xref: /qemu/tests/qemu-iotests/124 (revision ec6f3fc3)
1#!/usr/bin/env python3
2# group: rw backing
3#
4# Tests for incremental drive-backup
5#
6# Copyright (C) 2015 John Snow for Red Hat, Inc.
7#
8# Based on 056.
9#
10# This program is free software; you can redistribute it and/or modify
11# it under the terms of the GNU General Public License as published by
12# the Free Software Foundation; either version 2 of the License, or
13# (at your option) any later version.
14#
15# This program is distributed in the hope that it will be useful,
16# but WITHOUT ANY WARRANTY; without even the implied warranty of
17# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18# GNU General Public License for more details.
19#
20# You should have received a copy of the GNU General Public License
21# along with this program.  If not, see <http://www.gnu.org/licenses/>.
22#
23
24import os
25import iotests
26from iotests import try_remove
27from qemu.qmp.qmp_client import ExecuteError
28
29
30def io_write_patterns(img, patterns):
31    for pattern in patterns:
32        iotests.qemu_io('-c', 'write -P%s %s %s' % pattern, img)
33
34
35def transaction_action(action, **kwargs):
36    return {
37        'type': action,
38        'data': dict((k.replace('_', '-'), v) for k, v in kwargs.items())
39    }
40
41
42def transaction_bitmap_clear(node, name, **kwargs):
43    return transaction_action('block-dirty-bitmap-clear',
44                              node=node, name=name, **kwargs)
45
46
47def transaction_drive_backup(device, target, **kwargs):
48    return transaction_action('drive-backup', job_id=device, device=device,
49                              target=target, **kwargs)
50
51
52class Bitmap:
53    def __init__(self, name, drive):
54        self.name = name
55        self.drive = drive
56        self.num = 0
57        self.backups = list()
58
59    def base_target(self):
60        return (self.drive['backup'], None)
61
62    def new_target(self, num=None):
63        if num is None:
64            num = self.num
65        self.num = num + 1
66        base = os.path.join(iotests.test_dir,
67                            "%s.%s." % (self.drive['id'], self.name))
68        suff = "%i.%s" % (num, self.drive['fmt'])
69        target = base + "inc" + suff
70        reference = base + "ref" + suff
71        self.backups.append((target, reference))
72        return (target, reference)
73
74    def last_target(self):
75        if self.backups:
76            return self.backups[-1]
77        return self.base_target()
78
79    def del_target(self):
80        for image in self.backups.pop():
81            try_remove(image)
82        self.num -= 1
83
84    def cleanup(self):
85        for backup in self.backups:
86            for image in backup:
87                try_remove(image)
88
89
90class TestIncrementalBackupBase(iotests.QMPTestCase):
91    def __init__(self, *args):
92        super(TestIncrementalBackupBase, self).__init__(*args)
93        self.bitmaps = list()
94        self.files = list()
95        self.drives = list()
96        self.vm = iotests.VM()
97        self.err_img = os.path.join(iotests.test_dir, 'err.%s' % iotests.imgfmt)
98
99
100    def setUp(self):
101        # Create a base image with a distinctive patterning
102        drive0 = self.add_node('drive0')
103        self.img_create(drive0['file'], drive0['fmt'])
104        self.vm.add_drive(drive0['file'], opts='node-name=node0')
105        self.write_default_pattern(drive0['file'])
106        self.vm.launch()
107
108
109    def write_default_pattern(self, target):
110        io_write_patterns(target, (('0x41', 0, 512),
111                                   ('0xd5', '1M', '32k'),
112                                   ('0xdc', '32M', '124k')))
113
114
115    def add_node(self, node_id, fmt=iotests.imgfmt, path=None, backup=None):
116        if path is None:
117            path = os.path.join(iotests.test_dir, '%s.%s' % (node_id, fmt))
118        if backup is None:
119            backup = os.path.join(iotests.test_dir,
120                                  '%s.full.backup.%s' % (node_id, fmt))
121
122        self.drives.append({
123            'id': node_id,
124            'file': path,
