1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2011 Fujitsu.  All rights reserved.
   4 * Written by Miao Xie <miaox@cn.fujitsu.com>
   5 */
   6
   7#include <linux/slab.h>
   8#include <linux/iversion.h>
   9#include "ctree.h"
  10#include "fs.h"
  11#include "messages.h"
  12#include "misc.h"
  13#include "delayed-inode.h"
  14#include "disk-io.h"
  15#include "transaction.h"
 
  16#include "qgroup.h"
  17#include "locking.h"
  18#include "inode-item.h"
  19#include "space-info.h"
  20#include "accessors.h"
  21#include "file-item.h"
  22
  23#define BTRFS_DELAYED_WRITEBACK		512
  24#define BTRFS_DELAYED_BACKGROUND	128
  25#define BTRFS_DELAYED_BATCH		16
  26
  27static struct kmem_cache *delayed_node_cache;
  28
  29int __init btrfs_delayed_inode_init(void)
  30{
  31	delayed_node_cache = kmem_cache_create("btrfs_delayed_node",
  32					sizeof(struct btrfs_delayed_node),
  33					0,
  34					SLAB_MEM_SPREAD,
  35					NULL);
  36	if (!delayed_node_cache)
  37		return -ENOMEM;
  38	return 0;
  39}
  40
  41void __cold btrfs_delayed_inode_exit(void)
  42{
  43	kmem_cache_destroy(delayed_node_cache);
  44}
  45
  46static inline void btrfs_init_delayed_node(
  47				struct btrfs_delayed_node *delayed_node,
  48				struct btrfs_root *root, u64 inode_id)
  49{
  50	delayed_node->root = root;
  51	delayed_node->inode_id = inode_id;
  52	refcount_set(&delayed_node->refs, 0);
  53	delayed_node->ins_root = RB_ROOT_CACHED;
  54	delayed_node->del_root = RB_ROOT_CACHED;
  55	mutex_init(&delayed_node->mutex);
  56	INIT_LIST_HEAD(&delayed_node->n_list);
  57	INIT_LIST_HEAD(&delayed_node->p_list);
  58}
  59
 
 
 
 
 
 
 
 
 
 
 
 
  60static struct btrfs_delayed_node *btrfs_get_delayed_node(
  61		struct btrfs_inode *btrfs_inode)
  62{
  63	struct btrfs_root *root = btrfs_inode->root;
  64	u64 ino = btrfs_ino(btrfs_inode);
  65	struct btrfs_delayed_node *node;
  66
  67	node = READ_ONCE(btrfs_inode->delayed_node);
  68	if (node) {
  69		refcount_inc(&node->refs);
  70		return node;
  71	}
  72
  73	spin_lock(&root->inode_lock);
  74	node = radix_tree_lookup(&root->delayed_nodes_tree, ino);
  75
  76	if (node) {
  77		if (btrfs_inode->delayed_node) {
  78			refcount_inc(&node->refs);	/* can be accessed */
  79			BUG_ON(btrfs_inode->delayed_node != node);
  80			spin_unlock(&root->inode_lock);
  81			return node;
  82		}
  83
  84		/*
  85		 * It's possible that we're racing into the middle of removing
  86		 * this node from the radix tree.  In this case, the refcount
  87		 * was zero and it should never go back to one.  Just return
  88		 * NULL like it was never in the radix at all; our release
  89		 * function is in the process of removing it.
  90		 *
  91		 * Some implementations of refcount_inc refuse to bump the
  92		 * refcount once it has hit zero.  If we don't do this dance
  93		 * here, refcount_inc() may decide to just WARN_ONCE() instead
  94		 * of actually bumping the refcount.
  95		 *
  96		 * If this node is properly in the radix, we want to bump the
  97		 * refcount twice, once for the inode and once for this get
  98		 * operation.
  99		 */
 100		if (refcount_inc_not_zero(&node->refs)) {
 101			refcount_inc(&node->refs);
 102			btrfs_inode->delayed_node = node;
 103		} else {
 104			node = NULL;
 105		}
 106
 107		spin_unlock(&root->inode_lock);
 108		return node;
 109	}
 110	spin_unlock(&root->inode_lock);
 111
 112	return NULL;
 113}
 114
 115/* Will return either the node or PTR_ERR(-ENOMEM) */
 116static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
 117		struct btrfs_inode *btrfs_inode)
 118{
 119	struct btrfs_delayed_node *node;
 120	struct btrfs_root *root = btrfs_inode->root;
 121	u64 ino = btrfs_ino(btrfs_inode);
 122	int ret;
 123
 124again:
 125	node = btrfs_get_delayed_node(btrfs_inode);
 126	if (node)
 127		return node;
 128
 129	node = kmem_cache_zalloc(delayed_node_cache, GFP_NOFS);
 130	if (!node)
 131		return ERR_PTR(-ENOMEM);
 132	btrfs_init_delayed_node(node, root, ino);
 133
 134	/* cached in the btrfs inode and can be accessed */
 135	refcount_set(&node->refs, 2);
 136
 137	ret = radix_tree_preload(GFP_NOFS);
 138	if (ret) {
 139		kmem_cache_free(delayed_node_cache, node);
 140		return ERR_PTR(ret);
 141	}
 142
 143	spin_lock(&root->inode_lock);
 144	ret = radix_tree_insert(&root->delayed_nodes_tree, ino, node);
 145	if (ret == -EEXIST) {
 146		spin_unlock(&root->inode_lock);
 147		kmem_cache_free(delayed_node_cache, node);
 148		radix_tree_preload_end();
 149		goto again;
 150	}
 151	btrfs_inode->delayed_node = node;
 152	spin_unlock(&root->inode_lock);
 153	radix_tree_preload_end();
 154
 155	return node;
 156}
 157
 158/*
 159 * Call it when holding delayed_node->mutex
 160 *
 161 * If mod = 1, add this node into the prepared list.
 162 */
 163static void btrfs_queue_delayed_node(struct btrfs_delayed_root *root,
 164				     struct btrfs_delayed_node *node,
 165				     int mod)
 166{
 167	spin_lock(&root->lock);
 168	if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 169		if (!list_empty(&node->p_list))
 170			list_move_tail(&node->p_list, &root->prepare_list);
 171		else if (mod)
 172			list_add_tail(&node->p_list, &root->prepare_list);
 173	} else {
 174		list_add_tail(&node->n_list, &root->node_list);
 175		list_add_tail(&node->p_list, &root->prepare_list);
 176		refcount_inc(&node->refs);	/* inserted into list */
 177		root->nodes++;
 178		set_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 179	}
 180	spin_unlock(&root->lock);
 181}
 182
 183/* Call it when holding delayed_node->mutex */
 184static void btrfs_dequeue_delayed_node(struct btrfs_delayed_root *root,
 185				       struct btrfs_delayed_node *node)
 186{
 187	spin_lock(&root->lock);
 188	if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 189		root->nodes--;
 190		refcount_dec(&node->refs);	/* not in the list */
 191		list_del_init(&node->n_list);
 192		if (!list_empty(&node->p_list))
 193			list_del_init(&node->p_list);
 194		clear_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
 195	}
 196	spin_unlock(&root->lock);
 197}
 198
 199static struct btrfs_delayed_node *btrfs_first_delayed_node(
 200			struct btrfs_delayed_root *delayed_root)
 201{
 202	struct list_head *p;
 203	struct btrfs_delayed_node *node = NULL;
 204
 205	spin_lock(&delayed_root->lock);
 206	if (list_empty(&delayed_root->node_list))
 207		goto out;
 208
 209	p = delayed_root->node_list.next;
 210	node = list_entry(p, struct btrfs_delayed_node, n_list);
 211	refcount_inc(&node->refs);
 212out:
 213	spin_unlock(&delayed_root->lock);
 214
 215	return node;
 216}
 217
 218static struct btrfs_delayed_node *btrfs_next_delayed_node(
 219						struct btrfs_delayed_node *node)
 220{
 221	struct btrfs_delayed_root *delayed_root;
 222	struct list_head *p;
 223	struct btrfs_delayed_node *next = NULL;
 224
 225	delayed_root = node->root->fs_info->delayed_root;
 226	spin_lock(&delayed_root->lock);
 227	if (!test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
 228		/* not in the list */
 229		if (list_empty(&delayed_root->node_list))
 230			goto out;
 231		p = delayed_root->node_list.next;
 232	} else if (list_is_last(&node->n_list, &delayed_root->node_list))
 233		goto out;
 234	else
 235		p = node->n_list.next;
 236
 237	next = list_entry(p, struct btrfs_delayed_node, n_list);
 238	refcount_inc(&next->refs);
 239out:
 240	spin_unlock(&delayed_root->lock);
 241
 242	return next;
 243}
 244
 245static void __btrfs_release_delayed_node(
 246				struct btrfs_delayed_node *delayed_node,
 247				int mod)
 248{
 249	struct btrfs_delayed_root *delayed_root;
 250
 251	if (!delayed_node)
 252		return;
 253
 254	delayed_root = delayed_node->root->fs_info->delayed_root;
 255
 256	mutex_lock(&delayed_node->mutex);
 257	if (delayed_node->count)
 258		btrfs_queue_delayed_node(delayed_root, delayed_node, mod);
 259	else
 260		btrfs_dequeue_delayed_node(delayed_root, delayed_node);
 261	mutex_unlock(&delayed_node->mutex);
 262
 263	if (refcount_dec_and_test(&delayed_node->refs)) {
 264		struct btrfs_root *root = delayed_node->root;
 265
 266		spin_lock(&root->inode_lock);
 267		/*
 268		 * Once our refcount goes to zero, nobody is allowed to bump it
 269		 * back up.  We can delete it now.
 270		 */
 271		ASSERT(refcount_read(&delayed_node->refs) == 0);
 272		radix_tree_delete(&root->delayed_nodes_tree,
 273				  delayed_node->inode_id);
 274		spin_unlock(&root->inode_lock);
 275		kmem_cache_free(delayed_node_cache, delayed_node);
 276	}
 277}
 278
 279static inline void btrfs_release_delayed_node(struct btrfs_delayed_node *node)
 280{
 281	__btrfs_release_delayed_node(node, 0);
 282}
 283
 284static struct btrfs_delayed_node *btrfs_first_prepared_delayed_node(
 285					struct btrfs_delayed_root *delayed_root)
 286{
 287	struct list_head *p;
 288	struct btrfs_delayed_node *node = NULL;
 289
 290	spin_lock(&delayed_root->lock);
 291	if (list_empty(&delayed_root->prepare_list))
 292		goto out;
 293
 294	p = delayed_root->prepare_list.next;
 295	list_del_init(p);
 296	node = list_entry(p, struct btrfs_delayed_node, p_list);
 297	refcount_inc(&node->refs);
 298out:
 299	spin_unlock(&delayed_root->lock);
 300
 301	return node;
 302}
 303
 304static inline void btrfs_release_prepared_delayed_node(
 305					struct btrfs_delayed_node *node)
 306{
 307	__btrfs_release_delayed_node(node, 1);
 308}
 309
 310static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u16 data_len,
 311					   struct btrfs_delayed_node *node,
 312					   enum btrfs_delayed_item_type type)
 313{
 314	struct btrfs_delayed_item *item;
 315
 316	item = kmalloc(sizeof(*item) + data_len, GFP_NOFS);
 317	if (item) {
 318		item->data_len = data_len;
 319		item->type = type;
 320		item->bytes_reserved = 0;
 321		item->delayed_node = node;
 322		RB_CLEAR_NODE(&item->rb_node);
 323		INIT_LIST_HEAD(&item->log_list);
 324		item->logged = false;
 325		refcount_set(&item->refs, 1);
 326	}
 327	return item;
 328}
 329
 330/*
 331 * __btrfs_lookup_delayed_item - look up the delayed item by key
 332 * @delayed_node: pointer to the delayed node
 333 * @index:	  the dir index value to lookup (offset of a dir index key)
 
