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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9#include <linux/device-mapper.h>
10
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/blkdev.h>
14#include <linux/bio.h>
15#include <linux/dax.h>
16#include <linux/slab.h>
17#include <linux/log2.h>
18
19static struct workqueue_struct *dm_stripe_wq;
20
21#define DM_MSG_PREFIX "striped"
22#define DM_IO_ERROR_THRESHOLD 15
23
24struct stripe {
25 struct dm_dev *dev;
26 sector_t physical_start;
27
28 atomic_t error_count;
29};
30
31struct stripe_c {
32 uint32_t stripes;
33 int stripes_shift;
34
35 /* The size of this target / num. stripes */
36 sector_t stripe_width;
37
38 uint32_t chunk_size;
39 int chunk_size_shift;
40
41 /* Needed for handling events */
42 struct dm_target *ti;
43
44 /* Work struct used for triggering events*/
45 struct work_struct trigger_event;
46
47 struct stripe stripe[] __counted_by(stripes);
48};
49
50/*
51 * An event is triggered whenever a drive
52 * drops out of a stripe volume.
53 */
54static void trigger_event(struct work_struct *work)
55{
56 struct stripe_c *sc = container_of(work, struct stripe_c,
57 trigger_event);
58 dm_table_event(sc->ti->table);
59}
60
61/*
62 * Parse a single <dev> <sector> pair
63 */
64static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
65 unsigned int stripe, char **argv)
66{
67 unsigned long long start;
68 char dummy;
69 int ret;
70
71 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
72 return -EINVAL;
73
74 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
75 &sc->stripe[stripe].dev);
76 if (ret)
77 return ret;
78
79 sc->stripe[stripe].physical_start = start;
80
81 return 0;
82}
83
84/*
85 * Construct a striped mapping.
86 * <number of stripes> <chunk size> [<dev_path> <offset>]+
87 */
88static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
89{
90 struct stripe_c *sc;
91 sector_t width, tmp_len;
92 uint32_t stripes;
93 uint32_t chunk_size;
94 int r;
95 unsigned int i;
96
97 if (argc < 2) {
98 ti->error = "Not enough arguments";
99 return -EINVAL;
100 }
101
102 if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
103 ti->error = "Invalid stripe count";
104 return -EINVAL;
105 }
106
107 if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
108 ti->error = "Invalid chunk_size";
109 return -EINVAL;
110 }
111
112 width = ti->len;
113 if (sector_div(width, stripes)) {
114 ti->error = "Target length not divisible by number of stripes";
115 return -EINVAL;
116 }
117
118 tmp_len = width;
119 if (sector_div(tmp_len, chunk_size)) {
120 ti->error = "Target length not divisible by chunk size";
121 return -EINVAL;
122 }
123
124 /*
125 * Do we have enough arguments for that many stripes ?
126 */
127 if (argc != (2 + 2 * stripes)) {
128 ti->error = "Not enough destinations 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 failed";
135 return -ENOMEM;
136 }
137
138 INIT_WORK(&sc->trigger_event, trigger_event);
139
140 /* Set pointer to dm target; used in trigger_event */
141 sc->ti = ti;
142 sc->stripes = stripes;
143 sc->stripe_width = width;
144
145 if (stripes & (stripes - 1))
146 sc->stripes_shift = -1;
147 else
148 sc->stripes_shift = __ffs(stripes);
149
150 r = dm_set_target_max_io_len(ti, chunk_size);
151 if (r) {
152 kfree(sc);
153 return r;
154 }
155
156 ti->num_flush_bios = stripes;
157 ti->num_discard_bios = stripes;
158 ti->num_secure_erase_bios = stripes;
159 ti->num_write_zeroes_bios = stripes;
160
161 sc->chunk_size = chunk_size;
162 if (chunk_size & (chunk_size - 1))
163 sc->chunk_size_shift = -1;
164 else
165 sc->chunk_size_shift = __ffs(chunk_size);
166
167 /*
168 * Get the stripe destinations.
