[cifs-protocol] [REG:110051857479854] RE: Replicating deleted object procedure clarifications

Hongwei Sun hongweis at microsoft.com
Fri May 21 17:40:14 MDT 2010


   For your question regarding the algorithm used in UpdateObject() , as documented in of MS-DRSR,  I think that the RemoveObj()  was performed after PerformModifyOperation just to ensure the attributes on the deleted object conform to the invariants of a tombstone or deleted-object(see 3.1..1.5.5 of  MS-ADTS).   This is mentioned in the comments of the algorithm before RemoveObj is called.    Furthermore, as per 5.154 of MS-DRSR, RemoveObj procedure performs a delete operation on an object so the targeted object will be transformed to a deleted-object or a tombstone ,depending on the state of the Recycle Bin option feature.  This includes modifying the attributes and moving into the Deleted Container of its NC.  But it will not remove the objects from the directory directly.    If the object after PerformModifyOperation already conforms to the invariant of deleted-object or tombstone,  the RemoveObj may do nothing to the object.

  Please let me know if I understand you question properly and if you have further questions.



From: cifs-protocol-bounces at cifs.org [mailto:cifs-protocol-bounces at cifs.org] 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: [cifs-protocol] 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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