Re: [PATCH 2/2] qemu-img: Require -F with -b backing image

@@ -17,7 +14,7 @@ qemu-io: can't open device TEST_DIR/t.qcow2: Could not open backing file: Unknow no file open, try 'help open' read 4096/4096 bytes at offset 0 4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) -qemu-img: warning: Deprecated use of backing file without explicit backing format, use of this image requires potentially unsafe format probing +qemu-img: Could not change the backing file to '/home/eblake/qemu/build/tests/qemu-iotests/scratch/t.qcow2.base': Invalid argument read 4096/4096 bytes at offset 0 4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)