In the shm-path mode, the metadata will be backuped to a metadata file, when run the lttng command "lttng metadata regenerate" to resample the wall time following a major NTP correction, the metadata file will not be truncated and regenerated.
Add the function ust_metadata_truncate() to truncate and regenerate the metadata file. Signed-off-by: Liguang Li <[email protected]> --- src/bin/lttng-sessiond/cmd.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c index 325ffd2..ba83226 100644 --- a/src/bin/lttng-sessiond/cmd.c +++ b/src/bin/lttng-sessiond/cmd.c @@ -3378,6 +3378,25 @@ end: } static +int ust_metadata_truncate(int fd, size_t length) +{ + int ret; + + ret = lseek(fd, length, SEEK_SET); + if (ret < 0) { + PERROR("lseek"); + goto out; + } + + ret = ftruncate(fd, length); + if (ret < 0) + PERROR("ftruncate"); + +out: + return ret; +} + +static int ust_regenerate_metadata(struct ltt_ust_session *usess) { int ret = 0; @@ -3398,6 +3417,15 @@ int ust_regenerate_metadata(struct ltt_ust_session *usess) memset(registry->metadata, 0, registry->metadata_alloc_len); registry->metadata_len = 0; registry->metadata_version++; + /*truncate the metadata file*/ + if (registry->metadata_fd > 0) { + ret = ust_metadata_truncate(registry->metadata_fd, 0); + if (ret) { + pthread_mutex_unlock(®istry->lock); + goto end; + } + } + ret = ust_metadata_session_statedump(registry, NULL, registry->major, registry->minor); if (ret) { -- 2.7.4 _______________________________________________ lttng-dev mailing list [email protected] https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
