On Wed, Mar 06, 2019 at 03:31:08PM -0500, Jeff Layton wrote:
On Wed, 2019-03-06 at 10:11 -0500, J. Bruce Fields wrote:
> On Tue, Mar 05, 2019 at 04:47:48PM -0500, J. Bruce Fields wrote:
> > On Thu, Feb 14, 2019 at 04:06:52PM -0500, J. Bruce Fields wrote:
> > > After this:
> > >
> > >
https://marc.info/?l=linux-nfs&m=154966239918297&w=2
> > >
> > > delegations would no longer conflict with opens from the same tgid. So
> > > if your threads all run in the same process and you're willing to
manage
> > > conflicts among your own clients, that should still allow you to do
> > > multiple opens of the same file without giving up your lease/delegation.
> > >
> > > I'd be curious to know whether that works with Samba's design.
> >
> > Any idea whether that would work?
> >
> > (Easy? Impossible? Possible, but realistically the changes required to
> > Samba would be painful enough that it'd be unlikely to get done?)
>
> Volker reminds me off-list that he'd like to see Ganesha and Samba work
> out an API in userspace first before commiting to a user<->kernel API.
>
> Jeff, wasn't there some work (on Ceph maybe?) on a userspace delegation
> API? Is that close to what's needed?
>
Here's the C headers for that stuff:
https://github.com/ceph/ceph/blob/7ba6bece4187eda5d05a9b84211fe6ba8dd287b...
It's simple enough and works for us in ganesha, and I think we can
probably adapt it to samba without too much difficulty. The callback
doesn't seem like it'll do for a kernel API though -- you'd almost
certainly need to do something different there (signals? inotify?).
SMB3 leases have R/RW and Handle-based leases.
Handle leases allow multiple opens of the same pathname
that get different handles to share the lease, allowing
a client redirector to delay opens or closes locally
so long as it has a handle lease.
Here are the semantics:
https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/d8df...
I'm not sure a simple file-descriptor based API is
enough for us. Can he have a uuid or token based
API instead where the server can chose what fd's
to cover with a token ?