diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index d2cf5a5..9adf5e4 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -8,7 +8,7 @@
 	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
 	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
 	   ref-cache.o export.o tree-log.o acl.o free-space-cache.o zlib.o \
-	   compression.o
+	   compression.o delayed-ref.o
 else
 
 # Normal Makefile
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 87c9038..bebc9fd 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -922,6 +922,7 @@
 		spin_unlock(&root->node_lock);
 
 		ret = btrfs_update_extent_ref(trans, root, child->start,
+					      child->len,
 					      mid->start, child->start,
 					      root->root_key.objectid,
 					      trans->transid, level - 1);
@@ -2075,7 +2076,7 @@
 	spin_unlock(&root->node_lock);
 
 	ret = btrfs_update_extent_ref(trans, root, lower->start,
-				      lower->start, c->start,
+				      lower->len, lower->start, c->start,
 				      root->root_key.objectid,
 				      trans->transid, level - 1);
 	BUG_ON(ret);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3a37ba7..ced5fd8 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -688,8 +688,6 @@
 	struct rb_root block_group_cache_tree;
 
 	struct extent_io_tree pinned_extents;
-	struct extent_io_tree pending_del;
-	struct extent_io_tree extent_ins;
 
 	/* logical->physical extent mapping */
 	struct btrfs_mapping_tree mapping_tree;
@@ -717,7 +715,6 @@
 	struct mutex tree_log_mutex;
 	struct mutex transaction_kthread_mutex;
 	struct mutex cleaner_mutex;
-	struct mutex extent_ins_mutex;
 	struct mutex pinned_mutex;
 	struct mutex chunk_mutex;
 	struct mutex drop_mutex;
@@ -1704,18 +1701,15 @@
 }
 