 
 334 *
 335 * Note: if we don't find the right item, we will return the prev item and
 336 * the next item.
 337 */
 338static struct btrfs_delayed_item *__btrfs_lookup_delayed_item(
 339				struct rb_root *root,
 340				u64 index)
 
 
 341{
 342	struct rb_node *node = root->rb_node;
 343	struct btrfs_delayed_item *delayed_item = NULL;
 
 
 
 344
 345	while (node) {
 346		delayed_item = rb_entry(node, struct btrfs_delayed_item,
 347					rb_node);
 348		if (delayed_item->index < index)
 
 
 349			node = node->rb_right;
 350		else if (delayed_item->index > index)
 351			node = node->rb_left;
 352		else
 353			return delayed_item;
 354	}
 355
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 356	return NULL;
 357}
 358
 
 
 
 
 
 
 
 
 359static int __btrfs_add_delayed_item(struct btrfs_delayed_node *delayed_node,
 360				    struct btrfs_delayed_item *ins)
 
 361{
 362	struct rb_node **p, *node;
 363	struct rb_node *parent_node = NULL;
 364	struct rb_root_cached *root;
 365	struct btrfs_delayed_item *item;
 366	bool leftmost = true;
 367
 368	if (ins->type == BTRFS_DELAYED_INSERTION_ITEM)
 369		root = &delayed_node->ins_root;
 370	else
 371		root = &delayed_node->del_root;
 372
 373	p = &root->rb_root.rb_node;
 
 374	node = &ins->rb_node;
 375
 376	while (*p) {
 377		parent_node = *p;
 378		item = rb_entry(parent_node, struct btrfs_delayed_item,
 379				 rb_node);
 380
 381		if (item->index < ins->index) {
 
 382			p = &(*p)->rb_right;
 383			leftmost = false;
 384		} else if (item->index > ins->index) {
 385			p = &(*p)->rb_left;
 386		} else {
 387			return -EEXIST;
 388		}
 389	}
 390
 391	rb_link_node(node, parent_node, p);
 392	rb_insert_color_cached(node, root, leftmost);
 393
 394	if (ins->type == BTRFS_DELAYED_INSERTION_ITEM &&
 395	    ins->index >= delayed_node->index_cnt)
 396		delayed_node->index_cnt = ins->index + 1;
 
 
 
 397
 398	delayed_node->count++;
 399	atomic_inc(&delayed_node->root->fs_info->delayed_root->items);
 400	return 0;
 401}
 402
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 403static void finish_one_item(struct btrfs_delayed_root *delayed_root)
 404{
 405	int seq = atomic_inc_return(&delayed_root->items_seq);
 406
 407	/* atomic_dec_return implies a barrier */
 
 
 408	if ((atomic_dec_return(&delayed_root->items) <
 409	    BTRFS_DELAYED_BACKGROUND || seq % BTRFS_DELAYED_BATCH == 0))
 410		cond_wake_up_nomb(&delayed_root->wait);
 
 411}
 412
 413static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item)
 414{
 415	struct rb_root_cached *root;
 416	struct btrfs_delayed_root *delayed_root;
 417
 418	/* Not inserted, ignore it. */
 419	if (RB_EMPTY_NODE(&delayed_item->rb_node))
 420		return;
 421
 422	delayed_root = delayed_item->delayed_node->root->fs_info->delayed_root;
 423
 424	BUG_ON(!delayed_root);
 
 
 425
 426	if (delayed_item->type == BTRFS_DELAYED_INSERTION_ITEM)
 427		root = &delayed_item->delayed_node->ins_root;
 428	else
 429		root = &delayed_item->delayed_node->del_root;
 430
 431	rb_erase_cached(&delayed_item->rb_node, root);
 432	RB_CLEAR_NODE(&delayed_item->rb_node);
 433	delayed_item->delayed_node->count--;
 434
 435	finish_one_item(delayed_root);
 436}
 437
 438static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
 439{
 440	if (item) {
 441		__btrfs_remove_delayed_item(item);
 442		if (refcount_dec_and_test(&item->refs))
 443			kfree(item);
 444	}
 445}
 446
 447static struct btrfs_delayed_item *__btrfs_first_delayed_insertion_item(
 448					struct btrfs_delayed_node *delayed_node)
 449{
 450	struct rb_node *p;
 451	struct btrfs_delayed_item *item = NULL;
 452
 453	p = rb_first_cached(&delayed_node->ins_root);
 454	if (p)
 455		item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 456
 457	return item;
 458}
 459
 460static struct btrfs_delayed_item *__btrfs_first_delayed_deletion_item(
 461					struct btrfs_delayed_node *delayed_node)
 462{
 463	struct rb_node *p;
 464	struct btrfs_delayed_item *item = NULL;
 465
 466	p = rb_first_cached(&delayed_node->del_root);
 467	if (p)
 468		item = rb_entry(p, struct btrfs_delayed_item, rb_node);
 469
 470	return item;
 471}
 472
 473static struct btrfs_delayed_item *__btrfs_next_delayed_item(
 474						struct btrfs_delayed_item *item)
 475{
 476	struct rb_node *p;
 477	struct btrfs_delayed_item *next = NULL;
 478
 479	p = rb_next(&item->rb_node);
 480	if (p)
 481		next = rb_entry(p, struct btrfs_delayed_item, rb_node);
 482
 483	return next;
 484}
 485
 486static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
 
 487					       struct btrfs_delayed_item *item)
 488{
 489	struct btrfs_block_rsv *src_rsv;
 490	struct btrfs_block_rsv *dst_rsv;
 491	struct btrfs_fs_info *fs_info = trans->fs_info;
 492	u64 num_bytes;
 493	int ret;
 494
 495	if (!trans->bytes_reserved)
 496		return 0;
 497
 498	src_rsv = trans->block_rsv;
 499	dst_rsv = &fs_info->delayed_block_rsv;
 500
 501	num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
 502
 503	/*
 504	 * Here we migrate space rsv from transaction rsv, since have already
 505	 * reserved space when starting a transaction.  So no need to reserve
 506	 * qgroup space here.
 507	 */
 508	ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 509	if (!ret) {
 510		trace_btrfs_space_reservation(fs_info, "delayed_item",
 511					      item->delayed_node->inode_id,
 512					      num_bytes, 1);
 513		/*
 514		 * For insertions we track reserved metadata space by accounting
 515		 * for the number of leaves that will be used, based on the delayed
 516		 * node's index_items_size field.
 517		 */
 518		if (item->type == BTRFS_DELAYED_DELETION_ITEM)
 519			item->bytes_reserved = num_bytes;
 520	}
 521
 522	return ret;
 523}
 524
 525static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
 526						struct btrfs_delayed_item *item)
 527{
 528	struct btrfs_block_rsv *rsv;
 529	struct btrfs_fs_info *fs_info = root->fs_info;
 530
 531	if (!item->bytes_reserved)
 532		return;
 533
 534	rsv = &fs_info->delayed_block_rsv;
 535	/*
 536	 * Check btrfs_delayed_item_reserve_metadata() to see why we don't need
 537	 * to release/reserve qgroup space.
 538	 */
 539	trace_btrfs_space_reservation(fs_info, "delayed_item",
 540				      item->delayed_node->inode_id,
 541				      item->bytes_reserved, 0);
 542	btrfs_block_rsv_release(fs_info, rsv, item->bytes_reserved, NULL);
 543}
 544
 545static void btrfs_delayed_item_release_leaves(struct btrfs_delayed_node *node,
 546					      unsigned int num_leaves)
 547{
 548	struct btrfs_fs_info *fs_info = node->root->fs_info;
 549	const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, num_leaves);
 550
 551	/* There are no space reservations during log replay, bail out. */
 552	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
 553		return;
 554
 555	trace_btrfs_space_reservation(fs_info, "delayed_item", node->inode_id,
 556				      bytes, 0);
 557	btrfs_block_rsv_release(fs_info, &fs_info->delayed_block_rsv, bytes, NULL);
 558}
 559
 560static int btrfs_delayed_inode_reserve_metadata(
 561					struct btrfs_trans_handle *trans,
 562					struct btrfs_root *root,
 
