ioengines.c - fp2-dev/platform/external/fio - Gitiles

 /*
  * 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 <string.h>
 #include <dlfcn.h>
 #include <fcntl.h>
 #include <assert.h>

 #include "fio.h"
 #include "diskutil.h"

 static FLIST_HEAD(engine_list);

 static int check_engine_ops(struct ioengine_ops *ops)
 {
 	if (ops->version != FIO_IOOPS_VERSION) {
 		log_err("bad ioops version %d (want %d)\n", ops->version,
 							FIO_IOOPS_VERSION);
 		return 1;
 	}

 	if (!ops->queue) {
 		log_err("%s: no queue handler\n", ops->name);
 		return 1;
 	}

 	/*
 	 * sync engines only need a ->queue()
 	 */
 	if (ops->flags & FIO_SYNCIO)
 		return 0;

 	if (!ops->event) {
 		log_err("%s: no event handler\n", ops->name);
 		return 1;
 	}
 	if (!ops->getevents) {
 		log_err("%s: no getevents handler\n", ops->name);
 		return 1;
 	}
 	if (!ops->queue) {
 		log_err("%s: no queue handler\n", ops->name);
 		return 1;
 	}

 	return 0;
 }

 void unregister_ioengine(struct ioengine_ops *ops)
 {
 	dprint(FD_IO, "ioengine %s unregistered\n", ops->name);
 	flist_del(&ops->list);
 	INIT_FLIST_HEAD(&ops->list);
 }

 void register_ioengine(struct ioengine_ops *ops)
 {
 	dprint(FD_IO, "ioengine %s registered\n", ops->name);
 	INIT_FLIST_HEAD(&ops->list);
 	flist_add_tail(&ops->list, &engine_list);
 }

 static struct ioengine_ops *find_ioengine(const char *name)
 {
 	struct ioengine_ops *ops;
 	struct flist_head *entry;

 	flist_for_each(entry, &engine_list) {
 		ops = flist_entry(entry, struct ioengine_ops, list);
 		if (!strcmp(name, ops->name))
 			return ops;
 	}

 	return NULL;
 }

 static struct ioengine_ops *dlopen_ioengine(struct thread_data *td,
 					    const char *engine_lib)
 {
 	struct ioengine_ops *ops;
 	void *dlhandle;

 	dprint(FD_IO, "dload engine %s\n", engine_lib);

 	dlerror();
 	dlhandle = dlopen(engine_lib, RTLD_LAZY);
 	if (!dlhandle) {
 		td_vmsg(td, -1, dlerror(), "dlopen");
 		return NULL;
 	}

 	/*
 	 * Unlike the included modules, external engines should have a
 	 * non-static ioengine structure that we can reference.
 	 */
 	ops = dlsym(dlhandle, "ioengine");
 	if (!ops) {
 		td_vmsg(td, -1, dlerror(), "dlsym");
 		dlclose(dlhandle);
 		return NULL;
 	}

 	ops->dlhandle = dlhandle;
 	return ops;
 }

 struct ioengine_ops *load_ioengine(struct thread_data *td, const char *name)
 {
 	struct ioengine_ops *ops, *ret;
 	char engine[16];

 	dprint(FD_IO, "load ioengine %s\n", name);

 	strncpy(engine, name, sizeof(engine) - 1);

 	/*
 	 * linux libaio has alias names, so convert to what we want
 	 */
 	if (!strncmp(engine, "linuxaio", 8) || !strncmp(engine, "aio", 3))
 		strcpy(engine, "libaio");

 	ops = find_ioengine(engine);
 	if (!ops)
 		ops = dlopen_ioengine(td, name);

 	if (!ops) {
 		log_err("fio: engine %s not loadable\n", name);
 		return NULL;
 	}

