qemu/tests/qemu-iotests/309.out
Eric Blake dbc7b01492 nbd: Add 'qemu-nbd -A' to expose allocation depth
Allow the server to expose an additional metacontext to be requested
by savvy clients.  qemu-nbd adds a new option -A to expose the
qemu:allocation-depth metacontext through NBD_CMD_BLOCK_STATUS; this
can also be set via QMP when using block-export-add.

qemu as client is hacked into viewing the key aspects of this new
context by abusing the already-experimental x-dirty-bitmap option to
collapse all depths greater than 2, which results in a tri-state value
visible in the output of 'qemu-img map --output=json' (yes, that means
x-dirty-bitmap is now a bit of a misnomer, but I didn't feel like
renaming it as it would introduce a needless break of back-compat,
even though we make no compat guarantees with x- members):

unallocated (depth 0) => "zero":false, "data":true
local (depth 1)       => "zero":false, "data":false
backing (depth 2+)    => "zero":true,  "data":true

libnbd as client is probably a nicer way to get at the information
without having to decipher such hacks in qemu as client. ;)

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20201027050556.269064-11-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-10-30 15:22:00 -05:00

23 lines
1.2 KiB
Plaintext

QA output created by 309
=== Initial image setup ===
Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=4194304
wrote 2097152/2097152 bytes at offset 0
2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
wrote 2097152/2097152 bytes at offset 1048576
2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
=== Check allocation over NBD ===
[{ "start": 0, "length": 1048576, "depth": 1, "zero": false, "data": true, "offset": 327680},
{ "start": 1048576, "length": 2097152, "depth": 0, "zero": false, "data": true, "offset": 327680},
{ "start": 3145728, "length": 1048576, "depth": 1, "zero": true, "data": false}]
[{ "start": 0, "length": 3145728, "depth": 0, "zero": false, "data": true, "offset": OFFSET},
{ "start": 3145728, "length": 1048576, "depth": 0, "zero": true, "data": false, "offset": OFFSET}]
[{ "start": 0, "length": 1048576, "depth": 0, "zero": true, "data": true, "offset": OFFSET},
{ "start": 1048576, "length": 2097152, "depth": 0, "zero": false, "data": false},
{ "start": 3145728, "length": 1048576, "depth": 0, "zero": false, "data": true, "offset": OFFSET}]
*** done