[PATCH] smbd: Fix snapshot query on shares with DFS enabled

[Jeremy Allison]

On Wed, Aug 17, 2016 at 01:55:04PM -0700, Jeremy Allison wrote:
> On Wed, Aug 17, 2016 at 11:33:21PM +0300, Uri Simchoni wrote:
> > On 08/17/2016 11:23 PM, Jeremy Allison wrote:
> > > On Wed, Aug 17, 2016 at 01:19:11PM -0700, Jeremy Allison wrote:
> > >>
> > >> Ah ok - that's the missing piece ! I'd prefer the /server/share/path/to/file/@GMT-xxx
> > >> approach as that prevents us having to mess understand when we have
> > >> a DFS vs. regular path.
> > >>
> > >> I'm assuming the above also works with Windows ? I'm having
> > >> trouble on my W2K12R2 box getting @GMT paths to work with SMB1.
> > > 
> > > Ah ! Yes it does. Just found in MS-SMB:
> > > 
> > > -----------------------------------------------------------------
> > > 2.2.1.1.1 Pathname Extensions
> > > 
> > > Pathnames are allowed to contain a previous version token (or @GMT token), as a directory
> > > element in a path. A previous version token indicates that the pathname is a request to access the
> > > previous version (or shadow copy) of the file or directory at a particular point in time. This feature
> > > is available on any path-based operation (for example, SMB_COM_NT_CREATE_ANDX). A pathname
> > > MUST NOT contain more than one previous version token.
> > > For example, requesting a previous version of the file \\server\mydocs\reviews\feb01.doc at
> > > 2:44:00 P.M. on March30, 2001 UTC is specified in the following format:
> > > \\server\mydocs\reviews\@GMT-2001.03.30-14.44.00\feb01.doc
> > > The same technique can be used to build a path that represents a previous version of a directory as
> > > opposed to a file.
> > > For example, requesting a previous version of the directory \\server\mydocs\reviews at 2:44:00 PM
> > > on 3/30/01 UTC can be specified in either of the following formats:
> > > A token appearing as an intermediate path component:
> > > 
> > > \\server\mydocs\@GMT-2001.03.30-14.44.00\reviews
> > > 
> > > A token appearing as a final path component:
> > > 
> > > \\server\mydocs\reviews\@GMT-2001.03.30-14.44.00
> > > -----------------------------------------------------------------
> > > 
> > *as a directory element* ...
> 
> The last component *Is* a directory element :-). The long
> and the short of it is, does this work against Windows ?
> 
> Right now I can't get SMB1 @GMT- components to work against
> a Win2K12 server. An SMB1 cli_shadow_copy_data() call returns an empty
> list, but an SMB2 cli_shadow_copy_data() (with my patch)
> can see them.
> 
> Any idea what I'm missing ?

Ah, this might be a clue...

http://www.snia.org/sites/default/orig/sdc_archives/2008_presentations/thursday/DavidKruse_BeyondCIFS.pdf

 SMB_FLAGS2_REPARSE_PATH hints that @GMT is present