 	/*
 	 * Check that the required methods are there.
 	 */
 	if (check_engine_ops(ops))
 		return NULL;

 	ret = malloc(sizeof(*ret));
 	memcpy(ret, ops, sizeof(*ret));
 	ret->data = NULL;

 	return ret;
 }

 /*
  * For cleaning up an ioengine which never made it to init().
  */
 void free_ioengine(struct thread_data *td)
 {
 	dprint(FD_IO, "free ioengine %s\n", td->io_ops->name);

 	if (td->eo && td->io_ops->options) {
 		options_free(td->io_ops->options, td->eo);
 		free(td->eo);
 		td->eo = NULL;
 	}

 	if (td->io_ops->dlhandle)
 		dlclose(td->io_ops->dlhandle);

 	free(td->io_ops);
 	td->io_ops = NULL;
 }

 void close_ioengine(struct thread_data *td)
 {
 	dprint(FD_IO, "close ioengine %s\n", td->io_ops->name);

 	if (td->io_ops->cleanup) {
 		td->io_ops->cleanup(td);
 		td->io_ops->data = NULL;
 	}

 	free_ioengine(td);
 }

 int td_io_prep(struct thread_data *td, struct io_u *io_u)
 {
 	dprint_io_u(io_u, "prep");
 	fio_ro_check(td, io_u);

 	lock_file(td, io_u->file, io_u->ddir);

 	if (td->io_ops->prep) {
 		int ret = td->io_ops->prep(td, io_u);

 		dprint(FD_IO, "->prep(%p)=%d\n", io_u, ret);
 		if (ret)
 			unlock_file(td, io_u->file);
 		return ret;
 	}

 	return 0;
 }

 int td_io_getevents(struct thread_data *td, unsigned int min, unsigned int max,
 		    struct timespec *t)
 {
 	int r = 0;

 	if (min > 0 && td->io_ops->commit) {
 		r = td->io_ops->commit(td);
 		if (r < 0)
 			goto out;
 	}
 	if (max > td->cur_depth)
 		max = td->cur_depth;
 	if (min > max)
 		max = min;

 	r = 0;
 	if (max && td->io_ops->getevents)
 		r = td->io_ops->getevents(td, min, max, t);
 out:
 	if (r >= 0) {
 		/*
  		 * Reflect that our submitted requests were retrieved with
 		 * whatever OS async calls are in the underlying engine.
 		 */
 		td->io_u_in_flight -= r;
 		io_u_mark_complete(td, r);
 	} else
 		td_verror(td, r, "get_events");

 	dprint(FD_IO, "getevents: %d\n", r);
 	return r;
 }

 int td_io_queue(struct thread_data *td, struct io_u *io_u)
 {
 	int ret;

 	dprint_io_u(io_u, "queue");
 	fio_ro_check(td, io_u);

 	assert((io_u->flags & IO_U_F_FLIGHT) == 0);
 	io_u->flags |= IO_U_F_FLIGHT;

 	assert(fio_file_open(io_u->file));

 	io_u->error = 0;
 	io_u->resid = 0;

 	if (td->io_ops->flags & FIO_SYNCIO) {
 		if (fio_fill_issue_time(td))
 			fio_gettime(&io_u->issue_time, NULL);

 		/*
 		 * only used for iolog
 		 */
 		if (td->o.read_iolog_file)
 			memcpy(&td->last_issue, &io_u->issue_time,
 					sizeof(struct timeval));
 	}

 	if (ddir_rw(io_u->ddir))
 		td->io_issues[io_u->ddir]++;

 	ret = td->io_ops->queue(td, io_u);

 	unlock_file(td, io_u->file);

