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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 raid0.c : Multiple Devices driver for Linux
4 Copyright (C) 1994-96 Marc ZYNGIER
5 <zyngier@ufr-info-p7.ibp.fr> or
6 <maz@gloups.fdn.fr>
7 Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
8
9 RAID-0 management functions.
10
11*/
12
13#include <linux/blkdev.h>
14#include <linux/seq_file.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <trace/events/block.h>
18#include "md.h"
19#include "raid0.h"
20#include "raid5.h"
21
22static int default_layout = 0;
23module_param(default_layout, int, 0644);
24
25#define UNSUPPORTED_MDDEV_FLAGS \
26 ((1L << MD_HAS_JOURNAL) | \
27 (1L << MD_JOURNAL_CLEAN) | \
28 (1L << MD_FAILFAST_SUPPORTED) |\
29 (1L << MD_HAS_PPL) | \
30 (1L << MD_HAS_MULTIPLE_PPLS))
31
32/*
33 * inform the user of the raid configuration
34*/
35static void dump_zones(struct mddev *mddev)
36{
37 int j, k;
38 sector_t zone_size = 0;
39 sector_t zone_start = 0;
40 struct r0conf *conf = mddev->private;
41 int raid_disks = conf->strip_zone[0].nb_dev;
42 pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
43 mdname(mddev),
44 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
45 for (j = 0; j < conf->nr_strip_zones; j++) {
46 char line[200];
47 int len = 0;
48
49 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
50 len += scnprintf(line+len, 200-len, "%s%pg", k?"/":"",
51 conf->devlist[j * raid_disks + k]->bdev);
52 pr_debug("md: zone%d=[%s]\n", j, line);
53
54 zone_size = conf->strip_zone[j].zone_end - zone_start;
55 pr_debug(" zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n",
56 (unsigned long long)zone_start>>1,
57 (unsigned long long)conf->strip_zone[j].dev_start>>1,
58 (unsigned long long)zone_size>>1);
59 zone_start = conf->strip_zone[j].zone_end;
60 }
61}
62
63static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
64{
65 int i, c, err;
66 sector_t curr_zone_end, sectors;
67 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
68 struct strip_zone *zone;
69 int cnt;
70 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
71 unsigned blksize = 512;
72
73 *private_conf = ERR_PTR(-ENOMEM);
74 if (!conf)
75 return -ENOMEM;
76 rdev_for_each(rdev1, mddev) {
77 pr_debug("md/raid0:%s: looking at %pg\n",
78 mdname(mddev),
79 rdev1->bdev);
80 c = 0;
81
82 /* round size to chunk_size */
83 sectors = rdev1->sectors;
84 sector_div(sectors, mddev->chunk_sectors);
85 rdev1->sectors = sectors * mddev->chunk_sectors;
86
87 blksize = max(blksize, queue_logical_block_size(
88 rdev1->bdev->bd_disk->queue));
89
90 rdev_for_each(rdev2, mddev) {
91 pr_debug("md/raid0:%s: comparing %pg(%llu)"
92 " with %pg(%llu)\n",
93 mdname(mddev),
94 rdev1->bdev,
95 (unsigned long long)rdev1->sectors,
96 rdev2->bdev,
97 (unsigned long long)rdev2->sectors);
98 if (rdev2 == rdev1) {
99 pr_debug("md/raid0:%s: END\n",
100 mdname(mddev));
101 break;
102 }
103 if (rdev2->sectors == rdev1->sectors) {
104 /*
105 * Not unique, don't count it as a new
106 * group
107 */
108 pr_debug("md/raid0:%s: EQUAL\n",
109 mdname(mddev));
110 c = 1;
111 break;
112 }
113 pr_debug("md/raid0:%s: NOT EQUAL\n",
114 mdname(mddev));
115 }
116 if (!c) {
117 pr_debug("md/raid0:%s: ==> UNIQUE\n",
118 mdname(mddev));
119 conf->nr_strip_zones++;
120 pr_debug("md/raid0:%s: %d zones\n",
121 mdname(mddev), conf->nr_strip_zones);
122 }
123 }
124 pr_debug("md/raid0:%s: FINAL %d zones\n",
125 mdname(mddev), conf->nr_strip_zones);
126
127 /*
128 * now since we have the hard sector sizes, we can make sure
129 * chunk size is a multiple of that sector size
130 */
131 if ((mddev->chunk_sectors << 9) % blksize) {
132 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
133 mdname(mddev),
134 mddev->chunk_sectors << 9, blksize);
135 err = -EINVAL;
136 goto abort;
137 }
138
139 err = -ENOMEM;
140 conf->strip_zone = kcalloc(conf->nr_strip_zones,
141 sizeof(struct strip_zone),
142 GFP_KERNEL);
143 if (!conf->strip_zone)
144 goto abort;
145 conf->devlist = kzalloc(array3_size(sizeof(struct md_rdev *),
146 conf->nr_strip_zones,
147 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 pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
179 mdname(mddev));
180 goto abort;
181 }
182 if (j >= mddev->raid_disks) {
183 pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
184 mdname(mddev), j);
185 goto abort;
186 }
187 if (dev[j]) {
188 pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
189 mdname(mddev), j);
190 goto abort;
191 }
192 dev[j] = rdev1;
193
194 if (!smallest || (rdev1->sectors < smallest->sectors))
195 smallest = rdev1;
196 cnt++;
197 }
198 if (cnt != mddev->raid_disks) {
199 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
200 mdname(mddev), cnt, mddev->raid_disks);
201 goto abort;
202 }
203 zone->nb_dev = cnt;
204 zone->zone_end = smallest->sectors * cnt;
205
206 curr_zone_end = zone->zone_end;
207
208 /* now do the other zones */
209 for (i = 1; i < conf->nr_strip_zones; i++)
210 {
211 int j;
212
213 zone = conf->strip_zone + i;
214 dev = conf->devlist + i * mddev->raid_disks;
215
216 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
217 zone->dev_start = smallest->sectors;
218 smallest = NULL;
219 c = 0;
220
221 for (j=0; j<cnt; j++) {
222 rdev = conf->devlist[j];
223 if (rdev->sectors <= zone->dev_start) {
224 pr_debug("md/raid0:%s: checking %pg ... nope\n",
225 mdname(mddev),
226 rdev->bdev);
227 continue;
228 }
229 pr_debug("md/raid0:%s: checking %pg ..."
