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Re: [Xen-devel] [PATCH 20/27] tools/libxl: Infrastructure for writing a v2 stream
On 06/15/2015 09:44 PM, Andrew Cooper wrote:
[...]
+
+static void stream_success(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void stream_failed(libxl__egc *egc,
+ libxl__stream_write_state *stream, int ret);
+static void stream_done(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+
+static void check_stream_finished(libxl__egc *egc,
+ libxl__domain_suspend_state *dcs,
s/dcs/dss/
+ int rc, const char *what);
+
+/* Event callbacks for plain VM. */
+static void stream_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void libxc_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+/* libxl__xc_domain_save_done() lives here, event-order wise. */
+static void write_toolstack_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void toolstack_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void write_emulator_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void emulator_body_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void emulator_padding_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+static void write_end_record(libxl__egc *egc,
+ libxl__stream_write_state *stream);
+static void end_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval);
+
+void libxl__stream_write_start(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_hdr hdr = { 0 };
+ int ret = 0;
+
+ assert(!stream->running);
+ stream->running = true;
+
+ memset(dc, 0, sizeof(*dc));
+ dc->readwhat = "";
+ dc->copywhat = "suspend header";
+ dc->writewhat = "save/migration stream";
+ dc->ao = ao;
+ dc->readfd = -1;
+ dc->writefd = stream->fd;
+ dc->maxsz = INT_MAX;
+ dc->bytes_to_read = INT_MAX;
+ dc->callback = stream_header_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ hdr.ident = htobe64(RESTORE_STREAM_IDENT);
+ hdr.version = htobe32(RESTORE_STREAM_VERSION);
+ hdr.options = htobe32(0);
+
+ libxl__datacopier_prefixdata(egc, dc, &hdr, sizeof(hdr));
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+void libxl__stream_write_abort(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc)
+{
+ stream_failed(egc, stream, rc);
+}
+
+static void stream_success(libxl__egc *egc, libxl__stream_write_state *stream)
+{
+ stream->rc = 0;
+ stream->running = false;
+
+ stream_done(egc, stream);
+}
+
+static void stream_failed(libxl__egc *egc,
+ libxl__stream_write_state *stream, int rc)
+{
+ assert(rc);
+ stream->rc = rc;
+
+ if (stream->running) {
+ stream->running = false;
+ stream_done(egc, stream);
+ }
+}
+
+static void stream_done(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+
+ assert(!stream->running);
+
+ check_stream_finished(egc, dss, stream->rc, "stream");
+}
+
+static void check_stream_finished(libxl__egc *egc,
+ libxl__domain_suspend_state *dss,
+ int rc, const char *what)
+{
+ libxl__stream_write_state *stream = &dss->sws;
+ STATE_AO_GC(dss->ao);
+
+ LOG(INFO, "Task '%s' joining (rc %d)", what, rc);
+
+ if (rc && !stream->joined_rc) {
+ bool skip = false;
+ /* First reported failure from joining tasks. Tear everything down */
+ stream->joined_rc = rc;
+
+ if (libxl__stream_write_inuse(&dss->sws)) {
+ skip = true;
+ libxl__stream_write_abort(egc, &dss->sws, rc);
+ }
+
+ if (libxl__save_helper_inuse(&dss->shs)) {
+ skip = true;
+ libxl__save_helper_abort(egc, &dss->shs);
+ }
+
+ /* There is at least one more active task to join - wait for its
+ callback */
+ if ( skip )
+ return;
+ }
+
+ if (libxl__stream_write_inuse(&dss->sws))
+ LOG(DEBUG, "stream still in use");
+ else if (libxl__save_helper_inuse(&dss->shs))
+ LOG(DEBUG, "save/restore still in use");
+ else {
+ LOG(INFO, "Join complete: result %d", stream->joined_rc);
+ stream->completion_callback(egc, dss, stream->joined_rc);
+ }
+}
+
+static void stream_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_LIBXC_CONTEXT, 0 };
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ dc->copywhat = "suspend footer";
+ dc->writewhat = "save/migration stream";
+ dc->callback = libxc_header_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void libxc_header_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ libxl__xc_domain_save(egc, dss);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void __attribute__((used))
+will_be_libxl__xc_domain_save_done(libxl__egc *egc, void *dss_void,
+ int rc, int retval, int errnoval)
+{
+ libxl__domain_suspend_state *dss = dss_void;
+ libxl__stream_write_state *stream = &dss->sws;
+ STATE_AO_GC(dss->ao);
+
+ if (rc)
+ goto err;
+
+ if (retval) {
+ LOGEV(ERROR, errnoval, "saving domain: %s",
+ dss->guest_responded ?
