consumerd: cleanup: use buffer view interface for mmap read subbuf
[lttng-tools.git] / src / common / kernel-consumer / kernel-consumer.c
index b1cc03e860a0e9b10d34a5e8f528f3fcb4d90ae5..54314ec75a2c4d7758fd3c3ac2cd4d8492dee893 100644 (file)
@@ -1,21 +1,14 @@
 /*
- * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
- *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2011 Julien Desfossez <julien.desfossez@polymtl.ca>
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@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.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * 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.
  */
 
+#include "common/buffer-view.h"
+#include <stdint.h>
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <poll.h>
 #include <common/consumer/consumer-stream.h>
 #include <common/index/index.h>
 #include <common/consumer/consumer-timer.h>
+#include <common/optional.h>
 
 #include "kernel-consumer.h"
 
 extern struct lttng_consumer_global_data consumer_data;
 extern int consumer_poll_timeout;
-extern volatile int consumer_quit;
 
 /*
  * Take a snapshot for a specific fd
@@ -60,14 +53,30 @@ int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream *stream)
        int infd = stream->wait_fd;
 
        ret = kernctl_snapshot(infd);
-       if (ret != 0) {
+       /*
+        * -EAGAIN is not an error, it just means that there is no data to
+        *  be read.
+        */
+       if (ret != 0 && ret != -EAGAIN) {
                PERROR("Getting sub-buffer snapshot.");
-               ret = -errno;
        }
 
        return ret;
 }
 
+/*
+ * Sample consumed and produced positions for a specific fd.
+ *
+ * Returns 0 on success, < 0 on error.
+ */
+int lttng_kconsumer_sample_snapshot_positions(
+               struct lttng_consumer_stream *stream)
+{
+       assert(stream);
+
+       return kernctl_snapshot_sample_positions(stream->wait_fd);
+}
+
 /*
  * Get the produced position
  *
@@ -82,7 +91,6 @@ int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
        ret = kernctl_snapshot_get_produced(infd, pos);
        if (ret != 0) {
                PERROR("kernctl_snapshot_get_produced");
-               ret = -errno;
        }
 
        return ret;
@@ -102,47 +110,60 @@ int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
        ret = kernctl_snapshot_get_consumed(infd, pos);
        if (ret != 0) {
                PERROR("kernctl_snapshot_get_consumed");
-               ret = -errno;
        }
 
        return ret;
 }
 
+static
+int get_current_subbuf_addr(struct lttng_consumer_stream *stream,
+               const char **addr)
+{
+       int ret;
+       unsigned long mmap_offset;
+       const char *mmap_base = stream->mmap_base;
+
+       ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
+       if (ret < 0) {
+               PERROR("Failed to get mmap read offset");
+               goto error;
+       }
+
+       *addr = mmap_base + mmap_offset;
+error:
+       return ret;
+}
+
 /*
  * Take a snapshot of all the stream of a channel
+ * RCU read-side lock must be held across this function to ensure existence of
+ * channel. The channel lock must be held by the caller.
  *
  * Returns 0 on success, < 0 on error
  */
-int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
-               uint64_t relayd_id, uint64_t nb_packets_per_stream,
+static int lttng_kconsumer_snapshot_channel(
+               struct lttng_consumer_channel *channel,
+               uint64_t key, char *path, uint64_t relayd_id,
+               uint64_t nb_packets_per_stream,
                struct lttng_consumer_local_data *ctx)
 {
        int ret;
-       unsigned long consumed_pos, produced_pos;
-       struct lttng_consumer_channel *channel;
        struct lttng_consumer_stream *stream;
 
        DBG("Kernel consumer snapshot channel %" PRIu64, key);
 
        rcu_read_lock();
 
-       channel = consumer_find_channel(key);
-       if (!channel) {
-               ERR("No channel found for key %" PRIu64, key);
-               ret = -1;
-               goto end;
-       }
-
        /* Splice is not supported yet for channel snapshot. */
        if (channel->output != CONSUMER_CHANNEL_MMAP) {
-               ERR("Unsupported output %d", channel->output);
+               ERR("Unsupported output type for channel \"%s\": mmap output is required to record a snapshot",
+                               channel->name);
                ret = -1;
                goto end;
        }
 
        cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
-               /* Are we at a position _before_ the first available packet ? */
-               bool before_first_packet = true;
+               unsigned long consumed_pos, produced_pos;
 
                health_code_update();
 
@@ -151,6 +172,19 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
                 */
                pthread_mutex_lock(&stream->lock);
 
+               assert(channel->trace_chunk);
+               if (!lttng_trace_chunk_get(channel->trace_chunk)) {
+                       /*
+                        * Can't happen barring an internal error as the channel
+                        * holds a reference to the trace chunk.
+                        */
+                       ERR("Failed to acquire reference to channel's trace chunk");
+                       ret = -1;
+                       goto end_unlock;
+               }
+               assert(!stream->trace_chunk);
+               stream->trace_chunk = channel->trace_chunk;
+
                /*
                 * Assign the received relayd ID so we can use it for streaming. The streams
                 * are not visible to anyone so this is OK to change it.
@@ -164,33 +198,29 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
                                goto end_unlock;
                        }
                } else {
-                       ret = utils_create_stream_file(path, stream->name,
-                                       stream->chan->tracefile_size,
-                                       stream->tracefile_count_current,
-                                       stream->uid, stream->gid, NULL);
+                       ret = consumer_stream_create_output_files(stream,
+                                       false);
                        if (ret < 0) {
-                               ERR("utils_create_stream_file");
                                goto end_unlock;
                        }
-
-                       stream->out_fd = ret;
-                       stream->tracefile_size_current = 0;
-
-                       DBG("Kernel consumer snapshot stream %s/%s (%" PRIu64 ")",
-                                       path, stream->name, stream->key);
+                       DBG("Kernel consumer snapshot stream (%" PRIu64 ")",
+                                       stream->key);
                }
-               if (relayd_id != -1ULL) {
-                       ret = consumer_send_relayd_streams_sent(relayd_id);
+
+               ret = kernctl_buffer_flush_empty(stream->wait_fd);
+               if (ret < 0) {
+                       /*
+                        * Doing a buffer flush which does not take into
+                        * account empty packets. This is not perfect
+                        * for stream intersection, but required as a
+                        * fall-back when "flush_empty" is not
+                        * implemented by lttng-modules.
+                        */
+                       ret = kernctl_buffer_flush(stream->wait_fd);
                        if (ret < 0) {
-                               ERR("sending streams sent to relayd");
+                               ERR("Failed to flush kernel stream");
                                goto end_unlock;
                        }
-               }
-
-               ret = kernctl_buffer_flush(stream->wait_fd);
-               if (ret < 0) {
-                       ERR("Failed to flush kernel stream");
-                       ret = -errno;
                        goto end_unlock;
                }
 
