I'm trying to work out the best way to mount a share which is accessible to both windows and linux and retains the correct permissions.

I looked into using pam_mount on linux which will allow CIFS/SMBFS shares.

I found the following issues with pam_mount tho:
• “su” to a user with a home directory on a share will fail to mount the home directory unless you know the user’s password. This would cause issues for cronjobs.
• ssh’ing into a server as a user with a home directory on a share will prompt for a password to mount the home directory even with passphraseless ssh keys. This would cause issues with any automated login scripts
• You can force the ownerships of the files/directories to be owned correctly from windows to linux, but they may not be correct the other way around.

Does anyone have any better solutions?

I have always done this using NFS for linux clients and samba for windows clients, with both systems using the same usernames. You can then combine NFS with autofs if necessary and samba takes care of windows access controls and creation groups etc.

Do you mean you're using 2 separate shares? 1 being for windows via SMBFS and the other NFS for linux?

I'm after a single share which can be mounted on both linux and windows - with the correct ownerships etc.

I have tried using a single share and having it shared out using NFS (for linux) and SMBFS (for windows). The issue here is that the ownerships don't match up properly.
i.e Create a file on the SMBFS share from windows and then mount the NFS on linux. You can see the UID of the file doesn't match up with the UID of teh same username on linux (the windows SID is being translated to a UID on the NAS differently to how the linux server is translating the SID->UID).

It has always been a problem. There was never a single share approach I found that was satisfactory. Theoretically it should work, but I never had the infrastructure at my disposal. All depends on kerberos really.

The NFS and Samba setup doesnt have direct UID mapping it's true, but the username mappings have always been sufficient for me.