BUG_ON(!wc);
 
        trans = btrfs_start_transaction(tree_root, 0);
+       BUG_ON(IS_ERR(trans));
+
        if (block_rsv)
                trans->block_rsv = block_rsv;
 
 
                        btrfs_end_transaction_throttle(trans, tree_root);
                        trans = btrfs_start_transaction(tree_root, 0);
+                       BUG_ON(IS_ERR(trans));
                        if (block_rsv)
                                trans->block_rsv = block_rsv;
                }
 
        if (found) {
                trans = btrfs_start_transaction(root, 1);
-               BUG_ON(!trans);
+               BUG_ON(IS_ERR(trans));
                ret = btrfs_commit_transaction(trans, root);
                BUG_ON(ret);
        }
 
 
        trans = btrfs_start_transaction(extent_root, 1);
-       BUG_ON(!trans);
+       BUG_ON(IS_ERR(trans));
 
        if (extent_key->objectid == 0) {
                ret = del_extent_zero(trans, extent_root, path, extent_key);
 
                 */
                if (is_bad_inode(inode)) {
                        trans = btrfs_start_transaction(root, 0);
+                       BUG_ON(IS_ERR(trans));
                        btrfs_orphan_del(trans, inode);
                        btrfs_end_transaction(trans, root);
                        iput(inode);
 
 
        if (new_size > old_size) {
                trans = btrfs_start_transaction(root, 0);
+               if (IS_ERR(trans)) {
+                       ret = PTR_ERR(trans);
+                       goto out_unlock;
+               }
                ret = btrfs_grow_device(trans, device, new_size);
                btrfs_commit_transaction(trans, root);
        } else {
        path->leave_spinning = 1;
 
        trans = btrfs_start_transaction(root, 1);
-       if (!trans) {
+       if (IS_ERR(trans)) {
                btrfs_free_path(path);
-               return -ENOMEM;
+               return PTR_ERR(trans);
        }
 
        dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
        u64 transid;
 
        trans = btrfs_start_transaction(root, 0);
+       if (IS_ERR(trans))
+               return PTR_ERR(trans);
        transid = trans->transid;
        btrfs_commit_transaction_async(trans, root, 0);
 
 
 
        while (1) {
                trans = btrfs_start_transaction(root, 0);
+               BUG_ON(IS_ERR(trans));
                trans->block_rsv = rc->block_rsv;
 
                ret = btrfs_block_rsv_check(trans, root, rc->block_rsv,
 
        while (1) {
                trans = btrfs_start_transaction(rc->extent_root, 0);
+               BUG_ON(IS_ERR(trans));
 
                if (update_backref_cache(trans, &rc->backref_cache)) {
                        btrfs_end_transaction(trans, rc->extent_root);
        int ret;
 
        trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
+       BUG_ON(IS_ERR(trans));
 
        memset(&root->root_item.drop_progress, 0,
                sizeof(root->root_item.drop_progress));
 
        btrfs_wait_ordered_extents(root, 0, 0);
 
        trans = btrfs_start_transaction(root, 0);
+       if (IS_ERR(trans))
+               return PTR_ERR(trans);
        ret = btrfs_commit_transaction(trans, root);
        return ret;
 }
 
        BUG_ON(!path);
 
        trans = btrfs_start_transaction(fs_info->tree_root, 0);
+       BUG_ON(IS_ERR(trans));
 
        wc.trans = trans;
        wc.pin = 1;
 
                return -ENOMEM;
 
        trans = btrfs_start_transaction(root, 0);
+       if (IS_ERR(trans)) {
+               btrfs_free_path(path);
+               return PTR_ERR(trans);
+       }
        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
        key.type = BTRFS_DEV_ITEM_KEY;
        key.offset = device->devid;
        }
 
        trans = btrfs_start_transaction(root, 0);
+       if (IS_ERR(trans)) {
+               kfree(device);
+               ret = PTR_ERR(trans);
+               goto error;
+       }
+
        lock_chunks(root);
 
        device->barriers = 1;
                return ret;
 
        trans = btrfs_start_transaction(root, 0);
-       BUG_ON(!trans);
+       BUG_ON(IS_ERR(trans));
 
        lock_chunks(root);
 
                BUG_ON(ret);
 
                trans = btrfs_start_transaction(dev_root, 0);
-               BUG_ON(!trans);
+               BUG_ON(IS_ERR(trans));
 
                ret = btrfs_grow_device(trans, device, old_size);
                BUG_ON(ret);
 
        /* Shrinking succeeded, else we would be at "done". */
        trans = btrfs_start_transaction(root, 0);
+       if (IS_ERR(trans)) {
+               ret = PTR_ERR(trans);
+               goto done;
+       }
+
        lock_chunks(root);
 
        device->disk_total_bytes = new_size;