1 files changed, 45 insertions, 17 deletions

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 54853773510c..5974d3094d97 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -148,6 +148,12 @@ struct dm_snapshot {
 #define RUNNING_MERGE          0
 #define SHUTDOWN_MERGE         1
 
+struct dm_dev *dm_snap_origin(struct dm_snapshot *s)
+{
+	return s->origin;
+}
+EXPORT_SYMBOL(dm_snap_origin);
+
 struct dm_dev *dm_snap_cow(struct dm_snapshot *s)
 {
 	return s->cow;
@@ -1065,10 +1071,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		origin_mode = FMODE_WRITE;
 	}
 
-	origin_path = argv[0];
-	argv++;
-	argc--;
-
 	s = kmalloc(sizeof(*s), GFP_KERNEL);
 	if (!s) {
 		ti->error = "Cannot allocate snapshot context private "
@@ -1077,6 +1079,16 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
+	origin_path = argv[0];
+	argv++;
+	argc--;
+
+	r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
+	if (r) {
+		ti->error = "Cannot get origin device";
+		goto bad_origin;
+	}
+
 	cow_path = argv[0];
 	argv++;
 	argc--;
@@ -1097,12 +1109,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	argv += args_used;
 	argc -= args_used;
 
-	r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
-	if (r) {
-		ti->error = "Cannot get origin device";
-		goto bad_origin;
-	}
-
 	s->ti = ti;
 	s->valid = 1;
 	s->active = 0;
@@ -1212,15 +1218,15 @@ bad_kcopyd:
 	dm_exception_table_exit(&s->complete, exception_cache);
 
 bad_hash_tables:
-	dm_put_device(ti, s->origin);
-
-bad_origin:
 	dm_exception_store_destroy(s->store);
 
 bad_store:
 	dm_put_device(ti, s->cow);
 
 bad_cow:
+	dm_put_device(ti, s->origin);
+
+bad_origin:
 	kfree(s);
 
 bad:
@@ -1314,12 +1320,12 @@ static void snapshot_dtr(struct dm_target *ti)
 
 	mempool_destroy(s->pending_pool);
 
-	dm_put_device(ti, s->origin);
-
 	dm_exception_store_destroy(s->store);
 
 	dm_put_device(ti, s->cow);
 
+	dm_put_device(ti, s->origin);
+
 	kfree(s);
 }
 
@@ -1686,7 +1692,7 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio,
 	chunk_t chunk;
 
 	if (unlikely(bio_empty_barrier(bio))) {
-		if (!map_context->flush_request)
+		if (!map_context->target_request_nr)
 			bio->bi_bdev = s->origin->bdev;
 		else
 			bio->bi_bdev = s->cow->bdev;
@@ -1899,8 +1905,14 @@ static int snapshot_iterate_devices(struct dm_target *ti,
 				    iterate_devices_callout_fn fn, void *data)
 {
 	struct dm_snapshot *snap = ti->private;
+	int r;
+
+	r = fn(ti, snap->origin, 0, ti->len, data);
+
+	if (!r)
+		r = fn(ti, snap->cow, 0, get_dev_size(snap->cow->bdev), data);
 
-	return fn(ti, snap->origin, 0, ti->len, data);
+	return r;
 }
 
 
@@ -2159,6 +2171,21 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result,
 	return 0;
 }
 
+static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
+			struct bio_vec *biovec, int max_size)
+{
+	struct dm_dev *dev = ti->private;
+	struct request_queue *q = bdev_get_queue(dev->bdev);
+
+	if (!q->merge_bvec_fn)
+		return max_size;
+
+	bvm->bi_bdev = dev->bdev;
+	bvm->bi_sector = bvm->bi_sector;
+
+	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
+}
+
 static int origin_iterate_devices(struct dm_target *ti,
 				  iterate_devices_callout_fn fn, void *data)
 {
@@ -2176,6 +2203,7 @@ static struct target_type origin_target = {
 	.map     = origin_map,
 	.resume  = origin_resume,
 	.status  = origin_status,
+	.merge	 = origin_merge,
 	.iterate_devices = origin_iterate_devices,
 };