125            'backup': backup,
126            'fmt': fmt })
127        return self.drives[-1]
128
129
130    def img_create(self, img, fmt=iotests.imgfmt, size='64M',
131                   parent=None, parentFormat=None, **kwargs):
132        optargs = []
133        for k,v in kwargs.items():
134            optargs = optargs + ['-o', '%s=%s' % (k,v)]
135        args = ['create', '-f', fmt] + optargs + [img, size]
136        if parent:
137            if parentFormat is None:
138                parentFormat = fmt
139            args = args + ['-b', parent, '-F', parentFormat]
140        iotests.qemu_img(*args)
141        self.files.append(img)
142
143
144    def do_qmp_backup(self, error='Input/output error', **kwargs):
145        self.vm.cmd('drive-backup', **kwargs)
146        return self.wait_qmp_backup(kwargs['device'], error)
147
148
149    def ignore_job_status_change_events(self):
150        while True:
151            e = self.vm.event_wait(name="JOB_STATUS_CHANGE")
152            if e['data']['status'] == 'null':
153                break
154
155    def wait_qmp_backup(self, device, error='Input/output error'):
156        event = self.vm.event_wait(name="BLOCK_JOB_COMPLETED",
157                                   match={'data': {'device': device}})
158        self.assertNotEqual(event, None)
159        self.ignore_job_status_change_events()
160
161        try:
162            failure = self.dictpath(event, 'data/error')
163        except AssertionError:
164            # Backup succeeded.
165            self.assert_qmp(event, 'data/offset', event['data']['len'])
166            return True
167        else:
168            # Backup failed.
169            self.assert_qmp(event, 'data/error', error)
170            return False
171
172
173    def wait_qmp_backup_cancelled(self, device):
174        event = self.vm.event_wait(name='BLOCK_JOB_CANCELLED',
175                                   match={'data': {'device': device}})
176        self.assertNotEqual(event, None)
177        self.ignore_job_status_change_events()
178
179
180    def create_anchor_backup(self, drive=None):
181        if drive is None:
182            drive = self.drives[-1]
183        res = self.do_qmp_backup(job_id=drive['id'],
184                                 device=drive['id'], sync='full',
185                                 format=drive['fmt'], target=drive['backup'])
186        self.assertTrue(res)
187        self.files.append(drive['backup'])
188        return drive['backup']
189
190
191    def make_reference_backup(self, bitmap=None):
192        if bitmap is None:
193            bitmap = self.bitmaps[-1]
194        _, reference = bitmap.last_target()
195        res = self.do_qmp_backup(job_id=bitmap.drive['id'],
196                                 device=bitmap.drive['id'], sync='full',
197                                 format=bitmap.drive['fmt'], target=reference)
198        self.assertTrue(res)
199
200
201    def add_bitmap(self, name, drive, **kwargs):
202        bitmap = Bitmap(name, drive)
203        self.bitmaps.append(bitmap)
204        self.vm.cmd('block-dirty-bitmap-add', node=drive['id'],
205                    name=bitmap.name, **kwargs)
206        return bitmap
207
208
209    def prepare_backup(self, bitmap=None, parent=None, **kwargs):
210        if bitmap is None:
211            bitmap = self.bitmaps[-1]
212        if parent is None:
213            parent, _ = bitmap.last_target()
214
215        target, _ = bitmap.new_target()
216        self.img_create(target, bitmap.drive['fmt'], parent=parent,
217                        **kwargs)
218        return target
219
220
221    def create_incremental(self, bitmap=None, parent=None,
222                           parentFormat=None, validate=True,
223                           target=None):
224        if bitmap is None:
225            bitmap = self.bitmaps[-1]
226        if parent is None:
227            parent, _ = bitmap.last_target()
228
229        if target is None:
230            target = self.prepare_backup(bitmap, parent)
231        res = self.do_qmp_backup(job_id=bitmap.drive['id'],
232                                 device=bitmap.drive['id'],
233                                 sync='incremental', bitmap=bitmap.name,
