1 files changed, 553 insertions, 1121 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fefe83ad205..f5e7cae63d8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -49,17 +49,23 @@ struct pending_extent_op {
 	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 pin_down_bytes(struct btrfs_trans_handle *trans,
-			  struct btrfs_root *root,
-			  u64 bytenr, u64 num_bytes, int is_data);
+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 update_block_group(struct btrfs_trans_handle *trans,
 			      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 +560,13 @@ out:
 	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 +586,10 @@ static noinline int insert_extent_backref(struct btrfs_trans_handle *trans,
 		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 +603,7 @@ static noinline int insert_extent_backref(struct btrfs_trans_handle *trans,
 
 		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 &&
@@ -857,6 +615,7 @@ static noinline int insert_extent_backref(struct btrfs_trans_handle *trans,
 	} else {
 		goto out;
 	}
+	btrfs_unlock_up_safe(path, 1);
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 out:
 	btrfs_release_path(root, path);
@@ -865,7 +624,8 @@ out:
 
 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 +635,8 @@ static noinline int remove_extent_backref(struct btrfs_trans_handle *trans,
 	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 +687,28 @@ static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 #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;
-
-	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);
+	int pin = owner_objectid < BTRFS_FIRST_FREE_OBJECTID;
 
-			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 +716,36 @@ int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 	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;
@@ -1286,17 +758,24 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 
 	path->reada = 1;
+	path->leave_spinning = 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);
-	if (ret < 0)
+	/* 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) {
+		btrfs_set_path_blocking(path);
 		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 +789,24 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	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_unlock_up_safe(path, 1);
+
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 
 	btrfs_release_path(root->fs_info->extent_root, path);
 
 	path->reada = 1;
+	path->leave_spinning = 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 +821,278 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	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)
+{
+	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)
 {
-	u64 start;
-	u64 end;
 	int ret;
+	struct btrfs_delayed_ref *ref;
+
+	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;
+	}
 
-	while(1) {
-		finish_current_insert(trans, root->fs_info->extent_root, 1);
-		del_pending_extents(trans, root->fs_info->extent_root, 1);
+	ref = btrfs_delayed_node_to_ref(node);
+	if (ref->action == BTRFS_ADD_DELAYED_REF) {
+		if (insert_reserved) {
+			struct btrfs_key ins;
 
-		/* 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;
+			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;
+	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);
+	}
+	if (action == BTRFS_ADD_DELAYED_REF) {
+		action = BTRFS_DROP_DELAYED_REF;
+		goto again;
+	}
+	return NULL;
+}
+
+static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
+				       struct btrfs_root *root,
+				       struct list_head *cluster)
+{
+	struct btrfs_delayed_ref_root *delayed_refs;
+	struct btrfs_delayed_ref_node *ref;
+	struct btrfs_delayed_ref_head *locked_ref = NULL;
 	int ret;
-	struct btrfs_key key;
-	struct extent_buffer *l;
-	struct btrfs_extent_item *item;
+	int count = 0;
+	int must_insert_reserved = 0;
 
-	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();
+	delayed_refs = &trans->transaction->delayed_refs;
+	while (1) {
+		if (!locked_ref) {
+			/* pick a new head ref from the cluster list */
+			if (list_empty(cluster))
+				break;
+
+			locked_ref = list_entry(cluster->next,
+				     struct btrfs_delayed_ref_head, cluster);
+
+			/* grab the lock that says we are going to process
+			 * all the refs for this head */
+			ret = btrfs_delayed_ref_lock(trans, locked_ref);
+
+			/*
+			 * we may have dropped the spin lock to get the head
+			 * mutex lock, and that might have given someone else
+			 * time to free the head.  If that's true, it has been
+			 * removed from our list and we can move on.
+			 */
+			if (ret == -EAGAIN) {
+				locked_ref = NULL;
+				count++;
+				continue;
+			}
+		}
+
+		/*
+		 * 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;
+			list_del_init(&locked_ref->cluster);
+			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);
+
+		count++;
+		cond_resched();
+		spin_lock(&delayed_refs->lock);
+	}
+	return count;
+}
+
+/*
+ * 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 list_head cluster;
+	int ret;
+	int run_all = count == (unsigned long)-1;
+	int run_most = 0;
+
+	if (root == root->fs_info->extent_root)
+		root = root->fs_info->tree_root;
+
+	delayed_refs = &trans->transaction->delayed_refs;
+	INIT_LIST_HEAD(&cluster);
+again:
+	spin_lock(&delayed_refs->lock);
+	if (count == 0) {
+		count = delayed_refs->num_entries * 2;
+		run_most = 1;
+	}
+	while (1) {
+		if (!(run_all || run_most) &&
+		    delayed_refs->num_heads_ready < 64)
+			break;
+
+		/*
+		 * go find something we can process in the rbtree.  We start at
+		 * the beginning of the tree, and then build a cluster
+		 * of refs to process starting at the first one we are able to
+		 * lock
+		 */
+		ret = btrfs_find_ref_cluster(trans, &cluster,
+					     delayed_refs->run_delayed_start);
+		if (ret)
+			break;
+
+		ret = run_clustered_refs(trans, root, &cluster);
+		BUG_ON(ret < 0);
+
+		count -= min_t(unsigned long, ret, count);
+
+		if (count == 0)
+			break;
+	}
+
+	if (run_all) {
+		node = rb_first(&delayed_refs->root);
+		if (!node)
+			goto out;
+		count = (unsigned long)-1;
+
+		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);
+				cond_resched();
+				goto again;
+			}
+			node = rb_next(node);
+		}
+		spin_unlock(&delayed_refs->lock);
+		schedule_timeout(1);
+		goto again;
 	}
-	l = path->nodes[0];
-	item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
-	*refs = btrfs_extent_refs(l, item);
 out:
-	btrfs_free_path(path);
+	spin_unlock(&delayed_refs->lock);
 	return 0;
 }
 
@@ -1624,7 +1316,7 @@ noinline int btrfs_inc_ref(struct btrfs_trans_handle *trans,
 	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 +1388,19 @@ noinline int btrfs_inc_ref(struct btrfs_trans_handle *trans,