 	/*
 	 * Add warning for O_DIRECT so that users have an easier time
 	 * spotting potentially bad alignment. If this triggers for the first
 	 * IO, then it's likely an alignment problem or because the host fs
 	 * does not support O_DIRECT
 	 */
 	if (io_u->error == EINVAL && td->io_issues[io_u->ddir & 1] == 1 &&
 	    td->o.odirect) {
 		log_info("fio: first direct IO errored. File system may not "
 			 "support direct IO, or iomem_align= is bad.\n");
 	}

 	if (!td->io_ops->commit) {
 		io_u_mark_submit(td, 1);
 		io_u_mark_complete(td, 1);
 	}

 	if (ret == FIO_Q_COMPLETED) {
 		if (ddir_rw(io_u->ddir)) {
 			io_u_mark_depth(td, 1);
 			td->ts.total_io_u[io_u->ddir]++;
 		} else if (io_u->ddir == DDIR_TRIM)
 			td->ts.total_io_u[2]++;
 	} else if (ret == FIO_Q_QUEUED) {
 		int r;

 		if (ddir_rw(io_u->ddir)) {
 			td->io_u_queued++;
 			td->ts.total_io_u[io_u->ddir]++;
 		}

 		if (td->io_u_queued >= td->o.iodepth_batch) {
 			r = td_io_commit(td);
 			if (r < 0)
 				return r;
 		}
 	}

 	if ((td->io_ops->flags & FIO_SYNCIO) == 0) {
 		if (fio_fill_issue_time(td))
 			fio_gettime(&io_u->issue_time, NULL);

 		/*
 		 * only used for iolog
 		 */
 		if (td->o.read_iolog_file)
 			memcpy(&td->last_issue, &io_u->issue_time,
 					sizeof(struct timeval));
 	}

 	return ret;
 }

 int td_io_init(struct thread_data *td)
 {
 	int ret = 0;

 	if (td->io_ops->init) {
 		ret = td->io_ops->init(td);
 		if (ret && td->o.iodepth > 1) {
 			log_err("fio: io engine init failed. Perhaps try"
 				" reducing io depth?\n");
 		}
 		if (!td->error)
 			td->error = ret;
 	}

 	return ret;
 }

 int td_io_commit(struct thread_data *td)
 {
 	int ret;

 	dprint(FD_IO, "calling ->commit(), depth %d\n", td->cur_depth);

 	if (!td->cur_depth || !td->io_u_queued)
 		return 0;

 	io_u_mark_depth(td, td->io_u_queued);

 	if (td->io_ops->commit) {
 		ret = td->io_ops->commit(td);
 		if (ret)
 			td_verror(td, -ret, "io commit");
 	}

 	/*
 	 * Reflect that events were submitted as async IO requests.
 	 */
 	td->io_u_in_flight += td->io_u_queued;
 	td->io_u_queued = 0;

 	return 0;
 }

 int td_io_open_file(struct thread_data *td, struct fio_file *f)
 {
 	assert(!fio_file_open(f));
 	assert(f->fd == -1);

 	if (td->io_ops->open_file(td, f)) {
 		if (td->error == EINVAL && td->o.odirect)
 			log_err("fio: destination does not support O_DIRECT\n");
 		if (td->error == EMFILE) {
 			log_err("fio: try reducing/setting openfiles (failed"
 				" at %u of %u)\n", td->nr_open_files,
 							td->o.nr_files);
 		}

 		assert(f->fd == -1);
 		assert(!fio_file_open(f));
 		return 1;
 	}

 	fio_file_reset(f);
 	fio_file_set_open(f);
 	fio_file_clear_closing(f);
 	disk_util_inc(f->du);

 	td->nr_open_files++;
 	get_file(f);

 	if (f->filetype == FIO_TYPE_PIPE) {
 		if (td_random(td)) {
 			log_err("fio: can't seek on pipes (no random io)\n");
 			goto err;
 		}
 	}

 	if (td->io_ops->flags & FIO_DISKLESSIO)
 		goto done;

 	if (td->o.invalidate_cache && file_invalidate_cache(td, f))
 		goto err;

 	if (td->o.fadvise_hint &&
 	    (f->filetype == FIO_TYPE_BD || f->filetype == FIO_TYPE_FILE)) {
 		int flags;

 		if (td_random(td))
 			flags = POSIX_FADV_RANDOM;
 		else
 			flags = POSIX_FADV_SEQUENTIAL;

 		if (posix_fadvise(f->fd, f->file_offset, f->io_size, flags) < 0) {
 			td_verror(td, errno, "fadvise");
 			goto err;
 		}
 	}

