[fio.git] / verify.c

/*
 * IO verification helpers
 */
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <assert.h>

#include "fio.h"

static void fill_random_bytes(struct thread_data *td, void *p, unsigned int len)
{
	unsigned int todo;
	int r;

	while (len) {
		r = os_random_long(&td->verify_state);

		/*
		 * lrand48_r seems to be broken and only fill the bottom
		 * 32-bits, even on 64-bit archs with 64-bit longs
		 */
		todo = sizeof(r);
		if (todo > len)
			todo = len;

		memcpy(p, &r, todo);

		len -= todo;
		p += todo;
	}
}

static void fill_pattern(struct thread_data *td, void *p, unsigned int len)
{
	switch (td->o.verify_pattern_bytes) {
	case 0:
		fill_random_bytes(td, p, len);
		break;
	case 1:
		memset(p, td->o.verify_pattern, len);
		break;
	case 2:
	case 3:
	case 4: {
		unsigned int pattern = td->o.verify_pattern;
		unsigned int i = 0;
		unsigned char c1, c2, c3, c4;
		unsigned char *b = p;

		c1 = pattern & 0xff;
		pattern >>= 8;
		c2 = pattern & 0xff;
		pattern >>= 8;
		c3 = pattern & 0xff;
		pattern >>= 8;
		c4 = pattern & 0xff;

		while (i < len) {
			b[i++] = c1;
			if (i == len)
				break;
			b[i++] = c2;
			if (td->o.verify_pattern_bytes == 2 || i == len)
				continue;
			b[i++] = c3;
			if (td->o.verify_pattern_bytes == 3 || i == len)
				continue;
			b[i++] = c4;
		}
		break;
		}
	}
}

static void memswp(void* buf1, void* buf2, unsigned int len)
{
	struct verify_header swap;

	memcpy(&swap, buf1, len);
	memcpy(buf1, buf2, len);
	memcpy(buf2, &swap, len);
}

static void hexdump(void *buffer, int len)
{
	unsigned char *p = buffer;
	int i;

	for (i = 0; i < len; i++)
		log_info("%02x", p[i]);
	log_info("\n");
}

/*
 * Return data area 'header_num'
 */
static inline void *io_u_verify_off(struct verify_header *hdr,
				    struct io_u *io_u,
				    unsigned char header_num)
{
	return io_u->buf + sizeof(*hdr) + header_num * hdr->len;
}

static int verify_io_u_crc7(struct verify_header *hdr, struct io_u *io_u,
                            unsigned char header_num)
{
	void *p = io_u_verify_off(hdr, io_u, header_num);
	unsigned char c;

	c = crc7(p, hdr->len - sizeof(*hdr));

	if (c != hdr->crc7) {
		log_err("crc7: verify failed at %llu/%u\n",
		                io_u->offset + header_num * hdr->len,
				hdr->len);
		log_err("crc7: wanted %x, got %x\n", hdr->crc7, c);
		return 1;
	}

	return 0;
}

static int verify_io_u_crc16(struct verify_header *hdr, struct io_u *io_u,
                             unsigned int header_num)
{
	void *p = io_u_verify_off(hdr, io_u, header_num);
	unsigned short c;

	c = crc16(p, hdr->len - sizeof(*hdr));

	if (c != hdr->crc16) {
		log_err("crc16: verify failed at %llu/%u\n",
		                io_u->offset + header_num * hdr->len,
				hdr->len);
		log_err("crc16: wanted %x, got %x\n", hdr->crc16, c);
		return 1;
	}

	return 0;
}

static int verify_io_u_crc64(struct verify_header *hdr, struct io_u *io_u,
                             unsigned int header_num)
{
	void *p = io_u_verify_off(hdr, io_u, header_num);
	unsigned long long c;

	c = crc64(p, hdr->len - sizeof(*hdr));

