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qemu/block/nbd.c
Eric Blake 216ee3657e nbd/client: Add x-dirty-bitmap to query bitmap from server 
In order to test that the NBD server is properly advertising
dirty bitmaps, we need a bare minimum client that can request
and read the context.  Since feature freeze for 3.0 is imminent,
this is the smallest workable patch, which replaces the qemu
block status report with the results of the NBD server's dirty
bitmap (making it very easy to use 'qemu-img map --output=json'
to learn where the dirty portions are).  Note that the NBD
protocol defines a dirty section with the same bit but opposite
sense that normal "base:allocation" uses to report an allocated
section; so in qemu-img map output, "data":true corresponds to
clean, "data":false corresponds to dirty.

A more complete solution that allows dirty bitmaps to be queried
at the same time as normal block status will be required before
this addition can lose the x- prefix.  Until then, the fact that
this replaces normal status with dirty status means actions
like 'qemu-img convert' will likely misbehave due to treating
dirty regions of the file as if they are unallocated.

The next patch adds an iotest to exercise this new code.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180702191458.28741-2-eblake@redhat.com>
2018-07-02 15:27:38 -05:00

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/*
* QEMU Block driver for NBD
*
* Copyright (C) 2008 Bull S.A.S.
* Author: Laurent Vivier <Laurent.Vivier@bull.net>
*
* Some parts:
* Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "nbd-client.h"
#include "block/qdict.h"
#include "qapi/error.h"
#include "qemu/uri.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qapi/qapi-visit-sockets.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qobject-output-visitor.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "qemu/cutils.h"
#define EN_OPTSTR ":exportname="
typedef struct BDRVNBDState {
NBDClientSession client;
/* For nbd_refresh_filename() */
SocketAddress *saddr;
char *export, *tlscredsid;
} BDRVNBDState;
static int nbd_parse_uri(const char *filename, QDict *options)
{
URI *uri;
const char *p;
QueryParams *qp = NULL;
int ret = 0;
bool is_unix;
uri = uri_parse(filename);
if (!uri) {
return -EINVAL;
}
/* transport */
if (!g_strcmp0(uri->scheme, "nbd")) {
is_unix = false;
} else if (!g_strcmp0(uri->scheme, "nbd+tcp")) {
is_unix = false;
} else if (!g_strcmp0(uri->scheme, "nbd+unix")) {
is_unix = true;
} else {
ret = -EINVAL;
goto out;
}
p = uri->path ? uri->path : "/";
p += strspn(p, "/");
if (p[0]) {
qdict_put_str(options, "export", p);
}
qp = query_params_parse(uri->query);
if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
ret = -EINVAL;
goto out;
}
if (is_unix) {
/* nbd+unix:///export?socket=path */
if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
ret = -EINVAL;
goto out;
}
qdict_put_str(options, "server.type", "unix");
qdict_put_str(options, "server.path", qp->p[0].value);
} else {
QString *host;
char *port_str;
/* nbd[+tcp]://host[:port]/export */
if (!uri->server) {
ret = -EINVAL;
goto out;
}
/* strip braces from literal IPv6 address */
if (uri->server[0] == '[') {
host = qstring_from_substr(uri->server, 1,
strlen(uri->server) - 2);
} else {
host = qstring_from_str(uri->server);
}
qdict_put_str(options, "server.type", "inet");
qdict_put(options, "server.host", host);
port_str = g_strdup_printf("%d", uri->port ?: NBD_DEFAULT_PORT);
qdict_put_str(options, "server.port", port_str);
g_free(port_str);
}
out:
if (qp) {
query_params_free(qp);
}
uri_free(uri);
return ret;
}
static bool nbd_has_filename_options_conflict(QDict *options, Error **errp)
{
const QDictEntry *e;
for (e = qdict_first(options); e; e = qdict_next(options, e)) {
