raid10.c 58.2 KB
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/*
 * raid10.c : Multiple Devices driver for Linux
 *
 * Copyright (C) 2000-2004 Neil Brown
 *
 * RAID-10 support for md.
 *
 * Base on code in raid1.c.  See raid1.c for futher copyright information.
 *
 *
 * 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.
 */

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#include "dm-bio-list.h"
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#include <linux/raid/raid10.h>
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#include <linux/raid/bitmap.h>
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/*
 * RAID10 provides a combination of RAID0 and RAID1 functionality.
 * The layout of data is defined by
 *    chunk_size
 *    raid_disks
 *    near_copies (stored in low byte of layout)
 *    far_copies (stored in second byte of layout)
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 *    far_offset (stored in bit 16 of layout )
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 *
 * The data to be stored is divided into chunks using chunksize.
 * Each device is divided into far_copies sections.
 * In each section, chunks are laid out in a style similar to raid0, but
 * near_copies copies of each chunk is stored (each on a different drive).
 * The starting device for each section is offset near_copies from the starting
 * device of the previous section.
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 * Thus they are (near_copies*far_copies) of each chunk, and each is on a different
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 * drive.
 * near_copies and far_copies must be at least one, and their product is at most
 * raid_disks.
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 *
 * If far_offset is true, then the far_copies are handled a bit differently.
 * The copies are still in different stripes, but instead of be very far apart
 * on disk, there are adjacent stripes.
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 */

/*
 * Number of guaranteed r10bios in case of extreme VM load:
 */
#define	NR_RAID10_BIOS 256

static void unplug_slaves(mddev_t *mddev);

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static void allow_barrier(conf_t *conf);
static void lower_barrier(conf_t *conf);

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static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
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{
	conf_t *conf = data;
	r10bio_t *r10_bio;
	int size = offsetof(struct r10bio_s, devs[conf->copies]);

	/* allocate a r10bio with room for raid_disks entries in the bios array */
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	r10_bio = kzalloc(size, gfp_flags);
	if (!r10_bio)
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		unplug_slaves(conf->mddev);

	return r10_bio;
}

static void r10bio_pool_free(void *r10_bio, void *data)
{
	kfree(r10_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)

/*
 * When performing a resync, we need to read and compare, so
 * we need as many pages are there are copies.
 * When performing a recovery, we need 2 bios, one for read,
 * one for write (we recover only one drive per r10buf)
 *
 */
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static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
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{
	conf_t *conf = data;
	struct page *page;
	r10bio_t *r10_bio;
	struct bio *bio;
	int i, j;
	int nalloc;

	r10_bio = r10bio_pool_alloc(gfp_flags, conf);
	if (!r10_bio) {
		unplug_slaves(conf->mddev);
		return NULL;
	}

	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
		nalloc = conf->copies; /* resync */
	else
		nalloc = 2; /* recovery */

	/*
	 * Allocate bios.
	 */
	for (j = nalloc ; j-- ; ) {
		bio = bio_alloc(gfp_flags, RESYNC_PAGES);
		if (!bio)
			goto out_free_bio;
		r10_bio->devs[j].bio = bio;
	}
	/*
	 * Allocate RESYNC_PAGES data pages and attach them
	 * where needed.
	 */
	for (j = 0 ; j < nalloc; j++) {
		bio = r10_bio->devs[j].bio;
		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;
		}
	}

	return r10_bio;

out_free_pages:
	for ( ; i > 0 ; i--)
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		safe_put_page(bio->bi_io_vec[i-1].bv_page);
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	while (j--)
		for (i = 0; i < RESYNC_PAGES ; i++)
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			safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
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	j = -1;
out_free_bio:
	while ( ++j < nalloc )
		bio_put(r10_bio->devs[j].bio);
	r10bio_pool_free(r10_bio, conf);
	return NULL;
}

static void r10buf_pool_free(void *__r10_bio, void *data)
{
	int i;
	conf_t *conf = data;
	r10bio_t *r10bio = __r10_bio;
	int j;

	for (j=0; j < conf->copies; j++) {
		struct bio *bio = r10bio->devs[j].bio;
		if (bio) {
			for (i = 0; i < RESYNC_PAGES; i++) {
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				safe_put_page(bio->bi_io_vec[i].bv_page);
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				bio->bi_io_vec[i].bv_page = NULL;
			}
			bio_put(bio);
		}
	}
	r10bio_pool_free(r10bio, conf);
}

static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)
{
	int i;

	for (i = 0; i < conf->copies; i++) {
		struct bio **bio = & r10_bio->devs[i].bio;
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		if (*bio && *bio != IO_BLOCKED)
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			bio_put(*bio);
		*bio = NULL;
	}
}

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static void free_r10bio(r10bio_t *r10_bio)
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{
	conf_t *conf = mddev_to_conf(r10_bio->mddev);

	/*
	 * Wake up any possible resync thread that waits for the device
	 * to go idle.
	 */
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	allow_barrier(conf);
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	put_all_bios(conf, r10_bio);
	mempool_free(r10_bio, conf->r10bio_pool);
}

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static void put_buf(r10bio_t *r10_bio)
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{
	conf_t *conf = mddev_to_conf(r10_bio->mddev);

	mempool_free(r10_bio, conf->r10buf_pool);

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	lower_barrier(conf);
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}

static void reschedule_retry(r10bio_t *r10_bio)
{
	unsigned long flags;
	mddev_t *mddev = r10_bio->mddev;
	conf_t *conf = mddev_to_conf(mddev);

	spin_lock_irqsave(&conf->device_lock, flags);
	list_add(&r10_bio->retry_list, &conf->retry_list);
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	conf->nr_queued ++;
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	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(r10bio_t *r10_bio)
{
	struct bio *bio = r10_bio->master_bio;

	bio_endio(bio, bio->bi_size,
		test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO);
	free_r10bio(r10_bio);
}

/*
 * Update disk head position estimator based on IRQ completion info.
 */
static inline void update_head_pos(int slot, r10bio_t *r10_bio)
{
	conf_t *conf = mddev_to_conf(r10_bio->mddev);

	conf->mirrors[r10_bio->devs[slot].devnum].head_position =
		r10_bio->devs[slot].addr + (r10_bio->sectors);
}

static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
	int slot, dev;
	conf_t *conf = mddev_to_conf(r10_bio->mddev);

	if (bio->bi_size)
		return 1;

	slot = r10_bio->read_slot;
	dev = r10_bio->devs[slot].devnum;
	/*
	 * this branch is our 'one mirror IO has finished' event handler:
	 */
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	update_head_pos(slot, r10_bio);

	if (uptodate) {
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		/*
		 * Set R10BIO_Uptodate in our master bio, so that
		 * we will return a good error code 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(R10BIO_Uptodate, &r10_bio->state);
		raid_end_bio_io(r10_bio);
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	} else {
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		/*
		 * oops, read error:
		 */
		char b[BDEVNAME_SIZE];
		if (printk_ratelimit())
			printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n",
			       bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector);
		reschedule_retry(r10_bio);
	}

	rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
	return 0;
}

static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
	int slot, dev;
	conf_t *conf = mddev_to_conf(r10_bio->mddev);

	if (bio->bi_size)
		return 1;

	for (slot = 0; slot < conf->copies; slot++)
		if (r10_bio->devs[slot].bio == bio)
			break;
	dev = r10_bio->devs[slot].devnum;