169 */
170 for (i = 0; i < stripes; i++) {
171 argv += 2;
172
173 r = get_stripe(ti, sc, i, argv);
174 if (r < 0) {
175 ti->error = "Couldn't parse stripe destination";
176 while (i--)
177 dm_put_device(ti, sc->stripe[i].dev);
178 kfree(sc);
179 return r;
180 }
181 atomic_set(&(sc->stripe[i].error_count), 0);
182 }
183
184 ti->private = sc;
185
186 return 0;
187}
188
189static void stripe_dtr(struct dm_target *ti)
190{
191 unsigned int i;
192 struct stripe_c *sc = ti->private;
193
194 for (i = 0; i < sc->stripes; i++)
195 dm_put_device(ti, sc->stripe[i].dev);
196
197 flush_work(&sc->trigger_event);
198 kfree(sc);
199}
200
201static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
202 uint32_t *stripe, sector_t *result)
203{
204 sector_t chunk = dm_target_offset(sc->ti, sector);
205 sector_t chunk_offset;
206
207 if (sc->chunk_size_shift < 0)
208 chunk_offset = sector_div(chunk, sc->chunk_size);
209 else {
210 chunk_offset = chunk & (sc->chunk_size - 1);
211 chunk >>= sc->chunk_size_shift;
212 }
213
214 if (sc->stripes_shift < 0)
215 *stripe = sector_div(chunk, sc->stripes);
216 else {
217 *stripe = chunk & (sc->stripes - 1);
218 chunk >>= sc->stripes_shift;
219 }
220
221 if (sc->chunk_size_shift < 0)
222 chunk *= sc->chunk_size;
223 else
224 chunk <<= sc->chunk_size_shift;
225
226 *result = chunk + chunk_offset;
227}
228
229static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
230 uint32_t target_stripe, sector_t *result)
231{
232 uint32_t stripe;
233
234 stripe_map_sector(sc, sector, &stripe, result);
235 if (stripe == target_stripe)
236 return;
237
238 /* round down */
239 sector = *result;
240 if (sc->chunk_size_shift < 0)
241 *result -= sector_div(sector, sc->chunk_size);
242 else
243 *result = sector & ~(sector_t)(sc->chunk_size - 1);
244
245 if (target_stripe < stripe)
246 *result += sc->chunk_size; /* next chunk */
247}
248
249static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
250 uint32_t target_stripe)
251{
252 sector_t begin, end;
253
254 stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
255 target_stripe, &begin);
256 stripe_map_range_sector(sc, bio_end_sector(bio),
257 target_stripe, &end);
258 if (begin < end) {
259 bio_set_dev(bio, sc->stripe[target_stripe].dev->bdev);
260 bio->bi_iter.bi_sector = begin +
261 sc->stripe[target_stripe].physical_start;
262 bio->bi_iter.bi_size = to_bytes(end - begin);
263 return DM_MAPIO_REMAPPED;
264 }
265
266 /* The range doesn't map to the target stripe */
267 bio_endio(bio);
268 return DM_MAPIO_SUBMITTED;
269}
270
271int stripe_map(struct dm_target *ti, struct bio *bio)
272{
273 struct stripe_c *sc = ti->private;
274 uint32_t stripe;
275 unsigned int target_bio_nr;
276
277 if (bio->bi_opf & REQ_PREFLUSH) {
278 target_bio_nr = dm_bio_get_target_bio_nr(bio);
279 BUG_ON(target_bio_nr >= sc->stripes);
280 bio_set_dev(bio, sc->stripe[target_bio_nr].dev->bdev);
281 return DM_MAPIO_REMAPPED;
282 }
283 if (unlikely(bio_op(bio) == REQ_OP_DISCARD) ||
284 unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) ||
285 unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES)) {
286 target_bio_nr = dm_bio_get_target_bio_nr(bio);
287 BUG_ON(target_bio_nr >= sc->stripes);
288 return stripe_map_range(sc, bio, target_bio_nr);
289 }
290
291 stripe_map_sector(sc, bio->bi_iter.bi_sector,
292 &stripe, &bio->bi_iter.bi_sector);
293
294 bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
295 bio_set_dev(bio, sc->stripe[stripe].dev->bdev);
296
297 return DM_MAPIO_REMAPPED;
298}
299
300#if IS_ENABLED(CONFIG_FS_DAX)
301static struct dax_device *stripe_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
302{
303 struct stripe_c *sc = ti->private;
304 struct block_device *bdev;
