parallels: invent parallels_opts_prealloc() helper to parse prealloc opts

This patch creates above mentioned helper and moves its usage to the
beginning of parallels_open(). This simplifies parallels_open() a bit.

The patch also ensures that we store prealloc_size on block driver state
always in sectors. This makes code cleaner and avoids wrong opinion at
the assignment that the value is in bytes.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
1 file changed