	/*
	 * this branch is our 'one mirror IO has finished' event handler:
	 */
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	if (!uptodate) {
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		md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
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		/* an I/O failed, we can't clear the bitmap */
		set_bit(R10BIO_Degraded, &r10_bio->state);
	} else
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		/*
		 * Set R10BIO_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(R10BIO_Uptodate, &r10_bio->state);

	update_head_pos(slot, r10_bio);

	/*
	 *
	 * Let's see if all mirrored write operations have finished
	 * already.
	 */
	if (atomic_dec_and_test(&r10_bio->remaining)) {
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		/* clear the bitmap if all writes complete successfully */
		bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
				r10_bio->sectors,
				!test_bit(R10BIO_Degraded, &r10_bio->state),
				0);
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		md_write_end(r10_bio->mddev);
		raid_end_bio_io(r10_bio);
	}

	rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
	return 0;
}


/*
 * RAID10 layout manager
 * Aswell as the chunksize and raid_disks count, there are two
 * parameters: near_copies and far_copies.
 * near_copies * far_copies must be <= raid_disks.
 * Normally one of these will be 1.
 * If both are 1, we get raid0.
 * If near_copies == raid_disks, we get raid1.
 *
 * Chunks are layed out in raid0 style with near_copies copies of the
 * first chunk, followed by near_copies copies of the next chunk and
 * so on.
 * If far_copies > 1, then after 1/far_copies of the array has been assigned
 * as described above, we start again with a device offset of near_copies.
 * So we effectively have another copy of the whole array further down all
 * the drives, but with blocks on different drives.
 * With this layout, and block is never stored twice on the one device.
 *
 * raid10_find_phys finds the sector offset of a given virtual sector
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 * on each device that it is on.
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 *
 * raid10_find_virt does the reverse mapping, from a device and a
 * sector offset to a virtual address
 */

static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio)
{
	int n,f;
	sector_t sector;
	sector_t chunk;
	sector_t stripe;
	int dev;

	int slot = 0;

	/* now calculate first sector/dev */
	chunk = r10bio->sector >> conf->chunk_shift;
	sector = r10bio->sector & conf->chunk_mask;

	chunk *= conf->near_copies;
	stripe = chunk;
	dev = sector_div(stripe, conf->raid_disks);
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	if (conf->far_offset)
		stripe *= conf->far_copies;
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	sector += stripe << conf->chunk_shift;

	/* and calculate all the others */
	for (n=0; n < conf->near_copies; n++) {
		int d = dev;
		sector_t s = sector;
		r10bio->devs[slot].addr = sector;
		r10bio->devs[slot].devnum = d;
		slot++;

		for (f = 1; f < conf->far_copies; f++) {
			d += conf->near_copies;
			if (d >= conf->raid_disks)
				d -= conf->raid_disks;
			s += conf->stride;
			r10bio->devs[slot].devnum = d;
			r10bio->devs[slot].addr = s;
			slot++;
		}
		dev++;
		if (dev >= conf->raid_disks) {
			dev = 0;
			sector += (conf->chunk_mask + 1);
		}
	}
	BUG_ON(slot != conf->copies);
}

static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
{
	sector_t offset, chunk, vchunk;

	offset = sector & conf->chunk_mask;
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	if (conf->far_offset) {
		int fc;
		chunk = sector >> conf->chunk_shift;
		fc = sector_div(chunk, conf->far_copies);
		dev -= fc * conf->near_copies;
		if (dev < 0)
			dev += conf->raid_disks;
	} else {
		while (sector > conf->stride) {
			sector -= conf->stride;
			if (dev < conf->near_copies)
				dev += conf->raid_disks - conf->near_copies;
			else
				dev -= conf->near_copies;
		}
		chunk = sector >> conf->chunk_shift;
	}
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	vchunk = chunk * conf->raid_disks + dev;
	sector_div(vchunk, conf->near_copies);
	return (vchunk << conf->chunk_shift) + offset;
}

/**
 *	raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
 *	@q: request queue
 *	@bio: the buffer head that's been built up so far
 *	@biovec: the request that could be merged to it.
 *
 *	Return amount of bytes we can accept at this offset
 *      If near_copies == raid_disk, there are no striping issues,
 *      but in that case, the function isn't called at all.
 */
static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio,
				struct bio_vec *bio_vec)
{
	mddev_t *mddev = q->queuedata;
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
	int max;
	unsigned int chunk_sectors = mddev->chunk_size >> 9;
	unsigned int bio_sectors = bio->bi_size >> 9;

	max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
	if (max < 0) max = 0; /* bio_add cannot handle a negative return */
	if (max <= bio_vec->bv_len && bio_sectors == 0)
		return bio_vec->bv_len;
	else
		return max;
}

/*
 * 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.
 */

/*
 * FIXME: possibly should rethink readbalancing and do it differently
 * depending on near_copies / far_copies geometry.
 */
static int read_balance(conf_t *conf, r10bio_t *r10_bio)
{
	const unsigned long this_sector = r10_bio->sector;
	int disk, slot, nslot;
	const int sectors = r10_bio->sectors;
	sector_t new_distance, current_distance;
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	mdk_rdev_t *rdev;
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	raid10_find_phys(conf, r10_bio);
	rcu_read_lock();
	/*
	 * Check if we can balance. We can balance on the whole
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	 * device if no resync is going on (recovery is ok), or below
	 * the resync window. We take the first readable disk when
	 * above the resync window.
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	 */
	if (conf->mddev->recovery_cp < MaxSector
	    && (this_sector + sectors >= conf->next_resync)) {
		/* make sure that disk is operational */
		slot = 0;
		disk = r10_bio->devs[slot].devnum;

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		while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
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		       r10_bio->devs[slot].bio == IO_BLOCKED ||
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		       !test_bit(In_sync, &rdev->flags)) {
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			slot++;
			if (slot == conf->copies) {
				slot = 0;
				disk = -1;
				break;
			}
			disk = r10_bio->devs[slot].devnum;
		}
		goto rb_out;
	}


	/* make sure the disk is operational */
	slot = 0;
	disk = r10_bio->devs[slot].devnum;
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	while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
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	       r10_bio->devs[slot].bio == IO_BLOCKED ||
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	       !test_bit(In_sync, &rdev->flags)) {
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		slot ++;
		if (slot == conf->copies) {
			disk = -1;
			goto rb_out;
		}
		disk = r10_bio->devs[slot].devnum;
	}


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	current_distance = abs(r10_bio->devs[slot].addr -
			       conf->mirrors[disk].head_position);
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	/* Find the disk whose head is closest */

	for (nslot = slot; nslot < conf->copies; nslot++) {
		int ndisk = r10_bio->devs[nslot].devnum;


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		if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL ||
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		    r10_bio->devs[nslot].bio == IO_BLOCKED ||
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		    !test_bit(In_sync, &rdev->flags))
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			continue;

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		/* This optimisation is debatable, and completely destroys
		 * sequential read speed for 'far copies' arrays.  So only
		 * keep it for 'near' arrays, and review those later.
		 */
		if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) {
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			disk = ndisk;
			slot = nslot;
			break;
		}
		new_distance = abs(r10_bio->devs[nslot].addr -
				   conf->mirrors[ndisk].head_position);
		if (new_distance < current_distance) {
			current_distance = new_distance;
			disk = ndisk;
			slot = nslot;
		}
	}

rb_out:
	r10_bio->read_slot = slot;
/*	conf->next_seq_sect = this_sector + sectors;*/

