Re: <DOT>foo gets NFSv4 HIDDEN attribute by default by nfsd? Re: How to set the NFSv4 "HIDDEN" attribute on Linux?

[Chuck Lever <chuck.lever@oracle.com>]

On Sat, Nov 25, 2023 at 09:52:36AM -0500, Jeff Layton wrote:
> On Fri, 2023-11-24 at 12:43 -0500, Chuck Lever wrote:
> > On Thu, Nov 23, 2023 at 11:24:10PM +0100, Cedric Blancher wrote:
> > > Also, it is legal for a nfsd to give the DOT files (/.foo) the HIDDEN
> > > attribute by default? Right now on Windows they show up because NFSv4
> > > HIDDEN is not set, and it is annoying.
> > 
> > I suppose an NFS server could do this, but I'm not aware of any
> > other multi-protocol file server (eg, Oracle ZFS or NetApp) that
> > does.
> > 
> > Dot-files are obscured on POSIX systems by the NFS clients and their
> > user space (ls and graphical file navigators). I don't see why the
> > Windows NFS client can't be similarly architected. Or perhaps it
> > could fabricate the HIDDEN attribute for such files itself.
> 
> Question. GETATTR operates on filehandles, which are roughly analogous
> to inode with Linux nfsd:
> 
> $ touch visible
> $ ln visible .hidden
> 
> Is the resulting inode and filehandle now considered HIDDEN or not?
> 
> These kinds of issues are endemic when trying to map MS Windows concepts
> onto Linux (and vice-versa).

The semantics of dot-files and HIDDEN are not the same, truly.

Interestingly, Samba supports a "hide dot files" option:

  https://www.samba.org/samba/docs/using_samba/ch08.html

It also implements a regular expression mechanism for faking HIDDEN
based on filename matching. Apparently the Samba folks don't believe
the difference between a HIDDEN inode and an obscured  directory
entry is important. Or perhaps they do this to work around missing
local file system support for storing the HIDDEN attribute.

I think I still prefer implementing an actual file attribute to
store the setting per-file. HIDDEN seems like a characteristic that
should be controlled by the file owner or the (client) application
that is managing a view of the file's parent directory, and not by a
server's administrator.


-- 
Chuck Lever