 /* extent-tree.c */
+int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
+			   struct btrfs_root *root, unsigned long count);
 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len);
-int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
-			    struct btrfs_root *root, u64 bytenr,
-			    u64 num_bytes, u32 *refs);
 int btrfs_update_pinned_extents(struct btrfs_root *root,
 				u64 bytenr, u64 num, int pin);
 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root, struct extent_buffer *leaf);
 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root, u64 objectid, u64 bytenr);
-int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
-			 struct btrfs_root *root);
 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy);
 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 						 struct btrfs_fs_info *info,
@@ -1777,7 +1771,7 @@
 			 u64 root_objectid, u64 ref_generation,
 			 u64 owner_objectid);
 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
-			    struct btrfs_root *root, u64 bytenr,
+			    struct btrfs_root *root, u64 bytenr, u64 num_bytes,
 			    u64 orig_parent, u64 parent,
 			    u64 root_objectid, u64 ref_generation,
 			    u64 owner_objectid);
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
new file mode 100644
index 0000000..874565a
--- /dev/null
+++ b/fs/btrfs/delayed-ref.c
@@ -0,0 +1,585 @@
+/*
+ * Copyright (C) 2009 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/sched.h>
+#include <linux/sort.h>
+#include <linux/ftrace.h>
+#include "ctree.h"
+#include "delayed-ref.h"
+#include "transaction.h"
+
+/*
+ * delayed back reference update tracking.  For subvolume trees
+ * we queue up extent allocations and backref maintenance for
+ * delayed processing.   This avoids deep call chains where we
+ * add extents in the middle of btrfs_search_slot, and it allows
+ * us to buffer up frequently modified backrefs in an rb tree instead
+ * of hammering updates on the extent allocation tree.
+ *
+ * Right now this code is only used for reference counted trees, but
+ * the long term goal is to get rid of the similar code for delayed
+ * extent tree modifications.
+ */
+
+/*
+ * entries in the rb tree are ordered by the byte number of the extent
+ * and by the byte number of the parent block.
+ */
+static int comp_entry(struct btrfs_delayed_ref_node *ref,
+		      u64 bytenr, u64 parent)
+{
+	if (bytenr < ref->bytenr)
+		return -1;
+	if (bytenr > ref->bytenr)
+		return 1;
+	if (parent < ref->parent)
+		return -1;
+	if (parent > ref->parent)
+		return 1;
+	return 0;
+}
+
+/*
+ * insert a new ref into the rbtree.  This returns any existing refs
+ * for the same (bytenr,parent) tuple, or NULL if the new node was properly
+ * inserted.
+ */
+static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
+						  u64 bytenr, u64 parent,
+						  struct rb_node *node)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent_node = NULL;
+	struct btrfs_delayed_ref_node *entry;
+	int cmp;
+
+	while (*p) {
+		parent_node = *p;
+		entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
+				 rb_node);
+
+		cmp = comp_entry(entry, bytenr, parent);
+		if (cmp < 0)
+			p = &(*p)->rb_left;
+		else if (cmp > 0)
+			p = &(*p)->rb_right;
+		else
+			return entry;
+	}
+
+	entry = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
+	rb_link_node(node, parent_node, p);
+	rb_insert_color(node, root);
+	return NULL;
+}
+
+/*
+ * find an entry based on (bytenr,parent).  This returns the delayed
+ * ref if it was able to find one, or NULL if nothing was in that spot
+ */
+static struct btrfs_delayed_ref_node *tree_search(struct rb_root *root,
+						  u64 bytenr, u64 parent)
+{
+	struct rb_node *n = root->rb_node;
+	struct btrfs_delayed_ref_node *entry;
+	int cmp;
+
+	while (n) {
+		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
+		WARN_ON(!entry->in_tree);
+
+		cmp = comp_entry(entry, bytenr, parent);
+		if (cmp < 0)
+			n = n->rb_left;
+		else if (cmp > 0)
+			n = n->rb_right;
+		else
+			return entry;
+	}
+	return NULL;
+}
+
+/*
+ * Locking on delayed refs is done by taking a lock on the head node,
+ * which has the (impossible) parent id of (u64)-1.  Once a lock is held
+ * on the head node, you're allowed (and required) to process all the
+ * delayed refs for a given byte number in the tree.
+ *
+ * This will walk forward in the rbtree until it finds a head node it
+ * is able to lock.  It might not lock the delayed ref you asked for,
+ * and so it will return the one it did lock in next_ret and return 0.
+ *
+ * If no locks are taken, next_ret is set to null and 1 is returned.  This
+ * means there are no more unlocked head nodes in the rbtree.
+ */
+int btrfs_lock_delayed_ref(struct btrfs_trans_handle *trans,
+			   struct btrfs_delayed_ref_node *ref,
+			   struct btrfs_delayed_ref_head **next_ret)
+{
+	struct rb_node *node;
+	struct btrfs_delayed_ref_head *head;
+	int ret = 0;
+
+	while (1) {
+		if (btrfs_delayed_ref_is_head(ref)) {
+			head = btrfs_delayed_node_to_head(ref);
+			if (mutex_trylock(&head->mutex)) {
+				*next_ret = head;
+				ret = 0;
+				break;
+			}
+		}
+		node = rb_next(&ref->rb_node);
+		if (!node) {
+			ret = 1;
+			*next_ret = NULL;
+			break;
+		}
+		ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
+	}
+	return ret;
+}
+
+/*
+ * This checks to see if there are any delayed refs in the
+ * btree for a given bytenr.  It returns one if it finds any
+ * and zero otherwise.
+ *
+ * If it only finds a head node, it returns 0.
+ *
+ * The idea is to use this when deciding if you can safely delete an
+ * extent from the extent allocation tree.  There may be a pending
+ * ref in the rbtree that adds or removes references, so as long as this
+ * returns one you need to leave the BTRFS_EXTENT_ITEM in the extent
+ * allocation tree.
+ */
+int btrfs_delayed_ref_pending(struct btrfs_trans_handle *trans, u64 bytenr)
+{
+	struct btrfs_delayed_ref_node *ref;
+	struct btrfs_delayed_ref_root *delayed_refs;
+	struct rb_node *prev_node;
+	int ret = 0;
+
+	delayed_refs = &trans->transaction->delayed_refs;
+	spin_lock(&delayed_refs->lock);
+
+	ref = tree_search(&delayed_refs->root, bytenr, (u64)-1);
+	if (ref) {
+		prev_node = rb_prev(&ref->rb_node);
+		if (!prev_node)
+			goto out;
+		ref = rb_entry(prev_node, struct btrfs_delayed_ref_node,
+			       rb_node);
+		if (ref->bytenr == bytenr)
+			ret = 1;
+	}
+out:
+	spin_unlock(&delayed_refs->lock);
+	return ret;
+}
+
+/*
+ * helper function to lookup reference count
+ *
+ * the head node for delayed ref is used to store the sum of all the
+ * reference count modifications queued up in the rbtree.  This way you
+ * can check to see what the reference count would be if all of the
+ * delayed refs are processed.
+ */
+int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
+			    struct btrfs_root *root, u64 bytenr,
+			    u64 num_bytes, u32 *refs)
+{
+	struct btrfs_delayed_ref_node *ref;
+	struct btrfs_delayed_ref_head *head;
+	struct btrfs_delayed_ref_root *delayed_refs;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_extent_item *ei;
+	struct btrfs_key key;
+	u32 num_refs;
+	int ret;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	key.objectid = bytenr;
+	key.type = BTRFS_EXTENT_ITEM_KEY;
+	key.offset = num_bytes;
+	delayed_refs = &trans->transaction->delayed_refs;
+again:
+	ret = btrfs_search_slot(trans, root->fs_info->extent_root,
+				&key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+
+	if (ret == 0) {
+		leaf = path->nodes[0];
+		ei = btrfs_item_ptr(leaf, path->slots[0],
+				    struct btrfs_extent_item);
+		num_refs = btrfs_extent_refs(leaf, ei);
+	} else {
+		num_refs = 0;
+		ret = 0;
+	}
+
+	spin_lock(&delayed_refs->lock);
+	ref = tree_search(&delayed_refs->root, bytenr, (u64)-1);
+	if (ref) {
+		head = btrfs_delayed_node_to_head(ref);
+		if (mutex_trylock(&head->mutex)) {
+			num_refs += ref->ref_mod;
+			mutex_unlock(&head->mutex);
+			*refs = num_refs;
+			goto out;
+		}
+
+		atomic_inc(&ref->refs);
+		spin_unlock(&delayed_refs->lock);
+
+		btrfs_release_path(root->fs_info->extent_root, path);
+
+		mutex_lock(&head->mutex);
+		mutex_unlock(&head->mutex);
+		btrfs_put_delayed_ref(ref);
+		goto again;
+	} else {
+		*refs = num_refs;
+	}
+out:
+	spin_unlock(&delayed_refs->lock);
+	btrfs_free_path(path);
+	return ret;
+}
+
+/*
+ * helper function to update an extent delayed ref in the
+ * rbtree.  existing and update must both have the same
+ * bytenr and parent
+ *
+ * This may free existing if the update cancels out whatever
+ * operation it was doing.
+ */
+static noinline void
+update_existing_ref(struct btrfs_trans_handle *trans,
+		    struct btrfs_delayed_ref_root *delayed_refs,
+		    struct btrfs_delayed_ref_node *existing,
+		    struct btrfs_delayed_ref_node *update)
+{
+	struct btrfs_delayed_ref *existing_ref;
+	struct btrfs_delayed_ref *ref;
+
+	existing_ref = btrfs_delayed_node_to_ref(existing);
+	ref = btrfs_delayed_node_to_ref(update);
+
+	if (ref->pin)
+		existing_ref->pin = 1;
+
+	if (ref->action != existing_ref->action) {
+		/*
+		 * this is effectively undoing either an add or a
+		 * drop.  We decrement the ref_mod, and if it goes
+		 * down to zero we just delete the entry without
+		 * every changing the extent allocation tree.
+		 */
+		existing->ref_mod--;
+		if (existing->ref_mod == 0) {
+			rb_erase(&existing->rb_node,
+				 &delayed_refs->root);
+			existing->in_tree = 0;
+			btrfs_put_delayed_ref(existing);
+			delayed_refs->num_entries--;
+			if (trans->delayed_ref_updates)
+				trans->delayed_ref_updates--;
+		}
+	} else {
+		if (existing_ref->action == BTRFS_ADD_DELAYED_REF) {
+			/* if we're adding refs, make sure all the
+			 * details match up.  The extent could
+			 * have been totally freed and reallocated
+			 * by a different owner before the delayed
+			 * ref entries were removed.
+			 */
+			existing_ref->owner_objectid = ref->owner_objectid;
+			existing_ref->generation = ref->generation;
+			existing_ref->root = ref->root;
+			existing->num_bytes = update->num_bytes;
+		}
+		/*
+		 * the action on the existing ref matches
+		 * the action on the ref we're trying to add.
+		 * Bump the ref_mod by one so the backref that
+		 * is eventually added/removed has the correct
+		 * reference count
+		 */
+		existing->ref_mod += update->ref_mod;
+	}
+}
+
+/*
+ * helper function to update the accounting in the head ref
+ * existing and update must have the same bytenr
+ */
+static noinline void
+update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
+			 struct btrfs_delayed_ref_node *update)
+{
+	struct btrfs_delayed_ref_head *existing_ref;
+	struct btrfs_delayed_ref_head *ref;
+
+	existing_ref = btrfs_delayed_node_to_head(existing);
+	ref = btrfs_delayed_node_to_head(update);
+
+	if (ref->must_insert_reserved) {
+		/* if the extent was freed and then
+		 * reallocated before the delayed ref
+		 * entries were processed, we can end up
+		 * with an existing head ref without
+		 * the must_insert_reserved flag set.
+		 * Set it again here
+		 */
+		existing_ref->must_insert_reserved = ref->must_insert_reserved;
+
+		/*
+		 * update the num_bytes so we make sure the accounting
+		 * is done correctly
+		 */
+		existing->num_bytes = update->num_bytes;
+
+	}
+
+	/*
+	 * update the reference mod on the head to reflect this new operation
+	 */
+	existing->ref_mod += update->ref_mod;
+}
+
+/*
+ * helper function to actually insert a delayed ref into the rbtree.
+ * this does all the dirty work in terms of maintaining the correct
+ * overall modification count in the head node and properly dealing
+ * with updating existing nodes as new modifications are queued.
+ */
+static noinline int __btrfs_add_delayed_ref(struct btrfs_trans_handle *trans,
+			  struct btrfs_delayed_ref_node *ref,
+			  u64 bytenr, u64 num_bytes, u64 parent, u64 ref_root,
+			  u64 ref_generation, u64 owner_objectid, int action,
+			  int pin)
+{
+	struct btrfs_delayed_ref_node *existing;
+	struct btrfs_delayed_ref *full_ref;
+	struct btrfs_delayed_ref_head *head_ref;
+	struct btrfs_delayed_ref_root *delayed_refs;
+	int count_mod = 1;
+	int must_insert_reserved = 0;
+
+	/*
+	 * the head node stores the sum of all the mods, so dropping a ref
+	 * should drop the sum in the head node by one.
+	 */
+	if (parent == (u64)-1 && action == BTRFS_DROP_DELAYED_REF)
+		count_mod = -1;
+
+	/*
+	 * BTRFS_ADD_DELAYED_EXTENT means that we need to update
+	 * the reserved accounting when the extent is finally added, or
+	 * if a later modification deletes the delayed ref without ever
+	 * inserting the extent into the extent allocation tree.
+	 * ref->must_insert_reserved is the flag used to record
+	 * that accounting mods are required.
+	 *
+	 * Once we record must_insert_reserved, switch the action to
+	 * BTRFS_ADD_DELAYED_REF because other special casing is not required.
+	 */
+	if (action == BTRFS_ADD_DELAYED_EXTENT) {
+		must_insert_reserved = 1;
+		action = BTRFS_ADD_DELAYED_REF;
+	} else {
+		must_insert_reserved = 0;
+	}
+
+
+	delayed_refs = &trans->transaction->delayed_refs;
+
+	/* first set the basic ref node struct up */
+	atomic_set(&ref->refs, 1);
+	ref->bytenr = bytenr;
+	ref->parent = parent;
+	ref->ref_mod = count_mod;
+	ref->in_tree = 1;
+	ref->num_bytes = num_bytes;
+
+	if (btrfs_delayed_ref_is_head(ref)) {
+		head_ref = btrfs_delayed_node_to_head(ref);
+		head_ref->must_insert_reserved = must_insert_reserved;
+		mutex_init(&head_ref->mutex);
+	} else {
+		full_ref = btrfs_delayed_node_to_ref(ref);
+		full_ref->root = ref_root;
+		full_ref->generation = ref_generation;
+		full_ref->owner_objectid = owner_objectid;
+		full_ref->pin = pin;
+		full_ref->action = action;
+	}
+
+	existing = tree_insert(&delayed_refs->root, bytenr,
+			       parent, &ref->rb_node);
+
+	if (existing) {
+		if (btrfs_delayed_ref_is_head(ref))
+			update_existing_head_ref(existing, ref);
+		else
+			update_existing_ref(trans, delayed_refs, existing, ref);
+
+		/*
+		 * we've updated the existing ref, free the newly
+		 * allocated ref
+		 */
+		kfree(ref);
+	} else {
+		delayed_refs->num_entries++;
+		trans->delayed_ref_updates++;
+	}
+	return 0;
+}
+
+/*
+ * add a delayed ref to the tree.  This does all of the accounting required
+ * to make sure the delayed ref is eventually processed before this
+ * transaction commits.
+ */
+int btrfs_add_delayed_ref(struct btrfs_trans_handle *trans,
+			  u64 bytenr, u64 num_bytes, u64 parent, u64 ref_root,
+			  u64 ref_generation, u64 owner_objectid, int action,
+			  int pin)
+{
+	struct btrfs_delayed_ref *ref;
+	struct btrfs_delayed_ref_head *head_ref;
+	struct btrfs_delayed_ref_root *delayed_refs;
+	int ret;
+
+	ref = kmalloc(sizeof(*ref), GFP_NOFS);
+	if (!ref)
+		return -ENOMEM;
+
+	/*
+	 * the parent = 0 case comes from cases where we don't actually
+	 * know the parent yet.  It will get updated later via a add/drop
+	 * pair.
+	 */
+	if (parent == 0)
+		parent = bytenr;
+
+	head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
+	if (!head_ref) {
+		kfree(ref);
+		return -ENOMEM;
+	}
+	delayed_refs = &trans->transaction->delayed_refs;
+	spin_lock(&delayed_refs->lock);
+
+	/*
+	 * insert both the head node and the new ref without dropping
+	 * the spin lock
+	 */
+	ret = __btrfs_add_delayed_ref(trans, &head_ref->node, bytenr, num_bytes,
+				      (u64)-1, 0, 0, 0, action, pin);
+	BUG_ON(ret);
+
+	ret = __btrfs_add_delayed_ref(trans, &ref->node, bytenr, num_bytes,
+				      parent, ref_root, ref_generation,
+				      owner_objectid, action, pin);
+	BUG_ON(ret);
+	spin_unlock(&delayed_refs->lock);
+	return 0;
+}
+
+/*
+ * add a delayed ref to the tree.  This does all of the accounting required
+ * to make sure the delayed ref is eventually processed before this
+ * transaction commits.
+ *
+ * The main point of this call is to add and remove a backreference in a single
+ * shot, taking the lock only once, and only searching for the head node once.
+ *
+ * It is the same as doing a ref add and delete in two separate calls.
+ */
+int btrfs_update_delayed_ref(struct btrfs_trans_handle *trans,
+			  u64 bytenr, u64 num_bytes, u64 orig_parent,
+			  u64 parent, u64 orig_ref_root, u64 ref_root,
+			  u64 orig_ref_generation, u64 ref_generation,
+			  u64 owner_objectid, int pin)
+{
+	struct btrfs_delayed_ref *ref;
+	struct btrfs_delayed_ref *old_ref;
+	struct btrfs_delayed_ref_head *head_ref;
+	struct btrfs_delayed_ref_root *delayed_refs;
+	int ret;
+
+	ref = kmalloc(sizeof(*ref), GFP_NOFS);
+	if (!ref)
+		return -ENOMEM;
+
+	old_ref = kmalloc(sizeof(*old_ref), GFP_NOFS);
+	if (!old_ref) {
+		kfree(ref);
+		return -ENOMEM;
+	}
+
+	/*
+	 * the parent = 0 case comes from cases where we don't actually
+	 * know the parent yet.  It will get updated later via a add/drop
+	 * pair.
+	 */
+	if (parent == 0)
+		parent = bytenr;
+	if (orig_parent == 0)
+		orig_parent = bytenr;
+
+	head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
+	if (!head_ref) {
+		kfree(ref);
+		kfree(old_ref);
+		return -ENOMEM;
+	}
+	delayed_refs = &trans->transaction->delayed_refs;
+	spin_lock(&delayed_refs->lock);
+
+	/*
+	 * insert both the head node and the new ref without dropping
+	 * the spin lock
+	 */
+	ret = __btrfs_add_delayed_ref(trans, &head_ref->node, bytenr, num_bytes,
+				      (u64)-1, 0, 0, 0,
+				      BTRFS_ADD_DELAYED_REF, 0);
+	BUG_ON(ret);
+
+	ret = __btrfs_add_delayed_ref(trans, &ref->node, bytenr, num_bytes,
+				      parent, ref_root, ref_generation,
+				      owner_objectid, BTRFS_ADD_DELAYED_REF, 0);
+	BUG_ON(ret);
+
+	ret = __btrfs_add_delayed_ref(trans, &old_ref->node, bytenr, num_bytes,
+				      orig_parent, orig_ref_root,
+				      orig_ref_generation, owner_objectid,
+				      BTRFS_DROP_DELAYED_REF, pin);
+	BUG_ON(ret);
+	spin_unlock(&delayed_refs->lock);
+	return 0;
+}
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
new file mode 100644
index 0000000..37919e5
--- /dev/null
+++ b/fs/btrfs/delayed-ref.h
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2008 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+#ifndef __DELAYED_REF__
+#define __DELAYED_REF__
+
+/* these are the possible values of struct btrfs_delayed_ref->action */
+#define BTRFS_ADD_DELAYED_REF    1 /* add one backref to the tree */
+#define BTRFS_DROP_DELAYED_REF   2 /* delete one backref from the tree */
+#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
+
+struct btrfs_delayed_ref_node {
+	struct rb_node rb_node;
+
+	/* the starting bytenr of the extent */
+	u64 bytenr;
+
+	/* the parent our backref will point to */
+	u64 parent;
+
+	/* the size of the extent */
+	u64 num_bytes;
+
+	/* ref count on this data structure */
+	atomic_t refs;
+
+	/*
+	 * how many refs is this entry adding or deleting.  For
+	 * head refs, this may be a negative number because it is keeping
+	 * track of the total mods done to the reference count.
+	 * For individual refs, this will always be a positive number
+	 *
+	 * It may be more than one, since it is possible for a single
+	 * parent to have more than one ref on an extent
+	 */
+	int ref_mod;
+
+	/* is this node still in the rbtree? */
+	unsigned int in_tree:1;
+};
+
+/*
+ * the head refs are used to hold a lock on a given extent, which allows us
+ * to make sure that only one process is running the delayed refs
+ * at a time for a single extent.  They also store the sum of all the
+ * reference count modifications we've queued up.
+ */
+struct btrfs_delayed_ref_head {
+	struct btrfs_delayed_ref_node node;
+
+	/*
+	 * the mutex is held while running the refs, and it is also
+	 * held when checking the sum of reference modifications.
+	 */
+	struct mutex mutex;
+
+	/*
+	 * when a new extent is allocated, it is just reserved in memory
+	 * The actual extent isn't inserted into the extent allocation tree
+	 * until the delayed ref is processed.  must_insert_reserved is
+	 * used to flag a delayed ref so the accounting can be updated
+	 * when a full insert is done.
+	 *
+	 * It is possible the extent will be freed before it is ever
+	 * inserted into the extent allocation tree.  In this case
+	 * we need to update the in ram accounting to properly reflect
+	 * the free has happened.
+	 */
+	unsigned int must_insert_reserved:1;
+};
+
+struct btrfs_delayed_ref {
+	struct btrfs_delayed_ref_node node;
+
+	/* the root objectid our ref will point to */
+	u64 root;
+
+	/* the generation for the backref */
+	u64 generation;
+
+	/* owner_objectid of the backref  */
+	u64 owner_objectid;
+
+	/* operation done by this entry in the rbtree */
+	u8 action;
+
+	/* if pin == 1, when the extent is freed it will be pinned until
+	 * transaction commit
+	 */
+	unsigned int pin:1;
+};
+
+struct btrfs_delayed_ref_root {
+	struct rb_root root;
+
+	/* this spin lock protects the rbtree and the entries inside */
+	spinlock_t lock;
+
+	/* how many delayed ref updates we've queued, used by the
+	 * throttling code
+	 */
+	unsigned long num_entries;
+
+	/*
+	 * set when the tree is flushing before a transaction commit,
+	 * used by the throttling code to decide if new updates need
+	 * to be run right away
+	 */
+	int flushing;
+};
+
+static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
+{
+	WARN_ON(atomic_read(&ref->refs) == 0);
+	if (atomic_dec_and_test(&ref->refs)) {
+		WARN_ON(ref->in_tree);
+		kfree(ref);
+	}
+}
+
+int btrfs_add_delayed_ref(struct btrfs_trans_handle *trans,
+			  u64 bytenr, u64 num_bytes, u64 parent, u64 ref_root,
+			  u64 ref_generation, u64 owner_objectid, int action,
+			  int pin);
+
+struct btrfs_delayed_ref *
+btrfs_find_delayed_ref(struct btrfs_trans_handle *trans, u64 bytenr,
+		       u64 parent);
+int btrfs_delayed_ref_pending(struct btrfs_trans_handle *trans, u64 bytenr);
+int btrfs_lock_delayed_ref(struct btrfs_trans_handle *trans,
+			   struct btrfs_delayed_ref_node *ref,
+			   struct btrfs_delayed_ref_head **next_ret);
+int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
+			    struct btrfs_root *root, u64 bytenr,
+			    u64 num_bytes, u32 *refs);
+int btrfs_update_delayed_ref(struct btrfs_trans_handle *trans,
+			  u64 bytenr, u64 num_bytes, u64 orig_parent,
+			  u64 parent, u64 orig_ref_root, u64 ref_root,
+			  u64 orig_ref_generation, u64 ref_generation,
+			  u64 owner_objectid, int pin);
+/*
+ * a node might live in a head or a regular ref, this lets you
+ * test for the proper type to use.
+ */
+static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
+{
+	return node->parent == (u64)-1;
+}
+
+/*
+ * helper functions to cast a node into its container
+ */
+static inline struct btrfs_delayed_ref *
+btrfs_delayed_node_to_ref(struct btrfs_delayed_ref_node *node)
+{
+	WARN_ON(btrfs_delayed_ref_is_head(node));
+	return container_of(node, struct btrfs_delayed_ref, node);
+
+}
+
+static inline struct btrfs_delayed_ref_head *
+btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
+{
+	WARN_ON(!btrfs_delayed_ref_is_head(node));
+	return container_of(node, struct btrfs_delayed_ref_head, node);
+
+}
+#endif
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3e18175..4f43e22 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1458,6 +1458,7 @@
 	struct btrfs_root *root = arg;
 	struct btrfs_trans_handle *trans;
 	struct btrfs_transaction *cur;
+	struct btrfs_fs_info *info = root->fs_info;
 	unsigned long now;
 	unsigned long delay;
 	int ret;
@@ -1471,12 +1472,6 @@
 		vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
 		mutex_lock(&root->fs_info->transaction_kthread_mutex);
 
