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>stable-6.0
Eric Blake
parent
71719cd57f
commit
dbc7b01492
26
block/nbd.c
26
block/nbd.c
|
|
@ -135,6 +135,7 @@ typedef struct BDRVNBDState {
|
|||
QCryptoTLSCreds *tlscreds;
|
||||
const char *hostname;
|
||||
char *x_dirty_bitmap;
|
||||
bool alloc_depth;
|
||||
|
||||
bool wait_connect;
|
||||
NBDConnectThread *connect_thread;
|
||||
|
|
@ -961,6 +962,16 @@ static int nbd_parse_blockstatus_payload(BDRVNBDState *s,
|
|||
trace_nbd_parse_blockstatus_compliance("extent length too large");
|
||||
}
|
||||
|
||||
/*
|
||||
* HACK: if we are using x-dirty-bitmaps to access
|
||||
* qemu:allocation-depth, treat all depths > 2 the same as 2,
|
||||
* since nbd_client_co_block_status is only expecting the low two
|
||||
* bits to be set.
|
||||
*/
|
||||
if (s->alloc_depth && extent->flags > 2) {
|
||||
extent->flags = 2;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
@ -1795,11 +1806,16 @@ static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc,
|
|||
s->sioc = NULL;
|
||||
return ret;
|
||||
}
|
||||
if (s->x_dirty_bitmap && !s->info.base_allocation) {
|
||||
error_setg(errp, "requested x-dirty-bitmap %s not found",
|
||||
s->x_dirty_bitmap);
|
||||
ret = -EINVAL;
|
||||
goto fail;
|
||||
if (s->x_dirty_bitmap) {
|
||||
if (!s->info.base_allocation) {
|
||||
error_setg(errp, "requested x-dirty-bitmap %s not found",
|
||||
s->x_dirty_bitmap);
|
||||
ret = -EINVAL;
|
||||
goto fail;
|
||||
}
|
||||
if (strcmp(s->x_dirty_bitmap, "qemu:allocation-depth") == 0) {
|
||||
s->alloc_depth = true;
|
||||
}
|
||||
}
|
||||
if (s->info.flags & NBD_FLAG_READ_ONLY) {
|
||||
ret = bdrv_apply_auto_read_only(bs, "NBD export is read-only", errp);
|
||||
|
|
|
|||
|
|
@ -72,10 +72,16 @@ driver options if ``--image-opts`` is specified.
|
|||
|
||||
Export the disk as read-only.
|
||||
|
||||
.. option:: -A, --allocation-depth
|
||||
|
||||
Expose allocation depth information via the
|
||||
``qemu:allocation-depth`` metadata context accessible through
|
||||
NBD_OPT_SET_META_CONTEXT.
|
||||
|
||||
.. option:: -B, --bitmap=NAME
|
||||
|
||||
If *filename* has a qcow2 persistent bitmap *NAME*, expose
|
||||
that bitmap via the ``qemu:dirty-bitmap:NAME`` context
|
||||
that bitmap via the ``qemu:dirty-bitmap:NAME`` metadata context
|
||||
accessible through NBD_OPT_SET_META_CONTEXT.
|
||||
|
||||
.. option:: -s, --snapshot
|
||||
|
|
|
|||
|
|
@ -1641,6 +1641,8 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
|
|||
bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true);
|
||||
}
|
||||
|
||||
exp->allocation_depth = arg->allocation_depth;
|
||||
|
||||
blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
|
||||
|
||||
QTAILQ_INSERT_TAIL(&exports, exp, next);