 563					struct btrfs_delayed_node *node)
 564{
 565	struct btrfs_fs_info *fs_info = root->fs_info;
 566	struct btrfs_block_rsv *src_rsv;
 567	struct btrfs_block_rsv *dst_rsv;
 568	u64 num_bytes;
 569	int ret;
 570
 571	src_rsv = trans->block_rsv;
 572	dst_rsv = &fs_info->delayed_block_rsv;
 573
 574	num_bytes = btrfs_calc_metadata_size(fs_info, 1);
 575
 576	/*
 577	 * btrfs_dirty_inode will update the inode under btrfs_join_transaction
 578	 * which doesn't reserve space for speed.  This is a problem since we
 579	 * still need to reserve space for this update, so try to reserve the
 580	 * space.
 581	 *
 582	 * Now if src_rsv == delalloc_block_rsv we'll let it just steal since
 583	 * we always reserve enough to update the inode item.
 584	 */
 585	if (!src_rsv || (!trans->bytes_reserved &&
 586			 src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) {
 587		ret = btrfs_qgroup_reserve_meta(root, num_bytes,
 588					  BTRFS_QGROUP_RSV_META_PREALLOC, true);
 589		if (ret < 0)
 590			return ret;
 591		ret = btrfs_block_rsv_add(fs_info, dst_rsv, num_bytes,
 592					  BTRFS_RESERVE_NO_FLUSH);
 593		/* NO_FLUSH could only fail with -ENOSPC */
 594		ASSERT(ret == 0 || ret == -ENOSPC);
 595		if (ret)
 
 
 
 
 
 596			btrfs_qgroup_free_meta_prealloc(root, num_bytes);
 597	} else {
 598		ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
 
 
 
 
 
 
 
 
 
 599	}
 600
 
 601	if (!ret) {
 602		trace_btrfs_space_reservation(fs_info, "delayed_inode",
 603					      node->inode_id, num_bytes, 1);
 604		node->bytes_reserved = num_bytes;
 605	}
 606
 607	return ret;
 608}
 609
 610static void btrfs_delayed_inode_release_metadata(struct btrfs_fs_info *fs_info,
 611						struct btrfs_delayed_node *node,
 612						bool qgroup_free)
 613{
 614	struct btrfs_block_rsv *rsv;
 615
 616	if (!node->bytes_reserved)
 617		return;
 618
 619	rsv = &fs_info->delayed_block_rsv;
 620	trace_btrfs_space_reservation(fs_info, "delayed_inode",
 621				      node->inode_id, node->bytes_reserved, 0);
 622	btrfs_block_rsv_release(fs_info, rsv, node->bytes_reserved, NULL);
 
 623	if (qgroup_free)
 624		btrfs_qgroup_free_meta_prealloc(node->root,
 625				node->bytes_reserved);
 626	else
 627		btrfs_qgroup_convert_reserved_meta(node->root,
 628				node->bytes_reserved);
 629	node->bytes_reserved = 0;
 630}
 631
 632/*
 633 * Insert a single delayed item or a batch of delayed items, as many as possible
 634 * that fit in a leaf. The delayed items (dir index keys) are sorted by their key
 635 * in the rbtree, and if there's a gap between two consecutive dir index items,
 636 * then it means at some point we had delayed dir indexes to add but they got
 637 * removed (by btrfs_delete_delayed_dir_index()) before we attempted to flush them
 638 * into the subvolume tree. Dir index keys also have their offsets coming from a
 639 * monotonically increasing counter, so we can't get new keys with an offset that
 640 * fits within a gap between delayed dir index items.
 641 */
 642static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 643				     struct btrfs_root *root,
 644				     struct btrfs_path *path,
 645				     struct btrfs_delayed_item *first_item)
 646{
 647	struct btrfs_fs_info *fs_info = root->fs_info;
 648	struct btrfs_delayed_node *node = first_item->delayed_node;
 649	LIST_HEAD(item_list);
 650	struct btrfs_delayed_item *curr;
 651	struct btrfs_delayed_item *next;
 652	const int max_size = BTRFS_LEAF_DATA_SIZE(fs_info);
 653	struct btrfs_item_batch batch;
 654	struct btrfs_key first_key;
 655	const u32 first_data_size = first_item->data_len;
 656	int total_size;
 657	char *ins_data = NULL;
 658	int ret;
 659	bool continuous_keys_only = false;
 660
 661	lockdep_assert_held(&node->mutex);
 662
 663	/*
 664	 * During normal operation the delayed index offset is continuously
 665	 * increasing, so we can batch insert all items as there will not be any
 666	 * overlapping keys in the tree.
 667	 *
 668	 * The exception to this is log replay, where we may have interleaved
 669	 * offsets in the tree, so our batch needs to be continuous keys only in
 670	 * order to ensure we do not end up with out of order items in our leaf.
 671	 */
 672	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
 673		continuous_keys_only = true;
 674
 675	/*
 676	 * For delayed items to insert, we track reserved metadata bytes based
 677	 * on the number of leaves that we will use.
 678	 * See btrfs_insert_delayed_dir_index() and
 679	 * btrfs_delayed_item_reserve_metadata()).
 680	 */
 681	ASSERT(first_item->bytes_reserved == 0);
 682
 683	list_add_tail(&first_item->tree_list, &item_list);
 684	batch.total_data_size = first_data_size;
 685	batch.nr = 1;
 686	total_size = first_data_size + sizeof(struct btrfs_item);
 687	curr = first_item;
 688
 689	while (true) {
 690		int next_size;
 691
 
 692		next = __btrfs_next_delayed_item(curr);
 693		if (!next)
 694			break;
 695
 696		/*
 697		 * We cannot allow gaps in the key space if we're doing log
 698		 * replay.
 699		 */
 700		if (continuous_keys_only && (next->index != curr->index + 1))
 701			break;
 702
 703		ASSERT(next->bytes_reserved == 0);
 704
 705		next_size = next->data_len + sizeof(struct btrfs_item);
 706		if (total_size + next_size > max_size)
 707			break;
 708
 709		list_add_tail(&next->tree_list, &item_list);
 710		batch.nr++;
 711		total_size += next_size;
 712		batch.total_data_size += next->data_len;
 713		curr = next;
 714	}
 715
 716	if (batch.nr == 1) {
 717		first_key.objectid = node->inode_id;
 718		first_key.type = BTRFS_DIR_INDEX_KEY;
 719		first_key.offset = first_item->index;
 720		batch.keys = &first_key;
 721		batch.data_sizes = &first_data_size;
 722	} else {
 723		struct btrfs_key *ins_keys;
 724		u32 *ins_sizes;
 725		int i = 0;
 726
 727		ins_data = kmalloc(batch.nr * sizeof(u32) +
 728				   batch.nr * sizeof(struct btrfs_key), GFP_NOFS);
 729		if (!ins_data) {
 730			ret = -ENOMEM;
 731			goto out;
 732		}
 733		ins_sizes = (u32 *)ins_data;
 734		ins_keys = (struct btrfs_key *)(ins_data + batch.nr * sizeof(u32));
 735		batch.keys = ins_keys;
 736		batch.data_sizes = ins_sizes;
 737		list_for_each_entry(curr, &item_list, tree_list) {
 738			ins_keys[i].objectid = node->inode_id;
 739			ins_keys[i].type = BTRFS_DIR_INDEX_KEY;
 740			ins_keys[i].offset = curr->index;
 741			ins_sizes[i] = curr->data_len;
 742			i++;
 743		}
 744	}
 745
 746	ret = btrfs_insert_empty_items(trans, root, path, &batch);
 747	if (ret)
 
 
 
 
 
 
 
 
 748		goto out;
 
 749
 750	list_for_each_entry(curr, &item_list, tree_list) {
 751		char *data_ptr;
 
 
 
 752
 753		data_ptr = btrfs_item_ptr(path->nodes[0], path->slots[0], char);
 754		write_extent_buffer(path->nodes[0], &curr->data,
 755				    (unsigned long)data_ptr, curr->data_len);
 756		path->slots[0]++;
 
 
 757	}
 758
 759	/*
 760	 * Now release our path before releasing the delayed items and their
 761	 * metadata reservations, so that we don't block other tasks for more
 762	 * time than needed.
 763	 */
 764	btrfs_release_path(path);
 765
 766	ASSERT(node->index_item_leaves > 0);
 
 
 767
 768	/*
 769	 * For normal operations we will batch an entire leaf's worth of delayed
 770	 * items, so if there are more items to process we can decrement
 771	 * index_item_leaves by 1 as we inserted 1 leaf's worth of items.
 772	 *
 773	 * However for log replay we may not have inserted an entire leaf's
 774	 * worth of items, we may have not had continuous items, so decrementing
 775	 * here would mess up the index_item_leaves accounting.  For this case
 776	 * only clean up the accounting when there are no items left.
 777	 */
 778	if (next && !continuous_keys_only) {
 779		/*
 780		 * We inserted one batch of items into a leaf a there are more
 781		 * items to flush in a future batch, now release one unit of
 782		 * metadata space from the delayed block reserve, corresponding
 783		 * the leaf we just flushed to.
 784		 */
 785		btrfs_delayed_item_release_leaves(node, 1);
 786		node->index_item_leaves--;
 787	} else if (!next) {
 788		/*
 789		 * There are no more items to insert. We can have a number of
 790		 * reserved leaves > 1 here - this happens when many dir index
 791		 * items are added and then removed before they are flushed (file
 792		 * names with a very short life, never span a transaction). So
 793		 * release all remaining leaves.
 794		 */
 795		btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
 796		node->index_item_leaves = 0;
 797	}
 798
 799	list_for_each_entry_safe(curr, next, &item_list, tree_list) {
 800		list_del(&curr->tree_list);
 801		btrfs_release_delayed_item(curr);
 802	}
 
