Hi, Thanks Mike and Josh for the answer, I see how it works now. Using a pipe seems like a good fit for me. One more question: When I have async read pending, I would have expected rbd_flush and/or rbd_close to wait for them to finish but they dont. Is there a way to wait for all operation to be complete ? Because if I shutdown everything before they are, the application hangs ... Cheers, Sylvain -- 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