iolog: fix potential div-by-zero

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

diff --git a/iolog.c b/iolog.c
index b0122bed78b10de59d76d07cbaccb0fe1f0a9513..07692fb25b05124482c3c781ec39829b4332ee9f 100644 (file)
--- a/iolog.c
+++ b/iolog.c
@@ -370,15 +370,21 @@ static bool read_iolog2(struct thread_data *td)
                        struct timespec now;
                        uint64_t elapsed;
                        uint64_t for_1s;
+
                        fio_gettime(&now, NULL);
                        elapsed = ntime_since(&td->io_log_highmark_time, &now);
-                       for_1s = (td->io_log_highmark - td->io_log_current) * 1000000000 / elapsed;
-                       items_to_fetch = for_1s - td->io_log_current;
+                       if (elapsed) {
+                               for_1s = (td->io_log_highmark - td->io_log_current) * 1000000000 / elapsed;
+                               items_to_fetch = for_1s - td->io_log_current;
+                       } else
+                               items_to_fetch = 0;
                        if (items_to_fetch < 0)
                                items_to_fetch = 0;
+
                        td->io_log_highmark = td->io_log_current + items_to_fetch;
                        td->io_log_checkmark = (td->io_log_highmark + 1) / 2;
                        fio_gettime(&td->io_log_highmark_time, NULL);
+
                        if (items_to_fetch == 0)
                                return true;
                }