 #ifdef FIO_OS_DIRECTIO
 	/*
 	 * Some OS's have a distinct call to mark the file non-buffered,
 	 * instead of using O_DIRECT (Solaris)
 	 */
 	if (td->o.odirect) {
 		int ret = fio_set_odirect(f->fd);

 		if (ret) {
 			td_verror(td, ret, "fio_set_odirect");
 			log_err("fio: the file system does not seem to support direct IO\n");
 			goto err;
 		}
 	}
 #endif

 done:
 	log_file(td, f, FIO_LOG_OPEN_FILE);
 	return 0;
 err:
 	disk_util_dec(f->du);
 	if (td->io_ops->close_file)
 		td->io_ops->close_file(td, f);
 	return 1;
 }

 int td_io_close_file(struct thread_data *td, struct fio_file *f)
 {
 	if (!fio_file_closing(f))
 		log_file(td, f, FIO_LOG_CLOSE_FILE);

 	/*
 	 * mark as closing, do real close when last io on it has completed
 	 */
 	fio_file_set_closing(f);

 	disk_util_dec(f->du);
 	unlock_file_all(td, f);

 	return put_file(td, f);
 }

 int td_io_get_file_size(struct thread_data *td, struct fio_file *f)
 {
 	if (!td->io_ops->get_file_size)
 		return 0;

 	return td->io_ops->get_file_size(td, f);
 }

 static int do_sync_file_range(struct thread_data *td, struct fio_file *f)
 {
 	off64_t offset, nbytes;

 	offset = f->first_write;
 	nbytes = f->last_write - f->first_write;

 	if (!nbytes)
 		return 0;

 	return sync_file_range(f->fd, offset, nbytes, td->o.sync_file_range);
 }

 int do_io_u_sync(struct thread_data *td, struct io_u *io_u)
 {
 	int ret;

 	if (io_u->ddir == DDIR_SYNC) {
 		ret = fsync(io_u->file->fd);
 	} else if (io_u->ddir == DDIR_DATASYNC) {
 #ifdef FIO_HAVE_FDATASYNC
 		ret = fdatasync(io_u->file->fd);
 #else
 		ret = io_u->xfer_buflen;
 		io_u->error = EINVAL;
 #endif
 	} else if (io_u->ddir == DDIR_SYNC_FILE_RANGE)
 		ret = do_sync_file_range(td, io_u->file);
 	else {
 		ret = io_u->xfer_buflen;
 		io_u->error = EINVAL;
 	}

 	if (ret < 0)
 		io_u->error = errno;

 	return ret;
 }

 int do_io_u_trim(struct thread_data *td, struct io_u *io_u)
 {
 #ifndef FIO_HAVE_TRIM
 	io_u->error = EINVAL;
 	return 0;
 #else
 	struct fio_file *f = io_u->file;
 	int ret;

 	ret = os_trim(f->fd, io_u->offset, io_u->xfer_buflen);
 	if (!ret)
 		return io_u->xfer_buflen;;

 	io_u->error = ret;
 	return 0;
 #endif
 }

 int fio_show_ioengine_help(const char *engine)
 {
 	struct flist_head *entry;
 	struct thread_data td;
 	char *sep;
 	int ret = 1;

 	if (!engine || !*engine) {
 		log_info("Available IO engines:\n");
 		flist_for_each(entry, &engine_list) {
 			td.io_ops = flist_entry(entry, struct ioengine_ops,
 						list);
 			log_info("\t%s\n", td.io_ops->name);
 		}
 		return 0;
 	}
 	sep = strchr(engine, ',');
 	if (sep) {
 		*sep = 0;
 		sep++;
 	}

