DDF: ddf_activate_spare: fix gcc -O2 uninitialized warning

At this point 'di' and 'rv' both have the same value.  gcc doesn't
realise that and a human reader might not either.
'rv' makes more sense too, so use that.

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

Have mdadm -E --export print the number of RAID devices,
like other meta data formats do. Anaconda (RHEL/CentOS installer)
depends on it.

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>
DDF: container_content_ddf: set safe_mode_delay > 0

Set safe_mode_delay to something >0, otherwise all container subarrays
assembled will have safe_mode_delay=0. That will break the assumption that
meta data becomes clean after running mdadm --wait-clean.

Use the same value as in getinfo_super_ddf_bvd. It would be cleaner
to call that directly from container_content_ddf, but I need to check
possible side effects first.

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>
DDF: increase default value for safe_mode_delay to 4000ms

That is the same value that IMSM uses. The current default of 200ms
seems to have been copied from the native MD meta data. That value
appears to be much too low for DDF, given that writing the DDF meta
data means that easily several MB worth of data need to be written to
disk.

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>
in_initrd: fix gcc compiler error

On some systems, this code caused a "comparison between signed
and unsigned" error.

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