Create: fix warning about pre-existing filesystems.

An ext[234] filesystem larger than 2TB was beign reported with
a negative size - which looks odd.

So fix it to use suitably large and unsigned values.

Reported-by: Jan Engelhardt <jengelh@inai.de>
Signed-off-by: NeilBrown <neilb@suse.de>
tests/10ddf-fail-two-spares: new unit test

This is one more unit test for failure/recovery, this time with
double redundancy, which isn't covered by the other tests.

Signed-off-by: NeilBrown <neilb@suse.de>
tests/10ddf-fail-spare: more sophisticated result checks

This test can succeed two ways, depending on timing.

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>
tests/10ddf-fail-create-race: test handling of fail/create race

If a disk fails and simulaneously a new array is created, a race
condition may arise because the meta data on disk doesn't reflect
the disk failure yet. This is a test for that case.

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>
DDF: ddf_open_new: check device status for new subarray

It is possible that mdadm creates a new subarray containing failed
devices. This may happen if a device has failed, but the meta data
containing that information hasn't been written out yet.

This code tests for this situation, and handles it in the monitor.

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>