RE: [PATCH] ACL handling simplification + support for NFSv4

[Ondrej Valousek]

> What happens if you try to copy ACLs from a filesystem using NFSv4 ACLs to 
> one using POSIXish ACLs, or vice versa?
It fails, we can't do ACL conversion.

> Why is this call needed? Won't a successful attr_copy_file mean that the 
> chmod_or_fchmod is unnecessary? I.e., can't we do the chmod_or_lchmod only if 
> the attr_copy_file fails with a particular errno value that says "this file 
> lacks extended attributes"?
No. ACL only substitute the lower mode bits, we still need to copy the 
(possible) sticky bits. We also need to copy mode in case no ACL (i.e. no 
xattrs to copy) presented.

> When these functions fail, what are their errno values and should we treat 
> any of them specially? (I can't easily find documentation for these 
> functions.)
It returns -1, so it behaves the same way as the original function - we do not 
need to treat it differently.