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 (1L << MD_FAILLAST_DEV) | \
32 (1L << MD_SERIALIZE_POLICY))
33
34 /*
35 * inform the user of the raid configuration
36 */
dump_zones(struct mddev * mddev)37 static void dump_zones(struct mddev *mddev)
38 {
39 int j, k;
40 sector_t zone_size = 0;
41 sector_t zone_start = 0;
42 struct r0conf *conf = mddev->private;
43 int raid_disks = conf->strip_zone[0].nb_dev;
44 pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
45 mdname(mddev),
46 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
47 for (j = 0; j < conf->nr_strip_zones; j++) {
48 char line[200];
49 int len = 0;
50
51 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
52 len += scnprintf(line+len, 200-len, "%s%pg", k?"/":"",
53 conf->devlist[j * raid_disks + k]->bdev);
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 struct r0conf *conf = kzalloc_obj(*conf);
73 unsigned int blksize = 512;
74
75 if (!mddev_is_dm(mddev))
76 blksize = queue_logical_block_size(mddev->gendisk->queue);
77
78 *private_conf = ERR_PTR(-ENOMEM);
79 if (!conf)
80 return -ENOMEM;
81 rdev_for_each(rdev1, mddev) {
82 pr_debug("md/raid0:%s: looking at %pg\n",
83 mdname(mddev),
84 rdev1->bdev);
85 c = 0;
86
87 /* round size to chunk_size */
88 sectors = rdev1->sectors;
89 sector_div(sectors, mddev->chunk_sectors);
90 rdev1->sectors = sectors * mddev->chunk_sectors;
91
92 if (mddev_is_dm(mddev))
93 blksize = max(blksize, queue_logical_block_size(
94 rdev1->bdev->bd_disk->queue));
95
96 rdev_for_each(rdev2, mddev) {
97 pr_debug("md/raid0:%s: comparing %pg(%llu)"
98 " with %pg(%llu)\n",
99 mdname(mddev),
100 rdev1->bdev,
101 (unsigned long long)rdev1->sectors,
102 rdev2->bdev,
103 (unsigned long long)rdev2->sectors);
104 if (rdev2 == rdev1) {
105 pr_debug("md/raid0:%s: END\n",
106 mdname(mddev));
107 break;
108 }
109 if (rdev2->sectors == rdev1->sectors) {
110 /*
111 * Not unique, don't count it as a new
112 * group
113 */
114 pr_debug("md/raid0:%s: EQUAL\n",
115 mdname(mddev));
116 c = 1;
117 break;
118 }
119 pr_debug("md/raid0:%s: NOT EQUAL\n",
120 mdname(mddev));
121 }
122 if (!c) {
123 pr_debug("md/raid0:%s: ==> UNIQUE\n",
124 mdname(mddev));
125 conf->nr_strip_zones++;
126 pr_debug("md/raid0:%s: %d zones\n",
127 mdname(mddev), conf->nr_strip_zones);
128 }
129 }
130 pr_debug("md/raid0:%s: FINAL %d zones\n",
131 mdname(mddev), conf->nr_strip_zones);
132
133 /*
134 * now since we have the hard sector sizes, we can make sure
135 * chunk size is a multiple of that sector size
136 */
137 if ((mddev->chunk_sectors << 9) % blksize) {
138 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
139 mdname(mddev),
140 mddev->chunk_sectors << 9, blksize);
141 err = -EINVAL;
142 goto abort;
143 }
144
145 err = -ENOMEM;
146 conf->strip_zone = kzalloc_objs(struct strip_zone, conf->nr_strip_zones);
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 %pg ... nope\n",
229 mdname(mddev),
230 rdev->bdev);
231 continue;
232 }
233 pr_debug("md/raid0:%s: checking %pg ..."