-		if (root->fs_info->total_ref_cache_size > 20 * 1024 * 1024) {
-			printk(KERN_INFO "btrfs: total reference cache "
-			       "size %llu\n",
-			       root->fs_info->total_ref_cache_size);
-		}
-
 		mutex_lock(&root->fs_info->trans_mutex);
 		cur = root->fs_info->running_transaction;
 		if (!cur) {
@@ -1486,13 +1481,30 @@
 
 		now = get_seconds();
 		if (now < cur->start_time || now - cur->start_time < 30) {
+			unsigned long num_delayed;
+			num_delayed = cur->delayed_refs.num_entries;
 			mutex_unlock(&root->fs_info->trans_mutex);
 			delay = HZ * 5;
+
+			/*
+			 * we may have been woken up early to start
+			 * processing the delayed extent ref updates
+			 * If so, run some of them and then loop around again
+			 * to see if we need to force a commit
+			 */
+			if (num_delayed > 64) {
+				mutex_unlock(&info->transaction_kthread_mutex);
+				trans = btrfs_start_transaction(root, 1);
+				btrfs_run_delayed_refs(trans, root, 256);
+				btrfs_end_transaction(trans, root);
+				continue;
+			}
 			goto sleep;
 		}
 		mutex_unlock(&root->fs_info->trans_mutex);
 		trans = btrfs_start_transaction(root, 1);
 		ret = btrfs_commit_transaction(trans, root);
+
 sleep:
 		wake_up_process(root->fs_info->cleaner_kthread);
 		mutex_unlock(&root->fs_info->transaction_kthread_mutex);
@@ -1611,10 +1623,6 @@
 
 	extent_io_tree_init(&fs_info->pinned_extents,
 			     fs_info->btree_inode->i_mapping, GFP_NOFS);
-	extent_io_tree_init(&fs_info->pending_del,
-			     fs_info->btree_inode->i_mapping, GFP_NOFS);
-	extent_io_tree_init(&fs_info->extent_ins,
-			     fs_info->btree_inode->i_mapping, GFP_NOFS);
 	fs_info->do_barriers = 1;
 
 	INIT_LIST_HEAD(&fs_info->dead_reloc_roots);
@@ -1629,7 +1637,6 @@
 	mutex_init(&fs_info->trans_mutex);
 	mutex_init(&fs_info->tree_log_mutex);
 	mutex_init(&fs_info->drop_mutex);
-	mutex_init(&fs_info->extent_ins_mutex);
 	mutex_init(&fs_info->pinned_mutex);
 	mutex_init(&fs_info->chunk_mutex);
 	mutex_init(&fs_info->transaction_kthread_mutex);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fefe83a..9b5da2b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -49,10 +49,13 @@
 	int del;
 };
 
-static int finish_current_insert(struct btrfs_trans_handle *trans,
-				 struct btrfs_root *extent_root, int all);
-static int del_pending_extents(struct btrfs_trans_handle *trans,
-			       struct btrfs_root *extent_root, int all);
+static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
+					 struct btrfs_root *root, u64 parent,
+					 u64 root_objectid, u64 ref_generation,
+					 u64 owner, struct btrfs_key *ins,
+					 int ref_mod);
+static int update_reserved_extents(struct btrfs_root *root,
+				   u64 bytenr, u64 num, int reserve);
 static int pin_down_bytes(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  u64 bytenr, u64 num_bytes, int is_data);
@@ -60,6 +63,12 @@
 			      struct btrfs_root *root,
 			      u64 bytenr, u64 num_bytes, int alloc,
 			      int mark_free);
+static noinline int __btrfs_free_extent(struct btrfs_trans_handle *trans,
+					struct btrfs_root *root,
+					u64 bytenr, u64 num_bytes, u64 parent,
+					u64 root_objectid, u64 ref_generation,
+					u64 owner_objectid, int pin,
+					int ref_to_drop);
 
 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *extent_root, u64 alloc_bytes,
@@ -554,262 +563,13 @@
 	return ret;
 }
 
-/*
- * updates all the backrefs that are pending on update_list for the
- * extent_root
- */
-static noinline int update_backrefs(struct btrfs_trans_handle *trans,
-				    struct btrfs_root *extent_root,
-				    struct btrfs_path *path,
-				    struct list_head *update_list)
-{
-	struct btrfs_key key;
-	struct btrfs_extent_ref *ref;
-	struct btrfs_fs_info *info = extent_root->fs_info;
-	struct pending_extent_op *op;
-	struct extent_buffer *leaf;
-	int ret = 0;
-	struct list_head *cur = update_list->next;
-	u64 ref_objectid;
-	u64 ref_root = extent_root->root_key.objectid;
-
-	op = list_entry(cur, struct pending_extent_op, list);
-
-search:
-	key.objectid = op->bytenr;
-	key.type = BTRFS_EXTENT_REF_KEY;
-	key.offset = op->orig_parent;
-
-	ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 1);
-	BUG_ON(ret);
-
-	leaf = path->nodes[0];
-
-loop:
-	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
-
-	ref_objectid = btrfs_ref_objectid(leaf, ref);
-
-	if (btrfs_ref_root(leaf, ref) != ref_root ||
-	    btrfs_ref_generation(leaf, ref) != op->orig_generation ||
-	    (ref_objectid != op->level &&
-	     ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
-		printk(KERN_ERR "btrfs couldn't find %llu, parent %llu, "
-		       "root %llu, owner %u\n",
-		       (unsigned long long)op->bytenr,
-		       (unsigned long long)op->orig_parent,
-		       (unsigned long long)ref_root, op->level);
-		btrfs_print_leaf(extent_root, leaf);
-		BUG();
-	}
-
-	key.objectid = op->bytenr;
-	key.offset = op->parent;
-	key.type = BTRFS_EXTENT_REF_KEY;
-	ret = btrfs_set_item_key_safe(trans, extent_root, path, &key);
-	BUG_ON(ret);
-	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
-	btrfs_set_ref_generation(leaf, ref, op->generation);
-
-	cur = cur->next;
-
-	list_del_init(&op->list);
-	unlock_extent(&info->extent_ins, op->bytenr,
-		      op->bytenr + op->num_bytes - 1, GFP_NOFS);
-	kfree(op);
-
-	if (cur == update_list) {
-		btrfs_mark_buffer_dirty(path->nodes[0]);
-		btrfs_release_path(extent_root, path);
-		goto out;
-	}
-
-	op = list_entry(cur, struct pending_extent_op, list);
-
-	path->slots[0]++;
-	while (path->slots[0] < btrfs_header_nritems(leaf)) {
-		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
-		if (key.objectid == op->bytenr &&
-		    key.type == BTRFS_EXTENT_REF_KEY)
-			goto loop;
-		path->slots[0]++;
-	}
-
-	btrfs_mark_buffer_dirty(path->nodes[0]);
-	btrfs_release_path(extent_root, path);
-	goto search;
-
-out:
-	return 0;
-}
-
-static noinline int insert_extents(struct btrfs_trans_handle *trans,
-				   struct btrfs_root *extent_root,
-				   struct btrfs_path *path,
-				   struct list_head *insert_list, int nr)
-{
-	struct btrfs_key *keys;
-	u32 *data_size;
-	struct pending_extent_op *op;
-	struct extent_buffer *leaf;
-	struct list_head *cur = insert_list->next;
-	struct btrfs_fs_info *info = extent_root->fs_info;
-	u64 ref_root = extent_root->root_key.objectid;
-	int i = 0, last = 0, ret;
-	int total = nr * 2;
-
-	if (!nr)
-		return 0;
-
-	keys = kzalloc(total * sizeof(struct btrfs_key), GFP_NOFS);
-	if (!keys)
-		return -ENOMEM;
-
-	data_size = kzalloc(total * sizeof(u32), GFP_NOFS);
-	if (!data_size) {
-		kfree(keys);
-		return -ENOMEM;
-	}
-
-	list_for_each_entry(op, insert_list, list) {
-		keys[i].objectid = op->bytenr;
-		keys[i].offset = op->num_bytes;
-		keys[i].type = BTRFS_EXTENT_ITEM_KEY;
-		data_size[i] = sizeof(struct btrfs_extent_item);
-		i++;
-
-		keys[i].objectid = op->bytenr;
-		keys[i].offset = op->parent;
-		keys[i].type = BTRFS_EXTENT_REF_KEY;
-		data_size[i] = sizeof(struct btrfs_extent_ref);
-		i++;
-	}
-
-	op = list_entry(cur, struct pending_extent_op, list);
-	i = 0;
-	while (i < total) {
-		int c;
-		ret = btrfs_insert_some_items(trans, extent_root, path,
-					      keys+i, data_size+i, total-i);
-		BUG_ON(ret < 0);
-
-		if (last && ret > 1)
-			BUG();
-
-		leaf = path->nodes[0];
-		for (c = 0; c < ret; c++) {
-			int ref_first = keys[i].type == BTRFS_EXTENT_REF_KEY;
-
-			/*
-			 * if the first item we inserted was a backref, then
-			 * the EXTENT_ITEM will be the odd c's, else it will
-			 * be the even c's
-			 */
-			if ((ref_first && (c % 2)) ||
-			    (!ref_first && !(c % 2))) {
-				struct btrfs_extent_item *itm;
-
-				itm = btrfs_item_ptr(leaf, path->slots[0] + c,
-						     struct btrfs_extent_item);
-				btrfs_set_extent_refs(path->nodes[0], itm, 1);
-				op->del++;
-			} else {
-				struct btrfs_extent_ref *ref;
-
-				ref = btrfs_item_ptr(leaf, path->slots[0] + c,
-						     struct btrfs_extent_ref);
-				btrfs_set_ref_root(leaf, ref, ref_root);
-				btrfs_set_ref_generation(leaf, ref,
-							 op->generation);
-				btrfs_set_ref_objectid(leaf, ref, op->level);
-				btrfs_set_ref_num_refs(leaf, ref, 1);
-				op->del++;
-			}
-
-			/*
-			 * using del to see when its ok to free up the
-			 * pending_extent_op.  In the case where we insert the
-			 * last item on the list in order to help do batching
-			 * we need to not free the extent op until we actually
-			 * insert the extent_item
-			 */
-			if (op->del == 2) {
-				unlock_extent(&info->extent_ins, op->bytenr,
-					      op->bytenr + op->num_bytes - 1,
-					      GFP_NOFS);
-				cur = cur->next;
-				list_del_init(&op->list);
-				kfree(op);
-				if (cur != insert_list)
-					op = list_entry(cur,
-						struct pending_extent_op,
-						list);
-			}
-		}
-		btrfs_mark_buffer_dirty(leaf);
-		btrfs_release_path(extent_root, path);
-
-		/*
-		 * Ok backref's and items usually go right next to eachother,
-		 * but if we could only insert 1 item that means that we
-		 * inserted on the end of a leaf, and we have no idea what may
-		 * be on the next leaf so we just play it safe.  In order to
-		 * try and help this case we insert the last thing on our
-		 * insert list so hopefully it will end up being the last
-		 * thing on the leaf and everything else will be before it,
-		 * which will let us insert a whole bunch of items at the same
-		 * time.
-		 */
-		if (ret == 1 && !last && (i + ret < total)) {
-			/*
-			 * last: where we will pick up the next time around
-			 * i: our current key to insert, will be total - 1
-			 * cur: the current op we are screwing with
-			 * op: duh
-			 */
-			last = i + ret;
-			i = total - 1;
-			cur = insert_list->prev;
-			op = list_entry(cur, struct pending_extent_op, list);
-		} else if (last) {
-			/*
-			 * ok we successfully inserted the last item on the
-			 * list, lets reset everything
-			 *
-			 * i: our current key to insert, so where we left off
-			 *    last time
-			 * last: done with this
-			 * cur: the op we are messing with
-			 * op: duh
-			 * total: since we inserted the last key, we need to
-			 *        decrement total so we dont overflow
-			 */
-			i = last;
-			last = 0;
-			total--;
-			if (i < total) {
-				cur = insert_list->next;
-				op = list_entry(cur, struct pending_extent_op,
-						list);
-			}
-		} else {
-			i += ret;
-		}
-
-		cond_resched();
-	}
-	ret = 0;
-	kfree(keys);
-	kfree(data_size);
-	return ret;
-}
-
 static noinline int insert_extent_backref(struct btrfs_trans_handle *trans,
 					  struct btrfs_root *root,
 					  struct btrfs_path *path,
 					  u64 bytenr, u64 parent,
 					  u64 ref_root, u64 ref_generation,
-					  u64 owner_objectid)
+					  u64 owner_objectid,
+					  int refs_to_add)
 {
 	struct btrfs_key key;
 	struct extent_buffer *leaf;
@@ -829,9 +589,10 @@
 		btrfs_set_ref_root(leaf, ref, ref_root);
 		btrfs_set_ref_generation(leaf, ref, ref_generation);
 		btrfs_set_ref_objectid(leaf, ref, owner_objectid);
-		btrfs_set_ref_num_refs(leaf, ref, 1);
+		btrfs_set_ref_num_refs(leaf, ref, refs_to_add);
 	} else if (ret == -EEXIST) {
 		u64 existing_owner;
+
 		BUG_ON(owner_objectid < BTRFS_FIRST_FREE_OBJECTID);
 		leaf = path->nodes[0];
 		ref = btrfs_item_ptr(leaf, path->slots[0],
@@ -845,7 +606,7 @@
 