 	memset(&td, 0, sizeof(td));

 	td.io_ops = load_ioengine(&td, engine);
 	if (!td.io_ops) {
 		log_info("IO engine %s not found\n", engine);
 		return 1;
 	}

 	if (td.io_ops->options)
 		ret = show_cmd_help(td.io_ops->options, sep);
 	else
 		log_info("IO engine %s has no options\n", td.io_ops->name);

 	free_ioengine(&td);

 	return ret;
 }
	/*
	* 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 <string.h>
	#include <dlfcn.h>
	#include <fcntl.h>
	#include <assert.h>

	#include "fio.h"
	#include "diskutil.h"

	static FLIST_HEAD(engine_list);

	static int check_engine_ops(struct ioengine_ops *ops)
	{
	if (ops->version != FIO_IOOPS_VERSION) {
	log_err("bad ioops version %d (want %d)\n", ops->version,
	FIO_IOOPS_VERSION);
	return 1;
	}

	if (!ops->queue) {
	log_err("%s: no queue handler\n", ops->name);
	return 1;
	}

	/*
	* sync engines only need a ->queue()
	*/
	if (ops->flags & FIO_SYNCIO)
	return 0;

	if (!ops->event) {
	log_err("%s: no event handler\n", ops->name);
	return 1;
	}
	if (!ops->getevents) {
	log_err("%s: no getevents handler\n", ops->name);
	return 1;
	}
	if (!ops->queue) {
	log_err("%s: no queue handler\n", ops->name);
	return 1;
	}

	return 0;
	}

	void unregister_ioengine(struct ioengine_ops *ops)
	{
	dprint(FD_IO, "ioengine %s unregistered\n", ops->name);
	flist_del(&ops->list);
	INIT_FLIST_HEAD(&ops->list);
	}

	void register_ioengine(struct ioengine_ops *ops)
	{
	dprint(FD_IO, "ioengine %s registered\n", ops->name);
	INIT_FLIST_HEAD(&ops->list);
	flist_add_tail(&ops->list, &engine_list);
	}

	static struct ioengine_ops find_ioengine(const char name)
	{
	struct ioengine_ops *ops;
	struct flist_head *entry;

	flist_for_each(entry, &engine_list) {
	ops = flist_entry(entry, struct ioengine_ops, list);
	if (!strcmp(name, ops->name))
	return ops;
	}

	return NULL;
	}

	static struct ioengine_ops dlopen_ioengine(struct thread_data td,
	const char *engine_lib)
	{
	struct ioengine_ops *ops;
	void *dlhandle;

	dprint(FD_IO, "dload engine %s\n", engine_lib);

	dlerror();
	dlhandle = dlopen(engine_lib, RTLD_LAZY);
	if (!dlhandle) {
	td_vmsg(td, -1, dlerror(), "dlopen");
	return NULL;
	}

	/*
	* Unlike the included modules, external engines should have a
	* non-static ioengine structure that we can reference.
	*/
	ops = dlsym(dlhandle, "ioengine");
	if (!ops) {
	td_vmsg(td, -1, dlerror(), "dlsym");
	dlclose(dlhandle);
	return NULL;
	}

	ops->dlhandle = dlhandle;
	return ops;
	}

	struct ioengine_ops load_ioengine(struct thread_data td, const char *name)
	{
	struct ioengine_ops ops, ret;
	char engine[16];

	dprint(FD_IO, "load ioengine %s\n", name);

	strncpy(engine, name, sizeof(engine) - 1);