234 " contained as device %d\n",
235 mdname(mddev),
236 rdev->bdev, 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 if (conf->layout == RAID0_ORIG_LAYOUT) {
278 for (i = 1; i < conf->nr_strip_zones; i++) {
279 sector_t first_sector = conf->strip_zone[i-1].zone_end;
280
281 sector_div(first_sector, mddev->chunk_sectors);
282 zone = conf->strip_zone + i;
283 /* disk_shift is first disk index used in the zone */
284 zone->disk_shift = sector_div(first_sector,
285 zone->nb_dev);
286 }
287 }
288
289 pr_debug("md/raid0:%s: done.\n", mdname(mddev));
290 *private_conf = conf;
291
292 return 0;
293 abort:
294 kfree(conf->strip_zone);
295 kfree(conf->devlist);
296 kfree(conf);
297 *private_conf = ERR_PTR(err);
298 return err;
299 }
300
301 /* Find the zone which holds a particular offset
302 * Update *sectorp to be an offset in that zone
303 */
find_zone(struct r0conf * conf,sector_t * sectorp)304 static struct strip_zone *find_zone(struct r0conf *conf,
305 sector_t *sectorp)
306 {
307 int i;
308 struct strip_zone *z = conf->strip_zone;
309 sector_t sector = *sectorp;
310
311 for (i = 0; i < conf->nr_strip_zones; i++)
312 if (sector < z[i].zone_end) {
313 if (i)
314 *sectorp = sector - z[i-1].zone_end;
315 return z + i;
316 }
317 BUG();
318 }
319
320 /*
321 * remaps the bio to the target device. we separate two flows.
322 * power 2 flow and a general flow for the sake of performance
323 */
map_sector(struct mddev * mddev,struct strip_zone * zone,sector_t sector,sector_t * sector_offset)324 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
325 sector_t sector, sector_t *sector_offset)
326 {
327 unsigned int sect_in_chunk;
328 sector_t chunk;
329 struct r0conf *conf = mddev->private;
330 int raid_disks = conf->strip_zone[0].nb_dev;
331 unsigned int chunk_sects = mddev->chunk_sectors;
332
333 if (is_power_of_2(chunk_sects)) {
334 int chunksect_bits = ffz(~chunk_sects);
335 /* find the sector offset inside the chunk */
336 sect_in_chunk = sector & (chunk_sects - 1);
337 sector >>= chunksect_bits;
338 /* chunk in zone */
339 chunk = *sector_offset;
340 /* quotient is the chunk in real device*/
341 sector_div(chunk, zone->nb_dev << chunksect_bits);
342 } else{
343 sect_in_chunk = sector_div(sector, chunk_sects);
344 chunk = *sector_offset;
345 sector_div(chunk, chunk_sects * zone->nb_dev);
346 }
347 /*
348 * position the bio over the real device
349 * real sector = chunk in device + starting of zone
350 * + the position in the chunk
351 */
352 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
353 return conf->devlist[(zone - conf->strip_zone)*raid_disks
354 + sector_div(sector, zone->nb_dev)];
355 }
356
raid0_size(struct mddev * mddev,sector_t sectors,int raid_disks)357 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
358 {
359 sector_t array_sectors = 0;
360 struct md_rdev *rdev;
361
362 WARN_ONCE(sectors || raid_disks,
363 "%s does not support generic reshape\n", __func__);
364
365 rdev_for_each(rdev, mddev)
366 array_sectors += (rdev->sectors &
367 ~(sector_t)(mddev->chunk_sectors-1));
368
369 return array_sectors;
370 }
371
raid0_free(struct mddev * mddev,void * priv)372 static void raid0_free(struct mddev *mddev, void *priv)
373 {
374 struct r0conf *conf = priv;
375
376 kfree(conf->strip_zone);
377 kfree(conf->devlist);
378 kfree(conf);
379 }
380
raid0_set_limits(struct mddev * mddev)381 static int raid0_set_limits(struct mddev *mddev)
382 {
383 struct queue_limits lim;
384 int err;
385
386 md_init_stacking_limits(&lim);
387 lim.max_hw_sectors = mddev->chunk_sectors;
388 lim.max_write_zeroes_sectors = mddev->chunk_sectors;
