Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001-2003 Sistina Software (UK) Limited. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
586e80e6 | 7 | #include <linux/device-mapper.h> |
1da177e4 LT |
8 | |
9 | #include <linux/module.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/bio.h> | |
13 | #include <linux/slab.h> | |
6f3c3f0a | 14 | #include <linux/log2.h> |
1da177e4 | 15 | |
72d94861 | 16 | #define DM_MSG_PREFIX "striped" |
a25eb944 | 17 | #define DM_IO_ERROR_THRESHOLD 15 |
72d94861 | 18 | |
1da177e4 LT |
19 | struct stripe { |
20 | struct dm_dev *dev; | |
21 | sector_t physical_start; | |
a25eb944 BW |
22 | |
23 | atomic_t error_count; | |
1da177e4 LT |
24 | }; |
25 | ||
26 | struct stripe_c { | |
27 | uint32_t stripes; | |
c96053b7 MP |
28 | int stripes_shift; |
29 | sector_t stripes_mask; | |
1da177e4 LT |
30 | |
31 | /* The size of this target / num. stripes */ | |
32 | sector_t stripe_width; | |
33 | ||
34 | /* stripe chunk size */ | |
35 | uint32_t chunk_shift; | |
36 | sector_t chunk_mask; | |
37 | ||
a25eb944 BW |
38 | /* Needed for handling events */ |
39 | struct dm_target *ti; | |
40 | ||
41 | /* Work struct used for triggering events*/ | |
42 | struct work_struct kstriped_ws; | |
43 | ||
1da177e4 LT |
44 | struct stripe stripe[0]; |
45 | }; | |
46 | ||
a25eb944 BW |
47 | static struct workqueue_struct *kstriped; |
48 | ||
49 | /* | |
50 | * An event is triggered whenever a drive | |
51 | * drops out of a stripe volume. | |
52 | */ | |
53 | static void trigger_event(struct work_struct *work) | |
54 | { | |
55 | struct stripe_c *sc = container_of(work, struct stripe_c, kstriped_ws); | |
56 | ||
57 | dm_table_event(sc->ti->table); | |
58 | ||
59 | } | |
60 | ||
1da177e4 LT |
61 | static inline struct stripe_c *alloc_context(unsigned int stripes) |
62 | { | |
63 | size_t len; | |
64 | ||
d63a5ce3 MP |
65 | if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe), |
66 | stripes)) | |
1da177e4 LT |
67 | return NULL; |
68 | ||
69 | len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes); | |
70 | ||
71 | return kmalloc(len, GFP_KERNEL); | |
72 | } | |
73 | ||
74 | /* | |
75 | * Parse a single <dev> <sector> pair | |
76 | */ | |
77 | static int get_stripe(struct dm_target *ti, struct stripe_c *sc, | |
78 | unsigned int stripe, char **argv) | |
79 | { | |
4ee218cd | 80 | unsigned long long start; |
1da177e4 | 81 | |
4ee218cd | 82 | if (sscanf(argv[1], "%llu", &start) != 1) |
1da177e4 LT |
83 | return -EINVAL; |
84 | ||
8215d6ec | 85 | if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), |
1da177e4 LT |
86 | &sc->stripe[stripe].dev)) |
87 | return -ENXIO; | |
88 | ||
89 | sc->stripe[stripe].physical_start = start; | |
a25eb944 | 90 | |
1da177e4 LT |
91 | return 0; |
92 | } | |
93 | ||
94 | /* | |
95 | * Construct a striped mapping. | |
96 | * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+ | |
97 | */ | |
98 | static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
99 | { | |
100 | struct stripe_c *sc; | |
101 | sector_t width; | |
102 | uint32_t stripes; | |
103 | uint32_t chunk_size; | |
104 | char *end; | |
105 | int r; | |
106 | unsigned int i; | |
107 | ||
108 | if (argc < 2) { | |
72d94861 | 109 | ti->error = "Not enough arguments"; |
1da177e4 LT |
110 | return -EINVAL; |
111 | } | |
112 | ||
113 | stripes = simple_strtoul(argv[0], &end, 10); | |
781248c1 | 114 | if (!stripes || *end) { |
72d94861 | 115 | ti->error = "Invalid stripe count"; |
1da177e4 LT |
116 | return -EINVAL; |
117 | } | |
118 | ||
119 | chunk_size = simple_strtoul(argv[1], &end, 10); | |
120 | if (*end) { | |
72d94861 | 121 | ti->error = "Invalid chunk_size"; |
1da177e4 LT |
122 | return -EINVAL; |
123 | } | |
124 | ||
125 | /* | |
