageUptodate(page));
5749			kaddr = page_address(page);
5750		}
5751	}
5752	if (len) {
5753		mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5754		kaddr[offset] |= mask_to_set;
5755	}
5756}
5757
5758
5759/**
5760 * extent_buffer_bitmap_clear - clear an area of a bitmap
5761 * @eb: the extent buffer
5762 * @start: offset of the bitmap item in the extent buffer
5763 * @pos: bit number of the first bit
5764 * @len: number of bits to clear
5765 */
5766void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
5767				unsigned long pos, unsigned long len)
 
5768{
5769	u8 *kaddr;
5770	struct page *page;
5771	unsigned long i;
5772	size_t offset;
5773	const unsigned int size = pos + len;
5774	int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5775	u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5776
5777	eb_bitmap_offset(eb, start, pos, &i, &offset);
5778	page = eb->pages[i];
5779	WARN_ON(!PageUptodate(page));
5780	kaddr = page_address(page);
5781
5782	while (len >= bits_to_clear) {
5783		kaddr[offset] &= ~mask_to_clear;
5784		len -= bits_to_clear;
5785		bits_to_clear = BITS_PER_BYTE;
5786		mask_to_clear = ~0;
5787		if (++offset >= PAGE_SIZE && len > 0) {
5788			offset = 0;
5789			page = eb->pages[++i];
5790			WARN_ON(!PageUptodate(page));
5791			kaddr = page_address(page);
5792		}
5793	}
5794	if (len) {
5795		mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5796		kaddr[offset] &= ~mask_to_clear;
5797	}
5798}
5799
5800static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5801{
5802	unsigned long distance = (src > dst) ? src - dst : dst - src;
5803	return distance < len;
5804}
5805
5806static void copy_pages(struct page *dst_page, struct page *src_page,
5807		       unsigned long dst_off, unsigned long src_off,
5808		       unsigned long len)
5809{
5810	char *dst_kaddr = page_address(dst_page);
5811	char *src_kaddr;
5812	int must_memmove = 0;
5813
5814	if (dst_page != src_page) {
5815		src_kaddr = page_address(src_page);
5816	} else {
5817		src_kaddr = dst_kaddr;
5818		if (areas_overlap(src_off, dst_off, len))
5819			must_memmove = 1;
5820	}
5821
5822	if (must_memmove)
5823		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5824	else
5825		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5826}
5827
5828void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5829			   unsigned long src_offset, unsigned long len)
 
5830{
5831	struct btrfs_fs_info *fs_info = dst->fs_info;
5832	size_t cur;
5833	size_t dst_off_in_page;
5834	size_t src_off_in_page;
5835	size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5836	unsigned long dst_i;
5837	unsigned long src_i;
5838
5839	if (src_offset + len > dst->len) {
5840		btrfs_err(fs_info,
5841			"memmove bogus src_offset %lu move len %lu dst len %lu",
5842			 src_offset, len, dst->len);
5843		BUG_ON(1);
5844	}
5845	if (dst_offset + len > dst->len) {
5846		btrfs_err(fs_info,
5847			"memmove bogus dst_offset %lu move len %lu dst len %lu",
5848			 dst_offset, len, dst->len);
5849		BUG_ON(1);
5850	}
5851
5852	while (len > 0) {
5853		dst_off_in_page = (start_offset + dst_offset) &
5854			(PAGE_SIZE - 1);
5855		src_off_in_page = (start_offset + src_offset) &
5856			(PAGE_SIZE - 1);
5857
5858		dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
5859		src_i = (start_offset + src_offset) >> PAGE_SHIFT;
5860
5861		cur = min(len, (unsigned long)(PAGE_SIZE -
5862					       src_off_in_page));
5863		cur = min_t(unsigned long, cur,
5864			(unsigned long)(PAGE_SIZE - dst_off_in_page));
5865
5866		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5867			   dst_off_in_page, src_off_in_page, cur);
5868
5869		src_offset += cur;
5870		dst_offset += cur;
5871		len -= cur;
5872	}
5873}
5874
5875void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5876			   unsigned long src_offset, unsigned long len)
 
5877{
5878	struct btrfs_fs_info *fs_info = dst->fs_info;
5879	size_t cur;
5880	size_t dst_off_in_page;
5881	size_t src_off_in_page;
5882	unsigned long dst_end = dst_offset + len - 1;
5883	unsigned long src_end = src_offset + len - 1;
5884	size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5885	unsigned long dst_i;
5886	unsigned long src_i;
5887
5888	if (src_offset + len > dst->len) {
5889		btrfs_err(fs_info,
5890			  "memmove bogus src_offset %lu move len %lu len %lu",
5891			  src_offset, len, dst->len);
5892		BUG_ON(1);
5893	}
5894	if (dst_offset + len > dst->len) {
5895		btrfs_err(fs_info,
5896			  "memmove bogus dst_offset %lu move len %lu len %lu",
5897			  dst_offset, len, dst->len);
5898		BUG_ON(1);
5899	}
5900	if (dst_offset < src_offset) {
5901		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5902		return;
5903	}
5904	while (len > 0) {
5905		dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
5906		src_i = (start_offset + src_end) >> PAGE_SHIFT;
5907
5908		dst_off_in_page = (start_offset + dst_end) &
5909			(PAGE_SIZE - 1);
5910		src_off_in_page = (start_offset + src_end) &
5911			(PAGE_SIZE - 1);
5912
5913		cur = min_t(unsigned long, len, src_off_in_page + 1);
5914		cur = min(cur, dst_off_in_page + 1);
5915		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5916			   dst_off_in_page - cur + 1,
5917			   src_off_in_page - cur + 1, cur);
5918
5919		dst_end -= cur;
5920		src_end -= cur;
5921		len -= cur;
5922	}
5923}
5924
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5925int try_release_extent_buffer(struct page *page)
5926{
5927	struct extent_buffer *eb;
5928
 
 
 
5929	/*
5930	 * We need to make sure nobody is attaching this page to an eb right
5931	 * now.
5932	 */
5933	spin_lock(&page->mapping->private_lock);
5934	if (!PagePrivate(page)) {
5935		spin_unlock(&page->mapping->private_lock);
5936		return 1;
5937	}
5938
5939	eb = (struct extent_buffer *)page->private;
5940	BUG_ON(!eb);
5941
5942	/*
5943	 * This is a little awful but should be ok, we need to make sure that
5944	 * the eb doesn't disappear out from under us while we're looking at
5945	 * this page.
5946	 */
5947	spin_lock(&eb->refs_lock);
5948	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5949		spin_unlock(&eb->refs_lock);
5950		spin_unlock(&page->mapping->private_lock);
5951		return 0;
5952	}
5953	spin_unlock(&page->mapping->private_lock);
5954
5955	/*
5956	 * If tree ref isn't set then we know the ref on this eb is a real ref,
5957	 * so just return, this page will likely be freed soon anyway.
5958	 */
5959	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5960		spin_unlock(&eb->refs_lock);
5961		return 0;
5962	}
5963
5964	return release_extent_buffer(eb);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5965}