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 | ||
3876ac76 MP |
20 | struct delay_class { |
21 | struct dm_dev *dev; | |
22 | sector_t start; | |
23 | unsigned delay; | |
24 | unsigned ops; | |
25 | }; | |
26 | ||
26b9f228 HM |
27 | struct delay_c { |
28 | struct timer_list delay_timer; | |
ac818646 | 29 | struct mutex timer_lock; |
718822c1 | 30 | struct workqueue_struct *kdelayd_wq; |
26b9f228 HM |
31 | struct work_struct flush_expired_bios; |
32 | struct list_head delayed_bios; | |
33 | atomic_t may_delay; | |
26b9f228 | 34 | |
3876ac76 MP |
35 | struct delay_class read; |
36 | struct delay_class write; | |
cda6b5ab | 37 | struct delay_class flush; |
26b9f228 | 38 | |
3876ac76 | 39 | int argc; |
26b9f228 HM |
40 | }; |
41 | ||
028867ac | 42 | struct dm_delay_info { |
26b9f228 | 43 | struct delay_c *context; |
3876ac76 | 44 | struct delay_class *class; |
26b9f228 | 45 | struct list_head list; |
26b9f228 HM |
46 | unsigned long expires; |
47 | }; | |
48 | ||
49 | static DEFINE_MUTEX(delayed_bios_lock); | |
50 | ||
8376d3c1 | 51 | static void handle_delayed_timer(struct timer_list *t) |
26b9f228 | 52 | { |
8376d3c1 | 53 | struct delay_c *dc = from_timer(dc, t, delay_timer); |
26b9f228 | 54 | |
718822c1 | 55 | queue_work(dc->kdelayd_wq, &dc->flush_expired_bios); |
26b9f228 HM |
56 | } |
57 | ||
58 | static void queue_timeout(struct delay_c *dc, unsigned long expires) | |
59 | { | |
ac818646 | 60 | mutex_lock(&dc->timer_lock); |
26b9f228 HM |
61 | |
62 | if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires) | |
63 | mod_timer(&dc->delay_timer, expires); | |
64 | ||
ac818646 | 65 | mutex_unlock(&dc->timer_lock); |
26b9f228 HM |
66 | } |
67 | ||
68 | static 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 | ||
80 | static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all) | |
81 | { | |
028867ac | 82 | struct dm_delay_info *delayed, *next; |
26b9f228 | 83 | unsigned long next_expires = 0; |
3876ac76 | 84 | unsigned long start_timer = 0; |
051814c6 | 85 | struct bio_list flush_bios = { }; |
26b9f228 HM |
86 | |
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)) { | |
42065460 MP |
90 | struct bio *bio = dm_bio_from_per_bio_data(delayed, |
91 | sizeof(struct dm_delay_info)); | |
26b9f228 | 92 | list_del(&delayed->list); |
42065460 | 93 | bio_list_add(&flush_bios, bio); |
3876ac76 | 94 | delayed->class->ops--; |
26b9f228 HM |
95 | continue; |
96 | } | |
97 | ||
98 | if (!start_timer) { | |
99 | start_timer = 1; | |
100 | next_expires = delayed->expires; | |
101 | } else | |
102 | next_expires = min(next_expires, delayed->expires); | |
103 | } | |
26b9f228 HM |
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 | ||
3876ac76 MP |
120 | static void delay_dtr(struct dm_target *ti) |
121 | { | |
122 | struct delay_c *dc = ti->private; | |
123 | ||
124 | destroy_workqueue(dc->kdelayd_wq); | |
125 | ||
126 | if (dc->read.dev) | |
127 | dm_put_device(ti, dc->read.dev); | |
128 | if (dc->write.dev) | |
