| /* |
| raid0.c : Multiple Devices driver for Linux |
| Copyright (C) 1994-96 Marc ZYNGIER |
| <zyngier@ufr-info-p7.ibp.fr> or |
| <maz@gloups.fdn.fr> |
| Copyright (C) 1999, 2000 Ingo Molnar, Red Hat |
| |
| |
| RAID-0 management functions. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| You should have received a copy of the GNU General Public License |
| (for example /usr/src/linux/COPYING); if not, write to the Free |
| Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #include <linux/blkdev.h> |
| #include <linux/seq_file.h> |
| #include "md.h" |
| #include "raid0.h" |
| |
| static void raid0_unplug(struct request_queue *q) |
| { |
| mddev_t *mddev = q->queuedata; |
| raid0_conf_t *conf = mddev_to_conf(mddev); |
| mdk_rdev_t **devlist = conf->strip_zone[0].dev; |
| int i; |
| |
| for (i=0; i<mddev->raid_disks; i++) { |
| struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev); |
| |
| blk_unplug(r_queue); |
| } |
| } |
| |
| static int raid0_congested(void *data, int bits) |
| { |
| mddev_t *mddev = data; |
| raid0_conf_t *conf = mddev_to_conf(mddev); |
| mdk_rdev_t **devlist = conf->strip_zone[0].dev; |
| int i, ret = 0; |
| |
| for (i = 0; i < mddev->raid_disks && !ret ; i++) { |
| struct request_queue *q = bdev_get_queue(devlist[i]->bdev); |
| |
| ret |= bdi_congested(&q->backing_dev_info, bits); |
| } |
| return ret; |
| } |
| |
| |
| static int create_strip_zones (mddev_t *mddev) |
| { |
| int i, c, j; |
| sector_t current_start, curr_zone_start; |
| sector_t min_spacing; |
| raid0_conf_t *conf = mddev_to_conf(mddev); |
| mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev; |
| struct strip_zone *zone; |
| int cnt; |
| char b[BDEVNAME_SIZE]; |
| |
| /* |
| * The number of 'same size groups' |
| */ |
| conf->nr_strip_zones = 0; |
| |
| list_for_each_entry(rdev1, &mddev->disks, same_set) { |
| printk(KERN_INFO "raid0: looking at %s\n", |
| bdevname(rdev1->bdev,b)); |
| c = 0; |
| list_for_each_entry(rdev2, &mddev->disks, same_set) { |
| printk(KERN_INFO "raid0: comparing %s(%llu)", |
| bdevname(rdev1->bdev,b), |
| (unsigned long long)rdev1->sectors); |
| printk(KERN_INFO " with %s(%llu)\n", |
| bdevname(rdev2->bdev,b), |
| (unsigned long long)rdev2->sectors); |
| if (rdev2 == rdev1) { |
| printk(KERN_INFO "raid0: END\n"); |
| break; |
| } |
| if (rdev2->sectors == rdev1->sectors) { |
| /* |
| * Not unique, don't count it as a new |
| * group |
| */ |
| printk(KERN_INFO "raid0: EQUAL\n"); |
| c = 1; |
| break; |
| } |
| printk(KERN_INFO "raid0: NOT EQUAL\n"); |
| } |
| if (!c) { |
| printk(KERN_INFO "raid0: ==> UNIQUE\n"); |
| conf->nr_strip_zones++; |
| printk(KERN_INFO "raid0: %d zones\n", |
| conf->nr_strip_zones); |
| } |
| } |
| printk(KERN_INFO "raid0: FINAL %d zones\n", conf->nr_strip_zones); |
| |
| conf->strip_zone = kzalloc(sizeof(struct strip_zone)* |
| conf->nr_strip_zones, GFP_KERNEL); |
| if (!conf->strip_zone) |
| return 1; |
| conf->devlist = kzalloc(sizeof(mdk_rdev_t*)* |
| conf->nr_strip_zones*mddev->raid_disks, |
| GFP_KERNEL); |
| if (!conf->devlist) |
| return 1; |
| |
| /* The first zone must contain all devices, so here we check that |
| * there is a proper alignment of slots to devices and find them all |
| */ |
| zone = &conf->strip_zone[0]; |
| cnt = 0; |
| smallest = NULL; |
| zone->dev = conf->devlist; |
| list_for_each_entry(rdev1, &mddev->disks, same_set) { |
| int j = rdev1->raid_disk; |
| |
| if (j < 0 || j >= mddev->raid_disks) { |
| printk(KERN_ERR "raid0: bad disk number %d - " |
| "aborting!\n", j); |
| goto abort; |
| } |
| if (zone->dev[j]) { |
| printk(KERN_ERR "raid0: multiple devices for %d - " |
| "aborting!\n", j); |
| goto abort; |
| } |
| zone->dev[j] = rdev1; |
| |
| blk_queue_stack_limits(mddev->queue, |
| rdev1->bdev->bd_disk->queue); |
| /* as we don't honour merge_bvec_fn, we must never risk |
| * violating it, so limit ->max_sector to one PAGE, as |
| * a one page request is never in violation. |
