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[PATCH 3/3] nbd: Add 'qemu-nbd -A' to expose allocation depth
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From: |
Eric Blake |
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Subject: |
[PATCH 3/3] nbd: Add 'qemu-nbd -A' to expose allocation depth |
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Date: |
Fri, 25 Sep 2020 15:32:49 -0500 |
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 nbd-server-add.
qemu as client can be hacked into viewing this new context by using
the now-misnamed x-dirty-bitmap option when creating an NBD blockdev;
although it is worth noting the decoding of how such context
information will appear in 'qemu-img map --output=json':
NBD_STATE_DEPTH_UNALLOC => "zero":false, "data":true
NBD_STATE_DEPTH_LOCAL => "zero":false, "data":false
NBD_STATE_DEPTH_BACKING => "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>
---
docs/tools/qemu-nbd.rst | 6 ++++
qapi/block-core.json | 7 ++--
include/block/nbd.h | 7 ++--
blockdev-nbd.c | 3 +-
nbd/server.c | 8 +++--
qemu-nbd.c | 16 ++++++---
tests/qemu-iotests/309 | 73 ++++++++++++++++++++++++++++++++++++++
tests/qemu-iotests/309.out | 22 ++++++++++++
tests/qemu-iotests/group | 1 +
9 files changed, 129 insertions(+), 14 deletions(-)
create mode 100755 tests/qemu-iotests/309
create mode 100644 tests/qemu-iotests/309.out
diff --git a/docs/tools/qemu-nbd.rst b/docs/tools/qemu-nbd.rst
index 667861cb22e9..0e545a97cfa3 100644
--- a/docs/tools/qemu-nbd.rst
+++ b/docs/tools/qemu-nbd.rst
@@ -72,6 +72,12 @@ 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`` context accessible through
+ NBD_OPT_SET_META_CONTEXT.
+
.. option:: -B, --bitmap=NAME
If *filename* has a qcow2 persistent bitmap *NAME*, expose
diff --git a/qapi/block-core.json b/qapi/block-core.json
index b3ec30a83cd7..84f7a7a34dc1 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -3874,9 +3874,12 @@
#
# @tls-creds: TLS credentials ID
#
-# @x-dirty-bitmap: A "qemu:dirty-bitmap:NAME" string to query in place of
+# @x-dirty-bitmap: A metacontext 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
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 71a2623f7842..f660e0274ce3 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -336,9 +336,10 @@ typedef struct NBDClient NBDClient;
NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
uint64_t size, const char *name, const char *desc,
- const char *bitmap, bool readonly, bool shared,
- void (*close)(NBDExport *), bool writethrough,
- BlockBackend *on_eject_blk, Error **errp);
+ bool alloc_depth, const char *bitmap, bool readonly,
+ bool shared, void (*close)(NBDExport *),
+ bool writethrough, BlockBackend *on_eject_blk,
+ Error **errp);
void nbd_export_close(NBDExport *exp);
void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
void nbd_export_get(NBDExport *exp);
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 1a95d89f0096..562ea3751b85 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -203,7 +203,8 @@ void qmp_nbd_server_add(BlockExportNbd *arg, Error **errp)
arg->writable = false;
}
- exp = nbd_export_new(bs, 0, len, arg->name, arg->description, arg->bitmap,
+ exp = nbd_export_new(bs, 0, len, arg->name, arg->description,
+ arg->alloc, arg->bitmap,
!arg->writable, !arg->writable,
NULL, false, on_eject_blk, errp);
if (!exp) {
diff --git a/nbd/server.c b/nbd/server.c
index 02d5fb375b24..f5e0e115b703 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1450,9 +1450,10 @@ static void nbd_eject_notifier(Notifier *n, void *data)
NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
uint64_t size, const char *name, const char *desc,
- const char *bitmap, bool readonly, bool shared,
