blktrace.c - platform/external/fio - Git at Google

 /*
  * blktrace support code for fio
  */
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <dirent.h>

 #include "flist.h"
 #include "fio.h"
 #include "blktrace_api.h"
 #include "lib/linux-dev-lookup.h"

 #define TRACE_FIFO_SIZE	8192

 /*
  * fifo refill frontend, to avoid reading data in trace sized bites
  */
 static int refill_fifo(struct thread_data *td, struct fifo *fifo, int fd)
 {
 	char buf[TRACE_FIFO_SIZE];
 	unsigned int total;
 	int ret;

 	total = sizeof(buf);
 	if (total > fifo_room(fifo))
 		total = fifo_room(fifo);

 	ret = read(fd, buf, total);
 	if (ret < 0) {
 		td_verror(td, errno, "read blktrace file");
 		return -1;
 	}

 	if (ret > 0)
 		ret = fifo_put(fifo, buf, ret);

 	dprint(FD_BLKTRACE, "refill: filled %d bytes\n", ret);
 	return ret;
 }

 /*
  * Retrieve 'len' bytes from the fifo, refilling if necessary.
  */
 static int trace_fifo_get(struct thread_data *td, struct fifo *fifo, int fd,
 			  void *buf, unsigned int len)
 {
 	if (fifo_len(fifo) < len) {
 		int ret = refill_fifo(td, fifo, fd);

 		if (ret < 0)
 			return ret;
 	}

 	return fifo_get(fifo, buf, len);
 }

 /*
  * Just discard the pdu by seeking past it.
  */
 static int discard_pdu(struct thread_data *td, struct fifo *fifo, int fd,
 		       struct blk_io_trace *t)
 {
 	if (t->pdu_len == 0)
 		return 0;

 	dprint(FD_BLKTRACE, "discard pdu len %u\n", t->pdu_len);
 	return trace_fifo_get(td, fifo, fd, NULL, t->pdu_len);
 }

 /*
  * Check if this is a blktrace binary data file. We read a single trace
  * into memory and check for the magic signature.
  */
 int is_blktrace(const char *filename, int *need_swap)
 {
 	struct blk_io_trace t;
 	int fd, ret;

 	fd = open(filename, O_RDONLY);
 	if (fd < 0)
 		return 0;

 	ret = read(fd, &t, sizeof(t));
 	close(fd);

 	if (ret < 0) {
 		perror("read blktrace");
 		return 0;
 	} else if (ret != sizeof(t)) {
 		log_err("fio: short read on blktrace file\n");
 		return 0;
 	}

 	if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
 		*need_swap = 0;
 		return 1;
 	}

 	/*
 	 * Maybe it needs to be endian swapped...
 	 */
 	t.magic = fio_swap32(t.magic);
 	if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
 		*need_swap = 1;
 		return 1;
 	}

 	return 0;
 }

 #define FMINORBITS	20
 #define FMINORMASK	((1U << FMINORBITS) - 1)
 #define FMAJOR(dev)	((unsigned int) ((dev) >> FMINORBITS))
 #define FMINOR(dev)	((unsigned int) ((dev) & FMINORMASK))

 static void trace_add_open_close_event(struct thread_data *td, int fileno, enum file_log_act action)
 {
 	struct io_piece *ipo;

 	ipo = calloc(1, sizeof(*ipo));
 	init_ipo(ipo);

 	ipo->ddir = DDIR_INVAL;
 	ipo->fileno = fileno;
 	ipo->file_action = action;
 	flist_add_tail(&ipo->list, &td->io_log_list);
 }

 static int trace_add_file(struct thread_data *td, __u32 device)
 {
 	static unsigned int last_maj, last_min, last_fileno;
 	unsigned int maj = FMAJOR(device);
 	unsigned int min = FMINOR(device);
 	struct fio_file *f;
 	char dev[256];
 	unsigned int i;

 	if (last_maj == maj && last_min == min)
 		return last_fileno;

 	last_maj = maj;
 	last_min = min;

