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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 <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 (1L << MD_HAS_PPL) | \
34 (1L << MD_HAS_MULTIPLE_PPLS))
35
36static int raid0_congested(struct mddev *mddev, int bits)
37{
38 struct r0conf *conf = mddev->private;
39 struct md_rdev **devlist = conf->devlist;
40 int raid_disks = conf->strip_zone[0].nb_dev;
41 int i, ret = 0;
42
43 for (i = 0; i < raid_disks && !ret ; i++) {
44 struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
45
46 ret |= bdi_congested(q->backing_dev_info, bits);
47 }
48 return ret;
49}
50
51/*
52 * inform the user of the raid configuration
53*/
54static void dump_zones(struct mddev *mddev)
55{
56 int j, k;
57 sector_t zone_size = 0;
58 sector_t zone_start = 0;
59 char b[BDEVNAME_SIZE];
60 struct r0conf *conf = mddev->private;
61 int raid_disks = conf->strip_zone[0].nb_dev;
62 pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
63 mdname(mddev),
64 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
65 for (j = 0; j < conf->nr_strip_zones; j++) {
66 char line[200];
67 int len = 0;
68
69 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
70 len += snprintf(line+len, 200-len, "%s%s", k?"/":"",
71 bdevname(conf->devlist[j*raid_disks
72 + k]->bdev, b));
73 pr_debug("md: zone%d=[%s]\n", j, line);
74
75 zone_size = conf->strip_zone[j].zone_end - zone_start;
76 pr_debug(" zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n",
77 (unsigned long long)zone_start>>1,
78 (unsigned long long)conf->strip_zone[j].dev_start>>1,
79 (unsigned long long)zone_size>>1);
80 zone_start = conf->strip_zone[j].zone_end;
81 }
82}
83
84static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
85{
86 int i, c, err;
87 sector_t curr_zone_end, sectors;
88 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
89 struct strip_zone *zone;
90 int cnt;
91 char b[BDEVNAME_SIZE];
92 char b2[BDEVNAME_SIZE];
93 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
94 unsigned short blksize = 512;
95
96 *private_conf = ERR_PTR(-ENOMEM);
97 if (!conf)
98 return -ENOMEM;
99 rdev_for_each(rdev1, mddev) {
100 pr_debug("md/raid0:%s: looking at %s\n",
101 mdname(mddev),
102 bdevname(rdev1->bdev, b));
103 c = 0;
104
105 /* round size to chunk_size */
106 sectors = rdev1->sectors;
107 sector_div(sectors, mddev->chunk_sectors);
108 rdev1->sectors = sectors * mddev->chunk_sectors;
109
110 blksize = max(blksize, queue_logical_block_size(
111 rdev1->bdev->bd_disk->queue));
112
113 rdev_for_each(rdev2, mddev) {
114 pr_debug("md/raid0:%s: comparing %s(%llu)"
115 " with %s(%llu)\n",
116 mdname(mddev),
117 bdevname(rdev1->bdev,b),
118 (unsigned long long)rdev1->sectors,
119 bdevname(rdev2->bdev,b2),
120 (unsigned long long)rdev2->sectors);
121 if (rdev2 == rdev1) {
122 pr_debug("md/raid0:%s: END\n",
123 mdname(mddev));
124 break;
125 }
126 if (rdev2->sectors == rdev1->sectors) {
127 /*
128 * Not unique, don't count it as a new
129 * group
130 */
131 pr_debug("md/raid0:%s: EQUAL\n",
132 mdname(mddev));
133 c = 1;
134 break;
135 }
136 pr_debug("md/raid0:%s: NOT EQUAL\n",
137 mdname(mddev));
138 }
139 if (!c) {
140 pr_debug("md/raid0:%s: ==> UNIQUE\n",
141 mdname(mddev));
142 conf->nr_strip_zones++;
143 pr_debug("md/raid0:%s: %d zones\n",
144 mdname(mddev), conf->nr_strip_zones);
145 }
146 }
147 pr_debug("md/raid0:%s: FINAL %d zones\n",
148 mdname(mddev), conf->nr_strip_zones);
149 /*
150 * now since we have the hard sector sizes, we can make sure
151 * chunk size is a multiple of that sector size
152 */
153 if ((mddev->chunk_sectors << 9) % blksize) {
154 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
155 mdname(mddev),
156 mddev->chunk_sectors << 9, blksize);
157 err = -EINVAL;
158 goto abort;
