Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2200 insertions, 0 deletions

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
new file mode 100644
index 0000000000..16f9e5f474
--- /dev/null
+++ b/fs/btrfs/delayed-inode.c
@@ -0,0 +1,2200 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2011 Fujitsu.  All rights reserved.
+ * Written by Miao Xie <miaox@cn.fujitsu.com>
+ */
+
+#include <linux/slab.h>
+#include <linux/iversion.h>
+#include "ctree.h"
+#include "fs.h"
+#include "messages.h"
+#include "misc.h"
+#include "delayed-inode.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "qgroup.h"
+#include "locking.h"
+#include "inode-item.h"
+#include "space-info.h"
+#include "accessors.h"
+#include "file-item.h"
+
+#define BTRFS_DELAYED_WRITEBACK		512
+#define BTRFS_DELAYED_BACKGROUND	128
+#define BTRFS_DELAYED_BATCH		16
+
+static struct kmem_cache *delayed_node_cache;
+
+int __init btrfs_delayed_inode_init(void)
+{
+	delayed_node_cache = kmem_cache_create("btrfs_delayed_node",
+					sizeof(struct btrfs_delayed_node),
+					0,
+					SLAB_MEM_SPREAD,
+					NULL);
+	if (!delayed_node_cache)
+		return -ENOMEM;
+	return 0;
+}
+
+void __cold btrfs_delayed_inode_exit(void)
+{
+	kmem_cache_destroy(delayed_node_cache);
+}
+
+static inline void btrfs_init_delayed_node(
+				struct btrfs_delayed_node *delayed_node,
+				struct btrfs_root *root, u64 inode_id)
+{
+	delayed_node->root = root;
+	delayed_node->inode_id = inode_id;
+	refcount_set(&delayed_node->refs, 0);
+	delayed_node->ins_root = RB_ROOT_CACHED;
+	delayed_node->del_root = RB_ROOT_CACHED;
+	mutex_init(&delayed_node->mutex);
+	INIT_LIST_HEAD(&delayed_node->n_list);
+	INIT_LIST_HEAD(&delayed_node->p_list);
+}
+
+static struct btrfs_delayed_node *btrfs_get_delayed_node(
+		struct btrfs_inode *btrfs_inode)
+{
+	struct btrfs_root *root = btrfs_inode->root;
+	u64 ino = btrfs_ino(btrfs_inode);
+	struct btrfs_delayed_node *node;
+
+	node = READ_ONCE(btrfs_inode->delayed_node);
+	if (node) {
+		refcount_inc(&node->refs);
+		return node;
+	}
+
+	spin_lock(&root->inode_lock);
+	node = radix_tree_lookup(&root->delayed_nodes_tree, ino);
+
+	if (node) {
+		if (btrfs_inode->delayed_node) {
+			refcount_inc(&node->refs);	/* can be accessed */
+			BUG_ON(btrfs_inode->delayed_node != node);
+			spin_unlock(&root->inode_lock);
+			return node;
+		}
+
+		/*
+		 * It's possible that we're racing into the middle of removing
+		 * this node from the radix tree.  In this case, the refcount
+		 * was zero and it should never go back to one.  Just return
+		 * NULL like it was never in the radix at all; our release
+		 * function is in the process of removing it.
+		 *
+		 * Some implementations of refcount_inc refuse to bump the
+		 * refcount once it has hit zero.  If we don't do this dance
+		 * here, refcount_inc() may decide to just WARN_ONCE() instead
+		 * of actually bumping the refcount.
+		 *
+		 * If this node is properly in the radix, we want to bump the
+		 * refcount twice, once for the inode and once for this get
+		 * operation.
+		 */
+		if (refcount_inc_not_zero(&node->refs)) {
+			refcount_inc(&node->refs);
+			btrfs_inode->delayed_node = node;
+		} else {
+			node = NULL;
+		}
+
+		spin_unlock(&root->inode_lock);
+		return node;
+	}
+	spin_unlock(&root->inode_lock);
+
+	return NULL;
+}
+
+/* Will return either the node or PTR_ERR(-ENOMEM) */
+static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
+		struct btrfs_inode *btrfs_inode)
+{
+	struct btrfs_delayed_node *node;
+	struct btrfs_root *root = btrfs_inode->root;
+	u64 ino = btrfs_ino(btrfs_inode);
+	int ret;
+
+again:
+	node = btrfs_get_delayed_node(btrfs_inode);
+	if (node)
+		return node;
+
+	node = kmem_cache_zalloc(delayed_node_cache, GFP_NOFS);
+	if (!node)
+		return ERR_PTR(-ENOMEM);
+	btrfs_init_delayed_node(node, root, ino);
+
+	/* cached in the btrfs inode and can be accessed */
+	refcount_set(&node->refs, 2);
+
+	ret = radix_tree_preload(GFP_NOFS);
+	if (ret) {
+		kmem_cache_free(delayed_node_cache, node);
+		return ERR_PTR(ret);
+	}
+
+	spin_lock(&root->inode_lock);
+	ret = radix_tree_insert(&root->delayed_nodes_tree, ino, node);
+	if (ret == -EEXIST) {
+		spin_unlock(&root->inode_lock);
+		kmem_cache_free(delayed_node_cache, node);
+		radix_tree_preload_end();
+		goto again;
+	}
+	btrfs_inode->delayed_node = node;
+	spin_unlock(&root->inode_lock);
+	radix_tree_preload_end();
+
+	return node;
+}
+
+/*
+ * Call it when holding delayed_node->mutex
+ *
+ * If mod = 1, add this node into the prepared list.
+ */
+static void btrfs_queue_delayed_node(struct btrfs_delayed_root *root,
+				     struct btrfs_delayed_node *node,
+				     int mod)
+{
+	spin_lock(&root->lock);
+	if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
+		if (!list_empty(&node->p_list))
+			list_move_tail(&node->p_list, &root->prepare_list);
+		else if (mod)
+			list_add_tail(&node->p_list, &root->prepare_list);
+	} else {
+		list_add_tail(&node->n_list, &root->node_list);
+		list_add_tail(&node->p_list, &root->prepare_list);
+		refcount_inc(&node->refs);	/* inserted into list */
+		root->nodes++;
+		set_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
+	}
+	spin_unlock(&root->lock);
+}
+
+/* Call it when holding delayed_node->mutex */
+static void btrfs_dequeue_delayed_node(struct btrfs_delayed_root *root,
+				       struct btrfs_delayed_node *node)
+{
+	spin_lock(&root->lock);
+	if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
+		root->nodes--;
+		refcount_dec(&node->refs);	/* not in the list */
+		list_del_init(&node->n_list);
+		if (!list_empty(&node->p_list))
+			list_del_init(&node->p_list);
+		clear_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
+	}
+	spin_unlock(&root->lock);
+}
+
+static struct btrfs_delayed_node *btrfs_first_delayed_node(
+			struct btrfs_delayed_root *delayed_root)
+{
+	struct list_head *p;
+	struct btrfs_delayed_node *node = NULL;
+
+	spin_lock(&delayed_root->lock);
+	if (list_empty(&delayed_root->node_list))
+		goto out;
+
+	p = delayed_root->node_list.next;
+	node = list_entry(p, struct btrfs_delayed_node, n_list);
+	refcount_inc(&node->refs);
+out:
+	spin_unlock(&delayed_root->lock);
+
+	return node;
+}
+
+static struct btrfs_delayed_node *btrfs_next_delayed_node(
+						struct btrfs_delayed_node *node)
+{
+	struct btrfs_delayed_root *delayed_root;
+	struct list_head *p;
+	struct btrfs_delayed_node *next = NULL;
+
+	delayed_root = node->root->fs_info->delayed_root;
+	spin_lock(&delayed_root->lock);
+	if (!test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
+		/* not in the list */
+		if (list_empty(&delayed_root->node_list))
+			goto out;
+		p = delayed_root->node_list.next;
+	} else if (list_is_last(&node->n_list, &delayed_root->node_list))
+		goto out;
+	else
+		p = node->n_list.next;
+
+	next = list_entry(p, struct btrfs_delayed_node, n_list);
+	refcount_inc(&next->refs);
+out:
+	spin_unlock(&delayed_root->lock);
+
+	return next;
+}
+
+static void __btrfs_release_delayed_node(
+				struct btrfs_delayed_node *delayed_node,
+				int mod)
+{
+	struct btrfs_delayed_root *delayed_root;
+
+	if (!delayed_node)
+		return;
+
+	delayed_root = delayed_node->root->fs_info->delayed_root;
+
+	mutex_lock(&delayed_node->mutex);
+	if (delayed_node->count)
+		btrfs_queue_delayed_node(delayed_root, delayed_node, mod);
+	else
+		btrfs_dequeue_delayed_node(delayed_root, delayed_node);
+	mutex_unlock(&delayed_node->mutex);
+
+	if (refcount_dec_and_test(&delayed_node->refs)) {
+		struct btrfs_root *root = delayed_node->root;
+
+		spin_lock(&root->inode_lock);
+		/*
+		 * Once our refcount goes to zero, nobody is allowed to bump it
+		 * back up.  We can delete it now.
