381 lines
8.1 KiB
C
381 lines
8.1 KiB
C
/*
|
|
* Copyright (C) 2005-2007 Red Hat GmbH
|
|
*
|
|
* A target that delays reads and/or writes and can send
|
|
* them to different devices.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/slab.h>
|
|
|
|
#include <linux/device-mapper.h>
|
|
|
|
#define DM_MSG_PREFIX "delay"
|
|
|
|
struct delay_c {
|
|
struct timer_list delay_timer;
|
|
struct mutex timer_lock;
|
|
struct workqueue_struct *kdelayd_wq;
|
|
struct work_struct flush_expired_bios;
|
|
struct list_head delayed_bios;
|
|
atomic_t may_delay;
|
|
|
|
struct dm_dev *dev_read;
|
|
sector_t start_read;
|
|
unsigned read_delay;
|
|
unsigned reads;
|
|
|
|
struct dm_dev *dev_write;
|
|
sector_t start_write;
|
|
unsigned write_delay;
|
|
unsigned writes;
|
|
};
|
|
|
|
struct dm_delay_info {
|
|
struct delay_c *context;
|
|
struct list_head list;
|
|
unsigned long expires;
|
|
};
|
|
|
|
static DEFINE_MUTEX(delayed_bios_lock);
|
|
|
|
static void handle_delayed_timer(unsigned long data)
|
|
{
|
|
struct delay_c *dc = (struct delay_c *)data;
|
|
|
|
queue_work(dc->kdelayd_wq, &dc->flush_expired_bios);
|
|
}
|
|
|
|
static void queue_timeout(struct delay_c *dc, unsigned long expires)
|
|
{
|
|
mutex_lock(&dc->timer_lock);
|
|
|
|
if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
|
|
mod_timer(&dc->delay_timer, expires);
|
|
|
|
mutex_unlock(&dc->timer_lock);
|
|
}
|
|
|
|
static void flush_bios(struct bio *bio)
|
|
{
|
|
struct bio *n;
|
|
|
|
while (bio) {
|
|
n = bio->bi_next;
|
|
bio->bi_next = NULL;
|
|
generic_make_request(bio);
|
|
bio = n;
|
|
}
|
|
}
|
|
|
|
static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
|
|
{
|
|
struct dm_delay_info *delayed, *next;
|
|
unsigned long next_expires = 0;
|
|
int start_timer = 0;
|
|
struct bio_list flush_bios = { };
|
|
|
|
mutex_lock(&delayed_bios_lock);
|
|
list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
|
|
if (flush_all || time_after_eq(jiffies, delayed->expires)) {
|
|
struct bio *bio = dm_bio_from_per_bio_data(delayed,
|
|
sizeof(struct dm_delay_info));
|
|
list_del(&delayed->list);
|
|
bio_list_add(&flush_bios, bio);
|
|
if ((bio_data_dir(bio) == WRITE))
|
|
delayed->context->writes--;
|
|
else
|
|
delayed->context->reads--;
|
|
continue;
|
|
}
|
|
|
|
if (!start_timer) {
|
|
start_timer = 1;
|
|
next_expires = delayed->expires;
|
|
} else
|
|
next_expires = min(next_expires, delayed->expires);
|
|
}
|
|
|
|
mutex_unlock(&delayed_bios_lock);
|
|
|
|
if (start_timer)
|
|
queue_timeout(dc, next_expires);
|
|
|
|
return bio_list_get(&flush_bios);
|
|
}
|
|
|
|
static void flush_expired_bios(struct work_struct *work)
|
|
{
|
|
struct delay_c *dc;
|
|
|
|
dc = container_of(work, struct delay_c, flush_expired_bios);
|
|
flush_bios(flush_delayed_bios(dc, 0));
|
|
}
|
|
|
|
/*
|
|
* Mapping parameters:
|
|
* <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
|
|
*
|
|
* With separate write parameters, the first set is only used for reads.
