On Fri, 2021-09-24 at 05:46 +0200, Ralph Boehme wrote: > Am 24.09.21 um 05:35 schrieb Trond Myklebust: > > Not if you set the "kernel oplocks" parameter in the smb.conf file. > > We > > just added support for this in the Linux 5.14 kernel NFSv4 client. > > > > Now that said, "kernel oplocks" will currently only support basic > > level > > I oplocks, and cannot support level II or leases. According to the > > smb.conf manpage, this is due to some incompleteness in the current > > VFS > > lease implementation. > > > > I'd love to get some more info from the Samba team about what is > > missing from the kernel lease implementation that prevents us from > > implementing these more advanced oplock/lease features. From the > > description in Microsoft's docs, I'm pretty sure that NFSv4 > > delegations > > should be able to provide all the guarantees that are required. > > leases can be shared among file handles. When someone requests a > lease > he passes a cookie. Then when he opens the same file with the same > cookie the lease is not broken. Right, but that is easily solved in user space by having the cookie act as a key that references the file descriptor that holds the lease. This is how we typically implement NFSv4 delegations as well. > > Maybe others can comment on the level II oplock problem. Afaik this > was > more a lack of testing. That would really be a bit of a shame, since the use of leases on top of networked or clustered filesystems could help speed up state management operations by avoiding the need for a separate distributed lock manager. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
