Does the CreateDisposition flag of a client depend on Server's response ?

[varun mittal]

I observe the same behavior with my Win10 client and Samba server with
streams_xattr.

The /COPY:DATX didn't change the behavior for the directory, but /DCOPY:X
does as I had
mentioned in my earlier comments.
And not sure why, but only /DCOPY:X does, if I specify any other flag like
/DCOPY:DAX, it doesn't :)


On Mon, Feb 6, 2023 at 11:24 PM Tom Talpey <tom at talpey.com> wrote:

> Aha - ok, if Windows-to-Windows is broken, it's in robocopy.
> Interestingly, I can't repro this from my Win11 system to
> a Samba server with streams_xattr loaded.
>
> Yes, I'm aware it's the directory create that fails.
>
> Maybe one other thing to test. What if you add the "X" copyflag,
> which turns off copying streams? Perhaps your robocopy.exe will
> ignore the filesystem stream attribute and use FILE_OPEN like usual.
> It's purely an academic exercise though.
>
> robocopy C:\Users\mittal\Downloads Y:\Shared\Folder1\Subfolder
> <file-name> /COPY:DATX /R:1 /W:10
>
>
>
> On 2/5/2023 11:44 AM, varun mittal wrote:
> > Hi Tom
> >
> > I did test it with Windows share too and the behavior was the same.
> > But please note, the FILE_OPEN_IF I am chasing is for the Directory
> > and not the files.
> > In my case, the source directory doesn't have any named data stream.
> > The files in the source directory also didn't have any ADS. These files
> were
> > generated locally.
> >
> > On Sat, Feb 4, 2023 at 7:38 PM Tom Talpey <tom at talpey.com
> > <mailto:tom at talpey.com>> wrote:
> >
> >     This is worth figuring out.
> >
> >     Because it's a file in your Downloads folder, it was probably
> >     created by a browser. This means it has an additional stream
> >     which indicates it's from the internet. Defender and other
> >     tools use the presence of that stream to throw the "Do you
> >     really want to open this file?" dialogs.
> >
> >     When you copy the file to a non-stream filesystem, that stream
> >     is obviously lost, in which case robocopy is not going to do
> >     anything special. But when copying to a filesystem that does,
> >     it will take a different path, copying everything. Or maybe it's
> >     the fact that it's in the Downloads folder, and robocopy is
> >     being clever. Or just a bug in the Win10 robocopy you mentioned
> >     you're using.
> >
> >     Would you happen to have a Windows system with an NTFS share
> >     that you could robocopy the same file to, and grab a trace?
> >
> >     It would give us the breadcrumbs to figure out what's missing.
> >     Maybe there's some other volume or filesystem attribute that's
> >     missing, and confusing robocopy.
> >
> >     Tom.
> >
> >     On 2/4/2023 3:17 AM, varun mittal wrote:
> >      > Nothing fancy, simple copy command:
> >      > robocopy C:\Users\mittal\Downloads Y:\Shared\Folder1\Subfolder
> >      > <file-name> /COPY:DAT /R:1 /W:10
> >      >
> >      > On Sat, Feb 4, 2023, 8:05 AM Tom Talpey <tom at talpey.com
> >     <mailto:tom at talpey.com>
> >      > <mailto:tom at talpey.com <mailto:tom at talpey.com>>> wrote:
> >      >
> >      >     On 2/3/2023 12:50 PM, Jeremy Allison via samba-technical
> wrote:
> >      >      > On Fri, Feb 03, 2023 at 08:51:57PM +0530, varun mittal
> wrote:
> >      >      >>   I was able to narrow it down to the "Named Streams" bit
> in
> >      >      >>   "FileFSAttributeInformation" response.
> >      >      >>   When this value is toggled from 0 to 1, as is
> advertised by
> >      >      >>   `streams_xattr` VFS module, Robocopy
> >      >      >>   switched from FILE_OPEN to FILE_OPEN_IF.
> >      >      >>   Thanks
> >      >      >
> >      >      > Thanks for tracking that down. What strange behavior.
> >      >      > I can't see why having a stream would make the open
> >      >      > change to optionally creating the file, but it's good
> >      >      > info to know. Thanks for posting the follow-up to
> >      >      > the list !
> >      >
> >      >     It's not the presence af a stream, it's that the fileystem
> >     supports
> >      >     named streams. It's getting that from a
> >     FileFsAttributeInformation
> >      >     on the root directory.
> >      >
> >      >     Robocopy has a very broad range of OS- and FS-dependent
> behaviors
> >      >     and optimizations. I bet there's some combination of its
> 1000-odd
> >      >     commandline options that can change this.
> >      >
> >      >     Varun, what exact robocopy command are you seeing this from?
> >      >
> >      >     Tom.
> >      >
> >
>