 
 
 
 803out:
 804	kfree(ins_data);
 805	return ret;
 806}
 807
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 808static int btrfs_insert_delayed_items(struct btrfs_trans_handle *trans,
 809				      struct btrfs_path *path,
 810				      struct btrfs_root *root,
 811				      struct btrfs_delayed_node *node)
 812{
 
 813	int ret = 0;
 814
 815	while (ret == 0) {
 816		struct btrfs_delayed_item *curr;
 
 
 
 817
 818		mutex_lock(&node->mutex);
 819		curr = __btrfs_first_delayed_insertion_item(node);
 820		if (!curr) {
 821			mutex_unlock(&node->mutex);
 822			break;
 823		}
 824		ret = btrfs_insert_delayed_item(trans, root, path, curr);
 825		mutex_unlock(&node->mutex);
 
 
 
 
 826	}
 
 
 827
 
 
 
 
 
 
 828	return ret;
 829}
 830
 831static int btrfs_batch_delete_items(struct btrfs_trans_handle *trans,
 832				    struct btrfs_root *root,
 833				    struct btrfs_path *path,
 834				    struct btrfs_delayed_item *item)
 835{
 836	const u64 ino = item->delayed_node->inode_id;
 837	struct btrfs_fs_info *fs_info = root->fs_info;
 838	struct btrfs_delayed_item *curr, *next;
 839	struct extent_buffer *leaf = path->nodes[0];
 840	LIST_HEAD(batch_list);
 841	int nitems, slot, last_slot;
 842	int ret;
 843	u64 total_reserved_size = item->bytes_reserved;
 844
 845	ASSERT(leaf != NULL);
 846
 847	slot = path->slots[0];
 848	last_slot = btrfs_header_nritems(leaf) - 1;
 849	/*
 850	 * Our caller always gives us a path pointing to an existing item, so
 851	 * this can not happen.
 852	 */
 853	ASSERT(slot <= last_slot);
 854	if (WARN_ON(slot > last_slot))
 855		return -ENOENT;
 856
 857	nitems = 1;
 858	curr = item;
 859	list_add_tail(&curr->tree_list, &batch_list);
 860
 
 
 
 
 
 
 
 
 
 861	/*
 862	 * Keep checking if the next delayed item matches the next item in the
 863	 * leaf - if so, we can add it to the batch of items to delete from the
 864	 * leaf.
 865	 */
 866	while (slot < last_slot) {
 867		struct btrfs_key key;
 
 868
 
 869		next = __btrfs_next_delayed_item(curr);
 870		if (!next)
 871			break;
 872
 873		slot++;
 874		btrfs_item_key_to_cpu(leaf, &key, slot);
 875		if (key.objectid != ino ||
 876		    key.type != BTRFS_DIR_INDEX_KEY ||
 877		    key.offset != next->index)
 878			break;
 879		nitems++;
 880		curr = next;
 881		list_add_tail(&curr->tree_list, &batch_list);
 882		total_reserved_size += curr->bytes_reserved;
 
 883	}
 884
 
 
 
 885	ret = btrfs_del_items(trans, root, path, path->slots[0], nitems);
 886	if (ret)
 887		return ret;
 888
 889	/* In case of BTRFS_FS_LOG_RECOVERING items won't have reserved space */
 890	if (total_reserved_size > 0) {
 891		/*
 892		 * Check btrfs_delayed_item_reserve_metadata() to see why we
 893		 * don't need to release/reserve qgroup space.
 894		 */
 895		trace_btrfs_space_reservation(fs_info, "delayed_item", ino,
 896					      total_reserved_size, 0);
 897		btrfs_block_rsv_release(fs_info, &fs_info->delayed_block_rsv,
 898					total_reserved_size, NULL);
 899	}
 900
 901	list_for_each_entry_safe(curr, next, &batch_list, tree_list) {
 
 902		list_del(&curr->tree_list);
 903		btrfs_release_delayed_item(curr);
 904	}
 905
 906	return 0;
 
 907}
 908
 909static int btrfs_delete_delayed_items(struct btrfs_trans_handle *trans,
 910				      struct btrfs_path *path,
 911				      struct btrfs_root *root,
 912				      struct btrfs_delayed_node *node)
 913{
 914	struct btrfs_key key;
 915	int ret = 0;
 916
 917	key.objectid = node->inode_id;
 918	key.type = BTRFS_DIR_INDEX_KEY;
 919
 920	while (ret == 0) {
 921		struct btrfs_delayed_item *item;
 922
 923		mutex_lock(&node->mutex);
 924		item = __btrfs_first_delayed_deletion_item(node);
 925		if (!item) {
 926			mutex_unlock(&node->mutex);
 927			break;
 928		}
 929
 930		key.offset = item->index;
 931		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 932		if (ret > 0) {
 933			/*
 934			 * There's no matching item in the leaf. This means we
 935			 * have already deleted this item in a past run of the
 936			 * delayed items. We ignore errors when running delayed
 937			 * items from an async context, through a work queue job
 938			 * running btrfs_async_run_delayed_root(), and don't
 939			 * release delayed items that failed to complete. This
 940			 * is because we will retry later, and at transaction
 941			 * commit time we always run delayed items and will
 942			 * then deal with errors if they fail to run again.
 943			 *
 944			 * So just release delayed items for which we can't find
 945			 * an item in the tree, and move to the next item.
 946			 */
 947			btrfs_release_path(path);
 948			btrfs_release_delayed_item(item);
 949			ret = 0;
 950		} else if (ret == 0) {
 951			ret = btrfs_batch_delete_items(trans, root, path, item);
 952			btrfs_release_path(path);
 953		}
 954
 
 
 
 
 955		/*
 956		 * We unlock and relock on each iteration, this is to prevent
 957		 * blocking other tasks for too long while we are being run from
 958		 * the async context (work queue job). Those tasks are typically
 959		 * running system calls like creat/mkdir/rename/unlink/etc which
 960		 * need to add delayed items to this delayed node.
 961		 */
 962		mutex_unlock(&node->mutex);
 
 
 
 
 
 
 
 
 
 963	}
 964
 
 
 
 
 
 
 
 
 965	return ret;
 966}
 967
 968static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
 969{
 970	struct btrfs_delayed_root *delayed_root;
 971
 972	if (delayed_node &&
 973	    test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
 974		BUG_ON(!delayed_node->root);
 975		clear_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
 976		delayed_node->count--;
 977
 978		delayed_root = delayed_node->root->fs_info->delayed_root;
 979		finish_one_item(delayed_root);
 980	}
 981}
 982
 983static void btrfs_release_delayed_iref(struct btrfs_delayed_node *delayed_node)
 984{
 
 985
 986	if (test_and_clear_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags)) {
 987		struct btrfs_delayed_root *delayed_root;
 988
 989		ASSERT(delayed_node->root);
 990		delayed_node->count--;
 991
 992		delayed_root = delayed_node->root->fs_info->delayed_root;
 993		finish_one_item(delayed_root);
 994	}
 995}
 996
 997static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
 998					struct btrfs_root *root,
 999					struct btrfs_path *path,
1000					struct btrfs_delayed_node *node)
1001{
1002	struct btrfs_fs_info *fs_info = root->fs_info;
1003	struct btrfs_key key;
1004	struct btrfs_inode_item *inode_item;
1005	struct extent_buffer *leaf;
1006	int mod;
1007	int ret;
1008
1009	key.objectid = node->inode_id;
1010	key.type = BTRFS_INODE_ITEM_KEY;
1011	key.offset = 0;
1012
1013	if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
1014		mod = -1;
1015	else
1016		mod = 1;
1017
1018	ret = btrfs_lookup_inode(trans, root, path, &key, mod);
1019	if (ret > 0)
1020		ret = -ENOENT;
1021	if (ret < 0)
1022		goto out;
 
 
1023
1024	leaf = path->nodes[0];
1025	inode_item = btrfs_item_ptr(leaf, path->slots[0],
1026				    struct btrfs_inode_item);
1027	write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
1028			    sizeof(struct btrfs_inode_item));
1029	btrfs_mark_buffer_dirty(leaf);
1030
1031	if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
1032		goto out;
1033
1034	path->slots[0]++;
1035	if (path->slots[0] >= btrfs_header_nritems(leaf))
1036		goto search;
1037again:
1038	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1039	if (key.objectid != node->inode_id)
1040		goto out;
1041
1042	if (key.type != BTRFS_INODE_REF_KEY &&
1043	    key.type != BTRFS_INODE_EXTREF_KEY)
1044		goto out;
1045
1046	/*
1047	 * Delayed iref deletion is for the inode who has only one link,
1048	 * so there is only one iref. The case that several irefs are
1049	 * in the same item doesn't exist.
1050	 */
1051	btrfs_del_item(trans, root, path);
1052out:
1053	btrfs_release_delayed_iref(node);
 
