struct radix_tree_root block_group_data_radix;
        struct radix_tree_root extent_map_radix;
 
-       u64 extent_tree_insert[BTRFS_MAX_LEVEL * 3];
+       u64 extent_tree_insert[BTRFS_MAX_LEVEL * 6];
        int extent_tree_insert_nr;
-       u64 extent_tree_prealloc[BTRFS_MAX_LEVEL * 3];
+       u64 extent_tree_prealloc[BTRFS_MAX_LEVEL * 6];
        int extent_tree_prealloc_nr;
 
        u64 generation;
 
        if (num_blocks == 0) {
                fill_prealloc = 1;
                num_blocks = 1;
-               total_needed = (min(level + 1, BTRFS_MAX_LEVEL) + 2) * 3;
+               total_needed = (min(level + 1, BTRFS_MAX_LEVEL)) * 6;
        }
        if (fill_prealloc) {
                u64 first;
                        ins->objectid;
                ret = update_block_group(trans, root,
                                         ins->objectid, ins->offset, 1, 0, 0);
+               WARN_ON(info->extent_tree_insert_nr >
+                       ARRAY_SIZE(info->extent_tree_insert));
                BUG_ON(ret);
                return 0;
        }
                if (wret < 0)
                        ret = wret;
                num_walks++;
-               if (num_walks > 10) {
+               if (num_walks > 2) {
                        ret = -EAGAIN;
                        get_bh(root->node);
                        break;
 
                                mutex_unlock(&info->fs_mutex);
 
                                btrfs_btree_balance_dirty(root);
+                               cond_resched();
 
                                mutex_lock(&info->fs_mutex);
                                trans = btrfs_start_transaction(tree_root, 1);
                                ret = err;
                        ret = btrfs_end_transaction(trans, tree_root);
                        BUG_ON(ret);
+                       mutex_unlock(&tree_root->fs_info->fs_mutex);
+
+                       btrfs_btree_balance_dirty(tree_root);
+                       schedule();
+
+                       mutex_lock(&tree_root->fs_info->fs_mutex);
                }
                BUG_ON(ret);
                ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
                kfree(dirty);
                mutex_unlock(&tree_root->fs_info->fs_mutex);
                btrfs_btree_balance_dirty(tree_root);
+               schedule();
        }
        return ret;
 }