305 sector_t dev_sector;
306 uint32_t stripe;
307
308 stripe_map_sector(sc, *pgoff * PAGE_SECTORS, &stripe, &dev_sector);
309 dev_sector += sc->stripe[stripe].physical_start;
310 bdev = sc->stripe[stripe].dev->bdev;
311
312 *pgoff = (get_start_sect(bdev) + dev_sector) >> PAGE_SECTORS_SHIFT;
313 return sc->stripe[stripe].dev->dax_dev;
314}
315
316static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
317 long nr_pages, enum dax_access_mode mode, void **kaddr,
318 pfn_t *pfn)
319{
320 struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
321
322 return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
323}
324
325static int stripe_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
326 size_t nr_pages)
327{
328 struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
329
330 return dax_zero_page_range(dax_dev, pgoff, nr_pages);
331}
332
333static size_t stripe_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff,
334 void *addr, size_t bytes, struct iov_iter *i)
335{
336 struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
337
338 return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);
339}
340
341#else
342#define stripe_dax_direct_access NULL
343#define stripe_dax_zero_page_range NULL
344#define stripe_dax_recovery_write NULL
345#endif
346
347/*
348 * Stripe status:
349 *
350 * INFO
351 * #stripes [stripe_name <stripe_name>] [group word count]
352 * [error count 'A|D' <error count 'A|D'>]
353 *
354 * TABLE
355 * #stripes [stripe chunk size]
356 * [stripe_name physical_start <stripe_name physical_start>]
357 *
358 */
359
360static void stripe_status(struct dm_target *ti, status_type_t type,
361 unsigned int status_flags, char *result, unsigned int maxlen)
362{
363 struct stripe_c *sc = ti->private;
364 unsigned int sz = 0;
365 unsigned int i;
366
367 switch (type) {
368 case STATUSTYPE_INFO:
369 DMEMIT("%d ", sc->stripes);
370 for (i = 0; i < sc->stripes; i++)
371 DMEMIT("%s ", sc->stripe[i].dev->name);
372
373 DMEMIT("1 ");
374 for (i = 0; i < sc->stripes; i++)
375 DMEMIT("%c", atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
376 break;
377
378 case STATUSTYPE_TABLE:
379 DMEMIT("%d %llu", sc->stripes,
380 (unsigned long long)sc->chunk_size);
381 for (i = 0; i < sc->stripes; i++)
382 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
383 (unsigned long long)sc->stripe[i].physical_start);
384 break;
385
386 case STATUSTYPE_IMA:
387 DMEMIT_TARGET_NAME_VERSION(ti->type);
388 DMEMIT(",stripes=%d,chunk_size=%llu", sc->stripes,
389 (unsigned long long)sc->chunk_size);
390
391 for (i = 0; i < sc->stripes; i++) {
392 DMEMIT(",stripe_%d_device_name=%s", i, sc->stripe[i].dev->name);
393 DMEMIT(",stripe_%d_physical_start=%llu", i,
394 (unsigned long long)sc->stripe[i].physical_start);
395 DMEMIT(",stripe_%d_status=%c", i,
396 atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
397 }
398 DMEMIT(";");
399 break;
400 }
401}
402
403static int stripe_end_io(struct dm_target *ti, struct bio *bio,
404 blk_status_t *error)
405{
406 unsigned int i;
407 char major_minor[16];
408 struct stripe_c *sc = ti->private;
409
410 if (!*error)
411 return DM_ENDIO_DONE; /* I/O complete */
412
413 if (bio->bi_opf & REQ_RAHEAD)
414 return DM_ENDIO_DONE;
415
416 if (*error == BLK_STS_NOTSUPP)
417 return DM_ENDIO_DONE;
418
419 memset(major_minor, 0, sizeof(major_minor));
420 sprintf(major_minor, "%d:%d", MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)));
421
422 /*
423 * Test to see which stripe drive triggered the event
424 * and increment error count for all stripes on that device.
425 * If the error count for a given device exceeds the threshold
426 * value we will no longer trigger any further events.
