iotests/026: Test EIO on allocation in a data-file

Test what happens when writing data to an external data file, where the
write requires an L2 entry to be allocated, but the data write fails.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200225143130.111267-4-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/026

@@ -30,6 +30,7 @@ _cleanup()
 {
 	_cleanup_test_img
     rm "$TEST_DIR/blkdebug.conf"
+    rm -f "$TEST_IMG.data_file"
 }
 trap "_cleanup; exit \$status" 0 1 2 3 15
 
@@ -239,6 +240,37 @@ $QEMU_IO -c "write 0 $CLUSTER_SIZE" "$BLKDBG_TEST_IMG" | _filter_qemu_io
 
 _check_test_img
 
+echo
+echo === Avoid freeing external data clusters on failure ===
+echo
+
+# Similar test as the last one, except we test what happens when there
+# is an error when writing to an external data file instead of when
+# writing to a preallocated zero cluster
+_make_test_img -o "data_file=$TEST_IMG.data_file" $CLUSTER_SIZE
+
+# Put blkdebug above the data-file, and a raw node on top of that so
+# that blkdebug will see a write_aio event and emit an error
+$QEMU_IO -c "write 0 $CLUSTER_SIZE" \
+    "json:{
+         'driver': 'qcow2',
+         'file': { 'driver': 'file', 'filename': '$TEST_IMG' },
+         'data-file': {
+             'driver': 'raw',
+             'file': {
+                 'driver': 'blkdebug',
+                 'config': '$TEST_DIR/blkdebug.conf',
+                 'image': {
+                     'driver': 'file',
+                     'filename': '$TEST_IMG.data_file'
+                 }
+             }
+         }
+     }" \
+    | _filter_qemu_io
+
+_check_test_img
+
 # success, all done
 echo "*** done"
 rm -f $seq.full

tests/qemu-iotests/026.out

@@ -653,4 +653,10 @@ wrote 1024/1024 bytes at offset 0
 1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 write failed: Input/output error
 No errors were found on the image.
+
+=== Avoid freeing external data clusters on failure ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1024 data_file=TEST_DIR/t.IMGFMT.data_file
+write failed: Input/output error
+No errors were found on the image.
 *** done

tests/qemu-iotests/026.out.nocache

@@ -661,4 +661,10 @@ wrote 1024/1024 bytes at offset 0
 1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 write failed: Input/output error
 No errors were found on the image.
+
+=== Avoid freeing external data clusters on failure ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1024 data_file=TEST_DIR/t.IMGFMT.data_file
+write failed: Input/output error
+No errors were found on the image.
 *** done