+/* nbd_negotiate_simple_meta_context:
+ * Request the server to set the meta context for export @info->name
+ * using @info->x_dirty_bitmap with a fallback to "base:allocation",
+ * setting @info->context_id to the resulting id. Fail if the server
+ * responds with more than one context or with a context different
+ * than the query.
+ * return 1 for successful negotiation,
+ * 0 if operation is unsupported,
+ * -1 with errp set for any other error
+ */
+static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,
+ NBDExportInfo *info,
+ Error **errp)
+{
+ /*
+ * TODO: Removing the x_dirty_bitmap hack will mean refactoring
+ * this function to request and store ids for multiple contexts
+ * (both base:allocation and a dirty bitmap), at which point this
+ * function should lose the term _simple.
+ */
+ int ret;
+ NBDOptionReply reply;
+ const char *context = info->x_dirty_bitmap ?: "base:allocation";
+ bool received = false;
+ uint32_t export_len = strlen(info->name);
+ uint32_t context_len = strlen(context);
+ uint32_t data_len = sizeof(export_len) + export_len +
+ sizeof(uint32_t) + /* number of queries */
+ sizeof(context_len) + context_len;
+ char *data = g_malloc(data_len);
+ char *p = data;
+
+ trace_nbd_opt_meta_request(context, info->name);
+ stl_be_p(p, export_len);
+ memcpy(p += sizeof(export_len), info->name, export_len);
+ stl_be_p(p += export_len, 1);
+ stl_be_p(p += sizeof(uint32_t), context_len);
+ memcpy(p += sizeof(context_len), context, context_len);
+
+ ret = nbd_send_option_request(ioc, NBD_OPT_SET_META_CONTEXT, data_len, data,
+ errp);
+ g_free(data);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply,
+ errp) < 0)
+ {
+ return -1;
+ }
+
+ ret = nbd_handle_reply_err(ioc, &reply, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+
+ if (reply.type == NBD_REP_META_CONTEXT) {
+ char *name;
+
+ if (reply.length != sizeof(info->context_id) + context_len) {
+ error_setg(errp, "Failed to negotiate meta context '%s', server "
+ "answered with unexpected length %" PRIu32, context,
+ reply.length);
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+
+ if (nbd_read(ioc, &info->context_id, sizeof(info->context_id),
+ errp) < 0) {
+ return -1;
+ }
+ info->context_id = be32_to_cpu(info->context_id);
+
+ reply.length -= sizeof(info->context_id);
+ name = g_malloc(reply.length + 1);
+ if (nbd_read(ioc, name, reply.length, errp) < 0) {
+ g_free(name);
+ return -1;
+ }
+ name[reply.length] = '\0';
+ if (strcmp(context, name)) {
+ error_setg(errp, "Failed to negotiate meta context '%s', server "
+ "answered with different context '%s'", context,
+ name);
+ g_free(name);
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ g_free(name);
+
+ trace_nbd_opt_meta_reply(context, info->context_id);
+ received = true;
+
+ /* receive NBD_REP_ACK */
+ if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply,
+ errp) < 0)
+ {
+ return -1;
+ }
+
+ ret = nbd_handle_reply_err(ioc, &reply, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+ }
+
+ if (reply.type != NBD_REP_ACK) {
+ error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)",
+ reply.type, nbd_rep_lookup(reply.type),
+ NBD_REP_ACK, nbd_rep_lookup(NBD_REP_ACK));
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ if (reply.length) {
+ error_setg(errp, "Unexpected length to ACK response");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+
+ return received;
+}
projects / qemu.git / blobdiff