126 | * chunk_size is a power of two | |
127 | */ | |
6f3c3f0a | 128 | if (!is_power_of_2(chunk_size) || |
1da177e4 | 129 | (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) { |
72d94861 | 130 | ti->error = "Invalid chunk size"; |
1da177e4 LT |
131 | return -EINVAL; |
132 | } | |
133 | ||
a22c96c7 | 134 | if (ti->len & (chunk_size - 1)) { |
72d94861 | 135 | ti->error = "Target length not divisible by " |
8ba32fde KC |
136 | "chunk size"; |
137 | return -EINVAL; | |
138 | } | |
139 | ||
1da177e4 LT |
140 | width = ti->len; |
141 | if (sector_div(width, stripes)) { | |
72d94861 | 142 | ti->error = "Target length not divisible by " |
1da177e4 LT |
143 | "number of stripes"; |
144 | return -EINVAL; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Do we have enough arguments for that many stripes ? | |
149 | */ | |
150 | if (argc != (2 + 2 * stripes)) { | |
72d94861 | 151 | ti->error = "Not enough destinations " |
1da177e4 LT |
152 | "specified"; |
153 | return -EINVAL; | |
154 | } | |
155 | ||
156 | sc = alloc_context(stripes); | |
157 | if (!sc) { | |
72d94861 | 158 | ti->error = "Memory allocation for striped context " |
1da177e4 LT |
159 | "failed"; |
160 | return -ENOMEM; | |
161 | } | |
162 | ||
a25eb944 BW |
163 | INIT_WORK(&sc->kstriped_ws, trigger_event); |
164 | ||
165 | /* Set pointer to dm target; used in trigger_event */ | |
166 | sc->ti = ti; | |
1da177e4 LT |
167 | sc->stripes = stripes; |
168 | sc->stripe_width = width; | |
c96053b7 MP |
169 | |
170 | if (stripes & (stripes - 1)) | |
171 | sc->stripes_shift = -1; | |
172 | else { | |
173 | sc->stripes_shift = ffs(stripes) - 1; | |
174 | sc->stripes_mask = ((sector_t) stripes) - 1; | |
175 | } | |
176 | ||
1da177e4 | 177 | ti->split_io = chunk_size; |
374bf7e7 | 178 | ti->num_flush_requests = stripes; |
7b76ec11 | 179 | ti->num_discard_requests = stripes; |
1da177e4 | 180 | |
c96053b7 | 181 | sc->chunk_shift = ffs(chunk_size) - 1; |
1da177e4 | 182 | sc->chunk_mask = ((sector_t) chunk_size) - 1; |
1da177e4 LT |
183 | |
184 | /* | |
185 | * Get the stripe destinations. | |
186 | */ | |
187 | for (i = 0; i < stripes; i++) { | |
188 | argv += 2; | |
189 | ||
190 | r = get_stripe(ti, sc, i, argv); | |
191 | if (r < 0) { | |
72d94861 | 192 | ti->error = "Couldn't parse stripe destination"; |
1da177e4 LT |
193 | while (i--) |
194 | dm_put_device(ti, sc->stripe[i].dev); | |
195 | kfree(sc); | |
196 | return r; | |
197 | } | |
a25eb944 | 198 | atomic_set(&(sc->stripe[i].error_count), 0); |
1da177e4 LT |
199 | } |
200 | ||
201 | ti->private = sc; | |
a25eb944 | 202 | |
1da177e4 LT |
203 | return 0; |
204 | } | |
205 | ||
206 | static void stripe_dtr(struct dm_target *ti) | |
207 | { | |
208 | unsigned int i; | |
209 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
210 | ||
211 | for (i = 0; i < sc->stripes; i++) | |
212 | dm_put_device(ti, sc->stripe[i].dev); | |
213 | ||
a25eb944 | 214 | flush_workqueue(kstriped); |
1da177e4 LT |
215 | kfree(sc); |
216 | } | |
217 | ||
65988525 MP |
218 | static void stripe_map_sector(struct stripe_c *sc, sector_t sector, |
219 | uint32_t *stripe, sector_t *result) | |
220 | { | |
221 | sector_t offset = dm_target_offset(sc->ti, sector); | |
222 | sector_t chunk = offset >> sc->chunk_shift; | |
223 | ||
c96053b7 MP |
224 | if (sc->stripes_shift < 0) |
225 | *stripe = sector_div(chunk, sc->stripes); | |
226 | else { | |
227 | *stripe = chunk & sc->stripes_mask; | |
228 | chunk >>= sc->stripes_shift; | |
229 | } | |
230 | ||
65988525 MP |
231 | *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask); |
232 | } | |
233 | ||
7b76ec11 MP |
234 | static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector, |
235 | uint32_t target_stripe, sector_t *result) | |