230 " contained as device %d\n",
231 mdname(mddev),
232 rdev->bdev, c);
233 dev[c] = rdev;
234 c++;
235 if (!smallest || rdev->sectors < smallest->sectors) {
236 smallest = rdev;
237 pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
238 mdname(mddev),
239 (unsigned long long)rdev->sectors);
240 }
241 }
242
243 zone->nb_dev = c;
244 sectors = (smallest->sectors - zone->dev_start) * c;
245 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
246 mdname(mddev),
247 zone->nb_dev, (unsigned long long)sectors);
248
249 curr_zone_end += sectors;
250 zone->zone_end = curr_zone_end;
251
252 pr_debug("md/raid0:%s: current zone start: %llu\n",
253 mdname(mddev),
254 (unsigned long long)smallest->sectors);
255 }
256
257 if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) {
258 conf->layout = RAID0_ORIG_LAYOUT;
259 } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
260 mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
261 conf->layout = mddev->layout;
262 } else if (default_layout == RAID0_ORIG_LAYOUT ||
263 default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
264 conf->layout = default_layout;
265 } else {
266 pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
267 mdname(mddev));
268 pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
269 err = -EOPNOTSUPP;
270 goto abort;
271 }
272
273 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
274 *private_conf = conf;
275
276 return 0;
277abort:
278 kfree(conf->strip_zone);
279 kfree(conf->devlist);
280 kfree(conf);
281 *private_conf = ERR_PTR(err);
282 return err;
283}
284
285/* Find the zone which holds a particular offset
286 * Update *sectorp to be an offset in that zone
287 */
288static struct strip_zone *find_zone(struct r0conf *conf,
289 sector_t *sectorp)
290{
291 int i;
292 struct strip_zone *z = conf->strip_zone;
293 sector_t sector = *sectorp;
294
295 for (i = 0; i < conf->nr_strip_zones; i++)
296 if (sector < z[i].zone_end) {
297 if (i)
298 *sectorp = sector - z[i-1].zone_end;
299 return z + i;
300 }
301 BUG();
302}
303
304/*
305 * remaps the bio to the target device. we separate two flows.
306 * power 2 flow and a general flow for the sake of performance
307*/
308static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
309 sector_t sector, sector_t *sector_offset)
310{
311 unsigned int sect_in_chunk;
312 sector_t chunk;
313 struct r0conf *conf = mddev->private;
314 int raid_disks = conf->strip_zone[0].nb_dev;
315 unsigned int chunk_sects = mddev->chunk_sectors;
316
317 if (is_power_of_2(chunk_sects)) {
318 int chunksect_bits = ffz(~chunk_sects);
319 /* find the sector offset inside the chunk */
320 sect_in_chunk = sector & (chunk_sects - 1);
321 sector >>= chunksect_bits;
322 /* chunk in zone */
323 chunk = *sector_offset;
324 /* quotient is the chunk in real device*/
325 sector_div(chunk, zone->nb_dev << chunksect_bits);
326 } else{
327 sect_in_chunk = sector_div(sector, chunk_sects);
328 chunk = *sector_offset;
329 sector_div(chunk, chunk_sects * zone->nb_dev);
330 }
331 /*
332 * position the bio over the real device
333 * real sector = chunk in device + starting of zone
334 * + the position in the chunk
335 */
336 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
337 return conf->devlist[(zone - conf->strip_zone)*raid_disks
338 + sector_div(sector, zone->nb_dev)];
339}
340
341static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
342{
343 sector_t array_sectors = 0;
344 struct md_rdev *rdev;
345
346 WARN_ONCE(sectors || raid_disks,
347 "%s does not support generic reshape\n", __func__);
348
349 rdev_for_each(rdev, mddev)
350 array_sectors += (rdev->sectors &
351 ~(sector_t)(mddev->chunk_sectors-1));
352
353 return array_sectors;
354}
355
356static void free_conf(struct mddev *mddev, struct r0conf *conf)
357{
358 kfree(conf->strip_zone);
359 kfree(conf->devlist);
360 kfree(conf);
361}
362
363static void raid0_free(struct mddev *mddev, void *priv)
364{
365 struct r0conf *conf = priv;
366
367 free_conf(mddev, conf);
368 acct_bioset_exit(mddev);
369}
370
371static int raid0_run(struct mddev *mddev)
372{
373 struct r0conf *conf;
374 int ret;
375
376 if (mddev->chunk_sectors == 0) {
377 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
378 return -EINVAL;
379 }
380 if (md_check_no_bitmap(mddev))
381 return -EINVAL;
382
383 if (acct_bioset_init(mddev)) {
384 pr_err("md/raid0:%s: alloc acct bioset failed.\n", mdname(mddev));
385 return -ENOMEM;
386 }
387
388 /* if private is not null, we are here after takeover */
389 if (mddev->private == NULL) {
390 ret = create_strip_zones(mddev, &conf);
391 if (ret < 0)
392 goto exit_acct_set;
