1/*
   2 * Copyright (C) 2007 Oracle.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#include <linux/slab.h>
  20#include <linux/blkdev.h>
  21#include <linux/writeback.h>
  22#include <linux/pagevec.h>
  23#include "ctree.h"
  24#include "transaction.h"
  25#include "btrfs_inode.h"
  26#include "extent_io.h"
  27#include "disk-io.h"
  28#include "compression.h"
  29
  30static struct kmem_cache *btrfs_ordered_extent_cache;
  31
  32static u64 entry_end(struct btrfs_ordered_extent *entry)
  33{
  34	if (entry->file_offset + entry->len < entry->file_offset)
  35		return (u64)-1;
  36	return entry->file_offset + entry->len;
  37}
  38
  39/* returns NULL if the insertion worked, or it returns the node it did find
  40 * in the tree
  41 */
  42static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  43				   struct rb_node *node)
  44{
  45	struct rb_node **p = &root->rb_node;
  46	struct rb_node *parent = NULL;
  47	struct btrfs_ordered_extent *entry;
  48
  49	while (*p) {
  50		parent = *p;
  51		entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  52
  53		if (file_offset < entry->file_offset)
  54			p = &(*p)->rb_left;
  55		else if (file_offset >= entry_end(entry))
  56			p = &(*p)->rb_right;
  57		else
  58			return parent;
  59	}
  60
  61	rb_link_node(node, parent, p);
  62	rb_insert_color(node, root);
  63	return NULL;
  64}
  65
  66static void ordered_data_tree_panic(struct inode *inode, int errno,
  67					       u64 offset)
  68{
  69	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
  70	btrfs_panic(fs_info, errno,
  71		    "Inconsistency in ordered tree at offset %llu", offset);
  72}
  73
  74/*
  75 * look for a given offset in the tree, and if it can't be found return the
  76 * first lesser offset
  77 */
  78static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  79				     struct rb_node **prev_ret)
  80{
  81	struct rb_node *n = root->rb_node;
  82	struct rb_node *prev = NULL;
  83	struct rb_node *test;
  84	struct btrfs_ordered_extent *entry;
  85	struct btrfs_ordered_extent *prev_entry = NULL;
  86
  87	while (n) {
  88		entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  89		prev = n;
  90		prev_entry = entry;
  91
  92		if (file_offset < entry->file_offset)
  93			n = n->rb_left;
  94		else if (file_offset >= entry_end(entry))
  95			n = n->rb_right;
  96		else
  97			return n;
  98	}
  99	if (!prev_ret)
 100		return NULL;
 101
 102	while (prev && file_offset >= entry_end(prev_entry)) {
 103		test = rb_next(prev);
 104		if (!test)
 105			break;
 106		prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 107				      rb_node);
 108		if (file_offset < entry_end(prev_entry))
 109			break;
 110
 111		prev = test;
 112	}
 113	if (prev)
 114		prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 115				      rb_node);
 116	while (prev && file_offset < entry_end(prev_entry)) {
 117		test = rb_prev(prev);
 118		if (!test)
 119			break;
 120		prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 121				      rb_node);
 122		prev = test;
 123	}
 124	*prev_ret = prev;
 125	return NULL;
 126}
 127
 128/*
 129 * helper to check if a given offset is inside a given entry
 130 */
 131static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 132{
 133	if (file_offset < entry->file_offset ||
 134	    entry->file_offset + entry->len <= file_offset)
 135		return 0;
 136	return 1;
 137}
 138
 139static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 140			  u64 len)
 141{
 142	if (file_offset + len <= entry->file_offset ||
 143	    entry->file_offset + entry->len <= file_offset)
 144		return 0;
 145	return 1;
 146}
 147
 148/*
 149 * look find the first ordered struct that has this offset, otherwise
 150 * the first one less than this offset
 151 */
 152static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 153					  u64 file_offset)
 154{
 155	struct rb_root *root = &tree->tree;
 156	struct rb_node *prev = NULL;
 157	struct rb_node *ret;
 158	struct btrfs_ordered_extent *entry;
 159
 160	if (tree->last) {
 161		entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 162				 rb_node);
 163		if (offset_in_entry(entry, file_offset))
 164			return tree->last;
 165	}
 166	ret = __tree_search(root, file_offset, &prev);
 167	if (!ret)
 168		ret = prev;
 169	if (ret)
 170		tree->last = ret;
 171	return ret;
 172}
 173
 174/* allocate and add a new ordered_extent into the per-inode tree.
 175 * file_offset is the logical offset in the file
 176 *
 177 * start is the disk block number of an extent already reserved in the
 178 * extent allocation tree
 179 *
 180 * len is the length of the extent
 181 *
 182 * The tree is given a single reference on the ordered extent that was
 183 * inserted.
