From: Jens Axboe <axboe@fb.com>
Date: Sat, 30 May 2015 01:40:21 +0000 (-0600)
Subject: filesetup: print warning if chosen random generator can't cover range
X-Git-Tag: fio-2.2.9~26
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=37fbd7e9dd4f041b858507b3db06753614083770

filesetup: print warning if chosen random generator can't cover range

If the file or device is huge, we could have an issue with the
default 32-bit random offset generator in that it wont cover
the entire device. If fio detects this and the random generator
wasn't explicitly set, then log an error and exit.

Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/filesetup.c b/filesetup.c
index f4324e23..51efdf76 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -1067,6 +1067,16 @@ int init_random_map(struct thread_data *td)
 
 		blocks = fsize / (unsigned long long) td->o.rw_min_bs;
 
+		if (blocks > FRAND32_MAX &&
+		    td->o.random_generator == FIO_RAND_GEN_TAUSWORTHE &&
+		    !fio_option_is_set(&td->o, random_generator)) {
+			log_err("fio: file %s exceeds 32-bit tausworthe "
+				 "random generator. Use lfsr or "
+				 "tausworthe64.\n", f->file_name);
+			td_verror(td, EINVAL, "init file random");
+			return 1;
+		}
+
 		if (td->o.random_generator == FIO_RAND_GEN_LFSR) {
 			unsigned long seed;