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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/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"
27
28static int raid0_congested(void *data, int bits)
29{
30 mddev_t *mddev = data;
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, 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*/
50static void dump_zones(mddev_t *mddev)
51{
52 int j, k, h;
53 sector_t zone_size = 0;
54 sector_t zone_start = 0;
55 char b[BDEVNAME_SIZE];
56 raid0_conf_t *conf = mddev->private;
57 int raid_disks = conf->strip_zone[0].nb_dev;
58 printk(KERN_INFO "******* %s configuration *********\n",
59 mdname(mddev));
60 h = 0;
61 for (j = 0; j < conf->nr_strip_zones; j++) {
62 printk(KERN_INFO "zone%d=[", j);
63 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
64 printk(KERN_CONT "%s/",
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=%llukb "
71 "device offset=%llukb size=%llukb\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\n");
78}
79
80static int create_strip_zones(mddev_t *mddev, raid0_conf_t **private_conf)
81{
82 int i, c, err;
83 sector_t curr_zone_end, sectors;
84 mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev, **dev;
85 struct strip_zone *zone;
86 int cnt;
87 char b[BDEVNAME_SIZE];
88 raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
89
90 if (!conf)
91 return -ENOMEM;
92 list_for_each_entry(rdev1, &mddev->disks, same_set) {
93 printk(KERN_INFO "md/raid0:%s: looking at %s\n",
94 mdname(mddev),
95 bdevname(rdev1->bdev, b));
96 c = 0;
97
98 /* round size to chunk_size */
99 sectors = rdev1->sectors;
100 sector_div(sectors, mddev->chunk_sectors);
101 rdev1->sectors = sectors * mddev->chunk_sectors;
102
103 list_for_each_entry(rdev2, &mddev->disks, same_set) {
104 printk(KERN_INFO "md/raid0:%s: comparing %s(%llu)",
105 mdname(mddev),
106 bdevname(rdev1->bdev,b),
107 (unsigned long long)rdev1->sectors);
108 printk(KERN_CONT " with %s(%llu)\n",
109 bdevname(rdev2->bdev,b),
110 (unsigned long long)rdev2->sectors);
111 if (rdev2 == rdev1) {
112 printk(KERN_INFO "md/raid0:%s: END\n",
113 mdname(mddev));
114 break;
115 }
116 if (rdev2->sectors == rdev1->sectors) {
117 /*
118 * Not unique, don't count it as a new
119 * group
120 */
121 printk(KERN_INFO "md/raid0:%s: EQUAL\n",
122 mdname(mddev));
123 c = 1;
124 break;
125 }
126 printk(KERN_INFO "md/raid0:%s: NOT EQUAL\n",
127 mdname(mddev));
128 }
129 if (!c) {
130 printk(KERN_INFO "md/raid0:%s: ==> UNIQUE\n",
131 mdname(mddev));
132 conf->nr_strip_zones++;
133 printk(KERN_INFO "md/raid0:%s: %d zones\n",
134 mdname(mddev), conf->nr_strip_zones);
135 }
136 }
137 printk(KERN_INFO "md/raid0:%s: FINAL %d zones\n",
138 mdname(mddev), conf->nr_strip_zones);
139 err = -ENOMEM;
140 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
141 conf->nr_strip_zones, GFP_KERNEL);
142 if (!conf->strip_zone)
143 goto abort;
144 conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
145 conf->nr_strip_zones*mddev->raid_disks,
146 GFP_KERNEL);
147 if (!conf->devlist)
148 goto abort;
149
150 /* The first zone must contain all devices, so here we check that
151 * there is a proper alignment of slots to devices and find them all
152 */
153 zone = &conf->strip_zone[0];
154 cnt = 0;
155 smallest = NULL;
156 dev = conf->devlist;
157 err = -EINVAL;
158 list_for_each_entry(rdev1, &mddev->disks, same_set) {
159 int j = rdev1->raid_disk;
160
161 if (mddev->level == 10) {
162 /* taking over a raid10-n2 array */
163 j /= 2;
164 rdev1->new_raid_disk = j;
165 }
166
167 if (mddev->level == 1) {
168 /* taiking over a raid1 array-
169 * we have only one active disk
170 */
171 j = 0;
172 rdev1->new_raid_disk = j;
173 }
174
175 if (j < 0 || j >= mddev->raid_disks) {
176 printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
177 "aborting!\n", mdname(mddev), j);
178 goto abort;
179 }
180 if (dev[j]) {
181 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
182 "aborting!\n", mdname(mddev), j);
183 goto abort;
184 }
185 dev[j] = rdev1;
186
187 disk_stack_limits(mddev->gendisk, rdev1->bdev,
188 rdev1->data_offset << 9);
189 /* as we don't honour merge_bvec_fn, we must never risk
190 * violating it, so limit ->max_segments to 1, lying within
191 * a single page.
192 */
193
194 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) {
195 blk_queue_max_segments(mddev->queue, 1);
196 blk_queue_segment_boundary(mddev->queue,
197 PAGE_CACHE_SIZE - 1);
198 }
199 if (!smallest || (rdev1->sectors < smallest->sectors))
200 smallest = rdev1;
201 cnt++;
202 }
203 if (cnt != mddev->raid_disks) {
204 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - "
205 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks);
206 goto abort;
207 }
208 zone->nb_dev = cnt;
209 zone->zone_end = smallest->sectors * cnt;
210
211 curr_zone_end = zone->zone_end;
212
213 /* now do the other zones */
214 for (i = 1; i < conf->nr_strip_zones; i++)
215 {
216 int j;
217
218 zone = conf->strip_zone + i;
219 dev = conf->devlist + i * mddev->raid_disks;
220
221 printk(KERN_INFO "md/raid0:%s: zone %d\n",
222 mdname(mddev), i);
223 zone->dev_start = smallest->sectors;
224 smallest = NULL;
225 c = 0;
226
227 for (j=0; j<cnt; j++) {
228 rdev = conf->devlist[j];
229 printk(KERN_INFO "md/raid0:%s: checking %s ...",
230 mdname(mddev),
231 bdevname(rdev->bdev, b));
232 if (rdev->sectors <= zone->dev_start) {
233 printk(KERN_CONT " nope.\n");
234 continue;
235 }
236 printk(KERN_CONT " contained as device %d\n", c);
237 dev[c] = rdev;
238 c++;
239 if (!smallest || rdev->sectors < smallest->sectors) {
240 smallest = rdev;
241 printk(KERN_INFO "md/raid0:%s: (%llu) is smallest!.\n",
242 mdname(mddev),
243 (unsigned long long)rdev->sectors);
244 }
245 }
246
247 zone->nb_dev = c;
248 sectors = (smallest->sectors - zone->dev_start) * c;
249 printk(KERN_INFO "md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
250 mdname(mddev),
251 zone->nb_dev, (unsigned long long)sectors);
252
253 curr_zone_end += sectors;
254 zone->zone_end = curr_zone_end;
255
256 printk(KERN_INFO "md/raid0:%s: current zone start: %llu\n",
257 mdname(mddev),
258 (unsigned long long)smallest->sectors);
259 }
260 mddev->queue->backing_dev_info.congested_fn = raid0_congested;
261 mddev->queue->backing_dev_info.congested_data = mddev;
262
263 /*
264 * now since we have the hard sector sizes, we can make sure
265 * chunk size is a multiple of that sector size
266 */
267 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
268 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
269 mdname(mddev),
270 mddev->chunk_sectors << 9);
271 goto abort;
272 }
273
274 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
275 blk_queue_io_opt(mddev->queue,
276 (mddev->chunk_sectors << 9) * mddev->raid_disks);
277
278 printk(KERN_INFO "md/raid0:%s: done.\n", mdname(mddev));
279 *private_conf = conf;
280
281 return 0;
282abort:
283 kfree(conf->strip_zone);
284 kfree(conf->devlist);
285 kfree(conf);
286 *private_conf = NULL;
287 return err;
288}
289
290/**
291 * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
292 * @q: request queue
293 * @bvm: properties of new bio
294 * @biovec: the request that could be merged to it.
295 *
296 * Return amount of bytes we can accept at this offset
297 */
298static int raid0_mergeable_bvec(struct request_queue *q,
299 struct bvec_merge_data *bvm,
300 struct bio_vec *biovec)
301{
302 mddev_t *mddev = q->queuedata;
303 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
304 int max;
305 unsigned int chunk_sectors = mddev->chunk_sectors;
306 unsigned int bio_sectors = bvm->bi_size >> 9;
307
308 if (is_power_of_2(chunk_sectors))
309 max = (chunk_sectors - ((sector & (chunk_sectors-1))
310 + bio_sectors)) << 9;
311 else
312 max = (chunk_sectors - (sector_div(sector, chunk_sectors)
313 + bio_sectors)) << 9;
314 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
315 if (max <= biovec->bv_len && bio_sectors == 0)
316 return biovec->bv_len;
317 else
318 return max;
319}
320
321static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks)
322{
323 sector_t array_sectors = 0;
324 mdk_rdev_t *rdev;
325
326 WARN_ONCE(sectors || raid_disks,
327 "%s does not support generic reshape\n", __func__);
328
329 list_for_each_entry(rdev, &mddev->disks, same_set)
330 array_sectors += rdev->sectors;
331
332 return array_sectors;
333}
334
335static int raid0_run(mddev_t *mddev)
336{
337 raid0_conf_t *conf;
338 int ret;
339
340 if (mddev->chunk_sectors == 0) {
341 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
342 mdname(mddev));
343 return -EINVAL;
344 }
345 if (md_check_no_bitmap(mddev))
346 return -EINVAL;
347 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
348
349 /* if private is not null, we are here after takeover */
350 if (mddev->private == NULL) {
351 ret = create_strip_zones(mddev, &conf);
352 if (ret < 0)
353 return ret;
354 mddev->private = conf;
355 }
356 conf = mddev->private;
357
358 /* calculate array device size */
359 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
360
361 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
362 mdname(mddev),
363 (unsigned long long)mddev->array_sectors);
364 /* calculate the max read-ahead size.
365 * For read-ahead of large files to be effective, we need to
366 * readahead at least twice a whole stripe. i.e. number of devices
367 * multiplied by chunk size times 2.
