samba - May 2017 - Oplock break failed for file xxx -- replying anyway

Hi folks
   Recently I met a problem and found “Oplock break failed for file xxx --
replying anyway” in the log, here is the detail:

1）  Background：

A、 Client: windows 7 SP1（pc）

B、 Server: Samba 4.3.11

C、  Protocol: SMB2.1

2)       Phenomenon:

A、 I tried to open my shared directory, and found it was really slow to
open(needs 30 more seconds),(Lately I found that same lnk type files existed in
the dir, I guess this may be relevant)

B、 The MS office 2010（like word, ppt）also needed 30 more seconds to open（No lnk
file existed could also lead to this problem）

C、  Copying files in the shared directory also showed a really bad
performance(< 100KB/s)（No lnk file existed could also lead to this problem）

D、 The phenomenon above only happens in some clients, not in all the
clients(have not yet found the differences between those windows clients)

3)       Logs:
[2017/05/16 14:50:47.043884, 10, pid=606157, effective(65534, 65534),
real(65534, 0)] ../source3/smbd/smb2_break.c:474(send_break_message_smb2)
  send_break_message_smb2: sending oplock break for file aaa/sss.lnk, fnum
411557308, smb2 level 1
… …
… …
[2017/05/16 14:51:17.056975,  0, pid=606157, effective(0, 0), real(0, 0),
class=locking] ../source3/smbd/oplock.c:701(oplock_timeout_handler)
Oplock break failed for file aaa/sss.lnk -- replying anyway
  … …
  … …
  [2017/05/16 14:51:17.068473, 10, pid=606157, effective(65534, 65534),
real(65534, 0)] ../source3/smbd/smb2_server.c:2018(smbd_smb2_request_dispatch)
  smbd_smb2_request_dispatch: opcode[SMB2_OP_BREAK] mid = 52
[2017/05/16 14:51:17.068496,  4, pid=606157, effective(65534, 65534),
real(65534, 0)] ../source3/smbd/uid.c:384(change_to_user)
  Skipping user change - already user
[2017/05/16 14:51:17.068522, 10, pid=606157, effective(65534, 65534),
real(65534, 0)] ../source3/smbd/smb2_server.c:2789(smbd_smb2_request_error_ex)
  smbd_smb2_request_error_ex: idx[1] status[NT_STATUS_INVALID_OPLOCK_PROTOCOL]
|| at ../source3/smbd/smb2_break.c:78
[2017/05/16 14:51:17.068550, 10, pid=606157, effective(65534, 65534),
real(65534, 0)] ../source3/smbd/smb2_server.c:2680(smbd_smb2_request_done_ex)
  smbd_smb2_request_done_ex: idx[1] status[NT_STATUS_INVALID_OPLOCK_PROTOCOL]
body[8] dyn[yes:1] at ../source3/smbd/smb2_server.c:2837


4)       Analysis, solutions and doubts:

A、Analysis:

According to the logs above, it may be directly due to the oplock break timeout.
I guess for some reason samba may have detected the oplock being break, and then
sends an oplock break notification to the client and waiting for the Oplock
break acknowledgment until timeout(default OPLOCK_BREAK_TIMEOUT :30s). After
30s, although clients responds to samba, the NT_STATUS_INVALID_OPLOCK_PROTOCOL
will be returned as it is not oplock breaking time now.

B、Solutions：

I tried to set oplocks = no, and the problems did not happen until now, but
setting oplocks to no may affect the performance, so I do not want to try this
way.

I tried to set blocking locks = no, but it did not work.

C、Doubts

My doubts are:

I、               Why does samba send a oplock break notification to some windows
7 client? (As I do not find any oplock break requests when using some other
windows 7 clients)

II、             And why do those particular clients not respond to the
notification within the acquired time(default 30s)?

III、           Is it a samba bug or a windows client related problem?

IV、           Finally how can I solve this problem without affecting the
performance?


Looking forward to your reply, thanks!
Best regards!













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