--- /dev/null
+/*
+ * NBD engine
+ *
+ * IO engine that talks to an NBD server.
+ *
+ * Copyright (C) 2019 Red Hat Inc.
+ * Written by Richard W.M. Jones <rjones@redhat.com>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include <libnbd.h>
+
+#include "../fio.h"
+#include "../optgroup.h"
+
+/* Actually this differs across servers, but for nbdkit ... */
+#define NBD_MAX_REQUEST_SIZE (64 * 1024 * 1024)
+
+/* Storage for the NBD handle. */
+struct nbd_data {
+ struct nbd_handle *nbd;
+ int debug;
+
+ /* The list of completed io_u structs. */
+ struct io_u **completed;
+ size_t nr_completed;
+};
+
+/* Options. */
+struct nbd_options {
+ void *padding;
+ char *uri;
+};
+
+static struct fio_option options[] = {
+ {
+ .name = "uri",
+ .lname = "NBD URI",
+ .help = "Name of NBD URI",
+ .category = FIO_OPT_C_ENGINE,
+ .group = FIO_OPT_G_NBD,
+ .type = FIO_OPT_STR_STORE,
+ .off1 = offsetof(struct nbd_options, uri),
+ },
+ {
+ .name = NULL,
+ },
+};
+
+/* Alocates nbd_data. */
+static int nbd_setup(struct thread_data *td)
+{
+ struct nbd_data *nbd_data;
+ struct nbd_options *o = td->eo;
+ struct fio_file *f;
+ int r;
+ int64_t size;
+
+ nbd_data = calloc(1, sizeof(*nbd_data));
+ if (!nbd_data) {
+ td_verror(td, errno, "calloc");
+ return 1;
+ }
+ td->io_ops_data = nbd_data;
+
+ /* Pretend to deal with files. See engines/rbd.c */
+ if (!td->files_index) {
+ add_file(td, "nbd", 0, 0);
+ td->o.nr_files = td->o.nr_files ? : 1;
+ td->o.open_files++;
+ }
+ f = td->files[0];
+
+ nbd_data->nbd = nbd_create();
+ if (!nbd_data->nbd) {
+ log_err("fio: nbd_create: %s\n", nbd_get_error());
+ return 1;
+ }
+
+ /* Get the debug flag which can be set through LIBNBD_DEBUG=1. */
+ nbd_data->debug = nbd_get_debug(nbd_data->nbd);
+
+ /* Connect synchronously here so we can check for the size and
+ * in future other properties of the server.
+ */
+ if (!o->uri) {
+ log_err("fio: nbd: uri parameter was not specified\n");
+ return 1;
+ }
+ r = nbd_connect_uri(nbd_data->nbd, o->uri);
+ if (r == -1) {
+ log_err("fio: nbd_connect_uri: %s\n", nbd_get_error());
+ return 1;
+ }
+ size = nbd_get_size(nbd_data->nbd);
+ if (size == -1) {
+ log_err("fio: nbd_get_size: %s\n", nbd_get_error());
+ return 1;
+ }
+
+ f->real_file_size = size;
+
+ nbd_close (nbd_data->nbd);
+ nbd_data->nbd = NULL;
+
+ return 0;
+}
+
+/* Closes socket and frees nbd_data -- the opposite of nbd_setup. */
+static void nbd_cleanup(struct thread_data *td)
+{
+ struct nbd_data *nbd_data = td->io_ops_data;
+
+ if (nbd_data) {
+ if (nbd_data->nbd)
+ nbd_close(nbd_data->nbd);
+ free(nbd_data);
+ }
+}
+
+/* Connect to the server from each thread. */
+static int nbd_init(struct thread_data *td)
+{
+ struct nbd_options *o = td->eo;
+ struct nbd_data *nbd_data = td->io_ops_data;
+ int r;
+
+ if (!o->uri) {
+ log_err("fio: nbd: uri parameter was not specified\n");
+ return 1;
+ }
+
+ nbd_data->nbd = nbd_create();
+ if (!nbd_data->nbd) {
+ log_err("fio: nbd_create: %s\n", nbd_get_error());
+ return 1;
+ }
+ /* This is actually a synchronous connect and handshake. */
+ r = nbd_connect_uri(nbd_data->nbd, o->uri);
+ if (r == -1) {
+ log_err("fio: nbd_connect_uri: %s\n", nbd_get_error());
+ return 1;
+ }
+
+ log_info("fio: connected to NBD server\n");
+ return 0;
+}
+
+/* A command in flight has been completed. */
+static int cmd_completed (unsigned valid_flag, void *vp, int *error)
+{
+ struct io_u *io_u;
+ struct nbd_data *nbd_data;
+ struct io_u **completed;
+
+ if (!(valid_flag & LIBNBD_CALLBACK_VALID))
+ return 0;
+
+ io_u = vp;
+ nbd_data = io_u->engine_data;
+
+ if (nbd_data->debug)
+ log_info("fio: nbd: command completed\n");
+
+ if (*error != 0)
+ io_u->error = *error;
+ else
+ io_u->error = 0;
+
+ /* Add this completion to the list so it can be picked up
+ * later by ->event.
