K{Disk,File,Partitioning}System writing methods. It is now required
that the caller has marked the concerned partitions busy, hence we can
(read-)access them without needing a lock. The module interfaces will
will be changed to take advantage of the fact as well. The methods take a
disk_job_id instead of a KDiskDeviceJob* now, though I haven't quite
decided, whether we need it at all or just want to add a special
handling in the cases where notifications during the operation make
sense.
* Reimplemented the disk device write support syscalls (save
_user_move_partition() for which other module hooks are needed). They
call the KDiskSystem methods, now.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22832 a95241bf-73f2-0310-859d-f6bbb57e9c96