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
22 static int default_layout = 0;
23 module_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 */
dump_zones(struct mddev * mddev)35 static void dump_zones(struct mddev *mddev)
36 {
37 int j, k;
38 sector_t zone_size = 0;
39 sector_t zone_start = 0;
40 char b[BDEVNAME_SIZE];
41 struct r0conf *conf = mddev->private;
42 int raid_disks = conf->strip_zone[0].nb_dev;
43 pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
44 mdname(mddev),
45 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
46 for (j = 0; j < conf->nr_strip_zones; j++) {
47 char line[200];
48 int len = 0;
49
50 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
51 len += scnprintf(line+len, 200-len, "%s%s", k?"/":"",
52 bdevname(conf->devlist[j*raid_disks
53 + k]->bdev, b));
54 pr_debug("md: zone%d=[%s]\n", j, line);
55
56 zone_size = conf->strip_zone[j].zone_end - zone_start;
57 pr_debug(" zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n",
58 (unsigned long long)zone_start>>1,
59 (unsigned long long)conf->strip_zone[j].dev_start>>1,
60 (unsigned long long)zone_size>>1);
61 zone_start = conf->strip_zone[j].zone_end;
62 }
63 }
64
create_strip_zones(struct mddev * mddev,struct r0conf ** private_conf)65 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
66 {
67 int i, c, err;
68 sector_t curr_zone_end, sectors;
69 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
70 struct strip_zone *zone;
71 int cnt;
72 char b[BDEVNAME_SIZE];
73 char b2[BDEVNAME_SIZE];
74 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
75 unsigned blksize = 512;
76
77 *private_conf = ERR_PTR(-ENOMEM);
78 if (!conf)
79 return -ENOMEM;
80 rdev_for_each(rdev1, mddev) {
81 pr_debug("md/raid0:%s: looking at %s\n",
82 mdname(mddev),
83 bdevname(rdev1->bdev, b));
84 c = 0;
85
86 /* round size to chunk_size */
87 sectors = rdev1->sectors;
88 sector_div(sectors, mddev->chunk_sectors);
89 rdev1->sectors = sectors * mddev->chunk_sectors;
90
91 blksize = max(blksize, queue_logical_block_size(
92 rdev1->bdev->bd_disk->queue));
93
94 rdev_for_each(rdev2, mddev) {
95 pr_debug("md/raid0:%s: comparing %s(%llu)"
96 " with %s(%llu)\n",
97 mdname(mddev),
98 bdevname(rdev1->bdev,b),
99 (unsigned long long)rdev1->sectors,
100 bdevname(rdev2->bdev,b2),
101 (unsigned long long)rdev2->sectors);
102 if (rdev2 == rdev1) {
103 pr_debug("md/raid0:%s: END\n",
104 mdname(mddev));
105 break;
106 }
107 if (rdev2->sectors == rdev1->sectors) {
108 /*
109 * Not unique, don't count it as a new
110 * group
111 */
112 pr_debug("md/raid0:%s: EQUAL\n",
113 mdname(mddev));
114 c = 1;
115 break;
116 }
117 pr_debug("md/raid0:%s: NOT EQUAL\n",
118 mdname(mddev));
119 }
120 if (!c) {
121 pr_debug("md/raid0:%s: ==> UNIQUE\n",
122 mdname(mddev));
123 conf->nr_strip_zones++;
124 pr_debug("md/raid0:%s: %d zones\n",
125 mdname(mddev), conf->nr_strip_zones);
126 }
127 }
128 pr_debug("md/raid0:%s: FINAL %d zones\n",
129 mdname(mddev), conf->nr_strip_zones);
130
131 /*
132 * now since we have the hard sector sizes, we can make sure
133 * chunk size is a multiple of that sector size
134 */
135 if ((mddev->chunk_sectors << 9) % blksize) {
136 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
137 mdname(mddev),
138 mddev->chunk_sectors << 9, blksize);
139 err = -EINVAL;
140 goto abort;
141 }
142
143 err = -ENOMEM;
144 conf->strip_zone = kcalloc(conf->nr_strip_zones,
145 sizeof(struct strip_zone),
146 GFP_KERNEL);
147 if (!conf->strip_zone)
148 goto abort;
149 conf->devlist = kzalloc(array3_size(sizeof(struct md_rdev *),
150 conf->nr_strip_zones,
151 mddev->raid_disks),
152 GFP_KERNEL);
153 if (!conf->devlist)
154 goto abort;
155
156 /* The first zone must contain all devices, so here we check that
