Re: [Bug-tar] Suprising behavior of extract with --xattrs

[Andreas Dilger]

On Jun 3, 2019, at 2:27 PM, Brian Murray <address@hidden> wrote:
> 
> When enabling extended attribute support in a tar file (--xattrs) all
> extended attributes are stored in the archive, however when the same archive
> is extracted only the user.* extended attributes are extracted. To have all
> the extended attributes read and applied on extraction one must also use the
> '--xattrs-include=*' option. I find this behavior surprising and especially so
> given that the documentation indicates that "By default, when `--xattr' is
> used, all names are stored in the archive (or extracted, if using
> `--extract')"[1].
> 
> I'm happy to help working on resolving this issue but it isn't clear to me
> whether the program or the documentation is incorrect. I've read some of this
> mailing list's archive but didn't find an explanation as to why restoration of
> only 'user.*' extended attributes would not be a bug[2].
> 
> [1] https://www.gnu.org/software/tar/manual/tar.html#SEC70
> [2] Which I reported here https://savannah.gnu.org/bugs/index.php?56421

As Pavel mentioned, it isn't necessarily safe/correct to extract all xattrs,
especially in cross-platform usage.  However, it *does* make sense to save
all of the xattrs, since it is then possible to extract whichever ones that
are useful.  If the xattrs aren't saved at time of archive creation, they
may be permanently lost.

Cheers, Andreas

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