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 | 28 | int stripes_shift; |
1da177e4 LT |
29 | |
30 | /* The size of this target / num. stripes */ | |
31 | sector_t stripe_width; | |
32 | ||
eb850de6 | 33 | uint32_t chunk_size; |
1da177e4 | 34 | |
a25eb944 BW |
35 | /* Needed for handling events */ |
36 | struct dm_target *ti; | |
37 | ||
38 | /* Work struct used for triggering events*/ | |
f521f074 | 39 | struct work_struct trigger_event; |
a25eb944 | 40 | |
1da177e4 LT |
41 | struct stripe stripe[0]; |
42 | }; | |
43 | ||
a25eb944 BW |
44 | /* |
45 | * An event is triggered whenever a drive | |
46 | * drops out of a stripe volume. | |
47 | */ | |
48 | static void trigger_event(struct work_struct *work) | |
49 | { | |
f521f074 TH |
50 | struct stripe_c *sc = container_of(work, struct stripe_c, |
51 | trigger_event); | |
a25eb944 | 52 | dm_table_event(sc->ti->table); |
a25eb944 BW |
53 | } |
54 | ||
1da177e4 LT |
55 | static inline struct stripe_c *alloc_context(unsigned int stripes) |
56 | { | |
57 | size_t len; | |
58 | ||
d63a5ce3 MP |
59 | if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe), |
60 | stripes)) | |
1da177e4 LT |
61 | return NULL; |
62 | ||
63 | len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes); | |
64 | ||
65 | return kmalloc(len, GFP_KERNEL); | |
66 | } | |
67 | ||
68 | /* | |
69 | * Parse a single <dev> <sector> pair | |
70 | */ | |
71 | static int get_stripe(struct dm_target *ti, struct stripe_c *sc, | |
72 | unsigned int stripe, char **argv) | |
73 | { | |
4ee218cd | 74 | unsigned long long start; |
31998ef1 | 75 | char dummy; |
1da177e4 | 76 | |
31998ef1 | 77 | if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1) |
1da177e4 LT |
78 | return -EINVAL; |
79 | ||
8215d6ec | 80 | if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), |
1da177e4 LT |
81 | &sc->stripe[stripe].dev)) |
82 | return -ENXIO; | |
83 | ||
84 | sc->stripe[stripe].physical_start = start; | |
a25eb944 | 85 | |
1da177e4 LT |
86 | return 0; |
87 | } | |
88 | ||
89 | /* | |
90 | * Construct a striped mapping. | |
eb850de6 | 91 | * <number of stripes> <chunk size> [<dev_path> <offset>]+ |
1da177e4 LT |
92 | */ |
93 | static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
94 | { | |
95 | struct stripe_c *sc; | |
96 | sector_t width; | |
97 | uint32_t stripes; | |
98 | uint32_t chunk_size; | |
1da177e4 LT |
99 | int r; |
100 | unsigned int i; | |
101 | ||
102 | if (argc < 2) { | |
72d94861 | 103 | ti->error = "Not enough arguments"; |
1da177e4 LT |
104 | return -EINVAL; |
105 | } | |
106 | ||
1a66a08a | 107 | if (kstrtouint(argv[0], 10, &stripes) || !stripes) { |
72d94861 | 108 | ti->error = "Invalid stripe count"; |
1da177e4 LT |
109 | return -EINVAL; |
110 | } | |
111 | ||
eb850de6 | 112 | if (kstrtouint(argv[1], 10, &chunk_size) || |
1da177e4 | 113 | (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) { |
eb850de6 | 114 | ti->error = "Invalid chunk_size"; |
1da177e4 LT |
115 | return -EINVAL; |
116 | } | |
117 | ||
eb850de6 MS |
118 | width = ti->len; |
119 | if (sector_div(width, chunk_size)) { | |
72d94861 | 120 | ti->error = "Target length not divisible by " |
8ba32fde KC |
121 | "chunk size"; |
122 | return -EINVAL; | |
123 | } | |
124 | ||
1da177e4 | 125 | if (sector_div(width, stripes)) { |
72d94861 | 126 | ti->error = "Target length not divisible by " |
1da177e4 LT |
127 | "number of stripes"; |
128 | return -EINVAL; | |
129 | } | |
130 | ||
131 | /* | |
132 | * Do we have enough arguments for that many stripes ? | |
133 | */ | |
134 | if (argc != (2 + 2 * stripes)) { | |
72d94861 | 135 | ti->error = "Not enough destinations " |