234                                 format=bitmap.drive['fmt'], target=target,
235                                 mode='existing')
236        if not res:
237            bitmap.del_target();
238            self.assertFalse(validate)
239        else:
240            self.make_reference_backup(bitmap)
241        return res
242
243
244    def check_backups(self):
245        for bitmap in self.bitmaps:
246            for incremental, reference in bitmap.backups:
247                self.assertTrue(iotests.compare_images(incremental, reference))
248            last = bitmap.last_target()[0]
249            self.assertTrue(iotests.compare_images(last, bitmap.drive['file']))
250
251
252    def hmp_io_writes(self, drive, patterns):
253        for pattern in patterns:
254            self.vm.hmp_qemu_io(drive, 'write -P%s %s %s' % pattern)
255        self.vm.hmp_qemu_io(drive, 'flush')
256
257
258    def do_incremental_simple(self, **kwargs):
259        self.create_anchor_backup()
260        self.add_bitmap('bitmap0', self.drives[0], **kwargs)
261
262        # Sanity: Create a "hollow" incremental backup
263        self.create_incremental()
264        # Three writes: One complete overwrite, one new segment,
265        # and one partial overlap.
266        self.hmp_io_writes(self.drives[0]['id'], (('0xab', 0, 512),
267                                                  ('0xfe', '16M', '256k'),
268                                                  ('0x64', '32736k', '64k')))
269        self.create_incremental()
270        # Three more writes, one of each kind, like above
271        self.hmp_io_writes(self.drives[0]['id'], (('0x9a', 0, 512),
272                                                  ('0x55', '8M', '352k'),
273                                                  ('0x78', '15872k', '1M')))
274        self.create_incremental()
275        self.vm.shutdown()
276        self.check_backups()
277
278
279    def tearDown(self):
280        self.vm.shutdown()
281        for bitmap in self.bitmaps:
282            bitmap.cleanup()
283        for filename in self.files:
284            try_remove(filename)
285
286
287
288class TestIncrementalBackup(TestIncrementalBackupBase):
289    def test_incremental_simple(self):
290        '''
291        Test: Create and verify three incremental backups.
292
293        Create a bitmap and a full backup before VM execution begins,
294        then create a series of three incremental backups "during execution,"
295        i.e.; after IO requests begin modifying the drive.
296        '''
297        return self.do_incremental_simple()
298
299
300    def test_small_granularity(self):
301        '''
302        Test: Create and verify backups made with a small granularity bitmap.
303
304        Perform the same test as test_incremental_simple, but with a granularity
305        of only 32KiB instead of the present default of 64KiB.
306        '''
307        return self.do_incremental_simple(granularity=32768)
308
309
310    def test_large_granularity(self):
311        '''
312        Test: Create and verify backups made with a large granularity bitmap.
313
314        Perform the same test as test_incremental_simple, but with a granularity
315        of 128KiB instead of the present default of 64KiB.
316        '''
317        return self.do_incremental_simple(granularity=131072)
318
319
320    def test_larger_cluster_target(self):
321        '''
322        Test: Create and verify backups made to a larger cluster size target.
323
324        With a default granularity of 64KiB, verify that backups made to a
325        larger cluster size target of 128KiB without a backing file works.
326        '''
327        drive0 = self.drives[0]
328
329        # Create a cluster_size=128k full backup / "anchor" backup
330        self.img_create(drive0['backup'], cluster_size='128k')
331        self.assertTrue(self.do_qmp_backup(device=drive0['id'], sync='full',
332                                           format=drive0['fmt'],
333                                           target=drive0['backup'],
334                                           mode='existing'))
335
336        # Create bitmap and dirty it with some new writes.