 	/*
 	 * check for this file in our list
 	 */
 	for_each_file(td, f, i)
 		if (f->major == maj && f->minor == min) {
 			last_fileno = f->fileno;
 			return last_fileno;
 		}

 	strcpy(dev, "/dev");
 	if (blktrace_lookup_device(td->o.replay_redirect, dev, maj, min)) {
 		int fileno;

 		if (td->o.replay_redirect)
 			dprint(FD_BLKTRACE, "device lookup: %d/%d\n overridden"
 					" with: %s\n", maj, min,
 					td->o.replay_redirect);
 		else
 			dprint(FD_BLKTRACE, "device lookup: %d/%d\n", maj, min);

 		dprint(FD_BLKTRACE, "add devices %s\n", dev);
 		fileno = add_file_exclusive(td, dev);
 		td->o.open_files++;
 		td->files[fileno]->major = maj;
 		td->files[fileno]->minor = min;
 		trace_add_open_close_event(td, fileno, FIO_LOG_OPEN_FILE);
 		last_fileno = fileno;
 	}

 	return last_fileno;
 }

 /*
  * Store blk_io_trace data in an ipo for later retrieval.
  */
 static void store_ipo(struct thread_data *td, unsigned long long offset,
 		      unsigned int bytes, int rw, unsigned long long ttime,
 		      int fileno)
 {
 	struct io_piece *ipo = malloc(sizeof(*ipo));

 	init_ipo(ipo);

 	/*
 	 * the 512 is wrong here, it should be the hardware sector size...
 	 */
 	ipo->offset = offset * 512;
 	ipo->len = bytes;
 	ipo->delay = ttime / 1000;
 	if (rw)
 		ipo->ddir = DDIR_WRITE;
 	else
 		ipo->ddir = DDIR_READ;
 	ipo->fileno = fileno;

 	dprint(FD_BLKTRACE, "store ddir=%d, off=%llu, len=%lu, delay=%lu\n",
 							ipo->ddir, ipo->offset,
 							ipo->len, ipo->delay);
 	queue_io_piece(td, ipo);
 }

 static void handle_trace_notify(struct blk_io_trace *t)
 {
 	switch (t->action) {
 	case BLK_TN_PROCESS:
 		dprint(FD_BLKTRACE, "got process notify: %x, %d\n",
 				t->action, t->pid);
 		break;
 	case BLK_TN_TIMESTAMP:
 		dprint(FD_BLKTRACE, "got timestamp notify: %x, %d\n",
 				t->action, t->pid);
 		break;
 	case BLK_TN_MESSAGE:
 		break;
 	default:
 		dprint(FD_BLKTRACE, "unknown trace act %x\n", t->action);
 		break;
 	}
 }

 static void handle_trace_discard(struct thread_data *td,
 				 struct blk_io_trace *t,
 				 unsigned long long ttime,
 				 unsigned long *ios, unsigned int *bs)
 {
 	struct io_piece *ipo = malloc(sizeof(*ipo));
 	int fileno;

 	init_ipo(ipo);
 	fileno = trace_add_file(td, t->device);

 	ios[DDIR_TRIM]++;
 	if (t->bytes > bs[DDIR_TRIM])
 		bs[DDIR_TRIM] = t->bytes;

 	td->o.size += t->bytes;

 	memset(ipo, 0, sizeof(*ipo));
 	INIT_FLIST_HEAD(&ipo->list);

 	/*
 	 * the 512 is wrong here, it should be the hardware sector size...
 	 */
 	ipo->offset = t->sector * 512;
 	ipo->len = t->bytes;
 	ipo->delay = ttime / 1000;
 	ipo->ddir = DDIR_TRIM;
 	ipo->fileno = fileno;

 	dprint(FD_BLKTRACE, "store discard, off=%llu, len=%lu, delay=%lu\n",
 							ipo->offset, ipo->len,
 							ipo->delay);
 	queue_io_piece(td, ipo);
 }

 static void handle_trace_fs(struct thread_data *td, struct blk_io_trace *t,
 			    unsigned long long ttime, unsigned long *ios,
 			    unsigned int *bs)
 {
 	int rw;
 	int fileno;

 	fileno = trace_add_file(td, t->device);

 	rw = (t->action & BLK_TC_ACT(BLK_TC_WRITE)) != 0;

 	if (t->bytes > bs[rw])
 		bs[rw] = t->bytes;

 	ios[rw]++;
 	td->o.size += t->bytes;
 	store_ipo(td, t->sector, t->bytes, rw, ttime, fileno);
 }

