Chown and NFS between fc13 systems.

[GreggBz]

Hi Fedora Community

I'm having problems with chown on a mounted nfs volume between two fc13 systems.
I can mount the volume no problem. I can create files as root, but I cannot change their ownership.

I get this error:
chown: changing ownership of `test': Invalid argument

The line in the nfs server export file is:

/backup/client 192.168.0.1(rw,anonuid=65534,anongid=65534,no_root _squash)

The server's kernel:
2.6.33.3-85.fc13.x86_64

The client's kernel:
2.6.33.4-95.fc13.i686.PAE

The client and the server are on the same subnet with no firewalls running. SELinux is set to permissive on both systems.

Maybe I'm missing something simple?

[stevea]

anonuid=65534,anongid=65534 are unnecessary - those are the default values.


I have a similar config and I don't have any trouble doing chown.

Could you post a complete example.
touch a file, ls -l it, try to chown it.

[GreggBz]

Here you are:

[root@raven ~]# cd /mnt/rsync/
[root@raven rsync]# touch test
[root@raven rsync]# ls -l test
-rw-r--r--. 1 nobody nobody 0 Jul 29 14:13 test
[root@raven rsync]# chown voip:voip test
chown: changing ownership of `test': Invalid argument
[root@raven rsync]#

My troubles seem to come from my ignorance of NFSv4, which is completely different than old NFS.

http://blogs.sun.com/tdh/entry/chown...sername_spaces
http://nfsv4.bullopensource.org/doc/..._migration.pdf

In NFSv4, the UID is changed in a different way. It's done with SETATTR with the name and the domain. With NFSv3, it basically just changes the UID and GID to the corresponding number in the clients user table. Since the user voip does not exist on the server in my example, it fails. I'm not quite sure how to solve this problem since I'm using this NFS server to back up a large number of clients with lots of different users that the server is not going to know about. Until now, the clients that had older distrabutions worked fine. The first one with NFSv4 fails.

It looks like I could have fun with LDAP to maintain a user database.
I'm still looking for a HOWTO, or better yet, an easy solution that let's me mount the server in "NFSv3" mode or something.

---------- Post added at 02:15 PM CDT ---------- Previous post was at 01:24 PM CDT ----------

There is a vers=3 option in the mount command that has solved my issue.

Ugh.

[sej7278]

isn't name/uid mapping what rpcidmapd does?

i tend to create the users on all my systems with the same uid's for just this kind of thing (rsync has similar issues). not practical on a large network without ldap or somesuch i guess.

i justed tested creating a file on an nfs4 mount and the uid/gid were correct when doing an ls -l on the server, but then for that user the uid/gid are the same on both machines, so doesn't prove much.

[kurtseifried]

The solution is to ensure that idmapd is enabled on both the server and the client. In Fedora 16:

# systemctl enable nfs-idmap.service
# systemctl start nfs-idmap.service

[lightman47]

There's a syntax for chown I'd not seen before - hmm. I'd always used:
chown {ownername} test