On Wed, Oct 07, 2020 at 07:34:27AM -0700, Frank Filz wrote: > > -----Original Message----- From: J. Bruce Fields > > [mailto:bfields@xxxxxxxxxxxx] Maybe I overlooked the obvious: if > > Chrome holds a lock on that file when you suspend, and if you stay > > in suspend for longer than the NFSv4 lease time (default 90 > > seconds), then the client will lose its lease, hence any file locks. > > I think these days the client then returns EIO on any further IO to > > that file descriptor. > > > > Maybe there's some way to turn off that locking as a workaround. > > > > The simplest thing we can do to help might be implementing > > "courteous server" behavior: instead of automatically removing locks > > after a client's lease expires, it can wait until there's an actual > > lock conflict. That might be enough for your case. > > > > There's been a little planning done and it's not a big project, but > > I don't think it's actually at the top of anyone's todo list right > > now, so I'm not sure when that will get done. > > I've had courtesy locks on my back burner for Ganesha though I hadn't > thought about that there might actually be an important practical > issue. Does any other server implement them? If we suggest this as a > solution to the Chrome suspend issue, it might be good to assure that > the major server vendors implement this. > > There is a problem with the courtesy locks for this solution though... > The clientid is still going to be expired, and the locks are > associated with the clientid, so unless we allow courtesy > re-instatement of expired clientids, courtesy locks don't actually > solve the problem... The server's not required to expire the clientid when the lease expires. A server that chooses to be "courteous" can let it hang around. As a first implementation our server would probably wait until there's a lock conflict, then destroy all the client's state. But we could also choose to revoke only those locks we have to. The client uses TEST_STATEID, I think, to sort out what's happened in that case. I believe the Linux client implements all of this. I'm not sure about the status of other servers. --b.
