2 raid0.c : Multiple Devices driver for Linux
3 Copyright (C) 1994-96 Marc ZYNGIER
4 <zyngier@ufr-info-p7.ibp.fr> or
6 Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
9 RAID-0 management functions.
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)
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.
21 #include <linux/blkdev.h>
22 #include <linux/seq_file.h>
23 #include <linux/module.h>
24 #include <linux/slab.h>
29 static int raid0_congested(void *data
, int bits
)
31 struct mddev
*mddev
= data
;
32 struct r0conf
*conf
= mddev
->private;
33 struct md_rdev
**devlist
= conf
->devlist
;
34 int raid_disks
= conf
->strip_zone
[0].nb_dev
;
37 if (mddev_congested(mddev
, bits
))
40 for (i
= 0; i
< raid_disks
&& !ret
; i
++) {
41 struct request_queue
*q
= bdev_get_queue(devlist
[i
]->bdev
);
43 ret
|= bdi_congested(&q
->backing_dev_info
, bits
);
49 * inform the user of the raid configuration
51 static void dump_zones(struct mddev
*mddev
)
54 sector_t zone_size
= 0;
55 sector_t zone_start
= 0;
56 char b
[BDEVNAME_SIZE
];
57 struct r0conf
*conf
= mddev
->private;
58 int raid_disks
= conf
->strip_zone
[0].nb_dev
;
59 printk(KERN_INFO
"md: RAID0 configuration for %s - %d zone%s\n",
61 conf
->nr_strip_zones
, conf
->nr_strip_zones
==1?"":"s");
62 for (j
= 0; j
< conf
->nr_strip_zones
; j
++) {
63 printk(KERN_INFO
"md: zone%d=[", j
);
64 for (k
= 0; k
< conf
->strip_zone
[j
].nb_dev
; k
++)
65 printk(KERN_CONT
"%s%s", k
?"/":"",
66 bdevname(conf
->devlist
[j
*raid_disks
68 printk(KERN_CONT
"]\n");
70 zone_size
= conf
->strip_zone
[j
].zone_end
- zone_start
;
71 printk(KERN_INFO
" zone-offset=%10lluKB, "
72 "device-offset=%10lluKB, size=%10lluKB\n",
73 (unsigned long long)zone_start
>>1,
74 (unsigned long long)conf
->strip_zone
[j
].dev_start
>>1,
75 (unsigned long long)zone_size
>>1);
76 zone_start
= conf
->strip_zone
[j
].zone_end
;
78 printk(KERN_INFO
"\n");
81 static int create_strip_zones(struct mddev
*mddev
, struct r0conf
**private_conf
)
84 sector_t curr_zone_end
, sectors
;
85 struct md_rdev
*smallest
, *rdev1
, *rdev2
, *rdev
, **dev
;
86 struct strip_zone
*zone
;
88 char b
[BDEVNAME_SIZE
];
89 char b2
[BDEVNAME_SIZE
];
90 struct r0conf
*conf
= kzalloc(sizeof(*conf
), GFP_KERNEL
);
94 rdev_for_each(rdev1
, mddev
) {
95 pr_debug("md/raid0:%s: looking at %s\n",
97 bdevname(rdev1
->bdev
, b
));
100 /* round size to chunk_size */
101 sectors
= rdev1
->sectors
;
102 sector_div(sectors
, mddev
->chunk_sectors
);
103 rdev1
->sectors
= sectors
* mddev
->chunk_sectors
;
105 rdev_for_each(rdev2
, mddev
) {
