From: David Goulet <dgoulet@efficios.com>
Date: Wed, 26 Feb 2014 20:07:12 +0000 (-0500)
Subject: Fix: keep metadata channel attr in UST session
X-Git-Tag: v2.4.0~9
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=4e4e68f4fe6af2d8c4b2f1b60a3ec3fa8365d2a1;p=lttng-tools.git

Fix: keep metadata channel attr in UST session

This is so that if we have NO application we can use the metadata
channel attributes once one appears.

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/channel.c b/src/bin/lttng-sessiond/channel.c
index fc343f591..1d04b1fcf 100644
--- a/src/bin/lttng-sessiond/channel.c
+++ b/src/bin/lttng-sessiond/channel.c
@@ -369,6 +369,14 @@ int channel_ust_create(struct ltt_ust_session *usess,
 	if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
 				sizeof(uchan->name))) {
 		lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
+	} else {
+		/*
+		 * Copy channel attribute to session if this is metadata so if NO
+		 * application exists we can access that data in the shadow copy during
+		 * the global update of newly registered application.
+		 */
+		memcpy(&usess->metadata_attr, &uchan->attr,
+				sizeof(usess->metadata_attr));
 	}
 	rcu_read_unlock();
 
diff --git a/src/bin/lttng-sessiond/trace-ust.c b/src/bin/lttng-sessiond/trace-ust.c
index c08246a25..996916558 100644
--- a/src/bin/lttng-sessiond/trace-ust.c
+++ b/src/bin/lttng-sessiond/trace-ust.c
@@ -220,6 +220,14 @@ struct ltt_ust_session *trace_ust_create_session(uint64_t session_id)
 	lus->id = session_id;
 	lus->start_trace = 0;
 
+	/* Set default metadata channel attribute. */
+	lus->metadata_attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
+	lus->metadata_attr.subbuf_size = default_get_metadata_subbuf_size();
+	lus->metadata_attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
+	lus->metadata_attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
+	lus->metadata_attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;
+	lus->metadata_attr.output = LTTNG_UST_MMAP;
+
 	/*
 	 * Default buffer type. This can be changed through an enable channel
 	 * requesting a different type. Note that this can only be changed once
diff --git a/src/bin/lttng-sessiond/trace-ust.h b/src/bin/lttng-sessiond/trace-ust.h
index 07af0f1ee..6c6c6c454 100644
--- a/src/bin/lttng-sessiond/trace-ust.h
+++ b/src/bin/lttng-sessiond/trace-ust.h
@@ -107,6 +107,9 @@ struct ltt_ust_session {
 	unsigned int snapshot_mode;
 	unsigned int has_non_default_channel;
 	unsigned int live_timer_interval;	/* usec */
+
+	/* Metadata channel attributes. */
+	struct lttng_ust_channel_attr metadata_attr;
 };
 
 /*
diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 5aad28bbc..00c6d9622 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -825,16 +825,8 @@ struct ust_app_session *alloc_ust_app_session(struct ust_app *app)
 
 	ua_sess->handle = -1;
 	ua_sess->channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
-	pthread_mutex_init(&ua_sess->lock, NULL);
-
-	/* Set default metadata channel attribute. */
-	ua_sess->metadata_attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
-	ua_sess->metadata_attr.subbuf_size = default_get_metadata_subbuf_size();
-	ua_sess->metadata_attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
-	ua_sess->metadata_attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
-	ua_sess->metadata_attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;
-	ua_sess->metadata_attr.output = LTTNG_UST_MMAP;
 	ua_sess->metadata_attr.type = LTTNG_UST_CHAN_METADATA;
+	pthread_mutex_init(&ua_sess->lock, NULL);
 
 	return ua_sess;
 
@@ -1617,6 +1609,8 @@ static void shadow_copy_session(struct ust_app_session *ua_sess,
 	ua_sess->consumer = usess->consumer;
 	ua_sess->output_traces = usess->output_traces;
 	ua_sess->live_timer_interval = usess->live_timer_interval;
+	copy_channel_attr_to_ustctl(&ua_sess->metadata_attr,
+			&usess->metadata_attr);
 
 	switch (ua_sess->buffer_type) {
 	case LTTNG_BUFFER_PER_PID: