cp -p fails to preserve time

[Jeremy Allison]

On Tue, Jul 31, 2018 at 08:39:07PM +0000, Rungta, Vandana wrote:
> Windows behaves the same way as Samba.  If mounted from a Linux client with vers=3.0 cp -p does NOT preserve time, if mounted with vers=1.0 cp -p preserves time.

Ah, then we're doing the right thing for SMB2, and the client
needs to change in order to preserve the time over SMB2.

Remember, "the right thing for SMB2" is defined as "what
Windows does". For SMB1 the client is using UNIX extensions,
which allow us to change the protocol semantics. We don't
do that for SMB2, so the client will have to adapt in order
to try and get the desired semantics.

Jeremy.