427 */
428 for (i = 0; i < sc->stripes; i++)
429 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
430 atomic_inc(&(sc->stripe[i].error_count));
431 if (atomic_read(&(sc->stripe[i].error_count)) <
432 DM_IO_ERROR_THRESHOLD)
433 queue_work(dm_stripe_wq, &sc->trigger_event);
434 }
435
436 return DM_ENDIO_DONE;
437}
438
439static int stripe_iterate_devices(struct dm_target *ti,
440 iterate_devices_callout_fn fn, void *data)
441{
442 struct stripe_c *sc = ti->private;
443 int ret = 0;
444 unsigned int i = 0;
445
446 do {
447 ret = fn(ti, sc->stripe[i].dev,
448 sc->stripe[i].physical_start,
449 sc->stripe_width, data);
450 } while (!ret && ++i < sc->stripes);
451
452 return ret;
453}
454
455static void stripe_io_hints(struct dm_target *ti,
456 struct queue_limits *limits)
457{
458 struct stripe_c *sc = ti->private;
459 unsigned int chunk_size = sc->chunk_size << SECTOR_SHIFT;
460
461 blk_limits_io_min(limits, chunk_size);
462 blk_limits_io_opt(limits, chunk_size * sc->stripes);
463}
464
465static struct target_type stripe_target = {
466 .name = "striped",
467 .version = {1, 6, 0},
468 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT,
469 .module = THIS_MODULE,
470 .ctr = stripe_ctr,
471 .dtr = stripe_dtr,
472 .map = stripe_map,
473 .end_io = stripe_end_io,
474 .status = stripe_status,
475 .iterate_devices = stripe_iterate_devices,
476 .io_hints = stripe_io_hints,
477 .direct_access = stripe_dax_direct_access,
478 .dax_zero_page_range = stripe_dax_zero_page_range,
479 .dax_recovery_write = stripe_dax_recovery_write,
480};
481
482int __init dm_stripe_init(void)
483{
484 int r;
485
486 dm_stripe_wq = alloc_workqueue("dm_stripe_wq", 0, 0);
487 if (!dm_stripe_wq)
488 return -ENOMEM;
489 r = dm_register_target(&stripe_target);
490 if (r < 0) {
491 destroy_workqueue(dm_stripe_wq);
492 DMWARN("target registration failed");
493 }
494
495 return r;
496}
497
498void dm_stripe_exit(void)
499{
500 dm_unregister_target(&stripe_target);
501 destroy_workqueue(dm_stripe_wq);
502}
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 int ret;
79
80 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
81 return -EINVAL;
82
83 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
84 &sc->stripe[stripe].dev);
85 if (ret)
86 return ret;
87
88 sc->stripe[stripe].physical_start = start;
89
90 return 0;
91}
92
93/*
94 * Construct a striped mapping.
95 * <number of stripes> <chunk size> [<dev_path> <offset>]+
96 */
97static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
98{
99 struct stripe_c *sc;
100 sector_t width, tmp_len;
101 uint32_t stripes;
102 uint32_t chunk_size;
103 int r;
104 unsigned int i;
105
106 if (argc < 2) {
107 ti->error = "Not enough arguments";
108 return -EINVAL;
109 }
110
111 if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
112 ti->error = "Invalid stripe count";
113 return -EINVAL;
114 }
115
116 if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
117 ti->error = "Invalid chunk_size";
118 return -EINVAL;
119 }
120
121 width = ti->len;
122 if (sector_div(width, stripes)) {
123 ti->error = "Target length not divisible by "
124 "number of stripes";
125 return -EINVAL;
126 }
127
128 tmp_len = width;
129 if (sector_div(tmp_len, chunk_size)) {
130 ti->error = "Target length not divisible by "
131 "chunk size";
132 return -EINVAL;
133 }
134
135 /*
136 * Do we have enough arguments for that many stripes ?
137 */
138 if (argc != (2 + 2 * stripes)) {
139 ti->error = "Not enough destinations "
140 "specified";
141 return -EINVAL;
142 }
143
144 sc = alloc_context(stripes);
145 if (!sc) {
146 ti->error = "Memory allocation for striped context "
147 "failed";
148 return -ENOMEM;
149 }
150
151 INIT_WORK(&sc->trigger_event, trigger_event);
152
153 /* Set pointer to dm target; used in trigger_event */
154 sc->ti = ti;
155 sc->stripes = stripes;
156 sc->stripe_width = width;
157
158 if (stripes & (stripes - 1))
159 sc->stripes_shift = -1;
160 else
161 sc->stripes_shift = __ffs(stripes);
162
163 r = dm_set_target_max_io_len(ti, chunk_size);
164 if (r) {
165 kfree(sc);
166 return r;
167 }
168
169 ti->num_flush_bios = stripes;
170 ti->num_discard_bios = stripes;
171 ti->num_write_same_bios = stripes;
172
173 sc->chunk_size = chunk_size;
174 if (chunk_size & (chunk_size - 1))
175 sc->chunk_size_shift = -1;
176 else
177 sc->chunk_size_shift = __ffs(chunk_size);
178
179 /*
180 * Get the stripe destinations.
