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dccp: replace min/casting by min_t
[linux-2.6/btrfs-unstable.git] / drivers / md / raid0.c
blobba6b85de96d209635e640efb19a6569bfd9e8a38
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 RAID-0 management functions.
9
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2, or (at your option)
13 any later version.
14
15 You should have received a copy of the GNU General Public License
16 (for example /usr/src/linux/COPYING); if not, write to the Free
17 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19
20 #include <linux/blkdev.h>
21 #include <linux/seq_file.h>
22 #include <linux/module.h>
23 #include <linux/slab.h>
24 #include "md.h"
25 #include "raid0.h"
26 #include "raid5.h"
27
28 static int raid0_congested(void *data, int bits)
29 {
30 struct mddev *mddev = data;
31 struct r0conf *conf = mddev->private;
32 struct md_rdev **devlist = conf->devlist;
33 int raid_disks = conf->strip_zone[0].nb_dev;
34 int i, ret = 0;
35
36 if (mddev_congested(mddev, bits))
37 return 1;
38
39 for (i = 0; i < raid_disks && !ret ; i++) {
40 struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
41
42 ret |= bdi_congested(&q->backing_dev_info, bits);
43 }
44 return ret;
45 }
46
47 /*
48 * inform the user of the raid configuration
49 */
50 static void dump_zones(struct mddev *mddev)
51 {
52 int j, k;
53 sector_t zone_size = 0;
54 sector_t zone_start = 0;
55 char b[BDEVNAME_SIZE];
56 struct r0conf *conf = mddev->private;
57 int raid_disks = conf->strip_zone[0].nb_dev;
58 printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n",
59 mdname(mddev),
60 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
61 for (j = 0; j < conf->nr_strip_zones; j++) {
62 printk(KERN_INFO "md: zone%d=[", j);
63 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
64 printk(KERN_CONT "%s%s", k?"/":"",
65 bdevname(conf->devlist[j*raid_disks
66 + k]->bdev, b));
67 printk(KERN_CONT "]\n");
68
69 zone_size = conf->strip_zone[j].zone_end - zone_start;
70 printk(KERN_INFO " zone-offset=%10lluKB, "
71 "device-offset=%10lluKB, size=%10lluKB\n",
72 (unsigned long long)zone_start>>1,
73 (unsigned long long)conf->strip_zone[j].dev_start>>1,
74 (unsigned long long)zone_size>>1);
75 zone_start = conf->strip_zone[j].zone_end;
76 }
77 printk(KERN_INFO "\n");
78 }
79
80 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
81 {
82 int i, c, err;
83 sector_t curr_zone_end, sectors;
84 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
85 struct strip_zone *zone;
86 int cnt;
87 char b[BDEVNAME_SIZE];
88 char b2[BDEVNAME_SIZE];
89 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
90 bool discard_supported = false;
91
92 if (!conf)
93 return -ENOMEM;
94 rdev_for_each(rdev1, mddev) {
95 pr_debug("md/raid0:%s: looking at %s\n",
96 mdname(mddev),
97 bdevname(rdev1->bdev, b));
98 c = 0;
99
100 /* round size to chunk_size */
101 sectors = rdev1->sectors;
102 sector_div(sectors, mddev->chunk_sectors);
103 rdev1->sectors = sectors * mddev->chunk_sectors;
104
105 rdev_for_each(rdev2, mddev) {
106 pr_debug("md/raid0:%s: comparing %s(%llu)"
107 " with %s(%llu)\n",
108 mdname(mddev),
109 bdevname(rdev1->bdev,b),
110 (unsigned long long)rdev1->sectors,
111 bdevname(rdev2->bdev,b2),
112 (unsigned long long)rdev2->sectors);
