diff options
Diffstat (limited to 'drivers/md/raid0.c')
| -rw-r--r-- | drivers/md/raid0.c | 739 |
1 files changed, 739 insertions, 0 deletions
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c new file mode 100644 index 00000000..de63a1fc --- /dev/null +++ b/drivers/md/raid0.c @@ -0,0 +1,739 @@ +/* + 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 <linux/module.h> +#include <linux/slab.h> +#include "md.h" +#include "raid0.h" +#include "raid5.h" + +static int raid0_congested(void *data, int bits) +{ + struct mddev *mddev = data; + struct r0conf *conf = mddev->private; + struct md_rdev **devlist = conf->devlist; + int raid_disks = conf->strip_zone[0].nb_dev; + int i, ret = 0; + + if (mddev_congested(mddev, bits)) + return 1; + + for (i = 0; i < raid_disks && !ret ; i++) { + struct request_queue *q = bdev_get_queue(devlist[i]->bdev); + + ret |= bdi_congested(&q->backing_dev_info, bits); + } + return ret; +} + +/* + * inform the user of the raid configuration +*/ +static void dump_zones(struct mddev *mddev) +{ + int j, k; + sector_t zone_size = 0; + sector_t zone_start = 0; + char b[BDEVNAME_SIZE]; + struct r0conf *conf = mddev->private; + int raid_disks = conf->strip_zone[0].nb_dev; + printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n", + mdname(mddev), + conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s"); + for (j = 0; j < conf->nr_strip_zones; j++) { + printk(KERN_INFO "md: zone%d=[", j); + for (k = 0; k < conf->strip_zone[j].nb_dev; k++) + printk(KERN_CONT "%s%s", k?"/":"", + bdevname(conf->devlist[j*raid_disks + + k]->bdev, b)); + printk(KERN_CONT "]\n"); + + zone_size = conf->strip_zone[j].zone_end - zone_start; + printk(KERN_INFO " zone-offset=%10lluKB, " + "device-offset=%10lluKB, size=%10lluKB\n", + (unsigned long long)zone_start>>1, + (unsigned long long)conf->strip_zone[j].dev_start>>1, + (unsigned long long)zone_size>>1); + zone_start = conf->strip_zone[j].zone_end; + } + printk(KERN_INFO "\n"); +} + +static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) +{ + int i, c, err; + sector_t curr_zone_end, sectors; + struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev; + struct strip_zone *zone; + int cnt; + char b[BDEVNAME_SIZE]; + char b2[BDEVNAME_SIZE]; + struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL); + + if (!conf) + return -ENOMEM; + rdev_for_each(rdev1, mddev) { + pr_debug("md/raid0:%s: looking at %s\n", + mdname(mddev), + bdevname(rdev1->bdev, b)); + c = 0; + + /* round size to chunk_size */ + sectors = rdev1->sectors; + sector_div(sectors, mddev->chunk_sectors); + rdev1->sectors = sectors * mddev->chunk_sectors; + + rdev_for_each(rdev2, mddev) { + pr_debug("md/raid0:%s: comparing %s(%llu)" + " with %s(%llu)\n", + mdname(mddev), + bdevname(rdev1->bdev,b), + (unsigned long long)rdev1->sectors, + bdevname(rdev2->bdev,b2), + (unsigned long long)rdev2->sectors); + if (rdev2 == rdev1) { + pr_debug("md/raid0:%s: END\n", + mdname(mddev)); + break; + } + if (rdev2->sectors == rdev1->sectors) { + /* + * Not unique, don't count it as a new + * group + */ + pr_debug("md/raid0:%s: EQUAL\n", + mdname(mddev)); + c = 1; + break; + } + pr_debug("md/raid0:%s: NOT EQUAL\n", + mdname(mddev)); + } + if (!c) { + pr_debug("md/raid0:%s: ==> UNIQUE\n", + mdname(mddev)); + conf->nr_strip_zones++; + pr_debug("md/raid0:%s: %d zones\n", + mdname(mddev), conf->nr_strip_zones); + } + } + pr_debug("md/raid0:%s: FINAL %d zones\n", + mdname(mddev), conf->nr_strip_zones); + err = -ENOMEM; + conf->strip_zone = kzalloc(sizeof(struct strip_zone)* + conf->nr_strip_zones, GFP_KERNEL); + if (!conf->strip_zone) + goto abort; + conf->devlist = kzalloc(sizeof(struct md_rdev*)* + conf->nr_strip_zones*mddev->raid_disks, + GFP_KERNEL); + if (!conf->devlist) + goto abort; + + /* 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; + dev = conf->devlist; + err = -EINVAL; + rdev_for_each(rdev1, mddev) { + int j = rdev1->raid_disk; + + if (mddev->level == 10) { + /* taking over a raid10-n2 array */ + j /= 2; + rdev1->new_raid_disk = j; + } + + if (mddev->level == 1) { + /* taiking over a raid1 array- + * we have only one active disk + */ + j = 0; + rdev1->new_raid_disk = j; + } + + if (j < 0 || j >= mddev->raid_disks) { + printk(KERN_ERR "md/raid0:%s: bad disk number %d - " + "aborting!\n", mdname(mddev), j); + goto abort; + } + if (dev[j]) { + printk(KERN_ERR "md/raid0:%s: multiple devices for %d - " + "aborting!