| */ |
| |
| if (rdev1->bdev->bd_disk->queue->merge_bvec_fn && |
| mddev->queue->max_sectors > (PAGE_SIZE>>9)) |
| blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); |
| |
| if (!smallest || (rdev1->sectors < smallest->sectors)) |
| smallest = rdev1; |
| cnt++; |
| } |
| if (cnt != mddev->raid_disks) { |
| printk(KERN_ERR "raid0: too few disks (%d of %d) - " |
| "aborting!\n", cnt, mddev->raid_disks); |
| goto abort; |
| } |
| zone->nb_dev = cnt; |
| zone->sectors = smallest->sectors * cnt; |
| zone->zone_start = 0; |
| |
| current_start = smallest->sectors; |
| curr_zone_start = zone->sectors; |
| |
| /* now do the other zones */ |
| for (i = 1; i < conf->nr_strip_zones; i++) |
| { |
| zone = conf->strip_zone + i; |
| zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks; |
| |
| printk(KERN_INFO "raid0: zone %d\n", i); |
| zone->dev_start = current_start; |
| smallest = NULL; |
| c = 0; |
| |
| for (j=0; j<cnt; j++) { |
| char b[BDEVNAME_SIZE]; |
| rdev = conf->strip_zone[0].dev[j]; |
| printk(KERN_INFO "raid0: checking %s ...", |
| bdevname(rdev->bdev, b)); |
| if (rdev->sectors <= current_start) { |
| printk(KERN_INFO " nope.\n"); |
| continue; |
| } |
| printk(KERN_INFO " contained as device %d\n", c); |
| zone->dev[c] = rdev; |
| c++; |
| if (!smallest || rdev->sectors < smallest->sectors) { |
| smallest = rdev; |
| printk(KERN_INFO " (%llu) is smallest!.\n", |
| (unsigned long long)rdev->sectors); |
| } |
| } |
| |
| zone->nb_dev = c; |
| zone->sectors = (smallest->sectors - current_start) * c; |
| printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n", |
| zone->nb_dev, (unsigned long long)zone->sectors); |
| |
| zone->zone_start = curr_zone_start; |
| curr_zone_start += zone->sectors; |
| |
| current_start = smallest->sectors; |
| printk(KERN_INFO "raid0: current zone start: %llu\n", |
| (unsigned long long)current_start); |
| } |
| |
| /* Now find appropriate hash spacing. |
| * We want a number which causes most hash entries to cover |
| * at most two strips, but the hash table must be at most |
| * 1 PAGE. We choose the smallest strip, or contiguous collection |
| * of strips, that has big enough size. We never consider the last |
| * strip though as it's size has no bearing on the efficacy of the hash |
| * table. |
| */ |
| conf->spacing = curr_zone_start; |
| min_spacing = curr_zone_start; |
| sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*)); |
| for (i=0; i < conf->nr_strip_zones-1; i++) { |
| sector_t s = 0; |
| for (j = i; j < conf->nr_strip_zones - 1 && |
| s < min_spacing; j++) |
| s += conf->strip_zone[j].sectors; |
| if (s >= min_spacing && s < conf->spacing) |
| conf->spacing = s; |
| } |
| |
| mddev->queue->unplug_fn = raid0_unplug; |
| |
| mddev->queue->backing_dev_info.congested_fn = raid0_congested; |
| mddev->queue->backing_dev_info.congested_data = mddev; |
| |
| printk(KERN_INFO "raid0: done.\n"); |
| return 0; |
| abort: |
| return 1; |
| } |
| |
| /** |
| * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged |
| * @q: request queue |
| * @bvm: properties of new bio |
| * @biovec: the request that could be merged to it. |
| * |
| * Return amount of bytes we can accept at this offset |
| */ |
| static int raid0_mergeable_bvec(struct request_queue *q, |
| struct bvec_merge_data *bvm, |
| struct bio_vec *biovec) |
| { |
| mddev_t *mddev = q->queuedata; |
| sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); |
| int max; |
| unsigned int chunk_sectors = mddev->chunk_size >> 9; |
| unsigned int bio_sectors = bvm->bi_size >> 9; |
| |
| max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; |
| if (max < 0) max = 0; /* bio_add cannot handle a negative return */ |
| if (max <= biovec->bv_len && bio_sectors == 0) |
| return biovec->bv_len; |
| else |
| return max; |
| } |
| |
| static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks) |
| { |
| sector_t array_sectors = 0; |
