UBIFS: improve power cut emulation testing
This patch cleans-up and improves the power cut testing:
1. Kill custom 'simple_random()' function and use 'random32()' instead.
2. Make timeout larger
3. When cutting the buffer - fill the end with random data sometimes, not
only with 0xFFs.
4. Some times cut in the middle of the buffer, not always at the end.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index b801af7..eef109a 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -27,11 +27,12 @@
* various local functions of those subsystems.
*/
-#include "ubifs.h"
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/math64.h>
#include <linux/uaccess.h>
+#include <linux/random.h>
+#include "ubifs.h"
#ifdef CONFIG_UBIFS_FS_DEBUG
@@ -2535,17 +2536,10 @@
return 0;
}
-/* Failure mode for recovery testing */
-
-#define chance(n, d) (simple_rand() <= (n) * 32768LL / (d))
-
-static unsigned int next;
-static int simple_rand(void)
+static inline int chance(unsigned int n, unsigned int out_of)
{
- if (next == 0)
- next = current->pid;
- next = next * 1103515245 + 12345;
- return (next >> 16) & 32767;
+ return !!((random32() % out_of) + 1 <= n);
+
}
static int power_cut_emulated(struct ubifs_info *c, int lnum, int write)
@@ -2557,33 +2551,37 @@
if (!d->pc_cnt) {
/* First call - decide delay to the power cut */
if (chance(1, 2)) {
- unsigned int delay = 1 << (simple_rand() >> 11);
+ unsigned long delay;
if (chance(1, 2)) {
d->pc_delay = 1;
- d->pc_timeout = jiffies +
- msecs_to_jiffies(delay);
- ubifs_warn("failing after %ums", delay);
+ /* Fail withing 1 minute */
+ delay = random32() % 60000;
+ d->pc_timeout = jiffies;
+ d->pc_timeout += msecs_to_jiffies(delay);
+ ubifs_warn("failing after %lums", delay);
} else {
d->pc_delay = 2;
+ delay = random32() % 10000;
+ /* Fail within 10000 operations */
d->pc_cnt_max = delay;
- ubifs_warn("failing after %u calls", delay);
+ ubifs_warn("failing after %lu calls", delay);
}
}
+
d->pc_cnt += 1;
}
+
/* Determine if failure delay has expired */
- if (d->pc_delay == 1) {
- if (time_before(jiffies, d->pc_timeout))
+ if (d->pc_delay == 1 && time_before(jiffies, d->pc_timeout))
return 0;
- } else if (d->pc_delay == 2)
- if (d->pc_cnt++ < d->pc_cnt_max)
+ if (d->pc_delay == 2 && d->pc_cnt++ < d->pc_cnt_max)
return 0;
+
if (lnum == UBIFS_SB_LNUM) {
- if (write) {
- if (chance(1, 2))
- return 0;
- } else if (chance(19, 20))
+ if (write && chance(1, 2))
+ return 0;
+ if (chance(19, 20))
return 0;
ubifs_warn("failing in super block LEB %d", lnum);
} else if (lnum == UBIFS_MST_LNUM || lnum == UBIFS_MST_LNUM + 1) {
@@ -2591,24 +2589,21 @@
return 0;
ubifs_warn("failing in master LEB %d", lnum);
} else if (lnum >= UBIFS_LOG_LNUM && lnum <= c->log_last) {
- if (write) {
- if (chance(99, 100))
- return 0;
- } else if (chance(399, 400))
+ if (write && chance(99, 100))
+ return 0;
+ if (chance(399, 400))
return 0;
ubifs_warn("failing in log LEB %d", lnum);
} else if (lnum >= c->lpt_first && lnum <= c->lpt_last) {
- if (write) {
- if (chance(7, 8))
- return 0;
- } else if (chance(19, 20))
+ if (write && chance(7, 8))
+ return 0;
+ if (chance(19, 20))
return 0;
ubifs_warn("failing in LPT LEB %d", lnum);
} else if (lnum >= c->orph_first && lnum <= c->orph_last) {
- if (write) {
- if (chance(1, 2))
- return 0;
- } else if (chance(9, 10))
+ if (write && chance(1, 2))
+ return 0;
+ if (chance(9, 10))
return 0;
ubifs_warn("failing in orphan LEB %d", lnum);
} else if (lnum == c->ihead_lnum) {
@@ -2636,18 +2631,32 @@
}
d->pc_happened = 1;
+ ubifs_warn("========== Power cut emulated ==========");
dump_stack();
return 1;
}
-static void cut_data(const void *buf, int len)
+static void cut_data(const void *buf, unsigned int len)
{
- int flen, i;
+ unsigned int from, to, i, ffs = chance(1, 2);
unsigned char *p = (void *)buf;
- flen = (len * (long long)simple_rand()) >> 15;
- for (i = flen; i < len; i++)
- p[i] = 0xff;
+ from = random32() % (len + 1);
+ if (chance(1, 2))
+ to = random32() % (len - from + 1);
+ else
+ to = len;
+
+ if (from < to)
+ ubifs_warn("filled bytes %u-%u with %s", from, to - 1,
+ ffs ? "0xFFs" : "random data");
+
+ if (ffs)
+ for (i = from; i < to; i++)
+ p[i] = 0xFF;
+ else
+ for (i = from; i < to; i++)
+ p[i] = random32() % 0x100;
}
int dbg_leb_write(struct ubifs_info *c, int lnum, const void *buf,