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	if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL)
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		atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
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	else
		disk = -1;
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	rcu_read_unlock();

	return 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++) {
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		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
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		if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
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			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 raid10_unplug(request_queue_t *q)
{
615 616
	mddev_t *mddev = q->queuedata;

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	unplug_slaves(q->queuedata);
618
	md_wakeup_thread(mddev->thread);
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}

static int raid10_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++) {
630
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
631
		if (rdev && !test_bit(Faulty, &rdev->flags)) {
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			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;
}

651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670
/* Barriers....
 * Sometimes we need to suspend IO while we do something else,
 * either some resync/recovery, or reconfigure the array.
 * To do this we raise a 'barrier'.
 * The 'barrier' is a counter that can be raised multiple times
 * to count how many activities are happening which preclude
 * normal IO.
 * We can only raise the barrier if there is no pending IO.
 * i.e. if nr_pending == 0.
 * We choose only to raise the barrier if no-one is waiting for the
 * barrier to go down.  This means that as soon as an IO request
 * is ready, no other operations which require a barrier will start
 * until the IO request has had a chance.
 *
 * So: regular IO calls 'wait_barrier'.  When that returns there
 *    is no backgroup IO happening,  It must arrange to call
 *    allow_barrier when it has finished its IO.
 * backgroup IO calls must call raise_barrier.  Once that returns
 *    there is no normal IO happeing.  It must arrange to call
 *    lower_barrier when the particular background IO completes.
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 */
#define RESYNC_DEPTH 32

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static void raise_barrier(conf_t *conf, int force)
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{
676
	BUG_ON(force && !conf->barrier);
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	spin_lock_irq(&conf->resync_lock);
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679 680
	/* Wait until no block IO is waiting (unless 'force') */
	wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713
			    conf->resync_lock,
			    raid10_unplug(conf->mddev->queue));

	/* block any new IO from starting */
	conf->barrier++;

	/* No wait for all pending IO to complete */
	wait_event_lock_irq(conf->wait_barrier,
			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
			    conf->resync_lock,
			    raid10_unplug(conf->mddev->queue));

	spin_unlock_irq(&conf->resync_lock);
}

static void lower_barrier(conf_t *conf)
{
	unsigned long flags;
	spin_lock_irqsave(&conf->resync_lock, flags);
	conf->barrier--;
	spin_unlock_irqrestore(&conf->resync_lock, flags);
	wake_up(&conf->wait_barrier);
}

static void wait_barrier(conf_t *conf)
{
	spin_lock_irq(&conf->resync_lock);
	if (conf->barrier) {
		conf->nr_waiting++;
		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
				    conf->resync_lock,
				    raid10_unplug(conf->mddev->queue));
		conf->nr_waiting--;
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	}
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	conf->nr_pending++;
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	spin_unlock_irq(&conf->resync_lock);
}

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static void allow_barrier(conf_t *conf)
{
	unsigned long flags;
	spin_lock_irqsave(&conf->resync_lock, flags);
	conf->nr_pending--;
	spin_unlock_irqrestore(&conf->resync_lock, flags);
	wake_up(&conf->wait_barrier);
}

728 729 730
static void freeze_array(conf_t *conf)
{
	/* stop syncio and normal IO and wait for everything to
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	 * go quiet.
732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754
	 * We increment barrier and nr_waiting, and then
	 * wait until barrier+nr_pending match nr_queued+2
	 */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier++;
	conf->nr_waiting++;
	wait_event_lock_irq(conf->wait_barrier,
			    conf->barrier+conf->nr_pending == conf->nr_queued+2,
			    conf->resync_lock,
			    raid10_unplug(conf->mddev->queue));
	spin_unlock_irq(&conf->resync_lock);
}

static void unfreeze_array(conf_t *conf)
{
	/* reverse the effect of the freeze */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier--;
	conf->nr_waiting--;
	wake_up(&conf->wait_barrier);
	spin_unlock_irq(&conf->resync_lock);
}

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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;
	r10bio_t *r10_bio;
	struct bio *read_bio;
	int i;
	int chunk_sects = conf->chunk_mask + 1;
764
	const int rw = bio_data_dir(bio);
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	struct bio_list bl;
	unsigned long flags;
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768 769 770 771 772
	if (unlikely(bio_barrier(bio))) {
		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
		return 0;
	}

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	/* If this request crosses a chunk boundary, we need to
	 * split it.  This will only happen for 1 PAGE (or less) requests.
	 */
	if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9)
		      > chunk_sects &&
		    conf->near_copies < conf->raid_disks)) {
		struct bio_pair *bp;
		/* Sanity check -- queue functions should prevent this happening */
		if (bio->bi_vcnt != 1 ||
		    bio->bi_idx != 0)
			goto bad_map;
		/* This is a one page bio that upper layers
		 * refuse to split for us, so we need to split it.
		 */
		bp = bio_split(bio, bio_split_pool,
			       chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
		if (make_request(q, &bp->bio1))
			generic_make_request(&bp->bio1);
		if (make_request(q, &bp->bio2))
			generic_make_request(&bp->bio2);

		bio_pair_release(bp);
		return 0;
	bad_map:
		printk("raid10_make_request bug: can't convert block across chunks"
		       " or bigger than %dk %llu %d\n", chunk_sects/2,
		       (unsigned long long)bio->bi_sector, bio->bi_size >> 10);

		bio_io_error(bio, bio->bi_size);
		return 0;
	}

805
	md_write_start(mddev, bio);
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	/*
	 * 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.
	 */
812
	wait_barrier(conf);
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	disk_stat_inc(mddev->gendisk, ios[rw]);
	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
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	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);

	r10_bio->master_bio = bio;
	r10_bio->sectors = bio->bi_size >> 9;

	r10_bio->mddev = mddev;
	r10_bio->sector = bio->bi_sector;
824
	r10_bio->state = 0;
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826
	if (rw == READ) {
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		/*
		 * read balancing logic:
		 */
		int disk = read_balance(conf, r10_bio);
		int slot = r10_bio->read_slot;
		if (disk < 0) {
			raid_end_bio_io(r10_bio);
			return 0;
		}
		mirror = conf->mirrors + disk;

		read_bio = bio_clone(bio, GFP_NOIO);

		r10_bio->devs[slot].bio = read_bio;

		read_bio->bi_sector = r10_bio->devs[slot].addr +
			mirror->rdev->data_offset;
		read_bio->bi_bdev = mirror->rdev->bdev;
		read_bio->bi_end_io = raid10_end_read_request;
		read_bio->bi_rw = READ;
		read_bio->bi_private = r10_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
	 */
	raid10_find_phys(conf, r10_bio);
	rcu_read_lock();
	for (i = 0;  i < conf->copies; i++) {
		int d = r10_bio->devs[i].devnum;
864 865
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
		if (rdev &&
866
		    !test_bit(Faulty, &rdev->flags)) {
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			atomic_inc(&rdev->nr_pending);
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			r10_bio->devs[i].bio = bio;
869
		} else {
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			r10_bio->devs[i].bio = NULL;
871 872
			set_bit(R10BIO_Degraded, &r10_bio->state);
		}
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	}
	rcu_read_unlock();

