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1da177e4 LT |
1 | /* |
2 | raid0.c : Multiple Devices driver for Linux | |
3 | Copyright (C) 1994-96 Marc ZYNGIER | |
4 | <zyngier@ufr-info-p7.ibp.fr> or | |
5 | <maz@gloups.fdn.fr> | |
6 | Copyright (C) 1999, 2000 Ingo Molnar, Red Hat | |
7 | ||
8 | ||
9 | RAID-0 management functions. | |
10 | ||
11 | This program is free software; you can redistribute it and/or modify | |
12 | it under the terms of the GNU General Public License as published by | |
13 | the Free Software Foundation; either version 2, or (at your option) | |
14 | any later version. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | (for example /usr/src/linux/COPYING); if not, write to the Free | |
18 | Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/raid/raid0.h> | |
23 | ||
24 | #define MAJOR_NR MD_MAJOR | |
25 | #define MD_DRIVER | |
26 | #define MD_PERSONALITY | |
27 | ||
165125e1 | 28 | static void raid0_unplug(struct request_queue *q) |
1da177e4 LT |
29 | { |
30 | mddev_t *mddev = q->queuedata; | |
31 | raid0_conf_t *conf = mddev_to_conf(mddev); | |
32 | mdk_rdev_t **devlist = conf->strip_zone[0].dev; | |
33 | int i; | |
34 | ||
35 | for (i=0; i<mddev->raid_disks; i++) { | |
165125e1 | 36 | struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev); |
1da177e4 LT |
37 | |
38 | if (r_queue->unplug_fn) | |
39 | r_queue->unplug_fn(r_queue); | |
40 | } | |
41 | } | |
42 | ||
26be34dc N |
43 | static int raid0_congested(void *data, int bits) |
44 | { | |
45 | mddev_t *mddev = data; | |
46 | raid0_conf_t *conf = mddev_to_conf(mddev); | |
47 | mdk_rdev_t **devlist = conf->strip_zone[0].dev; | |
48 | int i, ret = 0; | |
49 | ||
50 | for (i = 0; i < mddev->raid_disks && !ret ; i++) { | |
165125e1 | 51 | struct request_queue *q = bdev_get_queue(devlist[i]->bdev); |
26be34dc N |
52 | |
53 | ret |= bdi_congested(&q->backing_dev_info, bits); | |
54 | } | |
55 | return ret; | |
56 | } | |
57 | ||
1da177e4 LT |
58 | |
59 | static int create_strip_zones (mddev_t *mddev) | |
60 | { | |
61 | int i, c, j; | |
62 | sector_t current_offset, curr_zone_offset; | |
63 | sector_t min_spacing; | |
64 | raid0_conf_t *conf = mddev_to_conf(mddev); | |
65 | mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev; | |
66 | struct list_head *tmp1, *tmp2; | |
67 | struct strip_zone *zone; | |
68 | int cnt; | |
69 | char b[BDEVNAME_SIZE]; | |
70 | ||
71 | /* | |
72 | * The number of 'same size groups' | |
73 | */ | |
74 | conf->nr_strip_zones = 0; | |
75 | ||
76 | ITERATE_RDEV(mddev,rdev1,tmp1) { | |
77 | printk("raid0: looking at %s\n", | |
78 | bdevname(rdev1->bdev,b)); | |
79 | c = 0; | |
80 | ITERATE_RDEV(mddev,rdev2,tmp2) { | |
81 | printk("raid0: comparing %s(%llu)", | |
82 | bdevname(rdev1->bdev,b), | |
83 | (unsigned long long)rdev1->size); | |
84 | printk(" with %s(%llu)\n", | |
85 | bdevname(rdev2->bdev,b), | |
86 | (unsigned long long)rdev2->size); | |
87 | if (rdev2 == rdev1) { | |
88 | printk("raid0: END\n"); | |
89 | break; | |
90 | } | |
91 | if (rdev2->size == rdev1->size) | |
92 | { | |
93 | /* | |
94 | * Not unique, don't count it as a new | |
95 | * group | |
96 | */ | |
