dbc7b01492
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>
78 lines
2.4 KiB
Bash
Executable File
78 lines
2.4 KiB
Bash
Executable File
#!/usr/bin/env bash
|
|
#
|
|
# Test qemu-nbd -A
|
|
#
|
|
# Copyright (C) 2018-2020 Red Hat, Inc.
|
|
#
|
|
# This program is free software; you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation; either version 2 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# This program is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
#
|
|
|
|
seq="$(basename $0)"
|
|
echo "QA output created by $seq"
|
|
|
|
status=1 # failure is the default!
|
|
|
|
_cleanup()
|
|
{
|
|
_cleanup_test_img
|
|
nbd_server_stop
|
|
}
|
|
trap "_cleanup; exit \$status" 0 1 2 3 15
|
|
|
|
# get standard environment, filters and checks
|
|
. ./common.rc
|
|
. ./common.filter
|
|
. ./common.nbd
|
|
|
|
_supported_fmt qcow2
|
|
_supported_proto file
|
|
_supported_os Linux
|
|
_require_command QEMU_NBD
|
|
|
|
echo
|
|
echo "=== Initial image setup ==="
|
|
echo
|
|
|
|
TEST_IMG="$TEST_IMG.base" _make_test_img 4M
|
|
$QEMU_IO -c 'w 0 2M' -f $IMGFMT "$TEST_IMG.base" | _filter_qemu_io
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT 4M
|
|
$QEMU_IO -c 'w 1M 2M' -f $IMGFMT "$TEST_IMG" | _filter_qemu_io
|
|
|
|
echo
|
|
echo "=== Check allocation over NBD ==="
|
|
echo
|
|
|
|
$QEMU_IMG map --output=json -f qcow2 "$TEST_IMG"
|
|
IMG="driver=nbd,server.type=unix,server.path=$nbd_unix_socket"
|
|
nbd_server_start_unix_socket -r -f qcow2 -A "$TEST_IMG"
|
|
# Normal -f raw NBD block status loses access to allocation information
|
|
$QEMU_IMG map --output=json --image-opts \
|
|
"$IMG" | _filter_qemu_img_map
|
|
# But when we use -A, coupled with x-dirty-bitmap in the client for feeding
|
|
# 2-bit block status from an alternative NBD metadata context (note that
|
|
# the client code for x-dirty-bitmap intentionally collapses all depths
|
|
# beyond 2 into a single value), we can determine:
|
|
# unallocated (depth 0) => "zero":false, "data":true
|
|
# local (depth 1) => "zero":false, "data":false
|
|
# backing (depth 2+) => "zero":true, "data":true
|
|
$QEMU_IMG map --output=json --image-opts \
|
|
"$IMG,x-dirty-bitmap=qemu:allocation-depth" | _filter_qemu_img_map
|
|
# More accurate results can be obtained by other NBD clients such as
|
|
# libnbd, but this test works without such external dependencies.
|
|
|
|
# success, all done
|
|
echo '*** done'
|
|
rm -f $seq.full
|
|
status=0
|