Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1449 insertions, 0 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
new file mode 100644
index 00000000000..a389394b52f
--- /dev/null
+++ b/drivers/md/raid1.c
@@ -0,0 +1,1449 @@
+/*
+ * raid1.c : Multiple Devices driver for Linux
+ *
+ * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
+ *
+ * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
+ *
+ * RAID-1 management functions.
+ *
+ * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
+ *
+ * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
+ * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
+ *
+ * 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/raid/raid1.h>
+
+/*
+ * Number of guaranteed r1bios in case of extreme VM load:
+ */
+#define	NR_RAID1_BIOS 256
+
+static mdk_personality_t raid1_personality;
+
+static void unplug_slaves(mddev_t *mddev);
+
+
+static void * r1bio_pool_alloc(unsigned int __nocast gfp_flags, void *data)
+{
+	struct pool_info *pi = data;
+	r1bio_t *r1_bio;
+	int size = offsetof(r1bio_t, bios[pi->raid_disks]);
+
+	/* allocate a r1bio with room for raid_disks entries in the bios array */
+	r1_bio = kmalloc(size, gfp_flags);
+	if (r1_bio)
+		memset(r1_bio, 0, size);
+	else
+		unplug_slaves(pi->mddev);
+
+	return r1_bio;
+}
+
+static void r1bio_pool_free(void *r1_bio, void *data)
+{
+	kfree(r1_bio);
+}
+
+#define RESYNC_BLOCK_SIZE (64*1024)
+//#define RESYNC_BLOCK_SIZE PAGE_SIZE
+#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
+#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
+#define RESYNC_WINDOW (2048*1024)
+
+static void * r1buf_pool_alloc(unsigned int __nocast gfp_flags, void *data)
+{
+	struct pool_info *pi = data;
+	struct page *page;
+	r1bio_t *r1_bio;
+	struct bio *bio;
+	int i, j;
+
+	r1_bio = r1bio_pool_alloc(gfp_flags, pi);
+	if (!r1_bio) {
+		unplug_slaves(pi->mddev);
+		return NULL;
+	}
+
+	/*
+	 * Allocate bios : 1 for reading, n-1 for writing
+	 */
+	for (j = pi->raid_disks ; j-- ; ) {
+		bio = bio_alloc(gfp_flags, RESYNC_PAGES);
+		if (!bio)
+			goto out_free_bio;
+		r1_bio->bios[j] = bio;
+	}
+	/*
+	 * Allocate RESYNC_PAGES data pages and attach them to
+	 * the first bio;
+	 */
+	bio = r1_bio->bios[0];
+	for (i = 0; i < RESYNC_PAGES; i++) {
+		page = alloc_page(gfp_flags);
+		if (unlikely(!page))
+			goto out_free_pages;
+
+		bio->bi_io_vec[i].bv_page = page;
+	}
+
+	r1_bio->master_bio = NULL;
+
+	return r1_bio;
+
+out_free_pages:
+	for ( ; i > 0 ; i--)
+		__free_page(bio->bi_io_vec[i-1].bv_page);
+out_free_bio:
+	while ( ++j < pi->raid_disks )
+		bio_put(r1_bio->bios[j]);
+	r1bio_pool_free(r1_bio, data);
+	return NULL;
+}
+
+static void r1buf_pool_free(void *__r1_bio, void *data)
+{
+	struct pool_info *pi = data;
+	int i;
+	r1bio_t *r1bio = __r1_bio;
+	struct bio *bio = r1bio->bios[0];
+
+	for (i = 0; i < RESYNC_PAGES; i++) {
+		__free_page(bio->bi_io_vec[i].bv_page);
+		bio->bi_io_vec[i].bv_page = NULL;
+	}
+	for (i=0 ; i < pi->raid_disks; i++)
+		bio_put(r1bio->bios[i]);
+
+	r1bio_pool_free(r1bio, data);
+}
+
+static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
+{
+	int i;
+
+	for (i = 0; i < conf->raid_disks; i++) {
+		struct bio **bio = r1_bio->bios + i;
+		if (*bio)
+			bio_put(*bio);
+		*bio = NULL;
+	}
+}
+
+static inline void free_r1bio(r1bio_t *r1_bio)
+{
+	unsigned long flags;
+
+	conf_t *conf = mddev_to_conf(r1_bio->mddev);
+
+	/*
+	 * Wake up any possible resync thread that waits for the device
+	 * to go idle.
+	 */
+	spin_lock_irqsave(&conf->resync_lock, flags);
+	if (!--conf->nr_pending) {
+		wake_up(&conf->wait_idle);
+		wake_up(&conf->wait_resume);
+	}
+	spin_unlock_irqrestore(&conf->resync_lock, flags);
+
+	put_all_bios(conf, r1_bio);
+	mempool_free(r1_bio, conf->r1bio_pool);
+}
+
+static inline void put_buf(r1bio_t *r1_bio)
+{
+	conf_t *conf = mddev_to_conf(r1_bio->mddev);
+	unsigned long flags;
+
+	mempool_free(r1_bio, conf->r1buf_pool);
+
+	spin_lock_irqsave(&conf->resync_lock, flags);
+	if (!conf->barrier)
+		BUG();
+	--conf->barrier;
+	wake_up(&conf->wait_resume);
+	wake_up(&conf->wait_idle);
+
+	if (!--conf->nr_pending) {
+		wake_up(&conf->wait_idle);
+		wake_up(&conf->wait_resume);
+	}
+	spin_unlock_irqrestore(&conf->resync_lock, flags);
+}
+
+static void reschedule_retry(r1bio_t *r1_bio)
+{
+	unsigned long flags;
+	mddev_t *mddev = r1_bio->mddev;
+	conf_t *conf = mddev_to_conf(mddev);
+
+	spin_lock_irqsave(&conf->device_lock, flags);
+	list_add(&r1_bio->retry_list, &conf->retry_list);
+	spin_unlock_irqrestore(&conf->device_lock, flags);
+
+	md_wakeup_thread(mddev->thread);
+}
+
+/*
+ * raid_end_bio_io() is called when we have finished servicing a mirrored
+ * operation and are ready to return a success/failure code to the buffer
+ * cache layer.
