On Wed, Jul 20, 2011 at 08:07:58PM -0400, J. Bruce Fields wrote: > On Fri, Jun 10, 2011 at 09:48:59AM -0400, J. Bruce Fields wrote: > > On Fri, Jun 10, 2011 at 09:56:49AM +0200, Volker Lendecke wrote: > > > Without having looked too deeply, just let me point out that > > > Samba here has a plain flaw. Early Linux Kernel versions > > > that we programmed against did not properly support read > > > only leases, so we did not implement that initially. If I > > > remember correctly we never got around to finally do it once > > > it became available. Eventually we will probably, as read > > > only leases are a pretty important feature to present to > > > CIFS clients. > > > > Thanks, I didn't know that. (Or I did, and I forgot.) > > > > When you *do* implement that, is there any chance you'd have this need > > to be able to downgrade to a read lease in the case of a conflict? > > So it's a question about the protocols samba implements: > > - Do they allow an atomic downgrade from an exclusive to a > shared oplock? (Or to a level 2 oplock, or whatever the right > term is). Yes. Exclusive can go to level 2 - in fact that's the default downgrade we do (unless an smb.conf option explicity denies it). > - If so, can that happen as a response to a conflicting open? > (So, if you're holding an exclusive oplock, and a conflicting > open comes in, can the server-to-client break message say "now > you're getting a shared oplock instead"? Or is the client > left without any oplock until it requests a new one?) Yes, this can happen. In SMB, we only break to no lease when a write request comes in on a exclusive or level2 oplock (read-lease) handle. Jeremy. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