 /*
  * We only care for queue traces, most of the others are side effects
  * due to internal workings of the block layer.
  */
 static void handle_trace(struct thread_data *td, struct blk_io_trace *t,
 			 unsigned long *ios, unsigned int *bs)
 {
 	static unsigned long long last_ttime;
 	unsigned long long delay;

 	if ((t->action & 0xffff) != __BLK_TA_QUEUE)
 		return;

 	if (!(t->action & BLK_TC_ACT(BLK_TC_NOTIFY))) {
 		if (!last_ttime || td->o.no_stall) {
 			last_ttime = t->time;
 			delay = 0;
 		} else {
 			delay = t->time - last_ttime;
 			last_ttime = t->time;
 		}
 	}

 	if (t->action & BLK_TC_ACT(BLK_TC_NOTIFY))
 		handle_trace_notify(t);
 	else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
 		handle_trace_discard(td, t, delay, ios, bs);
 	else
 		handle_trace_fs(td, t, delay, ios, bs);
 }

 static void byteswap_trace(struct blk_io_trace *t)
 {
 	t->magic = fio_swap32(t->magic);
 	t->sequence = fio_swap32(t->sequence);
 	t->time = fio_swap64(t->time);
 	t->sector = fio_swap64(t->sector);
 	t->bytes = fio_swap32(t->bytes);
 	t->action = fio_swap32(t->action);
 	t->pid = fio_swap32(t->pid);
 	t->device = fio_swap32(t->device);
 	t->cpu = fio_swap32(t->cpu);
 	t->error = fio_swap16(t->error);
 	t->pdu_len = fio_swap16(t->pdu_len);
 }

 static int t_is_write(struct blk_io_trace *t)
 {
 	return (t->action & BLK_TC_ACT(BLK_TC_WRITE | BLK_TC_DISCARD)) != 0;
 }

 /*
  * Load a blktrace file by reading all the blk_io_trace entries, and storing
  * them as io_pieces like the fio text version would do.
  */
 int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 {
 	struct blk_io_trace t;
 	unsigned long ios[DDIR_RWDIR_CNT], skipped_writes;
 	unsigned int rw_bs[DDIR_RWDIR_CNT];
 	struct fifo *fifo;
 	int fd, i, old_state;
 	struct fio_file *f;
 	int this_depth, depth;

 	fd = open(filename, O_RDONLY);
 	if (fd < 0) {
 		td_verror(td, errno, "open blktrace file");
 		return 1;
 	}

 	fifo = fifo_alloc(TRACE_FIFO_SIZE);

 	old_state = td_bump_runstate(td, TD_SETTING_UP);

 	td->o.size = 0;

 	ios[0] = ios[1] = 0;
 	rw_bs[0] = rw_bs[1] = 0;
 	skipped_writes = 0;
 	this_depth = depth = 0;
 	do {
 		int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));

 		if (ret < 0)
 			goto err;
 		else if (!ret)
 			break;
 		else if (ret < (int) sizeof(t)) {
 			log_err("fio: short fifo get\n");
 			break;
 		}

 		if (need_swap)
 			byteswap_trace(&t);

 		if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) {
 			log_err("fio: bad magic in blktrace data: %x\n",
 								t.magic);
 			goto err;
 		}
 		if ((t.magic & 0xff) != BLK_IO_TRACE_VERSION) {
 			log_err("fio: bad blktrace version %d\n",
 								t.magic & 0xff);
 			goto err;
 		}
 		ret = discard_pdu(td, fifo, fd, &t);
 		if (ret < 0) {
 			td_verror(td, ret, "blktrace lseek");
 			goto err;
 		} else if (t.pdu_len != ret) {
 			log_err("fio: discarded %d of %d\n", ret, t.pdu_len);
 			goto err;
 		}
 		if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
 			if ((t.action & 0xffff) == __BLK_TA_QUEUE)
 				this_depth++;
 			else if ((t.action & 0xffff) == __BLK_TA_COMPLETE) {
 				depth = max(depth, this_depth);
 				this_depth = 0;
 			}