+ */
+static void raid_end_bio_io(r1bio_t *r1_bio)
+{
+	struct bio *bio = r1_bio->master_bio;
+
+	bio_endio(bio, bio->bi_size,
+		test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
+	free_r1bio(r1_bio);
+}
+
+/*
+ * Update disk head position estimator based on IRQ completion info.
+ */
+static inline void update_head_pos(int disk, r1bio_t *r1_bio)
+{
+	conf_t *conf = mddev_to_conf(r1_bio->mddev);
+
+	conf->mirrors[disk].head_position =
+		r1_bio->sector + (r1_bio->sectors);
+}
+
+static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
+{
+	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
+	int mirror;
+	conf_t *conf = mddev_to_conf(r1_bio->mddev);
+
+	if (bio->bi_size)
+		return 1;
+	
+	mirror = r1_bio->read_disk;
+	/*
+	 * this branch is our 'one mirror IO has finished' event handler:
+	 */
+	if (!uptodate)
+		md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
+	else
+		/*
+		 * Set R1BIO_Uptodate in our master bio, so that
+		 * we will return a good error code for to the higher
+		 * levels even if IO on some other mirrored buffer fails.
+		 *
+		 * The 'master' represents the composite IO operation to
+		 * user-side. So if something waits for IO, then it will
+		 * wait for the 'master' bio.
+		 */
+		set_bit(R1BIO_Uptodate, &r1_bio->state);
+
+	update_head_pos(mirror, r1_bio);
+
+	/*
+	 * we have only one bio on the read side
+	 */
+	if (uptodate)
+		raid_end_bio_io(r1_bio);
+	else {
+		/*
+		 * oops, read error:
+		 */
+		char b[BDEVNAME_SIZE];
+		if (printk_ratelimit())
+			printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
+			       bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
+		reschedule_retry(r1_bio);
+	}
+
+	rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
+	return 0;
+}
+
+static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
+{
+	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
+	int mirror;
+	conf_t *conf = mddev_to_conf(r1_bio->mddev);
+
+	if (bio->bi_size)
+		return 1;
+
+	for (mirror = 0; mirror < conf->raid_disks; mirror++)
+		if (r1_bio->bios[mirror] == bio)
+			break;
+
+	/*
+	 * this branch is our 'one mirror IO has finished' event handler:
+	 */
+	if (!uptodate)
+		md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
+	else
+		/*
+		 * Set R1BIO_Uptodate in our master bio, so that
+		 * we will return a good error code for to the higher
+		 * levels even if IO on some other mirrored buffer fails.
+		 *
+		 * The 'master' represents the composite IO operation to
+		 * user-side. So if something waits for IO, then it will
+		 * wait for the 'master' bio.
+		 */
+		set_bit(R1BIO_Uptodate, &r1_bio->state);
+
+	update_head_pos(mirror, r1_bio);
+
+	/*
+	 *
+	 * Let's see if all mirrored write operations have finished
+	 * already.
+	 */
+	if (atomic_dec_and_test(&r1_bio->remaining)) {
+		md_write_end(r1_bio->mddev);
+		raid_end_bio_io(r1_bio);
+	}
+
+	rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
+	return 0;
+}
+
+
+/*
+ * This routine returns the disk from which the requested read should
+ * be done. There is a per-array 'next expected sequential IO' sector
+ * number - if this matches on the next IO then we use the last disk.
+ * There is also a per-disk 'last know head position' sector that is
+ * maintained from IRQ contexts, both the normal and the resync IO
+ * completion handlers update this position correctly. If there is no
+ * perfect sequential match then we pick the disk whose head is closest.
+ *
+ * If there are 2 mirrors in the same 2 devices, performance degrades
+ * because position is mirror, not device based.
+ *
+ * The rdev for the device selected will have nr_pending incremented.
+ */
+static int read_balance(conf_t *conf, r1bio_t *r1_bio)
+{
+	const unsigned long this_sector = r1_bio->sector;
+	int new_disk = conf->last_used, disk = new_disk;
+	const int sectors = r1_bio->sectors;
+	sector_t new_distance, current_distance;
+	mdk_rdev_t *new_rdev, *rdev;
+
+	rcu_read_lock();
+	/*
+	 * Check if it if we can balance. We can balance on the whole
+	 * device if no resync is going on, or below the resync window.
+	 * We take the first readable disk when above the resync window.
