miscellaneous server patches

[J. Bruce Fields]

On Fri, May 04, 2007 at 11:43:13AM +1000, Neil Brown wrote:
> How important is it to get the grace periods synchronised anyway?
> 
> The clients don't really know when it is going to end - they just know
> how long it is and at some point they find out that it has started.
> Then they just slam out lock reclaim requests and hope they get them
> all in in time.

Also, a more subtle requirement: we need to ensure that before any (nlm
or nfsv4) client gets a lock, that we have information in stable storage
sufficient to prevent any NFSv4 client which failed to reclaim state
during this grace period from being allowed to reclaim state later.

(There's a worry about conflicts with reclaims which are still be out
there and may not show up until the *next* reboot, thanks to a client
that lost its network connection and doesn't realize it missed the first
grace period....)

But that requirement can be met by a simpler mechanism than what we're
using now.  So I agree that there's room for improvement.  I'll try
setting aside a day to take a look at this next week.

> Related topic:  I think it would be good to move all the purely
> server-side parts of lockd into fs/nfsd.  This would include all the
> grace handling, the list of open files, and a lot of code for handling
> incoming lock requests.

Hm, OK, I'll keep that in mind.

--b.