113 if (rdev2 == rdev1) {
114 pr_debug("md/raid0:%s: END\n",
115 mdname(mddev));
116 break;
117 }
118 if (rdev2->sectors == rdev1->sectors) {
119 /*
120 * Not unique, don't count it as a new
121 * group
122 */
123 pr_debug("md/raid0:%s: EQUAL\n",
124 mdname(mddev));
125 c = 1;
126 break;
127 }
128 pr_debug("md/raid0:%s: NOT EQUAL\n",
129 mdname(mddev));
130 }
131 if (!c) {
132 pr_debug("md/raid0:%s: ==> UNIQUE\n",
133 mdname(mddev));
134 conf->nr_strip_zones++;
135 pr_debug("md/raid0:%s: %d zones\n",
136 mdname(mddev), conf->nr_strip_zones);
137 }
138 }
139 pr_debug("md/raid0:%s: FINAL %d zones\n",
140 mdname(mddev), conf->nr_strip_zones);
141 err = -ENOMEM;
142 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
143 conf->nr_strip_zones, GFP_KERNEL);
144 if (!conf->strip_zone)
145 goto abort;
146 conf->devlist = kzalloc(sizeof(struct md_rdev*)*
147 conf->nr_strip_zones*mddev->raid_disks,
148 GFP_KERNEL);
149 if (!conf->devlist)
150 goto abort;
151
152 /* The first zone must contain all devices, so here we check that
153 * there is a proper alignment of slots to devices and find them all
154 */
155 zone = &conf->strip_zone[0];
156 cnt = 0;
157 smallest = NULL;
158 dev = conf->devlist;
159 err = -EINVAL;
160 rdev_for_each(rdev1, mddev) {
161 int j = rdev1->raid_disk;
162
163 if (mddev->level == 10) {
164 /* taking over a raid10-n2 array */
165 j /= 2;
166 rdev1->new_raid_disk = j;
167 }
168
169 if (mddev->level == 1) {
170 /* taiking over a raid1 array-
171 * we have only one active disk
172 */
173 j = 0;
174 rdev1->new_raid_disk = j;
175 }
176
177 if (j < 0) {
178 printk(KERN_ERR
179 "md/raid0:%s: remove inactive devices before converting to RAID0\n",
180 mdname(mddev));
181 goto abort;
182 }
183 if (j >= mddev->raid_disks) {
184 printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
185 "aborting!\n", mdname(mddev), j);
186 goto abort;
187 }
188 if (dev[j]) {
189 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
190 "aborting!\n", mdname(mddev), j);
191 goto abort;
192 }
193 dev[j] = rdev1;
194
195 disk_stack_limits(mddev->gendisk, rdev1->bdev,
196 rdev1->data_offset << 9);
197
198 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)
199 conf->has_merge_bvec = 1;
200
201 if (!smallest || (rdev1->sectors < smallest->sectors))
202 smallest = rdev1;
203 cnt++;
204
205 if (blk_queue_discard(bdev_get_queue(rdev1->bdev)))
206 discard_supported = true;
207 }
208 if (cnt != mddev->raid_disks) {
209 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - "
210 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks);
211 goto abort;
212 }
213 zone->nb_dev = cnt;
214 zone->zone_end = smallest->sectors * cnt;
215
216 curr_zone_end = zone->zone_end;
217
218 /* now do the other zones */
219 for (i = 1; i < conf->nr_strip_zones; i++)
220 {
221 int j;
222
223 zone = conf->strip_zone + i;
224 dev = conf->devlist + i * mddev->raid_disks;
225
226 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
227 zone->dev_start = smallest->sectors;
228 smallest = NULL;
229 c = 0;
230
231 for (j=0; j<cnt; j++) {
232 rdev = conf->devlist[j];
233 if (rdev->sectors <= zone->dev_start) {
234 pr_debug("md/raid0:%s: checking %s ... nope\n",
235 mdname(mddev),
236 bdevname(rdev->bdev, b));
237 continue;
238 }
239 pr_debug("md/raid0:%s: checking %s ..."
