Lustre discuss - Jun 2010 - File access question

Hello,

I am trying to understand the way in which a file on a lustre (1.6.7)
file system is accessed.

I have a legitimate need to have an executable file execute-only; no
read permission at all.  Testing on ext3 I can do this by "chmod 110
a.out".   A user in the group is able to successfully execute the
file.   If I attempt to do the same thing on a Lustre file system I
see the error message "Permission denied".   I can gain access by
setting the g+r.  That last setting is not permissible for this
specific file.   In trying to understand how this works I selected the
on-line Lustre 1.8.x Manual (
http://wiki.lustre.org/manual/LustreManual18_HTML/IntroductionToLustre.html
).  Figure 1.5 seemed to indicate that a read operation to get the
pointers to pass back to the client is required.   Essentially because
of the separation of metadata from the file system on which the data
file actually physically resides an "execute-only"  file on a Lustre
file system is not possible.

Is this thinking correct?

Thank you,
Megan Larko

(now with SGI Federal)

You can have execute-only files on Lustre, but do see
https://bugzilla.lustre.org/show_bug.cgi?id=22376 for this issue 
reported with v1.8

Kevin


Ms. Megan Larko wrote:
> Hello,
>
> I am trying to understand the way in which a file on a lustre (1.6.7)
> file system is accessed.
>
> I have a legitimate need to have an executable file execute-only; no
> read permission at all.  Testing on ext3 I can do this by "chmod 110
> a.out".   A user in the group is able to successfully execute the
> file.   If I attempt to do the same thing on a Lustre file system I
> see the error message "Permission denied".   I can gain access by
> setting the g+r.  That last setting is not permissible for this
> specific file.   In trying to understand how this works I selected the
> on-line Lustre 1.8.x Manual (
> http://wiki.lustre.org/manual/LustreManual18_HTML/IntroductionToLustre.html
> ).  Figure 1.5 seemed to indicate that a read operation to get the
> pointers to pass back to the client is required.   Essentially because
> of the separation of metadata from the file system on which the data
> file actually physically resides an "execute-only"  file on a
Lustre
> file system is not possible.
>
> Is this thinking correct?
>
> Thank you,
> Megan Larko
>
> (now with SGI Federal)
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>