106 pr_debug("md/raid0:%s: comparing %s(%llu)"
109 bdevname(rdev1
->bdev
,b
),
110 (unsigned long long)rdev1
->sectors
,
111 bdevname(rdev2
->bdev
,b2
),
112 (unsigned long long)rdev2
->sectors
);
113 if (rdev2
== rdev1
) {
114 pr_debug("md/raid0:%s: END\n",
118 if (rdev2
->sectors
== rdev1
->sectors
) {
120 * Not unique, don't count it as a new
123 pr_debug("md/raid0:%s: EQUAL\n",
128 pr_debug("md/raid0:%s: NOT EQUAL\n",
132 pr_debug("md/raid0:%s: ==> UNIQUE\n",
134 conf
->nr_strip_zones
++;
135 pr_debug("md/raid0:%s: %d zones\n",
136 mdname(mddev
), conf
->nr_strip_zones
);
139 pr_debug("md/raid0:%s: FINAL %d zones\n",
140 mdname(mddev
), conf
->nr_strip_zones
);
142 conf
->strip_zone
= kzalloc(sizeof(struct strip_zone
)*
143 conf
->nr_strip_zones
, GFP_KERNEL
);
144 if (!conf
->strip_zone
)
146 conf
->devlist
= kzalloc(sizeof(struct md_rdev
*)*
147 conf
->nr_strip_zones
*mddev
->raid_disks
,
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
155 zone
= &conf
->strip_zone
[0];
160 rdev_for_each(rdev1
, mddev
) {
161 int j
= rdev1
->raid_disk
;
163 if (mddev
->level
== 10) {
164 /* taking over a raid10-n2 array */
166 rdev1
->new_raid_disk
= j
;
169 if (mddev
->level
== 1) {
170 /* taiking over a raid1 array-
171 * we have only one active disk
174 rdev1
->new_raid_disk
= j
;
177 if (j
< 0 || j
>= mddev
->raid_disks
) {
178 printk(KERN_ERR
"md/raid0:%s: bad disk number %d - "
179 "aborting!\n", mdname(mddev
), j
);
183 printk(KERN_ERR
"md/raid0:%s: multiple devices for %d - "
184 "aborting!\n", mdname(mddev
), j
);
189 disk_stack_limits(mddev
->gendisk
, rdev1
->bdev
,
190 rdev1
->data_offset
<< 9);
192 if (rdev1
->bdev
->bd_disk
->queue
->merge_bvec_fn
)
193 conf
->has_merge_bvec
= 1;
195 if (!smallest
|| (rdev1
->sectors
< smallest
->sectors
))
199 if (cnt
!= mddev
->raid_disks
) {
200 printk(KERN_ERR
"md/raid0:%s: too few disks (%d of %d) - "
201 "aborting!\n", mdname(mddev
), cnt
, mddev
->raid_disks
);
205 zone
->zone_end
= smallest
->sectors
* cnt
;
207 curr_zone_end
= zone
->zone_end
;
209 /* now do the other zones */
210 for (i
= 1; i
< conf
->nr_strip_zones
; i
++)
214 zone
= conf
->strip_zone
+ i
;
215 dev
= conf
->devlist
+ i
* mddev
->raid_disks
;
217 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev
), i
);
218 zone
->dev_start
= smallest
->sectors
;
222 for (j
=0; j
<cnt
; j
++) {
223 rdev
= conf
->devlist
[j
];
224 if (rdev
->sectors
<= zone
->dev_start
) {
225 pr_debug("md/raid0:%s: checking %s ... nope\n",
227 bdevname(rdev
->bdev
, b
));
230 pr_debug("md/raid0:%s: checking %s ..."
