Fix: relayd: failure to read index entry or stream packet after clear

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

diff --git a/src/bin/lttng-relayd/viewer-stream.c b/src/bin/lttng-relayd/viewer-stream.c
index 9d852b661ab420332308fb5d16a75fe093326dd0..67c452eec7d4264139f1134b1fcdd4bc2aa2d49c 100644 (file)
--- a/src/bin/lttng-relayd/viewer-stream.c
+++ b/src/bin/lttng-relayd/viewer-stream.c
@@ -1,20 +1,10 @@
 /*
- * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
- *                      David Goulet <dgoulet@efficios.com>
- *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 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.
+ * 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.
  */
 
 #define _LGPL_SOURCE
@@ -31,6 +21,7 @@
 
 static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
 {
+       lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
        free(vstream->path_name);
        free(vstream->channel_name);
        free(vstream);
@@ -44,17 +35,14 @@ static void viewer_stream_destroy_rcu(struct rcu_head *head)
        viewer_stream_destroy(vstream);
 }
 
+/* Relay stream's lock must be held by the caller. */
 struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
-               struct lttng_trace_chunk *viewer_trace_chunk,
+               struct lttng_trace_chunk *trace_chunk,
                enum lttng_viewer_seek seek_t)
 {
        struct relay_viewer_stream *vstream = NULL;
-       const bool acquired_reference = lttng_trace_chunk_get(
-                       viewer_trace_chunk);
 
-       if (!acquired_reference) {
-               goto error;
-       }
+       ASSERT_LOCKED(stream->lock);
 
        vstream = zmalloc(sizeof(*vstream));
        if (!vstream) {
@@ -62,8 +50,14 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
                goto error;
        }
 
-       vstream->stream_file.trace_chunk = viewer_trace_chunk;
-       viewer_trace_chunk = NULL;
+       if (trace_chunk) {
+               const bool acquired_reference = lttng_trace_chunk_get(
+                               trace_chunk);
+
+               assert(acquired_reference);
+       }
+
+       vstream->stream_file.trace_chunk = trace_chunk;
        vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
        if (vstream->path_name == NULL) {
                PERROR("relay viewer path_name alloc");
@@ -82,11 +76,9 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
        }
        vstream->stream = stream;
 
-       pthread_mutex_lock(&stream->lock);
-
        if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
                ERR("Cannot attach viewer metadata stream to trace (busy).");
-               goto error_unlock;
+               goto error;
        }
 
        switch (seek_t) {
@@ -121,7 +113,7 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
                                tracefile_array_get_seq_head(stream->tfa) + 1;
                break;
        default:
-               goto error_unlock;
+               goto error;
        }
 
        /*
@@ -149,7 +141,7 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
                        if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
                                vstream->index_file = NULL;
                        } else {
-                               goto error_unlock;
+                               goto error;
                        }
                }
        }
@@ -168,7 +160,7 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
                                vstream->current_tracefile_id, NULL, file_path,
                                sizeof(file_path));
                if (ret < 0) {
-                       goto error_unlock;
+                       goto error;
                }
 
                status = lttng_trace_chunk_open_fs_handle(
@@ -176,7 +168,7 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
                                O_RDONLY, 0, &vstream->stream_file.handle,
                                true);
                if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
-                       goto error_unlock;
+                       goto error;
                }
        }
 
@@ -186,14 +178,15 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
                lseek_ret = fs_handle_seek(
                                vstream->index_file->file, 0, SEEK_END);
                if (lseek_ret < 0) {
-                       goto error_unlock;
+                       goto error;
                }
        }
        if (stream->is_metadata) {
                rcu_assign_pointer(stream->trace->viewer_metadata_stream,
                                vstream);
        }
-       pthread_mutex_unlock(&stream->lock);
+
+       vstream->last_seen_rotation_count = stream->completed_rotation_count;
 
        /* Globally visible after the add unique. */
        lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
@@ -202,15 +195,10 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
 
        return vstream;
 
-error_unlock:
-       pthread_mutex_unlock(&stream->lock);
 error:
        if (vstream) {
                viewer_stream_destroy(vstream);
        }
-       if (viewer_trace_chunk && acquired_reference) {
-               lttng_trace_chunk_put(viewer_trace_chunk);
-       }
        return NULL;
 }