+		 */
+		ASSERT(refcount_read(&delayed_node->refs) == 0);
+		radix_tree_delete(&root->delayed_nodes_tree,
+				  delayed_node->inode_id);
+		spin_unlock(&root->inode_lock);
+		kmem_cache_free(delayed_node_cache, delayed_node);
+	}
+}
+
+static inline void btrfs_release_delayed_node(struct btrfs_delayed_node *node)
+{
+	__btrfs_release_delayed_node(node, 0);
+}
+
+static struct btrfs_delayed_node *btrfs_first_prepared_delayed_node(
+					struct btrfs_delayed_root *delayed_root)
+{
+	struct list_head *p;
+	struct btrfs_delayed_node *node = NULL;
+
+	spin_lock(&delayed_root->lock);
+	if (list_empty(&delayed_root->prepare_list))
+		goto out;
+
+	p = delayed_root->prepare_list.next;
+	list_del_init(p);
+	node = list_entry(p, struct btrfs_delayed_node, p_list);
+	refcount_inc(&node->refs);
+out:
+	spin_unlock(&delayed_root->lock);
+
+	return node;
+}
+
+static inline void btrfs_release_prepared_delayed_node(
+					struct btrfs_delayed_node *node)
+{
+	__btrfs_release_delayed_node(node, 1);
+}
+
+static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u16 data_len,
+					   struct btrfs_delayed_node *node,
+					   enum btrfs_delayed_item_type type)
+{
+	struct btrfs_delayed_item *item;
+
+	item = kmalloc(struct_size(item, data, data_len), GFP_NOFS);
+	if (item) {
+		item->data_len = data_len;
+		item->type = type;
+		item->bytes_reserved = 0;
+		item->delayed_node = node;
+		RB_CLEAR_NODE(&item->rb_node);
+		INIT_LIST_HEAD(&item->log_list);
+		item->logged = false;
+		refcount_set(&item->refs, 1);
+	}
+	return item;
+}
+
+/*
+ * __btrfs_lookup_delayed_item - look up the delayed item by key
+ * @delayed_node: pointer to the delayed node
+ * @index:	  the dir index value to lookup (offset of a dir index key)
+ *
+ * Note: if we don't find the right item, we will return the prev item and
+ * the next item.
+ */
+static struct btrfs_delayed_item *__btrfs_lookup_delayed_item(
+				struct rb_root *root,
+				u64 index)
+{
+	struct rb_node *node = root->rb_node;
+	struct btrfs_delayed_item *delayed_item = NULL;
+
+	while (node) {
+		delayed_item = rb_entry(node, struct btrfs_delayed_item,
+					rb_node);
+		if (delayed_item->index < index)
+			node = node->rb_right;
+		else if (delayed_item->index > index)
+			node = node->rb_left;
+		else
+			return delayed_item;
+	}
+
+	return NULL;
+}
+
+static int __btrfs_add_delayed_item(struct btrfs_delayed_node *delayed_node,
+				    struct btrfs_delayed_item *ins)
+{
+	struct rb_node **p, *node;
+	struct rb_node *parent_node = NULL;
+	struct rb_root_cached *root;
+	struct btrfs_delayed_item *item;
+	bool leftmost = true;
+
+	if (ins->type == BTRFS_DELAYED_INSERTION_ITEM)
+		root = &delayed_node->ins_root;
+	else
+		root = &delayed_node->del_root;
+
+	p = &root->rb_root.rb_node;
+	node = &ins->rb_node;
+
+	while (*p) {
+		parent_node = *p;
+		item = rb_entry(parent_node, struct btrfs_delayed_item,
+				 rb_node);
+
+		if (item->index < ins->index) {
+			p = &(*p)->rb_right;
+			leftmost = false;
+		} else if (item->index > ins->index) {
+			p = &(*p)->rb_left;
+		} else {
+			return -EEXIST;
+		}
+	}
+
+	rb_link_node(node, parent_node, p);
+	rb_insert_color_cached(node, root, leftmost);
+
+	if (ins->type == BTRFS_DELAYED_INSERTION_ITEM &&
+	    ins->index >= delayed_node->index_cnt)
+		delayed_node->index_cnt = ins->index + 1;
+
+	delayed_node->count++;
+	atomic_inc(&delayed_node->root->fs_info->delayed_root->items);
+	return 0;
+}
+
+static void finish_one_item(struct btrfs_delayed_root *delayed_root)
+{
+	int seq = atomic_inc_return(&delayed_root->items_seq);
+
+	/* atomic_dec_return implies a barrier */
+	if ((atomic_dec_return(&delayed_root->items) <
+	    BTRFS_DELAYED_BACKGROUND || seq % BTRFS_DELAYED_BATCH == 0))
+		cond_wake_up_nomb(&delayed_root->wait);
+}
+
+static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item)
+{
+	struct btrfs_delayed_node *delayed_node = delayed_item->delayed_node;
+	struct rb_root_cached *root;
+	struct btrfs_delayed_root *delayed_root;
+
+	/* Not inserted, ignore it. */
+	if (RB_EMPTY_NODE(&delayed_item->rb_node))
+		return;
+
+	/* If it's in a rbtree, then we need to have delayed node locked. */
+	lockdep_assert_held(&delayed_node->mutex);
+
+	delayed_root = delayed_node->root->fs_info->delayed_root;
+
+	BUG_ON(!delayed_root);
+
+	if (delayed_item->type == BTRFS_DELAYED_INSERTION_ITEM)
+		root = &delayed_node->ins_root;
+	else
+		root = &delayed_node->del_root;
+
+	rb_erase_cached(&delayed_item->rb_node, root);
+	RB_CLEAR_NODE(&delayed_item->rb_node);
+	delayed_node->count--;
+
+	finish_one_item(delayed_root);
+}
+
+static void btrfs_release_delayed_item(struct btrfs_delayed_item *item)
+{
+	if (item) {
+		__btrfs_remove_delayed_item(item);
+		if (refcount_dec_and_test(&item->refs))
+			kfree(item);
+	}
+}
+
+static struct btrfs_delayed_item *__btrfs_first_delayed_insertion_item(
+					struct btrfs_delayed_node *delayed_node)
+{
+	struct rb_node *p;
+	struct btrfs_delayed_item *item = NULL;
+
+	p = rb_first_cached(&delayed_node->ins_root);
+	if (p)
+		item = rb_entry(p, struct btrfs_delayed_item, rb_node);
+
+	return item;
+}
+
+static struct btrfs_delayed_item *__btrfs_first_delayed_deletion_item(
+					struct btrfs_delayed_node *delayed_node)
+{
+	struct rb_node *p;
+	struct btrfs_delayed_item *item = NULL;
+
+	p = rb_first_cached(&delayed_node->del_root);
+	if (p)
+		item = rb_entry(p, struct btrfs_delayed_item, rb_node);
+
+	return item;
+}
+
+static struct btrfs_delayed_item *__btrfs_next_delayed_item(
+						struct btrfs_delayed_item *item)
+{
+	struct rb_node *p;
+	struct btrfs_delayed_item *next = NULL;
+
+	p = rb_next(&item->rb_node);
+	if (p)
+		next = rb_entry(p, struct btrfs_delayed_item, rb_node);
+
+	return next;
+}
+
+static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
+					       struct btrfs_delayed_item *item)
+{
+	struct btrfs_block_rsv *src_rsv;
+	struct btrfs_block_rsv *dst_rsv;
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	u64 num_bytes;
+	int ret;
+
+	if (!trans->bytes_reserved)
+		return 0;
+
+	src_rsv = trans->block_rsv;
+	dst_rsv = &fs_info->delayed_block_rsv;
+
+	num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
+
+	/*
+	 * Here we migrate space rsv from transaction rsv, since have already
+	 * reserved space when starting a transaction.  So no need to reserve
+	 * qgroup space here.
+	 */
+	ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
+	if (!ret) {
+		trace_btrfs_space_reservation(fs_info, "delayed_item",
+					      item->delayed_node->inode_id,
+					      num_bytes, 1);
+		/*
+		 * For insertions we track reserved metadata space by accounting
+		 * for the number of leaves that will be used, based on the delayed
+		 * node's index_items_size field.
+		 */
+		if (item->type == BTRFS_DELAYED_DELETION_ITEM)
+			item->bytes_reserved = num_bytes;
+	}
+
+	return ret;
+}
+
+static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
+						struct btrfs_delayed_item *item)
+{
+	struct btrfs_block_rsv *rsv;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+
+	if (!item->bytes_reserved)
+		return;
+
+	rsv = &fs_info->delayed_block_rsv;
+	/*
+	 * Check btrfs_delayed_item_reserve_metadata() to see why we don't need
+	 * to release/reserve qgroup space.
