-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Mon, 21 May 2012 21:13:21 +0000 Obaid Farooqi <[email protected]> wrote:
> Hi Jeff: > Please let me know if my response answered your question. > > Regards, > Obaid Farooqi > Escalation Engineer | Microsoft > > Exceeding your expectations is my highest priority. If you would like to > provide feedback on your case you may contact my manager at nkang at > Microsoft dot com > > > -----Original Message----- > From: Obaid Farooqi > Sent: Tuesday, May 15, 2012 10:44 AM > To: 'Jeff Layton' > Cc: '[email protected]'; '[email protected]'; '[email protected]'; > '[email protected]'; MSSolve Case Email > Subject: RE:[REG:112042860618701] SMB1 -- proper client behavior when it does > not hold an oplock > > Hi Jeff: > The SMB protocols do not have any specific requirement as to how much or how > little caching is allowed on the client side. An implementation could very > well "choose to batch writes for a short period of time" even in the absence > of an oplock/lease. However, then there are no data consistency guarantees > between multiple readers and writers. Oplocks/leases provide a mechanism for > implementers to guarantee better data consistency. > > Windows in general does not do caching in the absence of oplock/lease. The > specific conditions in which caching without oplock/lease may happen is > implementation detail, not protocol. > > Please let me know if it answers your question. > > Regards, > Obaid Farooqi > Escalation Engineer | Microsoft > > Exceeding your expectations is my highest priority. If you would like to > provide feedback on your case you may contact my manager at nkang at > Microsoft dot com > > -----Original Message----- > From: Obaid Farooqi > Sent: Monday, April 30, 2012 10:14 AM > To: 'Jeff Layton' > Cc: [email protected]; [email protected]; [email protected]; > [email protected] > Subject: RE:[REG:112042860618701] SMB1 -- proper client behavior when it does > not hold an oplock > > Hi Jeff: > I'll help you with this issue and will be in touch as soon as I have an > answer. > > Regards, > Obaid Farooqi > Escalation Engineer | Microsoft > > Exceeding your expectations is my highest priority. If you would like to > provide feedback on your case you may contact my manager at nkang at > Microsoft dot com > > > -----Original Message----- > From: Jeff Layton [mailto:[email protected]] On Behalf Of Jeff Layton > Sent: Friday, April 27, 2012 1:34 PM > To: [email protected]; [email protected]; Interoperability > Documentation Help > Cc: [email protected]; [email protected] > Subject: SMB1 -- proper client behavior when it does not hold an oplock > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Sorry for the duplicate emails, but I sent this to the wrong dochelp address > before. Let me try again... > > Hi Dochelp! > > I'm hoping you can help clarify some points about proper SMB1 (and maybe > SMB2?) client behavior when it does not hold an oplock (at least one that > allows write caching). > > My understanding has always been that when a client does not have an oplock > that allows write caching, then it should not cache any writes > - -- full stop. If an application does a write then the kernel should not > return until it has been sent to the server and the reply has come back. That > behavior is at least suggested in MS-CIFS, though it does not come out and > state that explicitly. > > OTOH, Steve French suggested that that's not required by the protocol and > that clients are allowed to buffer up writes "briefly" in order to allow the > redirector to batch up small writes into a single request as long as it > flushes them out in a timely fashion. That seems a little crazy to me, but I > guess it's not the craziest thing in SMB1 if so... > > So I guess my questions are: > > 1) What does the protocol actually mandate? Are you allowed to briefly buffer > up writes before returning to an application when the client holds no oplock? > > 2) What does Windows actually do in this regard? If you are not allowed to do > that by the protocol, then does it follow this strictly or does it do as > Steve suggests and batch up small writes until it can fill a write request? > > Thanks for any info you can provide! Sorry, I thought I had replied. Thanks for the answer, it was very helpful! - -- Jeff Layton <[email protected]> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIcBAEBAgAGBQJPu8mBAAoJEAAOaEEZVoIVZH0QAIO+LAu6zr2W1W+FXXD2cmgj pPZPd0dMCX44rmk2UciqwAOJszdmq3VeLKrP3HtZKjxMu7xo6buYgYfNpD1dNgy3 ie9XK0Z8xOCkR1EvXNlVBcWaTy/hso2J4agpt2aKX+iY4Z8IA6D+3YhMhxAXBUsR hU+mdfOvFZ3HQEGI7nFJCT45HXR6TIx0HntO/qslbf0NFYMJrPkp7iP33BCPKTOO yr8UKQXRINGZk1wa+dlMjsihoNhDsR5SXLa73oIUbFs3vT2FE8kIBq56pJ0HwMTa JW9PXkaztBXFLVnAMumscn6P5wxOVtZdljwGWEYleEmjNSW0RgJ4vaQXkYP5cSkN y2mspEuQCadyTxGxCg8KfXWH9IOTUM31GJtVKUh4tzwpy3qTbG4wdgow7Iktzuzc nTKFEinYxGYIo8rfJSItuBnzNZyld1XW7JrtIhXPEb1QLqvt0fEgSk52BhuRiWnB qrV6qOb8Gogh6roaVGMCaltobzD4Y5xzosEwM9KGi5Rxc68y9xA4Yr/ujRvrVLi1 I0JCm82WwKCarpTQnoIUryWEjvsuS3NhCRSuXz+ICY4Yso9uuOOexHoC7cbTrTOm SaP4lUBwE/8zAdgYA/qlnsastZ+LGX+DcyBzgmIdmYzlJJr8b5WcxpVrNp+Fq0p7 npmQWOG8Q0ARdF+Uu5Yq =cMIz -----END PGP SIGNATURE----- _______________________________________________ cifs-protocol mailing list [email protected] https://lists.samba.org/mailman/listinfo/cifs-protocol
