vfs_auto

[Andrew Bartlett]

G'Day,

Seeing what looks like a really interesting module in vfs_snap, and
thinking about the trouble folks running btrfs and zfs have with Samba,
having to run specific modules, I wondered if we should have a new,
meta-module: vfs_auto

That is:  We can detect almost as well as the system administrator what
VFS modules they need for specific back-end file systems, and we hide so
much of our correctness code behind optional, off by default modules.

This is all OK if our users are NAS vendors and others who control the
end environment, and so know to turn on modules, but what about everyone
else?  Why shouldn't Samba 'just work' with a bare minimum of
configuration?  Why should good features like streams support, snapshot
creation, copy_chunk or full NT ACLs be hidden inside otherwise unknown
modules?

We do this already for POSIX ACLs, with vfs_default calling into the
'right' ACL code as detected at build time, but could we do this in
general, including for other features?

We also do this already for LDB, with samba_dsdb being the meta-module
loading the correct other modules. 

It would also allow us to handle better what is done in loadparm for the
AD DC, as the default VFS modules could vary based on server role. 

We could handle the upgrade problem by leaving the default to be "", but
to encourage folks to set it to "auto" in documentation and examples.
Folks that want strict control and no changes could still specify an
exact set of modules.

What do others think?  Does someone want to have a go at implementing
this?

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett                       http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba