stream->ongoing_rotation = (typeof(stream->ongoing_rotation)) {};
}
-/*
- * If too much data has been written in a tracefile before we received the
- * rotation command, we have to move the excess data to the new tracefile and
- * perform the rotation. This can happen because the control and data
- * connections are separate, the indexes as well as the commands arrive from
- * the control connection and we have no control over the order so we could be
- * in a situation where too much data has been received on the data connection
- * before the rotation command on the control connection arrives.
- */
-static int rotate_truncate_stream(struct relay_stream *stream)
-{
- int ret, new_fd;
- off_t lseek_ret;
- uint64_t diff, pos = 0;
- char buf[FILE_IO_STACK_BUFFER_SIZE];
-
- assert(!stream->is_metadata);
-
- assert(stream->tracefile_size_current >
- stream->pos_after_last_complete_data_index);
- diff = stream->tracefile_size_current -
- stream->pos_after_last_complete_data_index;
-
- /* Create the new tracefile. */
- new_fd = utils_create_stream_file(stream->path_name,
- stream->channel_name,
- stream->tracefile_size, stream->tracefile_count,
- /* uid */ -1, /* gid */ -1, /* suffix */ NULL);
- if (new_fd < 0) {
- ERR("Failed to create new stream file at path %s for channel %s",
- stream->path_name, stream->channel_name);
- ret = -1;
- goto end;
- }
-
- /*
- * Rewind the current tracefile to the position at which the rotation
- * should have occurred.
- */
- lseek_ret = lseek(stream->stream_fd->fd,
- stream->pos_after_last_complete_data_index, SEEK_SET);
- if (lseek_ret < 0) {
- PERROR("seek truncate stream");
- ret = -1;
- goto end;
- }
-
- /* Move data from the old file to the new file. */
- while (pos < diff) {
- uint64_t count, bytes_left;
- ssize_t io_ret;
-
- bytes_left = diff - pos;
- count = bytes_left > sizeof(buf) ? sizeof(buf) : bytes_left;
- assert(count <= SIZE_MAX);
-
- io_ret = lttng_read(stream->stream_fd->fd, buf, count);
- if (io_ret < (ssize_t) count) {
- char error_string[256];
-
- snprintf(error_string, sizeof(error_string),
- "Failed to read %" PRIu64 " bytes from fd %i in rotate_truncate_stream(), returned %zi",
- count, stream->stream_fd->fd, io_ret);
- if (io_ret == -1) {
- PERROR("%s", error_string);
- } else {
- ERR("%s", error_string);
- }
- ret = -1;
- goto end;
- }
-
- io_ret = lttng_write(new_fd, buf, count);
- if (io_ret < (ssize_t) count) {
- char error_string[256];
-
- snprintf(error_string, sizeof(error_string),
- "Failed to write %" PRIu64 " bytes from fd %i in rotate_truncate_stream(), returned %zi",
- count, new_fd, io_ret);
- if (io_ret == -1) {
- PERROR("%s", error_string);
- } else {
- ERR("%s", error_string);
- }
- ret = -1;
- goto end;
- }
-
- pos += count;
- }
-
- /* Truncate the file to get rid of the excess data. */
- ret = ftruncate(stream->stream_fd->fd,
- stream->pos_after_last_complete_data_index);
- if (ret) {
- PERROR("ftruncate");
- goto end;
- }
-
- ret = close(stream->stream_fd->fd);
- if (ret < 0) {
- PERROR("Closing tracefile");
- goto end;
- }
-
- /*
- * Update the offset and FD of all the eventual indexes created by the
- * data connection before the rotation command arrived.
- */
- ret = relay_index_switch_all_files(stream);
- if (ret < 0) {
- ERR("Failed to rotate index file");
- goto end;
- }
-
- stream->stream_fd->fd = new_fd;
- stream->tracefile_size_current = diff;
- stream->pos_after_last_complete_data_index = 0;
- stream_complete_rotation(stream);
-
- ret = 0;
-
-end:
- return ret;
-}
-
static int stream_create_data_output_file_from_trace_chunk(
struct relay_stream *stream,
struct lttng_trace_chunk *trace_chunk,
return ret;
}
+/*
+ * If too much data has been written in a tracefile before we received the
+ * rotation command, we have to move the excess data to the new tracefile and
+ * perform the rotation. This can happen because the control and data
+ * connections are separate, the indexes as well as the commands arrive from
+ * the control connection and we have no control over the order so we could be
+ * in a situation where too much data has been received on the data connection
+ * before the rotation command on the control connection arrives.
+ */
+static int rotate_truncate_stream(struct relay_stream *stream)
+{
+ int ret;
+ off_t lseek_ret, previous_stream_copy_origin;
+ uint64_t copy_bytes_left, misplaced_data_size;
+ bool acquired_reference;
+ struct stream_fd *previous_stream_fd = NULL;
+ struct lttng_trace_chunk *previous_chunk = NULL;
+
+ ASSERT_LOCKED(stream->lock);
+ /*
+ * Acquire a reference to the current trace chunk to ensure
+ * it is not reclaimed when `stream_rotate_data_file` is called.
+ * Failing to do so would violate the contract of the trace
+ * chunk API as an active file descriptor would outlive the
+ * trace chunk.
+ */
+ acquired_reference = lttng_trace_chunk_get(stream->trace_chunk);
+ assert(acquired_reference);
+ previous_chunk = stream->trace_chunk;
+
+ /*
+ * Steal the stream's reference to its stream_fd. A new
+ * stream_fd will be created when the rotation completes and
+ * the orinal stream_fd will be used to copy the "extra" data
+ * to the new file.
+ */
+ assert(stream->stream_fd);
+ previous_stream_fd = stream->stream_fd;
+ stream->stream_fd = NULL;
+
+ assert(!stream->is_metadata);
+ assert(stream->tracefile_size_current >
+ stream->pos_after_last_complete_data_index);
+ misplaced_data_size = stream->tracefile_size_current -
+ stream->pos_after_last_complete_data_index;
+ copy_bytes_left = misplaced_data_size;
+ previous_stream_copy_origin = stream->pos_after_last_complete_data_index;
+
+ ret = stream_rotate_data_file(stream);
+ if (ret) {
+ goto end;
+ }
+
+ /*
+ * Seek the current tracefile to the position at which the rotation
+ * should have occurred.
+ */
+ lseek_ret = lseek(previous_stream_fd->fd, previous_stream_copy_origin,
+ SEEK_SET);
+ if (lseek_ret < 0) {
+ PERROR("Failed to seek to offset %" PRIu64
+ " while copying extra data received before a stream rotation",
+ (uint64_t) previous_stream_copy_origin);
+ ret = -1;
+ goto end;
+ }
+
+ /* Move data from the old file to the new file. */
+ while (copy_bytes_left) {
+ ssize_t io_ret;
+ char copy_buffer[FILE_IO_STACK_BUFFER_SIZE];
+ const off_t copy_size_this_pass = min_t(
+ off_t, copy_bytes_left, sizeof(copy_buffer));
+
+ io_ret = lttng_read(previous_stream_fd->fd, copy_buffer,
+ copy_size_this_pass);
+ if (io_ret < (ssize_t) copy_size_this_pass) {
+ if (io_ret == -1) {
+ PERROR("Failed to read %" PRIu64
+ " bytes from fd %i in %s(), returned %zi",
+ copy_size_this_pass,
+ previous_stream_fd->fd,
+ __FUNCTION__, io_ret);
+ } else {
+ ERR("Failed to read %" PRIu64
+ " bytes from fd %i in %s(), returned %zi",
+ copy_size_this_pass,
+ previous_stream_fd->fd,
+ __FUNCTION__, io_ret);
+ }
+ ret = -1;
+ goto end;
+ }
+
+ io_ret = lttng_write(stream->stream_fd->fd, copy_buffer,
+ copy_size_this_pass);
+ if (io_ret < (ssize_t) copy_size_this_pass) {
+ if (io_ret == -1) {
+ PERROR("Failed to write %" PRIu64
+ " bytes from fd %i in %s(), returned %zi",
+ copy_size_this_pass,
+ stream->stream_fd->fd,
+ __FUNCTION__, io_ret);
+ } else {
+ ERR("Failed to write %" PRIu64
+ " bytes from fd %i in %s(), returned %zi",
+ copy_size_this_pass,
+ stream->stream_fd->fd,
+ __FUNCTION__, io_ret);
+ }
+ ret = -1;
+ goto end;
+ }
+ copy_bytes_left -= copy_size_this_pass;
+ }
+
+ /* Truncate the file to get rid of the excess data. */
+ ret = ftruncate(previous_stream_fd->fd, previous_stream_copy_origin);
+ if (ret) {
+ PERROR("Failed to truncate current stream file to offset %" PRIu64,
+ previous_stream_copy_origin);
+ goto end;
+ }
+
+ /*
+ * Update the offset and FD of all the eventual indexes created by the
+ * data connection before the rotation command arrived.
+ */
+ ret = relay_index_switch_all_files(stream);
+ if (ret < 0) {
+ ERR("Failed to rotate index file");
+ goto end;
+ }
+
+ stream->tracefile_size_current = misplaced_data_size;
+ /* Index and data contents are back in sync. */
+ stream->pos_after_last_complete_data_index = 0;
+ ret = 0;
+end:
+ lttng_trace_chunk_put(previous_chunk);
+ stream_fd_put(previous_stream_fd);
+ return ret;
+}
+
/*
* Check if a stream's data file (as opposed to index) should be rotated
* (for session rotation).
projects / lttng-tools.git / commitdiff