389 lim.max_hw_wzeroes_unmap_sectors = mddev->chunk_sectors;
390 lim.logical_block_size = mddev->logical_block_size;
391 lim.io_min = mddev->chunk_sectors << 9;
392 lim.io_opt = lim.io_min * mddev->raid_disks;
393 lim.chunk_sectors = mddev->chunk_sectors;
394 lim.features |= BLK_FEAT_ATOMIC_WRITES;
395 err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
396 if (err)
397 return err;
398 return queue_limits_set(mddev->gendisk->queue, &lim);
399 }
400
raid0_run(struct mddev * mddev)401 static int raid0_run(struct mddev *mddev)
402 {
403 struct r0conf *conf;
404 int ret;
405
406 if (mddev->chunk_sectors == 0) {
407 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
408 return -EINVAL;
409 }
410 if (md_check_no_bitmap(mddev))
411 return -EINVAL;
412
413 if (!mddev_is_dm(mddev)) {
414 ret = raid0_set_limits(mddev);
415 if (ret)
416 return ret;
417 }
418
419 /* if private is not null, we are here after takeover */
420 if (mddev->private == NULL) {
421 ret = create_strip_zones(mddev, &conf);
422 if (ret < 0)
423 return ret;
424 mddev->private = conf;
425 }
426 conf = mddev->private;
427
428 /* calculate array device size */
429 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
430
431 pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
432 mdname(mddev),
433 (unsigned long long)mddev->array_sectors);
434
435 dump_zones(mddev);
436
437 return md_integrity_register(mddev);
438 }
439
440 /*
441 * Convert disk_index to the disk order in which it is read/written.
442 * For example, if we have 4 disks, they are numbered 0,1,2,3. If we
443 * write the disks starting at disk 3, then the read/write order would
444 * be disk 3, then 0, then 1, and then disk 2 and we want map_disk_shift()
445 * to map the disks as follows 0,1,2,3 => 1,2,3,0. So disk 0 would map
446 * to 1, 1 to 2, 2 to 3, and 3 to 0. That way we can compare disks in
447 * that 'output' space to understand the read/write disk ordering.
448 */
map_disk_shift(int disk_index,int num_disks,int disk_shift)449 static int map_disk_shift(int disk_index, int num_disks, int disk_shift)
450 {
451 return ((disk_index + num_disks - disk_shift) % num_disks);
452 }
453
raid0_handle_discard(struct mddev * mddev,struct bio * bio)454 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
455 {
456 struct r0conf *conf = mddev->private;
457 struct strip_zone *zone;
458 sector_t start = bio->bi_iter.bi_sector;
459 sector_t end;
460 unsigned int stripe_size;
461 sector_t first_stripe_index, last_stripe_index;
462 sector_t start_disk_offset;
463 unsigned int start_disk_index;
464 sector_t end_disk_offset;
465 unsigned int end_disk_index;
466 unsigned int disk;
467 sector_t orig_start, orig_end;
468
469 orig_start = start;
470 zone = find_zone(conf, &start);
471
472 if (bio_end_sector(bio) > zone->zone_end) {
473 bio = bio_submit_split_bioset(bio,
474 zone->zone_end - bio->bi_iter.bi_sector,
475 &mddev->bio_set);
476 if (!bio)
477 return;
478
479 end = zone->zone_end;
480 } else {
481 end = bio_end_sector(bio);
482 }
483
484 orig_end = end;
485 if (zone != conf->strip_zone)
486 end = end - zone[-1].zone_end;
487
488 /* Now start and end is the offset in zone */
489 stripe_size = zone->nb_dev * mddev->chunk_sectors;
490
491 first_stripe_index = start;
492 sector_div(first_stripe_index, stripe_size);
493 last_stripe_index = end;
494 sector_div(last_stripe_index, stripe_size);
495
496 /* In the first zone the original and alternate layouts are the same */
497 if ((conf->layout == RAID0_ORIG_LAYOUT) && (zone != conf->strip_zone)) {
498 sector_div(orig_start, mddev->chunk_sectors);
499 start_disk_index = sector_div(orig_start, zone->nb_dev);
