ovl: handle ENOENT on index lookup

ovl: handle ENOENT on index lookup

BugLink: http://bugs.launchpad.net/bugs/1731961
commit 7937a56fdf0b064c2ffa33025210f725a4ebc822 upstream.

Treat ENOENT from index entry lookup the same way as treating a returned
negative dentry. Apparently, either could be returned if file is not
found, depending on the underlying file system.

Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>