236 | { | |
237 | uint32_t stripe; | |
238 | ||
239 | stripe_map_sector(sc, sector, &stripe, result); | |
240 | if (stripe == target_stripe) | |
241 | return; | |
242 | *result &= ~sc->chunk_mask; /* round down */ | |
243 | if (target_stripe < stripe) | |
244 | *result += sc->chunk_mask + 1; /* next chunk */ | |
245 | } | |
246 | ||
247 | static int stripe_map_discard(struct stripe_c *sc, struct bio *bio, | |
248 | uint32_t target_stripe) | |
249 | { | |
250 | sector_t begin, end; | |
251 | ||
252 | stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin); | |
253 | stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio), | |
254 | target_stripe, &end); | |
255 | if (begin < end) { | |
256 | bio->bi_bdev = sc->stripe[target_stripe].dev->bdev; | |
257 | bio->bi_sector = begin + sc->stripe[target_stripe].physical_start; | |
258 | bio->bi_size = to_bytes(end - begin); | |
259 | return DM_MAPIO_REMAPPED; | |
260 | } else { | |
261 | /* The range doesn't map to the target stripe */ | |
262 | bio_endio(bio, 0); | |
263 | return DM_MAPIO_SUBMITTED; | |
264 | } | |
265 | } | |
266 | ||
1da177e4 LT |
267 | static int stripe_map(struct dm_target *ti, struct bio *bio, |
268 | union map_info *map_context) | |
269 | { | |
65988525 | 270 | struct stripe_c *sc = ti->private; |
374bf7e7 | 271 | uint32_t stripe; |
57cba5d3 | 272 | unsigned target_request_nr; |
1da177e4 | 273 | |
d87f4c14 | 274 | if (bio->bi_rw & REQ_FLUSH) { |
57cba5d3 MS |
275 | target_request_nr = map_context->target_request_nr; |
276 | BUG_ON(target_request_nr >= sc->stripes); | |
277 | bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev; | |
374bf7e7 MP |
278 | return DM_MAPIO_REMAPPED; |
279 | } | |
7b76ec11 MP |
280 | if (unlikely(bio->bi_rw & REQ_DISCARD)) { |
281 | target_request_nr = map_context->target_request_nr; | |
282 | BUG_ON(target_request_nr >= sc->stripes); | |
283 | return stripe_map_discard(sc, bio, target_request_nr); | |
284 | } | |
374bf7e7 | 285 | |
65988525 | 286 | stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector); |
1da177e4 | 287 | |
65988525 | 288 | bio->bi_sector += sc->stripe[stripe].physical_start; |
1da177e4 | 289 | bio->bi_bdev = sc->stripe[stripe].dev->bdev; |
65988525 | 290 | |
d2a7ad29 | 291 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
292 | } |
293 | ||
4f7f5c67 BW |
294 | /* |
295 | * Stripe status: | |
296 | * | |
297 | * INFO | |
298 | * #stripes [stripe_name <stripe_name>] [group word count] | |
299 | * [error count 'A|D' <error count 'A|D'>] | |
300 | * | |
301 | * TABLE | |
302 | * #stripes [stripe chunk size] | |
303 | * [stripe_name physical_start <stripe_name physical_start>] | |
304 | * | |
305 | */ | |
306 | ||
1da177e4 LT |
307 | static int stripe_status(struct dm_target *ti, |
308 | status_type_t type, char *result, unsigned int maxlen) | |
309 | { | |
310 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
4f7f5c67 | 311 | char buffer[sc->stripes + 1]; |
1da177e4 LT |
312 | unsigned int sz = 0; |
313 | unsigned int i; | |
314 | ||
315 | switch (type) { | |
316 | case STATUSTYPE_INFO: | |
4f7f5c67 BW |
317 | DMEMIT("%d ", sc->stripes); |
318 | for (i = 0; i < sc->stripes; i++) { | |
319 | DMEMIT("%s ", sc->stripe[i].dev->name); | |
320 | buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ? | |
321 | 'D' : 'A'; | |
322 | } | |
323 | buffer[i] = '\0'; | |
324 | DMEMIT("1 %s", buffer); | |
1da177e4 LT |
325 | break; |
326 | ||
327 | case STATUSTYPE_TABLE: | |
4ee218cd AM |
328 | DMEMIT("%d %llu", sc->stripes, |
329 | (unsigned long long)sc->chunk_mask + 1); | |
1da177e4 | 330 | for (i = 0; i < sc->stripes; i++) |
4ee218cd AM |
331 | DMEMIT(" %s %llu", sc->stripe[i].dev->name, |
332 | (unsigned long long)sc->stripe[i].physical_start); | |