500 start_disk_index = map_disk_shift(start_disk_index,
501 zone->nb_dev,
502 zone->disk_shift);
503 sector_div(orig_end, mddev->chunk_sectors);
504 end_disk_index = sector_div(orig_end, zone->nb_dev);
505 end_disk_index = map_disk_shift(end_disk_index,
506 zone->nb_dev, zone->disk_shift);
507 } else {
508 start_disk_index = (int)(start - first_stripe_index * stripe_size) /
509 mddev->chunk_sectors;
510 end_disk_index = (int)(end - last_stripe_index * stripe_size) /
511 mddev->chunk_sectors;
512 }
513 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
514 mddev->chunk_sectors) +
515 first_stripe_index * mddev->chunk_sectors;
516 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
517 mddev->chunk_sectors) +
518 last_stripe_index * mddev->chunk_sectors;
519
520 for (disk = 0; disk < zone->nb_dev; disk++) {
521 sector_t dev_start, dev_end;
522 struct md_rdev *rdev;
523 int compare_disk;
524
525 compare_disk = map_disk_shift(disk, zone->nb_dev,
526 zone->disk_shift);
527
528 if (compare_disk < start_disk_index)
529 dev_start = (first_stripe_index + 1) *
530 mddev->chunk_sectors;
531 else if (compare_disk > start_disk_index)
532 dev_start = first_stripe_index * mddev->chunk_sectors;
533 else
534 dev_start = start_disk_offset;
535
536 if (compare_disk < end_disk_index)
537 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
538 else if (compare_disk > end_disk_index)
539 dev_end = last_stripe_index * mddev->chunk_sectors;
540 else
541 dev_end = end_disk_offset;
542
543 if (dev_end <= dev_start)
544 continue;
545
546 rdev = conf->devlist[(zone - conf->strip_zone) *
547 conf->strip_zone[0].nb_dev + disk];
548 md_submit_discard_bio(mddev, rdev, bio,
549 dev_start + zone->dev_start + rdev->data_offset,
550 dev_end - dev_start);
551 }
552 bio_endio(bio);
553 }
554
raid0_map_submit_bio(struct mddev * mddev,struct bio * bio)555 static void raid0_map_submit_bio(struct mddev *mddev, struct bio *bio)
556 {
557 struct r0conf *conf = mddev->private;
558 struct strip_zone *zone;
559 struct md_rdev *tmp_dev;
560 sector_t bio_sector = bio->bi_iter.bi_sector;
561 sector_t sector = bio_sector;
562
563 md_account_bio(mddev, &bio);
564
565 zone = find_zone(mddev->private, §or);
566 switch (conf->layout) {
567 case RAID0_ORIG_LAYOUT:
568 tmp_dev = map_sector(mddev, zone, bio_sector, §or);
569 break;
570 case RAID0_ALT_MULTIZONE_LAYOUT:
571 tmp_dev = map_sector(mddev, zone, sector, §or);
572 break;
573 default:
574 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
575 bio_io_error(bio);
576 return;
577 }
578
579 if (unlikely(is_rdev_broken(tmp_dev))) {
580 bio_io_error(bio);
581 md_error(mddev, tmp_dev);
582 return;
583 }
584
585 bio_set_dev(bio, tmp_dev->bdev);
586 bio->bi_iter.bi_sector = sector + zone->dev_start +
587 tmp_dev->data_offset;
588 mddev_trace_remap(mddev, bio, bio_sector);
589 mddev_check_write_zeroes(mddev, bio);
590 submit_bio_noacct(bio);
591 }
592
raid0_make_request(struct mddev * mddev,struct bio * bio)593 static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
594 {
595 sector_t sector;
596 unsigned chunk_sects;
597 unsigned sectors;
598
599 if (unlikely(bio->bi_opf & REQ_PREFLUSH)
600 && md_flush_request(mddev, bio))
601 return true;
602
603 if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
604 raid0_handle_discard(mddev, bio);
605 return true;
606 }
607
608 sector = bio->bi_iter.bi_sector;
609 chunk_sects = mddev->chunk_sectors;
610
611 sectors = chunk_sects -
612 (likely(is_power_of_2(chunk_sects))
613 ? (sector & (chunk_sects-1))
614 : sector_div(sector, chunk_sects));
615
616 if (sectors < bio_sectors(bio)) {
