/* 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/module.h> #include <linux/raid/raid0.h> #define MAJOR_NR MD_MAJOR #define MD_DRIVER #define MD_PERSONALITY 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_offset, curr_zone_offset; sector_t min_spacing; raid0_conf_t *conf = mddev_to_conf(mddev); mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev; struct list_head *tmp1, *tmp2; struct strip_zone *zone; int cnt; char b[BDEVNAME_SIZE]; /* * The number of 'same size groups' */ conf->nr_strip_zones = 0; rdev_for_each(rdev1, tmp1, mddev) { printk("raid0: looking at %s\n", bdevname(rdev1->bdev,b)); c = 0; rdev_for_each(rdev2, tmp2, mddev) { printk("raid0: comparing %s(%llu)", bdevname(rdev1->bdev,b), (unsigned long long)rdev1->size); printk(" with %s(%llu)\n", bdevname(rdev2->bdev,b), (unsigned long long)rdev2->size); if (rdev2 == rdev1) { printk("raid0: END\n"); break; } if (rdev2->size == rdev1->size) { /* * Not unique, don't count it as a new * group */ printk("raid0: EQUAL\n"); c = 1; break; } printk("raid0: NOT EQUAL\n"); } if (!c) { printk("raid0: ==> UNIQUE\n"); conf->nr_strip_zones++; printk("raid0: %d zones\n", conf->nr_strip_zones); } } printk("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; rdev_for_each(rdev1, tmp1, mddev) { int j = rdev1->raid_disk; if (j < 0 || j >= mddev->raid_disks) { printk("raid0: bad disk number %d - aborting!\n", j); goto abort; } if (zone->dev[j]) { printk("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->size <smallest->size)) smallest = rdev1; cnt++; } if (cnt != mddev->raid_disks) { printk("raid0: too few disks (%d of %d) - aborting!\n", cnt, mddev->raid_disks); goto abort; } zone->nb_dev = cnt; zone->size = smallest->size * cnt; zone->zone_offset = 0; current_offset = smallest->size; curr_zone_offset = zone->size; /* 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("raid0: zone %d\n", i); zone->dev_offset = current_offset; smallest = NULL; c = 0; for (j=0; j<cnt; j++) { char b[BDEVNAME_SIZE]; rdev = conf->strip_zone[0].dev[j]; printk("raid0: checking %s ...", bdevname(rdev->bdev,b)); if (rdev->size > current_offset) { printk(" contained as device %d\n", c); zone->dev[c] = rdev; c++; if (!smallest || (rdev->size <smallest->size)) { smallest = rdev; printk(" (%llu) is smallest!.\n", (unsigned long long)rdev->size); } } else printk(" nope.\n"); } zone->nb_dev = c; zone->size = (smallest->size - current_offset) * c; printk("raid0: zone->nb_dev: %d, size: %llu\n", zone->nb_dev, (unsigned long long)zone->size); zone->zone_offset = curr_zone_offset; curr_zone_offset += zone->size; current_offset = smallest->size; printk("raid0: current zone offset: %llu\n", (unsigned long long)current_offset); } /* 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->hash_spacing = curr_zone_offset; min_spacing = curr_zone_offset; sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*)); for (i=0; i < conf->nr_strip_zones-1; i++) { sector_t sz = 0; for (j=i; j<conf->nr_strip_zones-1 && sz < min_spacing ; j++) sz += conf->strip_zone[j].size; if (sz >= min_spacing && sz < conf->hash_spacing) conf->hash_spacing = sz; } mddev->queue->unplug_fn = raid0_unplug; mddev->queue->backing_dev_info.congested_fn = raid0_congested; mddev->queue->backing_dev_info.congested_data = mddev; printk("raid0: done.\n"); return 0; abort: return 1; } /** * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged * @q: request queue * @bio: the buffer head that's been built up so far * @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 bio *bio, struct bio_vec *biovec) { mddev_t *mddev = q->queuedata; sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); int max; unsigned int chunk_sectors = mddev->chunk_size >> 9; unsigned int bio_sectors = bio->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 int raid0_run (mddev_t *mddev) { unsigned cur=0, i=0, nb_zone; s64 size; raid0_conf_t *conf; mdk_rdev_t *rdev; struct list_head *tmp; 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); 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_size = 0; rdev_for_each(rdev, tmp, mddev) mddev->array_size += rdev->size; printk("raid0 : md_size is %llu blocks.\n", (unsigned long long)mddev->array_size); printk("raid0 : conf->hash_spacing is %llu blocks.\n", (unsigned long long)conf->hash_spacing); { sector_t s = mddev->array_size; sector_t space = conf->hash_spacing; int round; conf->preshift = 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->preshift++; } } round = sector_div(s, (u32)space) ? 1 : 0; nb_zone = s + round; } printk("raid0 : nb_zone is %d.\n", nb_zone); printk("raid0 : Allocating %Zd 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; size = conf->strip_zone[cur].size; conf->hash_table[0] = conf->strip_zone + cur; for (i=1; i< nb_zone; i++) { while (size <= conf->hash_spacing) { cur++; size += conf->strip_zone[cur].size; } size -= conf->hash_spacing; conf->hash_table[i] = conf->strip_zone + cur; } if (conf->preshift) { conf->hash_spacing >>= conf->preshift; /* round hash_spacing up so when we divide by it, we * err on the side of too-low, which is safest */ conf->hash_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, chunksize_bits, chunk_size, chunk_sects; raid0_conf_t *conf = mddev_to_conf(mddev); struct strip_zone *zone; mdk_rdev_t *tmp_dev; sector_t chunk; sector_t block, rsect; const int rw = bio_data_dir(bio); if (unlikely(bio_barrier(bio))) { bio_endio(bio, -EOPNOTSUPP); return 0; } disk_stat_inc(mddev->gendisk, ios[rw]); disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); chunk_size = mddev->chunk_size >> 10; chunk_sects = mddev->chunk_size >> 9; chunksize_bits = ffz(~chunk_size); block = bio->bi_sector >> 1; 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, bio_split_pool, 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 = block >> conf->preshift; sector_div(x, (u32)conf->hash_spacing); zone = conf->hash_table[x]; } while (block >= (zone->zone_offset + zone->size)) zone++; sect_in_chunk = bio->bi_sector & ((chunk_size<<1) -1); { sector_t x = (block - zone->zone_offset) >> chunksize_bits; sector_div(x, zone->nb_dev); chunk = x; x = block >> chunksize_bits; tmp_dev = zone->dev[sector_div(x, zone->nb_dev)]; } rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1) + 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_size, (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, "] zo=%d do=%d s=%d\n", conf->strip_zone[j].zone_offset, conf->strip_zone[j].dev_offset, conf->strip_zone[j].size); } #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, }; 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");