From f4c12f116d328c0b56eabac327a9cc4882c57128 Mon Sep 17 00:00:00 2001
From: Austin Clements <amdragon@mit.edu>
Date: Mon, 23 Nov 2009 17:27:26 -0500
Subject: [PATCH] Add the test we used in lecture to creash the IDE system when
the locks were moved around.
---
Makefile | 1 +
stressfs.c | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
create mode 100644 stressfs.c
diff --git a/Makefile b/Makefile
index 24ba05e..3cab47a 100644
--- a/Makefile
+++ b/Makefile
@@ -107,6 +107,7 @@ UPROGS=\
_mkdir\
_rm\
_sh\
+ _stressfs\
_usertests\
_wc\
_zombie\
diff --git a/stressfs.c b/stressfs.c
new file mode 100644
index 0000000..21a5d16
--- /dev/null
+++ b/stressfs.c
@@ -0,0 +1,38 @@
+// Demonstrate that moving the "acquire" in iderw after the loop that
+// appends to the idequeue results in a race.
+
+// For this to work, you should also add a spin within iderw's
+// idequeue traversal loop. Spinning 40000 times demonstrated the bug
+// after about 5 runs of stressfs in QEMU on a 2.1GHz CPU.
+
+#include "types.h"
+#include "stat.h"
+#include "user.h"
+#include "fs.h"
+#include "fcntl.h"
+
+int
+main(int argc, char *argv[])
+{
+ int i;
+ printf(1, "stressfs starting\n");
+
+ for (i = 0; i < 4; i++) {
+ if (fork() > 0) {
+ break;
+ }
+ }
+
+ printf(1, "%d\n", i);
+
+ char path[] = "stressfs0";
+ path[8] += i;
+ int fd = open(path, O_CREATE | O_RDWR);
+ for (i = 0; i < 100; i++)
+ printf(fd, "%d\n", i);
+ close(fd);
+
+ wait();
+
+ exit();
+}
--
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