@@ -212,65 +242,52 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
                        goto end_unlock;
                }
 
-               if (stream->max_sb_size == 0) {
-                       ret = kernctl_get_max_subbuf_size(stream->wait_fd,
-                                       &stream->max_sb_size);
-                       if (ret < 0) {
-                               ERR("Getting kernel max_sb_size");
-                               ret = -errno;
-                               goto end_unlock;
-                       }
-               }
-
                consumed_pos = consumer_get_consume_start_pos(consumed_pos,
                                produced_pos, nb_packets_per_stream,
                                stream->max_sb_size);
 
-               while (consumed_pos < produced_pos) {
+               while ((long) (consumed_pos - produced_pos) < 0) {
                        ssize_t read_len;
                        unsigned long len, padded_len;
-                       int lost_packet = 0;
+                       const char *subbuf_addr;
+                       struct lttng_buffer_view subbuf_view;
 
                        health_code_update();
-
                        DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 
                        ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
                        if (ret < 0) {
-                               if (errno != EAGAIN) {
+                               if (ret != -EAGAIN) {
                                        PERROR("kernctl_get_subbuf snapshot");
-                                       ret = -errno;
                                        goto end_unlock;
                                }
                                DBG("Kernel consumer get subbuf failed. Skipping it.");
                                consumed_pos += stream->max_sb_size;
-
-                               /*
-                                * Start accounting lost packets only when we
-                                * already have extracted packets (to match the
-                                * content of the final snapshot).
-                                */
-                               if (!before_first_packet) {
-                                       lost_packet = 1;
-                               }
+                               stream->chan->lost_packets++;
                                continue;
                        }
 
                        ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
                        if (ret < 0) {
                                ERR("Snapshot kernctl_get_subbuf_size");
-                               ret = -errno;
                                goto error_put_subbuf;
                        }
 
                        ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
                        if (ret < 0) {
                                ERR("Snapshot kernctl_get_padded_subbuf_size");
-                               ret = -errno;
                                goto error_put_subbuf;
                        }
 
-                       read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
+                       ret = get_current_subbuf_addr(stream, &subbuf_addr);
+                       if (ret) {
+                               goto error_put_subbuf;
+                       }
+
+                       subbuf_view = lttng_buffer_view_init(
+                                       subbuf_addr, 0, padded_len);
+                       read_len = lttng_consumer_on_read_subbuffer_mmap(ctx,
+                                       stream, &subbuf_view,
                                        padded_len - len, NULL);
                        /*
                         * We write the padded len in local tracefiles but the data len
@@ -292,20 +309,9 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
                        ret = kernctl_put_subbuf(stream->wait_fd);
                        if (ret < 0) {
                                ERR("Snapshot kernctl_put_subbuf");
-                               ret = -errno;
                                goto end_unlock;
                        }
                        consumed_pos += stream->max_sb_size;
-
-                       /*
-                        * Only account lost packets located between
-                        * succesfully extracted packets (do not account before
-                        * and after since they are not visible in the
-                        * resulting snapshot).
-                        */
-                       stream->chan->lost_packets += lost_packet;
-                       lost_packet = 0;
-                       before_first_packet = false;
                }
 
                if (relayd_id == (uint64_t) -1ULL) {
@@ -321,6 +327,8 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
                        close_relayd_stream(stream);
                        stream->net_seq_idx = (uint64_t) -1ULL;
                }
+               lttng_trace_chunk_put(stream->trace_chunk);
+               stream->trace_chunk = NULL;
                pthread_mutex_unlock(&stream->lock);
        }
 
@@ -331,7 +339,6 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
 error_put_subbuf:
        ret = kernctl_put_subbuf(stream->wait_fd);
        if (ret < 0) {
-               ret = -errno;
                ERR("Snapshot kernctl_put_subbuf error path");
        }
 end_unlock:
@@ -343,15 +350,18 @@ end:
 
 /*
  * Read the whole metadata available for a snapshot.
+ * RCU read-side lock must be held across this function to ensure existence of
+ * metadata_channel. The channel lock must be held by the caller.
  *
  * Returns 0 on success, < 0 on error
  */
-int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
-               uint64_t relayd_id, struct lttng_consumer_local_data *ctx)
+static int lttng_kconsumer_snapshot_metadata(
+               struct lttng_consumer_channel *metadata_channel,
+               uint64_t key, char *path, uint64_t relayd_id,
+               struct lttng_consumer_local_data *ctx)
 {
        int ret, use_relayd = 0;
        ssize_t ret_read;
-       struct lttng_consumer_channel *metadata_channel;
        struct lttng_consumer_stream *metadata_stream;
 
        assert(ctx);
@@ -361,16 +371,13 @@ int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
 
        rcu_read_lock();
 
-       metadata_channel = consumer_find_channel(key);
-       if (!metadata_channel) {
-               ERR("Kernel snapshot metadata not found for key %" PRIu64, key);
-               ret = -1;
-               goto error;
-       }
-
        metadata_stream = metadata_channel->metadata_stream;
        assert(metadata_stream);
 
+       pthread_mutex_lock(&metadata_stream->lock);
+       assert(metadata_channel->trace_chunk);
+       assert(metadata_stream->trace_chunk);
+
        /* Flag once that we have a valid relayd for the stream. */
        if (relayd_id != (uint64_t) -1ULL) {
                use_relayd = 1;
@@ -379,17 +386,14 @@ int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
        if (use_relayd) {
                ret = consumer_send_relayd_stream(metadata_stream, path);
                if (ret < 0) {
-                       goto error;
+                       goto error_snapshot;
                }
        } else {
-               ret = utils_create_stream_file(path, metadata_stream->name,
-                               metadata_stream->chan->tracefile_size,
-                               metadata_stream->tracefile_count_current,
-                               metadata_stream->uid, metadata_stream->gid, NULL);
+               ret = consumer_stream_create_output_files(metadata_stream,
+                               false);
                if (ret < 0) {
-                       goto error;
+                       goto error_snapshot;
                }
-               metadata_stream->out_fd = ret;
        }
 