+	 */
+	trace_btrfs_space_reservation(fs_info, "delayed_item",
+				      item->delayed_node->inode_id,
+				      item->bytes_reserved, 0);
+	btrfs_block_rsv_release(fs_info, rsv, item->bytes_reserved, NULL);
+}
+
+static void btrfs_delayed_item_release_leaves(struct btrfs_delayed_node *node,
+					      unsigned int num_leaves)
+{
+	struct btrfs_fs_info *fs_info = node->root->fs_info;
+	const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, num_leaves);
+
+	/* There are no space reservations during log replay, bail out. */
+	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
+		return;
+
+	trace_btrfs_space_reservation(fs_info, "delayed_item", node->inode_id,
+				      bytes, 0);
+	btrfs_block_rsv_release(fs_info, &fs_info->delayed_block_rsv, bytes, NULL);
+}
+
+static int btrfs_delayed_inode_reserve_metadata(
+					struct btrfs_trans_handle *trans,
+					struct btrfs_root *root,
+					struct btrfs_delayed_node *node)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_block_rsv *src_rsv;
+	struct btrfs_block_rsv *dst_rsv;
+	u64 num_bytes;
+	int ret;
+
+	src_rsv = trans->block_rsv;
+	dst_rsv = &fs_info->delayed_block_rsv;
+
+	num_bytes = btrfs_calc_metadata_size(fs_info, 1);
+
+	/*
+	 * btrfs_dirty_inode will update the inode under btrfs_join_transaction
+	 * which doesn't reserve space for speed.  This is a problem since we
+	 * still need to reserve space for this update, so try to reserve the
+	 * space.
+	 *
+	 * Now if src_rsv == delalloc_block_rsv we'll let it just steal since
+	 * we always reserve enough to update the inode item.
+	 */
+	if (!src_rsv || (!trans->bytes_reserved &&
+			 src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) {
+		ret = btrfs_qgroup_reserve_meta(root, num_bytes,
+					  BTRFS_QGROUP_RSV_META_PREALLOC, true);
+		if (ret < 0)
+			return ret;
+		ret = btrfs_block_rsv_add(fs_info, dst_rsv, num_bytes,
+					  BTRFS_RESERVE_NO_FLUSH);
+		/* NO_FLUSH could only fail with -ENOSPC */
+		ASSERT(ret == 0 || ret == -ENOSPC);
+		if (ret)
+			btrfs_qgroup_free_meta_prealloc(root, num_bytes);
+	} else {
+		ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, true);
+	}
+
+	if (!ret) {
+		trace_btrfs_space_reservation(fs_info, "delayed_inode",
+					      node->inode_id, num_bytes, 1);
+		node->bytes_reserved = num_bytes;
+	}
+
+	return ret;
+}
+
+static void btrfs_delayed_inode_release_metadata(struct btrfs_fs_info *fs_info,
+						struct btrfs_delayed_node *node,
+						bool qgroup_free)
+{
+	struct btrfs_block_rsv *rsv;
+
+	if (!node->bytes_reserved)
+		return;
+
+	rsv = &fs_info->delayed_block_rsv;
+	trace_btrfs_space_reservation(fs_info, "delayed_inode",
+				      node->inode_id, node->bytes_reserved, 0);
+	btrfs_block_rsv_release(fs_info, rsv, node->bytes_reserved, NULL);
+	if (qgroup_free)
+		btrfs_qgroup_free_meta_prealloc(node->root,
+				node->bytes_reserved);
+	else
+		btrfs_qgroup_convert_reserved_meta(node->root,
+				node->bytes_reserved);
+	node->bytes_reserved = 0;
+}
+
+/*
+ * Insert a single delayed item or a batch of delayed items, as many as possible
+ * that fit in a leaf. The delayed items (dir index keys) are sorted by their key
+ * in the rbtree, and if there's a gap between two consecutive dir index items,
+ * then it means at some point we had delayed dir indexes to add but they got
+ * removed (by btrfs_delete_delayed_dir_index()) before we attempted to flush them
+ * into the subvolume tree. Dir index keys also have their offsets coming from a
+ * monotonically increasing counter, so we can't get new keys with an offset that
+ * fits within a gap between delayed dir index items.
+ */
+static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
+				     struct btrfs_root *root,
+				     struct btrfs_path *path,
+				     struct btrfs_delayed_item *first_item)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_delayed_node *node = first_item->delayed_node;
+	LIST_HEAD(item_list);
+	struct btrfs_delayed_item *curr;
+	struct btrfs_delayed_item *next;
+	const int max_size = BTRFS_LEAF_DATA_SIZE(fs_info);
+	struct btrfs_item_batch batch;
+	struct btrfs_key first_key;
+	const u32 first_data_size = first_item->data_len;
+	int total_size;
+	char *ins_data = NULL;
+	int ret;
+	bool continuous_keys_only = false;
+
+	lockdep_assert_held(&node->mutex);
+
+	/*
+	 * During normal operation the delayed index offset is continuously
+	 * increasing, so we can batch insert all items as there will not be any
+	 * overlapping keys in the tree.
+	 *
+	 * The exception to this is log replay, where we may have interleaved
+	 * offsets in the tree, so our batch needs to be continuous keys only in
+	 * order to ensure we do not end up with out of order items in our leaf.
+	 */
+	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
+		continuous_keys_only = true;
+
+	/*
+	 * For delayed items to insert, we track reserved metadata bytes based
+	 * on the number of leaves that we will use.
+	 * See btrfs_insert_delayed_dir_index() and
+	 * btrfs_delayed_item_reserve_metadata()).
+	 */
+	ASSERT(first_item->bytes_reserved == 0);
+
+	list_add_tail(&first_item->tree_list, &item_list);
+	batch.total_data_size = first_data_size;
+	batch.nr = 1;
+	total_size = first_data_size + sizeof(struct btrfs_item);
+	curr = first_item;
+
+	while (true) {
+		int next_size;
+
+		next = __btrfs_next_delayed_item(curr);
+		if (!next)
+			break;
+
+		/*
+		 * We cannot allow gaps in the key space if we're doing log
+		 * replay.
+		 */
+		if (continuous_keys_only && (next->index != curr->index + 1))
+			break;
+
+		ASSERT(next->bytes_reserved == 0);
+
+		next_size = next->data_len + sizeof(struct btrfs_item);
+		if (total_size + next_size > max_size)
+			break;
+
+		list_add_tail(&next->tree_list, &item_list);
+		batch.nr++;
+		total_size += next_size;
+		batch.total_data_size += next->data_len;
+		curr = next;
+	}
+
+	if (batch.nr == 1) {
+		first_key.objectid = node->inode_id;
+		first_key.type = BTRFS_DIR_INDEX_KEY;
+		first_key.offset = first_item->index;
+		batch.keys = &first_key;
+		batch.data_sizes = &first_data_size;
+	} else {
+		struct btrfs_key *ins_keys;
+		u32 *ins_sizes;
+		int i = 0;
+
+		ins_data = kmalloc(batch.nr * sizeof(u32) +
+				   batch.nr * sizeof(struct btrfs_key), GFP_NOFS);
+		if (!ins_data) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		ins_sizes = (u32 *)ins_data;
+		ins_keys = (struct btrfs_key *)(ins_data + batch.nr * sizeof(u32));
+		batch.keys = ins_keys;
+		batch.data_sizes = ins_sizes;
+		list_for_each_entry(curr, &item_list, tree_list) {
+			ins_keys[i].objectid = node->inode_id;
+			ins_keys[i].type = BTRFS_DIR_INDEX_KEY;
+			ins_keys[i].offset = curr->index;
+			ins_sizes[i] = curr->data_len;
+			i++;
+		}
+	}
+
+	ret = btrfs_insert_empty_items(trans, root, path, &batch);
+	if (ret)
+		goto out;
+
+	list_for_each_entry(curr, &item_list, tree_list) {
+		char *data_ptr;
+
+		data_ptr = btrfs_item_ptr(path->nodes[0], path->slots[0], char);
+		write_extent_buffer(path->nodes[0], &curr->data,
+				    (unsigned long)data_ptr, curr->data_len);
+		path->slots[0]++;
+	}
+
+	/*
+	 * Now release our path before releasing the delayed items and their
+	 * metadata reservations, so that we don't block other tasks for more
+	 * time than needed.
+	 */
+	btrfs_release_path(path);
+
+	ASSERT(node->index_item_leaves > 0);
+
+	/*
+	 * For normal operations we will batch an entire leaf's worth of delayed
+	 * items, so if there are more items to process we can decrement
+	 * index_item_leaves by 1 as we inserted 1 leaf's worth of items.
+	 *
+	 * However for log replay we may not have inserted an entire leaf's
+	 * worth of items, we may have not had continuous items, so decrementing
+	 * here would mess up the index_item_leaves accounting.  For this case
+	 * only clean up the accounting when there are no items left.
+	 */
+	if (next && !continuous_keys_only) {
+		/*
+		 * We inserted one batch of items into a leaf a there are more
+		 * items to flush in a future batch, now release one unit of
+		 * metadata space from the delayed block reserve, corresponding
+		 * the leaf we just flushed to.
+		 */
+		btrfs_delayed_item_release_leaves(node, 1);
+		node->index_item_leaves--;
+	} else if (!next) {
+		/*
+		 * There are no more items to insert. We can have a number of
+		 * reserved leaves > 1 here - this happens when many dir index
+		 * items are added and then removed before they are flushed (file
+		 * names with a very short life, never span a transaction). So
+		 * release all remaining leaves.
