Excerpts from Liu Bo's message of 2011-05-19 04:11:24 -0400: > Introduce a new concept "sub transaction", > the relation between transaction and sub transaction is > > transaction A ---> transid = x > sub trans a(1) ---> sub_transid = x+1 > sub trans a(2) ---> sub_transid = x+2 > ... ... > sub trans a(n-1) ---> sub_transid = x+n-1 > sub trans a(n) ---> sub_transid = x+n > transaction B ---> transid = x+n+1 > ... ... > > And the most important is > a) a trans handler's transid now gets value from sub transid instead of transid. > b) when a transaction commits, transid may not added by 1, but depend on the > biggest sub_transaction of the last neighbour transaction, > i.e. > B->transid = a(n)->transid + 1, > (B->transid - A->transid) >= 1 > c) we start a new sub transaction after a fsync. > > We also ship some 'trans->transid' to 'trans->transaction->transid' to > ensure btrfs works well and to get rid of WARNings. > > These are used for the new log code. This is exactly what I had in mind. I need to read it harder and make sure it interacts well with the directory logging code, but I love it. Thanks! -chris -- 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