        do {
@@ -400,7 +404,8 @@ int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
                        if (ret_read != -EAGAIN) {
                                ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
                                                ret_read);
-                               goto error;
+                               ret = ret_read;
+                               goto error_snapshot;
                        }
                        /* ret_read is negative at this point so we will exit the loop. */
                        continue;
@@ -421,15 +426,17 @@ int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
                                 */
                        }
                        metadata_stream->out_fd = -1;
+                       lttng_trace_chunk_put(metadata_stream->trace_chunk);
+                       metadata_stream->trace_chunk = NULL;
                }
        }
 
        ret = 0;
-
+error_snapshot:
+       pthread_mutex_unlock(&metadata_stream->lock);
        cds_list_del(&metadata_stream->send_node);
        consumer_stream_destroy(metadata_stream, NULL);
        metadata_channel->metadata_stream = NULL;
-error:
        rcu_read_unlock();
        return ret;
 }
@@ -471,16 +478,17 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
        {
                /* Session daemon status message are handled in the following call. */
-               ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
+               consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
                                msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
                                &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
-                                msg.u.relayd_sock.relayd_session_id);
+                               msg.u.relayd_sock.relayd_session_id);
                goto end_nosignal;
        }
        case LTTNG_CONSUMER_ADD_CHANNEL:
        {
                struct lttng_consumer_channel *new_channel;
                int ret_recv;
+               const uint64_t chunk_id = msg.u.channel.chunk_id.value;
 
                health_code_update();
 
@@ -495,8 +503,11 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
                DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
                new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
-                               msg.u.channel.session_id, msg.u.channel.pathname,
-                               msg.u.channel.name, msg.u.channel.uid, msg.u.channel.gid,
+                               msg.u.channel.session_id,
+                               msg.u.channel.chunk_id.is_set ?
+                                               &chunk_id : NULL,
+                               msg.u.channel.pathname,
+                               msg.u.channel.name,
                                msg.u.channel.relayd_id, msg.u.channel.output,
                                msg.u.channel.tracefile_size,
                                msg.u.channel.tracefile_count, 0,
@@ -543,9 +554,20 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                } else {
                        ret = consumer_add_channel(new_channel, ctx);
                }
-               if (CONSUMER_CHANNEL_TYPE_DATA) {
+               if (msg.u.channel.type == CONSUMER_CHANNEL_TYPE_DATA && !ret) {
+                       int monitor_start_ret;
+
+                       DBG("Consumer starting monitor timer");
                        consumer_timer_live_start(new_channel,
                                        msg.u.channel.live_timer_interval);
+                       monitor_start_ret = consumer_timer_monitor_start(
+                                       new_channel,
+                                       msg.u.channel.monitor_timer_interval);
+                       if (monitor_start_ret < 0) {
+                               ERR("Starting channel monitoring timer failed");
+                               goto end_nosignal;
+                       }
+
                }
 
                health_code_update();
@@ -589,14 +611,14 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = consumer_send_status_msg(sock, ret_code);
                if (ret < 0) {
                        /* Somehow, the session daemon is not responding anymore. */
-                       goto error_fatal;
+                       goto error_add_stream_fatal;
                }
 
                health_code_update();
 
                if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
                        /* Channel was not found. */
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                /* Blocking call */
@@ -604,7 +626,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = lttng_consumer_poll_socket(consumer_sockpoll);
                health_poll_exit();
                if (ret) {
-                       goto error_fatal;
+                       goto error_add_stream_fatal;
                }
 
                health_code_update();
@@ -613,8 +635,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
                if (ret != sizeof(fd)) {
                        lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
-                       rcu_read_unlock();
-                       return ret;
+                       goto end;
                }
 
                health_code_update();
@@ -627,19 +648,18 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = consumer_send_status_msg(sock, ret_code);
                if (ret < 0) {
                        /* Somehow, the session daemon is not responding anymore. */
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                health_code_update();
 
+               pthread_mutex_lock(&channel->lock);
                new_stream = consumer_allocate_stream(channel->key,
                                fd,
-                               LTTNG_CONSUMER_ACTIVE_STREAM,
                                channel->name,
-                               channel->uid,
-                               channel->gid,
                                channel->relayd_id,
                                channel->session_id,
+                               channel->trace_chunk,
                                msg.u.stream.cpu,
                                &alloc_ret,
                                channel->type,
@@ -652,17 +672,29 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
                                break;
                        }
-                       goto end_nosignal;
+                       pthread_mutex_unlock(&channel->lock);
+                       goto error_add_stream_nosignal;
                }
 
                new_stream->chan = channel;
                new_stream->wait_fd = fd;
+               ret = kernctl_get_max_subbuf_size(new_stream->wait_fd,
+                               &new_stream->max_sb_size);
+               if (ret < 0) {
+                       pthread_mutex_unlock(&channel->lock);
+                       ERR("Failed to get kernel maximal subbuffer size");
+                       goto error_add_stream_nosignal;
+               }
+
+               consumer_stream_update_channel_attributes(new_stream,
+                               channel);
                switch (channel->output) {
                case CONSUMER_CHANNEL_SPLICE:
                        new_stream->output = LTTNG_EVENT_SPLICE;
                        ret = utils_create_pipe(new_stream->splice_pipe);
                        if (ret < 0) {
-                               goto end_nosignal;
+                               pthread_mutex_unlock(&channel->lock);
+                               goto error_add_stream_nosignal;
                        }
                        break;
                case CONSUMER_CHANNEL_MMAP:
@@ -670,7 +702,8 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        break;
                default:
                        ERR("Stream output unknown %d", channel->output);
-                       goto end_nosignal;
+                       pthread_mutex_unlock(&channel->lock);
+                       goto error_add_stream_nosignal;
                }
 
                /*
@@ -695,14 +728,16 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
                health_code_update();
 
+               pthread_mutex_lock(&new_stream->lock);
                if (ctx->on_recv_stream) {
                        ret = ctx->on_recv_stream(new_stream);
                        if (ret < 0) {
+                               pthread_mutex_unlock(&new_stream->lock);
+                               pthread_mutex_unlock(&channel->lock);
                                consumer_stream_free(new_stream);
-                               goto end_nosignal;
+                               goto error_add_stream_nosignal;
                        }
                }
-
                health_code_update();
 
                if (new_stream->metadata_flag) {
@@ -715,7 +750,9 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                        "relayd id %" PRIu64, new_stream->name,
                                        new_stream->net_seq_idx);
                        cds_list_add(&new_stream->send_node, &channel->streams.head);
-                       break;
+                       pthread_mutex_unlock(&new_stream->lock);
+                       pthread_mutex_unlock(&channel->lock);
+                       goto end_add_stream;
                }
 
