Re: mtree acl support

On Jan 16, 2014, at 12:36 PM, Mark Felder <feld@freebsd.org> wrote:

> On Wed, Jan 15, 2014, at 23:11, Tim Kientzle wrote:
>> =

>> On Jan 14, 2014, at 6:47 AM, Mark Felder <feld@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.ht=
ml
>>> =

>>> 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 =91tar=92 has addressed (inspired by Joerg Schilling=92s
>> 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 is out of date.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 :-)

The extended format stores both name and numeric ID.

It tries to restore by name first (looking up as necessary), then falls bac=
k on ID if that fails.

So this does correctly handle your case.

This also lets you restore trees when user lookups are unavailable.  For ex=
ample, user lookups may be broken because of permission problems that you=
=92re trying to fix with mtree.  ;-)

Tim

_______________________________________________
freebsd-current@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-current
To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"