struct lttng_ht *metadata_ht;
struct lttng_ht *data_ht;
+/*
+ * Notify a thread pipe to poll back again. This usually means that some global
+ * state has changed so we just send back the thread in a poll wait call.
+ */
+static void notify_thread_pipe(int wpipe)
+{
+ int ret;
+
+ do {
+ struct lttng_consumer_stream *null_stream = NULL;
+
+ ret = write(wpipe, &null_stream, sizeof(null_stream));
+ } while (ret < 0 && errno == EINTR);
+}
+
/*
* Find a stream. The consumer_data.lock must be locked during this
* call.
struct consumer_relayd_sock_pair *relayd =
caa_container_of(node, struct consumer_relayd_sock_pair, node);
+ /*
+ * Close all sockets. This is done in the call RCU since we don't want the
+ * socket fds to be reassigned thus potentially creating bad state of the
+ * relayd object.
+ *
+ * We do not have to lock the control socket mutex here since at this stage
+ * there is no one referencing to this relayd object.
+ */
+ (void) relayd_close(&relayd->control_sock);
+ (void) relayd_close(&relayd->data_sock);
+
free(relayd);
}
iter.iter.node = &relayd->node.node;
ret = lttng_ht_del(consumer_data.relayd_ht, &iter);
if (ret != 0) {
- /* We assume the relayd was already destroyed */
+ /* We assume the relayd is being or is destroyed */
return;
}
- /* Close all sockets */
- pthread_mutex_lock(&relayd->ctrl_sock_mutex);
- (void) relayd_close(&relayd->control_sock);
- pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
- (void) relayd_close(&relayd->data_sock);
-
/* RCU free() call */
call_rcu(&relayd->node.head, consumer_rcu_free_relayd);
}
+/*
+ * Update the end point status of all streams having the given network sequence
+ * index (relayd index).
+ *
+ * It's atomically set without having the stream mutex locked which is fine
+ * because we handle the write/read race with a pipe wakeup for each thread.
+ */
+static void update_endpoint_status_by_netidx(int net_seq_idx,
+ enum consumer_endpoint_status status)
+{
+ struct lttng_ht_iter iter;
+ struct lttng_consumer_stream *stream;
+
+ DBG("Consumer set delete flag on stream by idx %d", net_seq_idx);
+
+ rcu_read_lock();
+
+ /* Let's begin with metadata */
+ cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream, node.node) {
+ if (stream->net_seq_idx == net_seq_idx) {
+ uatomic_set(&stream->endpoint_status, status);
+ DBG("Delete flag set to metadata stream %d", stream->wait_fd);
+ }
+ }
+
+ /* Follow up by the data streams */
+ cds_lfht_for_each_entry(data_ht->ht, &iter.iter, stream, node.node) {
+ if (stream->net_seq_idx == net_seq_idx) {
+ uatomic_set(&stream->endpoint_status, status);
+ DBG("Delete flag set to data stream %d", stream->wait_fd);
+ }
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Cleanup a relayd object by flagging every associated streams for deletion,
+ * destroying the object meaning removing it from the relayd hash table,
+ * closing the sockets and freeing the memory in a RCU call.
+ *
+ * If a local data context is available, notify the threads that the streams'
+ * state have changed.
+ */
+static void cleanup_relayd(struct consumer_relayd_sock_pair *relayd,
+ struct lttng_consumer_local_data *ctx)
+{
+ int netidx;
+
+ assert(relayd);
+
+ /* Save the net sequence index before destroying the object */
+ netidx = relayd->net_seq_idx;
+
+ /*
+ * Delete the relayd from the relayd hash table, close the sockets and free
+ * the object in a RCU call.
+ */
+ destroy_relayd(relayd);
+
+ /* Set inactive endpoint to all streams */
+ update_endpoint_status_by_netidx(netidx, CONSUMER_ENDPOINT_INACTIVE);
+
+ /*
+ * With a local data context, notify the threads that the streams' state
+ * have changed. The write() action on the pipe acts as an "implicit"
+ * memory barrier ordering the updates of the end point status from the
+ * read of this status which happens AFTER receiving this notify.
