diff --git a/block/qcow2.c b/block/qcow2.c
index 2ba0b17c39..8c97b06783 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4239,15 +4239,17 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
          * requires a cluster-aligned start. The end may be unaligned if it is
          * at the end of the image (which it is here).
          */
-        ret = qcow2_cluster_zeroize(bs, zero_start, offset - zero_start, 0);
-        if (ret < 0) {
-            error_setg_errno(errp, -ret, "Failed to zero out new clusters");
-            goto fail;
+        if (offset > zero_start) {
+            ret = qcow2_cluster_zeroize(bs, zero_start, offset - zero_start, 0);
+            if (ret < 0) {
+                error_setg_errno(errp, -ret, "Failed to zero out new clusters");
+                goto fail;
+            }
         }
 
         /* Write explicit zeros for the unaligned head */
         if (zero_start > old_length) {
-            uint64_t len = zero_start - old_length;
+            uint64_t len = MIN(zero_start, offset) - old_length;
             uint8_t *buf = qemu_blockalign0(bs, len);
             QEMUIOVector qiov;
             qemu_iovec_init_buf(&qiov, buf, len);
diff --git a/tests/qemu-iotests/292 b/tests/qemu-iotests/292
new file mode 100755
index 0000000000..a2de27cca4
--- /dev/null
+++ b/tests/qemu-iotests/292
@@ -0,0 +1,73 @@
+#!/usr/bin/env bash
+#
+# Test resizing a qcow2 image with a backing file
+#
+# Copyright (C) 2020 Igalia, S.L.
+# Author: Alberto Garcia <berto@igalia.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=berto@igalia.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+status=1    # failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+echo '### Create the backing image'
+BACKING_IMG="$TEST_IMG.base"
+TEST_IMG="$BACKING_IMG" _make_test_img 1M
+
+echo '### Fill the backing image with data (0x11)'
+$QEMU_IO -c 'write -P 0x11 0 1M' "$BACKING_IMG" | _filter_qemu_io
+
+echo '### Create the top image'
+_make_test_img -F "$IMGFMT" -b "$BACKING_IMG"
+
+echo '### Fill the top image with data (0x22)'
+$QEMU_IO -c 'write -P 0x22 0 1M' "$TEST_IMG" | _filter_qemu_io
+
+# Both offsets are part of the same cluster.
+echo '### Shrink the image to 520k'
+$QEMU_IMG resize --shrink "$TEST_IMG" 520k
+echo '### Grow the image to 567k'
+$QEMU_IMG resize "$TEST_IMG" 567k
+
+echo '### Check that the tail of the image reads as zeroes'
+$QEMU_IO -c 'read -P 0x22    0 520k' "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c 'read -P 0x00 520k  47k' "$TEST_IMG" | _filter_qemu_io
+
+echo '### Show output of qemu-img map'
+$QEMU_IMG map "$TEST_IMG" | _filter_testdir
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/292.out b/tests/qemu-iotests/292.out
new file mode 100644
index 0000000000..807e0530c3
--- /dev/null
+++ b/tests/qemu-iotests/292.out
@@ -0,0 +1,24 @@
+QA output created by 292
+### Create the backing image
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=1048576
+### Fill the backing image with data (0x11)
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+### Create the top image
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
+### Fill the top image with data (0x22)
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+### Shrink the image to 520k
+Image resized.
+### Grow the image to 567k
+Image resized.
+### Check that the tail of the image reads as zeroes
+read 532480/532480 bytes at offset 0
+520 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 48128/48128 bytes at offset 532480
+47 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+### Show output of qemu-img map
+Offset          Length          Mapped to       File
+0               0x8dc00         0x50000         TEST_DIR/t.qcow2
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 1710470e70..fe649c5b73 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -298,3 +298,4 @@
 288 quick
 289 rw quick
 290 rw auto quick
+292 rw auto quick