+		 */
+		btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
+		node->index_item_leaves = 0;
+	}
+
+	list_for_each_entry_safe(curr, next, &item_list, tree_list) {
+		list_del(&curr->tree_list);
+		btrfs_release_delayed_item(curr);
+	}
+out:
+	kfree(ins_data);
+	return ret;
+}
+
+static int btrfs_insert_delayed_items(struct btrfs_trans_handle *trans,
+				      struct btrfs_path *path,
+				      struct btrfs_root *root,
+				      struct btrfs_delayed_node *node)
+{
+	int ret = 0;
+
+	while (ret == 0) {
+		struct btrfs_delayed_item *curr;
+
+		mutex_lock(&node->mutex);
+		curr = __btrfs_first_delayed_insertion_item(node);
+		if (!curr) {
+			mutex_unlock(&node->mutex);
+			break;
+		}
+		ret = btrfs_insert_delayed_item(trans, root, path, curr);
+		mutex_unlock(&node->mutex);
+	}
+
+	return ret;
+}
+
+static int btrfs_batch_delete_items(struct btrfs_trans_handle *trans,
+				    struct btrfs_root *root,
+				    struct btrfs_path *path,
+				    struct btrfs_delayed_item *item)
+{
+	const u64 ino = item->delayed_node->inode_id;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_delayed_item *curr, *next;
+	struct extent_buffer *leaf = path->nodes[0];
+	LIST_HEAD(batch_list);
+	int nitems, slot, last_slot;
+	int ret;
+	u64 total_reserved_size = item->bytes_reserved;
+
+	ASSERT(leaf != NULL);
+
+	slot = path->slots[0];
+	last_slot = btrfs_header_nritems(leaf) - 1;
+	/*
+	 * Our caller always gives us a path pointing to an existing item, so
+	 * this can not happen.
+	 */
+	ASSERT(slot <= last_slot);
+	if (WARN_ON(slot > last_slot))
+		return -ENOENT;
+
+	nitems = 1;
+	curr = item;
+	list_add_tail(&curr->tree_list, &batch_list);
+
+	/*
+	 * Keep checking if the next delayed item matches the next item in the
+	 * leaf - if so, we can add it to the batch of items to delete from the
+	 * leaf.
+	 */
+	while (slot < last_slot) {
+		struct btrfs_key key;
+
+		next = __btrfs_next_delayed_item(curr);
+		if (!next)
+			break;
+
+		slot++;
+		btrfs_item_key_to_cpu(leaf, &key, slot);
+		if (key.objectid != ino ||
+		    key.type != BTRFS_DIR_INDEX_KEY ||
+		    key.offset != next->index)
+			break;
+		nitems++;
+		curr = next;
+		list_add_tail(&curr->tree_list, &batch_list);
+		total_reserved_size += curr->bytes_reserved;
+	}
+
+	ret = btrfs_del_items(trans, root, path, path->slots[0], nitems);
+	if (ret)
+		return ret;
+
+	/* In case of BTRFS_FS_LOG_RECOVERING items won't have reserved space */
+	if (total_reserved_size > 0) {
+		/*
+		 * Check btrfs_delayed_item_reserve_metadata() to see why we
+		 * don't need to release/reserve qgroup space.
+		 */
+		trace_btrfs_space_reservation(fs_info, "delayed_item", ino,
+					      total_reserved_size, 0);
+		btrfs_block_rsv_release(fs_info, &fs_info->delayed_block_rsv,
+					total_reserved_size, NULL);
+	}
+
+	list_for_each_entry_safe(curr, next, &batch_list, tree_list) {
+		list_del(&curr->tree_list);
+		btrfs_release_delayed_item(curr);
+	}
+
+	return 0;
+}
+
+static int btrfs_delete_delayed_items(struct btrfs_trans_handle *trans,
+				      struct btrfs_path *path,
+				      struct btrfs_root *root,
+				      struct btrfs_delayed_node *node)
+{
+	struct btrfs_key key;
+	int ret = 0;
+
+	key.objectid = node->inode_id;
+	key.type = BTRFS_DIR_INDEX_KEY;
+
+	while (ret == 0) {
+		struct btrfs_delayed_item *item;
+
+		mutex_lock(&node->mutex);
+		item = __btrfs_first_delayed_deletion_item(node);
+		if (!item) {
+			mutex_unlock(&node->mutex);
+			break;
+		}
+
+		key.offset = item->index;
+		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+		if (ret > 0) {
+			/*
+			 * There's no matching item in the leaf. This means we
+			 * have already deleted this item in a past run of the
+			 * delayed items. We ignore errors when running delayed
+			 * items from an async context, through a work queue job
+			 * running btrfs_async_run_delayed_root(), and don't
+			 * release delayed items that failed to complete. This
+			 * is because we will retry later, and at transaction
+			 * commit time we always run delayed items and will
+			 * then deal with errors if they fail to run again.
+			 *
+			 * So just release delayed items for which we can't find
+			 * an item in the tree, and move to the next item.
+			 */
+			btrfs_release_path(path);
+			btrfs_release_delayed_item(item);
+			ret = 0;
+		} else if (ret == 0) {
+			ret = btrfs_batch_delete_items(trans, root, path, item);
+			btrfs_release_path(path);
+		}
+
+		/*
+		 * We unlock and relock on each iteration, this is to prevent
+		 * blocking other tasks for too long while we are being run from
+		 * the async context (work queue job). Those tasks are typically
+		 * running system calls like creat/mkdir/rename/unlink/etc which
+		 * need to add delayed items to this delayed node.
+		 */
+		mutex_unlock(&node->mutex);
+	}
+
+	return ret;
+}
+
+static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
+{
+	struct btrfs_delayed_root *delayed_root;
+
+	if (delayed_node &&
+	    test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
+		BUG_ON(!delayed_node->root);
+		clear_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
+		delayed_node->count--;
+
+		delayed_root = delayed_node->root->fs_info->delayed_root;
+		finish_one_item(delayed_root);
+	}
+}
+
+static void btrfs_release_delayed_iref(struct btrfs_delayed_node *delayed_node)
+{
+
+	if (test_and_clear_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags)) {
+		struct btrfs_delayed_root *delayed_root;
+
+		ASSERT(delayed_node->root);
+		delayed_node->count--;
+
+		delayed_root = delayed_node->root->fs_info->delayed_root;
+		finish_one_item(delayed_root);
+	}
+}
+
+static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
+					struct btrfs_root *root,
+					struct btrfs_path *path,
+					struct btrfs_delayed_node *node)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_key key;
+	struct btrfs_inode_item *inode_item;
+	struct extent_buffer *leaf;
+	int mod;
+	int ret;
+
+	key.objectid = node->inode_id;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+
+	if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
+		mod = -1;
+	else
+		mod = 1;
+
+	ret = btrfs_lookup_inode(trans, root, path, &key, mod);
+	if (ret > 0)
+		ret = -ENOENT;
+	if (ret < 0)
+		goto out;
+
+	leaf = path->nodes[0];
+	inode_item = btrfs_item_ptr(leaf, path->slots[0],
+				    struct btrfs_inode_item);
+	write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
+			    sizeof(struct btrfs_inode_item));
+	btrfs_mark_buffer_dirty(trans, leaf);
+
+	if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
+		goto out;
+
+	path->slots[0]++;
+	if (path->slots[0] >= btrfs_header_nritems(leaf))
+		goto search;
+again:
+	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+	if (key.objectid != node->inode_id)
+		goto out;
+
+	if (key.type != BTRFS_INODE_REF_KEY &&
+	    key.type != BTRFS_INODE_EXTREF_KEY)
+		goto out;
+
+	/*
+	 * Delayed iref deletion is for the inode who has only one link,
+	 * so there is only one iref. The case that several irefs are
+	 * in the same item doesn't exist.
+	 */
+	ret = btrfs_del_item(trans, root, path);
+out:
+	btrfs_release_delayed_iref(node);
+	btrfs_release_path(path);
+err_out:
+	btrfs_delayed_inode_release_metadata(fs_info, node, (ret < 0));
+	btrfs_release_delayed_inode(node);
+
+	/*
+	 * If we fail to update the delayed inode we need to abort the
+	 * transaction, because we could leave the inode with the improper
+	 * counts behind.
+	 */
+	if (ret && ret != -ENOENT)
+		btrfs_abort_transaction(trans, ret);
+
+	return ret;
+
+search:
+	btrfs_release_path(path);
+
+	key.type = BTRFS_INODE_EXTREF_KEY;
+	key.offset = -1;
+
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret < 0)
+		goto err_out;
+	ASSERT(ret);
+
+	ret = 0;
+	leaf = path->nodes[0];
+	path->slots[0]--;
+	goto again;
+}
+
+static inline int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
+					     struct btrfs_root *root,
+					     struct btrfs_path *path,
+					     struct btrfs_delayed_node *node)
+{
+	int ret;
+
+	mutex_lock(&node->mutex);
+	if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &node->flags)) {
+		mutex_unlock(&node->mutex);
+		return 0;
+	}
+
+	ret = __btrfs_update_delayed_inode(trans, root, path, node);
+	mutex_unlock(&node->mutex);
+	return ret;
+}
+
+static inline int
+__btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
+				   struct btrfs_path *path,
+				   struct btrfs_delayed_node *node)
+{
+	int ret;
+
+	ret = btrfs_insert_delayed_items(trans, path, node->root, node);
+	if (ret)
+		return ret;
+
+	ret = btrfs_delete_delayed_items(trans, path, node->root, node);
+	if (ret)
+		return ret;
+
+	ret = btrfs_update_delayed_inode(trans, node->root, path, node);
+	return ret;
+}
+
+/*
+ * Called when committing the transaction.