 184 */
 185static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 186				      u64 start, u64 len, u64 disk_len,
 187				      int type, int dio, int compress_type)
 188{
 189	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 190	struct btrfs_root *root = BTRFS_I(inode)->root;
 191	struct btrfs_ordered_inode_tree *tree;
 192	struct rb_node *node;
 193	struct btrfs_ordered_extent *entry;
 194
 195	tree = &BTRFS_I(inode)->ordered_tree;
 196	entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 197	if (!entry)
 198		return -ENOMEM;
 199
 200	entry->file_offset = file_offset;
 201	entry->start = start;
 202	entry->len = len;
 203	entry->disk_len = disk_len;
 204	entry->bytes_left = len;
 205	entry->inode = igrab(inode);
 206	entry->compress_type = compress_type;
 207	entry->truncated_len = (u64)-1;
 208	if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 209		set_bit(type, &entry->flags);
 210
 211	if (dio)
 212		set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 213
 214	/* one ref for the tree */
 215	atomic_set(&entry->refs, 1);
 216	init_waitqueue_head(&entry->wait);
 217	INIT_LIST_HEAD(&entry->list);
 218	INIT_LIST_HEAD(&entry->root_extent_list);
 219	INIT_LIST_HEAD(&entry->work_list);
 220	init_completion(&entry->completion);
 221	INIT_LIST_HEAD(&entry->log_list);
 222	INIT_LIST_HEAD(&entry->trans_list);
 223
 224	trace_btrfs_ordered_extent_add(inode, entry);
 225
 226	spin_lock_irq(&tree->lock);
 227	node = tree_insert(&tree->tree, file_offset,
 228			   &entry->rb_node);
 229	if (node)
 230		ordered_data_tree_panic(inode, -EEXIST, file_offset);
 231	spin_unlock_irq(&tree->lock);
 232
 233	spin_lock(&root->ordered_extent_lock);
 234	list_add_tail(&entry->root_extent_list,
 235		      &root->ordered_extents);
 236	root->nr_ordered_extents++;
 237	if (root->nr_ordered_extents == 1) {
 238		spin_lock(&fs_info->ordered_root_lock);
 239		BUG_ON(!list_empty(&root->ordered_root));
 240		list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 241		spin_unlock(&fs_info->ordered_root_lock);
 
 242	}
 243	spin_unlock(&root->ordered_extent_lock);
 244
 245	return 0;
 246}
 247
 248int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 249			     u64 start, u64 len, u64 disk_len, int type)
 250{
 251	return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 252					  disk_len, type, 0,
 253					  BTRFS_COMPRESS_NONE);
 254}
 255
 256int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 257				 u64 start, u64 len, u64 disk_len, int type)
 258{
 259	return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 260					  disk_len, type, 1,
 261					  BTRFS_COMPRESS_NONE);
 262}
 263
 264int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 265				      u64 start, u64 len, u64 disk_len,
 266				      int type, int compress_type)
 267{
 268	return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 269					  disk_len, type, 0,
 270					  compress_type);
 271}
 272
 273/*
 274 * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 275 * when an ordered extent is finished.  If the list covers more than one
 276 * ordered extent, it is split across multiples.
 277 */
 278void btrfs_add_ordered_sum(struct inode *inode,
 279			   struct btrfs_ordered_extent *entry,
 280			   struct btrfs_ordered_sum *sum)
 281{
 282	struct btrfs_ordered_inode_tree *tree;
 283
 284	tree = &BTRFS_I(inode)->ordered_tree;
 285	spin_lock_irq(&tree->lock);
 286	list_add_tail(&sum->list, &entry->list);
 287	spin_unlock_irq(&tree->lock);
 288}
 289
 290/*
 291 * this is used to account for finished IO across a given range
 292 * of the file.  The IO may span ordered extents.  If
 293 * a given ordered_extent is completely done, 1 is returned, otherwise
 294 * 0.
 295 *
 296 * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 297 * to make sure this function only returns 1 once for a given ordered extent.
 298 *
 299 * file_offset is updated to one byte past the range that is recorded as
 300 * complete.  This allows you to walk forward in the file.
