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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");
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
9 RAID-0 management functions.
10
11 This program is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 2, or (at your option)
14 any later version.
15
16 You should have received a copy of the GNU General Public License
17 (for example /usr/src/linux/COPYING); if not, write to the Free
18 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19*/
20
21#include <linux/blkdev.h>
22#include <linux/seq_file.h>
23#include <linux/slab.h>
24#include "md.h"
25#include "raid0.h"
26#include "raid5.h"
27
28static int raid0_congested(void *data, int bits)
29{
30 mddev_t *mddev = data;
31 raid0_conf_t *conf = mddev->private;
32 mdk_rdev_t **devlist = conf->devlist;
33 int raid_disks = conf->strip_zone[0].nb_dev;
34 int i, ret = 0;
35
36 if (mddev_congested(mddev, bits))
37 return 1;
38
39 for (i = 0; i < raid_disks && !ret ; i++) {
40 struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
41
42 ret |= bdi_congested(&q->backing_dev_info, bits);
43 }
44 return ret;
45}
46
47/*
48 * inform the user of the raid configuration
49*/
50static void dump_zones(mddev_t *mddev)
51{
52 int j, k, h;
53 sector_t zone_size = 0;
54 sector_t zone_start = 0;
55 char b[BDEVNAME_SIZE];
56 raid0_conf_t *conf = mddev->private;
57 int raid_disks = conf->strip_zone[0].nb_dev;
58 printk(KERN_INFO "******* %s configuration *********\n",
59 mdname(mddev));
60 h = 0;
61 for (j = 0; j < conf->nr_strip_zones; j++) {
62 printk(KERN_INFO "zone%d=[", j);
63 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
64 printk(KERN_CONT "%s/",
65 bdevname(conf->devlist[j*raid_disks
66 + k]->bdev, b));
67 printk(KERN_CONT "]\n");
68
69 zone_size = conf->strip_zone[j].zone_end - zone_start;
70 printk(KERN_INFO " zone offset=%llukb "
71 "device offset=%llukb size=%llukb\n",
72 (unsigned long long)zone_start>>1,
73 (unsigned long long)conf->strip_zone[j].dev_start>>1,
74 (unsigned long long)zone_size>>1);
75 zone_start = conf->strip_zone[j].zone_end;
76 }
77 printk(KERN_INFO "**********************************\n\n");
78}
79
80static int create_strip_zones(mddev_t *mddev, raid0_conf_t **private_conf)
81{
82 int i, c, err;
83 sector_t curr_zone_end, sectors;
84 mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev, **dev;
85 struct strip_zone *zone;
86 int cnt;
87 char b[BDEVNAME_SIZE];
88 raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
89
90 if (!conf)
91 return -ENOMEM;
92 list_for_each_entry(rdev1, &mddev->disks, same_set) {
93 printk(KERN_INFO "md/raid0:%s: looking at %s\n",
94 mdname(mddev),
95 bdevname(rdev1->bdev, b));
96 c = 0;
97
98 /* round size to chunk_size */
99 sectors = rdev1->sectors;
100 sector_div(sectors, mddev->chunk_sectors);
101 rdev1->sectors = sectors * mddev->chunk_sectors;
102
103 list_for_each_entry(rdev2, &mddev->disks, same_set) {
104 printk(KERN_INFO "md/raid0:%s: comparing %s(%llu)",
105 mdname(mddev),
106 bdevname(rdev1->bdev,b),
107 (unsigned long long)rdev1->sectors);
108 printk(KERN_CONT " with %s(%llu)\n",
109 bdevname(rdev2->bdev,b),
110 (unsigned long long)rdev2->sectors);
111 if (rdev2 == rdev1) {
112 printk(KERN_INFO "md/raid0:%s: END\n",
113 mdname(mddev));
114 break;
115 }
116 if (rdev2->sectors == rdev1->sectors) {
117 /*
118 * Not unique, don't count it as a new
119 * group
120 */
121 printk(KERN_INFO "md/raid0:%s: EQUAL\n",
122 mdname(mddev));
123 c = 1;
