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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 <linux/device-mapper.h>
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>
14#include <linux/log2.h>
15
16#define DM_MSG_PREFIX "striped"
17#define DM_IO_ERROR_THRESHOLD 15
18
19struct stripe {
20 struct dm_dev *dev;
21 sector_t physical_start;
22
23 atomic_t error_count;
24};
25
26struct stripe_c {
27 uint32_t stripes;
28 int stripes_shift;
29 sector_t stripes_mask;
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
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[0];
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
58static inline struct stripe_c *alloc_context(unsigned int stripes)
59{
60 size_t len;
61
62 if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
63 stripes))
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 */
74static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
75 unsigned int stripe, char **argv)
76{
77 unsigned long long start;
78
79 if (sscanf(argv[1], "%llu", &start) != 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 (2^^n)> [<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;
99 uint32_t stripes;
100 uint32_t chunk_size;
101 char *end;
102 int r;
103 unsigned int i;
104
105 if (argc < 2) {
106 ti->error = "Not enough arguments";
107 return -EINVAL;
108 }
109
110 stripes = simple_strtoul(argv[0], &end, 10);
111 if (!stripes || *end) {
112 ti->error = "Invalid stripe count";
113 return -EINVAL;
114 }
115
116 chunk_size = simple_strtoul(argv[1], &end, 10);
117 if (*end) {
118 ti->error = "Invalid chunk_size";
119 return -EINVAL;
120 }
121
122 /*
123 * chunk_size is a power of two
124 */
125 if (!is_power_of_2(chunk_size) ||
126 (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
127 ti->error = "Invalid chunk size";
128 return -EINVAL;
129 }
130
131 if (ti->len & (chunk_size - 1)) {
132 ti->error = "Target length not divisible by "
133 "chunk size";
134 return -EINVAL;
135 }
136
137 width = ti->len;
138 if (sector_div(width, stripes)) {
139 ti->error = "Target length not divisible by "
140 "number of stripes";
141 return -EINVAL;
142 }
143
144 /*
145 * Do we have enough arguments for that many stripes ?
146 */
147 if (argc != (2 + 2 * stripes)) {
148 ti->error = "Not enough destinations "
149 "specified";
150 return -EINVAL;
151 }
152
153 sc = alloc_context(stripes);
154 if (!sc) {
155 ti->error = "Memory allocation for striped context "
156 "failed";
157 return -ENOMEM;
158 }
159
160 INIT_WORK(&sc->trigger_event, trigger_event);
161
162 /* Set pointer to dm target; used in trigger_event */
163 sc->ti = ti;
164 sc->stripes = stripes;
165 sc->stripe_width = width;
166
167 if (stripes & (stripes - 1))
168 sc->stripes_shift = -1;
169 else {
170 sc->stripes_shift = ffs(stripes) - 1;
171 sc->stripes_mask = ((sector_t) stripes) - 1;
172 }
173
174 ti->split_io = chunk_size;
175 ti->num_flush_requests = stripes;
176 ti->num_discard_requests = stripes;
177
178 sc->chunk_shift = ffs(chunk_size) - 1;
179 sc->chunk_mask = ((sector_t) chunk_size) - 1;
180
181 /*
182 * Get the stripe destinations.
183 */
184 for (i = 0; i < stripes; i++) {
185 argv += 2;
186
187 r = get_stripe(ti, sc, i, argv);
188 if (r < 0) {
189 ti->error = "Couldn't parse stripe destination";
190 while (i--)
191 dm_put_device(ti, sc->stripe[i].dev);
192 kfree(sc);
193 return r;
194 }
195 atomic_set(&(sc->stripe[i].error_count), 0);
196 }
197
198 ti->private = sc;
199
200 return 0;
201}
202
203static void stripe_dtr(struct dm_target *ti)
204{
205 unsigned int i;
206 struct stripe_c *sc = (struct stripe_c *) ti->private;
207
208 for (i = 0; i < sc->stripes; i++)
209 dm_put_device(ti, sc->stripe[i].dev);
210
211 flush_work_sync(&sc->trigger_event);
212 kfree(sc);
213}
214
215static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
216 uint32_t *stripe, sector_t *result)
217{
218 sector_t offset = dm_target_offset(sc->ti, sector);
219 sector_t chunk = offset >> sc->chunk_shift;
220
221 if (sc->stripes_shift < 0)
222 *stripe = sector_div(chunk, sc->stripes);
223 else {
224 *stripe = chunk & sc->stripes_mask;
225 chunk >>= sc->stripes_shift;
226 }
227
228 *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask);
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 *result &= ~sc->chunk_mask; /* round down */
240 if (target_stripe < stripe)
241 *result += sc->chunk_mask + 1; /* next chunk */
242}
243
244static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
245 uint32_t target_stripe)
246{
247 sector_t begin, end;
248
249 stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
250 stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
251 target_stripe, &end);
252 if (begin < end) {
253 bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
254 bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
255 bio->bi_size = to_bytes(end - begin);
256 return DM_MAPIO_REMAPPED;
257 } else {
258 /* The range doesn't map to the target stripe */
259 bio_endio(bio, 0);
260 return DM_MAPIO_SUBMITTED;
261 }
262}
263
