[lttng-tools.git] / src / bin / lttng-relayd / index.c

/*
 * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
 *                      David Goulet <dgoulet@efficios.com>
 *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License, version 2 only, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _LGPL_SOURCE
#include <assert.h>

#include <common/common.h>
#include <common/utils.h>

#include "lttng-relayd.h"
#include "stream.h"
#include "index.h"

/*
 * Allocate a new relay index object. Pass the stream in which it is
 * contained as parameter. The sequence number will be used as the hash
 * table key.
 *
 * Called with stream mutex held.
 * Return allocated object or else NULL on error.
 */
static struct relay_index *relay_index_create(struct relay_stream *stream,
		uint64_t net_seq_num)
{
	struct relay_index *index;

	DBG2("Creating relay index for stream id %" PRIu64 " and seqnum %" PRIu64,
			stream->stream_handle, net_seq_num);

	index = zmalloc(sizeof(*index));
	if (!index) {
		PERROR("Relay index zmalloc");
		goto end;
	}
	if (!stream_get(stream)) {
		ERR("Cannot get stream");
		free(index);
		index = NULL;
		goto end;
	}
	index->stream = stream;

	lttng_ht_node_init_u64(&index->index_n, net_seq_num);
	pthread_mutex_init(&index->lock, NULL);
	urcu_ref_init(&index->ref);

end:
	return index;
}

/*
 * Add unique relay index to the given hash table. In case of a collision, the
 * already existing object is put in the given _index variable.
 *
 * RCU read side lock MUST be acquired.
 */
static struct relay_index *relay_index_add_unique(struct relay_stream *stream,
		struct relay_index *index)
{
	struct cds_lfht_node *node_ptr;
	struct relay_index *_index;

	DBG2("Adding relay index with stream id %" PRIu64 " and seqnum %" PRIu64,
			stream->stream_handle, index->index_n.key);

	node_ptr = cds_lfht_add_unique(stream->indexes_ht->ht,
			stream->indexes_ht->hash_fct(&index->index_n, lttng_ht_seed),
			stream->indexes_ht->match_fct, &index->index_n,
			&index->index_n.node);
	if (node_ptr != &index->index_n.node) {
		_index = caa_container_of(node_ptr, struct relay_index,
				index_n.node);
	} else {
		_index = NULL;
	}
	return _index;
}

/*
 * Should be called with RCU read-side lock held.
 */
static bool relay_index_get(struct relay_index *index)
{
	DBG2("index get for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
			index->stream->stream_handle, index->index_n.key,
			(int) index->ref.refcount);

	return urcu_ref_get_unless_zero(&index->ref);
}

/*
 * Get a relayd index in within the given stream, or create it if not
 * present.
 *
 * Called with stream mutex held.
 * Return index object or else NULL on error.
 */
struct relay_index *relay_index_get_by_id_or_create(struct relay_stream *stream,
		 uint64_t net_seq_num)
{
	struct lttng_ht_node_u64 *node;
	struct lttng_ht_iter iter;
	struct relay_index *index = NULL;

	DBG3("Finding index for stream id %" PRIu64 " and seq_num %" PRIu64,
			stream->stream_handle, net_seq_num);

	rcu_read_lock();
	lttng_ht_lookup(stream->indexes_ht, &net_seq_num, &iter);
	node = lttng_ht_iter_get_node_u64(&iter);
	if (node) {
		index = caa_container_of(node, struct relay_index, index_n);
	} else {
		struct relay_index *oldindex;

		index = relay_index_create(stream, net_seq_num);
		if (!index) {
			ERR("Cannot create index for stream id %" PRIu64 " and seq_num %" PRIu64,
				stream->stream_handle, net_seq_num);
			goto end;
		}
		oldindex = relay_index_add_unique(stream, index);
		if (oldindex) {
			/* Added concurrently, keep old. */
			relay_index_put(index);
			index = oldindex;
			if (!relay_index_get(index)) {
				index = NULL;
			}
		} else {
			stream->indexes_in_flight++;
			index->in_hash_table = true;
		}
	}
end:
	rcu_read_unlock();
	DBG2("Index %sfound or created in HT for stream ID %" PRIu64 " and seqnum %" PRIu64,
			(index == NULL) ? "NOT " : "", stream->stream_handle, net_seq_num);
	return index;
}

