diff --git a/fio-io.c b/fio-io.c
new file mode 100644
index 0000000..3183e8f
--- /dev/null
+++ b/fio-io.c
@@ -0,0 +1,603 @@
+/*
+ * The io parts of the fio tool, includes workers for sync and mmap'ed
+ * io, as well as both posix and linux libaio support.
+ *
+ * sync io is implemented on top of aio.
+ *
+ * This is not really specific to fio, if the get_io_u/put_io_u and
+ * structures was pulled into this as well it would be a perfectly
+ * generic io engine that could be used for other projects.
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
+#include <time.h>
+#include <sys/mman.h>
+#include "fio.h"
+#include "os.h"
+
+#ifdef FIO_HAVE_LIBAIO
+
+#define ev_to_iou(ev)	(struct io_u *) ((unsigned long) (ev)->obj)
+
+static int fio_io_sync(struct thread_data *td)
+{
+	return fsync(td->fd);
+}
+
+static int fill_timespec(struct timespec *ts)
+{
+#ifdef _POSIX_TIMERS
+	if (!clock_gettime(CLOCK_MONOTONIC, ts))
+		return 0;
+
+	perror("clock_gettime");
+#endif
+	return 1;
+}
+
+static unsigned long long ts_utime_since_now(struct timespec *t)
+{
+	long long sec, nsec;
+	struct timespec now;
+
+	if (fill_timespec(&now))
+		return 0;
+	
+	sec = now.tv_sec - t->tv_sec;
+	nsec = now.tv_nsec - t->tv_nsec;
+	if (sec > 0 && nsec < 0) {
+		sec--;
+		nsec += 1000000000;
+	}
+
+	sec *= 1000000;
+	nsec /= 1000;
+	return sec + nsec;
+}
+
+struct libaio_data {
+	io_context_t aio_ctx;
+	struct io_event *aio_events;
+};
+
+static int fio_libaio_io_prep(struct thread_data *td, struct io_u *io_u)
+{
+	if (io_u->ddir == DDIR_READ)
+		io_prep_pread(&io_u->iocb, td->fd, io_u->buf, io_u->buflen, io_u->offset);
+	else
+		io_prep_pwrite(&io_u->iocb, td->fd, io_u->buf, io_u->buflen, io_u->offset);
+
+	return 0;
+}
+
+static struct io_u *fio_libaio_event(struct thread_data *td, int event)
+{
+	struct libaio_data *ld = td->io_data;
+
+	return ev_to_iou(ld->aio_events + event);
+}
+
+static int fio_libaio_getevents(struct thread_data *td, int min, int max,
+				struct timespec *t)
+{
+	struct libaio_data *ld = td->io_data;
+	int r;
+
+	do {
+		r = io_getevents(ld->aio_ctx, min, max, ld->aio_events, t);
+		if (r == -EAGAIN) {
+			usleep(100);
+			continue;
+		} else if (r == -EINTR)
+			continue;
+		else
+			break;
+	} while (1);
+
+	return r;
+}
+
+static int fio_libaio_queue(struct thread_data *td, struct io_u *io_u)
+{
+	struct libaio_data *ld = td->io_data;
+	struct iocb *iocb = &io_u->iocb;
+	int ret;
+
+	do {
+		ret = io_submit(ld->aio_ctx, 1, &iocb);
+		if (ret == 1)
+			return 0;
+		else if (ret == -EAGAIN)
+			usleep(100);
+		else if (ret == -EINTR)
+			continue;
+		else
+			break;
+	} while (1);
+
+	return ret;
+
+}
+
+static int fio_libaio_cancel(struct thread_data *td, struct io_u *io_u)
+{
+	struct libaio_data *ld = td->io_data;
+
+	return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);
+}
+
+static void fio_libaio_cleanup(struct thread_data *td)
+{
+	struct libaio_data *ld = td->io_data;
+
+	if (ld) {
+		io_destroy(ld->aio_ctx);
+		if (ld->aio_events)
+			free(ld->aio_events);
+
+		free(ld);
+		td->io_data = NULL;
+	}
+}
+
+int fio_libaio_init(struct thread_data *td)
+{
+	struct libaio_data *ld = malloc(sizeof(*ld));