368 * If an individual device has an ra_pages greater than the
369 * chunk size, then we will not drive that device as hard as it
370 * wants. We consider this a configuration error: a larger
371 * chunksize should be used in that case.
372 */
373 {
374 int stripe = mddev->raid_disks *
375 (mddev->chunk_sectors << 9) / PAGE_SIZE;
376 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
377 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
378 }
379
380 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
381 dump_zones(mddev);
382 return md_integrity_register(mddev);
383}
384
385static int raid0_stop(mddev_t *mddev)
386{
387 raid0_conf_t *conf = mddev->private;
388
389 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
390 kfree(conf->strip_zone);
391 kfree(conf->devlist);
392 kfree(conf);
393 mddev->private = NULL;
394 return 0;
395}
396
397/* Find the zone which holds a particular offset
398 * Update *sectorp to be an offset in that zone
399 */
400static struct strip_zone *find_zone(struct raid0_private_data *conf,
401 sector_t *sectorp)
402{
403 int i;
404 struct strip_zone *z = conf->strip_zone;
405 sector_t sector = *sectorp;
406
407 for (i = 0; i < conf->nr_strip_zones; i++)
408 if (sector < z[i].zone_end) {
409 if (i)
410 *sectorp = sector - z[i-1].zone_end;
411 return z + i;
412 }
413 BUG();
414}
415
416/*
417 * remaps the bio to the target device. we separate two flows.
418 * power 2 flow and a general flow for the sake of perfromance
419*/
420static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone,
421 sector_t sector, sector_t *sector_offset)
422{
423 unsigned int sect_in_chunk;
424 sector_t chunk;
425 raid0_conf_t *conf = mddev->private;
426 int raid_disks = conf->strip_zone[0].nb_dev;
427 unsigned int chunk_sects = mddev->chunk_sectors;
428
429 if (is_power_of_2(chunk_sects)) {
430 int chunksect_bits = ffz(~chunk_sects);
431 /* find the sector offset inside the chunk */
432 sect_in_chunk = sector & (chunk_sects - 1);
433 sector >>= chunksect_bits;
434 /* chunk in zone */
435 chunk = *sector_offset;
436 /* quotient is the chunk in real device*/
437 sector_div(chunk, zone->nb_dev << chunksect_bits);
438 } else{
439 sect_in_chunk = sector_div(sector, chunk_sects);
440 chunk = *sector_offset;
441 sector_div(chunk, chunk_sects * zone->nb_dev);
442 }
443 /*
444 * position the bio over the real device
445 * real sector = chunk in device + starting of zone
446 * + the position in the chunk
447 */
448 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
449 return conf->devlist[(zone - conf->strip_zone)*raid_disks
450 + sector_div(sector, zone->nb_dev)];
451}
452
453/*
454 * Is io distribute over 1 or more chunks ?
455*/
456static inline int is_io_in_chunk_boundary(mddev_t *mddev,
457 unsigned int chunk_sects, struct bio *bio)
458{
459 if (likely(is_power_of_2(chunk_sects))) {
460 return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
461 + (bio->bi_size >> 9));
462 } else{
463 sector_t sector = bio->bi_sector;
464 return chunk_sects >= (sector_div(sector, chunk_sects)
465 + (bio->bi_size >> 9));
466 }
467}
468
469static int raid0_make_request(mddev_t *mddev, struct bio *bio)
470{
471 unsigned int chunk_sects;
472 sector_t sector_offset;
473 struct strip_zone *zone;
474 mdk_rdev_t *tmp_dev;
475
476 if (unlikely(bio->bi_rw & REQ_FLUSH)) {
477 md_flush_request(mddev, bio);
478 return 0;
479 }
480
481 chunk_sects = mddev->chunk_sectors;
482 if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) {
483 sector_t sector = bio->bi_sector;
484 struct bio_pair *bp;
485 /* Sanity check -- queue functions should prevent this happening */
486 if (bio->bi_vcnt != 1 ||
487 bio->bi_idx != 0)
488 goto bad_map;
489 /* This is a one page bio that upper layers
490 * refuse to split for us, so we need to split it.
