The PE_PRESENT flags is always set for pagemap entries that have
corresponding pages in the pages*img. Pagemap entries describing a hole
either with zero page or with pages in the parent snapshot will no have
PE_PRESENT flag set.
Pagemap entry that may be lazily restored is a special case. For the lazy
restore from disk case, both PE_LAZY and PE_PRESENT will be set in the
pagemap, but for the remote lazy pages case only PE_LAZY will be set.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>