	if (c != hdr->crc64) {
		log_err("crc64: verify failed at %llu/%u\n",
				io_u->offset + header_num * hdr->len,
				hdr->len);
		log_err("crc64: wanted %llx, got %llx\n", hdr->crc64, c);
		return 1;
	}

	return 0;
}

static int verify_io_u_crc32(struct verify_header *hdr, struct io_u *io_u,
		             unsigned int header_num)
{
	void *p = io_u_verify_off(hdr, io_u, header_num);
	unsigned long c;

	c = crc32(p, hdr->len - sizeof(*hdr));

	if (c != hdr->crc32) {
		log_err("crc32: verify failed at %llu/%u\n",
		                io_u->offset + header_num * hdr->len,
				hdr->len);
		log_err("crc32: wanted %lx, got %lx\n", hdr->crc32, c);
		return 1;
	}

	return 0;
}

static int verify_io_u_md5(struct verify_header *hdr, struct io_u *io_u,
		           unsigned int header_num)
{
	void *p = io_u_verify_off(hdr, io_u, header_num);
	uint32_t hash[MD5_HASH_WORDS];
	struct md5_ctx md5_ctx = {
		.hash = hash,
	};

	memset(md5_ctx.hash, 0, sizeof(hdr->md5_digest));
	md5_update(&md5_ctx, p, hdr->len - sizeof(*hdr));

	if (memcmp(hdr->md5_digest, md5_ctx.hash, sizeof(hash))) {
		log_err("md5: verify failed at %llu/%u\n",
		              io_u->offset + header_num * hdr->len,
		              hdr->len);
		hexdump(hdr->md5_digest, sizeof(hdr->md5_digest));
		hexdump(md5_ctx.hash, sizeof(hash));
		return 1;
	}

	return 0;
}

int verify_io_u(struct thread_data *td, struct io_u *io_u)
{
	struct verify_header *hdr;
	unsigned int hdr_inc, hdr_num = 0;
	void *p;
	int ret;

	if (td->o.verify == VERIFY_NULL || io_u->ddir != DDIR_READ)
		return 0;

	hdr_inc = io_u->buflen;
	if (td->o.verify_interval)
		hdr_inc = td->o.verify_interval;

	for (p = io_u->buf; p < io_u->buf + io_u->buflen; p += hdr_inc) {
		if (td->o.verify_offset)
			memswp(p, p + td->o.verify_offset, sizeof(*hdr));

		hdr = p;

		if (hdr->fio_magic != FIO_HDR_MAGIC) {
			log_err("Bad verify header %x\n", hdr->fio_magic);
			return EIO;
		}

		switch (hdr->verify_type) {
		case VERIFY_MD5:
			ret = verify_io_u_md5(hdr, io_u, hdr_num);
			break;
		case VERIFY_CRC64:
			ret = verify_io_u_crc64(hdr, io_u, hdr_num);
			break;
		case VERIFY_CRC32:
			ret = verify_io_u_crc32(hdr, io_u, hdr_num);
			break;
		case VERIFY_CRC16:
			ret = verify_io_u_crc16(hdr, io_u, hdr_num);
			break;
		case VERIFY_CRC7:
			ret = verify_io_u_crc7(hdr, io_u, hdr_num);
			break;
		default:
			log_err("Bad verify type %u\n", hdr->verify_type);
			ret = 1;
		}
		hdr_num++;
	}

	return 0;
}

static void fill_crc7(struct verify_header *hdr, void *p, unsigned int len)
{
	hdr->crc7 = crc7(p, len);
}

static void fill_crc16(struct verify_header *hdr, void *p, unsigned int len)
{
	hdr->crc16 = crc16(p, len);
}

static void fill_crc32(struct verify_header *hdr, void *p, unsigned int len)
{
	hdr->crc32 = crc32(p, len);
}

static void fill_crc64(struct verify_header *hdr, void *p, unsigned int len)
{
	hdr->crc64 = crc64(p, len);
}

static void fill_md5(struct verify_header *hdr, void *p, unsigned int len)
{
	struct md5_ctx md5_ctx = {
		.hash = (uint32_t *) hdr->md5_digest,
	};

	memset(md5_ctx.hash, 0, sizeof(hdr->md5_digest));
	md5_update(&md5_ctx, p, len);
}

