364 lines
8.6 KiB
C
364 lines
8.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* faulty.c : Multiple Devices driver for Linux
|
|
*
|
|
* Copyright (C) 2004 Neil Brown
|
|
*
|
|
* fautly-device-simulator personality for md
|
|
*/
|
|
|
|
|
|
/*
|
|
* The "faulty" personality causes some requests to fail.
|
|
*
|
|
* Possible failure modes are:
|
|
* reads fail "randomly" but succeed on retry
|
|
* writes fail "randomly" but succeed on retry
|
|
* reads for some address fail and then persist until a write
|
|
* reads for some address fail and then persist irrespective of write
|
|
* writes for some address fail and persist
|
|
* all writes fail
|
|
*
|
|
* Different modes can be active at a time, but only
|
|
* one can be set at array creation. Others can be added later.
|
|
* A mode can be one-shot or recurrent with the recurrence being
|
|
* once in every N requests.
|
|
* The bottom 5 bits of the "layout" indicate the mode. The
|
|
* remainder indicate a period, or 0 for one-shot.
|
|
*
|
|
* There is an implementation limit on the number of concurrently
|
|
* persisting-faulty blocks. When a new fault is requested that would
|
|
* exceed the limit, it is ignored.
|
|
* All current faults can be clear using a layout of "0".
|
|
*
|
|
* Requests are always sent to the device. If they are to fail,
|
|
* we clone the bio and insert a new b_end_io into the chain.
|
|
*/
|
|
|
|
#define WriteTransient 0
|
|
#define ReadTransient 1
|
|
#define WritePersistent 2
|
|
#define ReadPersistent 3
|
|
#define WriteAll 4 /* doesn't go to device */
|
|
#define ReadFixable 5
|
|
#define Modes 6
|
|
|
|
#define ClearErrors 31
|
|
#define ClearFaults 30
|
|
|
|
#define AllPersist 100 /* internal use only */
|
|
#define NoPersist 101
|
|
|
|
#define ModeMask 0x1f
|
|
#define ModeShift 5
|
|
|
|
#define MaxFault 50
|
|
#include <linux/blkdev.h>
|
|
#include <linux/module.h>
|
|
#include <linux/raid/md_u.h>
|
|
#include <linux/slab.h>
|
|
#include "md.h"
|
|
#include <linux/seq_file.h>
|
|
|
|
|
|
static void faulty_fail(struct bio *bio)
|
|
{
|
|
struct bio *b = bio->bi_private;
|
|
|
|
b->bi_iter.bi_size = bio->bi_iter.bi_size;
|
|
b->bi_iter.bi_sector = bio->bi_iter.bi_sector;
|
|
|
|
bio_put(bio);
|
|
|
|
bio_io_error(b);
|
|
}
|
|
|
|
struct faulty_conf {
|
|
int period[Modes];
|
|
atomic_t counters[Modes];
|
|
sector_t faults[MaxFault];
|
|
int modes[MaxFault];
|
|
int nfaults;
|
|
struct md_rdev *rdev;
|
|
};
|
|
|
|
static int check_mode(struct faulty_conf *conf, int mode)
|
|
{
|
|
if (conf->period[mode] == 0 &&
|
|
atomic_read(&conf->counters[mode]) <= 0)
|
|
return 0; /* no failure, no decrement */
|
|
|
|
|
|
if (atomic_dec_and_test(&conf->counters[mode])) {
|
|
if (conf->period[mode])
|
|
atomic_set(&conf->counters[mode], conf->period[mode]);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int check_sector(struct faulty_conf *conf, sector_t start, sector_t end, int dir)
|
|
{
|
|
/* If we find a ReadFixable sector, we fix it ... */
|
|
int i;
|
|
for (i=0; i<conf->nfaults; i++)
|
|
if (conf->faults[i] >= start &&
|
|
conf->faults[i] < end) {
|
|
/* found it ... */
|
|
switch (conf->modes[i] * 2 + dir) {
|
|
case WritePersistent*2+WRITE: return 1;
|
|
