When I turn on log level to 10, I discover the conversion error that slow down the file server especially browsing folder with 1000+ files.

So, I have tried testing in a real production environment by the following steps to demonstrate the problem.

1.  In smb.conf,
     I create a share called Chinese and increase the log level to 10.
	[global]
		workgroup = YAUOICHURCH
		realm = SAMBA4.YAUOI.ORG
		netbios name = FILE
		server role = active directory domain controller
		dns forwarder = 192.168.107.1
		log level = 10
		unix charset = UTF8
		dos charset = CP950
	[netlogon]
		path = /usr/local/samba/var/locks/sysvol/samba4.yauoi.org/scripts
		read only = No
	[sysvol]
		path = /usr/local/samba/var/locks/sysvol
		read only = No
...
	[Chinese]
		path = /home/chinese
		read only = No

2.  In the file server, I have created a directory /home/chinese and also, inside it, I have opened a folder called "中文測試" and I have tested the name is in UTF-8.

3.  I made use of Windows 7 64-bit Traditional Chinese as client to try to browse the share Chinese and then the folder (the client has joined the domain already) and I install wireshark to capture the packet.

4.  the log.smbd still show
[2013/02/14 15:58:33.556194,  3, pid=9621, effective(0, 100), real(0, 0)] ../lib/util/charset/convert_string.c:316(convert_string_handle)
  convert_string_internal: Conversion error: Illegal multibyte sequence(中æ<96><87>測試)
[2013/02/14 15:58:33.557036,  3, pid=9621, effective(0, 100), real(0, 0)] ../lib/util/charset/convert_string.c:297(convert_string_handle)
  convert_string_internal: Conversion error: Incomplete multibyte sequence(¸­æ<96><87>測試)
[2013/02/14 15:58:33.557877,  3, pid=9621, effective(0, 100), real(0, 0)] ../lib/util/charset/convert_string.c:297(convert_string_handle)
  convert_string_internal: Conversion error: Incomplete multibyte sequence(­æ<96><87>測試)
[2013/02/14 15:58:33.558715,  3, pid=9621, effective(0, 100), real(0, 0)] ../lib/util/charset/convert_string.c:316(convert_string_handle)
  convert_string_internal: Conversion error: Illegal multibyte sequence(æ<96><87>測試)
[2013/02/14 15:58:33.559624,  3, pid=9621, effective(0, 100), real(0, 0)] ../lib/util/charset/convert_string.c:297(convert_string_handle)
  convert_string_internal: Conversion error: Incomplete multibyte sequence(<96><87>測試)
[2013/02/14 15:58:33.560473,  3, pid=9621, effective(0, 100), real(0, 0)] ../lib/util/charset/convert_string.c:297(convert_string_handle)
  convert_string_internal: Conversion error: Incomplete multibyte sequence(<87>測試)
[2013/02/14 15:58:33.561314,  3, pid=9621, effective(0, 100), real(0, 0)] ../lib/util/charset/convert_string.c:316(convert_string_handle)

Hope this can help.

Kinglok, Fong