/*
 * fill body of io_u->buf with random data and add a header with the
 * crc32 or md5 sum of that data.
 */
void populate_verify_io_u(struct thread_data *td, struct io_u *io_u)
{
	struct verify_header *hdr;
	void *p = io_u->buf, *data;
	unsigned int hdr_inc, data_len;

	if (td->o.verify == VERIFY_NULL)
		return;

	fill_pattern(td, p, io_u->buflen);

	hdr_inc = io_u->buflen;
	if (td->o.verify_interval)
		hdr_inc = td->o.verify_interval;
	data_len = hdr_inc - sizeof(*hdr);

	for (;p < io_u->buf + io_u->buflen; p += hdr_inc) {
		hdr = p;

		hdr->fio_magic = FIO_HDR_MAGIC;
		hdr->verify_type = td->o.verify;
		hdr->len = hdr_inc;

		data = p + sizeof(*hdr);
		switch (td->o.verify) {
		case VERIFY_MD5:
			fill_md5(hdr, data, data_len);
			break;
		case VERIFY_CRC64:
			fill_crc64(hdr, data, data_len);
			break;
		case VERIFY_CRC32:
			fill_crc32(hdr, data, data_len);
			break;
		case VERIFY_CRC16:
			fill_crc16(hdr, data, data_len);
			break;
		case VERIFY_CRC7:
			fill_crc7(hdr, data, data_len);
			break;
		default:
			log_err("fio: bad verify type: %d\n", td->o.verify);
			assert(0);
		}
		if (td->o.verify_offset)
			memswp(p, p + td->o.verify_offset, sizeof(*hdr));
	}
}

int get_next_verify(struct thread_data *td, struct io_u *io_u)
{
	struct io_piece *ipo = NULL;

	/*
	 * this io_u is from a requeue, we already filled the offsets
	 */
	if (io_u->file)
		return 0;

	if (!RB_EMPTY_ROOT(&td->io_hist_tree)) {
		struct rb_node *n = rb_first(&td->io_hist_tree);

		ipo = rb_entry(n, struct io_piece, rb_node);
		rb_erase(n, &td->io_hist_tree);
	} else if (!list_empty(&td->io_hist_list)) {
		ipo = list_entry(td->io_hist_list.next, struct io_piece, list);
		list_del(&ipo->list);
	}

	if (ipo) {
		io_u->offset = ipo->offset;
		io_u->buflen = ipo->len;
		io_u->file = ipo->file;

		if ((io_u->file->flags & FIO_FILE_OPEN) == 0) {
			int r = td_io_open_file(td, io_u->file);

			if (r)
				return 1;
		}

		get_file(ipo->file);
		assert(io_u->file->flags & FIO_FILE_OPEN);
		io_u->ddir = DDIR_READ;
		io_u->xfer_buf = io_u->buf;
		io_u->xfer_buflen = io_u->buflen;
		free(ipo);
		return 0;
	}

