dm snapshot: move status to exception store

Let the exception store types print out their status through
the new API, rather than having the snapshot code do it.

Adjust the buffer position to allow for the preceding DMEMIT in the
arguments to type->status().

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-snap.c

@@ -70,9 +70,6 @@ struct dm_snapshot {
 	/* Origin writes don't trigger exceptions until this is set */
 	int active;
 
-	/* Used for display of table */
-	char type;
-
 	mempool_t *pending_pool;
 
 	atomic_t pending_exceptions_count;
@@ -1166,9 +1163,8 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
 		 * make sense.
 		 */
 		DMEMIT("%s", snap->origin->name);
-		DMEMIT(" %s %s %llu", snap->store->cow->name,
-		       snap->store->type->name,
-		       (unsigned long long)snap->store->chunk_size);
+		snap->store->type->status(snap->store, type, result + sz,
+					  maxlen - sz);
 		break;
 	}