int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
dm_block_t end, dm_block_t *result);
+int sm_ll_find_common_free_block(struct ll_disk *old_ll, struct ll_disk *new_ll,
+ dm_block_t begin, dm_block_t end, dm_block_t *result);
int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev);
int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);