Merge branch 'for-next'
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / md / raid0.c
bloba39f4c355e55046504f99c516d20d4f521f1d453
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
9 RAID-0 management functions.
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.
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.
21 #include <linux/blkdev.h>
22 #include <linux/seq_file.h>
23 #include <linux/slab.h>
24 #include "md.h"
25 #include "raid0.h"
26 #include "raid5.h"
28 static void raid0_unplug(struct request_queue *q)
30 mddev_t *mddev = q->queuedata;
31 raid0_conf_t *conf = mddev->private;
32 mdk_rdev_t **devlist = conf->devlist;
33 int raid_disks = conf->strip_zone[0].nb_dev;
34 int i;
36 for (i=0; i < raid_disks; i++) {
37 struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev);
39 blk_unplug(r_queue);
43 static int raid0_congested(void *data, int bits)
45 mddev_t *mddev = data;
46 raid0_conf_t *conf = mddev->private;
47 mdk_rdev_t **devlist = conf->devlist;
48 int raid_disks = conf->strip_zone[0].nb_dev;
49 int i, ret = 0;
51 if (mddev_congested(mddev, bits))
52 return 1;
54 for (i = 0; i < raid_disks && !ret ; i++) {
55 struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
57 ret |= bdi_congested(&q->backing_dev_info, bits);
59 return ret;
63 * inform the user of the raid configuration
65 static void dump_zones(mddev_t *mddev)
67 int j, k, h;
68 sector_t zone_size = 0;
69 sector_t zone_start = 0;
70 char b[BDEVNAME_SIZE];
71 raid0_conf_t *conf = mddev->private;
72 int raid_disks = conf->strip_zone[0].nb_dev;
73 printk(KERN_INFO "******* %s configuration *********\n",
74 mdname(mddev));
75 h = 0;
76 for (j = 0; j < conf->nr_strip_zones; j++) {
77 printk(KERN_INFO "zone%d=[", j);
78 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
79 printk(KERN_CONT "%s/",
80 bdevname(conf->devlist[j*raid_disks
81 + k]->bdev, b));
82 printk(KERN_CONT "]\n");
84 zone_size = conf->strip_zone[j].zone_end - zone_start;
85 printk(KERN_INFO " zone offset=%llukb "
86 "device offset=%llukb size=%llukb\n",
87 (unsigned long long)zone_start>>1,
88 (unsigned long long)conf->strip_zone[j].dev_start>>1,
89 (unsigned long long)zone_size>>1);
90 zone_start = conf->strip_zone[j].zone_end;
92 printk(KERN_INFO "**********************************\n\n");
95 static int create_strip_zones(mddev_t *mddev, raid0_conf_t **private_conf)
97 int i, c, err;
98 sector_t curr_zone_end, sectors;
99 mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev, **dev;
100 struct strip_zone *zone;
101 int cnt;
102 char b[BDEVNAME_SIZE];
103 raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
105 if (!conf)
106 return -ENOMEM;
107 list_for_each_entry(rdev1, &mddev->disks, same_set) {
108 printk(KERN_INFO "md/raid0:%s: looking at %s\n",
109 mdname(mddev),
110 bdevname(rdev1->bdev, b));
111 c = 0;
113 /* round size to chunk_size */
114 sectors = rdev1->sectors;
115 sector_div(sectors, mddev->chunk_sectors);
116 rdev1->sectors = sectors * mddev->chunk_sectors;
118 list_for_each_entry(rdev2, &mddev->disks, same_set) {
119 printk(KERN_INFO "md/raid0:%s: comparing %s(%llu)",
120 mdname(mddev),
121 bdevname(rdev1->bdev,b),
122 (unsigned long long)rdev1->sectors);
123 printk(KERN_CONT " with %s(%llu)\n",
124 bdevname(rdev2->bdev,b),
125 (unsigned long long)rdev2->sectors);
126 if (rdev2 == rdev1) {
127 printk(KERN_INFO "md/raid0:%s: END\n",
128 mdname(mddev));
129 break;
131 if (rdev2->sectors == rdev1->sectors) {
133 * Not unique, don't count it as a new
134 * group
136 printk(KERN_INFO "md/raid0:%s: EQUAL\n",
137 mdname(mddev));
138 c = 1;
139 break;
141 printk(KERN_INFO "md/raid0:%s: NOT EQUAL\n",
142 mdname(mddev));
144 if (!c) {
145 printk(KERN_INFO "md/raid0:%s: ==> UNIQUE\n",
146 mdname(mddev));
147 conf->nr_strip_zones++;
148 printk(KERN_INFO "md/raid0:%s: %d zones\n",
149 mdname(mddev), conf->nr_strip_zones);
152 printk(KERN_INFO "md/raid0:%s: FINAL %d zones\n",
153 mdname(mddev), conf->nr_strip_zones);
154 err = -ENOMEM;
155 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
