[linux-cifs-client] [patch] do not attempt to update /etc/mtab if it is symbolic link

[Jeff Layton]

On Tue, 28 Jul 2009 10:50:09 +0530
Suresh Jayaraman <sjayaraman at suse.de> wrote:

> Jeff Layton wrote:
> > On Sun, 26 Jul 2009 15:01:08 -0500
> > Shirish Pargaonkar <shirishpargaonkar at gmail.com> wrote:
> > 
> >> If /etc/mtab is a symbolic link to e.g. /proc/mounts, do not update it.
> >>
> >> This is a fix for a bug reported in 4675 on samba bugzilla
> 
> While trying to lookup whether linking /etc/mtab to /proc/mounts is a
> defined/expected behavior, I came across this:
> 
> To quote `mount' man page:
> 
> "When the proc filesystem is mounted (say at /proc), the files /etc/mtab
> and  /proc/mounts  have  very similar contents. The former has somewhat
> more information, such as the mount options used, but is not
> necessarily  up-to-date  (cf.  the  -n option below). It is possible to
> replace /etc/mtab by a symbolic link to /proc/mounts, and especially
> when you have  very large numbers of mounts things will be much faster
> with that symlink, but some information is lost that way, and in
> particular working  with the loop device will be less convenient, and
> using the "user" option will fail."
> 
> So, wondering whether this has anything to do with the failure reported
> on Samba bugzilla 5118 ("user" fstab option vs "user" mount.cifs option)
> as the case was "user" option is expected to work (note: both of them
> reported on Debian which apparently links fstab to /proc/mounts)
> 
> I have not looked at the code, so I might be wrong..
> 
> > Looks good to me.
> > 
> > Acked-by: Jeff Layton <jlayton at redhat.com>
> 
> Thanks,
> 
> -- 
> Suresh Jayaraman

I don't think that's the case. I'm not sure why it wasn't working for
the reporter there, but it should work now with the changes that I
checked in recently to mount.cifs to fix the setuid behavior.

-- 
Jeff Layton <jlayton at redhat.com>