 301 */
 302int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 303				   struct btrfs_ordered_extent **cached,
 304				   u64 *file_offset, u64 io_size, int uptodate)
 305{
 306	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 307	struct btrfs_ordered_inode_tree *tree;
 308	struct rb_node *node;
 309	struct btrfs_ordered_extent *entry = NULL;
 310	int ret;
 311	unsigned long flags;
 312	u64 dec_end;
 313	u64 dec_start;
 314	u64 to_dec;
 315
 316	tree = &BTRFS_I(inode)->ordered_tree;
 317	spin_lock_irqsave(&tree->lock, flags);
 318	node = tree_search(tree, *file_offset);
 319	if (!node) {
 320		ret = 1;
 321		goto out;
 322	}
 323
 324	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 325	if (!offset_in_entry(entry, *file_offset)) {
 326		ret = 1;
 327		goto out;
 328	}
 329
 330	dec_start = max(*file_offset, entry->file_offset);
 331	dec_end = min(*file_offset + io_size, entry->file_offset +
 332		      entry->len);
 333	*file_offset = dec_end;
 334	if (dec_start > dec_end) {
 335		btrfs_crit(fs_info, "bad ordering dec_start %llu end %llu",
 336			   dec_start, dec_end);
 337	}
 338	to_dec = dec_end - dec_start;
 339	if (to_dec > entry->bytes_left) {
 340		btrfs_crit(fs_info,
 341			   "bad ordered accounting left %llu size %llu",
 342			   entry->bytes_left, to_dec);
 343	}
 344	entry->bytes_left -= to_dec;
 345	if (!uptodate)
 346		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 347
 348	if (entry->bytes_left == 0) {
 349		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 350		/*
 351		 * Implicit memory barrier after test_and_set_bit
 352		 */
 353		if (waitqueue_active(&entry->wait))
 354			wake_up(&entry->wait);
 355	} else {
 356		ret = 1;
 357	}
 358out:
 359	if (!ret && cached && entry) {
 360		*cached = entry;
 361		atomic_inc(&entry->refs);
 362	}
 363	spin_unlock_irqrestore(&tree->lock, flags);
 364	return ret == 0;
 365}
 366
 367/*
 368 * this is used to account for finished IO across a given range
 369 * of the file.  The IO should not span ordered extents.  If
 370 * a given ordered_extent is completely done, 1 is returned, otherwise
 371 * 0.
 372 *
 373 * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 374 * to make sure this function only returns 1 once for a given ordered extent.
 375 */
 376int btrfs_dec_test_ordered_pending(struct inode *inode,
 377				   struct btrfs_ordered_extent **cached,
 378				   u64 file_offset, u64 io_size, int uptodate)
 379{
 380	struct btrfs_ordered_inode_tree *tree;
 381	struct rb_node *node;
 382	struct btrfs_ordered_extent *entry = NULL;
 383	unsigned long flags;
 384	int ret;
 385
 386	tree = &BTRFS_I(inode)->ordered_tree;
 387	spin_lock_irqsave(&tree->lock, flags);
 388	if (cached && *cached) {
 389		entry = *cached;
 390		goto have_entry;
 391	}
 392
 393	node = tree_search(tree, file_offset);
 394	if (!node) {
 395		ret = 1;
 396		goto out;
 397	}
 398
 399	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 400have_entry:
 401	if (!offset_in_entry(entry, file_offset)) {
 402		ret = 1;
 403		goto out;
 404	}
 405
 406	if (io_size > entry->bytes_left) {
 407		btrfs_crit(BTRFS_I(inode)->root->fs_info,
 408			   "bad ordered accounting left %llu size %llu",
 409		       entry->bytes_left, io_size);
 410	}
 411	entry->bytes_left -= io_size;
 412	if (!uptodate)
 413		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 414
 415	if (entry->bytes_left == 0) {
 416		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 417		/*
 418		 * Implicit memory barrier after test_and_set_bit
 419		 */
 420		if (waitqueue_active(&entry->wait))
 421			wake_up(&entry->wait);
 422	} else {
 423		ret = 1;
 424	}
 425out:
 426	if (!ret && cached && entry) {
 427		*cached = entry;
 428		atomic_inc(&entry->refs);
 429	}
 430	spin_unlock_irqrestore(&tree->lock, flags);
 431	return ret == 0;
 432}
 433
 434/* Needs to either be called under a log transaction or the log_mutex */
 435void btrfs_get_logged_extents(struct inode *inode,
 436			      struct list_head *logged_list,
 437			      const loff_t start,
 438			      const loff_t end)
 439{
 440	struct btrfs_ordered_inode_tree *tree;
 441	struct btrfs_ordered_extent *ordered;
 442	struct rb_node *n;
 443	struct rb_node *prev;
 444
 445	tree = &BTRFS_I(inode)->ordered_tree;
 446	spin_lock_irq(&tree->lock);
 447	n = __tree_search(&tree->tree, end, &prev);
 448	if (!n)
 449		n = prev;
 450	for (; n; n = rb_prev(n)) {
 451		ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 452		if (ordered->file_offset > end)
 453			continue;
 454		if (entry_end(ordered) <= start)
 455			break;
