Commit | Line | Data |
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26b9f228 HM |
1 | /* |
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 | ||
586e80e6 MP |
16 | #include <linux/device-mapper.h> |
17 | ||
26b9f228 HM |
18 | #define DM_MSG_PREFIX "delay" |
19 | ||
20 | struct delay_c { | |
21 | struct timer_list delay_timer; | |
ac818646 | 22 | struct mutex timer_lock; |
718822c1 | 23 | struct workqueue_struct *kdelayd_wq; |
26b9f228 HM |
24 | struct work_struct flush_expired_bios; |
25 | struct list_head delayed_bios; | |
26 | atomic_t may_delay; | |
26b9f228 HM |
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 | ||
028867ac | 39 | struct dm_delay_info { |
26b9f228 HM |
40 | struct delay_c *context; |
41 | struct list_head list; | |
26b9f228 HM |
42 | unsigned long expires; |
43 | }; | |
44 | ||
45 | static DEFINE_MUTEX(delayed_bios_lock); | |
46 | ||
26b9f228 HM |
47 | static void handle_delayed_timer(unsigned long data) |
48 | { | |
49 | struct delay_c *dc = (struct delay_c *)data; | |
50 | ||
718822c1 | 51 | queue_work(dc->kdelayd_wq, &dc->flush_expired_bios); |
26b9f228 HM |
52 | } |
53 | ||
54 | static void queue_timeout(struct delay_c *dc, unsigned long expires) | |
55 | { | |
ac818646 | 56 | mutex_lock(&dc->timer_lock); |
26b9f228 HM |
57 | |
58 | if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires) | |
59 | mod_timer(&dc->delay_timer, expires); | |
60 | ||
ac818646 | 61 | mutex_unlock(&dc->timer_lock); |
26b9f228 HM |
62 | } |
63 | ||
64 | static void flush_bios(struct bio *bio) | |
65 | { | |
66 | struct bio *n; | |
67 | ||
68 | while (bio) { | |
69 | n = bio->bi_next; | |
70 | bio->bi_next = NULL; | |
71 | generic_make_request(bio); | |
72 | bio = n; | |
73 | } | |
74 | } | |
75 | ||
76 | static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all) | |
77 | { | |
028867ac | 78 | struct dm_delay_info *delayed, *next; |
26b9f228 HM |
79 | unsigned long next_expires = 0; |
80 | int start_timer = 0; | |
051814c6 | 81 | struct bio_list flush_bios = { }; |
26b9f228 HM |
82 | |
83 | mutex_lock(&delayed_bios_lock); | |
84 | list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) { | |
85 | if (flush_all || time_after_eq(jiffies, delayed->expires)) { | |
42065460 MP |
86 | struct bio *bio = dm_bio_from_per_bio_data(delayed, |
87 | sizeof(struct dm_delay_info)); | |
26b9f228 | 88 | list_del(&delayed->list); |
42065460 MP |
89 | bio_list_add(&flush_bios, bio); |
90 | if ((bio_data_dir(bio) == WRITE)) | |
26b9f228 HM |
91 | delayed->context->writes--; |
92 | else | |
93 | delayed->context->reads--; | |
26b9f228 HM |
94 | continue; |
95 | } | |
96 | ||
97 | if (!start_timer) { | |
98 | start_timer = 1; | |
99 | next_expires = delayed->expires; | |
100 | } else | |
101 | next_expires = min(next_expires, delayed->expires); | |
102 | } | |
103 | ||
104 | mutex_unlock(&delayed_bios_lock); | |
105 | ||
106 | if (start_timer) | |
107 | queue_timeout(dc, next_expires); | |
108 | ||
109 | return bio_list_get(&flush_bios); | |
110 | } | |
111 | ||
112 | static void flush_expired_bios(struct work_struct *work) | |
113 | { | |
114 | struct delay_c *dc; | |
115 | ||
116 | dc = container_of(work, struct delay_c, flush_expired_bios); | |
117 | flush_bios(flush_delayed_bios(dc, 0)); | |
118 | } | |
119 | ||
120 | /* | |
121 | * Mapping parameters: | |
122 | * <device> <offset> <delay> [<write_device> <write_offset> <write_delay>] | |
123 | * | |
124 | * With separate write parameters, the first set is only used for reads. | |
125 | * Delays are specified in milliseconds. | |
126 | */ | |
127 | static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
128 | { | |
129 | struct delay_c *dc; | |
130 | unsigned long long tmpll; | |
31998ef1 | 131 | char dummy; |
26b9f228 HM |
132 | |
133 | if (argc != 3 && argc != 6) { | |
134 | ti->error = "requires exactly 3 or 6 arguments"; | |
135 | return -EINVAL; | |