491 */
492 if (likely(is_power_of_2(chunk_sects)))
493 bp = bio_split(bio, chunk_sects - (sector &
494 (chunk_sects-1)));
495 else
496 bp = bio_split(bio, chunk_sects -
497 sector_div(sector, chunk_sects));
498 if (raid0_make_request(mddev, &bp->bio1))
499 generic_make_request(&bp->bio1);
500 if (raid0_make_request(mddev, &bp->bio2))
501 generic_make_request(&bp->bio2);
502
503 bio_pair_release(bp);
504 return 0;
505 }
506
507 sector_offset = bio->bi_sector;
508 zone = find_zone(mddev->private, §or_offset);
509 tmp_dev = map_sector(mddev, zone, bio->bi_sector,
510 §or_offset);
511 bio->bi_bdev = tmp_dev->bdev;
512 bio->bi_sector = sector_offset + zone->dev_start +
513 tmp_dev->data_offset;
514 /*
515 * Let the main block layer submit the IO and resolve recursion:
516 */
517 return 1;
518
519bad_map:
520 printk("md/raid0:%s: make_request bug: can't convert block across chunks"
521 " or bigger than %dk %llu %d\n",
522 mdname(mddev), chunk_sects / 2,
523 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
524
525 bio_io_error(bio);
526 return 0;
527}
528
529static void raid0_status(struct seq_file *seq, mddev_t *mddev)
530{
531#undef MD_DEBUG
532#ifdef MD_DEBUG
533 int j, k, h;
534 char b[BDEVNAME_SIZE];
535 raid0_conf_t *conf = mddev->private;
536 int raid_disks = conf->strip_zone[0].nb_dev;
537
538 sector_t zone_size;
539 sector_t zone_start = 0;
540 h = 0;
541
542 for (j = 0; j < conf->nr_strip_zones; j++) {
543 seq_printf(seq, " z%d", j);
544 seq_printf(seq, "=[");
545 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
546 seq_printf(seq, "%s/", bdevname(
547 conf->devlist[j*raid_disks + k]
548 ->bdev, b));
549
550 zone_size = conf->strip_zone[j].zone_end - zone_start;
551 seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n",
552 (unsigned long long)zone_start>>1,
553 (unsigned long long)conf->strip_zone[j].dev_start>>1,
554 (unsigned long long)zone_size>>1);
555 zone_start = conf->strip_zone[j].zone_end;
556 }
557#endif
558 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
559 return;
560}
561
562static void *raid0_takeover_raid45(mddev_t *mddev)
563{
564 mdk_rdev_t *rdev;
565 raid0_conf_t *priv_conf;
566
567 if (mddev->degraded != 1) {
568 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
569 mdname(mddev),
570 mddev->degraded);
571 return ERR_PTR(-EINVAL);
572 }
573
574 list_for_each_entry(rdev, &mddev->disks, same_set) {
575 /* check slot number for a disk */
576 if (rdev->raid_disk == mddev->raid_disks-1) {
577 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
578 mdname(mddev));
579 return ERR_PTR(-EINVAL);
580 }
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
596static void *raid0_takeover_raid10(mddev_t *mddev)
597{
598 raid0_conf_t *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
637static void *raid0_takeover_raid1(mddev_t *mddev)
638{
639 raid0_conf_t *priv_conf;
640
641 /* Check layout:
642 * - (N - 1) mirror drives must be already faulty
643 */
644 if ((mddev->raid_disks - 1) != mddev->degraded) {
645 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
646 mdname(mddev));
647 return ERR_PTR(-EINVAL);
648 }
649
650 /* Set new parameters */
651 mddev->new_level = 0;
652 mddev->new_layout = 0;
653 mddev->new_chunk_sectors = 128; /* by default set chunk size to 64k */
654 mddev->delta_disks = 1 - mddev->raid_disks;
655 mddev->raid_disks = 1;
656 /* make sure it will be not marked as dirty */
657 mddev->recovery_cp = MaxSector;
658
659 create_strip_zones(mddev, &priv_conf);
660 return priv_conf;
661}
662
663static void *raid0_takeover(mddev_t *mddev)
664{
665 /* raid0 can take over:
666 * raid4 - if all data disks are active.
667 * raid5 - providing it is Raid4 layout and one disk is faulty
668 * raid10 - assuming we have all necessary active disks
669 * raid1 - with (N -1) mirror drives faulty
670 */
671 if (mddev->level == 4)
672 return raid0_takeover_raid45(mddev);
673
674 if (mddev->level == 5) {
675 if (mddev->layout == ALGORITHM_PARITY_N)
676 return raid0_takeover_raid45(mddev);
677
678 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
679 mdname(mddev), ALGORITHM_PARITY_N);
680 }
681
682 if (mddev->level == 10)
683 return raid0_takeover_raid10(mddev);
684
685 if (mddev->level == 1)
686 return raid0_takeover_raid1(mddev);
687
688 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n",
689 mddev->level);
690
691 return ERR_PTR(-EINVAL);
692}
693
694static void raid0_quiesce(mddev_t *mddev, int state)
695{
696}
697
698static struct mdk_personality raid0_personality=
699{
700 .name = "raid0",
701 .level = 0,
702 .owner = THIS_MODULE,
703 .make_request = raid0_make_request,
704 .run = raid0_run,
705 .stop = raid0_stop,
706 .status = raid0_status,
707 .size = raid0_size,
708 .takeover = raid0_takeover,
709 .quiesce = raid0_quiesce,
710};
711
712static int __init raid0_init (void)
713{
714 return register_md_personality (&raid0_personality);
715}
716
717static void raid0_exit (void)
718{
719 unregister_md_personality (&raid0_personality);
720}
721
722module_init(raid0_init);
723module_exit(raid0_exit);
724MODULE_LICENSE("GPL");
725MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
726MODULE_ALIAS("md-personality-2"); /* RAID0 */
727MODULE_ALIAS("md-raid0");
728MODULE_ALIAS("md-level-0");
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 <trace/events/block.h>
25#include "md.h"
26#include "raid0.h"
27#include "raid5.h"