159 }
160
161 err = -ENOMEM;
162 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
163 conf->nr_strip_zones, GFP_KERNEL);
164 if (!conf->strip_zone)
165 goto abort;
166 conf->devlist = kzalloc(sizeof(struct md_rdev*)*
167 conf->nr_strip_zones*mddev->raid_disks,
168 GFP_KERNEL);
169 if (!conf->devlist)
170 goto abort;
171
172 /* The first zone must contain all devices, so here we check that
173 * there is a proper alignment of slots to devices and find them all
174 */
175 zone = &conf->strip_zone[0];
176 cnt = 0;
177 smallest = NULL;
178 dev = conf->devlist;
179 err = -EINVAL;
180 rdev_for_each(rdev1, mddev) {
181 int j = rdev1->raid_disk;
182
183 if (mddev->level == 10) {
184 /* taking over a raid10-n2 array */
185 j /= 2;
186 rdev1->new_raid_disk = j;
187 }
188
189 if (mddev->level == 1) {
190 /* taiking over a raid1 array-
191 * we have only one active disk
192 */
193 j = 0;
194 rdev1->new_raid_disk = j;
195 }
196
197 if (j < 0) {
198 pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
199 mdname(mddev));
200 goto abort;
201 }
202 if (j >= mddev->raid_disks) {
203 pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
204 mdname(mddev), j);
205 goto abort;
206 }
207 if (dev[j]) {
208 pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
209 mdname(mddev), j);
210 goto abort;
211 }
212 dev[j] = rdev1;
213
214 if (!smallest || (rdev1->sectors < smallest->sectors))
215 smallest = rdev1;
216 cnt++;
217 }
218 if (cnt != mddev->raid_disks) {
219 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
220 mdname(mddev), cnt, mddev->raid_disks);
221 goto abort;
222 }
223 zone->nb_dev = cnt;
224 zone->zone_end = smallest->sectors * cnt;
225
226 curr_zone_end = zone->zone_end;
227
228 /* now do the other zones */
229 for (i = 1; i < conf->nr_strip_zones; i++)
230 {
231 int j;
232
233 zone = conf->strip_zone + i;
234 dev = conf->devlist + i * mddev->raid_disks;
235
236 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
237 zone->dev_start = smallest->sectors;
238 smallest = NULL;
239 c = 0;
240
241 for (j=0; j<cnt; j++) {
242 rdev = conf->devlist[j];
243 if (rdev->sectors <= zone->dev_start) {
244 pr_debug("md/raid0:%s: checking %s ... nope\n",
245 mdname(mddev),
246 bdevname(rdev->bdev, b));
247 continue;
248 }
249 pr_debug("md/raid0:%s: checking %s ..."
250 " contained as device %d\n",
251 mdname(mddev),
252 bdevname(rdev->bdev, b), c);
253 dev[c] = rdev;
254 c++;
255 if (!smallest || rdev->sectors < smallest->sectors) {
256 smallest = rdev;
257 pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
258 mdname(mddev),
259 (unsigned long long)rdev->sectors);
260 }
261 }
262
263 zone->nb_dev = c;
264 sectors = (smallest->sectors - zone->dev_start) * c;
265 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
266 mdname(mddev),
267 zone->nb_dev, (unsigned long long)sectors);
268
269 curr_zone_end += sectors;
270 zone->zone_end = curr_zone_end;
271
272 pr_debug("md/raid0:%s: current zone start: %llu\n",
273 mdname(mddev),
274 (unsigned long long)smallest->sectors);
275 }
276
277 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
278 *private_conf = conf;
279
280 return 0;
281abort:
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 */
292static 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*/
312static 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
345static 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
360static void raid0_free(struct mddev *mddev, void *priv);
361
362static 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 if (mddev->queue) {
415 /* calculate the max read-ahead size.
416 * For read-ahead of large files to be effective, we need to
417 * readahead at least twice a whole stripe. i.e. number of devices
418 * multiplied by chunk size times 2.