876
	atomic_set(&r10_bio->remaining, 0);
877

878
	bio_list_init(&bl);
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	for (i = 0; i < conf->copies; i++) {
		struct bio *mbio;
		int d = r10_bio->devs[i].devnum;
		if (!r10_bio->devs[i].bio)
			continue;

		mbio = bio_clone(bio, GFP_NOIO);
		r10_bio->devs[i].bio = mbio;

		mbio->bi_sector	= r10_bio->devs[i].addr+
			conf->mirrors[d].rdev->data_offset;
		mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
		mbio->bi_end_io	= raid10_end_write_request;
		mbio->bi_rw = WRITE;
		mbio->bi_private = r10_bio;

		atomic_inc(&r10_bio->remaining);
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		bio_list_add(&bl, mbio);
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	}

899 900 901 902 903
	bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0);
	spin_lock_irqsave(&conf->device_lock, flags);
	bio_list_merge(&conf->pending_bio_list, &bl);
	blk_plug_device(mddev->queue);
	spin_unlock_irqrestore(&conf->device_lock, flags);
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	return 0;
}

static void status(struct seq_file *seq, mddev_t *mddev)
{
	conf_t *conf = mddev_to_conf(mddev);
	int i;

	if (conf->near_copies < conf->raid_disks)
		seq_printf(seq, " %dK chunks", mddev->chunk_size/1024);
	if (conf->near_copies > 1)
		seq_printf(seq, " %d near-copies", conf->near_copies);
917 918 919 920 921 922
	if (conf->far_copies > 1) {
		if (conf->far_offset)
			seq_printf(seq, " %d offset-copies", conf->far_copies);
		else
			seq_printf(seq, " %d far-copies", conf->far_copies);
	}
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	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
924
					conf->raid_disks - mddev->degraded);
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	for (i = 0; i < conf->raid_disks; i++)
		seq_printf(seq, "%s",
			      conf->mirrors[i].rdev &&
928
			      test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
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	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
	 */
943
	if (test_bit(In_sync, &rdev->flags)
944
	    && conf->raid_disks-mddev->degraded == 1)
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		/*
		 * Don't fail the drive, just return an IO error.
		 * The test should really be more sophisticated than
		 * "working_disks == 1", but it isn't critical, and
		 * can wait until we do more sophisticated "is the drive
		 * really dead" tests...
		 */
		return;
953
	if (test_bit(In_sync, &rdev->flags)) {
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		mddev->degraded++;
		/*
		 * if recovery is running, make sure it aborts.
		 */
		set_bit(MD_RECOVERY_ERR, &mddev->recovery);
	}
960 961
	clear_bit(In_sync, &rdev->flags);
	set_bit(Faulty, &rdev->flags);
962
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
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	printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"
		"	Operation continuing on %d devices\n",
965
		bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
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}

static void print_conf(conf_t *conf)
{
	int i;
	mirror_info_t *tmp;

	printk("RAID10 conf printout:\n");
	if (!conf) {
		printk("(!conf)\n");
		return;
	}
978
	printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
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		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",
986 987
				i, !test_bit(In_sync, &tmp->rdev->flags),
			        !test_bit(Faulty, &tmp->rdev->flags),
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				bdevname(tmp->rdev->bdev,b));
	}
}

static void close_sync(conf_t *conf)
{
994 995
	wait_barrier(conf);
	allow_barrier(conf);
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	mempool_destroy(conf->r10buf_pool);
	conf->r10buf_pool = NULL;
}

1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
/* check if there are enough drives for
 * every block to appear on atleast one
 */
static int enough(conf_t *conf)
{
	int first = 0;

	do {
		int n = conf->copies;
		int cnt = 0;
		while (n--) {
			if (conf->mirrors[first].rdev)
				cnt++;
			first = (first+1) % conf->raid_disks;
		}
		if (cnt == 0)
			return 0;
	} while (first != 0);
	return 1;
}

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static int raid10_spare_active(mddev_t *mddev)
{
	int i;
	conf_t *conf = mddev->private;
	mirror_info_t *tmp;

	/*
	 * Find all non-in_sync disks within the RAID10 configuration
	 * and mark them in_sync
	 */
	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->mirrors + i;
		if (tmp->rdev
1035 1036
		    && !test_bit(Faulty, &tmp->rdev->flags)
		    && !test_bit(In_sync, &tmp->rdev->flags)) {
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			mddev->degraded--;
1038
			set_bit(In_sync, &tmp->rdev->flags);
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		}
	}

	print_conf(conf);
	return 0;
}


static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
	conf_t *conf = mddev->private;
	int found = 0;
	int mirror;
	mirror_info_t *p;

	if (mddev->recovery_cp < MaxSector)
		/* only hot-add to in-sync arrays, as recovery is
		 * very different from resync
		 */
		return 0;
1059 1060
	if (!enough(conf))
		return 0;
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1062 1063 1064 1065 1066 1067
	if (rdev->saved_raid_disk >= 0 &&
	    conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
		mirror = rdev->saved_raid_disk;
	else
		mirror = 0;
	for ( ; mirror < mddev->raid_disks; mirror++)
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		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))
				mddev->queue->max_sectors = (PAGE_SIZE>>9);

			p->head_position = 0;
			rdev->raid_disk = mirror;
			found = 1;
1083 1084
			if (rdev->saved_raid_disk != mirror)
				conf->fullsync = 1;
1085
			rcu_assign_pointer(p->rdev, rdev);
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			break;
		}

	print_conf(conf);
	return found;
}

static int raid10_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) {
1103
		if (test_bit(In_sync, &rdev->flags) ||
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		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
		p->rdev = NULL;
1109
		synchronize_rcu();
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		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)
{
	r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
	conf_t *conf = mddev_to_conf(r10_bio->mddev);
	int i,d;

	if (bio->bi_size)
		return 1;

	for (i=0; i<conf->copies; i++)
		if (r10_bio->devs[i].bio == bio)
			break;
1135
	BUG_ON(i == conf->copies);
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	update_head_pos(i, r10_bio);
	d = r10_bio->devs[i].devnum;
1138 1139 1140

	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
		set_bit(R10BIO_Uptodate, &r10_bio->state);
1141 1142 1143 1144 1145 1146 1147
	else {
		atomic_add(r10_bio->sectors,
			   &conf->mirrors[d].rdev->corrected_errors);
		if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
			md_error(r10_bio->mddev,
				 conf->mirrors[d].rdev);
	}
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	/* for reconstruct, we always reschedule after a read.
	 * for resync, only after all reads
	 */
	if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
	    atomic_dec_and_test(&r10_bio->remaining)) {
		/* we have read all the blocks,
		 * do the comparison in process context in raid10d
		 */
		reschedule_retry(r10_bio);
	}
	rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
	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);
	r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
	mddev_t *mddev = r10_bio->mddev;
	conf_t *conf = mddev_to_conf(mddev);
	int i,d;

	if (bio->bi_size)
		return 1;

	for (i = 0; i < conf->copies; i++)
		if (r10_bio->devs[i].bio == bio)
			break;
	d = r10_bio->devs[i].devnum;

	if (!uptodate)
		md_error(mddev, conf->mirrors[d].rdev);
	update_head_pos(i, r10_bio);

	while (atomic_dec_and_test(&r10_bio->remaining)) {
		if (r10_bio->master_bio == NULL) {
			/* the primary of several recovery bios */
			md_done_sync(mddev, r10_bio->sectors, 1);
			put_buf(r10_bio);
			break;
		} else {
			r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio;
			put_buf(r10_bio);
			r10_bio = r10_bio2;
		}
	}
	rdev_dec_pending(conf->mirrors[d].rdev, mddev);
	return 0;
}

