On Wed 04-11-09 15:57:22, Andi Kleen wrote: > Jan Kara <jack@xxxxxxx> writes: > > ext4_io_end_t *cur_aio_dio; > > + > > + /* > > + * Transactions that contain inode's metadata needed to complete > > + * fsync and fdatasync, respectively. > > + */ > > + atomic_t i_sync_tid; > > + atomic_t i_datasync_tid; > > This might be a stupid question, but the atomic implies you don't hold > any kind of reference to the transaction. So what prevents these IDs > from wrapping while in there? Given it would be probably take a long > time today, but might be not fully future proof to very fast future IO > devices. Yes, IDs can wrap. But journalling layer actually compares them so that wrapping does not matter unless you manage to do 2^31 transactions inbetween. So we are still a few orders of magnitude safe with current hw. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