393 mddev->private = conf;
394 }
395 conf = mddev->private;
396 if (mddev->queue) {
397 struct md_rdev *rdev;
398
399 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
400 blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors);
401
402 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
403 blk_queue_io_opt(mddev->queue,
404 (mddev->chunk_sectors << 9) * mddev->raid_disks);
405
406 rdev_for_each(rdev, mddev) {
407 disk_stack_limits(mddev->gendisk, rdev->bdev,
408 rdev->data_offset << 9);
409 }
410 }
411
412 /* calculate array device size */
413 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
414
415 pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
416 mdname(mddev),
417 (unsigned long long)mddev->array_sectors);
418
419 dump_zones(mddev);
420
421 ret = md_integrity_register(mddev);
422 if (ret)
423 goto free;
424
425 return ret;
426
427free:
428 free_conf(mddev, conf);
429exit_acct_set:
430 acct_bioset_exit(mddev);
431 return ret;
432}
433
434static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
435{
436 struct r0conf *conf = mddev->private;
437 struct strip_zone *zone;
438 sector_t start = bio->bi_iter.bi_sector;
439 sector_t end;
440 unsigned int stripe_size;
441 sector_t first_stripe_index, last_stripe_index;
442 sector_t start_disk_offset;
443 unsigned int start_disk_index;
444 sector_t end_disk_offset;
445 unsigned int end_disk_index;
446 unsigned int disk;
447
448 zone = find_zone(conf, &start);
449
450 if (bio_end_sector(bio) > zone->zone_end) {
451 struct bio *split = bio_split(bio,
452 zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO,
453 &mddev->bio_set);
454 bio_chain(split, bio);
455 submit_bio_noacct(bio);
456 bio = split;
457 end = zone->zone_end;
458 } else
459 end = bio_end_sector(bio);
460
461 if (zone != conf->strip_zone)
462 end = end - zone[-1].zone_end;
463
464 /* Now start and end is the offset in zone */
465 stripe_size = zone->nb_dev * mddev->chunk_sectors;
466
467 first_stripe_index = start;
468 sector_div(first_stripe_index, stripe_size);
469 last_stripe_index = end;
470 sector_div(last_stripe_index, stripe_size);
471
472 start_disk_index = (int)(start - first_stripe_index * stripe_size) /
473 mddev->chunk_sectors;
474 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
475 mddev->chunk_sectors) +
476 first_stripe_index * mddev->chunk_sectors;
477 end_disk_index = (int)(end - last_stripe_index * stripe_size) /
478 mddev->chunk_sectors;
479 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
480 mddev->chunk_sectors) +
481 last_stripe_index * mddev->chunk_sectors;
482
483 for (disk = 0; disk < zone->nb_dev; disk++) {
484 sector_t dev_start, dev_end;
485 struct md_rdev *rdev;
486
487 if (disk < start_disk_index)
488 dev_start = (first_stripe_index + 1) *
489 mddev->chunk_sectors;
490 else if (disk > start_disk_index)
491 dev_start = first_stripe_index * mddev->chunk_sectors;
492 else
493 dev_start = start_disk_offset;
494
495 if (disk < end_disk_index)
496 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
497 else if (disk > end_disk_index)
498 dev_end = last_stripe_index * mddev->chunk_sectors;
499 else
500 dev_end = end_disk_offset;
501
502 if (dev_end <= dev_start)
503 continue;
504
505 rdev = conf->devlist[(zone - conf->strip_zone) *
506 conf->strip_zone[0].nb_dev + disk];
507 md_submit_discard_bio(mddev, rdev, bio,
508 dev_start + zone->dev_start + rdev->data_offset,
509 dev_end - dev_start);
510 }
511 bio_endio(bio);
512}
513
514static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
515{
516 struct r0conf *conf = mddev->private;
517 struct strip_zone *zone;
518 struct md_rdev *tmp_dev;
519 sector_t bio_sector;
520 sector_t sector;
521 sector_t orig_sector;
522 unsigned chunk_sects;
523 unsigned sectors;
524
525 if (unlikely(bio->bi_opf & REQ_PREFLUSH)
526 && md_flush_request(mddev, bio))
527 return true;
528
529 if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
530 raid0_handle_discard(mddev, bio);
531 return true;
532 }
533
534 bio_sector = bio->bi_iter.bi_sector;
535 sector = bio_sector;
536 chunk_sects = mddev->chunk_sectors;
537
538 sectors = chunk_sects -
539 (likely(is_power_of_2(chunk_sects))
540 ? (sector & (chunk_sects-1))
541 : sector_div(sector, chunk_sects));
542
543 /* Restore due to sector_div */
544 sector = bio_sector;
545
546 if (sectors < bio_sectors(bio)) {
547 struct bio *split = bio_split(bio, sectors, GFP_NOIO,
548 &mddev->bio_set);
549 bio_chain(split, bio);
550 submit_bio_noacct(bio);
551 bio = split;
552 }
553
554 if (bio->bi_pool != &mddev->bio_set)
555 md_account_bio(mddev, &bio);
556
557 orig_sector = sector;
