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1/*
2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm.h"
8#include <linux/device-mapper.h>
9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/blkdev.h>
13#include <linux/bio.h>
14#include <linux/dax.h>
15#include <linux/slab.h>
16#include <linux/log2.h>
17
18#define DM_MSG_PREFIX "striped"
19#define DM_IO_ERROR_THRESHOLD 15
20
21struct stripe {
22 struct dm_dev *dev;
23 sector_t physical_start;
24
25 atomic_t error_count;
26};
27
28struct stripe_c {
29 uint32_t stripes;
30 int stripes_shift;
31
32 /* The size of this target / num. stripes */
33 sector_t stripe_width;
34
35 uint32_t chunk_size;
36 int chunk_size_shift;
37
38 /* Needed for handling events */
39 struct dm_target *ti;
40
41 /* Work struct used for triggering events*/
42 struct work_struct trigger_event;
43
44 struct stripe stripe[];
45};
46
47/*
48 * An event is triggered whenever a drive
49 * drops out of a stripe volume.
50 */
51static void trigger_event(struct work_struct *work)
52{
53 struct stripe_c *sc = container_of(work, struct stripe_c,
54 trigger_event);
55 dm_table_event(sc->ti->table);
56}
57
58/*
59 * Parse a single <dev> <sector> pair
60 */
61static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
62 unsigned int stripe, char **argv)
63{
64 unsigned long long start;
65 char dummy;
66 int ret;
67
68 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
69 return -EINVAL;
70
71 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
72 &sc->stripe[stripe].dev);
73 if (ret)
74 return ret;
75
76 sc->stripe[stripe].physical_start = start;
77
78 return 0;
79}
80
81/*
82 * Construct a striped mapping.
83 * <number of stripes> <chunk size> [<dev_path> <offset>]+
84 */
85static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
86{
87 struct stripe_c *sc;
88 sector_t width, tmp_len;
89 uint32_t stripes;
90 uint32_t chunk_size;
91 int r;
92 unsigned int i;
93
94 if (argc < 2) {
95 ti->error = "Not enough arguments";
96 return -EINVAL;
97 }
98
99 if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
100 ti->error = "Invalid stripe count";
101 return -EINVAL;
102 }
103
104 if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
105 ti->error = "Invalid chunk_size";
106 return -EINVAL;
107 }
108
109 width = ti->len;
110 if (sector_div(width, stripes)) {
111 ti->error = "Target length not divisible by "
112 "number of stripes";
113 return -EINVAL;
114 }
115
116 tmp_len = width;
117 if (sector_div(tmp_len, chunk_size)) {
118 ti->error = "Target length not divisible by "
119 "chunk size";
120 return -EINVAL;
121 }
122
123 /*
124 * Do we have enough arguments for that many stripes ?
125 */
126 if (argc != (2 + 2 * stripes)) {
127 ti->error = "Not enough destinations "
128 "specified";
129 return -EINVAL;
130 }
131
132 sc = kmalloc(struct_size(sc, stripe, stripes), GFP_KERNEL);
133 if (!sc) {
134 ti->error = "Memory allocation for striped context "
135 "failed";
136 return -ENOMEM;
137 }
138
139 INIT_WORK(&sc->trigger_event, trigger_event);
140
141 /* Set pointer to dm target; used in trigger_event */
142 sc->ti = ti;
143 sc->stripes = stripes;
144 sc->stripe_width = width;
145
146 if (stripes & (stripes - 1))
147 sc->stripes_shift = -1;
148 else
149 sc->stripes_shift = __ffs(stripes);
150
151 r = dm_set_target_max_io_len(ti, chunk_size);
152 if (r) {
153 kfree(sc);
154 return r;
155 }
156
157 ti->num_flush_bios = stripes;
158 ti->num_discard_bios = stripes;
159 ti->num_secure_erase_bios = stripes;
160 ti->num_write_same_bios = stripes;
161 ti->num_write_zeroes_bios = stripes;
162
163 sc->chunk_size = chunk_size;
164 if (chunk_size & (chunk_size - 1))
165 sc->chunk_size_shift = -1;
166 else
167 sc->chunk_size_shift = __ffs(chunk_size);
168
169 /*
170 * Get the stripe destinations.