+ */
+ if (ctx) {
+ notify_thread_pipe(ctx->consumer_data_pipe[1]);
+ notify_thread_pipe(ctx->consumer_metadata_pipe[1]);
+ }
+}
+
/*
* Flag a relayd socket pair for destruction. Destroy it if the refcount
* reaches zero.
assert(stream);
+ DBG("Consumer del stream %d", stream->wait_fd);
+
if (ht == NULL) {
/* Means the stream was allocated but not successfully added */
goto free_stream;
}
+ pthread_mutex_lock(&stream->lock);
pthread_mutex_lock(&consumer_data.lock);
switch (consumer_data.type) {
end:
consumer_data.need_update = 1;
pthread_mutex_unlock(&consumer_data.lock);
+ pthread_mutex_unlock(&stream->lock);
if (free_chan) {
consumer_del_channel(free_chan);
DBG("Updating poll fd array");
rcu_read_lock();
cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) {
- if (stream->state != LTTNG_CONSUMER_ACTIVE_STREAM) {
+ /*
+ * Only active streams with an active end point can be added to the
+ * poll set and local stream storage of the thread.
+ *
+ * There is a potential race here for endpoint_status to be updated
+ * just after the check. However, this is OK since the stream(s) will
+ * be deleted once the thread is notified that the end point state has
+ * changed where this function will be called back again.
+ */
+ if (stream->state != LTTNG_CONSUMER_ACTIVE_STREAM ||
+ stream->endpoint_status) {
continue;
}
DBG("Active FD %d", stream->wait_fd);
if (ret < 0) {
PERROR("write consumer quit");
}
+
+ DBG("Consumer flag that it should quit");
}
void lttng_consumer_sync_trace_file(struct lttng_consumer_stream *stream,
{
int ret;
+ DBG("Consumer destroying it. Closing everything.");
+
ret = close(ctx->consumer_error_socket);
if (ret) {
PERROR("close");
/* Default is on the disk */
int outfd = stream->out_fd;
struct consumer_relayd_sock_pair *relayd = NULL;
+ unsigned int relayd_hang_up = 0;
/* RCU lock for the relayd pointer */
rcu_read_lock();
ret = write_relayd_metadata_id(outfd, stream, relayd, padding);
if (ret < 0) {
written = ret;
+ /* Socket operation failed. We consider the relayd dead */
+ if (ret == -EPIPE || ret == -EINVAL) {
+ relayd_hang_up = 1;
+ goto write_error;
+ }
goto end;
}
}
+ } else {
+ /* Socket operation failed. We consider the relayd dead */
+ if (ret == -EPIPE || ret == -EINVAL) {
+ relayd_hang_up = 1;
+ goto write_error;
+ }
+ /* Else, use the default set before which is the filesystem. */
}
- /* Else, use the default set before which is the filesystem. */
} else {
/* No streaming, we have to set the len with the full padding */
len += padding;
if (written == 0) {
written = ret;
}
+ /* Socket operation failed. We consider the relayd dead */
+ if (errno == EPIPE || errno == EINVAL) {
+ relayd_hang_up = 1;
+ goto write_error;
+ }
goto end;
} else if (ret > len) {
PERROR("Error in file write (ret %zd > len %lu)", ret, len);
}
lttng_consumer_sync_trace_file(stream, orig_offset);
+write_error:
+ /*
+ * This is a special case that the relayd has closed its socket. Let's
+ * cleanup the relayd object and all associated streams.
+ */
+ if (relayd && relayd_hang_up) {
+ cleanup_relayd(relayd, ctx);
+ }
+
end:
- pthread_mutex_unlock(&stream->lock);
/* Unlock only if ctrl socket used */
if (relayd && stream->metadata_flag) {
pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
}
+ pthread_mutex_unlock(&stream->lock);
rcu_read_unlock();
return written;
int outfd = stream->out_fd;
struct consumer_relayd_sock_pair *relayd = NULL;
int *splice_pipe;
+ unsigned int relayd_hang_up = 0;
switch (consumer_data.type) {
case LTTNG_CONSUMER_KERNEL:
padding);
if (ret < 0) {
written = ret;
+ /* Socket operation failed. We consider the relayd dead */
+ if (ret == -EBADF) {
+ WARN("Remote relayd disconnected. Stopping");
+ relayd_hang_up = 1;
+ goto write_error;
+ }
goto end;
}
/* Use the returned socket. */
outfd = ret;
} else {
- ERR("Remote relayd disconnected. Stopping");
+ /* Socket operation failed. We consider the relayd dead */
+ if (ret == -EBADF) {
+ WARN("Remote relayd disconnected. Stopping");
+ relayd_hang_up = 1;
+ goto write_error;
+ }
goto end;
}
} else {
if (written == 0) {
written = ret_splice;
}
+ /* Socket operation failed. We consider the relayd dead */
+ if (errno == EBADF) {
+ WARN("Remote relayd disconnected. Stopping");
+ relayd_hang_up = 1;
+ goto write_error;
+ }
ret = errno;
goto splice_error;
} else if (ret_splice > len) {
goto end;
+write_error:
+ /*
+ * This is a special case that the relayd has closed its socket. Let's
+ * cleanup the relayd object and all associated streams.
