---
 lib/metadata/lv_manip.c          |    1 +
 lib/metadata/metadata-exported.h |    3 +++
 lib/metadata/snapshot_manip.c    |   10 ++++++++--
 tools/lvcreate.c                 |    5 +++++
 4 files changed, 17 insertions(+), 2 deletions(-)

Index: LVM2.2.02.45/lib/metadata/lv_manip.c
===================================================================
--- LVM2.2.02.45.orig/lib/metadata/lv_manip.c	2009-05-19 21:13:23.000000000 +0200
+++ LVM2.2.02.45/lib/metadata/lv_manip.c	2009-05-19 21:13:31.000000000 +0200
@@ -1825,6 +1825,7 @@ void lv_init(struct logical_volume *lv)
 {
 	lv->snapshot = NULL;
 	lv->merging_snapshot = NULL;
+	lv->shared_snapshot = NULL;
 	dm_list_init(&lv->snapshot_segs);
 	dm_list_init(&lv->segments);
 	dm_list_init(&lv->tags);
Index: LVM2.2.02.45/lib/metadata/metadata-exported.h
===================================================================
--- LVM2.2.02.45.orig/lib/metadata/metadata-exported.h	2009-05-19 21:13:23.000000000 +0200
+++ LVM2.2.02.45/lib/metadata/metadata-exported.h	2009-05-19 21:13:31.000000000 +0200
@@ -339,6 +339,9 @@ struct logical_volume {
 	/* A snapshot that is merging into this origin */
 	struct lv_segment *merging_snapshot;
 
+	/* A shared-snapshot segment for this origin */
+	struct lv_segment *shared_snapshot;
+
 	struct dm_list segments;
 	struct dm_list tags;
 	struct dm_list segs_using_this_lv;
Index: LVM2.2.02.45/lib/metadata/snapshot_manip.c
===================================================================
--- LVM2.2.02.45.orig/lib/metadata/snapshot_manip.c	2009-05-19 21:13:23.000000000 +0200
+++ LVM2.2.02.45/lib/metadata/snapshot_manip.c	2009-05-19 21:13:31.000000000 +0200
@@ -77,8 +77,9 @@ int vg_add_snapshot(const char *name, st
 		return 0;
 	}
 
-	if (cow->status & SNAPSHOT_MERGE && origin->merging_snapshot) {
-		log_error("Origin has already merging snapshot.");
+	if (cow->status & (SNAPSHOT_MERGE | SNAPSHOT_SHARED) &&
+	    (origin->merging_snapshot || origin->shared_snapshot)) {
+		log_error("Origin has already merging or shared snapshot.");
 		return 0;
 	}
 
@@ -98,6 +99,8 @@ int vg_add_snapshot(const char *name, st
 	seg->lv->status |= SNAPSHOT;
 	if (snapshot_flags & SNAPSHOT_MERGE)
 		origin->merging_snapshot = seg;
+	if (snapshot_flags & SNAPSHOT_SHARED)
+		origin->shared_snapshot = seg;
 	seg->status |= snapshot_flags &
 		(SNAPSHOT_MERGE | SNAPSHOT_MERGE_ON_ACT | SNAPSHOT_SHARED);
 
@@ -120,6 +123,9 @@ int vg_remove_snapshot(struct logical_vo
 	if (cow->snapshot->origin->merging_snapshot == cow->snapshot)
 		cow->snapshot->origin->merging_snapshot = NULL;
 
+	if (cow->snapshot->origin->shared_snapshot == cow->snapshot)
+		cow->snapshot->origin->shared_snapshot = NULL;
+
 	if (!lv_remove(cow->snapshot->lv)) {
 		log_error("Failed to remove internal snapshot LV %s",
 			  cow->snapshot->lv->name);
Index: LVM2.2.02.45/tools/lvcreate.c
===================================================================
--- LVM2.2.02.45.orig/tools/lvcreate.c	2009-05-19 21:13:23.000000000 +0200
+++ LVM2.2.02.45/tools/lvcreate.c	2009-05-19 21:13:31.000000000 +0200
@@ -676,6 +676,11 @@ static int _lvcreate(struct cmd_context 
 				  "another snapshot is merging");
 			return 0;
 		}
+		if (org->shared_snapshot) {
+			log_error("It is not allowed to create more shared "
+				  "snapshot stores");
+			return 0;
+		}
 		if (org->status & MIRROR_IMAGE ||
 		    org->status & MIRROR_LOG ||
 		    org->status & MIRRORED) {