bug#13298: 24.3.50; Cannot write backup file; backing up in ~\.emacs.d\%backup%~

[Eli Zaretskii]

> Date: Sat, 29 Dec 2012 17:42:55 +0400
> From: Dmitry Gutov <dgutov@yandex.ru>
> CC: 13298@debbugs.gnu.org
> 
> > Can you step with a debugger (e.g., Edebug) through
> > backup-buffer-copy, and see why it errors out?  My crystal ball says
> > it happens because of set-file-extended-attributes, in which case
> > please tell what is the value of extended-attributes argument passed
> > to backup-buffer-copy.
> 
> Indeed, it happens after a call to set-file-acl.
> 
> ((acl . 
> "O:BAG:S-1-5-21-909999172-181315677-756075521-513D:(A;;FA;;;SY)(A;;FA;;;BA)(A;;FA;;;S-1-5-21-909999172-181315677-756075521-1000)")
>  
> (selinux-context nil nil nil nil))

And if, before the call to set-file-acl inside
set-file-extended-attributes, you evaluate the expression

  (file-acl filename)

what does it return?