1da177e4 LT |
136 | "specified"; |
137 | return -EINVAL; | |
138 | } | |
139 | ||
140 | sc = alloc_context(stripes); | |
141 | if (!sc) { | |
72d94861 | 142 | ti->error = "Memory allocation for striped context " |
1da177e4 LT |
143 | "failed"; |
144 | return -ENOMEM; | |
145 | } | |
146 | ||
f521f074 | 147 | INIT_WORK(&sc->trigger_event, trigger_event); |
a25eb944 BW |
148 | |
149 | /* Set pointer to dm target; used in trigger_event */ | |
150 | sc->ti = ti; | |
1da177e4 LT |
151 | sc->stripes = stripes; |
152 | sc->stripe_width = width; | |
c96053b7 MP |
153 | |
154 | if (stripes & (stripes - 1)) | |
155 | sc->stripes_shift = -1; | |
1df05483 MP |
156 | else |
157 | sc->stripes_shift = __ffs(stripes); | |
c96053b7 | 158 | |
542f9038 MS |
159 | r = dm_set_target_max_io_len(ti, chunk_size); |
160 | if (r) | |
161 | return r; | |
162 | ||
374bf7e7 | 163 | ti->num_flush_requests = stripes; |
7b76ec11 | 164 | ti->num_discard_requests = stripes; |
1da177e4 | 165 | |
eb850de6 | 166 | sc->chunk_size = chunk_size; |
1da177e4 LT |
167 | |
168 | /* | |
169 | * Get the stripe destinations. | |
170 | */ | |
171 | for (i = 0; i < stripes; i++) { | |
172 | argv += 2; | |
173 | ||
174 | r = get_stripe(ti, sc, i, argv); | |
175 | if (r < 0) { | |
72d94861 | 176 | ti->error = "Couldn't parse stripe destination"; |
1da177e4 LT |
177 | while (i--) |
178 | dm_put_device(ti, sc->stripe[i].dev); | |
179 | kfree(sc); | |
180 | return r; | |
181 | } | |
a25eb944 | 182 | atomic_set(&(sc->stripe[i].error_count), 0); |
1da177e4 LT |
183 | } |
184 | ||
185 | ti->private = sc; | |
a25eb944 | 186 | |
1da177e4 LT |
187 | return 0; |
188 | } | |
189 | ||
190 | static void stripe_dtr(struct dm_target *ti) | |
191 | { | |
192 | unsigned int i; | |
193 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
194 | ||
195 | for (i = 0; i < sc->stripes; i++) | |
196 | dm_put_device(ti, sc->stripe[i].dev); | |
197 | ||
f521f074 | 198 | flush_work_sync(&sc->trigger_event); |
1da177e4 LT |
199 | kfree(sc); |
200 | } | |
201 | ||
65988525 MP |
202 | static void stripe_map_sector(struct stripe_c *sc, sector_t sector, |
203 | uint32_t *stripe, sector_t *result) | |
204 | { | |
eb850de6 MS |
205 | sector_t chunk = dm_target_offset(sc->ti, sector); |
206 | sector_t chunk_offset = sector_div(chunk, sc->chunk_size); | |
65988525 | 207 | |
c96053b7 MP |
208 | if (sc->stripes_shift < 0) |
209 | *stripe = sector_div(chunk, sc->stripes); | |
210 | else { | |
1df05483 | 211 | *stripe = chunk & (sc->stripes - 1); |
c96053b7 MP |
212 | chunk >>= sc->stripes_shift; |
213 | } | |
214 | ||
eb850de6 | 215 | *result = (chunk * sc->chunk_size) + chunk_offset; |
65988525 MP |
216 | } |
217 | ||
7b76ec11 MP |
218 | static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector, |
219 | uint32_t target_stripe, sector_t *result) | |
220 | { | |
221 | uint32_t stripe; | |
222 | ||
223 | stripe_map_sector(sc, sector, &stripe, result); | |
224 | if (stripe == target_stripe) | |
225 | return; | |
eb850de6 MS |
226 | |
227 | /* round down */ | |
228 | sector = *result; | |
229 | *result -= sector_div(sector, sc->chunk_size); | |
230 | ||
7b76ec11 | 231 | if (target_stripe < stripe) |
eb850de6 | 232 | *result += sc->chunk_size; /* next chunk */ |
7b76ec11 MP |
233 | } |
234 | ||
235 | static int stripe_map_discard(struct stripe_c *sc, struct bio *bio, | |
236 | uint32_t target_stripe) | |
237 | { | |
238 | sector_t begin, end; | |
239 | ||
240 | stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin); | |
241 | stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio), | |
242 | target_stripe, &end); | |
243 | if (begin < end) { | |
244 | bio->bi_bdev = sc->stripe[target_stripe].dev->bdev; | |
245 | bio->bi_sector = begin + sc->stripe[target_stripe].physical_start; | |
246 | bio->bi_size = to_bytes(end - begin); | |
247 | return DM_MAPIO_REMAPPED; | |
248 | } else { | |
249 | /* The range doesn't map to the target stripe */ | |
250 | bio_endio(bio, 0); | |
251 | return DM_MAPIO_SUBMITTED; | |
252 | } | |
253 | } | |
254 | ||
1da177e4 LT |
255 | static int stripe_map(struct dm_target *ti, struct bio *bio, |
256 | union map_info *map_context) | |
257 | { | |
65988525 | 258 | struct stripe_c *sc = ti->private; |
374bf7e7 | 259 | uint32_t stripe; |
57cba5d3 | 260 | unsigned target_request_nr; |
1da177e4 | 261 | |
d87f4c14 | 262 | if (bio->bi_rw & REQ_FLUSH) { |
57cba5d3 MS |
263 | target_request_nr = map_context->target_request_nr; |
264 | BUG_ON(target_request_nr >= sc->stripes); | |
265 | bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev; | |
374bf7e7 MP |
266 | return DM_MAPIO_REMAPPED; |
267 | } | |
7b76ec11 MP |
268 | if (unlikely(bio->bi_rw & REQ_DISCARD)) { |
269 | target_request_nr = map_context->target_request_nr; | |
270 | BUG_ON(target_request_nr >= sc->stripes); | |
271 | return stripe_map_discard(sc, bio, target_request_nr); | |
272 | } | |
374bf7e7 | 273 | |
65988525 | 274 | stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector); |
1da177e4 | 275 | |
65988525 | 276 | bio->bi_sector += sc->stripe[stripe].physical_start; |
1da177e4 | 277 | bio->bi_bdev = sc->stripe[stripe].dev->bdev; |
65988525 | 278 | |
d2a7ad29 | 279 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
280 | } |
281 | ||
4f7f5c67 BW |
282 | /* |
283 | * Stripe status: | |
284 | * | |
285 | * INFO | |
286 | * #stripes [stripe_name <stripe_name>] [group word count] | |
287 | * [error count 'A|D' <error count 'A|D'>] | |
288 | * | |
289 | * TABLE | |
290 | * #stripes [stripe chunk size] | |
291 | * [stripe_name physical_start <stripe_name physical_start>] | |
292 | * | |
293 | */ | |
294 | ||
1da177e4 LT |
295 | static int stripe_status(struct dm_target *ti, |
296 | status_type_t type, char *result, unsigned int maxlen) | |
297 | { | |
298 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
4f7f5c67 | 299 | char buffer[sc->stripes + 1]; |
1da177e4 LT |
300 | unsigned int sz = 0; |
301 | unsigned int i; | |
302 | ||
303 | switch (type) { | |
304 | case STATUSTYPE_INFO: | |
4f7f5c67 BW |
305 | DMEMIT("%d ", sc->stripes); |
306 | for (i = 0; i < sc->stripes; i++) { | |
307 | DMEMIT("%s ", sc->stripe[i].dev->name); | |
308 | buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ? | |
309 | 'D' : 'A'; | |
310 | } | |
311 | buffer[i] = '\0'; | |
312 | DMEMIT("1 %s", buffer); | |
1da177e4 LT |
313 | break; |
314 | ||
315 | case STATUSTYPE_TABLE: | |
4ee218cd | 316 | DMEMIT("%d %llu", sc->stripes, |
eb850de6 | 317 | (unsigned long long)sc->chunk_size); |
1da177e4 | 318 | for (i = 0; i < sc->stripes; i++) |
4ee218cd AM |
319 | DMEMIT(" %s %llu", sc->stripe[i].dev->name, |
320 | (unsigned long long)sc->stripe[i].physical_start); | |
1da177e4 LT |
321 | break; |
322 | } | |
323 | return 0; | |
324 | } | |
325 | ||
a25eb944 BW |
326 | static int stripe_end_io(struct dm_target *ti, struct bio *bio, |
327 | int error, union map_info *map_context) | |
328 | { | |
329 | unsigned i; | |
330 | char major_minor[16]; | |
331 | struct stripe_c *sc = ti->private; | |
332 | ||
333 | if (!error) | |
334 | return 0; /* I/O complete */ | |
335 | ||
7b6d91da | 336 | if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD)) |
a25eb944 BW |
337 | return error; |
338 | ||
339 | if (error == -EOPNOTSUPP) | |