156 conf->nr_strip_zones, GFP_KERNEL);
157 if (!conf->strip_zone)
158 goto abort;
159 conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
160 conf->nr_strip_zones*mddev->raid_disks,
161 GFP_KERNEL);
162 if (!conf->devlist)
163 goto abort;
165 /* The first zone must contain all devices, so here we check that
166 * there is a proper alignment of slots to devices and find them all
168 zone = &conf->strip_zone[0];
169 cnt = 0;
170 smallest = NULL;
171 dev = conf->devlist;
172 err = -EINVAL;
173 list_for_each_entry(rdev1, &mddev->disks, same_set) {
174 int j = rdev1->raid_disk;
176 if (mddev->level == 10) {
177 /* taking over a raid10-n2 array */
178 j /= 2;
179 rdev1->new_raid_disk = j;
182 if (j < 0 || j >= mddev->raid_disks) {
183 printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
184 "aborting!\n", mdname(mddev), j);
185 goto abort;
187 if (dev[j]) {
188 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
189 "aborting!\n", mdname(mddev), j);
190 goto abort;
192 dev[j] = rdev1;
194 disk_stack_limits(mddev->gendisk, rdev1->bdev,
195 rdev1->data_offset << 9);
196 /* as we don't honour merge_bvec_fn, we must never risk
197 * violating it, so limit ->max_segments to 1, lying within
198 * a single page.
201 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) {
202 blk_queue_max_segments(mddev->queue, 1);
203 blk_queue_segment_boundary(mddev->queue,
204 PAGE_CACHE_SIZE - 1);
206 if (!smallest || (rdev1->sectors < smallest->sectors))
207 smallest = rdev1;
208 cnt++;
210 if (cnt != mddev->raid_disks) {
211 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - "
212 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks);
213 goto abort;
215 zone->nb_dev = cnt;
216 zone->zone_end = smallest->sectors * cnt;
218 curr_zone_end = zone->zone_end;
220 /* now do the other zones */
221 for (i = 1; i < conf->nr_strip_zones; i++)
223 int j;
225 zone = conf->strip_zone + i;
226 dev = conf->devlist + i * mddev->raid_disks;
228 printk(KERN_INFO "md/raid0:%s: zone %d\n",
229 mdname(mddev), i);
230 zone->dev_start = smallest->sectors;
231 smallest = NULL;
232 c = 0;
234 for (j=0; j<cnt; j++) {
235 rdev = conf->devlist[j];
236 printk(KERN_INFO "md/raid0:%s: checking %s ...",
237 mdname(mddev),
238 bdevname(rdev->bdev, b));
239 if (rdev->sectors <= zone->dev_start) {
240 printk(KERN_CONT " nope.\n");
241 continue;
243 printk(KERN_CONT " contained as device %d\n", c);
244 dev[c] = rdev;
245 c++;
246 if (!smallest || rdev->sectors < smallest->sectors) {
247 smallest = rdev;
248 printk(KERN_INFO "md/raid0:%s: (%llu) is smallest!.\n",
249 mdname(mddev),
250 (unsigned long long)rdev->sectors);
254 zone->nb_dev = c;
255 sectors = (smallest->sectors - zone->dev_start) * c;
256 printk(KERN_INFO "md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
257 mdname(mddev),
258 zone->nb_dev, (unsigned long long)sectors);
260 curr_zone_end += sectors;
261 zone->zone_end = curr_zone_end;
263 printk(KERN_INFO "md/raid0:%s: current zone start: %llu\n",
264 mdname(mddev),
265 (unsigned long long)smallest->sectors);
267 mddev->queue->unplug_fn = raid0_unplug;
268 mddev->queue->backing_dev_info.congested_fn = raid0_congested;
269 mddev->queue->backing_dev_info.congested_data = mddev;
272 * now since we have the hard sector sizes, we can make sure
273 * chunk size is a multiple of that sector size
275 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
276 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
277 mdname(mddev),
278 mddev->chunk_sectors << 9);
279 goto abort;
282 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
283 blk_queue_io_opt(mddev->queue,
284 (mddev->chunk_sectors << 9) * mddev->raid_disks);
286 printk(KERN_INFO "md/raid0:%s: done.\n", mdname(mddev));
287 *private_conf = conf;
289 return 0;
290 abort:
291 kfree(conf->strip_zone);
292 kfree(conf->devlist);
293 kfree(conf);
294 *private_conf = NULL;
295 return err;
299 * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
300 * @q: request queue
301 * @bvm: properties of new bio
302 * @biovec: the request that could be merged to it.
