blob: dfe32149ad3ae1b0caf77fc39003d82cb640f3f7 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
28static void raid0_unplug(request_queue_t *q)
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++) {
36 request_queue_t *r_queue = bdev_get_queue(devlist[i]->bdev);
37
38 if (r_queue->unplug_fn)
39 r_queue->unplug_fn(r_queue);
40 }
41}
42
43static int raid0_issue_flush(request_queue_t *q, struct gendisk *disk,
44 sector_t *error_sector)
45{
46 mddev_t *mddev = q->queuedata;
47 raid0_conf_t *conf = mddev_to_conf(mddev);
48 mdk_rdev_t **devlist = conf->strip_zone[0].dev;
49 int i, ret = 0;
50
51 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
52 struct block_device *bdev = devlist[i]->bdev;
53 request_queue_t *r_queue = bdev_get_queue(bdev);
54
55 if (!r_queue->issue_flush_fn)
56 ret = -EOPNOTSUPP;
57 else
58 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
59 }
60 return ret;
61}
62
NeilBrown26be34d2006-10-03 01:15:53 -070063static int raid0_congested(void *data, int bits)
64{
65 mddev_t *mddev = data;
66 raid0_conf_t *conf = mddev_to_conf(mddev);
67 mdk_rdev_t **devlist = conf->strip_zone[0].dev;
68 int i, ret = 0;
69
70 for (i = 0; i < mddev->raid_disks && !ret ; i++) {
71 request_queue_t *q = bdev_get_queue(devlist[i]->bdev);
72
73 ret |= bdi_congested(&q->backing_dev_info, bits);
74 }
75 return ret;
76}
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79static int create_strip_zones (mddev_t *mddev)
80{
81 int i, c, j;
82 sector_t current_offset, curr_zone_offset;
83 sector_t min_spacing;
84 raid0_conf_t *conf = mddev_to_conf(mddev);
85 mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
86 struct list_head *tmp1, *tmp2;
87 struct strip_zone *zone;
88 int cnt;
89 char b[BDEVNAME_SIZE];
90
91 /*
92 * The number of 'same size groups'
93 */
94 conf->nr_strip_zones = 0;
95
96 ITERATE_RDEV(mddev,rdev1,tmp1) {
97 printk("raid0: looking at %s\n",
98 bdevname(rdev1->bdev,b));
99 c = 0;
100 ITERATE_RDEV(mddev,rdev2,tmp2) {
101 printk("raid0: comparing %s(%llu)",
102 bdevname(rdev1->bdev,b),
103 (unsigned long long)rdev1->size);
104 printk(" with %s(%llu)\n",
105 bdevname(rdev2->bdev,b),
106 (unsigned long long)rdev2->size);
107 if (rdev2 == rdev1) {
108 printk("raid0: END\n");
109 break;
110 }
111 if (rdev2->size == rdev1->size)
112 {
113 /*
114 * Not unique, don't count it as a new
115 * group
116 */
117 printk("raid0: EQUAL\n");
118 c = 1;
119 break;
120 }
121 printk("raid0: NOT EQUAL\n");
122 }
123 if (!c) {
124 printk("raid0: ==> UNIQUE\n");
125 conf->nr_strip_zones++;
126 printk("raid0: %d zones\n", conf->nr_strip_zones);
127 }
128 }
129 printk("raid0: FINAL %d zones\n", conf->nr_strip_zones);
130
NeilBrown9ffae0c2006-01-06 00:20:32 -0800131 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 conf->nr_strip_zones, GFP_KERNEL);
133 if (!conf->strip_zone)
134 return 1;
NeilBrown9ffae0c2006-01-06 00:20:32 -0800135 conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 conf->nr_strip_zones*mddev->raid_disks,
137 GFP_KERNEL);
138 if (!conf->devlist)
139 return 1;
140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 /* The first zone must contain all devices, so here we check that
142 * there is a proper alignment of slots to devices and find them all
143 */
144 zone = &conf->strip_zone[0];
145 cnt = 0;
146 smallest = NULL;
147 zone->dev = conf->devlist;
148 ITERATE_RDEV(mddev, rdev1, tmp1) {
149 int j = rdev1->raid_disk;
150
151 if (j < 0 || j >= mddev->raid_disks) {
152 printk("raid0: bad disk number %d - aborting!\n", j);
153 goto abort;
154 }
155 if (zone->dev[j]) {
156 printk("raid0: multiple devices for %d - aborting!\n",
157 j);
158 goto abort;
159 }
160 zone->dev[j] = rdev1;
161
162 blk_queue_stack_limits(mddev->queue,
163 rdev1->bdev->bd_disk->queue);
164 /* as we don't honour merge_bvec_fn, we must never risk
165 * violating it, so limit ->max_sector to one PAGE, as
166 * a one page request is never in violation.
