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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/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}
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}