136 | } | |
137 | ||
138 | dc = kmalloc(sizeof(*dc), GFP_KERNEL); | |
139 | if (!dc) { | |
140 | ti->error = "Cannot allocate context"; | |
141 | return -ENOMEM; | |
142 | } | |
143 | ||
144 | dc->reads = dc->writes = 0; | |
145 | ||
31998ef1 | 146 | if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) { |
26b9f228 HM |
147 | ti->error = "Invalid device sector"; |
148 | goto bad; | |
149 | } | |
150 | dc->start_read = tmpll; | |
151 | ||
31998ef1 | 152 | if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) { |
26b9f228 HM |
153 | ti->error = "Invalid delay"; |
154 | goto bad; | |
155 | } | |
156 | ||
8215d6ec NK |
157 | if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), |
158 | &dc->dev_read)) { | |
26b9f228 HM |
159 | ti->error = "Device lookup failed"; |
160 | goto bad; | |
161 | } | |
162 | ||
2e64a0f9 DM |
163 | dc->dev_write = NULL; |
164 | if (argc == 3) | |
26b9f228 | 165 | goto out; |
26b9f228 | 166 | |
31998ef1 | 167 | if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) { |
26b9f228 | 168 | ti->error = "Invalid write device sector"; |
2e64a0f9 | 169 | goto bad_dev_read; |
26b9f228 HM |
170 | } |
171 | dc->start_write = tmpll; | |
172 | ||
31998ef1 | 173 | if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) { |
26b9f228 | 174 | ti->error = "Invalid write delay"; |
2e64a0f9 | 175 | goto bad_dev_read; |
26b9f228 HM |
176 | } |
177 | ||
8215d6ec NK |
178 | if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), |
179 | &dc->dev_write)) { | |
26b9f228 | 180 | ti->error = "Write device lookup failed"; |
2e64a0f9 | 181 | goto bad_dev_read; |
26b9f228 HM |
182 | } |
183 | ||
184 | out: | |
718822c1 MP |
185 | dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0); |
186 | if (!dc->kdelayd_wq) { | |
187 | DMERR("Couldn't start kdelayd"); | |
188 | goto bad_queue; | |
189 | } | |
190 | ||
ac818646 | 191 | setup_timer(&dc->delay_timer, handle_delayed_timer, (unsigned long)dc); |
26b9f228 HM |
192 | |
193 | INIT_WORK(&dc->flush_expired_bios, flush_expired_bios); | |
194 | INIT_LIST_HEAD(&dc->delayed_bios); | |
ac818646 | 195 | mutex_init(&dc->timer_lock); |
26b9f228 HM |
196 | atomic_set(&dc->may_delay, 1); |
197 | ||
55a62eef AK |
198 | ti->num_flush_bios = 1; |
199 | ti->num_discard_bios = 1; | |
42065460 | 200 | ti->per_bio_data_size = sizeof(struct dm_delay_info); |
26b9f228 HM |
201 | ti->private = dc; |
202 | return 0; | |
203 | ||
718822c1 | 204 | bad_queue: |
2e64a0f9 DM |
205 | if (dc->dev_write) |
206 | dm_put_device(ti, dc->dev_write); | |
207 | bad_dev_read: | |
208 | dm_put_device(ti, dc->dev_read); | |
26b9f228 HM |
209 | bad: |
210 | kfree(dc); | |
211 | return -EINVAL; | |
212 | } | |
213 | ||
214 | static void delay_dtr(struct dm_target *ti) | |
215 | { | |
216 | struct delay_c *dc = ti->private; | |
217 | ||
718822c1 | 218 | destroy_workqueue(dc->kdelayd_wq); |
26b9f228 HM |
219 | |
220 | dm_put_device(ti, dc->dev_read); | |
221 | ||
222 | if (dc->dev_write) | |
223 | dm_put_device(ti, dc->dev_write); | |
224 | ||
26b9f228 HM |
225 | kfree(dc); |
226 | } | |
227 | ||
228 | static int delay_bio(struct delay_c *dc, int delay, struct bio *bio) | |
229 | { | |
028867ac | 230 | struct dm_delay_info *delayed; |
26b9f228 HM |
231 | unsigned long expires = 0; |
232 | ||
233 | if (!delay || !atomic_read(&dc->may_delay)) | |
234 | return 1; | |
235 | ||
42065460 | 236 | delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info)); |
26b9f228 HM |
237 | |
238 | delayed->context = dc; | |
26b9f228 HM |
239 | delayed->expires = expires = jiffies + (delay * HZ / 1000); |
240 | ||
241 | mutex_lock(&delayed_bios_lock); | |
242 | ||
243 | if (bio_data_dir(bio) == WRITE) | |
244 | dc->writes++; | |
245 | else | |
246 | dc->reads++; | |
247 | ||
248 | list_add_tail(&delayed->list, &dc->delayed_bios); | |
249 | ||
250 | mutex_unlock(&delayed_bios_lock); | |
251 | ||
252 | queue_timeout(dc, expires); | |