240 " contained as device %d\n",
241 mdname(mddev),
242 bdevname(rdev->bdev, b), c);
243 dev[c] = rdev;
244 c++;
245 if (!smallest || rdev->sectors < smallest->sectors) {
246 smallest = rdev;
247 pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
248 mdname(mddev),
249 (unsigned long long)rdev->sectors);
250 }
251 }
252
253 zone->nb_dev = c;
254 sectors = (smallest->sectors - zone->dev_start) * c;
255 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
256 mdname(mddev),
257 zone->nb_dev, (unsigned long long)sectors);
258
259 curr_zone_end += sectors;
260 zone->zone_end = curr_zone_end;
261
262 pr_debug("md/raid0:%s: current zone start: %llu\n",
263 mdname(mddev),
264 (unsigned long long)smallest->sectors);
265 }
266 mddev->queue->backing_dev_info.congested_fn = raid0_congested;
267 mddev->queue->backing_dev_info.congested_data = mddev;
268
269 /*
270 * now since we have the hard sector sizes, we can make sure
271 * chunk size is a multiple of that sector size
272 */
273 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
274 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
275 mdname(mddev),
276 mddev->chunk_sectors << 9);
277 goto abort;
278 }
279
280 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
281 blk_queue_io_opt(mddev->queue,
282 (mddev->chunk_sectors << 9) * mddev->raid_disks);
283
284 if (!discard_supported)
285 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
286 else
287 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
288
289 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
290 *private_conf = conf;
291
292 return 0;
293 abort:
294 kfree(conf->strip_zone);
295 kfree(conf->devlist);
296 kfree(conf);
297 *private_conf = ERR_PTR(err);
298 return err;
299 }
300
301 /* Find the zone which holds a particular offset
302 * Update *sectorp to be an offset in that zone
303 */
304 static struct strip_zone *find_zone(struct r0conf *conf,
305 sector_t *sectorp)
306 {
307 int i;
308 struct strip_zone *z = conf->strip_zone;
309 sector_t sector = *sectorp;
310
311 for (i = 0; i < conf->nr_strip_zones; i++)
312 if (sector < z[i].zone_end) {
313 if (i)
314 *sectorp = sector - z[i-1].zone_end;
315 return z + i;
316 }
317 BUG();
318 }
319
320 /*
321 * remaps the bio to the target device. we separate two flows.
322 * power 2 flow and a general flow for the sake of perfromance
323 */
324 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
325 sector_t sector, sector_t *sector_offset)
326 {
327 unsigned int sect_in_chunk;
328 sector_t chunk;
329 struct r0conf *conf = mddev->private;
330 int raid_disks = conf->strip_zone[0].nb_dev;
331 unsigned int chunk_sects = mddev->chunk_sectors;
332
333 if (is_power_of_2(chunk_sects)) {
334 int chunksect_bits = ffz(~chunk_sects);
335 /* find the sector offset inside the chunk */
336 sect_in_chunk = sector & (chunk_sects - 1);
337 sector >>= chunksect_bits;
338 /* chunk in zone */
339 chunk = *sector_offset;
340 /* quotient is the chunk in real device*/
341 sector_div(chunk, zone->nb_dev << chunksect_bits);
342 } else{
343 sect_in_chunk = sector_div(sector, chunk_sects);
344 chunk = *sector_offset;
345 sector_div(chunk, chunk_sects * zone->nb_dev);
346 }
347 /*
348 * position the bio over the real device
349 * real sector = chunk in device + starting of zone
350 * + the position in the chunk
351 */
352 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
353 return conf->devlist[(zone - conf->strip_zone)*raid_disks
354 + sector_div(sector, zone->nb_dev)];
355 }
356
357 /**
358 * raid0_mergeable_bvec -- tell bio layer if two requests can be merged
359 * @q: request queue
360 * @bvm: properties of new bio
361 * @biovec: the request that could be merged to it.