+	 */
+ retry:
+	if (conf->mddev->recovery_cp < MaxSector &&
+	    (this_sector + sectors >= conf->next_resync)) {
+		/* Choose the first operation device, for consistancy */
+		new_disk = 0;
+
+		while ((new_rdev=conf->mirrors[new_disk].rdev) == NULL ||
+		       !new_rdev->in_sync) {
+			new_disk++;
+			if (new_disk == conf->raid_disks) {
+				new_disk = -1;
+				break;
+			}
+		}
+		goto rb_out;
+	}
+
+
+	/* make sure the disk is operational */
+	while ((new_rdev=conf->mirrors[new_disk].rdev) == NULL ||
+	       !new_rdev->in_sync) {
+		if (new_disk <= 0)
+			new_disk = conf->raid_disks;
+		new_disk--;
+		if (new_disk == disk) {
+			new_disk = -1;
+			goto rb_out;
+		}
+	}
+	disk = new_disk;
+	/* now disk == new_disk == starting point for search */
+
+	/*
+	 * Don't change to another disk for sequential reads:
+	 */
+	if (conf->next_seq_sect == this_sector)
+		goto rb_out;
+	if (this_sector == conf->mirrors[new_disk].head_position)
+		goto rb_out;
+
+	current_distance = abs(this_sector - conf->mirrors[disk].head_position);
+
+	/* Find the disk whose head is closest */
+
+	do {
+		if (disk <= 0)
+			disk = conf->raid_disks;
+		disk--;
+
+		if ((rdev=conf->mirrors[disk].rdev) == NULL ||
+		    !rdev->in_sync)
+			continue;
+
+		if (!atomic_read(&rdev->nr_pending)) {
+			new_disk = disk;
+			new_rdev = rdev;
+			break;
+		}
+		new_distance = abs(this_sector - conf->mirrors[disk].head_position);
+		if (new_distance < current_distance) {
+			current_distance = new_distance;
+			new_disk = disk;
+			new_rdev = rdev;
+		}
+	} while (disk != conf->last_used);
+
+rb_out:
+
+
+	if (new_disk >= 0) {
+		conf->next_seq_sect = this_sector + sectors;
+		conf->last_used = new_disk;
+		atomic_inc(&new_rdev->nr_pending);
+		if (!new_rdev->in_sync) {
+			/* cannot risk returning a device that failed
+			 * before we inc'ed nr_pending
+			 */
+			atomic_dec(&new_rdev->nr_pending);
+			goto retry;
+		}
+	}
+	rcu_read_unlock();
+
+	return new_disk;
+}
+
+static void unplug_slaves(mddev_t *mddev)
+{
+	conf_t *conf = mddev_to_conf(mddev);
+	int i;
+
+	rcu_read_lock();
+	for (i=0; i<mddev->raid_disks; i++) {
+		mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+		if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
+			request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
+
+			atomic_inc(&rdev->nr_pending);
+			rcu_read_unlock();
+
+			if (r_queue->unplug_fn)
+				r_queue->unplug_fn(r_queue);
+
+			rdev_dec_pending(rdev, mddev);
+			rcu_read_lock();
+		}
+	}
+	rcu_read_unlock();
+}
+
+static void raid1_unplug(request_queue_t *q)
+{
+	unplug_slaves(q->queuedata);
+}
+
+static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
+			     sector_t *error_sector)
+{
+	mddev_t *mddev = q->queuedata;
+	conf_t *conf = mddev_to_conf(mddev);
+	int i, ret = 0;
+
+	rcu_read_lock();
+	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
+		mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+		if (rdev && !rdev->faulty) {
+			struct block_device *bdev = rdev->bdev;
+			request_queue_t *r_queue = bdev_get_queue(bdev);
+
+			if (!r_queue->issue_flush_fn)
+				ret = -EOPNOTSUPP;
+			else {
+				atomic_inc(&rdev->nr_pending);
+				rcu_read_unlock();
+				ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
+							      error_sector);
+				rdev_dec_pending(rdev, mddev);
+				rcu_read_lock();
+			}
+		}
+	}
+	rcu_read_unlock();
+	return ret;
+}
+
+/*
+ * Throttle resync depth, so that we can both get proper overlapping of
+ * requests, but are still able to handle normal requests quickly.
+ */
+#define RESYNC_DEPTH 32
+
+static void device_barrier(conf_t *conf, sector_t sect)
+{
+	spin_lock_irq(&conf->resync_lock);
+	wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume),
+			    conf->resync_lock, unplug_slaves(conf->mddev));
+	
+	if (!conf->barrier++) {
+		wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
+				    conf->resync_lock, unplug_slaves(conf->mddev));
+		if (conf->nr_pending)
+			BUG();
+	}
+	wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH,
+			    conf->resync_lock, unplug_slaves(conf->mddev));
+	conf->next_resync = sect;
+	spin_unlock_irq(&conf->resync_lock);
+}
+
+static int make_request(request_queue_t *q, struct bio * bio)
+{
+	mddev_t *mddev = q->queuedata;
+	conf_t *conf = mddev_to_conf(mddev);
+	mirror_info_t *mirror;
+	r1bio_t *r1_bio;
+	struct bio *read_bio;
+	int i, disks;
+	mdk_rdev_t *rdev;
+
+	/*
+	 * Register the new request and wait if the reconstruction
+	 * thread has put up a bar for new requests.
+	 * Continue immediately if no resync is active currently.
+	 */
+	spin_lock_irq(&conf->resync_lock);
+	wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, );
+	conf->nr_pending++;
+	spin_unlock_irq(&conf->resync_lock);
+
+	if (bio_data_dir(bio)==WRITE) {
+		disk_stat_inc(mddev->gendisk, writes);
+		disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
+	} else {
+		disk_stat_inc(mddev->gendisk, reads);
+		disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
+	}
+
+	/*
+	 * make_request() can abort the operation when READA is being
+	 * used and no empty request is available.
