[Bug-tar] xattr support from Fedora

[Andreas Dilger]

Hello,
I'm new to this list (subscription still pending, please CC), and have
some questions about the xattr patch from James Antill of Red Hat that
I couldn't find any answers to in the mailing list (searched for "xattr").

Are there any plans to incorporate the xattr support into the upstream
version of GNU tar?  If not, are there specific objections to that patch
that could be fixed in order to make it acceptable, or are there alternate
plans to provide xattr support?

I'm personally less interested in ACL support, and not at all in SELinux
support, so if there are objections to those specifically, would there be
a chance to accept just the basic xattr support (user.* and trusted.*
namespaces)?

After the patch posting by James last year (Mar 27, 2007 "Xtar deficiency")
the only reply was from Jörg Schilling of star saying the patch "looked
non-portable", but no specifics.



On a related note, what are people's thoughts to change the aforementioned
tar+xattr code so that files had the xattrs set on them _before_ the
data was written into the file?  This makes sense from the point of tar,
because the xattr data is stored earlier in the archive, instead of
having to save it in memory until the file data is written.

We hope to use this for Lustre (a GPL clustered filesystem for Linux,
commonly used in HPC clusters) in order to have the ability to use xattrs
to save and restore the file layout (i.e. on which server(s) the file is
stored) before the data is written to disk.  In the near future, pNFS will
have a similar desire to be able to restore the file layout from a backup
before the data is written to the server(s).

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