264static int stripe_map(struct dm_target *ti, struct bio *bio,
265 union map_info *map_context)
266{
267 struct stripe_c *sc = ti->private;
268 uint32_t stripe;
269 unsigned target_request_nr;
270
271 if (bio->bi_rw & REQ_FLUSH) {
272 target_request_nr = map_context->target_request_nr;
273 BUG_ON(target_request_nr >= sc->stripes);
274 bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
275 return DM_MAPIO_REMAPPED;
276 }
277 if (unlikely(bio->bi_rw & REQ_DISCARD)) {
278 target_request_nr = map_context->target_request_nr;
279 BUG_ON(target_request_nr >= sc->stripes);
280 return stripe_map_discard(sc, bio, target_request_nr);
281 }
282
283 stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
284
285 bio->bi_sector += sc->stripe[stripe].physical_start;
286 bio->bi_bdev = sc->stripe[stripe].dev->bdev;
287
288 return DM_MAPIO_REMAPPED;
289}
290
291/*
292 * Stripe status:
293 *
294 * INFO
295 * #stripes [stripe_name <stripe_name>] [group word count]
296 * [error count 'A|D' <error count 'A|D'>]
297 *
298 * TABLE
299 * #stripes [stripe chunk size]
300 * [stripe_name physical_start <stripe_name physical_start>]
301 *
302 */
303
304static int stripe_status(struct dm_target *ti,
305 status_type_t type, char *result, unsigned int maxlen)
306{
307 struct stripe_c *sc = (struct stripe_c *) ti->private;
308 char buffer[sc->stripes + 1];
309 unsigned int sz = 0;
310 unsigned int i;
311
312 switch (type) {
313 case STATUSTYPE_INFO:
314 DMEMIT("%d ", sc->stripes);
315 for (i = 0; i < sc->stripes; i++) {
316 DMEMIT("%s ", sc->stripe[i].dev->name);
317 buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
318 'D' : 'A';
319 }
320 buffer[i] = '\0';
321 DMEMIT("1 %s", buffer);
322 break;
323
324 case STATUSTYPE_TABLE:
325 DMEMIT("%d %llu", sc->stripes,
326 (unsigned long long)sc->chunk_mask + 1);
327 for (i = 0; i < sc->stripes; i++)
328 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
329 (unsigned long long)sc->stripe[i].physical_start);
330 break;
331 }
332 return 0;
333}
334
335static int stripe_end_io(struct dm_target *ti, struct bio *bio,
336 int error, union map_info *map_context)
337{
338 unsigned i;
339 char major_minor[16];
340 struct stripe_c *sc = ti->private;
341
342 if (!error)
343 return 0; /* I/O complete */
344
345 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
346 return error;
347
348 if (error == -EOPNOTSUPP)
349 return error;
350
351 memset(major_minor, 0, sizeof(major_minor));
352 sprintf(major_minor, "%d:%d",
353 MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
354 MINOR(disk_devt(bio->bi_bdev->bd_disk)));
355
356 /*
357 * Test to see which stripe drive triggered the event
358 * and increment error count for all stripes on that device.
359 * If the error count for a given device exceeds the threshold
360 * value we will no longer trigger any further events.
361 */
362 for (i = 0; i < sc->stripes; i++)
363 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
364 atomic_inc(&(sc->stripe[i].error_count));
365 if (atomic_read(&(sc->stripe[i].error_count)) <
366 DM_IO_ERROR_THRESHOLD)
367 schedule_work(&sc->trigger_event);
368 }
369
370 return error;
371}
372
373static int stripe_iterate_devices(struct dm_target *ti,
374 iterate_devices_callout_fn fn, void *data)
375{
376 struct stripe_c *sc = ti->private;
377 int ret = 0;
378 unsigned i = 0;
379
380 do {
381 ret = fn(ti, sc->stripe[i].dev,
382 sc->stripe[i].physical_start,
383 sc->stripe_width, data);
384 } while (!ret && ++i < sc->stripes);
385
386 return ret;
387}
388
389static void stripe_io_hints(struct dm_target *ti,
390 struct queue_limits *limits)
391{
392 struct stripe_c *sc = ti->private;
393 unsigned chunk_size = (sc->chunk_mask + 1) << 9;
394
395 blk_limits_io_min(limits, chunk_size);
396 blk_limits_io_opt(limits, chunk_size * sc->stripes);
397}
398
399static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
400 struct bio_vec *biovec, int max_size)
401{
402 struct stripe_c *sc = ti->private;
403 sector_t bvm_sector = bvm->bi_sector;
404 uint32_t stripe;
405 struct request_queue *q;
406
407 stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
408
409 q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
410 if (!q->merge_bvec_fn)
411 return max_size;
412
413 bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
414 bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
415
416 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
417}
418
419static struct target_type stripe_target = {
420 .name = "striped",
421 .version = {1, 4, 0},
422 .module = THIS_MODULE,
423 .ctr = stripe_ctr,
424 .dtr = stripe_dtr,
425 .map = stripe_map,
426 .end_io = stripe_end_io,
427 .status = stripe_status,
428 .iterate_devices = stripe_iterate_devices,
429 .io_hints = stripe_io_hints,
430 .merge = stripe_merge,
431};
432
433int __init dm_stripe_init(void)
434{
435 int r;
436
437 r = dm_register_target(&stripe_target);
438 if (r < 0) {
439 DMWARN("target registration failed");
440 return r;
441 }
442
443 return r;
444}
445
446void dm_stripe_exit(void)
447{
448 dm_unregister_target(&stripe_target);
449}