+ */
+ completed = realloc(nbd_data->completed,
+ sizeof(struct io_u *) *
+ (nbd_data->nr_completed+1));
+ if (completed == NULL) {
+ io_u->error = errno;
+ return 0;
+ }
+
+ nbd_data->completed = completed;
+ nbd_data->completed[nbd_data->nr_completed] = io_u;
+ nbd_data->nr_completed++;
+
+ return 0;
+}
+
+/* Begin read or write request. */
+static enum fio_q_status nbd_queue(struct thread_data *td,
+ struct io_u *io_u)
+{
+ struct nbd_data *nbd_data = td->io_ops_data;
+ int r;
+
+ fio_ro_check(td, io_u);
+
+ io_u->engine_data = nbd_data;
+
+ if (io_u->ddir == DDIR_WRITE || io_u->ddir == DDIR_READ)
+ assert(io_u->xfer_buflen <= NBD_MAX_REQUEST_SIZE);
+
+ switch (io_u->ddir) {
+ case DDIR_READ:
+ r = nbd_aio_pread_callback(nbd_data->nbd,
+ io_u->xfer_buf, io_u->xfer_buflen,
+ io_u->offset,
+ cmd_completed, io_u,
+ 0);
+ break;
+ case DDIR_WRITE:
+ r = nbd_aio_pwrite_callback(nbd_data->nbd,
+ io_u->xfer_buf, io_u->xfer_buflen,
+ io_u->offset,
+ cmd_completed, io_u,
+ 0);
+ break;
+ case DDIR_TRIM:
+ r = nbd_aio_trim_callback(nbd_data->nbd, io_u->xfer_buflen,
+ io_u->offset,
+ cmd_completed, io_u,
+ 0);
+ break;
+ case DDIR_SYNC:
+ /* XXX We could probably also handle
+ * DDIR_SYNC_FILE_RANGE with a bit of effort.
+ */
+ r = nbd_aio_flush_callback(nbd_data->nbd,
+ cmd_completed, io_u,
+ 0);
+ break;
+ default:
+ io_u->error = EINVAL;
+ return FIO_Q_COMPLETED;
+ }
+
+ if (r == -1) {
+ /* errno is optional information on libnbd error path;
+ * if it's 0, set it to a default value
+ */
+ io_u->error = nbd_get_errno();
+ if (io_u->error == 0)
+ io_u->error = EIO;
+ return FIO_Q_COMPLETED;
+ }
+
+ if (nbd_data->debug)
+ log_info("fio: nbd: command issued\n");
+ io_u->error = 0;
+ return FIO_Q_QUEUED;
+}
+
+static unsigned retire_commands(struct nbd_handle *nbd)
+{
+ int64_t cookie;
+ unsigned r = 0;
+
+ while ((cookie = nbd_aio_peek_command_completed(nbd)) > 0) {
+ /* Ignore the return value. cmd_completed has already
+ * checked for an error and set io_u->error. We only
+ * have to call this to retire the command.
+ */
+ nbd_aio_command_completed(nbd, cookie);
+ r++;
+ }
+
+ if (nbd_get_debug(nbd))
+ log_info("fio: nbd: %u commands retired\n", r);
+ return r;
+}
+
+static int nbd_getevents(struct thread_data *td, unsigned int min,
+ unsigned int max, const struct timespec *t)
+{
+ struct nbd_data *nbd_data = td->io_ops_data;
+ int r;
+ unsigned events = 0;
+ int timeout;
+
+ /* XXX This handling of timeout is wrong because it will wait
+ * for up to loop iterations * timeout.
+ */
+ timeout = !t ? -1 : t->tv_sec * 1000 + t->tv_nsec / 1000000;
+
+ while (events < min) {
+ r = nbd_poll(nbd_data->nbd, timeout);
+ if (r == -1) {
+ /* error in poll */
+ log_err("fio: nbd_poll: %s\n", nbd_get_error());
+ return -1;
+ }
+ else {
+ /* poll made progress */
+ events += retire_commands(nbd_data->nbd);
+ }
+ }
+
+ return events;
+}
+
+static struct io_u *nbd_event(struct thread_data *td, int event)
+{
+ struct nbd_data *nbd_data = td->io_ops_data;
+
+ if (nbd_data->nr_completed == 0)
+ return NULL;
+
+ /* XXX We ignore the event number and assume fio calls us
+ * exactly once for [0..nr_events-1].
+ */
+ nbd_data->nr_completed--;
+ return nbd_data->completed[nbd_data->nr_completed];
+}
+
+static int nbd_io_u_init(struct thread_data *td, struct io_u *io_u)
+{
+ io_u->engine_data = NULL;
+ return 0;
+}
+
+static void nbd_io_u_free(struct thread_data *td, struct io_u *io_u)
+{
+ /* Nothing needs to be done. */
+}
+
+static int nbd_open_file(struct thread_data *td, struct fio_file *f)
+{
+ return 0;
+}
+
+static int nbd_invalidate(struct thread_data *td, struct fio_file *f)
+{
+ return 0;
+}
+
+static struct ioengine_ops ioengine = {
+ .name = "nbd",
+ .version = FIO_IOOPS_VERSION,
+ .options = options,
+ .option_struct_size = sizeof(struct nbd_options),
+ .flags = FIO_DISKLESSIO | FIO_NOEXTEND,
+
+ .setup = nbd_setup,
+ .init = nbd_init,
+ .cleanup = nbd_cleanup,
+ .queue = nbd_queue,
+ .getevents = nbd_getevents,
+ .event = nbd_event,
+ .io_u_init = nbd_io_u_init,
+ .io_u_free = nbd_io_u_free,
+
+ .open_file = nbd_open_file,
+ .invalidate = nbd_invalidate,
+};
+
+static void fio_init fio_nbd_register(void)
+{
+ register_ioengine(&ioengine);
+}
+
+static void fio_exit fio_nbd_unregister(void)
+{
+ unregister_ioengine(&ioengine);
+}
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