 456		if (test_and_set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 457			continue;
 458		list_add(&ordered->log_list, logged_list);
 459		atomic_inc(&ordered->refs);
 460	}
 461	spin_unlock_irq(&tree->lock);
 462}
 463
 464void btrfs_put_logged_extents(struct list_head *logged_list)
 465{
 466	struct btrfs_ordered_extent *ordered;
 467
 468	while (!list_empty(logged_list)) {
 469		ordered = list_first_entry(logged_list,
 470					   struct btrfs_ordered_extent,
 471					   log_list);
 472		list_del_init(&ordered->log_list);
 473		btrfs_put_ordered_extent(ordered);
 474	}
 475}
 476
 477void btrfs_submit_logged_extents(struct list_head *logged_list,
 478				 struct btrfs_root *log)
 479{
 480	int index = log->log_transid % 2;
 481
 482	spin_lock_irq(&log->log_extents_lock[index]);
 483	list_splice_tail(logged_list, &log->logged_list[index]);
 484	spin_unlock_irq(&log->log_extents_lock[index]);
 485}
 486
 487void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
 488			       struct btrfs_root *log, u64 transid)
 489{
 490	struct btrfs_ordered_extent *ordered;
 491	int index = transid % 2;
 492
 493	spin_lock_irq(&log->log_extents_lock[index]);
 494	while (!list_empty(&log->logged_list[index])) {
 495		struct inode *inode;
 496		ordered = list_first_entry(&log->logged_list[index],
 497					   struct btrfs_ordered_extent,
 498					   log_list);
 499		list_del_init(&ordered->log_list);
 500		inode = ordered->inode;
 501		spin_unlock_irq(&log->log_extents_lock[index]);
 502
 503		if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
 504		    !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
 505			u64 start = ordered->file_offset;
 506			u64 end = ordered->file_offset + ordered->len - 1;
 507
 508			WARN_ON(!inode);
 509			filemap_fdatawrite_range(inode->i_mapping, start, end);
 510		}
 511		wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
 512						   &ordered->flags));
 513
 514		/*
 515		 * In order to keep us from losing our ordered extent
 516		 * information when committing the transaction we have to make
 517		 * sure that any logged extents are completed when we go to
 518		 * commit the transaction.  To do this we simply increase the
 519		 * current transactions pending_ordered counter and decrement it
 520		 * when the ordered extent completes.
 521		 */
 522		if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
 523			struct btrfs_ordered_inode_tree *tree;
 524
 525			tree = &BTRFS_I(inode)->ordered_tree;
 526			spin_lock_irq(&tree->lock);
 527			if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
 528				set_bit(BTRFS_ORDERED_PENDING, &ordered->flags);
 529				atomic_inc(&trans->transaction->pending_ordered);
 530			}
 531			spin_unlock_irq(&tree->lock);
 532		}
 533		btrfs_put_ordered_extent(ordered);
 534		spin_lock_irq(&log->log_extents_lock[index]);
 535	}
 536	spin_unlock_irq(&log->log_extents_lock[index]);
 537}
 538
 539void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
 540{
 541	struct btrfs_ordered_extent *ordered;
 542	int index = transid % 2;
 543
 544	spin_lock_irq(&log->log_extents_lock[index]);
 545	while (!list_empty(&log->logged_list[index])) {
 546		ordered = list_first_entry(&log->logged_list[index],
 547					   struct btrfs_ordered_extent,
 548					   log_list);
 549		list_del_init(&ordered->log_list);
 550		spin_unlock_irq(&log->log_extents_lock[index]);
 551		btrfs_put_ordered_extent(ordered);
 552		spin_lock_irq(&log->log_extents_lock[index]);
 553	}
 554	spin_unlock_irq(&log->log_extents_lock[index]);
 555}
 556
 557/*
 558 * used to drop a reference on an ordered extent.  This will free
 559 * the extent if the last reference is dropped
 560 */
 561void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 562{
 563	struct list_head *cur;
 564	struct btrfs_ordered_sum *sum;
 565
 566	trace_btrfs_ordered_extent_put(entry->inode, entry);
 567
 568	if (atomic_dec_and_test(&entry->refs)) {
 569		ASSERT(list_empty(&entry->log_list));
 570		ASSERT(list_empty(&entry->trans_list));
 571		ASSERT(list_empty(&entry->root_extent_list));
 572		ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 573		if (entry->inode)
 574			btrfs_add_delayed_iput(entry->inode);
 575		while (!list_empty(&entry->list)) {
 576			cur = entry->list.next;
 577			sum = list_entry(cur, struct btrfs_ordered_sum, list);
 578			list_del(&sum->list);
 579			kfree(sum);
 580		}
 581		kmem_cache_free(btrfs_ordered_extent_cache, entry);
 582	}
 583}
 584
 585/*
 586 * remove an ordered extent from the tree.  No references are dropped
 587 * and waiters are woken up.
