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*/ | |
f521f074 | 42 | struct work_struct trigger_event; |
a25eb944 | 43 | |
1da177e4 LT |
44 | struct stripe stripe[0]; |
45 | }; | |
46 | ||
a25eb944 BW |
47 | /* |
48 | * An event is triggered whenever a drive | |
49 | * drops out of a stripe volume. | |
50 | */ | |
51 | static void trigger_event(struct work_struct *work) | |
52 | { | |
f521f074 TH |
53 | struct stripe_c *sc = container_of(work, struct stripe_c, |
54 | trigger_event); | |
a25eb944 | 55 | dm_table_event(sc->ti->table); |
a25eb944 BW |
56 | } |
57 | ||
1da177e4 LT |
58 | static inline struct stripe_c *alloc_context(unsigned int stripes) |
59 | { | |
60 | size_t len; | |
61 | ||
d63a5ce3 MP |
62 | if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe), |
63 | stripes)) | |
1da177e4 LT |
64 | return NULL; |
65 | ||
66 | len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes); | |
67 | ||
68 | return kmalloc(len, GFP_KERNEL); | |
69 | } | |
70 | ||
71 | /* | |
72 | * Parse a single <dev> <sector> pair | |
73 | */ | |
74 | static int get_stripe(struct dm_target *ti, struct stripe_c *sc, | |
75 | unsigned int stripe, char **argv) | |
76 | { | |
4ee218cd | 77 | unsigned long long start; |
31998ef1 | 78 | char dummy; |
1da177e4 | 79 | |
31998ef1 | 80 | if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1) |
1da177e4 LT |
81 | return -EINVAL; |
82 | ||
8215d6ec | 83 | if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), |
1da177e4 LT |
84 | &sc->stripe[stripe].dev)) |
85 | return -ENXIO; | |
86 | ||
87 | sc->stripe[stripe].physical_start = start; | |
a25eb944 | 88 | |
1da177e4 LT |
89 | return 0; |
90 | } | |
91 | ||
92 | /* | |
93 | * Construct a striped mapping. | |
94 | * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+ | |
95 | */ | |
96 | static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
97 | { | |
98 | struct stripe_c *sc; | |
99 | sector_t width; | |
100 | uint32_t stripes; | |
101 | uint32_t chunk_size; | |
102 | char *end; | |
103 | int r; | |
104 | unsigned int i; | |
105 | ||
106 | if (argc < 2) { | |
72d94861 | 107 | ti->error = "Not enough arguments"; |
1da177e4 LT |
108 | return -EINVAL; |
109 | } | |
110 | ||
111 | stripes = simple_strtoul(argv[0], &end, 10); | |
781248c1 | 112 | if (!stripes || *end) { |
72d94861 | 113 | ti->error = "Invalid stripe count"; |
1da177e4 LT |
114 | return -EINVAL; |
115 | } | |
116 | ||
117 | chunk_size = simple_strtoul(argv[1], &end, 10); | |
118 | if (*end) { | |
72d94861 | 119 | ti->error = "Invalid chunk_size"; |
1da177e4 LT |
120 | return -EINVAL; |
121 | } | |
122 | ||
123 | /* | |
124 | * chunk_size is a power of two | |
125 | */ | |
6f3c3f0a | 126 | if (!is_power_of_2(chunk_size) || |
1da177e4 | 127 | (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) { |
72d94861 | 128 | ti->error = "Invalid chunk size"; |
1da177e4 LT |
129 | return -EINVAL; |
130 | } | |
131 | ||
a22c96c7 | 132 | if (ti->len & (chunk_size - 1)) { |
72d94861 | 133 | ti->error = "Target length not divisible by " |
8ba32fde KC |
134 | "chunk size"; |
135 | return -EINVAL; | |
136 | } | |
137 | ||
1da177e4 LT |
138 | width = ti->len; |
139 | if (sector_div(width, stripes)) { | |
72d94861 | 140 | ti->error = "Target length not divisible by " |
1da177e4 LT |
141 | "number of stripes"; |
142 | return -EINVAL; | |
143 | } | |
144 | ||
145 | /* | |
146 | * Do we have enough arguments for that many stripes ? | |
147 | */ | |
148 | if (argc != (2 + 2 * stripes)) { | |
72d94861 | 149 | ti->error = "Not enough destinations " |
1da177e4 LT |
