From 21a17f291c8e69f5b7b2835fdedad1dc3945c59d Mon Sep 17 00:00:00 2001
From: Petr Rockai <prokai@redhat.com>
Date: Wed, 13 Oct 2010 13:52:53 +0000
Subject: [PATCH] Give correct error message when creating a too-small snapshot
 (BZ 587063)

---
 lib/metadata/lv_manip.c       |  5 +++++
 test/t-lvcreate-small-snap.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 test/t-lvcreate-small-snap.sh

diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 2bcfcc7e9..5044376eb 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -3123,6 +3123,11 @@ int lv_create_single(struct volume_group *vg,
 		return 0;
 	}
 
+	if (lp->snapshot && (lp->extents * vg->extent_size < 2 * lp->chunk_size)) {
+		log_error("Unable to create a snapshot smaller than 2 chunks.");
+		return 0;
+	}
+
 	if (!seg_is_virtual(lp) &&
 	    vg->free_count < lp->extents) {
 		log_error("Insufficient free extents (%u) in volume group %s: "
diff --git a/test/t-lvcreate-small-snap.sh b/test/t-lvcreate-small-snap.sh
new file mode 100644
index 000000000..789c09981
--- /dev/null
+++ b/test/t-lvcreate-small-snap.sh
@@ -0,0 +1,30 @@
+#!/bin/bash
+# Copyright (C) 2010 Red Hat, Inc. All rights reserved.
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions
+# of the GNU General Public License v.2.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+. ./test-utils.sh
+
+aux prepare_pvs 3
+
+vgcreate -c n -s 1k $vg $devs
+
+lvcreate -n one -l 10 $vg
+lvcreate -s -l 8 -n snapA $vg/one
+lvcreate -s -c 4k -l 8 -n snapX1 $vg/one
+lvcreate -s -c 8k -l 16 -n snapX2 $vg/one
+
+# Check that snapshots that are too small are caught with correct error.
+not lvcreate -s -c 8k -l 8 -n snapX3 $vg/one 2>&1 | tee lvcreate.out
+not grep "suspend origin one" lvcreate.out
+grep "Unable to create a snapshot" lvcreate.out
+
+not lvcreate -s -l 4 -n snapB $vg/one 2>&1 | tee lvcreate.out
+not grep "suspend origin one" lvcreate.out
+grep "Unable to create a snapshot" lvcreate.out
-- 
2.43.5