+	 *
+	 */
+	r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
+
+	r1_bio->master_bio = bio;
+	r1_bio->sectors = bio->bi_size >> 9;
+
+	r1_bio->mddev = mddev;
+	r1_bio->sector = bio->bi_sector;
+
+	r1_bio->state = 0;
+
+	if (bio_data_dir(bio) == READ) {
+		/*
+		 * read balancing logic:
+		 */
+		int rdisk = read_balance(conf, r1_bio);
+
+		if (rdisk < 0) {
+			/* couldn't find anywhere to read from */
+			raid_end_bio_io(r1_bio);
+			return 0;
+		}
+		mirror = conf->mirrors + rdisk;
+
+		r1_bio->read_disk = rdisk;
+
+		read_bio = bio_clone(bio, GFP_NOIO);
+
+		r1_bio->bios[rdisk] = read_bio;
+
+		read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
+		read_bio->bi_bdev = mirror->rdev->bdev;
+		read_bio->bi_end_io = raid1_end_read_request;
+		read_bio->bi_rw = READ;
+		read_bio->bi_private = r1_bio;
+
+		generic_make_request(read_bio);
+		return 0;
+	}
+
+	/*
+	 * WRITE:
+	 */
+	/* first select target devices under spinlock and
+	 * inc refcount on their rdev.  Record them by setting
+	 * bios[x] to bio
+	 */
+	disks = conf->raid_disks;
+	rcu_read_lock();
+	for (i = 0;  i < disks; i++) {
+		if ((rdev=conf->mirrors[i].rdev) != NULL &&
+		    !rdev->faulty) {
+			atomic_inc(&rdev->nr_pending);
+			if (rdev->faulty) {
+				atomic_dec(&rdev->nr_pending);
+				r1_bio->bios[i] = NULL;
+			} else
+				r1_bio->bios[i] = bio;
+		} else
+			r1_bio->bios[i] = NULL;
+	}
+	rcu_read_unlock();
+
+	atomic_set(&r1_bio->remaining, 1);
+	md_write_start(mddev);
+	for (i = 0; i < disks; i++) {
+		struct bio *mbio;
+		if (!r1_bio->bios[i])
+			continue;
+
+		mbio = bio_clone(bio, GFP_NOIO);
+		r1_bio->bios[i] = mbio;
+
+		mbio->bi_sector	= r1_bio->sector + conf->mirrors[i].rdev->data_offset;
+		mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
+		mbio->bi_end_io	= raid1_end_write_request;
+		mbio->bi_rw = WRITE;
+		mbio->bi_private = r1_bio;
+
+		atomic_inc(&r1_bio->remaining);
+		generic_make_request(mbio);
+	}
+
+	if (atomic_dec_and_test(&r1_bio->remaining)) {
+		md_write_end(mddev);
+		raid_end_bio_io(r1_bio);
+	}
+
+	return 0;
+}
+
+static void status(struct seq_file *seq, mddev_t *mddev)
+{
+	conf_t *conf = mddev_to_conf(mddev);
+	int i;
+
+	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
+						conf->working_disks);
+	for (i = 0; i < conf->raid_disks; i++)
+		seq_printf(seq, "%s",
+			      conf->mirrors[i].rdev &&
+			      conf->mirrors[i].rdev->in_sync ? "U" : "_");
+	seq_printf(seq, "]");
+}
+
+
+static void error(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+	char b[BDEVNAME_SIZE];
+	conf_t *conf = mddev_to_conf(mddev);
+
+	/*
+	 * If it is not operational, then we have already marked it as dead
+	 * else if it is the last working disks, ignore the error, let the
+	 * next level up know.
+	 * else mark the drive as failed
+	 */
+	if (rdev->in_sync
+	    && conf->working_disks == 1)
+		/*
+		 * Don't fail the drive, act as though we were just a
+		 * normal single drive
+		 */
+		return;
+	if (rdev->in_sync) {
+		mddev->degraded++;
+		conf->working_disks--;
+		/*
+		 * if recovery is running, make sure it aborts.
