problem related to Samba server
 

I have shared a directory AmitShare with read-write permission using smb
My smb.conf is-
[global]
workgroup = workgroup
netbios name = smbserver
security = user
load printers = No
default service = global
path = /home
available = No
encrypt passwords = yes
server string =
guest ok = yes
guest account = samit
; workgroup = workgroup
username map = /etc/samba/smbusers
; encrypt passwords = yes
[share]
writeable = yes
admin users = samit,amitabh
path = /home/AmitShare
; force user = root
available = yes
browseable = yes
valid users = amitabh, samit

Now please tell me that what should I do so that file added by one smb user can not be deleted by another smb user

What are the permissions on the /home/AmitShare directory? If both amitabh and samit can write to it, then set the sticky bit. This is what is done for the /tmp directory, and what the Samba documentation (Samba 3 by Example) says to do for directories for world writable shares.

If you are user "amit" and want to prevent "samit" from overwriting or editing it, then change the permissions of the file itself clearing the group and other write flags.