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https://gitlab.com/qemu-project/qemu
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3859ad36f0
The reference owned by the user/monitor that is created when adding the export and dropped when removing it was tied to the 'exports' list in nbd/server.c. Every block export will have a user reference, so move it to the block export level and tie it to the 'block_exports' list in block/export/export.c instead. This is necessary for introducing a QMP command for removing exports. Note that exports are present in block_exports even after the user has requested shutdown. This is different from NBD's exports where exports are immediately removed on a shutdown request, even if they are still in the process of shutting down. In order to avoid that the user still interacts with an export that is shutting down (and possibly removes it a second time), we need to remember if the user actually still owns it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-20-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
349 lines
9.2 KiB
C
349 lines
9.2 KiB
C
/*
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* Serving QEMU block devices via NBD
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*
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* Copyright (c) 2012 Red Hat, Inc.
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*
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* Author: Paolo Bonzini <pbonzini@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* later. See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "sysemu/blockdev.h"
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#include "sysemu/block-backend.h"
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#include "hw/block/block.h"
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#include "qapi/error.h"
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#include "qapi/qapi-commands-block-export.h"
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#include "block/nbd.h"
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#include "io/channel-socket.h"
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#include "io/net-listener.h"
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typedef struct NBDServerData {
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QIONetListener *listener;
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QCryptoTLSCreds *tlscreds;
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char *tlsauthz;
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uint32_t max_connections;
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uint32_t connections;
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} NBDServerData;
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static NBDServerData *nbd_server;
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static bool is_qemu_nbd;
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static void nbd_update_server_watch(NBDServerData *s);
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void nbd_server_is_qemu_nbd(bool value)
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{
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is_qemu_nbd = value;
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}
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static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
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{
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nbd_client_put(client);
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assert(nbd_server->connections > 0);
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nbd_server->connections--;
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nbd_update_server_watch(nbd_server);
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}
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static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
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gpointer opaque)
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{
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nbd_server->connections++;
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nbd_update_server_watch(nbd_server);
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qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
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nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
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nbd_blockdev_client_closed);
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}
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static void nbd_update_server_watch(NBDServerData *s)
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{
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if (!s->max_connections || s->connections < s->max_connections) {
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qio_net_listener_set_client_func(s->listener, nbd_accept, NULL, NULL);
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} else {
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qio_net_listener_set_client_func(s->listener, NULL, NULL, NULL);
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}
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}
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static void nbd_server_free(NBDServerData *server)
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{
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if (!server) {
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return;
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}
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qio_net_listener_disconnect(server->listener);
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object_unref(OBJECT(server->listener));
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if (server->tlscreds) {
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object_unref(OBJECT(server->tlscreds));
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}
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g_free(server->tlsauthz);
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g_free(server);
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}
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static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
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{
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Object *obj;
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QCryptoTLSCreds *creds;
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obj = object_resolve_path_component(
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object_get_objects_root(), id);
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if (!obj) {
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error_setg(errp, "No TLS credentials with id '%s'",
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id);
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return NULL;
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}
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creds = (QCryptoTLSCreds *)
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object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
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if (!creds) {
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error_setg(errp, "Object with id '%s' is not TLS credentials",
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id);
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return NULL;
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}
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if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
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error_setg(errp,
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"Expecting TLS credentials with a server endpoint");
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return NULL;
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}
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object_ref(obj);
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return creds;
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}
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void nbd_server_start(SocketAddress *addr, const char *tls_creds,
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const char *tls_authz, uint32_t max_connections,
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Error **errp)
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{
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if (nbd_server) {
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error_setg(errp, "NBD server already running");
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return;
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}
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nbd_server = g_new0(NBDServerData, 1);
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nbd_server->max_connections = max_connections;
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nbd_server->listener = qio_net_listener_new();
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qio_net_listener_set_name(nbd_server->listener,
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"nbd-listener");
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if (qio_net_listener_open_sync(nbd_server->listener, addr, 1, errp) < 0) {
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goto error;
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}
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if (tls_creds) {
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nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp);
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if (!nbd_server->tlscreds) {
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goto error;
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}
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/* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */
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if (addr->type != SOCKET_ADDRESS_TYPE_INET) {
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error_setg(errp, "TLS is only supported with IPv4/IPv6");
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goto error;
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}
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}
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nbd_server->tlsauthz = g_strdup(tls_authz);
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nbd_update_server_watch(nbd_server);
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return;
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error:
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nbd_server_free(nbd_server);
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nbd_server = NULL;
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}
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void nbd_server_start_options(NbdServerOptions *arg, Error **errp)
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{
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nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz,
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arg->max_connections, errp);
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}
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void qmp_nbd_server_start(SocketAddressLegacy *addr,
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bool has_tls_creds, const char *tls_creds,
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bool has_tls_authz, const char *tls_authz,
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bool has_max_connections, uint32_t max_connections,