                /* Send stream to relayd if the stream has an ID. */
@@ -723,33 +760,40 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        ret = consumer_send_relayd_stream(new_stream,
                                        new_stream->chan->pathname);
                        if (ret < 0) {
+                               pthread_mutex_unlock(&new_stream->lock);
+                               pthread_mutex_unlock(&channel->lock);
                                consumer_stream_free(new_stream);
-                               goto end_nosignal;
+                               goto error_add_stream_nosignal;
+                       }
+
+                       /*
+                        * If adding an extra stream to an already
+                        * existing channel (e.g. cpu hotplug), we need
+                        * to send the "streams_sent" command to relayd.
+                        */
+                       if (channel->streams_sent_to_relayd) {
+                               ret = consumer_send_relayd_streams_sent(
+                                               new_stream->net_seq_idx);
+                               if (ret < 0) {
+                                       pthread_mutex_unlock(&new_stream->lock);
+                                       pthread_mutex_unlock(&channel->lock);
+                                       goto error_add_stream_nosignal;
+                               }
                        }
                }
+               pthread_mutex_unlock(&new_stream->lock);
+               pthread_mutex_unlock(&channel->lock);
 
                /* Get the right pipe where the stream will be sent. */
                if (new_stream->metadata_flag) {
-                       ret = consumer_add_metadata_stream(new_stream);
-                       if (ret) {
-                               ERR("Consumer add metadata stream %" PRIu64 " failed. Continuing",
-                                               new_stream->key);
-                               consumer_stream_free(new_stream);
-                               goto end_nosignal;
-                       }
+                       consumer_add_metadata_stream(new_stream);
                        stream_pipe = ctx->consumer_metadata_pipe;
                } else {
-                       ret = consumer_add_data_stream(new_stream);
-                       if (ret) {
-                               ERR("Consumer add stream %" PRIu64 " failed. Continuing",
-                                               new_stream->key);
-                               consumer_stream_free(new_stream);
-                               goto end_nosignal;
-                       }
+                       consumer_add_data_stream(new_stream);
                        stream_pipe = ctx->consumer_data_pipe;
                }
 
-               /* Vitible to other threads */
+               /* Visible to other threads */
                new_stream->globally_visible = 1;
 
                health_code_update();
@@ -764,12 +808,17 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        } else {
                                consumer_del_stream_for_data(new_stream);
                        }
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
-               DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64,
-                               new_stream->name, fd, new_stream->relayd_stream_id);
+               DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
+                               new_stream->name, fd, new_stream->chan->pathname, new_stream->relayd_stream_id);
+end_add_stream:
                break;
+error_add_stream_nosignal:
+               goto end_nosignal;
+error_add_stream_fatal:
+               goto error_fatal;
        }
        case LTTNG_CONSUMER_STREAMS_SENT:
        {
@@ -798,7 +847,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = consumer_send_status_msg(sock, ret_code);
                if (ret < 0 || ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
                        /* Somehow, the session daemon is not responding anymore. */
-                       goto end_nosignal;
+                       goto error_streams_sent_nosignal;
                }
 
                health_code_update();
@@ -808,7 +857,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                 * streams in this channel.
                 */
                if (!channel->monitor) {
-                       break;
+                       goto end_error_streams_sent;
                }
 
                health_code_update();
@@ -817,10 +866,14 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        ret = consumer_send_relayd_streams_sent(
                                        msg.u.sent_streams.net_seq_idx);
                        if (ret < 0) {
-                               goto end_nosignal;
+                               goto error_streams_sent_nosignal;
                        }
+                       channel->streams_sent_to_relayd = true;
                }
+end_error_streams_sent:
                break;
+error_streams_sent_nosignal:
+               goto end_nosignal;
        }
        case LTTNG_CONSUMER_UPDATE_STREAM:
        {
@@ -891,26 +944,36 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        }
        case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
        {
-               if (msg.u.snapshot_channel.metadata == 1) {
-                       ret = lttng_kconsumer_snapshot_metadata(msg.u.snapshot_channel.key,
-                                       msg.u.snapshot_channel.pathname,
-                                       msg.u.snapshot_channel.relayd_id, ctx);
-                       if (ret < 0) {
-                               ERR("Snapshot metadata failed");
-                               ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
-                       }
+               struct lttng_consumer_channel *channel;
+               uint64_t key = msg.u.snapshot_channel.key;
+
+               channel = consumer_find_channel(key);
+               if (!channel) {
+                       ERR("Channel %" PRIu64 " not found", key);
+                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
                } else {
-                       ret = lttng_kconsumer_snapshot_channel(msg.u.snapshot_channel.key,
-                                       msg.u.snapshot_channel.pathname,
-                                       msg.u.snapshot_channel.relayd_id,
-                                       msg.u.snapshot_channel.nb_packets_per_stream,
-                                       ctx);
-                       if (ret < 0) {
-                               ERR("Snapshot channel failed");
-                               ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
+                       pthread_mutex_lock(&channel->lock);
+                       if (msg.u.snapshot_channel.metadata == 1) {
+                               ret = lttng_kconsumer_snapshot_metadata(channel, key,
+                                               msg.u.snapshot_channel.pathname,
+                                               msg.u.snapshot_channel.relayd_id, ctx);
+                               if (ret < 0) {
+                                       ERR("Snapshot metadata failed");
+                                       ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
+                               }
+                       } else {
+                               ret = lttng_kconsumer_snapshot_channel(channel, key,
+                                               msg.u.snapshot_channel.pathname,
+                                               msg.u.snapshot_channel.relayd_id,
+                                               msg.u.snapshot_channel.nb_packets_per_stream,
+                                               ctx);
+                               if (ret < 0) {
+                                       ERR("Snapshot channel failed");
+                                       ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
+                               }
                        }
+                       pthread_mutex_unlock(&channel->lock);
                }
-
                health_code_update();
 
                ret = consumer_send_status_msg(sock, ret_code);
@@ -936,14 +999,14 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = consumer_send_status_msg(sock, ret_code);
                if (ret < 0) {
                        /* Somehow, the session daemon is not responding anymore. */
-                       goto end_nosignal;
+                       goto end_destroy_channel;
                }
 
                health_code_update();
 
                /* Stop right now if no channel was found. */
                if (!channel) {
-                       goto end_nosignal;
+                       goto end_destroy_channel;
                }
 