150 | "specified"; |
151 | return -EINVAL; | |
152 | } | |
153 | ||
154 | sc = alloc_context(stripes); | |
155 | if (!sc) { | |
72d94861 | 156 | ti->error = "Memory allocation for striped context " |
1da177e4 LT |
157 | "failed"; |
158 | return -ENOMEM; | |
159 | } | |
160 | ||
f521f074 | 161 | INIT_WORK(&sc->trigger_event, trigger_event); |
a25eb944 BW |
162 | |
163 | /* Set pointer to dm target; used in trigger_event */ | |
164 | sc->ti = ti; | |
1da177e4 LT |
165 | sc->stripes = stripes; |
166 | sc->stripe_width = width; | |
c96053b7 MP |
167 | |
168 | if (stripes & (stripes - 1)) | |
169 | sc->stripes_shift = -1; | |
170 | else { | |
171 | sc->stripes_shift = ffs(stripes) - 1; | |
172 | sc->stripes_mask = ((sector_t) stripes) - 1; | |
173 | } | |
174 | ||
1da177e4 | 175 | ti->split_io = chunk_size; |
374bf7e7 | 176 | ti->num_flush_requests = stripes; |
7b76ec11 | 177 | ti->num_discard_requests = stripes; |
1da177e4 | 178 | |
c96053b7 | 179 | sc->chunk_shift = ffs(chunk_size) - 1; |
1da177e4 | 180 | sc->chunk_mask = ((sector_t) chunk_size) - 1; |
1da177e4 LT |
181 | |
182 | /* | |
183 | * Get the stripe destinations. | |
184 | */ | |
185 | for (i = 0; i < stripes; i++) { | |
186 | argv += 2; | |
187 | ||
188 | r = get_stripe(ti, sc, i, argv); | |
189 | if (r < 0) { | |
72d94861 | 190 | ti->error = "Couldn't parse stripe destination"; |
1da177e4 LT |
191 | while (i--) |
192 | dm_put_device(ti, sc->stripe[i].dev); | |
193 | kfree(sc); | |
194 | return r; | |
195 | } | |
a25eb944 | 196 | atomic_set(&(sc->stripe[i].error_count), 0); |
1da177e4 LT |
197 | } |
198 | ||
199 | ti->private = sc; | |
a25eb944 | 200 | |
1da177e4 LT |
201 | return 0; |
202 | } | |
203 | ||
204 | static void stripe_dtr(struct dm_target *ti) | |
205 | { | |
206 | unsigned int i; | |
207 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
208 | ||
209 | for (i = 0; i < sc->stripes; i++) | |
210 | dm_put_device(ti, sc->stripe[i].dev); | |
211 | ||
f521f074 | 212 | flush_work_sync(&sc->trigger_event); |
1da177e4 LT |
213 | kfree(sc); |
214 | } | |
215 | ||
65988525 MP |
216 | static void stripe_map_sector(struct stripe_c *sc, sector_t sector, |
217 | uint32_t *stripe, sector_t *result) | |
218 | { | |
219 | sector_t offset = dm_target_offset(sc->ti, sector); | |
220 | sector_t chunk = offset >> sc->chunk_shift; | |
221 | ||
c96053b7 MP |
222 | if (sc->stripes_shift < 0) |
223 | *stripe = sector_div(chunk, sc->stripes); | |
224 | else { | |
225 | *stripe = chunk & sc->stripes_mask; | |
226 | chunk >>= sc->stripes_shift; | |
227 | } | |
228 | ||
65988525 MP |
229 | *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask); |
230 | } | |
231 | ||
7b76ec11 MP |
232 | static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector, |
233 | uint32_t target_stripe, sector_t *result) | |
234 | { | |
235 | uint32_t stripe; | |
236 | ||
237 | stripe_map_sector(sc, sector, &stripe, result); | |
238 | if (stripe == target_stripe) | |
239 | return; | |
240 | *result &= ~sc->chunk_mask; /* round down */ | |
241 | if (target_stripe < stripe) | |
242 | *result += sc->chunk_mask + 1; /* next chunk */ | |
243 | } | |
244 | ||
245 | static int stripe_map_discard(struct stripe_c *sc, struct bio *bio, | |
246 | uint32_t target_stripe) | |
247 | { | |
248 | sector_t begin, end; | |
249 | ||
250 | stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin); | |
251 | stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio), | |
252 | target_stripe, &end); | |
253 | if (begin < end) { | |
254 | bio->bi_bdev = sc->stripe[target_stripe].dev->bdev; | |