 588 */
 589void btrfs_remove_ordered_extent(struct inode *inode,
 590				 struct btrfs_ordered_extent *entry)
 591{
 592	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 593	struct btrfs_ordered_inode_tree *tree;
 594	struct btrfs_root *root = BTRFS_I(inode)->root;
 595	struct rb_node *node;
 596	bool dec_pending_ordered = false;
 597
 598	tree = &BTRFS_I(inode)->ordered_tree;
 599	spin_lock_irq(&tree->lock);
 600	node = &entry->rb_node;
 601	rb_erase(node, &tree->tree);
 602	RB_CLEAR_NODE(node);
 603	if (tree->last == node)
 604		tree->last = NULL;
 605	set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 606	if (test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags))
 607		dec_pending_ordered = true;
 608	spin_unlock_irq(&tree->lock);
 609
 610	/*
 611	 * The current running transaction is waiting on us, we need to let it
 612	 * know that we're complete and wake it up.
 613	 */
 614	if (dec_pending_ordered) {
 615		struct btrfs_transaction *trans;
 616
 617		/*
 618		 * The checks for trans are just a formality, it should be set,
 619		 * but if it isn't we don't want to deref/assert under the spin
 620		 * lock, so be nice and check if trans is set, but ASSERT() so
 621		 * if it isn't set a developer will notice.
 622		 */
 623		spin_lock(&fs_info->trans_lock);
 624		trans = fs_info->running_transaction;
 625		if (trans)
 626			atomic_inc(&trans->use_count);
 627		spin_unlock(&fs_info->trans_lock);
 628
 629		ASSERT(trans);
 630		if (trans) {
 631			if (atomic_dec_and_test(&trans->pending_ordered))
 632				wake_up(&trans->pending_wait);
 633			btrfs_put_transaction(trans);
 634		}
 635	}
 636
 637	spin_lock(&root->ordered_extent_lock);
 638	list_del_init(&entry->root_extent_list);
 639	root->nr_ordered_extents--;
 640
 641	trace_btrfs_ordered_extent_remove(inode, entry);
 642
 643	if (!root->nr_ordered_extents) {
 644		spin_lock(&fs_info->ordered_root_lock);
 645		BUG_ON(list_empty(&root->ordered_root));
 646		list_del_init(&root->ordered_root);
 647		spin_unlock(&fs_info->ordered_root_lock);
 648	}
 649	spin_unlock(&root->ordered_extent_lock);
 650	wake_up(&entry->wait);
 651}
 652
 653static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 654{
 655	struct btrfs_ordered_extent *ordered;
 656
 657	ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 658	btrfs_start_ordered_extent(ordered->inode, ordered, 1);
 659	complete(&ordered->completion);
 660}
 661
 662/*
 663 * wait for all the ordered extents in a root.  This is done when balancing
 664 * space between drives.
 665 */
 666int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr,
 667			       const u64 range_start, const u64 range_len)
 668{
 669	struct btrfs_fs_info *fs_info = root->fs_info;
 670	LIST_HEAD(splice);
 671	LIST_HEAD(skipped);
 672	LIST_HEAD(works);
 673	struct btrfs_ordered_extent *ordered, *next;
 674	int count = 0;
 675	const u64 range_end = range_start + range_len;
 
 
 676
 677	mutex_lock(&root->ordered_extent_mutex);
 678	spin_lock(&root->ordered_extent_lock);
 679	list_splice_init(&root->ordered_extents, &splice);
 680	while (!list_empty(&splice) && nr) {
 681		ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 682					   root_extent_list);
 683
 684		if (range_end <= ordered->start ||
 685		    ordered->start + ordered->disk_len <= range_start) {
 686			list_move_tail(&ordered->root_extent_list, &skipped);
 687			cond_resched_lock(&root->ordered_extent_lock);
 688			continue;
 689		}
 690
 691		list_move_tail(&ordered->root_extent_list,
 692			       &root->ordered_extents);
 693		atomic_inc(&ordered->refs);
 694		spin_unlock(&root->ordered_extent_lock);
 695
 696		btrfs_init_work(&ordered->flush_work,
 697				btrfs_flush_delalloc_helper,
 698				btrfs_run_ordered_extent_work, NULL, NULL);
 699		list_add_tail(&ordered->work_list, &works);
 700		btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 