int relay_index_set_file(struct relay_index *index,
		struct lttng_index_file *index_file,
		uint64_t data_offset)
{
	int ret = 0;

	pthread_mutex_lock(&index->lock);
	if (index->index_file) {
		ret = -1;
		goto end;
	}
	lttng_index_file_get(index_file);
	index->index_file = index_file;
	index->index_data.offset = data_offset;
end:
	pthread_mutex_unlock(&index->lock);
	return ret;
}

int relay_index_set_data(struct relay_index *index,
                const struct ctf_packet_index *data)
{
	int ret = 0;

	pthread_mutex_lock(&index->lock);
	if (index->has_index_data) {
		ret = -1;
		goto end;
	}
	/* Set everything except data_offset. */
	index->index_data.packet_size = data->packet_size;
	index->index_data.content_size = data->content_size;
	index->index_data.timestamp_begin = data->timestamp_begin;
	index->index_data.timestamp_end = data->timestamp_end;
	index->index_data.events_discarded = data->events_discarded;
	index->index_data.stream_id = data->stream_id;
	index->has_index_data = true;
end:
	pthread_mutex_unlock(&index->lock);
	return ret;
}

static void index_destroy(struct relay_index *index)
{
	free(index);
}

static void index_destroy_rcu(struct rcu_head *rcu_head)
{
	struct relay_index *index =
		caa_container_of(rcu_head, struct relay_index, rcu_node);

	index_destroy(index);
}

/* Stream lock must be held by the caller. */
static void index_release(struct urcu_ref *ref)
{
	struct relay_index *index = caa_container_of(ref, struct relay_index, ref);
	struct relay_stream *stream = index->stream;
	int ret;
	struct lttng_ht_iter iter;

	if (index->index_file) {
		lttng_index_file_put(index->index_file);
		index->index_file = NULL;
	}
	if (index->in_hash_table) {
		/* Delete index from hash table. */
		iter.iter.node = &index->index_n.node;
		ret = lttng_ht_del(stream->indexes_ht, &iter);
		assert(!ret);
		stream->indexes_in_flight--;
	}

	stream_put(index->stream);
	index->stream = NULL;

	call_rcu(&index->rcu_node, index_destroy_rcu);
}

/*
 * Called with stream mutex held.
 *
 * Stream lock must be held by the caller.
 */
void relay_index_put(struct relay_index *index)
{
	DBG2("index put for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
			index->stream->stream_handle, index->index_n.key,
			(int) index->ref.refcount);
	/*
	 * Ensure existance of index->lock for index unlock.
	 */
	rcu_read_lock();
	/*
	 * Index lock ensures that concurrent test and update of stream
	 * ref is atomic.
	 */
	assert(index->ref.refcount != 0);
	urcu_ref_put(&index->ref, index_release);
	rcu_read_unlock();
}

/*
 * Try to flush index to disk. Releases self-reference to index once
 * flush succeeds.
 *
 * Stream lock must be held by the caller.
 * Return 0 on successful flush, a negative value on error, or positive
 * value if no flush was performed.
 */
int relay_index_try_flush(struct relay_index *index)
{
	int ret = 1;
	bool flushed = false;
	int fd;

	pthread_mutex_lock(&index->lock);
	if (index->flushed) {
		goto skip;
	}
	/* Check if we are ready to flush. */
	if (!index->has_index_data || !index->index_file) {
		goto skip;
	}
	fd = index->index_file->fd;
	DBG2("Writing index for stream ID %" PRIu64 " and seq num %" PRIu64
			" on fd %d", index->stream->stream_handle,
			index->index_n.key, fd);
	flushed = true;
	index->flushed = true;
	ret = lttng_index_file_write(index->index_file, &index->index_data);
skip:
	pthread_mutex_unlock(&index->lock);

	if (flushed) {
		/* Put self-ref from index now that it has been flushed. */
		relay_index_put(index);
	}
	return ret;
}