157 * there is a proper alignment of slots to devices and find them all
158 */
159 zone = &conf->strip_zone[0];
160 cnt = 0;
161 smallest = NULL;
162 dev = conf->devlist;
163 err = -EINVAL;
164 rdev_for_each(rdev1, mddev) {
165 int j = rdev1->raid_disk;
166
167 if (mddev->level == 10) {
168 /* taking over a raid10-n2 array */
169 j /= 2;
170 rdev1->new_raid_disk = j;
171 }
172
173 if (mddev->level == 1) {
174 /* taiking over a raid1 array-
175 * we have only one active disk
176 */
177 j = 0;
178 rdev1->new_raid_disk = j;
179 }
180
181 if (j < 0) {
182 pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
183 mdname(mddev));
184 goto abort;
185 }
186 if (j >= mddev->raid_disks) {
187 pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
188 mdname(mddev), j);
189 goto abort;
190 }
191 if (dev[j]) {
192 pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
193 mdname(mddev), j);
194 goto abort;
195 }
196 dev[j] = rdev1;
197
198 if (!smallest || (rdev1->sectors < smallest->sectors))
199 smallest = rdev1;
200 cnt++;
201 }
202 if (cnt != mddev->raid_disks) {
203 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
204 mdname(mddev), cnt, mddev->raid_disks);
205 goto abort;
206 }
207 zone->nb_dev = cnt;
208 zone->zone_end = smallest->sectors * cnt;
209
210 curr_zone_end = zone->zone_end;
211
212 /* now do the other zones */
213 for (i = 1; i < conf->nr_strip_zones; i++)
214 {
215 int j;
216
217 zone = conf->strip_zone + i;
218 dev = conf->devlist + i * mddev->raid_disks;
219
220 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
221 zone->dev_start = smallest->sectors;
222 smallest = NULL;
223 c = 0;
224
225 for (j=0; j<cnt; j++) {
226 rdev = conf->devlist[j];
227 if (rdev->sectors <= zone->dev_start) {
228 pr_debug("md/raid0:%s: checking %s ... nope\n",
229 mdname(mddev),
230 bdevname(rdev->bdev, b));
231 continue;
232 }
233 pr_debug("md/raid0:%s: checking %s ..."
234 " contained as device %d\n",
235 mdname(mddev),
236 bdevname(rdev->bdev, b), c);
237 dev[c] = rdev;
238 c++;
239 if (!smallest || rdev->sectors < smallest->sectors) {
240 smallest = rdev;
241 pr_debug("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 pr_debug("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 pr_debug("md/raid0:%s: current zone start: %llu\n",
257 mdname(mddev),
258 (unsigned long long)smallest->sectors);
259 }
260
261 if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) {
262 conf->layout = RAID0_ORIG_LAYOUT;
263 } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
264 mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
265 conf->layout = mddev->layout;
266 } else if (default_layout == RAID0_ORIG_LAYOUT ||
267 default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
268 conf->layout = default_layout;
269 } else {
270 pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
271 mdname(mddev));
272 pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
273 err = -EOPNOTSUPP;
274 goto abort;
275 }
276
277 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
278 *private_conf = conf;
279
280 return 0;
281 abort:
282 kfree(conf->strip_zone);
283 kfree(conf->devlist);
284 kfree(conf);
285 *private_conf = ERR_PTR(err);
286 return err;
287 }
288
289 /* Find the zone which holds a particular offset
290 * Update *sectorp to be an offset in that zone
291 */
find_zone(struct r0conf * conf,sector_t * sectorp)292 static struct strip_zone *find_zone(struct r0conf *conf,
293 sector_t *sectorp)
294 {
295 int i;
296 struct strip_zone *z = conf->strip_zone;
297 sector_t sector = *sectorp;
298
299 for (i = 0; i < conf->nr_strip_zones; i++)
300 if (sector < z[i].zone_end) {
301 if (i)
302 *sectorp = sector - z[i-1].zone_end;
303 return z + i;
304 }
305 BUG();
306 }
307
308 /*
309 * remaps the bio to the target device. we separate two flows.
310 * power 2 flow and a general flow for the sake of performance
311 */
map_sector(struct mddev * mddev,struct strip_zone * zone,sector_t sector,sector_t * sector_offset)312 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
313 sector_t sector, sector_t *sector_offset)
314 {
315 unsigned int sect_in_chunk;
316 sector_t chunk;
317 struct r0conf *conf = mddev->private;
318 int raid_disks = conf->strip_zone[0].nb_dev;
319 unsigned int chunk_sects = mddev->chunk_sectors;
320
321 if (is_power_of_2(chunk_sects)) {
322 int chunksect_bits = ffz(~chunk_sects);
323 /* find the sector offset inside the chunk */
324 sect_in_chunk = sector & (chunk_sects - 1);
325 sector >>= chunksect_bits;
326 /* chunk in zone */
327 chunk = *sector_offset;
328 /* quotient is the chunk in real device*/
329 sector_div(chunk, zone->nb_dev << chunksect_bits);
330 } else{
331 sect_in_chunk = sector_div(sector, chunk_sects);
332 chunk = *sector_offset;
333 sector_div(chunk, chunk_sects * zone->nb_dev);
334 }
335 /*
336 * position the bio over the real device
337 * real sector = chunk in device + starting of zone
338 * + the position in the chunk
339 */
340 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
341 return conf->devlist[(zone - conf->strip_zone)*raid_disks
342 + sector_div(sector, zone->nb_dev)];
343 }
344
raid0_size(struct mddev * mddev,sector_t sectors,int raid_disks)345 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
346 {
347 sector_t array_sectors = 0;
348 struct md_rdev *rdev;
349
350 WARN_ONCE(sectors || raid_disks,
351 "%s does not support generic reshape\n", __func__);
352
353 rdev_for_each(rdev, mddev)
354 array_sectors += (rdev->sectors &
355 ~(sector_t)(mddev->chunk_sectors-1));
356
357 return array_sectors;
358 }
359
360 static void raid0_free(struct mddev *mddev, void *priv);
361
raid0_run(struct mddev * mddev)362 static int raid0_run(struct mddev *mddev)
363 {
364 struct r0conf *conf;
365 int ret;
366
367 if (mddev->chunk_sectors == 0) {
368 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
369 return -EINVAL;
370 }
371 if (md_check_no_bitmap(mddev))
372 return -EINVAL;
373
374 /* if private is not null, we are here after takeover */
375 if (mddev->private == NULL) {
376 ret = create_strip_zones(mddev, &conf);
377 if (ret < 0)
378 return ret;
379 mddev->private = conf;
380 }
381 conf = mddev->private;
382 if (mddev->queue) {
383 struct md_rdev *rdev;
384 bool discard_supported = false;
385
386 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
387 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
388 blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors);
389 blk_queue_max_discard_sectors(mddev->queue, UINT_MAX);
390
391 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
392 blk_queue_io_opt(mddev->queue,
393 (mddev->chunk_sectors << 9) * mddev->raid_disks);
394
395 rdev_for_each(rdev, mddev) {
396 disk_stack_limits(mddev->gendisk, rdev->bdev,
397 rdev->data_offset << 9);
398 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
399 discard_supported = true;
400 }
401 if (!discard_supported)
402 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, mddev->queue);
403 else
404 blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
405 }
406
407 /* calculate array device size */
408 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
409
410 pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
411 mdname(mddev),
412 (unsigned long long)mddev->array_sectors);
413
414 dump_zones(mddev);
415
416 ret = md_integrity_register(mddev);
417
418 return ret;
419 }
420
raid0_free(struct mddev * mddev,void * priv)421 static void raid0_free(struct mddev *mddev, void *priv)
422 {
423 struct r0conf *conf = priv;
424
425 kfree(conf->strip_zone);
426 kfree(conf->devlist);
427 kfree(conf);
428 }
429
raid0_handle_discard(struct mddev * mddev,struct bio * bio)430 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
431 {