419 * If an individual device has an ra_pages greater than the
420 * chunk size, then we will not drive that device as hard as it
421 * wants. We consider this a configuration error: a larger
422 * chunksize should be used in that case.
423 */
424 int stripe = mddev->raid_disks *
425 (mddev->chunk_sectors << 9) / PAGE_SIZE;
426 if (mddev->queue->backing_dev_info->ra_pages < 2* stripe)
427 mddev->queue->backing_dev_info->ra_pages = 2* stripe;
428 }
429
430 dump_zones(mddev);
431
432 ret = md_integrity_register(mddev);
433
434 return ret;
435}
436
437static void raid0_free(struct mddev *mddev, void *priv)
438{
439 struct r0conf *conf = priv;
440
441 kfree(conf->strip_zone);
442 kfree(conf->devlist);
443 kfree(conf);
444}
445
446/*
447 * Is io distribute over 1 or more chunks ?
448*/
449static inline int is_io_in_chunk_boundary(struct mddev *mddev,
450 unsigned int chunk_sects, struct bio *bio)
451{
452 if (likely(is_power_of_2(chunk_sects))) {
453 return chunk_sects >=
454 ((bio->bi_iter.bi_sector & (chunk_sects-1))
455 + bio_sectors(bio));
456 } else{
457 sector_t sector = bio->bi_iter.bi_sector;
458 return chunk_sects >= (sector_div(sector, chunk_sects)
459 + bio_sectors(bio));
460 }
461}
462
463static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
464{
465 struct r0conf *conf = mddev->private;
466 struct strip_zone *zone;
467 sector_t start = bio->bi_iter.bi_sector;
468 sector_t end;
469 unsigned int stripe_size;
470 sector_t first_stripe_index, last_stripe_index;
471 sector_t start_disk_offset;
472 unsigned int start_disk_index;
473 sector_t end_disk_offset;
474 unsigned int end_disk_index;
475 unsigned int disk;
476
477 zone = find_zone(conf, &start);
478
479 if (bio_end_sector(bio) > zone->zone_end) {
480 struct bio *split = bio_split(bio,
481 zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO,
482 mddev->bio_set);
483 bio_chain(split, bio);
484 generic_make_request(bio);
485 bio = split;
486 end = zone->zone_end;
487 } else
488 end = bio_end_sector(bio);
489
490 if (zone != conf->strip_zone)
491 end = end - zone[-1].zone_end;
492
493 /* Now start and end is the offset in zone */
494 stripe_size = zone->nb_dev * mddev->chunk_sectors;
495
496 first_stripe_index = start;
497 sector_div(first_stripe_index, stripe_size);
498 last_stripe_index = end;
499 sector_div(last_stripe_index, stripe_size);
500
501 start_disk_index = (int)(start - first_stripe_index * stripe_size) /
502 mddev->chunk_sectors;
503 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
504 mddev->chunk_sectors) +
505 first_stripe_index * mddev->chunk_sectors;
506 end_disk_index = (int)(end - last_stripe_index * stripe_size) /
507 mddev->chunk_sectors;
508 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
509 mddev->chunk_sectors) +
510 last_stripe_index * mddev->chunk_sectors;
511
512 for (disk = 0; disk < zone->nb_dev; disk++) {
513 sector_t dev_start, dev_end;
514 struct bio *discard_bio = NULL;
515 struct md_rdev *rdev;
516
517 if (disk < start_disk_index)
518 dev_start = (first_stripe_index + 1) *
519 mddev->chunk_sectors;
520 else if (disk > start_disk_index)
521 dev_start = first_stripe_index * mddev->chunk_sectors;
522 else
523 dev_start = start_disk_offset;
524
525 if (disk < end_disk_index)
526 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
527 else if (disk > end_disk_index)
528 dev_end = last_stripe_index * mddev->chunk_sectors;
529 else
530 dev_end = end_disk_offset;
531
532 if (dev_end <= dev_start)
533 continue;
534
535 rdev = conf->devlist[(zone - conf->strip_zone) *
536 conf->strip_zone[0].nb_dev + disk];
537 if (__blkdev_issue_discard(rdev->bdev,
538 dev_start + zone->dev_start + rdev->data_offset,
539 dev_end - dev_start, GFP_NOIO, 0, &discard_bio) ||
540 !discard_bio)
541 continue;
542 bio_chain(discard_bio, bio);
543 bio_clone_blkcg_association(discard_bio, bio);
544 if (mddev->gendisk)
545 trace_block_bio_remap(bdev_get_queue(rdev->bdev),
546 discard_bio, disk_devt(mddev->gendisk),
547 bio->bi_iter.bi_sector);
548 generic_make_request(discard_bio);
549 }
550 bio_endio(bio);
551}
552
553static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
554{
555 struct strip_zone *zone;
556 struct md_rdev *tmp_dev;