617 bio = bio_submit_split_bioset(bio, sectors,
618 &mddev->bio_set);
619 if (!bio)
620 return true;
621 }
622
623 raid0_map_submit_bio(mddev, bio);
624 return true;
625 }
626
raid0_status(struct seq_file * seq,struct mddev * mddev)627 static void raid0_status(struct seq_file *seq, struct mddev *mddev)
628 {
629 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
630 return;
631 }
632
raid0_error(struct mddev * mddev,struct md_rdev * rdev)633 static void raid0_error(struct mddev *mddev, struct md_rdev *rdev)
634 {
635 if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) {
636 char *md_name = mdname(mddev);
637
638 pr_crit("md/raid0%s: Disk failure on %pg detected, failing array.\n",
639 md_name, rdev->bdev);
640 }
641 }
642
raid0_takeover_raid45(struct mddev * mddev)643 static void *raid0_takeover_raid45(struct mddev *mddev)
644 {
645 struct md_rdev *rdev;
646 struct r0conf *priv_conf;
647
648 if (mddev->degraded != 1) {
649 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
650 mdname(mddev),
651 mddev->degraded);
652 return ERR_PTR(-EINVAL);
653 }
654
655 rdev_for_each(rdev, mddev) {
656 /* check slot number for a disk */
657 if (rdev->raid_disk == mddev->raid_disks-1) {
658 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
659 mdname(mddev));
660 return ERR_PTR(-EINVAL);
661 }
662 rdev->sectors = mddev->dev_sectors;
663 }
664
665 /* Set new parameters */
666 mddev->new_level = 0;
667 mddev->new_layout = 0;
668 mddev->new_chunk_sectors = mddev->chunk_sectors;
669 mddev->raid_disks--;
670 mddev->delta_disks = -1;
671 /* make sure it will be not marked as dirty */
672 mddev->resync_offset = MaxSector;
673 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
674
675 create_strip_zones(mddev, &priv_conf);
676
677 return priv_conf;
678 }
679
raid0_takeover_raid10(struct mddev * mddev)680 static void *raid0_takeover_raid10(struct mddev *mddev)
681 {
682 struct r0conf *priv_conf;
683
684 /* Check layout:
685 * - far_copies must be 1
686 * - near_copies must be 2
687 * - disks number must be even
688 * - all mirrors must be already degraded
689 */
690 if (mddev->layout != ((1 << 8) + 2)) {
691 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
692 mdname(mddev),
693 mddev->layout);
694 return ERR_PTR(-EINVAL);
695 }
696 if (mddev->raid_disks & 1) {
697 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
698 mdname(mddev));
699 return ERR_PTR(-EINVAL);
700 }
701 if (mddev->degraded != (mddev->raid_disks>>1)) {
702 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
703 mdname(mddev));
704 return ERR_PTR(-EINVAL);
705 }
706
707 /* Set new parameters */
708 mddev->new_level = 0;
709 mddev->new_layout = 0;
710 mddev->new_chunk_sectors = mddev->chunk_sectors;
711 mddev->delta_disks = - mddev->raid_disks / 2;
712 mddev->raid_disks += mddev->delta_disks;
713 mddev->degraded = 0;
714 /* make sure it will be not marked as dirty */
715 mddev->resync_offset = MaxSector;
716 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
717
718 create_strip_zones(mddev, &priv_conf);
719 return priv_conf;
720 }
721
raid0_takeover_raid1(struct mddev * mddev)722 static void *raid0_takeover_raid1(struct mddev *mddev)
723 {
724 struct r0conf *priv_conf;
725 int chunksect;
726
727 /* Check layout:
728 * - (N - 1) mirror drives must be already faulty
729 */
730 if ((mddev->raid_disks - 1) != mddev->degraded) {
731 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
732 mdname(mddev));
733 return ERR_PTR(-EINVAL);
734 }
735
736 /*
737 * a raid1 doesn't have the notion of chunk size, so
738 * figure out the largest suitable size we can use.
