From c17bb4951752d3e0f49cd1ea9d2e868422f9e0d6 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Fri, 8 Dec 2006 02:39:46 -0800 Subject: [PATCH] fault-injection capability for disk IO This patch provides fault-injection capability for disk IO. Boot option: fail_make_request=,,, -- specifies the interval of failures. -- specifies how often it should fail in percent. -- specifies the size of free space where disk IO can be issued safely in bytes. -- 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 Signed-off-by: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- block/genhd.c | 31 +++++++++++++++++++++++++++++++ block/ll_rw_blk.c | 40 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 71 insertions(+) (limited to 'block') diff --git a/block/genhd.c b/block/genhd.c index 653919d50cd..457fdac4c17 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -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, }; diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index 31512cd9f3a..4f83fd92237 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -28,6 +28,7 @@ #include #include #include +#include /* * 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 @@ 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. -- cgit v1.2.3-70-g09d2