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 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
create_strip_zones(struct mddev * mddev,struct r0conf ** private_conf)63 static 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 if (conf->layout == RAID0_ORIG_LAYOUT) {
274 for (i = 1; i < conf->nr_strip_zones; i++) {
275 sector_t first_sector = conf->strip_zone[i-1].zone_end;
276
277 sector_div(first_sector, mddev->chunk_sectors);
278 zone = conf->strip_zone + i;
279 /* disk_shift is first disk index used in the zone */
280 zone->disk_shift = sector_div(first_sector,
281 zone->nb_dev);
282 }
283 }
284
285 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
286 *private_conf = conf;
287
288 return 0;
289 abort:
290 kfree(conf->strip_zone);
291 kfree(conf->devlist);
292 kfree(conf);
293 *private_conf = ERR_PTR(err);
294 return err;
295 }
296
297 /* Find the zone which holds a particular offset
298 * Update *sectorp to be an offset in that zone
299 */
find_zone(struct r0conf * conf,sector_t * sectorp)300 static struct strip_zone *find_zone(struct r0conf *conf,
301 sector_t *sectorp)
302 {
303 int i;
304 struct strip_zone *z = conf->strip_zone;
305 sector_t sector = *sectorp;
306
307 for (i = 0; i < conf->nr_strip_zones; i++)
308 if (sector < z[i].zone_end) {
309 if (i)
310 *sectorp = sector - z[i-1].zone_end;
311 return z + i;
312 }
313 BUG();
314 }
315
316 /*
317 * remaps the bio to the target device. we separate two flows.
318 * power 2 flow and a general flow for the sake of performance
319 */
map_sector(struct mddev * mddev,struct strip_zone * zone,sector_t sector,sector_t * sector_offset)320 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
321 sector_t sector, sector_t *sector_offset)
322 {
323 unsigned int sect_in_chunk;
324 sector_t chunk;
325 struct r0conf *conf = mddev->private;
326 int raid_disks = conf->strip_zone[0].nb_dev;
327 unsigned int chunk_sects = mddev->chunk_sectors;
328
329 if (is_power_of_2(chunk_sects)) {
330 int chunksect_bits = ffz(~chunk_sects);
331 /* find the sector offset inside the chunk */
332 sect_in_chunk = sector & (chunk_sects - 1);
333 sector >>= chunksect_bits;
334 /* chunk in zone */
335 chunk = *sector_offset;
336 /* quotient is the chunk in real device*/
337 sector_div(chunk, zone->nb_dev << chunksect_bits);
338 } else{
339 sect_in_chunk = sector_div(sector, chunk_sects);
340 chunk = *sector_offset;
341 sector_div(chunk, chunk_sects * zone->nb_dev);
342 }
343 /*
344 * position the bio over the real device
345 * real sector = chunk in device + starting of zone
346 * + the position in the chunk
347 */
348 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
349 return conf->devlist[(zone - conf->strip_zone)*raid_disks
350 + sector_div(sector, zone->nb_dev)];
351 }
352
raid0_size(struct mddev * mddev,sector_t sectors,int raid_disks)353 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
354 {
355 sector_t array_sectors = 0;
356 struct md_rdev *rdev;
357
358 WARN_ONCE(sectors || raid_disks,
359 "%s does not support generic reshape\n", __func__);
360
361 rdev_for_each(rdev, mddev)
362 array_sectors += (rdev->sectors &
363 ~(sector_t)(mddev->chunk_sectors-1));
364
365 return array_sectors;
366 }
367
raid0_free(struct mddev * mddev,void * priv)368 static void raid0_free(struct mddev *mddev, void *priv)
369 {
370 struct r0conf *conf = priv;
371
372 kfree(conf->strip_zone);
373 kfree(conf->devlist);
374 kfree(conf);
375 }
376
raid0_set_limits(struct mddev * mddev)377 static int raid0_set_limits(struct mddev *mddev)
378 {
379 struct queue_limits lim;
380 int err;
381
382 md_init_stacking_limits(&lim);
383 lim.max_hw_sectors = mddev->chunk_sectors;
384 lim.max_write_zeroes_sectors = mddev->chunk_sectors;