case ReadPersistent*2+READ: return 1;
|
|
case ReadFixable*2+READ: return 1;
|
|
case ReadFixable*2+WRITE:
|
|
conf->modes[i] = NoPersist;
|
|
return 0;
|
|
case AllPersist*2+READ:
|
|
case AllPersist*2+WRITE: return 1;
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void add_sector(struct faulty_conf *conf, sector_t start, int mode)
|
|
{
|
|
int i;
|
|
int n = conf->nfaults;
|
|
for (i=0; i<conf->nfaults; i++)
|
|
if (conf->faults[i] == start) {
|
|
switch(mode) {
|
|
case NoPersist: conf->modes[i] = mode; return;
|
|
case WritePersistent:
|
|
if (conf->modes[i] == ReadPersistent ||
|
|
conf->modes[i] == ReadFixable)
|
|
conf->modes[i] = AllPersist;
|
|
else
|
|
conf->modes[i] = WritePersistent;
|
|
return;
|
|
case ReadPersistent:
|
|
if (conf->modes[i] == WritePersistent)
|
|
conf->modes[i] = AllPersist;
|
|
else
|
|
conf->modes[i] = ReadPersistent;
|
|
return;
|
|
case ReadFixable:
|
|
if (conf->modes[i] == WritePersistent ||
|
|
conf->modes[i] == ReadPersistent)
|
|
conf->modes[i] = AllPersist;
|
|
else
|
|
conf->modes[i] = ReadFixable;
|
|
return;
|
|
}
|
|
} else if (conf->modes[i] == NoPersist)
|
|
n = i;
|
|
|
|
if (n >= MaxFault)
|
|
return;
|
|
conf->faults[n] = start;
|
|
conf->modes[n] = mode;
|
|
if (conf->nfaults == n)
|
|
conf->nfaults = n+1;
|
|
}
|
|
|
|
static bool faulty_make_request(struct mddev *mddev, struct bio *bio)
|
|
{
|
|
struct faulty_conf *conf = mddev->private;
|
|
int failit = 0;
|
|
|
|
if (bio_data_dir(bio) == WRITE) {
|
|
/* write request */
|
|
if (atomic_read(&conf->counters[WriteAll])) {
|
|
/* special case - don't decrement, don't generic_make_request,
|
|
* just fail immediately
|
|
*/
|
|
bio_io_error(bio);
|
|
return true;
|
|
}
|
|
|
|
if (check_sector(conf, bio->bi_iter.bi_sector,
|
|
bio_end_sector(bio), WRITE))
|
|
failit = 1;
|
|
if (check_mode(conf, WritePersistent)) {
|
|
add_sector(conf, bio->bi_iter.bi_sector,
|
|
WritePersistent);
|
|
failit = 1;
|
|
}
|
|
if (check_mode(conf, WriteTransient))
|
|
failit = 1;
|
|
} else {
|
|
/* read request */
|
|
if (check_sector(conf, bio->bi_iter.bi_sector,
|
|
bio_end_sector(bio), READ))
|
|
failit = 1;
|
|
if (check_mode(conf, ReadTransient))
|
|
failit = 1;
|
|
if (check_mode(conf, ReadPersistent)) {
|
|
add_sector(conf, bio->bi_iter.bi_sector,
|
|
ReadPersistent);
|
|
failit = 1;
|
|
}
|
|
if (check_mode(conf, ReadFixable)) {
|
|
add_sector(conf, bio->bi_iter.bi_sector,
|
|
ReadFixable);
|
|
failit = 1;
|
|
}
|
|
}
|
|
if (failit) {
|
|
struct bio *b = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
|
|
|
|
bio_set_dev(b, conf->rdev->bdev);
|
|
b->bi_private = bio;
|
|
b->bi_end_io = faulty_fail;
|
|
bio = b;
|
|
} else
|
|
bio_set_dev(bio, conf->rdev->bdev);
|
|
|
|
generic_make_request(bio);
|
|
return true;
|
|
}
|
|
|
|
static void faulty_status(struct seq_file *seq, struct mddev *mddev)
|
|
{
|
|
struct faulty_conf *conf = mddev->private;
|
|
int n;
|
|
|
|
if ((n=atomic_read(&conf->counters[WriteTransient])) != 0)
|
|
seq_printf(seq, " WriteTransient=%d(%d)",
|
|
n, conf->period[WriteTransient]);
|
|
|
|
if ((n=atomic_read(&conf->counters[ReadTransient])) != 0)
|
|
seq_printf(seq, " ReadTransient=%d(%d)",
|
|
n, conf->period[ReadTransient]);
|
|
|
|