/*
 * Close every relay index within a given stream, without flushing
 * them.
 */
void relay_index_close_all(struct relay_stream *stream)
{
	struct lttng_ht_iter iter;
	struct relay_index *index;

	rcu_read_lock();
	cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
			index, index_n.node) {
		/* Put self-ref from index. */
		relay_index_put(index);
	}
	rcu_read_unlock();
}

void relay_index_close_partial_fd(struct relay_stream *stream)
{
	struct lttng_ht_iter iter;
	struct relay_index *index;

	rcu_read_lock();
	cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
			index, index_n.node) {
		if (!index->index_file) {
			continue;
		}
		/*
		 * Partial index has its index_file: we have only
		 * received its info from the data socket.
		 * Put self-ref from index.
		 */
		relay_index_put(index);
	}
	rcu_read_unlock();
}

uint64_t relay_index_find_last(struct relay_stream *stream)
{
	struct lttng_ht_iter iter;
	struct relay_index *index;
	uint64_t net_seq_num = -1ULL;

	rcu_read_lock();
	cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
			index, index_n.node) {
		if (net_seq_num == -1ULL ||
				index->index_n.key > net_seq_num) {
			net_seq_num = index->index_n.key;
		}
	}
	rcu_read_unlock();
	return net_seq_num;
}
Commit	Line	Data
1c20f0e2 JD	1	/*
	2	* Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
	3	* David Goulet <dgoulet@efficios.com>
7591bab1	4	* 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
1c20f0e2 JD	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License, version 2 only, as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc., 51
	17	* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	18	*/
	19
6c1c0768	20	#define _LGPL_SOURCE
1c20f0e2 JD	21	#include <assert.h>
	22
	23	#include <common/common.h>
	24	#include <common/utils.h>
	25
0a6518b0	26	#include "lttng-relayd.h"
7591bab1	27	#include "stream.h"
1c20f0e2 JD	28	#include "index.h"
	29
	30	/*
7591bab1 MD	31	* Allocate a new relay index object. Pass the stream in which it is
	32	* contained as parameter. The sequence number will be used as the hash
	33	* table key.
	34	*
	35	* Called with stream mutex held.
	36	* Return allocated object or else NULL on error.
1c20f0e2	37	*/
7591bab1 MD	38	static struct relay_index relay_index_create(struct relay_stream stream,
7591bab1 MD	39	uint64_t net_seq_num)
1c20f0e2	40	{
7591bab1	41	struct relay_index *index;
1c20f0e2	42
7591bab1 MD	43	DBG2("Creating relay index for stream id %" PRIu64 " and seqnum %" PRIu64,
7591bab1 MD	44	stream->stream_handle, net_seq_num);
1c20f0e2	45
7591bab1 MD	46	index = zmalloc(sizeof(*index));
	47	if (!index) {
	48	PERROR("Relay index zmalloc");
	49	goto end;
	50	}
	51	if (!stream_get(stream)) {
	52	ERR("Cannot get stream");
	53	free(index);
	54	index = NULL;
	55	goto end;
1c20f0e2	56	}
7591bab1	57	index->stream = stream;
1c20f0e2	58
7591bab1 MD	59	lttng_ht_node_init_u64(&index->index_n, net_seq_num);
7591bab1 MD	60	pthread_mutex_init(&index->lock, NULL);
7591bab1 MD	61	urcu_ref_init(&index->ref);
	62
	63	end:
	64	return index;
1c20f0e2 JD	65	}
	66
	67	/*
7591bab1 MD	68	* Add unique relay index to the given hash table. In case of a collision, the