\n", mdname(mddev), j); + goto abort; + } + dev[j] = rdev1; + + disk_stack_limits(mddev->gendisk, rdev1->bdev, + rdev1->data_offset << 9); + + if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) + conf->has_merge_bvec = 1; + + if (!smallest || (rdev1->sectors < smallest->sectors)) + smallest = rdev1; + cnt++; + } + if (cnt != mddev->raid_disks) { + printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - " + "aborting!\n", mdname(mddev), cnt, mddev->raid_disks); + goto abort; + } + zone->nb_dev = cnt; + zone->zone_end = smallest->sectors * cnt; + + curr_zone_end = zone->zone_end; + + /* now do the other zones */ + for (i = 1; i < conf->nr_strip_zones; i++) + { + int j; + + zone = conf->strip_zone + i; + dev = conf->devlist + i * mddev->raid_disks; + + pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); + zone->dev_start = smallest->sectors; + smallest = NULL; + c = 0; + + for (j=0; j<cnt; j++) { + rdev = conf->devlist[j]; + if (rdev->sectors <= zone->dev_start) { + pr_debug("md/raid0:%s: checking %s ... nope\n", + mdname(mddev), + bdevname(rdev->bdev, b)); + continue; + } + pr_debug("md/raid0:%s: checking %s ..." + " contained as device %d\n", + mdname(mddev), + bdevname(rdev->bdev, b), c); + dev[c] = rdev; + c++; + if (!smallest || rdev->sectors < smallest->sectors) { + smallest = rdev; + pr_debug("md/raid0:%s: (%llu) is smallest!.\n", + mdname(mddev), + (unsigned long long)rdev->sectors); + } + } + + zone->nb_dev = c; + sectors = (smallest->sectors - zone->dev_start) * c; + pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", + mdname(mddev), + zone->nb_dev, (unsigned long long)sectors); + + curr_zone_end += sectors; + zone->zone_end = curr_zone_end; + + pr_debug("md/raid0:%s: current zone start: %llu\n", + mdname(mddev), + (unsigned long long)smallest->sectors); + } + mddev->queue->backing_dev_info.congested_fn = raid0_congested; + mddev->queue->backing_dev_info.congested_data = mddev; + + /* + * now since we have the hard sector sizes, we can make sure + * chunk size is a multiple of that sector size + */ + if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) { + printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n", + mdname(mddev), + mddev->chunk_sectors << 9); + goto abort; + } + + blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); + blk_queue_io_opt(mddev->queue, + (mddev->chunk_sectors << 9) * mddev->raid_disks); + + pr_debug("md/raid0:%s: done.\n", mdname(mddev)); + *private_conf = conf; + + return 0; +abort: + kfree(conf->strip_zone); + kfree(conf->devlist); + kfree(conf); + *private_conf = NULL; + return err; +} + +/* Find the zone which holds a particular offset + * Update *sectorp to be an offset in that zone + */ +static struct strip_zone *find_zone(struct r0conf *conf, + sector_t *sectorp) +{ + int i; + struct strip_zone *z = conf->strip_zone; + sector_t sector = *sectorp; + + for (i = 0; i < conf->nr_strip_zones; i++) + if (sector < z[i].zone_end) { + if (i) + *sectorp = sector - z[i-1].zone_end; + return z + i; + } + BUG(); +} + +/* + * remaps the bio to the target device. we separate two flows. + * power 2 flow and a general flow for the sake of perfromance +*/ +static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, + sector_t sector, sector_t *sector_offset) +{ + unsigned int sect_in_chunk; + sector_t chunk; + struct r0conf *conf = mddev->private; + int raid_disks = conf->strip_zone[0].nb_dev; + unsigned int chunk_sects = mddev->chunk_sectors; + + if (is_power_of_2(chunk_sects)) { + int chunksect_bits = ffz(~chunk_sects); + /* find the sector offset inside the chunk */ + sect_in_chunk = sector & (chunk_sects - 1); + sector >>= chunksect_bits; + /* chunk in zone */ + chunk = *sector_offset; + /* quotient is the chunk in real device*/ + sector_div(chunk, zone->nb_dev << chunksect_bits); + } else{ + sect_in_chunk = sector_div(sector, chunk_sects); + chunk = *sector_offset; + sector_div(chunk, chunk_sects * zone->nb_dev); + } + /* + * position the bio over the real device + * real sector = chunk in device + starting of zone + * + the position in the chunk + */ + *sector_offset = (chunk * chunk_sects) + sect_in_chunk; + return conf->devlist[(zone - conf->strip_zone)*raid_disks + + sector_div(sector, zone->nb_dev)]; +} + +/** + * raid0_mergeable_bvec -- tell bio layer if 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) +{ + struct mddev *mddev = q->queuedata; + struct