+
+	memset(ld, 0, sizeof(*ld));
+	if (io_queue_init(td->iodepth, &ld->aio_ctx)) {
+		td_verror(td, errno);
+		return 1;
+	}
+
+	td->io_prep = fio_libaio_io_prep;
+	td->io_queue = fio_libaio_queue;
+	td->io_getevents = fio_libaio_getevents;
+	td->io_event = fio_libaio_event;
+	td->io_cancel = fio_libaio_cancel;
+	td->io_cleanup = fio_libaio_cleanup;
+	td->io_sync = fio_io_sync;
+
+	ld->aio_events = malloc(td->iodepth * sizeof(struct io_event));
+	td->io_data = ld;
+	return 0;
+}
+
+#else /* FIO_HAVE_LIBAIO */
+
+int fio_libaio_init(struct thread_data *td)
+{
+	return EINVAL;
+}
+
+#endif /* FIO_HAVE_LIBAIO */
+
+#ifdef FIO_HAVE_POSIXAIO
+
+struct posixaio_data {
+	struct io_u **aio_events;
+};
+
+static int fio_posixaio_cancel(struct thread_data *td, struct io_u *io_u)
+{
+	int r = aio_cancel(td->fd, &io_u->aiocb);
+
+	if (r == 1 || r == AIO_CANCELED)
+		return 0;
+
+	return 1;
+}
+
+static int fio_posixaio_prep(struct thread_data *td, struct io_u *io_u)
+{
+	struct aiocb *aiocb = &io_u->aiocb;
+
+	aiocb->aio_fildes = td->fd;
+	aiocb->aio_buf = io_u->buf;
+	aiocb->aio_nbytes = io_u->buflen;
+	aiocb->aio_offset = io_u->offset;
+
+	io_u->seen = 0;
+	return 0;
+}
+
+static int fio_posixaio_getevents(struct thread_data *td, int min, int max,
+				  struct timespec *t)
+{
+	struct posixaio_data *pd = td->io_data;
+	struct list_head *entry;
+	struct timespec start;
+	int r, have_timeout = 0;
+
+	if (t && !fill_timespec(&start))
+		have_timeout = 1;
+
+	r = 0;
+restart:
+	list_for_each(entry, &td->io_u_busylist) {
+		struct io_u *io_u = list_entry(entry, struct io_u, list);
+		int err;
+
+		if (io_u->seen)
+			continue;
+
+		err = aio_error(&io_u->aiocb);
+		switch (err) {
+			default:
+				io_u->error = err;
+			case ECANCELED:
+			case 0:
+				pd->aio_events[r++] = io_u;
+				io_u->seen = 1;
+				break;
+			case EINPROGRESS:
+				break;
+		}
+
+		if (r >= max)
+			break;
+	}
+
+	if (r >= min)
+		return r;
+
+	if (have_timeout) {
+		unsigned long long usec;
+
+		usec = (t->tv_sec * 1000000) + (t->tv_nsec / 1000);
+		if (ts_utime_since_now(&start) > usec)
+			return r;
+	}
+
+	/*
+	 * hrmpf, we need to wait for more. we should use aio_suspend, for
+	 * now just sleep a little and recheck status of busy-and-not-seen
+	 */
+	usleep(1000);
+	goto restart;
+}
+
+static struct io_u *fio_posixaio_event(struct thread_data *td, int event)
+{
+	struct posixaio_data *pd = td->io_data;
+
+	return pd->aio_events[event];
+}
+
+static int fio_posixaio_queue(struct thread_data *td, struct io_u *io_u)
+{
+	struct aiocb *aiocb = &io_u->aiocb;
+	int ret;
+
+	if (io_u->ddir == DDIR_READ)
+		ret = aio_read(aiocb);
+	else
+		ret = aio_write(aiocb);
+
+	if (ret)
+		io_u->error = errno;
+		
+	return io_u->error;
+}
+
+static void fio_posixaio_cleanup(struct thread_data *td)
+{
+	struct posixaio_data *pd = td->io_data;
+
+	if (pd) {
+		free(pd->aio_events);
+		free(pd);
+		td->io_data = NULL;
+	}
+}
+
+int fio_posixaio_init(struct thread_data *td)
+{
+	struct posixaio_data *pd = malloc(sizeof(*pd));
+
+	pd->aio_events = malloc(td->iodepth * sizeof(struct io_u *));
+
+	td->io_prep = fio_posixaio_prep;
+	td->io_queue = fio_posixaio_queue;