171 */
172 for (i = 0; i < stripes; i++) {
173 argv += 2;
174
175 r = get_stripe(ti, sc, i, argv);
176 if (r < 0) {
177 ti->error = "Couldn't parse stripe destination";
178 while (i--)
179 dm_put_device(ti, sc->stripe[i].dev);
180 kfree(sc);
181 return r;
182 }
183 atomic_set(&(sc->stripe[i].error_count), 0);
184 }
185
186 ti->private = sc;
187
188 return 0;
189}
190
191static void stripe_dtr(struct dm_target *ti)
192{
193 unsigned int i;
194 struct stripe_c *sc = (struct stripe_c *) ti->private;
195
196 for (i = 0; i < sc->stripes; i++)
197 dm_put_device(ti, sc->stripe[i].dev);
198
199 flush_work(&sc->trigger_event);
200 kfree(sc);
201}
202
203static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
204 uint32_t *stripe, sector_t *result)
205{
206 sector_t chunk = dm_target_offset(sc->ti, sector);
207 sector_t chunk_offset;
208
209 if (sc->chunk_size_shift < 0)
210 chunk_offset = sector_div(chunk, sc->chunk_size);
211 else {
212 chunk_offset = chunk & (sc->chunk_size - 1);
213 chunk >>= sc->chunk_size_shift;
214 }
215
216 if (sc->stripes_shift < 0)
217 *stripe = sector_div(chunk, sc->stripes);
218 else {
219 *stripe = chunk & (sc->stripes - 1);
220 chunk >>= sc->stripes_shift;
221 }
222
223 if (sc->chunk_size_shift < 0)
224 chunk *= sc->chunk_size;
225 else
226 chunk <<= sc->chunk_size_shift;
227
228 *result = chunk + chunk_offset;
229}
230
231static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
232 uint32_t target_stripe, sector_t *result)
233{
234 uint32_t stripe;
235
236 stripe_map_sector(sc, sector, &stripe, result);
237 if (stripe == target_stripe)
238 return;
239
240 /* round down */
241 sector = *result;
242 if (sc->chunk_size_shift < 0)
243 *result -= sector_div(sector, sc->chunk_size);
244 else
245 *result = sector & ~(sector_t)(sc->chunk_size - 1);
246
247 if (target_stripe < stripe)
248 *result += sc->chunk_size; /* next chunk */
249}
250
251static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
252 uint32_t target_stripe)
253{
254 sector_t begin, end;
255
256 stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
257 target_stripe, &begin);
258 stripe_map_range_sector(sc, bio_end_sector(bio),
259 target_stripe, &end);
260 if (begin < end) {
261 bio_set_dev(bio, sc->stripe[target_stripe].dev->bdev);
262 bio->bi_iter.bi_sector = begin +
263 sc->stripe[target_stripe].physical_start;
264 bio->bi_iter.bi_size = to_bytes(end - begin);
265 return DM_MAPIO_REMAPPED;
266 } else {
267 /* The range doesn't map to the target stripe */
268 bio_endio(bio);
269 return DM_MAPIO_SUBMITTED;
270 }
271}
272
273static int stripe_map(struct dm_target *ti, struct bio *bio)
274{
275 struct stripe_c *sc = ti->private;
276 uint32_t stripe;
277 unsigned target_bio_nr;
278
279 if (bio->bi_opf & REQ_PREFLUSH) {
280 target_bio_nr = dm_bio_get_target_bio_nr(bio);
281 BUG_ON(target_bio_nr >= sc->stripes);
282 bio_set_dev(bio, sc->stripe[target_bio_nr].dev->bdev);
283 return DM_MAPIO_REMAPPED;
284 }
285 if (unlikely(bio_op(bio) == REQ_OP_DISCARD) ||
286 unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) ||
287 unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES) ||
288 unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) {
289 target_bio_nr = dm_bio_get_target_bio_nr(bio);
290 BUG_ON(target_bio_nr >= sc->stripes);
291 return stripe_map_range(sc, bio, target_bio_nr);
292 }
293
294 stripe_map_sector(sc, bio->bi_iter.bi_sector,
295 &stripe, &bio->bi_iter.bi_sector);
296
297 bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
298 bio_set_dev(bio, sc->stripe[stripe].dev->bdev);