+ * Returns 0 on success.
+ * Returns < 0 on error and returns with an aborted transaction with any
+ * outstanding delayed items cleaned up.
+ */
+static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	struct btrfs_delayed_root *delayed_root;
+	struct btrfs_delayed_node *curr_node, *prev_node;
+	struct btrfs_path *path;
+	struct btrfs_block_rsv *block_rsv;
+	int ret = 0;
+	bool count = (nr > 0);
+
+	if (TRANS_ABORTED(trans))
+		return -EIO;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	block_rsv = trans->block_rsv;
+	trans->block_rsv = &fs_info->delayed_block_rsv;
+
+	delayed_root = fs_info->delayed_root;
+
+	curr_node = btrfs_first_delayed_node(delayed_root);
+	while (curr_node && (!count || nr--)) {
+		ret = __btrfs_commit_inode_delayed_items(trans, path,
+							 curr_node);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			break;
+		}
+
+		prev_node = curr_node;
+		curr_node = btrfs_next_delayed_node(curr_node);
+		/*
+		 * See the comment below about releasing path before releasing
+		 * node. If the commit of delayed items was successful the path
+		 * should always be released, but in case of an error, it may
+		 * point to locked extent buffers (a leaf at the very least).
+		 */
+		ASSERT(path->nodes[0] == NULL);
+		btrfs_release_delayed_node(prev_node);
+	}
+
+	/*
+	 * Release the path to avoid a potential deadlock and lockdep splat when
+	 * releasing the delayed node, as that requires taking the delayed node's
+	 * mutex. If another task starts running delayed items before we take
+	 * the mutex, it will first lock the mutex and then it may try to lock
+	 * the same btree path (leaf).
+	 */
+	btrfs_free_path(path);
+
+	if (curr_node)
+		btrfs_release_delayed_node(curr_node);
+	trans->block_rsv = block_rsv;
+
+	return ret;
+}
+
+int btrfs_run_delayed_items(struct btrfs_trans_handle *trans)
+{
+	return __btrfs_run_delayed_items(trans, -1);
+}
+
+int btrfs_run_delayed_items_nr(struct btrfs_trans_handle *trans, int nr)
+{
+	return __btrfs_run_delayed_items(trans, nr);
+}
+
+int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
+				     struct btrfs_inode *inode)
+{
+	struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
+	struct btrfs_path *path;
+	struct btrfs_block_rsv *block_rsv;
+	int ret;
+
+	if (!delayed_node)
+		return 0;
+
+	mutex_lock(&delayed_node->mutex);
+	if (!delayed_node->count) {
+		mutex_unlock(&delayed_node->mutex);
+		btrfs_release_delayed_node(delayed_node);
+		return 0;
+	}
+	mutex_unlock(&delayed_node->mutex);
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		btrfs_release_delayed_node(delayed_node);
+		return -ENOMEM;
+	}
+
+	block_rsv = trans->block_rsv;
+	trans->block_rsv = &delayed_node->root->fs_info->delayed_block_rsv;
+
+	ret = __btrfs_commit_inode_delayed_items(trans, path, delayed_node);
+
+	btrfs_release_delayed_node(delayed_node);
+	btrfs_free_path(path);
+	trans->block_rsv = block_rsv;
+
+	return ret;
+}
+
+int btrfs_commit_inode_delayed_inode(struct btrfs_inode *inode)
+{
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
+	struct btrfs_path *path;
+	struct btrfs_block_rsv *block_rsv;
+	int ret;
+
+	if (!delayed_node)
+		return 0;
+
+	mutex_lock(&delayed_node->mutex);
+	if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
+		mutex_unlock(&delayed_node->mutex);
+		btrfs_release_delayed_node(delayed_node);
+		return 0;
+	}
+	mutex_unlock(&delayed_node->mutex);
+
+	trans = btrfs_join_transaction(delayed_node->root);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		goto out;
+	}
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		ret = -ENOMEM;
+		goto trans_out;
+	}
+
+	block_rsv = trans->block_rsv;
+	trans->block_rsv = &fs_info->delayed_block_rsv;
+
+	mutex_lock(&delayed_node->mutex);
+	if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags))
+		ret = __btrfs_update_delayed_inode(trans, delayed_node->root,
+						   path, delayed_node);
+	else
+		ret = 0;
+	mutex_unlock(&delayed_node->mutex);
+
+	btrfs_free_path(path);
+	trans->block_rsv = block_rsv;
+trans_out:
+	btrfs_end_transaction(trans);
+	btrfs_btree_balance_dirty(fs_info);
+out:
+	btrfs_release_delayed_node(delayed_node);
+
+	return ret;
+}
+
+void btrfs_remove_delayed_node(struct btrfs_inode *inode)
+{
+	struct btrfs_delayed_node *delayed_node;
+
+	delayed_node = READ_ONCE(inode->delayed_node);
+	if (!delayed_node)
+		return;
+
+	inode->delayed_node = NULL;
+	btrfs_release_delayed_node(delayed_node);
+}
+
+struct btrfs_async_delayed_work {
+	struct btrfs_delayed_root *delayed_root;
+	int nr;
+	struct btrfs_work work;
+};
+
+static void btrfs_async_run_delayed_root(struct btrfs_work *work)
+{
+	struct btrfs_async_delayed_work *async_work;
+	struct btrfs_delayed_root *delayed_root;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_path *path;
+	struct btrfs_delayed_node *delayed_node = NULL;
+	struct btrfs_root *root;
+	struct btrfs_block_rsv *block_rsv;
+	int total_done = 0;
+
+	async_work = container_of(work, struct btrfs_async_delayed_work, work);
+	delayed_root = async_work->delayed_root;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		goto out;
+
+	do {
+		if (atomic_read(&delayed_root->items) <
+		    BTRFS_DELAYED_BACKGROUND / 2)
+			break;
+
+		delayed_node = btrfs_first_prepared_delayed_node(delayed_root);
+		if (!delayed_node)
+			break;
+
+		root = delayed_node->root;
+
+		trans = btrfs_join_transaction(root);
+		if (IS_ERR(trans)) {
+			btrfs_release_path(path);
+			btrfs_release_prepared_delayed_node(delayed_node);
+			total_done++;
+			continue;
+		}
+
+		block_rsv = trans->block_rsv;
+		trans->block_rsv = &root->fs_info->delayed_block_rsv;
+
+		__btrfs_commit_inode_delayed_items(trans, path, delayed_node);
+
+		trans->block_rsv = block_rsv;
+		btrfs_end_transaction(trans);
+		btrfs_btree_balance_dirty_nodelay(root->fs_info);
+
+		btrfs_release_path(path);
+		btrfs_release_prepared_delayed_node(delayed_node);
+		total_done++;
+
+	} while ((async_work->nr == 0 && total_done < BTRFS_DELAYED_WRITEBACK)
+		 || total_done < async_work->nr);
+
+	btrfs_free_path(path);
+out:
+	wake_up(&delayed_root->wait);
+	kfree(async_work);
+}
+
+
+static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
+				     struct btrfs_fs_info *fs_info, int nr)
+{
+	struct btrfs_async_delayed_work *async_work;
+
+	async_work = kmalloc(sizeof(*async_work), GFP_NOFS);
+	if (!async_work)
+		return -ENOMEM;
+
+	async_work->delayed_root = delayed_root;
+	btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root, NULL,
+			NULL);
+	async_work->nr = nr;
+
+	btrfs_queue_work(fs_info->delayed_workers, &async_work->work);
+	return 0;
+}
+
+void btrfs_assert_delayed_root_empty(struct btrfs_fs_info *fs_info)
+{
+	WARN_ON(btrfs_first_delayed_node(fs_info->delayed_root));
+}
+
+static int could_end_wait(struct btrfs_delayed_root *delayed_root, int seq)
+{
+	int val = atomic_read(&delayed_root->items_seq);
+
+	if (val < seq || val >= seq + BTRFS_DELAYED_BATCH)
+		return 1;
+
+	if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
+		return 1;
+
+	return 0;
+}
+
+void btrfs_balance_delayed_items(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_delayed_root *delayed_root = fs_info->delayed_root;
+
+	if ((atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND) ||
+		btrfs_workqueue_normal_congested(fs_info->delayed_workers))
+		return;
+
+	if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
+		int seq;
+		int ret;
+
+		seq = atomic_read(&delayed_root->items_seq);
+
+		ret = btrfs_wq_run_delayed_node(delayed_root, fs_info, 0);
+		if (ret)
+			return;
+
+		wait_event_interruptible(delayed_root->wait,
+					 could_end_wait(delayed_root, seq));
+		return;
+	}
+
+	btrfs_wq_run_delayed_node(delayed_root, fs_info, BTRFS_DELAYED_BATCH);
+}
+
+static void btrfs_release_dir_index_item_space(struct btrfs_trans_handle *trans)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
+
+	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
+		return;
+
+	/*
+	 * Adding the new dir index item does not require touching another
+	 * leaf, so we can release 1 unit of metadata that was previously
+	 * reserved when starting the transaction. This applies only to
+	 * the case where we had a transaction start and excludes the
+	 * transaction join case (when replaying log trees).