	return 1;
}
Commit	Line	Data
e29d1b70 JA	1	/*
	2	* IO verification helpers
	3	*/
	4	#include <unistd.h>
	5	#include <fcntl.h>
	6	#include <string.h>
97af62ce	7	#include <assert.h>
e29d1b70 JA	8
e29d1b70 JA	9	#include "fio.h"
e29d1b70	10
90059d65	11	static void fill_random_bytes(struct thread_data td, void p, unsigned int len)
e29d1b70 JA	12	{
e29d1b70 JA	13	unsigned int todo;
4c5946c6	14	int r;
e29d1b70 JA	15
e29d1b70 JA	16	while (len) {
4c5946c6	17	r = os_random_long(&td->verify_state);
e29d1b70 JA	18
	19	/*
	20	* lrand48_r seems to be broken and only fill the bottom
	21	* 32-bits, even on 64-bit archs with 64-bit longs
	22	*/
	23	todo = sizeof(r);
	24	if (todo > len)
	25	todo = len;
	26
	27	memcpy(p, &r, todo);
	28
	29	len -= todo;
	30	p += todo;
	31	}
	32	}
	33
90059d65 JA	34	static void fill_pattern(struct thread_data td, void p, unsigned int len)
	35	{
	36	switch (td->o.verify_pattern_bytes) {
	37	case 0:
	38	fill_random_bytes(td, p, len);
	39	break;
	40	case 1:
	41	memset(p, td->o.verify_pattern, len);
	42	break;
	43	case 2:
	44	case 3:
	45	case 4: {
	46	unsigned int pattern = td->o.verify_pattern;
	47	unsigned int i = 0;
	48	unsigned char c1, c2, c3, c4;
	49	unsigned char *b = p;
	50
	51	c1 = pattern & 0xff;
	52	pattern >>= 8;
	53	c2 = pattern & 0xff;
	54	pattern >>= 8;
	55	c3 = pattern & 0xff;
	56	pattern >>= 8;
	57	c4 = pattern & 0xff;
	58
	59	while (i < len) {
	60	b[i++] = c1;
	61	if (i == len)
	62	break;
	63	b[i++] = c2;
	64	if (td->o.verify_pattern_bytes == 2 \|\| i == len)
	65	continue;
	66	b[i++] = c3;
	67	if (td->o.verify_pattern_bytes == 3 \|\| i == len)
	68	continue;
	69	b[i++] = c4;
	70	}
	71	break;
	72	}
	73	}
	74	}
	75
	76	static void memswp(void* buf1, void* buf2, unsigned int len)
546a9142 SL	77	{
546a9142 SL	78	struct verify_header swap;
90059d65	79
546a9142 SL	80	memcpy(&swap, buf1, len);
	81	memcpy(buf1, buf2, len);
	82	memcpy(buf2, &swap, len);
	83	}
	84
e29d1b70 JA	85	static void hexdump(void *buffer, int len)
	86	{
	87	unsigned char *p = buffer;
	88	int i;
	89
	90	for (i = 0; i < len; i++)
6d86144d JA	91	log_info("%02x", p[i]);
6d86144d JA	92	log_info("\n");
e29d1b70 JA	93	}
e29d1b70 JA	94
d9f2caf3 JA	95	/*
	96	* Return data area 'header_num'
	97	*/
	98	static inline void io_u_verify_off(struct verify_header hdr,
	99	struct io_u *io_u,
	100	unsigned char header_num)
	101	{
	102	return io_u->buf + sizeof(hdr) + header_num hdr->len;
	103	}
	104
3f9f4e26 SL	105	static int verify_io_u_crc7(struct verify_header hdr, struct io_u io_u,
3f9f4e26 SL	106	unsigned char header_num)
1e154bdb	107	{
d9f2caf3	108	void *p = io_u_verify_off(hdr, io_u, header_num);
1e154bdb JA	109	unsigned char c;
1e154bdb JA	110
1e154bdb JA	111	c = crc7(p, hdr->len - sizeof(*hdr));