+	td->io_getevents = fio_posixaio_getevents;
+	td->io_event = fio_posixaio_event;
+	td->io_cancel = fio_posixaio_cancel;
+	td->io_cleanup = fio_posixaio_cleanup;
+	td->io_sync = fio_io_sync;
+
+	td->io_data = pd;
+	return 0;
+}
+
+#else /* FIO_HAVE_POSIXAIO */
+
+int fio_posixaio_init(struct thread_data *td)
+{
+	return EINVAL;
+}
+
+#endif /* FIO_HAVE_POSIXAIO */
+
+struct syncio_data {
+	struct io_u *last_io_u;
+};
+
+static int fio_syncio_getevents(struct thread_data *td, int min, int max,
+				struct timespec *t)
+{
+	assert(max <= 1);
+
+	/*
+	 * we can only have one finished io_u for sync io, since the depth
+	 * is always 1
+	 */
+	if (list_empty(&td->io_u_busylist))
+		return 0;
+
+	return 1;
+}
+
+static struct io_u *fio_syncio_event(struct thread_data *td, int event)
+{
+	struct syncio_data *sd = td->io_data;
+
+	assert(event == 0);
+
+	return sd->last_io_u;
+}
+
+static int fio_syncio_prep(struct thread_data *td, struct io_u *io_u)
+{
+	if (td->cur_off != io_u->offset) {
+		if (lseek(td->fd, io_u->offset, SEEK_SET) == -1) {
+			td_verror(td, errno);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+static int fio_syncio_queue(struct thread_data *td, struct io_u *io_u)
+{
+	struct syncio_data *sd = td->io_data;
+	int ret;
+
+	if (io_u->ddir == DDIR_READ)
+		ret = read(td->fd, io_u->buf, io_u->buflen);
+	else
+		ret = write(td->fd, io_u->buf, io_u->buflen);
+
+	if ((unsigned int) ret != io_u->buflen) {
+		if (ret > 0) {
+			io_u->resid = io_u->buflen - ret;
+			io_u->error = ENODATA;
+		} else
+			io_u->error = errno;
+	}
+
+	if (!io_u->error)
+		sd->last_io_u = io_u;
+
+	return io_u->error;
+}
+
+static void fio_syncio_cleanup(struct thread_data *td)
+{
+	if (td->io_data) {
+		free(td->io_data);
+		td->io_data = NULL;
+	}
+}
+
+int fio_syncio_init(struct thread_data *td)
+{
+	struct syncio_data *sd = malloc(sizeof(*sd));
+
+	td->io_prep = fio_syncio_prep;
+	td->io_queue = fio_syncio_queue;
+	td->io_getevents = fio_syncio_getevents;
+	td->io_event = fio_syncio_event;
+	td->io_cancel = NULL;
+	td->io_cleanup = fio_syncio_cleanup;
+	td->io_sync = fio_io_sync;
+
+	sd->last_io_u = NULL;
+	td->io_data = sd;
+	return 0;
+}
+
+static int fio_mmapio_queue(struct thread_data *td, struct io_u *io_u)
+{
+	unsigned long long real_off = io_u->offset - td->file_offset;
+	struct syncio_data *sd = td->io_data;
+
+	if (io_u->ddir == DDIR_READ)
+		memcpy(io_u->buf, td->mmap + real_off, io_u->buflen);
+	else
+		memcpy(td->mmap + real_off, io_u->buf, io_u->buflen);
+
+	/*
+	 * not really direct, but should drop the pages from the cache
+	 */
+	if (td->odirect) {
+		if (msync(td->mmap + real_off, io_u->buflen, MS_SYNC) < 0)
+			io_u->error = errno;
+		if (madvise(td->mmap + real_off, io_u->buflen,  MADV_DONTNEED) < 0)
+			io_u->error = errno;
+	}
+
+	if (!io_u->error)
+		sd->last_io_u = io_u;
+
+	return io_u->error;
+}
+
+static int fio_mmapio_sync(struct thread_data *td)
+{
+	return msync(td->mmap, td->file_size, MS_SYNC);
+}
+
+int fio_mmapio_init(struct thread_data *td)
+{
+	struct syncio_data *sd = malloc(sizeof(*sd));
+
+	td->io_prep = NULL;
+	td->io_queue = fio_mmapio_queue;
+	td->io_getevents = fio_syncio_getevents;
