[Samba] Upgrade from 4.1.9 to 4.1.17

[Pásztor János]

Dear Members,

I would like to share my success story with a scheduled samba4 upgrade.

Our faculty domain contains one dc and two fileserver, plus the pc labor
windows machines(7 room * 25 machines). We use debian on the servers and
installed samba4 from stable backports.

Experiences:

* i could successfully apply the samdb.py and user.py pathces from
Rowland Penny. After that, the user creation worked as before
* for the first dc start i have to wait about 20 minutes. It was an
unpleasant suprise, i restarted samba many times, i thought i was stuck
into some loop.
At loglevel 10 i only saw some ldb operations and one cpu core went to
100% Example follows:

ldb: ldb_trace_next_request: (rdn_name)->modify
ldb: ldb_trace_next_request: (repl_meta_data)->modify
ldb: ldb_trace_next_request: (linked_attributes)->modify
ldb: ldb_trace_next_request: (partition)->modify
ldb: ldb_trace_next_request: (tdb)->modify
ldb: ldb_trace_next_request: (tdb)->search
ldb: ldb_trace_next_request: (schema_data)->del
ldb: ldb_trace_next_request: (tdb)->del
ldb: ldb_trace_next_request: (tdb)->del
ldb: ldb_trace_next_request: (tdb)->del

ldb: ldb_trace_next_request: (tdb)->del
ldb: ldb_trace_next_request: (tdb)->del
ldb: ldb_trace_next_request: (schema_data)->add
ldb: ldb_trace_next_request: (tdb)->add
ldb: ldb_trace_next_request: (tdb)->add
ldb: ldb_trace_next_request: (tdb)->add

I connected to the process with strace and i only saw this:

brk(0x7f0265025000)                     = 0x7f0265025000
brk(0x7f0265081000)                     = 0x7f0265081000
brk(0x7f02650dc000)                     = 0x7f02650dc000
brk(0x7f0265138000)                     = 0x7f0265138000

I think it was some kind of ldb upgrade/maintenance. It would be handy
to have some feedback or progess bar. I really don't like unresponsive
starts, especially after an upgrade...

If needed, i could past the whole debug log/samba config/etc...

* apart from the previous problem, the 4.1.17 version works as expected!

Regards,
János