255 | bio->bi_sector = begin + sc->stripe[target_stripe].physical_start; | |
256 | bio->bi_size = to_bytes(end - begin); | |
257 | return DM_MAPIO_REMAPPED; | |
258 | } else { | |
259 | /* The range doesn't map to the target stripe */ | |
260 | bio_endio(bio, 0); | |
261 | return DM_MAPIO_SUBMITTED; | |
262 | } | |
263 | } | |
264 | ||
1da177e4 LT |
265 | static int stripe_map(struct dm_target *ti, struct bio *bio, |
266 | union map_info *map_context) | |
267 | { | |
65988525 | 268 | struct stripe_c *sc = ti->private; |
374bf7e7 | 269 | uint32_t stripe; |
57cba5d3 | 270 | unsigned target_request_nr; |
1da177e4 | 271 | |
d87f4c14 | 272 | if (bio->bi_rw & REQ_FLUSH) { |
57cba5d3 MS |
273 | target_request_nr = map_context->target_request_nr; |
274 | BUG_ON(target_request_nr >= sc->stripes); | |
275 | bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev; | |
374bf7e7 MP |
276 | return DM_MAPIO_REMAPPED; |
277 | } | |
7b76ec11 MP |
278 | if (unlikely(bio->bi_rw & REQ_DISCARD)) { |
279 | target_request_nr = map_context->target_request_nr; | |
280 | BUG_ON(target_request_nr >= sc->stripes); | |
281 | return stripe_map_discard(sc, bio, target_request_nr); | |
282 | } | |
374bf7e7 | 283 | |
65988525 | 284 | stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector); |
1da177e4 | 285 | |
65988525 | 286 | bio->bi_sector += sc->stripe[stripe].physical_start; |
1da177e4 | 287 | bio->bi_bdev = sc->stripe[stripe].dev->bdev; |
65988525 | 288 | |
d2a7ad29 | 289 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
290 | } |
291 | ||
4f7f5c67 BW |
292 | /* |
293 | * Stripe status: | |
294 | * | |
295 | * INFO | |
296 | * #stripes [stripe_name <stripe_name>] [group word count] | |
297 | * [error count 'A|D' <error count 'A|D'>] | |
298 | * | |
299 | * TABLE | |
300 | * #stripes [stripe chunk size] | |
301 | * [stripe_name physical_start <stripe_name physical_start>] | |
302 | * | |
303 | */ | |
304 | ||
1da177e4 LT |
305 | static int stripe_status(struct dm_target *ti, |
306 | status_type_t type, char *result, unsigned int maxlen) | |
307 | { | |
308 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
4f7f5c67 | 309 | char buffer[sc->stripes + 1]; |
1da177e4 LT |
310 | unsigned int sz = 0; |
311 | unsigned int i; | |
312 | ||
313 | switch (type) { | |
314 | case STATUSTYPE_INFO: | |
4f7f5c67 BW |
315 | DMEMIT("%d ", sc->stripes); |
316 | for (i = 0; i < sc->stripes; i++) { | |
317 | DMEMIT("%s ", sc->stripe[i].dev->name); | |
318 | buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ? | |
319 | 'D' : 'A'; | |
320 | } | |
321 | buffer[i] = '\0'; | |
322 | DMEMIT("1 %s", buffer); | |
1da177e4 LT |
323 | break; |
324 | ||
325 | case STATUSTYPE_TABLE: | |
4ee218cd AM |
326 | DMEMIT("%d %llu", sc->stripes, |
327 | (unsigned long long)sc->chunk_mask + 1); | |
1da177e4 | 328 | for (i = 0; i < sc->stripes; i++) |
4ee218cd AM |
329 | DMEMIT(" %s %llu", sc->stripe[i].dev->name, |
330 | (unsigned long long)sc->stripe[i].physical_start); | |
1da177e4 LT |
331 | break; |
332 | } | |
333 | return 0; | |
334 | } | |
335 | ||
a25eb944 BW |
336 | static int stripe_end_io(struct dm_target *ti, struct bio *bio, |
337 | int error, union map_info *map_context) | |
338 | { | |
339 | unsigned i; | |
340 | char major_minor[16]; | |
341 | struct stripe_c *sc = ti->private; | |
342 | ||
343 | if (!error) | |
344 | return 0; /* I/O complete */ | |
345 | ||
7b6d91da | 346 | if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD)) |
a25eb944 BW |
347 | return error; |
348 | ||
349 | if (error == -EOPNOTSUPP) | |
350 | return error; | |
