qemu-nbd: Add --bitmap=NAME option

Having to fire up qemu, then use QMP commands for nbd-server-start
and nbd-server-add, just to expose a persistent dirty bitmap, is
rather tedious.  Make it possible to expose a dirty bitmap using
just qemu-nbd (of course, for now this only works when qemu-nbd is
visiting a BDS formatted as qcow2).

Of course, any good feature also needs unit testing, so expand
iotest 223 to cover it.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190111194720.15671-9-eblake@redhat.com>
This commit is contained in:
Eric Blake 2019-01-11 13:47:20 -06:00
parent 678ba275c7
commit 636192c4b6
4 changed files with 40 additions and 4 deletions

View File

@ -95,6 +95,7 @@ static void usage(const char *name)
"Exposing part of the image:\n"
" -o, --offset=OFFSET offset into the image\n"
" -P, --partition=NUM only expose partition NUM\n"
" -B, --bitmap=NAME expose a persistent dirty bitmap\n"
"\n"
"General purpose options:\n"
" --object type,id=ID,... define an object such as 'secret' for providing\n"
@ -509,7 +510,7 @@ int main(int argc, char **argv)
off_t fd_size;
QemuOpts *sn_opts = NULL;
const char *sn_id_or_name = NULL;
const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:";
const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:";
struct option lopt[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
@ -519,6 +520,7 @@ int main(int argc, char **argv)
{ "offset", required_argument, NULL, 'o' },
{ "read-only", no_argument, NULL, 'r' },
{ "partition", required_argument, NULL, 'P' },
{ "bitmap", required_argument, NULL, 'B' },
{ "connect", required_argument, NULL, 'c' },
{ "disconnect", no_argument, NULL, 'd' },
{ "snapshot", no_argument, NULL, 's' },
@ -558,6 +560,7 @@ int main(int argc, char **argv)
QDict *options = NULL;
const char *export_name = ""; /* Default export name */
const char *export_description = NULL;
const char *bitmap = NULL;
const char *tlscredsid = NULL;
bool imageOpts = false;
bool writethrough = true;
@ -695,6 +698,9 @@ int main(int argc, char **argv)
exit(EXIT_FAILURE);
}
break;
case 'B':
bitmap = optarg;
break;
case 'k':
sockpath = optarg;
if (sockpath[0] != '/') {
@ -1016,7 +1022,7 @@ int main(int argc, char **argv)
}
export = nbd_export_new(bs, dev_offset, fd_size, export_name,
export_description, NULL, nbdflags,
export_description, bitmap, nbdflags,
nbd_export_closed, writethrough, NULL,
&error_fatal);

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@ -45,6 +45,10 @@ auto-detecting
Export the disk as read-only
@item -P, --partition=@var{num}
Only expose partition @var{num}
@item -B, --bitmap=@var{name}
If @var{filename} has a qcow2 persistent bitmap @var{name}, expose
that bitmap via the ``qemu:dirty-bitmap:@var{name}'' context
accessible through NBD_OPT_SET_META_CONTEXT.
@item -s, --snapshot
Use @var{filename} as an external snapshot, create a temporary
file with backing_file=@var{filename}, redirect the write to

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@ -25,6 +25,7 @@ status=1 # failure is the default!
_cleanup()
{
nbd_server_stop
_cleanup_test_img
_cleanup_qemu
rm -f "$TEST_DIR/nbd"
@ -35,6 +36,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
. ./common.rc
. ./common.filter
. ./common.qemu
. ./common.nbd
_supported_fmt qcow2
_supported_proto file # uses NBD as well
@ -163,7 +165,7 @@ $QEMU_IMG map --output=json --image-opts \
"$IMG,x-dirty-bitmap=qemu:dirty-bitmap:b2" | _filter_qemu_img_map
echo
echo "=== End NBD server ==="
echo "=== End qemu NBD server ==="
echo
_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-remove",
@ -176,6 +178,20 @@ _send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "return"
_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "error" # Again
_send_qemu_cmd $QEMU_HANDLE '{"execute":"quit"}' "return"
echo
echo "=== Use qemu-nbd as server ==="
echo
nbd_server_start_unix_socket -r -f $IMGFMT -B b "$TEST_IMG"
IMG="driver=nbd,server.type=unix,server.path=$nbd_unix_socket"
$QEMU_IMG map --output=json --image-opts \
"$IMG,x-dirty-bitmap=qemu:dirty-bitmap:b" | _filter_qemu_img_map
nbd_server_start_unix_socket -f $IMGFMT -B b2 "$TEST_IMG"
IMG="driver=nbd,server.type=unix,server.path=$nbd_unix_socket"
$QEMU_IMG map --output=json --image-opts \
"$IMG,x-dirty-bitmap=qemu:dirty-bitmap:b2" | _filter_qemu_img_map
# success, all done
echo '*** done'
rm -f $seq.full

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@ -61,7 +61,7 @@ read 2097152/2097152 bytes at offset 2097152
{ "start": 1024, "length": 2096128, "depth": 0, "zero": false, "data": true},
{ "start": 2097152, "length": 2097152, "depth": 0, "zero": false, "data": false}]
=== End NBD server ===
=== End qemu NBD server ===
{"return": {}}
{"return": {}}
@ -69,4 +69,14 @@ read 2097152/2097152 bytes at offset 2097152
{"return": {}}
{"error": {"class": "GenericError", "desc": "NBD server not running"}}
{"return": {}}
=== Use qemu-nbd as server ===
[{ "start": 0, "length": 65536, "depth": 0, "zero": false, "data": false},
{ "start": 65536, "length": 2031616, "depth": 0, "zero": false, "data": true},
{ "start": 2097152, "length": 2097152, "depth": 0, "zero": false, "data": false}]
[{ "start": 0, "length": 512, "depth": 0, "zero": false, "data": true},
{ "start": 512, "length": 512, "depth": 0, "zero": false, "data": false},
{ "start": 1024, "length": 2096128, "depth": 0, "zero": false, "data": true},
{ "start": 2097152, "length": 2097152, "depth": 0, "zero": false, "data": false}]
*** done