	/*
	* linux libaio has alias names, so convert to what we want
	*/
	if (!strncmp(engine, "linuxaio", 8) \|\| !strncmp(engine, "aio", 3))
	strcpy(engine, "libaio");

	ops = find_ioengine(engine);
	if (!ops)
	ops = dlopen_ioengine(td, name);

	if (!ops) {
	log_err("fio: engine %s not loadable\n", name);
	return NULL;
	}

	/*
	* Check that the required methods are there.
	*/
	if (check_engine_ops(ops))
	return NULL;

	ret = malloc(sizeof(*ret));
	memcpy(ret, ops, sizeof(*ret));
	ret->data = NULL;

	return ret;
	}

	/*
	* For cleaning up an ioengine which never made it to init().
	*/
	void free_ioengine(struct thread_data *td)
	{
	dprint(FD_IO, "free ioengine %s\n", td->io_ops->name);

	if (td->eo && td->io_ops->options) {
	options_free(td->io_ops->options, td->eo);
	free(td->eo);
	td->eo = NULL;
	}

	if (td->io_ops->dlhandle)
	dlclose(td->io_ops->dlhandle);

	free(td->io_ops);
	td->io_ops = NULL;
	}

	void close_ioengine(struct thread_data *td)
	{
	dprint(FD_IO, "close ioengine %s\n", td->io_ops->name);

	if (td->io_ops->cleanup) {
	td->io_ops->cleanup(td);
	td->io_ops->data = NULL;
	}

	free_ioengine(td);
	}

	int td_io_prep(struct thread_data td, struct io_u io_u)
	{
	dprint_io_u(io_u, "prep");
	fio_ro_check(td, io_u);

	lock_file(td, io_u->file, io_u->ddir);

	if (td->io_ops->prep) {
	int ret = td->io_ops->prep(td, io_u);

	dprint(FD_IO, "->prep(%p)=%d\n", io_u, ret);
	if (ret)
	unlock_file(td, io_u->file);
	return ret;
	}

	return 0;
	}

	int td_io_getevents(struct thread_data *td, unsigned int min, unsigned int max,
	struct timespec *t)
	{
	int r = 0;

	if (min > 0 && td->io_ops->commit) {
	r = td->io_ops->commit(td);
	if (r < 0)
	goto out;
	}
	if (max > td->cur_depth)
	max = td->cur_depth;
	if (min > max)
	max = min;

	r = 0;
	if (max && td->io_ops->getevents)
	r = td->io_ops->getevents(td, min, max, t);
	out:
	if (r >= 0) {
	/*
	* Reflect that our submitted requests were retrieved with
	* whatever OS async calls are in the underlying engine.
	*/
	td->io_u_in_flight -= r;
	io_u_mark_complete(td, r);
	} else
	td_verror(td, r, "get_events");

	dprint(FD_IO, "getevents: %d\n", r);
	return r;
	}

	int td_io_queue(struct thread_data td, struct io_u io_u)
	{
	int ret;

	dprint_io_u(io_u, "queue");
	fio_ro_check(td, io_u);

	assert((io_u->flags & IO_U_F_FLIGHT) == 0);
	io_u->flags \|= IO_U_F_FLIGHT;

	assert(fio_file_open(io_u->file));

	io_u->error = 0;
	io_u->resid = 0;

	if (td->io_ops->flags & FIO_SYNCIO) {
	if (fio_fill_issue_time(td))
	fio_gettime(&io_u->issue_time, NULL);

	/*
	* only used for iolog
	*/
	if (td->o.read_iolog_file)
	memcpy(&td->last_issue, &io_u->issue_time,
	sizeof(struct timeval));
	}

	if (ddir_rw(io_u->ddir))
	td->io_issues[io_u->ddir]++;

	ret = td->io_ops->queue(td, io_u);

	unlock_file(td, io_u->file);