231 " contained as device %d\n",
233 bdevname(rdev
->bdev
, b
), c
);
236 if (!smallest
|| rdev
->sectors
< smallest
->sectors
) {
238 pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
240 (unsigned long long)rdev
->sectors
);
245 sectors
= (smallest
->sectors
- zone
->dev_start
) * c
;
246 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
248 zone
->nb_dev
, (unsigned long long)sectors
);
250 curr_zone_end
+= sectors
;
251 zone
->zone_end
= curr_zone_end
;
253 pr_debug("md/raid0:%s: current zone start: %llu\n",
255 (unsigned long long)smallest
->sectors
);
257 mddev
->queue
->backing_dev_info
.congested_fn
= raid0_congested
;
258 mddev
->queue
->backing_dev_info
.congested_data
= mddev
;
261 * now since we have the hard sector sizes, we can make sure
262 * chunk size is a multiple of that sector size
264 if ((mddev
->chunk_sectors
<< 9) % queue_logical_block_size(mddev
->queue
)) {
265 printk(KERN_ERR
"md/raid0:%s: chunk_size of %d not valid\n",
267 mddev
->chunk_sectors
<< 9);
271 blk_queue_io_min(mddev
->queue
, mddev
->chunk_sectors
<< 9);
272 blk_queue_io_opt(mddev
->queue
,
273 (mddev
->chunk_sectors
<< 9) * mddev
->raid_disks
);
275 pr_debug("md/raid0:%s: done.\n", mdname(mddev
));
276 *private_conf
= conf
;
280 kfree(conf
->strip_zone
);
281 kfree(conf
->devlist
);
283 *private_conf
= NULL
;
287 /* Find the zone which holds a particular offset
288 * Update *sectorp to be an offset in that zone
290 static struct strip_zone
*find_zone(struct r0conf
*conf
,
294 struct strip_zone
*z
= conf
->strip_zone
;
295 sector_t sector
= *sectorp
;
297 for (i
= 0; i
< conf
->nr_strip_zones
; i
++)
298 if (sector
< z
[i
].zone_end
) {
300 *sectorp
= sector
- z
[i
-1].zone_end
;
307 * remaps the bio to the target device. we separate two flows.
308 * power 2 flow and a general flow for the sake of perfromance
310 static struct md_rdev
*map_sector(struct mddev
*mddev
, struct strip_zone
*zone
,
311 sector_t sector
, sector_t
*sector_offset
)
313 unsigned int sect_in_chunk
;
315 struct r0conf
*conf
= mddev
->private;
316 int raid_disks
= conf
->strip_zone
[0].nb_dev
;
317 unsigned int chunk_sects
= mddev
->chunk_sectors
;
319 if (is_power_of_2(chunk_sects
)) {
320 int chunksect_bits
= ffz(~chunk_sects
);
321 /* find the sector offset inside the chunk */
322 sect_in_chunk
= sector
& (chunk_sects
- 1);
323 sector
>>= chunksect_bits
;
325 chunk
= *sector_offset
;
326 /* quotient is the chunk in real device*/
327 sector_div(chunk
, zone
->nb_dev
<< chunksect_bits
);
329 sect_in_chunk
= sector_div(sector
, chunk_sects
);
330 chunk
= *sector_offset
;
331 sector_div(chunk
, chunk_sects
* zone
->nb_dev
);
334 * position the bio over the real device
335 * real sector = chunk in device + starting of zone
336 * + the position in the chunk
338 *sector_offset
= (chunk
* chunk_sects
) + sect_in_chunk
;
339 return conf
->devlist
[(zone
- conf
->strip_zone
)*raid_disks
340 + sector_div(sector
, zone
->nb_dev
)];
344 * raid0_mergeable_bvec -- tell bio layer if two requests can be merged
346 * @bvm: properties of new bio
347 * @biovec: the request that could be merged to it.