                /*
@@ -959,12 +1022,13 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                assert(!uatomic_sub_return(&channel->refcount, 1));
 
                consumer_del_channel(channel);
-
+end_destroy_channel:
                goto end_nosignal;
        }
        case LTTNG_CONSUMER_DISCARDED_EVENTS:
        {
-               uint64_t ret;
+               ssize_t ret;
+               uint64_t count;
                struct lttng_consumer_channel *channel;
                uint64_t id = msg.u.discarded_events.session_id;
                uint64_t key = msg.u.discarded_events.channel_key;
@@ -976,15 +1040,15 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                if (!channel) {
                        ERR("Kernel consumer discarded events channel %"
                                        PRIu64 " not found", key);
-                       ret = 0;
+                       count = 0;
                } else {
-                       ret = channel->discarded_events;
+                       count = channel->discarded_events;
                }
 
                health_code_update();
 
                /* Send back returned value to session daemon */
-               ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
+               ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
                if (ret < 0) {
                        PERROR("send discarded events");
                        goto error_fatal;
@@ -994,7 +1058,8 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        }
        case LTTNG_CONSUMER_LOST_PACKETS:
        {
-               uint64_t ret;
+               ssize_t ret;
+               uint64_t count;
                struct lttng_consumer_channel *channel;
                uint64_t id = msg.u.lost_packets.session_id;
                uint64_t key = msg.u.lost_packets.channel_key;
@@ -1006,15 +1071,15 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                if (!channel) {
                        ERR("Kernel consumer lost packets channel %"
                                        PRIu64 " not found", key);
-                       ret = 0;
+                       count = 0;
                } else {
-                       ret = channel->lost_packets;
+                       count = channel->lost_packets;
                }
 
                health_code_update();
 
                /* Send back returned value to session daemon */
-               ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
+               ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
                if (ret < 0) {
                        PERROR("send lost packets");
                        goto error_fatal;
@@ -1022,24 +1087,273 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
                break;
        }
+       case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
+       {
+               int channel_monitor_pipe;
+
+               ret_code = LTTCOMM_CONSUMERD_SUCCESS;
+               /* Successfully received the command's type. */
+               ret = consumer_send_status_msg(sock, ret_code);
+               if (ret < 0) {
+                       goto error_fatal;
+               }
+
+               ret = lttcomm_recv_fds_unix_sock(sock, &channel_monitor_pipe,
+                               1);
+               if (ret != sizeof(channel_monitor_pipe)) {
+                       ERR("Failed to receive channel monitor pipe");
+                       goto error_fatal;
+               }
+
+               DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
+               ret = consumer_timer_thread_set_channel_monitor_pipe(
+                               channel_monitor_pipe);
+               if (!ret) {
+                       int flags;
+
+                       ret_code = LTTCOMM_CONSUMERD_SUCCESS;
+                       /* Set the pipe as non-blocking. */
+                       ret = fcntl(channel_monitor_pipe, F_GETFL, 0);
+                       if (ret == -1) {
+                               PERROR("fcntl get flags of the channel monitoring pipe");
+                               goto error_fatal;
+                       }
+                       flags = ret;
+
+                       ret = fcntl(channel_monitor_pipe, F_SETFL,
+                                       flags | O_NONBLOCK);
+                       if (ret == -1) {
+                               PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
+                               goto error_fatal;
+                       }
+                       DBG("Channel monitor pipe set as non-blocking");
+               } else {
+                       ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
+               }
+               ret = consumer_send_status_msg(sock, ret_code);
+               if (ret < 0) {
+                       goto error_fatal;
+               }
+               break;
+       }
+       case LTTNG_CONSUMER_ROTATE_CHANNEL:
+       {
+               struct lttng_consumer_channel *channel;
+               uint64_t key = msg.u.rotate_channel.key;
+
+               DBG("Consumer rotate channel %" PRIu64, key);
+
+               channel = consumer_find_channel(key);
+               if (!channel) {
+                       ERR("Channel %" PRIu64 " not found", key);
+                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
+               } else {
+                       /*
+                        * Sample the rotate position of all the streams in this channel.
+                        */
+                       ret = lttng_consumer_rotate_channel(channel, key,
+                                       msg.u.rotate_channel.relayd_id,
+                                       msg.u.rotate_channel.metadata,
+                                       ctx);
+                       if (ret < 0) {
+                               ERR("Rotate channel failed");
+                               ret_code = LTTCOMM_CONSUMERD_ROTATION_FAIL;
+                       }
+
+                       health_code_update();
+               }
+               ret = consumer_send_status_msg(sock, ret_code);
+               if (ret < 0) {
+                       /* Somehow, the session daemon is not responding anymore. */
+                       goto error_rotate_channel;
+               }
+               if (channel) {
+                       /* Rotate the streams that are ready right now. */
+                       ret = lttng_consumer_rotate_ready_streams(
+                                       channel, key, ctx);
+                       if (ret < 0) {
+                               ERR("Rotate ready streams failed");
+                       }
+               }
+               break;
+error_rotate_channel:
+               goto end_nosignal;
+       }
+       case LTTNG_CONSUMER_CLEAR_CHANNEL:
+       {
+               struct lttng_consumer_channel *channel;
+               uint64_t key = msg.u.clear_channel.key;
+
+               channel = consumer_find_channel(key);
+               if (!channel) {
+                       DBG("Channel %" PRIu64 " not found", key);
+                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
+               } else {
+                       ret = lttng_consumer_clear_channel(channel);
+                       if (ret) {
+                               ERR("Clear channel failed");
+                               ret_code = ret;
+                       }
+
+                       health_code_update();
+               }
+               ret = consumer_send_status_msg(sock, ret_code);
+               if (ret < 0) {
+                       /* Somehow, the session daemon is not responding anymore. */
+                       goto end_nosignal;
+               }
+
+               break;
+       }
+       case LTTNG_CONSUMER_INIT:
+       {
+               ret_code = lttng_consumer_init_command(ctx,
+                               msg.u.init.sessiond_uuid);
+               health_code_update();
+               ret = consumer_send_status_msg(sock, ret_code);
+               if (ret < 0) {
+                       /* Somehow, the session daemon is not responding anymore. */
+                       goto end_nosignal;
+               }
+               break;
+       }
+       case LTTNG_CONSUMER_CREATE_TRACE_CHUNK:
+       {
+               const struct lttng_credentials credentials = {
+                       .uid = msg.u.create_trace_chunk.credentials.value.uid,
+                       .gid = msg.u.create_trace_chunk.credentials.value.gid,
+               };
+               const bool is_local_trace =
+                               !msg.u.create_trace_chunk.relayd_id.is_set;
+               const uint64_t relayd_id =
+                               msg.u.create_trace_chunk.relayd_id.value;
+               const char *chunk_override_name =
+                               *msg.u.create_trace_chunk.override_name ?
+                                       msg.u.create_trace_chunk.override_name :
+                                       NULL;
+               struct lttng_directory_handle *chunk_directory_handle = NULL;
+
+               /*
+                * The session daemon will only provide a chunk directory file
+                * descriptor for local traces.
+                */
+               if (is_local_trace) {
+                       int chunk_dirfd;
+
+                       /* Acnowledge the reception of the command. */
+                       ret = consumer_send_status_msg(sock,
+                                       LTTCOMM_CONSUMERD_SUCCESS);
+                       if (ret < 0) {
+                               /* Somehow, the session daemon is not responding anymore. */
+                               goto end_nosignal;
+                       }
+
+                       ret = lttcomm_recv_fds_unix_sock(sock, &chunk_dirfd, 1);
+                       if (ret != sizeof(chunk_dirfd)) {
+                               ERR("Failed to receive trace chunk directory file descriptor");
+                               goto error_fatal;
+                       }
+
+                       DBG("Received trace chunk directory fd (%d)",
+                                       chunk_dirfd);
+                       chunk_directory_handle = lttng_directory_handle_create_from_dirfd(
+                                       chunk_dirfd);
+                       if (!chunk_directory_handle) {
+                               ERR("Failed to initialize chunk directory handle from directory file descriptor");
+                               if (close(chunk_dirfd)) {
+                                       PERROR("Failed to close chunk directory file descriptor");
+                               }
+                               goto error_fatal;
+                       }
+               }
+
+               ret_code = lttng_consumer_create_trace_chunk(
+                               !is_local_trace ? &relayd_id : NULL,
+                               msg.u.create_trace_chunk.session_id,
+                               msg.u.create_trace_chunk.chunk_id,
+                               (time_t) msg.u.create_trace_chunk
+                                               .creation_timestamp,
+                               chunk_override_name,
+                               msg.u.create_trace_chunk.credentials.is_set ?
+                                               &credentials :
+                                               NULL,
+                               chunk_directory_handle);
+               lttng_directory_handle_put(chunk_directory_handle);
+               goto end_msg_sessiond;
+       }
+       case LTTNG_CONSUMER_CLOSE_TRACE_CHUNK:
+       {
+               enum lttng_trace_chunk_command_type close_command =
+                               msg.u.close_trace_chunk.close_command.value;
+               const uint64_t relayd_id =
+                               msg.u.close_trace_chunk.relayd_id.value;
+               struct lttcomm_consumer_close_trace_chunk_reply reply;
+               char path[LTTNG_PATH_MAX];
+
+               ret_code = lttng_consumer_close_trace_chunk(
+                               msg.u.close_trace_chunk.relayd_id.is_set ?
+                                               &relayd_id :
+                                               NULL,
+                               msg.u.close_trace_chunk.session_id,
+                               msg.u.close_trace_chunk.chunk_id,
+                               (time_t) msg.u.close_trace_chunk.close_timestamp,
+                               msg.u.close_trace_chunk.close_command.is_set ?
+                                               &close_command :
+                                               NULL, path);
+               reply.ret_code = ret_code;
+               reply.path_length = strlen(path) + 1;
+               ret = lttcomm_send_unix_sock(sock, &reply, sizeof(reply));
+               if (ret != sizeof(reply)) {
+                       goto error_fatal;
+               }
+               ret = lttcomm_send_unix_sock(sock, path, reply.path_length);
+               if (ret != reply.path_length) {
+                       goto error_fatal;
+               }
+               goto end_nosignal;
+       }
+       case LTTNG_CONSUMER_TRACE_CHUNK_EXISTS:
+       {
+               const uint64_t relayd_id =
+                               msg.u.trace_chunk_exists.relayd_id.value;
+
+               ret_code = lttng_consumer_trace_chunk_exists(
+                               msg.u.trace_chunk_exists.relayd_id.is_set ?
+                                               &relayd_id : NULL,
+                               msg.u.trace_chunk_exists.session_id,
+                               msg.u.trace_chunk_exists.chunk_id);
+               goto end_msg_sessiond;
+       }
        default:
                goto end_nosignal;
        }
 