97 | printk("raid0: EQUAL\n"); | |
98 | c = 1; | |
99 | break; | |
100 | } | |
101 | printk("raid0: NOT EQUAL\n"); | |
102 | } | |
103 | if (!c) { | |
104 | printk("raid0: ==> UNIQUE\n"); | |
105 | conf->nr_strip_zones++; | |
106 | printk("raid0: %d zones\n", conf->nr_strip_zones); | |
107 | } | |
108 | } | |
109 | printk("raid0: FINAL %d zones\n", conf->nr_strip_zones); | |
110 | ||
9ffae0cf | 111 | conf->strip_zone = kzalloc(sizeof(struct strip_zone)* |
1da177e4 LT |
112 | conf->nr_strip_zones, GFP_KERNEL); |
113 | if (!conf->strip_zone) | |
114 | return 1; | |
9ffae0cf | 115 | conf->devlist = kzalloc(sizeof(mdk_rdev_t*)* |
1da177e4 LT |
116 | conf->nr_strip_zones*mddev->raid_disks, |
117 | GFP_KERNEL); | |
118 | if (!conf->devlist) | |
119 | return 1; | |
120 | ||
1da177e4 LT |
121 | /* The first zone must contain all devices, so here we check that |
122 | * there is a proper alignment of slots to devices and find them all | |
123 | */ | |
124 | zone = &conf->strip_zone[0]; | |
125 | cnt = 0; | |
126 | smallest = NULL; | |
127 | zone->dev = conf->devlist; | |
128 | ITERATE_RDEV(mddev, rdev1, tmp1) { | |
129 | int j = rdev1->raid_disk; | |
130 | ||
131 | if (j < 0 || j >= mddev->raid_disks) { | |
132 | printk("raid0: bad disk number %d - aborting!\n", j); | |
133 | goto abort; | |
134 | } | |
135 | if (zone->dev[j]) { | |
136 | printk("raid0: multiple devices for %d - aborting!\n", | |
137 | j); | |
138 | goto abort; | |
139 | } | |
140 | zone->dev[j] = rdev1; | |
141 | ||
142 | blk_queue_stack_limits(mddev->queue, | |
143 | rdev1->bdev->bd_disk->queue); | |
144 | /* as we don't honour merge_bvec_fn, we must never risk | |
145 | * violating it, so limit ->max_sector to one PAGE, as | |
146 | * a one page request is never in violation. | |
147 | */ | |
148 | ||
149 | if (rdev1->bdev->bd_disk->queue->merge_bvec_fn && | |
150 | mddev->queue->max_sectors > (PAGE_SIZE>>9)) | |
151 | blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
152 | ||
153 | if (!smallest || (rdev1->size <smallest->size)) | |
154 | smallest = rdev1; | |
155 | cnt++; | |
156 | } | |
157 | if (cnt != mddev->raid_disks) { | |
158 | printk("raid0: too few disks (%d of %d) - aborting!\n", | |
159 | cnt, mddev->raid_disks); | |
160 | goto abort; | |
161 | } | |
162 | zone->nb_dev = cnt; | |
163 | zone->size = smallest->size * cnt; | |
164 | zone->zone_offset = 0; | |
165 | ||
166 | current_offset = smallest->size; | |
167 | curr_zone_offset = zone->size; | |
168 | ||
169 | /* now do the other zones */ | |
170 | for (i = 1; i < conf->nr_strip_zones; i++) | |
171 | { | |
172 | zone = conf->strip_zone + i; | |
173 | zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks; | |
174 | ||
175 | printk("raid0: zone %d\n", i); | |
176 | zone->dev_offset = current_offset; | |
177 | smallest = NULL; | |
178 | c = 0; | |
179 | ||
180 | for (j=0; j<cnt; j++) { | |
181 | char b[BDEVNAME_SIZE]; | |
182 | rdev = conf->strip_zone[0].dev[j]; | |
183 | printk("raid0: checking %s ...", bdevname(rdev->bdev,b)); | |
184 | if (rdev->size > current_offset) | |
185 | { | |
186 | printk(" contained as device %d\n", c); | |
187 | zone->dev[c] = rdev; | |
188 | c++; | |
