blob: 2dc22dddb2ae31abe4b5bb2371dfb8eaedfeec73 [file] [log] [blame]
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -07001/*
2 * Copyright (C) 2005-2007 Red Hat GmbH
3 *
4 * A target that delays reads and/or writes and can send
5 * them to different devices.
6 *
7 * This file is released under the GPL.
8 */
9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/blkdev.h>
13#include <linux/bio.h>
14#include <linux/slab.h>
15
Mikulas Patocka586e80e2008-10-21 17:44:59 +010016#include <linux/device-mapper.h>
17
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -070018#define DM_MSG_PREFIX "delay"
19
20struct delay_c {
21 struct timer_list delay_timer;
Alasdair G Kergonac818642007-07-12 17:26:47 +010022 struct mutex timer_lock;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -070023 struct work_struct flush_expired_bios;
24 struct list_head delayed_bios;
25 atomic_t may_delay;
26 mempool_t *delayed_pool;
27
28 struct dm_dev *dev_read;
29 sector_t start_read;
30 unsigned read_delay;
31 unsigned reads;
32
33 struct dm_dev *dev_write;
34 sector_t start_write;
35 unsigned write_delay;
36 unsigned writes;
37};
38
Alasdair G Kergon028867a2007-07-12 17:26:32 +010039struct dm_delay_info {
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -070040 struct delay_c *context;
41 struct list_head list;
42 struct bio *bio;
43 unsigned long expires;
44};
45
46static DEFINE_MUTEX(delayed_bios_lock);
47
48static struct workqueue_struct *kdelayd_wq;
49static struct kmem_cache *delayed_cache;
50
51static void handle_delayed_timer(unsigned long data)
52{
53 struct delay_c *dc = (struct delay_c *)data;
54
55 queue_work(kdelayd_wq, &dc->flush_expired_bios);
56}
57
58static void queue_timeout(struct delay_c *dc, unsigned long expires)
59{
Alasdair G Kergonac818642007-07-12 17:26:47 +010060 mutex_lock(&dc->timer_lock);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -070061
62 if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
63 mod_timer(&dc->delay_timer, expires);
64
Alasdair G Kergonac818642007-07-12 17:26:47 +010065 mutex_unlock(&dc->timer_lock);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -070066}
67
68static void flush_bios(struct bio *bio)
69{
70 struct bio *n;
71
72 while (bio) {
73 n = bio->bi_next;
74 bio->bi_next = NULL;
75 generic_make_request(bio);
76 bio = n;
77 }
78}
79
80static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
81{
Alasdair G Kergon028867a2007-07-12 17:26:32 +010082 struct dm_delay_info *delayed, *next;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -070083 unsigned long next_expires = 0;
84 int start_timer = 0;
Alasdair G Kergon051814c2007-10-19 22:38:55 +010085 struct bio_list flush_bios = { };
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -070086
87 mutex_lock(&delayed_bios_lock);
88 list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
89 if (flush_all || time_after_eq(jiffies, delayed->expires)) {
90 list_del(&delayed->list);
91 bio_list_add(&flush_bios, delayed->bio);
92 if ((bio_data_dir(delayed->bio) == WRITE))
93 delayed->context->writes--;
94 else
95 delayed->context->reads--;
96 mempool_free(delayed, dc->delayed_pool);
97 continue;
98 }
99
100 if (!start_timer) {
101 start_timer = 1;
102 next_expires = delayed->expires;
103 } else
104 next_expires = min(next_expires, delayed->expires);
105 }
106
107 mutex_unlock(&delayed_bios_lock);
108
109 if (start_timer)
110 queue_timeout(dc, next_expires);
111
112 return bio_list_get(&flush_bios);
113}
114
115static void flush_expired_bios(struct work_struct *work)
116{
117 struct delay_c *dc;
118
119 dc = container_of(work, struct delay_c, flush_expired_bios);
120 flush_bios(flush_delayed_bios(dc, 0));
121}
122
123/*
124 * Mapping parameters:
125 * <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
126 *
127 * With separate write parameters, the first set is only used for reads.
128 * Delays are specified in milliseconds.
