I have an Ext4 partition (not auto-mounted) that I would like to share (entirely) in my home that contains Mac OSX, Windows and Linux machines (currently the most important is sharing with the Mac). How may I do this?
Essentially, you will want to create a Samba share for the Ext4 mount point. Open-up your /etc/samba/smb.conf (in your favorite editor) and alter a few things:
1 - workgroup - you'll want to set that to the name of your network workgroup, if you have one.
2 - security = user - even if this line is commented-out, user-level security is the default for Samba.
3 - Define your Samba share at the bottom of the file. You should see a (commented-out) example at the bottom. You'll need the mount point of your ext4 partition (that you want to share). If you're not sure of what that is, do a "df -k" from terminal, and you should see it (put it in the "path" setting instead of "/some/directory").
4 - Next, you'll need to alter the permissions on the path (mount point) to ensure that the desired users can accomplish what they need to.
5 - Restart Samba
6 - Connect to your Samba share from your Mac. I found instructions on that here. Essentially, it says:
For me, I connect to my Samba shares by IP:
For troubleshooting, check the doc that I referenced: Mac OS X: How to connect to Windows File Sharing (SMB)
Hope this helps.
As an alternative to the venerable but complicated method of manually editing configuration files, unless you need to extensively customize who can access the share, you can simply:
As you can see, enabling guest access is as simple as checking the box for it.
This method works for sharing statically mounted volumes (like yours), dynamically mounted volumes, or any folder.