blktrace: abort if device ioctl setup fails

If we fail doing the BLKTRACESETUP ioctl, blktrace still marches on
and sets up the rest. This results in errors like the below:

blktrace /dev/sdf
BLKTRACESETUP(2) /dev/sdf failed: 5/Input/output error
Thread 1 failed open /sys/kernel/debug/block/(null)/trace1: 2/No such file or directory
Thread 3 failed open /sys/kernel/debug/block/(null)/trace3: 2/No such file or directory
Thread 2 failed open /sys/kernel/debug/block/(null)/trace2: 2/No such file or directory
[...]
FAILED to start thread on CPU 0: 1/Operation not permitted
FAILED to start thread on CPU 1: 1/Operation not permitted
FAILED to start thread on CPU 2: 1/Operation not permitted

and blktrace continues to run, though it can't do anything in this
state.

If the ioctl setup fails, just abort.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 9 insertions, 3 deletions

diff --git a/blktrace.c b/blktrace.c
index e8f2f87..e048f68 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -1066,9 +1066,10 @@ static void close_client_connections(void)
 	}
 }
 
-static void setup_buts(void)
+static int setup_buts(void)
 {
 	struct list_head *p;
+	int ret = 0;
 
 	__list_for_each(p, &devpaths) {
 		struct blk_user_trace_setup buts;
@@ -1086,10 +1087,14 @@ static void setup_buts(void)
 				free(dpp->stats);
 			dpp->stats = calloc(dpp->ncpus, sizeof(*dpp->stats));
 			memset(dpp->stats, 0, dpp->ncpus * sizeof(*dpp->stats));
-		} else
+		} else {
 			fprintf(stderr, "BLKTRACESETUP(2) %s failed: %d/%s\n",
 				dpp->path, errno, strerror(errno));
+			ret++;
+		}
 	}
+
+	return ret;
 }
 
 static void start_buts(void)
@@ -2676,7 +2681,8 @@ static int run_tracers(void)
 	if (net_mode == Net_client)
 		printf("blktrace: connecting to %s\n", hostname);
 
-	setup_buts();
+	if (setup_buts())
+		return 1;
 
 	if (use_tracer_devpaths()) {
 		if (setup_tracer_devpaths())