+ */
+ if (relayd && relayd_hang_up) {
+ cleanup_relayd(relayd, ctx);
+ /* Skip splice error so the consumer does not fail */
+ goto end;
+ }
+
splice_error:
/* send the appropriate error description to sessiond */
switch (ret) {
- case EBADF:
- lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_EBADF);
- break;
case EINVAL:
lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_EINVAL);
break;
}
end:
- pthread_mutex_unlock(&stream->lock);
if (relayd && stream->metadata_flag) {
pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
}
+ pthread_mutex_unlock(&stream->lock);
rcu_read_unlock();
return written;
goto free_stream;
}
+ pthread_mutex_lock(&stream->lock);
+
pthread_mutex_lock(&consumer_data.lock);
switch (consumer_data.type) {
case LTTNG_CONSUMER_KERNEL:
end:
pthread_mutex_unlock(&consumer_data.lock);
+ pthread_mutex_unlock(&stream->lock);
if (free_chan) {
consumer_del_channel(free_chan);
return ret;
}
+/*
+ * Delete data stream that are flagged for deletion (endpoint_status).
+ */
+static void validate_endpoint_status_data_stream(void)
+{
+ struct lttng_ht_iter iter;
+ struct lttng_consumer_stream *stream;
+
+ DBG("Consumer delete flagged data stream");
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(data_ht->ht, &iter.iter, stream, node.node) {
+ /* Validate delete flag of the stream */
+ if (!stream->endpoint_status) {
+ continue;
+ }
+ /* Delete it right now */
+ consumer_del_stream(stream, data_ht);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Delete metadata stream that are flagged for deletion (endpoint_status).
+ */
+static void validate_endpoint_status_metadata_stream(
+ struct lttng_poll_event *pollset)
+{
+ struct lttng_ht_iter iter;
+ struct lttng_consumer_stream *stream;
+
+ DBG("Consumer delete flagged metadata stream");
+
+ assert(pollset);
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream, node.node) {
+ /* Validate delete flag of the stream */
+ if (!stream->endpoint_status) {
+ continue;
+ }
+ /*
+ * Remove from pollset so the metadata thread can continue without
+ * blocking on a deleted stream.
+ */
+ lttng_poll_del(pollset, stream->wait_fd);
+
+ /* Delete it right now */
+ consumer_del_metadata_stream(stream, metadata_ht);
+ }
+ rcu_read_unlock();
+}
+
/*
* Thread polls on metadata file descriptor and write them on disk or on the
* network.
continue;
}
+ /* A NULL stream means that the state has changed. */
+ if (stream == NULL) {
+ /* Check for deleted streams. */
+ validate_endpoint_status_metadata_stream(&events);
+ continue;
+ }
+
DBG("Adding metadata stream %d to poll set",
stream->wait_fd);
len = ctx->on_buffer_ready(stream, ctx);
/* It's ok to have an unavailable sub-buffer */
if (len < 0 && len != -EAGAIN && len != -ENODATA) {
- rcu_read_unlock();
- goto end;
+ /* Clean up stream from consumer and free it. */
+ lttng_poll_del(&events, stream->wait_fd);
+ consumer_del_metadata_stream(stream, metadata_ht);
} else if (len > 0) {
stream->data_read = 1;
}
* waking us up to test it.