189 | if (!smallest || (rdev->size <smallest->size)) { | |
190 | smallest = rdev; | |
191 | printk(" (%llu) is smallest!.\n", | |
192 | (unsigned long long)rdev->size); | |
193 | } | |
194 | } else | |
195 | printk(" nope.\n"); | |
196 | } | |
197 | ||
198 | zone->nb_dev = c; | |
199 | zone->size = (smallest->size - current_offset) * c; | |
200 | printk("raid0: zone->nb_dev: %d, size: %llu\n", | |
201 | zone->nb_dev, (unsigned long long)zone->size); | |
202 | ||
203 | zone->zone_offset = curr_zone_offset; | |
204 | curr_zone_offset += zone->size; | |
205 | ||
206 | current_offset = smallest->size; | |
207 | printk("raid0: current zone offset: %llu\n", | |
208 | (unsigned long long)current_offset); | |
209 | } | |
210 | ||
211 | /* Now find appropriate hash spacing. | |
212 | * We want a number which causes most hash entries to cover | |
213 | * at most two strips, but the hash table must be at most | |
214 | * 1 PAGE. We choose the smallest strip, or contiguous collection | |
215 | * of strips, that has big enough size. We never consider the last | |
216 | * strip though as it's size has no bearing on the efficacy of the hash | |
217 | * table. | |
218 | */ | |
219 | conf->hash_spacing = curr_zone_offset; | |
220 | min_spacing = curr_zone_offset; | |
221 | sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*)); | |
222 | for (i=0; i < conf->nr_strip_zones-1; i++) { | |
223 | sector_t sz = 0; | |
224 | for (j=i; j<conf->nr_strip_zones-1 && | |
225 | sz < min_spacing ; j++) | |
226 | sz += conf->strip_zone[j].size; | |
227 | if (sz >= min_spacing && sz < conf->hash_spacing) | |
228 | conf->hash_spacing = sz; | |
229 | } | |
230 | ||
231 | mddev->queue->unplug_fn = raid0_unplug; | |
232 | ||
26be34dc N |
233 | mddev->queue->backing_dev_info.congested_fn = raid0_congested; |
234 | mddev->queue->backing_dev_info.congested_data = mddev; | |
1da177e4 LT |
235 | |
236 | printk("raid0: done.\n"); | |
237 | return 0; | |
238 | abort: | |
239 | return 1; | |
240 | } | |
241 | ||
242 | /** | |
243 | * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged | |
244 | * @q: request queue | |
245 | * @bio: the buffer head that's been built up so far | |
246 | * @biovec: the request that could be merged to it. | |
247 | * | |
248 | * Return amount of bytes we can accept at this offset | |
249 | */ | |
165125e1 | 250 | static int raid0_mergeable_bvec(struct request_queue *q, struct bio *bio, struct bio_vec *biovec) |
1da177e4 LT |
251 | { |
252 | mddev_t *mddev = q->queuedata; | |
253 | sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); | |
254 | int max; | |
255 | unsigned int chunk_sectors = mddev->chunk_size >> 9; | |
256 | unsigned int bio_sectors = bio->bi_size >> 9; | |
257 | ||
258 | max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; | |
259 | if (max < 0) max = 0; /* bio_add cannot handle a negative return */ | |
260 | if (max <= biovec->bv_len && bio_sectors == 0) | |
261 | return biovec->bv_len; | |
262 | else | |
263 | return max; | |
264 | } | |
265 | ||
266 | static int raid0_run (mddev_t *mddev) | |
267 | { | |
268 | unsigned cur=0, i=0, nb_zone; | |
269 | s64 size; | |
270 | raid0_conf_t *conf; | |
271 | mdk_rdev_t *rdev; | |
272 | struct list_head *tmp; | |
273 | ||
2604b703 N |
274 | if (mddev->chunk_size == 0) { |
275 | printk(KERN_ERR "md/raid0: non-zero chunk size required.\n"); | |
276 | return -EINVAL; | |
277 | } | |
278 | printk(KERN_INFO "%s: setting max_sectors to %d, segment boundary to %d\n", | |
1da177e4 LT |
279 | mdname(mddev), |
280 | mddev->chunk_size >> 9, | |
281 | (mddev->chunk_size>>1)-1); | |
282 | blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9); | |
283 | blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1); | |
284 | ||
285 | conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL); | |
286 | if (!conf) | |
287 | goto out; | |
288 | mddev->private = (void *)conf; | |
289 | ||
290 | conf->strip_zone = NULL; | |
291 | conf->devlist = NULL; | |
292 | if (create_strip_zones (mddev)) | |
293 | goto out_free_conf; | |
294 | ||
295 | /* calculate array device size */ | |
296 | mddev->array_size = 0; | |
297 | ITERATE_RDEV(mddev,rdev,tmp) | |
298 | mddev->array_size += rdev->size; | |
299 | ||
300 | printk("raid0 : md_size is %llu blocks.\n", | |
301 | (unsigned long long)mddev->array_size); | |
302 | printk("raid0 : conf->hash_spacing is %llu blocks.\n", | |
303 | (unsigned long long)conf->hash_spacing); | |
304 | { | |
1da177e4 LT |
305 | sector_t s = mddev->array_size; |
306 | sector_t space = conf->hash_spacing; | |
307 | int round; | |
308 | conf->preshift = 0; | |
1eb29128 | 309 | if (sizeof(sector_t) > sizeof(u32)) { |
1da177e4 | 310 | /*shift down space and s so that sector_div will work */ |
1eb29128 | 311 | while (space > (sector_t) (~(u32)0)) { |
1da177e4 LT |
312 | s >>= 1; |
313 | space >>= 1; | |
314 | s += 1; /* force round-up */ | |
315 | conf->preshift++; | |
316 | } | |
317 | } | |
1eb29128 | 318 | round = sector_div(s, (u32)space) ? 1 : 0; |
1da177e4 LT |
319 | nb_zone = s + round; |
320 | } | |
321 | printk("raid0 : nb_zone is %d.\n", nb_zone); | |
322 | ||
323 | printk("raid0 : Allocating %Zd bytes for hash.\n", | |
324 | nb_zone*sizeof(struct strip_zone*)); | |
325 | conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL); | |
326 | if (!conf->hash_table) | |
327 | goto out_free_conf; | |
328 | size = conf->strip_zone[cur].size; | |
329 | ||
5c4c3331 N |
330 | conf->hash_table[0] = conf->strip_zone + cur; |
331 | for (i=1; i< nb_zone; i++) { | |
1da177e4 LT |
332 | while (size <= conf->hash_spacing) { |
333 | cur++; | |
334 | size += conf->strip_zone[cur].size; | |
335 | } | |
336 | size -= conf->hash_spacing; | |
5c4c3331 | 337 | conf->hash_table[i] = conf->strip_zone + cur; |
1da177e4 LT |
338 | } |
339 | if (conf->preshift) { | |
340 | conf->hash_spacing >>= conf->preshift; | |
341 | /* round hash_spacing up so when we divide by it, we | |
342 | * err on the side of too-low, which is safest | |
343 | */ | |
344 | conf->hash_spacing++; | |
345 | } | |
346 | ||
347 | /* calculate the max read-ahead size. | |
348 | * For read-ahead of large files to be effective, we need to | |
349 | * readahead at least twice a whole stripe. i.e. number of devices | |
350 | * multiplied by chunk size times 2. | |
351 | * If an individual device has an ra_pages greater than the | |
352 | * chunk size, then we will not drive that device as hard as it | |
353 | * wants. We consider this a configuration error: a larger | |
354 | * chunksize should be used in that case. | |
355 | */ | |
356 | { | |
2d1f3b5d | 357 | int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_SIZE; |
1da177e4 LT |
358 | if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) |
359 | mddev->queue->backing_dev_info.ra_pages = 2* stripe; | |
360 | } | |
361 | ||
362 | ||
363 | blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec); | |
364 | return 0; | |
365 | ||
366 | out_free_conf: | |
990a8baf JJ |
367 | kfree(conf->strip_zone); |
368 | kfree(conf->devlist); | |
1da177e4 LT |
369 | kfree(conf); |
370 | mddev->private = NULL; | |
371 | out: | |
29fc7e3e | 372 | return -ENOMEM; |
1da177e4 LT |
373 | } |
374 | ||
375 | static int raid0_stop (mddev_t *mddev) | |
376 | { | |
377 | raid0_conf_t *conf = mddev_to_conf(mddev); | |
378 | ||
379 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ | |
990a8baf | 380 | kfree(conf->hash_table); |
1da177e4 | 381 | conf->hash_table = NULL; |
990a8baf | 382 | kfree(conf->strip_zone); |
1da177e4 | 383 | conf->strip_zone = NULL; |
990a8baf | 384 | kfree(conf); |
1da177e4 LT |
385 | mddev->private = NULL; |
386 | ||
387 | return 0; | |
388 | } | |
389 | ||
165125e1 | 390 | static int raid0_make_request (struct request_queue *q, struct bio *bio) |
1da177e4 LT |
391 | { |
392 | mddev_t *mddev = q->queuedata; | |
393 | unsigned int sect_in_chunk, chunksize_bits, chunk_size, chunk_sects; | |
394 | raid0_conf_t *conf = mddev_to_conf(mddev); | |
395 | struct strip_zone *zone; | |
396 | mdk_rdev_t *tmp_dev; | |
787f17fe | 397 | sector_t chunk; |
1da177e4 | 398 | sector_t block, rsect; |
a362357b | 399 | const int rw = bio_data_dir(bio); |
1da177e4 | 400 | |
e5dcdd80 | 401 | if (unlikely(bio_barrier(bio))) { |
6712ecf8 | 402 | bio_endio(bio, -EOPNOTSUPP); |
e5dcdd80 N |
403 | return 0; |
404 | } | |
405 | ||
a362357b JA |
406 | disk_stat_inc(mddev->gendisk, ios[rw]); |
407 | disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); | |
1da177e4 LT |
408 | |
409 | chunk_size = mddev->chunk_size >> 10; | |
410 | chunk_sects = mddev->chunk_size >> 9; | |
411 | chunksize_bits = ffz(~chunk_size); | |
412 | block = bio->bi_sector >> 1; | |
413 | ||
414 | ||
415 | if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) { | |
416 | struct bio_pair *bp; | |
417 | /* Sanity check -- queue functions should prevent this happening */ | |
418 | if (bio->bi_vcnt != 1 || | |
419 | bio->bi_idx != 0) | |
420 | goto bad_map; | |
421 | /* This is a one page bio that upper layers | |
422 | * refuse to split for us, so we need to split it. | |
423 | */ | |
424 | bp = bio_split(bio, bio_split_pool, chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); | |
425 | if (raid0_make_request(q, &bp->bio1)) | |
426 | generic_make_request(&bp->bio1); | |
427 | if (raid0_make_request(q, &bp->bio2)) | |
428 | generic_make_request(&bp->bio2); | |
429 | ||
430 | bio_pair_release(bp); | |
431 | return 0; | |
432 | } | |
433 | ||
434 | ||
435 | { | |