167 */
168
169 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn &&
170 mddev->queue->max_sectors > (PAGE_SIZE>>9))
171 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
172
173 if (!smallest || (rdev1->size <smallest->size))
174 smallest = rdev1;
175 cnt++;
176 }
177 if (cnt != mddev->raid_disks) {
178 printk("raid0: too few disks (%d of %d) - aborting!\n",
179 cnt, mddev->raid_disks);
180 goto abort;
181 }
182 zone->nb_dev = cnt;
183 zone->size = smallest->size * cnt;
184 zone->zone_offset = 0;
185
186 current_offset = smallest->size;
187 curr_zone_offset = zone->size;
188
189 /* now do the other zones */
190 for (i = 1; i < conf->nr_strip_zones; i++)
191 {
192 zone = conf->strip_zone + i;
193 zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks;
194
195 printk("raid0: zone %d\n", i);
196 zone->dev_offset = current_offset;
197 smallest = NULL;
198 c = 0;
199
200 for (j=0; j<cnt; j++) {
201 char b[BDEVNAME_SIZE];
202 rdev = conf->strip_zone[0].dev[j];
203 printk("raid0: checking %s ...", bdevname(rdev->bdev,b));
204 if (rdev->size > current_offset)
205 {
206 printk(" contained as device %d\n", c);
207 zone->dev[c] = rdev;
208 c++;
209 if (!smallest || (rdev->size <smallest->size)) {
210 smallest = rdev;
211 printk(" (%llu) is smallest!.\n",
212 (unsigned long long)rdev->size);
213 }
214 } else
215 printk(" nope.\n");
216 }
217
218 zone->nb_dev = c;
219 zone->size = (smallest->size - current_offset) * c;
220 printk("raid0: zone->nb_dev: %d, size: %llu\n",
221 zone->nb_dev, (unsigned long long)zone->size);
222
223 zone->zone_offset = curr_zone_offset;
224 curr_zone_offset += zone->size;
225
226 current_offset = smallest->size;
227 printk("raid0: current zone offset: %llu\n",
228 (unsigned long long)current_offset);
229 }
230
231 /* Now find appropriate hash spacing.
232 * We want a number which causes most hash entries to cover
233 * at most two strips, but the hash table must be at most
234 * 1 PAGE. We choose the smallest strip, or contiguous collection
235 * of strips, that has big enough size. We never consider the last
236 * strip though as it's size has no bearing on the efficacy of the hash
237 * table.
238 */
239 conf->hash_spacing = curr_zone_offset;
240 min_spacing = curr_zone_offset;
241 sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
242 for (i=0; i < conf->nr_strip_zones-1; i++) {
243 sector_t sz = 0;
244 for (j=i; j<conf->nr_strip_zones-1 &&
245 sz < min_spacing ; j++)
246 sz += conf->strip_zone[j].size;
247 if (sz >= min_spacing && sz < conf->hash_spacing)
248 conf->hash_spacing = sz;
249 }
250
251 mddev->queue->unplug_fn = raid0_unplug;
252
253 mddev->queue->issue_flush_fn = raid0_issue_flush;
NeilBrown26be34d2006-10-03 01:15:53 -0700254 mddev->queue->backing_dev_info.congested_fn = raid0_congested;
255 mddev->queue->backing_dev_info.congested_data = mddev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
257 printk("raid0: done.\n");
258 return 0;
259 abort:
260 return 1;
261}
262
263/**
264 * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
265 * @q: request queue
266 * @bio: the buffer head that's been built up so far
267 * @biovec: the request that could be merged to it.