|
|
* Offsets are specified in sectors.
|
|
* Delays are specified in milliseconds.
|
|
*/
|
|
static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
|
|
{
|
|
struct delay_c *dc;
|
|
unsigned long long tmpll;
|
|
char dummy;
|
|
int ret;
|
|
|
|
if (argc != 3 && argc != 6) {
|
|
ti->error = "Requires exactly 3 or 6 arguments";
|
|
return -EINVAL;
|
|
}
|
|
|
|
dc = kmalloc(sizeof(*dc), GFP_KERNEL);
|
|
if (!dc) {
|
|
ti->error = "Cannot allocate context";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
dc->reads = dc->writes = 0;
|
|
|
|
ret = -EINVAL;
|
|
if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
|
|
ti->error = "Invalid device sector";
|
|
goto bad;
|
|
}
|
|
dc->start_read = tmpll;
|
|
|
|
if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) {
|
|
ti->error = "Invalid delay";
|
|
goto bad;
|
|
}
|
|
|
|
ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
|
|
&dc->dev_read);
|
|
if (ret) {
|
|
ti->error = "Device lookup failed";
|
|
goto bad;
|
|
}
|
|
|
|
ret = -EINVAL;
|
|
dc->dev_write = NULL;
|
|
if (argc == 3)
|
|
goto out;
|
|
|
|
if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
|
|
ti->error = "Invalid write device sector";
|
|
goto bad_dev_read;
|
|
}
|
|
dc->start_write = tmpll;
|
|
|
|
if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) {
|
|
ti->error = "Invalid write delay";
|
|
goto bad_dev_read;
|
|
}
|
|
|
|
ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
|
|
&dc->dev_write);
|
|
if (ret) {
|
|
ti->error = "Write device lookup failed";
|
|
goto bad_dev_read;
|
|
}
|
|
|
|
out:
|
|
ret = -EINVAL;
|
|
dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
|
|
if (!dc->kdelayd_wq) {
|
|
DMERR("Couldn't start kdelayd");
|
|
goto bad_queue;
|
|
}
|
|
|
|
setup_timer(&dc->delay_timer, handle_delayed_timer, (unsigned long)dc);
|
|
|
|
INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
|
|
INIT_LIST_HEAD(&dc->delayed_bios);
|
|
mutex_init(&dc->timer_lock);
|
|
atomic_set(&dc->may_delay, 1);
|
|
|
|
ti->num_flush_bios = 1;
|
|
ti->num_discard_bios = 1;
|
|
ti->per_io_data_size = sizeof(struct dm_delay_info);
|
|
ti->private = dc;
|
|
return 0;
|
|
|
|
bad_queue:
|
|
if (dc->dev_write)
|
|
dm_put_device(ti, dc->dev_write);
|
|
bad_dev_read:
|
|
dm_put_device(ti, dc->dev_read);
|
|
bad:
|
|
kfree(dc);
|
|
return ret;
|
|
}
|
|
|
|
static void delay_dtr(struct dm_target *ti)
|
|
{
|
|
struct delay_c *dc = ti->private;
|
|
|
|
destroy_workqueue(dc->kdelayd_wq);
|
|
|
|
dm_put_device(ti, dc->dev_read);
|
|
|
|
if (dc->dev_write)
|
|
dm_put_device(ti, dc->dev_write);
|
|
|
|
kfree(dc);
|
|
}
|
|
|
|
static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
|
|
{
|
|
struct dm_delay_info *delayed;
|
|
unsigned long expires = 0;
|
|
|
|
if (!delay || !atomic_read(&dc->may_delay))
|
|
return DM_MAPIO_REMAPPED;
|
|
|
|
delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
|
|
|
|
delayed->context = dc;
|
|
delayed->expires = expires = jiffies + msecs_to_jiffies(delay);
|
|
|
|
mutex_lock(&delayed_bios_lock);
|
|
|
|
if (bio_data_dir(bio) == WRITE)
|
|