 		num_refs = btrfs_ref_num_refs(leaf, ref);
 		BUG_ON(num_refs == 0);
-		btrfs_set_ref_num_refs(leaf, ref, num_refs + 1);
+		btrfs_set_ref_num_refs(leaf, ref, num_refs + refs_to_add);
 
 		existing_owner = btrfs_ref_objectid(leaf, ref);
 		if (existing_owner != owner_objectid &&
@@ -865,7 +626,8 @@
 
 static noinline int remove_extent_backref(struct btrfs_trans_handle *trans,
 					  struct btrfs_root *root,
-					  struct btrfs_path *path)
+					  struct btrfs_path *path,
+					  int refs_to_drop)
 {
 	struct extent_buffer *leaf;
 	struct btrfs_extent_ref *ref;
@@ -875,8 +637,8 @@
 	leaf = path->nodes[0];
 	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 	num_refs = btrfs_ref_num_refs(leaf, ref);
-	BUG_ON(num_refs == 0);
-	num_refs -= 1;
+	BUG_ON(num_refs < refs_to_drop);
+	num_refs -= refs_to_drop;
 	if (num_refs == 0) {
 		ret = btrfs_del_item(trans, root, path);
 	} else {
@@ -927,332 +689,28 @@
 #endif
 }
 
-static noinline int free_extents(struct btrfs_trans_handle *trans,
-				 struct btrfs_root *extent_root,
-				 struct list_head *del_list)
-{
-	struct btrfs_fs_info *info = extent_root->fs_info;
-	struct btrfs_path *path;
-	struct btrfs_key key, found_key;
-	struct extent_buffer *leaf;
-	struct list_head *cur;
-	struct pending_extent_op *op;
-	struct btrfs_extent_item *ei;
-	int ret, num_to_del, extent_slot = 0, found_extent = 0;
-	u32 refs;
-	u64 bytes_freed = 0;
-
-	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
-	path->reada = 1;
-
-search:
-	/* search for the backref for the current ref we want to delete */
-	cur = del_list->next;
-	op = list_entry(cur, struct pending_extent_op, list);
-	ret = lookup_extent_backref(trans, extent_root, path, op->bytenr,
-				    op->orig_parent,
-				    extent_root->root_key.objectid,
-				    op->orig_generation, op->level, 1);
-	if (ret) {
-		printk(KERN_ERR "btrfs unable to find backref byte nr %llu "
-		       "root %llu gen %llu owner %u\n",
-		       (unsigned long long)op->bytenr,
-		       (unsigned long long)extent_root->root_key.objectid,
-		       (unsigned long long)op->orig_generation, op->level);
-		btrfs_print_leaf(extent_root, path->nodes[0]);
-		WARN_ON(1);
-		goto out;
-	}
-
-	extent_slot = path->slots[0];
-	num_to_del = 1;
-	found_extent = 0;
-
-	/*
-	 * if we aren't the first item on the leaf we can move back one and see
-	 * if our ref is right next to our extent item
-	 */
-	if (likely(extent_slot)) {
-		extent_slot--;
-		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
-				      extent_slot);
-		if (found_key.objectid == op->bytenr &&
-		    found_key.type == BTRFS_EXTENT_ITEM_KEY &&
-		    found_key.offset == op->num_bytes) {
-			num_to_del++;
-			found_extent = 1;
-		}
-	}
-
-	/*
-	 * if we didn't find the extent we need to delete the backref and then
-	 * search for the extent item key so we can update its ref count
-	 */
-	if (!found_extent) {
-		key.objectid = op->bytenr;
-		key.type = BTRFS_EXTENT_ITEM_KEY;
-		key.offset = op->num_bytes;
-
-		ret = remove_extent_backref(trans, extent_root, path);
-		BUG_ON(ret);
-		btrfs_release_path(extent_root, path);
-		ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
-		BUG_ON(ret);
-		extent_slot = path->slots[0];
-	}
-
-	/* this is where we update the ref count for the extent */
-	leaf = path->nodes[0];
-	ei = btrfs_item_ptr(leaf, extent_slot, struct btrfs_extent_item);
-	refs = btrfs_extent_refs(leaf, ei);
-	BUG_ON(refs == 0);
-	refs--;
-	btrfs_set_extent_refs(leaf, ei, refs);
-
-	btrfs_mark_buffer_dirty(leaf);
-
-	/*
-	 * This extent needs deleting.  The reason cur_slot is extent_slot +
-	 * num_to_del is because extent_slot points to the slot where the extent
-	 * is, and if the backref was not right next to the extent we will be
-	 * deleting at least 1 item, and will want to start searching at the
-	 * slot directly next to extent_slot.  However if we did find the
-	 * backref next to the extent item them we will be deleting at least 2
-	 * items and will want to start searching directly after the ref slot
-	 */
-	if (!refs) {
-		struct list_head *pos, *n, *end;
-		int cur_slot = extent_slot+num_to_del;
-		u64 super_used;
-		u64 root_used;
-
-		path->slots[0] = extent_slot;
-		bytes_freed = op->num_bytes;
-
-		mutex_lock(&info->pinned_mutex);
-		ret = pin_down_bytes(trans, extent_root, op->bytenr,
-				     op->num_bytes, op->level >=
-				     BTRFS_FIRST_FREE_OBJECTID);
-		mutex_unlock(&info->pinned_mutex);
-		BUG_ON(ret < 0);
-		op->del = ret;
-
-		/*
-		 * we need to see if we can delete multiple things at once, so
-		 * start looping through the list of extents we are wanting to
-		 * delete and see if their extent/backref's are right next to
-		 * eachother and the extents only have 1 ref
-		 */
-		for (pos = cur->next; pos != del_list; pos = pos->next) {
-			struct pending_extent_op *tmp;
-
-			tmp = list_entry(pos, struct pending_extent_op, list);
-
-			/* we only want to delete extent+ref at this stage */
-			if (cur_slot >= btrfs_header_nritems(leaf) - 1)
-				break;
-
-			btrfs_item_key_to_cpu(leaf, &found_key, cur_slot);
-			if (found_key.objectid != tmp->bytenr ||
-			    found_key.type != BTRFS_EXTENT_ITEM_KEY ||
-			    found_key.offset != tmp->num_bytes)
-				break;
-
-			/* check to make sure this extent only has one ref */
-			ei = btrfs_item_ptr(leaf, cur_slot,
-					    struct btrfs_extent_item);
-			if (btrfs_extent_refs(leaf, ei) != 1)
-				break;
-
-			btrfs_item_key_to_cpu(leaf, &found_key, cur_slot+1);
-			if (found_key.objectid != tmp->bytenr ||
-			    found_key.type != BTRFS_EXTENT_REF_KEY ||
-			    found_key.offset != tmp->orig_parent)
-				break;
-
-			/*
-			 * the ref is right next to the extent, we can set the
-			 * ref count to 0 since we will delete them both now
-			 */
-			btrfs_set_extent_refs(leaf, ei, 0);
-
-			/* pin down the bytes for this extent */
-			mutex_lock(&info->pinned_mutex);
-			ret = pin_down_bytes(trans, extent_root, tmp->bytenr,
-					     tmp->num_bytes, tmp->level >=
-					     BTRFS_FIRST_FREE_OBJECTID);
-			mutex_unlock(&info->pinned_mutex);
-			BUG_ON(ret < 0);
-
-			/*
-			 * use the del field to tell if we need to go ahead and
-			 * free up the extent when we delete the item or not.
-			 */
-			tmp->del = ret;
-			bytes_freed += tmp->num_bytes;
-
-			num_to_del += 2;
-			cur_slot += 2;
-		}
-		end = pos;
-
-		/* update the free space counters */
-		spin_lock(&info->delalloc_lock);
-		super_used = btrfs_super_bytes_used(&info->super_copy);
-		btrfs_set_super_bytes_used(&info->super_copy,
-					   super_used - bytes_freed);
-
-		root_used = btrfs_root_used(&extent_root->root_item);
-		btrfs_set_root_used(&extent_root->root_item,
-				    root_used - bytes_freed);
-		spin_unlock(&info->delalloc_lock);
-
-		/* delete the items */
-		ret = btrfs_del_items(trans, extent_root, path,
-				      path->slots[0], num_to_del);
-		BUG_ON(ret);
-
-		/*
-		 * loop through the extents we deleted and do the cleanup work
-		 * on them
-		 */
-		for (pos = cur, n = pos->next; pos != end;
-		     pos = n, n = pos->next) {
-			struct pending_extent_op *tmp;
-			tmp = list_entry(pos, struct pending_extent_op, list);
-
-			/*
-			 * remember tmp->del tells us wether or not we pinned
-			 * down the extent
-			 */
-			ret = update_block_group(trans, extent_root,
-						 tmp->bytenr, tmp->num_bytes, 0,
-						 tmp->del);
-			BUG_ON(ret);
-
-			list_del_init(&tmp->list);
-			unlock_extent(&info->extent_ins, tmp->bytenr,
-				      tmp->bytenr + tmp->num_bytes - 1,
-				      GFP_NOFS);
-			kfree(tmp);
-		}
-	} else if (refs && found_extent) {
-		/*
-		 * the ref and extent were right next to eachother, but the
-		 * extent still has a ref, so just free the backref and keep
-		 * going
-		 */
-		ret = remove_extent_backref(trans, extent_root, path);
-		BUG_ON(ret);
-
-		list_del_init(&op->list);
-		unlock_extent(&info->extent_ins, op->bytenr,
-			      op->bytenr + op->num_bytes - 1, GFP_NOFS);
-		kfree(op);
-	} else {
-		/*
-		 * the extent has multiple refs and the backref we were looking
-		 * for was not right next to it, so just unlock and go next,
-		 * we're good to go
-		 */
-		list_del_init(&op->list);
-		unlock_extent(&info->extent_ins, op->bytenr,
-			      op->bytenr + op->num_bytes - 1, GFP_NOFS);
-		kfree(op);
-	}
-
-	btrfs_release_path(extent_root, path);
-	if (!list_empty(del_list))
-		goto search;
-
-out:
-	btrfs_free_path(path);
-	return ret;
-}
-
 static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root, u64 bytenr,
+				     u64 num_bytes,
 				     u64 orig_parent, u64 parent,
 				     u64 orig_root, u64 ref_root,
 				     u64 orig_generation, u64 ref_generation,
 				     u64 owner_objectid)
 {
 	int ret;
-	struct btrfs_root *extent_root = root->fs_info->extent_root;
-	struct btrfs_path *path;
+	int pin = owner_objectid < BTRFS_FIRST_FREE_OBJECTID;
 
