On 09/14/2012 08:41 PM, Josef Bacik wrote: > On Fri, Sep 14, 2012 at 02:58:04AM -0600, Liu Bo wrote: >> In some workloads we have nested joining transaction operations, >> eg. >> run_delalloc_nocow >> btrfs_join_transaction >> cow_file_range >> btrfs_join_transaction >> >> it can be a serious bug since each trans handler has only two >> block_rsv, orig_rsv and block_rsv, which means we may lose our >> first block_rsv after two joining transaction operations: >> >> 1) btrfs_start_transaction >> trans->block_rsv = A >> >> 2) btrfs_join_transaction >> trans->orig_rsv = trans->block_rsv; ---> orig_rsv is now A >> trans->block_rsv = B >> >> 3) btrfs_join_transaction >> trans->orig_rsv = trans->block_rsv; ---> orig_rsv is now B >> trans->block_rsv = C >> ... >> > > I'd like to see the actual stack trace where this happens, because I don't think > it can happen. And if it is we need to look at that specific case and adjust it > as necessary and not add a bunch of kmallocs just to track the block_rsv, > because frankly it's not that big of a deal, it was just put into place in case > somebody wasn't expecting a call they made to start another transaction and > reset the block_rsv, which I don't actually think happens anywhere. So NAK on > this patch, give me more information so I can figure out the right way to deal > with this. Thanks, > Fine, please run xfstests 068 till it hits a BUG_ON inside either btrfs_delete_delayed_dir_index or btrfs_insert_delayed_dir_index. What I saw is that the orig_rsv and block_rsv is both delalloc_block_rsv, which is already lack of space. thanks, liubo > Josef > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