1054	btrfs_release_path(path);
1055err_out:
1056	btrfs_delayed_inode_release_metadata(fs_info, node, (ret < 0));
1057	btrfs_release_delayed_inode(node);
1058
1059	/*
1060	 * If we fail to update the delayed inode we need to abort the
1061	 * transaction, because we could leave the inode with the improper
1062	 * counts behind.
1063	 */
1064	if (ret && ret != -ENOENT)
1065		btrfs_abort_transaction(trans, ret);
1066
1067	return ret;
1068
1069search:
1070	btrfs_release_path(path);
1071
1072	key.type = BTRFS_INODE_EXTREF_KEY;
1073	key.offset = -1;
1074
1075	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1076	if (ret < 0)
1077		goto err_out;
1078	ASSERT(ret);
1079
1080	ret = 0;
1081	leaf = path->nodes[0];
1082	path->slots[0]--;
1083	goto again;
1084}
1085
1086static inline int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
1087					     struct btrfs_root *root,
1088					     struct btrfs_path *path,
1089					     struct btrfs_delayed_node *node)
1090{
1091	int ret;
1092
1093	mutex_lock(&node->mutex);
1094	if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &node->flags)) {
1095		mutex_unlock(&node->mutex);
1096		return 0;
1097	}
1098
1099	ret = __btrfs_update_delayed_inode(trans, root, path, node);
1100	mutex_unlock(&node->mutex);
1101	return ret;
1102}
1103
1104static inline int
1105__btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1106				   struct btrfs_path *path,
1107				   struct btrfs_delayed_node *node)
1108{
1109	int ret;
1110
1111	ret = btrfs_insert_delayed_items(trans, path, node->root, node);
1112	if (ret)
1113		return ret;
1114
1115	ret = btrfs_delete_delayed_items(trans, path, node->root, node);
1116	if (ret)
1117		return ret;
1118
1119	ret = btrfs_update_delayed_inode(trans, node->root, path, node);
1120	return ret;
1121}
1122
1123/*
1124 * Called when committing the transaction.
1125 * Returns 0 on success.
1126 * Returns < 0 on error and returns with an aborted transaction with any
1127 * outstanding delayed items cleaned up.
1128 */
1129static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
1130{
1131	struct btrfs_fs_info *fs_info = trans->fs_info;
1132	struct btrfs_delayed_root *delayed_root;
1133	struct btrfs_delayed_node *curr_node, *prev_node;
1134	struct btrfs_path *path;
1135	struct btrfs_block_rsv *block_rsv;
1136	int ret = 0;
1137	bool count = (nr > 0);
1138
1139	if (TRANS_ABORTED(trans))
1140		return -EIO;
1141
1142	path = btrfs_alloc_path();
1143	if (!path)
1144		return -ENOMEM;
 
1145
1146	block_rsv = trans->block_rsv;
1147	trans->block_rsv = &fs_info->delayed_block_rsv;
1148
1149	delayed_root = fs_info->delayed_root;
1150
1151	curr_node = btrfs_first_delayed_node(delayed_root);
1152	while (curr_node && (!count || nr--)) {
1153		ret = __btrfs_commit_inode_delayed_items(trans, path,
1154							 curr_node);
1155		if (ret) {
1156			btrfs_release_delayed_node(curr_node);
1157			curr_node = NULL;
1158			btrfs_abort_transaction(trans, ret);
1159			break;
1160		}
1161
1162		prev_node = curr_node;
1163		curr_node = btrfs_next_delayed_node(curr_node);
1164		btrfs_release_delayed_node(prev_node);
1165	}
1166
1167	if (curr_node)
1168		btrfs_release_delayed_node(curr_node);
1169	btrfs_free_path(path);
1170	trans->block_rsv = block_rsv;
1171
1172	return ret;
1173}
1174
1175int btrfs_run_delayed_items(struct btrfs_trans_handle *trans)
1176{
1177	return __btrfs_run_delayed_items(trans, -1);
1178}
1179
1180int btrfs_run_delayed_items_nr(struct btrfs_trans_handle *trans, int nr)
1181{
1182	return __btrfs_run_delayed_items(trans, nr);
1183}
1184
1185int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
1186				     struct btrfs_inode *inode)
1187{
1188	struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1189	struct btrfs_path *path;
1190	struct btrfs_block_rsv *block_rsv;
1191	int ret;
1192
1193	if (!delayed_node)
1194		return 0;
1195
1196	mutex_lock(&delayed_node->mutex);
1197	if (!delayed_node->count) {
1198		mutex_unlock(&delayed_node->mutex);
1199		btrfs_release_delayed_node(delayed_node);
1200		return 0;
1201	}
1202	mutex_unlock(&delayed_node->mutex);
1203
1204	path = btrfs_alloc_path();
1205	if (!path) {
1206		btrfs_release_delayed_node(delayed_node);
1207		return -ENOMEM;
1208	}
 
1209
1210	block_rsv = trans->block_rsv;
1211	trans->block_rsv = &delayed_node->root->fs_info->delayed_block_rsv;
1212
1213	ret = __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1214
1215	btrfs_release_delayed_node(delayed_node);
1216	btrfs_free_path(path);
1217	trans->block_rsv = block_rsv;
1218
1219	return ret;
1220}
1221
1222int btrfs_commit_inode_delayed_inode(struct btrfs_inode *inode)
1223{
1224	struct btrfs_fs_info *fs_info = inode->root->fs_info;
1225	struct btrfs_trans_handle *trans;
1226	struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1227	struct btrfs_path *path;
1228	struct btrfs_block_rsv *block_rsv;
1229	int ret;
1230
1231	if (!delayed_node)
1232		return 0;
1233
1234	mutex_lock(&delayed_node->mutex);
1235	if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1236		mutex_unlock(&delayed_node->mutex);
1237		btrfs_release_delayed_node(delayed_node);
1238		return 0;
1239	}
1240	mutex_unlock(&delayed_node->mutex);
1241
1242	trans = btrfs_join_transaction(delayed_node->root);
1243	if (IS_ERR(trans)) {
1244		ret = PTR_ERR(trans);
1245		goto out;
1246	}
1247
1248	path = btrfs_alloc_path();
1249	if (!path) {
1250		ret = -ENOMEM;
1251		goto trans_out;
1252	}
 
1253
1254	block_rsv = trans->block_rsv;
1255	trans->block_rsv = &fs_info->delayed_block_rsv;
1256
1257	mutex_lock(&delayed_node->mutex);
1258	if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags))
1259		ret = __btrfs_update_delayed_inode(trans, delayed_node->root,
1260						   path, delayed_node);
1261	else
1262		ret = 0;
1263	mutex_unlock(&delayed_node->mutex);
1264
1265	btrfs_free_path(path);
1266	trans->block_rsv = block_rsv;
1267trans_out:
1268	btrfs_end_transaction(trans);
1269	btrfs_btree_balance_dirty(fs_info);
1270out:
1271	btrfs_release_delayed_node(delayed_node);
1272
1273	return ret;
1274}
1275
1276void btrfs_remove_delayed_node(struct btrfs_inode *inode)
1277{
1278	struct btrfs_delayed_node *delayed_node;
1279
1280	delayed_node = READ_ONCE(inode->delayed_node);
1281	if (!delayed_node)
1282		return;
1283
1284	inode->delayed_node = NULL;
1285	btrfs_release_delayed_node(delayed_node);
1286}
1287
1288struct btrfs_async_delayed_work {
1289	struct btrfs_delayed_root *delayed_root;
1290	int nr;
1291	struct btrfs_work work;
1292};
1293
1294static void btrfs_async_run_delayed_root(struct btrfs_work *work)
1295{
1296	struct btrfs_async_delayed_work *async_work;
1297	struct btrfs_delayed_root *delayed_root;
1298	struct btrfs_trans_handle *trans;
1299	struct btrfs_path *path;
1300	struct btrfs_delayed_node *delayed_node = NULL;
1301	struct btrfs_root *root;
1302	struct btrfs_block_rsv *block_rsv;
1303	int total_done = 0;
1304
1305	async_work = container_of(work, struct btrfs_async_delayed_work, work);
1306	delayed_root = async_work->delayed_root;
1307
1308	path = btrfs_alloc_path();
1309	if (!path)
1310		goto out;
1311
1312	do {
1313		if (atomic_read(&delayed_root->items) <
1314		    BTRFS_DELAYED_BACKGROUND / 2)
1315			break;
1316
1317		delayed_node = btrfs_first_prepared_delayed_node(delayed_root);
1318		if (!delayed_node)
1319			break;
1320
 
1321		root = delayed_node->root;
1322
1323		trans = btrfs_join_transaction(root);
1324		if (IS_ERR(trans)) {
1325			btrfs_release_path(path);
1326			btrfs_release_prepared_delayed_node(delayed_node);
1327			total_done++;
1328			continue;
1329		}
1330
1331		block_rsv = trans->block_rsv;
1332		trans->block_rsv = &root->fs_info->delayed_block_rsv;
1333
1334		__btrfs_commit_inode_delayed_items(trans, path, delayed_node);
1335
1336		trans->block_rsv = block_rsv;
1337		btrfs_end_transaction(trans);
1338		btrfs_btree_balance_dirty_nodelay(root->fs_info);
1339
1340		btrfs_release_path(path);
1341		btrfs_release_prepared_delayed_node(delayed_node);
1342		total_done++;
1343
1344	} while ((async_work->nr == 0 && total_done < BTRFS_DELAYED_WRITEBACK)
1345		 || total_done < async_work->nr);
1346
1347	btrfs_free_path(path);
1348out:
1349	wake_up(&delayed_root->wait);
1350	kfree(async_work);
1351}
1352
1353
1354static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
1355				     struct btrfs_fs_info *fs_info, int nr)
1356{
1357	struct btrfs_async_delayed_work *async_work;
1358
1359	async_work = kmalloc(sizeof(*async_work), GFP_NOFS);
1360	if (!async_work)
1361		return -ENOMEM;
1362
1363	async_work->delayed_root = delayed_root;
1364	btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root, NULL,
1365			NULL);
1366	async_work->nr = nr;
1367
1368	btrfs_queue_work(fs_info->delayed_workers, &async_work->work);
1369	return 0;
1370}
1371
1372void btrfs_assert_delayed_root_empty(struct btrfs_fs_info *fs_info)
1373{
1374	WARN_ON(btrfs_first_delayed_node(fs_info->delayed_root));
1375}
1376
1377static int could_end_wait(struct btrfs_delayed_root *delayed_root, int seq)
1378{
1379	int val = atomic_read(&delayed_root->items_seq);
1380
1381	if (val < seq || val >= seq + BTRFS_DELAYED_BATCH)
1382		return 1;
1383
1384	if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
1385		return 1;
1386
1387	return 0;
1388}
1389
1390void btrfs_balance_delayed_items(struct btrfs_fs_info *fs_info)
1391{
1392	struct btrfs_delayed_root *delayed_root = fs_info->delayed_root;
1393
1394	if ((atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND) ||
1395		btrfs_workqueue_normal_congested(fs_info->delayed_workers))
1396		return;
1397
1398	if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
1399		int seq;
1400		int ret;
1401
1402		seq = atomic_read(&delayed_root->items_seq);
1403
1404		ret = btrfs_wq_run_delayed_node(delayed_root, fs_info, 0);
1405		if (ret)
1406			return;
1407
1408		wait_event_interruptible(delayed_root->wait,
1409					 could_end_wait(delayed_root, seq));
1410		return;
1411	}
1412
1413	btrfs_wq_run_delayed_node(delayed_root, fs_info, BTRFS_DELAYED_BATCH);
1414}
1415
1416/* Will return 0 or -ENOMEM */
1417int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 
1418				   const char *name, int name_len,
1419				   struct btrfs_inode *dir,
1420				   struct btrfs_disk_key *disk_key, u8 flags,
1421				   u64 index)
1422{
1423	struct btrfs_fs_info *fs_info = trans->fs_info;
1424	const unsigned int leaf_data_size = BTRFS_LEAF_DATA_SIZE(fs_info);
1425	struct btrfs_delayed_node *delayed_node;
1426	struct btrfs_delayed_item *delayed_item;
1427	struct btrfs_dir_item *dir_item;
1428	bool reserve_leaf_space;
1429	u32 data_len;
1430	int ret;
1431
1432	delayed_node = btrfs_get_or_create_delayed_node(dir);
1433	if (IS_ERR(delayed_node))
1434		return PTR_ERR(delayed_node);
1435
1436	delayed_item = btrfs_alloc_delayed_item(sizeof(*dir_item) + name_len,
1437						delayed_node,
1438						BTRFS_DELAYED_INSERTION_ITEM);
1439	if (!delayed_item) {
1440		ret = -ENOMEM;
1441		goto release_node;
1442	}
1443
1444	delayed_item->index = index;
 
