[cifs-protocol] Replicating deleted object procedure clarifications

Obaid Farooqi obaidf at microsoft.com
Tue May 18 09:16:12 MDT 2010

Hi Kamen:
Thank you for contacting Microsoft regarding your question on deleted objects. A member of protocol documentation team will be in touch soon.

Obaid Farooqi
Sr. Support Escalation Engineer | Microsoft

From: kamenim at gmail.com [mailto:kamenim at gmail.com] On Behalf Of Kamen Mazdrashki
Sent: Tuesday, May 18, 2010 7:33 AM
To: Interoperability Documentation Help; cifs-protocol at samba.org; pfif at tridgell.net
Subject: Replicating deleted object procedure clarifications

Dear Dochelp,

I am currently trying to refactor Delete object implementation in Samba and I need some help
with algorithm used for deleting objects and how the deletion is replicated to other DCs.

 ProcessGetNCChangesReply [MS-DRSR] - http://msdn.microsoft.com/en-us/library/dd207758(v=PROT.13).aspx
    UpdateObject [MS-DRSR] - http://msdn.microsoft.com/en-us/library/dd207780(v=PROT.13).aspx
 Delete Operation [MS-ADTS] - http://msdn.microsoft.com/en-us/library/cc223480(v=PROT.13).aspx

Consider following sutiation:
0. We have two DCs configuration.
    We have an OU object with following props:
      dn: OU=TEST_DELETE_0417,DC=samba,DC=devel
      objectGUID: b7f1b90d-d247-45b7-87fb-f6bc916bd729

1. We delete this OU on DC1. The state of this object on each dc should be as follows:
      dn: OU=TEST_DELETE_0417\0ADEL:b7f1b90d-d247-45b7-87fb-f6bc916bd729,CN=Deleted Objects,DC=samba,DC=devel
      objectGUID: b7f1b90d-d247-45b7-87fb-f6bc916bd729
      isDeleted: TRUE
      isRecycled: TRUE
      dn: OU=TEST_DELETE_0417,DC=samba,DC=devel
      objectGUID: b7f1b90d-d247-45b7-87fb-f6bc916bd729

2. Replication is triggered from DC1 to DC2.
Now, according to UpdateObject() procedure, we will identify that Object's DN has changed from
"dn: OU=TEST_DELETE_0417,DC=samba,DC=devel"
to "dn: OU=TEST_DELETE_0417\0ADEL:b7f1b90d-d247-45b7-87fb-f6bc916bd729,CN=Deleted Objects,DC=samba,DC=devel".
Hence we will modify object's DN (calling PerformModifyDNOperation() operation).
Which will make this object a Deleted-object right?
While progressing further in UpdateObject() procedure, we will check and see, that 'isDeleted'
attribute value is TRUE, so we shall call RemoveObj() procedure. At this point I am a little bit puzzled as
there are two possible outcomes from this procedure:
1. Object's RDN should be transformed to a delete-mangled RDN. So we should end with an RDN like:
 TEST_DELETE_0417\0ADEL:b7f1b90d-d247-45b7-87fb-f6bc916bd72\0ADEL:b7f1b90d-d247-45b7-87fb-f6bc916bd72 right?
2. Or, as the object is already under "Deleted Object" container (moved there by previous call to PerformModifyOperation()),
RemoveObj() procedure should delete it further - i.e. if the object is a Tombstone, it will be completely removed.

Sorry that my description gets so messy.
Basically what UpdateObject() states is that first we should execute PerformModifyOperation() and then RemoveObj().
Which is a little bit confusing, as PerformModifyOperation() will turn the object into a Deleted-object.
Calling RemoveObj() later will actually act on already modified object, so I wonder - how does RemoveObj()
knows that we just converted the object and this object should not be completely removed?

Another possibility is for PeformModifyOperation() to determine that target DN will move the object under
"Deleted Objects" container, and in this case to modify only Attribute values on the object, but not to call
PerformModifyDNOperation() operation?

Kamen Mazdrashki
kamen.mazdrashki at postpath.com<mailto:kamen.mazdrashki at postpath.com>
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