| mdk_rdev_t *rdev; |
| |
| WARN_ONCE(sectors || raid_disks, |
| "%s does not support generic reshape\n", __func__); |
| |
| list_for_each_entry(rdev, &mddev->disks, same_set) |
| array_sectors += rdev->sectors; |
| |
| return array_sectors; |
| } |
| |
| static int raid0_run (mddev_t *mddev) |
| { |
| unsigned cur=0, i=0, nb_zone; |
| s64 sectors; |
| raid0_conf_t *conf; |
| |
| if (mddev->chunk_size == 0) { |
| printk(KERN_ERR "md/raid0: non-zero chunk size required.\n"); |
| return -EINVAL; |
| } |
| printk(KERN_INFO "%s: setting max_sectors to %d, segment boundary to %d\n", |
| mdname(mddev), |
| mddev->chunk_size >> 9, |
| (mddev->chunk_size>>1)-1); |
| blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9); |
| blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1); |
| mddev->queue->queue_lock = &mddev->queue->__queue_lock; |
| |
| conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL); |
| if (!conf) |
| goto out; |
| mddev->private = (void *)conf; |
| |
| conf->strip_zone = NULL; |
| conf->devlist = NULL; |
| if (create_strip_zones (mddev)) |
| goto out_free_conf; |
| |
| /* calculate array device size */ |
| mddev->array_sectors = raid0_size(mddev, 0, 0); |
| |
| printk(KERN_INFO "raid0 : md_size is %llu sectors.\n", |
| (unsigned long long)mddev->array_sectors); |
| printk(KERN_INFO "raid0 : conf->spacing is %llu sectors.\n", |
| (unsigned long long)conf->spacing); |
| { |
| sector_t s = mddev->array_sectors; |
| sector_t space = conf->spacing; |
| int round; |
| conf->sector_shift = 0; |
| if (sizeof(sector_t) > sizeof(u32)) { |
| /*shift down space and s so that sector_div will work */ |
| while (space > (sector_t) (~(u32)0)) { |
| s >>= 1; |
| space >>= 1; |
| s += 1; /* force round-up */ |
| conf->sector_shift++; |
| } |
| } |
| round = sector_div(s, (u32)space) ? 1 : 0; |
| nb_zone = s + round; |
| } |
| printk(KERN_INFO "raid0 : nb_zone is %d.\n", nb_zone); |
| |
| printk(KERN_INFO "raid0 : Allocating %zu bytes for hash.\n", |
| nb_zone*sizeof(struct strip_zone*)); |
| conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL); |
| if (!conf->hash_table) |
| goto out_free_conf; |
| sectors = conf->strip_zone[cur].sectors; |
| |
| conf->hash_table[0] = conf->strip_zone + cur; |
| for (i=1; i< nb_zone; i++) { |
| while (sectors <= conf->spacing) { |
| cur++; |
| sectors += conf->strip_zone[cur].sectors; |
| } |
| sectors -= conf->spacing; |
| conf->hash_table[i] = conf->strip_zone + cur; |
| } |
| if (conf->sector_shift) { |
| conf->spacing >>= conf->sector_shift; |
| /* round spacing up so when we divide by it, we |
| * err on the side of too-low, which is safest |
| */ |
| conf->spacing++; |
| } |
| |
| /* calculate the max read-ahead size. |
| * For read-ahead of large files to be effective, we need to |
| * readahead at least twice a whole stripe. i.e. number of devices |
| * multiplied by chunk size times 2. |
| * If an individual device has an ra_pages greater than the |
| * chunk size, then we will not drive that device as hard as it |
| * wants. We consider this a configuration error: a larger |
| * chunksize should be used in that case. |
| */ |
| { |
| int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_SIZE; |
| if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) |
| mddev->queue->backing_dev_info.ra_pages = 2* stripe; |
| } |
| |
| |
| blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec); |
| return 0; |
| |
| out_free_conf: |
| kfree(conf->strip_zone); |
| kfree(conf->devlist); |
| kfree(conf); |
| mddev->private = NULL; |
| out: |
| return -ENOMEM; |
| } |
| |
| static int raid0_stop (mddev_t *mddev) |
| { |
| raid0_conf_t *conf = mddev_to_conf(mddev); |
| |
| blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
| kfree(conf->hash_table); |
| conf->hash_table = NULL; |
| kfree(conf->strip_zone); |
| conf->strip_zone = NULL; |
| kfree(conf); |
| mddev->private = NULL; |
| |
| return 0; |
| } |
| |
