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Andrea Venturoli

2019-Nov-13 12:11 UTC

[Samba] "samba-tool backup offline" stuck

On 2019-11-13 09:30, Andrew Bartlett wrote:
> Regarding your problem, on linux I use lslocks to debug from here, you
> can normally work out which process is holding the lock, which lock it
> is waiting on (if any, marked with a *) and gdb that to work out what
> is the matter with it, and perhaps why it is in that situation.
Hmm...

I have no lslocks on FreeBSD; will lsof do?

In case, here's an excerpt:> samba     72462      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72462      root   46u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72466      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72466      root    8u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72469      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72469      root   32u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> winbindd  72475      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> winbindd  72475      root   12u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72476      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72476      root   25u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72487      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72487      root    8u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72488      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72488      root    8u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72489      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72489      root    8u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72494      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> smbd      72494      root    8u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72496      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72496      root   46u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72497      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72497      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72692      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72692      root   46u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72696      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72696      root   46u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72697      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72697      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72882      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     72882      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     73535      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     73535      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     73536      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     73536      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     73895      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     73895      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     76100      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     76100      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     76103      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     76103      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     85298      root  txt     VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
> samba     85298      root   35u    VREG       4,1302659313            
430080   32007 /usr/jails/dc/var/db/samba4/private/secrets.tdb
IIUIC, it seems I have around 20 processes using secrets.tdb read/write, 
but no locks!

So I tried stopping Samba completely: now no process has secrets.tdb 
open; still tdbbackup gets stuck in _fcntl!!!

I'm open to suggestions...

  bye & Thanks
	av.

Andrea Venturoli

2019-Nov-21 13:58 UTC

head link

[Samba] "samba-tool backup offline" stuck

On 2019-11-13 13:11, Andrea Venturoli wrote:
> I'm open to suggestions...
Some further step...

It's samba-tool itself that locks the file before calling tdbbackup.

Running "samba-tool domain backup offline ..." spawns "tdbbackup
-s
.copy.tdb /var/db/samba4/private/secrets.ldb -r", which gets stuck.

Running "tdbbackup -s .copy.tdb /var/db/samba4/private/secrets.ldb -r"
by itself completes without issues.



I read in domain_backup.py:
>     # Secrets databases are a special case: a transaction must be started
>     # on the secrets.ldb file before backing up that file and secrets.tdb
>     def backup_secrets(self, private_dir, lp, logger):
>         secrets_path = os.path.join(private_dir, 'secrets')
>         secrets_obj = Ldb(secrets_path + '.ldb', lp=lp)
>         logger.info('Starting transaction on ' + secrets_path)
>         secrets_obj.transaction_start()
>         self.offline_tdb_copy(secrets_path + '.ldb')
>         self.offline_tdb_copy(secrets_path + '.tdb')
>         secrets_obj.transaction_cancel()
Could the problem be here?
I'm not attempting to alter this, before understanding it fully, though.


  bye & Thanks
	av.

Andrew Bartlett

2019-Nov-21 17:20 UTC

head link

[Samba] "samba-tool backup offline" stuck

On Thu, 2019-11-21 at 14:58 +0100, Andrea Venturoli
wrote:> On 2019-11-13 13:11, Andrea Venturoli wrote:
> 
> > I'm open to suggestions...
> 
> Some further step...
> 
> It's samba-tool itself that locks the file before calling tdbbackup.
> 
> Running "samba-tool domain backup offline ..." spawns
"tdbbackup -s
> .copy.tdb /var/db/samba4/private/secrets.ldb -r", which gets stuck.
> 
> Running "tdbbackup -s .copy.tdb /var/db/samba4/private/secrets.ldb
-r"
> by itself completes without issues.
> 
> 
> 
> I read in domain_backup.py:
> 
> >     # Secrets databases are a special case: a transaction must be
started
> >     # on the secrets.ldb file before backing up that file and
secrets.tdb
> >     def backup_secrets(self, private_dir, lp, logger):
> >         secrets_path = os.path.join(private_dir, 'secrets')
> >         secrets_obj = Ldb(secrets_path + '.ldb', lp=lp)
> >         logger.info('Starting transaction on ' + secrets_path)
> >         secrets_obj.transaction_start()
> >         self.offline_tdb_copy(secrets_path + '.ldb')
> >         self.offline_tdb_copy(secrets_path + '.tdb')
> >         secrets_obj.transaction_cancel()
> 
> Could the problem be here?
> I'm not attempting to alter this, before understanding it fully,
though.
Is tdbbackup the one provided by the Samba build, or an earlier
(system) version?

We had to change the lock behaviour in tdb to make this work, if you
ran an older version it would do as you note. 

Andrew Bartlett
-- 
Andrew Bartlett                       http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba

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