- How to export vfat partition correctly?

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Chris Carlen
07-24-2004, 10:07 PM
Hi:

I have a machine with two vfat partitions mounted as /w98 and /w98d and
in which / is an ext3.

My /etc/exports has these exported as well as / in the order /, /w98, /w98d.

Trouble is, even when root mounts the vfat partition, the ownership is
user1:users . No other users can see the files. What's wierder is
neither root nor user1 can change the permissions of /w98 or /w98d when
the partitions are mounted.

What would be the best strategy to make the /w98 and /w98d files
available to all users with rw perms?

Thanks for tips.

Good day!


--
_______________________________________________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarle@sandia.gov -- NOTE: Remove "BOGUS" from email address to reply.

Jeroen Geilman
07-24-2004, 10:07 PM
Chris Carlen <crcarle@BOGUS.sandia.gov> randomly warbled in
comp.os.linux.networking:

> Hi:
>
> I have a machine with two vfat partitions mounted as /w98 and /w98d
> and in which / is an ext3.
>
> My /etc/exports has these exported as well as / in the order /, /w98,
> /w98d.

That's...why ?

If you export /, then both /w98 and /w98d are exported as exactly that -
whether or not / itself is exported.

> Trouble is, even when root mounts the vfat partition, the ownership is
> user1:users .

(v)fat has no concept of ownership - YOU have to assign the uid/gid to
mount it with - if you care, since (v)fat doesn't grok this.

> No other users can see the files. What's wierder is
> neither root nor user1 can change the permissions of /w98 or /w98d
> when the partitions are mounted.

No indeedy - and I'll go one step further for you:
NOBODY can ever change the permissions on a mount point when that mount
point is in use, since you cannot reach the original mount point while
it has a filesystem mounted on it - it's just invisible.

As for changing the permissions of the mounted vfat partition...exactly
how many permissions do you think a vfat partition has ? ZERO ;-)

What you should do is SET the permissions you want in /etc/fstab - man
mount and read the options for fat.

Those will be the permissions given to the ENTIRE (v)fat filesystem,
since - again - (v)fat does not do permissions.

> What would be the best strategy to make the /w98 and /w98d files
> available to all users with rw perms?

change /etc/fstab to read:

/dev/hdxy /w98 rw,noatime,auto,umask=000

and similar for the second; this should make everything rw for anyone.

Now change /etc/exports to read:

/ (rw,insecure)

And you should be set!

Mount the yourhost:/ directory somewhere on a remote, and everybody and
his dog will have rw access.

--
Jeroen Geilman

All your bits are belong to us.

Chris Carlen
07-24-2004, 10:08 PM
Jeroen Geilman wrote:
> Chris Carlen <crcarle@BOGUS.sandia.gov> randomly warbled in
> comp.os.linux.networking:
>>I have a machine with two vfat partitions mounted as /w98 and /w98d
>>and in which / is an ext3.
>>My /etc/exports has these exported as well as / in the order /, /w98,
>>/w98d.
> That's...why ?
>
> If you export /, then both /w98 and /w98d are exported as exactly that -
> whether or not / itself is exported.

Unfortunately, it doesn't work that way on my machine. I have correctly
mounted the vfat at /w98 now using your assistance below. The remaining
issue is NFS exporting. If the subdirs of / to be exported are
different physical partitions than /, then they don't export with /.

Example, the server "ting" has the vfat mounted on /w98:

ting:/home/user1 # cat /etc/exports
/ 192.168.0.0/255.255.255.0(rw,insecure)

Now on the client machine "tong" I have in /etc/fstab:

ting:/w98 /ting nfs noauto,rw,hard,intr,user,exec 0 0

Now the client does:

user1@tong:~ $ mount /ting
user1@tong:~ $ l /ting
bin dev home lost+found mnt proc s73 srv tong var w98d
boot etc lib media opt root sbin tmp usr w98
user1@tong:~ $ l /ting/w98
user1@tong:~ $

Notice that it doesn't see anything that's mounted under ting:/w98

When I change the server /etc/exports to:

/ 192.168.0.0/255.255.255.0(rw,insecure)
/w98 192.168.0.0/255.255.255.0(rw)

Then add to the client /etc/fstab:

ting:/w98 /ting-w98 nfs noauto,rw,hard,intr,user,exec 0 0

user1@tong:~ $ mount /ting-w98
user1@tong:~ $ l /ting-w98
Program Files config.sys netlog.txt system.1st
Temp detlog.txt recycled unpack
autoexec.bat frunlog.txt scandisk.log windows[etc]

The same behavior takes place with CDROM mounts, who's mountpoints as
subdirs of / don't export with /, and must be explicitly mentioned in
/etc/exports.


> change /etc/fstab to read:
>
> /dev/hdxy /w98 rw,noatime,auto,umask=000

Yes. This gets the partition mounted on the server so that all have r/w
access. Good.

> / (rw,insecure)
>
> And you should be set!

But this part doesn't work, as described above, I must explicitly export
the /w98 mountpoint of the vfat to be able to nfs mount it on the client.

Can you explain what is going on with this?

Thanks for your input.

Good day!


--
_____________________
Christopher R. Carlen
crobc@earthlink.net
Suse 8.1 Linux 2.4.19

Tauno Voipio
07-24-2004, 10:09 PM
"Chris Carlen" <crobc@BOGUSFIELD.earthlink.net> wrote in message
news:bna63m02rvg@enews2.newsguy.com...
> Jeroen Geilman wrote:
> > Chris Carlen <crcarle@BOGUS.sandia.gov> randomly warbled in
> > comp.os.linux.networking:
> >>I have a machine with two vfat partitions mounted as /w98 and /w98d
> >>and in which / is an ext3.
> >>My /etc/exports has these exported as well as / in the order /, /w98,
> >>/w98d.
> > That's...why ?
> >
> > If you export /, then both /w98 and /w98d are exported as exactly that -
> > whether or not / itself is exported.
>
> Unfortunately, it doesn't work that way on my machine. I have correctly
> mounted the vfat at /w98 now using your assistance below. The remaining
> issue is NFS exporting. If the subdirs of / to be exported are
> different physical partitions than /, then they don't export with /.
>
> Example, the server "ting" has the vfat mounted on /w98:
>
> ting:/home/user1 # cat /etc/exports
> / 192.168.0.0/255.255.255.0(rw,insecure)
>
> Now on the client machine "tong" I have in /etc/fstab:
>
> ting:/w98 /ting nfs noauto,rw,hard,intr,user,exec 0 0
>

Just for check:

Are you trying to export a filesystem that is mounted from another host via
NFS?

It's not permitted. The reason is that the original exporter of the file
system has certain restrictions (in /etc/exports) on the possible users of
the filesystem, but a re-export at another host could render the original
restrictions useless.

HTH

Tauno Voipio
tauno voipio @ iki fi