337        # overwrite [32736, 32799] which will dirty bitmap clusters at
338        # 32M-64K and 32M. 32M+64K will be left undirtied.
339        bitmap0 = self.add_bitmap('bitmap0', drive0)
340        self.hmp_io_writes(drive0['id'],
341                           (('0xab', 0, 512),
342                            ('0xfe', '16M', '256k'),
343                            ('0x64', '32736k', '64k')))
344        # Check the dirty bitmap stats
345        self.assertTrue(self.vm.check_bitmap_status(
346            'node0', bitmap0.name, {
347                'name': 'bitmap0',
348                'count': 458752,
349                'granularity': 65536,
350                'persistent': False
351            }))
352
353        # Prepare a cluster_size=128k backup target without a backing file.
354        (target, _) = bitmap0.new_target()
355        self.img_create(target, bitmap0.drive['fmt'], cluster_size='128k')
356
357        # Perform Incremental Backup
358        self.assertTrue(self.do_qmp_backup(device=bitmap0.drive['id'],
359                                           sync='incremental',
360                                           bitmap=bitmap0.name,
361                                           format=bitmap0.drive['fmt'],
362                                           target=target,
363                                           mode='existing'))
364        self.make_reference_backup(bitmap0)
365
366        # Add the backing file, then compare and exit.
367        iotests.qemu_img('rebase', '-f', drive0['fmt'], '-u', '-b',
368                         drive0['backup'], '-F', drive0['fmt'], target)
369        self.vm.shutdown()
370        self.check_backups()
371
372
373    def test_incremental_transaction(self):
374        '''Test: Verify backups made from transactionally created bitmaps.
375
376        Create a bitmap "before" VM execution begins, then create a second
377        bitmap AFTER writes have already occurred. Use transactions to create
378        a full backup and synchronize both bitmaps to this backup.
379        Create an incremental backup through both bitmaps and verify that
380        both backups match the current drive0 image.
381        '''
382
383        drive0 = self.drives[0]
384        bitmap0 = self.add_bitmap('bitmap0', drive0)
385        self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
386                                          ('0xfe', '16M', '256k'),
387                                          ('0x64', '32736k', '64k')))
388        bitmap1 = self.add_bitmap('bitmap1', drive0)
389
390        self.vm.cmd('transaction', actions=[
391            transaction_bitmap_clear(bitmap0.drive['id'], bitmap0.name),
392            transaction_bitmap_clear(bitmap1.drive['id'], bitmap1.name),
393            transaction_drive_backup(drive0['id'], drive0['backup'],
394                                     sync='full', format=drive0['fmt'])
395        ])
396        self.wait_until_completed(drive0['id'])
397        self.files.append(drive0['backup'])
398
399        self.hmp_io_writes(drive0['id'], (('0x9a', 0, 512),
400                                          ('0x55', '8M', '352k'),
401                                          ('0x78', '15872k', '1M')))
402        # Both bitmaps should be correctly in sync.