 end_nosignal:
-       rcu_read_unlock();
-
        /*
         * Return 1 to indicate success since the 0 value can be a socket
         * shutdown during the recv() or send() call.
         */
-       health_code_update();
-       return 1;
-
+       ret = 1;
+       goto end;
 error_fatal:
-       rcu_read_unlock();
        /* This will issue a consumer stop. */
-       return -1;
+       ret = -1;
+       goto end;
+end_msg_sessiond:
+       /*
+        * The returned value here is not useful since either way we'll return 1 to
+        * the caller because the session daemon socket management is done
+        * elsewhere. Returning a negative code or 0 will shutdown the consumer.
+        */
+       ret = consumer_send_status_msg(sock, ret_code);
+       if (ret < 0) {
+               goto error_fatal;
+       }
+       ret = 1;
+end:
+       health_code_update();
+       rcu_read_unlock();
+       return ret;
 }
 
 /*
@@ -1050,63 +1364,82 @@ error_fatal:
 static int get_index_values(struct ctf_packet_index *index, int infd)
 {
        int ret;
+       uint64_t packet_size, content_size, timestamp_begin, timestamp_end,
+                       events_discarded, stream_id, stream_instance_id,
+                       packet_seq_num;
 
-       ret = kernctl_get_timestamp_begin(infd, &index->timestamp_begin);
+       ret = kernctl_get_timestamp_begin(infd, &timestamp_begin);
        if (ret < 0) {
                PERROR("kernctl_get_timestamp_begin");
                goto error;
        }
-       index->timestamp_begin = htobe64(index->timestamp_begin);
 
-       ret = kernctl_get_timestamp_end(infd, &index->timestamp_end);
+       ret = kernctl_get_timestamp_end(infd, &timestamp_end);
        if (ret < 0) {
                PERROR("kernctl_get_timestamp_end");
                goto error;
        }
-       index->timestamp_end = htobe64(index->timestamp_end);
 
-       ret = kernctl_get_events_discarded(infd, &index->events_discarded);
+       ret = kernctl_get_events_discarded(infd, &events_discarded);
        if (ret < 0) {
                PERROR("kernctl_get_events_discarded");
                goto error;
        }
-       index->events_discarded = htobe64(index->events_discarded);
 
