[Samba] Samba 4: Issues with Linux clients (CIFS timeouts)

Frederik Vogelsang frederik.vogelsang at gmail.com
Fri Nov 2 11:35:13 MDT 2012


Hi,

I have set up Samba 4 to act as a standalone AD domain controller and
this setup is working so far. Windows clients work like a charm, even
group policy and advanced stuff, which is pretty exciting. What is
still causing a lot of pain are the Linux clients. Authentication
works great (pam_krb5 & nss_ldap) and the users can even mount shares
with their Kerberos credentials.

Now the issue is that when the users access their home folders
*sometimes* directory/file lookups fail or stall, which is causing
apps to crash. After two minutes files and folders on CIFS shares can
be accessed again, but only for a random period of time. After a while
these timeouts are coming back, this is what I get in dmesg on the
Linux client:

CIFS VFS: Server horst has not responded in 120 seconds. Reconnecting...
CIFS VFS: Unexpected lookup error -112

It looks like these timeouts happen when there is a lot of I/O load on
the CIFS shares. This is the output of log.smbd when a freeze happens:

[2012/11/02 18:19:12.454597,  2] ../source3/smbd/open.c:899(open_file)
  TESTDOMAIN\testuser opened file files/sample.txt read=Yes write=No (numopen=1)
[2012/11/02 18:19:12.455161,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 173 of length 63 (0 toread)
[2012/11/02 18:19:12.455206,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.455255,  3] ../source3/smbd/reply.c:3841(send_file_readX)
  send_file_readX fnum 13004 max=65536 nread=65536
[2012/11/02 18:19:12.459192,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 174 of length 63 (0 toread)
[2012/11/02 18:19:12.459259,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.464500,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 175 of length 63 (0 toread)
[2012/11/02 18:19:12.464549,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.476760,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 176 of length 63 (0 toread)
[2012/11/02 18:19:12.476829,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.501988,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 177 of length 63 (0 toread)
[2012/11/02 18:19:12.502039,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.546623,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 178 of length 63 (0 toread)
[2012/11/02 18:19:12.546692,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.619302,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 179 of length 63 (0 toread)
[2012/11/02 18:19:12.619371,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.677597,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 180 of length 63 (0 toread)
[2012/11/02 18:19:12.677664,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.719097,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 181 of length 63 (0 toread)
[2012/11/02 18:19:12.719166,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.766312,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 182 of length 63 (0 toread)
[2012/11/02 18:19:12.766380,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.810994,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 183 of length 63 (0 toread)
[2012/11/02 18:19:12.811063,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.848722,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 184 of length 63 (0 toread)
[2012/11/02 18:19:12.848791,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.886421,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 185 of length 63 (0 toread)
[2012/11/02 18:19:12.886488,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.925811,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 186 of length 63 (0 toread)
[2012/11/02 18:19:12.925879,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:12.973718,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 187 of length 63 (0 toread)
[2012/11/02 18:19:12.973787,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:13.040761,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 188 of length 63 (0 toread)
[2012/11/02 18:19:13.040830,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBreadX (pid 11302) conn 0x1598260
[2012/11/02 18:19:13.041172,  3] ../source3/smbd/reply.c:3841(send_file_readX)
  send_file_readX fnum 13004 max=475136 nread=472741

[2012/11/02 18:19:28.283505,  2] ../source3/smbd/server.c:436(remove_child_pid)
  Could not find child 11310 -- ignoring
[2012/11/02 18:19:28.473748,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 189 of length 78 (0 toread)
[2012/11/02 18:19:28.473821,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBtrans2 (pid 11302) conn 0x1598260
[2012/11/02 18:19:28.473860,  3]
../source3/smbd/trans2.c:5217(call_trans2qfilepathinfo)
  call_trans2qfilepathinfo: TRANSACT2_QPATHINFO: level = 512
[2012/11/02 18:19:28.473902,  3] ../source3/smbd/vfs.c:1118(check_reduced_name)
  check_reduced_name [.] [/mnt/test]
[2012/11/02 18:19:28.473938,  3] ../source3/smbd/vfs.c:1248(check_reduced_name)
  check_reduced_name: . reduced to /mnt/test
[2012/11/02 18:19:28.473981,  3]
../source3/locking/share_mode_lock.c:408(fetch_share_mode_unlocked)
  Could not fetch share entry
[2012/11/02 18:19:28.474011,  3]
../source3/smbd/trans2.c:5362(call_trans2qfilepathinfo)
  call_trans2qfilepathinfo . (fnum [fsp is NULL]) level=512 call=5 total_data=0
[2012/11/02 18:19:37.799385,  3] ../source3/smbd/process.c:1789(process_smb)
  Transaction 36 of length 42 (0 toread)
[2012/11/02 18:19:37.799466,  3] ../source3/smbd/process.c:1392(switch_message)
  switch message SMBecho (pid 29523) conn 0x0
[2012/11/02 18:19:37.799527,  3] ../source3/smbd/reply.c:5383(reply_echo)
  echo 1 times


I have tried many different kernels (currently on 3.7-rc3) and the
problem persists. I believe that this is Samba 4 issue, because with
Samba 3 I did not encounter any of these timeouts. Are there any
thoughts what could be going wrong here? Are there any options I
should set somewhere?


Regards,
 Frederik


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