lv_manip: ensure it will fit bellow threshold

Use single code to evaluate if the percentage value has
crossed threshold.

Recalculate amount value to always fit bellow
threshold so there are not need any extra reiterations
to reach this state in case policy amount is too small.

2 files changed, 26 insertions, 12 deletions

diff --git a/WHATS_NEW b/WHATS_NEW
index 0495e4683..8ca0aa7f5 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.133 - 
 ======================================
+  Ensure --use-policy will resize volume to fit below threshold.
   Correct percentage evaluation when checking thin-pool over threshold.
   Fix lvmcache to move PV from VG to orphans if VG is removed and lvmetad used.
   Fix lvmcache to not cache even invalid info about PV which got removed.
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 19032e9b2..8029dabf5 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -4424,6 +4424,25 @@ static int _fsadm_cmd(struct cmd_context *cmd,
 	return exec_cmd(cmd, argv, status, 1);
 }
 
+static int _adjust_amount(dm_percent_t percent, int policy_threshold, int *policy_amount)
+{
+	if (!(DM_PERCENT_0 < percent && percent <= DM_PERCENT_100) ||
+	    percent <= (policy_threshold * DM_PERCENT_1))
+		return 0;
+	/*
+	 * Evaluate the minimal amount needed to get bellow threshold.
+	 * Keep using DM_PERCENT_1 units for better precision.
+	 * Round-up to needed percentage value
+	 */
+	percent = (percent/policy_threshold + (DM_PERCENT_1 - 1) / 100) / (DM_PERCENT_1 / 100) - 100;
+
+	/* Use it if current policy amount is smaller */
+	if (*policy_amount < percent)
+		*policy_amount = percent;
+
+	return 1;
+}
+
 static int _adjust_policy_params(struct cmd_context *cmd,
 				 struct logical_volume *lv, struct lvresize_params *lp)
 {
@@ -4469,35 +4488,29 @@ static int _adjust_policy_params(struct cmd_context *cmd,
 		return 0;
 	}
 
-	policy_threshold *= DM_PERCENT_1;
-
 	if (lv_is_thin_pool(lv)) {
 		if (!lv_thin_pool_percent(lv, 1, &percent))
 			return_0;
-		if ((DM_PERCENT_0 < percent && percent <= DM_PERCENT_100) &&
-		    (percent > policy_threshold)) {
+		if (_adjust_amount(percent, policy_threshold, &policy_amount)) {
 			if (!thin_pool_feature_supported(lv, THIN_FEATURE_METADATA_RESIZE)) {
-				log_error_once("Online metadata resize for %s/%s is not supported.",
-					       lv->vg->name, lv->name);
+				log_error_once("Online metadata resize for %s is not supported.",
+					       display_lvname(lv));
 				return 0;
 			}
 			lp->poolmetadatasize = (first_seg(lv)->metadata_lv->size *
 						policy_amount + 99) / 100;
 			lp->poolmetadatasign = SIGN_PLUS;
 		}
-
 		if (!lv_thin_pool_percent(lv, 0, &percent))
 			return_0;
-		if (!(DM_PERCENT_0 < percent && percent <= DM_PERCENT_100) ||
-		    percent <= policy_threshold)
-			return 1;
 	} else {
 		if (!lv_snapshot_percent(lv, &percent))
 			return_0;
-		if (!(DM_PERCENT_0 < percent && percent <= DM_PERCENT_100) || percent <= policy_threshold)
-			return 1; /* nothing to do */
 	}
 
+	if (!_adjust_amount(percent, policy_threshold, &policy_amount))
+		return 1; /* nothing to do */
+
 	lp->extents = policy_amount;
 	lp->sizeargs = (lp->extents) ? 1 : 0;