-	if (root == root->fs_info->extent_root) {
-		struct pending_extent_op *extent_op;
-		u64 num_bytes;
-
-		BUG_ON(owner_objectid >= BTRFS_MAX_LEVEL);
-		num_bytes = btrfs_level_size(root, (int)owner_objectid);
-		mutex_lock(&root->fs_info->extent_ins_mutex);
-		if (test_range_bit(&root->fs_info->extent_ins, bytenr,
-				bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
-			u64 priv;
-			ret = get_state_private(&root->fs_info->extent_ins,
-						bytenr, &priv);
-			BUG_ON(ret);
-			extent_op = (struct pending_extent_op *)
-							(unsigned long)priv;
-			BUG_ON(extent_op->parent != orig_parent);
-			BUG_ON(extent_op->generation != orig_generation);
-
-			extent_op->parent = parent;
-			extent_op->generation = ref_generation;
-		} else {
-			extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
-			BUG_ON(!extent_op);
-
-			extent_op->type = PENDING_BACKREF_UPDATE;
-			extent_op->bytenr = bytenr;
-			extent_op->num_bytes = num_bytes;
-			extent_op->parent = parent;
-			extent_op->orig_parent = orig_parent;
-			extent_op->generation = ref_generation;
-			extent_op->orig_generation = orig_generation;
-			extent_op->level = (int)owner_objectid;
-			INIT_LIST_HEAD(&extent_op->list);
-			extent_op->del = 0;
-
-			set_extent_bits(&root->fs_info->extent_ins,
-					bytenr, bytenr + num_bytes - 1,
-					EXTENT_WRITEBACK, GFP_NOFS);
-			set_state_private(&root->fs_info->extent_ins,
-					  bytenr, (unsigned long)extent_op);
-		}
-		mutex_unlock(&root->fs_info->extent_ins_mutex);
-		return 0;
-	}
-
-	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
-	ret = lookup_extent_backref(trans, extent_root, path,
-				    bytenr, orig_parent, orig_root,
-				    orig_generation, owner_objectid, 1);
-	if (ret)
-		goto out;
-	ret = remove_extent_backref(trans, extent_root, path);
-	if (ret)
-		goto out;
-	ret = insert_extent_backref(trans, extent_root, path, bytenr,
-				    parent, ref_root, ref_generation,
-				    owner_objectid);
+	ret = btrfs_update_delayed_ref(trans, bytenr, num_bytes,
+				       orig_parent, parent, orig_root,
+				       ref_root, orig_generation,
+				       ref_generation, owner_objectid, pin);
 	BUG_ON(ret);
-	finish_current_insert(trans, extent_root, 0);
-	del_pending_extents(trans, extent_root, 0);
-out:
-	btrfs_free_path(path);
 	return ret;
 }
 
 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root, u64 bytenr,
-			    u64 orig_parent, u64 parent,
+			    u64 num_bytes, u64 orig_parent, u64 parent,
 			    u64 ref_root, u64 ref_generation,
 			    u64 owner_objectid)
 {
@@ -1260,20 +718,36 @@
 	if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 	    owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 		return 0;
-	ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
-					parent, ref_root, ref_root,
-					ref_generation, ref_generation,
-					owner_objectid);
+
+	ret = __btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
+					orig_parent, parent, ref_root,
+					ref_root, ref_generation,
+					ref_generation, owner_objectid);
 	return ret;
 }
-
 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 				  struct btrfs_root *root, u64 bytenr,
+				  u64 num_bytes,
 				  u64 orig_parent, u64 parent,
 				  u64 orig_root, u64 ref_root,
 				  u64 orig_generation, u64 ref_generation,
 				  u64 owner_objectid)
 {
+	int ret;
+
+	ret = btrfs_add_delayed_ref(trans, bytenr, num_bytes, parent, ref_root,
+				    ref_generation, owner_objectid,
+				    BTRFS_ADD_DELAYED_REF, 0);
+	BUG_ON(ret);
+	return ret;
+}
+
+static noinline_for_stack int add_extent_ref(struct btrfs_trans_handle *trans,
+			  struct btrfs_root *root, u64 bytenr,
+			  u64 num_bytes, u64 parent, u64 ref_root,
+			  u64 ref_generation, u64 owner_objectid,
+			  int refs_to_add)
+{
 	struct btrfs_path *path;
 	int ret;
 	struct btrfs_key key;
@@ -1288,15 +762,19 @@
 	path->reada = 1;
 	key.objectid = bytenr;
 	key.type = BTRFS_EXTENT_ITEM_KEY;
-	key.offset = (u64)-1;
+	key.offset = num_bytes;
 
-	ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
-				0, 1);
+	/* first find the extent item and update its reference count */
+	ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
+				path, 0, 1);
 	if (ret < 0)
 		return ret;
-	BUG_ON(ret == 0 || path->slots[0] == 0);
 
-	path->slots[0]--;
+	if (ret > 0) {
+		WARN_ON(1);
+		btrfs_free_path(path);
+		return -EIO;
+	}
 	l = path->nodes[0];
 
 	btrfs_item_key_to_cpu(l, &key, path->slots[0]);
@@ -1310,21 +788,20 @@
 	BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
 
 	item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
+
 	refs = btrfs_extent_refs(l, item);
-	btrfs_set_extent_refs(l, item, refs + 1);
+	btrfs_set_extent_refs(l, item, refs + refs_to_add);
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 
 	btrfs_release_path(root->fs_info->extent_root, path);
 
 	path->reada = 1;
+	/* now insert the actual backref */
 	ret = insert_extent_backref(trans, root->fs_info->extent_root,
 				    path, bytenr, parent,
 				    ref_root, ref_generation,
-				    owner_objectid);
+				    owner_objectid, refs_to_add);
 	BUG_ON(ret);
-	finish_current_insert(trans, root->fs_info->extent_root, 0);
-	del_pending_extents(trans, root->fs_info->extent_root, 0);
-
 	btrfs_free_path(path);
 	return 0;
 }
@@ -1339,68 +816,245 @@
 	if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 	    owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 		return 0;
-	ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
+
+	ret = __btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0, parent,
 				     0, ref_root, 0, ref_generation,
 				     owner_objectid);
 	return ret;
 }
 
-int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
-			 struct btrfs_root *root)
+static int drop_delayed_ref(struct btrfs_trans_handle *trans,
+					struct btrfs_root *root,
+					struct btrfs_delayed_ref_node *node)
 {
-	u64 start;
-	u64 end;
+	int ret = 0;
+	struct btrfs_delayed_ref *ref = btrfs_delayed_node_to_ref(node);
+
+	BUG_ON(node->ref_mod == 0);
+	ret = __btrfs_free_extent(trans, root, node->bytenr, node->num_bytes,
+				  node->parent, ref->root, ref->generation,
+				  ref->owner_objectid, ref->pin, node->ref_mod);
+
+	return ret;
+}
+
+/* helper function to actually process a single delayed ref entry */
+static noinline int run_one_delayed_ref(struct btrfs_trans_handle *trans,
+					struct btrfs_root *root,
+					struct btrfs_delayed_ref_node *node,
+					int insert_reserved)
+{
 	int ret;
+	struct btrfs_delayed_ref *ref;
 
-	while(1) {
-		finish_current_insert(trans, root->fs_info->extent_root, 1);
-		del_pending_extents(trans, root->fs_info->extent_root, 1);
+	if (node->parent == (u64)-1) {
+		struct btrfs_delayed_ref_head *head;
+		/*
+		 * we've hit the end of the chain and we were supposed
+		 * to insert this extent into the tree.  But, it got
+		 * deleted before we ever needed to insert it, so all
+		 * we have to do is clean up the accounting
+		 */
+		if (insert_reserved) {
+			update_reserved_extents(root, node->bytenr,
+						node->num_bytes, 0);
+		}
+		head = btrfs_delayed_node_to_head(node);
+		mutex_unlock(&head->mutex);
+		return 0;
+	}
 
-		/* is there more work to do? */
-		ret = find_first_extent_bit(&root->fs_info->pending_del,
-					    0, &start, &end, EXTENT_WRITEBACK);
-		if (!ret)
-			continue;
-		ret = find_first_extent_bit(&root->fs_info->extent_ins,
-					    0, &start, &end, EXTENT_WRITEBACK);
-		if (!ret)
-			continue;
-		break;
+	ref = btrfs_delayed_node_to_ref(node);
+	if (ref->action == BTRFS_ADD_DELAYED_REF) {
+		if (insert_reserved) {
+			struct btrfs_key ins;
+
+			ins.objectid = node->bytenr;
+			ins.offset = node->num_bytes;
+			ins.type = BTRFS_EXTENT_ITEM_KEY;
+
+			/* record the full extent allocation */
+			ret = __btrfs_alloc_reserved_extent(trans, root,
+					node->parent, ref->root,
+					ref->generation, ref->owner_objectid,
+					&ins, node->ref_mod);
+			update_reserved_extents(root, node->bytenr,
+						node->num_bytes, 0);
+		} else {
+			/* just add one backref */
+			ret = add_extent_ref(trans, root, node->bytenr,
+				     node->num_bytes,
+				     node->parent, ref->root, ref->generation,
+				     ref->owner_objectid, node->ref_mod);
+		}
+		BUG_ON(ret);
+	} else if (ref->action == BTRFS_DROP_DELAYED_REF) {
+		WARN_ON(insert_reserved);
+		ret = drop_delayed_ref(trans, root, node);
 	}
 	return 0;
 }
 
-int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
-			    struct btrfs_root *root, u64 bytenr,
-			    u64 num_bytes, u32 *refs)
+static noinline struct btrfs_delayed_ref_node *
+select_delayed_ref(struct btrfs_delayed_ref_head *head)
 {
-	struct btrfs_path *path;
-	int ret;
-	struct btrfs_key key;
-	struct extent_buffer *l;
-	struct btrfs_extent_item *item;
-
-	WARN_ON(num_bytes < root->sectorsize);
-	path = btrfs_alloc_path();
-	path->reada = 1;
-	key.objectid = bytenr;
-	key.offset = num_bytes;
-	btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
-	ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
-				0, 0);
-	if (ret < 0)
-		goto out;
-	if (ret != 0) {
-		btrfs_print_leaf(root, path->nodes[0]);
-		printk(KERN_INFO "btrfs failed to find block number %llu\n",
-		       (unsigned long long)bytenr);
-		BUG();
+	struct rb_node *node;
+	struct btrfs_delayed_ref_node *ref;
+	int action = BTRFS_ADD_DELAYED_REF;
+again:
+	/*
+	 * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
+	 * this prevents ref count from going down to zero when
+	 * there still are pending delayed ref.
+	 */
+	node = rb_prev(&head->node.rb_node);
+	while (1) {
+		if (!node)
+			break;
+		ref = rb_entry(node, struct btrfs_delayed_ref_node,
+				rb_node);
+		if (ref->bytenr != head->node.bytenr)
+			break;
+		if (btrfs_delayed_node_to_ref(ref)->action == action)
+			return ref;
+		node = rb_prev(node);
 	}
-	l = path->nodes[0];
-	item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
-	*refs = btrfs_extent_refs(l, item);
+	if (action == BTRFS_ADD_DELAYED_REF) {
+		action = BTRFS_DROP_DELAYED_REF;
+		goto again;
+	}
+	return NULL;
+}
+
+/*
+ * this starts processing the delayed reference count updates and
+ * extent insertions we have queued up so far.  count can be
+ * 0, which means to process everything in the tree at the start
+ * of the run (but not newly added entries), or it can be some target
+ * number you'd like to process.
+ */
+int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
+			   struct btrfs_root *root, unsigned long count)
+{
+	struct rb_node *node;
+	struct btrfs_delayed_ref_root *delayed_refs;
+	struct btrfs_delayed_ref_node *ref;
+	struct btrfs_delayed_ref_head *locked_ref = NULL;
+	int ret;
+	int must_insert_reserved = 0;
+	int run_all = count == (unsigned long)-1;
+
+	if (root == root->fs_info->extent_root)
+		root = root->fs_info->tree_root;
+
+	delayed_refs = &trans->transaction->delayed_refs;
+again:
+	spin_lock(&delayed_refs->lock);
+	if (count == 0)
+		count = delayed_refs->num_entries;
+	while (1) {
+		if (!locked_ref) {
+			/*
+			 * no locked ref, go find something we can
+			 * process in the rbtree.  We start at
+			 * the beginning of the tree, there may be less
+			 * lock contention if we do something smarter here.
+			 */
+			node = rb_first(&delayed_refs->root);
+			if (!node) {
+				spin_unlock(&delayed_refs->lock);
+				break;
+			}
+
+			ref = rb_entry(node, struct btrfs_delayed_ref_node,
+				       rb_node);
+			ret = btrfs_lock_delayed_ref(trans, ref, &locked_ref);
+			if (ret) {
+				spin_unlock(&delayed_refs->lock);
+				break;
+			}
+		}
+
+		/*
+		 * record the must insert reserved flag before we
+		 * drop the spin lock.
+		 */
+		must_insert_reserved = locked_ref->must_insert_reserved;
+		locked_ref->must_insert_reserved = 0;
+
+		/*
+		 * locked_ref is the head node, so we have to go one
+		 * node back for any delayed ref updates
+		 */
+
+		ref = select_delayed_ref(locked_ref);
+		if (!ref) {
+			/* All delayed refs have been processed, Go ahead
+			 * and send the head node to run_one_delayed_ref,
+			 * so that any accounting fixes can happen
+			 */
+			ref = &locked_ref->node;
+			locked_ref = NULL;
+		}
+
+		ref->in_tree = 0;
+		rb_erase(&ref->rb_node, &delayed_refs->root);
+		delayed_refs->num_entries--;
+		spin_unlock(&delayed_refs->lock);
+
+		ret = run_one_delayed_ref(trans, root, ref,
+					  must_insert_reserved);
+		BUG_ON(ret);
+		btrfs_put_delayed_ref(ref);
+
+		/* once we lock the head ref, we have to process all the
+		 * entries for it.  So, we might end up doing more entries
+		 * that count was asking us to do.
+		 */
+		if (count > 0)
+			count--;
+
+		/*
+		 * we set locked_ref to null above if we're all done
+		 * with this bytenr
+		 */
+		if (!locked_ref && count == 0)
+			break;
+
+		spin_lock(&delayed_refs->lock);
+	}
+	if (run_all) {
+		spin_lock(&delayed_refs->lock);
+		node = rb_first(&delayed_refs->root);
+		if (!node) {
+			spin_unlock(&delayed_refs->lock);
+			goto out;
+		}
+
+		while (node) {
+			ref = rb_entry(node, struct btrfs_delayed_ref_node,
+				       rb_node);
+			if (btrfs_delayed_ref_is_head(ref)) {
+				struct btrfs_delayed_ref_head *head;
+
+				head = btrfs_delayed_node_to_head(ref);
+				atomic_inc(&ref->refs);
+
+				spin_unlock(&delayed_refs->lock);
+				mutex_lock(&head->mutex);
+				mutex_unlock(&head->mutex);
+
+				btrfs_put_delayed_ref(ref);
+				goto again;
+			}
+			node = rb_next(node);
+		}
+		spin_unlock(&delayed_refs->lock);
+		count = (unsigned long)-1;
+		schedule_timeout(1);
+		goto again;
+	}
 out:
-	btrfs_free_path(path);
 	return 0;
 }
 