268 *
269 * Return amount of bytes we can accept at this offset
270 */
271static int raid0_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec)
272{
273 mddev_t *mddev = q->queuedata;
274 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
275 int max;
276 unsigned int chunk_sectors = mddev->chunk_size >> 9;
277 unsigned int bio_sectors = bio->bi_size >> 9;
278
279 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
280 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
281 if (max <= biovec->bv_len && bio_sectors == 0)
282 return biovec->bv_len;
283 else
284 return max;
285}
286
287static int raid0_run (mddev_t *mddev)
288{
289 unsigned cur=0, i=0, nb_zone;
290 s64 size;
291 raid0_conf_t *conf;
292 mdk_rdev_t *rdev;
293 struct list_head *tmp;
294
NeilBrown2604b702006-01-06 00:20:36 -0800295 if (mddev->chunk_size == 0) {
296 printk(KERN_ERR "md/raid0: non-zero chunk size required.\n");
297 return -EINVAL;
298 }
299 printk(KERN_INFO "%s: setting max_sectors to %d, segment boundary to %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 mdname(mddev),
301 mddev->chunk_size >> 9,
302 (mddev->chunk_size>>1)-1);
303 blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
304 blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1);
305
306 conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL);
307 if (!conf)
308 goto out;
309 mddev->private = (void *)conf;
310
311 conf->strip_zone = NULL;
312 conf->devlist = NULL;
313 if (create_strip_zones (mddev))
314 goto out_free_conf;
315
316 /* calculate array device size */
317 mddev->array_size = 0;
318 ITERATE_RDEV(mddev,rdev,tmp)
319 mddev->array_size += rdev->size;
320
321 printk("raid0 : md_size is %llu blocks.\n",
322 (unsigned long long)mddev->array_size);
323 printk("raid0 : conf->hash_spacing is %llu blocks.\n",
324 (unsigned long long)conf->hash_spacing);
325 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 sector_t s = mddev->array_size;
327 sector_t space = conf->hash_spacing;
328 int round;
329 conf->preshift = 0;
Neil Brown1eb29122005-07-15 03:56:27 -0700330 if (sizeof(sector_t) > sizeof(u32)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 /*shift down space and s so that sector_div will work */
Neil Brown1eb29122005-07-15 03:56:27 -0700332 while (space > (sector_t) (~(u32)0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 s >>= 1;
334 space >>= 1;
335 s += 1; /* force round-up */
336 conf->preshift++;
337 }
338 }
Neil Brown1eb29122005-07-15 03:56:27 -0700339 round = sector_div(s, (u32)space) ? 1 : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 nb_zone = s + round;
341 }
342 printk("raid0 : nb_zone is %d.\n", nb_zone);
343
344 printk("raid0 : Allocating %Zd bytes for hash.\n",
345 nb_zone*sizeof(struct strip_zone*));
346 conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL);
347 if (!conf->hash_table)
348 goto out_free_conf;
349 size = conf->strip_zone[cur].size;
350
NeilBrown5c4c3332006-05-22 22:35:26 -0700351 conf->hash_table[0] = conf->strip_zone + cur;
352 for (i=1; i< nb_zone; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 while (size <= conf->hash_spacing) {
354 cur++;
355 size += conf->strip_zone[cur].size;
356 }
357 size -= conf->hash_spacing;
NeilBrown5c4c3332006-05-22 22:35:26 -0700358 conf->hash_table[i] = conf->strip_zone + cur;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 }
360 if (conf->preshift) {
361 conf->hash_spacing >>= conf->preshift;
362 /* round hash_spacing up so when we divide by it, we
363 * err on the side of too-low, which is safest
364 */
365 conf->hash_spacing++;
366 }
367
368 /* calculate the max read-ahead size.
369 * For read-ahead of large files to be effective, we need to
370 * readahead at least twice a whole stripe. i.e. number of devices
371 * multiplied by chunk size times 2.
372 * If an individual device has an ra_pages greater than the
373 * chunk size, then we will not drive that device as hard as it
374 * wants. We consider this a configuration error: a larger
375 * chunksize should be used in that case.
376 */
377 {
NeilBrown2d1f3b52006-01-06 00:20:31 -0800378 int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
380 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
381 }
382
383
384 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
385 return 0;
386
387out_free_conf:
Jesper Juhl990a8ba2005-06-21 17:17:30 -0700388 kfree(conf->strip_zone);
389 kfree(conf->devlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 kfree(conf);
391 mddev->private = NULL;
392out:
NeilBrown29fc7e32006-02-03 03:03:41 -0800393 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394}
395
396static int raid0_stop (mddev_t *mddev)
397{
398 raid0_conf_t *conf = mddev_to_conf(mddev);
399
400 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
Jesper Juhl990a8ba2005-06-21 17:17:30 -0700401 kfree(conf->hash_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 conf->hash_table = NULL;
Jesper Juhl990a8ba2005-06-21 17:17:30 -0700403 kfree(conf->strip_zone);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 conf->strip_zone = NULL;
Jesper Juhl990a8ba2005-06-21 17:17:30 -0700405 kfree(conf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 mddev->private = NULL;
407
408 return 0;
409}
410
411static int raid0_make_request (request_queue_t *q, struct bio *bio)
412{
413 mddev_t *mddev = q->queuedata;
414 unsigned int sect_in_chunk, chunksize_bits, chunk_size, chunk_sects;
415 raid0_conf_t *conf = mddev_to_conf(mddev);
416 struct strip_zone *zone;
417 mdk_rdev_t *tmp_dev;
418 unsigned long chunk;
419 sector_t block, rsect;
Jens Axboea3623572005-11-01 09:26:16 +0100420 const int rw = bio_data_dir(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421
NeilBrowne5dcdd82005-09-09 16:23:41 -0700422 if (unlikely(bio_barrier(bio))) {
423 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
424 return 0;
425 }
426
Jens Axboea3623572005-11-01 09:26:16 +0100427 disk_stat_inc(mddev->gendisk, ios[rw]);
428 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429
430 chunk_size = mddev->chunk_size >> 10;
431 chunk_sects = mddev->chunk_size >> 9;
432 chunksize_bits = ffz(~chunk_size);
433 block = bio->bi_sector >> 1;
434
435
436 if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
437 struct bio_pair *bp;
438 /* Sanity check -- queue functions should prevent this happening */
439 if (bio->bi_vcnt != 1 ||
440 bio->bi_idx != 0)
441 goto bad_map;
442 /* This is a one page bio that upper layers
443 * refuse to split for us, so we need to split it.
