Patch to add support for advertising FULLSYNC to Mac OSX Clients

[Jeremy Allison]

On Fri, Apr 07, 2017 at 10:13:25PM +0200, Ralph Böhme wrote:
> On Fri, Apr 07, 2017 at 11:04:04AM -0700, Jeremy Allison wrote:
> > 
> > Doesn't this need to be SMB_VFS_FSYNC_SEND() and
> > the whole thing use the standard async callback
> > mechanisms ?
> > 
> > Looking at https://goo.gl/Lw5bdz it doesn't say we can't
> > return an intermediate response followed by a completed
> > response.
> 
> It says:
> 
>   In response, the server must first process the SMB2 FLUSH command in the usual
>   manner, and then must flush the data to stable storage (that is, flush the
>   physical disk’s track cache) before responding to the client.
>   
> So we must use the sync sync.

It says:

"In response, the server must first process the SMB2 FLUSH command in the usual manner"

which for us is to go async if it takes longer than our normal
return time. Can we check with Apple. This is ambiguous, as I can't
believe their client will fail this if a server goes async. I
very much doubt the client code is special-cased for this to
fail if a server goes async. They are just waiting for the
final response.

We should ask for a clarification to:

"flush the physical disk’s track cache) before making a final
response to the client".