28
29#define UNSUPPORTED_MDDEV_FLAGS \
30 ((1L << MD_HAS_JOURNAL) | \
31 (1L << MD_JOURNAL_CLEAN) | \
32 (1L << MD_FAILFAST_SUPPORTED))
33
34static int raid0_congested(struct mddev *mddev, int bits)
35{
36 struct r0conf *conf = mddev->private;
37 struct md_rdev **devlist = conf->devlist;
38 int raid_disks = conf->strip_zone[0].nb_dev;
39 int i, ret = 0;
40
41 for (i = 0; i < raid_disks && !ret ; i++) {
42 struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
43
44 ret |= bdi_congested(&q->backing_dev_info, bits);
45 }
46 return ret;
47}
48
49/*
50 * inform the user of the raid configuration
51*/
52static void dump_zones(struct mddev *mddev)
53{
54 int j, k;
55 sector_t zone_size = 0;
56 sector_t zone_start = 0;
57 char b[BDEVNAME_SIZE];
58 struct r0conf *conf = mddev->private;
59 int raid_disks = conf->strip_zone[0].nb_dev;
60 pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
61 mdname(mddev),
62 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
63 for (j = 0; j < conf->nr_strip_zones; j++) {
64 char line[200];
65 int len = 0;
66
67 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
68 len += snprintf(line+len, 200-len, "%s%s", k?"/":"",
69 bdevname(conf->devlist[j*raid_disks
70 + k]->bdev, b));
71 pr_debug("md: zone%d=[%s]\n", j, line);
72
73 zone_size = conf->strip_zone[j].zone_end - zone_start;
74 pr_debug(" zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n",
75 (unsigned long long)zone_start>>1,
76 (unsigned long long)conf->strip_zone[j].dev_start>>1,
77 (unsigned long long)zone_size>>1);
78 zone_start = conf->strip_zone[j].zone_end;
79 }
80}
81
82static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
83{
84 int i, c, err;
85 sector_t curr_zone_end, sectors;
86 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
87 struct strip_zone *zone;
88 int cnt;
89 char b[BDEVNAME_SIZE];
90 char b2[BDEVNAME_SIZE];
91 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
92 unsigned short blksize = 512;
93
94 *private_conf = ERR_PTR(-ENOMEM);
95 if (!conf)
96 return -ENOMEM;
97 rdev_for_each(rdev1, mddev) {
98 pr_debug("md/raid0:%s: looking at %s\n",
99 mdname(mddev),
100 bdevname(rdev1->bdev, b));
101 c = 0;
102
103 /* round size to chunk_size */
104 sectors = rdev1->sectors;
105 sector_div(sectors, mddev->chunk_sectors);
106 rdev1->sectors = sectors * mddev->chunk_sectors;
107
108 blksize = max(blksize, queue_logical_block_size(
109 rdev1->bdev->bd_disk->queue));
110
111 rdev_for_each(rdev2, mddev) {
112 pr_debug("md/raid0:%s: comparing %s(%llu)"
113 " with %s(%llu)\n",
114 mdname(mddev),
115 bdevname(rdev1->bdev,b),
116 (unsigned long long)rdev1->sectors,
117 bdevname(rdev2->bdev,b2),
118 (unsigned long long)rdev2->sectors);
119 if (rdev2 == rdev1) {
120 pr_debug("md/raid0:%s: END\n",
121 mdname(mddev));
122 break;
123 }
124 if (rdev2->sectors == rdev1->sectors) {
125 /*
126 * Not unique, don't count it as a new
127 * group
128 */
129 pr_debug("md/raid0:%s: EQUAL\n",
130 mdname(mddev));
131 c = 1;
132 break;
133 }
134 pr_debug("md/raid0:%s: NOT EQUAL\n",
135 mdname(mddev));
136 }
137 if (!c) {
138 pr_debug("md/raid0:%s: ==> UNIQUE\n",
139 mdname(mddev));
140 conf->nr_strip_zones++;
141 pr_debug("md/raid0:%s: %d zones\n",
142 mdname(mddev), conf->nr_strip_zones);
143 }
144 }
145 pr_debug("md/raid0:%s: FINAL %d zones\n",
146 mdname(mddev), conf->nr_strip_zones);
147 /*
148 * now since we have the hard sector sizes, we can make sure
149 * chunk size is a multiple of that sector size
150 */
151 if ((mddev->chunk_sectors << 9) % blksize) {
152 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
153 mdname(mddev),
154 mddev->chunk_sectors << 9, blksize);
155 err = -EINVAL;
156 goto abort;
157 }
158
159 err = -ENOMEM;
160 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
161 conf->nr_strip_zones, GFP_KERNEL);
162 if (!conf->strip_zone)
163 goto abort;
164 conf->devlist = kzalloc(sizeof(struct md_rdev*)*
165 conf->nr_strip_zones*mddev->raid_disks,
166 GFP_KERNEL);
167 if (!conf->devlist)
168 goto abort;
169
170 /* The first zone must contain all devices, so here we check that
171 * there is a proper alignment of slots to devices and find them all
172 */
173 zone = &conf->strip_zone[0];
174 cnt = 0;
175 smallest = NULL;
176 dev = conf->devlist;
177 err = -EINVAL;
178 rdev_for_each(rdev1, mddev) {
179 int j = rdev1->raid_disk;
180
181 if (mddev->level == 10) {
182 /* taking over a raid10-n2 array */
183 j /= 2;
184 rdev1->new_raid_disk = j;
185 }
186
187 if (mddev->level == 1) {
188 /* taiking over a raid1 array-
189 * we have only one active disk
190 */
191 j = 0;
192 rdev1->new_raid_disk = j;
193 }
194
195 if (j < 0) {
196 pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
197 mdname(mddev));
198 goto abort;
199 }
200 if (j >= mddev->raid_disks) {
201 pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
202 mdname(mddev), j);
203 goto abort;
204 }
205 if (dev[j]) {
206 pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
207 mdname(mddev), j);
208 goto abort;
209 }
210 dev[j] = rdev1;
211
212 if (!smallest || (rdev1->sectors < smallest->sectors))
213 smallest = rdev1;
214 cnt++;
215 }
216 if (cnt != mddev->raid_disks) {
217 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
218 mdname(mddev), cnt, mddev->raid_disks);
219 goto abort;
220 }
221 zone->nb_dev = cnt;
222 zone->zone_end = smallest->sectors * cnt;
223
224 curr_zone_end = zone->zone_end;