1da177e4 | 436 | sector_t x = block >> conf->preshift; |
1eb29128 | 437 | sector_div(x, (u32)conf->hash_spacing); |
1da177e4 LT |
438 | zone = conf->hash_table[x]; |
439 | } | |
440 | ||
441 | while (block >= (zone->zone_offset + zone->size)) | |
442 | zone++; | |
443 | ||
444 | sect_in_chunk = bio->bi_sector & ((chunk_size<<1) -1); | |
445 | ||
446 | ||
447 | { | |
448 | sector_t x = (block - zone->zone_offset) >> chunksize_bits; | |
449 | ||
450 | sector_div(x, zone->nb_dev); | |
451 | chunk = x; | |
1da177e4 LT |
452 | |
453 | x = block >> chunksize_bits; | |
454 | tmp_dev = zone->dev[sector_div(x, zone->nb_dev)]; | |
455 | } | |
456 | rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1) | |
457 | + sect_in_chunk; | |
458 | ||
459 | bio->bi_bdev = tmp_dev->bdev; | |
460 | bio->bi_sector = rsect + tmp_dev->data_offset; | |
461 | ||
462 | /* | |
463 | * Let the main block layer submit the IO and resolve recursion: | |
464 | */ | |
465 | return 1; | |
466 | ||
467 | bad_map: | |
468 | printk("raid0_make_request bug: can't convert block across chunks" | |
469 | " or bigger than %dk %llu %d\n", chunk_size, | |
470 | (unsigned long long)bio->bi_sector, bio->bi_size >> 10); | |
471 | ||
6712ecf8 | 472 | bio_io_error(bio); |
1da177e4 LT |
473 | return 0; |
474 | } | |
475 | ||
476 | static void raid0_status (struct seq_file *seq, mddev_t *mddev) | |
477 | { | |
478 | #undef MD_DEBUG | |
479 | #ifdef MD_DEBUG | |
480 | int j, k, h; | |
481 | char b[BDEVNAME_SIZE]; | |
482 | raid0_conf_t *conf = mddev_to_conf(mddev); | |
483 | ||
484 | h = 0; | |
485 | for (j = 0; j < conf->nr_strip_zones; j++) { | |
486 | seq_printf(seq, " z%d", j); | |
487 | if (conf->hash_table[h] == conf->strip_zone+j) | |
488 | seq_printf("(h%d)", h++); | |
489 | seq_printf(seq, "=["); | |
490 | for (k = 0; k < conf->strip_zone[j].nb_dev; k++) | |
491 | seq_printf (seq, "%s/", bdevname( | |
492 | conf->strip_zone[j].dev[k]->bdev,b)); | |
493 | ||
494 | seq_printf (seq, "] zo=%d do=%d s=%d\n", | |
495 | conf->strip_zone[j].zone_offset, | |
496 | conf->strip_zone[j].dev_offset, | |
497 | conf->strip_zone[j].size); | |
498 | } | |
499 | #endif | |
500 | seq_printf(seq, " %dk chunks", mddev->chunk_size/1024); | |
501 | return; | |
502 | } | |
503 | ||
2604b703 | 504 | static struct mdk_personality raid0_personality= |
1da177e4 LT |
505 | { |
506 | .name = "raid0", | |
2604b703 | 507 | .level = 0, |
1da177e4 LT |
508 | .owner = THIS_MODULE, |
509 | .make_request = raid0_make_request, | |
510 | .run = raid0_run, | |
511 | .stop = raid0_stop, | |
512 | .status = raid0_status, | |
513 | }; | |
514 | ||
515 | static int __init raid0_init (void) | |
516 | { | |
2604b703 | 517 | return register_md_personality (&raid0_personality); |
1da177e4 LT |
518 | } |
519 | ||
520 | static void raid0_exit (void) | |
521 | { | |
2604b703 | 522 | unregister_md_personality (&raid0_personality); |
1da177e4 LT |
523 | } |
524 | ||
525 | module_init(raid0_init); | |
526 | module_exit(raid0_exit); | |
527 | MODULE_LICENSE("GPL"); | |
528 | MODULE_ALIAS("md-personality-2"); /* RAID0 */ | |
d9d166c2 | 529 | MODULE_ALIAS("md-raid0"); |
2604b703 | 530 | MODULE_ALIAS("md-level-0"); |