What evaluates file perms when ACL's are involved?

[Michael Lueck]

Technology:
ReiserFS or XFS which support ACL's
Set an ACL on a directory before files are imported from tape, including a default ACL
Samba shares w/ "inherit acls = yes"

With Windows clients accessing these files via Samba in a Samba PDC environment, does Samba look to the filesystem / kernel to evaluate the ACL's, or is it involved in the process directly?

Is there a logic flowchart somewhere for how Linux evaluates traditional file permissions PLUS having ACL's tossed in to the mix. Seems like lots of options, and hard to begin to guess how it might 
all calculate out in the end. Basically looking to be able to upon seeing perms / ACL's arrive at the effective rights to an object.

I am involved as of 4:45 last evening in assisting with a "Help, 11th hour to putting Samba in production and we have file access issues!!!" been there before, just had not had ACL's in the mix. I 
guess this implementation of Linux is big enough news that it is written up by Novell. Some issues were resolved by getting to the 3.0.21c build today, perms and ACL do behave better there than with 
3.0.20b which they had on one server. But I am still looking to understand perms + ACL at a PhD level... leave no room for "maybe".

TIA!

-- 
Michael Lueck
Lueck Data Systems
http://www.lueckdatasystems.com/

Remove the upper case letters NOSPAM to contact me directly.