Bug 9051 - Samba locks files and silently remove them, causing data loss
Samba locks files and silently remove them, causing data loss
Product: Samba 3.6
Classification: Unclassified
Component: File services
All Linux
: P5 critical
: ---
Assigned To: Volker Lendecke
Samba QA Contact
Depends on:
  Show dependency treegraph
Reported: 2012-07-18 21:40 UTC by Saulo Toledo
Modified: 2014-07-17 07:34 UTC (History)
2 users (show)

See Also:

smb.conf example file for samba 3.6.6 (4.59 KB, application/octet-stream)
2012-07-18 21:40 UTC, Saulo Toledo
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Description Saulo Toledo 2012-07-18 21:40:21 UTC
Created attachment 7710 [details]
smb.conf example file for samba 3.6.6

I have a Samba 3.6.6 installation. This problem occurs:

1) An user creates an image file, FILE.PSD;
2) A second user opens the file FILE.PSD;
3) The first user can't edit the file anymore.

In this installation, all is forced to user "arquivos" with permission 770. At Linux, I'm using ext3 without acl.

There's no special unix permission, no ACL, but samba deny the file access from first user to the file.

I've added "nt acl support = false" to smb.conf, but no result. I'm unable to identify at samba logs why the file is blocked: I can't find information about the problem.
This Samba uses LDAP to auth users.

The "net groupmap list" output for this samba installation:

Account Operators (S-1-5-21-2455266176-1594837443-3197790934-548) -> Account Operators
Administrators (S-1-5-21-2455266176-1594837443-3197790934-544) -> Administrators
Backup Operators (S-1-5-21-2455266176-1594837443-3197790934-551) -> Backup Operators
Domain Admins (S-1-5-21-2455266176-1594837443-3197790934-512) -> Domain Admins
Domain Computers (S-1-5-21-2455266176-1594837443-3197790934-515) -> Domain Computers
Domain Guests (S-1-5-21-2455266176-1594837443-3197790934-514) -> Domain Guests
Domain Users (S-1-5-21-2455266176-1594837443-3197790934-513) -> Domain Users
Print Operators (S-1-5-21-2455266176-1594837443-3197790934-550) -> Print Operators
Replicators (S-1-5-21-2455266176-1594837443-3197790934-552) -> Replicators
Comment 1 Saulo Toledo 2012-09-17 18:00:51 UTC
I'm running now Samba 3.6.7. The problem persists.

At shares I'm using:

        oplocks = False
        level2 oplocks = False
        locking = no
        strict locking = no
        blocking locks = no

Now Samba locks the file and, when the process terminate at server, the file is REMOVED. Then, I'm loosing files, especially if they are large, when the locks occurs with frequence.

I'm not certainly about how happens... the frequency is with .PSD photoshop
files, but can occurs with other files sporadically, but it's difficult
While using Adobe Photoshop, if at least 2 people opens the same file, the
file still locked, and remains inacessible and, now, is removed after the
first time the locked message occurs. At Adobe Photoshop, I see the message
I have no permission to access the file. After this, when the file is
removed after the process ends at server, It's possible save again. If I
forget save the file, it's lost.

I don't know how to measure the time, but I'm certainly if the second opens
when the first is opened (and this can be seconds of difference), the bug
happens. But happened in times I don't understood yet.

If the first client disconnects, the file still locked forever. To don't
lost the file, I can copy at server with another name, for example... The
same happens if the first machine is shut down...

Please let me know how can I post here better backtraces or some additional information. Samba is making me loose important data, and I need solve this as fast I can.
Comment 2 Andrew Bartlett 2012-09-17 18:11:17 UTC
This looks like expected behaviour of share modes to me.  Reopen it if behaviour of windows is any different.
Comment 3 Saulo Toledo 2012-09-17 18:57:25 UTC
(In reply to comment #2)
> This looks like expected behaviour of share modes to me.  Reopen it if
> behaviour of windows is any different.

I'm reopening and editing the report title. The previous title wasn't clear about the real problem.

All shares are with the default option (share modes = yes) and, when 2 users open files, the file is silently removed without ask the user about this. There are data loss. And the file can be locked for days, even the second user try change it and be removed. This is not a normal behavior.

This happens with frequency as larger are the files.
Comment 4 Jeremy Allison 2012-09-17 19:02:26 UTC
In order to investigate we need an isolated, reproducible test environment using only 2 clients (to demonstrate files being deleted incorrectly).

Please set that up and describe exactly how this is done. Also attach debug level 10 logs from the 2 smbd servers (one for each of the 2 clients) and also full network capture traces on tcp port 445 from each client to the server.

Without this there isn't enough data to do anything with this bug report.