739 */
740 chunksect = 64 * 2; /* 64K by default */
741
742 /* The array must be an exact multiple of chunksize */
743 while (chunksect && (mddev->array_sectors & (chunksect - 1)))
744 chunksect >>= 1;
745
746 if ((chunksect << 9) < PAGE_SIZE)
747 /* array size does not allow a suitable chunk size */
748 return ERR_PTR(-EINVAL);
749
750 /* Set new parameters */
751 mddev->new_level = 0;
752 mddev->new_layout = 0;
753 mddev->new_chunk_sectors = chunksect;
754 mddev->chunk_sectors = chunksect;
755 mddev->delta_disks = 1 - mddev->raid_disks;
756 mddev->raid_disks = 1;
757 /* make sure it will be not marked as dirty */
758 mddev->resync_offset = MaxSector;
759 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
760
761 create_strip_zones(mddev, &priv_conf);
762 return priv_conf;
763 }
764
raid0_takeover(struct mddev * mddev)765 static void *raid0_takeover(struct mddev *mddev)
766 {
767 /* raid0 can take over:
768 * raid4 - if all data disks are active.
769 * raid5 - providing it is Raid4 layout and one disk is faulty
770 * raid10 - assuming we have all necessary active disks
771 * raid1 - with (N -1) mirror drives faulty
772 */
773
774 if (mddev->bitmap) {
775 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
776 mdname(mddev));
777 return ERR_PTR(-EBUSY);
778 }
779 if (mddev->level == 4)
780 return raid0_takeover_raid45(mddev);
781
782 if (mddev->level == 5) {
783 if (mddev->layout == ALGORITHM_PARITY_N)
784 return raid0_takeover_raid45(mddev);
785
786 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
787 mdname(mddev), ALGORITHM_PARITY_N);
788 }
789
790 if (mddev->level == 10)
791 return raid0_takeover_raid10(mddev);
792
793 if (mddev->level == 1)
794 return raid0_takeover_raid1(mddev);
795
796 pr_warn("Takeover from raid%i to raid0 not supported\n",
797 mddev->level);
798
799 return ERR_PTR(-EINVAL);
800 }
801
raid0_quiesce(struct mddev * mddev,int quiesce)802 static void raid0_quiesce(struct mddev *mddev, int quiesce)
803 {
804 }
805
806 static struct md_personality raid0_personality=
807 {
808 .head = {
809 .type = MD_PERSONALITY,
810 .id = ID_RAID0,
811 .name = "raid0",
812 .owner = THIS_MODULE,
813 },
814
815 .make_request = raid0_make_request,
816 .run = raid0_run,
817 .free = raid0_free,
818 .status = raid0_status,
819 .size = raid0_size,
820 .takeover = raid0_takeover,
821 .quiesce = raid0_quiesce,
822 .error_handler = raid0_error,
823 };
824
raid0_init(void)825 static int __init raid0_init(void)
826 {
827 return register_md_submodule(&raid0_personality.head);
828 }
829
raid0_exit(void)830 static void __exit raid0_exit(void)
831 {
832 unregister_md_submodule(&raid0_personality.head);
833 }
834
835 module_init(raid0_init);
836 module_exit(raid0_exit);
837 MODULE_LICENSE("GPL");
838 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
839 MODULE_ALIAS("md-personality-2"); /* RAID0 */
840 MODULE_ALIAS("md-raid0");
841 MODULE_ALIAS("md-level-0");
842