On Wed, 16 Feb 2011 19:22:25 +1100
Darren Williams <darren.w@xxxxxxxxxxxx> wrote:
> Hi All
>
> Robert and Jeff thanks for working on and fixing this, I can confirm
> that we now have;
> - Remote DFS mounts working, using
> - both sec=krb5 and sec=ntlm.
>
> I'm just looking for clarification on the following feature or bug:
>
> we have a SAMBA server, samba1, serving a DFS root as follows
>
> [dfs]
> path = /export/samba/dfs
> msdfs root = yes
>
> configured as:
>
> ls -l /export/samba/dfs
> total 8
> lrwxrwxrwx 1 root root 79 2010-03-10 07:53 home ->
> msdfs:samba1\dfshome,samba2\dfshome
>
> and SAMBA servers, samba1 and samba2 with shares:
>
> [dfshome]
> comment = DFS Linux Home Directories
> path = /export/home/1/%u
> create mask = 0700
> force create mode = 0700
> directory mask = 0700
> force directory mode = 0700
> read only = No
> browseable = No
> valid users = %U
> map acl inherit = yes
>
>
>
> If I cifs mount the DFS root using
> mount.cifs //samba1/dfs /tmp/dfs -o <options as required>
> then list the directory I get the following errors:
>
>
> root@atp-h5gcn1s:~# mount.cifs //samba1/dfs /tmp/dfs/ -o <options>
> Password:
> root@atp-h5gcn1s:~# ls -l /tmp/dfs/
> ls: cannot read symbolic link /tmp/dfs/home: Object is remote
> ls: cannot read symbolic link /tmp/dfs/test-home: Object is remote
> ls: cannot read symbolic link /tmp/dfs/projects: Object is remote
> total 8
> lrwxrwxrwx 1 root root 79 Mar 10 2010 home
> lrwxrwxrwx 1 root root 46 Mar 10 2010 projects
> lrwxrwxrwx 1 root root 79 Mar 25 2010 test-home
> root@atp-h5gcn1s:~# ls -l /tmp/dfs/home/
> ls: cannot access /tmp/dfs/home/: Not a directory
> root@atp-h5gcn1s:~# umount /tmp/dfs
>
> I then remount and access a file in 'home' directly, which then allows
> the directory listing to succeed.
>
> root@atp-h5gcn1s:~# mount.cifs //samba1/dfs /tmp/dfs/ -o
> user=dwilliams,dom=NICTA
> Password:
> root@atp-h5gcn1s:~# ls -l /tmp/dfs/home/.bashrc
> -rw-r--r-- 1 <user> <group> 2450 Jun 8 2008 /tmp/dfs/home/.bashrc
> root@atp-h5gcn1s:~# ls /tmp/dfs/
> home projects test-home
> root@atp-h5gcn1s:~# ls -l /tmp/dfs/home/
> -rw-r--r-- 1 <user> <group> 3078 Aug 17 2007 2007-08-17-P.....
> ....
>
> also access is OK if you mount 'home' directly via dfs
>
> root@atp-h5gcn1s:~# mount.cifs //samba1/dfs/home /tmp/dfs/ -o <options>
>
> I'm looking for clarification on what the correct operation should be
> since our Windows clients can access the root the traverse the directory
> tree without error, not that this is evidence for correct operation.
>
I believe that's a bug...
The way things like autofs, DFS referrals and NFS used to work is by
pretending these mountpoints are symlinks and then abusing the
->follow_link operation on them in the kernel. Not all operations on
that inode trigger the follow_link op however, so sometimes -EREMOTE
errors bubble up when they shouldn't. Either that or we just have some
straightforward bad handling of -EREMOTE errors in the readdir codepath
-- I'm not sure yet :)
What may be best is to open a bug at bugzilla.samba.org and we'll chase
it down when we get a chance. If you do that, please cc me on it. FWIW,
I opened this bug a while back which is probably related, but haven't
had time to work on it:
https://bugzilla.redhat.com/show_bug.cgi?id=616765
This may also be helped by the d_automount patches that dhowells did
recently and that are going into 2.6.38, but I haven't had time to look
yet.
--
Jeff Layton <jlayton@xxxxxxxxxx>
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