if (!strcmp(e->key, "host") ||
!strcmp(e->key, "port") ||
!strcmp(e->key, "path") ||
!strcmp(e->key, "export") ||
strstart(e->key, "server.", NULL))
{
error_setg(errp, "Option '%s' cannot be used with a file name",
e->key);
return true;
}
}
return false;
}
static void nbd_parse_filename(const char *filename, QDict *options,
Error **errp)
{
char *file;
char *export_name;
const char *host_spec;
const char *unixpath;
if (nbd_has_filename_options_conflict(options, errp)) {
return;
}
if (strstr(filename, "://")) {
int ret = nbd_parse_uri(filename, options);
if (ret < 0) {
error_setg(errp, "No valid URL specified");
}
return;
}
file = g_strdup(filename);
export_name = strstr(file, EN_OPTSTR);
if (export_name) {
if (export_name[strlen(EN_OPTSTR)] == 0) {
goto out;
}
export_name[0] = 0; /* truncate 'file' */
export_name += strlen(EN_OPTSTR);
qdict_put_str(options, "export", export_name);
}
/* extract the host_spec - fail if it's not nbd:... */
if (!strstart(file, "nbd:", &host_spec)) {
error_setg(errp, "File name string for NBD must start with 'nbd:'");
goto out;
}
if (!*host_spec) {
goto out;
}
/* are we a UNIX or TCP socket? */
if (strstart(host_spec, "unix:", &unixpath)) {
qdict_put_str(options, "server.type", "unix");
qdict_put_str(options, "server.path", unixpath);
} else {
InetSocketAddress *addr = g_new(InetSocketAddress, 1);
if (inet_parse(addr, host_spec, errp)) {
goto out_inet;
}
qdict_put_str(options, "server.type", "inet");
qdict_put_str(options, "server.host", addr->host);
qdict_put_str(options, "server.port", addr->port);
out_inet:
qapi_free_InetSocketAddress(addr);
}
out:
g_free(file);
}
static bool nbd_process_legacy_socket_options(QDict *output_options,
QemuOpts *legacy_opts,
Error **errp)
{
const char *path = qemu_opt_get(legacy_opts, "path");
const char *host = qemu_opt_get(legacy_opts, "host");
const char *port = qemu_opt_get(legacy_opts, "port");
const QDictEntry *e;
if (!path && !host && !port) {
return true;
}
for (e = qdict_first(output_options); e; e = qdict_next(output_options, e))
{
if (strstart(e->key, "server.", NULL)) {
error_setg(errp, "Cannot use 'server' and path/host/port at the "
"same time");
return false;
}
}
if (path && host) {
error_setg(errp, "path and host may not be used at the same time");
return false;
} else if (path) {
if (port) {
error_setg(errp, "port may not be used without host");
return false;
}
qdict_put_str(output_options, "server.type", "unix");
qdict_put_str(output_options, "server.path", path);
} else if (host) {
qdict_put_str(output_options, "server.type", "inet");
qdict_put_str(output_options, "server.host", host);
qdict_put_str(output_options, "server.port",
port ?: stringify(NBD_DEFAULT_PORT));
}
return true;
}
static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
Error **errp)
{
SocketAddress *saddr = NULL;
QDict *addr = NULL;
Visitor *iv = NULL;
Error *local_err = NULL;
qdict_extract_subqdict(options, &addr, "server.");
if (!qdict_size(addr)) {
error_setg(errp, "NBD server address missing");
goto done;
}
iv = qobject_input_visitor_new_flat_confused(addr, errp);
if (!iv) {
goto done;
}
visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto done;
}
done:
qobject_unref(addr);
visit_free(iv);
return saddr;
}
NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
return &s->client;
}
static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
Error **errp)
{
QIOChannelSocket *sioc;
Error *local_err = NULL;
sioc = qio_channel_socket_new();
qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
qio_channel_socket_connect_sync(sioc,
saddr,
&local_err);
if (local_err) {
object_unref(OBJECT(sioc));
error_propagate(errp, local_err);
return NULL;
}
qio_channel_set_delay(QIO_CHANNEL(sioc), false);
return sioc;
}
static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