 701
 702		cond_resched();
 703		spin_lock(&root->ordered_extent_lock);
 704		if (nr != -1)
 705			nr--;
 706		count++;
 707	}
 708	list_splice_tail(&skipped, &root->ordered_extents);
 709	list_splice_tail(&splice, &root->ordered_extents);
 710	spin_unlock(&root->ordered_extent_lock);
 711
 712	list_for_each_entry_safe(ordered, next, &works, work_list) {
 713		list_del_init(&ordered->work_list);
 714		wait_for_completion(&ordered->completion);
 715		btrfs_put_ordered_extent(ordered);
 716		cond_resched();
 717	}
 718	mutex_unlock(&root->ordered_extent_mutex);
 719
 720	return count;
 721}
 722
 723int btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr,
 724			      const u64 range_start, const u64 range_len)
 725{
 726	struct btrfs_root *root;
 727	struct list_head splice;
 728	int done;
 729	int total_done = 0;
 730
 731	INIT_LIST_HEAD(&splice);
 732
 733	mutex_lock(&fs_info->ordered_operations_mutex);
 734	spin_lock(&fs_info->ordered_root_lock);
 735	list_splice_init(&fs_info->ordered_roots, &splice);
 736	while (!list_empty(&splice) && nr) {
 737		root = list_first_entry(&splice, struct btrfs_root,
 738					ordered_root);
 739		root = btrfs_grab_fs_root(root);
 740		BUG_ON(!root);
 741		list_move_tail(&root->ordered_root,
 742			       &fs_info->ordered_roots);
 743		spin_unlock(&fs_info->ordered_root_lock);
 744
 745		done = btrfs_wait_ordered_extents(root, nr,
 746						  range_start, range_len);
 747		btrfs_put_fs_root(root);
 748		total_done += done;
 749
 750		spin_lock(&fs_info->ordered_root_lock);
 751		if (nr != -1) {
 752			nr -= done;
 753			WARN_ON(nr < 0);
 754		}
 755	}
 756	list_splice_tail(&splice, &fs_info->ordered_roots);
 757	spin_unlock(&fs_info->ordered_root_lock);
 758	mutex_unlock(&fs_info->ordered_operations_mutex);
 759
 760	return total_done;
 761}
 762
 763/*
 764 * Used to start IO or wait for a given ordered extent to finish.
 765 *
 766 * If wait is one, this effectively waits on page writeback for all the pages
 767 * in the extent, and it waits on the io completion code to insert
 768 * metadata into the btree corresponding to the extent
 769 */
 770void btrfs_start_ordered_extent(struct inode *inode,
 771				       struct btrfs_ordered_extent *entry,
 772				       int wait)
 773{
 774	u64 start = entry->file_offset;
 775	u64 end = start + entry->len - 1;
 776
 777	trace_btrfs_ordered_extent_start(inode, entry);
 778
 779	/*
 780	 * pages in the range can be dirty, clean or writeback.  We
 781	 * start IO on any dirty ones so the wait doesn't stall waiting
 782	 * for the flusher thread to find them
 783	 */
 784	if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 785		filemap_fdatawrite_range(inode->i_mapping, start, end);
 786	if (wait) {
 787		wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 788						 &entry->flags));
 789	}
 790}
 791
 792/*
 793 * Used to wait on ordered extents across a large range of bytes.
 794 */
 795int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 796{
 797	int ret = 0;
 798	int ret_wb = 0;
 799	u64 end;
 800	u64 orig_end;
 801	struct btrfs_ordered_extent *ordered;
 802
 803	if (start + len < start) {
 804		orig_end = INT_LIMIT(loff_t);
 805	} else {
 806		orig_end = start + len - 1;
 807		if (orig_end > INT_LIMIT(loff_t))
 808			orig_end = INT_LIMIT(loff_t);
 809	}
 810
 811	/* start IO across the range first to instantiate any delalloc
 812	 * extents
 813	 */
 814	ret = btrfs_fdatawrite_range(inode, start, orig_end);
 815	if (ret)
 816		return ret;
 817
 818	/*
 819	 * If we have a writeback error don't return immediately. Wait first
 820	 * for any ordered extents that haven't completed yet. This is to make
 821	 * sure no one can dirty the same page ranges and call writepages()
 822	 * before the ordered extents complete - to avoid failures (-EEXIST)
 823	 * when adding the new ordered extents to the ordered tree.