385 lim.io_min = mddev->chunk_sectors << 9;
386 lim.io_opt = lim.io_min * mddev->raid_disks;
387 lim.features |= BLK_FEAT_ATOMIC_WRITES_STACKED;
388 err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
389 if (err) {
390 queue_limits_cancel_update(mddev->gendisk->queue);
391 return err;
392 }
393 return queue_limits_set(mddev->gendisk->queue, &lim);
394 }
395
raid0_run(struct mddev * mddev)396 static int raid0_run(struct mddev *mddev)
397 {
398 struct r0conf *conf;
399 int ret;
400
401 if (mddev->chunk_sectors == 0) {
402 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
403 return -EINVAL;
404 }
405 if (md_check_no_bitmap(mddev))
406 return -EINVAL;
407
408 /* if private is not null, we are here after takeover */
409 if (mddev->private == NULL) {
410 ret = create_strip_zones(mddev, &conf);
411 if (ret < 0)
412 return ret;
413 mddev->private = conf;
414 }
415 conf = mddev->private;
416 if (!mddev_is_dm(mddev)) {
417 ret = raid0_set_limits(mddev);
418 if (ret)
419 return ret;
420 }
421
422 /* calculate array device size */
423 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
424
425 pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
426 mdname(mddev),
427 (unsigned long long)mddev->array_sectors);
428
429 dump_zones(mddev);
430
431 return md_integrity_register(mddev);
432 }
433
434 /*
435 * Convert disk_index to the disk order in which it is read/written.
436 * For example, if we have 4 disks, they are numbered 0,1,2,3. If we
437 * write the disks starting at disk 3, then the read/write order would
438 * be disk 3, then 0, then 1, and then disk 2 and we want map_disk_shift()
439 * to map the disks as follows 0,1,2,3 => 1,2,3,0. So disk 0 would map
440 * to 1, 1 to 2, 2 to 3, and 3 to 0. That way we can compare disks in
441 * that 'output' space to understand the read/write disk ordering.
442 */
map_disk_shift(int disk_index,int num_disks,int disk_shift)443 static int map_disk_shift(int disk_index, int num_disks, int disk_shift)
444 {
445 return ((disk_index + num_disks - disk_shift) % num_disks);
446 }
447
raid0_handle_discard(struct mddev * mddev,struct bio * bio)448 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
449 {
450 struct r0conf *conf = mddev->private;
451 struct strip_zone *zone;
452 sector_t start = bio->bi_iter.bi_sector;
453 sector_t end;
454 unsigned int stripe_size;
455 sector_t first_stripe_index, last_stripe_index;
456 sector_t start_disk_offset;
457 unsigned int start_disk_index;
458 sector_t end_disk_offset;
459 unsigned int end_disk_index;
460 unsigned int disk;
461 sector_t orig_start, orig_end;
462
463 orig_start = start;
464 zone = find_zone(conf, &start);
465
466 if (bio_end_sector(bio) > zone->zone_end) {
467 struct bio *split = bio_split(bio,
468 zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO,
469 &mddev->bio_set);
470
471 if (IS_ERR(split)) {
472 bio->bi_status = errno_to_blk_status(PTR_ERR(split));
473 bio_endio(bio);
474 return;
475 }
476 bio_chain(split, bio);
477 submit_bio_noacct(bio);
478 bio = split;
479 end = zone->zone_end;
480 } else
481 end = bio_end_sector(bio);
482
483 orig_end = end;
484 if (zone != conf->strip_zone)
485 end = end - zone[-1].zone_end;
486
487 /* Now start and end is the offset in zone */
488 stripe_size = zone->nb_dev * mddev->chunk_sectors;
489
490 first_stripe_index = start;
491 sector_div(first_stripe_index, stripe_size);
492 last_stripe_index = end;
493 sector_div(last_stripe_index, stripe_size);
494
495 /* In the first zone the original and alternate layouts are the same */
496 if ((conf->layout == RAID0_ORIG_LAYOUT) && (zone != conf->strip_zone)) {
497 sector_div(orig_start, mddev->chunk_sectors);