557 sector_t bio_sector;
558 sector_t sector;
559 unsigned chunk_sects;
560 unsigned sectors;
561
562 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
563 md_flush_request(mddev, bio);
564 return true;
565 }
566
567 if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
568 raid0_handle_discard(mddev, bio);
569 return true;
570 }
571
572 bio_sector = bio->bi_iter.bi_sector;
573 sector = bio_sector;
574 chunk_sects = mddev->chunk_sectors;
575
576 sectors = chunk_sects -
577 (likely(is_power_of_2(chunk_sects))
578 ? (sector & (chunk_sects-1))
579 : sector_div(sector, chunk_sects));
580
581 /* Restore due to sector_div */
582 sector = bio_sector;
583
584 if (sectors < bio_sectors(bio)) {
585 struct bio *split = bio_split(bio, sectors, GFP_NOIO, mddev->bio_set);
586 bio_chain(split, bio);
587 generic_make_request(bio);
588 bio = split;
589 }
590
591 zone = find_zone(mddev->private, §or);
592 tmp_dev = map_sector(mddev, zone, sector, §or);
593 bio_set_dev(bio, tmp_dev->bdev);
594 bio->bi_iter.bi_sector = sector + zone->dev_start +
595 tmp_dev->data_offset;
596
597 if (mddev->gendisk)
598 trace_block_bio_remap(bio->bi_disk->queue, bio,
599 disk_devt(mddev->gendisk), bio_sector);
600 mddev_check_writesame(mddev, bio);
601 mddev_check_write_zeroes(mddev, bio);
602 generic_make_request(bio);
603 return true;
604}
605
606static void raid0_status(struct seq_file *seq, struct mddev *mddev)
607{
608 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
609 return;
610}
611
612static void *raid0_takeover_raid45(struct mddev *mddev)
613{
614 struct md_rdev *rdev;
615 struct r0conf *priv_conf;
616
617 if (mddev->degraded != 1) {
618 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
619 mdname(mddev),
620 mddev->degraded);
621 return ERR_PTR(-EINVAL);
622 }
623
624 rdev_for_each(rdev, mddev) {
625 /* check slot number for a disk */
626 if (rdev->raid_disk == mddev->raid_disks-1) {
627 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
628 mdname(mddev));
629 return ERR_PTR(-EINVAL);
630 }
631 rdev->sectors = mddev->dev_sectors;
632 }
633
634 /* Set new parameters */
635 mddev->new_level = 0;
636 mddev->new_layout = 0;
637 mddev->new_chunk_sectors = mddev->chunk_sectors;
638 mddev->raid_disks--;
639 mddev->delta_disks = -1;
640 /* make sure it will be not marked as dirty */
641 mddev->recovery_cp = MaxSector;
642 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
643
644 create_strip_zones(mddev, &priv_conf);
645
646 return priv_conf;
647}
648
649static void *raid0_takeover_raid10(struct mddev *mddev)
650{
651 struct r0conf *priv_conf;
652
653 /* Check layout:
654 * - far_copies must be 1
655 * - near_copies must be 2
656 * - disks number must be even
657 * - all mirrors must be already degraded
658 */
659 if (mddev->layout != ((1 << 8) + 2)) {
660 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
661 mdname(mddev),
662 mddev->layout);
663 return ERR_PTR(-EINVAL);
664 }
665 if (mddev->raid_disks & 1) {
666 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
667 mdname(mddev));
668 return ERR_PTR(-EINVAL);
669 }
670 if (mddev->degraded != (mddev->raid_disks>>1)) {
671 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
672 mdname(mddev));
673 return ERR_PTR(-EINVAL);
674 }
675
676 /* Set new parameters */
677 mddev->new_level = 0;
678 mddev->new_layout = 0;
679 mddev->new_chunk_sectors = mddev->chunk_sectors;
680 mddev->delta_disks = - mddev->raid_disks / 2;
681 mddev->raid_disks += mddev->delta_disks;
682 mddev->degraded = 0;
683 /* make sure it will be not marked as dirty */
684 mddev->recovery_cp = MaxSector;
685 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
686
687 create_strip_zones(mddev, &priv_conf);
688 return priv_conf;
689}
690
691static void *raid0_takeover_raid1(struct mddev *mddev)
692{
693 struct r0conf *priv_conf;
694 int chunksect;
695
696 /* Check layout:
697 * - (N - 1) mirror drives must be already faulty
698 */
699 if ((mddev->raid_disks - 1) != mddev->degraded) {
700 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
701 mdname(mddev));
702 return ERR_PTR(-EINVAL);
703 }
704
705 /*
706 * a raid1 doesn't have the notion of chunk size, so
707 * figure out the largest suitable size we can use.