129 | dm_put_device(ti, dc->write.dev); | |
cda6b5ab MP |
130 | if (dc->flush.dev) |
131 | dm_put_device(ti, dc->flush.dev); | |
3876ac76 MP |
132 | |
133 | mutex_destroy(&dc->timer_lock); | |
134 | ||
135 | kfree(dc); | |
136 | } | |
137 | ||
138 | static int delay_class_ctr(struct dm_target *ti, struct delay_class *c, char **argv) | |
139 | { | |
140 | int ret; | |
141 | unsigned long long tmpll; | |
142 | char dummy; | |
143 | ||
ef87bfc2 | 144 | if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) { |
3876ac76 MP |
145 | ti->error = "Invalid device sector"; |
146 | return -EINVAL; | |
147 | } | |
148 | c->start = tmpll; | |
149 | ||
150 | if (sscanf(argv[2], "%u%c", &c->delay, &dummy) != 1) { | |
151 | ti->error = "Invalid delay"; | |
152 | return -EINVAL; | |
153 | } | |
154 | ||
155 | ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &c->dev); | |
156 | if (ret) { | |
157 | ti->error = "Device lookup failed"; | |
158 | return ret; | |
159 | } | |
160 | ||
161 | return 0; | |
162 | } | |
163 | ||
26b9f228 HM |
164 | /* |
165 | * Mapping parameters: | |
166 | * <device> <offset> <delay> [<write_device> <write_offset> <write_delay>] | |
167 | * | |
168 | * With separate write parameters, the first set is only used for reads. | |
f49e869a | 169 | * Offsets are specified in sectors. |
26b9f228 HM |
170 | * Delays are specified in milliseconds. |
171 | */ | |
172 | static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
173 | { | |
174 | struct delay_c *dc; | |
e80d1c80 | 175 | int ret; |
26b9f228 | 176 | |
cda6b5ab MP |
177 | if (argc != 3 && argc != 6 && argc != 9) { |
178 | ti->error = "Requires exactly 3, 6 or 9 arguments"; | |
26b9f228 HM |
179 | return -EINVAL; |
180 | } | |
181 | ||
3876ac76 | 182 | dc = kzalloc(sizeof(*dc), GFP_KERNEL); |
26b9f228 HM |
183 | if (!dc) { |
184 | ti->error = "Cannot allocate context"; | |
185 | return -ENOMEM; | |
186 | } | |
187 | ||
3876ac76 MP |
188 | ti->private = dc; |
189 | timer_setup(&dc->delay_timer, handle_delayed_timer, 0); | |
190 | INIT_WORK(&dc->flush_expired_bios, flush_expired_bios); | |
191 | INIT_LIST_HEAD(&dc->delayed_bios); | |
192 | mutex_init(&dc->timer_lock); | |
193 | atomic_set(&dc->may_delay, 1); | |
194 | dc->argc = argc; | |
26b9f228 | 195 | |
3876ac76 MP |
196 | ret = delay_class_ctr(ti, &dc->read, argv); |
197 | if (ret) | |
26b9f228 | 198 | goto bad; |
26b9f228 | 199 | |
3876ac76 MP |
200 | if (argc == 3) { |
201 | ret = delay_class_ctr(ti, &dc->write, argv); | |
cda6b5ab MP |
202 | if (ret) |
203 | goto bad; | |
204 | ret = delay_class_ctr(ti, &dc->flush, argv); | |
3876ac76 MP |
205 | if (ret) |
206 | goto bad; | |
26b9f228 | 207 | goto out; |
26b9f228 | 208 | } |
26b9f228 | 209 | |
3876ac76 MP |
210 | ret = delay_class_ctr(ti, &dc->write, argv + 3); |
211 | if (ret) | |
212 | goto bad; | |
cda6b5ab MP |
213 | if (argc == 6) { |
214 | ret = delay_class_ctr(ti, &dc->flush, argv + 3); | |
215 | if (ret) | |