| static int raid0_make_request (struct request_queue *q, struct bio *bio) |
| { |
| mddev_t *mddev = q->queuedata; |
| unsigned int sect_in_chunk, chunksect_bits, chunk_sects; |
| raid0_conf_t *conf = mddev_to_conf(mddev); |
| struct strip_zone *zone; |
| mdk_rdev_t *tmp_dev; |
| sector_t chunk; |
| sector_t sector, rsect; |
| const int rw = bio_data_dir(bio); |
| int cpu; |
| |
| if (unlikely(bio_barrier(bio))) { |
| bio_endio(bio, -EOPNOTSUPP); |
| return 0; |
| } |
| |
| cpu = part_stat_lock(); |
| part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); |
| part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], |
| bio_sectors(bio)); |
| part_stat_unlock(); |
| |
| chunk_sects = mddev->chunk_size >> 9; |
| chunksect_bits = ffz(~chunk_sects); |
| sector = bio->bi_sector; |
| |
| if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) { |
| struct bio_pair *bp; |
| /* Sanity check -- queue functions should prevent this happening */ |
| if (bio->bi_vcnt != 1 || |
| bio->bi_idx != 0) |
| goto bad_map; |
| /* This is a one page bio that upper layers |
| * refuse to split for us, so we need to split it. |
| */ |
| bp = bio_split(bio, chunk_sects - (bio->bi_sector & (chunk_sects - 1))); |
| if (raid0_make_request(q, &bp->bio1)) |
| generic_make_request(&bp->bio1); |
| if (raid0_make_request(q, &bp->bio2)) |
| generic_make_request(&bp->bio2); |
| |
| bio_pair_release(bp); |
| return 0; |
| } |
| |
| |
| { |
| sector_t x = sector >> conf->sector_shift; |
| sector_div(x, (u32)conf->spacing); |
| zone = conf->hash_table[x]; |
| } |
| |
| while (sector >= zone->zone_start + zone->sectors) |
| zone++; |
| |
| sect_in_chunk = bio->bi_sector & (chunk_sects - 1); |
| |
| |
| { |
| sector_t x = (sector - zone->zone_start) >> chunksect_bits; |
| |
| sector_div(x, zone->nb_dev); |
| chunk = x; |
| |
| x = sector >> chunksect_bits; |
| tmp_dev = zone->dev[sector_div(x, zone->nb_dev)]; |
| } |
| rsect = (chunk << chunksect_bits) + zone->dev_start + sect_in_chunk; |
| |
| bio->bi_bdev = tmp_dev->bdev; |
| bio->bi_sector = rsect + tmp_dev->data_offset; |
| |
| /* |
| * Let the main block layer submit the IO and resolve recursion: |
| */ |
| return 1; |
| |
| bad_map: |
| printk("raid0_make_request bug: can't convert block across chunks" |
| " or bigger than %dk %llu %d\n", chunk_sects / 2, |
| (unsigned long long)bio->bi_sector, bio->bi_size >> 10); |
| |
| bio_io_error(bio); |
| return 0; |
| } |
| |
| static void raid0_status (struct seq_file *seq, mddev_t *mddev) |
| { |
| #undef MD_DEBUG |
| #ifdef MD_DEBUG |
| int j, k, h; |
| char b[BDEVNAME_SIZE]; |
| raid0_conf_t *conf = mddev_to_conf(mddev); |
| |
| h = 0; |
| for (j = 0; j < conf->nr_strip_zones; j++) { |
| seq_printf(seq, " z%d", j); |
| if (conf->hash_table[h] == conf->strip_zone+j) |
| seq_printf(seq, "(h%d)", h++); |
| seq_printf(seq, "=["); |
| for (k = 0; k < conf->strip_zone[j].nb_dev; k++) |
| seq_printf(seq, "%s/", bdevname( |
| conf->strip_zone[j].dev[k]->bdev,b)); |
| |
| seq_printf(seq, "] zs=%d ds=%d s=%d\n", |
| conf->strip_zone[j].zone_start, |
| conf->strip_zone[j].dev_start, |
| conf->strip_zone[j].sectors); |
| } |
| #endif |
| seq_printf(seq, " %dk chunks", mddev->chunk_size/1024); |
| return; |
| } |
| |
| static struct mdk_personality raid0_personality= |
| { |
| .name = "raid0", |
| .level = 0, |
| .owner = THIS_MODULE, |
| .make_request = raid0_make_request, |
| .run = raid0_run, |
| .stop = raid0_stop, |
| .status = raid0_status, |
| .size = raid0_size, |
| }; |
| |
| static int __init raid0_init (void) |
| { |
| return register_md_personality (&raid0_personality); |
| } |
| |
| static void raid0_exit (void) |
| { |
| unregister_md_personality (&raid0_personality); |
| } |
| |
| module_init(raid0_init); |
| module_exit(raid0_exit); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("md-personality-2"); /* RAID0 */ |
| MODULE_ALIAS("md-raid0"); |
| MODULE_ALIAS("md-level-0"); |