From: Akinobu Mita 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 block/genhd.c | 31 +++++++++++++++++++++++++++++++ block/ll_rw_blk.c | 40 ++++++++++++++++++++++++++++++++++++++++ fs/partitions/check.c | 27 +++++++++++++++++++++++++++ include/linux/genhd.h | 4 ++++ lib/Kconfig.debug | 7 +++++++ 5 files changed, 109 insertions(+) Index: 2.6-rc/block/ll_rw_blk.c =================================================================== --- 2.6-rc.orig/block/ll_rw_blk.c +++ 2.6-rc/block/ll_rw_blk.c @@ -28,6 +28,7 @@ #include #include #include +#include /* * for max sense size @@ -2971,6 +2972,42 @@ static void handle_bad_sector(struct 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. @@ -3056,6 +3093,9 @@ 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: 2.6-rc/lib/Kconfig.debug =================================================================== --- 2.6-rc.orig/lib/Kconfig.debug +++ 2.6-rc/lib/Kconfig.debug @@ -430,6 +430,13 @@ 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: 2.6-rc/block/genhd.c =================================================================== --- 2.6-rc.orig/block/genhd.c +++ 2.6-rc/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: 2.6-rc/include/linux/genhd.h =================================================================== --- 2.6-rc.orig/include/linux/genhd.h +++ 2.6-rc/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: 2.6-rc/fs/partitions/check.c =================================================================== --- 2.6-rc.orig/fs/partitions/check.c +++ 2.6-rc/fs/partitions/check.c @@ -265,12 +265,39 @@ 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, }; -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/