[patch 5/7] fault-injection capability for disk IO

Akinobu Mita
2006-10-12T07:44:00Z

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From: Akinobu Mita <akinobu.mita@gmail.com>

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: Akinobu Mita <akinobu.mita@gmail.com>

block/genhd.c | 31 +++++++++++++++++++++++++++++++
block/ll_rw_blk.c | 43 +++++++++++++++++++++++++++++++++++++++++++
fs/partitions/check.c | 27 +++++++++++++++++++++++++++
include/linux/genhd.h | 4 ++++
lib/Kconfig.debug | 7 +++++++
5 files changed, 112 insertions(+)

Index: work-fault-inject/block/ll_rw_blk.c
===================================================================
--- work-fault-inject.orig/block/ll_rw_blk.c
+++ work-fault-inject/block/ll_rw_blk.c
@@ -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
@@ -3050,6 +3051,45 @@ static void handle_bad_sector(struct bio
set_bit(BIO_EOF, &bio->bi_flags);
}

+#ifdef CONFIG_FAIL_MAKE_REQUEST
+
+static DEFINE_FAULT_ATTR(fail_make_request);
+
+static int __init setup_fail_make_request(char *str)
+{
+ should_fail_srandom(jiffies);
+
+ 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)
+{
+ should_fail_srandom(jiffies);
+
+ return init_fault_attr_entries(&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.
@@ -3134,6 +3174,9 @@ end_io:
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.
Index: work-fault-inject/lib/Kconfig.debug
===================================================================
--- work-fault-inject.orig/lib/Kconfig.debug
+++ work-fault-inject/lib/Kconfig.debug
@@ -487,6 +487,13 @@ 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
Index: work-fault-inject/block/genhd.c
===================================================================
--- work-fault-inject.orig/block/genhd.c
+++ work-fault-inject/block/genhd.c
@@ -417,6 +417,34 @@ static struct disk_attribute disk_attr_s
.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,
};

Index: work-fault-inject/include/linux/genhd.h
===================================================================
--- work-fault-inject.orig/include/linux/genhd.h
+++ work-fault-inject/include/linux/genhd.h
@@ -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 */
Index: work-fault-inject/fs/partitions/check.c
===================================================================
--- work-fault-inject.orig/fs/partitions/check.c
+++ work-fault-inject/fs/partitions/check.c
@@ -276,12 +276,39 @@ static struct part_attribute part_attr_s
.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,
};

--