Ceph

Once we have OSDMap information we need to check for splits during pg import:

Sam:
Upon import, if we detect a split, we can simply filter out any
objects which would have been split out of the pg (perhaps we let the
user choose which child pg to import?). There is a [s]pg_t::is_split
method which tells you given two maps whether the pg corresponding to
that spg_t split between the two maps, and which child pgs it splits
into (osd_types.h).