Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
This commit is contained in:
Linus Torvalds
343
drivers/md/faulty.c
Normal file
343
drivers/md/faulty.c
Normal file
@@ -0,0 +1,343 @@
|
||||
/*
|
||||
* faulty.c : Multiple Devices driver for Linux
|
||||
*
|
||||
* Copyright (C) 2004 Neil Brown
|
||||
*
|
||||
* fautly-device-simulator personality for md
|
||||
*
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2, or (at your option)
|
||||
* any later version.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* (for example /usr/src/linux/COPYING); if not, write to the Free
|
||||
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
|
||||
|
||||
/*
|
||||
* 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 recurrance 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/raid/md.h>
|
||||
|
||||
|
||||
static int faulty_fail(struct bio *bio, unsigned int bytes_done, int error)
|
||||
{
|
||||
struct bio *b = bio->bi_private;
|
||||
|
||||
b->bi_size = bio->bi_size;
|
||||
b->bi_sector = bio->bi_sector;
|
||||
|
||||
if (bio->bi_size == 0)
|
||||
bio_put(bio);
|
||||
|
||||
clear_bit(BIO_UPTODATE, &b->bi_flags);
|
||||
return (b->bi_end_io)(b, bytes_done, -EIO);
|
||||
}
|
||||
|
||||
typedef struct faulty_conf {
|
||||
int period[Modes];
|
||||
atomic_t counters[Modes];
|
||||
sector_t faults[MaxFault];
|
||||
int modes[MaxFault];
|
||||
int nfaults;
|
||||
mdk_rdev_t *rdev;
|
||||
} conf_t;
|
||||
|
||||
static int check_mode(conf_t *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(conf_t *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(conf_t *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 int make_request(request_queue_t *q, struct bio *bio)
|
||||
{
|
||||
mddev_t *mddev = q->queuedata;
|
||||
conf_t *conf = (conf_t*)mddev->private;
|
||||
int failit = 0;
|
||||
|
||||
if (bio->bi_rw & 1) {
|
||||
/* write request */
|
||||
if (atomic_read(&conf->counters[WriteAll])) {
|
||||
/* special case - don't decrement, don't generic_make_request,
|
||||
* just fail immediately
|
||||
*/
|
||||
bio_endio(bio, bio->bi_size, -EIO);
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (check_sector(conf, bio->bi_sector, bio->bi_sector+(bio->bi_size>>9),
|
||||
WRITE))
|
||||
failit = 1;
|
||||
if (check_mode(conf, WritePersistent)) {
|
||||
add_sector(conf, bio->bi_sector, WritePersistent);
|
||||
failit = 1;
|
||||
}
|
||||
if (check_mode(conf, WriteTransient))
|
||||
failit = 1;
|
||||
} else {
|
||||
/* read request */
|
||||
if (check_sector(conf, bio->bi_sector, bio->bi_sector + (bio->bi_size>>9),
|
||||
READ))
|
||||
failit = 1;
|
||||
if (check_mode(conf, ReadTransient))
|
||||
failit = 1;
|
||||
if (check_mode(conf, ReadPersistent)) {
|
||||
add_sector(conf, bio->bi_sector, ReadPersistent);
|
||||
failit = 1;
|
||||
}
|
||||
if (check_mode(conf, ReadFixable)) {
|
||||
add_sector(conf, bio->bi_sector, ReadFixable);
|
||||
failit = 1;
|
||||
}
|
||||
}
|
||||
if (failit) {
|
||||
struct bio *b = bio_clone(bio, GFP_NOIO);
|
||||
b->bi_bdev = conf->rdev->bdev;
|
||||
b->bi_private = bio;
|
||||
b->bi_end_io = faulty_fail;
|
||||
generic_make_request(b);
|
||||
return 0;
|
||||
} else {
|
||||
bio->bi_bdev = conf->rdev->bdev;
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
static void status(struct seq_file *seq, mddev_t *mddev)
|
||||
{
|
||||
conf_t *conf = (conf_t*)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 reconfig(mddev_t *mddev, int layout, int chunk_size)
|
||||
{
|
||||
int mode = layout & ModeMask;
|
||||
int count = layout >> ModeShift;
|
||||
conf_t *conf = mddev->private;
|
||||
|
||||
if (chunk_size != -1)
|
||||
return -EINVAL;
|
||||
|
||||
/* 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->layout = -1; /* makes sure further changes come through */
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int run(mddev_t *mddev)
|
||||
{
|
||||
mdk_rdev_t *rdev;
|
||||
struct list_head *tmp;
|
||||
int i;
|
||||
|
||||
conf_t *conf = kmalloc(sizeof(*conf), GFP_KERNEL);
|
||||
|
||||
for (i=0; i<Modes; i++) {
|
||||
atomic_set(&conf->counters[i], 0);
|
||||
conf->period[i] = 0;
|
||||
}
|
||||
conf->nfaults = 0;
|
||||
|
||||
ITERATE_RDEV(mddev, rdev, tmp)
|
||||
conf->rdev = rdev;
|
||||
|
||||
mddev->array_size = mddev->size;
|
||||
mddev->private = conf;
|
||||
|
||||
reconfig(mddev, mddev->layout, -1);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int stop(mddev_t *mddev)
|
||||
{
|
||||
conf_t *conf = (conf_t *)mddev->private;
|
||||
|
||||
kfree(conf);
|
||||
mddev->private = NULL;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static mdk_personality_t faulty_personality =
|
||||
{
|
||||
.name = "faulty",
|
||||
.owner = THIS_MODULE,
|
||||
.make_request = make_request,
|
||||
.run = run,
|
||||
.stop = stop,
|
||||
.status = status,
|
||||
.reconfig = reconfig,
|
||||
};
|
||||
|
||||
static int __init raid_init(void)
|
||||
{
|
||||
return register_md_personality(FAULTY, &faulty_personality);
|
||||
}
|
||||
|
||||
static void raid_exit(void)
|
||||
{
|
||||
unregister_md_personality(FAULTY);
|
||||
}
|
||||
|
||||
module_init(raid_init);
|
||||
module_exit(raid_exit);
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_ALIAS("md-personality-10"); /* faulty */
|
||||
Reference in New Issue
Block a user