432 struct r0conf *conf = mddev->private;
433 struct strip_zone *zone;
434 sector_t start = bio->bi_iter.bi_sector;
435 sector_t end;
436 unsigned int stripe_size;
437 sector_t first_stripe_index, last_stripe_index;
438 sector_t start_disk_offset;
439 unsigned int start_disk_index;
440 sector_t end_disk_offset;
441 unsigned int end_disk_index;
442 unsigned int disk;
443
444 zone = find_zone(conf, &start);
445
446 if (bio_end_sector(bio) > zone->zone_end) {
447 struct bio *split = bio_split(bio,
448 zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO,
449 &mddev->bio_set);
450 bio_chain(split, bio);
451 submit_bio_noacct(bio);
452 bio = split;
453 end = zone->zone_end;
454 } else
455 end = bio_end_sector(bio);
456
457 if (zone != conf->strip_zone)
458 end = end - zone[-1].zone_end;
459
460 /* Now start and end is the offset in zone */
461 stripe_size = zone->nb_dev * mddev->chunk_sectors;
462
463 first_stripe_index = start;
464 sector_div(first_stripe_index, stripe_size);
465 last_stripe_index = end;
466 sector_div(last_stripe_index, stripe_size);
467
468 start_disk_index = (int)(start - first_stripe_index * stripe_size) /
469 mddev->chunk_sectors;
470 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
471 mddev->chunk_sectors) +
472 first_stripe_index * mddev->chunk_sectors;
473 end_disk_index = (int)(end - last_stripe_index * stripe_size) /
474 mddev->chunk_sectors;
475 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
476 mddev->chunk_sectors) +
477 last_stripe_index * mddev->chunk_sectors;
478
479 for (disk = 0; disk < zone->nb_dev; disk++) {
480 sector_t dev_start, dev_end;
481 struct bio *discard_bio = NULL;
482 struct md_rdev *rdev;
483
484 if (disk < start_disk_index)
485 dev_start = (first_stripe_index + 1) *
486 mddev->chunk_sectors;
487 else if (disk > start_disk_index)
488 dev_start = first_stripe_index * mddev->chunk_sectors;
489 else
490 dev_start = start_disk_offset;
491
492 if (disk < end_disk_index)
493 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
494 else if (disk > end_disk_index)
495 dev_end = last_stripe_index * mddev->chunk_sectors;
496 else
497 dev_end = end_disk_offset;
498
499 if (dev_end <= dev_start)
500 continue;
501
502 rdev = conf->devlist[(zone - conf->strip_zone) *
503 conf->strip_zone[0].nb_dev + disk];
504 if (__blkdev_issue_discard(rdev->bdev,
505 dev_start + zone->dev_start + rdev->data_offset,
506 dev_end - dev_start, GFP_NOIO, 0, &discard_bio) ||
507 !discard_bio)
508 continue;
509 bio_chain(discard_bio, bio);
510 bio_clone_blkg_association(discard_bio, bio);
511 if (mddev->gendisk)
512 trace_block_bio_remap(bdev_get_queue(rdev->bdev),
513 discard_bio, disk_devt(mddev->gendisk),
514 bio->bi_iter.bi_sector);
515 submit_bio_noacct(discard_bio);
516 }
517 bio_endio(bio);
518 }
519
raid0_make_request(struct mddev * mddev,struct bio * bio)520 static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
521 {
522 struct r0conf *conf = mddev->private;
523 struct strip_zone *zone;
524 struct md_rdev *tmp_dev;
525 sector_t bio_sector;
526 sector_t sector;
527 sector_t orig_sector;
528 unsigned chunk_sects;
529 unsigned sectors;
530
531 if (unlikely(bio->bi_opf & REQ_PREFLUSH)
532 && md_flush_request(mddev, bio))
533 return true;
534
535 if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
536 raid0_handle_discard(mddev, bio);
537 return true;
538 }
539
540 bio_sector = bio->bi_iter.bi_sector;
541 sector = bio_sector;
542 chunk_sects = mddev->chunk_sectors;
543
544 sectors = chunk_sects -
545 (likely(is_power_of_2(chunk_sects))
546 ? (sector & (chunk_sects-1))
547 : sector_div(sector, chunk_sects));
548
549 /* Restore due to sector_div */
550 sector = bio_sector;
551
552 if (sectors < bio_sectors(bio)) {
553 struct bio *split = bio_split(bio, sectors, GFP_NOIO,
554 &mddev->bio_set);
555 bio_chain(split, bio);
556 submit_bio_noacct(bio);
557 bio = split;
558 }
559
560 orig_sector = sector;