351 | ||
352 | memset(major_minor, 0, sizeof(major_minor)); | |
353 | sprintf(major_minor, "%d:%d", | |
f331c029 TH |
354 | MAJOR(disk_devt(bio->bi_bdev->bd_disk)), |
355 | MINOR(disk_devt(bio->bi_bdev->bd_disk))); | |
a25eb944 BW |
356 | |
357 | /* | |
358 | * Test to see which stripe drive triggered the event | |
359 | * and increment error count for all stripes on that device. | |
360 | * If the error count for a given device exceeds the threshold | |
361 | * value we will no longer trigger any further events. | |
362 | */ | |
363 | for (i = 0; i < sc->stripes; i++) | |
364 | if (!strcmp(sc->stripe[i].dev->name, major_minor)) { | |
365 | atomic_inc(&(sc->stripe[i].error_count)); | |
366 | if (atomic_read(&(sc->stripe[i].error_count)) < | |
367 | DM_IO_ERROR_THRESHOLD) | |
f521f074 | 368 | schedule_work(&sc->trigger_event); |
a25eb944 BW |
369 | } |
370 | ||
371 | return error; | |
372 | } | |
373 | ||
af4874e0 MS |
374 | static int stripe_iterate_devices(struct dm_target *ti, |
375 | iterate_devices_callout_fn fn, void *data) | |
376 | { | |
377 | struct stripe_c *sc = ti->private; | |
378 | int ret = 0; | |
379 | unsigned i = 0; | |
380 | ||
5dea271b | 381 | do { |
af4874e0 | 382 | ret = fn(ti, sc->stripe[i].dev, |
5dea271b MS |
383 | sc->stripe[i].physical_start, |
384 | sc->stripe_width, data); | |
385 | } while (!ret && ++i < sc->stripes); | |
af4874e0 MS |
386 | |
387 | return ret; | |
388 | } | |
389 | ||
40bea431 MS |
390 | static void stripe_io_hints(struct dm_target *ti, |
391 | struct queue_limits *limits) | |
392 | { | |
393 | struct stripe_c *sc = ti->private; | |
394 | unsigned chunk_size = (sc->chunk_mask + 1) << 9; | |
395 | ||
396 | blk_limits_io_min(limits, chunk_size); | |
3c5820c7 | 397 | blk_limits_io_opt(limits, chunk_size * sc->stripes); |
40bea431 MS |
398 | } |
399 | ||
29915202 MM |
400 | static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
401 | struct bio_vec *biovec, int max_size) | |
402 | { | |
403 | struct stripe_c *sc = ti->private; | |
404 | sector_t bvm_sector = bvm->bi_sector; | |
405 | uint32_t stripe; | |
406 | struct request_queue *q; | |
407 | ||
408 | stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector); | |
409 | ||
410 | q = bdev_get_queue(sc->stripe[stripe].dev->bdev); | |
411 | if (!q->merge_bvec_fn) | |
412 | return max_size; | |
413 | ||
414 | bvm->bi_bdev = sc->stripe[stripe].dev->bdev; | |
415 | bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector; | |
416 | ||
417 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
418 | } | |
419 | ||
1da177e4 LT |
420 | static struct target_type stripe_target = { |
421 | .name = "striped", | |
29915202 | 422 | .version = {1, 4, 0}, |
1da177e4 LT |
423 | .module = THIS_MODULE, |
424 | .ctr = stripe_ctr, | |
425 | .dtr = stripe_dtr, | |
426 | .map = stripe_map, | |
a25eb944 | 427 | .end_io = stripe_end_io, |
1da177e4 | 428 | .status = stripe_status, |
af4874e0 | 429 | .iterate_devices = stripe_iterate_devices, |
40bea431 | 430 | .io_hints = stripe_io_hints, |
29915202 | 431 | .merge = stripe_merge, |
1da177e4 LT |
432 | }; |
433 | ||
434 | int __init dm_stripe_init(void) | |
435 | { | |
436 | int r; | |
437 | ||
438 | r = dm_register_target(&stripe_target); | |
6edebdee | 439 | if (r < 0) { |
72d94861 | 440 | DMWARN("target registration failed"); |
6edebdee HM |
441 | return r; |
442 | } | |
1da177e4 LT |
443 | |
444 | return r; | |
445 | } | |
446 | ||
447 | void dm_stripe_exit(void) | |
448 | { | |
10d3bd09 | 449 | dm_unregister_target(&stripe_target); |
1da177e4 | 450 | } |