181 */
182 for (i = 0; i < stripes; i++) {
183 argv += 2;
184
185 r = get_stripe(ti, sc, i, argv);
186 if (r < 0) {
187 ti->error = "Couldn't parse stripe destination";
188 while (i--)
189 dm_put_device(ti, sc->stripe[i].dev);
190 kfree(sc);
191 return r;
192 }
193 atomic_set(&(sc->stripe[i].error_count), 0);
194 }
195
196 ti->private = sc;
197
198 return 0;
199}
200
201static void stripe_dtr(struct dm_target *ti)
202{
203 unsigned int i;
204 struct stripe_c *sc = (struct stripe_c *) ti->private;
205
206 for (i = 0; i < sc->stripes; i++)
207 dm_put_device(ti, sc->stripe[i].dev);
208
209 flush_work(&sc->trigger_event);
210 kfree(sc);
211}
212
213static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
214 uint32_t *stripe, sector_t *result)
215{
216 sector_t chunk = dm_target_offset(sc->ti, sector);
217 sector_t chunk_offset;
218
219 if (sc->chunk_size_shift < 0)
220 chunk_offset = sector_div(chunk, sc->chunk_size);
221 else {
222 chunk_offset = chunk & (sc->chunk_size - 1);
223 chunk >>= sc->chunk_size_shift;
224 }
225
226 if (sc->stripes_shift < 0)
227 *stripe = sector_div(chunk, sc->stripes);
228 else {
229 *stripe = chunk & (sc->stripes - 1);
230 chunk >>= sc->stripes_shift;
231 }
232
233 if (sc->chunk_size_shift < 0)
234 chunk *= sc->chunk_size;
235 else
236 chunk <<= sc->chunk_size_shift;
237
238 *result = chunk + chunk_offset;
239}
240
241static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
242 uint32_t target_stripe, sector_t *result)
243{
244 uint32_t stripe;
245
246 stripe_map_sector(sc, sector, &stripe, result);
247 if (stripe == target_stripe)
248 return;
249
250 /* round down */
251 sector = *result;
252 if (sc->chunk_size_shift < 0)
253 *result -= sector_div(sector, sc->chunk_size);
254 else
255 *result = sector & ~(sector_t)(sc->chunk_size - 1);
256
257 if (target_stripe < stripe)
258 *result += sc->chunk_size; /* next chunk */
259}
260
261static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
262 uint32_t target_stripe)
263{
264 sector_t begin, end;
265
266 stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
267 target_stripe, &begin);
268 stripe_map_range_sector(sc, bio_end_sector(bio),
269 target_stripe, &end);
270 if (begin < end) {
271 bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
272 bio->bi_iter.bi_sector = begin +
273 sc->stripe[target_stripe].physical_start;
274 bio->bi_iter.bi_size = to_bytes(end - begin);
275 return DM_MAPIO_REMAPPED;
276 } else {
277 /* The range doesn't map to the target stripe */
278 bio_endio(bio);
279 return DM_MAPIO_SUBMITTED;
280 }
281}
282
283static int stripe_map(struct dm_target *ti, struct bio *bio)
284{
285 struct stripe_c *sc = ti->private;
286 uint32_t stripe;
287 unsigned target_bio_nr;
288
289 if (bio->bi_rw & REQ_FLUSH) {
290 target_bio_nr = dm_bio_get_target_bio_nr(bio);
291 BUG_ON(target_bio_nr >= sc->stripes);
292 bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
293 return DM_MAPIO_REMAPPED;
294 }
295 if (unlikely(bio->bi_rw & REQ_DISCARD) ||
296 unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
297 target_bio_nr = dm_bio_get_target_bio_nr(bio);
298 BUG_ON(target_bio_nr >= sc->stripes);
299 return stripe_map_range(sc, bio, target_bio_nr);
300 }
301
302 stripe_map_sector(sc, bio->bi_iter.bi_sector,
303 &stripe, &bio->bi_iter.bi_sector);
304
305 bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
306 bio->bi_bdev = sc->stripe[stripe].dev->bdev;
307
308 return DM_MAPIO_REMAPPED;
309}
310
311/*
312 * Stripe status:
