On Mon, 28 Jul 2014, Sage Weil wrote: > On Sun, 27 Jul 2014, John Spray wrote: > > I think that for the calls where we check the epoch and then > > conditionally call wait_for_map with the context, we have to change > > them to do the wait_for_map call first and check the boolean response. > > Otherwise, if the map we have is updated between the read of the epoch > > and the call to wait_for_map, it could already be ready and never call > > back our context. > > > > My version is here (on top a rebase of wip-objecter to master on branch > > wip-objecter-rebase): > > https://github.com/ceph/ceph/commit/3cd82464ed6f13ec5b44da303849061648b9e3a1 > > Okay, I finally got around to looking at this again, and it looks like we > managed to collide on a few things. The wip-objecter-rebase branch is > missing the change in my series, specifically the old commit > > fa8d2d581b3da0fc5176a674623738cd555a3766 > > is replaced with > > 7cb3cf98b09685ebd48451878ded3cbc212e0a12 > > in the (rebased) wip-objecter. Also, the missing } was squashed into > > e596ad8e67719f7fb8e96b579c34a438f51c319f > > Anyway, I rebased and resolved conflicts and pushed a new > wip-objecter-rebased which looks like it has the right diff between the > old and new versions. > > Take a look? The main change is that the set data pool virtual xattrs do > objecter->wait_for_latest_osdmap() and the flawed MDS::request_osdmap() > helper is now gone. ...and I pushed a couple more patches. One fixes the wait_for_map callers so that they don't leak the completion when we already have the map. The second applies the _IO_ naming thing to completions that have to retake the mds_lock. But that makes me realize that a handful of the MDLog::submit_entry() callers are passing in completions that take the lock, but there are a zillion other callers that aren't. I wonder if a safer approach is to make a subclass of Context called RelockingContext, which takes an mds_lock * in the ctor, and then make all of the other completions subclasses of that. That way we can use type checking to ensure that all Context's passed to MDLog::submit_entry() (or other places that make sense) are of the right type. Hopefully there aren't any classes that are used in both and locking and non-locking context... Alternatively, we could make a LockingFinisher class that takes the specified lock (mds_lock) before calling each Context. That might be simpler? sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