	112
	113	if (c != hdr->crc7) {
3f9f4e26 SL	114	log_err("crc7: verify failed at %llu/%u\n",
	115	io_u->offset + header_num * hdr->len,
	116	hdr->len);
1e154bdb JA	117	log_err("crc7: wanted %x, got %x\n", hdr->crc7, c);
	118	return 1;
	119	}
	120
	121	return 0;
	122	}
	123
3f9f4e26 SL	124	static int verify_io_u_crc16(struct verify_header hdr, struct io_u io_u,
3f9f4e26 SL	125	unsigned int header_num)
969f7ed3	126	{
d9f2caf3	127	void *p = io_u_verify_off(hdr, io_u, header_num);
969f7ed3 JA	128	unsigned short c;
969f7ed3 JA	129
969f7ed3 JA	130	c = crc16(p, hdr->len - sizeof(*hdr));
	131
	132	if (c != hdr->crc16) {
3f9f4e26 SL	133	log_err("crc16: verify failed at %llu/%u\n",
	134	io_u->offset + header_num * hdr->len,
	135	hdr->len);
1f24ea44	136	log_err("crc16: wanted %x, got %x\n", hdr->crc16, c);
969f7ed3 JA	137	return 1;
	138	}
	139
	140	return 0;
	141	}
	142
3f9f4e26 SL	143	static int verify_io_u_crc64(struct verify_header hdr, struct io_u io_u,
3f9f4e26 SL	144	unsigned int header_num)
d77a7af3	145	{
d9f2caf3	146	void *p = io_u_verify_off(hdr, io_u, header_num);
d77a7af3 JA	147	unsigned long long c;
	148
	149	c = crc64(p, hdr->len - sizeof(*hdr));
	150
	151	if (c != hdr->crc64) {
3f9f4e26 SL	152	log_err("crc64: verify failed at %llu/%u\n",
	153	io_u->offset + header_num * hdr->len,
	154	hdr->len);
d77a7af3 JA	155	log_err("crc64: wanted %llx, got %llx\n", hdr->crc64, c);
	156	return 1;
	157	}
	158
	159	return 0;
	160	}
	161
3f9f4e26 SL	162	static int verify_io_u_crc32(struct verify_header hdr, struct io_u io_u,
3f9f4e26 SL	163	unsigned int header_num)
e29d1b70	164	{
d9f2caf3	165	void *p = io_u_verify_off(hdr, io_u, header_num);
e29d1b70 JA	166	unsigned long c;
e29d1b70 JA	167
e29d1b70 JA	168	c = crc32(p, hdr->len - sizeof(*hdr));
	169
	170	if (c != hdr->crc32) {
3f9f4e26 SL	171	log_err("crc32: verify failed at %llu/%u\n",
	172	io_u->offset + header_num * hdr->len,
	173	hdr->len);
e29d1b70 JA	174	log_err("crc32: wanted %lx, got %lx\n", hdr->crc32, c);
	175	return 1;
	176	}
	177
	178	return 0;
	179	}
	180
3f9f4e26 SL	181	static int verify_io_u_md5(struct verify_header hdr, struct io_u io_u,
3f9f4e26 SL	182	unsigned int header_num)
e29d1b70	183	{
d9f2caf3	184	void *p = io_u_verify_off(hdr, io_u, header_num);
8c432325 JA	185	uint32_t hash[MD5_HASH_WORDS];
	186	struct md5_ctx md5_ctx = {
	187	.hash = hash,
	188	};
e29d1b70	189
fd00954c	190	memset(md5_ctx.hash, 0, sizeof(hdr->md5_digest));
e29d1b70 JA	191	md5_update(&md5_ctx, p, hdr->len - sizeof(*hdr));
e29d1b70 JA	192
c9b3fdf3	193	if (memcmp(hdr->md5_digest, md5_ctx.hash, sizeof(hash))) {
3f9f4e26 SL	194	log_err("md5: verify failed at %llu/%u\n",
	195	io_u->offset + header_num * hdr->len,
	196	hdr->len);
