if we run blktrace on same device twice, the second time will failed
to ioctl(BLKTRACESETUP), then it will call __stop_tracer, which lead
the first blktrace failed to access debugfs entries. So this patch add
a check to handle this case, to avoid stop tracer uncondionally.
Signed-off-by: weiping zhang <zhangweiping@xxxxxxxxxxxxxxx>
---
blktrace.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/blktrace.c b/blktrace.c
index e048f68..d0d271f 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -112,6 +112,7 @@ struct devpath {
struct cl_host *ch;
u32 cl_id;
time_t cl_connect_time;
+ int setup_done; /* ioctl BLKTRACESETUP done */
struct io_info *ios;
};
@@ -1083,6 +1084,7 @@ static int setup_buts(void)
if (ioctl(dpp->fd, BLKTRACESETUP, &buts) >= 0) {
dpp->ncpus = max_cpus;
dpp->buts_name = strdup(buts.name);
+ dpp->setup_done = 1;
if (dpp->stats)
free(dpp->stats);
dpp->stats = calloc(dpp->ncpus, sizeof(*dpp->stats));
@@ -1285,7 +1287,8 @@ static void rel_devpaths(void)
struct devpath *dpp = list_entry(p, struct devpath, head);
list_del(&dpp->head);
- __stop_trace(dpp->fd);
+ if (dpp->setup_done)
+ __stop_trace(dpp->fd);
close(dpp->fd);
if (dpp->heads)
--
1.8.3.1
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