[gentoo-user] NFS mounts and uid/gid/user names

[gentoo-user] NFS mounts and uid/gid/user names

[meino.cramer]

Hi,

to not to stress the SD-card of my single board computer too much I
mounted a directory of my PC via NFS at my single board computer, so
that compilations and other task which need to be done while
installing will access the hd and not the SD-card.
(The singleboard computer is a Cortex A8/OMAP based one: 32 bit. The
PC is 64 bit AMD based.)

So far so nice...everything works fine: I can see the directory
on both ends.

In /etc/exports on the PC I entered this:
/tmp/NFS 192.168.178.25(async,rw,no_subtree_check)

When setting chmod 700 /tmp/NFS, chown root:root /tmp/NFS
on the server side (PC) I cannot write to the directory
as root on the client side (single board computer).
On both sides root is 0:0.

When setting chmod 777 /tmp/NFS on the server side, I am able to write
at the client side to the that directory, bit listing that files shows
me that they become owned by nobody:nobody which is
nobody:x:65534:65534:nobody:/nonexistent:/bin/sh on the server side.

How can I acchieve, that files written on one side remain the same
uid/gid assignment on the other side?

Thank you very much in advance for any help!

Have a nice weekend!
Best regards,
mcc

Re: [gentoo-user] NFS mounts and uid/gid/user names

[Neil Bothwick]

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On Sat, 25 Aug 2012 00:56:41 +0200, meino.cramer@gmx.de wrote:

> In /etc/exports on the PC I entered this:
> /tmp/NFS 192.168.178.25(async,rw,no_subtree_check)
> 
> When setting chmod 700 /tmp/NFS, chown root:root /tmp/NFS
> on the server side (PC) I cannot write to the directory
> as root on the client side (single board computer).
> On both sides root is 0:0.
> 
> When setting chmod 777 /tmp/NFS on the server side, I am able to write
> at the client side to the that directory, bit listing that files shows
> me that they become owned by nobody:nobody which is
> nobody:x:65534:65534:nobody:/nonexistent:/bin/sh on the server side.

Where did you get the no_subtree_check options from? If you'd read it in
the man page you'd have seen that you also need no_root_squash. Without
this option, the root user on the client is mapped to a non-root user on
the server.


-- 
Neil Bothwick

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Re: [gentoo-user] NFS mounts and uid/gid/user names

[Alex Schuster]

meino.cramer@gmx.de writes:

> to not to stress the SD-card of my single board computer too much I
> mounted a directory of my PC via NFS at my single board computer, so
> that compilations and other task which need to be done while
> installing will access the hd and not the SD-card.
> (The singleboard computer is a Cortex A8/OMAP based one: 32 bit. The
> PC is 64 bit AMD based.)
>
> So far so nice...everything works fine: I can see the directory
> on both ends.
>
> In /etc/exports on the PC I entered this:
> /tmp/NFS 192.168.178.25(async,rw,no_subtree_check)
>
> When setting chmod 700 /tmp/NFS, chown root:root /tmp/NFS
> on the server side (PC) I cannot write to the directory
> as root on the client side (single board computer).
> On both sides root is 0:0.
>
> When setting chmod 777 /tmp/NFS on the server side, I am able to write
> at the client side to the that directory, bit listing that files shows
> me that they become owned by nobody:nobody which is
> nobody:x:65534:65534:nobody:/nonexistent:/bin/sh on the server side.
>
> How can I acchieve, that files written on one side remain the same
> uid/gid assignment on the other side?

Add 'root_no_squash' to your options in /etc/exports.

> Have a nice weekend!

Will do!

	Wonko