+ "domain responded to suspend request" :
+ "domain did not respond to suspend request");
+ if ( !dss->guest_responded )
+ rc = ERROR_GUEST_TIMEDOUT;
+ else
+ rc = ERROR_FAIL;
+ goto err;
+ }
+
+ write_toolstack_record(egc, stream);
+ return;
+
+ err:
+ assert(rc);
+ check_stream_finished(egc, dss, rc, "save/restore helper");
+}
+
+static void write_toolstack_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_XENSTORE_DATA, 0 };
+ int ret = 0;
+ uint8_t *toolstack_buf = NULL; /* We must free this. */
+ uint32_t toolstack_len, padding_len;
+
+ ret = libxl__toolstack_save(dss->domid, &toolstack_buf,
+ &toolstack_len, dss);
+ if (ret)
+ goto err;
+
+ dc->copywhat = "toolstack record";
+ dc->writewhat = "save/migration stream";
+ dc->callback = toolstack_record_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ rec.length = toolstack_len;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ libxl__datacopier_prefixdata(egc, dc, toolstack_buf, toolstack_len);
+
+ padding_len = ROUNDUP(rec.length, REC_ALIGN_ORDER) - rec.length;
+ if (padding_len)
+ libxl__datacopier_prefixdata(egc, dc, zero_padding, padding_len);
+
+ free(toolstack_buf);
+ return;
+
+ err:
+ assert(ret);
+ free(toolstack_buf);
+ stream_failed(egc, stream, ret);
+}
+
+static void toolstack_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ if (dss->type == LIBXL_DOMAIN_TYPE_HVM)
+ write_emulator_record(egc, stream);
+ else
+ write_end_record(egc, stream);
+
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void write_emulator_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__domain_suspend_state *dss = CONTAINER_OF(stream, *dss, sws);
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_EMULATOR_CONTEXT, 0 };
+ struct libxl_sr_emulator_hdr ehdr = { 0 };
+ struct stat st;
+ int ret = 0;
+ uint32_t qemu_state_len;
+
+ assert(dss->type == LIBXL_DOMAIN_TYPE_HVM);
+
+ /* Convenience aliases */
+ const char *const filename = dss->dm_savefile;
+ const uint32_t domid = dss->domid;
+
+ switch(libxl__device_model_version_running(gc, domid)) {
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
+ ehdr.id = EMULATOR_QEMU_TRADITIONAL;
+ break;
+
+ case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
+ ehdr.id = EMULATOR_QEMU_UPSTREAM;
+ break;
+
+ default:
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ ret = libxl__domain_suspend_device_model(gc, dss);
+ if (ret)
+ goto err;
+
+ dc->readwhat = GCSPRINTF("qemu save file %s", filename);
+ dc->copywhat = "emulator record";
+ dc->writewhat = "save/migration stream";
+ dc->callback = emulator_body_done;
+
+ dc->readfd = open(filename, O_RDONLY);
+ if (dc->readfd < 0) {
+ LOGE(ERROR, "unable to open %s", dc->readwhat);
+ goto err;
+ }
+
+ if (fstat(dc->readfd, &st))
+ {
+ LOGE(ERROR, "unable to fstat %s", dc->readwhat);
+ goto err;
+ }
+
+ if (!S_ISREG(st.st_mode)) {
+ LOG(ERROR, "%s is not a plain file!", dc->readwhat);
+ goto err;
+ }
+
+ qemu_state_len = st.st_size;
+ rec.length = qemu_state_len + sizeof(ehdr);
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ libxl__datacopier_prefixdata(egc, dc, &ehdr, sizeof(ehdr));
+
+ stream->padding = ROUNDUP(qemu_state_len, REC_ALIGN_ORDER) -
qemu_state_len;
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void emulator_body_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ dc->readwhat = "";
+ dc->readfd = -1;
+
+ if (stream->padding) {
+ assert(stream->padding < (1U << REC_ALIGN_ORDER));
+
+ dc->copywhat = "emulator padding";
+ dc->writewhat = "save/migration stream";
+ dc->callback = emulator_padding_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, zero_padding, stream->padding);
+ return;
+ }
+
+ emulator_padding_done(egc, dc, 0, 0);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void emulator_padding_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ write_end_record(egc, stream);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void write_end_record(libxl__egc *egc,
+ libxl__stream_write_state *stream)
+{
+ libxl__datacopier_state *dc = &stream->dc;
+ STATE_AO_GC(stream->ao);
+ struct libxl_sr_rec_hdr rec = { REC_TYPE_END, 0 };
+ int ret = 0;
+
+ dc->copywhat = "suspend footer";
+ dc->writewhat = "save/migration stream";
+ dc->callback = end_record_done;
+
+ ret = libxl__datacopier_start(dc);
+ if (ret)
+ goto err;
+
+ libxl__datacopier_prefixdata(egc, dc, &rec, sizeof(rec));
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+static void end_record_done(libxl__egc *egc,
+ libxl__datacopier_state *dc,
+ int onwrite, int errnoval)
+{
+ libxl__stream_write_state *stream = CONTAINER_OF(dc, *stream, dc);
+ STATE_AO_GC(stream->ao);
+ int ret = 0;
+
+ if (onwrite || errnoval) {
+ ret = ERROR_FAIL;
+ goto err;
+ }
+
+ stream_success(egc, stream);
+ return;
+
+ err:
+ assert(ret);
+ stream_failed(egc, stream, ret);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
Thanks,
Yang.
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