 824	 */
 825	ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 826
 827	end = orig_end;
 828	while (1) {
 829		ordered = btrfs_lookup_first_ordered_extent(inode, end);
 830		if (!ordered)
 831			break;
 832		if (ordered->file_offset > orig_end) {
 833			btrfs_put_ordered_extent(ordered);
 834			break;
 835		}
 836		if (ordered->file_offset + ordered->len <= start) {
 837			btrfs_put_ordered_extent(ordered);
 838			break;
 839		}
 840		btrfs_start_ordered_extent(inode, ordered, 1);
 841		end = ordered->file_offset;
 842		if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 843			ret = -EIO;
 844		btrfs_put_ordered_extent(ordered);
 845		if (ret || end == 0 || end == start)
 846			break;
 847		end--;
 848	}
 849	return ret_wb ? ret_wb : ret;
 850}
 851
 852/*
 853 * find an ordered extent corresponding to file_offset.  return NULL if
 854 * nothing is found, otherwise take a reference on the extent and return it
 855 */
 856struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 857							 u64 file_offset)
 858{
 859	struct btrfs_ordered_inode_tree *tree;
 860	struct rb_node *node;
 861	struct btrfs_ordered_extent *entry = NULL;
 862
 863	tree = &BTRFS_I(inode)->ordered_tree;
 864	spin_lock_irq(&tree->lock);
 865	node = tree_search(tree, file_offset);
 866	if (!node)
 867		goto out;
 868
 869	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 870	if (!offset_in_entry(entry, file_offset))
 871		entry = NULL;
 872	if (entry)
 873		atomic_inc(&entry->refs);
 874out:
 875	spin_unlock_irq(&tree->lock);
 876	return entry;
 877}
 878
 879/* Since the DIO code tries to lock a wide area we need to look for any ordered
 880 * extents that exist in the range, rather than just the start of the range.
 881 */
 882struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
 883							u64 file_offset,
 884							u64 len)
 885{
 886	struct btrfs_ordered_inode_tree *tree;
 887	struct rb_node *node;
 888	struct btrfs_ordered_extent *entry = NULL;
 889
 890	tree = &BTRFS_I(inode)->ordered_tree;
 891	spin_lock_irq(&tree->lock);
 892	node = tree_search(tree, file_offset);
 893	if (!node) {
 894		node = tree_search(tree, file_offset + len);
 895		if (!node)
 896			goto out;
 897	}
 898
 899	while (1) {
 900		entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 901		if (range_overlaps(entry, file_offset, len))
 902			break;
 903
 904		if (entry->file_offset >= file_offset + len) {
 905			entry = NULL;
 906			break;
 907		}
 908		entry = NULL;
 909		node = rb_next(node);
 910		if (!node)
 911			break;
 912	}
 913out:
 914	if (entry)
 915		atomic_inc(&entry->refs);
 916	spin_unlock_irq(&tree->lock);
 917	return entry;
 918}
 919
 920bool btrfs_have_ordered_extents_in_range(struct inode *inode,
 921					 u64 file_offset,
 922					 u64 len)
 923{
 924	struct btrfs_ordered_extent *oe;
 925
 926	oe = btrfs_lookup_ordered_range(inode, file_offset, len);
 927	if (oe) {
 928		btrfs_put_ordered_extent(oe);
 929		return true;
 930	}
 931	return false;
 932}
 933
 934/*
 935 * lookup and return any extent before 'file_offset'.  NULL is returned
 936 * if none is found
 937 */
 938struct btrfs_ordered_extent *
 939btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 940{
 941	struct btrfs_ordered_inode_tree *tree;
 942	struct rb_node *node;
 943	struct btrfs_ordered_extent *entry = NULL;
 944
 945	tree = &BTRFS_I(inode)->ordered_tree;
 946	spin_lock_irq(&tree->lock);
 947	node = tree_search(tree, file_offset);
 948	if (!node)
 949		goto out;
 950
 951	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 952	atomic_inc(&entry->refs);
 953out:
 954	spin_unlock_irq(&tree->lock);
 955	return entry;
 956}
 957
 958/*
 959 * After an extent is done, call this to conditionally update the on disk
 960 * i_size.  i_size is updated to cover any fully written part of the file.
 961 */
 962int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 963				struct btrfs_ordered_extent *ordered)
 964{
 965	struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 966	u64 disk_i_size;
 967	u64 new_i_size;
 968	u64 i_size = i_size_read(inode);
 969	struct rb_node *node;
 970	struct rb_node *prev = NULL;
 971	struct btrfs_ordered_extent *test;
 972	int ret = 1;
 973	u64 orig_offset = offset;
 974
 975	spin_lock_irq(&tree->lock);
 976	if (ordered) {
 977		offset = entry_end(ordered);
 978		if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
 979			offset = min(offset,
 980				     ordered->file_offset +
 981				     ordered->truncated_len);
 982	} else {
 983		offset = ALIGN(offset, btrfs_inode_sectorsize(inode));
 984	}
 985	disk_i_size = BTRFS_I(inode)->disk_i_size;
 986
 987	/* truncate file */
 988	if (disk_i_size > i_size) {
 989		BTRFS_I(inode)->disk_i_size = orig_offset;
 990		ret = 0;
 991		goto out;
 992	}
 993
 994	/*
 995	 * if the disk i_size is already at the inode->i_size, or
 996	 * this ordered extent is inside the disk i_size, we're done
 997	 */
 998	if (disk_i_size == i_size)
 999		goto out;
1000
1001	/*
1002	 * We still need to update disk_i_size if outstanding_isize is greater
1003	 * than disk_i_size.
