block-dirty-bitmap-add fails with "Operation not supported" in 4.2 rc5 (worked in 4.1)

[Nir Soffer]

We have a test for full backup flow testing that we can consume the
data using our nbd client.

The test[0] is starting a full backup flow, based on Eric examples
from [1] and [2].

This used to work in 4.1, and broke when I upgraded to 4.2 rc5. Here
is the error I get:

E               test.qmp.CommandFailed: Command {'execute':
'transaction', 'arguments': {'actions': [{'type': 'blockdev-backup',
'data': {'device': 'ide0-hd0', 'job-id': 'backup-sda', 'sync': 'none',
'target': 'backup-sda'}}, {'type': 'block-dirty-bitmap-add', 'data':
{'name': 'check1', 'node': 'ide0-hd0', 'persistent': True}}]}} failed:
{'class': 'GenericError', 'desc': "Can't store persistent bitmaps to
ide0-hd0: Operation not supported"}

I guess 4.2 change the way bitmaps are created?

[0] 
https://github.com/oVirt/ovirt-imageio/blob/c92835d5b2e0c865ddbd3f43eb5166cc905d7eeb/common/test/backup.py#L26
[1] https://www.spinics.net/linux/fedora/libvir/msg174457.html
[2] https://www.spinics.net/linux/fedora/libvir/msg174528.html

See complete flow from the test logs below.