558 zone = find_zone(mddev->private, §or);
559 switch (conf->layout) {
560 case RAID0_ORIG_LAYOUT:
561 tmp_dev = map_sector(mddev, zone, orig_sector, §or);
562 break;
563 case RAID0_ALT_MULTIZONE_LAYOUT:
564 tmp_dev = map_sector(mddev, zone, sector, §or);
565 break;
566 default:
567 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
568 bio_io_error(bio);
569 return true;
570 }
571
572 if (unlikely(is_mddev_broken(tmp_dev, "raid0"))) {
573 bio_io_error(bio);
574 return true;
575 }
576
577 bio_set_dev(bio, tmp_dev->bdev);
578 bio->bi_iter.bi_sector = sector + zone->dev_start +
579 tmp_dev->data_offset;
580
581 if (mddev->gendisk)
582 trace_block_bio_remap(bio, disk_devt(mddev->gendisk),
583 bio_sector);
584 mddev_check_write_zeroes(mddev, bio);
585 submit_bio_noacct(bio);
586 return true;
587}
588
589static void raid0_status(struct seq_file *seq, struct mddev *mddev)
590{
591 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
592 return;
593}
594
595static void *raid0_takeover_raid45(struct mddev *mddev)
596{
597 struct md_rdev *rdev;
598 struct r0conf *priv_conf;
599
600 if (mddev->degraded != 1) {
601 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
602 mdname(mddev),
603 mddev->degraded);
604 return ERR_PTR(-EINVAL);
605 }
606
607 rdev_for_each(rdev, mddev) {
608 /* check slot number for a disk */
609 if (rdev->raid_disk == mddev->raid_disks-1) {
610 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
611 mdname(mddev));
612 return ERR_PTR(-EINVAL);
613 }
614 rdev->sectors = mddev->dev_sectors;
615 }
616
617 /* Set new parameters */
618 mddev->new_level = 0;
619 mddev->new_layout = 0;
620 mddev->new_chunk_sectors = mddev->chunk_sectors;
621 mddev->raid_disks--;
622 mddev->delta_disks = -1;
623 /* make sure it will be not marked as dirty */
624 mddev->recovery_cp = MaxSector;
625 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
626
627 create_strip_zones(mddev, &priv_conf);
628
629 return priv_conf;
630}
631
632static void *raid0_takeover_raid10(struct mddev *mddev)
633{
634 struct r0conf *priv_conf;
635
636 /* Check layout:
637 * - far_copies must be 1
638 * - near_copies must be 2
639 * - disks number must be even
640 * - all mirrors must be already degraded
641 */
642 if (mddev->layout != ((1 << 8) + 2)) {
643 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
644 mdname(mddev),
645 mddev->layout);
646 return ERR_PTR(-EINVAL);
647 }
648 if (mddev->raid_disks & 1) {
649 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
650 mdname(mddev));
651 return ERR_PTR(-EINVAL);
652 }
653 if (mddev->degraded != (mddev->raid_disks>>1)) {
654 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
655 mdname(mddev));
656 return ERR_PTR(-EINVAL);
657 }
658
659 /* Set new parameters */
660 mddev->new_level = 0;
661 mddev->new_layout = 0;
662 mddev->new_chunk_sectors = mddev->chunk_sectors;
663 mddev->delta_disks = - mddev->raid_disks / 2;
664 mddev->raid_disks += mddev->delta_disks;
665 mddev->degraded = 0;
666 /* make sure it will be not marked as dirty */
667 mddev->recovery_cp = MaxSector;
668 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
669
670 create_strip_zones(mddev, &priv_conf);
671 return priv_conf;
672}
673
674static void *raid0_takeover_raid1(struct mddev *mddev)
675{
676 struct r0conf *priv_conf;
677 int chunksect;
678
679 /* Check layout:
680 * - (N - 1) mirror drives must be already faulty
681 */
682 if ((mddev->raid_disks - 1) != mddev->degraded) {
683 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
684 mdname(mddev));
685 return ERR_PTR(-EINVAL);
686 }
687
688 /*
689 * a raid1 doesn't have the notion of chunk size, so
690 * figure out the largest suitable size we can use.
691 */
692 chunksect = 64 * 2; /* 64K by default */
693
694 /* The array must be an exact multiple of chunksize */
695 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
696 chunksect >>= 1;
697
698 if ((chunksect << 9) < PAGE_SIZE)
699 /* array size does not allow a suitable chunk size */
700 return ERR_PTR(-EINVAL);
701
702 /* Set new parameters */
703 mddev->new_level = 0;
704 mddev->new_layout = 0;
705 mddev->new_chunk_sectors = chunksect;
706 mddev->chunk_sectors = chunksect;
707 mddev->delta_disks = 1 - mddev->raid_disks;
708 mddev->raid_disks = 1;
709 /* make sure it will be not marked as dirty */
710 mddev->recovery_cp = MaxSector;
711 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
712
713 create_strip_zones(mddev, &priv_conf);
714 return priv_conf;
715}
716
717static void *raid0_takeover(struct mddev *mddev)
718{
719 /* raid0 can take over:
720 * raid4 - if all data disks are active.
