Am 08.04.2015 um 21:22 schrieb Stefan Hajnoczi: > On Wed, Apr 8, 2015 at 6:08 PM, ronnie sahlberg > <ronniesahlb...@gmail.com> wrote: >> The nice part with the current patch of Peter is that qemu and >> libiscsi can be upgraded/downgraded independently. > That's fine for avoiding hassles for existing apps, like QEMU, and I'm > happy to merge the patch. > > For the library's API design it would be return the timeout so that > new applications can avoid polling, but that's just a suggestion.
You are right. Paolo also brought up this idea, but as Ronnie said the idea was not to bump the API version. The whole async reconnect stuff works without a change in the client. But polling every 250ms is magnitutes better than having a hung Qemu :-) If you feel 250ms is too often we could also go to 1000ms. The timeout we are talking about is in the order of 1-30 seconds. It only happens when a reconnect is initiated either bei Qemu (due to NOP timeout) or libiscsi (protocol, socket error etc.) and the first reconnect try is not successful. Another idea I had was to encode the timeout in the return value of iscsi_which_events. This would work with all Qemu versions, but I do not know how poll reacts if it gets unknown events passed. So all users other than Qemu that pass the result of iscsi_which_events directly to poll would need to mask the result. Thats not a problem for the tools provided with libiscsi, but I do not know how much other real users except Qemu are out there? Peter
