simplebench/bench-backup: add --compressed option

Allow bench compressed backup.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

scripts/simplebench/bench_block_job.py

@@ -21,6 +21,7 @@
 
 import sys
 import os
+import subprocess
 import socket
 import json
 
@@ -77,11 +78,29 @@ def bench_block_job(cmd, cmd_args, qemu_args):
     return {'seconds': (end_ms - start_ms) / 1000000.0}
 
 
+def get_image_size(path):
+    out = subprocess.run(['qemu-img', 'info', '--out=json', path],
+                         stdout=subprocess.PIPE, check=True).stdout
+    return json.loads(out)['virtual-size']
+
+
 # Bench backup or mirror
 def bench_block_copy(qemu_binary, cmd, cmd_options, source, target):
     """Helper to run bench_block_job() for mirror or backup"""
     assert cmd in ('blockdev-backup', 'blockdev-mirror')
 
+    if target['driver'] == 'qcow2':
+        try:
+            os.remove(target['file']['filename'])
+        except OSError:
+            pass
+
+        subprocess.run(['qemu-img', 'create', '-f', 'qcow2',
+                        target['file']['filename'],
+                        str(get_image_size(source['filename']))],
+                       stdout=subprocess.DEVNULL,
+                       stderr=subprocess.DEVNULL, check=True)
+
     source['node-name'] = 'source'
     target['node-name'] = 'target'
 
@@ -106,6 +125,10 @@ def drv_nbd(host, port):
             'server': {'type': 'inet', 'host': host, 'port': port}}
 
 
+def drv_qcow2(file):
+    return {'driver': 'qcow2', 'file': file}
+
+
 if __name__ == '__main__':
     import sys