On Fri, Mar 27, 2015 at 11:41:35AM +0100, Christoph Hellwig wrote: > FYI, I small update on tracking down the recall issue: this seems to > be very much something in the callback channel on the server. When tracing > the client all the recalls it gets they are handled fine, but we do get > error back in the layout recall ->done handler, which most of the time > but not always are local Linux errnos and not nfs error numbers, indicating > something went wrong, probably in the RPC code. I think I've tracked down the major issue here (I think there are some more hidding in the backchannel error handling as well): - the Linux NFS server completely ignores the limits the client specifies for the backchannel in CREATE_SESSION, most importantly the ca_maxrequests value. Thus it will happily send lots of callback requests that can overflow the clients callback slot table. - even worse the Linux client has a callback slot table with just a single entry, so this is pretty easy to trigger. I can try to dive into this, but it might make sense if someone more familar with the sessions implementation could look into this issue. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