304 * Return amount of bytes we can accept at this offset
306 static int raid0_mergeable_bvec(struct request_queue *q,
307 struct bvec_merge_data *bvm,
308 struct bio_vec *biovec)
310 mddev_t *mddev = q->queuedata;
311 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
312 int max;
313 unsigned int chunk_sectors = mddev->chunk_sectors;
314 unsigned int bio_sectors = bvm->bi_size >> 9;
316 if (is_power_of_2(chunk_sectors))
317 max = (chunk_sectors - ((sector & (chunk_sectors-1))
318 + bio_sectors)) << 9;
319 else
320 max = (chunk_sectors - (sector_div(sector, chunk_sectors)
321 + bio_sectors)) << 9;
322 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
323 if (max <= biovec->bv_len && bio_sectors == 0)
324 return biovec->bv_len;
325 else
326 return max;
329 static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks)
331 sector_t array_sectors = 0;
332 mdk_rdev_t *rdev;
334 WARN_ONCE(sectors || raid_disks,
335 "%s does not support generic reshape\n", __func__);
337 list_for_each_entry(rdev, &mddev->disks, same_set)
338 array_sectors += rdev->sectors;
340 return array_sectors;
343 static int raid0_run(mddev_t *mddev)
345 raid0_conf_t *conf;
346 int ret;
348 if (mddev->chunk_sectors == 0) {
349 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
350 mdname(mddev));
351 return -EINVAL;
353 if (md_check_no_bitmap(mddev))
354 return -EINVAL;
355 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
356 mddev->queue->queue_lock = &mddev->queue->__queue_lock;
358 /* if private is not null, we are here after takeover */
359 if (mddev->private == NULL) {
360 ret = create_strip_zones(mddev, &conf);
361 if (ret < 0)
362 return ret;
363 mddev->private = conf;
365 conf = mddev->private;
367 /* calculate array device size */
368 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
370 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
371 mdname(mddev),
372 (unsigned long long)mddev->array_sectors);
373 /* calculate the max read-ahead size.
374 * For read-ahead of large files to be effective, we need to
375 * readahead at least twice a whole stripe. i.e. number of devices
376 * multiplied by chunk size times 2.
377 * If an individual device has an ra_pages greater than the
378 * chunk size, then we will not drive that device as hard as it
379 * wants. We consider this a configuration error: a larger
380 * chunksize should be used in that case.
383 int stripe = mddev->raid_disks *
384 (mddev->chunk_sectors << 9) / PAGE_SIZE;
385 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
386 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
389 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
390 dump_zones(mddev);
391 md_integrity_register(mddev);
392 return 0;
395 static int raid0_stop(mddev_t *mddev)
397 raid0_conf_t *conf = mddev->private;
399 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
400 kfree(conf->strip_zone);
401 kfree(conf->devlist);
402 kfree(conf);
403 mddev->private = NULL;
404 return 0;
407 /* Find the zone which holds a particular offset
408 * Update *sectorp to be an offset in that zone
410 static struct strip_zone *find_zone(struct raid0_private_data *conf,
411 sector_t *sectorp)
413 int i;
414 struct strip_zone *z = conf->strip_zone;
415 sector_t sector = *sectorp;
417 for (i = 0; i < conf->nr_strip_zones; i++)
418 if (sector < z[i].zone_end) {
419 if (i)
420 *sectorp = sector - z[i-1].zone_end;
421 return z + i;
423 BUG();
427 * remaps the bio to the target device. we separate two flows.