216 | goto bad; | |
217 | goto out; | |
218 | } | |
219 | ||
220 | ret = delay_class_ctr(ti, &dc->flush, argv + 6); | |
221 | if (ret) | |
222 | goto bad; | |
26b9f228 HM |
223 | |
224 | out: | |
718822c1 MP |
225 | dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0); |
226 | if (!dc->kdelayd_wq) { | |
3876ac76 | 227 | ret = -EINVAL; |
718822c1 | 228 | DMERR("Couldn't start kdelayd"); |
3876ac76 | 229 | goto bad; |
718822c1 MP |
230 | } |
231 | ||
55a62eef AK |
232 | ti->num_flush_bios = 1; |
233 | ti->num_discard_bios = 1; | |
30187e1d | 234 | ti->per_io_data_size = sizeof(struct dm_delay_info); |
26b9f228 HM |
235 | return 0; |
236 | ||
237 | bad: | |
3876ac76 | 238 | delay_dtr(ti); |
e80d1c80 | 239 | return ret; |
26b9f228 HM |
240 | } |
241 | ||
3876ac76 | 242 | static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio) |
26b9f228 | 243 | { |
028867ac | 244 | struct dm_delay_info *delayed; |
26b9f228 HM |
245 | unsigned long expires = 0; |
246 | ||
3876ac76 | 247 | if (!c->delay || !atomic_read(&dc->may_delay)) |
340c9ec0 | 248 | return DM_MAPIO_REMAPPED; |
26b9f228 | 249 | |
42065460 | 250 | delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info)); |
26b9f228 HM |
251 | |
252 | delayed->context = dc; | |
3876ac76 | 253 | delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay); |
26b9f228 HM |
254 | |
255 | mutex_lock(&delayed_bios_lock); | |
3876ac76 | 256 | c->ops++; |
26b9f228 | 257 | list_add_tail(&delayed->list, &dc->delayed_bios); |
26b9f228 HM |
258 | mutex_unlock(&delayed_bios_lock); |
259 | ||
260 | queue_timeout(dc, expires); | |
261 | ||
340c9ec0 | 262 | return DM_MAPIO_SUBMITTED; |
26b9f228 HM |
263 | } |
264 | ||
265 | static void delay_presuspend(struct dm_target *ti) | |
266 | { | |
267 | struct delay_c *dc = ti->private; | |
268 | ||
269 | atomic_set(&dc->may_delay, 0); | |
270 | del_timer_sync(&dc->delay_timer); | |
271 | flush_bios(flush_delayed_bios(dc, 1)); | |
272 | } | |
273 | ||
274 | static void delay_resume(struct dm_target *ti) | |
275 | { | |
276 | struct delay_c *dc = ti->private; | |
277 | ||
278 | atomic_set(&dc->may_delay, 1); | |
279 | } | |
280 | ||
7de3ee57 | 281 | static int delay_map(struct dm_target *ti, struct bio *bio) |
26b9f228 HM |
282 | { |
283 | struct delay_c *dc = ti->private; | |
3876ac76 MP |
284 | struct delay_class *c; |
285 | struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info)); | |
26b9f228 | 286 | |
3876ac76 | 287 | if (bio_data_dir(bio) == WRITE) { |
cda6b5ab MP |
288 | if (unlikely(bio->bi_opf & REQ_PREFLUSH)) |
289 | c = &dc->flush; | |
290 | else | |
291 | c = &dc->write; | |
3876ac76 MP |
292 | } else { |
293 | c = &dc->read; | |
26b9f228 | 294 | } |
3876ac76 MP |
295 | delayed->class = c; |
296 | bio_set_dev(bio, c->dev->bdev); | |
297 | if (bio_sectors(bio)) | |
298 | bio->bi_iter.bi_sector = c->start + dm_target_offset(ti, bio->bi_iter.bi_sector); | |
26b9f228 | 299 | |
3876ac76 | 300 | return delay_bio(dc, c, bio); |