+		 */
+		set_bit(MD_RECOVERY_ERR, &mddev->recovery);
+	}
+	rdev->in_sync = 0;
+	rdev->faulty = 1;
+	mddev->sb_dirty = 1;
+	printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
+		"	Operation continuing on %d devices\n",
+		bdevname(rdev->bdev,b), conf->working_disks);
+}
+
+static void print_conf(conf_t *conf)
+{
+	int i;
+	mirror_info_t *tmp;
+
+	printk("RAID1 conf printout:\n");
+	if (!conf) {
+		printk("(!conf)\n");
+		return;
+	}
+	printk(" --- wd:%d rd:%d\n", conf->working_disks,
+		conf->raid_disks);
+
+	for (i = 0; i < conf->raid_disks; i++) {
+		char b[BDEVNAME_SIZE];
+		tmp = conf->mirrors + i;
+		if (tmp->rdev)
+			printk(" disk %d, wo:%d, o:%d, dev:%s\n",
+				i, !tmp->rdev->in_sync, !tmp->rdev->faulty,
+				bdevname(tmp->rdev->bdev,b));
+	}
+}
+
+static void close_sync(conf_t *conf)
+{
+	spin_lock_irq(&conf->resync_lock);
+	wait_event_lock_irq(conf->wait_resume, !conf->barrier,
+			    conf->resync_lock, 	unplug_slaves(conf->mddev));
+	spin_unlock_irq(&conf->resync_lock);
+
+	if (conf->barrier) BUG();
+	if (waitqueue_active(&conf->wait_idle)) BUG();
+
+	mempool_destroy(conf->r1buf_pool);
+	conf->r1buf_pool = NULL;
+}
+
+static int raid1_spare_active(mddev_t *mddev)
+{
+	int i;
+	conf_t *conf = mddev->private;
+	mirror_info_t *tmp;
+
+	/*
+	 * Find all failed disks within the RAID1 configuration 
+	 * and mark them readable
+	 */
+	for (i = 0; i < conf->raid_disks; i++) {
+		tmp = conf->mirrors + i;
+		if (tmp->rdev 
+		    && !tmp->rdev->faulty
+		    && !tmp->rdev->in_sync) {
+			conf->working_disks++;
+			mddev->degraded--;
+			tmp->rdev->in_sync = 1;
+		}
+	}
+
+	print_conf(conf);
+	return 0;
+}
+
+
+static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+	conf_t *conf = mddev->private;
+	int found = 0;
+	int mirror;
+	mirror_info_t *p;
+
+	for (mirror=0; mirror < mddev->raid_disks; mirror++)
+		if ( !(p=conf->mirrors+mirror)->rdev) {
+
+			blk_queue_stack_limits(mddev->queue,
+					       rdev->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 (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
+			    mddev->queue->max_sectors > (PAGE_SIZE>>9))
+				blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+
+			p->head_position = 0;
+			rdev->raid_disk = mirror;
+			found = 1;
+			p->rdev = rdev;
+			break;
+		}
+
+	print_conf(conf);
+	return found;
+}
+
+static int raid1_remove_disk(mddev_t *mddev, int number)
+{
+	conf_t *conf = mddev->private;
+	int err = 0;
+	mdk_rdev_t *rdev;
+	mirror_info_t *p = conf->mirrors+ number;
+
+	print_conf(conf);
+	rdev = p->rdev;
+	if (rdev) {
+		if (rdev->in_sync ||
+		    atomic_read(&rdev->nr_pending)) {
+			err = -EBUSY;
+			goto abort;
+		}
+		p->rdev = NULL;
+		synchronize_kernel();
+		if (atomic_read(&rdev->nr_pending)) {
+			/* lost the race, try later */
+			err = -EBUSY;
+			p->rdev = rdev;
+		}
+	}
+abort:
+
+	print_conf(conf);
+	return err;
+}
+
+
+static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
+{
+	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
+	conf_t *conf = mddev_to_conf(r1_bio->mddev);
+
+	if (bio->bi_size)
+		return 1;
+
+	if (r1_bio->bios[r1_bio->read_disk] != bio)
+		BUG();
+	update_head_pos(r1_bio->read_disk, r1_bio);
+	/*
+	 * we have read a block, now it needs to be re-written,
+	 * or re-read if the read failed.
+	 * We don't do much here, just schedule handling by raid1d
+	 */
+	if (!uptodate)
+		md_error(r1_bio->mddev,
+			 conf->mirrors[r1_bio->read_disk].rdev);
+	else
+		set_bit(R1BIO_Uptodate, &r1_bio->state);
+	rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
+	reschedule_retry(r1_bio);
+	return 0;
+}
+
+static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
+{
+	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
+	mddev_t *mddev = r1_bio->mddev;
+	conf_t *conf = mddev_to_conf(mddev);
+	int i;
+	int mirror=0;
+
+	if (bio->bi_size)
+		return 1;
+
+	for (i = 0; i < conf->raid_disks; i++)
+		if (r1_bio->bios[i] == bio) {
+			mirror = i;
+			break;
+		}
+	if (!uptodate)
+		md_error(mddev, conf->mirrors[mirror].rdev);
+	update_head_pos(mirror, r1_bio);
+
+	if (atomic_dec_and_test(&r1_bio->remaining)) {
+		md_done_sync(mddev, r1_bio->sectors, uptodate);
+		put_buf(r1_bio);
+	}
+	rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
+	return 0;
+}
+
+static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
+{
+	conf_t *conf = mddev_to_conf(mddev);
+	int i;
+	int disks = conf->raid_disks;
+	struct bio *bio, *wbio;
+
+	bio = r1_bio->bios[r1_bio->read_disk];
+
+	/*
+	 * schedule writes
+	 */
+	if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
+		/*
+		 * There is no point trying a read-for-reconstruct as
+		 * reconstruct is about to be aborted
+		 */
+		char b[BDEVNAME_SIZE];
+		printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
+			" for block %llu\n",
+			bdevname(bio->bi_bdev,b), 
+			(unsigned long long)r1_bio->sector);
+		md_done_sync(mddev, r1_bio->sectors, 0);
+		put_buf(r1_bio);
+		return;
+	}
+
+	atomic_set(&r1_bio->remaining, 1);
+	for (i = 0; i < disks ; i++) {
+		wbio = r1_bio->bios[i];
+		if (wbio->bi_end_io != end_sync_write)
+			continue;
+
+		atomic_inc(&conf->mirrors[i].rdev->nr_pending);
+		atomic_inc(&r1_bio->remaining);
+		md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
+		generic_make_request(wbio);
+	}
+
+	if (atomic_dec_and_test(&r1_bio->remaining)) {
+		md_done_sync(mddev, r1_bio->sectors, 1);
+		put_buf(r1_bio);
+	}
+}
+
+/*
+ * This is a kernel thread which:
+ *
+ *	1.	Retries failed read operations on working mirrors.
+ *	2.	Updates the raid superblock when problems encounter.
+ *	3.	Performs writes following reads for array syncronising.
