Commit a7fa94a9 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by Artem Bityutskiy
Browse files

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: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent d27462a5

fs/ubifs/debug.c

+50 −41
Original line number Diff line number Diff line
@@ -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 @@ error_dump: 
	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 @@ static int power_cut_emulated(struct ubifs_info *c, int lnum, int write) 
	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))

		if (write && chance(1, 2))

			return 0;

		} else if (chance(19, 20))

		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 @@ static int power_cut_emulated(struct ubifs_info *c, int lnum, int write) 
			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))

		if (write && chance(99, 100))

			return 0;

		} else if (chance(399, 400))

		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))

		if (write && chance(7, 8))

			return 0;

		} else if (chance(19, 20))

		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))

		if (write && chance(1, 2))

			return 0;

		} else if (chance(9, 10))

		if (chance(9, 10))

			return 0;

		ubifs_warn("failing in orphan LEB %d", lnum);

	} else if (lnum == c->ihead_lnum) {
@@ -2636,18 +2631,32 @@ static int power_cut_emulated(struct ubifs_info *c, int lnum, int write) 
	}



	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,

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