[patch 4/5] fail-injection capability for disk IO

Akinobu Mita
2006-08-23T11:35:38Z

[-- Attachment #1: fail_make_request.patch --]
[-- Type: text/plain, Size: 3049 bytes --]

This patch provides fail-injection capability for disk IO.

Boot option:

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

<probability>

specifies how often it should fail in percent.

<interval>

specifies the interval of failures.

<times>

specifies how many times failures may happen at most.

<space>

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

Example:

fail_make_request=100,10,-1,0

generic_make_request() fails once per 10 times.

Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>

block/ll_rw_blk.c | 19 +++++++++++++++++++
include/linux/should_fail.h | 4 ++++
lib/Kconfig.debug | 7 +++++++
3 files changed, 30 insertions(+)

Index: work-failmalloc/block/ll_rw_blk.c
===================================================================
--- work-failmalloc.orig/block/ll_rw_blk.c
+++ work-failmalloc/block/ll_rw_blk.c
@@ -28,6 +28,7 @@
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/blktrace_api.h>
+#include <linux/should_fail.h>

/*
* for max sense size
@@ -2993,6 +2994,21 @@ static void handle_bad_sector(struct bio
set_bit(BIO_EOF, &bio->bi_flags);
}

+#ifdef CONFIG_FAIL_MAKE_REQUEST
+
+static DEFINE_SHOULD_FAIL(fail_make_request_data);
+
+static int __init setup_fail_make_request(char *str)
+{
+ return setup_should_fail(&fail_make_request_data, str);
+}
+__setup("fail_make_request=", setup_fail_make_request);
+
+struct should_fail_data *fail_make_request = &fail_make_request_data;
+EXPORT_SYMBOL_GPL(fail_make_request);
+
+#endif
+
/**
* 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.
@@ -3077,6 +3093,9 @@ end_io:
if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
goto end_io;

+ if (should_fail(fail_make_request, bio->bi_size))
+ goto end_io;
+
/*
* If this device has partitions, remap block n
* of partition p to block n+start(p) of the disk.
Index: work-failmalloc/lib/Kconfig.debug
===================================================================
--- work-failmalloc.orig/lib/Kconfig.debug
+++ work-failmalloc/lib/Kconfig.debug
@@ -386,3 +386,10 @@ 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 SHOULD_FAIL
+ help
+ This option provides fault-injection capabilitiy to disk IO.
+
Index: work-failmalloc/include/linux/should_fail.h
===================================================================
--- work-failmalloc.orig/include/linux/should_fail.h
+++ work-failmalloc/include/linux/should_fail.h
@@ -43,6 +43,10 @@ extern struct should_fail_data *failslab
extern struct should_fail_data *fail_page_alloc;
#endif

+#ifdef CONFIG_FAIL_MAKE_REQUEST
+extern struct should_fail_data *fail_make_request;
+#endif
+
#else

#define should_fail(data, size) (0)

--