dc->writes++;
|
|
else
|
|
dc->reads++;
|
|
|
|
list_add_tail(&delayed->list, &dc->delayed_bios);
|
|
|
|
mutex_unlock(&delayed_bios_lock);
|
|
|
|
queue_timeout(dc, expires);
|
|
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
static void delay_presuspend(struct dm_target *ti)
|
|
{
|
|
struct delay_c *dc = ti->private;
|
|
|
|
atomic_set(&dc->may_delay, 0);
|
|
del_timer_sync(&dc->delay_timer);
|
|
flush_bios(flush_delayed_bios(dc, 1));
|
|
}
|
|
|
|
static void delay_resume(struct dm_target *ti)
|
|
{
|
|
struct delay_c *dc = ti->private;
|
|
|
|
atomic_set(&dc->may_delay, 1);
|
|
}
|
|
|
|
static int delay_map(struct dm_target *ti, struct bio *bio)
|
|
{
|
|
struct delay_c *dc = ti->private;
|
|
|
|
if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) {
|
|
bio->bi_bdev = dc->dev_write->bdev;
|
|
if (bio_sectors(bio))
|
|
bio->bi_iter.bi_sector = dc->start_write +
|
|
dm_target_offset(ti, bio->bi_iter.bi_sector);
|
|
|
|
return delay_bio(dc, dc->write_delay, bio);
|
|
}
|
|
|
|
bio->bi_bdev = dc->dev_read->bdev;
|
|
bio->bi_iter.bi_sector = dc->start_read +
|
|
dm_target_offset(ti, bio->bi_iter.bi_sector);
|
|
|
|
return delay_bio(dc, dc->read_delay, bio);
|
|
}
|
|
|
|
static void delay_status(struct dm_target *ti, status_type_t type,
|
|
unsigned status_flags, char *result, unsigned maxlen)
|
|
{
|
|
struct delay_c *dc = ti->private;
|
|
int sz = 0;
|
|
|
|
switch (type) {
|
|
case STATUSTYPE_INFO:
|
|
DMEMIT("%u %u", dc->reads, dc->writes);
|
|
break;
|
|
|
|
case STATUSTYPE_TABLE:
|
|
DMEMIT("%s %llu %u", dc->dev_read->name,
|
|
(unsigned long long) dc->start_read,
|
|
dc->read_delay);
|
|
if (dc->dev_write)
|
|
DMEMIT(" %s %llu %u", dc->dev_write->name,
|
|
(unsigned long long) dc->start_write,
|
|
dc->write_delay);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static int delay_iterate_devices(struct dm_target *ti,
|
|
iterate_devices_callout_fn fn, void *data)
|
|
{
|
|
struct delay_c *dc = ti->private;
|
|
int ret = 0;
|
|
|
|
ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (dc->dev_write)
|
|
ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data);
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static struct target_type delay_target = {
|
|
.name = "delay",
|
|
.version = {1, 2, 1},
|
|
.module = THIS_MODULE,
|
|
.ctr = delay_ctr,
|
|
.dtr = delay_dtr,
|
|
.map = delay_map,
|
|
.presuspend = delay_presuspend,
|
|
.resume = delay_resume,
|
|
.status = delay_status,
|
|
.iterate_devices = delay_iterate_devices,
|
|
};
|
|
|
|
static int __init dm_delay_init(void)
|
|
{
|
|
int r;
|
|
|
|
r = dm_register_target(&delay_target);
|
|
if (r < 0) {
|
|
DMERR("register failed %d", r);
|
|
goto bad_register;
|
|
}
|
|
|
|
return 0;
|
|
|
|
bad_register:
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_delay_exit(void)
|
|
{
|
|
dm_unregister_target(&delay_target);
|
|
}
|
|
|
|
/* Module hooks */
|
|
module_init(dm_delay_init);
|
|
module_exit(dm_delay_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " delay target");
|
|
MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|