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Error **errp)
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{
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SocketAddress *addr_flat = socket_address_flatten(addr);
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nbd_server_start(addr_flat, tls_creds, tls_authz, max_connections, errp);
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qapi_free_SocketAddress(addr_flat);
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}
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int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args,
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Error **errp)
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{
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BlockExportOptionsNbd *arg = &exp_args->u.nbd;
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BlockDriverState *bs = NULL;
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AioContext *aio_context;
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int ret;
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assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
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if (!nbd_server && !is_qemu_nbd) {
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error_setg(errp, "NBD server not running");
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return -EINVAL;
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}
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if (!arg->has_name) {
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arg->name = exp_args->node_name;
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}
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if (strlen(arg->name) > NBD_MAX_STRING_SIZE) {
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error_setg(errp, "export name '%s' too long", arg->name);
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return -EINVAL;
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}
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if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
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error_setg(errp, "description '%s' too long", arg->description);
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return -EINVAL;
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}
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if (nbd_export_find(arg->name)) {
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error_setg(errp, "NBD server already has export named '%s'", arg->name);
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return -EEXIST;
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}
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bs = bdrv_lookup_bs(NULL, exp_args->node_name, errp);
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if (!bs) {
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return -ENOENT;
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}
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aio_context = bdrv_get_aio_context(bs);
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aio_context_acquire(aio_context);
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if (!arg->has_writable) {
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arg->writable = false;
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}
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if (bdrv_is_read_only(bs) && arg->writable) {
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ret = -EINVAL;
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error_setg(errp, "Cannot export read-only node as writable");
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goto out;
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}
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if (!exp_args->has_writethrough) {
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exp_args->writethrough = false;
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}
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ret = nbd_export_new(exp, bs, arg->name, arg->description, arg->bitmap,
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!arg->writable, !arg->writable,
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exp_args->writethrough, errp);
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if (ret < 0) {
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goto out;
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}
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ret = 0;
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out:
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aio_context_release(aio_context);
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return ret;
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}
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void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
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{
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BlockExport *export;
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BlockDriverState *bs;
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BlockBackend *on_eject_blk;
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BlockExportOptions *export_opts;
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bs = bdrv_lookup_bs(arg->device, arg->device, errp);
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if (!bs) {
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return;
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}
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/*
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* block-export-add would default to the node-name, but we may have to use
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* the device name as a default here for compatibility.
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*/
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if (!arg->has_name) {
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arg->name = arg->device;
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}
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export_opts = g_new(BlockExportOptions, 1);
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*export_opts = (BlockExportOptions) {
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.type = BLOCK_EXPORT_TYPE_NBD,
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.id = g_strdup(arg->name),
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.node_name = g_strdup(bdrv_get_node_name(bs)),
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.u.nbd = {
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.has_name = true,
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.name = g_strdup(arg->name),
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.has_description = arg->has_description,
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.description = g_strdup(arg->description),
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.has_writable = arg->has_writable,
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.writable = arg->writable,
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.has_bitmap = arg->has_bitmap,
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.bitmap = g_strdup(arg->bitmap),
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},
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};
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/*
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* nbd-server-add doesn't complain when a read-only device should be
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* exported as writable, but simply downgrades it. This is an error with
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* block-export-add.
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*/
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if (bdrv_is_read_only(bs)) {
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export_opts->u.nbd.has_writable = true;
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export_opts->u.nbd.writable = false;
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}
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export = blk_exp_add(export_opts, errp);
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if (!export) {
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goto fail;
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}
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/*
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* nbd-server-add removes the export when the named BlockBackend used for
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* @device goes away.
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*/
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on_eject_blk = blk_by_name(arg->device);
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if (on_eject_blk) {
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nbd_export_set_on_eject_blk(export, on_eject_blk);
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}
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fail:
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qapi_free_BlockExportOptions(export_opts);
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}
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void qmp_nbd_server_remove(const char *name,
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bool has_mode, NbdServerRemoveMode mode,
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Error **errp)
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{
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NBDExport *exp;
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AioContext *aio_context;
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if (!nbd_server) {
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error_setg(errp, "NBD server not running");
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return;
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}
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exp = nbd_export_find(name);
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if (exp == NULL) {
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error_setg(errp, "Export '%s' is not found", name);
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return;
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}
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if (!has_mode) {
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mode = NBD_SERVER_REMOVE_MODE_SAFE;
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}
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aio_context = nbd_export_aio_context(exp);
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aio_context_acquire(aio_context);
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nbd_export_remove(exp, mode, errp);
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aio_context_release(aio_context);
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}
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void qmp_nbd_server_stop(Error **errp)
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{
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if (!nbd_server) {
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error_setg(errp, "NBD server not running");
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return;
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}
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blk_exp_close_all_type(BLOCK_EXPORT_TYPE_NBD);
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nbd_server_free(nbd_server);
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nbd_server = NULL;
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}
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