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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 <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 char dummy;
79
80 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
81 return -EINVAL;
82
83 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
84 &sc->stripe[stripe].dev))
85 return -ENXIO;
86
87 sc->stripe[stripe].physical_start = start;
88
89 return 0;
90}
91
92/*
93 * Construct a striped mapping.
94 * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
95 */
96static 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) {
107 ti->error = "Not enough arguments";
108 return -EINVAL;
109 }
110
111 stripes = simple_strtoul(argv[0], &end, 10);
112 if (!stripes || *end) {
113 ti->error = "Invalid stripe count";
114 return -EINVAL;
115 }
116
117 chunk_size = simple_strtoul(argv[1], &end, 10);
118 if (*end) {
119 ti->error = "Invalid chunk_size";
120 return -EINVAL;
121 }
122
123 /*
124 * chunk_size is a power of two
125 */
126 if (!is_power_of_2(chunk_size) ||
127 (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
128 ti->error = "Invalid chunk size";
129 return -EINVAL;
130 }
131
132 if (ti->len & (chunk_size - 1)) {
133 ti->error = "Target length not divisible by "
134 "chunk size";
135 return -EINVAL;
136 }
137
138 width = ti->len;
139 if (sector_div(width, stripes)) {
140 ti->error = "Target length not divisible by "
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)) {
149 ti->error = "Not enough destinations "
150 "specified";
151 return -EINVAL;
152 }
153
154 sc = alloc_context(stripes);
155 if (!sc) {
156 ti->error = "Memory allocation for striped context "
157 "failed";
158 return -ENOMEM;
159 }
160
161 INIT_WORK(&sc->trigger_event, trigger_event);
162
163 /* Set pointer to dm target; used in trigger_event */
164 sc->ti = ti;
165 sc->stripes = stripes;
166 sc->stripe_width = width;
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
175 ti->split_io = chunk_size;
176 ti->num_flush_requests = stripes;
177 ti->num_discard_requests = stripes;
178
179 sc->chunk_shift = ffs(chunk_size) - 1;
180 sc->chunk_mask = ((sector_t) chunk_size) - 1;
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) {
190 ti->error = "Couldn't parse stripe destination";
191 while (i--)
192 dm_put_device(ti, sc->stripe[i].dev);
193 kfree(sc);
194 return r;
195 }
196 atomic_set(&(sc->stripe[i].error_count), 0);
197 }
198
199 ti->private = sc;
200
201 return 0;
202}
203
204static 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
212 flush_work_sync(&sc->trigger_event);
213 kfree(sc);
214}
215
216static 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
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
229 *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask);
230}
231
232static 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
245static 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
265static int stripe_map(struct dm_target *ti, struct bio *bio,
266 union map_info *map_context)
267{
268 struct stripe_c *sc = ti->private;
269 uint32_t stripe;
270 unsigned target_request_nr;
271
272 if (bio->bi_rw & REQ_FLUSH) {
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;
276 return DM_MAPIO_REMAPPED;
277 }
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 }
283
284 stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
285
286 bio->bi_sector += sc->stripe[stripe].physical_start;
287 bio->bi_bdev = sc->stripe[stripe].dev->bdev;
288
289 return DM_MAPIO_REMAPPED;
290}
291
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
305static 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;
309 char buffer[sc->stripes + 1];
310 unsigned int sz = 0;
311 unsigned int i;
312
313 switch (type) {
314 case STATUSTYPE_INFO:
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);
323 break;
324
325 case STATUSTYPE_TABLE:
326 DMEMIT("%d %llu", sc->stripes,
327 (unsigned long long)sc->chunk_mask + 1);
328 for (i = 0; i < sc->stripes; i++)
329 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
330 (unsigned long long)sc->stripe[i].physical_start);
331 break;
332 }
333 return 0;
334}
335
336static 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
346 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
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",
354 MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
355 MINOR(disk_devt(bio->bi_bdev->bd_disk)));
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)
368 schedule_work(&sc->trigger_event);
369 }
370
371 return error;
372}
373
374static 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
381 do {
382 ret = fn(ti, sc->stripe[i].dev,
383 sc->stripe[i].physical_start,
384 sc->stripe_width, data);
385 } while (!ret && ++i < sc->stripes);
386
387 return ret;
388}
389
390static 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);
397 blk_limits_io_opt(limits, chunk_size * sc->stripes);
398}
399
400static 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
420static struct target_type stripe_target = {
421 .name = "striped",
422 .version = {1, 4, 0},
423 .module = THIS_MODULE,
424 .ctr = stripe_ctr,
425 .dtr = stripe_dtr,
426 .map = stripe_map,
427 .end_io = stripe_end_io,
428 .status = stripe_status,
429 .iterate_devices = stripe_iterate_devices,
430 .io_hints = stripe_io_hints,
431 .merge = stripe_merge,
432};
433
434int __init dm_stripe_init(void)
435{
436 int r;
437
438 r = dm_register_target(&stripe_target);
439 if (r < 0) {
440 DMWARN("target registration failed");
441 return r;
442 }
443
444 return r;
445}
446
447void dm_stripe_exit(void)
448{
449 dm_unregister_target(&stripe_target);
450}
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}