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; |
e80d1c80 | 132 | int ret; |
26b9f228 HM |
133 | |
134 | if (argc != 3 && argc != 6) { | |
135 | ti->error = "requires exactly 3 or 6 arguments"; | |
136 | return -EINVAL; | |
137 | } | |
138 | ||
139 | dc = kmalloc(sizeof(*dc), GFP_KERNEL); | |
140 | if (!dc) { | |
141 | ti->error = "Cannot allocate context"; | |
142 | return -ENOMEM; | |
143 | } | |
144 | ||
145 | dc->reads = dc->writes = 0; | |
146 | ||
e80d1c80 | 147 | ret = -EINVAL; |
31998ef1 | 148 | if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) { |
26b9f228 HM |
149 | ti->error = "Invalid device sector"; |
150 | goto bad; | |
151 | } | |
152 | dc->start_read = tmpll; | |
153 | ||
31998ef1 | 154 | if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) { |
26b9f228 HM |
155 | ti->error = "Invalid delay"; |
156 | goto bad; | |
157 | } | |
158 | ||
e80d1c80 VG |
159 | ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), |
160 | &dc->dev_read); | |
161 | if (ret) { | |
26b9f228 HM |
162 | ti->error = "Device lookup failed"; |
163 | goto bad; | |
164 | } | |
165 | ||
e80d1c80 | 166 | ret = -EINVAL; |
2e64a0f9 DM |
167 | dc->dev_write = NULL; |
168 | if (argc == 3) | |
26b9f228 | 169 | goto out; |
26b9f228 | 170 | |
31998ef1 | 171 | if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) { |
26b9f228 | 172 | ti->error = "Invalid write device sector"; |
2e64a0f9 | 173 | goto bad_dev_read; |
26b9f228 HM |
174 | } |
175 | dc->start_write = tmpll; | |
176 | ||
31998ef1 | 177 | if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) { |
26b9f228 | 178 | ti->error = "Invalid write delay"; |
2e64a0f9 | 179 | goto bad_dev_read; |
26b9f228 HM |
180 | } |
181 | ||
e80d1c80 VG |
182 | ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), |
183 | &dc->dev_write); | |
184 | if (ret) { | |
26b9f228 | 185 | ti->error = "Write device lookup failed"; |
2e64a0f9 | 186 | goto bad_dev_read; |
26b9f228 HM |
187 | } |
188 | ||
189 | out: | |
e80d1c80 | 190 | ret = -EINVAL; |
718822c1 MP |
191 | dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0); |
192 | if (!dc->kdelayd_wq) { | |
193 | DMERR("Couldn't start kdelayd"); | |
194 | goto bad_queue; | |
195 | } | |
196 | ||
ac818646 | 197 | setup_timer(&dc->delay_timer, handle_delayed_timer, (unsigned long)dc); |
26b9f228 HM |
198 | |
199 | INIT_WORK(&dc->flush_expired_bios, flush_expired_bios); | |
200 | INIT_LIST_HEAD(&dc->delayed_bios); | |
ac818646 | 201 | mutex_init(&dc->timer_lock); |
26b9f228 HM |
202 | atomic_set(&dc->may_delay, 1); |
203 | ||
55a62eef AK |
204 | ti->num_flush_bios = 1; |
205 | ti->num_discard_bios = 1; | |
42065460 | 206 | ti->per_bio_data_size = sizeof(struct dm_delay_info); |
26b9f228 HM |
207 | ti->private = dc; |
208 | return 0; | |
209 | ||
718822c1 | 210 | bad_queue: |
2e64a0f9 DM |
211 | if (dc->dev_write) |
212 | dm_put_device(ti, dc->dev_write); | |
213 | bad_dev_read: | |
214 | dm_put_device(ti, dc->dev_read); | |
26b9f228 HM |
215 | bad: |
216 | kfree(dc); | |
e80d1c80 | 217 | return ret; |
26b9f228 HM |
218 | } |
219 | ||
220 | static void delay_dtr(struct dm_target *ti) | |
221 | { | |
222 | struct delay_c *dc = ti->private; | |
223 | ||
718822c1 | 224 | destroy_workqueue(dc->kdelayd_wq); |
26b9f228 HM |
225 | |
226 | dm_put_device(ti, dc->dev_read); | |
227 | ||
228 | if (dc->dev_write) | |
229 | dm_put_device(ti, dc->dev_write); | |
230 | ||
26b9f228 HM |
231 | kfree(dc); |
232 | } | |
233 | ||
234 | static int delay_bio(struct delay_c *dc, int delay, struct bio *bio) | |
235 | { | |
028867ac | 236 | struct dm_delay_info *delayed; |
26b9f228 HM |
237 | unsigned long expires = 0; |
238 | ||
239 | if (!delay || !atomic_read(&dc->may_delay)) | |
240 | return 1; | |
241 | ||
42065460 | 242 | delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info)); |
26b9f228 HM |
243 | |
244 | delayed->context = dc; | |
aca607ba | 245 | delayed->expires = expires = jiffies + msecs_to_jiffies(delay); |