129 */
130static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
131{
132 struct delay_c *dc;
133 unsigned long long tmpll;
Mikulas Patocka31998ef2012-03-28 18:41:26 +0100134 char dummy;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700135
136 if (argc != 3 && argc != 6) {
137 ti->error = "requires exactly 3 or 6 arguments";
138 return -EINVAL;
139 }
140
141 dc = kmalloc(sizeof(*dc), GFP_KERNEL);
142 if (!dc) {
143 ti->error = "Cannot allocate context";
144 return -ENOMEM;
145 }
146
147 dc->reads = dc->writes = 0;
148
Mikulas Patocka31998ef2012-03-28 18:41:26 +0100149 if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700150 ti->error = "Invalid device sector";
151 goto bad;
152 }
153 dc->start_read = tmpll;
154
Mikulas Patocka31998ef2012-03-28 18:41:26 +0100155 if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) {
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700156 ti->error = "Invalid delay";
157 goto bad;
158 }
159
Nikanth Karthikesan8215d6e2010-03-06 02:32:27 +0000160 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
161 &dc->dev_read)) {
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700162 ti->error = "Device lookup failed";
163 goto bad;
164 }
165
Dmitry Monakhov2e64a0f2007-10-19 22:38:41 +0100166 dc->dev_write = NULL;
167 if (argc == 3)
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700168 goto out;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700169
Mikulas Patocka31998ef2012-03-28 18:41:26 +0100170 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700171 ti->error = "Invalid write device sector";
Dmitry Monakhov2e64a0f2007-10-19 22:38:41 +0100172 goto bad_dev_read;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700173 }
174 dc->start_write = tmpll;
175
Mikulas Patocka31998ef2012-03-28 18:41:26 +0100176 if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) {
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700177 ti->error = "Invalid write delay";
Dmitry Monakhov2e64a0f2007-10-19 22:38:41 +0100178 goto bad_dev_read;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700179 }
180
Nikanth Karthikesan8215d6e2010-03-06 02:32:27 +0000181 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
182 &dc->dev_write)) {
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700183 ti->error = "Write device lookup failed";
Dmitry Monakhov2e64a0f2007-10-19 22:38:41 +0100184 goto bad_dev_read;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700185 }
186
187out:
188 dc->delayed_pool = mempool_create_slab_pool(128, delayed_cache);
189 if (!dc->delayed_pool) {
190 DMERR("Couldn't create delayed bio pool.");
Dmitry Monakhov2e64a0f2007-10-19 22:38:41 +0100191 goto bad_dev_write;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700192 }
193
Alasdair G Kergonac818642007-07-12 17:26:47 +0100194 setup_timer(&dc->delay_timer, handle_delayed_timer, (unsigned long)dc);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700195
196 INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
197 INIT_LIST_HEAD(&dc->delayed_bios);
Alasdair G Kergonac818642007-07-12 17:26:47 +0100198 mutex_init(&dc->timer_lock);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700199 atomic_set(&dc->may_delay, 1);
200
Mikulas Patockac9272592009-06-22 10:12:23 +0100201 ti->num_flush_requests = 1;
Mike Snitzer3fd5d482010-08-12 04:14:13 +0100202 ti->num_discard_requests = 1;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700203 ti->private = dc;
204 return 0;
205
Dmitry Monakhov2e64a0f2007-10-19 22:38:41 +0100206bad_dev_write:
207 if (dc->dev_write)
208 dm_put_device(ti, dc->dev_write);
209bad_dev_read:
210 dm_put_device(ti, dc->dev_read);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700211bad:
212 kfree(dc);
213 return -EINVAL;
214}
215
216static void delay_dtr(struct dm_target *ti)
217{
218 struct delay_c *dc = ti->private;
219
220 flush_workqueue(kdelayd_wq);
221
222 dm_put_device(ti, dc->dev_read);
223
224 if (dc->dev_write)
225 dm_put_device(ti, dc->dev_write);
226
227 mempool_destroy(dc->delayed_pool);
228 kfree(dc);
229}
230
231static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
232{
Alasdair G Kergon028867a2007-07-12 17:26:32 +0100233 struct dm_delay_info *delayed;
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700234 unsigned long expires = 0;
235
236 if (!delay || !atomic_read(&dc->may_delay))
237 return 1;
238
239 delayed = mempool_alloc(dc->delayed_pool, GFP_NOIO);
240
241 delayed->context = dc;
242 delayed->bio = bio;
243 delayed->expires = expires = jiffies + (delay * HZ / 1000);
244
245 mutex_lock(&delayed_bios_lock);
246
247 if (bio_data_dir(bio) == WRITE)
248 dc->writes++;
249 else