@@ -1624,7 +1278,7 @@
 	int refi = 0;
 	int slot;
 	int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
-			    u64, u64, u64, u64, u64, u64, u64, u64);
+			    u64, u64, u64, u64, u64, u64, u64, u64, u64);
 
 	ref_root = btrfs_header_owner(buf);
 	ref_generation = btrfs_header_generation(buf);
@@ -1696,12 +1350,19 @@
 
 		if (level == 0) {
 			btrfs_item_key_to_cpu(buf, &key, slot);
+			fi = btrfs_item_ptr(buf, slot,
+					    struct btrfs_file_extent_item);
+
+			bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
+			if (bytenr == 0)
+				continue;
 
 			ret = process_func(trans, root, bytenr,
-					   orig_buf->start, buf->start,
-					   orig_root, ref_root,
-					   orig_generation, ref_generation,
-					   key.objectid);
+				   btrfs_file_extent_disk_num_bytes(buf, fi),
+				   orig_buf->start, buf->start,
+				   orig_root, ref_root,
+				   orig_generation, ref_generation,
+				   key.objectid);
 
 			if (ret) {
 				faili = slot;
@@ -1709,7 +1370,7 @@
 				goto fail;
 			}
 		} else {
-			ret = process_func(trans, root, bytenr,
+			ret = process_func(trans, root, bytenr, buf->len,
 					   orig_buf->start, buf->start,
 					   orig_root, ref_root,
 					   orig_generation, ref_generation,
@@ -1786,17 +1447,17 @@
 			if (bytenr == 0)
 				continue;
 			ret = __btrfs_update_extent_ref(trans, root, bytenr,
-					    orig_buf->start, buf->start,
-					    orig_root, ref_root,
-					    orig_generation, ref_generation,
-					    key.objectid);
+				    btrfs_file_extent_disk_num_bytes(buf, fi),
+				    orig_buf->start, buf->start,
+				    orig_root, ref_root, orig_generation,
+				    ref_generation, key.objectid);
 			if (ret)
 				goto fail;
 		} else {
 			bytenr = btrfs_node_blockptr(buf, slot);
 			ret = __btrfs_update_extent_ref(trans, root, bytenr,
-					    orig_buf->start, buf->start,
-					    orig_root, ref_root,
+					    buf->len, orig_buf->start,
+					    buf->start, orig_root, ref_root,
 					    orig_generation, ref_generation,
 					    level - 1);
 			if (ret)
@@ -1815,7 +1476,6 @@
 				 struct btrfs_block_group_cache *cache)
 {
 	int ret;
-	int pending_ret;
 	struct btrfs_root *extent_root = root->fs_info->extent_root;
 	unsigned long bi;
 	struct extent_buffer *leaf;
@@ -1831,12 +1491,8 @@
 	btrfs_mark_buffer_dirty(leaf);
 	btrfs_release_path(extent_root, path);
 fail:
-	finish_current_insert(trans, extent_root, 0);
-	pending_ret = del_pending_extents(trans, extent_root, 0);
 	if (ret)
 		return ret;
-	if (pending_ret)
-		return pending_ret;
 	return 0;
 
 }
@@ -2474,193 +2130,6 @@
 	return ret;
 }
 
-static int finish_current_insert(struct btrfs_trans_handle *trans,
-				 struct btrfs_root *extent_root, int all)
-{
-	u64 start;
-	u64 end;
-	u64 priv;
-	u64 search = 0;
-	struct btrfs_fs_info *info = extent_root->fs_info;
-	struct btrfs_path *path;
-	struct pending_extent_op *extent_op, *tmp;
-	struct list_head insert_list, update_list;
-	int ret;
-	int num_inserts = 0, max_inserts, restart = 0;
-
-	path = btrfs_alloc_path();
-	INIT_LIST_HEAD(&insert_list);
-	INIT_LIST_HEAD(&update_list);
-
-	max_inserts = extent_root->leafsize /
-		(2 * sizeof(struct btrfs_key) + 2 * sizeof(struct btrfs_item) +
-		 sizeof(struct btrfs_extent_ref) +
-		 sizeof(struct btrfs_extent_item));
-again:
-	mutex_lock(&info->extent_ins_mutex);
-	while (1) {
-		ret = find_first_extent_bit(&info->extent_ins, search, &start,
-					    &end, EXTENT_WRITEBACK);
-		if (ret) {
-			if (restart && !num_inserts &&
-			    list_empty(&update_list)) {
-				restart = 0;
-				search = 0;
-				continue;
-			}
-			break;
-		}
-
-		ret = try_lock_extent(&info->extent_ins, start, end, GFP_NOFS);
-		if (!ret) {
-			if (all)
-				restart = 1;
-			search = end + 1;
-			if (need_resched()) {
-				mutex_unlock(&info->extent_ins_mutex);
-				cond_resched();
-				mutex_lock(&info->extent_ins_mutex);
-			}
-			continue;
-		}
-
-		ret = get_state_private(&info->extent_ins, start, &priv);
-		BUG_ON(ret);
-		extent_op = (struct pending_extent_op *)(unsigned long) priv;
-
-		if (extent_op->type == PENDING_EXTENT_INSERT) {
-			num_inserts++;
-			list_add_tail(&extent_op->list, &insert_list);
-			search = end + 1;
-			if (num_inserts == max_inserts) {
-				restart = 1;
-				break;
-			}
-		} else if (extent_op->type == PENDING_BACKREF_UPDATE) {
-			list_add_tail(&extent_op->list, &update_list);
-			search = end + 1;
-		} else {
-			BUG();
-		}
-	}
-
-	/*
-	 * process the update list, clear the writeback bit for it, and if
-	 * somebody marked this thing for deletion then just unlock it and be
-	 * done, the free_extents will handle it
-	 */
-	list_for_each_entry_safe(extent_op, tmp, &update_list, list) {
-		clear_extent_bits(&info->extent_ins, extent_op->bytenr,
-				  extent_op->bytenr + extent_op->num_bytes - 1,
-				  EXTENT_WRITEBACK, GFP_NOFS);
-		if (extent_op->del) {
-			list_del_init(&extent_op->list);
-			unlock_extent(&info->extent_ins, extent_op->bytenr,
-				      extent_op->bytenr + extent_op->num_bytes
-				      - 1, GFP_NOFS);
-			kfree(extent_op);
-		}
-	}
-	mutex_unlock(&info->extent_ins_mutex);
-
-	/*
-	 * still have things left on the update list, go ahead an update
-	 * everything
-	 */
-	if (!list_empty(&update_list)) {
-		ret = update_backrefs(trans, extent_root, path, &update_list);
-		BUG_ON(ret);
-
-		/* we may have COW'ed new blocks, so lets start over */
-		if (all)
-			restart = 1;
-	}
-
-	/*
-	 * if no inserts need to be done, but we skipped some extents and we
-	 * need to make sure everything is cleaned then reset everything and
-	 * go back to the beginning
-	 */
-	if (!num_inserts && restart) {
-		search = 0;
-		restart = 0;
-		INIT_LIST_HEAD(&update_list);
-		INIT_LIST_HEAD(&insert_list);
-		goto again;
-	} else if (!num_inserts) {
-		goto out;
-	}
-
-	/*
-	 * process the insert extents list.  Again if we are deleting this
-	 * extent, then just unlock it, pin down the bytes if need be, and be
-	 * done with it.  Saves us from having to actually insert the extent
-	 * into the tree and then subsequently come along and delete it
-	 */
-	mutex_lock(&info->extent_ins_mutex);
-	list_for_each_entry_safe(extent_op, tmp, &insert_list, list) {
-		clear_extent_bits(&info->extent_ins, extent_op->bytenr,
-				  extent_op->bytenr + extent_op->num_bytes - 1,
-				  EXTENT_WRITEBACK, GFP_NOFS);
-		if (extent_op->del) {
-			u64 used;
-			list_del_init(&extent_op->list);
-			unlock_extent(&info->extent_ins, extent_op->bytenr,
-				      extent_op->bytenr + extent_op->num_bytes
-				      - 1, GFP_NOFS);
-
-			mutex_lock(&extent_root->fs_info->pinned_mutex);
-			ret = pin_down_bytes(trans, extent_root,
-					     extent_op->bytenr,
-					     extent_op->num_bytes, 0);
-			mutex_unlock(&extent_root->fs_info->pinned_mutex);
-
-			spin_lock(&info->delalloc_lock);
-			used = btrfs_super_bytes_used(&info->super_copy);
-			btrfs_set_super_bytes_used(&info->super_copy,
-					used - extent_op->num_bytes);
-			used = btrfs_root_used(&extent_root->root_item);
-			btrfs_set_root_used(&extent_root->root_item,
-					used - extent_op->num_bytes);
-			spin_unlock(&info->delalloc_lock);
-
-			ret = update_block_group(trans, extent_root,
-						 extent_op->bytenr,
-						 extent_op->num_bytes,
-						 0, ret > 0);
-			BUG_ON(ret);
-			kfree(extent_op);
-			num_inserts--;
-		}
-	}
-	mutex_unlock(&info->extent_ins_mutex);
-
-	ret = insert_extents(trans, extent_root, path, &insert_list,
-			     num_inserts);
-	BUG_ON(ret);
-
-	/*
-	 * if restart is set for whatever reason we need to go back and start
-	 * searching through the pending list again.
-	 *
-	 * We just inserted some extents, which could have resulted in new
-	 * blocks being allocated, which would result in new blocks needing
-	 * updates, so if all is set we _must_ restart to get the updated
-	 * blocks.
-	 */
-	if (restart || all) {
-		INIT_LIST_HEAD(&insert_list);
-		INIT_LIST_HEAD(&update_list);
-		search = 0;
-		restart = 0;
-		num_inserts = 0;
-		goto again;
-	}
-out:
-	btrfs_free_path(path);
-	return 0;
-}
-
 static int pin_down_bytes(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  u64 bytenr, u64 num_bytes, int is_data)
@@ -2686,6 +2155,7 @@
 		u64 header_transid = btrfs_header_generation(buf);
 		if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
 		    header_owner != BTRFS_TREE_RELOC_OBJECTID &&
+		    header_owner != BTRFS_DATA_RELOC_TREE_OBJECTID &&
 		    header_transid == trans->transid &&
 		    !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 			clean_tree_block(NULL, root, buf);
@@ -2710,7 +2180,8 @@
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
 			 u64 root_objectid, u64 ref_generation,
-			 u64 owner_objectid, int pin, int mark_free)
+			 u64 owner_objectid, int pin, int mark_free,
+			 int refs_to_drop)
 {
 	struct btrfs_path *path;
 	struct btrfs_key key;
@@ -2753,7 +2224,8 @@
 				break;
 		}
 		if (!found_extent) {
-			ret = remove_extent_backref(trans, extent_root, path);
+			ret = remove_extent_backref(trans, extent_root, path,
+						    refs_to_drop);
 			BUG_ON(ret);
 			btrfs_release_path(extent_root, path);
 			ret = btrfs_search_slot(trans, extent_root,
@@ -2771,8 +2243,9 @@
 		btrfs_print_leaf(extent_root, path->nodes[0]);
 		WARN_ON(1);
 		printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
-		       "root %llu gen %llu owner %llu\n",
+		       "parent %llu root %llu gen %llu owner %llu\n",
 		       (unsigned long long)bytenr,
+		       (unsigned long long)parent,
 		       (unsigned long long)root_objectid,
 		       (unsigned long long)ref_generation,
 		       (unsigned long long)owner_objectid);
@@ -2782,17 +2255,23 @@
 	ei = btrfs_item_ptr(leaf, extent_slot,
 			    struct btrfs_extent_item);
 	refs = btrfs_extent_refs(leaf, ei);
-	BUG_ON(refs == 0);
-	refs -= 1;
-	btrfs_set_extent_refs(leaf, ei, refs);
 