 
1445
1446	dir_item = (struct btrfs_dir_item *)delayed_item->data;
1447	dir_item->location = *disk_key;
1448	btrfs_set_stack_dir_transid(dir_item, trans->transid);
1449	btrfs_set_stack_dir_data_len(dir_item, 0);
1450	btrfs_set_stack_dir_name_len(dir_item, name_len);
1451	btrfs_set_stack_dir_flags(dir_item, flags);
1452	memcpy((char *)(dir_item + 1), name, name_len);
1453
1454	data_len = delayed_item->data_len + sizeof(struct btrfs_item);
1455
1456	mutex_lock(&delayed_node->mutex);
1457
1458	if (delayed_node->index_item_leaves == 0 ||
1459	    delayed_node->curr_index_batch_size + data_len > leaf_data_size) {
1460		delayed_node->curr_index_batch_size = data_len;
1461		reserve_leaf_space = true;
1462	} else {
1463		delayed_node->curr_index_batch_size += data_len;
1464		reserve_leaf_space = false;
1465	}
1466
1467	if (reserve_leaf_space) {
1468		ret = btrfs_delayed_item_reserve_metadata(trans, delayed_item);
1469		/*
1470		 * Space was reserved for a dir index item insertion when we
1471		 * started the transaction, so getting a failure here should be
1472		 * impossible.
1473		 */
1474		if (WARN_ON(ret)) {
1475			mutex_unlock(&delayed_node->mutex);
1476			btrfs_release_delayed_item(delayed_item);
1477			goto release_node;
1478		}
1479
1480		delayed_node->index_item_leaves++;
1481	} else if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
1482		const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
1483
1484		/*
1485		 * Adding the new dir index item does not require touching another
1486		 * leaf, so we can release 1 unit of metadata that was previously
1487		 * reserved when starting the transaction. This applies only to
1488		 * the case where we had a transaction start and excludes the
1489		 * transaction join case (when replaying log trees).
1490		 */
1491		trace_btrfs_space_reservation(fs_info, "transaction",
1492					      trans->transid, bytes, 0);
1493		btrfs_block_rsv_release(fs_info, trans->block_rsv, bytes, NULL);
1494		ASSERT(trans->bytes_reserved >= bytes);
1495		trans->bytes_reserved -= bytes;
1496	}
1497
1498	ret = __btrfs_add_delayed_item(delayed_node, delayed_item);
 
1499	if (unlikely(ret)) {
1500		btrfs_err(trans->fs_info,
1501			  "err add delayed dir index item(name: %.*s) into the insertion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
1502			  name_len, name, delayed_node->root->root_key.objectid,
1503			  delayed_node->inode_id, ret);
1504		BUG();
1505	}
1506	mutex_unlock(&delayed_node->mutex);
1507
1508release_node:
1509	btrfs_release_delayed_node(delayed_node);
1510	return ret;
1511}
1512
1513static int btrfs_delete_delayed_insertion_item(struct btrfs_fs_info *fs_info,
1514					       struct btrfs_delayed_node *node,
1515					       u64 index)
1516{
1517	struct btrfs_delayed_item *item;
1518
1519	mutex_lock(&node->mutex);
1520	item = __btrfs_lookup_delayed_item(&node->ins_root.rb_root, index);
1521	if (!item) {
1522		mutex_unlock(&node->mutex);
1523		return 1;
1524	}
1525
1526	/*
1527	 * For delayed items to insert, we track reserved metadata bytes based
1528	 * on the number of leaves that we will use.
1529	 * See btrfs_insert_delayed_dir_index() and
1530	 * btrfs_delayed_item_reserve_metadata()).
1531	 */
1532	ASSERT(item->bytes_reserved == 0);
1533	ASSERT(node->index_item_leaves > 0);
1534
1535	/*
1536	 * If there's only one leaf reserved, we can decrement this item from the
1537	 * current batch, otherwise we can not because we don't know which leaf
1538	 * it belongs to. With the current limit on delayed items, we rarely
1539	 * accumulate enough dir index items to fill more than one leaf (even
1540	 * when using a leaf size of 4K).
1541	 */
1542	if (node->index_item_leaves == 1) {
1543		const u32 data_len = item->data_len + sizeof(struct btrfs_item);
1544
1545		ASSERT(node->curr_index_batch_size >= data_len);
1546		node->curr_index_batch_size -= data_len;
1547	}
1548
1549	btrfs_release_delayed_item(item);
1550
1551	/* If we now have no more dir index items, we can release all leaves. */
1552	if (RB_EMPTY_ROOT(&node->ins_root.rb_root)) {
1553		btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
1554		node->index_item_leaves = 0;
1555	}
1556
1557	mutex_unlock(&node->mutex);
1558	return 0;
1559}
1560
1561int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
 
1562				   struct btrfs_inode *dir, u64 index)
1563{
1564	struct btrfs_delayed_node *node;
1565	struct btrfs_delayed_item *item;
 
1566	int ret;
1567
1568	node = btrfs_get_or_create_delayed_node(dir);
1569	if (IS_ERR(node))
1570		return PTR_ERR(node);
1571
1572	ret = btrfs_delete_delayed_insertion_item(trans->fs_info, node, index);
 
 
 
