[PATCH 1/8] lockd: nfsd4: use same grace period for lockd and nfsd4

[Neil Brown]

On Wednesday June 20, bfields at fieldses.org wrote:
> 
> OK.  How about this?

Thanks.

> 
> Currently the lockd and nfsd enforce grace periods of different lengths.
> This may cause problems when we reboot a server with both v2/v3 and v4
> clients.  For example, if the lockd grace period is shorter (as is likely
> the case), then a v3 client might acquire a new lock that conflicts with a
> lock already held (but not yet reclaimed) by a v4 client.

And if a local application, or an SMB client takes a lock...  It feels
like we want the grace period to be managed at the VFS level, but I
guess that is a question for another day.

> -		grace_period = ((nlm_grace_period + nlm_timeout - 1)
> +		return ((nlm_grace_period + nlm_timeout - 1)
>  				/ nlm_timeout) * nlm_timeout * HZ;

 return roundup(nlm_grace_period, nlm_timeout) * HZ;

I've made that change.

For the rest:
  It is clearly an improvement, but it is still all rather clunky,
  isn't it ?
  lockd and nfsd4 calculate the endtime of the period independently,
  and have separate flags for recording whether we are currently in
  the grace period.
  Those, at least, could be in variables exported from lockd.
  nfsd needs to perform an action before the grace period is allowed
  to end, so maybe we need a 'register_notifier' interface so that
  when nfsd or lockd notice that the grace period is up, the notifiers
  get called, and nfsd does it's cleanup.

Anyway, that can be work for another day, and you say you have more
plans for that code, so that is good.

NeilBrown