For parallels images extensions we need to allocate host clusters
without any connection to BAT. Move host clusters allocation code to
parallels_allocate_host_clusters().
This function can be called not only from coroutines so all the
*_co_* functions were replaced by corresponding wrappers.
Add parallels_mark_unused(), the helper releasing an area in the used
bitmap, as the new function needs it to undo an allocation.
The size of the request and the size of the area preallocated for it
live in two variables here, where the code being moved kept them in
one. The used bitmap has to grow by the latter, as it is what tells
the allocator how far the image reaches: counting only the requested
clusters hides the preallocated tail, so the next allocation starts
over at the end it knows about and preallocates the very same space
again.
data_end has to grow past an allocation which lands in the space
preallocated by an earlier one as well, not only past one which appends
to the image. The field marks the end of the payload for the truncation
on inactivation, so an allocation which leaves it behind is cut off the
image the moment the node is closed, and the data written into it is
lost.
Based on the original work from Alexander Ivanov.
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Denis V. Lunev
70615b7966