On Linux block devices used for vdevs will by partitioned. The block
device must be large enough for an 64M partition starting at offset
of 2048 sectors (part1), and a second 64M reserved partition at the
end of the device (part9).
This commit adds a capacity check when creating the GPT label to
immediately detect a device which is too small. With the existing
code this would be caught slightly latter when attempting to use
the partition. Catching it sooner let's us print a more useful error.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#15898