Nir

---

13:55:11 DEBUG   (MainThread) [qemu_nbd] Starting qemu-nbd
['qemu-nbd', '--format', 'qcow2', '--export-name', b'',
'--persistent', '--cache=none', '--aio=native', '--discard=unmap',
'--socket=/var/tmp/imageio-storage/file-512-ext4-mount/file.sock',
'/var/tmp/imageio-storage/file-512-ext4-mount/file']
13:55:11 DEBUG   (MainThread) [test] Waiting for socket
/var/tmp/imageio-storage/file-512-ext4-mount/file.sock up to 1.000000
seconds
13:55:11 DEBUG   (MainThread) [test] Waited for
/var/tmp/imageio-storage/file-512-ext4-mount/file.sock 0.020641
seconds
13:55:11 DEBUG   (MainThread) [qemu_nbd] qemu-nbd socket ready
13:55:11 INFO    (MainThread) [nbd] Connecting to
/var/tmp/imageio-storage/file-512-ext4-mount/file.sock ''
13:55:11 DEBUG   (MainThread) [nbd] Received server flags: 3
13:55:11 DEBUG   (MainThread) [nbd] Sending client flags: 1
13:55:11 DEBUG   (MainThread) [nbd] Sending option: 8 data: b''
13:55:11 DEBUG   (MainThread) [nbd] Received reply magic=3e889045565a9
option=8 type=1 len=0
13:55:11 DEBUG   (MainThread) [nbd] Structured reply enabled
13:55:11 DEBUG   (MainThread) [nbd] Sending option: 10 data:
bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x0fbase:allocation')
13:55:11 DEBUG   (MainThread) [nbd] Received reply magic=3e889045565a9
option=10 type=4 len=19
13:55:11 DEBUG   (MainThread) [nbd] Meta context base:allocation is
available id=0
13:55:11 DEBUG   (MainThread) [nbd] Received reply magic=3e889045565a9
option=10 type=1 len=0
13:55:11 DEBUG   (MainThread) [nbd] Sending option: 7 data:
bytearray(b'\x00\x00\x00\x00\x00\x00')
13:55:11 DEBUG   (MainThread) [nbd] Received reply magic=3e889045565a9
option=7 type=3 len=14
13:55:11 DEBUG   (MainThread) [nbd] Received block size info minimum=1
preferred=4096 maximum=33554432
13:55:11 DEBUG   (MainThread) [nbd] Received reply magic=3e889045565a9
option=7 type=3 len=12
13:55:11 DEBUG   (MainThread) [nbd] Received export info
size=5368709120 flags=3309
13:55:11 DEBUG   (MainThread) [nbd] Received reply magic=3e889045565a9
option=7 type=1 len=0
13:55:11 INFO    (MainThread) [nbd] Ready for transmission
13:55:11 DEBUG   (MainThread) [nbd] Sending NBD_CMD_WRITE handle=0
offset=0 length=2 flags=0
13:55:11 DEBUG   (MainThread) [nbd] Sending NBD_CMD_WRITE handle=1
offset=1073741824 length=11 flags=0
13:55:11 DEBUG   (MainThread) [nbd] Sending NBD_CMD_WRITE handle=2
offset=2147483648 length=11 flags=0
13:55:11 DEBUG   (MainThread) [nbd] Sending NBD_CMD_WRITE handle=3
offset=3221225472 length=11 flags=0
13:55:11 DEBUG   (MainThread) [nbd] Sending NBD_CMD_WRITE handle=4
offset=4294967296 length=11 flags=0
13:55:11 DEBUG   (MainThread) [nbd] Sending NBD_CMD_FLUSH handle=5
offset=0 length=0 flags=0
13:55:11 INFO    (MainThread) [nbd] Initiating a soft disconnect
13:55:11 DEBUG   (MainThread) [nbd] Sending NBD_CMD_DISC handle=6
offset=0 length=0 flags=0
13:55:11 DEBUG   (MainThread) [qemu_nbd] Terminating qemu-nbd gracefully
13:55:11 DEBUG   (MainThread) [qemu_nbd] qemu-nbd terminated with exit code 0
13:55:11 DEBUG   (MainThread) [backup] Creating scratch disk
13:55:11 DEBUG   (MainThread) [qemu] Starting qemu ['qemu-kvm',
'-machine', 'accel=kvm:tcg', '-drive',
'file=/var/tmp/imageio-storage/file-512-ext4-mount/file,format=qcow2',
'-nographic', '-qmp',
'unix:/var/tmp/ovirt-imageio-common/test_full_backup_single_image_1/qmp.sock,server,nowait',
'-audiodev', 'none,id=1', '-S']
13:55:11 DEBUG   (MainThread) [test] Waiting for socket
/var/tmp/ovirt-imageio-common/test_full_backup_single_image_1/qmp.sock
up to 1.000000 seconds
13:55:11 DEBUG   (MainThread) [test] Waited for
/var/tmp/ovirt-imageio-common/test_full_backup_single_image_1/qmp.sock
0.040733 seconds
13:55:11 DEBUG   (MainThread) [qmp] Talking with qemu 4.1.95
13:55:11 DEBUG   (MainThread) [qmp] Sending {'execute': 'qmp_capabilities'}
13:55:11 DEBUG   (MainThread) [qmp] Received return: {}
13:55:11 DEBUG   (MainThread) [backup] Starting backup
13:55:11 DEBUG   (MainThread) [backup] Starting nbd server listening
on /var/tmp/ovirt-imageio-common/test_full_backup_single_image_1/sock
13:55:11 DEBUG   (MainThread) [qmp] Sending {'execute':
'nbd-server-start', 'arguments': {'addr': {'type': 'unix', 'data':
{'path': 
'/var/tmp/ovirt-imageio-common/test_full_backup_single_image_1/sock'}}}}
13:55:11 DEBUG   (MainThread) [qmp] Received return: {}
13:55:11 DEBUG   (MainThread) [qmp] Sending {'execute': 'query-block'}
13:55:11 DEBUG   (MainThread) [qmp] Received return: [{'io-status':
'ok', 'device': 'ide0-hd0', 'locked': False, 'removable': False,
'inserted': {'iops_rd': 0, 'detect_zeroes': 'off', 'image':
{'virtual-size': 5368709120, 'filename':
'/var/tmp/imageio-storage/file-512-ext4-mount/file', 'cluster-size':
65536, 'format': 'qcow2', 'actual-size': 860160, 'format-specific':
{'type': 'qcow2', 'data': {'compat': '1.1', 'lazy-refcounts': False,
'refcount-bits': 16, 'corrupt': False}}, 'dirty-flag': False},
'iops_wr': 0, 'ro': False, 'node-name': '#block126',
'backing_file_depth': 0, 'drv': 'qcow2', 'iops': 0, 'bps_wr': 0,
'write_threshold': 0, 'encrypted': False, 'bps': 0, 'bps_rd': 0,
'cache': {'no-flush': False, 'direct': False, 'writeback': True},
'file': '/var/tmp/imageio-storage/file-512-ext4-mount/file',
'encryption_key_missing': False}, 'qdev':
'/machine/unattached/device[24]', 'type': 'unknown'}, {'io-status':
'ok', 'device': 'ide1-cd0', 'locked': False, 'removable': True,
'qdev': '/machine/unattached/device[25]', 'tray_open': False, 'type':
'unknown'}, {'device': 'floppy0', 'locked': False, 'removable': True,
'qdev': '/machine/unattached/device[17]', 'type': 'unknown'},
{'device': 'sd0', 'locked': False, 'removable': True, 'type':
'unknown'}]
13:55:11 DEBUG   (MainThread) [backup] Adding backup node for ide0-hd0
13:55:11 DEBUG   (MainThread) [qmp] Sending {'execute':
'blockdev-add', 'arguments': {'driver': 'qcow2', 'node-name':
'backup-sda', 'file': {'driver': 'file', 'filename':
'/var/tmp/ovirt-imageio-common/test_full_backup_single_image_1/scratch.qcow2'},
'backing': 'ide0-hd0'}}
13:55:11 DEBUG   (MainThread) [qmp] Received return: {}
13:55:11 DEBUG   (MainThread) [backup] Starting backup job
13:55:11 DEBUG   (MainThread) [qmp] Sending {'execute': 'transaction',
'arguments': {'actions': [{'type': 'blockdev-backup', 'data':
{'device': 'ide0-hd0', 'job-id': 'backup-sda', 'sync': 'none',
'target': 'backup-sda'}}, {'type': 'block-dirty-bitmap-add', 'data':
{'name': 'check1', 'node': 'ide0-hd0', 'persistent': True}}]}}
13:55:11 DEBUG   (MainThread) [qmp] Received event: JOB_STATUS_CHANGE:
{'status': 'created', 'id': 'backup-sda'}
13:55:11 DEBUG   (MainThread) [qmp] Received event: JOB_STATUS_CHANGE:
{'status': 'aborting', 'id': 'backup-sda'}
13:55:11 DEBUG   (MainThread) [qmp] Received event: JOB_STATUS_CHANGE:
{'status': 'concluded', 'id': 'backup-sda'}
13:55:11 DEBUG   (MainThread) [qmp] Received event: JOB_STATUS_CHANGE:
{'status': 'null', 'id': 'backup-sda'}
13:55:11 DEBUG   (MainThread) [qemu] Terminating qemu gracefully
13:55:11 DEBUG   (MainThread) [qemu] qemu terminated with exit code 0