299
300 return DM_MAPIO_REMAPPED;
301}
302
303#if IS_ENABLED(CONFIG_DAX_DRIVER)
304static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
305 long nr_pages, void **kaddr, pfn_t *pfn)
306{
307 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
308 struct stripe_c *sc = ti->private;
309 struct dax_device *dax_dev;
310 struct block_device *bdev;
311 uint32_t stripe;
312 long ret;
313
314 stripe_map_sector(sc, sector, &stripe, &dev_sector);
315 dev_sector += sc->stripe[stripe].physical_start;
316 dax_dev = sc->stripe[stripe].dev->dax_dev;
317 bdev = sc->stripe[stripe].dev->bdev;
318
319 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
320 if (ret)
321 return ret;
322 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
323}
324
325static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
326 void *addr, size_t bytes, struct iov_iter *i)
327{
328 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
329 struct stripe_c *sc = ti->private;
330 struct dax_device *dax_dev;
331 struct block_device *bdev;
332 uint32_t stripe;
333
334 stripe_map_sector(sc, sector, &stripe, &dev_sector);
335 dev_sector += sc->stripe[stripe].physical_start;
336 dax_dev = sc->stripe[stripe].dev->dax_dev;
337 bdev = sc->stripe[stripe].dev->bdev;
338
339 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
340 return 0;
341 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
342}
343
344static size_t stripe_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,
345 void *addr, size_t bytes, struct iov_iter *i)
346{
347 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
348 struct stripe_c *sc = ti->private;
349 struct dax_device *dax_dev;
350 struct block_device *bdev;
351 uint32_t stripe;
352
353 stripe_map_sector(sc, sector, &stripe, &dev_sector);
354 dev_sector += sc->stripe[stripe].physical_start;
355 dax_dev = sc->stripe[stripe].dev->dax_dev;
356 bdev = sc->stripe[stripe].dev->bdev;
357
358 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
359 return 0;
360 return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);
361}
362
363static int stripe_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
364 size_t nr_pages)
365{
366 int ret;
367 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
368 struct stripe_c *sc = ti->private;
369 struct dax_device *dax_dev;
370 struct block_device *bdev;
371 uint32_t stripe;
372
373 stripe_map_sector(sc, sector, &stripe, &dev_sector);
374 dev_sector += sc->stripe[stripe].physical_start;
375 dax_dev = sc->stripe[stripe].dev->dax_dev;
376 bdev = sc->stripe[stripe].dev->bdev;
377
378 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages << PAGE_SHIFT, &pgoff);
379 if (ret)
380 return ret;
381 return dax_zero_page_range(dax_dev, pgoff, nr_pages);
382}
383
384#else
385#define stripe_dax_direct_access NULL
386#define stripe_dax_copy_from_iter NULL
387#define stripe_dax_copy_to_iter NULL
388#define stripe_dax_zero_page_range NULL
389#endif
390
391/*
392 * Stripe status:
393 *
394 * INFO
395 * #stripes [stripe_name <stripe_name>] [group word count]
396 * [error count 'A|D' <error count 'A|D'>]
397 *
398 * TABLE
399 * #stripes [stripe chunk size]
400 * [stripe_name physical_start <stripe_name physical_start>]
401 *
402 */
403
404static void stripe_status(struct dm_target *ti, status_type_t type,
405 unsigned status_flags, char *result, unsigned maxlen)
406{
407 struct stripe_c *sc = (struct stripe_c *) ti->private;
408 unsigned int sz = 0;
409 unsigned int i;
410
411 switch (type) {
412 case STATUSTYPE_INFO:
413 DMEMIT("%d ", sc->stripes);
414 for (i = 0; i < sc->stripes; i++) {
415 DMEMIT("%s ", sc->stripe[i].dev->name);
416 }
417 DMEMIT("1 ");
418 for (i = 0; i < sc->stripes; i++) {
419 DMEMIT("%c", atomic_read(&(sc->stripe[i].error_count)) ?
420 'D' : 'A');
421 }
422 break;
423
424 case STATUSTYPE_TABLE:
425 DMEMIT("%d %llu", sc->stripes,
426 (unsigned long long)sc->chunk_size);
427 for (i = 0; i < sc->stripes; i++)
428 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
429 (unsigned long long)sc->stripe[i].physical_start);
430 break;
431 }
432}
433
434static int stripe_end_io(struct dm_target *ti, struct bio *bio,
435 blk_status_t *error)
436{
437 unsigned i;
438 char major_minor[16];
439 struct stripe_c *sc = ti->private;
440
441 if (!*error)
442 return DM_ENDIO_DONE; /* I/O complete */
443
444 if (bio->bi_opf & REQ_RAHEAD)
445 return DM_ENDIO_DONE;
446
447 if (*error == BLK_STS_NOTSUPP)
448 return DM_ENDIO_DONE;
449
450 memset(major_minor, 0, sizeof(major_minor));
451 sprintf(major_minor, "%d:%d", MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)));
452
453 /*
454 * Test to see which stripe drive triggered the event
455 * and increment error count for all stripes on that device.
456 * If the error count for a given device exceeds the threshold
457 * value we will no longer trigger any further events.
458 */
459 for (i = 0; i < sc->stripes; i++)
460 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
461 atomic_inc(&(sc->stripe[i].error_count));
462 if (atomic_read(&(sc->stripe[i].error_count)) <
463 DM_IO_ERROR_THRESHOLD)
464 schedule_work(&sc->trigger_event);
465 }
466
467 return DM_ENDIO_DONE;
468}
469
470static int stripe_iterate_devices(struct dm_target *ti,
471 iterate_devices_callout_fn fn, void *data)
472{
473 struct stripe_c *sc = ti->private;
474 int ret = 0;
475 unsigned i = 0;
476
477 do {
478 ret = fn(ti, sc->stripe[i].dev,
479 sc->stripe[i].physical_start,
480 sc->stripe_width, data);
481 } while (!ret && ++i < sc->stripes);
482
483 return ret;
484}
485
486static void stripe_io_hints(struct dm_target *ti,
487 struct queue_limits *limits)
488{
489 struct stripe_c *sc = ti->private;
490 unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
491
492 blk_limits_io_min(limits, chunk_size);
493 blk_limits_io_opt(limits, chunk_size * sc->stripes);
494}
495
496static struct target_type stripe_target = {
497 .name = "striped",
498 .version = {1, 6, 0},
499 .features = DM_TARGET_PASSES_INTEGRITY,
500 .module = THIS_MODULE,
501 .ctr = stripe_ctr,
502 .dtr = stripe_dtr,
503 .map = stripe_map,
504 .end_io = stripe_end_io,
505 .status = stripe_status,
506 .iterate_devices = stripe_iterate_devices,
507 .io_hints = stripe_io_hints,
508 .direct_access = stripe_dax_direct_access,
509 .dax_copy_from_iter = stripe_dax_copy_from_iter,
510 .dax_copy_to_iter = stripe_dax_copy_to_iter,
511 .dax_zero_page_range = stripe_dax_zero_page_range,
512};
513
514int __init dm_stripe_init(void)
515{
516 int r;
517
518 r = dm_register_target(&stripe_target);
519 if (r < 0)
520 DMWARN("target registration failed");
521
522 return r;
523}
524
525void dm_stripe_exit(void)
526{
527 dm_unregister_target(&stripe_target);
528}
1/*
2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm.h"
8#include <linux/device-mapper.h>
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#include <linux/log2.h>
16
17#define DM_MSG_PREFIX "striped"
18#define DM_IO_ERROR_THRESHOLD 15
19
20struct stripe {
21 struct dm_dev *dev;
22 sector_t physical_start;
23
24 atomic_t error_count;
25};
26
27struct stripe_c {
28 uint32_t stripes;
29 int stripes_shift;
30
31 /* The size of this target / num. stripes */
32 sector_t stripe_width;
33
34 uint32_t chunk_size;
35 int chunk_size_shift;
36
37 /* Needed for handling events */
38 struct dm_target *ti;
39
40 /* Work struct used for triggering events*/
41 struct work_struct trigger_event;
42
43 struct stripe stripe[0];
44};
45
46/*
47 * An event is triggered whenever a drive
48 * drops out of a stripe volume.