+	td->io_event = fio_syncio_event;
+	td->io_cancel = NULL;
+	td->io_cleanup = fio_syncio_cleanup;
+	td->io_sync = fio_mmapio_sync;
+
+	sd->last_io_u = NULL;
+	td->io_data = sd;
+	return 0;
+}
+
+#ifdef FIO_HAVE_SGIO
+
+struct sgio_data {
+	struct io_u *last_io_u;
+	unsigned char cdb[10];
+	unsigned int bs;
+};
+
+static inline void sgio_hdr_init(struct sgio_data *sd, struct sg_io_hdr *hdr,
+				 struct io_u *io_u)
+{
+	memset(hdr, 0, sizeof(*hdr));
+	memset(sd->cdb, 0, sizeof(sd->cdb));
+
+	hdr->interface_id = 'S';
+	hdr->cmdp = sd->cdb;
+	hdr->cmd_len = sizeof(sd->cdb);
+
+	if (io_u) {
+		hdr->dxferp = io_u->buf;
+		hdr->dxfer_len = io_u->buflen;
+	}
+}
+
+static int fio_sgio_sync(struct thread_data *td)
+{
+	struct sgio_data *sd = td->io_data;
+	struct sg_io_hdr hdr;
+
+	sgio_hdr_init(sd, &hdr, NULL);
+	hdr.dxfer_direction = SG_DXFER_NONE;
+
+	hdr.cmdp[0] = 0x35;
+
+	return ioctl(td->fd, SG_IO, &hdr);
+}
+
+static int fio_sgio_prep(struct thread_data *td, struct io_u *io_u)
+{
+	struct sg_io_hdr *hdr = &io_u->hdr;
+	struct sgio_data *sd = td->io_data;
+	int nr_blocks, lba;
+
+	if (io_u->buflen & (sd->bs - 1)) {
+		fprintf(stderr, "read/write not sector aligned\n");
+		return EINVAL;
+	}
+
+	sgio_hdr_init(sd, hdr, io_u);
+
+	if (io_u->ddir == DDIR_READ) {
+		hdr->dxfer_direction = SG_DXFER_FROM_DEV;
+		hdr->cmdp[0] = 0x28;
+	} else {
+		hdr->dxfer_direction = SG_DXFER_TO_DEV;
+		hdr->cmdp[0] = 0x2a;
+	}
+
+	nr_blocks = io_u->buflen / sd->bs;
+	lba = io_u->offset / sd->bs;
+	hdr->cmdp[2] = (lba >> 24) & 0xff;
+	hdr->cmdp[3] = (lba >> 16) & 0xff;
+	hdr->cmdp[4] = (lba >>  8) & 0xff;
+	hdr->cmdp[5] = lba & 0xff;
+	hdr->cmdp[7] = (nr_blocks >> 8) & 0xff;
+	hdr->cmdp[8] = nr_blocks & 0xff;
+	return 0;
+}
+
+static int fio_sgio_queue(struct thread_data *td, struct io_u *io_u)
+{
+	struct sg_io_hdr *hdr = &io_u->hdr;
+	struct sgio_data *sd = td->io_data;
+	int ret;
+
+	ret = ioctl(td->fd, SG_IO, hdr);
+	if (ret < 0)
+		io_u->error = errno;
+	else if (hdr->status) {
+		io_u->resid = hdr->resid;
+		io_u->error = EIO;
+	}
+
+	if (!io_u->error)
+		sd->last_io_u = io_u;
+
+	return io_u->error;
+}
+
+static struct io_u *fio_sgio_event(struct thread_data *td, int event)
+{
+	struct sgio_data *sd = td->io_data;
+
+	assert(event == 0);
+
+	return sd->last_io_u;
+}
+
+int fio_sgio_init(struct thread_data *td)
+{
+	struct sgio_data *sd;
+	int bs;
+
+	if (td->filetype != FIO_TYPE_BD) {
+		fprintf(stderr, "ioengine sgio only works on block devices\n");
+		return 1;
+	}
+
+	if (ioctl(td->fd, BLKSSZGET, &bs) < 0) {
+		td_verror(td, errno);
+		return 1;
+	}
+
+	sd = malloc(sizeof(*sd));
+	sd->bs = bs;
+
+	td->io_prep = fio_sgio_prep;
+	td->io_queue = fio_sgio_queue;
+	td->io_getevents = fio_syncio_getevents;
+	td->io_event = fio_sgio_event;
+	td->io_cancel = NULL;
+	td->io_cleanup = fio_syncio_cleanup;
+	td->io_sync = fio_sgio_sync;
+
+	/*
+	 * we want to do it, regardless of whether odirect is set or not
+	 */
+	td->override_sync = 1;
+
+	sd->last_io_u = NULL;
+	td->io_data = sd;
+	return 0;
+}
+
+#else /* FIO_HAVE_SGIO */
+
+int fio_sgio_init(struct thread_data *td)
+{
+	return EINVAL;
+}
+
+#endif /* FIO_HAVE_SGIO */