26b9f228 HM |
301 | } |
302 | ||
3876ac76 MP |
303 | #define DMEMIT_DELAY_CLASS(c) \ |
304 | DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay) | |
305 | ||
fd7c092e MP |
306 | static void delay_status(struct dm_target *ti, status_type_t type, |
307 | unsigned status_flags, char *result, unsigned maxlen) | |
26b9f228 HM |
308 | { |
309 | struct delay_c *dc = ti->private; | |
310 | int sz = 0; | |
311 | ||
312 | switch (type) { | |
313 | case STATUSTYPE_INFO: | |
cda6b5ab | 314 | DMEMIT("%u %u %u", dc->read.ops, dc->write.ops, dc->flush.ops); |
26b9f228 HM |
315 | break; |
316 | ||
317 | case STATUSTYPE_TABLE: | |
3876ac76 MP |
318 | DMEMIT_DELAY_CLASS(&dc->read); |
319 | if (dc->argc >= 6) { | |
320 | DMEMIT(" "); | |
321 | DMEMIT_DELAY_CLASS(&dc->write); | |
322 | } | |
cda6b5ab MP |
323 | if (dc->argc >= 9) { |
324 | DMEMIT(" "); | |
325 | DMEMIT_DELAY_CLASS(&dc->flush); | |
326 | } | |
26b9f228 HM |
327 | break; |
328 | } | |
26b9f228 HM |
329 | } |
330 | ||
af4874e0 MS |
331 | static int delay_iterate_devices(struct dm_target *ti, |
332 | iterate_devices_callout_fn fn, void *data) | |
333 | { | |
334 | struct delay_c *dc = ti->private; | |
335 | int ret = 0; | |
336 | ||
3876ac76 MP |
337 | ret = fn(ti, dc->read.dev, dc->read.start, ti->len, data); |
338 | if (ret) | |
339 | goto out; | |
340 | ret = fn(ti, dc->write.dev, dc->write.start, ti->len, data); | |
af4874e0 MS |
341 | if (ret) |
342 | goto out; | |
cda6b5ab MP |
343 | ret = fn(ti, dc->flush.dev, dc->flush.start, ti->len, data); |
344 | if (ret) | |
345 | goto out; | |
af4874e0 MS |
346 | |
347 | out: | |
348 | return ret; | |
349 | } | |
350 | ||
26b9f228 HM |
351 | static struct target_type delay_target = { |
352 | .name = "delay", | |
fd7c092e | 353 | .version = {1, 2, 1}, |
e2460f2a | 354 | .features = DM_TARGET_PASSES_INTEGRITY, |
26b9f228 HM |
355 | .module = THIS_MODULE, |
356 | .ctr = delay_ctr, | |
357 | .dtr = delay_dtr, | |
358 | .map = delay_map, | |
359 | .presuspend = delay_presuspend, | |
360 | .resume = delay_resume, | |
361 | .status = delay_status, | |
af4874e0 | 362 | .iterate_devices = delay_iterate_devices, |
26b9f228 HM |
363 | }; |
364 | ||
365 | static int __init dm_delay_init(void) | |
366 | { | |
42065460 | 367 | int r; |
26b9f228 HM |
368 | |
369 | r = dm_register_target(&delay_target); | |
370 | if (r < 0) { | |
371 | DMERR("register failed %d", r); | |
372 | goto bad_register; | |
373 | } | |
374 | ||
375 | return 0; | |
376 | ||
377 | bad_register: | |
26b9f228 HM |
378 | return r; |
379 | } | |
380 | ||
381 | static void __exit dm_delay_exit(void) | |
382 | { | |
10d3bd09 | 383 | dm_unregister_target(&delay_target); |
26b9f228 HM |
384 | } |
385 | ||
386 | /* Module hooks */ | |
387 | module_init(dm_delay_init); | |
388 | module_exit(dm_delay_exit); | |
389 | ||
390 | MODULE_DESCRIPTION(DM_NAME " delay target"); | |
391 | MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>"); | |
392 | MODULE_LICENSE("GPL"); |