diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/md/raid0.c | 838 |
1 files changed, 838 insertions, 0 deletions
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c new file mode 100644 index 000000000..ee2cfd6c2 --- /dev/null +++ b/drivers/md/raid0.c @@ -0,0 +1,838 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + 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. + +*/ + +#include <linux/blkdev.h> +#include <linux/seq_file.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <trace/events/block.h> +#include "md.h" +#include "raid0.h" +#include "raid5.h" + +static int default_layout = 0; +module_param(default_layout, int, 0644); + +#define UNSUPPORTED_MDDEV_FLAGS \ + ((1L << MD_HAS_JOURNAL) | \ + (1L << MD_JOURNAL_CLEAN) | \ + (1L << MD_FAILFAST_SUPPORTED) |\ + (1L << MD_HAS_PPL) | \ + (1L << MD_HAS_MULTIPLE_PPLS)) + +/* + * 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; + pr_debug("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++) { + char line[200]; + int len = 0; + + for (k = 0; k < conf->strip_zone[j].nb_dev; k++) + len += scnprintf(line+len, 200-len, "%s%s", k?"/":"", + bdevname(conf->devlist[j*raid_disks + + k]->bdev, b)); + pr_debug("md: zone%d=[%s]\n", j, line); + + zone_size = conf->strip_zone[j].zone_end - zone_start; + pr_debug(" 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; + } +} + +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); + unsigned blksize = 512; + + *private_conf = ERR_PTR(-ENOMEM); + 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; + + blksize = max(blksize, queue_logical_block_size( + rdev1->bdev->bd_disk->queue)); + + 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); + + /* + * 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) % blksize) { + pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n", + mdname(mddev), + mddev->chunk_sectors << 9, blksize); + err = -EINVAL; + goto abort; + } + + err = -ENOMEM; + conf->strip_zone = kcalloc(conf->nr_strip_zones, + sizeof(struct strip_zone), + GFP_KERNEL); + if (!conf->strip_zone) + goto abort; + conf->devlist = kzalloc(array3_size(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) { + pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n", + mdname(mddev)); + goto abort; + } + if (j >= mddev->raid_disks) { + pr_warn("md/raid0:%s: bad disk number %d - aborting!\n", + mdname(mddev), j); + goto abort; + } + if (dev[j]) { + pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n", + mdname(mddev), j); + goto abort; + } + dev[j] = rdev1; + + if (!smallest || (rdev1->sectors < smallest->sectors)) + smallest = rdev1; + cnt++; + } + if (cnt != mddev->raid_disks) { + pr_warn("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); + } + + if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) { + conf->layout = RAID0_ORIG_LAYOUT; + } else if (mddev->layout == RAID0_ORIG_LAYOUT || + mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) { + conf->layout = mddev->layout; + } else if (default_layout == RAID0_ORIG_LAYOUT || + default_layout == RAID0_ALT_MULTIZONE_LAYOUT) { + conf->layout = default_layout; + } else { + pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n", + mdname(mddev)); + pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n"); + err = -EOPNOTSUPP; + goto abort; + } + + if (conf->layout == RAID0_ORIG_LAYOUT) { + for (i = 1; i < conf->nr_strip_zones; i++) { + sector_t first_sector = conf->strip_zone[i-1].zone_end; + + sector_div(first_sector, mddev->chunk_sectors); + zone = conf->strip_zone + i; + /* disk_shift is first disk index used in the zone */ + zone->disk_shift = sector_div(first_sector, + zone->nb_dev); + } + } + + 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 = ERR_PTR(err); + 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 performance +*/ +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)]; +} + +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 & + ~(sector_t)(mddev->chunk_sectors-1)); + + return array_sectors; +} + +static void raid0_free(struct mddev *mddev, void *priv); + +static int raid0_run(struct mddev *mddev) +{ + struct r0conf *conf; + int ret; + + if (mddev->chunk_sectors == 0) { + pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev)); + return -EINVAL; + } + if (md_check_no_bitmap(mddev)) + return -EINVAL; + + /* 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; + if (mddev->queue) { + struct md_rdev *rdev; + bool discard_supported = false; + + blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); + blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); + blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors); + blk_queue_max_discard_sectors(mddev->queue, UINT_MAX); + + blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); + blk_queue_io_opt(mddev->queue, + (mddev->chunk_sectors << 9) * mddev->raid_disks); + + rdev_for_each(rdev, mddev) { + disk_stack_limits(mddev->gendisk, rdev->bdev, + rdev->data_offset << 9); + if (blk_queue_discard(bdev_get_queue(rdev->bdev))) + discard_supported = true; + } + if (!discard_supported) + blk_queue_flag_clear(QUEUE_FLAG_DISCARD, mddev->queue); + else + blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue); + } + + /* calculate array device size */ + md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); + + pr_debug("md/raid0:%s: md_size is %llu sectors.\n", + mdname(mddev), + (unsigned long long)mddev->array_sectors); + + dump_zones(mddev); + + ret = md_integrity_register(mddev); + + return ret; +} + +static void raid0_free(struct mddev *mddev, void *priv) +{ + struct r0conf *conf = priv; + + kfree(conf->strip_zone); + kfree(conf->devlist); + kfree(conf); +} + +/* + * Convert disk_index to the disk order in which it is read/written. + * For example, if we have 4 disks, they are numbered 0,1,2,3. If we + * write the disks starting at disk 3, then the read/write order would + * be disk 3, then 0, then 1, and then disk 2 and we want map_disk_shift() + * to map the disks as follows 0,1,2,3 => 1,2,3,0. So disk 0 would map + * to 1, 1 to 2, 2 to 3, and 3 to 0. That way we can compare disks in + * that 'output' space to understand the read/write disk ordering. + */ +static int map_disk_shift(int disk_index, int num_disks, int disk_shift) +{ + return ((disk_index + num_disks - disk_shift) % num_disks); +} + +static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) +{ + struct r0conf *conf = mddev->private; + struct strip_zone *zone; + sector_t start = bio->bi_iter.bi_sector; + sector_t end; + unsigned int stripe_size; + sector_t first_stripe_index, last_stripe_index; + sector_t start_disk_offset; + unsigned int start_disk_index; + sector_t end_disk_offset; + unsigned int end_disk_index; + unsigned int disk; + sector_t orig_start, orig_end; + + orig_start = start; + zone = find_zone(conf, &start); + + if (bio_end_sector(bio) > zone->zone_end) { + struct bio *split = bio_split(bio, + zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO, + &mddev->bio_set); + bio_chain(split, bio); + submit_bio_noacct(bio); + bio = split; + end = zone->zone_end; + } else + end = bio_end_sector(bio); + + orig_end = end; + if (zone != conf->strip_zone) + end = end - zone[-1].zone_end; + + /* Now start and end is the offset in zone */ + stripe_size = zone->nb_dev * mddev->chunk_sectors; + + first_stripe_index = start; + sector_div(first_stripe_index, stripe_size); + last_stripe_index = end; + sector_div(last_stripe_index, stripe_size); + + /* In the first zone the original and alternate layouts are the same */ + if ((conf->layout == RAID0_ORIG_LAYOUT) && (zone != conf->strip_zone)) { + sector_div(orig_start, mddev->chunk_sectors); + start_disk_index = sector_div(orig_start, zone->nb_dev); + start_disk_index = map_disk_shift(start_disk_index, + zone->nb_dev, + zone->disk_shift); + sector_div(orig_end, mddev->chunk_sectors); + end_disk_index = sector_div(orig_end, zone->nb_dev); + end_disk_index = map_disk_shift(end_disk_index, + zone->nb_dev, zone->disk_shift); + } else { + start_disk_index = (int)(start - first_stripe_index * stripe_size) / + mddev->chunk_sectors; + end_disk_index = (int)(end - last_stripe_index * stripe_size) / + mddev->chunk_sectors; + } + start_disk_offset = ((int)(start - first_stripe_index * stripe_size) % + mddev->chunk_sectors) + + first_stripe_index * mddev->chunk_sectors; + end_disk_offset = ((int)(end - last_stripe_index * stripe_size) % + mddev->chunk_sectors) + + last_stripe_index * mddev->chunk_sectors; + + for (disk = 0; disk < zone->nb_dev; disk++) { + sector_t dev_start, dev_end; + struct bio *discard_bio = NULL; + struct md_rdev *rdev; + int compare_disk; + + compare_disk = map_disk_shift(disk, zone->nb_dev, + zone->disk_shift); + + if (compare_disk < start_disk_index) + dev_start = (first_stripe_index + 1) * + mddev->chunk_sectors; + else if (compare_disk > start_disk_index) + dev_start = first_stripe_index * mddev->chunk_sectors; + else + dev_start = start_disk_offset; + + if (compare_disk < end_disk_index) + dev_end = (last_stripe_index + 1) * mddev->chunk_sectors; + else if (compare_disk > end_disk_index) + dev_end = last_stripe_index * mddev->chunk_sectors; + else + dev_end = end_disk_offset; + + if (dev_end <= dev_start) + continue; + + rdev = conf->devlist[(zone - conf->strip_zone) * + conf->strip_zone[0].nb_dev + disk]; + if (__blkdev_issue_discard(rdev->bdev, + dev_start + zone->dev_start + rdev->data_offset, + dev_end - dev_start, GFP_NOIO, 0, &discard_bio) || + !discard_bio) + continue; + bio_chain(discard_bio, bio); + bio_clone_blkg_association(discard_bio, bio); + if (mddev->gendisk) + trace_block_bio_remap(bdev_get_queue(rdev->bdev), + discard_bio, disk_devt(mddev->gendisk), + bio->bi_iter.bi_sector); + submit_bio_noacct(discard_bio); + } + bio_endio(bio); +} + +static bool raid0_make_request(struct mddev *mddev, struct bio *bio) +{ + struct r0conf *conf = mddev->private; + struct strip_zone *zone; + struct md_rdev *tmp_dev; + sector_t bio_sector; + sector_t sector; + sector_t orig_sector; + unsigned chunk_sects; + unsigned sectors; + + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) + return true; + + if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) { + raid0_handle_discard(mddev, bio); + return true; + } + + bio_sector = bio->bi_iter.bi_sector; + sector = bio_sector; + chunk_sects = mddev->chunk_sectors; + + sectors = chunk_sects - + (likely(is_power_of_2(chunk_sects)) + ? (sector & (chunk_sects-1)) + : sector_div(sector, chunk_sects)); + + /* Restore due to sector_div */ + sector = bio_sector; + + if (sectors < bio_sectors(bio)) { + struct bio *split = bio_split(bio, sectors, GFP_NOIO, + &mddev->bio_set); + bio_chain(split, bio); + submit_bio_noacct(bio); + bio = split; + } + + orig_sector = sector; + zone = find_zone(mddev->private, §or); + switch (conf->layout) { + case RAID0_ORIG_LAYOUT: + tmp_dev = map_sector(mddev, zone, orig_sector, §or); + break; + case RAID0_ALT_MULTIZONE_LAYOUT: + tmp_dev = map_sector(mddev, zone, sector, §or); + break; + default: + WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev)); + bio_io_error(bio); + return true; + } + + if (unlikely(is_mddev_broken(tmp_dev, "raid0"))) { + bio_io_error(bio); + return true; + } + + bio_set_dev(bio, tmp_dev->bdev); + bio->bi_iter.bi_sector = sector + zone->dev_start + + tmp_dev->data_offset; + + if (mddev->gendisk) + trace_block_bio_remap(bio->bi_disk->queue, bio, + disk_devt(mddev->gendisk), bio_sector); + mddev_check_writesame(mddev, bio); + mddev_check_write_zeroes(mddev, bio); + submit_bio_noacct(bio); + return true; +} + +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) { + pr_warn("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) { + pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + rdev->sectors = mddev->dev_sectors; + } + + /* 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; + mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); + + 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)) { + pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n", + mdname(mddev), + mddev->layout); + return ERR_PTR(-EINVAL); + } + if (mddev->raid_disks & 1) { + pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + if (mddev->degraded != (mddev->raid_disks>>1)) { + pr_warn("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; + mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); + + 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) { + pr_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; + mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); + + 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->bitmap) { + pr_warn("md/raid0: %s: cannot takeover array with bitmap\n", + mdname(mddev)); + return ERR_PTR(-EBUSY); + } + if (mddev->level == 4) + return raid0_takeover_raid45(mddev); + + if (mddev->level == 5) { + if (mddev->layout == ALGORITHM_PARITY_N) + return raid0_takeover_raid45(mddev); + + pr_warn("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); + + pr_warn("Takeover from raid%i to raid0 not supported\n", + mddev->level); + + return ERR_PTR(-EINVAL); +} + +static void raid0_quiesce(struct mddev *mddev, int quiesce) +{ +} + +static struct md_personality raid0_personality= +{ + .name = "raid0", + .level = 0, + .owner = THIS_MODULE, + .make_request = raid0_make_request, + .run = raid0_run, + .free = raid0_free, + .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"); |