7591bab1 MD	69	* already existing object is put in the given _index variable.
1c20f0e2	70	*
7591bab1	71	* RCU read side lock MUST be acquired.
1c20f0e2	72	*/
7591bab1 MD	73	static struct relay_index relay_index_add_unique(struct relay_stream stream,
7591bab1 MD	74	struct relay_index *index)
1c20f0e2	75	{
7591bab1 MD	76	struct cds_lfht_node *node_ptr;
7591bab1 MD	77	struct relay_index *_index;
1c20f0e2	78
7591bab1 MD	79	DBG2("Adding relay index with stream id %" PRIu64 " and seqnum %" PRIu64,
7591bab1 MD	80	stream->stream_handle, index->index_n.key);
1c20f0e2	81
7591bab1 MD	82	node_ptr = cds_lfht_add_unique(stream->indexes_ht->ht,
	83	stream->indexes_ht->hash_fct(&index->index_n, lttng_ht_seed),
	84	stream->indexes_ht->match_fct, &index->index_n,
	85	&index->index_n.node);
	86	if (node_ptr != &index->index_n.node) {
	87	_index = caa_container_of(node_ptr, struct relay_index,
	88	index_n.node);
	89	} else {
	90	_index = NULL;
1c20f0e2	91	}
7591bab1 MD	92	return _index;
	93	}
	94
	95	/*
	96	* Should be called with RCU read-side lock held.
	97	*/
	98	static bool relay_index_get(struct relay_index *index)
	99	{
7591bab1 MD	100	DBG2("index get for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
	101	index->stream->stream_handle, index->index_n.key,
	102	(int) index->ref.refcount);
1c20f0e2	103
ce4d4083	104	return urcu_ref_get_unless_zero(&index->ref);
1c20f0e2 JD	105	}
	106
	107	/*
7591bab1 MD	108	* Get a relayd index in within the given stream, or create it if not
7591bab1 MD	109	* present.
1c20f0e2	110	*
7591bab1	111	* Called with stream mutex held.
1c20f0e2 JD	112	* Return index object or else NULL on error.
1c20f0e2 JD	113	*/
7591bab1 MD	114	struct relay_index relay_index_get_by_id_or_create(struct relay_stream stream,
7591bab1 MD	115	uint64_t net_seq_num)
1c20f0e2	116	{
7591bab1	117	struct lttng_ht_node_u64 *node;
1c20f0e2	118	struct lttng_ht_iter iter;
1c20f0e2 JD	119	struct relay_index *index = NULL;
1c20f0e2 JD	120
1c20f0e2	121	DBG3("Finding index for stream id %" PRIu64 " and seq_num %" PRIu64,
7591bab1	122	stream->stream_handle, net_seq_num);
1c20f0e2	123
7591bab1 MD	124	rcu_read_lock();
	125	lttng_ht_lookup(stream->indexes_ht, &net_seq_num, &iter);
	126	node = lttng_ht_iter_get_node_u64(&iter);
	127	if (node) {
	128	index = caa_container_of(node, struct relay_index, index_n);
	129	} else {
	130	struct relay_index *oldindex;
	131
	132	index = relay_index_create(stream, net_seq_num);
	133	if (!index) {
	134	ERR("Cannot create index for stream id %" PRIu64 " and seq_num %" PRIu64,
811a4037	135	stream->stream_handle, net_seq_num);
7591bab1 MD	136	goto end;
	137	}
	138	oldindex = relay_index_add_unique(stream, index);
	139	if (oldindex) {
	140	/* Added concurrently, keep old. */
	141	relay_index_put(index);
	142	index = oldindex;
	143	if (!relay_index_get(index)) {
	144	index = NULL;
	145	}
	146	} else {
	147	stream->indexes_in_flight++;
	148	index->in_hash_table = true;
	149	}
1c20f0e2	150	}
1c20f0e2	151	end:
7591bab1 MD	152	rcu_read_unlock();
7591bab1 MD	153	DBG2("Index %sfound or created in HT for stream ID %" PRIu64 " and seqnum %" PRIu64,
719155c2	154	(index == NULL) ? "NOT " : "", stream->stream_handle, net_seq_num);