 			if (t_is_write(&t) && read_only) {
 				skipped_writes++;
 				continue;
 			}
 		}

 		handle_trace(td, &t, ios, rw_bs);
 	} while (1);

 	for (i = 0; i < td->files_index; i++) {
 		f = td->files[i];
 		trace_add_open_close_event(td, f->fileno, FIO_LOG_CLOSE_FILE);
 	}

 	fifo_free(fifo);
 	close(fd);

 	td_restore_runstate(td, old_state);

 	if (!td->files_index) {
 		log_err("fio: did not find replay device(s)\n");
 		return 1;
 	}

 	/*
 	 * For stacked devices, we don't always get a COMPLETE event so
 	 * the depth grows to insane values. Limit it to something sane(r).
 	 */
 	if (!depth || depth > 1024)
 		depth = 1024;

 	if (skipped_writes)
 		log_err("fio: %s skips replay of %lu writes due to read-only\n",
 						td->o.name, skipped_writes);

 	if (!ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 		log_err("fio: found no ios in blktrace data\n");
 		return 1;
 	} else if (ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 		td->o.td_ddir = TD_DDIR_READ;
 		td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 	} else if (!ios[DDIR_READ] && ios[DDIR_WRITE]) {
 		td->o.td_ddir = TD_DDIR_WRITE;
 		td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 	} else {
 		td->o.td_ddir = TD_DDIR_RW;
 		td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 		td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 		td->o.max_bs[DDIR_TRIM] = rw_bs[DDIR_TRIM];
 	}

 	/*
 	 * We need to do direct/raw ios to the device, to avoid getting
 	 * read-ahead in our way.
 	 */
 	td->o.odirect = 1;

 	/*
 	 * we don't know if this option was set or not. it defaults to 1,
 	 * so we'll just guess that we should override it if it's still 1
 	 */
 	if (td->o.iodepth != 1)
 		td->o.iodepth = depth;

 	return 0;
 err:
 	close(fd);
 	fifo_free(fifo);
 	return 1;
 }
	/*
	* blktrace support code for fio
	*/
	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/stat.h>
	#include <dirent.h>

	#include "flist.h"
	#include "fio.h"
	#include "blktrace_api.h"
	#include "lib/linux-dev-lookup.h"

	#define TRACE_FIFO_SIZE 8192

	/*
	* fifo refill frontend, to avoid reading data in trace sized bites
	*/
	static int refill_fifo(struct thread_data td, struct fifo fifo, int fd)
	{
	char buf[TRACE_FIFO_SIZE];
	unsigned int total;
	int ret;

	total = sizeof(buf);
	if (total > fifo_room(fifo))
	total = fifo_room(fifo);

	ret = read(fd, buf, total);
	if (ret < 0) {
	td_verror(td, errno, "read blktrace file");
	return -1;
	}

	if (ret > 0)
	ret = fifo_put(fifo, buf, ret);

	dprint(FD_BLKTRACE, "refill: filled %d bytes\n", ret);
	return ret;
	}

	/*
	* Retrieve 'len' bytes from the fifo, refilling if necessary.
	*/
	static int trace_fifo_get(struct thread_data td, struct fifo fifo, int fd,
	void *buf, unsigned int len)
	{
	if (fifo_len(fifo) < len) {
	int ret = refill_fifo(td, fifo, fd);

	if (ret < 0)
	return ret;
	}

	return fifo_get(fifo, buf, len);
	}

	/*
	* Just discard the pdu by seeking past it.
	*/
	static int discard_pdu(struct thread_data td, struct fifo fifo, int fd,
	struct blk_io_trace *t)
	{
	if (t->pdu_len == 0)
	return 0;

	dprint(FD_BLKTRACE, "discard pdu len %u\n", t->pdu_len);
	return trace_fifo_get(td, fifo, fd, NULL, t->pdu_len);
	}