721 * raid5 - providing it is Raid4 layout and one disk is faulty
722 * raid10 - assuming we have all necessary active disks
723 * raid1 - with (N -1) mirror drives faulty
724 */
725
726 if (mddev->bitmap) {
727 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
728 mdname(mddev));
729 return ERR_PTR(-EBUSY);
730 }
731 if (mddev->level == 4)
732 return raid0_takeover_raid45(mddev);
733
734 if (mddev->level == 5) {
735 if (mddev->layout == ALGORITHM_PARITY_N)
736 return raid0_takeover_raid45(mddev);
737
738 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
739 mdname(mddev), ALGORITHM_PARITY_N);
740 }
741
742 if (mddev->level == 10)
743 return raid0_takeover_raid10(mddev);
744
745 if (mddev->level == 1)
746 return raid0_takeover_raid1(mddev);
747
748 pr_warn("Takeover from raid%i to raid0 not supported\n",
749 mddev->level);
750
751 return ERR_PTR(-EINVAL);
752}
753
754static void raid0_quiesce(struct mddev *mddev, int quiesce)
755{
756}
757
758static struct md_personality raid0_personality=
759{
760 .name = "raid0",
761 .level = 0,
762 .owner = THIS_MODULE,
763 .make_request = raid0_make_request,
764 .run = raid0_run,
765 .free = raid0_free,
766 .status = raid0_status,
767 .size = raid0_size,
768 .takeover = raid0_takeover,
769 .quiesce = raid0_quiesce,
770};
771
772static int __init raid0_init (void)
773{
774 return register_md_personality (&raid0_personality);
775}
776
777static void raid0_exit (void)
778{
779 unregister_md_personality (&raid0_personality);
780}
781
782module_init(raid0_init);
783module_exit(raid0_exit);
784MODULE_LICENSE("GPL");
785MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
786MODULE_ALIAS("md-personality-2"); /* RAID0 */
787MODULE_ALIAS("md-raid0");
788MODULE_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 "md.h"
25#include "raid0.h"
26#include "raid5.h"
27
28static int raid0_congested(struct mddev *mddev, int bits)
29{
30 struct r0conf *conf = mddev->private;
31 struct md_rdev **devlist = conf->devlist;
32 int raid_disks = conf->strip_zone[0].nb_dev;
33 int i, ret = 0;
34
35 for (i = 0; i < raid_disks && !ret ; i++) {
36 struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
37
38 ret |= bdi_congested(&q->backing_dev_info, bits);
39 }
40 return ret;
41}
42
43/*
44 * inform the user of the raid configuration
45*/
46static void dump_zones(struct mddev *mddev)
47{
48 int j, k;
49 sector_t zone_size = 0;
50 sector_t zone_start = 0;
51 char b[BDEVNAME_SIZE];
52 struct r0conf *conf = mddev->private;
53 int raid_disks = conf->strip_zone[0].nb_dev;
54 printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n",
55 mdname(mddev),
56 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
57 for (j = 0; j < conf->nr_strip_zones; j++) {
58 printk(KERN_INFO "md: zone%d=[", j);
59 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
60 printk(KERN_CONT "%s%s", k?"/":"",
61 bdevname(conf->devlist[j*raid_disks
62 + k]->bdev, b));
63 printk(KERN_CONT "]\n");
64
65 zone_size = conf->strip_zone[j].zone_end - zone_start;
66 printk(KERN_INFO " zone-offset=%10lluKB, "
67 "device-offset=%10lluKB, size=%10lluKB\n",
68 (unsigned long long)zone_start>>1,
69 (unsigned long long)conf->strip_zone[j].dev_start>>1,
70 (unsigned long long)zone_size>>1);
71 zone_start = conf->strip_zone[j].zone_end;
72 }
73}
74
75static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
76{
77 int i, c, err;
78 sector_t curr_zone_end, sectors;
79 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
80 struct strip_zone *zone;
81 int cnt;
82 char b[BDEVNAME_SIZE];
83 char b2[BDEVNAME_SIZE];
84 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
85 unsigned short blksize = 512;
86
87 *private_conf = ERR_PTR(-ENOMEM);
88 if (!conf)
89 return -ENOMEM;
90 rdev_for_each(rdev1, mddev) {
91 pr_debug("md/raid0:%s: looking at %s\n",
92 mdname(mddev),
93 bdevname(rdev1->bdev, b));
94 c = 0;
95
96 /* round size to chunk_size */
97 sectors = rdev1->sectors;
98 sector_div(sectors, mddev->chunk_sectors);
99 rdev1->sectors = sectors * mddev->chunk_sectors;
100
101 blksize = max(blksize, queue_logical_block_size(
102 rdev1->bdev->bd_disk->queue));
103
104 rdev_for_each(rdev2, mddev) {
105 pr_debug("md/raid0:%s: comparing %s(%llu)"
106 " with %s(%llu)\n",
107 mdname(mddev),
108 bdevname(rdev1->bdev,b),
109 (unsigned long long)rdev1->sectors,
110 bdevname(rdev2->bdev,b2),
111 (unsigned long long)rdev2->sectors);
112 if (rdev2 == rdev1) {
113 pr_debug("md/raid0:%s: END\n",
114 mdname(mddev));
115 break;
116 }
117 if (rdev2->sectors == rdev1->sectors) {
118 /*
119 * Not unique, don't count it as a new