1c20f0e2 JD	155	return index;
	156	}
	157
f8f3885c MD	158	int relay_index_set_file(struct relay_index *index,
f8f3885c MD	159	struct lttng_index_file *index_file,
7591bab1	160	uint64_t data_offset)
1c20f0e2	161	{
7591bab1	162	int ret = 0;
1c20f0e2	163
7591bab1	164	pthread_mutex_lock(&index->lock);
f8f3885c	165	if (index->index_file) {
7591bab1 MD	166	ret = -1;
	167	goto end;
	168	}
f8f3885c MD	169	lttng_index_file_get(index_file);
f8f3885c MD	170	index->index_file = index_file;
7591bab1 MD	171	index->index_data.offset = data_offset;
	172	end:
	173	pthread_mutex_unlock(&index->lock);
	174	return ret;
	175	}
1c20f0e2	176
7591bab1 MD	177	int relay_index_set_data(struct relay_index *index,
	178	const struct ctf_packet_index *data)
	179	{
	180	int ret = 0;
1c20f0e2	181
7591bab1 MD	182	pthread_mutex_lock(&index->lock);
	183	if (index->has_index_data) {
	184	ret = -1;
	185	goto end;
1c20f0e2	186	}
7591bab1 MD	187	/* Set everything except data_offset. */
	188	index->index_data.packet_size = data->packet_size;
	189	index->index_data.content_size = data->content_size;
	190	index->index_data.timestamp_begin = data->timestamp_begin;
	191	index->index_data.timestamp_end = data->timestamp_end;
	192	index->index_data.events_discarded = data->events_discarded;
	193	index->index_data.stream_id = data->stream_id;
	194	index->has_index_data = true;
	195	end:
	196	pthread_mutex_unlock(&index->lock);
	197	return ret;
1c20f0e2 JD	198	}
1c20f0e2 JD	199
7591bab1	200	static void index_destroy(struct relay_index *index)
1c20f0e2	201	{
7591bab1 MD	202	free(index);
7591bab1 MD	203	}
1c20f0e2	204
7591bab1 MD	205	static void index_destroy_rcu(struct rcu_head *rcu_head)
	206	{
	207	struct relay_index *index =
	208	caa_container_of(rcu_head, struct relay_index, rcu_node);
1c20f0e2	209
7591bab1	210	index_destroy(index);
1c20f0e2 JD	211	}
1c20f0e2 JD	212
7591bab1 MD	213	/* Stream lock must be held by the caller. */
7591bab1 MD	214	static void index_release(struct urcu_ref *ref)
1c20f0e2	215	{
7591bab1 MD	216	struct relay_index *index = caa_container_of(ref, struct relay_index, ref);
	217	struct relay_stream *stream = index->stream;
	218	int ret;
	219	struct lttng_ht_iter iter;
	220
f8f3885c MD	221	if (index->index_file) {
	222	lttng_index_file_put(index->index_file);
	223	index->index_file = NULL;
7591bab1 MD	224	}
	225	if (index->in_hash_table) {
	226	/* Delete index from hash table. */
	227	iter.iter.node = &index->index_n.node;
	228	ret = lttng_ht_del(stream->indexes_ht, &iter);
	229	assert(!ret);
	230	stream->indexes_in_flight--;
	231	}
	232
	233	stream_put(index->stream);
	234	index->stream = NULL;
	235
	236	call_rcu(&index->rcu_node, index_destroy_rcu);
1c20f0e2 JD	237	}
	238
	239	/*
7591bab1 MD	240	* Called with stream mutex held.
	241	*
	242	* Stream lock must be held by the caller.
1c20f0e2	243	*/
7591bab1	244	void relay_index_put(struct relay_index *index)
1c20f0e2	245	{
7591bab1 MD	246	DBG2("index put for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
	247	index->stream->stream_handle, index->index_n.key,
	248	(int) index->ref.refcount);
	249	/*
	250	* Ensure existance of index->lock for index unlock.
	251	*/
	252	rcu_read_lock();
	253	/*