- void (*close)(NBDExport *), bool writethrough,
- BlockBackend *on_eject_blk, Error **errp)
+ bool alloc_depth, const char *bitmap, bool readonly,
+ bool shared, void (*close)(NBDExport *),
+ bool writethrough, BlockBackend *on_eject_blk,
+ Error **errp)
{
AioContext *ctx;
BlockBackend *blk;
@@ -1545,6 +1546,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t
dev_offset,
assert(strlen(exp->export_bitmap_context) < NBD_MAX_STRING_SIZE);
}
+ exp->alloc_context = alloc_depth;
exp->close = close;
exp->ctx = ctx;
blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index e39d3b23c121..5aeef60b0a5a 100644
--- a/qemu-nbd.c
+++ b/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"
@@ -527,7 +528,7 @@ int main(int argc, char **argv)
int64_t fd_size;
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' },
@@ -536,6 +537,7 @@ 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' },
@@ -577,6 +579,7 @@ int main(int argc, char **argv)
QDict *options = NULL;
const char *export_name = NULL; /* defaults to "" later for server mode */
const char *export_description = NULL;
+ bool alloc_depth = false;
const char *bitmap = NULL;
const char *tlscredsid = NULL;
bool imageOpts = false;
@@ -700,6 +703,9 @@ int main(int argc, char **argv)
readonly = true;
flags &= ~BDRV_O_RDWR;
break;
+ case 'A':
+ alloc_depth = true;
+ break;
case 'B':
bitmap = optarg;
break;
@@ -797,8 +803,8 @@ int main(int argc, char **argv)
exit(EXIT_FAILURE);
}
if (export_name || export_description || dev_offset ||
- device || disconnect || fmt || sn_id_or_name || bitmap ||
- seen_aio || seen_discard || seen_cache) {
+ device || disconnect || fmt || sn_id_or_name || alloc_depth ||
+ bitmap || seen_aio || seen_discard || seen_cache) {
error_report("List mode is incompatible with per-device settings");
exit(EXIT_FAILURE);
}
@@ -1069,8 +1075,8 @@ int main(int argc, char **argv)
fd_size -= dev_offset;
export = nbd_export_new(bs, dev_offset, fd_size, export_name,
- export_description, bitmap, readonly, shared > 1,
- nbd_export_closed, writethrough, NULL,
+ export_description, alloc_depth, bitmap, readonly,
+ shared > 1, nbd_export_closed, writethrough, NULL,
&error_fatal);
if (device) {
diff --git a/tests/qemu-iotests/309 b/tests/qemu-iotests/309
new file mode 100755
index 000000000000..fda3be9abbd2
--- /dev/null
+++ b/tests/qemu-iotests/309
@@ -0,0 +1,73 @@
+#!/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
+
+# Normal -f raw NBD block status loses access to allocation information
+$QEMU_IMG map --output=json -f qcow2 "$TEST_IMG"
+IMG="driver=nbd,server.type=unix,server.path=$nbd_unix_socket"
+nbd_server_start_unix_socket -r -f qcow2 -A "$TEST_IMG"
+$QEMU_IMG map --output=json --image-opts \
+ "$IMG" | _filter_qemu_img_map
+# But since we used -A, and use x-dirty-bitmap as a hack for reading bitmaps,
+# we can reconstruct it, by abusing block status to report:
+# NBD_STATE_DEPTH_UNALLOC => "zero":false, "data":true
+# NBD_STATE_DEPTH_LOCAL => "zero":false, "data":false
+# NBD_STATE_DEPTH_BACKING => "zero":true, "data":true
+$QEMU_IMG map --output=json --image-opts \
+ "$IMG,x-dirty-bitmap=qemu:allocation-depth" | _filter_qemu_img_map
+
+# success, all done
+echo '*** done'
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/309.out b/tests/qemu-iotests/309.out
new file mode 100644
index 000000000000..db75bb6b0df9
--- /dev/null
+++ b/tests/qemu-iotests/309.out
@@ -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
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index ff59cfd2d4c4..57182e4b3169 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -314,3 +314,4 @@
303 rw quick
304 rw quick
305 rw quick
+309 rw auto quick
--
2.28.0