XFS ACLs( How about a user belongs to multiple groups )

[<niu@xxxxxxxxxxxxxxxxxxxx>]

Hi XFS guys,

I'm using ACLs of linux XFS to manage my share files. Recently, I
encounter a confused problem: If a user belongs to multiple groups, and
all the groups are set ALCs to a file(directory), then how about the
user's permission to this file(directory)?

I've do some test, the result looks like that: for file, the user's
permission is the combination(OR operation) of his groups ACLs; but
for directory, the user's permission looks weird, it's neither OR
operation nor AND operation of his groups ACLs.

Could you explain more details about the rule of XFS ACLs? Thank you.

John