cache: allow deactivation of empty pool

Tool will use internal activation of unused cache pool to
clear metadata area before next use of cache-pool.
So allow to deactivation unused pool in case some error
case happend and we were not able to deactivation pool
right after metadata wipe.

3 files changed, 18 insertions, 8 deletions

diff --git a/tools/lvchange.c b/tools/lvchange.c
index 66979059e..99dba8292 100644
--- a/tools/lvchange.c
+++ b/tools/lvchange.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2011 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2014 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -170,9 +170,6 @@ static int _lvchange_activate(struct cmd_context *cmd, struct logical_volume *lv
 
 	activate = (activation_change_t) arg_uint_value(cmd, activate_ARG, CHANGE_AY);
 
-	if (lv_is_cache_pool(lv))
-		return 1;
-
 	if (lv_activation_skip(lv, activate, arg_count(cmd, ignoreactivationskip_ARG)))
 		return 1;
 
diff --git a/tools/toollib.c b/tools/toollib.c
index e87fd30c4..0472597c3 100644
--- a/tools/toollib.c
+++ b/tools/toollib.c
@@ -688,6 +688,23 @@ int lv_change_activate(struct cmd_context *cmd, struct logical_volume *lv,
 {
 	int r = 1;
 
+	if (lv_is_cache_pool(lv)) {
+		if (is_change_activating(activate)) {
+			log_verbose("Skipping activation of cache pool %s.",
+				    display_lvname(lv));
+			return 1;
+		}
+		if (!dm_list_empty(&lv->segs_using_this_lv)) {
+			log_verbose("Skipping deactivation of used cache pool %s.",
+				    display_lvname(lv));
+			return 1;
+		}
+		/*
+		 * Allow to pass only deactivation of unused cache pool.
+		 * Useful only for recovery of failed zeroing of metadata LV.
+		 */
+	}
+
 	if (lv_is_merging_origin(lv)) {
 		/*
 		 * For merging origin, its snapshot must be inactive.
diff --git a/tools/vgchange.c b/tools/vgchange.c
index af59f3a55..e5d700de8 100644
--- a/tools/vgchange.c
+++ b/tools/vgchange.c
@@ -97,10 +97,6 @@ static int _activate_lvs_in_vg(struct cmd_context *cmd, struct volume_group *vg,
 		if (!lv_is_visible(lv))
 			continue;
 
-		/* Cache pool cannot be activated */
-		if (lv_is_cache_pool(lv))
-			continue;
-
 		/* If LV is sparse, activate origin instead */
 		if (lv_is_cow(lv) && lv_is_virtual_origin(origin_from_cow(lv)))
 			lv = origin_from_cow(lv);