26b9f228 HM |
246 | |
247 | mutex_lock(&delayed_bios_lock); | |
248 | ||
249 | if (bio_data_dir(bio) == WRITE) | |
250 | dc->writes++; | |
251 | else | |
252 | dc->reads++; | |
253 | ||
254 | list_add_tail(&delayed->list, &dc->delayed_bios); | |
255 | ||
256 | mutex_unlock(&delayed_bios_lock); | |
257 | ||
258 | queue_timeout(dc, expires); | |
259 | ||
260 | return 0; | |
261 | } | |
262 | ||
263 | static void delay_presuspend(struct dm_target *ti) | |
264 | { | |
265 | struct delay_c *dc = ti->private; | |
266 | ||
267 | atomic_set(&dc->may_delay, 0); | |
268 | del_timer_sync(&dc->delay_timer); | |
269 | flush_bios(flush_delayed_bios(dc, 1)); | |
270 | } | |
271 | ||
272 | static void delay_resume(struct dm_target *ti) | |
273 | { | |
274 | struct delay_c *dc = ti->private; | |
275 | ||
276 | atomic_set(&dc->may_delay, 1); | |
277 | } | |
278 | ||
7de3ee57 | 279 | static int delay_map(struct dm_target *ti, struct bio *bio) |
26b9f228 HM |
280 | { |
281 | struct delay_c *dc = ti->private; | |
282 | ||
283 | if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) { | |
284 | bio->bi_bdev = dc->dev_write->bdev; | |
c927259e | 285 | if (bio_sectors(bio)) |
4f024f37 KO |
286 | bio->bi_iter.bi_sector = dc->start_write + |
287 | dm_target_offset(ti, bio->bi_iter.bi_sector); | |
26b9f228 HM |
288 | |
289 | return delay_bio(dc, dc->write_delay, bio); | |
290 | } | |
291 | ||
292 | bio->bi_bdev = dc->dev_read->bdev; | |
4f024f37 KO |
293 | bio->bi_iter.bi_sector = dc->start_read + |
294 | dm_target_offset(ti, bio->bi_iter.bi_sector); | |
26b9f228 HM |
295 | |
296 | return delay_bio(dc, dc->read_delay, bio); | |
297 | } | |
298 | ||
fd7c092e MP |
299 | static void delay_status(struct dm_target *ti, status_type_t type, |
300 | unsigned status_flags, char *result, unsigned maxlen) | |
26b9f228 HM |
301 | { |
302 | struct delay_c *dc = ti->private; | |
303 | int sz = 0; | |
304 | ||
305 | switch (type) { | |
306 | case STATUSTYPE_INFO: | |
307 | DMEMIT("%u %u", dc->reads, dc->writes); | |
308 | break; | |
309 | ||
310 | case STATUSTYPE_TABLE: | |
311 | DMEMIT("%s %llu %u", dc->dev_read->name, | |
312 | (unsigned long long) dc->start_read, | |
313 | dc->read_delay); | |
314 | if (dc->dev_write) | |
79662d1e | 315 | DMEMIT(" %s %llu %u", dc->dev_write->name, |
26b9f228 HM |
316 | (unsigned long long) dc->start_write, |
317 | dc->write_delay); | |
318 | break; | |
319 | } | |
26b9f228 HM |
320 | } |
321 | ||
af4874e0 MS |
322 | static 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 | ||
5dea271b | 328 | ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data); |
af4874e0 MS |
329 | if (ret) |
330 | goto out; | |
331 | ||
332 | if (dc->dev_write) | |
5dea271b | 333 | ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data); |
af4874e0 MS |
334 | |
335 | out: | |
336 | return ret; | |
337 | } | |
338 | ||
26b9f228 HM |
339 | static struct target_type delay_target = { |
340 | .name = "delay", | |
fd7c092e | 341 | .version = {1, 2, 1}, |
26b9f228 HM |
342 | .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, | |
af4874e0 | 349 | .iterate_devices = delay_iterate_devices, |
26b9f228 HM |
350 | }; |
351 | ||
352 | static int __init dm_delay_init(void) | |
353 | { | |
42065460 | 354 | int r; |
26b9f228 HM |
355 | |
356 | r = dm_register_target(&delay_target); | |
357 | if (r < 0) { | |
358 | DMERR("register failed %d", r); | |
359 | goto bad_register; | |
360 | } | |
361 | ||
362 | return 0; | |
363 | ||
364 | bad_register: | |
26b9f228 HM |
365 | return r; |
366 | } | |
367 | ||
368 | static void __exit dm_delay_exit(void) | |
369 | { | |
10d3bd09 | 370 | dm_unregister_target(&delay_target); |
26b9f228 HM |
371 | } |
372 | ||
373 | /* Module hooks */ | |
374 | module_init(dm_delay_init); | |
375 | module_exit(dm_delay_exit); | |
376 | ||
377 | MODULE_DESCRIPTION(DM_NAME " delay target"); | |
378 | MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>"); | |
379 | MODULE_LICENSE("GPL"); |