403        self.create_incremental(bitmap0)
404        self.create_incremental(bitmap1)
405        self.vm.shutdown()
406        self.check_backups()
407
408
409    def do_transaction_failure_test(self, race=False):
410        # Create a second drive, with pattern:
411        drive1 = self.add_node('drive1')
412        self.img_create(drive1['file'], drive1['fmt'])
413        io_write_patterns(drive1['file'], (('0x14', 0, 512),
414                                           ('0x5d', '1M', '32k'),
415                                           ('0xcd', '32M', '124k')))
416
417        # Create a blkdebug interface to this img as 'drive1'
418        self.vm.cmd('blockdev-add',
419            node_name=drive1['id'],
420            driver=drive1['fmt'],
421            file={
422                'driver': 'blkdebug',
423                'image': {
424                    'driver': 'file',
425                    'filename': drive1['file']
426                },
427                'set-state': [{
428                    'event': 'flush_to_disk',
429                    'state': 1,
430                    'new_state': 2
431                }],
432                'inject-error': [{
433                    'event': 'read_aio',
434                    'errno': 5,
435                    'state': 2,
436                    'immediately': False,
437                    'once': True
438                }],
439            }
440        )
441
442        # Create bitmaps and full backups for both drives
443        drive0 = self.drives[0]
444        dr0bm0 = self.add_bitmap('bitmap0', drive0)
445        dr1bm0 = self.add_bitmap('bitmap0', drive1)
446        self.create_anchor_backup(drive0)
447        self.create_anchor_backup(drive1)
448        self.assert_no_active_block_jobs()
449        self.assertFalse(self.vm.get_qmp_events(wait=False))
450
451        # Emulate some writes
452        if not race:
453            self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
454                                              ('0xfe', '16M', '256k'),
455                                              ('0x64', '32736k', '64k')))
456        self.hmp_io_writes(drive1['id'], (('0xba', 0, 512),
457                                          ('0xef', '16M', '256k'),
458                                          ('0x46', '32736k', '64k')))
459
460        # Create incremental backup targets
461        target0 = self.prepare_backup(dr0bm0)
462        target1 = self.prepare_backup(dr1bm0)
463
464        # Ask for a new incremental backup per-each drive,
465        # expecting drive1's backup to fail. In the 'race' test,
466        # we expect drive1 to attempt to cancel the empty drive0 job.
467        transaction = [
468            transaction_drive_backup(drive0['id'], target0, sync='incremental',
469                                     format=drive0['fmt'], mode='existing',
470                                     bitmap=dr0bm0.name),
471            transaction_drive_backup(drive1['id'], target1, sync='incremental',
472                                     format=drive1['fmt'], mode='existing',
473                                     bitmap=dr1bm0.name)
474        ]
475        self.vm.cmd('transaction', actions=transaction,
476                    properties={'completion-mode': 'grouped'} )
477
478        # Observe that drive0's backup is cancelled and drive1 completes with
479        # an error.
480        self.wait_qmp_backup_cancelled(drive0['id'])
481        self.assertFalse(self.wait_qmp_backup(drive1['id']))
482        error = self.vm.event_wait('BLOCK_JOB_ERROR')
483        self.assert_qmp(error, 'data', {'device': drive1['id'],
484                                        'action': 'report',
485                                        'operation': 'read'})
486        self.assertFalse(self.vm.get_qmp_events(wait=False))
487        self.assert_no_active_block_jobs()
488
489        # Delete drive0's successful target and eliminate our record of the
490        # unsuccessful drive1 target.
491        dr0bm0.del_target()
492        dr1bm0.del_target()
493        if race:
494            # Don't re-run the transaction, we only wanted to test the race.
495            self.vm.shutdown()
496            return
497
498        # Re-run the same transaction:
499        target0 = self.prepare_backup(dr0bm0)
500        target1 = self.prepare_backup(dr1bm0)
501
502        # Re-run the exact same transaction.
503        self.vm.cmd('transaction', actions=transaction,
504                    properties={'completion-mode':'grouped'})
505
506        # Both should complete successfully this time.
507        self.assertTrue(self.wait_qmp_backup(drive0['id']))
508        self.assertTrue(self.wait_qmp_backup(drive1['id']))
509        self.make_reference_backup(dr0bm0)
510        self.make_reference_backup(dr1bm0)
511        self.assertFalse(self.vm.get_qmp_events(wait=False))
512        self.assert_no_active_block_jobs()
513
514        # And the images should of course validate.
515        self.vm.shutdown()
516        self.check_backups()
517
518    def test_transaction_failure(self):
519        '''Test: Verify backups made from a transaction that partially fails.
520
521        Add a second drive with its own unique pattern, and add a bitmap to each
522        drive. Use blkdebug to interfere with the backup on just one drive and
523        attempt to create a coherent incremental backup across both drives.