	/*
	* Check if this is a blktrace binary data file. We read a single trace
	* into memory and check for the magic signature.
	*/
	int is_blktrace(const char filename, int need_swap)
	{
	struct blk_io_trace t;
	int fd, ret;

	fd = open(filename, O_RDONLY);
	if (fd < 0)
	return 0;

	ret = read(fd, &t, sizeof(t));
	close(fd);

	if (ret < 0) {
	perror("read blktrace");
	return 0;
	} else if (ret != sizeof(t)) {
	log_err("fio: short read on blktrace file\n");
	return 0;
	}

	if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
	*need_swap = 0;
	return 1;
	}

	/*
	* Maybe it needs to be endian swapped...
	*/
	t.magic = fio_swap32(t.magic);
	if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
	*need_swap = 1;
	return 1;
	}

	return 0;
	}

	#define FMINORBITS 20
	#define FMINORMASK ((1U << FMINORBITS) - 1)
	#define FMAJOR(dev) ((unsigned int) ((dev) >> FMINORBITS))
	#define FMINOR(dev) ((unsigned int) ((dev) & FMINORMASK))

	static void trace_add_open_close_event(struct thread_data *td, int fileno, enum file_log_act action)
	{
	struct io_piece *ipo;

	ipo = calloc(1, sizeof(*ipo));
	init_ipo(ipo);

	ipo->ddir = DDIR_INVAL;
	ipo->fileno = fileno;
	ipo->file_action = action;
	flist_add_tail(&ipo->list, &td->io_log_list);
	}

	static int trace_add_file(struct thread_data *td, __u32 device)
	{
	static unsigned int last_maj, last_min, last_fileno;
	unsigned int maj = FMAJOR(device);
	unsigned int min = FMINOR(device);
	struct fio_file *f;
	char dev[256];
	unsigned int i;

	if (last_maj == maj && last_min == min)
	return last_fileno;

	last_maj = maj;
	last_min = min;

	/*
	* check for this file in our list
	*/
	for_each_file(td, f, i)
	if (f->major == maj && f->minor == min) {
	last_fileno = f->fileno;
	return last_fileno;
	}

	strcpy(dev, "/dev");
	if (blktrace_lookup_device(td->o.replay_redirect, dev, maj, min)) {
	int fileno;

	if (td->o.replay_redirect)
	dprint(FD_BLKTRACE, "device lookup: %d/%d\n overridden"
	" with: %s\n", maj, min,
	td->o.replay_redirect);
	else
	dprint(FD_BLKTRACE, "device lookup: %d/%d\n", maj, min);

	dprint(FD_BLKTRACE, "add devices %s\n", dev);
	fileno = add_file_exclusive(td, dev);
	td->o.open_files++;
	td->files[fileno]->major = maj;
	td->files[fileno]->minor = min;
	trace_add_open_close_event(td, fileno, FIO_LOG_OPEN_FILE);
	last_fileno = fileno;
	}

	return last_fileno;
	}

	/*
	* Store blk_io_trace data in an ipo for later retrieval.
	*/
	static void store_ipo(struct thread_data *td, unsigned long long offset,
	unsigned int bytes, int rw, unsigned long long ttime,
	int fileno)
	{
	struct io_piece ipo = malloc(sizeof(ipo));

	init_ipo(ipo);