49 */
50static void trigger_event(struct work_struct *work)
51{
52 struct stripe_c *sc = container_of(work, struct stripe_c,
53 trigger_event);
54 dm_table_event(sc->ti->table);
55}
56
57static inline struct stripe_c *alloc_context(unsigned int stripes)
58{
59 size_t len;
60
61 if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
62 stripes))
63 return NULL;
64
65 len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
66
67 return kmalloc(len, GFP_KERNEL);
68}
69
70/*
71 * Parse a single <dev> <sector> pair
72 */
73static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
74 unsigned int stripe, char **argv)
75{
76 unsigned long long start;
77 char dummy;
78
79 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
80 return -EINVAL;
81
82 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
83 &sc->stripe[stripe].dev))
84 return -ENXIO;
85
86 sc->stripe[stripe].physical_start = start;
87
88 return 0;
89}
90
91/*
92 * Construct a striped mapping.
93 * <number of stripes> <chunk size> [<dev_path> <offset>]+
94 */
95static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
96{
97 struct stripe_c *sc;
98 sector_t width, tmp_len;
99 uint32_t stripes;
100 uint32_t chunk_size;
101 int r;
102 unsigned int i;
103
104 if (argc < 2) {
105 ti->error = "Not enough arguments";
106 return -EINVAL;
107 }
108
109 if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
110 ti->error = "Invalid stripe count";
111 return -EINVAL;
112 }
113
114 if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
115 ti->error = "Invalid chunk_size";
116 return -EINVAL;
117 }
118
119 width = ti->len;
120 if (sector_div(width, stripes)) {
121 ti->error = "Target length not divisible by "
122 "number of stripes";
123 return -EINVAL;
124 }
125
126 tmp_len = width;
127 if (sector_div(tmp_len, chunk_size)) {
128 ti->error = "Target length not divisible by "
129 "chunk size";
130 return -EINVAL;
131 }
132
133 /*
134 * Do we have enough arguments for that many stripes ?
135 */
136 if (argc != (2 + 2 * stripes)) {
137 ti->error = "Not enough destinations "
138 "specified";
139 return -EINVAL;
140 }
141
142 sc = alloc_context(stripes);
143 if (!sc) {
144 ti->error = "Memory allocation for striped context "
145 "failed";
146 return -ENOMEM;
147 }
148
149 INIT_WORK(&sc->trigger_event, trigger_event);
150
151 /* Set pointer to dm target; used in trigger_event */
152 sc->ti = ti;
153 sc->stripes = stripes;
154 sc->stripe_width = width;
155
156 if (stripes & (stripes - 1))
157 sc->stripes_shift = -1;
158 else
159 sc->stripes_shift = __ffs(stripes);
160
161 r = dm_set_target_max_io_len(ti, chunk_size);
162 if (r)
163 return r;
164
165 ti->num_flush_bios = stripes;
166 ti->num_discard_bios = stripes;
167 ti->num_write_same_bios = stripes;
168
169 sc->chunk_size = chunk_size;
170 if (chunk_size & (chunk_size - 1))
171 sc->chunk_size_shift = -1;
172 else
173 sc->chunk_size_shift = __ffs(chunk_size);
174
175 /*
176 * Get the stripe destinations.
