Lustre discuss - Feb 2010 - Restricting 'lfs setstripe' command + kernelpanic

Hello,

Is there a way to disable ''lfs setstripe'' on certain
directories/files for non-root users?

I noticed that nobody (not even root) is able to change the striping if i mount
lustre with user_xattr, so i suspect that there must be some xattr flag to
re-enable it on a per-user basis but i could not figure out how to do it.


Oh and btw: I discovered a very nice way to panic a lustre client with
a single command:

 $ setfattr -n lustre.lov .
 *boom!* (no need to be root. causes a kernelpanic on
          lustre 1.8.1.1 / linux 2.6.18-128.7.1.el5)


Regards,
 Adrian Ulrich

On 2010-02-25, at 10:51, Adrian Ulrich wrote:
> Is there a way to disable ''lfs setstripe'' on certain
> directories/files for non-root users?
No.
> I noticed that nobody (not even root) is able to
> change the striping if i mount lustre with user_xattr,
> so i suspect that there must be some xattr flag to
>  re-enable it on a per-user basis but i could not
> figure out how to do it.
This is unintentional.
> Oh and btw: I discovered a very nice way to panic a
> lustre client with a single command:
>
> $ setfattr -n lustre.lov .
> *boom!* (no need to be root. causes a kernelpanic on
>          lustre 1.8.1.1 / linux 2.6.18-128.7.1.el5)

It looks like we dereference the passed "value" (NULL in this case)  
without checking it.  It looks pretty trivial to fix.  I doubt this  
will panic the client, however.  It will cause the process thread to  
OOPS due to the NULL dereference, and that thread will hang, or  
possibly exit, but it shouldn''t cause any serious problems.

I''ve filed bug 22187 for this, thanks for reporting it.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.