{
Object *obj;
QCryptoTLSCreds *creds;
obj = object_resolve_path_component(
object_get_objects_root(), id);
if (!obj) {
error_setg(errp, "No TLS credentials with id '%s'",
id);
return NULL;
}
creds = (QCryptoTLSCreds *)
object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
if (!creds) {
error_setg(errp, "Object with id '%s' is not TLS credentials",
id);
return NULL;
}
if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
error_setg(errp,
"Expecting TLS credentials with a client endpoint");
return NULL;
}
object_ref(obj);
return creds;
}
static QemuOptsList nbd_runtime_opts = {
.name = "nbd",
.head = QTAILQ_HEAD_INITIALIZER(nbd_runtime_opts.head),
.desc = {
{
.name = "host",
.type = QEMU_OPT_STRING,
.help = "TCP host to connect to",
},
{
.name = "port",
.type = QEMU_OPT_STRING,
.help = "TCP port to connect to",
},
{
.name = "path",
.type = QEMU_OPT_STRING,
.help = "Unix socket path to connect to",
},
{
.name = "export",
.type = QEMU_OPT_STRING,
.help = "Name of the NBD export to open",
},
{
.name = "tls-creds",
.type = QEMU_OPT_STRING,
.help = "ID of the TLS credentials to use",
},
{
.name = "x-dirty-bitmap",
.type = QEMU_OPT_STRING,
.help = "experimental: expose named dirty bitmap in place of "
"block status",
},
{ /* end of list */ }
},
};
static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVNBDState *s = bs->opaque;
QemuOpts *opts = NULL;
Error *local_err = NULL;
QIOChannelSocket *sioc = NULL;
QCryptoTLSCreds *tlscreds = NULL;
const char *hostname = NULL;
int ret = -EINVAL;
opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto error;
}
/* Translate @host, @port, and @path to a SocketAddress */
if (!nbd_process_legacy_socket_options(options, opts, errp)) {
goto error;
}
/* Pop the config into our state object. Exit if invalid. */
s->saddr = nbd_config(s, options, errp);
if (!s->saddr) {
goto error;
}
s->export = g_strdup(qemu_opt_get(opts, "export"));
s->tlscredsid = g_strdup(qemu_opt_get(opts, "tls-creds"));
if (s->tlscredsid) {
tlscreds = nbd_get_tls_creds(s->tlscredsid, errp);
if (!tlscreds) {
goto error;
}
/* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */
if (s->saddr->type != SOCKET_ADDRESS_TYPE_INET) {
error_setg(errp, "TLS only supported over IP sockets");
goto error;
}
hostname = s->saddr->u.inet.host;
}
/* establish TCP connection, return error if it fails
* TODO: Configurable retry-until-timeout behaviour.
*/
sioc = nbd_establish_connection(s->saddr, errp);
if (!sioc) {
ret = -ECONNREFUSED;
goto error;
}
/* NBD handshake */
ret = nbd_client_init(bs, sioc, s->export, tlscreds, hostname,
qemu_opt_get(opts, "x-dirty-bitmap"), errp);
error:
if (sioc) {
object_unref(OBJECT(sioc));
}
if (tlscreds) {
object_unref(OBJECT(tlscreds));
}
if (ret < 0) {
qapi_free_SocketAddress(s->saddr);
g_free(s->export);
g_free(s->tlscredsid);
}
qemu_opts_del(opts);
return ret;
}
static int nbd_co_flush(BlockDriverState *bs)
{
return nbd_client_co_flush(bs);
}
static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
{
NBDClientSession *s = nbd_get_client_session(bs);
uint32_t min = s->info.min_block;
uint32_t max = MIN_NON_ZERO(NBD_MAX_BUFFER_SIZE, s->info.max_block);
bs->bl.request_alignment = min ? min : BDRV_SECTOR_SIZE;
bs->bl.max_pdiscard = max;
bs->bl.max_pwrite_zeroes = max;
bs->bl.max_transfer = max;
if (s->info.opt_block &&
s->info.opt_block > bs->bl.opt_transfer) {
bs->bl.opt_transfer = s->info.opt_block;
}
}
static void nbd_close(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
nbd_client_close(bs);
qapi_free_SocketAddress(s->saddr);
g_free(s->export);
g_free(s->tlscredsid);
}
static int64_t nbd_getlength(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
return s->client.info.size;
}
static void nbd_detach_aio_context(BlockDriverState *bs)
{
nbd_client_detach_aio_context(bs);
}