225
226 /* now do the other zones */
227 for (i = 1; i < conf->nr_strip_zones; i++)
228 {
229 int j;
230
231 zone = conf->strip_zone + i;
232 dev = conf->devlist + i * mddev->raid_disks;
233
234 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
235 zone->dev_start = smallest->sectors;
236 smallest = NULL;
237 c = 0;
238
239 for (j=0; j<cnt; j++) {
240 rdev = conf->devlist[j];
241 if (rdev->sectors <= zone->dev_start) {
242 pr_debug("md/raid0:%s: checking %s ... nope\n",
243 mdname(mddev),
244 bdevname(rdev->bdev, b));
245 continue;
246 }
247 pr_debug("md/raid0:%s: checking %s ..."
248 " contained as device %d\n",
249 mdname(mddev),
250 bdevname(rdev->bdev, b), c);
251 dev[c] = rdev;
252 c++;
253 if (!smallest || rdev->sectors < smallest->sectors) {
254 smallest = rdev;
255 pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
256 mdname(mddev),
257 (unsigned long long)rdev->sectors);
258 }
259 }
260
261 zone->nb_dev = c;
262 sectors = (smallest->sectors - zone->dev_start) * c;
263 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
264 mdname(mddev),
265 zone->nb_dev, (unsigned long long)sectors);
266
267 curr_zone_end += sectors;
268 zone->zone_end = curr_zone_end;
269
270 pr_debug("md/raid0:%s: current zone start: %llu\n",
271 mdname(mddev),
272 (unsigned long long)smallest->sectors);
273 }
274
275 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
276 *private_conf = conf;
277
278 return 0;
279abort:
280 kfree(conf->strip_zone);
281 kfree(conf->devlist);
282 kfree(conf);
283 *private_conf = ERR_PTR(err);
284 return err;
285}
286
287/* Find the zone which holds a particular offset
288 * Update *sectorp to be an offset in that zone
289 */
290static struct strip_zone *find_zone(struct r0conf *conf,
291 sector_t *sectorp)
292{
293 int i;
294 struct strip_zone *z = conf->strip_zone;
295 sector_t sector = *sectorp;
296
297 for (i = 0; i < conf->nr_strip_zones; i++)
298 if (sector < z[i].zone_end) {
299 if (i)
300 *sectorp = sector - z[i-1].zone_end;
301 return z + i;
302 }
303 BUG();
304}
305
306/*
307 * remaps the bio to the target device. we separate two flows.
308 * power 2 flow and a general flow for the sake of performance
309*/
310static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
311 sector_t sector, sector_t *sector_offset)
312{
313 unsigned int sect_in_chunk;
314 sector_t chunk;
315 struct r0conf *conf = mddev->private;
316 int raid_disks = conf->strip_zone[0].nb_dev;
317 unsigned int chunk_sects = mddev->chunk_sectors;
318
319 if (is_power_of_2(chunk_sects)) {
320 int chunksect_bits = ffz(~chunk_sects);
321 /* find the sector offset inside the chunk */
322 sect_in_chunk = sector & (chunk_sects - 1);
323 sector >>= chunksect_bits;
324 /* chunk in zone */
325 chunk = *sector_offset;
326 /* quotient is the chunk in real device*/
327 sector_div(chunk, zone->nb_dev << chunksect_bits);
328 } else{
329 sect_in_chunk = sector_div(sector, chunk_sects);
330 chunk = *sector_offset;
331 sector_div(chunk, chunk_sects * zone->nb_dev);
332 }
333 /*
334 * position the bio over the real device
335 * real sector = chunk in device + starting of zone
336 * + the position in the chunk
337 */
338 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
339 return conf->devlist[(zone - conf->strip_zone)*raid_disks
340 + sector_div(sector, zone->nb_dev)];
341}
342
343static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
344{
345 sector_t array_sectors = 0;
346 struct md_rdev *rdev;
347
348 WARN_ONCE(sectors || raid_disks,
349 "%s does not support generic reshape\n", __func__);
350
351 rdev_for_each(rdev, mddev)
352 array_sectors += (rdev->sectors &
353 ~(sector_t)(mddev->chunk_sectors-1));
354
355 return array_sectors;
356}
357
358static void raid0_free(struct mddev *mddev, void *priv);
359
360static int raid0_run(struct mddev *mddev)
361{
362 struct r0conf *conf;
363 int ret;
364
365 if (mddev->chunk_sectors == 0) {
366 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
367 return -EINVAL;
368 }
369 if (md_check_no_bitmap(mddev))
370 return -EINVAL;
371
372 /* if private is not null, we are here after takeover */
373 if (mddev->private == NULL) {
374 ret = create_strip_zones(mddev, &conf);
375 if (ret < 0)
376 return ret;
377 mddev->private = conf;
378 }
379 conf = mddev->private;
380 if (mddev->queue) {
381 struct md_rdev *rdev;
382 bool discard_supported = false;
383
384 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
385 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
386 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);
387
388 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
389 blk_queue_io_opt(mddev->queue,
390 (mddev->chunk_sectors << 9) * mddev->raid_disks);
391
392 rdev_for_each(rdev, mddev) {
393 disk_stack_limits(mddev->gendisk, rdev->bdev,
394 rdev->data_offset << 9);
395 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
396 discard_supported = true;
397 }
398 if (!discard_supported)
399 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
400 else
401 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
402 }
403
404 /* calculate array device size */
405 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
406
407 pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
408 mdname(mddev),
409 (unsigned long long)mddev->array_sectors);
410
411 if (mddev->queue) {
412 /* calculate the max read-ahead size.