/*
 * Note: sync and recover and handled very differently for raid10
 * This code is for resync.
 * For resync, we read through virtual addresses and read all blocks.
 * If there is any error, we schedule a write.  The lowest numbered
 * drive is authoritative.
 * However requests come for physical address, so we need to map.
 * For every physical address there are raid_disks/copies virtual addresses,
 * which is always are least one, but is not necessarly an integer.
 * This means that a physical address can span multiple chunks, so we may
 * have to submit multiple io requests for a single sync request.
 */
/*
 * We check if all blocks are in-sync and only write to blocks that
 * aren't in sync
 */
static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio)
{
	conf_t *conf = mddev_to_conf(mddev);
	int i, first;
	struct bio *tbio, *fbio;

	atomic_set(&r10_bio->remaining, 1);

	/* find the first device with a block */
	for (i=0; i<conf->copies; i++)
		if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
			break;

	if (i == conf->copies)
		goto done;

	first = i;
	fbio = r10_bio->devs[i].bio;

	/* now find blocks with errors */
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	for (i=0 ; i < conf->copies ; i++) {
		int  j, d;
		int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
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		tbio = r10_bio->devs[i].bio;
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		if (tbio->bi_end_io != end_sync_read)
			continue;
		if (i == first)
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			continue;
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		if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
			/* We know that the bi_io_vec layout is the same for
			 * both 'first' and 'i', so we just compare them.
			 * All vec entries are PAGE_SIZE;
			 */
			for (j = 0; j < vcnt; j++)
				if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
					   page_address(tbio->bi_io_vec[j].bv_page),
					   PAGE_SIZE))
					break;
			if (j == vcnt)
				continue;
			mddev->resync_mismatches += r10_bio->sectors;
		}
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		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
			/* Don't fix anything. */
			continue;
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		/* Ok, we need to write this bio
		 * First we need to fixup bv_offset, bv_len and
		 * bi_vecs, as the read request might have corrupted these
		 */
		tbio->bi_vcnt = vcnt;
		tbio->bi_size = r10_bio->sectors << 9;
		tbio->bi_idx = 0;
		tbio->bi_phys_segments = 0;
		tbio->bi_hw_segments = 0;
		tbio->bi_hw_front_size = 0;
		tbio->bi_hw_back_size = 0;
		tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
		tbio->bi_flags |= 1 << BIO_UPTODATE;
		tbio->bi_next = NULL;
		tbio->bi_rw = WRITE;
		tbio->bi_private = r10_bio;
		tbio->bi_sector = r10_bio->devs[i].addr;

		for (j=0; j < vcnt ; j++) {
			tbio->bi_io_vec[j].bv_offset = 0;
			tbio->bi_io_vec[j].bv_len = PAGE_SIZE;

			memcpy(page_address(tbio->bi_io_vec[j].bv_page),
			       page_address(fbio->bi_io_vec[j].bv_page),
			       PAGE_SIZE);
		}
		tbio->bi_end_io = end_sync_write;

		d = r10_bio->devs[i].devnum;
		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
		atomic_inc(&r10_bio->remaining);
		md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);

		tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
		tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
		generic_make_request(tbio);
	}

done:
	if (atomic_dec_and_test(&r10_bio->remaining)) {
		md_done_sync(mddev, r10_bio->sectors, 1);
		put_buf(r10_bio);
	}
}

/*
 * Now for the recovery code.
 * Recovery happens across physical sectors.
 * We recover all non-is_sync drives by finding the virtual address of
 * each, and then choose a working drive that also has that virt address.
 * There is a separate r10_bio for each non-in_sync drive.
 * Only the first two slots are in use. The first for reading,
 * The second for writing.
 *
 */

static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
{
	conf_t *conf = mddev_to_conf(mddev);
	int i, d;
	struct bio *bio, *wbio;


	/* move the pages across to the second bio
	 * and submit the write request
	 */
	bio = r10_bio->devs[0].bio;
	wbio = r10_bio->devs[1].bio;
	for (i=0; i < wbio->bi_vcnt; i++) {
		struct page *p = bio->bi_io_vec[i].bv_page;
		bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page;
		wbio->bi_io_vec[i].bv_page = p;
	}
	d = r10_bio->devs[1].devnum;

	atomic_inc(&conf->mirrors[d].rdev->nr_pending);
	md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
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	if (test_bit(R10BIO_Uptodate, &r10_bio->state))
		generic_make_request(wbio);
	else
		bio_endio(wbio, wbio->bi_size, -EIO);
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}


/*
 * This is a kernel thread which:
 *
 *	1.	Retries failed read operations on working mirrors.
 *	2.	Updates the raid superblock when problems encounter.
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 *	3.	Performs writes following reads for array synchronising.
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 */

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static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
{
	int sect = 0; /* Offset from r10_bio->sector */
	int sectors = r10_bio->sectors;
	mdk_rdev_t*rdev;
	while(sectors) {
		int s = sectors;
		int sl = r10_bio->read_slot;
		int success = 0;
		int start;

		if (s > (PAGE_SIZE>>9))
			s = PAGE_SIZE >> 9;

		rcu_read_lock();
		do {
			int d = r10_bio->devs[sl].devnum;
			rdev = rcu_dereference(conf->mirrors[d].rdev);
			if (rdev &&
			    test_bit(In_sync, &rdev->flags)) {
				atomic_inc(&rdev->nr_pending);
				rcu_read_unlock();
				success = sync_page_io(rdev->bdev,
						       r10_bio->devs[sl].addr +
						       sect + rdev->data_offset,
						       s<<9,
						       conf->tmppage, READ);
				rdev_dec_pending(rdev, mddev);
				rcu_read_lock();
				if (success)
					break;
			}
			sl++;
			if (sl == conf->copies)
				sl = 0;
		} while (!success && sl != r10_bio->read_slot);
		rcu_read_unlock();

		if (!success) {
			/* Cannot read from anywhere -- bye bye array */
			int dn = r10_bio->devs[r10_bio->read_slot].devnum;
			md_error(mddev, conf->mirrors[dn].rdev);
			break;
		}

		start = sl;
		/* write it back and re-read */
		rcu_read_lock();
		while (sl != r10_bio->read_slot) {
			int d;
			if (sl==0)
				sl = conf->copies;
			sl--;
			d = r10_bio->devs[sl].devnum;
			rdev = rcu_dereference(conf->mirrors[d].rdev);
			if (rdev &&
			    test_bit(In_sync, &rdev->flags)) {
				atomic_inc(&rdev->nr_pending);
				rcu_read_unlock();
				atomic_add(s, &rdev->corrected_errors);
				if (sync_page_io(rdev->bdev,
						 r10_bio->devs[sl].addr +
						 sect + rdev->data_offset,
						 s<<9, conf->tmppage, WRITE)
				    == 0)
					/* Well, this device is dead */
					md_error(mddev, rdev);
				rdev_dec_pending(rdev, mddev);
				rcu_read_lock();
			}
		}
		sl = start;
		while (sl != r10_bio->read_slot) {
			int d;
			if (sl==0)
				sl = conf->copies;
			sl--;
			d = r10_bio->devs[sl].devnum;
			rdev = rcu_dereference(conf->mirrors[d].rdev);
			if (rdev &&
			    test_bit(In_sync, &rdev->flags)) {
				char b[BDEVNAME_SIZE];
				atomic_inc(&rdev->nr_pending);
				rcu_read_unlock();
				if (sync_page_io(rdev->bdev,
						 r10_bio->devs[sl].addr +
						 sect + rdev->data_offset,
						 s<<9, conf->tmppage, READ) == 0)
					/* Well, this device is dead */
					md_error(mddev, rdev);
				else
					printk(KERN_INFO
					       "raid10:%s: read error corrected"
					       " (%d sectors at %llu on %s)\n",
					       mdname(mddev), s,
					       (unsigned long long)sect+
					            rdev->data_offset,
					       bdevname(rdev->bdev, b));