524
525        verify a failure in one but not both, then delete the failed stubs and
526        re-run the same transaction.
527
528        verify that both incrementals are created successfully.
529        '''
530        self.do_transaction_failure_test()
531
532    def test_transaction_failure_race(self):
533        '''Test: Verify that transactions with jobs that have no data to
534        transfer do not cause race conditions in the cancellation of the entire
535        transaction job group.
536        '''
537        self.do_transaction_failure_test(race=True)
538
539
540    def test_sync_dirty_bitmap_missing(self):
541        self.assert_no_active_block_jobs()
542        self.files.append(self.err_img)
543        result = self.vm.qmp('drive-backup', device=self.drives[0]['id'],
544                             sync='incremental', format=self.drives[0]['fmt'],
545                             target=self.err_img)
546        self.assert_qmp(result, 'error/class', 'GenericError')
547
548
549    def test_sync_dirty_bitmap_not_found(self):
550        self.assert_no_active_block_jobs()
551        self.files.append(self.err_img)
552        result = self.vm.qmp('drive-backup', device=self.drives[0]['id'],
553                             sync='incremental', bitmap='unknown',
554                             format=self.drives[0]['fmt'], target=self.err_img)
555        self.assert_qmp(result, 'error/class', 'GenericError')
556
557
558    def test_sync_dirty_bitmap_bad_granularity(self):
559        '''
560        Test: Test what happens if we provide an improper granularity.
561
562        The granularity must always be a power of 2.
563        '''
564        self.assert_no_active_block_jobs()
565        self.assertRaises(ExecuteError, self.add_bitmap,
566                          'bitmap0', self.drives[0],
567                          granularity=64000)
568
569    def test_growing_before_backup(self):
570        '''
571        Test: Add a bitmap, truncate the image, write past the old
572              end, do a backup.
573
574        Incremental backup should not ignore dirty bits past the old
575        image end.
576        '''
577        self.assert_no_active_block_jobs()
578
579        self.create_anchor_backup()
580
581        self.add_bitmap('bitmap0', self.drives[0])
582
583        self.vm.cmd('block_resize', device=self.drives[0]['id'],
584                    size=(65 * 1048576))
585
586        # Dirty the image past the old end
587        self.vm.hmp_qemu_io(self.drives[0]['id'], 'write 64M 64k')
588
589        target = self.prepare_backup(size='65M')
590        self.create_incremental(target=target)
591
592        self.vm.shutdown()
593        self.check_backups()
594
595
596class TestIncrementalBackupBlkdebug(TestIncrementalBackupBase):
597    '''Incremental backup tests that utilize a BlkDebug filter on drive0.'''
598
599    def setUp(self):
600        drive0 = self.add_node('drive0')
601        self.img_create(drive0['file'], drive0['fmt'])
602        self.write_default_pattern(drive0['file'])
603        self.vm.launch()
604
605    def test_incremental_failure(self):
606        '''Test: Verify backups made after a failure are correct.
607
608        Simulate a failure during an incremental backup block job,
609        emulate additional writes, then create another incremental backup
610        afterwards and verify that the backup created is correct.
611        '''
612
613        drive0 = self.drives[0]
614        self.vm.cmd('blockdev-add',
615            node_name=drive0['id'],
616            driver=drive0['fmt'],
617            file={
618                'driver': 'blkdebug',
619                'image': {
620                    'driver': 'file',
621                    'filename': drive0['file']
622                },
623                'set-state': [{
624                    'event': 'flush_to_disk',
625                    'state': 1,
626                    'new_state': 2
627                }],
628                'inject-error': [{
629                    'event': 'read_aio',
630                    'errno': 5,
631                    'state': 2,
632                    'immediately': False,
633                    'once': True
634                }],
635            }
636        )
637
638        self.create_anchor_backup(drive0)
639        self.add_bitmap('bitmap0', drive0)
640        # Note: at this point, during a normal execution,
641        # Assume that the VM resumes and begins issuing IO requests here.