+	 */
+	trace_btrfs_space_reservation(fs_info, "transaction",
+				      trans->transid, bytes, 0);
+	btrfs_block_rsv_release(fs_info, trans->block_rsv, bytes, NULL);
+	ASSERT(trans->bytes_reserved >= bytes);
+	trans->bytes_reserved -= bytes;
+}
+
+/* Will return 0, -ENOMEM or -EEXIST (index number collision, unexpected). */
+int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
+				   const char *name, int name_len,
+				   struct btrfs_inode *dir,
+				   struct btrfs_disk_key *disk_key, u8 flags,
+				   u64 index)
+{
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	const unsigned int leaf_data_size = BTRFS_LEAF_DATA_SIZE(fs_info);
+	struct btrfs_delayed_node *delayed_node;
+	struct btrfs_delayed_item *delayed_item;
+	struct btrfs_dir_item *dir_item;
+	bool reserve_leaf_space;
+	u32 data_len;
+	int ret;
+
+	delayed_node = btrfs_get_or_create_delayed_node(dir);
+	if (IS_ERR(delayed_node))
+		return PTR_ERR(delayed_node);
+
+	delayed_item = btrfs_alloc_delayed_item(sizeof(*dir_item) + name_len,
+						delayed_node,
+						BTRFS_DELAYED_INSERTION_ITEM);
+	if (!delayed_item) {
+		ret = -ENOMEM;
+		goto release_node;
+	}
+
+	delayed_item->index = index;
+
+	dir_item = (struct btrfs_dir_item *)delayed_item->data;
+	dir_item->location = *disk_key;
+	btrfs_set_stack_dir_transid(dir_item, trans->transid);
+	btrfs_set_stack_dir_data_len(dir_item, 0);
+	btrfs_set_stack_dir_name_len(dir_item, name_len);
+	btrfs_set_stack_dir_flags(dir_item, flags);
+	memcpy((char *)(dir_item + 1), name, name_len);
+
+	data_len = delayed_item->data_len + sizeof(struct btrfs_item);
+
+	mutex_lock(&delayed_node->mutex);
+
+	/*
+	 * First attempt to insert the delayed item. This is to make the error
+	 * handling path simpler in case we fail (-EEXIST). There's no risk of
+	 * any other task coming in and running the delayed item before we do
+	 * the metadata space reservation below, because we are holding the
+	 * delayed node's mutex and that mutex must also be locked before the
+	 * node's delayed items can be run.
+	 */
+	ret = __btrfs_add_delayed_item(delayed_node, delayed_item);
+	if (unlikely(ret)) {
+		btrfs_err(trans->fs_info,
+"error adding delayed dir index item, name: %.*s, index: %llu, root: %llu, dir: %llu, dir->index_cnt: %llu, delayed_node->index_cnt: %llu, error: %d",
+			  name_len, name, index, btrfs_root_id(delayed_node->root),
+			  delayed_node->inode_id, dir->index_cnt,
+			  delayed_node->index_cnt, ret);
+		btrfs_release_delayed_item(delayed_item);
+		btrfs_release_dir_index_item_space(trans);
+		mutex_unlock(&delayed_node->mutex);
+		goto release_node;
+	}
+
+	if (delayed_node->index_item_leaves == 0 ||
+	    delayed_node->curr_index_batch_size + data_len > leaf_data_size) {
+		delayed_node->curr_index_batch_size = data_len;
+		reserve_leaf_space = true;
+	} else {
+		delayed_node->curr_index_batch_size += data_len;
+		reserve_leaf_space = false;
+	}
+
+	if (reserve_leaf_space) {
+		ret = btrfs_delayed_item_reserve_metadata(trans, delayed_item);
+		/*
+		 * Space was reserved for a dir index item insertion when we
+		 * started the transaction, so getting a failure here should be
+		 * impossible.
+		 */
+		if (WARN_ON(ret)) {
+			btrfs_release_delayed_item(delayed_item);
+			mutex_unlock(&delayed_node->mutex);
+			goto release_node;
+		}
+
+		delayed_node->index_item_leaves++;
+	} else {
+		btrfs_release_dir_index_item_space(trans);
+	}
+	mutex_unlock(&delayed_node->mutex);
+
+release_node:
+	btrfs_release_delayed_node(delayed_node);
+	return ret;
+}
+
+static int btrfs_delete_delayed_insertion_item(struct btrfs_fs_info *fs_info,
+					       struct btrfs_delayed_node *node,
+					       u64 index)
+{
+	struct btrfs_delayed_item *item;
+
+	mutex_lock(&node->mutex);
+	item = __btrfs_lookup_delayed_item(&node->ins_root.rb_root, index);
+	if (!item) {
+		mutex_unlock(&node->mutex);
+		return 1;
+	}
+
+	/*
+	 * For delayed items to insert, we track reserved metadata bytes based
+	 * on the number of leaves that we will use.
+	 * See btrfs_insert_delayed_dir_index() and
+	 * btrfs_delayed_item_reserve_metadata()).
+	 */
+	ASSERT(item->bytes_reserved == 0);
+	ASSERT(node->index_item_leaves > 0);
+
+	/*
+	 * If there's only one leaf reserved, we can decrement this item from the
+	 * current batch, otherwise we can not because we don't know which leaf
+	 * it belongs to. With the current limit on delayed items, we rarely
+	 * accumulate enough dir index items to fill more than one leaf (even
+	 * when using a leaf size of 4K).
+	 */
+	if (node->index_item_leaves == 1) {
+		const u32 data_len = item->data_len + sizeof(struct btrfs_item);
+
+		ASSERT(node->curr_index_batch_size >= data_len);
+		node->curr_index_batch_size -= data_len;
+	}
+
+	btrfs_release_delayed_item(item);
+
+	/* If we now have no more dir index items, we can release all leaves. */
+	if (RB_EMPTY_ROOT(&node->ins_root.rb_root)) {
+		btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
+		node->index_item_leaves = 0;
+	}
+
+	mutex_unlock(&node->mutex);
+	return 0;
+}
+
+int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
+				   struct btrfs_inode *dir, u64 index)
+{
+	struct btrfs_delayed_node *node;
+	struct btrfs_delayed_item *item;
+	int ret;
+
+	node = btrfs_get_or_create_delayed_node(dir);
+	if (IS_ERR(node))
+		return PTR_ERR(node);
+
+	ret = btrfs_delete_delayed_insertion_item(trans->fs_info, node, index);
+	if (!ret)
+		goto end;
+
+	item = btrfs_alloc_delayed_item(0, node, BTRFS_DELAYED_DELETION_ITEM);
+	if (!item) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	item->index = index;
+
+	ret = btrfs_delayed_item_reserve_metadata(trans, item);
+	/*
+	 * we have reserved enough space when we start a new transaction,
+	 * so reserving metadata failure is impossible.
+	 */
+	if (ret < 0) {
+		btrfs_err(trans->fs_info,
+"metadata reservation failed for delayed dir item deltiona, should have been reserved");
+		btrfs_release_delayed_item(item);
+		goto end;
+	}
+
+	mutex_lock(&node->mutex);
+	ret = __btrfs_add_delayed_item(node, item);
+	if (unlikely(ret)) {
+		btrfs_err(trans->fs_info,
+			  "err add delayed dir index item(index: %llu) into the deletion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
+			  index, node->root->root_key.objectid,
+			  node->inode_id, ret);
+		btrfs_delayed_item_release_metadata(dir->root, item);
+		btrfs_release_delayed_item(item);
+	}
+	mutex_unlock(&node->mutex);
+end:
+	btrfs_release_delayed_node(node);
+	return ret;
+}
+
+int btrfs_inode_delayed_dir_index_count(struct btrfs_inode *inode)
+{
+	struct btrfs_delayed_node *delayed_node = btrfs_get_delayed_node(inode);
+
+	if (!delayed_node)
+		return -ENOENT;
+
+	/*
+	 * Since we have held i_mutex of this directory, it is impossible that
+	 * a new directory index is added into the delayed node and index_cnt
+	 * is updated now. So we needn't lock the delayed node.
+	 */
+	if (!delayed_node->index_cnt) {
+		btrfs_release_delayed_node(delayed_node);
+		return -EINVAL;
+	}
+
+	inode->index_cnt = delayed_node->index_cnt;
+	btrfs_release_delayed_node(delayed_node);
+	return 0;
+}
+
+bool btrfs_readdir_get_delayed_items(struct inode *inode,
+				     u64 last_index,
+				     struct list_head *ins_list,
+				     struct list_head *del_list)
+{
+	struct btrfs_delayed_node *delayed_node;
+	struct btrfs_delayed_item *item;
+
+	delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
+	if (!delayed_node)
+		return false;
+
+	/*
+	 * We can only do one readdir with delayed items at a time because of
+	 * item->readdir_list.
+	 */
+	btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
+	btrfs_inode_lock(BTRFS_I(inode), 0);
+
+	mutex_lock(&delayed_node->mutex);
+	item = __btrfs_first_delayed_insertion_item(delayed_node);
+	while (item && item->index <= last_index) {
+		refcount_inc(&item->refs);
+		list_add_tail(&item->readdir_list, ins_list);
+		item = __btrfs_next_delayed_item(item);
+	}
+
+	item = __btrfs_first_delayed_deletion_item(delayed_node);
+	while (item && item->index <= last_index) {
+		refcount_inc(&item->refs);
+		list_add_tail(&item->readdir_list, del_list);
+		item = __btrfs_next_delayed_item(item);
+	}
+	mutex_unlock(&delayed_node->mutex);
+	/*
+	 * This delayed node is still cached in the btrfs inode, so refs
+	 * must be > 1 now, and we needn't check it is going to be freed
+	 * or not.
