I have answered to the (two weeks old :-/) review. There are three open questions in there we'll have to figure out before I fix the patch:

- should copyxattr() remove xattrs in dst that aren't present in src? Make it an option like `remove_missing_xattr`?

- use "None" for `namespaces` in copyxattrs() to indicate we want to copy all of them?

- add a ignore_errors option?

ISTM, that "all namespaces" don't make much sense without ignore_errors as there seem to be some internal xattr etc. 

Suggestion: copyxattrs() has ignore_errors as default and returns a list of xattr it couldn't copy as (xattr, exception) tuples? Or an "on error" handler like in rmtree? I'd prefer the first one as ISTM that failures happen more often than not.