mtree acl support

[Mark Felder]

On Wed, Jan 15, 2014, at 23:11, Tim Kientzle wrote:
> 
> On Jan 14, 2014, at 6:47 AM, Mark Felder <feld at freebsd.org> wrote:
> 
> > I was recently talking to someone about how one would backup / restore
> > ACLs reliably. I didn't see any mention of ACLs in the mtree man page
> > and after a quick google I came upon this old mailing list post:
> > 
> > http://lists.freebsd.org/pipermail/freebsd-hackers/2008-April/024173.html
> > 
> > patch in list is here: http://heka.cenkes.org/sat/diffs/mtree_acl.diff
> > I've mirrored it here: https://feld.me/freebsd/mtree_acl.diff
> > 
> > This old patch appears to still apply cleanly. I hate to see a patch die
> > and be forgotten.
> 
> One problem that ‘tar’ has addressed (inspired by Joerg Schilling’s
> work on star) is to permit ACLs to be restored even if the user database
> is out of date.
> 
> This is done by including a fourth field in each ACE with the
> numeric user ID.
> 
> I suspect you want to do the same for mtree.  I thought
> I remembered acl_to_text having an option to use
> an extended text format, so it might be a trivial change.
> 

As long as it's not default. One of the most convenient ways to change a
user's UID (or multiple users!) is to do an mtree backup, change
UID/GID, and then re-apply mtree backup. Every file that the user(s)
previously owned will be automatically changed to the new UID/GID for
you :-)