498 start_disk_index = sector_div(orig_start, zone->nb_dev);
499 start_disk_index = map_disk_shift(start_disk_index,
500 zone->nb_dev,
501 zone->disk_shift);
502 sector_div(orig_end, mddev->chunk_sectors);
503 end_disk_index = sector_div(orig_end, zone->nb_dev);
504 end_disk_index = map_disk_shift(end_disk_index,
505 zone->nb_dev, zone->disk_shift);
506 } else {
507 start_disk_index = (int)(start - first_stripe_index * stripe_size) /
508 mddev->chunk_sectors;
509 end_disk_index = (int)(end - last_stripe_index * stripe_size) /
510 mddev->chunk_sectors;
511 }
512 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
513 mddev->chunk_sectors) +
514 first_stripe_index * mddev->chunk_sectors;
515 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
516 mddev->chunk_sectors) +
517 last_stripe_index * mddev->chunk_sectors;
518
519 for (disk = 0; disk < zone->nb_dev; disk++) {
520 sector_t dev_start, dev_end;
521 struct md_rdev *rdev;
522 int compare_disk;
523
524 compare_disk = map_disk_shift(disk, zone->nb_dev,
525 zone->disk_shift);
526
527 if (compare_disk < start_disk_index)
528 dev_start = (first_stripe_index + 1) *
529 mddev->chunk_sectors;
530 else if (compare_disk > start_disk_index)
531 dev_start = first_stripe_index * mddev->chunk_sectors;
532 else
533 dev_start = start_disk_offset;
534
535 if (compare_disk < end_disk_index)
536 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
537 else if (compare_disk > end_disk_index)
538 dev_end = last_stripe_index * mddev->chunk_sectors;
539 else
540 dev_end = end_disk_offset;
541
542 if (dev_end <= dev_start)
543 continue;
544
545 rdev = conf->devlist[(zone - conf->strip_zone) *
546 conf->strip_zone[0].nb_dev + disk];
547 md_submit_discard_bio(mddev, rdev, bio,
548 dev_start + zone->dev_start + rdev->data_offset,
549 dev_end - dev_start);
550 }
551 bio_endio(bio);
552 }
553
raid0_map_submit_bio(struct mddev * mddev,struct bio * bio)554 static void raid0_map_submit_bio(struct mddev *mddev, struct bio *bio)
555 {
556 struct r0conf *conf = mddev->private;
557 struct strip_zone *zone;
558 struct md_rdev *tmp_dev;
559 sector_t bio_sector = bio->bi_iter.bi_sector;
560 sector_t sector = bio_sector;
561
562 md_account_bio(mddev, &bio);
563
564 zone = find_zone(mddev->private, §or);
565 switch (conf->layout) {
566 case RAID0_ORIG_LAYOUT:
567 tmp_dev = map_sector(mddev, zone, bio_sector, §or);
568 break;
569 case RAID0_ALT_MULTIZONE_LAYOUT:
570 tmp_dev = map_sector(mddev, zone, sector, §or);
571 break;
572 default:
573 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
574 bio_io_error(bio);
575 return;
576 }
577
578 if (unlikely(is_rdev_broken(tmp_dev))) {
579 bio_io_error(bio);
580 md_error(mddev, tmp_dev);
581 return;
582 }
583
584 bio_set_dev(bio, tmp_dev->bdev);
585 bio->bi_iter.bi_sector = sector + zone->dev_start +
586 tmp_dev->data_offset;
587 mddev_trace_remap(mddev, bio, bio_sector);
588 mddev_check_write_zeroes(mddev, bio);
589 submit_bio_noacct(bio);
590 }
591
raid0_make_request(struct mddev * mddev,struct bio * bio)592 static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
593 {
594 sector_t sector;
595 unsigned chunk_sects;
596 unsigned sectors;
597
598 if (unlikely(bio->bi_opf & REQ_PREFLUSH)
599 && md_flush_request(mddev, bio))
600 return true;
601
602 if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
603 raid0_handle_discard(mddev, bio);
604 return true;
605 }
606
607 sector = bio->bi_iter.bi_sector;
608 chunk_sects = mddev->chunk_sectors;
609
610 sectors = chunk_sects -
611 (likely(is_power_of_2(chunk_sects))
612 ? (sector & (chunk_sects-1))
613 : sector_div(sector, chunk_sects));
614
615 if (sectors < bio_sectors(bio)) {
616 struct bio *split = bio_split(bio, sectors, GFP_NOIO,
617 &mddev->bio_set);
