Initial import

1 files changed, 749 insertions, 0 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
new file mode 100644
index 000000000..efb654eb5
--- /dev/null
+++ b/drivers/md/raid0.c
@@ -0,0 +1,749 @@
+/*
+   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(struct mddev *mddev, int bits)
+{
+	struct r0conf *conf = mddev->private;
+	struct md_rdev **devlist = conf->devlist;
+	int raid_disks = conf->strip_zone[0].nb_dev;
+	int i, ret = 0;
+
+	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);
+	bool discard_supported = false;
+
+	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) {
+			printk(KERN_ERR
+			       "md/raid0:%s: remove inactive devices before converting to RAID0\n",
+			       mdname(mddev));
+			goto abort;
+		}
+		if (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;
+
+		if (mddev->queue)
+			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 (blk_queue_discard(bdev_get_queue(rdev1->bdev)))
+			discard_supported = true;
+	}
+	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);
+	}
+
+	/*
+	 * 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;
+	}
+
+	if (mddev->queue) {
+		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
+		blk_queue_io_opt(mddev->queue,
+				 (mddev->chunk_sectors << 9) * mddev->raid_disks);
+
+		if (!discard_supported)
+			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
+		else
+			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
+	}
+
+	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)];
+}
+
+/**
+ *	raid0_mergeable_bvec -- tell bio layer if two requests can be merged
+ *	@mddev: the md device
+ *	@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 mddev *mddev,
+				struct bvec_merge_data *bvm,
+				struct bio_vec *biovec)
+{
+	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, &sector_offset);
+	rdev = map_sector(mddev, zone, sector, &sector_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 &
+				  ~(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) {
+		printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
+		       mdname(mddev));
+		return -EINVAL;
+	}
+	if (md_check_no_bitmap(mddev))
+		return -EINVAL;
+
+	if (mddev->queue) {
+		blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
+		blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
+		blk_queue_max_discard_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);
+
+	if (mddev->queue) {
+		/* 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;
+	}
+
+	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);
+}
+
+/*
+ * 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_iter.bi_sector & (chunk_sects-1))
+					+ bio_sectors(bio));
+	} else{
+		sector_t sector = bio->bi_iter.bi_sector;
+		return chunk_sects >= (sector_div(sector, chunk_sects)
+						+ bio_sectors(bio));
+	}
+}
+
+static void raid0_make_request(struct mddev *mddev, struct bio *bio)
+{
+	struct strip_zone *zone;
+	struct md_rdev *tmp_dev;
+	struct bio *split;
+
+	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
+		md_flush_request(mddev, bio);
+		return;
+	}
+
+	do {
+		sector_t sector = bio->bi_iter.bi_sector;
+		unsigned chunk_sects = mddev->chunk_sectors;
+
+		unsigned 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->bi_iter.bi_sector;
+
+		if (sectors < bio_sectors(bio)) {
+			split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
+			bio_chain(split, bio);
+		} else {
+			split = bio;
+		}
+
+		zone = find_zone(mddev->private, &sector);
+		tmp_dev = map_sector(mddev, zone, sector, &sector);
+		split->bi_bdev = tmp_dev->bdev;
+		split->bi_iter.bi_sector = sector + zone->dev_start +
+			tmp_dev->data_offset;
+
+		if (unlikely((split->bi_rw & REQ_DISCARD) &&
+			 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
+			/* Just ignore it */
+			bio_endio(split, 0);
+		} else
+			generic_make_request(split);
+	} while (split != bio);
+}
+
+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);
+		}
+		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;
+
+	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->bitmap) {
+		printk(KERN_ERR "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);
+
+		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,
+	.free		= raid0_free,
+	.status		= raid0_status,
+	.size		= raid0_size,
+	.takeover	= raid0_takeover,
+	.quiesce	= raid0_quiesce,
+	.congested	= raid0_congested,
+	.mergeable_bvec	= raid0_mergeable_bvec,
+};
+
+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");