124 break;
125 }
126 printk(KERN_INFO "md/raid0:%s: NOT EQUAL\n",
127 mdname(mddev));
128 }
129 if (!c) {
130 printk(KERN_INFO "md/raid0:%s: ==> UNIQUE\n",
131 mdname(mddev));
132 conf->nr_strip_zones++;
133 printk(KERN_INFO "md/raid0:%s: %d zones\n",
134 mdname(mddev), conf->nr_strip_zones);
135 }
136 }
137 printk(KERN_INFO "md/raid0:%s: FINAL %d zones\n",
138 mdname(mddev), conf->nr_strip_zones);
139 err = -ENOMEM;
140 conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
141 conf->nr_strip_zones, GFP_KERNEL);
142 if (!conf->strip_zone)
143 goto abort;
144 conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
145 conf->nr_strip_zones*mddev->raid_disks,
146 GFP_KERNEL);
147 if (!conf->devlist)
148 goto abort;
149
150 /* The first zone must contain all devices, so here we check that
151 * there is a proper alignment of slots to devices and find them all
152 */
153 zone = &conf->strip_zone[0];
154 cnt = 0;
155 smallest = NULL;
156 dev = conf->devlist;
157 err = -EINVAL;
158 list_for_each_entry(rdev1, &mddev->disks, same_set) {
159 int j = rdev1->raid_disk;
160
161 if (mddev->level == 10) {
162 /* taking over a raid10-n2 array */
163 j /= 2;
164 rdev1->new_raid_disk = j;
165 }
166
167 if (mddev->level == 1) {
168 /* taiking over a raid1 array-
169 * we have only one active disk
170 */
171 j = 0;
172 rdev1->new_raid_disk = j;
173 }
174
175 if (j < 0 || j >= mddev->raid_disks) {
176 printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
177 "aborting!\n", mdname(mddev), j);
178 goto abort;
179 }
180 if (dev[j]) {
181 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
182 "aborting!\n", mdname(mddev), j);
183 goto abort;
184 }
185 dev[j] = rdev1;
186
187 disk_stack_limits(mddev->gendisk, rdev1->bdev,
188 rdev1->data_offset << 9);
189 /* as we don't honour merge_bvec_fn, we must never risk
190 * violating it, so limit ->max_segments to 1, lying within
191 * a single page.
192 */
193
194 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) {
195 blk_queue_max_segments(mddev->queue, 1);
196 blk_queue_segment_boundary(mddev->queue,
197 PAGE_CACHE_SIZE - 1);
198 }
199 if (!smallest || (rdev1->sectors < smallest->sectors))
200 smallest = rdev1;
201 cnt++;
202 }
203 if (cnt != mddev->raid_disks) {
204 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - "
205 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks);
206 goto abort;
207 }
208 zone->nb_dev = cnt;
209 zone->zone_end = smallest->sectors * cnt;
210
211 curr_zone_end = zone->zone_end;
212
213 /* now do the other zones */
214 for (i = 1; i < conf->nr_strip_zones; i++)
215 {
216 int j;
217
218 zone = conf->strip_zone + i;
219 dev = conf->devlist + i * mddev->raid_disks;
220
221 printk(KERN_INFO "md/raid0:%s: zone %d\n",
222 mdname(mddev), i);
223 zone->dev_start = smallest->sectors;
224 smallest = NULL;
225 c = 0;
226
227 for (j=0; j<cnt; j++) {
228 rdev = conf->devlist[j];
229 printk(KERN_INFO "md/raid0:%s: checking %s ...",
230 mdname(mddev),
231 bdevname(rdev->bdev, b));
232 if (rdev->sectors <= zone->dev_start) {
233 printk(KERN_CONT " nope.\n");
234 continue;
235 }
236 printk(KERN_CONT " contained as device %d\n", c);
237 dev[c] = rdev;
238 c++;
239 if (!smallest || rdev->sectors < smallest->sectors) {
240 smallest = rdev;
241 printk(KERN_INFO "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 printk(KERN_INFO "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 printk(KERN_INFO "md/raid0:%s: current zone start: %llu\n",
257 mdname(mddev),