250 dc->reads++;
251
252 list_add_tail(&delayed->list, &dc->delayed_bios);
253
254 mutex_unlock(&delayed_bios_lock);
255
256 queue_timeout(dc, expires);
257
258 return 0;
259}
260
261static void delay_presuspend(struct dm_target *ti)
262{
263 struct delay_c *dc = ti->private;
264
265 atomic_set(&dc->may_delay, 0);
266 del_timer_sync(&dc->delay_timer);
267 flush_bios(flush_delayed_bios(dc, 1));
268}
269
270static void delay_resume(struct dm_target *ti)
271{
272 struct delay_c *dc = ti->private;
273
274 atomic_set(&dc->may_delay, 1);
275}
276
277static int delay_map(struct dm_target *ti, struct bio *bio,
278 union map_info *map_context)
279{
280 struct delay_c *dc = ti->private;
281
282 if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) {
283 bio->bi_bdev = dc->dev_write->bdev;
Mikulas Patockac9272592009-06-22 10:12:23 +0100284 if (bio_sectors(bio))
285 bio->bi_sector = dc->start_write +
Alasdair G Kergonb441a2622010-08-12 04:14:11 +0100286 dm_target_offset(ti, bio->bi_sector);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700287
288 return delay_bio(dc, dc->write_delay, bio);
289 }
290
291 bio->bi_bdev = dc->dev_read->bdev;
Alasdair G Kergonb441a2622010-08-12 04:14:11 +0100292 bio->bi_sector = dc->start_read + dm_target_offset(ti, bio->bi_sector);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700293
294 return delay_bio(dc, dc->read_delay, bio);
295}
296
297static int delay_status(struct dm_target *ti, status_type_t type,
298 char *result, unsigned maxlen)
299{
300 struct delay_c *dc = ti->private;
301 int sz = 0;
302
303 switch (type) {
304 case STATUSTYPE_INFO:
305 DMEMIT("%u %u", dc->reads, dc->writes);
306 break;
307
308 case STATUSTYPE_TABLE:
309 DMEMIT("%s %llu %u", dc->dev_read->name,
310 (unsigned long long) dc->start_read,
311 dc->read_delay);
312 if (dc->dev_write)
Milan Broz79662d12007-10-19 22:38:42 +0100313 DMEMIT(" %s %llu %u", dc->dev_write->name,
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700314 (unsigned long long) dc->start_write,
315 dc->write_delay);
316 break;
317 }
318
319 return 0;
320}
321
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100322static int delay_iterate_devices(struct dm_target *ti,
323 iterate_devices_callout_fn fn, void *data)
324{
325 struct delay_c *dc = ti->private;
326 int ret = 0;
327
Mike Snitzer5dea2712009-07-23 20:30:42 +0100328 ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data);
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100329 if (ret)
330 goto out;
331
332 if (dc->dev_write)
Mike Snitzer5dea2712009-07-23 20:30:42 +0100333 ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data);
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100334
335out:
336 return ret;
337}
338
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700339static struct target_type delay_target = {
340 .name = "delay",
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100341 .version = {1, 1, 0},
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700342 .module = THIS_MODULE,
343 .ctr = delay_ctr,
344 .dtr = delay_dtr,
345 .map = delay_map,
346 .presuspend = delay_presuspend,
347 .resume = delay_resume,
348 .status = delay_status,
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100349 .iterate_devices = delay_iterate_devices,
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700350};
351
352static int __init dm_delay_init(void)
353{
354 int r = -ENOMEM;
355
Tejun Heo4d4d66a2011-01-13 19:59:57 +0000356 kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700357 if (!kdelayd_wq) {
358 DMERR("Couldn't start kdelayd");
359 goto bad_queue;
360 }
361
Alasdair G Kergon028867a2007-07-12 17:26:32 +0100362 delayed_cache = KMEM_CACHE(dm_delay_info, 0);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700363 if (!delayed_cache) {
364 DMERR("Couldn't create delayed bio cache.");
365 goto bad_memcache;
366 }
367
368 r = dm_register_target(&delay_target);
369 if (r < 0) {
370 DMERR("register failed %d", r);
371 goto bad_register;
372 }
373
374 return 0;
375
376bad_register:
377 kmem_cache_destroy(delayed_cache);
378bad_memcache:
379 destroy_workqueue(kdelayd_wq);
380bad_queue:
381 return r;
382}
383
384static void __exit dm_delay_exit(void)
385{
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000386 dm_unregister_target(&delay_target);
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700387 kmem_cache_destroy(delayed_cache);
388 destroy_workqueue(kdelayd_wq);
389}
390
391/* Module hooks */
392module_init(dm_delay_init);
393module_exit(dm_delay_exit);
394
395MODULE_DESCRIPTION(DM_NAME " delay target");
396MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");
397MODULE_LICENSE("GPL");