708 */
709 chunksect = 64 * 2; /* 64K by default */
710
711 /* The array must be an exact multiple of chunksize */
712 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
713 chunksect >>= 1;
714
715 if ((chunksect << 9) < PAGE_SIZE)
716 /* array size does not allow a suitable chunk size */
717 return ERR_PTR(-EINVAL);
718
719 /* Set new parameters */
720 mddev->new_level = 0;
721 mddev->new_layout = 0;
722 mddev->new_chunk_sectors = chunksect;
723 mddev->chunk_sectors = chunksect;
724 mddev->delta_disks = 1 - mddev->raid_disks;
725 mddev->raid_disks = 1;
726 /* make sure it will be not marked as dirty */
727 mddev->recovery_cp = MaxSector;
728 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
729
730 create_strip_zones(mddev, &priv_conf);
731 return priv_conf;
732}
733
734static void *raid0_takeover(struct mddev *mddev)
735{
736 /* raid0 can take over:
737 * raid4 - if all data disks are active.
738 * raid5 - providing it is Raid4 layout and one disk is faulty
739 * raid10 - assuming we have all necessary active disks
740 * raid1 - with (N -1) mirror drives faulty
741 */
742
743 if (mddev->bitmap) {
744 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
745 mdname(mddev));
746 return ERR_PTR(-EBUSY);
747 }
748 if (mddev->level == 4)
749 return raid0_takeover_raid45(mddev);
750
751 if (mddev->level == 5) {
752 if (mddev->layout == ALGORITHM_PARITY_N)
753 return raid0_takeover_raid45(mddev);
754
755 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
756 mdname(mddev), ALGORITHM_PARITY_N);
757 }
758
759 if (mddev->level == 10)
760 return raid0_takeover_raid10(mddev);
761
762 if (mddev->level == 1)
763 return raid0_takeover_raid1(mddev);
764
765 pr_warn("Takeover from raid%i to raid0 not supported\n",
766 mddev->level);
767
768 return ERR_PTR(-EINVAL);
769}
770
771static void raid0_quiesce(struct mddev *mddev, int quiesce)
772{
773}
774
775static struct md_personality raid0_personality=
776{
777 .name = "raid0",
778 .level = 0,
779 .owner = THIS_MODULE,
780 .make_request = raid0_make_request,
781 .run = raid0_run,
782 .free = raid0_free,
783 .status = raid0_status,
784 .size = raid0_size,
785 .takeover = raid0_takeover,
786 .quiesce = raid0_quiesce,
787 .congested = raid0_congested,
788};
789
790static int __init raid0_init (void)
791{
792 return register_md_personality (&raid0_personality);
793}
794
795static void raid0_exit (void)
796{
797 unregister_md_personality (&raid0_personality);
798}
799
800module_init(raid0_init);
801module_exit(raid0_exit);
802MODULE_LICENSE("GPL");
803MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
804MODULE_ALIAS("md-personality-2"); /* RAID0 */
805MODULE_ALIAS("md-raid0");
806MODULE_ALIAS("md-level-0");