258 (unsigned long long)smallest->sectors);
259 }
260 mddev->queue->backing_dev_info.congested_fn = raid0_congested;
261 mddev->queue->backing_dev_info.congested_data = mddev;
262
263 /*
264 * now since we have the hard sector sizes, we can make sure
265 * chunk size is a multiple of that sector size
266 */
267 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
268 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
269 mdname(mddev),
270 mddev->chunk_sectors << 9);
271 goto abort;
272 }
273
274 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
275 blk_queue_io_opt(mddev->queue,
276 (mddev->chunk_sectors << 9) * mddev->raid_disks);
277
278 printk(KERN_INFO "md/raid0:%s: done.\n", mdname(mddev));
279 *private_conf = conf;
280
281 return 0;
282abort:
283 kfree(conf->strip_zone);
284 kfree(conf->devlist);
285 kfree(conf);
286 *private_conf = NULL;
287 return err;
288}
289
290/**
291 * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
292 * @q: request queue
293 * @bvm: properties of new bio
294 * @biovec: the request that could be merged to it.
295 *
296 * Return amount of bytes we can accept at this offset
297 */
298static int raid0_mergeable_bvec(struct request_queue *q,
299 struct bvec_merge_data *bvm,
300 struct bio_vec *biovec)
301{
302 mddev_t *mddev = q->queuedata;
303 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
304 int max;
305 unsigned int chunk_sectors = mddev->chunk_sectors;
306 unsigned int bio_sectors = bvm->bi_size >> 9;
307
308 if (is_power_of_2(chunk_sectors))
309 max = (chunk_sectors - ((sector & (chunk_sectors-1))
310 + bio_sectors)) << 9;
311 else
312 max = (chunk_sectors - (sector_div(sector, chunk_sectors)
313 + bio_sectors)) << 9;
314 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
315 if (max <= biovec->bv_len && bio_sectors == 0)
316 return biovec->bv_len;
317 else
318 return max;
319}
320
321static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks)
322{
323 sector_t array_sectors = 0;
324 mdk_rdev_t *rdev;
325
326 WARN_ONCE(sectors || raid_disks,
327 "%s does not support generic reshape\n", __func__);
328
329 list_for_each_entry(rdev, &mddev->disks, same_set)
330 array_sectors += rdev->sectors;
331
332 return array_sectors;
333}
334
335static int raid0_run(mddev_t *mddev)
336{
337 raid0_conf_t *conf;
338 int ret;
339
340 if (mddev->chunk_sectors == 0) {
341 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
342 mdname(mddev));
343 return -EINVAL;
344 }
345 if (md_check_no_bitmap(mddev))
346 return -EINVAL;
347 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
348
349 /* if private is not null, we are here after takeover */
350 if (mddev->private == NULL) {
351 ret = create_strip_zones(mddev, &conf);
352 if (ret < 0)
353 return ret;
354 mddev->private = conf;
355 }
356 conf = mddev->private;
357
358 /* calculate array device size */
359 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
360
361 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
362 mdname(mddev),
363 (unsigned long long)mddev->array_sectors);
364 /* calculate the max read-ahead size.
365 * For read-ahead of large files to be effective, we need to
366 * readahead at least twice a whole stripe. i.e. number of devices
367 * multiplied by chunk size times 2.
368 * If an individual device has an ra_pages greater than the
369 * chunk size, then we will not drive that device as hard as it
370 * wants. We consider this a configuration error: a larger
371 * chunksize should be used in that case.
