A function to find merging snapshot for a given origin device.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/md/dm-snap.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Index: linux-2.6.26-devel/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.26-devel.orig/drivers/md/dm-snap.c	2008-07-14 20:23:31.000000000 +0200
+++ linux-2.6.26-devel/drivers/md/dm-snap.c	2008-07-14 20:23:38.000000000 +0200
@@ -197,6 +197,22 @@ static struct origin *__lookup_origin(st
 	return NULL;
 }
 
+static struct dm_snapshot *__find_merging_snapshot(struct block_device *origin)
+{
+	struct origin *o;
+	struct dm_snapshot *snap;
+
+	o = __lookup_origin(origin);
+	if (!o)
+		return NULL;
+
+	list_for_each_entry (snap, &o->snapshots, list)
+		if (is_merge(snap->ti))
+			return snap;
+
+	return NULL;
+}
+
 static void __insert_origin(struct origin *o)
 {
 	struct list_head *sl = &_origins[origin_hash(o->bdev)];