362 *
363 * Return amount of bytes we can accept at this offset
364 */
365 static int raid0_mergeable_bvec(struct request_queue *q,
366 struct bvec_merge_data *bvm,
367 struct bio_vec *biovec)
368 {
369 struct mddev *mddev = q->queuedata;
370 struct r0conf *conf = mddev->private;
371 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
372 sector_t sector_offset = sector;
373 int max;
374 unsigned int chunk_sectors = mddev->chunk_sectors;
375 unsigned int bio_sectors = bvm->bi_size >> 9;
376 struct strip_zone *zone;
377 struct md_rdev *rdev;
378 struct request_queue *subq;
379
380 if (is_power_of_2(chunk_sectors))
381 max = (chunk_sectors - ((sector & (chunk_sectors-1))
382 + bio_sectors)) << 9;
383 else
384 max = (chunk_sectors - (sector_div(sector, chunk_sectors)
385 + bio_sectors)) << 9;
386 if (max < 0)
387 max = 0; /* bio_add cannot handle a negative return */
388 if (max <= biovec->bv_len && bio_sectors == 0)
389 return biovec->bv_len;
390 if (max < biovec->bv_len)
391 /* too small already, no need to check further */
392 return max;
393 if (!conf->has_merge_bvec)
394 return max;
395
396 /* May need to check subordinate device */
397 sector = sector_offset;
398 zone = find_zone(mddev->private, &sector_offset);
399 rdev = map_sector(mddev, zone, sector, &sector_offset);
400 subq = bdev_get_queue(rdev->bdev);
401 if (subq->merge_bvec_fn) {
402 bvm->bi_bdev = rdev->bdev;
403 bvm->bi_sector = sector_offset + zone->dev_start +
404 rdev->data_offset;
405 return min(max, subq->merge_bvec_fn(subq, bvm, biovec));
406 } else
407 return max;
408 }
409
410 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
411 {
412 sector_t array_sectors = 0;
413 struct md_rdev *rdev;
414
415 WARN_ONCE(sectors || raid_disks,
416 "%s does not support generic reshape\n", __func__);
417
418 rdev_for_each(rdev, mddev)
419 array_sectors += (rdev->sectors &
420 ~(sector_t)(mddev->chunk_sectors-1));
421
422 return array_sectors;
423 }
424
425 static int raid0_stop(struct mddev *mddev);
426
427 static int raid0_run(struct mddev *mddev)
428 {
429 struct r0conf *conf;
430 int ret;
431
432 if (mddev->chunk_sectors == 0) {
433 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
434 mdname(mddev));
435 return -EINVAL;
436 }
437 if (md_check_no_bitmap(mddev))
438 return -EINVAL;
439 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
440 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
441 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);
442
443 /* if private is not null, we are here after takeover */
444 if (mddev->private == NULL) {
445 ret = create_strip_zones(mddev, &conf);
446 if (ret < 0)
447 return ret;
448 mddev->private = conf;
449 }
450 conf = mddev->private;
451
452 /* calculate array device size */
453 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
454
455 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
456 mdname(mddev),
457 (unsigned long long)mddev->array_sectors);
458 /* calculate the max read-ahead size.
459 * For read-ahead of large files to be effective, we need to
460 * readahead at least twice a whole stripe. i.e. number of devices
461 * multiplied by chunk size times 2.
462 * If an individual device has an ra_pages greater than the
463 * chunk size, then we will not drive that device as hard as it
464 * wants. We consider this a configuration error: a larger
465 * chunksize should be used in that case.
466 */
467 {
468 int stripe = mddev->raid_disks *
469 (mddev->chunk_sectors << 9) / PAGE_SIZE;
470 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
471 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
472 }
473
474 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
475 dump_zones(mddev);
476
477 ret = md_integrity_register(mddev);
478 if (ret)
479 raid0_stop(mddev);
480
481 return ret;
482 }
483
484 static int raid0_stop(struct mddev *mddev)
485 {
486 struct r0conf *conf = mddev->private;
487
488 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
489 kfree(conf->strip_zone);
490 kfree(conf->devlist);
491 kfree(conf);
492 mddev->private = NULL;
493 return 0;
494 }
495
496 /*
497 * Is io distribute over 1 or more chunks ?
