iotests: Make 137 work with data_file

When using an external data file, there are no refcounts for data
clusters.  We thus have to adjust the corruption test in this patch to
not be based around a data cluster allocation, but the L2 table
allocation (L2 tables are still refcounted with external data files).

Furthermore, we should not print qcow2.py's list of incompatible
features because it differs depending on whether there is an external
data file or not.

With those two changes, the test will work both with and without
external data files (once that options works with the iotests at all).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-id: 20191107163708.833192-20-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

tests/qemu-iotests/137

@@ -138,14 +138,21 @@ $QEMU_IO \
     "$TEST_IMG" 2>&1 | _filter_qemu_io
 
 # The dirty bit must not be set
-$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
+# (Filter the external data file bit)
+if $PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features \
+    | grep -q '\<0\>'
+then
+    echo 'ERROR: Dirty bit set'
+else
+    echo 'OK: Dirty bit not set'
+fi
 
 # Similarly we can test whether corruption detection has been enabled:
-# Create L1/L2, overwrite first entry in refcount block, allocate something.
+# Create L1, overwrite refcounts, force allocation of L2 by writing
+# data.
 # Disabling the checks should fail, so the corruption must be detected.
 _make_test_img 64M
-$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
-poke_file "$TEST_IMG" "$((0x20000))" "\x00\x00"
+poke_file "$TEST_IMG" "$((0x20000))" "\x00\x00\x00\x00\x00\x00\x00\x00"
 $QEMU_IO \
     -c "reopen -o overlap-check=none,lazy-refcounts=42" \
     -c "write 64k 64k" \

tests/qemu-iotests/137.out

@@ -36,11 +36,9 @@ qemu-io: Unsupported value 'blubb' for qcow2 option 'overlap-check'. Allowed are
 wrote 512/512 bytes at offset 0
 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 ./common.rc: Killed                  ( VALGRIND_QEMU="${VALGRIND_QEMU_IO}" _qemu_proc_exec "${VALGRIND_LOGFILE}" "$QEMU_IO_PROG" $QEMU_IO_ARGS "$@" )
-incompatible_features     []
+OK: Dirty bit not set
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
-wrote 65536/65536 bytes at offset 0
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 qemu-io: Parameter 'lazy-refcounts' expects 'on' or 'off'
-qcow2: Marking image as corrupt: Preventing invalid write on metadata (overlaps with qcow2_header); further corruption events will be suppressed
+qcow2: Marking image as corrupt: Preventing invalid allocation of L2 table at offset 0; further corruption events will be suppressed
 write failed: Input/output error
 *** done