120 * group
121 */
122 pr_debug("md/raid0:%s: EQUAL\n",
123 mdname(mddev));
124 c = 1;
125 break;
126 }
127 pr_debug("md/raid0:%s: NOT EQUAL\n",
128 mdname(mddev));
129 }
130 if (!c) {
131 pr_debug("md/raid0:%s: ==> UNIQUE\n",
132 mdname(mddev));
133 conf->nr_strip_zones++;
134 pr_debug("md/raid0:%s: %d zones\n",
135 mdname(mddev), conf->nr_strip_zones);
136 }
137 }
138 pr_debug("md/raid0:%s: FINAL %d zones\n",
139 mdname(mddev), conf->nr_strip_zones);
140 /*
141 * now since we have the hard sector sizes, we can make sure
142 * chunk size is a multiple of that sector size
143 */
144 if ((mddev->chunk_sectors << 9) % blksize) {
145 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
146 mdname(mddev),
147 mddev->chunk_sectors << 9, blksize);
148 err = -EINVAL;
149 goto abort;
150 }
151
152 err = -ENOMEM;
153 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
154 conf->nr_strip_zones, GFP_KERNEL);
155 if (!conf->strip_zone)
156 goto abort;
157 conf->devlist = kzalloc(sizeof(struct md_rdev*)*
158 conf->nr_strip_zones*mddev->raid_disks,
159 GFP_KERNEL);
160 if (!conf->devlist)
161 goto abort;
162
163 /* The first zone must contain all devices, so here we check that
164 * there is a proper alignment of slots to devices and find them all
165 */
166 zone = &conf->strip_zone[0];
167 cnt = 0;
168 smallest = NULL;
169 dev = conf->devlist;
170 err = -EINVAL;
171 rdev_for_each(rdev1, mddev) {
172 int j = rdev1->raid_disk;
173
174 if (mddev->level == 10) {
175 /* taking over a raid10-n2 array */
176 j /= 2;
177 rdev1->new_raid_disk = j;
178 }
179
180 if (mddev->level == 1) {
181 /* taiking over a raid1 array-
182 * we have only one active disk
183 */
184 j = 0;
185 rdev1->new_raid_disk = j;
186 }
187
188 if (j < 0) {
189 printk(KERN_ERR
190 "md/raid0:%s: remove inactive devices before converting to RAID0\n",
191 mdname(mddev));
192 goto abort;
193 }
194 if (j >= mddev->raid_disks) {
195 printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
196 "aborting!\n", mdname(mddev), j);
197 goto abort;
198 }
199 if (dev[j]) {
200 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
201 "aborting!\n", mdname(mddev), j);
202 goto abort;
203 }
204 dev[j] = rdev1;
205
206 if (!smallest || (rdev1->sectors < smallest->sectors))
207 smallest = rdev1;
208 cnt++;
209 }
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;
214 }
215 zone->nb_dev = cnt;
216 zone->zone_end = smallest->sectors * cnt;
217
218 curr_zone_end = zone->zone_end;
219
220 /* now do the other zones */
221 for (i = 1; i < conf->nr_strip_zones; i++)
222 {
223 int j;
224
225 zone = conf->strip_zone + i;
226 dev = conf->devlist + i * mddev->raid_disks;
227
228 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
229 zone->dev_start = smallest->sectors;
230 smallest = NULL;
231 c = 0;
232
233 for (j=0; j<cnt; j++) {
234 rdev = conf->devlist[j];
235 if (rdev->sectors <= zone->dev_start) {
236 pr_debug("md/raid0:%s: checking %s ... nope\n",
237 mdname(mddev),
238 bdevname(rdev->bdev, b));
239 continue;
240 }
241 pr_debug("md/raid0:%s: checking %s ..."
242 " contained as device %d\n",
243 mdname(mddev),
244 bdevname(rdev->bdev, b), c);
245 dev[c] = rdev;
246 c++;
247 if (!smallest || rdev->sectors < smallest->sectors) {
248 smallest = rdev;
249 pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
250 mdname(mddev),
251 (unsigned long long)rdev->sectors);
252 }
253 }
254
255 zone->nb_dev = c;
256 sectors = (smallest->sectors - zone->dev_start) * c;
257 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
258 mdname(mddev),
259 zone->nb_dev, (unsigned long long)sectors);
260
261 curr_zone_end += sectors;
262 zone->zone_end = curr_zone_end;
263
264 pr_debug("md/raid0:%s: current zone start: %llu\n",
265 mdname(mddev),
266 (unsigned long long)smallest->sectors);
267 }
268
269 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
270 *private_conf = conf;
271
272 return 0;
273abort:
274 kfree(conf->strip_zone);
275 kfree(conf->devlist);
276 kfree(conf);
277 *private_conf = ERR_PTR(err);
278 return err;
279}
280
281/* Find the zone which holds a particular offset
282 * Update *sectorp to be an offset in that zone
283 */
284static struct strip_zone *find_zone(struct r0conf *conf,
285 sector_t *sectorp)
286{
287 int i;
288 struct strip_zone *z = conf->strip_zone;
289 sector_t sector = *sectorp;
290
291 for (i = 0; i < conf->nr_strip_zones; i++)
292 if (sector < z[i].zone_end) {
293 if (i)
294 *sectorp = sector - z[i-1].zone_end;
295 return z + i;
296 }
297 BUG();
298}
299
300/*
301 * remaps the bio to the target device. we separate two flows.