413 * For read-ahead of large files to be effective, we need to
414 * readahead at least twice a whole stripe. i.e. number of devices
415 * multiplied by chunk size times 2.
416 * If an individual device has an ra_pages greater than the
417 * chunk size, then we will not drive that device as hard as it
418 * wants. We consider this a configuration error: a larger
419 * chunksize should be used in that case.
420 */
421 int stripe = mddev->raid_disks *
422 (mddev->chunk_sectors << 9) / PAGE_SIZE;
423 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
424 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
425 }
426
427 dump_zones(mddev);
428
429 ret = md_integrity_register(mddev);
430
431 return ret;
432}
433
434static void raid0_free(struct mddev *mddev, void *priv)
435{
436 struct r0conf *conf = priv;
437
438 kfree(conf->strip_zone);
439 kfree(conf->devlist);
440 kfree(conf);
441}
442
443/*
444 * Is io distribute over 1 or more chunks ?
445*/
446static inline int is_io_in_chunk_boundary(struct mddev *mddev,
447 unsigned int chunk_sects, struct bio *bio)
448{
449 if (likely(is_power_of_2(chunk_sects))) {
450 return chunk_sects >=
451 ((bio->bi_iter.bi_sector & (chunk_sects-1))
452 + bio_sectors(bio));
453 } else{
454 sector_t sector = bio->bi_iter.bi_sector;
455 return chunk_sects >= (sector_div(sector, chunk_sects)
456 + bio_sectors(bio));
457 }
458}
459
460static void raid0_make_request(struct mddev *mddev, struct bio *bio)
461{
462 struct strip_zone *zone;
463 struct md_rdev *tmp_dev;
464 struct bio *split;
465
466 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
467 md_flush_request(mddev, bio);
468 return;
469 }
470
471 do {
472 sector_t bio_sector = bio->bi_iter.bi_sector;
473 sector_t sector = bio_sector;
474 unsigned chunk_sects = mddev->chunk_sectors;
475
476 unsigned sectors = chunk_sects -
477 (likely(is_power_of_2(chunk_sects))
478 ? (sector & (chunk_sects-1))
479 : sector_div(sector, chunk_sects));
480
481 /* Restore due to sector_div */
482 sector = bio_sector;
483
484 if (sectors < bio_sectors(bio)) {
485 split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
486 bio_chain(split, bio);
487 } else {
488 split = bio;
489 }
490
491 zone = find_zone(mddev->private, §or);
492 tmp_dev = map_sector(mddev, zone, sector, §or);
493 split->bi_bdev = tmp_dev->bdev;
494 split->bi_iter.bi_sector = sector + zone->dev_start +
495 tmp_dev->data_offset;
496
497 if (unlikely((bio_op(split) == REQ_OP_DISCARD) &&
498 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
499 /* Just ignore it */
500 bio_endio(split);
501 } else {
502 if (mddev->gendisk)
503 trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
504 split, disk_devt(mddev->gendisk),
505 bio_sector);
506 generic_make_request(split);
507 }
508 } while (split != bio);
509}
510
511static void raid0_status(struct seq_file *seq, struct mddev *mddev)
512{
513 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
514 return;
515}
516
517static void *raid0_takeover_raid45(struct mddev *mddev)
518{
519 struct md_rdev *rdev;
520 struct r0conf *priv_conf;
521
522 if (mddev->degraded != 1) {
523 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
524 mdname(mddev),
525 mddev->degraded);
526 return ERR_PTR(-EINVAL);
527 }
528
529 rdev_for_each(rdev, mddev) {
530 /* check slot number for a disk */
531 if (rdev->raid_disk == mddev->raid_disks-1) {
532 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
533 mdname(mddev));
534 return ERR_PTR(-EINVAL);
535 }
536 rdev->sectors = mddev->dev_sectors;
537 }
538
539 /* Set new parameters */
540 mddev->new_level = 0;
541 mddev->new_layout = 0;
542 mddev->new_chunk_sectors = mddev->chunk_sectors;
543 mddev->raid_disks--;
544 mddev->delta_disks = -1;
545 /* make sure it will be not marked as dirty */
546 mddev->recovery_cp = MaxSector;
547 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
548
549 create_strip_zones(mddev, &priv_conf);
550
551 return priv_conf;
552}
553
554static void *raid0_takeover_raid10(struct mddev *mddev)
555{
556 struct r0conf *priv_conf;
557
558 /* Check layout:
559 * - far_copies must be 1
560 * - near_copies must be 2
561 * - disks number must be even