428 * power 2 flow and a general flow for the sake of perfromance
430 static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone,
431 sector_t sector, sector_t *sector_offset)
433 unsigned int sect_in_chunk;
434 sector_t chunk;
435 raid0_conf_t *conf = mddev->private;
436 int raid_disks = conf->strip_zone[0].nb_dev;
437 unsigned int chunk_sects = mddev->chunk_sectors;
439 if (is_power_of_2(chunk_sects)) {
440 int chunksect_bits = ffz(~chunk_sects);
441 /* find the sector offset inside the chunk */
442 sect_in_chunk = sector & (chunk_sects - 1);
443 sector >>= chunksect_bits;
444 /* chunk in zone */
445 chunk = *sector_offset;
446 /* quotient is the chunk in real device*/
447 sector_div(chunk, zone->nb_dev << chunksect_bits);
448 } else{
449 sect_in_chunk = sector_div(sector, chunk_sects);
450 chunk = *sector_offset;
451 sector_div(chunk, chunk_sects * zone->nb_dev);
454 * position the bio over the real device
455 * real sector = chunk in device + starting of zone
456 * + the position in the chunk
458 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
459 return conf->devlist[(zone - conf->strip_zone)*raid_disks
460 + sector_div(sector, zone->nb_dev)];
464 * Is io distribute over 1 or more chunks ?
466 static inline int is_io_in_chunk_boundary(mddev_t *mddev,
467 unsigned int chunk_sects, struct bio *bio)
469 if (likely(is_power_of_2(chunk_sects))) {
470 return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
471 + (bio->bi_size >> 9));
472 } else{
473 sector_t sector = bio->bi_sector;
474 return chunk_sects >= (sector_div(sector, chunk_sects)
475 + (bio->bi_size >> 9));
479 static int raid0_make_request(mddev_t *mddev, struct bio *bio)
481 unsigned int chunk_sects;
482 sector_t sector_offset;
483 struct strip_zone *zone;
484 mdk_rdev_t *tmp_dev;
486 if (unlikely(bio->bi_rw & REQ_FLUSH)) {
487 md_flush_request(mddev, bio);
488 return 0;
491 chunk_sects = mddev->chunk_sectors;
492 if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) {
493 sector_t sector = bio->bi_sector;
494 struct bio_pair *bp;
495 /* Sanity check -- queue functions should prevent this happening */
496 if (bio->bi_vcnt != 1 ||
497 bio->bi_idx != 0)
498 goto bad_map;
499 /* This is a one page bio that upper layers
500 * refuse to split for us, so we need to split it.
502 if (likely(is_power_of_2(chunk_sects)))
503 bp = bio_split(bio, chunk_sects - (sector &
504 (chunk_sects-1)));
505 else
506 bp = bio_split(bio, chunk_sects -
507 sector_div(sector, chunk_sects));
508 if (raid0_make_request(mddev, &bp->bio1))
509 generic_make_request(&bp->bio1);
510 if (raid0_make_request(mddev, &bp->bio2))
511 generic_make_request(&bp->bio2);
513 bio_pair_release(bp);
514 return 0;
517 sector_offset = bio->bi_sector;
518 zone = find_zone(mddev->private, &sector_offset);
519 tmp_dev = map_sector(mddev, zone, bio->bi_sector,
520 &sector_offset);
521 bio->bi_bdev = tmp_dev->bdev;
522 bio->bi_sector = sector_offset + zone->dev_start +
523 tmp_dev->data_offset;
525 * Let the main block layer submit the IO and resolve recursion:
527 return 1;
529 bad_map:
530 printk("md/raid0:%s: make_request bug: can't convert block across chunks"
531 " or bigger than %dk %llu %d\n",
532 mdname(mddev), chunk_sects / 2,
533 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
535 bio_io_error(bio);
536 return 0;
539 static void raid0_status(struct seq_file *seq, mddev_t *mddev)
541 #undef MD_DEBUG
542 #ifdef MD_DEBUG
543 int j, k, h;
544 char b[BDEVNAME_SIZE];
545 raid0_conf_t *conf = mddev->private;
546 int raid_disks = conf->strip_zone[0].nb_dev;
548 sector_t zone_size;
549 sector_t zone_start = 0;
550 h = 0;
552 for (j = 0; j < conf->nr_strip_zones; j++) {
553 seq_printf(seq, " z%d", j);
554 seq_printf(seq, "=[");
555 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
556 seq_printf(seq, "%s/", bdevname(
557 conf->devlist[j*raid_disks + k]