if ((n=atomic_read(&conf->counters[WritePersistent])) != 0)
|
|
seq_printf(seq, " WritePersistent=%d(%d)",
|
|
n, conf->period[WritePersistent]);
|
|
|
|
if ((n=atomic_read(&conf->counters[ReadPersistent])) != 0)
|
|
seq_printf(seq, " ReadPersistent=%d(%d)",
|
|
n, conf->period[ReadPersistent]);
|
|
|
|
|
|
if ((n=atomic_read(&conf->counters[ReadFixable])) != 0)
|
|
seq_printf(seq, " ReadFixable=%d(%d)",
|
|
n, conf->period[ReadFixable]);
|
|
|
|
if ((n=atomic_read(&conf->counters[WriteAll])) != 0)
|
|
seq_printf(seq, " WriteAll");
|
|
|
|
seq_printf(seq, " nfaults=%d", conf->nfaults);
|
|
}
|
|
|
|
|
|
static int faulty_reshape(struct mddev *mddev)
|
|
{
|
|
int mode = mddev->new_layout & ModeMask;
|
|
int count = mddev->new_layout >> ModeShift;
|
|
struct faulty_conf *conf = mddev->private;
|
|
|
|
if (mddev->new_layout < 0)
|
|
return 0;
|
|
|
|
/* new layout */
|
|
if (mode == ClearFaults)
|
|
conf->nfaults = 0;
|
|
else if (mode == ClearErrors) {
|
|
int i;
|
|
for (i=0 ; i < Modes ; i++) {
|
|
conf->period[i] = 0;
|
|
atomic_set(&conf->counters[i], 0);
|
|
}
|
|
} else if (mode < Modes) {
|
|
conf->period[mode] = count;
|
|
if (!count) count++;
|
|
atomic_set(&conf->counters[mode], count);
|
|
} else
|
|
return -EINVAL;
|
|
mddev->new_layout = -1;
|
|
mddev->layout = -1; /* makes sure further changes come through */
|
|
return 0;
|
|
}
|
|
|
|
static sector_t faulty_size(struct mddev *mddev, sector_t sectors, int raid_disks)
|
|
{
|
|
WARN_ONCE(raid_disks,
|
|
"%s does not support generic reshape\n", __func__);
|
|
|
|
if (sectors == 0)
|
|
return mddev->dev_sectors;
|
|
|
|
return sectors;
|
|
}
|
|
|
|
static int faulty_run(struct mddev *mddev)
|
|
{
|
|
struct md_rdev *rdev;
|
|
int i;
|
|
struct faulty_conf *conf;
|
|
|
|
if (md_check_no_bitmap(mddev))
|
|
return -EINVAL;
|
|
|
|
conf = kmalloc(sizeof(*conf), GFP_KERNEL);
|
|
if (!conf)
|
|
return -ENOMEM;
|
|
|
|
for (i=0; i<Modes; i++) {
|
|
atomic_set(&conf->counters[i], 0);
|
|
conf->period[i] = 0;
|
|
}
|
|
conf->nfaults = 0;
|
|
|
|
rdev_for_each(rdev, mddev) {
|
|
conf->rdev = rdev;
|
|
disk_stack_limits(mddev->gendisk, rdev->bdev,
|
|
rdev->data_offset << 9);
|
|
}
|
|
|
|
md_set_array_sectors(mddev, faulty_size(mddev, 0, 0));
|
|
mddev->private = conf;
|
|
|
|
faulty_reshape(mddev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void faulty_free(struct mddev *mddev, void *priv)
|
|
{
|
|
struct faulty_conf *conf = priv;
|
|
|
|
kfree(conf);
|
|
}
|
|
|
|
static struct md_personality faulty_personality =
|
|
{
|
|
.name = "faulty",
|
|
.level = LEVEL_FAULTY,
|
|
.owner = THIS_MODULE,
|
|
.make_request = faulty_make_request,
|
|
.run = faulty_run,
|
|
.free = faulty_free,
|
|
.status = faulty_status,
|
|
.check_reshape = faulty_reshape,
|
|
.size = faulty_size,
|
|
};
|
|
|
|
static int __init raid_init(void)
|
|
{
|
|
return register_md_personality(&faulty_personality);
|
|
}
|
|
|
|
static void raid_exit(void)
|
|
{
|
|
unregister_md_personality(&faulty_personality);
|
|
}
|
|
|
|
module_init(raid_init);
|
|
module_exit(raid_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Fault injection personality for MD");
|
|
MODULE_ALIAS("md-personality-10"); /* faulty */
|
|
MODULE_ALIAS("md-faulty");
|
|
MODULE_ALIAS("md-level--5");
|