+ */
+
+static void raid1d(mddev_t *mddev)
+{
+	r1bio_t *r1_bio;
+	struct bio *bio;
+	unsigned long flags;
+	conf_t *conf = mddev_to_conf(mddev);
+	struct list_head *head = &conf->retry_list;
+	int unplug=0;
+	mdk_rdev_t *rdev;
+
+	md_check_recovery(mddev);
+	md_handle_safemode(mddev);
+	
+	for (;;) {
+		char b[BDEVNAME_SIZE];
+		spin_lock_irqsave(&conf->device_lock, flags);
+		if (list_empty(head))
+			break;
+		r1_bio = list_entry(head->prev, r1bio_t, retry_list);
+		list_del(head->prev);
+		spin_unlock_irqrestore(&conf->device_lock, flags);
+
+		mddev = r1_bio->mddev;
+		conf = mddev_to_conf(mddev);
+		if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
+			sync_request_write(mddev, r1_bio);
+			unplug = 1;
+		} else {
+			int disk;
+			bio = r1_bio->bios[r1_bio->read_disk];
+			if ((disk=read_balance(conf, r1_bio)) == -1) {
+				printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
+				       " read error for block %llu\n",
+				       bdevname(bio->bi_bdev,b),
+				       (unsigned long long)r1_bio->sector);
+				raid_end_bio_io(r1_bio);
+			} else {
+				r1_bio->bios[r1_bio->read_disk] = NULL;
+				r1_bio->read_disk = disk;
+				bio_put(bio);
+				bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
+				r1_bio->bios[r1_bio->read_disk] = bio;
+				rdev = conf->mirrors[disk].rdev;
+				if (printk_ratelimit())
+					printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
+					       " another mirror\n",
+					       bdevname(rdev->bdev,b),
+					       (unsigned long long)r1_bio->sector);
+				bio->bi_sector = r1_bio->sector + rdev->data_offset;
+				bio->bi_bdev = rdev->bdev;
+				bio->bi_end_io = raid1_end_read_request;
+				bio->bi_rw = READ;
+				bio->bi_private = r1_bio;
+				unplug = 1;
+				generic_make_request(bio);
+			}
+		}
+	}
+	spin_unlock_irqrestore(&conf->device_lock, flags);
+	if (unplug)
+		unplug_slaves(mddev);
+}
+
+
+static int init_resync(conf_t *conf)
+{
+	int buffs;
+
+	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
+	if (conf->r1buf_pool)
+		BUG();
+	conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
+					  conf->poolinfo);
+	if (!conf->r1buf_pool)
+		return -ENOMEM;
+	conf->next_resync = 0;
+	return 0;
+}
+
+/*
+ * perform a "sync" on one "block"
+ *
+ * We need to make sure that no normal I/O request - particularly write
+ * requests - conflict with active sync requests.
+ *
+ * This is achieved by tracking pending requests and a 'barrier' concept
+ * that can be installed to exclude normal IO requests.
+ */
+
+static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
+{
+	conf_t *conf = mddev_to_conf(mddev);
+	mirror_info_t *mirror;
+	r1bio_t *r1_bio;
+	struct bio *bio;
+	sector_t max_sector, nr_sectors;
+	int disk;
+	int i;
+	int write_targets = 0;
+
+	if (!conf->r1buf_pool)
+		if (init_resync(conf))
+			return -ENOMEM;
+
+	max_sector = mddev->size << 1;
+	if (sector_nr >= max_sector) {
+		close_sync(conf);
+		return 0;
+	}
+
+	/*
+	 * If there is non-resync activity waiting for us then
+	 * put in a delay to throttle resync.
+	 */
+	if (!go_faster && waitqueue_active(&conf->wait_resume))
+		msleep_interruptible(1000);
+	device_barrier(conf, sector_nr + RESYNC_SECTORS);
+
+	/*
+	 * If reconstructing, and >1 working disc,
+	 * could dedicate one to rebuild and others to
+	 * service read requests ..
+	 */
+	disk = conf->last_used;
+	/* make sure disk is operational */
+
+	while (conf->mirrors[disk].rdev == NULL ||
+	       !conf->mirrors[disk].rdev->in_sync) {
+		if (disk <= 0)
+			disk = conf->raid_disks;
+		disk--;
+		if (disk == conf->last_used)
+			break;
+	}
+	conf->last_used = disk;
+	atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
+
+
+	mirror = conf->mirrors + disk;
+
+	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
+
+	spin_lock_irq(&conf->resync_lock);
+	conf->nr_pending++;
+	spin_unlock_irq(&conf->resync_lock);
+
+	r1_bio->mddev = mddev;
+	r1_bio->sector = sector_nr;
+	set_bit(R1BIO_IsSync, &r1_bio->state);
+	r1_bio->read_disk = disk;
+
+	for (i=0; i < conf->raid_disks; i++) {
+		bio = r1_bio->bios[i];
+
+		/* take from bio_init */
+		bio->bi_next = NULL;
+		bio->bi_flags |= 1 << BIO_UPTODATE;
+		bio->bi_rw = 0;
+		bio->bi_vcnt = 0;
+		bio->bi_idx = 0;
+		bio->bi_phys_segments = 0;
+		bio->bi_hw_segments = 0;
+		bio->bi_size = 0;
+		bio->bi_end_io = NULL;
+		bio->bi_private = NULL;
+
+		if (i == disk) {
+			bio->bi_rw = READ;