-       ret = kernctl_get_content_size(infd, &index->content_size);
+       ret = kernctl_get_content_size(infd, &content_size);
        if (ret < 0) {
                PERROR("kernctl_get_content_size");
                goto error;
        }
-       index->content_size = htobe64(index->content_size);
 
-       ret = kernctl_get_packet_size(infd, &index->packet_size);
+       ret = kernctl_get_packet_size(infd, &packet_size);
        if (ret < 0) {
                PERROR("kernctl_get_packet_size");
                goto error;
        }
-       index->packet_size = htobe64(index->packet_size);
 
-       ret = kernctl_get_stream_id(infd, &index->stream_id);
+       ret = kernctl_get_stream_id(infd, &stream_id);
        if (ret < 0) {
                PERROR("kernctl_get_stream_id");
                goto error;
        }
-       index->stream_id = htobe64(index->stream_id);
 
-       ret = kernctl_get_instance_id(infd, &index->stream_instance_id);
+       ret = kernctl_get_instance_id(infd, &stream_instance_id);
        if (ret < 0) {
-               PERROR("kernctl_get_instance_id");
-               goto error;
+               if (ret == -ENOTTY) {
+                       /* Command not implemented by lttng-modules. */
+                       stream_instance_id = -1ULL;
+               } else {
+                       PERROR("kernctl_get_instance_id");
+                       goto error;
+               }
        }
-       index->stream_instance_id = htobe64(index->stream_instance_id);
 
-       ret = kernctl_get_sequence_number(infd, &index->packet_seq_num);
+       ret = kernctl_get_sequence_number(infd, &packet_seq_num);
        if (ret < 0) {
-               PERROR("kernctl_get_sequence_number");
-               goto error;
+               if (ret == -ENOTTY) {
+                       /* Command not implemented by lttng-modules. */
+                       packet_seq_num = -1ULL;
+                       ret = 0;
+               } else {
+                       PERROR("kernctl_get_sequence_number");
+                       goto error;
+               }
        }
        index->packet_seq_num = htobe64(index->packet_seq_num);
 
+       *index = (typeof(*index)) {
+               .offset = index->offset,
+               .packet_size = htobe64(packet_size),
+               .content_size = htobe64(content_size),
+               .timestamp_begin = htobe64(timestamp_begin),
+               .timestamp_end = htobe64(timestamp_end),
+               .events_discarded = htobe64(events_discarded),
+               .stream_id = htobe64(stream_id),
+               .stream_instance_id = htobe64(stream_instance_id),
+               .packet_seq_num = htobe64(packet_seq_num),
+       };
+
 error:
        return ret;
 }
@@ -1133,7 +1466,7 @@ int lttng_kconsumer_sync_metadata(struct lttng_consumer_stream *metadata)
 
        ret = kernctl_snapshot(metadata->wait_fd);
        if (ret < 0) {
-               if (errno != EAGAIN) {
+               if (ret != -EAGAIN) {
                        ERR("Sync metadata, taking kernel snapshot failed.");
                        goto end;
                }
@@ -1155,8 +1488,14 @@ int update_stream_stats(struct lttng_consumer_stream *stream)
 
        ret = kernctl_get_sequence_number(stream->wait_fd, &seq);
        if (ret < 0) {
-               PERROR("kernctl_get_sequence_number");
-               goto end;
+               if (ret == -ENOTTY) {
+                       /* Command not implemented by lttng-modules. */
+                       seq = -1ULL;
+                       stream->sequence_number_unavailable = true;
+               } else {
+                       PERROR("kernctl_get_sequence_number");
+                       goto end;
+               }
        }
 
        /*
@@ -1215,6 +1554,14 @@ int metadata_stream_check_version(int infd, struct lttng_consumer_stream *stream
 
        ret = kernctl_get_metadata_version(infd, &cur_version);
        if (ret < 0) {
+               if (ret == -ENOTTY) {
+                       /*
+                        * LTTng-modules does not implement this
+                        * command.
+                        */
+                       ret = 0;
+                       goto end;
+               }
                ERR("Failed to get the metadata version");
                goto end;
        }
@@ -1235,18 +1582,33 @@ end:
 
 /*
  * Consume data on a file descriptor and write it on a trace file.
+ * The stream and channel locks must be held by the caller.
  */
 ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                struct lttng_consumer_local_data *ctx)
 {
        unsigned long len, subbuf_size, padding;
-       int err, write_index = 1;
+       int err, write_index = 1, rotation_ret;
        ssize_t ret = 0;
        int infd = stream->wait_fd;
-       struct ctf_packet_index index;
+       struct ctf_packet_index index = {};
 
        DBG("In read_subbuffer (infd : %d)", infd);
 
+       /*
+        * If the stream was flagged to be ready for rotation before we extract the
+        * next packet, rotate it now.
+        */
+       if (stream->rotate_ready) {
+               DBG("Rotate stream before extracting data");
+               rotation_ret = lttng_consumer_rotate_stream(ctx, stream);
+               if (rotation_ret < 0) {
+                       ERR("Stream rotation error");
+                       ret = -1;
+                       goto error;
+               }
+       }
+
        /* Get the next subbuffer */
        err = kernctl_get_next_subbuf(infd);
        if (err != 0) {
@@ -1258,8 +1620,8 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                 */
                DBG("Reserving sub buffer failed (everything is normal, "
                                "it is due to concurrency)");
-               ret = -errno;
-               goto end;
+               ret = err;
+               goto error;
        }
 
        /* Get the full subbuffer size including padding */
@@ -1268,17 +1630,17 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                PERROR("Getting sub-buffer len failed.");
                err = kernctl_put_subbuf(infd);
                if (err != 0) {
-                       if (errno == EFAULT) {
+                       if (err == -EFAULT) {
                                PERROR("Error in unreserving sub buffer\n");
-                       } else if (errno == EIO) {
+                       } else if (err == -EIO) {
                                /* Should never happen with newer LTTng versions */
                                PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
                        }
-                       ret = -errno;
-                       goto end;
+                       ret = err;
+                       goto error;
                }
-               ret = -errno;
-               goto end;
+               ret = err;
+               goto error;
        }
 
