path: root/tests/qemu-iotests/142.out

QA output created by 142
Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=134217728
Formatting 'TEST_DIR/t.IMGFMT.snap', fmt=IMGFMT size=134217728
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT

=== Simple test for all cache modes ===

Testing: -drive file=TEST_DIR/t.qcow2,cache=none
QEMU X.Y.Z monitor - type 'help' for more information
(qemu) quit

Testing: -drive file=TEST_DIR/t.qcow2,cache=directsync
QEMU X.Y.Z monitor - type 'help' for more information
(qemu) quit

Testing: -drive file=TEST_DIR/t.qcow2,cache=writeback
QEMU X.Y.Z monitor - type 'help' for more information
(qemu) quit

Testing: -drive file=TEST_DIR/t.qcow2,cache=writethrough
QEMU X.Y.Z monitor - type 'help' for more information
(qemu) quit

Testing: -drive file=TEST_DIR/t.qcow2,cache=unsafe
QEMU X.Y.Z monitor - type 'help' for more information
(qemu) quit

Testing: -drive file=TEST_DIR/t.qcow2,cache=invalid_value
QEMU_PROG: -drive file=TEST_DIR/t.qcow2,cache=invalid_value: invalid cache option


=== Check inheritance of cache modes ===


--- Configure cache modes on the command line ---

cache.direct=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct


cache.writeback=off on none0
    Cache mode:       writethrough
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,file.cache.writeback=off: Block protocol 'file' doesn't support the option 'cache.writeback'

cache.writeback=off on backing
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.cache.writeback=off: Could not open backing file: Block format 'qcow2' does not support the option 'cache.writeback'

cache.writeback=off on backing-file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.file.cache.writeback=off: Could not open backing file: Block protocol 'file' doesn't support the option 'cache.writeback'


cache.no-flush=on on none0
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes

cache.no-flush=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes

cache.no-flush=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes

--- Cache modes after reopen (live snapshot) ---

cache.direct=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct


cache.writeback=off on none0
    Cache mode:       writethrough
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,file.cache.writeback=off: Block protocol 'file' doesn't support the option 'cache.writeback'

cache.writeback=off on backing
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.cache.writeback=off: Could not open backing file: Block format 'qcow2' does not support the option 'cache.writeback'

cache.writeback=off on backing-file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.file.cache.writeback=off: Could not open backing file: Block protocol 'file' doesn't support the option 'cache.writeback'


cache.no-flush=on on none0
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes

cache.no-flush=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes

cache.no-flush=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes

--- Change cache modes with reopen (qemu-io command, flags) ---

cache.direct=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct


cache.writeback=off on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.writeback=off on file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,file.cache.writeback=off: Block protocol 'file' doesn't support the option 'cache.writeback'

cache.writeback=off on backing
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.cache.writeback=off: Could not open backing file: Block format 'qcow2' does not support the option 'cache.writeback'

cache.writeback=off on backing-file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.file.cache.writeback=off: Could not open backing file: Block protocol 'file' doesn't support the option 'cache.writeback'


cache.no-flush=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.no-flush=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.no-flush=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes

cache.no-flush=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct, ignore flushes

--- Change cache modes with reopen (qemu-io command, options) ---

cache.direct=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct


cache.writeback=off on none0
    Cache mode:       writethrough, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.writeback=off on file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,file.cache.writeback=off: Block protocol 'file' doesn't support the option 'cache.writeback'

cache.writeback=off on backing
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.cache.writeback=off: Could not open backing file: Block format 'qcow2' does not support the option 'cache.writeback'

cache.writeback=off on backing-file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.file.cache.writeback=off: Could not open backing file: Block protocol 'file' doesn't support the option 'cache.writeback'


cache.no-flush=on on none0
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes

cache.no-flush=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.no-flush=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes

cache.no-flush=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct, ignore flushes

--- Change cache modes after snapshot ---

cache.direct=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct


cache.writeback=off on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,file.cache.writeback=off: Block protocol 'file' doesn't support the option 'cache.writeback'

cache.writeback=off on backing
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.cache.writeback=off: Could not open backing file: Block format 'qcow2' does not support the option 'cache.writeback'

cache.writeback=off on backing-file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.file.cache.writeback=off: Could not open backing file: Block protocol 'file' doesn't support the option 'cache.writeback'


cache.no-flush=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes

cache.no-flush=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes

cache.no-flush=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes

--- Change cache mode in parent, child has explicit option in JSON ---

    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, ignore flushes

=== Check that referenced BDSes don't inherit ===


--- Configure cache modes on the command line ---

cache.direct=on on blk
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on file
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback

cache.direct=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct


cache.writeback=off on blk
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback


cache.no-flush=on on blk
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on file
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback

cache.no-flush=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes

--- Cache modes after reopen (live snapshot) ---

cache.direct=on on blk
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback

cache.direct=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct


cache.writeback=off on blk
    Cache mode:       writethrough
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback


cache.no-flush=on on blk
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback

cache.no-flush=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes

--- Change cache modes with reopen (qemu-io command, flags) ---

cache.direct=on on blk
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback

cache.direct=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback

cache.direct=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct


cache.writeback=off on blk
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.writeback=off on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback


cache.no-flush=on on blk
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on file
    Cache mode:       writeback, direct
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback
    Cache mode:       writeback

cache.no-flush=on on backing
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback

cache.no-flush=on on backing-file
    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes

=== Reopening children instead of the root ===


--- Basic reopen ---

cache.direct=on on none0
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.direct=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct


cache.writeback=off on none0
    Cache mode:       writethrough
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.writeback=off on file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,file.cache.writeback=off: Block protocol 'file' doesn't support the option 'cache.writeback'

cache.writeback=off on backing
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.cache.writeback=off: Could not open backing file: Block format 'qcow2' does not support the option 'cache.writeback'

cache.writeback=off on backing-file
QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2,backing.file.filename=TEST_DIR/t.qcow2.base,node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,backing.file.cache.writeback=off: Could not open backing file: Block protocol 'file' doesn't support the option 'cache.writeback'


cache.no-flush=on on none0
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes

cache.no-flush=on on file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, ignore flushes
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct

cache.no-flush=on on backing
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct, ignore flushes
    Cache mode:       writeback, direct, ignore flushes

cache.no-flush=on on backing-file
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, direct, ignore flushes

--- Change cache mode after reopening child ---

    Cache mode:       writeback, direct
    Cache mode:       writeback
    Cache mode:       writeback, direct
    Cache mode:       writeback, ignore flushes
*** done