On Wed 20 Mar 2019 10:16:10 AM CET, Kevin Wolf wrote: >> Oh, I see. Let's use a shorter chain for simplicity: >> >> A <- B <- C <- D <- E > > Written from right to left, i.e. E being the base and A the top layer? > We usually write things the other write round, I hope this doesn't get > too confusing later.
Oh my... yes, of course you're right, I should have written it the other way around: E <- D <- C <- B <- A >> 1) If we stream first from E to C we add a filter F: >> >> A <- B <- F <- C <- D <- E ( which should have been written E <- D <- C <- F <- B <- A ) >> Now we can't stream from C to A because F is on the way, and the F-C >> link is frozen. > > Why is a frozen link a problem? The streaming operation isn't going to > change this link, it just copies data from the subchain (including F > and C) to A. This is not something that a frozen link should prevent. Not the operation itself, but the first thing that block-stream does is freeze the chain from top (A) to base (C), so this would fail if there's already a frozen link on the way (C <- F on this case?). > So it seems frozen links allow the wrong case, but block the correct > one? :-( Yes, we probably need to rethink this scenario a bit. Berto