	/*
	* Add warning for O_DIRECT so that users have an easier time
	* spotting potentially bad alignment. If this triggers for the first
	* IO, then it's likely an alignment problem or because the host fs
	* does not support O_DIRECT
	*/
	if (io_u->error == EINVAL && td->io_issues[io_u->ddir & 1] == 1 &&
	td->o.odirect) {
	log_info("fio: first direct IO errored. File system may not "
	"support direct IO, or iomem_align= is bad.\n");
	}

	if (!td->io_ops->commit) {
	io_u_mark_submit(td, 1);
	io_u_mark_complete(td, 1);
	}

	if (ret == FIO_Q_COMPLETED) {
	if (ddir_rw(io_u->ddir)) {
	io_u_mark_depth(td, 1);
	td->ts.total_io_u[io_u->ddir]++;
	} else if (io_u->ddir == DDIR_TRIM)
	td->ts.total_io_u[2]++;
	} else if (ret == FIO_Q_QUEUED) {
	int r;

	if (ddir_rw(io_u->ddir)) {
	td->io_u_queued++;
	td->ts.total_io_u[io_u->ddir]++;
	}

	if (td->io_u_queued >= td->o.iodepth_batch) {
	r = td_io_commit(td);
	if (r < 0)
	return r;
	}
	}

	if ((td->io_ops->flags & FIO_SYNCIO) == 0) {
	if (fio_fill_issue_time(td))
	fio_gettime(&io_u->issue_time, NULL);

	/*
	* only used for iolog
	*/
	if (td->o.read_iolog_file)
	memcpy(&td->last_issue, &io_u->issue_time,
	sizeof(struct timeval));
	}

	return ret;
	}

	int td_io_init(struct thread_data *td)
	{
	int ret = 0;

	if (td->io_ops->init) {
	ret = td->io_ops->init(td);
	if (ret && td->o.iodepth > 1) {
	log_err("fio: io engine init failed. Perhaps try"
	" reducing io depth?\n");
	}
	if (!td->error)
	td->error = ret;
	}

	return ret;
	}

	int td_io_commit(struct thread_data *td)
	{
	int ret;

	dprint(FD_IO, "calling ->commit(), depth %d\n", td->cur_depth);

	if (!td->cur_depth \|\| !td->io_u_queued)
	return 0;

	io_u_mark_depth(td, td->io_u_queued);

	if (td->io_ops->commit) {
	ret = td->io_ops->commit(td);
	if (ret)
	td_verror(td, -ret, "io commit");
	}

	/*
	* Reflect that events were submitted as async IO requests.
	*/
	td->io_u_in_flight += td->io_u_queued;
	td->io_u_queued = 0;

	return 0;
	}

	int td_io_open_file(struct thread_data td, struct fio_file f)
	{
	assert(!fio_file_open(f));
	assert(f->fd == -1);

	if (td->io_ops->open_file(td, f)) {
	if (td->error == EINVAL && td->o.odirect)
	log_err("fio: destination does not support O_DIRECT\n");
	if (td->error == EMFILE) {
	log_err("fio: try reducing/setting openfiles (failed"
	" at %u of %u)\n", td->nr_open_files,
	td->o.nr_files);
	}

	assert(f->fd == -1);
	assert(!fio_file_open(f));
	return 1;
	}

	fio_file_reset(f);
	fio_file_set_open(f);
	fio_file_clear_closing(f);
	disk_util_inc(f->du);

	td->nr_open_files++;
	get_file(f);

	if (f->filetype == FIO_TYPE_PIPE) {
	if (td_random(td)) {
	log_err("fio: can't seek on pipes (no random io)\n");
	goto err;
	}
	}

	if (td->io_ops->flags & FIO_DISKLESSIO)
	goto done;

	if (td->o.invalidate_cache && file_invalidate_cache(td, f))
	goto err;

	if (td->o.fadvise_hint &&
	(f->filetype == FIO_TYPE_BD \|\| f->filetype == FIO_TYPE_FILE)) {
	int flags;

	if (td_random(td))
	flags = POSIX_FADV_RANDOM;
	else
	flags = POSIX_FADV_SEQUENTIAL;

	if (posix_fadvise(f->fd, f->file_offset, f->io_size, flags) < 0) {
	td_verror(td, errno, "fadvise");
	goto err;
	}
	}