372 */
373 {
374 int stripe = mddev->raid_disks *
375 (mddev->chunk_sectors << 9) / PAGE_SIZE;
376 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
377 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
378 }
379
380 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
381 dump_zones(mddev);
382 return md_integrity_register(mddev);
383}
384
385static int raid0_stop(mddev_t *mddev)
386{
387 raid0_conf_t *conf = mddev->private;
388
389 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
390 kfree(conf->strip_zone);
391 kfree(conf->devlist);
392 kfree(conf);
393 mddev->private = NULL;
394 return 0;
395}
396
397/* Find the zone which holds a particular offset
398 * Update *sectorp to be an offset in that zone
399 */
400static struct strip_zone *find_zone(struct raid0_private_data *conf,
401 sector_t *sectorp)
402{
403 int i;
404 struct strip_zone *z = conf->strip_zone;
405 sector_t sector = *sectorp;
406
407 for (i = 0; i < conf->nr_strip_zones; i++)
408 if (sector < z[i].zone_end) {
409 if (i)
410 *sectorp = sector - z[i-1].zone_end;
411 return z + i;
412 }
413 BUG();
414}
415
416/*
417 * remaps the bio to the target device. we separate two flows.
418 * power 2 flow and a general flow for the sake of perfromance
419*/
420static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone,
421 sector_t sector, sector_t *sector_offset)
422{
423 unsigned int sect_in_chunk;
424 sector_t chunk;
425 raid0_conf_t *conf = mddev->private;
426 int raid_disks = conf->strip_zone[0].nb_dev;
427 unsigned int chunk_sects = mddev->chunk_sectors;
428
429 if (is_power_of_2(chunk_sects)) {
430 int chunksect_bits = ffz(~chunk_sects);
431 /* find the sector offset inside the chunk */
432 sect_in_chunk = sector & (chunk_sects - 1);
433 sector >>= chunksect_bits;
434 /* chunk in zone */
435 chunk = *sector_offset;
436 /* quotient is the chunk in real device*/
437 sector_div(chunk, zone->nb_dev << chunksect_bits);
438 } else{
439 sect_in_chunk = sector_div(sector, chunk_sects);
440 chunk = *sector_offset;
441 sector_div(chunk, chunk_sects * zone->nb_dev);
442 }
443 /*
444 * position the bio over the real device
445 * real sector = chunk in device + starting of zone
446 * + the position in the chunk
447 */
448 *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
449 return conf->devlist[(zone - conf->strip_zone)*raid_disks
450 + sector_div(sector, zone->nb_dev)];
451}
452
453/*
454 * Is io distribute over 1 or more chunks ?
455*/
456static inline int is_io_in_chunk_boundary(mddev_t *mddev,
457 unsigned int chunk_sects, struct bio *bio)
458{
459 if (likely(is_power_of_2(chunk_sects))) {
460 return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
461 + (bio->bi_size >> 9));
462 } else{
463 sector_t sector = bio->bi_sector;
464 return chunk_sects >= (sector_div(sector, chunk_sects)
465 + (bio->bi_size >> 9));
466 }
467}
468
469static int raid0_make_request(mddev_t *mddev, struct bio *bio)
470{
471 unsigned int chunk_sects;
472 sector_t sector_offset;
473 struct strip_zone *zone;
474 mdk_rdev_t *tmp_dev;
475
476 if (unlikely(bio->bi_rw & REQ_FLUSH)) {
477 md_flush_request(mddev, bio);
478 return 0;
479 }
480
481 chunk_sects = mddev->chunk_sectors;
482 if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) {
483 sector_t sector = bio->bi_sector;
484 struct bio_pair *bp;
485 /* Sanity check -- queue functions should prevent this happening */
486 if (bio->bi_vcnt != 1 ||
487 bio->bi_idx != 0)
488 goto bad_map;
489 /* This is a one page bio that upper layers
490 * refuse to split for us, so we need to split it.