e29d1b70	197	hexdump(hdr->md5_digest, sizeof(hdr->md5_digest));
8c432325	198	hexdump(md5_ctx.hash, sizeof(hash));
e29d1b70 JA	199	return 1;
	200	}
	201
	202	return 0;
	203	}
	204
36690c9b	205	int verify_io_u(struct thread_data td, struct io_u io_u)
e29d1b70	206	{
3f9f4e26 SL	207	struct verify_header *hdr;
3f9f4e26 SL	208	unsigned int hdr_inc, hdr_num = 0;
95646108	209	void *p;
e29d1b70 JA	210	int ret;
e29d1b70 JA	211
1dcc0498	212	if (td->o.verify == VERIFY_NULL \|\| io_u->ddir != DDIR_READ)
36690c9b JA	213	return 0;
36690c9b JA	214
3f9f4e26	215	hdr_inc = io_u->buflen;
a59e170d JA	216	if (td->o.verify_interval)
a59e170d JA	217	hdr_inc = td->o.verify_interval;
e29d1b70	218
95646108	219	for (p = io_u->buf; p < io_u->buf + io_u->buflen; p += hdr_inc) {
a59e170d JA	220	if (td->o.verify_offset)
a59e170d JA	221	memswp(p, p + td->o.verify_offset, sizeof(*hdr));
546a9142	222
95646108	223	hdr = p;
e29d1b70	224
3f9f4e26 SL	225	if (hdr->fio_magic != FIO_HDR_MAGIC) {
	226	log_err("Bad verify header %x\n", hdr->fio_magic);
	227	return EIO;
	228	}
	229
	230	switch (hdr->verify_type) {
	231	case VERIFY_MD5:
	232	ret = verify_io_u_md5(hdr, io_u, hdr_num);
	233	break;
	234	case VERIFY_CRC64:
	235	ret = verify_io_u_crc64(hdr, io_u, hdr_num);
	236	break;
	237	case VERIFY_CRC32:
	238	ret = verify_io_u_crc32(hdr, io_u, hdr_num);
	239	break;
	240	case VERIFY_CRC16:
	241	ret = verify_io_u_crc16(hdr, io_u, hdr_num);
	242	break;
	243	case VERIFY_CRC7:
	244	ret = verify_io_u_crc7(hdr, io_u, hdr_num);
	245	break;
	246	default:
	247	log_err("Bad verify type %u\n", hdr->verify_type);
	248	ret = 1;
	249	}
	250	hdr_num++;
	251	}
a7dfe862 JA	252
a7dfe862 JA	253	return 0;
e29d1b70 JA	254	}
e29d1b70 JA	255
1e154bdb JA	256	static void fill_crc7(struct verify_header hdr, void p, unsigned int len)
	257	{
	258	hdr->crc7 = crc7(p, len);
	259	}
	260
969f7ed3 JA	261	static void fill_crc16(struct verify_header hdr, void p, unsigned int len)
	262	{
	263	hdr->crc16 = crc16(p, len);
	264	}
	265
e29d1b70 JA	266	static void fill_crc32(struct verify_header hdr, void p, unsigned int len)
	267	{
	268	hdr->crc32 = crc32(p, len);
	269	}
	270
d77a7af3 JA	271	static void fill_crc64(struct verify_header hdr, void p, unsigned int len)
	272	{
	273	hdr->crc64 = crc64(p, len);
	274	}
	275
e29d1b70 JA	276	static void fill_md5(struct verify_header hdr, void p, unsigned int len)
e29d1b70 JA	277	{
8c432325 JA	278	struct md5_ctx md5_ctx = {
	279	.hash = (uint32_t *) hdr->md5_digest,
	280	};
e29d1b70	281
fd00954c	282	memset(md5_ctx.hash, 0, sizeof(hdr->md5_digest));
e29d1b70	283	md5_update(&md5_ctx, p, len);
e29d1b70 JA	284	}
	285
	286	/*
	287	* fill body of io_u->buf with random data and add a header with the
	288	* crc32 or md5 sum of that data.
	289	*/