|
||||
|
|
|
|||
|
|
@ -3905,9 +3905,12 @@
|
|||
#
|
||||
# @tls-creds: TLS credentials ID
|
||||
#
|
||||
# @x-dirty-bitmap: A "qemu:dirty-bitmap:NAME" string to query in place of
|
||||
# @x-dirty-bitmap: A metadata context name such as "qemu:dirty-bitmap:NAME"
|
||||
# or "qemu:allocation-depth" to query in place of the
|
||||
# traditional "base:allocation" block status (see
|
||||
# NBD_OPT_LIST_META_CONTEXT in the NBD protocol) (since 3.0)
|
||||
# NBD_OPT_LIST_META_CONTEXT in the NBD protocol; and
|
||||
# yes, naming this option x-context would have made
|
||||
# more sense) (since 3.0)
|
||||
#
|
||||
# @reconnect-delay: On an unexpected disconnect, the nbd client tries to
|
||||
# connect again until succeeding or encountering a serious
|
||||
|
|
|
|||
|
|
@ -90,11 +90,16 @@
|
|||
# the metadata context name "qemu:dirty-bitmap:BITMAP" to inspect
|
||||
# each bitmap.
|
||||
#
|
||||
# @allocation-depth: Also export the allocation depth map for @device, so
|
||||
# the NBD client can use NBD_OPT_SET_META_CONTEXT with
|
||||
# the metadata context name "qemu:allocation-depth" to
|
||||
# inspect allocation details. (since 5.2)
|
||||
#
|
||||
# Since: 5.2
|
||||
##
|
||||
{ 'struct': 'BlockExportOptionsNbd',
|
||||
'base': 'BlockExportOptionsNbdBase',
|
||||
'data': { '*bitmaps': ['str'] } }
|
||||
'data': { '*bitmaps': ['str'], '*allocation-depth': 'bool' } }
|
||||
|
||||
##
|
||||
# @BlockExportOptionsVhostUserBlk:
|
||||
|
|
|
|||
12
qemu-nbd.c
12
qemu-nbd.c
|
|
@ -100,6 +100,7 @@ static void usage(const char *name)
|
|||
"\n"
|
||||
"Exposing part of the image:\n"
|
||||
" -o, --offset=OFFSET offset into the image\n"
|
||||
" -A, --allocation-depth expose the allocation depth\n"
|
||||
" -B, --bitmap=NAME expose a persistent dirty bitmap\n"
|
||||
"\n"
|
||||
"General purpose options:\n"
|
||||
|
|
@ -524,7 +525,7 @@ int main(int argc, char **argv)
|
|||
char *device = NULL;
|
||||
QemuOpts *sn_opts = NULL;
|
||||
const char *sn_id_or_name = NULL;
|
||||
const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:B:L";
|
||||
const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:AB:L";
|
||||
struct option lopt[] = {
|
||||
{ "help", no_argument, NULL, 'h' },
|
||||
{ "version", no_argument, NULL, 'V' },
|
||||
|
|
@ -533,6 +534,7 @@ int main(int argc, char **argv)
|
|||
{ "socket", required_argument, NULL, 'k' },
|
||||
{ "offset", required_argument, NULL, 'o' },
|
||||
{ "read-only", no_argument, NULL, 'r' },
|
||||
{ "allocation-depth", no_argument, NULL, 'A' },
|
||||
{ "bitmap", required_argument, NULL, 'B' },
|
||||
{ "connect", required_argument, NULL, 'c' },
|
||||
{ "disconnect", no_argument, NULL, 'd' },
|
||||
|
|
@ -575,6 +577,7 @@ int main(int argc, char **argv)
|
|||
const char *export_name = NULL; /* defaults to "" later for server mode */
|
||||
const char *export_description = NULL;
|
||||
strList *bitmaps = NULL;
|
||||
bool alloc_depth = false;
|
||||
const char *tlscredsid = NULL;
|
||||
bool imageOpts = false;
|
||||
bool writethrough = true;
|
||||
|
|
@ -689,6 +692,9 @@ int main(int argc, char **argv)
|
|||
readonly = true;
|
||||
flags &= ~BDRV_O_RDWR;
|
||||
break;
|
||||
case 'A':
|
||||
alloc_depth = true;
|
||||
break;
|
||||
case 'B':
|
||||
QAPI_LIST_PREPEND(bitmaps, g_strdup(optarg));
|
||||
break;
|
||||
|
|
@ -787,7 +793,7 @@ int main(int argc, char **argv)
|
|||
}
|
||||
if (export_name || export_description || dev_offset ||
|
||||
device || disconnect || fmt || sn_id_or_name || bitmaps ||
|
||||
seen_aio || seen_discard || seen_cache) {
|
||||
alloc_depth || seen_aio || seen_discard || seen_cache) {
|
||||
error_report("List mode is incompatible with per-device settings");
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
|
@ -1073,6 +1079,8 @@ int main(int argc, char **argv)
|
|||
.description = g_strdup(export_description),
|
||||
.has_bitmaps = !!bitmaps,
|
||||
.bitmaps = bitmaps,
|
||||
.has_allocation_depth = alloc_depth,
|
||||
.allocation_depth = alloc_depth,
|
||||
},
|
||||
};
|
||||
blk_exp_add(export_opts, &error_fatal);
|
||||
|
|
|
|||
|
|
@ -0,0 +1,77 @@
|
|||
#!/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
|
||||
|
|
@ -0,0 +1,22 @@
|
|||
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
|
||||
|
|
@ -315,3 +315,4 @@
|
|||
304 rw quick
|
||||
305 rw quick
|
||||
307 rw quick export
|
||||
309 rw auto quick
|
||||
|
|
|
|||
Loading…
Reference in New Issue