642
643        self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
644                                          ('0xfe', '16M', '256k'),
645                                          ('0x64', '32736k', '64k')))
646
647        result = self.create_incremental(validate=False)
648        self.assertFalse(result)
649        self.hmp_io_writes(drive0['id'], (('0x9a', 0, 512),
650                                          ('0x55', '8M', '352k'),
651                                          ('0x78', '15872k', '1M')))
652        self.create_incremental()
653        self.vm.shutdown()
654        self.check_backups()
655
656    def test_incremental_pause(self):
657        """
658        Test an incremental backup that errors into a pause and is resumed.
659        """
660
661        drive0 = self.drives[0]
662        # NB: The blkdebug script here looks for a "flush, read" pattern.
663        # The flush occurs in hmp_io_writes, and the read during the block job.
664        self.vm.cmd('blockdev-add',
665                    node_name=drive0['id'],
666                    driver=drive0['fmt'],
667                    file={
668                        'driver': 'blkdebug',
669                        'image': {
670                            'driver': 'file',
671                            'filename': drive0['file']
672                        },
673                        'set-state': [{
674                            'event': 'flush_to_disk',
675                            'state': 1,
676                            'new_state': 2
677                        }],
678                        'inject-error': [{
679                            'event': 'read_aio',
680                            'errno': 5,
681                            'state': 2,
682                            'immediately': False,
683                            'once': True
684                        }],
685                    })
686        self.create_anchor_backup(drive0)
687        bitmap = self.add_bitmap('bitmap0', drive0)
688
689        # Emulate guest activity
690        self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
691                                          ('0xfe', '16M', '256k'),
692                                          ('0x64', '32736k', '64k')))
693
694        # Bitmap Status Check
695        self.assertTrue(self.vm.check_bitmap_status(
696            drive0['id'], bitmap.name, {
697                'count': 458752,
698                'granularity': 65536,
699                'busy': False,
700                'recording': True
701            }))
702
703        # Start backup
704        parent, _ = bitmap.last_target()
705        target = self.prepare_backup(bitmap, parent)
706        self.vm.cmd('drive-backup',
707                    job_id=bitmap.drive['id'],
708                    device=bitmap.drive['id'],
709                    sync='incremental',
710                    bitmap=bitmap.name,
711                    format=bitmap.drive['fmt'],
712                    target=target,
713                    mode='existing',
714                    on_source_error='stop')
715
716        # Wait for the error
717        event = self.vm.event_wait(name="BLOCK_JOB_ERROR",
718                                   match={"data":{"device":bitmap.drive['id']}})
719        self.assert_qmp(event, 'data', {'device': bitmap.drive['id'],
720                                        'action': 'stop',
721                                        'operation': 'read'})
722
723        # Bitmap Status Check
724        self.assertTrue(self.vm.check_bitmap_status(
725            drive0['id'], bitmap.name, {
726                'count': 458752,
727                'granularity': 65536,
728                'busy': True,
729                'recording': True
730            }))
731
732        # Resume and check incremental backup for consistency
733        self.vm.cmd('block-job-resume', device=bitmap.drive['id'])
734        self.wait_qmp_backup(bitmap.drive['id'])
735
736        # Bitmap Status Check
737        self.assertTrue(self.vm.check_bitmap_status(
738            drive0['id'], bitmap.name, {
739                'count': 0,
740                'granularity': 65536,
741                'busy': False,
742                'recording': True
743            }))
744
745        # Finalize / Cleanup
746        self.make_reference_backup(bitmap)
747        self.vm.shutdown()
748        self.check_backups()
749
750
751if __name__ == '__main__':
752    iotests.main(supported_fmts=['qcow2'],
753                 supported_protocols=['file'])
754