 
1573	if (!ret)
1574		goto end;
1575
1576	item = btrfs_alloc_delayed_item(0, node, BTRFS_DELAYED_DELETION_ITEM);
1577	if (!item) {
1578		ret = -ENOMEM;
1579		goto end;
1580	}
1581
1582	item->index = index;
1583
1584	ret = btrfs_delayed_item_reserve_metadata(trans, item);
1585	/*
1586	 * we have reserved enough space when we start a new transaction,
1587	 * so reserving metadata failure is impossible.
1588	 */
1589	if (ret < 0) {
1590		btrfs_err(trans->fs_info,
1591"metadata reservation failed for delayed dir item deltiona, should have been reserved");
1592		btrfs_release_delayed_item(item);
1593		goto end;
1594	}
1595
1596	mutex_lock(&node->mutex);
1597	ret = __btrfs_add_delayed_item(node, item);
1598	if (unlikely(ret)) {
1599		btrfs_err(trans->fs_info,
1600			  "err add delayed dir index item(index: %llu) into the deletion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
1601			  index, node->root->root_key.objectid,
1602			  node->inode_id, ret);
1603		btrfs_delayed_item_release_metadata(dir->root, item);
1604		btrfs_release_delayed_item(item);
1605	}
1606	mutex_unlock(&node->mutex);
1607end:
1608	btrfs_release_delayed_node(node);
1609	return ret;
1610}
1611
1612int btrfs_inode_delayed_dir_index_count(struct btrfs_inode *inode)
1613{
1614	struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
1615
1616	if (!delayed_node)
1617		return -ENOENT;
1618
1619	/*
1620	 * Since we have held i_mutex of this directory, it is impossible that
1621	 * a new directory index is added into the delayed node and index_cnt
1622	 * is updated now. So we needn't lock the delayed node.
1623	 */
1624	if (!delayed_node->index_cnt) {
1625		btrfs_release_delayed_node(delayed_node);
1626		return -EINVAL;
1627	}
1628
1629	inode->index_cnt = delayed_node->index_cnt;
1630	btrfs_release_delayed_node(delayed_node);
1631	return 0;
1632}
1633
1634bool btrfs_readdir_get_delayed_items(struct inode *inode,
1635				     struct list_head *ins_list,
1636				     struct list_head *del_list)
1637{
1638	struct btrfs_delayed_node *delayed_node;
1639	struct btrfs_delayed_item *item;
1640
1641	delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1642	if (!delayed_node)
1643		return false;
1644
1645	/*
1646	 * We can only do one readdir with delayed items at a time because of
1647	 * item->readdir_list.
1648	 */
1649	btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
1650	btrfs_inode_lock(BTRFS_I(inode), 0);
1651
1652	mutex_lock(&delayed_node->mutex);
1653	item = __btrfs_first_delayed_insertion_item(delayed_node);
1654	while (item) {
1655		refcount_inc(&item->refs);
1656		list_add_tail(&item->readdir_list, ins_list);
1657		item = __btrfs_next_delayed_item(item);
1658	}
1659
1660	item = __btrfs_first_delayed_deletion_item(delayed_node);
1661	while (item) {
1662		refcount_inc(&item->refs);
1663		list_add_tail(&item->readdir_list, del_list);
1664		item = __btrfs_next_delayed_item(item);
1665	}
1666	mutex_unlock(&delayed_node->mutex);
1667	/*
1668	 * This delayed node is still cached in the btrfs inode, so refs
1669	 * must be > 1 now, and we needn't check it is going to be freed
1670	 * or not.
1671	 *
1672	 * Besides that, this function is used to read dir, we do not
1673	 * insert/delete delayed items in this period. So we also needn't
1674	 * requeue or dequeue this delayed node.
1675	 */
1676	refcount_dec(&delayed_node->refs);
1677
1678	return true;
1679}
1680
1681void btrfs_readdir_put_delayed_items(struct inode *inode,
1682				     struct list_head *ins_list,
1683				     struct list_head *del_list)
1684{
1685	struct btrfs_delayed_item *curr, *next;
1686
1687	list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1688		list_del(&curr->readdir_list);
1689		if (refcount_dec_and_test(&curr->refs))
1690			kfree(curr);
1691	}
1692
1693	list_for_each_entry_safe(curr, next, del_list, readdir_list) {
1694		list_del(&curr->readdir_list);
1695		if (refcount_dec_and_test(&curr->refs))
1696			kfree(curr);
1697	}
1698
1699	/*
1700	 * The VFS is going to do up_read(), so we need to downgrade back to a
1701	 * read lock.
1702	 */
1703	downgrade_write(&inode->i_rwsem);
1704}
1705
1706int btrfs_should_delete_dir_index(struct list_head *del_list,
1707				  u64 index)
1708{
1709	struct btrfs_delayed_item *curr;
1710	int ret = 0;
1711
1712	list_for_each_entry(curr, del_list, readdir_list) {
1713		if (curr->index > index)
1714			break;
1715		if (curr->index == index) {
1716			ret = 1;
1717			break;
1718		}
1719	}
1720	return ret;
1721}
1722
1723/*
1724 * btrfs_readdir_delayed_dir_index - read dir info stored in the delayed tree
1725 *
1726 */
1727int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
1728				    struct list_head *ins_list)
1729{
1730	struct btrfs_dir_item *di;
1731	struct btrfs_delayed_item *curr, *next;
1732	struct btrfs_key location;
1733	char *name;
1734	int name_len;
1735	int over = 0;
1736	unsigned char d_type;
1737
1738	if (list_empty(ins_list))
1739		return 0;
1740
1741	/*
1742	 * Changing the data of the delayed item is impossible. So
1743	 * we needn't lock them. And we have held i_mutex of the
1744	 * directory, nobody can delete any directory indexes now.
1745	 */
1746	list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
1747		list_del(&curr->readdir_list);
1748
1749		if (curr->index < ctx->pos) {
1750			if (refcount_dec_and_test(&curr->refs))
1751				kfree(curr);
1752			continue;
1753		}
1754
1755		ctx->pos = curr->index;
1756
1757		di = (struct btrfs_dir_item *)curr->data;
1758		name = (char *)(di + 1);
1759		name_len = btrfs_stack_dir_name_len(di);
1760
1761		d_type = fs_ftype_to_dtype(btrfs_dir_flags_to_ftype(di->type));
1762		btrfs_disk_key_to_cpu(&location, &di->location);
1763
1764		over = !dir_emit(ctx, name, name_len,
1765			       location.objectid, d_type);
1766
1767		if (refcount_dec_and_test(&curr->refs))
1768			kfree(curr);
1769
1770		if (over)
1771			return 1;
1772		ctx->pos++;
1773	}
1774	return 0;
1775}
1776
1777static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
1778				  struct btrfs_inode_item *inode_item,
1779				  struct inode *inode)
1780{
1781	u64 flags;
1782
1783	btrfs_set_stack_inode_uid(inode_item, i_uid_read(inode));
1784	btrfs_set_stack_inode_gid(inode_item, i_gid_read(inode));
1785	btrfs_set_stack_inode_size(inode_item, BTRFS_I(inode)->disk_i_size);
1786	btrfs_set_stack_inode_mode(inode_item, inode->i_mode);
1787	btrfs_set_stack_inode_nlink(inode_item, inode->i_nlink);
1788	btrfs_set_stack_inode_nbytes(inode_item, inode_get_bytes(inode));
1789	btrfs_set_stack_inode_generation(inode_item,
1790					 BTRFS_I(inode)->generation);
1791	btrfs_set_stack_inode_sequence(inode_item,
1792				       inode_peek_iversion(inode));
1793	btrfs_set_stack_inode_transid(inode_item, trans->transid);
1794	btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
1795	flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
1796					  BTRFS_I(inode)->ro_flags);
1797	btrfs_set_stack_inode_flags(inode_item, flags);
1798	btrfs_set_stack_inode_block_group(inode_item, 0);
1799
1800	btrfs_set_stack_timespec_sec(&inode_item->atime,
1801				     inode->i_atime.tv_sec);
1802	btrfs_set_stack_timespec_nsec(&inode_item->atime,
1803				      inode->i_atime.tv_nsec);
1804
1805	btrfs_set_stack_timespec_sec(&inode_item->mtime,
1806				     inode->i_mtime.tv_sec);
1807	btrfs_set_stack_timespec_nsec(&inode_item->mtime,
1808				      inode->i_mtime.tv_nsec);
1809
1810	btrfs_set_stack_timespec_sec(&inode_item->ctime,
1811				     inode->i_ctime.tv_sec);
1812	btrfs_set_stack_timespec_nsec(&inode_item->ctime,
1813				      inode->i_ctime.tv_nsec);
1814
1815	btrfs_set_stack_timespec_sec(&inode_item->otime,
1816				     BTRFS_I(inode)->i_otime.tv_sec);
1817	btrfs_set_stack_timespec_nsec(&inode_item->otime,
1818				     BTRFS_I(inode)->i_otime.tv_nsec);
1819}
1820
1821int btrfs_fill_inode(struct inode *inode, u32 *rdev)
1822{
1823	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1824	struct btrfs_delayed_node *delayed_node;
1825	struct btrfs_inode_item *inode_item;
1826
1827	delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
1828	if (!delayed_node)
1829		return -ENOENT;
1830
1831	mutex_lock(&delayed_node->mutex);
1832	if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1833		mutex_unlock(&delayed_node->mutex);
1834		btrfs_release_delayed_node(delayed_node);
1835		return -ENOENT;
1836	}
1837
1838	inode_item = &delayed_node->inode_item;
1839
1840	i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
1841	i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
1842	btrfs_i_size_write(BTRFS_I(inode), btrfs_stack_inode_size(inode_item));
1843	btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
1844			round_up(i_size_read(inode), fs_info->sectorsize));
1845	inode->i_mode = btrfs_stack_inode_mode(inode_item);
1846	set_nlink(inode, btrfs_stack_inode_nlink(inode_item));
1847	inode_set_bytes(inode, btrfs_stack_inode_nbytes(inode_item));
1848	BTRFS_I(inode)->generation = btrfs_stack_inode_generation(inode_item);
1849        BTRFS_I(inode)->last_trans = btrfs_stack_inode_transid(inode_item);
1850
1851	inode_set_iversion_queried(inode,
1852				   btrfs_stack_inode_sequence(inode_item));
1853	inode->i_rdev = 0;
1854	*rdev = btrfs_stack_inode_rdev(inode_item);
1855	btrfs_inode_split_flags(btrfs_stack_inode_flags(inode_item),
1856				&BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags);
1857
1858	inode->i_atime.tv_sec = btrfs_stack_timespec_sec(&inode_item->atime);
1859	inode->i_atime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->atime);
1860
1861	inode->i_mtime.tv_sec = btrfs_stack_timespec_sec(&inode_item->mtime);
1862	inode->i_mtime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->mtime);
1863
1864	inode->i_ctime.tv_sec = btrfs_stack_timespec_sec(&inode_item->ctime);
1865	inode->i_ctime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->ctime);
1866
1867	BTRFS_I(inode)->i_otime.tv_sec =
1868		btrfs_stack_timespec_sec(&inode_item->otime);
1869	BTRFS_I(inode)->i_otime.tv_nsec =
1870		btrfs_stack_timespec_nsec(&inode_item->otime);
1871
1872	inode->i_generation = BTRFS_I(inode)->generation;
1873	BTRFS_I(inode)->index_cnt = (u64)-1;
1874
1875	mutex_unlock(&delayed_node->mutex);
1876	btrfs_release_delayed_node(delayed_node);
1877	return 0;
1878}
1879
1880int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
1881			       struct btrfs_root *root,
1882			       struct btrfs_inode *inode)
1883{
1884	struct btrfs_delayed_node *delayed_node;
1885	int ret = 0;
1886
1887	delayed_node = btrfs_get_or_create_delayed_node(inode);
1888	if (IS_ERR(delayed_node))
1889		return PTR_ERR(delayed_node);
1890
1891	mutex_lock(&delayed_node->mutex);
1892	if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1893		fill_stack_inode_item(trans, &delayed_node->inode_item,
1894				      &inode->vfs_inode);
1895		goto release_node;
1896	}
1897
1898	ret = btrfs_delayed_inode_reserve_metadata(trans, root, delayed_node);
 
