Better interop for NFS/SMB file share mode/reservation

Ralph Böhme slow at
Wed Mar 6 21:25:18 UTC 2019

Jeremy Allison wrote:
> 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:
>>> 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:
>> 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.

Just to be precise: SMB2.1+ has R, RH, RW and RWH 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.

That'a a propertly of leases in general, not just H-leases. The client provides a lease key which is a GUID with each lease request

> Here are the semantics:
> 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 ?

Yes, that would be ideal.


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