static void nbd_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
nbd_client_attach_aio_context(bs, new_context);
}
static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
{
BDRVNBDState *s = bs->opaque;
QDict *opts = qdict_new();
QObject *saddr_qdict;
Visitor *ov;
const char *host = NULL, *port = NULL, *path = NULL;
if (s->saddr->type == SOCKET_ADDRESS_TYPE_INET) {
const InetSocketAddress *inet = &s->saddr->u.inet;
if (!inet->has_ipv4 && !inet->has_ipv6 && !inet->has_to) {
host = inet->host;
port = inet->port;
}
} else if (s->saddr->type == SOCKET_ADDRESS_TYPE_UNIX) {
path = s->saddr->u.q_unix.path;
} /* else can't represent as pseudo-filename */
qdict_put_str(opts, "driver", "nbd");
if (path && s->export) {
snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd+unix:///%s?socket=%s", s->export, path);
} else if (path && !s->export) {
snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd+unix://?socket=%s", path);
} else if (host && s->export) {
snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd://%s:%s/%s", host, port, s->export);
} else if (host && !s->export) {
snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"nbd://%s:%s", host, port);
}
ov = qobject_output_visitor_new(&saddr_qdict);
visit_type_SocketAddress(ov, NULL, &s->saddr, &error_abort);
visit_complete(ov, &saddr_qdict);
visit_free(ov);
qdict_put_obj(opts, "server", saddr_qdict);
if (s->export) {
qdict_put_str(opts, "export", s->export);
}
if (s->tlscredsid) {
qdict_put_str(opts, "tls-creds", s->tlscredsid);
}
qdict_flatten(opts);
bs->full_open_options = opts;
}
static BlockDriver bdrv_nbd = {
.format_name = "nbd",
.protocol_name = "nbd",
.instance_size = sizeof(BDRVNBDState),
.bdrv_parse_filename = nbd_parse_filename,
.bdrv_file_open = nbd_open,
.bdrv_co_preadv = nbd_client_co_preadv,
.bdrv_co_pwritev = nbd_client_co_pwritev,
.bdrv_co_pwrite_zeroes = nbd_client_co_pwrite_zeroes,
.bdrv_close = nbd_close,
.bdrv_co_flush_to_os = nbd_co_flush,
.bdrv_co_pdiscard = nbd_client_co_pdiscard,
.bdrv_refresh_limits = nbd_refresh_limits,
.bdrv_getlength = nbd_getlength,
.bdrv_detach_aio_context = nbd_detach_aio_context,
.bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_co_block_status = nbd_client_co_block_status,
};
static BlockDriver bdrv_nbd_tcp = {
.format_name = "nbd",
.protocol_name = "nbd+tcp",
.instance_size = sizeof(BDRVNBDState),
.bdrv_parse_filename = nbd_parse_filename,
.bdrv_file_open = nbd_open,
.bdrv_co_preadv = nbd_client_co_preadv,
.bdrv_co_pwritev = nbd_client_co_pwritev,
.bdrv_co_pwrite_zeroes = nbd_client_co_pwrite_zeroes,
.bdrv_close = nbd_close,
.bdrv_co_flush_to_os = nbd_co_flush,
.bdrv_co_pdiscard = nbd_client_co_pdiscard,
.bdrv_refresh_limits = nbd_refresh_limits,
.bdrv_getlength = nbd_getlength,
.bdrv_detach_aio_context = nbd_detach_aio_context,
.bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_co_block_status = nbd_client_co_block_status,
};
static BlockDriver bdrv_nbd_unix = {
.format_name = "nbd",
.protocol_name = "nbd+unix",
.instance_size = sizeof(BDRVNBDState),
.bdrv_parse_filename = nbd_parse_filename,
.bdrv_file_open = nbd_open,
.bdrv_co_preadv = nbd_client_co_preadv,
.bdrv_co_pwritev = nbd_client_co_pwritev,
.bdrv_co_pwrite_zeroes = nbd_client_co_pwrite_zeroes,
.bdrv_close = nbd_close,
.bdrv_co_flush_to_os = nbd_co_flush,
.bdrv_co_pdiscard = nbd_client_co_pdiscard,
.bdrv_refresh_limits = nbd_refresh_limits,
.bdrv_getlength = nbd_getlength,
.bdrv_detach_aio_context = nbd_detach_aio_context,
.bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_co_block_status = nbd_client_co_block_status,
};
static void bdrv_nbd_init(void)
{
bdrv_register(&bdrv_nbd);
bdrv_register(&bdrv_nbd_tcp);
bdrv_register(&bdrv_nbd_unix);
}
block_init(bdrv_nbd_init);
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