[PULL,53/56] iotests/image-fleecing: add test-case for copy-before-write filter

diff --git a/tests/qemu-iotests/tests/image-fleecing b/tests/qemu-iotests/tests/image-fleecing
index e210c00d28..f6318492c6 100755
--- a/tests/qemu-iotests/tests/image-fleecing
+++ b/tests/qemu-iotests/tests/image-fleecing
@@ -48,7 +48,7 @@  remainder = [('0xd5', '0x108000',  '32k'), # Right-end of partial-left [1]
              ('0xdc', '32M',       '32k'), # Left-end of partial-right [2]
              ('0xcd', '0x3ff0000', '64k')] # patterns[3]
 
-def do_test(base_img_path, fleece_img_path, nbd_sock_path, vm):
+def do_test(use_cbw, base_img_path, fleece_img_path, nbd_sock_path, vm):
     log('--- Setting up images ---')
     log('')
 
@@ -67,6 +67,7 @@  def do_test(base_img_path, fleece_img_path, nbd_sock_path, vm):
 
     src_node = 'source'
     tmp_node = 'temp'
+    qom_path = '/machine/peripheral/sda'
     vm.add_blockdev(f'driver={iotests.imgfmt},file.driver=file,'
                     f'file.filename={base_img_path},node-name={src_node}')
     vm.add_device('virtio-scsi')
@@ -90,12 +91,22 @@  def do_test(base_img_path, fleece_img_path, nbd_sock_path, vm):
         'backing': src_node,
     }))
 
-    # Establish COW from source to fleecing node
-    log(vm.qmp('blockdev-backup',
-               job_id='fleecing',
-               device=src_node,
-               target=tmp_node,
-               sync='none'))
+    # Establish CBW from source to fleecing node
+    if use_cbw:
+        log(vm.qmp('blockdev-add', {
+            'driver': 'copy-before-write',
+            'node-name': 'fl-cbw',
+            'file': src_node,
+            'target': tmp_node
+        }))
+
+        log(vm.qmp('qom-set', path=qom_path, property='drive', value='fl-cbw'))
+    else:
+        log(vm.qmp('blockdev-backup',
+                   job_id='fleecing',
+                   device=src_node,
+                   target=tmp_node,
+                   sync='none'))
 
     log('')
     log('--- Setting up NBD Export ---')
@@ -124,7 +135,7 @@  def do_test(base_img_path, fleece_img_path, nbd_sock_path, vm):
     for p in overwrite:
         cmd = 'write -P%s %s %s' % p
         log(cmd)
-        log(vm.hmp_qemu_io('/machine/peripheral/sda', cmd, qdev=True))
+        log(vm.hmp_qemu_io(qom_path, cmd, qdev=True))
 
     log('')
     log('--- Verifying Data ---')
@@ -139,10 +150,15 @@  def do_test(base_img_path, fleece_img_path, nbd_sock_path, vm):
     log('--- Cleanup ---')
     log('')
 
-    log(vm.qmp('block-job-cancel', device='fleecing'))
-    e = vm.event_wait('BLOCK_JOB_CANCELLED')
-    assert e is not None
-    log(e, filters=[iotests.filter_qmp_event])
+    if use_cbw:
+        log(vm.qmp('qom-set', path=qom_path, property='drive', value=src_node))
+        log(vm.qmp('blockdev-del', node_name='fl-cbw'))
+    else:
+        log(vm.qmp('block-job-cancel', device='fleecing'))
+        e = vm.event_wait('BLOCK_JOB_CANCELLED')
+        assert e is not None
+        log(e, filters=[iotests.filter_qmp_event])
+
     log(vm.qmp('nbd-server-stop'))
     log(vm.qmp('blockdev-del', node_name=tmp_node))
     vm.shutdown()
@@ -160,13 +176,17 @@  def do_test(base_img_path, fleece_img_path, nbd_sock_path, vm):
     log('Done')
 
 
-def test():
+def test(use_cbw):
     with iotests.FilePath('base.img') as base_img_path, \
          iotests.FilePath('fleece.img') as fleece_img_path, \
          iotests.FilePath('nbd.sock',
                           base_dir=iotests.sock_dir) as nbd_sock_path, \
          iotests.VM() as vm:
-        do_test(base_img_path, fleece_img_path, nbd_sock_path, vm)
+        do_test(use_cbw, base_img_path, fleece_img_path, nbd_sock_path, vm)
+
 
+log('=== Test backup(sync=none) based fleecing ===\n')
+test(False)
 
-test()
+log('=== Test filter based fleecing ===\n')
+test(True)
diff --git a/tests/qemu-iotests/tests/image-fleecing.out b/tests/qemu-iotests/tests/image-fleecing.out
index 314a1b54e9..e96d122a8b 100644
--- a/tests/qemu-iotests/tests/image-fleecing.out
+++ b/tests/qemu-iotests/tests/image-fleecing.out
@@ -1,3 +1,5 @@ 
+=== Test backup(sync=none) based fleecing ===
+
 --- Setting up images ---
 
 Done
@@ -65,3 +67,73 @@  read -P0xdc 32M 32k
 read -P0xcd 0x3ff0000 64k
 
 Done
+=== Test filter based fleecing ===
+
+--- Setting up images ---
+
+Done
+
+--- Launching VM ---
+
+Done
+
+--- Setting up Fleecing Graph ---
+
+{"return": {}}
+{"return": {}}
+{"return": {}}
+
+--- Setting up NBD Export ---
+
+{"return": {}}
+{"return": {}}
+
+--- Sanity Check ---
+
+read -P0x5d 0 64k
+read -P0xd5 1M 64k
+read -P0xdc 32M 64k
+read -P0xcd 0x3ff0000 64k
+read -P0 0x00f8000 32k
+read -P0 0x2010000 32k
+read -P0 0x3fe0000 64k
+
+--- Testing COW ---
+
+write -P0xab 0 64k
+{"return": ""}
+write -P0xad 0x00f8000 64k
+{"return": ""}
+write -P0x1d 0x2008000 64k
+{"return": ""}
+write -P0xea 0x3fe0000 64k
+{"return": ""}
+
+--- Verifying Data ---
+
+read -P0x5d 0 64k
+read -P0xd5 1M 64k
+read -P0xdc 32M 64k
+read -P0xcd 0x3ff0000 64k
+read -P0 0x00f8000 32k
+read -P0 0x2010000 32k
+read -P0 0x3fe0000 64k
+
+--- Cleanup ---
+
+{"return": {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}
+
+--- Confirming writes ---
+
+read -P0xab 0 64k
+read -P0xad 0x00f8000 64k
+read -P0x1d 0x2008000 64k
+read -P0xea 0x3fe0000 64k
+read -P0xd5 0x108000 32k
+read -P0xdc 32M 32k
+read -P0xcd 0x3ff0000 64k
+
+Done