491 */
492 if (likely(is_power_of_2(chunk_sects)))
493 bp = bio_split(bio, chunk_sects - (sector &
494 (chunk_sects-1)));
495 else
496 bp = bio_split(bio, chunk_sects -
497 sector_div(sector, chunk_sects));
498 if (raid0_make_request(mddev, &bp->bio1))
499 generic_make_request(&bp->bio1);
500 if (raid0_make_request(mddev, &bp->bio2))
501 generic_make_request(&bp->bio2);
502
503 bio_pair_release(bp);
504 return 0;
505 }
506
507 sector_offset = bio->bi_sector;
508 zone = find_zone(mddev->private, §or_offset);
509 tmp_dev = map_sector(mddev, zone, bio->bi_sector,
510 §or_offset);
511 bio->bi_bdev = tmp_dev->bdev;
512 bio->bi_sector = sector_offset + zone->dev_start +
513 tmp_dev->data_offset;
514 /*
515 * Let the main block layer submit the IO and resolve recursion:
516 */
517 return 1;
518
519bad_map:
520 printk("md/raid0:%s: make_request bug: can't convert block across chunks"
521 " or bigger than %dk %llu %d\n",
522 mdname(mddev), chunk_sects / 2,
523 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
524
525 bio_io_error(bio);
526 return 0;
527}
528
529static void raid0_status(struct seq_file *seq, mddev_t *mddev)
530{
531#undef MD_DEBUG
532#ifdef MD_DEBUG
533 int j, k, h;
534 char b[BDEVNAME_SIZE];
535 raid0_conf_t *conf = mddev->private;
536 int raid_disks = conf->strip_zone[0].nb_dev;
537
538 sector_t zone_size;
539 sector_t zone_start = 0;
540 h = 0;
541
542 for (j = 0; j < conf->nr_strip_zones; j++) {
543 seq_printf(seq, " z%d", j);
544 seq_printf(seq, "=[");
545 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
546 seq_printf(seq, "%s/", bdevname(
547 conf->devlist[j*raid_disks + k]
548 ->bdev, b));
549
550 zone_size = conf->strip_zone[j].zone_end - zone_start;
551 seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n",
552 (unsigned long long)zone_start>>1,
553 (unsigned long long)conf->strip_zone[j].dev_start>>1,
554 (unsigned long long)zone_size>>1);
555 zone_start = conf->strip_zone[j].zone_end;
556 }
557#endif
558 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
559 return;
560}
561
562static void *raid0_takeover_raid45(mddev_t *mddev)
563{
564 mdk_rdev_t *rdev;
565 raid0_conf_t *priv_conf;
566
567 if (mddev->degraded != 1) {
568 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
569 mdname(mddev),
570 mddev->degraded);
571 return ERR_PTR(-EINVAL);
572 }
573
574 list_for_each_entry(rdev, &mddev->disks, same_set) {
575 /* check slot number for a disk */
576 if (rdev->raid_disk == mddev->raid_disks-1) {
577 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
578 mdname(mddev));
579 return ERR_PTR(-EINVAL);
580 }
581 }
582
583 /* Set new parameters */
584 mddev->new_level = 0;
585 mddev->new_layout = 0;
586 mddev->new_chunk_sectors = mddev->chunk_sectors;
587 mddev->raid_disks--;
588 mddev->delta_disks = -1;
589 /* make sure it will be not marked as dirty */
590 mddev->recovery_cp = MaxSector;
591
592 create_strip_zones(mddev, &priv_conf);
593 return priv_conf;
594}
595
596static void *raid0_takeover_raid10(mddev_t *mddev)
597{
598 raid0_conf_t *priv_conf;
599
600 /* Check layout:
601 * - far_copies must be 1
602 * - near_copies must be 2
603 * - disks number must be even
604 * - all mirrors must be already degraded
605 */
606 if (mddev->layout != ((1 << 8) + 2)) {
607 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n",