+	 *
+	 * Besides that, this function is used to read dir, we do not
+	 * insert/delete delayed items in this period. So we also needn't
+	 * requeue or dequeue this delayed node.
+	 */
+	refcount_dec(&delayed_node->refs);
+
+	return true;
+}
+
+void btrfs_readdir_put_delayed_items(struct inode *inode,
+				     struct list_head *ins_list,
+				     struct list_head *del_list)
+{
+	struct btrfs_delayed_item *curr, *next;
+
+	list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
+		list_del(&curr->readdir_list);
+		if (refcount_dec_and_test(&curr->refs))
+			kfree(curr);
+	}
+
+	list_for_each_entry_safe(curr, next, del_list, readdir_list) {
+		list_del(&curr->readdir_list);
+		if (refcount_dec_and_test(&curr->refs))
+			kfree(curr);
+	}
+
+	/*
+	 * The VFS is going to do up_read(), so we need to downgrade back to a
+	 * read lock.
+	 */
+	downgrade_write(&inode->i_rwsem);
+}
+
+int btrfs_should_delete_dir_index(struct list_head *del_list,
+				  u64 index)
+{
+	struct btrfs_delayed_item *curr;
+	int ret = 0;
+
+	list_for_each_entry(curr, del_list, readdir_list) {
+		if (curr->index > index)
+			break;
+		if (curr->index == index) {
+			ret = 1;
+			break;
+		}
+	}
+	return ret;
+}
+
+/*
+ * btrfs_readdir_delayed_dir_index - read dir info stored in the delayed tree
+ *
+ */
+int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
+				    struct list_head *ins_list)
+{
+	struct btrfs_dir_item *di;
+	struct btrfs_delayed_item *curr, *next;
+	struct btrfs_key location;
+	char *name;
+	int name_len;
+	int over = 0;
+	unsigned char d_type;
+
+	/*
+	 * Changing the data of the delayed item is impossible. So
+	 * we needn't lock them. And we have held i_mutex of the
+	 * directory, nobody can delete any directory indexes now.
+	 */
+	list_for_each_entry_safe(curr, next, ins_list, readdir_list) {
+		list_del(&curr->readdir_list);
+
+		if (curr->index < ctx->pos) {
+			if (refcount_dec_and_test(&curr->refs))
+				kfree(curr);
+			continue;
+		}
+
+		ctx->pos = curr->index;
+
+		di = (struct btrfs_dir_item *)curr->data;
+		name = (char *)(di + 1);
+		name_len = btrfs_stack_dir_name_len(di);
+
+		d_type = fs_ftype_to_dtype(btrfs_dir_flags_to_ftype(di->type));
+		btrfs_disk_key_to_cpu(&location, &di->location);
+
+		over = !dir_emit(ctx, name, name_len,
+			       location.objectid, d_type);
+
+		if (refcount_dec_and_test(&curr->refs))
+			kfree(curr);
+
+		if (over)
+			return 1;
+		ctx->pos++;
+	}
+	return 0;
+}
+
+static void fill_stack_inode_item(struct btrfs_trans_handle *trans,
+				  struct btrfs_inode_item *inode_item,
+				  struct inode *inode)
+{
+	u64 flags;
+
+	btrfs_set_stack_inode_uid(inode_item, i_uid_read(inode));
+	btrfs_set_stack_inode_gid(inode_item, i_gid_read(inode));
+	btrfs_set_stack_inode_size(inode_item, BTRFS_I(inode)->disk_i_size);
+	btrfs_set_stack_inode_mode(inode_item, inode->i_mode);
+	btrfs_set_stack_inode_nlink(inode_item, inode->i_nlink);
+	btrfs_set_stack_inode_nbytes(inode_item, inode_get_bytes(inode));
+	btrfs_set_stack_inode_generation(inode_item,
+					 BTRFS_I(inode)->generation);
+	btrfs_set_stack_inode_sequence(inode_item,
+				       inode_peek_iversion(inode));
+	btrfs_set_stack_inode_transid(inode_item, trans->transid);
+	btrfs_set_stack_inode_rdev(inode_item, inode->i_rdev);
+	flags = btrfs_inode_combine_flags(BTRFS_I(inode)->flags,
+					  BTRFS_I(inode)->ro_flags);
+	btrfs_set_stack_inode_flags(inode_item, flags);
+	btrfs_set_stack_inode_block_group(inode_item, 0);
+
+	btrfs_set_stack_timespec_sec(&inode_item->atime,
+				     inode->i_atime.tv_sec);
+	btrfs_set_stack_timespec_nsec(&inode_item->atime,
+				      inode->i_atime.tv_nsec);
+
+	btrfs_set_stack_timespec_sec(&inode_item->mtime,
+				     inode->i_mtime.tv_sec);
+	btrfs_set_stack_timespec_nsec(&inode_item->mtime,
+				      inode->i_mtime.tv_nsec);
+
+	btrfs_set_stack_timespec_sec(&inode_item->ctime,
+				     inode_get_ctime(inode).tv_sec);
+	btrfs_set_stack_timespec_nsec(&inode_item->ctime,
+				      inode_get_ctime(inode).tv_nsec);
+
+	btrfs_set_stack_timespec_sec(&inode_item->otime,
+				     BTRFS_I(inode)->i_otime.tv_sec);
+	btrfs_set_stack_timespec_nsec(&inode_item->otime,
+				     BTRFS_I(inode)->i_otime.tv_nsec);
+}
+
+int btrfs_fill_inode(struct inode *inode, u32 *rdev)
+{
+	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
+	struct btrfs_delayed_node *delayed_node;
+	struct btrfs_inode_item *inode_item;
+
+	delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
+	if (!delayed_node)
+		return -ENOENT;
+
+	mutex_lock(&delayed_node->mutex);
+	if (!test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
+		mutex_unlock(&delayed_node->mutex);
+		btrfs_release_delayed_node(delayed_node);
+		return -ENOENT;
+	}
+
+	inode_item = &delayed_node->inode_item;
+
+	i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
+	i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
+	btrfs_i_size_write(BTRFS_I(inode), btrfs_stack_inode_size(inode_item));
+	btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
+			round_up(i_size_read(inode), fs_info->sectorsize));
+	inode->i_mode = btrfs_stack_inode_mode(inode_item);
+	set_nlink(inode, btrfs_stack_inode_nlink(inode_item));
+	inode_set_bytes(inode, btrfs_stack_inode_nbytes(inode_item));
+	BTRFS_I(inode)->generation = btrfs_stack_inode_generation(inode_item);
+        BTRFS_I(inode)->last_trans = btrfs_stack_inode_transid(inode_item);
+
+	inode_set_iversion_queried(inode,
+				   btrfs_stack_inode_sequence(inode_item));
+	inode->i_rdev = 0;
+	*rdev = btrfs_stack_inode_rdev(inode_item);
+	btrfs_inode_split_flags(btrfs_stack_inode_flags(inode_item),
+				&BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags);
+
+	inode->i_atime.tv_sec = btrfs_stack_timespec_sec(&inode_item->atime);
+	inode->i_atime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->atime);
+
+	inode->i_mtime.tv_sec = btrfs_stack_timespec_sec(&inode_item->mtime);
+	inode->i_mtime.tv_nsec = btrfs_stack_timespec_nsec(&inode_item->mtime);
+
+	inode_set_ctime(inode, btrfs_stack_timespec_sec(&inode_item->ctime),
+			btrfs_stack_timespec_nsec(&inode_item->ctime));
+
+	BTRFS_I(inode)->i_otime.tv_sec =
+		btrfs_stack_timespec_sec(&inode_item->otime);
+	BTRFS_I(inode)->i_otime.tv_nsec =
+		btrfs_stack_timespec_nsec(&inode_item->otime);
+
+	inode->i_generation = BTRFS_I(inode)->generation;
+	BTRFS_I(inode)->index_cnt = (u64)-1;
+
+	mutex_unlock(&delayed_node->mutex);
+	btrfs_release_delayed_node(delayed_node);
+	return 0;
+}
+
+int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root,
+			       struct btrfs_inode *inode)
+{
+	struct btrfs_delayed_node *delayed_node;
+	int ret = 0;
+
+	delayed_node = btrfs_get_or_create_delayed_node(inode);
+	if (IS_ERR(delayed_node))
+		return PTR_ERR(delayed_node);
+
+	mutex_lock(&delayed_node->mutex);
+	if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
+		fill_stack_inode_item(trans, &delayed_node->inode_item,
+				      &inode->vfs_inode);
+		goto release_node;
+	}
+
+	ret = btrfs_delayed_inode_reserve_metadata(trans, root, delayed_node);
+	if (ret)
+		goto release_node;
+
+	fill_stack_inode_item(trans, &delayed_node->inode_item, &inode->vfs_inode);
+	set_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags);
+	delayed_node->count++;
+	atomic_inc(&root->fs_info->delayed_root->items);
+release_node:
+	mutex_unlock(&delayed_node->mutex);
+	btrfs_release_delayed_node(delayed_node);
+	return ret;
+}
+
+int btrfs_delayed_delete_inode_ref(struct btrfs_inode *inode)
+{
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
+	struct btrfs_delayed_node *delayed_node;
+
+	/*
+	 * we don't do delayed inode updates during log recovery because it
+	 * leads to enospc problems.  This means we also can't do
+	 * delayed inode refs
+	 */
+	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
+		return -EAGAIN;
+
+	delayed_node = btrfs_get_or_create_delayed_node(inode);
+	if (IS_ERR(delayed_node))
+		return PTR_ERR(delayed_node);
+
+	/*
+	 * We don't reserve space for inode ref deletion is because:
+	 * - We ONLY do async inode ref deletion for the inode who has only
+	 *   one link(i_nlink == 1), it means there is only one inode ref.
