Implement a shared store target in libdevmapper.

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

---
 libdm/.exported_symbols |    1 
 libdm/libdevmapper.h    |    6 +++++
 libdm/libdm-deptree.c   |   50 ++++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 49 insertions(+), 8 deletions(-)

Index: LVM2.2.02.53/libdm/.exported_symbols
===================================================================
--- LVM2.2.02.53.orig/libdm/.exported_symbols	2009-10-13 02:32:41.000000000 +0200
+++ LVM2.2.02.53/libdm/.exported_symbols	2009-10-13 02:32:43.000000000 +0200
@@ -68,6 +68,7 @@ dm_tree_suspend_children
 dm_tree_children_use_uuid
 dm_tree_node_add_snapshot_origin_target
 dm_tree_node_add_snapshot_target
+dm_tree_node_add_snapshot_shared_target
 dm_tree_node_add_error_target
 dm_tree_node_add_zero_target
 dm_tree_node_add_linear_target
Index: LVM2.2.02.53/libdm/libdevmapper.h
===================================================================
--- LVM2.2.02.53.orig/libdm/libdevmapper.h	2009-10-13 02:32:41.000000000 +0200
+++ LVM2.2.02.53/libdm/libdevmapper.h	2009-10-13 02:32:43.000000000 +0200
@@ -382,6 +382,12 @@ int dm_tree_node_add_snapshot_target(str
 					const char *cow_uuid,
 					const char *exception_store,
 					uint32_t chunk_size);
+int dm_tree_node_add_snapshot_shared_target(struct dm_tree_node *node,
+					       uint64_t size,
+					       const char *origin_uuid,
+					       const char *cow_uuid,
+					       const char *exception_store,
+					       uint32_t chunk_size);
 int dm_tree_node_add_error_target(struct dm_tree_node *node,
 				     uint64_t size);
 int dm_tree_node_add_zero_target(struct dm_tree_node *node,
Index: LVM2.2.02.53/libdm/libdm-deptree.c
===================================================================
--- LVM2.2.02.53.orig/libdm/libdm-deptree.c	2009-10-13 02:32:41.000000000 +0200
+++ LVM2.2.02.53/libdm/libdm-deptree.c	2009-10-13 02:33:13.000000000 +0200
@@ -35,6 +35,7 @@ enum {
 	SEG_MIRRORED,
 	SEG_SNAPSHOT,
 	SEG_SNAPSHOT_ORIGIN,
+	SEG_SNAPSHOT_SHARED,
 	SEG_STRIPED,
 	SEG_ZERO,
 };
@@ -51,6 +52,7 @@ struct {
 	{ SEG_MIRRORED, "mirror" },
 	{ SEG_SNAPSHOT, "snapshot" },
 	{ SEG_SNAPSHOT_ORIGIN, "snapshot-origin" },
+	{ SEG_SNAPSHOT_SHARED, "multisnapshot" },
 	{ SEG_STRIPED, "striped" },
 	{ SEG_ZERO, "zero"},
 };
@@ -1437,6 +1439,14 @@ static int _emit_segment_line(struct dm_
 			return_0;
 		EMIT_PARAMS(pos, "%s", originbuf);
 		break;
+	case SEG_SNAPSHOT_SHARED:
+		if (!_build_dev_string(originbuf, sizeof(originbuf), seg->origin))
+			return_0;
+		if (!_build_dev_string(cowbuf, sizeof(cowbuf), seg->cow))
+			return_0;
+		EMIT_PARAMS(pos, "%s %s %d 0 %s 0", originbuf, cowbuf,
+			    seg->chunk_size, seg->exception_store);
+		break;
 	case SEG_STRIPED:
 		EMIT_PARAMS(pos, "%u %u ", seg->area_count, seg->stripe_size);
 		break;
@@ -1453,6 +1463,7 @@ static int _emit_segment_line(struct dm_
 	case SEG_ERROR:
 	case SEG_SNAPSHOT:
 	case SEG_SNAPSHOT_ORIGIN:
+	case SEG_SNAPSHOT_SHARED:
 	case SEG_ZERO:
 		break;
 	case SEG_CRYPT:
@@ -1718,17 +1729,18 @@ int dm_tree_node_add_snapshot_origin_tar
 	return 1;
 }
 
-int dm_tree_node_add_snapshot_target(struct dm_tree_node *node,
-                                        uint64_t size,
-                                        const char *origin_uuid,
-                                        const char *cow_uuid,
-                                        const char *exception_store,
-                                        uint32_t chunk_size)
+static int _add_snapshot_target(struct dm_tree_node *node,
+				   uint64_t size,
+				   const char *origin_uuid,
+				   const char *cow_uuid,
+				   int seg_type,
+				   const char *exception_store,
+				   uint32_t chunk_size)
 {
 	struct load_segment *seg;
 	struct dm_tree_node *origin_node, *cow_node;
 
-	if (!(seg = _add_segment(node, SEG_SNAPSHOT, size)))
+	if (!(seg = _add_segment(node, seg_type, size)))
 		return_0;
 
 	if (!(origin_node = dm_tree_find_node_by_uuid(node->dtree, origin_uuid))) {
@@ -1741,7 +1753,7 @@ int dm_tree_node_add_snapshot_target(str
 		return_0;
 
 	if (!(cow_node = dm_tree_find_node_by_uuid(node->dtree, cow_uuid))) {
-		log_error("Couldn't find snapshot origin uuid %s.", cow_uuid);
+		log_error("Couldn't find snapshot COW device uuid %s.", cow_uuid);
 		return 0;
 	}
 
@@ -1759,6 +1771,28 @@ int dm_tree_node_add_snapshot_target(str
 	return 1;
 }
 
+int dm_tree_node_add_snapshot_target(struct dm_tree_node *node,
+					uint64_t size,
+					const char *origin_uuid,
+					const char *cow_uuid,
+					const char *exception_store,
+					uint32_t chunk_size)
+{
+	return _add_snapshot_target(node, size, origin_uuid, cow_uuid,
+				    SEG_SNAPSHOT, exception_store, chunk_size);
+}
+
+int dm_tree_node_add_snapshot_shared_target(struct dm_tree_node *node,
+					       uint64_t size,
+					       const char *origin_uuid,
+					       const char *cow_uuid,
+					       const char *exception_store,
+					       uint32_t chunk_size)
+{
+	return _add_snapshot_target(node, size, origin_uuid, cow_uuid,
+			    SEG_SNAPSHOT_SHARED, exception_store, chunk_size);
+}
+
 int dm_tree_node_add_error_target(struct dm_tree_node *node,
                                      uint64_t size)
 {