				rdev_dec_pending(rdev, mddev);
				rcu_read_lock();
			}
		}
		rcu_read_unlock();

		sectors -= s;
		sect += s;
	}
}

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static void raid10d(mddev_t *mddev)
{
	r10bio_t *r10_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);

	for (;;) {
		char b[BDEVNAME_SIZE];
		spin_lock_irqsave(&conf->device_lock, flags);
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		if (conf->pending_bio_list.head) {
			bio = bio_list_get(&conf->pending_bio_list);
			blk_remove_plug(mddev->queue);
			spin_unlock_irqrestore(&conf->device_lock, flags);
			/* flush any pending bitmap writes to disk before proceeding w/ I/O */
			if (bitmap_unplug(mddev->bitmap) != 0)
				printk("%s: bitmap file write failed!\n", mdname(mddev));

			while (bio) { /* submit pending writes */
				struct bio *next = bio->bi_next;
				bio->bi_next = NULL;
				generic_make_request(bio);
				bio = next;
			}
			unplug = 1;

			continue;
		}

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		if (list_empty(head))
			break;
		r10_bio = list_entry(head->prev, r10bio_t, retry_list);
		list_del(head->prev);
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		conf->nr_queued--;
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		spin_unlock_irqrestore(&conf->device_lock, flags);

		mddev = r10_bio->mddev;
		conf = mddev_to_conf(mddev);
		if (test_bit(R10BIO_IsSync, &r10_bio->state)) {
			sync_request_write(mddev, r10_bio);
			unplug = 1;
		} else 	if (test_bit(R10BIO_IsRecover, &r10_bio->state)) {
			recovery_request_write(mddev, r10_bio);
			unplug = 1;
		} else {
			int mirror;
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			/* we got a read error. Maybe the drive is bad.  Maybe just
			 * the block and we can fix it.
			 * We freeze all other IO, and try reading the block from
			 * other devices.  When we find one, we re-write
			 * and check it that fixes the read error.
			 * This is all done synchronously while the array is
			 * frozen.
			 */
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			if (mddev->ro == 0) {
				freeze_array(conf);
				fix_read_error(conf, mddev, r10_bio);
				unfreeze_array(conf);
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			}

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			bio = r10_bio->devs[r10_bio->read_slot].bio;
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			r10_bio->devs[r10_bio->read_slot].bio =
				mddev->ro ? IO_BLOCKED : NULL;
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			bio_put(bio);
			mirror = read_balance(conf, r10_bio);
			if (mirror == -1) {
				printk(KERN_ALERT "raid10: %s: unrecoverable I/O"
				       " read error for block %llu\n",
				       bdevname(bio->bi_bdev,b),
				       (unsigned long long)r10_bio->sector);
				raid_end_bio_io(r10_bio);
			} else {
				rdev = conf->mirrors[mirror].rdev;
				if (printk_ratelimit())
					printk(KERN_ERR "raid10: %s: redirecting sector %llu to"
					       " another mirror\n",
					       bdevname(rdev->bdev,b),
					       (unsigned long long)r10_bio->sector);
				bio = bio_clone(r10_bio->master_bio, GFP_NOIO);
				r10_bio->devs[r10_bio->read_slot].bio = bio;
				bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr
					+ rdev->data_offset;
				bio->bi_bdev = rdev->bdev;
				bio->bi_rw = READ;
				bio->bi_private = r10_bio;
				bio->bi_end_io = raid10_end_read_request;
				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;
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	BUG_ON(conf->r10buf_pool);
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	conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
	if (!conf->r10buf_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.
 *
 * Resync and recovery are handled very differently.
 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
 *
 * For resync, we iterate over virtual addresses, read all copies,
 * and update if there are differences.  If only one copy is live,
 * skip it.
 * For recovery, we iterate over physical addresses, read a good
 * value for each non-in_sync drive, and over-write.
 *
 * So, for recovery we may have several outstanding complex requests for a
 * given address, one for each out-of-sync device.  We model this by allocating
 * a number of r10_bio structures, one for each out-of-sync device.
 * As we setup these structures, we collect all bio's together into a list
 * which we then process collectively to add pages, and then process again
 * to pass to generic_make_request.
 *
 * The r10_bio structures are linked using a borrowed master_bio pointer.
 * This link is counted in ->remaining.  When the r10_bio that points to NULL
 * has its remaining count decremented to 0, the whole complex operation
 * is complete.
 *
 */

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static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
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{
	conf_t *conf = mddev_to_conf(mddev);
	r10bio_t *r10_bio;
	struct bio *biolist = NULL, *bio;
	sector_t max_sector, nr_sectors;
	int disk;
	int i;
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	int max_sync;
	int sync_blocks;
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	sector_t sectors_skipped = 0;
	int chunks_skipped = 0;

	if (!conf->r10buf_pool)
		if (init_resync(conf))
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			return 0;
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 skipped:
	max_sector = mddev->size << 1;
	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
		max_sector = mddev->resync_max_sectors;
	if (sector_nr >= max_sector) {
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		/* If we aborted, we need to abort the
		 * sync on the 'current' bitmap chucks (there can
		 * be several when recovering multiple devices).
		 * as we may have started syncing it but not finished.
		 * We can find the current address in
		 * mddev->curr_resync, but for recovery,
		 * we need to convert that to several
		 * virtual addresses.
		 */
		if (mddev->curr_resync < max_sector) { /* aborted */
			if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
				bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
						&sync_blocks, 1);
			else for (i=0; i<conf->raid_disks; i++) {
				sector_t sect =
					raid10_find_virt(conf, mddev->curr_resync, i);
				bitmap_end_sync(mddev->bitmap, sect,
						&sync_blocks, 1);
			}
		} else /* completed sync */
			conf->fullsync = 0;

		bitmap_close_sync(mddev->bitmap);
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		close_sync(conf);
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		*skipped = 1;
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		return sectors_skipped;
	}
	if (chunks_skipped >= conf->raid_disks) {
		/* if there has been nothing to do on any drive,
		 * then there is nothing to do at all..
		 */
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		*skipped = 1;
		return (max_sector - sector_nr) + sectors_skipped;
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	}

	/* make sure whole request will fit in a chunk - if chunks
	 * are meaningful
	 */
	if (conf->near_copies < conf->raid_disks &&
	    max_sector > (sector_nr | conf->chunk_mask))
		max_sector = (sector_nr | conf->chunk_mask) + 1;
	/*
	 * If there is non-resync activity waiting for us then
	 * put in a delay to throttle resync.
	 */
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	if (!go_faster && conf->nr_waiting)
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		msleep_interruptible(1000);