+			bio->bi_end_io = end_sync_read;
+		} else if (conf->mirrors[i].rdev &&
+			   !conf->mirrors[i].rdev->faulty &&
+			   (!conf->mirrors[i].rdev->in_sync ||
+			    sector_nr + RESYNC_SECTORS > mddev->recovery_cp)) {
+			bio->bi_rw = WRITE;
+			bio->bi_end_io = end_sync_write;
+			write_targets ++;
+		} else
+			continue;
+		bio->bi_sector = sector_nr + conf->mirrors[i].rdev->data_offset;
+		bio->bi_bdev = conf->mirrors[i].rdev->bdev;
+		bio->bi_private = r1_bio;
+	}
+	if (write_targets == 0) {
+		/* There is nowhere to write, so all non-sync
+		 * drives must be failed - so we are finished
+		 */
+		int rv = max_sector - sector_nr;
+		md_done_sync(mddev, rv, 1);
+		put_buf(r1_bio);
+		rdev_dec_pending(conf->mirrors[disk].rdev, mddev);
+		return rv;
+	}
+
+	nr_sectors = 0;
+	do {
+		struct page *page;
+		int len = PAGE_SIZE;
+		if (sector_nr + (len>>9) > max_sector)
+			len = (max_sector - sector_nr) << 9;
+		if (len == 0)
+			break;
+		for (i=0 ; i < conf->raid_disks; i++) {
+			bio = r1_bio->bios[i];
+			if (bio->bi_end_io) {
+				page = r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page;
+				if (bio_add_page(bio, page, len, 0) == 0) {
+					/* stop here */
+					r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page = page;
+					while (i > 0) {
+						i--;
+						bio = r1_bio->bios[i];
+						if (bio->bi_end_io==NULL) continue;
+						/* remove last page from this bio */
+						bio->bi_vcnt--;
+						bio->bi_size -= len;
+						bio->bi_flags &= ~(1<< BIO_SEG_VALID);
+					}
+					goto bio_full;
+				}
+			}
+		}
+		nr_sectors += len>>9;
+		sector_nr += len>>9;
+	} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
+ bio_full:
+	bio = r1_bio->bios[disk];
+	r1_bio->sectors = nr_sectors;
+
+	md_sync_acct(mirror->rdev->bdev, nr_sectors);
+
+	generic_make_request(bio);
+
+	return nr_sectors;
+}
+
+static int run(mddev_t *mddev)
+{
+	conf_t *conf;
+	int i, j, disk_idx;
+	mirror_info_t *disk;
+	mdk_rdev_t *rdev;
+	struct list_head *tmp;
+
+	if (mddev->level != 1) {
+		printk("raid1: %s: raid level not set to mirroring (%d)\n",
+		       mdname(mddev), mddev->level);
+		goto out;
+	}
+	/*
+	 * copy the already verified devices into our private RAID1
+	 * bookkeeping area. [whatever we allocate in run(),
+	 * should be freed in stop()]
+	 */
+	conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
+	mddev->private = conf;
+	if (!conf)
+		goto out_no_mem;
+
+	memset(conf, 0, sizeof(*conf));
+	conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks, 
+				 GFP_KERNEL);
+	if (!conf->mirrors)
+		goto out_no_mem;
+
+	memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
+
+	conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
+	if (!conf->poolinfo)
+		goto out_no_mem;
+	conf->poolinfo->mddev = mddev;
+	conf->poolinfo->raid_disks = mddev->raid_disks;
+	conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
+					  r1bio_pool_free,
+					  conf->poolinfo);
+	if (!conf->r1bio_pool)
+		goto out_no_mem;
+
+	mddev->queue->unplug_fn = raid1_unplug;
+
+	mddev->queue->issue_flush_fn = raid1_issue_flush;
+
+	ITERATE_RDEV(mddev, rdev, tmp) {
+		disk_idx = rdev->raid_disk;
+		if (disk_idx >= mddev->raid_disks
+		    || disk_idx < 0)
+			continue;
+		disk = conf->mirrors + disk_idx;
+
+		disk->rdev = rdev;
+
+		blk_queue_stack_limits(mddev->queue,
+				       rdev->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 (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
+		    mddev->queue->max_sectors > (PAGE_SIZE>>9))
+			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+
+		disk->head_position = 0;
+		if (!rdev->faulty && rdev->in_sync)
+			conf->working_disks++;
+	}
+	conf->raid_disks = mddev->raid_disks;
+	conf->mddev = mddev;
+	spin_lock_init(&conf->device_lock);
+	INIT_LIST_HEAD(&conf->retry_list);
+	if (conf->working_disks == 1)
+		mddev->recovery_cp = MaxSector;
+
+	spin_lock_init(&conf->resync_lock);
+	init_waitqueue_head(&conf->wait_idle);
+	init_waitqueue_head(&conf->wait_resume);
+
+	if (!conf->working_disks) {
+		printk(KERN_ERR "raid1: no operational mirrors for %s\n",
+			mdname(mddev));
+		goto out_free_conf;
+	}
+
+	mddev->degraded = 0;
+	for (i = 0; i < conf->raid_disks; i++) {
+
+		disk = conf->mirrors + i;
+
+		if (!disk->rdev) {
+			disk->head_position = 0;
+			mddev->degraded++;
+		}
+	}
+
+	/*
+	 * find the first working one and use it as a starting point
+	 * to read balancing.