349 * Return amount of bytes we can accept at this offset
351 static int raid0_mergeable_bvec(struct request_queue
*q
,
352 struct bvec_merge_data
*bvm
,
353 struct bio_vec
*biovec
)
355 struct mddev
*mddev
= q
->queuedata
;
356 struct r0conf
*conf
= mddev
->private;
357 sector_t sector
= bvm
->bi_sector
+ get_start_sect(bvm
->bi_bdev
);
358 sector_t sector_offset
= sector
;
360 unsigned int chunk_sectors
= mddev
->chunk_sectors
;
361 unsigned int bio_sectors
= bvm
->bi_size
>> 9;
362 struct strip_zone
*zone
;
363 struct md_rdev
*rdev
;
364 struct request_queue
*subq
;
366 if (is_power_of_2(chunk_sectors
))
367 max
= (chunk_sectors
- ((sector
& (chunk_sectors
-1))
368 + bio_sectors
)) << 9;
370 max
= (chunk_sectors
- (sector_div(sector
, chunk_sectors
)
371 + bio_sectors
)) << 9;
373 max
= 0; /* bio_add cannot handle a negative return */
374 if (max
<= biovec
->bv_len
&& bio_sectors
== 0)
375 return biovec
->bv_len
;
376 if (max
< biovec
->bv_len
)
377 /* too small already, no need to check further */
379 if (!conf
->has_merge_bvec
)
382 /* May need to check subordinate device */
383 sector
= sector_offset
;
384 zone
= find_zone(mddev
->private, §or_offset
);
385 rdev
= map_sector(mddev
, zone
, sector
, §or_offset
);
386 subq
= bdev_get_queue(rdev
->bdev
);
387 if (subq
->merge_bvec_fn
) {
388 bvm
->bi_bdev
= rdev
->bdev
;
389 bvm
->bi_sector
= sector_offset
+ zone
->dev_start
+
391 return min(max
, subq
->merge_bvec_fn(subq
, bvm
, biovec
));
396 static sector_t
raid0_size(struct mddev
*mddev
, sector_t sectors
, int raid_disks
)
398 sector_t array_sectors
= 0;
399 struct md_rdev
*rdev
;
401 WARN_ONCE(sectors
|| raid_disks
,
402 "%s does not support generic reshape\n", __func__
);
404 rdev_for_each(rdev
, mddev
)
405 array_sectors
+= rdev
->sectors
;
407 return array_sectors
;
410 static int raid0_run(struct mddev
*mddev
)
415 if (mddev
->chunk_sectors
== 0) {
416 printk(KERN_ERR
"md/raid0:%s: chunk size must be set.\n",
420 if (md_check_no_bitmap(mddev
))
422 blk_queue_max_hw_sectors(mddev
->queue
, mddev
->chunk_sectors
);
424 /* if private is not null, we are here after takeover */
425 if (mddev
->private == NULL
) {
426 ret
= create_strip_zones(mddev
, &conf
);
429 mddev
->private = conf
;
431 conf
= mddev
->private;
433 /* calculate array device size */
434 md_set_array_sectors(mddev
, raid0_size(mddev
, 0, 0));
436 printk(KERN_INFO
"md/raid0:%s: md_size is %llu sectors.\n",
438 (unsigned long long)mddev
->array_sectors
);
439 /* calculate the max read-ahead size.
440 * For read-ahead of large files to be effective, we need to
441 * readahead at least twice a whole stripe. i.e. number of devices
442 * multiplied by chunk size times 2.
443 * If an individual device has an ra_pages greater than the
444 * chunk size, then we will not drive that device as hard as it
445 * wants. We consider this a configuration error: a larger
446 * chunksize should be used in that case.
449 int stripe
= mddev
->raid_disks
*
450 (mddev
->chunk_sectors
<< 9) / PAGE_SIZE
;
451 if (mddev
->queue
->backing_dev_info
.ra_pages
< 2* stripe
)
452 mddev
->queue
->backing_dev_info
.ra_pages
= 2* stripe
;
455 blk_queue_merge_bvec(mddev
->queue
, raid0_mergeable_bvec
);
457 return md_integrity_register(mddev
);
460 static int raid0_stop(struct mddev
*mddev
)
462 struct r0conf
*conf
= mddev
->private;
464 blk_sync_queue(mddev
->queue
); /* the unplug fn references 'conf'*/
465 kfree(conf
->strip_zone
);
466 kfree(conf
->devlist
);
468 mddev
->private = NULL
;
473 * Is io distribute over 1 or more chunks ?