498 */
499 static inline int is_io_in_chunk_boundary(struct mddev *mddev,
500 unsigned int chunk_sects, struct bio *bio)
501 {
502 if (likely(is_power_of_2(chunk_sects))) {
503 return chunk_sects >=
504 ((bio->bi_iter.bi_sector & (chunk_sects-1))
505 + bio_sectors(bio));
506 } else{
507 sector_t sector = bio->bi_iter.bi_sector;
508 return chunk_sects >= (sector_div(sector, chunk_sects)
509 + bio_sectors(bio));
510 }
511 }
512
513 static void raid0_make_request(struct mddev *mddev, struct bio *bio)
514 {
515 struct strip_zone *zone;
516 struct md_rdev *tmp_dev;
517 struct bio *split;
518
519 if (unlikely(bio->bi_rw & REQ_FLUSH)) {
520 md_flush_request(mddev, bio);
521 return;
522 }
523
524 do {
525 sector_t sector = bio->bi_iter.bi_sector;
526 unsigned chunk_sects = mddev->chunk_sectors;
527
528 unsigned sectors = chunk_sects -
529 (likely(is_power_of_2(chunk_sects))
530 ? (sector & (chunk_sects-1))
531 : sector_div(sector, chunk_sects));
532
533 if (sectors < bio_sectors(bio)) {
534 split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
535 bio_chain(split, bio);
536 } else {
537 split = bio;
538 }
539
540 zone = find_zone(mddev->private, &sector);
541 tmp_dev = map_sector(mddev, zone, sector, &sector);
542 split->bi_bdev = tmp_dev->bdev;
543 split->bi_iter.bi_sector = sector + zone->dev_start +
544 tmp_dev->data_offset;
545
546 if (unlikely((split->bi_rw & REQ_DISCARD) &&
547 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
548 /* Just ignore it */
549 bio_endio(split, 0);
550 } else
551 generic_make_request(split);
552 } while (split != bio);
553 }
554
555 static void raid0_status(struct seq_file *seq, struct mddev *mddev)
556 {
557 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
558 return;
559 }
560
561 static void *raid0_takeover_raid45(struct mddev *mddev)
562 {
563 struct md_rdev *rdev;
564 struct r0conf *priv_conf;
565
566 if (mddev->degraded != 1) {
567 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
568 mdname(mddev),
569 mddev->degraded);
570 return ERR_PTR(-EINVAL);
571 }
572
573 rdev_for_each(rdev, mddev) {
574 /* check slot number for a disk */
575 if (rdev->raid_disk == mddev->raid_disks-1) {
576 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
577 mdname(mddev));
578 return ERR_PTR(-EINVAL);
579 }
580 rdev->sectors = mddev->dev_sectors;
581 }
582
583 /* Set new parameters */
584 mddev->new_level = 0;
585 mddev->new_layout = 0;
586 mddev->new_chunk_sectors = mddev->chunk_sectors;
587 mddev->raid_disks--;
588 mddev->delta_disks = -1;
589 /* make sure it will be not marked as dirty */
590 mddev->recovery_cp = MaxSector;
591
592 create_strip_zones(mddev, &priv_conf);
593 return priv_conf;
594 }
595
596 static void *raid0_takeover_raid10(struct mddev *mddev)
597 {
598 struct r0conf *priv_conf;
599
600 /* Check layout:
601 * - far_copies must be 1
602 * - near_copies must be 2
603 * - disks number must be even
604 * - all mirrors must be already degraded
605 */
606 if (mddev->layout != ((1 << 8) + 2)) {
607 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n",
608 mdname(mddev),
609 mddev->layout);
610 return ERR_PTR(-EINVAL);
611 }
612 if (mddev->raid_disks & 1) {
613 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n",
614 mdname(mddev));
615 return ERR_PTR(-EINVAL);
616 }
617 if (mddev->degraded != (mddev->raid_disks>>1)) {
618 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n",
619 mdname(mddev));
620 return ERR_PTR(-EINVAL);
621 }
622
623 /* Set new parameters */
624 mddev->new_level = 0;
625 mddev->new_layout = 0;
626 mddev->new_chunk_sectors = mddev->chunk_sectors;
627 mddev->delta_disks = - mddev->raid_disks / 2;
628 mddev->raid_disks += mddev->delta_disks;
629 mddev->degraded = 0;
630 /* make sure it will be not marked as dirty */
631 mddev->recovery_cp = MaxSector;
632
633 create_strip_zones(mddev, &priv_conf);
634 return priv_conf;
635 }
636
637 static void *raid0_takeover_raid1(struct mddev *mddev)
638 {
639 struct r0conf *priv_conf;
640 int chunksect;
641
642 /* Check layout:
643 * - (N - 1) mirror drives must be already faulty
644 */
645 if ((mddev->raid_disks - 1) != mddev->degraded) {
646 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
647 mdname(mddev));
648 return ERR_PTR(-EINVAL);
649 }
650
651 /*
652 * a raid1 doesn't have the notion of chunk size, so
653 * figure out the largest suitable size we can use.
