[Samba] Problem with not fixable dangling forward links

[Achim Gottinger]

Am 25.11.2017 um 18:00 schrieb Achim Gottinger via samba:
>
>
> Am 25.11.2017 um 16:55 schrieb Achim Gottinger via samba:
>>
>>
>> Am 25.11.2017 um 04:39 schrieb Andrew Bartlett:
>>> On Fri, 2017-11-24 at 11:55 +1300, Andrew Bartlett via samba wrote:
>>>> On Tue, 2017-11-21 at 11:21 +0100, Achim Gottinger via samba wrote:
>>>>> Hello List,
>>>>>
>>>>> In preparation to update my samba ad-dc's running debian wheezy with
>>>>> backported samba 4.6.8 to 4.7.3.
>>>>> I'd like to fix two errors showing up in dbcheck whom hab been 
>>>>> reported
>>>>> by dbckech --cross-ncs for an long time but without causing any 
>>>>> issues
>>>>> so far.
>>>>>
>>>>> I'm getting this error on my main dc
>>>>>
>>>>> root at server:~# samba-tool dbcheck --cross-ncs
>>>>> Checking 4188 objects
>>>>> ERROR: no target object found for GUID component for siteList in 
>>>>> object
>>>>> CN=DEFAULTIPSITELINK,CN=IP,CN=Inter-Site
>>>>> Transports,CN=Sites,CN=Configuration,DC=samba-list,DC=loc -
>>>>> <GUID=d4f41749a1595a43871ab1d72f24fe6b>;<RMD_ADDTIME=130015150890000000>;<RMD_CHANGETIME=130015150890000000>;<RMD_FLAGS=0>;<RMD_INVOCID=af301252bb781543b57dbd7cb773d46f>;<RMD_LOCAL_USN=4762>;<RMD_ORIGINATING_USN=4762>;<RMD_VERSION=0>;CN=Test,CN=Sites,CN=Configuration,DC=samba-list,DC=loc 
>>>>>
>>>>> Not removing dangling forward link
>>>>> ERROR: no target object found for GUID component for siteList in 
>>>>> object
>>>>> CN=DEFAULTIPSITELINK,CN=IP,CN=Inter-Site
>>>>> Transports,CN=Sites,CN=Configuration,DC=samba-list,DC=loc -
>>>>> <GUID=596bd8ae9e8bc94eab99ad3c12e22132>;<RMD_ADDTIME=130739077850000000>;<RMD_CHANGETIME=130739077850000000>;<RMD_FLAGS=0>;<RMD_INVOCID=af301252bb781543b57dbd7cb773d46f>;<RMD_LOCAL_USN=453494>;<RMD_ORIGINATING_USN=453494>;<RMD_VERSION=0>;CN=Grafing,CN=Sites,CN=Configuration,DC=samba-list,DC=loc 
>>>>>
>>>>> Not removing dangling forward link
>>>>> Please use --fix to fix these errors
>>>>> Checked 4188 objects (2 errors)
>>>> If these issues don't cause you replication failures or any other
>>>> issue, then you can ignore them.  In general, don't edit the backend
>>>> DB.
>>>>
>>>> However we have patches the fix some of this currently under review,
>>>> which will then be backported.
>>>>
>>>> I hope this helps.
>>> These patches are now in master and I see metze already has a branch
>>> for 4.7 so I expect those to be backported soon.
>>>
>>> Andrew Bartlett
>> Thank you for the info's Andrew!
>> I already damaged the sam db onec trying to use ldb edit to remove 
>> deleted objects, thats why asked if in this case an dbcheck --reindex 
>> will fix it.
>> But since they cause no problems with 4.6 i read your replay as they 
>> will not cause problems on 4.7 as well. So I'll try to update this 
>> weekend and report back.
>>
>> Achim~
>>
> All seven dc's updated and so far no issues. dbckeck did not find any 
> new errors beside the siteList objects. Replication works and also 
> uploading drivers form 32 and 64 bit (windows 7) clients, so the 32bit 
> client driver upload patch is no longer neccessary.
> If someone is interested in the wheezy backports i can update my 
> github samba-wheezy repo.
>
> Achim
I got abit adventurous and deleted the two siteList attributes on my 
main ad-dc which has all fsmo roles.

First I stopped amba and made an backup of sam.ldb and samb.ldb.d.

Next I edited sam.ldb.d/CN=CONFIGURATION,DC=SAMBA-LIST,DC=LOC.ldb and 
reindexed the db

#~ldbedit -e nano -H 
/varLib/samba/private/sam.ldb.d/CN=CONFIGURATION,DC=SAMBA-LIST,DC=LOC.ldb
#~samba-tool dbcheck --reindexdb

Now the errors are gone on the fsmo master. Earlier I had created and 
delete an other Site with the window Sites and Services tool. Running 
samba-tool dbcheck --cross-ncs now reported missing siteLinks to this 
Site but since the site object itself was accessible as an delete object 
running samba-tool dbcheck --cross-ncs --fix fixed that error.  So the 
fsmo master was now error free.

On an othe ad-dc however it still showed the missing siteList for the 
object wirth the missing target and also for the deleted object.
So I ran
#~samba-tool drs replicate --full-sync server2 server1 
CN=Configuration,DC=gsg,DC=local
to replicate the clean NC and after running dbcheck --cross-ncs --fix 
all errors where gone.
Repeated that on the remaining five dc's and now they are all error 
free. Till now replication is still working between all of them.