> >You need to understand how a block_rsv works, > >both block_rsv and space_info are a kind of _container_: > > Introducing metadata reseravtion contexts has two major >advantages. > First, it makes metadata reservation more traceable. > Second, it can reclaim freed space and re-add them to the >itself after transaction committed. > > >here is a basic model: > > +--+--->size +--+--->size +--- >-----------+ > | | | | | > | > | | | | | > | > +--+--->reserved +--+--->reserved +--- >-----------+-->may_used > | | | | | > | > | | | | | > | > | | | | | > | > +--+ +--+ +--- >-----------+ > block_rsv + block_rsv + ... = >space_info(flag=4) > A B | > | > +--> reserved >meta bytes > > >Hope that this helps. > >thanks, >liubo I'm afraid it's a bit late to say thanks, LiuBo. I saw your June 11 replay yesterday, I have not touched my mail account for nearly ten days since my original post, I thought it would have been burried by time after I kept watching someone's replay for 2, 3 days and failed to get one. your illustration is usefull for me, I will re-browse some rsv code with it. thank you very much, WeiFeng Liu -- 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