	/* Again, very different code for resync and recovery.
	 * Both must result in an r10bio with a list of bios that
	 * have bi_end_io, bi_sector, bi_bdev set,
	 * and bi_private set to the r10bio.
	 * For recovery, we may actually create several r10bios
	 * with 2 bios in each, that correspond to the bios in the main one.
	 * In this case, the subordinate r10bios link back through a
	 * borrowed master_bio pointer, and the counter in the master
	 * includes a ref from each subordinate.
	 */
	/* First, we decide what to do and set ->bi_end_io
	 * To end_sync_read if we want to read, and
	 * end_sync_write if we will want to write.
	 */

1698
	max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
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	if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
		/* recovery... the complicated one */
		int i, j, k;
		r10_bio = NULL;

		for (i=0 ; i<conf->raid_disks; i++)
			if (conf->mirrors[i].rdev &&
1706
			    !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) {
1707
				int still_degraded = 0;
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				/* want to reconstruct this device */
				r10bio_t *rb2 = r10_bio;
1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726
				sector_t sect = raid10_find_virt(conf, sector_nr, i);
				int must_sync;
				/* Unless we are doing a full sync, we only need
				 * to recover the block if it is set in the bitmap
				 */
				must_sync = bitmap_start_sync(mddev->bitmap, sect,
							      &sync_blocks, 1);
				if (sync_blocks < max_sync)
					max_sync = sync_blocks;
				if (!must_sync &&
				    !conf->fullsync) {
					/* yep, skip the sync_blocks here, but don't assume
					 * that there will never be anything to do here
					 */
					chunks_skipped = -1;
					continue;
				}
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				r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
1729
				raise_barrier(conf, rb2 != NULL);
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				atomic_set(&r10_bio->remaining, 0);

				r10_bio->master_bio = (struct bio*)rb2;
				if (rb2)
					atomic_inc(&rb2->remaining);
				r10_bio->mddev = mddev;
				set_bit(R10BIO_IsRecover, &r10_bio->state);
1737 1738
				r10_bio->sector = sect;

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				raid10_find_phys(conf, r10_bio);
1740 1741 1742 1743 1744 1745
				/* Need to check if this section will still be
				 * degraded
				 */
				for (j=0; j<conf->copies;j++) {
					int d = r10_bio->devs[j].devnum;
					if (conf->mirrors[d].rdev == NULL ||
1746
					    test_bit(Faulty, &conf->mirrors[d].rdev->flags)) {
1747
						still_degraded = 1;
1748 1749
						break;
					}
1750 1751 1752 1753
				}
				must_sync = bitmap_start_sync(mddev->bitmap, sect,
							      &sync_blocks, still_degraded);

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				for (j=0; j<conf->copies;j++) {
					int d = r10_bio->devs[j].devnum;
					if (conf->mirrors[d].rdev &&
1757
					    test_bit(In_sync, &conf->mirrors[d].rdev->flags)) {
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						/* This is where we read from */
						bio = r10_bio->devs[0].bio;
						bio->bi_next = biolist;
						biolist = bio;
						bio->bi_private = r10_bio;
						bio->bi_end_io = end_sync_read;
						bio->bi_rw = 0;
						bio->bi_sector = r10_bio->devs[j].addr +
							conf->mirrors[d].rdev->data_offset;
						bio->bi_bdev = conf->mirrors[d].rdev->bdev;
						atomic_inc(&conf->mirrors[d].rdev->nr_pending);
						atomic_inc(&r10_bio->remaining);
						/* and we write to 'i' */

						for (k=0; k<conf->copies; k++)
							if (r10_bio->devs[k].devnum == i)
								break;
						bio = r10_bio->devs[1].bio;
						bio->bi_next = biolist;
						biolist = bio;
						bio->bi_private = r10_bio;
						bio->bi_end_io = end_sync_write;
						bio->bi_rw = 1;
						bio->bi_sector = r10_bio->devs[k].addr +
							conf->mirrors[i].rdev->data_offset;
						bio->bi_bdev = conf->mirrors[i].rdev->bdev;

						r10_bio->devs[0].devnum = d;
						r10_bio->devs[1].devnum = i;

						break;
					}
				}
				if (j == conf->copies) {
1792 1793 1794 1795 1796 1797 1798
					/* Cannot recover, so abort the recovery */
					put_buf(r10_bio);
					r10_bio = rb2;
					if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery))
						printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n",
						       mdname(mddev));
					break;
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				}
			}
		if (biolist == NULL) {
			while (r10_bio) {
				r10bio_t *rb2 = r10_bio;
				r10_bio = (r10bio_t*) rb2->master_bio;
				rb2->master_bio = NULL;
				put_buf(rb2);
			}
			goto giveup;
		}
	} else {
		/* resync. Schedule a read for every block at this virt offset */
		int count = 0;
1813 1814 1815 1816 1817 1818 1819 1820 1821 1822

		if (!bitmap_start_sync(mddev->bitmap, sector_nr,
				       &sync_blocks, mddev->degraded) &&
		    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
			/* We can skip this block */
			*skipped = 1;
			return sync_blocks + sectors_skipped;
		}
		if (sync_blocks < max_sync)
			max_sync = sync_blocks;
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		r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);

		r10_bio->mddev = mddev;
		atomic_set(&r10_bio->remaining, 0);
1827 1828
		raise_barrier(conf, 0);
		conf->next_resync = sector_nr;
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		r10_bio->master_bio = NULL;
		r10_bio->sector = sector_nr;
		set_bit(R10BIO_IsSync, &r10_bio->state);
		raid10_find_phys(conf, r10_bio);
		r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1;

		for (i=0; i<conf->copies; i++) {
			int d = r10_bio->devs[i].devnum;
			bio = r10_bio->devs[i].bio;
			bio->bi_end_io = NULL;
			if (conf->mirrors[d].rdev == NULL ||
1841
			    test_bit(Faulty, &conf->mirrors[d].rdev->flags))
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1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880
				continue;
			atomic_inc(&conf->mirrors[d].rdev->nr_pending);
			atomic_inc(&r10_bio->remaining);
			bio->bi_next = biolist;
			biolist = bio;
			bio->bi_private = r10_bio;
			bio->bi_end_io = end_sync_read;
			bio->bi_rw = 0;
			bio->bi_sector = r10_bio->devs[i].addr +
				conf->mirrors[d].rdev->data_offset;
			bio->bi_bdev = conf->mirrors[d].rdev->bdev;
			count++;
		}

		if (count < 2) {
			for (i=0; i<conf->copies; i++) {
				int d = r10_bio->devs[i].devnum;
				if (r10_bio->devs[i].bio->bi_end_io)
					rdev_dec_pending(conf->mirrors[d].rdev, mddev);
			}
			put_buf(r10_bio);
			biolist = NULL;
			goto giveup;
		}
	}

	for (bio = biolist; bio ; bio=bio->bi_next) {

		bio->bi_flags &= ~(BIO_POOL_MASK - 1);
		if (bio->bi_end_io)
			bio->bi_flags |= 1 << BIO_UPTODATE;
		bio->bi_vcnt = 0;
		bio->bi_idx = 0;
		bio->bi_phys_segments = 0;
		bio->bi_hw_segments = 0;
		bio->bi_size = 0;
	}

	nr_sectors = 0;
1881 1882
	if (sector_nr + max_sync < max_sector)
		max_sector = sector_nr + max_sync;
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	do {
		struct page *page;
		int len = PAGE_SIZE;
		disk = 0;
		if (sector_nr + (len>>9) > max_sector)
			len = (max_sector - sector_nr) << 9;
		if (len == 0)
			break;
		for (bio= biolist ; bio ; bio=bio->bi_next) {
			page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
			if (bio_add_page(bio, page, len, 0) == 0) {
				/* stop here */
				struct bio *bio2;
				bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
				for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) {
					/* remove last page from this bio */
					bio2->bi_vcnt--;
					bio2->bi_size -= len;
					bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
				}
				goto bio_full;
			}
			disk = i;
		}
		nr_sectors += len>>9;
		sector_nr += len>>9;
	} while (biolist->bi_vcnt < RESYNC_PAGES);
 bio_full:
	r10_bio->sectors = nr_sectors;

	while (biolist) {
		bio = biolist;
		biolist = biolist->bi_next;

		bio->bi_next = NULL;
		r10_bio = bio->bi_private;
		r10_bio->sectors = nr_sectors;

		if (bio->bi_end_io == end_sync_read) {
			md_sync_acct(bio->bi_bdev, nr_sectors);
			generic_make_request(bio);
		}
	}

