+ spin_unlock(&root->fs_info->trans_lock);
+
+ cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
+ if (!cur_trans)
+ return -ENOMEM;
+ spin_lock(&root->fs_info->trans_lock);
+ if (root->fs_info->running_transaction) {
+ kmem_cache_free(btrfs_transaction_cachep, cur_trans);
+ cur_trans = root->fs_info->running_transaction;
+ atomic_inc(&cur_trans->use_count);
+ atomic_inc(&cur_trans->num_writers);
+ cur_trans->num_joined++;
+ spin_unlock(&root->fs_info->trans_lock);
+ return 0;
+ }
+ atomic_set(&cur_trans->num_writers, 1);
+ cur_trans->num_joined = 0;
+ init_waitqueue_head(&cur_trans->writer_wait);
+ init_waitqueue_head(&cur_trans->commit_wait);
+ cur_trans->in_commit = 0;
+ cur_trans->blocked = 0;
+ /*
+ * One for this trans handle, one so it will live on until we
+ * commit the transaction.
+ */
+ atomic_set(&cur_trans->use_count, 2);
+ cur_trans->commit_done = 0;
+ cur_trans->start_time = get_seconds();
+
+ cur_trans->delayed_refs.root = RB_ROOT;
+ cur_trans->delayed_refs.num_entries = 0;
+ cur_trans->delayed_refs.num_heads_ready = 0;
+ cur_trans->delayed_refs.num_heads = 0;
+ cur_trans->delayed_refs.flushing = 0;
+ cur_trans->delayed_refs.run_delayed_start = 0;
+ spin_lock_init(&cur_trans->commit_lock);
+ 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,
+ root->fs_info->btree_inode->i_mapping);
+ root->fs_info->generation++;
+ cur_trans->transid = root->fs_info->generation;
+ root->fs_info->running_transaction = cur_trans;
+ spin_unlock(&root->fs_info->trans_lock);