177 */
178 for (i = 0; i < stripes; i++) {
179 argv += 2;
180
181 r = get_stripe(ti, sc, i, argv);
182 if (r < 0) {
183 ti->error = "Couldn't parse stripe destination";
184 while (i--)
185 dm_put_device(ti, sc->stripe[i].dev);
186 kfree(sc);
187 return r;
188 }
189 atomic_set(&(sc->stripe[i].error_count), 0);
190 }
191
192 ti->private = sc;
193
194 return 0;
195}
196
197static void stripe_dtr(struct dm_target *ti)
198{
199 unsigned int i;
200 struct stripe_c *sc = (struct stripe_c *) ti->private;
201
202 for (i = 0; i < sc->stripes; i++)
203 dm_put_device(ti, sc->stripe[i].dev);
204
205 flush_work(&sc->trigger_event);
206 kfree(sc);
207}
208
209static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
210 uint32_t *stripe, sector_t *result)
211{
212 sector_t chunk = dm_target_offset(sc->ti, sector);
213 sector_t chunk_offset;
214
215 if (sc->chunk_size_shift < 0)
216 chunk_offset = sector_div(chunk, sc->chunk_size);
217 else {
218 chunk_offset = chunk & (sc->chunk_size - 1);
219 chunk >>= sc->chunk_size_shift;
220 }
221
222 if (sc->stripes_shift < 0)
223 *stripe = sector_div(chunk, sc->stripes);
224 else {
225 *stripe = chunk & (sc->stripes - 1);
226 chunk >>= sc->stripes_shift;
227 }
228
229 if (sc->chunk_size_shift < 0)
230 chunk *= sc->chunk_size;
231 else
232 chunk <<= sc->chunk_size_shift;
233
234 *result = chunk + chunk_offset;
235}
236
237static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
238 uint32_t target_stripe, sector_t *result)
239{
240 uint32_t stripe;
241
242 stripe_map_sector(sc, sector, &stripe, result);
243 if (stripe == target_stripe)
244 return;
245
246 /* round down */
247 sector = *result;
248 if (sc->chunk_size_shift < 0)
249 *result -= sector_div(sector, sc->chunk_size);
250 else
251 *result = sector & ~(sector_t)(sc->chunk_size - 1);
252
253 if (target_stripe < stripe)
254 *result += sc->chunk_size; /* next chunk */
255}
256
257static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
258 uint32_t target_stripe)
259{
260 sector_t begin, end;
261
262 stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
263 target_stripe, &begin);
264 stripe_map_range_sector(sc, bio_end_sector(bio),
265 target_stripe, &end);
266 if (begin < end) {
267 bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
268 bio->bi_iter.bi_sector = begin +
269 sc->stripe[target_stripe].physical_start;
270 bio->bi_iter.bi_size = to_bytes(end - begin);
271 return DM_MAPIO_REMAPPED;
272 } else {
273 /* The range doesn't map to the target stripe */
274 bio_endio(bio, 0);
275 return DM_MAPIO_SUBMITTED;
276 }
277}
278
279static int stripe_map(struct dm_target *ti, struct bio *bio)
280{
281 struct stripe_c *sc = ti->private;
282 uint32_t stripe;
283 unsigned target_bio_nr;
284
285 if (bio->bi_rw & REQ_FLUSH) {
286 target_bio_nr = dm_bio_get_target_bio_nr(bio);
287 BUG_ON(target_bio_nr >= sc->stripes);
288 bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
289 return DM_MAPIO_REMAPPED;
290 }
291 if (unlikely(bio->bi_rw & REQ_DISCARD) ||
292 unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
293 target_bio_nr = dm_bio_get_target_bio_nr(bio);
294 BUG_ON(target_bio_nr >= sc->stripes);
295 return stripe_map_range(sc, bio, target_bio_nr);
296 }
297
298 stripe_map_sector(sc, bio->bi_iter.bi_sector,
299 &stripe, &bio->bi_iter.bi_sector);
300
301 bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
302 bio->bi_bdev = sc->stripe[stripe].dev->bdev;
303
304 return DM_MAPIO_REMAPPED;
305}
306
307/*
308 * Stripe status:
309 *
310 * INFO
311 * #stripes [stripe_name <stripe_name>] [group word count]
312 * [error count 'A|D' <error count 'A|D'>]
313 *
314 * TABLE
315 * #stripes [stripe chunk size]
316 * [stripe_name physical_start <stripe_name physical_start>]
317 *
318 */
319
320static void stripe_status(struct dm_target *ti, status_type_t type,
