passdb backend 设置为 smbpasswd 时，无法访问samba服务器，设置为 tdbsam 则可以访问，遇到这个问题，纠结了好久，没有查找到原因，我的smb.conf内容如下：
#======================= Global Settings ============================
[global]
workgroup = workgroup
security = user
;server string = samba
;netbios name = samba
;encrypt passwords = yes
;passdb backend =tdbsam
passdb backend = smbpasswd
smb passwd file = /etc/samba/smbpasswd
;username map = /etc/samba/smbusers
#===================== Share Definitions ============================
[homes]
comment = Home Directories
path = /home
browseable = yes
writable = yes
valid users = %S
available = yes
[public]
comment = Public Stuff
path = /home/public
browseable = yes
read only = yes
guest ok = yes
available = yes
[Tom]
comment = Tom*s Stuff
path = /home/Tom/
writeable = yes
browseable = yes
available = yes
valid users = Tom