Introduce a SEG_NOEXPLICIT flag.

The flag means that the segment cannot be explicitly created with
lvcreate --type.

It is used on shared snapshots, to prevent a crash when the user uses
"multisnapshot" or "multisnap-snap" segment type.

I also added it to legacy snapshots, but it is not needed there
(the create routine already converts "snapshots" type to "striped").

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

---
 lib/metadata/lv_manip.c           |    5 +++++
 lib/metadata/segtype.h            |    1 +
 lib/multisnapshot/multisnapshot.c |    4 ++--
 lib/snapshot/snapshot.c           |    2 +-
 4 files changed, 9 insertions(+), 3 deletions(-)

Index: LVM2.2.02.85/lib/metadata/segtype.h
===================================================================
--- LVM2.2.02.85.orig/lib/metadata/segtype.h	2011-06-24 18:57:32.000000000 +0200
+++ LVM2.2.02.85/lib/metadata/segtype.h	2011-06-24 18:58:40.000000000 +0200
@@ -37,6 +37,7 @@ struct dev_manager;
 #define SEG_MONITORED		0x00000080U
 #define SEG_REPLICATOR		0x00000100U
 #define SEG_REPLICATOR_DEV	0x00000200U
+#define SEG_NOEXPLICIT		0x00000400U
 #define SEG_UNKNOWN		0x80000000U
 
 #define seg_is_mirrored(seg)	((seg)->segtype->flags & SEG_AREAS_MIRRORED ? 1 : 0)
Index: LVM2.2.02.85/lib/multisnapshot/multisnapshot.c
===================================================================
--- LVM2.2.02.85.orig/lib/multisnapshot/multisnapshot.c	2011-06-24 18:57:32.000000000 +0200
+++ LVM2.2.02.85/lib/multisnapshot/multisnapshot.c	2011-06-24 18:58:40.000000000 +0200
@@ -255,7 +255,7 @@ int init_multiple_segtypes(struct cmd_co
 	segtype->ops = &_multisnapshot_ops;
 	segtype->name = "multisnapshot";
 	segtype->private = NULL;
-	segtype->flags = SEG_SNAPSHOT;
+	segtype->flags = SEG_SNAPSHOT | SEG_NOEXPLICIT;
 
 	if (!lvm_register_segtype(lib, segtype))
 		return 0;
@@ -270,7 +270,7 @@ int init_multiple_segtypes(struct cmd_co
 	segtype->ops = &_multisnap_snap_ops;
 	segtype->name = "multisnap-snap";
 	segtype->private = NULL;
-	segtype->flags = SEG_VIRTUAL | SEG_CANNOT_BE_ZEROED;
+	segtype->flags = SEG_VIRTUAL | SEG_CANNOT_BE_ZEROED | SEG_NOEXPLICIT;
 
 	if (!lvm_register_segtype(lib, segtype))
 		return 0;
Index: LVM2.2.02.85/lib/snapshot/snapshot.c
===================================================================
--- LVM2.2.02.85.orig/lib/snapshot/snapshot.c	2011-06-24 18:57:32.000000000 +0200
+++ LVM2.2.02.85/lib/snapshot/snapshot.c	2011-06-24 18:58:40.000000000 +0200
@@ -256,7 +256,7 @@ struct segment_type *init_segtype(struct
 	segtype->ops = &_snapshot_ops;
 	segtype->name = "snapshot";
 	segtype->private = NULL;
-	segtype->flags = SEG_SNAPSHOT;
+	segtype->flags = SEG_SNAPSHOT | SEG_NOEXPLICIT;
 
 #ifdef DEVMAPPER_SUPPORT
 #  ifdef DMEVENTD
Index: LVM2.2.02.85/lib/metadata/lv_manip.c
===================================================================
--- LVM2.2.02.85.orig/lib/metadata/lv_manip.c	2011-06-24 18:58:37.000000000 +0200
+++ LVM2.2.02.85/lib/metadata/lv_manip.c	2011-06-24 18:58:40.000000000 +0200
@@ -3672,6 +3672,11 @@ again:
 			if (!(lp->segtype = get_segtype_from_string(cmd, "multisnap-snap")))
 				return_0;
 		}
+	} else {
+		if (lp->segtype->flags & SEG_NOEXPLICIT) {
+			log_error("This type of segment cannot be explicitly created");
+			return 0;
+		}
 	}
 
 	if (!lp->extents) {