321 unsigned status_flags, char *result, unsigned maxlen)
322{
323 struct stripe_c *sc = (struct stripe_c *) ti->private;
324 char buffer[sc->stripes + 1];
325 unsigned int sz = 0;
326 unsigned int i;
327
328 switch (type) {
329 case STATUSTYPE_INFO:
330 DMEMIT("%d ", sc->stripes);
331 for (i = 0; i < sc->stripes; i++) {
332 DMEMIT("%s ", sc->stripe[i].dev->name);
333 buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
334 'D' : 'A';
335 }
336 buffer[i] = '\0';
337 DMEMIT("1 %s", buffer);
338 break;
339
340 case STATUSTYPE_TABLE:
341 DMEMIT("%d %llu", sc->stripes,
342 (unsigned long long)sc->chunk_size);
343 for (i = 0; i < sc->stripes; i++)
344 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
345 (unsigned long long)sc->stripe[i].physical_start);
346 break;
347 }
348}
349
350static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
351{
352 unsigned i;
353 char major_minor[16];
354 struct stripe_c *sc = ti->private;
355
356 if (!error)
357 return 0; /* I/O complete */
358
359 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
360 return error;
361
362 if (error == -EOPNOTSUPP)
363 return error;
364
365 memset(major_minor, 0, sizeof(major_minor));
366 sprintf(major_minor, "%d:%d",
367 MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
368 MINOR(disk_devt(bio->bi_bdev->bd_disk)));
369
370 /*
371 * Test to see which stripe drive triggered the event
372 * and increment error count for all stripes on that device.
373 * If the error count for a given device exceeds the threshold
374 * value we will no longer trigger any further events.
375 */
376 for (i = 0; i < sc->stripes; i++)
377 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
378 atomic_inc(&(sc->stripe[i].error_count));
379 if (atomic_read(&(sc->stripe[i].error_count)) <
380 DM_IO_ERROR_THRESHOLD)
381 schedule_work(&sc->trigger_event);
382 }
383
384 return error;
385}
386
387static int stripe_iterate_devices(struct dm_target *ti,
388 iterate_devices_callout_fn fn, void *data)
389{
390 struct stripe_c *sc = ti->private;
391 int ret = 0;
392 unsigned i = 0;
393
394 do {
395 ret = fn(ti, sc->stripe[i].dev,
396 sc->stripe[i].physical_start,
397 sc->stripe_width, data);
398 } while (!ret && ++i < sc->stripes);
399
400 return ret;
401}
402
403static void stripe_io_hints(struct dm_target *ti,
404 struct queue_limits *limits)
405{
406 struct stripe_c *sc = ti->private;
407 unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
408
409 blk_limits_io_min(limits, chunk_size);
410 blk_limits_io_opt(limits, chunk_size * sc->stripes);
411}
412
413static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
414 struct bio_vec *biovec, int max_size)
415{
416 struct stripe_c *sc = ti->private;
417 sector_t bvm_sector = bvm->bi_sector;
418 uint32_t stripe;
419 struct request_queue *q;
420
421 stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
422
423 q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
424 if (!q->merge_bvec_fn)
425 return max_size;
426
427 bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
428 bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
429
430 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
431}
432
433static struct target_type stripe_target = {
434 .name = "striped",
435 .version = {1, 5, 1},
436 .module = THIS_MODULE,
437 .ctr = stripe_ctr,
438 .dtr = stripe_dtr,
439 .map = stripe_map,
440 .end_io = stripe_end_io,
441 .status = stripe_status,
442 .iterate_devices = stripe_iterate_devices,
443 .io_hints = stripe_io_hints,
444 .merge = stripe_merge,
445};
446
447int __init dm_stripe_init(void)
448{
449 int r;
450
451 r = dm_register_target(&stripe_target);
452 if (r < 0) {
453 DMWARN("target registration failed");
454 return r;
455 }
456
457 return r;
458}
459
460void dm_stripe_exit(void)
461{
462 dm_unregister_target(&stripe_target);
463}