[Sheepdog] [PATCH] Remove unregister_event from sd_xxx_handler()

[Christoph Hellwig]

On Tue, May 15, 2012 at 03:01:46PM +0800, Yunkai Zhang wrote:
> With a second thought on this patch:
> https://mail-attachment.googleusercontent.com/attachment/u/0/?ui=2&ik=4a47af2829&view=att&th=1374cd782bf1a84a&attid=0&disp=inline&safe=1&zw&saduie=AG9B_P_WkgHa4wEYljmyBoplbIV_&sadet=1337064897009&sads=1zqvBm3krrhYKhyRnQOuHJT3znY
> 
> I think your solution have changed too more things: a lot of
> function's prototype. But with my solution, they are not necessary. We
> should not introduce difficult solution just because it could let you
> not need to rebase them.

I don't think your patch actually helps fixing the join race - the
cluster information is still not updated before sending the join
response on the master.  That beein said I like your changes anyway,
as they resuce the latency of updating the cluster information for
all other cases.

Another thing I noticed:  I don't think it's actually nessecary to let
the cluster drivers call update_cluster_info and update_epoch_info
directly, it should be perfectly fine to call them from inside
sd_join_handler and sd_leave_handler, and thus keep the interface for
the cluster drivers simpler.  That also means the local driver gets
updated automatically, which was missing in your patch.