r0conf *conf = mddev->private; + sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); + sector_t sector_offset = sector; + int max; + unsigned int chunk_sectors = mddev->chunk_sectors; + unsigned int bio_sectors = bvm->bi_size >> 9; + struct strip_zone *zone; + struct md_rdev *rdev; + struct request_queue *subq; + + if (is_power_of_2(chunk_sectors)) + max = (chunk_sectors - ((sector & (chunk_sectors-1)) + + bio_sectors)) << 9; + else + max = (chunk_sectors - (sector_div(sector, chunk_sectors) + + 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; + if (max < biovec->bv_len) + /* too small already, no need to check further */ + return max; + if (!conf->has_merge_bvec) + return max; + + /* May need to check subordinate device */ + sector = sector_offset; + zone = find_zone(mddev->private, §or_offset); + rdev = map_sector(mddev, zone, sector, §or_offset); + subq = bdev_get_queue(rdev->bdev); + if (subq->merge_bvec_fn) { + bvm->bi_bdev = rdev->bdev; + bvm->bi_sector = sector_offset + zone->dev_start + + rdev->data_offset; + return min(max, subq->merge_bvec_fn(subq, bvm, biovec)); + } else + return max; +} + +static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) +{ + sector_t array_sectors = 0; + struct md_rdev *rdev; + + WARN_ONCE(sectors || raid_disks, + "%s does not support generic reshape\n", __func__); + + rdev_for_each(rdev, mddev) + array_sectors += rdev->sectors; + + return array_sectors; +} + +static int raid0_stop(struct mddev *mddev); + +static int raid0_run(struct mddev *mddev) +{ + struct r0conf *conf; + int ret; + + if (mddev->chunk_sectors == 0) { + printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n", + mdname(mddev)); + return -EINVAL; + } + if (md_check_no_bitmap(mddev)) + return -EINVAL; + blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); + + /* if private is not null, we are here after takeover */ + if (mddev->private == NULL) { + ret = create_strip_zones(mddev, &conf); + if (ret < 0) + return ret; + mddev->private = conf; + } + conf = mddev->private; + + /* calculate array device size */ + md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); + + printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n", + mdname(mddev), + (unsigned long long)mddev->array_sectors); + /* 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_sectors << 9) / 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); + dump_zones(mddev); + + ret = md_integrity_register(mddev); + if (ret) + raid0_stop(mddev); + + return ret; +} + +static int raid0_stop(struct mddev *mddev) +{ + struct r0conf *conf = mddev->private; + + blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ + kfree(conf->strip_zone); + kfree(conf->devlist); + kfree(conf); + mddev->private = NULL; + return 0; +} + +/* + * Is io distribute over 1 or more chunks ? +*/ +static inline int is_io_in_chunk_boundary(struct mddev *mddev, + unsigned int chunk_sects, struct bio *bio) +{ + if (likely(is_power_of_2(chunk_sects))) { + return chunk_sects >= ((bio->bi_sector & (chunk_sects-1)) + + (bio->bi_size >> 9)); + } else{ + sector_t sector = bio->bi_sector; + return chunk_sects >= (sector_div(sector, chunk_sects) + + (bio->bi_size >> 9)); + } +} + +static void raid0_make_request(struct mddev *mddev, struct bio *bio) +{ + unsigned int chunk_sects; + sector_t sector_offset; + struct strip_zone *zone; + struct md_rdev *tmp_dev; + + if (unlikely(bio->bi_rw & REQ_FLUSH)) { + md_flush_request(mddev, bio); + return; + } + + chunk_sects = mddev->chunk_sectors; + if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) { + sector_t sector = bio->bi_sector; + 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. + */ + if (likely(is_power_of_2(chunk_sects))) + bp = bio_split(bio, chunk_sects - (sector & + (chunk_sects-1))); + else + bp = bio_split(bio, chunk_sects - + sector_div(sector, chunk_sects)); + raid0_make_request(mddev, &bp->bio1); + raid0_make_request(mddev, &bp->bio2); + bio_pair_release(bp); + return; + } + + sector_offset = bio->bi_sector; + zone = find_zone(mddev->private, §or_offset); + tmp_dev = map_sector(mddev, zone, bio->bi_sector, + §or_offset); + bio->bi_bdev = tmp_dev->bdev; + bio->bi_sector = sector_offset + zone->dev_start + + tmp_dev->data_offset; + + generic_make_request(bio); + return; + +bad_map: + printk("md/raid0:%s: make_request bug: can't convert block across chunks" + " or bigger than %dk %llu %d\n", + mdname(mddev), chunk_sects / 2, + (unsigned long long)bio->bi_sector, bio->bi_size >> 10); + + bio_io_error(bio); + return; +} + +static void raid0_status(struct seq_file *seq, struct mddev *mddev) +{ + seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); + return; +} + +static void *raid0_takeover_raid45(struct mddev *mddev) +{ + struct md_rdev *rdev; + struct r0conf *priv_conf; + + if (mddev->degraded != 1) { + printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", + mdname(mddev), + mddev->degraded); + return ERR_PTR(-EINVAL); + } + + rdev_for_each(rdev, mddev) { + /* check slot number for a disk */ + if (rdev->raid_disk == mddev->raid_disks-1) { + printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + } + + /* Set new parameters */ + mddev->new_level = 0; + mddev->new_layout = 0; + mddev->new_chunk_sectors = mddev->chunk_sectors; + mddev->raid_disks--; + mddev->delta_disks = -1; + /* make sure it will be not marked as dirty */ + mddev->recovery_cp = MaxSector; + + create_strip_zones(mddev, &priv_conf); + return priv_conf; +} + +static void *raid0_takeover_raid10(struct mddev *mddev) +{ + struct r0conf *priv_conf; + + /* Check layout: + * - far_copies must be 1 + * - near_copies must be 2 + * - disks number must be even + * - all mirrors must be already degraded + */ + if (mddev->layout != ((1 << 8) + 2)) { + printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n", + mdname(mddev), + mddev->layout); + return ERR_PTR(-EINVAL); + } + if (mddev->raid_disks & 1) { + printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + if (mddev->degraded != (mddev->raid_disks>>1)) { + printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + + /* Set new parameters */ + mddev->new_level = 0; + mddev->new_layout = 0; + mddev->new_chunk_sectors = mddev->chunk_sectors; + mddev->delta_disks = - mddev->raid_disks / 2; + mddev->raid_disks += mddev->delta_disks; + mddev->degraded = 0; + /* make sure it will be not marked as dirty */ + mddev->recovery_cp = MaxSector; + + create_strip_zones(mddev, &priv_conf); + return priv_conf; +} + +static void *raid0_takeover_raid1(struct mddev *mddev) +{ + struct r0conf *priv_conf; + int chunksect; + + /* Check layout: + * - (N - 1) mirror drives must be already faulty + */ + if ((mddev->raid_disks - 1) != mddev->degraded) { + printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + + /* + * a raid1 doesn't have the notion of chunk size, so + * figure out the largest suitable size we can use. + */ + chunksect = 64 * 2; /* 64K by default */ + + /* The array must be an exact multiple of chunksize */ + while (chunksect && (mddev->array_sectors & (chunksect - 1))) + chunksect >>= 1; + + if ((chunksect << 9) < PAGE_SIZE) + /* array size does not allow a suitable chunk size */ + return ERR_PTR(-EINVAL); + + /* Set new parameters */ + mddev->new_level = 0; + mddev->new_layout = 0; + mddev->new_chunk_sectors = chunksect; + mddev->chunk_sectors = chunksect; + mddev->delta_disks = 1 - mddev->raid_disks; + mddev->raid_disks = 1; + /* make sure it will be not marked as dirty */ + mddev->recovery_cp = MaxSector; + + create_strip_zones(mddev, &priv_conf); + return priv_conf; +} + +static void *raid0_takeover(struct mddev *mddev) +{ + /* raid0 can take over: + * raid4 - if all data disks are active. + * raid5 - providing it is Raid4 layout and one disk is faulty + * raid10 - assuming we have all necessary active disks + * raid1 - with (N -1) mirror drives faulty + */ + if (mddev->level == 4) + return raid0_takeover_raid45(mddev); + + if (mddev->level == 5) { + if (mddev->layout == ALGORITHM_PARITY_N) + return raid0_takeover_raid45(mddev); + + printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", + mdname(mddev), ALGORITHM_PARITY_N); + } + + if (mddev->level == 10) + return raid0_takeover_raid10(mddev); + + if (mddev->level == 1) + return raid0_takeover_raid1(mddev); + + printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n", + mddev->level); + + return ERR_PTR(-EINVAL); +} + +static void raid0_quiesce(struct mddev *mddev, int state) +{ +} + +static struct md_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, + .takeover = raid0_takeover, + .quiesce = raid0_quiesce, +}; + +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_DESCRIPTION("RAID0 (striping) personality for MD"); +MODULE_ALIAS("md-personality-2"); /* RAID0 */ +MODULE_ALIAS("md-raid0"); +MODULE_ALIAS("md-level-0"); |