313 *
314 * INFO
315 * #stripes [stripe_name <stripe_name>] [group word count]
316 * [error count 'A|D' <error count 'A|D'>]
317 *
318 * TABLE
319 * #stripes [stripe chunk size]
320 * [stripe_name physical_start <stripe_name physical_start>]
321 *
322 */
323
324static void stripe_status(struct dm_target *ti, status_type_t type,
325 unsigned status_flags, char *result, unsigned maxlen)
326{
327 struct stripe_c *sc = (struct stripe_c *) ti->private;
328 char buffer[sc->stripes + 1];
329 unsigned int sz = 0;
330 unsigned int i;
331
332 switch (type) {
333 case STATUSTYPE_INFO:
334 DMEMIT("%d ", sc->stripes);
335 for (i = 0; i < sc->stripes; i++) {
336 DMEMIT("%s ", sc->stripe[i].dev->name);
337 buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
338 'D' : 'A';
339 }
340 buffer[i] = '\0';
341 DMEMIT("1 %s", buffer);
342 break;
343
344 case STATUSTYPE_TABLE:
345 DMEMIT("%d %llu", sc->stripes,
346 (unsigned long long)sc->chunk_size);
347 for (i = 0; i < sc->stripes; i++)
348 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
349 (unsigned long long)sc->stripe[i].physical_start);
350 break;
351 }
352}
353
354static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
355{
356 unsigned i;
357 char major_minor[16];
358 struct stripe_c *sc = ti->private;
359
360 if (!error)
361 return 0; /* I/O complete */
362
363 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
364 return error;
365
366 if (error == -EOPNOTSUPP)
367 return error;
368
369 memset(major_minor, 0, sizeof(major_minor));
370 sprintf(major_minor, "%d:%d",
371 MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
372 MINOR(disk_devt(bio->bi_bdev->bd_disk)));
373
374 /*
375 * Test to see which stripe drive triggered the event
376 * and increment error count for all stripes on that device.
377 * If the error count for a given device exceeds the threshold
378 * value we will no longer trigger any further events.
379 */
380 for (i = 0; i < sc->stripes; i++)
381 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
382 atomic_inc(&(sc->stripe[i].error_count));
383 if (atomic_read(&(sc->stripe[i].error_count)) <
384 DM_IO_ERROR_THRESHOLD)
385 schedule_work(&sc->trigger_event);
386 }
387
388 return error;
389}
390
391static int stripe_iterate_devices(struct dm_target *ti,
392 iterate_devices_callout_fn fn, void *data)
393{
394 struct stripe_c *sc = ti->private;
395 int ret = 0;
396 unsigned i = 0;
397
398 do {
399 ret = fn(ti, sc->stripe[i].dev,
400 sc->stripe[i].physical_start,
401 sc->stripe_width, data);
402 } while (!ret && ++i < sc->stripes);
403
404 return ret;
405}
406
407static void stripe_io_hints(struct dm_target *ti,
408 struct queue_limits *limits)
409{
410 struct stripe_c *sc = ti->private;
411 unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
412
413 blk_limits_io_min(limits, chunk_size);
414 blk_limits_io_opt(limits, chunk_size * sc->stripes);
415}
416
417static struct target_type stripe_target = {
418 .name = "striped",
419 .version = {1, 5, 1},
420 .module = THIS_MODULE,
421 .ctr = stripe_ctr,
422 .dtr = stripe_dtr,
423 .map = stripe_map,
424 .end_io = stripe_end_io,
425 .status = stripe_status,
426 .iterate_devices = stripe_iterate_devices,
427 .io_hints = stripe_io_hints,
428};
429
430int __init dm_stripe_init(void)
431{
432 int r;
433
434 r = dm_register_target(&stripe_target);
435 if (r < 0)
436 DMWARN("target registration failed");
437
438 return r;
439}
440
441void dm_stripe_exit(void)
442{
443 dm_unregister_target(&stripe_target);
444}