475 static inline int is_io_in_chunk_boundary(struct mddev
*mddev
,
476 unsigned int chunk_sects
, struct bio
*bio
)
478 if (likely(is_power_of_2(chunk_sects
))) {
479 return chunk_sects
>= ((bio
->bi_sector
& (chunk_sects
-1))
480 + (bio
->bi_size
>> 9));
482 sector_t sector
= bio
->bi_sector
;
483 return chunk_sects
>= (sector_div(sector
, chunk_sects
)
484 + (bio
->bi_size
>> 9));
488 static void raid0_make_request(struct mddev
*mddev
, struct bio
*bio
)
490 unsigned int chunk_sects
;
491 sector_t sector_offset
;
492 struct strip_zone
*zone
;
493 struct md_rdev
*tmp_dev
;
495 if (unlikely(bio
->bi_rw
& REQ_FLUSH
)) {
496 md_flush_request(mddev
, bio
);
500 chunk_sects
= mddev
->chunk_sectors
;
501 if (unlikely(!is_io_in_chunk_boundary(mddev
, chunk_sects
, bio
))) {
502 sector_t sector
= bio
->bi_sector
;
504 /* Sanity check -- queue functions should prevent this happening */
505 if (bio
->bi_vcnt
!= 1 ||
508 /* This is a one page bio that upper layers
509 * refuse to split for us, so we need to split it.
511 if (likely(is_power_of_2(chunk_sects
)))
512 bp
= bio_split(bio
, chunk_sects
- (sector
&
515 bp
= bio_split(bio
, chunk_sects
-
516 sector_div(sector
, chunk_sects
));
517 raid0_make_request(mddev
, &bp
->bio1
);
518 raid0_make_request(mddev
, &bp
->bio2
);
519 bio_pair_release(bp
);
523 sector_offset
= bio
->bi_sector
;
524 zone
= find_zone(mddev
->private, §or_offset
);
525 tmp_dev
= map_sector(mddev
, zone
, bio
->bi_sector
,
527 bio
->bi_bdev
= tmp_dev
->bdev
;
528 bio
->bi_sector
= sector_offset
+ zone
->dev_start
+
529 tmp_dev
->data_offset
;
531 generic_make_request(bio
);
535 printk("md/raid0:%s: make_request bug: can't convert block across chunks"
536 " or bigger than %dk %llu %d\n",
537 mdname(mddev
), chunk_sects
/ 2,
538 (unsigned long long)bio
->bi_sector
, bio
->bi_size
>> 10);
544 static void raid0_status(struct seq_file
*seq
, struct mddev
*mddev
)
546 seq_printf(seq
, " %dk chunks", mddev
->chunk_sectors
/ 2);
550 static void *raid0_takeover_raid45(struct mddev
*mddev
)
552 struct md_rdev
*rdev
;
553 struct r0conf
*priv_conf
;
555 if (mddev
->degraded
!= 1) {
556 printk(KERN_ERR
"md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
559 return ERR_PTR(-EINVAL
);
562 rdev_for_each(rdev
, mddev
) {
563 /* check slot number for a disk */
564 if (rdev
->raid_disk
== mddev
->raid_disks
-1) {
565 printk(KERN_ERR
"md/raid0:%s: raid5 must have missing parity disk!\n",
567 return ERR_PTR(-EINVAL
);
571 /* Set new parameters */
572 mddev
->new_level
= 0;
573 mddev
->new_layout
= 0;
574 mddev
->new_chunk_sectors
= mddev
->chunk_sectors
;
576 mddev
->delta_disks
= -1;
577 /* make sure it will be not marked as dirty */
578 mddev
->recovery_cp
= MaxSector
;
580 create_strip_zones(mddev
, &priv_conf
);
584 static void *raid0_takeover_raid10(struct mddev
*mddev
)
586 struct r0conf
*priv_conf
;
589 * - far_copies must be 1
590 * - near_copies must be 2
591 * - disks number must be even
592 * - all mirrors must be already degraded
594 if (mddev
->layout
!= ((1 << 8) + 2)) {
