FW: Sporadic permission denied error in Samba 4.3 and 4.4, 4.2 OK

[Youzhong Yang]

Got a bounce back, so resending the e-mail.

From: Youzhong Yang
Sent: Friday, November 04, 2016 10:39 AM
To: samba-technical at samba.org
Cc: Jeremy Allison <jra at samba.org>
Subject: Sporadic permission denied error in Samba 4.3 and 4.4, 4.2 OK

Hi Samba gurus,

We've been using Samba 4.2 in our production environment for more than one year and it's very stable and reliable.

There's no more fix going into 4.2 so we know it's time to upgrade, but unfortunately it turns out 4.3 and 4.4 (we haven't tried 4.5) have some kind of issues that bothered me quite a bit - our application sporadically complained about 'permission denied'. I switched back and forth between 4.2 and higher version, clearly 4.2 works well, and 4.3/4.4 doesn't.

I put a debug output at the end of create_file_default(), the error code I saw is NT_STATUS_SHARING_VIOLATION, here is one example:

[2016/11/03 20:23:55.180173,  0, pid=38541, class=open] ../source3/smbd/open.c:5170(create_file_default)
  create_file: access_mask = 0x120089 file_attributes = 0x80, share_access = 0x3, create_disposition = 0x1 create_options = 0x40 oplock_request = 0x100 private_flags = 0x0 fname = 480289_r000_win64_smoke_t/w s/480289_r000_win64_5/matlab/toolbox/matlab/testframework/core/+matlab/+unittest/+internal/+qualifications/QualificationFailedException.m NT_STATUS_SHARING_VIOLATION

To my understanding, NT_STATUS_SHARING_VIOLATION does not necessarily mean the Windows client will get a 'permission denied' error.

I am still trying very hard to reproduce this issue without using our application, so far no luck.

I am stuck right now, please shed some light on the issue if you would.

Thanks,

--Youzhong Yang