+	 *   And in most case, the inode ref and the inode item are in the
+	 *   same leaf, and we will deal with them at the same time.
+	 *   Since we are sure we will reserve the space for the inode item,
+	 *   it is unnecessary to reserve space for inode ref deletion.
+	 * - If the inode ref and the inode item are not in the same leaf,
+	 *   We also needn't worry about enospc problem, because we reserve
+	 *   much more space for the inode update than it needs.
+	 * - At the worst, we can steal some space from the global reservation.
+	 *   It is very rare.
+	 */
+	mutex_lock(&delayed_node->mutex);
+	if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags))
+		goto release_node;
+
+	set_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags);
+	delayed_node->count++;
+	atomic_inc(&fs_info->delayed_root->items);
+release_node:
+	mutex_unlock(&delayed_node->mutex);
+	btrfs_release_delayed_node(delayed_node);
+	return 0;
+}
+
+static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
+{
+	struct btrfs_root *root = delayed_node->root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_delayed_item *curr_item, *prev_item;
+
+	mutex_lock(&delayed_node->mutex);
+	curr_item = __btrfs_first_delayed_insertion_item(delayed_node);
+	while (curr_item) {
+		prev_item = curr_item;
+		curr_item = __btrfs_next_delayed_item(prev_item);
+		btrfs_release_delayed_item(prev_item);
+	}
+
+	if (delayed_node->index_item_leaves > 0) {
+		btrfs_delayed_item_release_leaves(delayed_node,
+					  delayed_node->index_item_leaves);
+		delayed_node->index_item_leaves = 0;
+	}
+
+	curr_item = __btrfs_first_delayed_deletion_item(delayed_node);
+	while (curr_item) {
+		btrfs_delayed_item_release_metadata(root, curr_item);
+		prev_item = curr_item;
+		curr_item = __btrfs_next_delayed_item(prev_item);
+		btrfs_release_delayed_item(prev_item);
+	}
+
+	btrfs_release_delayed_iref(delayed_node);
+
+	if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
+		btrfs_delayed_inode_release_metadata(fs_info, delayed_node, false);
+		btrfs_release_delayed_inode(delayed_node);
+	}
+	mutex_unlock(&delayed_node->mutex);
+}
+
+void btrfs_kill_delayed_inode_items(struct btrfs_inode *inode)
+{
+	struct btrfs_delayed_node *delayed_node;
+
+	delayed_node = btrfs_get_delayed_node(inode);
+	if (!delayed_node)
+		return;
+
+	__btrfs_kill_delayed_node(delayed_node);
+	btrfs_release_delayed_node(delayed_node);
+}
+
+void btrfs_kill_all_delayed_nodes(struct btrfs_root *root)
+{
+	u64 inode_id = 0;
+	struct btrfs_delayed_node *delayed_nodes[8];
+	int i, n;
+
+	while (1) {
+		spin_lock(&root->inode_lock);
+		n = radix_tree_gang_lookup(&root->delayed_nodes_tree,
+					   (void **)delayed_nodes, inode_id,
+					   ARRAY_SIZE(delayed_nodes));
+		if (!n) {
+			spin_unlock(&root->inode_lock);
+			break;
+		}
+
+		inode_id = delayed_nodes[n - 1]->inode_id + 1;
+		for (i = 0; i < n; i++) {
+			/*
+			 * Don't increase refs in case the node is dead and
+			 * about to be removed from the tree in the loop below
+			 */
+			if (!refcount_inc_not_zero(&delayed_nodes[i]->refs))
+				delayed_nodes[i] = NULL;
+		}
+		spin_unlock(&root->inode_lock);
+
+		for (i = 0; i < n; i++) {
+			if (!delayed_nodes[i])
+				continue;
+			__btrfs_kill_delayed_node(delayed_nodes[i]);
+			btrfs_release_delayed_node(delayed_nodes[i]);
+		}
+	}
+}
+
+void btrfs_destroy_delayed_inodes(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_delayed_node *curr_node, *prev_node;
+
+	curr_node = btrfs_first_delayed_node(fs_info->delayed_root);
+	while (curr_node) {
+		__btrfs_kill_delayed_node(curr_node);
+
+		prev_node = curr_node;
+		curr_node = btrfs_next_delayed_node(curr_node);
+		btrfs_release_delayed_node(prev_node);
+	}
+}
+
+void btrfs_log_get_delayed_items(struct btrfs_inode *inode,
+				 struct list_head *ins_list,
+				 struct list_head *del_list)
+{
+	struct btrfs_delayed_node *node;
+	struct btrfs_delayed_item *item;
+
+	node = btrfs_get_delayed_node(inode);
+	if (!node)
+		return;
+
+	mutex_lock(&node->mutex);
+	item = __btrfs_first_delayed_insertion_item(node);
+	while (item) {
+		/*
+		 * It's possible that the item is already in a log list. This
+		 * can happen in case two tasks are trying to log the same
+		 * directory. For example if we have tasks A and task B:
+		 *
+		 * Task A collected the delayed items into a log list while
+		 * under the inode's log_mutex (at btrfs_log_inode()), but it
+		 * only releases the items after logging the inodes they point
+		 * to (if they are new inodes), which happens after unlocking
+		 * the log mutex;
+		 *
+		 * Task B enters btrfs_log_inode() and acquires the log_mutex
+		 * of the same directory inode, before task B releases the
+		 * delayed items. This can happen for example when logging some
+		 * inode we need to trigger logging of its parent directory, so
+		 * logging two files that have the same parent directory can
+		 * lead to this.
+		 *
+		 * If this happens, just ignore delayed items already in a log
+		 * list. All the tasks logging the directory are under a log
+		 * transaction and whichever finishes first can not sync the log
+		 * before the other completes and leaves the log transaction.
+		 */
+		if (!item->logged && list_empty(&item->log_list)) {
+			refcount_inc(&item->refs);
+			list_add_tail(&item->log_list, ins_list);
+		}
+		item = __btrfs_next_delayed_item(item);
+	}
+
+	item = __btrfs_first_delayed_deletion_item(node);
+	while (item) {
+		/* It may be non-empty, for the same reason mentioned above. */
+		if (!item->logged && list_empty(&item->log_list)) {
+			refcount_inc(&item->refs);
+			list_add_tail(&item->log_list, del_list);
+		}
+		item = __btrfs_next_delayed_item(item);
+	}
+	mutex_unlock(&node->mutex);
+
+	/*
+	 * We are called during inode logging, which means the inode is in use
+	 * and can not be evicted before we finish logging the inode. So we never
+	 * have the last reference on the delayed inode.
+	 * Also, we don't use btrfs_release_delayed_node() because that would
+	 * requeue the delayed inode (change its order in the list of prepared
+	 * nodes) and we don't want to do such change because we don't create or
+	 * delete delayed items.
+	 */
+	ASSERT(refcount_read(&node->refs) > 1);
+	refcount_dec(&node->refs);
+}
+
+void btrfs_log_put_delayed_items(struct btrfs_inode *inode,
+				 struct list_head *ins_list,
+				 struct list_head *del_list)
+{
+	struct btrfs_delayed_node *node;
+	struct btrfs_delayed_item *item;
+	struct btrfs_delayed_item *next;
+
+	node = btrfs_get_delayed_node(inode);
+	if (!node)
+		return;
+
+	mutex_lock(&node->mutex);
+
+	list_for_each_entry_safe(item, next, ins_list, log_list) {
+		item->logged = true;
+		list_del_init(&item->log_list);
+		if (refcount_dec_and_test(&item->refs))
+			kfree(item);
+	}
+
+	list_for_each_entry_safe(item, next, del_list, log_list) {
+		item->logged = true;
+		list_del_init(&item->log_list);
+		if (refcount_dec_and_test(&item->refs))
+			kfree(item);
+	}
+
+	mutex_unlock(&node->mutex);
+
+	/*
+	 * We are called during inode logging, which means the inode is in use
+	 * and can not be evicted before we finish logging the inode. So we never
+	 * have the last reference on the delayed inode.
+	 * Also, we don't use btrfs_release_delayed_node() because that would
+	 * requeue the delayed inode (change its order in the list of prepared
+	 * nodes) and we don't want to do such change because we don't create or
+	 * delete delayed items.
+	 */
+	ASSERT(refcount_read(&node->refs) > 1);
+	refcount_dec(&node->refs);
+}