302 * power 2 flow and a general flow for the sake of performance
303*/
304static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
305 sector_t sector, sector_t *sector_offset)
306{
307 unsigned int sect_in_chunk;
308 sector_t chunk;
309 struct r0conf *conf = mddev->private;
310 int raid_disks = conf->strip_zone[0].nb_dev;
311 unsigned int chunk_sects = mddev->chunk_sectors;
312
313 if (is_power_of_2(chunk_sects)) {
314 int chunksect_bits = ffz(~chunk_sects);
315 /* find the sector offset inside the chunk */
316 sect_in_chunk = sector & (chunk_sects - 1);
317 sector >>= chunksect_bits;
318 /* chunk in zone */
319 chunk = *sector_offset;
320 /* quotient is the chunk in real device*/
321 sector_div(chunk, zone->nb_dev << chunksect_bits);
322 } else{
323 sect_in_chunk = sector_div(sector, chunk_sects);
324 chunk = *sector_offset;
325 sector_div(chunk, chunk_sects * zone->nb_dev);
326 }
327 /*
328 * position the bio over the real device
329 * real sector = chunk in device + starting of zone
330 * + the position in the chunk
331 */
332 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
333 return conf->devlist[(zone - conf->strip_zone)*raid_disks
334 + sector_div(sector, zone->nb_dev)];
335}
336
337static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
338{
339 sector_t array_sectors = 0;
340 struct md_rdev *rdev;
341
342 WARN_ONCE(sectors || raid_disks,
343 "%s does not support generic reshape\n", __func__);
344
345 rdev_for_each(rdev, mddev)
346 array_sectors += (rdev->sectors &
347 ~(sector_t)(mddev->chunk_sectors-1));
348
349 return array_sectors;
350}
351
352static void raid0_free(struct mddev *mddev, void *priv);
353
354static int raid0_run(struct mddev *mddev)
355{
356 struct r0conf *conf;
357 int ret;
358
359 if (mddev->chunk_sectors == 0) {
360 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
361 mdname(mddev));
362 return -EINVAL;
363 }
364 if (md_check_no_bitmap(mddev))
365 return -EINVAL;
366
367 /* if private is not null, we are here after takeover */
368 if (mddev->private == NULL) {
369 ret = create_strip_zones(mddev, &conf);
370 if (ret < 0)
371 return ret;
372 mddev->private = conf;
373 }
374 conf = mddev->private;
375 if (mddev->queue) {
376 struct md_rdev *rdev;
377 bool discard_supported = false;
378
379 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
380 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
381 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);
382
383 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
384 blk_queue_io_opt(mddev->queue,
385 (mddev->chunk_sectors << 9) * mddev->raid_disks);
386
387 rdev_for_each(rdev, mddev) {
388 disk_stack_limits(mddev->gendisk, rdev->bdev,
389 rdev->data_offset << 9);
390 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
391 discard_supported = true;
392 }
393 if (!discard_supported)
394 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
395 else
396 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
397 }
398
399 /* calculate array device size */
400 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
401
402 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
403 mdname(mddev),
404 (unsigned long long)mddev->array_sectors);
405
406 if (mddev->queue) {
407 /* calculate the max read-ahead size.
408 * For read-ahead of large files to be effective, we need to
409 * readahead at least twice a whole stripe. i.e. number of devices
410 * multiplied by chunk size times 2.
411 * If an individual device has an ra_pages greater than the
412 * chunk size, then we will not drive that device as hard as it
413 * wants. We consider this a configuration error: a larger
414 * chunksize should be used in that case.
415 */
416 int stripe = mddev->raid_disks *
417 (mddev->chunk_sectors << 9) / PAGE_SIZE;
418 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
419 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
420 }
421
422 dump_zones(mddev);
423
424 ret = md_integrity_register(mddev);
425
426 return ret;
427}
428
429static void raid0_free(struct mddev *mddev, void *priv)
430{
431 struct r0conf *conf = priv;
432
433 kfree(conf->strip_zone);
434 kfree(conf->devlist);
435 kfree(conf);
436}
437
438/*
439 * Is io distribute over 1 or more chunks ?
440*/
441static inline int is_io_in_chunk_boundary(struct mddev *mddev,
442 unsigned int chunk_sects, struct bio *bio)
443{
444 if (likely(is_power_of_2(chunk_sects))) {
445 return chunk_sects >=
446 ((bio->bi_iter.bi_sector & (chunk_sects-1))
447 + bio_sectors(bio));
448 } else{
449 sector_t sector = bio->bi_iter.bi_sector;
450 return chunk_sects >= (sector_div(sector, chunk_sects)
451 + bio_sectors(bio));
452 }
453}
454
455static void raid0_make_request(struct mddev *mddev, struct bio *bio)
456{
457 struct strip_zone *zone;
458 struct md_rdev *tmp_dev;
459 struct bio *split;
460
461 if (unlikely(bio->bi_rw & REQ_FLUSH)) {
462 md_flush_request(mddev, bio);
463 return;
464 }
465
466 do {
467 sector_t sector = bio->bi_iter.bi_sector;
468 unsigned chunk_sects = mddev->chunk_sectors;
469
470 unsigned sectors = chunk_sects -
471 (likely(is_power_of_2(chunk_sects))
472 ? (sector & (chunk_sects-1))
473 : sector_div(sector, chunk_sects));
474
475 /* Restore due to sector_div */
476 sector = bio->bi_iter.bi_sector;
477
478 if (sectors < bio_sectors(bio)) {
479 split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
480 bio_chain(split, bio);
481 } else {
482 split = bio;
483 }
484
485 zone = find_zone(mddev->private, §or);
486 tmp_dev = map_sector(mddev, zone, sector, §or);
487 split->bi_bdev = tmp_dev->bdev;
488 split->bi_iter.bi_sector = sector + zone->dev_start +
489 tmp_dev->data_offset;
490
