Handle activation errors.

With shared snapshot store it may happen that the store couldn't activate
itself if the user specifies invalid parameters for a given exception store
type. In this case, libdm would left orphan -real and -cow devices that would
cause trouble in further activities. Use suspend_lv+resume_lv trick to get
rid of these devices.

On activation failure, delete the snapshot volume.

Another problem is creating a shared snapshot of inactive volume. We activate
the volume just for a little moment to make sure that the parameters are
acceptable to the kernel.

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

---
 lib/metadata/lv_manip.c |   28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

Index: LVM2.2.02.85/lib/metadata/lv_manip.c
===================================================================
--- LVM2.2.02.85.orig/lib/metadata/lv_manip.c	2011-05-23 15:59:30.000000000 +0200
+++ LVM2.2.02.85/lib/metadata/lv_manip.c	2011-05-23 15:59:33.000000000 +0200
@@ -3799,9 +3799,32 @@ int lv_create_single(struct volume_group
 		if (!vg_write(vg))
 			return_0;
 
+		/*
+		 * The kernel has authority over parameters line validity.
+		 * To make sure that we won't commit invalid parameters
+		 * to the metadata, try to activate the origin.
+		 * We deactivate it later.
+		 */
+		if (!origin_active && lp->shared_store)
+			if (!activate_lv_excl(cmd, org))
+				goto snapshot_failure;
+
 		if (!suspend_lv(cmd, org)) {
-			log_error("Failed to suspend origin %s", org->name);
+snapshot_failure:
+			log_error("Failed to load snapshot driver for %s", lv->name);
 			vg_revert(vg);
+			lv_remove_with_dependencies(cmd, lv, 1, 0);
+
+			/*
+			 * This suspend+resume will clean up left
+			 * -real and -cow devices.
+			 */
+			if (!origin_active)
+				deactivate_lv(cmd, org);
+			else {
+				suspend_lv(cmd, org);
+				resume_lv(cmd, org);
+			}
 			return 0;
 		}
 
@@ -3812,6 +3835,9 @@ int lv_create_single(struct volume_group
 			log_error("Problem reactivating origin %s", org->name);
 			return 0;
 		}
+
+		if (!origin_active && lp->shared_store)
+			deactivate_lv(cmd, org);
 	}
 	/* FIXME out of sequence */
 	backup(vg);