340 | return error; | |
341 | ||
342 | memset(major_minor, 0, sizeof(major_minor)); | |
343 | sprintf(major_minor, "%d:%d", | |
f331c029 TH |
344 | MAJOR(disk_devt(bio->bi_bdev->bd_disk)), |
345 | MINOR(disk_devt(bio->bi_bdev->bd_disk))); | |
a25eb944 BW |
346 | |
347 | /* | |
348 | * Test to see which stripe drive triggered the event | |
349 | * and increment error count for all stripes on that device. | |
350 | * If the error count for a given device exceeds the threshold | |
351 | * value we will no longer trigger any further events. | |
352 | */ | |
353 | for (i = 0; i < sc->stripes; i++) | |
354 | if (!strcmp(sc->stripe[i].dev->name, major_minor)) { | |
355 | atomic_inc(&(sc->stripe[i].error_count)); | |
356 | if (atomic_read(&(sc->stripe[i].error_count)) < | |
357 | DM_IO_ERROR_THRESHOLD) | |
f521f074 | 358 | schedule_work(&sc->trigger_event); |
a25eb944 BW |
359 | } |
360 | ||
361 | return error; | |
362 | } | |
363 | ||
af4874e0 MS |
364 | static int stripe_iterate_devices(struct dm_target *ti, |
365 | iterate_devices_callout_fn fn, void *data) | |
366 | { | |
367 | struct stripe_c *sc = ti->private; | |
368 | int ret = 0; | |
369 | unsigned i = 0; | |
370 | ||
5dea271b | 371 | do { |
af4874e0 | 372 | ret = fn(ti, sc->stripe[i].dev, |
5dea271b MS |
373 | sc->stripe[i].physical_start, |
374 | sc->stripe_width, data); | |
375 | } while (!ret && ++i < sc->stripes); | |
af4874e0 MS |
376 | |
377 | return ret; | |
378 | } | |
379 | ||
40bea431 MS |
380 | static void stripe_io_hints(struct dm_target *ti, |
381 | struct queue_limits *limits) | |
382 | { | |
383 | struct stripe_c *sc = ti->private; | |
eb850de6 | 384 | unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT; |
40bea431 MS |
385 | |
386 | blk_limits_io_min(limits, chunk_size); | |
3c5820c7 | 387 | blk_limits_io_opt(limits, chunk_size * sc->stripes); |
40bea431 MS |
388 | } |
389 | ||
29915202 MM |
390 | static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
391 | struct bio_vec *biovec, int max_size) | |
392 | { | |
393 | struct stripe_c *sc = ti->private; | |
394 | sector_t bvm_sector = bvm->bi_sector; | |
395 | uint32_t stripe; | |
396 | struct request_queue *q; | |
397 | ||
398 | stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector); | |
399 | ||
400 | q = bdev_get_queue(sc->stripe[stripe].dev->bdev); | |
401 | if (!q->merge_bvec_fn) | |
402 | return max_size; | |
403 | ||
404 | bvm->bi_bdev = sc->stripe[stripe].dev->bdev; | |
405 | bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector; | |
406 | ||
407 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
408 | } | |
409 | ||
1da177e4 LT |
410 | static struct target_type stripe_target = { |
411 | .name = "striped", | |
eb850de6 | 412 | .version = {1, 5, 0}, |
1da177e4 LT |
413 | .module = THIS_MODULE, |
414 | .ctr = stripe_ctr, | |
415 | .dtr = stripe_dtr, | |
416 | .map = stripe_map, | |
a25eb944 | 417 | .end_io = stripe_end_io, |
1da177e4 | 418 | .status = stripe_status, |
af4874e0 | 419 | .iterate_devices = stripe_iterate_devices, |
40bea431 | 420 | .io_hints = stripe_io_hints, |
29915202 | 421 | .merge = stripe_merge, |
1da177e4 LT |
422 | }; |
423 | ||
424 | int __init dm_stripe_init(void) | |
425 | { | |
426 | int r; | |
427 | ||
428 | r = dm_register_target(&stripe_target); | |
6edebdee | 429 | if (r < 0) { |
72d94861 | 430 | DMWARN("target registration failed"); |
6edebdee HM |
431 | return r; |
432 | } | |
1da177e4 LT |
433 | |
434 | return r; | |
435 | } | |
436 | ||
437 | void dm_stripe_exit(void) | |
438 | { | |
10d3bd09 | 439 | dm_unregister_target(&stripe_target); |
1da177e4 | 440 | } |