1899	if (ret)
1900		goto release_node;
1901
1902	fill_stack_inode_item(trans, &delayed_node->inode_item, &inode->vfs_inode);
1903	set_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
1904	delayed_node->count++;
1905	atomic_inc(&root->fs_info->delayed_root->items);
1906release_node:
1907	mutex_unlock(&delayed_node->mutex);
1908	btrfs_release_delayed_node(delayed_node);
1909	return ret;
1910}
1911
1912int btrfs_delayed_delete_inode_ref(struct btrfs_inode *inode)
1913{
1914	struct btrfs_fs_info *fs_info = inode->root->fs_info;
1915	struct btrfs_delayed_node *delayed_node;
1916
1917	/*
1918	 * we don't do delayed inode updates during log recovery because it
1919	 * leads to enospc problems.  This means we also can't do
1920	 * delayed inode refs
1921	 */
1922	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
1923		return -EAGAIN;
1924
1925	delayed_node = btrfs_get_or_create_delayed_node(inode);
1926	if (IS_ERR(delayed_node))
1927		return PTR_ERR(delayed_node);
1928
1929	/*
1930	 * We don't reserve space for inode ref deletion is because:
1931	 * - We ONLY do async inode ref deletion for the inode who has only
1932	 *   one link(i_nlink == 1), it means there is only one inode ref.
1933	 *   And in most case, the inode ref and the inode item are in the
1934	 *   same leaf, and we will deal with them at the same time.
1935	 *   Since we are sure we will reserve the space for the inode item,
1936	 *   it is unnecessary to reserve space for inode ref deletion.
1937	 * - If the inode ref and the inode item are not in the same leaf,
1938	 *   We also needn't worry about enospc problem, because we reserve
1939	 *   much more space for the inode update than it needs.
1940	 * - At the worst, we can steal some space from the global reservation.
1941	 *   It is very rare.
1942	 */
1943	mutex_lock(&delayed_node->mutex);
1944	if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags))
1945		goto release_node;
1946
1947	set_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags);
1948	delayed_node->count++;
1949	atomic_inc(&fs_info->delayed_root->items);
1950release_node:
1951	mutex_unlock(&delayed_node->mutex);
1952	btrfs_release_delayed_node(delayed_node);
1953	return 0;
1954}
1955
1956static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
1957{
1958	struct btrfs_root *root = delayed_node->root;
1959	struct btrfs_fs_info *fs_info = root->fs_info;
1960	struct btrfs_delayed_item *curr_item, *prev_item;
1961
1962	mutex_lock(&delayed_node->mutex);
1963	curr_item = __btrfs_first_delayed_insertion_item(delayed_node);
1964	while (curr_item) {
 
1965		prev_item = curr_item;
1966		curr_item = __btrfs_next_delayed_item(prev_item);
1967		btrfs_release_delayed_item(prev_item);
1968	}
1969
1970	if (delayed_node->index_item_leaves > 0) {
1971		btrfs_delayed_item_release_leaves(delayed_node,
1972					  delayed_node->index_item_leaves);
1973		delayed_node->index_item_leaves = 0;
1974	}
1975
1976	curr_item = __btrfs_first_delayed_deletion_item(delayed_node);
1977	while (curr_item) {
1978		btrfs_delayed_item_release_metadata(root, curr_item);
1979		prev_item = curr_item;
1980		curr_item = __btrfs_next_delayed_item(prev_item);
1981		btrfs_release_delayed_item(prev_item);
1982	}
1983
1984	btrfs_release_delayed_iref(delayed_node);
 
1985
1986	if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
1987		btrfs_delayed_inode_release_metadata(fs_info, delayed_node, false);
1988		btrfs_release_delayed_inode(delayed_node);
1989	}
1990	mutex_unlock(&delayed_node->mutex);
1991}
1992
1993void btrfs_kill_delayed_inode_items(struct btrfs_inode *inode)
1994{
1995	struct btrfs_delayed_node *delayed_node;
1996
1997	delayed_node = btrfs_get_delayed_node(inode);
1998	if (!delayed_node)
1999		return;
2000
2001	__btrfs_kill_delayed_node(delayed_node);
2002	btrfs_release_delayed_node(delayed_node);
2003}
2004
2005void btrfs_kill_all_delayed_nodes(struct btrfs_root *root)
2006{
2007	u64 inode_id = 0;
2008	struct btrfs_delayed_node *delayed_nodes[8];
2009	int i, n;
2010
2011	while (1) {
2012		spin_lock(&root->inode_lock);
2013		n = radix_tree_gang_lookup(&root->delayed_nodes_tree,
2014					   (void **)delayed_nodes, inode_id,
2015					   ARRAY_SIZE(delayed_nodes));
2016		if (!n) {
2017			spin_unlock(&root->inode_lock);
2018			break;
2019		}
2020
2021		inode_id = delayed_nodes[n - 1]->inode_id + 1;
2022		for (i = 0; i < n; i++) {
2023			/*
2024			 * Don't increase refs in case the node is dead and
2025			 * about to be removed from the tree in the loop below
2026			 */
2027			if (!refcount_inc_not_zero(&delayed_nodes[i]->refs))
2028				delayed_nodes[i] = NULL;
2029		}
2030		spin_unlock(&root->inode_lock);
2031
2032		for (i = 0; i < n; i++) {
2033			if (!delayed_nodes[i])
2034				continue;
2035			__btrfs_kill_delayed_node(delayed_nodes[i]);
2036			btrfs_release_delayed_node(delayed_nodes[i]);
2037		}
2038	}
2039}
2040
2041void btrfs_destroy_delayed_inodes(struct btrfs_fs_info *fs_info)
2042{
2043	struct btrfs_delayed_node *curr_node, *prev_node;
2044
2045	curr_node = btrfs_first_delayed_node(fs_info->delayed_root);
2046	while (curr_node) {
2047		__btrfs_kill_delayed_node(curr_node);
2048
2049		prev_node = curr_node;
2050		curr_node = btrfs_next_delayed_node(curr_node);
2051		btrfs_release_delayed_node(prev_node);
2052	}
2053}
2054
2055void btrfs_log_get_delayed_items(struct btrfs_inode *inode,
2056				 struct list_head *ins_list,
2057				 struct list_head *del_list)
2058{
2059	struct btrfs_delayed_node *node;
2060	struct btrfs_delayed_item *item;
2061
2062	node = btrfs_get_delayed_node(inode);
2063	if (!node)
2064		return;
2065
2066	mutex_lock(&node->mutex);
2067	item = __btrfs_first_delayed_insertion_item(node);
2068	while (item) {
2069		/*
2070		 * It's possible that the item is already in a log list. This
2071		 * can happen in case two tasks are trying to log the same
2072		 * directory. For example if we have tasks A and task B:
2073		 *
2074		 * Task A collected the delayed items into a log list while
2075		 * under the inode's log_mutex (at btrfs_log_inode()), but it
2076		 * only releases the items after logging the inodes they point
2077		 * to (if they are new inodes), which happens after unlocking
2078		 * the log mutex;
2079		 *
2080		 * Task B enters btrfs_log_inode() and acquires the log_mutex
2081		 * of the same directory inode, before task B releases the
2082		 * delayed items. This can happen for example when logging some
2083		 * inode we need to trigger logging of its parent directory, so
2084		 * logging two files that have the same parent directory can
2085		 * lead to this.
2086		 *
2087		 * If this happens, just ignore delayed items already in a log
2088		 * list. All the tasks logging the directory are under a log
2089		 * transaction and whichever finishes first can not sync the log
2090		 * before the other completes and leaves the log transaction.
2091		 */
2092		if (!item->logged && list_empty(&item->log_list)) {
2093			refcount_inc(&item->refs);
2094			list_add_tail(&item->log_list, ins_list);
2095		}
2096		item = __btrfs_next_delayed_item(item);
2097	}
2098
2099	item = __btrfs_first_delayed_deletion_item(node);
2100	while (item) {
2101		/* It may be non-empty, for the same reason mentioned above. */
2102		if (!item->logged && list_empty(&item->log_list)) {
2103			refcount_inc(&item->refs);
2104			list_add_tail(&item->log_list, del_list);
2105		}
2106		item = __btrfs_next_delayed_item(item);
2107	}
2108	mutex_unlock(&node->mutex);
2109
2110	/*
2111	 * We are called during inode logging, which means the inode is in use
2112	 * and can not be evicted before we finish logging the inode. So we never
2113	 * have the last reference on the delayed inode.
2114	 * Also, we don't use btrfs_release_delayed_node() because that would
2115	 * requeue the delayed inode (change its order in the list of prepared
2116	 * nodes) and we don't want to do such change because we don't create or
2117	 * delete delayed items.
2118	 */
2119	ASSERT(refcount_read(&node->refs) > 1);
2120	refcount_dec(&node->refs);
2121}
2122
2123void btrfs_log_put_delayed_items(struct btrfs_inode *inode,
2124				 struct list_head *ins_list,
2125				 struct list_head *del_list)
2126{
2127	struct btrfs_delayed_node *node;
2128	struct btrfs_delayed_item *item;
2129	struct btrfs_delayed_item *next;
2130
2131	node = btrfs_get_delayed_node(inode);
2132	if (!node)
2133		return;
2134
2135	mutex_lock(&node->mutex);
2136
2137	list_for_each_entry_safe(item, next, ins_list, log_list) {
2138		item->logged = true;
2139		list_del_init(&item->log_list);
2140		if (refcount_dec_and_test(&item->refs))
2141			kfree(item);
2142	}
2143
2144	list_for_each_entry_safe(item, next, del_list, log_list) {
2145		item->logged = true;
2146		list_del_init(&item->log_list);
2147		if (refcount_dec_and_test(&item->refs))
2148			kfree(item);
2149	}
2150
2151	mutex_unlock(&node->mutex);
2152
2153	/*
2154	 * We are called during inode logging, which means the inode is in use
2155	 * and can not be evicted before we finish logging the inode. So we never
2156	 * have the last reference on the delayed inode.
2157	 * Also, we don't use btrfs_release_delayed_node() because that would
2158	 * requeue the delayed inode (change its order in the list of prepared
2159	 * nodes) and we don't want to do such change because we don't create or
2160	 * delete delayed items.
2161	 */
2162	ASSERT(refcount_read(&node->refs) > 1);
2163	refcount_dec(&node->refs);
2164}