561 zone = find_zone(mddev->private, §or);
562 switch (conf->layout) {
563 case RAID0_ORIG_LAYOUT:
564 tmp_dev = map_sector(mddev, zone, orig_sector, §or);
565 break;
566 case RAID0_ALT_MULTIZONE_LAYOUT:
567 tmp_dev = map_sector(mddev, zone, sector, §or);
568 break;
569 default:
570 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
571 bio_io_error(bio);
572 return true;
573 }
574
575 if (unlikely(is_mddev_broken(tmp_dev, "raid0"))) {
576 bio_io_error(bio);
577 return true;
578 }
579
580 bio_set_dev(bio, tmp_dev->bdev);
581 bio->bi_iter.bi_sector = sector + zone->dev_start +
582 tmp_dev->data_offset;
583
584 if (mddev->gendisk)
585 trace_block_bio_remap(bio->bi_disk->queue, bio,
586 disk_devt(mddev->gendisk), bio_sector);
587 mddev_check_writesame(mddev, bio);
588 mddev_check_write_zeroes(mddev, bio);
589 submit_bio_noacct(bio);
590 return true;
591 }
592
raid0_status(struct seq_file * seq,struct mddev * mddev)593 static void raid0_status(struct seq_file *seq, struct mddev *mddev)
594 {
595 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
596 return;
597 }
598
raid0_takeover_raid45(struct mddev * mddev)599 static void *raid0_takeover_raid45(struct mddev *mddev)
600 {
601 struct md_rdev *rdev;
602 struct r0conf *priv_conf;
603
604 if (mddev->degraded != 1) {
605 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
606 mdname(mddev),
607 mddev->degraded);
608 return ERR_PTR(-EINVAL);
609 }
610
611 rdev_for_each(rdev, mddev) {
612 /* check slot number for a disk */
613 if (rdev->raid_disk == mddev->raid_disks-1) {
614 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
615 mdname(mddev));
616 return ERR_PTR(-EINVAL);
617 }
618 rdev->sectors = mddev->dev_sectors;
619 }
620
621 /* Set new parameters */
622 mddev->new_level = 0;
623 mddev->new_layout = 0;
624 mddev->new_chunk_sectors = mddev->chunk_sectors;
625 mddev->raid_disks--;
626 mddev->delta_disks = -1;
627 /* make sure it will be not marked as dirty */
628 mddev->recovery_cp = MaxSector;
629 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
630
631 create_strip_zones(mddev, &priv_conf);
632
633 return priv_conf;
634 }
635
raid0_takeover_raid10(struct mddev * mddev)636 static void *raid0_takeover_raid10(struct mddev *mddev)
637 {
638 struct r0conf *priv_conf;
639
640 /* Check layout:
641 * - far_copies must be 1
642 * - near_copies must be 2
643 * - disks number must be even
644 * - all mirrors must be already degraded
645 */
646 if (mddev->layout != ((1 << 8) + 2)) {
647 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
648 mdname(mddev),
649 mddev->layout);
650 return ERR_PTR(-EINVAL);
651 }
652 if (mddev->raid_disks & 1) {
653 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
654 mdname(mddev));
655 return ERR_PTR(-EINVAL);
656 }
657 if (mddev->degraded != (mddev->raid_disks>>1)) {
658 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
659 mdname(mddev));
660 return ERR_PTR(-EINVAL);
661 }
662
663 /* Set new parameters */
664 mddev->new_level = 0;
665 mddev->new_layout = 0;
666 mddev->new_chunk_sectors = mddev->chunk_sectors;
667 mddev->delta_disks = - mddev->raid_disks / 2;
668 mddev->raid_disks += mddev->delta_disks;
669 mddev->degraded = 0;
670 /* make sure it will be not marked as dirty */
671 mddev->recovery_cp = MaxSector;
672 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
673
674 create_strip_zones(mddev, &priv_conf);
675 return priv_conf;
676 }
677
raid0_takeover_raid1(struct mddev * mddev)678 static void *raid0_takeover_raid1(struct mddev *mddev)
679 {
680 struct r0conf *priv_conf;
681 int chunksect;
682
683 /* Check layout:
684 * - (N - 1) mirror drives must be already faulty
685 */
686 if ((mddev->raid_disks - 1) != mddev->degraded) {
687 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
688 mdname(mddev));
689 return ERR_PTR(-EINVAL);
690 }
691
692 /*
693 * a raid1 doesn't have the notion of chunk size, so
694 * figure out the largest suitable size we can use.