608 mdname(mddev),
609 mddev->layout);
610 return ERR_PTR(-EINVAL);
611 }
612 if (mddev->raid_disks & 1) {
613 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n",
614 mdname(mddev));
615 return ERR_PTR(-EINVAL);
616 }
617 if (mddev->degraded != (mddev->raid_disks>>1)) {
618 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n",
619 mdname(mddev));
620 return ERR_PTR(-EINVAL);
621 }
622
623 /* Set new parameters */
624 mddev->new_level = 0;
625 mddev->new_layout = 0;
626 mddev->new_chunk_sectors = mddev->chunk_sectors;
627 mddev->delta_disks = - mddev->raid_disks / 2;
628 mddev->raid_disks += mddev->delta_disks;
629 mddev->degraded = 0;
630 /* make sure it will be not marked as dirty */
631 mddev->recovery_cp = MaxSector;
632
633 create_strip_zones(mddev, &priv_conf);
634 return priv_conf;
635}
636
637static void *raid0_takeover_raid1(mddev_t *mddev)
638{
639 raid0_conf_t *priv_conf;
640
641 /* Check layout:
642 * - (N - 1) mirror drives must be already faulty
643 */
644 if ((mddev->raid_disks - 1) != mddev->degraded) {
645 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
646 mdname(mddev));
647 return ERR_PTR(-EINVAL);
648 }
649
650 /* Set new parameters */
651 mddev->new_level = 0;
652 mddev->new_layout = 0;
653 mddev->new_chunk_sectors = 128; /* by default set chunk size to 64k */
654 mddev->delta_disks = 1 - mddev->raid_disks;
655 mddev->raid_disks = 1;
656 /* make sure it will be not marked as dirty */
657 mddev->recovery_cp = MaxSector;
658
659 create_strip_zones(mddev, &priv_conf);
660 return priv_conf;
661}
662
663static void *raid0_takeover(mddev_t *mddev)
664{
665 /* raid0 can take over:
666 * raid4 - if all data disks are active.
667 * raid5 - providing it is Raid4 layout and one disk is faulty
668 * raid10 - assuming we have all necessary active disks
669 * raid1 - with (N -1) mirror drives faulty
670 */
671 if (mddev->level == 4)
672 return raid0_takeover_raid45(mddev);
673
674 if (mddev->level == 5) {
675 if (mddev->layout == ALGORITHM_PARITY_N)
676 return raid0_takeover_raid45(mddev);
677
678 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
679 mdname(mddev), ALGORITHM_PARITY_N);
680 }
681
682 if (mddev->level == 10)
683 return raid0_takeover_raid10(mddev);
684
685 if (mddev->level == 1)
686 return raid0_takeover_raid1(mddev);
687
688 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n",
689 mddev->level);
690
691 return ERR_PTR(-EINVAL);
692}
693
694static void raid0_quiesce(mddev_t *mddev, int state)
695{
696}
697
698static struct mdk_personality raid0_personality=
699{
700 .name = "raid0",
701 .level = 0,
702 .owner = THIS_MODULE,
703 .make_request = raid0_make_request,
704 .run = raid0_run,
705 .stop = raid0_stop,
706 .status = raid0_status,
707 .size = raid0_size,
708 .takeover = raid0_takeover,
709 .quiesce = raid0_quiesce,
710};
711
712static int __init raid0_init (void)
713{
714 return register_md_personality (&raid0_personality);
715}
716
717static void raid0_exit (void)
718{
719 unregister_md_personality (&raid0_personality);
720}
721
722module_init(raid0_init);
723module_exit(raid0_exit);
724MODULE_LICENSE("GPL");
725MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
726MODULE_ALIAS("md-personality-2"); /* RAID0 */
727MODULE_ALIAS("md-raid0");
728MODULE_ALIAS("md-level-0");