	254	* Index lock ensures that concurrent test and update of stream
	255	* ref is atomic.
	256	*/
7591bab1 MD	257	assert(index->ref.refcount != 0);
7591bab1 MD	258	urcu_ref_put(&index->ref, index_release);
7591bab1	259	rcu_read_unlock();
1c20f0e2 JD	260	}
	261
	262	/*
7591bab1 MD	263	* Try to flush index to disk. Releases self-reference to index once
7591bab1 MD	264	* flush succeeds.
1c20f0e2	265	*
7591bab1 MD	266	* Stream lock must be held by the caller.
	267	* Return 0 on successful flush, a negative value on error, or positive
	268	* value if no flush was performed.
1c20f0e2	269	*/
7591bab1	270	int relay_index_try_flush(struct relay_index *index)
1c20f0e2	271	{
7591bab1 MD	272	int ret = 1;
	273	bool flushed = false;
	274	int fd;
1c20f0e2	275
7591bab1 MD	276	pthread_mutex_lock(&index->lock);
	277	if (index->flushed) {
	278	goto skip;
	279	}
	280	/* Check if we are ready to flush. */
f8f3885c	281	if (!index->has_index_data \|\| !index->index_file) {
7591bab1 MD	282	goto skip;
7591bab1 MD	283	}
f8f3885c	284	fd = index->index_file->fd;
7591bab1 MD	285	DBG2("Writing index for stream ID %" PRIu64 " and seq num %" PRIu64
	286	" on fd %d", index->stream->stream_handle,
	287	index->index_n.key, fd);
	288	flushed = true;
	289	index->flushed = true;
f8f3885c	290	ret = lttng_index_file_write(index->index_file, &index->index_data);
7591bab1 MD	291	skip:
7591bab1 MD	292	pthread_mutex_unlock(&index->lock);
1c20f0e2	293
7591bab1 MD	294	if (flushed) {
	295	/* Put self-ref from index now that it has been flushed. */
	296	relay_index_put(index);
	297	}
	298	return ret;
1c20f0e2 JD	299	}
	300
	301	/*
7591bab1 MD	302	* Close every relay index within a given stream, without flushing
7591bab1 MD	303	* them.
1c20f0e2	304	*/
7591bab1	305	void relay_index_close_all(struct relay_stream *stream)
1c20f0e2 JD	306	{
	307	struct lttng_ht_iter iter;
	308	struct relay_index *index;
	309
1c20f0e2	310	rcu_read_lock();
7591bab1 MD	311	cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
	312	index, index_n.node) {
	313	/* Put self-ref from index. */
	314	relay_index_put(index);
1c20f0e2 JD	315	}
	316	rcu_read_unlock();
	317	}
3d07a857 MD	318
	319	void relay_index_close_partial_fd(struct relay_stream *stream)
	320	{
	321	struct lttng_ht_iter iter;
	322	struct relay_index *index;
	323
	324	rcu_read_lock();
	325	cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
	326	index, index_n.node) {
f8f3885c	327	if (!index->index_file) {
3d07a857 MD	328	continue;
	329	}
	330	/*
f8f3885c	331	* Partial index has its index_file: we have only
3d07a857 MD	332	* received its info from the data socket.
	333	* Put self-ref from index.
	334	*/
	335	relay_index_put(index);
	336	}
	337	rcu_read_unlock();
	338	}
	339
	340	uint64_t relay_index_find_last(struct relay_stream *stream)
	341	{
	342	struct lttng_ht_iter iter;
	343	struct relay_index *index;
	344	uint64_t net_seq_num = -1ULL;
	345
	346	rcu_read_lock();
	347	cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
	348	index, index_n.node) {
	349	if (net_seq_num == -1ULL \|\|
	350	index->index_n.key > net_seq_num) {
	351	net_seq_num = index->index_n.key;
	352	}
	353	}
	354	rcu_read_unlock();
	355	return net_seq_num;
	356	}