491 if (unlikely((split->bi_rw & REQ_DISCARD) &&
492 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
493 /* Just ignore it */
494 bio_endio(split);
495 } else
496 generic_make_request(split);
497 } while (split != bio);
498}
499
500static void raid0_status(struct seq_file *seq, struct mddev *mddev)
501{
502 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
503 return;
504}
505
506static void *raid0_takeover_raid45(struct mddev *mddev)
507{
508 struct md_rdev *rdev;
509 struct r0conf *priv_conf;
510
511 if (mddev->degraded != 1) {
512 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
513 mdname(mddev),
514 mddev->degraded);
515 return ERR_PTR(-EINVAL);
516 }
517
518 rdev_for_each(rdev, mddev) {
519 /* check slot number for a disk */
520 if (rdev->raid_disk == mddev->raid_disks-1) {
521 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
522 mdname(mddev));
523 return ERR_PTR(-EINVAL);
524 }
525 rdev->sectors = mddev->dev_sectors;
526 }
527
528 /* Set new parameters */
529 mddev->new_level = 0;
530 mddev->new_layout = 0;
531 mddev->new_chunk_sectors = mddev->chunk_sectors;
532 mddev->raid_disks--;
533 mddev->delta_disks = -1;
534 /* make sure it will be not marked as dirty */
535 mddev->recovery_cp = MaxSector;
536
537 create_strip_zones(mddev, &priv_conf);
538 return priv_conf;
539}
540
541static void *raid0_takeover_raid10(struct mddev *mddev)
542{
543 struct r0conf *priv_conf;
544
545 /* Check layout:
546 * - far_copies must be 1
547 * - near_copies must be 2
548 * - disks number must be even
549 * - all mirrors must be already degraded
550 */
551 if (mddev->layout != ((1 << 8) + 2)) {
552 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
553 mdname(mddev),
554 mddev->layout);
555 return ERR_PTR(-EINVAL);
556 }
557 if (mddev->raid_disks & 1) {
558 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
559 mdname(mddev));
560 return ERR_PTR(-EINVAL);
561 }
562 if (mddev->degraded != (mddev->raid_disks>>1)) {
563 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n",
564 mdname(mddev));
565 return ERR_PTR(-EINVAL);
566 }
567
568 /* Set new parameters */
569 mddev->new_level = 0;
570 mddev->new_layout = 0;
571 mddev->new_chunk_sectors = mddev->chunk_sectors;
572 mddev->delta_disks = - mddev->raid_disks / 2;
573 mddev->raid_disks += mddev->delta_disks;
574 mddev->degraded = 0;
575 /* make sure it will be not marked as dirty */
576 mddev->recovery_cp = MaxSector;
577
578 create_strip_zones(mddev, &priv_conf);
579 return priv_conf;
580}
581
582static void *raid0_takeover_raid1(struct mddev *mddev)
583{
584 struct r0conf *priv_conf;
585 int chunksect;
586
587 /* Check layout:
588 * - (N - 1) mirror drives must be already faulty
589 */
590 if ((mddev->raid_disks - 1) != mddev->degraded) {
591 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
592 mdname(mddev));
593 return ERR_PTR(-EINVAL);
594 }
595
596 /*
597 * a raid1 doesn't have the notion of chunk size, so
598 * figure out the largest suitable size we can use.
599 */
600 chunksect = 64 * 2; /* 64K by default */
601
602 /* The array must be an exact multiple of chunksize */
603 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
604 chunksect >>= 1;
605
606 if ((chunksect << 9) < PAGE_SIZE)
607 /* array size does not allow a suitable chunk size */
608 return ERR_PTR(-EINVAL);
609
610 /* Set new parameters */
611 mddev->new_level = 0;
612 mddev->new_layout = 0;
613 mddev->new_chunk_sectors = chunksect;
614 mddev->chunk_sectors = chunksect;
615 mddev->delta_disks = 1 - mddev->raid_disks;
616 mddev->raid_disks = 1;
617 /* make sure it will be not marked as dirty */
618 mddev->recovery_cp = MaxSector;
619
620 create_strip_zones(mddev, &priv_conf);
621 return priv_conf;
622}
623
624static void *raid0_takeover(struct mddev *mddev)
625{
626 /* raid0 can take over:
627 * raid4 - if all data disks are active.
628 * raid5 - providing it is Raid4 layout and one disk is faulty
629 * raid10 - assuming we have all necessary active disks
630 * raid1 - with (N -1) mirror drives faulty
631 */
632
633 if (mddev->bitmap) {
634 printk(KERN_ERR "md/raid0: %s: cannot takeover array with bitmap\n",
635 mdname(mddev));
636 return ERR_PTR(-EBUSY);
637 }
638 if (mddev->level == 4)
639 return raid0_takeover_raid45(mddev);
640
641 if (mddev->level == 5) {
642 if (mddev->layout == ALGORITHM_PARITY_N)
643 return raid0_takeover_raid45(mddev);
644
645 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
646 mdname(mddev), ALGORITHM_PARITY_N);
647 }
648
649 if (mddev->level == 10)
650 return raid0_takeover_raid10(mddev);
651
652 if (mddev->level == 1)
653 return raid0_takeover_raid1(mddev);
654
655 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n",
656 mddev->level);
657
658 return ERR_PTR(-EINVAL);
659}
660
661static void raid0_quiesce(struct mddev *mddev, int state)
662{
663}
664
665static struct md_personality raid0_personality=
666{
667 .name = "raid0",
668 .level = 0,
669 .owner = THIS_MODULE,
670 .make_request = raid0_make_request,
671 .run = raid0_run,
672 .free = raid0_free,
673 .status = raid0_status,
674 .size = raid0_size,
675 .takeover = raid0_takeover,
676 .quiesce = raid0_quiesce,
677 .congested = raid0_congested,
678};
679
680static int __init raid0_init (void)
681{
682 return register_md_personality (&raid0_personality);
683}
684
685static void raid0_exit (void)
686{
687 unregister_md_personality (&raid0_personality);
688}
689
690module_init(raid0_init);
691module_exit(raid0_exit);
692MODULE_LICENSE("GPL");
693MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
694MODULE_ALIAS("md-personality-2"); /* RAID0 */
695MODULE_ALIAS("md-raid0");
696MODULE_ALIAS("md-level-0");