+	 */
+	for (j = 0; j < conf->raid_disks &&
+		     (!conf->mirrors[j].rdev ||
+		      !conf->mirrors[j].rdev->in_sync) ; j++)
+		/* nothing */;
+	conf->last_used = j;
+
+
+
+	{
+		mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
+		if (!mddev->thread) {
+			printk(KERN_ERR 
+				"raid1: couldn't allocate thread for %s\n", 
+				mdname(mddev));
+			goto out_free_conf;
+		}
+	}
+	printk(KERN_INFO 
+		"raid1: raid set %s active with %d out of %d mirrors\n",
+		mdname(mddev), mddev->raid_disks - mddev->degraded, 
+		mddev->raid_disks);
+	/*
+	 * Ok, everything is just fine now
+	 */
+	mddev->array_size = mddev->size;
+
+	return 0;
+
+out_no_mem:
+	printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
+	       mdname(mddev));
+
+out_free_conf:
+	if (conf) {
+		if (conf->r1bio_pool)
+			mempool_destroy(conf->r1bio_pool);
+		if (conf->mirrors)
+			kfree(conf->mirrors);
+		if (conf->poolinfo)
+			kfree(conf->poolinfo);
+		kfree(conf);
+		mddev->private = NULL;
+	}
+out:
+	return -EIO;
+}
+
+static int stop(mddev_t *mddev)
+{
+	conf_t *conf = mddev_to_conf(mddev);
+
+	md_unregister_thread(mddev->thread);
+	mddev->thread = NULL;
+	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
+	if (conf->r1bio_pool)
+		mempool_destroy(conf->r1bio_pool);
+	if (conf->mirrors)
+		kfree(conf->mirrors);
+	if (conf->poolinfo)
+		kfree(conf->poolinfo);
+	kfree(conf);
+	mddev->private = NULL;
+	return 0;
+}
+
+static int raid1_resize(mddev_t *mddev, sector_t sectors)
+{
+	/* no resync is happening, and there is enough space
+	 * on all devices, so we can resize.
+	 * We need to make sure resync covers any new space.
+	 * If the array is shrinking we should possibly wait until
+	 * any io in the removed space completes, but it hardly seems
+	 * worth it.
+	 */
+	mddev->array_size = sectors>>1;
+	set_capacity(mddev->gendisk, mddev->array_size << 1);
+	mddev->changed = 1;
+	if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) {
+		mddev->recovery_cp = mddev->size << 1;
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	}
+	mddev->size = mddev->array_size;
+	return 0;
+}
+
+static int raid1_reshape(mddev_t *mddev, int raid_disks)
+{
+	/* We need to:
+	 * 1/ resize the r1bio_pool
+	 * 2/ resize conf->mirrors
+	 *
+	 * We allocate a new r1bio_pool if we can.
+	 * Then raise a device barrier and wait until all IO stops.
+	 * Then resize conf->mirrors and swap in the new r1bio pool.
+	 */
+	mempool_t *newpool, *oldpool;
+	struct pool_info *newpoolinfo;
+	mirror_info_t *newmirrors;
+	conf_t *conf = mddev_to_conf(mddev);
+
+	int d;
+
+	for (d= raid_disks; d < conf->raid_disks; d++)
+		if (conf->mirrors[d].rdev)
+			return -EBUSY;
+
+	newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
+	if (!newpoolinfo)
+		return -ENOMEM;
+	newpoolinfo->mddev = mddev;
+	newpoolinfo->raid_disks = raid_disks;
+
+	newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
+				 r1bio_pool_free, newpoolinfo);
+	if (!newpool) {
+		kfree(newpoolinfo);
+		return -ENOMEM;
+	}
+	newmirrors = kmalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
+	if (!newmirrors) {
+		kfree(newpoolinfo);
+		mempool_destroy(newpool);
+		return -ENOMEM;
+	}
+	memset(newmirrors, 0, sizeof(struct mirror_info)*raid_disks);
+
+	spin_lock_irq(&conf->resync_lock);
+	conf->barrier++;
+	wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
+			    conf->resync_lock, unplug_slaves(mddev));
+	spin_unlock_irq(&conf->resync_lock);
+
+	/* ok, everything is stopped */
+	oldpool = conf->r1bio_pool;
+	conf->r1bio_pool = newpool;
+	for (d=0; d < raid_disks && d < conf->raid_disks; d++)
+		newmirrors[d] = conf->mirrors[d];
+	kfree(conf->mirrors);
+	conf->mirrors = newmirrors;
+	kfree(conf->poolinfo);
+	conf->poolinfo = newpoolinfo;
+
+	mddev->degraded += (raid_disks - conf->raid_disks);
+	conf->raid_disks = mddev->raid_disks = raid_disks;
+
+	spin_lock_irq(&conf->resync_lock);
+	conf->barrier--;
+	spin_unlock_irq(&conf->resync_lock);
+	wake_up(&conf->wait_resume);
+	wake_up(&conf->wait_idle);
+
+
+	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	md_wakeup_thread(mddev->thread);
+
+	mempool_destroy(oldpool);
+	return 0;
+}
+
+
+static mdk_personality_t raid1_personality =
+{
+	.name		= "raid1",
+	.owner		= THIS_MODULE,
+	.make_request	= make_request,
+	.run		= run,
+	.stop		= stop,
+	.status		= status,
+	.error_handler	= error,
+	.hot_add_disk	= raid1_add_disk,
+	.hot_remove_disk= raid1_remove_disk,
+	.spare_active	= raid1_spare_active,
+	.sync_request	= sync_request,
+	.resize		= raid1_resize,
+	.reshape	= raid1_reshape,
+};
+
+static int __init raid_init(void)
+{
+	return register_md_personality(RAID1, &raid1_personality);
+}
+
+static void raid_exit(void)
+{
+	unregister_md_personality(RAID1);
+}
+
+module_init(raid_init);
+module_exit(raid_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("md-personality-3"); /* RAID1 */