[PATCH libaio 22/28] harness: Add fallback code for filesystems not supporting O_DIRECT

[PATCH libaio 22/28] harness: Add fallback code for filesystems not supporting O_DIRECT

When running the harness on a filesystem such as a tmpfs, which do not
support O_DIRECT, fallback to calls without the flag.

Signed-off-by: Guillem Jover <guillem@hadrons.org>
[JEM: change from duplicating the open call to using F_SETFL]
[JEM: 18 and 21 require O_DIRECT-skip if not present]
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Gbp-Pq: Topic upstream
Gbp-Pq: Name 0022-harness-Add-fallback-code-for-filesystems-not-suppor.patch