block_map.read_ops	# of block map reads
block_map.write_ops	# of block map writes
block_map.unmap	# of block delete operations
block_map.add_exlist 	# of extent list insertions for files
block_map.del_exlist	# of extent list deletions
block_map.look_exlist	# of extent list lookups
block_map.cmp_exlist	# of extent list compares
bmap_btree.lookup	# of block map btree lookups
bmap_btree.compare	# of block map compares
bmap_btree.insrec	# of block map insertions
bmap_btree.delrec	# of block map deletions