[linux-cifs-client] Re: Re: Re: Re: Timestamps not preserved onCIFS mount

[Jeff Layton]

On Mon, 10 Mar 2008 15:49:01 -0400
"Eric B." <ebenze at hotmail.com> wrote:

> "Jeff Layton" <jlayton at redhat.com> wrote in message 
> news:20080310075757.77c135cf at tleilax.poochiereds.net...
> 
> > > >just some additional thoughts on your problem i forgot
> > > >to mention.
> > > >When the samba server on your storage device is not running
> > > >the cifs "unix extensions", the windows like smb functions
> > > >are used - so you can probably been hit by the currently
> > > >failing implementation, too.
> > > >
> > > >Btw - many NAS devices (even still sold today) are running
> > > >samba-2.x.x. I've been told in many places, that users had problems
> > > >when using cifs vfs - but smbfs was working (for their limited needs).
> > >
> > > Thanks for the info.  I'm actually trying cifs b/c of problems I am
> > > encountering with smbfs; the timestamps work properly, but I keep 
> > > getting
> > > error/warning msgs regarding inability to set permissions and/or 
> > > ownership
> > > of the files.  For example:
> > > # cp -a /home/eric/deploy /mount/smbfs
> > > cp: failed to preserve ownership for `./deploy/checksum.sh~': Permission
> > > denied
> > > cp: failed to preserve ownership for `./deploy/checksum.sh': Operation 
> > > not
> > > permitted
> > > cp: failed to preserve ownership for `./deploy/deploy-dev': Operation 
> > > not
> > > permitted
> > >
> > >
> > > I also get the same error msgs if I try rsync instead:
> > > # rsync -a /home/eric/deploy
> > > rsync: chown "/mount/bashful/cifs/deploy" failed: Operation not 
> > > permitted
> > > (1)
> > > rsync: chown "/mount/bashful/cifs/deploy/.checksum.sh.TDQedW" failed:
> > > Operation not permitted (1)
> > > rsync: chown "/mount/bashful/cifs/deploy/.checksum.sh~.KZ1wck" failed:
> > > Permission denied (13)
> > > rsync: chown "/mount/bashful/cifs/deploy/.deploy-dev.KweNfI" failed:
> > > Operation not permitted (1)
> > >
> > >
> > > I figured that those probs might be avoided with cifs, and indeed they 
> > > are,
> > > but am running into the timestamp issue.  If I could resolve the 
> > > ownership /
> > > chown problem in smbfs, I'd be happy to stick with that as well.
> > >
> > > Any ideas where I might be able to find help about that?  Maybe a 
> > > newsgroup
> > > or mailing list that would be good for smb issues like this?  I was 
> > > hoping
> > > to find a resolution for the cifs problem here, but that proves to be 
> > > too
> > > difficult, I'll revert to looking for a smbfs soln instead.
> > >
> >
> > I'd suggest first testing a newer kernel. That one is pretty ancient
> > by now. The RHEL4.6 kernel contains a much more updated CIFS version
> > and this may "just work" there. If it still doesn't work with that,
> > then I'd suggest testing the kernels on my RH people page:
> 
> Well, the machine that has been causing me all this grief is a production 
> server, so unfortunately I can't just update the kernel and reboot it 
> without proper notice, planning, etc. without causing some significant 
> outages for some users.  However, I do have a spare machine that I installed 
> CentOS4.6 on and I figured I would run tests there instead.  I have done a 
> full yum update on the machine, so in theory, everything is up-to-date.   I 
> have even double checked that I had the latest kernel.
> 
> # uname -a
> Linux OMG3 2.6.9-67.0.4.ELsmp #1 SMP Sun Feb 3 07:08:57 EST 2008 i686 i686 
> i386 GNU/Linux
> 
> 
> I am still running into problems.
> 1) For some reason, mount with the fdqn of my nas does not work.  I have to 
> use the IP.  Is there a reason for this?  On 2.6.9-34, the fqdn works fine. 
> Yes - the name is properly resolved (I am able to ping the fqdn), and the 
> dns server is in my /etc/resolv.conf file.  If I try to mount the fqdn, I 
> get errors in my dmesg and /var/log/messages
> # mount -t cifs //bashful.domain.com/backups  /mount/bashful -o username
> kernel:  CIFS VFS: cifs_mount failed w/return code = -22
> 

...sounds like there may be a problem with resolving the domain name?
It might be interesting to see some cifsFYI output from this.

> The only way I was able to get the mount to work is to use the IP address. 
> Is this a "feature" of a later CIFS version?
> # mount -t cifs //192.168.1.10/backups  /mount/bashful -o username
> 

It shouldn't be. Do you also have the samba-client package installed?
If you don't then you don't have the mount.cifs program and it won't be
able to resolve the fqdn before mounting. As a quick check...

$ ls -l /sbin/mount.cifs


> 2) Once I managed to get the mount up and working, I am running into the 
> same problems I had with my samba share.  Although the timestamp is properly 
> set this time, I get the same errors setting ownership that I was getting 
> with the smbfs (but not getting in the previous cifs):
> 
> cp: failed to preserve ownership for `./install.log': Permission denied
> 

This is expected, presuming that you're mounting the share as an
unprivileged user. Samba will do the file operations on the share as
that user and won't allow you to change ownership of those files to
someone else.

If it did otherwise it would be a (huge) security problem, since an
unprivileged user could potentially chown files to someone else (even
root).

> 
> So although the timestamp now works, in the overall context of things, I am 
> no further ahead as cp -a and rsync -a are still dumping out tons of warning 
> msgs about ownership and permissions of files.  Am I missing an obvious 
> parameters to my mount command, or am I doomed to keep these warning/error 
> msgs?
> 

You're doomed unless you can figure out how to mount this share as a
privileged user, and I don't recommend that anyway since it would
probably be very unsafe.

> Is there anything that I can do about this?
> 

Not much. I recently converted my home backups to use amazon S3 with a
program called "duplicity". You could conceivably use something like
that here and simply write the archive files to the CIFS share instead:

http://duplicity.nongnu.org/

Cheers...
-- 
Jeff Layton <jlayton at redhat.com>