253 | ||
254 | return 0; | |
255 | } | |
256 | ||
257 | static void delay_presuspend(struct dm_target *ti) | |
258 | { | |
259 | struct delay_c *dc = ti->private; | |
260 | ||
261 | atomic_set(&dc->may_delay, 0); | |
262 | del_timer_sync(&dc->delay_timer); | |
263 | flush_bios(flush_delayed_bios(dc, 1)); | |
264 | } | |
265 | ||
266 | static void delay_resume(struct dm_target *ti) | |
267 | { | |
268 | struct delay_c *dc = ti->private; | |
269 | ||
270 | atomic_set(&dc->may_delay, 1); | |
271 | } | |
272 | ||
7de3ee57 | 273 | static int delay_map(struct dm_target *ti, struct bio *bio) |
26b9f228 HM |
274 | { |
275 | struct delay_c *dc = ti->private; | |
276 | ||
277 | if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) { | |
278 | bio->bi_bdev = dc->dev_write->bdev; | |
c927259e | 279 | if (bio_sectors(bio)) |
4f024f37 KO |
280 | bio->bi_iter.bi_sector = dc->start_write + |
281 | dm_target_offset(ti, bio->bi_iter.bi_sector); | |
26b9f228 HM |
282 | |
283 | return delay_bio(dc, dc->write_delay, bio); | |
284 | } | |
285 | ||
286 | bio->bi_bdev = dc->dev_read->bdev; | |
4f024f37 KO |
287 | bio->bi_iter.bi_sector = dc->start_read + |
288 | dm_target_offset(ti, bio->bi_iter.bi_sector); | |
26b9f228 HM |
289 | |
290 | return delay_bio(dc, dc->read_delay, bio); | |
291 | } | |
292 | ||
fd7c092e MP |
293 | static void delay_status(struct dm_target *ti, status_type_t type, |
294 | unsigned status_flags, char *result, unsigned maxlen) | |
26b9f228 HM |
295 | { |
296 | struct delay_c *dc = ti->private; | |
297 | int sz = 0; | |
298 | ||
299 | switch (type) { | |
300 | case STATUSTYPE_INFO: | |
301 | DMEMIT("%u %u", dc->reads, dc->writes); | |
302 | break; | |
303 | ||
304 | case STATUSTYPE_TABLE: | |
305 | DMEMIT("%s %llu %u", dc->dev_read->name, | |
306 | (unsigned long long) dc->start_read, | |
307 | dc->read_delay); | |
308 | if (dc->dev_write) | |
79662d1e | 309 | DMEMIT(" %s %llu %u", dc->dev_write->name, |
26b9f228 HM |
310 | (unsigned long long) dc->start_write, |
311 | dc->write_delay); | |
312 | break; | |
313 | } | |
26b9f228 HM |
314 | } |
315 | ||
af4874e0 MS |
316 | static int delay_iterate_devices(struct dm_target *ti, |
317 | iterate_devices_callout_fn fn, void *data) | |
318 | { | |
319 | struct delay_c *dc = ti->private; | |
320 | int ret = 0; | |
321 | ||
5dea271b | 322 | ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data); |
af4874e0 MS |
323 | if (ret) |
324 | goto out; | |
325 | ||
326 | if (dc->dev_write) | |
5dea271b | 327 | ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data); |
af4874e0 MS |
328 | |
329 | out: | |
330 | return ret; | |
331 | } | |
332 | ||
26b9f228 HM |
333 | static struct target_type delay_target = { |
334 | .name = "delay", | |
fd7c092e | 335 | .version = {1, 2, 1}, |
26b9f228 HM |
336 | .module = THIS_MODULE, |
337 | .ctr = delay_ctr, | |
338 | .dtr = delay_dtr, | |
339 | .map = delay_map, | |
340 | .presuspend = delay_presuspend, | |
341 | .resume = delay_resume, | |
342 | .status = delay_status, | |
af4874e0 | 343 | .iterate_devices = delay_iterate_devices, |
26b9f228 HM |
344 | }; |
345 | ||
346 | static int __init dm_delay_init(void) | |
347 | { | |
42065460 | 348 | int r; |
26b9f228 HM |
349 | |
350 | r = dm_register_target(&delay_target); | |
351 | if (r < 0) { | |
352 | DMERR("register failed %d", r); | |
353 | goto bad_register; | |
354 | } | |
355 | ||
356 | return 0; | |
357 | ||
358 | bad_register: | |
26b9f228 HM |
359 | return r; |
360 | } | |
361 | ||
362 | static void __exit dm_delay_exit(void) | |
363 | { | |
10d3bd09 | 364 | dm_unregister_target(&delay_target); |
26b9f228 HM |
365 | } |
366 | ||
367 | /* Module hooks */ | |
368 | module_init(dm_delay_init); | |
369 | module_exit(dm_delay_exit); | |
370 | ||
371 | MODULE_DESCRIPTION(DM_NAME " delay target"); | |
372 | MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>"); | |
373 | MODULE_LICENSE("GPL"); |