*/
if (new_stream == NULL) {
+ validate_endpoint_status_data_stream();
continue;
}
len = ctx->on_buffer_ready(local_stream[i], ctx);
/* it's ok to have an unavailable sub-buffer */
if (len < 0 && len != -EAGAIN && len != -ENODATA) {
- goto end;
+ /* Clean the stream and free it. */
+ consumer_del_stream(local_stream[i], data_ht);
} else if (len > 0) {
local_stream[i]->data_read = 1;
}
len = ctx->on_buffer_ready(local_stream[i], ctx);
/* it's ok to have an unavailable sub-buffer */
if (len < 0 && len != -EAGAIN && len != -ENODATA) {
- goto end;
+ /* Clean the stream and free it. */
+ consumer_del_stream(local_stream[i], data_ht);
} else if (len > 0) {
local_stream[i]->data_read = 1;
}
/*
* Notify the data poll thread to poll back again and test the
- * consumer_quit state to quit gracefully.
+ * consumer_quit state that we just set so to quit gracefully.
*/
- do {
- struct lttng_consumer_stream *null_stream = NULL;
-
- ret = write(ctx->consumer_data_pipe[1], &null_stream,
- sizeof(null_stream));
- } while (ret < 0 && errno == EINTR);
+ notify_thread_pipe(ctx->consumer_data_pipe[1]);
rcu_unregister_thread();
return NULL;
return ret;
}
+/*
+ * Try to lock the stream mutex.
+ *
+ * On success, 1 is returned else 0 indicating that the mutex is NOT lock.
+ */
+static int stream_try_lock(struct lttng_consumer_stream *stream)
+{
+ int ret;
+
+ assert(stream);
+
+ /*
+ * Try to lock the stream mutex. On failure, we know that the stream is
+ * being used else where hence there is data still being extracted.
+ */
+ ret = pthread_mutex_trylock(&stream->lock);
+ if (ret) {
+ /* For both EBUSY and EINVAL error, the mutex is NOT locked. */
+ ret = 0;
+ goto end;
+ }
+
+ ret = 1;
+
+end:
+ return ret;
+}
+
/*
* Check if for a given session id there is still data needed to be extract
* from the buffers.
DBG("Consumer data available command on session id %" PRIu64, id);
+ rcu_read_lock();
pthread_mutex_lock(&consumer_data.lock);
switch (consumer_data.type) {
assert(0);
}
- rcu_read_lock();
-
/* Ease our life a bit */
ht = consumer_data.stream_list_ht;
ht->hash_fct((void *)((unsigned long) id), 0x42UL),
ht->match_fct, (void *)((unsigned long) id),
&iter.iter, stream, node_session_id.node) {
- /* Check the stream for data. */
- ret = data_available(stream);
- if (ret == 0) {
+ /* If this call fails, the stream is being used hence data pending. */
+ ret = stream_try_lock(stream);
+ if (!ret) {
goto data_not_available;
}
+ /*
+ * A removed node from the hash table indicates that the stream has
+ * been deleted thus having a guarantee that the buffers are closed
+ * on the consumer side. However, data can still be transmitted
+ * over the network so don't skip the relayd check.
+ */
+ ret = cds_lfht_is_node_deleted(&stream->node.node);
+ if (!ret) {
+ /* Check the stream if there is data in the buffers. */
+ ret = data_available(stream);
+ if (ret == 0) {
+ pthread_mutex_unlock(&stream->lock);
+ goto data_not_available;
+ }
+ }
+
+ /* Relayd check */
if (stream->net_seq_idx != -1) {
relayd = consumer_find_relayd(stream->net_seq_idx);
- assert(relayd);
+ if (!relayd) {
+ /*
+ * At this point, if the relayd object is not available for the
+ * given stream, it is because the relayd is being cleaned up
+ * so every stream associated with it (for a session id value)
+ * are or will be marked for deletion hence no data pending.
+ */
+ pthread_mutex_unlock(&stream->lock);
+ goto data_not_available;
+ }
- pthread_mutex_lock(&stream->lock);
pthread_mutex_lock(&relayd->ctrl_sock_mutex);
if (stream->metadata_flag) {
ret = relayd_quiescent_control(&relayd->control_sock);
stream->relayd_stream_id, stream->next_net_seq_num);
}
pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
- pthread_mutex_unlock(&stream->lock);
if (ret == 0) {
+ pthread_mutex_unlock(&stream->lock);
goto data_not_available;
}
}
+ pthread_mutex_unlock(&stream->lock);
}
/*
projects / lttng-tools.git / blobdiff