        if (!stream->metadata_flag) {
@@ -1286,26 +1648,48 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                if (ret < 0) {
                        err = kernctl_put_subbuf(infd);
                        if (err != 0) {
-                               if (errno == EFAULT) {
+                               if (err == -EFAULT) {
                                        PERROR("Error in unreserving sub buffer\n");
-                               } else if (errno == EIO) {
+                               } else if (err == -EIO) {
                                        /* Should never happen with newer LTTng versions */
                                        PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
                                }
-                               ret = -errno;
-                               goto end;
+                               ret = err;
+                               goto error;
                        }
-                       goto end;
+                       goto error;
                }
                ret = update_stream_stats(stream);
                if (ret < 0) {
-                       goto end;
+                       err = kernctl_put_subbuf(infd);
+                       if (err != 0) {
+                               if (err == -EFAULT) {
+                                       PERROR("Error in unreserving sub buffer\n");
+                               } else if (err == -EIO) {
+                                       /* Should never happen with newer LTTng versions */
+                                       PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
+                               }
+                               ret = err;
+                               goto error;
+                       }
+                       goto error;
                }
        } else {
                write_index = 0;
                ret = metadata_stream_check_version(infd, stream);
                if (ret < 0) {
-                       goto end;
+                       err = kernctl_put_subbuf(infd);
+                       if (err != 0) {
+                               if (err == -EFAULT) {
+                                       PERROR("Error in unreserving sub buffer\n");
+                               } else if (err == -EIO) {
+                                       /* Should never happen with newer LTTng versions */
+                                       PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
+                               }
+                               ret = err;
+                               goto error;
+                       }
+                       goto error;
                }
        }
 
@@ -1337,23 +1721,32 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                }
                break;
        case CONSUMER_CHANNEL_MMAP:
+       {
+               const char *subbuf_addr;
+               struct lttng_buffer_view subbuf_view;
+
                /* Get subbuffer size without padding */
                err = kernctl_get_subbuf_size(infd, &subbuf_size);
                if (err != 0) {
                        PERROR("Getting sub-buffer len failed.");
                        err = kernctl_put_subbuf(infd);
                        if (err != 0) {
-                               if (errno == EFAULT) {
+                               if (err == -EFAULT) {
                                        PERROR("Error in unreserving sub buffer\n");
-                               } else if (errno == EIO) {
+                               } else if (err == -EIO) {
                                        /* Should never happen with newer LTTng versions */
                                        PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
                                }
-                               ret = -errno;
-                               goto end;
+                               ret = err;
+                               goto error;
                        }
-                       ret = -errno;
-                       goto end;
+                       ret = err;
+                       goto error;
+               }
+
+               ret = get_current_subbuf_addr(stream, &subbuf_addr);
+               if (ret) {
+                       goto error_put_subbuf;
                }
 
                /* Make sure the tracer is not gone mad on us! */
@@ -1361,13 +1754,15 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 
                padding = len - subbuf_size;
 
+               subbuf_view = lttng_buffer_view_init(subbuf_addr, 0, len);
+
                /* write the subbuffer to the tracefile */
-               ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
-                               padding, &index);
+               ret = lttng_consumer_on_read_subbuffer_mmap(
+                               ctx, stream, &subbuf_view, padding, &index);
                /*
-                * The mmap operation should write subbuf_size amount of data when
-                * network streaming or the full padding (len) size when we are _not_
-                * streaming.
+                * The mmap operation should write subbuf_size amount of data
+                * when network streaming or the full padding (len) size when we
+                * are _not_ streaming.
                 */
                if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
                                (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
@@ -1382,26 +1777,27 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                        write_index = 0;
                }
                break;
+       }
        default:
                ERR("Unknown output method");
                ret = -EPERM;
        }
-
+error_put_subbuf:
        err = kernctl_put_next_subbuf(infd);
        if (err != 0) {
-               if (errno == EFAULT) {
+               if (err == -EFAULT) {
                        PERROR("Error in unreserving sub buffer\n");
-               } else if (errno == EIO) {
+               } else if (err == -EIO) {
                        /* Should never happen with newer LTTng versions */
                        PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
                }
-               ret = -errno;
-               goto end;
+               ret = err;
+               goto error;
        }
 
        /* Write index if needed. */
        if (!write_index) {
-               goto end;
+               goto rotate;
        }
 
        if (stream->chan->live_timer_interval && !stream->metadata_flag) {
@@ -1425,16 +1821,35 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                        pthread_mutex_unlock(&stream->metadata_timer_lock);
                }
                if (err < 0) {
-                       goto end;
+                       goto error;
                }
        }
 
        err = consumer_stream_write_index(stream, &index);
        if (err < 0) {
-               goto end;
+               goto error;
        }
 
-end:
+rotate:
+       /*
+        * After extracting the packet, we check if the stream is now ready to be
+        * rotated and perform the action immediately.
+        */
+       rotation_ret = lttng_consumer_stream_is_rotate_ready(stream);
+       if (rotation_ret == 1) {
+               rotation_ret = lttng_consumer_rotate_stream(ctx, stream);
+               if (rotation_ret < 0) {
+                       ERR("Stream rotation error");
+                       ret = -1;
+                       goto error;
+               }
+       } else if (rotation_ret < 0) {
+               ERR("Checking if stream is ready to rotate");
+               ret = -1;
+               goto error;
+       }
+
+error:
        return ret;
 }
 
@@ -1445,29 +1860,15 @@ int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
        assert(stream);
 
        /*
-        * Don't create anything if this is set for streaming or should not be
-        * monitored.
+        * Don't create anything if this is set for streaming or if there is
+        * no current trace chunk on the parent channel.
         */
-       if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor) {
-               ret = utils_create_stream_file(stream->chan->pathname, stream->name,
-                               stream->chan->tracefile_size, stream->tracefile_count_current,
-                               stream->uid, stream->gid, NULL);
-               if (ret < 0) {
+       if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor &&
+                       stream->chan->trace_chunk) {
+               ret = consumer_stream_create_output_files(stream, true);
+               if (ret) {
                        goto error;
                }
-               stream->out_fd = ret;
-               stream->tracefile_size_current = 0;
-
-               if (!stream->metadata_flag) {
-                       ret = index_create_file(stream->chan->pathname,
-                                       stream->name, stream->uid, stream->gid,
-                                       stream->chan->tracefile_size,
-                                       stream->tracefile_count_current);
-                       if (ret < 0) {
-                               goto error;
-                       }
-                       stream->index_fd = ret;
-               }
        }
 
        if (stream->output == LTTNG_EVENT_MMAP) {
@@ -1477,7 +1878,6 @@ int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
                ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
                if (ret != 0) {
                        PERROR("kernctl_get_mmap_len");
-                       ret = -errno;
                        goto error_close_fd;
                }
                stream->mmap_len = (size_t) mmap_len;
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