	/*
	* the 512 is wrong here, it should be the hardware sector size...
	*/
	ipo->offset = offset * 512;
	ipo->len = bytes;
	ipo->delay = ttime / 1000;
	if (rw)
	ipo->ddir = DDIR_WRITE;
	else
	ipo->ddir = DDIR_READ;
	ipo->fileno = fileno;

	dprint(FD_BLKTRACE, "store ddir=%d, off=%llu, len=%lu, delay=%lu\n",
	ipo->ddir, ipo->offset,
	ipo->len, ipo->delay);
	queue_io_piece(td, ipo);
	}

	static void handle_trace_notify(struct blk_io_trace *t)
	{
	switch (t->action) {
	case BLK_TN_PROCESS:
	dprint(FD_BLKTRACE, "got process notify: %x, %d\n",
	t->action, t->pid);
	break;
	case BLK_TN_TIMESTAMP:
	dprint(FD_BLKTRACE, "got timestamp notify: %x, %d\n",
	t->action, t->pid);
	break;
	case BLK_TN_MESSAGE:
	break;
	default:
	dprint(FD_BLKTRACE, "unknown trace act %x\n", t->action);
	break;
	}
	}

	static void handle_trace_discard(struct thread_data *td,
	struct blk_io_trace *t,
	unsigned long long ttime,
	unsigned long ios, unsigned int bs)
	{
	struct io_piece ipo = malloc(sizeof(ipo));
	int fileno;

	init_ipo(ipo);
	fileno = trace_add_file(td, t->device);

	ios[DDIR_TRIM]++;
	if (t->bytes > bs[DDIR_TRIM])
	bs[DDIR_TRIM] = t->bytes;

	td->o.size += t->bytes;

	memset(ipo, 0, sizeof(*ipo));
	INIT_FLIST_HEAD(&ipo->list);

	/*
	* the 512 is wrong here, it should be the hardware sector size...
	*/
	ipo->offset = t->sector * 512;
	ipo->len = t->bytes;
	ipo->delay = ttime / 1000;
	ipo->ddir = DDIR_TRIM;
	ipo->fileno = fileno;

	dprint(FD_BLKTRACE, "store discard, off=%llu, len=%lu, delay=%lu\n",
	ipo->offset, ipo->len,
	ipo->delay);
	queue_io_piece(td, ipo);
	}

	static void handle_trace_fs(struct thread_data td, struct blk_io_trace t,
	unsigned long long ttime, unsigned long *ios,
	unsigned int *bs)
	{
	int rw;
	int fileno;

	fileno = trace_add_file(td, t->device);

	rw = (t->action & BLK_TC_ACT(BLK_TC_WRITE)) != 0;

	if (t->bytes > bs[rw])
	bs[rw] = t->bytes;

	ios[rw]++;
	td->o.size += t->bytes;
	store_ipo(td, t->sector, t->bytes, rw, ttime, fileno);
	}

	/*
	* We only care for queue traces, most of the others are side effects
	* due to internal workings of the block layer.
	*/
	static void handle_trace(struct thread_data td, struct blk_io_trace t,
	unsigned long ios, unsigned int bs)
	{
	static unsigned long long last_ttime;
	unsigned long long delay;

	if ((t->action & 0xffff) != __BLK_TA_QUEUE)
	return;

	if (!(t->action & BLK_TC_ACT(BLK_TC_NOTIFY))) {
	if (!last_ttime \|\| td->o.no_stall) {
	last_ttime = t->time;
	delay = 0;
	} else {
	delay = t->time - last_ttime;
	last_ttime = t->time;
	}
	}

	if (t->action & BLK_TC_ACT(BLK_TC_NOTIFY))
	handle_trace_notify(t);
	else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
	handle_trace_discard(td, t, delay, ios, bs);
	else
	handle_trace_fs(td, t, delay, ios, bs);
	}

	static void byteswap_trace(struct blk_io_trace *t)
	{
	t->magic = fio_swap32(t->magic);
	t->sequence = fio_swap32(t->sequence);
	t->time = fio_swap64(t->time);
	t->sector = fio_swap64(t->sector);
	t->bytes = fio_swap32(t->bytes);
	t->action = fio_swap32(t->action);
	t->pid = fio_swap32(t->pid);
	t->device = fio_swap32(t->device);
	t->cpu = fio_swap32(t->cpu);
	t->error = fio_swap16(t->error);
	t->pdu_len = fio_swap16(t->pdu_len);
	}

	static int t_is_write(struct blk_io_trace *t)
	{
	return (t->action & BLK_TC_ACT(BLK_TC_WRITE \| BLK_TC_DISCARD)) != 0;
	}