595 printk(KERN_ERR
"md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n",
598 return ERR_PTR(-EINVAL
);
600 if (mddev
->raid_disks
& 1) {
601 printk(KERN_ERR
"md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n",
603 return ERR_PTR(-EINVAL
);
605 if (mddev
->degraded
!= (mddev
->raid_disks
>>1)) {
606 printk(KERN_ERR
"md/raid0:%s: All mirrors must be already degraded!\n",
608 return ERR_PTR(-EINVAL
);
611 /* Set new parameters */
612 mddev
->new_level
= 0;
613 mddev
->new_layout
= 0;
614 mddev
->new_chunk_sectors
= mddev
->chunk_sectors
;
615 mddev
->delta_disks
= - mddev
->raid_disks
/ 2;
616 mddev
->raid_disks
+= mddev
->delta_disks
;
618 /* make sure it will be not marked as dirty */
619 mddev
->recovery_cp
= MaxSector
;
621 create_strip_zones(mddev
, &priv_conf
);
625 static void *raid0_takeover_raid1(struct mddev
*mddev
)
627 struct r0conf
*priv_conf
;
630 * - (N - 1) mirror drives must be already faulty
632 if ((mddev
->raid_disks
- 1) != mddev
->degraded
) {
633 printk(KERN_ERR
"md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
635 return ERR_PTR(-EINVAL
);
638 /* Set new parameters */
639 mddev
->new_level
= 0;
640 mddev
->new_layout
= 0;
641 mddev
->new_chunk_sectors
= 128; /* by default set chunk size to 64k */
642 mddev
->delta_disks
= 1 - mddev
->raid_disks
;
643 mddev
->raid_disks
= 1;
644 /* make sure it will be not marked as dirty */
645 mddev
->recovery_cp
= MaxSector
;
647 create_strip_zones(mddev
, &priv_conf
);
651 static void *raid0_takeover(struct mddev
*mddev
)
653 /* raid0 can take over:
654 * raid4 - if all data disks are active.
655 * raid5 - providing it is Raid4 layout and one disk is faulty
656 * raid10 - assuming we have all necessary active disks
657 * raid1 - with (N -1) mirror drives faulty
659 if (mddev
->level
== 4)
660 return raid0_takeover_raid45(mddev
);
662 if (mddev
->level
== 5) {
663 if (mddev
->layout
== ALGORITHM_PARITY_N
)
664 return raid0_takeover_raid45(mddev
);
666 printk(KERN_ERR
"md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
667 mdname(mddev
), ALGORITHM_PARITY_N
);
670 if (mddev
->level
== 10)
671 return raid0_takeover_raid10(mddev
);
673 if (mddev
->level
== 1)
674 return raid0_takeover_raid1(mddev
);
676 printk(KERN_ERR
"Takeover from raid%i to raid0 not supported\n",
679 return ERR_PTR(-EINVAL
);
682 static void raid0_quiesce(struct mddev
*mddev
, int state
)
686 static struct md_personality raid0_personality
=
690 .owner
= THIS_MODULE
,
691 .make_request
= raid0_make_request
,
694 .status
= raid0_status
,
696 .takeover
= raid0_takeover
,
697 .quiesce
= raid0_quiesce
,
700 static int __init
raid0_init (void)
702 return register_md_personality (&raid0_personality
);
705 static void raid0_exit (void)
707 unregister_md_personality (&raid0_personality
);
710 module_init(raid0_init
);
711 module_exit(raid0_exit
);
712 MODULE_LICENSE("GPL");
713 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
714 MODULE_ALIAS("md-personality-2"); /* RAID0 */
715 MODULE_ALIAS("md-raid0");
716 MODULE_ALIAS("md-level-0");