558 ->bdev, b));
560 zone_size = conf->strip_zone[j].zone_end - zone_start;
561 seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n",
562 (unsigned long long)zone_start>>1,
563 (unsigned long long)conf->strip_zone[j].dev_start>>1,
564 (unsigned long long)zone_size>>1);
565 zone_start = conf->strip_zone[j].zone_end;
567 #endif
568 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
569 return;
572 static void *raid0_takeover_raid45(mddev_t *mddev)
574 mdk_rdev_t *rdev;
575 raid0_conf_t *priv_conf;
577 if (mddev->degraded != 1) {
578 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
579 mdname(mddev),
580 mddev->degraded);
581 return ERR_PTR(-EINVAL);
584 list_for_each_entry(rdev, &mddev->disks, same_set) {
585 /* check slot number for a disk */
586 if (rdev->raid_disk == mddev->raid_disks-1) {
587 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
588 mdname(mddev));
589 return ERR_PTR(-EINVAL);
593 /* Set new parameters */
594 mddev->new_level = 0;
595 mddev->new_layout = 0;
596 mddev->new_chunk_sectors = mddev->chunk_sectors;
597 mddev->raid_disks--;
598 mddev->delta_disks = -1;
599 /* make sure it will be not marked as dirty */
600 mddev->recovery_cp = MaxSector;
602 create_strip_zones(mddev, &priv_conf);
603 return priv_conf;
606 static void *raid0_takeover_raid10(mddev_t *mddev)
608 raid0_conf_t *priv_conf;
610 /* Check layout:
611 * - far_copies must be 1
612 * - near_copies must be 2
613 * - disks number must be even
614 * - all mirrors must be already degraded
616 if (mddev->layout != ((1 << 8) + 2)) {
617 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n",
618 mdname(mddev),
619 mddev->layout);
620 return ERR_PTR(-EINVAL);
622 if (mddev->raid_disks & 1) {
623 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n",
624 mdname(mddev));
625 return ERR_PTR(-EINVAL);
627 if (mddev->degraded != (mddev->raid_disks>>1)) {
628 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n",
629 mdname(mddev));
630 return ERR_PTR(-EINVAL);
633 /* Set new parameters */
634 mddev->new_level = 0;
635 mddev->new_layout = 0;
636 mddev->new_chunk_sectors = mddev->chunk_sectors;
637 mddev->delta_disks = - mddev->raid_disks / 2;
638 mddev->raid_disks += mddev->delta_disks;
639 mddev->degraded = 0;
640 /* make sure it will be not marked as dirty */
641 mddev->recovery_cp = MaxSector;
643 create_strip_zones(mddev, &priv_conf);
644 return priv_conf;
647 static void *raid0_takeover(mddev_t *mddev)
649 /* raid0 can take over:
650 * raid4 - if all data disks are active.
651 * raid5 - providing it is Raid4 layout and one disk is faulty
652 * raid10 - assuming we have all necessary active disks
654 if (mddev->level == 4)
655 return raid0_takeover_raid45(mddev);
657 if (mddev->level == 5) {
658 if (mddev->layout == ALGORITHM_PARITY_N)
659 return raid0_takeover_raid45(mddev);
661 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
662 mdname(mddev), ALGORITHM_PARITY_N);
665 if (mddev->level == 10)
666 return raid0_takeover_raid10(mddev);
668 return ERR_PTR(-EINVAL);
671 static void raid0_quiesce(mddev_t *mddev, int state)
675 static struct mdk_personality raid0_personality=
677 .name = "raid0",
678 .level = 0,
679 .owner = THIS_MODULE,
680 .make_request = raid0_make_request,
681 .run = raid0_run,
682 .stop = raid0_stop,
683 .status = raid0_status,
684 .size = raid0_size,
685 .takeover = raid0_takeover,
686 .quiesce = raid0_quiesce,
689 static int __init raid0_init (void)
691 return register_md_personality (&raid0_personality);
694 static void raid0_exit (void)
696 unregister_md_personality (&raid0_personality);
699 module_init(raid0_init);
700 module_exit(raid0_exit);
701 MODULE_LICENSE("GPL");
702 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
703 MODULE_ALIAS("md-personality-2"); /* RAID0 */
704 MODULE_ALIAS("md-raid0");
705 MODULE_ALIAS("md-level-0");