Fix allocation code to allow replacement of single RAID 4/5/6 device.

The code fail to account for the case where we just need a single device
in a RAID 4/5/6 array.  There is no good way to tell the allocation functions
that we don't need parity devices when we are allocating just a single device.
So, I've used a bit of a hack.  If we are allocating an area_count that is <=
the parity count, then we can assume we are simply allocating a replacement
device (i.e. no need to include parity devices in the calculations).  This
should make sense in most cases.  If we need to allocate replacement devices
due to failure (or moving), we will never allocate more than the parity count;
or we would cause the array to become unusable.  If we are creating a new device,
we should always create more stripes than parity devices.

0 files changed, 0 insertions, 0 deletions