+	/*
+	 * we're not allowed to delete the extent item if there
+	 * are other delayed ref updates pending
+	 */
+
+	BUG_ON(refs < refs_to_drop);
+	refs -= refs_to_drop;
+	btrfs_set_extent_refs(leaf, ei, refs);
 	btrfs_mark_buffer_dirty(leaf);
 
-	if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
+	if (refs == 0 && found_extent &&
+	    path->slots[0] == extent_slot + 1) {
 		struct btrfs_extent_ref *ref;
 		ref = btrfs_item_ptr(leaf, path->slots[0],
 				     struct btrfs_extent_ref);
-		BUG_ON(btrfs_ref_num_refs(leaf, ref) != 1);
+		BUG_ON(btrfs_ref_num_refs(leaf, ref) != refs_to_drop);
 		/* if the back ref and the extent are next to each other
 		 * they get deleted below in one shot
 		 */
@@ -2800,7 +2279,8 @@
 		num_to_del = 2;
 	} else if (found_extent) {
 		/* otherwise delete the extent back ref */
-		ret = remove_extent_backref(trans, extent_root, path);
+		ret = remove_extent_backref(trans, extent_root, path,
+					    refs_to_drop);
 		BUG_ON(ret);
 		/* if refs are 0, we need to setup the path for deletion */
 		if (refs == 0) {
@@ -2850,218 +2330,35 @@
 		BUG_ON(ret);
 	}
 	btrfs_free_path(path);
-	finish_current_insert(trans, extent_root, 0);
 	return ret;
 }
 
 /*
- * find all the blocks marked as pending in the radix tree and remove
- * them from the extent map
- */
-static int del_pending_extents(struct btrfs_trans_handle *trans,
-			       struct btrfs_root *extent_root, int all)
-{
-	int ret;
-	int err = 0;
-	u64 start;
-	u64 end;
-	u64 priv;
-	u64 search = 0;
-	int nr = 0, skipped = 0;
-	struct extent_io_tree *pending_del;
-	struct extent_io_tree *extent_ins;
-	struct pending_extent_op *extent_op;
-	struct btrfs_fs_info *info = extent_root->fs_info;
-	struct list_head delete_list;
-
-	INIT_LIST_HEAD(&delete_list);
-	extent_ins = &extent_root->fs_info->extent_ins;
-	pending_del = &extent_root->fs_info->pending_del;
-
-again:
-	mutex_lock(&info->extent_ins_mutex);
-	while (1) {
-		ret = find_first_extent_bit(pending_del, search, &start, &end,
-					    EXTENT_WRITEBACK);
-		if (ret) {
-			if (all && skipped && !nr) {
-				search = 0;
-				skipped = 0;
-				continue;
-			}
-			mutex_unlock(&info->extent_ins_mutex);
-			break;
-		}
-
-		ret = try_lock_extent(extent_ins, start, end, GFP_NOFS);
-		if (!ret) {
-			search = end+1;
-			skipped = 1;
-
-			if (need_resched()) {
-				mutex_unlock(&info->extent_ins_mutex);
-				cond_resched();
-				mutex_lock(&info->extent_ins_mutex);
-			}
-
-			continue;
-		}
-		BUG_ON(ret < 0);
-
-		ret = get_state_private(pending_del, start, &priv);
-		BUG_ON(ret);
-		extent_op = (struct pending_extent_op *)(unsigned long)priv;
-
-		clear_extent_bits(pending_del, start, end, EXTENT_WRITEBACK,
-				  GFP_NOFS);
-		if (!test_range_bit(extent_ins, start, end,
-				    EXTENT_WRITEBACK, 0)) {
-			list_add_tail(&extent_op->list, &delete_list);
-			nr++;
-		} else {
-			kfree(extent_op);
-
-			ret = get_state_private(&info->extent_ins, start,
-						&priv);
-			BUG_ON(ret);
-			extent_op = (struct pending_extent_op *)
-						(unsigned long)priv;
-
-			clear_extent_bits(&info->extent_ins, start, end,
-					  EXTENT_WRITEBACK, GFP_NOFS);
-
-			if (extent_op->type == PENDING_BACKREF_UPDATE) {
-				list_add_tail(&extent_op->list, &delete_list);
-				search = end + 1;
-				nr++;
-				continue;
-			}
-
-			mutex_lock(&extent_root->fs_info->pinned_mutex);
-			ret = pin_down_bytes(trans, extent_root, start,
-					     end + 1 - start, 0);
-			mutex_unlock(&extent_root->fs_info->pinned_mutex);
-
-			ret = update_block_group(trans, extent_root, start,
-						end + 1 - start, 0, ret > 0);
-
-			unlock_extent(extent_ins, start, end, GFP_NOFS);
-			BUG_ON(ret);
-			kfree(extent_op);
-		}
-		if (ret)
-			err = ret;
-
-		search = end + 1;
-
-		if (need_resched()) {
-			mutex_unlock(&info->extent_ins_mutex);
-			cond_resched();
-			mutex_lock(&info->extent_ins_mutex);
-		}
-	}
-
-	if (nr) {
-		ret = free_extents(trans, extent_root, &delete_list);
-		BUG_ON(ret);
-	}
-
-	if (all && skipped) {
-		INIT_LIST_HEAD(&delete_list);
-		search = 0;
-		nr = 0;
-		goto again;
-	}
-
-	if (!err)
-		finish_current_insert(trans, extent_root, 0);
-	return err;
-}
-
-/*
  * remove an extent from the root, returns 0 on success
  */
 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
-			       struct btrfs_root *root,
-			       u64 bytenr, u64 num_bytes, u64 parent,
-			       u64 root_objectid, u64 ref_generation,
-			       u64 owner_objectid, int pin)
+					struct btrfs_root *root,
+					u64 bytenr, u64 num_bytes, u64 parent,
+					u64 root_objectid, u64 ref_generation,
+					u64 owner_objectid, int pin,
+					int refs_to_drop)
 {
-	struct btrfs_root *extent_root = root->fs_info->extent_root;
-	int pending_ret;
-	int ret;
-
 	WARN_ON(num_bytes < root->sectorsize);
-	if (root == extent_root) {
-		struct pending_extent_op *extent_op = NULL;
 
-		mutex_lock(&root->fs_info->extent_ins_mutex);
-		if (test_range_bit(&root->fs_info->extent_ins, bytenr,
-				bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
-			u64 priv;
-			ret = get_state_private(&root->fs_info->extent_ins,
-						bytenr, &priv);
-			BUG_ON(ret);
-			extent_op = (struct pending_extent_op *)
-						(unsigned long)priv;
-
-			extent_op->del = 1;
-			if (extent_op->type == PENDING_EXTENT_INSERT) {
-				mutex_unlock(&root->fs_info->extent_ins_mutex);
-				return 0;
-			}
-		}
-
-		if (extent_op) {
-			ref_generation = extent_op->orig_generation;
-			parent = extent_op->orig_parent;
-		}
-
-		extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
-		BUG_ON(!extent_op);
-
-		extent_op->type = PENDING_EXTENT_DELETE;
-		extent_op->bytenr = bytenr;
-		extent_op->num_bytes = num_bytes;
-		extent_op->parent = parent;
-		extent_op->orig_parent = parent;
-		extent_op->generation = ref_generation;
-		extent_op->orig_generation = ref_generation;
-		extent_op->level = (int)owner_objectid;
-		INIT_LIST_HEAD(&extent_op->list);
-		extent_op->del = 0;
-
-		set_extent_bits(&root->fs_info->pending_del,
-				bytenr, bytenr + num_bytes - 1,
-				EXTENT_WRITEBACK, GFP_NOFS);
-		set_state_private(&root->fs_info->pending_del,
-				  bytenr, (unsigned long)extent_op);
-		mutex_unlock(&root->fs_info->extent_ins_mutex);
-		return 0;
-	}
-	/* if metadata always pin */
-	if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
-		if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
-			mutex_lock(&root->fs_info->pinned_mutex);
-			btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
-			mutex_unlock(&root->fs_info->pinned_mutex);
-			update_reserved_extents(root, bytenr, num_bytes, 0);
-			return 0;
-		}
+	/*
+	 * if metadata always pin
+	 * if data pin when any transaction has committed this
+	 */
+	if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID ||
+	    ref_generation != trans->transid)
 		pin = 1;
-	}
 
-	/* if data pin when any transaction has committed this */
 	if (ref_generation != trans->transid)
 		pin = 1;
 
-	ret = __free_extent(trans, root, bytenr, num_bytes, parent,
+	return __free_extent(trans, root, bytenr, num_bytes, parent,
 			    root_objectid, ref_generation,
-			    owner_objectid, pin, pin == 0);
-
-	finish_current_insert(trans, root->fs_info->extent_root, 0);
-	pending_ret = del_pending_extents(trans, root->fs_info->extent_root, 0);
-	return ret ? ret : pending_ret;
+			    owner_objectid, pin, pin == 0, refs_to_drop);
 }
 
 int btrfs_free_extent(struct btrfs_trans_handle *trans,
@@ -3072,9 +2369,26 @@
 {
 	int ret;
 
-	ret = __btrfs_free_extent(trans, root, bytenr, num_bytes, parent,
-				  root_objectid, ref_generation,
-				  owner_objectid, pin);
+	/*
+	 * tree log blocks never actually go into the extent allocation
+	 * tree, just update pinning info and exit early.
+	 *
+	 * data extents referenced by the tree log do need to have
+	 * their reference counts bumped.
+	 */
+	if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID &&
+	    owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
+		mutex_lock(&root->fs_info->pinned_mutex);
+		btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
+		mutex_unlock(&root->fs_info->pinned_mutex);
+		update_reserved_extents(root, bytenr, num_bytes, 0);
+		ret = 0;
+	} else {
+		ret = btrfs_add_delayed_ref(trans, bytenr, num_bytes, parent,
+				       root_objectid, ref_generation,
+				       owner_objectid,
+				       BTRFS_DROP_DELAYED_REF, 1);
+	}
 	return ret;
 }
 
@@ -3475,10 +2789,10 @@
 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
 					 struct btrfs_root *root, u64 parent,
 					 u64 root_objectid, u64 ref_generation,
-					 u64 owner, struct btrfs_key *ins)
+					 u64 owner, struct btrfs_key *ins,
+					 int ref_mod)
 {
 	int ret;
-	int pending_ret;
 	u64 super_used;
 	u64 root_used;
 	u64 num_bytes = ins->offset;
@@ -3503,33 +2817,6 @@
 	btrfs_set_root_used(&root->root_item, root_used + num_bytes);
 	spin_unlock(&info->delalloc_lock);
 
-	if (root == extent_root) {
-		struct pending_extent_op *extent_op;
-
-		extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
-		BUG_ON(!extent_op);
-
-		extent_op->type = PENDING_EXTENT_INSERT;
-		extent_op->bytenr = ins->objectid;
-		extent_op->num_bytes = ins->offset;
-		extent_op->parent = parent;
-		extent_op->orig_parent = 0;
-		extent_op->generation = ref_generation;
-		extent_op->orig_generation = 0;
-		extent_op->level = (int)owner;
-		INIT_LIST_HEAD(&extent_op->list);
-		extent_op->del = 0;
-
-		mutex_lock(&root->fs_info->extent_ins_mutex);
-		set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
-				ins->objectid + ins->offset - 1,
-				EXTENT_WRITEBACK, GFP_NOFS);
-		set_state_private(&root->fs_info->extent_ins,
-				  ins->objectid, (unsigned long)extent_op);
-		mutex_unlock(&root->fs_info->extent_ins_mutex);
-		goto update_block;
-	}
-
 	memcpy(&keys[0], ins, sizeof(*ins));
 	keys[1].objectid = ins->objectid;
 	keys[1].type = BTRFS_EXTENT_REF_KEY;
@@ -3546,31 +2833,24 @@
 
 	extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 				     struct btrfs_extent_item);
-	btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
+	btrfs_set_extent_refs(path->nodes[0], extent_item, ref_mod);
 	ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
 			     struct btrfs_extent_ref);
 
 	btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
 	btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
 	btrfs_set_ref_objectid(path->nodes[0], ref, owner);
-	btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
+	btrfs_set_ref_num_refs(path->nodes[0], ref, ref_mod);
 
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 
 	trans->alloc_exclude_start = 0;
 	trans->alloc_exclude_nr = 0;
 	btrfs_free_path(path);
-	finish_current_insert(trans, extent_root, 0);
-	pending_ret = del_pending_extents(trans, extent_root, 0);
 
 	if (ret)
 		goto out;
-	if (pending_ret) {
-		ret = pending_ret;
-		goto out;
-	}
 