1927 1928 1929 1930 1931 1932
	if (sectors_skipped)
		/* pretend they weren't skipped, it makes
		 * no important difference in this case
		 */
		md_done_sync(mddev, sectors_skipped, 1);

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	return sectors_skipped + nr_sectors;
 giveup:
	/* There is nowhere to write, so all non-sync
	 * drives must be failed, so try the next chunk...
	 */
	{
1939
	sector_t sec = max_sector - sector_nr;
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	sectors_skipped += sec;
	chunks_skipped ++;
	sector_nr = max_sector;
	goto skipped;
	}
}

static int run(mddev_t *mddev)
{
	conf_t *conf;
	int i, disk_idx;
	mirror_info_t *disk;
	mdk_rdev_t *rdev;
	struct list_head *tmp;
1954
	int nc, fc, fo;
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	sector_t stride, size;

1957 1958 1959
	if (mddev->chunk_size == 0) {
		printk(KERN_ERR "md/raid10: non-zero chunk size required.\n");
		return -EINVAL;
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	}
1961

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	nc = mddev->layout & 255;
	fc = (mddev->layout >> 8) & 255;
1964
	fo = mddev->layout & (1<<16);
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	if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
1966
	    (mddev->layout >> 17)) {
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		printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n",
		       mdname(mddev), mddev->layout);
		goto out;
	}
	/*
	 * copy the already verified devices into our private RAID10
	 * bookkeeping area. [whatever we allocate in run(),
	 * should be freed in stop()]
	 */
1976
	conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
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	mddev->private = conf;
	if (!conf) {
		printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
			mdname(mddev));
		goto out;
	}
1983
	conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
L
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				 GFP_KERNEL);
	if (!conf->mirrors) {
		printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
		       mdname(mddev));
		goto out_free_conf;
	}
1990 1991 1992 1993

	conf->tmppage = alloc_page(GFP_KERNEL);
	if (!conf->tmppage)
		goto out_free_conf;
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	conf->near_copies = nc;
	conf->far_copies = fc;
	conf->copies = nc*fc;
1998
	conf->far_offset = fo;
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	conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1;
	conf->chunk_shift = ffz(~mddev->chunk_size) - 9;
2001 2002 2003 2004 2005 2006 2007
	if (fo)
		conf->stride = 1 << conf->chunk_shift;
	else {
		stride = mddev->size >> (conf->chunk_shift-1);
		sector_div(stride, fc);
		conf->stride = stride << conf->chunk_shift;
	}
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2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042
	conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
						r10bio_pool_free, conf);
	if (!conf->r10bio_pool) {
		printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
			mdname(mddev));
		goto out_free_conf;
	}

	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))
			mddev->queue->max_sectors = (PAGE_SIZE>>9);

		disk->head_position = 0;
	}
	conf->raid_disks = mddev->raid_disks;
	conf->mddev = mddev;
	spin_lock_init(&conf->device_lock);
	INIT_LIST_HEAD(&conf->retry_list);

	spin_lock_init(&conf->resync_lock);
2043
	init_waitqueue_head(&conf->wait_barrier);
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2045 2046 2047 2048
	/* need to check that every block has at least one working mirror */
	if (!enough(conf)) {
		printk(KERN_ERR "raid10: not enough operational mirrors for %s\n",
		       mdname(mddev));
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		goto out_free_conf;
	}

	mddev->degraded = 0;
	for (i = 0; i < conf->raid_disks; i++) {

		disk = conf->mirrors + i;

2057 2058
		if (!disk->rdev ||
		    !test_bit(In_sync, &rdev->flags)) {
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			disk->head_position = 0;
			mddev->degraded++;
		}
	}


	mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10");
	if (!mddev->thread) {
		printk(KERN_ERR
		       "raid10: couldn't allocate thread for %s\n",
		       mdname(mddev));
		goto out_free_conf;
	}

	printk(KERN_INFO
		"raid10: raid set %s active with %d out of %d devices\n",
		mdname(mddev), mddev->raid_disks - mddev->degraded,
		mddev->raid_disks);
	/*
	 * Ok, everything is just fine now
	 */
2080 2081 2082 2083 2084 2085 2086
	if (conf->far_offset) {
		size = mddev->size >> (conf->chunk_shift-1);
		size *= conf->raid_disks;
		size <<= conf->chunk_shift;
		sector_div(size, conf->far_copies);
	} else
		size = conf->stride * conf->raid_disks;
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	sector_div(size, conf->near_copies);
	mddev->array_size = size/2;
	mddev->resync_max_sectors = size;

2091 2092 2093
	mddev->queue->unplug_fn = raid10_unplug;
	mddev->queue->issue_flush_fn = raid10_issue_flush;

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	/* Calculate max read-ahead size.
	 * We need to readahead at least twice a whole stripe....
	 * maybe...
	 */
	{
2099
		int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE);
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		stripe /= conf->near_copies;
		if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
			mddev->queue->backing_dev_info.ra_pages = 2* stripe;
	}

	if (conf->near_copies < mddev->raid_disks)
		blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
	return 0;

out_free_conf:
	if (conf->r10bio_pool)
		mempool_destroy(conf->r10bio_pool);
2112
	safe_put_page(conf->tmppage);
2113
	kfree(conf->mirrors);
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	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->r10bio_pool)
		mempool_destroy(conf->r10bio_pool);
2129
	kfree(conf->mirrors);
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	kfree(conf);
	mddev->private = NULL;
	return 0;
}

2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154
static void raid10_quiesce(mddev_t *mddev, int state)
{
	conf_t *conf = mddev_to_conf(mddev);

	switch(state) {
	case 1:
		raise_barrier(conf, 0);
		break;
	case 0:
		lower_barrier(conf);
		break;
	}
	if (mddev->thread) {
		if (mddev->bitmap)
			mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
		else
			mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
		md_wakeup_thread(mddev->thread);
	}
}
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2156
static struct mdk_personality raid10_personality =
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2157 2158
{
	.name		= "raid10",
2159
	.level		= 10,
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	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid10_add_disk,
	.hot_remove_disk= raid10_remove_disk,
	.spare_active	= raid10_spare_active,
	.sync_request	= sync_request,
2170
	.quiesce	= raid10_quiesce,
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};

static int __init raid_init(void)
{
2175
	return register_md_personality(&raid10_personality);
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}

static void raid_exit(void)
{
2180
	unregister_md_personality(&raid10_personality);
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}

module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md-personality-9"); /* RAID10 */
2187
MODULE_ALIAS("md-raid10");
2188
MODULE_ALIAS("md-level-10");