	290	void populate_verify_io_u(struct thread_data td, struct io_u io_u)
	291	{
baefa9be	292	struct verify_header *hdr;
95646108	293	void p = io_u->buf, data;
546a9142	294	unsigned int hdr_inc, data_len;
e29d1b70	295
9cc3d150 JA	296	if (td->o.verify == VERIFY_NULL)
	297	return;
	298
90059d65	299	fill_pattern(td, p, io_u->buflen);
546a9142 SL	300
546a9142 SL	301	hdr_inc = io_u->buflen;
a59e170d JA	302	if (td->o.verify_interval)
a59e170d JA	303	hdr_inc = td->o.verify_interval;
546a9142	304	data_len = hdr_inc - sizeof(*hdr);
baefa9be	305
95646108 JA	306	for (;p < io_u->buf + io_u->buflen; p += hdr_inc) {
95646108 JA	307	hdr = p;
3f9f4e26 SL	308
	309	hdr->fio_magic = FIO_HDR_MAGIC;
	310	hdr->verify_type = td->o.verify;
546a9142	311	hdr->len = hdr_inc;
3f9f4e26 SL	312
3f9f4e26 SL	313	data = p + sizeof(*hdr);
3f9f4e26 SL	314	switch (td->o.verify) {
	315	case VERIFY_MD5:
	316	fill_md5(hdr, data, data_len);
	317	break;
	318	case VERIFY_CRC64:
	319	fill_crc64(hdr, data, data_len);
	320	break;
	321	case VERIFY_CRC32:
	322	fill_crc32(hdr, data, data_len);
	323	break;
	324	case VERIFY_CRC16:
	325	fill_crc16(hdr, data, data_len);
	326	break;
	327	case VERIFY_CRC7:
	328	fill_crc7(hdr, data, data_len);
	329	break;
	330	default:
	331	log_err("fio: bad verify type: %d\n", td->o.verify);
	332	assert(0);
	333	}
a59e170d JA	334	if (td->o.verify_offset)
a59e170d JA	335	memswp(p, p + td->o.verify_offset, sizeof(*hdr));
e29d1b70	336	}
e29d1b70 JA	337	}
	338
	339	int get_next_verify(struct thread_data td, struct io_u io_u)
	340	{
8de8f047	341	struct io_piece *ipo = NULL;
e29d1b70	342
d2d7fa53 JA	343	/*
	344	* this io_u is from a requeue, we already filled the offsets
	345	*/
	346	if (io_u->file)
	347	return 0;
	348
8de8f047 JA	349	if (!RB_EMPTY_ROOT(&td->io_hist_tree)) {
8de8f047 JA	350	struct rb_node *n = rb_first(&td->io_hist_tree);
e29d1b70	351
8de8f047	352	ipo = rb_entry(n, struct io_piece, rb_node);
4b87898e	353	rb_erase(n, &td->io_hist_tree);
8de8f047 JA	354	} else if (!list_empty(&td->io_hist_list)) {
	355	ipo = list_entry(td->io_hist_list.next, struct io_piece, list);
	356	list_del(&ipo->list);
	357	}
e29d1b70	358
8de8f047	359	if (ipo) {
e29d1b70 JA	360	io_u->offset = ipo->offset;
e29d1b70 JA	361	io_u->buflen = ipo->len;
36167d82	362	io_u->file = ipo->file;
97af62ce JA	363
	364	if ((io_u->file->flags & FIO_FILE_OPEN) == 0) {
	365	int r = td_io_open_file(td, io_u->file);
	366
	367	if (r)
	368	return 1;
	369	}
	370
	371	get_file(ipo->file);
	372	assert(io_u->file->flags & FIO_FILE_OPEN);
e29d1b70	373	io_u->ddir = DDIR_READ;
36167d82 JA	374	io_u->xfer_buf = io_u->buf;
36167d82 JA	375	io_u->xfer_buflen = io_u->buflen;
e29d1b70 JA	376	free(ipo);
	377	return 0;
	378	}
	379
	380	return 1;
	381	}