1004	 */
1005	if (offset <= disk_i_size &&
1006	    (!ordered || ordered->outstanding_isize <= disk_i_size))
1007		goto out;
1008
1009	/*
1010	 * walk backward from this ordered extent to disk_i_size.
1011	 * if we find an ordered extent then we can't update disk i_size
1012	 * yet
1013	 */
1014	if (ordered) {
1015		node = rb_prev(&ordered->rb_node);
1016	} else {
1017		prev = tree_search(tree, offset);
1018		/*
1019		 * we insert file extents without involving ordered struct,
1020		 * so there should be no ordered struct cover this offset
1021		 */
1022		if (prev) {
1023			test = rb_entry(prev, struct btrfs_ordered_extent,
1024					rb_node);
1025			BUG_ON(offset_in_entry(test, offset));
1026		}
1027		node = prev;
1028	}
1029	for (; node; node = rb_prev(node)) {
1030		test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1031
1032		/* We treat this entry as if it doesn't exist */
1033		if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
1034			continue;
1035		if (test->file_offset + test->len <= disk_i_size)
1036			break;
1037		if (test->file_offset >= i_size)
1038			break;
1039		if (entry_end(test) > disk_i_size) {
1040			/*
1041			 * we don't update disk_i_size now, so record this
1042			 * undealt i_size. Or we will not know the real
1043			 * i_size.
1044			 */
1045			if (test->outstanding_isize < offset)
1046				test->outstanding_isize = offset;
1047			if (ordered &&
1048			    ordered->outstanding_isize >
1049			    test->outstanding_isize)
1050				test->outstanding_isize =
1051						ordered->outstanding_isize;
1052			goto out;
1053		}
1054	}
1055	new_i_size = min_t(u64, offset, i_size);
1056
1057	/*
1058	 * Some ordered extents may completed before the current one, and
1059	 * we hold the real i_size in ->outstanding_isize.
1060	 */
1061	if (ordered && ordered->outstanding_isize > new_i_size)
1062		new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
1063	BTRFS_I(inode)->disk_i_size = new_i_size;
1064	ret = 0;
1065out:
1066	/*
1067	 * We need to do this because we can't remove ordered extents until
1068	 * after the i_disk_size has been updated and then the inode has been
1069	 * updated to reflect the change, so we need to tell anybody who finds
1070	 * this ordered extent that we've already done all the real work, we
1071	 * just haven't completed all the other work.
1072	 */
1073	if (ordered)
1074		set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
1075	spin_unlock_irq(&tree->lock);
1076	return ret;
1077}
1078
1079/*
1080 * search the ordered extents for one corresponding to 'offset' and
1081 * try to find a checksum.  This is used because we allow pages to
1082 * be reclaimed before their checksum is actually put into the btree
1083 */
1084int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
1085			   u32 *sum, int len)
1086{
1087	struct btrfs_ordered_sum *ordered_sum;
1088	struct btrfs_ordered_extent *ordered;
1089	struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
1090	unsigned long num_sectors;
1091	unsigned long i;
1092	u32 sectorsize = btrfs_inode_sectorsize(inode);
1093	int index = 0;
1094
1095	ordered = btrfs_lookup_ordered_extent(inode, offset);
1096	if (!ordered)
1097		return 0;
1098
1099	spin_lock_irq(&tree->lock);
1100	list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
1101		if (disk_bytenr >= ordered_sum->bytenr &&
1102		    disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
1103			i = (disk_bytenr - ordered_sum->bytenr) >>
1104			    inode->i_sb->s_blocksize_bits;
1105			num_sectors = ordered_sum->len >>
1106				      inode->i_sb->s_blocksize_bits;
1107			num_sectors = min_t(int, len - index, num_sectors - i);
1108			memcpy(sum + index, ordered_sum->sums + i,
1109			       num_sectors);
1110
1111			index += (int)num_sectors;
1112			if (index == len)
1113				goto out;
1114			disk_bytenr += num_sectors * sectorsize;
1115		}
1116	}
1117out:
1118	spin_unlock_irq(&tree->lock);
1119	btrfs_put_ordered_extent(ordered);
1120	return index;
1121}
1122
1123int __init ordered_data_init(void)
1124{
1125	btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1126				     sizeof(struct btrfs_ordered_extent), 0,
1127				     SLAB_MEM_SPREAD,
1128				     NULL);
1129	if (!btrfs_ordered_extent_cache)
1130		return -ENOMEM;
1131
1132	return 0;
1133}
1134
1135void ordered_data_exit(void)
1136{
1137	kmem_cache_destroy(btrfs_ordered_extent_cache);
1138}