562 * - all mirrors must be already degraded
563 */
564 if (mddev->layout != ((1 << 8) + 2)) {
565 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
566 mdname(mddev),
567 mddev->layout);
568 return ERR_PTR(-EINVAL);
569 }
570 if (mddev->raid_disks & 1) {
571 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
572 mdname(mddev));
573 return ERR_PTR(-EINVAL);
574 }
575 if (mddev->degraded != (mddev->raid_disks>>1)) {
576 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
577 mdname(mddev));
578 return ERR_PTR(-EINVAL);
579 }
580
581 /* Set new parameters */
582 mddev->new_level = 0;
583 mddev->new_layout = 0;
584 mddev->new_chunk_sectors = mddev->chunk_sectors;
585 mddev->delta_disks = - mddev->raid_disks / 2;
586 mddev->raid_disks += mddev->delta_disks;
587 mddev->degraded = 0;
588 /* make sure it will be not marked as dirty */
589 mddev->recovery_cp = MaxSector;
590 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
591
592 create_strip_zones(mddev, &priv_conf);
593 return priv_conf;
594}
595
596static void *raid0_takeover_raid1(struct mddev *mddev)
597{
598 struct r0conf *priv_conf;
599 int chunksect;
600
601 /* Check layout:
602 * - (N - 1) mirror drives must be already faulty
603 */
604 if ((mddev->raid_disks - 1) != mddev->degraded) {
605 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
606 mdname(mddev));
607 return ERR_PTR(-EINVAL);
608 }
609
610 /*
611 * a raid1 doesn't have the notion of chunk size, so
612 * figure out the largest suitable size we can use.
613 */
614 chunksect = 64 * 2; /* 64K by default */
615
616 /* The array must be an exact multiple of chunksize */
617 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
618 chunksect >>= 1;
619
620 if ((chunksect << 9) < PAGE_SIZE)
621 /* array size does not allow a suitable chunk size */
622 return ERR_PTR(-EINVAL);
623
624 /* Set new parameters */
625 mddev->new_level = 0;
626 mddev->new_layout = 0;
627 mddev->new_chunk_sectors = chunksect;
628 mddev->chunk_sectors = chunksect;
629 mddev->delta_disks = 1 - mddev->raid_disks;
630 mddev->raid_disks = 1;
631 /* make sure it will be not marked as dirty */
632 mddev->recovery_cp = MaxSector;
633 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
634
635 create_strip_zones(mddev, &priv_conf);
636 return priv_conf;
637}
638
639static void *raid0_takeover(struct mddev *mddev)
640{
641 /* raid0 can take over:
642 * raid4 - if all data disks are active.
643 * raid5 - providing it is Raid4 layout and one disk is faulty
644 * raid10 - assuming we have all necessary active disks
645 * raid1 - with (N -1) mirror drives faulty
646 */
647
648 if (mddev->bitmap) {
649 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
650 mdname(mddev));
651 return ERR_PTR(-EBUSY);
652 }
653 if (mddev->level == 4)
654 return raid0_takeover_raid45(mddev);
655
656 if (mddev->level == 5) {
657 if (mddev->layout == ALGORITHM_PARITY_N)
658 return raid0_takeover_raid45(mddev);
659
660 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
661 mdname(mddev), ALGORITHM_PARITY_N);
662 }
663
664 if (mddev->level == 10)
665 return raid0_takeover_raid10(mddev);
666
667 if (mddev->level == 1)
668 return raid0_takeover_raid1(mddev);
669
670 pr_warn("Takeover from raid%i to raid0 not supported\n",
671 mddev->level);
672
673 return ERR_PTR(-EINVAL);
674}
675
676static void raid0_quiesce(struct mddev *mddev, int state)
677{
678}
679
680static struct md_personality raid0_personality=
681{
682 .name = "raid0",
683 .level = 0,
684 .owner = THIS_MODULE,
685 .make_request = raid0_make_request,
686 .run = raid0_run,
687 .free = raid0_free,
688 .status = raid0_status,
689 .size = raid0_size,
690 .takeover = raid0_takeover,
691 .quiesce = raid0_quiesce,
692 .congested = raid0_congested,
693};
694
695static int __init raid0_init (void)
696{
697 return register_md_personality (&raid0_personality);
698}
699
700static void raid0_exit (void)
701{
702 unregister_md_personality (&raid0_personality);
703}
704
705module_init(raid0_init);
706module_exit(raid0_exit);
707MODULE_LICENSE("GPL");
708MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
709MODULE_ALIAS("md-personality-2"); /* RAID0 */
710MODULE_ALIAS("md-raid0");
711MODULE_ALIAS("md-level-0");