	#ifdef FIO_OS_DIRECTIO
	/*
	* Some OS's have a distinct call to mark the file non-buffered,
	* instead of using O_DIRECT (Solaris)
	*/
	if (td->o.odirect) {
	int ret = fio_set_odirect(f->fd);

	if (ret) {
	td_verror(td, ret, "fio_set_odirect");
	log_err("fio: the file system does not seem to support direct IO\n");
	goto err;
	}
	}
	#endif

	done:
	log_file(td, f, FIO_LOG_OPEN_FILE);
	return 0;
	err:
	disk_util_dec(f->du);
	if (td->io_ops->close_file)
	td->io_ops->close_file(td, f);
	return 1;
	}

	int td_io_close_file(struct thread_data td, struct fio_file f)
	{
	if (!fio_file_closing(f))
	log_file(td, f, FIO_LOG_CLOSE_FILE);

	/*
	* mark as closing, do real close when last io on it has completed
	*/
	fio_file_set_closing(f);

	disk_util_dec(f->du);
	unlock_file_all(td, f);

	return put_file(td, f);
	}

	int td_io_get_file_size(struct thread_data td, struct fio_file f)
	{
	if (!td->io_ops->get_file_size)
	return 0;

	return td->io_ops->get_file_size(td, f);
	}

	static int do_sync_file_range(struct thread_data td, struct fio_file f)
	{
	off64_t offset, nbytes;

	offset = f->first_write;
	nbytes = f->last_write - f->first_write;

	if (!nbytes)
	return 0;

	return sync_file_range(f->fd, offset, nbytes, td->o.sync_file_range);
	}

	int do_io_u_sync(struct thread_data td, struct io_u io_u)
	{
	int ret;

	if (io_u->ddir == DDIR_SYNC) {
	ret = fsync(io_u->file->fd);
	} else if (io_u->ddir == DDIR_DATASYNC) {
	#ifdef FIO_HAVE_FDATASYNC
	ret = fdatasync(io_u->file->fd);
	#else
	ret = io_u->xfer_buflen;
	io_u->error = EINVAL;
	#endif
	} else if (io_u->ddir == DDIR_SYNC_FILE_RANGE)
	ret = do_sync_file_range(td, io_u->file);
	else {
	ret = io_u->xfer_buflen;
	io_u->error = EINVAL;
	}

	if (ret < 0)
	io_u->error = errno;

	return ret;
	}

	int do_io_u_trim(struct thread_data td, struct io_u io_u)
	{
	#ifndef FIO_HAVE_TRIM
	io_u->error = EINVAL;
	return 0;
	#else
	struct fio_file *f = io_u->file;
	int ret;

	ret = os_trim(f->fd, io_u->offset, io_u->xfer_buflen);
	if (!ret)
	return io_u->xfer_buflen;;

	io_u->error = ret;
	return 0;
	#endif
	}

	int fio_show_ioengine_help(const char *engine)
	{
	struct flist_head *entry;
	struct thread_data td;
	char *sep;
	int ret = 1;

	if (!engine \|\| !*engine) {
	log_info("Available IO engines:\n");
	flist_for_each(entry, &engine_list) {
	td.io_ops = flist_entry(entry, struct ioengine_ops,
	list);
	log_info("\t%s\n", td.io_ops->name);
	}
	return 0;
	}
	sep = strchr(engine, ',');
	if (sep) {
	*sep = 0;
	sep++;
	}

	memset(&td, 0, sizeof(td));

	td.io_ops = load_ioengine(&td, engine);
	if (!td.io_ops) {
	log_info("IO engine %s not found\n", engine);
	return 1;
	}

	if (td.io_ops->options)
	ret = show_cmd_help(td.io_ops->options, sep);
	else
	log_info("IO engine %s has no options\n", td.io_ops->name);

	free_ioengine(&td);

	return ret;
	}