[PATCH v2 03/14] fsx: fixes to random seed
From: Amir Goldstein <amir73il@gmail.com>
Date: 2017-08-30 14:51:25
Also in:
fstests
Subsystem:
the rest · Maintainer:
Linus Torvalds
Not sure why, but with initstate()/setstate(), sfx generates
same events regadless of the input seed argument.
Change to use srandom() to fix the problem.
Add pid to auto random seed, so parallel fsx executions with auto
seed will use different seed values.
At this time there are 6 tests that use sfx, out of which:
2 use -S 0 as seed (gettime()) - generic/{075,112}
2 do not specify seed (default = 1) - generic/{091,263}
1 uses explicit constant seed - generic/127
1 uses explicit $RANDOM seed - generic/231
This change affects all those tests.
The tests that intended to randomize the seed will now really
randomize the seed.
The tests that intended to use a constant seed will still use
a constant seed, but resulting event sequence will be different
than before this change.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
ltp/fsx.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/ltp/fsx.c b/ltp/fsx.c
index 3713bbe..572df75 100644
--- a/ltp/fsx.c
+++ b/ltp/fsx.c@@ -116,7 +116,6 @@ int fd; /* fd for our test file */ blksize_t block_size = 0; off_t file_size = 0; off_t biggest = 0; -char state[256]; unsigned long testcalls = 0; /* calls to function "test" */ unsigned long simulatedopcount = 0; /* -b flag */
@@ -1909,8 +1908,10 @@ main(int argc, char **argv) break; case 'S': seed = getnum(optarg, &endp); - if (seed == 0) + if (seed == 0) { seed = time(0) % 10000; + seed += (int)getpid(); + } if (!quiet) fprintf(stdout, "Seed set to %d\n", seed); if (seed < 0)
@@ -1948,8 +1949,7 @@ main(int argc, char **argv) signal(SIGUSR1, cleanup); signal(SIGUSR2, cleanup); - initstate(seed, state, 256); - setstate(state); + srandom(seed); fd = open(fname, O_RDWR|(lite ? 0 : O_CREAT|O_TRUNC)|o_direct, 0666); if (fd < 0) {
--
2.7.4