-update_block:
 	ret = update_block_group(trans, root, ins->objectid,
 				 ins->offset, 1, 0);
 	if (ret) {
@@ -3592,9 +2872,12 @@
 
 	if (root_objectid == BTRFS_TREE_LOG_OBJECTID)
 		return 0;
-	ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
-					    ref_generation, owner, ins);
-	update_reserved_extents(root, ins->objectid, ins->offset, 0);
+
+	ret = btrfs_add_delayed_ref(trans, ins->objectid,
+				    ins->offset, parent, root_objectid,
+				    ref_generation, owner,
+				    BTRFS_ADD_DELAYED_EXTENT, 0);
+	BUG_ON(ret);
 	return ret;
 }
 
@@ -3621,7 +2904,7 @@
 	BUG_ON(ret);
 	put_block_group(block_group);
 	ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
-					    ref_generation, owner, ins);
+					    ref_generation, owner, ins, 1);
 	return ret;
 }
 
@@ -3640,20 +2923,18 @@
 		       u64 search_end, struct btrfs_key *ins, u64 data)
 {
 	int ret;
-
 	ret = __btrfs_reserve_extent(trans, root, num_bytes,
 				     min_alloc_size, empty_size, hint_byte,
 				     search_end, ins, data);
 	BUG_ON(ret);
 	if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
-		ret = __btrfs_alloc_reserved_extent(trans, root, parent,
-					root_objectid, ref_generation,
-					owner_objectid, ins);
+		ret = btrfs_add_delayed_ref(trans, ins->objectid,
+					    ins->offset, parent, root_objectid,
+					    ref_generation, owner_objectid,
+					    BTRFS_ADD_DELAYED_EXTENT, 0);
 		BUG_ON(ret);
-
-	} else {
-		update_reserved_extents(root, ins->objectid, ins->offset, 1);
 	}
+	update_reserved_extents(root, ins->objectid, ins->offset, 1);
 	return ret;
 }
 
@@ -3789,7 +3070,7 @@
 
 		fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 
-		ret = __btrfs_free_extent(trans, root, disk_bytenr,
+		ret = btrfs_free_extent(trans, root, disk_bytenr,
 				btrfs_file_extent_disk_num_bytes(leaf, fi),
 				leaf->start, leaf_owner, leaf_generation,
 				key.objectid, 0);
@@ -3829,7 +3110,7 @@
 	 */
 	for (i = 0; i < ref->nritems; i++) {
 		info = ref->extents + sorted[i].slot;
-		ret = __btrfs_free_extent(trans, root, info->bytenr,
+		ret = btrfs_free_extent(trans, root, info->bytenr,
 					  info->num_bytes, ref->bytenr,
 					  ref->owner, ref->generation,
 					  info->objectid, 0);
@@ -3846,12 +3127,13 @@
 	return 0;
 }
 
-static int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start,
+static int drop_snap_lookup_refcount(struct btrfs_trans_handle *trans,
+				     struct btrfs_root *root, u64 start,
 				     u64 len, u32 *refs)
 {
 	int ret;
 
-	ret = btrfs_lookup_extent_ref(NULL, root, start, len, refs);
+	ret = btrfs_lookup_extent_ref(trans, root, start, len, refs);
 	BUG_ON(ret);
 
 #if 0 /* some debugging code in case we see problems here */
@@ -3959,7 +3241,8 @@
 		 * we just decrement it below and don't update any
 		 * of the refs the leaf points to.
 		 */
-		ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
+		ret = drop_snap_lookup_refcount(trans, root, bytenr,
+						blocksize, &refs);
 		BUG_ON(ret);
 		if (refs != 1)
 			continue;
@@ -4010,7 +3293,7 @@
 	 */
 	for (i = 0; i < refi; i++) {
 		bytenr = sorted[i].bytenr;
-		ret = __btrfs_free_extent(trans, root, bytenr,
+		ret = btrfs_free_extent(trans, root, bytenr,
 					blocksize, eb->start,
 					root_owner, root_gen, 0, 1);
 		BUG_ON(ret);
@@ -4053,7 +3336,7 @@
 
 	WARN_ON(*level < 0);
 	WARN_ON(*level >= BTRFS_MAX_LEVEL);
-	ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
+	ret = drop_snap_lookup_refcount(trans, root, path->nodes[*level]->start,
 				path->nodes[*level]->len, &refs);
 	BUG_ON(ret);
 	if (refs > 1)
@@ -4104,7 +3387,8 @@
 		ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
 		blocksize = btrfs_level_size(root, *level - 1);
 
-		ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
+		ret = drop_snap_lookup_refcount(trans, root, bytenr,
+						blocksize, &refs);
 		BUG_ON(ret);
 
 		/*
@@ -4119,7 +3403,7 @@
 			root_gen = btrfs_header_generation(parent);
 			path->slots[*level]++;
 
-			ret = __btrfs_free_extent(trans, root, bytenr,
+			ret = btrfs_free_extent(trans, root, bytenr,
 						blocksize, parent->start,
 						root_owner, root_gen,
 						*level - 1, 1);
@@ -4165,7 +3449,7 @@
 	 * cleanup and free the reference on the last node
 	 * we processed
 	 */
-	ret = __btrfs_free_extent(trans, root, bytenr, blocksize,
+	ret = btrfs_free_extent(trans, root, bytenr, blocksize,
 				  parent->start, root_owner, root_gen,
 				  *level, 1);
 	free_extent_buffer(path->nodes[*level]);
@@ -5457,6 +4741,7 @@
 					root->root_key.objectid,
 					trans->transid, key.objectid);
 		BUG_ON(ret);
+
 		ret = btrfs_free_extent(trans, root,
 					bytenr, num_bytes, leaf->start,
 					btrfs_header_owner(leaf),
@@ -5768,9 +5053,6 @@
 				ref_path, NULL, NULL);
 	BUG_ON(ret);
 
-	if (root == root->fs_info->extent_root)
-		btrfs_extent_post_op(trans, root);
-
 	return 0;
 }
 
@@ -6208,6 +5490,9 @@
 	btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
 	mutex_unlock(&root->fs_info->cleaner_mutex);
 
+	trans = btrfs_start_transaction(info->tree_root, 1);
+	btrfs_commit_transaction(trans, info->tree_root);
+
 	while (1) {
 		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 		if (ret < 0)
@@ -6500,9 +5785,6 @@
 				sizeof(cache->item));
 	BUG_ON(ret);
 
-	finish_current_insert(trans, extent_root, 0);
-	ret = del_pending_extents(trans, extent_root, 0);
-	BUG_ON(ret);
 	set_avail_alloc_bits(extent_root->fs_info, type);
 
 	return 0;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index dc78954..c800754 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -643,7 +643,9 @@
 
 			if (disk_bytenr != 0) {
 				ret = btrfs_update_extent_ref(trans, root,
-						disk_bytenr, orig_parent,
+						disk_bytenr,
+						le64_to_cpu(old.disk_num_bytes),
+						orig_parent,
 						leaf->start,
 						root->root_key.objectid,
 						trans->transid, ins.objectid);
@@ -912,7 +914,7 @@
 	btrfs_set_file_extent_other_encoding(leaf, fi, 0);
 
 	if (orig_parent != leaf->start) {
-		ret = btrfs_update_extent_ref(trans, root, bytenr,
+		ret = btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
 					      orig_parent, leaf->start,
 					      root->root_key.objectid,
 					      trans->transid, inode->i_ino);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index d638c54..f94c2ad 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -65,6 +65,12 @@
 		cur_trans->use_count = 1;
 		cur_trans->commit_done = 0;
 		cur_trans->start_time = get_seconds();
+
+		cur_trans->delayed_refs.root.rb_node = NULL;
+		cur_trans->delayed_refs.num_entries = 0;
+		cur_trans->delayed_refs.flushing = 0;
+		spin_lock_init(&cur_trans->delayed_refs.lock);
+
 		INIT_LIST_HEAD(&cur_trans->pending_snapshots);
 		list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
 		extent_io_tree_init(&cur_trans->dirty_pages,
@@ -182,6 +188,7 @@
 	h->block_group = 0;
 	h->alloc_exclude_nr = 0;
 	h->alloc_exclude_start = 0;
+	h->delayed_ref_updates = 0;
 	root->fs_info->running_transaction->use_count++;
 	mutex_unlock(&root->fs_info->trans_mutex);
 	return h;
@@ -281,6 +288,14 @@
 	struct btrfs_transaction *cur_trans;
 	struct btrfs_fs_info *info = root->fs_info;
 
+	if (trans->delayed_ref_updates &&
+	    (trans->transaction->delayed_refs.flushing ||
+	    trans->transaction->delayed_refs.num_entries > 16384)) {
+		btrfs_run_delayed_refs(trans, root, trans->delayed_ref_updates);
+	} else if (trans->transaction->delayed_refs.num_entries > 64) {
+		wake_up_process(root->fs_info->transaction_kthread);
+	}
+
 	mutex_lock(&info->trans_mutex);
 	cur_trans = info->running_transaction;
 	WARN_ON(cur_trans != trans->transaction);
@@ -424,9 +439,10 @@
 	u64 old_root_bytenr;
 	struct btrfs_root *tree_root = root->fs_info->tree_root;
 
-	btrfs_extent_post_op(trans, root);
 	btrfs_write_dirty_block_groups(trans, root);
-	btrfs_extent_post_op(trans, root);
+
+	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+	BUG_ON(ret);
 
 	while (1) {
 		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
@@ -438,14 +454,14 @@
 				     btrfs_header_level(root->node));
 		btrfs_set_root_generation(&root->root_item, trans->transid);
 
-		btrfs_extent_post_op(trans, root);
-
 		ret = btrfs_update_root(trans, tree_root,
 					&root->root_key,
 					&root->root_item);
 		BUG_ON(ret);
 		btrfs_write_dirty_block_groups(trans, root);
-		btrfs_extent_post_op(trans, root);
+
+		ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+		BUG_ON(ret);
 	}
 	return 0;
 }
@@ -459,15 +475,18 @@
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct list_head *next;
 	struct extent_buffer *eb;
+	int ret;
 
-	btrfs_extent_post_op(trans, fs_info->tree_root);
+	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+	BUG_ON(ret);
 
 	eb = btrfs_lock_root_node(fs_info->tree_root);
 	btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
 	btrfs_tree_unlock(eb);
 	free_extent_buffer(eb);
 
-	btrfs_extent_post_op(trans, fs_info->tree_root);
+	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+	BUG_ON(ret);
 
 	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
 		next = fs_info->dirty_cowonly_roots.next;
@@ -475,6 +494,9 @@
 		root = list_entry(next, struct btrfs_root, dirty_list);
 
 		update_cowonly_root(trans, root);
+
+		ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+		BUG_ON(ret);
 	}
 	return 0;
 }
@@ -895,6 +917,21 @@
 	DEFINE_WAIT(wait);
 	int ret;
 
+	/* make a pass through all the delayed refs we have so far
+	 * any runnings procs may add more while we are here
+	 */
+	ret = btrfs_run_delayed_refs(trans, root, 0);
+	BUG_ON(ret);
+
+	/*
+	 * set the flushing flag so procs in this transaction have to
+	 * start sending their work down.
+	 */
+	trans->transaction->delayed_refs.flushing = 1;
+
+	ret = btrfs_run_delayed_refs(trans, root, (u64)-1);
+	BUG_ON(ret);
+
 	INIT_LIST_HEAD(&dirty_fs_roots);
 	mutex_lock(&root->fs_info->trans_mutex);
 	if (trans->transaction->in_commit) {
@@ -969,6 +1006,9 @@
 	ret = create_pending_snapshots(trans, root->fs_info);
 	BUG_ON(ret);
 
+	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+	BUG_ON(ret);
+
 	WARN_ON(cur_trans != trans->transaction);
 
 	/* btrfs_commit_tree_roots is responsible for getting the
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index ea29211..9487670 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -19,6 +19,7 @@
 #ifndef __BTRFS_TRANSACTION__
 #define __BTRFS_TRANSACTION__
 #include "btrfs_inode.h"
+#include "delayed-ref.h"
 
 struct btrfs_transaction {
 	u64 transid;
@@ -34,6 +35,7 @@
 	wait_queue_head_t writer_wait;
 	wait_queue_head_t commit_wait;
 	struct list_head pending_snapshots;
+	struct btrfs_delayed_ref_root delayed_refs;
 };
 
 struct btrfs_trans_handle {
@@ -44,6 +46,7 @@
 	u64 block_group;
 	u64 alloc_exclude_start;
 	u64 alloc_exclude_nr;
+	unsigned long delayed_ref_updates;
 };
 
 struct btrfs_pending_snapshot {
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index 98d25fa..b10eacd 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -124,8 +124,6 @@
 	}
 
 	btrfs_release_path(root, path);
-	if (is_extent)
-		btrfs_extent_post_op(trans, root);
 out:
 	if (path)
 		btrfs_free_path(path);