618
619 if (IS_ERR(split)) {
620 bio->bi_status = errno_to_blk_status(PTR_ERR(split));
621 bio_endio(bio);
622 return true;
623 }
624 bio_chain(split, bio);
625 raid0_map_submit_bio(mddev, bio);
626 bio = split;
627 }
628
629 raid0_map_submit_bio(mddev, bio);
630 return true;
631 }
632
raid0_status(struct seq_file * seq,struct mddev * mddev)633 static void raid0_status(struct seq_file *seq, struct mddev *mddev)
634 {
635 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
636 return;
637 }
638
raid0_error(struct mddev * mddev,struct md_rdev * rdev)639 static void raid0_error(struct mddev *mddev, struct md_rdev *rdev)
640 {
641 if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) {
642 char *md_name = mdname(mddev);
643
644 pr_crit("md/raid0%s: Disk failure on %pg detected, failing array.\n",
645 md_name, rdev->bdev);
646 }
647 }
648
raid0_takeover_raid45(struct mddev * mddev)649 static void *raid0_takeover_raid45(struct mddev *mddev)
650 {
651 struct md_rdev *rdev;
652 struct r0conf *priv_conf;
653
654 if (mddev->degraded != 1) {
655 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
656 mdname(mddev),
657 mddev->degraded);
658 return ERR_PTR(-EINVAL);
659 }
660
661 rdev_for_each(rdev, mddev) {
662 /* check slot number for a disk */
663 if (rdev->raid_disk == mddev->raid_disks-1) {
664 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
665 mdname(mddev));
666 return ERR_PTR(-EINVAL);
667 }
668 rdev->sectors = mddev->dev_sectors;
669 }
670
671 /* Set new parameters */
672 mddev->new_level = 0;
673 mddev->new_layout = 0;
674 mddev->new_chunk_sectors = mddev->chunk_sectors;
675 mddev->raid_disks--;
676 mddev->delta_disks = -1;
677 /* make sure it will be not marked as dirty */
678 mddev->recovery_cp = MaxSector;
679 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
680
681 create_strip_zones(mddev, &priv_conf);
682
683 return priv_conf;
684 }
685
raid0_takeover_raid10(struct mddev * mddev)686 static void *raid0_takeover_raid10(struct mddev *mddev)
687 {
688 struct r0conf *priv_conf;
689
690 /* Check layout:
691 * - far_copies must be 1
692 * - near_copies must be 2
693 * - disks number must be even
694 * - all mirrors must be already degraded
695 */
696 if (mddev->layout != ((1 << 8) + 2)) {
697 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
698 mdname(mddev),
699 mddev->layout);
700 return ERR_PTR(-EINVAL);
701 }
702 if (mddev->raid_disks & 1) {
703 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
704 mdname(mddev));
705 return ERR_PTR(-EINVAL);
706 }
707 if (mddev->degraded != (mddev->raid_disks>>1)) {
708 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
709 mdname(mddev));
710 return ERR_PTR(-EINVAL);
711 }
712
713 /* Set new parameters */
714 mddev->new_level = 0;
715 mddev->new_layout = 0;
716 mddev->new_chunk_sectors = mddev->chunk_sectors;
717 mddev->delta_disks = - mddev->raid_disks / 2;
718 mddev->raid_disks += mddev->delta_disks;
719 mddev->degraded = 0;
720 /* make sure it will be not marked as dirty */
721 mddev->recovery_cp = MaxSector;
722 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
723
724 create_strip_zones(mddev, &priv_conf);
725 return priv_conf;
726 }
727
raid0_takeover_raid1(struct mddev * mddev)728 static void *raid0_takeover_raid1(struct mddev *mddev)
729 {
730 struct r0conf *priv_conf;
731 int chunksect;
732
733 /* Check layout:
734 * - (N - 1) mirror drives must be already faulty
735 */
736 if ((mddev->raid_disks - 1) != mddev->degraded) {
737 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
738 mdname(mddev));
739 return ERR_PTR(-EINVAL);
740 }
741
742 /*
743 * a raid1 doesn't have the notion of chunk size, so
744 * figure out the largest suitable size we can use.
