diff --git a/block/io.c b/block/io.c
index 8b6dace056..f0b86c1d19 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2090,6 +2090,13 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
         return ret;
     }
 
+    /* If the request is misaligned then we can't make it efficient */
+    if ((flags & BDRV_REQ_NO_FALLBACK) &&
+        !QEMU_IS_ALIGNED(offset | bytes, align))
+    {
+        return -ENOTSUP;
+    }
+
     bdrv_inc_in_flight(bs);
     /*
      * Align write if necessary by performing a read-modify-write cycle.
diff --git a/tests/qemu-iotests/268 b/tests/qemu-iotests/268
new file mode 100755
index 0000000000..78c3f4db3a
--- /dev/null
+++ b/tests/qemu-iotests/268
@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+#
+# Test write request with required alignment larger than the cluster size
+#
+# Copyright (C) 2019 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 $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+
+echo
+echo "== Required alignment larger than cluster size =="
+
+CLUSTER_SIZE=2k _make_test_img 1M
+# Since commit c8bb23cbdb writing to an unallocated cluster fills the
+# empty COW areas with bdrv_write_zeroes(flags=BDRV_REQ_NO_FALLBACK)
+$QEMU_IO -c "open -o driver=$IMGFMT,file.align=4k blkdebug::$TEST_IMG" \
+         -c "write 0 512" | _filter_qemu_io
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/268.out b/tests/qemu-iotests/268.out
new file mode 100644
index 0000000000..2ed6c68529
--- /dev/null
+++ b/tests/qemu-iotests/268.out
@@ -0,0 +1,7 @@
+QA output created by 268
+
+== Required alignment larger than cluster size ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+wrote 512/512 bytes at offset 0
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 5805a79d9e..4c861f7eed 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -278,3 +278,4 @@
 265 rw auto quick
 266 rw quick
 267 rw auto quick snapshot
+268 rw auto quick