695 */
696 chunksect = 64 * 2; /* 64K by default */
697
698 /* The array must be an exact multiple of chunksize */
699 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
700 chunksect >>= 1;
701
702 if ((chunksect << 9) < PAGE_SIZE)
703 /* array size does not allow a suitable chunk size */
704 return ERR_PTR(-EINVAL);
705
706 /* Set new parameters */
707 mddev->new_level = 0;
708 mddev->new_layout = 0;
709 mddev->new_chunk_sectors = chunksect;
710 mddev->chunk_sectors = chunksect;
711 mddev->delta_disks = 1 - mddev->raid_disks;
712 mddev->raid_disks = 1;
713 /* make sure it will be not marked as dirty */
714 mddev->recovery_cp = MaxSector;
715 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
716
717 create_strip_zones(mddev, &priv_conf);
718 return priv_conf;
719 }
720
raid0_takeover(struct mddev * mddev)721 static void *raid0_takeover(struct mddev *mddev)
722 {
723 /* raid0 can take over:
724 * raid4 - if all data disks are active.
725 * raid5 - providing it is Raid4 layout and one disk is faulty
726 * raid10 - assuming we have all necessary active disks
727 * raid1 - with (N -1) mirror drives faulty
728 */
729
730 if (mddev->bitmap) {
731 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
732 mdname(mddev));
733 return ERR_PTR(-EBUSY);
734 }
735 if (mddev->level == 4)
736 return raid0_takeover_raid45(mddev);
737
738 if (mddev->level == 5) {
739 if (mddev->layout == ALGORITHM_PARITY_N)
740 return raid0_takeover_raid45(mddev);
741
742 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
743 mdname(mddev), ALGORITHM_PARITY_N);
744 }
745
746 if (mddev->level == 10)
747 return raid0_takeover_raid10(mddev);
748
749 if (mddev->level == 1)
750 return raid0_takeover_raid1(mddev);
751
752 pr_warn("Takeover from raid%i to raid0 not supported\n",
753 mddev->level);
754
755 return ERR_PTR(-EINVAL);
756 }
757
raid0_quiesce(struct mddev * mddev,int quiesce)758 static void raid0_quiesce(struct mddev *mddev, int quiesce)
759 {
760 }
761
762 static struct md_personality raid0_personality=
763 {
764 .name = "raid0",
765 .level = 0,
766 .owner = THIS_MODULE,
767 .make_request = raid0_make_request,
768 .run = raid0_run,
769 .free = raid0_free,
770 .status = raid0_status,
771 .size = raid0_size,
772 .takeover = raid0_takeover,
773 .quiesce = raid0_quiesce,
774 };
775
raid0_init(void)776 static int __init raid0_init (void)
777 {
778 return register_md_personality (&raid0_personality);
779 }
780
raid0_exit(void)781 static void raid0_exit (void)
782 {
783 unregister_md_personality (&raid0_personality);
784 }
785
786 module_init(raid0_init);
787 module_exit(raid0_exit);
788 MODULE_LICENSE("GPL");
789 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
790 MODULE_ALIAS("md-personality-2"); /* RAID0 */
791 MODULE_ALIAS("md-raid0");
792 MODULE_ALIAS("md-level-0");
793