745 */
746 chunksect = 64 * 2; /* 64K by default */
747
748 /* The array must be an exact multiple of chunksize */
749 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
750 chunksect >>= 1;
751
752 if ((chunksect << 9) < PAGE_SIZE)
753 /* array size does not allow a suitable chunk size */
754 return ERR_PTR(-EINVAL);
755
756 /* Set new parameters */
757 mddev->new_level = 0;
758 mddev->new_layout = 0;
759 mddev->new_chunk_sectors = chunksect;
760 mddev->chunk_sectors = chunksect;
761 mddev->delta_disks = 1 - mddev->raid_disks;
762 mddev->raid_disks = 1;
763 /* make sure it will be not marked as dirty */
764 mddev->recovery_cp = MaxSector;
765 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
766
767 create_strip_zones(mddev, &priv_conf);
768 return priv_conf;
769 }
770
raid0_takeover(struct mddev * mddev)771 static void *raid0_takeover(struct mddev *mddev)
772 {
773 /* raid0 can take over:
774 * raid4 - if all data disks are active.
775 * raid5 - providing it is Raid4 layout and one disk is faulty
776 * raid10 - assuming we have all necessary active disks
777 * raid1 - with (N -1) mirror drives faulty
778 */
779
780 if (mddev->bitmap) {
781 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
782 mdname(mddev));
783 return ERR_PTR(-EBUSY);
784 }
785 if (mddev->level == 4)
786 return raid0_takeover_raid45(mddev);
787
788 if (mddev->level == 5) {
789 if (mddev->layout == ALGORITHM_PARITY_N)
790 return raid0_takeover_raid45(mddev);
791
792 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
793 mdname(mddev), ALGORITHM_PARITY_N);
794 }
795
796 if (mddev->level == 10)
797 return raid0_takeover_raid10(mddev);
798
799 if (mddev->level == 1)
800 return raid0_takeover_raid1(mddev);
801
802 pr_warn("Takeover from raid%i to raid0 not supported\n",
803 mddev->level);
804
805 return ERR_PTR(-EINVAL);
806 }
807
raid0_quiesce(struct mddev * mddev,int quiesce)808 static void raid0_quiesce(struct mddev *mddev, int quiesce)
809 {
810 }
811
812 static struct md_personality raid0_personality=
813 {
814 .name = "raid0",
815 .level = 0,
816 .owner = THIS_MODULE,
817 .make_request = raid0_make_request,
818 .run = raid0_run,
819 .free = raid0_free,
820 .status = raid0_status,
821 .size = raid0_size,
822 .takeover = raid0_takeover,
823 .quiesce = raid0_quiesce,
824 .error_handler = raid0_error,
825 };
826
raid0_init(void)827 static int __init raid0_init (void)
828 {
829 return register_md_personality (&raid0_personality);
830 }
831
raid0_exit(void)832 static void raid0_exit (void)
833 {
834 unregister_md_personality (&raid0_personality);
835 }
836
837 module_init(raid0_init);
838 module_exit(raid0_exit);
839 MODULE_LICENSE("GPL");
840 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
841 MODULE_ALIAS("md-personality-2"); /* RAID0 */
842 MODULE_ALIAS("md-raid0");
843 MODULE_ALIAS("md-level-0");
844