On Fri, Jun 01, 2018 at 06:42:37AM -0400, Jeff Layton wrote: > Thanks for having a look. Hmm...you're right. > > nn->nfsd4_lease = 90; /* default lease time */ > nn->nfsd4_grace = 90; > > nit: We should probably add a #define'd constant for that at some > point...but, might this be problematic? > > In the pessimal case, you might renew your lease just before the server > crashes. It then comes back up quickly and starts the grace period. By > the time the client contacts the server again the grace period is almost > over and you may have very little time to actually do any reclaim. > > ISTR that when we were working on the server at PD we had determined > that we needed around 2 grace periods + a small fudge factor. I don't > recall the details of how we determined it though. OK, I'd be interested in any of that. If we decide we need a larger grace/lease ratio, we may want to adjust default lease down at same time to avoid increasing grace period, as that's always an annoyance. > Even worse: > > $ cat /proc/sys/fs/lease-break-time > 45 > > Maybe we should be basing the v4 lease time on the lease-break-time > value? It seems like we ought to revoke delegations after two lease > periods rather than after half of one. No, we ignore lease-break-time on delegations. See the comment in fs/nfsd/nfs4state.c:nfsd_break_deleg_cb(): /* * We don't want the locks code to timeout the lease for us; * we'll remove it ourself if a delegation isn't returned * in time: */ fl->fl_break_time = 0; --b. -- 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