444 */
445 bp = bio_split(bio, bio_split_pool, chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
446 if (raid0_make_request(q, &bp->bio1))
447 generic_make_request(&bp->bio1);
448 if (raid0_make_request(q, &bp->bio2))
449 generic_make_request(&bp->bio2);
450
451 bio_pair_release(bp);
452 return 0;
453 }
454
455
456 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 sector_t x = block >> conf->preshift;
Neil Brown1eb29122005-07-15 03:56:27 -0700458 sector_div(x, (u32)conf->hash_spacing);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 zone = conf->hash_table[x];
460 }
461
462 while (block >= (zone->zone_offset + zone->size))
463 zone++;
464
465 sect_in_chunk = bio->bi_sector & ((chunk_size<<1) -1);
466
467
468 {
469 sector_t x = (block - zone->zone_offset) >> chunksize_bits;
470
471 sector_div(x, zone->nb_dev);
472 chunk = x;
473 BUG_ON(x != (sector_t)chunk);
474
475 x = block >> chunksize_bits;
476 tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];
477 }
478 rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1)
479 + sect_in_chunk;
480
481 bio->bi_bdev = tmp_dev->bdev;
482 bio->bi_sector = rsect + tmp_dev->data_offset;
483
484 /*
485 * Let the main block layer submit the IO and resolve recursion:
486 */
487 return 1;
488
489bad_map:
490 printk("raid0_make_request bug: can't convert block across chunks"
491 " or bigger than %dk %llu %d\n", chunk_size,
492 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
493
494 bio_io_error(bio, bio->bi_size);
495 return 0;
496}
497
498static void raid0_status (struct seq_file *seq, mddev_t *mddev)
499{
500#undef MD_DEBUG
501#ifdef MD_DEBUG
502 int j, k, h;
503 char b[BDEVNAME_SIZE];
504 raid0_conf_t *conf = mddev_to_conf(mddev);
505
506 h = 0;
507 for (j = 0; j < conf->nr_strip_zones; j++) {
508 seq_printf(seq, " z%d", j);
509 if (conf->hash_table[h] == conf->strip_zone+j)
510 seq_printf("(h%d)", h++);
511 seq_printf(seq, "=[");
512 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
513 seq_printf (seq, "%s/", bdevname(
514 conf->strip_zone[j].dev[k]->bdev,b));
515
516 seq_printf (seq, "] zo=%d do=%d s=%d\n",
517 conf->strip_zone[j].zone_offset,
518 conf->strip_zone[j].dev_offset,
519 conf->strip_zone[j].size);
520 }
521#endif
522 seq_printf(seq, " %dk chunks", mddev->chunk_size/1024);
523 return;
524}
525
NeilBrown2604b702006-01-06 00:20:36 -0800526static struct mdk_personality raid0_personality=
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527{
528 .name = "raid0",
NeilBrown2604b702006-01-06 00:20:36 -0800529 .level = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 .owner = THIS_MODULE,
531 .make_request = raid0_make_request,
532 .run = raid0_run,
533 .stop = raid0_stop,
534 .status = raid0_status,
535};
536
537static int __init raid0_init (void)
538{
NeilBrown2604b702006-01-06 00:20:36 -0800539 return register_md_personality (&raid0_personality);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540}
541
542static void raid0_exit (void)
543{
NeilBrown2604b702006-01-06 00:20:36 -0800544 unregister_md_personality (&raid0_personality);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545}
546
547module_init(raid0_init);
548module_exit(raid0_exit);
549MODULE_LICENSE("GPL");
550MODULE_ALIAS("md-personality-2"); /* RAID0 */
NeilBrownd9d166c2006-01-06 00:20:51 -0800551MODULE_ALIAS("md-raid0");
NeilBrown2604b702006-01-06 00:20:36 -0800552MODULE_ALIAS("md-level-0");