diff --git a/block/qcow.c b/block/qcow.c
index ee5d35fe20ed..e91aa2d8c4d0 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -940,11 +940,12 @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,
 {
     BlockdevCreateOptions *create_options = NULL;
     BlockDriverState *bs = NULL;
-    QDict *qdict;
+    QDict *qdict = NULL;
     Visitor *v;
     const char *val;
     Error *local_err = NULL;
     int ret;
+    char *backing_fmt;

     static const QDictRenames opt_renames[] = {
         { BLOCK_OPT_BACKING_FILE,       "backing-file" },
@@ -952,6 +953,17 @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,
         { NULL, NULL },
     };

+    /*
+     * We can't actually store a backing format, but can check that
+     * the user's request made sense.
+     */
+    backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
+    if (backing_fmt && !bdrv_find_format(backing_fmt)) {
+        error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
+        ret = -EINVAL;
+        goto fail;
+    }
+
     /* Parse options and convert legacy syntax */
     qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);

@@ -1018,6 +1030,7 @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,

     ret = 0;
 fail:
+    g_free(backing_fmt);
     qobject_unref(qdict);
     bdrv_unref(bs);
     qapi_free_BlockdevCreateOptions(create_options);
@@ -1152,6 +1165,11 @@ static QemuOptsList qcow_create_opts = {
             .type = QEMU_OPT_STRING,
             .help = "File name of a base image"
         },
+        {
+            .name = BLOCK_OPT_BACKING_FMT,
+            .type = QEMU_OPT_STRING,
+            .help = "Format of the backing image",
+        },
         {
             .name = BLOCK_OPT_ENCRYPT,
             .type = QEMU_OPT_BOOL,
diff --git a/tests/qemu-iotests/293 b/tests/qemu-iotests/293
new file mode 100755
index 000000000000..3823e956175a
--- /dev/null
+++ b/tests/qemu-iotests/293
@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+#
+# Test qcow backing file warnings
+#
+# Copyright (C) 2020 Red Hat, Inc.
+#
+# 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/>.
+#
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+status=1 # failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+    _rm_test_img "$TEST_IMG.qcow2"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow
+_supported_proto file
+_supported_os Linux
+
+size=32M
+
+echo
+echo "== qcow backed by qcow =="
+
+TEST_IMG="$TEST_IMG.base" _make_test_img $size
+_make_test_img -b "$TEST_IMG.base" $size
+_img_info
+_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $size
+_img_info
+
+echo
+echo "== mismatched command line detection =="
+
+_make_test_img -b "$TEST_IMG.base" -F vmdk
+_make_test_img -b "$TEST_IMG.base" -F vmdk $size
+echo
+# Use of -u bypasses the backing format sanity check
+_make_test_img -u -b "$TEST_IMG.base" -F vmdk
+_make_test_img -u -b "$TEST_IMG.base" -F vmdk $size
+echo
+# But the format must still be recognized
+_make_test_img -b "$TEST_IMG.base" -F garbage $size
+_make_test_img -u -b "$TEST_IMG.base" -F garbage $size
+_img_info
+
+echo
+echo "== qcow backed by raw =="
+
+rm "$TEST_IMG.base"
+truncate --size=$size "$TEST_IMG.base"
+_make_test_img -b "$TEST_IMG.base" $size
+_img_info
+_make_test_img -b "$TEST_IMG.base" -F raw $size
+_img_info
+
+echo
+echo "== commit cannot change type of raw backing file =="
+TEST_IMG="$TEST_IMG.qcow2" IMGFMT=qcow2 _make_test_img $size
+truncate --size=$size "$TEST_IMG.qcow2"
+$QEMU_IMG convert -n -f raw -O $IMGFMT "$TEST_IMG.qcow2" "$TEST_IMG"
+$QEMU_IMG commit -f $IMGFMT "$TEST_IMG" && echo "unexpected success"
+TEST_IMG="$TEST_IMG.base" _img_info
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/293.out b/tests/qemu-iotests/293.out
new file mode 100644
index 000000000000..d07918b6d74b
--- /dev/null
+++ b/tests/qemu-iotests/293.out
@@ -0,0 +1,60 @@
+QA output created by 293
+
+== qcow backed by qcow ==
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=33554432
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base
+image: TEST_DIR/t.IMGFMT
+file format: IMGFMT
+virtual size: 32 MiB (33554432 bytes)
+cluster_size: 512
+backing file: TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
+image: TEST_DIR/t.IMGFMT
+file format: IMGFMT
+virtual size: 32 MiB (33554432 bytes)
+cluster_size: 512
+backing file: TEST_DIR/t.IMGFMT.base
+
+== mismatched command line detection ==
+qemu-img: TEST_DIR/t.IMGFMT: invalid VMDK image descriptor
+Could not open backing image to determine size.
+qemu-img: warning: Could not verify backing image. This may become an error in future versions.
+invalid VMDK image descriptor
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=vmdk
+
+qemu-img: TEST_DIR/t.IMGFMT: Image creation needs a size parameter
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=vmdk
+
+qemu-img: warning: Could not verify backing image. This may become an error in future versions.
+Unknown driver 'garbage'
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=garbage
+qemu-img: TEST_DIR/t.IMGFMT: unrecognized backing format 'garbage'
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=garbage
+qemu-img: TEST_DIR/t.IMGFMT: unrecognized backing format 'garbage'
+image: TEST_DIR/t.IMGFMT
+file format: IMGFMT
+virtual size: 32 MiB (33554432 bytes)
+cluster_size: 512
+backing file: TEST_DIR/t.IMGFMT.base
+
+== qcow backed by raw ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base
+image: TEST_DIR/t.IMGFMT
+file format: IMGFMT
+virtual size: 32 MiB (33554432 bytes)
+cluster_size: 512
+backing file: TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=raw
+image: TEST_DIR/t.IMGFMT
+file format: IMGFMT
+virtual size: 32 MiB (33554432 bytes)
+cluster_size: 512
+backing file: TEST_DIR/t.IMGFMT.base
+
+== commit cannot change type of raw backing file ==
+Formatting 'TEST_DIR/t.qcow.IMGFMT', fmt=IMGFMT size=33554432
+qemu-img: Block job failed: Operation not permitted
+image: TEST_DIR/t.IMGFMT.base
+file format: raw
+virtual size: 32 MiB (33554432 bytes)
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index d886fa0cb355..0dcfffdcad4a 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -301,4 +301,5 @@
 290 rw auto quick
 291 rw quick
 292 rw auto quick
+293 backing quick
 297 meta