1da177e4 LT |
333 | break; |
334 | } | |
335 | return 0; | |
336 | } | |
337 | ||
a25eb944 BW |
338 | static int stripe_end_io(struct dm_target *ti, struct bio *bio, |
339 | int error, union map_info *map_context) | |
340 | { | |
341 | unsigned i; | |
342 | char major_minor[16]; | |
343 | struct stripe_c *sc = ti->private; | |
344 | ||
345 | if (!error) | |
346 | return 0; /* I/O complete */ | |
347 | ||
7b6d91da | 348 | if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD)) |
a25eb944 BW |
349 | return error; |
350 | ||
351 | if (error == -EOPNOTSUPP) | |
352 | return error; | |
353 | ||
354 | memset(major_minor, 0, sizeof(major_minor)); | |
355 | sprintf(major_minor, "%d:%d", | |
f331c029 TH |
356 | MAJOR(disk_devt(bio->bi_bdev->bd_disk)), |
357 | MINOR(disk_devt(bio->bi_bdev->bd_disk))); | |
a25eb944 BW |
358 | |
359 | /* | |
360 | * Test to see which stripe drive triggered the event | |
361 | * and increment error count for all stripes on that device. | |
362 | * If the error count for a given device exceeds the threshold | |
363 | * value we will no longer trigger any further events. | |
364 | */ | |
365 | for (i = 0; i < sc->stripes; i++) | |
366 | if (!strcmp(sc->stripe[i].dev->name, major_minor)) { | |
367 | atomic_inc(&(sc->stripe[i].error_count)); | |
368 | if (atomic_read(&(sc->stripe[i].error_count)) < | |
369 | DM_IO_ERROR_THRESHOLD) | |
370 | queue_work(kstriped, &sc->kstriped_ws); | |
371 | } | |
372 | ||
373 | return error; | |
374 | } | |
375 | ||
af4874e0 MS |
376 | static int stripe_iterate_devices(struct dm_target *ti, |
377 | iterate_devices_callout_fn fn, void *data) | |
378 | { | |
379 | struct stripe_c *sc = ti->private; | |
380 | int ret = 0; | |
381 | unsigned i = 0; | |
382 | ||
5dea271b | 383 | do { |
af4874e0 | 384 | ret = fn(ti, sc->stripe[i].dev, |
5dea271b MS |
385 | sc->stripe[i].physical_start, |
386 | sc->stripe_width, data); | |
387 | } while (!ret && ++i < sc->stripes); | |
af4874e0 MS |
388 | |
389 | return ret; | |
390 | } | |
391 | ||
40bea431 MS |
392 | static void stripe_io_hints(struct dm_target *ti, |
393 | struct queue_limits *limits) | |
394 | { | |
395 | struct stripe_c *sc = ti->private; | |
396 | unsigned chunk_size = (sc->chunk_mask + 1) << 9; | |
397 | ||
398 | blk_limits_io_min(limits, chunk_size); | |
3c5820c7 | 399 | blk_limits_io_opt(limits, chunk_size * sc->stripes); |
40bea431 MS |
400 | } |
401 | ||
1da177e4 LT |
402 | static struct target_type stripe_target = { |
403 | .name = "striped", | |
40bea431 | 404 | .version = {1, 3, 0}, |
1da177e4 LT |
405 | .module = THIS_MODULE, |
406 | .ctr = stripe_ctr, | |
407 | .dtr = stripe_dtr, | |
408 | .map = stripe_map, | |
a25eb944 | 409 | .end_io = stripe_end_io, |
1da177e4 | 410 | .status = stripe_status, |
af4874e0 | 411 | .iterate_devices = stripe_iterate_devices, |
40bea431 | 412 | .io_hints = stripe_io_hints, |
1da177e4 LT |
413 | }; |
414 | ||
415 | int __init dm_stripe_init(void) | |
416 | { | |
417 | int r; | |
418 | ||
419 | r = dm_register_target(&stripe_target); | |
6edebdee | 420 | if (r < 0) { |
72d94861 | 421 | DMWARN("target registration failed"); |
6edebdee HM |
422 | return r; |
423 | } | |
1da177e4 | 424 | |
a25eb944 BW |
425 | kstriped = create_singlethread_workqueue("kstriped"); |
426 | if (!kstriped) { | |
427 | DMERR("failed to create workqueue kstriped"); | |
428 | dm_unregister_target(&stripe_target); | |
429 | return -ENOMEM; | |
430 | } | |
431 | ||
1da177e4 LT |
432 | return r; |
433 | } | |
434 | ||
435 | void dm_stripe_exit(void) | |
436 | { | |
10d3bd09 | 437 | dm_unregister_target(&stripe_target); |
a25eb944 BW |
438 | destroy_workqueue(kstriped); |
439 | ||
1da177e4 LT |
440 | return; |
441 | } |