Commit c17bb495 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
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[PATCH] fault-injection capability for disk IO 



This patch provides fault-injection capability for disk IO.

Boot option:

fail_make_request=<probability>,<interval>,<space>,<times>

	<interval> -- specifies the interval of failures.

	<probability> -- specifies how often it should fail in percent.

	<space> -- specifies the size of free space where disk IO can be issued
		   safely in bytes.

	<times> -- specifies how many times failures may happen at most.

Debugfs:

/debug/fail_make_request/interval
/debug/fail_make_request/probability
/debug/fail_make_request/specifies
/debug/fail_make_request/times

Example:

	fail_make_request=10,100,0,-1
	echo 1 > /sys/blocks/hda/hda1/make-it-fail

generic_make_request() on /dev/hda1 fails once per 10 times.

Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 933e312e

block/genhd.c

+31 −0
Original line number Diff line number Diff line
@@ -417,6 +417,34 @@ static struct disk_attribute disk_attr_stat = { 
	.show	= disk_stats_read

};



#ifdef CONFIG_FAIL_MAKE_REQUEST



static ssize_t disk_fail_store(struct gendisk * disk,

			       const char *buf, size_t count)

{

	int i;



	if (count > 0 && sscanf(buf, "%d", &i) > 0) {

		if (i == 0)

			disk->flags &= ~GENHD_FL_FAIL;

		else

			disk->flags |= GENHD_FL_FAIL;

	}



	return count;

}

static ssize_t disk_fail_read(struct gendisk * disk, char *page)

{

	return sprintf(page, "%d\n", disk->flags & GENHD_FL_FAIL ? 1 : 0);

}

static struct disk_attribute disk_attr_fail = {

	.attr = {.name = "make-it-fail", .mode = S_IRUGO | S_IWUSR },

	.store	= disk_fail_store,

	.show	= disk_fail_read

};



#endif



static struct attribute * default_attrs[] = {

	&disk_attr_uevent.attr,

	&disk_attr_dev.attr,
@@ -424,6 +452,9 @@ static struct attribute * default_attrs[] = { 
	&disk_attr_removable.attr,

	&disk_attr_size.attr,

	&disk_attr_stat.attr,

#ifdef CONFIG_FAIL_MAKE_REQUEST

	&disk_attr_fail.attr,

#endif

	NULL,

};

block/ll_rw_blk.c

+40 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/interrupt.h>

#include <linux/cpu.h>

#include <linux/blktrace_api.h>

#include <linux/fault-inject.h>



/*

 * for max sense size
@@ -3056,6 +3057,42 @@ static void handle_bad_sector(struct bio *bio) 
	set_bit(BIO_EOF, &bio->bi_flags);

}



#ifdef CONFIG_FAIL_MAKE_REQUEST



static DECLARE_FAULT_ATTR(fail_make_request);



static int __init setup_fail_make_request(char *str)

{

	return setup_fault_attr(&fail_make_request, str);

}

__setup("fail_make_request=", setup_fail_make_request);



static int should_fail_request(struct bio *bio)

{

	if ((bio->bi_bdev->bd_disk->flags & GENHD_FL_FAIL) ||

	    (bio->bi_bdev->bd_part && bio->bi_bdev->bd_part->make_it_fail))

		return should_fail(&fail_make_request, bio->bi_size);



	return 0;

}



static int __init fail_make_request_debugfs(void)

{

	return init_fault_attr_dentries(&fail_make_request,

					"fail_make_request");

}



late_initcall(fail_make_request_debugfs);



#else /* CONFIG_FAIL_MAKE_REQUEST */



static inline int should_fail_request(struct bio *bio)

{

	return 0;

}



#endif /* CONFIG_FAIL_MAKE_REQUEST */



/**

 * generic_make_request: hand a buffer to its device driver for I/O

 * @bio:  The bio describing the location in memory and on the device.
@@ -3141,6 +3178,9 @@ void generic_make_request(struct bio *bio) 
		if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))

			goto end_io;



		if (should_fail_request(bio))

			goto end_io;



		/*

		 * If this device has partitions, remap block n

		 * of partition p to block n+start(p) of the disk.

fs/partitions/check.c

+27 −0
Original line number Diff line number Diff line
@@ -276,12 +276,39 @@ static struct part_attribute part_attr_stat = { 
	.show	= part_stat_read

};



#ifdef CONFIG_FAIL_MAKE_REQUEST



static ssize_t part_fail_store(struct hd_struct * p,

			       const char *buf, size_t count)

{

	int i;



	if (count > 0 && sscanf(buf, "%d", &i) > 0)

		p->make_it_fail = (i == 0) ? 0 : 1;



	return count;

}

static ssize_t part_fail_read(struct hd_struct * p, char *page)

{

	return sprintf(page, "%d\n", p->make_it_fail);

}

static struct part_attribute part_attr_fail = {

	.attr = {.name = "make-it-fail", .mode = S_IRUGO | S_IWUSR },

	.store	= part_fail_store,

	.show	= part_fail_read

};



#endif



static struct attribute * default_attrs[] = {

	&part_attr_uevent.attr,

	&part_attr_dev.attr,

	&part_attr_start.attr,

	&part_attr_size.attr,

	&part_attr_stat.attr,

#ifdef CONFIG_FAIL_MAKE_REQUEST

	&part_attr_fail.attr,

#endif

	NULL,

};

include/linux/genhd.h

+4 −0
Original line number Diff line number Diff line
@@ -83,6 +83,9 @@ struct hd_struct { 
	struct kobject *holder_dir;

	unsigned ios[2], sectors[2];	/* READs and WRITEs */

	int policy, partno;

#ifdef CONFIG_FAIL_MAKE_REQUEST

	int make_it_fail;

#endif

};



#define GENHD_FL_REMOVABLE			1
@@ -90,6 +93,7 @@ struct hd_struct { 
#define GENHD_FL_CD				8

#define GENHD_FL_UP				16

#define GENHD_FL_SUPPRESS_PARTITION_INFO	32

#define GENHD_FL_FAIL				64



struct disk_stats {

	unsigned long sectors[2];	/* READs and WRITEs */

lib/Kconfig.debug

+7 −0
Original line number Diff line number Diff line
@@ -431,6 +431,13 @@ config FAIL_PAGE_ALLOC 
	help

	  This option provides fault-injection capabilitiy for alloc_pages().



config FAIL_MAKE_REQUEST

	bool "Fault-injection capabilitiy for disk IO"

	depends on DEBUG_KERNEL

	select FAULT_INJECTION

	help

	  This option provides fault-injection capabilitiy to disk IO.



config FAULT_INJECTION_DEBUG_FS

	bool "Debugfs entries for fault-injection capabilities"

	depends on FAULT_INJECTION && SYSFS