	/*
	* Load a blktrace file by reading all the blk_io_trace entries, and storing
	* them as io_pieces like the fio text version would do.
	*/
	int load_blktrace(struct thread_data td, const char filename, int need_swap)
	{
	struct blk_io_trace t;
	unsigned long ios[DDIR_RWDIR_CNT], skipped_writes;
	unsigned int rw_bs[DDIR_RWDIR_CNT];
	struct fifo *fifo;
	int fd, i, old_state;
	struct fio_file *f;
	int this_depth, depth;

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
	td_verror(td, errno, "open blktrace file");
	return 1;
	}

	fifo = fifo_alloc(TRACE_FIFO_SIZE);

	old_state = td_bump_runstate(td, TD_SETTING_UP);

	td->o.size = 0;

	ios[0] = ios[1] = 0;
	rw_bs[0] = rw_bs[1] = 0;
	skipped_writes = 0;
	this_depth = depth = 0;
	do {
	int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));

	if (ret < 0)
	goto err;
	else if (!ret)
	break;
	else if (ret < (int) sizeof(t)) {
	log_err("fio: short fifo get\n");
	break;
	}

	if (need_swap)
	byteswap_trace(&t);

	if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) {
	log_err("fio: bad magic in blktrace data: %x\n",
	t.magic);
	goto err;
	}
	if ((t.magic & 0xff) != BLK_IO_TRACE_VERSION) {
	log_err("fio: bad blktrace version %d\n",
	t.magic & 0xff);
	goto err;
	}
	ret = discard_pdu(td, fifo, fd, &t);
	if (ret < 0) {
	td_verror(td, ret, "blktrace lseek");
	goto err;
	} else if (t.pdu_len != ret) {
	log_err("fio: discarded %d of %d\n", ret, t.pdu_len);
	goto err;
	}
	if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
	if ((t.action & 0xffff) == __BLK_TA_QUEUE)
	this_depth++;
	else if ((t.action & 0xffff) == __BLK_TA_COMPLETE) {
	depth = max(depth, this_depth);
	this_depth = 0;
	}

	if (t_is_write(&t) && read_only) {
	skipped_writes++;
	continue;
	}
	}

	handle_trace(td, &t, ios, rw_bs);
	} while (1);

	for (i = 0; i < td->files_index; i++) {
	f = td->files[i];
	trace_add_open_close_event(td, f->fileno, FIO_LOG_CLOSE_FILE);
	}

	fifo_free(fifo);
	close(fd);

	td_restore_runstate(td, old_state);

	if (!td->files_index) {
	log_err("fio: did not find replay device(s)\n");
	return 1;
	}

	/*
	* For stacked devices, we don't always get a COMPLETE event so
	* the depth grows to insane values. Limit it to something sane(r).
	*/
	if (!depth \|\| depth > 1024)
	depth = 1024;

	if (skipped_writes)
	log_err("fio: %s skips replay of %lu writes due to read-only\n",
	td->o.name, skipped_writes);

	if (!ios[DDIR_READ] && !ios[DDIR_WRITE]) {
	log_err("fio: found no ios in blktrace data\n");
	return 1;
	} else if (ios[DDIR_READ] && !ios[DDIR_WRITE]) {
	td->o.td_ddir = TD_DDIR_READ;
	td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
	} else if (!ios[DDIR_READ] && ios[DDIR_WRITE]) {
	td->o.td_ddir = TD_DDIR_WRITE;
	td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
	} else {
	td->o.td_ddir = TD_DDIR_RW;
	td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
	td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
	td->o.max_bs[DDIR_TRIM] = rw_bs[DDIR_TRIM];
	}

	/*
	* We need to do direct/raw ios to the device, to avoid getting
	* read-ahead in our way.
	*/
	td->o.odirect = 1;

	/*
	* we don't know if this option was set or not. it defaults to 1,
	* so we'll just guess that we should override it if it's still 1
	*/
	if (td->o.iodepth != 1)
	td->o.iodepth = depth;

	return 0;
	err:
	close(fd);
	fifo_free(fifo);
	return 1;
	}