654 */
655 chunksect = 64 * 2; /* 64K by default */
656
657 /* The array must be an exact multiple of chunksize */
658 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
659 chunksect >>= 1;
660
661 if ((chunksect << 9) < PAGE_SIZE)
662 /* array size does not allow a suitable chunk size */
663 return ERR_PTR(-EINVAL);
664
665 /* Set new parameters */
666 mddev->new_level = 0;
667 mddev->new_layout = 0;
668 mddev->new_chunk_sectors = chunksect;
669 mddev->chunk_sectors = chunksect;
670 mddev->delta_disks = 1 - mddev->raid_disks;
671 mddev->raid_disks = 1;
672 /* make sure it will be not marked as dirty */
673 mddev->recovery_cp = MaxSector;
674
675 create_strip_zones(mddev, &priv_conf);
676 return priv_conf;
677 }
678
679 static void *raid0_takeover(struct mddev *mddev)
680 {
681 /* raid0 can take over:
682 * raid4 - if all data disks are active.
683 * raid5 - providing it is Raid4 layout and one disk is faulty
684 * raid10 - assuming we have all necessary active disks
685 * raid1 - with (N -1) mirror drives faulty
686 */
687
688 if (mddev->bitmap) {
689 printk(KERN_ERR "md/raid0: %s: cannot takeover array with bitmap\n",
690 mdname(mddev));
691 return ERR_PTR(-EBUSY);
692 }
693 if (mddev->level == 4)
694 return raid0_takeover_raid45(mddev);
695
696 if (mddev->level == 5) {
697 if (mddev->layout == ALGORITHM_PARITY_N)
698 return raid0_takeover_raid45(mddev);
699
700 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
701 mdname(mddev), ALGORITHM_PARITY_N);
702 }
703
704 if (mddev->level == 10)
705 return raid0_takeover_raid10(mddev);
706
707 if (mddev->level == 1)
708 return raid0_takeover_raid1(mddev);
709
710 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n",
711 mddev->level);
712
713 return ERR_PTR(-EINVAL);
714 }
715
716 static void raid0_quiesce(struct mddev *mddev, int state)
717 {
718 }
719
720 static struct md_personality raid0_personality=
721 {
722 .name = "raid0",
723 .level = 0,
724 .owner = THIS_MODULE,
725 .make_request = raid0_make_request,
726 .run = raid0_run,
727 .stop = raid0_stop,
728 .status = raid0_status,
729 .size = raid0_size,
730 .takeover = raid0_takeover,
731 .quiesce = raid0_quiesce,
732 };
733
734 static int __init raid0_init (void)
735 {
736 return register_md_personality (&raid0_personality);
737 }
738
739 static void raid0_exit (void)
740 {
741 unregister_md_personality (&raid0_personality);
742 }
743
744 module_init(raid0_init);
745 module_exit(raid0_exit);
746 MODULE_LICENSE("GPL");
747 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
748 MODULE_ALIAS("md-personality-2"); /* RAID0 */
749 MODULE_ALIAS("md-raid0");
750 MODULE_ALIAS("md-level-0");
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